WO2008097952A1

WO2008097952A1 - Functionalized, crosslinked polyolefin foams and methods for making the same

Info

Publication number: WO2008097952A1
Application number: PCT/US2008/053026
Authority: WO
Inventors: Stephen Cheng
Original assignee: Dow Global Technologies LLC
Current assignee: Dow Global Technologies LLC
Priority date: 2007-02-06
Filing date: 2008-02-05
Publication date: 2008-08-14
Anticipated expiration: 2009-08-06
Also published as: TW200848454A; AR065212A1

Abstract

The invention provides a process for producing a functionalized, crosslinked foam, said process comprising thermally treating a composition comprising the following: a) at least one polyolefin; b) at least one blowing agent, c) at least one initiator, and d) at least one grafting agent represented by Compound I, as shown below: (I), wherein R1 is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched, R2 is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched, R3 is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched, R4 is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched, Z is either OH, SH, NH2 or NHR5, and wherein R5 is a C1-C20 hydrocarbyl radical, which is linear or branched; and and wherein the compound is grafted onto the polyolefin, while the polyolefin is crosslinked and foamed, to form a functionalized, crosslinked foam.

Description

FUNCTIONALIZED, CROSSLINKED POLYOLEFIN FOAMS AND METHODS FOR MAKING THE SAME

REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No.

60/899,729, filed on February 6, 2007, and fully incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates to functionalized, crosslinked polyolefin compositions, articles prepared therefrom, and methods for making the same.

Athletic footwear construction contains a part, known as midsole, made from, in part, crosslinked polyolefin or polyurethane foams. Usage of polyolefin foams is growing, due to lighter density polyolefin materials, which in turn, can be used to make lighter weight shoes. Ethylene-vinylacetate (EVA), the traditional material used for midsole applications, does not meet all the emerging, more stringent, functional requirements, and polyethylene elastomers (POE), such as Engage™ (ethylene-octene or ethylene-butene copolymers) resins, are added to EVA formulations to improve the performance of the foams over that of pure EVA. POE-rich foams that approach 100 weight percent POE are desirable because of significant improvement in mechanical properties, one of which is compression set. However, POE lacks polarity, and traditional primer/adhesives, used in the footwear industry, do not provide adequate adhesion of the midsole foam to the shoe upper or rubber outsole, and this lack of adhesion prevents POE-rich formulations from being adopted.

As discussed above, primers and adhesives are used in the footwear industry to bind foam components to other various components of a shoe. Due to the difficulty in priming a foam surface, containing a POE content up to 45-50 weight percent of the total polymer content, with waterborne primers, the industry uses UV-activating materials to modify the foam surface for better adhesion. However, POE-rich formulations, for example 90 weight percent or more (based on the total weight of the foam) can not be bonded reliably in the existing footwear assembly process. Even midsole formulations with POE-content greater than 50% weight are not commonly adopted by the industry due to adhesion concerns.

To increase the polarity, and thus the adhesion, of non-polar POE foams, the POE can be blended with more polar polymers, or the non-polar POE can be modified, for example via grafting. Incorporation of polar polymer into blends is not novel, and the grafting of maleic anhydride is known and practiced. Both of theses modifications can increase cost, and, in particular, the grafting of polymers can lead to increased cost in extra processing step(s) and/or in the removal of residual unreactive grafting agent and/or unreactive peroxide. International Publication No. WO 2005/066279 discloses a crossslinkable, expandable polymeric composition, comprising a free -radical crosslinkable polymer, a free-radical inducing species, a crosslinking-profile modifier, and a blowing agent. International Publication No. WO 2005/066281 discloses a polymeric composition comprising a free-radical reactive polymer, an organic peroxide, and a graftable stable organic free radical. International Publication No. WO 2005/066280 discloses an improved process to form crosslinked polymer compositions, in which the crosslinking reaction can occur faster, and at hotter processing conditions. The polymer composition comprises a free radical crosslinkable polymer, a free-radical inducing species, and a crosslinking temperature profile modifier. International Publication Nos. WO 2005/066282, WO 2005/063895, are each directed to a rheology-modified composition. International Publication No. WO 2005/063896 is directed to a free-radical crosslinkable composition.

Japanese Patent Application No. 2002-201755 (Abstract) discloses a composition for use in a crosslinked or uncrosslinked foam. The composition contains an ethylene/α-olefin copolymer mixture, a foaming agent, and optionally, an organic peroxide and a crosslinking aid. Japanese Patent Application No. 04-320076 (Abstract) discloses a bonding layer composed of an ethylenic copolymer containing an acid anhydride group.

There remains a need for a cost effective means of generating a functionalized, crosslinked polyolefin foam, by functionalizing a polyolefin, while crosslinking and foaming the polyolefin, to form the final foam product, such as a compression molded foam, and in which the foam contains a sufficient amount of polar groups to provide good adhesion to polar polymers using conventional primers and adhesives. In addition, there is a need for a cost effective process to form polyolefin-rich foams that have at least 50 weight percent, and preferably at least 80 weight percent, or more, polyolefin, and in which such process simultaneously produces a functionalized, crosslinked polyolefin foam for bonding to other polar materials. There is a further need for a process of generating a functionalized, crosslinked polyolefin foam using a minimal amount of functionalizing agent.

There is also a need for a functionalized, crosslinked foam that has good adhesion strength to polar primers and adhesives, as required for the footwear industry, and which, optionally, do not require UV-activating primers. There is a further need for a functionalized, crosslinked foam with a substantially uniform hardness throughout the thickness of the foam. Some of these needs and others have been met by the following invention.

SUMMARY OF THE INVENTION

A process for producing a functionalized, crosslinked foam, said process comprising thermally treating a composition comprising the following: a) at least one polyolefin; b) at least one blowing agent, c) at least one initiator, and d) at least one grafting agent represented by Compound I, as shown below:

(D, wherein R¹ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched,

R is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched, R³ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched,

R⁴ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched,

Z is either OH, SH, NH₂ or NHR⁵, and wherein R⁵ is a C1-C20 hydrocarbyl radical, which is linear or branched; and wherein the compound is grafted onto the polyolefin, while the polyolefin is crosslinked and foamed, to form a functionalized, crosslinked foam.

The invention also provides crosslinked foams prepared from an inventive process, and articles prepared from the same.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts a schematic of the crosslinking of a hydrocarbon polymer using dicumylperoxide.

Figure 2 depicts a schematic of the mechanism of TEMPO grafting onto a polymer backbone.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides an in-situ grafting reaction that occurs during the foaming and peroxide cure of a polymer backbone. During the peroxide crosslinking process, a polar functional molecule, such as 4-hydroxy-TEMPO, is grafted onto free- radical sites on the polymer backbone. The process results in one or more polar moieties grafted in-situ onto the polymer backbone. The invention is particularly suitable for the manufacturing of polyolefin foams for footwear. In a preferred embodiment, the polar moiety also comprises a reactive functional group, such as hydroxyl group, which can react chemically with other groups, such as isocyanate groups. In particular, the invention provides a process for producing a functionalized, crosslinked foam, said process comprising thermally treating a composition comprising the following: a) at least one polyolefin; b) at least one blowing agent, c) at least one initiator, and d) at least one grafting agent represented by Compound I, as shown below:

R² is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched,

R³ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched,

Z is either OH, SH, NH₂ or NHR⁵, and wherein R⁵ is a C1-C20 hydrocarbyl radical, which is linear or branched; and and wherein the compound is grafted onto the polyolefin, while the polyolefin is crosslinked and foamed, to form a functionalized, crosslinked foam.

In another embodiment, the compound is grafted onto the polyolefin, with an efficiency greater than 25 percent, and preferably greater than 50 percent, based on the weight of Compound I, while the polyolefin is crosslinked and foamed, to form a functionalized, crosslinked foam. Grafting efficiency can be determined using a 13C NMR model study as described herein.

In another embodiment, the initiator is an organic peroxide. In a further embodiment, the organic peroxide is present in an amount greater than the amount of Compound I.

In another embodiment, the initiator is an organic peroxide, and the crosslinked foam has a gel content, as measured according to ASTM D-2765-01, Procedure A, of at least 50 weight percent, based on the total weight of the foam.

In another embodiment, the polyolefin is present in an amount greater than, or equal to, 50 weight percent, and preferably greater than, or equal to, 70 weight percent, and more preferably greater than, or equal to, 80 weight percent, and even more preferably greater than, or equal to, 90 weight percent, based on the total weight of the composition.

In another embodiment, the blowing agent is a chemical blowing agent. In one embodiment, the polyolefin is an ethylene-based polymer.

In one embodiment, the polyolefin is an ethylene/α-olefin interpolymer. In a further embodiment, the α-olefin is a C3-C10 α-olefin, and preferably propylene, 1- butene, 1-hexene, or 1-octene. In a further embodiment, the ethylene/α-olefin interpolymer is a homogeneously branched linear interpolymer or a homogeneously branched substantially linear interpolymer. In another embodiment, the ethylene/α- olefin interpolymer is a homogeneously branched substantially linear interpolymer.

In another embodiment, the polyolefin is an ethylene/α-olefin copolymer. In a further embodiment, the α-olefin is a C3-C10 α-olefin, and preferably propylene, 1- butene, 1-hexene, or 1-octene. In a further embodiment, the ethylene/α-olefin copolymer is a homogeneously branched linear copolymer or a homogeneously branched substantially linear copolymer. In another embodiment, the ethylene/α- olefin copolymer is a homogeneously branched substantially linear copolymer.

In another embodiment, the ethylene/α-olefin interpolymer has a density from 0.850 g/cc to 0.970 g/cc, and preferably 0.855 g/cc to 0.960 g/cc. In a further embodiment, the ethylene/α-olefin interpolymer has a density from 0.857 g/cc to 0.910 g/cc. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, the ethylene/α-olefin interpolymer has a melt index from 0.001 g/10 min to 1000 g/10 min, preferably from 0.05 g/10 min to 300 g/10 min, and more preferably from 0.1 g/10 min to 200 g/10 min. In a further embodiment, the ethylene/α-olefin interpolymer has a melt index from 0.5 g/10 min to 30 g/10 min. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, the polyolefin is an olefin multi-block interpolymer. In a further embodiment, the olefin multi-block interpolymer is an ethylene/α-olefin multi-block interpolymer.

In another embodiment, the polyolefin is a propylene-based polymer.

In another embodiment, the composition is thermally treated for a period of time to crosslink the foam to a gel content of at least 50 weight percent (ASTM D- 2765-01), based on the total weight of the foam.

In another embodiment, the composition is thermally treated for a period greater than, or equal to, 8 minutes, preferably greater than, or equal to, 10 minutes. In a further embodiment, the initiator is dicumylperoxide.

In another embodiment, the composition is thermally treated at a temperature greater than, or equal to, 160⁰C, preferably greater than, or equal to, 170⁰C. In a further embodiment, the initiator is dicumylperoxide.

In another embodiment, the crosslinked foam comprises at least 0.008 mole percent of reactive "Z group," based on the total moles of carbon centers on the polyolefin. The mole percentage of the reactive "Z group" can be determined from the grafting efficiency, which can be determined from a model 13C NMR study as described herein.

In another embodiment, the initiator is a peroxide, which is present in an amount from 0.1 phr to 10 phr, more preferably, from 0.5 phr to 5.0 phr, and more preferably, from 0.6 phr to 1.5 phr, based on hundred parts of the polyolefin. In a further embodiment, the initiator is present in an amount from 0.6 phr to 1.3 phr, based on hundred parts of the polyolefin. In another embodiment, the blowing agent is present in an amount less than, or equal to 10.0 phr, preferably less than, or equal to 5.0 phr, and more preferably less than, or equal to 4.0 phr, based on hundred parts of the polyolefin.

In another embodiment, the Compound I is present in an amount greater than, or equal to, 0.05 phr, preferably greater than, or equal to, 0.10 phr, and more preferably greater than, or equal to, 0.15 phr, based on hundred parts of the polyolefin.

In another embodiment, the Compound I is present in an amount less than, or equal to, 0.5 phr, preferably less than, or equal to, 0.3 phr, and more preferably less than, or equal to, 0.25 phr, and even more preferably less than, or equal to, 0.20 phr, based on hundred parts of the polyolefin.

In another embodiment, the Compound I is present in an amount from 0.05 phr to 0.25 phr, preferably from 0.05 to 0.20 phr, and more preferably from 0.05 to 0.15 phr, based on hundred parts of the polyolefin. In another embodiment, the Compound I is present in an greater than, or equal to, 0.25 phr, and preferably greater than, or equal to, 0.50 phr, based on hundred parts of the polyolefin.

In another embodiment, the initiator is a peroxide, and the molar ratio of peroxoyl radical to Compound I is less than, or equal to, 40, preferably less than, or equal to, 35, and more preferably less than, or equal to, 30. For the molar ratio of peroxoyl radical to Compound I, as discussed herein, a 100% percent initiator efficiency is assumed, and thus, there are two moles of peroxoyl radicals for every mole of peroxide group.

In another embodiment, the initiator is a peroxide, and the molar ratio of peroxoyl radical to Compound I is greater than, or equal to, 2.5, preferably greater than, or equal to, 4, and more preferably greater than, or equal to, 6.

In another embodiment, the initiator is a peroxide, and the molar ratio of peroxoyl radical to Compound I is from 2.5 to 40, preferably from 4 to 35, and more preferably from 6 to 30. In a further embodiment, the molar ratio of peroxoyl radical to Compound I is from 6 to 20, preferably from 6 to 15. In another embodiment, the Compound I is present in an amount less than, or equal to 0.25 phr, based on hundred parts of polyolefin, and the molar ratio of peroxoyl radical to Compound I is from 2.5 to 40, preferably from 4 to 35, and more preferably from 6 to 30. In a further embodiment, the molar ratio of peroxoyl radical to Compound I is from 6 to 20, preferably from 6 to 15. In another embodiment, the Compound I is present in an amount less than, or equal to 0.20 phr, based on hundred parts of polyolefin, and the molar ratio of peroxoyl radical to Compound I is from 2.5 to 40, preferably from 4 to 35, and more preferably from 6 to 30. In a further embodiment, the molar ratio of peroxoyl radical to Compound I is from 6 to 20, preferably from 6 to 15. In another embodiment, the composition does not contain an azo blowing agent.

In another embodiment, the Z group of Compound I is a hydroxyl group. In another embodiment, the Z group of Compound I is an amino group. In another embodiment, the Z group of Compound I is a SH group. In another embodiment, the Z group of Compound I is a NHR⁵ group, and wherein R⁵ is a C1-C20 hydrocarbyl radical, which is linear or branched. In another embodiment, the composition comprises two or more types of Compound I, and each type has a Z group different from the other type, and optionally may have a different R¹, R², R³ and/or R⁴ group(s). The inventive process may comprise a combination of two or more embodiments as described herein.

The invention also provides a foam formed by an inventive process.

The invention also provides a foam formed from a composition comprising: a) at least one polyolefin; b) at least one blowing agent, c) at least one initiator, and d) at least one grafting agent represented by Compound I, as shown below:

(D,

wherein R¹ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched, R² is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched,

R⁴ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched, and

Z is either OH, SH, NH₂ or NHR⁵, and wherein R⁵ is a C1-C20 hydrocarbyl radical, which is linear or branched.

In a further embodiment, the Z group on Compound I is present, in the inventive foam, in an amount greater than, or equal to, one Z group per 24,000 carbon centers, and preferably greater than, or equal to, one Z group per 12,000 carbon centers. The amount of Z group can be determined from calculations based on the amount of Compound I, the amount of polyolefin, and the grafting efficiency, which can be determined by a model 13 C NMR study as described herein.

In another embodiment, the inventive foam has a reduction of at least 5 percent, preferably at least 10 percent, and more preferably at least 20 percent, in the "surface hardness (Shore A) to core hardness (Shore A) differential," compared to this differential in a foam, similar in all aspects, except formed without the Compound I. The hardness (Shore A) is measured in accordance with ASTM D-2240-05.

In another embodiment, the foam comprises at least 0.008 mole percent, and preferably at least 0.016 mole percent of reactive "Z group," based on the total moles of Compound I. The mole percentage of reactive "Z group" can be determined from the grafting efficiency, which can be determined by a model 13 C NMR study as described herein

The inventive foam may comprise a combination of two or more embodiments as described herein, and each embodiments may relate to an inventive process as described herein.

The invention also provides an article comprising at least one component formed from an inventive foam. In a further embodiment, the at least one component is a foam substrate. In another embodiment, the article is a shoe sole. In another embodiment, the article is a building material. In another embodiment, the article is an insulation material. In another embodiment, the article is an automotive part. In another embodiment, the article is a shoe component.

The inventive article may comprise a combination of two or more embodiments as described herein, and each embodiments may relate to an inventive foam or an inventive process as described herein.

Polyolefin for Grafting, Crosslinking and Foaming Reactions

Suitable polyolefins include, but are not limited to, ethylene/α-olefin interpolymers, ethylene/propylene/diene interpolymers, ethylene/propylene polymers, ethylene homopolymers, propylene homopolymers, propylene interpolymers, olefin multi-block interpolymers (for example, ethylene/α-olefin multi-block interpolymers) natural rubber, polybutadiene rubber, butyl rubber, and blends thereof.

Suitable ethylene-based polymers fall into four main classifications: (1) highly-branched; (2) heterogeneous linear; (3) homogeneously branched linear; and (4) homogeneously branched substantially linear. Respective polymers can be prepared with Ziegler-Natta catalysts, metallocene or vanadium-based single-site catalysts, or constrained geometry single-site catalysts.

Highly branched ethylene polymers include low density polyethylene (LDPE). Those polymers can be prepared with a free -radical initiator at high temperatures and high pressure. Alternatively, they can be prepared with a coordination catalyst at high temperatures and relatively low pressures. These polymers have a density from about 0.910 g/cc to about 0.940 g/cc, as measured by ASTM D-792-00.

Heterogeneous linear ethylene polymers include linear low density polyethylene (LLDPE), ultra-low density polyethylene (ULDPE), very low density polyethylene (VLDPE), and high density polyethylene (HDPE). Linear low density ethylene polymers have a density from about 0.850 g/cc to about 0.940 g/cc, and typically, a melt index from about 0.01 to about 100 grams per 10 minutes, as measured by ASTM 1238-04 (2.16kg and 19O⁰C). Preferably, the melt index is from about 0.1 to about 50 grams per 10 minutes. Also, preferably, the LLDPE is an interpolymer of ethylene and one or more other alpha olefins having from 3 to 18 carbon atoms, more preferably from 3 to 8 carbon atoms. Preferred α-olefins include propylene, 1-butene, 4-methyl-l-pentene, 1-hexene, and 1-octene, and preferably propylene, 1-butene, 1-hexene and 1-octene, and more preferably 1-butene, 1-hexene and 1-octene. Ultra-low density polyethylene and very low density polyethylene are known interchangeably. These polymers have a density from about 0.870 g/cc to about 0.910 g/cc. High density ethylene polymers are generally homopolymers with a density between about 0.941 g/cc and about 0.965 g/cc.

The terms "homogeneous" and "homogeneously-branched" are used in reference to an ethylene/α-olefin interpolymer, in which the α-olefin comonomer is randomly distributed within a given polymer molecule, and substantially all of the polymer molecules have the same ethylene-to-comonomer ratio. The homogeneously branched ethylene interpolymers that can be used in the practice of this invention include linear ethylene interpolymers, and substantially linear ethylene interpolymers. Included amongst the homogeneously branched linear ethylene interpolymers are ethylene polymers, which lack long chain branching, but do have short chain branches, derived from the comonomer polymerized into the interpolymer, and which are homogeneously distributed, both within the same polymer chain, and between different polymer chains. That is, homogeneously branched linear ethylene interpolymers lack long chain branching, just as is the case for the linear low density polyethylene polymers or linear high density polyethylene polymers, and can be made using uniform branching distribution polymerization processes, as described, for example, by Elston in U.S. Patent 3,645,992. Commercial examples of homogeneously branched linear ethylene/α-olefin interpolymers include TAFMER™ polymers supplied by the Mitsui Chemical Company, and EXACT™ polymers supplied by ExxonMobil Chemical Company.

This homogeneously branched linear polymers are disclosed for example, by Elston in US Patent No. 3,645,992, and subsequent processes to produce such polymers using metallocene catalysts have been developed, as shown, for example, in EP 0 129 368, EP 0 260 999, US Patent No. 4,701,432; US Patent No. 4,937,301; US Patent No. 4, 935,397; US Patent No. 5,055,438; and WO 90/07526, and others. The polymers can be made by conventional polymerization processes (for example, gas phase, slurry, solution, and high pressure).

The substantially linear ethylene interpolymers used in the present invention are described in U.S. Patent Nos. 5,272,236; 5,278,272; 6,054,544; 6,335,410 and 6,723,810; the entire contents of each are herein incorporated by reference. The substantially linear ethylene interpolymers are those in which the comonomer is randomly distributed within a given interpolymer molecule, and in which substantially all of the interpolymer molecules have the same ethylene/comonomer ratio within that interpolymer. In addition, the substantially linear ethylene interpolymers are homogeneously branched ethylene interpolymers having long chain branching (chain branch has more carbon atoms than a branched formed by the incorporation of one comonomer into the polymer backbone). The long chain branches have the same comonomer distribution as the polymer backbone, and can have about the same length as the length of the polymer backbone. "Substantially linear," typically, is in reference to a polymer that is substituted, on average, with 0.01 long chain branches per 1000 total carbons (including both backbone and branch carbons) to 3 long chain branches per 1000 total carbons.

Some polymers may be substituted with 0.01 long chain branches per 1000 total carbons to 1 long chain branch per 1000 total carbons, or from 0.05 long chain branches per 1000 total carbons to 1 long chain branch per 1000 total carbons, or from 0.3 long chain branches per 1000 total carbons to 1 long chain branch per 1000 total carbons. Commercial examples of substantially linear polymers include the ENGAGE™ polymers and AFFINITY™ polymers (both available from The Dow Chemical Company).

The substantially linear ethylene interpolymers form a unique class of homogeneously branched ethylene polymers. They differ substantially from the well- known class of conventional, homogeneously branched linear ethylene interpolymers, described by Elston in U.S. Patent 3,645,992, and, moreover, they are not in the same class as conventional heterogeneous, "Ziegler-Natta catalyst polymerized" linear ethylene polymers (for example, ultra low density polyethylene (ULDPE), linear low density polyethylene (LLDPE) or high density polyethylene (HDPE), made, for example, using the technique disclosed by Anderson et al., in U.S. Patent 4,076,698); nor are they in the same class as high pressure, free-radical initiated, highly branched polyethylenes, such as, for example, low density polyethylene (LDPE), ethylene- acrylic acid (EAA) copolymers and ethylene vinyl acetate (EVA) copolymers. The homogeneously branched, substantially linear ethylene interpolymers useful in the invention have excellent processability, even though they have a relatively narrow molecular weight distribution. Surprisingly, the melt flow ratio (I₁(ZI₂), according to ASTM D 1238-04, of the substantially linear ethylene interpolymers can be varied widely, and essentially independently of the molecular weight distribution (M_w/M_n or MWD). This surprising behavior is completely contrary to conventional homogeneously branched linear ethylene interpolymers, such as those described, for example, by Elston in U.S. 3,645,992, and heterogeneously branched "conventional Ziegler-Natta polymerized" linear polyethylene interpolymers, such as those described, for example, by Anderson et al., in U.S. 4,076,698. Unlike the substantially linear ethylene interpolymers, linear ethylene interpolymers (whether homogeneously or heterogeneously branched) have rheological properties, such that, as the molecular weight distribution increases, the I₁₀/l2 value also increases.

"Long chain branching (LCB)" can be determined by conventional techniques known in the industry, such as ¹³C nuclear magnetic resonance (¹³C NMR) spectroscopy, using, for example, the method of Randall (Rev. Micromole. Chem. Phys., 1989, C29 (2&3), p. 285-297). Two other methods are gel permeation chromatography, coupled with a low angle laser light scattering detector (GPC- LALLS), and gel permeation chromatography, coupled with a differential viscometer detector (GPC-DV). The use of these techniques for long chain branch detection, and the underlying theories, have been well documented in the literature. See, for example, Zimm, B.H. and Stockmayer, W.H., J. Chem. Phys.,17,1301(1949) and Rudin, A., Modern Methods of Polymer Characterization, John Wiley & Sons, New York (1991) pp. 103-112.

Homogeneously-branched substantially linear ethylene polymers include interpolymers of ethylene with at least one C3-C20 alpha-olefin. Optionally other polyene monomers, such as dienes or trienes are included. These polymers generally have a density between about 0.850 g/cc and about 0.960 g/cc. Preferably, the density is from 0.850 g/cc to 0.950 g/cc, more preferably, from 0.857 g/cc to 0.928 g/cc.

In contrast to "substantially linear ethylene polymer," the term "linear ethylene polymer" means that the polymer lacks measurable or demonstrable long chain branches, that is, the polymer is substituted with an average of less than 0.01 long chain branch per 1000 total carbons.

The homogeneous branched ethylene polymers useful in the present invention will preferably have a single melting peak, as measured using Differential Scanning Calorimetry (DSC), in contrast to heterogeneously branched linear ethylene polymers, which have two or more melting peaks, due to the heterogeneously branched polymer's broad branching distribution.

In a preferred embodiment of the invention, an ethylene-based interpolymer is an ethylene/α-olefin interpolymer, comprising at least one α-olefin. In another embodiment, the interpolymer further comprises at least one diene or triene.

Preferred α-olefins contain 3 to 20 carbon atoms, and are preferably propylene, 1- butene, 1-pentene, 1-hexene, 1-heptene or 1-octene, and more preferably, propylene, 1-butene, 1-hexene or 1-octene, and even more preferably 1-butene, 1-hexene or 1- octene. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α- olefin copolymer. In one embodiment, the ethylene/α-olefin interpolymer has a molecular weight distribution (M_w/M_n) less than, or equal to, 8, preferably less than, or equal to, 7, and more preferably less than, or equal to, 6. In another embodiment, the ethylene/α- olefin interpolymer has a molecular weight distribution (M_w/M_n) greater than, or equal to, 1.1, preferably greater than, or equal to, 1.2, and more preferably greater than, or equal to, 1.5. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, ethylene/α-olefin polymers have a molecular weight distribution from 1.1 to 5, and preferably from 1.5 to 4.5, and more preferably from 2 to 4. All individual values and subranges from 1.1 to 5 are included herein and disclosed herein. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, the ethylene/α-olefin interpolymer has a melt index (I₂) less than, or equal to, 1000 g/10 min, preferably less than, or equal to 500 g/10 min, and more preferably less than, or equal to 100 g/10 min. In another embodiment, the ethylene/α-olefin interpolymer has a melt index (I₂) greater than, or equal to, 0.01 g/10 min, preferably greater than, or equal to 0.1 g/10 min, and more preferably greater than, or equal to 1 g/10 min. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer. In another embodiment, the ethylene/α-olefin interpolymer has a melt index

(I₂) from 0.05 g/10 min to 300 g/10 min, preferably from 0.1 g/10 min to 200 g/10 min, and more preferably from 0.2 g/10 min to 60 g/10 min, and even more preferably from 0.5 g/10 min to 30 g/10 min, as determined using ASTM D-1238-04 (19O⁰C, 2.16 kg load). All individual values and subranges from 0.05 g/10 min to 300 g/10 min are included herein and disclosed herein. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, the ethylene/α-olefin interpolymer has a percent crystallinity of less than, or equal to, 60 percent, preferably less than, or equal to, 50 percent, and more preferably less than, or equal to, 40 percent, as measured by DSC. Preferably, these polymers have a percent crystallinity from 2 percent to 60 percent, including all individual values and subranges from 2 percent to 60 percent. Such individual values and subranges are disclosed herein. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, the ethylene/α-olefin interpolymer has a density less than, or equal to, 0.96 g/cc, preferably less than, or equal to, 0.95 g/cc, and more preferably less than, or equal to, 0.93 g/cc, and even more preferably less than, or equal to, 0.93 g/cc. In another embodiment, the ethylene/α-olefin interpolymer has a density greater than, or equal to, 0.85 g/cc, preferably greater than, or equal to, 0.86 g/cc, and more preferably greater than, or equal to, 0.87 g/cc. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer. In another embodiment, the ethylene/α-olefin interpolymer has a density from

0.85 g/cm³ to 0.93 g/cm³, and preferably from 0.86 g/cm³ to 0.92 g/cm³, and more preferably from 0.87 g/cm³ to 0.91 g/cm³. All individual values and subranges from 0.85 g/cm³ to 0.93 g/cm³ are included herein and disclosed herein. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer. In another embodiment, the ethylene/α-olefin interpolymer has a melt index

(I₂) less than, or equal to, 4 g/10 min, preferably less than, or equal to 3 g/10 min, and more preferably less than, or equal to 2 g/10 min. In another embodiment, the ethylene/α-olefin interpolymer has a melt index (I₂) greater than, or equal to, 0.01 g/10 min, preferably greater than, or equal to 0.05 g/10 min, and more preferably greater than, or equal to 0.1 g/10 min. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, the ethylene/α-olefin interpolymer has a melt index (I₂) from 0.01 g/10 min to 4 g/10 min, preferably from 0.05 g/10 min to 3 g/10 min, and more preferably from 0.1 g/10 min to 2 g/10 min, as determined using ASTM D- 1238-04 (19O⁰C, 2.16 kg load). AU individual values and subranges from 0.01 g/10 min to 4 g/10 min are included herein and disclosed herein. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, the ethylene/α-olefin interpolymer has a density less than, or equal to, 0.92 g/cc, and preferably less than, or equal to, 0.91 g/cc. In another embodiment, the ethylene/α-olefin interpolymer has a density greater than, or equal to, 0.87 g/cc, preferably greater than, or equal to, 0.88 g/cc. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

In another embodiment, the ethylene/α-olefin interpolymer has a density from 0.87 g/cm³ to 0.92 g/cm³, and preferably from 0.88 g/cm³ to 0.91 g/cm³. AU individual values and subranges from 0.87 g/cm³ to 0.92 g/cm³ are included herein and disclosed herein. In a further embodiment, the ethylene/α-olefin interpolymer is an ethylene/α-olefin copolymer.

An ethylene-base polymer may have a combination of two or more suitable embodiments as described herein. An ethylene/α-olefin interpolymer may have a combination of two or more suitable embodiments as described herein.

An ethylene/α-olefin copolymer may have a combination of two or more suitable embodiments as described herein.

Examples of propylene-based polymers useful in the present invention include propylene homopolymers and interpolymers of propylene with ethylene or another unsaturated comonomer. Interpolymers also include copolymer, terpolymers, tetrapolymers, and the like. Typically, the polypropylene interpolymers comprise units derived from propylene in an amount of at least about 60 weight percent (based on total weight of polymerizable monomers). Preferably, the propylene monomer is at least about 70 weight percent of the interpolymer, more preferably at least about 80 weight percent (based on total weight of polymerizable monomers).

The propylene interpolymers of interest include propylene/ethylene, propylene/1 -butene, propylene/1 -hexene, propylene/4-methyl-l-pentene, propylene/1 - octene, propylene/ethylene/1 -butene, propylene/ethylene/ENB, propylene/ethylene/1 - hexene, and propylene/ethylene/1 -octene, and more preferably, propylene/ethylene copolymers.

Suitable polypropylenes are formed, by means within the skill in the art, and include, for example, the use of single site catalysts (metallocene or constrained geometry) or Ziegler Natta catalysts. The propylene and optional comonomers, such as ethylene or alpha-olefin comonomers, are polymerized under conditions within the skill in the art, for instance, as disclosed by Galli, et al., Angew. Macromol. Chem., Vol. 120, 73 (1984), or by E.P. Moore, et al. in Polypropylene Handbook, Hanser Publishers, New York, 1996, particularly pages 11-98. Polypropylene polymers include, but are not limited to, Shell's KF 6100 homopolymer polypropylene; Solvay's KS 4005 polypropylene copolymer; Solvay's KS 300 polypropylene terpolymer; INSIRE™ polypropylene polymers available from The Dow Chemical Company; and VERSIFY™ polymers available from The Dow Chemical Company.

Propylene/α-olefin interpolymers or propylene/ethylene interpolymers, containing at least 50 mole percent polymerized propylene, include VERSIFY™ polymers (The Dow Chemical Company) and VISTAMAXX™ polymers (ExxonMobil Chemical Co.), LICOCENE™ polymers (Clariant), EASTOFLEX™ polymers (Eastman Chemical Co.), REXTAC™ polymers (Hunstman), and VESTOPLAST™ polymers (Degussa).

In another embodiment, the propylene-based polymer is a propylene/α-olefin interpolymer, which has a molecular weight distribution (M_w/M_n) less than, or equal to, 8, and preferably less than, or equal to, 7, and more preferably less than, or equal to 6. In another embodiment, the propylene-based polymer is a propylene/α-olefin interpolymer, which has a molecular weight distribution greater than, or equal to, 1.2, and preferably greater than, or equal to, 1.5, and more preferably greater than, or equal to 2. In another embodiment, the propylene/α-olefin interpolymer has a molecular weight distribution (M_w/M_n) from 1.5 to 8, and more preferably from 2 to 7, and more preferably from 2.5 to 6. All individual values and subranges from 1.5 to 8 are included herein and disclosed herein.

In another embodiment, the propylene/α-olefin interpolymer has a melt flow rate (MFR) less than, or equal to, 1000 g/10 min, preferably less than, or equal to, 500 g/10 min, and more preferably less than, or equal to, 100 g/10 min, and even more preferably less than, or equal to, 50 g/10 min, as measured in accordance with ASTM D 1238-04 at 230°C/2.16 kg. In another embodiment, propylene/α-olefin interpolymer has a melt flow rate (MFR) greater than, or equal to, 0.01 g/10 min, preferably greater than, or equal to, 0.1 g/10 min, and more preferably greater than, or equal to, 1 g/10 min, as measured in accordance with ASTM D 1238-04 at 230°C/2.16 kg.

In another embodiment, the propylene/α-olefin interpolymer has a melt flow rate (MFR) in the range of 0.01 to 1000 grams/10 minutes, preferably in range of 0.01 to 500 grams/10 minutes, more preferably from 0.1 to 100 grams/10 min, and even more preferably from 0.1 to 50 grams/10 min, as measured in accordance with ASTM D 1238-04 at 230°C/2.16 kg. AU individual values and subranges from 0.01 to 1000 grams/10 min are included herein and disclosed herein.

In another embodiment, the propylene/α-olefin interpolymer has a density less than, or equal to, 0.90 g/cc, preferably less than, or equal to, 0.89 g/cc, and more preferably less than, or equal to, 0.88 g/cc. In another embodiment, the propylene/α- olefin interpolymer has a density greater than, or equal to, 0.83 g/cc, preferably greater than, or equal to, 0.84 g/cc, and more preferably greater than, or equal to, 0.85 g/cc. In another embodiment, the propylene/α-olefin interpolymer has a density from 0.83 g/cm³ to 0.90 g/cm³, and preferably from 0.84 g/cm³ to 0.89 g/cm³, and more preferably from 0.85 g/cm³ to 0.88 g/cm³. All individual values and subranges from 0.83 g/cm³ to 0.90 g/cm³, are included herein and disclosed herein.

In another embodiment, the propylene-based polymer is a propylene/ethylene interpolymer, which has a molecular weight distribution less than, or equal to, 6, and preferably less than, or equal to, 5.5, and more preferably less than, or equal to 5. In another embodiment, the propylene-based polymer is a propylene/ethylene interpolymer, which has a molecular weight distribution greater than, or equal to, 1.2, and preferably greater than, or equal to, 1.5, and more preferably greater than, or equal to 2. In a preferred embodiment, the propylene/ethylene interpolymer is a propylene/ethylene copolymer.

In another embodiment, the propylene/ethylene interpolymer has a molecular weight distribution from 1.5 to 5, and more preferably from 2 to 4, and more preferably from 2.5 to 3. All individual values and subranges from 1.5 to 5 are included herein and disclosed herein. In a preferred embodiment, the propylene/ethylene interpolymer is a propylene/ethylene copolymer. In another embodiment, the propylene/ethylene interpolymer has a melt flow rate (MFR) less than, or equal to, 1000 g/10 min, preferably less than, or equal to, 500 g/10 min, and more preferably less than, or equal to, 100 g/10 min, and even more preferably less than, or equal to, 50 g/10 min, as measured in accordance with ASTM D 1238-04 at 230°C/2.16 kg. In another embodiment, propylene/ethylene interpolymer has a melt flow rate (MFR) greater than, or equal to, 0.01 g/10 min, preferably greater than, or equal to, 0.1 g/10 min, and more preferably greater than, or equal to, 1 g/10 min, as measured in accordance with ASTM D 1238-04 at 230°C/2.16 kg. In a preferred embodiment, the propylene/ethylene interpolymer is a propylene/ethylene copolymer.

In another embodiment, the propylene/ethylene interpolymer has a melt flow rate (MFR) in the range of 0.01 to 1000 grams/10 minutes, more preferably in range of 0.01 to 500 grams/10 minutes, more preferably from 0.1 to 100 grams/10 min, and even more preferably from 0.1 to 50 grams/10 min, as measured in accordance with ASTM D 1238-04 at 230°C/2.16 kg. AU individual values and subranges from 0.01 to 1000 grams/10 min are included herein and disclosed herein. In a preferred embodiment, the propylene/ethylene interpolymer is a propylene/ethylene copolymer. In another embodiment, the propylene/ethylene interpolymer has a density less than, or equal to, 0.90 g/cc, preferably less than, or equal to, 0.89 g/cc, and more preferably less than, or equal to, 0.88 g/cc. In another embodiment, the propylene/ ethylene interpolymer has a density greater than, or equal to, 0.83 g/cc, preferably greater than, or equal to, 0.84 g/cc, and more preferably greater than, or equal to, 0.85 g/cc. In a preferred embodiment, the propylene/ethylene interpolymer is a propylene/ethylene copolymer. In another embodiment, the propylene/ethylene interpolymer has a density from 0.83 g/cm³ to 0.90 g/cm³, and preferably from 0.84 g/cm³ to 0.89 g/cm³, and more preferably from 0.85 g/cm³ to 0.88 g/cm³. All individual values and subranges from 0.83 g/cm³ to 0.90 g/cm³, are included herein and disclosed herein. In a preferred embodiment, the propylene/ethylene interpolymer is a propylene/ethylene copolymer. In one embodiment, the propylene/α-olefin interpolymers or propylene/ethylene interpolymers are made using a metal-centered, heteroaryl ligand catalyst in combination with one or more activators, e.g., an arumoxane. In certain embodiments, the metal is one or more of hafnium and zirconium. More specifically, in certain embodiments of the catalyst, the use of a hafnium metal has been found to be preferred as compared to a zirconium metal for heteroaryl ligand catalysts. The catalysts in certain embodiments are compositions comprising the ligand and metal precursor, and, optionally, may additionally include an activator, combination of activators or activator package. Preferably the propylene-based polymer is a propylene/ethylene interpolymer.

The catalysts used to make the propylene/α-olefin interpolymers or propylene/ethylene interpolymers may additionally include catalysts comprising ancillary ligand-hafnium complexes, ancillary ligand- zirconium complexes and optionally activators, which catalyze polymerization and copolymerization reactions, particularly with monomers that are olefins, diolefins or other unsaturated compounds. Zirconium complexes, hafnium complexes, and similar compositions can be used. The metal-ligand complexes may be in a neutral or charged state. The ligand to metal ratio may also vary, the exact ratio being dependent on the nature of the ligand and metal-ligand complex. The metal-ligand complex or complexes may take different forms, for example, they may be monomeric, dimeric, or of an even higher order. Suitable catalyst structures and associated ligands are described in U.S. Patent 6,919,407, column 16, line 6, to column 41, line 23, which is incorporated herein by reference. In a further embodiment, the propylene/ethylene interpolymer comprises at least 50 weight percent propylene (based on the total amount of polymerizable monomers) and at least 5 weight percent ethylene (based on the total amount of polymerizable monomer), and has ¹³C NMR peaks, corresponding to a region error, at about 14.6 and 15.7 ppm, and the peaks are of about equal intensity (for example, see U.S. Patent 6,919,407, column 12, line 64 to column 15, line 51, incorporated herein by reference). The propylene/α-olefin interpolymers and the propylene/ethylene interpolymers can be made by any convenient process. In one embodiment, the process reagents, that is, (i) propylene, (ii) ethylene and/or one or more unsaturated comonomers, (iii) catalyst, and, (iv) optionally, solvent and/or a molecular weight regulator (for example, hydrogen), are fed to a single reaction vessel of any suitable design, for example, stirred tank, loop, or fluidized-bed. The process reagents are contacted within the reaction vessel under appropriate conditions (for example, solution, slurry, gas phase, suspension, high pressure) to form the desired polymer, and then the output of the reactor is recovered for post-reaction processing. All of the output from the reactor can be recovered at one time (as in the case of a single pass or batch reactor), or it can be recovered in the form of a bleed stream, which forms only a part, typically a minor part, of the reaction mass (as in the case of a continuous process reactor, in which an output stream is bled from the reactor, at the same rate at which reagents are added, to maintain the polymerization at steady- state conditions). "Reaction mass" means the contents within a reactor, typically during, or subsequent to, polymerization. The reaction mass includes reactants, solvent (if any), catalyst, and products and by-products. The recovered solvent and unreacted monomers can be recycled back to the reaction vessel. Suitable polymerization conditions are described in U.S. Patent 6,919,407, column 41, line 23 to column 45, line 43, incorporated herein by reference.

A propylene-based polymer may have a combination of two or more embodiments as described herein.

A propylene/α-olefin interpolymer may have a combination of two or more embodiments as described herein.

A propylene/ethylene interpolymer may have a combination of two or more embodiments as described herein. An olefin multi-block interpolymer may be used as a polyolefin of the invention. Olefin multi-block interpolymers may be made with two catalysts incorporating differing quantities of comonomer and a chain shuttling agent. Preferred olefin multi-block interpolymers are the ethylene/α-olefin multi-block interpolymers. An ethylene/α-olefin multi-block interpolymer has one or more of the following characteristics: (1) an average block index greater than zero and up to about 1.0 and a molecular weight distribution, Mw/Mn, greater than about 1.3; or

(2) at least one molecular fraction which elutes between 40⁰C and 130⁰C when fractionated using TREF, characterized in that the fraction has a block index of at least 0.5 and up to about 1; or

(3) an Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, wherein the numerical values of T_m and d correspond to the relationship:

T_m > -6553.3 + 13735(d) - 7051.7(d)²; or

(4) an Mw/Mn from about 1.7 to about 3.5, and is characterized by a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degrees Celsius defined as the temperature difference between the tallest DSC peak and the tallest CRYSTAF peak, wherein the numerical values of ΔT and ΔH have the following relationships:

ΔT > -0.1299(ΔH) + 62.81 for ΔH greater than zero and up to 130 J/g, ΔT > 48°C for ΔH greater than 130 J/g , wherein the CRYSTAF peak is determined using at least 5 percent of the cumulative polymer, and if less than 5 percent of the polymer has an identifiable CRYSTAF peak, then the CRYSTAF temperature is 30⁰C; or

(5) an elastic recovery, Re, in percent at 300 percent strain and 1 cycle measured with a compression-molded coated substrate of the ethylene/α-olefin interpolymer, and has a density, d, in grams/cubic centimeter, wherein the numerical values of Re and d satisfy the following relationship when ethylene/α-olefin interpolymer is substantially free of a cross-linked phase: Re >1481-1629(d); or

(6) a molecular fraction which elutes between 40⁰C and 130⁰C when fractionated using TREF, characterized in that the fraction has a molar comonomer content of at least 5 percent higher than that of a comparable random ethylene interpolymer fraction eluting between the same temperatures, wherein said comparable random ethylene interpolymer has the same comonomer(s) and has a melt index, density, and molar comonomer content (based on the whole polymer) within 10 percent of that of the ethylene/α-olefin interpolymer; or

(7) a storage modulus at 25 ⁰C, G'(25 ⁰C), and a storage modulus at 100 ⁰C, G' (100 ⁰C), wherein the ratio of G' (25 ⁰C) to G' (100 ⁰C) is in the range of about 1:1 to about 9:1.

In a further embodiment, the ethylene/α-olefin interpolymers are ethylene/ α- olefin copolymers made in a continuous, solution polymerization reactor, and which possess a most probable distribution of block lengths. In one embodiment, the copolymers contain 4 or more blocks or segments including terminal blocks. The ethylene/α-olefin multi-block interpolymers typically comprise ethylene and one or more copolymerizable α-olefin comonomers in polymerized form, characterized by multiple blocks or segments of two or more polymerized monomer units differing in chemical or physical properties. That is, the ethylene/α-olefin interpolymers are block interpolymers, preferably multi-block interpolymers or copolymers. In some embodiments, the multi-block copolymer can be represented by the following formula:

(AB)_n where n is at least 1, preferably an integer greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, "A" represents a hard block or segment and "B" represents a soft block or segment. Preferably, the As and Bs are linked in a substantially linear fashion, as opposed to a substantially branched or substantially star-shaped fashion. In other embodiments, A blocks and B blocks are randomly distributed along the polymer chain. In other words, the block copolymers usually do not have a structure as follows. AAA- AA-BBB- BB

In still other embodiments, the block copolymers do not usually have a third type of block, which comprises different comonomer(s). In yet other embodiments, each of block A and block B has monomers or comonomers substantially randomly distributed within the block. In other words, neither block A nor block B comprises two or more sub-segments (or sub-blocks) of distinct composition, such as a tip segment, which has a substantially different composition than the rest of the block. The ethylene multi-block polymers typically comprise various amounts of "hard" and "soft" segments. "Hard" segments refer to blocks of polymerized units in which ethylene is present in an amount greater than about 95 weight percent, and preferably greater than about 98 weight percent based on the weight of the polymer. In other words, the comonomer content (content of monomers other than ethylene) in the hard segments is less than about 5 weight percent, and preferably less than about 2 weight percent based on the weight of the polymer. In some embodiments, the hard segments comprise all or substantially all ethylene. "Soft" segments, on the other hand, refer to blocks of polymerized units in which the comonomer content (content of monomers other than ethylene) is greater than about 5 weight percent, preferably greater than about 8 weight percent, greater than about 10 weight percent, or greater than about 15 weight percent based on the weight of the polymer. In some embodiments, the comonomer content in the soft segments can be greater than about 20 weight percent, greater than about 25 weight percent, greater than about 30 weight percent, greater than about 35 weight percent, greater than about 40 weight percent, greater than about 45 weight percent, greater than about 50 weight percent, or greater than about 60 weight percent. The soft segments can often be present in a block interpolymer from about 1 weight percent to about 99 weight percent of the total weight of the block interpolymer, preferably from about 5 weight percent to about 95 weight percent, from about 10 weight percent to about 90 weight percent, from about 15 weight percent to about 85 weight percent, from about 20 weight percent to about 80 weight percent, from about 25 weight percent to about 75 weight percent, from about 30 weight percent to about 70 weight percent, from about 35 weight percent to about 65 weight percent, from about 40 weight percent to about 60 weight percent, or from about 45 weight percent to about 55 weight percent of the total weight of the block interpolymer. Conversely, the hard segments can be present in similar ranges. The soft segment weight percentage and the hard segment weight percentage can be calculated based on data obtained from DSC or NMR. Such methods and calculations are disclosed in a concurrently filed U.S. Patent Application Serial No. 11/376,835 (insert when known), Attorney Docket No. 385063-999558, entitled "Ethylene/α- Olefin Block Interpolymers", filed on March 15, 2006, in the name of Colin L.P. Shan, Lonnie Hazlitt, et. al. and assigned to Dow Global Technologies Inc., the disclosure of which is incorporated by reference herein in its entirety.

The term "multi-block copolymer" or "segmented copolymer" refers to a polymer comprising two or more chemically distinct regions or segments (referred to as "blocks") preferably joined in a linear manner, that is, a polymer comprising chemically differentiated units which are joined end-to-end with respect to polymerized ethylenic functionality, rather than in pendent or grafted fashion. In a preferred embodiment, the blocks differ in the amount or type of comonomer incorporated therein, the density, the amount of crystallinity, the crystallite size attributable to a polymer of such composition, the type or degree of tacticity (isotactic or syndiotactic), regio-regularity or regio-irregularity, the amount of branching, including long chain branching or hyper-branching, the homogeneity, or any other chemical or physical property. The multi-block copolymers are characterized by unique distributions of both polydispersity index (PDI or M_w/M_n), block length distribution, and/or block number distribution due to the unique process making of the copolymers. More specifically, when produced in a continuous process, the polymers desirably possess PDI from 1.7 to 2.9, preferably from 1.8 to 2.5, more preferably from 1.8 to 2.2, and most preferably from 1.8 to 2.1. When produced in a batch or semi-batch process, the polymers possess PDI from 1.0 to 2.9, preferably from 1.3 to 2.5, more preferably from 1.4 to 2.0, and most preferably from 1.4 to 1.8.

In one embodiment, an ethylene/α-olefin multi-block interpolymer has an ethylene content of from 60 to 90 percent, a diene content of from 0 to 10 percent, and an α-olefin content of from 10 to 40 percent, based on the total weight of the polymer. In one embodiment, such polymers are high molecular weight polymers, having a weight average molecular weight (M_w) from 10,000 to about 2,500,000, preferably from 20,000 to 500,000, more preferably from 20,000 to 350,000; a polydispersity less than 3.5, more preferably less than 3 and as low as about 2; and a Mooney viscosity of the neat polymer (no filler, no oil) (ML (1+4) at 125°C) from 1 to 250. Mooney viscosity is typically determined from a regression analysis for high viscosity polymers (ML (1+4) at 125°C typically greater than 100).

In one embodiment, the ethylene multi-block interpolymers have a density of less than about 0.90, preferably less than about 0.89, more preferably less than about 0.885, even more preferably less than about 0.88 and even more preferably less than about 0.875, g/cc. In one embodiment, the ethylene multi-block interpolymers have a density greater than about 0.85, and more preferably greater than about 0.86, g/cc. Density is measured by the procedure of ASTM D-792-00. Low density ethylene multi-block copolymers are generally characterized as amorphous, flexible, and have good optical properties, for example, high transmission of visible and UV-light and low haze.

In one embodiment, the ethylene multi-block interpolymers have a melting point of less than about 125°C. The melting point is measured by the differential scanning calorimetry (DSC) method described in U.S. Publication 2006/0199930 (WO 2005/090427), incorporated herein by reference.

In one embodiment, the ethylene/α-olefin multi-block interpolymer has a melt index (I₂) less than, or equal to, 40 g/10 min, preferably less than, or equal to 30 g/10 min, and more preferably less than, or equal to 20 g/10 min. In another embodiment, the ethylene/α-olefin multi-bock interpolymer has a melt index (I₂) greater than, or equal to, 0.05 g/10 min, preferably greater than, or equal to 0.1 g/10 min, and more preferably greater than, or equal to 1 g/10 min. In a further embodiment, the ethylene/α-olefin multi-block interpolymer is an ethylene/α-olefin multi-block copolymer.

In another embodiment, the ethylene/α-olefin multi-block interpolymer has a melt index (I₂) from 0.05 g/10 min to 40 g/10 min, preferably from 0.1 g/10 min to 30 g/10 min, and more preferably from 1 g/10 min to 20 g/10 min, as determined using ASTM D-1238-04 (19O⁰C, 2.16 kg load). AU individual values and subranges from 0.05 g/10 min to 40 g/10 min are included herein and disclosed herein. In a further embodiment, the ethylene/α-olefin multi-block interpolymer is an ethylene/α-olefin multi-block copolymer. In another embodiment, the ethylene/α-olefin multi-block interpolymer has a density less than, or equal to, 0.92 g/cc, and preferably less than, or equal to, 0.91 g/cc. In another embodiment, the ethylene/α-olefin multi-block interpolymer has a density greater than, or equal to, 0.86 g/cc, preferably greater than, or equal to, 0.87 g/cc. In a further embodiment, the ethylene/α-olefin multi-block interpolymer is an ethylene/α-olefin multi-block copolymer.

In another embodiment, the ethylene/α-olefin multi-block interpolymer has a density from 0.86 g/cm³ to 0.92 g/cm³, and preferably from 0.87 g/cm³ to 0.91 g/cm³. All individual values and subranges from 0.86 g/cm³ to 0.92 g/cm³ are included herein and disclosed herein. In a further embodiment, the ethylene/α-olefin multi- block interpolymer is an ethylene/α-olefin multi-block copolymer.

The ethylene multi-block interpolymers and their preparation and use, are more fully described in WO 2005/090427, US2006/0199931, US2006/0199930, US2006/0199914, US2006/0199912, US2006/0199911, US2006/0199910, US2006/0199908, US2006/0199907, US2006/0199906, US2006/0199905, US2006/0199897, US2006/0199896, US2006/0199887, US2006/0199884, US2006/0199872, US2006/0199744, US2006/0199030, US2006/0199006 and US2006/0199983; each publication is fully incorporated herein by reference.

An olefin multi-block interpolymer may comprise a combination of two or more embodiments as described herein.

An ethylene multi-block interpolymer may comprise a combination of two or more embodiments as described herein.

An ethylene/α-olefin multi-block interpolymer may comprise a combination of two or more embodiments as described herein.

Polyolefin Blends

In another embodiment of the invention, a blend of two of more polyolefins is subject to grafting, crosslinking and foaming reactions, such as a blend of two or more ethylene-base polymers, as discussed above; a blend of two or more propylene-base polymers, as discussed above; a blend of at least one ethylene-base polymer, as discussed above, and at least one propylene-based polymer, as discussed above; or combinations thereof. Additional blends include a blend of two or more olefin multi- block interpolymers, as discussed above; a blend of at least one ethylene-base polymer, as discussed above, and at least one olefin multi-block interpolymer, as discussed above; a blend of at least one propylene-base polymer, as discussed above, and at least one olefin multi-block interpolymer, as discussed above; a blend of at least one ethylene-base polymer, as discussed above, at least one propylene-based polymer, as discussed above, and at least one olefin multi-block interpolymer, as discussed above; or combinations thereof.

Grafting Compound

TEMPO compounds are suitable functionalization agents for use in the compositions of the invention, and are generally represented by compound (I) below:

(I).

In structure (I), R¹ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched. In a preferred embodiment, R¹ is either hydrogen, or a Cl-ClO, preferably a C1-C8, and more preferably a C1-C6, hydrocarbyl radical, which is linear or branched. In one embodiment, R¹ is a methyl group. In another embodiment, R¹ is hydrogen. In another embodiment, R¹ is an ethyl group. R² is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched. In a preferred embodiment, R is either hydrogen, or a Cl-ClO, preferably a C1-C8, and more preferably a C1-C6, hydrocarbyl radical, which is linear or branched. In one embodiment, R is a methyl group. In another embodiment, R is hydrogen. In another embodiment, R is an ethyl group. R³ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched. In a preferred embodiment, R³ is either hydrogen, or a Cl-ClO, preferably a C1-C8, and more preferably a C1-C6, hydrocarbyl radical, which is linear or branched. In one embodiment, R³ is a methyl group. In another embodiment, R³ is hydrogen. In another embodiment, R³ is an ethyl group.

R⁴ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched. In a preferred embodiment, R⁴ is either hydrogen, or a Cl-ClO, preferably a C1-C8, and more preferably a C1-C6, hydrocarbyl radical, which is linear or branched. In one embodiment, R⁴ is a methyl group. In another embodiment, R⁴ is hydrogen. In another embodiment, R⁴ is an ethyl group.

In structure (I), Z is either OH, SH, NH₂ or NHR⁵, where R⁵ is a C1-C20 hydrocarbyl radical, which is linear or branched. In a preferred embodiment, R⁵ is either hydrogen, or a Cl-ClO, preferably a C1-C8, and more preferably a C1-C6, hydrocarbyl radical, which is linear or branched. In one embodiment, R⁵ is a methyl group. In another embodiment, R⁵ is hydrogen. In another embodiment, R⁵ is an ethyl group.

In one embodiment, each of Rl, R2, R3, and R4, is independently hydrogen, a methyl group, or an ethyl group.

In another embodiment, each of Rl, R2, R3, and R4, is independently hydrogen, or a methyl group.

In another embodiment, each of Rl, R2, R3, and R4, is a methyl group.

In another embodiment, each of Rl, R2, R3, and R4, is hydrogen.

Other compounds include, but are not limited to, 2,2,6,6- tetramethyl piperidinyl oxy (TEMPO) and its derivatives, bis-TEMPOs, oxo-TEMPO, an ester of 4-hydroxy-TEMPO, polymer-bound TEMPO, PROXYL, DOXYL, all-tertiary butyl N oxyl, dimethyl diphenylpyrrolidine-1-oxyl, 4 phosphonoxy TEMPO, or a metal complex with TEMPO. An example of a bis-TEMPO is bis(l-oxyl-2,2,6,6- tetramethylpiperidine-4 yl)sebacate. Each compound may be used as a grafting agent in a composition comprising a polyolefin, a blowing agent and an initiator. As discussed above, preferred compounds comprise a Z group capable of reaction with other chemical groups. For example, the 4-hydroxy TEMPO is a preferred compound.

The notation Cl-Cn, where n is 2, 3, 4, etc., and as used in reference to the R groups (R¹, R², R³, R⁴ and R⁵), refers to the range of carbon atoms that are included for each R group. For example, a C1-C20 hydrocarbyl radical refers to a hydrocarbon group containing 1 to 20 carbon atoms. Also, the range of carbon atoms (for example,

C1-C20) includes all individual values (for example, 1, 2, 3, 4, etc.) of the total number of carbon atoms, and includes all subranges (for example, C1-C8, C4-C12,

C10-C20, etc.) within the broadest range (for example, C1-C20) of carbon atoms specified. All individual values and subranges are included herein and disclosed herein.

In one embodiment, the Compound I is present in an amount greater than, or equal to, 0.05 phr, preferably greater than, or equal to, 0.10 phr, and more preferably greater than, or equal to, 0.15 phr, based on hundred parts of the polyolefin. In another embodiment, the Compound I is present in an amount less than, or equal to, 0.5 phr, preferably less than, or equal to, 0.3 phr, and more preferably less than, or equal to, 0.25 phr, and even more and more preferably less than, or equal to,

0.20 phr, based on hundred parts of the polyolefin.

In another embodiment, the Compound I is present in an amount from 0.05 phr to 0.25 phr, preferably from 0.05 to 0.20 phr, and more preferably from 0.05 to

0.15 phr, based on hundred parts of the polyolefin.

In another embodiment, the Compound I is present in an greater than, or equal to, 0.25 phr, and preferably greater than, or equal to, 0.50 phr, based on hundred parts of the polyolefin.

Grafting Reaction

A TEMPO compound, such as 4-hydroxy-2,2,6,6-tetramethyl-l- piperidinyloxy (4-hydroxy- TEMPO), or a derivative thereof, reacts preferentially with carbon center free radicals, which results in, for example, the 4-hydroxy- TEMPO moiety being grafted onto the polymer backbone, via the oxygen atom on the O-N functionality, leaving an hydroxyl group on the 4 position of the piperidinyloxy ring (see the schematic below). The active hydrogen of the hydroxyl group can react chemically with materials, such as isocyanate, to improve adhesion or paintability via chemical reaction with the OH group.

Grafted 4-hydroxy-TEMPO moiety

In processes, such as the creation of crosslinked foams, the foams are created in the presence of a peroxide, which generates peroxoyl free radicals leading to the formation of carbon free radicals on the polymer. The presence of a TEMPO compound under these conditions allows grafting of the TEMPO moiety to take place, when the compound is being transformed into a crosslinked foam, and does not require the polymer to be pre-grafted. Processes in addition to those used to form compression molded, crosslinked foams, can be adapted to take advantage of this in- situ functionalization. For example, the typical production of calendared polyolefin sheets allows for a heating step to decompose a chemical blowing agent, depending on whether foamed or unfoamed sheets are desired, and this same process can be used to simultaneously graft a TEMPO compound onto a polymer backbone, while crosslinking the polymer via peroxide. The resulting calendared sheet would have grafted moieties containing active hydrogens, which can further react with isocyanate groups to improve adhesion to paints and other substrates. The in-situ grafting can be applied to a polyolefin, which can form a carbon center free radical, and which undergoes a crosslinking reaction. The benefit of this method is that a separate polymer grafting step(s) is not required, and the resulting polymer contains active hydrogen, which can react with a Lewis base contained in an adhesive, paint, or other material, to improve adhesion and/or paintability. An amine-reactive group or hydroxyl-reactive group, for example, can be grafted to the polyolefin by any conventional method, typically in the presence of a free radical initiator, for example peroxides and azo initiators, thermal treatment, or by radiation. Organic initiators are preferred, such as any one of the peroxide initiators, for example, dicumyl peroxide, di-tert-butyl peroxide, t-butyl perbenzoate, benzoyl peroxide, cumene hydroperoxide, t-butyl peroctoate, methyl ethyl ketone peroxide, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane, lauryl peroxide, and tert-butyl peracetate, t-butyl α-cumyl peroxide, di-t-butyl peroxide, di-t-amyl peroxide, t-amyl peroxybenzoate, l,l-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, α,α'-bis(t- butylperoxy)- 1 ,3-diisopropylbenzene, α,α' -bis(t-butylperoxy)- 1 ,A- diisopropylbenzene, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, and 2,5-bis(t- butylperoxy)-2,5-dimethyl-3-hexyne. A suitable azo compound is azobisisobutyl nitrite.

The active hydrogen incorporated into the polyolefin can be hydroxyl, thiol, amino, or amine, and is preferably is hydroxyl. The most preferred active hydrogen is that of the 4-hydroxyl group on the 4-hydroxy-2,2,6,6-tetramethyl-l-piperidinyloxy moiety. The paint, coating, primer, or adhesive, each preferably contains a reactive species, such as isocyanate, silane, or any Lewis base. Such species may react with hydroxyl groups, thiol groups, amino groups, and amine groups. Polymeric isocyanate is a preferred reactive species.

A "0.1 phr TEMPO addition," based on hundred parts polyolefin, in the foam formulation, represents approximately one grafted hydroxyl group per 12000 carbon centers on the polymer, assuming a 100 percent grafting efficiency, based on the following calculation. A polyethylene polymer and an ethylene/alpha-olefin has same approximate generic formulation in terms of CH2 units. The moles of active carbon centres on an ethylene/alpha-olefin interpolymer can be approximated by using the formula (CH2)n, which for lOOg of polymer, equates to 7.1 moles of CH2 units (14 g/mol). Therefore, 0.1 g of hydroxyl-TEMPO in lOOg of polymer is equivalent to the presence of 0.008 mol of Z-group in 1 mol of carbon centres.

The 4-hyroxy- TEMPO (with molecular weight 172 g/mol) in an amount of 0.1 g, contains 0.00058 moles of 4-hydroxy-TEMPO molecules ("0.00058 moles TEMPO per 7.1 mole CH2," or "0.000082 mole TEMPO per 1 mole CH2"), and the calculated "CH2 carbon centre to 4-hydroxy-TEMPO" mole ratio is approximately "12000 to 1." Therefore, if every molecule of 4-hydroxy- TEMPO reacts with a carbon free radical on the polymer, this results in a successful graft, and one hydroxyl group (from the A- hydroxy- TEMPO) would be present for every 12000 carbon centers on the polymer.

Other grafting reactions using 2,2,6,6-tetramethyl-l-piperidinyloxy (the TEMPO compound without the 4-hydroxy functionality), in the presence of dicumylperoxide, show a grafting efficiency greater than 50 percent, which indicates that there is one grafted TEMPO compound present for about every 24000 carbon centers. At these grafting levels, improvements in adhesion are already observed. The grafting of 4-hydroxy- TEMPO is believed to behave similarly to the non-hydroxy analogue. Since the TEMPO compound can react with available carbon centre free radicals, on a polymer, or with lower molecular weight species, such as the methyl radical generated in dicumylperoxide systems, a grafting efficiency of 100 percent is typically not expected. Grafting efficiency can be determined by 13C NMR as described herein. Grafting in the presence of dicumylperoxide showed a 57 percent efficiency, which is slightly higher than one half, and which was shown to be sufficient to improve adhesion in the present invention. From a practical perspective, a 25 percent grafting efficiency can still be used to improved adhesion.

Initiators

The preferred initiators are organic peroxides, such as dicumylperoxide and di(tert-butylperoxyisopropyl)benzene. The free radical generation can be initiated via chemical, thermal or radiation methods.

Preferably, the peroxide is present in an amount from about 0.1 to about 10 phr (parts per hundred parts of polyolefin by weight), more preferably, from about 0.5 to about 5.0 phr, and even more preferably, from about 0.6 to about 1.5 phr, or from 0.6 to 1.3 phr.

The grafting reaction should be performed under conditions that maximize grafts onto the polyolefin backbone, and minimize side reactions. The grafting reaction may be performed in the melt, in solution, in the solid-state, in a swollen- state, and is preferably performed in the melt. Mixing the resin with the grafting agent and initiator in the first stage of an extruder, at melt temperatures typically from 12O⁰C to 26O⁰C, preferably from 13O⁰C to 25O⁰C, has produced sufficiently grafted polymers. All individual temperature values and ranges from 12O⁰C to 26O⁰C are included herein and disclosed herein.

Crosslinking Reaction

In the absence of TEMPO, the crosslinking of hydrocarbon polymers, effected by free radicals, is well-known. Figure 1 depicts the typical crosslinking mechanism effected by dicumylperoxide. The "Z group" is not shown below; however, it is understood that such group can be present, without altering the general reaction scheme as shown in Figure 1, when the peroxide is used in excess (relative to the TEMPO compound).

In the presence of a TEMPO compound, grafting typically takes place according to the mechanism depicted in Figure 2. In Figure 2, the Z group on the TEMPO compound is hydroxyl. As soon as a carbon free radical is generated (Species A or B), TEMPO reacts at that location. Only reaction of TEMPO with "Species A" results in the grafting onto the polymer backbone to produce "grafted- polymer." When peroxide is in excess of TEMPO, all the TEMPO is ultimately consumed by reacting with carbon centre radicals, and crosslinking resumes as depicted in Figure 1.

To obtain optimum utility of the TEMPO, in an in-situ grafting manner, while retaining the benefit of foam homogeneity, as well as other property benefits, a preferred excess amount of peroxide exists, relative to the amount of TEMPO.

In a preferred embodiment, the peroxoyl radical/TEMPO molar ratio is from 2.5 to 40, preferably from 4 to 35, and more preferably from 6 to 30. In another embodiment, the molar ratio is from 6 to 20, preferably from 6 to 15.

In another embodiment, the peroxoyl radical content is from 6.5 to 20, relative to a base of 10,000 moles of carbon centers for the polyolefin. This is calculated from the following basis, that each peroxide molecule, and preferably a dicumylperoxide molecule, which has a molecular weight of 270 g/mol, generates two of peroxoyl radicals, and is assumed to be 100 percent effective in generating the cumylperoxoyl radicals.

The polymeric composition may also contain catalysts for increasing free- radical formation. Suitable examples of catalysts include tertiary amines, cobalt naphthenate, manganese naphthenate, vanadium pentoxide, and quaternary ammonium salt.

Foaming Reaction

Chemical foaming can be used in the manufacturing of peroxide crosslinked foams, such as those used in shoe soles. While the polymer is being crosslinked, under heat, in a closed mold, the foaming agent decomposes at about the same time to release gases, such as nitrogen and/or carbon dioxide. Since the reaction is under a closed mold, the gases are trapped within the polymer under pressure. When the crosslinking reaction is complete, the mold opens, and with the instantaneous removal of the mold pressure, the gases expand rapidly, resulting in the expansion of the cured polymer into a foam structure.

The heating process is typically effected by heat sources applied to the ends of the mold. As such, a thermal gradient exists, which causes the core of the article furthest from the heat sources, at either end, to arrive at the curing temperature at a slower rate, and therefore, the core is relatively under cured compared to the article's surfaces. It is well-known in the industry that foam articles, commonly having cross- section thicknesses around 0.5 cm to 5 cm, have differences in hardness, from the surface of the foam to the core of the foam in Shore A units of 9-11, or greater, due to the thermal gradient across the thickness cross-section of the article. The TEMPO compound also acts as a scorch suppressant, and reduces the curing inhomogeneity in the curing process between the surface and the core. Foams created in the presence of TEMPO have skin and core hardness differences of about 5 Shore A units.

An example of practical application, which benefits from the improved homogeneity in foam hardness, is of the use of slabs of stock foams, which can be as thick as 5 cm or more, for foam articles, such as footwear soles. Since footwear soles have hardness specifications, and conventional slabs have significant variations in hardness along the cross-sections of the slabs, industry practitioners cannot use the same slab of foam, in its entirety, to fabricate the same products. Practitioners are forced to select different cross-sections on a slab, and match them to different end product specifications. This approach increases wastes, and reduces the efficiency of the slab stock. With a reduced core to surface hardness differential, the same slab of foam can be fully utilized for the same product specification.

Blowing Agents

The blowing agent can be a chemical or a physical blowing agent. Preferably, the blowing agent will be a chemical blowing agent. Examples of a useful chemical blowing agents include, but are not limited to, azodicarbonamide and azobisforamide.

More preferably, the blowing agent will be a chemical blowing agent, having its activation temperature within the nominal crosslinking temperature profile.

Preferably, when the blowing agent is a chemical blowing agent, it is present in an amount between about 0.05 to about 10.0 phr, based on the amount of polyolefin. More preferably, it is present between about 0.5 to about 5.0 phr, even more preferably, between about 1.5 to about 4.0 phr.

Other Additives Additives useful with polymeric compositions of the present invention include, but are not limited to, curing coagents, scorch inhibitors, antioxidants, fillers, clays, processing aids, carbon black, flame retardants, peroxides, dispersion agents, waxes, coupling agents, mold release agents, light stabilizers, metal deactivators, plasticizers, antistatic agents, whitening agents, nucleating agents, other polymers, and colorants. The crosslinkable, expandable polymeric compositions can be highly filled.

Suitable non-halogenated flame retardant additives include alumina trihydrate, magnesium hydroxide, red phosphorus, silica, alumina, titanium oxides, melamine, calcium hexaborate, alumina, carbon nanotubes, wollastonite, mica, silicone polymers, phosphate esters, hindered amine stabilizers, ammonium octamolybdate, intumescent compounds, melamine octamolybdate, frits, hollow glass microspheres, talc, clay, organo-modified clay, zinc borate, antimony trioxide, and expandable graphite. Suitable halogenated flame retardant additives include decabromodiphenyl oxide, decabromodiphenyl ethane, ethylene-big (tetrabromophthalimide), and dechlorane plus. Typically, polymers and resins used in the invention are treated with one or more stabilizers, for example, antioxidants, such as Irganox™ 1010 and Irgafos™ 168, both supplied by Ciba Specialty Chemicals. Polymers are typically treated with one or more stabilizers before an extrusion or other melt processes. Other polymeric additives include, but are not limited to, ultraviolet light absorbers, antistatic agents, pigments, dyes, nucleating agents, fillers slip agents, fire retardants, plasticizers, processing aids, lubricants, stabilizers, smoke inhibitors, viscosity control agents and anti-blocking agents.

Applications The crosslinked polymers of the invention can be used in various applications, including, but not limited to foam substrates, footwear components, injection molded articles, roofing and construction materials and artificial turf.

In particular, the inventive crosslinked foams can be used in the following applications: (a) outsoles, midsoles and stiffners, to be assembled with standard polyurethane adhesive systems currently used by footwear industry, (b) painting of soles and mid-soles with polyurethane paints, currently used by footwear industry, and (c) over-molding of polyolefins and bi-component polyurethanes for multilayered soles and midsoles. In addition, polyolefin/polyurethane blends can be used in other applications, such as automotive applications and construction applications. Automotive applications include, but are not limited to, the manufacture of bumper fascias, vertical panels, soft TPO skins, interior trim. Construction applications include, but are not limited to, the manufacture of furniture and toys.

Additional applications include adhesion of co-extruded films, where one or more substrates are compatible or reactive with hydroxyl groups, and the lamination of polyolefin based films to other polar substrates (for example, glass lamination).

Further applications include artificial leather to be adhered to polar substrates, such as polyurethane, polyvinyl chloride (PVC), and others. Artificial leather is used for automotive interiors adhering to polyurethane for seating, head liners.

The crosslinked foams are also suitable for Health & Hygiene products, such as wipes and cleaning tissues. The crosslinked foams can be used to enhance hydrophilicity of the polyolefin for novel membrane structures for separation or breathability. The crosslinked foams are also suitable for use as self-adhearable polymers onto metal or textile structures for automotive. As discussed above, the crosslinked foams are well suited for blends and compatibilizers with enhanced interaction towards polar polymers, such as TPU, EVA, PVC, PC, PET, PBT. Such bends can be used for novel compounds for footwear, automotive, consumer, durables, appliances, electronic housing, apparel, and conveyor belts. The crosslinked foams can also serve as compatibilizers between natural fibers and other polyolefins for use in applications, such as wood binding formulations or cellulose binding formulations. The crosslinked foams of the invention are also useful in blends with one or more polyether block amides, such as Pebax® polymers available from Arkema.

The crosslinked foams can also be used to enhance the interaction to fillers, such as silica, carbon black or clay, for use in formulations for toners, tires, coatings or other compounds. Among other applications, the present invention is particularly useful in footwear, automotive, furniture, carpet and construction applications. The particularly useful articles of manufacture made from the present invention include shoe soles, multicomponent shoe soles (including polymers of different densities and types), weather stripping, gaskets, profiles, durable goods, run flat tire inserts, construction panels, leisure and sports equipment foams, energy management foams, acoustic management foams, insulation foams, and other foams.

Various processes can be used to form an inventive article. Useful processes include, but are not limited to, injection molding, extrusion, compression molding, rotational molding, thermoforming, blow molding, powder coating, fiber spinning and calendaring. Polymer compositions may be mixed in a variety of apparatuses, including, but not limited to, a batch mixer, a Brabender mixer, a Busch mixer, a Farrel mixer, or an extruder.

DEFINITIONS Any numerical range recited herein, includes all values from the lower value to the upper value, in increments of one unit, provided that there is a separation of at least two units between any lower value and any higher value. As an example, if it is stated that a compositional, physical or mechanical property, such as, for example, molecular weight, viscosity, melt index, etc., is from 100 to 1,000, it is intended that all individual values, such as 100, 101, 102, etc., and sub ranges, such as 100 to 144, 155 to 170, 197 to 200, etc., are expressly enumerated in this specification. For ranges containing values which are less than one, or containing fractional numbers greater than one (for example, 1.1, 1.5, etc.), one unit is considered to be 0.0001, 0.001, 0.01 or 0.1, as appropriate. For ranges containing numbers less than ten (for example, 1 to 5), one unit is typically considered to be 0.1. These are only examples of what is specifically intended, and all possible combinations of numerical values between the lowest value and the highest value enumerated, are to be considered to be expressly stated in this application. Numerical ranges have been recited, as discussed herein, in reference to melt index, melt flow rate, molecular weight distribution, density and other properties.

The term "composition," as used herein, includes a mixture of materials which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

The terms "blend" or "polymer blend," as used herein, mean a blend of two or more polymers. Such a blend may or may not be miscible (not phase separated at molecular level). Such a blend may or may not be phase separated. Such a blend may or may not contain one or more domain configurations, as determined from transmission electron spectroscopy, light scattering, x-ray scattering, and other methods known in the art. The term "polymer," as used herein, refers to a polymeric compound prepared by polymerizing monomers whether of the same or a different type. The generic term polymer thus embraces the term homopolymer, usually employed to refer to polymers prepared from only one type of monomer, and the term interpolymer as defined hereinafter. The terms "ethylene/α-olefin polymer" and "propylene/α-olefin polymer" are indicative of interpolymers as described below. As is known in the art, monomers are present in the polymer in polymerized forms.

The term "interpolymer," as used herein, refers to polymers prepared by the polymerization of at least two different types of monomers. The generic term interpolymer thus includes copolymers, usually employed to refer to polymers prepared from two different monomers, and polymers prepared from more than two different types of monomers.

The term, "ethylene-based polymer," as used herein, refers to a polymer that comprises more than 50 mole percent or a majority molar amount of polymerized ethylene monomer (based on the total amount of polymerizable monomers), and optionally may comprise at least one comonomer. The term, "ethylene/α-olefin interpolymer," as used herein, refers to an interpolymer that comprises more than 50 mole percent or a majority molar amount of polymerized ethylene monomer (based on the total amount of polymerizable monomers), and at least one α-olefin. As used in the context of this disclosure, ethylene/α-olefin interpolymer excludes ethylene/α-olefin multi-block interpolymers. The term, "ethylene/α-olefin copolymer," as used herein, refers to a copolymer that has polymerized therein more than 50 mole percent ethylene (based on the total amount of polymerizable monomers), and an α-olefin. As used in the context of this disclosure, ethylene/α-olefin copolymer excludes ethylene/α-olefin multi-block copolymers. The term, "propylene-based polymer," as used herein, refers to a polymer that comprises more than 50 mole percent or a majority molar amount of polymerized propylene monomer (based on the total amount of polymerizable monomers), and optionally may comprise at least one comonomer.

The term, "propylene/α-olefin interpolymer," as used herein, refers to an interpolymer that comprises more than 50 mole percent or a majority molar amount of polymerized propylene monomer (based on the total amount of polymerizable monomers), and at least one α-olefin. As used in the context of this disclosure, propylene/α-olefin interpolymer excludes propylene/α-olefin multi-block interpolymers.

The term, "propylene/ethylene interpolymer," as used herein, refers to an interpolymer that comprises more than 50 mole percent or a majority molar amount of polymerized propylene monomer (based on the total amount of polymerizable monomers), ethylene, and, optionally, at least one comonomer. As used in the context of this disclosure, propylene/ethylene interpolymer excludes propylene/ethylene multi-block interpolymers. The term, "propylene/ethylene copolymer," as used herein, refers to a copolymer that has polymerized therein more than 50 mole percent propylene (based on the total amount of polymerizable monomers), and ethylene. As used in the context of this disclosure, propylene/ethylene copolymer excludes propylene/ethylene multi-block copolymers. The term "polyolefin," as used herein, refers to a polymer which comprises a majority molar amount of a polymerized olefin, such ethylene or propylene.

The term "amine-reactive group," as used herein, refers to a chemical group or chemical moiety that can react with an amine group.

The term "hydroxyl-reactive group," as used herein, refers to a chemical group or chemical moiety that can react with a hydroxy group.

The term "crosslinked foam," as used herein, refers to a partially crosslinked foam (gel content less than 50 weight percent) or a fully crosslinked foam (gel content of 50 weight percent or more). Gel content is measured in accordance with ASTM D- 2765-01, Procedure A. The gel content in an inventive foam is typically greater than 60 weight percent, based on the total weight of the foam.

The term "functionalized foam," as used herein, refers to a polyolefin foam containing at least one bonded chemical structure derived from Compound I, as defined herein.

The terms "thermal treatment" and "thermally treated," and like terms, as used herein, refer to a process of increasing the temperature of a material or composition. Suitable means for increasing temperature include, but are not limited to, applying heat using an electrical heating source, or applying heat using a form of radiation.

MEASUREMENTS

By the term "MI," is meant melt index, I₂, in g/10 min, measured using ASTM D-1238-04-04, Condition 190°C/2.16 kg for ethylene-based polymers (Condition 230°C/2.16 kg for propylene-based polymers, and designated as MFR (melt flow rate)). Differential Scanning Calorimetry (DSC) can be used to measure crystallinity in ethylene-based (PE) samples and propylene-based (PP) samples. A sample is pressed into a thin film at a temperature of 190⁰C. About five to eight milligrams of film sample is weighed and placed in a DSC pan. The lid is crimped on the pan to ensure a closed atmosphere. The sample pan is placed in a DSC cell, and then heated, at a rate of approximately 10°C/min, to a temperature of 180⁰C for PE (230⁰C for PP). The sample is kept at this temperature for three minutes. Then the sample is cooled at a rate of 10°C/min to -60⁰C for PE (-40⁰C for PP), and kept isothermally at that temperature for three minutes. The sample is next heated at a rate of 10°C/min until complete melting (second heat). The percent crystallinity is calculated by dividing the heat of fusion (H_f), determined from the second heat curve, by a theoretical heat of fusion of 292 J/g for PE (165 J/g, for PP), and multiplying this quantity by 100 (for example, % cryst. = (H_f / 292 J/g) x 100 (for PE)).

Unless otherwise stated, melting point(s) (T_m) of each polymer sample is determined from the second heat curve obtained from DSC, as described above. The crystallization temperature (T_c) is measured from the first cooling curve.

Reported polymer densities were measured according to ASTM D-792-00. Density for foam specimen was measured according to ASTM D-297-93. After the foams are prepared, they are left to cool at room temperature for at least 24 hours before any testing is conducted. A piece of foam of approximate dimensions "lcm x lcm" was cut, and weighted on an analytical balance. The foam specimen was then dipped into alcohol and blotted dry, a procedure which aided in removing air bubbles in the subsequent submersion into water. Finally the specimen was submersed into a beaker of water, and held under water with a metallic weight, and weighed. The weight of the beaker of water and metallic weight was measured. Density was calculated according to the following equation: Density at 25degC in Mg/m³ = 0.9971 x A/(A - (B - C)), where

A = mass of specimen in grams

B = mass of specimen in beaker of water and metallic weight

C = mass of beaker of water and metallic weight

Hardness (Shore A and Asker C) was measured according to ASTM D-2240-

05. Each sample was conditioned for a minimum of 12 hours before testing, preferably, 7 days or more after production. Conditioning occurred at 23 +/- 2 degrees Celsius and humidity of 50 +/- 1%. Asker C measurement device was a Teclock GS-701N. Shore A measurement device was a PTC Instruments, ASTM Type A Durometer - Model 306L.

For each measurement, the test specimens had a minimum thickness of 6 mm, and the surface area was 5 cm x 5 cm. The tests were performed at the conditioning conditions, and at a minimum of 12 mm from any edge of the specimen.

When the specimen was skinned, the measurements were taken with the skin on top of the plate and centered. The hardness scale was measured about 10 seconds after applying the pressure. The average of five measurements was reported, with the five measurements taken at different positions on the specimen, with at least 6 mm distance between each measurement site.

A core measurement (core hardness (Shore A)) was performed by measuring the middle section of the foam. The middle section is accessed by slicing the foam into two sections approximately half-way (approximately 7.5 mm from the centre) along the thickness axis.

Gel level (percent gels) was measured according to ASTM D-2765-01, Procedure A. The solvent was xylene. Each sample was ground to particle sizes that could pass through a U.S. No. 30 sieve, yet not pass through a U.S. No. 60 sieve. One gram of each sample was mixed in 1750 ml of xylene. Then, 51 grams of an antioxidant was added to the mixture. The antioxidant used was Cyanox 2246 (2,2'- methylenebis(4-methyl-6-tert-butylphenol), commercially available from Cytec Industries Inc. The mixture was boiled for 12 hours. The gels were extracted, and placed in a vacuum oven, at less than 28 inches mercury, and 150 degrees Celsius, for 12 hours. The gels were cooled for one hour in a dessicator. The gels were then weighed. The analysis was performed in duplicate.

NMR studies: A model system was employed, where hexadecane was used to simulate a hydrocarbon polymer and TEMPO was used instead of 4-hydroxy- TEMPO due to improved solubility in hexadecane. Using this substitution, quantitative measurements can be determined from the relative peak intensities of the different species in the solution NMR spectrum. The reactivity of TEMPO and 4-hydroxy- TEMPO are believed to be the same towards carbon centre free radicals. The experimental procedure for the NMR studies to estimate the TEMPO grafting efficiency in the presence of dicumylperoxide are detailed as follow. One skilled in the art can develop an appropriate NMR study for other systems using the information provided below and knowledge known in the art.

NMR solution experiments were performed on a Varian INOVA 400 MHz spectrometer. The 13C-NMR analysis of the model system was performed using a capillary containing D₂O to provide a lock signal, so as to avoid any issue with radical reaction with the solvent, and was performed at room temperature.

The model system contains 15 wt% dicumylperoxide and 3 wt% TEMPO in hexadecane solution, with hexadecane making up the remaining 82 wt%. This solution was heated for 25 minutes at 14O⁰C to decompose the peroxide for initiating the grafting reaction, and the NMR measurements were then taken at room temperature, where decomposition does not take place over the time of the measurement acquisition, effectively freezing the extent of the reaction for observation. The extent of reaction in terms of TEMPO at this point was found from the NMR spectrum to be approximately 70%, based on the NMR peak intensities of unreacted TEMPO, methylated TEMPO and grafted TEMPO. Of the reacted TEMPO, the mole ratio of "TEMPO adducted to hexadecane" to "TEMPO adducted to methyls" is 1.3:1, determined from relative NMR peak intensities of the respective species, and giving an approximate grafting efficiency of 57%. Should the reaction go to completion, there is no reason to believe that this grafting efficiency should be different, and it can be concluded, that based on the starting amount of TEMPO, 57% of the molecules is expected to graft onto the hydrocarbon polymer, and the other 43% react with methyl radicals.

Also, at this point in the reaction, the mole ratio of phenyl isopropanol to acetophenone was observed to be 1.1:1, as determined from the relative NMR peak intensities, so the dicumylperoxide decomposes to approximately equal number of moles of oxy and methyl radicals. The oxy radical abstracts hydrogen from the hexadecane, and TEMPO reacts with the subsequently formed hydrocarbon radical to effect grafting. As for the methyl radical, it can either react with the hexadecadecane, which forms hydrocarbon radical to react with TEMPO to effect grafting, or with TEMPO to form methylated TEMPO. The NMR data above, indicating the fate of TEMPO reaction with hexadecane or methyl radical, showed that there was only a slight increase in mole ratio of grafted TEMPO and methylated TEMPO to 1.3:1, over the phenyl isopropanol to acetophenone ratio of 1.1 : 1. Should all the methyl radicals react with hexadecane, there would be no methylated TEMPO. The current distribution of grafted versus methylated TEMPO indicates that 9% of the number of methyl radicals reacted with hexadecane, while the majority (91%) reacted with TEMPO. As hexadecane is in excess to both peroxide and TEMPO, the generated methyl radical has a much higher statistical probability to react with the hexadecane. Since most of the methyl radicals reacted with TEMPO, this indicated that this reaction was fast and likely to be diffusion controlled. This also indicated that TEMPO reacted preferentially with carbon centre free radicals.

The levels of peroxide and 4-hydroxy-TEMPO used in the present invention are different than those of the model system, and the use of hexadecane is a simplification of a polymer melt environment. Nonetheless, the grafting efficiency determined for the model system is believed to apply to the hydroxy- TEMPO as well. Although at a lower level of peroxide, the amount of peroxide does not determine the fate of the 4-hydroxy- TEMPO, as it reacts with carbon centre radicals, and not peroxoyl radicals. Regardless of the level of peroxide, as soon as it decomposes, the same mechanism applies, where the oxy radical abstracts hydrogen on the polymer to create a hydrocarbon free radical, or the oxy radical further decomposes to acetophenone and methyl radical. In this part of the mechanism, the amount of peroxoyl radicals attacking a hydrocarbon polymer is expected to be similar to the hexadecane model. Similarly, the alternative pathway, where the methyl radical reacts with the polymer or 4-hydroxy- TEMPO applies also. In this case in a polymer melt, diffusion is slower than in a hexadecane solution, so the probability of a methyl radical encountering 4-hydroxy- TEMPO is lower than in solution, and such radical will likely encounter the polymer in the melt to create hydrocarbon free radicals on the polymer than in the model system, leading to more grafting of 4-hydroxy-TEMPO onto the polymer. Hence, the grafting efficiency of 4-hydroxy-TEMPO in a polymer system should be at least similar to, if not greater than, that in the model system.

EXPERIMENTAL

The following examples illustrate, but do not, either explicitly or by implication, limit the present invention.

Materials

The materials used in this study are the following.

Engage™ 7256 is a random ethylene-butene copolymer from The Dow Chemical Company of the following characteristics: 2.0 melt index at 190⁰C, 2.16 kg load, and a density of 0.885 g/cc (cc = cm³).

Engage™ 7086 is a random ethylene-butene copolymer from The Dow Chemical Company of the following characteristics: < 0.5 melt index at 190⁰C, 2.16 kg load, and a density of 0.901 g/cc.

Elvax™ 265 is an ethylene-vinylacetate copolymer from Dupont de Nemoir of the following characteristics: a 28% vinylacetate copolymer with a 3.0 melt index at 190⁰C, 2.16 kg load, and a density of 0.955 g/cc. The compound 4-hydroxy-2,2,6,6-tetramethyl-l-piperidinyloxy (or 4-hydroxy TEMPO), is available from A H Marks and Company Ltd.

Calcium carbonate, zinc oxide, zinc stearate, stearic acid, azobisformamide and dicumylperoxide were provided by E-Foam Materials Technology Company of Taiwan.

Adhesive: a MMA-grafted polychloroprene contact adhesive from Kwok Po Chemical Company in Hong Kong of grade number of 295A, was used to evaluate the adhesion of the foam substrates. This adhesive was reported to have approximately 20% solids content in methylethylketone solvent, and is an adhesive used in the footwear industry.

Isocyanate: Desmodur RFE, a polymeric isocyanate of 27% solids content in ethylacetate solvent, with 7.2% active NCO, was from Bayer.

Dicumylperoxide: a 100% active peroxide was supplied by Sou Le Enterprise Co., Ltd. in Taiwan Azobisformamide: this material was supplied by Taishin Chemical Industries

Co., Ltd. in Taiwan by the tradename of AAlOO.

Compositions used in Foams

The compositions for use in foams are described in Table 1 below.

Table 1: Compound composition used in the preparation of the foam substrates

Note [I]: 4-hydroxy-TEMPO was added first to Engage 7086 to create a masterbatch with 0.3% level of TEMPO, and subsequently 67 parts of the masterbatch was used in the final preparation of formulation 2i Note [2]: 4-hydroxy-TEMPO was added first to Elvax 265 to create a masterbatch with 2.5% level of TEMPO, and subsequently 4 and 8 parts of the masterbatch were added to 3i and 4i, respectively, during the final formulation preparations

Preparation of Foams

The compounds used to create the foams were prepared on a 2-roll mill. The compounds were subsequently heated in a close mold, after which, the curing was completed, and the mold opened to release the rapidly expanding foam. The associated conditions are listed in Table 2 below.

Table 2: Preparation conditions of the compounds and foam substrates, and foam substrates' characteristics

* Mold cavity = 10 cm x 10 cm x lcm. Closed mold and air tight. When open mold, sample foam expands.

The foam substrates formed by compression foaming create a plastic skin layer, which is smooth, and has a relatively low surface area for adhesion compared to foam surfaces with the skin removed. Adhesion evaluations were carried out with the skin intact. Substrate surfaces are cleaned with running tap water, and wiped dry with lint-free towels.

Adhesive Testing

Two foam substrates (each 10 cm length, 7 mm thickness, original width 2 cm, and each cut out from expanded foam), each formed from the same inventive or comparative composition, as discussed above, were adhesively bonded together using an adhesive composition based on the 295A MMA-grafted polychloroprene, as described below.

The adhesive 295 A was further formulated with approximately 10%, by weight, of Desmodur RFE, to form the final adhesive composition. Such adhesive compositions typically have pot lives of a few hours; however, to minimize variations in the viscosity, the adhesive was used within 30 minutes of preparation. A layer of adhesive, approximately 0.3 mm thick, was applied to both the foam skin surfaces to be bonded, and the specimens were dried either at 25⁰C or 8O⁰C. Bonding of the foam substrates to each other was done by mating the surfaces together, and applying a force of approximately 6 kg/cm for 45 seconds. Afterwards, the specimens were left indoor at ambient conditions for five days, before they were tested for adhesion peel strength. The 180 degree peel strength, commonly referred to as the T-peel strength test, for each specimen was carried out on an INSTRON 5544 unit, at a pull speed of 25 mm/minute. Peel force was reported in Newtons, and the width of the foam sample was measured after the peel test, to ensure the exact width dimension. The final peel adhesion was calculated in accordance with Equation (1) below, and reported as kg/cm, a unit commonly used in the adhesive industry for reporting peel adhesion Peel adhesion (kg/cm) = {Peel force (N) x 9.8 (kg/N)} / Width (cm) (Eqn. 1)

Results are shown in Tables 3 and 4 below. Table 3 shows the T-peel strengths of foam-to-foam adhesion bonded by solvent-based polychloroprene adhesive as a function of hydroxyl-TEMPO content. Table 4 shows the T-peel strengths of foam-to-foam adhesion for Sample 4i bonded by solvent-based polychloroprene adhesive as a function of isocyanate hardener in the polychloroprene adhesive.

Table 3: T-peel strengths of foam-to-foam adhesion

Reactive hydroxyl content per carbon center on the polymer, based on a 50% grafting efficiency, as determined by 13 C/ NMR Table 4: T-peel strengths of foam-to-foam adhesion for Sample 4i

Note [I]: Based on total weight of approximately 30 grams of adhesive plus hardener

Note [2] : One ply of adhesive was applied, and dried at 80⁰C for 3 minutes, and bonded immediately

Note [3]: The first ply of adhesive was applied, and dried at 80⁰C for 10 minutes, and cooled at 25⁰C for 10 minutes, and subsequently a second ply of adhesive was applied and dried at room temperature for 10 minutes, after which the substrate was bonded immediately

Conclusion The data in Table 3 demonstrate that when 4-hydroxy-TEMPO is present during the peroxide curing process, the adhesion peel strength increased by more than five-fold over the reference sample Ic, and in the case of sample 4i, the peel strength increased by a factor of 10. The data in Table 4 further demonstrates that the presence of isocyanate hardener in the polychloroprene adhesive will improve the adhesion between the foams.

Claims

CLAIMS:

1. A process for producing a functionalized, crosslinked foam, said process comprising thermally treating a composition comprising the following: a) at least one polyolefin; b) at least one blowing agent, c) at least one initiator, and d) at least one grafting agent represented by Compound I, as shown below:

(I),

wherein R¹ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched,

R⁴ is either hydrogen, or a C1-C20 hydrocarbyl radical, which is linear or branched, Z is either OH, SH, NH₂ or NHR⁵, and wherein R⁵ is a C1-C20 hydrocarbyl radical, which is linear or branched; and and wherein the compound is grafted onto the polyolefin, while the polyolefin is crosslinked and foamed, to form a functionalized, crosslinked foam.

2. The process of Claim 1, wherein the compound is grafted onto the polyolefin, with an efficiency greater than 25 percent, based on the weight of Compound I, while the polyolefin is crosslinked and foamed, to form a functionalized, crosslinked foam.

3. The process of Claim 1 or Claim 2, wherein the at least one initiator comprises an organic peroxide.

4. The process of Claim 3, wherein the organic peroxide is present in an amount greater than the amount of Compound I.

5. The process of Claim 1 or Claim 2, wherein the initiator is an organic peroxide, and wherein the crosslinked foam has a gel content, as measured according to ASTM D-2765-01, Procedure A, of at least 50 weight percent, based on the total weight of the foam.

6. The process of any of the preceding claims, wherein the polyolefin is present in an amount greater than, or equal to, 80 weight percent, based on the total weight of the composition.

7. The process of any of the preceding claims, wherein the blowing agent is a chemical blowing agent.

8. The process of any of the preceding claims, wherein the polyolefin is an ethylene/α-olefin interpolymer.

9. The process of Claim 8, wherein the ethylene/α-olefin interpolymer is a homogeneously branched linear interpolymer or a homogeneously branched substantially linear interpolymer.

10. The process of Claim 8 or Claim 9, wherein the ethylene/α-olefin interpolymer has a density from 0.857 g/cc to 0.910 g/cc.

11. The process of any of Claims 8-10, wherein the ethylene/α-olefin interpolymer has a melt index from 0.5 g/10 min to 30 g/10 min.

12. The process of any of the preceding claims, wherein the composition is thermally treated for a period of time to crosslink the foam to a gel content of at least 50 weight percent, based on the total weight of the foam.

13. The process of any of the preceding claims, wherein the composition is thermally treated for greater than, or equal to, 8 minutes, and wherein the initiator is dicumylperoxide.

14. The process of Claim 13, wherein the initiator is dicumylperoxide.

15. The process of any the preceding claims, wherein the composition is thermally treated at a temperature greater than, or equal to, 160⁰C.

16. The process of Claim 14, wherein the initiator is dicumylperoxide.

17. The process of any of the preceding claims, wherein the crosslinked foam comprises at least 0.00008 mole "Z group" per mole of CH₂ group.

18. The process of any of the preceding claims, wherein the initiator is a peroxide, which is present in an amount from 0.6 phr to 1.5 phr, based on hundred parts of the polyolefin.

19. The process of any of the preceding claims, wherein the blowing agent is present in an amount less than, or equal to 10.0 phr, based on hundred parts of the polyolefin.

20. The process of any of the preceding claims, wherein the Compound I is present in an amount greater than, or equal to, 0.05 phr, based on hundred parts of the polyolefin.

21. The process of any of the preceding claims, wherein the Compound I is present in an amount less than, or equal to, 0.5 phr, based on hundred parts of the polyolefin.

22. The process of any of the preceding claims, wherein Compound I is present in an amount from 0.05 phr to 0.25 phr, based on hundred parts of the polyolefin.

23. The process of any of the preceding claims, wherein the initiator is a peroxide, and the molar ratio of peroxoyl radical to Compound I is less than, or equal to, 40.

24. The process of any of the preceding claims, wherein the initiator is a peroxide, and the molar ratio of peroxoyl radical to Compound I is greater than, or equal to, 2.5.

25. The process of any of the preceding claims, wherein the initiator is a peroxide, and the molar ratio of peroxoyl radical to Compound I is from 2.5 to 40.

26. The process of any of the preceding claims, wherein the initiator is a peroxide, and the molar ratio of peroxoyl radical to Compound I is from 6 to 30.

27. The process of any of the preceding claims, wherein Compound I is present in an amount less than, or equal to 0.25 phr, based on hundred parts of polyolefin, and wherein the molar ratio of peroxoyl radical to Compound I is from 2.5 to 40.

28. The process of any of the preceding claims, wherein Compound I is present in an amount less than, or equal to 0.20 phr, based on hundred parts of polyolefin, and wherein the molar ratio of peroxoyl radical to Compound I is from 2.5 to 40.

29. The process of any of the preceding claims, wherein the composition does not contain an azo blowing agent.

30. The process of any of the preceding claims, wherein the Z group is hydroxyl group.

31. A foam formed by the process of any of Claims 1-30.

32. The foam of Claim 31, wherein the Z group on Compound I is present in the crosslinked foam in an amount greater than, or equal to, one Z group per 24,000 carbon centers.

33. The foam of Claim 31 or Claim 32, wherein the foam has a reduction of at least 10 percent in the "surface hardness (Shore A) to core hardness (Shore A) differential," compared to this differential in a foam, similar in all aspects, except formed without the Compound I.

34. A foam formed from a composition comprising: a) at least one polyolefin; b) at least one blowing agent, c) at least one initiator, and d) at least one grafting agent represented by Compound I, as shown below:

35. The foam of Claim 34, wherein the Z group on Compound I is present in the crosslinked foam in an amount greater than, or equal to, one Z group per 24,000 carbon centers.

36. The foam of Claim 34 or Claim 35, wherein the foam has a reduction of at least 10 percent in the "surface hardness (Shore A) to core hardness (Shore A) differential," compared to this differential in a foam, similar in all aspects, except formed without the Compound I.

37. An article comprising at least one component formed from the foam of any of Claims 31-36.

38. The article of Claim 37, wherein the at least one component is a foam substrate.

39. The article of Claim 37, wherein the article is a shoe sole.

40. The article of Claim 37, wherein the article is a building material.

41. The article of Claim 37, wherein the article is an insulation material.

2. The article of Claim 37, wherein the article is an automotive part.