WO2025133985A1 - Adhesive article release layers comprising diphenyl urethane compound - Google Patents

Abstract

Adhesive articles are described comprising a substrate; a release layer comprising a release compound disposed on the substrate; wherein the release compound has the formula (Formula 1) wherein X is -CH₂-; L is a divalent linking group comprising a urethane moiety; and R1 and R2 independently comprise a C4-C30 hydrocarbon group; and an adhesive bonded to the release layer. The release layer typically further comprises an organic polymer. Also described are compositions comprising an organic polymer and the compound of Formula 1, and methods of making compositions and release layers.

Description

ADHESIVE ARTICLE RELEASE LAYERS COMPRISING

DIPHENYL URETHANE COMPOUND

Summary

In one embodiment, an adhesive article is described comprising a substrate; a release layer comprising an organic polymer and a release compound disposed on the substrate; wherein the release compound has the formula:

(Formula 1) wherein

X is -CH2-;

L is a divalent linking group comprising a urethane moiety; and

R1 and R2 independently comprise a C4-C30 hydrocarbon group; and an adhesive bonded to the release layer.

In some embodiments, the release layer comprises a first major surface proximate the substrate and a second major surface proximate the adhesive wherein the second surface comprises a higher concentration of the release compound than the first major surface.

In some embodiments, the organic polymer and release compound are soluble at a concentration of 10 wt.% in an organic solvent selected from tetrahydrofuran, 2-methyltetrahydrofuran, toluene, cyclopentanone, 2-butanone, xylenes, 2-propanol, n-propanol, methanol, and mixtures thereof.

In some embodiments, the organic polymer is thermoplastic.

In some embodiments, the (e.g. thermoplastic) organic polymer is crosslinked.

In another embodiment, a release liner article is described comprising a substrate; and a release layer comprising the release compound of Formula 1 disposed on the substrate. The release layer typically further comprises an organic polymer.

In other embodiments, compositions are described comprising an organic polymer and the compound of Formula 1.

In other embodiments, methods of making compositions and release layers are described.

Fig. 1 is a side view of an article including a backing, a release coating on a major surface, and a pressure sensitive adhesive on the opposing major surface of the backing;

Fig. 2 is a side view of another article comprising a release coated backing and a separate pressure sensitive adhesive coated substrate;

Fig. 3 is a side view of another article comprising a backing with release coating on both major surfaces and a pressure sensitive adhesive between the release-coated surfaces.

Figs. 4 is an infrared spectroscopy plot of C18MDIC18.

Figs. 5 is an infrared spectroscopy plot of ODI-BPF-ODI.

Detailed

Release

The compound, suitable for use as a release agent, is typically prepared by reaction of diphenyl diisocyanate (e.g. MDI) with a hydroxyl functional compound (i.e. a monofunctional alcohol) having a hydrocarbon chain of sufficient chain length. In typical embodiments, the isocyanate is 4,4 ’-methylene diphenyl diisocyanate, depicted as follows:

In other embodiments, the MDI may comprise other isomers including 2,2 ’-methylene diphenyl diisocyanate, 3,3 ’-methylene diphenyl diisocyanate, and 2,4 ’-methylene diphenyl diisocyanate. MDI is commercially available from various suppliers include Sigma Aldrich and Dow Inc.

The hydrocarbon chain of the hydroxyl functional compound is typically saturated, or in other words comprises an alkyl group. In other embodiments, the hydrocarbon chain may be unsaturated, or in other words comprises an alkene or alkenyl group.

The hydroxyl functional compound has the formula:

CH₃(CH₂)nOH wherein n ranges from 4 to 30 carbon atoms.

In some embodiments, the hydrocarbon group CH₃(CH₂)n- comprises at least 6, 7, 8, 9, or 10 carbon atoms. In some embodiments, the hydrocarbon group CH₃(CH2)n- comprises at least 11, 12, 13, 14, 15, 16, 17, 18 carbon atoms. In some embodiments, the hydrocarbon group CH₃(CH₂)n- comprises no greater than 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, or 18 carbon atoms. The hydrocarbon group may optionally be fluorinated.

Examples of the linear alcohols include for example octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetanol, cetostearyl alcohol, stearyl alcohol, and behenyl alcohol. An example of a linear unsaturated higher alcohol include oleyl alcohol. Examples of the branched higher alcohols include for example 2-hexyldecanol , 2-octyl dodecanol , and 2-decyl tetradodecanol. An example of an alcohol having a (e.g. aliphatic) hydrocarbon group in combination with a divalent aromatic hydrocarbon group (e.g. arylene) is 4-n-butylphenol. Thus, the hydrocarbon group can be aliphatic, aromatic, or comprise a combination of aliphatic and aromatic hydrocarbon groups.

In some embodiments, the purity of the hydrocarbon chain reactants (e.g. alcohol or isocyanate) is at least 90, 95, or 97%. When a single reactant (e.g. alcohol, octadecanol) is utilized and the purity of the reactant is at least 90, 95, or 97%, the percentage of hydrocarbon (e.g. alkyl) groups of the resulting release compound having a specific chain length (e.g. 18) is the same are the purity of the reactant. In these embodiments, less than 10, 5, or 3 wt.% of the hydrocarbon (e.g. alkyl) groups have a different chain length (due to the purity of the reactant).

In some embodiments, at least 90% of the total R1 and R2 hydrocarbon groups have a chain length of 8-30, 8-22, 8-18, 10-18, or 12-18. In some embodiments, at least 95, 96, or 97% of the total R1 and R2 hydrocarbon groups have a chain length of 8-30, 8-22, 8-18, 10-18, or 12-18.

In some embodiments, at least 90% of the total R1 and R2 groups have a hydrocarbon chain length of at least 10. In some embodiments, at least 95, 96, or 97% of the total R1 and R2 have a hydrocarbon chain length of at least 10.

In some embodiments, at least 90% of the total R1 and R2 groups have a hydrocarbon chain length of at least 12. In some embodiments, at least 95, 96, or 97% of the total R1 and R2 have a hydrocarbon chain length of at least 12.

In some embodiments, at least 90% of the total R1 and R2 groups have a hydrocarbon chain length of at least 18. In some embodiments, at least 95, 96, or 97% of the total R1 and R2 have a hydrocarbon chain length of at least 18.

In other embodiments, a combination of alcohols with different hydrocarbon chain lengths may be utilized in the preparation of the diphenylmethane release compound.

The ratio of the number of moles of the alcohol to the number of moles of the diphenylmethane di-isocyanate is typically 2 : 1 or slightly more than 2 : 1 such that all the isocyanate groups have been reacted.

The release compound has the formula:

(Formula 1) wherein

X is -CH₂-;

L is a divalent linking group comprising a urethane moiety; and R1 and R2 independently comprise a C4-C30 hydrocarbon group.

In typical embodiment, the urethane moiety, represented by “L” is -NHC(O)O- or -OC(O)NH-. However, L may comprise other organic linking groups in addition to the urethane moiety, provided that the organic linking group does not diminish the described release or contact angle properties. In some embodiments, R1 and R2 are both hydrocarbon groups such as alkyl or alkenyl. In other embodiments, R1 and/or R2 comprise a terminal aliphatic hydrocarbon group in combination with an aromatic group, such as in the case of utilizing 4-n-buty Iphenol. Thus, R1 and/or R2 can comprise an aromatic moiety in combination with a terminal hydrocarbon group. It is also contemplated that the hydrocarbon group may comprise substituents (e.g. fluoroalkyl).

The release compound typically has a molecular weight of at least about 400 g/mole (398.5 g/mole when R1 and R2 are each butyl). In some embodiments, the molecular weight of the release compound is at least 400, 600, 700 g/mole (e.g. 791.3 when R1 and R2 are each C18). ). In some embodiments, the molecular weight of the release compound is no greater than 1500, 1400, 1300, 1200, 1100, 1000, or 800 g/mole.

The release compound typically has a melt temperature Tm (onset of an endotherm or maximum), as determined by Differential Scanning Calorimetry of at least 95, 100, 105, 110, 115, 120, 125, 130°C. The melt temperature of the release compound typically is typically no greater than 175, 170, 165, 160, 155, 150, 145, or 135°C. In some embodiments, the release compound has a melt temperature Tm no greater than 125, 120, 115, 110, 105, or 100°C.

When the release compound is prepared by reaction of diphenylmethane diisocyanate with a hydroxyl functional compound, as described above, the resulting compound has the formula:

(Formula 1A)

Alternatively the release compound, may be prepared by reaction of diphenylmethane diol with an isocyanate functional compound having a longer chain hydrocarbon (e.g. octadecyl isocyanate). In this embodiment, the resulting compound has the formula:

(Formula IB)

When the release compound is derived from diphenylmethane diisocyanate or diphenylmethane diol, X is methylene (-CH2-).

The release layer typically comprises the release compound described herein combined with an organic polymer. The release layer may comprise a single (e.g. methylene) diphenyl urethane compound or a mixture of compounds. The amount of release compound is typically at least 0.01, 0.02, 0.03, 0.05, 0.075, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 wt.%, based on the total amount of release compound(s) and organic polymer. Sufficiently low average release forces can typically be obtained with release compound concentration of no greater than 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.1, or 0.05 wt.% based on the total amount of release compound(s) and organic polymer.

However, the release layer and mixture of (e.g. thermoplastic) organic polymer and release compound may comprise greater amounts of release compound(s). The amount of release compound may be at least 20, 30, 40, 50, 60, 70, 80, 90 wt.% or greater based on the total amount of release compound(s) and organic polymer. In some embodiments, the amount of release compound may be no greater than 90, 80, 70, 60, 50, 40, 30, 20. or 10 wt.% based on the total amount of release compound(s) and organic polymer. Premixing the release compound with a (e.g. thermoplastic) organic polymer can be especially useful for providing very low concentration of the release compound. For example a more concentrated mixture of the release compound premixed with a (e.g. thermoplastic) organic polymer may be fed to a thermal extruder.

When the release layer is applied to a substrate, it is typically a homogeneous mixture of release compound and organic polymer. In some embodiments, such as when greater average release values are obtained (e.g. greater than 200 g/inch), the release layer of the adhesive article may also comprise homogeneous mixture of release compound and organic polymer. In other embodiments, wherein lower average release values are obtained (e.g. less than 200, 100, or 50 g/inch) the release layer typically comprises a first major surface proximate the substrate and a second major surface proximate the adhesive. The second surface comprises a higher concentration of the release compound than the first major surface. The drying conditions can also promote the migration and self-assembly of the release compound at the second major surface. A release compound wherein X is -CH2-, L is -NHC(O)O- and R1 and R2 are C18, comprises 3.8% nitrogen based on the atomic percentage. As demonstrated by the X- ray photoelectron Spectroscopy (XPS) Analysis, the amount of nitrogen at the release layer surface (that contacts the adhesive) can be at least 3-3.3 atomic % for such release compound. Depending on the selection of X, L, Rl, and R2 the atomic % of nitrogen can vary depending on the compound. However, the ratio of the atomic% of nitrogen at the release layer surface compared to the atomic% of nitrogen of the compound can express the concentration ratio. For example, when the release compound and the release layer surface both have 3.8 atomic % of nitrogen, 100% of the release compound is concentrated at the surface (3.8/3.8 = 1 X 100%). As yet another example, when the compound has 3 atomic % nitrogen and the release layer surface has 1.5 atomic % nitrogen, 50% of the release compound is concentrated at the surface (1.5/3 = 0.5 X 100%). In some embodiments, at least 50, 60, 70, 80, 90% or greater of the release compound is concentrated at the release layer surface that contacts the adhesive. The release layer surface may be characterized by contact angle properties. In some embodiments, the (e.g. second major surface of the) release layer has a static contact angle with diiodomethane of at least 45 or 50 degrees ranging up to 75, 80, or 85 degrees. In some embodiments, the (e.g. second major surface of the) release layer has a static contact angle with n-hexadecane of at least 30 or 35 degrees ranging up to 45, 50, or 55 degrees. In some embodiments, the (e.g. second major surface of the) release layer has a static contact angle with dimethylsiloxane of at least 20 degrees ranging up to 30, 35, 40, 45, 50, 55, 60, 65, 70, or 75 degrees. The contact angles are indicative of low surface energy and repellency.

In typical embodiments, the release compound described herein is free of both silicon (e.g. siloxane, silyl) and/or fluorine. Thus, the release layer can also be free of both silicon and/or fluorine.

With reference to Figs. 5 and 6, the urethane groups of the (e.g. release) compound contain a readily available N-H bond which is highly capable of hydrogen bonding. Such urethane groups can be proton donors and proton acceptors. The release compound forms a molecular assembled structure driven by this strong intermolecular hy drogen bonding. High absorbance of the urethane groups, as determined by infrared spectroscopy, is indicative of hydrogen bonding. Peak absorbances of the urethane groups in the same wavelength range after one or two melting and cooling cycles is indicative of thermal stability of the (e.g. release) compound.

It is surmised that organic polymers that lack or have low hydrogen bonding can be preferred for concentrating the release compound on the surface. Less hydrogen bonding between the organic polymer and (e.g. release) compound promotes the molecular assembly of the (e.g. release) compound. However, organic polymers with greater amounts of hydrogen bonding can be preferred for uniformly distributing the release compound within the organic polymer. However, more hydrogen bonding between the organic polymer and (e.g. release) compound can interrupt the molecular assembly of the (e.g. release) compound. The (e.g. release) compound can more readily form hydrogen bonds with (methjacrylate monomers than a (methjacrylic polymer since (methjacrylic polymers are less mobile than (methjacrylate monomers. Further, multifunctional (methjacrylate monomers having at least two or three (methjacrylate monomers have multiple hydrogen donor and acceptor sites. Thus, the release layer is typically not a (methjacrylic polymer prepared by combining the (e.g. release) compound with (e.g. multifunctional) (methjacrylate monomer and curing the (methjacrylate monomers. However, when low concentrations of multifunctional (methjacrylate monomers are used as chemical crosslinking agent, the disruption of the molecular assembly is minimal, especially when the multifunctional acrylate is combined with a polymer . Lower re-adhesion values can be indicative of diminished molecular assembly which can result in some transfer of the (e.g. release) compound or uncured (e.g. (meth)acrylate) monomer to the adhesive surface.

Organic Polymer

The release layer typically comprises one or more diphenyl urethane compounds, as described herein, combined with an organic polymer. The organic polymer can improve the adhesion of the (e.g. methylene) diphenyl urethane release compounds described herein to the substrate. The organic polymer can also improve the durability of the release layer surface.

The preferred organic polymer can vary depending on the substrate and the desired average release properties. Suitable polymers include for example polyesters, acrylic polymers or in other words poly(meth)acrylates including polymethylmethacrylate and acrylic block copolymers, polyurethanes, styrenic block copolymers, polyvinyl chloride (PVC), polycarbonate, polyetherimide, polyamide, polysulfone, polystyrene, polylactic acid (PLA), and polyolefins.

In some embodiments, the organic (e.g. aci lic) polymer does not comprise a high concentration of polymerized units of low glass transition temperature (Tg) monomers. Notably, release values of greater than 1000 g/inch were obtained when the organic polymer was polybutylmethacrylate and a silicone adhesive (3M8403 tape utilized in the examples).

In some embodiments, the organic polymer is amorphous. Amorphous polymers are typically more soluble in organic solvents for solvent based release coatings are compared to crystalline polymers. However, crystalline polymers are often preferred for thermally extruded release layers. Further, mixtures of amorphous and crystalline polymers can be utilized.

The molecular weight of the organic polymer is typically at least 10,000, 50,000, 100,000; 200,000, 300,000, or 500,000 g/mole (as measured by Gel Permeation Chromatography using polystyrene standards). The molecular weight of the organic polymer is typically no greater than at least 2,000,000 or 1,500,000 or 1,000,000 g/mole. In some embodiments, the organic polymer has a molecular weight no greater than 500,000 or 250,000 g/mole.

Mooney viscosity is indicative of molecular weight. In some embodiments, the Mooney viscosity of the organic (e.g. polyolefin) polymer is at least 40, 50, 60, or 70 ML( 1+4) at 125°C. In some embodiments, the Mooney viscosity of the organic (e.g. polyolefin) polymer is no greater than 100, 90, or 80 ML(l+4) at 125°C. Mooney viscosity is indicative of molecular weight. In some embodiments, the Mooney viscosity is at least 10, 20, or 30 ML(l+4) at 100°C. In some embodiments, the Mooney viscosity is no greater than 50 or 40 ML(l+4) at 100°C.

In some embodiments, the organic polymer is a thermoplastic polymer (i.e. polymers that soften and become more fluid at elevated temperature and solidify upon cooling). In some embodiments, the thermoplastic organic polymer has a thermal transition, i.e. a melt temperature or glass transition temperature as determined by Differential Scanning Calorimetry in a range from 100°C to 450°C. In some embodiments, the organic polymer has a thermal transition at a temperature less than 400, 350, 300, or 250°C. Although thermoplastic polymers typically can be reversibly melted and solidified, it is also contemplated to crosslink the thermoplastic polymer after applying the release layer to the substrate. The (e.g. thermoplastic) polymer can be crosslinked with a chemical crosslinking agent or crosslinked by exposure to actinic (e.g. e-beam) radiation.

The melt flow index is indicative of an organic polymer being thermoplastic and thermally processable by thermal extrusion. The melt flow index (as measured using ASTM D 1238-23 A or ISOOl 133) is also indicative of molecular weight. In some embodiments, the organic (e.g. polyolefin) polymer has a melt flow index of at least 2.5, 5 or 10 g/10 min at a temperature in the range of 120°C-200°C. In some embodiments, the melt flow rate temperature is 120, 130, 140, 150, 160, 170, 180, or 190°C. In some embodiments, the organic (e.g. polyolefin) polymer has a melt flow index of no greater than 50, 25, 15, or 10 g/10 min. at a temperature in the range of 120°C-200°C.

In other embodiments, the organic polymer may be melt processable at higher temperatures. In this embodiment, the organic polymer has a melt flow index of at least 2.5, 5 or 10 g/10 min at a temperature in the range of 200°C - 400°C. In some embodiments, the organic polymer has a melt flow index of at least 2.5, 5 or 10 g/10 min. at a temperature of 250, 300, 350, or 400°C.

In some embodiments, the organic polymer of the release layer comprises a polyolefin.

As used herein polyolefins refers to polymers comprising at least 50 wt.% of polyolefin moieties. In some embodiments, the polyolefin polymer comprises at least 60, 70, 80, 90 wt.% or greater of polyolefin moieties.

The polyolefin moiety is typically derived from ethylene, propylene, and butylene (including isobutylene), and combination thereof. In some embodiments, the polyolefin comprises (e.g. ethylenically) unsaturated polyolefin moieties, such as butadiene. In some embodiments, the polyolefin comprises saturated or unsaturated polyolefin moieties comprises greater than 4 carbon atoms such as butadiene, hexene and octene, particularly in the case of polyolefins prepared with metallocene catalysts. In some embodiments, the amount of unsaturated moieties (e.g. diene) is at least 1, 2, 3, 4, or 5 wt.% or mol% based on the total polymer. In some embodiments, the amount of unsaturated moieties (e.g. diene) is no greater than 15 or 10 wt.% or mol%. The polyolefin polymers may be linear, branched, grafted orblock copolymers.

Polyolefins include for example high, medium, low and linear low density polyethylene, ethylene/acrylic acid copolymer, ethylene/vinyl acetate copolymer, ethylene/propylene copolymer including terpolymers, polypropylene, ethylene/propylene/diene copolymer (EPDM), and polymethylpentene.

In some embodiments, the organic polymer is a styrenic block copolymers comprising styrene end blocks and conjugated diene midblock including for example styrene-isoprene-styrene (SIS), styrene-ethylene/butylene-styrene block copolymers (SEBS), styrene-butadiene-styrene (SBS), styrene-isobutylene-styrene (SIBS), and acrylonitrile-butadiene-styrene block copolymer. When the organic polymer is a block copolymer comprising at least 50 wt.% polyolefin moieties, it may be characterized as a polyolefin. Styrenic block copolymers can comprise styrene end blocks in an amount of at least 10, 15, 20, 25, 30, 35, 40, 45, or 50 wt.% based on the total weight of the block copolymer. The amount of conjugated diene midblock is typically at least 50, 55, 60, 65, 70, 75, 80, 85, or 90 wt.% based on the total weight of the block copolymer. There is typically one unsaturation per diene (e.g. butadiene or isoprene). When partially hydrogenated the amount of unsaturation can be lower.

Various blends of polyolefin polymers can be utilized. Further, one or more polyolefin polymers can be blended with other polymers that comprise less than 50 wt.% polyolefin moieties or no polyolefin moieties. In some embodiments, an organic (e.g. polyolefin) polymer that provide higher average release values (e.g. polystyrene) may be combined with a second organic polymer that provides lower average release values (e.g. styrenic block copolymer) to adjust the release values to a particular range. The weight ratio of polyolefin (e.g. styrenic block copolymer) to second polymer (e.g. polystyrene) may be at least 1:1, 1.5: 1, 2:1, 2.5:1, 3: 1, 3.5: or 4:1. In this embodiment, the organic polymer blend/mixture comprises a polyolefin polymer (i.e. styrenic block copolymer), yet the mixture of polymers comprises less than 50 wt.% polyolefin.

In some embodiments, the organic polymer is a polyurethane. Polyurethanes are prepared from reacting one or more polyols with one or more polyisocyanates. In some embodiments, the polyol has a number average molecular weight of at least 400, 450, or 500 Daltons (Da). In some embodiments, the polyol has a number average molecular weight of no greater than 10,000 Da, 5,000 Da, or 2,000 Da. In some embodiments, the polyol may be at least one of a polyester polyol, a polyether polyol, a polycarbonate polyol and a hydroxyl terminated polybutadiene. Combinations of different types of polyols may be used.

Suitable polyester polyols include, but are not limited to, polybutylene adipate, polyethylene adipate, poly(diethylene glycol adipate), polyhexamethylene adipate, poly(neopentyl glycol) adipate, poly(butylene adipate-co-phthalate), polycaprolactone or copolymers thereof. Combinations of different polyester polyols may be used.

Common diisocyanates include for example dicyclohexylmethane-4,4’ -diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-phenylene diisocyanate, 1,3 -phenylene diisocyanate, m- xylylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, poly(hexamethylene diisocyanate), 1,4-cyclohexylene diisocyanate, 4-chloro-6-methyl- 1,3 -phenylene diisocyanate, 4,4’- diphenylmethane diisocyanate, 2,4 ’-diphenylmethane diisocyanate, 1,4-diisocyanatobutane, 1,8- diisocyanatooctane, 2,5-toluene diisocyanate, methylene bis(o-chlorophenyl diisocyanate, (4,4’- diisocyanato-3,3’,5,5’-tetraethyl) diphenylmethane, 4, 4 ’-diisocyanato-3, 3 ’-dimethoxybiphenyl (o- dianisidine diisocyanate), 5-chloro-2,4-toluene diisocyanate, l-chloromethyl-2,4-diisocyanato benzene, tetramethyl-m-xylylene diisocyanate, 1,12-diisocyanatododecane, 2-methyl-l,5-diisocyanatopentane, 2,2,4-trimethylhexyl diisocyanate, or a mixture thereof.

Although (e.g. small concentrations of) polyol having at least three hydroxyl groups and/or polyisocyanates having at least three isocyanate group can be utilized, predominantly diol(s) and diisocyanates are utilized in case of thermoplastic polyurethanes. Various thermoplastic polyurethane are commercially available from Huntsman. When the polyurethane is prepared from greater concentrations of polyol having at least three hydroxyl groups and/or polyisocyanates having at least three isocyanate group, the polyurethane may be characterized as a crosslinked polyurethane. Crosslinked organic polymers including polyurethanes are typically insoluble in organic solvent(s) as described herein.

In other embodiments, the organic polymer is a thermoset that can permanently harden into a solid state during (e.g., thermal) curing. In other embodiments, the organic polymer is a thermoset resin that has been (e.g., thermally) cured. Common thermoset materials include melamine, polyester resin, urea-formaldehyde, vinyl ester resin, epoxy resin, polyimide, phenolic resins, polymers prepared from cyclic dienes (e.g., polynorbomene). Such organic polymers typically have a glass transition temperature (Tg) of at least 50°C prior to curing. Both thermoset organic polymers and cured thermoset resins typically have a Tg significantly greater than 50°C after curing. Prior to curing, the Tg of an organic polymer can be determined by Dynamic Mechanical Analysis or Differential Scanning Calorimetry. After curing, such materials are highly crosslinked such that the resulting organic polymers typically do not exhibit a thermal transition (Tg or Tm) prior to the decomposition temperature of the organic polymer.

The organic polymer can comprise a wide variety of functional groups that can participate in crosslinking of the oiganic polymer. The functional group can be within the backbone of the polymer of pendent. Other illustrative functional groups include for example alkynyl, halogen, thiol/mercapto, alkoxy silyl-, amine, nitrile, and acid/acid anhydride. Illustrative polymers with alkynyl functional groups includes homo and (e.g. block) copolymers of 4-(phenylethynyl)styrene such as described L.B. Sessions, et al. Macromolecules, 2005, 38, 2116-2121. Illustrative polymer with halogen functional groups include halogenated (e.g. brominated) rubber such as brominated copolymers of butadiene and styrene available from Lanxess as trade designation LANXESS EMARALD INNOVATION 3000. Illustrative polymers with thiol/mercapto functional groups includes thiol-terminated polyether liquid polymer such as commercially available from Toray as trade designation POLYTHIOL QE-340M. Illustrative polymers with alkoxy silyl functional groups includes silane-terminated polyethers such as available from Wacker as trade designation WACKER GENIOSIL STP-E10. Illustrative polymers with amine functional groups includes copolymers of poly(4-aminostyrene) and poly(l-lysine hydrobromide) commercially available from Poly sciences as catalog number 02823. Illustrative polymers with nitrile functional groups includes polyarylene ether nitriles, acrylonitrile butadiene rubber, and polycyanoarylene ether polymers described in US4812507. Acrylic polymers often comprise (e.g. carboxylic or phosphonic) acidic functional group. Further various polyolefins are commercially available with acid anhydride (e.g. maleic anhydride) functional groups. Mixtures of polymers with functional groups can be utilized. Further, an organic polymer with functional group may be combined with an organic polymer lacking functional groups. In some embodiments, the type and amount of functional groups is selected to promote molecular assembly of the (e.g. release) compound.

The release layer may comprise a single organic polymer or mixture thereof. In some embodiments, the amount or organic polymer(s) (of the dried coating) is typically at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 wt.% of the release layer. Organic Solvent Solutions

In some embodiments, the organic polymer is dissolved in an organic solvent forming an organic polymer solution. The organic polymer solution typically comprises at least 5, 6, 7, 8, 9, or 10 wt.% solids organic polymer. The wt.% solids of the organic polymer of the organic polymer solution is typically no greater than 15 wt.%.

The release compound is typically combined with the organic polymer solution. The release compound is dispersible and preferably soluble in the organic solvent. In some embodiments, the organic solvent is selected from tetrahydrofuran, 2-methyltetrahydrofuran, toluene, cyclopentanone, 2-butanone, and mixtures thereof. In some embodiments, the organic solvent further comprises up to 30% of other solvents, such as isopropanol, n-propanol, ethanol, methanol, and ethyl acetate. Various solvent mixtures are described in the forthcoming examples. It is appreciated that the preferred solvent or solvent mixture may be different for different organic polymers. In some embodiments, the release compound may be dissolved in a first solvent or solvent mixture and the organic polymer dissolved in a second solvent or solvent mixture. The first solvent or solvent mixture with the release compound is then combined with the second solvent or solvent mixture with the organic polymer.

It is appreciated that organic polymers that are dissolvable in an organic solvent are not crosslinked. However, it is contemplated to crosslink the organic polymer after applying to the substrate, as previously described. In other embodiments, the (e.g. polyurethane) organic polymer may be prepared from polymerizing the component thereof (e.g. polyisocyanate and polyol) after applying the components to the substrate. Crosslinked organic polymer is typically insoluble in organic solvent (e.g. the same organic solvent(s) as the coating composition) at a concentration of 5 or 10 wt.% solids (release composition) at 25°C. In some embodiments, the crosslinked organic polymer is insoluble in organic solvent at a concentration ranging from 50 to 100 wt.%. When the organic polymer is highly crosslinked at least 60, 70, 80, 90 wt.% or greater is typically insoluble in organic solvent. When the organic polymer is less crosslinked at least 10, 20, 30, or 40 wt.% may be insoluble in organic solvent.

Additives

In some embodiments, the (e.g. release) composition optionally further comprises one or more additives. Additives include for example one or more antioxidants, light (e.g. UV) stabilizers, leveling agents, thermal stabilizers, rheology modifier, colorants, UV or fluorescent dyes, antimicrobial compositions, fillers, plasticizers, and the like. The one or more additives typically can be present in the composition in amounts ranging from about 0.01 wt.% to 10 wt.% based on the total composition and may depend on the type of additive and the final properties of the release coating. In some embodiments, the total amount of additives is no greater than 9, 8, 7, 6, 5, 4, 3, 2, or 1 wt.% of the total solids (i.e. excluding any solvent that may be present) composition.

The (e.g. release) composition optionally further comprises one or more chemical crosslinking agents. Chemical crosslinking agents typically comprise at least 2 or 3 functional groups that covalent bond with a functional group of the organic polymer. Illustrative functional groups include for example thiol/mercapto, amine, epoxy, hydroxyl, (e.g. alkyl)halide, and ethylenically unsaturated functional groups such as multifunctional (meth)acrylates. Multifunctional thiol/mercapto compounds (e.g. PETMP, CATMP, and DMPPG) can crosslink polymers having functional groups such as alkyne and nitrile. Multifunctional amines (e.g. triethylamine) can crosslink polymers having functional groups such as halogen or nitrile. Multifunctional epoxy compounds (e.g. glycerol polyglycidyl ether) can crosslink polymers having functional groups such as thiol/mercapto. amine, and acidic groups. Multifunctional hydroxyl compounds (e.g. glycerol, ethylene glycol) can crosslink polymers having functional groups such as amines. Multifunctional alkoxyl silyl compounds can crosslink polymers having hydroxyl groups. Multifunctional alkyl halide compounds can crosslink polymers having functional groups such as amine. Organic acids (e.g. p-toluene sulfonic acid) can be utilized to crosslink polymers having nitrile groups.

Multifunctional (meth)acrylate compounds can react with other free radicals as well as thiol and amine. Examples of multifunctional (meth)acrylate compounds include, but are not limited to, glycerol di(meth)acrylate, hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3 -propanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,4-cyclohexanediol di(meth)acrylate, urethane di(meth)acrylate, and polyethylene glycol di(meth)acrylates. Examples of crosslinking monomers with three (meth)acryloyl groups include, but are not limited to, glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,2,4-butanetriol tri(meth)acrylate, and pentaerythritol tri(meth)acrylate. Examples of crosslinking monomers with four or more (meth)acryloyl groups include, but are not limited to, pentaerythritol tetra(meth)acrylate, sorbitol hexa(meth)acrylate.

Various other chemical crosslinking agents and reactions are known. In some embodiments, catalysts are included to accelerate the crosslinking, as known in the art.

In some embodiments, the (e.g., release) composition comprises a free radical initiator. The free- radical initiator can be a thermal initiator or a photoinitiator.

Suitable thermal free radical initiators include various azo compounds such as those commercially available under the trade designation VAZO from Chemours Co. (Wilmington, DE, USA) including VAZO 67, which is 2,2 ’-azobis(2 -methylbutane nitrile), VAZO 64, which is 2,2’- azobis(isobutyronitrile), VAZO 52, which is (2,2’-azobis(2,4-dimethylpentanenitrile), and VAZO 88, which is l,l’-azobis(cyclohexanecarbonitrile); various (e.g. organo)peroxides such as benzoyl peroxide, cyclohexane peroxide, lauroyl peroxide, di-tert-amyl peroxide, tert-butyl peroxy benzoate, di-cumyl peroxide, and peroxides commercially available from Atofina Chemical, Inc. (Philadelphia, PA, USA) under the trade designation LUPERSOL (e.g., LUPERSOL 101, which is 2,5-bis(tert-butylperoxy)-2,5- dimethylhexane, and LUPERSOL 130, which is 2,5-dimethyl-2,5-di-(tert-butylperoxy)-3-hexyne); various hydroperoxides such as tert-amyl hydroperoxide, tert-butyl hydroperoxide, and cumene hydroperoxide; and mixtures thereof.

Illustrative photoinitiators include benzoin ethers (e.g., benzoin methyl ether or benzoin isopropyl ether) or substituted benzoin ethers (e.g., anisoin methyl ether). Other exemplary photoinitiators are substituted acetophenones such as 2,2-diethoxyacetophenone or 2, 2-dimethoxy -2 -phenylacetophenone (commercially available under the trade designation IRGACURE 651 from BASF Corp. (Florham Park, NJ, USA) or under the trade designation ESACURE KB-1 from Sartomer (Exton, PA, USA)). Still other exemplary photoinitiators are substituted alpha-ketols such as 2-methyl-2 -hydroxypropiophenone, aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride, and photoactive oximes such as 1- phenyl-l,2-propanedione-2-(O-ethoxycarbonyl)oxime. Other suitable photoinitiators include, for example, 1 -hydroxy cyclohexyl phenyl ketone (commercially available under the trade designation IRGACURE 184), bis(2,4,6-trimethylbenzoyl)phenyl phosphine oxide (commercially available under the trade designation IRGACURE 819), l-[4-(2 -hydroxyethoxy )pheny 1] -2 -hydroxy -2-methyl-l -propane- 1- one (commercially available under the trade designation IRGACURE 2959), 2-benzyl-2-dimethylamino-

1-(4-morpholinophenyl)butanone (commercially available under the trade designation IRGACURE 369),

2-methyl-l-[4-(methylthio)phenyl]-2-morpholinopropan-l-one (commercially available under the trade designation IRGACURE 907), and 2-hydroxy-2-methyl-l-phenyl propan-l-one (commercially available under the trade designation DAROCUR 1173 from Ciba Specialty Chemicals Corp. (Tarrytown, NY, USA)).

Other free radical photoinitiators are acyl phosphine oxides such as those described, for example, in U.S. Patent 4,737,593 (Ellrich et al.).

The amount of chemical crosslinking agent (such as crosslinking monomer and/or free radical initiator(s)) is typically in a range of 0.01 to 5 weight percent based on the total weight of organic polymer components of the composition. The amount can be at least 0.01, 0.05, 0.1, 0.2, 0.5, or 1 wt.% based on the total solids of the organic polymer and release compound(s). The amount of chemical crosslinking agent is typically no greater than 5, 4, 3, 2, 1, or 0.5 wt.%.

Method of Making

A method of making a composition is described comprising combining an organic polymer and at least one (e.g. methylene) diphenyl urethane compound. When the composition further comprises an organic solvent, both the organic polymer and release compounds are preferably soluble and/or dispersible in the organic solvent. Most preferably a homogenous solution is formed. To achieve a controlled and uniform release coating, a preferred coating method is capable of controlling the coating solution temperature to the point of application to the substrate. For example, when die coating in roll-to- roll processing the solution supply vessel, supply lines and coating die can be temperature controlled.

In other embodiments, precursor components to an organic polymer may be combined with least one (e.g. methylene) diphenyl urethane compound and an organic solvent. For example, in case of a polyurethane the precursor components are polyol and polyisocyanate, as previously described. In this embodiment, the precursor components polymerize forming the organic polymer in the presence of the (e.g. methylene) diphenyl urethane compound(s). Although it is preferred to combine the release compound with an organic polymer to promote migration and self-assembly of the release compound at a major surface of the release layer that will come in contact with the adhesive, it is also contemplated to coat an organic solvent solution comprising the (e.g. methylene) diphenyl urethane release compound(s) alone (i.e. without organic polymer) to the surface of a (e.g. organic polymer) substate. In this embodiment, the surface layer may comprise 100% (e.g. methylene) diphenyl urethane release compound(s). However, if the solvent dissolves a portion of the organic polymer of the substrate, the surface layer may further comprise low concentrations of organic polymer (e.g. less than 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 wt.% organic polymer).

When the organic polymer is melt-processable, the organic polymer and release compound may be thermally combined. Further, the release layer may be applied to the substrate via thermal extrusion. In this embodiment, the composition comprising the organic polymer and release compound as well as the method is free of organic solvent(s). Melt-processable compositions and melt processable substrates are also more amenable to recycling.

When making a release liner, the method typically further comprises applying the composition to a substrate. The release compositions described herein may be applied to a substrate (e.g. tape backing) by means of conventional coating techniques such as wire-wound rod, (e.g. direct, kiss, reverse) gravure, 3 roll sand 5 roll coating, air-knife, spray coating, notch-bar coating, knife coating, slot die coating (including application to a tensioned web), immersion dip coating, curtain coating and trailing blade coating.

The thermal extrusion coating equipment may be heated such that the release composition remains above its melting point. The organic solvent coating solutions are typically heated to a temperature in the range of 40°C - 80°C to maintain an uniform solution, or to avoid precipitation of organic polymer and release compound. This may include any combination of heated vessels for delivery such as heated tubing, heated pumping elements, heated coating dies/fluid applicators, and heated rolls (e.g. for conveying the substrate). The temperature may be controlled to the same temperature or different temperatures throughout the coating process. The temperature may be controlled by any acceptable means, i.e. resistive heating tape, recirculating fluid (e.g. water, oil), infrared, etc. In some embodiments, the release composition remains above the melting temperature of the (e.g. methylene) diphenyl urethane compound as it is dispensed onto the substrate.

Depending on the coating method, the coating may be a continuous or discontinuous coating. The thickness or mass per area of the release coating can vary. In some embodiments, the coating has a thickness of at least 0.0025 microns (25 nanometers) ranging up to 25 microns. In some embodiments, the discontinuous coating has a mass per area of at least 0.0025 grams per square meter (gsm) ranging up to 25 gsm. In some embodiments, the thickness/mass per area is at least 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5 microns or gsm. In some embodiments, the thickness/mass per area is no greater than 10, 9, 8, 7, 6, or 5 microns or gsm. When the release layer is formed by applying a solution comprising organic solvent and the release compound, the organic solvent is removed by drying. The drying temperature and time can vary depending on the drying equipment utilized. In some embodiments, the organic solvent-containing coating is dried at room temperature or a temperature below the melt temperature of the release compound. In this embodiment, the dried coating may also be heat treated at a temperature of at least 120, 130, 140 or 150°C. In some embodiments, the organic solvent-containing coating is dried at temperature of at least 80, 90, 100, 110, 120, 130, 140 or 150°C for a sufficient duration of time. In some embodiments, the drying and/or heat treatment temperature is at or above the melt temperature of the release compound. Such process conditions is favorable to concentrating the release compound on the release layer surface and promoting molecular assembly of the (e.g. release) compound, i.e. the opposite surface as the substrate.

The release layer prepared from thermal extrusion may also be heat treated at the temperatures described above.

In some embodiments, the method of making the release layer or film comprising stretching and annealing. The (e.g. coextruded) substrate and release layer may be stretched at least 100, 150, 200, 250, 300, or 350%. The stretching may comprise uniaxial or biaxially stretching. The stretching can reduce the thickness of the layers. When the organic polymer is sufficiently crystalline, the strethching results in orientation or in other words an increase in birefringence. The annealing temperature may range from 170-230°C.

When the organic polymer (or precursor components thereof) is crosslinked, the method may comprise exposing the applied organic polymer and (e.g. release) compound to heat, actinic radiation, or a combination thereof to crosslink the organic polymer. In typical embodiments, the heat treatment temperatures described above are suitable for crosslinking the organic polymer in the presence of a thermal free radical initiator.

One useful class of actinic light sources are light emitting diodes (“LED”). LED ultraviolet (UV) sources are advantageous because they provide UV light over a much narrower wavelength range compared with other UV light sources such as black lights and mercury lamps. LED sources are commercially available that emit radiation, for example, at 395 nm or 405 nm.

Other actinic light sources includes UV black light and mercury lamps. A UV black light is a relatively low light intensity source that provides generally 10 mW/cm² or less (as measured in accordance with procedures approved by the United States National Institute of Standards and Technology as, for example, with a UVIMAP UM 365 L-S radiometer manufactured by Electronic Instrumentation & Technology, Inc., Sterling, VA) over a wavelength range of 280 nm to 400 nm. A mercury lamp is a higher intensity broad-spectrum UV source capable of providing intensities generally greater than 10 mW/cm², and preferably between 15 and 6000 mW/cm². For example, an intensity of 600 mW/cm² and an exposure time of about 1 second may be used successfully. Intensities can range from 0.1 mW/cm² to 6000 mW/cm² and preferably from 0.5 mW/cm² to 3000 mW/cm². The release coating can be applied to a wide variety of substrates (e.g. tape backings).

Useful flexible substrates include, but are not limited to, paper, poly-coated Kraft paper, supercalendered or glassine Kraft paper, organic polymer films such as polyolefins including poly(propylene), biaxially -oriented polypropylene, poly(ethylene), poly(vinyl chloride) ethylene vinyl acetate; polycarbonate, poly (tetrafluoroethylene), polyester [e.g., polyethylene terephthalate)], polyethylene naphthalate), polyimide film such as DuPont's KAPTON™, polystyrene, cellulose acetate, ethyl cellulose, and polylactic acid (PLA).

Suitable substrates may also be formed of metal, metal foil, metallized (co)polymeric film, or ceramic sheet material. Substrates may also take the form of a cloth backing, e.g. a woven fabric formed of threads of synthetic fibers, or a nonwoven web or substrate, or combinations of these.

In some embodiments, the thickness of the substrate is at least 0.5, 1 or 2 mils and typically no greater than 5, 10 or 15 mils.

One or both major surfaces of the substrate (e.g. backing) may further comprise a primer layer or be surface treated (e.g. corona treated), as known in the art to promote adhesion of the release coating, adhesive or both.

One illustrative PSA article 100 is shown in FIG. 1. This embodied (e.g. tape) article comprise release coating 110 disposed on a major surface of substrate (e.g. backing) 120 and a pressure sensitive adhesive 130 disposed on the opposing major surface of 120.

FIG. 2 depicts another PSA article 200. This embodied article comprising a release coating 210 disposed on a major surface of substrate (e.g. backing) 220. A pressure sensitive adhesive 230 is releasably bonded to the release coating 210. The pressure sensitive adhesive is disposed on a major surface of a second substrate 221. FIG. 3 depicts another PSA article 300. This embodied (e.g. tape) article comprises release coatings 310 and 311 disposed on both major surfaces of substrate (e.g. backing) 320 and a pressure sensitive adhesive 330 releasably bonded to release coating 311. One or both of release coatings 310 and 311 are a release coating as described herein. When release coatings are disposed on both major surfaces, the release coating may comprise the same or different release coatings, such as release coating with different amounts of release compound(s).

When the organic polymer and (e.g. release) compound are thermally extruded at a sufficient thickness, a free-standing release liner film is formed in the absence of a substrate. An organic polymer substrate layer may be coextruded with one or more release layers.

The adhesive article can be a tape, strip, sheet (e.g., perforated sheet), label, roll, web, disc, and kit (e.g., an object for mounting and the adhesive tape used to mount the object).

Adhesive

The release coating described herein is suitable for use with a variety of adhesive compositions.

Suitable (e.g. pressure sensitive) adhesives include natural or synthetic rubber-based pressure sensitive adhesives, acrylic pressure sensitive adhesives, vinyl alkyl ether pressure sensitive adhesives, silicone pressure sensitive adhesives, polyester pressure sensitive adhesives, polyamide pressure sensitive adhesives, poly-alpha-olefins, polyurethane pressure sensitive adhesives, and styrenic block copolymer based pressure sensitive adhesives.

The adhesives may be organic solvent-based, a water-based emulsion, hot melt (e.g. such as described in US 6,294,249), heat activatable, as well as an actinic radiation (e.g. e-beam, ultraviolet) curable adhesives. In some embodiments, the organic solvent is removed from the pressure sensitive adhesive prior to contacting the adhesive with the release coating described herein. In other embodiments, the hot melt adhesive is contacted with the release coating at a temperature below the melt temperature of the release coating composition. In some embodiments, dry lamination of the adhesive can provide lower release values than adhesives that are solvent coated.

In typical embodiments, the adhesive is a pressure sensitive adhesive generally have a storage modulus (E’) as can be measured by Dynamic Mechanical Analysis at room temperature (25°C) of less than 3 x 10⁶ dynes/cm at a frequency of 1 Hz.

The pressure sensitive adhesive may further include one or more suitable additives such as crosslinking agents (e.g. multifunctional (meth)acrylate crosslinkers (e.g. TMPTA), epoxy crosslinking agents, isocyanate crosslinking agents, melamine crosslinking agents, aziridine crosslinking agents, etc.), tackifiers (e.g., phenol modified terpenes and rosin esters such as glycerol esters of rosin and pentaerythritol esters of rosin, as well as C5 and C9 hydrocarbon tackifiers), thickeners, plasticizers, fillers, antioxidants, ultraviolet absorbers, antistatic agents, surfactants, leveling agents, colorants, flame retardants, and silane coupling agents.

It is appreciated that different release compositions are preferred for different pressure sensitive adhesive compositions. It is also appreciated that different types of adhesive articles have different preferred release properties.

The release layer can be evaluated with a variety of different adhesive compositions of commercially available tapes, including the tapes described in the forthcoming examples. The release layer can also be evaluated with Testing Tape 1, having a 25 micron thick layer of hot melt adhesive comprising a mixture of 100 parts of SIS block copolymer (having a styrene content of 14.3%, a coupling efficiency of 88% and a melt index of 9 g/10 min (condition G)), 85 parts of tackifying resin (C9 modified C5 having a softening point of 87°C) and 2 parts of antioxidant disposed on a 50 micron thick of corona treated BOPP film.

In some embodiments, the adhesive is a silicone adhesive. Silicone adhesives advantageously can form aggressive bonds with many materials including silicone release liners. Thus, developing release liners for silicone adhesive is particularly challenging.

Silicone adhesive generally comprise a silicone material according to the following formula illustrating a siloxane backbone with aliphatic and/or aromatic substituents:

(Formula 2) wherein Rl, R2, R3, and R4 are independently selected from the group consisting of an alkyl group and an aryl group, each R5 is an alkyl group and n and m are integers, and at least one of m or n is not zero. In some embodiments, one or more of the alkyl or aryl groups may contain a halogen substituent, e.g., fluorine. For example, in some embodiments, one or more of the alkyl groups may be -CH2CH2C4F9.

In some embodiments, R5 is a methyl group, i.e., the nonfunctionalized poly diorgano siloxane material is terminated by trimethylsiloxy groups. In some embodiments, R1 and R2 are alkyl groups and n is zero, i.e., the material is a poly(dialkylsiloxane). In some embodiments, the alkyl group is a methyl group, i.e., poly(dimethylsiloxane) (“PDMS”). In some embodiments, R1 is an alkyl group, R2 is an aryl group, and n is zero, i.e., the material is a poly(alkylarylsiloxane). In some embodiments, R1 is methyl group and R2 is a phenyl group, i.e., the material is poly(methylphenylsiloxane). In some embodiments, R1 and R2 are alkyl groups and R3 and R4 are aryl groups, i.e., the material is a poly (dialkyldiarylsiloxane). In some embodiments, R1 and R2 are methyl groups, and R3 and R4 are phenyl groups, i.e., the material is poly(dimethyldiphenylsiloxane).

In some embodiments, the nonfunctionalized polydiorganosiloxane materials may be branched. For example, one or more of the Rl, R2, R3, and/or R4 groups may be a linear or branched siloxane with alkyl or aryl (including halogenated alkyl or aryl) substituents and terminal R5 groups.

As used herein, “nonfunctional groups” are either alkyl or aryl groups consisting of carbon, hydrogen, and in some embodiments, halogen (e.g., fluorine) atoms. As used herein, a “nonfunctionalized polydiorganosiloxane material” is one in which the Rl, R2, R3, R4, and R5 groups are nonfunctional groups.

Generally, functional silicone systems include specific reactive groups attached to the poly siloxane backbone of the starting material (for example, hydrogen, hydroxyl, vinyl, allyl, or acrylic groups). As used herein, a “functionalized polydiorganosiloxane material” is one in which at least one of the R-groups of Formula 2 is a functional group.

In some embodiments, a functional polydiorganosiloxane material comprises at least two R-groups that are functional groups. Generally, the R-groups of Formula 2 may be independently selected. In some embodiments, at least one functional group such as hydride group, a hydroxy group, an alkoxy group, a vinyl group, an epoxy group, and an acrylate group. When the polydiorganosiloxane is non-functional polydiorganosiloxane, the polydiorganosiloxane lacks such functional groups.

In addition to functional R-groups, some of the R-groups may be nonfunctional groups, e.g., alkyl or aryl groups, including halogenated (e.g., fluorinated) alky and aryl groups. In some embodiments, the functionalized poly diorganosiloxane materials may be branched. For example, one or more of the R groups may be a linear or branched siloxane with functional and/or non-functional substituents.

Other silicone materials comprise siloxane moieties in addition to other moieties in the backbone, such as urea, amide, oxamide, and urethane.

Suitable siloxane polyurea block copolymers may have the following Formula 3 :

wherein each R is a moiety that, independently, is an alkyl moiety, having about 1 to 12 carbon atoms, and may be substituted with, for example, trifluoroalkyl or vinyl groups, a vinyl radical or a higher alkenyl radical, a cycloalkyl moiety having from about 6 to 12 carbon atoms and may be substituted with alkyl, fluoroalkyl, and vinyl groups, or an aryl moiety having from about 6 to 20 carbon atoms and may be substituted with, for example, alkyl, cycloalkyl, fluoroalkyl and vinyl groups or R is a perfluoroalkyl group as described in US Patent No. 5,028,679, or a fluorine-containing group, as described in US Patent No. 5,236,997, or a perfluoroether-containing group, as described in US Patent Nos. 4,900,474 and 5,118,775; typically, at least 50% of the R moieties are methyl radicals with the balance being monovalent alkyl or substituted alkyl radicals having from 1 to 12 carbon atoms, alkenyl radicals, phenyl radicals, or substituted phenyl radicals; each Z is a polyvalent radical that is an arylene radical or an aralkylene radical having from about 6 to 20 carbon atoms, an alkylene or cycloalkylene radical having from about 6 to 20 carbon atoms, in some embodiments Z is 2,6-tolylene, 4,4’-methylenediphenylene, 3,3 ’-dimetho xy-4,4’- biphenylene, tetramethyl-m-xylylene, 4,4 ’-methylenedicyclo hexylene, 3,5,5-trimethyl-3- methylenecyclohexylcne, 1,6-hexamethylene, 1,4-cyclo hexylene, 2,2,4-trimethylhexylene and mixtures thereof; each Y is a polyvalent radical that independently is an alkylene radical of 1 to 10 carbon atoms, an aralkylene radical or an arylene radical having 6 to 20 carbon atoms; each D is selected from the group consisting of hydrogen, an alkyl radical of 1 to 10 carbon atoms, phenyl, and a radical that completes a ring structure including B or Y to form a heterocycle; where B is a polyvalent radical selected from the group consisting of alkylene, aralkylene, cycloalkylene, phenylene, heteroalkylene, including for example, polyethylene oxide, polypropylene oxide, polytetramethylene oxide, and copolymers and mixtures thereof; m is a number that is 0 to about 1000; n is a number that is at least 1; and p is a number that is at least 10, in some embodiments 15 to about 2000, or even 30 to 1500. Useful siloxane polyurea block copolymers are disclosed in, e.g., US Patent Nos. 5,512,650, 5,214,119, 5,461,134, and 7,153,924 and PCT Publication Nos. WO 96/35458, WO 98/17726, WO 96/34028, WO 96/34030 and WO 97/40103.

Another useful class of elastomeric siloxane polymers that can be prepared from amine- functional polysiloxanes are oxamide-based polymers such as polydiorganosiloxane polyoxamide block copolymers. Examples of polydiorganosiloxane polyoxamide block copolymers are presented, for example, in US Patent Publication No. 2007/0148475. The polydiorganosiloxane polyoxamide block copolymer contains at least two repeat units of the following Formula 4:

In this formula, each R¹ is independently an alkyl, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo, wherein at least 50 percent of the R¹ groups are methyl. Each Y is independently an alkylene, aralkylene, or a combination thereof. Subscript n is independently an integer of 40 to 1500 and the subscript p is an integer of 1 to 10. Group G is a divalent group that is the residue unit that is equal to a diamine of formula R³HN-G-NHR³ minus the two -NHR³ groups. Group R³ is hydrogen or alkyl (e.g., an alkyl having 1 to 10, 1 to 6, or 1 to 4 carbon atoms) or R³ taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group (e.g., R³HN-G- NHR³ is piperazine or the like). Each asterisk (*) indicates a site of attachment of the repeat unit to another group in the copolymer such as, for example, another repeat unit of Formula 4.

Suitable alkyl groups for R¹ in Formula 3 typically have 1 to 10, 1 to 6, or 1 to 4 carbon atoms. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, isopropyl, n-propyl, n-butyl, and iso-butyl. Suitable haloalkyl groups for R¹ often have only a portion of the hydrogen atoms of the corresponding alkyl group replaced with a halogen. Exemplary haloalkyl groups include chloroalkyl and fluoroalkyl groups with 1 to 3 halo atoms and 3 to 10 carbon atoms. Suitable alkenyl groups for R¹ often have 2 to 10 carbon atoms, optionally substituted with halo (e.g. fluoro). Exemplary alkenyl groups often have 2 to 8, 2 to 6, or 2 to 4 carbon atoms such as ethenyl, n-propenyl, and n-butenyl. Suitable aryl groups for R¹ often have 6 to 12 carbon atoms. Phenyl is an exemplary aryl group. The aryl group can be unsubstituted or substituted with an alkyl (e.g., an alkyl having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms), an alkoxy (e.g., an alkoxy having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms), or halo (e.g., chloro, bromo, or fluoro). Suitable aralkyl groups for R¹ usually have an alkylene group having 1 to 10 carbon atoms and an aryl group having 6 to 12 carbon atoms. In some exemplary aralkyl groups, the aryl group is phenyl and the alkylene group has 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms (i.e., the structure of the aralkyl is alkylene-phenyl where an alkylene is bonded to a phenyl group).

At least 50 percent of the R¹ groups are methyl. For example, at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, at least 95 percent, at least 98 percent, or at least 99 percent of the R¹ groups can be methyl. The remaining R¹ groups can be selected from an alkyl having at least two carbon atoms, haloalkyl, aralkyl, alkenyl, aryl, or aryl substituted with an alkyl, alkoxy, or halo.

Each Y in Formula 3 is independently an alkylene, aralkylene, or a combination thereof. Suitable alkylene groups typically have up to 10 carbon atoms, up to 8 carbon atoms, up to 6 carbon atoms, or up to 4 carbon atoms. Exemplary alkylene groups include methylene, ethylene, propylene, butylene, and the like. Suitable aralkylene groups usually have an arylene group having 6 to 12 carbon atoms bonded to an alkylene group having 1 to 10 carbon atoms. In some exemplary aralkylene groups, the arylene portion is phenylene. That is, the divalent aralkylene group is phenylene-alkylene where the phenylene is bonded to an alkylene having 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. As used herein with reference to group Y, “a combination thereof’ refers to a combination of two or more groups selected from an alkylene and aralkylene group. A combination can be, for example, a single aralkylene bonded to a single alkylene (e.g., alkylene-arylene-alkylene). In one exemplary alkylene-arylene-alkylene combination, the arylene is phenylene and each alkylene has 1 to 10, 1 to 6, or 1 to 4 carbon atoms.

Each subscript n in Formula 3 is independently an integer of 40 to 1500. For example, subscript n can be an integer up to 1000, up to 500, up to 400, up to 300, up to 200, up to 100, up to 80, or up to 60. The value of n is often at least 40, at least 45, at least 50, or at least 55. For example, subscript n can be in the range of 40 to 1000, 40 to 500, 50 to 500, 50 to 400, 50 to 300, 50 to 200, 50 to 100, 50 to 80, or 50 to 60.

The subscript p is an integer of 1 to 10. For example, the value of p is often an integer up to 9, up to 8, up to 7, up to 6, up to 5, up to 4, up to 3, or up to 2. The value of p can be in the range of 1 to 8, 1 to 6, or 1 to 4.

Group G in Formula 3 is a residual unit that is equal to a diamine compound of formula R³HN-G- NHR³ minus the two amino groups (i.e., -NHR³ groups). Group R³ is hydrogen or alkyl (e.g., an alkyl having 1 to 10, 1 to 6, or 1 to 4 carbon atoms) or R³ taken together with G and with the nitrogen to which they are both attached forms a heterocyclic group (e.g., R³HN-G-NHR³ is piperazine). The diamine can have primary or secondary amino groups. In most embodiments, R³ is hydrogen or an alkyl. In many embodiments, both of the amino groups of the diamine are primary amino groups (i.e., both R³ groups are hydrogen) and the diamine is of formula H2N-G-NH2.

In some embodiments, G is an alkylene, heteroalkylene, polydiorganosiloxane, arylene, aralkylene, or a combination thereof. Suitable alkylenes often have 2 to 10, 2 to 6, or 2 to 4 carbon atoms. Exemplary alkylene groups include ethylene, propylene, butylene, and the like. Suitable heteroalkylenes are often polyoxyalkylenes such as polyoxyethylene having at least 2 ethylene units, polyoxypropylene having at least 2 propylene units, or copolymers thereof. Suitable polydiorganosiloxanes include the polydiorganosiloxane diamines of Formula 1, which are described above, minus the two amino groups. Exemplary polydiorganosiloxanes include, but are not limited to, polydimethylsiloxanes with alkylene Y groups. Suitable aralkylene groups usually contain an arylene group having 6 to 12 carbon atoms bonded to an alkylene group having 1 to 10 carbon atoms. Some exemplary aralkylene groups are phenylene-alkylene where the phenylene is bonded to an alkylene having 1 to 10 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. As used herein with reference to group G, “a combination thereof’ refers to a combination of two or more groups selected from an alkylene, heteroalkylene, polydiorganosiloxane, arylene, and aralkylene. A combination can be, for example, an aralkylene bonded to an alkylene (e.g., alkylene-arylene-alkylene). In one exemplary alkylene-arylene-alkylene combination, the arylene is phenylene and each alkylene has 1 to 10, 1 to 6, or 1 to 4 carbon atoms.

The polydiorganosiloxane polyoxamide tends to be free of groups having a formula -R^a-(CO)-NH- where R^a is an alkylene. All of the carbonylamino groups along the backbone of the copolymeric material are part of an oxalylamino group (i.e., the -(CO)-(CO)-NH- group). That is, any carbonyl group along the backbone of the copolymeric material is bonded to another carbonyl group and is part of an oxalyl group. More specifically, the polydiorganosiloxane polyoxamide has a plurality of aminoxalylamino groups.

Another useful class of elastomeric siloxane polymers is amide-based polysiloxane polymers. Such polymers are similar to the urea-based polymers, containing amide linkages (-N(D)-C(O)-) instead of urea linkages (-N(D)-C(O)-N(D)-), where C(O) represents a carbonyl group and D is a hydrogen or alkyl group.

Another example of a useful class of elastomeric siloxane polymers is urethane-based siloxane polymers such as siloxane polyurea-urethane block copolymers. Siloxane polyurea-urethane block copolymers include the reaction product of a polydiorganosiloxane diamine (also referred to as siloxane diamine), a diisocyanate, and an organic polyol. Such materials are structurally very similar to the structure of Formula I except that the -N(D)-B-N(D)- links are replaced by -O-B-O- links. Examples of such polymers are described, for example, in US Patent No. 5,214,119.

The silicone materials comprising a siloxane backbone optionally in combination with other moieties may be oils, fluids, gums, elastomers, or resins, e.g., friable solid resins. Lower molecular weight, lower viscosity materials are referred to as fluids or oils, while higher molecular weight, higher viscosity materials are referred to as gums; however, there is no sharp distinction between these terms. Silicone oils are commercially available (e.g. from Wacker) at viscosities from 0.65 to 1,000,000 mPa«sec at 25 °C. In typical embodiments, higher viscosity (e.g. non-functional) liquid polydiorganosiloxanes are preferred. In some embodiments, the liquid polydiorganosiloxane has a viscosity of at least 50,000; 100,000; 250,000; 500,000; 750,000; or 1,000,000 mPa’sec at 25 °C. When polydiorganosiloxane gum is utilized, the viscosity may be greater than 1,000,000 mPa«sec at 25 °C.

In some embodiments, the silicone adhesive further comprise a silicate tackifying resin. Suitable silicate tackifying resins include those resins composed of the following structural units M (i.e., monovalent R^SiO^^ units), D (i.e., divalent R^SiCfy^ units), T (i.e., trivalent R'SiC>3/2 units), and Q (i.e., quaternary SiOq/2 units), and combinations thereof. Typical exemplary silicate resins include MQ silicate tackifying resins, MQD silicate tackifying resins, and MQT silicate tackifying resins. These silicate tackifying resins usually have a number average molecular weight in the range of 100 to 50,000- gm/mole, e.g., 500 to 15,000 gm/mole and generally R' groups are methyl groups.

MQ silicate tackifying resins are copolymeric resins where each M unit is bonded to a Q unit, and each Q unit is bonded to at least one other Q unit. Some of the Q units are bonded to only other Q units. However, some Q units are bonded to hydroxyl radicals resulting in HOSiC>3/2 units (i.e., "T^H" units), thereby accounting for some silicon-bonded hydroxyl content of the silicate tackifying resin.

The amount of silicon bonded hydroxyl groups (i.e., silanol) on the MQ resin may be reduced to no greater than 1.5 weight percent, no greater than 1.2 weight percent, no greater than 1.0 weight percent, or no greater than 0.8 weight percent based on the weight of the silicate tackifying resin. This may be accomplished, for example, by reacting hexamethyldisilazane with the silicate tackifying resin. Such a reaction may be catalyzed, for example, with trifluoroacetic acid. Alternatively, trimethylchlorosilane or trimethylsilylacetamide may be reacted with the silicate tackifying resin, a catalyst not being necessary in this case.

MQD silicone tackifying resins are terpolymers having M, Q and D units. In some embodiments, some of the methyl R' groups of the D units can be replaced with vinyl (CH2=CH-) groups ("D^¹" units). MQT silicate tackifying resins are terpolymers having M, Q and T units.

Suitable silicate tackifying resins are commercially available from sources such as Dow Coming (e.g., DC 2-7066), Momentive Performance Materials (e.g., SR545 and SR1000), and Wacker Chemie AG (e.g., BELSIL TMS-803).

In some embodiments, the layer of polydiorganosiloxane composition comprises (e.g. silicate) tackifying resin in an amount of at least 5, 10, 15, 20, 25, 30 wt.% or greater of the total silicone adhesive composition.

The average release force and readhesion of the release layer can be evaluated according to the test methods described in the examples.

In some embodiments, the average initial release force of the release layer can generally range from 5 g/inch (2.54cm) to 800 g/inch (11.16 to 167.4 g/cm) at a peel rate of 60 inches (152 cm)/min. The average initial release force is typically report after aging at 50°C for 1, 2, 5, 7, 8, or 19 days. In some embodiments, the average initial release force of the release coating is at least 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 g/inch. A higher average initial release force can be preferred in some embodiments to prevent a roll of tape from self-unwinding or to provide greater holding power when over taping occurs such as for packaging tape and medical tape.

In some embodiments, such as industrial silicone adhesive articles, the release layer may provide an average initial release force of at least 500, 600, 700, or 800 g/inch. In other embodiments, the average release force is no greater than 500, 400, 300, 200, 100, or 50 g/inch. The readhesion can generally range from 25-500 g/inch after 1, 3 or 13 days of aging at 50°C. In some embodiments, the readhesion is at least 50 or 100 g/inch. In some embodiments, the readhesion is not greater than 400, 300, 200, or 100 g/inch. Low readhesion value can be indicative of transfer of the release layer or release compound onto the adhesive surface.

The invention is illustrated by the following examples.

Table 1 - Materials List

Contact Angle Measurements

Contact angle measurements were made on the coating samples obtained after drying. Measurements were made using as-received reagent-grade hexadecane (Aldrich), diiodomethane (Aldrich), DMS-14 obtained from Gelest, Morrisville, Pennsylvania and deionized water filtered through a filtration system obtained from Millipore Corporation (Billerica, MA), on a video contact angle analyzer available as product number VCA-2500XE from AST Products (Billerica, MA). Reported values were the averages of measurements on at least three drops measured on the right and the left sides of the drops and are shown in Tables. Drop volumes were 5 mL for static measurements.

Peel Testing

Peel testing was performed using an iMass TL-2300 Peel Tester. Average data was collected using DataLink software. The method used had the following instrument-set conditions: Initial Delay: 2 seconds, Averaging Time: 5 seconds, Test Time (Platen Stop Mode), Force Units: grams Speed Units: in/min, Testing Speed: 60 in/min - 152.4 cm/min. The release liner (coated substrate or film) to be tested was adhered onto the instrument sled, near the force meter, with tape on the ends keeping it flat to avoid friction with the force probe testing clamp. The force probe was lined up even with each piece of tape and attached with the force testing clamp. The sled was manually jogged away from the probe to remove any slack before performing the test. The release liner was cooled to RT and hand laminated to the adhesive surface of tape (e.g. 3M 8403 or Scotch Magic tape) and placed into a forced air oven to age at 50°C for the indicated number of days. After aging, the samples were conditioned at room temperature for at least 1 hour. The peel force measurements were conducted at room temperature.

Re-adhesion Testing

For re-adhesion testing, adhesion of the tape to glass substrate, pre-cleaned with isopropanol, and comparing against the control 3M 8403 tape for peel force is conducted. Conditions are similar to the Peel Testing method with the exceptions of the peel speed set to 12 in/min and data collection with 20 seconds of averaging time. When SPU or rSPOx PSAs were used, the adhesive on backing was removed from the release liner, laminated to a 1” wide piece of primed PET, removed from its backing, and laminated to cleaned glass. The readhesion force was measured by peeling the PET with adhesive from the glass at 12 in/min. Certain peel tests were also conducted at 1200 in/min to determine speeddependence of peel force using the example formulations.

Melting Point Determination

Melting points of the release additives were measured by a dynamic scanning calorimeter (DSC instrument), TA Instruments Q2000, using a temperature ramp from room temperature to 200°C at 10 C/min, cooling at 5°C/min to 0°C, followed by a second heat to 200°C (or greater) at 10°C/min.

Preparation of Release Compounds With Urethane Linking Group

MDI-n-butyl (C4MDIC4)

Into a 100ml one-neck round bottle flask was place a stirring bar, methylene diphenyldiisocyanate (25.0g, mw=250.25) and n-butanol (14.9g, mw=74.12). They were mixed neat and heated up to 100-110C. The diisocyanate was melted into a liquid and quickly underwent a reaction with the alcohol to give a white solid. The reaction mixture was heated until the solid melted into a liquid and until no reflux from the liquid was observable to make sure that all the alcohol was consumed. ATR-IR measurement of the solid indicated complete consumption of the isocyanate groups. Melting point by DSC has onset at 98.7°C and maximum at 109.7°C on first heat.

C6MDIC6

To a dry 250 mL Schlenk flask, 23.35 g MDI was charged under argon. 23.5 mL 1-hexanol was added dropwise over 3 minutes while stirring the mixture with a PTFE-clad magnetic stirbar. An exotherm was observed raising the temperature to 96.7 °C over 15 minutes. Mixture solidified and was further heated above melting point to 140°C over 30 minutes with a heating mantle. Upon cooling, crystals were observed forming at 109°C. A sample was analyzed by ATR-IR and no isocyanate group band remained. Recovered 41.97 g without further purification. Melting point by DSC has onset at 95°C and maximum at 108.9°C on first heat.

C8MDIC8

Into a round bottle flask was placed 25.02g of MDI (mw=250.25) solid and 26.05g of 1-octanol (mw=130.2). The flask was assembled with a water condenser with a nitrogen inlet. The mixture was heated to around 80-100°C and the solution became a clear liquid. The solution was allowed to heat for another hour until all the alcohol was consumed. The solution was cooled to room temperature and the product became solidified. Its IR spectrum showed complete disappearance of isocyanate group band. Melting point by DSC has onset of endotherm at 111°C and maximum at 121°C on first heat.

C10MDIC10

Into a 100ml one-neck round bottle flask was place a stirring bar, methylene diphenyldiisocyanate (12.51g, mw=250.25) and 1-decanol (15.83g, mw=158.28). They were mixed neat and heated up to 100- 110C. The diisocyanate was melted into a liquid and quickly underwent a reaction with the alcohol to give a white solid. To the reaction mixture was add 25mL toluene solvent and it was heated until all the solid dissolved into the toluene and allowed to cool to recrystallize, thus completing the reaction. Toluene was removed to give a 100% yield. Melting point by DSC has onset of endotherm at 120.1°C and maximum at 124.4°C on first heat.

C12MDIC12

To a dry 250 mL Schlenk flask under argon, added 36.747 g 1-dodecanol, 24.67 g MDI, and a magnetic stirbar. Began heating over 80°C mantle at 50%/120V with Variac. Rapid exotherm to 124 C was observed and product began to solidify. Heating further to 136°C remelted the mixture to allow continued agitation and further heating to 150°C over 25 minutes before cooling slowly at room temperature. After one hour of cooling, solid mass was sampled and analyzed by ATR-IR which showed disappearance of isocyanate band. Solids were broken up and collected without further purification with a 60.54 g (98.6%) yield after transfers. Melting point by DSC has onset of endotherm at 121.1°C and maximum at 127.9 °C on first heat.

C18MDIC18

C18-MDI-C 8 - diurethane

To a IL dry Schlenk flask under argon was added 20.2 g MDI, 500 mL dry DCM, and a magnetic stirbar. Mixture was stirred at 30°C over an oil bath to dissolve MDI. Solution was filtered into a 3-neck RBF through cannula filter and brought to 35 C. RBF was fitted with a condenser under argon, a thermocouple through a septum, and 43.71 g 1 -octadecanol was charged to the reactor in small increments. After addition of half the alcohol over 9 minutes, 3 drops neat dibutyltin dilaurate was added with observable exotherm. Added remainder of alcohol in a single addition with an additional 250 mL dry DCM to aide agitation by stirbar and solution was refluxed for 2.5 h before sampling slurry. Sample was vacuum dried at 40 °C, 10 mbar to achieve a white solid that was analyzed by ATR-IR and found to have no isocyanate group band remaining. All solids were vacuum filtered over a nonwoven supported by glass frit, rinsing with fresh DCM to obtain white powder that was further rotavapped in ajar. Obtained 62.25 g solid white powder. Recrystallized at approximately 25 wt% in THF by gently heating until dissolved and cooling at room temperature overnight. Crystalline solids were vacuum filtered and vacuum dried to 9 mbar at 40°C by rotary evaporator and further to 90 mtorr at room temperature under dynamic vacuum on a high vacuum line to collect 56.22 g (88.7% yield) white crystalline solids. Melting point by DSC has onset of endotherm at 127.9°C and maximum at 131.9°C on first heat.

ODI-BPF-ODI

001 - B P F- OD I d i ure tha ne tso mer

To a dry 100 mL round bottom flask under nitrogen was added 5.0 g Bisphenol F, magnetic stirbar and 14.8 g stearyl isocyanate which had been filtered through 1 um glass microfiber filter. Fitted flask with a heating mantle and stirred to homogenous slurry. Heated to 197°C over 1 hour and cooled to 78 C. After sampling, added 3 drops of dibutyl tin and heated to 165.2°C over 40 minutes and cooled to a solid. Sampled, then reheated mixture to 182.6 C over an hour and cooled to room temperature. The solid mass was sampled and analyzed by ATR-IR which showed disappearance of isocyanate band. A small amount of product was dissolved into THF at 5 wt% at 55°C and recrystallized at room temperature over 2 hours. Recrystallized sample was recovered at 80.3% after vacuum filtering and drying under high vac. Melting point of recrystallized material by DSC has onset of endotherm at 128.5°C and maximum at 142.4°C on first heat. rt-BuPhMDIPh/?-Bu

Into a round bottle flask was placed 3.57g of MDI (mw=250.25, a solid) and 4.3g of 4-n-butylphenol (mw=150.22). The flask was assembled with a water condenser connected with a nitrogen inlet. The mixture was heated to around 80-120°C and the solution became a clear liquid. The solution was allowed to heat for another hour until all the alcohol was consumed. The solution was cooled to room temperature and the product became solidified. Its IR spectrum showed complete disappearance of isocyanate group band. Melting point by DSC has two endotherms with maxima at 140.0°C and 155.4°C on first heat, during the cool a single exotherm with maximum at 124.6°C, and during the second heat a single endotherm with onset at about 118°C and maximum at 136.0°C was observed.

Preparation of Release Lavers Comprising Organic Polymer and Release Compounds

General coating solution preparation procedure

The organic polymers were separately mixed with the indicated solvent to prepare organic polymer solutions having the wt.% solids described in the tables. The polymer and solvent were placed in a container and rolled at a speed of 80cycles/min. overnight to obtain stable polymeric solutions.

The indicated release compound (i.e. additive) was added to the organic polymer solutions at the amounts described in the table and vortexed at high speed for a minute to form homogenous solutions. The coating solutions were heated to ensure that all the additives were completely dissolved in each of the polymeric solutions. Method of Applying Coating Solutions to Substrate

Drawdown coatings were manually coated by applying coating solution to a substrate, (e.g., PET, PCK) and pulling the solution down the substrate using a Meyer Rod or 4” milled/notched square (Gardco) at fixed (1-8 mil) gap heights. PET and other hard substrates were taped to a flat surface for drawdown coating but soft/deformable substrates like PCK were placed upon a vacuum plate to flatten the coating for uniform coatings when subjected to the weight of the coating square. Drying conditions varied and are described in the tables.

Method of Automated Coating Utilized for Examples of Tables 2B, 5, 7 and 8

The coating solution were supplied to a 4 inch (10.2 cm) wide slot type coating die, onto a 6 inch (15.2 cm) wide PCK web moving at a speed of 5 ft/min (1.52 m/min). The solution delivery rate was adjusted to achieve the dry coating thickness for each example listed in the tables below. The coated web then travelled approximately 13 ft (4 m) before entering a 30 ft (9.14 m) conventional air floatation drier with 3 independently controlled zones having a length of 10 ft (3.05 m). The oven zone temperatures of each sample are provided in the tables below.

Table 1 - Release Layers with Additive (R1 and R2 = C4, C6, C8)

4 mil Gap Size (Dried Coating Thickness 1.25 to 2.5 microns) , Dried 120°C for 1.5 minutes. Samples were evaluated with 3M 8403.

Table 2A - Release Layers with Additive (R1 and R2 = CIO, C12, C18)

4 mil Gap Size applied to PCK Glossy Substrate. Samples were evaluated with 3M 8403,

Table 2B - Release Layers with ODI-BPF-ODI

Applied to PCK, Glossy Substrate. Samples were evaluated with 3M 8403.

The contact angle of samples prepared with a 4 mil gap size applied to PCK Substrate was evaluated, as reported in the following tables:

Table 3 - Contact angles measured using diiodomethane as the testing fluid

Dried at 120°C

Table 4 - Contact angles measured using n-hexadecane as the testing fluid

Table 5 - Contact angles measured using DMS as the testing fluid

Table 6 - Release Layers with Styrenic Block Copolymers

10 wt.% Polymer Solutions Dried at 120°C for indicated time. Samples were evaluated with 3M 8403.

4 mil gap = 1.5 - 3 microns dried coating, 2 mil gap = 0.75 - 1.5 micron dried coating Table 7 - Release Layers with Styrenic Block Copolymers and PET Substrate Samples were evaluated with Magic Tape

Table 8 - Release Layers with Styrenic Block Copolymers and Polystyrene Aged 1 day at 50°C

CP = cyclopentanone Table 9 - Release Layers with Styrenic Block Copolymers and Ethylene-Propylene Copolymer

Table 10 - Release Layers with Acrylic Polymer

Samples were evaluated with 3M8403Tape after 1 Day of Aging at 50°C

Table 11 - Release Layer with BuPhMDIPhBu

Dried at 120°C for 3 minutes. Samples were evaluated with 3M8403Tape after 1 Day of Aging at 50°C

Table 12 - Coating Solution Stability after 1 hour

Stable means that the solution is clear or has formed a coatable stable suspension for more than an hour. Thermal Extrusion Examples

Polypropylene (PP1024) or polyester (PETGN071) was compounded with finely powdered C18MDIC18 release additive at different levels and extruded via a Thermo Scientific Process 11 Parallel Twin-screw Extruder into films with 1 to 1.5” wide and 10 mil in thickness. The polypropylene or polyester pellets and the release additive were fed at 2.2 Ibs/hr and extruded with 18mm twin screw extruder equipped with two feeders through the initial zone temperature at 170°C to the final temperature at 200°C under 300RPM. The extmded fdms were further heat-treated at 120°C for 3 min. Both major surfaces (inside and outside) of the resulting extruded films were laminated with 3M 8403 tape, and the resulting laminated samples were aged at 50°C for 48 hrs. The final samples were subjected to release peel test. The results were summarized.

Table 13 - Thermal Extrusion Examples

Table 14 - X-ray photoelectron Spectroscopy (XPS) Analysis

The following examples were obtained from the automated coating procedure as described above.

The sample surfaces were examined using X-ray Photoelectron Spectroscopy (XPS) also known as Electron Spectroscopy for Chemical Analysis (ESCA) using the analysis parameters described below. This technique provides an analysis of the outermost 3 to 10 nanometers (nm) on the specimen surface. The photoelectron spectra provide information about the elemental and chemical (oxidation state and/or functional group) concentrations present on a solid surface. It is sensitive to all elements in the periodic table except hydrogen and helium with detection limits for most species in the 0.1 to 1 atomic % concentration range.

If the surface had 100% of the release compound, the concentration of nitrogen would be 3.39.

Thus, the results show that the release compound is concentrated at the surface.

C18MDIC18 and ODI-BPF-ODI were analyzed by Proton Nuclear Magnetic Resonance t'H-NMR) by dissolving a sample in deuterated DMSO in an NMR tube in a 120 °C heat block, placing into a ceramic spinner of a Broker Avance III HD NMR Spectrometer with a Bmker 5mm TCI inverse probe, heating the probe to the set temperature, allowing 10 minutes for temperature equilibration, collect 1H NMR scans, then adjusting temperature to the next set point and collecting data in the same manner.

The chemical shifts of the proton signals of the urethane groups of C18MDIC18 shifted from 9.15 to 9.42 ppm and the signals narrowed as the temperature decreased from 100°C to 25°C.

ODI-BPF-ODI had chemical shifts of the proton signals at 9.11, 9.05 and at 7.65 ppm at 25°C. The 7.65 ppm proton peak is attributed to molecule free of H-bond. The chemical shifts of the proton signals of the urethane groups of ODI-BPF-ODI shifted from about 8.75 to 9.15 and 9.05 ppm and the signals narrowed as the temperature decreased from 100°C to 25°C.

For both compounds, the signals of the aromatic proton of phenyl at high field (shielding effect) became weaker, and those signals at low field were stronger. These results indicate that these compounds have a self-assembled structure stabilized by hydrogen-bonding and minorly contributed by K-K- stacking interactions in the gel phase.

Infrared spectroscopy was conducted using a Nicolet 6700 FTIR with Pike GladiATR heated stage with a diamond ATR crystal, compressing the sample against the crystal with an anvil, and acquiring 16 scans from 4000-400 cm'¹ at 4 cm'¹ resolution, as depicted in Figs 4 and 5. Sample scans were collected at ambient conditions, then heated to about 165 °C, collecting scans, then cooling to about 120 °C, collecting another set of scans, and reheating to about 130-140 C to collect a final set of scans, as depicted in Figs 4 and 5. Notably there is a peak absorbance having a peak height between 0.05 and 0.13 within a wavelength range of 3250 and 3400 nm at room temperature. Such peak absorbance is also present after two melting and cooling cycles. This is indicative of the thermal stability of the compound.

Additional Thermal Extrusion Examples

Thermoplastic polymers and release agents were fed from separate feeders into the extruder hopper at designated feed rates to achieve various release agent concentrations (as indicated in the tables) and/or polymer mixtures. The compositions were subsequently mixed and heated through temperature- controlled zones of a twin-screw extruder. For LDPE, LDPE/878P blends, and PP the temperature of the zones was increased from 375°F to 520°F. For the PTA Clear 62/PCTg blends, the temperature of the zones was increased from 400°F to 520°F. The die temperature was 530°F. The polymer mixture was fed through a die onto a cast wheel (temperature was 80°F) with varied speed depending on the desired coating or film thickness. In some examples, a PCK or PET liner, as indicated in the example tables, was threaded up inline over the cast wheel so the film was extruded directly onto the liner. Single and double-sided release liners were prepared by extruding the compositions onto PCK and PET substrates. In double-sided extrusion coated examples, the single-pass extrusion liner was flipped so the 1^st side contacted the cast wheel and the next composition was extruded onto the uncoated side of the liner. The liner contact time on the cast wheel was short (seconds).

The extruded release composition had a thickness of about 1 mil (25 microns) unless specified otherwise. When subsequent heat treatment was conducted, the time and temperature is specific in the table. The results are as follows.

Table 15 - Control extruded coatings and free standing films without release agent were prepared, laminated with 3M 8403 tape, aged overnight at 50°C.

Table 16 - Extruded coatings of C18MDIC18 in NA217000 LDPE, 2-5 microns thick on PCK tested with 3M 8403 tape

The data showing that heat treatment processes can be utilized to adjust the average release values.

Table 17 - Extruded coatings (about 1 mil) of C18MDIC18 in 75/25 LDPE/878P EPM blends on PCK tested with 3M 8403 tape.

Table 18 - Extruded coatings (about 1 mil) of C18MDIC18 in 75/25 LDPE/878P EPM blends tested with solvent-casted SPU adhesive after aging overnight at 50 C.

Table 19 - Extruded coatings (about 1 mil) of C18MDIC18 in Polypropylene (Profax SR549) on PCK tested with 3M 8403.

Crosslinked Organic Polymers

Table 20A - Two-part compositions were prepared by dissolving MDI (15.02 g) and CAPA 3031 (18 g) monomers in THF (218.7g) and a separate solution in (1:1 toluene :cyclopentanone w/w). Another solution was prepared by addition of Desmodur N3390 (30.6 g) and CAPA 3031 (18 g) in toluene (437.2 g) and THF (50.0 g). In the first example below, the solutions were combined (10 g each at a 1 : 1 weight ratio) and coated after adding and mixing in a drop of dibutlytin dilaurate (50wt% in THF). In the second example, the MDI/CAPA solution from toluene/cyclopentanone was coated after adding and mixing in a drop of dibutyltin dilaurate (50 wt% in THF). Coatings were prepared on PET at a 6 mil wet gap. Wet coatings were dried at 140°C for 15 minutes in a forced air oven on an aluminum pan during which the MDI and CAPA reacted forming a polyurethane. Dried samples were aged in a forced air oven. Samples were evaluated with 3M 8403.

Table 20B - Two-part compositions were prepared by addition of Desmodur N3390 (30.6 g) and CAPA 3031 (18 g) in toluene (437.2 g) and THF (50.0 g). The solutions were coated after adding and mixing in a drop of dibutlytin dilaurate (50 wt% in THF) to about 20 g of coating solution. Coatings were prepared on the glossy side of PCK at a 5 mil wet gap. Wet coatings were dried at 120°C for 15 minutes in a forced air oven on an aluminum pan during which the Desmodur and CAPA reacted forming a polyurethane. Dried samples were aged in a forced air oven. Samples were evaluated with 3M 8403.

Table 21 - 5 wt.% solution of 3110M with 3 pph (based on the amount of 3110M) of C18MDIC18 in 85/15 toluene/IPA organic solvent on PET and PCK substrates after aging laminated 3M 8403 tape overnight at 50°C.

Table 22 - 10 wt.% solution of DI 102 SBS with 3 pph (based on the amount of DI 102) of C18MDIC18, coating thickness of 4 mils on PET and PCK substrates after aging laminated 3M 8403 tape overnight at 50°C.

Table 23 - 10 wt.% solution of DI 102 SBS with 3 pph (based on the amount of DI 102) of C18MDIC18 in 80/20 toluene/IPA organic solvent tested with solvent-coated SPU adhesive.

Table 24 - Contact angle measurements of D 1102 Release Coatings

Table 25A - Ultraviolet Radiation Cured DI 102 SBS

10 wt.% DI 102 dissolved in organic solvent (80/20 toluene IP A) coated at a thickness of 4 microns on PET and PCK substrates after aging laminated 3M 8403 tape overnight at 50°C. The dried coating (about 0.4 microns) was cured with 4 passes with an H bulb utilizing a nitrogen-inerted Heraeus DRS 6 1100N conveyor system with Light Hammer 6 UV source by Fusion UV Systems, Inc.

Table 25B

D1102 with C18MDIC18 - Crosslinked vs Not Crosslinked

A solution of DI 102 SBS was prepared at 10 wt.% in 80/20 Toluene IPA with heat and agitation al 80°C until dissolved. Room temperature solution was split and mixed with only C18MDIC18 at 3 pphr or with C18MDIC18 at 3 pphr, 2 pphr PETMP and 2 pphr ACHN. Solutions were heated at 65°C in a block heater with occasional agitation until Gloss. 1 g sample aliquots were added to 4 oz jars and dried in forced air oven at 120°C for 40 minutes. Dry samples were peeled from the bottom of the jars and added to vials to be completely submerged in 20 g 80/20 Toluene/IPA (w/w) at room temperature.

The samples with C18MDIC18 and no crosslinking agents (about 5 wt.% solids solution) completely lost film structure within 10 minutes and completely dissolved with further mild agitation. The samples with C18MDIC18, PETMP, and ACHN maintained film structure even after 24 h and did not dissolve with mild agitation.

Claims

What is claimed is:

1. An adhesive article comprising: a substrate; a release layer comprising an organic polymer and a release compound disposed on the substrate; wherein the release compound has the formula:

wherein

X is -CH₂-;

L is a divalent linking group comprising a urethane moiety; and

R1 and R2 independently comprise a C4-C30 hydrocarbon group; and an adhesive bonded to the release layer.

2. The adhesive article of claim 1 wherein R1 or R2 independently comprises at least 10 or 12 carbon atoms.

3. The adhesive article of claim 1 wherein R1 or R2 comprises at least 18 carbon atoms.

4. The adhesive article of claim 1-3 wherein the release compound has the formula

5. The adhesive article of claim 1-3 wherein the release compound has the formula

6. The adhesive article of claims 1-5 wherein the release layer comprises 0.5 to 10 wt.% of the release compound.

7. The adhesive article of claims 1-6 wherein the release layer comprises a first major surface proximate the substrate and a second major surface proximate the adhesive wherein the second surface comprises a greater concentration of the release compound than the first major surface.

8. The adhesive article of claims 1-7 wherein the organic polymer has a melting temperature or glass transition temperature in the range of 150°C-450°C.

9. The adhesive article of claims 1-8 wherein the organic polymer is soluble at a concentration of 10 wt.% in an organic solvent selected from tetrahydrofuran, 2-methyltetrahydrofuran, toluene, cyclopentanone, 2-butanone, xylenes, 2-propanol, n-propanol, methanol, and mixtures thereof.

10. The adhesive article of claims 1-9 wherein the release compound is soluble or dispersible at a concentration of 10 wt.% in an organic solvent selected from tetrahydrofuran, 2-methyltetrahydrofuran, toluene, cyclopentanone, 2-butanone, xylenes, 2-propanol, n-propanol, methanol, and mixtures thereof.

11. The adhesive article of claims 1-10 wherein the organic polymer is amorphous.

12. The adhesive article of claims 1-11 wherein the organic polymer comprises a polyolefin polymer.

13. The adhesive article of claims 1-12 wherein the release compound has a melt temperature in the range of 95-150°C.

14. The adhesive article of claims 1-13 wherein the substrate comprises an organic polymer, paper, or a combination thereof.

15. The adhesive article of claims 1-14 wherein the release layer has a static contact angle property selected from: a) a static contact angle with diiodomethane of 45 to 85 degrees; b) a static contact angle with n-hexadecane of 35 to 55 degrees; and c) a static contact angle with dimethylsiloxane of 20 to 40 degrees.

16. The adhesive article of claims 1-15 wherein the adhesive is a pressure sensitive adhesive.

17. The adhesive article of claims 1-16 wherein the adhesive is a silicone-based adhesive.

18. The adhesive article of claims 1-17 wherein the adhesive exhibits a peel adhesion to the release layer of at least 25% less than peel adhesion to the substrate lacking the release layer.

19. The adhesive article of claims 1-18 wherein the release compounds form molecular assembled structures.

20. The adhesive article of claims 1-19 wherein the organic polymer comprises unsaturated groups.

21. The adhesive article of claim 20 wherein the unsaturated groups are alkene or alkenyl groups.

22. The adhesive article of claims 1-21 wherein the organic polymer is a polyurethane.

23. The adhesive article of claim 22 wherein the polyurethane is a reaction product of a polyisocyanate and/or a polyol comprising at least three isocyanate and/or -OH groups.

24. The adhesive article of claims 1-23 wherein the organic polymer is crosslinked.

25. The adhesive article of claim 23 wherein the organic polymer is crosslinked with a chemical crosslinking agent or crosslinked by exposure to actinic radiation.

26. The adhesive article of claims 24-25 wherein the crosslinked organic polymer is insoluble in organic solvent at a concentration ranging from 5 to 10 wt.% solids.

27. The adhesive article comprising release coatings disposed on both major surfaces of substrate and at least one release coating is the release coatings is the release layer of claims 1-26.

28. A release liner article comprising: a substrate; a release layer comprising a release compound disposed on the substrate; wherein the release compound has the formula:

wherein

X is -CH₂-;

L is a divalent linking group comprising a urethane moiety; and

R1 and R2 independently comprise a C4-C30 hydrocarbon group.

29. The release liner article of claim 19 wherein the release layer further comprises an organic polymer.

30. The release liner of claims 28-29 wherein the release layer is further characterized by claims 2-27.

31. A composition comprising an organic polymer and a compound having the formula:

wherein

X is -CH₂-;

L is a divalent linking group comprising a urethane moiety; and

R1 and R2 independently comprise a C4-C30 hydrocarbon group.

32. The composition of claim 31 wherein the composition is further characterized by claims 2-27.

33. A film or film layer comprising the composition of claims 31-32 wherein the compound is uniformly distributed within the organic polymer or concentrated at a surface of the film or film layer.

34. A method of making a composition comprising: combining an organic polymer and a compound having the formula:

wherein L is a divalent linking group comprising a urethane moiety; and R1 and R2 are independently C4-C22 hydrocarbon groups.

35. The method of claim 34 further comprising applying the composition to a substrate.

36. The method of claims 34-35 wherein combining the organic polymer and the compound comprises forming a solution of the organic polymer, the compound and organic solvent.

37. The method of claims 34-36 wherein the organic solvent is selected from tetrahydrofuran, 2- methyltetrahydrofuran, toluene, cyclopentanone, 2-butanone, xylenes, 2-propanol, and mixtures thereof.

38. The method claims 34-37 further comprising removing the organic solvent(s).

39. The method claims 34-35 wherein combining and applying the organic polymer and the compound comprises thermal extrusion.

40. The method of claim 39 wherein the substrate is a thermoplastic organic polymer that is coextruded with the composition.

41. The method of claims 34-40 further characterized by claims 2-27.

42. The method of claims 35-41 comprising heat treating the applied organic polymer and compound.

43. The method of claims 34-42 further comprising exposing the applied organic polymer and compound to heat, actinic radiation, or a combination thereof to crosslink the organic polymer.