WO2000063269A1

WO2000063269A1 - Polyurethane foam cell opening agents and methods for making foam using the same

Info

Publication number: WO2000063269A1
Application number: PCT/US2000/007868
Authority: WO
Inventors: Tyler Housel; Robert C. Haupt
Original assignee: Inolex Investment Corp
Current assignee: Inolex Investment Corp
Priority date: 1999-04-19
Filing date: 2000-03-24
Publication date: 2000-10-26
Anticipated expiration: 2001-10-19
Also published as: AU4026900A

Abstract

Polyurethane foam formulations and methods for forming polyurethane foams demonstrating improved clickability, wettability and/or air permeability are included. The formulations and methods include use of a cell opening agent which is a monoester or a diester of a polyether monol or polyether polyol. The polyether monol or polyether polyol has a molecular weight Mw of from about 100 to about 2000 and the cell opening agent has a monofunctional or polyfunctional initiator having at least one etherification site.

Description

TITLE OF THE INVENTION Polyurethane Foam Cell Opening Agents And Methods For Making Foam Using the Same

BACKGROUND OF THE INVENTION Polyurethane foams are typically manufactured as a reaction product of a polyisocyanate and a polyol along with other reactive compounds such as water, or other blowing agents, glycols, diamines and others which may be added to impart specific handling or mechanical properties. Polyurethane properties may also be modified with additives such as fatty acids, catalysts, solvents, surfactants, blowing agents, stabilizers, colorants, fillers, viscosity modifiers, flame retardants, release agents, plasticizers and others. The polyols generally used in manufacturing polyurethanes are low molecular weight polymers such as polyethers, polyesters, polycarbonates, polyacrylics, melamine and polybutadiene polyols. Such foam- forming base polyols are generally provided with at least two (end-terminal) hydroxyl groups and may have further hydroxyl or acid functionality acquired by modification of the polyol during its manufacture.

Approximately 80-99% of a typical polyurethane foam formulation is made up of the three main reactive components, polyisocyanate, base polyol and water. Polyurethane foam manufacturers normally store these materials in large tanks and prefer to manufacture many different types of foam using a minimal number of types of bulk raw materials. Different grades of foam are formed by changing the machine conditions, changing the ratio of ingredients or by using various additives. Additives are used to control things such as reaction rate, cell size, cell uniformity, color, flame retardance, density, hardness, flexibility and numerous other properties and characteristics of such foams.

Polyurethane foams are used for many purposes, including insulation, packing, and the like. A significant amount of polyurethane foam is used in applications in which the foam is processed by die cutting. In this technique, a slab of foam, typically up to about 3 inches thick is placed into a press under a razor-edged die. The press pushes the die through the foam to cut a pattern out of the foam. If the foam cuts cleanly and evenly, and the edges of the cut are completely unpinched (leaving a clean edge without the appearance of a pinched seam), the foam is referred to as "clickable." Typically die cut foam items include packaging, technical and novelty foams. Delicate items such as electronics, optical equipment, and the like are often packaged in such a way that they are cushioned by die cut foam. The foam can be cut to the exact shape and size of the parts to be packaged and to hold them firmly in place. For example, a camera case may have different cut-out shapes to fit the camera, several lenses, film, batteries and other accessories. This keeps the pieces organized and prevents them from damaging each other or otherwise being damaged in transit. Technical foams are small, specialized pieces of foam useful for a variety of specific applications. Novelty foams include sponges, promotional items, toy weapons, animals and the like. Often, these are die cut because it is an easy and inexpensive way to make a small number of parts quickly with an excellent aesthetic appearance.

A great deal of foams are "non-clickable" foams which are not intended for die cut applications, and may partially crimp at the edges if attempting a die cut. Clickability is not important for foam used, for example, in laminates or textile applications because the foam will be processed in a different manner. Non-clickable foams are easier to manufacture, so clickable foams are only produced when necessary.

Extremely non-clickable foams are referred to as "edge-weldable" foams. This means that the foam will be permanently sealed around the edge if crimped in a press. These types of foams are occasionally produced for specific markets such as wax applicators where unsealed edges can tear. Ideally, clickability would be controlled through additives and machine conditions, but experience has shown that clickable foams also require use of special polyols and isocyanates. This means that foam manufacturers must have additional bulk tanks to store the particular polyols and polyisocyanates required to make clickable foams. There is a need in the art for an additive which will allow foam manufacturers to use standard polyols and polyisocyanates for making clickable foams without storing special materials. Paraffin oil has been used in foam formulations as a clickability enhancing additive. However, it has several drawbacks in performance. For example, it is extremely defoaming, and can cause pinholing and collapse if not blended properly or if the amount exceeds the effective level in the formulation by only 0.1-0.2% of the total mass of ingredients. This sensitivity to defects causes many foam manufacturers to use the product at less than the optimal level.

The same equipment is normally used to make both clickable and non- clickable foams, but, as noted above, the raw materials are usually different. In particular, clickable foams are normally made using toluene diisocyanate-65 and a polyol having a relatively high crosslinking density and equivalent weight. In addition, clickable foams are usually made with an open, coarse cell structure and/or may use special surfactants and catalysts. Further, thermal degradation can affect clickability, and sometimes blocks of foam can exhibit variable clickability throughout their block since different areas of the block encounter different exothermic temperature profiles. Despite the use of special formulations and ingredients, manufacturers still encounter difficulties in producing foams that meet desired clickability properties and requirements in an inexpensive and reproducible manner. For these reasons, and the others noted above, there is a need in the art for an additive which can be provided to foam formulations which allows use of standard foam ingredients to make clickable foams with consistent properties and with adequate control of clickability.

More specifically, in making clickable foams there are several differences with respect to the primary components and characteristics associated with making non-clickable foam. For example, formation of clickable foams is usually associated with use toluene diisocyanate having 65% of the 2,4 isomer (TDI-65), whereas non-clickable foams typically use toluene diisocyanate having 80% of the 2,4 isomer (TDI-80). While a polyester polyol having a hydroxyl number of 60 and a functionality of 3 would be useful for forming clickable foam, non-clickable foams would typically use a polyester polyol of a lower hydroxyl number around 50 and a lower functionality. While organic surfactants are optional with non-clickable foams, they are important in forming clickable foams. Non-clickable foams sometimes include silicone surfactant without paraffin oil, and would generally not include silicone surfactants with paraffin oil. However, clickable foams are associated with use of silicone surfactants with paraffin oil as well as the use of N-coco morpholine catalyst which is generally not used in non-clickable foams. Clickable foams tend to have larger cells and a high air permeability overall in comparison with non-clickable foams. In addition to the clickability property, there is a need in the art for improved cell opening capability. When foam components are first mixed, an added surfactant functions to induce cell nucleation by lowering surface tension of the bulk liquid mixture. The number of nucleation sites determines cell size, so the foam cells will be too large or inconsistent if the additive interrupts the nucleation. As the foam rises, the cells must stay intact and discrete so the pressure of the evolving gas will expand the bubbles and make the foam rise. If the cell opening additive causes the bubbles to break or coalesce at this stage, the foam will collapse (if uniformly distributed) or give localized defects such as voids, pinholes, double cells or buckshot. As the cells are growing, the viscosity and molecular weight of the polymer phase are also increasing. When the foam gets to a maximum height, the cells rupture. Rising foam is supported by pneumatic pressure of the gas in the bubbles, but after the membranes burst, the polymer must have sufficient strength to continue to support the weight of the foam. The transition from pneumatic to mechanical support is critical or the following difficulties and/or defects can arise:

(1) if the polymer gels too quickly, the bubbles cannot rupture because the membranes are already elastic at full rise. When the foam cools, the pressure of the gas inside the bubbles drops, making the foam shrink;

(2) if the polymer gels too slowly, the foam will rise to a maximum height and settle back because the struts (the polymer support) are too weak to resist gravity after the gas pressure is released; and

(3) if the polymer in the struts is not sufficiently elastic to stretch as the foam rises, broken struts will propagate through the foam resulting in a tear. Of course, polymer elasticity, strength and viscosity are rapidly changing as the molecular weight increases, so the timing of these reactions is very important.

In view of the above difficulties, there is a need in the art for a cell opening additive, particularly in clickable foams, which can reduce elasticity of the membranes so they can burst without reducing elasticity of the struts. Most of the surface area is in the membrane, while most of the polymer is in the struts. Therefore, there is further a need for a cell opening agent which is surface active, yet does not interfere with cell nucleation. While all of the foregoing are reasonable assumptions of the interactions present during foam mixing, rise and cure, the system is too complex to use this model to actually predict which additives will be effective, and, unfortunately, this means that useful cell opening additives are only identified through trial and error, and are not typically indicative as a result of any particular reaction theory.

Another desirable characteristic for some types of foam is wettability. Polyurethane foam is a polymer which was formed around growing gas bubbles as discussed above. Although the bubbles eventually burst, the polymer takes up only 5% or less of the volume of the foam with the rest being air that fills an interconnected network of cells that were once gas bubbles. Water can fill the air space, and any piece of open-celled polyurethane foam can hold many times its dry weight in water if the air is mechanically forced out and water is allowed to fill the cells.

As it relates to evaluation of foams formed in accordance with the present invention, wettability describes the ability of the foam to imbibe water without the need for mechanical assistance. This can be determined by adding a small drop of water on top of a cut piece of foam and measuring the time it takes for the water to absorb into the open voids of the foam. Most standard grades of polyurethane foam are considered hydrophobic, and a drop of water will bead on the surface of the foam for several minutes or hours before absorbing into the voids. Often, water will actually evaporate from the surface before it wets the foam. There are many types of flexible polyurethane foams that are manufactured expressly for the purpose of improving wettability. Wettability is an advantage if the foam is used for certain applications such as sponges, wipes, bandages, and applicators. These are typically made from non- standard polyols, isocyanates and other additives. Often, wettable foam has undesirable properties such as swelling and loss of strength when wet. There is a need in the art for a foam additive which can improve wettability without materially affecting the polymer matrix, and therefore has little effect on the size or strength of the foam between the wet and dry states.

BRIEF SUMMARY OF THE INVENTION The invention includes a polyurethane foam formulation, comprising a cell opening agent which is a monoester or a polyester of a polyether monol or a polyether polyol, wherein the polyether monol or polyether polyol has a molecular weight Mw of from about 100 to about 2000 and wherein the cell opening agent comprises a monofunctional or polyfunctional initiator having at least one etherification site.

In one embodiment the cell opening agent in the polyurethane foam formulation has the formula (I):

wherein P is a monofunctional or polyfunctional initiator having at least one etherification site;

R is independently selected from the group consisting of hydrogen, and aliphatic hydrocarbons of from 1 to about 4 carbon atoms; 2 R is independently selected from the group consisting of saturated and unsaturated, linear hydrocarbons of from about 3 to about 25 carbon atoms, and saturated and unsaturated, branched hydrocarbons of from about 3 to about 25 carbon atoms;

X is independently selected from the group consisting of hydrogen and -C(O)R², wherein at least one X is -C(O)R²; m is from about 1 to about 10; and n is from about 1 to about 50.

The invention also includes a method for forming a polyurethane foam, comprising providing a cell opening agent to a base formulation to form a polyurethane foam formulation, and foaming the polyurethane foam formulation. The cell opening agent is a monoester or a polyester of a polyether monol or a polyether polyol, wherein the polyether monol or polyether polyol has a molecular weight Mw of from about 100 to about 2000, and comprises a monofunctional or polyfunctional initiator having at least one etherification site. A method for improving clickability, air permeability or wettability of a polyurethane foam is also within the scope of the invention. The method comprises forming a base formulation for forming a polyurethane foam; adding to the base formulation a cell opening agent which is a monoester or a polyester of a polyether monol or a polyether polyol, wherein the polyether monol or polyether polyol has a molecular weight Mw of from about 100 to about 2000, and which comprises a monofunctional or polyfunctional initiator having at least one etherification site; and foaming the formulation comprising the cell opening agent to form a polyurethane foam.

The invention further includes a polyurethane foam formulation which comprises a base formulation for forming a polyurethane foam, and a cell opening agent which is a monoester or a polyester of a polyether monol or a polyether polyol having a molecular weight Mw of from about 100 to about 2000, and which comprises a monofunctional or a polyfunctional initiator having at least one etherification site.

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a polyurethane foam formulation, a method for forming polyurethane foam, and a method for improving clickability, air permeability and/or wettability of a polyurethane foam.

The foam formulations derived from use of the cell opening agent of the present invention demonstrate improved clickability, improved air permeability and/or improved wettability in the resulting foams. The polyurethane formulations of the invention having the cell opening agent as described herein demonstrate excellent properties as clickable foams in particular, using standard polyurethane formulations. The base formulation may be any standard polyurethane foam formulation, which has the cell opening agent described herein, but is preferably a foam formulation for producing clickable foam. As a result of the invention, manufacturers need not store special raw materials to form clickable foams, but can adjust the properties of the foam by use of the additive, providing a cost effective and convenient method for forming clickable foams and/or foams with improved wettability and air permeability from standard base formulations.

As used herein the terms "polyol," "polyester" and "polyisocyanate" refer, respectively, to compounds having two or more -OH functional groups; two or more ester groups or linkages; and two or more isocyanate groups.

In addition, with respect to use of functionalized polyols such as acid functional polyols and/or hydroxy functional polyols, the following terms are defined as follows. As used herein "acid value" or "acid number" of a polyol having acid functional groups is determined by weighing a small sample, typically 2-10 g, of the polyol into a flask. A 1:1 mixture of ethanol and benzene is added to dissolve the polyol. If the resin does not readily dissolve, a small amount of acetone may be added. The solution is titrated with a standardized KOH and measured in units of mg KOH/g sample.

The "hydroxyl value," or "hydroxyl number" of a given polymeric polyol having hydroxy functional groups is defined by the following formula (II):

Hydroxyl Number = 56.100 (II)

Equivalent Weight

where the Equivalent Weight is the hydroxyl equivalent weight.

The polyurethane foam formulations of the present invention preferably include a polyurethane base formulation and a cell opening agent. The base formulation may be any generally acceptable polyurethane foam formulation based on a polyol, such as a polyester polyol and/or a polyether polyol as described below. In addition, the base formulation includes a polyisocyanate, and water and/or other blowing agents. The foam forms by reaction of the polyisocyanate and the polyol in the presence of water and/or any other blowing agents which provide gas to fill the cells. The foam may also include silicone and/or organic surfactants to stabilize the foam and catalysts to control the reaction rates of the foam forming reactions. Other optional additives are described further below. As noted in the Background section herein, the base components are relatively standard, and many different types of foams can be formed by varying the base polyol, but more commonly by varying the type and amount of the optional additives and the machine conditions while forming the foams.

The base polyol is preferably a polyester polyol or a polyether polyol. The polyol is generally the largest component in the polyurethane base formulation. Preferred polyols typically have molecular weights Mw between 1000 and 6000, an average of between 2 and 4 hydroxyl groups per molecule, and an acid value of from 0 to about 150. Commercial polyols are available and are generally described based on the nature of their repeating units such as ester or ether units. Various other specialty polyols having varied repeating units are also available, but not as commonly used. The polyols used may be standard commercially available polyols with minimal functionality as noted above, or otherwise functionalized. Polyols which may be used in the base formulation of the present invention can be provided with various degrees of hydroxyl functionality, acid functionality, and/or acid and hydroxyl values depending on desired end properties of the foam, and can be derived from the reaction of at least one polyol and at least one polycarboxylic acid, typically a dicarboxylic acid, with optional other possible reactants including polyanhydrides and/or components having at least two unhindered functional groups and at least one hindered carboxylic acid functional group as described in U.S. Patent No. 5,880,250, incorporated herein by reference in its entirety.

Functionalized polyols which are useful in the present invention may include not only reactive hydroxyl groups, but also reactive or neutralizable localized pendant carboxylic acid groups or pendant carboxylic acid groups situated throughout the backbone of the polymeric polyol. Hydroxyl groups on the polyols useful in the invention react with isocyanate groups of the polyisocyanates to produce polyurethanes which may themselves be functional.

The invention is largely described for exemplary purposes in terms of polyester polyols, polyetherester polyols, and polyether polyols, since they are the most preferred for use with the present invention. Without wishing to be bound by theory, it is also believed that the cell opening agent would also provide similar benefits to polyurethane formulations based on other suitable foam-forming polyols such as polybutadiene polyols, polycarbonate polyols, polyacrylic polyols, and hydroxy- terminated polyolefins or other similar hydroxy-terminated polymers. As a result, it will be understood, based on this disclosure, that these materials may also be used in the base formulation without departing from the spirit of the invention and foamed using standard foam forming methods.

Useful polymeric polyols may be formed by the reaction of a polyol, preferably a diol, with a polycarboxylic acid, preferably with a dicarboxylic acid. In addition, suitable polymeric polyols for use in the base formulations of the invention may also be formed by reacting already formed polymeric polyols with other components to provide various specialty functional groups to the polymeric polyols, such as acid groups, hydroxyl groups, amine groups and the like.

The polyols useful for forming the polymeric polyols used in the invention may be any suitable monomeric or polymeric, aliphatic, aromatic, mixed or ether-containing polyol. Monomeric polyols which are preferred include ethylene glycol, diethylene glycol, 1 ,2-propanediol, 1,3-propanediol, glycerin, butanediol, hexanediol, neopentyl glycol, trimethylol propane and similar monomeric polyol compounds. Preferably, the polyol used is ethylene glycol, diethylene glycol, propanediol, butanediol, homo- or copolymers of polyethylene glycol and/or polypropylene glycol, hexanediol, neopentyl glycol and similar compounds. Most preferred for the present invention are polyols derived from ethylene glycol, diethylene glycol and similar compounds. While any suitable polycarboxylic acid, or its anhydride or derivatives, may be used, the preferred polycarboxylic acids for forming, for example, polyester or polyetherester polyols, include adipic acid, citric acid, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, fumaric acid, azeleic acid, and their aromatic and non-aromatic anhydrides and derivatives, and other similar diacids and dimers having the requisite diacid functionality. Most preferred are adipic acid, phthalic acid, glutaric acid, succinic acid, azeleic acid and mixtures, blends and other combinations of these acids. Once the polymeric polyol is formed, it can then optionally be further reacted with a monofunctional or polyfunctional carboxylic acid, alcohol, or other compound to provide a desired functionality to the polymeric polyol if useful in forming a particular commercial polyurethane foam. It will be understood, based on this disclosure, that other polycarboxylic acids and polyols can be used within the scope of this invention as long as they are capable of reacting with the polyisocyanate to form a suitable polyurethane which is capable of being foamed. In addition to the above polyol-forming components, polyanhydrides can also be used, and can include any molecule that contains two or more aromatic or nonaromatic anhydride groups. Suitable aromatic polyanhydrides include trimellitic and pyromellitic acid anhydrides. Suitable nonaromatic polyanhydrides as well as other components having mixed functionalities may also be used as described in U.S. Patent No. 5,880,250.

As the above components are reacted to form a polymeric polyol, the molecular weight builds as the reaction of the end groups and/or other functional groups of the polyol(s) react with the acid groups. Molecular weight may be varied by varying the reactants, their reactive groups and by controlling the reaction time and/or conditions to terminate the reaction when a suitable molecular weight is achieved in accordance with techniques known in the art and/or to be developed in the art for forming polymeric polyols. Most polyester polyols used in the foam industry are primarily formed from diethylene glycol and adipic acid with additional functionality imparted by incorporation of small levels of glycerin, trimethylol propane or other monomeric polyols. The preferred polyester polyols fall into two primary categories, those having a lower degree of crosslinking and a typical hydroxyl value of around 50 mg KOH/g, and a more highly crosslinked version with a hydroxyl value of around 60 mg KOH/g. These polyols are known typically as "50 hydroxyl" and "60 hydroxyl" resins. The 50 hydroxyl polyesters are normally used for textile and lamination foams. The 60 hydroxyl polyesters are more generally used to form clickable foams. Although, as noted above, the polyols may be varied. Suitable polyester polyols are available from

Inolex Chemical Company, Philadelphia, Pennsylvania.

Polyether polyols are copolymerized polyols derived from reaction of ethylene oxide, propylene oxide, butylene oxide, hydrogenated furans and the like with monomeric polyols such as those mentioned above. The reaction proceeds typically off of the hydroxy site(s) on the monomeric polyols to create the polyether chain.

Polyether polyols are available in a wider variety of crosslinking densities and molecular weights than polyester polyols. Polyether polyols for use in the present invention preferably have molecular weights Mw of about 500 to about 10,000 and hydroxyl functionalities of from about 1.5 to about 6.0. Foams formed from polyether polyols are primarily used in furniture and carpet cushions, bedding and automotive applications. Polyether polyols useful for forming polyurethane foams are available, for example, from Dow, Lyondell and Shell.

Any useful polyisocyanate capable of forming a polyurethane foam may be used in the base formulation of the present invention. Useful polyisocyanates include aliphatic, cycloaliphatic, araliphatic, aromatic polyisocyanates and combinations of these compounds which have two or more isocyanate (NCO) groups per molecule as well as their derivatives. The polyisocyanates may be organic, modified organic, organic polyisocyanate-terminated prepolymers, and mixtures thereof. Exemplary polyisocyanates include substituted and unsubstituted polyisocyanates and isomeric mixtures, including tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecane diisocyanate, octamethylene diisocyanate, decamethylene diisocyanates, cyclobutane-l,3-diisocyanate, 1,2-, 1,3- and 1 ,4-cyclohexane diisocyanates, 2,4- and 2,6-methylcyclohexane diisocyanates, 4,4'- and 2,4'-dicyclohexyldiisocyanates, 1,3,5-cyclohexane triisocyanates, isocyanatomethylcyclohexane isocyanates, isocyanatoethylcyclohexane isocyanates, bis(isocyanatomethyl)-cyclohexane diisocyanates, 4,4'- and 2,4'-bis(isocyanatomethyl) dicyclohexane, isophorone diisocyanate, 2,4- and 2,6-hexahydrotoluenediisocyanate, 1,2-, 1,3-, and 1 ,4-phenylene diisocyanates, triphenyl methane-4,4', 4"-triisocyanate, naphthylene-l,5-diisocyanate, 2,4- and 2,6-toluene diisocyanate (TDI), 2,4'-, 4,4'- and 2,2-biphenyl diisocyanates, 2,2'-, 2,4'- and 4,4'-diphenylmethane diisocyanates (MDI), polyphenyl polymethylene polyisocyanates (PMDI), mixtures of MDI and PMDI, mixtures of PMDI and TDI, aromatic aliphatic isocyanates such as 1,2-, 1,3- and 1,4- xylylene diisocyanates and m-tetramethylxylyene diisocyanate (TMXDI), and modified polyisocyanates derived from the above-isocyanates and polyisocyanates.

Typically, in the foam industry, such polyisocyanates are aromatic polyisocyanates which are based on TDI or MDI or combinations of these materials and their isomers. In slabstock foams, TDI is usually the isocyanate of choice. There are two isomers of TDI. The 2,6 isomer has two isocyanate groups which are ortho to the methyl group on the toluene ring. The 2,4 isomer has an isocyanate ortho and another para to the methyl group. Processes for manufacturing TDI always make a combination of the 2,4 and 2,6 isomers while little isocyanate is formed at the meta site. As such, other isomers, 2,3 TDI, 3,4 TDI and 3,5 TDI are present in insignificant quantities. Two types of TDI are typically manufactured for foam use. TDI-80 has

80% of the 2,4 isomer, and TDI-65 has only 65% of the 2,4 isomer. In both TDI-80 and TDI-65, the remainder is the 2,6 isomer. TDI-80 is used for textile, lamination and cushioning foams, while TDI-65 typically gives a higher air permeability and is primarily only used to make clickable foams. As such, while any of the above isocyanates may be used in the base formulations of the present invention, TDI-80, and more preferably, TDI-65 and MDI, are preferred.

Water and/or other blowing agents are critical to the polyurethane base formulation. Water reacts with isocyanate groups to produce carbon dioxide which fills the cells and expands the material into a foam. As such, water functions as a reactant, and also a blowing agent. However, in addition to water, some foam formulations also include additional blowing agents which may volatilize as the reaction gives off heat to the foam. Commonly used blowing agents include various low boiling liquids such as fluorocarbons, chlorofluorocarbons, hydrofluorocarbons, hydrochlorocarbons, acetone, cyclopentane, pentane and other low boiling materials.

Catalysts are also generally incorporated into the polyurethane base formulation in order to control reaction rates. Once the liquid components are mixed together, all reactions need to be controlled to proceed at the desired rates. In the foaming mixture, both polyol and water are vying to react with available polyisocyanate groups. When the isocyanate reacts with water it produces the carbon dioxide gas that fills the cells. This is the blowing reaction. When the isocyanate reacts with the hydroxyl groups from the polyol, it increases the average molecular weight of the resulting foam, leading to higher viscosity, gelation and finally polymer strength. This is the gel reaction. Since these reactions are proceeding at the same time, these rates must also be controlled relative to each other. For example, if the blowing reaction proceeds too quickly, the gas will bubble out of the foam before it is elastic enough to expand. In the extreme case, the foam will collapse on itself. Catalysts are added to the formulation to control each of these reactions. Normally tin or other metal catalysts primarily promote the gel reaction. Amine and other nitrogen- containing catalysts can promote either the gel or the blowing reaction depending on the specific chemical structure. In addition, the temperature of the system increases during the reaction, such that temperature sensitivity should also be taken into account when selecting a catalyst. Due to the complexity of most foam systems, several different catalysts may be selected and provided to the system in controlled amounts to provide the desired reaction rates from the mixing of the components through to the curing of the polymer. Selection of such catalysts and the amounts used vary depending on the foam to be formed and is within the ability of one skilled in the art of polyurethane foam formation.

Typical catalysts useful for the present invention include both nitrogen- based and metallic -based catalysts. Suitable nitrogen-based catalysts include reactive and unreactive tertiary amines, such as triethylenediamine, n-methyl morpholine, n- ethyl morpholine, diethylethanol amine, n-coco morpholine, l-methyl-4- dimethylaminoethyl piperazine, 3-methoxy-n-dimethylpropylamine, n,n-diethyl-3- diethyl aminopropylamine, dimethylbenzyl amine, bis(n,n-dimethylaminoethyl)ether and 1,4- diazabicyclo[2.2.2]octane, dimethylcyclohexylamine, dimethylethanolamine, urea and urea-containing compounds, and other nitrogen-based catalysts known or to be developed in the polyurethane art. Suitable metallic-based catalysts include organo- metallic catalysts or metal salt catalysts such as stannous octoate, dibutyltindilaurate, dimethyltindilaurate, dibutyltindialkylmercaptide, potassium octoate and other similar catalysts known or to be developed in the polyurethane art. Catalysts are generally added in an amount of from about 0 to about 30,000 ppm to the reaction mixture, preferred amounts for the present formulation are those amounts which are sufficient for increasing the reaction rates to the desired rate. While n-coco morpholine is typically associated with forming clickable foams, such that it is preferred for use herein either alone or blended with other catalysts, any suitable catalyst or combination of catalysts is acceptable for use with the present invention, and will depend largely on the desired foam characteristics and reaction formulation.

After mixing the liquid reactants together, bubbles form in the liquid as discussed above. As the reaction proceeds, bubbles grow and the molecular weight of the polyurethane increases, so that eventually, a matrix forms of polymer surrounding cavities filled with gas. The final foam is stabilized by the crosslinked polymer system structure, but while the reactants are still liquid, a surfactant is generally used to stabilize the bubbles and prevent them from coalescing. The surfactant also may play a role in forming nucleation sites that will become the bubbles. Generally, other additives are chosen for compatibility with and so as not to interfere with the surfactant's roles in stabilizing the bubbles and in nucleation. The most common surfactants used for polyurethane foams are silicone-based and organic non-silicone based surfactants. The silicone-based surfactants are generally polysiloxanes such as hydrolyzable and non-hydrolyzable polysiloxane-polyoxyalkylene block copolymers. Organic, non-silicone-based surfactants are commercially available, such as M6682A from Witco Chemical Company, Tegostab® B 8356 from Goldschmidt, C9110 from

Byk Chemie and LK221 from Air Products. Both silicone and organic, non-silicone surfactants available are typically blends of several subcomponents that have various emulsification and cell stabilization functions. Silicone surfactants tend to provide a better cell structure and broader processing latitude, but are not always appropriate for flame retardant formulations. Whereas, organic non-silicone types tend to provide better clickability, but generally lead to a more closed cell structure.

In typical foam formulations, different silicone and non-silicone surfactant mixtures can be distinguished by the cell size, cell uniformity and air flow characteristics they produce as well as their specific compatibility with the particular ingredients in a given formulation. While it is theoretically possible to vary air flow in such formulations simply by choosing appropriate surfactants, such adjustments are not undertaken since typically attempts to change surfactants in standard formulations will also require adjustments to the types of catalysts, catalyst concentration and other foam formulation and machine variables in view of the sensitivity of the formulations to changes in such materials and the sensitivity of the various ingredients to each other with respect to compatibility. It is therefore, considerably easier and more efficient to use a cell opening agent in accordance with the formulations of the present invention, since air flow and other properties may be modified without requiring such complex formulation changes.

Other additives include any suitable polyurethane foam additive for providing various special properties, colors, and the like provided the additive does not otherwise interfere with the beneficial clickability, air permeability and/or wettability properties achieved by the foams of the present invention. Such additives may include additional fatty acids, solvents, viscosity modifiers, flame retardants, colorants, crosslinkers, antimicrobials, fillers, light stabilizers, UV absorbers, antioxidants, release agents, plasticizers, and others. Also, paraffin oil may be further provided as an additional clickability additive to foams formed using the present invention. Paraffin oil is occasionally used as a clickability additive in polyurethane foams, but is generally not compatible with organic, non-silicone surfactants. The rising foam has a very low tolerance for paraffin oil, so that most formulations are extremely sensitive to the amount of paraffin oil provided. Too much leads to pinholing (random large cells in a fine celled foam), defoaming and collapse, while too little will not provide significant improvement in clickability. The present invention, however, provides improved effectiveness as a clickability additive in comparison with the use of paraffin oil alone, particularly with respect to the ability to use the cell opening agents of the present invention with various surfactants.

In addition to the above-identified components for use in the polyurethane base formulation, the present invention includes a cell opening agent.

The cell opening agent is a monoester or a polyester of a polyether monol or polyether polyol, preferably a mono- or diester of a polyether monol or a polyether polyol. The polyether monol or polyether polyol in the cell opening agent structure has a molecular weight Mw of from about 100 to about 2000. The cell opening agent structure preferably has a Mw molecular weight of from about 200 to about 2500, and more preferably from about 400 to about 800. The cell opening agent preferably includes at least one monofunctional or polyfunctional initiator that has at least one etherification site, and which may function as as central point for the polyether chain(s) of the polymer if multiple polyether chains are present in the cell opening agent. The initiator represents the residual portion of the initiating monomer reacted with ethylene oxide, propylene oxide, butylene oxide, hydrogenated furan and the like to form the polyether chain(s). Such initiator etherification sites have at least one of any suitable moiety representing an etherification site resulting from the etherification polymer- forming reaction, and preferably from about 1 to about 4 such sites. The sites are preferably sites derived from functional groups such as hydroxyl, amine, carboxylic acid, and carboxylic acid anhydride, however, other similar moieties representing etherification sites resulting from initiation of an etherification reaction may be provided as well. Preferably, the majority, i.e., at least 50% of the etherification sites are hydroxyl derived sites.

Suitable cell opening agents are provided by materials having the following formula (I):

P-((CH₂CHR¹-O)_nX)_m (I)

In formula (I), the (CH2CHR O)_n group represents the repeating polyether group. At the locations where the O-X linkage occurs, ester groups are introduced into the

2 backbone. X may be hydrogen or a C(O)R group, and may vary throughout the

2 polymer such that X may be independently selected as hydrogen or C(O)R within the same polymer chain. When X is hydrogen, a hydroxyl group forms with the last

2 2 oxygen from the repeating polyether unit. When X is C(O)R , a CO(O)R group forms with the last oxygen in the repeating unit, providing an ester group. Preferably, there is

2 at least one X which is a C(O)R group to provide at least one ester group to the chain.

In formula 1, m represents the number of polyether chains and is typically determined by the number of functional etherification sites or moieties on the initiating monomer. As a result, the initiator group P will be attached to one or more of such polyether polymer chains. Depending on the number of such chains, there may be several different

X groups present in the overall polymer. Preferably, the majority, or at least 50% of

2 the X groups in formula (I) are -C(O)R groups such that the measured hydroxyl

2 number of the cell opening agent is preferably less than about 100. R , when X is 2 C(O)R , may also vary along the chain and is independently selected from saturated or unsaturated, linear or branched hydrocarbon groups, preferably ranging from about 3 to about 25 carbon atoms, and more preferably from about 7 to about 19 carbon atoms.

2 When X is C(O)R and forms an ester moiety within the polymer chain, preferably the ester formed is an ester derived from a material such as lauric acid, oleic acid, stearic acid, palmitic acid, linoleic acid, myristic acid, capric acid, capryllic acid, isostearic acid or similar material and combinations thereof. However, it should be understood, that the ester is not limited to esters derived from these acids, and may include any

2 2 combination of CO(O)R with R defined as above.

R within the polyether repeating unit may also vary along the chain and may be hydrogen or a lower carbon number aliphatic hydrocarbon group such as a hydrocarbon group of preferably from about 1 to about 4 carbons. R may be saturated or unsaturated, linear or branched, lower alkyl, alkenyl, or alkynyl groups. While such groups may be substituted, they are preferably unsubstituted. Preferably, the majority, or at least 50% of R in the chain according to formula (I) above is hydrogen or methyl, with the remainder of the R moieties being one or more of ethyl, propyl, butyl and isomers thereof. It is even more preferred that the majority of R groups are hydrogen such that (CH2CHR )_n in formula (I) forms a polyethylene glycol having a molecular weight Mw of from about 100 to about 2000 and more preferably from about 200 to about 1000. In formula (I), for forming a polymer having the above noted molecular weight ranges, n preferably ranges from about 1 to about 50, and more preferably from about 1 to about 40. It is further preferred that n is from about 1 to about 25, and most preferred that n is from 2 to about 10.

P represents the initiator moiety. P is preferably any suitable monofunctional or polyfunctional moiety which has at least one etherification site remaining from the etherification reaction, and more preferably from about 1 to about 4 such sites. However, more sites are possible. In formula (I), accordingly, m typically varies from about 1 to about 10, and more preferably from about 1 to about 4. P results from the reaction of an ether-forming monomer such as ethylene oxide, propylene oxide, butylene oxide, hydrogenated furans and the like with various initiating monomers such as water, ethylene glycol, propylene glycol, glycerine, trimethylol propane, trimethylol ethane, sucrose, pentaerythritol, some amines and other similar compounds depending on the desired functionality and desired number of polyether chains. P includes the residual portion of the initiating monomers and is preferably an inorganic or organic group which includes one or more etherification sites and has one or more functional groups which may be chosen from at least one of the following exemplary functional groups singly or in combination: amine, hydroxyl, carboxylic acid, and carboxylic acid anhydride. When P has from about 1 to about 4 etherification sites, m varies accordingly from about 1 to about 4. When there are multiple etherification sites, they need not be identical, and preferably, at least half of such sites are derived from hydroxyl groups. When P has about 2 etherification sites m is about

2 2 and the majority of X groups, preferably at least 50%, are preferably C(O)R with the remainder of X groups being residual hydroxyl groups to provide a preferred hydroxyl number of less than about 100 to the resulting polymer according to formula (I).

Whether the cell opening agent includes a monoester or polyester of a polyether monol or of a polyether polyol is determined by the monomers used for etherification. The most preferred compounds useful as cell opening agents in accordance with formula (I) above, include, but are not limited to, for example, hexaethylene glycol dicaprate; polyethylene glycol dilaurate, polyethylene glycol dicocoate, polyethylene glycol dicaprylate/caprate, and polyethylene glycol dioleate, particularly polyethylene glycol-based materials in which the polyethylene glycol chain has a molecular weight of about 200, 300, 400 or 600; polypropylene glycol 425 dilaurate, polypropylene glycol 425 dicocoate, polypropylene glycol 425 dicaprylate/caprate, polypropylene glycol 425 dioleate; commercially available mixtures of these polymers and similar compounds.

In forming the base formulation for forming the polyurethane, preferably the components are present in amounts, based on 100 parts by weight of the base polyol (pph) as follows. The catalysts should be used in amounts as suggested above, and preferably from about 0.01 to about 5 pph, more preferably from about 0.1 to about 3 pph of the formulation, depending on the catalyst(s) chosen. The surfactants should be present in effective amounts depending upon the surfactant selected, and avoiding detrimental effects on bubble stabilization and nucleation, preferably in an amount of from about 0.01 to about 5 pph, and more preferably from about 0.1 to about 3 pph. Water should be used in amounts sufficient to create enough carbon dioxide to adequately fill the cells, and depending upon whether additional blowing agents are added, in an amount of from about 1 to about 10 pph, more preferably from about 2 to about 5 pph. The polyisocyanate should be provided in an amount of from about 20 to about 70 pph. Further the ratio of isocyanate groups to total hydroxyl groups in the water, polyol and cell opening additive should range from 1 :0.9 to about 1:1.25, and preferably approach 1:1 (100% index). The amount of polyisocyanate will vary, but preferably should be about 30 to about 75 pph, more preferably from about 40 to about 60 pph in the polyurethane formulation.

The cell opening agent of the present invention should be provided to the formulation in an amount effective to provide an improvement in clickability, air permeability and/or wettability to the foam without otherwise having a significant detrimental affect on other mechanical properties of the resulting polyurethane foam. Preferably, the cell opening agent is provided in an amount of from about 0.1 to 20 pph, more preferably from about 0.2 to 10 pph, and most preferably from about 0.3 to 5 pph based on 100 parts of the base polyol.

Other known additives or those to be developed, which are used for providing variation to the types of polyurethane formed as noted above, may be provided in varying quantities to achieve desired effects in accordance with techniques known or to be developed in the polyurethane foam forming art. Preferably, however, the total amount of such additives does not exceed about 50 pph, and more preferably does not exceed about 20 pph.

In addition to the polyurethane formulation described above, the invention includes a method for forming a polyurethane foam which includes providing a cell opening agent, preferably the cell opening agent described above to a polyurethane base formulation, and foaming the resulting polyurethane formulation. The base formulation may be any suitable base formulation for forming polyurethane foam, including those described in detail above. The base formulation is preferably formed by combining all components in a single liquid formulation. Commercial polyurethane foams are produced by combining each component and mixing in a standard polyurethane mix head. Such mix heads are known in the art. Alternatively, some ingredients may be pre-blended as desired. The exact nature of the mix head is not critical to the present invention. Normally, clickable foams are produced on a standard machine using relatively high mix head pressures to increase cell size. Such techniques may also be used with the present invention.

The foaming of polyurethanes is typically a one-shot process where all reactants are mixed with any number of the additional reactants and additives mentioned above with respect to the polyurethanes and the blend quickly generates foam and begins to cure. The water and/or other blowing agents can be added as a separate stream(s) to the reaction or combined ahead of time and provided simultaneously. In foaming, flexible foams may be made by any suitable foaming process including spraying, pouring, injecting, molding, and any other similar foaming process. Typical processing conditions include temperatures of from about 10 to about 50 °C and pressure of from about 0.5 to about 2.0 atmospheres, although the vast majority of pressures and temperatures are close to ambient conditions. The invention also includes a method for improving the clickability, air permeability or wettability of a polyurethane foam. The method includes forming a base formulation for forming a polyurethane foam. Any suitable polyurethane foam base formulation, particularly those described above may be used. A cell opening agent, such as the cell opening agent described above is added to the formulation, either simultaneously with the other components or sequentially, and the resulting formulation may be foamed using any of the techniques noted above. As a result of using the cell opening agent described herein, the base formulation will provide a foam which demonstrates improvement in at least one of the following properties: clickability, wettability and/or air permeability in comparison to a foam formed without the cell opening agent provided.

The invention will now be described in accordance with the following non-limiting examples:

EXAMPLE 1 Several polyurethane foam samples were made from a formulation containing 100 parts by weight of a polyester polyol, and the following components listed in parts by weight per 100 parts by weight of the polyester polyol (pph) as set forth in summary in Table 1 below: 1.0 pph nitrogen-based catalyst (urea), 0.1 pph organic (non-silicone) surfactant, 4.0 pph deionized water and 47.4 pph toluene diisocyanate, 80% 2,4 isomer (TDI-80). The TDI is provided such that the stoichiometric ratio of isocyanate groups to the sum of the amount of hydroxyl groups from the polyol, the additive, and the reactive equivalents from water is approximately 1 : 1 (i.e., at 100 index). Formulations having excess TDI-80 have an index greater than 100, while those having a deficiency of TDI-80 have an index less than 100. Several different additives as set forth in Table 2 below were added to the formulation using varied amounts and foamed using a typical hand mix (laboratory scale) foaming technique. This involved accurately weighing all components and mixing for less than about 10 seconds. The mixture was poured into a box and the foam was allowed to rise. All handling took place at ambient temperature and pressure. The resulting foams were and evaluated for their effects on air permeability, wettability and clickability.

TABLE 1

*Inolex Chemical Company **Malinckrodt

TABLE 2

* Inolex Chemical Company

** Solutia

***Dow Chemical Company Air Permeability:

Air permeability was determined using the "air hold" test. This test measures the ratio of open and closed cell windows in a particular piece of foam. Air flows through open cell windows while air flow is blocked by closed cells. A flexible polyurethane foam should have enough open cell windows that essentially all cells are open to the atmosphere through an interconnecting network of open cells. This allows the pressure in each cell to equilibrate with the atmosphere. The foam will shrink if it has too many closed cells, because the pressure of the gas inside the bubbles will decrease upon cooling, thereby creating a partial vacuum within the cells. Even foams which do not shrink can feel undesirably pneumatic if there are not enough open cell windows. There are different ways to measure air permeability of foams, and the results achieved in the Examples herein were measured by an air hold test that registers lower numbers for foams with higher air permeability. This test uses a vacuum hose attached to a 950 g aluminum fixture with a two centimeter diameter cavity. The vacuum supply line is connected to gauges which measure pressure and flow. When the fixture is held in air, the in-line vacuum is zero (atmospheric), and the flow meter records the air flow in 1/min. In this Example, the air flow was set at 8 1/min. The fixture is then set on the foam. A higher vacuum held (air hold value) indicates a higher ratio of closed to open cell windows. The test is run at 10 locations evenly spaced on a piece of foam and the values are averaged. The particular vacuum gauge used pegs the needle at 15 in. of vacuum, such that readings which were off of the scale are reflected as ">15 in" and generally indicate a high number of closed cells.

Wettability:

Wettability of the foam is measured by the "drop test." Approximately 1 ml of water is placed on the surface of the foam. The drop test value is the amount of time it takes for the water to completely pass into the foam. If the water has not completely broken the surface after one hour, the value is recorded as ">60."

Clickability:

The third test measured the ability of the foam to form a clean die cut. In this test, a slab of foam approximately 1 in. thick was cut horizontally from the block, and placed between a knife-edged die and a cutting board. The assembly was placed in a hand press and compressed to cut the foam. After removal, the foam was graded by observing the appearance of the cut edges, with the terms defined as follows:

"Excellent" -clean cut with no pinching observed on any edge immediately after cutting. "Good" - only slight pinching observed immediately after cut which may become almost clean after about 10 min.

"Fair" - moderate permanent pinching.

"Poor" - most edges completely pinched.

Some of the additives were too aggressive and caused serious defects when only 0.2 pph of the additive was used. In most of these cases, the above tests could not be completed for the resulting foams. These additives, and the results which could be achieved are listed below in Table 3 below.

TABLE 3

The remaining additives were used at varying and typically higher levels to establish whether they would effectively increase air permeability and yield a clickable foam without causing serious defects. The results for these additives and the amounts used are shown in Table 4 below. TABLE 4

Of the additives tested, the only two which showed a measurable decrease in air hold were propylene carbonate (Additive No. 8), and polyethylene glycol-400 dilaurate (Additive No. 3). Further, the polyethylene glycol-400 dilaurate showed an increase in wettability and significant improvement in clickability, indicating that the benefits of this additive exceed mere cell opening. One other diester of a polyether polyol was tested (Additive No. 6), but it was added at 1 pph or less in this test. At this level, polyethylene glycol-400 dilaurate appeared to show little effect on clickability and a slight improvement in air hold and wettability. As such, the full benefit of tetraethylene glycol di(octanoate/decanoate) is unlikely observed at the low amount tested. However, it is likely that 1 pph was not a sufficient amount of this particular additive to show benefit in the particular polyurethane base formulation used. Based on other similar tests conducted on this material, using an alternative base formulation, significant benefits were achieved with 1 pph or less of this particular cell opening agent. Propylene carbonate demonstrates properties which show use as a cell opener, but a second trial did not repeat the result shown above, and there was no significant improvement in wettability or clickability.

Many of the additives reduced foam stability as expected, which often led to defects such as splits, coarse cells and collapsed foam. Paraffin oil (Additive No. 12), the oligomeric hydrocarbon with emulsifiers (Additive No. 4), and the 800 Mw capped polyester (Additive No. 1) did show improvement in clickability, but these showed other defects in the foam, and further they had no effect on air flow or wettability. None of the other additives showed cell opening characteristics or improvement in clickability or wettability. Many of the additives, such as motor oil (Additives Nos. 14 and 15), olive oil (Additive No. 12), solvent borne polyether defoamer (Additive No. 5), 2500 Mw polypropylene glycol triol (Additive No. 10), and polymeric organic cell opening additive (Additive No. 11) were too aggressive and caused the foam to collapse when added in amounts of only 0.2 pph as shown above in Table 3. Other additives such as butyl benzyl phthalate (Additive No. 7), acetone

(Additive No. 9), propylene glycol ethers (Additives Nos 17-19), 1-octanol (Additive No. 16), and 800 Mw uncapped polyester (Additive No. 2) showed little effect on air hold, wettability, or clickability, and some also caused defects in the foam.

In conclusion, of the additives evaluated, the only additive which had the desired effects of improving all of permeability, wettability and clickability was the polyetherester, polyethylene glycol-400 dilaurate.

EXAMPLE 2 A comparison was conducted between polyethylene glycol-400 dilaurate and paraffin oil in a formulation that also included a silicone surfactant and amine catalysts. A control formulation having no cell opening additive was also foamed. The underlying foam formulation is shown in Table 5 with amounts listed in parts by weight per 100 parts polyester polyol.

TABLE 5

*Inolex Chemical Company ** Goldschmidt

The results of the evaluation of the formulations using these additives is shown below in Table 6.

TABLE 6

As demonstrated in the results in Table 6, polyethylene glycol-400 dilaurate significantly out-performed paraffin oil, which has been used in the industry as a cell opener and a clickability additive. The polyethylene glycol-400 dilaurate not only provided the benefits of clickability, cell opening and wettability, but it also produced a uniform block of foam without defects such as shrinkage and voids. EXAMPLE 3 Experiments were conducted comparing the performance of M6682A of Witco Chemical Co. with polyethylene glycol-400 dilaurate. The two additives were used in a standard formulation as set forth in Table 7 below. The results of the evaluation appear below in Table 8.

TABLE 7

TABLE 8

The polyethylene glycol-400 dilaurate demonstrated increased air flow, wettability and clickability with respect to the M6682A additive. Further, polyethylene glycol-400 dilaurate exhibited no damage in the foam appearance. EXAMPLE 4 Tests were conducted to demonstrate the effects on clickability, wettability and or air permeability derived from varying the polyether polyols as foam additives. The base foam formulation used to evaluate the various cell opening agents is set forth in Table 9 below. In all of these cases, the polyether polyols were provided with varying ester components such that O-X in formula (I) above was a combination of hydroxyl and ester groups, but primarily ester groups, and m was 2 such that P was a difunctional initiator. The varying ester groups and the average length of n from formula (I) are listed below in Table 10. The polyether components also varied such that some of the additives included an R which was hydrogen (providing a polyethylene glycol) and others included an R which was a methyl group (providing a polypropylene glycol). The test results also appear in Table 10.

TABLE 9

*Inolex Chemical Company **Goldschmidt ***Huntsman **** Air Products

The tests were conducted in the manner described above, but using an air flow rate for the air hold test of 6 1/m. Three control samples were also foamed and included formulations which omitted the use of an additive. Each of the control samples provided the same results such that only one representative control sample appears in Table 10. A comparative foam was also formed using Witco Chemical Company M6682A as an additive.

TABLE 10

Foams in the above table including "not tested," were not tested due to foam collapse. Based on the above data, while some compounds perform better than others overall, there is fairly consistent improvement in clickability in samples even when air permeability is not positively affected. The general trend is that the air flow, clickability and wet out also improve as more additive is used. The length of the fatty acid chain and number of ether units each affect the performance, as well as the amount of the additive, such that the mono- or polyester of a polyether mono- or polyol can be selected to provide a desired level of clickability. There is also some sensitivity with respect to air permeability and wettability with respect to changes in the fatty acid chain and number of ether units.

There are three primary benefits derived from the present invention: improved clickability, reduced air hold and improved wettability. However, not all benefits are universally desired in all grades of foam. For example, a manufacturer may want excellent clickability in a foam with high air flow and poor wettability. In another type of clickable foam, perhaps good wettability and low air hold may be desired. In the above Example, the length and type of the ether chain as well as the size of the fatty acid ester and the relative amount of ester and hydroxyl groups were varied. By changing the molecular nature of the cell opening agent, some foams demonstrated significantly improved clickability without increasing wettability. Others showed improvement in both of these properties together. There was also indication that clickability may be varied without significant reduction in air hold. Therefore, by changing the molecular nature of the cell opening agent, clickable foams can be produced to meet specific needs of a given polyurethane foam manufacturer without the need to vary the base formulations or surfactant/catalyst combination.

While this invention has been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations of this invention may be devised by others skilled in the art without departing from the true spirit and scope of the invention. The appended claims are intended to be construed to include all such embodiments and equivalent variations.

Claims

CLAIMS We claim:

1. A polyurethane foam formulation, comprising a cell opening agent which is a monoester or a polyester of a polyether monol or polyol, wherein the polyether monol or polyol has a molecular weight Mw of from about 100 to about 2000 and wherein the cell opening agent comprises a monofunctional or polyfunctional initiator having at least one etherification site.

2. The polyurethane foam formulation according to claim 1 , wherein the cell opening agent has a molecular weight of from about 200 to about 2500.

3. The polyurethane foam formulation according to claim 1, wherein the cell opening agent has formula I:

P-((CH₂CHR¹-O)_nX)_m (I)

wherein P is the monofunctional or polyfunctional initiator having at least one etherification site;

X is independently selected from the group consisting of hydrogen and

-C(O)R², wherein at least one X is -C(O)R²; m is from about 1 to about 10; and n is from about 1 to about 50.

4. The polyurethane foam formulation according to claim 3,

2 wherein at least 50% of X groups in the formula (I) are -C(O)R groups, and the measured hydroxyl number of the cell opening agent is less than about 100.

5. The polyurethane form formulation according to claim 3, 2 wherein R is selected from the group consisting of saturated and unsaturated linear hydrocarbons of from about 7 to about 19 carbon atoms, and saturated and unsaturated branched hydrocarbons of from about 7 to about 19 carbon atoms.

6. The polyurethane foam formulation according to claim 3, wherein at least 50% of R in the formula (I) is selected from the group consisting of hydrogen, and methyl, and less than 50% of R is selected from the group consisting of ethyl, propyl, butyl, and isomers thereof.

7. The polyurethane foam formulation according to claim 3, wherein at least 50% of R in the formula (I) is hydrogen such that (CH₂CHR )_n in formula (I) comprises a polyethylene glycol having a molecular weight Mw of from about 200 and about 1000.

8. The polyurethane foam formulation according to claim 3, wherein n is from about 1 to about 25.

9. The polyurethane foam formulation according to claim 8, wherein n is from about 2 to about 10.

10. The polyurethane foam formulation according to claim 3, wherein P has from about 1 to about 4 sites for etherification, and m is from about 1 to about 4.

11. The polyurethane foam formulation according to claim 3, wherein the at least one etherification site on P is derived from a functional group selected from the group consisting of hydroxyl, amine, carboxylic acid, and carboxylic acid anhydride.

12. The polyurethane foam formulation according to claim 11, wherein at least 50% of the etherification sites on P are derived from hydroxyl.

13. The polyurethane foam formulation according to claim 3, wherein P has about 2 etherification sites, m is about 2 and at least 50% of X is

2 -C(O)R %\ :th the remainder of X being hydrogen, and a hydroxyl number of formula

(I) being less than about 50.

14. The polyurethane foam formulation according to claim 3,

2 2 wherein when the -O-X- moiety is an -O-C(O)R group, the -O-C(O)R group is an ester derived from a material selected from the group consisting of lauric acid, oleic acid, stearic acid, palmitic acid, linoleic acid, myristic acid, capric acid, capryllic acid, isostearic acid, and combinations thereof.

15. A method for forming a polyurethane foam, comprising providing a cell opening agent to a base formulation to form a polyurethane foam formulation, and foaming the polyurethane foam formulation, wherein the cell opening agent is a monoester or a polyester of a polyether monol or a polyether polyol, wherein the polyether monol or polyether polyol has a molecular weight Mw of from about 100 to about 2000, and wherein the cell opening agent comprises a monofunctional or polyfunctional initiator having at least one etherification site.

16. The method to claim 15, wherein the cell opening agent has formula I:

P-((CH₂CHR¹-O)_nX)_m (I)

wherein P is the monofunctional or polyfunctional initiator site having at least one etherification site;

X is independently selected from the group consisting of hydrogen and -C(O)R²; m is from about 1 to about 10; and n is from about 1 to about 50.

17. The method according to claim 16, wherein n is from about 1 to about 25.

18. A method for improving clickability, air permeability or wettability of a polyurethane foam, comprising forming a base formulation for forming a polyurethane foam; adding to the base formulation a cell opening agent which is a monoester or a polyester of a polyether monol or a polyether polyl, wherein the polyether monol or polyether polyol has a molecular weight Mw of from about 100 to about 2000, and which comprises a monofunctional or polyfunctional initiator having at least one etherification site; and foaming the formulation comprising the cell opening agent to form a polyurethane foam.

19. The method according to claim 18, wherein the molecular weight Mw of the cell opening agent is from about 200 to about 2500.

20. A polyurethane foam formulation comprising: a base formulation for forming a polyurethane foam; and a cell opening agent which is a monoester or a polyester of a polyether monol or a polyether polyol, wherein the polyether monol or polyether polyol has a molecular weight Mw of from about 100 to about 2000, and wherein the cell opening agent comprises a monofunctional or polyfunctional initiator having at least one etherification site.

21. The polyurethane foam formulation according to claim 20, wherein the base formulation for forming the polyurethane foam comprises a base polyol, a polyisocyanate, a blowing agent, and at least one catalyst.

22. The polyurethane foam formulation according to claim 21 , wherein the base formulation further comprises a surfactant selected from the group consisting of silicone surfactants, and silicone-free organic surfactants.

23. The polyurethane foam formulation according to claim 21, further comprising components selected from the group consisting of flame retardants, colorants, crosslinkers, antimicrobials, fillers, light stabilizers, UV absorbers, and antioxidants.

24. The polyurethane foam formulation according to claim 21 , wherein the base polyol is selected from the group consisting polyether polyols having a molecular weight of from about 500 to about 10,000, and polyester polyols having a molecular weight of from about 1000 to about 6000.

25. The polyurethane foam formulation according to claim 21, wherein the polyisocyanate is selected from the group consisting of toluene diisocyanate, methylene diphenyl diisocyanate, and isomers and combinations thereof.

26. The polyurethane foam formulation according to claim 21 , wherein the blowing agent is water.

27. The polyurethane foam formulation according to claim 21 , wherein the at least one catalyst is selected from the group consisting of nitrogen-based catalysts, and metallic-based catalysts.

28. The polyurethane foam formulation according to claim 21 , wherein the formulation comprises the cell opening agent in an amount of from about

0.1 to 20 parts by weight per 100 parts by weight of the base polyol.

29. The polyurethane foam formulation according to claim 28, wherein the formulation comprises the cell opening agent in an amount of from about 0.2 to 10 parts by weight per 100 parts by weight of the base polyol.

30. The polyurethane foam formulation according to claim 29, wherein the foam formulation comprises the cell opening agent in an amount of from about 0.3 to 5 parts by weight per 100 parts by weight of the base polyol.