WO2020068508A1

WO2020068508A1 - Rebonded polyurethane foam

Info

Publication number: WO2020068508A1
Application number: PCT/US2019/051684
Authority: WO
Inventors: Thomas H. Peter; Priyesha BISWAS; Bruno Cesar Silva MOTTA
Original assignee: Lanxess Solutions Us Inc.
Priority date: 2018-09-25
Filing date: 2019-09-18
Publication date: 2020-04-02

Abstract

Elastomeric composites, such as composites comprising polymeric foam particles and a binder, are prepared by curing a mixture of foam particles and a moisture-curable binder composition, which binder comprises an isocyanate capped prepolymer and from 20 to 70 wt%, based on the weight of the binder composition of a natural oil or modified natural oil plasticizer.

Description

REBONDED POLYURETHANE FOAM

A composition and process for preparing elastomeric composites, such as composites comprising polymeric foam particles and a binder, are provided, the composition comprising a binder composition comprising an isocyanate capped prepolymer and from 20 to 70 wt%, based on the weight of the binder composition of a natural oil or modified natural oil plasticizer.

Elastomeric composites prepared by mixing polymeric particles, e.g., rubber crumb, shredded polyurethane foam, and the like, with a binder material and then curing the binder material are known. Polyurethanes are commonly used as the binder material, because of their elastomeric properties, curing characteristics and ability to bond well to elastomers such as rubber and polyurethane. Polyurethane binders can be two-component or one- component types. Many, especially, one-component polyurethane binders, contain an isocyanate-terminated prepolymer. In such processes, curing is typically achieved through a reaction of the terminal isocyanate groups with water, but reaction with crosslinkers such as polyols is known. One-component systems are easy to use and do not require metering or mixing steps in the field in order to produce a curable binder composition, and in certain cases, can be conveniently cured using atmospheric moisture.

U.S. Pat. No. 5,185,380 discloses conversion of scrap polyurethane foam to small pieces which are then consolidated under heat and pressure and pressed to form a sheet. Methods for reuse of scrap polyurethane foam involve converting it into small pieces, coating the pieces with a binder and then placing them in a mold under conditions to cause the binder to cure, e.g., steam is often used in curing the binder. Various binders have been employed, e.g., polyester/epoxy mixture, polyurethane foam prepolymer, polyurethane resin and MDI and/or urethane polymer. These products are sometimes called rebonded foams.

CA 2,179,145 discloses a method for preparing a highway impact barrier of rebonded rubber particles by curing a composition comprising a polyurethane prepolymer, a diol or polyol curing agent and rubber particles US 2006/0094794 discloses blending polyurethane foam particles with moisture resistant polyurethane prepolymers, and then curing the composition with steam to form a rebonded foam. US 8,501 ,828 discloses blending polyurethane foam particles with either polyurethane prepolymers, or the polyol and isocyanate reactants used to prepare prepolymers, and then curing the composition with steam to form a rebonded foam When using an isocyanate-terminated prepolymer in a binder, the viscosity of the prepolymer is an important consideration. If the viscosity is too high, it is difficult to mix the prepolymer uniformly with the elastomeric particles, which can cause inconsistencies in the product due to polyurethane-rich regions and polyurethane-poor regions where the rubber or polymer foam particles may not be adequately bound. If the viscosity is too low, the prepolymer can run off of the particles, which can also cause inadequate bonding between particles.

Prepolymer viscosity is affected by factors such as the equivalent weights and functionality of the polyols and isocyanates, the isocyanate content of the prepolymer, and the like.

Although these parameters may be manipulated to adjust the viscosity of a prepolymer, there are limits to what can be accomplished in this way as these parameters also affect the curing characteristics of the prepolymer and the physical properties of the resulting polyurethane binder. Therefore, the amount to which the prepolymer equivalent weight, crosslink density and/or isocyanate functionality can be manipulated in order to produce a desirable viscosity is constrained by the needed curing and physical property characteristics.

The more common approach to viscosity control is through the presence of a diluent, e.g., process oil, plasticizer, etc. Dioctyl phthalate is a commonly used diluent/plasticizer in these applications but it is under regulatory pressures. Diisononyl phthalate is a similar plasticizer, and possible substitute, but it is more expensive than dioctyl phthalate. In addition to lowering viscosity, the diluent must form a binder composition that is storage-stable, and some diluents have been known to separate out upon standing. Further, the prepolymer must still cure reasonably rapidly to form a binder that adheres well to the rubber particles, without interference from the diluent.

Methods are known that bind rubber crumb and plastic particles with polyurethane without using a prepolymer. US 5,610,207 discloses coating a portion of polyurethane foam particles with a polyol, another portion with a polyisocyanate and then consolidating the portions to cause the binder to cure. In the process of WO 02/077083, a polyisocyanate is mixed with a polyol just before the combination is mixed with flexible foam crumbs, and the resulting mixture is then placed in a mold and heated to complete cure.

Methods for forming rebonded foam using polyurethane prepolymers in a binder composition continue to be developed. US 7,566,406 discloses a process for forming rebonded foam using a polyurethane prepolymer formed from an isocyanate and a vegetable oil polyol, wherein the pre-polymer is substantially free of petrochemical polyol. The prepolymer, typically in the presence of a process oil added to modify the viscosity of the pre-polymer is used to coat foam pieces, which are then compressed into a foam log and subjected to steam to cure the pre-polymer.

US 8,962,771 discloses a process for forming rebonded materials wherein particles of a natural or synthetic rubber are wetted with a liquid one-component moisture-curable resin composition and then exposing the wetted particles to moisture to cure the resin

composition. No steam is needed. The moisture-curable resin composition comprises (a) an isocyanate-terminated polyurethane prepolymer and (b) from 1 to 30%, based on the combined weight of components (a) and (b), of an epoxide or lactone compound having a molecular weight of from about 70 to about 1000. As component (b), glycidyl ethers at 3 or 5 % are shown to have no negative impact on cure time.

More work needs to be done to broaden the range of effective methods and acceptable binders for producing these elastomeric composite materials, such as those prepared from polyurethane foams. For example, binder compositions that remain stable, without separation, at higher levels of plasticizer and cure in an acceptable time to provide an acceptable elastomeric composition, which compositions also avoid complications seen with plasticizers such as di-octyl phthalate such as exudation and environmental concerns. Binders that allow for lower treatment rates vs the foam crumb, and still provide good bonding are also highly desirable.

SUMMARY OF THE INVENTION

The invention provides a process for preparing an elastomeric composite, e.g., rebonded polyurethane foam, the process comprising wetting particles of a preformed polymer foam with a moisture-curable binder composition to form an uncured composite composition, exposing the uncured composite composition to moisture under conditions wherein the binder composition cures, forming a binder phase that adheres the particles together, to produce the elastomeric composite.

Introducing moisture, or exposing the uncured composite composition to moisture, may occur in a variety of ways and at various points in the process. For example, moisture may be introduced by applying water to the preformed polymer foam before it is mixed with the moisture curable binder composition, moisture may be introduced to the moisture-curable binder composition directly or indirectly at any time, and/or the uncured composite composition can be exposed to atmospheric moisture or liquid water after the mixing of the foam particles and binder composition and any other composition components. In addition to the use of ambient atmospheric moisture, steam, or air with otherwise increased amounts of water vapor, may also be used as a form of enhanced atmospheric moisture.

One embodiment of the invention provides a process for forming a composite material, e.g., a rebonded foam, comprising

1 ) wetting elastomeric particles such as particles from a preformed polymer foam, e.g., a polyurethane foam, with a binder composition to form an uncured composite composition, the binder composition comprising:

a) from 30 to 80 wt%, e.g., from 30 to 65 wt% or from 33 to 60 wt%, based on the weight of the binder composition, of an isocyanate capped prepolymer and

b) from 20 to 70 wt%, e.g., from 35 to 70 wt% or from 40 to 67 wt% based on the weight of the binder composition, of a natural oil or modified natural oil plasticizer, wherein the uncured composite composition comprises from 65 to 99 wt%, e.g., from 75 to 95 wt% elastomeric particles such as particles from a preformed polymer foam, e.g., a polyurethane foam, based on the weight of elastomeric particles and binder;

and

2) curing the uncured composite composition by the action of water, either as atmospheric moisture or liquid water, which water may be introduced at various points in the reaction as described above.

Another embodiment of the invention provides a composition or mixture for forming an elastomeric composite, e.g., a rebonded foam, comprising:

A) from 1 to 35 wt%, e.g., from 5 to 25 wt%, of a binder composition comprising:

a) from 30 to 80 wt%, e.g., from 30 to 65 wt%, from 33 to 60 wt%, based on the weight of the binder composition, of an isocyanate capped prepolymer and

b) from 20 to 70 wt%, e.g., from 35 to 70 wt%, or from 40 to 67 wt% based on the weight of the binder, composition, of a natural oil or modified natural oil plasticizer, and

B) from 65 to 99 wt%, e.g., from 75 to 95 wt% elastomeric particles, such as particles from a polymer foam, e.g., a polyurethane foam.

In the present disclosure,“moisture-curable binder composition” is used interchangeably with“binder composition”.

A further embodiment provides an elastomeric composite comprising elastomeric particles such particles of a polymer foam, e.g., polyurethane foam particles, and a cured

polyurethane binder, prepared according to the above composition or process. In carrying out the studies for the invention, it seemed that successful compositions comprised a plasticizer that could be absorbable by the elastomeric particles, in particular the polymer foam or polyurethane foam particles. That is, in the final product, it often seems that the plasticizer resides inside the polyurethane foam crumb while little to no plasticizer is found on the surface of the foam crumb.

DESCRIPTION OF THE INVENTION

The particles used in the instant invention are typically particles of polymer foams e.g., polyurethane foams, that are bound into a coherent material by the binder. Virgin material can be used for the particles, but for cost reasons it is generally preferabe to use reclaimed material such as scrap polyurethane foam. Large pieces of foam can be shredded, cut, chopped, ground etc., using any of the methods known in the art to provide particles of the appropriate size.

The elastomeric particles generally have a longest dimension of no greater than about 50 mm or 30 mm, for example, no greater than about 20 or 15 mm, and in certain

embodiments, no greater than about 10 mm. For convenience of handling and processing, it is preferred that the elastomeric particles are at least 1 mm, and preferably at least 3 mm, in at least one dimension.

The foam particles, e.g., polyurethane foam particles, are typically the majority component in the uncured composite composition. For example, the amount, by weight, of the binder composition in the uncured binder / polyurethane foam particle compositions is from 4 to 35%, 4 to 30%, 5 to 25%, 6 to 20%, or 8 to 12%.

The prepolymer of the invention is prepared from a polyol and a polyisocyanate using any method. Typically, the prepolymer is prepared to have an isocyanate content of from 5 to 15%, e.g., 7 to 12 %.

In the present application, the term“a” or“an” means one or more than one unless otherwise indicated.

Polyols useful in the preparation of the isocyanate-terminated polyurethane prepolymer can include high MW polyols, for example, having a number average molecular weight of about 250 and to about 20,000, often from about 650 to 3000, and low MW polyols, e.g., less than 250. Combinations of high MW and low MW polyols may be used. Useful polyols generally contain from two to four hydroxyl groups per molecule, and generally two or three hydroxyl groups per molecule. Mixtures of polyols may be used, e.g., mixtures of diols and triols.

Any of the typical classes of polyols used in the polyurethane arts may be used. Many embodiments employ alkyl polyols, polyether polyols or polyester polyols, such as polyether diols and triols, e.g., polyether diols.

Examples of polyether polyols include polyalkylene ether polyols having the general formula HO(RO)nH, wherein R is an alkylene radical and n is generally an integer large enough that the polyether polyol has a number average molecular weight of at least 250. Polymers and co-polymer may be used. Such polyalkylene ether polyols are well-known and can be prepared by the polymerization of cyclic ethers such as alkylene oxides and glycols, dihydroxyethers, and the like, using methods known in the art. For example, a polymer or copolymer of a polymerizable aliphatic cyclic ether such as ethylene oxide, propylene oxide,

1 .2-butylene oxide, tetramethylene oxide and the like. A suitable copolymer, for example, is a random copolymer of propylene oxide and ethylene oxide; another suitable copolymer is a block copolymer of propylene oxide and ethylene oxide. Mixtures of polyols may be used, e.g., a mixture of polypropylene glycol diol and a polypropylene glycol triol, such as a mixture of a polypropylene glycol diol with a MW of about 1000 and a polypropylene glycol triol with a MW of about 3000.

Useful polyester polyols can be prepared, e.g., by reacting dibasic acids, e.g., adipic acid, sebacic, phthalic acid, unsaturated fatty acids, and the like, with diols such as ethylene glycol, 1 ,2-propylene glycol, 1 ,4-butylene glycol and diethylene glycol, tetramethylene ether glycol, and the like.

Low MW polyols, i.e., polyols with an average molecular weight of less than 250, are most typically used as the minor part of a High MW / Low MW polyol mixture, and include, e.g., alkyl glycols such as ethylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol,

1 .3-butanediol, 1 ,4-butanediol, trimethylol propane, low MW PEG or PPG diols and triols including ethoxylated diols and triols and the like.

The polyisocyanate used to make the prepolymer may be an aliphatic polyisocyanate or an aromatic polyisocyanate, or mixtures thereof. Typically an aromatic polyisocyanate is used such methylene diphenylisocyanate (MDI), including any of the various isomers thereof, derivatives and polymers of MDI including e.g., polymethylene polyphenylisocyanate and the like. Good results are obtained using MDI, and in many embodiments the prepolymer is prepared from a polyether polyol, often a diol and/or triol, and MDI. One advantage MDI has over other isocyanates is that MDI prepolymers readily cure with moisture but isocyanates such as TDI are slower to cure with moisture. Further, MDI has a lower vapor pressure and presents less of a vapor hazard.

Natural oil plasticizers include soybean oil, canola oil, linseed oil, tung oil, coconut, palm, olive oil, cotton seed oil, sunflower oil, and the like, alkyl esters of natural oil fatty acids, such as octyl tallate, and modifications of these, such as acylated, oxidized or epoxidized natural oils, for example, epoxidized soybean oil.

Epoxidized natural oils are of particular interest because their compatibility with the urethane binder and foam systems is improved relative to unmodified natural oils, while they also remain inherently economical vs other plasticizers such as many ester plasticizers. As opposed to the epoxides exemplified in US 8,962,771 , which are glycidyl ethers, epoxidized natural oils in the present invention refers to compounds wherein one or more epoxy groups are situated on a the fatty acids of the natural oil molecule. They are known in the art to be much less reactive than the glycidyl ethers used in US 8,962,771 and would not be expected to react in the polyurethane binder system.

Without wishing to be bound by theory, it is believed that the epoxidized oils and other oils of this invention are particularly effective in binder formulations because they provide reduced viscosity for good foam wetting, but then migrate out of the binder and into the foam matrix, leaving a binder with low plasticizer levels and good physical bonding strength. As evidence of this effect, rebonded foam samples were made with a binder that comprised equal weights of polyurethane prepolymer and plasticizer. After curing, IR measurements on the surface of the foam particles showed little to no plasticizer on the surfaces that should have been coated with binder.

In many embodiments, the natural oil or modified natural oil plasticizer is present in the binder composition at a concentration of about 20 wt % to about 70 wt%, e.g., from about 30 or 35 wt% to about 70 wt% or from about 40 or 50 wt% to about 65 wt%, based on the weight of the binder composition.

As stated above, the binder composition comprises a prepolymer, which is prepared from a polyol and polyisocyanate, and a natural oil or modified natural oil plasticizer. In various embodiments, mixtures of 2 or more prepolymers and/or 2 or more natural oil or modified natural oil plasticizers are used. There is no limitation on how the plasticizer is mixed with the prepolymer. The plasticizer can be mixed with the prepolymer after the prepolymer is prepared, or some or all of the plasticizer may be present during the reaction of polyol with polyisocyanate.

The binder composition is formulated to be liquid at 25°C and is a liquid when used to wet or coat the particles. Other ancillary materials known in the art may also be present at conventional concentrations, e.g., from 0 or 0.1 to 5, 10, or 15% wt%, such as, catalysts, fillers, dyes, pigments, compatibilizers, surfactants, etc. Such materials and their use are well known to one skilled in the art and need not be further discussed here.

Mixing the foam particles with the binder composition to form the uncured composite composition can be done in any convenient fashion that permits the surfaces of the polymer foam particles, to become adequately wetted with the prepolymer. The mixing step is generally conducted at a temperature of from about 0 to about 40°C, although any convenient temperatures may be used. Elevated temperatures are not typically needed due to the ability of the natural oil or modified natural oil plasticize to reduce viscosity.

Curing is accomplished by exposing the uncured composite composition to moisture. In one embodiment, this is conveniently accomplished by using atmospheric moisture, which comes into contact and reacts with the isocyanate groups. Ideally this occurs under ambient conditions, using whatever moisture is in the air and at whatever the temperature in the local environment happens to be, although in some embodiments heating may be employed, typically less than 80°C, e.g., 60°C or less, 50°C or less, 40°C or less or 35°C or less. In some embodiments, conventional steps may be taken to increase the relative humidity.

In another embodiment, liquid water is added to the mixture of particles and binder composition. For example, water can be mixed with the binder composition or with the elastomeric particles just before those components are themselves combined, or water can be added after the elastomeric particles have been wetted with the binder composition. Again, there is typically no need to heat the resulting mixture to cure the composition, although one may choose to do so.

The elastomeric particles wetted with the binder composition may be transferred to a mold before cure as known in the art. The mold can be of any shape or size, for example, a drum mold may be used. The addition of liquid water to a composition is more likely to be needed to promote a faster cure by a composition in a mold than a composition spread out in the open with greater surface area exposed to the atmospheric moisture. As above, the mold may be heated if desired, especially as a means to increase reaction rate and thereby productivity. In one embodiment, steam is used to simultaneously provide moisture and heat the composition to effect a speedy cure.

In many embodiments, upon completion of the cure, the cured mass is removed from the mold, and then cut or shaved to form mats of a desired thickness. The mats can be fabricated further to produce a variety of articles such as gaskets, gymnasium mats, carpet underlayment, mattresses, mattress components, or other sealing or cushioning products.

The mold may also be one with internal dimensions that match those of a final product. The mold may contain a substrate to which a resulting cushion is to be attached, as is the case in producing cushion-backed carpet tile.

In any of these curing approaches, the wetted particles may be more or less tightly compacted. Higher compaction leads to a smaller void volume, a higher density product and typically a firmer product. Less compaction can lead to greater void volume, lower product densities and a softer product. Void volume is also affected by the ratios of moisture-curable resin composition and elastomeric particles; with higher ratios (relatively more of the resin composition) typically leading to lower void volumes, as greater quantities of the liquid prepolymer causes the spaces between the particles to become more completely filled.

In many embodiments of the invention, the uncured composite composition is placed into a mold and pressed until cured; in some embodiments heat is applied to the mold during cure.

As an example, according to one embodiment of the invention, a prepolymer is made by reacting 4,4’MDI with sufficient PPG polyol under standard conditions to achieve a final NCO content of 6-20% NCO, in one embodiment about 10% NCO. The PPG polyol is typically a diol and/or triol of 250-20000 MW. Other polyols and glycols can also be added to influence the properties of the prepolymer. Once the reaction is complete and the NCO content has reached the target, 30 to 200 phr natural oil or modified natural oil plasticizer is added. Optionally, 0.1 -10.0 phr of a compatibilizer or surfactant is added to help prevent any separation on storage, and in some embodiments, a catalyst to accelerate the reaction with moisture may be added. This mixture is then mixed with foam crumb in a 0.5:10 to 2:10 by weight ratio of binder to crumb and in some embodiments a catalyst is added. Water may optionally be added to the foam crumb either before the prepolymer mixture or after, and mixed in thoroughly. The resulting uncured composite composition is then placed in a mold and pressed until cured, in some embodiments, the molded composition is heated to temperatures of up to 80°C or exposed to steam during cure.

For example, equal amounts by weight of 1000 MW diol and 3000 MW triol PPG were added to a reactor that contained sufficient MDI to reach 10% NCO. Upon completion of the reaction an equal weight of a plasticizer, i.e., 100 phr, is added, such as 100 phr of epoxidized soybean oil or 100 phr of linseed oil. From 0-10.0 phr of a compatibilizer or surfactant is added. The mixture is thoroughly mixed with foam crumb in a 1 :10 by weight ratio of binder to crumb. Catalyst is optionally added either to the crumb or the binder composition. In many embodiments, water is optionally added to the foam crumb either before the prepolymer mixture or after. After mixing thoroughly, the coated foam crumb is placed in a mold and pressed until cured.

As another example, 3000 MW triol PPG was added to a reactor containing sufficient MDI to reach 10% NCO. After a suitable period for reaction, enough polymethylene polyphenyl isocyanate is added to achieve a final NCO content of from 13 to 18 % NCO. Upon completion of the reaction, plasticizer and optional compatibilizer or surfactant is added as above. Catalyst is added either to the crumb or the binder composition. In many embodiments, water is optionally added to the foam crumb either before the prepolymer mixture or after. After mixing thoroughly, the coated foam crumb is placed in a mold and pressed, typically with applied heat or steam, until cured.

Claims

CLAIMS What is claimed is:

1 . A process for preparing an elastomeric composite, the process comprising wetting particles of a preformed polymer foam with a moisture-curable binder composition to form an uncured composite composition and exposing the uncured composite composition to conditions wherein the moisture-curable binder composition is cured to form a binder phase which adheres the particles together, wherein the moisture-curable binder composition comprises:

a) from 30 to 80 wt%, based on the weight of the binder composition of an isocyanate capped prepolymer and

b) from 20 to 70 wt%, based on the weight of the binder composition,

of a natural oil or modified natural oil plasticizer

c) from 0 to 10 wt%, based on the weight of the binder composition, ancillary materials,

wherein moisture is introduced to the uncured composite composition by exposing the preformed polymer foam, the moisture-curable binder composition, and / or the uncured composite composition to ambient atmospheric moisture, enhanced atmospheric moisture or liquid water.

2. The process according to claim 1 wherein the uncured composite composition comprises the

from 1 to 35 wt% of the moisture-curable binder composition and from 65 to 99 wt% of the polymer foam.

3. The process according to claim 1 wherein the uncured composite composition comprises the

from 5 to 25 wt% of the moisture-curable binder composition and from 75 to 95 wt% of the polymer foam.

4. The process according to claim 1 wherein the natural oil or modified natural oil plasticizer is absorbable by the polymer foam.

5. The process according to claim 1 wherein the prepolymer is prepared from MDI and a polyether polyol.

6. The process according to claim 1 wherein the moisture-curable binder composition comprises:

a) from 30 to 65 wt% of the isocyanate capped prepolymer and

b) from 35 to 70 wt% of the natural oil or modified natural oil plasticizer.

7. The process according to claim 1 wherein the moisture-curable binder composition comprises:

a) from 33 to 60 wt% of the isocyanate capped prepolymer and

b) from 40 to 67 wt% of the natural oil or modified natural oil plasticizer.

8. The process according to claim 1 wherein the ancillary materials comprise a

compatibilizer, surfactant, or catalyst.

9. The process according to claim 1 wherein the polymer foam is a polyurethane foam.

10. The process according to claim 1 wherein the natural oil or modified natural oil plasticizer comprises soybean oil, epoxidized soybean oil, canola oil, linseed oil, tung oil, coconut, palm, olive oil, cotton seed oil, sunflower oil, or octyl tallate.

1 1 . A composition for preparing an elastomeric composite, the composition comprising:

A) from 1 to 35 wt% of a binder composition comprising:

a) from 30 to 80 wt%, based on the weight of the binder composition, of an isocyanate capped prepolymer,

b) from 20 to 70 wt%, based on the weight of the binder composition, of a natural oil or modified natural oil plasticizer,

c) from 0 to 10 wt%, based on the weight of the binder composition, ancillary materials.

and

B) from 65 to 99 wt%, of preformed polymer foam.

12. The composition according to claim 1 1 , wherein the polymer foam is a polyurethane foam.

13. The composition according to claim 1 1 wherein the natural oil or modified natural oil plasticizer is absorbable by the polymer foam.

14. The composition according to claim 1 1 wherein the prepolymer is prepared from MDI and a polyether polyol.

15. The composition according to claim 1 1 wherein the binder composition comprises: a) from 30 to 65 wt% of the isocyanate capped prepolymer and

b) from 35 to 70 wt% of the natural oil or modified natural oil plasticizer.

16. The composition according to claim 1 1 wherein the binder composition comprises: a) from 33 to 50 wt% of the isocyanate capped prepolymer and

b) from 50 to 67 wt% of the natural oil or modified natural oil plasticizer.

17. The composition according to claim 1 1 wherein the ancillary materials comprise a compatibilizer, surfactant, or catalyst.

18. The composition according to claim 1 1 comprising from 5 to 25 wt% of the moisture- curable binder composition and from 75 to 95 wt% of the polymer foam.

19. A polymer composite prepared according to claim 1 .

20. A polymer composite prepared according to claim 1 1 .