CA1158817A

CA1158817A - Foam composites of polyurethane integral skin foam and non-polyurethane foam and a process for their manufacture

Info

Publication number: CA1158817A
Application number: CA000343978A
Authority: CA
Inventors: Heinrich Horacek; Dietmar Nissen; Udo Haardt; Erhardt Reich
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1979-01-20
Filing date: 1980-01-18
Publication date: 1983-12-20
Also published as: DE2902255A1

Abstract

FOAM COMPOSITES OF POLYURETHANE INTEGRAL SKIN FOAM AND
NON-POLYURETHANE FOAM AND A PROCESS FOR THEIR MANUFACTURE

Abstract of the Invention Foam composites are prepared from polyurethane integral skin foams and non-polyurethane foams such that 60 volume percent to 90 volume percent is the non-polyurethane foam. A foamable polyurethane integral skin mixture is foamed in a sealable mold with a slab of already formed non-polyurethane foam. Flexible polyurethane integral skin foams and flexible non-polyurethane foams are combined as well as rigid polyurethane integral skin foams and rigid non-polyurethane foams.

Description

~ 7 FOAM COMPOSITES OF POLYURETHANE INTEGRAL SKIN FOAM AND
NON-POLYU~ETHANE FOAM AND A PROCESS FOR THEIR MANUFACTURE
Backqround of the Invention l. Field of the Invention The invention relates to foam composites comprising a polyurethane integral skin foam and a non-polyurethane foam.

2. Description of the Prior Art The manufacture of foam combinations and foa~
composites containing a polyurethane foam component is the subject of numerous publications and patents.
Foam combinations are manufactured by foaming together expandable polyolefin particles generally incor-porated in a foamable polyurethane mixture (U.S. Patents

3,607,797 and 3,662,043) or by completely foaming, generally in molds, foamed polymer particles mixed with a foamable polyurethane mixture (German Published Application 21 28 684 and 22 62 250).
Foam composites generally have a variable number of layers of polyurethane and non-polyurethane foams. The individual layers are either glued to each other or a foamable polyurethane mixture is applied to the substrate and allowed to foam ~U.S. Patent 3,833,259 and German Published Applica-tion 23 42 292).
The mechanical properties of individual foams may be combined in a foam combination or foam composite.

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There are, however, limita.tions.to.these foams. The manufactu~ing processes i~.most cases.are expen.si.ve, the combination:of polyu-rethane to non-polyuxethane foam is un.favorable.since no more than 50 volume percent of non-polyurethane foam particles can be incor-porated in the coherent polyurethane foam matrix; furthermore, the' surfaces generally have to be additionally coated, laminated or finished..
Summary of the Invention . The object of the present invention is to develop foam composites which do not have the above-mentioned limitations and which ha~e a den.se compact skin of polyurethane with good physical properties on at least one surface. Surprisingly, the above-mentioned limitations are resolved by foam composites comprising a polyurethane integral skin foam and non-polyurethane foam.
In particular, the present invention provides, a foam com-posite comprising 40 v.olume percent to 10 volume percent, based on the total ' volume of the foam composite, of a polyurethane integral skin foam and 60 volume perce~t to 90 volume percent, based on the total volume of the foam composite, of a non-polyarethane foam, wherein the non-polyurethane foam is enclosed by a dense, compact outer skin of polyurethane integral skin foam on more than two surfaces having a degree of ccmpacting of 1 to 4 and being without a glue or binder layer between the foams.
In accordance with the present invention the non-polyurethane foam may be a six sided non-polyurethane foam enclosed by a dense, compact outer skin of`polyurethane integral skin foam, . having a degree of compacting between 1 and 4 on more than one f !
the six sides of the polyurethane foam.
. In accordance with another aspect of the present in-vention there is provided a process for the manufacture of a foam .30 composite of a polyurethane integral skin foam and a non-polyure-thane foam comprising either I. .a. feeding a foama.ble polyurethane .integral A

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skin mixture in itS flowable state into a sealab~e ~o~d in such a quantity that a degree of compacting o~ 1 to 4 is achieved upon foaming, b. adding the non-polyurethane foam to the still flowable polyurethane integral skin mixture, - c. sealing the mold, and d. allowing the polyurethane integral skin mixture to foam such that a dense, compact outer skin forms on at least one surface, or II. a. feeding a foamable polyurethane integral skin mixture onto the bottom band of a tun-nel-shaped mold, b. feeding the non-polyurethane foam onto the foamable polyurethane integral skin mixture, c. adjusting the length of the tunnel and throughput of feed materials to obtain the desired foam composite at the product end of the tunnel-shaped mold, and d. allowing the polyurethane integral skin mix-ture to foam such that a dense compact outer skin of polyurethane integral skin foam forms on at least one surface.
In accordance with the present invention the degree ~ -,.
of compacting may be 1.5 to 3.
The foam composites of this in~ention haYe the ad~an-tage that they have a tight external polyurethane skin having a high tearing and bending strength on the s~rface. Other proper~
ties such as density, compression resiliency, and burning beha~ior, are determined by the non-polyurethane foam.

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~5~7 In accordance with the present in~ention, the polyure-thane integral skin foam may, for example, be made frorn a poly-ether polyol based on propylene oxide and ethylene oxide; a poly-ether polyol based on trimethylolpropane, propylene oxide and ethylene oxide; butanediol; and ethylene glycol reacted with an isocyanate group containing prepolymer made from reacting

4,4'-diphenylmethane diisocyanate with dipropylene glycol. The polyurethane integral foam may also, for example, be made from a polyether polyol based on ethylenediamine, propylene oxide and ethylene oxide, a difunctional polyether polyol based on propy-lene oxide and ethylene oxide, trimethylolpropane and ethylene glycol reacted with an isocyanate mixture of diphenylmethane di-isocyanates and polyphenyl polyme-thylene polyisocyanates.
In accordance with the present invention, the non-polyurethane foam may, for example, be a urea formaldehyde foam or an expanded polystyrene foam.
Description of the Preferred Embodiments -The ratio of foamable polyure-thane integral skin foam mixture and non-polyurethane foam used for the manufacture of foam composites can be varied within wi.de limits. Generally, 20 parts to 500 parts, preferably 50 par-ts to 150 parts, of -the foamable polyurethane integra:L skin mixture -- 2b -1 1588:~

are used per volume of non-polyurethane foam. In this manner, foam composites are obtained which comprise 40 volume percent to 10 volume percent, preferably 30 volume percent to 15 volume percent, of a polyurethane integral skin foam and 60 volume percent to 90 volume percent, preferably 70 volume percent to 85 volume percent, of a non-polyurethane foam, the volume percent being relative to the total weight.
For the manufacture of foam composites, it is appropriate that flexible, elastic polyurethane integral skin foams are combined with flexible non-polyurethane foams and that rigid polyurethane integral skin foams are combined with rigid non-polyurethane foams. Foam composites that work well also comprise a flexible elastic polyurethane integral skin foam and a rubber latex, an elastic polystyrene foam or a polyolefin foam, and foams comprising a rigid polyurethane integral skin foam and a polystyrene foam, phenol-formaldehyde, `~
melamine-formaldehyde, urea-formaldehyde foam, polyvinyl -chloride foam, polyamide foam, polyester foam, or an inorganic foam based on silicates, expanded clay, or perlite.
Depending on the type of polyurethane integral skin foam and non-polyurethane foam, foam composites may be produced which have very specialized properties. Thus, for instance, foam composites comprising polyethylene foams and flexible, elastic polyurethane integral skin foams are particularly well suited as gymnastic pads. However, they may also be used as wall coverings for gyms. Such foam composites combine the high damper power of the polyethylene foam with .. ... . . .
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the high tensile strength and tear strength of the flexible polyurethane integral skin foams.
The flexible, elastic and rigid polyurethane integral skin foams of this invention to be used are produced from the following ingredients: polyisocyanates, polyols, blowing agents, catalysts and additives.
Typical examples of polyisocyanates include ali-phatic, cycloaliphatic, aryl, aliphatic, heterocyclic, and preferably aromatic organic polyisocyanates. Representative examples include: aliphatic diisocyanates such as ethylene, 1,4-butane, 1,6-hexane and 1,12-dodecanediisocyanate; cyclo-aliphatic diisocyanates such as 1,3- and 1,4-diisocyanatocyclo-hexane, as well as any desired mixture of these isomers, l-isocyanato, 3,3,5-trimethyl, 5,isocyanatomethyl cyclohexane, 2,4- and 2,6-diisocyanato methylcyclohexane, as well as any desired mixtures of these isomers, 4,4'- and 2,4'-diisocyan-atodicyclohexylmethane; aromatic diisocyanates such as 1,3-and l,4-phenylene diisocyanate, 2,4- and 2,6-toluene diisocy-anate as well as any desired mixtures of these isomers, 2,2'-, 2,4'- and 4,4'-diphenylmethane diisocyanate and naphthalene-l,

5-diisocyanate; aromatic polyisocyanates such as 4,4',4H-tri-phenylmethanetriisocyanates, 2,4,6-triisocyanatobenzene and polyphenylpolymethylenepolyisocyanates. Modified polyisocyan-ates may also be used. These include the polyisocyanates described in U.S. Patent 3,492,330, polyisocyanates containing carbodiimide groups (German Patent 10 92 007), polyisocyanates containing allophanate groups (British Patent 994,890; Belgian - ~ .

Patent 761,626), polyisocyanates containing isocyanurate groups (German Patent 10 22 798, German Patent 12 22 067, German Patent 10 27 394, German Published Application 19 29 034, and German Published Application 20 04 048), polyisocy-anates containing urethane groups (Belgian Patent 752,261, U.S. Patent 3,394,164), polyisocyanates containing biuret groups (German Patent 11 01 394, British Patent 889,050) and polyisocyanates containing ester groups (British Patent ~;
965,474, British Patent 1,072,956, U.S. Patent 3,567,763, German Patent 12 31 688).
Preferably used are the aromatic di- and polyisocy-anates such as 2,4- and 2,6-toluene diisocyanate and any desired mixtures of these isomers, 2,2'-, 2,4'- and 4,4'-di-phenylmethane diisocyanate as well as any desired mixtures of these isomers, mixtures of 2,2'-, 2,4'-, 4,4'-diphenylmethane ~;
diisocyanates and polyphenyl polymethylene polyisocyanates (crude MDI) and polyisocyanates containing carbodiimide, urethane, allophanate, isocyanurate, urea and biuret groups.
The di and polyisocyanates may be used individually or in the form of mixtures.
Preferably used as polyols in the manufacture of the polyurethane integral skin foams are common linear and/or branched polyester polyols and/or polyether polyols having molecular weights of 200 to 8000, preferably 800 to 5000 and in particular 1800 to 3500. However, other hydroxyl group containing polymers having the stated molecular weights may also be used. These include polyester amides, polyacetals i7 and polycarbonates and particularly those produced from diphenyl carbonate and 1,6-hexanediol by means of transesterification.
The polyester polyols may, for instance, be produced from dicarboxylic acid, preferably aliphatic dicarboxylic acids having 2 to 12, preferably 4 to 8, carbon atoms in the alkylene radical and multifunctional alcohols, preferably diols. Examples include aliphatic dicarboxylic acids such as glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and preferably succinic and adipic acid, and aromatic dicarboxylic acids such as phthalic acid and terephthalic acid. Examples of bi and multifunctional, in particular bi and trifunctional, alcohols are: ethylene glycol, diethylene glycol, 1,2- and/or 1,3-propanediol, dipropylene glycol, 1,10-decanediol, glycerol, -trimethylolpropane and preferably 1,4-butanediol and 1,6-hexanediol. If multifunctional, in particular trifunctional, alcohols are used for the manufacture of the polyester polyols, their amount is appropriately calculated in such a manner that the functionality of the eesulting polyester polyols is 2.5 maximum. The polyester polyols have molecular weights of 500 to 5000, preferably of 1000 to 3000, and hydroxyl numbers of 30 to 300, preferably 50 to 100.
Preferably used as polyols, however, are polyether polyols which are manufactured according to familiar processes from one or more alkylene oxides having 2 to 4 carbon atoms in ~ 1588~

the alkylene radical and an initiator molecule containing 2 to 8, preferably 2 to 4, active hydrogen atoms.
Suitable materials include tetrahydrofuran, 1,3-epoxy propane and suitable alkylene oxides including 1,2-or 2,3-butylene oxide, styrene oxide, and preferably ethylene oxide and propylene oxide. The alkylene oxides may be used individually, alternatingly in seguence, or as mixtures.
Possible initiators are: water, organic dicar-boxylic acids such as succinic acid, adipic acid, phthalic acid, and terephthalic acid, aliphatic and aromatic, N-mono-, N,N- and N,N'-dialkyl-substituted diamines having 1 to 4 carbon atoms in the alkyl radical, and mono- and dialkyl substituted ethylenediamines, diethylenetriamines, tri-ethylenetetramine, l,3-diaminopropane, 1,3- and/or 1,4-butanediamine, 1,2-, 1,3-, 1,4-, 1,5- and 1,6-hexanediamine, phenylenediamine, toluene-2,4- and -2,6-diamine and 4,4'-, 2,4'- and 2,2'-diaminodiphenylmethane; monoamines such as methylamines, ethylamine, isopropylamine, butylamine, benzyl-amine, aniline, the tuluidines and naphthylamines. Of the above compounds, the following are of particular interest:
N,N,N' ,N'-tetrakis(2-hydroxyethyl)ethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylene-diamine, N,N,N',Nn,Nn-pentakis(2-hydroxypropyl)ethylenetriamine, phenyldiiso-propanolamine, and higher alkylene oxide adducts of aniline.
Other initiators include alkanolamines such as ethanolamine, diethanolamine, N-methyl and N-ethyl ethanol-:

amines, N-methyl and N-ethyl diethanolamine. and triethanol-amine, hydrazine, and hydrazides. Preferably used are multi-functional alcohols such as ethylene glycol, 1,2- and 1,3-propane glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, l,6-hexane glycol, glycerine, trimethylolpropane, and pentaerythritol. Other applicable polyols are the non-reducing sugars, the non-reducinq sugar derivates and, prefer-ably, their alkylene oxide adducts wherein the alkylene oxides have 2 to 4 carbon atoms. Useable non-reducing sugars and sugar derivates include, for instance, saccharose, alkyl glycosides such as methyl glycoside and ethyl glycoside, and glycol glycosides such as ethylene glycol glycosides, propyl-ene glycoside, glycerine glycoside and l,2,6-hexane triol glycoside.
The polyester amides include, for instance, the primarily linear condensates obtained from multifunctional.
saturated and unsaturated carboxylic acids and/or their anhydrides, and multifunctional saturated and unsaturated amino alcohols or mixtures of multifunctional alcohols and amino alcohols and polyamines.
Possible polyacetals include those compounds which can be produced from glycols such as diethylene glycol, triethylene glycol, 4,4'-dioxethoxydiphenyldimethylmethane, hexanediol and formaldehyde. Polyacetals suitable for application according to the invention can also be produced by the polymerization of cyclic acetals.

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Polycarbonates containinq hydroxyl groups include those of a familiar type which can be produced, for instance, by the reaction of diols such as trimethylene glycol, 1,4-butanediol, and/or 1,6-hexanediol, diethylene glycol, tri-ethylene glycol, tetraethylene glycol with diaryl carbon-ates such as diphenyl carbonate or phosgene.
The polyols may be used individually or in the form of mixtures. Mixtures consisting of polyester and polyether polyols have proven to work particularly well. Depending on the intended application of the polyurethane integral skin foam to be manufactured, the ratio of the components may vary within wide limits, for instance, in a weight ratio of poly-ester polyol to polyether polyol of 20:80 to 80:20.
It may be appropriate to use chain extenders or cross-linking agents for the manufacture of polyurethane integral skin foams in addition to the referenced polyols.
Such agents may include polyfunctional, particularly di and trifunctional, compounds having molecular weights of 17 to 600, preferably 60 to 300. Used, for instance, are di and trialkanol amines such as diethanol amines and triethanol amines, and preferably aliphatic diols and triols having 2 to

6 carbon atoms such as ethylene glycols, 1,4-butanediol, 1,6-hexamethylene glycol, glycerine and trimethylolpropane.
For the manufacture of polyurethane integral skin foams which have a tight, compact outside skin, blowing agents with physical effects are preferably used. Suited for this application are liquids which are inert toward the organic _g_ 1 15~

polyisocyanates and which have boiling points below 100-C, preferably below 50-C, particularly between -50-C and 30-C, at atmospheric pressure so that they evaporate under the influence of the exothermal polyaddition reaction. Examples of such preferably used liquids are hydrocarbons such as pentane, n- and iso-butane and propane, ethers such as di-methyl ether and diethyl ether, ketones such as acetone and methyl-ethyl ketone, ethyl acetate and preferably halogenated hydrocarbons such as methylene chloride, trichlorofluoro-methane, dichlorodifluoromethane, dichloromonofluoromethane,dichlorotetrafluoroethane and 1,1,2-trichloro-1,2,2-trifluoro-ethane. Mixtures of the~e low boiling liquids with each other and/or with other substituted or unsubstituted hydrocarbons may also be used. Water, which reacts with isocyanate groups by forming carbon dioxide, may possibly also be use~ as blowing agent.
The required quantity of blowing agent having a physical effect can be determined simply as a function of the desired foam density and is approximately 2.5 to 20 percent by weight, preferably 5 to 15 percent by weight, relative to the polyol weight.
Suitable mixtures of halogenated hydrocarbons and water generally consist of 2.5 to 20 percent by weight, preferably 5 to 10 percent by weight, of halogenated hydro-carbons and 0.01 to 1.5 percent by weight, preferably 0.1 to 1 percent by weight, of water with the percentages by weight being relative to the polyol weight.

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: . ,; ' ~1~8~7 Preferably used for the manufacture of the integral skin foams are trichlorofluoromethane, and methylene chloride or mixtures of these blowing agents in a ~uantity of 2.5 parts to 20 parts by weight per 100 parts by weight of polyol. The water content, if water is used, is generally smaller than 1 part by weight, preferably 0.01 part to 0.5 part by weight relative to 100 parts polyol.
Suitable catalysts for accelerating the reaction of polyols, possibly water and chain extenders, and the polyiso-cyanates include tertiary amines such as dimethylbenzyl-amine, N,N,N'-N'-tetramethyldiaminoethylether, bis-(di-methylaminopropyl)-urea, N-methyl and/or N-ethylmorpholine, dimethylpiperazine, 1,2-dimethylamidizole, 1-azo-bicyclo-(3,3,0)-octane as preferably triethylene diamine, metal salts such as tin dioctoate, lead octoate, tin diethylhexoate, and preferably tin-(II)-salt, and dibutyltin dilaurate as well as mixtures consisting of tertiary amines and organic tin salts.
Preferably used are 0.1 to 2 percent by weight of catalysts based on tertiary amines and/or 0.01 to 0.2 percent by weight of metal salts relative to the polyol weight.
Auxiliaries and additives which are commonly used for the manufacture of polyurethane foams may also be incor-porated in the foamable reaction mixtures. These include surface active materials, flame retardants, pore regulators, antioxidants, hydrolysis-protection agents, pigments, fillers and other additives.

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Possible surface-active materials include compounds which serve to support the homogenization of the reactants and are possibly also suited to regulate the cell structure of the polyurethane foams. Examples include siloxane alkylene mixed polymerizates and other organo-polysiloxane, oxy-ethylated alkyl phenols, oxyethylated fatty alcohols, paraffin oils, castor oil, resinoleic esters and turkish red oil, which are used in quantities of 0.2 part to 6 parts by weight per 100 parts by weight of polyisocyanate.
In order to improve the flame resistance, flame retardants may be incorporated in the lightfast polyurethane foams manufactured according to this invention. Examples include compounds containing phosphorus and/or halogen atoms which can furthermore reduce the tendency towards brittleness in the foams and which function as plasticizers such as tricresol phosphate, tris-2-chlorethyl phosphate, tris-chloro-propyl phosphate, and tris-2,3-dibromopropyl phosphate, and inorganic flame protection agents such as antimony trioxide, arsenic oxide, ammonium phosphate and others.
It has generally proven to be advantageous to use 1 part to 10 parts by weight of the above-mentioned flame protection agent for 100 parts by weight of polyisocyanates.
More detailed data on the above, and other commonly used auxiliaries and additives are contained in the literature, for instance, the monograph by J. H. Saunders and K. C. Frisch "High Polymers~, Volume XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers 1962 and 1964.

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The other foam components for the manufacture of the foam composites are non-polyurethane foams having densities of -5 grams per liter to 500 grams per liter, preferably 20 grams per liter to 100 grams per liter. These foams may be formu-lated to be either rigid or flexible. Rigid polyurethane integral skin foams are preferably combined with rigid non-polyurethane foams, and flexible polyurethane integral skin foams are combined with flexible non-polyurethane foams.
Suitable rigid non-polyurethane foams include, for instance, phenol-formaldehyde, melamine-formaldehyde and urea-formaldehyde foams as they are described, for instance, by R. C. Frisch, J. H. Saunders, Plastic Foams, Part II, Vol. 1 (1973), Marcel Dekker, New York, 639, 675; polyvinyl chloride foams as described in Plastic Foams, Part I, Vol. 1 (1972) 305; polyamide foams as described in Plastic Foams, Part II, Vol. 1 784; polyester foams, as described in Plastic Foams, Part II, Vol. 1 777; and preferably polystyrene foams as known from C. J. Benning, Plastic Foams (1969) Wiley 1.
Inorganic foams such as silicates, expanded clay, or perlite may also be utilized as the non-polyurethane foam.
Flexible non-polyurethane foams include: rubber latices, as desribed by D. C. Blackley, High Polymer Latices (1966), Maclaren~London, Vol. 2, 583; elastified polystyrene foams as described in R. J. Bender, Handbook of Foamed Plastics (1965), Lako Publishing Corp./Libertyville 240 and preferably polyolefin foams as described in the same reference on page 285.

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Particularly well suited for the manufacture of foam composites are flexible elastic foams of olefin polymers having densities of 10 to 100 grams per liter. Olefin poly-mers are understood to be homo- and copolymers of olefins having 2 to 4 carbon atoms. Olefin homo- and copolymers with X-ray crystallinities of more than 25 percent at 25C are par-ticularly well suited. Thus, for instance, homopolymers of ethylene, propylene and butylene, or copolymers of these monomers may be used in this invention. Particularly well suited are copolymers of ethylene with other ethylenically-unsaturated monomers which appropriately contain more than approximately 50 percent by weight of ethylene. Examples include copolymers of ethylene with 5 to 30 percent by weight, relative to the overall weight of the copolymer of acrylic, methacrylic, or vinyl carboxylic esters having 1 to 6 carbon atoms in the alcohol radical. Among the co-monomers, the esters of acrylic acid of the n- and tertiary butanol and the vinyl acetate are of particular importance. Mixtures of the olefin polymers with each other or with other polymeric compounds may also be used.
Foamed plastic particles of olefin polymers, which are at times referred to as foam particles, are understood to be those parts wherein the cell membranes consist of the olefin polymers. The parts are completely expanded, they contain essentially no blowing agent and can, therefore, no longer be foamed by heating. Parts with a predominant share of closed cells are preferably used for this process. The foam parts are obtained according to familiar technical I 1~88:l~

processes such as by mixing of the olefin polymers with a blowing agent in an extruder and pressing the mixtures through a nozzle with the resulting strand containing blowing agent, possibly being cut after leaving the nozzles prior to foaming. However, it is also possible to use those parts which are obtained by heating mixtures of olefin polymers and those blowing agents which decompose by forming a gaseous product.
If greater heat resistance is required of the foamed plastic particles, it is appropriate to use foamed parts of olefin polymers, particularly of ethylene homopolymers, and ethylene copolymers having a gel component of 10 to BS percent by weight, preferably of 30 to 60 percent by weight. The gel component is understood to be that part by weight of the polymers which is insoluble in solvents at temperatures above the melting point of crystals. In the case of olefin polymers, the gel component is determined, for instance, by heating the particles in toluene to temperatures of lOO-C and filtering and drying the insoluble components.
The foam parts containing the foamed cross-linked components can be obtained according to various methods.
Among these, one method, wherein the foamed close celled parts are treated with high energy radiation has proven to work particularly well. Thus, the parts may be exposed to, for instance, X-rays or electron beams. In the case of one method for manufacture of parts, which is particularly well suited, the fine foamed olefin polymers are treated with electron beams with dosages of approximately between 5 and 60 Mrd. The .

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manufacture of these parts is described, ~or instance, in the French Patent 1,523,988.
The non-polyurethane foams are preferably worked into the foam composites of the invention in the form of agglomerates which are welded or glued to each other and which may contain communicating hollow spaces. Welded agglomerates may be obtained, for instance~ by heating the foamed flexible olefin polymer particles to the softening temperature of the polymer and centering in molds under slight pressure. Appro-priately, the molds should be designed in such a manner thatthe air or other gaseous or liquid components may escape from the mold while the olefin polymer particles are heated but that the foamed olefin polymer particles must remain in the mold. For centering purposes, the parts are heated to temper-atures where at least 25 percent and preferably 50 to 100 percent of the originally crystalline component of the polymer is melted. The olefin polymer particles can be subjected to the pressure during or after the heating process. According to one advantageous mode of operation, the olefin polymer particles are compressed in the form by 5 to 30 percent of the original pouring volume.
Glued agglomerates are obtained by mixing the foamed, flexible olefin polymerizate particles with solvent-free hardenable binders such as unsaturated polyester resins, epoxy resins, polyisocyanates, and polyurethane prepolymers containing isocyanates or hydroxyl groups and then compressing the mixtures in molds by 5 to 30 percent of the original pouring volume. Depending upon the applied pressure, welded ~ ~58~

or glued agglomerates are obtained from foamed flexible olefin polymer particles having densities of approximately 20 to 120 grams per liter and which have interconnected hollow spaces of varying sizes.
The foam composites of this invention are produced in molds. It is appropriate to use molds, the walls of which are solidly connected with the bottom and which may have a moveable cover. Generally, a moveable cover is used, the sides of which overlap the sides of the mold. In this manner, the mold contents can expand to nearly twice the original volume during foaming of the foamable polyurethane integral skin mixture.
The use of such a form is advantageous particularly in those cases where a certain volume is desired for obtaining a certain density during foaming. The form should also be heatable. Molds, the surfaces of which are not smooth but are structured, patterned or are adjusted to the intended purpose of the composite foam in other ways, may also be used. This measure, for instance, makes it possible to increase the slip resistance or to apply other markings. Preferably used, however, are molds with smooth surfaces.
Molds are also understood to be continuously working molding devices which are used, for instance, for the con-tinuous manufacture of molded products made of polyurethane foams, particularly polyurethane integral skin foams. Such devices consist, for instance, of four conveyor belts which are arranged in such a manner that they form a channel. The foamable polyurethane integral skin foam mixture is introduced in this channel at one end. ~he non-pQlyurethane foam is added at an appropriate distance from this end, the material is foamed and the resulting composite foam is discharged at the other end of the channel. The conveyor belts may also be formed as continuous bands of individual molds.
In detail, the foam composites are appropriately manufactured in the following manner: The foamable polyure-thane integral skin foam mixture is produced according to known methods, for instance, according to the prepolymer and preferably according to the one-shot process.
According to the one-shot process, polyol, catalyst, blowing agent, and generally chain extenders or cross-linking agents, auxiliaries and additives are brought to reaction with the organic polyisocyanates at temperatures of 15C to 60C, preferably 20C to 50C, in such quantities that the ratio of hydroxyl groups of the polyols and possibly NCO active hydrogen atoms of the chain extenders and/or cross-linking agents to NCO groups of the polyisocyanates is o.a 1 to 1.2:1, preferably approximately 1 1. When using a mixing chamber with several feed nozzles, the liquid raw materials may be introduced individually or, if the components are solid, in the form of solutions or suspensions and may be mixed in-tensively in the mixing chamber. However, it has proven to be particularly useful to work according to the two-component process and to use a mixture of polyol, catalyst, blowing agent, possibly chain extending and/or cross-linking agents, auxiliaries and additives as component A and to use the organic polyisocyanates as component B.
Concerning the manufacture of the polyurethane integral skin foams. we should also like to point out the appropriate literature, for instance, A. Nicolay and others GAK No. 4 (1977), Vol. 30, 226-232 and H. Y. Fabris, Adv. in Urethane Technology, Vol. 2 (~973) pages 203-220.
For the batch-type method for manufacturing the foam composites, the foamable polyurethane integral skin foam mixture is inteoduced into a generally heated, sealable mold.
Before the mixture beings to foam, the non-polyurethane foam is inserted in such a manner that it floats on the foamable mixture and possibly touches the side walls of the mold.
Preferably, however, the non-polyurethane`foam is floated on the foamable mixture in such a manner that the distance between one, two, three or all four side walls of the mold and the non-polyurethane foam is 0.5 millimeters to 10 millimeters, preferably 1 millimeters to 4 millimeters.
Following the process, the mold iB sealed. Upon expansion, the foamable mixture pressures the non-polyurethane foam against the mold cover and encloses it on at least one, possibly on five of six sides, that is, foam composites are obtained which consist of a non-polyurethane foam with a thick compact outside skin of polyurethane integral skin foam on at least one, preferably several, and in particular on five surfaces. By means of the process according to this inven-tion, one obtains a smooth surface of polyurethane integral 1 1~8~7 skin foam. The finished foam composites may be demolded after approximately 3 to 5 minutes. The sealing of the mold causes a degree of compacting of 1 to 4, preferably 1.5 to 3.
For the continuous process, the molds are replaced by metal bands with the bottom and the side bands being arranged in a tub-like fashion. The foamable polyurethane integral skin foam mixture is allowed to flow on to the bottom band. The non-polyurethane foam, which advantageously has the form of a foam band, is introduced into the mold in such a manner that it floats on the foamable mixture. The length of the preferably tunnel-shaped mold and the throughput are adjusted to each other in such a manner that the completed foam composite can be removed at the end of the mold.
The foam composites consisting of polystyrene foams and rigid polyurethane integral skin foams combine the low-density and the low price of the polystyrene foam with the high quality wood-like properties of the duromer foam.
Correspondingly produced foam composites are suited as ~wood"
decor, separating elements, wall and furniture parts.
Foam composites of rigid, polyurethane integral skin ~;
foams and foamed phenol-formaldehyde, urea-formaldehyde and/or ;~
melamine-formaldehyde foams, possibly in combination with inorganic foams such as silicate foams, combine the good burning behavior of the non-polyurethane foam with the favor-able physical properties of the polyurethane component.
Such foam composites are primarily used in the construction -;
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industry where good thermal insulation and low flammability properties are required.
The following examples illustrate the invention.
The parts referred to in the examples are parts by weight.

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Example 1 Component A:
73.9 parts of a polyester polyol consisting of succinic, glutaric and adipic acids, ethylene glycol and di-ethylene glycol having a hydroxyl number of 56 and a viscosity of 600 mPa.s at 75-C are mixed with 10.2 parts of ethylene glycol 0.8 part of a 33 percent solution of triethylenediamine in dipropylene glycol 100.68 part of silicone oil (Tegostab-B 2888, anhydrous) 10.0 parts of trichlorofluoromethane 2.5 parts of trichlorotrifluoromethane 2.5 parts carbon (Printex-60) and 0.005 part of dibutyltin dilaurate until the mixture is completely homogenized.
Component B:
For the manufacture of an isocyanate group-con- -taining prepolymers, 33.33 parts of a polyester polyol based on adipic acid, diethylene glycol and trimethylolpropane, with 20 an average functionality of 2.6, an OH number of 50 to 55 and a viscosity of 1300 mPa.~ at 75-C are reacted with a mixture of 54.17 parts of 4,4'-diphenylmethane diisocyanate and 12.50 parts of a commercially available carbodiimide-modified 4,4'-diphenylmethane diisocyanate (Desmodur-CD) at a tempera-ture of 80-C within 2 hours. An isocyanate group-containing carbodiimide-modified prepolymer having an NCO content of 20.6 ,~
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percent by weight and a viscosity of 2400 mPa.s at 20-C was obtained.
Component A is heated to 27-C and component B to 35-C and the two are mixed in a weight ratio of 100:84 by means of a low-pressure foaming machine The free-foaming reaction mixture has a cream time of 6 to 8 seconds and a rise time of 35 to 40 seconds. The growth density is 80 grams per liter.
130 grams of this reaction mixture are fed into an aluminum plate mold of dimensions 260 x 210 x 40 millimeters which has been heated to 45-C and which has been sprayed with a mold-release agent. Before the mixture begins to foam, a panel of polyethylene particle foam (NeopolenN 1710) having dimensions of 255 x 205 x 33 millimeters is floated on the foamable mixture, the foam is sealed and the resulting foam combination is demolded after three minutes. The result is a foam panel consisting of 80 volume percent of polyethylene foam and 20 volume percent of polyurethane integral skin foam (density 250-300 grams per liter) which ha8 an average density of 110 grams per liter and which has an outside layer of polyurethane integral skin foam on five sides. The mechanical properties of the individual foams and the composite foams are summarized in Table 1.
Example 2 Component A:
74.6 parts of a polyester polyol consisting of succinic, glutaric and adipic acid as well as ethylene glycol and ~;

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trimethylolpropane having an OH number of 55 to 59 and varying functionality are mixed with 12.0 parts of a 15 percent pigment paste in ethylene glycol 0.5 part of a 33 percent solution of triethylenediamine in dipropylene glycol 0.075 part silicone oil (Tegostab~B 2888, anhydrous) 10.0 parts of trichlorofluoromethane and 2.5 parts trichlorofluoroethane until the mixture is totally homogenized.
The polyester polyols used have a functionality of 2.2 and a viscosity of 900 mPa.s at 75-C or a functionality of 2.4 and a viscosity of 1300 mPa.s at 75-C.
Component B:
For the manufacture of isocyanate group-containing prepolymers, 33.33 parts of a polyester polyol based on succinic acid, glutaric acid and adipic acid as well as ethylene glycol and trimethylol propane with an OH number of 55 to 59 and functionalitites of a) 2.2, viscosity: 990 mPa.s at 75-C
b) 2.4, viscosity: 1200 mPa.s at 75-C
c) 2.6, viscosity: 1700 mPa.s at 75-C
are brought to reaction with a mixture consisting of 54.17 parts of 4,4'-diphenylmethane diisocyanate and 12.50 parts of a commercially available carbodiimide-modified 4,4'-diphenylmethane diisocyanate at a temperature of 80-C within two hours.

The results are isocyanate-group containing carbo-diimide-modified prepolymers with the following properties:

Polyester Polyol __ Pre lYmer __ P ~ ---r---NCO-Content Viscoslty Type Functionality % mPa.s (20 C) a 2.220.1 1490 b 2.420.2 1670 c 2.620.5 1840 Components A and B are brought to reaction as described in Example 1 and are worked up with ~ V 1710 to form foam composites.
The mechanical properties of the resulting poly-urethane integral skin foams and the foam composites are within the ranges referred to in Table 1.
Examp_e 3 Component A:
72 parts of a polyether polyol based on propylene oxide/-ethylene oxide having an OH number of 28 and a molecular weight of 4000 18 parts of a polyether polyol based on trimethylol-propane, propylene oxide and ethylene oxide having an OH number of 34 and a molecular weight of 4500 6.7 parts of 1,4-butanediol 0.4 parts of ethylene glycol 1.5 parts of a 33 percent solution of triethylenediamine in dipropylene glycol ~, ~,Od~R~k -25-" ~

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0.02 part of dibutyltin dilaurate and 12 parts trichlorofluoromethane are mixed at 30^C until completely homogenized.
Component B:
4,4'-diphenylmethane diisocyanate is reacted with dipropylene glycol to an NCO group-containing prepolymer having an NCO content of 23 percent by weight.
Components A and B are mixed at a weight ratio of 100:45 at 30-C. The free foaming system has a cream time of 16 seconds and a rise time of 38 seconds. The density of the polyurethane foam is 160 grams per liter.
175 grams of the stated foamable polyurethane mixture are introduced into an aluminum mold having dimensions of 25 x 25 x 4 centimeters (volume 2.5 liters) which was heated to 45-C and was sprayed with a mold-release agent. A
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C polyethylene foam panel ~Ncopel~nw N 1710) having dimensions of 24.8 x 24.8 x 3.25 centimeters is floated on the foamable mixture and the ld is sealed. After demolding (molding time 5 minutes) one obtains a composite panel consisting of 80 volume percent polyethylene foam and 20 volume percent polyurethane integral skin foam having a density of 300 grams per liter which as a foam composite has a density of 84 grams per liter and has a compact outside layer of polyurethane integral skin foam on five surfaces.
The physical properties of the polyurethane integral skin foam layer and the foam composite is within the limits referred to in Table 1.

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Example 4 Component A:
140 parts of a polyol (Caradol-560) with an OH number of 550 and a molecular weight of 300 19 parts of a polyol (Desmophen~3900) with an OH number of 35 and a molecular weight of 5000 parts of trimethylolpropane 0.4 part of a 33 percent solution of triethylenediamine in dipropylene glycol (Dabco-33 LV) 1.6 parts of amine catalyst (Desmorapid~PV) 2 parts of additive OS 710 (Bayer AG) 0.5 part additive SM (Bayer AG) and parts trichloromonofluoromethane are mixed at 30-C
until homogeneous.
Component B:
Mixture of diphenylmethane diisocyanates and poly-phenyl polymethylene polyisocyanates (crude MDI).
Components A and B are mixed at 30-C at a weight ratio of 100:150. The free-foaming polyurethane system has a cream time of 26 Reconds and a rise time of 80 seconds. The density i8 160 grams per liter.
250 grams of thè above-described foamable poly-urethane mixture are fed into an aluminum form having dimen-sions of 25 x 25 x 4 centimeters and having been heated to 45-C and sprayed with a mold-release agent. A phenol-formal-dehyde foam panel having dimensions of 24.8 x 24.8 x 3.25 is floated on the foamable mixture and the mold is sealed.

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The phenol-formaldehyde foam is manufactured cor-responding with the data provided by J. Frados, Plastic Engineering Handbook, 4th Edition, Van Nostrand Reinhold Comp., New York 1976, page 572 and following.
After 10 minutes, the foam composite is demolded.
The result is a composite foam panel 80 volume percent phenol-formaldehyde foam and 20 volume percent polyurethane integral skin foam having a density of 500 grams per liter. The foam composite has a density of 130 grams per liter, and a compact 10 outside layer of polyurethane integral skin foam on five ~
surfaces. ;
The physical properties of the individual com-ponents and the foam composite are summarized in Table 2.

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xa~ele 5 Component A:
parts of a polyether polyol based on ethylenediamine, propylene oxide and ethylene oxide with an OH number of 480 and a molecular weight of 480 are mixed with 48 parts of a difunctional polyether polyol based on propylene oxide-ethylene oxide with an OH number of 30 and a molecular weight of 4000 12 parts of trimethylolpropane 4.4 parts ethylene glycol 0.8 part of an amine catalyst (Desmorapid PV) 3 parts of tridecylammonium oleate and 5 parts trichlorofluoromethane at 30~C until the mixture becomes homogeneous.
Component B:
Mixture of diphenylmethane diisocyanates and polyphenyl polymethylene polyisocyanates (crude MDI).
Components A and B are mixed at a weight ratio of 100:130 at 30C and are allowed to foam freely.
The free-Eoaming system has a cream time of 30 seconds and a rise time of 65 seconds. The density of the resulting polyurethane foam is 180 grams per liter.
250 grams of the foamable polyurethane mixture are introduced into an aluminum plate mold having dimensions of 25 x 25 x 4 centimeters according to Example 4. Floated onto this mixture is a urea-formaldehyde foam panel having a density of 15 grams per liter and dimensions of 24~8 x 24.8 ~ 15881~

x 3.25 centimeters. The mold is sealed. After demolding, a composite foam panel is obtained which has a polyurethane integral skin foam surface on five sides.
The mechanical properties of the individual com-ponents and of the foam composites are summarized in Table 3.

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8 ~ 7 Example 6 250 grams of the foamable polyurethane mixture described in Example 5 are introduced into an aluminum plate form having dimensions of 25 x 25 x 4 centimeters. A foam panel (Styrodur-30) with a density of 30 grams per liter and dimensions of 24.8 x 24.8 x 3.25 centimeters is floated onto the polyurethane mixture and the form is sealed. After five minutes, the foam composite is demolded and a foam composite panel having a core of expanded polystyrene foam (80 volume percent) and an outside layer of polyurethane integral skin foam on five surfaces i8 obtained.
The mechanical properties of the individual com-ponents and the foam composites have been summarized in Table `
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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A foam composite comprising 40 volume percent to 10 volume percent, based on the total volume of the foam composite, of a polyurethane integral skin foam and 60 volume percent to 90 volume percent, based on the total volume of the foam composite, of a non-polyurethane foam, wherein the non-polyurethane foam is enclosed by a dense, compact outer skin of polyurethane integral skin foam on more than two surfaces having a degree of compacting of 1 to 4 and being without a glue or binder layer between the foams.

2. A foam composite of claim 1, wherein the polyurethane integral skin foam is a flexible polyurethane integral skin foam and the non-polyurethane foam is a flexible non-polyurethane foam.

3. A foam composite of claim 1, wherein the polyurethane integral skin foam is a rigid polyurethane integral skin foam and the non-polyurethane foam is a rigid non-polyurethane foam.

4. A foam composite of claim 1, wherein the polyurethane integral skin foam is a rigid polyurethane integral skin foam and the non-polyurethane foam is selected from the group consisting of phenol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, polyvinyl chloride, polyamide, polyester, and polystyrene.

5. A foam composite of claim 1, wherein the polyurethane integral skin foam is a flexible elastic polyurethane integral skin foam and the non-polyurethane foam is selected from the group consisting of rubber latex, elastified polystyrene and polyolefin.

6. A foam composite of claim 1, wherein the poly-uretahne integral skin foam is a flexible elastic polyurethane integral skin foam and the non-polyurethane foam is polyethylene.

7. A gymnastic pad of the foam composite of claim 1, wherein the polyurethane integral skin foam is a flexible elas-tic polyurethane integral skin foam and the non-polyurethane foam is polyethylene.

8. A foam composite of claim 1, wherein the non-polyurethane foam is a six sided non-polyurethane foam enclosed by a dense, compact outer skin of polyurethane integral skin foam, having a degree of compacting between 1 and 4 on more than one of the six sides of the non-polyurethane foam.

9. A process for the manufacture of a foam compo-site of a polyurethane integral skin foam and a non-polyurethane foam comprising:
a. feeding a foamable polyurethane integral skin mixture in its flowable state into a sealable mold in such a quantity that a degree of com-pacting of 1 to 4 is achieved upon foaming, b. adding the non-polyurethane foam to the still flowable polyurethane integral skin mixture, c. sealing the mold, and d. allowing the polyurethane integral skin mixture to foam such that a dense, compact outer skin forms on at least one surface.

10. A process of claim 9 comprising the degree of compacting of 1.5 to 3.

11. A process for making a foam composite of a polyurethane integral skin foam and a non-polyurethane foam com-prising.
a. feeding a foamable polyurethane integral skin mixture onto the bottom band of a tunnel-shaped mold, b. feeding the non-polyurethane foam onto the foamable polyurethane integral skin mixture, c. adjusting the length of the tunnel and throughput of feed materials to obtain the desired foam composite at the product end of the tunnel-sha-ped mold, and d. allowing the polyurethane integral skin mixture to foam such that a dense compact outer skin of polyurethane integral skin foam forms on at least one surface.

12. A process for the manufacture of a foam compo-site of a polyurethane integral skin foam and a non-polyurethane foam comprising either I. a. feeding a foamable polyurethane integral skin mixture in its flowable state into a sealable mold in such a quantity that a degree of compacting of 1 to 4 is achieved upon foaming, b. adding the non-polyurethane foam to the still flowable polyurethane integral skin mixture, c. sealing the mold, and d. allowing the polyurethane integral skin mixture to foam such that a dense, compact outer skin forms on at least one surface, or II a. feeding a foamable polyurethane integral skin mixture onto the bottom band of a tun-nel-shaped mold, b. feeding the non-polyurethane foam onto the foamable polyurethane integral skin mixture, c. adjusting the length of the tunnel and throughput of feed materials to obtain the desired foam composite at the product end of the tunnel-shaped mold, and d. allowing the polyurethane integral skin mix-ture to foam such that a dense compact outer skin of polyurethane integral skin foam forms on at least one surface.

13. The composite of claim 8 wherein the polyurethane integral skin foam is made from a polyether polyol based on propy-lene oxide and ethylene oxide; a polyether polyol based on trime-thylolpropane, propylene oxide and ethylene oxide; butanediol;
and ethylene glycol reacted with an isocyanate group containing prepolymer made from reacting 4,4'-diphenylmethane diisocyanate with dipropylene glycol.

14. The composite of claim 5 wherein the polyurethane integral skin foam is made from a polyether polyol based on ethylenediamine, propylene oxide and ethylene oxide, a difunctional polyether polyol based on propylene oxide and ethylene oxide, tri-methylolpropane and ethylene glycol reacted with an isocyanate mixture of diphenylmethane diisocyanates and polyphenyl polyme-thylene polyisocyanates.

15. The composite of claim 14 wherein the non-polyure-thane foam is a urea formaldehyde foam.

16. The composite of claim 15 wherein the non-polyure-thane foam is an expanded polystyrene foam.