MXPA98002541A - Rigid polyurethane foam, blown with water, that absorbes ener - Google Patents

Abstract

The present invention relates to compositions and a method for producing rigid polyurethane foams, blown with water, which absorb energy. The resulting polyurethane foams are of low density, predominantly of open cells, which exhibit a relatively constant consistency of the compression force in the deviations. Such foams are suitable as alternatives, of light weight, to traditional applications that absorb energy

Description

RIGID PE POLYURETHANE, BLOWN WITH WATER, THAT ABSORBES ENERGY FIELD OF THE INVENTION The invention relates, generally, to rigid compositions of polyurethane foam, which absorb energy. More particularly, the present invention relates to rigid polyurethane foams, blown with water, of predominantly open, low density cells, which can be processed over a relatively wide range and can be used, inter alia, for waste management applications. impact energy from both sides and the head.

BACKGROUND OF THE INVENTION Rigid polyurethane foams, which absorb energy, have become increasingly important in several industries, particularly in the automotive industry, in view of the current strict regulations. Thus, there has been a relatively recent focus on polyurethane foam systems, which absorb energy. For example, U.S. Patent No. 4,866,102 discloses rigid, moldable, energy-absorbing polyurethane foam compositions which are prepared by the reaction of a graft polymer dispersion in a% polyoxyalkylene polyether polyol with an alkylene oxide adduct of toluenediamine or diaminodiphenylmethane, and an organic polyisocyanate, in the presence of a crosslinking agent and water with an additional blowing agent. Similarly, the patents of E. U. A., Nos. 4,116,893, 4,190,712, 4,212,954 and 4,282,330,. they also describe dispersions of graft polymers using foams that absorb energy. The patent of E. U. A., No. 4,722,946 describes the production of elastomers and foams of polyurethane, viscoelastic, energy attenuating, comprising mixtures of polyol intermediate products, linear and branched, polyisocyanates and, optionally, diluents, blowing agents and the like, in the presence of a catalyst, whereby the index is varied from isocyanate from 65 to 85, approximately. The patent of E. U. A., No. 4,696,954 describes the preparation of molded polyurethane foams, characterized by high impact resistance and good thermal stability. The patent of E. U. A., No. 4,614,754 discloses a rigid, high density polyurethane foam exhibiting almost constant deformation with increasing stresses in compression. U.A. Patent No. 4,585,807 describes rigid polyurethane foams employing oxyalkylated ethylenediamine. The SAE article 910404, "Fundamental Studies of Polyurethane Foam * for Energy Absorption in Automotive Interiors", discusses, in general, polyurethane foams that absorb energy. Under government regulations every time seniors, who direct the interests of both personal and environmental safety, automakers have placed themselves in a position where they must comply with Wp strict impact requirements, maintain vehicle weight and reduce the use of materials that have an effect harmful in the environment. Rigid polyurethane foams, which absorb energy, have provided a partial solution in some areas of impact performance requirement; for example the energy-absorbing fillers, which can be used to firm the frames of The support of the doors thus helps to preserve the structural integrity of the passenger compartment of a car or as supports that can reduce the effects of secondary collision (interior occupants), however, the foams exhibiting the desired characteristics of the vehicle. impact use generally chlorinated fluorocarbons, such as the foaming or blowing agent. That fact only reduces its convenience due to the mandates to reduce and ultimately eliminate the use of CFCs. In addition, attempts to replace water in foam formulations, particularly for energy absorption applications, they have not had great success. Limited success has been with certain closely defined formulations, which use water as the blowing agent, and which contain a polymer polyol (polyol graft) as the necessary elements of the invention. The U. A. Patents, Nos. 4,190,712, 4,212,954 and 4,116,893, disclose formulations for flexible or viscoelastic foams. Of the known foam formulations, few, if any, can be processed over a relatively broad range, in which the resulting foams can be used for recoverable or deleterious energy management applications. While many polyurethane foam compositions that absorb energy are known in the art, there seems to be a need for foam compositions varying in the index from about 50 to 150, offering, among other improvements, an expanded process intertrust. By an expanded process range it is meant that the foam compositions of the present invention have a wider range of demold times and a wider mold temperature, and pressure capabilities with minimal sacrifice, if any, in the performance of the foam.

COMPENDIUM OF THE INVENTION The present invention relates to rigid compositions of polyurethane foam, which absorb energy, the process for preparing foams and articles. resulting from the manufacture, for example components of side impact and impact of the head for automotive applications. The foams of the present invention are rigid polyurethane foams, which absorb energy, from predominantly open cells, essentially free of chlorinated fluorocarbons and volatile organic carbon blowing agents. While the foams of the present invention are essentially free of chlorinated flourocarbons, these foams have characteristics, such as a resistance to compacted relatively flat and a subsequent minimum spring, p comparable to the rigid polyurethane foams, which absorb energy, which use chlorinated fluorocarbons as the blowing agents, at a rate greater than about 80. Surprisingly, it has been found that they can be produce rigid polyurethane foams blown with water, in association with an active hydrogen-containing component, which has a relatively high propylene oxide content, which exhibits energy-absorbing characteristics comparable to the rigid foams of CFC blowing polyurethane. The foams of the present invention have molding densities ranging from 32 kg / m3 to 160 kg / m3, and a crush resistance that remains relatively flat in an analysis curve of about 30 to 70% in loads up to 5. approximately 10.5 kg / cm2. More particularly, the polyurethane foam of the present invention comprises the reaction product of: flp a) an organic isocyanate; b) a compound containing isocyanate reactive hydroxyl groups, this compound includes at least 50. 0% by weight of oxide, of propylene; c) a catalyst; d) a blowing agent that includes water, in which this water is present in sufficient quantities to cause the formation of a foam of cells predominantly - open, without causing the crushing; and e) optionally, one or more additives, selected from the group consisting essentially of surfactants, crosslinking agents, chain extenders, pigments, stabilizers, fungistats, bacteriostats, fillers and flame retardants. The compound containing isocyanate reactive hydroxyl groups will preferably include between 50 and 80.0% by weight of the propylene oxide. p. The water must be present in sufficient amounts to act as a blowing agent and cell opening agent, which promotes a predominantly open cell structure, not yet present in amounts large enough to cause the foam to flatten. The amount of water used is highly dependent on the other components of the formulation, but it has been found that generally from about 1.0 to 10.0 weight percent is an effective range, a preferred range of water is about 2.0 to 6.5 weight percent. As a result of the present invention, several advantages have been noted which include significant reductions in process costs, due to the savings in weight. For example, the foams of the present invention offer around 25.0% reduction in weight over other foams known for energy management, which have the same physical properties. Still another advantage is a reduction in inventories of the raw material, since a system can be used for the process of multiple foams. Still further, the foams of the present invention offer improved process characteristics, such as a wider process window and improved material flow, leading to a decreased waste rate. The composition of the resin of the present invention has been found is stable with little, if any, separation in time. Additionally, the resulting foams can be processed in different foam machines and / or with different mixing heads, without affecting the wide process window supplied by the foam formulations of the present invention. invention. In addition, as a result of the present invention, the system consistently supplies both production and prototype molded parts, with improved physical properties Wm * and that are aesthetically pleasing. Still other objects and advantages of the present invention will be apparent from a reading of the following detailed description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The polyisocyanates that can be used in the present invention are modified and unmodified polyisocyanates, which are well known to those skilled in the art. technique. For the purposes of this invention, the term polyisocyanate is used to describe compounds containing at least two isocyanate groups. Preferred isocyanates include the 4,4'-diphenylmethane diisocyanate (MDI), mixtures of 4,4 * - and 2,4-diphenylmethane diisocyanates and polymeric polyisocyanates, such as polymethylene polyphenylene polyisocyanates (polymeric MDI). Included within the preferred isocyanates are those modified MDI containing carbodiimide, allophanate, urethane or isocyanurate structures. The isocyanates more Preferred are polymeric MIDs and mixtures of polymeric MDIs and pure 2,4 'and 4,4'-MDI. These polyisocyanates are prepared by conventional methods known in the art, for example the phosgenation of the corresponding organic amine. For the purposes of the present invention, the isocyanates, in addition to the preferred isocyanates, may be present in minor amounts. Useful unmodified polyisocyanates include the aliphatic or cycloaliphatic and aromatic polyisocyanates. Examples include 2,4- and 2, 6-methylcyclohexylene diisocyanate, tetramethylene diisocyanate, cyclohexane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, mixtures of 2,4- and 2,6-toluene diisocyanate, 1,5- Naphthalene diisocyanate, 2, 4-1-methoxyphenyl diisocyanate. In the preparation of the polyurethanes of the present invention, a side resin composition B, which includes a compound containing isocyanate reactive hydroxyl groups, which is reactive with the isocyanate. Certain of the compounds that contain groups Active hydroxyl, useful in the preparation of polyurethanes, are described in the Polyurethane Handbook, in Chapter 3, § 3.1, pages 42-61; and in Polyurethan: Chemistry and Technology in Chapter 11, §§ III and IV, pages 32-47. For example, of the many Hydroxyl-containing compounds that can be used are simple dihydroxy aromatics, bisphenols and polyethers terminated by hydroxyl, polyesters and polyacetals, among others. Lists An extensive list of suitable polyols can be found in many patents, for example in columns 2 and 3 of the patent of E. U. A., No. 3,652,639; columns 2-6 of the patent of E. U. A-, No. 4,421,872; and columns 4-6 of the patent of E. U. A., No. 4,310,632; the disclosures of these three patents are incorporated herein by reference. The compounds containing isocyanate reactive hydroxyl groups, otherwise referred to herein as the isocyanate reactive compounds, will preferably include at least 50.0% by weight of propylene oxide, and more preferably from 50.0 to 80.0% by weight. In addition, the isocyanate reactive compound will have an average system functionality greater than about 2.0 and less than about 4.0, with an average of about 3.0 being preferred. Preferably, the compounds containing isocyanate reactive hydrogen will have a relatively low average viscosity, that is between 1000 and 5000 cps, at about 25sec, and more preferably from 2500 to 3500cps, at about 25ec. Additionally, the average molecular weight for the isocyanate reactive component will be between about 100 and 5000, more preferred between 1000 and 3000 and even more preferred, about 1900. The hydroxyl-terminated polyoxyalkylene polyols may also be employed as long as the component includes active hydroxyl groups, which include at least 50.0% by weight of propylene oxide. Such polyols can be prepared by well-known methods, for example by the catalyzed addition of an alkylene oxide base, preferably ethylene oxide (oxirane) or butylene () ethyloxy) oxide to an initiator molecule containing average two or more active hydrogens, can be used, in accordance with the teachings of the present invention. Examples of preferred initiator molecules are dihydric initiators, such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, hydroquinone, resorcinol and bisphenols, aniline and other aromatic monoamines, monoamines. aliphatics and glycerin monoesters; trihydric initiators, such as glycerin, trimethylolpropane, trimethylolethane, N-alkyl-phenylenediamines, mono-, di- and tri-alkanolanes; tetrahydric initiators, such as ethylene diamine, propylene diamine, 2,4'-, 2,2'- and 4,4'-methylenedianiline, toluenediamine and pentaerythritol; pentahydric initiators, such as diethylenetriamine and hexahydric and octahydric initiators, such as sorbitol and sucrose. The addition of the alkylene oxide to the initiator molecules can take place simultaneously or in sequence, when more than one alkylene oxide is used, resulting in block, heteric and block-heteric polyoxyalkylene polyethers. The number of hydroxyl groups will generally be equal to the number of active hydrogens in the initiator molecule. The processes for The preparation of these polyethers is described both in the manuals Polyurethane Handbook and Polyurethanes: Chemistry and Technology, as in many patents, for example the patents of E. U. A., Nos. 1,922,451; 2,674,619; 1,922,459; 3,190,927 and 3,346,557. The polyester polyols can also be used to form the active hydrogen-containing compounds to be used. These polyesters are well known in the art and can be prepared by simply polymerizing the polycarboxylic acids or their derivatives, for example, its chlorides or acid anhydrides, with a polyol. Numerous polycarboxylic acids are suitable, for example, malonic acid, citric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, terephthalic acid and phthalic acid.

Numerous other polyols are suitable. For example, various aliphatic glycols, trimethylolpropane and trimethylolethane, α-methylglucoside and sorbitol are considered suitable. Also suitable are low molecular weight polyoxyalkylene glycols, such as polyoxyethylene glycol, polyoxypropylene glycol, and polyoxyethylene-polyoxypropylene glycols of block and ether. These lists of dicarboxylic acids and polyols are illustrative i K 'only, and are not intended to be limiting. Methods for The preparation of these polyester polyols is given in the Polyurethane Handbook and in Polyurethane Chemistry and Technology. In a particularly preferred embodiment, it has also been found that acceptable foams are produced by adding only limited amounts of graft polymer dispersions, if any, to the resin component. For the purposes of the present invention, the dispersions of the graft polymer are present in amounts of less than 50% by weight, based on the total amount of the resin on the side B. To the limited extent that the graft polymers, i.e. the graft polyols, are included, the graft polymer dispersions are typically prepared by in situ polymerization in the polyols listed below, of an ethylenically unsaturated monomer or a mixture of S ethylenically unsaturated monomers. Ethylenically representative unsaturated monomers, which may be employed in the present invention, include butadiene, isoprene, 1,4-pentadiene, 1,6-hexadiene, 1,7-octadiene, styrene, α-methylstyrene, 2-methylstyrene, 3- methylstyrene and ethylstyrene 4-, 2, 4-dimethylstyrene, ethylstyrene, isopropyl styrene, butyl styrene, and the like: substituted styrenes such as cyanostyrene, nitrostyrene, N, N- ^ --- SW dimetiletilaminoestireno, acetoxystyrene, 4-vinylbenzoate methyl, phenoxystyrene, p-vinylphenyl oxide, and the like; acrílieos onómeros and the substituted acrylic such as acrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isopropyl methacrylate, octyl methacrylate, methacrylonitrile, a-ethoxyacrylate, methyl a- acetaminoacrilato acrylate, butyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, phenyl methacrylate, N, N- dimethylacrylamide, N, N -dibenzylacrylamide, N, N-dimethyl-20-acrylamide, N, N-dibenzylacrylamide, N-butylacrylamide, methacrylyl-formamide, and the like; vinyl esters, vinyl ethers, vinyl ketones, etc. , such as vinyl acetate, vinyl butyrate, isopropanol acetate, vinyl format, vinyl acrylate, methacrylate, vinyl methoxyacetate, vinyl benzoate, vinyl toluene, vinyl naphthalene, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ethers, vinyl butyl ethers, vinyl 2-ethylhexyl ether, vinyl phenyl ether, vinyl 2-methoxyethyl ether, methoxybutadiene, vinyl 2-butoxyethyl-ether, 3,4-dihydro-1,2-pyran, 2-butoxy-2'--viniloxi diethyl ether, vinyl- methyl ketone, vinyl ethyl ketone, vinyl phosphonates such as vinyl phenyl ketone, vinyl ethyl sulfone, N-methyl-N-vinyl acetamide, N-vinyl pyrrolidone, vinyl imidazole, divinyl sulfoxide, divinyl sulfone, sodium vinyl sulfonate, methyl vinyl sulfonate, N-vinyl pyrrole and the like; dimethyl fumarate, dimethyl maleate, maleic acid, crotonic acid, fumaric acid, itaconic acid, monomethyl itaconate, t-butylaminoethyl methacrylate, dimethylaminoethyl methacrylate, glycidyl acrylate, allyl alcohol, glycol monoesters of itaconic acid, vinyl- pyridine, and the like. Any of the known polymerizable monomers can be used and the compounds listed above are only illustrative of the monomers suitable for use in this invention. Preferably, the monomer is selected from the group consisting of acrylonitrile, styrene and mixtures thereof. The amount of the ethylenically unsaturated monomer used in the polymerization reaction is generally 25 to 60 percent, preferably 30 to 45 percent, based on the total weight of the product. Polymerization # occurs at a temperature between about 25 and ÍSO = C, preferably from 80 to 1352C. The unsaturated polyols or macromers, which can be used in preparing the dispersions of the graft polymer, can be prepared by the reaction of any conventional polyol, such as those described above, with an organic compound, having both F ethylenic unsaturation and a hydroxyl, carboxyl, anhydride, isocyanate or epoxy group, or they can be prepared using an organic compound, having both an ethylenic unsaturation and a hydroxyl, carboxyl, anhydride or epoxy group, or a reagent in the preparation of the conventional polyol. Representative of such organic compounds include the unsaturated mono- and polycarboxylic acids and anhydrides, such as maleic acid and anhydride, fumaric acid, crotonic acid and anhydride, propenyl succinic anhydride, acrylic acid, acryloyl chloride, acrylate or methacrylate. of hydroxyethyl and halogenated maleic acids and anhydrides, polyhydric alcohols unsaturated, such as 2-butene-1, 4-diol, glycerol-allyl ether, trimethylolpropane, allyl ether, pentaerythritol-allyl ether, pentaerythritol vinyl ether, pentaerythritol diallyl ether and 1-butene- 3,4-diol, unsaturated epoxides, such as 1-vinyl-cyclohexene-3,4-epoxide, butadiene monoxide, vinyl-25-glycidyl ether (1-vinyloxy-2, 3-epoxy-propane), methacrylate glycidyl and 3-allyloxypropylene (allyl glycidyl ether). If a polycarboxylic acid or anhydride is used to incorporate the unsaturation in the polyols, it is preferable to react the unsaturated polyol with an alkylene oxide, preferably ethylene or propylene oxide, to replace the carboxyl groups with the hydroxyl groups, before being used in the present invention. Again it should be emphasized that very limited amounts of graft polymers, if any. Illustrative polymerization initiators, which may be employed, are free-radical types, well known, of vinyl polymerization initiators, such as peroxides, persulfates, perborates, percarbonates, azo compounds, etc. They include hydrogen peroxide, dibenzoyl peroxide, acetal peroxide, benzoyl hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, butyryl peroxide, diisopropylbenzene hydroperoxide, eumenohydroperoxide, hydroperoxide of paramentane, diacetyl peroxide, di-a-cumyl peroxide, dipropyl peroxide, diisopropyl peroxide, isopropyl-t-butyl peroxide, butyl-t-butyl peroxide, difuroyl peroxide, bis (triphenylmethyl) peroxide, bis (p-methoxybenzoyl) peroxide, p-monomethoxybenzoyl peroxide, rubenium peroxide, ascaridol, t-butyl peroxybenzoate, diethyl peroxyterephthalate, propyl hydroperoxide, isopropyl hydroperoxide, n-butyl hydroperoxide, t-butyl hydroperoxide , cyclohexyl hydroperoxide, trans-decalin hydroperoxide, a-methylbenzyl hydroperoxide, methyl-a-ethyl-benzyl hydroperoxide, diphenylmethyl hydroperoxide, a, a-azobis - (2-methylheteronitrile), 1-t-butylazo-l-cyanocyclohexene, persuccinic acid, diisopropyl-peroxy-dicarbonate, 2,2'-azobis (2,4-dimethylvaleronitrile), 2-t-butylazo-2- cyano-4-methoxy-4-methylpentane, 2, 2'-azo-bis-2-methylbutane-nitrile, 2-t-butylazo-2-cyanobutane, 1-t-amylazo-l-cyano-cyclohexane, 2, 2 '-azobis (2,4-dimethyl-4-methoxivaleronitrile, 2, 2 * -azobius-2-methylbutyronitrile, 2-t-butylazo-2-cyano-4-methylpentane, 2-t-butylazo-2-isobutyronitrile butylperoxyisopropyl carbonate and the like, a mixture of initiators can also be used. Preferred initiators are 2, 2 * -azobis (2-methylbutyronitrile), '2, 2'-azobis (isobutyronitrile), 2,2-azobis (2,4-dimethylvaleronitrile), 2-t-butylazo-2. -cyano-4-methoxy-4-methyl-pentane, 2-t-butylazo-2-cyano-4-methylpentane, 2-t-butylazo-2-cyano-butane and lauroyl peroxide. In general from 0.1 to 10 percent, approximately, preferably from about 1 to 4 percent by weight of the initiator, based on the weight of the monomer, will be employed, in the process of the present invention.

* Any suitable catalyst or mixture of catalysts can be used, which include tertiary amines such as, for example, triethylene diamine, N-methylmorpholine, N-ethylmorpholine, diethyletolamine, N-5 co-orpholine, l-methyl-4-dimethylaminoethylpiperazine, 3-methoxypropyl dimethylamine, N, N, N'-trimethylisopropyl-propylene diamine, 3-diethylaminopropyldiethylamine, dimethylbenzylamine, and the like. Other suitable catalysts are, for example, stannous chloride, dibutyltin-di-2-ethyl hexonate, potassium hexanoate, stannous oxide, as well as other organometallic compounds, as disclosed in the patent of E. U. A., No. 2,846,408. In some cases, a surface active agent is necessary for the production of the polyurethane foam.

Numerous superficially active agents have been found satisfactory. Of these, well-known nonionic surface active agents, such as silicones, have been found particularly convenient when the use of a tenso-active agent is necessary. Others Agents which are operative, although not preferred, include the polyethylene glycol ethers of long chain alcohols, tertiary amine or alkynol amine salts of long chain alkyl acid sulfate esters, alkyl sulfonic esters, and arylsulfonic acids of alkyl. the use of a The surfactant agent in the present invention is optional.

* A chain extender and / or interleaver may also be employed, in accordance with the teachings of the present invention. They include those compounds which have at least two functional groups which carry active hydrogen atoms, such as hydrazine, primary and secondary diamines, amino alcohols, amino acids, hydroxy acids, glycols or mixtures thereof.

# Other optional additives that are found within the spirit of the present invention include pigments Known, such as carbon black, dyes, stabilizers against aging and weathering, fungistats, bacteriostats, fillers or agents that retard the flame. If desired, you can incorporate agents that retard the flame in the foams. Among these flame retardant agents, which may be employed, are: pentabromodiphenyl oxide, dibromopropinol, tris (β-chloropropyl) phosphate, 2,2-bis (bromoethyl) -1,3-propanediol, tetrakis diphosphate ( 2-chloroethyl) ethylene, tris (2,3-di-20-bromopropyl) phosphate, tris (β-chloroethyl) phosphate, tris (1,2-dichloropropyl) phosphate, bis (2-chloroethyl) 2-chloroethylphosphonate, trioxide of molybdenum, ammonium molybdate, ammonium phosphate, pentabromodiphenyl oxide, tricresuyl phosphate, hexabromocyclododecane and dibromoethyl-dibromocyclohexane.

* - The following illustrates the nature of the invention and should not be construed as limiting the scope of the invention. All quantities are in parts by weight, unless otherwise indicated. Polyol A is an adduct of propylene oxide of ethylenediamine, having a hydroxyl number of 480, theoretical functionality of 4.0 and 87% by weight of propylene oxide.

Polyol B is an adduct of propylene oxide of ethylenediamine, having a hydroxyl number of 767, a theoretical functionality of 4.0 and 79% by weight of propylene oxide.

Polyol C is an adduct of the total ethylene oxide of an aliphatic triol with a hydroxyl number of 920, a theoretical functionality of 3.0 and 0% propylene oxide.

Polyol D is a dispersion, with a solids content of 40%, of an acrylonitrile / styrene copolymer in an adduct of propylene oxide / ethylene oxide of an aliphatic triol, having a general hydroxyl number of 20 30, a theoretical functionality of 3.0 and 88% by weight of propylene oxide.

Polyol E is a dispersion, with a solids content of 30%, of an acrylonitrile / styrene copolymer, in an adduct of propylene oxide / ethylene oxide of an - *. aliphatic triol, having a hydroxyl number of 25, a theoretical functionality of 3.0 and 84% by weight of propylene oxide.

Polyol F is an adduct of propylene oxide co-initiated from an aliphatic diol / tetrol, having a hydroxyl number of 555, a theoretical functionality of 3.5 and 40% by weight of propylene oxide.

Polyol G is an adduct of propylene oxide coinitiated with aliphatic diol / tetrol, having a hydroxyl number of 450, a theoretical functionality of 3.5 and 51% by weight of propylene oxide.

L-550 is a silicone surfactant, commercially available from Union Carbide.

BL-11 is an amine catalyst sold by Air 15 Products. BL-17 is a slow-acting amine catalyst, sold by Air Products. BL-19 is an amine catalyst sold by Air Products.

UAX-6191 is a silicone surfactant.

UAX-6193 is a silicone surfactant.

PC-46 is a catalyst sold by Air Products.

"* P-38 is a catalyst sold by Air Products.

FC-193 is a silicone surfactant sold by Dow Corning.

DEOA is 99% diethanolamine, which has a theoretical hydroxyl number of 1603.

DPG is a dipropylene glycol having a theoretical hydroxyl number of 836.

ISO A is a polymethylene polyphenyl polyisocyanate, having an average nominal functionality of about 2.7 and an isocyanate content of about 32.0% by weight. ISO B is a polymethylene polyphenyl polyisocyanate, which has an average nominal functionality of 3-0, a viscosity of approximately 700 cps at 252C and a β. 15 isocyanate content of approximately 31.0% by weight.

EXAMPLES 1 - 15 T af Sample No. I. Thin pieces well processed, but thick pieces divided apart. 5 2. Well processed minor parts, but more complicated parts did not fill well, due to poor flow characteristics 3. Thin / small pieces well processed, but thick pieces divided apart. 4. It was not processed well. Very poor surface quality. 5. It was not processed well. Healing time too long for most parts. 10 6. System processed well in small parts. Large pieces divided apart. 7. System processed well under controlled conditions (ie, temperatures of components below 38 ° C) 8. System processed well under controlled conditions and in smaller parts. 9. Poor physical properties 15 10. It was not processed well ... all the blocks were divided apart. I I. Not well processed ... intermittently divided blocks 12. Not well processed ... separate divided blocks 13. Acceptable products, but very small process window. 14. Acceptable products but very small process window. 20 15. Wide Process Window and Good Processes As indicated above, the composition of Samples Nos. 13-15 led to foams that exhibited both excellent physical characteristics with Sample No. 15, and that also exhibited the most prosessive interval. large. In this aspect, it was observed that the demolding times varied from 3 to 5 minutes, depending on the geometry and the density of the piece. Additionally, the temperatures of The mold varied from about 38 to 772C and the composition temperatures varied from 26.7 to 492C, without significant changes in the performance of the foam. Resin samples 13 to 15 do not appear to separate over time, have low viscosity and tend to fill complicated geometries of molds without cutting lines, foams or voids. Surprisingly, it was discovered that resulting foams can be adjusted to comply with * different compressive strength requirements, merely altering the water content of the resin. While it will be evident that the preferred embodiments of the invention described, are well calculated In order to comply with the aforementioned objects, it will be appreciated that the invention is susceptible to modifications, variations and changes without departing from its spirit.

Claims (20)

1. ^ - CLAIMS 1. A polyurethane foam, which absorbs energy, which comprises the reaction product of: a) an organic isocyanate; 5 b) a compound containing isocyanate reactive hydroxyl groups, this compound includes at least 50.0% by weight of propylene oxide; c) a catalyst; d) a blowing agent including water, in which this water is present in sufficient amounts to cause the formation of a foam of predominantly open cells, without causing the crushing thereof; and e) optionally, one or more additives, selected from the group consisting essentially of surfactants, 15 interlacing agents, chain extenders, pigments, stabilizers, fungistats, bacteriostats, fillers and flame retardants.
2. 2. The foam of claim 1, wherein a) includes between 50.0 and 80.0% by weight, approximately, 20 of propylene oxide.
3. 3. The foam of claim 1, wherein the foam has a molded density of 32 to 160 kg / m34.
4. The foam of claim 1, wherein a) has an average functionality between at least 32 kg / m3 to less than 64 kg / m3, approximately.
5. 5. The foam of claim 1, wherein a) has an average viscosity between 100 and 500 cps, at a temperature of 252C.
6. 6. The foam of claim 1, wherein a) has an average viscosity between 2500 and 3500 cps, at a temperature of 25se.
7. 7. The foam of claim 1, wherein a) has an average molecular weight between about 100 and 5000.
8. 8. The foam of claim 1, wherein a) has an average molecular weight between 1000 and 3000, approximately.

   9. A resin for use in preparing polyurethane foams, this resin comprises: a) a compound containing isocyanate reactive hydroxyl groups, selected from the group consisting of aliphatic, aromatic dihydroxy glycols, hydroxyl terminated polyethers, polyesters, polyacetals, dispersions of graft polymers and mixtures thereof, wherein the dispersion of the graft polymer is present in * amounts of less than about 50.0% by weight, based on the total weight of the non-isocyanate components; b) a catalyst; c) a blowing agent, consisting essentially of water, in which this water is present in sufficient quantities to cause the formation of a foam predominantly of open cells, without causing the crushing thereof; d) a blowing agent including water, in which this water is present in sufficient amounts to cause the formation of a foam, predominantly of open cells, without causing the collapse thereof; and e) optionally, chain extenders, interlayers, flame retardants, fillers, agents 15 surfactants, fungistats and bacteriostats.

   10. The resin of claim 9, wherein the water is present in amounts of 1.0 to 10.0 weight percent, approximately.

   11. The resin of claim 9, wherein the component a) has an average functionality of more than about 2.0 and less than about 4.0.

   12. The resin of claim 11, wherein component a) has an average viscosity between 2500 and 3500 cps, at a temperature of 25 ° C.

   13. The resin of claim 9, wherein component a) has an average molecular weight between about 100 and 3000.

   14. A method to prepare a rigid polyurethane foam, which absorbs energy, this method comprises: reacting within a closed, preheated mold, a formulation comprising: a) a compound containing isocyanate reactive hydroxyl groups, this compound includes at least 50.0% by weight of the propylene oxide; b) a catalyst; c) a blowing agent, consisting essentially of water, in which this blowing agent is present in an amount sufficient to cause the formation of a foam, predominantly of open cells, without causing the crushing thereof; and d) optionally, chain extenders, interlayers, flame retardants, fillers, surfactants, fungistats and bacteriostats.

   15. The method of claim 14, wherein a) includes between 50.0 and 80.0% by weight, approximately, of propylene oxide.

   16. The method of claim 14, wherein the foam has a molded density that ranges from 32 to 160 kg / m2.

   17. The method of claim 14, wherein a) has an average functionality of at least 32 to less than 64 kg / m2.

   18. The method of claim 14, wherein a) has an average viscosity between 2500 and 3500 cps, at a temperature of 25se.

   19. The method of claim 14, wherein a) has an average molecular weight between 1000 and 3000 ap max.

   20. A rigid article of polyurethane foam, which absorbs energy, having a molded density of 32 to 160 kg / m3 and a relatively constant compression resistance, from 10 to 70% deviation in a load of up to

   4. 9 kg / cm2, which comprises the reaction product of: a) an organic isocyanate; b) a compound containing isocyanate-reactive hydroxyl groups, this compound includes at least

   50. 0% by weight of propylene oxide; c) a catalyst; d) a blowing agent including water, in which this water is present in sufficient quantities to cause the formation of a foam of predominantly open cells, without causing the crushing thereof; and e) optionally, one or more additives, selected from the group consisting essentially of surfactants, crosslinking agents, chain extenders, pigments, stabilizers, fungistats, bacteriostats, fillers and flame retardants. -WP. SUMMARY OF THE INVENTION The invention relates to compositions and a method for producing rigid foams of polyurethane, blown with water, which absorb energy. The resulting polyurethane foams 5 are of low density, predominantly of open cells, exhibiting a relatively constant consistency of the compression force in the deviations. Such foams are suitable as alternatives, of light weight, to traditional applications that absorb energy.