Abstract: A one-component polyurethane composition is described that comprises a latent curing agent bonded to the prepolymer, from which curing agent aldehyde is liberated upon curing. Said aldehyde comprises two phenyl groups. By the specific design of the polyurethane composition, the application characteristics as well as the aging resistance of the cured polyurethane are improved.

Abstract: The present invention is an optically clear, high hardness, impact resistant polyurethane which provides exceptionally high heat distortion temperatures and excellent chemical resistance. The invention is particularly useful for transparency applications that require excellent impact resistance coupled with high heat distortion temperatures, such as architectural glazings vehicles, glazings, riot shields, aircraft canopies, face masks, visors, opthalmic and sun lenses, protective eyewear, and transparent armor.

Abstract: A method for the rotational casting of a polyurethane elastomer onto a rotating substrate which comprises mixing a polyurethane prepolymer, an amine curative and optionally a polyol in a mixing head and depositing the mixture onto the rotating substrate, the amine curative comprising:(a) 2-45 wt % aminobenzoate polyol having molecular weight of 200-3,000,(b) 55-98 wt % aromatic polyamine, and(c) 0 to <5 parts by wt carboxylic acid catalyst per hundred parts (a) and (b),the amine curative being at a temperature sufficient to melt the amines when mixed with the polyurethane prepolymer.

Abstract: The oligomers of the present invention are polythioureas having 3 to 50 recurring units derived from aromatic diamines substituted with anionic groups, and having a number average molecular weight of less than 10,000. These oligomers are water-soluble, preferably have a rigid backbone, and are pharmaceutically-acceptable. The oligomers are useful for the treatment and/or diagnosis of AIDS.

Abstract: This invention is a liquid polyisocyanate prepolymer comprising the reaction product of an organic polyisocyanate blend and a polyoxyalkylene polyol, where polyisocyanate blend isA) a diphenylmethane diisocyanate comprising from 50 weight percent to 95 weight percent 4,4'-diphenylmethane diisocyanate, from 5 weight percent to 50 weight percent 2,4'-diphenylmethane diisocyanate, and less than 10 weight percent 2,2'-diphenylmethane diisocyanate, said weight percentages based on the total weight of the ingredients in A);B) a polymethylene polyphenyl polyisocyanate comprising from 30 weight percent to 70 weight percent diphenylmethane diisocyanate, the remainder comprising polymethylene polyphenyl polyisocyanates having functionalities greater than two, said weight percentages based on the total weight of the ingredients in B);C) and optionally a uretonimine-carbodiimide modified diisocyanate comprising from 10 weight percent to 35 weight percent uretonimine-carbodiimide species, the remainder comprising essentia

Abstract: Polurethaneaureas prepared with 2,2-bis(4-isocyanatophenyl)propane or 1,4-bis(4-isocyanato-alpha,alpha-dimethylbenzyl)benzene, and spandex spun from such polyurethaneureas, are provided.

Abstract: Polyurethane prepolymers are disclosed prepared with mononuclear aromatic diisocyanate such as toluene diisocyanate and an aliphatic diisocyanate such as H12MDI. These prepolymers can be cured with 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline) to form a cured urethane elastomer with reduced propensity to crack during the curing process, extended pour life (a slower rate of viscosity buildup after curative and prepolymer are mixed), low hysteresis, and a low level of free toluene diisocyanates and/or other toxic or volatile substances to increase worker safety during processing. It has also been found that prepolymers made from toluene diisocyanate and cured with a blend of two aromatic diamine curatives yields urethane elastomers with the same reduced propensity to crack during the curing process.

Abstract: This invention concerns a method for the preparation of polyurea elastomers, comprising: (a) reacting an amine chain extender with dialkyl maleate to form an aspartic ester, wherein the chain extender has a molar amount of amine groups that is less than the moles of dialkyl maleate; (b) blending the aspartic ester with one or more polyoxyalkyleneamines to prepare a resin blend; (c) contacting the resin blend with an isocyanate under conditions effective to form a polyurea elastomer. This invention also concerns a a polyurea elastomer, comprising the reaction product of (a) a resin blend containing one or more polyoxyalkyleneamine and an aspartic ester and (b) an isocyanate, wherein the aspartic ester in the resin blend comprises a reaction product of an amine chain extender and a dialkyl maleate, wherein the mole ratio of amine functionality in the amine chain extender to dialkyl maleate or fumarate is greater than 1:1.

Abstract: Aliphatic tetraketimine of the present invention are a novel class of compounds represented by the formula: ##STR1## wherein Et is ethyl, Me is methyl, and R is a residue of an aliphatic diisocyanate. The tetraketimine is made by condensing a novel ketimine with a diisocyanate. The ketimine has a free secondary amine after a polyamine selected from the group consisting of:______________________________________ H2N--C2H4--NH--C2H4--NH2, H2N--C2H4--NH--C2H4--NH--C2H4--NH2, H2N--(CH2)6--NH--(CH2)6--NH2, or tris(2-aminoethyl)amine ______________________________________is reacted with a ketone.

Abstract: The present invention relates to polyurethane elastomer systems for industrial and paper mill rolls and more particularly to polyurethane covered rolls made from a new polyurethane composition of a polyurethane prepolymer cured with an aromatic diamine and a hydroxyl-terminated polybutadiene resin. Rolls made with this new polyurethane composition exhibit improved dynamics, hydrolytic stability, and reduced water vapor transmission over conventional polyurethane elastomer systems.

Abstract: A coating composition comprising a solution in a volatile organic solvent of: a polyisocyanate, a reactive diluent having amine groups or blocked amine groups, and a hydroxyl functional compound which is a polyester having secondary hydroxyl groups.

Abstract: The present invention is an optically clear impact resistant polyurethane which provides exceptionally high heat distortion temperatures and excellent chemical resistance. The invention is particularly useful for transparency applications that require excellent impact resistance coupled with high heat distortion temperatures, such as glazings for buildings, vehicles, riot shields, aircraft canopies, and face masks.

Abstract: Spray polyurea elastomer systems have improved adhesion to a substrate with the incorporation of a functional alkoxy silane and water. Such systems typically also include a quasi-prepolymer of an isocyanate and an active hydrogen-containing material, and at least one amine resin, and preferably an amine-terminated chain extender. The system may also benefit from the incorporation of a higher than usual proportion of 2,4'-isomer methylene diisocyanate (MDI). The viscosity of the various components, as well as various processing characteristics, may be improved by the addition of an alkylene carbonate. The spray polyurea elastomer systems of this invention also have improved abrasion and impact resistance.

Abstract: A process for making clear elastomers is disclosed. First, a polyol having a narrow molecular weight distribution (Mw/Mn<1.5) reacts an aromatic diisocyanate at an NCO/OH ratio from about 1.3 to about 3.0 to give a non-viscous isocyanate-terminated prepolymer. A mixture that contains this prepolymer and an aliphatic diisocyanate is then reacted with an aromatic diamine to give a clear elastomer. The elastomers have excellent overall physical and mechanical properties, including resilience greater than 55%. The elastomers are valuable for in-line skates and other applications for which clarity is important.

Abstract: Cast polyurethanes are preferably formed from a hydrogenated polydiene diol having from up to 2 terminal hydroxyl groups per molecule and a number average molecular weight between 1000 and 20,000, an isocyanate having two or more isocyanate groups per molecule. This composition is then reacted with an amine curing agent at 80 to 130.degree. C. to form a cast elastomer with excellent hydrolytic stability. The amine curing agent must be a hindered aromatic amine crosslinker with low polarity and a solubility parameter of less than 10.5.

Abstract: The invention relates to adhesive compositions based on polyurethane and on a polyamine suspension, characterized in that the free isocyanate functional group content is between 2 and 9% by weight and the polyamine is in the form of particles of mean diameter between 30 and 60 .mu.m. Its subject-matter is also a process for the preparation of the said compositions which consists in reacting a polyol and a polyisocyanate to form a polyurethane prepolymer, which prepolymer is mixed with the polyamine suspension.Such compositions can be employed for the adhesive bonding of materials especially for motor vehicles.

Abstract: A process for the preparation of a polyurethane-urea elastomer having a mole ratio of NCO groups to all active hydrogen atoms in the range of 0.9 to 1.2 is disclosed. The process comprise reacting (A), (B) and (C.2) for form an NCO-containing prepolymer and then reacting said prepolymer with (C.1) and (D). Accordingly (A) is 5-isocyanato-1-(isocyanatomethyl)-1,1,3-trimethylcyclohexane or bis-(4-isocyanatocyclohexyl)-methane,(B) is polytetrahydrofuran or hexanediol polycarbonate and (C.2) is a chain extender. (C.1) is 5-amino-3-amino-methyl-1,3,3-trimethylcyclohexane or bis-(4-aminocyclohexyl)-methane and (D) is a molecular weight regulator. The elastomer thus produced is particularly suitable for the preparation of moldings, films, flexible tubing (for medical purposes) and catheters.

Abstract: A polyurethane composition comprising:a) an isocyanate-terminated polyurethane prepolymer; andb) a curative agent comprising i) a polyol; ii) an aromatic diamine; iii) a thixotropic aliphatic amine; and iv) a thixotropic colloidal additive. This composition is useful for coating cylindrical objects.

Abstract: The invention relates to cold-curing, low-solvent or solvent-free 2-component polyurethane/polyurea compositions comprising a reaction product of:a) a diamine of the following composition ##STR1## where R is a linear, branched or cyclic alkylene radical having 2-16 carbon atoms which may be optionally substituted by C.sub.1 -C.sub.4 alkyl, wherein in said alkylene radical 1-3 CH.sub.2 groups may optionally be replaced by ##STR2## groups; and b) one or more NCO prepolymers prepared from reaction of one or more linear, branched or cyclic aliphatic isocyanates and one or more branched polyetherpolyols or polyesterpolyols, wherein the NCO prepolymer has an NCO functionality .gtoreq.2;wherein reactants a) and b) are reacted in an NCO:NH equivalent ratio of (1.5-1):1 and their use as coatings and reaction coating materials.

Abstract: Spandex-type segmented polyurethane/urea elastomers having exceptional elongation, hysteresis, recovery, and other physical properties are prepared by the amine chain extension of an isocyanate-terminated prepolymer prepared by the reaction of a stoichiometric excess of isocyanate with a polyol blend comprising a low molecular weight diol having a molecular weight below 750 Da with a high molecular weight glycol which may be a 1500 Da to 20,000 Da molecular weight, ultra-low unsaturation polyoxypropylene glycol with an unsaturation of less than about 0.010 meq/g.

Abstract: Polyurethane elastic products prepared by a two-stage process are disclosed. In the first stage, polyols are reacted with diisocyanates to form prepolymers. The prepolymers are then reacted with diamine chain extenders which contain amide linkages, to form polyurethane elastic products.

Abstract: An isocyanate-terminated polyurethane prepolymer comprising the reaction product of a polyisocyanate and a polyol composition consisting essentially of a polyether polyol of 350-2000 equivalent weight and a low molecular weight polyol of 62 to<300 molecular weight, in an equivalent ratio of low molecular weight polyol to polyether polyol of 0.25-2.7:1. A polyurethane-urea elastomer having good dynamic properties can be prepared by reacting the isocyanate-terminated prepolymer with an aromatic amine chain extender at an equivalent ratio of 0.9-1.1:1.

Abstract: An extrudable urea-extended thermoplastic polyurethane elastomer is formed from at least one aliphatic diisocyanate, at least one polyester glycol or polyether glycol, and at least one diamine curing agent. At least one second diamine curing agent and/or at least one extrusion processing aid may be included. The polyurethane has high-temperature-resistance and is thus extrudable at high temperatures. The polyurethane is also strong and durable. The polyurethane can be liquid-cast, injection-molded, transfer-molded, sprayed, and extruded without changing either the chemistry or stoichiometry of the polyurethane. The polyurethane may be used for making vehicle air bags or other any application for thermoplastic urethanes which requires increased thermal stability.

Abstract: Spray polyurea elastomer systems have improved adhesion to a substrate with the incorporation of a functional alkoxy silane and water. Such systems typically also include a quasi-prepolymer of an isocyanate and an active hydrogen-containing material, and at least one amine resin, and preferably an amine-terminated chain extender. The system may also benefit from the incorporation of a higher than usual proportion of 2,4'-isomer methylene diisocyanate (MDI). The viscosity of the various components, as well as various processing characteristics, may be improved by the addition of an alkylene carbonate. The spray polyurea elastomer systems of this invention also have improved abrasion and impact resistance.

Abstract: Certain polyester-based polyurethaneureas in solutions of organic solvent at a 12 to 20% concentration are particularly suited for use in a mandrel-dipping process for producing thin-walled elastic articles, such as surgical gloves, which are more resistant to puncture and tear than conventional surgical gloves made from rubber latex.

Abstract: The present invention relates to a coating composition for the preparation of a polyurea coating which containsa) an NCO prepolymer containing aromatically bound isocyanate groups andb) an aldimine corresponding to the formulaX.sub.1 --?N.dbd.CHCH(R.sub.1)(R.sub.2)!.sub.nwhereinX.sub.1 represents an organic group which has a valency of n and is obtained by removing the amino groups from a cyclic organic polyamine having (cyclo)aliphatically-bound amino groups,R.sub.1 and R.sub.2 may be identical or different and represent organic groups which are inert towards isocyanate groups at a temperature of 100.degree. C. or less, or R.sub.1 and R.sub.2 together with the .beta.-carbon atom form a cycloaliphatic or heterocyclic ring, andn represents an integer having a value of at least 2,in which components a) and b) are present in amounts sufficient to provide an equivalent ratio of isocyanate groups to aldimine groups of about 1.0:0.7 to 1.0:0.1.

Abstract: Spandex-type polyurethane/urea segmented elastomers with exceptional physical properties may be prepared by the aliphatic and/or cycloaliphatic diamine chain extension of a solution of isocyanate-terminated polyoxypropylene diol-derived prepolymer wherein the diol component comprises in major part an ultra-low unsaturation polyoxypropylene diol having an unsaturation of less than about 0.010 meq/g and a number average molecular weight greater than 2000 Da. The spandex polymers have commercially desirable percent set and are capable of exceeding the properties of the industry standard PTMEG elastomers in many respects, particularly in elongation and hysteresis.

Abstract: This invention relates to a low-viscosity two-component unfilled polyurethane adhesive having a urethane content of from 10 to 18 percent by weight, based on the weight of nonfilled polyurethane polymer, based on(a) a low-viscosity isocyanate component comprising an organic polyisocyanate in a quantity sufficient to provide an isocyanate index of about 100 to about 150; and(b) a low-viscosity phase-stable curative component comprising(i) 5 to 50 equivalent percent of a polyether polyol and/or a polyether terminated by aromatic amino groups having an equivalent weight greater than 500,(ii) 30 to 95 equivalent percent of 2-methyl-1,3-propanediol, and(iii) 0 to 35 equivalent percent of a chain extender and/or crosslinker other than 2-methyl-1,3-propanediol, with the proviso that the equivalent ratio of component (b)(iii) to component (b)(ii) is no more than about 0.6.

Abstract: Spandex-type segmented polyurethane/urea elastomers having exceptional elongation, hysteresis, recovery, and other physical properties are prepared by the amine chain extension of an isocyanate-terminated prepolymer prepared by the reaction of a stoichiometric excess of isocyanate with a polyol blend comprising a low molecular weight diol having a molecular weight below 750 Da with a high molecular weight glycol which may be a 1500 Da to 20,000 Da molecular weight, ultra-low unsaturation polyoxypropylene glycol with an unsaturation of less than about 0.010 meq/g.

Abstract: A rubber composition comprises a particular copolymer containing isobutylene unit, a paramethylstyrene unit and a parabromomethylstyrene unit; natural rubber and/or diene synthetic rubber; carbon black; and at least one hydrazide compound, and has a low value of tan .delta. at 60.degree. C. with maintaining tan .delta. at 0.degree. C. at a high level.

Abstract: Elastomers with improved physical properties, particularly hardness and rebound, may be prepared by the diamine chain extension or moisture cure of low isocyanate group content, toluene diisocyanate-based prepolymers prepared from a polyol component comprising a high molecular weight, low unsaturation polyoxypropylene diol and a low molecular weight diol. The elastomers are useful for applications such as rollers and other applications where hardness and rebound are important.

Abstract: Substitution of from 5 to 50 equivalent percent of an ultra-low unsaturation polyoxypropylene diol for PTMEG in isocyanate-terminated prepolymers used in spandex production is found to lower considerably both prepolymer viscosity and hysteresis while substantially retaining other desirable physical properties. Such products may offer higher fiber production rates than are possible while employing an all PTMEG-derived polymer.

Abstract: The present invention provides a process for producing a rapidly curable cold-setting polyurethane coating waterproofer which permits the employment of a highly safe aromatic polyamine crosslinker, which is rapidly cured even in the absence of an organometallic catalyst to thereby give a coating film having excellent heat and water resistances, and which can retain a pot life suited for, especially, hand coating. A base composed of an isocyanate-terminated prepolymer comprising the product of reaction between tolylene diisocyanate and a polyoxypropylene polyol and/or a polyoxyethylenepropylene polyol is in-situ mixed with a curing agent containing an aromatic polyamine crosslinker composed of diethyltoluenediamine and a plasticizer, and the obtained mixture is subjected to coating and curing. The plasticizer is contained in the curing agent in an amount of 20 to 130 parts by weight per 100 parts by weight of the prepolymer of the base.

Abstract: This invention relates to a low-viscosity two-component filled polyurethane adhesive comprising(a) a low-viscosity isocyanate component in a quantity sufficient to provide an isocyanate index of about 100 to about 150 comprising an organic polyisocyanate in which up to 10 equivalent percent of the isocyanate groups have been modified by reaction with one or more isocyanate-reactive compounds; and(b) a low-viscosity phase-stable curative component comprising(i) 5 to 50 equivalent percent of a polyether polyol and/or a polyether terminated by aromatic amino groups having an equivalent weight greater than 500,(ii) 30 to 95 equivalent percent of 2-methyl-1,3-propanediol, and(iii) 0 to 35 equivalent percent of a chain extender and/or crosslinker other than 2-methyl-1,3-propanediol, with the proviso that the equivalent ratio of component (b)(iii) to component (b)(ii) is no more than about 0.

Abstract: Allophanate-modified MDI which is a storage stable liquid at 25.degree. C. is produced by reacting a monoisocyanate and an organic material having at least two hydroxyl groups and a molecular weight of from about 60 to about 6,000 to form a urethane. The urethane is then reacted with and isomeric mixture of MDI in an amount such that the product isocyanate will have an NCO content of from about 12 to about 30%. The isomeric mixture of MDI is composed of 4,4'-diphenylmethane diisocyanate containing from 0 to about 60% by weight 2,4'-MDI and less than 6% by weight of the 2,2'-MDI. This allophanate-modified MDI is further reacted with an organic isocyanate-reactive material to produce an allophanate-modified MDI prepolymer containing urethane, urea and/or biuret groups having an NCO content which is generally from about 5 to about 29% by weight. The prepolymers of this invention are particularly useful in reaction injection molding processes because they give molded articles having improved flex modulus.

Abstract: A trimodal molecular weight toluene diisocyanate endcapped polyether polyol prepolymer is disclosed having free toluene diisocyanate below 0.5 weight percent where the three molecular weight polyols used are 300-800, 800 to 1500 and 1500-10000. Processes to make and use these prepolymers as polyurethane castable elastomers having exceptionally long flex fatigue lives using environmentally friendly materials essentially free of TDI are also disclosed.

Abstract: Polyurethane elastomers of improved elongation, tensile strength and other physical properties are prepared from a polyol component containing a crystallizable polyol and from 5 to 35 equivalent percent of a low monol polyoxypropylene polyol by one-shot, quasiprepolymer, and preferably, by prepolymer techniques involving chain extension with an aliphatic diol or aromatic amine.

Abstract: This invention relates to isocyanate-terminated prepolymers, a process for the preparation of these isocyanate-terminated prepolymers, a process for the production of polyurethane.backslash.polyurea elastomers prepared from a diisocyanate comprising these prepolymers, and the elastomers produced by this process. These isocyanate-terminated prepolymers have a viscosity less than about 6000 mPa.cndot.s at 80.degree. C. and an NCO content of about 3 to 10%. These isocyanate-terminated prepolymers are the reaction product ofa) an aromatic diisocyanate,b) a polyether polyol having an OH number of about 25 to 125 and containing from about 1.8 to 2.5 hydroxyl groups, andc) an aliphatic diisocyanate.The equivalent ratio of the polyether polyol to the aromatic diisocyanate is from about 1.0:0.7 to 1.0:1.1.

Abstract: This invention relates to coating compositions containing (A) a polyurethane system containing either a polyurethane containing ionic groups and polyethylene oxide units or a precursor thereof prepared from a blocked isocyanate prepolymer and a cross-linking agent and, optionally, (B) organic solvents. This invention further relates to the use of such coating compositions to prepare coatings that are permeable to water vapor.

Abstract: A coating composition having extended pot-life and excellent cure at ambient conditions. The coating composition comprises (i) at least one imine, (ii) a polyisocynate having an average of at least two isocyanate groups per molecule, (iii) at least one polyaspartic ester, and (iv) an anhydride functional polymer; wherein the coating composition is substantially free of hydroxy functionality.

Abstract: Low molecular weight resins that usually are aliphatic and that include crosslinking thermal functional groups are useful as liquid molding compounds for reaction injection molding or resin transfer molding. The compounds eliminate the need to handle solvents when preparing thermoset composites.

Abstract: A polyurethane and/or polyurethane urea elastomer in the form of a thermostable processable melt, which is immediately processable or which, after cooling and storing, can be remelted and processed. The elastomer is produced by a polyaddition or build-up reaction of longer chain diols with diisocyanate, chain extenders and a polar gelling and/or melting aid for the formation of the thermostable processable melt. A method for manufacturing a polyurethane and/or polyurethane-urea elastomer in the form of a thermally stable processable melt which may be processed immediately or after cooling and storage, being remeltable and reprocessable. The method comprises the steps of: converting n-Mol of a polymeric diol to form a prepolymer with about 1.1 to about 10.0 n-Mol of a diisocyanate at about 50.degree. C. to about 150.degree. C.

Abstract: A diaminourea compound having the formula (I); ##STR1## wherein R.sub.1 and R.sub.2 are independently a straight or branched alkylene group having 2 to 8 carbon atoms, an alicyclic alkylene group having 6 to 15 carbon atoms, a phenylene group, a C.sub.1 -C.sub.4 alkyl-substituted phenylene group, a C.sub.1 -C.sub.4 mono- or di-alkylene substituted phenylene group, or a methanediphenylene group, and a production process thereof as well as a high heat resistant polyurethaneurea derived therefrom and a production process thereof.

Abstract: Allophanate-modified MDI which is a storage stable liquid at 25.degree. C. is produced in two steps. First, a monoisocyanate is reacted with an organic material having about 1.8 or more hydroxyl groups and a molecular weight of from about 60 to about 6,000 to form the urethane. The urethane is then reacted with an isomeric mixture of MDI in an amount such that the resultant isocyanate will have an NCO content of from about 3 to about 28%. The isomeric mixture of diphenylmethane diisocyanate contains from about 0 to about 60% by weight 2,4'-diphenylmethane diisocyanate, less than 6% by weight 2,2'-MDI and the remainder 4,4'-MDI. The prepolymers of this invention are particularly useful in reaction injection molding processes because molded articles having improved flex modulus are obtained.

Abstract: A RIM process utilizing a reaction product of an MDI containing from 6 to 50% by weight of the 2,4'-isomer and a polypropylene glycol as the isocyanate reactant results in a molded product having excellent low temperature impact properties.

Abstract: An epoxy resin composition characterized by comprising (A) an epoxy resin containing an oxazolidone ring, (B) a halogen-containing epoxy resin and (C) a curing agent as its ingredients, wherein the ratio by weight of ingredients (A) to (B) is 5-100:95-0, the hydrolizable chlorine content of ingredients (A) and (B) is no more than 500 ppm and the amount of .alpha.-glycol is no more than 100 m eq/kg has excellent properties and can be employed as the materials for electronic applications and as paints, adhesives, molding materials, composite materials, laminates and sealing materials.

Abstract: Heat generation of a rubber composition can be lowered by incorporating to the composition a compound of the formula, (I), (II) or (III), ##STR1## where A is an aromatic group, hydantoin ring or C.sub.0-18 straight chain hydrocarbon group, B is an aromatic group, X is hydroxy or amino, Y is pyridyl or hydrozino.

Abstract: A process for producing an impact-resistant polyacetal resin composition, which comprises a first step of mixing with shear a polyacetal resin (A), a thermoplastic polyurethane (B) and a polyhydric alcohol (C) having at least three hydroxyl groups in the molecule at a temperature of 180.degree. to 250.degree. C. and at a temperature at which said polyacetal resin (A) and said thermoplastic polyurethane (B) melt; and a second step of mixing with shear the resulting mixture obtained in the first step, in the presence of at least one compound (D) selected from the group consisting of a polyisocyanate (d.sub.1) and a compound (d.sub.2) which generates a polyisocyanate under heat, at a temperature of 180.degree. to 250.degree. C. and at a temperature at which said polyacetal resin (A) and said thermoplastic polyurethane (B) melt.

Abstract: The invention relates to a process for the production of plastics containing amide groups with elimination of CO.sub.2 by reaction of polyfunctional isocyanates, carboxylic acids and, optionally, alcohols in the presence of tertiary amines, more particularly heteroaromatic amines. The heteroaromatic amines preferably contain another heteroatom and/or substituents having +I and/or +M effects. The reaction preferably starts at room temperature. Fine-cell foams having an acid value of less than 40 and a density of at most 150 g/l can be produced in short reaction times at room temperature without any need for additional blowing agents.

Abstract: This invention relates to a process for preparing polyurethane elastomers comprising reacting in an open mold at an isocyanate index of about 90 to about 110(a) an isocyanate prepolymer having an isocyanate content of about 2 to about 15% by weight and a molecular weight of from about 500 to about 5000 prepared by reaction of(i) at least one organic polyisocyanate with(ii) at least one isocyanate-reactive compound having at least two isocyanate-reactive groups and a molecular weight of from about 250 to about 4000;with(b) certain aminocrotonate-terminated polyethers having a molecular weight of from about 500 to about 1500;(c) optional chain extenders and/or crosslinkers other than aminocrotonate-terminated polyether (b); and(d) optional auxiliaries and/or additives.