Abstract: Disclosed are novel bioabsorbable and biodegradable monomer compounds, bioabsorbable and biodegradable polymers therefrom, and methods of making such monomers and polymers, which are useful in pharmaceutical delivery systems, tissue engineering applications, tissue adhesives products, implantable medical devices, foams and reticulated foams for wound healing and drug delivery, bone hemostats and bone void fillers, adhesion prevention barriers, meshes, filters, stents, medical device coatings, pharmaceutical drug formulations, consumer product and cosmetic and pharmaceutical packaging, apparel, infusion devices, blood collection tubes and devices, other medical tubes, skin care products, and transdermal drug delivery materials.

Abstract: The present invention relates to a process for manufacturing isocyanates from an amine compound. The process comprises the steps of a) Providing chlorine; b) Providing carbon monoxide; c) Reacting said chlorine and said carbon monoxide for providing phosgene, the carbon monoxide being provided in an adjustable molar excess; d) Providing an amine compound and phosgenating said amine compound using said phosgene thereby providing said isocyanate; the process further comprises adjusting said adjustable molar excess, i.e. the molar excess of carbon monoxide, for adjusting the color of the isocyanate.

Abstract: A prepolymer system has a monomeric isocyanate content of no greater than about 10% by weight based on 100 parts by weight of the prepolymer system. The prepolymer system comprises a diluent component and a prepolymer component different than and separate from the diluent component. The diluent component has an excess of isocyanate (NCO) functional groups, and comprises the reaction product of a monohydric isocyanate-reactive component and an excess of a first isocyanate component. The first isocyanate component comprises monomeric isocyanates reactive with the monohydric isocyanate-reactive component. The prepolymer component also has an excess of NCO functional groups, and comprises the reaction product of a polyol component and an excess of a second isocyanate component. The prepolymer system can be used to prepare foams via reaction with water. The foams have low density and have excellent adhesion and sound dampening properties for use in cavities of automobile bodies.

Abstract: This invention relates to flexible cycloaliphatic diisocyanate trimers and a process for the preparation of these. These flexible products are allophanate-modified, partially trimerized cycloaliphatic diisocyanates and are characterized by a low Tg. More specifically, the Tg of the resultant product ranges from about ?30° C. to about 40° C., after the excess monomer has been removed from the product.

Abstract: The invention relates to liquid polyisocyanate mixtures, to a process for their preparation and to their use in single- and two-component polyurethane coating compositions.

Abstract: The invention relates to polyurethanes that can be obtained by reacting a prepolymer based on diphenylmethane diisocyanate (MDI) with compounds that have NCO-reactive groups, and to use thereof.

Abstract: Absorbable polyurethanes, polyamides and polyester urethanes prepared from at least one compound selected from: or the diamines and diisocyanates thereof, wherein each X represents a member independently selected from —CH2COO— (glycolic acid moiety), —CH(CH3)COO— (lactic acid moiety), —CH2CH2OCH2COO— (dioxanone), —CH2CH2CH2CH2CH2COO— (caprolactone moiety), —(CH2)yCOO— where y is one of the numbers 2, 3, 4 or 6-24 inclusive, and —(CH2CH2O)z?CH2COO— where z? is an integer between 2 and 24, inclusive; each Y represents a member independently selected from —COCH2O— (glycolic ester moiety), —COCH(CH3)O— (lactic ester moiety), —COCH2OCH2CH2O— (dioxanone ester), —COCH2CH2CH2CH2CH2O— (caprolactone ester), —CO(CH2)mO— where m is an integer between 2, 3, 4 or 6-24 inclusive, —COCH2O(CH2CH2O)n— where n is an integer between 2 and 24, inclusive; R? is hydrogen, benzyl or an alkyl group, the alkyl group being either straight-chained or branched; p is an integer between 1 and 4, inclusive; and Rn represents one or more

Abstract: A two-stage process for the preparation of organic isocyanates by reacting primary amines with phosgene in which: a) in a first stage, amine and phosgene are reacted in an adiabatically managed reaction, in which the temperature of reaction is restricted to values between 100 and 220° C. by actively adjusting the absolute pressure in the reactor to values between 8 and 50 bar by decompression, and the temperature is held at values between 100 and 220° C. until the stoichiometric conversion of phosgene has reached at least 80%; and then b) in a second stage, the reaction mixture from a) is decompressed to an absolute pressure of 1 to 15 bar and the reaction mixture is reacted further at temperatures between 90 and 240° C., optionally with the introduction of heat.

Abstract: Isocyanate mixtures comprising: (a) NCO prepolymers having an NCO content of 1.5 to 18 wt. %; and (b) 1 to 40 wt. % of monomeric 2,2?-diisocyanatodiphenylmethane, based on the isocyanate mixture; wherein the isocyanate mixture has a total NCO content of from 2 to 22 wt. %; polyisocyanate polyaddition products prepared therefrom; and methods of making the same.

Abstract: A method for coating a floor, wherein said method comprises applying an aqueous dispersion comprising polyurethane, an acrylate or a hybride or mixture thereof; drying said coating and subjecting the physically dry coating to ultraviolet radiation whereby a cured coating is obtained. Also claimed is reactive additives suitable for use in the methods as well as the floor itself.

Abstract: The present invention relates to a process for preparing an isocyanate, comprising hydrogenating a mixture (Gi) comprising an amine in the presence of a hydrogenation catalyst comprising copper to obtain a mixture (Gii) comprising the amine, and reacting the mixture (Gii) with phosgene to obtain a mixture (Giii) comprising the isocyanate. The present invention further relates to the isocyanate preparable by this process.

Abstract: This invention relates to novel allophanate-modified diphenylmethane diisocyanates, prepolymers of these allophanate-modified diphenylmethane diisocyanates, and two-component polyureas and one-component polyureaurethanes prepared from these prepolymers. In addition, the invention also relates to processes for the preparation of these various compositions, and to the preparation of sealants from the two-component polyureas and caulking agents from the one-component polyureaurethanes.

Abstract: A method for producing toluene diisocyanate is disclosed which comprises forming a dispersion comprising phosgene gas bubbles dispersed in toluene diamine liquid phase, wherein said gas bubbles have a mean diameter less than 1 micron; and subjecting the dispersion to phosgenation reaction conditions, whereby at least a portion of the toluene diamine is phosgenated to form toluene diisocyanate. A system for carrying out the phosgenation of toluene diamine is also disclosed.

Abstract: Solvent-containing formulations including NCO-containing prepolymers based on TDI isocyanurate polyisocyanates and diphenylmethane diisocyanates where some prepolymers are prepared using a polyetherdiol containing ethylene oxide blocks and having an ethylene oxide content of from 2 to 18% by weight, based on all the alkylene oxide units. The formulation have an NCO content of 1% to 7% by weight, a solids content of 20% to 70% by weight, a monomeric TDI content of less than 0.2% by weight and a monomeric methylenediphenyl diisocyanate content of less than 2% by weight. The solvent-containing formulations can be prepared in organic solvents by reacting at least one of A) a TDI component comprising TDI isocyanurate polyisocyanates and B) an MDI component comprising diphenylmethane diisocyanates with C) a polyetherdiol. The solvent-containing formulations can be used in moisture-curing coating compositions, adhesive bonds and/or seals with substrates.

Abstract: It is an object of the present invention to provide an isocyanate group-terminated urethane prepolymer which has a low viscosity at melting and a process for producing the same, and an adhesive which comprises the urethane prepolymer. The invention relates to a process for producing an isocyanate group-terminated urethane prepolymer which comprises reacting polyols with a polyisocyanate compound, wherein the polyols comprise 10 to 50% by mass of a polyester polyol and 90 to 50% by mass of a polycarbonate polyol and wherein a sebacic acid-derived polyester polyol which is a polycondensate of sebacic acid with a diol compound accounts for 50 to 100% by mass of the polyester polyol and wherein the polyisocyanate compound and the polyols are reacted in such amounts that the ratio (by mol) of the isocyanate group/hydroxyl group is 1.2 to 3.2.

Abstract: The present invention provides a method of preparing polymethylene-polyphenyl-polyamine (briefly referred to as polyamine, DAM), in which a high gravity rotating bed is used as the mixing reactor of formaldehyde and aniline hydrochloride, the mixing solution of aniline hydrochloride and circulation solution and the formaldehyde are fed into the high gravity rotating bed reactor proportionally to carry out mixing and condensation reaction under a condition of a very high gravity; the materials leaving the high gravity rotating bed reactor is introduced into a stirred vessel to proceed with the pre-condensation reaction and obtain a condensation solution; and the process steps of heating, molecular rearrangement, neutralization, water washing and purification, etc. are completed to obtain the refined DAM.

Abstract: Dendritic or hyperbranched polyurethanes are prepared by 1) reacting diols or polyols having at least one tertiary nitrogen atom and at least two hydroxyl groups of differing reactivity toward isocyanate groups with diisocyanates or polyisocyanates to form an addition product, with the diols or polyols and diisocyanates or polyisocyanates being selected so that the addition product has, on average, one isocyanate group and more than one hydroxyl group or one hydroxyl group and more than one isocyanate group, 2) converting the addition product from step 1) into a polyaddition product by intermolecular reaction of the hydroxyl groups with the isocyanate groups, and with a reaction with a compound containing at least two hydroxyl groups, mercapto groups, amino groups or isocyanate groups also being able to be carried out first, 3) if desired reacting the polyaddition product from step 2) with a compound containing at least two hydroxyl groups, mercapto groups, amino groups or isocyanate groups.

Abstract: Absorbable polyurethanes, polyamides and polyester urethanes prepared from at least one compound selected from: or the diamines and diisocyanates thereof, wherein each X represents a member independently selected from —CH2COO— (glycolic acid moiety), —CH(CH3)COO— (lactic acid moiety), —CH2CH2OCH2COO— (dioxanone), —CH2CH2CH2CH2CH2COO— (caprolactone moiety), —(CH2)yCOO— where y is one of the numbers 2, 3, 4 or 6-24 inclusive, and —(CH2CH2O)z?CH2COO— where z? is an integer between 2 and 24, inclusive; each Y represents a member independently selected from —COCH2O— (glycolic ester moiety), —COCH(CH3)O— (lactic ester moiety), —COCH2OCH2CH2O— (dioxanone ester), —COCH2CH2CH2CH2CH2O— (caprolactone ester), —CO(CH2)mO— where m is an integer between 2, 3, 4 or 6-24 inclusive, —COCH2O(CH2CH2O)n— where n is an integer between 2 and 24, inclusive; R? is hydrogen, benzyl or an alkyl group, the alkyl group being either straight-chained or branched; p is an integer between 1 and 4, inclusive; and Rn represents one or more

Abstract: This invention relates to storage-stable, liquid, partially trimerized and allophanized polyisocyanates having an NCO group content of 15 to 41% by weight, and comprising 5 to 85% by weight of toluene diisocyanate, 5 to 85% by weight of a polyisocyanate of the diphenyl-methane series and an organic compound or mixture thereof. The present invention also relates to a process for the preparation of the storage-stable, liquid, partially trimerized and allophanized polyisocyanates; to storage-stable, liquid urethane prepolymers of these partially trimerized and allophanized polyisocyanates; and to a process for the production of these storage-stable, liquid, urethane prepolymers.

Abstract: A cyanate ester compound represented by the formula (1), wherein Ar2 represents a phenylene group, a naphthylene group or a biphenylene group, Ar1 represents a naphthylene group or a biphenylene group when Ar2 is a phenylene group, or Ar1 represents a phenylene group, a naphthylene group or a biphenylene group when Ar2 is a naphthylene group or a biphenylene group, Rx represents all substituents of Ar1, each Rx is the same or different and represents hydrogen, an alkyl group or an aryl group, Ry represents all substituents of Ar2, each Ry is the same or different and represents hydrogen, an alkyl group or an aryl group, and n is an integer of 1 to 50.

Abstract: The present invention relates to a process for the production of MDI fractions containing 2,4?-MDI, and in which the 2,2?-MDI component from the MDA production is largely removed from the isomer mixture. Highly reactive monomeric MDI products can be produced in this way. These MDI products are characterised in their processing by significantly reduced emissions of MDI monomers.

Abstract: This invention relates to a novel liquid, storage-stable diphenylmethane diisocyanate which contains allophanate and reactive unsaturation. These novel storage-stable liquids comprise the reaction product of diphenylmethane diisocyanate with an ethylenically unsaturated alcohol, in the presence of an allophanate catalyst and a suitable inhibitor.

Abstract: High-functionality polyisocyanates are prepared by a process which comprises (i) preparation of an addition product (A) which contains one group which is reactive toward isocyanate and at least two isocyanate groups by reacting (a) a diisocyanate or polyisocyanate I with (b1) compounds having at least three groups which are reactive toward isocyanate or (b2) compounds containing two groups which are reactive toward isocyanate or mixtures of (b1) and (b2), where at least one of the components (a) or (b) has functional groups having differing reactivities toward the functional groups of the other component and the reaction ratio is selected so that the addition product (A) contains an average of one group which is reactive toward isocyanate, (ii) if desired, intermolecular addition reaction of the addition product (A) to form a polyaddition product (P) containing an average of one group which is reactive toward isocyanate and an average of more than two isocyanate groups, and (iii) reaction of the addition

Abstract: The invention provides a process for the preparation of polyamines of the diphenylmethane series. This process comprises a) reacting aniline and formaldehyde in a molar ratio of 1.5:1 to 6:1, in the presence of an acid catalyst at temperatures of 20° C. to 100° C., in which the water content in the acid reaction mixture is <20 wt. % and a degree of protonation of <15% is established, and b) increasing the temperature of the reaction to a temperature of 110° C. to 250° C. when the ratio of the weight contents of p-aminobenzylaniline to 4,4?-MDA in the reaction mixture falls below a value of 1.00.

Abstract: A process for preparing methylenedianiline by reacting aniline with formaldehyde in the presence of acid catalysts comprising, in a semicontinuous process, introducing aniline with or without acid catalyst, feeding formaldehyde with or without acid catalyst through a mixing element into a circuit in which aniline with or without acid catalyst and with or without previously added formaldehyde is circulated and, after feeding in at least 50% of the total amount of formaldehyde to be fed in, heating the reaction mixture to a temperature above 75° C. In addition, the invention relates to a process for preparing polyisocyanates by phosgenation of amines obtainable in this manner and to the polyisocyanates obtainable by this process.

Abstract: A polyurethane prepolymer obtainable by reacting at least one aromatic polyisocyanate having symmetrical substitution of NCO groups and at least one aromatic polyisocyanate having asymmetric substitution of NCO groups, the fraction of aromatic polyisocyanate having symmetrical substitution of NCO groups being higher than the fraction of polyisocyanate having asymmetric substitution of NCO groups, and at least one polyol having an OH functionality of more than 2.5 and at least one polyol having an OH functionality of less than 2.5.

Abstract: Polyurethane compositions are produced in a two-stage method. In a first step, a diol component with a molecular weight of less than 2000 is reacted with a monomeric diisocyanate with a molecular weight of less than 500 and the unreacted monomeric diisocyanate is removed from this reaction product. In a second step, the resulting high-molecular diisocyanate is reacted with a polyol to produce a reactive prepolymer with isocyanate and groups. The addition of polyisocyanates which are capable of migration and which have a substantially lower vapor pressure than diphenylmethanediisocyanate, improves the addition behavior of the invention polyurethane compositions. Reactive polyurethane compositions of this type are suitable for using as binding agents for reactive one or two component adhesives/sealants, which may optionally contain solvents. These compositions are also suitable for producing reactive hot melt adhesives when suitable polyols are selected.

Abstract: Process for the purification of toluenediisocyanate from a crude distillation feed which includes toluenediisocyanate, an organic solvent and less than 2% by weight phosgene by separating the crude distillation feed in a dividing-wall distillation column into at least four product fractions P1–P4. P1 is a phosgene enriched low-boiler product, P2 is a solvent-enriched product, P3 is a high boiler enriched bottoms and P4 is a toluenediisocyanate product stream.

Abstract: Toluene diisocyanate is recovered from a crude distillation feed containing less than 2% by weight of phosgene by (a) fractionating the crude distillation feed containing less than 2% by weight of phosgene to remove the solvent and optionally the reaction residues to produce a crude toluene diisocyanate feed containing less than 20% by weight of solvent and (b) separating the crude toluene diisocyanate feed containing less than 20% by weight of solvent in a divided-wall distillation column into four product fractions P1–P4. P1 is a vapor phase low-boiler and solvent-enriched gas stream, P2 is a low-boiler and solvent-enriched product, P3 is a high boiler-enriched bottoms product containing toluene diisocyanate and P4 is a toluene diisocyanate product stream lean in low-boilers, high-boilers and reaction residues.

Abstract: A polyol composition having a number average molecular weight of from about 1,000 to about 3,000 Daltons is made up of (1) at least 60% by weight of a low monol polyoxypropylene polyol having a number average molecular weight of from about 2,000 to 12,000 Da and a degree of unsaturation less than or equal to 0.02 meq/g and (2) no more than 40% by weight of a polyol having a number average molecular weight of from about 400 to about 1,000 Da and a polydispersity index greater than 1.1. This polyol composition is reacted with a diisocyanate, a polyisocyanate, an isocyanate-terminated prepolymer or an isocyanate-terminated quasi-prepolymer to produce polyurethane elastomers having good physical and mechanical properties. Any of the known processes for producing polyurethane elastomers, including one-shot processes, may be used to produce elastomers in accordance with the present invention.

Abstract: The invention relates to a method of producing polyisocyanates of the diphenylmethane series including the steps of a) reacting aniline and formaldehyde in the presence of HCl to provide a product mixture containing polyamines of the diphenylmethane series, HCl, aniline and water; b) removing excess aniline and water by distillation to provide a product mixture comprising polyamines of the diphenylmethane series, HCl, no more than 10 wt. % aniline based on the polyamines, and no more than 5 wt. % water based on the polyamines; and c) phosgenating the product mixture in (b).

Abstract: A fraction of diisocyanates of the diphenylmethane series containing at least 95 wt. % binuclear methylenediphenyl diisocyanate is obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to produce diamines and polyamines of the diphenylmethane series containing binuclear methylenediphenyl diamine, b) phosgenating the diamines and polyamines produced in a), optionally in the presence of a solvent, to produce a crude diisocyanate and polyisocyanate, and c) separating a fraction containing at least 95 wt. % binuclear methylenediphenyl diisocyanate with a 4,4?-MDI content of over 60 wt. %, a 2,4?-MDI content of 4 to 35 wt. % and a 2,2?-MDI content of 0.01 to 10 wt. %, relative to the mass of the fraction, and a maximum of 20 ppm phenyl isocyanate and optionally a maximum of 50 ppm solvent from the crude diisocyanate and polyisocyanate produced in b) in a single distillation step with optional upstream and/or downstream separation of low-boiling components.

Abstract: The present invention relates to a new high functionality MDI. In particular, this invention relates to polymeric allophanates based on diphenylmethane diisocyanate having an NCO group content of 12 to 30%, prepolymers thereof, and processes for the production of these compositions. The prepolymers are stable liquids having NCO group contents of about 10 to about 28%.

Abstract: The present invention relates to a new high functionality MDI. In particular, this invention relates to polymeric allophanates based on diphenylmethane diisocyanate having an NCO group content of 12 to 30%, prepolymers thereof, and processes for the production of these compositions. The prepolymers are stable liquids having NCO group contents of about 10 to about 28%.

Abstract: A process for preparing methylenedianiline by reacting aniline with formaldehyde in the presence of acid catalysts comprising, in a semicontinuous process, introducing aniline with or without acid catalyst, feeding formaldehyde with or without acid catalyst through a mixing element into a circuit in which aniline with or without acid catalyst and with or without previously added formaldehyde is circulated and, after feeding in at least 50% of the total amount of formaldehyde to be fed in, heating the reaction mixture to a temperature above 75° C. In addition, the invention relates to a process for preparing polyisocyanates by phosgenation of amines obtainable in this manner and to the polyisocyanates obtainable by this process.

Abstract: The invention relates to liquid stable MDI prepolymers and curative systems which are suitable for room temperature casting and which yield high performance low-shrinkage urethane elastomers upon room-temperature curing, the prepolymer and curative components, the elastomers themselves, and separately packaged prepolymer component and its complementary curative component provided as a single unit or kit.

Abstract: A process for the purification of toluenediisocyanate by fractionating a crude distillation feed containing toluenediisocyante, an organic solvent and less than 2% by weight of phosgene in a heat integrated system having an upstream distillation column, an interchanger and a downstream distillation column which are connected in series. The vapor which is recovered from the upstream distillation column is used to reboil the bottoms product of the downstream distillation column or the feed to the downstream distillation column in the interchanger. The crude distillation feed comprising less than 2% by weight of phosgene is fractionated into three product fractions P1-P3 and optionally a fourth fraction P4. P1 is a noncondensible gas stream enriched with phosgene and/or low-boilers. P2 is a solvent-enriched product. P3 is a high boiler enriched bottoms product comprising toluenediisocyanate, and P4 is a toluenediisocyanate enriched stream lean in highboilers and reaction residues.

Abstract: The present invention provides a process for quenching a gaseous reaction mixture during the phosgenation of diamines in the gas phase to produce diisocyanates. The gaseous reaction mixture contains at least a diisocyanate, phosgene and hydrogen chloride. The quenching liquid is injected into the gas mixture continuously flowing out of a cylindrical reaction zone into the downstream cylindrical quenching zone with the aid of at least two spray nozzles which are arranged at the entrance to the quenching zone at equal distances along the circumference of the quenching zone.

Abstract: Disclosed is a polyether polyurethane comprising (A) at least one polyisocyanate having two or more isocyanate groups, which is selected from the group consisting of an aromatic polyisocyanate and an aliphatic polyisocyanate; (B) a polyoxytetramethylene glycol (PTMG) having a number average molecular weight of from 500 to 4,000, a molecular weight distribution (Mw/Mn) of 1.75 or less, and a content of high molecular weight PTMG molecules of 10% by weight or less; and (C) at least one chain extender selected from the group consisting of a C2-C10 polyol having two or more hydroxyl groups and a C2-C10 polyamine having two or more amino groups. Also disclosed is a urethane prepolymer which comprises the above-mentioned components (A) and (B) and which has terminal isocyanate groups.

Abstract: The present invention relates to a process for the production of a dinitronaphthalene isomer mixture, in which naphthalene and/or 1-nitronaphthalene is reacted with nitric acid in the presence of a zeolite.

Abstract: Disclosed herein is a process for preparing a reaction product containing methylene diphenylamine, comprising reacting aniline and formaldehyde in the presence of an acid catalyst wherein the acid level of the resulting reaction mixture is reduced during digestion of the reaction mixture.

Abstract: Polyisocyanates of the diphenyl methane series having reduced color values are obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to form a polyamine, b) neutralizing the reaction mixture containing polyamine with a base, c) separating the neutralized mixture into the aqueous and the organic phases, d) adding a base to the organic phase and then e) phosgenating the resulting polyamine to produce the corresponding polyisocyanate.

Abstract: Compounds of formula III, 1

Abstract: In a process for preparing mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates having a reduced content of chlorinated by-products and a reduced iodine color number by two-stage reaction of the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, separation of the excess phosgene and solvent after the phosgenation is complete and thermal treatment of the reaction product, the mass ratios of phosgene to hydrogen chloride in the residence time apparatus of the second stage of the phosgenation are at the same time 10-30:1 in the liquid phase and 1-10:1 in the gas phase.

Abstract: Disclosed are polyester-ether polyols and their use in urethane prepolymers, urethane foams and non-foam urethane coatings, adhesives, sealants and/or elastomers. Methods for producing such polyester-ether polyols are disclosed, along with methods for producing urethane prepolymers. The polyester-ether polyols of the instant invention are preferably the reaction product of phthalic anhydride, diethylene glycol, and propylene oxide. These polyester-ether polyols are useful as either the primary polyol in urethane compositions or in combination with conventional auxiliary polyester- and/or polyether-based polyols. The polyester-ether polyols impart greatly improved solubility and compatibility to mixtures of either polyether and/or polyester polyols. The polyester-ether polyols of the instant invention are desirably of lower viscosity than their precursor intermediate polyester polyols and are generally soluble in either polyester- and/or polyether-based polyols.

Abstract: The invention is directed to polyurethane prepolymers having a reduced amount of unreacted monomeric diisocyanate, particularly diphenylmethane diisocyanate (MDI), prepared by distilling the prepolymer reaction product in the presence of at least one inert solvent whose boiling point is slightly below that of the monomeric diisocyanate; and to high performance cast polyurethane elastomers from the thus obtained prepolymers using diamine and/or diol chain extenders.

Abstract: New, useful and surprisingly effective antiscorch compositions for utilization within polyurethane foam production methods which utilize very popular tertiary amine catalysts are provided. Such compositions require the presence of nominal yet effective amounts of organic cyclic ester materials. The ring systems of such materials appear to open during exposure to heat (during the curing process) and release carboxylic acids into the curing formulation. The tertiary amines become quenched by the carboxylic acids and thus do not exhibit heat destabilization. The resultant foams exhibit extremely low, if no, areas of excessive heating (i.e., scorch) and thus are substantially uniformly colored throughout. The processes and resultant foams are also contemplated within this invention.

Abstract: Polyisocyanates of the diphenylmethane series are produced by a) reacting aniline and formaldehyde in the presence of an acidic catalyst to produce a polyamine, b) neutralizing the reaction mixture from step a) with a base at a temperature of more than 110° C. or neutralizing the reaction mixture from step a) with a base and heating the neutralized mixture to a temperature of more than 110° C., and c) phosgenating the polyamine from step b) to convert it to the corresponding polyisocyanate.

Abstract: This invention relates to storage-stable, liquid, partially trimerized polyisocyanates having an NCO group content of 24 to 40% by weight, and comprising 20 to 88% by weight of toluene diisocyanate and 12 to 80% by weight of a polyisocyanate of the diphenylmethane series. The present invention also relates to a process for the preparation of the storage-stable, liquid, partially trimerized polyisocyanates; to storage-stable, liquid urethane prepolymers of these partially trimerized polyisocyanates; and to a process for the production of these storage-stable, liquid, urethane prepolymers.

Abstract: A low-monomer PU prepolymer containing free NCO groups which is obtained from polyhydric alcohols and diisocyanates differing in their reactivity and which is distinguished by the ratio of the NCO groups of the partly slower-reacting diisocyanate to the NCO groups of the faster-reacting diisocyanate. It is greater than 6:1. Nevertheless the prepolymer according to the invention cures more quickly than a known prepolymer predominantly containing fast-reacting NCO groups. In a preferred embodiment, TDI is used as the partly slower-reacting diisocyanate while MDI is used as the faster-reacting diisocyanate. The prepolymer is produced in two stages. The prepolymer according to the invention is suitable for bonding plastic articles, metals and paper, especially films. The accelerated absence of migration is particularly noticeable in this regard.