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: A method for producing urethane compounds includes allowing a primary amine, a urea and/or an N-unsubstituted carbamate, and an alcohol to react in the presence of a compound containing a noncoordinating anion and a metal atom as a catalyst.

Abstract: The present disclosure relates, according to some embodiments, to apparatus, systems, and/or methods for fractionating a feed mixture comprising, for example, one or more isocyanates, light components, solvents and/or heavier components. In some embodiments, fractionating an isocyanate feed mixture may comprise distilling the feed mixture in a non-adiabatic fractionating apparatus comprising a prefractionating section and/or column and a main section and/or column, which comprises a rectification section, a side section, and a stripping section. For example, isocyanates may be separated from light component(s), solvent(s) and/or heavier component(s). A fractionating apparatus may be configured and arranged, in some embodiments, as a dividing wall column. According to some embodiments of the disclosure, apparatus, systems, and/or methods may be energy efficient and/or may have a broad operating range.

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: 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: The present invention relates to NCO prepolymers having a low content of free monomeric diisocyanate, to a process for the production of these NCO prepolymers, to polyurethanes prepared from these NCO prepolymers and to processes for the production of these polyurethanes.

Abstract: Bioabsorbable, polyurethane-based stent coatings that comprise non-fouling coatings with polyethylene glycol and hyaluronic acid are disclosed. In addition to these coatings, medical devices comprising these coatings and methods of applying the coatings are disclosed.

Abstract: The invention relates to binder-free spot blender compositions for one- and two-component clearcoat materials comprising at least one isocyanate compound, to processes for producing them, and to their use in automotive refinish.

Abstract: This invention relates to stable liquid, trimer and allophanate-modified isocyanates, a process for the production of these isocyanates, foams prepared from these isocyanates and a process for the production of these foams.

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: 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: Toluenediamine is produced and separated from by-products of the reaction by: a) hydrogenating dinitrotoluene in the presence of a catalyst, b) separating the catalyst, water and optionally solvent from the hydrogenation reaction mixture to give crude toluenediamine, and c) separating by distillation the crude toluenediamine in a separating wall column into at least four product streams P1, P2, P3 and P4. The product stream P1 is a stream containing low boilers. The product stream P2 is a stream containing o-toluenediamine. The product stream P3 is a stream containing m-toluenediamine. The product stream P4 is a stream containing high boilers and m-toluenediamine.

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: 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: 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 novel aromatic isocyanates obtained by partially hydrogenating naphthalene as well as the processes for preparing the same, and to their use as an isocyanate component in the production of polyurethanes.

Abstract: Novel arylisothiocyanate compounds are described that are useful for activating alcohol-containing macromolecules, for example polyethyleneglycols and cellulose, for covalent linkage to amino-groups of biomolecules, for example polypeptides such as antibodies, enzymes, and proteins.

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: 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.

Abstract: There is disclosed a resin composition for electrodeposition paint comprising (A) a resin containing hydroxyl group, and (B) a polyisocyanate compound blocked with an amidoalcohol having at least one amide bond and at least one alcoholic hydroxyl group in the molecule, excellent in storage stability and capable of forming a coating film excellent in low temperature curability.

Abstract: High-functionality polyisocyanates are prepared by a process which comprises

Abstract: A resilient polyurethane foam produced by using a polyether polyol produced by reacting alkylene oxides with a polyhydroxy compound having at least 2 hydroxyl groups as an initiator in the presence of the catalyst for alkylene oxide ring-opening polymerization of the present invention, which is excellent in foam physical properties, vibration characteristics and molding properties.

Abstract: The invention provides a liquid polyisocyanate prepolymer composition which is a result of combining about 50.0 to 90.0 percent by weight of an isocyanate blend (a.) having 55.0 to 75.0 weight percent 4,4′-MDI, 17.0 to 27.0 weight percent 2,4′-MDI, 1.0 to 10.0 weight percent 3-ring MDI oligomer, and 1.0 to 15.0 weight percent n-ring MDI oligomer (n greater than 3); about 5.0 to 30.0 weight percent of a polyhydroxy containing polyol (b.) having a molecular weight of from 700 to about 6,000; and about 15.0 to 75.0 weight percent of a toluene diisocyanate (c.). The resulting isocyanate prepolymer composition has a free NCO content of from about 30.0 to 45.0 weight percent and particularly desirable flow characteristics. The invention further provides a method of making an isocyanate prepolymer composition, a process of making a polyurethane foam utilizing the isocyanate prepolymer composition of the invention, and polyurethane foams produced by the disclosed process.

Abstract: Polyoxyalkylene polyols containing double metal cyanide complexes or residues thereof as are produced during the preparation of polyoxyalkylene polyols by the double metal cyanide complex catalyzed oxyalkylation of a suitably functional hydric initiator are stable without catalyst removal. Isocyanate-terminated prepolymers prepared from such polyols are surprisingly viscosity-stable relative to similar prepolymers prepared from polyols not containing double metal cyanide complexes or residues thereof.

Abstract: This invention relates to novel liquid, homogeneous toluene diisocyanate/polyether/polymethylene poly(phenylisocyanate) prepolymers having an NCO content of from about 2 to 16%, a viscosity or about 10,000 mPa.s or less at room temperature, and which contains about 1.0% or less of free monomeric TDI. This invention also relates to a process for the preparation of these liquid, homogeneous toluene diisocyanate/polyether/-polymethylene poly(phenylisocyanate) prepolymers.

Abstract: Polyoxyalkylene polyols containing double metal cyanide complexes or residues thereof as are produced during the preparation of polyoxyalkylene polyols by the double metal cyanide complex catalyzed oxyalkylation of a suitably functional hydric initiator are stable without catalyst removal. Isocyanate-terminated prepolymers prepared from such polyols are surprisingly viscosity-stable relative to similar prepolymers prepared from polyols not containing double metal cyanide complexes or residues thereof.

Abstract: This invention relates to a process for trimerizing organic polyisocyanates in the presence of thermally active catalyst systems. The catalyst systems comprise (a) compounds selected from the group consisting of 1) lithium salts of aliphatic or aromatic carboxylic acids, 2) lithium salts of hydroxyl group containing compounds wherein the hydroxyl groups are directed attached to an aromatic ring, and 3) lithium hydroxide; used in conjunction with (b) an organic compound which contains at least one hydroxyl group.

Abstract: There is now provided a method of recycling toluenediisocyanate residue resulting from the production of toluenediisocyanate by the reaction of toluenediamine by phosgenation in the presence of a solvent. In accordance with the teachings of the present invention, the toluenediisocyanate residue is treated at reflux with an alkanolamine to obtain an intermediary product which is distilled thereby giving rise to various products including but not limited to at least one component selected from toluenediamine, oxazolidone and hydroxyethylimidiazolidone. Preferably the alkanolamine employed is a monoethanolamine.

Abstract: The present invention relates to polyisocyanates containingi) 0.5 to 10 wt. % of amide and/or imide structural units (calculated as --CO--N.dbd., MW=42),ii) 5 to 20 wt. % of isocyanate groups (calculated as --NCO, MW=42) blocked with blocking agents which are monofunctional in the context of the isocyanate addition reaction andiii) 0 to 30 wt. % of chemically incorporated urethane groups (calculated as --NH--CO--O--, MW=59) obtained from the reaction of isocyanate groups with the hydroxyl groups of organic polyhydroxyl compounds.The present invention also relates to a process for the production of these lacquer polyisocyanates, their use as a binder for stoving lacquers optionally in combination with organic polyhydroxyl compounds and to their use as a binder component containing free hydroxyl groups and optionally blocked isocyanate groups by reacting and/or blending the polyisocyanates with organic polyhydroxyl compounds having a molecular weight of 62 to 350.

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: A TDI residue generated from the phosgenation of toluene diamine having an ortho-isomer content of less than 0.5% is used to produce a urethane-filled hydroxyl compound. The TDI residues useful in this invention must contain at least 10% monomeric TDI and have a total NCO content of at least 20%. These TDI residues are reacted with a monofunctional alcohol in an amount such that the equivalent ratio of isocyanate groups to hydroxyl groups is from about 0.9:1 to about 1:0.9. The resultant composition may then be dissolved in a polyhydroxyl compound to produce a urethane-filled polyhydroxyl compound. This urethane-filled polyhydroxyl compound may then be reacted with a polyisocyanate to produce a polyurethane.

Abstract: Novel difunctionalized cyclobutabenzene monomers of the general formula: ##STR1## wherein Z can be hydrogens or a cyclobutane ring; and X and Y are carboxyl, amino, alcohol, isocyanate, acid halide, or bis-acyl halide groups. Exemplary difunctional bitricyclodecatriene monomers are ?2,2'-bidicyclo?2.4.0!octa-1,3,5-triene!-5,5'-dicarboxylic acid (BXTA) and ?2,2'-bitricyclo?6.2.0.0!deca-1,3,(6),7-triene!-7,7'-dicarboxylic acid (QXTA). The difunctionalized bitricyclodecatriene monomers can form part of a polymer backbone chain in which the multiple butane ring functionalities can be easily opened to produce strong, three-dimensional covalent bond crosslinking between polymer chains. The crosslinking can be induced simply by heating the polymer to a temperature in excess of 250.degree. C.

Abstract: A substantially solid free isocyanate prepolymer is made by reacting an isocyanate mixture which is made up of a toluene diisocyanate residue containing monomeric toluene diisocyanate and optionally, additional monomeric toluene diisocyanate in an amount such that the total NCO content is at least 37% with a polyether polyol having an ethylene oxide content of at least 30%. The polyether polyol has a molecular weight of from about 200 to about 6,000 and a functionality of from 2 to 6. The product prepolymers are particularly useful in the production of polyurethanes.

Abstract: TDI residue-based urethane-filled isocyanate compositions are produced by reacting a TDI residue satisfying specified criteria with a monofunctional alcohol in amounts such that the equivalent ratio of isocyanate groups to hydroxyl groups is from about 0.9:1 to about 1:0.9. This reaction product is then dissolved in a diisocyanate or polyisocyanate. These TDI residue-based urethane-filled isocyanate compositions are particularly useful in the production of polyurethanes.

Abstract: Polyisocyanates based on polyhydroxy polyethers and tolylene diisocyanate containing ether and urethane groups and having an isocyanate group content of from 11.8 to 14.4% by weight, an average isocyanate functionality of from 3.1 to 4.0 and a free tolylene diisocyanate content of less than 0.1% by weight are produced by reacting a polyhydroxy polyether having a molecular weight in the range of from about 350 to about 500 with excess quantities of tolylene diisocyanate and subsequently distilling the mixture to remove unreacted excess of the starting diisocyanate. These polyisocyanates are particularly useful in the production of polyurethane lacquers.

Abstract: A process for producing moldings containing ester and urethane groups and having a cellular core and a compacted surface zone, preferably shoe soles, comprises reactinga) isocyanate semiprepolymers containing ester groups and having an isocyanate content of from 10 to 26% by weight, which in turn are prepared by reactingai) 4,4'-MDI or mixtures of 4,4'-MDI and modified or unmodified MDI isomers,withaii) difunctional to trifunctional polyester polyols having molecular weights of from 600 to 3000 andaiii) at least one branched-chain dihydroxy compound containing at least one bonded ester unit as bridge and having a molecular weight of up to 500,withb) at least one relatively high molecular weight polyhydroxyl compound and, if desired,c) low molecular weight chain extenders and/or crosslinkersin the presence ofd) blowing agents,e) catalystsand, if desired,f) additives in a closed mold with compaction.

Abstract: A process for reducing the amount of residual organic diisocyanate monomer in a polyurethane prepolymer reaction product mixture which comprises distilling the polyurethane prepolymer reaction product mixture in the presence of a combination of at least one inert first solvent with a boiling point below the boiling point of the residual organic diisocyanate monomer and at least one inert second solvent with a boiling point above the boiling point of the residual organic diisocyanate monomer, at a temperature which exceeds the vaporization temperature of the residual organic diisocyanate monomer and which is below the decomposition temperature of the polyurethane prepolymer.

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: A polyisocyanate having an acid value of at least 0.01% HCl is used to produce polyisocyanate, polyisocyanurate and polyurethane urea foams with an HCFC blowing agent. The use of such a polyisocyanate is advantageous because the polyisocyanate does not cause significant decomposition of the HCFC blowing agent.

Abstract: Poly(ether-urethanes) can be made from cyclic ethers and organic isocyanates by using selected metal compounds as catalysts. Polymers useful as thermoplastic elastomers, spandex fibers or urethane rubbers can be made by reacting diisocyanates containing functional groups with a tetrahydrofuran, especially tetrahydrofuran itself. The invention also discloses an improved process for the cationic polymerization of a cyclic ether by using an organic isocyanate.

Abstract: A process for preparing liquid lacquer polyisocyanates with aliphatically and aromatically bound isocyanate groups and an NCO content of 5 to 25 wt. % by trimerizing an isocyanate component A), containing A1) 70 to 100 wt. % of diisocyanatotoluene and A2) 0 to 30 wt. % of other aromatic isocyanates and B) aliphatic lacquer polyisocyanates, optionally with prior, simultaneous and/or subsequent reaction of a portion of the isocyanate groups with an alcohol component C) having a molecular weight of 32 to 900, and optionally in the presence of D) inert solvents; the resulting lacquer polyisocyanates; and their use in coating compositions, in particular as a cross-linking agent for polyhydroxyl compounds in two-component polyurethane coating compositions.

Abstract: A process for producing moldings containing ester and urethane groups and having a cellular core and a compacted surface zone, preferably shoe soles, comprises reactinga) isocyanate semiprepolymers containing ester groups and having an isocyanate content of from 10 to 26% by weight, which in turn are prepared by reactingai) 4,4'-MDI or mixtures of 4,4'-MDI and modified or unmodified MDI isomers,withaii) difunctional to trifunctional polyester polyols having molecular weights of from 600 to 3000 andaiii) at least one branched-chain dihydroxy compound containing at least one bonded ester unit as bridge and having a molecular weight of up to 500,withb) at least one relatively high molecular weight polyhydroxyl compound and, if desired,c) low molecular weight chain extenders and/or crosslinkers in the presence ofd) blowing agents,e) catalystsand, if desired,f) additives in a closed mold with compaction.

Abstract: Isocyanate prepolymers having an NCO content of 1.5 to 5.0 wt. % and a monomeric diisocyanate content of less than 0.5 wt. % which are the reaction products ofA) aromatic or cycloaliphatic diisocyanates withB) mixtures ofB1) polyether polyols having a molecular weight of 1000 to 3000 andB2) polyester carbonate diols having a molecular weight of 700 to 3000,wherein components B1) and B2) are present in a weight ratio of 0.25:1 to 1.5:1;a process for the preparation of these isocyanate prepolymers by reacting the preceding starting materials at an NCO/OH equivalent ratio of at least 1.5:1 and optionally with subsequent removing unreacted monomeric diisocyanate by distillation; and the use of these isocyanate prepolymers as binders for sealing or coating compositions.

Abstract: Compounds of formula I: ##STR1## are disclosed. The compounds are photoinitiators which can be functionalized by means of ethylenic groups or can be bonded to H-active substances, in order, for example, to modify surfaces by means of photopolymerizable substances. The compounds are especially useful in the manufacture of contact lenses.

Abstract: Novel difunctionalized cyclobutabenzene monomers of the general formula: ##STR1## wherein Z can be hydrogens or a cyclobutane ting; and X and Y are carbox amino, alcohol, isocyanate, acid halide, or bis-acyl fluoride groups. In a particularly preferred embodiment, the cyclobutabenzene derivative is 1,2-dihydrocyclobutabenzene-3,6-carboxylic acid. The difunctionalized cyclobutabenzene monomer can form part of a polymer backbone chain, but has an additional functionality, the butane ring, which can be easily opened to produce strong, covalent bond crosslinking between polymer chains. The crosslinking can be induced simply by heating the polymer to a temperature in excess of 300.degree. C.

Abstract: Organic mono- or di-isocyanates are prepared by the decomposition of the corresponding urethanes, by means of a continuous process in which:(a) an urethane flow is continuously fed to a decomposition reactor containing a liquid mixture, composed of a high boiling inert organic solvent, of an unaltered urethane and isocyanate, kept at the boiling conditions of the solvent, at a temperature suitable to decompose the urethane and evaporate the alcohol which is the co-product of the reaction;(b) the liquid mixture is continuously withdrawn from the reactor in (a) and is fed to a flash equipment, at an operating temperature lower than the decomposition temperature of the urethane, where the isocyanate is partially evaporated and the residuous liquid mixture is recycled to the reactor in (a); and(c) the steam flow generated in (b) is distilled to separate the isocyanate in pure or substantially pure form.

Abstract: Xylylene diisocyanate is produced in higher space-time yield with higher selectivity by thermal decomposition of xylylene dicarbamate as an urethane compound, i.e. by subjecting the urethane compound to reactive distillation with a thermal decomposition catalyst of at least one of metals selected from antimony and tin or their compounds in the presence of an inert solvent having a higher boiling point than that of the resulting xylylene diisocyanate under reduced pressure of 1 to 500 mmHg and at 150.degree. to 350.degree. C. and then subjecting the resulting reaction products as distillates to partial condensation outside the reactive distillation system, thereby separately recovering the resulting alcohol and xylylene diisocyanate.

Abstract: Polytetrahydrofuran derivatives of the general formula ##STR1## where n is from 2 to 70, X is the bridge member --NH-- or --O-- and R.sup.1 and R.sup.4 are each hydrogen or various radicals.

Abstract: This invention relates to storage-stable solid isocyanate compositions that are substantially crystalline at room temperature comprising the reaction products of organic isocyanates with substoichiometric quantities of 2-methyl-1,3-propanediol.This invention further to a method of using the solid isocyanate compositions of the invention in the preparation of polyurethane products.