摘要:
Liquid carbodiimide-modified organic polyisocyanates are prepared by reacting a crude polymethylene polyphenylene polyisocyanate containing no more than 70 weight percent diphenylmethane diisocyanate with an isomer mixture of 40 to 100 weight percent 4,4'-, 0 to 50 weight percent 2,4- and 0 to 10 weight percent 2,2'-diphenylmethane diisocyanate and having an average functionality of 2.1 to 2.7 and a free NCO content of at least 30 percent weight percent in the presence of an effective amount of carbodimidization catalyst. Polyisocyanurate-polyurethane foams prepared by reacting the modified polyisocyanates and polyols selected from the group consisting of diethylene glycol and ethylene oxide adducts of trimethylolpropane, trimethylolethane, glycerine, pentaerythritol, .alpha.-methylglucoside, sucrose, toluene diamine and methylene dianiline in the presence of trimerization catalysts exhibit improved compression strengths and K-factors with low friability and smoke density.
摘要:
A stable isocyanurate-modified polyisocyanate prepared by trimerizing an organic polyisocyanate mixture of 45 to 70 percent by weight of diphenylmethane diisocyanate having an isomer mixture of 40 to 100 weight percent, 4,4'-, 0 to 50 weight percent 2,4-, and 0 to 10 weight percent 2,2'-diphenylmethane diisocyanate and from 30 to 55 percent by weight polymethylene polyphenylene polyisocyanate with an isocyanurate content of 20 to 33 percent by weight. Polyurethane isocyanurate foams prepared from the reaction of these isocyanates with active hydrogen compounds selected from the group consisting of diethylene glycol and ethylene oxide adducts of trimethylolpropane, trimethylolethane, and glycerine exhibit good K- factors, low friability and low smoke density.
摘要:
The invention relates to carbodiimide- and/or uretonimine-isocyanurate-containing polyisocyanates, to the process for their preparation, and to microcellular foams prepared therefrom.These compositions may be prepared in the presence of the appropriate catalyst by(a) a partial trimerization of a mixture of polyisocyanate and carbodiimide and uretonimine containing polyisocyanate with trimer catalyst to the desired free isocyanate level,(b) sequential, partial carbodiimidization followed by partial trimerization of a polyisocyanate to the desired free isocyanate level(c) sequential partial trimerization of a polyisocyanate followed by partial carbodiimidization,(d) simultaneous conversion using the mixed catalyst system of carbodiimide and isocyanurate catalysts reacted to the desired free isocyanate level, and(e) blending liquid polyisocyanate with the carbodiimide and uretonimine containing polyisocyanate and isocyanurate containing polyisocyanate to the desired isocyanate level.
摘要:
A method for producing liquid isocyanurate modified Polymeric MDI composition containing a high two-ring MDI content, and foams made therefrom is described. The method comprises trimerizing a polymeric MDI in the presence of catalytically effective amount of a trimerization catalyst to form an isocyanurate containing polyisocyanate having a viscosity of about 100,000 mPas. The trimerization catalyst is thereafter deactivated and the isocyanurate-modified polyisocyanate is blended with a methylene bis(phenylisocyanate) (MDI) to form a final product having a two-ring content of about 60 percent of the total ring content and a viscosity comparable to polymeric MDI. Foams produced using this liquid isocyanurate modified polymeric MDI are of a substantially lighter color than those produced from standard polymeric MDI.
摘要:
The invention relates to elimination of discoloration in polyurethanes, particularly thermoplastic polyurethanes, by the addition to the reaction mixture from 0.01 to 1 percent by weight, based on the isocyanate component, a stabilizer package characterized as BHT and a compound selected from tris(nonylphenyl) phosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, 2,2'-oxamido-bis[ethyl-3(3,5-dit-butyl-4-hydroxyphenyl)]propionate, disteryl thiodipropionate, triisodecyl phosphite, trilauryl trithiophosphite, distearyl pentaerythritol, 2,2'-ethylene bis(4,6-di-tertiarylbutylphenol), octadecyl 3-(3',5'-di-t-butyl-4'-hydroxy phenyl) propionate, 4,4'-thio-bis(2-t-butyl-5-methylphenol), 4,4'-thio-bis(2-t-butyl-5-methylphenol), 2,2'-methylene-bis-(4-methyl-6-t-butylphenol), tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, phenothiazine, tris(2,4-di-t-butylphenyl) phosphite, 4,4'-methylene bis(2,6-di-t-butylphenol), 2,6-di-t-butyldimethyl-aminomethylphenol and blends thereof.
摘要:
Rigid cellular foam compositions characterized by carbodiimide, isocyanurate and urethane linkages are prepared by the reaction of an organic polyisocyanate with certain oxyalkylated Mannich polyols employing an NCO/OH equivalent ratio of from about 2:1 to 10:1. The use of the oxyalkylated Mannich polyols in the amounts stated eliminates the need for carbodiimide and isocyanurate promoting catalysts.
摘要:
The invention relates to an improved process for the preparation of toluene diamine from dinitrotoluene involving hydrogenation of dinitrotoluene with hydrogen gas at elevated temperatures and super atmospheric pressure in the presence of a supported nickel catalyst and carbon monoxide ranging from 0.001 to 0.1 volume percent. The rate of hydrogenation, product quality and yield are improved when hydrogen spiked with small amounts of carbon monoxide was used.
摘要:
Polyisocyanurate polymers are prepared by the polymerization of organic polyisocyanates in organic solvents employing trimerization catalysts. After deactivation of the catalysts and removal of the solvents, these polymers may be dispersed in polyols which are employed for the preparation of cellular and non-cellular polyurethane products displaying improved load bearing properties.
摘要:
Reaction products of an organic polyisocyanate with a reactive diamine such as bis(4-aminocyclohexyl)methane and isophorone diamine, prepared at a temperature of between 135.degree. C. and 200.degree. C., are used to prepare polyurethanes useful for comfort cushioning applications such as automotive seating, furniture, mattresses, and large automotive body panels.