The invention relates to processes for coating surfaces by alternatingly applying polyisocyanate compositions and suitable crosslinking catalysts, followed by catalytically crosslinking the polyisocyanate composition.

Provided are a method of preparing a polyurethane prepolymer with high functionality and the polyurethane prepolymer with high functionality prepared therefrom and a curing agent comprising the same. The method includes the steps of: Step (A): providing an alcohol composition comprising a first polyol having 2 or 3 OH groups and a second polyol having 4 or more OH groups; Step (B): reacting the alcohol composition with a polyisocyanate to undergo a first polymerization, so as to obtain an intermediate; wherein a molar ratio of a total number of the OH groups of the alcohol composition to a total number of NCO groups of the polyisocyanate is from 1:2 to 1:6; and Step (C): adding a catalyst to carry out a second polymerization of the intermediate to obtain the polyurethane prepolymer with high functionality, which has four or more NCO groups.

The present invention relates to a novel process for preparing isocyanurate-comprising polyisocyanates of (cyclo)aliphatic diisocyanates that are especially stable to color drift in solvents.

The invention relates to a method for producing methylene-diphenylene-diisocyanate and optionally a mixture of methylene-diphenylene-diisocyanate and polymethylene-polyphenylene-polyisocyanate, wherein, in a step ), a fraction (142) containing a methylene-diphenylene-diisocyanate and secondary components is provided, optionally via a step .1), the separating of methylene-diphenylene-diisocyanate and secondary components from a fraction (100) containing methylene-diphenylene-diisocyanate and polymethylene-polyphenylene-polyisocyanate, and wherein, in a step ), the fraction (142) containing methylene-diphenylene-diisocyanate and secondary components is subjected to a purification comprising an isomer separation by distillation and/or crystallization in two or more sub-steps (a, b, . . . ), obtaining two or more methylene-diphenylene-diisocyanate-reinfractions (140-1, 140-2, . . . ) and a secondary component fraction (150), wherein the secondary component fraction (150) obtained in step ) is returned to one of the sub-steps of step ), wherein none of the methylene-diphenylene-diisocyanate-reinfractions (140-1, 140-2, . . . ) from step ) are obtained as distillation or crystallization, and/or to step .1), insofar as carried out.

The problem addressed by the present invention is to provide an antifogging coating film having excellent antifogging property, antifogging persistence, persistence of appearance, and elution resistance. The coating film according to the present invention contains a metal oxide (A) and a hydrophilic compound (B); the height of the eluate by a coating film surface elution test is 1.0 m or less; this test is carried out by placing 10 L of deionized water on the coating film, allowing the film to stand for 24 hours in a 23 C., 50% RH environment, measuring the eluate height of 20 locations selected randomly within a 10 cm.sup.2 range on the coating film surface, and determining the maximum height; and the water contact angle measured after subjecting the coating film to a moisture resistance test by exposure for 24 hours in an 85 C., 85% RH environment followed by standing for one hour in a 23 C., 50% RH environment, is less than 40. Preferably, the elution level per coating film unit volume by a coating film total elution test is 40 mg/cm.sup.3 or less, and this test is carried out by immersing the coating film in 23 C. deionized water for 24 hours, then measuring the weight of the coating film eluate recovered from the deionized water.

The present invention provides a process for preparing isocyanurate from diisocyanate, in which i) prior to the reaction the peroxide content of the diisocyanate to be used is determined, and thereafter ii) a) if the determined peroxide content is greater than 10 mmol/kg, the diisocyanate is subjected to distillative purification until the determined peroxide content is less than or equal to 10 mmol/kg, orb) if the determined peroxide content is less than or equal to 10 mmol/kg, no further action is taken, and iii) distilled diisocyanate with respect to a) and/or untreated diisocyanate with respect to b) is subsequently converted to isocyanurate.

The present invention relates to a reaction mixture including one or more polyfunctional isocyanates such that the average isocyanate functionality of the mixture is greater than 2.1, and a catalyst composition including at least one trimerization catalyst and at least one epoxide group; and curing the reaction mixture to give a cured polymer composition made up of the reaction product of isocyanates with themselves.

A polyisocyanate composition contains a modified product of xylylene diisocyanate and a modified product of pentamethylene diisocyanate, and/or a modified product of the xylylene diisocyanate and the pentamethylene diisocyanate. The ratio of the pentamethylene diisocyanate with respect to the total amount of the xylylene diisocyanate and the pentamethylene diisocyanate is 30 mol % or more and 80 mol % or less.

Functionalized isocyanate based organic aerogel/xerogel/cryogel comprising: a cross-linked porous network structure made of polyurethane and/or polyisocyanurate and/or polyurea, comprising on their pore surface before functionalization reactive groups (B) and functionalization molecules having a solubility in water <10 g/L at 20 C. chemically attached to the pore surface of the cross-linked porous network structure wherein said molecules have at least one reactive group (A) being capable of binding to said pore surface (by reaction with groups (B)) and at least one functional group (C) providing the pore surface with the desired functionalization.

The polyisocyanate cured product according to the present invention has an isocyanurate structure, which comprises at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, as a unit structure, the polyisocyanate cured product having an allophanate group, and the molar ratio of the isocyanurate group to the allophanate group (isocyanurate group/allophanate group) is 99/1 to 20/80.