摘要:
Storage-stable blocked polyisocyanates prepared by reacting one or more polyisocyanates with one or more biuretizing agents and optionally, catalysts such that in the blocked end product there are 5-45 equivalent percent of biuret groups according to formula (I) based on the sum total of all free and blocked NCO groups; optionally modifying the resulting biuret polyisocyanates with the aid of isocyanate-reactive compounds and/or catalysts, with further reaction of free NCO groups; and subsequently blocking at least 95 mol percent of the remaining free NCO groups with a blocking agent according to the formula R1R2NH, where R1 and R2 independently of one another are aliphatic or cycloaliphatic C1-C12 alkyl radicals. The blocked polyisocyanates can be used to make polyurethane polymers and coating compositions, which can be used to coat substrates.
摘要:
A process for the purification of organic isocyanates or isocyanate mixtures in which the amount of chlorine compound(s) present is reduced by mixing the isocyanate(s) or isocyanate mixtures with a gel-type or macroporous, anion-exchanging organic material having tertiary and/or quaternary amino groups. The process renders possible a purification of the isocyanates from chlorine-containing compounds which is milder than in conventional processes and is therefore particularly suitable for temperature-sensitive isocyanates.
摘要:
The present invention relates to an improved process for the preparation of polyisocyanates with a biuret structure by continuous reaction of excess amounts of organic diisocyanates having exclusively aliphatically and/or cycloaliphatically bonded isocyanate groups with organic diamines having exclusively aliphatically and/or cycloaliphatically bonded primary amino groups at elevated temperatures by 2-stage addition of the isocyanate component.
摘要:
This invention relates to coating compositions and more particularly to highly productive coating compositions that quickly harden for sanding or buffing by incorporating therein a polyisocyanate adduct mixture into the coating composition as the crosslinking material. Such coatings are particularly useful for refinishing automobiles and trucks.
摘要:
Biuret group-containing polyisocyanates are produced having an isocyanate functionality of at least 4 are prepared by reacting polyisocyanates having a functionality of at least 2.8 with water as the biuretizing agent. Most preferably water is used as the sole biuretizing agent. The preparation is useful as a curing agent in crosslinkable coating compositions. The coating composition can be used as an automotive clearcoat over a conventional pigmented basecoat, or as a basecoat or monocoat or even as a primer or sealer when a suitable amount of pigment is incorporated therein.
摘要:
Biuret group-containing polyisocyanates are produced having an isocyanate functionality of at least 4 are prepared by reacting polyisocyanates having a functionality of at least 2.8 with water as the biuretizing agent. Most preferably water is used as the sole biuretizing agent. The preparation is useful as a curing agent in crosslinkable coating compositions. The coating composition can be used as an automotive clearcoat over a conventional pigmented basecoat, or as a basecoat or monocoat or even as a primer or sealer when a suitable amount of pigment is incorporated therein.
摘要:
The present invention relates to an improved process for the continuous preparation of polyisocyanates with a biuret structure comprising the steps of continuously reacting excess amounts of organic diisocyanates having exclusively aliphatically and/or cycloaliphatically bound isocyanate groups with organic diamines having exclusively aliphatically and/or cycloaliphatically bound primary amino groups at temperatures above 170° C. and adding acid before or during the reaction.
摘要:
This invention relates to coating compositions and more particularly to highly productive coating compositions that quickly harden for sanding or buffing by incorporating therein a polyisocyanate adduct mixture into the coating composition as the crosslinking material. Such coatings are particularly useful for refinishing automobiles and trucks.
摘要:
Storage-stable Polyisocyanates based on aliphatic and/or cycloaliphatic diisocyanates including from 1 to 20% by weight of alkylamino groups of the formula R1R2N as a constituent of biuret groups, wherein R1 and R2 independently of one another are aliphatic or cycloaliphatic C1-C12 alkyl radicals, and where at least 95 mol % of the isocyanate groups are blocked with at least one blocking agent, and the polyisocyanates contain from 4.0 to 21.0% by weight of blocked and free NCO groups (calculated as NCO, molecular weight=42). The polyisocyanates are used to produce coating compositions, coatings, and coated substrates.
摘要:
The invention provides a new process for purifying organic isocyanates or isocyanate mixtures by mixing the isocyanates or isocyanate mixtures to be purified with at least one alcohol and/or thiol or a mixture of alcohols and/or thiols, heating the resultant mixture and simultaneously or subsequently degassing the mixture and/or working up the mixture by distillation and/or extraction.