Coating composition comprising polysiloxane-modified polyurethane for soft-feel, stain resistant coatings

Patent metadata

Field	Value
Publication number	US-11518906-B2
Application number	US-201917264041-A
Country	US
Kind code	B2
Filing date	Jul 26, 2019
Priority date	Aug 2, 2018
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

The present disclosure relates to a 2K coating composition comprising a polysiloxane-modified polyurethane and a hardener, wherein the polysiloxane-modified polyurethane obtainable by a method comprising the following steps: a) subjecting a polyol to a reaction with an isocyanate-functional silane coupling agent to obtain a silane-grafted polyol, and b) subjecting the silane-grafted polyol to a condensation reaction with a hydroxyl-functional polysiloxane, to obtain the polysiloxane-modified polyurethane. The polysiloxane-modified polyurethane can be used in a coating composition to form a coating which has smooth feel, stain resistance and easy clean properties, particularly desired in the field of e.g. consumer electronics and automotive industry.

First claim

The invention claimed is:

1. A 2K coating composition comprising a polysiloxane-modified polyurethane and a hardener, wherein the polysiloxane-modified polyurethane is obtainable by a method comprising the following steps:
a) subjecting a polyol to a reaction with an isocyanate-functional silane coupling agent to obtain a silane-grafted polyol,
b) subjecting the silane-grafted polyol to a condensation reaction with a hydroxyl-functional polysiloxane, to obtain the polysiloxane-modified polyurethane,
wherein the polysiloxane-modified polyurethane has a hydroxyl value of at least 30 mg KOH/g, and
wherein the hardener comprises at least one isocyanate.

2. The coating composition according to claim 1 , wherein the polyol is a polyester polyol.

3. The coating composition according to claim 1 , wherein the polyol has a hydroxyl value of greater than 105 mg KOH/g.

4. The coating composition according to claim 1 , wherein the isocyanate-functional silane coupling agent is selected from 3-(triethoxysilyl)propyl isocyanate, 3-(trimethoxysilyl)propyl isocyanate and mixtures thereof.

5. The coating composition according to claim 1 , wherein the hydroxyl-functional polysiloxane is dihydroxy poly(dimethylsiloxane).

6. The coating composition according to claim 1 , wherein the polysiloxane-modified polyurethane has a number average molecular weight Mn in the range of 2,000 to 5,000, as determined by gel permeation chromatography using a polystyrene standard with tetrahydrofuran as the mobile phase.

7. A method of coating a substrate, comprising applying the coating composition of claim 1 to a substrate and curing the coating composition to obtain a coated substrate.

8. A coated substrate obtainable by the method of claim 7 .

9. The coated substrate according to claim 8 , wherein the substrate is selected from the list consisting of aluminum, aluminum alloys, polycarbonate acrylonitrile butadiene styrene (PC/ABS), polycarbonate, polyacrylate, polyolefin, polyamide, polystyrene, glass, wood and stone.

Assignees

• Akzo Nobel Coatings Int Bv

Inventors

• Zhang Jintao
• Xu Jihai
• Kim Jin Hyun
• Lu Junbiao

Classifications

• C09D183/10 Primary

  Block or graft copolymers containing polysiloxane sequences (obtained by polymerising a compound having a carbon-to-carbon double bond on to a polysiloxane C09D151/08, C09D153/00) · CPC title

• C08G18/10

  Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step · CPC title

• C09D5/1656

  characterised by the film-forming substance (C09D5/1637 takes precedence) · CPC title

• C08G18/792

  formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates · CPC title

• C08G18/73

  acyclic · CPC title