Weather-resistant hard coat composition for metal, cured product, and coated metal substrate

Patent metadata

Field	Value
Publication number	US-2022017777-A1
Application number	US-201917295741-A
Country	US
Kind code	A1
Filing date	Nov 20, 2019
Priority date	Nov 21, 2018
Publication date	Jan 20, 2022
Grant date	—

Abstract

The purpose of the present invention is to provide a weather-resistant hard coat composition for a metal, the composition being capable of efficiently forming a coating film excelling in weather resistance, scratch resistance, and flexibility. The present invention provides: a weather-resistant hard coat composition for a metal, the composition containing a polyorganosilsesquioxane having a constituent unit represented by Formula (1); a cured product thereof; and a coated metal substrate having a metal substrate and a coating film formed on at least one surface of the metal substrate. The coating film is a layer of a cured product of the weather-resistant hard coat composition for a metal. [In Formula (1), R1 represents a group containing an active energy ray-curable functional group.][R1SiO3/2]  (1)

First claim

1 . A weather-resistant hard coat composition for a metal, the composition comprising a polyorganosilsesquioxane having a constituent unit represented by Formula (1):
[R 1 SiO 3/2 ]  (1)
where R 1 represents a group containing an active energy ray-curable functional group.

2 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein the polyorganosilsesquioxane further comprises:
a constituent unit represented by Formula (I):
[R a SiO 3/2 ]  (I)

where R a represents a group containing an active energy ray-curable functional group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a hydrogen atom; and
a constituent unit represented by Formula (II):
[R b SiO 2/2 (OR c )]  (II)

where R b represents a group containing an active energy ray-curable functional group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a hydrogen atom, and R c represents a hydrogen atom or an alkyl group having from 1 to 4 carbons; and
wherein a molar ratio [(constituent unit represented by Formula (I))/(constituent unit represented by Formula (II))] of the constituent unit represented by Formula (I) to the constituent unit represented by Formula (II) is from 5 to 500.

3 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein a number average molecular weight of the polyorganosilsesquioxane is from 1000 to 50000.

4 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein the polyorganosilsesquioxane further comprises a constituent unit represented by Formula (4):
[R 1 SiO 2/2 (OR c )]  (4)
where R 1 is the same as in Formula (1), and R c is the same as in Formula (II), and wherein a ratio of the constituent unit represented by Formula (1) and the constituent unit represented by Formula (4) with respect to a total amount (100 mol %) of siloxane constituent units is from 55 to 100 mol %.

5 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein a molecular weight dispersity (weight average molecular weight/number average molecular weight) of the polyorganosilsesquioxane is from 1.0 to 4.0.

6 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein the polyorganosilsesquioxane further comprises a constituent unit represented by Formula (2):
[R 2 SiO 3/2 ]  (2)
where R 2 represents a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkenyl group.

7 . The weather-resistant hard coat composition for a metal according to claim 6 , wherein R 2 represents a substituted or unsubstituted aryl group.

8 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein the active energy ray-curable functional group is an epoxy group.

9 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein R 1 is:
a group represented by Formula (1a):

where R 1a represents a linear or branched alkylene group;

a group represented by Formula (1b):

where R 1b represents a linear or branched alkylene group;

a group represented by Formula (1c):

where R 1c represents a linear or branched alkylene group; or

a group represented by Formula (1d):

where R 1d represents a linear or branched alkylene group.

10 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein the active energy ray-curable functional group is a (meth)acryloxy group.

11 . The weather-resistant hard coat composition for a metal according to claim 1 , further comprising a photocuring catalyst.

12 . The weather-resistant hard coat composition for a metal according to claim 11 , wherein the photocuring catalyst is a photocationic polymerization initiator.

13 . The weather-resistant hard coat composition for a metal according to according to claim 11 , wherein the photocuring catalyst is a photoradical polymerization initiator.

14 . The weather-resistant hard coat composition for a metal according to claim 1 , further comprising a compound having one or more (meth)acryloxy group(s) per molecule.

15 . The weather-resistant hard coat composition for a metal according to claim 1 , further comprising at least one type selected from the group consisting of ultraviolet absorbers and antioxidants.

16 . The weather-resistant hard coat composition for a metal according to claim 1 , further comprising a compound having one or more thermally-polymerizable functional group(s) and one or more photopolymerizable functional group(s) per molecule.

17 . The weather-resistant hard coat composition for a metal according to claim 1 , further comprising a fluorine-containing photopolymerizable resin.

18 . The weather-resistant hard coat composition for a metal according to claim 1 , wherein the composition is a clear hard coat paint.

19 . A cured product of the weather-resistant hard coat composition for a metal described in claim 1 .

20 . A coated metal substrate comprising a metal substrate and a coating film formed on at least one surface of the metal substrate, wherein the coating film is a layer of the cured product described in claim 19 .

21 . The coated metal substrate according to claim 20 , wherein a thickness of the coating film is from 1 to 200 μm.

22 . A weather-resistant hard coat composition for a metal substrate satisfying a pencil hardness as defined below of a cured product obtained by curing a composition under curing conditions set forth below being not less than H, a color difference (ΔE) as defined below being less than 20, and a glossiness retention rate as defined below being not less than 15%:
curing conditions
pre-baking: 5 minutes at 150° C.
UV radiation: radiation dosage: 400 mJ/cm 2 , radiation intensity: 260 mW/cm 2
aging: at 120° C. for 0.5 hours
pencil hardness
measured in accordance with JIS K5600-5-4 (750 g load)
color difference (ΔE)
determined from an initial hue value and a hue of a sample after 3000 hours of radiation in a high luminance xenon weatherometer test under the following conditions:
glossiness retention rate (%)
calculated from the following equation by measuring a glossiness before radiation and a glossiness after radiation for 3000 hours in a high luminance xenon weatherometer test under the following conditions:
Glossiness Retention Rate (%)=(Glossiness after radiation for 3000 hours)/(Glossiness before radiation)×100

high luminance

Assignees

• Daicel Corp

Inventors

• Shimizu Kunio
• Takahashi Hiroshi
• Shibamoto Akihiro

Classifications

• Y10T428/31

  Surface property or characteristic of web, sheet or block · CPC title

• Y10T428/31663

  As siloxane, silicone or silane · CPC title

• Y10T428/26

  Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension · CPC title

• C09D151/085

  on to polysiloxanes · CPC title

• C08F290/068

  Polysiloxanes · CPC title