Uv-curable coating composition

Patent metadata

Field	Value
Publication number	US-2016017169-A1
Application number	US-201414763549-A
Country	US
Kind code	A1
Filing date	Jan 30, 2014
Priority date	Feb 1, 2013
Publication date	Jan 21, 2016
Grant date	—

Abstract

The present invention relates to a coating composition comprising:
a) one or more aliphatic polymer precursors selected from components A.1 and optionally A.2:
A.1) aliphatic oligomers containing urethane or ester bonds and having at least two acrylate functions per molecule, or mixtures of said oligomers, and A.2) aliphatic reactive diluents having at least two acrylate groups per molecule, or mixtures of said reactive diluents,
b) optionally one or more finely divided inorganic compounds, c) an organic UV absorber, d) optionally a free radical scavenger from the HALS class, e) optionally one or more levelling additives, f) optionally one or more solvents, and g) a photoinitiator.

It further relates to a process for the coating of a substrate, to the coated substrates obtainable in this way, and to the use of the coated substrates.
UV absorbers C) are those of formulae (Ia) and (Ib):

and
B—X—O—C(═O)—C(R)═CH 2   (formula Ib)

where
B is:

First claim

1 .- 16 . (canceled)

17 . A coating composition comprising:
A) one or more aliphatic polymer precursors selected from components A.1 and optionally A.2:
A.1) aliphatic oligomers containing urethane or ester bonds and having at least two acrylate functions per molecule, or mixtures of said oligomers, and
A.2) aliphatic reactive diluents having at least two acrylate groups per molecule, or mixtures of said reactive diluents,
B) optionally one or more finely divided inorganic compounds, C) an organic UV absorber, D) a non-incorporable free radical scavenger from the HALS class, E) optionally one or more levelling additives, F) optionally one or more solvents, and G) a photoinitiator, the organic UV absorber C) being an absorber of general formula (Ia):

where
R 1 is hydrogen or a methyl radical,
Q is a linear or branched alkylene having preferably 1 to 10 . . . .
T is a nucleus of the aliphatic and cycloaliphatic polyisocyanates T(NCO) m which have cyclic isocyanurate, uretdione, iminooxadiazinedione or oxadiazinetrione structures, as well as branched biuret structures in the case of cycloaliphatic polyisocyanates,
m corresponds to the original average NCO functionality of the polyisocyanate used and is equal to or greater than 2,
A is an optionally substituted, linear or branched alkylene having preferably 1 to 20 carbon atoms, it being possible for the carbon chain to be interrupted by oxygen, carboxyl, nitrogen, sulfur, phosphorus and/or silicon,
and
x represents the average molar proportion of the bound UV absorber radical and is less than m, or the organic UV absorber C) being an absorber of general formula (Ib):
A-X—O—C(═O)—C(R)═CH 2   (Ib)

where
A is:

Y 1 and Y 2 independently of one another are substituents of the general formula

r is 0 or 1, preferably 1,
R 1 , R 2 , R 3 independently of one another are H, OH, C 1-20 -alkyl, C 4-12 -cycloalkyl, C 2-20 -alkenyl, C 1-20 -alkoxy, C 4-12 -cycloalkoxy, C 2-20 -alkenyloxy, C 7-20 -aralkyl, halogen, —C≡N, C 1-5 -halogenoalkyl, —SO 2 R′, —SO 3 H, —SO 3 M (M=alkali metal), —COOR′, —CONHR′, —CONR′R″, —OCOOR′, —OCOR′, —OCONHR′, (meth)acrylamino, (meth)acryloxy, C 6-12 -aryl optionally substituted by C 1-12 -alkyl, C 1-12 -alkoxy, CN and/or halogen, or C 3-12 -heteroaryl optionally substituted by C 1-12 -alkyl, C 1-12 -alkoxy, CN and/or halogen,
M is an alkali metal cation,
R′ and R″ are H, C 1-20 -alkyl, C 4-12 -cycloalkyl, C 6-12 -aryl optionally substituted by C 1-12 -alkyl, C 1-12 -alkoxy, CN and/or halogen, or C 3-12 -heteroaryl optionally substituted by C 1-12 -alkyl, C 1-12 -alkoxy, CN and/or halogen,
X is branched or unbranched C 1-20 -alkyl, and
R is H or CH 3 .

18 . The coating composition according to claim 17 , wherein X in formula (Ib) for the UV absorber C) is CH(CH 3 ) and T in formula (Ia) is an isocyanurate based on hexamethylene diisocyanate (HDI).

19 . The coating composition according to claim 17 , wherein r in the substituents Y 1 and Y 2 in formula (Ib) for the UV absorber C) is in each case 1 and Q in formula (la) is CH 2 —CH 2 .

20 . The coating composition according to claim 17 , wherein the radicals R 1 , R 2 and R 3 in the substituents Y 1 and Y 2 in formula (I) for the UV absorber C) are in each case H and A in formula (Ia) is C(CH 3 )—CO—O—CH 2 —CR 4 R 5 —CH 2 , R 4 and R 5 independently of one another being alkyl having 1 to 6 carbon atoms.

21 . The coating composition according to claim 17 , wherein component A.1 comprises an unsaturated aliphatic urethane acrylate.

22 . The Coating composition according to claim 17 , wherein component C is a UV absorber of formula (Ia) with the following groups:

T is a urethane acrylate based on HDI (hexamethylene diisocyanate) isocyanurate, partially reacted with hydroxyethyl acrylate,
Q is —CH 2 —CH 2 — and
R is hydrogen,
or a UV absorber of formula (Ia) with the following groups:

T is a urethane acrylate based on HDI (hexamethylene diisocyanate) isocyanurate, partially reacted with hydroxyethyl acrylate.
Q is —CH 2 —CH 2 — and
R is hydrogen.

23 . The coating composition according to claim 17 , wherein component C is a UV absorber of general formula (Ib):
A-X—O—C(═O)—C(R)═CH 2   (Ib)
where A is:

Y 1 and Y 2 independently of one another are substituents of the general formula

r is 0 or 1, preferably 1,
R 1 , R 2 , R 3 independently of one another are H, OH, C 1-20 -alkyl, C 4-12 -cycloalkyl, C 2-20 -alkenyl, C 1-20 -alkoxy, C 4-12 -cycloalkoxy, C 2-20 -alkenyloxy, C 7-20 -aralkyl, halogen, —C≡N, C 1-5 -halogenoalkyl, —SO 2 R′, —SO 3 H, —SO 3 M (M=alkali metal), —COOR′, —CONHR′, —CONR′R″, —OCOOR′, —OCOR′, —OCONHR′, (meth)acrylamino, (meth)acryloxy, C 6-12 -aryl optionally substituted by C 1-12 -alkyl, C 1-12 -alkoxy, CN and/or halogen, or C 3-12 -heteroaryl optionally substituted by C 1-12 -alkyl, C 1-12 -alkoxy, CN and/or halogen,
M is an alkali metal cation,
R′ and R″ are H, C 1-20 -alkyl, C 4-12 -cycloalkyl, C 6-12 -aryl optionally substituted by C 1-12 -alkyl, C 1-12 -alkoxy, CN and/or halogen, or C 3-12 -heteroaryl optionally substituted by C 1-12 -alkyl, C 1-12 -alkoxy, CN and/or halogen,
X is branched or unbranched C 1-20 -alkyl, and
R is H or CH 3 .

24 . The coating composition according to claim 17 , comprising a non-incorporable free radical scavenger from the HALS class.

25 . The coating composition according to claim 24 , wherein the free radical scavenger from the HALS class is a piperidine derivative having the general structure of formula (IV):

where
Y=H or CH 3 ,
R 14 =Z—R 15 —Z—R 16 ,

Z=a divalent functional group,
R 15 =a divalent organic radical,
and
R 16 is H or C 1 -C 20 -alkyl.

26 . A process for the coating of a substrate, comprising the following steps:
applying the coating composition according to claim 17 to a substrate; curing of the applied coating composition by irradiation with UV light in a dose of at least 2 J/cm 2 .

27 . A coated substrate comprising a substrate and a coating arranged on or above the substrate, wherein the coating comprises a coating composition according to claim 17 .

28 . The coated substrate according to claim 27 , wherein the substrate is a polycarbonate substrate, a polymethyl methacrylate substrate, a polystyrene substrate or a polyolefin substrate.

29 . A coated substrate comprising a substrate and a coating arranged on or above the substrate, w

Assignees

• Bayer Materialscience Ag

Inventors

• Kostromine Serguei
• Kühn Frauke

Classifications

• B05D3/067

  Curing or cross-linking the coating · CPC title

• C09D133/14 Primary

  of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen · CPC title

• C08K5/005

  Stabilisers against oxidation, heat, light, ozone · CPC title

• C08K5/0025

  Crosslinking or vulcanising agents; including accelerators · CPC title

• C09D175/16

  having terminal carbon-to-carbon unsaturated bonds · CPC title