Photocurable acrylic coating compositions having good adhesion properties to a subsequent coating and corresponding coated substrates
View Patent ↗An abrasion resistant photocurable acrylic coating composition that can provide good adhesion to subsequent coatings deposited thereon, and a hard coated article, especially an optical article such as an ophthalmic lens, comprising a substrate coated with a coating obtained from the above abrasion resistant acrylic coating composition providing good subsequent adhesion.
1. An abrasion resistant photocurable coating composition comprising:
15 to 30 parts by weight of at least one monomeric compound A having from 5 to 7 acrylate groups;
7 to 20 parts by weight of at least one monomeric or oligomeric compound A′ selected from monomers or oligomers having from 3 to 4 acrylate groups;
10 to 25 parts by weight of at least one monomeric or oligomeric compound A″ having two acrylate groups;
2 to 10 parts by weight of at least one compound B having at least two epoxy groups and that does not comprise any silicon atom bearing hydrolysable groups or hydroxyl groups;
1 to 7 parts by weight of a compound C which is a hydrolyzate of an epoxysilane having from 2 to 6 functional groups generating a silanol group under hydrolysis;
20 to 60 parts by weight of at least one non polymerisable ether compound D;
an effective amount of a cationic polymerization photo initiator; and
an effective amount of a radical polymerization initiator.
2. The composition of claim 1 , wherein the total weight of compounds A, A′ and A″ represents at least 80% of the total weight of the polymerizable compounds comprised in said coating composition.
3. The composition of claim 1 , wherein compound A has 5 acrylate groups.
4. The composition of claim 1 , wherein compound A is dipentaerythritol pentaacrylate.
5. The composition of claim 1 , wherein compound A′ is a mixture of pentaerythritol triacrylate and pentaerythritol tetra acrylate.
6. The composition of claim 1 , wherein compound A″ comprises at least one polyoxyalkyleneglycol diacrylate.
7. The composition of claim 1 , wherein the non polymerisable ether compound D is an alcohol ether compound.
8. The composition of claim 7 , wherein the alcohol ether compound comprises at least one glycol ether.
9. The composition of claim 8 , wherein the at least one glycol ether comprises a mixture of 1-methoxy-2-propanol and 2-methoxy-1-propanol.
10. The composition of claim 1 , further comprising 35 to 55 parts by weight of non polymerizable ether compound D.
11. The composition of claim 1 , wherein said epoxysilane has the following formula:
R n Y m Si(X) 4-n-m (I)
wherein:
R groups, independently, are monovalent organic groups linked to the Si atom by a carbon atom and comprising at least one epoxy function;
X groups, independently, are hydrolyzable groups;
Y is a monovalent organic group that does not contain an epoxy group and which is linked to the Si atom by a carbon atom; and
n and m are integers such as n=1 or 2 and n+m=1 or 2.
12. The composition of claim 11 , wherein the R group comprises one epoxy function.
13. The composition of claim 11 , wherein the R groups have the following formulas V and VI:
wherein:
R 2 is an alkyl group or a hydrogen atom;
a and c are integers ranging from 1 to 6; and
b represents 0, 1 or 2.
14. The composition of claim 11 , wherein in formula I, n=1, m=0 and X is a C1-C5 alkoxy group.
15. The composition of claim 14 , wherein X is —OCH 3 .
16. The composition of claim 11 , wherein the epoxysilanes comprise γ-glycidoxypropyl triethoxysilane, γ-glycidoxypropyl trimethoxysilane, 2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl) ethyltriethoxysilane, or a mixture of two or more thereof.
17. An article comprising a transparent substrate and an abrasion resistant coating composition applied thereon, resulting from the curing of an abrasion resistant photocurable coating composition of claim 1 .
18. The article of claim 17 , having a subsequent coating deposited onto and adhering on the cured abrasion resistant coating composition.
19. The article of claim 18 , wherein said subsequent coating is obtained using a sol/gel process and is comprised in an antireflective stack.
20. The article of claim 18 , wherein no pretreatment step has been performed on the cured abrasion resistant coating composition before applying said subsequent coating.
21. The article of claim 18 , wherein the subsequent coating comprises an epoxysilane hydrolyzate and a colloidal filler.
22. The article of claim 18 , wherein said subsequent coating has a thickness ranging from 10 to 200 nm.
23. The article of claim 22 , wherein said subsequent coating has a thickness ranging from 80 to 150 nm.
24. The article of claim 17 , further defined as an ophthalmic lens.