Process for obtaining a hard coated article having anti-fouling properties
View Patent ↗Process for obtaining a hard coated article having anti-fouling properties, including, for example, an optical article such as an ophthalmic lens, comprising a substrate coated with a hard coating providing abrasion resistance and hardness and adhesion to the anti-fouling coating, and the article obtained from such process.
1. A process for obtaining a hard coated article having anti-fouling properties comprising:
a) applying onto the surface of a substrate a hard coating polymerizable composition further defined as:
i) a hard coating composition A comprising:
at least one silicon compound having at least one hydrolyzable group directly linked to the silicon atom and at least one epoxy group, and/or a condensation compound thereof; and
at least one cationic polymerization initiator; or
ii) a hard coating composition B comprising:
at least one epoxy compound which is neither a hydrolysis-polymerizable silicon compound nor a condensation compound thereof;
less than 5% by weight of hydrolysis-polymerizable silicone compounds and condensation compounds thereof with respect to the weight of polymerizable compounds;
less than 5% by weight of silazane compounds and condensation compounds thereof with respect to the weight of polymerizable compounds; and
at least one cationic polymerization initiator; or
iii) a hard coating composition C comprising:
at least one epoxy compound which is neither a hydrolysis-polymerizable silicon compound nor a condensation compound thereof;
at least one silicon compound having at least one hydrolyzable group directly linked to the silicon atom and at least one acryloxy or alkylacryloxy group, and/or a condensation compound thereof; and
at least one cationic polymerization initiator;
b) activating the at least one cationic polymerization initiator to partially polymerize the hard coating composition, wherein the partial polymerization is made by polymerizing the hard coating composition in an oxygen comprising gas which partially inhibits polymerization;
c) depositing onto the partially polymerized hard coating composition an anti-fouling top coat composition;
d) submitting the article resulting from the preceding step to a heating step to cure the hard coating composition and the anti-fouling top coat composition; and
e) recovering an article having a hard coat and an anti-fouling top coat deposited thereon and adhering to it.
2. The process of claim 1 , wherein the oxygen comprising gas is air.
3. The process of claim 1 , wherein the cationic polymerization initiator is a photoinitiator and the activation of b) is made by irradiation.
4. The process of claim 1 , wherein the hard coating composition comprises at least one radical polymerization initiator.
5. The process of claim 1 , wherein no activation treatment step of the surface of the applied hard coating composition is made before depositing the anti-fouling top coat composition.
6. The process of claim 1 , wherein the hard coating composition is composition B and comprises less than 5% by weight of silicon compounds, with respect to the weight of polymerizable compounds.
7. The process of claim 1 , wherein the hard coating composition is composition B and comprises no alkoxysilane compound.
8. The process of claim 1 , wherein the hard coating composition is composition B and comprises no silicon compound.
9. The process of claim 1 , wherein the hard coating composition A or the hard coating composition B comprises at least one epoxytrialkoxysilane.
10. The process of claim 9 , wherein the epoxytrialkoxysilane is γ-glycidoxypropyltrimethoxysilane.
11. The process of claim 9 , wherein the epoxytrialkoxysilane is not hydrolyzed.
12. The process of claim 9 , wherein the epoxytrialkoxysilane is under a hydrolyzed form.
13. The process of claim 1 , wherein the hard coat has a thickness ranging from 3 to 15 μm.
14. The process of claim 1 , wherein the anti-fouling top coat composition comprises one or more fluorosilane.
15. The process of claim 14 , wherein the fluorosilane comprises at least one perfluoropolyether group.
16. The process of claim 1 , wherein the anti-fouling top coat has a thickness of from 2 to 50 nm.
17. The process of claim 1 , wherein the hard coating composition is composition A and wherein composition A does not comprise any acrylic polymerizable compound.
18. The process of claim 1 , wherein the hard coating composition is composition A and comprises from 5 to 100% by weight of silicon compounds having at least one hydrolyzable group directly linked to the silicon atom and at least one epoxy group and condensation compounds thereof, relative to the total weight of polymerizable compounds and any solid fillers contained in said composition.
19. The process of claim 1 , wherein an activation treatment step of the surface of the applied hard coating composition is performed before depositing the anti-fouling top coat composition.
20. The process of claim 1 , wherein said at least one hydrolyzable group directly linked to the silicon atom comprises at least one alkoxy group, halogen group, alkenyloxy group, acyloxy group, or substituted or unsubstituted amino group.
21. The process of claim 1 , wherein the hard coating composition is composition A, wherein composition A further comprises at least one epoxy compound which is neither a hydrolysis-polymerizable silicon compound nor a condensation compound thereof.
22. The process of claim 1 , wherein the hard coating composition further comprises at least one (meth)acrylate compound which is neither a hydrolysis-polymerizable silicon compound nor a condensation compound thereof.
23. The process of claim 1 , wherein the hard coated article is further defined as comprising on the hard coat an anti-fouling top coat having a static contact angle with water of 111° or more and a thickness of 2-50 nm.