Silica-free UV-absorbing abrasion resistant coatings

• US 6,106,605 A
• Filed: 07/23/1997
• Issued: 08/22/2000
• Est. Priority Date: 10/02/1990
• Status: Expired due to Term

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Basil, John Darwin, Hunia, Robert Michael, Lin, Chia-Cheng
• Primary Examiner(s): Moore, Margaret G.
• Application Number:
  US08/898,754
• Time in Patent Office: 1,126 Days
• Field of Search: 106/287.12, 106/287.14
• US Class Current: 106/287.12
• CPC Class Codes: C08J 2369/00 Characterised by the use of polycarbonates; Derivatives of polycarbonates
• CPC Class Codes: C08J 2433/06 of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical
• CPC Class Codes: C08J 2483/04 Polysiloxanes
• CPC Class Codes: C08J 7/042 with two or more layers, where at least one layer of a composition contains a polymer binder
• CPC Class Codes: C08J 7/043 Improving the adhesiveness of the coatings per se, e.g. forming primers adhesives in the form of films or foils characterised by the primer layers between the polymer carriers and the adhesives C09J7/50
• CPC Class Codes: C08J 7/046 Forming abrasion-resistant coatings; Forming surface-hardening coatings
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C09D 183/06 containing silicon bound to oxygen-containing groups C09D183/12 takes precedence
• CPC Class Codes: C09D 183/08 containing silicon bound to organic groups containing atoms other than carbon, hydrogen, and oxygen
• CPC Class Codes: Y10T 428/31507 Of polycarbonate
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

A silica-free, abrasion resistant and ultraviolet radiation resistant coating is disclosed comprising an organic UV absorbing compound such as hydroxybenzophenone in an inorganic oxide matrix formed by the hydrolysis and condensation of an organo alkoxysilane and a silicon other metal alkoxide.

Claims

1. A silica-free coating composition for protecting a substrate from ultraviolet radiation and abrasion comprising a reaction product of:

a. a partially hydrolyzed alkoxide selected from compounds of the general formula R_x Si(OR'"'"')_4-x wherein R is an alkyl radical, and x is an integer and is less than 4; and

b. an organic compound which absorbs ultraviolet radiation selected from the group consisting of hydroxybenzophenone and hydroxybenzotriazole, where the terminal hydroxyl group is available for reacting with silanol groups, and

wherein R'"'"' of said partially hydrolyzed alkoxide is an alkyl radical selected from the group consisting of methyl, ethyl, propyl and butyl radicals.

2. A composition according to claim 1, wherein said partially hydrolyzed alkoxide is selected from the group consisting of partially hydrolyzed methyltrimethoxysilane, partially hydrolyzed dimethyldiethoxysilane and mixtures thereof.

3. A composition according to claim 2, wherein said coating further comprises 3-glycidoxypropyltrimethoxysilane.

4. A composition according to claim 3, wherein said coating further comprises an organic polymer selected from the group consisting of polyvinyl acetate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone and copolymers thereof.

5. A composition according to claim 4, wherein the substrate is polycarbonate.

26. A composition according to claim 1, wherein the substrate is coated substrate where the coating is an acrylic primer solution.

30. A composition according to claim 1, wherein said hydroxybenzophenone is (2,4, dihydroxyphenyl)phenylmethanone.

6. A silica-free coating composition for protecting a substrate from ultraviolet radiation and abrasion comprising a hydrolytic polycondensation reaction product of:

a. a partially hydrolyzed alkoxide selected from compounds of the general formula R_x Si(OR'"'"')_4-x wherein R is an alkyl radical, and x is an integer and is less than 4;

b. an organoalkoxysilane selected from compounds of the general formula R_y Si(OR'"'"')_4-y wherein R is an organic radical, and y is an integer and is at least one; and

c. an organic compound which absorbs ultraviolet radiation selected from the group consisting of hydroxybenzophenone and hydroxybenzotriazole, where the terminal hydroxyl group is available for reacting with silanol groups, and

wherein R'"'"' of said partially hydrolyzed alkoxide and R'"'"' of said organoalkoxysilane are each independently an alkyl radical selected from the group consisting of methyl, ethyl, propyl and butyl radicals.

7. A composition according to claim 6, wherein said partially hydrolyzed alkoxide is selected from the group consisting of partially hydrolyzed methyltrimethoxysilane, partially hydrolyzed dimethyldiethoxysilane, and mixtures thereof.

8. A composition according to claim 6, wherein said organoalkoxysilane is an organotrimethoxysilane wherein R of said organotrimethoxysilane is selected from the group consisting of vinyl, phenyl, methoxyethyl, 3-glycidoxypropyl and 3-methacryloxypropyl.

9. A composition according to claim 6, wherein said ultraviolet radiation absorbing organic compound is hydroxybenzophenone.

10. A composition according to claim 6, wherein said ultraviolet radiation absorbing compound is 2,4-hydroxybenzophenone.

11. A composition according to claim 6, wherein said composition further comprises an organic polymer selected from the group consisting of polyvinyl acetate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone and copolymers thereof.

12. A composition according to claim 6, wherein said substrate is polycarbonate.

27. A composition according to claim 6, wherein alkoxide is alkyltrialkoxysilane present in an amount of 28 to 48 percent, the organic alkoxysilane is present in an amount of 1 to 20 percent, and the organic compound is present in an amount up to 1 percent and the composition further contains:

20 to 40 percent water;

1 to 3 percent acid, and

optionally, up to 1 percent organic polymer selected from the group consisting of;

polyethylene oxide, and polyvinylpyrrolidone;

up to 0.1 percent curing catalysts selected from the group consisting of;

organic and inorganic acetates, amines, carboxylates, hydroxides and basic salts,

up to 0.1 percent of sodium acetate, and tetramethyl ammonium hydroxide.

31. A composition according to claim 6, wherein said hydroxybenzophenone is (2,4, dihydroxyphenyl)phenylmethanone.

13. A silica-free optically transparent coating composition for protecting a substrate from ultraviolet radiation consisting essentially of:

a. a partially hydrolyzed alkoxide of the general formula R_x Si(OR'"'"')_4-x wherein R is an alkyl radical, R'"'"' is an alkyl radical, and x is an integer and is less than 4;

b. an organoalkoxysilane of the general formula R_y Si(OR'"'"')_4-y wherein R is an organic radical, R'"'"' is an alkyl radical and y is an integer and is at least one;

wherein R'"'"' of said partially hydrolyzed alkoxide and R'"'"' of said organoalkoxysilane are each independently an alkyl radical selected from the group consisting of methyl, ethyl, propyl and butyl radicals; and

c. an organic compound which absorbs ultraviolet radiation containing hydrophilic extensions with terminal hydroxyl groups capable of reacting with silanol groups.

14. A composition according to claim 13, wherein said alkoxide has the general formula R_x Si(OR'"'"')_4-x and R'"'"' is selected from the group consisting of methyl, ethyl, propyl and butyl.

15. A composition according to claim 14, wherein said organoalkoxysilane is a trimethoxysilane and R of said organotrimethoxysilane is selected from the group consisting of vinyl, phenyl, methoxyethyl, 3-glycidoxy, 3-glycidoxypropyl and 3-methacryloxypropyl.

16. A composition according to claim 15, wherein said alkoxide comprises methyl trimethoxysilane.

17. A composition according to claim 15, wherein said organoalkoxysilane comprises 3-glycidoxypropyl trimethoxysilane.

18. A composition according to claim 13, wherein said organic compound comprises a compound selected from the group consisting of hydroxybenzotriazole and hydroxybenzophenone.

19. A composition according to claim 18 to which is added an organic polymer selected from the group consisting of polyvinyl acetate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone and copolymers thereof.

28. A composition according to claim 15, wherein the trialkoxysilane from 1 to 20 percent by weight of the alkoxide portion of the composition.

29. A composition according to claim 19, wherein the polyvinylpyrrolidone copolymer is polyvinylpyrrolidone/polyvinylacetate copolymer.

32. A composition according to claim 18, wherein said hydroxybenzophenone is (2,4, dihydroxyphenyl)phenylmethanone.

20. A method of preparing an optically transparent ultraviolet resistant coating composition comprising the steps of:

a. at least partially hydrolyzing an alkoxide of the general formula R_x Si(OR'"'"')_4-x wherein R is an alkyl radical, R'"'"' is an alkyl radical, and x is an integer and is less than 4;

b. adding an organoalkoxysilane of the general formula R_y Si(OR'"'"')_4-x wherein R is an organic radical, R'"'"' is an alkyl radical and y is an integer and is at least one;

wherein R'"'"' of said partially hydrolyzed alkoxide and R'"'"' of said organoalkoxysilane are each independently an alkyl radical selected from the group consisting of methyl, ethyl, propyl and butyl radicals; and

c. adding an organic compound which absorbs ultraviolet radiation containing hydrophilic extensions with terminal hydroxyl groups capable of reacting with silanol groups.

21. A method according to claim 20, wherein said alkoxide has the general formula R_x Si(OR'"'"')_4-x and R'"'"' is selected from the group consisting of methyl, ethyl, propyl and butyl.

22. A method according to claim 21, wherein said organoalkoxysilane is a trimethoxysilane and R is selected from the group consisting of vinyl, phenyl, methoxyethyl, 3-glycidoxy, 3-glycidoxypropyl and 3-methacryloxypropyl.

23. A method according to claim 22, wherein said alkoxide comprises methyl trimethoxysilane.

24. A method according to claim 23, wherein said organoalkoxysilane comprises 3-glycidoxypropyl trimethoxysilane.

25. A method according to claim 20, wherein said hydroxy containing organic compound comprises 2,4-hydroxybenzophenone.

33. The method according to claim 25, wherein said hydroxybenzophenone is (2,4, dihydroxyphenyl)phenylmethanone.