Coating compositions, method of forming hydrophilic films, and hydrophilic film-coated articles

• US 6,197,101 B1
• Filed: 09/11/1998
• Issued: 03/06/2001
• Est. Priority Date: 09/12/1997
• Status: Expired due to Term

• Current Assignee: Shin-Etsu Chemical Company Limited
• Original Assignee: Shin-Etsu Chemical Company Limited
• Inventors: Matsumura, Kazuyuki, Yamamoto, Akira, Yamaya, Masaaki, Furuya, Masahiro
• Primary Examiner(s): BRUNSMAN, DAVID M
• Application Number:
  US09/151,727
• Time in Patent Office: 907 Days
• Field of Search: 106/287.11, 427/515
• US Class Current: 106/287.11
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C09D 183/02 Polysilicates
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: C09D 183/08 containing silicon bound to organic groups containing atoms other than carbon, hydrogen, and oxygen

Abstract

Coating compositions comprising (a) an organosilicon compound obtained by the hydrolysis in water of a hydrolyzable mixture of specific hydrolyzable silanes or their partial hydrolyzates, (b) water, and (c) a microparticulate photooxidation catalyst, substantially reduce or eliminate the amount of organic solvent required. In addition, these coating compositions provide applied films having good weather resistance and antifouling properties, and are themselves stable even at an alkaline pH.

Claims

1. A coating composition comprising:

(a) 100 parts by weight of an organosilicon compound obtained by hydrolyzing, in water or in an organic solvent containing at least an amount of water necessary for hydrolysis, a hydrolyzable silane mixture which includes

(i) 100 parts by weight of a nitrogenous organic group-containing hydrolyzable silane of formula (1);

2. The coating composition of claim 1, wherein at least one of said nitrogenous organic groups is

wherein, R⁵, R⁶, and R⁹ to R¹³ are hydrogen atoms or monovalent hydrocarbon groups having 1 to 8 carbons, with R⁵ and R⁶, R⁹ and R¹⁰ and R¹¹, and R¹² and R¹³, respectively, being the same or different;

R is a halogen atom;

R⁷ and R⁸ are divalent hydrocarbon groups having 1 to 8 carbons atoms, with R⁷ and R⁸ being the same or different; and

p is 0 or an integer from 1 to 3.

3. The coating composition of claim 1, wherein the hydrolyzable silane of formula (1) is H₂NCH₂CH₂HNCH₂CH₂CH₂Si(OCH₃)₃ or H₂NCH₂CH₂HNCH₂CH₂CH₂Si(OCH₂CH₃)₃.

4. The composition of claim 1, wherein the hydrolyzable silane of formula (2) is Si(OCH₃)₄, Si(OCH₂CH₃)₄, CH₃Si(OCH₃)₃, or CH₃Si(OCH₂CH₃)₃.

5. The coating composition of claim 1, wherein the microparticulate photooxidation catalyst comprises particles of at least one metal oxide selected from titanium oxide, cerium oxide, and zinc oxide.

6. The coating composition of claim 1 having a pH of at least 9.

7. A method of forming a hydrophilic film, comprising the steps of

applying the coating composition of claim 1 onto a substrate to form a film, and

irradiating a surface of the film with UV-containing light so that the film surface has a contact angle with water of up to 60 degrees.

8. A hydrophilic film-coated article comprising a substrate having on a surface thereof a film of the coating composition of claim 1, which film has a contact angle with water of up to 60 degrees.

9. The coating composition of claim 1, wherein R¹ of formula (1) is —

CH₃, —

CH₂CH₃, —

CH₂CH₂CH₃, —

CH(CH₃)₂, —

CH₂CH₂CH₂CH₃, —

CH(CH₃)CH₂CH₃, —

CH₂CH(CH₃)CH₃, —

C(CH₃)₃, —

C₆H₅, or —

C₆H₁₃.

10. The coating composition of claim 1, wherein R² of formula (1) is —

OCH₃, —

OCH₂CH₃, —

OCH₂CH₂CH₃, —

OCH(CH₃)₂, —

OCH₂CH₂CH₂CH₃, —

OCH(CH₃)CH₂CH₃, —

OCH₂CH(CH₃)CH₃, —

OC(CH₃)₃, —

OCOCH₃ or —

OCOCH₂CH₃.

11. The coating composition of claim 1, wherein R² of formula (1) is —

OCH₃, or OC₂H₅.

12. The coating composition of claim 1, wherein R⁵, R⁶ and R⁹ to R¹³ of formula (2) are —

CH₃, —

CH₂CH₃, —

CH₂CH₂CH₃, —

CH(CH₃)₂, —

CH₂CH₂CH₂CH₃, —

CH(CH₃)CH₂CH₃, —

CH₂CH(CH₃)CH₃, —

C(CH₃)₃, —

C₆H₅, or —

C₆H₁₃.

13. The coating composition of claim 1, wherein R³ of formula (2) is an alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, optionally substituted with a halogen atom.

14. The coating composition of claim 1, wherein R³ of formula (2) is —

CH₃, —

CH₂CH₃, —

CH₂CH₂CH₃, —

CH(CH₃)₂, —

CH₂CH₂CH₂CH₃, —

CH(CH₃)CH₂CH₃, —

CH₂CH(CH₃)CH₃, —

C(CH₃)₃, —

C₆H₅, or —

C₆H₁₃.

15. The coating composition of claim 1, wherein R⁴ of formula (2) is —

OCH₃, —

OCH₂CH₃, —

OCH₂CH₂CH₃, —

OCH(CH₃)₂, —

OCH₂CH₂CH₂CH₃, —

OCH(CH₃)CH₂CH₃, —

OCH₂CH(CH₃)CH₃, —

OC(CH₃)₃, —

OCOCH₃ or —

OCOCH₂CH₃.

16. The coating composition of claim 1, wherein R⁴ of formula (2) is —

OCH₃ or —

OC₂H₅.

17. The coating composition of claim 1, which comprises 10 to 150 parts by weight of said hydrolyzable silane.

18. The coating composition of claim 1, wherein said hydrolyzing step (a) is performed by dropwise addition of said silane mixture to water or an organic solvent containing at least an amount of water necessary for hydrolysis.

19. The coating composition of claim 1, wherein said microparticulate photooxidation catalyst comprises particles with anatase titanium oxide.