COMPOSITION FOR FORMING SILICA-BASED COATING WITH A LOW REFRACTIVE INDEX

Abstract

Compositions for forming silica-based coatings are provided that can form lower refractive-index layers of protective films on lenses of solid image-pickup devices or on optical members such as light guides.

Description

Claims

1. A composition for forming silica-based coatings with a low refractive index, comprising a siloxane polymer and an alkyl quaternary amine.

2. The composition according to claim 1, wherein the alkyl quaternary amine has a decomposition temperature of no higher than 300 degrees C.

3. The composition according to claim 1, wherein the siloxane polymer comprises a hydrolysis product and/or a partial condensate of at least one silane compound expressed by the formula (1) below: RnSiX4-n  (1)in which each R represents independently a hydrogen atom or a monovalent organic group, X represents a hydrolyzable group, n is an integer of 0 to 2 and plural Rs may be identical or different from each other.

4. A composition for forming silica-based coatings with a low refractive index, comprising a siloxane polymer, a heat-decomposable ingredient and a metal compound.

5. The composition according to claim 4, wherein the metal compound is an alkali metal compound.

6. The composition according to claim 4, wherein the heat-decomposable ingredient is an organic polymer having a decomposition temperature of no higher than 300 degrees C.

7. The composition according to claim 4, wherein the siloxane polymer comprises a hydrolysis product and/or a partial condensate of at least one silane compound expressed by the formula (1) below: RnSiX4-n  (1)in which each R represents independently a hydrogen atom or a monovalent organic group, X represents a hydrolyzable group, n is an integer of 0 to 2 and plural Rs may be identical or different from each other.

8. A composition for forming silica-based coatings with a low refractive index, comprising a siloxane polymer, a heat-decomposable ingredient, and at least one selected from base generators and acid generators.

9. The composition according to claim 8, wherein the heat-decomposable ingredient is an organic polymer having a decomposition temperature of no higher than 300 degrees C.

10. The composition according to claim 8, wherein the siloxane polymer comprises a hydrolysis product and/or a partial condensate of at least one silane compound expressed by the formula (1) below: RnSiX4-n  (1)in which each R represents independently a hydrogen atom or a monovalent organic group, X represents a hydrolyzable group, n is an integer of 0 to 2 and plural Rs may be identical or different from each other.