Coating material composition and article having coating film formed therewith

1 . A process for producing an article having a coating film with a refractive index between 1.1 and 1.35, which process comprises:

obtaining a matrix forming-material which comprises a partially hydrolyzed compound and/or a completely hydrolyzed compound having a weight average molecular weight of 2000 or more by hydrolyzing a tetraalkoxysilane represented by SiX 4 (X═OR, R is a monovalent hydrocarbon group) in the presence of water of which amount is such that a molar ratio of [H 2 O]/[OR] is in the range between 1.0 and 5.0, and in the presence of an acid catalyst,

obtaining a coating material composition by blending the matrix forming-material and at least fine hollow particles in a weight ratio of the matrix-forming material to the fine hollow particles between 95/5 and 30/70, and

applying the coating material composition on a surface of the article followed by its drying so that the coating film is formed in which the matrix forming-material forms a porous matrix.

2 . The process according to claim 1 , wherein shells of the fine hollow particles are composed of a metal oxide or silica.

3 . The process according to claim 1 , wherein a refractive index of the fine hollow particles is in the range between 1.20 and 1.40.

4 . The process according to claim 1 , wherein a particle diameter of the fine hollow particles is in the range between 5 and 2000 nm.

5 . The process according to claim 1 , wherein a refractive index of the coating film of the matrix-forming material is in the range between 1.35 and 1.50.

6 . The process according to claim 1 , wherein the matrix-forming material is hydrophilic.

7 . The process according to claim 1 , wherein a refractive index of the coating film which is obtainable by applying and drying the coating material composition on a substrate is in the range between 1.1 and 1.35.

8 . The process according to claim 1 , wherein a porosity of the coating film which is obtainable by applying and drying the coating material composition on a substrate is in the range between 10 and 95%.

9 . The process according to claim 1 , wherein a contact angle of water drop on a surface of the coating film which is obtainable by applying and drying the coating material composition on a substrate is 20° or less.

10 . A process according to claim 1 , wherein the coating composition comprises a curing catalyst.

11 . The process according to claim 1 , wherein the coating material composition further comprises colloidal silica.

12 . The process according to claim 1 , wherein the coating material composition further comprises a silane coupling agent.

13 . The process according to claim 1 , wherein the coating material composition further comprises photosemiconductor fine particles.

14 . The process according to claim 1 , wherein the coating material composition further comprises an organic porous filler.

15 . The process according to claim 1 , wherein the coating material composition further comprises an electrically conductive material.