Optical Laminated Film for Liquid Crystal Display Device
An optical multilayer film for a liquid crystal display comprising a hard coat layer and a low refractive index layer comprising aerogel, which layers are laminated, in this order, directly or with another intervening layer on one surface of a substrate film comprising a transparent resin, wherein the refractive index n H of the hard coat layer and the refractive index n L of the low refractive index layer satisfy the following three formulae [1], [2] and [3], n L ≦1.37 Formula [1] n H ≧1.53 Formula [2] ( n H ) 1/2 −0.2< n L <( n H ) 1/2 +0.2. Formula [3]
1 . An optical multilayer film for a liquid crystal display comprising a hard coat layer and a low refractive index layer comprising aerogel, which layers are laminated, in this order, directly or with another intervening layer on one surface of a substrate film comprising a transparent resin, wherein the refractive index n H of the hard coat layer and the refractive index n L of the low refractive index layer satisfy the following three formulae [1], [2] and [3],
n L ≦1.37 Formula [1]
n H ≧1.53 Formula [2]
( n H ) 1/2 −0.2 <n L <( n H ) 1/2 +0.2. Formula [3]
2 . The optical multilayer film for a liquid crystal display according to claim 1 , wherein the low refractive index layer is a cured film formed from a coating material composition comprising:
(i) fine hollow particles having a shell comprised of a metal oxide,
(ii) at least one hydrolysis product selected from:
(ii-1) a hydrolysis product (A) obtained by hydrolysis of a hydrolyzable organosilane represented by the following general formula (1):
SiX 4
where each X individually represents a hydrolyzable group, and
(ii-2) a copolymerization-hydrolysis product (B) obtained by hydrolysis and copolymerization of a hydrolyzable organosilane represented by the formula (1) with a hydrolyzable organosilane having a fluorine-substituted alkyl group or groups; and
(iii) a hydrolyzable organosilane (C) having water-repellent groups in its straight-chain structure, and having at least two silicon atoms in the molecule, each of which is bonded with an alkoxy group or alkoxy groups.
3 . The optical multilayer film for a liquid crystal display according to claim 2 , wherein the water-repellent groups of the hydrolyzable organosilane (C) are represented by the following general formula (2) or (3):
General Formula (2):
where each R 1 and R 2 individually represents an alkyl group, and n is an integer of 2 to 200,
—[—CF 2 —] m —, General formula (3)
where m is an integer of 2 to 20.
4 . The optical multilayer film for a liquid crystal display according to claim 1 , wherein the low refractive index layer is a cured film formed from a coating material composition comprising:
(i) fine hollow particles having a shell comprised of a metal oxide,
(ii) at least one hydrolysis product selected from.
(ii-1) a hydrolysis product (A) obtained by hydrolysis of a hydrolyzable organosilane represented by the following general formula (1):
SiX 4
where each X individually represents a hydrolyzable group, and
(ii-2) a copolymerization-hydrolysis product (B) obtained by hydrolysis and copolymerization of a hydrolyzable organosilane represented by the formula (1) with a hydrolyzable organosilane having a fluorine-substituted alkyl group or groups; and
(iii) a dimethyl-type silicone diol (D) represented by the following general formula (4);
where p is a positive integer.
5 . The optical multilayer film for a liquid crystal display according to claim 4 , wherein the positive integer p in the formula (4) is in the range of 20 to 100.
6 . The optical multilayer film for a liquid crystal display according to claim 1 , wherein the low refractive index layer is a cured film formed from a coating material composition comprising:
(i) a re-hydrolyzed product obtained by subjecting a mixture comprising fine hollow particles having a shell comprised of a metal oxide, and a hydrolysis product (A) obtained by hydrolysis of a hydrolyzable organosilane represented by the following general formula (1):
SiX 4
where each X individually represents a hydrolyzable group, to a hydrolysis treatment whereby the hydrolysis product (A) is re-hydrolyzed; and
(ii) a copolymerization-hydrolysis product (B) obtained by hydrolysis and copolymerization of a hydrolyzable organosilane represented by the formula (1) with a hydrolyzable organosilane having a fluorine-substituted alkyl group or groups.
7 . The optical multilayer film for a liquid crystal display according to claim 2 , wherein the coating material composition for forming the cured film further comprises:
(a) porous particles, which are prepared by subjecting a mixture comprising an alkyl silicate, a solvent, water and a catalyst for hydrolysis and polymerization, to a hydrolysis-polymerization whereby the alkyl silicate is hydrolyzed and polymerized; and then removing the solvent by drying the hydrolysis-polymerization product; and/or
(b) porous particles having a cohesion average particle diameter in the range of 10 nm to 100 nm, which are prepared by subjecting a mixture comprising an alkyl silicate, a solvent, water and a catalyst for hydrolysis and polymerization, to a hydrolysis-polymerization whereby the alkyl silicate is hydrolyzed and polymerized; terminating polymerization before the polymerization mixture is gelled to give a stabilized organosilica sol; and then removing the solvent by drying the organosilica sol.
8 . The optical multilayer film for a liquid crystal display according to claim 2 , wherein the hydrolysis product (A) comprises a partially or completely hydrolyzed product having a weight average molecular weight of at least 2,000 which is prepared by hydrolyzing the hydrolyzable organosilane of the formula (1) in the presence of water in amount such that the molar ratio of [H 2 O]/[X] is in the range of 1.0 to 5.0 and further in the presence of an acid catalyst.
9 . The optical multilayer film for a liquid crystal display according to claim 2 , wherein the refractive index n H of the hard coat layer and the refractive index n L of the low refractive index layer satisfy the following three formulae [4], [5] and [6],
n L ≦1.25 Formula [4]
n H ≧1.55 Formula [5]
( n H ) 1/2 −0.15 <n L ,<( n H ) 1/2 +0.15. Formula [6]
10 . The optical multilayer film for a liquid crystal display according to claim 2 , which has a reflectivity of not larger than 0.7% at a wavelength of 550 nm and a reflectivity of not larger than 1.5% at a wavelength in the range of 430 nm to 700 nm.
11 . The optical multilayer film for a liquid crystal display according to claim 2 , wherein the substrate film has a die line with a depth or height of not larger than 0.1 μm.
12 . The optical multilayer film for a liquid crystal display according to claim 2 , wherein the transparent resin is selected from the group consisting of a polymer resin having an alicyclic structure, a cellulose resin and a polyester resin.
13 . The optical multilayer film for a liquid crystal display according to claim 2 , wherein the transparent resin is a polymer resin having an alicyclic structure.