JP3007007B2 - Anti-reflective coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film for producing a plastic material having a low light reflectance.

[0002]

2. Description of the Related Art Translucent plastic materials are also used for optical filters and optical lenses, but have a refractive index in the range of 1.45 to 1.60. Even though it is transparent, it causes light reflection of about 7 to 10%.

[0003] This light reflection causes a ghost phenomenon due to a decrease and reflection of light transmittance, and also makes it difficult to see an object through the light.

As a method of removing or reducing the reflection, a 1 / 4λ film of a low refractive index, such as magnesium fluoride or silica, or a 1 / 4λ film of a high refractive index, such as titanium oxide or zirconium oxide, is used. Combined multilayer coats have been used.

For coating a small object such as an optical lens, it is a good method in terms of both film quality and productivity.
With respect to a large plate such as a full-screen panel of an RT display, the number of one-time feeding to the evaporation vessel is extremely reduced, resulting in high cost.

On the other hand, as another method, a method is known in which a solvent-soluble amorphous fluororesin is dissolved in an appropriate solvent, and a film is formed by dipping to obtain an antireflection film. Although this method is relatively easy to coat a large plate, it is irrelevant to the hardness of the resin itself and is a quarter wavelength film, that is, 100 to 20.
Since a film having a thickness of 0 nm is easily peeled off, it is impossible to use the film in a state exposed to the outside.

[0007]

According to the present invention, an overcoat layer having a thickness which does not affect the antireflection performance is further provided on an antireflection film formed of an amorphous fluororesin,
It is an object of the present invention to provide an antireflection film which significantly improves the above-mentioned problem of weak film strength, that is, abrasion resistance and abrasion resistance, and can sufficiently withstand use of a CRT display full-surface panel or the like.

According to the present invention, a plastic substrate having translucency, and a refractive index (nd) of 1.3 coated on the plastic substrate
A thickness of 100 to 20 made of an amorphous fluororesin of 6 or less
A 0 nm antireflection layer, and provided on the antireflection film.
Thickness only made of fluorine-based material having a One surface activity
Is provided with an anti-reflection film excellent in abrasion resistance and scratch resistance.

[0009]

The low refractive index of the amorphous fluororesin is due to the large content of fluorine atoms in the molecular structure. However, due to the presence of this fluorine atom, the water repellency and oil repellency of the film surface become extremely high, and even if a hard coat agent or a similar coating film is formed thereon, it is repelled, and the polka dot is formed. As a result, the film cannot be formed. However, materials having hydrophilicity, fluorophilicity, and surface-active ability, such as a low molecular weight copolymer of (meth) acrylate having a perfluoro group and ethylene glycol (meth) acrylate, are completely formed on the fluororesin surface. It shows excellent wettability and can be coated on the fluororesin surface.Better still, the slipperiness is greatly improved, and even if it is scratched with a nail or rubbed strongly with a pencil nib, it will not be scratched at all I found that it would be in a state where it would not be possible. Furthermore, it was found that water resistance and alcohol resistance can be obtained by mixing and using a (meth) acrylate homopolymer having a perfluoro group, and the present invention has been achieved.

[0010]

As the perfluoro amorphous fluorine resin for forming the film, any perfluoro amorphous fluorine resin having a ring structure in the main chain may be used. As a suitable example, the following formula (1)

[0011]

Embedded image A repeating unit of the following formula (2)

[0012]

Embedded image The repeating unit of the following formula (3)

[0013]

Embedded image Wherein R is a perfluoroalkylene group, p and q
Is a number of zero or one, at least one of the repeating units of
Seed-containing perfluorofluorine resins.

In the perfluorofluororesin, even if all of the repeating units are composed of the above cyclic repeating unit, or a part of the repeating unit is composed of the above cyclic repeating unit and the other part of the repeating unit is linear. It may consist of perfluoromonomer units.

The above-mentioned perfluoroamorphous fluororesin can be obtained by a method known per se, for example, cyclization polymerization of a perfluoroether monomer having a double bond at both terminals, and cyclization polymerization of a cyclic perfluoromonomer. It can be obtained by radical polymerization. At the time of these polymerizations, a copolymer can be obtained by allowing other perfluoro monomers to coexist.

The perfluoroether monomer having a double bond at both terminals is represented by the following formula (4): CF ₂ ＣＦCF — (— CF ₂ —) _n —O — (— CF ₂ —) _m —CF = CF ₂ (4) Perfluoroethers represented by (provided that n = 0 to 5, m = 0 to 5, and m + n = 1 to 6), for example, perfluoroallyl vinyl ether (CF
₂ = CFOCF ₂ CF = CF ₂ ), perfluorodiallyl ether (CF ₂ = CFCF ₂ OCF ₂ CF = C
F ₂ ), perfluorobutenyl vinyl ether (CF ₂
= CFOCF ₂ CF ₂ CF = CF ₂ ), perfluorobutenyl allyl vinyl ether (CF ₂ = CFCF ₂ OC
F ₂ CF ₂ CF = CF ₂ ), perfluorodibutenyl ether (CF ₂ ＣＦCFCF ₂ CF ₂ OCF ₂ CF ₂ CF)
= CF ₂ ).

Perfluoroether having a double bond at both ends
As another type of the monomer, the following formula (5) CF_Two= CFO-RO-CF = CF_Two ‥‥ (5) (where R is a perfluoroalkylene group)
Perfluoroalkylene glycol divinyl ether
For example, perfluoroe
Tylene glycol divinyl ether (CF _Two= CFOC
F_TwoCF_TwoOCF = CF_Two), Perfluorotetramethyl
Lenglycol divinyl ether (CF_Two= CFOCF
_TwoCF_TwoCF_TwoCF_TwoOCF = CF _Two)
You.

On the other hand, as the cyclic perfluoro monomer,
For example, the following equation (6)

Embedded image In the formula, R is a perfluoroalkylene group, a monomer represented by, particularly perfluoro-2,2-dimethyl-1,
3-dioxole can be mentioned.

Examples of other monomers used for copolymerization include tetrafluoroethylene, hexafluoropropylene, perfluorovinyl propyl ether, perfluoroallyl butyl ether, perfluorodivinyl ethyl ether, and perfluorovinyl allyl ether. You.

Suitable examples of amorphous fluoroplastics include, but are not limited to, cyclic ethers and perfluoro-2,2-
Copolymers with dimethyl-1,3-dioxole, copolymers of tetrafluoroethylene and cyclic perfluoroether, cyclized copolymers with perfluorovinyl allyl ether, and the like.

[0021] Specifically, "Teflon AF" manufactured by DuPont-Mitsui Fluorochemicals Co., Ltd., "CYTOP" manufactured by Asahi Glass Co., Ltd., "Fluorard FC-722" manufactured by Sumitomo 3M Limited, DuPont "Teflon AF
1600 "and the like.

As the solvent, perfluorooctane, perfluorohydrofuran, and the like have a good balance of volatilization speed, and the above resin can be dissolved at a concentration of 1 to 5% to prepare a coating solution.

In the present invention, examples of the fluorine-based material having a surface activity capable of imparting abrasion resistance and scratch resistance include a fluorinated alkyl ester having a perfluoro group and a hydrophilic group in a side chain, and a perfluoro group and a lipophilic group. And a fluorinated aliphatic polymer ester having a group in the side chain.

More specifically, as the fluorinated alkyl ester, Florad FC-43 manufactured by Sumitomo 3M Limited is used.
0, Florad FC-431, and fluorinated aliphatic polymer esters, FC-740 manufactured by Sumitomo 3M Ltd.
Is raised. However, the present invention is not limited to this material alone.

As a coating method, a dipping method that can easily form a thin film can be suitably used. The coated thin film is preferably heat-treated at a temperature of about 70 to 140 ° C. The thickness of the amorphous fluororesin is 100
It is preferable that the thickness of the fluorine material having surface active ability is 200 nm or less, preferably 100 nm or less.

As the resin substrate, although not particularly limited, polymethyl methacrylate, polycarbonate, polyallyl diglycol carbonate, polystyrene and the like can be used from the viewpoint of optical characteristics, and a substrate colored with a transparent or oil-soluble dye can be used. used. For the purpose of improving the adhesion between the fluororesin and the substrate and the adhesion, it is also possible to use a primer-coated material in the present invention in advance.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the following examples.

Preparation of Amorphous Fluororesin Coating Solution Teflon AF-1600 (manufactured by Du Pont-Mitsui Fluorochemicals Co., Ltd.) was mixed with a mixed solvent of perfluorooctane and perfluorohydrofuran having a boiling point of 102 ° C. to a concentration of 2%. A coating solution was prepared by dissolving in a certain Fluorinert FC-75 (manufactured by Sumitomo 3M Limited) (coating solution 1).

Example 1 A 2 mm-thick polymethyl methacrylate cast substrate previously coated with a silane coupling agent was pulled up at a speed of 180 m.
The film was formed at m / min. Next, using a 0.2% by weight toluene solution of "Fluorard FC-430" (manufactured by Sumitomo 3M Limited), which is a fluorinated alkyl ester, was overcoated at a pulling rate of 100 mm / min.
Further, this substrate was subjected to a heat treatment at 100 ° C. for 1 hour,
A substrate having antireflection performance was obtained. Surface reflectivity is 1.2
% (At 550 nm), the pencil hardness was 4H, and there was no scratch even when strongly rubbing with a nail.

Example 2 A 2 mm-thick polycarbonate substrate was coated with a coating solution 1 in the same manner as in Example 1, and then a fluorinated alkyl ester "Fluorard FC-43" was used.
0 "0.1% by weight, fluorinated aliphatic polymer ester" Fluorard FC-740 "(manufactured by Sumitomo 3M Ltd.)
The coating was performed at a lifting speed of 100 mm / min as a toluene solution of 0.1% by weight, a total of 0.2% by weight. Further, this substrate was subjected to a heat treatment at 120 ° C. for 1 hour to obtain a substrate having antireflection performance. Surface reflectance is 0.9%
(At 550 nm) and the pencil hardness was 3H. Furthermore, it had good water resistance and was able to withstand alcohol blow.

Comparative Example 1 The same substrate as in Example 1 was coated with the coating liquid 1 in the same manner, and heat treatment was performed at 100 ° C. for 1 hour. Although the obtained substrate had antireflection performance, the pencil hardness was 3B, and the film was easily peeled off only by lightly rubbing with a nail.

[0032]

According to the present invention, an overcoat layer having a thickness having no influence on the antireflection performance is further provided on the antireflection film formed of the amorphous fluororesin, and the film strength is reduced. In other words, the abrasion resistance and abrasion resistance are greatly improved,
It is possible to provide an antireflection film that can sufficiently withstand use of a T display full-surface panel or the like.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-19801 (JP, A) JP-A-62-148902 (JP, A) JP-A-63-212545 (JP, A) JP-A-2-212 29329 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 B05D 1/00-7/26 C08J 7/04

Claims (3)

(57) [Claims] 1. A plastic substrate having a light-transmitting property, an antireflection layer having a thickness of 100 to 200 nm and made of an amorphous fluororesin having a refractive index (nd) of 1.36 or less coated on the substrate, and the reflection A thickness of 200 nm or less consisting only of a fluorine-based material provided on
An anti-reflection film having excellent wear resistance and scratch resistance, comprising a lower coating layer. 2. A copolymer of amorphous fluorine resin is a copolymer of a cyclic ether and perfluoro-2,2-dimethyl-1,3-dioxole, tetrafluoroethylene and a cyclic perfluoroether, or tetra Fluoroethylene
2. The antireflection film according to claim 1, wherein the antireflection film is a cyclized copolymer of ethylene and perfluorovinyl allyl ether. 3. A fluorine-based material having a surface active ability,
The antireflection film according to claim 1, which is a fluorinated alkyl ester having a perfluoro group and a hydrophilic group in a side chain or a fluorinated aliphatic polymer ester having a perfluoro group and a lipophilic group in a side chain.