JPS61293270A - Glare protection film-forming composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. which can form a glare protection film having excellent adhesion, antistatic properties and resistance to solvents and marring on the surface of glass and synthetic resin sheets, consisting of an alcoholic silica sol and a surface-curved resin. CONSTITUTION:A hydrolyzable silicon compd. (e.g. tetramethyl silicate) is hydrolyzed in the presence or absence of an acid catalyst (e.g. HCl) in a alcoholic solvent (e.g. methanol) at room temp. for 1-48 hr to obtain an alcoholic silica sol (A). 2-5pts.wt. ultraviolet-curable or thermosetting surface-curved resin is blended with 1pt.wt. (on a silica basis) component A to obtain a glare protection film-forming compsn. having a nonvolatile residue content 5-15wt.%. The compsn. is sprayed through a nozzle having a bore of 0.4-0.8mm on the surface of glass or a synthetic resin sheet and heated at 30-60 deg.C for 30-60min. or irradiated with ultraviolet light to cure it, thus forming a glare protection film having excellent glare protection characteristics and resolution characteristics.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides anti-glare properties applicable to glass surfaces and transparent synthetic resin plate surfaces with excellent adhesion, scratch resistance, solvent resistance and antistatic properties. The present invention relates to a film-forming composition.

(Background of the invention) In recent years, with the progress of office automation (OA), computers have been introduced into companies and workplaces. The problem of visual impairment of operators who carry out this work has been attracting attention. In order to prevent this operator's visual impairment, the current situation is to manage, regulate, and shorten VDT working hours to minimize this impairment as much as possible. Visual impairment is caused by harmful ultraviolet rays emitted by the display device (cathode ray tube) and external light reflected from the surface of the display device (cathode ray tube), and the reflected light tiring the operator's eyes. This is said to be the cause of the problem, and urgent action is needed.

In addition to OA equipment, for example, as seen in home television receivers, external light is uniformly reflected on the cathode ray tube surface, so bright objects such as electric lights and windows are reflected on the cathode ray tube surface, making it difficult to see the screen. , which also has a bad effect on the eyes.

(Prior Art) In an attempt to solve the above-mentioned problems, a surface having fine irregularities is formed on the reflective surface.

There is a technology that suppresses regular reflection and diffuses reflection to create anti-glare. Such surface treatment may be applied directly to the surface of the cathode ray tube, or may be applied to the front surface of a synthetic resin filter placed in front of the cathode ray tube.

Various methods can be considered for antiglare treatment on the surface of a synthetic resin.

For example, when injection molding a synthetic resin, anti-glare treatment is applied to the surface of the synthetic resin molded product using a mold whose surface has been sandblasted, and when performing casting molding,
The surface of the glass plate to be used as the mold is roughened by sandblasting or corroded with hydrofluoric acid, and cast molding is performed between the roughened glass plate, or by mixing fine particles into synthetic resin paint and painting it. Although there are methods for anti-glare treatment of synthetic resin surfaces, none of these anti-glare treatments are very effective and are economically expensive.

More specifically, if we look at recently proposed anti-glare treatment technologies of this type, 1, for example, Patent Publication No. 4456/1986.
No. 4 discloses an anti-glare coating composition in which an inorganic substance having a specific gravity of 2.5 or less and consisting mainly of Sin, Al, and Ol is mixed in an ultraviolet curable coating in a range of 2% by weight to 30% by weight. In this case, it is necessary to make the particle size of the inorganic material fine and to uniformly disperse it in the ultraviolet curable paint, and sufficient control is required to obtain a dense and uniform anti-glare film. Further, since the film is formed by dispersing inorganic fine particles in the ultraviolet curable paint film, antistatic properties cannot be expected.

On the other hand, according to Utility Model Application Publication No. 50-26277, a solution of silicon tetrachloride mixed with an appropriate amount of alcohol or ester solvent is sprayed onto the front surface of a cathode ray tube glass bulb, and then heated and cured. By this,
A technique has been disclosed in which an uneven coating made of fine silica particles is formed on the front surface of a cathode ray tube glass bulb to provide an anti-glare effect.

According to this technique, a cathode ray tube glass bulb having a uniform and effective anti-glare function can be easily obtained. However, when this method is applied to synthetic resin plates, although an excellent anti-glare effect can be obtained, the adhesiveness is poor and it easily peels off in the cellophane tape test, making it impossible to put it to practical use.

In contrast to these prior art techniques, the present inventors themselves.

By spraying the condensation reaction product of a silyl group-containing vinyl polymer and polysiloxane onto the resin surface, a finely uneven coating is formed on the surface of the synthetic resin plate and cured by heating, further improving resolution and surface properties in some cases. We proposed a method of applying an antistatic agent, ultraviolet rays, or thermosetting surface hardening agent to form a thin film (Japanese Patent Application No. 1983, Japanese Patent Application Laid-open No. 1983-1993). Even in the case of the proposal, the film does not satisfy all of the solvent resistance, scratch resistance, and antistatic properties, and may be insufficient for practical use.

(Problems to be Solved by the Invention) ゛In view of the above points, we are conducting intensive research on anti-glare agents that can easily form an anti-glare film having solvent resistance, scratch resistance, and antistatic properties. The results showed that by combining alcoholic silica sol and UV-curable surface-curing resin, it can easily achieve adhesion, solvent resistance, scratch resistance, and antistatic properties on glass surfaces and synthetic resin board surfaces. It has been discovered that an anti-glare film-forming composition capable of forming an anti-glare film with excellent properties can be obtained, and the present invention has been completed. Then, by placing a synthetic resin plate treated with the novel anti-glare agent of the present invention on the front of various optical equipment (OA equipment, television cathode ray tubes, etc.), or directly treating the glass surface of the optical equipment. By doing so, visual impairment can be effectively prevented.

(Structure of the invention) The present invention has the following features! A composition for forming an anti-glare film comprising an alcoholic silica sol and a UV-curable surface-curing resin is blended with 2 to 5 parts by weight of the UV-curable surface-curing resin per 1 weight of silica.

Hereinafter, the specific configuration of the present invention will be explained in more detail.

The alcoholic silica sol that can be used is silicon tetrachloride, tetramethyl silicate, etc., which can be obtained by hydrolyzing a hydrolyzable silicon compound such as chlorosilane, carboxysilane, silyl isocyanate compound, or alkyl silicate in an alcohol solvent. , tetraethyl silicate.

Lower alkyl silicates such as tetra n-propyl silicate and tetra n-butyl silicate are preferred, and methyl silicate, which is a condensation product thereof, is preferred51. Ethyl silicate 40 may be used. These hydrolysis operations are carried out in an alcoholic solvent without a catalyst or in the presence of an acid catalyst according to conventional methods.

As such acid catalysts, both inorganic and organic acids can be conveniently used; the inorganic acids are preferably, for example, hydrochloric acid, sulfuric acid, phosphoric acid, phosphoric acid, etc., and the organic acids are, for example, formic acid,
Approximately 5% of acetic acid, oxalic acid, and p-toluel are preferably employed. Although the desired product can be obtained even if it is used in excess of 5%,
I can't expect particularly good results.

The amount of hydrolyzable silicon compound to be added is preferably such that the solid content (silica content) of the solution is 2 to 5% by weight.The amount of water to be added is determined so that the hydrolysis rate of the hydrolyzable silicon compound An amount of 70-500%, preferably 100-300% is used. The solvents used are methanol,
Alcohols such as ethanol, propatool and butanol are preferred.

The reaction temperature is preferably room temperature, but a higher temperature may be used, and the reaction time varies depending on the temperature and amount of catalyst, but is generally 1 to 48 hours.

There are two types of surface curing resins: ultraviolet curing type and thermosetting type.
Because the heating temperature is limited and the versatility is poor,
An ultraviolet curing type is preferred. As the ultraviolet curing surface curing resin, a wide variety of commercially available resins can be used. Particularly preferred are those soluble in alcohol.

The non-volatile residue in the anti-glare agent is preferably in the range of 5 to 15% by weight. If it is less than 5% by weight, the non-volatile residue in the droplets will decrease, and if the unevenness becomes vague, unevenness will occur, making it difficult to properly prevent the glare. It becomes difficult to obtain a dazzling effect.Furthermore, the adhesion strength decreases, and if it exceeds 15% by weight, the droplets become coarse and the particle size adhering to the surface of the synthetic resin plate increases, further causing unevenness. Also, an appropriate anti-glare effect cannot be obtained, and the resolution and appearance deteriorate.

The blending ratio of the silica component and the UV-curable surface-curing resin component in the non-volatile residue is such that the UV-curable surface-curing resin component is 2 to 5 parts by weight per 1 part by weight of the silica component. If the amount is less than 2 parts by weight, the adhesion to the surface of the synthetic resin board will be poor, and the solvent resistance and scratch resistance of the coating will be poor. On the other hand, if the amount exceeds 5 parts by weight, the particles adhering to the surface of the synthetic resin plate will become coarse, making it impossible to obtain a dense and uniform pattern.

The blended silica sol seems to have the effect of making the adhered particles finer and forming a dense pattern.

Moreover, in this case, the antistatic properties based on silica sol are also lost.

The alcoholic silica sol and the ultraviolet-curable surface-curing resin are blended by mixing them within the above-mentioned blending range. If the type of UV-curable surface-curing resin is difficult to dissolve in alcohol, a solvent that is compatible with both may be mixed, but it must be within a range that does not affect the synthetic resin board.

The composition for forming an anti-glare film obtained as described above was disclosed in a previous application by the present inventors (Japanese Patent Application No. 1983, Japanese Patent Application Laid-open No. 1988-1991, "Anti-glare treated synthetic resin plate and Its manufacturing method”
), by spraying it onto a glass surface or a synthetic resin plate surface and drying it by the following procedure, an excellent anti-glare effect can be imparted to these surfaces.

Spraying is carried out according to normal operations, and the diameter of the spray nozzle used greatly affects the anti-glare effect. That is, if the aperture is large, the droplets will be coarse and the uneven surface will be rough, which is unfavorable in terms of appearance, and the anti-glare effect will also be uneven. For this reason, the diameter of the nozzle is preferably 0.8+m or less, and a nozzle with a diameter of up to 0.4 m is advantageous as a small diameter that is cheap to obtain, but a diameter smaller than this is also acceptable.

The drying temperature is preferably as high as possible, below the softening temperature of the resin, but generally it is sufficient to maintain the drying temperature at a temperature of 50 to 60°C for 30 minutes to 1 hour.

In this way, the anti-glare agent can be sprayed to form a fine uneven layer on the glass surface or synthetic resin plate surface.
By controlling the amount of spraying, it is possible to adjust the anti-glare properties in various ways.

When the composition for forming an anti-glare film according to the present invention is sprayed onto a glass surface or a synthetic resin plate surface by the above operation, the gloss level is 4.
0 (according to JIS Z 8741), an anti-glare layer having high adhesion, solvent resistance, scratch resistance, and antistatic properties can be obtained.

Next, a manufacturing example of the composition for forming an anti-glare film according to the present invention,
The application of the adjusted anti-glare agent to the surface of a synthetic resin plate and the anti-glare performance will be explained in detail based on Examples, but the present invention is not limited thereto. Number of copies depends on weight.

(Example) Example 1 100 parts of isopropanol, 10 parts of water, 13 parts of tetraethyl silicate, and 0.5 part of concentrated hydrochloric acid were mixed and reacted at a temperature of 60° C. for 5 hours to produce Sin and 3% of tetraethyl. A silicate hydrolyzate (alcoholic silica sol) was obtained.

This hydrolyzed liquid was added to an ultraviolet curable surface curing resin (Unidek 17-824 manufactured by Dainippon Ink Chemical Co., Ltd., non-volatile residue 7).
Add 12 parts of
An anti-glare agent was prepared.

20 g of the obtained anti-glare agent was sprayed onto an acrylic resin plate with dimensions of 300 IX 20 C Il using a 0.4-caliber spray nozzle, and heated and cured at 70°C for 1 hour to achieve zero-order hardening. The coated film was irradiated with ultraviolet light using a 4 kV concentrating ultraviolet lamp at an irradiation distance of 15 m and an irradiation time of 5 seconds to cure the film.

Comparative Example 1 7 parts of the same ultraviolet curable surface curing resin used in Example 1 was added to 100 parts of isopropyl alcohol,
The mixture was stirred uniformly and used as comparative sample 1.

Comparative Sample 1 was sprayed in the same manner as in Example 1, and subjected to UV curing treatment in the same manner.

Comparative Example 2 Only the tetraethylsilicate hydrolyzate prepared in Example 1 was used.30. was spray-painted on a similar acrylic board using a 0.4 part diameter spray nozzle. This was cured and dried at 70°C for 1 hour.

Table 1 shows the results of each evaluation.

Table 1 * Glossiness was measured using a gloss needle according to the JIS Z8741 glossiness measurement method.

*Surface resistance was measured using a portable cavity resistance meter stack TR-3 (manufactured by Tokyo Electronics Co., Ltd.).

★Surface hardness measurement is based on JIS K-5400 (1979
)-6-14 Based on pencil scratch test.

★Solvent resistance is determined by soaking absorbent cotton in isopropyl alcohol and rubbing the treated surface strongly 50 times.If there is no change in the treated surface, it is 0. Those with changes were marked as ×.

*Adhesion was measured by attaching cellophane tape to the treated surface and instantly peeling it off, with no peeling of the film being taken as 0.

★Resolution measurement is done using MICROCOPY RESOL.
UTION TESTCIIART (NATIONA
L BUREAU OF 5TANDARDS-196
3-A) was used to visually judge the numerical value. A higher number indicates better resolution.

(According to this, the blank before coating was 8.0, while that of Example 1 was 8.0 (0), and that of Comparative Example 1 was 7.1.
(Δ), and that of Comparative Example 2 was 7.1 (Δ). ) As shown in Table 1, the anti-glare agent containing alcoholic silica gel (tetraethyl silicate hydrolyzate) and ultraviolet curable surface-curing resin according to the present invention has anti-glare properties (low gloss), electrostatic It exhibits excellent properties in all aspects of prevention (low surface resistance), high scratch resistance (surface hardness), solvent resistance, adhesion, and resolution.

On the other hand, the anti-glare agent (Comparative Example 1) consisting solely of an ultraviolet-curable surface-curing resin is inferior in anti-glare properties, antistatic properties, and resolution properties. Furthermore, the anti-glare agent made solely of alcoholic silica gel (Comparative Example 2) had good scratch resistance, solvent resistance, and adhesion.

It is inferior in resolution characteristics.

(Effects of the Invention) The following effects are expected from the composition for forming an anti-glare film comprising alcoholic silica gel and an ultraviolet curable surface-curing resin according to the present invention.

(i) It has excellent anti-glare properties as well as resolution properties, making it ideal as an anti-glare agent for optical equipment.
By applying anti-glare treatment to various optical devices such as devices and cathode ray tubes, it is possible to help prevent visual impairment.

(it) Since it has excellent antistatic properties as well as antiglare properties, it is possible to form an antiglare layer that does not attract contaminants such as dust and dirt.

(iii) Anti-glare properties as well as surface hardness, solvent resistance,
Since it has excellent adhesion, a stable anti-glare layer can be formed on the surface of the object to be treated.

('y) Since the anti-glare coating can be formed by spraying or treatment, the anti-glare effect can be easily and arbitrarily controlled.

Claims (1)

[Claims] 1. A composition for forming an anti-glare film comprising an alcoholic silica sol and an ultraviolet curable surface-curing resin. 2. The composition for forming an anti-glare film according to claim 1, which has a non-volatile residual content of 5 to 15% by weight. 3. The composition for forming an anti-glare film according to claim 2, wherein the composition of the nonvolatile residue is 1 part by weight of silica and 2 to 5 parts by weight of an ultraviolet curable surface-curing resin.