JPS61209152A - Glare shield film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to anti-glare films, and more particularly to anti-glare plastic films with improved scratch resistance.

Prior Art Glass products, plastic films, etc. with glossy surfaces cause specular reflection, which makes it difficult to see objects on the back side or images from the back side, causes discomfort to the viewer, and may cause eye irritation. It is well known that it causes fatigue.

For example, when viewing images on a cathode ray tube, specular reflections from windows or fluorescent lights overlap the image, making it difficult to see, which is a daily experience.Also, when viewing images or scales through a glass case, Have a similar experience. Such specular reflection development is used in various fields, especially cover glasses such as display cases, clocks, measuring instruments, etc.

This has been a problem in optical display surfaces or front panels of cathode ray tubes, liquid crystal displays, light emitting diode displays, etc., and methods for preventing this have been studied and proposed.

To prevent the specular reflection phenomenon, in other words, to prevent glare, it is sufficient to reduce the brightness, clarity, etc. of the reflected image of the external light source.For example, (1) a thin film of metal oxide, fluoride, etc. (2) A method of reducing the brightness of the reflected image by making use of the light interference phenomenon (2) By incorporating special dyes and pigments into the light transmitting material and utilizing the light absorption phenomenon, Method for Reducing (3) A method is known in which the clarity of the reflected image is reduced by providing fine irregularities on the surface of the light transmitting body or by providing a thin film having fine irregularities to scatter the light.

The first method is a useful method for reducing the clarity of the reflected image, but it is difficult to reduce the reflectance to zero in the entire visible light range, so in reality, only a portion of the reflected image There are some drawbacks that remain.

The second method is useful for applications such as front panels of light-emitting display devices, but it has the disadvantage that if dyes, pigments, etc. are added to the extent that the reflected image is eliminated, the resolution of the transmitted image will drop too much. be.

The third method is an effective method for reducing the clarity of the reflected image. As a procedure for forming fine irregularities, coating a paint containing silicon oxide particles has been practiced for a long time. However, it is difficult to form fine irregularities that are uniform and have excellent anti-glare properties.For example, this paint uses fine secondary aggregates of silicon oxide, so the dispersion method is difficult and the quality is unstable. , the shape is unstable and the surface of the thin film is severely uneven, which tends to lower the resolution of the transmitted image.

Therefore, these improvements are desired. Furthermore, when anti-glare properties are imparted to a plastic film, scratch resistance, antistatic properties, moisture resistance, etc. are required depending on the application, and there are also requirements for preventing damage and 1. Flexibility is required to allow installation on curved sections.

OBJECTS OF THE INVENTION An object of the present invention is to provide an anti-glare plastic film that satisfies the above-mentioned required performance.

According to the present invention, an object of the present invention is to provide an anti-glare film in which an anti-glare thin film is provided on a transparent plastic film, the thin film is made of a thermosetting resin containing zeolite, and the surface It has fine irregularities with a roughness of 0.1 to 0.8 μm, and the change in light transmittance due to the thin film is within 10% of the light transmittance of the plastic film. This is achieved by an anti-glare film that is 10 to 80 times as strong as bone skin.

Examples of the plastic film in the present invention include films of polystyrene, polymethyl acrylate, polycarbonate, polyacetate, polysulfone, polyester, etc., which have excellent transparency. Among these films, polyester films, particularly oriented polyester films, are particularly preferred. Examples of the polyester include aromatic dibasic acids such as terephthalic acid, inphthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, or their ester-forming derivatives, and ethylene glycol and propylene glycol.

1,3-propanediol, 1,4-butanediol.

Neopentyl glycol, 1,5-bentanediol,
A high melting point synthesized using a diol such as 1,6-hexanediol, 1,4-cyclohexane dimetatool, etc. or an ester-forming derivative thereof.

Highly crystalline linear polyesters are preferred.

Specific examples of such polyesters include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly(1,4-cyclohexylene dimethylene) terephthalate, and the like. Furthermore, these copolymers or blends may also be used. Among these, polyethylene terephthalate is particularly preferred. It is well known that a polyester film with high light transmittance, low osteoderm, and excellent transparency can be produced by appropriately selecting inorganic particles added at the film forming stage, for example. Furthermore, when the surface of the polyester film is coated with an organic solvent-based paint, it has the advantage that it is less prone to deterioration and swelling due to solvents and has excellent mechanical properties. The light transmittance of the plastic film is preferably 80% or more, more preferably 85% or more.

The anti-glare thin film can be obtained by applying a coating material basically consisting of a surface-curing binder, zeolite particles and a solvent onto a transparent plastic film, and then curing the binder with heat.

At that time, in order to improve the dispersibility of zeolite particles,
A dispersant such as a surfactant may be blended, and a small amount of an anti-settling agent, wetting agent, leveling agent, etc. may also be added.

The surface-curing binder is a thermosetting resin, such as a phenol resin, an amino resin, an epoxy resin, a thermosetting acrylic resin, an unsaturated polyester resin, and a polyurethane resin that is cured by reaction with the thermosetting resin. , a compound or a mixture containing an alkyd resin or the like.

Specific examples include a combination of melamine resin, urethane resin and alkyd resin, a combination of thermosetting acrylic resin, polyester resin and melamine resin, a combination of epoxy resin and melamine resin, etc. can be given. The higher the light transmittance, the more preferable these are.

The filler forms fine irregularities in the thin film and has the effect of scattering reflected light. However, light scattering generally occurs not only as described above but also on the filler surface inside the thin film, and this scattering is influenced by the shape of the filler, the refractive index (difference between the refractive index of the binder and the filler), and the like. Since this scattering causes disturbance in the transmitted image and reduces the clarity of the facial image, it is necessary to avoid this scattering as much as possible. The filler used in the present invention is zeolite particles. These zeolite particles have a refractive index of 1.49, which is close to that of the thermosetting resin used as the binder, and are cubic to prismatic in shape.If the addition of filler is optimized, the surface of the film after coating can be improved. It has the advantage that it can be made into a smooth uneven shape.

Among zeolite particles, synthetic zeolite particles are particularly preferred because they have a narrow and uniform particle size distribution and have good dispersibility in paints. The average particle size of the zeolite is preferably 1 to 6 μm. If this particle size is too small, the surface shape of the thin film formed will be too flat and will not exhibit anti-glare effects, and if it is too large, the surface unevenness of the thin film will be too large, and a large amount of binder will be required to wrap the particles, resulting in an increase in coating thickness. This is undesirable because the film becomes thick and the film curls significantly when the coating is thermally cured. The amount of zeolite added is preferably 5 to 20% by weight based on the binder. If the amount of zeolite added is too small, the light transmittance will be high, but the reflected light will also be strong and the anti-glare performance will deteriorate. On the other hand, if the amount of zeolide added is too large, interparticle aggregation may occur, the unevenness of the coating film surface may become irregular, and the diffusion component becomes high with respect to the transmission of light, resulting in a marked increase in haze and a marked decrease in transparency. It becomes cloudy. In forming a coating film by coating the above-mentioned paint on a plastic film, coating methods include barcode method, doctor blade method, reverse coating method,
Gravure coating method.

Conventionally known methods such as the comma coat method can be used. The coating thickness after drying is preferably in the range of 1 to 10 μm from the viewpoint of the scratch resistance of the coating film and the adhesion of the filler. If the coating film becomes too thick, the film will curl significantly due to shrinkage during the heat curing process. Thermal curing of the coating film is
This may be carried out simultaneously with the drying of the coating layer, or may be carried out separately. When carrying out simultaneously, it is preferable to carry out at a temperature of 130° C. or higher, although it depends on the heat resistance (dimensional stability under heat) of the plastic film. When carried out separately, it is preferable to dry at a temperature lower than the above temperature and then cure at the above temperature. The heat curing time varies slightly depending on the curing speed of the resin, but usually about 5 to 10 minutes at 130°C and about 2 to 4 minutes at 150°C are sufficient.

By selecting the above-mentioned conditions, a thin film having fine irregularities with a surface roughness of 0.1 to 0.8 μm is formed on the plastic film. This thin film only changes the light transmittance of the plastic film by less than 10%, has excellent light transmittance, and after treatment, the osteoderm of the film is 10 to 80 times larger than that of the plastic film. , has light scattering performance.

The degree of anti-glare due to this light scattering is determined by the measurement method described later.
00% or less, preferably 80% or less. If this value becomes high, the anti-glare properties will deteriorate, which is not preferable.

The anti-glare film of the present invention may be subjected to metal vapor deposition or fluorine compound thin film treatment on the coated surface or back surface for purposes such as ultraviolet reflection and electrostatic shielding.

Effects of the Invention The anti-glare transparent film of the present invention has excellent anti-glare properties, scratch resistance, etc., and is flexible, so it can be used for, for example, cathode ray tubes, instrument 2 display boards, liquid crystal displays, light emitting diode displays, etc. It can be advantageously used as an anti-glare cover film for products in which the specular reflection phenomenon is a particular problem, such as, and can also be used as a front plate (front film) of a light emitting display device, a liquid crystal display, an instrument 1 display board, etc.

EXAMPLES The present invention will be explained below with reference to Examples. The various properties of the coated film were measured according to the following methods.

(1) Surface roughness Ra value: Tokyo Seimitsu Co., Ltd. stylus type surface roughness meter (3urcon 8B
), run a needle with a radius of 2 μm over the coated film surface under a load of 0.1 g, and
The students were asked to draw a chart magnified 2,000 times vertically on the surface. Measurement length L (
Take out the part of L=2m+) and draw the center line of this part as
The roughness curve is given by the following formula with the 11th direction as the Y axis and the roughness curve as Y-f(X,).(2) Light transmittance and bone skin (haze): According to JIS K-7105 (1981), Integrating sphere type light transmission device (Nippon Denshoku Kogyo ■ “Haze Meder ND”)
The light transmittance and osteoderm (haze) of the film were measured using a H-2D model.

3) Anti-glare degree: according to JIS K-7105 (1981), incident angle 2
The degree of anti-glare was determined from the reflection intensity ζS at the time of G'.

In addition, the reflection intensity is measured by a glossiness measuring device! (Murakami Color Research Institute■
Glossmeter GM-3M).

Anti-glare level Qs (20) - ζS/ζo X 100ζO
: Reflection intensity of standard plate (black plate) ζ0: Reflection intensity of sample (4) Pencil hardness: According to JIS K-5400 (1979), a pencil of various hardness was applied to the film surface at an angle of 90°, and a load of 1K was applied.
It is expressed as the hardness of a pencil when a scratch occurs on the film surface when scratched under g.

(4) Scratch-resistant Nisteel wool $0000 was used to manually rub the film surface 3 to 4 times, and the occurrence of scratches was visually determined.

Examples 1 to 4 and Comparative Examples 1 to 3 As thermosetting resins, 60 parts by weight of thermosetting acrylic (Hitachi Chemical, trade name "Hitaloid 240OA") and melamine resin (Hitachi Chemical, trade name "Melan 20") were used. 40
Part by weight was dissolved in 250 parts by weight of a mixed solvent of methyl ethyl ketone and toluene (1:1).

To this solution, synthetic zeolite type A particles (manufactured by Toyo Soda Co., Ltd., trade name "Toyo Builder", average particle diameter 1.5 μm) were added in the amount shown in Table 1, and dispersed in a ball mill for 1 day. The paint thus prepared was applied to a commercially available polyester film (Yojin ■, product name "Tetron" film Q-100).
It was uniformly coated with a bar coater so that the thickness after drying was 3 to 5 μm, and then dried at 150° C. for 3 minutes to perform heat curing. The performance test results of the obtained coating film are shown in Table-1. From the results in Table 1, it can be seen that the films of Examples 1 to 4 have excellent anti-glare properties, high light transmittance, and excellent scratch resistance, and are useful as anti-glare films.

Examples 5 to 8 and Comparative Example 4 The thermosetting binder solution of Example 1 was added with an average particle size of 4.1μ.
m synthetic zeolite CD eoussa company, product name “S”
PERNAT44") was blended in the amounts shown in Table 2, and a paint was prepared using a ball mill.

This paint was uniformly coated on the same polyester film as that used in Example 1 using a bar coater so that the film thickness after drying was 4 to 6 μm, and then dried at 150°C for 3 minutes and heat cured. I made him do it.

The performance test results of the obtained coating film are shown in Table-2.

From the results in Table 2, the films of Examples 5 to 8 have excellent anti-glare properties, high light transmittance, and excellent scratch resistance.
It can be seen that it is useful as an anti-glare film.

Claims (1)

[Claims] 1. An anti-glare film in which an anti-glare thin film is provided on a transparent plastic film, the thin film being made of a thermosetting resin containing zeolite and having a surface roughness of 0.1 to 0. .8μm
The film has fine irregularities, and the change in light transmittance due to the thin film is within 10% of the light transmittance of the plastic film, and the haze of the anti-glare film is 10 to 80 times that of the plastic film. An anti-glare film characterized by the following. 2. The antiglare film according to claim 1, wherein the average particle size of the zeolite is 1 to 6 μm, and the content thereof is 5 to 20% by weight based on the thermosetting resin. 3. The anti-glare film according to claim 1 or 2, wherein the thermosetting resin is a thermosetting product of thermosetting acrylic resin and melamine resin.