JPS6168231A - Preparation of glare-proof film - Google Patents

Abstract

PURPOSE:To inexpensively prepare a glare-proof film for making the picture of a cathode ray tube sharp, by coextruding a transparent three-layered laminate having an intermediate in which a small amount of carbon black is dispersed and applying matte or satin processing to the surface thereof. CONSTITUTION:Polymethylpentene having 1wt% of carbon black compounded therein is used as an intermediate layer 2 and transparent polymethylpentene layers 1, 3 are arranged to both sides of said intermediate layer 2 to perform coextrusion while the surface 4 of the first layer is subjected to matte or satin processing by an emboss roller or process paper so as to adjust the center average roughness thereof to 0.1-50mum. The resulting film uniformly absorbs light in a visible light region and can be easily prepared.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is suitable for use in television cathode ray tubes, computer display screens, and automobile instrument display boards by controlling the amount of light in the visible light range and blocking external light. , relates to a method of manufacturing an anti-glare film that makes the screen clear.

[Prior art]

The recent development of the electronics industry is remarkable, and the application fields of electronic devices are expanding in various fields.

With the use of cathode ray tubes in televisions and the display screens of office computers, which have been increasing rapidly over the past few years, as more people spend longer periods of time looking at them, problems such as ease of viewing and eye strain become a problem, requiring specialized operators to operate these devices. Among humans, poor eyesight is considered an occupational disease and even tends to become a social problem.

Furthermore, recently there has been a noticeable trend toward digitalization of automobile instruments, and amidst the wave of design innovations for instrument panels, there is a need for materials that can control the amount of light in the visible light range and satisfy design freedom and safe driving. In order to meet these demands, the number of anti-glare films used is rapidly increasing.

Conventional anti-glare films even out the amount of light in the visible light range.

A combination of various dyes has been added to glass bases and gelatin pastes to absorb -, but it is inevitable that the dyes will change color or fade during long-term use.

Further, glass has disadvantages in that it cannot take a free shape and is easily broken, and gelatin is sensitive to moisture and water, so if the film becomes dirty, it cannot be easily cleaned. Also, if it is left in a high humidity atmosphere for a long period of time, mold will grow, which is a fatal phenomenon.

Furthermore, with conventional anti-glare films, it is necessary to finely adjust the amount of dye added to control the amount of light.
The current situation was that production costs had to rise.

[Purpose of the invention]

The present invention was developed as a result of extensive research into the possibility of applying coextrusion technology to a manufacturing method that could produce anti-glare films at low cost, which was not possible using known manufacturing methods. It was discovered that this performance exists in a transparent thermoplastic resin (B) in which a small amount of carbon blank is uniformly dispersed. Conventionally, by coextruding thermoplastic resins (8) and (C) with excellent heat-fusion and transparency, and processing the surface of the thermoplastic resin or C) to have a matte or satin finish immediately after extrusion, This makes it possible to produce an anti-glare film at a low production cost that would be unimaginable using the same manufacturing method.

[Structure of the invention]

In the present invention, the first layer is a thermoplastic resin (A) with excellent transparency.
The second layer is a transparent thermoplastic resin 03) that can be thermally bonded to the thermoplastic resin (A) and has a small amount of carbon black uniformly dispersed therein, and the third layer is a transparent thermoplastic resin 03) that can be thermally bonded to the thermoplastic resin (A), and the third layer is a transparent thermoplastic resin 03) in which a small amount of carbon black is uniformly dispersed. Co-extrusion is performed with a composition of a second layer transparent thermoplastic resin (B) having excellent transparency, which is the same as or different from the plastic resin (A), and a thermoplastic resin (C) that can be heat-fusible. Immediately thereafter, the surface of the first layer or the third layer is processed to have a matte or matte finish and a center average roughness of 0.1 to 50 μm. be.

The present invention will be explained in detail with reference to the drawings. FIG. 1 is a cross-sectional section of a composite film coextruded according to the present invention. 1.3 is a thermoplastic resin with excellent transparency (C), and 2 is a transparent thermoplastic resin in which a small amount of carbon black is uniformly dispersed. Further, the surface 4 of the first layer is matte or satin-like, and has been processed so that the center average roughness of the surface is 0.1 to 50 μm.

Thermoplastic resins with excellent transparency used in the present invention include polyamide, polymethyl methacrylate, polymethylpentene, polycarbonate, polystyrene, polyethersulfone, polyetherimide, polysulfone, and the like. However, from the viewpoint of moldability and cost, polymethylpentene and polycarbonate are most preferred.

Also, carbon black can be acetylene black, oil furnace black, thermal black, channel black, etc., but the most important thing is how to uniformly disperse a small amount of carbon.The crosstalk machine is not particularly limited, but When the dispersion is observed with an electron microscope, it is desirable that the carbon black be uniformly dispersed so that no aggregates of carbon are present at all and no shading of the dispersion of carbon black is observed. This is because if a large number of bicarbon aggregates exist, the incoming light will be scattered by the aggregates, making it impossible to absorb each hue in the visible light range on average.

In the present invention, the surface of the coextruded film can be made matte or matte by bringing the surface to be processed of the coextruded 3-Jei composite film into contact with a cooling roll having a predetermined embossed finish, or by applying a desired surface roughness. Immediately after coextrusion, the process paper for forming the replica is laminated by roll pressure bonding and then peeled off.

〔Effect of the invention〕

The method for producing an anti-glare film of the present invention makes it possible to produce this type of film, which was previously considered very expensive, at a low cost.For example, in the conventional case, when producing a film with different light intensity control, the amount of dye added is changed. However, in the present invention, only the thickness of the intermediate layer to be coextruded, which is a transparent thermoplastic resin (B) in which a small amount of carbon is uniformly dispersed, is changed during extrusion, and the total thickness of the three layers is changed. teeth,
This is possible by not changing it.

〔Example〕

(1) Polymethylpentene (Mitsui Petrochemical Industries ■TPX
MXOO4) Carbon black (
Denki Kagaku Kogyo (Denka Black) was kneaded to uniformly disperse 1 part by weight of Comparand t--as an intermediate layer (2 in Figure 1), and both outer layers (1.3) were coextruded with the above-mentioned polymethylpentene. Immediately after extrusion, the composite film was bonded to a processing paper using a roll to achieve a lamination strength of 1500 mL.
/an pressure bonding, after cooling the film, peel off the process paper,
An antiglare film was obtained in which the intermediate layer had a thickness of 10 μm, the outer layers each had a thickness of 30 μm, and the center line average roughness of the surface of the transparent polymethylpentene layer was 20 μm.

When the absorption of this anti-glare film in the visible light region was investigated, an absorption spectrum as shown in FIG. 2 was obtained.

(2) Polycarbonate (Kijin Kasei ■ Panlight -1
300) Comparand in which 100 parts by weight of carbon black (Cabonoto C5X-99) 1.51 parts was uniformly dispersed was used as the intermediate layer 2 in Fig. 1, and both outer layers 1.3 were made of the above polycarbonate. Extruded.

Immediately after extruding the composite film, it was pressed onto an embossing roll to form a transparent polycarbonate layer having a satin-like surface with a center line roughness of 10 μm, an intermediate layer thickness of 5 μm, and both outer layers each having a thickness of 50 μm. I got a dazzling film.

When the absorption in the visible light region of the anti-glare film was investigated, an absorption spectrum as shown in Figure 3 was obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the anti-glare film of the present invention, and FIGS. 2 and 3 are diagrams showing absorption spectra in Example 1 and Example 2. Patent Applicant: Sumitomo Bakelite Co., Ltd. Figure 1 Figure 2 Mi fL gain (nm) Figure 3 Dependency (nm)

Claims (3)

[Claims] (1) The first layer is a thermoplastic resin (A) with excellent transparency, and the second layer is a transparent resin that can be thermally bonded to the thermoplastic resin (A) and has a small amount of carbon black uniformly dispersed therein. The third layer is a thermoplastic resin (B), and the third layer is a thermoplastic resin (B) of the first layer.
A thermoplastic resin (A) with excellent transparency that is the same as or different from A) and capable of being thermally fused to the transparent thermoplastic resin (B) of the second layer.
Perform coextrusion with the configuration of C), and immediately after extrusion, process the surface of the first layer or third layer so that it is matte or satin-like and the center average roughness of the surface is 0.1 to 50 μm. A method for producing an anti-glare film characterized by: (2) The method for producing an anti-glare film according to claim 1, wherein the thermoplastic resins (A), (B) and (C) are polymethylpentene. (3) The method for producing an anti-glare film according to claim 1, wherein the thermoplastic resins (A), (B) and (C) are polycarbonate.