JPS6157322A - Manufacture of dazzling-free film - Google Patents

Abstract

PURPOSE:To manufacture a dazzling-free film at low cost, by a method wherein a small quantity of carbon is made to keep dispersed evenly into an inner layer of a three-tiered resin layer which is to be coextruded. CONSTITUTION:As for a first layer, a resin composite to be obtained by kneading 100pts.wt. polypropylene and 20pts.wt. talc is laminated in 200mum thick, as for a second and fourth layers, polycarbonate is laminated in 200mum each and as for a third layer, which is an inner layer between the second and fourth layers, a composite to be obtained by dispersing evenly the 100pts.wt. polycarbonate and 1.5pts.wt. carbon black is laminated in 5mum thick, which are coextruded into a four-tiered layer and a composite four-tiered composite sheet is obtained. Then after cooling of the sheet, a polypropylene resin composite, which is the first layer, is peeled off an a dazzling-free film having the surface in a satinlike state is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to television cathode ray tubes, computer display screens, and automobile instrument display boards to control the amount of light in the visible light range and to block external light. This invention relates to a method for producing an anti-glare film that makes the screen clearer.

[Prior art]

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

The display screens of office computers, which have been increasing rapidly over the past few years, including cathode ray tubes in televisions, have become increasingly difficult to read, and as more and more people look at them for long periods of time, problems such as ease of viewing the screen and eye fatigue have arisen. Among professional operators, there is even a tendency for vision loss to become an occupational disease and a social problem.

Furthermore, recently there has been a noticeable trend toward digitalization of automobile instruments, and amid the wave of design innovations for instrument panels, there is a demand 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 amount of anti-glare films used is rapidly increasing.

Conventional anti-glare films have been made by adding a combination of various dyes to a glass space or gelatin base in order to uniformly absorb the amount of light in the visible light range, but the dyes tend to discolor or fade during long-term use. was unavoidable. In addition, 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. Furthermore, 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 co-extrusion technology to a method of manufacturing an anti-glare film at a low cost, which was not possible using known manufacturing methods. It was discovered that this performance exists in a transparent thermoplastic resin (C) in which a small amount of carbon black is uniformly dispersed, and the first layer contains an inorganic filler of 50 to 1
50 parts by weight is added, and the second layer is a polyolefin resin that does not heat-seal, the second layer is a highly transparent thermoplastic resin (B), and the third layer is a thermoplastic resin. (B
) and the above-mentioned transparent thermoplastic resin (C) that can be thermally fused with
The fourth layer is a thermoplastic resin having excellent transparency, which is the same as or different from the thermoplastic resin (B) of the second layer, and which can be thermally fused with the transparent thermoplastic resin (C) of the third layer. By performing coextrusion with the composition of resin (D) and then peeling off the first layer,
The inventors have discovered that it is possible to produce an anti-glare film at a lower cost than ever before, and have completed the present invention.

[Structure of the invention]

In the present invention, the first layer contains an inorganic filler of 15 to 150%,
The second layer is a polyolefin resin composition (2) that is added in parts by weight and is not heat fused to the second layer, and the second layer is a highly transparent thermoplastic resin (6). Plastic resin (
The fourth layer is a transparent thermoplastic resin (C) that can be thermally fused with B) and has a small amount of carbon black uniformly dispersed therein. The same or different thermoplastic resin 03) with excellent transparency, and the third waste transparent thermoplastic resin (
A method for producing an anti-glare film characterized by co-extruding a composition of C) and a thermoplastic resin (6) which can be thermally fused, and then peeling off the first layer. Detailed explanation of. FIG. 1 is a cross-sectional view of a coextruded composite film of the present invention.

1 is a polyolefin resin composition containing an inorganic filler, 2.4 is a thermoplastic resin with excellent transparency, (6)
3 is a transparent thermoplastic resin (C) in which a small amount of carbon black is uniformly dispersed. When the layer of polyolefin resin composition (a) of 1 of the 4-layer composite film shown in FIG. 1 is peeled off, the 3-layer composite film shown in FIG. 2 is obtained. Surface 5 of the layer of thermoplastic resin (B) with excellent transparency in 2 of Fig. 2
has a matte or satin-like surface.

The polyolefin resin used in the present invention includes polyethylene, polypropylene, ethylene/vinyl acetate copolymer, ionomer, polybutadiene, ethylene/propylene copolymer, ethylene/acrylic acid ester copolymer, etc. Polyethylene and polypropylene are preferable because they have excellent layer transparency and do not exhibit coextrusion moldability or heat fusion properties with thermoplastic resins.

As the inorganic filler added to the polyolefin resin, silica, Merck, calcium carbonate, clay, etc. are used. If the amount of inorganic filler added is 50 parts by weight or less, it is
The surface of the thermoplastic resin (B) of the layer will not become sufficiently matte, and if it exceeds 150 parts by weight, extrusion molding will become extremely difficult.

Thermoplastic resins with excellent transparency used in the present invention include polyamide, polymethyl methacrylate, polymethylpentene, polycarbonate, polystyrene, polyether sulfone, polyetherimide, polysal 7one, and the like. However, from the viewpoint of moldability and cost, polymethylpentene and polycarbonate are most preferred.

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. When observing the dispersion under a magnification of 10,000 times, it is desirable that the carbon black be uniformly dispersed so that no aggregates of carbon exist at all and no shading of the carbon black is observed. This is because if a large number of carbon 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.

〔Effect of the invention〕

By the method for producing an anti-glare film of the present invention, such a film, which was conventionally considered to be very expensive, can be produced at low cost.
For example, in the past, when creating films with different light intensity controls, this was done by changing the amount of dye added, but in the present invention, a small amount of carbon, which is the intermediate layer to be coextruded, is uniformly dispersed. Transparent thermoplastic resin (B)
Only the thickness of the second layer and the fourth layer were changed during extrusion, and the total thickness of the three layers was made by kneading 120 parts by weight of calcium carbonate with 100 parts by weight of Sumikasen G701) to a thickness of 50 μm. The layer contains polyterpene (Mitsui Petrochemical Industries 5 TPX MXOO4) with a thickness of 30 μm each, and the third layer contains 100 parts by weight of the above polymethylpentene and carbon black (Denka Black from Denki Kagaku Kogyo).
A four-layer composite film with a thickness of 10 μm was coextruded with 1 part by weight of Konibound uniformly dispersed, and after cooling the film, the first
The polyethylene resin composition of the layer was peeled off to obtain an anti-glare film having a surface of a transparent polymethylpentene layer with a center line average roughness of 20 μm.

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

(2) As the first layer, polypropylene (Sumitomo Chemical Co., Ltd.)
Noblen FC-240) 3 parts of talc to 100 parts by weight
A resin composition mixed with 0 parts by weight was prepared with a thickness of 200 μm,
2nd/! And the fourth layer is polycarbonate (Teijin Kasei ■
Panrye) K-1300) with a thickness of 100 μm each, and carbon black (Cabot C3X-99) 1.
A 4-layer composite sheet with a thickness of 5 μm was coextruded with 5 parts by weight of the compound uniformly dispersed, and after cooling the film, the first
The polypropylene resin composition of the layer was peeled off to obtain an antiglare film having a satin-like surface with a center line average roughness of 10 μm on the surface of the transparent polycarbonate layer. When the absorption of this anti-glare film in the visible light region was investigated, an absorption spectrum as shown in FIG. 4 was obtained.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the intermediate composite film of the present invention;
The figure is a cross-sectional view of the anti-glare film of the present invention, and FIGS. 3 and 4 are diagrams showing absorption spectra in Example 1.2. Patent applicant: Sumitomo Bakelite Co., Ltd. Figure 2

Claims (3)

[Claims] (1) The first layer is a polyolefin resin composition (A) to which 15 to 150 parts by weight of an inorganic filler is added and which is not thermally bonded to the second layer. The third layer is a thermoplastic resin (B), and the third layer is a transparent thermoplastic resin (C) that can be thermally bonded to the thermoplastic resin (B) and has a small amount of carbon black uniformly dispersed therein. The second layer
Co-extrusion with a thermoplastic resin (D) having excellent transparency, which is the same as or different from the thermoplastic resin (B) of the layer, and which can be thermally fused with the transparent thermoplastic resin (C) of the third layer. 1. A method for producing an anti-glare film, the method comprising the steps of: carrying out an anti-glare film, and then peeling off the first layer. (2) The method for producing an anti-glare film according to claim 1, wherein the thermoplastic resins (B), (C) and (D) are polymethylpentene. (3) The method for producing an anti-glare film according to claim 1, wherein the thermoplastic resins (B), (C) and (D) are polycarbonate.