JPS59179535A - Method for forming metallized film giving irregular reflection - Google Patents

Abstract

PURPOSE:To obtain a metalized film giving irregular reflection and suitable for a light-diffusion sheet for liquid crystal display, etc., by carrying out the first process comprising the coating of the surface of a sheet substrate with a liquid paint containing light-scattering particles, followed by the drying and curing of the coating film, and the second process comprising the formation of a metallized film composed of a metal or a metallic compound. CONSTITUTION:The surface of a sheet substrate is coated with a liquid paint composed of (A) 100pts.wt. of a film-forming substance curable with heat or UV- radiation and having high adhesivity to the sheet substrate, (B) 0.5-30pts.wt. of light-scattering particles (e.g. plastic powder having an average particle diameter of 2-15mum) and (C) a solvent, and the coating film is dried and cured to obtain a roughened surface. A metallized film composed of a metal or a metallic compound is applied to the roughened surface to obtain the objective coating film. USE:Screen for video projector, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a diffusely reflective vapor deposited film on the surface of a sheet-like substrate.

Examples of methods for forming a diffusely reflective vapor deposited film on the surface of a sheet-like substrate include a method in which the surface of a sheet-like substrate is first matted and then a metal vapor-deposited film such as aluminum is formed thereon;
A method of coating a metal powder material on the surface of a sheet-like substrate is known.

However, these conventional methods have the problem that matte processing and powder coating in order to obtain stable diffuse reflection characteristics are time-consuming, making it difficult to make them industrially inexpensive and mass-produced.

Further, for applications such as video projector screens and light diffusion sheets for liquid crystal displays, methods aiming at a wide half-width in optical performance have not been able to fully satisfy this point.

This invention was discovered as a result of intensive studies from the above viewpoint, and its gist is to coat the surface of a sheet-like substrate with a liquid paint containing light-diffusing particles that has good adhesion to the substrate. A diffusely reflective vapor deposited film characterized by comprising a first step of roughening the surface of the substrate by drying and curing, and a second step of forming a vapor deposited film made of a metal or a metal compound on the roughened surface. It is in the method of formation.

In the first step of this invention, a liquid paint containing light-diffusing particles is used, and the paint components include A) a heat-curable or ultraviolet-curable film-forming substance that has good adhesion to a sheet-like substrate, and B) It contains light-diffusing particles and C) a solvent, and other additives such as a curing agent, a photopolymerization initiator, a viscosity modifier, a surfactant, and an anti-aging agent are used as necessary.

As component A, a resin with good adhesion to a sheet-like substrate is selected from among ultraviolet curable acrylic urethane resins, thermosetting polyester resins, acrylic resins, butyral resins, urethane resins, and the like.

Component B is preferably a solvent-insoluble spherical material such as plastic powder or glass powder (silica powder), with an average particle size of 80 ttm or less, most preferably an average particle size of 2-
Narrow beads with a particle size distribution in the 15 μm range are preferred.

Component B is effective for roughening the surface of the coating film, and in order to obtain stable diffuse reflection characteristics, the surface must have a uniform surface roughness, and with the above-mentioned specific beads, this purpose can be easily achieved. I can do it.

Generally, it is desirable that the blending ratio of the A and B components is such that the B component is 05 to 30 parts by weight per 100 parts by weight of the A component. If the B component is too small, it will be difficult to effectively diffuse the incident light, and if it is too large, it will not reflect evenly.
Problems arise with filling properties, coating properties, etc.

Component C is selected from a component that can dissolve component A and is inert to the sheet-like substrate. The amount is determined within a wide range, but usually the total solids concentration in the paint is between 20 and 80.
The ratio may be set to about % by weight.

Using a liquid paint consisting of such ingredients, first coat the surface of a sheet-like substrate with an appropriate means such as a gravure coater, a reverse roll coater, etc., which are common solution coating means.
Coating is performed using a spray coater, slot orifice coater, etc. so that the thickness after drying and hardening is approximately 5 to 801 tm. After this coating, heat curing or ultraviolet curing is performed depending on the type of component A.

The sheet-like substrate used here is a plastic snack sheet made of polyester resin, polycarbonate resin, polypropylene resin, polyvinyl chloride resin, polyacrylic resin, polysulfone resin, etc., but is not particularly limited thereto.

By forming the above-mentioned cured coating film, the surface of the sheet-like substrate can be easily and uniformly roughened. The surface roughness is determined by the solid content concentration of the paint, the average particle diameter and amount added of the light-diffusing particles, the film thickness, etc., so it is desirable to appropriately set the above-mentioned factors depending on the required diffuse reflection characteristics.

In the second step of the present invention, a vapor deposited film made of a metal or a metal compound is formed on the coated surface of the sheet-like substrate. The means for forming the deposited film is not particularly limited, and a resistance heating method, an electron beam evaporation method, an induction heating method, etc. can be employed.

As a continuous vapor deposition method, the material is fed into a vacuum chamber,
A winding type semi-continuous device having a winding mechanism can be used. Moreover, when the sheet-like substrate to be vapor-deposited is a single plate, a cassette-cassette type continuous vapor deposition apparatus is used.

The vacuum evaporation chamber is designed to maintain a degree of vacuum of, for example, I x 10-4 Torr, and single metals such as Sn+ cr l Nl, ZN, Ni-Cr, Ni-Fe, etc., placed in a resistance heating crucible are , Fe-C
In addition to alloys such as o, A4□03.5102, TlO
Metal oxides such as metal oxides such as No. 2 and metal salts such as AgBr and AgCl are heated and vapor-deposited using a heater made of heat-resistant nichrome wire.

The thickness of the vapor-deposited film made of metal or metal compound formed in this way can be adjusted by controlling the transfer speed of the sheet-like substrate and the evaporation amount of the evaporation source, and is generally about 300X to 1)tm. It is said that

The vapor-deposited film obtained in this way exhibits stable and very good diffuse reflection properties because the sheet surface is uniformly roughened by the underlying coating film, and is used as a light diffusion sheet for video projector screens and liquid crystal displays. It can be effectively used for various purposes.

As detailed above, according to the method of the present invention, in the first step, a predetermined liquid paint is applied to the surface of the sheet-like substrate by a normal coating means and cured by heating or ultraviolet rays,
After that, in the second step, a deposited film with stable diffuse reflection characteristics can be obtained by a simple method of vacuum evaporation, and this method has the advantage of being able to provide a large quantity of products at low industrial cost because it is easy to perform continuously. be.

Examples of this invention will be described below. In the following, parts shall mean parts by weight.

Example 1 Using a predetermined amount (parts) of the predetermined components shown in Table 1 below, they were thoroughly mixed using a high-speed stirrer, and the filtration accuracy was 10 t.
Four types of liquid paints, including one for comparison, were prepared by filtration using a filter of T.

Table 1 (Notes) 1) Byron #2002 manufactured by Toyobo Co., Ltd.) Coronate L manufactured by Nippon Polyurethane Co., Ltd. 3) Sumika beads manufactured by Sumitomo Chemical Co., Ltd. (average particle size 611 m) 4) Toluene/ethyl acetate - 1/1 (weight ratio) These liquid paints are applied to a polyester resin sheet as a sheet-like substrate using a reverse roll coater at a line speed of 2Q.
+n After applying for 7 minutes and drying by heating at 130℃ for 1 minute,
A rough coated surface with an average coating thickness of 4 μm was obtained.

Next, the coated sheet with the rough surface is fed into a vacuum chamber, and A
It was set up in a continuous apparatus capable of depositing 1. The pressure of this was reduced to 5×1 O −5 Torr using a vacuum pump. Next, while continuing the vacuum, the resistance heating crucible is heated so that the AI in the crucible has an average thickness of i, o o on the sheet surface.
The thickness was adjusted to be oλ. At this time, the winding speed was 10 m/min, the deposition rate was 400 k/sec, and the atmospheric pressure was I.
X 10-'Torr.

The 60 degree specular reflectance of the vapor deposited film thus obtained was measured using a variable angle photometer (GI)-IR manufactured by Murakami Color Research Institute), and the microbeads (light diffusing particles) in each paint were measured. The results of examining the relationship between the amount of addition of and the above reflectance were as shown in FIG.

Further, the relationship between the reflection angle and the reflectance was investigated for the one using paint No. 8, and the results were as shown in FIG.

Example 2 Using a predetermined amount (parts) of the predetermined ingredients listed in Table 2 below,
Four types of liquid paints were obtained by processing in the same manner as in Example 1, and each of these paints was further processed in the same manner as in Example 1 to obtain a rough coated surface with an average coating thickness of 4 μm.

Table 2 (Note 5) is Takelac A-310/A manufactured by Takeda Pharmaceutical Co., Ltd.
-8=12/H weight ratio) 6) ? ) are the same as those listed in Table 1. Next, AA was vapor-deposited on the coated surface of the above-mentioned coated sheet by the resistance heating method in the same manner as in Example 1. 6 of the vapor deposited film thus obtained
The 0 degree specular reflectance was measured and the relationship between the solid content concentration in each paint and the reflectance was investigated, and the results were as shown in FIG.

As is clear from Figures 1 to 3 above, by appropriately setting the content of light diffusing particles and solid content concentration in the liquid paint, it is possible to form a deposited film with excellent diffuse reflection properties. I understand that.

[Brief explanation of drawings]

Figure 1 is a characteristic diagram showing the relationship between the amount of microbeads (light diffusing particles) added to the paint and the reflectance when a diffusely reflective vapor deposited film is obtained by the method of the present invention, and Figure 2 is a characteristic diagram showing the relationship between the reflectance and the amount of microbeads (light diffusing particles) added in the paint. FIG. 3 is a characteristic diagram showing the relationship between the solid content concentration in the paint and the reflectance when a vapor deposited film is obtained. FIG. 3 is a characteristic diagram showing the diffuse reflection characteristics of the diffuse reflection vapor deposited film obtained by the method of the present invention. Patent Applicant Nitto Electric Industry Co., Ltd. Figure 1 Figure 2 IIJ 2'A IL (Weight 010) Figure 3

Claims (1)

[Claims] (l) A first step of roughening the surface of the substrate by coating the surface of the sheet-like substrate with a liquid paint containing light-diffusing particles that has good adhesion to the substrate and drying and curing it; 1. A method for forming a diffusely reflective vapor deposited film, the method comprising the step of forming a vapor deposited film made of a metal or a metal compound on a surface.