JPS6332161B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that at least the three elements of an acrylic film, a uniformly thick light-diffusing layer, and an acrylic synthetic resin plate are integrated, and the light-diffusing layer is a thin layer of acrylic resin. The present invention relates to a method of manufacturing an acrylic laminated high light diffusing plate which is covered so as not to be exposed to the outside.

Acrylic high light diffusion plates, which are made by coating an acrylic synthetic resin plate with a suitable high light diffusion agent, have traditionally been used for rear projection screens.
For example, it has been used in fields such as daylight screens (screens that allow the projected image to be clearly seen even in bright places).

Modern high-grade rear projection screens use light diffusing agents (powdered glass, titanium oxide,
A mixture of silicon oxide, calcium carbonate, etc.) and a coloring agent with a binder and a diluent is applied onto one side of a commercially available acrylic synthetic resin board, styrene synthetic resin board, polycarbonate board, etc., using a spray method, a spin coating method, etc. It is generally manufactured by coating by a coating method such as a roll coating method or a flow coating method, followed by drying and solidification.

The characteristics that a rear projection screen should have include total light transmittance, gain, reflectance, haze value, light diffusivity, bending angle, contrast, and resolution. Although there are differences in degree depending on the item, when a certain type of light diffusing agent is specified, it is governed by the uniformity of the thickness of the light diffusing layer.

Against this background, conventional manufacturing methods require a great deal of effort and attention to make the thickness of the high light diffusion layer uniform, and force application is a complicated and skill-intensive process that requires a lot of manpower. Furthermore, there are restrictions on the size of the acrylic synthetic resin plate, etc. to be coated. Furthermore, the process of drying and curing the coated high light diffusion layer has to be carried out carefully for each layer, which requires a lot of manpower and space. Furthermore, since the light-diffusing layer is exposed to the outside world, it is easily damaged, and it is necessary to take great care in removing dust.

The present invention was invented to improve these drawbacks and efficiently produce an excellent light intensity diffusion plate. A monomer or partial polymer having the same composition as the acrylic synthetic resin is applied to form a thin film layer R, and an acrylic film F' on which a high light diffusion layer P is previously laminated on one side is supplied and pressed. Then, the monomer or partial weight, which is the raw material for the acrylic synthetic resin plate L, is injected from one end into the space surrounded by the two belts and a pair of gaskets supplied at both ends using a syringe. The present invention provides a method for manufacturing an acrylic laminated high light diffusing plate, which is characterized by continuously supplying acrylic materials and polymerizing and curing them to integrate them.

The present invention will be explained in more detail below.

First, an example of an acrylic laminated high light diffusion plate manufactured according to the present invention will be explained with reference to FIG. 1. Both A and B are high light diffusion plates obtained according to the present invention.

In these figures, L is an acrylic synthetic resin plate serving as a substrate, F is an acrylic film for supporting a high light diffusion layer to be described later, P is a high light diffusion layer, and F' is a high light diffusion layer P. R represents a laminated acrylic film, and R represents a thin film layer made of a monomer or partial polymer having the same composition as the acrylic synthetic resin.

The present invention is formed as described above, but the acrylic film F is partially dissolved and swollen by the monomer or partial polymer that is the raw material for the acrylic synthetic resin plate L, and is then polymerized and hardened. Because they are integrated together, they are laminated extremely firmly.

However, the high light diffusion plate obtained by the present invention is
Since the high light diffusion layer P is covered by the thin film layer R and is protected from being exposed to the outside, it is difficult to get scratched when used in practical use, and the high light diffusion layer P is also damaged when removing dust. It has the effect of never happening.

Examples of the acrylic synthetic resin board L serving as the base material of the present invention include colorless or appropriately colored methyl methacrylic resin boards, including monoethylenically unsaturated resins that can be copolymerized with 90% by weight or more of methyl methacrylate and other Colorless or suitably colored synthetic resin plates made of compounds and/or copolymers with polyfunctional compounds may also be mentioned.

Examples of the monoethylenically unsaturated compound include methacrylic esters, acrylic esters, and styrene. Examples of the polyfunctional compound include methacrylic acid esters such as glycol dimethacrylate and diallyl methacrylate, diallyl phthalate, diethylene glycol bisallyl carbonate, and mixtures thereof.

In the present invention, the acrylic synthetic resin plate L is supplied as a monomer or a partial polymer as a raw material.

Furthermore, the acrylic film F used in the present invention
A polymer (including a multilayer polymer) whose main component is an alkyl methacrylate such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, or propyl methacrylate,
For example, Japanese Patent Publication No. 49-46159, Japanese Patent Publication No. 51-
Films which are alkyl methacrylate-based polymers having a multilayer structure disclosed in JP-A-129449, JP-A-52-56120, US Pat. No. 4,052,525, JP-B-47-13371, etc. are preferred. In addition, a film of an alkyl methacrylate copolymer disclosed in Japanese Patent Publication No. 52-26901 may also be used. Each of the above polymers is formed into a film by itself, but if necessary,
It may be mixed with the alkyl methacrylate polymer disclosed in Japanese Patent No. 58554 and formed into a film, and these films may also be used.

Furthermore, a high light diffusion layer P formed in the present invention
consists of a light diffusing agent, an acrylic polymerizable binder, and additives added as necessary. As a light diffusing agent, acrylic synthetic resin board,
Different (generally larger) refractive index than the acrylic synthetic resin thin film layer R or acrylic film F
Any material having a refractive index may be used, but it is particularly composed of silicon oxide, various silicates (e.g. calcium silicate), titanium oxide, magnesium oxide, talc, bromite, or at least two of these. Mixtures may be mentioned. The particle size of the light diffusing agent is in the range of 1 to 100μ, preferably 1 to 100μ.
A range of 20μ is appropriate.

In the present invention, a thin film layer R of acrylic synthetic resin is coated on the surface of the high light diffusion layer P for the purpose of protecting it, and the thin film layer R is composed of methyl methacrylate and other copolymerizable monoethylenically unsaturated A mixture or partial polymer selected from the group of compounds and/or polyfunctional compounds, the viscosity range of which is
It is manufactured from 1000 cps or less, preferably 10 to 500 cps.

Next, the manufacturing method of the present invention will be explained. As shown in FIG. The raw material for the acrylic synthetic resin plate L is introduced from one end into the space surrounded by continuous gaskets 7 and 7' running between both belt surfaces near the ends of these surfaces. A monomer or partial polymer is supplied, heated as the endless belts 1, 1' run, polymerized and hardened, cooled, separated from the endless belts 1, 1' from the other end, and taken out as an acrylic synthetic resin plate. A continuous plate making method is used.

In manufacturing the acrylic high light diffusion plate shown in FIG. 1A or B of the present invention, a methyl methacrylate partial polymer was stored in the hold tank 171 of the coating device 17 shown in FIGS. 2 and 3. tank 171
The amount of coating can be adjusted by adjusting the nitrogen pressure or liquid level pressure applied to the liquid and/or the number of gauze sheets 172 and/or the rotation (squeezing) angle of the rotating rotor 173. Combine the upper endless belt 1
A method of applying an appropriate amount is adopted.

As shown in FIG. 2, an acrylic film supply device 15 is installed downstream of the coating device 17, and a fourth
As shown in the figure, an acrylic film F' on which a high light diffusion layer P has been formed in advance on one side is placed on a feed roller 151, pinch rollers 152, 152',
152″, 152 and guide roller 153,
153', the press roller 15 is continuously supplied in accordance with the running speed of the upper endless belt 1.
4 to the upper endless belt 1.

The monomer or partial polymer, which is the raw material for the acrylic synthetic resin plate L, passes through a gear pump 5 and is sent from an injector 6 to face the upper endless belt 1 to which the acrylic film F' is attached. It is injected between the surfaces of the lower endless belt 1' and into the space surrounded by the gaskets 7, 7'.

The injected monomer or partial polymer, which is the raw material for the acrylic synthetic resin plate L, is mixed together with the acrylic film F' attached to the upper endless belt 1 as the belts 1 and 1' run. The material enters the first polymerization zone 18 and is heated and polymerized by spraying hot water of 50 to 95 DEG C. onto the back surface of the endless belts 1 and 1' using spray devices 8 and 8'. Next, it enters the second polymerization zone 19 and is heat-treated at 115 to 150°C by far infrared heaters 9 and 9'.

Furthermore, the plate-shaped polymer sandwiched between the upper and lower endless belts 1, 1' passes through the first cooling zone 10 and the second cooling zone 11, and then reaches a temperature of 105°C or lower, preferably 100°C or lower.
After being cooled to 80°C, it is taken out from the other end of the opposing endless belts 1, 1'. The running speed of the endless belts 1, 1' is preferably 0.5 to 4.0 m/min.

A specific example will be explained below.

Example 1: Manufacturing an acrylic film F' on which a high light diffusion layer P is coated in advance.

Various existing industrial methods can be applied to form the high light diffusion layer P on one side of the acrylic film F in advance. That is, while continuously supplying the acrylic film F onto a belt running at a constant speed, a suspension of light diffusing agent is applied to one side of the film F using a flow coater, a roll rotor, etc. At this time, a portion of the acrylic film swells and dissolves, coming into close contact with the high light diffusion layer and becoming integrated.)
After that, it dries, hardens, and peels off from the belt.

Alternatively, when it is desired to make the thickness of the high light diffusion layer P more uniform, in the above method, a light diffusion agent suspension is applied to the belt surface, an acrylic film F is supplied from the top surface of the belt, and a press roll is applied. By press-bonding (at this time, a part of the acrylic film F swells and dissolves, adheres closely to and integrates with the high light diffusion layer), the thickness of the high light diffusion layer P is made uniform, and then dried and hardened. After that, peel it off from the belt.

Example 2 Manufacture of acrylic high light diffusion plate.

Prepolymerized methyl methacrylate monomer to contain approximately 30% by weight of polymethyl methacrylate, 25
A methyl methacrylate partial polymer is produced with a viscosity of about 1000 cps at °C. This was combined with 650 ppm of azobisdimethylvaleronitrile as a polymerization catalyst, 30 ppm of dioctyl sulfosuccinate, 80 ppm of carbon black, and cyanine blue as a release agent.
Add 10ppm and mix. As shown in FIG. 2, this mixture is continuously supplied between the endless belts 1 and 1' from an injector 6 at a constant flow rate using a gear pump 5. The thickness of endless belt 1, 1' is
Made of polished stainless steel, 1.5 mm wide and 1500 mm wide, pulleys 2 and 2' with a diameter of 1600 mm provide tension between them and pulleys 3 and 3', and the tension in the endless belts 1 and 1' is controlled by hydraulic pressure. Yotsute 10Kg/
mm ² and run at a speed of 2.5 m/min.

On the other hand, the hold tank 171 of the coating device 17
Add the methyl methacrylate partial polymer and apply it on the upper belt. The methyl methacrylate partial polymer put into the hold tank 171 of this coating device 17 is 23% by weight of polymethyl methacrylate.
It contains 500 ppm of azobisdimethylvaleronitrile as a polymerization initiator, 100 ppm of dioctyl sulfosuccinate as a release agent, and has a viscosity of 80 cps at 25°C.

The coating device 17 stores the methyl methacrylate partial polymer in a hold tank 171 as shown in FIG. In this case, the amount of dripping applied depends on the running speed of the endless belts 1, 1' and the coating thickness, depending on the nitrogen pressure or liquid level pressure applied to the tank, the number of gauze sheets 172, and/or the rotation (squeezing) angle of the rotating rotor 173. adjusted accordingly.

The method of operating the acrylic film supply device 15 is as follows.

For example, a 50μ thick acrylic film F consisting of 64% by weight of methyl methacrylate and 36% by weight of butyl acrylate is used, and a high light diffusion layer is previously formed on one side of the film by the method described in Example 1. is continuously supplied to the upper endless belt 1 from the film supply device 15.

More specifically, the above acrylic film
F' is supplied by a film supply device 15 shown in FIG. That is, from the feed roller 151, the pinch rollers 152, 152', 152'',
152 and guide rollers 153, 153', and is sent together with the upper endless belt 1 while being pressed by a press roller 154 to the thin film layer R of the methyl methacrylate partial polymer coated on the upstream side.

A part of the acrylic film F' is swollen and dissolved by the methyl methacrylate monomer in the thin film layer R of the methyl methacrylate partial polymer on the downstream side after the press roller 154, but the upper endless belt 1 and the temperature (40 to 60°C), some of the monomers polymerize before reaching the position of the pulley 2, and are cured and integrated with the thin film layer R.

In this way, the acrylic film F' is integrated with the thin film layer R and reaches the position of the injection port 6 together with the upper endless belt 1, and together with the methyl methacrylate partial polymer supplied from the injection port 6, the two opposing It is sandwiched between the endless belts 1 and 1' and sent.

The distance between the two endless belts 1 and 1' is such that the methyl methacrylate polymer of the resulting acrylic high light diffusion plate has a uniform thickness of 2 mm (the plate thickness is 0.5 to 15 mm).
It can be freely changed within the mm range. ) so that
It is held by roller groups 4, 4' arranged at 400 mm intervals. For gaskets 7 and 7', the outer diameter
13.0mm, wall thickness 0.8mm, polymer as plasticizer.
A hollow polyvinyl chloride pipe containing 44 parts by weight of dibutyl phthalate is used.

The acrylic film F' side that is attached to the upper belt 1 of the two running endless belts 1 and 1', the lower belt 1' side and the gasket 7,
The methyl methacrylate partial polymer fed between 7' advances to the first polymerization zone 18. The length of the first polymerization zone 18 is 66 m, and the spray devices 8, 8' spray warm water at 84 DEG C. onto the back surfaces of both the endless belts 1, 1' like a shower to heat them. By this heating, the methyl methacrylate partial polymer is substantially polymerized and cured to become a plate-like polymer.

The acrylic film F' is heated until it reaches the first polymerization zone 18 by the methyl methacrylate monomer in the methyl methacrylate partial polymer supplied from one end of the two endless belts 1 and 1'. Partially swelled and dissolved, but the first polymerization zone 1
In step 8, the polymer is polymerized and cured together with the methyl methacrylate partial polymer to form a plate-shaped polymer.

In the first polymerization zone 18, the methyl methacrylate plate polymer integrated with the acrylic film F' advances to the second polymerization zone 19 as the two endless belts 1, 1' run. The length of the second polymerization zone 19 is 24 m, and the endless belts 1, 1' in contact with the plate-shaped polymer are heated to 140° C. by far-infrared heaters 9, 9'. At the outlet of the second polymerization zone 19, the temperature was 127°C.

The plate-shaped polymer having left the second polymerization zone 19 advances to the first cooling zone 10 as the endless belts 1, 1' run. The length of the first cooling zone 10 is 5.4 m, and the temperature is reduced to 103°C at a cooling rate of 14.4°C/min by blowing air vertically onto the back surface of the endless belts 1 and 1' using a blower. cooled down. The length of the second cooling zone 11 is 3m
Then, the plate-shaped polymer is cooled to 80° C. by blowing air, separated from the endless belts 1 and 1', and taken out.

The product that was taken out and integrated with the acrylic film F', the high light diffusion layer P, and the acrylic synthetic resin plate L has an excellent thickness accuracy of 2 ± 0.15 mm, and the acrylic film F' No wrinkles occur,
It was an excellent product with no visible spots in the high light diffusion layer P.

In this example, it can be easily understood that the product shown in FIG. 1A or B can be obtained by supplying the acrylic film F' in a different direction.

[Brief explanation of the drawing]

1A and 1B show an acrylic high light diffusion plate obtained according to the present invention, FIG. 2 is a front view of an apparatus for carrying out the manufacturing method of the present invention, and FIG. 3 is a view of a coating apparatus. FIG. 4 is a front view of the film supply device. 1, 1'...Endless belt, 15...Film supply device, 17...Coating device, F...Acrylic film, F'...High light diffusion layer forming acrylic film,
L...Acrylic synthetic resin plate, P...High light diffusion layer, R
...thin film layer.

Claims (1)

[Claims] 1. A monomer or partial polymer having the same composition as the acrylic synthetic resin is coated on one of two belts running opposite each other to form a thin film layer R, and a high light diffusion layer P is preliminarily applied on the thin film layer R. The acrylic film F' laminated on one side is supplied and crimped, and then injected from one end into the space surrounded by the two belts and the pair of gaskets supplied to the end of the surface using a syringe. A method for manufacturing an acrylic laminated high light diffusion plate, which comprises continuously supplying monomers or partial polymers, which are raw materials for the acrylic synthetic resin plate L, and polymerizing and curing them to integrate them.