JP2000317964A - Device and method for manufacturing synthetic resin plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously manufacture synthetic resin plates of superior dimension accuracy with high productivity by driving one of a pair of endless belts set horizontally, also driving the other belt followingly and providing a synthetic resin plate polymerization raw material between the belts in the first half of a polymerization zone with average pressure of given value. SOLUTION: A pair of endless belts 1 and 1' are wound and disposed on an upstream side and a downstream side rotating drums 2, 3 and 2', 3' so as to make belt faces opposing each other travel by the same speed in the same direction. A synthetic resin polymerizing raw material is fed from a raw material into a space encircled by the belt faces facing each other of the belts 1 and 1' and continued gaskets 7 and 7' traveling on both side sections of the belt faces, and a synthetic resin plate 12 is taken out of the other ends of the belts 1 and 1' through heating zones 13 and 9-9' and cooling zone 10 and 11. The average pressure of 0.25 kPa or more is applied to the polymerization raw material between the belts in the heating zones 13. The synthetic resin plates 12 of plate thickness accuracy and free from deflections, cracks, foams and the like can be continuously manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously producing a synthetic resin plate or an artificial marble plate, and more particularly to a method of curing a synthetic resin plate raw material using a continuous curing device using two endless steel belts. The present invention relates to a method for continuously producing a synthetic resin plate or an artificial marble plate, which is characterized by being produced by the above method.

[0002]

2. Description of the Related Art Acrylic artificial marble is a slurry obtained by mixing a large amount of a powdered inorganic filler, a marble pattern developing particle (marble chip), various additives, a curing initiator, a pigment, etc., with an acrylic component. A mixture in the form of a plate is injected into a mold or the like, and then cured by an appropriate curing device to produce a plate-shaped product. The plate-shaped product is then subjected to an edge trimming and a surface polishing process to produce a final product. Such an acrylic artificial marble plate is made of a nonporous material whose surface and inside are uniform and is solid. It is easy to cut, grind, bend by heat, join with an adhesive, etc. The demand for building internal materials such as the upper plate of sinks, various counters, washing stands, and wall materials is increasing.

[0003] As a method for producing an acrylic synthetic resin plate, including such an acrylic artificial marble plate, usually,
A casting method and a continuous manufacturing method are employed. The mold method is disclosed in JP-A-52-36155 and JP-A-53-1129.
No. 90, for example. In the mold method, the mixture is poured into a mold that is formed by placing a resin gasket on two metal plates or glass plates and pressing with a clamp, performing primary curing and secondary curing in a water tank or air circulation oven, and then removing the mold. This is a method of dismantling and obtaining the final product. However, such a method is a batch-type operation, so that the operation is complicated, the production cost is increased, and the productivity is extremely low. Therefore, streamlining by continuous operation has been demanded.

[0004] A production method for making the above-mentioned mold method continuous (Japanese Patent Publication No. 47-34815 and Japanese Patent Publication No.
No. 5818, JP-B-49-36944, etc.) have been considered. In this method, a pair of two endless steel belts provided on the upper and lower sides of which the opposing surfaces run in the same direction and at the same speed, a device for continuously supplying a resin gasket between both sides in the width direction of the belt, and an appropriate heating The polymerizable mixture is continuously injected into the space formed by the belt and the gasket by using a curing device including a cooling device and the like, and is continuously polymerized according to the movement of the belt to form a plate-like product into the device. It is a method to take out from the exit. In particular, JP-B-49-35818 and JP-B-49-369.
No. 44 is characterized in that the belt surface is inclined.

[0005] US Patent No. 3,570,
No. 056 discloses a method of continuously injecting an acrylic resin plate polymerization raw material into a continuous curing device composed of one endless steel belt and an auxiliary device, and continuously curing the material according to the movement of the steel belt. It discloses a method of producing a product in the shape of a letter. In the same gazette, after pouring a film on the endless belt surface, pour the polymerization raw material,
A method of covering the polymerization raw material with another film is also disclosed.

[0006] Of these methods, the methods disclosed in Japanese Patent Publication Nos. 49-35818 and 49-36944 use a belt that is tilted or curved, so that it is difficult to obtain a product having sufficient thickness accuracy. is there.

Also, US Pat. No. 3,570,
In the method disclosed in Japanese Patent No. 056, polymerization is performed in a space formed by one endless belt and a film. Therefore, even with this method, it is difficult to obtain a product having sufficient plate thickness dimensional accuracy.

On the other hand, a method for producing an acrylic artificial marble plate is disclosed in Japanese Patent Application Laid-Open No. 9-512303, WO 98/177.
No. 13, JP-A-10-217264 and the like, there is shown an example in which a continuous production method of an acrylic plate containing no inorganic substance is applied to production of an acrylic artificial marble plate.

[0009] However, Japanese Patent Publication No. 9-512303 and WO 98/17713 disclose the aforementioned Japanese Patent Publication No. 49-177313.
No.-35818 and JP-B-49-36944 are applied to the production of an acrylic artificial marble plate, and it is difficult to obtain a product with sufficient plate thickness and dimensional accuracy because the belt is used with an inclined or curved belt. It is. Japanese Patent Application Laid-Open No. Hei 10-217264 is an application of the method of the aforementioned U.S. Pat. No. 3,570,056 to the production of an acrylic artificial marble plate, which is formed by one endless belt and a film. Since polymerization is performed in a space, it is difficult to obtain a product having sufficient thickness accuracy.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art.
An object of the present invention is to provide a continuous manufacturing apparatus and a continuous manufacturing method capable of continuously manufacturing a synthetic resin plate having excellent dimensional accuracy with high productivity by using a pair of endless belts as a curing device. Further, there is provided a continuous production apparatus and a continuous production method of an acrylic artificial marble plate capable of continuously producing an acrylic artificial marble plate having excellent dimensional accuracy with high productivity using a pair of two endless belts as a curing device. With the goal.

[0011]

According to the present invention which solves the above-mentioned problems, a pair of endless belts running opposite to each other are disposed near both ends of the pair of endless belts, and the pair of endless belts A gasket that runs following the running of the belt in a sandwiched state, and continuously heat-polymerizes the synthetic resin plate polymerization raw material in a space formed by the facing surfaces of the pair of endless belts and the gasket. In the synthetic resin plate manufacturing apparatus, the pair of endless belts are installed substantially horizontally, one of the pair of endless belts is driven by belt driving means, and the other is driven to follow the other. And at least in the first half of the polymerization zone, the synthetic resin plate polymerization raw material interposed between the pair of endless belts is 0.25 kPa Apparatus for manufacturing a synthetic resin plate, wherein a pressure applying device for applying an average pressure of the upper is disposed is provided.

Further, according to the present invention, a pair of endless belts running opposite to each other, and arranged near both side ends of the pair of endless belts, following the running of the belt while being sandwiched between the pair of endless belts Using a polymerization apparatus having a gasket that travels while running, and injecting a synthetic resin plate polymerization raw material into a space formed by the opposed surfaces of the pair of endless belts and the gasket, and continuously heating and polymerizing the synthetic resin plate. In the manufacturing method, the pair of endless belts are installed substantially horizontally, and one of the pair of endless belts is driven by belt driving means, and the other belt is driven by following the belt driving means. In the first half, an average pressure of 0.25 kPa or more is applied to the synthetic resin plate polymerization raw material interposed between the pair of endless belts. Method for producing a synthetic resin plate, characterized in that there is provided.

As described above, in the present invention, a pair of endless belts are installed horizontally, and one endless belt is driven by belt driving means, and the other endless belt is driven to follow the endless belt. In the first half of the polymerization section, an average pressure of 0.25 kPa or more is applied to the synthetic resin plate polymerization raw material interposed between the endless belts. For this reason, it is possible to realize a plate thickness accuracy not available in the prior art and to continuously produce a synthetic resin plate free from bending, cracks, bubbles, dents and the like. In particular, when a thin synthetic resin plate is manufactured, it is possible to provide the synthetic resin plate with dimensional accuracy and appearance in a region that cannot be achieved by the conventional technology.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an average pressure of 0.25 kPa or more is applied to a synthetic resin plate polymerization raw material interposed between a pair of endless belts at least in the first half of the polymerization section. `` Polymerization zone '' refers to a region in which a pair of endless belts are opposed to each other via a synthetic resin plate polymerization raw material and is being heated. A predetermined pressure is applied. When a plurality of heat treatment steps are provided, it is preferable that a predetermined pressure be applied when the polymerization raw material is charged into the production apparatus and undergoes the first heat treatment.

The pressure applied to the synthetic resin plate polymerization raw material is 0.1.
25 kPa or more, preferably 0.5 kPa or more.
By doing so, good dimensional accuracy and appearance can be obtained. The upper limit of the pressure is not particularly limited, but is, for example, 50 kPa or less.

The present invention has a particularly remarkable effect when applied to continuous production of a thin synthetic resin plate. When manufacturing a synthetic resin plate having a thickness of 6 mm or less, particularly a synthetic resin plate having a thickness of 4 mm or less, it is difficult to obtain an excellent appearance while maintaining good dimensional accuracy with the conventional technology. According to the present invention, good dimensional accuracy and good appearance can be realized even with such a thin synthetic resin plate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall side view of an apparatus embodying the present invention, in which a pair of endless belts (1) and (1 ') are moved upstream so that opposing belt surfaces run in the same direction and at the same speed. Downstream rotating drum (2) (3), (2 ')
Wrap around (3 ') and arrange. The pair of endless belts (1) and (1 ') are surrounded by opposing belt surfaces and continuous gaskets (7) and (7') running while being sandwiched between the belt surfaces on both sides. Into the molding space, a synthetic resin plate polymerization raw material is supplied from a raw material injection device (6) arranged at the upstream end thereof, and the first heating zone (13), the second heating zone (9) (9 ′), After passing through the first cooling zone (10) and the second cooling zone (11), the endless belt (1) (1 ′) as a synthetic resin plate
2 shows a continuous plate making apparatus that is taken out from the other end of the plate making apparatus. 2
Each of the endless belts is characterized by being installed substantially horizontally, and a synthetic resin plate having high plate thickness accuracy can be obtained. Of the two endless belts having opposing belt surfaces, only one of them is directly driven by a motor (16), and the other belt is driven by raw materials, products, and other inclusions between the belt surfaces. , The two endless belts run in the same direction and at the same speed.

In the present invention, one or both of the molding surfaces of the pair of endless belts may be provided with a film for providing an uneven pattern on the synthetic resin plate. For example, in order to transfer various uneven patterns to one or both surfaces of an acrylic resin synthetic resin plate, one or both of the molding surfaces of the endless belt from the upstream end is incompatible with the synthetic resin plate polymerization raw material, and various uneven patterns are formed. It is also possible to use an apparatus for continuously supplying a film processed in advance.
At this time, an adhesive liquid such as liquid paraffin or liquid polyethylene glycol is used between the belt and the film so that no air layer such as air bubbles is trapped between the belt and the film, and the film is not in contact with the belt and damaged. Can be interposed. As an advantage of attaching a film to the surface of the endless belt (1) (1 ′), in addition to the transfer of the surface pattern, it is possible to easily separate the product and the belt surface at the exit of the device after the completion of curing. . In the present invention, the material of the film is polyethylene terephthalate,
Polyvinyl alcohol, polyethylene, nylon, polypropylene and the like can be used, but the polymerization temperature (generally 60 to 130) is used to prevent wrinkles on the product surface.
° C) under the condition that the heat shrinkage rate is small or close to the shrinkage rate in the plane direction at the time of polymerization of the polymerization raw material, and in consideration of mold releasability and strength, polyethylene terephthalate,
It is preferable to use polyvinyl alcohol.

The raw material for the synthetic resin plate polymerization is a raw material injection device (6).
Through the endless belt (1 ′). As the material injection device (6), Japanese Patent Publication No. 60-31
No. 643 can be used. Also,
A synthetic resin plate having a flowing pattern can also be obtained by using the method described in Japanese Patent Publication No. 3-5287.

When producing an acrylic artificial marble plate according to the present invention, an acrylic component (syrup), a filler and, if necessary, a small amount of a dispersant, a crosslinking agent, a light stabilizer, a polymerization initiator and a pigment Is mixed in a stirring mixer, and degassed under vacuum to produce an acrylic artificial marble plate polymerization raw material, and then charged into the continuous plate making apparatus of the present invention. The mixed acrylic-based artificial marble board polymerization raw material is continuously fed into the endless belt (1 ') via the raw material injection device (6). An artificial marble plate having a flowing pattern can also be obtained by using the method described in Japanese Patent Publication No. 3-5287. The viscosity range of the acrylic artificial marble board polymerization raw material to be injected is preferably 0.6 to 10 Pa · s at room temperature, and particularly preferably 0.6 to 5 Pa · s. If the viscosity is too low, the filler sediments in the acrylic component during polymerization, which is undesirable because the product value is reduced. If the viscosity is too high, it is difficult to feed the liquid to the injection device (6), or it may not be cast after being injected onto the endless belt, which is not preferable.

As the material of the gaskets (7) and (7 '), those generally used conventionally, for example, soft polyvinyl chloride are used. Other than polyethylene, flexible plastic, natural rubber and the like can also be used.

As a gasket supply device, Japanese Patent Publication No. 51-
It is preferable to use the device described in Japanese Patent No. 33826, and it is preferable to return the gasket which has been flattened for storage to its original shape by steam or electric heating and supply it between the upper and lower belts.

The gasket is Japanese Patent Publication No. 47-3349.
As described in Japanese Patent Laid-Open No. 7, publication No. 7 can also be used to arrange a double configuration using four lines. Accordingly, even when a water-soluble film is adhered to the belt surface and used, if the film is held by the inner gasket and has a width that does not protrude to the outside of the outer gasket, the first heating zone (13) described later can be used. Hot water can be used as the heating method.

The supplied polymerization raw material is interposed between the upper endless belt (1) while moving with the endless belt (1 '), and is transferred into the first heating zone (13).

In the first heating zone (13), it is important to apply an average pressure of 0.25 kPa or more to the synthetic resin plate polymerization raw material between the belts. Average pressure 0.25
If it is less than kPa, there is a possibility that a defect may occur on the surface of the synthetic resin plate, and in particular, in the production in a mode in which the film is attached to the belt surface described above, the film is transferred to the surface of the synthetic resin plate with wrinkles and dents, The product may have low commercial value, or it may be difficult to separate the synthetic resin plate from the film. 0.25 for synthetic resin plate polymerization material between belts
As an example of an apparatus for applying an average pressure of kPa or more, as a belt surface holding mechanism, a plurality of pairs of rollers (4) each axis of which is orthogonal to the belt running direction and supported by a shaft, and a frame (14) on the upper side of the belt A spring (15) installed in the belt running direction to adjust the average pressure of 0.25 kPa or more to the synthetic resin plate polymerization raw material between the belts. Especially the first
It is preferable to apply an average pressure of 0.5 kPa or more in the most upstream polymerization zone in the heating zone.

As a heating method of the first heating zone (13), a method of blowing hot air to the outside of the belt as described in Japanese Patent Application No. 5-25670, and a method of heating hot water as described in Japanese Patent Publication No. 47-33495. In addition to the method of spraying in the form of a shower, there are a method of running in a hot water bath, a method of using infrared rays, and the like. JP-B-58-49167 and JP-B-58-49167
As described in JP-A-49168, a method of providing a temperature distribution by adjusting the distribution of the hot water shower in the width direction of the belt and the upper and lower belt surfaces is also a preferable method for the purpose of improving the thickness accuracy. As the temperature of the hot water, any temperature of 100 ° C. or less can be used, but it is preferable to polymerize as quickly as possible in order to avoid an increase in the size of the apparatus and to increase the productivity.

In the second heating zone (9) (9 '), a far-infrared heater, an air furnace or the like is installed as described in JP-B-47-33495 to heat-treat the raw material mixture to complete the polymerization.

Next, cooling is performed in the cooling zones (10) and (11), and a synthetic resin plate as a product is continuously taken out.

As a raw material for polymerizing the synthetic resin plate in the present invention, for example, an acrylic component is used, which is mainly composed of a partial polymer of methyl methacrylate, and another monomer which is mainly composed of methyl methacrylate and is copolymerizable therewith. A methyl methacrylate-based partial polymer such as a partial polymer obtained from a mixture is used. Other copolymerizable monomers include:
For example, methacrylates such as butyl methacrylate and 2-ethylhexyl methacrylate; acrylates such as ethyl acrylate and butyl acrylate;
Maleimide derivatives such as N-phenylmaleimide and N-cyclohexylmaleimide; hydroxy-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; vinyl esters such as vinyl acetate and vinyl benzoate Classes: Nitrogen-containing monomers such as methacrylamide and acrylonitrile; Epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate; Polymerizable aromatic compounds having an ethylenically unsaturated bond in the molecule such as styrene and α-methylstyrene And the like. Such an acrylic component is partially polymerized in a continuous or batch reactor for process compatibility, or polymethyl methacrylate is dissolved in methyl methacrylate to form an acrylic syrup having a polymer content in the range of 10 to 35% by weight. It is preferable to use it after being manufactured in a form.

In the present invention, a crosslinkable vinyl compound having two or more vinyl groups in a molecule can be blended with the acrylic component. Specific examples of the crosslinkable vinyl compound include: ethylene glycol dimethacrylate, allyl acrylate, allyl methacrylate, divinylbenzene, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate,
6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, unsaturated polyester prepolymer derived from at least one kind of polycarboxylic acid including ethylenically unsaturated polycarboxylic acid and at least one kind of diol, etc. Is mentioned. Further, a radical polymerization initiator can be used to cure the polymerization raw material. As the radical polymerization initiator used here, it is preferable to use 0.001 to 5% by weight of a usual radical polymerization initiator based on the weight of the acrylic component. Specific examples include 2,2′-azobis (isobutyronitrile),
Azo compounds such as 2,2'-azobis (2,4-dimethylvaleronitrile), peroxyesters such as t-hexylperoxypivalate, t-butylperoxypivalate, t-butylperoxyneohexanoate Kind,
Organic peroxides such as benzoyl peroxide and lauroyl peroxide, and redox-based polymerization initiators thereof are examples of such initiators, and these can be used alone or in combination. When the polymerization initiator is an organic peroxide,
Tertiary amines can also be used as polymerization accelerators.
Further, for example, a hemi-ester of maleic acid obtained by reacting a saturated tertiary alkyl peroxymaleic acid such as t-butyl peroxymaleic acid with a basic metal compound, water, ethylene glycol dimercaptoacetate as a polymerization accelerator, A system in which a mercaptan compound such as the above, an oxoacid salt of sulfur or a sulfur activator which is a salt thereof, or the like can be used. These polymerization initiator systems can be appropriately selected depending on polymerization curing conditions (temperature, time, cost, etc.) desired by the manufacturer.

Further, in the present invention, in addition to the above-described components, various components conventionally known as additive components of the synthetic resin can be used. For example, white (titanium oxide,
Pigments such as zinc sulfide), yellow (iron oxide yellow), black (iron oxide black), red (iron oxide red), and blue (ultramarine blue, phthalocyanine blue), dyes, ultraviolet absorbers, flame retardants, mold release agents , Fluidizers, thickeners, polymerization inhibitors, antioxidants and the like.

When the method for producing a synthetic resin plate of the present invention is applied to the production of artificial marble, an acrylic artificial marble obtained by mixing a filler such as aluminum hydroxide, calcium carbonate, silica, etc. with the above-mentioned synthetic resin plate polymerization raw material. A plate polymerization raw material is used.

Examples of the filler include inorganic fillers such as calcium carbonate, alumina, glass fiber, aluminum hydroxide, silica, talc, magnesium hydroxide and calcium hydroxide, and resins and artificial marbles which are produced by crushing. Particle-type marble chips and the like, and acrylic component 100
It is preferable to use 10 to 400 parts by weight based on parts by weight. If the amount of filler is too low, it is difficult to obtain a marble-like texture and weight, and if it is too high, the transparency as artificial marble,
In some cases, the mechanical properties are deteriorated, making the material unsuitable as artificial marble.

As the inorganic filler, aluminum hydroxide is particularly preferably used. In the case of a stone-finished product, colored or uncolored particle-shaped marble chips are added thereto.

In the present invention, the surface of the inorganic filler may be treated with, for example, a silane coupling agent, a titanate coupling agent, a phosphoric acid coupling agent, or stearic acid. When the inorganic filler treated with these is used, the strength, heat resistance, weather resistance and hot water resistance of the artificial marble can be improved as compared with the untreated inorganic filler.

When the particle size of the inorganic filler is too large, the physical properties of the artificial marble are reduced. On the other hand, when the particle size is too small, the light transmittance of the artificial marble is reduced.
It is preferable to use one having a thickness of about 100 μm,
It is particularly preferable to use those having a size of about m. When a thermal polymerization initiator is used as a radical polymerization initiator for polymerization curing, the polymerization rate is lower than that of a redox initiator, and during that time, an inorganic filler having a large particle diameter tends to settle, which is not preferable. Use of a high white type having a hunter whiteness of at least 90%, preferably at least 95% as measured by a method according to JIS P8123 makes it possible to improve the color tone of the artificial marble product or to easily adjust the color tone. Is most preferred.

As the particle-shaped marble chips, colored or uncolored particles having a particle diameter range of 100 to 5000 μm obtained by crushing a resin or artificial marble in which an inorganic filler is dispersed in a resin are preferable. These are disclosed in JP-A-4-504402, JP-A-9-2857, and JP-A-9-1885.
As described in JP-A-56-56, etc., an appropriate amount is used within the above range according to a desired design. When the filler is mixed with the raw material for polymerization, silica having a primary particle diameter of 5 to 50 nm and a specific surface area of 50 to 400 m ² / g described in JP-A-3-285854 and JP-A-9-110498 is used. A method for preventing settling of the filler, such as adding 5 parts by weight or less of fine particles to 100 parts by weight of the polymerization raw material, can be adopted.

[0039]

The present invention will be described below with reference to examples and comparative examples. In these, “%” means weight%,
"Parts" means parts by weight.

Example 1 Methyl methacrylate syrup having a conversion of 20% (viscosity 1
(Pa · s, 20 ° C.) 100 parts, 0.005 part of dioctyl sulfosuccinate as a release agent, and t-hexyl peroxypivalate as a polymerization initiator (Nippon Oil & Fats Co., Ltd.)
(Trade name: Perhexyl PV) was added and uniformly mixed.

After the obtained polymerization raw material was defoamed in a vacuum vessel, a resin plate having a thickness of 3 mm was manufactured using the apparatus shown in FIG. The apparatus of FIG. 1 has a thickness of 1.5 mm and a width of 1500 mm.
The stainless steel endless belts are installed substantially horizontally, and only the lower belt is driven. As a belt surface holding mechanism in the first heating zone (13), a plurality of pairs of rollers (4) each axis of which is perpendicular to the belt running direction and supported by a shaft, and a spring (15) mounted on a frame (14) above the belt. ) Are arranged in the belt running direction, and 2.5 kPa in the frame (14-1), 1.5 kPa in the frame (14-2), and
In -3), the pressure is adjusted to give an average pressure of 1.0 kPa, and the resin plate is held by the roller groups (4) and (4 ') so as to have a uniform thickness of 3 mm. A polyethylene terephthalate film (manufactured by Teijin Limited) having a thickness of 50 μm and having a matte finish on one side after applying polyethylene glycol having a molecular weight of about 200 as an adhesive liquid on the surfaces of the two endless belts,
Using a method described in Japanese Patent Application Laid-Open No. 54-157166, the mat is attached so that the mat surface faces the polymer. As the gasket, a polyvinyl chloride gasket described in JP-B-47-49823 was used. The total length of the polymerization machine is 9
At 0 m, the first heating zone (13) 60 m at the front is heated by spraying hot water of 80 ° C. in a shower form from the outer surface of the belt,
The rear second heating zone (9) (9 ') 10m is 120 ° C
Heated in an air furnace. Belt running speed is 1.5
m / min.

The obtained acrylic synthetic resin plate had a mat-like surface, had no defects, and was excellent in design. The thickness accuracy was 3 ± 0.1 mm, which was good.

COMPARATIVE EXAMPLE 1 Except for using a polymerization apparatus without a spring (15) and applying no pressure to the synthetic resin plate polymerization raw material between the belts in the frames (14-1) to (14-3). An acrylic synthetic resin plate was manufactured in the same manner as in Example 1.

The obtained acrylic synthetic resin plate partially contained defects, and the thickness accuracy was 3 ± 0.5 mm.

Example 2 Using a 50 μm-thick polyvinyl alcohol film (manufactured by Tosello Co., Ltd.) with a matte finish on one side, four soft polyvinyl chloride gaskets were used. Using a double arrangement,
A synthetic resin plate was obtained in the same manner as in Example 1, except that the film was held by the inner gasket so as not to come out of the outer gasket. The width of the film is 1420 mm, the inner gasket is installed just inside both ends of the film, and the outer gasket is installed outside the belt at 20 mm from both ends of the belt. Although the film was water-soluble, no abnormality was found during the production of the synthetic resin plate because the outside gasket did not allow hot water to enter.

The obtained acrylic synthetic resin plate had a mat-like surface, had no defects, and was excellent in design. The thickness accuracy was 3 ± 0.1 mm, which was good.

Example 3 Methyl methacrylate having a polymerization rate of 20% (viscosity 1.
2 Pa · s, 20 ° C.) 70 parts, methyl methacrylate 29
Parts, 100 parts of a syrup mixed with 1 part of ethylene glycol dimethacrylate, 0.25 part of dioctyl sulfosuccinate as a release agent, and 1 part of alkyl acid phosphate (manufactured by DuPont, trade name: Zelek UN). Dissolved. While stirring the mixture with a mixer,
Silane-treated aluminum hydroxide powder having an average particle size of 8 μm and a Hunter brightness of 99% (Nippon Light Metal Co., Ltd.)
(Trade name: BW103ST), 150 parts was added little by little to obtain a slurry in which the aluminum hydroxide powder was uniformly mixed in the syrup. Thereafter, t-hexyl peroxypivalate (manufactured by NOF Corporation, trade name: Perhexyl PV) as a polymerization initiator for 250 parts of the slurry.
0.2 parts was added and uniformly mixed to obtain a polymerization raw material. 20
The viscosity of the raw material for polymerization at 1.4 ° C. was 1.4 Pa · s.

After degassing the obtained polymerization raw material in a vacuum vessel, an artificial marble plate having a thickness of 3 mm was manufactured using the apparatus shown in FIG. The apparatus of FIG. 1 has a thickness of 1.5 mm and a width of 1500 mm.
The two stainless steel endless belts are installed substantially horizontally, and only the lower belt is driven. As a belt surface holding mechanism in the first heating zone (13), a plurality of pairs of rollers (4) each axis of which is perpendicular to the belt running direction and supported by a shaft, and a spring (15) mounted on a frame (14) above the belt. ) Is disposed in the belt running direction, and the polymerization raw material between the belts is supplied with 2.5 kPa from the upstream side in the frame (14-1) at the frame (1).
1.5 kPa in 4-2), frame (14-3)
Is adjusted so as to give an average pressure of 1.0 kPa, and the artificial marble plate is held by the roller groups (4) and (4 ′) so as to have a uniform thickness of 3 mm. A polyethylene terephthalate film (manufactured by Teijin Limited) having a thickness of 50 μm and having a matte finish on one side after applying polyethylene glycol having a molecular weight of about 200 as an adhesive liquid on the surfaces of the two endless belts,
Using a method described in Japanese Patent Application Laid-Open No. 54-157166, the mat is attached so that the mat surface faces the polymer. As the gasket, a polyvinyl chloride gasket described in JP-B-47-49823 was used. The total length of the polymerization machine is 9
At 0 m, the first heating zone (13) 60 m at the front is heated by spraying hot water of 80 ° C. in a shower form from the outer surface of the belt,
The rear second heating zone (9) (9 ') 10m is 120 ° C
Heated in an air furnace. Belt running speed is 1.5
m / min.

The obtained acrylic artificial marble plate had a mat-like surface, had no defects, and was excellent in design. The thickness accuracy was 3 ± 0.1 mm, which was good.

Comparative Example 2 Example 3 was repeated except that no pressure was applied to the polymerization raw material between the belts in the frames (14-1) to (14-3) using a polymerization apparatus having no spring (15). In the same manner as in the above, an acrylic artificial marble plate was manufactured.

The obtained acrylic artificial marble plate partially contained defects, and the plate thickness accuracy was 3 ± 0.4 mm.

Example 4 Using a 50 μm-thick polyvinyl alcohol film (manufactured by Tosello Co., Ltd.) having a single-sided mat finish as the type of film attached to the endless belt, four soft polyvinyl chloride gaskets were used. Using a double arrangement,
An artificial marble plate was obtained in the same manner as in Example 3, except that the film was held down by the inner gasket so as not to come out of the outer gasket. The width of the film is 1420 mm, the inner gasket is installed just inside both ends of the film, and the outer gasket is installed outside the belt at 20 mm from both ends of the belt.
Although the film was water-soluble, there was no abnormality in the production of the artificial marble board because the outside gasket did not allow hot water to enter.

The obtained acrylic artificial marble plate had a mat-like surface, had no defects, and was excellent in design. The thickness accuracy was 3 ± 0.1 mm, which was good.

Example 5 Methyl methacrylate having a polymerization rate of 20% (viscosity 1.
To 100 parts of a syrup mixed with 99 parts of 2 Pa · s, 20 ° C.) and 1 part of ethylene glycol dimethacrylate, 0.17 parts of an alkyl acid phosphate (manufactured by DuPont, trade name: Zelek UN) was added as a release agent. Dissolved. While stirring the mixture with a mixer, an average particle size of 1
67 parts of aluminum hydroxide powder (trade name: BW153, manufactured by Nippon Light Metal Co., Ltd.) having a hunter brightness of 99% was added little by little to obtain a slurry in which the aluminum hydroxide powder was uniformly mixed in the syrup. Thereafter, to 167 parts of the slurry, 0.2 part of t-hexyl peroxypivalate (trade name: Perhexyl PV, manufactured by NOF CORPORATION) was added as a polymerization initiator and uniformly mixed to obtain a polymerization raw material. . The viscosity of the polymerization raw material at 20 ° C. is 2.7 Pa · s
Met.

An artificial marble plate was obtained in the same manner as in Example 3, except that the obtained polymerization raw material was defoamed in a vacuum vessel and used without attaching a film to an endless belt.

The obtained acrylic artificial marble plate had a smooth surface and the endless belt surface was transferred, and was excellent in design without defects. The thickness accuracy was 3 ± 0.1 mm, which was good.

[0057]

As described above, in the present invention,
A pair of endless belts facing each other are installed horizontally, one endless belt is driven by belt driving means, and the other endless belt is driven to follow the endless belt. 0.25 kPa for resin plate polymerization raw material
The above average pressure is applied. For this reason, it is possible to continuously produce a synthetic resin plate having a plate thickness accuracy not found in the prior art and free from bending, cracks, bubbles, dents and the like. The present invention, particularly in the continuous production of thin synthetic resin plates,
It is possible to provide a synthetic resin plate with dimensional accuracy and appearance in a region that cannot be achieved by the conventional technology.

Further, when the present invention is applied to the production of an acrylic artificial marble plate, an artificial marble plate having good design accuracy and excellent in design without bending, cracks, air bubbles, dents, etc. can be continuously produced. Can be produced.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for manufacturing a synthetic resin plate of the present invention.

[Explanation of symbols]

 1, 1 'endless belt 2, 2' rotating drum (front) 3, 3 'rotating drum (rear) 4, 4' roller group 5 metering pump for supplying polymerization raw material 6 raw material injection device 7, 7 'gasket 8, 8 'Hot water spray device 9, 9' Second heating zone 10, 11 Cooling zone 12 Synthetic resin plate 13 First heating zone 14-1, 2, 3 Frame 15 Spring 16 Motor for belt drive

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Suemura 20-1 Miyukicho, Otake City, Hiroshima Prefecture Inside Mitsubishi Rayon Co., Ltd. Central Research Laboratory (72) Inventor Koji Nishida 20-1 Miyukicho, Otake City, Hiroshima Prefecture No. F-term in Central Research Laboratory, Mitsubishi Rayon Co., Ltd. (reference) 4F204 AA21L AB04 AB11 AB12 AF09 AG02 AR02 FA11 FB02 FN11 FQ23 FQ38

Claims (6)

[Claims] 1. A pair of endless belts running opposite to each other, and a gasket disposed near both ends of the pair of endless belts and running following the running of the belts while being sandwiched between the pair of endless belts. In a synthetic resin plate manufacturing apparatus for continuously heating and polymerizing a synthetic resin plate polymerization raw material in a space formed by the facing surfaces of the pair of endless belts and the gasket, the pair of endless belts are substantially One of the pair of endless belts is driven by belt driving means, and the other belt is driven following the pair of endless belts. At least in the first half of the overlapping area, the pair of endless belts are driven. A pressure applying device for applying an average pressure of 0.25 kPa or more to the synthetic resin plate polymerization raw material interposed between the belts is provided. An apparatus for producing a synthetic resin plate. 2. The synthetic resin plate according to claim 1, wherein a film for providing a concavo-convex pattern on the synthetic resin plate is provided on at least one molding surface of the pair of endless belts. manufacturing device. 3. A pair of endless belts running opposite to each other, and a gasket disposed near both ends of the pair of endless belts and running following the running of the belt while being sandwiched between the pair of endless belts. Using a polymerization apparatus provided with, a synthetic resin plate manufacturing method of injecting a synthetic resin plate polymerization raw material into a space formed by the opposed surfaces of the pair of endless belts and the gasket and continuously heating and polymerizing, The pair of endless belts are installed substantially horizontally, and one of the pair of endless belts is driven by belt driving means and the other belt is driven following the pair of endless belts. Applying an average pressure of 0.25 kPa or more to the synthetic resin plate polymerization raw material interposed between the endless belts. Manufacturing method of a synthetic resin plate. 4. The production of a synthetic resin plate according to claim 3, wherein a film for providing an uneven pattern on the synthetic resin plate is provided on at least one molding surface of the pair of endless belts. Method. 5. The method for producing a synthetic resin plate according to claim 3, wherein the synthetic resin plate polymerization raw material is a methyl methacrylate-based partial polymer. 6. The synthetic resin plate is an acrylic artificial marble plate, and the synthetic resin plate polymerization raw material is an acrylic artificial marble plate polymerization raw material containing a filler. 3. The method for producing a synthetic resin plate according to item 1.