JPS6225489B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a decorated methacrylic resin board, more specifically, a decorated methacrylic resin board having a colored or printed polyalkyl methacrylate film near the surface is manufactured by casting polymerization. The present invention relates to a manufacturing method.

Methacrylic resin plates have high transparency, good surface gloss, and excellent weather resistance, chemical resistance, moldability, etc., and are used in various fields by taking advantage of these properties. Industrial methods for manufacturing this methacrylic resin plate include a method of cast polymerization using a template such as tempered glass, and an extrusion method of melting and extruding a molding material. Among these, the resin plate obtained by the former method has a higher degree of polymerization than the latter resin plate, has excellent chemical resistance and heat resistance, and has a good surface gloss, so this cast polymerization method is currently used. It has become the mainstream for manufacturing methacrylic resin sheets. By the way, methacrylic resin plates are available in two types: a colorless transparent plate that takes advantage of its transparency as described above, and a beautiful colored plate that is colored with various colorants. There is a regret that usually only a single color plate can be obtained because it is manufactured by adding .

There has been a demand for the use of methacrylic resin plates by forming a patterned or printed surface on their surface, but in such cases it is difficult to manufacture using the above-mentioned cast polymerization method, so a film printed during extrusion molding is used. Usually, a method is used in which a sheet is made by attaching a film to a resin plate, or a method is used in which a film is attached to a resin plate using heat or an adhesive. However, resin plates obtained by this method tend to have air bubbles at the boundary between the film and resin during heat molding, problems with the chemical resistance and hot water resistance of the molded product, and problems with beautiful surfaces. However, there has been a strong desire to industrially produce resin plates that solve these problems.

The present invention was made in view of the above circumstances, and its gist is to inject a methyl methacrylate partial polymer into opposed mold plates and polymerize and harden it to form a cast polymer plate of methacrylic resin. During manufacturing, a colored or printed polyalkyl methacrylate film is coated with a methyl methacrylate partial polymer on the inner surface of one or both templates, and then the colored or printed polyalkyl methacrylate film is bonded. At the same time, the applied methyl methacrylate partial polymer is solidified, and then the methyl methacrylate partial polymer is injected and polymerized and cured to integrally form a colored or printed polyalkyl methacrylate film near the surface of the methacrylic resin plate. A method for producing a decorated methacrylic resin plate, characterized in that the plate is bonded to a decorated methacrylic resin plate.

The present invention will be explained below with reference to drawings of examples. Figure 1 is a schematic diagram of an apparatus used in the manufacturing method of the present invention, and Figure 2 shows a state in which a polyalkyl methacrylate film is bonded to a template. A perspective view showing
FIG. 3 is a partial cross-sectional view of a methacrylic resin plate obtained by the present invention.

In FIG. 1, reference numerals 1 and 1 indicate a pair of opposed templates, which are usually made of tempered glass whose surface has been polished to a smooth surface. Reference numeral 4 designates a gasket for maintaining the distance between the templates 1 and 1 and preventing leakage of the methyl methacrylate partial polymer 3 injected between the templates, and is generally made of vinyl chloride resin. Reference numeral 5 denotes a fixing tool such as a vise, which presses the templates 1, 1 from the outside with the gasket 4 clamped around the periphery as shown.

A cast polymer plate of methacrylic resin is generally manufactured using an apparatus as shown in FIG. The methacrylate film 2 is coated with a methyl methacrylate partial polymer in advance, fixed and bonded. An example of a method of bonding the polyalkyl methacrylate film 2 to the template is shown in FIG. That is, one template 1 is placed on the group of carrier rolls 6 and moved in the direction of the arrow 9 at an appropriate speed. A storage tank 7 containing a methyl methacrylate partial polymer is installed at an appropriate position above the group of carrier rolls 6, and the methyl methacrylate partial polymer 3, which has been adjusted to a certain viscosity, is transferred from the storage tank 7 to the template 1. flow down onto the surface. A press roller 8 is installed in front of this, and just before this roller 8, a colored or printed polyalkyl methacrylate film 2 is placed.
are now being supplied. The template 1 coated with a thin film of the methyl methacrylate partial polymer 3 is sent to the press roller 8 , where the polyalkyl methacrylate film 2 is supplied onto the surface. It is pressed and the excess methyl methacrylate-based partial polymer 3 is squeezed out to form a thin, uniform film thickness. In the case of such a joining method, it is necessary to avoid slowing down the moving speed of the template too much. This is because the polyalkyl methacrylate film 2 easily swells and dissolves in the methyl methacrylate partial polymer 3, so when the polyalkyl methacrylate film 2 is pressed by the press roller 8, it remains in contact with the partial polymer 3 for a long time. This is because the film 2 may be damaged too much due to contact, and this portion may even be severed. It is also necessary to adjust the viscosity of the methyl methacrylate partial polymer and the coating thickness, but this is due to the tendency of the polyalkyl methacrylate film 2 to easily swell and dissolve in the methyl methacrylate partial polymer 3, as described above. If this adjustment is incorrect, the film may become wrinkled or the printed surface may be stained. Naturally, the film thickness of the methyl methacrylate-based partial polymer can be controlled by the hardness of the press roller 8 and the press pressure.

The template 1 with the polyalkyl methacrylate film 2 bonded to its inner surface as described above is then left to stand naturally or, if necessary, heated with an infrared lamp or the like to sufficiently dry and solidify the methyl methacrylate partial polymer 3. let

Using the template 1 to which the colored or printed polyalkyl methacrylate film 2 has been bonded in advance, the methyl methacrylate partial polymer 3 is poured into the assembled mold as shown in FIG.
This is heated in an air bath or water bath to polymerize and harden, similar to the general cast polymerization method. In addition, when manufacturing a methacrylic resin plate having polyalkyl methacrylate films bonded to both sides, prepare two templates with the above films bonded to the inner surfaces in advance as shown in FIG.
A resin plate may be manufactured by placing them oppositely in the same manner as shown in the figure and casting and polymerizing them in the same manner. The methacrylic resin plate thus obtained is beautiful in that a colored or printed polyalkyl methacrylate film 2 is integrally bonded near the surface as shown in FIG. As mentioned above, the polyalkyl methacrylate film 2 has the property of being easily swollen or dissolved by the methyl methacrylate partial polymer 3, and when cast polymerized and cured as described above, it becomes extremely strong and integral. It can be joined to. In particular, since polymerization is carried out by casting using a template, a resin plate with good surface smoothness is obtained by directly transferring the smooth surface of the template, and even if the resin plate is subsequently heat-formed, no air bubbles will occur. Moreover, it is possible to provide a resin plate that has excellent chemical resistance and hot water resistance. In addition, since the polyalkyl methacrylate film is bonded to the inner surface of the template in advance and then cast and polymerized, shrinkage and wrinkles of the film can be prevented, and the printed surface of the film can be manufactured without staining. I can do it.

The decorated methacrylic resin plate manufactured according to the present invention is not substantially different from a single resin plate obtained by casting polymerization, and therefore the methyl methacrylate partial polymer 3 used is
is not particularly different from the general one.

The polyalkyl methacrylate film 2 used in the present invention is mainly made of methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, etc., and if necessary, other acrylates, vinyl acetate, vinyl chloride, styrene, acrylonitrile, methacrylonitrile, etc. A homopolymer or copolymer obtained by polymerizing these as a comonomer component is obtained in the form of a film by a normal extrusion method, and its thickness is not particularly limited, but If wrinkles are likely to occur during the printing process, it is recommended to use a material of 50μ or more. The polyalkyl methacrylate film thus obtained is colored in an arbitrary color at the time of film production, or is suitably printed by a known printing method after it is made into a film.

Specific examples will be described below, but it goes without saying that the present invention is not limited to these examples.

Example 1 <Joining of film to template> Bonding was carried out using an apparatus as shown in FIG. 2. That is, a template made of tempered glass with a smooth polished surface was placed on the carrier roll group, and was moved at a speed of 2.4 m/min. The storage tank has a viscosity
Fill the methyl methacrylate-based partial polymer adjusted to 50 cps, attach a gauze cloth to the bottom of the storage tank, allow the partial polymer to drip through the gauze, and pour the partial polymer onto the moving template. It was applied thinly. Next, move the template to the press roller and make a 75μ thick sheet with printing on one side.
The bonding was carried out while supplying a polyalkyl methacrylate film. The press roller at this time is
Made of neoprene rubber with a hardness of 40 degrees,
The roller pressure was 0.2 Kg/cm ² .

Once the template has passed the press roller, the polyalkyl methacrylate film is cut,
When this was air-dried, part of the methyl methacrylate monomer in the methyl methacrylate-based partial polymerized product evaporated, and part of it was polymerized and solidified into a template together with the polyalkyl methacrylate-based film. In this case, the film thickness of the methyl methacrylate partial polymer after solidification was about 7 μm.

<Manufacture of resin plate> A resin plate was manufactured using the apparatus shown in FIG. 1 using a template to which a polyalkyl methacrylate film was bonded by the method described above. The size of the template at this time is 1320mm x 1930mm, with a spacing of 2mm between the templates.
I assembled it to look like this. Next, a methyl methacrylate partial polymer with a viscosity of 200 cps was injected into this template, and it was immersed in a 65°C hot water bath for 2 hours to polymerize, and then heated in a high-temperature air bath at 125°C for 1 hour.
Polymerization was completed by treatment for a period of time. When the resin plate was removed from the mold after cooling, a beautiful methacrylic resin plate with a polyalkyl methacrylate film uniformly and firmly bonded near one surface was obtained.

The methacrylic resin plate obtained by the present invention
When heated at 180°C and vacuum formed using a mold with a diameter-to-height ratio of 1:07 according to conventional methods, no defects such as interfacial peeling or film cracks occurred. In addition, when a resin plate was placed in contact with a rod heater (heater surface temperature: 130°C) to locally heat the plate and bent to form an acute angle on the inner surface, defects occurred as in the case of vacuum forming. Nakatsuta.

Further, hot water is prepared by immersing the methacrylic resin plate obtained according to the present invention in hot water at 95°C for 7 hours and leaving it in a drying oven at 80°C for 16 hours.
When a drying cycle test was carried out, even after 12 cycles, there was no peeling or cracking, and no defects such as cloudiness occurred.

Example 2 <Joining of film to template> This was carried out using the same apparatus as in Example 1 and using the same type of template. The size of the template is 1000mm.
It was x2000mm. The moving speed of the template was 1.0 m/min, and the methyl methacrylate partial polymer used had a viscosity of 500 cps. A press roller made of NBR with a hardness of 50 degrees was used, and the same polyalkyl methacrylate film as in Example 1 was bonded at a pressure of 0.94 Kg/cm ² . The printed polyalkyl methacrylate film was bonded to the surface of the template as described above, and the film thickness of the methyl methacrylate partial polymer at this time was approximately 10 μm.

<Manufacture of resin plate> Using the template to which the film was bonded, obtained as described above, a mold as shown in FIG. 1 was assembled in the same manner as in Example 1. After injecting a methyl methacrylate partial polymer with a viscosity of 250 cps into this template,
After being immersed in a hot water bath at 125°C for 2 hours, it was further treated in a high-temperature air bath at 125°C for 2 hours to polymerize and harden.

The obtained resin plate was of good quality as in Example 1.

Example 3 <Joining the film to the template> Using the same device as in Example 1, the size was 1000 mm.
It was carried out using a template of ×2000mm. The moving speed of the template was 0.5 m/min, and the methyl methacrylate partial polymer used had a viscosity of 200 cps. The press roller was made of polyurethane foam with a load of 15 g/cm ² required for 25% compression, and the same polyalkyl methacrylate film as in Example 1 was bonded at a pressure of 0.15 kg/cm ² . . The printed polyalkyl methacrylate film was bonded to the surface of the template as described above, and the film thickness of the methyl methacrylate partial polymer at this time was about 90 μm. In this example, in order to solidify the partial polymer to which the films were bonded, heating was performed using an infrared lamp to promote evaporation and polymerization solidification of the partial polymer.

<Manufacture of resin plate> A methacrylic resin plate was manufactured using the template obtained as described above and in the same manner as in Example 2.

The obtained methacrylic resin plates were used in Examples 1 and 2.
Similarly, it was a beautiful product with a polyalkyl methacrylate film integrally bonded near the surface.

Since the present invention has the configuration as described in detail above, it is possible to industrially produce a decorated methacrylic resin plate by a cast polymerization method without requiring particularly high temperature or pressure conditions. In addition, the resulting resin board has the unique advantages of cast-polymerized boards, and the polyalkyl methacrylate film on the surface is firmly integrated, giving it an excellent wrinkle-free appearance. It has the advantage that it can be used for various purposes by being molded or heated.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an apparatus showing an embodiment of the manufacturing method of the present invention, Fig. 2 is a perspective view showing a state in which a polyalkyl methacrylate film is bonded to a template, and Fig. 3 is a schematic diagram of an apparatus showing an embodiment of the manufacturing method of the present invention. FIG. 3 is a partial cross-sectional view of the methacrylic resin plate thus obtained. 1, 1... template, 2... polyalkyl methacrylate film, 3... methyl methacrylate partial polymer, 4... gasket.

Claims (1)

[Claims] 1. When manufacturing a cast polymer board of methacrylic resin by injecting a methyl methacrylate-based partial polymer into opposing templates and polymerizing and curing it, the methyl methacrylate-based partial polymer is injected into the inner surface of one or both templates in advance. After coating, a colored or printed polyalkyl methacrylate film is bonded, and the applied methyl methacrylate partial resin polymer is solidified, and then the methyl methacrylate partial resin polymer is injected and polymerized and hardened. A method for manufacturing a decorated methacrylic resin board, characterized by integrally bonding a colored or printed polyalkyl methacrylate film near the surface of the methacrylic resin board.