JP2004181709A - Resin molded product and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the thermal deformation of a surface layer in a resin molded product of which the surface layer comprises a thermoplastic resin and the backup layer on a rear surface side comprises a resin concrete. <P>SOLUTION: An FRP layer is laminated on the rear surface of the surface layer comprising a thermoplastic resin and the backup layer comprising the resin concrete is provided on the FRP layer by a casting method. In order to enhance the bonding property of the surface layer and the FRP layer, primer treatment may be applied to the rear surface of the surface layer or a decorative layer using a transparent resin/colored resin/pattern material-mixed resin may be provided between the surface layer and the FRP layer. The transfer of heat generated at the time of curing of the resin concrete to the surface layer is prevented by forming the FRP layer between the surface layer and the backup layer to prevent the thermal deformation of the surface layer. Since the FRP layer has high strength, the wall thickness of the product can be made thin. Since the wall thickness of the product becomes constant and the outer surface of the backup layer is made smooth, piping or the like is easily attached in a watertight state and the danger of a water leak can be reduced markedly. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a resin molded product such as a bathtub, wherein a surface layer is formed of a thermoplastic resin such as acrylic.
[0002]
[Prior art]
Patent Literature 1 describes a resin molded product in which a surface layer is made of a thermoplastic resin such as an acrylic resin and a back layer on the back side is made of artificial marble, that is, resin concrete. Patent Document 1 describes the following manufacturing method for manufacturing the resin molded article. First, a thermoplastic sheet material heated to a predetermined temperature is attached to a mold, and the sheet material is deformed by a vacuum forming method to form a surface layer having a predetermined shape. Next, after this surface layer is cooled and hardened, it is detached from the mold and attached to an auxiliary mold separately prepared. Subsequently, a back mold material is disposed so as to cover the surface layer, and a closed space is formed between the back mold material and the surface layer. Then, an artificial marble material (resin concrete) is injected into the back mold material to fill the closed space. . Thereafter, when the artificial marble material is cured by being left for a predetermined period of time, it is released from the mold to obtain a desired resin molded product.
[0003]
Patent Document 1 also describes that an FRP layer is provided on the back side of the artificial marble layer. In this case, the FRP layer is provided in advance on the inner surface of the back mold material disposed on the surface layer, and the FRP layer is integrated by injecting and filling the artificial marble material into the closed space. Furthermore, it describes that after forming the surface layer, a transparent resin layer is provided between the surface layer and the artificial marble layer by spraying an unsaturated polyester resin or the like on the back surface. Also, there is a description that a glass flake or an aluminum foil plated with gold, silver, or the like is mixed in a transparent resin layer to enhance decorativeness.
[0004]
[Patent Document 1]
JP-A-7-68567
[Problems to be solved by the invention]
The resin molded product described in Patent Document 1 has an artificial marble layer directly provided on the back surface side of a surface layer made of a thermoplastic resin. However, resin concrete for forming an artificial marble layer may generate a relatively high temperature of about 120 ° C. due to the heat of hardening. By the way, the thermoplastic resin forming the surface layer is softened at about 80 ° C. in the case of, for example, an acrylic resin. For this reason, when casting the artificial marble layer on the back surface of the previously formed surface layer, the surface layer may be deformed by the heat generated by the resin concrete. The transparent resin layer provided between the surface layer and the artificial marble layer was extremely thin (about 0.3 mm) and did not have a function of preventing heat conduction to the surface layer.
[0006]
[Means for Solving the Problems]
The present invention is characterized by a resin molded product (hereinafter, referred to as the molded product of the present invention) adopted to solve the above-mentioned problem. The surface layer is made of a thermoplastic resin, and the back layer on the back side is made of resin concrete. And a FRP layer is formed between the surface layer and the backup layer. With this configuration, the FRP layer insulates the heat generated when the resin concrete forming the backup layer is hardened to the surface layer, so that the surface layer made of the thermoplastic resin is thermally deformed. Can be prevented. In addition, since the FRP layer generally has higher strength than resin concrete, the entire thickness can be reduced to obtain a product having the required strength. The thickness of the FRP layer is desirably in the range of 1 to 10 mm.
[0007]
In order to manufacture the molded article of the present invention, an FRP layer is laminated using a reinforcing fiber material and a synthetic resin on the back side of a surface layer molded into a predetermined shape using a thermoplastic resin. Is covered with a casting mold to form a closed space between the FRP layer and the casting mold, and a resin concrete material is injected into the closed space to provide a backup layer on the back side of the FRP layer. A method can be adopted. By adopting this method, the thickness of the product can be made constant and the outer surface of the backup layer can be made smooth, so that it is easy to install pipes and the like in a watertight manner, and the risk of water leakage is significantly reduced. Can be obtained.
[0008]
In addition, in order to improve the bondability between the surface layer and the FRP layer, it is preferable to apply a primer treatment to the back surface side of the surface layer and then laminate the FRP layer using a reinforcing fiber material and a synthetic resin.
[0009]
Further, a decorating layer may be provided between the surface layer and the FRP layer using a transparent resin, a colored resin, or a resin mixed with a pattern material.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An example of a method for manufacturing a resin molded product such as a bathtub according to the present invention will be described with reference to the drawings. The present invention is not limited to bathtubs, but also includes counterparts such as washbasins and kitchen counters, washbasins, washbasins, waterproof pans, storage shelves, bathtub aprons, interior wall panels, and other resin molded products that require design. Can be applied.
[0011]
First, as shown in FIG. 1 (A), a thermoplastic resin sheet S heated to a predetermined temperature is placed in a vacuum forming machine 10 so that an inner space 12 surrounded by a molding surface 11 and the resin sheet S is in an airtight state. Set so that
[0012]
A typical example of the thermoplastic resin used is an acrylic resin. When an acrylic resin is used, the heating temperature of the resin sheet S is preferably set to about 140 ° C.
[0013]
Subsequently, as shown in FIG. 1B, the internal space 12 is degassed by using an exhaust means (not shown) such as a vacuum pump connected to the vacuum forming machine 10. As a result, the heated and softened resin sheet S is sucked and deformed as shown in the figure, and then comes into close contact with the molding surface 11 as shown in FIG. Thereafter, if the resin sheet S is left to cool and solidify, and then removed from the mold, the surface layer 1 made of a thermoplastic resin is obtained.
[0014]
Next, an FRP layer is formed on the back surface side of the surface layer 1. Before that, it is desirable to form a decorative layer or a primer layer on the back surface of the surface layer 1. That is, a decorative resin material is sprayed on the back surface of the surface layer 1 using the spray gun 13 or the like to form the decorative layer 4 as shown in FIG. 2B and FIG. 5B. As the resin material used at this time, an unsaturated polyester resin may be used, and this may be used as it is colorless and transparent.However, it is also possible to add a pigment for coloring or mix an appropriate pattern material. is there. The shape of the pattern material may be granular, flaky, flaky, etc., and the material may be mineral materials such as mica or natural stone, metallic materials such as aluminum, copper, silver, gold, acrylic, polyethylene, or the like. Organic materials such as polyvinyl chloride / polyamide / polycarbonate / polyethylene terephthalate (PET), metal-plated glass flakes and the like are conceivable.
[0015]
Instead of the decorative layer 4, a primer treatment may be performed on the back surface of the surface layer 1 to provide a primer layer 5 as shown in FIG. 6 (B) to improve the bonding property of the FRP layer. Examples of the primer treatment material include methylene dichloride and a mixture of methyl methacrylate and an unsaturated polyester resin.
[0016]
When the decorative layer 4 or the primer layer 5 is provided as necessary as described above, the formation of the FRP layer is subsequently performed. According to the spray-up method, for example, as shown in FIG. 2B, a glass fiber (chopped strand glass) cut with a synthetic resin is sprayed using a spray gun 14 or the like. In the case of using the hand lay-up method, a chopped strand glass mat may be attached while impregnated with a synthetic resin. Thereafter, the FRP layer 2 as shown in FIGS. 2 (C), 5 (C), and 6 (C) is provided on the back surface side of the surface layer 1 by performing a heat treatment and curing. be able to. The synthetic resin used for the FRP layer 2 is generally an unsaturated polyester resin or a urethane resin, and a coloring agent such as a pigment may be blended if desired.
[0017]
Note that the thickness of the FRP layer is preferably about 1 to 10 mm. If the thickness is less than 1 mm, the strength of the product may be insufficient. On the other hand, when the thickness exceeds 10 mm, the material cost increases, and the weight becomes too large, which may make it difficult to handle the product.
[0018]
Next, a backup layer 3 made of resin concrete is formed on the back surface of the FRP layer 2 by a casting method as shown in FIGS. 3 and 4. Resin concrete is a mixture of synthetic resin such as unsaturated polyester and filler such as glass powder, glass frit, aluminum hydroxide, calcium carbonate, pulverized natural stone, etc. It may be added.
[0019]
The molded article provided with the FRP layer 2 on the back surface side of the surface layer 1 as described above is placed on the support die 15 shown in FIG. 3A, and is further placed thereon as shown in FIG. As shown, the casting mold 16 is covered, and a closed space 17 is formed between the FRP layer 2 and the casting mold 16. Then, as shown in FIG. 4, resin concrete is poured from the pouring portion 18 of the casting mold 16 to the extent that it overflows from the overflow portion 19, and the closed space 17 is filled. Thereafter, the resin concrete is cured by heating as necessary.
[0020]
By the way, the resin concrete generates heat at the time of hardening, but in the present invention, the FRP layer 2 provided between the surface layer 1 and the backup layer 3 acts as a heat insulating layer to suppress the transfer of heat to the surface layer 1. Therefore, there is no fear that the surface layer 1 made of a thermoplastic resin is thermally deformed. After the curing of the resin concrete is completed, the molded article is released from the mold, and as shown in FIG. 5 (D) or FIG. 6 (D), the resin in which the backup layer 3 made of the resin concrete is formed on the back surface of the FRP layer 2 A molded article can be obtained. The thickness of the backup layer 3 is set to about 6 to 10 mm, and may be increased or decreased according to the thickness of the FRP layer 2.
[0021]
Since the molded article of the present invention has the high strength FRP layer 2 provided in the middle, even if the thickness of the backup layer 3 is reduced, the same strength as the conventional one can be secured. Therefore, the weight of the product can be reduced. Further, since the backup layer 3 is formed by cast molding of resin concrete, the outer surface is smooth and the thickness of the product can be made constant. Therefore, for example, in a bathtub manufactured according to the present invention, it is easy to install pipes and the like in a watertight manner without processing the outer surface.
[0022]
【The invention's effect】
According to the present invention, the heat generated during curing of the resin concrete is prevented from being transmitted to the surface layer by the FRP layer provided between the surface layer made of the thermoplastic resin and the backup layer made of the resin concrete. Accordingly, thermal deformation of the surface layer can be prevented. Therefore, a beautiful resin product having a surface layer formed of an acrylic resin or the like can be provided. Since the FRP layer improves the product strength, it can be made thinner, which results in a lighter product and a lower material cost.
[Brief description of the drawings]
FIG. 1 relates to an embodiment of a method for producing a molded article of the present invention, in which FIG. 1A is a front sectional view showing a state where a thermoplastic resin sheet is set in a vacuum molding machine, and FIG. FIG. 3C is a front cross-sectional view showing a state in which the resin sheet is being deformed by evacuating the internal space of the vacuum forming machine, and FIG. 1C is a front cross-sectional view showing a state in which a surface layer is formed.
FIG. 2 relates to an embodiment of a method for producing a molded article of the present invention, and FIG. 2 (A) is a front sectional view showing a state in which a decoration treatment or a primer treatment is performed on the back surface of a surface layer. (B) is a front sectional view showing a situation where the FRP material is sprayed on the back surface side of the surface layer, and FIG. (C) is a front sectional view showing a state where the FRP layer is formed on the back surface side of the surface layer.
FIG. 3 relates to an embodiment of a method for producing a molded article of the present invention, and FIG. 3 (A) shows a molded article having an FRP layer formed on the back surface of a surface layer, a supporting mold, and a casting mold. FIG. 2B is a front sectional view showing the mold in a disassembled state, and FIG. It is sectional drawing.
FIG. 4 relates to one embodiment of a method for producing a molded article of the present invention, and is a front sectional view showing a state in which resin concrete is poured into a closed space formed between a casting mold and an FRP layer. It is.
5 (A) is a front sectional view of a surface layer, and FIG. 5 (B) is a state in which a decorative layer is formed on the back surface of the surface layer. (C) is a front sectional view showing a state in which an FRP layer is formed, and FIG. (D) is a front sectional view showing a state in which a backup layer made of resin concrete is formed.
6 (A) is a front sectional view of a surface layer, and FIG. 6 (B) is a diagram showing a primer layer on a back surface of the surface layer. FIG. 4C is a front sectional view showing a state in which an FRP layer is formed, and FIG. 4D is a front sectional view showing a state in which a backup layer made of resin concrete is formed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Surface layer 2 ... FRP layer 3 ... Backup layer 4 ... Decorative layer 5 ... Primer layer

Claims (5)

A resin molded product in which a surface layer is made of a thermoplastic resin and a backup layer on the back side is made of resin concrete, wherein an FRP layer is formed between the surface layer and the backup layer. . The resin molded product according to claim 1, wherein the FRP layer has a thickness of 1 to 10 mm. The resin molded product according to claim 1, wherein a decorative layer made of a transparent resin, a colored resin, or a resin mixed with a pattern material is provided between the surface layer and the FRP layer. An FRP layer is laminated on the back side of the front surface layer molded into a predetermined shape using a thermoplastic resin, and the FRP layer is covered with a casting mold and closed between the FRP layer and the casting mold. A method for producing a resin molded product, comprising forming a space, injecting a resin concrete material into the closed space, and providing a backup layer on the back side of the FRP layer. The method for producing a resin molded product according to claim 4, wherein after performing a primer treatment on the back surface side of the surface layer, an FRP layer is laminated.

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