JPH11291333A - Production of bathtub made of resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more inexpensively manufacture a resin bathtub having various designs while reducing the cost related to a mold. SOLUTION: In a resin bathtub manufacturing method performing a molding process by attaching a detachable mold part 2 for forming the shape of a part such as an armrest, a seat an anti-skid element to a fundamental thermoforming mold 1 or detaching the same from the mold corresponding to the shape of a bathtub to be manufactured, the molding process performing the operation for attaching or detaching the mold part 2 is, for example, a process for performing the vacuum molding or pressure forming of a thermoplastic resin panel to obtain a thermoplastic resin molded product B constituting the surface layer of the bathtub and/or an FRP laminate molding process for placing the molded thermoplastic resin molded product B and a fiber reinforcing material with in a mold and injecting a polymerizable and curable resin raw material into the molding polymerize and cure the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin bathtub, for example, in which a thermoplastic resin molded product previously formed into a bathtub shape is reinforced with a fiber-reinforced polymerization-cured resin or the like.

[0002]

2. Description of the Related Art Conventionally, a thermoplastic resin such as an acrylic resin has been used as a surface layer, and a fiber-reinforced polymerized and cured resin (hereinafter, referred to as "reverse") has been used from the back.
Products such as bathtubs and washbasins reinforced with FRP) are on the market. As a manufacturing method, a method is generally used in which a thermoplastic resin plate is stretch-formed by vacuum forming, pressure forming, or the like, and reinforced with FRP from the back of the thermoplastic resin molded product.

In such products, FRP is used to reinforce a thermoplastic resin molded article. In the thermoplastic resin molded product, a portion having a small thickness tends to be formed by the molding, and the strength of the portion at the time of use is insufficient. The use of thermoplastic resin molded products at high temperatures is limited.

In Japanese Patent Application Laid-Open Nos. 51-91965 and 5-237854, a thermoplastic resin molded product is used in one of the molds, and a cell is formed by combining the mold with the other mold. A method is disclosed in which a curable resin material is injected, polymerized and cured, and integrated with a thermoplastic resin molded product. According to this method, the thermoplastic resin molded product is
There is no need to perform defoaming work when reinforcing with RP,
Work environment is not impaired.

[0005]

[Problems to be solved by the invention] In the design of the bathtub,
There are many things that can be said to be almost the same shape, such as armrests, stools, non-slip, etc., except for some shapes. Heretofore, even in such a bathtub having substantially the same shape, a separate dedicated mold has been used for each design. Therefore, a large number of molds are required, the cost of the molds is increased, the time required for exchanging the molds is large, a large space is required for storing the molds, and the production cost of each bathtub is increased.

Further, even if the bathtubs have substantially the same shape,
In the case of a bathtub having a shape expected to be produced in a small amount, there is a case where production has to be stopped from the viewpoint of cost, and it has not been possible to satisfy various demands of consumers.

That is, the object of the present invention is to provide, for example,
It is an object of the present invention to provide a method capable of reducing costs related to a mold, such as occupation / replacement time and storage location, and manufacturing resin baths of various designs at lower cost.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a resin bathtub which includes a molding step using a mold having a shape corresponding to the shape of a bathtub to be manufactured. The method can be attained by a method of manufacturing a resin bathtub in which parts are detachable and the molding step is performed by attaching or detaching the mold parts according to the shape of the bathtub to be manufactured.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a typical example of the manufacturing method of the present invention, (1) First, a thermoplastic resin plate such as an acrylic resin plate is vacuum-formed or pressure-formed to form a surface layer of a bathtub. Vacuum forming or pressure forming step for obtaining a thermoplastic resin molded article having a shape; (2) Next, at least the thermoplastic resin molded article obtained in the above step (1) and a fiber reinforcing material are placed in a mold; A method for producing a resin bathtub, comprising: an FRP lamination molding step of injecting a polymerization-curable resin material into the mold and polymerizing and curing the same, thereby reinforcing the back surface of the thermoplastic resin molded article with FRP.

In the present invention, the operation of attaching or detaching the detachable mold part according to the shape of the bathtub may be performed in at least one of the steps (1) and (2). However, it is more preferable to perform this operation in both steps (1) and (2) in terms of cost and the like.

In the following description, an embodiment will be described in which the operation of attaching or detaching a detachable mold part is performed in both steps (1) and (2).

1 to 4 are schematic sectional views showing one embodiment of the manufacturing method of the present invention.

First, as shown in FIGS. 1 and 2, a thermoforming mold 1 (and a detachable mold part 2), which is a female mold for vacuum forming or pressure forming, is used to form a thermoplastic resin having a desired thickness. By vacuum forming or pressure forming the resin plate, a thermoplastic resin molded product A or B having a shape corresponding to the shape of the bathtub to be manufactured (the shape of the surface layer) is formed.

The example shown in FIG. 1 is an example in the case of molding without attaching a detachable mold part, and a thermoplastic resin molded product A having a shape corresponding to a basic bathtub shape is obtained. On the other hand, the example shown in FIG.
The basic shape is the same as that of the thermoplastic resin molded product A, but the thermoplastic resin is further provided with a shape such as an armrest, a stool, and a non-slip by the mold part 2. Resin molding B is obtained.

As described above, when two types of thermoplastic resin molded products A and B, which can be said to be almost the same shape only with a partly different shape such as an armrest, a stool, a non-slip, etc. By simply attaching or detaching the basic thermoforming mold 1, the basic thermoforming mold 1 can be used in common. That is, in this example, when performing vacuum forming or pressure forming, even a bathtub having a partially different shape can be handled by a set of molds (the thermoforming mold 1 and the mold part 2).

The shape of the detachable mold part 2 depends on a partial shape provided in the bathtub as required, such as an armrest, a seat, or a non-slip, among the shapes corresponding to the shape of the bathtub (the shape of the surface layer). It may be designed, and there is no specific limitation on the shape of the removable mold part 2 in the present invention. 1 and 2, a mold part 2 detachable from the thermoforming mold 1 is shown.
When the is removed, it constitutes a basic flat surface (Fig. 1),
Although an example in which a desired convex portion is formed by the mold component 2 when the detachable mold component 2 is attached (FIG. 2) has been described,
The present invention is not limited to this. For example, conversely, when the detachable mold component 2 is attached, a basic flat surface is formed, and when the detachable mold component 2 is removed, a desired convex portion (or concave portion) or the like appears. A configuration may be adopted.

The thermoplastic resin plate used to obtain the thermoplastic resin molded products A and B is, for example, an acrylic resin plate, a polystyrene plate, an ABS resin plate or a laminate thereof, which can be formed by vacuum forming or pressure forming. Various resin plates can be used. Further, auxiliary molding using a plug or the like may be performed. The thermoplastic resin plate may be printed or a film may be laminated, and furthermore, a patterning with a gel coat resin is possible.

In particular, it is preferable to use an acrylic resin plate having excellent thermoforming processability and solvent resistance as the thermoplastic resin plate. As this preferred acrylic resin plate,
For example, as described in Japanese Patent Publication No. 6-70098,
When producing an acrylic resin plate by polymerizing methyl methacrylate alone or a monomer mixture of methyl methacrylate 60% by weight or more and acrylic ester 40% by weight or less in the presence of a polymerization initiator, A syrup is prepared by adding 0.01 to 20% by weight of a chain transfer agent, based on the whole monomer, and then 0.02 to
An acrylic resin plate obtained by adding 1.0% by weight of a crosslinking agent and performing casting polymerization in a mold is exemplified.

Examples of the thermoforming mold 1 include a wooden mold using hardwood such as Himekomatsu, Sakura and Hinoki, and an FRP using epoxy resin, vinyl ester resin, unsaturated polyester resin and the like.
, A mold composed of a laminate of FRP and resin concrete, a Ni electroformed mold (FRP coated with nickel), a mold composed of metal such as aluminum, and reinforced with a rib structure Various types of dies, such as dies, which are conventionally known to be usable for vacuum forming or pressure forming can be used without limitation. Also, the removable mold part 2 can be made of the same material as the thermoforming mold 1.

When the removable mold part 2 is attached to the bottom of the female thermoforming mold 1 as shown in FIG. 2, it is not always necessary to fix the mold part 2 to the thermoforming mold 1. , Just rest on the bottom. On the other hand, when attaching the detachable mold part 2 to the side surface of the thermoforming mold 1 or the like,
This needs to be fixed. In this case, for example, a hole is provided in the thermoforming mold 1, a corresponding pin is provided in the detachable mold part 2, and a pin of the detachable mold part 2 is inserted into the hole of the thermoforming mold 1. Just fix it. As shown in FIG. 1, when vacuum forming or pressure forming is performed with the detachable mold part 2 removed, the fixing holes provided in the thermoforming mold 1 may be pins or the like fitted into the holes. It should be closed with.
Furthermore, opening a vacuum hole in the removable mold part 2 requires
This is effective in improving the close contact with the thermoforming die 1.

Next, as shown in FIG. 3 and FIG.
Among the molds for lamination molding (male mold 3 and female mold 4), the male mold 3 side is placed so as to cover the previously molded thermoplastic resin molded product A or B, and a reinforcing layer is further formed thereon. The male mold 3 and the female mold 4 are combined by placing a fiber reinforcing material or the like for constituting 5. In this manner, the thermoplastic resin molded product A or B and the fiber reinforcing material, etc., are placed inside the mold. Is injected and filled, then polymerized and cured to be integrated with the thermoplastic resin molded product A or B. If the integrated laminated product is removed from the mold, a resin bath with the thermoplastic resin molded product A or B as the surface layer and the back surface thereof reinforced with FRP can be obtained. Such FRP lamination molding is suitably applied particularly for reinforcing a thin thermoplastic resin molded product.

In the female mold 4 for the FRP lamination molding, a certain space is formed between the female mold 4 and the thermoplastic resin molded product A or B placed on the male mold 3 to form a space. This spacing determines the thickness of the reinforcing layer 5.
The spaces at regular intervals are formed as closed spaces (cells) in which a reinforcing material such as a fiber reinforcing material is provided and in which a polymerization curable resin can be injected and cured. In order to form this sealed cell, for example, the peripheral edge of the thermoplastic resin molded product A or B and the peripheral edge of the female mold 4 may be clamped, and sealed with a seal packing, a clamp, or the like. Here, as a peripheral portion of the thermoplastic resin molded product A or B, for example,
In the previous vacuum forming or pressure forming, the thermoplastic resin plate A
Alternatively, a portion corresponding to a clamp margin for holding a thermoplastic resin plate when B is formed can be used. Note that this mold clamping is performed so as not to pinch a fiber-reinforced reinforcing material or the like placed inside in advance.

The example shown in FIG. 3 is an example in which a detachable mold part 7 is attached to the male mold 3 and molded, and the thermoplastic resin molded article A molded in the step shown in FIG. hand,
This is an example of manufacturing a resin bath having a basic shape. on the other hand,
The example shown in FIG. 4 is an example in which the detachable mold part 8 is attached to the female mold 4 and molded, and the thermoplastic resin molded article B molded in the step shown in FIG. This is an example of manufacturing a resin bathtub to which shapes such as an armrest, a stool, and a non-slip are added.

As described above, when two types of resin bathtubs which can be said to have almost the same shape except for a part of the shape of the armrest, the stool, the anti-slip, etc. are formed by FRP lamination, the detachable mold parts 7 or 8 are formed. The basic male mold 3 and female mold 4 can be used in common simply by attaching or detaching.
That is, in this example, in performing the FRP lamination molding, even if the bathtubs are partially different in shape, a set of molds (male mold 3, female mold 4, and detachable mold parts 7 or 8) is used. It is possible to respond.

The shape of the detachable mold part 7 or 8 is the same as the shape of the thermoplastic resin molded product A or B (armrest, stool, non-slip, etc.) previously formed into a shape corresponding to the shape of the bathtub. In this invention, there is no specific limitation on the shape of the detachable mold part 7 or 8 in the present invention. 3 and 4
Is an example in which a thermoplastic resin molded product A or B is used as a surface layer and a resin tub having a substantially similar shape is manufactured, and the shape of the detachable mold part 7 or 8 used here is thermoplastic. The shape was substantially the same as the removable mold part 2 used for molding the resin molded product A or B. That is, FIG.
4 and FIG. 4, when the detachable mold part 7 is attached to the male mold 3 and the detachable mold part 8 is detached from the female mold 4, a basic flat surface on the surface side and the back side is formed (FIG. 4), when the detachable mold part 7 is detached and the detachable mold part 8 is attached, a shape corresponding to the convex portion of the thermoplastic resin molded product B is formed (FIG. 4). However, the present invention is not limited to this. For example, it is possible to take the opposite configuration, and for example, to manufacture a bathtub having a shape partially different from the shape of the thermoplastic resin molded product A or B, Any shape having a shape different from the shape of A or B may be configured.

There is no particular limitation on the thickness of the thermoplastic resin molded article A or B used for the FRP laminate molding. However, when the thickness is appropriately increased, the occurrence of cracks due to the solvent contained in the polymerizable curable resin material can be prevented, and the deformation of the polymerizable curable resin material due to heat generation during curing can be more favorably prevented. From such a point, the thermoplastic resin molded article A
Alternatively, the thickness of B at the thinnest portion is preferably 0.3 mm or more, and more preferably 0.8 mm or more.

The reinforcing layer 5 may be a cured resin layer made of a polymer curable resin alone, but preferably further contains a fiber reinforcing material as described above. As the fiber reinforcing material, for example, glass fiber or the like can be used. When glass fiber is used, for example, a glass fiber mat formed into a woven or non-woven fabric, or a glass fiber preform formed into a substantially same shape as the thermoplastic resin molded product A or B by spraying or pressing. Can be used. This fiber reinforcement (and the fillers detailed below)
Is used as required mainly to improve the strength of the resin bathtub and to improve the heat resistance. Its content is from 10% by weight to 9% by weight based on the total amount of
It is preferably within the range of 0% by weight.

Injecting into the cell to form the reinforcing layer 5,
As the polymerizable curable resin raw material to be cured, any material having an affinity for the thermoplastic resin molded product A or B, and capable of being polymerized and cured and capable of being tightly integrated with the thermoplastic resin molded product A or B may be used. What is necessary is just to select suitably according to the kind of resin of thermoplastic resin molded articles A or B, etc. For example, unsaturated polyester resin, acrylic resin, vinyl ester resin,
Examples include urethane resins, epoxy resins, and resins modified from these. Among these, as the unsaturated polyester resin, orthophthalic acid type, isophthalic acid type, terephthalic acid type or bisphenol type unsaturated polyester resin, and these acrylic-modified unsaturated polyester resins, and orthophthalic acid type, isophthalic acid type,
A resin composition or the like obtained by adding an acrylic resin to a terephthalic acid-based or bisphenol-based unsaturated polyester resin is used.

When the polymerization-curable resin raw material is polymerized and cured, it is desirable to control the curing conditions so that the thermoplastic resin molded product A or B is not deformed by the heat generated during curing.
Specifically, the heat generation temperature may be prevented from increasing by reducing the amount of the curing agent. Further, it is also effective to degas the polymerizable curable resin material to be filled so that the polymerizable curable resin material does not foam during curing.

Further, a reinforcing filler may be mixed with the polymer-curable resin material and used. As the reinforcing filler, conventionally known various fillers such as aluminum hydroxide, calcium carbonate, glass fiber, carbon fiber, aramid fiber and polyester fiber can be used. These can be used alone or in combination of two or more. Further, these fillers are preferably subjected to a coupling treatment.

Further, in the reinforcing layer 5 at a portion corresponding to the bottom of the bathtub, a reinforcing material such as a veneer plate or a resin plate divided into one or a plurality of pieces, SMC (sheet molding compound), resin concrete and the like can be used. They are,
It is also effective to make a hole on the entire surface so that it can be easily integrated with the polymerizable resin.

The male mold 3 and the female mold 4 include, for example, a mold made of FRP using epoxy resin, vinyl ester resin, unsaturated polyester resin, etc., a mold made of a laminate of FRP and resin concrete, Ni-electrode, and the like. Casting mold (FR
Restrictions on various types of molds that are conventionally known to be usable for FRP lamination molding, such as molds made of metal such as aluminum, which are coated with nickel on the surface of P), and molds reinforced with a rib structure Can be used without. The removable mold part 7 or 8 can be made of the same material as the female mold 4.

The optimum size of the injection port provided in the female mold 4 varies depending on the viscosity of the polymerizable resin for reinforcement. However, the diameter of the injection port is usually 3 mm to 1 mm.
It is set to about 0 mm.

When the detachable mold part 7 or 8 is attached to the male mold 3 or the female mold 4 as shown in FIGS. 3 and 4, for example, when the polymerization curable resin is injected, the position thereof is changed. It is desirable to fix them so that they do not shift.
There is no particular limitation on the fixing method. For example, a double-sided tape may be used, or the male and female molds 3 or 4 may be fixed with screws or the like. When the detachable mold part 7 or 8 is removed to perform the FRP lamination molding, the fixing screw holes provided in the male mold 3 or the female mold 4 may be closed with screws or the like fitted in the holes. . If the detachable mold part 7 or 8 is fixed well, a gap is hardly formed between the male mold 3 and the female mold 4 and the detachable mold part 7 or 8, and the polymerizable curable resin material enters the gap. Demolding can be performed well without performing.

After polymerizing and curing the polymerized curable resin filled in the cell, the female mold 4 and the mold part 8 are preliminarily prepared for the purpose of improving the mold releasability when releasing the integrated FRP reinforced molded article.
It is preferable to apply a release agent to the surface in contact with the polymerizable curable resin material, or to laminate the surface with a material that is difficult to adhere to, such as Teflon.

[0036]

Embodiments of the present invention will be described below.

Example 1 A resin bath was prepared as follows in accordance with the steps shown in FIGS.

A 5-mm-thick acrylic resin plate (trade name: Acrylite PX200, manufactured by Mitsubishi Rayon Co., Ltd.) is vacuum-formed using a female aluminum mold (thermoforming mold 1) to form a bathtub-shaped acrylic resin. The product A was obtained. The plate thickness of the thinnest part of this acrylic resin molded product A was 0.9 mm.

This acrylic resin molded product A in the shape of a bath tub,
The glass fiber preform is placed on the male mold 4 (and the detachable mold part 7 fixed thereto) in this order, and sealed with the peripheral part of the acrylic resin molded product A and the aluminum female mold 3. From 6, the thermosetting resin material was injected. As the thermosetting resin raw material, 100 parts by weight of an unsaturated polyester resin [trade name Yupica 8851, manufactured by Nippon Yupika Co., Ltd.] is added to a curing agent [trade name Permec N, manufactured by NOF Corporation].
Was used. The thickness of the reinforcing layer 5 is 4
mm. Further, in order to release the thermosetting resin material filled in the cell after the polymerization and curing, a wax-like release agent was previously applied to the surface of the female mold 3 in contact with the thermosetting resin.

After confirming that the unsaturated polyester resin was polymerized and cured from the temperature of the unsaturated polyester resin filled in the cell, the female mold 3 was opened to obtain a reinforced acrylic resin bath. Observation of the acrylic resin bath indicated that the resin was filled securely and was a good product without defects such as bubbles.

Example 2 According to the steps shown in FIGS. 2 and 4, a resin bath was prepared as follows.

The same acrylic resin plate as that used in Example 1 was vacuum-formed using a mold in which a detachable armrest-shaped FRP mold part 2 was placed on an aluminum female mold (thermoforming mold 1). Thus, a bathtub-shaped acrylic resin molded product B with armrests was obtained. The plate thickness of the thinnest part of this acrylic resin molded product B was 0.8 mm.

Using this acrylic resin molded product B in the shape of a bathtub with armrests, as shown in FIG. 4, the removable mold part 7 is not attached to the male mold 4 but the detachable mold part 8 is attached to the female mold 3.
The FRP lamination molding was performed in the same manner as in Example 1, except that
A reinforced acrylic resin bathtub with armrests was obtained. Observation of the acrylic resin bathtub with armrests revealed that the resin was reliably filled and was a good product without defects such as air bubbles. In addition, from the results of Example 1 and Example 2, it was confirmed that the same mold can be used well even in bathtubs having different shapes (with or without armrests).

[0044]

As described above, in the present invention, resin bathtubs having almost the same shape except for a part of the shape such as armrests, stools, and non-slip members are formed by the same set of molds (basic type). Mold and a removable mold part). As a result, costs related to the mold used for molding, such as the number of molds required, occupation / replacement time, and storage location, which were problems in the prior art, can be reduced, and resin baths of various designs can be manufactured at lower cost. And can satisfy various demands of consumers.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a manufacturing method of the present invention.

FIG. 2 is a schematic sectional view showing one embodiment of the manufacturing method of the present invention.

FIG. 3 is a schematic sectional view showing one embodiment of the manufacturing method of the present invention.

FIG. 4 is a schematic sectional view showing one embodiment of the manufacturing method of the present invention.

[Explanation of symbols]

 A, B Thermoplastic resin molded article 1 Thermoforming mold 2 Removable mold part 3 Female mold 4 Male mold 5 Reinforcement layer 6 Inlet 7, 8 Removable mold part

Claims (3)

[Claims] 1. A method for manufacturing a resin bathtub which includes a molding step using a mold having a shape corresponding to the shape of a bathtub to be manufactured, wherein the mold has a part to which a mold part can be attached and detached. A method for manufacturing a resin bathtub, wherein the molding step is performed by attaching or detaching the mold part according to the shape of the bathtub to be intended. 2. The method for producing a resin bathtub according to claim 1, wherein said forming step is a step of vacuum forming or pressure forming a thermoplastic resin plate. 3. The molding step is a step of placing at least a thermoplastic resin molded article and a fiber reinforcing material in a mold, injecting a polymer curable resin material into the mold, and polymerizing and curing. A method for producing the resin bathtub according to the above.