JP2578042B2 - Manufacturing method of synthetic resin molded products - Google Patents

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 synthetic resin molded article such as a bathtub made of fiber reinforced plastic (hereinafter referred to as "FRP") by a hand lay-up method.

[0002]

2. Description of the Related Art As means for producing synthetic resin molded articles,
A manufacturing method using a hand lay-up method is known. The hand lay-up method is often used when manufacturing a bathtub made of FRP, and the steps will be described as follows.

[0003] First, after a mold release agent is applied to the surface of a cleaned mold, a gel coat resin is sprayed and cured by heating or the like to form a gel coat layer.
Next, a glass fiber sheet and a synthetic resin are laminated on the gel coat layer, and defoaming and curing are performed. After a while
A reinforcing material, a bottom plate, a footboard, etc. are attached, and a glass fiber sheet and a synthetic resin are further laminated. Then, after defoaming and curing, and then demolding, an intended FRP bath is obtained.

[0004]

As shown in FIG. 5, the bathtub 10 manufactured as described above (however, legs and the like are not shown) has a smooth surface 10a in contact with the molding die 20. Back 1 which is not exposed during use
Since 0b is formed by laminating a glass fiber sheet with a synthetic resin and molding, it has an uneven surface.

By the way, the portion 11 of the bathtub 10 where the drain port is provided is formed so as to project in advance to the back surface 10b side, in other words, to be depressed when viewed from the front surface 10a side.
After demolding, the site 11 is pierced to form a drain port. When the bathtub 10 is installed, a drain pipe is connected to the drain port thus formed from the back surface 10b side. However, as described above, since the back surface 10b of the bathtub around the drain port is an uneven surface, water leakage occurs between the bathtub 10 and the drain pipe. Moreover, just by installing packing between them,
It is difficult to prevent water leakage. Therefore, conventionally, a process of polishing and smoothing the back surface around the drain port with a grinder has been performed, which requires time and effort.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method for solving the above-mentioned conventional drawbacks, which is characterized in that a synthetic resin material is applied to the surface of a mold by a hand lay-up method. In the method of producing a molded article by coating, after forming a synthetic resin layer on a molding die, before curing, a pressing die having a smooth surface is attached to a required portion of the synthetic resin layer, and To form a flat surface on the back surface.

[0007]

According to the method of the present invention, for example, the bathtub is
When manufacturing with RP, after determining the overall shape, to the part where smoothness is required such as drain pipe connection on the back side,
Before the curing, the pressing mold is attached and then cured. Therefore, if the pressing mold is removed after the hardening of the synthetic resin material, a flat surface is formed at the corresponding portion. Therefore, it is not necessary to grind the surroundings of the drain port with a grinder as in the related art, and the prevention of water leakage is also ensured.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings showing embodiments. FIG. 1 shows a state during the process of manufacturing the bathtub A by FRP. Even when the method of the present invention is applied, the procedure is the same as that of the conventional method up to the final curing step. That is, a release agent is applied to the surface of the mold 1 that has been cleaned, and a gel coat resin is sprayed to form a gel coat layer 2, and then a glass fiber sheet and a synthetic resin are laminated on the gel coat layer 2, After defoaming and hardening, a reinforcing material, a bottom plate, a footboard (all not shown), etc. are attached, and a glass fiber sheet and a synthetic resin are laminated to form a synthetic resin layer 3 having a constant thickness. Up to the point where defoaming is performed, it is the same as the conventional one.

The present invention is characterized in that after the overall shape of the bathtub A is determined as described above, before the synthetic resin material is hardened, the pressing die 5 is pressed against the drainage forming portion 4 and mounted. Having. As shown in FIG. 2, the stamping die 5 used here is manufactured in a disk shape having a concave portion 5a at the center and an annular smooth surface 5b around the concave portion 5a.
In a, a ventilation hole 5c is formed. The material of the press mold 5 is not particularly limited, such as synthetic resin, ceramic, metal, etc., but it is necessary that the press mold 5 can be easily removed from the molded product.

When the pressing die 5 is pressed against the drainage forming portion 4 in the bathtub A, the flat surface 5b of the pressing die 5 forms a flat surface around the draining hole, that is, a region corresponding to a connection portion of the drainage pipe. Formed. At this time, the synthetic resin material at the drain port rises into the concave portion 5a at the center of the die 5 and the air in the concave portion 5a is discharged to the outside through the ventilation hole 5c. Can be closely contacted.

If the pressing die 5 is made of a transparent material, it is checked whether or not a flat surface is surely formed at a predetermined portion when the pressing die 5 is attached to the synthetic resin layer 3.
It can be checked whether or not air bubbles remain between the smooth surface 5b of the pressing die 5 and the synthetic resin layer 3. This is useful when producing a product having a thin synthetic resin layer 3.

In this manner, a final curing step such as heating is performed with the pressing die 5 attached to the back surface of the bathtub A. Finally, the mold 5 is removed from the cured synthetic resin layer 3 and the molded product is removed from the mold 1 to obtain the desired bathtub A. In the bathtub A, since the connection portion of the drainage pipe is formed on a flat surface, it is not necessary to perform a grinder process, and if the drainage pipe is connected via packing, it is possible to reliably prevent water leakage between the two. It is.

In some cases, it is necessary to provide a flat surface on the back surface of the bathtub other than around the drain port.
For example, as shown in FIG. 3, in a floor pan P in which a bathtub A, an apron section B, and a washing section C are integrally formed, an overflow pipe 6 is attached to the back surface of the bathtub A. In this case, the part to which the overflow pipe 6 is to be attached must be formed on a flat surface. However, as shown in the figure, since the apron portion B is formed integrally with the outside of the bathtub A, it is difficult to mount the press die 5. Therefore, in this embodiment,
As shown in FIG. 4, the holder 7 whose bolt 7b can be adjusted in length by rotating the nut 7a is inserted between the bathtub A and the apron B, and the pressing mold 5 is inserted at one end into the bathtub. It was decided to press and hold a required part in A.
In this state, after performing the hardening treatment, if the holder 7 and the pressing die 5 are removed, a flat surface can be provided in the mounting portion of the overflow tube 6 in the bathtub A.

In addition, when it is necessary to form a flat surface on the back surface of the bathtub, when connecting a piping for circulating hot water to the bathtub when installing the bathtub in the bathroom, air is mixed in the bathtub. A case where various pipes are connected to the outer surface of a so-called bubble bath in which hot water is circulated can be cited.
The present invention can be applied to the production of various synthetic resin molded articles such as waterproof pans and water tanks, in addition to the production of bathtubs by FRP. Furthermore, specific embodiments of the present invention do not prevent appropriate modifications according to the implementation situation.

[0015]

According to the method of manufacturing a synthetic resin molded product according to the present invention, before the synthetic resin layer is cured, a pressing die is attached to a necessary portion of the molded product to form a flat surface in advance, and then the Is hardened to obtain a molded product, so that there is no need to perform a polishing treatment by a conventional grinder process. Therefore,
The number of work steps is reduced, and the production efficiency is improved. Moreover,
Since a flat surface can be reliably formed at a necessary portion, for example, when a drain pipe or the like is connected, it is possible to reliably prevent water leakage at the connection portion.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of an embodiment when the present invention is applied to a method for manufacturing a bathtub.

FIG. 2 shows a stamp used in the present invention,
(A) is a perspective view seen from the back side, and (B) is a front sectional view.

FIG. 3 shows a floor pan in which a bathtub, an apron part and a washing place part are integrally formed, wherein (A) is a perspective view and (B).
Is a longitudinal sectional view of the main part, showing a state in which an overflow pipe is attached to a bathtub.

FIG. 4 is a view showing an embodiment of another aspect of the present invention, in which a flat surface is formed at a mounting portion of the overflow pipe on the back surface of the bathtub when the bathtub and the apron portion are integrally formed. It is a longitudinal cross-sectional view.

FIG. 5 shows a conventional manufacturing process of a bathtub,
(A) is a perspective view showing a state in which a synthetic resin layer is formed on a mold, and (B) is a longitudinal sectional view thereof.

[Explanation of symbols]

A: Bathtub 1 ... Mold 2 ... Gel coat layer 3 ... Synthetic resin layer 4 ... Drainage port formation site 5 ... Push mold 6 ... Overflow pipe

Claims (1)

(57) [Claims] 1. A method of manufacturing a molded article by applying a synthetic resin material to a surface of a mold by a hand lay-up method, wherein a synthetic resin layer is formed on the mold, and before the synthetic resin layer is cured, the synthetic resin layer is formed. A method for producing a synthetic resin molded product, comprising: attaching a pressing die having a smooth surface to a required portion of a layer to form a flat surface on a back surface of the molded product.