JP2006315374A - Manufacturing method of bathtub - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a lightweight bathtub stabilized in its quality, having good post-processability and excellent in impact resistance. <P>SOLUTION: A male mold is covered with a thermoplastic resin molded product while a female mold is arranged on the side opposite to the male mold so as to leave a predetermined interval from the thermoplastic resin molded product to form a cell and, in a state that the peripheral part of the thermoplastic resin molded product and the peripheral part of the male mold are sealed to clamp the male and female molds, a resin mixed liquid, which contains a polymerizable resin raw material, at least one kind of an inorganic filler selected from the group consisting of glass balloons, aluminum hydroxide and silica and a phosphoric ester containing a (meth)acryloyloxy group represented by the formula (1) (wherein R<SP>1</SP>is H or CH<SB>3</SB>and n is 1 or 2), is injected in the cell and cured to form a reinforcing material layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a lightweight bathtub with excellent impact resistance.

  A methacrylic resin bathtub is usually a methacrylic resin molded product produced by heating and softening a methacrylic resin sheet and forming it into a desired bathtub shape by vacuum forming. The material is produced by spraying a material with a spray gun or laminating by a hand lay-up method, and smoothing this layer while defoaming, followed by curing to form a reinforcing material layer.

  However, in the manufacturing method of the bathtub, since the FRP material is sprayed, hand laid up, and further smoothed by an operator, the working environment and production efficiency are poor, and excess FRP material generated during production Disposal is also an environmental problem. In addition, the use of glass fibers is essential, and there are problems in terms of cost increase and post-processability. On the other hand, as a method for improving production efficiency and working environment, for example, an attempt to fill a resin containing a filler between a vacuum-formed thermoplastic resin molded product and a mold, polymerize, cure, and integrate is disclosed. (For example, refer to Patent Document 1).

  However, if a material that does not contain glass fiber is used as the backing reinforcing material, the structure of the reinforcing material layer becomes a resin (filler-containing), which may cause problems such as deterioration in dimensional accuracy and reduction in strength. In particular, from the viewpoint of strength, it is necessary to increase the thickness of the reinforcing material layer, which may cause a problem that the weight increases.

  For artificial marble obtained by polymerizing and curing a composition containing a resin and a specific inorganic filler, a method for producing artificial marble that is excellent in mechanical properties and inexpensive as an attempt to improve strength is disclosed (for example, , See Patent Document 2). Since the invention disclosed in Patent Document 2 is intended for artificial marble with improved mechanical strength, the effect and weight reduction when used as a reinforcing material layer for articles having a complicated shape such as a bathtub The effect on is not shown.

JP-A-5-237854 JP 2004-26556 A

  The present invention has been made in view of the above-described state of the art, and an object of the present invention is to provide a method for manufacturing a lightweight bathtub having good impact resistance and light weight.

  The present invention, which has solved the above-mentioned problems, covers a thermoplastic resin molded product molded in a predetermined shape in advance on a male mold having substantially the same shape as the thermoplastic resin molded product, and has a predetermined distance from the thermoplastic resin molded product. A cell is formed by disposing a female mold on the opposite side of the male mold, and the peripheral portion of the thermoplastic resin molded product and the peripheral portion of the female mold are sealed and clamped, The polymerizable resin raw material, at least one inorganic filler selected from the group consisting of glass balloon, aluminum hydroxide, and silica, and the following formula (1) are introduced into the cell from the female inlet. ) A bathtub manufacturing method in which a resin mixture containing a phosphate ester containing an acryloyloxy group is injected and cured to form a reinforcing material layer.

(In the formula, R ¹ represents H or CH ₃ , and n represents 1 or 2.)

  According to the present invention, it is possible to manufacture a bathtub having a good impact resistance and a light weight.

  In the method for manufacturing a bathtub according to the present invention, a thermoplastic resin molded product molded in a predetermined shape is placed on a male mold having substantially the same shape as the thermoplastic resin molded product, and the thermoplastic resin molded product and a predetermined interval are covered. A cell is formed by disposing a female mold on the opposite side of the male mold, and the peripheral portion of the thermoplastic resin molded product and the peripheral portion of the female mold are sealed and clamped, The polymerizable resin raw material, at least one inorganic filler selected from the group consisting of glass balloon, aluminum hydroxide, and silica, and the above formula (1) are introduced into the cell from the female inlet. ) A method of manufacturing a bathtub in which a resin mixture containing a phosphoric ester containing an acryloyloxy group is injected and cured to form a reinforcing material layer.

The thermoplastic resin molded product used in the present invention is usually produced by thermoforming a thermoplastic resin plate.
As a thermoplastic resin board used for manufacture of a thermoplastic resin molded article, a methacryl resin board, a polystyrene board, an ABS resin board, or these laminated boards can be mentioned, for example. Examples of the thermoforming method used for the production of the thermoplastic resin molded product include methods such as vacuum forming, pressure forming, and press forming. In vacuum forming or pressure forming, auxiliary forming using a plug or the like can also be performed.

  The thickness of the thermoplastic resin molded product is not particularly limited, but if it becomes too thin, cracks may occur in the diluent contained in the resin mixture, or it may be deformed by heat generated when the resin mixture is cured, Deformation may occur due to the injection pressure of the resin mixture. From this point, the thickness of the thermoplastic resin molded product is 0.3 mm or more, preferably 0.8 mm or more at the thinnest place. Further, if necessary, a thermoplastic resin molded product manufactured from a thermoplastic resin plate that has been printed, laminated with a film, or further patterned with a gel coat resin may be used, or a thermoplastic resin may be used. The molded product may be printed, laminated with a film, or patterned with a gel coat resin.

  In particular, the methacrylic resin sheet disclosed in Japanese Patent Publication No. 6-70098 is excellent in thermoforming processability and solvent resistance, and can be preferably used as the thermoplastic resin plate in the present invention. That is, an acrylic resin sheet obtained by polymerizing methyl methacrylate alone or a monomer mixture of 60% by mass or more of methyl methacrylate and 40% by mass or less of acrylic acid ester in the presence of a polymerization initiator. A polymerization initiator of 0.001 to 0.50% by mass and a chain transfer agent of 0.01 to 2.0% by mass are added to the total amount of the monomer, and 5 to 50% of polymerization is performed at a temperature of 70 to 120 ° C. Syrup, and then 0.02-1.0% by weight crosslinker and 0.01-0.50% by weight polymerization initiator are added to the resulting syrup in the mold First, the polymerization degree of a trunk polymer crosslinked by a crosslinking agent by cast polymerization in which heat treatment is performed in warm water at 40 to 90 ° C. for 0.2 to 10 hours and then at 90 to 150 ° C. for 0.05 to 4 hours. Is an intrinsic viscosity [η] of 0.05 to It is preferred to use 0.15 as the acrylic resin sheet range (l / g) as the thermoplastic resin plate.

The predetermined shape in this invention means the shape of the bathtub to manufacture.
The male mold having substantially the same shape as the thermoplastic resin molded product used in the present invention and the female mold disposed on the opposite side of the male mold at a predetermined interval from the thermoplastic resin molded product include epoxy resins and vinyl ester resins. , FRP molds using unsaturated polyester resin, etc., molds made of laminates such as FRP and resin concrete, Ni electric molds (FRP mold surfaces coated with nickel), aluminum alloys, etc. And those reinforced with a rib structure.

  After the resin mixture injected into the cell is polymerized and cured to form a reinforcing material layer, the manufactured bathtub is released from the female mold, so a release agent is applied to the inner surface of the female cell where the resin mixture comes into contact. Alternatively, it is preferable to laminate a material such as Teflon (registered trademark). Since the male mold is required to have a function as a presser, it is necessary to make it substantially the same shape as the thermoplastic resin molded product. By setting it as such a shape, a deformation | transformation of a thermoplastic resin molded product can be prevented and a shape can be hold | maintained.

  The interval between the cells formed by the thermoplastic resin molded product and the female mold may be set so that the thickness of the reinforcing material layer set when the resin mixture is completely filled in the cell. It is not necessary that the cell spacing of this cell matches the thickness of the reinforcing material layer of the completed bathtub. Specifically, for example, in order to reduce the flow resistance of the resin mixed liquid at the time of injection, the cell interval at the time of injection is set to the thickness of the reinforcing material layer of the completed bathtub +1 to 10 mm, and from immediately after injection to the completion of filling. In the meantime, the cell interval may be adjusted so that a reinforcing material layer having a predetermined thickness is obtained. In addition, the cell interval from immediately after injection to completion of filling is controlled so that the mold clamping pressure of the male and female molds is gradually increased and no pressure exceeding a predetermined pressure is applied, and the pressure of the resin mixture in the cell is controlled. It is desirable to suppress the extreme rise.

  The thickness of the reinforcing material layer thus formed is preferably preferably 2 to 20 mm, more preferably 5 to 15 mm. The bottom of the bathtub is preferably 10 mm or more in order to have sufficient impact strength.

  The resin mixed solution is injected into the cell from the female injection port. The thermoplastic resin molded product and the female mold are sealed by packing or the like at their peripheral portions, and the mold is clamped to prevent the resin mixture from leaking out of the cell.

  Examples of the polymerizable resin material contained in the resin mixture include unsaturated polyester resins, melamine resins, vinyl ester resins, acrylic resins, and epoxy resins. Of these, unsaturated polyester resins are preferred, and iso-unsaturated polyester resins are particularly preferred because they are difficult to hydrolyze in acids and alkalis, are inexpensive and have good storage stability. In the present invention, it is preferable to use a polymerizable resin raw material containing the resin and a monomer that can be polymerized and cured together with the resin as a diluent. In the present invention, such a diluent is used. And a mixture of the above resins are also included in the polymerizable resin raw material.

  The monomer that can be used as a diluent is preferably a liquid monomer such as styrene, vinyl toluene, divinylbenzene, α-methylstyrene, chlorostyrene, dichlorostyrene, and among them, styrene is more preferable. The polymerizable resin raw material containing the diluent preferably contains the diluent in an amount of 40 to 50 mass%, more preferably 43 to 48 mass%, based on the total mass of the resin and the diluent. When the content of the diluent is 40% by mass or more, a resin mixed solution having an appropriate viscosity can be easily obtained, and the resin mixed solution can be quickly injected into the cell. Also, a desired amount of inorganic filler can be easily mixed. On the other hand, when the content of the diluent is 50% by mass or less, when the resin mixed solution is cured in the cell, the shrinkage becomes small and an excellent reinforcing material layer free from defects such as cracks can be easily formed.

  As the inorganic filler contained in the resin mixed solution, aluminum hydroxide, silica and glass balloon can be used, and these may be used alone or in combination of two or more. Of these, glass balloons are preferred. The glass balloon is a white glass micro hollow sphere powder, and its composition is soda-lime borosilicate glass, so it has excellent weather resistance and heat resistance, and since it is a hollow particle, heat insulation and light weight. Excellent effects can be achieved.

The glass balloon preferably has a true density in the range of 0.3 to 0.7 g / cm ³ . When a glass balloon having a true density of 0.3 g / cm ³ or more is used, it is possible to form a reinforcing material layer that is difficult to separate when mixed with a resin mixture and has excellent mechanical properties. Further, when a glass balloon having a true density of 0.7 g / cm ³ or less is used, the weight of the formed reinforcing material layer can be reduced.

  Moreover, since the viscosity of the resin mixed solution can be in a suitable range, the inorganic filler is preferably used in a range of 10 to 50 parts by mass with respect to 100 parts by mass of the polymerizable resin raw material. More preferably, it is used in the range of 25 to 35 parts by mass. When the amount of the inorganic filler used is 10 parts by mass or more, the impact strength of the obtained bathtub is improved, and when the amount of the inorganic filler used is 50 parts by mass or less, the resin mixture can be injected quickly. Therefore, it can prevent becoming unfilled by the viscosity rise by hardening reaction.

  Examples of the phosphoric acid ester containing a (meth) acryloyloxy group represented by the following formula (1) contained in the resin mixture include (2-hydroxyethyl) acrylate acid phosphate and (2-hydroxyethyl) methacrylate acid phosphate. Can be mentioned. Each of these may be a mixture of those in which the value of n in the following formula (1) is 1 and 2. Further, (2-hydroxyethyl) acrylate acid phosphate and (2-hydroxyethyl) methacrylate acid phosphate may be used in combination. Among these, (2-hydroxyethyl) methacrylate acid phosphate (which may be a mixture of n having a value of 1 and 2 in the following formula (1)) is preferable.

(In the formula, R ¹ represents H or CH ₃ , and n represents 1 or 2.)

  It is preferable that the addition amount of the phosphate ester containing the (meth) acryloyloxy group is 0.01 to 5 parts by mass with respect to 100 parts by mass of the inorganic filler. In particular, when a glass balloon is used as the inorganic filler, it is preferably 0.01 to 3 parts by mass, more preferably 0.1 to 1 part by mass with respect to 100 parts by mass of the glass balloon. Addition of 0.01 part by mass or more of a phosphate ester containing a (meth) acryloyloxy group to 100 parts by mass of the inorganic filler can greatly improve mechanical properties. Moreover, when the phosphate ester containing a (meth) acryloyloxy group is 5 mass parts or less, cost can be reduced.

  In the present invention, it is preferable to inject a resin mixed solution having a liquid temperature of 20 ° C. to 60 ° C., preferably 30 ° C. to 45 ° C., into the cell. When the liquid temperature of the resin mixture is 20 ° C. or higher, the fluidity is improved and air in the cell is easily removed, the appearance is improved without defects such as resin removal in the cured bath, and curing in the mold is achieved. This is sufficiently performed and warpage can be prevented. Moreover, when the liquid temperature is 60 ° C. or lower, volatilization of volatile components contained in the resin mixed liquid can be suppressed. Thereby, the deterioration of the working environment can be suppressed. As a method for adjusting the liquid temperature of the resin mixed solution within the above range, a method of adjusting the temperature by charging the resin mixed solution into a storage tank with a jacket and circulating hot water in the jacket can be used.

  The resin mixed solution usually has a viscosity in the range of 100 mPa · s to 3000 mPa · s. When the viscosity of the resin mixed solution is 100 mPa · s or more, the sedimentation of the inorganic filler is slowed down, and the blockage due to the sedimentation of the inorganic filler in pipes and storage tanks, the composition change of the resin mixed solution, etc. are stirred. This can be easily prevented. Further, when the viscosity of the resin mixed solution is 3000 mPa · s or less, the injection time of the resin mixed solution can be shortened and rapidly injected into the cell. Thereby, injection into the cell becomes insufficient due to an increase in viscosity due to the reaction and the like, and it is possible to prevent air accumulation and generation of an unfilled portion.

  Examples of the method for adjusting the viscosity of the resin mixed solution include a method for adjusting the content of the diluent, a method for adjusting the amount of the inorganic filler used, and the like.

  It is preferable that the resin mixed solution contains a curing agent. In order to advance the curing in the cell efficiently, it is preferable to use a combination of two or more curing agents having a 10-hour half-life temperature of 3 ° C. or more. In particular, it is preferable to use a combination of two or more ketone peroxide (room temperature curing) curing agents such as methyl ethyl ketone peroxide and acetylacetone peroxide. It is preferable that the usage-amount of a hardening | curing agent is 0.3-5 mass parts normally with respect to 100 mass parts of polymeric resin raw materials. When the amount of the curing agent used is 0.3 parts by mass or more, the curing reaction can be started without delay. Moreover, when the usage-amount of a hardening | curing agent shall be 5 mass parts or less, hardening time can be shortened, production efficiency can be improved, and cost can be reduced.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, in the present Example, evaluation of the bathtub was performed by the method of following 1) -3).

1) Appearance of bathtub The appearance of the obtained bathtub was visually inspected and evaluated according to the following criteria.
○ Appearance was good; there were no defects such as cracks and air accumulation (unfilled) × Appearance defect; defects such as cracks and air accumulation (unfilled) were observed

2) Drop weight impact strength A test piece of 10 cm × 10 cm × original thickness (mm) was cut out from the bottom of the bathtub to prepare a test sample. A 50% fracture energy was determined according to JIS K7211, except that a 200 g steel ball was used as the weight. The steel ball was applied to the thermoplastic resin side (methacrylic resin side).

3) Specific gravity After a 3 cm × 3 cm × original thickness (mm) test piece was cut out from the bottom of the bathtub and the acrylic resin layer (thermoplastic resin) on the surface was removed, a specific gravity measuring device manufactured by Shimadzu Corporation, SGM- The specific gravity of the reinforcing material layer was measured using 300P (trade name) (measurement principle according to JIS Z8807. Water temperature at measurement: 23 ° C.).

[Example 1]
In this example, a bathtub was manufactured using a thermoplastic resin molded product manufactured by thermoforming a methacrylic resin plate as follows.
First, a thermoplastic resin molded product 1 having a shape shown in FIG. 1 is formed by thermoforming using a vacuum forming machine using a methacrylic resin plate (Acrylite (registered trademark) PX200, manufactured by Mitsubishi Rayon Co., Ltd.) having a thickness of 5 mm. Prepared. This shape includes a stool portion 10 and an armrest portion 11 as shown in FIG. A bathtub having a complicated shape was manufactured.

  Next, as shown in FIG. 2 (A), a mold having substantially the same shape as the inner surface shape of the thermoplastic resin molded product 1 was used as the male mold 2. The male mold 2 is an FRP mold using an epoxy resin as a matrix resin. As shown in FIGS. 2A and 2B, a male mold 2 is covered with a thermoplastic resin molded product 1, and an aluminum alloy female mold 3 is placed on the bottom surface (upward in the figure) of the thermoplastic resin molded product 1. On the other hand, it was covered with an interval of 10.7 mm (expected to have a polymerization shrinkage of 0.7%). The male mold 2 and the female mold 3 were both tempered by embedding a hot water circulation pipe inside the mold.

  Next, the periphery of the thermoplastic resin molded product 1 and the female mold 3 is sealed with an elastic seal packing 4, and is pressurized from above and below using an appropriate mold clamping machine and sealed to form a cell 6. . The injection port 5 provided in the female mold 3 has a diameter of 8 mm, and the cells arranged as shown in FIG. 2B are arranged from the injection port 5 while narrowing the distance between the male mold 2 and the female mold 3 with a mold clamping machine. Resin mixed solution 7 was injected. The mold temperature at that time was set to a male mold of 90 ° C. and a female mold of 60 ° C.

The resin mixed solution 7 was adjusted as follows. To 100 parts by mass of a polymerizable resin raw material prepared by mixing 55 parts by mass of an iso-type unsaturated polyester resin (trade name: Iupika 4542P, manufactured by Nippon Iupika Co., Ltd.) and 45 parts by mass of styrene, a glass balloon (product name: glass Bubbles S60, true density 0.6 g / cm ³ , manufactured by Sumitomo 3M Co., Ltd.) 30 parts by mass, phosphate ester containing (meth) acryloyloxy group represented by the following formula (2) (trade name: JPA- 514: 0.17 parts by mass of a mixture of n = 1 and n = 2 (molar ratio 1: 1) manufactured by Johoku Chemical Industry Co., Ltd. was obtained to obtain a resin mixed solution.

  The resin mixture was then transferred to a jacketed storage tank and kept warm at 32 ° C. by circulating hot water. The resin mixed solution had a viscosity (32 ° C.) of 280 mPa · s.

  As a curing agent, Permec NR (trade name: methyl ethyl ketone peroxide purity 55%, 10 hour half-life temperature 111 ° C., manufactured by NOF Corporation) and Percure AH (trade name: acetylacetone peroxide purity 34%, 10 hour half) A curing agent mixture was prepared by mixing two curing agents of an initial temperature of about 106 ° C., manufactured by NOF Corporation at a mass ratio of 1: 1.

  Immediately before injection, the resin mixture and the curing agent mixture are supplied in a ratio of 2 parts by mass of the curing agent mixture to 100 parts by mass of the polymerizable resin raw material contained in the resin mixture, and mixed with a static mixer. Injected into the cell 6. With the injection of the resin mixture containing the curing agent mixture, the air present in the cell 6 was exhausted from the exhaust port 8. In this way, the resin mixture filled in the cell was polymerized and cured to form a reinforcing material layer. Thereafter, the mold was removed to obtain a bathtub.

  Despite the complicated shape, the cell was filled without leaving an unfilled area in the cell and there was no air accumulation, and the appearance of this bathtub was good. Moreover, since it is not a reinforcing material layer using glass fiber, it is easy to perform post-processing such as surface mounting of the leg attachment portion in the lower part of the bathtub and polishing of the repaired portion, and the working environment during the post-processing can be improved. Table 1 shows the raw material formulation and the evaluation results.

[Example 2]
In order to adjust the thickness of the bottom surface of the bathtub to 14 mm, the bathtub was manufactured in the same manner as in Example 1 except that the interval between the female mold 3 and the thermoplastic resin molded article 1 was set to 15 mm (expected to have a polymerization shrinkage of 0.7%). And evaluated. Despite the complex shape, the cell was filled without leaving an unfilled region, and the appearance was good. Moreover, since it is not a reinforcement layer using glass fiber, post-processing was easy and the working environment at the time of processing could be improved. Table 1 shows the raw material formulation and the evaluation results.

[Example 3]
A bathtub was produced and evaluated in the same manner as in Example 1 except that the amount of the phosphate ester containing a (meth) acryloyloxy group was 10 parts by mass. Despite the complicated shape, the bath was filled without leaving an unfilled area in the cell, and the appearance of this bathtub was good. Moreover, since it is not a reinforcing material layer using glass fiber, post-processing is easy and the working environment during processing can be improved. Table 1 shows the raw material formulation and the evaluation results.

[Example 4]
A bathtub was produced and evaluated in the same manner as in Example 1 except that 150 parts by mass of aluminum hydroxide (trade name: BW-33, manufactured by Nippon Light Metal Co., Ltd.) was used as the inorganic filler. The appearance and impact characteristics of this bathtub were good. The evaluation results are shown in Table 2.

[Example 5]
A bathtub was produced and evaluated in the same manner as in Example 1 except that 10 parts by mass of silica (trade name: G-300, manufactured by Tosoh Corporation) was used as the inorganic filler. The appearance and impact characteristics of this bathtub were good. The evaluation results are shown in Table 2.

[Comparative Example 1]
A bathtub was manufactured and evaluated in the same manner as in Example 1 except that a phosphate ester containing a (meth) acryloyloxy group was not used. Despite the complicated shape, the bath was filled without leaving an unfilled area in the cell, and the appearance of this bathtub was good. Moreover, since it is not a reinforcing material layer using glass fiber, post-processing is easy and the working environment during processing can be improved. Table 1 shows the raw material formulation and the evaluation results. As shown in Table 1, the impact performance was inferior to that of the bathtub of Example 1.

[Comparative Example 2]
The inorganic filler is changed to 30 parts by mass of glass balloon (trade name: Glass Bubbles S60, true density 0.6 g / cm ³ , manufactured by Sumitomo 3M Ltd.) to 150 parts by mass of calcium carbonate, and the liquid temperature of the resin mixture A bath was manufactured and evaluated in the same manner as in Comparative Example 1 except that the temperature was 35 ° C. The viscosity (35 ° C.) of the resin mixed solution was 1000 mPa · s.
Despite the complicated shape, the cell was filled without leaving an unfilled area in the cell and there was no air accumulation, and the appearance of this bathtub was good. In addition, since it is not a reinforcing material layer using glass fiber, post-processing such as surface mounting of the leg attachment portion at the lower part of the bathtub and polishing of the repaired portion is easy, and the working environment at the time of processing can be improved. However, as shown in Table 1, the impact strength was low compared to the bathtub of the example.
Table 1 shows the raw material formulation and the evaluation results. Further, the specific gravity of the reinforcing material layer is large and the weight cannot be reduced.

[Comparative Example 3]
In order to adjust the temperature of the resin mixture to 40 ° C. and adjust the thickness of the bottom of the bathtub to 14 mm, the bathtub was prepared in the same manner as in Comparative Example 2 except that the gap between the female mold 3 and the thermoplastic resin molded article 1 was set to 15 mm. Manufactured and evaluated. The viscosity (40 ° C.) of the resin mixture was 900 mPa · s.
Despite the complicated shape, the cell was filled without leaving an unfilled area in the cell and there was no air accumulation, and the appearance of this bathtub was good. In addition, since it is not a reinforcing material layer using glass fiber, post-processing such as surface mounting of the leg attachment portion at the lower part of the bathtub and polishing of the repaired portion is easy, and the working environment at the time of processing can be improved. Table 1 shows the raw material formulation and the evaluation results. The result of the drop weight impact strength test was good, but the specific gravity of the reinforcing material layer was so great that the weight could not be reduced.

[Comparative Example 4]
A bathtub was manufactured and evaluated in the same manner as in Example 4 except that a phosphate ester containing a (meth) acryloyloxy group was not used. The appearance of this bathtub was good, but the impact properties were inferior. The evaluation results are shown in Table 2.

[Comparative Example 5]
A bathtub was manufactured and evaluated in the same manner as in Example 5 except that a phosphate ester containing a (meth) acryloyloxy group was not used. The appearance of this bathtub was good, but the impact properties were inferior. The evaluation results are shown in Table 2.

  The method for manufacturing a bathtub of the present invention is suitable for manufacturing a bathtub having good post-processability, stable quality, excellent impact resistance, and light weight.

It is the schematic which shows an example of a thermoplastic resin molded product. It is sectional drawing for demonstrating an example of embodiment of the manufacturing method of the bathtub of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermoplastic resin molded product 2 Male type 3 Female type 4 Seal packing 5 Inlet 6 Cell 7 Resin liquid mixture 8 Air vent 10 Stool part 11 Armrest part

Claims (1)

A thermoplastic resin molded product molded in advance in a predetermined shape is placed on a male mold having substantially the same shape as the thermoplastic resin molded product, and a female is placed on the opposite side of the male mold at a predetermined interval from the thermoplastic resin molded product. A cell is formed by disposing a mold, and the periphery of the thermoplastic resin molded product and the periphery of the female mold are sealed and clamped, and then the inside of the cell is inserted from the inlet of the female mold. And a phosphate ester containing a polymerizable resin raw material, at least one inorganic filler selected from the group consisting of glass balloon, aluminum hydroxide and silica, and a (meth) acryloyloxy group represented by the following formula (1): The manufacturing method of the bathtub which inject | pours the resin liquid mixture containing this and hardens this and forms a reinforcing material layer.

(In the formula, R ¹ represents H or CH ₃ , and n represents 1 or 2.)

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