Bathtub and manufacturing method thereof

Abstract

To provide a bathtub in which a heat insulation layer is formed by reaction injection molding of a thermosetting resin composition on the external surface of a bathtub body.SOLUTION: The manufacturing method of a bathtub which has a bathtub body and a heat insulation layer formed on the external surface of the bathtub body includes: a process of arranging the bathtub body on a lower die having a recess that is formed along the shape of the external surface of the bathtub; a process of arranging an upper die having a protrusion that is formed along the shape of the internal surface of the bathtub body; a process of injecting a thermosetting resin composition in a cavity existing between the lower die and the bathtub body; and a process of forming the heat insulation layer that is composed of a hardening matter of the thermosetting resin composition, on the external surface of the bathtub body, by hardening the thermosetting resin composition.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bathtub and a method for manufacturing the same. [Background technology]

[0002] When the hot water in a bathroom bathtub cools down, it has to be reheated, so from the perspective of energy conservation, it is necessary to make it as difficult as possible for the hot water to cool down. Possible methods for doing this include keeping the entire bathroom warm, or placing a heat-retaining lid over the bathtub. However, it is difficult to achieve overall energy conservation by keeping the entire bathroom warm. Also, placing a heat-retaining lid over the bathtub relies on the awareness of the user, so its effectiveness is limited. Therefore, instead of or in addition to these methods, methods of installing heat-retaining material around the bathtub itself are being considered.

[0003] Patent Document 1 describes a method for forming insulation on the back of a bathtub body by placing the bathtub body upside down on a turntable and spraying a liquid foaming agent that forms insulation such as polyurethane foam onto the back of the bathtub body, characterized in that the air in the inner space of the bathtub body placed upside down on the table is evacuated through a suction port provided on the table, and the above spraying operation is performed while the bathtub body is adsorbed to the table.

[0004] Patent Document 2 describes a method for forming insulation on the back of a bathtub body by placing the bathtub body, which has a flange integrally formed on the upper peripheral edge, upside down on a table and spraying a liquid foaming concentrate that forms insulation such as polyurethane foam onto the back of the bathtub body, characterized in that a pallet with a flat mounting surface is used as a work table for spraying, and the above-mentioned spraying work is carried out while the flange portion of the bathtub body placed upside down on the pallet is pressed against the above-mentioned mounting surface using clamps provided on the pallet.

[0005] Patent document 3 describes a method for manufacturing a bathtub, which includes a bathtub body preparation step of preparing a bathtub body formed from thermosetting resin; an insulation material preparation step of preparing an insulation material having an uncured thermosetting resin on its surface; a setting step of setting the bathtub body and the insulation material relative to a holding mold in a state where the outer surface of the bathtub body faces the holding mold via the insulation material; a joining step of joining the bathtub body and the insulation material by contacting them in a state where they are pressed against each other while applying to the insulation material a temperature at which the thermosetting resin hardens; and a demolding step of demolding the bathtub body joined to the insulation material from the holding mold. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-343567 [Patent Document 2] Japanese Patent Application Publication No. 6-343568 [Patent Document 3] Patent Publication No. 2021-30615 Summary of the Invention [Problem to be solved by the invention]

[0007] However, spraying polyurethane foam onto the bathtub body, as in the methods described in Patent Documents 1 and 2, can easily result in inconsistent finishes and unstable heat retention. Also, the method described in Patent Document 3, in which the bathtub body and the insulating material are prepared separately and then pressure-bonded together, requires many steps, resulting in low production efficiency and the risk of the bathtub body deforming inward.

[0008] Therefore, an object of the present invention is to provide a bathtub in which a heat insulating layer is formed on the outer surface of the bathtub body by reaction injection molding of a thermosetting resin composition. [Means for solving the problem]

[0009] The present invention relates to a method for manufacturing a bathtub having a bathtub body and a heat insulating layer formed on the outer surface of the bathtub body, A step of placing the bathtub body on a lower mold having a recess formed along the shape of the outer surface of the bathtub; A step of placing an upper mold having a convex portion formed along the shape of the inner surface of the bathtub body on the bathtub body; Injecting a thermosetting resin composition into a cavity between the lower mold and the bathtub body; forming the heat insulating layer made of a cured product of the thermosetting resin composition on the outer surface of the bathtub body by curing the thermosetting resin composition; have A method for manufacturing a bathtub.

[0010] The present invention provides a bathtub bathtub having a bathtub body and a heat insulating layer made of a thermosetting foam formed on the outer surface of the bathtub body, The foam density of the thermosetting foam is 130 to 190 kg / m 3 is It's a bathtub. Effect of the Invention

[0011] According to the present invention, a bathtub can be provided in which a heat insulating layer is formed on the outer surface of a bathtub body by reaction injection molding a thermosetting resin composition. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic perspective view showing a bathtub according to one embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic cross-sectional view showing a bathtub according to one embodiment of the present invention. [Diagram 3] This is a schematic cross-sectional view showing the state in the middle of arranging the lower mold / bathtub body / upper mold in that order from below in a bathtub manufacturing method according to one embodiment of the present invention. [Figure 4] This is a schematic cross-sectional view showing the state in which a lower mold / bathtub body / upper mold are arranged from below in this order in a bathtub manufacturing method according to one embodiment of the present invention. [Diagram 5] This is a schematic cross-sectional view showing the situation in which an insulating layer is formed in the cavity between the lower mold and the bathtub body in a bathtub manufacturing method according to one embodiment of the present invention. [Figure 6] 1 is a schematic cross-sectional view showing the state in which a bathtub having a bathtub body and an insulating layer is demolded in a bathtub manufacturing method according to one embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A bathtub according to one embodiment of the present invention is shown in Fig. 1 (perspective view) and Fig. 2 (cross-sectional view). As shown in Fig. 1 and Fig. 2, the bathtub 1 has a bathtub body 2 and a heat insulating layer 3 formed on the outer surface of the bathtub body 2.

[0014] The bathtub body 2 generally has a concave tank section 2c for storing hot water inside, and a flange section 2d formed like a canopy extending from the top of the tank section 2c outward. The bathtub body 2 is usually made of fiber-reinforced plastic (FRP), artificial marble, stainless steel, enamel, wood, etc. In particular, since fiber-reinforced plastic or artificial marble has poorer heat retention than other materials, the effect of applying the present invention is great when the bathtub body 2 is made of fiber-reinforced plastic or artificial marble.

[0015] The heat insulating layer 3 is formed on the outer surface 2b of the bathtub body 2, and is made of a cured product of a thermosetting resin composition. The thermosetting resin composition may be any liquid material that can be subjected to reaction injection molding (RIM), and specific examples thereof include a urethane resin composition, an epoxy resin composition, a polyester resin composition, and a phenolic resin composition. From the viewpoint of realizing high heat retention, the cured product of the thermosetting resin composition is preferably a thermosetting foam such as a soft or hard urethane foam or a phenolic foam, and more preferably a hard urethane foam.

[0016] The foam density of the thermosetting foam (particularly rigid polyurethane foam) forming the heat insulating layer 3 is 130 to 190 kg / m 3It is preferable that the foam density of the thermosetting foam is 130 kg / m 3 If the foam density of the thermosetting foam is 190 kg / m or more, the mechanical strength is increased, and the bathtub 1 is less likely to deform due to continuous use. 3 If the density is less than this, the heat insulation property is increased, and the heat retention performance of the bathtub 1 is improved. The foaming density of the thermosetting foam is 155 to 185 kg / m 3 The foam density of the thermosetting foam can be adjusted by the amount of the polyol foam stabilizer in the urethane material.

[0017] Next, steps in a manufacturing method for bathtub 1 according to one embodiment of the present invention will be described with reference to Figs. 3 to 6 (all cross-sectional views).

[0018] First, as shown in Fig. 3 (during arrangement) and Fig. 4 (after arrangement), the lower mold 12 / bathtub body 2 / upper mold 11 are arranged in this order from the bottom. More specifically, the bathtub body 2 is arranged on the lower mold 12, and the upper mold 11 is arranged on the bathtub body 2. Here, the lower mold 12 has a recess 12b on its upper surface that is formed according to the shape of the outer surface 1b of the bathtub 1 that will ultimately be manufactured. Therefore, as shown in Fig. 4, a cavity 13 for forming the insulating layer 3 is formed between the lower mold 12 and the bathtub body 2.

[0019] Meanwhile, the upper mold 11 has a convex portion 11a on its lower surface that is formed along the shape of the inner surface 2a of the bathtub body 2 (= the inner surface 1a of the bathtub 1). In other words, the upper mold 11 and the inner surface 2a of the bathtub body 2 are in contact with each other. This makes it possible to prevent the bathtub body 2 from deforming inward due to the pressure from the thermosetting resin composition when the thermosetting resin composition is injected and cured into the cavity 13 formed between the lower mold 12 and the bathtub body 2.

[0020] The upper mold 11 and the lower mold 12 are dies for reaction injection molding, and may be made of a metal such as aluminum, or may be made of a synthetic resin. The side surface forming the recess 12b of the lower mold 12 may be integrated with the flat surface located below, or may be separate as long as it functions as a die for reaction injection molding. The protrusion 11a of the upper mold 11 may be integrated with the flat surface located above, or may be separate as long as it functions as a die for reaction injection molding.

[0021] The surfaces of the upper mold 11 and the lower mold 12 (particularly, at least the area of ​​the surface of the lower mold 12 that forms the cavity 13) are preferably covered with a composite plating film (not shown). This improves the flow of the thermosetting resin composition when it is injected into the cavity 13, makes the surface of the obtained heat insulating layer 3 less likely to be scratched, and makes it easier to remove the heat insulating layer 3 from the mold. The thickness of the composite plating film is preferably 5 to 20 μm.

[0022] As the composite plating, electroless nickel-PTFE composite plating is preferable. Electroless nickel-PTFE composite plating is so-called Teflon (registered trademark) plating, and a coating is formed in which PTFE (polytetrafluoroethylene) fine particles are uniformly dispersed and co-deposited in an electroless nickel coating. PTFE is a fluororesin (fluorocarbon resin) consisting only of fluorine atoms and carbon atoms, and is chemically stable and has excellent heat resistance and chemical resistance. In addition, each PTFE fine particle is firmly held by the matrix, and since the matrix is ​​made of metal, the adhesion between the base material and the PTFE plating is strong. The content of PTFE in the plating solution is preferably 25 to 40% by volume.

[0023] Furthermore, it is preferable that a thermoplastic resin coating (not shown) made of a styrene-based resin is formed on at least the area of ​​the surface of the lower mold 12 that forms the cavity 13. By doing so, the thermoplastic resin coating is transferred to the surface of the heat insulating layer 3, and the thermoplastic resin coating is easily released from the lower mold 12, eliminating the need to apply a release agent to the surface of the lower mold 12. Of course, a release agent may be applied to the surface of the lower mold 12, but not applying a release agent eliminates the need to degrease the heat insulating layer 3, sand it with emery paper, and correct any pinholes that may occur.

[0024] A preferred method for forming the thermoplastic resin coating is to apply a thermoplastic resin solution in which a styrene-based resin is dissolved in a solvent to at least the region of the surface of the lower mold 12 where the cavity 13 is to be formed, and then dry the lower mold 13 to form the thermoplastic resin coating. The region on which the thermoplastic resin coating is formed by applying the thermoplastic resin solution may be only the region of the surface of the lower mold 12 where the cavity 13 is to be formed, or may be the entire surface of the lower mold 12. The thermoplastic resin coating may also be formed on the surface of the upper mold 11. The thickness of the thermoplastic resin coating is preferably 10 to 100 μm, more preferably 20 to 60 μm.

[0025] Examples of styrene-based resins include polystyrene, styrene-acrylonitrile copolymer resin (SAN resin), acrylonitrile-butadiene-styrene copolymer resin (ABS resin), and acrylonitrile-ethylene-styrene copolymer resin (AES resin), which are easily dissolved in solvents. Among these, ABS resin is preferable, and plating grade ABS resin is more preferable. As the solvent, ketones such as methyl ethyl ketone (MEK) and acetone are preferable because they are easy to dry. The thermoplastic resin solution can be prepared, for example, by dissolving powdered or pelletized ABS resin in MEK. Furthermore, the viscosity of the thermoplastic resin solution can be adjusted by using toluene (thinner) or the like.

[0026] Thereafter, the upper mold 11 and the lower mold 12 are clamped together, and a thermosetting resin composition is injected into the cavity 13 between the lower mold 12 and the bathtub body 2, and the thermosetting resin composition is cured to form a heat insulating layer 3 made of a cured product of the thermosetting resin composition on the outer surface 2b of the bathtub body 2 (FIG. 5). The thermosetting resin composition can be cured, for example, by heating the upper mold 11 and the lower mold 12 with a heating means (not shown). The temperature of the upper mold 11 and the lower mold 12 is preferably 40 to 80°C.

[0027] After that, upper mold 11 and lower mold 12 are opened, and bathtub 1 with heat insulating layer 3 formed on outer surface 2b of bathtub body 2 is removed (Fig. 6). In particular, when a thermoplastic resin coating is formed on at least the area of ​​the surface of lower mold 12 that forms cavity 13, the thermoplastic resin coating is easily released from lower mold 12, so bathtub 1 can be easily removed. After that, deburring is performed as necessary.

[0028] According to the present invention as described above, a bathtub 1 is obtained in which an insulating layer 3 is formed on the outer surface of a bathtub body 2 by reaction injection molding a thermosetting resin composition, thereby preventing the bathtub body 2 from deforming inwardly during molding. EXAMPLES

[0029] <Example 1> A bathtub 1 having the structure shown in Fig. 1 and Fig. 2 was manufactured by the method shown in Fig. 3 to Fig. 6. Specifically, a bathtub body 2 made of artificial marble used in commercially available bathtubs (manufactured by Takara Standard, product name: Keep Clean Bathtub) was prepared as the bathtub body 2, and the bathtub body 2 was placed between an upper mold 11 having a convex portion 11a and a lower mold 12 having a concave portion 12b. A rigid urethane foam concentrate (manufactured by Mitsui Chemicals, product name: Actocol SK-2304 / Cosmonate CG-3200) was then injected and cured into a cavity 13 formed between the lower mold 12 and the bathtub body 2, thereby forming a 20 mm thick heat insulating layer 3 on the outer surface 2b of the bathtub body 2. The foaming density of the rigid urethane foam forming the heat insulating layer 3 was 130 kg / m 3 It was. <Example 2> The foam density of the rigid urethane foam forming the heat insulating layer 3 is 155 kg / m 3 Except for the above, the bathtub 1 was manufactured in the same manner as in Example 1. <Example 3> The foam density of the rigid urethane foam forming the heat insulating layer 3 is 180 kg / m 3 Except for the above, the bathtub 1 was manufactured in the same manner as in Example 1. <Example 4> The foam density of the rigid urethane foam forming the heat insulating layer 3 is 190 kg / m 3 Except for the above, the bathtub 1 was manufactured in the same manner as in Example 1. <Example 5> The foam density of the rigid urethane foam forming the heat insulating layer 3 is set to 200 kg / m 3 Except for the above, the bathtub 1 was manufactured in the same manner as in Example 1. <Comparative Example 1> A bathtub 1 was manufactured in the same manner as in Example 1, except that a flat upper mold 11 without a protruding portion 11a was used. <Comparative Example 2> The bathtub 1 was manufactured by forming a heat insulating layer 3 having a thickness of about 20 mm by spraying a hard urethane foam onto the outer surface 2b of the bathtub body 2. The foam density of the hard urethane foam forming the heat insulating layer 3 was 30 kg / m 3 It was.

[0030] <Deformation of the bathtub body> The bathtubs 1 obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were visually observed to check for the presence or absence of deformation of the bathtub body 2. The results are shown in Table 1.

[0031] <Heat retention test> Bathtubs 1 obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were filled with hot water at about 44°C to a depth of about 70%, covered with a special lid, and left for 20 minutes or more. After that, the water temperature in bathtub 1 was measured 2 hours after it reached 40±2°C, and the temperature change (°C) was calculated. The results are shown in Table 1.

[0032] <Boiling test> Water was poured into the bathtub 1 obtained in Examples 1 to 5 and Comparative Examples 1 and 2 to a depth of about 80%. The water in the bathtub 1 was then poured in and heated with a heater, and maintained at 90°C or higher for 8 hours. Water was added appropriately to keep the water level constant during the maintenance. The hot water in the bathtub 1 was then drained, and the bathtub 1 was left to stand until its temperature returned to room temperature. After 12 cycles of this, the deformation (mm) of the bottom of the bathtub 1 was determined. The results are shown in Table 1.

[0033] [Table 1]

[0034] As described above, in the bathtubs 1 obtained in Examples 1 to 5 using the upper mold 11 having the protrusion 11a, no deformation of the bathtub body 2 was observed, but in Comparative Example 1 using the flat upper mold 11 without the protrusion 11a, deformation of the bathtub body 2 was observed. In addition, when the foaming density of the rigid urethane foam constituting the heat insulating layer 3 was 190 kg / m 3 The bathtubs 1 obtained in the following Examples 1 to 4 had heat retention performance equal to or better than that of the bathtub 1 obtained in Comparative Example 2 in which the heat insulating layer 3 was formed by the conventional spraying method. In addition, the foaming density of the rigid urethane foam constituting the heat insulating layer 3 was 130 kg / m 3 The bathtubs 1 obtained in the above-mentioned Examples 1 to 5 are resistant to deformation in the boiling test, and in particular, the foaming density of the rigid urethane foam constituting the heat insulating layer 3 is 155 kg / m 3 Bathtubs 1 obtained in Examples 2 to 5 described above were less susceptible to deformation in the boiling test, compared to bathtub 1 obtained in Comparative Example 2 in which the heat insulating layer 3 was formed by the conventional spraying method. [Explanation of symbols]

[0035] 1 Bathtub 1a Inner surface 1b Outer surface 2 Bathtub body 2a Inner surface 2b Outer surface 2c Bathtub section 2d Flange part 3. Insulation layer 11 Upper mold 11a Convex part 12 Lower mold 12b Recess 13 Cavity

Claims

1. A method for manufacturing a bathtub having a bathtub body and a heat insulating layer formed on an outer surface of the bathtub body, comprising the steps of: A step of placing the bathtub body on a lower mold having a recess formed along the shape of the outer surface of the bathtub; A step of placing an upper mold having a convex portion formed along the shape of the inner surface of the bathtub body on the bathtub body; Injecting a thermosetting resin composition into a cavity between the lower mold and the bathtub body; forming the heat insulating layer made of a cured product of the thermosetting resin composition on the outer surface of the bathtub body by curing the thermosetting resin composition; have How to manufacture a bathtub.

2. The cured product of the thermosetting resin composition is a thermosetting foam. A method for manufacturing the bathtub according to claim 1.

3. The foam density of the thermosetting foam is 130 to 190 kg / m ３ is A method for manufacturing the bathtub according to claim 2.

4. The thermosetting foam is a rigid urethane foam. A method for manufacturing a bathtub according to claim 2 or 3.

5. applying a thermoplastic resin solution obtained by dissolving a styrene-based resin in a solvent to at least an area of ​​the surface of the lower mold where the cavity is to be formed; drying the lower mold to form a thermoplastic resin coating; Further having A method for manufacturing the bathtub according to claim 1.

6. The styrene-based resin is polystyrene, a styrene-acrylonitrile copolymer resin (SAN resin), an acrylonitrile-butadiene-styrene copolymer resin (ABS resin), or an acrylonitrile-ethylene-styrene copolymer resin (AES resin). A method for manufacturing the bathtub according to claim 5.

7. A bathtub body and a heat insulating layer made of a thermosetting foam formed on the outer surface of the bathtub body, The foam density of the thermosetting foam is 130 to 190 kg / m ３ is Bathtub.

8. The thermosetting foam is a rigid urethane foam. The bathtub according to claim 7.

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