JP2002225055A - Bathtub made of artificial marble and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bathtub made of artificial marble which can be formed inexpensively by reducing the generation of defective molding even when it has horizontal surfaces different in height, and to provide a method for producing the bathtub. SOLUTION: A molding material 100-500 joules in flow resistance energy is subjected to heating compression molding. The molding material is formed, for example, from BMC and has prescribed flow resistance energy by at least one means selected from a means for changing the composition of a resin, a means for adjusting the kind and quantity of an additive, and a means for adjusting the water content of the additive, and other means. The bathtub is formed by a bathtub for half the body bathing, and has two approximately horizontal surfaces different in height in its bottom part. The areas of the surfaces are set in a prescribed ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial marble bathtub used for, for example, a bathtub for a half-body bath and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, such artificial marble is SM
It is manufactured by heat compression molding C (sheet molding compound) or BMC (bulk molding compound). Conventionally, in order to suppress the occurrence of pinholes and the like at the time of heat compression molding and increase the orthogonality of the molded product, for example, a method of searching for the optimum conditions by trial and error (referred to as method 1), and a method disclosed in As disclosed in Japanese Patent Application Laid-Open No. 95023, a method of logically setting molding conditions (referred to as Method 2), or Japanese Patent Application Laid-Open Nos. 5-43671, 5-330884, and 5-230
As disclosed in JP-A-357-357 and JP-A-9-302009, a method of obtaining various properties such as a predetermined viscosity increase by changing the composition (referred to as method 3) has been proposed.

Another method is disclosed in, for example,
As shown in JP-B-183808, a method (hereinafter referred to as method 4) using an unsaturated polyester molding compound for heat compression molding artificial marble containing silica powder and a fiber reinforcing material has been proposed.

However, in the case of the above methods 1 to 3, the SMC
And the period from when BMC is manufactured until it becomes a molded product,
Since it takes 30 to 90 days if it is fast and one day is long, the hardness and fluidity of the material of SMC and BMC itself change with time depending on the storage period from the time of manufacture of the material to the molding, and the optimal molding It is difficult to unconditionally set conditions and an optimum material composition, and it is difficult to obtain a molded article having stable appearance quality (for example, no pinholes are generated).

[0005] In the case of method 4, since silica powder is added in order to make the stone-like pattern uniform, a hot water attack (stimulation) is applied to a molded product requiring hot water resistance such as a bathtub. As a result, the silica powder is peeled off or missing, and has a disadvantage that it is likely to appear as whitening on the surface of the molded product for a long-term use. In addition, in the case of this method 4, if crushed rocks and mica are included,
Since the hardness of the crushed material itself is high, the wear of the layer such as hard chrome plating of the mold is accelerated, and the mold life is shortened,
There is also an inconvenience that the maintenance cost of the mold tends to increase, such as a replating cost.

Accordingly, the present applicant has filed an artificial marble disclosed in Japanese Patent Application No. 2000-273122 to solve these disadvantages. This artificial marble is obtained by subjecting a molding material (molding compound) containing a thickener, a crushed resin, and a fiber reinforcing material to a resin, which does not contain silica powder, to be subjected to heat compression molding.

[0007]

However, in the case of this artificial marble, when the molded product is a general bathtub 101 whose bottom 101a is substantially flat as shown in FIG. The occurrence of poor appearance due to a water attack can be reduced. However, according to subsequent research, when the artificial marble was applied to a bathtub for a half-body bath, which has recently been receiving attention as a bathing method for reducing the burden on the heart during bathing, molding defects occur on the inner surface of the bathtub. The problem that it is easy was clarified.

That is, in the case of a bathtub for a half-body bath, as shown in FIG.
The BMC 7 is placed on the horizontal surface 8a of the core die 8 corresponding to the lower horizontal surface having a lower height, and the mold die 9 is lowered by heating and compressing since the two horizontal surfaces having two horizontal water gradients are provided. When the molding is performed, the flow path (flow path) of the BMC 7 is temporarily narrowed when the BMC 7 passes through the lower vertical surface 8c. Then, when the BMC 7 reaches the horizontal surface 8b of the core die 8 corresponding to the upper horizontal surface having a higher height, the flow path becomes wider and reaches the next upper vertical surface 8d.
The air entrained in C7 or at the time of its distribution loses its escape. As a result, molding defects such as pinholes due to air are likely to occur on the inner surface (particularly, the vertical surfaces 8c and 8d and the horizontal surface 8b) of the molded product (bathtub).

Therefore, in order to prevent this molding defect,
As shown in FIG. 5, two different horizontal surfaces 8 of the core mold 8 are provided.
It is conceivable to place the BMCs 7a and 7b divided into a and 8b, respectively, and heat-compress them. In this case,
For example, it is difficult to suppress the occurrence of molding defects in the molded article, such as the BMCs 7a and 7b divided at the x-marked portions in the figure collided with each other and welds generated.

In other words, when a bathtub for a half-body bath having two horizontal planes is heated and compression-molded using BMC7 or the like as a molding material, it is fundamental to flow BMC7 in a direction in which the flow path becomes narrow. A major issue is how to expel air contained and air entrained during molding smoothly. In addition, if a defect occurs on the inner surface of the bathtub, the bathtub itself is attacked with hot water, so that it is difficult to repair molding defects in terms of durability and defective molding products are actually discarded. From these facts, the reality is that the appearance of a bathtub (particularly, a bathtub for a half-body bath) that can simultaneously reduce molding defects and reduce costs is desired.

The present invention has been made in view of such circumstances, and has as its object to reduce the occurrence of molding defects and reduce the cost of forming a bathtub even in bathtubs having horizontal surfaces having different heights. To provide a marble bathtub. Another object of the present invention is to provide a method of manufacturing an artificial marble bathtub that can be formed at low cost by reducing the occurrence of molding defects even in bathtubs having horizontal surfaces having different heights.

[0012]

Means for Solving the Problems To achieve the above object, the invention according to claim 1 of the present invention is characterized in that a molding material having a flow resistance energy of 100 to 500 joules is formed by heating and compression molding. I do. The molding material is formed of BMC, as in the second aspect of the invention, and is formed by at least one means such as changing the composition of the resin, adjusting the type and amount of the additive, and adjusting the moisture of the additive. It preferably has a predetermined flow resistance energy. Also,
The artificial marble bathtub is formed of a bathtub for a half-body bath, has two substantially horizontal surfaces of different heights at the bottom, and the area ratio is set to a predetermined ratio. Is preferred.

[0013] With this configuration, the artificial marble bathtub is formed by setting a molding material such as BMC between the molds and performing heat compression molding. At this time, since the flow resistance energy of the molding material is set to 100 to 500 joules by changing the composition of the resin or the like, the fluidity of the molding material at the time of molding is secured to a predetermined value, and a plurality of horizontal surfaces are formed. Even a bathtub for a half-body bath has a large force to expel air contained in the molding material itself or air entrained during molding out of the mold. This allows
Generation of molding defects due to air or the like is reduced, and an artificial marble bathtub or the like for a half-body bath is formed at low cost.

The invention according to claim 4 is characterized in that a molding material having a flow resistance energy of 100 to 500 joules is prepared, the molding material is set between a pair of dies, and is subjected to heat compression molding. And It is preferable that the mold is heated and compression-molded with the mold on the surface side of the molded product facing downward, as in the invention of the fifth aspect.

With this configuration, a molding material whose flow resistance energy is set to a predetermined value in advance is prepared, and this is set between a pair of molds and heated and compression-molded. An artificial marble bathtub is formed. At this time, the flow resistance energy of the molding material is
Since the flow rate is set to 100 to 500 joules, which can ensure a predetermined fluidity, the molding material itself and air entrained at the time of molding can be satisfactorily expelled out of the mold, and the occurrence of molding defects is reduced and the cost is reduced. An artificial marble bathtub is obtained. In particular, of the pair of molds, by positioning the mold on the surface side of the molded product on the lower side, the molding material is filled from the surface side of the molded product, and the occurrence of defects on the surface side of the artificial marble bathtub is more. It is surely reduced.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show a case where the artificial marble bathtub according to the present invention is applied to a bathtub for a half body bath. FIG. 1 is a plan view thereof, and FIG. 2 is a half sectional view thereof. 4 and 5 are denoted by the same reference numerals and described.

In FIGS. 1 and 2, a bathtub 1 for a half-body bath is formed of artificial marble by a method described later.
It has a bottom 2 and a top flange 3. The bottom 2
The first horizontal surface 2a is formed by a first horizontal surface 2a having a low height and a second horizontal surface 2b as a bench for a half-body bath.
A first vertical surface 4a inclined at a predetermined angle is provided between the first vertical surface 4a and the second horizontal surface 2b. A second vertical surface 4a inclined at a predetermined angle is provided between the second horizontal surface 2b and the upper surface flange 3.
b is provided.

The first horizontal surface 2a is provided with a drain hole 5 and a number of slip stoppers 6 integrally formed in a predetermined pattern. The upper flange portion 3 includes an overflow portion 3a for overflowing hot and cold water in the bathtub 1 to a washing place, and a washing place side flange portion 3b.
And a depth side flange portion 3c located on a wall panel side (not shown).

The bathtub 1 is a BMC 7 (FIG. 4) as a molding material composed of a resin made of a thermoplastic resin or a thermosetting resin, and various additives added to the resin in a predetermined weight part. ) Is formed by heat compression molding. At this time, the flow resistance energy of the BMC 7 is set to 100 to 500 joules (J). As the resin component of the BMC 7, an unsaturated polyester resin is preferable, but various resins such as a vinyl ester resin, an epoxy resin, and an acrylic resin, and a mixture thereof are used.

Further, as the additive, a crushed resin for decoration, a low shrinkage agent, a thickener, a filler, a fiber reinforcing material and the like are used. Among them, as the resin crushed material, for example, two types of resin particles A and B shown in Table 1 below (JP-A-59-3)
This mixture was inserted into cellophane to form a plate having a thickness of 3 mm, cured by heating in an oven at 60 ° C. for 1 hour, and then peeled off the cellophane, and then ground with a hammer mill. Then, for example, 2
It is formed by using particles of 0 to 80 mesh.

The crushed resin material is mixed with the resin 10
1 to 200 parts by weight (preferably 3 to 5 parts by weight)
0 parts by weight, more preferably 20 to 30 parts by weight). The particle size of the crushed resin (particle size of individual particles)
Is, for example, 0.05 to 3 mm (preferably 0.15 to 1.
(0 mm, more preferably 0.6 to 1.0 mm) is used.

[0022]

[Table 1]

As the low-shrinkage agent, for example, a crosslinked polystyrene-based low-shrinkage agent is used and added in an amount of 5 to 20 parts by weight, and as the thickener, for example, magnesium oxide is used and 1.5 to 10 parts by weight. Parts by weight (preferably 1.5 to
4.5 parts by weight). Further, examples of the fiber reinforcing material include inorganic fibers such as glass fiber and asbestos fiber, and organic fibers such as vinylon and nylon.
The fiber length is about 0.5-6 mm (preferably 1-2 m
m), the amount is set to about 1 to 15% by weight (preferably 2 to 10% by weight) of the whole.

The flow resistance energy of the BMC 7 can be determined by changing the composition of the resin (selection of type, adjustment of parts by weight, etc.),
By adopting at least one of various adjusting means such as selection of kinds of various additives (including fiber reinforcing materials), increase / decrease of added parts by weight (amount) and activity control, moisture control of fillers and fiber reinforcing materials, It is set to 100-500J. The flow resistance energy of BMC7 is shown in Table 2 below.
Is a value measured by the method shown in FIG.

[0025]

[Table 2]

[0026]

Next, examples according to the present invention and comparative examples will be described. First, BMCs 7 composed of the compositions shown in Examples 1 and 2 and Comparative Examples 1 to 4 shown in Table 3 below were prepared, the flow resistance energy was set to a predetermined value, and the postures of the core type and the mold type were set to predetermined values. Set to. Then, the core mold temperature was 115 ° C., the mold temperature was 135 ° C., the molding pressure was 1400 tons, the molding time was 8 minutes, and the BMC
7 was set to the state shown in FIG. 4, and the bathtub 1 having the shape shown in FIGS. 1 and 2 was formed under the condition that the charge rate was 20% of the projected area.

The external dimensions of the bathtub 1 are L = 16
00 mm, W = 750 mm, height H = 500 mm, the depth dimension of the slip stopper 6 is 0.5 mm, and the area S1 of the first horizontal surface 2a is about 450 × 300 m
m and the area S2 of the second horizontal plane 2b is 200 × 300 m
m, that is, the area ratio was set to S1: S2 = about 9: 4.

[0028]

[Table 3]

As apparent from Table 3, Examples 1 and 2 in which the flow resistance energy of the BMC 7 was set to 100 to 500 J and the core type on the product surface side was at the lower side.
No pinholes or the like were found on the inner surface 1a (see FIGS. 1 and 2), and the bathtub 1 having a uniform stone-grain pattern and good hot water resistance was obtained.

On the other hand, in Comparative Examples 1 and 2 in which the core type was turned upward with BMC 7 having the same composition (the same flow resistance energy) as in Examples 1 and 2, pinholes and the like were formed on the inner side surface 1a of the bathtub 1. The occurrence of defects was observed, and the bathtub 1 having poor hot water resistance was obtained. Also, in Comparative Examples 3 and 4 in which the flow resistance energy of the BMC 7 was set to 50 J and 700 J, occurrence of molding defects was observed on the inner surface 1 a of the bathtub 1. In the comparative examples 1 and 2, the occurrence of the inner surface defect was determined to be “present”. Level).

Bathtub 1 in these comparative examples 1 to 4
It is considered that the pinholes and the like on the inner side surface 1a are caused when the BMC 7 does not flow uniformly along the mold when the BMC 7 flows. In particular, when the flow resistance energy of the BMC 7 is too small as in Comparative Example 3, the force for expelling air is small and defects are likely to occur. Conversely, when the flow resistance energy is too large as in Example 4, the BM
The fluidity of the C7 in the mold is deteriorated, and the air entrained during the flow is rather increased, so that defects are likely to occur.

Table 3 shows the case of the bathtub 1 for a half-body bath having two horizontal surfaces 2a and 2b on the bottom 2 thereof. The bathtub 101 shown in FIG. It has been confirmed that results can be obtained.

As described above, in the bathtub 1 formed by using the BMC 7 shown in the first and second embodiments as the molding material, no molding defects such as pinholes are generated on the inner side surface 1a, and good appearance quality is obtained. In addition, a uniform stone-like pattern can be obtained, and good results can also be obtained in terms of the appearance of a lame tone and the transparency of the product surface. Further, it is excellent in hot water resistance and can suppress occurrence of poor appearance such as whitening even when hot water is attacked.

Further, even if the bathtub 1 for a half-body bath has a first horizontal surface 2a and a second horizontal surface 2b on the bottom 2,
Since molding defects that easily occur on the inner side surface 1a such as the first horizontal surface 2a can be reduced, the orthogonality can be increased. Furthermore, since a BMC 7 of 100 to 500 J is prepared as a molding material and can be molded by heating and compressing it with a core mold and a mold, it can be easily handled without changing existing manufacturing and maintenance. from these things,
The manufacturing cost can be reduced, and a low-cost, high-quality bathtub 1 for a half-body bath, which has conventionally been difficult, can be easily obtained.

Further, according to the present invention, the following additional effects can be obtained. In other words, since the pre-cured resin crushed material is added at a certain appropriate ratio, the resin crushed material itself acts as a low shrinkage agent for suppressing the shrinkage of the cured product, and is formed during molding and curing. The shrinkage of the product can be kept low, and the occurrence of cracks and the like during molding can be prevented. Also, by mixing the resin crushed material having a particle size in a predetermined range with the resin component, it becomes difficult to visually distinguish the foreign matter mixed in the resin component from the resin crushed material. Is reduced, and the traverse rate of the bathtub 1 can be further increased.

In each of the above embodiments, the case where the molding material is BMC 7 has been described. However, it is easily assumed that the same result can be obtained also with respect to the SMC. The same effect can be expected even when the water gradient of the second horizontal plane 2b is set to 30 degrees or less.

[0037]

As described above in detail, according to the first aspect of the present invention, since the heat compression molding is performed using a molding material having a flow resistance energy of 100 to 500 joules, the molding material is formed along the mold. An evenly inexpensive artificial marble bathtub that can be made to flow evenly and favorably to expel air entrained in the molding material or at the time of molding and that reduces the occurrence of molding defects can be easily obtained.

According to the second aspect of the present invention, in addition to the effects of the first aspect, BMC as a molding material
The flow resistance energy of the BMC can be easily set to a predetermined value because a predetermined flow resistance energy can be obtained by at least one means such as changing the composition of the resin, adjusting the type and amount of the additive, and adjusting the moisture of the additive. Thus, a cheaper artificial marble bathtub can be obtained.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect, the artificial marble is formed of a bathtub for a half-body bath having two horizontal planes having different heights at its bottom. In addition, since the area ratio of each horizontal plane is set to a predetermined ratio, an artificial marble bathtub for a half-body bath can be formed at lower cost and with higher quality.

According to the fourth aspect of the present invention, a molding material having a flow resistance energy of 100 to 500 joules is prepared, and is set between a pair of molds to be subjected to heat compression molding. It can be made to flow evenly and well along the mold, and the air entrained in the molding material and at the time of molding can be reliably expelled, so that an inexpensive artificial marble bathtub with reduced occurrence of molding defects can be easily obtained. .

According to the fifth aspect of the present invention, in addition to the effect of the fourth aspect of the present invention, in addition to the effect of the fourth aspect of the present invention, the compression molding is performed with the mold on the surface side of the molded product facing downward, so that the molded product can be formed from the surface side. The molding material can be filled, and the effect of being able to more reliably reduce the occurrence of defects on the surface side of the artificial marble bathtub is achieved.

[Brief description of the drawings]

FIG. 1 is a plan view of a bathtub for a half-body bath to which an artificial marble bathtub according to the present invention is applied.

FIG. 2 is a half sectional view of the same.

FIG. 3 is a plan view of a general bathtub.

FIG. 4 is an explanatory view of a conventional molding method.

FIG. 5 is an explanatory view of another conventional molding method.

[Explanation of symbols]

 1 Bathtub 1a Inner surface 2 Bottom 2a First horizontal plane 2b ... Second horizontal plane 3...... Top flange 4a. Drainage hole 6 ・ ・ ・ ・ ・ ・ ・ Slip stop 7 ・ ・ ・ ・ ・ ・ ・ BMC 8 ・ ・ ・ ・ ・ ・ ・ Core type 9

Claims (5)

[Claims] 1. An artificial marble bathtub obtained by heating and compressing a molding material having a flow resistance energy of 100 to 500 joules. 2. The method according to claim 1, wherein the molding material is formed of BMC and has a predetermined flow resistance energy by at least one of means such as changing the composition of the resin, adjusting the type and amount of the additive, and adjusting the moisture of the additive. The artificial marble bathtub according to claim 1, characterized in that: 3. The artificial marble bathtub is formed of a bathtub for a half-body bath, has two substantially horizontal surfaces having different heights at the bottom thereof, and has an area ratio set to a predetermined ratio. The artificial marble bathtub according to claim 1 or 2, wherein: 4. Manufacture of an artificial marble bathtub, characterized in that a molding material having a flow resistance energy of 100 to 500 joules is prepared, the molding material is set between a pair of molds and heated and compression molded. Method. 5. The heating and compression molding of the pair of dies, with the dies on the surface side of the molded product facing downward.
The method for producing the artificial marble bathtub described in the above.