JP2007055103A - Method for producing artificial marble - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing artificial marble which dissolves an air gathering phenomenon in the vicinity of an air extraction opening and suppresses a defect in the appearance, a deterioration in the performance, the molding distortion, and the warpage of a molding when the molding is produced by using a casting mold. <P>SOLUTION: In the method for producing the artificial marble, a resin composition 7 in which additives including a filler, an internal releasing agent, a curing agent, and a pattern material expressing an artificial marble pattern are added into a thermosetting resin is prepared, injected from the inlet 2 of the casting mold 1 into an injection space part 4 while air gathering in the injection space part 4 is discharged from the air extraction opening 3, heated, and cured. While an air permeable structure S which can prevent the permeation of the resin composition 7 is stuck provisionally on the inner surface of the injection space part 4 to cover the end part 3a on the injection space part 4 side of the air extraction opening 3, the resin composition 7 is injected into the injection space part 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing artificial marble used as a member of furniture or housing equipment, or a building material.

Conventionally, by injecting a resin composition containing additives such as a filler, an internal mold release agent, a curing agent, and a pattern material into a thermosetting resin into a desired casting mold, and heating and curing the resin composition. It is known to form artificial marble moldings.
As thermosetting resin that is a raw material for producing artificial marble, unsaturated polyester resin, vinyl ester resin, thermosetting acrylic resin, epoxy resin, etc. are used. Widely used as furniture, housing equipment, and building materials such as kitchen counters, bathtubs, and washbasins.

4 (a) and 4 (b) are cross-sectional views showing a conventional method for producing artificial marble as described above. Here, the molding process of the bathtub is shown as an example, and it is molded in a state that is upside down from the state of being installed in the bathroom.
The mold 100 including the upper mold 100a and the lower mold 100b is imitated in the shape of a desired bathtub, and the thickness of the bathtub is adjusted by a gasket G interposed between the upper mold 100a and the lower mold 100b. Is done.
The inlet 200 is provided at the lowest position where the resin composition 700 should be filled, and the air vent 300 is provided at the highest position corresponding to the center of the bottom of the bathtub and filled with the resin composition 700. Is provided. The resin composition 700 is filled into the injection space 400 of the mold 100 from the injection port 200 via the resin injection pipe 500 from the resin pressure injection device 600, and the air in the mold 100 is blown by the injection pressure. While exhausting from the air vent 300, the mold 100 is gradually filled from the lower surface to the upper surface.
Patent Document 1 below discloses a manufacturing method for manufacturing a molded product of artificial marble by the same manufacturing method as described above.
JP 2002-001740 A

  However, according to the above-described method, the resin composition 700 is injected, and in the final stage where the resin composition 700 reaches from the lower surface portion to the upper surface portion (corresponding to the bottom portion of the bathtub), air is still discharged from the air vent 300. While the exhaust cannot be completed, the resin composition 700 may reach the air vent end portion 300a. In such a case, if the air remaining in the vicinity of the air vent port end portion 300a cannot be exhausted and the air vent port end portion 300a is covered with the resin composition 700, air bubbles A can be formed in the resin composition 700. There has been a problem that “air accumulation” occurs and the resin is heated and cured as it is to become a molded product (that is, a product). In particular, when the injection speed is increased by increasing the degree of pressurization when injecting the resin composition 700 into the mold 100, the air entrainment in the injection space 400 becomes more intense and there are many "air pools". Generated and a good molded product could not be obtained.

The occurrence of such “air accumulation” is a phenomenon that occurs inside the mold 100 in the manufacturing stage, and it is difficult to confirm the state by visual observation or other methods. This is the first time that a molded product is taken out. In addition, when the bubbles A are not on the surface of the molded product, there is no way to confirm the occurrence of “air accumulation” itself.
However, when “air accumulation” occurs, the vicinity of the bubble A is an air gap, so that the thermal conductivity is lowered when heat-curing. As a result, there is a difference in the curing history between the part where there is no “air accumulation” and the part, which affects the performance of the molded product, the impact strength is reduced due to the occurrence of molding distortion, warpage and dimensional defects. This often occurs and is a big problem.
As described above, there is an urgent need to eliminate the “air pool” phenomenon, which has a great influence on the characteristics of a molded product and is defective in appearance.

  The present invention has been made in view of the above circumstances, and when producing a molded product using a casting mold, eliminates the phenomenon of air accumulation near the air vent and eliminates the appearance defects and performance of the molded product. An object of the present invention is to provide a method for producing an artificial marble with little reduction and less molding distortion and warpage.

  The method for producing artificial marble according to claim 1 provides a resin composition in which a thermosetting resin is blended with additives such as a filler, an internal mold release agent, a curing agent, and a pattern material expressing an artificial marble pattern. The artificial marble produced by injecting the resin composition from the injection port of the casting mold into the injection space portion while injecting air accumulated in the injection space portion through the air vent and heat curing. In the manufacturing method, in a state where the breathable structure capable of preventing the permeation of the resin composition is temporarily attached to the inner surface of the injection space so as to cover the injection space side end of the air vent, the injection The resin composition is injected into the space.

  In the method of manufacturing an artificial marble according to the invention of claim 2, the structure is a porous material such as a mat, cloth, sheet, or mesh, and the thickness of the structure is determined by the resin composition. It is characterized in that it is set to be ½ or less of the thickness of a molded product obtained by injection-hardening a product. Examples of the structure include felt and nonwoven fabric. According to a third aspect of the present invention, there is provided a method for producing an artificial marble, wherein the structure is integrated in a molded product obtained by injecting and curing a resin composition. Furthermore, as described in claim 4, after the injection of the resin composition into the casting mold is completed, the injection pressure is increased and the resin composition is infiltrated and impregnated within the thickness of the structure to heat cure. Thus, a molded product is obtained by integrating the structural bodies.

  And in this invention, the particle size of a filler can be 1-100 micrometers like Claim 5, and the ratio of the said filler is the heat | fever which comprises the said resin composition like Claim 6. It can be 0.1-400 weight part with respect to 100 weight part of curable resin. As in claim 7, the viscosity of the resin composition can be 50 to 150,000 mPa · s.

According to the method for manufacturing the artificial marble according to claim 1, since the structure is installed so as to cover the injection space portion side end of the air vent, the air in the injection space is exhausted from the air vent. However, since the resin composition can be injected and filled into the injection space without allowing the resin composition to enter the air outlet side, at the final stage of the resin composition injection, air is supplied to the air outlet. There is no case where the resin composition reaches first and the air vent is covered with the resin composition. Therefore, no air residue is generated at the air vent and the occurrence of air accumulation in the molded product can be prevented.
Therefore, it is possible to produce molded products with little deterioration in performance such as appearance defects and strength reduction of molded products, and less molding distortion and warpage. Besides bathtubs, wash counters, kitchen counters, wash bowls, wall materials, floors This makes it easy to commercialize materials and furniture surface materials.

According to the method for producing artificial marble according to claim 2, the structure can be made into a mat shape, a cloth shape, a sheet shape, a mesh shape, or the like, so that it is not necessary to use a special material. .
Moreover, since the thickness of the structure is set to be ½ or less of the thickness of the molded product obtained by injecting and curing the resin composition, the molded product is prevented from cracking due to the presence of the structure. Can do. If the thickness of the structure is ½ or more of the thickness of the molded product, the notch effect (decrease in strength) of the boundary surface increases, and when the stress is concentrated, the boundary surface becomes the starting point of crack generation, and molding is performed. Product cracks tend to occur.

  According to the method for manufacturing artificial marble according to claim 3, since the structure is integrated with the molded product obtained by injection-curing the resin composition, it is temporarily placed on the casting mold side at the time of demolding. The stuck structure does not remain, and in the next molding step after demolding, the troublesome work of removing the structure clogged with the resin composition from the mold is unnecessary, and a new structure is placed in a predetermined part. It is possible to shift to the next molding process simply by temporarily sticking to the substrate, and efficient production can be achieved.

  According to the method for manufacturing artificial marble according to claim 4, since the molded product is heat-cured in a state where the resin composition is infiltrated and impregnated within the thickness of the structure, the structure is installed in the molded product. The difference in heat conduction between the vicinity and the place where the structure is installed and the influence of curing inhibition can be reduced, and a molded product with a more uniform quality can be obtained. In addition, the structure is firmly integrated with the molded product, and does not remain on the mold side more reliably at the time of demolding.

According to the method for producing artificial marble according to claim 5, the particle size of the filler can be set to 1 to 100 μm.
As the particle size of the filler is smaller, the impact strength of the artificial marble can be improved. However, when the particle size of the filler is smaller than 1 μm, the viscosity of the resin composition increases rapidly, and the dispersibility and fluidity are increased. , The normal injection into the mold cannot be performed, and the manufacturing tends to be difficult. When the particle size of the filler is larger than 100 μm, the viscosity of the resin composition is lowered and there is no problem in production, but the impact strength of the artificial marble tends to be lowered.

According to the method for manufacturing artificial marble according to claim 6, the ratio of the filler can be 0.1 to 400 parts by weight with respect to 100 parts by weight of the thermosetting resin constituting the resin composition. .
When the ratio of the filler is less than 0.1 parts by weight, effects such as imparting a texture due to the addition of the filler, improving heat resistance, and increasing the hardness tend to be small. On the other hand, when the ratio of the filler is larger than 400 parts by weight, the effects of imparting texture, improving heat resistance and increasing the hardness by adding the filler can be obtained, but the viscosity of the resin composition rapidly increases and dispersibility is increased. In addition, fluidity is lowered, normal injection into the mold cannot be performed, and manufacturing tends to be difficult.

According to the method for producing artificial marble according to claim 7, the viscosity of the resin composition can be set to 50 to 150,000 mPa · s.
If the viscosity of the resin composition is less than 50 mPa · s, the time required for heat curing after filling the casting mold with the resin composition and the resin composition soaks into the structure. The body tends to be unable to prevent the resin composition from entering the air vent side. If it is larger than 150,000 mPa · s, it becomes difficult to inject the resin composition into the mold, and the structure is installed without exhausting the air and without allowing the resin composition to enter the air vent side. Even if an attempt is made to inject and fill the resin composition into the injection space to prevent the occurrence of air accumulation, it is difficult to remove the bubbles.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1A to 1C are cross-sectional views showing the manufacturing method of the present invention, FIG. 2 is an enlarged view of a portion X in FIG. 1C, and FIG. 3 is manufactured by the manufacturing method of the present invention. It is a perspective view which shows a bathtub (molded article).

  In the figure, 1 is a casting mold configured by combining an upper mold 1a and a lower mold 1b, 2 is an inlet for injecting the resin composition 7, 3 is an air vent, 3a is an end of the air vent, 4 is an injection space part, 5 is a resin injection pipe, 6 is a resin pressure injection device, 7 is a thermosetting resin with a filler, an internal release agent, a curing agent, and a pattern material expressing an artificial marble pattern. S is a resin structure 7 that prevents permeation of the resin composition 7 and has air permeability, G adjusts the thickness of the bathtub B, and is injected from the injection port 2 As an example, a gasket B for preventing leakage of air and inflow of air is shown as a bathtub manufactured as a molded product. As shown in FIGS. 1A to 1C, in the manufacturing method of the present invention, the resin composition 7 is injected from the inlet 2 into the injection space 4 of the mold 1 as in the conventional example (FIG. 4). For filling, a resin pressure injection device 6 provided through a resin injection pipe 5 is provided.

  The present invention prepares a resin composition 7 in which additives such as a filler, an internal mold release agent, a curing agent, and a pattern material expressing an artificial marble pattern are blended with a thermosetting resin as described above, and the resin composition In the manufacturing method of artificial marble, an object is injected from the injection port 2 of the mold 1 to the injection space portion 4 while exhausting the air accumulated in the injection space portion 4 from the air vent port 3 and heated and cured. In a state where the structure S is temporarily attached to the inner surface of the injection space portion 4 so as to cover the end portion 3a on the injection space portion 4 of the air vent port 3, the resin composition 7 is injected into the injection space portion 4. It is characterized by this.

  An injection port 2 is provided at the lowest position where the resin composition 7 should be filled, and corresponds to the center of the bottom surface of the bathtub B, and the upper mold of the highest mold 1 where the resin composition 7 is filled. An air vent 3 is provided on the 1a side. The injection space part 4 is covered so as to cover the end part of the air release port 3 on the injection space part 4 side, that is, an appropriate range where generation of air remaining is expected (in the example shown, centering on the air discharge port end part 3a). A structural body S is temporarily attached to the inner surface of 4 in advance.

The structure S has a mat shape, a cloth shape, a sheet shape, a mesh shape, etc., and does not allow the resin composition 7 to permeate, but can be used as long as it has a function of allowing air to pass through (air permeability). The type and form are not particularly limited. For example, felt or nonwoven fabric.
Further, the thickness of the structure S is set to be ½ or less of the thickness of a molded product obtained by injecting and curing the resin composition 7. This is to prevent the molded product from cracking due to the presence of the structure S. When the thickness of the structure S is set to 1/2 or more of the molded product thickness, the notch effect (strength reduction) of the boundary surface becomes large, and when the stress is concentrated, the boundary surface becomes a starting point of occurrence of cracks, It tends to cause cracks in the molded product.
The shape, size, and the like of the structure S are not particularly limited, and the attaching method or fixing method for temporarily attaching the structure S is not particularly limited.
For example, the structure S has a shape and size that covers and covers the shape and size of the air vent 3, and uses a double-sided tape, an adhesive tape, or the like as appropriate, and the air vent end 3 a. The structure S is temporarily attached.

After the structure S is temporarily attached to the air vent end 3a in this way (the state shown in FIG. 1 (a)), the resin composition 7 is supplied from the resin pressure injection device 6 to the resin injection pipe 5. The resin composition 7 is gradually filled from the injection port 2 into the injection space portion 4 (from the lower surface portion to the upper surface portion of the mold 1) through (FIG. 1B), and the injection space portion 4 is filled. While the air is exhausted from the air vent 3 through the structure S, the resin composition 7 is filled until the resin composition 7 reaches the upper surface of the mold 1. After the injection of the resin composition 7 into the injection space 4 is completed, the injection pressure is increased and the resin composition 7 is heat-cured in a state where the resin composition 7 is infiltrated and impregnated into the thickness of the structure S. By doing so, the structure S is integrated with the molded product (see FIG. 2).
Therefore, according to this manufacturing method, in the final stage where the resin composition 7 reaches from the lower surface portion to the upper surface portion (corresponding to the bottom portion of the bathtub), the air is still not exhausted from the air vent 3. Since the resin composition 7 does not reach the mouth end 3a, it is possible to prevent the occurrence of “air accumulation”.
Here, in the temporary sticking, the molded product and the structure S are integrated and removed from the mold 1 in the molding and curing process, and therefore, if the adhesive force is too strong, there is a possibility that the mold 1 cannot be removed. It is required to use an appropriate adhesive force from both sides of fixing the structure S and taking out the molded product.

As the thermosetting resin constituting the resin composition 7 of the present invention, one kind or a mixture of two or more kinds of unsaturated polyester resins, vinyl ester resins, thermosetting acrylic resins, or epoxy resins can be used.
Unsaturated polyester resins are synthesized by the condensation reaction of unsaturated dibasic acids such as maleic anhydride and saturated dibasic acids such as phthalic anhydride and glycols, and have unsaturated bonds and ester bonds in the molecule. I have it.
In general, this resin may be one in which a styrene monomer, an acrylic monomer or the like is blended as a crosslinking agent, but the form is not particularly limited.

As the vinyl ester resin, a bisphenol type vinyl ester resin, a novolac type vinyl ester resin, or a mixture of both can be used.
Here, the bisphenol type vinyl ester resin is an addition reaction product of a bisphenol type epoxy resin and an acid, and both have reactive unsaturated groups only at both ends.
As the bisphenol type epoxy resin, various types such as bisphenol A type, bisphenol AD type, bisphenol S type, and bisphenol F type can be used. In general, the vinyl ester resin may be one in which a styrene monomer, an acrylic monomer or the like is blended as a crosslinking agent, but the form is not particularly limited.

  As the thermosetting acrylic resin, a methyl methacrylate monomer, a polyfunctional acrylic monomer, a prepolymer, or a so-called acrylic syrup composed of a mixture of two or more kinds of polymers can be used. The form is not particularly limited.

  When using two or more types of unsaturated polyester resins, vinyl ester resins, and thermosetting acrylic resins, the optimum blending suits the desired product quality due to the characteristics of each resin and interaction with the filler. However, the blending amount is not particularly limited.

  Epoxy resins are classified into bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, cyclic aliphatic type epoxy resin, long chain aliphatic type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, etc. However, it is not particularly limited, and any of them can be used.

Epoxy resin curing agents include amino-based phthalic anhydride such as diethylenetriamine, triethylenetetramine, metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone, tetra- and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylnadic anhydride. It is classified into acid anhydrides such as pyromellitic anhydride, HET anhydride, dodecenyl succinic anhydride, and polyamides formed as a condensate of dimer acid and polyamine, but these types are not particularly limited. .
However, it is usually necessary to select and use an amino curing agent for room temperature to medium temperature curing systems, and an acid anhydride curing agent that can produce a molded product with a slow curing reaction and a small amount of curing distortion even in a high temperature system. preferable.

In the present invention, the filler may be one kind or a mixture of two or more kinds of aluminum hydroxide, silica, glass powder, and calcium carbonate, and the particle diameter of the filler may be 1 to 100 μm.
Moreover, when what used the surface of the filler which gave the silane coupling process previously is used, the adhesiveness of the filler and the resin composition can be improved, and the impact strength of a molded article can be improved.
Furthermore, in the present invention, the ratio of the filler can be 0.1 to 400 parts by weight with respect to 100 parts by weight of the thermosetting resin constituting the resin composition 7.

The resin composition 7 is blended with a curing agent. For resin systems other than the above-described epoxy resins, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexaate or t-hexylperper can be used as the curing agent. Oxy 2-ethyl hexaate or the like can be used.
For example, in the case of a vinyl ester resin, the blending ratio of the curing agent is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the resin.
In addition to the above, the resin composition 7 can also contain a pattern material, an ultraviolet absorber, a viscosity reducer, a release agent, glass fiber, a colorant, and the like.

As a viscosity reducer, for example, “W996” manufactured by BYK, for example, a trade name “Separ” manufactured by Chukyo Yushi Co., Ltd. as a mold release agent, and as a glass fiber, for example, product number “RES03X-” manufactured by Nippon Glass Co., Ltd. BM "can be used.
Moreover, as an ultraviolet absorber, a benzotriazole type, a triazine type, a benzoate type, a salicylate type, a cyanoacrylate type, an oxalic acid anilide type, a benzophenone type, etc. can be used.

In the present invention, the viscosity of the resin composition 7 is desirably 150,000 mPa · s or less.
The resin composition 7 is prepared by blending these blends at a predetermined ratio, mixing and stirring them with a stirrer or the like, and performing vacuum defoaming treatment in advance under a reduced pressure of about 20 to 50 Torr. The resin composition 7 thus vacuum degassed is released from the reduced pressure state, poured into the mold 1 having a predetermined shape, and the mold 1 is heated at a temperature of 50 to 130 ° C. for 50 to 150 minutes.
By heating, a reactive reaction between a reactive unsaturated group in the thermosetting resin in the resin composition 7 and a polymerizable monomer in the resin composition 7, or in the case of an epoxy resin, the resin composition The addition polymerization reaction between 7 and the curing agent is allowed to proceed to carry out curing molding.

From the above, according to the production method of the present invention, since the occurrence of air accumulation can be prevented, there is little performance deterioration such as an appearance defect of the bathtub B, strength reduction, etc., and there is little molding distortion and warpage. In addition to the above-described bathtub B, commercialization to a wash counter, kitchen counter, wash bowl, wall material, flooring, furniture surface material, etc. is facilitated.
(Example)

  Hereinafter, the present invention will be described in detail by way of examples. Both are examples in which a bathtub is molded with a casting mold as shown in FIG. From the following examples, it is understood that the thermosetting resin, the filler, and the like are described above, and according to the production method of the present invention, a good molded product in which the problem of air accumulation is solved can be obtained.

As a thermosetting resin, an unsaturated polyester resin (Rigolac G-400 manufactured by Showa High Polymer Co., Ltd.) was used. As a filler, aluminum hydroxide (H-made by Showa Denko Co., Ltd.) was used with respect to 100 parts by weight of the resin. 310 average particle size 20 μm) and calcium carbonate (SS- # 80 average particle size 2.6 μm) mixed at a blending ratio of 85/15 were blended in 80 parts by weight.
To this, 0.5 parts by weight of stearic acid, 2.0 parts by weight of black pattern material, 0.5 parts by weight of brown pattern material, and 1.0 part by weight of green toner are added as an internal release agent, and further cured. 2.5 parts by weight of an agent (Nippon Yushi Co., Ltd. Percure HO) was added, and this was subjected to vacuum defoaming treatment under a reduced pressure of 20 Torr for 60 minutes to obtain a resin composition for artificial marble. The viscosity of the resin composition at this time was 1260 mPa · s.
Next, a gasket is adjusted with a casting mold as shown in FIG. 1 so that the molding thickness is 10 mm, and a circular felt as a structure (needle felt GT manufactured by Nippon Felt Kogyo Co., Ltd., thickness 1.5 mm) ) Is affixed with a double-sided tape, and the blended and adjusted resin composition is injected from the inlet at an injection pressure of 1 kgf / cm ² . When the injection was completed, the injection pressure of the resin composition was increased to 3 kgf / cm ² and the installed structure (felt) was impregnated with the resin composition. Thereafter, the mold temperature was gradually raised and held at 105 ° C. for 100 minutes, and the resin composition was heated and cured to obtain a molded product of a bathtub.

As a thermosetting resin, a vinyl ester resin (Prominate P-311 manufactured by Takeda Pharmaceutical Co., Ltd.) was used, and for 100 parts by weight of this resin, aluminum hydroxide (H-320 average manufactured by Showa Denko KK) was used as a filler. 85 parts by weight of 10 μm particle size) was blended.
To this, 0.5 parts by weight of stearic acid, 1.0 part by weight of black pattern material, 1.5 parts by weight of brown pattern material, and 1.0 part by weight of blue toner are added as an internal mold release agent, and further cured. 2.5 parts by weight of an agent (Nippon Yushi Co., Ltd., Percure WO) was added, and this was vacuum defoamed under a reduced pressure of 20 Torr for 60 minutes to obtain a resin composition for artificial marble. The viscosity of the resin composition at this time was 1380 mPa · s.
Next, a gasket is adjusted so that the molding thickness becomes 10 mm with a casting mold as shown in FIG. 1, and a circular felt as a structure (Needle Felt Kogyo Co., Ltd. Needle Felt FP Thickness 2.0 mm) ) Is affixed with a double-sided tape, and the blended resin composition is injected at an injection pressure of 1.5 kgf / cm ² from the injection port. When the injection was completed, the injection pressure of the resin composition was increased to 3 kgf / cm ² and the installed structure (felt) was impregnated with the resin composition. Thereafter, the mold temperature was gradually raised and maintained at 105 ° C. for 90 minutes, and the resin composition was heat-cured to obtain a molded product of a bathtub.

As thermosetting resin, acrylic syrup resin (AC-02, manufactured by Nippon Fellow Co., Ltd.) is used, and silica (Crystalite M-3K, manufactured by Tatsumori Co., Ltd.) is used as a filler with respect to 100 parts by weight of the resin. 20 parts by weight) was blended in an amount of 70 parts by weight.
To this, 0.6 parts by weight of stearic acid, 2.0 parts by weight of black pattern material, 0.8 parts by weight of brown pattern material, and 1.2 parts by weight of pink toner are added as an internal release agent, and further cured. 1.5 parts by weight of an agent (Parkadox 16 manufactured by Kayaku Akzo Co., Ltd.) was added, and this was subjected to vacuum defoaming treatment under a reduced pressure of 20 Torr for 60 minutes to obtain a resin composition for artificial marble. The viscosity of the resin composition at this time was 1070 mPa · s.
Next, a gasket is adjusted with a casting mold as shown in FIG. 1 so that the molding thickness is 12 mm, and a circular felt as a structure (Needle Felt Industries, Ltd. Needle Felt FX, thickness 2.5 mm) ) Is affixed with a double-sided tape, and the blended and adjusted resin composition is injected at an injection pressure of 1.2 kgf / cm ² from the injection port. When the injection was completed, the injection pressure of the resin composition was increased to 3.5 kgf / cm ² and the installed structure (felt) was impregnated with the resin composition. Thereafter, the mold temperature was gradually raised and maintained at 103 ° C. for 100 minutes, and the resin composition was heat-cured to obtain a molded product of a bathtub.

As a thermosetting resin, vinyl ester resin (Lipoxy R-804 manufactured by Showa Polymer Co., Ltd.) and unsaturated polyester resin (Polymer 5250 manufactured by Takeda Pharmaceutical Co., Ltd.) are mixed at a mixing ratio of 80/20, and this mixing is performed. 95 parts by weight of aluminum hydroxide (H-320 average particle size: 10 μm, manufactured by Showa Denko KK) was added as a filler to 100 parts by weight of the resin.
As an internal mold release agent, 1.0 part by weight of stearic acid, 2.0 parts by weight of black pattern material, 0.5 part by weight of brown pattern material, 0.6 part by weight of white pattern material, 0 beige toner .8 parts by weight, and 3.0 parts by weight of a curing agent (Nippon Yushi Co., Ltd., Percure WO) were added, and this was subjected to vacuum defoaming treatment under a reduced pressure of 20 Torr for 60 minutes. A composition was obtained. The viscosity of the resin composition at this time was 1950 mPa · s.
Next, the gasket is adjusted with a casting mold as shown in FIG. 1 so that the molding thickness becomes 11 mm, and an elliptical non-woven fabric (Nippon Vilene Kogyo Co., Ltd. FRP non-woven fabric HP-21 thickness) 2.5 mm) is affixed with a double-sided tape, and the blended and adjusted resin composition is injected at an injection pressure of 1.0 kgf / cm ² from the injection port. When the injection was completed, the injection pressure of the resin composition was increased to 3.2 kgf / cm ² and the installed structure (nonwoven fabric) was impregnated with the resin composition. Thereafter, the mold temperature was gradually raised and held at 110 ° C. for 100 minutes, and the resin composition was heat-cured to obtain a molded product of a bathtub.

As a thermosetting resin, vinyl ester resin (Lipoxy R-804 manufactured by Showa Polymer Co., Ltd.) and acrylic syrup resin (XE924-1 manufactured by Mitsui Chemicals, Inc.) are mixed at a mixing ratio of 85/15, and this mixing is performed. Aluminum hydroxide (H-320 average particle size: 10 μm manufactured by Showa Denko KK) and glass powder (GF-2-30A average particle size: 30 μm manufactured by Nippon Frit Co., Ltd.) are used as fillers for 100 parts by weight of the resin. 80 parts by weight of the mixture at 80/20 was blended.
As an internal release agent, 1.0 part by weight of stearic acid, 1.5 parts by weight of a black pattern material, 0.5 part by weight of a brown pattern material, 0.8 part by weight of a white pattern material, and 0 gray toner .8 parts by weight, and further 3.5 parts by weight of a curing agent (Nippon Yushi Co., Ltd., Percure WO) were added, and this was subjected to vacuum defoaming treatment under a reduced pressure of 20 Torr for 60 minutes. A composition was obtained. The viscosity of the resin composition at this time was 930 mPa · s.
Next, the gasket is adjusted with a casting mold as shown in FIG. 1 so that the molding thickness is 10 mm, and an elliptical nonwoven fabric (Unitika Spunbond 21102BXY, thickness 1.0 mm, manufactured by Unitika Ltd.) is used as the structure. Two sheets of each of which are made to have a thickness of 2.0 mm are attached and installed with a double-sided tape, and the blended and adjusted resin composition is injected from the injection port at an injection pressure of 1.5 kgf / cm ² . When the injection was completed, the injection pressure of the resin composition was increased to 3.5 kgf / cm ² and the installed structure (nonwoven fabric) was impregnated with the resin composition. Thereafter, the mold temperature was gradually raised and held at 110 ° C. for 100 minutes, and the resin composition was heat-cured to obtain a molded product of a bathtub.

(A) thru | or (c) are sectional drawings which showed the manufacturing method of this invention. It is an enlarged view of the X section in FIG. It is a perspective view which shows an example (bathtub) of the molded article manufactured by the manufacturing method of this invention. (A) (b) is sectional drawing which showed the manufacturing method of the conventional artificial marble.

Explanation of symbols

B Bath 1 (for casting) Mold 1a Upper mold 1b Lower mold 2 Inlet 3 Air vent 3a End 4 Injection space 7 Resin composition S Structure

Claims (7)

A resin composition is prepared by blending a thermosetting resin with an additive such as a filler, an internal mold release agent, a curing agent, and a pattern material expressing an artificial marble pattern, and the resin composition is poured into a casting mold. In the method for producing artificial marble, which is produced by injecting air from the inlet to the injection space while exhausting the air accumulated in the injection space from the air vent, and heat-curing it.
In a state where the breathable structure that can prevent permeation of the resin composition is temporarily attached to the inner surface of the injection space portion so as to cover the end portion of the air extraction port on the injection space portion side, A method for producing artificial marble, characterized by injecting a resin composition. In the manufacturing method of the artificial marble of Claim 1,
The structure is in the form of a mat, cloth, sheet, mesh, etc. The thickness of the structure is ½ or less of the thickness of a molded product obtained by injecting and curing the resin composition. A method for producing artificial marble, characterized by being set to be In the manufacturing method of the artificial marble of Claim 1 or Claim 2,
In the molded product obtained by injection-curing the resin composition, the structure is integrated, and the method for producing artificial marble, In the manufacturing method of the artificial marble of Claim 3,
After the injection of the resin composition into the casting mold is completed, the structure is integrated by heating and curing the resin composition in an infiltrated and impregnated state within the thickness of the structure by increasing the injection pressure. A method for producing artificial marble, characterized in that a molded product is obtained. In the manufacturing method of the artificial marble in any one of Claims 1 thru | or 4,
The method for producing artificial marble, wherein the filler has a particle size of 1 to 100 μm. In the manufacturing method of the artificial marble in any one of Claims 1 thru | or 5,
The method for producing artificial marble, wherein the ratio of the filler is 0.1 to 400 parts by weight with respect to 100 parts by weight of the thermosetting resin constituting the resin composition. In the manufacturing method of the artificial marble in any one of Claims 1 thru | or 6,
The method for producing artificial marble, wherein the resin composition has a viscosity of 50 to 150,000 mPa · s.

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