JPH10156854A - Manufacture of fiber reinforced rift pattern molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method capable of manufacturing a rift pattern molding having a deep beautiful rift pattern in addition to a surface which is free from any sink mark. SOLUTION: In this manufacturing method, a base material 4 which contains at least a fiber reinforced material, a scalelike decorative material, and a thermosetting resin and has a rift pattern, is pressure-molded in a mold. Then, transparent resin is fitted by forcing between the base material 4 and the mold to mold by pressurizing the base material 4 and the transparent resin. A transparent resin coated layer 5 is provided on the base material 4 thereby. The transparent resin is fitted by pressure between the base material and the molding tool at high pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fiber-reinforced grain pattern molded article, and more particularly to a method for producing a fiber-reinforced molded article having a grain pattern such as natural stone.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a fiber-reinforced grain pattern molded product having a stone pattern and reinforced with a fiber reinforced material (hereinafter sometimes referred to as a stone pattern molded product), a decorative material is used. Mixed sheet molding compound (S
MC) (Press molding (compression molding) using a mold)
There is a way to do that. The stone-pattern molded product is used as a member for a bathtub, a wall panel, a counter, or the like. The decorative material is a pulverized product such as a natural stone or a colored resin, and is a material for giving a stone pattern to a molded product. In addition, SMC is a sheet-like material obtained by impregnating a paste-like material obtained by mixing a filler, an initiator, etc. with a thermosetting resin liquid such as an unsaturated polyester resin into a fiber-reinforced material such as glass fiber. It is a molding material.

[0003]

SUMMARY OF THE INVENTION However, SMC
When a stone-patterned molded article is manufactured by a method of mixing a decorative material, sink marks (small concave portions) are easily generated on the surface of the stone-patterned molded article, and the obtained stone-patterned molded article has poor surface properties. There was a disadvantage. The sink marks are caused by a difference in polymerization shrinkage ratio and a difference in thermal expansion coefficient between materials. That is, the decorating material does not undergo polymerization shrinkage, whereas the thermosetting resin shrinks with polymerization during molding. If there is such a difference in shrinkage, the surface of the molded product is easily sinked during molding. Further, there is a difference in thermal expansion coefficient between the decoration material and the cured thermosetting resin. If there is a difference in thermal expansion coefficient, shrinkage will be non-uniform in the cooling process after release. For this reason, the surface of the molded product is liable to sink even during the cooling process.

[0004] Surface sinks on molded articles have been a particular problem in the production of stone-pattern molded articles. In order to obtain a molded product having a beautiful stone pattern, it is preferable to increase the particle size of the decorative material. However, increasing the particle size of the decorating material increases the difference in polymerization shrinkage and the difference in thermal expansion coefficient between the materials, making it difficult to prevent sink marks. Also,
According to the manufacturing method, the stone pattern is also present on the surface of the molded article. Therefore, the stone pattern has a defect that it is planar and the stone pattern has no depth.

[0005] It is an object of the present invention to provide a method capable of producing a grain pattern molded product having a deep and beautiful grain pattern in addition to a surface having no sink marks.

[0006]

According to the present invention, there is provided a method for producing a fiber-reinforced stone-pattern molded article, comprising a substrate having at least a fiber-reinforced material, a scale-like decorative material, and a thermosetting resin and having a stone-pattern. Is press-molded in a mold, and then the transparent resin is press-fitted between the substrate and the mold to press-mold the substrate and the transparent resin to form a transparent layer on the substrate. It is characterized by providing a resin coating layer.

The pressure at which the transparent resin is injected is preferably higher than the pressure of the base material immediately before the injection of the transparent resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An example of a preferable method for producing a fiber-reinforced grain pattern molded article of the present invention is a base material having at least a fiber pattern of a fiber-reinforced material, a scale-like decorative material, and a thermosetting resin. The material is pre-pressurized in a mold, and then the mold is slightly slid up to inject a transparent resin liquid between the molded substrate and the mold, clamp the mold, and This is a method in which a transparent resin coating layer is integrally formed on a base material by press-molding a material and a transparent resin, and a stone-patterned molded product is taken out of a molding die.

According to the production method of the present invention, a stone-pattern molded product 1 having a sectional structure shown in FIG. 1 is obtained. The molded article 1
Is a molded article in which a transparent resin coating layer 5 is integrally formed on a base material 4, wherein the base material 4 has a stone pattern and a fiber-reinforced material, a scale-like decoration material 3. And at least a thermosetting resin, and the transparent resin coating layer 5 is transparent.

Examples of the thermosetting resin include thermosetting resins such as unsaturated polyester resins and acrylate resins such as urethane acrylate resins. Unsaturated polyester resins are preferred as thermosetting resins because they are easily thermoset and give a stone-pattern molded article having excellent chemical resistance and durability. The thermosetting resin can be cured using an initiator (curing agent). In addition, additives such as a curing accelerator, a low-shrinkage agent, a release agent, an ultraviolet absorber, a thickener, a dye, a pigment, a filler, and a particulate decorating agent are added to the thermosetting resin as necessary. Is done.

Known unsaturated polyester resins can be used. What is an unsaturated polyester resin?
For example, a resin liquid obtained by co-condensing a polyol such as ethylene glycol, an unsaturated polycarboxylic acid such as maleic anhydride and fumaric acid, and a saturated acid such as adipic acid and orthophthalic acid with styrene, It is obtained by adding a monomer having an ethylenic double bond such as methyl methacrylate.

Known additives can be used as additives to be added to the unsaturated polyester resin and the like. As typical examples of the additive, TMPO and TMPB are used as initiators.
Cobalt naphthenate as a hardening accelerator, polystyrene, vinyl acetate resin, methacrylic resin, saturated polyester as a low-shrinkage agent, zinc stearate as an internal release agent, magnesium oxide as a thickener, filler Examples thereof include aluminum hydroxide, calcium carbonate, glass, and the like, and fine powder having a particle size of several μ to several tens μ.

The fiber reinforced material is a fibrous material for reinforcing (reinforcing) a stone-patterned molded product, and examples thereof include inorganic fibers such as glass fiber and carbon fiber, and organic fibers such as polyester fiber and aramid fiber. Fiber. When glass fiber is used as the fiber reinforced material, a stone-patterned molded product excellent in strength, chemical resistance, durability and the like can be obtained. As the glass fiber, in the case of SMC, it is preferably cut to a length of 0.5 to 1 inch. In the case of BMC (bulk molding compound), it is preferably 1/16 inch to 1 /
It is preferably cut to a length of 2 inches. The preferred content of fiber reinforced material is about 20-35% by weight, preferably 25-30% by weight for SMC, and about 1-15% by weight, preferably 5-10% by weight for BMC.

The scale-like decorative material is a flake-like material for giving a stone pattern to a molded product. The scale-like decorative material preferably has an aspect ratio (aspect ratio of the material) of 10 or more, particularly 30 to 100. When the aspect ratio is such a large value, the scale-like decorative material can be oriented parallel to the surface of the molded article, give a deep pattern to the molded article, and have excellent reinforcing properties to the molded article. Examples of the scaly decorating material include colored mica, transparent mica, colored aluminum flakes, inorganic flakes such as glass flakes, colored resin films, and cut pieces of colored fibers. Above all, mica is preferable as the flaky decorative material.

Mica (mica) has a hexagonal plate shape,
In addition, since it has pearl luster, mica is used to give a textured stone pattern to the molded article. When mica is used, a large stone pattern can be formed, the addition amount may be small, and there are advantages such as excellent adhesion with an in-mold coating agent such as an epoxy urethane type, an acrylic urethane type or a polyurethane type. As mica, muscovite and biotite can be used.

The particle size of the flake-shaped decorative material (the maximum length of the material shown in FIG. 1 as D) is 0.1 to 5.0 mm, especially 0.1 to 5.0 mm.
5 to 3 mm is preferred. The pattern provided by the flaky decorative material having such a large particle size can be observed with the naked eye, and the stone pattern is clear. Further, according to the production method of the present invention, sink does not occur in the molded product even if the particle size is large.
It is preferable that the scale-like decorative material having a particle size of 0.1 to 5.0 mm accounts for 0.3 to 20% by weight of the total amount. When the content of the flaky decorative material having a large particle size is large, a stone pattern appears effectively.

The content of the flaky decorative material is 0.3-20.
% By weight, especially 0.5 to 5% by weight. With such a content, the pattern of the molded product is beautiful.

In order to give a stone pattern to the substrate, in addition to the flaky decorative material, a granular decorative material can be further present in the substrate. An example of such a granular decorative material is a crushed product of natural stone or resin. As the granular decorative material, similarly to the scale-like decorative material, 0.1 to 5.0 mm, particularly,
Those having a particle size of 0.5 to 3 mm are preferred. Also,
It is preferable that the particulate decorative material having a particle size of 0.1 to 5.0 mm is contained in an amount of 0.5 to 20% by weight based on the total weight.

A pressure-forming material for press-forming a stone-patterned base material containing at least a fiber-reinforced material, a scale-like decoration material and a thermosetting resin is prepared, for example, as follows. Is done. That is, a paste-like mixture is obtained by mixing a fiber-reinforced material, a scale-like decoration material, and the like with a thermosetting resin liquid. Then, the mixture is impregnated and mixed with a fiber reinforced material to obtain a pressure-molded material such as SMC or BMC.

Using the above-mentioned pressure-molding material, a fiber-reinforced grain pattern molded product is molded as follows. That is, the pressure-molding material is pressure-molded in a mold to form a base material having a stone pattern, and then high pressure (for example, 200 to 300 kg) after slightly sliding up the mold or without sliding up. / Cm ² ), the transparent resin is press-fitted between the base material and the mold through an injection hole, the mold is then clamped, and the base material and the transparent resin are pressure-molded in the mold. Then, the transparent resin is cured to coat the transparent resin on the substrate, and the obtained fiber-reinforced grain pattern molded product is removed from the mold.

First, a base material is molded in a molding die, and a resin is press-fitted between the substrate and the molding die without taking out the base material from the molding die. A molding method in which a resin is coated on a substrate by successively performing pressure molding in the molding die is referred to as an in-mold coating molding method. The in-mold coating molding method is disclosed in, for example, JP-A-61-273921, and such a molding method can be applied to the present invention.

The in-mold coating molding method will be described in more detail. The pressure molding material is first pressure molded in a molding die composed of an upper mold and a lower mold to obtain a base material having a stone pattern. However, the thermosetting resin in the base material is not completely cured, but is cured to a slightly incomplete degree so that the thermosetting resin can be bonded to the transparent resin to be pressed. Next, the upper mold is slightly slid up to make it easier to inject the resin between the base material and the mold. Next, a transparent resin is injected between the substrate and the molding die through an injection hole provided in the die.
The transparent resin is injected between the substrate and the mold by a pressure higher than the pressure molding pressure of the substrate immediately before the injection of the transparent resin. High pressure is necessary to allow the transparent resin, which is an in-mold coating agent, to flow to the edge of the substrate, and to cover the entire surface of the substrate with the transparent resin.

Next, the mold is again clamped, and the base material and the transparent resin are press-molded under high pressure to harden the transparent resin, and at the same time, the transparent resin is adhered to the base material to integrate them. I do. Then, the mold is opened, and as shown in FIG. 1, the stone-pattern molded product 1 in which the cured product of the transparent resin is formed on the base material 4 as the transparent resin coating layer 5 is taken out of the molding die. The base material and the transparent resin are cured under high pressure in the molding die (between the upper die and the lower die). Therefore, even if the decorating material 3 having a large particle size is dispersedly contained in the base material 4, sink does not occur on the surface of the transparent resin coating layer 5. The thickness t of the transparent resin coating layer 5 is 0.05 to 0.5 mm, particularly 0.1 to 0.3 mm, in order to effectively prevent sink marks on the surface and to give a high quality texture to the stone pattern. Is preferred.

The transparent resin coating layer 5 must have such transparency (transparency) that the stone pattern in the substrate 4 can be seen through the naked eye. Therefore, the transparent resin coating layer 5 is formed of an additive (for example, a pigment such as calcium carbonate,
It is preferable not to include a scale decoration material). However, the additive may be contained in such a small amount that the transparency (transparency) of the transparent resin coating layer 5 is not impaired.

As a preferable transparent resin for forming the transparent resin coating layer 5, urethane acrylate resin,
An acrylate-based curable resin such as an epoxy acrylate resin is exemplified. Acrylate-based curable resins have excellent transparency and thermosetting properties, and also have excellent adhesiveness to substrates. The transparent resin is press-fitted between the substrate and the mold, and is cured and solidified under pressure and adheres to the substrate 4.

In the case of the molded product according to the production method of the present invention, the stone pattern provided by the scale decoration material 3 and the like is visually observed through the transparent resin coating layer 5. That is, the stone pattern is three-dimensional and not planar. Therefore, the stone pattern has a high quality feel.

Since the surface performance of the molded article 1 is determined by the properties of the transparent resin coating layer 5, it is also possible to use a low-grade, inexpensive material as the thermosetting resin for forming the substrate 4. . The substrate can be constituted by using SMC containing a large amount of calcium carbonate (for example, 50% by weight in SMC), and orthophthalic unsaturated polyester can be used as the unsaturated polyester resin.

As shown in FIG. 1, the scale decoration material 3 is protected by a transparent resin coating layer 5. Therefore, the molded article produced by the method of the present invention has excellent stain resistance. The molded product in which the scale decoration material is also present in the transparent resin coating layer 5 is as follows:
Since the scale decoration material is not protected by the transparent resin coating layer, the stain resistance is poor. This is because a contaminant can easily enter the interface between the scale decoration material and the cured thermosetting resin.

The molded article produced by the method of the present invention can be suitably used as a bathroom counter, a wash counter, a wall panel and the like.

[0030]

Hereinafter, the present invention will be described in detail. In the following examples,% and parts all mean% by weight and parts by weight.
The fiber-reinforced grain pattern molded product 1 shown in FIG.
Was manufactured. An SMC for press-molding the substrate 4 was produced as follows. As shown in Table 1, 35% calcium carbonate, 8% low shrinkage agent, 0.5% initiator (hardener),
1.0% thickener, 1.5% release agent, colorant (pigment)
0% and 3.0% of colored mica were mixed with 20% of an unsaturated polyester resin solution and stirred to obtain a paste-like mixture. Feeding the mixture to an SMC impregnation unit,
30 parts of glass fiber was impregnated, passed between two rolls, and a release film was stuck on both sides to obtain a sheet-like material. The sheet was left in a thermostatic chamber to thicken the unsaturated polyester resin to obtain SMC.

[0031]

[Table 1]

As the colored mica (flake shaped decorative material), white mica, black mica and red brown mica were used. In addition, 95% of the colored mica used is 0.1 to 0.1%.
It has a particle diameter D of 0.5 mm and its aspect ratio (length D
/ Average of thickness) was 30. In addition, a glass fiber cut to a length of 25 mm was used.

On the other hand, Pluglas (registered trademark) # 1000C manufactured by Dainippon Paint Co., Ltd. was prepared as a transparent resin (in-mold coating agent). The transparent resin was a urethane acrylate resin and was liquid at 25 ° C.

On the other hand, a molding die for the counter top plate is prepared, and the upper die of the molding die (a die for forming the surface of the top plate).
Was set to 140 ° C., and the temperature of the lower mold (a mold for forming the back surface of the top plate) was set to 130 ° C. Next, the SMC from which the release film has been removed is placed in the cavity between the upper mold and the lower mold set at the temperature, and after the mold clamping is completed, the SMC is applied at a pressure of 80 kg / cm ^{2 for} 6 minutes. By pressing, a stone-patterned substrate was formed. When 6 minutes have passed, the upper mold is slid up by 0.2 mm, and 200 kg of the transparent resin (Pluglas # 1000C) is weighed.
/ Cm ² between the substrate and the upper die.
The transparent resin was injected between the substrate and the upper die through an injection hole provided in the upper die. The mold was clamped again, the base material and the transparent resin were pressure-molded at a pressure of 50 kg / cm ² for 2 minutes, and the press-fitted transparent resin was cured. Then, the mold was opened and the molded product was taken out of the mold.

As shown in FIG. 1, the obtained molded article was obtained by forming a substrate 4 having a stone pattern and a transparent resin coating layer 5 as a surface layer on the substrate 4. And substrate 4
Is a layer in which colored mica 3 is dispersed in a fiber reinforced resin layer 2 made of a cured product of an unsaturated polyester resin reinforced with glass fiber, and a transparent resin coating layer 5 is formed by curing a urethane acrylate resin. It consisted of things. The pressure at which the transparent resin was injected was 200 kg / cm ² , and the pressure at which the base material was pressed immediately before the injection (80 kg / cm ^2).
cm ² ), the entire surface of the substrate 4 was covered with the transparent resin coating layer 5.

The obtained molded product had a transparent feeling and a high-quality stone pattern. The stone pattern in the substrate 4 provided by the colored mica 3 was observed through the transparent resin layer 5. There was no sink mark on the surface of the transparent resin coating layer 5, and the molded product was very excellent in surface smoothness. For this reason, the molded article could clearly show the fluorescent lamp attached to the ceiling on its surface. When the molded product was cut and the cross section was observed, the thickness of the transparent resin coating layer 5 was 0.15 to 0.15.
0.2 mm, and the thickness of the substrate (substrate) 4 was 6 mm. The mica, which is the flaky decorative material 3, is shown in FIG.
As shown in the figure, it was oriented parallel to the surface of the molded article.

[0037]

As described above, according to the manufacturing method of the present invention, sink marks do not occur on the surface of the stone pattern molded product. Therefore, the stone pattern molded article is excellent in surface properties. Further, according to the manufacturing method of the present invention, a molded article having a high-quality stone pattern can be easily manufactured. Further, it is easy to produce a stone-pattern molded product excellent in stainability and economy.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an example of a stone-pattern molded product according to the production method of the present invention.

[Explanation of symbols]

1 .... stone pattern molded product (molded product), 2 .... fiber reinforced resin layer, 3 .... flake shaped decorative material, 4 .... substrate, 5 .... transparent resin coating layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 9:00

Claims (2)

[Claims] 1. A pressure-sensitive base material containing at least a fiber-reinforced material, a scale-like decorative material, and a thermosetting resin and having a stone pattern is formed in a forming die, and then the base material and the forming die are formed. A fiber-reinforced stone pattern molded product characterized in that a transparent resin coating layer is provided on the substrate by press-fitting the transparent resin between the substrate and the base material and the transparent resin by pressure molding. Manufacturing method. 2. The method for producing a fiber-reinforced grain pattern molded product according to claim 1, wherein the pressure at which the transparent resin is injected is higher than the pressure molding pressure of the base material immediately before the injection.