JP2937706B2 - Method for manufacturing resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF relates to an improvement of the invention the method for producing a resin molded article.

[0002]

2. Description of the Related Art For example, in the case of a resin molded product such as a bathtub, an opaque sheet material made of an acrylic resin or an ABS resin and having a milky white color is formed into a predetermined shape by a vacuum molding method or the like. There is one in which an FRP layer is provided on the back surface of a molded product by, for example, a spray-up method and reinforced (first example).

Alternatively, a transparent gel coat layer having a thickness of about 0.3 mm is provided by spraying and curing unsaturated polyester in advance on the front mold using a front mold and a back mold, and 1-2 mm on the back mold in advance. By forming a thick FRP layer, this FRP
The layer and the gel coat layer are opposed to each other, and the surface material and the back mold material are arranged so that a predetermined gap is formed therebetween. A method for obtaining a resin molded product including a gel coat layer, an artificial marble layer, and an FRP layer is already known (second example). In this case, in the unsaturated polyester, cobalt naphthenate 0.5 to 0.5
1.0% and 1.0 to 2.0% of methyl ethyl ketone peroxide are added and mixed as a curing agent.

[0004] A transparent gel coat layer is previously formed on the front mold in the same manner as in the second example, but the FRP layer is not formed on the back mold and the front mold is formed so that a predetermined gap is formed therebetween. After placing the back mold material facing the surface and then press-filling the artificial marble material into the gap and curing it, after demolding, spray-up method, lay-up method, etc. on the side of the marble layer other than the gel coat layer side To form an FRP layer, the transparent gel coat layer, the artificial marble layer, and F
An example of obtaining a resin molded product composed of three layers of the RP layer is already known (third example).

[0005]

However, the above-mentioned first method using an opaque acrylic molded product having a predetermined shape has been proposed.
In the case of the example, there is a problem that the product has no depth. Therefore, if a transparent acrylic sheet material is used as a material, the FRP layer provided on the back surface of the acrylic molded product is seen through from the front side, and as a result, bubbles remaining due to poor defoaming in the FRP layer, FRP, There is a disadvantage that traces of the fibers constituting the layer are conspicuous.

[0006] Next, the unsaturated polyester is sprayed on the surface material to cure the resin, and a transparent gel coat layer is provided as a surface layer of the resin molded product. In the above second and third examples, the resin usually shrinks during the curing process. For this reason, it is difficult to separate the gel coat layer from the surface material. As a result,
Cracks often occur in the gel coat layer.

Further, since the unsaturated polyester is sprayed on the surface material, for example, in the case of a molded product having a large depth such as the bathtub, the resin droops on the side surface in the depth direction during the spraying operation. Etc. are likely to occur. For this reason, it is difficult to make the thickness of the gel coat layer by spraying 0.5 mm or more.

Further, when the surface layer obtained by spraying the resin is compared with the surface layer of the first example obtained by, for example, vacuum forming an acrylic sheet, the surface is not smooth, and the light transmittance and the refractive index are low. Therefore, there is a problem that the texture of the molded product is insufficient.

An object of the present invention is to provide a method for producing a resin molded product which has solved the above-mentioned problems.

[0010]

[Means for Solving the Problems]

[0011]

According to the present invention, a thermoplastic sheet material heated to a predetermined temperature is attached to a mold having a predetermined shape, and a closed space formed by the mold and the sheet material is evacuated to give the sheet material the predetermined shape. And cooling and hardening in this state to form a surface layer, removing the molded surface layer from the mold material, reattaching one of the removed sides to the auxiliary mold material, and the other side of the surface layer. Arranging a backing material of a predetermined shape at a predetermined interval to form a closed space for injecting the artificial marble material, and press-filling and hardening the artificial marble material into the closed space, and curing the artificial marble layer And a step of removing the auxiliary mold member and the back mold member from the resin molded product including the surface layer and the artificial marble layer integral with the surface layer.

The above-mentioned manufacturing method may include a step of previously providing an FRP layer on the surface of the back mold member on the closed space side. An acrylic sheet can be used as the thermoplastic sheet.

Further, according to the present invention, a thermoplastic sheet material heated to a predetermined temperature is attached to a mold having a predetermined shape, a closed space formed by the mold and the sheet material is evacuated, and the predetermined shape is formed on the sheet material. Applying and cooling and hardening in this state to form a surface layer, removing the molded surface layer from the mold material, and reattaching one of the removed sides to an auxiliary mold material; and A step of forming an artificial marble layer by spraying and curing an artificial marble material on the side, and a step of removing the auxiliary mold material from a resin molded product comprising the surface layer and the artificial marble layer integrated with the surface layer. The present invention relates to a method for manufacturing a resin molded product.

This manufacturing method may include a step of providing an FRP layer on the surface of the artificial marble layer other than the surface layer. An acrylic sheet can be used as the thermoplastic sheet.

[0016]

When the surface layer is formed, the surface layer is removed from the mold material and is supported again by the auxiliary mold material to form the artificial marble layer.
The work of removing the resin molded product from the mold becomes extremely easy,
Therefore, there is no possibility that cracks will be generated on the surface layer during the removal.

[0017]

An embodiment in which the present invention is applied to a method for manufacturing a bathtub will be described below with reference to FIG.

First, the surface layer 1 of the bathtub is formed.
The surface layer 1 is made of a transparent 6 mm thick acrylic sheet for about 1
Heat to 40 ° C., attach the periphery to the mold in an airtight state, then deaerate the closed space formed by the acrylic sheet and the mold to make the acrylic sheet conform to the mold, It is obtained by cooling and hardening after giving a predetermined shape. The mold has a predetermined concave cross-sectional shape and is provided with a small hole for exhaust at the bottom corner. Further, at the time of degassing, a plug may be used, and the acrylic sheet may be pressed auxiliary to prevent unevenness of the surface layer and obtain a sharp shape.

Next, the molded surface layer 1 is removed from the mold material, and a primer treatment is performed to adhere the artificial marble layer to the surface of the surface layer 1 which is not on the mold material side. A transparent resin may be applied to improve the quality and aesthetics of the bathtub, or both may be applied together. (Less than,
This layer is abbreviated as “intermediate layer” and is denoted by reference numeral 14)

The above-mentioned primer treatment is carried out by applying methylene dichloride as a solvent for the acrylic resin or a mixture of 30% of methyl methacrylate and 70% of unsaturated polyester. The transparent resin layer is formed by spraying an unsaturated polyester resin to a thickness of about 0.3 mm. The unsaturated polyester resin contains about 2% ultrafine anhydrous silica as a thixotropic agent. Aerosil (trade name: manufactured by Nippon Aerosil Co., Ltd.)
1.0% cobalt naphthenate, 1.0 to 1.0% as a curing agent
Add 2.0% methyl ethyl ketone peroxide,
mixing. The unsaturated polyester resin may further contain glass flakes plated with gold, silver, or the like, or aluminum foil in order to further enhance the decorativeness.

Next, an FRP layer is formed on the back mold material 3 shown in FIG. 1. In this case, 450 g / m ² of chopped strand glass mat is used as one ply, and an unsaturated polyester resin (G type) is used. Lay up by hand.
At this time, about 2% of a white pigment for blocking light rays from the back surface is usually added and mixed into the unsaturated polyester resin, but other pigments may be used for coloring. After that, a curing treatment is performed at a temperature of 50 ° C. for 2 hours to obtain an FRP layer. Instead of the lay-up method, a spray-up method may be employed.

Next, the surface layer 1 is attached to the auxiliary mold member 2, and the surface of the surface layer 1 on which the primer treatment has been performed and the FRP layer 4
The position of the back mold material 3 is determined so that the distance between the back mold material 3 and the desired thickness of the artificial marble layer is determined, and a sealing material 5 is inserted between the periphery of the surface layer 1 and the periphery of the back mold material 3. Then, the closed space 7 for injecting the artificial marble material is formed by tightening with the fastener 6. The auxiliary mold member 2 is used to prevent the surface layer 1 from being deformed due to the pressure during the injection.

Next, for the artificial marble material, a filler whose refractive index is close to that of the unsaturated polyester resin is selected to reduce irregular refraction and irregular reflection after curing so that a transparent feeling can be obtained. In this case, the resin may be mixed with a pigment in an amount of 0.01 to 0.1% so as to produce a light color tone.

Alternatively, a granulated color can be obtained by mixing a colored coarse-grained filler or pigment, but in this case,
Transparency is lost unlike the above.

The artificial marble material is first stirred using a vacuum stirrer. Next, the kneaded artificial marble material is accommodated in a tank 8 shown in FIG. 1, and the tank 8 is sealed.

Next, compressed air is supplied to the tank 8 through the air supply hole 9. As a result, the artificial marble material is pressed into the closed space 7 through the pressure hose 10 connecting the tank 8 to the closed space 7. . The air in the closed space 7 is discharged from the overflow hole 11.

Next, when the artificial marble material to be pressed reaches the overflow hole 11 as shown in FIG. 1, the air supply is stopped, the valve 12 in the pressure-resistant hose 10 is closed, and the curing process is performed at a temperature. Perform at 40 ° C. for 1 hour. Thereafter, the mold is removed, and the surface layer 1, artificial marble layer 13 and FRP layer 4 are removed.
To obtain a bathtub having three layers.

The above is a method in which an artificial marble material is pressed into the closed space 7 and filled to obtain a bathtub.
The second method of spraying the above-mentioned artificial marble material to obtain a bathtub (hereinafter abbreviated as "spraying method").
Is described below. In this method, the steps of forming the surface layer 1, attaching the surface layer 1 to the auxiliary mold material 2, such as primer treatment applied to the surface layer 1, and kneading the artificial marble material are the same as those in the casting method. Therefore, the description is omitted.

The kneaded artificial marble material is sprayed on the surface of the surface layer which has been subjected to the primer treatment and the like, and then subjected to a curing treatment at a temperature of 50 ° C. for one hour. Thus, an artificial marble layer having a thickness of about 3 mm is obtained.

Next, an FRP layer is formed on the surface of the artificial marble layer by a spray-up method or a lay-up method.
A bathtub consisting of three layers is obtained.

Example 1: Casting method

(A), formation of the intermediate layer 14

Aerosil 2.0, cobalt octenoate 0.07, and methyl ethyl ketone peroxide 1.0 were added and mixed with the bisphenol-based unsaturated polyester resin 100 as a thixotropic agent to a thickness of Spray to 0.5mm, 1.5 at 55 ℃
After curing for a long time, an intermediate layer 14 was obtained.

(B), formation of FRP layer 4

360 g / m chopped strand mat
² was defined as 1 ply, and 2 ply was applied to the portion corresponding to the bottom of the bathtub, and 1 ply was applied to the other portion using an unsaturated polyester resin (G type). In the above resin, 0.8 of methyl ethyl ketone peroxide and 0.8 of cobalt naphthenate were added to this resin 100.
5. White toner was added and mixed at a ratio of 2.0.

The curing treatment was performed at a temperature of 50 ° C. for one hour.

(C) Formation of artificial marble layer 13

As an artificial marble material, an isophthalic unsaturated polyester resin was used. In addition, this resin has a glass frit of 180, a dibutyl phthalate (DBP) of 1.0, and an accelerator NLF-10 (trade name: Kayaku Akzo Co., Ltd.)
Was added and mixed with methyl ethyl ketone peroxide at a ratio of 0.3.

The curing treatment was performed at a temperature of 55 ° C. for 1.5 hours.

(D), curing treatment after demolding

The test was performed at a temperature of 80 ° C. for 3 hours.

Example 2: Spraying method

(A) Formation of the intermediate layer 14

Aerosil 2.0, cobalt octenoate 0.07, methyl ethyl ketone peroxide 1.0 and black toner 0.1 were added to the bisphenol-based unsaturated polyester resin 100 as thixotropic agents.
The resin was mixed and sprayed so as to have a thickness of 0.5 mm, and left at room temperature for about 30 minutes to obtain a gelled intermediate layer 14 which lost fluidity.

(B) Formation of artificial marble layer 13

As an artificial marble material, an isophthalic unsaturated polyester resin was used. In this resin, 75 black colored hydrated stones, 5 white colored hydrated stones, 0.1 black toner, 0.5 cobalt naphthenate, and 0.8 methyl ethyl ketone peroxide were used. It was added and mixed in proportions.

The spray thickness was about 1 mm, and the curing treatment was performed at a temperature of 50 to 60 ° C. for 1 hour.

(C), formation of FRP layer 4

Chopped strand mat 450 g / m
² was used as one ply, and three ply layers were laminated using an unsaturated polyester resin (G type). The resin was mixed with 0.8 of methyl ethyl ketone peroxide, 0.5 of cobalt naphthenate, and 2.0 of black toner in the resin 100.

(D), curing treatment after demolding

The test was performed at a temperature of 80 ° C. for 3 hours.

Example 3: By the spraying method

(A) Formation of artificial marble layer 13

Using an isophthalic unsaturated polyester resin as an artificial marble material, this resin was directly sprayed on the surface 1 with a thickness of about 1 mm, and a curing treatment was performed at a temperature of 50 to 60 ° C. for 1 hour. . In addition, the resin 1
To 00, 75 black colored hydrated water stones, 5 white colored hydrated water stones, 0.1 black toner, 0.5 cobalt naphthenate, and 0.8 methyl ethyl ketone peroxide were added and mixed.

(B) Formation of additional layer

On the surface of the artificial marble layer on the spray side, a bisphenol-based unsaturated polyester resin having a thickness of about 0.5 m
m, and then subjected to a curing treatment at a temperature of 50 to 60 ° C. for 0.5 hour to form an additional layer, and the surface irregularities were evened out. In the above resin, Aerosil 2.0, Cobalt Octeneate 0.07, Methyl Ethyl Ketone Peroxide 1.0 and Black Toner 0.1 were added to and mixed with Resin 100.

(C), formation of FRP layer 4

[0058] Chopped strand mat 450 g / m
² was used as one ply, and three ply layers were laminated using an unsaturated polyester resin (G type). The resin was mixed with 0.8 of methyl ethyl ketone peroxide, 0.5 of cobalt naphthenate, and 2.0 of black toner in the resin 100.

(D), curing treatment after demolding

The reaction was performed at a temperature of 80 ° C. for 3 hours.

【The invention's effect】

The surface layer of the present invention formed by molding a thermoplastic sheet material gives a resin molded product a depth and a solid feeling. In particular, when the above-mentioned forming is performed by vacuum forming, a smooth surface is obtained, and the thickness of a portion to be drawn is usually 1 to 3 mm, so that tendency is increased. When an acrylic sheet is used as a thermoplastic sheet material, the above-mentioned depth and solid feeling are further improved due to its high transmittance and high refractive index.

Further, since the surface layer of the present invention is a molded article of a thermoplastic sheet material as described above, for example, a conventional surface layer obtained by spraying and curing a resin on a mold material is used.
There is no difficulty in removing the surface layer. Also, when an artificial marble layer is formed by spraying a resin, for example, on the surface layer to form an artificial marble layer, since the surface layer has already been reattached to the easy-to-removable auxiliary mold material, if the resin is cured, the resin may contract and cause shrinkage. Also, it is possible to easily remove the molded product without damaging the molded product.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an apparatus for manufacturing a resin molded product by a casting method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Surface layer 2 Auxiliary mold material 3 Back mold material 4 FRP layer 7 Closed space 13 Artificial marble layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B32B 27/04 B32B 27/04 Z 27/30 27/30 A // B29K 67:00 105: 12 105: 16 (56) Reference Document JP-A-2-160649 (JP, A) JP-A-57-87945 (JP, A) JP-A-50-87168 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 39/10-39/12 B29C 39/22-39/24 B29C 69/00-69/02 B32B 17/04 B32B 27/00-27/36

Claims (6)

(57) [Claims] 1. A thermoplastic sheet material heated to a predetermined temperature is attached to a mold having a predetermined shape, and a closed space formed by the mold and the sheet material is evacuated to give the sheet material the predetermined shape. Cooling and hardening in this state to form a surface layer, removing the molded surface layer from the mold material, reattaching one of the removed sides to the auxiliary mold material, and attaching a predetermined surface to the other side of the surface layer. Arranging a backing material of a predetermined shape at intervals and forming a closed space for injecting the artificial marble material, and press-filling and curing the artificial marble material in the closed space to form an artificial marble layer And a step of removing the auxiliary mold member and the back mold member from the resin molded product including the surface layer and the artificial marble layer integral with the surface layer. 2. The method according to claim 1, wherein the back mold material has an FR
The method of claim 1 further comprising the step of providing the P layer. 3. A process according to claim 1, wherein the use of acrylic sheet as the thermoplastic sheet material. 4. A thermoplastic sheet material heated to a predetermined temperature is attached to a mold member having a predetermined shape, and a closed space formed by the mold material and the sheet material is evacuated to impart the predetermined shape to the sheet material. Cooling and hardening in this state to form a surface layer; removing the molded surface layer from the mold material; and attaching one of the removed sides to an auxiliary mold material; and A resin molded article comprising: a step of spraying and curing an artificial marble material to form an artificial marble layer; and a step of removing the auxiliary mold member from a resin molded article comprising the surface layer and an artificial marble layer integral with the surface layer. Manufacturing method. 5. The method according to claim 4 , further comprising the step of providing an FRP layer on the surface of the artificial marble layer which is not on the side of the surface layer. 6. The method according to claim 4 , wherein an acrylic sheet is used as said thermoplastic sheet material.