JPS6159212B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a thermoplastic synthetic resin product reinforced with fillers such as glass fibers and inorganic powders, which provides high optical selectivity to the surface layer. Synthetic resin products mixed with fillers such as glass fibers and inorganic powders have properties such as high strength, heat resistance, and abrasion resistance due to the inclusion of fillers. Widely used in combination with synthetic resin materials. Particularly in the automobile industry, home appliance industry, etc., they are widely put into practical use because of their light weight and good workability, and are generally referred to as engineering plastics. However, engineering plastics include polymethyl methacrylate, epoxy, polyphenylene oxide, polycarbonate, ABS, nylon, polyarylate, polypropylene, polyoxymethylene, polybutylene terephthalate, polystyrene, unsaturated polyester, diacetate, triacetate, There are molded parts made of many individual or copolymer resins such as urea, melamine, and phenol. This has been compensated for by painting or metal plating, but this has the drawback of requiring an extremely large number of man-hours to obtain a product with good surface gloss. In addition, when a metal coating film such as plating is formed directly on the surface of a resin product containing a filler, the fibers or powder of the filler protrude from the surface during treatment with a chemical etching solution, causing unevenness on the plating surface. , the gloss becomes poor and the appearance loses its beauty. In order to repair these irregularities, it is possible to apply a thick plating film, but this would be unnecessarily labor-intensive and would not be suitable for industrial production. In view of the above facts, the present invention aims to improve the strength, rigidity, abrasion resistance, etc. of the product by forming a molded body from a thermoplastic synthetic resin mixed with fillers such as glass fiber and inorganic powder as the base of the synthetic resin product. In addition to improving various properties, a surface layer of a thermoplastic synthetic resin containing no filler is applied to part or all of the surface of the product, forming a surface with good gloss on the surface layer, and further improving the surface layer. This is a synthetic resin product that has been treated with a metal surface to form a highly luminous metal film layer, and the metal film layer may develop external defects such as blistering, peeling, and cracking even after long-term use. This is a method for manufacturing synthetic resin products that aims to provide products in extremely small quantities.The feature is that either the base material or the surface layer of the product is first molded, and then the mold surface of the mold is molded. a first step of mounting the other of the base material or the surface layer on the mold, and then melting the other of the base material or the surface layer, filling and molding the mold space of the mold, and first mounting the molded body on the mold surface of the mold. While softening or melting the surface of the molded product, a mixed layer is formed in the contact area with the molded product that is later filled and molded,
a second step of forming a mixed layer on the base material and the surface layer at the contact area thereof to form an integral bonding layer;
A third step of taking out the layered molded body of the base material and the surface layer from the mold, treating the surface of the surface layer with a chemical etching solution by a conventional method, and then applying a metal surface treatment to form a metal film layer. This relates to a method for manufacturing synthetic resin products consisting of: Furthermore, preferably in the present invention, the molded body of either the base material or the surface layer is formed using a second mold that utilizes a predetermined mold surface within the mold space of the mold and forms the molded body. The other of the base material or the surface layer is melted or filled with the first metal while the other molded body is in a melted or uncured state. Melting the synthetic resin to form the other molded body in the mold space of the product shape formed by the mold and the third mold,
The material is filled, and a mixed layer is formed at the contact area between the base material and the surface layer to integrate the base material and the surface layer. The resin used in the present invention can be any of the thermoplastic synthetic resins used in the engineering plastics mentioned above, but a preferable resin with good compatibility for integrating the two layers of the base material and the surface layer by mixed layering is polyolefin. , polyarylate,
It is a single or copolymer of polymethacrylate, polystyrene, polyvinyl halide, polyamide, polyester, polycarbonate, polyacrylonitrile, etc. As fillers, inorganic fibers such as glass fibers, asbestos, and carbon fibers, organic fibers such as vinylon fibers, and inorganic powders such as metal powders, carbon powders, and graphite powders can be used, but inorganic fibers are generally used. preferable. If the length of the filler fiber is long, the flow of the molten synthetic resin will be poor, and it will be difficult to mold it in a mold with a dense mold surface. Otherwise, it has little effect in reinforcing the product and can also make the product brittle. Although there are differences depending on the nature of the parts used in functional parts such as automobile parts, in decorative parts the fiber length is 0.4 to 4 mm, the wire diameter is 1.0 to 10 ^-4 mm,
Single fibers with a cross-sectional area of 0.8 to 8 x 10 ^-7 mm ² are preferred. The filler is kneaded with a synthetic resin in advance to form a compound or chip shape, which is then molded using an injection molding machine. The present invention will be explained based on an implementation method in which a first mold is combined with a second and third mold to perform double injection molding. FIG. 1 shows an outline of an injection molding machine used in the above method, in which a fixing plate 3 is fixed to a base 1 by an appropriate method by means of supporting rods 2, 2. and a movable plate 4 are disposed to face each other, and the movable plate 4 is reciprocated by the bearing rods 2, 2 toward the fixed plate 3 or away from the fixed plate 3. The frame 5 is rotatably supported by a support shaft 6. The movable plate 4 has two first molds 8, 8 having mold surfaces 7, 7 engraved thereon to form one side of a desired resin product.
are fixed at rotation angle positions of 180 degrees at equal distances from the center of the support shaft 6, and on the other hand, a second mold 9 and a third mold 10 are mounted on the fixed plate 3 at the same distance with respect to the center of rotation of the movable plate 4. The movable plate 4 is fixed at a rotation angle position of 180 degrees in terms of distance and at a position where it is simultaneously connected to the first molds 8, 8, respectively, when the movable plate 4 is slid forward by the support rods 2, 2. . The second mold 9 has a mold surface 11 that is to mold the surface layer of a desired product together with the mold surface 7 of the first mold 8 when the mold 9 is combined with the first mold 8. The third mold 10 has a first mold 8 when the mold 10 is combined with the first mold 8.
Along with the mold surface 7 of the mold 8, a mold surface 12 is engraved to form the shape of a desired product. The fixing plate 3 has a hole 1 opened to the mold surface 11 of the second mold 9.
3, the injection cylinder 14 is fixed to open,
First injection molding station 15 with mold 9
Further, a second injection station 1 is fixed such that an injection cylinder 17 opens in a hole 16 opening in the mold surface 12 of the third mold 10.
8. The embodiment of the present invention using the injection molding machine shown in FIG. 1 is as follows. The molds 8, 9, and 10 are sufficiently heated, the movable plate 4 is moved forward by the movable frame 5, and the second mold 9 and the third mold 10 are placed in the first molds 8 and 8, respectively. to combine. First, in the first injection station 15, a thermoplastic synthetic resin (natural material) without a filler mixed therein is press-fitted in a molten state from the injection cylinder 14 through the hole 13, and is filled into the mold space between the mold surfaces 7 and 11. A surface layer 50 of the desired product is molded. Next, the movable plate 4 is moved while the surface of the synthetic resin forming the surface layer 50 is slightly cooled and maintains its shape but is still molten inside or the surface layer 50 is unhardened and soft. When the first mold 8 with the surface layer 50 attached to the mold surface 7 is moved backward, rotated 180 degrees around the rotation center, and moved forward again, the first mold 8 with the surface layer 50 attached to the mold surface 7 is combined with the third mold 10 at the second injection station 18. be done. Mold surface 12 of third mold 10
The second injection station 18 forms a mold space with the shape of the desired product together with the mold surface 7 of the mold 8.
When a thermoplastic synthetic resin (FRTP) mixed with a filler is melted and press-fitted into the mold space through the injection cylinder 17 and the hole 16 to fill the mold space, the FRTP forms the surface layer 50 of the natural material and the third layer.
Since the surface layer 50 of the natural material is still at a high temperature, it becomes molten at the contact surface with the FRTP base material 60 that is press-fitted. Since the two are integrated, when the product is taken out after cooling in the molds 8 and 10,
The natural material surface layer 50 and the FRTP base material 60 are integrated at their contact surfaces by mixed layering to obtain a layered product. Since the surface layer 50 of this product is a natural material that does not contain fillers, it has a glossy surface that matches the surface finish of the mold surface 7, and the base material 6
0 is FRTP mixed with fillers, so it has high strength, toughness, heat resistance, and durability, and the surface layer 5
0 and the base material 60 are integrated by mixed layering,
Its adhesive strength is extremely strong. In the present invention, the surface layer 50 is formed to give gloss to the surface of the product and give it a beautiful appearance, so a thickness of about 0.2 to 1.5 mm is appropriate even for functional products such as automobile parts. In carrying out the present invention, the mold surface 7 of the first mold 8 is used as the mold surface on which the base material 60 by FRTP is to be molded, and the base material 60 is first molded at the first injection station 15, and then the second mold is molded. It is also possible to use the mold surface 12 of the injection station 18 as the mold surface on which the surface of the surface layer 50 is to be molded, and to injection mold the surface layer 50 at the second injection station 18 so as to integrate it with the base material 60. In the method using this double injection molding machine, the surface layer 5 is
0 or the base material 60 by injection molding, the movable plate 4 is retreated, rotated 180 degrees, and moved forward again, and the other injection molding is performed at the second injection station 18. Therefore, the moving time between molding at the first injection station 15 and molding at the second injection station 18 can be made extremely short.
The surface layer 5 molded by the injection station 15 of
The molded body of either 0 or the base material is subjected to injection molding at the second injection station 18 in a state in which only the surface thereof is molded and the inside is molten or in an uncured soft state to form the desired product. Therefore, it is extremely easy to mix and stratify the contact surface between the surface layer 50 and the base material 60, and the melting temperature of the synthetic resin in the second injection molding station 18 can be adjusted to the melting temperature of the synthetic resin in the first injection molding station 15. About 10-40℃ above melting temperature, preferably 20-35℃
If the temperature is high, the surface layer 5 will be removed in a normal injection molding cycle.
A product with good adhesion between the base material 60 and the base material 60 can be obtained. Further, as understood from the above-mentioned implementation method of the present invention, in the present invention, the surface layer 50 or the base material 6
It is also possible to adopt an implementation method in which either one of the two parts is molded in advance, the molded product is mounted in the mold space of an injection molding machine, and the synthetic resin to be formed with the other part is melted and injection molded. That is, if this is explained using the symbols in FIG.
Using the first mold 8 and the second mold 9, a natural material is injection molded to form a large number of surface layers 50 in advance. Next, using the first mold 8 and the third mold 10, the preformed surface layer 50 is attached to the mold surface 7 of the first mold 8, which has been preheated to a sufficiently high temperature, and the third mold The mold 10 is joined to the first mold 8, and FRTP is formed between the surface layer 50 and the mold surface 12 of the third mold 10.
When injection molding is performed by melting the FRTP to a sufficiently high temperature, the surface of the surface layer 50 attached to the mold 8 that is in contact with the molten FRTP is melted or softened at that temperature, forming a mixed layer of FRTP and natural materials. It is integrated with the base material 60 and can be layered. In this implementation method, the base material 60 is
Of course, the surface layer 50 may be formed by molding with FRTP and then molding a natural material onto one surface of the base material 60 by injection molding using an injection molding machine.
Alternatively, one of the base materials 60 preferably has a composition structure that is melted or softened at the injection temperature of the other synthetic resin to be molded later, and it is preferable that the filling pressure of the resin performed later is sufficiently high. . Another feature of the present invention is that, as described above, the surface layer 50 of a natural material with good gloss is coated on a part or all of the surface of the FRTP base material 60 with good adhesion. By applying metal surface treatment using plastic metallization on the surface of the product, the hardness, abrasion resistance, and
It is possible to improve heat resistance, give brightness and give a beautiful appearance, and the metal coating film applied by metal surface treatment can be obtained with good durability without causing cracks. be. Plastic metallizing is a method of imparting metallic properties only to the surface of synthetic resin. Usually, the surface of a synthetic resin molded product is degreased, chemically etched to form a large number of grooves on the surface, and then vacuum etched. Vapor deposition method, electroless plating, anodic sputtering,
Metal spraying, wet electroplating, and other methods are applied alone or in combination to form a metal coating layer of aluminum, tin, copper, nickel, chrome, etc., and can be applied to automobile radiator grills, headlamp housings, televisions, etc. It has been put into practical use on radio dial knobs, etc. In the present invention, the surface of a thermoplastic synthetic resin (natural material) that does not contain a filler and is layered on one side of the base material 60 of a thermoplastic synthetic resin (FRTP) reinforced with a filler is chemically etched by a conventional method. Since the metal surface treatment described above is applied after treatment (etching) with a liquid, the metal film layer formed by the treatment forms a smooth surface similar to the surface of natural materials, so FRTP is a metal that is directly applied. It has no irregularities like a film layer, and has extremely good smoothness and brightness, and has superior adhesion and durability compared to a metal film layer applied directly to a product made only of natural materials. This is the synthetic resin product according to the present invention that is FRTP.
It has a layered structure of a base material 60 and a natural material surface layer 50, and the thermal expansion coefficient of the natural material surface layer 50 is 3 to 19×10 ^-5 /°C, whereas the thermal expansion coefficient of the metal forming the metallizing film is is 0.84~1.65×
10 ^-5 /℃ (copper, nickel, chromium), and it is thought that cracks occur in the metal film layer due to the difference in coefficient of thermal expansion in the adhesive layer of only the two, but in the product according to the present invention. is base material 60
The thermal expansion coefficient of FRTP is 1.5~3.0×
10 ^-5 /℃, the surface layer of natural wood 5
It is thought that this reduces the zero linear expansion and prevents the occurrence of cracks. In addition, treatment with chemical corrosive solution (etching)
Usually contains pentane, hexane, hebutane, octane, nonane, decane, gasoline, petroleum ether,
Surface treatment of synthetic resin moldings with solvents such as petroleum benzine, ligroin, kerosene, liquid parapine, benzene, toluene, xylene, methanol, ethanol, propanol, butanol, octanol, alcohol, etc., or chemicals such as chromic acid oxidizing liquid, caustic alkal liquid, etc. The purpose is to form concave marks on the surface of the molded product and roughen it, and the plating extends into the concave marks to create an anchoring effect. Depending on the type of resin, it is Treatment (pre-etching) or sensitizing, in which divalent tin ions are adsorbed to the surface by immersing the molded body in an acidic solution of stannous chloride in hydrochloric acid, and immersion of the molded body in an acidic solution of palladium chloride in hydrochloric acid. Activation is sometimes performed to precipitate metal palladium on the surface. Example 1 A surface layer 51 of polycarbonate resin, a base body 61 of fiber-reinforced polycarbonate resin in which 30% by weight of glass fiber (commercially available product) is mixed with the polycarbonate resin are layered, and a metal film layer 70 is applied to the entire surface of the surface layer 51. molded car door handles (for the inside of the door). This handle is shown in a slope view in Figure 2, a side view in Figure 3, a top view in Figure 4, and a top view in Figure 5.
As shown in the rear view in Fig. 6 and in cross-section in Figs.
Three protruding pieces 23, 24, 25 are provided protrudingly on the lower surface of 2, and are pivoted to the door through holes 26 coaxially drilled in these protruding pieces 23, 24, 25.
A door lock device is linked to a hole 27 drilled in the free end of the door lock 4. The handle has external dimensions of 45 mm x 70 mm on the top surface, and a portion 2 mm deep from the top surface is a surface layer 51 molded from polycarbonate resin, and the rest is a base layer 51 molded from fiber-reinforced polycarbonate resin. Material 6
It is 1. In order to mold the handle, a double injection molding machine shown in FIG. 1 is used, and the first mold 8 is formed with a mold surface 7 for molding the shape of the handle above the two-dot chain line in FIG. , the second mold 9 is formed with a mold surface having a cross-sectional shape along the dashed dotted line in FIG. A surface 12 was formed. These molds 8, 9, and 10 are fixed to the movable plate 4 and the fixed plate 3, respectively, and the molds are preheated to 90°C. Between 7 and 11, polycarbonate resin was heated at a temperature of 300℃ and an injection pressure of 1200℃.
Kg/cm ² was press-fitted, and the movable frame 5 was immediately filled.
is moved backward, the movable plate 4 is rotated 180 degrees, and the movable frame 5 is advanced again, and the mold 8 is combined with the third mold 10 at the second injection station 18, and the mold surface of the mold 8 is already The fiber-reinforced polycarbonate resin is heated between the back surface of the polycarbonate resin attached to the mold surface 12 and the mold surface 12.
Press-fitted at 320℃ and injection pressure of 1300Kg/ ^cm2 .
After waiting for the resin to harden, the molded product handles were taken out from the molds 8 and 10. This molded product has a surface layer 51 of polycarbonate resin.
has an extremely smooth surface with a mirror-like luster, and approximately 70% of the surface visible when mounted on the top of the steering wheel, i.e. the inside surface of a car door, is the surface layer 5.
Although the base material 61 made of fiber-reinforced polycarbonate resin accounts for more than 90% of the weight, the surface that falls within the field of view is extremely small and does not have sufficient strength as a handle. Ta. Moreover, in a cross section taken through the handle, the surface layer 51 and the base material 61 formed a layered structure, and their joint surfaces were bonded together in a mixed layered manner. This molded handle was metallized using a plastic metallizing method in a conventional manner. That is, after the molded handle is degreased, it is pre-etched by immersing it in a dimethylformamide solution, washed with water, then etched in a mixture of chromic acid and sulfuric acid, and then immersed in an acidic solution of stannous chloride in hydrochloric acid. After activation by immersion in an acidic solution of palladium chloride in hydrochloric acid, copper plating, nickel plating and chrome plating were performed in a wet manner to form a metal film layer 70. This metal film layer 70 was formed on the entire surface of the surface layer 51 of the handle, and had a high mirror shine and an extremely good appearance. Example 2 Using the mold 8 of Example 1 and the second mold 9, the molds were preheated to 120°C and polyarylate resin (product name U polymer manufactured by Unitika) was melted to a temperature of 360°C.
The surface layer 51 was molded at an injection pressure of 1400 Kg/cm ² , and after cooling, it was taken out and kept on standby. The mold 8 and the third mold 10 of Example 1 are preheated to 120° C., the separately molded surface layer 51 is attached to a predetermined mold surface of the first mold 8, and the mold 8 and the third mold 10 are heated. A glass fiber-reinforced synthetic resin prepared by mixing 30% by weight of glass fiber (commercially available product) with the polyarylate resin is melted at 390°C between the surface layer 51 and the mold surface 12 of the mold 10. Then, the base material 61 was formed by press-filling at an injection pressure of 1600 Kg/cm ² , and at the same time, an integrated layer was formed with the surface layer 51 . The glossiness of the surface layer 51 of the molded handle and the adhesion to the base material 61 were similar to those of the molded handle of Example 1. A metal coating 70 was applied to this molded handle using the same method as in Example 1. Its appearance and shine were also similar to the molded handle of Example 1. Example 3 A film sheet of polyamide resin with a thickness of 0.4 mm was heated to 260°C using a vacuum forming machine, heated for 2 minutes, vacuum formed into the desired shape of the upper surface of the handle, cooled for 4 minutes, removed, and carried out. Surface layer 51 of example 2
It was cut to approximately the same surface area. The mold 8 of Example 1 and the third mold 10 are preheated to 70° C., the vacuum-formed surface layer is attached to a predetermined portion of the mold surface 7 of the mold 8, and the mold 8 and the third mold 10 are After bonding, between the surface layer and the mold surface 12, FRTP containing 30% by weight of glass fiber (commercially available product) mixed with the polyamide resin was melted at 300℃, and 850Kg/
The material was press-fitted with an injection pressure of cm ² to integrate the base material with the surface layer. The glossiness of the surface layer of this molded handle and the adhesion to the base material, and
When a metal film layer was applied using the same method as in Example 1, both the appearance and brightness were similar to those of the molded handle of Example 1. Comparative Example 1 The mold 8 of Example 1 and the third mold 10 were combined, preheated to 90°C, and the mold space between the mold surfaces 7 and 12 was heated.
Polycarbonate resin melted at 300℃
A handle made only of natural materials was formed by injecting and filling at an injection pressure of 1200 Kg/cm ² , and a metal film layer was formed using the same method as in Example 1. Comparative Example 2 The mold 8 of Example 1 and the third mold 10 were combined, preheated to 90°C, and the mold space between the mold surfaces 7 and 12 was filled with
FRTP is made by mixing 30% by weight of commercially available glass fiber melted at 320℃ with polycarbonate resin.
A handle made only of FRTP was formed by press-filling at a pressure of 1300 Kg/cm ² , and a metal film layer was formed using the same method as in Example 1. The test results of each molded article obtained in each of the above-mentioned Examples and Comparative Examples are shown in the following table, and various characteristics are compared and examined.

【table】

[Table] In the above table, heat cycle test is 80℃ x 60 minutes → 21℃ x 10 minutes → -30℃ x 60 minutes → 21
This test is a test in which the cycle is repeated 4 times with 10 minutes at ℃ x 10 minutes to observe the occurrence of external defects such as blisters, peeling, and cracks.
CASS test is the heat cycle test mentioned above.
CASS (American standard)
ASTM, B-368) is repeated three times to observe blistering, peeling, cracking, and the occurrence of corrosion products. This is a test in which this cycle is repeated four times, with minutes being one cycle, and the occurrence of external defects such as blistering, peeling, and cracking is observed. Also, the peeling test means that the peeling width is 10
This is a test that measures adhesion to a synthetic resin surface using an autograph at a peeling speed of 30 mm/min.
According to D-0201 Annex 1, nitrate 0.035
g, ferric chloride 0.165 g, ammonium chloride 1.0
A paste of 50 g, 50 c.c. of water, and 30 g of white china clay was applied onto a synthetic resin to a thickness of 25 to 100 μm, left to dry at room temperature for 1 hour, and then heated to 38 ± 2° C. and relative humidity of 80 to 99
This test involves leaving the paste in a humidity chamber for 16 hours, then washing it off with running water to check for corrosion. Furthermore, the heat resistance test was performed by leaving the product in an atmosphere of 80℃, 100℃, 120℃, and 140℃ for 4 hours to prevent blistering, peeling,
This is a test to observe external defects such as cracks. The bending strength was measured based on the Japanese standard JIS K-7203 "Bending test method for hard plastics" using a bending test piece treated with decorative chrome plating in a conventional manner. As is clear from the above table, the product molded by the method of the present invention has the same surface brightness as the molded product made only of natural materials in Comparative Example 1, but the product molded by the method of the present invention is equivalent to the molded product made only of natural materials shown in Comparative Example 2. The molded product was significantly inferior in brightness, and various tests showed that the molded product of Comparative Example 1, which was made only of natural materials, had cracks on the plating surface, but the product molded by the method of the present invention had no cracks on the plating surface. No damage was observed, and in terms of strength (including heat resistance tests), the product molded by the method of the present invention was significantly greater than the molded product shown in Comparative Example 1 made of natural materials only, and
It can be seen that the molded product shown in Example 2 containing only FRTP is equivalent to or better than that of the molded product shown in Example 2. As described above, when molding a product made of thermoplastic synthetic resin, the present invention maintains an appearance with the same level of gloss and brightness as a molded product made only of the resin (natural material), and also allows the resin to be made of glass. The aim is to obtain a product that has strength equal to or greater than that of a molded product made only of reinforced thermoplastic synthetic resin (FRTP) mixed with fillers such as fibers and inorganic powder.
The surface layer of the molded article made of the natural material and the
A method in which the base material of the FRTP molded product is integrally layered by mixed layering, and a metal film layer is further formed on part or all of the surface layer, and the mold surface on which the product is to be molded is formed. A first step of fitting either the base material or the surface layer into a mold having a mold space and fitting the molded object to the mold surface, and exposing at least the molded object installed in the mold into the mold space. The base material and the surface layer are molded by melting the synthetic resin that is to be molded into the other of the base material or the surface layer, and filling and molding the synthetic resin into the remaining mold space of the mold in a temperature range in which the surface to be molded softens or melts. By combining the second step of joining them together, the surface layer and the base material are formed at the desired position of the desired product by the mold surface of the mold, and the joint surface of both is formed by the molding material of the surface layer and the base material. Because they are bonded together in a mixed layer, the adhesive force is strong, and it is possible to obtain a synthetic resin product that has both the strength of the base material reinforced by the filler and the gloss and smooth brightness of the surface layer of the natural material. can. Further, according to the present invention, in the first step, a mold having a mold surface for molding the surface of either the base material or the surface layer and a second mold for molding the back surface thereof are combined. to mold the molded body,
Next, in a second step, instead of the second mold, a third mold having a mold surface for molding the remaining surface of the product is connected to the first mold, and the other of the base material or surface layer is molded. When performing filling molding of a body, the product can be molded in a short time by using a double injection molding machine, etc., and the molded body previously molded in the first mold is molded only on the surface and the inside is molded. Is it in a molten state?
Alternatively, since the molded product to be molded later is formed in a soft, uncured state as a whole, it has the advantage that a mixed layering on the joint surfaces can be formed extremely easily. Furthermore, according to the present invention, in the third step, the surface layer of the natural material of the molded product coated with the molding layer as described above is treated with a chemical etching solution in a conventional manner, and then metal surface treatment is applied to the product. A metal film layer with good smoothness can be formed on the surface, and the metal film layer is formed on the surface layer of natural materials, which have a considerable difference in coefficient of thermal expansion, but the surface layer has a value intermediate between the two in terms of coefficient of thermal expansion. Since linear expansion is suppressed in the FRTP base material, it has the advantage of being able to form a metal film layer that is less prone to cracking, blistering, and peeling. Therefore, the present invention is applicable not only to the production of automobile parts, home appliances, and other decorative parts, but also to the production of functional parts, which not only improves the appearance but also improves smoothness and strength. A metal film layer is formed on the surface layer to enhance heat resistance and corrosion resistance, as well as the durability of functional parts that require electrical properties.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view showing the main parts of a double injection molding machine suitable for carrying out the present invention, and Figs. 2 to 7 show examples of molded products manufactured according to the present invention. Fig. 2 is a slope view, Fig. 3 is a side view, Fig. 4 is a front view, Fig. 5 is a rear view, and Figs. 6 and 7 are cross-sectional views. . In the figure, 1 is the base of the injection molding machine, 2 is the support rod,
3 is a fixed plate, 4 is a movable plate, 5 is a movable frame, 6
8, 9, 10 are the support shafts, 8, 9, 10 are the molds, 7, 11, 12 are the mold surfaces, 14, 17 are the injection cylinders, 15, 18 are the injection stations, 50, 51 are the surface layers, 60, 6
1 indicates a base material, and 70 indicates a metal film layer, respectively.

Claims (1)

[Scope of Claims] 1. A thermoplastic synthetic resin molded article reinforced with a filler such as glass fiber or inorganic powder, in which part or all of one side of the base material is molded with a thermoplastic synthetic resin that does not contain the filler. In a method for manufacturing a synthetic resin product with a smooth surface layer by layering a surface layer, the molded body of either the base material or the surface layer of a mold has a mold space that forms a mold surface on which the product is to be molded. a first step of adapting and mounting the molded body to the mold surface, and molding the other of the base material or the surface layer in a temperature range in which at least the surface exposed in the mold space of the molded article mounted in the mold melts or softens. a second step of melting the synthetic resin to be molded and filling it into the remainder of the mold space of the mold, forming a mixed layer on the base material and the surface layer at the contact area thereof, and integrally applying the bonding layer; A third step consists of taking out the layered molded body of the base material and the surface layer from the mold, treating the surface of the surface layer with a chemical etching solution by a conventional method, and then applying a metal surface treatment to form a metal film layer. A method for manufacturing a synthetic resin product characterized by: 2. In the first step, a first mold having a mold surface for molding one side of the product is used, and a second mold surface having a mold surface for forming the back surface of either the base material or the surface layer of the molded product. This is carried out by joining molds and melting and filling the molded body with a synthetic resin to be molded, and the second step is performed by removing the second mold in the first step and molding the product. A third mold having a mold surface on which the other surface is to be molded is engaged with the first mold, and the other of the base material or the surface layer is melted and filled with a synthetic resin to be molded. A method for manufacturing a synthetic resin product according to claim 1, characterized in that the method is carried out by: