JPS6144648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a thermoplastic synthetic resin product reinforced with fillers such as glass fibers and inorganic powders, which has a high gloss on its surface layer.

Synthetic resin products mixed with fillers such as glass fiber and inorganic powder have properties such as high strength, heat resistance, and abrasion resistance, and are called engineering plastics because they are lightweight and easy to process. Synthetic resins include polymethyl methacrylate, epoxy, polyphenylene oxide, polycarbonate, ABS, nylon, polyarylate, polypropylene, polyoxymethylene, polybutylene terephthalate, polystyrene, unsaturated polyester, diacetate, triacetate, Many monopolymers or copolymers such as urea, melamine, and phenol are used.

Depending on the material used, these engineering plastic molded products often have fillers exposed on the surface of the product, resulting in poor surface gloss. Attempts have been made to compensate for this by painting or metal plating, but
During pre-treatment for painting or metal plating, filler glass fibers and inorganic powders may protrude onto the product surface, requiring an extremely large number of man-hours to obtain a product with good gloss.

In view of the above facts, the present invention has been developed to improve various properties such as strength, rigidity, and abrasion resistance of a synthetic resin product by using a thermoplastic synthetic resin molded body mixed with fillers such as glass fiber and inorganic powder as a base material. At the same time, a surface layer of a thermoplastic synthetic resin not mixed with the filler is applied to part or all of the surface of the product, and the surface layer is applied to give the product surface smoothness and gloss; Furthermore, the hardness, abrasion resistance, and heat resistance of the product surface are improved by imparting arbitrary coloring to the surface layer, or by painting or plating while maintaining the smoothness, thereby imparting brightness. The characteristics of this method include dissolving the thermoplastic synthetic resin forming the surface layer in a required portion of the mold surface of a mold having a mold space in which the mold surface on which the product is to be molded is formed using a solvent. 0.01~ by spraying or brushing as a liquid
A first step of coating the substrate to a thickness of 2.0 mm and drying it to form a surface layer, and a temperature range in which the synthetic resin on the surface of the surface layer exposed in the mold space is partially melted or softened. a second step of melting the synthetic resin to be formed and filling and molding the synthetic resin together with the filler into the remainder of the mold space of the mold to form a bonding layer on the surface layer and the base material; A method for producing a synthetic resin product comprising a third step of taking out a layered molded product of a surface layer and a base material from the mold and forming a coating layer of painting or metal plating on part or all of the surface of the surface layer. be.

The product manufactured according to the present invention has a surface layer with high smoothness and gloss without mixing filler with a thickness of 0.01 to 2.0 mm on the desired surface of a base material molded from synthetic resin reinforced with filler. Since the product is layered, a surface with extremely high brightness can be formed by painting or metal plating the surface layer after molding the product.

Plastic metallizing is a known method for applying metal plating to the surface of synthetic resin products. In this method, after degreasing the surface of the product,
Pentane, hexane, hebutane, octane, nonane, decane, gasoline, petroleum ether, petroleum benzene, ligroin, kerosene, liquid paraffin,
Etching treatment is performed using a solvent such as benzene, toluene, xylene, methanol, ethanol, propanol, butanol, octanol, or alcohol, or a chemical such as a chromic acid oxidizing solution or a caustic alkaline solution to form concave marks on the surface and roughen it. Vacuum deposition method, electroless plating, anodic sputtering,
Metal spraying, wet electroplating, etc. are applied alone or in combination to form a metal coating layer of aluminum, tin, copper, nickel, chromium, etc.
Depending on the type of resin, before etching, the surface may be sensitized by immersing it in an acidic solution of stannous chloride in hydrochloric acid to adsorb divalent tin ions on the surface, or sensitizing the surface by immersing it in an acidic solution of palladium chloride in hydrochloric acid. Activation is performed to deposit metallic palladium.

The thermoplastic synthetic resin used in the present invention is
All the resins used for the engineering plastics can be used, but preferred resins with good compatibility for integrating the two layers of the surface layer and the base material by mixed lamination include polyolefin, polyacrylate,
It is a single or copolymer of polymethacrylate, polystyrene, polyvinyl halide, polyamide, polyester, polycarbonate, polyacrylonitrile, etc.

In addition, as fillers, inorganic fibers such as glass fiber, asbestos, carbon fiber, organic fibers such as vinylon fiber, and inorganic powders such as metal powder, carbon powder, graphite powder, etc. can be used, but in general, inorganic fibers are used. is preferred. If the length of the filler fiber is long, the flow of the molten synthetic resin will be poor.
Molding with a mold that has a precise surface is difficult, and if the mold is thick and short, it will have less of a reinforcing effect on the product, making it 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 and the wire diameter is 1.0 to 1 ×
A single fiber having a cross-sectional area of 10 ^-4 mm and a cross-sectional area of 0.8 to 8 x 10 ^-7 mm ² is preferable.

The filler is preferably kneaded with a synthetic resin in advance to form a compound or chip shape, and then injection molded using an injection molding machine.

Hereinafter, the present invention will be explained in detail based on examples.

FIG. 1 shows an outline of an injection molding machine used in carrying out the present invention.
A fixed plate 3 is fixed to the other end of the supporting rods 2, 2, and a movable plate 4 is opposed to the fixed plate 3.
is slidably supported by the support rods 2, 2, and is provided so as to be reciprocally movable toward the fixed plate 3 by a piston rod 6 of the cylinder device 5.

Reference numeral 7 is composed of an upper mold 8 and a lower mold 9, and a mold space 10 in which a desired product is to be molded is formed between the molds 8 and 9.
The upper mold 8 is fixed to the fixed plate 3, and the lower mold 9 is fixed to the movable plate 4 or guided (not shown) so as to be seated in a fixed position. It is detachably provided via the. When the lower mold 9 placed on the movable plate 4 is lifted up by the piston rod 6 of the cylinder device 5 and pressed against the upper mold 8, the mold surface 11 of the upper mold 8 and the lower mold 9 The mold space 10 is formed between the mold surface 12 and the mold surface 12.

An injection cylinder 14 is fixed to the fixed plate 3 so as to communicate with a hole 13 opening in the mold surface 11 of the upper mold 8. When injecting molten synthetic resin through the injection cylinder 14, cylinder 1
The resin injected from the mold 4 passes through the hole 13 of the upper mold 8 and fills the mold space 10 of the mold 7, and is molded.

Figures 2 to 7 show an automobile handle (for the inside of a door) molded according to the embodiment described below.
This is what is shown. This handle is shown in a slope view in Figure 2, a side view in Figure 3, and a top view in Figure 4.
As shown in the rear view in Fig. 5 and the cross-sectional views in Figs. 6 and 7, a handle side 21 is arranged at the front end, a mounting side 22 is arranged at the rear end, and both sides 21 and 22 are connected by connecting pieces 23 and 23. The mounting side 22 has three protruding pieces 24, 25, 25 protruding from the lower surface thereof, and a hole is coaxially formed in these three protruding pieces 24, 25. The handle is pivoted to the door through a hole 26, and is linked to a door lock device through a hole 27 formed in the free end of the central projecting piece 24, and the handle has external dimensions of 45 mm x 70 mm on the top surface. It is. As for the mold 7 in which this is to be molded, the surface shape of the upper half divided by the plane along the chain line - in FIG. Let the mold surface 11 be . According to the present invention, the portion to which the surface layer is applied is the entire surface of the mold surface 12 of the lower mold 9 of the handle or the handle side 2.
1. Portions such as the upper surface of the mounting side 22 and the connecting side 23 are included in the visual angle of the passenger when the handle is attached to the automobile door.

An embodiment of manufacturing the handle according to the invention is as follows.

1st step Prepare a solution in which a synthetic resin is dissolved in a solvent, etc., and apply this solution to the desired thickness by spraying or brushing on the entire surface or desired part of the mold surface 12 of the lower mold 9, and then is volatilized to form a surface layer 51 with a thickness of 0.01 to 2.0 mm.
The lower mold 9 is usually heated in preparation for the next step, and the surface layer 51 is dried at this preliminary temperature.

Second step: The lower mold 9 with the surface layer 51 adhered to the mold surface 12 is placed in a fixed position on the movable plate 4,
The piston rod 6 is driven by driving the cylinder device 5.
The movable plate 4 is lifted up through the lower mold 9.
is pressed onto the upper mold 8 to complete the mold space 10. Next, a synthetic resin for base material molding prepared in the form of pellets or the like by kneading the filler is put into an injection molding machine, and the mold surface 1 of the upper mold 8 and lower mold 9 is molten from the injection cylinder 14.
The remaining space in the mold space 10 between 1 and 12 is filled, and the base material 61 is molded.

The melting temperature of the synthetic resin when injected from the injection cylinder 14 is such that a part of the surface of the synthetic resin forming the surface layer 51 exposed on the mold surface 12 is melted or softened. In such a case, the synthetic resin filled into the mold space 10 through the injection cylinder 14 and the hole 13 is filled while melting a part of the exposed surface or softening the entire surface layer 51 without melting the entire surface layer 51. Since a mixed layer of the resins of both layers is formed on the joint surface of the surface layer 51 and the base material 61 and is cool-molded, the joint between the surface layer 51 and the base material 61 becomes extremely strong.

After completing the first step and the second step, the base material 61
Once solidified, the cylinder device 5 is operated to lower the piston rod 6, and the mold 7 is separated into the upper mold 8 and lower mold 9.
By dividing the molded product into two parts and taking out the molded product, a product is obtained in which a surface layer 51 with good smoothness and gloss is layered on the surface of the base material 61 on part or all of the handle surface that faces the interior of the automobile. .

Third step: Painting the entire surface or a part of the surface layer 51 of the molded handle taken out from the mold 7,
Alternatively, a film layer is formed by applying metal plating using plastic metallizing.

Example 1 A polyarylate resin (product name: U Polymer manufactured by Unitika) is dissolved in a chlorinated aliphatic hydrocarbon such as methylene chloride or chloroform to prepare a solution having the following viscosity. The viscosity of the solution is different depending on whether the solution is applied to the mold surface of the mold by spraying or by brushing.

When using the spray method, Food Cup No. 4, 20℃, 15 to 50 seconds. When using the brush coating method, Food Cup No. 4, 20℃, 30 to 150 seconds. Below the movable plate 4 of the injection molding machine. A surface layer 51 is formed by spraying or brushing the prepared synthetic resin solution on the entire mold surface 12 of the lower mold 9 removed from the mold 9 or the movable plate 4 to a thickness of 1.5 mm. .

Since the lower mold 9 is heated by the residual heat from the preceding molding after the start of production, the solvent in the solution tends to evaporate, but at the start of production the lower mold 9 is heated by the upper mold 8.
It is recommended to preheat to about 120℃. Furthermore, when applying by spraying or brushing, if a thin film is applied many times and the solvent is evaporated each time to form a thick film, there is no risk of pinholes occurring in the surface layer 51.

Next, the lower mold 9 with the surface layer 51 adhered to the mold surface 12 is fixed at a fixed position on the movable plate 4, and the lower mold 9 is brought into pressure contact with the upper mold 8 by the operation of the cylinder device 5, thereby forming the mold. A mold space 10 of No. 7 was formed, and in the remaining space of the mold space 10, a glass fiber reinforced synthetic resin obtained by mixing 30% by weight of glass fiber (commercially available product) with the polyarylate resin was melted at 390C, and 1600 kg The base material 61 was formed by press-filling from the injection cylinder 14 at an injection pressure of / ^cm2 , and was layered integrally with the surface layer 51.

As shown in FIGS. 2 to 4, this product taken out from the mold 7 has a surface layer 51 made only of polyarylate resin covering almost the entire surface that can be seen when the handle is attached to the inner surface of an automobile door. The surface is extremely smooth and has the mirror-like luster inherent to resin, and the base material 61, which accounts for most of the weight of the handle, has the strength of a glass fiber-reinforced synthetic resin. In the cross section of the handle, a thin surface layer 51 was bonded only to the surface portion of the base material 61, covering the joint surface of both as a mixed layer.

Copper plating, nickel plating and chrome plating were sequentially applied to the surface of the surface layer 51 of this handle by a conventional plastic metallizing method, resulting in a mirror-like metal covering layer with an extremely beautiful chrome luster and high brightness.

Example 2 A handle is molded using polycarbonate resin. The solvent used to prepare the solution for forming the surface layer 51 is the same as that described in Example 1.

As in Example 1, a surface layer 51 is formed on the mold surface 12 of the lower mold 9.
After the lower mold 9 is pressed against the upper mold 8, fiber-reinforced polycarbonate resin mixed with 30% by weight of glass fiber (commercially available product) is injected from the injection cylinder 14 at a temperature of 320°C and a pressure of 1300 kg/cm ^{2 .} The molded product handle was taken out from the mold 7 after waiting for the resin to harden. The glossiness and adhesion to the base material 61 of the surface layer 51 of this molded handle and the brightness of the metal coating layer formed by plastic metallization were the same as in Example 1.

Example 3 A handle is molded using polyamide resin.
A solution having the viscosity shown in Example 1 was prepared by dissolving polyamide resin in formic acid, and a surface layer 5 having a thickness of 0.4 mm was prepared.
No. 1 was applied to only the deepest bottom of the mold surface 12 of the lower mold 9 by a spraying method or a brushing method and allowed to dry.

The lower mold 9 is pressed onto the upper mold 8, and 300% of glass fiber-reinforced polyamide resin prepared by mixing 30% by weight of glass fiber (commercially available product) with the polyamide resin is added.
℃, mold space 10 at a pressure of 850Kg/ ^cm2.
It was press-fitted and filled.

The molded handle has a handle side 21 and a mounting side 2.
As shown in FIGS. 6 and 7, a surface layer 51 is layered to a predetermined width on the top of the upper surfaces of the base material 6 and the connecting piece 23, and the surface is extremely smooth and glossy.
The joint surface with No. 1 had a mixed stratification. The surface of this molded handle was cleaned and degreased, the surface layer 51 was etched, sensitized and activated, and then wet copper plating, nickel plating and chrome plating were applied. A metal film layer with a high specular chrome luster is obtained, and the remaining handle surface is a molded surface of glass fiber reinforced polyamide resin colored with pigments or dyes, resulting in a handle with a design that shows a sharp contrast between the two. Ta.

Example 4 A handle is molded using vinyl chloride resin. A vinyl chloride paste resin was prepared to the viscosity shown in Example 1, and was applied to the entire surface of the mold surface 12 of the lower mold 9 in the same manner as in Example 1 to form the surface layer, and then glass fibers were placed in the mold space 10. Glass fiber-reinforced halogenated vinyl resin mixed with 30% by weight was press-filled at a temperature of 180°C and a pressure of 1000 kg/cm ² .

Appearance of surface layer 51 of obtained handle, base material 61
When the surface layer 51 was chromed in the same manner as in Example 3, the surface layer 5
A mirror-like metal film layer with high brightness was obtained on the surface of No. 1.

Other Examples For polymethacrylate resin, a chlorinated aliphatic hydrocarbon such as methylene chloride or ethylene chloride is used as a solvent, and for polystyrene, an aromatic hydrocarbon such as acetone, benzene or toluene is used to prepare a solution having the viscosity shown in Example 1. After drying, reinforcing synthetic resin in which a filler was mixed with each resin was melted and press-filled under suitable molding conditions as shown in each of the examples above. When a metal film layer was formed in the same manner as above, results similar to those of the above-mentioned examples were obtained.

As explained in detail above, the present invention provides a substrate made of thermoplastic synthetic resin reinforced with a filler and having various properties such as sufficient strength and durability, on one side of which is made of thermoplastic synthetic resin that does not contain the filler. When manufacturing a synthetic resin product with a surface layer of resin, the liquid synthetic resin that forms the surface layer is applied by spraying, brushing, or other means to the required area of the mold surface of the mold by 0.01 to 2.0 mm. After drying, the synthetic resin to form the base material is melted at a temperature range where the synthetic resin on the surface exposed to the mold space partially melts or softens. By press-fitting the remainder of the mold space of the mold, a layered molded body is formed in which the surface layer and the base material are bonded together by mixed lamination, and the layered molded body is taken out from the metal and one part of the surface layer is formed. A method of obtaining a product having a coating or metal plating layer formed on the entire part or the whole, in which the surface layer is easily formed on the mold surface of the mold by spraying or brushing, and the synthetic resin forming the base material is formed on the surface of the mold. Since the resin is directly melted and filled into the mold in which the surface layer is formed, the manufacturing process is extremely simple, and the synthetic resin forming the base material is press-fitted into the mold due to its melting temperature. During the process, a part of the exposed surface of the surface layer is melted or softened and filled, forming a mixed layer with the surface layer and molded into one piece, so the bond between the two is strong and the surface layer is extremely thin. Since it is in the form of a film, most of the volume of the molded product is occupied by the base material, and the strength of the molded product is no different from that of a synthetic resin molded product reinforced with a filler.

Since the desired surface of the product is covered with a synthetic resin surface layer that does not contain fillers, the surface has excellent smoothness and gloss. Because it forms a film layer of extremely high brightness, it is suitable for use in automobile parts,
This invention is extremely suitable for manufacturing decorative functional parts for home appliances and the like.

In the present invention, the molding thickness of the surface layer in the first step is set to 0.01 to 2.0 mm because it is preferable to form the surface layer as thin as possible, but if the thickness is set to 0.01 mm or less, the base material is formed. This is because when the synthetic resin is melt-filled, part or all of the surface layer may melt to the surface attached to the mold and be mixed into the base material, causing the surface layer to be chipped, and when the thickness is 2.0 mm or more. This is because the number of steps involved in forming by spraying or brushing increases, and the number of steps required to form the surface layer by molding is no different from the number of steps required to form the surface layer on the mold surface of the mold.

In addition, in the present invention, the surface layer is formed into a thin film of 0.01 to 2.0 mm by spraying or brushing, and then the synthetic resin forming the base material is melt-filled and molded integrally with the surface layer. Even when a metal film layer is formed by post-plastic metallization, the coefficients of thermal expansion of the metal film layer and the base material of the filler-reinforced synthetic resin are relatively close to each other, whereas the coefficient of thermal expansion of the metal film layer interposed in the middle is relatively close to that of the base material of the filler-reinforced synthetic resin. Because the surface layer of the product is relatively thin, cracks will not occur in the metal coating layer of the product during long-term use.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an injection molding machine suitable for carrying out the present invention, Figs. 2 to 7 show examples of molded products manufactured according to the present invention, and Fig. 2 is a perspective view thereof; 3 is a side view thereof, FIG. 4 is a top view thereof, FIG. 5 is a rear view thereof, and FIGS. 6 and 7 are sectional views thereof, respectively. In the figure, 1 is the base of the injection molding machine, 2 is the support rod, 3 is the fixed plate, 4 is the movable plate, 7 is the mold, 8 is the upper mold, 9 is the lower mold, 14 is the injection cylinder,
Reference numeral 21 designates the handle side of the molded handle, 22 the mounting side thereof, 23 the connecting side thereof, 51 the surface layer thereof, and 61 the base material thereof.

Claims (1)

[Claims] 1. A surface layer molded from a thermoplastic synthetic resin that does not contain the filler is layered on one side of a base material of a thermoplastic synthetic resin molded product reinforced with a filler such as glass fiber or inorganic powder. In the method of manufacturing a synthetic resin product, a liquid of thermoplastic synthetic resin forming the surface layer is applied to a required portion of the mold surface of a mold having a mold space forming the mold surface on which the product is to be molded. The first step is to form a surface layer by applying and drying to a thickness of 0.01 to 2.0 mm by means such as spraying or brushing, and the synthetic resin on the surface of the surface layer exposed in the mold space is partially melted or Melting the thermoplastic synthetic resin to form the base material in a softening temperature range,
a second step of filling and molding the synthetic resin together with the filler into the remainder of the mold space of the mold to form a bonding layer on the surface layer and the base material by mixed lamination; A method for manufacturing a synthetic resin product, comprising a third step of taking out the layered molded product from the mold and forming a coating layer of painting or metal plating on part or all of the surface of the surface layer. 2 The third step is a step of etching a part or all of the surface of the surface layer of the layered molded product of the surface layer and base material, performing sensitization and activation, and then applying wet metal plating. A method for manufacturing a synthetic resin product according to claim 1, characterized in that: