JP2003334843A - Method for manufacturing plated injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a plated injection molding in which manufacturing steps can be simplified and which is not restricted by a product design surface. <P>SOLUTION: The method for manufacturing the plated injection molding comprises the steps of: injection filling a polymer alloy or a polymer blend in the cavity of a mold having a gradual thickness-changing part corresponding to a plating unnecessary part in the cavity so that the sectional shape of the gradual thickness-changing part satisfies formula (1) of 10≤(W/Δt)≤100 so as to flow from a part side corresponding to the plating necessary part of the cavity toward the side corresponding to a plating unnecessary part; obtaining a resin base; and then chemically plating at least the entire surface of the resin base, (wherein W is the length from the starting end to the terminal of the resin flowing direction of the injected resin of the thickness changing part of the cavity, and Δt is the thickness change of the cavity from the starting end to the terminal of the resin flowing direction of the injected resin of the thickness-changing part). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plated injection-molded product.

[0002]

2. Description of the Related Art A resin molded article has a high-class feeling by first chemically plating the surface of a resin substrate and then forming an electroplating layer on the chemical plating layer to form a metal-like surface. Although some have been made to give a solid feeling, there is a case where a plating unnecessary portion exists on a part of the surface depending on the molded product. Conventionally, in the case of producing a resin-molded product with plating in which a part requiring no plating exists in this way, first, a resist coating is applied to the part requiring no plating of a preformed resin base material, and then the surface of the resin base material is coated. A method of plating the area where the resist coating is not applied, or a method of coating the entire surface of the resin base material and then applying a decorative coating from above the plating to the areas that do not require plating to hide the plating, etc. Is being implemented.

However, each of these methods requires an additional step of applying a resist coating or a decorative coating in addition to the plating step, and is inefficient, and the plating material and the coating material are additionally required, which causes a problem in cost. is there. On the other hand, in the method described in Japanese Patent No. 2947024, a V-shaped groove is formed around the unnecessary plating portion of the resin base material, and the resin base material is first subjected to chemical plating. At this time, the bottom of the V-shaped groove is not chemically plated. Therefore, the chemical plating layer of the plating required portion and the chemical plating layer of the non-plating portion are electrically cut off at the V-shaped groove portion. Then, by energizing only the plating-required portion and electroplating only the plating-required portion, and removing the chemical plating layer of the plating-unnecessary portion, a plated molded product having a plated portion and a non-plated portion is manufactured. I am trying to do it.

However, according to this method, since the electroplating layer for covering most of the plating layer is not formed in the unnecessary plating portion, the cost of the plating material can be reduced, but a V-shaped groove is formed on the surface of the molded product which is the design surface. Since it has to be provided, there is a drawback in that the degree of freedom in product design is restricted.

[0005]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has an object to provide a method for manufacturing a plated injection-molded product which can simplify the manufacturing process and is not restricted by the design of the product. There is.

[0006]

In order to achieve the above object, a method for producing an injection-molded article with plating according to the present invention is a method for producing a resin base material having a plating-free portion adjacent to a plating-requiring portion. In a method for manufacturing an injection-molded article with plating, in which a plating layer is formed only in a required portion, a cavity has a gradually changing thickness portion corresponding to the unnecessary plating portion, and the gradually changing thickness portion has a cross-sectional shape of 10 ≦ (W / Δt) ≦ 100
The polymer alloy or the polymer blend is injected into the cavity of the mold satisfying the formula (1) so as to flow from the side of the cavity corresponding to the portion requiring plating to the side corresponding to the portion requiring no plating. After the resin base material is filled to obtain a resin base material, at least the entire surface of the resin base material is subjected to chemical plating treatment (however, the formula (1)
In the figure, W is the length of the gradually changing thickness portion of the injection resin from the start end to the end in the resin flow direction, and Δt is the thickness of the cavity of the gradually changing thickness injection resin from the start end to the end in the resin flow direction. It is a variable dimension. ).

In the present invention, the gradual thickness change portion corresponding to the unnecessary plating portion of the cavity is 10 ≦ (W / Δt) ≦ 100.
Is limited to a cross-sectional shape that satisfies the formula of 20 ≦ (W / Δ
It is preferable that t) ≦ 50 is satisfied, because the reason is that if W / Δt is larger than 100, the phase separation effect of the resin due to the change in the wall thickness becomes small and the non-adhesion effect of the chemical plating layer becomes small. , W / Δt is less than 10, there is no problem in the non-adhesion effect of the chemical plating layer, but the normal 1 mm to 3 m
In the case of an injection-molded product having a wall thickness of about m, the W dimension is shortened, so the width of the unnecessary plating portion becomes small,
This is because the effect cannot be expected sufficiently.

In the present invention, the polymer alloy or polymer blend is not particularly limited as long as it can be plated. For example, polycarbonate (hereinafter, referred to as "P
C "), polypropylene, polyacetal, polyamide, polybutylene terephthalate, acrylonitrile-styrene-butadiene copolymer (hereinafter," ABS ").
A polymer alloy or a polymer blend such as those described above), and as in claim 2, a polymer alloy or a polymer blend of an ABS resin is preferably used.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to the drawings showing the embodiments thereof. This manufacturing method includes a resin base material molding step and a plating step.

In the resin substrate molding process, the plateable polymer alloy or polymer blend will be described in detail later.
By injection filling into the cavity 3 of the mold 2 shown in FIG. 1, the resin base material 1 having the plating unnecessary portion 12 around the plating required portion 11 as shown in FIG. 1 is molded.

That is, the cavity 3 has a portion corresponding to the plating required portion 11 (hereinafter referred to as "first portion") 31.
A portion (hereinafter, referred to as a “second portion”) 32 corresponding to the plating unnecessary portion 12 is provided on the periphery of the
The cavity 33 is filled from the gate 33 provided at the center of the first portion 1, and the first portion 31 is
The second portion 32 is formed with a substantially uniform clearance throughout its thickness, and the second portion 32 has a length W from the start end to the end in the resin flow direction of the injection resin and from the start end to the end in the resin flow direction at the time of injection molding. Assuming that the thickness grading dimension is Δt (thickness t _{1 at start} end−thickness t ₂ at end), 10 ≦ (W
/ Δt) ≦ 100, the clearance is formed to satisfy the expression (1).

The cavity 3 is filled with a polymer alloy or a polymer blend, and the resin that has entered the first portion 31 from the gate 33 provided in the center of the first portion 31 has the same shape as that of the first portion 31. It spreads radially in the circumferential direction and flows toward the tip of the second portion 32.
At this time, the second portion 32 has 10 ≦ (W / Δt) ≦ 100.
Since the resin having reached the second portion 32 has a clearance satisfying the equation (1), the flow conditions such as the flow velocity, the pressure and the laminar flow state are changed, and the polymer alloy or the polymer blend is phase-separated. And degenerate. Therefore,
Due to this modification, the plating unnecessary portion 12 becomes difficult to be chemically plated.

In the plating step, the surface of the resin base material 1 thus obtained is first subjected to chemical plating. However, as described above, the unnecessary plating portion 12 is in a state where it is difficult to perform chemical plating. A chemical plating layer is formed on the surface of only the plating required portion 11. Next, the chemical plating layer formed on the plating-required portion 11 of the resin base material 1 is energized to form an electroplating layer, and an injection-molded article with plating having a plating portion and a non-plating portion is obtained. It has become.

In this manufacturing method, as described above, the wall thickness of the plating unnecessary portion 12 as the resin base material is 10 ≦ (W / Δt) ≦.
Since it is injection-molded so as to satisfy the formula of 100, a plated injection-molded article having a plated portion and a non-plated portion can be obtained without applying a resist paint or a decorative paint. Obtainable. That is, the manufacturing process can be simplified, unnecessary plating is unnecessary, the plating material can be kept to a necessary minimum, and the manufacturing cost can be reduced. Further, since it is not necessary to provide a groove or the like on the surface of the product, there is no restriction in terms of design.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the gate 33 is 1
Although it is a point, a multipoint gate may be used. Further, in the above embodiment, the plating unnecessary portion 12 is provided around the plating required portion 11 of the resin base material 1. However, one end of the resin base material 1 is a plating required portion and the other end is a plating unnecessary portion. It does not matter if it is

[0016]

EXAMPLES Specific examples of the present invention will be described in detail below in comparison with comparative examples.

Example 1 A resin base material obtained by injection-molding a PC / ABS polymer alloy in a mold 2 whose dimensions shown in FIG. 2 are as follows was subjected to chemical plating. [Dimensions of each part] L ₁ = 130 mm, L ₂ = 100 mm, L ₃ = 74 mm,
L ₄ = 45 mm, t ₁ = 2.0 mm, t ₂ = 3.0 mm,
W = 40mm, W / Δt = 40

Example 2 A resin base material obtained by injection-molding a PC / ABS polymer alloy into a mold 2 having the dimensions shown in FIG. 2 as follows was subjected to chemical plating. [Dimensions of each part] L ₁ = 130 mm, L ₂ = 100 mm, L ₃ = 74 mm,
L ₄ = 45 mm, t ₁ = 2.5 mm, t ₂ = 3.0 mm,
W = 40mm, W / Δt = 80

(Comparative Example 1) A resin base material obtained by injection-molding a PC / ABS polymer alloy into a mold 2 whose dimensions shown in FIG. 2 are as follows was subjected to chemical plating. [Dimensions of each part] L ₁ = 130 mm, L ₂ = 100 mm, L ₃ = 74 mm,
L ₄ = 45 mm, t ₁ = 2.5 mm, t ₂ = 2.8 mm,
W = 40mm, W / Δt = 133

The non-plating properties of the non-plating portions of the plated injection-molded articles obtained in Examples 1 and 2 and Comparative Example 1 were visually examined and the results are shown in Table 1. In addition, Table 1
In the table, ◯ means that the plating did not adhere to the surface, and x means that the plating adhered to the surface.

[0021]

[Table 1]

From Table 1 above, according to the manufacturing method of the present invention, the plating does not adhere to the surface of the unplated portion at the time of plating, only by controlling the thickness of the unplated portion which is the non-plated portion of the resin base material. Understand well.

[0023]

As described above, the method of manufacturing an injection-molded product with plating according to the present invention can be achieved by simply controlling the thickness of the non-plating part which is the non-plating part of the resin base material and the plating-free part at the time of plating. No plating adheres to the surface. Therefore, the manufacturing process can be simplified, the plating material can be minimized, and the manufacturing cost can be reduced. Further, there is no restriction on the design of the product, and the product can have any shape.

[Brief description of drawings]

1A and 1B show an example of a resin base material used in one embodiment of a method for producing a plated injection-molded product according to the present invention, where FIG. 1A is a plan view thereof and FIG. It is the XX sectional view taken on the line of FIG.

2 is a cross-sectional view of a mold for molding the resin base material of FIG.

[Explanation of symbols]

1 resin base material 11 Required plating area 12 No plating required 2 Resin base material 3 cavities 32 Gradual thickness change part (2nd part)

Claims (2)

[Claims] 1. A method of manufacturing a plated injection-molded article, wherein a plating layer is formed only on the plating required portion of a resin base material having a plating unnecessary portion adjacent to the plating required portion, wherein There is a corresponding gradually changing thickness portion, and the cross-sectional shape of this gradually changing thickness portion is 10 ≦ (W / Δ
t) ≦ 100 In a cavity of a mold satisfying the formula (1), a polymer alloy or a polymer blend is passed from the side of the cavity corresponding to the portion requiring plating to the side corresponding to the portion requiring no plating. A method for producing a plated injection-molded article, wherein at least the entire surface of the resin base material is subjected to chemical plating after injection-filling in a flowable manner to obtain a resin base material (however, in the formula (1), W is the length from the start end to the end of the injection resin in the resin flow direction of the gradually changing thickness portion of the cavity, and Δt is the thickness change dimension of the cavity from the start end to the end of the injection resin in the resin flow direction of the gradually changing thickness portion. It is.) 2. The method for producing a plated injection-molded article according to claim 1, wherein the polymer alloy or polymer blend is an acrylonitrile-styrene-butadiene copolymer resin.