JP7014407B2 - Plated resin molded product and its manufacturing method - Google Patents

Description

The present invention relates to a resin molded product having a plated surface (for example, a cover of a push button switch) and a method for manufacturing the same.

The molded product of the present invention can be used particularly for interior parts and exterior parts of automobiles. Examples of automobile interior parts include a push button switch cover (for example, a push button cover for a hazard lamp switch). Further, the molded product of the present invention can also be used for various molded products other than automobile parts. For example, it can be used for key tops such as keyboards of various devices such as mobile phones, personal computers, audio devices, and remote controls.

Conventionally, symbols, letters, numbers, patterns, etc. (hereinafter collectively referred to as "symbols, etc.") have been displayed on the surface of various molded products. In many cases, these symbols and the like play an important role in identifying the molded product by the user.

For example, in a push button switch, a cover is arranged on a member constituting an electrical contact to be a switch, and the switch is turned on and off by pushing the cover. On the cover, a symbol or the like indicating what kind of switch it is is displayed. One example is the cover of the push button of the hazard lamp switch as shown in FIG.

Adding a plating layer to the surface of such a molded product is also performed for the purpose of facilitating identification of symbols and the like, or for the purpose of decorating the molded product.

When the symbols and the like have island-shaped portions 2c and 2d isolated from the peripheral portion 4, such as the numbers "0" and "8" shown in FIG. 11, the island-shaped portions 2c and 2d are separated from the peripheral portion 4. There is a problem that the plating cannot be attached to the island-shaped portions 2c and 2d because the is insulated and cannot be energized.

Then, in order to energize the island-shaped portion, it is conceivable to form a notch in the symbol or the like, but if the notch is provided in the symbol or the like, as shown in FIGS. 7, 9, 12, and 14, Symbols, etc. are incomplete or inaccurate.

In order to solve this problem, for example, Japanese Patent No. 4486439 is for a push button switch having a resin with plating and a resin without plating that surrounds the surface of the resin with plating to form an island-shaped portion. The resin key top of is disclosed. As a manufacturing method thereof, a method of applying electroplating to an island-shaped portion by using a conductive portion formed in a through hole connected to the island-shaped portion from the back surface is disclosed.

Japanese Patent No. 4486439

However, the molded product described in Japanese Patent No. 4486439 has a problem that the appearance is impaired due to the presence of a large opening on the surface in order to provide a through hole. Further, if the through hole is made thin in order to avoid spoiling the appearance, it is necessary to provide a thin protruding portion having the same size as the fine through hole in the mold used for the molding. The strength of the part is low and it is extremely easy to break. Therefore, there is a problem that a mold for mass production cannot be manufactured, and as a result, mass production of molded products cannot be performed.

The present invention has been made to solve the above problems, and to provide a molded product in which island-shaped portions such as symbols are electroplated, the appearance is not impaired, and mass production is possible. , And a method of manufacturing the molded product thereof.

As a result of diligent studies, the present inventors have found a molded product and a method for producing the same, which can solve the above-mentioned problems.

Specifically, according to the present invention, for example, the following manufacturing method and molded product are provided.

(Item 1)
A method for producing a resin molded product having a surface that is at least partially plated.
The molded product has a through hole leading from the back surface of the molded product to the partially plated portion of the front surface.
The method includes a step of introducing a resin into a mold to obtain a molded product and a step of obtaining a plated layer.
Here, the step of obtaining the plating layer is an electroless plating step of forming an electroless plating layer from the back surface of the molded product to the front surface through the through hole by electroless plating, and the electroless plating layer. It includes an electroplating step of forming an electroplating layer by electroplating on the electroless plating layer using it as a current passage.
Here, the through hole has a front surface side portion and a back surface side portion, and a connection portion connecting between the front surface side portion and the back surface side portion.
Here, the width in the cross section parallel to the surface of the connection portion is large enough to form an electroless plating layer to form a current passage, and is smaller than the width that adversely affects the appearance of the molded product.
The width of the surface side portion in a cross section parallel to the surface is so large that the mold member for molding the surface side portion has the strength required for the mold member for mass production, and
The width of the back surface side portion in a cross section parallel to the front surface is so large that the mold member for molding the back surface side portion has the strength required for the mold member for mass production.
Method.
(Item 2)
The method according to item 1 above.
In the step of obtaining the molded product, a first mold having a protruding portion for forming a back surface side portion of the through hole and a second mold having a protruding portion for forming a front surface side portion of the through hole. Is used,
When the first mold and the second mold are closed, a part of the tip surface of the protruding portion of the first mold and a part of the tip surface of the protruding portion of the second mold come into contact with each other. The protruding portion of the first mold and the protruding portion of the second mold are arranged, and the tip of the protruding portion of the second mold is in contact with a part of the tip surface of the protruding portion of the first mold. A portion of the surface forms the connection.
Method.
(Item 3)
The method according to item 1 or 2 above.
The width in the cross section parallel to the surface of the connection portion is 5 μm to 0.3 mm.
The width in the cross section parallel to the front surface of the front surface side portion is 0.5 mm or more, and the width in the cross section parallel to the front surface of the back surface side portion is 0.5 mm or more.
Method.
(Item 4)
Item 6. The method according to any one of Items 1 to 3, wherein the width in a cross section parallel to the surface of the hole of the connection portion is 0.05 mm to 0.15 mm.
(Item 5)
The method according to any one of the above items 1 to 4, wherein the method is described in the above item 1.
The molded article has, on its surface, a plated first portion, an unplated second portion, and a plated third portion.
The second portion surrounds the first portion, the third portion is located outside the second portion and is not in contact with the first portion.
The through hole leads from the back surface of the molded product to the first portion.
Method.
(Item 6)
The method according to any one of the above items 1 to 5.
The process of molding the molded product
A primary molding step of introducing a first resin between a first mold for primary molding and a second mold for primary molding to form a primary resin molded product, and a first. A primary resin molded product is placed between a first mold for secondary molding and a second mold for secondary molding, and a second resin is introduced into a gap portion to form a secondary resin. Includes a secondary molding step to mold the product
The first resin is a resin that cannot be electrolessly plated, and the second resin is a resin that can be electrolessly plated.
In the electroless plating step, an electroless plating layer is formed on the second resin.
Method.
(Item 7)
Item 6. The method according to Item 6, wherein the connecting portion connecting the front surface side portion and the back surface side portion of the through hole exists at the boundary portion between the first resin and the second resin.
(Item 8)
Items 6 to 7 above, wherein the first resin is a polycarbonate resin, the second resin is an ABS resin, and the primary molding step and the secondary molding step are performed by injection molding. The method according to any one of the above.
(Item 9)
Item 6. The method according to any one of Items 1 to 8, wherein the molded product is a molded product for vehicle interior.
(Item 10)
The method according to any one of the above items 6 to 9.
The primary molding step and the secondary molding step are injection molding steps, respectively.
The first mold for the primary molding is a cavity, and the second mold for the primary molding is a core.
The first mold for the secondary molding is a cavity, and the second mold for the primary molding is used as the second mold for the secondary molding after the primary molding. Will be
Method.
(Item 11)
A resin molded product with through holes
A plating layer is formed from the back surface of the molded product to the surface of the molded product through the inner surface of the through hole.
The through hole has a front surface side portion and a back surface side portion, and a connection portion connecting between the front surface side portion and the back surface side portion.
Here, the width in the cross section parallel to the surface of the connection portion is large enough to form an electroless plating layer to form a current passage, and is smaller than the width that adversely affects the appearance of the molded product.
The width of the surface side portion in a cross section parallel to the surface is so large that the mold member for molding the surface side portion has the strength required for the mold member for mass production, and
The width of the back surface side portion in a cross section parallel to the front surface is so large that the mold member for molding the back surface side portion has the strength required for the mold member for mass production.
Resin molded product.
(Item 12)
Item 2. The resin molded product according to Item 11 above.
The width in the cross section parallel to the surface of the connection portion is 5 μm to 0.3 mm.
The width in the cross section parallel to the front surface of the front surface side portion is 0.5 mm or more, and the width in the cross section parallel to the front surface of the back surface side portion is 0.5 mm or more.
Resin molded product.
(Item 13)
Item 12. The resin molded product according to Item 11 or 12, wherein the width in the cross section parallel to the surface of the hole of the connection portion is 0.05 mm to 0.15 mm.
(Item 14)
Item 2. Resin molded product.
(Item 15)
Item 12. The resin molded product according to Item 14, wherein the island-shaped portion is formed of ABS resin and the surrounding portion is formed of polycarbonate resin.
(Item 16)
Item 14 or 15 above, wherein the through hole exists at a boundary portion between the island-shaped portion and the surrounding portion, and the height of the surface of the surrounding portion is the same as the height of the connecting portion of the through hole. The resin molded product described in.

According to the present invention, there is provided a molded product in which island-shaped portions such as symbols are electroplated, the appearance is not impaired, and the molded product can be mass-produced. For example, as shown in FIGS. 5, 6, 10 and 13, according to the present invention, there is provided a molded product whose appearance is not significantly impaired. The present invention also provides a manufacturing method capable of mass-producing such molded articles.

According to the present invention, an electroless plating layer is formed from the back surface to the surface of the island-shaped portion through a through hole, and the electroless plating layer is used as a current passage for an electroplating process to form an island shape. It is possible to form an electroplating layer on the portion. Further, since the through holes are inconspicuous, the appearance of the surface of the molded product is not impaired. In addition, since it is not necessary to provide the mold with a thin protruding portion that is easily damaged, mass production of molded products is possible.

FIG. 1 is a cross-sectional view of an example of a molded product of the present invention. FIG. 2 is a plan view of one example of the molded product of the present invention. FIG. 3 is a partially enlarged view of the periphery of the through hole of FIG. FIG. 4 is a partially enlarged view of a mold and a through hole of the molded product when molding the molded product of FIG. 1. FIG. 5 is a plan view of one example of the molded product of the present invention. FIG. 6 is a plan view of one example of the molded product of the present invention. FIG. 7 is a plan view of an example of a molded product of the prior art. FIG. 8 is a plan view of one example of an unplated push button cover for a hazard lamp switch. FIG. 9 is a plan view of one example of a push button cover for a hazard lamp switch in which a notch is provided in a triangular symbol. FIG. 10 is a plan view of one example of the molded product of the present invention. FIG. 11 is a plan view of one example of a molded product on which numbers are displayed. FIG. 12 is a plan view of an example in which the numbers of the molded product of FIG. 11 are notched. FIG. 13 is a photograph of one example of a push button cover for a hazard lamp switch manufactured by the method of the present invention. FIG. 14 is a photograph of one example of a push button cover for a hazard lamp switch in which a notch is provided in a triangular symbol.

Hereinafter, the present invention will be described in detail.

(Molding)
The present invention relates to, in one embodiment, a molded product containing a plating layer including a molded product made of resin and a plating layer formed on the surface of the molded product.

In the present specification, the molded product means a product obtained by molding a resin. The molded product includes both an intermediate product after molding and before coating the plating layer, and a final product after coating the plating layer.

(resin)
In the molded product of the present invention, a resin capable of electroless plating is used. In the present specification, a resin capable of electroless plating is also referred to as a resin capable of electroless plating.

As the resin capable of electroless plating, an etching solution for performing electroless plating and a resin whose surface is etched by an etching method can be used. The resin that can be electroless plated may be a synthetic resin or a natural resin. A synthetic resin containing a butadiene component is preferable. In the present specification, the butadiene component refers to a polymer molecule obtained by polymerizing butadiene or a copolymer molecule obtained by polymerizing a monomer mixture containing butadiene.

Specific examples of the resin that can be electrolessly plated include acrylonitrile-butadiene-styrene copolymer (ABS resin) and an alloy resin of ABS resin and other resins, for example, an alloy resin of ABS resin and polycarbonate (PC) resin. Can be mentioned. If necessary, these resins may be appropriately modified before use. ABS resin is most preferred.

In one preferred embodiment, a resin that cannot be electroless plated can be used in the molded product of the present invention in addition to the resin that can be electroless plated. As the resin that cannot be electroless plated, a resin whose surface is not etched by an etching solution and an etching method for performing electroless plating can be used. The resin that cannot be electroless plated may be a synthetic resin or a natural resin. Further, it may be a thermoplastic resin or a thermosetting resin. Thermoplastic resin is preferred. Examples of the thermoplastic resin include, for example, polycarbonate resin, polyethylene resin, AS resin, acrylic resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polymethyl methacrylate resin, polyallyl diglycol carbonate resin, polypropylene resin, polyphenylene oxide resin, and the like. Examples thereof include polyacetal resin, polyamide resin, and polysulphon resin. One preferred embodiment includes polycarbonate resin.

The above-mentioned polycarbonate resin or the like is a resin that cannot be electrolessly plated, but by alloying or modifying these resins, it may become a resin that can be electrolessly plated. The resin thus obtained can be used as a resin capable of electroless plating in the present invention.

It should be noted that the etching solution and etching method generally used at present for electroless plating cannot substantially etch a resin containing no butadiene component. When using such commonly used etching solutions and etching methods, the resin that can be electroless plated is a resin that contains a butadiene component, and the resin that cannot be electroless plated is a resin that does not contain a butadiene component. ..

However, even with a resin that does not contain a butadiene component (for example, the resin exemplified in the description of the resin that cannot be electroless plated), the surface of the resin is etched depending on the type of etching solution and the etching method for performing electroless plating. In some cases, electroless plating becomes possible. Alternatively, by using a surface treatment method other than the etching method, the surface of the resin may be surface-treated to enable electroless plating. When such an etching solution and an etching method or a surface treatment method are used, the etched resin or the surface-treated resin corresponds to a resin capable of electroless plating.

The molded product of the present invention may be a molded product molded from one type of resin material, or may be a molded product molded from two or more different resin materials by two-color molding or the like. .. For example, when the molded product is made of two or more different resin materials, it may be made of a resin that can be electrolessly plated and a resin that cannot be electrolessly plated. The molded product may also be made of a transparent resin material and an opaque resin material, or may be made of a transparent resin material and a colored resin material.

In the present specification, the resin material means a molding material containing a resin. The resin material may contain, if necessary, an additive for molding, an additive according to the required performance of the final product, and the like, in addition to the resin. Specific examples of the additives used include colorants, plasticizers, mold release agents, flame retardants and the like.

When the molded product is made of two or more different resin materials, the two or more different resin materials may have different resins, the same resin, and only different additive formulations. May be good.

(Plating material)
In the molded product of the present invention, at least a part of the surface thereof is covered with a plating layer.

In the present specification, the plating material refers to a material used for plating on a resin. The plating material is generally an electroless plating material and an electroplating material, and an electroless plating layer and a plating layer can be formed on the surface of a molded product by a conventionally known method.

In the present specification, the electroless plating material refers to a material used for electroless plating on a resin. Electroless plating is formed on the surface by bringing the electroless plating material into contact with the surface of the molded product and precipitating metal on the surface. And it becomes possible to perform electroplating on it.

In the molded product of the present invention, a plating layer known as a plating layer for coating the resin is laminated. The plating layer may be formed by a conventionally known method.

For example, copper-nickel-chrome plating can be used. For example, a three-layer plating layer having a copper plating layer as a base plating layer, a nickel plating layer as an intermediate plating layer, and a chrome plating layer or a chrome alloy layer as an outer plating layer can be used.

The film thickness of each plating layer can be arbitrarily set according to the intended use of the molded product and the like.

For example, the film thickness of the base plating layer is preferably 10 μm or more, more preferably 20 μm or more. Further, it is preferably 50 μm or less, more preferably 30 μm or less. If it is too thin or too thick, sufficient performance as plating may not be obtained.

The film thickness of the intermediate plating layer is preferably 3 μm or more, more preferably 5 μm or more. It is preferably 30 μm or less, more preferably 15 μm or less. If it is too thin or too thick, sufficient performance as plating may not be obtained.

The film thickness of the outer plating layer is preferably 0.05 μm or more, more preferably 0.2 μm or more. When the outer plating layer is formed of trivalent chromium, the film thickness is preferably 0.1 μm or more. When formed of hexavalent chromium, the film thickness is preferably 0.1 μm or more, and a particularly preferable film thickness is 0.2 μm or more. The film thickness of the outer plating layer is preferably 0.8 μm or less, more preferably 0.4 μm or less. If it is too thin or too thick, sufficient performance as plating may not be obtained.

(Symbols, etc.)
In the molded product of the present invention, symbols, letters, numbers, patterns and the like are displayed on the surface. Examples of symbols include triangles, rectangles, circles, and the like. As a specific example, for example, the molded product of the present invention can be used as a push button switch for lighting a hazard lamp on which a triangular mark is displayed.

(Other parts)
Other members can be attached to the molded product of the present invention, if necessary. In one embodiment, a lighting member such as an LED may be arranged inside or inside the molded product of the present invention. In this case, light can be transmitted through the transparent member and the plating layer.

(Use of molded products)
Specific applications of the molded product of the present invention include, for example, a cover portion of a push button switch. In one embodiment, the molded article of the present invention is a part of an automobile interior material. For example, it can be suitably used as a cover for a push button for a hazard lamp switch.

(Embodiment of molded product)
Hereinafter, the molded article of the present invention in a preferred embodiment will be described with reference to the drawings. In the molded product of the present invention, the width of the connecting portion of the through hole is very narrow, so that the lines overlap when drawn with the actual dimensions. Therefore, it is difficult to accurately draw the connection portion of the through hole, and if the connection portion of the through hole is accurately drawn, the invention may be difficult to understand. Therefore, in the drawings, each dimension of the molded product and the ratio of the dimensions (for example, the ratio of the length to the width) may differ from the actual product. That is, the dimensions and the ratio of dimensions of the molded article or the like of the present invention are not limited to those described in the drawings, and should be interpreted in consideration of the description in the specification. Further, in the drawings, members around the product such as runners are omitted.

Referring to FIGS. 1, 2 and 5, the molded product 1 has an island-shaped portion 2 in the center, and the surrounding portion 3 surrounds the island-shaped portion 2. Further, a peripheral portion 4 exists around the surrounding portion 3. The island-shaped portion 2 is provided with a through hole 5.

The island-shaped portion 2 is formed of a resin capable of electroless plating, an electroless plating layer is laminated on the resin, and an electroplating layer is formed on the electroless plating layer. In a preferred embodiment, a copper layer, a nickel layer, and a chromium layer are laminated in order from the bottom on the electroless plating layer as an electroplating layer.

A through hole 5 is provided in the island-shaped portion. In a preferred embodiment, a through hole 5 is provided at the boundary portion between the island-shaped portion 2 and the surrounding portion 3, and the height of the surface of the surrounding portion is slightly lower than the surface of the island-shaped portion. In one embodiment, it is about 0.01 mm to about 1 mm lower.

The surrounding portion 3 is made of a resin that cannot be electrolessly plated. Therefore, even in the final product, the surrounding portion 3 is not plated and has a color tone different from that of the island-shaped portion 2.

The peripheral portion 4 is formed of a resin that can be electrolessly plated. A plating layer is formed on the resin. In a preferred embodiment, the copper layer, the nickel layer, and the chromium layer are laminated in this order from the bottom.

Referring to FIG. 3 which is an enlarged view of the vicinity of the through hole in FIG. 1, the front surface side portion 5a of the through hole is a hole having a large width, and the back surface side portion 5c is also a hole having a large width. Since the width of the connecting portion 5b connecting the front surface side portion 5a and the back surface side portion 5c is very narrow, the through hole is inconspicuous and almost invisible when the molded product is viewed from above with the naked eye.

As described above, in the present invention, the width of the connecting portion 5b connecting between the front surface side portion 5a and the back surface side portion 5c of the through hole is very narrow, whereby the through hole is formed in the product. The shape is inconspicuous.

The surface side portion of the through hole is designed to a large value so that the mold member for molding the surface side portion can have the strength required for the mold member for mass production. Therefore, the surface side portion of the through hole preferably has a width of 0.5 mm or more, more preferably 1 mm or more, further preferably 2 mm or more, and further preferably 3 mm or more. Is particularly preferred. Further, it is preferable to have a width of 10 mm or less, and more preferably to have a width of 5 mm or less.

The width of the back surface side portion of the through hole is designed to a large value so that the mold member for molding the back surface side portion can have the strength required for the mold member for mass production. Therefore, the back surface side portion of the through hole preferably has a width of 0.5 mm or more, more preferably 1 mm or more, further preferably 2 mm or more, and further preferably 3 mm or more. Is particularly preferred. Further, it is preferable to have a width of 10 mm or less, and more preferably to have a width of 5 mm or less.

The width of the connection portion connecting the front surface side portion and the back surface side portion of the through hole is large enough to allow the electroless plating material to flow and form a current passage for electroplating, and the molded product. Designed to be smaller than the width that adversely affects the appearance of the. In one embodiment, the width of the connecting portion of the through hole is 5 μm (0.005 mm) or more, preferably 0.01 mm or more, more preferably 0.02 mm or more, still more preferably. It is 0.05 mm or more, and particularly preferably 0.1 mm or more. In one embodiment, it can be 0.8 mm or more. If it is too narrow, it may be difficult to form a current passage for the electroless plating layer at the connection portion. The width of the connection portion of the through hole is preferably 3 mm or less, more preferably 1.5 mm or less, still more preferably 0.5 mm or less, and particularly preferably 0.2 mm. It is as follows. If it is too wide, the through holes will be easily visible when the surface of the molded product is viewed from above, and the appearance will be easily spoiled.

In the present specification, the width of the through hole means the width of the flow path when the plating material flows through the through hole. That is, the width of the through hole means the distance between two opposing points on the outer circumference of the cross-sectional shape assuming a cross section parallel to the surface of the molded product in the through hole. For example, if the cross-sectional shape is a circle, its diameter is the width. If the cross-sectional shape is elliptical, its minor axis is the width. When the cross-sectional shape is an elongated shape and two opposing lines define the longitudinal direction of the shape, the distance between the two lines is the width. For example, if the cross-sectional shape is rectangular, the length of the short side is the width. For example, in the case of the through hole shown in FIGS. 1 to 4, it means the horizontal distance thereof.

The cross-sectional shape of the connecting portion of the through hole is not particularly limited. For example, it may have a circular or elliptical shape, or it may have an elongated shape such as a rectangle.

The position where the through hole is provided is not particularly limited as long as it is a position where a current passage to the island-shaped portion 2 can be formed. A through hole may be provided inside the island-shaped portion 2, or a through hole may be provided on the outer peripheral portion of the island-shaped portion 2. As shown in FIGS. 1 to 3, it is preferable that the position is in contact with the outer periphery of the island-shaped portion 2. That is, it is preferable to provide a through hole at the boundary portion between the island-shaped portion and the surrounding portion.

In one embodiment, the shape of the connecting portion of the through hole is an elongated shape in contact with the outer periphery of the island-shaped portion. The line constituting a part of the outer circumference is used as the first line for defining the outer shape of the cross section of the connecting portion of the through hole, and the same line is arranged at a position separated by a distance corresponding to the desired width to define the outer shape. It is preferable that the second line is used and the portion surrounded by the first line and the second line is a through hole. For example, if the outer shape of the island-shaped portion has a straight line portion, it is preferable to form a rectangular through hole surrounded by a straight line portion parallel to the straight line portion. For example, if the outer shape of the island-shaped portion is circular, it is preferable to form a through hole having a shape surrounded by a part of the circumference of the circle of the outer contour and a part of the circumference of the concentric circle slightly outside the circle. If the connecting portion of the through hole has an elongated shape in contact with the outer periphery of the island-shaped portion, the through hole becomes more inconspicuous and it becomes easy to secure a sufficient current passage for electroplating.

The length of the cross section of the connecting portion of the through hole is not particularly limited, and can be appropriately set according to the shape and dimensions of the island-shaped portion. 0.1 mm or more is preferable, 0.3 mm or more is more preferable, 0.5 mm or more is further preferable, and 1 mm or more is particularly preferable. If it is too short, it may be difficult for electroless plating to form a passage of sufficient current for electroplating. Further, the upper limit of the length of the cross section can be set to the maximum dimension of the island-shaped portion.

In the molded product of the present invention, since the surface side portion 5a of the through hole is present, the location of the surface side portion 5a is recessed.

The depth of the surface side portion 5a, that is, the depth of the recess from the surface of the molded product is not particularly limited. For example, it can be 0.1 mm or more, 0.2 mm or more, or 0.3 mm or more. Further, for example, it can be 2 mm or less, 1 mm or less, or 0.5 mm or less.

In the molded product of the present invention, since the surface side portion 5a of the through hole is present, the location of the surface side portion 5a is recessed. If a through hole is provided at the boundary between the island-shaped portion and the surrounding portion, the recessed portion can be formed on the outside of the island-shaped portion, and the entire island-shaped portion can be made flat.

The island portion may further have a second unplated portion inside thereof, if desired. Further, an additional island-shaped portion may be provided inside the second unplated portion. For example, as shown in FIG. 6, the molded product 12 has a first surrounding portion 31 inside the peripheral portion 4 and a first island-shaped portion 21 surrounded by the first surrounding portion 31. However, the second island-shaped portion 32 may be provided inside the first island-shaped portion 21, and the second island-shaped portion 22 surrounded by the second surrounding portion 32 may be provided.

(exterior)
In the molded product of the present invention, the appearance of the surface is not impaired by the notch. For example, as can be understood from FIGS. 1 to 3, 5, 6, 10 and 13, in the molded product of the present invention, the appearance of symbols and the like to be attached to the surface is not substantially impaired. Is provided.

(Production method)
The production method of the present invention produces a resin molded product having a surface that is at least partially plated.

In the manufacturing method of the present invention, the molded product of the present invention is manufactured. As described above, the molded article of the present invention has a through hole leading from the back surface of the molded article to the partially plated portion of the front surface. The through hole has a front surface side portion having a thick width, a back surface side portion having a thick width, and a narrow connection portion connecting between the front surface side portion and the back surface side portion.

(Mold)
In the manufacturing process of the present invention, at least one pair of molds (eg, cavities and cores) is used. Specifically, a mold having a shape corresponding to the shape of the molded product described above is used. Preferably, two pairs of molds (eg, a cavity for primary molding and a cavity for secondary molding and two cores for primary molding and secondary molding) are used.

A preferred embodiment will be described with reference to FIGS. 3 and 4, wherein the first mold 6 (preferably the cavity) of the pair of molds has a protruding portion 6a for forming a surface side portion of the through hole. prepare. Here, the protruding portion has a thickness that can secure sufficient strength. Further, the second mold 7 (preferably the core) of the pair of molds is provided with a protruding portion 7a for forming the back side portion of the through hole. Here, the protruding portion 6a from the first mold 6 and the protruding portion 7a from the second mold 7 are arranged at slightly offset positions. That is, the position of the center of the protruding portion 6a and the position of the center of the protruding portion 7a from the second mold 7 are not the same, but are slightly offset, and are connected by the combination of the protruding portion 6a and the protruding portion 7a. A through hole having a portion is formed. Here, the protruding portion 6a and the protruding portion 7a each have a thickness capable of ensuring sufficient strength. Then, the mold is closed, the tip surface 6b of the protruding portion of the first mold 6 and the tip surface 7b of the protruding portion of the second mold are brought into contact with each other with a narrow width to introduce the resin, and the first mold 6 is introduced. The protruding portion 6a of the above forms the surface side portion 5a of the through hole 5. The protruding portion 7a of the second mold 7 forms the back surface side portion 5c of the through hole 5. Then, the connecting portion 5b of the through hole is formed by the narrow portion where the tip surface 6b of the protruding portion of the first mold and the tip surface 7b of the protruding portion of the second mold are in contact with each other. That is, in the molded product of the present invention, in the connecting portion 5b of the through hole, the tip surface 6b of the protruding portion of the first mold (preferably the cavity) and the protruding portion of the second mold (preferably the core). A narrow hole corresponding to the portion of contact with the tip surface 7b is formed.

(Manufacturing process)
The method of the present invention includes a step of introducing a resin into a mold to obtain a molded product and a step of obtaining a plated layer, wherein the step of obtaining the plated layer creates the through hole from the back surface of the molded product. An electroless plating process that forms an electroless plating layer that passes through and connects to the surface, and an electroless plating that forms an electroless plating layer by performing electroless plating on the electroless plating layer using the electroless plating layer as a passage for current. Including the process. In one embodiment, two-color molding is used to form a molded product having through holes using two pairs of cavities and cores, and electroless plating is performed to pass through the through holes from the back surface of the molded product. It includes an electroless plating step of forming an electroless plating layer connected to a portion of the surface to be plated and an electroplating step of forming an electroplating layer using the electroless plating layer as a current passage.

(Molding process)
Next, the process of molding the molded product will be described.

As the molding method, any known molding method can be used as the molding method for the resin molded product. A known molding method is preferable as a molding method for the thermoplastic resin. For example, injection molding, extrusion molding, press molding and the like can be mentioned. Injection molding methods are particularly preferred.

For example, the molded product of the present invention can be molded by injection molding of a thermoplastic resin.

The molded product of the present invention can be molded by so-called multicolor molding (for example, two-color molding or three-color molding). The molding method of the present invention is preferably two-color molding or three-color molding.

In the present specification, multicolor molding means molding using a plurality of types of resins. Two-color molding means molding using two types of resin materials. Three-color molding means molding using three types of resins. The plurality of types of resins used in multicolor molding such as two-color molding or three-color molding may have different colors or may have the same color. Further, the resins may be different, or the resins may be the same but only the additives may be different.

In the manufacturing method of the present invention, for example, two-color molding according to the following procedure can be performed.

(1) A primary molding step of introducing a first resin between a first mold for primary molding and a second mold for primary molding to form a primary resin molded product. I do.

(2) A primary resin molded product is placed between the first mold for secondary molding and the second mold for secondary molding, and the second resin is introduced into the gap portion to be second. A secondary molding step of molding a secondary resin molded product is performed.

In such a two-color molding step, a conventionally known manufacturing apparatus for two-color molding can be used. For example, after the resin is injected from the injection machine attached to the second mold for the primary molding and the primary molding is completed, the first mold for the primary molding is automatically moved and remains as it is. There is a well-known device for performing secondary molding by injecting resin from an injection machine attached to the second mold of secondary molding by closing the mold so as to face the second mold for secondary molding. , Such an apparatus can be suitably used for the manufacturing method of the present invention.

In one preferred embodiment of the present invention, a resin that can be electroless plated and a resin that cannot be electroless plated are used in combination in two-color molding.

Specifically, for example
(1) Primary resin molding by introducing a first resin (for example, a resin that cannot be electrolytically plated) between a first mold for primary molding and a second mold for primary molding. The primary molding step of molding the product, and (2) the primary resin molded product is placed between the first mold for the secondary molding and the second mold for the secondary molding, and a gap is formed. A second molding step of introducing a second resin (for example, a resin capable of electroless plating) into the portion to mold the second resin molded product is performed.

Although the primary molding step and the secondary molding step can be performed completely separately, it is preferable to use some equipment for both steps in terms of production efficiency.

For example, the first mold for the primary molding can also be used as the first mold for the secondary molding. In this case, the secondary molding can be performed together with the second mold for the secondary molding while the primary molded product is held in the first mold for the primary molding.

In one embodiment, between the first mold for primary molding (eg, core) and the second mold for primary molding (eg, cavity), from the first injector to the first. The resin of 1 is introduced to mold the primary molded product. After that, the second mold is separated from the first mold and the primary molded product, and the primary molded product is held in the first mold. After that, the first mold holding the primary molded product is moved to a place where the secondary molding is performed.

Here, a second mold (for example, a cavity) for secondary molding is attached to the second injection machine for injecting the second resin. Then, the second mold for the secondary molding and the first mold holding the primary molded product are combined and the mold is closed. Then, the second resin is injected from the second injection machine to mold the secondary molded product. Since the second mold resin is injected while the primary molded product is present in the mold, a molded product in which the first resin and the second resin of the primary molded product are bonded can be obtained.

When performing two-color molding, it is possible to inject each resin using one injection machine, but it is preferable to inject each resin using two injection machines. When injecting each of the two types of resin with one injection machine, it is necessary to perform a process of changing the resin, and at that time, it is necessary to clean the inside of the injection machine, resulting in low production efficiency. There is a drawback that it will end up. However, if two injection machines are used, it is not necessary to change the resin for each injection machine, so that this drawback is not present and the production efficiency can be increased.

In a preferred embodiment of the present invention, a molding system including two injection cylinders in one molding machine is used. By injection molding two types of molding materials in order from two injection cylinders and heat-sealing them in a mold, an integrally molded product using the two types of materials can be made. In a more preferred embodiment, the two injection cylinders eject a resin that cannot be electroless plated (eg, polycarbonate) and a resin that can be electroless plated (eg, ABS). In the two-color molded product thus obtained, it is possible to obtain a selective plating molded product in which only the portion of the resin (for example, ABS) that can be electroless plated is plated.

Specifically, for example, the primary side plasticizing device, the injection cylinder and the fixed side mold, and the secondary side plasticizing device, the injection cylinder and the fixed side mold are connected to the fixed platen. The movable platen and the reversing platen are arranged at positions facing the fixed platen, and the two movable side molds A and B are arranged on the reversing platen. The mold is closed and a resin material (for example, polycarbonate) is injected from the primary injection cylinder to mold the primary molded product. After opening the mold, remove the runner. Then, while the primary molded product is held in the movable mold A, the reversing plate is inverted so that the movable mold A faces the secondary plasticizing device, the injection cylinder, and the fixed mold. .. At the same time, the movable side mold B is faced with the primary side plasticizing device, the injection cylinder and the fixed side mold. A resin material for secondary molding (for example, ABS) is injected from the secondary injection cylinder into the space between the movable mold A and the primary molded product and the fixed mold by closing the mold. Obtain a secondary molded product. Here, at the same time as the injection from the secondary side injection cylinder, the resin material for primary molding is injected from the primary side injection cylinder into the space between the movable side mold B and the primary side fixed side mold. Then, another primary molded product can be obtained at the same time.

(Plating process)
In the method of the present invention, the obtained molded product is plated.

The method of forming the plating layer on the surface of the molded product can be performed according to a conventionally known method. For example, a plating layer is formed on the surface of a molded product by performing (a) an electroless nickel plating step and (b) an electroplating step.

(A) Electroless nickel plating process First, the molded product is washed with water, and a metal plating layer is formed on the surface of the molded product by electroless nickel plating (chemical plating).

Electroless plating can be performed as follows.

Etching process:
The molded product is immersed in an aqueous solution of chromic anhydride and sulfuric acid at a predetermined temperature, and then washed with water to roughen the surface.

Catalist (catalyzer) process:
After immersing the molded product in an aqueous solution of palladium chloride, stannous chloride and hydrochloric acid, the molded product is washed with water to adsorb palladium on the surface of the molded product.

Accelerator process:
The molded product is immersed in an aqueous solution of hydrochloric acid, washed with water, and tin adsorbed together with palladium in the catalyst process is dissolved and removed with hydrochloric acid.

Electro-field plating layer forming process:
A mixed solution for electroless plating containing metal ions (eg, nickel, copper, etc.) and a reducing agent (eg, formalin, Rossell salt, phosphinate, etc.) is prepared. The molded product is immersed in this mixed solution. By reacting the metal ion with the reducing agent, a metal (for example, nickel, copper, etc.) is deposited on the surface of the molded product. Then, if necessary, it is washed with water and dried to obtain a molded product in which a metal adheres to the surface and an electric field-free plating layer is formed. Specific examples of the mixed solution containing metal ions and a reducing agent include a solution obtained by mixing a metal such as nickel or copper with formarin, Rossell salt, caustic soda, sodium hypophosphite, ammonia, water and the like, and nickel sulfate. , A mixture of sodium phosphinate, phosphoric acid and water is known.

By the method described above, an electroless plating layer of about 0.1 μm to 0.3 μm is formed.

(B) Electroplating step Next, electroplating can be performed on the electroless plating layer as follows. For example, nickel plating, chrome plating, or chrome alloy plating can be performed after copper plating as shown below.

First, a copper plating layer is formed on the surface of the electroless plating layer by electroplating.

The thickness of the copper-plated layer is usually 5 μm to 50 μm.

The copper plating conditions can be as follows.

The molded product is immersed in a copper sulfate bath having a concentration of 60 to 250 g / l and sulfuric acid having a concentration of 80 to 200 g / l at 10 to 30 ° C. to a cathode current density of 0.5 to 5 A / dm ² . And plate.

Next, a nickel layer is formed on the surface of the copper plating layer by electroplating.

That is, the molded product is immersed in a mixed solution containing nickel sulfate, nickel chloride, boric acid, and a brightener, treated under predetermined voltage and current conditions, and then washed with water to form a nickel film on the surface of the molded product.

Next, a chromium layer or a chromium alloy layer is formed on the surface of the nickel layer by electroplating.

The composition of the plating solution is, for example, at least one such as chromium sulfate (trivalent), chromium acetate (trivalent), chromium nitrate (trivalent), chromium chloride (trivalent), or chromium bicarbonate (trivalent). Can be used.

The present invention will be described in more detail by the following examples, but the present invention is not limited to the following examples.

(Example 1)
Using an injection molding system for two-color molding, a push button cover member for an automobile hazard lamp switch having a symbol as shown in FIG. 6 displayed on the surface was manufactured by the following procedure.

(Molding of primary molded product)
An injection molding machine for primary molding was prepared. Cores and cavities were attached to the injection molding machine as first and second molds for primary molding. A first injector was connected to the cavity.

The core and cavity were closed and a polycarbonate resin material containing a red colorant was injected from the injector to form the primary molded article. As a result, the first surrounding portion 31 and the second surrounding portion 32 were formed.

The cavity was separated from the core to obtain a primary molded product held in the core.

(Molding of secondary molded product)
The secondary molding was performed while the primary molded product obtained by the primary molding was held by the core. That is, the core of the primary molding was used as it was as the first mold for the secondary molding.

A cavity to be a second mold for secondary molding was prepared. A second injector was connected to the cavity.

The core holding the primary part was opposed to the cavity. The core and cavity were closed, and the ABS resin material was injected from the injection machine to mold the secondary molded product.

The cavity was separated from the core to obtain a secondary molded product held in the core.

In the molded product, a first through hole 51 was formed at the boundary surface between the first island-shaped portion and the first surrounding portion. Further, a second through hole 52 was formed at the boundary surface between the second island-shaped portion and the second surrounding portion. The first through hole and the second through hole had a front side portion, a back surface side portion, and a connection portion as shown in FIG. 3, respectively. The shape of the cross section parallel to the surface of the front surface side portion of the through hole is a rectangle with a width of about 1 mm and a length of about 2 mm, and the shape of the cross section parallel to the surface of the back surface side portion of the through hole is about 1 mm wide and about 2 mm long. It was a rectangle with a width of about 2 mm, and the connecting portion of the through hole was a rectangle with a width of about 0.05 mm and a length of about 2 mm.

(Electroless plating)
After washing the secondary molded product with water, electroless plating was performed as follows.

(1) Etching Step The surface of the molded product was etched by immersing the molded product in an etching solution having the following composition at about 65 ° C. for about 10 minutes.

<Etching liquid composition>
Chromic acid approx. 400 g / dm ³
Sulfuric acid about 400 g / dm ³ .

(2) Catalyst step Next, the molded product is immersed in a catalyst solution having the following composition at about 35 ° C. for 2 minutes, and further immersed in an accelerator solution at 40 ° C. for 3 minutes on the roughened surface. Palladium as a metal catalyst nucleus was attached to the metal catalyst.

<Catalyst liquid composition>
Palladium chloride about 0.1 g / dm ³
Stannous chloride approx. 10 g / dm ³
Hydrochloric acid about 250 dm ³ / dm ³ .

(3) Electroless Metal Plating Step Next, an electroless nickel plating bath (30 ° C.) shown below was used to form a nickel plating layer having a thickness of about 0.2 μm.

<Electroless nickel plating composition>
Nickel sulfate approx. 20 g / dm ³
Sodium phosphinate approx. 10 g / dm ³
Citric acid about 30 g / dm ³ .

(Electroplating layer forming process)
Next, the product after the electroless plating was sequentially immersed in the electrolytic plating solutions (a) to (c) having the following compositions to form three electroplating layers on the surface of the electroless plating layer on the surface.

<Composition of electrolytic plating solution>
(A) Nickel-plated nickel sulfate 280 g / dm ³
Nickel chloride 50g / dm ³
Boric acid 30g / dm ³
(B) Copper-plated copper sulfate 200 g / dm ³
Sulfuric acid 80g / dm ³
Brightener Appropriate amount (c) Chromium plating Trivalent chrome plating solution Envirochrome, Twilight chrome (manufactured by MacDermid Japan Co., Ltd.), Top Fine chrome (manufactured by In The Back Pharmaceutical Industry Co., Ltd.), etc.

(Product evaluation)
In the product obtained by the above method, the surface of the ABS resin portion of the upper surface and the side surface of the molded product was all well covered with the plating layer. Further, no plating layer was formed on the surface of the polycarbonate resin portion.

A photograph of the portion where the triangle on the surface of the obtained product is displayed is shown in FIG.

As a comparison, a photograph of the triangular part of the molded product in which a notch is formed in the triangle on the surface of the molded product having no through hole and the notch is plated as a conduction portion to the island-shaped portion is shown. 14 is shown.

As shown in FIG. 14, the formation of the notch significantly impaired the appearance of the triangle. However, as shown in FIG. 13, in the molded article of the present invention, the appearance of the triangle was not substantially impaired. The through hole was completely inconspicuous when observed from above. Careful observation with the naked eye did not confirm the presence of through-holes.

As described above, according to the present invention, it was confirmed that the plating layer can be formed on the island-shaped portion without adversely affecting the appearance of the symbols and the like.

As the conditions and materials used for electroless plating and electroplating, various conditions and materials are known to those skilled in the art, and various conventionally known conditions and materials other than the conditions and materials specifically described above are not known. The electroless plating layer and the electroplating layer can be similarly obtained by appropriately adopting the conditions and materials of the electrolytic plating method and the conventionally known electroplating methods and materials.

As described above, according to the present invention, there is provided a molded product in which island-shaped portions such as symbols are electroplated, the appearance is not impaired, and the molded product can be mass-produced. INDUSTRIAL APPLICABILITY According to the present invention, a manufacturing method capable of mass-producing such a molded product is provided.

The molded product of the present invention can be used particularly for interior parts and exterior parts of automobiles.

As described above, the present invention has been exemplified by using the preferred embodiment of the present invention, but the present invention should not be construed as being limited to this embodiment. It is understood that the invention should be construed only by the claims. It will be understood by those skilled in the art that from the description of the specific preferred embodiments of the present invention, the equivalent scope can be carried out based on the description of the present invention and common general technical knowledge. The patents, patent applications and documents cited herein are to be incorporated by reference in their content as they are specifically described herein. Understood.

1,11,12 Molds 2, 2c, 2d Island-shaped part 21 First island-shaped part 22 Second island-shaped part 3, 3c, 3d Surrounding part 31 First surrounding part 32 Second surrounding part 4 Periphery Part 5 Through hole 5a Front side part of through hole 5b Connection part of through hole 5c Back side part of through hole 51 First through hole 52 Second through hole 6 First mold 6a Protruding part 6b of first mold Tip surface of the protruding part of the first mold 7 Second mold 7a Protruding part of the second mold 7b Tip surface of the protruding part of the second mold 81 Number "0" attached to the surface of the molded product
82 Number "8" attached to the surface of the molded product

Claims (16)

A method for producing a resin molded product having a surface that is at least partially plated.
The molded product has a through hole leading from the back surface of the molded product to the partially plated portion of the front surface.
The method includes a step of introducing a resin into a mold to obtain a molded product and a step of obtaining a plated layer.
Here, the step of obtaining the plating layer is an electroless plating step of forming an electroless plating layer from the back surface of the molded product to the front surface through the through hole by electroless plating, and the electroless plating layer. It includes an electroplating step of forming an electroplating layer by electroplating on the electroless plating layer using it as a current passage.
Here, the through hole has a front surface side portion and a back surface side portion, and a connection portion connecting between the front surface side portion and the back surface side portion.
Here, the width in the cross section parallel to the surface of the connection portion is 5 μm to 3 mm .
The width of the surface side portion in the cross section parallel to the surface is 0.5 mm or more, and the width is 0.5 mm or more.
The width of the back surface side portion in a cross section parallel to the front surface is 0.5 mm or more .
Method. The method according to claim 1.
In the step of obtaining the molded product, a first mold having a projecting portion for forming a front surface side portion of the through hole and a second mold having a projecting portion for forming a back surface side portion of the through hole. Type is used,
When the first mold and the second mold are closed, a part of the tip surface of the protruding portion of the first mold and a part of the tip surface of the protruding portion of the second mold come into contact with each other. The protruding portion of the first mold and the protruding portion of the second mold are arranged, and the tip of the protruding portion of the second mold is in contact with a part of the tip surface of the protruding portion of the first mold. A portion of the surface forms the connection.
Method. The method according to claim 1 or 2.
The width in the cross section parallel to the surface of the connection portion is 5 μm to 0.5 mm .
Method. The method according to any one of claims 1 to 3, wherein the width in a cross section parallel to the surface of the hole of the connection portion is 0.05 mm to 0.15 mm. The method according to any one of claims 1 to 4.
The molded article has, on its surface, a plated first portion, an unplated second portion, and a plated third portion.
The second portion surrounds the first portion, the third portion is located outside the second portion and is not in contact with the first portion.
The through hole leads from the back surface of the molded product to the first portion.
Method. The method according to any one of claims 1 to 5.
The process of molding the molded product
A primary molding step of introducing a first resin between a first mold for primary molding and a second mold for primary molding to form a primary resin molded product, and a first. A primary resin molded product is placed between a first mold for secondary molding and a second mold for secondary molding, and a second resin is introduced into a gap portion to form a secondary resin. Includes a secondary molding step to mold the product
The first resin is a resin that cannot be electrolessly plated, and the second resin is a resin that can be electrolessly plated.
In the electroless plating step, an electroless plating layer is formed on the second resin.
Method. The method according to claim 6, wherein the connecting portion connecting the front surface side portion and the back surface side portion of the through hole exists at the boundary portion between the first resin and the second resin. Claims 6 to 7, wherein the first resin is a polycarbonate resin, the second resin is an ABS resin, and the primary molding step and the secondary molding step are performed by injection molding. The method according to any one of the above. The method according to any one of claims 1 to 8, wherein the molded product is a molded product for vehicle interior. The method according to any one of claims 6 to 9.
The primary molding step and the secondary molding step are injection molding steps, respectively.
The first mold for the primary molding is a cavity, and the second mold for the primary molding is a core.
The first mold for the secondary molding is a cavity, and the second mold for the primary molding is used as the second mold for the secondary molding after the primary molding. Will be
Method. A resin molded product with through holes
A plating layer is formed from the back surface of the molded product to the surface of the molded product through the inner surface of the through hole.
The through hole has a front surface side portion and a back surface side portion, and a connection portion connecting between the front surface side portion and the back surface side portion.
Here, the width in the cross section parallel to the surface of the connection portion is 5 μm to 3 mm .
The width of the surface side portion in the cross section parallel to the surface is 0.5 mm or more, and the width is 0.5 mm or more.
The width of the back surface side portion in a cross section parallel to the front surface is 0.5 mm or more .
Resin molded product. The resin molded product according to claim 11.
The width in the cross section parallel to the surface of the connection portion is 5 μm to 0.5 mm .
Resin molded product. The resin molded product according to claim 11 or 12, wherein the width in a cross section parallel to the surface of the hole of the connection portion is 0.05 mm to 0.15 mm. 13. Resin molded product. The resin molded product according to claim 14, wherein the island-shaped portion is formed of ABS resin and the surrounding portion is formed of polycarbonate resin. 14. The resin molded product described in.

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