JPH0741986A - Partial plating method for resin product - Google Patents

Abstract

PURPOSE:To prevent the contamination of electroplating soln. as far as possible and to surely prevent the formation of electroplating layer in a part where plating is not required. CONSTITUTION:An electroless plating layer 15 is formed in the entire part on the front surface of a grill body 2 exclusive of bottom 11a of line groove 11 having an approximately V-shaped section. The grill body 2 is then subjected to an electroplating stage consisting of plural stages. The electroless plating layer 15 of the part where the plating is not required is completely dissolved by the plating soln. having <= pH 4 after the lapse of a prescribed time in the first strike nickel plating stage of the electroplating stage. Strike nickel plating layers are formed on the front surfaces of the electroless plating layers 15 of the parts where the plating is required. The electroplating layer 16 is thereafter formed by subjecting the grill body to the respective plating stages of a copper plating stage, etc. Since the electroless plating layer 15 is not exposed after the copper plating stage, the dissolution of the layer in various kinds of the plating solns. does not arise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for partial plating of a resin product in which a plating layer is formed only on a portion of the surface of a resin base material which requires plating.

[0002]

2. Description of the Related Art Conventionally, as this type of technology, for example, there is one proposed in Japanese Patent Application No. 5-83603 of the present applicant. In this technique, as shown in FIG. 14, firstly, a groove 5 having a substantially V-shaped cross section is formed in the step portion 51 by die molding.
2 is formed into a ring-shaped grill body 53, and the grill body 53 is electroless plated. At this time, the groove 5
In the bottom portion 52a of No. 2, since the gap distance is narrow, plating is not performed, and the electroless plating layer 54 is formed in all the portions except these. Next, the grill body 53 on which the electroless plating layer 54 is formed is subjected to electroplating. For details of this electroplating process, strike nickel plating process,
It consists of multi-step processes such as copper plating process, nickel plating process and chromium plating process. Then, in the series of electroplating steps, the electroless plating layer 54 formed in the portion not requiring plating is gradually dissolved by the electroplating solution in each step. On the other hand, in the portion requiring plating, the electroplating layer 5 including a strike nickel plating layer, a copper plating layer, a nickel plating layer and a chrome nickel layer is formed on the surface of the electroless plating layer 54 by energization.
5 are sequentially formed. In this way, the portion where the plating layer 56 including the electroless plating layer 54 and the electroplating layer 55 is formed is covered with the electroforming mask 57, and coating is applied toward the exposed portion to form the coating layer 58.

Therefore, by going through the above steps, a front grill can be obtained in which the plating layer 56 is formed only in the necessary portions and the coating layer 58 is formed directly on the grill body 53 in the other portions.

[0004]

However, in the above-mentioned prior art, in the above series of electroplating steps, the electroless plating layer 54 formed in the portion not requiring plating is formed by the electroplating solution in each step. It was gradually being dissolved. For this reason, all the plating solutions in each electroplating process are contaminated with the metal ions forming the electroless plating layer 54. As a result, it is necessary to frequently replace the contaminated plating solution, resulting in an increase in cost.

Further, in the electroplating process, for example, when the electroless plating layer 54 still remains in a place where plating is not required at the stage when the copper plating layer or the like is formed thick, the groove groove is carefully formed. 52 by electroless plating layer 5
Despite dividing No. 4, the copper plating layer and the groove 5
There is a possibility that the electroless plating layer 54 separated by 2 may be connected. In such a case, the electroplated layer 55 was formed on the remaining electroless plated layer 54, and as a result, the desired partially plated product could not be obtained.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a resin product in which a plating layer is formed only on a portion of the surface of a resin base material which requires plating. In the partial plating method, it is possible to prevent the electroplating solution from being contaminated as much as possible, and it is possible to reliably prevent the electroplating from being formed in an unnecessary portion of the plating. To provide.

[0007]

In order to achieve the above object, the present invention provides a partial plating method for a resin product in which a plating layer is formed only on a portion of the surface of a resin base material which requires plating. In the surface of the base material, a groove having a substantially V-shaped cross section is formed in an annular shape or a part of an annular shape in a boundary line portion between a portion requiring plating and a portion not requiring plating. Formed on the base material that has undergone the electroless plating step, and an electroless plating step of forming an electroless plating layer on a portion of the surface of the base material other than the bottom portion of the groove. An electroplating step of electrically conducting a necessary portion of the electroless plated layer to form an electroplated layer made of a plurality of metal platings on the required portion of the electroless plated layer. And in the electroplating process Kicking, hydrogen ion exponent of the plating solution when applying the first metal plating is 4 or less, in the plating solution, and the gist of dissolving the electroless plating layer in a portion that does not require plating.

[0008]

According to the above structure, in the groove forming step,
A groove having a substantially V-shaped cross section is formed in a boundary line portion between a portion requiring plating and a portion not requiring plating on the surface of the base material so as to form an annular portion or an annular portion. Next, in the electroless plating step, an electroless plating layer is formed on the surface of the base material. At this time, the electroless plating layer is not formed because the plating solution does not reach the bottom of the groove. Therefore, the electroless plating layer is formed on the surface of the base material other than the bottom of the groove. Further, in the electroplating process, a portion of the electroless plating layer formed on the base material that needs plating is electrically conducted, and a portion of the electroless plating layer that requires plating has a plurality of metal plating layers. An electroplated layer of is formed. At this time, the electroless plating layer of the portion which does not require plating is gradually dissolved in the electroplating solution, and the electroplating layer is difficult to be formed thereon.

According to the present invention, in the electroplating step, the hydrogen ion index of the plating solution at the time of applying the first metal plating is 4 or less, and the electroless plating layer of the portion which does not require plating is the plating. Dissolved in solution. Therefore, the electroless plating layer is not dissolved in the metal plating solution in the subsequent electroplating process. Also,
In the subsequent electroplating process, the electroless plating layer is not exposed, so that the electroplating layer is not formed on the electroless plating layer in the portion that does not require plating.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a vehicle front grill 1 as a resin product will be described with reference to FIGS.

A front grill 1 as shown in FIG. 2 is mounted on the front surface of the vehicle. Figures 2, 3,
As shown in FIG. 7, the front grill 1 includes a front grill main body (hereinafter referred to as a grill main body) 2 as a base material made of ABS resin, and a part of its design surface, that is, a part of the front surface. The formed plating layer 3 (Fig. 3
Has a mesh-like portion) and a coating layer 4 applied and formed on a portion other than the plating layer 3 (excluding a part on the back side). More specifically, the front grill 1
Is a frame 5 having a substantially rectangular front shape, a plurality of sub-partition plates 6 extending in the horizontal direction within the frame 5, a plurality of connecting plates 7 extending in the vertical direction within the frame 5, and a mark plate (not shown) in the central portion. Mounting plate 8 and frame 5 for mounting
It has a main partition plate 9 extending from to the mounting plate 8. The plating layer 3 is formed mainly on the front side portion of the frame 5 and on the front side portion of the main partition plate 9. The coating layer 4 is formed mainly on the front side portions of the sub partition plate 6, the mounting plate 8 and the connecting plate 7.

FIG. 4 is an enlarged front view showing a part (α portion in FIG. 3) of the main partition plate 9, and FIG. 5 is an AA line in FIG.
It is a line sectional view. As shown in these figures and FIG. 7, in the front side portion of the grill body 2, at the boundary portion between the plating layer 3 and the coating layer 4, a front surface protruding vertically from the frame 5 and the main partition plate 9. The side step portion 10 is formed in an annular shape. A groove 11 having a substantially V-shaped cross section is formed in an annular shape (closed curve shape) in the front step portion 10 (see FIG. 3). Further, FIG. 6 shows a part of the back side of the frame 5 (β in FIG. 3).
It is a back view which expands and shows a (part). As shown in the figure, in the rear surface side portion of the grill body 2, a groove 13 having a substantially V-shaped cross section is formed in an annular shape at a boundary portion between the plating layer 3 and a portion where the plating layer 3 is not formed. (See FIG. 3). Further, on the rear surface side portion of the grill body 2, an electrode projection 14 is formed so as to project in the rear surface direction (vehicle rear direction) (see FIG. 3).

As shown in FIG. 7, the plating layer 3 comprises an electroless plating layer 15 and an electroplating layer 16. In this embodiment, the electroless plating layer 15 is made of nickel and has a thickness of about 0.3 to 0.4 μm. Further, the electroplating layer 16 is formed of a metal such as copper, nickel and chromium to a thickness of about 20 to 50 μm and has a multi-layer structure. More specifically, the electroplating layer 16 includes various metals in the order of a strike nickel plating layer, a copper plating layer, a semi-bright nickel plating layer, a bright nickel plating layer, and a chromium plating layer (all not shown) from the lower layer. It is formed by plating.

The widths W of the both grooves 11 and 13 are each "0.5 mm" and the depth D thereof is "0.5 mm". However, the width W is not particularly limited, but is preferably "0.2 mm" or more due to processing restrictions, and is preferably "1.0 mm" or less in order to improve the designability. The depth D is also not particularly limited, but is preferably "0.2 mm" or more due to the processing limitation and "0.
6 mm "or less is preferable. Further, the ratio of the depth D to the width W (D / W) is not particularly limited, either.
"1.0" or more is preferable.

Next, the mold 21 for molding the grill body 2 will be described. As shown in FIG. 8, the mold 21 includes a fixed mold 22 and a movable mold 23. A cavity 24 for molding the grill body 2 is formed by these two molds 22 and 23. However, in the movable die 23 (or the fixed die 22),
The projections 26 and the like for forming the are integrally formed.

Further, various plating solutions for forming each metal plating forming the electroplating layer 16 will be described. First, the plating solution for forming the strike nickel plating layer, which is the lowermost layer of the electroplating layer, has a solution temperature of 55 ° C., nickel sulfate 250 g / L, nickel chloride 170 g / L, hydrochloric acid 4 g / L, and boric acid 40 g / L. It contains L. The hydrogen ion index (hereinafter referred to as pH) of the solution is "1.5".

The plating solution used for forming the copper plating layer is copper sulfate 200 g / L, sulfuric acid 50 g / L, hydrochloric acid 0.
It contains 01 g / L and a slight amount of brightener. further,
The plating solution for forming the semi-bright nickel plating layer is
Nickel sulfate 280 g / L, nickel chloride 45 g / L,
It contains 40 g / L of boric acid and a slight amount of brightening agent. In addition, the plating solution for forming the bright nickel plating layer is nickel sulfate 240 g / L, nickel chloride 45 g /
L, boric acid 30 g / L and a slight amount of brightening agent and additives. In addition, the plating solution for forming the chromium plating layer contains chromic anhydride 250 g / L, sodium silicofluoride 10 g / L, and sulfuric acid 1 g / L.

Now, the operation and effect of manufacturing the front grill 1 will be described.
First, the melted ABS resin is injected and filled in the cavity 24 by a known die molding method (see FIG. 8). Once the resin has cooled and solidified, both molds 22,
Open 23 and take out the grill body 2. At this time, the two molds 22 and 23 are parallel to the mold opening direction, that is, the protrusion 26.
And so on. Therefore, the mold opening is not hindered by the protrusions 26 and the like, and the grill body 2 can be easily taken out. In this way, the grill main body 2 in which the grooved grooves 11 and 13 are annularly formed at predetermined locations is obtained.

Subsequently, the grill body 2 is immersed in an electroless plating solution to perform electroless plating. At this time, as shown in FIG. 9, the plating solution does not reach the bottom portions 11a and 13a of the both groove portions 11 and 13 because the gaps are small (however, in FIGS. 1 and 9 to 11, description will be made). For the sake of convenience, only the front side groove 11 will be described, but the same can be said for the rear side groove 13). Therefore, the bottoms 11a and 13a are not plated. In other words, the electroless plating layer 15 is formed on all portions of the surface of the grill body 2 except the bottom portions 11a and 13a.

Next, as shown in FIG. 1, the grill main body 2 on which the electroless plating layer 15 is formed is subjected to a strike nickel plating step, a copper plating step, a semi-bright nickel plating step,
It is subjected to an electroplating process consisting of a bright nickel plating process and a chrome plating process. That is, the main body 2 is dipped in a plurality of types of electroplating solutions for each of the above-mentioned steps, and the portions requiring plating (mainly the front side portion of the frame 5 and the front side portion of the main partition plate 9) are electrically connected. To conduct. At this time, the electrode projections 14 projectingly formed on the rear surface side portion of the grill body 2 serve as one electrode.

First, in the strike nickel plating step, the grill main body 2 on which the electroless plating layer 15 is formed is immersed in the above plating solution for forming the strike nickel plating layer for a predetermined time, and plating is required. Make the parts electrically conductive. Then, the electroless plating layer 15 formed in the portion that does not require plating
Is dissolved by the plating solution for the strike nickel plating layer. This is because the acidity of the solution is high (p
This is because H = *), and the plating layer in a portion not electrically connected is easily dissolved by the acid. On the other hand, in the portion requiring plating, the electroless plating layer 15
A strike nickel plating layer is formed relatively thin on the surface of the.

Then, in the copper plating step, the semi-bright nickel plating step, the bright nickel plating step and the chromium plating step, the same operations as above are performed. At this time, the electroless plating layer 15 in the portion that does not require plating is already dissolved by the plating solution for the strike nickel plating layer, and the surface of the electroless plating layer 15 in the portion that requires plating. A strike nickel plating layer is formed on. Therefore, the electroless plating layer 15 is not exposed in various steps after the copper plating step. Therefore, the electroless plating layer 15 is not dissolved in the plating solution in various steps after the copper plating step. As a result, it is possible to prevent each plating solution from being contaminated.

Further, since the electroless plating layer 15 is not exposed, the electroplating layer 16 is not formed on the electroless plating layer 15 in a portion which does not require plating. Therefore, it is possible to prevent the plating layer 3 from being formed in a portion that does not require plating, and the short-circuit between the grooves 11 and 13 from occurring.

Then, as shown in FIG. 10, the electroplating step 16 including the various steps described above is performed to form the electroplating layer 16 having the above-described multilayer structure (lower side of the figure). In this way, the grill body 2 in which the electroless plating layer 15 and the electroplating layer 16 (plating layer 3) are formed is formed only in the portion that requires plating.

Thereafter, as shown in FIG. 11, the plating layer 3
The formed portion of is covered with an electroformed mask 27 as a cover. That is, the electroformed mask 27 is a metal plate having a thickness of “several mm” and has a shape conforming to the shape of the front grill 1. In addition, the electroforming mask 27
An opening 28, which is opened only in a portion necessary for forming the coating layer 4, is appropriately formed in the. By covering the electroformed mask 27, a portion necessary for forming the coating layer 4 is exposed from the opening 28.

Then, as shown in FIG. 12, spray coating is applied to the exposed portion outside the same. By this coating, the coating film layer 4 is formed on the required portions of the coating film. On the other hand, the coating layer 4 is formed on the portion covered with the electroforming mask 27.
Are not formed.

After the coating layer 4 is formed, as shown in FIG. 7, the coating of the electroformed mask 27 is released to obtain the front grill 1 described above. That is, the plating layer 3 is provided mainly on the front side portion of the frame 5 and on the front side portion of the main partition plate 9, and the sub partition plate 6 and the mounting plate 8 are provided.
Further, the front grill 1 having the coating layer 4 mainly on the front side portion of the connecting plate 7 can be obtained.

As described above, according to this embodiment,
When forming the electroless plating layer 15 described above, the groove 1
The electroless plating layer 1 is formed on the bottom portions 11a and 13a of the electrodes 1 and 13.
5 is not formed. Therefore, when the electroplating layer 16 is formed, only the portion requiring plating is electrically conducted. That is, the electroless plating layer 15 formed in the portion that does not require plating is dissolved by the electroplating solution. Further, the electroplating layer 16 having the above-described multilayer structure is formed on the surface of the electroless plating layer 15 in the portion requiring plating.

Here, in the electroplating process after the copper plating process, the electroless plating layer 15 in a portion not requiring plating has already been dissolved by the plating solution for the strike nickel plating layer. In addition, in the portion requiring plating, the surface of the electroless plating layer 15 is
A strike nickel plating layer is formed. Therefore, the electroless plating layer 15 is not exposed in various steps after the copper plating step. FIG. 13 is a graph showing the cumulative amount of electroless plating layer 15 dissolved in each plating solution in each step of the electroplating step in the present example (solid line) and the conventional technique (broken line). As is clear from the figure, unlike the conventional technique in which the electroless plating layer is gradually dissolved in the plating solution of each plating step, in this embodiment, all the electroless plating layers 15 are added to the plating solution of the strike nickel plating step. Are dissolved and not after that. That is, according to this example, the electroless plating layer 15 is not dissolved in the plating solution in various steps after the copper plating step. Therefore, it is possible to prevent each plating solution from being contaminated. As a result, it is not necessary to replace each plating solution due to contamination, and thus cost can be reduced.

Further, since the electroless plating layer 15 is not exposed, the electroplating layer 16 is not formed on the electroless plating layer 15 in a portion which does not require plating. Therefore, it is possible to prevent the plating layer 3 from being formed in a portion that does not require plating and short-circuiting between the grooves 11 and 13.

Furthermore, in the present embodiment, the plating layer 3 can be formed only in the necessary portion. Therefore, when forming the coating layer 4, without interposing a primer layer,
The coating layer 4 can be directly formed on the grill body 2. As a result, the step of forming the primer layer is unnecessary, so that it is possible to reduce the number of work steps and the cost. In addition, the electroplating layer 16 is formed on the entire surface of the grill body 2.
Since it is not necessary to form, the cost can be reduced accordingly.

In addition, in the front grill 1, the coating layer 4 is directly formed on the grill body 2. Therefore, the thickness of the portion is reduced by the amount that the plating layer 3 and the primer layer are not interposed. As a result, the thickness of the coating film layer 4 portion can be reduced, and the appearance quality can be improved. Further, since the coating layer 4 and the grill body 2 are both made of a resin material, the coating layer 4 can be firmly bonded to the grill body 2. Therefore, the durability of the coating layer 4 of the front grill 1 can be improved.

In addition, in this embodiment, the groove 11 on the front side serves as the boundary between the coating layer 4 and the plating layer 3. For this reason, the parting portion of the boundary portion is clearly formed instead of the zigzag shape. As a result, the parting line can be made clear and clear, and further, the appearance quality can be further improved.

The present invention is not limited to the above-described embodiments, but may be implemented as follows with a part of the configuration appropriately modified without departing from the spirit of the invention. (1) In the above embodiment, the electroplating process is composed of five processes including the strike nickel plating process, and the electroplating layer 16 made of a plurality of metal platings is formed. The order, the number of steps, the type of plating, and the like are not particularly limited as long as the process includes a plurality of steps. Therefore, if the pH of the plating solution in the first electroplating step is "4" or less,
For example, omit the strike nickel plating process,
It is also possible to change the order of the plating steps or to introduce another plating step.

(2) In the above embodiment, the present invention is embodied in the front grille 1 for a vehicle, but in addition to this, the outer cover for the vehicle door mirror bracket, the back panel, the louver, the pillar garnish, the quarter vent, It may be embodied as a mark plate or the like. Further, the present invention is not limited to the above resin products, and the present invention may be embodied in other resin products partially having a plating layer.

(3) In the above embodiment, the resin material constituting the base material is made of ABS resin. However, in addition to this, various resin materials such as polypropylene, polyphenylene oxide, polyamide, polysulfone, polyester, etc. May be used.

(4) In the above embodiment, the electroless plating layer 1
Although 5 is made of nickel, it may be made of copper or the like. (5) In the above-described embodiment, the die 21 is used to form the grooves 11, 1
3 is formed, but each groove is formed by an NC cutter,
It may be formed by post-processing using an ultrasonic cutter or the like.

(6) In the above embodiment, hydrochloric acid and boric acid are added to keep the pH of the plating solution in the strike nickel plating step at "4" or less.
It may be configured such that any acid such as praise, hydrofluoric acid, and sulfuric acid is added. The composition of each plating solution described in the above embodiment is not limited to the above.

[0039]

As described in detail above, according to the present invention,
In the partial plating method of the resin product in which the plating layer is formed only on the portion of the resin base material that requires plating, the contamination of the electroplating solution can be prevented as much as possible,
Moreover, there is an excellent effect that it is possible to surely prevent the electroplating from being formed on the unnecessary portion of the plating.

[Brief description of drawings]

FIG. 1 is a process chart showing the sequence of respective steps of an electroless plating process and an electroplating process in one embodiment of the present invention.

FIG. 2 is a front view showing a front grille according to an embodiment.

FIG. 3 is a view showing a plated portion of the front grille in one embodiment, and is a schematic view of the front grille developed on the front surface and the back surface.

FIG. 4 is an enlarged front view showing a part of the main partition plate of the front grille in one embodiment.

5 is a cross-sectional view taken along the line AA of FIG. 4 in one embodiment.

FIG. 6 is an enlarged back view showing a part of the frame of the front grill in one embodiment.

7 is a cross-sectional view showing an enlarged main part of FIG. 5 in one embodiment.

FIG. 8 is a cross-sectional view showing, in an enlarged manner, a part of a mold for molding the grill body in one embodiment.

FIG. 9 is a partial cross-sectional view showing a state in which electroless plating is applied to the grill body in the embodiment.

FIG. 10 is a partial cross-sectional view showing a state in which electroplating is performed on the grill main body on which the electroless plating layer is formed in one example.

FIG. 11 is a partial cross-sectional view showing a state in which an electroformed mask is coated on a portion of the grill body on which a plating layer is formed in one embodiment.

FIG. 12 is a partial cross-sectional view showing a state in which a coating layer is formed on a portion of the grill body where the plating layer is not formed, in one example.

FIG. 13 is a graph showing the cumulative dissolution amount of an electroless plating layer in each step of the electroplating step in one example.

FIG. 14 is a cross-sectional view of an essential part showing the vicinity of a groove of a front grill in a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Front grill as a resin product, 2 ... Grill main body as a base material, 3 ... Plating layer, 11, 13 ... Grooves, 11
a, 13a ... bottom part, 15 ... electroless plating layer, 16 ... electroplating layer.

Claims (1)

[Claims] 1. A partial plating method for a resin product, wherein a plating layer (3) is formed only on a portion of a surface of a resin base material (2) that requires plating, wherein the base material (2) ) In the boundary line between the portion requiring plating and the portion not requiring plating, a groove groove (11, 13) having a substantially V-shaped cross section is formed into an annular shape or a part of an annular shape. A step of forming a groove, and an electroless plating layer (1) on the surface of the base material (2) other than the bottom (11a, 13a) of the groove (11, 13).
5) and an electroless plating step of forming the electroless plating layer of the base material (2) that has been subjected to the electroless plating step. The electroless plating layer (1
5) An electroplating step of forming an electroplating layer (16) composed of a plurality of metal platings on the above-mentioned necessary plating portion, and a plating solution for applying the first metal plating in the electroplating step. The method of partially plating a resin product, wherein the hydrogen ion index of 4 is 4 or less, and the electroless plating layer (15) at a portion not requiring plating is dissolved in the plating solution.