JP2004050457A - Manufacturing method of composite containing soft polymeric body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a composite which can simply and efficiently coat an injection molded product with a sheet imparting a quality feeling or touch not obtained by injection molding. <P>SOLUTION: A soft polymer sheet 3 is intermittently supplied to the mold 5 of an injection molding apparatus 5 and a composite main body 2 is injection-molded so as to be integrated with the sheet 3. After injection molding, the unnecessary part of the soft polymer sheet 3 is cut with respect to the composite main body 2 to obtain a composite 1 wherein the surface of the composite main body 2 is coated with the soft polymer sheet 3. The manufacturing method is characterized in that, since a molten resin for molding the composite main body 2 is injected in a mold cavity under high pressure, the soft polymeric sheet 3 is pushed by the molten resin to be elastically deformed to conform to the curved surface of a cavity with a high fidelity, the composite 1 free from wrinkles on its soft polymeric sheet 3 can be manufactured simply and efficiently. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Field of the Invention]
The present invention relates to a composite in which the surface of a synthetic resin product is integrally coated with a soft polymer and a method for producing the composite.
[0002]
2. Prior Art and Problems to be Solved by the Present Invention
2. Description of the Related Art In order to change the feel and texture, the surface of a resin product is coated with a soft polymer in a layered manner.
Examples of such methods include a method in which a sheet member formed of a soft polymer is bonded to the surface of a resin product, and a method in which a resin product and a soft polymer are integrally formed by a two-color molding method.
However, when a sheet member formed of a soft polymer is adhered to a resin product, it takes time and skill to make the sheet member conform to the irregularities of the resin product, and wrinkles may occur and the commercial value may be lost. .
[0003]
On the other hand, the two-color molding method is a method of integrally injection-molding a product using two kinds of resins having different colors or different characteristics. After a soft polymer is formed in a layer by primary molding, a soft polymer is formed by secondary molding. A resin product can be molded integrally with the polymer layer.
However, an injection molding apparatus used for two-color molding requires two types of dies for primary molding and secondary molding. Further, after the primary molding is completed, the mold is opened, and while holding the molded article in one of the molds, the mold is turned, and the mold is clamped together with the mold for the secondary molding to perform the secondary molding. As a result, the molding apparatus becomes complicated, which is reflected in the product cost.
Further, even when it is desired to make the soft polymer layer thin, there is a problem that the layer cannot be made thin due to the flow of the molten resin into the cavity of the molding die.
The present invention is to clarify a composite which can solve the above-mentioned problem and whose surface is integrally coated with a soft polymer, and a method for producing the composite.
[0004]
[Means to solve the problem]
According to the method for producing the composite of the present invention, the soft polymer sheet (3) is intermittently supplied to the mold (5) of the injection molding apparatus, and the soft polymer sheet (3) is integrated with the soft polymer sheet (3). The main body (2) is injection-molded, and after the injection molding, unnecessary portions of the flexible polymer sheet (3) are cut off from the main body (2) to make the surface of the main body (2) soft. The composite (1) covered with the molecular sheet (3) is obtained.
[0005]
The composite of the present invention comprises a composite main body (2) made of a synthetic resin, and the surface thereof is integrated with the composite main body (2) to cover a soft polymer sheet (3). The flexible polymer sheet (3) covers the through hole (21) formed in the above.
[0006]
[Action and effect]
The mold for molding the composite (1) may be one type of mold having a cavity corresponding to the shape of the composite (1). As in the case of the two-color molding method, the mold for primary molding and the secondary molding are used. No two types of molds are required. Further, complicated and expensive equipment such as a two-color molding machine is not required. It is only necessary to add a feeding device for the soft polymer sheet (3) to a general injection molding machine.
Since the molten resin for forming the composite main body (2) is injected into the mold cavity at a high pressure, the soft polymer sheet (3) is elastically deformed by being pressed by the molten resin and faithfully conforms to the curved surface of the cavity. Along. For this reason, the composite (1) in which wrinkles are not generated in the soft polymer sheet (3) on the surface can be easily and efficiently manufactured.
[0007]
If the mold (5) is provided with a mold (53) capable of pressing the soft polymer sheet (3) from the molten resin injection side, the mold (53) allows the composite main body (2) to be pressed. A through hole (21) corresponding to the contour of the mold piece (53) is formed, and the through hole (21) is covered with the flexible polymer sheet (3). Therefore, if the composite main body (2) is a cabinet of a mobile phone and the through-hole (21) is a hole for an operation button, the soft polymer sheet (3) covers the operation button, and the through-hole ( 21) It is possible to prevent dust from entering through a gap between the operation button and the waterproof button by the soft polymer sheet (3).
The thickness of the flexible polymer sheet (3) can be freely selected as long as it can be along the curved surface of the mold cavity.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a case where the composite (1) of the present invention is applied to a cabinet of a mobile phone.
The cabinet is formed by combining the front cabinet (1a) and the rear cabinet (10). In the following description, the front cabinet is simply referred to as a cabinet.
The cabinet (1a) is formed by integrally covering a soft polymer sheet (3) over the entire surface of a cabinet body (2a), which is a composite main body (2).
The cabinet body (2a) is formed in a vertically long shape with a synthetic resin, and has a peripheral wall (20) all around the outer periphery.
The cabinet body (2a) has an operation section on one end side and a display section on the other end side. As shown in FIG. 2, a plurality of through holes (21) for opening push buttons (not shown) in the operation section are opened. A window (22) for exposing a liquid crystal display member (not shown) is opened in the section.
[0009]
The soft polymer sheet (3) is formed of a transparent polyurethane resin in the embodiment, and has a thickness of about 0.5 mm.
The soft polymer sheet (3) covers the entire surface of the cabinet body (2a) except for the window hole (22), and as shown in FIG. The hole (21) is covered with the soft polymer sheet (3).
The flexible polymer sheet (3) has, at a portion corresponding to the through-hole (21), a raised portion (31) which is slightly higher toward the outside of the hole (21). The central portion of 31) further has a raised protrusion (32).
[0010]
The cabinet (1a) is formed by the following method.
First, a long flexible polymer sheet (3) wider than the width of the cabinet (1a);
An injection mold (5) having a cavity corresponding to the cabinet (1a) is prepared.
One side of the soft polymer sheet (3) in contact with the cabinet body (2a) is subjected to a primer treatment as necessary. This means that the primer is thinly applied in order to improve the integration between the soft polymer sheet (3) and the material resin of the cabinet body (2a).
As shown in FIG. 3, the mold (5) has mold pieces (53), (53) and (54) for forming through holes (21) and (21) and a window hole (22) of the cabinet body (2a). As shown in FIG. 4, the height of the mold piece is determined so as to further press the soft polymer sheet (3) close to the wall surface of the cavity.
[0011]
As shown by a two-dot chain line in FIG. 3, the flexible polymer sheet (3) is intermittently interposed between the movable mold (52) and the fixed mold (51) in the mold open state by a feeding device (not shown). Send in.
The flexible polymer sheet (3) has the primer-treated surface facing the mold pieces (53), (53), and (54).
While the feeding of the flexible polymer sheet (3) is stopped, the movable mold (52) is closed and closed, and the molten resin is injected into the cavity from the cylinder (6) to remove the cabinet body (2a). Form.
[0012]
Since the molten resin is injected into the cavity at a high pressure, the soft polymer sheet (3) is elastically deformed by being pressed by the molten resin, faithfully follows the curved surface of the cavity, and does not wrinkle the sheet.
Further, as shown in FIG. 4, the distal end surfaces of the mold pieces (53), (53), and (54) projecting into the cavity are set to have a protruding height so as to compress the soft polymer sheet (3). Therefore, there is no gap between the flexible polymer sheet (3) and the tip surfaces of the mold pieces (53), (53), and (54) for the molten resin to enter. Therefore, burrs do not occur at the through-holes (21) and window holes (22) of the cabinet body (2a), and the hole edges can be formed sharply.
Since the opponent to be pressed by the mold pieces (53) and (54) is the soft polymer sheet (3) that is elastically deformed, a high precision is not required for the projecting height of the mold pieces (53) and (54).
[0013]
After the mold is opened, the feeding device (not shown) operates to move the soft polymer sheet (3) by one pitch.
The above cycle is repeated, and the cabinet main body (2a) is sequentially formed at equal intervals on the soft polymer sheet (3).
[0014]
As shown in FIG. 6, an unnecessary portion of the flexible polymer sheet (3), that is, an outer portion from the outer peripheral edge of the cabinet body (2a) and a window of the cabinet body (2a) are formed by a punching device (not shown). Cut the inner portion (30) from the edge of the hole (22). Thereby, the cabinet (1a) in which the surface of the cabinet body (2a) is covered with the soft polymer sheet (3) can be obtained.
A feel and texture that cannot be obtained by injection molding can be obtained by coating the soft polymer sheet (3).
[0015]
The raised portion (31) of the flexible polymer sheet (3) covers the through hole (21) for the operation button of the cabinet body (2a). In addition, it is possible to prevent the flexible polymer sheet (3) from being partially pulled and realize a smooth button operation.
[0016]
According to the method of manufacturing the cabinet (4), two types of molding dies for primary molding and secondary molding are not required as in the case of two-color molding, and complicated and expensive as in a two-color molding machine. It does not require any special equipment. It is only necessary to add a feeding device (not shown) for the soft polymer sheet (3) to a general injection molding machine.
[0017]
When two different types of resins are integrated by the conventional two-color molding method, performing the primer treatment on the surface of the primary molded resin member means that the resin member is held by one of the molds. Therefore, it is virtually impossible.
On the other hand, in the present invention, before supplying the flexible polymer sheet (3) to the mold (5), the flexible polymer sheet (3) can be subjected to a primer treatment in advance.
Therefore, in the present invention, when the cabinet main body (2a) is directly injection-molded on the soft polymer sheet (3), the bonding strength between the soft polymer sheet (3) and the cabinet body (2a) is not sufficient. At times, the soft polymer (42) is subjected to a primer treatment to increase the bonding strength between the soft polymer sheet (3) and the cabinet body (2a), and the soft polymer sheet (3) and the cabinet The reliability of integration of the main body (2a) can be improved.
[0018]
The description of the above embodiments is intended to explain the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims.
For example, when the flexible polymer sheet (3) is transparent, at least one of the inner surface and the outer surface of the sheet is provided, and when the flexible polymer sheet (3) is transparent, the outer surface of the sheet is provided. If the design and coloring by printing are given, the printing surface can be formed more efficiently than printing after completion of the product.
[Brief description of the drawings]
FIG. 1 is a perspective view of a cabinet of a mobile phone.
FIG. 2 is a sectional view taken along the line AA of FIG. 1;
FIG. 3 is an explanatory diagram of a method for manufacturing a cabinet.
FIG. 4 is a sectional view of a main part of a mold.
FIG. 5 is a perspective view of a state in which a cabinet body is formed on a flexible polymer sheet.
FIG. 6 is a perspective view showing a state in which an unnecessary portion of a soft polymer sheet is cut from a cabinet.
(1) Composite (1a) Cabinet (2) Main body of composite (2a) Cabinet body (3) Flexible polymer sheet (6) Mold

Claims (3)

The soft polymer sheet (3) is intermittently supplied to the mold (5) of the injection molding apparatus, and the composite body (2) is injection-molded so as to be integrated with the sheet (3). Unnecessary portions of the flexible polymer sheet (3) are cut from the composite body (2), and the surface of the composite body (2) is covered with the flexible polymer sheet (3). A) a method for producing a composite containing a flexible polymer. The mold (5) is provided with a mold piece (53) capable of pressing the soft polymer sheet (3) from the molten resin injection side, and the mold piece (53) penetrates the composite main body (2). The method according to claim 1, wherein a hole (21) is formed, and the through-hole (21) is closed by a flexible polymer sheet (3). A soft polymer sheet (3) covers the surface of the synthetic resin main body (2) integrally with the composite main body (2), and the through hole (21) opened in the composite main body (2) is soft. A composite covered with a polymer sheet (3).

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