JP2022091554A - Resin composite member - Google Patents

Abstract

To provide a resin composite member capable of preventing poor appearance without increasing a joining step.SOLUTION: A resin composite member 20 is composed of a first resin material 22, and a second resin material 24 integrated with the first resin material 22 by insert injection molding. The second resin material 24 has a joint part 26 overlapped on a rear face 22b of the first resin material 22 and joined to the rear face 22b, and a body part 28 connected to the joint part 26. The second resin material 24 is provided with an adhesion part 32 separated from the body part 28 and adhering to an edge face 22a of the first resin material 22 by a groove 30 opened on a surface 24a and formed along the edge face 22a of the first resin material 22 so as not to be separated from the edge face 22a of the first resin material 22 due to deformation of the body part 28 after injection molding.SELECTED DRAWING: Figure 1

Description

The present invention relates to a resin composite member made of a plurality of resin materials having different characteristics.

Conventionally, resin composite members that combine resin materials molded from resins with different properties (mechanical properties such as strength, hardness, elasticity, shrinkage rate, etc., or chemical properties such as heat resistance) have been used for automobiles. It is used for parts, electrical / electronic equipment parts, OA-related parts, various industrial miscellaneous goods parts, and the like. In Patent Document 1, the characteristics differ depending on the insert injection molding in which the first resin material is placed in the cavity of the injection molding mold and the thermoplastic resin is injected into the cavity to form the second resin material. A resin composite member in which a first resin material and a second resin material are integrated is disclosed.

Japanese Unexamined Patent Publication No. 2013-2461414

Since the resin composite member formed by the insert injection molding has a low bonding strength between the first resin material and the second resin material, in Patent Document 1, the first resin material and the second resin are used by a laser. Since the material is further bonded, it is pointed out that the joining process is increased and a separate laser welding device is required.

Here, as shown in FIG. 4, a part of the second resin material 12 is overlapped and joined to the back surface of the first resin material 10, and the end faces 10a, 12a of both resin materials 10, 12 are abutted against each other. In the resin composite member 14 in the form of being joined together, both resin materials 10, A gap 16 is created between the end faces 10a and 12a of the twelve. In particular, in insert injection molding, the shrinkage of the second resin material 12 to be injection-molded is larger than that of the first resin material 10 arranged in the cavity, so that the end face 10a of the first resin material 10 is used. The end faces 12a of the second resin material 12 contract (deform) in the direction in which they are separated from each other, and a gap 16 is generated between the end faces 10a and 12a. Then, when the surface to be the design surface of the resin composite member 14 in which the gap 16 is generated is painted in this way, the diluent or air contained in the paint enters the gap 16, and the diluent or air heat-drys the paint. Occasionally, it may volatilize or thermally expand, resulting in poor appearance such as paint cracking and paint swelling.

That is, an object of the present invention is to provide a resin composite member capable of preventing appearance defects without increasing the joining process.

In order to overcome the above-mentioned problems and achieve the intended purpose, the first invention of the present application is described.
A resin composite member in which a first resin material and a second resin material having a shrinkage ratio different from that of the first resin material are bonded to each other.
The gist is that the second resin material has a groove formed along the joint surface to which the first resin material is joined.
As described above, since the second resin material has a groove formed along the joint surface to which the first resin material is joined, the influence of shrinkage due to cooling and curing after injection molding is the second effect. It is possible to prevent the resin material from reaching the portion to be joined to the first resin material by the groove, and it is possible to prevent the joint surface of the second resin material from being separated from the first resin material. Further, when painting so as to cover the joint portion between the two resin materials, the diluent or air contained in the paint does not enter between the joint surfaces of the first resin material and the second resin material, so that the paint is used. Diluents and air do not volatilize or expand thermally during heat drying, and it is possible to prevent the occurrence of poor appearance such as paint cracking and paint swelling. Further, in order to increase the bonding strength between the bonding surfaces of the first resin material and the second resin material, a step of bonding by another means is not required.

The second invention is
The gist is that a coating film is formed so as to cover the joint portion between the first resin material and the second resin material and the groove.
In this way, since the coating film is formed so as to cover the joint portion between the two resin materials and the groove, the appearance is not impaired by the groove.

The third invention is
The gist is that the depth of the groove is formed so as to be equal to or greater than the width of the joint surface in the depth direction of the groove.
In this way, since the groove depth is formed so as to be equal to or greater than the width of the groove in the depth direction of the joint surface, the influence of the difference in shrinkage ratio between the two resin materials is the first effect of the second resin material. It is possible to more effectively prevent the portion to be joined to the resin material of.

According to the present invention, it is possible to prevent the occurrence of poor appearance when painted without increasing the joining process.

It is a schematic diagram which shows the resin composite member which concerns on Example, (a) is the perspective view in the state which the surface is not painted, (b) is the sectional view in the state where the surface is painted. It is explanatory drawing which shows the manufacturing process of the resin composite member which concerns on Example, (a) shows the state which installed the 1st resin material in the cavity of a molding die, (b) is a molding die. A closed state is shown, and (c) shows a state in which a thermoplastic resin is injected into the cavity to form a second resin material. It is sectional drawing which shows the resin composite member of the modification. It is explanatory drawing which shows the defect which occurs in the conventional resin composite member.

Next, the resin composite member according to the present invention will be described below with reference to the accompanying drawings with reference to suitable examples.

In the resin composite member 20 of the embodiment, as shown in FIG. 1, the first resin material 22 and the end surface (joint surface) 22a of the first resin material 22 are in close contact with each other on the opposite end surface (joint surface) 32a. It is composed of a second resin material 24 integrated by insert injection molding (injection molding). The first resin material 22 and the second resin material 24 are each molded from resin materials having different characteristics. In this embodiment, the second resin material 24 is made of a resin having a higher shrinkage rate than the first resin material 22, but the first resin material 22 has a shrinkage rate higher than that of the second resin material 24. It may be composed of a high resin material. The second resin material 24 includes a joint portion 26 that overlaps the back surface 22b of the first resin material 22 and is joined to the back surface 22b, and a main body portion 28 that is continuously provided to the joint portion 26. Further, in the second resin material 24, a groove 30 is formed along the end surface 22a of the first resin material 22 by opening to the surface 24a at a position separated from the end surface 22a of the first resin material 22. There is. Then, the contact portion 32, which is separated from the main body portion 28 by the groove 30 and the end surface 32a is joined to the end surface 22a of the first resin material 22, is deformed after injection molding of the main body portion 28 to form the first resin material 22. The second resin material 24 is provided so as not to be separated from the end surface 22a of the above.

The depth of the groove 30 in the second resin material 24 is not particularly limited, but the groove 30 is formed at a depth equal to or greater than the width in the depth direction of the groove 30 in the end surface 32a of the close contact portion 32. Can be done. The close contact portion 32 is connected to the main body portion 28 via the joint portion 26. Further, the unevenness 22d is formed on the end surface 22a of the first resin material 22, and the resin raw material of the second resin material 24 is formed by the unevenness 22d of the end surface 22a of the first resin material 22 in the insert injection molding. The end faces (joint surfaces) of the two resin materials 22 and 24 are joined to each other in a physically engaged state by entering the formed recess. Although the surface 22c of the first resin material 22 and the surface 24a of the second resin material 24 are flush with each other without a step in the vertical cross section, the first resin material 22 and the second resin material are flush with each other. The boundaries of the 24 may be stepped.

The resin composite member 20 is painted with a display as a design surface to form a coating film 33 having a predetermined thickness, and the coating film 33 covers the joint portions of the resin materials 22 and 24 and the groove 30. (See Fig. 1 (b)). The width M of the groove 30 is not particularly limited, but when the surface of the resin composite member 20 is painted to form the coating film 33, the paint can enter to fill the groove 30 and the main body portion. The size is set so that the influence of shrinkage (deformation) due to solidification on the 28 side does not reach the close contact portion 32. For example, the width M of the groove 30 is preferably 0.5 to 0.8 mm. That is, when the width M of the groove 30 is made smaller than 0.5 mm, the close contact portion 32 is pulled as the main body portion 28 shrinks, and the end surface 22a of the first resin material 22 is easily separated. Further, when the width M of the groove 30 is made larger than 0.8 mm, a dent is generated at the position of the groove 30 due to the shrinkage of the paint that has entered the groove 30, and the appearance is likely to be impaired. Further, the thickness N of the close contact portion 32 is such that the resin raw material can be filled in the cavity for forming the close contact portion 32 at the time of insert injection molding, and the close contact portion 32 is separated from the end surface 22a of the first resin material 22. The thickness is set so that the residual stress does not occur during injection molding. For example, the thickness N of the close contact portion 32 may be between 0.4 and 1.0 mm, and more preferably between 0.4 and 0.5 mm. That is, if the thickness N of the close contact portion 32 is smaller than 0.4 mm, the resin raw material cannot be filled in the cavity for forming the close contact portion 32, which makes it difficult to form the close contact portion 32. Further, when the thickness N of the close contact portion 32 is made larger than 1.0 mm, the residual stress generated in the close contact portion 32 becomes large, and it becomes easy to separate from the end surface 22a of the first resin material 22. Regarding the width M of the groove 30 and the thickness N of the close contact portion 32, appropriate values are set in the above range according to the difference in the characteristics (shrinkage rate) between the first resin material 22 and the second resin material 24. Just set it.

Examples of the first resin material 22 include a reinforcing fiber resin in which the reinforcing fiber is composed of carbon fiber, glass fiber, polyaramid fiber, alumina fiber, silicon carbide fiber, boron fiber, silicon carbide fiber and the like. Not limited. Examples of the second resin material 24 include polyolefin resins such as polyethylene and polypropylene, polystyrene, polycarbonate, acrylonitrile / styrene / butadiene block copolymers, general thermoplastic resins such as nylon, and ethylene / propylene block copolymers. Examples thereof include, but are not limited to, thermoplastic elastomers such as styrene / butadiene block copolymers, and polymer alloys thereof.

Next, a method for manufacturing the resin composite member 20 will be described with reference to FIG. First, as shown in FIG. 2A, a first resin material 22 molded by injection molding, extrusion molding, or the like is installed at a predetermined position of the lower mold 34a in the molding die 34, and FIG. 2B is shown. As shown in the above, the upper mold 34b is set in the lower mold 34a and the mold is closed. The lower mold 34a has a protrusion 36 for forming a groove 30 of the second resin material 24 at a position separated from the end surface 22a of the first resin material 22 installed in the lower mold 34a. It is provided along with.

FIG. 2C is obtained by injecting the resin raw material of the second resin material 24 from the gate (not shown) provided in the molding mold 34 into the cavity 38 defined in the molding mold 34. As shown in the above, the bonding portion 26 is bonded to the back surface 22b of the first resin material 22 by welding, and the end surface 32a of the adhesion portion 32 is bonded to the end surface 22a of the first resin material 22 by welding to adhere to the back surface 22a. The second resin material 24 in which the groove 30 is formed is formed. After cooling and solidifying the resin raw material, the mold is opened and the injection-molded product is taken out, so that the end faces of the first resin material 22 and the second resin material 24 shown in FIG. 1 are joined so as to be in close contact with each other. The integrated resin composite member 20 is obtained.

In the resin composite member 20 of the embodiment, the groove 30 is formed in the second resin material 24 along the end surface 32a of the close contact portion 32 to be joined to the end surface 22a of the first resin material 22. The groove 30 can prevent the influence of the shrinkage on the main body 28 side due to the cooling and curing of the second resin material 24 after the injection molding from reaching the close contact portion 32 of the second resin material 24. It is possible to prevent the end surface 32a of the close contact portion 32 in the second resin material 24 from being separated from the end surface 22a of the resin material 22 of 1. As a result, it is possible to prevent the resin composite member 20 from having a gap due to the shrinkage of the resin material, and it is possible to prevent the appearance from being impaired. Further, when the surface (design surface) of the resin composite member 20 is painted, the diluent or air contained in the paint does not enter between the both end faces 22a and 32a, and the diluent and air do not enter during the heat drying of the paint. Does not volatilize or thermally expand, and it is possible to prevent the occurrence of poor appearance such as paint cracking and paint swelling. That is, in order to increase the joining strength between the joining surfaces of the first resin material 22 and the second resin material 24 so that no gap is formed, a step of joining by another means is not required, and the manufacturing process is increased. There is nothing to do. Further, since the coating film 33 is formed so as to cover the joints of the two resin materials 22 and 24 and the groove 30, the appearance is not impaired by the groove 30.

Since the depth of the groove 30 of the second resin material 24 is formed so as to be equal to or greater than the width in the depth direction of the groove 30 in the end surface 32a of the close contact portion 32, the main body portion is formed over the entire close contact portion 32. The influence of the shrinkage on the 28 side can be effectively prevented, and the end surface 32a of the close contact portion 32 can be effectively prevented from being separated from the end surface 22a of the first resin material 22. Further, the width M of the groove 30 of the second resin material 24 is set to a dimension such that the influence of shrinkage (deformation) due to solidification on the main body portion 28 side does not reach the close contact portion 32, so that the insert injection is performed. In the molded resin composite member 20, it is possible to more effectively prevent the close contact portion 32 from being separated from the first resin material 22 due to the shrinkage of the main body portion 28. Further, the thickness N of the close contact portion 32 is set to a thickness that does not generate a residual stress of a size that causes the close contact portion 32 to be separated from the end surface 22a of the first resin material 22 during insert injection molding. It is possible to prevent the close contact portion 32 from being separated from the first resin material 22 due to the residual stress generated in the 32. Further, since the unevenness 23d is formed on the end surface 22a of the first resin material 22, the resin raw material of the second resin material 24 enters the recess of the end surface 22a and becomes a mechanically engaged state at the time of insert injection molding. Therefore, the bonding strength between the end surface 32a of the adhesion portion 32 and the end surface 22a of the first resin material 22 can be increased, and the adhesion portion 32 is further prevented from being separated from the first resin material 22 due to residual stress or shrinkage. be able to.

[Change example]
The present application is not limited to the configuration of the above-described embodiment, and other configurations may be appropriately adopted.
1. 1. In the embodiment, the second resin material is provided with a joint portion to be joined to the back surface of the first resin material, but as shown in FIG. 3, the first resin material 22 and the second resin material 24 are formed. , The end surface 22a of the first resin material 22 and the end surface 32a of the close contact portion 32 in the second resin material 24 may be joined.
2. 2. The groove may be open on either the front surface or the back surface of the second resin material, and the groove and the joint portion of both resin materials may be covered with a coating film.

22 1st resin material, 24 2nd resin material, 32a end face (joint surface), 30 groove 33 coating film

Claims (3)

A resin composite member in which a first resin material and a second resin material having a shrinkage ratio different from that of the first resin material are bonded to each other.
A resin composite member characterized in that a groove is formed in the second resin material along a joint surface to which the first resin material is joined. The resin composite member according to claim 1, wherein a coating film is formed so as to cover the joint portion between the first resin material and the second resin material and the groove. The resin composite member according to claim 1 or 2, wherein the depth of the groove is formed so as to be equal to or larger than the width of the joint surface in the depth direction of the groove.

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