JP5593998B2 - Manufacturing method of multicolor molded products - Google Patents

Description

The present invention relates to a method for producing a multicolor molded article.

  Conventionally, as a two-color molded product configured to include a first molded product and a second molded product made of a different material or the same type of material and having a different color, for example, the following patent document 1 is known. In such a two-color molded product, there is a problem that the resins do not adhere to each other at the boundary between the first molded product and the second molded product, and sufficient bonding strength cannot be obtained. For this reason, in Patent Document 1, a concave portion is formed in the first molded product, a convex portion that fits into the concave portion is formed in the second molded product, and the concave and convex portions are fitted into the concave and convex portions to contact the boundary. Thus, the bonding strength can be increased. Similarly, in Patent Document 2 below, a step is formed at the boundary between the first molded product and the second molded product to increase the contact area of the boundary.

Japanese Patent Laid-Open No. 4-193513 JP 2007-130914 A

  By the way, depending on the type of the two-color molded product, a groove is formed at the boundary between the first molded product and the second molded product, and a design is produced by blurring the boundary portion having a different color. In some cases, a so-called wood-grooved groove is formed. However, for example, when a bending stress is applied to the two-color molded product and the stress is concentrated in the groove portion which is a fragile portion, even if the contact area between the first molded product and the second molded product is increased, the There is a risk of separation of the first molded product and the second molded product.

  This invention is completed based on the above situations, Comprising: It aims at preventing the fracture | rupture of the groove part formed in the boundary of a 1st molded product and a 2nd molded product.

  The present invention includes a first molded product and a second molded product made of a different material or the same type of material and having a different color, and the first molded product and the second molded product. A manufacturing method of a multicolor molded product having a groove formed at the boundary, wherein the first core is pressed against a molding surface for molding the inner surface of the groove, and the second core is placed on the side surface of the first core. In a pressed state, a first molding space for molding the first molded product is formed, and a first molding step for molding the first molded product by injecting resin into the first molding space; Forming a second molding space by punching out both of the first core and the second core, and injecting a resin into the second molding space to mold a second molded product, The second molding space includes a die-cutting hole formed by die-cutting the second core from the inside of the first molded product. Can holes have a feature where being a dovetail groove-shaped inner diameter becomes larger toward the deeper from the boundary along the die cutting direction of the second core.

  If it does in this way, since there is a die-cutting hole and it is made into groove shape, it will become easy to carry out die-cutting of the 2nd core. Furthermore, since the second molded product is configured to include a portion filled inside the dovetail hole having a dovetail shape, the hole diameter is reduced in the direction in which the filled portion is removed, thereby exhibiting a retaining effect. By doing so, it does not easily come off from the inside of the first molded product, and the bonding strength at the boundary between the first molded product and the second molded product can be increased. Therefore, the breakage of the groove formed at the boundary between the first molded product and the second molded product can be prevented.

As an embodiment of the present invention, the following may be adopted.
The first core may enter the second molding space from one side molding surface that molds the outer surface of the inner wall of the groove portion and be pressed against the other molding surface that molds the inner surface of the inner wall of the groove portion. .

  If it does in this way, the 1st core can be made to enter into the 2nd molding space from one side molding surface, and can be pressed on the other side molding surface. Further, if the first core is pressed against the molding die for molding the inner surface of the groove portion from the side perpendicular to the fitting direction, the molding die may be deformed to the side, as described above. In this case, the first core can be pressed against the mold from the direction opposite to the protruding direction, so that the first core can be pressed strongly against the mold.

  The present invention also includes a first molded product and a second molded product made of a different material or the same type of material and having a different color, the first molded product and the second molded product. The second molded product is configured to include a retaining portion formed so as to protrude from the boundary to the inside of the first molded product, and a second molded product. The retaining recess that fits and fits with the retaining portion in the product is characterized in that the outer diameter increases from the boundary toward the back and is formed into a groove shape.

  According to such a configuration, since there is a retaining recess and it has a groove shape, the retaining portion and the retaining recess can be firmly bonded, and the bonding strength at the boundary between the first molded product and the second molded product is increased. Can do. Therefore, the breakage of the groove formed at the boundary between the first molded product and the second molded product can be prevented.

  According to the present invention, it is possible to prevent breakage of the groove formed at the boundary between the first molded product and the second molded product.

The perspective view which shows the door trim in embodiment. It is AA sectional view taken on the line in FIG. 1, Comprising: Section drawing which expanded and showed the groove part Sectional view of the internal structure of the groove seen from an oblique direction Sectional view showing the structure of the mold for forming the groove Sectional drawing which shows the state which advanced the 1st core and the 2nd core from the state of FIG. 4, and formed the 1st shaping | molding space. Sectional drawing which shows the state which inject | poured resin into the 1st shaping | molding space from the state of FIG. Sectional drawing which shows the state which made the 1st core and the 2nd core retreat from the state of FIG. 6, and formed the 2nd shaping | molding space Sectional drawing which shows the state which inject | poured resin into the 2nd shaping | molding space from the state of FIG. Sectional drawing which shows the state which removed the door trim from the state of FIG. Sectional drawing which shows the state which covered the skin material on the surface of the base material in FIG.

<Embodiment>
An embodiment of the present invention will be described with reference to the drawings of FIGS. In this embodiment, the door trim 10 attached to a vehicle door is illustrated as a two-color molded product. FIG. 1 is a perspective view of a door trim 10 of the present embodiment. As shown in FIG. 1, the door trim 10 includes a door trim main body 12 and an armrest 20 formed in a plate shape with a synthetic resin or the like. The armrest 20 is formed of a synthetic resin or the like, and is arranged so as to project to the vehicle interior side of the door trim main body 12. The door trim 10 includes an ornament 14, a speaker grill 16, a door pocket 18, and the like. At the boundary between the door trim main body 12 and the ornament 14, a groove portion 22 is recessed over the entire circumference.

  FIG. 9 is a cross-sectional view showing the two-color molded product 11 serving as both base materials 24 and 28. The boundary 34 is disposed near the center of the bottom surface 23 of the groove 22. At the interface 36 on the boundary base material 28 side at the boundary 34, a retaining portion 38 protrudes from the interface 36 toward the inside of the door trim base material 24. On the other hand, at the interface 40 on the door trim base 24 side at the boundary 34, a retaining recess 42 that fits and fits with the retaining portion 38 is provided. The retaining recess 42 is formed in a groove shape having an inner diameter that increases from the interface 40 on the door trim base 24 side toward the back (left side in the drawing). For this reason, in a state where the retaining portion 38 is joined to the retaining recess 42, it is restricted that the retaining portion 38 is easily detached from the retaining recess 42.

  Furthermore, as shown in FIG. 3, a plurality of joint portions by the retaining portion 38 and the retaining recess 42 are provided intermittently along the circumferential direction in which the groove portion 22 is formed. Therefore, the door trim base material 24 and the ornament base material 28 are firmly fixed over the entire circumference, and the bonding strength at the boundary 34 between the door trim base material 24 and the ornament base material 28 can be increased. Thereby, even if a bending stress is applied to the door trim 10 and the stress is concentrated on the groove 22, the door trim 10 can be prevented from being damaged at the boundary 34.

  Next, a configuration of a molding die for forming the groove 22 by two-color molding of the door trim base material 24 and the ornament base material 28 and a molding method thereof will be described with reference to FIGS. 4 to 9. As shown in FIG. 4, the mold for molding the groove portion 22 includes an upper mold 50, a lower mold 52 arranged to face the lower side of the upper mold 50, and a first medium incorporated in the lower mold 52. A core 54 and a second core 56 are provided.

  The lower mold 52 has a recessed portion recessed downward, and the lower surface 52A constituting the recessed portion is a surface on which the outer surface of the inner wall 22A of the groove portion 22 is molded. Further, the side surface 52 </ b> B constituting the concave portion is a surface for molding the outer surface of the side wall 22 </ b> B of the groove portion 22. On the other hand, the upper die 50 has a convex portion that enters the concave portion of the lower die 52, and the lower surface 50 </ b> A constituting the convex portion is a surface that forms the inner surface of the rear wall 22 </ b> A of the groove portion 22. Further, the side surface 50 </ b> B constituting the convex portion is a surface for molding the inner surface of the side wall 22 </ b> B of the groove portion 22.

  The first core 54 is accommodated in a vertical hole 58 formed in the lower surface 52 </ b> A of the lower mold 52. The first core 54 is connected to the first hydraulic cylinder 62 and can be moved in the vertical direction by the first hydraulic cylinder 62. As a result, the first core 54 can move between the retracted position accommodated in the vertical hole 58 and the advanced position moved upward from the retracted position and pressed against the lower surface 50 </ b> A of the upper mold 50. It is said that.

  On the other hand, the second core 56 is accommodated in a horizontal hole 60 formed in the side surface 52 </ b> B of the lower mold 52. The second core 56 is connected to the second hydraulic cylinder 64 and is movable in the left-right direction by the second hydraulic cylinder 64. As a result, the second core 56 is retracted into the horizontal hole 60 and moved forward from the retracted position to the right in the figure and is pushed against the left side surface 54A of the first core 54. It is possible to move between.

  First, when molding the door trim base material 24, as shown in FIG. 5, the first core 54 is advanced from the retracted position to the advanced position, and the first core 54 is pressed against the lower surface 50A of the upper mold 50. Next, the second core 56 is advanced from the retracted position to the advanced position, and the second core 56 is pressed against the first core 54 against the left side surface 54A. As a result, a first molding space S <b> 1 is formed on the left side of the first core 54. Then, by injecting the first resin from a first gate (not shown) arranged in communication with the first molding space S1, the first resin is introduced into the first molding space S1, as shown in FIG. Fill. When the first resin cools and hardens, the door trim base material 24 is formed.

  Next, when the second core 56 is retracted from the advanced position to the retracted position, a die-cut hole 66 for the second core 56 is formed in the door trim base 24. At this time, since the second core 56 has a tapered shape that tapers toward the tip, the second core 56 and the door trim base material 24 are not moved by simply retracting the second core 56 slightly. The second core 56 can be easily pulled out.

  When the first core 54 is retracted from the advanced position to the retracted position following the second core 56, a space 68 disposed on the right side of the door trim base 24 and the space 68 are communicated as shown in FIG. A second molding space S <b> 2 is formed that includes the punched hole 66. Then, from a second gate (not shown) arranged in communication with the second molding space S2, a second resin made of a material different from or different from the first resin in color is injected. Thus, as shown in FIG. 8, the second molding space S2 is filled with the second resin. When the second resin cools and hardens, the two-color molded article 11 in which the door trim base material 24 and the ornament base material 28 are two-color molded in the groove portion 22 is obtained. Although a slight gap is formed between the tip of the second core 56 and the opening edge of the horizontal hole 60, the shape of the tip of the second core 56 is such that the second resin does not enter the gap. Is set.

  Next, both the upper and lower molds 50 and 52 are opened in the vertical direction, and the two-color molded product 11 in which the door trim base material 24 and the ornament base material 28 are integrally formed in the groove portion 22 is removed as shown in FIG. To do. The two-color molded article 11 formed in this way is not strongly bonded at the interface 36, but the retaining portion 38 of the ornament base material 28 is fitted and fitted into the retaining recess 42 of the door trim base material 24. Therefore, even when bending stress is applied to both base materials 24 and 28 and stress concentrates on the groove portion 22, both base materials 24 and 28 are not broken at the boundary 34, and both base portions are not formed at the groove portion 22. The materials 24 and 28 can be firmly bonded.

  As described above, in this embodiment, although the groove portion 22 is formed at the boundary 34 between the door trim base material 24 and the ornament base material 28, the retaining portion 38 and the retaining recess portion 42 are formed in the groove portion 22, and these are firmly joined. Therefore, the two-color molded product 11 can be prevented from breaking in the groove portion 22. Further, since the retaining recess 42 is formed in a groove shape, the mold punching hole 66 can be tapered so as to go to the tip, and the second core 56 can be easily punched out.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) Although the groove portion 22 is formed at the boundary 34 between the door trim main body 12 and the ornament 14 in the above embodiment, according to the present invention, for example, when the door trim base material is composed of the main base material and the upper base material, the main base You may form a groove part in the boundary of a material and an upper base material.

  (2) In the above embodiment, although the two-color molded product 11 formed by two-color molding of the door trim base material 24 and the ornament base material 28 is used, according to the present invention, three or more types of base materials having different materials or the same material are used. It is good also as a multi-color molded product formed by multi-color molding of three or more kinds of substrates having different colors.

  (3) Although the retaining portion 38 is formed in the die punching hole 66 of the second core 56 in the above-described embodiment, according to the present invention, when the three cores are three or more types of multicolor molded products, the second core The retaining portion may be formed in a die punching hole different from the 56 die punching holes 66.

  (4) Although the skin materials 26 and 30 are attached to both the door trim base material 24 and the ornament base material 28 in the above embodiment, the skin material is attached only to one of the base materials according to the present invention. May be.

  (5) In the above embodiment, although the door trim base material 24 and the ornament base material 28 are molded resin-exposed products, according to the present invention, both skin materials 26 are provided on the surfaces of the base materials 24 and 28 as shown in FIG. , 30 may be used. Specifically, the door trim main body 12 includes a door trim base material 24 and a door trim skin material 26 attached to the surface of the door trim base material 24. On the other hand, the ornament 14 includes an ornament base material 28 and an ornament skin material 30 attached to the surface of the ornament base material 28. The overlapping portions of the end portions of both skin materials 26 and 30 are sewn together by a sewing thread 32 and joined together. The overlapping portion (sewing margin portion) of both the skin materials 26 and 30 is inserted into the groove portion 22 and adhered to the door trim base material 24 and the ornament base material 28 via, for example, hot melt tape (not shown). Has been.

11 ... Two-color molded product 24 ... Door trim base material (first molded product)
28 ... Ornament base material (second molded product)
34 ... boundary 38 ... retaining portion 42 ... retaining recess 50A ... lower surface of upper die (other side molding surface)
52A: Lower surface of the lower mold (one side molding surface)
54 ... 1st core 54A ... Left side (side surface) of 1st core
56 ... 2nd core 66 ... Die-release hole S1 ... 1st shaping | molding space S2 ... 2nd shaping | molding space

Claims (1)

A first molded article and a second molded article made of a different material or the same kind of material and having a different color, and a boundary between the first molded article and the second molded article. A method for producing a multi-color molded article having a configuration in which a groove is formed and the boundary is arranged at the bottom of the groove ,
A space formed between the concave portion and the convex portion by injecting resin between a lower mold having a concave portion recessed downward and an upper die having a convex portion entering the concave portion of the lower mold. Forming the groove corresponding to
A molding surface for molding the inner surface of the bottom of the groove portion, and a tip surface of the first core that moves vertically from the concave bottom surface of the concave portion of the lower mold to the convex tip surface of the convex portion of the upper mold And the space between the convex tip end surface of the upper mold and the concave bottom surface of the lower mold in the horizontal direction from the concave side surface of the concave part of the lower mold to the side surface of the first core. By pressing the front end surface of the moving second core , it is a space for molding the first molded product, and is surrounded by the upper mold, the lower mold, and the first core. Forming a first molding space in which the second core partially enters , and injecting resin into the first molding space to mold the first molded product; and
A second molding step in which a second molding space is formed by punching out both the first core and the second core, and the second molded product is molded by injecting resin into the second molding space. And
The second molding space is configured to include a die-cutting hole formed by die-cutting the second core from the inside of the first molded product. A method for producing a multicolor molded product, characterized in that the inner diameter increases toward the back along the die-cutting direction of the second core and has a groove shape.

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