JPH10329172A - Multilayer dichroic molding and dichroic mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent warp deforming of a multilayer wall due to a difference of shrinkage factors of primary and secondary plastic materials in a multilayer dichroic molding. SOLUTION: This molding comprises recesses 3, 4 partitioned by a partition wall 5 on front and rear surfaces of a surface wall of a molding wall 1. The recesses 3, 4 are filled with forming plastic materials, and a front wall 7 and rear wall 8 of the same shape and size are formed. And, a stress generated between the walls 7 and 5 is brought into coincidence with a stress generated between the walls 8 and 5 to cancel both the stresses to one another.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-color molded product in which different kinds of plastic materials are integrally molded in a multilayer shape, and a two-color molding die for molding such a two-color molded product. Here, the two-color molding is synonymous with the two-stage molding, and it is not necessarily limited that each molded layer has a different color.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 5-237873 discloses a two-color molded product in which a different plastic material is molded twice and each plastic material is integrally molded in a multilayer shape.
Here, for example, the primary molding layer is formed of a colored plastic material, and the secondary molding layer is formed of a transparent plastic material.

[0003]

In a two-color molded product obtained by integrally molding different plastic materials in a multilayer shape, a difference in molding shrinkage (hereinafter simply referred to as shrinkage) inherent to each plastic material becomes a problem. . For example, depending on the difference in the shrinkage rate between the primary and secondary molding layers, the multilayer wall portion may be warped or may have a gap between adjacent peripheral surfaces of the molding layers. Even when a clear warp deformation or the like cannot be confirmed visually, internal stress may remain in the molded layer.

An object of the present invention is to eliminate the occurrence of molding defects caused by the above-described differences in the shrinkage rates of different plastic materials, and in particular, the occurrence of warpage deformation, which often causes problems in appearance or use, and provides a multilayered plastic material. It is an object of the present invention to improve the yield of two-color molded products and to improve the productivity of a multilayer two-color molded product as a whole. Another object of the present invention is to provide a two-color molding die suitable for molding the above-described two-color molded product.

[0005]

The two-color molded article of the present invention is:
As shown in FIG. 1, a two-color molded product in which a primary molded wall 1 and a secondary molded wall 2 are integrally molded in a multilayer shape using a different plastic material. Indentations 3 and 4 of the same shape and size are provided in a part of the face wall of the primary molded wall 1 so as to face each other. An opening 6 is provided. The secondary molding wall 2 including the front wall 7 and the back wall 8 is formed flush with the front and back surfaces of the primary molding wall 1 by filling the double recesses 3 and 4 and the opening 6 with the secondary molding plastic material. . Thus, the difference between the molding shrinkage rates of the primary and secondary molding walls 1 and 2 is made uniform between the front side and the back side of the multilayer wall portion 10.

[0006] The two-color molding die of the present invention has a primary molding wall 1 in which a partition wall 5 is formed on a part of a face wall as shown in FIG.
And a secondary molded wall 2 including a front wall 7 and a rear wall 8 of the same shape and the same size formed on the front and back of the partition wall 5, a two-color molded article in which the multilayer wall portion 10 is integrally molded. I do. There, Figure 3
As shown in (1), a primary molding space S1 for forming the primary molding wall 1 is formed between the joining surfaces of the fixed mold 12 and the movable mold 13. For each of the fixed mold 12 and the movable mold 13,
First and second slide cores 14 and 15 that protrude into the primary molding space S1 and occupy the secondary molding space S2 for forming the front wall 7 and the back wall 8 are provided in opposition. A vertical core portion 18 for vertically forming a vertical portion 9 for connecting the front wall 7 and the back wall 8 integrally with each other by vertically passing through the forming space of the partition wall 5 in the thickness direction,
It is provided on one of the slide cores 14 and 15.

Specifically, a second gate 17 for injecting a secondary molded plastic material is provided inside the slide core 14 on the fixed mold 12 side. Alternatively, as shown in FIG. 5, a third slide core 20 that is independently reciprocally slid is provided inside the slide core 15 on the movable mold 13 side, and a vertical core is provided at a protruding end of the third slide core 20. The part 18 can be formed.

[0008]

The primary and secondary partitions 5 are sandwiched therebetween, and the front and rear walls 7 and 8 of the same shape and size are secondary-formed on the front and back, and shrinkage on the front side and the rear side of the multilayer wall portion 10 is achieved. Since the difference between the rates is made uniform, the stress generated between the front wall 7 and the partition wall 5 and the stress generated between the back wall 8 and the partition wall 5 can be made the same. In other words, the deformation stresses on the front and back sides are antagonized to cancel each other out, thereby preventing the multilayer wall portion 10 from being warped.

[0009]

1 and 2 show an embodiment of a two-color molded product according to the present invention. In the figure, the two-color molded product is composed of a primary molded wall 1 formed in a rectangular shape that is horizontally long on the left and right, and a secondary molded wall 2 formed by lamination on the front and back of the primary molded wall 1. Primary molded wall 1
The secondary molding wall 2 is molded from a different plastic material.

On the front and back of the primary molded wall 1, recesses 3.4 of the same shape and the same size are provided facing each other to form the secondary molded wall 2, and a partition wall for dividing the recesses 3.4 is formed. A circular port 6 for communicating the two recesses 3 and 4 with each other is provided at one central portion of 5. The double recesses 3 and 4 are formed in a rectangular shape when viewed from the plane or the bottom side in a state of crossing between the long sides of the primary molded wall 1 back and forth. The depths of the recesses 3 and 4 are the same, and are set slightly larger than the thickness of the partition wall 5.

The secondary molding wall 2 is formed by filling each of the recesses 3 and 4 with a secondary molding plastic material. The secondary molded wall 2 includes a front wall 7 and a back wall 8 that fill the recesses 3 and 4, and a vertical passage portion 9 that fills the inside of the opening 6 and integrally connects the front wall 7 and the back wall 8. Consists of The front wall 7 and the back wall 8 are formed so as to be flush with the surface and the back surface of the thick portion of the primary molded wall 1. The front wall 7 and the back wall 8 which are formed secondarily, and the partition wall 5 sandwiched between the both walls 7.8,
A sandwich-like multilayer wall 10 is formed.

As described above, if the front wall 7 and the rear wall 8 of the same shape and the same size are formed on the front and back of the multi-layer wall portion 10, it occurs between the front wall 7 and the partition wall 5. The stress based on the difference in the shrinkage and the stress based on the difference in the shrinkage generated between the back wall 8 and the partition wall 5 can be antagonized and canceled. As a result, it is possible to prevent the multilayer wall portion 10 from warping and deforming toward the front surface or the back surface.

Next, a two-color molding die for molding the above-described two-color molded article will be described. In FIG. 3, the two-color molding die has an upper fixed die 12 and a lower movable die 13 which slides toward and away from the fixed die 12. A primary molding space S1 for forming the primary molding wall 1 is formed between the joining surfaces of the first and second joining surfaces. First and second slide cores 14 and 15 occupying a secondary molding space S2 for forming the front wall 7 and the back wall 8 are provided in the fixed mold 12 and the movable mold 13, respectively. A first gate 16 for injecting the primary molding plastic material into the primary molding space S1 is provided near one side of the fixed mold 12. The second gate 17 for injecting the secondary molded plastic material is provided inside the first slide core 14.

The slide cores 14 and 15 have an advanced position where each core end projects into the primary molding space S1;
From the primary molding space S1, the fixed mold 12 and the movable mold 13
Can slide back and forth over the respective molding positions retracting into the inside of the. At the core end of the first slide core 14,
A longitudinal core portion 18 for forming the longitudinal portion 9 is formed so as to protrude. At the advanced position of the first slide core 14,
The longitudinal core 18 contacts the core end of the second slide core 15.

The two-color molding die configured as described above is
As shown in FIG. 4A, the first and second slide cores 1
With the first and fourth gates 4 and 15 in the advanced position,
From 6, a plastic material is injected into the primary molding space S <b> 1 to mold the primary molding wall 1. Thereafter, as shown in FIG. 4B, the slide cores 14 and 15 are retracted to the molding position to open the secondary molding space S2, and a plastic material is injected from the second gate 17 into the secondary molding space S2. Then, the secondary formed wall 2 is formed. Finally, the movable mold 13 is opened to take out the molded product. In this embodiment, since the longitudinal core portion 18 is provided on the first slide core 14, the completed two-color molded product has the same shape as the longitudinal core portion 18 on the surface side of the front wall 7. Are formed.

FIG. 5 shows another embodiment of a two-color molding die.
Here, a third slide core 20 that is independently reciprocally slid is provided inside the second slide core 15, and a protruding end of the third slide core 20 is used as a vertical through core 18. This is different from the previous embodiment. When such a third slide core 20 is provided, it is possible to eliminate the emergence of a punched hole and to arbitrarily change the thickness dimension of the partition wall 5.

[0017]

According to the two-color molded product of the present invention, a front wall 7 and a back wall 8 of the same shape and the same size are formed on the front and back of the partition wall 5 formed by the primary molding. By generating an equal stress based on the difference in the shrinkage ratio on the back side and canceling out the opposing stresses, warpage of the multilayer wall portion 10 was prevented from occurring. Thus, in a multilayer two-color molded product, molding defects accompanied by warpage can be eliminated, and the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA in FIG.

FIG. 2 is a perspective view of a two-color molded product.

FIG. 3 is a sectional view of a two-color molding die.

FIG. 4 is a sectional view showing a molding procedure of a two-color molded article.

FIG. 5 is a sectional view showing another embodiment of a two-color molding die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary molded wall 2 Secondary molded wall 3.4 Indentation 5 Partition wall 6 Passageway 7 Front wall 8 Back wall 10 Multilayer wall

Claims (3)

[Claims] 1. A two-color molded product in which a primary molded wall 1 and a secondary molded wall 2 are integrally molded in a multilayered form using a different plastic material, and a part of a face wall of the primary molded wall 1 is Depressions 3.4 of the same shape and the same size are provided opposite to each other, and the partition wall 5 that separates both depressions 3.4 has front and rear depressions 3.4.
A through-hole 6 for communicating between the two is provided. The two-sided recesses 3 and 4 and the through-hole 6 are filled with a secondary molding plastic material to form a secondary molding wall 2 including a front wall 7 and a back wall 8.
It is formed flush with the front and back surfaces of the primary molded wall 1, and the difference in molding shrinkage between the primary and secondary molded walls 1 and 2 is uniform between the front side and the back side of the multilayer wall portion 10. A multi-layer, two-color molded product that has been formed. 2. A secondary molded wall including a primary molded wall 1 in which a partition wall 5 is formed in a part of a face wall, and a front wall 7 and a rear wall 8 of the same shape and the same size formed on the front and back of the partition wall 5. 2 and multi-layer wall 1
Numeral 0 is a two-color molding die for molding a two-color molded product integrally molded, and forms a primary molding wall 1 between the joining surfaces of the fixed die 12 and the movable die 13. Forming mold S1 is formed in each of the fixed mold 12 and the movable mold 13 so as to protrude into the primary molding space S1 to form the front wall 7 and the back wall 8. First and second slide cores 1 occupying S2
The vertical passages 4 and 15 are provided to face each other. The vertical passages for vertically forming the partition wall 5 in the thickness direction and forming the vertical connecting portion 9 for integrally connecting the front wall 7 and the back wall 8 are formed. A two-color molding die in which a core portion 18 is provided on one of the slide cores 14 and 15. 3. A second gate 1 for injecting a secondary molded plastic material into the slide core 14 on the fixed mold 12 side.
7 is provided. Inside the slide core 15 on the movable mold 13 side, a third slide core 20 which is independently reciprocally slid is provided. The two-color molding die according to claim 2, wherein the longitudinal core portion (18) is formed.