JPH03159715A - Manufacture of composite object - Google Patents

Abstract

PURPOSE:To prevent burrs from occurring, while a molded body is molded integrally with sealing material firmly by a method in which in the manufacture of the composite object made of a plastic molded object and elastic sealing material, a groove is molded on a sealing face, and the groove is made into a reverse taper-construction by pushing the edge part of the sealing face by the clamping force of a secondary mold, and then sealing material is poured thereinto. CONSTITUTION:A cavity 3 is formed with together a cavity mold 1 and a primary core mold 2, and the plastic molded body 4 in which a groove 6 is provided on its sealing face 5, is molded by injecting plastic material. In the state where the molded body 4 is left in the cavity 1, the mold is opened, and the primary core mold 2 is replaced by a secondary core mold 7, and then the mold is clamped. The inner wall 7a of the secondary core mold 7 is caused to taper to the depth direction of a cavity 8, and the mold clamping is achieved, while the inner wall 7a is brought in contact with the edge part of the sealing face 5 in mold clamping. The groove 6 is made into a reverse taper-construction by being pushed inside. Next, sealing material is poured into the cavity 8, and elastic sealing material is molded on the sealing face 5.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a composite article in which a plastic molded body as a primary molded product and an elastic sealing material as a secondary molded product are integrated. In particular, the primary molded product and the secondary molded product are prevented from peeling and are firmly integrated, and the elastic sealing material is prevented from forming, and it is also applicable to small molded products. The present invention relates to a method for manufacturing a composite article that does not cause deformation or decrease in structural strength.

The above-mentioned composite products include automobile-related resin parts such as cylinder head covers, timing belt covers, radiator cores, headlamp housings, and tail lamp covers, electrical component parts such as wire harnesses, waterproof walls, and inhibitor switches, and artificial dialysis machines. , medical equipment such as milk bottles, daily necessities such as lunch boxes and various containers, waterproof radios,
Examples include electrical and electronic components such as waterproof speakers, rotor trimmers, and floppy housings, and instrumentation products such as water meter covers.

[Conventional technology]

Conventionally, as a method for integrally molding a plastic molded body as a primary molded product and an elastic sealing material as a secondary molded product, a primary tL-shaped product having a groove on the sealing surface is molded, and this primary molding While the product is still soft with residual heat, a secondary forming mold having push-in protrusions is pressed onto the sealing surface, and both sides of the groove are constricted by the protrusions to transform it into an inverted tapered shape. A method is known in which a secondary molded seal material is injected and hardened into a cavity of a secondary mold, and a secondary molded product is molded on the sealing surface.

According to this method, since a reverse tapered groove is formed on the sealing surface, the secondary molded product is firmly gripped and firmly integrated with the primary molded product, and the edge of the sealing surface is Since it bites into the mold, it prevents the occurrence of flakes.

[Problem that the invention seeks to solve]

However, the above-mentioned known technology requires a push-in space on both sides of the groove formed on the sealing surface, and therefore the width of the sealing surface must be wide to some extent, so it cannot be applied to small tL-shaped products. In addition, the load of the push-in protrusion causes deformation of the primary molded product, and furthermore, wedge-shaped depressions (notches) are formed on both sides of the groove, resulting in a decrease in structural strength.

Therefore, the purpose of the present invention is to prevent the primary molded product and the secondary molded product from peeling off and to firmly integrate them, and to prevent the occurrence of cracks in the elastic sealing material, and also to be applicable to small molded products. The object of the present invention is to provide a method for manufacturing a composite article that does not cause deformation of the primary molded article or decrease in structural strength, and that improves the drawbacks of the above-mentioned known techniques.

[Means for solving problems]

In order to achieve the above-mentioned object, according to the present invention, after clamping a secondary mold on the sealing surface of a plastic molded body as a primary molded product, a secondary mold is placed in the cavity of the mold. A groove is formed on the sealing surface to produce a composite article in which the plastic molded body and the elastic sealing material are integrated by pouring the sealing material and molding the elastic sealing material as a secondary molded product on the sealing surface. shape, and this groove is pressed inward from the edge of the sealing surface using the clamping force of the secondary molding die, thereby making the opening width of the groove smaller than the bottom width and reversing it. It is characterized in that it has a tapered structure, and then a secondary molded sealing material is poured into the cavity.

Hereinafter, the present invention will be explained in detail using the accompanying drawings.

FIG. 1 is a cross-sectional view of a mold for forming a primary molded product, in which a cavity mold 1 and a primary mold core mold 2 are combined to form a cavity 3.
A liquid plastic material is injected into this cavity 3 to form a plastic molded body 4 as a primary molded product.
to form. A groove 6 is provided on the sealing surface 5 of the plastic molded body 4. After the primary molding is completed, the mold is opened with the plastic molded body 4 remaining in the cavity mold 1, and then the primary core mold 2 is rotated or moved as shown in FIG. is replaced with the secondary molding core mold 7, and the mold is clamped in the direction of the bold line arrow.

The inner wall 7a of the secondary forming core mold 7 is tapered in the depth direction of the cavity 8, so that when the mold is clamped in the direction of the thick arrow, the inner wall 7a and the edge portion of the sealing surface 5
. is smaller than the bottom width l1, and the groove 6 has an inverted tapered structure.

Next, as shown in the third figure, a secondary molded sealing material is poured into the cavity 8, and an elastic sealing material 12 as a secondary molded product is formed on the sealing surface 5 of the glass stick body 4 as a primary molded product. . The cavity 8 of the secondary molding core mold 7 may be round or round depending on the shape of the required elastic sealing material l2.
The sealing surface 5 may be of any shape, including a square shape, a shape with a lip, or a shape in which the thickness is partially changed, and the sealing surface 5 may also have a three-dimensional structure in addition to a flat surface. do not have.

Next, by opening the mold and taking out the product, it is possible to continuously and rapidly mass-produce a strong composite article in which the primary molded product and the secondary molded product are firmly integrated, and there is no generation of flaking. .

As the primary molding resin material used in the present invention, any material can be used as long as it can form a structural member by injection molding. Specific examples include polypropylene, ABS, DBTSPA-6, PA-66, PET,
Examples include thermoplastic resins such as PC and PMMA, and thermosetting resins such as alkyd, urethane, melamine, epoxy, phenol, and UP.

The secondary molding resin material may be any material that can be molded into an elastic body by injection molding, as described above.
Specific examples include thermoplastic elastomers such as olefin-based, polyvinyl chloride-based urethane-based, and polyester-based thermosetting liquid elastomers such as silicone, urethane, polybutadiene, and polyester-based elastomers.

FIG. 5 is a perspective view of a waterproof case manufactured by the method of the present invention. The elastic sealing material 12 can be molded over the entire sealing surface even in small parts with a narrow sealing surface. If this width is 0.5 mark or more, preferably 1 mm or more,
Can be molded. The conventional push-in protrusion method requires at least 3 mm, preferably at least 5+nn+. The molding conditions were as follows: PA-630% GF-containing resin was used as the primary resin;
The resin melted at °C is first molded at a mold temperature of 120 °C and a cooling time of 20 seconds, the mold is opened, the mold is replaced, the secondary mold is clamped, and the secondary injection resin is made into a two-component thermosetting resin. Liquid silicone rubber "Three Bond 1270J" is used, and after mixing with a screw at room temperature, it is injected into a mold and the mold is opened after curing time of 15 seconds to obtain a composite molded product.Silicone resin is originally a resin for ordinary injection molding. However, the waterproof case shown in FIG. 4, which was molded according to the present invention, had no occurrence of any flakes and had a high degree of precision.

Next, PP talc-containing resin was used as the primary resin, and 210
After melting at 170°C and first shaping with a mold at room temperature for 15 seconds, the mold was moved, and PVC thermoplastic elastomer was used as the secondary molding resin, melting at 170°C and cooling time 1.
Secondary molding was performed in 5 seconds, and a waterproof case lid as shown in FIG. 6 was manufactured.

In the present invention, the groove 6 does not necessarily need to be crushed from both sides, and when molding on a thin flat plate-shaped primary molded product (plastic molded product main body) 4, the edge portion 9 on one side is not necessarily pressed. Only the inner wall 7a of the secondary molding core mold 7 is pressed. FIG. 4(b) is a cross-sectional view of the mold in which the elastic sealing material 12 is molded on the sealing surface 5 of FIG. 4(a).
The composite article molded by this mold is the lid of the waterproof case shown in FIG.

[Effect]

According to the above-mentioned invention, a groove is formed on the sealing surface, and this groove is pressed inward from the edge of the sealing surface by a secondary molding die using mold clamping force to form an inverted taber structure. Since the opening width of the groove is smaller than the width of the bottom surface, the secondary molded product will not fall out of the groove on the sealing surface of the secondary molded product. They are strongly integrated even when combined.

Furthermore, when the secondary forming core mold is clamped, the edges 9, 9 of the sealing surface 5 dig in along the inner wall 7a of the cavity 8, so the secondary Ii with good fluidity! Even when a material for type 2 is used, generation of flash is prevented.

In addition, when creating a groove with an inverted tapered structure, this is done by pressing inward from the edge of the sealing surface using the clamping force of the secondary mold. This is different from the method of squeezing and constricting the material, so no pressing space is required, so the secondary molded product can be molded over the entire sealing surface, and even parts with a narrow sealing surface can be molded, and the crushing load is small. Since there is no deformation of the primary molded product, and since no notches are formed due to push-in protrusions, there is no reduction in the structural strength of the product.

Furthermore, according to the method of the present invention, the main body of the plastic molded product is formed into a primary 15!2 shape and can be subsequently molded in a series of operations without removing it from the mold, so there are problems such as variations in molding accuracy caused by shrinkage. Highly accurate mass-produced products can be obtained.

〔Effect of the invention〕

According to the present invention described above, even if the primary molding resin and the secondary molding resin do not have adhesive properties, they can be automatically replaced by using a normal double injection mold replacement mechanism without any special operation. By creating a reverse taper structure, it is possible to manufacture composite molded products in which the plastic molded body and the elastic sealing material are firmly integrated, and at the same time prevent the occurrence of flakes, so there is no need for post-processing, and the quality is stable and accurate. Composite molded products with high efficiencies can be produced in large quantities at low cost. Furthermore, when creating the reverse tapered structure of the grooves, a product with no problems in terms of strength or functionality can be obtained without applying excessive load or deformation to the primary molded product. moreover,
Due to the design, the elastic sealing material can be molded to fill the entire sealing surface, so there are fewer restrictions on product design, allowing for freedom in designing, and a wide range of applications.

[Brief explanation of the drawing]

FIG. Figures 4(a) and 4(b) show a cross-sectional view of the state in which the secondary molding material is poured into the cavity.
) shows a process diagram for explaining another method of the present invention,
5 and 6 each show a perspective view of a composite article produced by the method of the invention. l... Cavity mold, 2... Primary molding core mold, 3... Cavity, 4... Plastic molded product body, 5... Seal surface,
6... Groove, 7... Secondary forming core mold, 8... Cavity, 9... Edge portion, 10... Opening width, 11... Bottom width, l2... Elastic seal Material.

Claims (1)

[Claims] After clamping a secondary molding mold onto the sealing surface of the plastic molding body as a primary molded product, a secondary molding sealing material is poured into the cavity of the mold and is placed on the sealing surface as a secondary molded product. When molding the elastic sealing material and manufacturing a composite article in which the plastic molded body and the elastic sealing material are integrated, a groove is formed on the sealing surface, and this groove is inserted into the secondary molding mold. The mold clamping force is used to press inward from the edge of the sealing surface, thereby making the opening width of the groove smaller than the bottom width to create a reverse tapered structure, and then pouring the secondary molded sealing material into the cavity. A method for manufacturing a composite article characterized by: