JPH03159716A - Manufacture of composite article - Google Patents

Abstract

PURPOSE:To mold integrally a composite article firmly and to prevent burrs from being generated by a method in which in the manufacture of the article integrally molded with a plastic molded article and elastic sealing member, the groove having a small protrusion on its edge is molded on a sealing face, and the protrusion is crushed by the mold-clamping force of a secondary mold, and after it has been bulged out on the side of an opening, sealing material is poured thereinto. CONSTITUTION:A cavity 3 is formed with together a cavity mold 1 and a core mold 2, and the molded body in which a groove 6 is provided on a sealing face 5, is molded by injecting plastic material. The cordlike small protrusions 6b are molded in the position a little more recessed to a sealing face 5 than the corner 6a of its edge along said groove. In the state where the molded body 4 is left in the cavity mold 1, the mold is opened. Next, when a primary core mold 2 is replaced by a secondary core mold 7, and the molds are clamped, the small protrusions 6b are crushed by the mold- clamping force and are squeezed out on the side of the opening 10 of the groove, and the width of the opening 10 is more narrowed than the width of a bottom face 11. Next, secondary sealing material is poured into a cavity 8, thereby molding an elastic sealing member 9 on the sealing face 5 of the molded body 4.

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, it is possible 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. The present invention relates to a method for manufacturing a composite article that does not cause deformation and also does not cause a decrease in structural strength.

The above-mentioned composite products include automobile-related resin parts such as cylinder head covers, timing belt power bars, radiator cores, headlamp housings, and tail lamp power bars, electrical component parts such as wire harnesses, waterproof walls, and inhibitor switches, and artificial dialysis. Medical equipment such as containers and chewing 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, floppy housings, and instrumentation products such as water meters and power bars.

[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 molded product with grooves on the sealing surface is molded, and this primary molded product is heated by residual heat. Then, while it is still soft, press a secondary molding mold having push-in protrusions onto the sealing surface, constricting both sides of the groove with the projections and deforming it into an inverted taber shape, and then press the secondary molding mold A method is known in which a secondary molded sealing material is injected and cured within the space of the sealing surface, and a secondary molded product is formed on the sealing surface.

According to this method, since an inverted 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 Because 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 molded 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 invention, after clamping a secondary circular mold on the sealing surface of the main body of a plastic molded product as a primary molded product, secondary molding is performed in the cavity of the mold. A sealing material is poured and an elastic sealing material is formed as a secondary molded product on the sealing surface to produce a composite article in which the plastic precept main body and the elastic sealing material are integrated. After forming a groove with a small protrusion on the edge and crushing the small protrusion using the clamping force of the secondary hollow mold to make it protrude beyond the corner of the edge toward the groove opening side,
The method is characterized in that 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 sectional view of a mold for forming a primary molded product, and the cavity 3 is formed by combining the cavity mold 1 and the primary mold core mold 2.
A liquid plastic material is injected into this cavity 3 to form a plastic precept 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. At least one edge of this groove 6, preferably both edges, has an edge corner 6 along the groove 6.
A string-shaped small protrusion 6b is formed at a location slightly deeper into the sealing surface 5 than a. This small protrusion 6b may be formed along the edge corner 6a as shown in the fourth figure. These small protrusions 6b may have a width and height of about 0.05 to 2 mm, preferably about 0.1 to 1 mm, and are preferably triangular in shape with an acute angle in cross section because they are easily crushed. After the first precept is completed, the plastic molded body 4 is placed in the cavity mold l.
The mold is opened in the direction of the arrow in FIG. 1 while leaving the . , tighten the mold in the direction of the arrow. Then, the small protrusion 6b is crushed by the clamping force of the secondary core mold 7 and protrudes beyond the edge corner 6a toward the opening 10 side of the groove 6, as shown in the third figure. 10 is narrower than the width of the bottom surface l1. This also applies to the case of the small protrusion 6b shown in the fourth figure.
The same is true as shown in FIG.

Next, as shown in FIGS. 3 and 6, a secondary hollow sealing material is poured into the cavity 8, and an elastic sealing material as a secondary molding is placed on the sealing surface 5 of the plastic trap body 4 as a primary molding. Mold 9. The cavity 8 of the secondary forming core mold 7 can be of any shape, such as round, square, with a lip, or with a partially changed thickness, depending on the shape of the elastic sealing material 9 required. Moreover, the sealing surface 5 may also have a three-dimensional three-dimensional structure in addition to being flat.

Next, when the secondary core mold 7 is moved in the direction of the arrows in Figures JJ3 and 6 to open the mold and take out the product, the primary molded product and the secondary molded product are firmly integrated. It is possible to mass-produce high-strength composite articles continuously and at high speed without the occurrence of spalling.

As the primary molding resin material used in the present invention, any material can be used as long as it can be formed into a structural member by injection molding. Specific examples include polypropylene, ABS, DBT, FA-6, PA-66, PET1
Examples include thermoplastic resins such as PC and PMMA, and thermosetting resins such as alkyphd, urea, melamine, epoxy, phenol, and UP.

The secondary molding resin material may be any material that can be shaped into an elastic body by skewering as described above.
Specifically, thermoplastic elastomers such as resin-based, polyvinyl chloride-based urethane-based, and polyester-based elastomers, and thermosetting liquid elastomers such as silicone, urethane, polybutadiene, and polyester-based elastomers are mentioned.

According to the present invention, the elastic sealing material 9 can be formed over the entire sealing surface even in a small component with a narrow sealing surface 5. This width is 0, . 5ma+ or more, preferably 1f
If it is more than 1, it is possible to be punished. The conventional push-in protrusion method requires three or more strokes, preferably five or more strokes.

Next, examples of the method of the present invention will be shown. The forming conditions were as follows: PA-630% GF-containing resin was used as the primary resin, the resin was melted at 280°C, the mold temperature was 120°C, the cooling time was 20 seconds, the mold was opened, and the mold was replaced. Clamp the rolled secondary mold, use two-component thermosetting liquid silicone rubber "Three Bond 1270J" as the secondary injection resin, mix it with a screw at room temperature, inject into the mold, and open the mold after curing time of 15 seconds. A composite molded product was obtained.Silicone resin has lower precision than normal injection molding resin, and it flows out as particles when the clearance is about the same as the normal parting surface.
The composite article according to the present invention had no occurrence of paris and had high precision.

Furthermore, using PP talc-containing resin as the primary molding resin, 21
After melting at 0°C and first forming with a mold at room temperature for 15 seconds of cooling, move the mold, use PVC thermoplastic elastomer as the secondary molding resin, melt at 170°C, and cool for 15 seconds. Secondary cutting was performed in seconds to produce a composite article according to the invention.

[Effect]

According to the above-mentioned invention, a groove having a small protrusion at the edge is formed on the sealing surface, and the small protrusion is crushed using the clamping force of the secondary round mold, so that the groove opening is closer to the corner of the edge. Since the width of the opening of the groove is smaller than the width of the bottom, the secondary molded product will not fall out of the groove on the sealing surface of the secondary molded product, and this will improve the adhesiveness. The combination of the plastic molded body and the elastic sealing material, which do not have any pores, can be firmly integrated, and even if a secondary sealing material with good fluidity is used, the occurrence of cracks can be prevented.

In addition, in the present invention, the width of the groove opening can be formed smaller than the width of the bottom surface by simply crushing the small protrusion formed on the sealing surface using the clamping force of the secondary mold. The push-in protrusions are used to crush both sides of the groove, and no push-in space is required as in the constricting process, so the secondary molded product can be formed over the entire sealing surface, and even parts with a narrow sealing surface can be shaped. Moreover, since there is no crushing load due to the push-in protrusions, the primary molded product will not be deformed, and since no notches are formed by the push-in protrusions, there will be 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 first shaped and can be subsequently formed in a series of imitations without removing it from the mold, which eliminates 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 above-described present invention, the width of the groove opening is automatically formed smaller than the width of the bottom surface by using a normal double injection mold replacement mechanism, and the width of the groove opening is automatically formed to be smaller than the width of the bottom surface. Even if the secondary molding resin lacks adhesive properties, it is possible to manufacture a composite molded product in which the plastic molded body and the elastic sealant are firmly integrated, and at the same time, the occurrence of flakes can be prevented, so there is no need for post-processing. Composite molded products with stable quality and high precision can be produced in large quantities at low cost. Further, when forming the narrow groove at the opening, no excessive load or deformation is applied to the primary molded product, and a product with no problems in terms of strength or functionality can be obtained. Furthermore, since the elastic sealing material can be shaped to fill the entire sealing surface, there are fewer restrictions on product design, allowing for freedom of design, and a wide range of applications.

[Brief explanation of the drawing]

Figures 1 and 4 each show a cross-sectional view of an example of a mold for forming a primary molded product, and Figures 2 and 5 each show a cross-sectional view of a specific example of a mold for forming a secondary molded product. 3 and 6 are cross-sectional views of the secondary forming material poured into the cavity formed by the mold clamping of FIGS. 2 and 5, respectively. ■... Yabi mold, 3... Cavity, 5... Seal surface, 6b... Small protrusion, 8... Yabby, 10... Opening, 2-... Primary molding core mold , 4...Plastic molded product body, 6...Groove, 6a...Edge corner, 7...Secondary molding core mold, 9...Elastic sealing material, 11...Bottom surface,

Claims (2)

[Claims] (1) After clamping the secondary mold on the sealing surface of the plastic molded body as the primary molded product, pour the secondary molding sealing material into the cavity of the mold and apply the secondary molding onto the sealing surface. When molding the elastic sealing material as a molded product and manufacturing a composite article in which the plastic molded body and the elastic sealing material are integrated, a groove having a small protrusion at the edge is formed on the sealing surface, and the small protrusion is formed on the sealing surface. The second molding sealing material is poured into the cavity after the protrusion is crushed using the mold clamping force of the second molding mold so as to protrude beyond the corner of the edge toward the groove opening side. A method for manufacturing a composite article. (2) The method according to claim 1, wherein the small protrusions are formed on both edges of the groove.