JP3114037B2 - Outsert molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rigid substrate having a through hole, wherein a part of a synthetic resin functional portion is fixed through the through hole so that the functional portion is integrally connected to the substrate surface. To an outsert molding method.

[0002]

2. Description of the Related Art An outsert molded product has a structure in which a functional component is fixed by using a through hole provided in a substrate. Easy to receive. The functional part is often required to have slidability, in which case a synthetic resin containing no filling material is used, and a relatively high molecular weight with excellent mechanical strength against creep rupture due to the internal residual strain. This is supported by selecting a higher grade. In addition, the molded product must be able to cope with lightness, thinness, and miniaturization. In this case, in addition to strength, rigidity, wear resistance and chemical resistance, fluidity is required,
If the fluidity is pursued, a grade having a low molecular weight must be selected, and the creep rupture strength is lowered. As described above, if the emphasis is placed on the fluidity, the creep rupture strength is reduced, and if the creep rupture strength is emphasized, the fluidity is deteriorated. Therefore, in the past, for example,
As described in Japanese Patent Publication No. 379, an attempt has been made to provide a gap for absorbing stress on the resin shrinkage side of the fixed portion to cope with creep rupture from a structural aspect.

[0003]

Conventionally, creep destruction has been avoided from a structural viewpoint such as providing a stress absorbing gap on the resin shrinkage side of the fixed portion. Advanced technology is required for design and molding process programs. On the other hand, if a solution in terms of material technology becomes possible, such a technology becomes unnecessary. Now, in the prior art, a filler-free resin composition is desired to improve the slidability, and the filler-free resin composition is effective against creep rupture if the molecular weight increases. On the other hand, it is based on the basic theory that fluidity tends to deteriorate, and if either property can be solved without depending on the molecular weight, both can be achieved. Then, the inventor challenged to achieve both strength and fluidity against creep rupture and ensure slidability from the viewpoint of the resin composition.

[0004]

SUMMARY OF THE INVENTION The present invention is an outsert molding method which solves the above problems from the viewpoint of a resin composition. The method comprises forming a functional part in a molding die in which a substrate is set. A thermoplastic resin filled with 1 to 5% by weight of at least one filler selected from the group consisting of fibrous fillers, granular fillers, and plate-like fillers as a resin composition for use is flow-solidified and solidified. And a resin-made functional unit. Preferred specific examples of the filler include glass fibers which are fibrous fillers,
Examples include potassium titanate fiber, carbon fiber, titanium oxide fiber, glass beads as a particulate filler, and glass flakes as a plate-like filler. As the thermoplastic resin, it is preferable to select and use a polyacetal resin having a melt index of 10 or more or a polybutylene terephthalate resin having a melt index of 10 or more. Further, as the resin composition for forming a functional part, a compounded lubricant with a filler is preferable, and as an example of the lubricant,
Mineral oils, higher fatty acids, fatty acid esters, fatty acid amides, fatty acid metal salts, silicone oils, polyethylene waxes, fluorine resins, and the like.

[0005]

By specifying the filling amount of the filler in the resin composition for forming a functional part, or more preferably, by specifying the resin to be used and its melt index, the interaction between them is good and the flowability is high. It was confirmed that the mechanical strength was exhibited, and a solution in terms of material technology became feasible.

[0006]

EXAMPLES The effects of the present invention will be described below with reference to examples. Example 1 Melt index (190 ° C., 2160 g) is 14
An acetal copolymer (hereinafter referred to as POM), which is a polyacetal resin, was filled with 3% by weight of a fibrous filler made of glass fiber to obtain a resin composition. This resin composition was injection-molded by a usual method on a steel plate provided with six resin inlet holes to obtain a test piece of an outsert molded product. The obtained test piece is shown in FIG. The test piece has a structure in which the resin sandwiches the steel plate in a substantially U-shape at two locations of a hollow rectangular steel plate, and the length, width, and thickness of the steel plate are 100 mm, 34 mm, 1.2 mm, respectively. Vertical of hollow part,
The horizontal dimensions were 80 mm and 14 mm, respectively, and the vertical, horizontal and thickness dimensions of the resin were 70 mm, 7.5 mm and 4.2 mm, respectively. Examples 2 to 7 A test piece of an outsert molded product was prepared in the same manner as in Example 1 except that the melt index of the POM resin and the type and amount of the filler to be filled were appropriately changed as shown in Table 1. I got Example 8 A resin composition was prepared in the same manner as in Example 2 except that glycerin monostearate was added at 2% by weight as a lubricant.
A test piece of an outsert molded product was obtained. Example 9 The resin was melt-indexed (235 ° C., 2160
g) A test piece of an outsert molded product was obtained in the same manner as in Example 1 except that the polybutylene terephthalate (PBT) resin having 13 was used. Examples 10 to 12 The melt index of the PBT resin and the type and amount of the filler to be filled were changed as shown in Table 1, except that the melt index and the amount of the fillers of Examples 10 to 12 were changed in the same manner as in Example 9. A test piece of a molded product was obtained.

On the other hand, regarding the resin composition from which the filler is omitted,
As a comparative example, a test piece similar to the above was molded. Comparative Example 1 A POM resin having a melt index of 9 was fitted and formed on a steel sheet in the same manner as in Example 1 without filling a filler, to obtain a test piece of an outsert molded product. Comparative Example 2 A test piece of an outsert molded product was obtained in the same manner as in Example 1 except that the filler was not filled. Comparative Example 3 An outsert molded product test piece was obtained in the same manner as in Example 2 except that the filler was not filled. Comparative Example 4 A test piece of an outsert molded product was obtained in the same manner as in Examples 3 to 5, except that the filler was not filled. Comparative Example 5 An outsert molded product test piece was obtained in the same manner as in Example 8 except that no filler was filled. Comparative Example 6 An outsert molded product test piece was obtained in the same manner as in Example 9 except that no filler was filled. Comparative Example 7 A test piece of an outsert molded product was obtained in the same manner as in Examples 10 to 12 except that the filler was not filled.

The contents, molding fluidity, sliding characteristics, and creep rupture life characteristics of each resin composition of the test piece of each example were measured, and the evaluation results are shown in Table 1. Table 2 shows the results of the comparative examples. The molding fluidity was evaluated based on the flow distance when injection was performed at a thickness of 2 mm and a pressure of 1000 kgf / cm ² . In addition, the sliding characteristics, for POM resin and steel,
The dynamic friction coefficient and the amount of friction and wear were evaluated. All measurements were carried out by the thrust method. The kinetic friction coefficient for POM and the amount of friction and wear were 0.6 kgf / cm ^{2 at} a surface pressure of 15 cm / sec and the kinetic friction coefficient and the amount of friction and wear for steel were 10
The measurement was performed under the conditions of kgf / cm ² and a speed of 30 cm / sec. For the amount of friction and wear, the total value of both materials was calculated. Regarding the creep rupture strength, the average number of days until cracks occurred when five outsert molded articles were heat-aged at 120 ° C. was determined, and the creep rupture life was evaluated.

[0009]

[Table 1]

[0010]

[Table 2]

As is apparent from these results, the resin compositions of the examples have better fluidity and better creep rupture life characteristics than conventional resin compositions. It also has excellent sliding properties.
The effect when 5% was filled was remarkable, and it was also found that the sliding characteristics were remarkably improved in the example in which a lubricant was further added. These results were obtained by using a grade with a high melt index to ensure good fluidity as per the theory, and to enhance the creep rupture strength by the filled filler, It is presumed that the sliding characteristics could be improved by specifying the filling rate of. Therefore, if the resin composition of the present invention is used,
Outsert molding of fine or thin functional parts and sub-runners can be performed without any problem, and the characteristics of the molded product are sufficiently ensured. It is perfect for making machine parts with precise and complex shapes.

[0012]

According to the present invention, it is possible to select a thermoplastic resin having a melt index of 10 or more and to solve the problem from the material technology such as controlling the filling amount of the filler. No, it is easy to implement.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a test piece.

FIG. 2 is a sectional view of the test piece taken along line AA.

[Explanation of symbols]

1. Steel plate, 2. Resin composition, 3. Hall, 4.
Resin inlet.

Continuation of the front page (56) References JP-A-5-28851 (JP, A) JP-A-2-153712 (JP, A) JP-A-6-254905 (JP, A) JP-A-63-120617 (JP) JP-A-55-49240 (JP, A) JP-A-3-285945 (JP, A) JP-A-64-60651 (JP, A) JP-A-63-49414 (JP, A) 51-117755 (JP, A) JP-A-2-36916 (JP, A) JP-A-63-243162 (JP, A) JP-A-63-3055 (JP, A) JP-A-2-150322 (JP, A) A) JP-A-2-192920 (JP, A) JP-A-3-110903 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/24

Claims (5)

(57) [Claims] In an outsert molding method in which a part of a synthetic resin functional part is fixedly penetrated through a through hole formed in a hard substrate, the functional part is integrally connected to a substrate surface. Into the set mold, at least one or more fillers selected from the group consisting of fibrous fillers, granular fillers, and plate-like fillers as a resin composition for forming a functional part are filled in an amount of 1 to 5% by weight in total. An outsert molding method characterized by flowing in and solidifying a thermoplastic resin. 2. The method according to claim 1, wherein the filler is at least one selected from glass fibers, potassium titanate fibers, carbon fibers, titanium oxide fibers, glass beads, and glass flakes. The described outsert molding method. 3. The outsert molding method according to claim 1, wherein a polyacetal resin having a melt index of 10 or more is selectively used as the thermoplastic resin. 4. The outsert molding method according to claim 1, wherein a polybutylene terephthalate resin having a melt index of 10 or more is used as the thermoplastic resin. 5. The outsert molding method according to claim 1, wherein the resin composition further contains a lubricant.