JPS63125552A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which is excellent in tensile characteristics, surface smoothness and processability and can give a clip cap excellent in insertion workability, and nonbreakability upon pulling, by mixing a PP resin with an ethylene/propylene rubber, a low-density linear PE resin and a silicone oil. CONSTITUTION:100pts.wt. in total of 50-70pts.wt. PP resin and 50-30pts.wt. ethylene/propylene rubber obtained, for example, by copolymerizing 60-70mol% ethylene with 40-30mol% propylene is mixed with 5-20pts.wt. low-density linear PE resin of a density of about 0.92 and 1-5pts.wt. silicone oil which is an organosilicon polymer comprising siloxane bonds.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a polypropylene resin composition, and more specifically, a polypropylene resin that provides a clip cap with good insertion workability and less tearing when removed. Regarding the composition. The present Voliv-O-pyrene resin composition is particularly used for clip caps for attaching side moldings.

[Prior Art] Normally, in order to improve the sealing performance of a side molding etc. that is attached to an automobile, a clip 3 of a side molding 4 is pressed and inserted into a clip cap 1 as shown in FIG. It will be installed. In this case, a considerable frictional force is generated between the clip 3 and the clip cap 1, so that the clip cap 1 made of a normal thermoplastic resin material is often torn when it is removed. Therefore, thermoplastic polyester resins called engineering plastics have conventionally been mainly used as materials for the clip caps.

[Problems to be Solved by the Invention] The above-mentioned conventional clip cap made of thermoplastic polyester resin has low surface smoothness, resulting in poor clip insertion workability, and this material is also expensive.

The present invention overcomes this drawback, and aims to provide a polypropylene resin composition that provides a clip cap that is easy to insert and prevents tearing when removed.

[Means for Solving the Problems] The polypropylene resin composition of the present invention contains 100 parts by weight in total of polypropylene resin and ethylene propylene rubber, 5 to 20 parts by weight of linear low density polyethylene resin, and silicone oil. The content of the polypropylene resin is 50 to 70 parts by weight, and the content of the ethylene propylene rubber is 30 to 50 parts by weight.

The above polypropylene resin is mainly produced by polymerizing propylene monomers using various known polymerization methods,
Known and commonly used polypropylene resins can be used.

The above ethylene propylene rubber usually has a 60 to
Ethylene propylene rubber (EPM) obtained by copolymerizing 70 mol% ethylene and 30 to 40 mol% propylene
) or EPDM to which a small amount of a third component (diene monomer) is added can be used. Usually, a non-conjugated diene such as ethylidenenorbornene, dicyclopentadiene, 1,4-hexadiene, etc. is used as the third component.

As this polymerization method, any known conventional method can be used.

The total amount of the polypropylene resin and ethylene propylene rubber is 100 parts by weight, of which the polypropylene resin is 50 to 70 parts by weight and the ethylene propylene rubber is 30 to 50 parts by weight. This total amount is 10
If the polypropylene resin is less than 50 parts by weight, the tensile strength will decrease and the cap will easily break when removed, and if the polypropylene resin exceeds 70 parts by weight, the clip cap will be damaged. This is not preferable because the hardness increases and the insertion workability deteriorates.

The density of the above linear low density polyethylene resin is approximately 0.92.
It is almost equivalent to conventional low-density polyethylene, but it has a linear structure with almost no long chain branches. It is currently produced by a liquid phase method or a gas phase method, both of which are produced by adding a small amount of 1-olefin, such as 1-hexene, to ethylene and polymerizing it. The blending amount of the linear low density polyethylene resin is 5 to 20 parts by weight when the am of the polypropylene resin and the ethylene propylene rubber is 100,111 parts. In this amount, it is possible to soften the material without lowering its physical properties such as tensile strength. If this blend [i] is less than 5 parts by weight, the effect of this addition will not be sufficient, and if it exceeds 20 parts by weight, the improvement in physical properties such as tensile strength will be less than desired, which is not preferred.

The silicone oil is an organic silicon polymer composed of siloxane bonds and is in the form of an oil. By adding this silicone oil, the surface smoothness of the clip cap can be increased. If the amount of silicone oil added is less than 11 parts by weight, the effect of adding silicone oil will not be sufficient, and if it exceeds 5 parts by weight, excessive silicone oil will bleed onto the surface of the clip cap, which is not preferred.

[Effects of the Invention] The polypropylene resin composition of the present invention has a total amount of polypropylene resin and ethylene propylene rubber of 100 parts by weight, and a linear low density polyethylene resin of 5 to 20 ffif.
The fi part and the silicone oil are comprised of 1 to 5 parts by weight, the polypropylene resin is 50 to 70 parts by weight, and the ethylene propylene rubber is 30 to 50 parts by weight.

In this resin composition, the tensile properties are improved by adding a predetermined amount of linear low-density polyethylene resin to a thermoplastic material made of polypropylene resin and ethylene propylene rubber, and the tensile properties are improved by adding a predetermined amount of silicone oil. It increases the surface smoothness of the cap product. Therefore, the insertion load of this resin composition is smaller than that of conventional engineering plastics, making insertion work easier, and the ability to prevent the clip cap from tearing when removed is almost equivalent to that of this conventional material. I can do it.

Furthermore, since the present resin composition is made of an ordinary thermoplastic resin different from engineering plastics, it is easier to process and cheaper than engineering plastics such as polyester resins.

[Example] The present invention will be explained below with reference to Examples.

In this example, using the raw materials shown in Table 1 and the predetermined mixing ratio (units are parts by weight), the shape shown in FIG. Thickness: 0.75m (thickness of other parts: 0.51m)
111) was molded by injection molding. The linear low density polyethylene resin is r20200JJ (
rPH200J (manufactured by Toshi Silicone Co., Ltd.) was used as the silicone oil, Tsukrak 200J (manufactured by Iriuchi Shinko Kagaku Co., Ltd.) was used as the stabilizer, and rPPG-7M was used as the pigment. -0011
Black (manufactured by Dainichiseika Co., Ltd.) was used. The side molding clip is large enough to be inserted into the clip cap, and polyacetal resin is used as the material. Also, the thickness of the mating sheet metal is 0.811
1. A hole with a diameter of 8,5111+1φ was used.

The physical properties of this material, namely hardness, tensile yield strength, tensile breaking strength, elongation and tear strength, were measured according to JIS K6301, and the results are shown in Table 1.

Table 1 also shows the evaluation of insertion load, removal load, and tearing upon removal (out of 10 at room temperature) for this clip cap product.

Comparative Examples 1 to 3 In Comparative Example 1, the amount of polypropylene resin blended was 45 parts by weight, and in Comparative Example 2, it was 40 parts by weight, both of which were less than 50 parts by weight, and the other composition components were the same as in Example 1. The same material is used. In Comparative Example 3, only a conventionally known polyester resin (Pelprene P40HJ (manufactured by Toyobo Co., Ltd.)) was used.

In these Comparative Examples 1 to 3, clip caps having the same shape as in Example 1 were molded in the same manner as in Example 1,
The physical properties of the material and the clip characteristics were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

(Evaluation) In this example, the insertion load of the clip cap product is significantly smaller than that of the conventional example of Comparative Example 3, indicating that the insertion workability is good.

In addition, the physical properties of the material in this example include hardness and tensile yield strength, which are almost the same as the conventional example of Comparative Example 3 and larger than Comparative Examples 1 and 2, and tearing during removal was also rated O out of 10, which is the best in comparison. It was superior to Examples 1 and 2 and equivalent to the conventional example of Comparative Example 3.

As described above, the composition of this example provides an extremely well-balanced product that is easier to insert than the conventional example of Comparative Example 3 and is less likely to tear after handling and removal.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a state in which the clip of the side molding is about to be inserted into the clip cap. FIG. 2 is a cross-sectional view of the clip cap used in this example. 1...Clip cap 2...Car body sheet metal 3...
・Nide mole clip 4...Side mole patent applicant Toyoda Gosei Co., Ltd. agent Patent attorney Hirodo Okawa Patent attorney Akio Maruyama Figure 1 Figure 2 (Unit: mm)

Claims (1)

[Claims] (1) The total amount of polypropylene resin and ethylene propylene rubber is 100 parts by weight, linear low density polyethylene resin is 5 to 20 parts by weight, and silicone oil is 1 to 5 parts by weight, and the polypropylene resin is 50 to 70 parts by weight. A polypropylene resin composition characterized in that the ethylene propylene rubber is 30 to 50 parts by weight.