JPH11181180A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin compsn. which can give a molded article having high strengths and dimensional accuracy by compounding a polypropylene resin with glass fibers and a modified polypropylene resin in a specified ratio. SOLUTION: This compsn. is prepd. by compounding 100 pts.wt. polypropylene resin (A) with 20-80 pts.wt. glass fibers (B) and 0.5-20 pts.wt. modified polypropylene resin (C). A propylene homopolymer or copolymer with an α-olefin having a melt flow rate of 1-47 g/10 min is pref. as ingredient A. Pref., ingredient B is E-glass fibers having an average fiber diameter of 7-15 μm. Pref., ingredient C is polypropylene modified by the graft polymn. of maleic acid or maleic anhydride and has a content of maleic acid or maleic anhydride of 0.1-3.0%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition having excellent moldability such as injection molding and having high mechanical strength.

[0002]

2. Description of the Related Art Conventionally, in order to improve the strength of polypropylene, it has been generally practiced to improve the impact strength by blending an elastomer or to improve the strength by blending glass fibers. However, none of the strengths were satisfactory.

[0003]

An object of the present invention is to provide a resin composition having a high strength that cannot be obtained with a conventional resin composition and a molded article having good dimensional accuracy can be obtained. It is in.

[0004]

The present invention relates to (a) 100 parts by weight of a polypropylene resin and (b) glass fiber 2
0 to 80 parts by weight (c) modified polypropylene resin 0.5 to
It is a resin composition containing 20 parts by weight. Preferably, the polypropylene resin (a) is a homo-type polypropylene resin or a copolymer of propylene and an α-olefin, and has a melt flow of 1 to 47 g / 10 minutes,
Glass fiber (b) has an average fiber diameter of 7 to 15 μm,
The modified polypropylene resin (c) is a polypropylene resin modified with maleic acid or maleic anhydride, and is a resin composition in which maleic acid or maleic anhydride has a content of 0.1 to 3.0%.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polypropylene resin (a) used in the present invention is a commercially available product, which is a homopolymer of propylene or a copolymer of propylene and an α-olefin other than propylene. Yes, those having a melt flow of 1 to 47 g / 10 minutes are preferred. Examples of the α-olefin include ethylene, butene, hexene, and heptene. Block copolymers or random copolymers containing propylene and one or two of these α-olefins may be used. Among these, homopolymers of propylene, which is a homopolymer, are generally preferred because of their generally good thermal stability. The polypropylene resin (a) has a melt flow of 1
In the case of less than g / 10 minutes, a sufficient molded product cannot be obtained due to poor moldability. If the melt flow exceeds 47 g / 10 minutes, it is difficult to obtain a molded product having sufficient strength.

The glass fiber (b) used in the present invention is:
It is preferably E glass having a fiber diameter of 7 to 15 μm.
Further, the glass fiber is a surface-treated one, and a sizing agent, a surface-treating agent is a urethane-based, epoxy-based, acrylic-based, amino-based silane coupling agent, or the like, particularly preferably a urethane-based or amino-based one . In addition, maleic acid-modified polypropylene in the glass fiber surface treatment,
A mixture of maleic anhydride-modified polypropylene, maleic anhydride-modified polyolefin, or maleic anhydride-modified polyolefin mixed with a surface treating agent and attached to glass fibers is preferable because the strength of the resin composition is further improved. The glass fiber (b) has a good reinforcing effect when the fiber diameter is less than 7 μm, but the molded article is easily warped or deformed because the directionality is strong, and the reinforcing effect is reduced when the fiber diameter exceeds 15 μm, Moldability also decreases. These glass fibers (b) are contained in an amount of 20 to 80 parts by weight based on 100 parts by weight of the polypropylene resin (a). If the amount is less than 20 parts by weight, the reinforcing effect is small and the strength is low.

The modified polypropylene resin (c) used in the present invention is a polypropylene modified by grafting with maleic acid or maleic anhydride, and the content of maleic acid or maleic anhydride is 0.1 to 3. Those having 0%, an acid value of 4 to 15, a number average molecular weight of 20,000 to 50,000, and a weight average molecular weight of 40,000 to 110,000 are preferable. If the modified polypropylene resin (c) has a maleic acid or maleic anhydride content of less than 0.1%, the effect of improving mechanical strength cannot be sufficiently obtained, and even if it exceeds 3%, the effect of improving strength is 3% or less. The modified polypropylene resin (c), which is not much different from the one having the content of
0.5 to 20 parts by weight with respect to 0 parts by weight. 0.
If the amount is less than 5 parts by weight, the effect of improving mechanical strength is insufficient,
Even if it is added in excess of 20 parts by weight, the effect of improving strength is small.

[0008] The method for producing the composition of the present invention is obtained, for example, by weighing the components, mixing them with a blender, a mixer or the like, and performing melt-kneading pelletizing with an extruder. In this case, other components, for example, as a filler,
Talc, mica, wollastonite, clay, zinc oxide,
An appropriate amount of a metal filler, calcium carbonate, carbon black, carbon fiber, or an elastomer component, a heat stabilizer, an antioxidant, a weathering agent, a lubricant, a pigment, or the like may be added as an impact modifier. The molding material in the form of a pellet obtained in this way is usually used for a thermoplastic resin molding machine,
For example, it is molded into a desired shape by an injection molding machine or an injection compression molding machine and used.

[0009]

EXAMPLES The present invention will be described below by way of examples, which are merely examples, and the present invention is not limited to these examples. << Examples 1-5 >> As the component (a), polypropylene,
Noblen Z101B (PP1, manufactured by Sumitomo Chemical Co., Ltd., melt flow; 27 g / 10 minutes) was used, and as the component (b), glass fiber, RES03X-TPG1296 (G
F: made of Nippon Glass Fiber, average fiber diameter: 10 μm), and as the component (c), a modified polypropylene resin modified with maleic anhydride (m-PP, maleic anhydride content; 0.5%) It was used. << Comparative Examples 1-3 >> As the component (a), polypropylene,
Noblen Z101B (PP1, manufactured by Sumitomo Chemical Co., Ltd., melt flow; 27 g / 10 minutes) was used, and as the component (b), glass fiber, RES03X-TPG1296 (G
F: made of Nippon Glass Fiber, average fiber diameter: 10 μm), and as the component (c), a modified polypropylene resin modified with maleic anhydride (m-PP, maleic anhydride content; 0.5%) It was used.

[0010] Predetermined amounts of the respective components shown in Tables 1 and 2 were blended, melt-kneaded with a twin-screw kneader, and pelletized.
Further, each test piece was prepared from the obtained molding material and pellet by injection molding, and each physical property was measured. In addition, each physical property measurement was performed by the following test methods and conditions. The results are shown in Tables 1 and 2. Of the comparative examples, Comparative Examples 1 and 2 have low strength, and Comparative Example 3 cannot be molded due to poor molding due to low fluidity. Flexural strength: ASTM D790 IZOD Impact value: ASTM D256 (with notch) Tensile strength: ASTM D628

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

According to the present invention, a composition having excellent mechanical strength properties can be obtained, and can be used in fields where polypropylene resins have not been used because of insufficient strength.

Claims (4)

[Claims] 1. A resin comprising (a) 100 parts by weight of a polypropylene resin, (b) 20 to 80 parts by weight of a glass fiber, and (c) 0.5 to 20 parts by weight of a modified polypropylene resin. Composition. 2. The polypropylene resin (a) is a homo-type polypropylene resin or a copolymer of propylene and an α-olefin, and has a melt flow of 1 to 47 g / 1.
The resin composition according to claim 1, wherein the time is 0 minutes. 3. The glass fiber (b) has an average fiber diameter of 7-1.
3. The resin composition according to claim 1, which has a thickness of 5 μm. 4. The modified polypropylene resin (c) is a polypropylene resin modified with maleic acid or maleic anhydride, wherein the amount of maleic acid or maleic anhydride is 0.1 to 10%.
The resin composition according to claim 1, which has a content of 3.0%.