JPS5839853B2 - Kiyoka Polypropylene Seibutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel highly reinforced reinforced polypropylene compositions comprising glass fibers and vinylon fibers.

Conventionally, polypropylene has been widely used in various fields because it has excellent properties such as low cost, light weight, and good chemical stability.

However, when used as so-called engineering plastics or in similar fields, mold shrinkage is high and mechanical strength is generally low.
There were problems such as insufficient heat resistance, and the fields of use were often limited.

Therefore, various studies have been conducted to compensate for these drawbacks, and various reinforced polypropylenes have already been proposed.

For example, one method is to add and mix inorganic fibers such as glass fibers to polypropylene to improve its heat resistance, mechanical strength, etc.

However, simply mixing inorganic fibers such as glass fibers with polypropylene does not necessarily provide a sufficient improvement effect on polypropylene.

As a result of intensive research on improving the mechanical strength and heat resistance of reinforced polypropylene, the inventors of the present invention found that it is possible to mix both glass fiber and vinylon fiber, which is one of the so-called organic fibers, with polypropylene. It was discovered that the mechanical strength, especially the rigidity, was significantly improved, and the present invention was completed.

That is, the present invention is a reinforced polypropylene composition prepared by blending and kneading polypropylene, glass fiber, and vinylon fiber in the proportions shown in the following formula.

In the present invention, as polypropylene, not only a crystalline propylene homopolymer but also a crystalline propylene copolymer obtained by copolymerizing a small amount of olefin such as ethylene or butene in a random or block manner can be used.

Moreover, the vinylon fiber as used in the present invention is a vinylon fiber obtained by acetalizing polyvinyl alcohol fiber with formaldehyde or the like, and is generally commercially available vinylon fiber, and those having a length of 10 mm or less are particularly preferably used.

The blending amount thereof is preferably in the range of 1 to 50% by weight, particularly 5 to 30% by weight, based on the total amount of polypropylene and glass fiber.

If the blending amount is less than 1% by weight, almost no effect will be obtained;
If it exceeds 0% by weight, various physical properties of FRPP, such as a decrease in water resistance, are exhibited, which is not preferable.

The glass fibers may be commercially available glass fibers, either roving (long fibers) or chopped strands (short fibers), preferably those whose surfaces have been treated with a silane compound, an epoxy compound, or the like.

The compounding amount is the following formula The range shown in is preferable.

If it is less than 5% by weight, no effect can be obtained, while if it exceeds 50% by weight, it becomes brittle, which is not preferable.

The composition of the present invention can be obtained by kneading using a conventional method such as a Bamba IJ mixer, an extruder, or a roll.

Furthermore, the present invention will not be hindered even if additives such as antioxidants, ultraviolet absorbers, and lubricants are appropriately added to this composition.

The feature of the present invention lies in the combined use of glass fiber and vinylon fiber as reinforcing agents for polypropylene, which allows: (1) indirect compatibility improvement between polypropylene and glass fiber by making vinylon exist as an intermediate matrix for glass fiber (2) By using vinylon fibers, there is less damage to the glass fibers during kneading.

■ Reinforcing effect of the vinylon fiber itself ■ Effects such as improved dispersibility due to the entanglement of the vinylon fiber and glass fiber are thought to contribute to the improvement in mechanical strength, particularly the remarkable improvement in rigidity.

The present invention will be specifically described below with reference to Examples, but the present invention is of course not limited to these Examples.

Example 1 Sumitomo Noblen W502 (melt index: 8
homopolymer) treated with organic silane (fiber diameter 13μ, convergence number 800 (manufactured by Nittobo, F
Glass fiber for RPP (C86-PE403) and vinylon fiber (fiber length 1.0 x 6 denier) were triblended with the compositions shown in Table 1.

Next, the triblend product obtained as described above was passed through a 30 m 1φ extruder manufactured by Tanabe Plastics (L/D=20.C
Kneading and granulation were performed at 1R, = 2.7).

Extrusion conditions O temperature conditions resin temperature 200℃ (C1180℃ C2200℃ H2O0℃D195℃
) Screw rotation speed 7 Orpm Next, the test piece for measuring physical properties was dehumidified using a Toshiba Machine Model 15 125A injection molding machine.

Injection conditions ○ Injection pressure; 75 kg/cni gaugeO Resin temperature: 250°C (C, 220'CC2240°C C325o°CDH24
5° C.) O Mold temperature: 50° C. ○ Screw rotation speed: 50 rpm ○ Molding cycle: Injection 5 See holding pressure 10 sec Cooling 45 sec ○ Mold; Test piece mold The physical property measurement results are shown in Table 2.

As described above, the addition has a significant effect on bending stiffness.

Claims (1)

[Scope of Claims] 1. A reinforced polypropylene composition characterized in that it is made by blending and kneading polypropylene and fibers in the proportions shown in the following formula: glass fiber and vinylon.