JPS5817140A - Novel polypropylene resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having excellent rigidity, surface gloss and resistance to impact and whitening by impact, by blending a lamellar filler, an amorphous ethylene/butene copolymer and a dispersant with a crystalline ethylene/propylene block copolymer. CONSTITUTION:10-40wt% lamellar filler, such as talc, having an average particle size of 4mu or below as measured by a centrifugal granulometer, 5-20wt% amorphous ethylene/butene copolymer having an ethylene content of 75-90wt% and an intrinsic viscosity of 1.5 or below as measured in xylene soln. at 70 deg.C, and 0.3-1.5wt% dispersant selected from 18-22C satd. fatty acids and metal salts thereof, such as calcium stearate, are blended with a crystalline ethylene/ propylene block copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene resin composition that is excellent in rigidity, impact resistance, surface gloss of molded articles, and impact whitening resistance. More specifically, ξ is mainly composed of a crystalline ethylene-propylene block copolymer, and contains a plate-like filler and a non-grade ethylene-butene copolymer. A polypropylene resin composition with excellent surface gloss and impact whitening resistance. Conventional polypropylene, talc, and clay.

Various resin compositions have been developed that have improved rigidity and heat resistance simply by incorporating fillers such as caldolam carbonate. In addition, as a means to improve the impact strength of polypropylene containing these inorganic fillers, an amorphous ethylene-propylene copolymer and other polymeric components such as, /,! , 9A, , □-U, 1,4-dicyclopentadiene, styrene-butadiene rubber, etc. have been proposed to be blended with a multi-component copolymer having rubber-like properties. However, these compositions have the disadvantage that the surface gloss of the molded article is significantly impaired and that the molded article is susceptible to impact whitening.

Regarding the improvement of the surface gloss of polypropylene blended with inorganic fillers, Japanese Patent Publication No. 6g-8874 found that the intrinsic viscosity measured in a xylene solution of 2P or less barium sulfate and 70°C was 1.
A composition containing a non-quality ethylene-propylene copolymer with a stiffness of 9 or less has been proposed, but the stiffness is 18,000.
%p/d or less. Furthermore, the impact whitening resistance has not been improved at all. Therefore,
It has not yet been possible to obtain a polypropylene-inorganic filler composition that has a rigidity of tsooo or more, has excellent impact resistance and surface gloss of a molded article, and is resistant to impact whitening.

The object of the present invention is to withstand a rigidity of 18,000%=/d or more.

In order to achieve the above object, the present invention mainly consists of a crystalline ethylene-propylene block copolymer with an average particle diameter of 4.
Platy fillers of less than μ are included in the composition with 1O10N40% and 7
The intrinsic viscosity measured in a xylene solution at 0°C is 1.6 or less, and the ethylene composition ratio in the copolymer is 76 to 9 Qvt%.
Shimaboku relates to a polypropylene resin composition containing 6 to 20 vt% of a non-quality ethylene-carbon copolymer and 0.8 to 1.6 W** of a dispersant.

The present invention will be explained in more detail below.

The crystalline ethylene-propylene block copolymer used in the present invention is an ethylene-propylene block copolymer in which only propylene is polymerized in the presence of a propylene polymerization catalyst, and then ethylene and propylene are copolymerized.

The plate-shaped filler used in the present invention preferably has an average particle diameter of 4p or less as measured by a centrifugal sedimentation viscometer, and is 3μ
The following are more preferred.

If the average particle diameter exceeds 4μ, the problem is that the surface gloss of the molded product is significantly impaired. As the plate-like filler, talc and mica are preferable.The amount of filler used is ζ1 in the resin composition.
0 to 4 Q vt%, preferably 15 to 80 Wt4. 4 (If the filling exceeds lvt%, the surface gloss will not only decrease, but also the impact strength will decrease, and the AM dynamics will decrease significantly. If it is less than btovt*, the contribution of rigidity and heat resistance will be small (balanced). The amorphous ethylene-butene copolymer used in the present invention, for which no physical properties can be obtained, is a copolymer of ethylene and butyne-1 that has rubber-like properties. The intrinsic viscosity determined by is preferably 1.6 or less, and the ethylene composition ratio in the copolymer is preferably T6 to ilQwt%* $10-90vt
% is more preferable.

The intrinsic viscosity measured with a xylene solution at 70°C is t, S*
If it exceeds it, the fluidity of the resin composition will be reduced and the dispersibility in the resin will be poor, resulting in a marked reduction in the surface gloss of the molded product.

If the ethylene composition ratio is less than 696%, the stiffness and impact whitening resistance of the composition will deteriorate, and if it is more than 9Qvt%, the impact strength will decrease. The amount of amorphous ethylene-butene polymer used in the resin composition is 6~! Qvt96
It is desirable that ξ is preferably 5 to 15 vt%.
If the usage amount exceeds 2Qvt%, it becomes rigid.

Heat resistance decreases, and it is difficult to obtain well-balanced physical properties, and if it is less than 5 vt%, the contribution to improving impact resistance is small.

The dispersant used in the present invention is preferably a saturated fatty acid of Cts to C0 and a metal salt thereof, and more preferably potassium stearate or behenic acid. The amount used is 0.
8-1.5vt96 is preferred.

There are no particular technical difficulties in the production of the new polypropylene resin composition in Honjitsu@. It is possible to apply Yoko etc., but Bunbury is preferred.

The polypropylene resin composition according to the present invention contains 5IIr iris antioxidants, ultraviolet absorbers, lubricants, and pigments conventionally used in polypropylene.

There is no problem even if additives such as antistatic agents and antistatic agents are added. The amount used is generally sufficient for polypropylene.

Examples will be shown below to clarify the scope of the present invention. The bending rigidity and surface gloss are respectively SrmD790 and
JI8 z87411c Yoqte II fixed, t=. Drop impact strength was measured using the De-Epon method in a measurement atmosphere of 0°C. To measure rit impact whitening, a 1 bottle falling weight was dropped from the height of gos and the whitening area was measured.

Examples 1 to 3 Crystalline ethylene-propylene block copolymer (ethylene content gvt%, MI-3) with talc having an average particle size of 8p and viscosity [η) measured in a 70°C xylene solution
= 1.0, the ethylene composition ratio in the copolymer is 85 wt%
A non-quality ethylene-butene copolymer and calcium stearate were examined in the composition shown in the table, and after mixing in a Henschel mixer for 4 minutes, they were kneaded at a temperature of 180 to 220 °C with a Banbury kneader. , pelletized after roll sheeting. A test piece was molded from this pellet using a screw-in-line injection molding machine at a resin temperature of gso° C., and the bending rigidity, falling weight impact strength, surface gloss of the molded product, and impact whitening resistance were measured.

Table #Ii shows these measurement results in comparison with Control Examples 1 to 10.

Claims (1)

[Claims] (1) Platy filler 10 mainly composed of crystalline ethylene-propylene block copolymer and having an average particle size of 4μ or less
~4 Q wt%, TO °C 20 wt% and dispersant 0.8~L,S
1. A polypropylene resin composition characterized in that wt% (each based on the weight of the composition) is blended. (Rose) Claim 1 in which the plate-shaped filler is one talc.
Composition of the Xiang period. (ml) The composition according to claim 1, wherein the plate-like filler is mica.