JPS5958049A - Polyolefin resin composition - Google Patents

Abstract

PURPOSE:To prepare a polyolefin composition having excellent vacuum-forming property and tensile elongation, by compounding a specific high-density polyethylene to an ethylene-propylene block copolymer or its mixture with a propylene homopolymer. CONSTITUTION:60-80wt% of an ethylene-propylene block copolymer or its mixture with a propylene homopolymer is compounded with 20-40wt% of a high- density polyethylene having a ratio of (melt viscosity)/(melt tension) of 3X10<4>- 5X10<4> poise/g at 190 deg.C under shear rate of 6sec<-1>. The melt flow rate of the ethylene-propylene copolymer or its mixture is preferably <=1g/10min at 230 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyolefin resin J having excellent vacuum formability and tensile elongation properties.

Conventionally, polypropylene resin has excellent properties, but
Vacuum formability is poor due to the amount of sagging during vacuum forming, and as an improvement measure a method of blending polyethylene is used. However, if polyethylene is added too little, sufficient vacuum formability cannot be obtained, while if the amount added is increased to improve vacuum formability, the tensile elongation rate decreases, impairing the inherent properties of polypropylene. have.

As a result of research to improve these drawbacks, the present invention has been developed by combining ethylene-propylene bronc! ! By adding high-density polyethylene, which has a large ratio of melt viscosity to melt tension, to a mixture of polypropylene and a polypropylene homopolymer, the compatibility between polypropylene and polyethylene is increased, resulting in excellent vacuum formability and tensile elongation. It has been found that a polyolefin resin composition can be obtained.

That is, the ethylene-propylene broth copolymer alone or a mixture of this and a polypropylene homopolymer 6
Ratio of melt viscosity and melt tension at 0 to 80 weight ratio and 190℃ shear rate 5SeC-'3X10A-5XIO
'Boys/gr high density polyethylene 20~40
It is characterized by containing a heavy fa%. Invention 1 The polypropylene used in this invention may be an ethylene-propylene pro-tox copolymer alone, or a mixture of this and a polypropylene homopolymer, and the mixing ratio may be arbitrary.
To reduce sagging due to heating during air molding,
Melt flow rate (MFR) at 30°C or 1 g
r/I Q min or less is preferable. Also 1
The high-density polyethylene used in the present invention has a melt viscosity/melt tension ratio of 1 or 3 at a shear rate of 6 sec-' at 190°C.
If the tensile extensibility of the resin composition does not reach x10' voids/gr, it is low, and if it exceeds 5 x 104 voids/gr, the sagging during heating for vacuum forming becomes large and the vacuum formability is impaired, so this is preferable. do not have. Furthermore, if the amount of high-density polyethylene blended increases, the vacuum formability will improve or the heat resistance will decrease, and if the blended amount is small, the vacuum formability will deteriorate. be.

Next, the present invention will be explained in detail.

Example】 Ethylene-propylene block JCff1 combination.

(MpR = o, s), 30% by weight of polypropylene homopolymer (MFR = 0.5), high-density polyethylene with a melt viscosity/melt tension of 4 X 10'° voids/g r (MFR-03) at 40 weight qII
Blend to obtain a resin composition. Extrude this to 40 mmφ (
L/D=26. CR=30), and the amount of sagging and tensile elongation during vacuum forming were measured. The results are shown in Table 1.

Example 2 A resin composition was obtained by blending the same ethylene-propylene block copolymer as in Example 1 with 40 wt ffi% of 60 wt 1 L high-density polyethylene. Form this into a plate shape in the same way,
The amount of sagging and tensile elongation during vacuum forming were measured.

The results are shown in Table 1.

Comparative Example 1 A resin composition was obtained by blending 50% by weight of the same ethylene-propylene block copolymer as in Example 1 and 50% by weight of a polypropylene homopolymer.

Comparative Example 2 The same ethylene-propylene copolymer as in Example 1 was used in a 30-fold ratio, and the polypropylene homopolymer was used in a 30-fold ratio.
fi%, melt viscosity/melt tension value or 2XIO'voise/
gr high density polyethylene (MFR=03)
A resin composition was obtained by blending the resin composition with heavy ffi%.

Comparative Example 3 A resin composition was obtained by blending the same ethylene-propylene block copolymer as in Example 1 at 60 weight percent and the same high-density polyethylene as in Comparative Example 2 at 40 weight percent.

The resin compositions of the above comparative examples were similarly molded into plate shapes, and the amount of sag and tensile elongation during vacuum forming were measured. Table 1 shows the results.

Comparative Example 4 The same ethylene-propylene broth copolymer as in Example was molded into a single plate, and Table 1 shows the measurement results of the sag width and tensile elongation during vacuum molding.

Table 1 As is clear from Table 1, the present invention reduces the sagging of the sheet due to heating during vacuum forming, resulting in improved vacuum formability and easy vacuum forming of large areas. It's sweet.
The industrial application of the present invention is extremely large in that it has good tensile elongation and can improve vacuum formability without impairing the inherent properties of polypropylene.

patent applicant

Claims (1)

[Claims] 60 to 80% by weight of ethylene-propylene broth copolymer alone or a mixture of this and polypropylene homopolymer, and a shear rate of 190° C.) 6 sec""'
The ratio of melt viscosity and melt tension is 3Xl O'~5X
High-density polyethylene with lO'boys/gr 20
A polyolefin resin composition characterized in that it contains a polyolefin resin composition of .about.40% by weight.