JPS6198756A - Hollow bottle with excellent low-temperature impact resistance - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to polypropylene compositions with excellent low temperature impact resistance, and more particularly to polypropylene compositions particularly suitable for hollow bottle applications.

PRIOR ART AND TECHNICAL PROBLEMS TO BE SOLVED Polypropylene has good rigidity and transparency, and is also excellent in chemical resistance and hygienic properties, so it is attracting attention for its use in hollow bottles. However, since polypropylene for hollow bottles is required to have low-temperature drop impact strength, which is a drawback of polypropylene, it is essential to improve the low-temperature impact resistance.

Research has been carried out to improve low-temperature impact resistance by blending polypropylene with other polyolefins, but since rigidity, transparency and low-temperature impact resistance have a trade-off relationship, it is difficult to balance them. The current situation is that...

OBJECT AND SUMMARY OF THE INVENTION An object of the present invention is to provide a polypropylene composition that has excellent rigidity, transparency, and low-temperature impact resistance.

Another object of the invention is to provide a polypropylene composition particularly suitable for use as a hollow bottle.

According to the present invention, 70 to 90 parts by weight of polypropylene resin, 5 to 20 parts by weight of linear low density polyethylene (hereinafter sometimes referred to as LLDPE), and 2 parts by weight of soft elastomer.
A polypropylene composition having excellent low-temperature impact resistance is provided by blending 20 to 20 parts by weight of the polypropylene composition.

Structure of the Invention As the polypropylene resin used in the present invention (d
In addition to a polypropylene homopolymer, random copolymers with other olefins may be used as long as the properties of polypropylene such as transparency and rigidity are not impaired.

In addition, this polypropylene resin has a density of 0.9[
1 to 0.915'/cd is preferably used, and from the viewpoint of moldability etc., the melt flow rate (hereinafter referred to as MFR) is preferably used.
) is 0.1 to 3.0f/10min (AS
According to the method of TM-D-1238, 190C5216C
The value measured under a load of 1 (hereinafter the same shall apply) is preferably within the range.

The linear low-density polyethylene used in the present invention has several characteristics that are not found in commonly used high-pressure low-density polyethylene and low-pressure high-density polyethylene.

That is, high-pressure low-density polyethylene has a molecular structure with long chain branches and is a single polymer of ethylene, whereas linear low-density polyethylene has a substantially straight-chain molecular structure and consists of ethylene and carbon. It consists of a copolymer with 4 to 8 α-olefins. On the other hand, low pressure high density polyethylene has a density (25C) of 0.940 to 0.965 f/c
rd range, and its molecular structure has almost no short branched chains, whereas linear low density polyethylene has a density in the range of 0.915 to 0.935 r/cd, It is different in that it has a short branched chain derived from the α-olefin mentioned above.

Comonomers in this linear low density polyethylene include butene-1, pentene-1,4-methylpentene-
1, hexene-L 2-Methyl-butene-1, octene-1 and other α-olefins having 4 to 8 carbon atoms can be mentioned, and these α-olefins have 1 to 20 carbon atoms per total.
It is incorporated into the polymer chain in an amount of 6% to 15% by weight, especially 6 to 15% by weight.

This linear low-density polyethylene (L-LDpE) is also used in other olefins as mentioned above [-Related to Nenka Togazo, for example, high-pressure low-density polyethylene CHP4LDI]
), high density polyethylene (IIDPE), crystalline propylene ethylene copolymer CPPE), etc.
They have differences in physical properties as shown in Table 7 below.

Table 7 Tree 1 Town Elongation (related) Strength (Kq, y) Melting point <C) L-LDPE 850', soo
10'/) ~122UP-ILDPE (SO
D '170'' 94~114HDPE
8[']0 230"-118~13roP
PE 800 330 125-153
From Table A above, linear low density polyethylene blended with polypropylene resin has high elongation and strength.
However, it is clear that it has the characteristic of having a low melting point.

In the present invention, these linear low density poly, r-f
-v n (7) f mo M F R ka 0.1 乃'M
1'-0? /10 m- is preferably used.

Furthermore, the soft elastomers used in the present invention include copolymer elastomers of ethylene and monofins such as propylene, butene, hexene, octene, and decene;
Copolymer elastomers of propylene/μ butene, hexene/, octene, decene, etc.; co-9 copolymer elastomers of butene and hexene, octene, decene g, c; copolymer elastomers of hexene, octene, decene, etc. are preferably used, especially those with a density of 0.87 to 0.89
Y/crt1. ．． 11 and 5fFR is 0.1 to 40f
/10 mm is preferable.

According to the present invention, the above polypropylene resin 70 to 9
0 parts by weight, especially 75 to 85 polymerized parts, 7,7. D P
E 5 to 25 parts by weight, especially 15 to 20 parts by weight, and 2 to 20 parts by weight of soft elastomer, especially 5 to 10 parts by weight.
Blend parts by weight 1. to prepare a polypropylene composition.

Such a polypropylene composition in the present invention has rigidity,
In addition to excellent transparency, as shown in the examples below, impact resistance at low temperatures is significantly improved, making it particularly suitable for use as hollow bottles.

If the amount of polypropylene resin used is greater than the above range, the resulting product will be unsatisfactory in terms of cold resistance at low temperatures, and if it is less than the above range, the resulting product will be unsatisfactory in terms of rigidity, transparency, etc. specific to polypropylene.

Therefore, similar problems will occur if the amount of LLDPE and soft elastomer is less than or greater than the above range. That is, polypropylene (
By blending grease-resistant, LLDPE, and soft elastomers, polypropylene compositions with excellent combinations of stiffness, transparency, and low-temperature impact resistance are obtained.

In the present invention, various methods can be used to blend these components, such as mechanically mixing the solid components, blending them in a melt state, blending them in a solution state, etc. The method of blending in the state is most suitable.

The invention is illustrated by the following example.

Example 1 Polypropylene homopolymer (MF RO, 5t/10cm, density 0.91f/c) was used as the polypropylene resin.
rl ) and L-LDPE (i, fFR2,0
= i/1Qmin, density 0.9211tlcrd) and a soft elastomer (MF RO, 4f/10mm, density 0.880S'/cril) according to the formulation shown in Table 1 below to prepare a polypropylene composition (sample 1).
-5) were prepared.

Table 1 Using this composition, cylindrical bottles (400CC1202, thickness 0, 7 m) were prepared by blow molding and sheet molding, respectively.
), a sheet (2 to 3 cm thick) was molded, and various physical properties were measured. The results are shown in Table 2.

Example 2 Polypropylene resin was a random copolymer of polypropylene (MF RO, 5?/10 m1n, density 0.
Sample 1 of Example 1 except that 91 tlcrd) was used.
A polypropylene composition was prepared by the same formulation as Sample 6.7.8), and a hollow bottle and a sheet 't' were prepared in the same manner. ':f. These various physical properties are also shown in Table 2.

Example 6 A polypropylene composition was prepared in the same manner as Sample 1 of Example 1, except that a polypropylene block copolymer (LfF R0,5?/10 m1n, density 0,91?/crtl) was used as the polypropylene resin. Sample 9) was prepared, and a hollow bottle and sheet were obtained in the same manner.

The physical properties are shown in Table 2.

Example 4 For comparison, a polypropylene homopolymer (A#R0
, 5r, /10 order, density 0.91 10 tl), Rantam copolymer CMFR0,5? /10mm Density 0, 9
15'/crtL), and block copolymer (AI
PRO, 5? / 10mt/I, density 0.915'
/C+4) were used alone to obtain hollow bottles and sheets (sample 10.11.12). Table 2 shows the physical properties of each of these companies.

Claims (2)

[Claims] (1) A polypropylene composition with excellent low-temperature impact resistance, which is made by blending 70 to 90 parts by weight of a polypropylene resin, 5 to 20 parts by weight of linear low-density polyethylene, and 2 to 20 parts by weight of a soft elastomer. (2) The polypropylene composition according to claim 1, wherein the polypropylene resin is a homopolymer of polypropylene or a random copolymer of polypropylene and another olefin.