JPH09227729A - Polyolefin resin composition and polyolefin film obtained by molding processing thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyolefin resin composition suitable for hightemperature processing and excellent in heat resistance and resistance to (pink)-discoloration by incorporating a polyolefin resin with a specific phenolic antioxidant and a specific compound capable of suppressing/preventing the composition from discoloration. SOLUTION: This resin composition is obtained by incorporating (A) 100 pts.wt. of a polyolefin resin with (B) pref. 0.01-0.50 pts.wt. of n-octadecyl-3-(4'- hydroxyl-3',5'-di-t-butylphenyl)propionate and (C) pref. 0.01-0.50 pts.wt. of bis(2,6- di-t-butyl-4-methylphenyl)pentaerythritol-di-lphosphite, and furthermore pref. (D) a metallic soap (esp. pref. zinc stearate). The component C may be distearyl pentaerythritol diphosphite or bis(2,4-di-t-butylphenyl)pentaerythritol-di-phosphite, instead of bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol-di-phosphite.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyolefin resin composition suitable for high temperature processing and excellent in heat resistance and discoloration resistance (pink discoloration resistance), and a polyolefin film obtained by molding the polyolefin resin composition. Regarding

[0002]

2. Description of the Related Art A polyolefin resin composition contains a phenolic antioxidant and an organic phosphite in order to prevent or prevent a decrease in mechanical strength and yellowing of a molded product due to thermal deterioration of the polyolefin due to heating during molding. It is known to be added in combination with a system compound (Japanese Patent Publication No. 56-2593).
No. 4). Although the polyolefin resin composition described in this publication is effective against various problems associated with the above-described heat deterioration of the polyolefin, it has another problem. That is, when a molded product using the polyolefin resin composition described in the publication is stored at room temperature for a long period of time, the molded product has a problem that its color changes to yellow, brown, or pink. Such discoloration is considered to be caused by the phenolic antioxidant present in the molded product, and such discoloration is particularly noticeable in white and transparent products and thin molded products such as films, and as a problem that reduces the commercial value. A solution was desired.

[0003]

The object of the present invention is to provide a polyolefin resin composition which is not thermally deteriorated by heating during molding, and even when the molded product is stored at room temperature for a long period of time.
It is an object of the present invention to provide a polyolefin resin composition in which a molded article does not discolor yellow, brown, or pink, and a film obtained by molding the polyolefin resin composition.

[0004]

A first invention is a polyolefin resin containing n-octadecyl-3- (4'-hydroxyl-3 ', 5'-di-t-butylphenyl) propionate and bis (2,6). -Di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite is incorporated into the polyolefin resin composition.

A second aspect of the present invention is a polyolefin resin containing n-
Octadecyl-3- (4'-hydroxyl-3 ', 5'
-Di-t-butylphenyl) propionate and distearyl pentaerythritol diphosphite are blended.

[0006] A third aspect of the present invention relates to a polyolefin resin containing n-
Octadecyl-3- (4'-hydroxyl-3 ', 5'
A polyolefin resin composition comprising: -di-t-butylphenyl) propionate and bis (2,4-di-t-butyl-phenyl) pentaerythritol-di-phosphite.

A fourth aspect of the present invention relates to a polyolefin resin containing tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane and bis (2,6-di-). A polyolefin resin composition comprising t-butyl-4-methylphenyl) pentaerythritol-di-phosphite.

A fifth aspect of the invention is the polyolefin resin composition according to any one of the first to fourth aspects of the invention, characterized in that a metal soap is blended.

A sixth invention is a polyolefin resin 100.
0.01 to 0.50 parts by weight of n-octadecyl-3- (4′-hydroxyl-3 ′, 5′-di-t-butylphenyl) propionate is blended with respect to parts by weight. The polyolefin resin composition according to any one of the first to third inventions or the fifth invention.

A seventh invention is a polyolefin resin 100.
With respect to parts by weight, bis (2,6-di-t-butyl-4-
Methylphenyl) pentaerythritol-di-phosphite is blended in an amount of 0.01 to 0.50 parts by weight, which is the polyolefin resin composition according to either the first invention or the fifth invention.

The eighth invention is a polyolefin resin 100.
0.01 to 0.50 parts by weight of distearyl pentaerythritol diphosphite is blended with respect to parts by weight, which is the polyolefin resin composition according to the second invention or the fifth invention.

A ninth invention is a polyolefin resin 100.
Based on parts by weight, bis (2,4-di-t-butyl-phenyl) pentaerythritol-di-phosphite was added at 0.
The polyolefin resin composition according to either the third invention or the fifth invention is characterized in that the polyolefin resin composition is blended in an amount of from 01 to 0.50 parts by weight.

A tenth invention is a polyolefin resin 10
The polyolefin resin composition according to any one of the fifth to ninth inventions, characterized in that 0.01 to 5.0 parts by weight of metal soap is mixed with 0 parts by weight.

An eleventh invention is the polyolefin resin composition according to any one of the fifth to tenth inventions, wherein the metal soap is a fatty acid metal salt of lithium, magnesium, calcium or zinc. is there.

A twelfth invention is the polyolefin resin composition according to any one of the fifth invention to the eleventh invention, wherein the metal soap is zinc stearate.

The thirteenth invention is the first to twelfth inventions.
A polyolefin film formed by molding the polyolefin resin composition according to any one of the inventions.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The polyolefin resin used in the present invention includes low-density, medium-density, and high-density polyethylene, and polypropylene includes homo, block, and
Random polypropylene etc. are mentioned. In particular, since it is formed into a film, MFR (190 ° C / 2.1
6 kg load) is 0.1 to 50 g / 10 min. It is preferable that the MFR (190 ° C./2.16 kg load) is 0.1 to 10 g / 10 min. Are preferred. MFR is 0.1 g / 10 min. If it is less than this, the melt viscosity is high and semen molding is difficult, so molding at a higher temperature becomes necessary, and it becomes difficult to control the film thickness to a constant value. On the other hand, MFR is 50g / 10
min. If it exceeds, it is difficult to control the film thickness to be constant because the melt viscosity is low.

N-octadecyl-3- (4'-hydroxyl-3 ', 5'-di-t-butylphenyl) propionate and tetrakis- [methylene-3- (3', 5'-
The phenolic antioxidant such as di-t-butyl-4′-hydroxyphenyl) propionate] methane is 0.01 to 0.5 with respect to 100 parts by weight of the polyolefin resin.
0 parts by weight is preferred. If the blending amount is less than 0.01 parts by weight, it becomes difficult to suppress / prevent thermal deterioration of the resin, while if the blending amount exceeds 0.50 parts by weight, bleeding occurs on the surface of the molded product during long-term storage. there is a possibility.

Bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, distearyl pentaerythritol diphosphite, bis (2,4-di-t-butyl-phenyl) Pentaerythritol-di-phosphite and the like are yellow, brown, and
It suppresses / prevents pink discoloration, and it is preferable to add 0.01 to 0.50 parts by weight to 100 parts by weight of the polyolefin resin. If the blending amount is less than 0.01 part by weight, it becomes difficult to prevent discoloration of the molded article which is considered to be caused by the phenolic antioxidant, while the blending amount is 0.
If it exceeds 50 parts by weight, bleeding may occur on the surface of the molded product during long-term storage.

In order to impart appropriate slipperiness during molding and to smoothly perform molding, it is desirable to add 0.01 to 5.0 parts by weight of metal soap to 100 parts by weight of the polyolefin resin. If the blending amount exceeds 5.0 parts by weight,
It may reduce the mechanical strength of the film. Metal soaps include lithium, magnesium, calcium, strontium, barium, zinc, cadmium,
Examples thereof include fatty acid metal salts of various metals such as aluminum, tin and lead, and lithium, magnesium, calcium and zinc fatty acid metal salts are preferable, and zinc stearate is particularly preferable.

In the present invention, a small amount of other components may be added to the above polyolefin resin composition, if necessary. For example, ultraviolet absorbers, lubricants, antistatic agents, and other known additives for polymers can be added in required amounts.

[0022]

【Example】

Example 1 Polypropylene having MFR (190 ° C./2.16 kg load) = 10: 100 parts by weight, n-octadecyl-3-
(4'-Hydroxy-3 ', 5'-di-t-butylphenyl) propionate: 0.10 parts by weight, bis (2,6)
-Di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite: 0.01 parts by weight and zinc stearate: 0.05 parts by weight were premixed, and then 300 ° C using a T-die molding machine. Was molded into a film having a thickness of 30 μm. The obtained film was evaluated as follows, and the results are shown in Table 1.

[Evaluation of discoloration] Regarding the film left for 3 months at room temperature after molding and the film before standing, JIS
The lightness index L ^* and the chromaticness index a ^* , b ^* specified in Z8727 are obtained, and the degree of discoloration of the film left at room temperature for 3 months with respect to the film before being left
The color difference (ΔE) and Δa specified in JIS Z8730 were evaluated.

[Heat Resistance Evaluation] A tensile test was performed on the obtained film at n = 10 based on JIS K7127, and the average values of elongation and yield point were obtained.

Examples 1 to 13 and Comparative Examples 1 to 6 According to the formulations shown in Table 1, films were obtained in the same manner as in Example 1, and the films were evaluated in the same manner. The results are shown in Table 1.

[0026]

[Table 1]

Industrial Applicability According to the present invention, it is possible to obtain a polyolefin resin composition which is not easily discolored even if it is stored for a long period of time without impairing the mechanical strength of the molded product.

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Claims (13)

[Claims] 1. A polyolefin resin containing n-octadecyl-3- (4′-hydroxyl-3 ′, 5′-di-t-butylphenyl) propionate and bis (2,6-di-t).
-Butyl-4-methylphenyl) pentaerythritol-di-phosphite is blended. 2. A polyolefin resin containing n-octadecyl-3- (4′-hydroxyl-3 ′, 5′-di-t-butylphenyl) propionate and distearyl pentaerythritol diphosphite. Polyolefin resin composition. 3. A polyolefin resin containing n-octadecyl-3- (4′-hydroxyl-3 ′, 5′-di-t-butylphenyl) propionate and bis (2,4-di-t).
-Butyl-phenyl) pentaerythritol-di-phosphite is blended. 4. A polyolefin resin containing tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane and bis (2,6-di-t-butyl-). A polyolefin resin composition comprising 4-methylphenyl) pentaerythritol-di-phosphite. 5. The polyolefin resin composition according to any one of claims 1 to 4, wherein a metal soap is blended. 6. N-octadecyl-3- (4′-hydroxyl-) based on 100 parts by weight of the polyolefin resin.
The polyolefin resin composition according to any one of claims 1 to 3 or 5, wherein 0.01 to 0.50 part by weight of 3 ', 5'-di-t-butylphenyl) propionate is blended. 7. The amount of bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite is 0.0 based on 100 parts by weight of the polyolefin resin.
1 to 0.50 parts by weight are blended.
Or the polyolefin resin composition according to any one of 5 above. 8. The polyolefin resin composition according to claim 2, wherein 0.01 to 0.50 parts by weight of distearyl pentaerythritol diphosphite is blended with 100 parts by weight of the polyolefin resin. Stuff. 9. 0.01 to 0.5 of bis (2,4-di-t-butyl-phenyl) pentaerythritol-di-phosphite is added to 100 parts by weight of the polyolefin resin.
The polyolefin resin composition according to claim 3, wherein the polyolefin resin composition is blended in an amount of 0 part by weight. 10. The polyolefin resin composition according to claim 5, wherein 0.01 to 5.0 parts by weight of metal soap is mixed with 100 parts by weight of the polyolefin resin. 11. The metal soap is lithium, magnesium,
The polyolefin resin composition according to any one of claims 5 to 10, which is a fatty acid metal salt of either calcium or zinc. 12. The polyolefin resin composition according to claim 5, wherein the metal soap is zinc stearate. 13. A polyolefin film obtained by molding the polyolefin resin composition according to any one of claims 1 to 12.