JPH1149890A - Stabilizer composition for polyethylene and polyethylene composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stabilizer composition that can produce molded product of a metallocene straight-chain low-density polyethylene that is excellent in bleeding resistance and in deodorant effects as well as heat resistance, thermal discoloration resistance and provide a metallocene polyethylene composition containing the same. SOLUTION: This objective stabilizer composition for metallocene polyethylene contains (A) a phenolic stabilizer of 1,3,5-tris(4-hydroxy-3,5-t-butylbenzyl)-s- triazine-2,4,6-(1H,3H,5H)-trione and (B) a phosphorus stabilizer of tris(2,4-di-t- butylphenyl) phosphite and/or bis(2,6-di-t-butyl-4-methylphenyl) pentaerythritol disphosphite at a weight ratio [(A)/(B)] of 10/1-1/10. The objective metallocene polyethylene composition contains (C) 100 pts.wt. of the metallocene polyethylene, (A) 0.01-0.60 pt.wt. of a phenolic stabilizer and (B) 0.01-0.60 pt.wt. a phosphorus stabilizer. The component C is preferably a straight-chain low density polyethylene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stabilizer composition for metallocene polyethylene and a metallocene polyethylene composition containing the stabilizer composition, and more particularly, to a composition having excellent heat resistance and heat discoloration resistance and bleed resistance. The present invention relates to a stabilizer composition capable of providing a metallocene-based polyethylene molded article excellent in heat resistance and preventing odor generation, particularly a linear low-density polyethylene molded article, and a metallocene-based polyethylene composition containing the stabilizer composition.

[0002]

BACKGROUND OF THE INVENTION Conventionally, in order to improve the heat resistance and heat discoloration resistance of a linear low density polyethylene molded product prepared using a Ziegler type olefin polymerization catalyst, the Ziegler type linear low density polyethylene is used. Polyethylene, for example, n-octadecyl-3- (4'-hydroxy-3 ', 5'-di-t-butylphenol) propionate, which is a phenolic stabilizer (antioxidant), and a phosphorus stabilizer (antioxidant) ), Which is tris (2,4-di-t-butylphenyl) phosphite.

As in the case of the Ziegler-based linear low-density polyethylene, n-octadecyl-3- (4 ′) is added to the linear low-density polyethylene prepared using a so-called metallocene olefin polymerization catalyst. -Hydroxy-3 ', 5'
When -di-t-butylphenol) propionate and tris (2,4-di-t-butylphenyl) phosphite are blended, the resulting molded article of the polyethylene composition has extremely poor heat discoloration resistance.

The inventors of the present invention have studied various formulations of stabilizers that can provide a metallocene-based linear low-density polyethylene molded article having excellent heat resistance and heat discoloration resistance. Although there were combinations of stabilizers capable of producing molded articles having excellent discoloration properties, problems such as generation of an odor or bleeding out of the stabilizer newly occurred.

Therefore, a stabilizer composition which is excellent in heat resistance and heat discoloration resistance, is excellent in bleeding resistance, and can provide a polyethylene molded article such as a metallocene linear low-density polyethylene in which odor generation is prevented, And the appearance of metallocene-based polyethylene compositions containing such stabilizer compositions are desired.

[0006]

The object of the present invention is to stably produce a polyethylene molded article such as a metallocene linear low-density polyethylene having excellent heat resistance and heat discoloration resistance, excellent bleeding resistance and preventing odor generation. And a metallocene-based polyethylene composition containing the stabilizer composition.

[0007]

SUMMARY OF THE INVENTION The stabilizer composition for metallocene polyethylene according to the present invention comprises 1,3,5-tris (4-hydroxy-3,5-
Di-t-butylbenzyl) -s-triazine-2,4,6- (1H.3
H.5H) -Trione-based phenolic stabilizer (A)
And phosphorus comprising tris (2,4-di-t-butylphenyl) phosphite (B1) and / or bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite (B2) Weight ratio [(A)
/ (B)] in a ratio of 10/1 to 1/10.

The metallocene polyethylene composition according to the present invention is a metallocene polyethylene (C) 100 prepared using a metallocene olefin polymerization catalyst.
Phenol consisting of parts by weight and 1,3,5-tris (4-hydroxy-3,5-di-t-butylbenzyl) -s-triazine-2,4,6- (1H.3H.5H) -trione System stabilizer (A) 0.01 to
0.60 parts by weight of tris (2,4-di-t-butylphenyl) phosphite (B1) and / or bis (2,6-diphenyl)
-t-butyl-4-methylphenyl) pentaerythritol
-Phosphorus stabilizer (B) consisting of diphosphite (B2)
And 0.01 to 0.60 parts by weight.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The stabilizer composition for metallocene polyethylene according to the present invention and the metallocene polyethylene composition using the stabilizer composition will be specifically described below.

[0010] The stabilizer composition for metallocene polyethylene according to the present invention comprises a specific phenolic stabilizer (A) and a specific phosphorus-based stabilizer (B). The metallocene-based polyethylene composition according to the present invention comprises a metallocene-based polyethylene (C) and a specific phenol-based stabilizer (A).
And a specific phosphorus-based stabilizer (B).

Phenol stabilizer (A) The phenol stabilizer (A) used in the present invention comprises 1,3,
5-tris (4-hydroxy-3,5-di-t-butylbenzyl)
-s- Triazine-2,4,6- (1H.3H.5H) -trione [= 1,3,
5-tris (3,5-di-t-butyl-4-hydroxybenzyl)
Isocyanurate] and is represented by the following formula.

[0012]

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The phenolic stabilizer (A) has a weight ratio [(A) / (B)] of the phenolic stabilizer (A) to the phosphorus-based stabilizer (B) of 10/1 to 1/10, Preferably 4/1
Used in an amount in the range of 1 to 4 and 0.01 to 100 parts by weight of the metallocene-based polyethylene (C).
It is used in an amount of 0.60 parts by weight, preferably 0.02 to 0.40 parts by weight.

Phosphorus stabilizer (B) The phosphorus stabilizer (B) used in the present invention is tris (2,
4-di-t-butylphenyl) phosphite (B1) and bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite (B2), each of which is represented by the following formula. These compounds can be used alone or in combination.

[0015]

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[0016]

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The phosphorus-based stabilizer (B) has a weight ratio of the phenol-based stabilizer (A) to the phosphorus-based stabilizer (B) [(A) /
(B)], 10/1 to 1/10, preferably 4/1 to 1 /
4, and used in an amount of 0.01 to 0.60 with respect to 100 parts by weight of the metallocene-based polyethylene (C).
It is used in an amount of 0.02 to 0.40 parts by weight, preferably 0.02 to 0.40 parts by weight.

Metallocene polyethylene (C) Metallocene polyethylene (C) used in the present invention
Any polyethylene can be used as long as it is prepared using a conventionally known metallocene olefin polymerization catalyst. In the present invention, the metallocene linear low density polyethylene (ML-LDP) is used.
E) is preferred.

The density (ASTMD 1505) of the metallocene linear low density polyethylene (ML-LDPE) is preferably 0.890 to 0.940 g / m ³ , more preferably 0.905 to 0.930 g. / M ³ . In addition, the melt flow rate (MFR; AS
TM D 1238, 190 ° C, 2.16 kg load) is preferably 0.0
5 to 30 g / 10 min, more preferably 0.5 to 20 g /
It is desirable to be within the range of 10 minutes. Such polyethylene (C) can be used alone or in combination of two or more. Further, a high-pressure low-density polyethylene or a polyethylene obtained by using a Ziegler catalyst can be mixed and used.

Stabilizer Composition The stabilizer composition for metallocene-based polyethylene according to the present invention is a mixture of the above-mentioned phenol-based stabilizer (A) and phosphorus-based stabilizer (B).

Metallocene Polyethylene Composition When preparing the metallocene polyethylene composition according to the present invention, a mixture of the above stabilizers can be blended with the metallocene polyethylene (C). A) and the phosphorus-based stabilizer (B) can be individually compounded.

The metallocene polyethylene composition according to the present invention comprises, in addition to the components (A), (B) and (C),
Other resins, and conventionally known additives blended in a general polyethylene composition, for example, inorganic or organic fillers, inorganic or organic pigments, antistatic agents, additives such as lubricants, do not impair the object of the present invention. It may be contained in the range.

[0023]

The metallocene-based stabilizer composition according to the present invention is excellent in heat resistance and heat discoloration resistance, and is excellent in bleeding resistance and prevents odor generation, such as metallocene linear low-density polyethylene. A polyethylene molded article can be provided.

Further, the metallocene-based polyethylene composition according to the present invention includes the metallocene-based polyethylene stabilizer composition according to the present invention, which has the above-mentioned effects.
A polyethylene molded product such as a metallocene linear low-density polyethylene having excellent heat resistance and heat discoloration resistance, excellent bleeding resistance, and preventing odor generation can be provided. Therefore, the metallocene-based polyethylene composition according to the present invention is suitable as a raw material for packaging materials for food packaging, for example, films, injection molded products, blow molded products and the like.

[0025]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

The metallocene polyethylenes and stabilizers used in Examples and Comparative Examples are as follows. ○ Metallocene polyethylene pellet-shaped linear low-density polyethylene (L-LDP)
E) Density (ASTM D 1505): 0.920 g / cm ³ MFR (ASTM D 1238, 190 ° C, 2.16 kg load): 4.1 g
/ 10 min ○ Phenol stabilizer (1) 1,3,5-tris (4-hydroxy-3,5-di-t-butylbenzyl) -s-triazine-2,4,6- (1H.3H. (A1) (2) n-octadecyl-3- (4'-hydroxy-3 ', 5'-di-t-
(Butylphenyl) propionate; (A2)

[0027]

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(3) Tetrakis- [methylene-3- (3,5-di-t-
(Butyl-4-hydroxyphenyl) propionate] methane; (A3)

[0029]

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○ Phosphorus stabilizer (1) Tris (2,4-di-t-butylphenyl) phosphite; (B1) (2) Bis (2,6-di-t-butyl-4-methylphenyl) Pentaerythritol-diphosphite; (B2) (3) tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene-diphosphite; (B3)

[0031]

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The evaluations of the stabilizer compositions and metallocene-based polyethylene compositions obtained in Examples and Comparative Examples were as follows.
The following physical property test was performed.

(1) Heat resistance The MFR (AS) of pellets obtained by repeatedly pelletizing three times at a resin temperature of the polyethylene composition of 280 ° C.
TM D 1238, 190 ° C, 2.16 kg load) and the MFR of the pellets obtained by repeated pelletization five times were measured, and the difference (ΔMFR) from the MFR of the pellet before repeated pelletization was determined. The sex was evaluated. The smaller the ΔMFR, the better the heat resistance.

Three-step evaluation ○: ΔMFR ≦ 0.5 (g) after repeating pelletization three times
/ 10 min), and after repeated pelletization 5 times ΔMFR
≦ 1.1 (g / 10 minutes) Δ: After repeating pelletization three times 0.5 <ΔMFR ≦ 1.0.
0 (g / 10 minutes) and after 5 times of pelletizing
1.1 <ΔMFR ≦ 2.0 (g / 10 min) ×: ΔMFR> 1.0 (g) after repeating pelletization three times
/ 10 min) and after repeating pelletization 5 times ΔMFR
> 2.0 (g / 10 minutes)

(2) Heat-resistant discoloration (a) A cast film made of a polyethylene composition and having a thickness of 30 μm is placed in an oven at 80 ° C. and 100% RH and left for 2 weeks to check whether the cast film is discolored. And the heat discoloration resistance was evaluated.

Three-level evaluation ○: no discoloration Δ: slight discoloration ×: apparent discoloration

(B) After filling the exhaust gas of a diesel vehicle into a plastic bag, a cast film made of a polyethylene composition and having a thickness of 30 μm is put into the plastic bag, and the film is added at room temperature.
The cast film was allowed to stand for a time, and the discoloration of the cast film was visually observed to evaluate heat discoloration resistance.

Three-level evaluation ○: no discoloration Δ: faint discoloration ×: clear discoloration

(3) Odor A glass bottle having a capacity of 360 ml was filled with 150 g of the pellet-shaped polyethylene composition and natural water heated to 85 ° C., and then capped with aluminum foil, and this was kept at room temperature (23 ° C.) for 9 days. I left it. Thereafter, selected panelists (several persons) included the natural water in their mouths and evaluated whether or not there was an odor.

Three-level evaluation ○: no odor △: slight odor ×: odor

(4) Bleed Resistance A cast film made of a polyethylene composition and having a thickness of 30 μm was left in an air oven at 40 ° C. for one week, and evaluated whether or not the film surface bleed out white.

Three-step evaluation of bleeding resistance : No bleed-out △: Slightly white with bleed-out ×: White with bleed-out

[0043]

Example 1 100 parts by weight of the linear low-density polyethylene and a phenolic stabilizer [(A1) = (A)] 0.0
5 parts by weight and 0.05 part by weight of the phosphorus-based stabilizer (B1)
The mixture was mixed using a Henschel mixer, and the mixture was pelletized with an extruder.

Using the pellets of the obtained polyethylene composition, the heat resistance and the effect of preventing the generation of odor were evaluated according to the above method. The pellets obtained as described above were molded by a casting method under the following molding conditions to obtain a film having a thickness of 30 μm and a width of 400 mm. [Molding conditions] Molding machine: Uni-melt 65 mmφ cast molding machine manufactured by Toshiba Machine Co., Ltd. Die diameter: 500 mm Molding temperature: cylinder 180 ° C, die 220 ° C Take-off speed: 20 m / min Heat-resistant discoloration of the film obtained as described above. The properties and bleed resistance were evaluated according to the above-mentioned methods.

The results are shown in Table 1.

[0046]

Examples 2 and 3 and Comparative Examples 1 to 5 The procedure of Example 1 was repeated except that the amount of the stabilizer shown in Table 1 was changed to the amount shown in Table 1.

The results are shown in Table 1.

[0048]

Comparative Example 6 As shown in Table 1, the heat resistance and the effect of preventing the generation of odor were evaluated in accordance with the above-mentioned method using only pellet-shaped linear low-density polyethylene without adding a stabilizer. At the same time, the heat discoloration resistance and bleed resistance of the film obtained in the same manner as in Example 1 were evaluated in accordance with the above method.

The results are shown in Table 1.

[0050]

[Table 1]

Claims (3)

[Claims] (1) 1,3,5-tris (4-hydroxy-3,5-di-t-
Butylbenzyl) -s-triazine-2,4,6- (1H.3H.5H)-
Phenolic stabilizer (A) composed of trione and tris (2,4-di-t-butylphenyl) phosphite (B)
1) and / or bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite (B
Weight ratio [(A) /
(B)], in a ratio of 10/1 to 1/10. 2. 100 parts by weight of a metallocene-based polyethylene (C) prepared using a metallocene-based olefin polymerization catalyst, and 1,3,5-tris (4-hydroxy-3,5-di-t-butylbenzyl) ) -S-triazine-2,4,6- (1H.3H.5H) -trione (A) 0.01 to 0.60 parts by weight of a phenolic stabilizer, and tris (2,4-di-t -Butylphenyl) phosphite (B
1) and / or bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite (B
A metallocene-based polyethylene composition comprising 0.01 to 0.60 parts by weight of a phosphorus-based stabilizer (B) comprising 2). 3. The metallocene polyethylene composition according to claim 2, wherein said metallocene polyethylene (C) is a linear low density polyethylene.