JPH1129664A - Radiation-resistant polyolefin composition - Google Patents

Abstract

(57) [Abstract] [Problem] To provide a laminate with the most efficient strength enhancement while minimizing cost increase while maintaining excellent properties such as easy incineration and recycling of paper material. I do. A radiation-resistant polyolefin composition comprising a polyolefin containing at least a hindered phenol compound and a phosphite.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polyolefin composition which can withstand radiation. In particular, the present invention solves the problem of odor caused by deterioration of polyolefin, which is a problem after irradiation of a polyolefin molded product.

[0002]

2. Description of the Related Art Conventionally, irradiation of a polyolefin composition with radiation has been used as a sterilization method in the medical and food packaging fields. In recent years, adhesives utilizing curing by radiation have been proposed in the field of laminating polyolefin films.

When a laminated composite film is produced by laminating a polyolefin film such as a polypropylene film or a polyethylene film, it takes a long time for the adhesive to cure after lamination if a conventional adhesive is used. Is required. In order to solve this problem, a radiation-curable adhesive has recently been used. This radiation-curable adhesive uses a prepolymer having a substituent having a radical polymerizable unsaturated bond in the molecule, so that after irradiation,
It cures immediately and eliminates the need for heat aging, thereby shortening the time required for the laminating step.

However, irradiation of such a polyolefin composition with radiation has many problems such as remarkable deterioration of the polyolefin, decomposition odor, generation of cracks, yellowing and an increase in low molecular weight eluting components.

Therefore, many studies have been made on polyolefin compositions to which various additives such as antioxidants and light stabilizers have been added in order to prevent deterioration of the polyolefins due to radiation irradiation. Various reports have been made on the mechanism and its synergistic effects.

[0006]

As means for preventing deterioration of polyolefin due to irradiation with radiation, Japanese Patent Application Laid-Open No. 58-103541 and the like have been disclosed. We handle
Few have dealt with the problem of odor after irradiation. In addition, the problem of odor generated by irradiation during processing and sterilization becomes a serious problem when the product is used for medical treatment, especially for food use.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a polyolefin composition in which the problem of odor is improved in addition to the above problems generated after irradiation. .

[0008]

Means for Solving the Problems As a result of repeated studies on these problems, the present inventors have found that a polyolefin composition obtained by adding a hindered phenol compound, a phosphite and a polymer type hindered amine compound to a polyolefin is obtained. Degradation of polyolefin by irradiation,
The present inventors have found that the present invention is effective in preventing coloring, and has a great effect in reducing odor after radiation irradiation, and completed the present invention.

The invention of claim 1 is characterized in that the polyolefin contains at least a hindered phenol compound represented by the general formula (4) and a phosphite represented by the general formula (5). Radiation-resistant polyolefin composition (R ¹ and R ^{2 in the} general formula (Chem. 4) represent an alkyl group or a hydrogen atom, R ³ represents an alkyl group, and R ⁴ and R ⁵ in the general formula (Chem. 5) represent An alkyl group and a hydrogen atom, respectively).

[0010]

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[0011]

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According to a second aspect of the present invention, there is provided a radiation-resistant polyolefin composition characterized in that a high molecular weight hindered amine compound represented by the general formula (6) is added to the polyolefin composition according to the first aspect. (M in the general formula (Formula 6) is a positive number of 3 to 8, R ⁶ is an alkyl group,
R ⁷ represents an alkyl group or a hydrogen atom).

[0013]

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According to a third aspect of the present invention, the hindered phenolic compound according to the first aspect is represented by the general formula (Formula 4), and is 0.01 to 0.1% by weight based on the polyolefin.
A radiation-resistant polyolefin composition characterized by being added. The invention of claim 4 is characterized in that the phosphite shown in claim 1 is represented by the general formula (5), and 1.5 to 10 parts by weight is added to 1 part by weight of the hindered phenol compound. It is a polyolefin composition. The invention of claim 5 is characterized in that the polymer type hindered amine compound represented by claim 2 is represented by the general formula (Formula 6), and is added in an amount of 0.02 to 0.8% by weight based on the polyolefin. Radiation-resistant polyolefin composition.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION As the polyolefin used in the present invention, a homopolymer of α-olefin such as ethylene, propylene, 1-butene, 1-pentene, a copolymer thereof, or a copolymer containing these as a main component Copolymers with other monomers, or mixtures thereof, may be mentioned. Other monomers include unsaturated organic acids such as acrylic acid, maleic anhydride and methyl methacrylate, and vinyl silane compounds such as vinyl methoxy silane.

A preferred example of the hindered phenol compound used in the present invention is octadecyl-3-
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentadecyl-3- (3-te
rt-butyl-5-methyl-4-hydroxyphenyl)
And propionate.

Preferred examples of the phosphite used in the present invention include tris (2,4-di-tert-butylphenyl) phosphite, tris (2-tert-butylphenyl) phosphite, and tris (2-tert-butyl). -4-methylphenyl) phosphite and the like.

Preferred examples of the hindered amine compound used in the present invention include poly [｛6- (1,1,3,3).
3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl {(2,2,6,6-tetramethyl-piperidyl) imino {hexamethylene} (2
2,6,6-tetramethyl-piperidyl) imino}],
Poly [{6- (1,1,3-trimethylpentyl) amino-1,3,5-triazine-2,4-diyl} (N
-Methyl-2,2,6,6-tetramethyl-piperidyl) imino {octamethylene} (N-methyl-2,2,
6,6-tetramethyl-piperidyl) imino}].

The addition amount of the hindered phenolic compound represented by the general formula (Chemical Formula 1) is more preferably from 0.02 to
It is 0.06% by weight, and the addition of 0.01% by weight or less has little effect of reducing odor, and the addition of 0.1% by weight or more causes yellowing after irradiation. When the weight of the phosphite represented by the general formula (Chemical Formula 2) is equal to or less than that of the phenolic phenolic compound, the odor reducing ability is significantly impaired. It is preferably at least 5 equivalents to the phenolic compound.

In the hindered phenolic compound represented by the general formula (1), R ¹ and R ² are tertiary butyl groups, and R ³ is an octadecyl group after irradiation. The phosphite represented by the general formula (Chemical Formula 2) has a tertiary butyl group in which R ⁴ and R ⁵ have a tertiary butyl group of 0.14 wt%, M of the hindered amine compound is 6, R ⁶ is 1,1,
This is a polyolefin composition in which a 3,3-tetramethylbutyl group, R ⁷ has a hydrogen atom and a molecular weight of 2,000 to 3,000 is added in an amount of 0.2% by weight.

It is known that the hindered phenolic compound used in the present invention complements the radicals (R00, etc.) generated in the process of oxidative degradation upon irradiation and produces an antioxidant function by becoming phenoxy radicals. ing.

It is known that the phosphite used in the present invention has an antioxidant function by ionizing a peroxide that easily generates radicals.

It is known that the phosphite used in the present invention has a function of reducing quinone generated by oxidation of a phenolic compound which causes yellowing and regenerating a hydroxyl group.

The present invention prevents the oxidation of the polyolefin after irradiation with these comprehensive functions and improves the odor generated thereby.

The production of the polyolefin composition of the present invention comprises:
The above-mentioned essential components are added to a powdery or pelletized polyolefin, and the mixture is melt-kneaded by a kneading machine such as an extruder.

Generally, each component is added to a powdery polyolefin, mixed in an appropriate mixing device such as a mixer, and then processed into a film by a T-die extruder.
Alternatively, it is practical to process the film once into a pellet and then into a film.

[0027]

Embodiments of the present invention will be described below. <Example> [Production of film] Powder-like base resin polypropylene (MI: 7.0 dg / min, density: 0.91 g /
cm ³ ), the following hindered phenol compound, phosphite and hindered amine compound were added at the ratio shown in Table 1 and mixed by dry blending.
It was formed into a film by a mm-diameter extruder (240 ° C.). This film was subjected to an acceleration voltage of 200 KV and an irradiation dose of 30.
Irradiation was performed under the conditions of Kgy and an oxygen concentration of 30 to 50 ppm.

[Hindered Phenol] Irganox 1076: manufactured by Ciba Special Chemicals Co., Ltd. wherein R ¹ and R ² in the above formula (Chemical Formula 1) are tertiary butyl groups and R ³ is an octadecyl group. [Phosphite] Irgafos 168: Ciba Special Chemicals,
In the above formula (2), R ³ and R ⁴ are tertiary butyl groups. [Hindered amine] Chimasorb 994LD: manufactured by Ciba Special Chemicals Co., Ltd. In the above general formula (Chemical Formula 3), m is 6, R ⁶ is 1,
1,3,3-tetramethylbutyl group wherein R ⁷ is a hydrogen atom.

The evaluation was performed as follows. [Odor measurement] The irradiated film is 5000cm
^The mixture was cut into ² pieces, packed in a glass bottle together with activated carbon to concentrate odor components, and stored at 80 ° C. for 20 hours. Thereafter, only the activated carbon was taken out, and the odor component was extracted with 1 mL of carbon disulfide. The odor was determined by quantifying acid components (acetic acid, propionic acid, butyric acid, valeric acid), which are indicators of the odor due to oxidative deterioration of the polyolefin, by gas column chromatography.

[Evaluation of Yellowing] The yellowing was evaluated by visually observing the appearance of each film after irradiation. Table 1 shows the evaluation results.

[0031]

[Table 1]

<Comparative Example> In Example 1, the following compounds were added to the hindered phenol compound, phosphite and hindered amine compound added to the base resin at the ratios shown in Table 1, and Molding was performed in the same manner as in Example 1, and irradiation was performed in the same manner to evaluate odor. Table 1 shows the results.

[Hindered phenol] Irganox 1010: manufactured by Ciba Special Chemicals, pentaerythryl-tetrakis [3- (3,5-
t-butyl-4-hydroxyphenyl) propionate] Yoshinox 2246G: manufactured by Yoshitomi Pharmaceutical Co., Ltd., 2,2′-methylenebis (4-methyl-6-t-butylphenol) [phosphite] Irgafos 168: manufactured by Ciba Special Chemicals,
In the above formula (2), R ³ is a tertiary butyl group. [Hindered amine] Chimasorb 994LD: manufactured by Ciba Special Chemicals Co., Ltd. In the above general formula (Chemical Formula 3), m is 6, R ⁶ is 1,
1,3,3-tetramethylbutyl group wherein R ⁷ is a hydrogen atom. Tinuvin 622: Ciba Special Chemicals, dimethyl succinate / 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate

As can be seen from the results of the embodiment shown in Table 1,
The polypropylene composition in which Irganox 1076, Irgafos 168, and Chimassorb 994LD are blended in a well-balanced manner has good results in both acid generation amount and yellowing.
Looking at the comparative examples, it can be seen that other combinations cause problems such as an increase in the amount of generated acid and yellowing. Further, even when Irganox 1076 and Irgafos 168 are used, when the weight ratio of Irganox 1076 / Irgafos 168 is 1/1, the amount of acid generated increases even if Irganox 1076 is sufficiently added. If the content of Irganox 1076 is 0.08% by weight or more, yellowing proceeds.

[0035]

The polyolefin composition of the present invention contains a hindered phenol, a phosphite and a high molecular weight type hindered amine in a well-balanced manner, thereby suppressing the oxidative deterioration of the polyolefin film due to the irradiation, oxidizing odor after irradiation and yellowing. We can greatly improve strangeness. Therefore, when radiation is applied in the conventional sterilization and product processing steps, it is very effective especially in a field where the odor of the product is a problem.

Claims (5)

[Claims] 1. A radiation-resistant polyolefin composition comprising at least a hindered phenolic compound represented by the general formula (1) and a phosphite represented by the general formula (2). R ¹ and R ^{2 in the} general formula (Chemical Formula 1) represent an alkyl group or a hydrogen atom, R ³ represents an alkyl group, and R ¹ and R ² in the general formula (Chemical Formula 2)
⁴ and R ⁵ represent an alkyl group and a hydrogen atom, respectively). Embedded image Embedded image 2. A radiation-resistant polyolefin composition comprising a polyolefin composition represented by the general formula (3) and a polymer type hindered amine compound represented by the general formula (3). 3) m inside is 3 ~
R ⁶ represents an alkyl group, and R ⁷ represents an alkyl group or a hydrogen atom. Embedded image 3. The radiation-resistant compound according to claim 1, wherein the hindered phenolic compound is represented by the general formula (1) and is added in an amount of 0.01 to 0.1% by weight based on the polyolefin. Polyolefin composition. 4. The phosphite according to claim 1 is represented by the following general formula (2) and is characterized in that 1.5 to 10 parts by weight is added to 1 part by weight of a hindered phenol compound. Polyolefin composition. 5. A polymer type hindered amine compound represented by the general formula (3), wherein 0.02 to 0.8% by weight of polyolefin is added. Radiation-induced polyolefin composition.