JPH08188678A - Disintegrable polyolefin composition - Google Patents

Abstract

PURPOSE: To obtain a disintegrable polyolefin compsn. which gives a molding quickly degradable by thermal oxidation by compounding a polyolefin with specified amts. of specific compds. CONSTITUTION: This compsn. is prepd. by compounding 100 pts.wt. polyolefin (e.g. a crystalline PP) with 0.01-1 pt.wt., pref. 0.05-0.5 pt.wt., copper carboxylate (e.g. copper 2-ethylhexanoate) and 0.01-1 pt.wt., pref. 0.05-0.5 pt.wt., hydroxylphenylbenzotriazole compd. [e.g. 2-(2'-hydroxyl-5'-t-octylphenyl) benzotriazole]. The compsn. gives a molding which can be easily disposed of after being used, thus contributing to pollution control.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to disintegrating polyolefin compositions. More specifically, it relates to a disintegrating polyolefin composition in which the thermal oxidative deterioration of polyolefin in a natural environment is promoted.

[0002]

2. Description of the Related Art Generally, polyolefin is relatively inexpensive and has excellent mechanical properties, thermal properties and chemical properties.
For example, it is used in large quantities in the manufacture of various molded products such as injection molded products such as containers and sundries, hollow molded products, films for packaging, sheets, ropes, strings, and fibers. However,
With respect to the disposal of used products, these properties act in reverse, and they are not easily destroyed, and even if they are left in a natural environment, they are not easily broken down. With the large consumption of plastics, the treatment of these wastes is becoming a big social problem. Therefore, in recent years, a method of photodegrading, oxidatively degrading, or degrading biodegradable by microorganisms in soil has become considered,
Photodegradable plastics and biodegradable plastics have already been put to practical use.

However, only by the photolysis method, the portions which are not exposed to light in the natural environment, that is, the shaded portions, the underlaid portions, the buried portions and the like remain without being decomposed. For example, when using these photo-degradable plastics to produce binding cords for agriculture and using them as branch cords for fixing fruit trees or binding cords for rice reapers, decomposition is significantly promoted in the parts exposed to sunlight. However, the shaded area and the area covered with soil are slow to decompose and the intended purpose cannot be achieved. In addition, the part that is not buried in the ground under the natural environment remains without being decomposed only by the biodegradation method. For example, when an agricultural mulch film is manufactured using these biodegradable plastics and used for heat retention and weeding of cultivated land, the part buried in the ground is significantly promoted to decompose, but the part not buried in the ground. Is slow to decompose and cannot achieve its intended purpose. For this reason, an agricultural mulch film having both biodegradability and photodegradability is conceivable in order to promote the decomposition of the part that is not buried in the ground, but there is a problem in that the cost increases.

For this reason, the present applicant has selected a polyolefin resin for the purpose of accelerating the decomposition and degradation of the polyolefin in the natural environment without depending on only photolysis or biodegradation.
(1) A metal salt of benzoic acid, (2) A method for promoting the decomposition of a polyolefin, which comprises adding at least one of a combination of benzoic acid and a higher fatty acid metal salt.
-75645, which was previously proposed, describes that a stabilizer, a pigment, a filler, a different resin, etc. added to a polyolefin resin can be used in combination with the decomposition accelerator of the present invention. On the other hand, JP-A-3-271208 discloses that (a) at least one kind of metal salt compound particles capable of eluting aqua ions of silver and / or copper having excellent antibacterial and antifungal performance,
(B) at least one kind of resin discoloration preventing agent coated on the metal salt compound particles, and (c) waxes further coated on a composite of the metal salt compound particles and the resin discoloration preventing agent. An antibacterial resin composition containing a masterbatch of metal salt compound particles mainly composed of at least one kind is proposed, and in the publication, a silver salt of an inorganic acid as a silver salt compound and higher fatty acids such as silver stearate and silver behenate. , A copper salt of an inorganic acid as a copper salt compound, and a benzotriazole-based ultraviolet absorber as a discoloration inhibitor for resins.

[0005]

However, the method for promoting the decomposition of polyolefins proposed in the above-mentioned Japanese Patent Laid-Open No. Sho 48-75645 is not yet sufficiently satisfactory although the decomposition and deterioration are accelerated, and the method is stable in that publication. There is no description or suggestion that the thermal oxidative deterioration is further promoted by the combined use of a benzotriazole-based UV absorber as an agent with copper carboxylate. Further, in the antibacterial resin composition proposed in JP-A-3-271208, a polyolefin is used as a resin, a copper salt of a higher fatty acid is used as a copper salt compound, and a benzotriazole-based ultraviolet absorber is used as a discoloration inhibitor for a resin. There is no description or suggestion that the oxidative deterioration of the antibacterial polyolefin composition is accelerated.

The present inventor has conducted extensive studies to obtain a composition that solves the above-mentioned problems relating to the polyolefin composition, that is, a polyolefin composition having accelerated thermal oxidative deterioration. As a result, the present inventor has found that a composition obtained by blending a specific amount of copper carboxylate and a specific amount of a hydroxyphenylbenzotriazole-based compound in a polyolefin can solve the above-mentioned drawbacks of the polyolefin composition. The present invention has been completed based on the above. As is clear from the above description, it is an object of the present invention to provide a disintegrating polyolefin composition in which the thermal oxidative deterioration of a molded article is accelerated.

[0007]

The present invention has the following constitution. With respect to 100 parts by weight of polyolefin, 0.01 to 1 part by weight of a copper carboxylate (hereinafter referred to as compound A) and a hydroxyphenylbenzotriazole-based compound (hereinafter, referred to as
It is called compound B. ) 0.01 to 1 part by weight of a disintegrating polyolefin composition.

The polyolefin used in the present invention is a crystalline homopolymer of α-olefin such as ethylene, propylene, butene-1, pentene-1, 4-methyl-pentene-1, hexene-1, octene-1, and the like. Crystalline, low crystalline or amorphous random copolymer or crystalline block copolymer of two or more α-olefins, amorphous ethylene-propylene-nonconjugated diene terpolymer, amorphous ethylene -A polyolefin such as a cyclic alkene copolymer (for example, amorphous ethylene-tetracyclododecene copolymer), a copolymer of the above-mentioned α-olefin and vinyl acetate or an acrylic ester, a ken of the copolymer Compound, these α
-A copolymer of an olefin and an unsaturated silane compound, a copolymer of these α-olefin and an unsaturated carboxylic acid or an anhydride thereof, a reaction product of the copolymer and a metal ion compound, the above-mentioned polyolefin Examples thereof include modified polyolefins modified with unsaturated carboxylic acids or their derivatives, and silane-modified polyolefins modified with the above-mentioned polyolefins with unsaturated silane compounds. These polyolefins may be used alone or in combination of two or more. It is also possible to use a mixture of polyolefins.

In addition to the above-mentioned polyolefins, various synthetic rubbers (for example, polybutadiene, polyisoprene, polychloroprene, chlorinated polyethylene, chlorinated polypropylene, fluororubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, styrene-butadiene- rubber).
Styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-butylene-
Styrene block copolymer, styrene-propylene-butylene-styrene block copolymer, ethylene-ethylene-
Butylene-ethylene block copolymer, ethylene-propylene-butylene-ethylene block copolymer, etc.) or thermoplastic synthetic resin (eg polystyrene, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, polyamide, polyethylene terephthalate , Polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate, polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, fluororesin, petroleum resin (for example, C ₅ petroleum resin, hydrogenated C ₅ series petroleum resin, C ₉ series petroleum resin, hydrogenated C ₉ series petroleum resin, C ₅ -C ₉ copolymerized petroleum resin, hydrogenated C ₅ -C ₉ copolymerized petroleum resin, acid modified C ₉
Softening point of petroleum resin such as 80-200 ℃), DC
PD resin (for example, cyclopentadiene-based petroleum resin, hydrogenated cyclopentadiene-based petroleum resin, cyclopentadiene
-C ₅ copolymerized petroleum resin, hydrogenated cyclopentadiene-C ₅ copolymerized petroleum resin, cyclopentadiene-C ₉ copolymerized petroleum resin,
Softening point of hydrogenated cyclopentadiene-C ₉ copolymerized petroleum resin, cyclopentadiene-C ₅ -C ₉ copolymerized petroleum resin, hydrogenated cyclopentadiene-C ₅ -C ₉ copolymerized petroleum resin, etc.
DCPD resin) and the like can also be mixed and used.
Crystalline propylene homopolymer, crystalline propylene copolymer containing 70% by weight or more of propylene component, crystalline ethylene-propylene random copolymer, crystalline ethylene-propylene block copolymer, crystalline propylene- Butene-1 random copolymer, crystalline ethylene-propylene-butene-1 terpolymer, crystalline propylene-hexene-butene-1 terpolymer, and mixtures of two or more thereof are particularly preferably used. .

The compound A used in the present invention is copper acetate, copper n-propionate, copper n-butyrate, copper n-valerate, copper n-hexanoate, copper n-octanoate, copper 2-ethylhexanoate. , N-
Copper decanoate, copper laurate, copper myristate, copper palmitate, copper stearate, copper oleate, copper linoleate, copper linolenate, copper behenate, copper erucate, copper lignocerate, copper serotiate, montanic acid. Fatty acid copper such as copper, copper triphenylacetate, copper oxalate, copper malonate, copper succinate, copper glutarate, copper aliphatic dicarboxylate such as copper adipate, copper naphthenate, copper benzoate, o-toluic acid Copper, copper m-toluate, copper p-toluate, copper pt-butylbenzoate, copper o-methoxybenzoate, copper m-methoxybenzoate, copper aniseate, copper phthalate, copper isophthalate, copper terephthalate Aromatic carboxylate copper, copper lactate, copper citrate, copper 12-hydroxystearate, copper ricinoleate, etc.
Copper hydroxynaphthenate, copper hydroxybenzoate, 3,5-
Examples thereof include copper hydroxy acids such as copper di-t-butyl-4-hydroxybenzoate, and fatty acid copper such as copper 2-ethylhexanoate, copper stearate and copper montanate is particularly preferable. These compounds A may be used alone or in combination of two or more kinds. The compounding ratio of the compound A is 0.01 to 1 part by weight, preferably 0.05 to 0.5 part by weight, based on 100 parts by weight of the polyolefin. When the amount is less than 0.01 parts by weight, the effect of promoting the thermal oxidative deterioration of the polyolefin composition is not sufficiently exerted, and when it exceeds 1 part by weight, a further effect of promoting the thermal oxidative deterioration cannot be expected. Not only is it irrelevant, but it is also uneconomical.

The compound B used in the present invention is 2-
(2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5) '-
Methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-s-butyl-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl)
Benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-
Butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) benzotriazole, 2- (2'-hydroxy-3'-dodecyl-5'-methylphenyl) benzo Triazole, 2- [2'-hydroxy-3 ', 5'-bis (α, α-dimethylbenzyl) phenyl] benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl)
Benzotriazole, 2- [2'-hydroxy-3 '-(3 ", 4",
5 ", 6" -Tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2- (2'-hydroxy-3'-t
-Butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2,2'-methylene -Bis [4- (1,1,3,3-tetramethylbutyl) -6- (2N-benzotriazol-2-yl) phenol], methyl-3- [3-
Examples thereof include t-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propionate-polyethylene glycol condensate and 2- (2-hydroxyphenyl) benzotriazole copolymer. Especially 2-
(2'-Hydroxy-5'-methylphenyl) benzotriazole and 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole are preferred. These compounds B may be used alone or in combination of two or more kinds. The compounding ratio of the compound B is 0.01 to 1 part by weight, preferably 0.05 to 0.5 part by weight, based on 100 parts by weight of the polyolefin. When the amount is less than 0.01 parts by weight, the effect of promoting the thermal oxidative deterioration of the polyolefin composition is not sufficiently exerted, and when it exceeds 1 part by weight, a further effect of promoting the thermal oxidative deterioration cannot be expected. Not only is it irrelevant, but it is also uneconomical.

In the composition of the present invention, various additives which are usually added to polyolefins, for example, phenol-based antioxidants, thioether-based antioxidants, phosphorus-based antioxidants, and light stabilizers (excluding compound B) are included. , Heavy metal deactivator (copper damage inhibitor), clarifying agent, nucleating agent, lubricant, antistatic agent, antifogging agent, antiblocking agent, non-dripping agent, radical generator such as peroxide, flame retardant , Flame retardant aids, pigments, halogen scavengers, dispersants or neutralizing agents such as metal soaps, organic or inorganic antibacterial agents (however, excluding compound A),
Inorganic fillers (eg talc, mica, clay, wollastonite, zeolite, kaolin, bentonite, perlite, diatomaceous earth, asbestos, calcium carbonate,
Magnesium hydroxide, aluminum hydroxide, hydrotalcite, basic aluminum / lithium / hydroxy /
Carbonate hydrate, silicon dioxide, titanium dioxide, zinc oxide, calcium oxide, magnesium oxide,
Zinc sulphide, barium sulphate, magnesium sulphate, calcium silicate, aluminum silicate, glass fiber, potassium titanate, carbon fiber, carbon black, graphite and metal fibers), coupling agents (eg silane-based, titanate-based, boron-based) , An aluminate type, a zircoaluminate type, etc.) or an organic filler (for example, wood flour, pulp, waste paper, synthetic fiber, natural fiber, etc.) surface-treated with a surface treating agent such as It can be used in combination as long as the purpose is not impaired. Further, a polyolefin composition containing no antioxidant is also rapidly decomposed in a natural environment, but since it generally lacks stability during processing and storage, the addition of an antioxidant is essential, and the amount of the mixture is polyolefin. It is 0.01 to 1 part by weight with respect to 100 parts by weight. In the composition of the present invention, the timing and degree of thermal oxidative deterioration can be appropriately adjusted by changing the compounding amounts and compounding ratios of these antioxidants and compound A and compound B.

In the composition of the present invention, a predetermined amount of each of the above-mentioned compound A and compound B and the above-mentioned various additives usually added to a polyolefin is added to a polyolefin by a conventional mixing device such as a Henschel mixer (trade name), a super mixer, Mix using a ribbon blender, Banbury mixer, etc., and melt kneading temperature 150 ℃ ~ 320 ℃, using a normal single-screw extruder, twin-screw extruder, Brabender or roll,
Preferably, it can be obtained by melt-kneading and pelletizing at 180 ° C to 290 ° C. The obtained composition is used for production of a target molded article by various molding methods such as an injection molding method, an extrusion molding method, and a blow molding method.

[0014]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The evaluation methods used in Examples and Comparative Examples were as follows. Thermal oxidative deterioration: Thermal oxidative deterioration was evaluated by an oven life test. That is, the length using the obtained pellet
A test piece with a width of 50 mm, a width of 25 mm, and a thickness of 1 mm was prepared by an injection molding method, and the test piece was placed in a circulating hot air oven adjusted to a temperature of 150 ° C., and the time until the test piece was completely deteriorated (tensile strength was 0 (Time until it becomes) is measured (JIS K 7212
The thermal oxidative deterioration property was evaluated. The material excellent in the acceleration property of thermal oxidative deterioration is one having a small oven life value.

Examples 1 to 10, Comparative Examples 1 to 4 Melt flow rate as a polyolefin (amount of molten resin discharged for 10 minutes when a load of 21.18 N at 230 ° C. is applied; hereinafter abbreviated as MFR) 6.0 g / To 100 parts by weight of unstabilized powdery crystalline propylene homopolymer for 10 minutes, as compound A, copper acetate, copper 2-ethylhexanoate or copper stearate, and as compound B, 2- (2'-hydroxy-
5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole or 2- (2'-hydroxy-3'-dodecyl-5'-methylphenyl) benzotriazole and Put the specified amount of each of the other additives into the Henschel mixer (trade name) at the compounding ratios shown in Table 1 below, stir and mix for 3 minutes, and then calibrate 40
It was melt-kneaded at 200 ° C. with a mm single-screw extruder and pelletized. Further, as Comparative Examples 1 to 4, powdery crystalline propylene homopolymer having an MFR of 6.0 g / 10 min and not being stabilized.
Predetermined amounts of the additives shown in Table 1 below were added to 100 parts by weight, and melt-kneaded according to Examples 1 to 10 to obtain pellets. Using the obtained pellets, thermal oxidative deterioration was evaluated by the above test method. The results are shown in Table 1.

Examples 11-20, Comparative Examples 5-8 MFR 4.0 g / 10 min as a polyolefin 70% by weight of non-stabilized powdery crystalline propylene homopolymer, M
FR 7.0g / 10min unstabilized powdery crystalline ethylene-propylene random copolymer (ethylene content 2.5
20% by weight and melt index (the discharge amount of the molten resin for 10 minutes when a load of 21.18N at 190 ° C. is added; hereinafter abbreviated as MI) 5.0 g / 10 minutes unstabilized powdery form A total of 100 parts by weight of a Ziegler-Natta high density ethylene homopolymer was added to 100 parts by weight of copper montanate, copper oleate or copper adipate as the compound A, and 2- [2'-hydroxy-3 'as the compound B. , 5'-Bis (α, α-dimethylbenzyl) phenyl] benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) benzotriazole or 2- (2'-hydroxy- 4'-octoxyphenyl) benzotriazole and other additives were added to the Henschel mixer (trade name) in the proportions shown in Table 2 below, and the mixture was stirred and mixed for 3 minutes. Melt kneading process at 200 ° C in extruder And pelletized. Also, as Comparative Examples 5 to 8, MFR
Unstabilized powdery crystalline propylene homopolymer 70% by weight of 4.0 g / 10 min, MFR 7.0 g / 10 min unstabilized powdery crystalline ethylene-propylene random copolymer (ethylene 2.5% by weight) 20% by weight and 10% by weight of unstabilized powdered Ziegler-Natta high-density ethylene homopolymer in an amount of 5.0 g / 10 min. A predetermined amount of each of the additives described in 1) was mixed and melt-kneaded according to Examples 11 to 20 to obtain pellets. Using the obtained pellets, thermal oxidative deterioration was evaluated by the above test method. Table 2 shows the results.

Examples 21-30, Comparative Examples 9-12 100 parts by weight of an unstabilized powdery crystalline ethylene-propylene block copolymer (ethylene content 8.5% by weight) as MFR 4.0 g / 10 min as a polyolefin. In addition, copper naphthenate, copper benzoate or copper phthalate as compound A, 2- [2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5 as compound B '-Methylphenyl]
Benzotriazole, 2- (2'-hydroxy-3'-t-butyl-
5'-methylphenyl) -5-chlorobenzotriazole or
Henschel mixer (2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole and other additives in predetermined amounts at the compounding ratios shown in Table 3 below Product name), stir and mix for 3 minutes, then caliber 40
It was melt-kneaded at 200 ° C. with a mm single-screw extruder and pelletized. Further, as Comparative Examples 9 to 12, 100 parts by weight of powdered crystalline ethylene-propylene block copolymer (ethylene content 8.5% by weight) having an MFR of 4.0 g / 10 min and not being stabilized are shown in Table 3 below. A predetermined amount of each additive was blended and melt-kneaded according to Examples 21 to 30 to obtain pellets. Using the obtained pellets, thermal oxidative deterioration was evaluated by the above test method. The results are shown in Table 3.

Examples 31-40, Comparative Examples 13-16 70% by weight of an unstabilized powdery crystalline propylene homopolymer of MFR 8.0 g / 10 min as a polyolefin, M
FR 7.0 g / 10 min unstabilized powdery crystalline ethylene-propylene-butene-1 terpolymer (ethylene content 2.5% by weight, butene-1 content 4.5% by weight) 5% by weight,
MI 5.0 g / 10 min unstabilized powdery low density ethylene homopolymer 10% by weight and Mooney viscosity ML1 + 4 (100
℃) 25 powdered non-stabilized amorphous ethylene-propylene random copolymer (propylene content 25% by weight)
15% by weight in total of 100 parts by weight, as compound A, copper lactate, copper 12-hydroxystearate or copper 3,5-di-t-butyl-4-hydroxybenzoate, and as compound B 2,2'- Methylene-bis [4- (1,1,3,3-tetramethylbutyl) -6-
(2N-benzotriazol-2-yl) phenol], methyl-3- [3-t-butyl-5- (2H-benzotriazole-2-
))-Hydroxyphenyl] propionate-polyethylene glycol condensate or 2- (2-hydroxyphenyl) benzotriazole copolymer and other additives in predetermined amounts in the proportions shown in Table 4 below. The mixture was placed in a mixer (trade name), stirred and mixed for 3 minutes, and then melt-kneaded at 200 ° C. with a single-screw extruder having a diameter of 40 mm to form pellets. Also, as Comparative Examples 13 to 16, MF
70% by weight of unstabilized powdery crystalline propylene homopolymer having R of 8.0 g / 10 min, unstabilized powdery crystalline ethylene-propylene-butene-13 of MFR of 7.0 g / 10 min Original copolymer (ethylene content 2.5% by weight, butene
-1 content 4.5% by weight) 5% by weight, unstabilized powdery low-density ethylene homopolymer 10% by weight of MI 5.0 g / 10 min, and Mooney viscosity ML1 + 4 (100 ° C) 25 stable Powdered amorphous ethylene-propylene random copolymer (15% by weight of propylene content) which has not been compounded, and 100% by weight in total of the prescribed amounts of the additives shown in Table 4 below. Then, the melt-kneading process was performed according to Examples 31 to 40 to obtain pellets. Using the obtained pellets, thermal oxidative deterioration was evaluated by the above test method. Table 4 shows the results.

The various additives shown in Tables 1 to 4 are as follows. Compound A [1]: Copper acetate Compound A [2]: Copper 2-ethylhexanoate Compound A [3]: Copper stearate Compound A [4]: Copper montanate Compound A [5]: Copper oleate Compound A [ 6]: copper adipate compound A [7]: copper naphthenate compound A [8]: copper benzoate compound A [9]: copper phthalate compound A [10]: copper lactate compound A [11]: 12-hydroxy Copper stearate Compound A [12]: Copper 3,5-di-t-butyl-4-hydroxybenzoate Compound B [1]: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole Compound B [ 2]: 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole Compound B [3]: 2- (2'-hydroxy-3'-dodecyl-5'-
Methylphenyl) benzotriazole compound B [4]: 2- [2'-hydroxy-3 ', 5'-bis (α,
α-Dimethylbenzyl) phenyl] benzotriazole Compound B [5]: 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole Compound B [6]: 2- (2′- Hydroxy-4'-octoxyphenyl) benzotriazole compound B [7]: 2- [2'-hydroxy-3 '-(3 ", 4", 5 ", 6"
-Tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole compound B [8]: 2- (2'-hydroxy-3'-t-butyl-5'-
Methylphenyl) -5-chlorobenzotriazole compound B [9]: 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole compound B [10]: 2, 2'-Methylene-bis [4- (1,1,3,3-tetramethylbutyl) -6- (2N-benzotriazol-2-yl) phenol] Compound B [11]: Methyl-3- [3- Condensation product of t-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propionate-polyethylene glycol Compound B [12]: 2- (2-hydroxyphenyl) benzotriazole copolymer

Phenolic antioxidant 1: 2,6-di-t-butyl-p-cresol Phenolic antioxidant 2: tetrakis [methylene-3-
(3 ', 5'-Di-t-butyl-4'-hydroxyphenyl) propionate] methane phenolic antioxidant 3: 1,3,5-trimethyl-2,4,6-
Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene phenolic antioxidant 4: Tris (3,5-di-t-butyl-
4-Hydroxybenzyl) isocyanurate Phosphorus antioxidant 1: Bis (2,4-di-t-butylphenyl) -pentaerythritol-diphosphite Phosphorus antioxidant 2: Bis (2,6-di-t -Butyl-4-methylphenyl) pentaerythritol-diphosphite thioether antioxidant: dimyristyl thiodipropionate Ag-St: silver stearate Ca-St: calcium stearate

The examples and comparative examples shown in Table 1 are the cases where a crystalline propylene homopolymer was used as the polyolefin. As can be seen from Table 1, Examples 1 to 10 are those in which the compound A and compound B according to the present invention are blended, and Examples 1 to 10 and Comparative example 1 (no compound A and compound B are blended) It can be seen from the comparison of Examples 1 to 10 that the thermal oxidative deterioration is remarkably promoted. Comparison between Comparative Example 2 in which copper benzoate as compound A and calcium stearate as higher fatty acid metal salt (previously proposed by the applicant as JP-A-48-75645) and Examples 1 to 10 are compared. Then, although the thermal oxidative deterioration of Comparative Example 2 is promoted as compared with Comparative Example 1, it is still insufficient. Further, comparing Comparative Example 3 in which the compound B is blended alone with Examples 1 to 10, the thermal oxidative deterioration of Comparative Example 3 is slightly promoted as compared with Comparative Example 1, but it is still insufficient. Further, Comparative Example 4 in which silver stearate was used in place of compound A, compound B as a discoloration preventing agent for resins, and calcium stearate as a wax (the antibacterial resin composition proposed in the above-mentioned JP-A-3-271208). Comparing Examples 1 to 10 with each other, the thermal oxidative deterioration of Comparative Example 4 is about the same as that of Comparative Example 1, and the compound B is added to silver stearate.
It can be seen that the thermal oxidative deterioration is not promoted even when used together.
Therefore, it is apparent that the comparative examples that do not simultaneously satisfy the combination of the two components of the compound A and the compound B according to the present invention do not exhibit the effects of the present invention. That is, it can be said that the thermal oxidative deterioration obtained in the present invention is a unique effect that can be seen only when the compound A and the compound B are used in combination in the present invention.

Tables 2 to 4 show a mixture of a crystalline propylene homopolymer, a crystalline ethylene-propylene random copolymer and a Ziegler-Natta high density ethylene homopolymer as a polyolefin, and a crystalline ethylene-propylene block copolymer, respectively. Polymer or crystalline propylene homopolymer, crystalline ethylene-propylene-butene-1 terpolymer, low density ethylene homopolymer and amorphous ethylene-
A mixture of propylene random copolymers was used, and the effects similar to those described above were confirmed for these.

[0023]

EFFECTS OF THE INVENTION The composition of the present invention is (1) significantly improved in thermal oxidative deterioration of a molded article when it is used as a molded article, as compared with conventionally known polyolefin compositions in which thermal oxidative deterioration is promoted. There is. (2) Since the thermal oxidative deterioration is remarkably promoted, it can be suitably used for applications requiring disintegration in various molding fields (for example, agricultural strings and agricultural mulch films). (3) Disposal of used products is easy and contributes to pollution prevention.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

Claims (1)

[Claims] 1. A disintegrating polyolefin composition comprising 0.01 to 1 part by weight of a copper carboxylate and 0.01 to 1 part by weight of a hydroxyphenylbenzotriazole compound, based on 100 parts by weight of a polyolefin.