JPH07116328B2 - Plastic magnet composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plastic magnet composition. More specifically, the present invention relates to a plastic magnet composition having excellent resistance to thermal oxidative deterioration during practical use.

[Prior Art] Sintered ferrite magnets or samarium-cobalt alloy magnets have been widely used as permanent magnets in the fields of heavy electric power, home appliances, electronic devices, and the like. However, these magnets are mechanically fragile and require secondary processing such as cutting and polishing, which is a serious obstacle in expanding applications in the above fields.

Therefore, for the purpose of solving the above-mentioned problems, a composite material so-called plastic magnet in which magnetic powder is mixed with various synthetic resins has been developed and put into practical use. However, when a polyolefin, especially a propylene-based polymer, is used as the synthetic resin used for the plastic magnet, the propylene-based polymer has tertiary carbon which is easily oxidized, and thus is included in the magnetic powder. Oxidative deterioration is caused catalytically by various metal ions generated, and there arises a problem that the thermal oxidation deterioration resistance (hereinafter referred to as long-term thermal stability) during practical use of the plastic magnet is significantly lowered.

Therefore, a composition (Japanese Patent Laid-Open No. 62-169858) in which a heavy metal deactivator is blended with a plastic magnet is conventionally proposed for the purpose of improving the long-term thermal stability of the plastic magnet using polyolefin. Has been done. Further, for the purpose of stabilizing polypropylene, a composition (JP-A-54-101846) in which a specific calcium phosphonate compound is blended with the polypropylene has been proposed.

[Problems to be Solved by the Invention] However, the above-mentioned Japanese Patent Laid-Open Publication No. Sho.
Although the plastic magnet composition proposed in Japanese Patent Laid-Open No. 62-169858 is considerably improved in long-term thermal stability, it is still not sufficiently satisfactory. In addition, the above-mentioned JP
No. 54-101846, there is no description of blending a specific calcium phosphonate compound in a plastic magnet composition in combination with a heavy metal deactivator, and the combination is a plastic magnet composition. No statement suggesting that it improves long-term thermal stability is found.

The present inventor has conducted extensive studies in order to solve the above-mentioned problems regarding the above-mentioned plastic magnet composition, that is, the problem of long-term thermal stability. As a result, a plastic magnet made of polyolefin and magnetic powder is blended with specific amounts of a phosphonate compound represented by the following general formula [I] (hereinafter referred to as compound A) and a heavy metal deactivator. It was found that the composition can solve the problems of the above-mentioned plastic magnet composition, and the present invention was completed based on this finding.

(However, in the formula, R ₁ is hydrogen or an alkyl group having 1 to 8 carbon atoms, R ₂ is an alkyl group having 1 to 8 carbon atoms, and R ₃ is 1 carbon atom.
To 30 alkyl groups, X is 0 or 1, and n is 1 to 4
Indicates the integers of. ) As is clear from the above description, an object of the present invention is to provide a plastic magnet composition which is excellent in long-term thermal stability of a molded product when the molded product is formed.

[Means for Solving Problems] The present invention has the following configurations.

A phosphonate compound represented by the following general formula [I] (hereinafter referred to as compound A) and a heavy metal per 100 parts by weight of a composition comprising 5 to 20% by weight of polyolefin and 80 to 95% by weight of magnetic powder. 0 for each inactivating agent.
A plastic magnet composition containing 01 to 5 parts by weight.

(However, in the formula, R ₁ is hydrogen or an alkyl group having 1 to 8 carbon atoms, R ₂ is an alkyl group having 1 to 8 carbon atoms, and R ₃ is 1 carbon atom.
To 30 alkyl groups, X is 0 or 1, and n is 1 to 4
Indicates the integers of. 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 these two types. The above α-olefin crystalline, low crystalline or amorphous random copolymer or crystalline block copolymer, amorphous ethylene-propylene-non-conjugated diene terpolymer, the above α-olefin Copolymer with vinyl acetate or acrylic ester, saponified product of the copolymer, copolymer of these α-olefins and unsaturated silane compounds, of these α-olefins and unsaturated carboxylic acids or their anhydrides Copolymers, reaction products of the copolymers with metal ion compounds, and modified polyols obtained by modifying polyolefins with unsaturated carboxylic acids or their derivatives. Fins, polyolefin can be exemplified a modified silane modified polyolefin with an unsaturated silane compound, single use of these polyolefins can of course, also possible to use a mixture of two or more polyolefins. Further, the above-mentioned polyolefin and various synthetic rubbers (for example, polybutadiene, polyisoprene, polychloroprene, chlorinated polyethylene, chlorinated polypropylene, fluororubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, styrene-
Butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-ethylene-butylene-styrene block copolymer, styrene-propylene-butylene-styrene block copolymer, etc.) or thermoplastic synthetic resin (for example, polystyrene,
Styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyvinyl chloride, fluororesin, etc.) can be mixed and used. Crystalline propylene homopolymer, 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-
13-element copolymer, crystalline propylene-hexene-butene-
Particularly preferred are terpolymers and mixtures of two or more thereof.

The magnetic powder used in the present invention includes manganese ferrite, nickel ferrite, zinc ferrite, manganese-zinc ferrite, manganese-zinc-iron ferrite, nickel-zinc ferrite, cobalt-iron ferrite, manganese-magnesium-aluminum ferrite, strontium ferrite. Examples thereof include ferrite-based magnetic powders such as barium ferrite, chromium ferrite, calcium ferrite, lead ferrite, and sodium-lanthanum ferrite, and rare earth cobalt-based magnetic powders such as samarium cobalt, and strontium ferrite and barium ferrite are particularly preferable. The particle size of these magnetic powders is not particularly limited, but is usually 0.5μ to 50μ,
It is preferably 0.5 μ to 10 μ, and most preferably 1 μ to 5 μ. Further, these magnetic powders are surface treatment agents such as silane coupling agents, titanate coupling agents,
When the surface treatment is performed in advance with a known surface treatment agent such as a boron coupling agent, an aluminate coupling agent and a zircoaluminate coupling agent, the compatibility and dispersibility of the magnetic powder with the polyolefin are improved. The magnetic powder which has been surface-treated with a surface-treating agent is improved because the molded product is improved and excellent in moldability is obtained, and the mechanical strength of the molded product when the molded product is formed by using the plastic magnet composition is improved. It is preferable to use. It goes without saying that these magnetic powders are used alone, and two or more kinds of magnetic powders can be used in combination. The compounding ratio of the magnetic powder is 80 with respect to the composition comprising the polyolefin and the magnetic powder.
~ 95% by weight. If the amount is less than 80% by weight, the plastic magnet composition has good moldability, but the magnetic properties are insufficient, and if it exceeds 95% by weight, the moldability is difficult and the mechanical strength of the resulting molded product is low. Is too low to be practical.

The compound A used in the present invention includes calcium- (3,
5-di-t-butyl-4-hydroxybenzyl) phosphonate, calcium- (3,5-di-t-butyl-4)
-Hydroxyphenyl) ethyl-phosphonate, calcium- (3,5-di-t-butyl-4-hydroxyphenyl) propyl-phosphonate, calcium-
(3,5-di-t-butyl-4-hydroxyphenyl) butyl-phosphonate, calcium-bis [O-ethyl- (3-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-methyl- (3,
5-di-t-octyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-ethyl- (3
-Methyl-5-t-butyl-4-hydroxybenzyl)
Phosphonate], calcium-bis [O-ethyl-
(3-Ethyl-5-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-ethyl- (3-i-propyl-5-t-butyl-4-hydroxybenzyl) phosphonate] ], Calcium-bis [O-ethyl- (3-i-butyl-5-t-butyl-4]
-Hydroxybenzyl) phosphonate], calcium-bis [O-ethyl- (3-s-butyl-5-t-butyl-4-hydroxybenzyl) phosphonate],
Calcium-bis [O-ethyl- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-ethyl- (3-t-butyl-5-
t-amyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-ethyl- (3-t-butyl-5-t-octyl-4-hydroxybenzyl) phosphonate], calcium-bis [O] -Ethyl- (3,
5-di-t-amyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-ethyl- (3-
t-amyl-5-t-octyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-ethyl- (3,5-di-t-octyl-4-hydroxybenzyl) phosphonate], calcium -Bis [O-n-
Propyl- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-
n-butyl- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O
-N-pentyl- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-n-hexyl- (3,5-di-t-butyl-4-hydroxy] Benzyl) phosphonate], calcium-
Bis [O-n-octyl- (3,5-di-t-butyl-4
-Hydroxybenzyl) phosphonate], calcium-bis [O-n-nonyl- (3,5-di-t-butyl-
4-hydroxybenzyl) phosphonate], calcium-bis [On-dodecyl- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [On-hexadecyl] -(3,5-di-
t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-n-octadecyl- (3,
5-di-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-n-eicosyl- (3,5-di-t-butyl-4-hydroxybenzyl)]
Phosphonate], calcium-bis [O-n-docosyl- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O-triacontyl- (3,5-di) -T-butyl-4-hydroxybenzyl) phosphonate], calcium-bis [O
-Ethyl- (3,5-di-t-butyl-4-hydroxyphenyl) ethyl-phosphonate], calcium-bis [O-ethyl- (3,5-di-t-butyl-4-hydroxyphenyl) Propyl-phosphonate] and calcium-bis [O-ethyl- (3,5-di-t-butyl-4-hydroxyphenyl) butyl-phosphonate], and the like, and especially calcium-bis [O-ethyl -(3,5-di-t-butyl-4-hydroxybenzyl) phosphonate] is preferred. These phosphonate compounds can be used alone, and two or more phosphonate compounds can be used together. The compound A is blended in an amount of 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of a composition comprising 5 to 20% by weight of polyolefin and 80 to 95% by weight of magnetic powder. If the amount is less than 0.01 parts by weight, the effect of preventing oxidative deterioration of the plastic magnet composition is not sufficiently exerted, and if it exceeds 5 parts by weight, further improvement in the effect of preventing oxidative deterioration cannot be expected and it is practical. Not only is it uneconomical.

As the heavy metal deactivator used in the present invention, benzotriazole, 2,4,6-triamino-1,3,5-triazine,
3,9-Bis [2- (3,5-diamino-2,4,6-triazaphenyl) ethyl] -2,4,8,10-tetraoxaspiro [5,
5] Undecane, ethylenediamine-tetraacetic acid, alkali metal salt of ethylenediamine-tetraacetic acid, N, N'-disalicylidene-ethylenediamine, N, N'-disalicylidene-1,2-propylenediamine, N, N "- Disalicylidene-N'-methyl-dipropylenetriamine, 3-salicyloylamino-1,2,
4-triazole, decamethylene dicarboxylic acid-bis (N'-salicyloyl hydrazide), nickel-bis (1-phenyl-3-methyl-4-decanoyl-5-pyrazolate), 2-ethoxy-2'- Ethyl oxanilide, 5-t-butyl-2-ethoxy-2'-
Ethyl oxanilide, N, N-diethyl-N ', N'-diphenyl oxamide, N, N'-diethyl-N, N'-diphenyl oxamide, oxalic acid-bis (benzylidene hydrazide), thiodipropio Nick acid-bis (benzylidene hydrazide), isophthalic acid-bis (2-phenoxypropionyl hydrazide),
Bis (salicyloylhydrazine), N-salicylidene-
N'-salicyloylhydrazone, N, N'-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, tris [2-t-butyl-4]
-Thio (2'-methyl-4'-hydroxy-5'-t-
Examples include butylphenyl) -5-methylphenyl] phosphite and N, N'-bis [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] oxamide. , Especially 2,4,6-triamino-1,3,5-triazine, 3,9-bis [2- (3,5-diamino-2,4,6-triazaphenyl) ethyl] -2,4, 8,1
0-tetraoxaspiro [5,5] undecane, oxalic acid-bis (benzylidene hydrazide), N, N '
-Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, tris [2-t
-Butyl-4-thio (2'-methyl-4'-hydroxy-5'-butylphenyl) -5-methylphenyl] phosphite and N, N'-bis [2- [3- (3,5-di- −
t-Butyl-4-hydroxyphenyl) propionyloxy] ethyl] oxamide is preferred. It goes without saying that these heavy metal deactivators are used alone, and two or more heavy metal deactivators can be used in combination. The compounding ratio of the heavy metal deactivator is 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of a composition comprising 5 to 20% by weight of polyolefin and 80 to 95% by weight of magnetic powder. is there.
If the amount is less than 0.01 parts by weight, the effect of preventing oxidative deterioration of the plastic magnet composition is not sufficiently exerted, and if it exceeds 5 parts by weight, further improvement in the effect of preventing oxidative deterioration cannot be expected and it is practical. Not only is it uneconomical.

In the composition of the present invention, various additives usually added to polyolefins such as phenol-based, thioether-based, phosphorus-based antioxidants, light stabilizers, clarifiers,
Radical generators such as nucleating agents, lubricants, antistatic agents, antifogging agents, antiblocking agents, non-dripping agents, pigments and peroxides,
Dispersants or neutralizers for metal soaps, inorganic fillers (eg talc, mica, clay, wollastonite, zeolite, asbestos, calcium carbonate, aluminum hydroxide, magnesium hydroxide, silicon dioxide, titanium dioxide, zinc oxide) , Magnesium oxide, zinc sulfide,
Barium sulfate, calcium silicate, aluminum silicate, glass fiber, potassium titanate, carbon fiber, carbon black, graphite, metal fiber, etc. or coupling agent (for example, silane-based, titanate-based, boron-based, aluminate-based, zirco) Said inorganic or organic filler (eg wood flour, pulp, waste paper, synthetic fiber, etc.) which has been surface treated with a surface treating agent such as an aluminate type)
(Natural fibers, etc.) can be used in combination as long as the object of the present invention is not impaired. In particular, when a phenolic antioxidant is used in combination, the effect of preventing oxidative deterioration is synergistically exhibited, and therefore it is preferably used in combination. Examples of phenolic antioxidants are 2,6-diphenyl-4-octadecyloxyphenol and 2,4-bis (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1. , 3,5-Triazine, 2,4,6-tris (3 ', 5'-di-t-butyl-
4'-hydroxybenzylthio) -1,3,5-triazine, 1,1,3-tris (5-t-butyl-4-hydroxy-2-methylphenyl) -butane, bis [3,3-bis ( 4'-hydroxy-3'-t-butylphenyl) butyric acid] ethylene glycol ester, bis [2- (3'-t-butyl-2'-hydroxy-5'-
Methylbenzyl) -6-t-butyl-4-methylphenyl] terephthalate, 3,9-bis [1,1-dimethyl-2-
{Β- (3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-
Tetraoxaspiro [5,5] undecane, 3,9-bis [1,
1-dimethyl-2- {β- (3,5-di-t-butyl-4-
Hydroxyphenyl) propionyloxy} ethyl]-
2,4,8,10-Tetraoxaspiro [5,5] undecane, 3,9
-Bis [1,1-dimethyl-2- {β- (3,5-diphenyl-4-hydroxyphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-Bis [1,1-dimethyl-2- {β- (3,5-dicyclohexyl-4-hydroxyphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5 ] Undecane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl)
Benzene, 1,3,5-tris (3,5-di-t-butyl-4-
Hydroxybenzyl) isocyanurate, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3,5-tris [(3,5-
Di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate and tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-
Hydroxyphenyl) propionate] methane and the like, and particularly 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 1,3,5 -Tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 3,9-bis [1,1
-Dimethyl-2- {β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 1, 3,5-Tris [(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate and tetrakis [methylene-3- (3 ', 5']
-Di-t-butyl-4'-hydroxyphenyl) propionate] methane is preferred.

The composition of the present invention comprises a polyolefin, a magnetic powder, a compound A and a heavy metal deactivator, and a predetermined amount of the above-mentioned various additives which are usually added to a polyolefin, in a conventional mixing device such as a Henschel mixer (trade name), Mix using a super mixer, ribbon blender, Banbury mixer, etc., and use a normal single-screw extruder, twin-screw extruder, Brabender or roll, etc. to melt and knead temperature 170 ° C to 300 ° C.
Preferably, it can be obtained by melt-kneading and pelletizing at 200 ° C to 250 ° C. In particular, it is preferable to use a twin-screw extruder because the dispersibility of the magnetic powder is improved and a uniform composition can be obtained. The obtained composition is subjected to various molding methods such as an injection molding method, an extrusion molding method and a blow molding method, in particular, an injection molding method to produce a desired molded article. In addition, by performing magnetic field orientation in the above-mentioned various molding methods, those having excellent magnetic properties can be obtained.

[Action] In the present invention, the phosphonate compound represented by the compound A acts to prevent oxidative deterioration and coloration of polypropylene as disclosed in JP-A-54-101846, and a heavy metal deactivator. Are generally known to inactivate the catalytic oxidative deterioration of polyolefins caused by heavy metal ions. However, by using the compound A in combination with the plastic magnet composition containing a heavy metal deactivator, a surprising synergistic effect that cannot be predicted from the conventionally known compound containing an oxidative deterioration preventing effect is exhibited. It has been found that a plastic magnet composition having remarkably excellent long-term thermal stability can be obtained.

[Effects of the Invention] The composition of the present invention is (1) as compared with a conventionally known plastic magnet composition containing a compound having various oxidative deterioration-preventing effects. Excellent long-term thermal stability. (2) It has excellent long-term thermal stability, so it is suitable for use in plastic magnet applications that require long-term thermal stability (for example, small generators, small precision motors, rotation control devices such as VTRs and tape recorders). be able to.

[Examples] Hereinafter, the present invention will be specifically described with reference to Examples, Comparative Examples, and Production Examples, but the present invention is not limited thereto.

The evaluation methods used in Examples and Comparative Examples were as follows.

1) Long-term thermal stability: evaluated by an oven life test. That is, using the obtained pellets, length 50 mm, width 50
mm, 2 mm thick test piece 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
The long-term thermal stability was evaluated by measuring the time until the temperature became (according to JIS K 7212).

Production Example 1 99% by weight of strontium ferrite having an average particle size of 1.1 μ as a magnetic powder and 1% by weight of n-octadecyltriethoxysilane as a surface treatment agent were put in a Hensell mixer (trade name) and mixed with stirring for 5 minutes. To obtain a magnetic powder (I) whose surface was treated.

Production Example 2 Barium ferrite with an average particle size of 1.1μ as magnetic powder 9
Hensell mixer (trade name) containing 9% by weight and 1% by weight of n-octadecyltriethoxysilane as a surface treatment agent.
The resulting mixture was stirred and mixed for 5 minutes to obtain surface-treated magnetic powder (II).

Examples 1 to 14 and Comparative Examples 1 to 6 MFR as polyolefin (discharging amount of molten resin for 10 minutes when a load of 2.16 kg at 230 ° C. is applied) 30 g / 10 minutes unstabilized powdery crystalline ethylene -Propylene block copolymer (ethylene content 8.5% by weight) 15% by weight
And 85% by weight of the magnetic powder (I) in a total of 100 parts by weight, calcium- (3,5-di-t-
Butyl-4-hydroxybenzyl) phosphonate or calcium-bis [O-ethyl- (3,5-di-t
-Butyl-4-hydroxybenzyl) phosphonate], N, N'-bis [2- [3
-(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyloxy] ethyl] oxamide, tris [2
-T-butyl-4-thio (2'-methyl-4'-hydroxy-5'-t-butylphenyl) -5-methylphenyl] phosphite, N, N'-bis [3- (3,5- J-t
-Butyl-4-hydroxyphenyl) propionyl] hydrazine, oxalic acid-bis (benzylidene hydrazide), 3,9-bis [2- (3,5-diamino-2,4,
6-Triazaphenyl) ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane or 2,4,6-triamino-1,3,5-triazine and other additives, respectively The quantity was put into a Henschel mixer (trade name) at the blending ratio shown in Table 1 below, and the mixture was stirred and mixed for 3 minutes.
It was melt-kneaded at 250 ° C. with a 30 mm twin-screw extruder and pelletized. Further, as Comparative Examples 1 to 6, powdery crystalline ethylene-propylene block copolymer having an MFR of 30 g / 10 minutes and not stabilized (ethylene content 8.5% by weight) 15% by weight
And a total of 100 parts by weight of the magnetic powder (I) and 85% by weight, and a predetermined amount of each of the additives described in Table 1 below was mixed and melt-kneaded according to Examples 1 to 14. Pellets were obtained.

The test pieces used for the oven life test were prepared by injection molding the obtained pellets at a resin temperature of 250 ° C and a mold temperature of 50 ° C.

Using the obtained test piece, the long-term thermal stability was evaluated by the above test method. The results are shown in Table 1.

Examples 15 to 28, Comparative Examples 7 to 12 MFR 30 g / 10 min as a polyolefin Unstabilized powdery crystalline propylene homopolymer 13% by weight, MI (19
Discharge of molten resin for 10 minutes when load of 2.16 kg at 0 ° C) 5.0 g / 10 minutes unstabilized powdered Ziegler-Natta high density ethylene homopolymer 1% by weight, Mooney viscosity ML1 + 4 (100 ° C) 25 non-stabilized powdery amorphous ethylene-propylene random copolymer (propylene content 25% by weight) 1% by weight and magnetic powder (II) 85% by weight in total 100% In addition, as compound A, calcium- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate or calcium-bis [O-ethyl- (3,5-di-t-butyl-4-
Hydroxybenzyl) phosphonate], N, N'-bis [2- [3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionyloxy] ethyl] oxamide, tris [2-t-butyl-4]
-Thio (2'-methyl-4'-hydroxy-5'-t-
Butylphenyl) -5-methylphenyl] phosphite, N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, oxalic acid-bis (benzylidene hydrazide) , 3,
9-bis [2- (3,5-diamino-2,4,6-triazaphenyl) ethyl] -2,4,8,10-tetraoxaspiro [5,
5] Undecane or 2,4,6-triamino-1,3,5-triazine and other additives in the respective prescribed amounts at the blending ratios shown in Table 2 below, Hensel Mixer (trade name)
The mixture was stirred and mixed for 3 minutes, and then melt-kneaded at 250 ° C. in a twin-screw extruder having a diameter of 30 mm to form pellets. Further, as Comparative Examples 7 to 12, MFR was 30 g / 10 minutes, 13% by weight of unstabilized powdery crystalline propylene homopolymer, and MI was 5.
Unstabilized powder Ziegler-Natta high density ethylene homopolymer 1% by weight, Mooney viscosity
ML1 + 4 (100 ° C) is a total of 25% of powdered non-stabilized amorphous ethylene-propylene random copolymer (propylene content 25% by weight) and magnetic powder (II) 85% by weight. Predetermined amounts of the additives shown in Table 2 below were added to 100 parts by weight, and melt-kneaded according to Examples 15 to 28 to obtain pellets.

The test pieces used for the oven life test were prepared by injection molding the obtained pellets at a resin temperature of 250 ° C and a mold temperature of 50 ° C.

Using the obtained test piece, the long-term thermal stability was evaluated by the above test method. The results are shown in Table 2.

The compounds and additives relating to the present invention shown in Tables 1 and 2 are as follows.

Compound A [I]: Calcium- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate Compound A [II]: Calcium-bis [O-ethyl- (3,
5-di-t-butyl-4-hydroxybenzyl) phosphonate] Heavy metal deactivator [I]: N, N'-bis [2- [3- (3,3
5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] oxamide heavy metal deactivator [II]: tris [2-t-butyl-4]
-Thio (2'-methyl-4'-hydroxy-5'-t-
Butylphenyl) -5-methylphenyl] phosphite heavy metal deactivator [III]: N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine heavy metal Activator [IV]: Oxalic acid-bis (benzylidene hydrazide) Heavy metal deactivator [V]: 3,9-bis [2- (3,5-diamino-2,4,6-triazaphenyl) Ethyl] -2,4,8,10
-Tetraoxaspiro [5,5] undecane Heavy metal deactivator [VI]: 2,4,6-triamino-1,3,5-
Triazine 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 thioether antioxidant: dimyristyl thiodipropionate phosphorus antioxidant 1: bis (2,4-di-t -Butylphenyl) -pentaerythritol-diphosphite phosphorus antioxidant 2: tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene-di-phosphonite Calcium compound 1: calcium- (Mono, dimixed) stearyl phosphate [Sakai Chemical Industry Co., Ltd.
LBT-1820] Calcium compound 2: Calcium- (mono, dimixed) (pt-butylphenyl) phosphate Calcium compound 3: Calcium-bis [2,2'-methylene-bis (4,6-di-t- Butylphenyl) phosphate] calcium compound 4: 10-hydroxy-9,10-dihydro-
Calcium salt of 9-oxa-10-phosphaphenanthrene-10-oxide Calcium compound 5: calcium carbonate Calcium compound 6: calcium stearate The examples and comparative examples described in Table 1 are the cases where the crystalline ethylene-propylene block copolymer and the magnetic powder (I) were used as the polyolefin. As can be seen from Table 1, in Examples 1 to 14, crystalline ethylene-propylene block copolymer was compounded with magnetic powder (I), compound A and a heavy metal deactivator.
.About.14 and Comparative Examples 1 to 6 (containing calcium compounds other than Compound A instead of Compound A), Examples 1 to 14 are remarkably excellent in long-term thermal stability.
It can be seen that by adding the compound A, a remarkable synergistic effect is recognized. In other words, it is clear that the comparative examples in which a calcium compound other than the compound A according to the present invention is blended do not exhibit the effects of the present invention, which means that the above-mentioned JP-A-62-169858 and JP-A-54-54 Nothing is described in the 101846 publication. That is, the long-term thermal stability obtained in the present invention is peculiar only when the compound A is used in combination with the plastic magnet composition obtained by blending the polyolefin with the magnetic powder and the heavy metal deactivator in the present invention. It can be said to be an effect.

Table 2 shows a mixture of a crystalline propylene homopolymer, a Ziegler-Natta high density ethylene homopolymer and an amorphous ethylene-propylene random copolymer, and a magnetic powder (II) as polyolefin.
Regarding this, the same effect as described above was confirmed.

From this, the plastic magnet composition of the present invention is remarkably excellent in long-term thermal stability, as compared with the plastic magnet composition prepared by compounding a conventionally known compound having an effect of preventing oxidative deterioration. Obviously, the remarkable effect of the composition of the present invention was confirmed.

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Claims (9)

[Claims] 1. A composition comprising 5 to 20% by weight of a polyolefin and 80 to 95% by weight of a magnetic powder, to 100 parts by weight of a composition,
A plastic magnet composition comprising 0.01 to 5 parts by weight of a phosphonate compound represented by the following general formula [I] (hereinafter referred to as compound A) and a heavy metal deactivator. (However, in the formula, R ₁ is hydrogen or an alkyl group having 1 to 8 carbon atoms, R ₂ is an alkyl group having 1 to 8 carbon atoms, and R ₃ is 1 carbon atom.
To 30 alkyl groups, X is 0 or 1, and n is 1 to 4
Indicates the integers of. ) 2. In the general formula [I], R ₁ and R ₂ are t-
The plastic magnet composition according to claim 1, which is a butyl group. 3. The method according to claim 1, wherein calcium-bis [O-ethyl- (3,5-di-t-butyl-4-hydroxybenzyl) phosphonate] is compounded as the compound A. Plastic magnet composition. 4. As a heavy metal deactivator, 2,4,6-triamino-1,3,5-triazine and 3,9-bis [2- (3,5-diamino-2,4,6-triaza) are used. Phenyl) ethyl] -2,4,8,10
-Tetraoxaspiro [5,5] undecane, oxalic acid-bis (benzylidene hydrazide), N, N '
-Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, tris [2-t
-Butyl-4-thio (2'-methyl-4'-hydroxy-5'-t-butylphenyl) -5-methylphenyl]
Phosphite and N, N'-bis [2- [3- (3,5-
The plastic magnet composition according to claim (1), which contains one or more selected from di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] oxamide. 5. The plastic magnet composition according to claim 1, wherein ferrite is used as the magnetic powder. 6. One or two selected from silane coupling agents, titanate coupling agents, boron coupling agents, aluminate coupling agents and zircoaluminate coupling agents as magnetic powders. The plastic magnet composition according to claim (1), wherein the magnetic powder which has been surface-treated with the above surface-treating agent is used. 7. A crystalline propylene homopolymer as a polyolefin, a propylene copolymer containing 70% by weight or more of a propylene component, which is a crystalline ethylene-propylene random copolymer or a crystalline ethylene-propylene block copolymer. , Crystalline propylene-butene-1 random copolymer, crystalline ethylene-propylene-butene-13
The plastic magnet composition according to claim (1), wherein one or more kinds selected from a terpolymer and a crystalline propylene-hexene-butene-1 terpolymer are used. 8. The plastic magnet composition according to claim 1, further comprising a phenolic antioxidant. 9. A phenolic antioxidant, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-).
Hydroxybenzyl) benzene, 1,3,5-tris (3,5-
Di-t-butyl-4-hydroxybenzyl) isocyanurate, 3,9-bis [1,1-dimethyl-2- {β- (3-
t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 1,3,5-tris [(3,5- Di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate and tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane The plastic magnet composition according to claim (8), wherein one kind or two or more kinds are blended.