JPH01131259A - Plastic magnet composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition, having excellent resistance to deterioration by heat and oxidation and suitable as small-sized generators, etc., by blending a composition consisting of a polyolefin and magnetic substance powder with zinc or magnesium salt of a carboxylic acid or heavy metal inactivator in specific amounts. CONSTITUTION:A composition obtained by blending (A) 100 pts.wt. composition consisting of (A1) 5-20wt.% polyolefin (e.g., crystalline propylene polymer) and (A2) 80-95wt.% magnetic substance powder (e.g., ferrite) having the surface treated with a coupling agent with (B) 0.01-5 pts.wt. zinc or magnesium salt of a carboxylic acid [e.g., zinc (magnesium) 2-ethylhexanoate or zinc (magnesium) stearate] and (C) 0.01-5 pts.wt. heavy metal inactivator (e.g., 2,4,6- triamino-1,3,5-triazine). Furthermore, (D) a phenolic antioxidant is preferably blended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plastic magnet composition. More specifically, the present invention relates to a plastic magnet composition that has excellent resistance to thermal oxidative deterioration during practical use.

[Prior Art] Sintered ferrite magnets, samarium cobalt alloy magnets, and the like have been widely used as permanent magnets in the fields of heavy electrical appliances, home appliances, electronic devices, and the like. However, these magnets require secondary processing such as mechanical bending, cutting, and polishing, which poses a serious obstacle to expanding their use in the above-mentioned fields.

Therefore, in order to solve the above-mentioned problems, a composite material, so-called plastic magnet, in which magnetic powder is blended with various synthetic resins, has been developed and is now widely put into practical use. However, when polyolefins, especially propylene-based polymers, are used as synthetic resins for plastic magnets, propylene-based polymers contain tertiary carbon, which is susceptible to oxidation, and therefore are not included in the magnetic powder. The heat oxidative deterioration resistance of plastic magnets in practical use is
Hereinafter, this is referred to as long-term thermal stability. ), which causes problems such as a significant decrease in

For this reason, in order to improve the long-term thermal stability of plastic magnets using polyolefin, we have developed compositions in which heavy metal deactivators are added to plastic magnets, and in which the kneading torque of the molding machine is reduced. A composition (Japanese Patent Laid-Open No. 169858/1983) has been proposed in which a lubricant consisting of a metal soap is used in combination to improve mold release properties during molding or molding and to smooth the surface of the molded product.

[Problems to be Solved by the Invention] However, the plastic magnet composition proposed in the above-mentioned Japanese Patent Application Laid-open No. 169858/1983, which is a plastic magnet using a polyolefin and a heavy metal deactivator, is not stable over a long period of time. Although the quality has improved considerably, it is still not completely satisfactory. Furthermore, in the above-mentioned Japanese Patent Application Laid-Open No. 62-169858, there is no mention that among the metal soaps used in combination, zinc salts or magnesium salts of carboxylic acids have the effect of improving the long-term thermal stability of plastic magnet compositions. , and there is no description even suggesting the above effects.

The inventors of the present invention have conducted extensive research to solve the above-mentioned problems with the plastic magnet compositions, that is, the long-term thermal stability problems. As a result, a composition comprising a plastic magnet made of polyolefin and magnetic powder mixed with specific amounts of a zinc salt or magnesium salt of carboxylic acid (hereinafter referred to as compound A) and a heavy metal deactivator was obtained. It was discovered that the problems of plastic magnet compositions could be solved, and the present invention was completed based on this knowledge.

As is clear from the above description, an object of the present invention is to provide a plastic magnet composition which, when formed into a molded article, has excellent long-term thermal stability.

[Means for solving problems] The present invention has the following configuration.

5 to 20% by weight of polyolefin and 80 to 80% of magnetic powder
Zinc salt of carboxylic acid or magnesium salt of carboxylic acid (
Hereinafter, it will be referred to as compound A. ) and heavy metal deactivator, respectively. A plastic magnet composition containing 1 to 5 parts by weight of O.

The polyolefins used in the present invention include crystalline homopolymers of α-olefins such as ethylene, propylene, butene-1, pentene-1,4-methyl-pene, ten-1, hexene-1, and octene-1; Crystalline, low-crystalline or non-crystalline random copolymers or crystalline block copolymers of two or more α-olefins, amorphous ethylene-propylene-nonconjugated diene ternary copolymers, the above-mentioned α- Copolymers of olefins and vinyl acetate or acrylic esters, saponified products of these copolymers, copolymers of these α-olefins and unsaturated silane compounds, these α-olefins and unsaturated carboxylic acids or their anhydrides A copolymer with, a reaction product of the copolymer and a metal ion compound,
Examples include modified polyolefins in which polyolefins are modified with unsaturated carboxylic acids or derivatives thereof, and silane-modified polyolefins in which polyolefins are modified with unsaturated silane compounds. It is also possible to use a mixture of polyolefins. In addition, the above-mentioned polyolefins 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-pro and lene-butylene-styrene block copolymer, etc.) or thermoplastic synthetic resin (e.g. polystyrene,
A mixture of styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyvinyl chloride, fluororesin, etc.) can also be used. Crystalline propylene homopolymer, propylene copolymer containing 70% by weight or more of propylene component, including crystalline ethylene-propylene random copolymer, crystalline ethylene-propylene block copolymer, crystalline propylene-butene- 1 random copolymer, crystalline ethylene-propylene-butene-
A 13-element copolymer, a crystalline propylene-hexene-butene-13-element copolymer, and a mixture of two or more thereof are particularly preferably used.

Magnetic powders used in the present invention include 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 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, with strontium ferrite and barium ferrite being particularly preferred. The particle size of these magnetic powders is not particularly limited, but is usually 0.5μ to 50μ
, preferably from 0.5μ to 10μ, most preferably from 1μ to 5μ. In addition, these magnetic powders can be treated with known surface treatment agents such as silane coupling agents, titanate coupling agents, boron coupling agents, aluminate coupling agents, and zircoaluminate coupling agents. When the surface is treated with a plastic magnet beforehand, the compatibility and dispersibility of the magnetic powder and polyolefin are improved, and excellent moldability is obtained. Since the mechanical strength of the molded article is improved, it is preferable to use magnetic powder whose surface has been treated with a surface treatment agent. Of course, these magnetic powders can be used alone, but two or more types of magnetic powders can also be used in combination. The blending ratio of the magnetic powder is
The amount is 80 to 95% by weight based on the composition consisting of polyolefin and magnetic powder. When 80% by weight is ungrooved, the plastic magnet composition has good moldability, but the magnetic properties are insufficient, and when it exceeds 95% by weight, moldability becomes difficult and the resulting molded product has poor mechanical properties. The strength also decreases, making it impractical.

Compound A used in the present invention includes fatty acid zinc, fatty acid magnesium (fatty acids include, for example, acetic acid, n-
Propionic acid, n-butyric acid, n-valeric acid, n-hexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, n-decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid , linuric acid, hehenic acid, erucic acid, lignoceric acid, cerotic acid and montanic acid), zinc triphenylacetate, magnesium triphenylacetate, zinc aliphatic dicarboxylate, magnesium aliphatic dicarboxylate (as aliphatic dicarboxylic acids) , such as oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid), zinc naphthenate, magnesium naphthenate, zinc aromatic carboxylate and magnesium aromatic carboxylic acid (for example benzoic acid) , 0-toluic acid, m-)ruic acid, p-)ruic acid, pt-butylbenzoic acid, O-methoxybenzoic acid, m-methoxybenzoic acid, anisic acid, phthalic acid, isophthalic acid and terephthalic acid. ), with fatty acid zinc or fatty acid magnesium being particularly preferred. Although it is possible to use the zinc salt or magnesium salt of these carboxylic acids alone, it is also possible to use two or more zinc salts or magnesium salts of the carboxylic acids in combination. The blending ratio of the compound A is 0.01 to 5 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the composition consisting of 5 to 20% by weight of polyolefin and 80 to 95% by weight of magnetic powder.
2 parts by weight. If the amount is less than 0.01 part by weight, the plastic magnet composition will not have a sufficient effect of preventing oxidative deterioration, and although it may be more than 5 parts by weight, no further improvement in the effect of preventing oxidative deterioration can be expected. Not only is this impractical, but it is also uneconomical.

The heavy metal deactivators used in the present invention include hensitriazole, 2,4,6-)riamino-1,3,5-
triazine, 3,9-bis[2-(3,5-diamino-
2,4,6-)riazaphenyl)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-pro and diamine, N.

N 11-disalicylidene-N'-methyl-dipropylene triamine, 3-salicyloyl amino-1,2,4-
) lyazole, decamethylenedicarboxylic acitobis(N'-salicyloylhydrazide), nickel-bis(l-phenyl-3-methyl-4-decanoyl-
5-virazolate), 2-ethoxy-2'-ethyloxanilide, 5-t-butyl-2-ethoxy-2''-ethyloxanilide, N,N-diethyl-N', N'-
diphenyloxamide, N,N"-diethyl-N,N'
- diphenyl oxidide, oxalic acid bis(benzylidene hydrazide), thiodibrobionic acid bis(benzylidene hydrazide), isophthalic azide bis(2-phenoxypropionyl hydrazide), bis(salicyloylhydrazine), N-salicylidene-N'-salicyloylhydrazone, N,N
'-bisC3-(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-di-t-butyl-4-hydroxyphenyl)
Examples include propionyloxy]ethyl]oxamide, in particular 2,4,6-)riamino-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'-t-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 can be used alone, but two or more heavy metal deactivators can be used together). An activator can also be used in combination.The blending ratio of the heavy metal deactivator is 0.01 to 100 parts by weight of a composition consisting of 5 to 20% by weight of polyolefin and 80 to 95% by weight of magnetic powder. The amount is 5 parts by weight, preferably 0.05 to 2 parts by weight.If the amount is less than 0.01 part by weight, the effect of preventing oxidative deterioration of the plastic magnet composition will not be sufficiently exhibited, and if it is more than 5 parts by weight, there is no problem. However, it is not only impractical but also uneconomical since no further improvement in the effect of preventing oxidative deterioration can be expected.

The composition of the present invention includes various additives that are usually added to polyolefins, such as phenol-based, thioether-based, phosphorus-based antioxidants, light stabilizers, clarifying agents, etc.
Nucleating agents, lubricants, antistatic agents, antifogging agents, antiblocking agents, anti-drop agents, pigments, radical generators such as peroxides,
Dispersants or neutralizing agents for metal soaps, inorganic fillers (
For example, 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 fibers, etc.) or coupling agents (such as silane-based, titanate-based, boron-based,
For the purpose of the present invention, the inorganic filler or organic filler surface-treated with a surface treatment agent such as aluminate-based, zirco-aluminate-based, etc. They can be used together as long as they do not cause any damage. In particular, when a phenolic antioxidant is used in combination, the effect of preventing oxidative deterioration is exhibited synergistically, so it is preferable to use them together.

As a phenolic antioxidant, 2,6-diphenyl-
4-octadecyloxyphenol, 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,l-dimethyl-2-{ β-(3-t-butyl-4-hydroxy-5-
methylphenyl)propio-nyloxy)ethyl]-2
．． 4,8.10-tetraoxaspiro[5,5]undecane, 3,9-bis[1,l-dimethyl-2-{β-(
3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy)ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, 3,9-bis[1,l-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゜11.6-tris(3,5-
di-t-butyl-4-hydroxybenzyl)benzene,
1,3.5-tris(3,5-di-7-butyl-4-hydroxybenzyl)isocyanurate,! , 3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 1,3.5-tris[(3,5-di-t-butyl-4-hydroxy) Examples include phenyl)propionyloxyethyl]isocyanurate and tetrakis[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate 3methane, especially 1,3.5-) Dimethyl-2,4,6-tris(3,5-di-t-butyl-4
-hydroxybenzyl)benzene, 1,3.5-)lis(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 1-2.
4,8.10-tetraoxaspiro[5,5]undecane, 1,3,5-)lis[(3,5-di-t-butyl-4-hydroxyphenyl)probionyloxyethyl coisocyanurate and tetrakis [Methylene-3-
(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate comethane is preferred.

The composition of the present invention is prepared by mixing polyolefin with predetermined amounts of magnetic powder, Compound A, a heavy metal deactivator, and the above-mentioned various additives that are usually added to polyolefin using a conventional mixing device such as a Hensel mixer (trade name). Mix using a super mixer, ribbon blender, Pan Bali mixer, etc., and melt and knead with a normal single screw extruder, twin screw extruder, Brabender or roll, etc. at a melt-kneading temperature of 170°C to 30°C.
It can be obtained by melt-kneading and pelletizing at 0°C, preferably 200°C to 250°C. In particular, it is preferable to use a twin-screw presser because the dispersibility of the magnetic powder is improved and a uniform composition can be obtained. The obtained composition is used to produce a desired molded article by various molding methods such as injection molding, extrusion molding, and blow molding, especially injection molding. In addition, by performing magnetic field orientation in the above-mentioned various molding methods, products with excellent magnetic properties can be obtained.

[Function] In the present invention, the zinc salt or magnesium salt of the carboxylic acid represented by compound A, that is, the metal soap is disclosed in JP-A-62
As disclosed in Japanese Patent No. 169858, the heavy metal deactivator acts as a lubricant to improve the moldability of the plastic magnet composition, and the heavy metal deactivator deactivates the catalytic oxidative deterioration of polyolefin caused by heavy metal ions. It is generally known that however,
By using Compound A in combination with a plastic magnet composition containing a heavy metal deactivator, a surprising synergistic effect that cannot be predicted from the combination of conventionally known compounds with oxidative deterioration prevention effects is exhibited, resulting in long-term It has been found that a plastic magnet composition with significantly excellent thermal stability can be obtained.

[Effects of the Invention] Compared to conventionally known plastic magnet compositions containing compounds having various oxidative deterioration prevention effects, the composition of the present invention has a (+) Excellent long-term thermal stability. (2) It has excellent long-term thermal stability, making it suitable for plastic magnet applications that require long-term thermal stability (for example, small generators, small precision motors, and rotation control devices such as VTRs and tape recorders). Can be used.

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

The evaluation method used in Examples and Comparative Examples was as follows.

1) Long-term thermal stability: Evaluated by oven life test. That is, a test piece with a length of 50 mm, a width of 50 mm, and a thickness of 2 mm was made by injection molding using the obtained pellets, and the test piece was placed in a circulating hot air oven adjusted to a temperature of 150°C. Time until complete deterioration (
Measurement of the time taken for the tensile strength to reach O (JIS
Long-term thermal stability was evaluated according to K 7212).

Production Example 1 99% by weight of strontium ferrite with an average particle size of 1.1μ as a magnetic powder and 11% of n-ophtadecyltriethoxysilane as a surface treatment agent were mixed in a Hensel mixer (
(trade name) and stirred and mixed for 5 minutes to obtain a surface-treated magnetic powder (1).

Production Example 2 99% by weight of barium ferrite with an average particle size of 1.1μ as magnetic powder and 1% by weight of n-octadecyltriethoxysilane as a surface treatment agent were placed in a Hensel mixer (trade name) and mixed by stirring for 5 minutes. A surface-treated magnetic powder (II) was obtained.

Examples 1 to 6, Comparative Examples 1 to 6 MFR (load ff at 230°C) as polyolefin
Discharge of molten resin in 10 minutes when adding 12.16 kg of unstabilized powdered crystalline ethylene-propylene block copolymer (ethylene content 8.5% by weight) 15 wt. % and 85% by weight of magnetic powder (1), zinc stearate or magnesium stearate as compound A, and N,N'-bis[2] as a heavy metal deactivator.
-(3-(3,5-di-t-butyl-4-hydroxyphenyl)probionyloxy]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. io-tetraoxaspiro[5,
5] undecane or 2,4.6- ) riamino-1
, 3,5-triazine and other additives in the mixing ratios listed in Table 1 below in a Hensel mixer (trade name), stirred and mixed for 3 minutes, and then
The mixture was melt-kneaded and pelletized at 250° C. using a 0m+m twin-screw press ratio machine. Also, as Comparative Examples 1 to 6, MFR is 30
g/10 min of unstabilized powdered crystalline ethylene-propylene block copolymer (ethylene content 8.
A total of 100 parts by weight consisting of 15% by weight) and 85% by weight of magnetic powder (1) was blended with predetermined amounts of each of the additives listed in Table 1 below, and the mixture was prepared in accordance with Example 1-14. Then, a pellet was obtained by melt-kneading.

The test piece used in the oven life test was prepared by injection molding the obtained pellet at a resin temperature of 250°C and a mold temperature of 50°C.

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

Examples 15-28, Comparative Examples 7-12 Unstabilized powdered crystalline propylene homopolymer 1 with MFR 30 g/10 min as polyolefin
3% by weight, Ml (discharge amount of molten resin in 10 minutes when applying a load of 2.16kg at 190°C) 5.0g
/ 10 min unstabilized powder Ziegler-Natsuta high density ethylene homopolymer 1% by weight, unstabilized powder non-grade ethylene-propylene random with Mooney viscosity M L +44 (100°C) 25 To a total of 100 weight % of the copolymer (propylene content 25 weight %) and 85 weight % magnetic powder (II),
Zinc stearate or magnesium stearate as a compound, N as a heavy metal deactivator.

N-bis[2-(3-(3,5-di-t-butyl-4
-hydroxyphenyl)propionyloxy]ethyl]
Oxamide, tris[2-1-butyl-4-thio(2'
-Methyl-4'-hydroxy-5'-1-butylphenyl)-5-methylphenyl]phosphite, N,N
'-bis[3-(3,5-sheet-t-butyl-4-hydroxyphenyl)propionyl]hydrazine, oxalic acid-bis(benzylidenehydrazide), 3,
9-bis[2-(3,5-diamino-2,4,6-)riazaphenyl)ethyl]-2゜4.8.10-tetraoxaspiro[5,5]undecane or 2,4.6-
Predetermined amounts of triamino-1,3,5-triazine and other additives were placed in a Hensel mixer (trade name) at the mixing ratios listed in Table 2 below, and after stirring and mixing for 3 minutes, The mixture was melt-kneaded at 250° C. using a twin-screw press to form pellets. Further, as Comparative Examples 7 to 12, 13% by weight of unstabilized powdery crystalline propylene homopolymer with an MFR of 30 g/10 min and an MI of 5.0
g/10 minutes of unstabilized powdered Ziegler powder.
Natsuta-based high-density ethylene homopolymer 1% by weight, unstabilized powdery non-grade engineered ethylene-propylene random copolymer with Mooney viscosity M L ++4 (100°C) of 25 (propylene content 25% by weight) A total of 100 parts by weight consisting of 1% by weight and 85% by weight of magnetic powder (II) was blended with predetermined amounts of each of the additives listed in Table 2 below, and melted according to Examples 15 to 28. Pellets were obtained by kneading.

The test pieces used in the oven life test were prepared by injection molding the obtained pellets at a resin temperature of 2-50°C and a mold temperature of 50°C.

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

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

Compound A [I] Zinc nistearate Compound A [II] Magnesium nistearate heavy metal deactivator [1]: N,N'-bis[2-(3-(3
,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethyl]oxamide heavy metal deactivator [1]:) Lis[2-t-butyl-4
-thio(2'-methyl-4'-hydroxy-5'-t-
butylphenyl)-5-methylphenyl]phosphite heavy metal deactivator [111]: N,N'-bis[
3-(3,5-di-t-butyl-4-hydroxyphenyl)propionylcohydrazine Heavy metal deactivator [■] Nioxalic acid bis(benzylidene hydrazide) Heavy metal deactivator [V]: 3, 9-bis[2-(3,5
-diamino-2,4,6-)riazaphenyl)ethyl]
-2゜4.8.10-Tetraoxaspiro[5,5]undeforced 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 comethane thioether antioxidant Nizimyristylthiodipropionate phosphorus antioxidant 1: Bis(2,4-di- t-butylphenyl)-pentaerythritol-siphosphite phosphorus antioxidant 2: Tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene-diphosphonite Li-3t di Lithium stearate Na-3t: Sodium stearate Ca-3t Calcium nistearate 5r-St: Strontium stearate Ba-5t
Barium Nistearate AQ-St Aluminum Nistearate The Examples and Comparative Examples listed in Table 1 are cases where a crystalline ethylene-propylene block copolymer and magnetic powder (1) are used as the polyolefin. As can be seen from Table 1,
Example 1-14 is a crystalline ethylene-propylene block copolymer blended with magnetic powder (I), Compound A, and a heavy metal deactivator, and Example 1-14 and Comparative Examples 1-6 ( When compared with those in which a metal salt of a carboxylic acid other than Compound A was blended in place of Compound A, Examples 1 to 14 had significantly superior long-term thermal stability. It can be seen that a synergistic effect is observed. In other words, it is clear that the comparative compounds containing metal salts of carboxylic acids other than Compound A according to the present invention do not exhibit the effects of the present invention, and this is not mentioned in the above-mentioned JP-A No. 62-69858. It has not been. In other words, the long-term thermal stability obtained in the present invention can only be seen when Compound A is used in combination with an acid (plastic magnet made by blending a magnetic powder and a heavy metal deactivator with a polyolefin). This can be said to be a unique effect.

Table 2 shows polyolefins using a mixture of a crystalline propylene homopolymer, a Ziegler-Natsuta high-density ethylene homopolymer, a non-grade ethylene-propylene random copolymer, and magnetic powder (II), In this case, the same effect as described above was confirmed.

This shows that the plastic magnet composition of the present invention is significantly superior in terms of long-term thermal stability compared to plastic magnet compositions containing conventionally known compounds that have the effect of preventing oxidative deterioration. The remarkable effects of the composition of the present invention were confirmed.

that's all

Claims (1)

Scope of Claims (1) A zinc salt of a carboxylic acid or a magnesium salt of a carboxylic acid (hereinafter referred to as a compound A plastic magnet composition comprising 0.01 to 5 parts by weight of each of A) and a heavy metal deactivator. (2) The plastic magnet composition according to claim (1), which contains one or more compounds selected from zinc fatty acids and zinc aromatic carboxylates as compound A. (3) Claim No. 1 in which one or more compounds selected from zinc 2-ethylhexanoate, zinc stearate, and zinc montanate are blended as compound A.
The plastic magnet composition described in . (4) The plastic magnet composition according to claim (1), which contains one or more compounds selected from magnesium fatty acids and magnesium aromatic carboxylates as compound A. (5) The plastic magnet composition according to claim (1), which contains one or more compounds selected from magnesium 2-ethylhexanoate, magnesium stearate, and magnesium montanate as compound A. thing. (4) 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, 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-di-t-butyl-4
-hydroxyphenyl)propionyloxy]ethyl]
The plastic magnet composition according to claim (1), which contains one or more selected from oxamides. (5) The plastic magnet composition according to claim (1), which uses ferrite as the magnetic powder. (6) One or more types selected from silane coupling agents, titanate coupling agents, boron coupling agents, aluminate coupling agents, and zircoaluminate coupling agents as the magnetic powder. The plastic magnet composition according to claim (1), which uses magnetic powder that has been surface-treated with a surface treatment agent. (7) A crystalline propylene homopolymer or a propylene copolymer containing 70% by weight or more of a propylene component as a polyolefin, such as a crystalline ethylene-propylene random copolymer, a crystalline ethylene-propylene block copolymer, or a crystalline propylene copolymer. propylene-butene-1 random copolymer, crystalline ethylene-propylene-butene-1 tertiary copolymer and crystalline propylene-hexene-butene-13
The plastic magnet composition according to claim (1), which uses one or more selected from the original copolymers. (8) The plastic magnet composition according to claim (1), which contains a phenolic antioxidant. (9) As phenolic antioxidants, 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] The claim 8 contains one or more selected from methane. Plastic magnet composition.