JPH078941B2 - Plastic magnet composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plastic magnet composition, and particularly has excellent thermal and mechanical properties, low molding shrinkage, low linear expansion coefficient, flame retardancy, and good moldability. It relates to a composition.

<Prior art and its problems> Although plastic magnets are inferior in magnetic properties to sintered magnets, the final product can be easily obtained by injection molding, and lightweight and complex shapes are possible. There is an advantage that can be taken.

Epoxy resins and polyamides (6-nylon, 66 nylon) are often used as binder resins for plastic magnets.

The mechanical strength, heat resistance, etc. of a plastic magnet composition are determined by the resin used as a binder. Particularly, heat resistance is 100-120 ° C for nylon, if epoxy resin is used, It is 140 to 160 ° C. In order to expand the applications of plastic magnet compositions in the future, it is important to increase the heat resistance, but in general, if a resin with high heat resistance is used, the moldability will deteriorate and the advantages of plastic magnet compositions will increase. The reality is that complicated molding and multi-cavity production cannot be performed.

<Object of the invention> The object of the present invention is to improve the above-mentioned drawbacks of the prior art and to achieve high heat resistance, high strength and high elastic modulus in spite of low melting temperature and melt viscosity and good moldability. It is intended to provide a plastic magnet composition having excellent moldability, high heat resistance, high strength, and high elastic modulus by using the specified specific aromatic polyester as a binder resin.

<Structure of the Invention> The present invention substantially consists of each unit represented by the following formulas I, II, III, IV and V: V-O-Ar-O- (however, X in the formula is H, an alkyl group of _{C 1 ~C 4, C 1 ~C} 4
An alkoxy group, an aryl group or a halogen C ₆ -C _10, also, -O-Ar-O- is in the formula in symmetry dioxy unit having an aromatic ring of at least one monocyclic or condensed And Y is -O- or Is).

Unit I 40 to 70 mol% Unit II 1 to 8 mol% Unit III + unit IV 6 to 36 mol% Unit V 10 to 40 mol% and the molar ratio of unit III / (unit III + unit IV) is 0.1 to
A plastic magnet composition comprising 100 to 1900 parts by weight of a powdery magnetic material with respect to 100 parts by weight of an aromatic polyester of 0.8.

The present invention is described in detail below.

First, the aromatic polyester used in the composition of the present invention will be described, and then the powdery magnetic substance will be described.

The aromatic polyester used in the composition of the present invention is substantially composed of the following units (I) to (V).

(1) In the unit (I) of p-hydroxybenzoic acid, the benzene nucleus thereof is C ₁ -C ₄ -alkyl, C ₁ -C ₄ alkoxy, C _6- .
C ₁₀ -aryl or halogen (preferably chlorine,
It may be p-hydroxybenzoic acid substituted with bromine).
Preferable examples are unsubstituted p-hydroxybenzoic acid, and typical examples thereof include ester-forming derivatives such as acetate, propionate, benzoate, methyl, ethyl and phenyl.

The unit (I) should be contained in the amount of 40 to 70 mol%, preferably about 45 to 65 mol%, of calcination. When the unit (I) is less than 40 mol% and more than 70 mol%, the mechanical strength of the produced polyester is lowered.

(2) The unit (II) is an isophthaloyl moiety represented by the following formula (II-i) and / or an m-hydroxybenzoic acid moiety represented by the following formula (II-ii).

(II-i) and the benzene nucleus of (II-ii) is, C ₁ ~C ₄ -
Alkyl, C ₁ -C ₄ - alkoxy, C ₆ -C ₁₀ - aryl,
Alternatively, it may be substituted with halogen (preferably chlorine or bromine).

The unit (II-i) is an isophthaloyl moiety, and representative examples thereof include isophthalic acid and / or methyl, ethyl, phenyl or diester derivatives of isophthalic acid. The unit (II-ii) is an m-hydroxybenzoic acid moiety, and representative examples thereof include m-hydroxybenzoic acid and / or mono- or diester derivatives of acetate, propionate, benzoate, methyl, ethyl, phenyl.

The unit (II) represented by (II-i) and / or (II-ii) is about 1-8 mol%, preferably 2-5 mol%.

When the unit (II) is less than 1 mol%, the flow temperature of the polyester becomes high and it is difficult to mold, and when the unit (II) exceeds 8%, the heat resistance of the polyester is lowered.

(3) As the unit (III) and the unit (IV), terephthalic acid and 2,6-naphthalenedicarboxylic acid and their methyl, ethyl and phenyl mono- or diester derivatives can be representatively mentioned.

Unit (III) + terminal (IV) is 6 to 36 mol%, preferably 1
It is 2 to 27 mol%. The molar ratio [(III) / {(III) + (IV)}] of the unit (III) and the unit (IV) is 0.1 to 0.8, preferably about 0.3 to 0.7. This is because if the molar ratio is less than 0.1, the flow temperature of the polyester becomes high and it is difficult to mold, and if it is more than 0.8, the flow temperature becomes high and it becomes difficult to mold.

If the unit (III) + unit (IV) is less than 6 mol%, the flow temperature of the polyester becomes high and it is difficult to mold, and if the unit (III) + unit (IV) exceeds 36 mol%, the aromatic polyester is Coloring is easy and mechanical strength is reduced.

(4) The unit (V) is a symmetric dihydroxy compound,
It is represented by HO-Ar-OH, and Ar means a divalent group composed of at least one aromatic ring. The unit (V) is contained in an amount of 10 to 40 mol%, preferably 17.5 to 27.5 mol%.

Examples of the symmetric dihydroxy aromatic compound include those forming the following units in the copolyester.

In particular, there are hydroquinone, bisphenol A, 4,4'-dihydroxybiphenyl, dihydroxybiphenyl ether, 2,6-dihydroxynaphthalene and the like, or mono- or diester derivatives thereof such as acetate, propionate and benzoate. Particularly preferred compounds are 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene. If the unit (V) is less than 10 mol%, the flow temperature of the polyester becomes high and it is difficult to mold, and if the unit (V) exceeds 40 mol%, the heat resistance of the polyester decreases, which is not preferable.

The polymerization method is not particularly limited, and any polymerization method may be used as long as the units (I) to (V) are present in the aromatic polyester in the composition ratio of the present invention.

The powdery magnetic material used in the present invention is not particularly limited,
MOFe ₂ O ₃ (where M is Ba, Ca, Mg, Mn, Fe, Cu, Ni, C
o, Zn, Pb) ferrite magnetic powder or RCO
₅ (R is a rare earth element such as Sm, Pr, Ce and La), Sm ₂ X ₁₇ (X
Are rare earth magnetic powders such as Co, Fe, Cu, Zr, Ti, Hf) NdFeB. These may be one kind or a mixture of two or more kinds.

The preferable particle size of the magnetic powder used in the present invention is not particularly limited, but is preferably about 0.1 to 100 μm, more preferably about 1 to 50 μm.

If the particle size is less than 0.1 μm, the particles tend to agglomerate and the magnetic powder cannot be uniformly dispersed in the composition, while the particle size is 100 μm.
When it exceeds, the smoothness of the surface is lost, the appearance is deteriorated, and the molding process becomes extremely difficult.

The content of magnetic powder is 100 to 100 parts by weight of binder resin.
It is preferably 1900 parts by weight, more preferably 400 to 1150 parts by weight. If it is less than 100 parts by weight, the magnetic properties of the molded product will be remarkably reduced, and it will no longer function as a magnet.

Further, if it exceeds 1900 parts by weight, the fluidity at the time of melting is deteriorated, which makes molding processing extremely difficult, and the mechanical strength of the molded product is reduced.

The magnetic powder used in the present invention may be surface-treated. Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, borane coupling agents; higher fatty acids; wetting agents such as surfactants. These surface treatment agents may be adsorbed on the surface of the magnetic powder before kneading the resin and the magnetic powder, or may be supplied into the kneading device together with the resin and the magnetic powder when kneading.

Examples of a device for kneading these magnetic powders into a resin include a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, a two-roll mill, and a braventer. Further, a method of adding and mixing magnetic powder to the resin melted in the reaction vessel, and a method of molding while mixing the resin and magnetic powder in a molding machine are also possible.

The composition of the present invention may contain other components in addition to the above-mentioned essential components as long as the object of the present invention is not impaired.

Further, the resin component may be a copolymer or mixture of the aromatic polyester of the present invention and the aromatic polyester amide containing an amide component therein.

Other resins in the composition of the present invention, antioxidants; anti-staining agents; stabilizers; UV absorbers; plasticizers; lubricants such as molybdenum disulfide, silicon oil, fluororesins, graphite; tetrabromobisphenol A, A flame retardant such as antimony trioxide may be added.

<Examples> Examples will be described in more detail below.

First, the test method will be described.

(1) Preparation of test material A φ20 m / m single-screw extruder (Thermo Plastics Industry Co., Ltd.) is used to melt-knead a resin and an inorganic substance at a predetermined ratio to form a pellet. Using an injection molding machine (Yamashiro Seiki Seisakusho SAV-60-52 type), the pellets thus obtained were subjected to a mold temperature of 120.
° C., injection pressure 250 Kg / cm ^2, cylinder temperature resin is molded in the temperature to be completely filled in the mold.

(2) Injection molding temperature The cylinder temperature at the time of injection molding was used as the injection molding temperature, and the lower the temperature, the better the moldability.

(3) Bending test Molded into a 1/2 x 5 x 1/4 bar with an injection molding machine and
It was measured according to TM-D790.

(4) Heat distortion temperature Measured at 18.6 Kg / cm ² according to ASTM D648.

(5) Magnetic properties A test piece with a diameter of 1 inch and a thickness of 1/2 inch was prepared from the molded sample, and its residual magnetic flux density Br and coercive force Hc were measured using a BH loop measurement device (Yokogawa Electric Co., Ltd.). And the maximum energy product (BH) max was measured.

Next, examples and comparative examples of the aromatic polyester composition of the present invention will be described.

(Example 1) Argon introduction tube, stirrer with tachometer and torque meter,
In a 5 liter glass reaction vessel equipped with a thermometer, p-acetoxybenzoic acid 6.66 mol (1200 g), isophthalic acid, 0.334 mol (55.4 g) terephthalic acid 0.778 mol (129 g), 2,6-naphthalenedicarboxylic acid 1.112 mol ( 240 g) and 4,2'-diacetoxybiphenyl (2.22 mol, 600 g) were added, and after the atmosphere was replaced with argon, the internal temperature was raised to 250 ° C in about 30 minutes, and stirring was started when the raw materials were melted.

After 10 minutes from the start of distillation of acetic acid, the temperature was raised to 280 ° C, the reaction was performed at this temperature for 30 minutes, and the temperature was further raised to 300 ° C over 10 minutes, and the reaction was performed at this temperature for 30 minutes.

Then, the temperature was raised to 310 ° C. over 10 minutes, and then the pressure was gradually reduced over about 20 minutes to finally reach 1 mmHg, and the polymerization was continued under these conditions. The reaction was terminated when a predetermined torque was reached at a predetermined stirring speed.

The polymer obtained in this way is solidified and then crushed, and a φ20m extruder (made by Thermo Plastic Industry Co., Ltd.) is used to produce Ba-based ferrite TR-M (made by Tone Sangyo Co., Ltd.) and resin: ferrite = 1: 9 weight ratio. After kneading, the mixture was pelletized and injection molded.

Table 1 shows the measurement results of the physical properties of the molded products.

(Example 2) p-acetoxybenzoic acid 4.44 mol (800
g), isophthalic acid 0.334 mol (55.4g), terephthalic acid
1.5 mol (248.7g), 2.6-naphthalenedicarboxylic acid 1.5
Molar (323.7g), 4,4'-diacetoxybiphenyl 3.33
Aromatic polyester was synthesized in the same manner as in Example 1 except that mol (900 g) was used as the raw material, and the same aromatic Ba as used in Example 1 was used for the obtained aromatic polyester.
The system ferrites were mixed, kneaded, adjusted, and evaluated by the same method and ratio.

The results are shown in Table 1.

(Example 3) p-acetoxybenzoic acid 7.215 mol (1300 g), isophthalic acid 0.334 mol (55.4 g), terephthalic acid 0.806 mol (13
3.8 g), 2,6-naphthalenedicarboxylic acid 0.806 mol (174
g), 4,4'-diacetoxybiphenyl 1.943 mol (525
Aromatic polyester was synthesized in the same manner as in Example 1 except that g) was used as the raw material, and the Ba-based ferrite used in Example 1 was mixed with the obtained aromatic polyester in the same method and proportion. , Kneading, adjustment, and evaluation of physical properties were performed.

The results are shown in Table 1.

(Example 4) p-acetoxybenzoic acid 7.215 mol (1300 g), isophthalic acid 0.361 mol (59.9 g), terephthalic acid 0.409 mol (67.
9g), 2,6-naphthalenedicarboxylic acid 1.635 mol (353.2
g), 4,4'-diacetoxybiphenyl 2.405 mol (649.4
An aromatic polyester was synthesized in the same manner as in Example 1 except that g) was used as a raw material, and the Ba-based ferrite used in Example 1 was mixed with the obtained aromatic polyester in the same manner and in the same proportion. , Kneading, adjustment, and evaluation were performed.

The results are shown in Table 1.

(Example 5) p-acetoxybenzoic acid 7.215 mol (1300 g), isophthalic acid 0.361 mol (59.9 g), terephthalic acid 1.323 mol (21
9.6 g), 2,6-naphthalenedicarboxylic acid 0.722 mol (156
g), 4,4'-diacetoxybiphenyl 2.405 mol (649.4
Aromatic polyester was synthesized in the same manner as in Example 1 except that g) was used as the raw material, and the Ba-based ferrite used in Example 1 was mixed with the obtained aromatic polyester in the same method and proportion. , Kneading, adjustment, and evaluation of physical properties were performed.

The results are shown in Table 1.

(Examples 6 to 8) Examples 1 to 3 were added to the polyesters synthesized in Examples 1 to 3.
The same Ba-based ferrite as used in 1. was mixed, kneaded, prepared, and evaluated in the ratio of 3:17 by the same method.

The results are shown in Table 1.

(Comparative Example 1) Nylon-6, A1022LP (manufactured by Sekisui Plastics Co., Ltd.) and B
The a-type ferrite was kneaded in a weight ratio of 1: 9 in the same manner as in Example 1, pelletized, injection-molded in the same manner as in Example 1, and the physical properties were measured.

The results are shown in Table 1.

(Comparative Examples 2 and 3) As comparative examples, polyesters having the compositions shown in Table 1 were synthesized, and the same Ba-based ferrite was mixed, kneaded, adjusted and evaluated in the same manner and in the same proportion as in Example 1.

The results are shown in Table 1.

(Comparative Examples 4 to 6) The polymers used in Comparative Examples 1, 2, and 3, and Comparative Example 1,
Use the same Ba-based ferrite used in 2 and 3 in the same way.
Mixing, kneading, adjustment and evaluation were carried out at a ratio of 3:17.

The results are shown in Table 1.

(Example 9) An aromatic polyester was obtained by polymerizing in the same manner as in Example 1 except that the materials charged into the application container were as follows.
The system ferrite was mixed and molded, and the physical properties were evaluated.

The results are shown in Table 2.

p-acetoxybenzoic acid 6.66 mol (1200 g), m-acetoxybenzoic acid 0.334 mol (60 g), terephthalic acid 1.026
Mol (170.4 g), 2,6-naphthalenedicarboxylic acid 1.028 mol (222 g), 4,4'-diacetoxybiphenyl 2.056 mol (555 g) (Example 10) Other than the following materials to be charged into the application container, Polymerization was carried out in the same manner as in Example 9 to obtain an aromatic polyester.
The system ferrite was mixed and molded, and the physical properties were evaluated.

The results are shown in Table 2.

4.44 mol (800 g) of p-acetoxybenzoic acid, 0.334 mol (60 g) of m-acetoxybenzoic acid, 1.58 mol of terephthalic acid (262.5 g), 1.58 mol of 3,6-naphthalenedicarboxylic acid (3
42 g), 4,4'-diacetoxybiphenyl 3.17 mol (855
g) (Example 11) An aromatic polyester was obtained by polymerization in the same manner as in Example 9 except that the substances charged into the application container were as follows.
The system ferrite was mixed and molded, and the physical properties were evaluated.

The results are shown in Table 2.

7.215 mol (1300 g) p-acetoxybenzoic acid 0.334 mol (60 g) m-acetoxybenzoic acid, 0.887 mol (147.4 g) terephthalic acid, 0.889 mol (192 g) 2,6-naphthalenedicarboxylic acid, 4,4'-diacetoxy Biphenyl 1.778 mol (480 g) (Example 12) Polymerization was carried out in the same manner as in Example 9 except that the materials charged into the application container were changed to the following.
The system ferrite was mixed and molded, and the physical properties were evaluated.

The results are shown in Table 2.

7.215 mol (1300 g) p-acetoxybenzoic acid 0.361 mol (65 g) m-acetoxybenzoic acid, 0.445 mol (73.9 g) terephthalic acid, 1.78 mol (384.5 g) 2,6-naphthalenedicarboxylic acid, 4,4'-di Acetoxybiphenyl 2.225 mol (600.8 g) (Example 13) Polymerization was carried out in the same manner as in Example 9 except that the materials charged into the application container were as follows.
The system ferrite was mixed and molded, and the physical properties were evaluated.

The results are shown in Table 2.

7.215 mol (1300 g) p-acetoxybenzoic acid 0.361 mol (65 g) m-acetoxybenzoic acid, 1.503 mol (249.5 g) terephthalic acid, 0.722 mol (156 g) 2,6-naphthalenedicarboxylic acid, 4,4'-diacetoxy Biphenyl 2.225 mol (600.8 g) (Examples 14 to 16) The polyesters synthesized in Examples 9 to 11 were mixed with Examples 9 to 11
The same Ba-based ferrite as used in 1. was mixed, kneaded, adjusted, and evaluated in the ratio of 3:17 by the same method.

The results are shown in Table 2.

(Comparative Examples 7 and 8) As comparative examples, polyesters having the compositions shown in Table 2 were synthesized,
The same Ba-type ferrite was mixed, kneaded, adjusted, and evaluated in the same manner and in the same ratio as in Example 9.

The results are shown in Table 2.

(Comparative Examples 9 to 11) The polymers used in Comparative Examples 1, 7, and 8 and Comparative Example 1,
Use the same Ba-based ferrite used in 7 and 8 in the same way.
Mixing, kneading, adjustment and evaluation were carried out at a ratio of 3:17.

The results are shown in Table 2.

<Effects of the Invention> The plastic magnet composition of the present invention has higher heat resistance than conventional products and can be easily molded, so that the plastic magnet can be widely used for various purposes.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masafumi Komatsu 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Technical Research Headquarters (72) Inventor Yumiko Kumazawa 1 Kawasaki-cho, Chiba-shi Kawasaki Steel Co., Ltd. Research Headquarters (72) Inventor Nobu Yamagishi, Kawasaki-cho, Chiba City, Chiba Prefecture Kawasaki Steel Co., Ltd. Technical Research Headquarters

Claims (1)

[Claims] 1. Substantially each unit represented by the following formulas I, II, III, IV and V, V-O-Ar-O- (however, X in the formula is H, an alkyl group of _{C 1 ~C 4, C 1 ~C} 4
An alkoxy group, an aryl group or a halogen C ₆ -C _10, also, -O-Ar-O- is in the formula in symmetry dioxy unit having an aromatic ring of at least one monocyclic or condensed And Y is -O- or Is). Unit I 40 to 70 mol% Unit II 1 to 8 mol% Unit III + unit IV 6 to 36 mol% Unit V 10 to 40 mol% and the molar ratio of unit III / (unit III + unit IV) is 0.1 to
A plastic magnet composition comprising 100 to 1900 parts by weight of a powdery magnetic material with respect to 100 parts by weight of an aromatic polyester of 0.8.