JP2790691B2 - Magnetic composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic material composition, and more specifically, it is remarkably excellent in impact resistance.
The present invention relates to a magnetic composition having excellent adhesive properties, heat resistance, water resistance, moldability, flexibility, and electrical properties.

(Conventional technology and its problems) A sheet-like molded product formed by injection molding or extrusion molding a composition obtained by mixing magnetic powder into various thermoplastic resins or rubbers has a magnetic property against metals such as iron and nickel. Utilizing it, stationery and electric appliances are widely used in fields such as various daily necessities. Above all, in applications such as magnet members used at low temperatures, such as magnet seals for refrigerator doors, and magnet members used at high temperatures, such as the magnets on the front panel of microwave ovens, use at low or high temperatures In these applications, excellent flexibility and water resistance are required, but among these, in applications such as magnet members for front panels of microwave ovens that are used under severe conditions, especially at high temperatures, extremely high Heat resistance is required.

The present applicant has developed a magnetic material composition comprising poly-4-methyl-1-pentene and a magnetic powder and has filed a patent application for the purpose of providing a magnetic material composition satisfying such requirements (Japanese Patent Application No. 63-266821).

The present invention has a high level of physical properties such as adhesion, heat resistance, water resistance, and moldability, and can be used for a wide range of applications. In addition to the above physical properties, if a composition having excellent impact resistance at room temperature or low temperature can be obtained, the idea that this magnetic material composition can be used more widely is obtained. The present invention has been achieved as a result of research for obtaining a magnetic material composition having the following.

(Object of the Invention) Accordingly, an object of the present invention is to provide a magnetic composition having excellent impact resistance at room temperature or low temperature, and excellent adhesiveness, heat resistance, water resistance, moldability, flexibility, and electrical properties. To provide things.

(Means for Solving the Problems) The present invention has been proposed to achieve the above-mentioned object, and is characterized in that a specific three-component polymer is blended in a specific ratio.

That is, according to the present invention, in a magnetic composition containing a resin component and a magnetic powder component, the weight ratio of the resin component to the magnetic powder component (resin component / magnetic powder component) is 80/20 to 5/95. The resin component comprises: (A) 40 to 80 parts by weight of poly 4-methyl-1-pentene; (B) 20 to 40 parts by weight of a propylene polymer; and (C) 0 to 20 parts by weight of a graft. A magnetic composition comprising a modified poly-4-methyl-1-pentene is provided.

(Description of a preferred embodiment of the present invention) In the present invention, poly-4-methyl-1-pentene (A) constituting the resin component is a homopolymer of 4-methyl-1-pentene or 4-methyl-1-pentene. Other α-olefins such as ethylene, propylene, 1-butene,
A copolymer with an α-olefin having 2 to 20 carbon atoms such as 1-hexene, 1-octene, 1-decene, 1-tetradecene, and 1-octadecene. It is a copolymer mainly containing 4-methyl-1-pentene as described above. Melt flow rate of poly 4-methyl-1-pentene (MFR, load: 5 kg, temperature: 260
C) is preferably 0.1 to 500 g / 10 min, more preferably
It is in the range of 0.5 to 150 g / 10 minutes.

In the present invention, the graft-modified poly-4-methyl-1-pentene used as the component (C) is the above-mentioned poly-4
-Methyl-1-pentene is grafted with an unsaturated carboxylic acid component or an unsaturated carboxylic acid derivative component as described below.

As the poly-4-methyl-1-pentene used as a raw material when preparing the graft-modified poly-4-methyl-1-pentene, the same 4-methyl-1-pentene polymer as described above can be used. Above all, intrinsic viscosity [η]
(Measured at 135 ° C in decalin solvent) is 0.5 to 25 d /
A 4-methyl-1-pentene polymer in the range of g is preferably used.

Graft-modified poly-4-methyl-1 used in the present invention
-Pentene has a substantially linear structure and does not have a three-dimensional crosslinked structure. This can be confirmed by the absence of a gel in the solution when the graft-modified poly 4-methyl-1-pentene is dissolved in an organic solvent such as p-xylene.

Graft-modified poly-4-methyl-1 used in the present invention
The pentene has a graft ratio of the unsaturated carboxylic acid component or the unsaturated carboxylic acid derivative component of usually 0.5 to 15% by weight, preferably 1 to 10% by weight, and
Intrinsic viscosity [η] (value measured at 135 ° C in decalin solvent)
Is usually in the range of 0.3 to 10 d / g, preferably 0.5 to 5 d / g.

Graft-modified poly-4-methyl-1 used in the present invention
Pentene further has a molecular weight distribution (Mw / Mn) of 1 to 8, a melting point of 170 to 245 ° C., a crystallinity of 1 to 45%, and a DSC parameter of 4.0 or less. Preferably, there is.

The molecular weight distribution (Mw / Mn) represented by the weight average molecular weight / number average molecular weight ratio of the graft-modified poly 4-methyl-1-pentene is measured by gel permeation chromatography (GPC).

That is, using o-dichlorobenzene as a solvent,
With respect to 100 parts by weight of the solvent, 0.04 parts by weight of the graft-modified poly 4-methyl-1-pentene (2,6-di-ter
t-butyl-p-cresol was converted to a graft-modified poly 4-
After adding 0.05 parts by weight to 100 parts by weight of methyl-1-pentene) to form a solution, the solution is passed through a filter having a roughness of 1 μm to remove insoluble matters such as dust. Thereafter, the molecular weight distribution (Mw / Mn) was measured using a GPC measuring apparatus in which the column temperature was set to 135 ° C. and the flow rate was set to 1.0 ml / min. M
The w / Mn ratio was determined on a polystyrene basis.

The melting point of the graft-modified poly 4-methyl-1-pentene (sample) is a value measured by a differential scanning calorimeter (DSC), and the melting point is measured as follows. That is, the sample was placed on a differential scanning calorimeter (du Pont990).
Mold), raise the temperature from room temperature at a rate of 20 ° C / min.
Conversely, when the temperature reaches ° C, the temperature is lowered at a rate of 20 ° C / min, temporarily lowered to 25 ° C, and then raised again at a rate of 20 ° C / min. The melting point of the sample is read from the melting peak value at this time (in many cases, a plurality of melting peaks appear, so in the present invention, the value on the high melting point side was adopted).

The crystallinity was measured by the following method.
That is, using the chart at the time of melting point measurement by DSC, the melting area of the measurement sample per unit amount (S)
And the melting area (So) on the recording paper corresponding to the melting energy (Po) per unit amount of indium as a control sample. The Po of indium is a known amount, and the melting energy (P) per unit amount of the crystal part of poly-4-methyl-1-pentene is also known as follows. Is determined by

In the formula, Po is 27 Joules / g (at 156 ± 0.5 ° C.), and P is 14
1.7 Joules / g. [FCFrank et al., Philosophical
Magazine, 4,200 (1959)] Further, the DSC parameter, which is a parameter of the composition distribution of the graft-modified poly-4-methyl-1-pentene, is obtained by measuring the melting area (S) of the measurement sample by DSC at the melting point (that is, the maximum peak). It is obtained by dividing by the peak height. Therefore, it is estimated that the smaller the DSC parameter, the sharper the DSC curve and the narrower the composition distribution.

Graft-modified poly-4-methyl-1 used in the present invention
The pentene is modified with an unsaturated carboxylic acid component or a derivative component of this unsaturated carboxylic acid. As the unsaturated carboxylic acid component, specifically, acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid,
Citraconic acid, crotonic acid, isocrotonic acid, nadic acid ^R (endosis-bicyclo [2,2,1] hept-5-ene-2,3-dicarboxylic acid) and the like are used, and a derivative component of an unsaturated carboxylic acid. Examples include acid halides, acid amides, acid imides, acid anhydrides, esters and the like.Specifically, maleenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidyl Maleate or the like is used.

Among these unsaturated carboxylic acids or derivatives of these unsaturated carboxylic acids, unsaturated dicarboxylic acids or acid anhydrides thereof are preferable, and particularly, maleic acid, nadic acid ^R
And unsaturated dicarboxylic anhydrides such as maleic anhydride and nadic anhydride.

Graft-modified poly-4-methyl-1 used in the present invention
-Pentene is, for example, dissolving poly 4-methyl-1-pentene in a solvent, adding an unsaturated carboxylic acid or a derivative thereof and a radical polymerization initiator to the obtained solution;
It can be obtained by a method of performing graft modification by heating (solution method).

The radical polymerization initiator is used in an amount of usually 0.001 to 1 part by weight, preferably 0.01 to 0.5 part by weight, based on 100 parts by weight of poly 4-methyl-1-pentene. When the denaturation reaction is carried out in a solution state, the solvent is usually used in an amount of 100 parts by weight based on 100 parts by weight of the poly-4-methyl-1-pentene.
To 100,000 parts by weight, preferably used in a proportion of 200 to 10,000 parts by weight, as the denaturation reaction conditions, the temperature is usually 100 to 250 ° C., preferably 110 to 200 ° C., the time is usually 15 to 600 minutes, Preferably 30 to 60
Minutes.

As the solvent used in the modification reaction, specifically, hexane, heptane, octane, decane, dodecane, tetradecane, aliphatic hydrocarbons such as kerosene, methylcyclopentane, cyclohexane, methylcyclohexane, cyclooctane, cyclohexane Alicyclic hydrocarbons such as dodecane, benzene, toluene, xylene, ethylbenzene, cumene, ethyltoluene, trimethylbenzene, cymene,
Aromatic hydrocarbons such as diisopropylbenzene; halogenated hydrocarbons such as chlorobenzene, bromobenzene, o-dichlorobenzene, carbon tetrachloride, trichloroethane, trichloroethylene, tetrachloroethane and tetrachloroethylene; Among these solvents, alkyl aromatic hydrocarbons are particularly preferably used.

Examples of the radical polymerization initiator used in the graft modification reaction include organic peroxides, specifically, alkyl peroxide, aryl peroxide,
Acyl peroxide, aroyl peroxide, ketone peroxide, peroxycarbonate, peroxycarboxylate, hydroperoxide and the like are used, and more specifically, the following compounds are used.

Examples of the alkyl peroxide include diisopropyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butylperoxy-hexyne-
3, aryl peroxides such as dicumyl peroxide; acyl peroxides such as dilauroyl peroxide; aroyl peroxides such as dibenzoyl peroxide; ketone peroxides such as methyl ethyl ketone hydroperoxide;
Hydroperoxides such as cyclohexanone peroxide include tert-butyl hydroperoxide, cumene hydroperoxide and the like. Among these organic peroxides, di-tert-butyl peroxide, 2,5
-Dimethyl-2,5-di-tert-butylperoxy-hexyne-3, dicumyl peroxide, dibenzoyl peroxide and the like are preferably used.

In performing the grafting reaction, the unsaturated carboxylic acid or unsaturated carboxylic acid derivative is preferably used in a proportion of 1 to 40 parts by weight based on 100 parts by weight of poly-4-methyl-1-pentene.

The propylene polymer used as the component (B) in the present invention refers to a homopolymer of propylene, or propylene and 30% by weight or less of one or more other α-olefins, for example, ethylene, 1-butene, 1-hexene, 4
Block or random copolymer with -methyl-1-pentene or the like, or propylene, ethylene and 5% by weight or less of a polyene component, for example, 5-ethylidene-2-norbornene or 5-methylene-2-norbornene or
It contains a multi-component copolymer with 1,4-hexadiene and usually has a melting point of 130 ° C. or more and a melt flow rate (MFR) of 0.1 to 80 g / 10 minutes (ASTM D 1238 L). Among them, a block copolymer of propylene and ethylene is preferred.

The resin component in the magnetic material composition of the present invention is such that the component (A) is 40 to 80 parts by weight, preferably 45 to 70 parts by weight.
Parts by weight, 20 to 40 parts by weight of component (B), preferably 22
To 35 parts by weight, and 0 to 20 parts by weight, preferably 0.5 to 10 parts by weight, of the component (C).

The resin component blended in such a ratio is mixed with a magnetic powder component described later in a ratio of 80/20 to 5/95, preferably 30/70 to 5/95 (resin component / magnetic powder component: weight ratio). By doing so, as described above, it is possible to obtain a magnetic material composition having excellent impact resistance and a good balance of adhesion, heat resistance, water resistance, moldability, flexibility, and electrical properties. .

As the magnetic powder component used in the present invention, an oxide of an iron group element generally called ferrite (represented by a molecular formula MFe ₃ O ₄ , wherein M represents iron and / or an iron group element) is used. Specifically, the following ferrite is used.

Mn-ferrite, Ni-ferrite, Zn-ferrite,
Furthermore, these solid solutions, Mn-Zn ferrite and Mn-
Zn-Fe ferrite, Ni-Zn ferrite, or Co-Fe
Ferrite, Ba-ferrite, Sr-ferrite, Mn-Mg
Formulas of rare-earth elements other than iron-group elements, such as ferrites with various properties added to these ferrites by adding trace amounts of oxides of various elements to these ferrites, such as Al-ferrite and Cr-ferrite, RFeO ₃ ( In the formula, R represents a rare earth element such as Tm, Lu, Yb, Er, Ho, Y, Nd, Sm, Eu, etc.) or a combination of iron group element oxides not containing iron, such as rare earth orthoferrite. Magnetic materials, etc.

It is desirable that the particle size of these magnetic powders is 0.5 to 10 μm, preferably 1 to 5 μm. In particular, when a magnetic powder having a particle size of 1 to 5 μm is used, the magnetic composition can be easily extruded.

The magnetic material composition according to the present invention comprises the above-mentioned resin component and magnetic powder component.In addition to these two components, if necessary, as a heat stabilizer, a copper halide compound, a metal soap, It may contain a lead stabilizer, an organic tin stabilizer, an epoxy compound, a bisphenol-based stabilizer, a phosphite-based stabilizer, and the like, and these may be used alone or as a mixture of two or more.

In addition, the heat stabilizer is based on 100 parts by weight of the resin composition.
Usually, it is used in a proportion of 0.1 to 5 parts by weight.

The magnetic material composition according to the present invention is obtained by adding a heat stabilizer, a lubricant, and the like to the above-described resin component and magnetic powder, if necessary, and blending using a Henschel mixer, a V-type blender, or the like. It is obtained by blending using a screw extruder or a multi-screw extruder.

(Effect of the Invention) The magnetic material composition according to the present invention is excellent in impact resistance and excellent in properties such as adhesiveness, heat resistance, water resistance, and moldability by being composed of the above components. ing.

The magnetic composition according to the present invention makes use of the above-mentioned excellent features, and is used for rotating magnets, copiers, sensors, automobile parts, toys, miscellaneous goods, plastic magnets used in microwave oven parts, and the like. It is preferably used.

(Examples) Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Preparation of graft-modified 4-methyl-1-pentene 4-methyl-1-pentene homopolymer (intrinsic viscosity [η] 1.7 dl / g, toluene solvent in the presence of dicumyl peroxide catalyst at a temperature of 145 ° C. _Mw / _Mn 7.5, melting point 241 ° C, crystallinity 42%, DSC parameter 3.0: hereinafter sometimes referred to as PMP (I)) were graft-polymerized with maleic anhydride.

A large excess amount of acetone was added to the solution containing the thus obtained graft polymer to precipitate the graft polymer.

This graft polymer is separated by filtration, and the separated graft polymer is repeatedly washed with acetone, and is subjected to maleic anhydride graft-modified poly-4-methyl-1-pentene A (hereinafter referred to as MAH-PMP (A). There is).

This maleic anhydride graft-modified poly-4-methyl-1
The graft ratio of maleic anhydride units in pentene A is 4.0% by weight, the intrinsic viscosity [η] is 0.95 dl / g, and the melting point is 210
° C, crystallinity 18%, _Mw / _Mn 4.5, DSC parameter 2.8
Met.

Ferrite which is a magnetic powder material (average particle diameter 1.18μ
m, compression density 3.25 g / cm ³ , OP.7, manufactured by Nippon Begara Kogyo Co., Ltd.
1) 100 parts by weight of surface treatment agent ("Blenact")
KR-TTS, manufactured by Ajinomoto Co., Inc.) in an amount of 1 part by weight,
The ferrite was previously surface-treated.

Examples 1 to 3 75 parts by weight of the above-mentioned PMP (1) and crystalline propylene /
Ethylene block copolymer (ethylene content: 20% by weight, M
FR: 0.5 g / 10 min, density: 0.91 g / cc) 20 parts by weight and the MAH-
PMP (A) 5 parts by weight of a resin composition (hereinafter referred to as modified P
MP-1) and the above ferrite in a weight ratio shown in Table 1.

2 parts by weight of Irganox 1010 (Ciba-Geigy) as a heat stabilizer with respect to 100 parts by weight of the modified PMP-1
Seanox 412S (Penta (erysryt
1 part by weight of hyl-tetra-β-mercapt laurs (propionate manufactured by Cipro Kasei Co., Ltd.).

Next, the compound comprising the modified PMP-1, ferrite and heat stabilizer was mixed with a Henschel mixer and pelletized with a twin-screw extruder. Next, using an injection molding machine, test specimens in the following items were prepared from the pellets, and measurement was performed for each item.

(1) Heat aging test: A square plate of 120 mm x 150 mm x 2 mmt was prepared, and then placed in an air oven set to an atmosphere of 160 ° C, left for 5 days, and the deterioration state and deformation of the test piece.
The molten state was visually observed and evaluated.

(Evaluation method) ：: No problem with deterioration, deformation, melting change △: Slight deterioration X: Notable deterioration, deformation and melting, (2) Boiling resistance test; Test specimen similar to the above (1) was prepared Then, the test piece (square plate) was immersed in boiling water at 100 ° C. for one day, and the dimensional property was measured.

(Evaluation method) ○: Dimensional change of less than 1.0% ×: Dimensional change of 1.0% or more (3) Izod impact strength: Izod impact test piece (with notch) was prepared using an injection molding machine, and was subjected to an atmosphere at 23 ° C. Was measured according to ASTM D256.

(4) Tensile test: A test piece conforming to ASTM D638 was prepared using an injection molding machine, and the elongation was measured in an atmosphere at 23 ° C.

(5) Chemical resistance test; 20 mm from the square plate shown in (1) above
A test piece of × 40 mm × 2 mmt was cut and immersed in 98% sulfuric acid at a temperature of 25 ° C. for 7 days, and the weight change of the test piece was measured.

(Evaluation method) :: dimensional change of less than 1.0% ×: dimensional change of 1.0% or more Table 1 shows the obtained results.

Reference Example 1 4-methyl-1- with MFR of 0.5 g / 10 min (260 ° C, 5 kg load)
The same heat-resistant stabilizer as in Example 1 was added to 100 parts by weight of the pentene-decene copolymer (abbreviated as PMP-D), and the ferrite was blended in the amount shown in Table 1.

Next, the compound comprising PMP-D, ferrite and heat stabilizer was mixed with a Hensel mixer and pelletized with a twin screw extruder. Next, using an injection molding machine, test pieces similar to the test pieces in each test item of Example 1 were prepared from the pellets, and subjected to heat aging resistance, boiling water resistance, Izod impact strength, tensile test, and chemical resistance test. And other tests were performed by the method described in Example 1.

 Table 1 shows the obtained results.

Comparative Example 1 Nylon 6 having an MFR of 43 g / 10 minutes (235 ° C., 1 kg load)
The same heat-resistant stabilizer as in Example 1 was added to 100 parts by weight (A1020BRL grade, manufactured by Unitika Ltd.), and the above ferrite was blended in the amount shown in Table 1.

Next, a blend comprising nylon, ferrite and heat stabilizer was mixed with a Hensel mixer and pelletized with a twin screw extruder. Next, using an injection molding machine, test pieces in each test item of Example 1 were prepared from the pellets,
The procedure was as described in Example 1.

 Table 1 shows the obtained results.

Comparative Example 2 The same amount of the same heat-resistant stabilizer as in Comparative Example 1 was added to 100 parts by weight of polypropylene, and the above ferrite was blended in the amount shown in Table 1.

Next, a mixture of polypropylene, ferrite, and a heat stabilizer was mixed in the same manner as in Comparative Example 2, and a test piece for each test item described in Example 1 was prepared using the same injection molding machine. The test was carried out according to the method described.

 Table 1 shows the obtained results.

Claims (1)

(57) [Claims] 1. A magnetic composition comprising a resin component and a magnetic powder component, wherein the weight ratio of the resin component to the magnetic powder component (resin component / magnetic powder component) is 80/20 to 5/95, The resin components are (A) 40 to 80 parts by weight of poly-4-methyl-1-pentene, (B) 20 to 40 parts by weight of a propylene polymer, and (C) 0 to 20 parts by weight of graft-modified poly4. A magnetic material composition comprising -methyl-1-pentene.