JPH0462007A - Resin composite material blended with ferromagnetic metallic powder and manufacture thereof - Google Patents

Abstract

PURPOSE:To enhance the melt fluidity of resin blended with ferromagnetic metallic powder and enable pin gate molding and hot-runner molding by a method wherein the ferromagnetic metallic powder, whose surface is uniformly coated with the thin film of an inorganic phosphate metallic compound containing no organic group and is treated with an isocyanate compound, is blended with resin. CONSTITUTION:Ferromagnetic metallic powder is formed into ultrafine powder of 10mum, or of not more than 1mum as necessary, in average particle size and, while being stirred together with a powdering assistant, the powder is subjected to the application of phosphate coatings on the surface thereof by introducing a coating treating agent, in which a phosphoric acid and alcoholes are mixed with each other, in the atmosphere of active gas. The ferromagnetic metallic powder, to which the phosphate coating treatment is applied, is introduced into a universal blender or into a mixer and, while the blender or the mixer is being rotated continuously at a low speed of 2-10 rpm, an isocyanate compound dissolved in a solvent in advance is added to and mixed with said powder. After mixing the powder with the isocyanate compound at a low speed for about one hour, it is dried. The dried ferromagnetic metallic powder is blended with a resin material such as a synthetic resin or a synthetic rubber in 5-96wt.% amount to the amount of the resin material and is kneaded under heating.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to the production of ferromagnetic metal powder that is kneaded with a resin material and formed into a pellet or sheet semi-finished product, or injection molded into a product. The present invention relates to a resin composite material for so-called plastic magnets containing the same, and a method for producing the same.

(Background Art) Ferromagnetic metal powder is blended with resin, heated and kneaded, molded into pellets or sheet products, or injection molded to form a product, and then magnetized to make a magnetized product. Generally practiced.

In this case, it is difficult to mix the ferromagnetic metal powder and resin evenly and to form a strong bond between the two materials, and the material has poor fluidity during molding.To counter this, the molding temperature is raised to make it flow easier. However, even then, it could not be used for pin gate formation where the gate is extremely small or hot runner molding where the fluidity of the resin is controlled by a portion of the runner.

Furthermore, when the molding temperature is raised, there is a problem in that the material is locally heated to a temperature that exceeds the heat resistance temperature of the metal powder, and the metal powder is oxidized and the magnetic properties of the product are impaired.

(Problems to be Solved) In the process of researching the moldability of resin materials blended with ferromagnetic metal powder, the present inventors coated ferromagnetic metal powder with phosphoric acid and surface-treated it with an isocyanate compound. It has been found that the fluidity of the resin is specifically improved when

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a resin composite material that improves the melt fluidity of a resin blended with ferromagnetic metal powder and is capable of pin gate molding and hot runner molding, and a method for producing the same.

(Structure) The present invention is characterized in that a ferromagnetic metal powder whose surface is uniformly covered with a thin film of an inorganic phosphate metal compound containing no organic group and whose surface is treated with an isocyanate compound is blended into a resin. It is a resin composite material.

Further, in the present invention, a ferromagnetic metal powder whose surface is covered with an inorganic phosphate metal compound that does not contain an organic group is surface-treated by mixing an isocyanate compound, and the surface-treated ferromagnetic metal powder is blended with a resin and kneaded by heating. This is a method for producing a resin composite material containing ferromagnetic metal powder, which is characterized by molding.

(Function) A resin composite material containing ferromagnetic metal powder can specifically improve the flow of molten resin only when the metal powder is coated with phosphoric acid using inorganic phosphoric acid that does not contain organic groups, and the surface is treated with an isocyanate compound. Improves sex.

This means that even if the ferromagnetic metal powder is surface-treated with an isocyanate compound, the ferromagnetic metal powder is not coated with phosphoric acid in advance, or even if the ferromagnetic metal powder is coated with phosphoric acid, other surface treatments may be applied. When the surface was treated with a chemical agent, the properties of the lateral bottom were not expected to improve.

(Effects) The melt fluidity of the resin blended with ferromagnetic metal powder was significantly improved, making pin gate molding and hot runner molding possible.

(Example) In this application, "ferromagnetic metal powder" refers to ferromagnetic alloy powder such as RCos, RCOI7 (R is Sm).

Rare earth elements such as Pr, Ce, La, etc.), Nd-Fe-B-
Includes Co-based alloy powder, alnico alloy powder, ferromagnetic metal iron powder, etc. "Phosphoric acid" includes not only phosphoric acid (Hspo), but also inorganic phosphorus groups and other inorganic phosphorus compounds.

The ferromagnetic metal powder is finely pulverized by a known method or by the method disclosed in Japanese Patent Application Laid-Open No. 1-234502 previously proposed by the inventor to form an ultrafine powder with an average particle size of 10 μm and, if desired, 1 μm or less.

While stirring the pulverized ferromagnetic metal powder together with a grinding aid, a coating agent containing a mixture of phosphoric acid and alcohol is added to coat the metal powder surface with phosphoric acid in an active gas atmosphere. do.

The above-mentioned coating treatment agent suppresses esterification of phosphoric acid as much as possible by quickly stirring and mixing the required amount of phosphoric acid with an alcoholic solvent immediately before the metal particles are crushed to the desired particle size and coated. It is something.

If the coating treatment agent is left for a long time, phosphoric acid esterification progresses, and the heat resistance of the treated metal fine powder decreases accordingly.

If the metal powder is used at temperatures ranging from room temperature to about 200° C., even fine metal powder treated with a coating treatment agent that is highly esterified will exhibit sufficient oxidation resistance. However, for use in plastic magnets that are kneaded with resin and molded at high temperatures of 200°C or higher, ferromagnetic metal powder is treated with a liquid that avoids phosphoric acid esterification as described above to form a thin film of an inorganic phosphate metal compound. Must be used covered.

If phosphoric acid is in excess of the metal fine powder, the residual phosphoric acid in the treatment solution will react with the alcohol solvent during the drying process after surface treatment, resulting in esterification, which will have an adhesive effect and cause the metal fine powder to react. The powder layer solidifies or adheres firmly to containers being handled, making cleaning of equipment and containers difficult. Therefore, the amount of phosphoric acid to be added must be strictly defined according to the amount of ferromagnetic metal powder to be treated and the average particle size, and the amount of alcohol solvent to dissolve this phosphoric acid must also be determined according to the amount necessary to uniformly disperse the phosphoric acid. It is important to limit it to a minimum.

In general, phosphoric acid has an average particle size of metal powder of around 10 microns, and the weight of phosphoric acid is 0.4 to 1.0 microns relative to the weight of ferromagnetic metal powder.
% (particularly 0.6 to 0.08%), the best oxidation-resistant film can be obtained.

This avoids the troubles associated with esterification of phosphoric acid, and instead of being dry and having extremely good fluidity, a phosphoric acid-based metal compound that is close to a monomolecular layer is formed on the surface of the fine metal powder. The magnetic properties can be improved.

Next, the above-mentioned ferromagnetic metal powder coated with phosphoric acid is brought into contact with an isocyanate compound for surface treatment.

The isocyanate compound includes (1) RゎS i (NGO), an alkyl or phenyldilyl triisocyanate represented by -7 (in the formula n
represents an integer from 1 to 3. R represents an alkyl group, a halogen-substituted alkyl group, a vinyl group, or a phenyl group. ) (2) An isocyanate-functional silane coupling agent represented by any of the following formulas.

(CHiO)is i -CH2CH2CH2-NCO
.

(CH2CH20)sS i CHt'CH*CHt
NGO.

(CHsO)icHss l CH2CH2CH
x-NCO.

(CHICH5o)2CHsS i -CH2CH2
CH*-NCO.

It is one kind or a mixture of two or more kinds selected from the above groups (1) and (2).

0.0 parts of an isocyanate compound as a surface treatment agent is added to 100 parts by weight of the ferromagnetic metal powder coated with phosphoric acid.
Use 1 to 2 parts.

The isocyanate compound can be used as such, but it may also be diluted with an organic solvent. The organic solvent is hexane,
n-butane, petroleum hydrocarbon, toluene, xylene, 1
．． 11 trichloroethane, acetone, dioxysan, diglyme, ethyl acetate, butyl acetate, cellosolve, acetate, etc. can be used.

Alcohols such as methanol can also be used, although they are less stable.

The treatment method is to put the above-mentioned ferromagnetic metal powder coated with phosphoric acid in advance into a universal mixer or mixer, and heat it for 2 to 10 r.
While continuing to rotate at a low speed of pm, an isocyanate compound previously dissolved in a solvent is added and mixed.

After mixing at low speed for about 1 hour, dry. In this case, it is possible to forcefully exhaust the air using a vacuum pump.

The dried ferromagnetic metal powder is mixed with 5 to 96% by weight of a resin material such as synthetic resin or synthetic rubber, and then heated and kneaded.

After kneading, the mixture is extruded using an extruder to form a pellet for injection molding, or a heated roller is used to form a sheet-like semi-finished product. Alternatively, the mixture is kneaded and extruded into a predetermined shape using a kneading extruder. It goes without saying that the molding method is not limited to the one described above, and other molding methods can be employed.

(Comparative Experimental Example) A comparative example in which injection molding was performed using a resin compounded material containing ferromagnetic metal powder with or without coating treatment of ferromagnetic metal powder, surface treatment, and various surface treatment agents will be shown below.

Raw material powder manufacturing procedure Nd-based rare earth magnet alloy raw material powder having a composition of Nd 12F e ysc O4Bs in atomic weight % (rMQP-BJ average particle size 25 μm manufactured by General Motors) 500
Weigh gr.

In advance, 3 kg of steel balls and an organic solvent n as a grinding aid were placed in a stirring tank.
- After charging a mixed solution of 300 gr of hexane and 100 gr of toluene and the above raw material powder, the stirring tank is sealed.

N2 gas (purity 99.9% or higher) is injected into the stirring tank from the gas supply pipe at a flow rate of 2/min to purge the air in the tank for about 5 minutes.

After the N2 gas replacement was completed, the stirring motor was started and wet pulverization was performed for 9 minutes at a rotation speed of 205 rpm until the average particle size was 1.
A fine grind of 1.7 μm is obtained.

Before this fine pulverization, the phosphoric acid solution is adjusted. That is, 4g of orthophosphoric acid is weighed and dissolved in 40g of methanol and stirred for about 5 minutes using a stirrer to prepare a uniform phosphoric acid alcohol solution. Pour this surface treatment liquid into the treatment liquid tank, replace the inside of the treatment liquid tank with N, and then
When the above-mentioned pulverization is completed, the injection valve of the stirring tank is opened and the injection is completed within a few seconds while applying N and pressure (1.6Kg/c+o”).Meanwhile, the stirring rod continues to rotate at the same number of revolutions after pulverization. (205 rpm) to stir and disperse the treatment liquid, and after 30 seconds, the rotation is stopped to complete the coating treatment.

Next, open the lid, take out the lid plate and stirring rod together, and then put the coated fine powder, steel balls, and liquid into a container with a stainless steel wire mesh attached. After removing all the particles, the fine powder precipitated in the receiver was transferred to a drying vat, and after removing the supernatant liquid, it was placed in a dryer equipped with an exhaust fan and dried by heating at 50 to 70°C for about 3 hours. A fine Nd-based rare earth magnet alloy powder exhibiting a purple color is obtained.

Manufacturing procedure for Comparative Examples 2 to 4 1) Accurately weigh 250 g of raw material ferromagnetic metal powder that has not been coated with phosphoric acid according to the formulation shown in Table 1 using an electronic balance.

2) For 250g (100 parts) of this raw material powder,
2 g (0.8 parts) of the surface treatment agent are mixed with the solvent previously prepared in a beaker using a stirrer for 3 minutes. The solvent to be used depends on the surface treatment agent used, as shown in the table below.

Mix the coupling agent mixed with the solvent with the raw materials in a mortar (approximately 3 ml).

Or, if the amount to be processed is 3 kg or more, use a universal mixer (
ACM5L manufactured by Ukedamasha is used.

3) The raw materials subjected to the coupling treatment in 2) are spread in a vat and dried in an oven at 100°C for the S-320 treatment made by Chisso Corporation, and at about 70°C for the other coupling agents for about 1 hour. Alternatively, use a multipurpose mixer to heat and vacuum dry at the same temperature settings.

4) The coupling-treated raw materials dried in step 3) are mixed with nylon 12 (P3 manufactured by Ube Industries Ltd.) again in a mortar or all-purpose mixer.
Mix well with a resin binder such as 014U (approximately 5 m
1n).

5) Precisely weigh 250g of the mixed powder mixed in 4), and use a Toyo Seiki Laboplastomill at a setting of 250°C for approximately 5 wi
knead. The resulting sticky compound is made into pellets with a diameter of 2 to 3 mm using a cutter.

6) Repeat the steps up to 5) above 4 times to make compound pellets with a total weight of IKg.

7) Use an injection molding machine (manufactured by Kanto Seiki Kogyo) to mold the pellets into φ10x7 (round), 10xlOx7 (square), 7
Three types of test pieces of 5x13x3 (plates) were made and used as samples for measuring various physical properties.

Comparative Examples 5 and 7 1) Phosphoric acid coated powder 2 according to the formulation in Table 1
Accurately weigh 50g using an electronic balance.

2) For 250g (100 parts) of this powder, add 2g (0
, 8 parts) of the surface treatment agent were subjected to coupling treatment under the same conditions as described in Comparative Examples 2 to 4, and nylon was mixed and kneaded to produce a nylon resin composite material composition.

Comparative Example 6 (Si-310+MBS-88) 2 as a surface treatment agent
Use a mixture of different types. Other than this, the coupling treatment was performed under the same conditions as described in Comparative Examples 2 to 4, and nylon was mixed and kneaded to produce a nylon resin composite material composition.

Invention 8.10 1) Phosphoric acid coated powder 2 according to the formulation in Table 1
Accurately weigh 50g using an electronic balance.

2) The coupling agent used is r5i-310 parts manufactured by Matsumoto Pharmaceutical Co., Ltd. Other than this, the coupling treatment was performed under the same conditions as described in Comparative Examples 2 to 4, and nylon was mixed and kneaded to produce a nylon resin composite material composition.

3) In Invention 10, since the ferromagnetic raw material powder was used for an Sm-Co-based anisotropic magnet, injection molding was performed in an orientation magnetic field of 90,000e to produce an anisotropic magnet.

Comparative Example 9 1) After thoroughly mixing nylon 12 and raw material powder in a mortar or universal mixer (approximately 5 ml) without performing any phosphoric acid coating or surface treatment on Sm-Co raw material powder, Comparative Example 2 ~
The mixture was kneaded under the same conditions as described in Section 4 to produce a nylon resin composite material composition.

2) Thereafter, molding is performed under the same conditions as described in Invention 10,
It was made into an anisotropic magnet.

(Hereinafter, blank space) The method for molding a resin composite material according to the present invention involves mixing pellets (hereinafter referred to as a compound) kneaded by the above method,
It was melted and injection molded using the following injection molding machine. A cylindrical test piece with a diameter of 10 mm and a length of 7 mm is used to evaluate corrosion resistance, a 10 x 10 x 7 square test piece is used to measure magnetic properties, and a 5 x 13 x 3 plate test piece is used to measure bending strength, flexural modulus, and IZOD impact strength. It was used as a test piece.

For the evaluation of thermal stability, a Labo Blast Mill 50C150 manufactured by Toyo Seiki Seisakusho (manufactured by Toyo Seiki Seisakusho) was used. The test conditions were as follows: 50 cm" (weight: 250 g) of the substance was weighed,
Heat it to ℃ and place it in the test chamber of a laboratory blast mill. Changes in the torque value of the melt were measured using an R-60 blade at a rotation speed of 50 rpm for 20 minutes under heating at 280°C. This measurement shows that the higher the torque value, the higher the viscosity of the melt and the worse the fluidity.

Interference conditions: Toyo Seiki Lab Blast Mill 50C150
A total of I Kg of compound was produced in 250 g/l batches using a mold machine (capacity +60 cm”).

At a set temperature of 250° C. and a crosstalk time of 5 min, the resulting rice cake-like lump was reduced to a pellet shape (particle size of 5 mm or less) and used as a molding sample.

Molding conditions 1) Molding machine: Kanto Seiki Kogyo mold clamping force 30to
n KS-3OA Injection amount 45 cm' 2) Molding temperature: 260℃-310℃ 3) Injection pressure 1200 Kgf/cm'' 4) Molding cycle: 30sec 5) Orienting magnetic field: 9000 0e Magnetic property measurement conditions 1) Nippon Dengen 2) B-H Curve Tracer Model 5501 manufactured by Side Mold 3) Measurement applied magnetic field: 250000e (7mm gap) (blank below) In addition, Samples 8 and 10, which correspond to the practice of the present invention, showed excellent corrosion resistance in the salt water immersion test. It shows.

This is because the compatibility between the nylon resin and the metal powder is very good, as can be seen from the fluidity rate (melt flow value) at 270°C, and the metal surface is well covered with the resin, so the resin acts as a barrier. This is thought to improve corrosion resistance, and therefore the effects of the present invention are significant.

[Brief explanation of drawings]

FIGS. 1 and 2 are graphs showing changes in torque over time when samples 1 to 10 in a molten state were kneaded. Effects of the Invention Regarding corrosion resistance, H indicates time, O indicates good, and Δ indicates slight corrosion. × indicates not possible. In addition, when there is no increase in torque and the thermal stability is stable, it is indicated by "-". As is clear from the above test results, Samples 8 and 10, which correspond to the implementation of the present invention, can be molded at a molding temperature of 280°C, and the fluidity (melt flow value) at 270°C is significantly higher than that of other samples. It can be seen that it has been improved. Further, as shown in FIGS. 1 and 2, the torque change during melting of Samples 8 and 10 corresponding to the implementation of the present invention was 20
No increase in torque, that is, no tendency for increase in viscosity was observed even after minutes passed. That is, in the comparative examples other than Samples 8 and 1o of the present invention, when the external thermal energy and the shearing force by the R60 type blade continue to be applied, the torque increases, that is, the viscosity increases, and the fluidity is lost. It is clear that the thermal stability is poor. Although Sample 5 is located between the curves of Samples 4 and 6, the graph is omitted. Time (minutes) → Time (minutes) −

Claims (2)

[Claims] (1) A resin composite material characterized in that a ferromagnetic metal powder whose surface is uniformly covered with a thin film of an inorganic phosphate metal compound containing no organic groups and whose surface is treated with an isocyanate compound is blended into a resin. (2) ferromagnetic metal powder whose surface is covered with an inorganic phosphate metal compound that does not contain organic groups is mixed with an isocyanate compound for surface treatment, and the surface-treated ferromagnetic metal powder is blended with a resin and kneaded by heating; A method for producing a resin composite material containing ferromagnetic metal powder that can be molded.