JPH0730242B2 - Filling with metal powder, etc. Polycarbonate composition and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high specific gravity composition in which a metal powder or the like is filled in a high concentration and a method for producing the same, the product of which is, for example, an electrical product or an electronic product. Flywheel used for equipment,
It is used for a micromotor part.

(B) Conventional technology Iron powder or brass powder has a higher concentration than before (for example, a weight ratio of 70-80).
%) Is present in the flywheel, etc., and the composition containing iron oxide in a high concentration is magnetized during or after the injection molding process. It is used in micro motor parts.

Many of the plastic components to be mixed with such molding materials are polyamide resins (nylon 6, nylon 66,
Nylon 11, nylon 12, etc.) are used.

The reason for this is that in the above high-concentration blended product, the strength of the molded product is required, and in order to obtain good fluidity at the time of molding, it melts rapidly at a temperature above the melting point of the resin component. This is because a crystalline polymer having a reduced viscosity is preferable.

Of the crystalline polymers, nylon 6 is often used because of its cost, fluidity, strength of the composite system, and that it is not affected by deterioration due to metal.

However, a drawback of using nylon 6 is that it retains high strength in a dry state because it has a high water absorption rate, but it gradually absorbs moisture in actual use and becomes equilibrium with moisture in the atmosphere. Tensile strength drops to less than half.

In addition, it is extremely difficult to manufacture a precise molded product because the size of the molded product changes with the moisture absorption over time. In order to improve such drawbacks, nylon 11 with a low water absorption rate,
Other polyamide resins such as nylon 12 may be used, but these materials are extremely expensive and difficult to apply to industrial parts that are used in large amounts.

Further, in the case of nylon resin, the degree of crystallinity increases after molding and dimensional change due to this also occurs, so that the dimensional stability of the molded product is not preferable.

The above-mentioned drawbacks of the conventional materials severely restrict the industrial adoption of this kind of material, and therefore, improvement of these drawbacks has been strongly demanded.

(C) Problems to be Solved by the Invention High-concentration compounded materials such as metal powder according to the prior art depend on nylon resin for the reasons described above, but have the serious drawbacks described above.

However, it can be easily expected that such a defect can be solved by changing to an amorphous material which has a low hygroscopic property.

However, it was virtually impossible in the prior art to actually use high performance amorphous materials such as polycarbonate resins. The reason is that the flowability of polycarbonate is poor, and the flowability necessary for obtaining a precise molded product could not be obtained, especially when metal powder was mixed in a high concentration.

For this reason, if the molding temperature is unavoidably increased, the polycarbonate is thermally decomposed, and the generated gas corrodes the molding machine cylinder and the mold.

Another reason why it is difficult to use the polycarbonate is that the strength of the molded article, especially the impact resistance, is significantly lowered by the high concentration of the metal powder. That is, the impact resistance of polycarbonate is essentially due to the ductile fracture behavior of the material.However, when a metal powder or the like is blended in a high concentration, ductile elongation is constrained and the material becomes brittle and breaks. is there.

Still another cause is that polycarbonate has a high notch sensitivity and is easily broken at the interface of metal powder or the like.

As a means for improving the above-mentioned drawbacks in the related art, the present inventor provides a high-strength compounded composition such as a metal powder having high strength and good dimensional accuracy by a novel composite material using a polycarbonate resin, and a method for producing the same. As a result of intensive research for the purpose of providing the present invention, the present invention has been completed.

(D) Means for Solving the Problems The constitution of the polycarbonate composition filled with metal powder and the method for producing the same according to the present invention will be described in detail below.

The composition according to the present invention is a metal powder or metal oxide powder surface-treated with a silane coupling agent or a zircoaluminate coupling agent 80 to 90 wt% polycarbonate resin 10 to 20 〃 ethylene-α olefin copolymer, ethylene-unsaturated It is composed of 0.5 to 10% by weight of at least one soft resin material selected from a carboxylic acid copolymer and a styrene-butadiene block copolymer.

As the metal powder used in the composition according to the present invention, reduced iron powder (crushed), atomized iron powder, sprayed copper powder, or the like is used for high specific gravity molded products such as flywheel molded products, for plastic magnets. Ferrite powder is used.

The requirement of the present invention is that the metal powder or the metal oxide powder is first surface-treated to improve the affinity with the resin. For this purpose, organosilane compounds such as γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N
-Phenyl-γ-aminopropyltrimethoxysilane,
A silane coupling agent such as γ-glycidoxypropyltrimethoxysilane, or a zircoaluminate coupling agent having an organic ligand such as carboxy, aliphatic or methacryloxy as an organic functional group can be used. Of these, the most effective ones are aliphatic zircoaluminate coupling agents.

It is particularly effective to add 0.001 to 1.0% by weight, preferably 0.01 to 0.1% by weight, of the coupling agent to the metal powder or the like.

If it is less than this, the effect is poor, and if it is more than this, the cost is increased but the effect is not improved.

The polycarbonate resin used in the present invention is generally a commercially available and easily available thermoplastic aromatic polycarbonate and is represented by the following general formula.

Typical examples are dihydric phenols such as 2.2-
It is obtained by the reaction of bis (4-hydroxyphenol) propane (bisphenol A) with a carbonate precursor such as phosgene. However, the present invention is not limited to the polycarbonate of the above composition, for example,
A copolyester obtained by reacting bisphenol A with isophthaloin dichloride and phosgene and having a carbonate bond and an ester bond in the chain is also included. Further, the polycarbonate used in the present invention includes a polymer alloy containing a polycarbonate as a main component. included. These improve the molding processability of the composition, or the environmental stress fracture resistance of the resulting molded article.

Such polymer alloys include polycarbonate-ABS, polycarbonate-MBS, polycarbonate-thermoplastic polyesters such as polycarbonate copolyesters such as polybutylene terephthalate and polyethylene terephthalate.

The polycarbonate used in the present invention is generally about 2
Those having an average molecular weight of 0.000 to about 200.000, preferably 25.000 to 100.000 give a composite having a balanced performance in terms of both mechanical strength and moldability.

The third element of the composition according to the present invention is at least one soft resin component selected from ethylene-α-olefin copolymers, ethylenically unsaturated carboxylic acid copolymers and styrene-butadiene block copolymers.

This component is useful for improving the adhesion between the surface-treated metal powder or metal oxide powder and the polycarbonate, reducing the notch sensitivity to the impact of the polycarbonate, and further improving the fluidity of the composite system during melting. Of.

The ethylene-α-olefin copolymer is an α-olefin having 4 or more carbon atoms in ethylene, that is, butene-1, hexene-.
1, a copolymer of octene-1 and the like in an amount of 5 to 20% by weight, which is coordinate-polymerized using a so-called Ziegler catalyst.

The ethylene unsaturated carboxylic acid copolymer is a copolymer obtained by copolymerizing ethylene with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic anhydride, crotonic acid or itaconic acid in an amount of 5 to 30% by weight, preferably 10 to 20% by weight. Is.
Also included are so-called ionomers, which are ion-bonded copolymers obtained by partially neutralizing the carboxyl groups of unsaturated carboxylic acids with metal ions.

The styrene-butadiene block copolymer is a conjugated diene in which the central block of a linear polymer is polymerized, such as butadiene, isoprene, or 1.3 pentadiene, and a vinyl aromatic compound polymerized at both ends, such as styrene, α-methylstyrene, vinyltoluene. It is a soft resin or elastomer having

This central component can be improved in heat resistance by hydrogenation based on a known technique, and is more effective in the practice of the present invention.

The blending amount of soft resin component is 0.5 to 20 in polycarbonate.
%, Preferably 2 to 10% by weight.

If the blending amount is less than this, there is no effect, and if the blending amount is more than this, the compatibility is poor and separation may occur to lower the strength of the composition.

If the melting point of this soft resin component is lower than the temperature at which the polycarbonate softens and begins to flow (a temperature slightly higher than the glass transition point of 140 ° C.), the soft resin component melts during mixing to form iron powder and the like and polymer powder. Since they are in close contact with each other, they have an advantage of exerting an auxiliary effect of preventing separation when handling the mixture.

Such soft resin components include crystalline polymers such as ethylene-alpha olefin copolymers, ethylene-unsaturated resin acid copolymers and their metal ion neutralized products.

In the composition according to the present invention, an antioxidant such as a phenolic antioxidant such as tetraester hindered phenol, tetrakis (2.4-di-t-butylphenol) -4.4'-biphenylene phosphite, etc. can be prepared by a conventional method. 0.01 to 5% by weight, preferably 0.1 to 2% by weight, of the phosphorus-based antioxidant and the like can be mixed to prevent thermal deterioration during molding and actual use.

Furthermore, in order to control the material deterioration due to excessive shear heat generation during the plasticizing and kneading step and to improve the mold releasability of the molded product from the mold, a lubricant or a mold release agent should be added to this composition. Can be done.

For this purpose, for example, a lubricant such as stearic acid, methylenebis stearoamide, montanic acid wax, low molecular weight polyethylene, etc. is added in an amount of 0.01 to 2% by weight based on the composition.
It is effective to set it to preferably 0.05 to 0.5% by weight.

Further, depending on the required performance of the product using the composition, a lubricant such as silicon oil, graphite, molybdenum disulfide, polytetrafluoroethylene powder, and an anti-friction agent may be added to the composition in an amount of 0.1%.
-20% by weight, preferably 2-10% by weight.

The composition according to the present invention is melt-kneaded by a conventional method such as a single-screw extruder, a twin-screw extruder, and an extruder equipped with a kneading mechanism to form pellets, and then an injection molding machine is used by a conventional method. Can be molded.

As another means for carrying out the method for producing the composition according to the present invention, the composition is mixed at high speed with a high-speed mixer such as a Henschel mixer, and the soft resin component in the composition is melted by friction heat generation to obtain metal powder or the like. A method for producing a metal powder or metal oxide high-concentration filled plastic molded product by uniformly mixing and polycarbonate powder to form a mixture that is in intimate contact, melt-mixing this with an injection molding machine, and injection molding Is.

In carrying out this method, a normal screw in-line type injection molding machine can be used, but a structure having a screw with a dispersing function, for example, a pin type or a gear type structure can also give a better effect.

Further, the mechanism described in Japanese Patent No. 1104727, that is, the injection molding machine, is provided with a kneading mechanism in which a gap to the extent that shear shear is performed is formed between the inner surface of the screw flight top cylinder and the molding machine. It is also possible to obtain extremely good results.

Incidentally, in the injection molding of the composition according to the present invention, a material supply device that operates in conjunction with the screw of the injection molding machine is attached, and the material is adjusted to be supplied in a starved state into the cylinder of the molding machine. That is, it is preferable to mold.

This effect is that the material is sufficiently degassed and that the high viscosity material in the melting process does not hinder the advance of the screw during injection. This is because the smooth advance according to the combination of the position and the injection speed is extremely effective for manufacturing a precision molded product.

However, the composition itself according to the present invention is of course not restricted by this production method.

(E) Action The present invention has a high concentration of metal powder or metal oxide powder, which has been surface-treated with a coupling agent and has improved affinity with a polycarbonate resin, and has a high strength and a dimensional accuracy even at high temperature. By blending a good polycarbonate resin of, and further a specific soft resin component, the adhesion between the surface-treated metal powder and the polycarbonate resin is improved, the impact resistance of the composition is improved, and the composite material during melting is improved. It is a product that has improved flowability, etc., and has an excellent performance composition due to a well-balanced action by mixing an appropriate amount of each component. Furthermore, a molded product with high dimensional accuracy of the composition and less variation in specific gravity can be efficiently produced. It also developed a good manufacturing method.

(F) Example Hereinafter, the configuration of the present invention will be specifically described with reference to an example.

Example 1 (1) While mixing 5000 g of iron powder (KIP300A manufactured by Kawasaki Steel Co., Ltd., specific gravity 7.85) with an average particle size of 200 mesh produced by the atomization method at a low speed in a high-speed mixer (Kawata Seisakusho super mixer), zirco aluminum. Nate coupling agent (CA
VDON CHEM CAVCO MOD F) 25g and denatured alcohol 1
25 g of the mixed solution was added, and mixing was continued at 750 r / m for 30 minutes, and the temperature was raised to 100 ° C. to evaporate the alcohol content to obtain a treated iron powder.

(2) 702 g of powdered polycarbonate resin (Panlite L1250W manufactured by Teijin Chemicals Co., Ltd., average particle size 60 mesh), 62.5 g of ethylene-α olefin copolymer (Toughmer P0208 manufactured by Mitsui Petrochemical Co., Ltd.), hindered phenolic antioxidant ( ADEKA ARGUS AO-60) 3.5g was added, 750r
Mixed for 30 minutes at / m. The temperature of the mixture rises to 150 ° C,
The ethylene-alpha olefin copolymer melted.

(3) Continue cooling the jacket of the mixer with water to 100r
The mixing was continued at / m for 20 minutes to obtain a granular mixture in which iron powder and polycarbonate powder were fused.

(4) This mixture was put into an injection molding machine equipped with the melt kneading mechanism described in Japanese Patent No. 1104727 so that the supply part in the cylinder of the molding machine was starved from the screw feeder interlocking with the screw. It was supplied and molded.

Comparative Example 1 The same compounding and compounding procedure as in Example 1 was followed, except that the ethylene-α-olefin copolymer was not compounded and the polycarbonate was 1187.5.
The mixture was made up to g. This mixture was melt-kneaded at a cylinder temperature of 350 ° C. with a 35 mm diameter single-screw extruder to give pellets. The obtained pellets were molded by a normal injection molding machine (Niigata Iron Works SN76A).

Comparative Example 1-2 The mixture was molded by an injection molding machine (Niigata Iron Works SN76A). The cylinder temperature is 350 ° C.

Comparative Example 1-3 The mixture was molded by an injection molding machine equipped with the melt kneading mechanism described in Japanese Patent No. 1104727.

Comparative Example 1-4 The mixture was adjusted in an injection molding machine equipped with the melt kneading mechanism described in Japanese Patent No. 1104727 while adjusting the cylinder feed part from a screw feeder interlocking with the screw so that the cylinder feed part was kept starved. It was supplied and molded.

The results of injection molding of Example 1 and Comparative Examples 1-1 to 1-4 are shown in Table 1.

As the mold, an ASTM D638 type 4 tensile test piece was used.

The tensile strength and the specific gravity of the obtained molded product are shown in Table 2.

Incidentally, 50 samples were continuously molded, and the tensile strength was measured for any 5 pieces and the specific gravity for 10 pieces.

The test results are shown in Tables 1 and 2.

Comparative Example 5 (1) 4700 g of iron powder (KIP300A made by Kawasaki Steel Co., Ltd., specific gravity 7.85) with an average particle size of 200 mesh produced by the atomization method was used in a high-speed mixer (Super mixer made by Kawada Iron Works Co., Ltd.),
25 g of silane coupling agent (KBM603 manufactured by Shin-Etsu Chemical Co., Ltd. was diluted 10 times with denatured ethyl alcohol / water = 9/1 solution) was added, and mixing was continued for 30 minutes at 750 r / m to evaporate the alcohol content. A treated iron powder was obtained.

(2) Continue to powder nylon 6 resin (1011 manufactured by Ube Industries)
F) 675 g, O, P-toluenesulfonamide mixture (Fujiamide Chemical Co., Topsizer No. 5) 68 g, methylene bisamide (Harima Kasei Co., Ltd. Van Robe N18P) 25 g, soluble 8-nylon 15% alcohol solution (lead market) Company EM1
5) 500 g was added and mixed at 500 r / m for 5 minutes. The mixture was dried with a hot air dryer at 80 ° C. for 2 hours and then vacuum dried at 100 ° C. for 4 hours to obtain a granular mixture.

(3) The mixture of Example 1 and the mixture of Comparative Example 2 are described in Patent No. 11
Injection molding was carried out using an injection molding machine equipped with a kneading mechanism described in No. 04727, and supplying a material from a screw feeder linked with a screw of the injection molding machine so that the cylinder feed section of the molding machine was kept starved.

(4) Physical property test Using an injection molding machine, ASTM D638 type 4 tensile test piece (thickness 3.2m
m) and ASTM D790 bending test piece (5 "x 1/2" x 1/8 "
(Thickness) mold was attached and a test piece was molded. The molding conditions are shown in Table 3.

The material of Example 1 was adjusted to 23 ° C. and 50% RH, and then Comparative Example 2
The material was measured in an absolutely dry state immediately after molding and after the condition was adjusted to 23 ° C and 50% RH.

The results are shown in Table 4.

(5) Dimensional accuracy test The same injection molding machine as in (3) was used, and the die used was a disc shape with a pin hole (2.5 mmφ) in the center, a diameter of 47 mmφ, and an average wall thickness of 6.0 mm. The gate is a three-point pin gate symmetrically arranged in the center. Any 10 in 50 shot continuous molding
Table 5 shows the measurement results.

The measurement was performed after conditioning the molded product at 23 ° C. and 50% RH. Example 1 is much more excellent in dimensional accuracy than Comparative Example 2.

(G) Effect of the Invention The present invention has a serious drawback of the polyamide resin composition, which has been conventionally exclusively used as a resin composition for high-concentration filling of metal powder or the like, that is, the hygroscopicity or the change in crystallinity. In order to solve the deformation over time, as the main resin, it has a low hygroscopic property and is amorphous, but conventionally it has poor fluidity, and in particular obtains a precise molded product filled with metal powder at a high concentration. It was impossible to use polycarbonate resin,
We succeeded in developing a new composition that is moldable and has excellent strength and dimensional accuracy by pretreatment of metal powder and the like, and by appropriately blending a specific soft resin component, etc. We have also completed an efficient manufacturing method for products.

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Claims (9)

[Claims] 1. 80 to 90% by weight of a metal powder or a metal oxide powder surface-treated with a silane coupling agent or a zircoaluminate coupling agent, and a polycarbonate resin 10
~ 20 wt%, and ethylene-alpha olefin copolymer,
A metal powder highly concentrated plastic composition comprising 0.5 to 10% by weight of at least one soft resin selected from ethylene-unsaturated carboxylic acid copolymer and styrene-butadiene block copolymer. 2. The composition according to claim 1, wherein the metal powder is iron powder, copper powder or brass powder. 3. The composition according to claim 1, wherein the metal oxide powder is iron oxide powder. 4. The composition according to claim 1, wherein the α-olefin is an α-olefin having 4 or more carbon atoms. 5. The composition according to claim 1, wherein the ethylene-unsaturated carboxylic acid copolymer is an ionic bond type copolymer in which a carboxyl group is neutralized with a metal ion. 6. A composition according to claim 1, wherein the styrene-butadiene block copolymer is a styrene-butadiene block copolymer saturated by hydrogenation of polybutadiene blocks. 7. 80 to 90% by weight of a metal powder or a metal oxide powder surface-treated with a silane coupling agent or a zircoaluminate coupling agent, and a polycarbonate resin 10
~ 20 wt%, and ethylene-alpha olefin copolymer,
A powder mixture is screw-inlined during the production of a metal powder highly filled plastic composition composed of 0.5 to 10% by weight of at least one soft resin selected from ethylene-unsaturated carboxylic acid copolymer and styrene-butadiene block copolymer. 1. A method for producing a high-concentration filled plastic composition such as metal powder, which is characterized in that it is formed by an injection molding machine. 8. The injection molding machine is a molding machine equipped with a kneading mechanism in which a gap is formed between the top of the screw flight and the inner surface of the cylinder such that shear shear occurs. A method for producing the composition according to claim 7. 9. The mixed material is supplied from a material supply device which operates in conjunction with a screw of an injection molding machine so that a feed portion of a cylinder of the molding machine is in a starvation state. A method for producing the described composition.