JPS63256646A - Thermoplastic polyester resin composition filled with metallic powder or the like and production thereof - Google Patents

Abstract

PURPOSE:To provide the title compsn. which can be kept in the form of a granular mixture without causing separation during storage and transportation, has good mold release characteristics and gives products with high accuracy, consisting of a metallic (oxide) powder having a treated surface and a mixture obtd. by blending an arom. satd. thermoplastic polyester resin with a thermoplastic copolyester resin. CONSTITUTION:The title compsn. consists of 80-92wt.% metallic powder or metal oxide powder having a treated surface (e.g., iron powder having a surface treated with a zirconium aluminate coupling agent, etc.) and 8-20wt.% mixture of an arom. satd. thermoplastic polyester resin (e.g., polyethylene terephthalate, etc.) and a thermoplastic copolyester resin (e.g., a resin obtd. by co-condensing terephthalic acid with 20-50mol.% of a linear dibase) in a weight ratio of 99.9/0.1-90/10. The compsn. is in the form of a granular mixture, does not cause separation during storage and transportation, prevents cylinders from being worn by metallic powder, etc., does not cause lowering in mechanical strengths by thermal deterioration, can impart proper flexibility to molded products, has good mold release characteristics and is effective in improving the accuracy and strengths of products.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a high specific gravity composition filled with a high concentration of metal powder, etc., and a method for producing the same. Flywheels used in equipment, etc.
It is used for parts of micro motors, etc.

fb) Conventional technology Iron powder and brass powder are used at higher concentrations (e.g., weight ratio 70~
High specific gravity compositions containing iron oxide (80%) exist and are molded into parts such as flywheels by injection molding, and compositions containing high concentrations of iron oxide are magnetized during or after the injection molding process. It is used in parts of micro motors, etc.

The plastic components used in such molding materials are mostly polyamide resins (nylon 6, nylon 66).
, nylon IL nylon 12, etc.) are used.

However, the disadvantage of using nylon 6 is that the resin has a high water absorption rate, so although it maintains high strength in a dry state, it gradually absorbs moisture during actual use, and when it is in equilibrium with the moisture in the atmosphere, it retains high strength. The tensile strength decreases to less than half.

In order to improve these drawbacks, other polyamide 41 resins such as nylon 11 and nanolon 12, which have low water absorption rates, are sometimes used, but these materials are extremely expensive.
This method is difficult to apply to industrial parts that are used in large quantities.

In order to improve the drawbacks of using nylon resin,
Attempts have been made to use thermoplastic polyester resins, particularly polybutylene terephthalate, as the 41 fat component, but at present no satisfactory formulations have been obtained due to many difficulties, particularly in moldability. That is, in most of the current formulations, the blending ratio of metal powder is less than 80%, and the desired function cannot be fully exhibited.

If the proportion of the gold medal powder is 80% or more, especially 85% or more, the cylinder of the molding machine will be damaged and the mechanical strength of the molded product will be significantly reduced.

The above-mentioned drawbacks of conventional materials significantly restrict the industrial adoption of this type of material, and therefore there has been a strong demand for improvement of these drawbacks.

(C) Problems to be Solved by the Invention As mentioned above, compositions containing high concentrations of metal powder in the prior art have low strength when moisture is absorbed with polyamide resin, and high strength molded products can be obtained with polybutylene terephthalate resin. It was difficult.

This invention was made with the aim of improving the above-mentioned drawbacks of the prior art and developing a high-performance metal powder-filled composition with a high concentration, and this invention has been completed.

Means for Solving the TD1 Problem The structure of the thermoplastic polyester composition filled with metal powder etc. and the method for producing the same according to the present invention will be explained in detail below.

The composition according to the present invention consists of: 80 to 92% by weight of metal powder or metal oxide powder surface-treated with a silane coupling abrasion or zircoaluminate coupling agent; ■ Aromatic saturated thermoplastic polyester resin and thermoplastic copolyester resin. It is composed of 8 to 20% by weight of a 99.910.1 to 90/10% mixture of

As the metal powder used in the composition according to the present invention, reduced iron powder (pulverized), atomized iron powder, or atomized copper powder is used for high specific gravity molded products such as flywheel molded products.
For plastic magnets, oxides of iron group elements called ferrites are generally used.

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

The coupling agent is 0.001 to 2.
It is particularly effective to add 0% by weight, preferably 0.01 to 1.0% by weight.

If the amount is less than this, the effect will be poor, and if more than this is added, the cost will only increase and no improvement in the effect will be seen.

A typical example of the aromatic saturated thermoplastic polyester resin used in the present invention is polybutylene terephthalate (PBT). It is obtained by polycondensation of terephthalic acid and butylene glycol (also known as 1,4-butanediol), and is widely available on the market.

The polybutylene terephthalate used in the present invention includes not only simple polymers but also those blended with various modifiers. An example of this modifier is an impact modifier, and it is known that a modified polyolefin in which an unsaturated carboxylic acid is grafted onto an ethylene or ethylene-propylene copolymer is used.

The thermoplastic saturated copolyester resin used in the present invention is
20 to 50 mol%, preferably 30 to 40 mol% of a chain dibasic acid component, such as azelaic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid, etc., is copolymerized with ethylene glycol, based on the starting material terephthalic acid. Furthermore, chain polyhydric alcohols having different molecular weights may also be used together as a glycol component.

The thermoplastic saturated copolyester resin is used in an amount of 0.1 to 10% by weight, preferably 0.1 to 10% by weight, based on polybutylene terephthalate.
Add 5 to 2% by weight. If the amount is less than this, the effect will be small (and if it is more than this, the rigidity and heat resistance of the composition will decrease, which is not preferable).

This effect is extremely remarkable as follows and makes the present invention very useful.

First, when a blend of this composition is mixed at high speed with a high-speed mixer such as a Henschel mixer, the copolyester in the blend has a softening point or melting point of 100 to 165°C, so it easily melts or softens due to frictional heat generation and becomes metal. When the powder and polybutylene terephthalate powder are adhered and cooled with subsequent mixing at low speed, a granular mixture of metal powder and resin powder is formed.

By creating a granular mixture in this way, during storage,
Alternatively, molded products with uniform composition can be produced without separation during transportation.

The next effect of the copolyester is that it quickly melts or softens in the molding machine cylinder and wets the wall surface, thereby reducing the effect of cylinder wear caused by metal particles.

Additionally, the copolyester reduces the viscosity of the melt composition,
As a result, the polybutylene terephthalate generates heat due to the shearing action of the screw, which causes molecular scission and eliminates the cause of lowering the mechanical strength of the molded product. This effect is particularly noticeable in highly concentrated filling compositions, which are the object of the present invention.

Other effects of the copolyester are that it imparts appropriate flexibility to the molded product, improves mold release during molding processing, and improves the strength of the molded product.

In the prior art, there is a method of adhering metal powder and resin with a binder, but the function and effect of the copolyester in the present invention is not simply as a binder for the mixture, but as described above, the function and effect of the copolyester are based on the molding process and the properties of the composition. It plays an extremely important role. The composition according to the present invention may be added with an antioxidant, for example, a phenolic antioxidant such as tetraester type hindered phenol, or tetrakis (2,4-di-t-butylphenol)-4゜4'- by a conventional method. Phosphorous antioxidants such as biphenylene phosphite, etc., in an amount of 0.01 to 5 M%, preferably 0°1 to 2
It is possible to prevent thermal deterioration during molding and actual use by adding % by weight.

Furthermore, in order to prevent deterioration of polybutylene terephthalate due to metal powder, a heavy metal deactivator can be added.

Examples of heavy metal deactivators include 3(N-salicyloyl)amino1.2.4) lyazole, or N,N''-
Bis(3-(3,5-di-t-butyl-4-hydroxylphenyl)propionyl)hydrazine to the resin,
By blending 0.01 to 5%, preferably 0.1 to 2%, a significant stabilizing effect can be obtained.

In addition, a lubricant or a mold release agent may be added to this composition in order to control material deterioration due to excessive shear heat generation during the plasticization and kneading process and to improve the releasability of the molded product from the mold. I can do it.

For this purpose, 0.01 to 2% by weight of a lubricant such as stearic acid, methylene bisstearamide, montan acid wax, or low molecular weight polyethylene may be added to the composition.
, preferably 0.05 to 0.5% by weight.

In addition, depending on the required performance of the product made from the composition, lubricants and antifriction agents such as silicone oil, graphite, molybdenum disulfide, and polytetrafluoroethylene powder may be added to the composition.
．． It is also possible to mix 1 to 20% by weight, preferably 2 to 10% by weight.

The composition according to the present invention is melt-kneaded using an axle-shaft extruder, a twin-screw extruder, an extruder equipped with a kneading mechanism, etc. in a conventional manner to form pellets, and then formed into pellets using an injection molding machine in a conventional manner. Can be molded.

As another method for producing the composition according to the present invention, the present composition is mixed at high speed with a high-speed mixer such as a Henschel mixer, and the copolyester in the blend is melted by frictional heat generation, and the copolyester is mixed with metal powder etc. A mixture in which polybutylene terephthalate powder is uniformly mixed and adhered is prepared, and this is melted and mixed in an injection molding machine and injection molded to produce a plastic molded product filled with a high concentration of metal powder or metal oxide. It's a method.

In carrying out this method, an ordinary screw in-line type injection molding machine can be used, but a structure in which the screw has a dispersion function, such as a bottle type or a gear set structure, can also give better effects.

Furthermore, the mechanism described in Japanese Patent No. 1104727 can also provide extremely good results.

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 into the cylinder of the molding machine in a starvation state. It is preferable to mold the two pieces one by one.

This effect is due to the fact that the material is sufficiently aerated and the high viscosity material during the melting process does not hinder the forward movement of the screw during injection, so the screw moves within the set stroke. This is because it is extremely effective in manufacturing precision molded products by smoothly advancing according to the combination of position and injection speed.

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

te1 action The present invention provides a thermoplastic polyester resin composition containing a high concentration of metal powder or metal oxide powder. By using the No. 10 mixed resin as a matrix, a composition with excellent molding processability, molding stability, and strength of molded products is provided.

Furthermore, the present invention has also developed a method for producing molded articles of the composition with high dimensional accuracy.

(f) Examples The structure of the present invention will be specifically explained with reference to Examples below.

Example 1 (1) Iron powder with an average particle size of 200 mesh made by the atomization method (KIP300A manufactured by Kawasaki Steel, specific gravity 7.85)
) While mixing 5,000 g at low speed in a high-speed mixer (Super Mixer manufactured by Kakuda Seisakusho Co., Ltd.), add zircoaluminate coupling agent (CAV
A mixed solution of 25 g of COMOD F) and 125 g of denatured alcohol was added, followed by continued mixing at 750 r/a+ for 30 minutes, and the temperature was raised to 100° C. to bring out the alcohol content to obtain treated iron powder.

(2) Continue with powdered polybutylene terephthalate resin (
DURANEX 2002 manufactured by Polyplastics (pulverized product) 880 g, hindered phenol type antioxidant (AO-60 manufactured by Adeka Argus) 5 g, heavy metal deactivator (mark ODA-1 manufactured by Adeka Argus)
) and 15 g of a saturated copolyester resin (Vylon 103 manufactured by Toyobo Co., Ltd.) were added and mixed at 750 r/m for 30 minutes. The temperature of the mixture rose to 150° C. and the copolyester resin melted.

(3) Continue cooling the mixer jacket with water for 10 minutes.
Mixing was continued for 20 minutes at 0 r/m to obtain a granular mixture in which iron powder and PBT powder were fused.

(4) This mixture is transferred to an injection molding machine equipped with a melt kneading mechanism described in Japanese Patent No. 1104727, from a screw feeder interlocking with a screw to a supply section in the molding machine cylinder. The mixture was supplied so as to obtain the desired condition, and molding was performed.

Comparative Example 1 Using the same formulation and procedure as Example 1, using 895% polybutylene terephthalate resin without using saturated copolyester.
The mixture was then molded in the same manner.

However, the mixture separated in the cylinder of the molding machine, and iron powder clogged the screw, preventing it from rotating (making molding impossible).

Comparative Example 2 A mixture was prepared using the same formulation and procedure as in Example 1, but using 30 g of a polyurethane resin binder (Merci 525, manufactured by Toyo Polymer Co., Ltd.) without using the saturated copolyester, and molded in the same manner.

Comparative Example 3 Polyvinyl acetate emulsion (Vinizol 602 manufactured by Daido Kasei Kogyo Co., Ltd.) with a solid content of 50% without using saturated copolyester using the same formulation and formulation procedure as in Example 1.
A mixture was made using g and molded in the same manner.

The injection molding conditions for Example 11, Comparative Example 2.3 were as shown in Table 1.

The test specimens are ASTM D6384 type tensile test specimens (total length 165 m, wall thickness 3.2 fins) and ASTM D790 bending test specimens (total length 127 m + 11 m, width 12.7 mm, thickness 6.4 mm).

Table 1 Molding Conditions The tensile strength, flexural modulus, eye shift impact strength, and specific gravity of the obtained molded product are as shown in Table 2.

Table 2 Comparative Example 4 of Physical Property Measurement Results (1) Iron powder with an average particle size of 200 mesh produced by the atomization method (K I P2O3A manufactured by Kawasaki Steel, specific gravity 7.
85) Using a high-speed mixer (Super Mixer manufactured by Kawasaki Tetsu Co., Ltd.), 4,700 g of silane coupling agent was added to 25 g of silane coupling agent (
Shin-Etsu Chemical Co., Ltd. K B M2O3 was diluted 10 times with a 9/1 solution of denatured ethyl alcohol/water) and 30
Mixing was continued at 150 r/m for 1 minute to volatilize the alcohol content to obtain treated iron powder.

(2) Continuing powdered nylon 6 resin (Ube Industries, Ltd. Chi JI)
O11F) 675g5Q, P-) luenesulfonamide mixture (68g of Tofpsiza 5' manufactured by Fuji Amido Chemical Co., Ltd., 25 g of methylene bisamide (Panloop NI8P manufactured by Taneyaya Kasei Co., Ltd.), 1 of soluble 8-nylon
500 g of a 5% alcohol solution (EMI5, manufactured by Chizuichi Co., Ltd.) was added and mixed at 500 r/m for 5 minutes. This mixture was dried in 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 Comparative Example 2 was
Injection molding was performed using an injection molding machine equipped with a kneading mechanism described in No. 104727, and by supplying the material from a screw feeder interlocking with the screw of the injection molding machine so that the cylinder feed section of the molding machine was kept in a starved state.

(4) Physical property test ASTM D638 type 4 tensile test piece (
wall thickness 3.2n) and ASTM 0790 bending test piece (total length 12.7m, width 12.7m, thickness 3.2mm)
A mold was attached to form a test piece.

The molding conditions are shown in Table 3.

After the material of Example 1 was jointed at 23°C and 50%RH,
The material of Comparative Example 4 was in an absolutely dry state immediately after molding and at 23°C 50%
Measurements were performed after adjusting the RH condition.

The results are shown in Table 4.

Table 3 Molding conditions Table 4 Physical property measurement results 1g) Effects of the invention This invention is a resin composition that is filled with a high concentration of money powder, etc. Plastic copolyester resin (e.g. 20-50% for terephthalic acid)
It is composed of a resin copolycondensed with mol% of a chain dibasic acid, and forms a granular mixture with metal powder, etc., and does not separate during storage or transportation, and is It prevents cylinder wear, prevents a decrease in mechanical strength due to thermal deterioration, gives the molded product appropriate flexibility, improves mold release during molding, and is useful for improving the precision and strength of the product. be.

Furthermore, an efficient method for producing the composition of the present invention has been completed.

Claims (10)

[Claims] (1) Surface-treated metal powder or metal oxide powder 8
0-92% by weight, 99.9/0.1-9 of aromatic saturated thermoplastic polyester resin and thermoplastic copolyester resin
A highly concentrated metal powder filled plastic composition consisting of 8-20% by weight of a 0/10% by weight mixture. (2) The composition according to claim 1, wherein the metal powder is iron powder, copper powder, brass powder, or zinc 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 thermoplastic polyester is polybutylene terephthalate. (5) The composition according to claim 1, wherein the thermoplastic copolyester resin is a copolyester obtained by copolycondensing 20 to 50 mol% of a chain dibasic acid component. (6) The composition according to claim 1, wherein the metal powder or metal oxide powder is surface-treated with a silane coupling agent. (7) The composition according to claim 1, wherein the metal powder or metal oxide powder is surface-treated with a zircoaluminate coupling agent. (8) A method for producing a plastic composition filled with a high concentration of metal powder, etc., which comprises molding the powder mixture using a screw in-line injection molding machine when producing the composition according to claim 1. (9) The method for producing a composition according to claim 8, wherein the injection molding machine is a molding machine equipped with a kneading mechanism described in Japanese Patent No. 1104727. (10) The mixed material according to claim 8 is characterized in that the mixed material is supplied from a material supply device that operates in conjunction with the screw of the injection molding machine so that the feed section of the molding machine cylinder is starved. Method for producing the composition.