JPS58127761A - High specific gravity composite material reinforced with organic fiber - Google Patents

Abstract

PURPOSE:To obtain the titled composite material with a high specific gravity providing a molding with smooth appearance, low coefficient of thermal expansion, high mechanical strength, by blending with a thermoplastic resin an inorg. filler having a high specific gravity and an aromatic polyamide fiber each in a specific wt. ratio. CONSTITUTION:150-500pts.wt. powder selected from a group of inorg. filler consisting of a finely divided metal with a specific gravity of 3 or more (e.g., copper powder, tin powder) and/or metal oxide, hydroxide, carbonate, sulfate, silicate, double salt thereof, sulfide, etc., 1-50pts.wt. strand chop or pulp of arom. polyamide fiber cut into 1/4 inch or less, and, if necessary, 1-50pts.wt. reinforcing fiber such as glass fiber, carbon fiber, or a variety of whiskers are blended with 100pts.wt. thermoplastic resin such as polyamide, polyethylene, etc. to yield the intended composite material with a high specific gravity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a high specific gravity composite material suitable for injection molding reinforced with aromatic polyamide fibers, which has a smooth appearance,
The present invention relates to a high specific gravity composite material that can provide molded products having a low coefficient of thermal expansion and high mechanical strength.

Hitherto, high-density composite materials made by densely filling thermoplastic resin with metal powder, etc., have been known. There is a limit to the specific gravity, at most about 2.51
could only be constructed using composite materials. The problem is that even inorganic reinforcing fibers with high elasticity, which are highly effective in low-filler composites, are mostly crushed during kneading and molding in high-filler filler composites, resulting in a significant reduction in the reinforcing effect. was there.

My father, thermoplastic resin, has created a variety of useful products in the fields of industrial parts, low-light electrical parts, transportation equipment, etc., as an alternative to metals, ceramics, wood, etc., by taking advantage of its excellent characteristics such as lightness and high moldability. However, in addition to its high coefficient of thermal expansion, its characteristic lightness and electrical insulation properties often become disadvantages, limiting its use. Therefore, for applications that require vibration damping properties, applications that do not want dimensional changes due to thermal atmosphere, applications that require antistatic properties, sound insulation properties, electromagnetic wave shielding properties, and reflection properties, the specific gravity is large and the mechanical strength is low. There are high expectations for composite materials with excellent productivity. In addition, composites made by simply compounding thermoplastic resin with metal powder and/or metal oxides, etc., or by adding inorganic fibers such as glass fiber to these, have particularly excellent impact resistance strength among the desired physical properties. In addition, aromatic polyamide fibers such as DuPont's Kepler (registered trademark) are well known as reinforcing materials for reinforced plastics, and high-strength reinforced plastics composited with carbon fibers are used in aviation. Space industry.

Its reputation in the field of land and sea transportation equipment is increasing. The aromatic polyamide fibers used in these applications are either roving yarn or cloth.

It is a matte, which is composited with a thermosetting resin such as an uncelled polyester resin or an epoxy resin, and molded and cured by heating and pressing using a filament Windinge method, a pultrusion method, a sheet moldingen pounding method, or the like. However, initially, it was difficult to cut aromatic polyamide fibers into short fibers due to their high elasticity and high tensile strength, which was a factor that prevented their application to thermoplastic reinforced plastics. In recent years, special machines for cutting have been developed, and we have finally begun to see the production of strand-like chops or pulp-like short fibers with a certain cut length, and its use is expanding as an alternative to asbestos and glass wool, such as insulation materials. However, because of its poor unbundling properties, it is difficult to uniformly disperse it in resins, so there have been few examples of its application to thermoplastic reinforced plastics.

The present invention aims to overcome the above-mentioned drawbacks and provide an injection moldable high specific gravity composite material reinforced with aromatic polyamide fibers. In other words, metals and/or their oxides and various salts have the effect of imparting functions such as high specific gravity, thermal expansion suppression, and antistatic properties, and they also have the effect of imparting functions such as high specific gravity, thermal expansion suppression, and antistatic properties. It was discovered that it is a good unbundling material, and the present invention was completed. The high specific gravity composite material according to the present invention contains metal powder and/or metal oxides, hydroxides, carbonates, sulfates, silicates, double salts thereof, with a specific gravity of 3 or more, based on 100 parts by weight of the thermoplastic resin. A total of 150 to 500 parts by weight of powder of one or more types of inorganic fillers consisting of sulfides, etc., and 1 to 50 parts by weight of aromatic polyamide fiber alone or glass fiber, carbon fiber, various whiskers, etc. It is made by dispersing and blending 1 to 50 parts by weight of at least one kind of reinforcing fibers, and has a specific gravity of 2.5 or more suitable for injection molding. Products injection molded using this material have excellent mechanical strength, and have secondary improvements such as a reduction in molding shrinkage and a reduction in the coefficient of thermal expansion due to not only high specific gravity but also high filling. Therefore, the application can be extended from applications requiring only weight as a function, such as stationery decorations, to the field of engineering plastics.

The thermoplastic resin in the present invention includes polyamide, polyethylene, polypropylene, olefin-modified vinyl alcohol (for example, GL resin from Nippon Gosei Kagaku Co., Ltd.),
Crystalline resins such as polyphenylene sulfide, polystyrene and its copolymers, ethylene vinegar picopolymers, and polysulfones.

It includes non-grade resins such as polyether sulfone and thermoplastic elastomers typified by polyurethane. or,
Fillers for obtaining a high specific gravity include metals with a specific gravity of 3 or more, such as copper, tin, zinc, iron, and lead.

Typical examples include metals such as tungsten and titanium, but of course noble metals such as silver and gold may also be included. The metal oxide does not necessarily have to have a specific gravity of 3 or more, and any metal oxide can be used as long as it can be expected to have a thermal expansion suppressing effect, such as copper oxide and zinc oxide.

Iron oxide, aluminum oxide, tin oxide, lead oxide.

In addition to high specific gravity oxides such as titanium oxide and antimony oxide, silicon dioxide and the like with a specific gravity of 3 or less are also included.

Other than metal oxides that can be expected to have similar effects are metal hydroxides, carbonates, and sulfates.

Typical examples include silicates, double salts thereof, sulfides, etc., such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, calcium carbonate, magnesium carbonate, barium sulfate, calcium metasilicate, and mica. Note that the filler is not limited to the examples described above, and may be surface-treated with a coupling agent. Further, as the reinforcing material, short fibers of aromatic polyamide fibers or pulp are used as an impact resistance imparting component. Examples of these include DuPont's Kevlar (registered trademark), Akzo's Allen force (registered trademark), Ryotai Co., Ltd.'s Cornets (registered trademark)! DuPont's Nomex (registered trademark), etc. From the viewpoint of imparting toughness, the grade is preferably a low modulus type, such as Kevlar 29, but is not limited to this.On the other hand, various known materials can be used as the reinforcing material to be combined as a stiffening component. This includes, for example, glass fibers and carbon fibers.

Examples include various whiskers containing potassium titanate fibers, high modulus aromatic polyamide fibers, and the like. Of course, these reinforcing materials include those treated with a surface treatment agent such as a silane coupling agent.

In addition to the above-mentioned various composite materials, various known additives necessary for mixing or injection molding, such as lubricants, surface treatment agents, and plasticizers, may be used as appropriate, and if necessary, they may be added with functions specific to the molded product. For example, various lubricity imparting agents to impart wear resistance and wear tank resistance, and antistatic agents to further improve antistatic properties may also be added.

EXAMPLES The high specific gravity composite material according to the present invention will be specifically explained below with reference to Examples.

[Example 1] 100 parts by weight of polyamide (Nylon 61, Amiran 1001°' manufactured by Toshi Co., Ltd.), 300 parts by weight of metal zinc powder, 50 parts by weight of zinc oxide powder, and 1 part by weight of calcium stearate were heated to 240°C. Pour into the pressurized Ni-Goo and continue mixing at normal pressure. Kevlar 29-970 (178 inch cut) when the internal temperature exceeds approximately 150°C
Add 30 parts by weight and start pressure mixing. Internal temperature 220'
As the polyamide begins to melt near C, the load on the kneader reaches its maximum, and as the melting and trajectory are completed, the load on the kneader decreases and becomes stable. At this point, the kneading was completed, and visual observation of the contents revealed that the Kevlar was well unbundled and the dispersion was good. The contents were taken out, passed through a roll, flattened, cooled and pulverized to obtain a molding material. After drying this molding material at 90°C, the maximum mold clamping pressure was 100°C.
Mechanical strength test pieces were molded in accordance with JIS standards using an injection molding machine with a cylinder temperature of 240°C and a mold wetness of 80"C.Molding was carried out smoothly, and the molded product was smooth. It had a glossy finish, high mechanical strength, and excellent impact resistance.The specific gravity of the obtained molded product was 2.89.

[Example 2] 100 parts by weight of polyamide (Amilan 1001).

300 parts by weight of metal zinc powder, 50 parts by weight of zinc oxide powder,
A single portion of calcium stearate was placed in a pressurized Ni-Goo heated to 240°C, and mixing was continued at normal pressure.

When the internal temperature exceeds approximately 150°C, Kevlar 29-
Add 20 parts by weight of 970 and start mixing under pressure. The kneader load reaches its maximum as the polyamide begins to melt at an internal temperature of around 220°C, and as the kneading is completed, the kneader load decreases and stabilizes. After confirming the dispersion of Kevlar in the same manner as in Example 1, 50 parts by weight of 1/8 inch chopped strand glass (aminosilane treatment) was added.
Kneading was continued for a minute until completion, and the contents were passed through a roll, cooled, and ground to form a molding material. This molding material was injection molded under the same conditions as Example 1, and the binding, moldability, appearance, and mechanical strength were good.

A molded part with an extremely excellent coefficient of thermal expansion was obtained. Note that the specific gravity of the obtained molded product was 2.91.

[Example 3] All the formulations were the same as in Example 2, except that Kevlar was changed to Kevlar 29-p (pulp type) and 20 heavy machinery parts.

As a result of mixing and kneading under the same conditions, a molding material with extremely good dispersion of P) was obtained. This molding material was used in Example 1.
As a result of injection molding under the same conditions as in Example 2, a molded product with excellent moldability, appearance, mechanical strength, and coefficient of thermal expansion was obtained. Note that the specific gravity of the obtained molded product was 2.96.

[Comparative example 1] Polyamide (Amilan 1001) 100 parts by weight.

300 parts by weight of gold lead powder, 50 parts by weight of acid [L, zinc powder, and 1 part by weight of potassium stearate were charged into a pressurized Ni-Goo heated to 240°C, and mixed and kneaded under pressure. As soon as the melting and kneading of the contents is completed, the load on the Ni-Goo decreases and becomes stable. At this point, the crosslinking was completed, and thereafter, the mixture was cooled and pulverized to obtain a molding material in the same manner as in the above example. After drying this molding material at 90°C, the cylinder humidity was 230°C and the mold humidity was 80'C using the same molding machine as in the above example. A mechanical strength test piece was molded in accordance with JIS standards under the following conditions. Although molding was extremely easy and it was possible to obtain a molded product with an excellent appearance, it had low mechanical strength, especially impact resistance, and a high coefficient of thermal expansion, making it extremely impractical. .

The specific gravity of the obtained molded product was 3,818.

[Comparative Example 2] The same formulation as Comparative Example 1 was mixed and kneaded under the same conditions, and after confirming that the contents were completely melted and mixed, 1/8 inch chopped wood treated with an aminosilane coupling agent was prepared. After adding 70 parts by weight of strand glass and kneading for 3 minutes, the mixture was cooled and crushed in the same manner as in the above example to obtain a molding material. As a result of molding this molding material under the same conditions as in Example 1, it had good moldability and a smooth appearance.
A molded product having a low coefficient of thermal expansion and high rigidity was obtained, but the impact resistance was poor and the product was poor in practical use. still,
The specific gravity of the obtained molded article was 3.07.

[Comparative Example 3] The same formulation as in Example 1 was used, but 30 parts by weight of Kevlar 29-970 was added after the contents were completely mixed and mixed, and the mixing was continued for 20 minutes, but the Kevlar strand-like The unbundling and dispersion of the chop was bad, so 1 more
After kneading was continued for 0 minutes, the kneading was terminated, and the mixture was cooled and pulverized to obtain a molding material in the same manner as in the above example. Concentrations of Kevlar were exposed in some places in the molding material obtained, indicating poor unbundling and dispersion. As a result of molding this molding material under the same conditions as in Example 1, the resulting molded product exhibited various defects believed to be due to poor dispersion of Kevlar. For example, the surface of the Kevlar block was exposed, resulting in poor appearance and large variations in mechanical strength, resulting in poor reliability.

[Example 4] GL resin (olefin-modified vinyl alcohol resin manufactured by Nippon Gosei Kagaku Co., Ltd.) 100 parts of TE, rJL, 300 parts of metal lead powder, 50 parts by weight of titanium oxide powder, 1 part by weight of canonium stearate, 220 parts by weight Pour into a pressurized Ni-Goo heated to °C and mix under normal pressure. When the internal temperature exceeds approximately 120°C, 20 parts by weight of Kevlar 29-970 is added and mixing under pressure is started. When the internal temperature is around 180°C, the melting of the GL resin begins, and then the load on the kneader reaches its maximum, and as the crosstalk is completed, the load on the kneader decreases and becomes stable. Next, after checking the dispersion of Kevlar, 1
50 parts by weight of 71.6-inch carbon fiber (Tareki Chop manufactured by Kureha Fhigaku Co., Ltd.) was added and mixed under pressure for 3 minutes to complete the process, and then cooled and pulverized in the same manner as in Example 1. It was made into a molded ion material. As a result of molding the obtained molding material under the same conditions as in Example 1 and Sub-Example 1, a high specific gravity molded product having excellent various physical properties as in Example 2 was obtained. Among them, it is noteworthy that it has high elasticity and excellent durability and loanability.

Note that the specific gravity of the obtained molded product was 3.01.

[Comparative Example 4] A molding material was crushed using the formulation of Example 4 except that Kevlar was removed, and injection molding was performed using the same material as Example 4. Although the obtained molded product had a smooth appearance, a low coefficient of thermal expansion, and high rigidity, it had poor impact resistance and did not have practicality commensurate with cost. The specific gravity of the obtained molded product is 3.1.
It was 9.

[Example 5] 100 parts of polypropylene resin (Showa Aroma MA410'' manufactured by Showa Denko Co., Ltd.), 400 parts by weight of metal tungsten powder, 50 parts by weight of zinc oxide powder, and 941 parts by weight of stearic acid calcium were heated to 200°C. Pour into a heated pressurized Ni-Goo and continue mixing under normal pressure. Internal temperature is 80°C.
When the temperature exceeds 20 parts by weight, 20 parts by weight of Kevlar 29-p is added and mixing under pressure is started. Melting begins at an internal temperature of around 160°C, after which the load on the kneader reaches its maximum, and as kneading is completed, the load on the kneader decreases and becomes stable. Subsequently, after confirming the dispersion of Kevlar, 50 parts by weight of potassium titanate fiber (manufactured by Otsuka Chemical Co., Ltd., treated with an aminosilane coupling agent) was added and mixed under pressure for 5 minutes. A molding material was obtained in the same manner as in the example described above. The obtained molding material was heated to a cylinder humidity of 200°C.
When injection molding was performed at a mold humidity of 60°C, the fluidity was very good. The molded product showed extremely excellent smoothness, a low coefficient of thermal expansion, and excellent mechanical strength.

Note that the specific gravity of the obtained molded product was 3.77.

[Comparative Example 5] A molding material was produced and molded in the same manner as in Example 5 except that Kevlar was removed from the formulation of Example 5 and the potassium titanate fiber was changed to 70 parts by weight. The obtained molded product had a smooth appearance and a low coefficient of thermal expansion, but had the drawback of poor impact resistance. The specific gravity of the obtained molded product is 3.99.
Met.

[Example 6] 100 parts by weight of A, BS resin (Sevian-610'' manufactured by Daicel Corporation), 300 parts by weight of copper metal powder, 50 parts by weight of copper oxide powder, 1 part by weight of stearic acid was put into a pressurized Ni-Goo heated to 240°C, and then Kevlar 29-4 was added in the same manner as in Example 1.
A molding material was produced by adding 30 parts by weight of 70. As a result of injection molding at a cylinder temperature of 24.0'C and a mold temperature of 80'C, the molded product had a low coefficient of thermal expansion, excellent balance of mechanical properties, and a surface resistivity of 8.9X10°.
It exhibited an extremely excellent conductivity of ΩQm (~fCo).The specific gravity of the obtained molded product was 3.05.

[Example 7] 100 parts by weight of polyphenylenenonalphide (manufactured by Philips Co., Ltd. "Rydon")-4°'), 300 parts by weight of iron powder,
300 parts by weight of iron powder, 50 parts by weight of zinc oxide powder, and 1 part by weight of magnesium stearate at 30°C.

The mixture was placed in a pressurized plastic kneader heated to C, and mixing at normal pressure was continued. When the internal temperature exceeds approximately 230'C, Kevlar 2
Start mixing 20 parts by weight of 9-470 under zero pressure.

As the polyphenylene sulfide melts smoothly from around the internal temperature of 29 o'a, the load on the kneader reaches its maximum, and then the load on the kneader rapidly decreases and becomes stable. At this point, the contents were completely kneaded and Kevlar was observed to be well dispersed. Next, glass fiber (1/16
Add 50 parts by weight of inch chopped strands,
After continuing to pressurize and mix for 1 minute, the mixture was cooled and pulverized to obtain a molding material in the same manner as in the above-mentioned example.

Apply this molding material to the cylinder temperature: 340°C2 mold humidity: 1
As a result of injection molding at 40°C, a molded product was obtained which had good moldability and was extremely excellent in appearance, mechanical strength, thermal expansion coefficient, etc. The specific gravity of the obtained molded product is 3.2.
It was 8.

Next, the above Examples 1 to 7. The various physical properties of the molded products obtained in Ratio Examples 1 to 5 are shown in the table below.

As mentioned above, the high specific gravity composite material according to the present invention has the important advantage that it has good moldability and can provide a molded article having a smooth appearance, a low coefficient of thermal expansion, and high mechanical strength. There is.

Agent Yasushi Shinohara Procedural amendment (voluntary) November 12, 1980 Commissioner of the Japan Patent Office Tono 1, Indication of the case Patent application No. 1983-9012 Publication No. λ Name of the invention High specific gravity reinforced with organic fibers Composite material 3, person making the amendment Patent applicant: 2-30-1 Namiki, Yoguchi-shi, Saitama Address: 19°, Shinbashi-5, Minato-ku, Tokyo 105 Phone: Tokyo (432) 4 5 7 6 (6582) Patent attorney Yasushi Shinohara 5 , Detailed description of the invention in the specification to be amended.

6. Contents of the amendment (1) "Aromatic polyamide short fibers" on page 5, lines 6-7 of the specification letter is corrected to "aromatic polyamide short fibers."

(2) On page 5, line 18 of the specification, "materials with a specific gravity of 2.5 or more" is corrected to "high specific gravity composite material."

C3) Change “appropriately” to “appropriately” on page 8, line 11 of the letter of specification.
I am corrected.

(4) "Molded part" on page 10, line 18 of the specification letter is corrected to "molded product."

(5) “Bending elastic modulus (Kq/d
)" should be corrected to "bending elastic modulus CK9/mm".

Claims (4)

[Claims] (1) Metal powder and/or metal oxide or hydroxide having a specific gravity of 3 or more based on 100 parts by weight of the thermoplastic resin. A total of 150 to 500 parts by weight of powder of one or more types of inorganic fillers consisting of carbonates, sulfates, silicates, double salts thereof, sulfides, etc., and 1 to 500 parts by weight of aromatic polyamide fibers. 50 parts by weight alone or with glass fiber, carbon fiber,
A high-density composite material made by dispersing and blending various types of whiskers, etc., in combination with 1 to 50 parts by weight of at least one type of fiber. (2) The high specific gravity composite material according to claim (1), wherein the aromatic polyamide fiber is a chopped strand cut into 1/4 inch or less. (3) The high specific gravity composite material according to claim (1), wherein the aromatic polyamide fiber is pulp. (4) The high specific gravity composite material according to claim (1), wherein the aromatic polyamide fiber and the reinforcing fiber are treated with a silane thread coupling agent in advance.