JP2000256505A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition containing wollastonite, having increased reinforcing property, improved to obtain a product having high whiteness and having expanded application field. SOLUTION: The objective resin composition contains 5-70 wt.% wollastonite fiber composed mainly of wollastonite, containing <=0.5 wt.% Fe2O3 and <=0.49 wt.% Al2O3 and having an average fiber length of 20-50 μm, an average fiber diameter of 0.5-5 μm and an average aspect ratio of 7-100 and 95-30 wt.% thermoplastic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition, and more particularly to a resin composition containing wollastonite having a specific component and shape, and having high rigidity, high heat resistance, excellent surface smoothness, and good colorability. The present invention relates to a thermoplastic resin composition from which a molded article having a beautiful appearance can be obtained.

[0002]

2. Description of the Related Art Conventionally, there has been known a technique for improving physical properties such as mechanical strength and heat resistance by filling a thermoplastic resin with various inorganic fillers such as tantalum, talc, mica and glass fiber. Thermoplastic resins filled with these inorganic fillers are used for various applications mainly in the industrial parts field of automobile parts, electric and electronic parts, and have a high mechanical strength, especially rigidity, impact resistance and elongation. The demand for improving the so-called toughness balance is extremely high. Furthermore, recently, there has been a demand for a molding material having improved rigidity and heat resistance in accordance with the high quality trend of various products.
The role played by the fibrous filler plays an extremely important role in meeting these needs.

[0003] Examples of the fibrous reinforcing filler include glass fibers, carbon fibers, alumina fibers, boron fibers, potassium titanate whiskers, basic magnesium sulfate whiskers, and aluminum borate whiskers. However, these fibrous or needle-like fillers are all expensive, and have the drawback that they have poor surface smoothness, are difficult to color, or have an insufficient reinforcing effect, and their application fields are limited. .

[0004]

It is also known to use wollastonite as a reinforcing filler.
Conventional wollastonite has low fibrous properties, large size and low reinforcing properties, except for use for reducing water absorption and shrinkage of polyamide, it is simply a use as a bulking agent for cost reduction, The range of application was limited. An object of the present invention is to enhance the reinforcing performance of a resin composition using wollastonite, improve the resin composition so as to obtain a product having high whiteness, and expand its application range.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises wollastonite as a main component and Fe ₂ O ₃ : 0.5% by weight or less and Al ₂ O ₃ :
A resin composition comprising a wollastonite fiber containing 0.49% by weight or less and a thermoplastic resin.

[0006] The present inventors have studied the correlation between the reinforcing performance of inexpensive wollastonite and the fiber shape, fiber size and fiber composition. As a result, the reinforcing performance has high fibrous properties of wollastonite and a small size. It has been found that a uniform composition is effective, and that the composition is higher in whiteness as the purity of CaO and SiO ₂ as components of wollastonite is higher.

According to the present invention, wollastonite has an average fiber length of 20 to 50 μm, an average fiber diameter of 0.5 to 5 μm, an average aspect ratio of 4 to 50, and Fe ₂ O as an impurity.
₃ at 0.5% by weight or less and Al ₂ O ₃ at 0.49% by weight
The present invention relates to a resin composition containing the following wollastonite fibers and a thermoplastic resin.

The thermoplastic resin used in the present invention includes, for example, crystalline resins such as polypropylene, polyethylene, polyamide, thermoplastic polyester, polyphenylene sulfide, polyether ether ketone, polystyrene, acrylonitrile-butadiene-styrene, polyvinyl chloride, and polycarbonate. And amorphous resins such as polyphenylene ether, polyethersulfone, and polyetherimide. These resins may be used as a polymer alloy combining two or more resins.

Further, a thermoplastic elastomer can be added as an additive to improve the impact value of the wollastonite-filled composite material. Examples of the thermoplastic elastomer include polystyrene, polyolefin, polyvinyl chloride, polyurethane, and polyamide elastomers. The wollastonite fiber used in the present invention contains CaSiO ₃ as a main component, and can be used by pulverizing and classifying naturally occurring fiber.

There are two types of wollastonite, α-type and β-type. Α-type has many grains and a low aspect ratio, and has a melting point of 1125 ° C. The β type is fibrous, has a high aspect ratio, a melting point of 1,545 ° C., and has excellent reinforcing performance.
In the present invention, among these wollastonites, Fe ₂ O ₃ as a trace component is 0.5% by weight or less and Al ₂ O ₃
Containing 0.49% by weight or less. Such wollastonite is excellent in reinforcement performance, particularly excellent in whiteness, and has stable quality. When the content of Fe ₂ O ₃ exceeds 0.5% by weight or the content of Al ₂ O ₃ exceeds 0.49% by weight, the granularity increases, the reinforcing effect is poor, and particularly, the decrease in whiteness and the variation in quality are large. Fe ₂ O ₃ : 0.5% by weight or less, Al ₂ O
₃ : Limited to 0.49% by weight or less. Such wollastonite is produced in the United States, Canada, India, Finland and the like, and can be obtained.

[0011] The wollastonite used in the present invention has an average fiber length of 20 to 50 µm and an average fiber diameter of 0.
Those having a thickness of 5 to 5 μm and an average aspect ratio of 7 or more are preferred. Particularly preferred wollastonite is 0.5% by weight or less of Fe ₂ O ₃ and 0.1% of Al ₂ O ₃ as trace components.
It contains not more than 49% by weight, has an average fiber length of 30 μm and an average fiber diameter of 3.5 μm.
The applicant has refined in Japan.

The wollastonite used in the present invention is:
Even without surface treatment, the effect of compounding in the resin is recognized, but a normal coupling agent, for example, epoxy silane,
When surface treatment is performed with a silane coupling agent such as aminosilane or acrylic silane or a titanate coupling agent, mechanical properties are further improved. In particular, epoxysilane and aminosilane are particularly effective among them.

In the wollastonite fiber used in the present invention, as a sub-component, as long as the object of the present invention is not impaired,
Known fibrous materials may be mixed. Examples of such fibrous materials include potassium titanate whiskers, glass fibers, carbon fibers, aramid fibers, vinylon fibers,
Needle-like tankar, gypsum fiber, sepiolite, zonotolite, silicon carbide, silicon nitride, phosphate fiber, dawsonite and the like.

In the resin composition of the present invention, the mixing ratio of wollastonite fibers (including the above-mentioned subcomponents) must be 5 to 70% by weight, and the resin must be 95 to 30% by weight.
When the blending ratio of the wollastonite fiber is less than 5% by weight, the blended fiber functions as a foreign substance, and the improvement of the mechanical properties and the heat deformation resistance of the molded product is not satisfactory. On the other hand, when the compounding ratio of the fibrous material exceeds 70% by weight,
Melt kneading to the resin is not smooth, and the fluidity at the time of molding is poor, so that molding becomes extremely difficult, and a problem that a good surface appearance cannot be obtained is likely to occur, which is not preferable. The most preferable amount of the wollastonite fiber is 10 to 50% by weight, though it depends on the type of the resin.

Further, in the present invention, various additives can be appropriately compounded within a range that does not impair the purpose. For example, there are antioxidants, ultraviolet absorbers, heat stabilizers, lubricants, antistatic agents, coloring agents, antibacterial agents, flame retardants, lubricants, elastomers for improving impact resistance, and low hardness talc, mica, barium sulfate. And a filler such as pyrophyllite.

In producing the resin composition of the present invention, a known method can be used. For example, a thermoplastic resin and necessary additives are mixed by a tumbler or various mixers and the like, fed and melted from a hopper of a twin-screw kneading extruder, and kneaded by supplying wollastonite from the middle of the extruder, Pellets can be granulated.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, according to Examples and Comparative Examples,
The present invention will be described in more detail. Examples and comparative examples were evaluated by the following methods. ASTM flexural strength and flexural modulus
-D790, tensile strength and elongation were measured according to ASTM-D639, impact strength was measured according to JIS-K7113 with notch, and MFR (melt flow rate) was measured according to ASTM-D1238.
Further, the surface roughness was measured using Surfcom-474A (Tokyo Seimitsu) and displayed as average roughness Ra, and the whiteness was measured using a colorimetric color difference meter (Nippon Denshoku ND300A type).
Indicated by a, b, and W. Three types of wollastonite and potassium titanate whisker 2 used in Examples and Comparative Examples
The following types were used.

Wollastonite W1: Fe ₂ O ₃ : 0.
Wollastonite having a fiber length of 20 to 50 μm, a fiber diameter of 0.5 to 5 μm, and an average aspect ratio of 7 to 100, containing 5% by weight or less and Al ₂ O ₃ : 0.49% by weight or less. Crushed and classified by Kawairon Mining Co., Ltd. W
FIG. 1 shows an SEM photograph of a 1 magnification of 300 times.

Wollastonite W2: Fe ₂ O ₃ : 0.
5-1 wt% and _Al 2 _O 3: contains 0.1 to 0.5 wt%, average fiber length 250μm wollastonite having an average fiber diameter of 35 [mu] m, fibers commercially available in the United States with an average aspect ratio of 7 Shaped thing. FIG. 2 shows an SEM photograph of W2 at a magnification of 150 times.

Wollastonite W3: Wollastonite having an average fiber length of 24 μm, an average fiber diameter of 10 μm, an average aspect ratio of 2.4, and an average particle size of 10 μm, and has low fibrousness conventionally marketed in the United States. An SEM photograph of W3 at a magnification of 300 is shown in FIG.

Potassium titanate whisker 1: manufactured by Kawairon Mining Co., Ltd. (trade name: TBREX, H type), having an average fiber length of 20 μm, an average fiber diameter of 10 μm, and an average aspect ratio of 33.

Potassium titanate whisker 2: manufactured by Kawairon Mining Co., Ltd. (trade name is TBREX, S type), and the size is the same as the above H type.

Examples 1 to 3 and Comparative Examples 1 to 5 As polyamide 66 (PA66), Zytel 101 was used.
(Manufactured by DuPont) was used. A predetermined amount of filler is supplied from the side feed port of the twin screw extruder (Toshiba Machine TEM35B) to the above resin, and after melt-kneading at a temperature of 300 ° C,
Pelletized by strand cutting. These pellets were injection-molded at a cylinder temperature of 290 ° C. and a mold temperature of 80 ° C. using an injection molding machine (Sumitomo Heavy Industries Plastic Machinery SH75) to measure physical properties. Table 1 shows the results.

Wollastonite W1 shown in Examples 1 to 3
The blended product is superior to wollastonite W2 conventionally marketed in all physical properties such as flexural strength, flexural modulus, tensile strength, elongation, impact value, MFR, surface roughness and whiteness. In addition, W3 is excellent except for elongation at break. On the other hand, as compared with the potassium titanate whisker compound, the elongation and the impact value are excellent, and the surface roughness is low but close. Further, wollastonite has no hiding power unlike potassium titanate whiskers, and thus is easily colored. Therefore, it can be seen that wollastonite W1 of the present invention is a very good reinforcing filler.

Examples 4 to 6, Comparative Examples 6 to 10 As polybutylene terephthalate (PBT), Duranex 2000 (made of polyplastic) was used. Similarly to PA66, the mixture was melt-kneaded at a temperature of 250 ° C. and pelletized. These pellets are placed at a cylinder temperature of 250
Injection molding was performed at 80 ° C. and a mold temperature of 80 ° C., and physical properties were measured. Table 2 shows the results. The effect of blending shows the same tendency as PA66. That is, in the examples, the blending effects were all better than those of wollastonite W2 and W3 which were conventionally commercially available, but there was no difference as much as PA66 as compared with the effect of potassium titanate whiskers. However, the value of MFR is very large, and high blending can be expected.

Examples 7 to 9 and Comparative Examples 11 to 15 As polycarbonate (PC), Iupilon 200 was used.
0 (manufactured by Mitsubishi Engineering Plastics) was used. Pellets were prepared by melting and kneading at a temperature of 300 ° C. as in the case of the two resins in the above example, and injection molding was performed at a cylinder temperature of 300 ° C. and a mold temperature of 80 ° C. to measure physical properties. Table 3 shows the results.

Even if the wollastonite W1 of the present invention is mixed with the non-crystalline resin PC, the crystalline resins PA66 and PB
It showed almost the same physical properties as T. Accordingly, the wollastonite W1 of the present invention is different from the wollastonite W2, W3
It can be seen that the filler is excellent in the reinforcing effect and coloring property and can be used for various applications.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

Industrial Applicability The thermoplastic resin article of the present invention can provide a molded article having high rigidity, high strength, excellent surface smoothness, excellent dimensional stability, and good appearance with good coloring. Therefore, it can be used for a wide range of applications, such as production of various molded products, for example, molded products in the OA equipment, electric / electronic fields, the automobile field, the mechanical field, and the building materials field.

[Brief description of the drawings]

FIG. 1 is a SEM photograph at a magnification of 300 of wollastonite W1 used in Examples.

FIG. 2 is an SEM photograph of Wollastonite W2 used in Comparative Example at a magnification of 150 times.

FIG. 3 is an SEM photograph of Wollastonite W3 used in Comparative Example at a magnification of 300 times.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoru Mita 2-17-4 Kuramae, Taito-ku, Tokyo Kawairon Mining Co., Ltd. (72) Inventor Masamichi Matsumoto 2-17-4 Kuramae, Taito-ku, Tokyo F-term (reference) in Iron Mining Co., Ltd. 4J002 AA011 CF071 CG011 CL031 DJ006 FA046 FD010 FD016

Claims (3)

[Claims] 1. Wollastonite as a main component and Fe ₂ O
₃ : 0.5% by weight or less and Al ₂ O ₃ : 0.49% by weight
A resin composition comprising: a wollastonite fiber containing the following; and a thermoplastic resin. 2. The resin composition according to claim 1, wherein the wollastonite fiber has an average fiber length of 20 to 50 μm, an average fiber diameter of 0.5 to 5 μm, and an average aspect ratio of 7 to 100. object. 3. The resin composition according to claim 1, comprising 5 to 70% by weight of a fiber mainly composed of wollastonite and 95 to 30% by weight of a thermoplastic resin.