JPH06104758B2 - Thermoplastic composition for injection molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a non-crystalline thermoplastic resin composition for injection molding which can give a molded article having excellent dimensional accuracy. More specifically, the present invention is made by blending a scale-like glass frame or glass flakes and a reinforcing filler to a non-crystalline resin, has little warpage by injection molding, and has a molding shrinkage ratio and a linear expansion coefficient. The present invention relates to a non-crystalline thermoplastic resin composition capable of giving a molded article which is remarkably improved and which is excellent in mechanical properties, appearance and colorability.

2. Description of the Related Art In recent years, in the fields of automobiles, office equipment, electric appliances, etc., it has been attempted to replace some of the parts, especially sheet metal, with engineering resin products for the purpose of weight saving, energy saving, and cost reduction. As a result, there is an increasing demand for engineering resins, especially engineering resins reinforced with toughening agents. For example, a polyamide resin which is a crystalline resin, a polyester resin, a resin composition in which glass fibers are mixed with a polyacetal resin to improve heat resistance and rigidity, a polycarbonate resin which is an amorphous resin, a polyphenylene ether resin, A resin composition in which glass fiber is mixed with ABS resin to improve heat resistance and rigidity has been proposed.

However, a fibrous material as a reinforcing agent, for example, these resin compositions prepared by blending glass fibers have good rigidity, heat resistance, appearance, and colorability, but since the glass fibers have directionality, When manufacturing a plate-shaped molded product by injection molding, there is a drawback that the molded product is warped and has anisotropy of linear expansion coefficient (ratio of linear expansion coefficients in the flow direction and the perpendicular direction). These warpage and anisotropy of linear expansion coefficient cause deterioration of physical properties and thermo-thermal properties for engineering resins for the purpose of replacing sheet metal and aluminum die casting, and also reduce product value. It is also a big factor to make it.

Therefore, in the engineering resin filled with the reinforcing agent, various researches have been conducted on the improvement of the anisotropy of the warpage and the coefficient of linear expansion, and especially the suppression of the warpage, for example, a thermoplastic resin containing a short fibrous inorganic filler. Resin composition (JP-A-53-35749), a resin composition comprising a solid polymer and a reinforcing mica substance (JP-B-49-18615), polyethylene terephthalate resin And a fibrous reinforcing filler and a glass foil (Japanese Patent Publication No. 60-17222), a resin composition obtained by blending an aromatic polyester with flat glass flakes (Japanese Patent Publication No. 17223). Is disclosed.

However, these resin compositions, when used as a substitute for, for example, aluminum die casting, can achieve the purpose of energy saving and cost reduction by reducing the weight and omitting secondary processing, and also flexural modulus, Izod impact strength, Although it is almost satisfactory in terms of mechanical properties such as heat distortion temperature, improvement in dimensional accuracy, such as warpage, molding shrinkage, and linear expansion coefficient, is not always sufficient, and the appearance and It is also inferior in colorability and subject to restrictions on its use.

In particular, in the combination of the crystalline resin and the reinforcing filler, the crystallization of the crystalline resin causes volumetric shrinkage and shrinkage due to linear expansion, which cause mold shrinkage.
In addition, since the reinforcing filler is oriented in the resin flow direction, anisotropy of shrinkage occurs depending on the direction, and generally accepted warpage occurs, as well as improvement of molding shrinkage and linear expansion coefficient. Not enough.

Problems to be Solved by the Invention Under such circumstances, the object of the present invention is to further improve the dimensional stability inherent in the amorphous thermoplastic resin, and to provide excellent mechanical properties and electrical properties. Another object of the present invention is to provide a non-crystalline thermoplastic resin composition having excellent dimensional accuracy, which is suitable as a substitute for sheet metal, in addition to a molded product having excellent appearance and colorability.

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object, and as a result, with respect to the non-crystalline thermoplastic resin, scale glass flakes alone or with the glass flakes. It has been found that the purpose can be achieved by blending with a reinforcing filler, and the present invention can be completed based on this finding.

That is, in the present invention, the maximum diameter (L) is 1000 μm or less and the maximum diameter (L) is 100 parts by weight of the amorphous thermoplastic resin.
The present invention provides a thermoplastic resin composition for injection molding, comprising 5 to 150 parts by weight of scaly gaas flakes having a ratio (L / D) of 5 to 5 in thickness (D).

Examples of the amorphous thermoplastic resin used in the composition of the present invention include aromatic polyphenylene ether resins, polycarbonate resins, polystyrene resins, rubber-modified polystyrene resins, styrene-acrylonitrile copolymer resins, rubber-modified styrene-acrylonitrile copolymers. There is no particular limitation as long as it is a non-crystalline resin such as a coalescing resin or a styrene-maleic anhydride copolymer resin, but from the viewpoint of improving heat resistance and dimensional accuracy, aromatic polyphenylene ether resin or polycarbonate. Resins or polyblends of these and styrene resins are particularly suitable.

The glass flakes used in the composition of the present invention are flaky, have a maximum diameter after resin blending of 1000 μm or less, preferably in the range of 1 to 500 μm, and have an aspect ratio (ratio between maximum diameter and thickness) of 5 Or more, preferably 10 or more,
More preferably, it is 30 or more. As the glass flakes, commercially available ones can be used as they are, but they may be appropriately crushed and used when blended with a resin.

If the glass flakes have a maximum diameter of 1000 μm,
Classification may occur at the time of compounding, which makes it difficult to uniformly mix with the resin, and may cause unevenness in the physical properties of the molded product. on the other hand,
Those having an aspect ratio of less than 5 are not preferable because the heat distortion temperature of the molded product is insufficiently improved and the Izod impact strength tends to decrease.

In the composition of the present invention, the amount of the glass flakes used is 5 parts by weight based on 100 parts by weight of the amorphous thermoplastic resin.
To 150 parts by weight, preferably 20 to 100 parts by weight, more preferably 30 to 70 parts by weight. If this amount is less than 5 parts by weight, the improvement of the coefficient of linear expansion will be insufficient,
If it exceeds 150 parts by weight, uniform mixing is difficult and moldability and appearance of the composition are deteriorated. And, especially when the amount of the glass flakes used is in the range of 30 to 70 parts by weight, significant improvement is observed in thermal properties, mechanical properties, dimensional accuracy (warpage, molding shrinkage, linear expansion coefficient), etc. To be

Further, as the glass flakes, glass flakes surface-treated with various coupling agents such as silane type and titanate type can be used for the purpose of improving the affinity with the resin.

In the composition of the present invention, in addition to the scaly glass flakes, a granular or short fiber reinforcing filler can be further contained. Examples of such a reinforcing filler include glass fiber, carbon fiber, ceramic fiber,
Examples of the filler include short fiber reinforcing fillers such as metal fibers and inorganic particles such as glass beads, and these reinforcing fillers are preferably used in an amount of 50% by weight or less based on the glass flakes. If the ratio of the short fiber reinforced filler exceeds 50% by weight, the dimensional accuracy (warpage, molding shrinkage ratio, linear expansion coefficient) cannot be improved sufficiently, and if the amount of inorganic particles exceeds 50% by weight, the rigidity decreases. Is not preferred.

In the present invention, the method of blending the amorphous thermoplastic resin and the glass flakes alone or the glass flakes and the reinforcing filler in the form of granules or short fibers is not particularly limited and any method can be used. For example, a method of adding the glass flakes alone or the glass flakes and other reinforcing filler to the amorphous thermoplastic resin in the molten state and mixing them, the amorphous thermoplastic resin and the glass flakes alone or the glass flakes Any method can be used as long as it is generally a method of melt-mixing, such as a method of previously mixing with other reinforcing filler and then melt-mixing.

In the composition of the present invention, a flame retardant such as a halogen-based or phosphoric acid ester-based, a flame-retardant aid such as antimony trioxide, a phenol-based, a phosphorus-based, an antioxidant such as a hindered phenol-based, a stabilizer, if desired. Colorants such as titanium oxide and carbon black, lubricants such as metallic soap, fluidity modifiers, reinforcing thermoplastic elastomers such as styrene-butadiene block type, polyester type, polyesteramide type, etc. can be added in the required amounts. .

Advantageous Effects of Invention The amorphous thermoplastic resin composition of the present invention comprises an amorphous thermoplastic resin in which flaky glass flakes or the glass flakes and granular or short fibrous reinforcing filler are blended. , High heat distortion temperature, excellent mechanical properties, less warpage, and improved molding shrinkage and linear expansion coefficient, resulting in significantly improved dimensional accuracy and good appearance and colorability. . Therefore, it is preferably used as an engineering resin for replacing sheet metal in automobiles, electric products, office equipment and the like.

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The characteristics of the resin composition are IS-80AM manufactured by Toshiba Machine Co., Ltd.
Using injection molding machine, cylinder temperature 300 ℃, mold temperature 8
Test pieces were prepared at 0 ° C and evaluated according to the following test methods.

(1) Heat distortion temperature: ASTM-D648 (2) Flexural modulus: ASTM-D790 (3) Izod impact strength: ASTM-D256, 1/4 "thick, with notch (4) Molding shrinkage rate: ASTM-D955 , 150 × 150 × 3mm flat plate,
The shrinkage ratio is preferably 0.4% or less.

(5) Flame retardancy: UL-94, 1/8 "test piece used (6) Warpage: Measure the maximum warpage (mm) with a clearance gauge using a 150 x 150 x 3 mm flat plate. The smaller the number, the better the dimensional accuracy.

(7) Melt flow rate: Melt indexer MX-101A manufactured by Takara Kogyo was used, and the outflow rate (g) was obtained after holding for 10 minutes at 250 ° C. and a load of 2 kg. The larger the value, the better the fluidity.

(8) Dyeability and gloss: A 150 × 150 × 3 mm flat plate was used and visually judged.

(9) Coefficient of linear expansion Strain was removed by annealing and the test piece pretreated by the method of ASTM-D618 was used to determine the coefficient of linear expansion of the resin in the flow direction and in the direction perpendicular to the flow direction. , Resistance wire strain gauge, according to the method of ASTM-D696 -35 ~ 6
It was measured between 5 ° C.

The anisotropy of the linear expansion coefficient used in the present invention is a value obtained by dividing the linear expansion coefficient in the perpendicular direction by the linear expansion coefficient in the flow direction. It can be said that a resin composition having a value closer to 1 has less anisotropy. The engineering resin for sheet metal substitution must have anisotropy of 2 or less.

Examples 1 to 4 Poly (2,6-dimethyl-1,4-phenylene) ether having an intrinsic viscosity of 0.62 (in chloroform at 25 ° C.) as a non-crystalline thermoplastic resin, a rubber-modified styrenic resin Styron QH405 (manufactured by Asahi Kasei Kogyo Co., Ltd.) , Styrene-maleic anhydride copolymer Dailark 232 (manufactured by Arco) and polystyrene resin Styron GP685 (manufactured by Asahi Kasei Corporation), triphenyl phosphate as a phosphoric acid ester flame retardant, and mark AO-30 as a stabilizer ( Adeka Argus Co., Ltd.), RES03-TP68 (Nippon Sheet Glass Co., Ltd.) as glass fiber, CEF048A, CEF150A (Nippon Sheet Glass Co., Ltd.) as glass flakes at the ratios shown in the table, and a 30φ twin-screw extruder (NAKATANI) Machinery, AS-30φ) was used to extrude and knead at 280 ° C. and a discharge rate of 10 kg / hr to prepare pellets, and the physical properties of the pellets were determined. The results are shown in the table.

Examples 5 to 7 Acrylonitrile-styrene-butadiene copolymer resin Styrac 181H (manufactured by Asahi Chemical Industry Co., Ltd.) as a non-crystalline thermoplastic resin, polymer blend resin Multilon T-1000 (manufactured by Teijin Chemicals Co.) of polycarbonate resin and ABS resin And polycarbonate resin Panlite K-1300 (manufactured by Teijin Chemicals), Mark AO-30 (manufactured by ADEKA ARGUS) as a stabilizer, and CEF150A (manufactured by Nippon Sheet Glass Co., Ltd.) as glass flakes in a mixing ratio as shown in the table Using a 30φ twin-screw extruder (manufactured by Nakatani Machinery Co., Ltd.), 300 ° C, discharge rate 10 kg /
Extrusion and kneading were carried out under the condition of hr to prepare pellets, and the physical properties of the obtained resin composition were determined. The results are shown in the table.

Comparative Examples 1, 2 and 4 Polyethylene terephthalate resin as a crystalline polymer (crystal melting point: 265 ° C., 25 ° C .: 0.4 dl / K in o-chlorophenol)
g), polybutylene terephthalate resin Toray PBT1401 × 06
As glass fiber, RES03-68 (made by Nippon Sheet Glass Co., Ltd.)
, CEF048A, CEF150A (manufactured by Nippon Sheet Glass Co., Ltd.) as glass flakes in the proportions shown in the table, using an AS-30φ twin-screw extruder (manufactured by Nakatani Machinery Co., Ltd.), 300 ° C., discharge rate 10 Kg / hr Extrusion kneading was carried out under the conditions described above to prepare pellets, and the physical properties of the obtained resin composition were determined. The results are shown in the table.

As can be seen from this table, Comparative Example 1 is not preferable because it has larger warpage, molding shrinkage, linear expansion coefficient and its anisotropy than Example 1. In Comparative Example 2, although warpage, molding shrinkage and linear expansion coefficient are considerably improved as compared with Comparative Example 1, compared with Example 1, since the crystalline resin is the base, the warpage is insufficient. Is not preferable.

Comparative Examples 3,5,6,7 Poly (2,6-dimethyl-1,4-phenylene) having an intrinsic viscosity of 0.62 (in chloroform at 25 ° C.) as a non-crystalline thermoplastic resin
Ether, high impact polystyrene resin Stylon QH405
(Made by Asahi Kasei Corporation) and polystyrene resin Styron GP
Mark 685 (made by Asahi Kasei Co., Ltd.) as a flame retardant and triphenyl phosphate (made by Daihachi Chemical Co., Ltd.) as a stabilizer
AO-30 (made by ADEKA ARGUS) is used as glass fiber in RES
03-TP68 (manufactured by Nippon Sheet Glass Co., Ltd.), Torayca T006 (manufactured by Toray) as carbon fiber, Suzulite Mica 200KI (manufactured by Kuraray) as flake filler, and glass beads EGB731A (manufactured by Toshiba Ballotini) as spherical filler. Was used in the proportions shown in the table, and using AS-30φ twin-screw extruder (manufactured by Nakatani Machinery Co., Ltd.), extrusion kneading was performed under the conditions of 280 ° C. and a discharge rate of 10 kg / hr to prepare a pellet. The physical properties of the resin composition were measured. The results are shown in the table.

As can be seen from this table, Comparative Example 3 is warped as compared with Example 1, the molding shrinkage ratio and the linear expansion coefficient are insufficient, and the appearance gloss is also inferior. Comparative Example 5 is comparable to Example 1 in warpage, molding shrinkage, and linear expansion coefficient, but is not preferable because the resin becomes blackish brown and impact strength and appearance gloss are significantly reduced.

In Comparative Example 6, glass fibers and glass beads were mixed and added as compared with Example 1, so that the warpage, the bending elastic modulus, and the molding shrinkage ratio were insufficient, which is not preferable.

In Comparative Example 7, since glass fibers and carbon fibers were mixed and added, the warpage, the molding shrinkage rate, the linear expansion coefficient, and the appearance gloss were inferior to those of Example 1, and the results were insufficient.

Claims (1)

[Claims] 1. Scales having a maximum diameter (L) of 1000 μm or less and a ratio (L / D) of the maximum diameter (L) to the thickness (D) of 5 or more with respect to 100 parts by weight of an amorphous thermoplastic resin. A thermoplastic resin composition for injection molding, comprising 5 to 150 parts by weight of glass flake.