JP2004035635A - PPS resin composition with excellent release properties - Google Patents

Abstract

An object of the present invention is to provide a resin composition having excellent mold releasability when injection molding is performed.
A resin composition comprising a polyphenylene sulfide-based resin composition and a non-crystalline α-olefin copolymer and a fatty acid metal salt in a combined amount of 0.2 to 3.0% by mass.
[Selection diagram] No selection diagram

Description

【００１８】
【発明の効果】
本発明のポリフェニレンサルファイド系樹脂組成物は、離型性に優れる為、複雑な射出成形品形状に対応でき、形状設計の自由性を広げる事が可能となる。離型性向上の為に非結晶性α−オレフィン共重合体と脂肪酸金属塩を併用配合することにより、相乗効果が生じ、添加量を低減できると共に安定、且つ優れた離型性を保持できることから、価格的にも、性能的にもポリフェニレンサルファイド系樹脂の射出成形時における離型性向上の市場ニーズに十分応えるものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polyphenylene sulfide-based resin composition having improved mold release properties.
[0002]
[Prior art]
With the diversification and complexity of the shape of resin products, market needs for a resin composition having excellent moldability and releasability are increasing. Conventionally, as a method of improving the mold releasability of a resin, a method of adding a fatty acid, a metal salt thereof, a wax, or the like to a resin as a lubricant is generally used. However, these lubricants generally have poor thermal stability, and particularly when a large amount is added, when the resin composition is molded at a high temperature, an appearance defect is generated by a decomposition gas or the like, or the effect is reduced by decomposition. And so on.
Particularly, in the case of the polyphenylene sulfide-based resin composition, the molding temperature and the mold temperature may be increased, and the problem of mold release failure often occurs at the time of molding. However, the release property of the polyphenylene sulfide resin-based resin composition is reduced. At present, there has not yet been provided on the market a release prescription which does not cause problems such as poor appearance, poor peeling, and deterioration of physical properties, and which exhibits a large release improvement effect when added in a small amount.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a polyphenylene sulfide-based resin composition having excellent mold release properties upon injection molding.
[0004]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, a polyphenylene sulfide-based resin composition in which a non-crystalline α-olefin copolymer and a fatty acid metal salt are combined and used, the releasability is dramatically improved. The inventors have found that the present invention is improved, and have accomplished the present invention.
That is, the present invention is characterized in that a polyphenylene sulfide-based resin composition is combined with a non-crystalline α-olefin copolymer and a fatty acid metal salt in a total amount of 0.2 to 3.0% by mass. It is a resin composition having excellent mold release properties.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be specifically described below.
The resin composition of the present invention is a resin composition obtained by combining a non-crystalline α-olefin copolymer and a fatty acid metal salt with a polyphenylene sulfide (hereinafter abbreviated as PPS) resin composition.
The PPS-based resin composition of the present invention is a PPS resin alone or a polymer alloy of PPS and another resin, wherein the polymer alloy of PPS and another resin is PPS / polyphenylene ether alloy, PPS / polycarbonate alloy, Examples include PPS / polyphenylene ether / polystyrene alloy, PPS / polyphenylene ether / high impact polystyrene alloy, and the like.
[0006]
The structure of the PPS resin referred to here may be any of a straight-chain structure and a branched structure, and may be a mixture of these structures.
Further, these PPS resin compositions include polybutadiene, polyisoprene, styrene-butadiene copolymer, butadiene-isoprene copolymer, hydrogenated styrene-butadiene block copolymer, hydrogenated styrene-isoprene block copolymer, and the like. May be blended.
Examples of the non-crystalline α-olefin copolymer which is a compounding component include an ethylene-propylene copolymer and an ethylene-butene copolymer, and the use of an ethylene-propylene copolymer is particularly preferable. Examples of the fatty acid metal salt include magnesium stearate and zinc stearate, and it is particularly preferable to use magnesium stearate.
[0007]
The amount of these compounds is 0.2 to 3.0% by mass as the total amount of the non-crystalline α-olefin copolymer and the fatty acid metal salt, based on the total amount of the composition after compounding, and 0.3 to 3.0% by mass. It is preferable to mix 2.0 mass%, and it is especially preferable to mix 0.5 to 1.1 mass%. When the total amount of the non-crystalline α-olefin copolymer and the fatty acid metal salt is less than 0.2% by mass, there is almost no effect of improving the releasability, and the total amount exceeds 3.0% by mass. In such a case, molding defects such as poor appearance of the molded product and deterioration of physical properties may occur, which is not preferable. About the compounding amount of each component, the compounding amount of the amorphous α-olefin copolymer is preferably 0.15 to 2.0% by mass, more preferably 0.4 to 1.0% by mass. It is. When the amount of the amorphous α-olefin copolymer is less than 0.15% by mass, the effect of improving the releasability is not sufficient, and the amount of the α-olefin copolymer exceeds 2.0% by mass. In addition, defective phenomena such as poor appearance of the molded product and poor peeling may occur, which is not preferable. The compounding amount of the fatty acid metal salt is preferably from 0.02 to 1.0% by mass, and particularly preferably from 0.03 to 0.5% by mass. If the amount of the fatty acid metal salt is less than 0.02% by mass, the effect of improving the releasability by the combined use of the non-crystalline α-olefin copolymer and the fatty acid metal salt is insufficient, and the amount of the fatty acid metal salt is reduced. If the content exceeds 1.0% by mass, appearance defects and the like are likely to occur, which is not preferable.
[0008]
The effect of the combination of these non-crystalline α-olefin copolymers and fatty acid metal salts is that, when injection-molded, an incompatible soft non-crystalline α-olefin polymer is present in the vicinity of the outermost layer of the molded product in a minute dispersion. By doing so, the elastic modulus in the vicinity of the very surface of the molded article decreases. By this, it is assumed that the molded product interface that comes into contact with the mold at the time of mold release is slightly deformed, and the molded product is easily released from the mold. It is also assumed that the fatty acid metal salt used in combination is selectively incorporated into the non-crystalline α-olefin copolymer and exerts an effect when reducing the friction between the surface of the molded article and the mold during mold release.
[0009]
The resin composition of the present invention is a mixture of a non-crystalline α-olefin copolymer and a fatty acid metal salt. The synergistic effect of friction reduction dramatically improves the releasability.
The mixing of the resin composition constituting the present invention can be achieved by a conventionally known technique such as dry blending, an extruder, a heating roll, a Banbury mixer, and a kneader, and these can be used in combination. Mixing by machine. Further, it is also preferable that after mixing the PPS resin composition and the non-crystalline α-olefin copolymer with an extruder, mixing is performed by dry-blending the obtained pellets with a fatty acid metal salt. .
[0010]
Other additives, such as plasticizers, stabilizers, antistatic agents, ultraviolet absorbers, flame retardants, colorants, and glass fibers, carbon fibers, to the extent that the invention is not impaired, is included in the resin composition constituting the present invention. And fibrous reinforcing agents such as potassium titanate whiskers and zinc oxide whiskers, and fillers such as glass beads, glass flakes, mica, calcium carbonate and talc.
The present invention will be described based on examples, but the present invention is not limited to the following examples.
[0011]
The components used in Examples and Comparative Examples are as follows, and were melt-kneaded in an extruder, and injection molding of the obtained pellets was performed to evaluate the releasability and the presence or absence of resin surface peeling. Carried out.
1) Polyphenylene sulfide resin melt viscosity (value measured after holding for 6 minutes at 300 ° C., load of 20 kgf / cm ² , L / D = 10/1 using a flow tester) is 50 (Pa · s). Polyphenylene sulfide having a linear structure.
2) Polyphenylene ether resin Poly 2,6-dimethyl-1,4-phenylene ether having an intrinsic viscosity [η] of 0.52 (30 ° C. in chloroform) (density: 1.06 g / cm ³ )
[0012]
3) Styrene-glycidyl methacrylate copolymer containing 5% by weight of compatibilizer glycidyl methacrylate (weight average molecular weight 110,000)
4) Ethylene-propylene copolymer manufactured by Mitsui Chemicals, Inc., Tuffmer P0680J
5) Magnesium stearate manufactured by Dainichi Chemical Co., Ltd. 6) Fibrous reinforcing filler: glass fiber RES03-TPO15 (manufactured by Nippon Sheet Glass Co., Ltd.)
7) Flake-like inorganic filler: glass flake micro glass flicker REFG-302 (manufactured by Nippon Sheet Glass)
[0013]
In addition, the evaluation method of mold release property and resin surface peeling property is as follows.
(1) Releasability A cup-shaped molded product having an outer diameter of 50 mm, a height of 50 mm, and a thickness of 3 mm was injection-molded, and a load required for projecting the molded product was measured as a releasing force.
(2) The presence or absence of resin surface peeling of the molded article was visually checked.
[0014]
Examples 1 and 2
The components of the polyphenylene sulfide resin, glass fiber, and non-crystalline α-olefin copolymer (ethylene-propylene block copolymer) and fatty acid metal salt (magnesium stearate) having the composition shown in Table 1 were subjected to a temperature of 290 to 320 ° C. The mixture was melt-kneaded with a twin-screw extruder (ZSK-40: manufactured by Werner & Pfleidere) set at a screw rotation number of 500 rpm to obtain a composition pellet. The obtained resin pellets were subjected to injection molding (resin temperature 310 ° C., mold temperature 140 ° C.) to evaluate the releasability and the presence or absence of resin surface peeling. Table 1 shows the evaluation results.
[0015]
Embodiments 3 and 4
Each component of the polyphenylene sulfide resin, polyphenylene ether resin, compatibilizer, glass fiber, glass flake, and amorphous α-olefin copolymer (ethylene-propylene block copolymer) having the composition shown in Table 1 was heated to a temperature of 290 to 290. The mixture was melt-kneaded with a twin-screw extruder (ZSK-40: manufactured by WERNER & PFLEIDERE) set at 320 ° C and a screw rotation number of 500 rpm to obtain a composition pellet. After the fatty acid metal salt (magnesium stearate) is dry-blended to the obtained resin pellets, injection molding (resin temperature 310 ° C., mold temperature 140 ° C.) is performed to evaluate the releasability and the presence or absence of resin surface peeling. Done. Table 1 shows the evaluation results.
[0016]
[Comparative Examples 1 to 6]
Comparative Examples 1 and 2 show the releasability when no additive was added to the same resin composition as in Examples 1 and 3. Comparative Examples 3 and 4 show the releasability when only the amorphous α-olefin copolymer or the fatty acid metal salt was used alone, and both were not used.
Not only when the non-crystalline α-olefin copolymer and the fatty acid metal salt are not blended, but also when compared with the case where the non-crystalline α-olefin copolymer and the fatty acid metal salt are blended alone without using together, the releasing force of the examples is significantly reduced. It can be seen that good releasability was exhibited.
Comparative Example 5 shows the result when the non-crystalline α-olefin copolymer and the fatty acid metal salt were blended in a total amount of less than 0.2% by mass, but the effect of improving the releasability was not sufficiently exhibited. . Also, the results when Comparative Example 6 was added with an amorphous α-olefin copolymer in an amount exceeding 2.0% and a fatty acid metal salt in an amount exceeding 1.0% were shown. Although the releasability was good, peeling was observed on the resin surface of the molded product.
[0017]
[Table 1]

[0018]
【The invention's effect】
The polyphenylene sulfide-based resin composition of the present invention is excellent in releasability, so that it can cope with a complicated injection molded product shape and expand the freedom of shape design. By combining the non-crystalline α-olefin copolymer and the fatty acid metal salt in combination for the purpose of improving the releasability, a synergistic effect occurs, the amount of addition can be reduced, and the stable and excellent releasability can be maintained. The present invention sufficiently meets the market needs for improving the releasability in injection molding of a polyphenylene sulfide-based resin in terms of price and performance.

Claims (2)

A resin composition comprising a polyphenylene sulfide resin composition and a non-crystalline α-olefin copolymer and a fatty acid metal salt in a combined amount of 0.2 to 3.0% by mass. The polyphenylene sulfide-based resin is a polymer alloy of polyphenylene sulfide and polyphenylene ether, the amorphous α-olefin copolymer is an ethylene-propylene copolymer, and the fatty acid metal salt is magnesium stearate. 3. The resin composition according to item 1.