JP2002020629A - Resin composition excellent in mold release - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition excellent in a mold release during injection molding. SOLUTION: This composition is prepared by compounding both a non- crystalline α-olefin copolymer (A) and a fatty acid metal salt (B) into a resin composition mainly composed of a non-crystalline resin, and the total of (A) and (B) is 0.3-3.0 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-crystalline resin composition having improved mold release properties and a molded article produced from the resin composition.

[0002]

2. Description of the Related Art With the diversification and complexity of resin products, especially in the fields of electric and electronic parts and automobile parts, market needs for resin compositions having good moldability and releasability are increasing. In particular, electrical and electronic field parts such as switchboard parts, deflection yoke, flyback transformer, connectors, battery case, adapter case, chassis, etc., meter hood,
In the automotive field components such as the center cluster and the ignition coil bobbin, the shape is complicated, so that there is a great demand for improving the releasability.

Conventionally, as a method for improving the mold releasability of a resin, a method in which a fatty acid, a metal salt thereof, a wax or the like is added to the resin as a lubricant is generally used. However, the releasability of the resin composition containing these lubricants is
In the case of a molded article having a complicated shape, it may not be sufficient, and it may be necessary to take measures under molding conditions such as restriction of the shape of the molded article and extension of the cooling time. In addition, when these lubricants are added in a particularly large amount, poor appearance due to deterioration of mechanical properties, generation of decomposition gas when the resin composition is molded at a high temperature, and separation of the additive components are caused. There is a problem that the mold effect is weakened.There is no mold release formulation that does not cause problems such as poor appearance, poor peeling, and deterioration in physical properties, and that exhibits a large mold release improvement effect by adding a small amount. Is the current situation.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition and a molded article having excellent mold releasability upon injection molding.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a resin composition containing a non-crystalline α-olefin copolymer and a fatty acid metal salt in combination has been released. The inventors have found that the properties are dramatically improved, and have accomplished the present invention. That is, the present invention provides: A composition comprising (A) a non-crystalline α-olefin copolymer and (B) a fatty acid metal salt in combination with a resin composition containing a non-crystalline resin as a main component, wherein (A) and (B) Is a total amount of 0.3 to 3.0% by weight.

[0006] 2. 2. The thermoplastic resin composition according to the above item 1, wherein the non-crystalline resin is a polyphenylene ether-based resin or a resin composition containing a polyphenylene ether-based resin and a styrene-based resin as main components. 3. (A) The amorphous α-olefin copolymer is ethylene-
3. The thermoplastic resin composition according to any one of the above items 1 or 2, which is a propylene copolymer.

[0007] 4. (B) The thermoplastic resin composition according to any one of (1) to (3) above, wherein the fatty acid metal salt is a stearic acid metal salt. 5. (B) The thermoplastic resin composition according to any one of (1) to (4) above, wherein the fatty acid metal salt is magnesium stearate. 6. A molded article produced by injection molding the thermoplastic resin composition according to any one of the above 1 to 5.

[0008]

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) a non-crystalline α-olefin copolymer and (B) a fatty acid metal salt with an amorphous resin composition. Examples of the non-crystalline resin used in the present invention include PS (polystyrene), styrene / butadiene copolymer, ABS (acrylonitrile / butadiene / styrene copolymer), SAN (styrene / acrylonitrile copolymer), PC (polycarbonate), PC / ABS, and denatured resin. PPE (polyphenylene ether), PEI (polyetherimide), PSF (polysulfone), PES (polyethersulfone) and the like.

The non-crystalline α-olefin copolymer (A), which is a compounding component, includes ethylene-propylene copolymer,
Ethylene-butene copolymer and the like can be mentioned,
It is particularly preferable to use an ethylene-propylene copolymer. The (B) fatty acid metal salt is not particularly limited, but is preferably a metal salt composed of a fatty acid having 15 to 30 carbon atoms, and more preferably a metal salt composed of a fatty acid having 15 to 20 carbon atoms. Further, stearic acid metal salts are preferred,
Among them, magnesium stearate and zinc stearate are preferred, and the use of magnesium stearate is particularly preferred.

The compounding amount is 0.1% as the total amount of (A) the amorphous α-olefin copolymer and (B) the fatty acid metal salt.
The content is 3 to 3.0% by weight, preferably 0.5 to 2.2% by weight, more preferably 0.7 to 2.0% by weight, and still more preferably 1.2 to 1.8% by weight. If the total amount is less than 0.3% by weight, the releasability improving effect cannot be sufficiently exhibited. Regarding the amount of each component, the amount of (A) the amorphous α-olefin copolymer is preferably 0.2 to 2.0% by weight, more preferably 0.3 to 2.0% by weight.
It is 1.5% by weight, more preferably 0.4 to 1.2% by weight. If the amount exceeds 2.0% by weight, undesired phenomena such as poor appearance of the molded article and poor peeling may occur. (B) The compounding amount of the fatty acid metal salt is 0.1 to 1.
The content is preferably 0% by weight, more preferably 0.2 to 0.8% by weight, and still more preferably 0.3 to 0.6% by weight. If the amount is more than 1.0% by weight, poor appearance or the like is likely to occur.

When a soft amorphous α-olefin polymer, which is incompatible with the matrix amorphous resin composition, is present in the vicinity of the very surface layer of the molded article during the injection molding, the fine surface dispersion of the molded article is prevented. The elastic modulus in the vicinity decreases. By this, it is assumed that the interface of the molded product 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 taken into the non-crystalline α-olefin copolymer and exerts an effect of reducing friction between the surface of the molded article and the mold at the time of release.

The resin composition of the present invention comprises (A) an amorphous α
By using the olefin copolymer and (B) a fatty acid metal salt together, a synergistic effect of micro-deformation of the very surface of the molded product in contact with the mold during mold release and reduction of friction between the mold and the molded product is exhibited. Therefore, the releasability is dramatically improved.

The mixing of the resin composition constituting the present invention is achieved by a conventionally known technique such as dry blending, an extruder, a heating roll, a Banbury mixer, a kneader and the like, and these can be used in combination, but are particularly preferable. What is mixing by an extruder. Further, other additives such as a plasticizer, a stabilizer, an antistatic agent, an ultraviolet absorber, a flame retardant, a colorant, a release agent, and the like, to the extent that the invention is not impaired, may be included in the resin composition constituting the present invention. Fibrous reinforcing agents such as glass fibers, potassium titanate whiskers, and zinc oxide whiskers, as well as glass beads, glass flakes, mica,
Fillers such as calcium carbonate and talc can be added. Stabilizers include phosphites, hindered phenols, alkanolamines, acid amides,
It can be used alone or in combination from metal dithiocarbamates, inorganic sulfides and metal oxides.

The resin composition of the present invention and a molded product thereof are
The releasability, which is a disadvantage of the non-crystalline resin, has been improved, and it can be mainly used for applications requiring releasability, for example, applications that are likely to cause mold release failure due to components having complicated shapes. In particular, switchboard parts, deflection yokes, flyback transformers, connectors, battery cases, adapter cases,
It is suitable for application to electric and electronic field components such as chassis, and to automobile field components such as meter hoods, center clusters, and ignition coil bobbins.

Hereinafter, the present invention will be described based on embodiments. Modified PPE resin and PC resin are mentioned as typical examples, but the present invention is not limited to modified PPE and PC resin. The components used in the 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 mold releasability and presence / absence of a molded article surface appearance defect. Was carried out.

1) Polyphenylene ether resin Poly (2,6-dimethyl-1,4-phenylene) ether having an intrinsic viscosity of 0.50 (30 ° C. in chloroform) (density: 1.06 g / cm ³ ) 2) Polystyrene Resin Reduced viscosity ηsp / c is 0.92 dl / g (at 30 ° C. in toluene), (density 0.5 g / cm ³ )

3) Rubber-reinforced polystyrene resin Polybutadiene rubber Modified polystyrene having an average particle diameter of 0.7 μm 4) Polycarbonate resin Panlite L-12255 manufactured by Teijin Chemicals Ltd. 5) Ethylene-propylene copolymer Mitsui Chemicals, Inc. Tuffmer P0680J 6) Magnesium stearate Dainichi Chemical Industry Co., Ltd.

The method for evaluating the releasability and the surface appearance of the molded product is as follows. (1) Releasability Injection molding of a cup-shaped molded product having an outer diameter of 50 mm, a height of 50 mm, and a wall thickness of 3 mm was performed, and a load required for projecting the molded product was measured as a release force. (2) Appearance of Molded Article The resin surface of the molded article was visually inspected for the presence or absence of clouding or gas burning on the surface of the molded article.

[0019]

Examples 1 to 4 A modified PPE resin composition containing a polyphenylene ether resin and a polystyrene resin / rubber reinforced polystyrene resin as main components and a polycarbonate resin containing an amorphous α-olefin copolymer (ethylene-propylene block copolymer) The resin composition shown in Table 1 mixed with a fatty acid metal salt (magnesium stearate) was injection molded to evaluate the releasability and the presence or absence of resin surface peeling. Table 1 shows the evaluation results.

[0020]

Comparative Examples 1 to 6 Comparative Examples 1 and 2 show the releasability when the same resin composition as in Examples 1 and 4 was used without any additives. Also, Comparative Examples 3, 4, and 5 show the releasability when the amorphous α-olefin copolymer and the fatty acid metal salt were not used in combination. 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 they are blended singly without combined use, the release force of the examples is significantly reduced, It can be seen that it shows good releasability.

In particular, when the fatty acid metal salt alone of Comparative Example 5 was blended in a large amount, the releasing force was increased as compared with the case where the amorphous α-olefin copolymer and the fatty acid metal salt were blended together. Not only that, the molded article was found to be cloudy or a little poor gas burning. The result in the case of adding more than 2.0% of the amorphous α-olefin copolymer and more than 1.0% of the fatty acid metal salt to Comparative Example 6 is shown. Although the releasability is good, it is considered to be due to exfoliation of the resin surface of the molded article, which is considered to be caused by blending a large amount of the amorphous α-olefin copolymer, and to blending a large amount of fatty acid metal salt. Fogging of the molded article and slight gas burning failure were observed.

[0022]

[Table 1]

[0023]

As described above, the resin composition of the present invention is excellent in mold releasability, so that it can cope with a complicated shape of an injection molded product, and the freedom of shape design is expanded. By using a specific amorphous α-olefin copolymer and a fatty acid metal salt in combination as a release agent, a synergistic effect is produced, the amount of addition can be reduced, and stable and excellent release properties can be maintained. It sufficiently meets the market needs for improving the releasability of the resin for injection molding in terms of price and performance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C08L 71/12 C08L 71/12 F term (Reference) 4F071 AA12X AA15 AA15X AA20X AA21X AA22 AA22X AA34X AA50 AA51 AA62 AA64 AA77 AC09 BA01 BB05 BC07 4J002 BB153 BC03X BC05X BC06X BN15X CG00X CH07W CM04X CN01X CN03X EG036 FD166

Claims (6)

[Claims] 1. A composition comprising a resin composition containing a non-crystalline resin as a main component and (A) a non-crystalline α-olefin copolymer and (B) a fatty acid metal salt in combination. ) And (B) in a total amount of 0.3 to 3.0% by weight. 2. The thermoplastic resin composition according to claim 1, wherein the non-crystalline resin is a polyphenylene ether-based resin or a resin composition containing a polyphenylene ether-based resin and a styrene-based resin as main components. 3. The thermoplastic resin composition according to claim 1, wherein (A) the amorphous α-olefin copolymer is an ethylene-propylene copolymer. 4. The thermoplastic resin composition according to claim 1, wherein (B) the metal salt of a fatty acid is a metal salt of stearic acid. 5. The thermoplastic resin composition according to claim 1, wherein the fatty acid metal salt (B) is magnesium stearate. 6. A molded article produced by injection molding the thermoplastic resin composition according to claim 1.