JPH04239566A - Resin composition - Google Patents

Abstract

PURPOSE:To provide a resin composition providing molded articles having excellent fluidity, mold release characteristics and low molding shrinkage, comprising an engineering plastics and a specific liquid ethylene.alpha-olefin random copolymer. CONSTITUTION:(A) 100 pts.wt. engineering plastics such as polyacetal resin, polyamide resin or modified polyphenylene oxide resin is blended in a molten state with (B) 0.1-10 pts.wt., preferably 0.2-8 pts.wt., more preferably 0.5-6 pts.wt. liquid random copolymer of ethylene and 3-20C alpha-olefin (preferably propylene) having 500-10,000, preferably 600-8,000, more preferably 700-5,000 number-average molecular weight and 20-80mol%, preferably 30-70mol%, more preferably 40-60mol% ethylene content, such as one obtained by randomly copolymerizing ethylene with 3-20C alpha-olefin in the presence of Ziegler catalyst by using hydrogen as a molecular weight modifier.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD OF THE INVENTION The present invention relates to a resin composition, and more particularly, the present invention relates to a resin composition that has excellent molding processability, particularly fluidity, and mold releasability, and is free from defects in the appearance of molded products and stains caused by resin, etc. in molds. The present invention relates to a resin composition that can provide engineering plastic molded products with low molding shrinkage.

0002

[Technical Background of the Invention] Engineering plastics such as polyacetal, polyamide, polycarbonate, modified polyphenylene oxide, polyimide, and polyester have high melting points and excellent mechanical properties, so they are used in various fields such as the automobile industry and electrical industry. Widely used in industrial fields. However, among engineering plastics, there are many resins that have poor mold releasability from the molds used during molding, and these resins are especially used to manufacture thin-walled molded products or molded products with complex shapes. However, there were problems in that the molded product was easily damaged when taken out and also caused poor appearance.

Furthermore, some engineering plastics have low fluidity and cannot be smoothly fed into a molding machine from the hopper of a molding machine used during injection molding or extrusion molding. Therefore, such resin compositions have problems such as the measurement accuracy tends to become unstable, and the quality of various molded products obtained by molding methods such as injection molding tends to become unstable. .

[0004] Conventionally, in order to solve the above-mentioned problems, methods have been adopted in which various types of mold release agents and lubricants are added to resins. Conventionally used mold release agents or lubricants include stearic acid metal salts, inorganic substances such as talc, soybean lecithin, natural waxes, and synthetic waxes. However, it has been difficult to prevent defects such as poor appearance of the molded product and staining of the mold.

[0005]

OBJECTS OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above.
To provide a resin composition that provides an engineering plastic molded product with particularly excellent fluidity and mold releasability, a low mold shrinkage rate, and no defective appearance of the molded product or staining of the mold with resin, etc. It is an object.

[0006]

Summary of the Invention The resin composition according to the present invention comprises one type selected from the group consisting of polyacetal resins, polyamide resins, modified polyphenylene oxide resins, polyimide resins, polyester resins, epoxy resins, unsaturated polyester resins, and phenolic resins. 100 parts by weight of the resin (A), the number average molecular weight is within the range of 500 to 10,000, and the ethylene content is within the range of 20 to 80 mol%,
and a liquid ethylene/α-olefin random copolymer (B) in which the α-olefin has 3 to 20 carbon atoms.
)0.1 to 10 parts by weight.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The resin composition according to the present invention will be specifically explained below. The resin composition according to the present invention is
It is composed of a specific resin (A) and a specific liquid ethylene/α-olefin random copolymer (B).

[0008] The resin (A) used in the present invention is as follows:
Examples include thermoplastic resins such as polyacetal resin, polyamide resin, modified polyphenylene oxide resin, polyimide resin, and polyester resin, and thermosetting resins such as epoxy resin, unsaturated polyester resin, polyimide resin, and phenol resin.

These resins are described in publications such as "Engineering Plastics" (edited by Makihiro and Rikio Kobayashi, published by Sangyo Tosho Co., Ltd.) and "FRP Design Handbook" (published by the Reinforced Plastics Technology Association). It can be manufactured by a known method such as that described above.

Liquid ethylene α- used in the present invention
The olefin random copolymer (B) is a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Specifically, the above α-olefin having 3 to 20 carbon atoms includes propylene, butene-1
, pentene-1, 4-methylpentene-1, hexene-
1, heptene-1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1
, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1 or eicosene-1. Among these, propylene is most preferable in terms of productivity and the like.

Liquid ethylene α- used in the present invention
The ethylene content of the olefin random copolymer (B) is
The content is in the range of 20 to 80 mol%, preferably 30 to 70 mol%, and more preferably 40 to 60 mol%. Liquid ethylene α- with an ethylene content within the above range
Since the olefin random copolymer has good thermal stability, it does not lose weight during the kneading operation with the resin (A) as described above, and it also carbonizes during molding and contaminates the molded product. Not at all.

Liquid ethylene α- used in the present invention
The number average molecular weight (value determined by vapor pressure osmometer) of the olefin random copolymer (B) is 500 to 10,000, preferably 600 to 10,000.
8,000, more preferably within the range of 700 to 5,000. A liquid ethylene/α-olefin random copolymer with a number average molecular weight within the above range has good thermal stability and does not evaporate when heated, so it can be used with resin (A) as described above. There is no loss of weight during mixing, and the mixing operation with the resin (A) is easy.

The liquid ethylene/α-olefin random copolymer (B) as described above is disclosed in Japanese Patent Publication No. 2-1, for example.
It can be produced by the method described in Japanese Patent No. 163. That is, in the presence of a Ziegler catalyst, hydrogen is used as a molecular weight regulator, and ethylene and
A liquid ethylene/α-olefin random copolymer can be obtained by random copolymerization with α-olefin No. 20.

In the present invention, liquid ethylene α-
The olefin random copolymer (B) is made from the above resin (A
) It is used in a ratio of 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, and more preferably 0.5 to 6 parts by weight, per 100 parts by weight.

[0015] A resin composition in which the liquid ethylene/α-olefin random copolymer (B) is blended with the resin (A) in the above ratio has excellent moldability, especially fluidity and mold release. It is possible to provide an engineering plastic molded product that has excellent moldability, can prevent poor appearance of the molded product and staining of the mold with resin, and has a low molding shrinkage rate.

In the present invention, resin (A) and liquid ethylene
The method of mixing with the α-olefin random copolymer (B) is not particularly limited, and any conventionally known mixing method can be employed.

Methods for molding the resin composition according to the present invention obtained as described above include extrusion molding method, injection molding method, vacuum molding method, blow molding method, compression molding method,
A widely used molding method such as a transfer molding method can be employed.

The resin composition according to the present invention contains additives such as heat stabilizers, weather stabilizers, flame retardants, antistatic agents, nucleating agents, colorants, blowing agents, fillers, and reinforcing agents. It can be blended within the range that does not impair the purpose.

[0019]

Effects of the Invention The resin composition according to the present invention is composed of a specific resin (A) and a specific liquid ethylene/α-olefin random copolymer (B) blended in a specific ratio, so that it is easy to mold and process. It is possible to provide engineering plastic molded products that have excellent properties, particularly fluidity and mold release properties, can prevent poor appearance of molded products and dirt from mold resin, and have low mold shrinkage. can.

[0020] The present invention will be explained below with reference to Examples.
The present invention is not limited to these examples.

[0021]

[Example 1] Polyacetal resin [Mitsubishi Gas Chemical Co., Ltd.]
manufactured by Iupital F20-01] 100 parts by weight, ethylene content 52 mol%, number average molecular weight 2.20 as determined by vapor pressure osmometer.
0 and 2 parts by weight of a liquid ethylene/propylene random copolymer were melt-mixed using a vented extruder and pelletized. The obtained pellets were molded using an injection molding machine [Model IS-50EP manufactured by Toshiba Machinery Co., Ltd.], and the mold releasability and mold staining property of the obtained molded product were evaluated by the following methods. <Evaluation method> Mold releasability External dimensions 80cm x 50cm x 50cm, thickness 0.8m
Injection molding is carried out using a square box mold of size m, and if the obtained molded product has no deformation and can be released well, the rating is 〇, and if there is partial deformation, the rating is △. If the overall deformation was severe, it was rated as ×. Mold staining property: Injection molded using the same square box mold as above, if the molded product was molded without stains, it is ○, if it is partially dirty, it is △, the whole is dirty. × if it was severe
It was evaluated as follows.

The above evaluation results are shown in Table 1.

[0023]

[Examples 2 to 5] In Example 1, polyamide resin [manufactured by Ube Industries, Ltd., trade name: UBE Nylon 1013B] and modified polyphenylene oxide resin [manufactured by Asahi Kasei Industries, Ltd., trade name] were used instead of polyacetal resin, respectively. Zylon 500V], thermoplastic polyimide resin [manufactured by General Electric Company, trade name Ultem 1000]
, injection molding was carried out in the same manner as in Example 1 except that polyester resin [manufactured by Polyplastics Co., Ltd., trade name DURANEX 3310; PBT] was used, and the mold releasability and Mold stain resistance was evaluated.

[0024] The evaluation results are shown in Table 1.

[0025]

[Comparative Examples 1 to 5] In Examples 1 to 5, except that the liquid ethylene/propylene random copolymer was not used,
Injection molding was performed in the same manner as in Examples 1 to 5, and the mold releasability and mold staining property of the obtained molded products were evaluated.

Table 1 shows the evaluation results.

[0027]

[Example 6]
100 parts by weight of epoxy resin [manufactured by Mitsui Petrochemical Industries, Ltd., trade name: Epomic TMR-140; diaminodiphenylmethane epoxy resin],
150 parts by weight of silica as a filler and an ethylene content of 4
4 parts by weight of a liquid ethylene-propylene random copolymer having a number average molecular weight of 1,200 as determined by a vapor pressure osmometer and 9 mol% were kneaded using a roll, and then kneaded using a compression molding machine [Kawasaki Yuko Co., Ltd. ) made,
100 ton press], and the mold releasability and molding shrinkage rate of the obtained molded product were evaluated by the following methods. <Evaluation method> Mold releasability If compression molding is performed using a flat plate molding die of 200 cm x 200 cm x 4 mm, and the obtained molded product has no deformation and can be successfully released from the mold, 〇, If there was partial deformation, it was evaluated as △, and if the entire deformation was severe, it was evaluated as ×. Molding Shrinkage Rate The molding shrinkage rate of the flat plate obtained by compression molding using the same flat plate molding die was determined according to JIS K6911.

The above evaluation results are shown in Table 2.

[0029]

[Examples 7 to 9] In Example 6, in place of the epoxy resin, unsaturated polyester resin [manufactured by Showa Kobunshi Co., Ltd., trade name Rigorac 158BQT; main catalyst component methyl ethyl ketone peroxide (MEKP)],
Except for using phenol resin [manufactured by Showa Kobunshi Co., Ltd., trade name: SHONOL BRL-240/FRH-30 series] and thermosetting polyimide resin [manufactured by Nippon Polyimide Co., Ltd., trade name: Kelimide K-601]. The molded product was compression molded in the same manner as in Example 6, and the mold releasability and molding shrinkage rate of the obtained molded product were evaluated.

Table 2 shows the evaluation results.

[0031]

[Comparative Examples 6 to 9] In Examples 6 to 9, except that the liquid ethylene/propylene random copolymer was not used,
Compression molding was performed in the same manner as in Examples 6 to 9, respectively, and the mold releasability and molding shrinkage rate of the obtained molded products were evaluated.

Table 2 shows the evaluation results.

Claims (1)

[Claims] [Claim 1] Polyacetal resin, polyamide resin, modified polyphenylene oxide resin, polyimide resin,
1 selected from the group consisting of polyester resin, epoxy resin, unsaturated polyester resin and phenolic resin
100 parts by weight of seed resin (A) and a number average molecular weight of 500
~10,000, and the ethylene content is from 20 to
80 mol%, and 0.1 to 10 parts by weight of a liquid ethylene/α-olefin random copolymer (B) in which the α-olefin has 3 to 20 carbon atoms. A resin composition.