KR930004288B1 - Thermoplastic resin composition - Google Patents

Abstract

The resin composition comprises (A) 40-90 wt.pts. of polyamide resin, (B) 5-30 wt.pts. of core-shell type copolymer composed of 20-90 wt.% acrylic rubber or diene rubber and 80-10 wt.% unsaturated compound grafted onto the rubber component, and (C) 0.5-30 wt.pts. of carboxy terminated polycaprolactone. The polyamide resin is at least one copolymer or blend composed of nylon 6, nylon 66, nylon 11 and/or nylon 12. The core-shell copolymer is obtained by copolymerizing at least one core component selected from acrylic acid ethyl ester, acrylic acid butyl ester, butadiene or isoprene, and at least one shell component selected from styrene, alpha-methyl styrene, acrylonitrile or butyl methacrylate. The resin composition has a good mechanical strength and precessability.

Description

Thermoplastic resin composition

The present invention relates to a thermoplastic resin composition having excellent mechanical strength, excellent workability and beautiful appearance, and excellent impact resistance at room temperature as well as low temperature. More specifically, the present invention relates to a polyamide resin and a core-shell type copolymer and a carbon. It relates to a thermoplastic resin composition composed of a polarcaprolactone copolymer in which an acid is substituted at the terminal.

In general, polyamide resin has been a major factor in engineering plastics due to its excellent wear resistance, mechanical properties and chemical resistance. However, since it has a very low impact strength below the secondary transition temperature (hereinafter referred to as Tg), many applications have been limited to applications requiring impact resistance.

In order to compensate for these disadvantages, a method of "water treatment" of the molded article is used, but the process is cumbersome and difficult to increase the impact resistance to a certain degree or more.

Therefore, in recent years, researches to improve the impact resistance of polyamide resins by copolymerizing or blending impact modifiers have been widely conducted. Most of the impact modifiers are elastomers: styrene-butadiene elastomers (SBR), acrylonitrile-butadiene elastomers (NBR), acrylonitrile-butadiene-styrene copolymers (ABS), ethylene-propylene-diene elastomers (EPR) , Ethylene-propylene-diene elastomer (EPDM), ethylene-vinylacetate elastomer (EVA), polyaminoprene elastomer, methyl methacrylate-butadiene-styrene copolymer (MBS) and the like have been mainly used.

However, the above-mentioned impact modifiers are difficult to improve the impact resistance of the resin composition by causing phase separation due to low compatibility with the polyamide resin.

Extremely compatible mixtures do not separate into their respective phases to form a homogeneous composition, but low-compatible mixtures separate into their respective phases or weakly bind to each other It is easy to crack even in impact, so high impact strength cannot be obtained.

As a method of preventing such phase separation, a crosslinking method may be introduced by introducing a peroxide compound in two minutes or crosslinking using heat, or crosslinking using a radiation technology, or a rubber core ( It is known to increase the impact resistance of polyamide resin by grafting a monomer containing a carboxyl group capable of reacting with an amide gear on the core. Also, in the specification of US Pat. No. 4,1879, polybutadiene is grafting substrate. The impact strength is increased by using acrylate, methacrylate, acryltonitrile or acrylamide as a shell.

In addition, in the case of EPDM and EPR, the impact strength cannot be increased due to incompatibility with nylon resin, and after grafting monomers such as maleic anhydride or acid, an amide group and a gold oil bond are formed to improve impact resistance, Intensive shear force is required to uniformly disperse the above-mentioned rubber or elastic polyamide resin. However, the above method has a drastic increase in molecular weight in the final composition, thereby significantly lowering the fluidity, which adversely affects the processability and the appearance is not beautiful, as well as difficulty in reinforcement with glass fiber or inorganic filler.

In order to solve the above problems, the present inventors have copolymerized polypropylene and polyamide resins in which two or more different monomers are grafted to a core structure of an acrylic rubber or butadiene rubber, and a polycaprolactone substituted at the carboxyl end. As a result of blending gruop termina polycaprolactone, the impact strength was improved as well as high fluidity, resulting in a composition with improved processability.

That is, the present invention is a core-shell form comprising (A) 40-90 parts by weight of polyamide resin, (B) 20-90% by weight of acrylic rubber or diene rubber, and 80-10% by weight of unsaturated compound graftable to rubber components. The resin composition which consists of 50-30 weight part of copolymers and 0.5-30 weight part of (C) terminal carboxyl polycaprolactone.

Hereinafter, the present invention will be described in detail. In the present invention, the polyamide resin (A) is a linear crystalline polymer having a common amide group, for example, nylon 6, nylon 66, nylon 11, nylon 12 and copolymers or blends thereof. Or nylon 66 and blends thereof.

In addition, the component (B) used in the present invention is a core-shell copolymer, prepared by a conventional emulsion polymerization method, and each component is as follows. The rubber component constituting the core component is acrylic, such as acrylic acid ethyl ester, acrylic acid butyl ester, acrylic acid propyl ester, acrylic acid-2-ethylhexyl ester, and the diene type includes butadiene, isoprene, chloroprene and cyanobutadiene. It can be used, and the preferred amount to improve the impact resistance is 40 to 80 parts by weight based on the total (B) component.

In addition, unsaturated compounds that can be grafted to rubber, which is a core component forming a shell, include styrene, methyl styrene, halostyrene, P-ethyl styrene, acrylonitrile, methyl methacrylate, N-phenylmaleimide, methacrylonitrile, Butyl methacrylonitrile, butyl methacrylate, and the like are used, and it is preferable to use two or more kinds of the monomers to form a copolymer.

The polycaprolactone substituted with the carboxyl group used as the component (C) of the present invention is a polymerized caprolactone having a five-membered (5 Menbered) structure, which is converted into a carboxylic acid by water treatment of ester groups at both ends. will be.

The molecular weight that can be used in the present invention can be used up to 10, 000-300, 000. In this experiment, nylon 6, MBS, and water-treated polycaprolactone (molecular weight: 30,000) were used.

An amide bond is formed between the nylon 6 and the polycaprolactone in the carboxyl period in which the amine group of the nylon 6 terminal is substituted at the polycaprolactone terminal. It is also known that there is compatibility between MBS and polycaprolactone grafted with a large amount of methyl methacrylate.

Therefore, polycaprolactone evenly distributes the MBS elastomer on the nylon resin and greatly improves the impact resistance. Also, the polycaprolactone does not significantly affect the melt flow due to the MBS rubber phase and phase separation at the processing temperature. It shows workability.

The preparation of the polyamide resin composition of the present invention is obtained by basic melt mixing such as Banburmixing Kneader, twin screw, milling or exteusion, As a result, pigments, dyes, release agents, heat stabilizers, antioxidants, lubricants, and the like may be added, and glass fibers or inorganic fillers may be reinforced to obtain excellent mechanical strength.

When described in detail by the following examples.

Example 1

80 g of nylon 6, 20 g of MBS and 0.5 g of substituted polycaprolactone were trained for 20 seconds at a barrel temperature of 240-265 ° C. on a twin screw, and the die temperature was adjusted to 240 ° C. After passing through the cooling water was pelletized (Pelletizing).

All compositions made of pellets were fabricated into specimens conforming to ASTM standards at a temperature of 250 ° C. through an injection machine, and the impact strength and melt index were measured and the results are shown in Table III.

Example 2

Except that 80g nylon 6 and 20g MBS 2g substituted polycaprolactone resin was used to prepare a specimen in the same manner as in Example 1 and measured the physical properties and the results are shown in Table III.

Example 3

Except for using 80g nylon 6 and 20g MBS 5g substituted polycaprolacto was prepared in the same manner as in Example 1 and then the physical properties were measured and the results are shown in Table III.

Example 4-8

Except for using nylon 6, MBS, and substituted polycaprolactone as shown in Table I, the specimens were prepared in the same manner as in Example 1, and their physical properties were measured. The results are shown in Table III.

TABLE I

Comparative Example 1

Except that 80 g of nylon 6 and 20 g of MBS were used to prepare the specimens in the same manner as in Example 1, the physical properties thereof were measured, and the results are shown in Table III.

Comparative Example 2-4

Except MBS and nylon 6 or nylon and substituted polycaprolactone MBS and polycaprolactone resins were prepared in the same manner as in Example 1 except that the specimens were prepared and the physical properties thereof were measured and the results are shown in Table III. It was.

TABLE II

As described above, the embodiment having the composition of the present invention has not only improved impact strength as compared with the comparative example, but also has high fluidity and significantly increased workability.

Claims (4)

(A) 40-90 parts by weight of polyamide resin, (B) 20-90% by weight of acrylic rubber or diene rubber and 80-10% by weight of unsaturated compound grafted to rubber component -30 parts by weight (C) A thermoplastic resin composition composed of 0.5-30 parts by weight of polycaprolactone in which a carboxyl group is substituted at the end. The thermoplastic resin composition according to claim 1, wherein the polyamide resin is at least one selected from nylon 6, nylon 66, nylon 11, nylon 12, copolymers or blends thereof. The core-shell copolymer of claim 1, wherein the core component is at least one selected from acrylic acid ethyl ester, acrylic acid butyl ester, acrylic acid propyl ester, acrylic acid-2, ethyl hexyl ester, butadiene, isoprene, chloroprene and cyanobutadiene. And the shell component copolymerize at least one selected from styrene, α-methylstyrene, halostyrene, P-methylstyrene, acrylonitrile, methyl methacrylate, N-phenylmaleimide, methacrylonitrile and butyl methacrylate. Thermoplastic resin composition characterized in that the copolymer produced. The thermoplastic resin composition of claim 1, wherein the polycaprolactone substituted with a carboxyl group has a molecular weight of 10, 000-300, 000.