KR19980031234A - Thermoplastic resin composition with excellent impact strength - Google Patents

Abstract

The present invention (A) 10 to 90 parts by weight of a polyamide resin; (B) Vinyl-based graft copolymer 10 to 40 to 90 parts by weight of the rubbery polymer obtained by graft polymerization of 40 to 90 parts by weight of an aromatic vinyl monomer and 75 to 30 parts by weight of a monomer mixture of 60 to 10 parts by weight of a vinyl cyanide monomer. 90 parts by weight; (C) 40 to 90 parts by weight of an aromatic vinyl monomer, 0 to 20 parts by weight of a vinyl copolymer obtained by copolymerizing 60 to 10 parts by weight of a vinyl cyanide monomer and 0 to 40 parts by weight of other vinyl monomers copolymerizable with these; (D) Unsaturated carboxylic acid or in the state in which 0-2 weight part of organic peroxides were added with respect to 100 weight part of graft copolymers which graft-polymerized 20-99 weight part of aromatic vinylic monomers to 1-80 weight part of rubbery polymers. 1 to 50 parts by weight of a modified vinyl aromatic graft copolymer obtained by melt kneading and kneading a reactive monomer having an anhydride group in an amount of 0.01 to 10 parts by weight; And (E) 30 to 70 mol% of aromatic vinyl monomers, 30 to 50 mol% of maleimide monomers, 1 to 20 mol% of unsaturated carboxylic acids or reactive monomers having anhydride groups, and 0 to 35 mol% of other copolymerizable monomers. To provide a thermoplastic resin composition excellent in impact strength, characterized in that it is prepared by blending, melt-kneading 1 to 30 parts by weight of the maleimide-based copolymer, the thermoplastic resin composition of the present invention is excellent in chemical resistance, moldability and heat resistance Of course, it is possible to develop a wide range of applications as an engineering plastic because of its excellent impact resistance, particularly at low temperatures.

Description

Thermoplastic Occasional Composition with Excellent Impact Strength

The present invention relates to a thermoplastic resin composition having excellent impact strength, and more particularly to a low temperature containing a polyamide resin, a vinyl copolymer resin, and a modified vinyl aromatic graft copolymer and a maleimide copolymer. The present invention relates to a thermoplastic resin composition having excellent impact resistance.

In general, polyamide resins are widely used in industrial fields such as automobile parts, electrical parts, and electronic parts because of their excellent chemical resistance and moldability, but they have a disadvantage of low heat resistance and impact resistance, particularly notched impact strength. Its use is limited. Recently, researches on resin compositions having improved impact strength by adding thermoplastic elastomers to polyamides have been actively conducted. Known techniques are disclosed in US Pat. Nos. 4,321,336 and 4,299,977.

On the other hand, the vinyl aromatic copolymer, which is a general-purpose resin, has some drawbacks of poor moldability and chemical resistance and poor heat resistance, and its use as an engineering plastic is limited. Therefore, the development of a new polymer alloy to compensate for the disadvantages of these two resins has been actively developed. It's going on.

However, simply blending the vinyl aromatic copolymer and the polyamide resin causes a phase separation phenomenon in the composition because there is no compatibility between the two resins, and a peeling phenomenon of the molded article occurs, which makes it difficult to use industrially. The general method to increase the compatibility of the polymer alloy used to solve this problem is to add a compatibilizer, the compatibilizer used is highly reactive with the unreacted compatibilizer depending on the presence or absence of reactivity with the polymer composition It is replaced with a compatibilizer.

The method of improving the compatibility of the vinyl aromatic copolymer and the polyamide resin alloy by using an unreactive compatibilizer is to synthesize and add the components compatible with the two polymer components in the alloy composition as a block or graft copolymer. As a method, U.S. Patent No. 4,496,690, which is known as a representative technique for this method, uses a resin obtained by graft polymerization of a monomer such as acrylamide in a styrene-based copolymer to improve compatibility between vinyl aromatic copolymer and polyamide resin. A method is disclosed. Since the unreacted compatibilizer does not react with the polymer in the composition, it does not damage the original polymer chain and thus has the advantage of preventing physical property deterioration due to the decrease in the molecular weight of the composition, but in order to increase the compatibility to an appropriate level The disadvantage is that a large amount of compatibilizer must be used.

On the other hand, the method of using a reactive compatibilizer is a technology that can improve the compatibility of incompatible polymer alloys, and is an active research field. It is mainly used to graft copolymerize a reactant that can react with a specific polymer in a polymer chain. It is a method of increasing the compatibility between two or more polymer materials by forming a graft or block copolymer through the reaction.

Although this method has a good compatibility improvement effect even when a small amount is used, there is a disadvantage that the mechanical properties of the final alloy is significantly lowered when used below or above an appropriate level.

Modified polystyrene or modified polyolefin copolymer obtained by grafting unsaturated carboxylic acid or anhydride to Japanese Patent Application Laid-Open No. 54-54166, 58-120663, 63-179957, and Japanese Patent Laid-Open No. 2-240158, etc. And a method of blending polyamide with polyamide, and Japanese Patent Application Laid-Open No. Hei 2-22356 improves its thermal stability and other mechanical properties, and adds polyglutimid resin to a styrene copolymer to improve heat resistance. Technology is presented. However, such resin compositions, although the impact strength at room temperature exhibits a certain level or more, at low temperatures, the impact resistance is sharply lowered.

In addition, a technique of adding an olefin rubber such as modified EPR and EPDM copolymerized with a maleimide resin and an unsaturated carboxylic acid to a mixture of a polyamide resin, a thermoplastic resin such as a polycarbonate and a styrene crab copolymer is disclosed. Although disclosed in US Pat. No. 3,115,45, this technique has a weakness that the impact reinforcing effect is not great at low temperatures as well as at room temperature.

Accordingly, the present inventors have diligently studied to overcome the problems of the prior art as described above. When the polyamide resin, vinyl copolymer, modified vinyl aromatic graft copolymer, and maleimide copolymer are used at an appropriate ratio, In addition, it has been found that a resin having excellent impact resistance can be produced, particularly at low temperatures, and thus the present invention has been completed.

An object of the present invention is a resin composition composed of a polyamide resin and a vinyl copolymer and composed of a modified vinyl aromatic graft copolymer and a maleimide copolymer, and is compatible with a polyamide resin and a vinyl graft copolymer. It is to provide a thermoplastic resin composition with improved properties.

Another object of the present invention is to provide a thermoplastic resin composition excellent in impact resistance, particularly at low temperature.

Still another object of the present invention is to provide a thermoplastic resin composition having excellent chemical resistance, moldability and heat resistance.

That is, this invention (A). 10 to 90 parts by weight of polyamide resin; (B). 10 to 90 parts by weight of a vinyl graft copolymer obtained by graft polymerization of 25 to 70 parts by weight of the rubber polymer 40 to 90 parts by weight of an aromatic vinyl monomer and 60 to 10 parts by weight of a vinyl cyanide monomer 30 parts by weight in a monomer mixture 75 ; (C). 0 to 20 parts by weight of the vinyl copolymer obtained by copolymerizing 90 parts by weight of the aromatic vinyl monomer 40 and 60 to 10 parts by weight of the vinyl cyanide monomer and 0 to 40 parts by weight of other vinyl monomers copolymerizable with these; (D). Unsaturated carboxylic acid or anhydride group thereof is added to 0 to 2 parts by weight of an organic peroxide based on 100 parts by weight of a graft copolymer obtained by graft copolymerization of 20 to 99 parts by weight of an aromatic vinyl monomer to 1 to 80 parts by weight of a rubbery polymer. 1 to 50 parts by weight of a modified vinyl aromatic graft copolymer obtained by melt kneading and carrying out graft reaction of 0.01 to 10 parts by weight of a reactive monomer having; And (E). Maleimide air of 30 to 70 mol% of aromatic vinyl monomers, 30 to 50 mol% of maleimide monomers, 1 to 20 mol% of unsaturated carboxylic acids or reactive monomers having anhydride groups, and 0 to 35 mol% of other copolymerizable monomers It is to provide a thermoplastic resin composition excellent in impact strength, characterized in that the composition is composed of 1 to 30 parts by weight of coalescing.

(A) polyamide resin, (B) vinyl graft copolymer, (C) vinyl copolymer, (D) modified vinyl aromatic graft copolymer which is each component of the thermoplastic resin composition of this invention, and ( E) A maleimide copolymer is explained in full detail.

(A) polyamide resin

The polyamide resin, which is the component (A) used in the present invention, is polycaprolactam (nylon 6), poly (11-aminoundecanoic acid) (nylon 11), polylauryllactam (nylon 12), poly hexamethylene Adipamide (nylon 6, 6), polyhexaethylene azelamide (nylon 6, 9), poly hexamethylene sebacamide (nylon 6, 10), polyhexamethylene dodecanodiamide (nylon 6, 12) and the like Nylons such as nylon 6/6, 10, nylon 6/6, 6, nylon 6/12, etc., which may be used alone or in combination of two or more thereof in an appropriate ratio.

However, considering the mechanical properties and heat resistance of the resin composition, it is preferable to select a polyamide resin having a melting point of 200 ° C. or higher and a relative viscosity (measured at 25 ° C. by adding 1 wt% of polyamide resin to m = cresol) good.

(B) Vinyl Graft Copolymer

The vinyl graft copolymer as the component (B) used in the present invention is a monomer mixture 75 to 30 parts by weight of the vinyl polymer 25 to 70 parts by weight of an aromatic vinyl monomer and 60 to 10 parts by weight of a vinyl cyanide monomer. It is a copolymer grafted by weight part.

As the rubbery polymer in the present invention, one or more rubbers selected from the group consisting of diene rubbers, ethylene rubbers and ternary copolymer rubbers of ethylene / propylene / diene monomers may be used, and the average particle diameter of rubber particles of rubbery polymers may be used. Silver may be used 0.1 ~ 1.0μ, preferably 0.2 ~ 0.5μ. If the average particle diameter of the rubber particles is less than 0.1μ, it is difficult to prepare a graft copolymer, and if it exceeds 1.0μ, the effect of low temperature impact strength is always insufficient.

In the present invention, the aromatic vinyl monomer of the vinyl graft copolymer is styrene, p, t-butyl styrene, alpha-methylstyrene, beta-methyl styrene, vinyl xylene, monochlorostyrene, dichlorostyrene, dibromostyrene , Aromatic vinyl monomers such as chlorostyrene, ethyl styrene, vinyl naphthalene, divinylbenzene, and vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like, may be used. It is preferable to use styrene, acrylonitrile or the like.

In the present invention, the content of the rubbery polymer used to prepare the vinyl graft copolymer (B) is preferably 25 to 70 parts by weight based on 100 parts by weight of the sum of the components (B) and (C), more preferably 35 To 60 parts by weight is good. When the amount of the rubbery polymer is less than 25 parts by weight, the hardness, tensile strength, flexural strength and heat resistance of the thermoplastic resin composition are improved, but the impact resistance is drastically reduced. Since the problem of falling strength occurs, it is essential that the content of the rubbery polymer in the present invention is within the above range.

In the present invention, a method of graft copolymerizing an aromatic vinyl monomer, a rubbery polymer, and a vinyl cyanide monomer to obtain a vinyl graft copolymer is a method well known to those skilled in the art. Either emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization can be used. Among these, a preferable production method is a method of emulsion polymerization or bulk polymerization as a polymerization initiator by adding the above-described vinyl monomer in the presence of a rubbery polymer.

(C) vinyl copolymer

As the aromatic and vinyl cyanide monomers used in the preparation of the copolymer of the vinyl copolymer, which is the component (C) of the present invention, the monomers used in the preparation of the vinyl graft copolymer (B) may be used. Other vinyl monomers copolymerizable with the above-mentioned aromatic vinyl monomers and vinyl cyanide monomers include (meth) acrylic acid ester monomers such as methyl, ethyl, propyl, and n-butyl of acrylic acid and methacrylic acid, maleimide, Maleimides and acrylamides such as n-maleimide, n-methyl maleimide, n-phenyl maleimide and the like can be used.

Methods for preparing the component (C) of the vinyl copolymer are also well known to those skilled in the art, and any of known polymerization methods such as emulsion polymerization, suspension polymerization, bulk polymerization, and continuous polymerization can be used. Can be used.

(D) Modified Vinyl Aromatic Graft Copolymer

In the present invention, the modified vinyl aromatic graft copolymer (D) is obtained by modifying a vinyl aromatic graft copolymer obtained by grafting an aromatic vinyl monomer to a rubbery polymer using an organic lump oxide and a reactive monomer. In this invention, it is preferable to carry out 20-99 weight part graft reaction of said aromatic vinylic monomer. The preparation of the rubbery polymer of the modified vinyl aromatic graft copolymer (D) of the present invention includes at least one rubber selected from the group consisting of diene rubber, ethylene rubber and terpolymer copolymer rubber of ethylene / propylene / diene monomer. Can be used.

The average particle diameter of the rubber particle of the said rubbery polymer is 0.01-0.3 micrometer, Preferably it is 0.02-0.2 micrometer.

When the average particle diameter of the rubber particles is less than 0.01μ, it is difficult to prepare a graft copolymer, and when the average particle diameter is more than 0.3μ, the effect of improving low temperature impact properties through proper morphological control is not much.

In the present invention, the aromatic vinyl monomer of the modified vinyl aromatic graft copolymer is styrene, para t-butylstyrene, alpha-methylstyrene, beta-methyl styrene, vinyl xylene, monochlorostyrene, dichlorostyrene, dibromostyrene, Chlorostyrene, ethyl styrene, vinyl naphthalene, divinylbenzene and the like are used, of which styrene and alpha-methylstyrene are suitable.

Graft polymerization of the aromatic vinyl monomer on the rubbery polymer is also well known to those skilled in the art, and any of emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization may be used. have.

Organic monooxides used in the preparation of the modified vinyl aromatic copolymer of the present invention include diisopropylbenzene hydroperoxide, di-t-butyl peroxide, p-ethane hydroperoxide, t-butyl cumyl peroxide, Dicumyl peroxide, 2, 5-dimethyl 2, 5-di (t-butylperoxy) hexane, di-t-butyldiperoxyphthalate, succinic acid peroxide, t-butyldiperoxybenzoate, tbutylper Roxymaleic acid, t-butylperoxyisopropyl carbonate, methyl ethyl ketone peroxide, cyclohexanone peroxide, etc. can be used. These organic monohydrates may be used alone or in combination of two or more thereof. Among them, dicumyl peroxide is preferable in consideration of reactivity and processability.

Maleic anhydride, maleic acid, itaconic anhydride, fumaric acid, acrylic acid, methacrylic acid ester, etc. may be used as the reactive monomer having an unsaturated carboxylic acid or an anhydride group thereof used in the preparation of the modified vinyl aromatic graft copolymer of the present invention. It is possible to use double maleic anhydride.

In the present invention, the method for producing the modified vinyl aromatic graft copolymer obtained by grafting the unsaturated carboxylic acid or anhydride is not particularly limited, but considering the relatively high working temperature, the vinyl aromatic graft copolymer and organic It is preferable to mix | blend the reactive monomer which has a peroxide and unsaturated carboxylic acid or its anhydride group, and to graft-react in melt kneading state using a binvari mixer or a vented extruder.

The amount of the alpha, beta unsaturated carboxylic acid compound having carboxylic acid or anhydride to the vinyl aromatic graft copolymer is preferably 0.01 to 10 parts by weight, more preferably 100 parts by weight of the total vinyl aromatic graft copolymer. 0.1-7 weight part is good. When the amount of the reactive monomer having an unsaturated carboxylic acid or its anhydride group is less than 0.01 part by weight, compatibility with the resin composition is lowered and there is little effect of improving the low temperature impact resistance, and when the amount is more than 10 parts by weight, it is modified. The production process of the vinyl aromatic polymer becomes difficult, and due to the excessive reaction, there arises a problem that the physical properties of the final resin composition is sharply reduced.

In the preparation of the modified vinyl aromatic polymer, when the organic peroxide is mixed in an amount exceeding 2 parts by weight, thermal stability and physical properties of the final resin composition are remarkably lowered due to decomposition of the resin, so that the amount of the organic peroxide added in the present invention is grafted. It needs to be 0-2 weight part with respect to 100 weight part of copolymers.

The content of the modified vinyl aromatic graft copolymer in the present invention is 1 to 50 parts by weight, preferably 3 to 30 parts by weight. If the content of the modified vinyl aromatic graft copolymer is less than 1 part by weight, there is little effect of improving the low temperature impact resistance of the resin composition of the present invention, and if it exceeds 50 parts by weight, the moldability and productivity of the resin composition are deteriorated, which is not preferable. .

(E) Maleimide Copolymer

Maleimide copolymer (E) which is one component of the thermoplastic resin composition of this invention has 30-70 mol% of aromatic vinylic monomers, 30-50 mol% of maleimide-based monomers, and has unsaturated carboxylic acid or its anhydride group. It is prepared by copolymerizing 1-20 mol% of reactive monomers and 0-35 mol% of other copolymerizable monomers. More preferable compositions are 50 to 60 mol% of aromatic vinyl monomers, 40 to 50 mol% of maleimide monomers, 1 to 10 mol% of unsaturated carboxylic anhydride monomers and 0 to 30 mol% of other copolymerizable monomers.

When the content of the aromatic vinyl monomer of the maleimide copolymer (E) in the present invention is less than 30 mol%, it is difficult to industrially obtain a polymer having a uniform composition, and also the thermal stability, molding processability and other properties of the final product kneaded with polyamide Mechanical properties deteriorate. On the other hand, when the content of the aromatic vinyl monomer is more than 70 mol% or the content of the maleimide monomer is less than 30 mol%, the heat resistance is lowered, and when the content of the maleimide monomer is more than 50 mol%, moldability is poor.

In addition, when the amount of the reactive monomer having an unsaturated carboxylic acid group is less than 1 mol%, compatibility with polyamide is poor, and the average particle diameter of the maleimide copolymer dispersed particles is increased, resulting in poor mechanical properties. When the addition amount exceeds 20 mol%, the average grain size of the maleimide-based airborne molecular particles is reduced, resulting in poor molding processability and lowering in thermal stability of the molded article.

Examples of the aromatic vinyl monomers used in the production of the maleimide copolymer of the present invention as described above include styrene, alphamethylstyrene, vinyltoluene t-butylstyrene, and the like. Mid, N-ethyl maleimide, N-butyl maleimide, N-hexyl maleimide, N-dichlorohexyl maleimide, N-phenyl maleimide, N-trimaleimide and the like can be used.

In the present invention, as the reactive monomer having an unsaturated carboxylic acid or its anhydride group, maleic anhydride, methyl maleic anhydride, 1, 2-dimethyl maleic anhydride, ethyl maleic anhydride, phenyl maleic anhydride, and the like can be used. Nitrile, methyl methacrylate, ethyl (meth) acrylate, butyl methacrylate, digrohexyl methacrylate, decyl (meth) acrylate, octadecyl methacrylate, hydroxyethyl (meth) acrylate, glycidyl A methacrylate monomer is used individually or in combination of 2 or more types.

As a method for preparing these copolymers, an aromatic vinyl monomer, an unsaturated carboxylic anhydride monomer, and other copolymerizable monomers may be used to imidize anhydride acids by reacting with ammonia or primary amines.

There are many known imidization reactions between amine compounds and polymers having anhydride groups in the polymer chain. For example, polymers and amide compounds according to the methods described in Japanese Patent Application Laid-Open Nos. 61-26936 and 62-845. By reacting, the maleimide-type copolymer which has a target imide group can be manufactured. Primary amines for reaction with amides are methylamine, ethylamine, propylamine, butylamine, hexaamine, decylamine, aniline, naphthaleneamine, chlorophenylamine, dichlorophenylamine, bromophenylamine, dibromophenyl Amines and the like.

The imidation reaction may be carried out by using an autoclave in a molten state, in a molten state or in a suspended state, or by reacting in an molten state in an extruder. Examples of the solvent used in the melting reaction include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and dichlorohexanone, ethers such as tetrahydrofuran and 1 and 4-dioxane, aromatic hydrocarbons such as toluene and xylene, and dimethyl bromine. Amides, N-methyl-2-pyrroladon and the like can be used.

The imidation reaction temperature is good in the range of 50-350 degreeC, and the range of 100-300 degreeC is especially preferable. The imidation reaction may be carried out in the presence of a catalyst or without using a catalyst. Examples of the catalyst which can be used when the catalyst is used are trimethylamine, triethylamine, tributylamine, N, N-dimethylaniline, N, Tertiary amines, such as N-dimethylamine, are preferable.

Other additives may be added to the thermoplastic resin composition of the present invention depending on the application. Specifically, in the case of adding an inorganic filler such as glass fiber carbon fiber, talc, silica, mica, alumina, mechanical strength and heat deformation The physical properties such as heat distortion temperature (HDT) can be improved.

It is also possible to add other ultraviolet absorbers, antioxidants, flame retardants, lubricants, dyes, pigments and the like to the thermoplastic resin composition of the present invention in addition to the above.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are merely specific examples of the present invention and should not be construed as limiting or limiting the protection scope of the present invention.

EXAMPLE

First, the respective components of the thermoplastic resin composition used in the present embodiment will be described.

(A) polyamide resin

In the examples of the present invention, two kinds of polyamide resins ((A-1) and (A-2)) were used. (A-1) is nylon 6 (trade name: KN-171) of Kolon Corporation, and (A-2) is nylon 66 (trade name: 21SP) manufactured by Monsanto, USA.

(B) Vinyl Graft Copolymer

In the vinyl graft copolymer (B) used in the embodiment of the present invention, 1000 g of a composition consisting of 400 g of polybutadiene latex having a rubber particle diameter of 0.3 μ (based on solids), 390 g of styrene monomer, and 160 g of acrylonitrile were added to the reactor. 2 g of t-dodecyl mercaptan, 5 g of potassium persulfate, and 5 g of sodium moleate were added thereto, followed by emulsion polymerization to obtain a vinyl graft copolymer.

(C) vinyl copolymer

The vinyl copolymer (C) used in the embodiment of the present invention was prepared by adding 710 g of styrene and 270 g of acrylonitrile to the reactor, adding 5 g of t-dodecyl mercaptan and then suspending polymerization.

(D) Modified Vinyl Aromatic Graft Copolymer

In the embodiment of the present invention modified vinyl aromatic graft copolymer (D) was prepared and used as follows.

(D-1): 300 g of polybutadiene latex (based on solid content) and 700 g of styrene having a rubber particle diameter of 0.1 μ was placed in a reactor, and 5 g of potassium persulfate and 5 g of sodium moleate were added to the mixture to emulsify and Vinyl aromatic graft copolymer (D-1) was prepared.

(D-2) to (D-6): after mixing the graft copolymer (D-1), maleic anhydride and dicumyl peroxide in the composition shown in Table 1 below, L / D = 30, ψ Pelletized polymers (D-2) to (D-6) were prepared using a single screw extruder having a diameter of 30 mm. At this time, the temperature of the cylinder was set to 150 ~ 220 ℃, the screw rotation speed was set to 100rpm. The content of the grafted maleic anhydride in the results shown in Table 1 was calculated by measuring the area of the characteristic band (1780 cm ^-1 ) of maleic anhydride by infrared spectroscopy after reprecipitation of the prepared pellets with chloroform / methanol solution.

TABLE 1

(E) Maleimide Copolymer

In the examples of the present invention, two kinds of maleimide-based copolymers [(E-1) and (E-2)] were used. (E-1) is POLYIMILEX PSX-371 of Nippon Catalysts Co., Ltd., and (E-2) is MALECCA MS-NA of Nippon Electrochemistry.

Example 1-5

In Example 1-5, the polyamide polymer (A), the vinyl graft copolymer (B), the vinyl copolymer (C), the modified vinyl aromatic graft copolymer (D), and Malay, which are the resin composition components of the present invention, The modified vinyl aromatic graft copolymer (D) in the mid-based copolymer (E) is fixed in the type and content of the other components thereof, while changing the type of (D) while mixing the resin in the composition ratio as shown in Table 2 Henschel mixer After mixing at 45mm diameter, extruder was extruded at 230 ~ 270 ℃ to make pellets, dried at 80 ℃ for 6 hours, and mold temperature of 240 ~ 280 ℃, mold temperature 60 ~ 80 ℃ at 6 oz injection machine. Injected to prepare a physical specimen and to evaluate the impact strength is shown in Table 2 together.

[Property Test Method]

Izod impact strength-ASTM D648 (1/4, 1/8 notch, unit kg / cm / cm)

TABLE 2

As confirmed through the results in Table 2, it can be seen that the impact strength at low temperatures is lowered when using a modified vinyl aromatic copolymer having a maleic anhydride content of less than 0.1 part by weight or more than 7 parts by weight.

[Comparative Example 1-7]

0.2 parts by weight of an antioxidant and a thermal stabilizer were added, except that the composition of the resin as shown in Table 3 was changed, the physical properties of the specimen were prepared in the same manner as in Example 1, and the impact strength thereof was shown in Table 3 below.

TABLE 3

# 1) ABS / nylon alloy (Monsanto, USA)

Through the results in Table 3, it can be seen that the impact strength at low temperature is sharply lowered unless the non-modified D-1 or any one of the polymers (B), (D) or (E) is added.

Claims (5)

(A) 10 to 90 parts by weight of a polyamide resin; (B) Vinyl-based graft copolymer 10 to 40 to 90 parts by weight of the rubbery polymer obtained by graft polymerization of 40 to 90 parts by weight of an aromatic vinyl monomer and 75 to 30 parts by weight of a monomer mixture of 60 to 10 parts by weight of a vinyl cyanide monomer. 90 parts by weight; (C) 0 to 20 parts by weight of a vinyl copolymer obtained by copolymerizing 40 to 90 parts by weight of an aromatic vinyl monomer, 60 to 10 parts by weight of a vinyl cyanide monomer, and 0 to 40 parts by weight of other vinyl monomers copolymerizable with these; (D) Unsaturated carboxylic acid or in the state in which 0-2 weight part of organic peroxides were added with respect to 100 weight part of graft copolymers which graft-polymerized 20-99 weight part of aromatic vinylic monomers to 1-80 weight part of rubbery polymers. 1 to 50 parts by weight of the modified vinyl aromatic graft copolymer obtained by melt kneading and kraft-reacting 0.01 to 10 parts by weight of a reactive monomer having the anhydride group; And (E) 30 to 70% of aromatic vinyl monomers, 30 to 50 mol% of maleimide monomers, 1 to 20 mol% of unsaturated carboxylic acids or reactive monomers having anhydride groups thereof, and other copolymerizable monomers of 0 to 35 mol% A thermoplastic resin composition having excellent impact strength, which is composed of 1 to 30 parts by weight of a mid-based copolymer. The method of claim 1, The thermoplastic resin composition having excellent impact strength, wherein the rubbery polymer is one selected from the group consisting of diene rubber, acrylic rubber, and rubber of ternary copolymer of ethylene-propylene-diene monomer. The method of claim 1, The thermoplastic resin composition having excellent impact strength, characterized in that the average particle diameter of the rubber particles of the rubbery polymer used in the vinyl graft copolymer (B) is 0.1 to 1 µ. The method of claim 1, The thermoplastic resin composition excellent in impact strength, wherein the average particle diameter of the rubber particles of the rubbery polymer of the modified vinyl aromatic graft copolymer (D) is 0.01 to 0.3 µ. The method of claim 1, Thermoplastic resin excellent in impact strength, characterized in that the unsaturated carboxylic acid or the reactive monomer having an anhydride group is one selected from the group consisting of maleic anhydride, methyl maleic anhydride, 1, 2-dimethylmaleic anhydride and ethyl maleic anhydride. Composition.