KR100501511B1 - The Composition of Polyamide resin - Google Patents

Abstract

The present invention relates to a polyamide resin composition, and more particularly, by adding a thermoplastic rubber elastomer and a graft copolymer containing a particulate inorganic filler and an acid functional group to a polyamide resin, such as high rigidity, high heat resistance and impact resistance. It has excellent physical properties and no flow mark, so it has excellent surface properties and is suitable for application to parts that require painting. Improved to secure stable dimensional stability because no post-shrinkage occurs by secondary processing. It relates to a polyamide resin composition.

Description

The composition of polyamide resin

The present invention relates to a polyamide resin composition, and more particularly, by adding a thermoplastic rubber elastomer and a graft copolymer containing a particulate inorganic filler and an acid functional group to a polyamide resin, such as high rigidity, high heat resistance and impact resistance. It has excellent physical properties and no flow mark, so it has excellent surface properties and is suitable for application to parts requiring painting. Improved to secure stable dimensional stability because no post-shrinkage occurs by secondary processing. It relates to a polyamide resin composition.

Recently, the development of the electric / electronics industry centering on the automobile industry has accelerated the development of the plastics industry, and the development of the plastics industry has been replaced by plastic materials, and thus many applications have been applied to the entire industry centering on automobiles. The purpose of replacing materials is actively progressed in terms of light weight, low manufacturing cost, improved design freedom, and simplified manufacturing process.

The lead filler door for automobile is a part installed to prevent theft of injected fuel and direct exposure of the fuel inlet as a part of the fuel input unit connected to the fuel tank, the fuel inlet tube and the fuel inlet. Conventionally, steel (STEEL) of the same material has been applied, but in order to prevent the deterioration of merchandise due to corrosion due to chemical corrosion caused by chemical corrosion caused by fuel and peeling of the coating by friction with the injector. The material is being applied.

For example, the lead filler door is recently painted while passing through the coating line with the vehicle body during the painting process during the automobile manufacturing assembly process, in this case, a dimensional defect may occur due to post-shrinkage at high temperatures. In particular, the step difference with the vehicle body is a non-uniformity caused by the contraction anisotropy, which is a reality that has become a major problem in the commerciality, such as inhibiting the appearance.

In particular, as part of the recent shortening of the process, the coating process is done online (On-line). At this time, the working temperature is a high temperature of 190 ~ 200 oC, and post-shrinkage at this temperature may cause problems of product applicability. Therefore, improvement is essential.

Among the many plastic materials, polyamide resin is one of the five engineering plastic materials and has been spotlighted as having excellent mechanical properties, molding processability, durability, chemical resistance, and weather resistance. In particular, polyamide resins for automobile parts have been applied to engine products and exterior products.

Although such polyamide resins have very excellent physical properties, there have been some problems, and a series of studies have been conducted to improve them. In other words, due to moisture absorption, the rigidity is poor, or because it is made of a crystalline polymer, the impact resistance is poor, there is a disadvantage that post-shrinkage occurs during secondary processing in a high-temperature atmosphere is urgent improvement of this situation.

That is, the water absorption of the conventional polyamide resin has advantages and disadvantages, and the advantage is that the toughness is improved while causing problems such as heat resistance and rigidity. Therefore, in order to minimize moisture absorption, a series of researches are being conducted to improve alloys or other minerals with other resins. In addition, in order to improve impact resistance, a rubber component commonly referred to as an impact agent is used and an alloying method is used. In order to further improve other additional mechanical properties, a method of additionally adding a third additive is used. In addition, in order to improve post-shrinkage, an amorphous resin or an inorganic filler is added.

However, even if these various methods are applied, it is very difficult to satisfy the physical properties and inherent characteristics required for the products. As a representative example, the fluidity is poor, the surface of the product is poor, the heat resistance is insufficient, discoloration or warping may occur during high temperature coating, manufacturing cost increases due to the use of the alloying third or fourth additive Problems such as the following may occur again.

The technique of improving the physical properties by strengthening the inorganic material in the polyamide resin as described above has been developed over a long time in the art, but the inorganic material alone is used not only in the physical properties of the polyamide resin, Since many problems occur even when applied to the product, the development of technology by the method of adding a third additive commonly used.

Problems that occur when the inorganic material is used alone in the polyamide resin are typical surface defects such as poor impact strength due to the lack of compatibility between the inorganic material and the polyamide resin, flow marks generated when forming the product. As a solution to the above problems, the surface coating technology of inorganic materials and the addition of coupling agents have made a number of technical advances, and have been developed to improve the physical properties of products made of polyamide resins. The technology of additionally introducing 3 resins is being developed as the mainstream.

Known as a technology developed to improve the physical properties of the polyamide resin as described above are as follows.

U.S. Patent No. 4131591 proposes a technique for adding inorganic talc and ololastonite to polyamide resin, and U.S. Patent No. 3843591 proposes a coupling agent for improving interfacial adhesion between inorganic and polyamide. Proposed technology.

Japanese Patent Laid-Open No. 6070643 has proposed a technique for adding cray in inorganic materials, and Japanese Patent Laid-Open No. 5817440 has proposed a technique for improving surface defects using calcium oxide (CaO) and magnesium oxide (MgO).

The polyamide resin according to the above-mentioned US Patent No. 431591 has insufficient impact resistance and the coupling agent according to US Pat. No. 38,43591 has excellent effects such as stiffness, impact resistance, heat resistance and surface properties, but due to post-shrinkage. Dimensional instability still remains, and manufacturing costs rise, which is not economical.

In addition, even with the technique proposed by the Japanese Patent Application, the technical effect of the specific field is excellent, but it cannot satisfy all of the rigidity, heat resistance, impact resistance, surface properties, and high temperature post-shrink dimensional stability.

In another technical field, Japanese Patent Application No. 87235652 has proposed an alloy with a high glass transition temperature polyphenylene-based resin or unsaturated carboxylic acid-containing rubber component to satisfy all physical properties such as impact resistance, heat resistance, and rigidity. However, the post-shrinkage dimensional stability could not be solved, and Korea Patent No. 194-0014663 also proposed a blended technique with polyolefin and acid functional rubber, but due to the increase of crystalline components and the addition of olefins, It did not solve the technical problem of shrinkage.

That is, even in the case of the polyamide resin developed by the above-described techniques can not satisfy all the physical properties or intrinsic properties of the product, many restrictions remain when applied to various products.

Accordingly, the inventors of the present invention have made efforts to solve the problems of the prior art according to the improvement of the polyamide resin as described above, the thermoplastic rubber elastomer containing an inorganic reinforcing filler and an acid functional group in the polyamide-based resin blended in a specific ratio and When the graft copolymer is added, the mechanical properties such as impact resistance, heat resistance, and rigidity are excellent, and a beautiful appearance can be obtained because no flow mark occurs on the surface when forming the product, and the dimension is stable due to the low post-shrinkage at high temperature. The present invention was completed to know that a molded article can be produced.

Therefore, an object of the present invention is to provide a polyamide resin composition having excellent dimensional stability at high temperature.

The present invention relates to a polyamide resin composition comprising: 48 to 63.5 wt% of base resin, 35 to 45 wt% of particulate inorganic filler, and acid functional group, comprising polyamide 6 resin and polyamide 66 resin in a weight ratio of 1: 1 to 3.2 1 to 4% by weight of the thermoplastic rubber elastomer and 30 to 60% by weight of the aromatic vinyl compound, 30 to 60% by weight of the vinyl cyan compound and 5 to 15% by weight of the acrylic acid alkyl ester mixture. Characterized by comprising a polyamide resin composition comprising 3% by weight.

The present invention as described above is to improve the rigidity and heat resistance by reinforcing the inorganic material based on the polyamide resin, fibrous inorganic filler is required because the excellent surface smoothness is required to apply the polyamide resin to products requiring paintability It is a technical feature to use particulate inorganic fillers which are not.

Inorganic substances include fibrous inorganic fillers such as glass fiber or carbon fiber, talc (talc, talc), mica (mica), cray (clay) and calcium carbonate (CaCO _3). ), Which collectively refers to particulates (Particles) such as Ollastonite, and the like, the polyamide resin composition according to the present invention in the form of particulates other than the conventional fibrous inorganic fillers Apply mineral filler.

In general, when a resin containing a fibrous inorganic filler is applied to a product, in particular, when forming a thin thin film product such as a lead filler product as an automotive part, physical properties such as heat resistance and rigidity are excellent, but shrinkage anisotropy There is a difference in shrinkage in the longitudinal and transverse directions, there is a problem that the smoothness of the product is worse when applying a resin containing a fibrous inorganic material than when applying a resin not using an inorganic material,

In the present invention, the above problems are solved by adding a non-fibrous particulate inorganic filler to the polyamide resin composition, thereby making it possible to prepare a resin composition having excellent surface smoothness and excellent coating adhesion and glossiness after coating. . That is, an aminosilane-based coupling agent is treated among the inorganic fillers, and a particulate inorganic material having a particle size of 0.1 to 2 μm is used, and a cubic shape, that is, a non-leafy inorganic material, is used. The inorganic substance whose ratio of length and thickness (henceforth L / D) is 1-5 is used.

The small size L / D inorganic material treated with the aminosilane-based coupling agent can solve the poor paintability due to the impact resistance and the generation of flow marks when forming the product. In addition, it is possible to secure post-shrinkage stability at high temperature. In the case of leaf-laminated inorganic materials or large L / D inorganic materials, there are problems of shrinkage anisotropy and post-shrinkage when post-shrinkage occurs such as online coating at high temperature. We tried to solve this problem by using inorganic material with L / D lower than certain value.

In addition, a thermoplastic rubber having an acid functional group, which is an optimal additive, is added within a range in which post-shrinkage does not occur and heat resistance is not impaired for a synergistic effect of impact resistance. It is a second technical feature of the present invention to additionally add a graft copolymer composed of aromatic vinyl and vinylcyanide compounds and alkyl esters for high temperature post-shrinkage stability.

The polyamide resin used in the present invention is constituted by adding an inorganic substance using a polyamide 6 resin and a polyamide 66 resin as a base resin and adding a thermoplastic rubber elastomer and a graft copolymer containing an acid functional group.

   Hereinafter described in detail for each component of the polyamide resin composition according to the present invention.

(1) polyamide 6, polyamide 66 resin

   The polyamide resin to be used in the present invention can be represented by the following formulas (I) and (II) as ordinary polyamide 6 and polyamide 66 resins.

-(NH- (CH ₂ ) 5-CO) _n ---- polyamide 6 (I)

-(NH- (CH ₂ ) ₆ -HN-CO- (CH ₂ ) ₄ -CO) _n ---- polyamide 66 (II)

N is an integer of 500-15,000 here.

The polyamide 6 resin of the present invention is generally a method for producing polyamide 6-7.17 parts by weight of water, 0.004 parts by weight of foam inhibitor, and tris- (2.4-dibutyl butylphenyl), which is heat-resistant, based on 100 parts by weight of caprolactam. 0.09 parts by weight of Iganox B 1171 (manufactured by Ciba-Geigi), a 1: 1 mixture of phosphite and N, N'-hexamethylene bis (3.5-dibutyl butyl-4-hydroxy-hydrocinamide), 260 ° C Into the reaction tube of, the pressure was raised to 15 Kg / ㎠ and reacted for 1 hour, the pressure was maintained for 30 minutes and then the pressure was gradually dropped to proceed with the reaction for 2 hours at the same pressure as the atmosphere The reaction may be further performed for about 1 hour by reducing the pressure to -360 mmHg, and then the reaction may be terminated while adding nitrogen to prepare the desired polyamide 6 resin.

Polyamide 66 resin is a polyamide resin polymerization autoclave equipped with a stirrer, a heat sensor, a temperature controller, a steam reflux cooler, and a device capable of circulating water, and a hexamethylenediamine adipate salt as a polyamide polymerization raw material (hereinafter, AH salt) and the appropriate amount of water according to the concentration of this AH salt are added, and the temperature is raised and dissolved uniformly using a stirrer, and then various additives are added. A uniform slurry using a mixed solvent of methanol and water in a container for preparing a raw material. It was prepared to put into the reaction tube in which the AH salt is dissolved can be prepared to have the desired properties according to the conventional polyamide 66 production process. The manufacturing process is made under the conditions shown in Table 1 below.

In addition to the above raw materials, a small amount of hexamethylenediamine and an antifoaming agent can be added as a viscosity stabilizer and an excess additive, and oxygen is removed while purging high purity nitrogen gas after all the raw materials are put into the reaction tube. The desired polyamide 66 resin can then be obtained.

In Table 1, in the step-up, the step-up temperature, as the temperature increases, the steam is filled in the autoclave, causing a pressure increase. At this time, it raises to 230 degreeC over 60 minutes from the point which temperature is 120 degreeC. Then, when the pressure reaches 17.5 Kg / cm 2, the pressure is maintained while flowing steam to the outside and the temperature is raised to about 250 ° C. The pressure is lowered to atmospheric pressure for 70 minutes while flowing out to the outside, and then maintained for 30 minutes and stabilized, followed by a discharge process in which nitrogen is added at about 2 to 2.5 Kg / cm 2 to prepare a desired polyamide 66 resin.

The polyamide 66 and polyamide 6 obtained as described above were prepared in a chip form so as to be suitable for the preparation of the polyamide resin composition of the present invention, and then dried in a dehumidifying dryer at 90 ° C. for 5 hours. It is preferable.

In the case of the produced polyamide 6 and polyamide 66 resin, it is preferable to use the thing of relative viscosity 2.4-3.4 (20 degreeC, the polymer 1g solution in 100 ml of 96% sulfuric acid). If the viscosity of the polyamide resin used is less than the above range, the rigidity and impact resistance is lowered. If the viscosity of the polyamide resin exceeds the above range, the surface defects and difficulty of molding occur after molding the product due to poor fluidity.

The polyamide 6 and 66 resins prepared in this way have a polyamide 6: polyamide resin 66 of 1: 1 to 3.2 by weight ratio, and the amount of polyamide 66 resin should be relatively high. If the use ratio of polyamide resin 66 is less than 1, the heat resistance is poor, and if the ratio exceeds 3.2, there is a problem that a flow mark is generated on the painted surface because the crystallization rate is increased during molding of the product.

The base resin composed of the above ratio is used 48 to 63.5% by weight based on the total polyamide resin composition, depending on the content of the inorganic materials, thermoplastic rubber elastomer and graft copolymer constituting the polyamide resin of the present invention It is decided.

  (2) particulate inorganic filler

The inorganic material used in the present invention is a particulate, having a particle size of 0.1 to 2 μm, and having a surface-coated surface with an amino silane. If the particle size is less than 0.1 μm, the stiffness reinforcing effect and the heat resistance reinforcing effect are insignificant, and if the particle size is larger than 2 μm, the shrinkage anisotropy increases, and the phenomenon of inorganic matters appearing on the surface of the molded article is undesirable. In other words, there is a restriction on the size of the particulate inorganic material used, 1 to 5 based on the L / D standard, when the L / D is less than 1 used inorganic material can be obtained the stiffening and heat resistance strengthening effect according to the inorganic addition effect There is no problem, and if it exceeds 5, the shrinkage difference between the flow direction and the right angle flow direction occurs around the gate when forming the product, so that the shrinkage rate increases during high temperature post-shrinkage, and additionally, there is a problem of shrinkage anisotropy, causing warpage. It is not desirable to be

In addition, when the inorganic material is surface treated with a reactive functional group (coupling agent), the coupling agent is adsorbed around the filler to increase the adhesion affinity between these fillers and the polyamide resin, or the coupling agent causes a molecular reaction with the inorganic material to couple the polymer. The ring agent itself can behave similarly to polyamide during processing, resulting in better compatibility with the resin.

The amount of the inorganic material is used 35 to 45% by weight based on the total weight of the polyamide resin composition, but if the amount is less than 35% by weight, the rigidity and heat resistance is poor, there is a problem that the post-shrinkage is increased, 45% by weight If exceeded, there is a problem that the impact strength is lowered, the inorganic material is exposed on the surface of the molded article, and the flow mark is excessively generated.

  (3) thermoplastic rubber elastomer

Thermoplastic rubber elastomers are widely known as impact resistance and water resistant modifiers of conventional polyamide resins, and have a functional group having excellent reactivity with a matrix functional group of polyamide, that is, an amide group, in the presence of conjugated diene rubber. Unsaturated carboxylic acids or α, β-unsaturated anhydrides or derivatives thereof, specifically, for example. Maleic anhydride, itaconic anhydride, citraconic anhydride, acrylic acid, methacrylic acid, allyl succinic acid, 2-dicarboxylic acid, maleic acid, fumaric acid, dimethyl maleic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, allyl succinic acid Anhydrides and the like.

In the present invention, maleic anhydride is grafted, and when conjugated diene rubber is applied, butadiene must be included. Specifically, for example, polybutadiene, styrene-butadiene random or block copolymer, styrene-ethylene A single or a mixture of two or more selected from -butadiene copolymer, styrene-ethylene-butadiene-styrene copolymer, acrylonitrile-butadiene copolymer and butadiene-isoprene copolymer may be used. In this case, when the butadiene-styrene copolymer and the styrene-ethylene-butadiene-styrene copolymer are used, a preferable effect can be obtained, which is more preferable when the styrene-ethylene-butadiene-styrene copolymer is used.

At this time, the grafted maleic anhydride content is 0.4 to 5% by weight, but less than 0.4% by weight is incompatible with polyamide, and when it exceeds 5% by weight, the alloy efficiency decreases when kneading the composition. There is a problem,

The thermoplastic rubber elastomer is used in an amount of 1 to 4% by weight in the total polyamide resin composition. When the amount of the thermoplastic rubber elastomer is less than 1% by weight, the effect of improving impact strength is small. There is a problem that the post-shrinkage is large.

(4) graft copolymer

In order to improve the impact strength of the polyamide resin composition of the present invention, the beautiful properties of the product surface, high temperature post-shrink dimensional stability and paintability, the graft copolymer composed of an aromatic vinyl, a vinyl cyan compound, and an acrylic acid alkyl ester compound may be used. 0.5-3 weight% is used in an amide resin composition.

Wherein the aromatic vinyl compound is selected from among styrene, α-methyl styrene, methyl styrene, vinyl xylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, pt-butylstyrene, ethylstyrene vinylnaphthalene and o-methylstyrene. Selected solely or a mixture of two or more thereof, preferably polystyrene. The vinyl cyan compound may be selected from acrylonitrile, methacrylate and methyl ethyl methacrylate, and is preferably acrylonitrile.

The aromatic vinyl compound and the vinyl cyan compound are contained in 30 to 60% by weight of the total graft copolymer, respectively, if the content is less than 30% by weight, the stiffness and heat resistance of the graft copolymer is lowered and the final polyamide Also in the resin composition, the effect of improving heat resistance, rigidity and post-shrinkage property is insignificant, whereas when used in excess of 60% by weight, the graft copolymer has a problem of incompatibility with the polyamide resin, resulting in a decrease in impact strength and flexural modulus. Results in.

Further, the alkyl acrylate ester compound includes methyl methacrylate, methyl acrylate, ethyl acrylate, hexyl acrylate, propyl acrylate, butyl acrylate, dodecyl acrylate, phenyl acrylate, benzyl acrylate, ethyl methacrylate, Methacrylic acid esters such as butyl methacrylate, hexyl methacrylate, amyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, phenyl methacrylate and benzyl methacrylate In the present invention, a more preferable effect may be obtained when a single or a mixture of two or more selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate is used in the methacrylic acid ester.

The acrylic acid alkyl ester compound may be used in 5 to 15% by weight of the graft copolymer, if the content is less than 5% by weight, the compatibility with the polyamide resin is poor, there is a problem that mechanical properties, in particular impact strength is lowered On the other hand, if the content exceeds 15% by weight, the compatibility is good but heat resistance is poor.

The graft copolymer having the above composition and content was charged with 150 parts by weight of water based on 100 parts by weight of the monomer selected from acrylonitrile monomer, styrene monomer and methacrylic acid ester compound, and heated to a reaction temperature of 70 ° C. under a gas nitrogen atmosphere. Next, a primary monomer phase containing 0.6 parts by weight of tertiarydecylmercaptan, 0.5 parts by weight of sodium stearate, and 0.5 parts by weight of potassium persulfite was prepared, and a solution prepared by dissolving 0.1 parts by weight of potassium persulfate in 50 parts by weight of water was prepared. The primary polymerization is carried out for 3 hours while being added separately from the primary monomer phase. Then, a secondary monomer phase containing 0.6 parts by weight of tertiarydecylmercaptan was prepared again with respect to the reaction mixture, and a solution prepared by dissolving 0.1 parts by weight of potassium persulfate in 50 parts by weight of water was separated and added for 3 hours. During the second polymerization. After completion of the reaction, the reactor was maintained at 70 ° C. for 2 hours to complete the polymerization reaction, and 3 parts by weight of aluminum sulfate was added to the resin for salting, filtering, washing with water and drying to obtain a graft copolymer. .

The graft copolymer prepared as described above uses 0.5 to 3% by weight based on the total polyamide resin composition. When the amount of the graft copolymer is less than 0.5% by weight, the improvement of high temperature post-shrinkage stability and product surface beauty characteristics is insignificant. When the weight percentage is exceeded, the heat resistance may be deteriorated, which may cause discoloration during high temperature coating.

 (5) other

On the other hand, a heat resistant agent or a weathering agent can be used within the scope of not impairing the object of the present invention, and as heat resistant agent, tris- (2,4-dibutylbutylphenyl) -phosphate having an amide group and N, N'-hexamethylene Iganox B1171 (trade name, Ciba-Geigy Co., Ltd.), a 1: 1 mixture of bis (3,5-dibutylbutyl-4-hydroxy-hydrocinamide), may be used.A light stabilizer called weathering agent absorbs ultraviolet rays. Hydroxyphenylbenzotriazolotinuvin234 (trade name, Ciba-Geigy Co.) and peroxide decomposer generated by ultraviolet rays and another substance that scavengers radicals. Hindered with tetramethylpiperidine structure Tinuvin 770 (trade name, Ciba-Geigy Co., Ltd.), a light stabilizer of a amine (Hindered Amine) system, may be used, and in the present invention, a small amount of the heat-resistant and weather-resistant agents is used.

The mixer used to prepare the polyamide composition of the present invention may be prepared by kneading at 270 to 285 ° C. using a twin screw extruder, and in order to maximize the kneading of the resin composition, the extruder having three inlets may be used. It is preferable to inject polyamide 6 resin and polyamide 66 resin into the primary inlet, thermoplastic rubber elastomer and graft copolymer in the secondary inlet, and minerals into the tertiary inlet.

In addition, it is preferable to minimize the residence time in order to prevent thermal decomposition of the composition during melt kneading, and the optimum screw speed adjustment is necessary in consideration of the dispersibility in the present composition, if the rotation speed of about 200 ~ 300 rpm is suitable.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Examples 1-10 and Comparative Examples 1-17

    Next, melt kneading in a twin screw extruder heated to 270 ℃ according to the composition of Table 2 and dried in a chip state at 90 ℃ for 5 hours using a dehumidifying dryer and melt kneading using a heated screw injection machine. Each specimen was made by temperature.

Experimental Example

The physical properties of the resin compositions prepared according to Examples 1 to 10 and Comparative Examples 1 to 17 were evaluated based on the following evaluation method.

<Shock strength>

A 1/4 inch specimen was prepared according to ASTM D256, and the Izod Notched impact strength was measured at room temperature and low temperature (-30 ° C).

Flexural Modulus

A 1/4 inch specimen was prepared and measured according to ASTM D790.

<Heat Deflection Temperature>

Measurements were made at 4.6 kg / cm 2 of rated load using 1/4 inch specimens in accordance with ASTM D648.

<Surface properties>

The resin composition of the present invention made after melt kneading was dried in a chip state at 90 ° C. for 5 hours using a dehumidifying dryer, and was 150 mm wide, 100 mm long and 2.8 mm thick with a Nissei 150-ton injection molding machine. Using a square die of direct gate type with a diameter of 7 mm and a length of 80 mm in the cavity, the injection temperature is fixed at 270 ° C and the mold temperature at 20 ° C. / Cm2, injection time 3 seconds Cooling time 10 seconds In the molded article released under conditions, especially the flow mark of the gate area was visually observed.

Postshrinkage Stability

After observing the surface characteristics, the specimens were left for 48 hours in an atmosphere of 23 ° C and 50% absolute humidity using a rectangular specimen prepared for observing surface characteristics, and the dimensions of the longitudinal direction were evaluated (initial length), and then the oven was heated at 190 ° C. After the specimen was placed in an unloaded state, it was taken out one hour later, and after being left for 48 hours in an atmosphere of 23 ° C. and 50% absolute humidity, the dimension in the longitudinal direction was also evaluated (later length), and the dimensional change rate was calculated by the following equation (1). In case of more than 0.5%, it was considered bad.

                          Later Length (L)-Initial Length (Lo)

      Dimensional rate of change (%) = ------------------------------------- X 100

                                   Initial Length (Lo)

As shown in Table 3, the polyamide resin composition of the present invention showed that the impact strength at room temperature is 9 kgcm / cm or more, it can be seen that the impact strength at low temperature is improved than the comparative example, the flexural modulus is It can be seen that the resistance to heat was improved to 50,000 kg / cm 2 or more, and the heat deformation temperature (4.6 kg / cm 2 load) was higher than 210 ° C., indicating that the heat resistance was improved. In addition, after painting, the appearance was beautiful without a flow mark on the painted surface, and after aging at 190 ℃ for 1 hour, the dimensional change rate appeared to be 0.5% or less, which greatly reduced the dimensional deformation caused by the pepper shaft at high temperature. It can be seen.

Therefore, when applied to a product group requiring a typical painting process, for example, an automotive exterior product, problems such as poor dimension due to post-shrinkage at high temperature are remarkably improved, and thus a product having excellent dimensional stability and beautiful appearance can be manufactured.

As described above, the polyamide resin composition of the present invention has excellent mechanical properties, high stiffness, good flexural modulus, high heat resistance, good physical properties called heat deformation temperature, and high impact resistance, good physical properties called impact strength. It can be provided a composition excellent in application to parts requiring rigidity, heat resistance, and impact resistance. Furthermore, the composition to be prepared does not have a flow mark or the like generated on the surface during the molding process of the product, so that coating or the like can be provided. It is an excellent composition that can get a beautiful appearance when applying the product you need,

Therefore, the composition of the present invention in terms of product use is basically applied to exterior parts that require stiffness, impact resistance, and heat resistance, and surface parts that require beautiful surfaces, and exterior parts of paint specifications requiring stability against post-shrinkage in a high temperature atmosphere. In the case of suitable resin composition, typical applications include automotive fillers such as lid filler doors, air intake garnish outside door handles and cooker rings with electronic parts. As an excellent composition for the application of), it is a polyamide resin composition that can obtain a desirable effect, especially when applied to the lead filler door products of automobiles,

In addition, it is possible to produce a composition having excellent performance at a low manufacturing cost can satisfy the excellent performance and economics.

Claims (14)

In the polyamide resin composition, 48 to 63.5 weight percent of base resin comprising polyamide 6 resin and polyamide 66 resin in a weight ratio of 1: 1 to 3.2, 35-45 weight% of particulate inorganic fillers, 1 to 4% by weight of an acid functional group grafted thermoplastic rubber elastomer, and 0.5 to 3% by weight of graft copolymer consisting of 30 to 60% by weight of aromatic vinyl compound, 30 to 60% by weight of vinyl cyan compound and 5 to 15% by weight of acrylic acid alkyl ester mixture Polyamide resin composition, characterized in that consisting of. The polyamide resin composition according to claim 1, wherein the particulate inorganic filler has a particle size of 0.1 to 2 mu m and a ratio of length and thickness to 1 to 5. The polyamide resin composition according to claim 1 or 2, wherein the particulate inorganic filler is surface-treated with an amino silane coupling agent. The polyamide resin composition of claim 1, wherein the particulate inorganic filler is selected from talc, mica, cray, calcium carbonate, caCO ₃ , and olollastonite. The polyamide resin composition according to claim 1, wherein the thermoplastic rubber elastomer is a conjugated diene rubber. 6. The polyamide resin composition according to claim 1 or 5, wherein the thermoplastic rubber elastomer is a conjugated diene rubber containing butadiene. 7. The thermoplastic rubber elastomer according to claim 6, wherein the thermoplastic rubber elastomer is polybutadiene, styrene-butadiene random or block copolymer, styrene-ethylene-butadiene copolymer, styrene-ethylene-butadiene-styrene copolymer, acrylonitrile-butadiene copolymer and butadiene A polyamide resin composition, characterized in that it is one or a mixture of two or more selected from isoprene copolymers. The polyamide resin composition according to claim 1, wherein the acid functional group is graft bonded to 0.4 to 5 parts by weight based on 100 parts by weight of the rubber elastomer. The polyamide resin composition according to claim 1 or 8, wherein the acid functional group is selected from α, β-unsaturated carboxylic acid or α, β-unsaturated anhydride and derivatives thereof. The acid functional group according to claim 9, wherein the acid functional group is maleic anhydride, itaconic anhydride, citraconic anhydride, acrylic acid, methacrylic acid, allyl succinic acid, 2-dicarboxylic acid, maleic acid, fumaric acid, dimethyl maleic acid, maleic anhydride, and ita Polyamide resin composition, characterized in that it is selected from chonic anhydride, citraconic anhydride and allyl succinic anhydride. The polyamide resin composition according to claim 1, wherein the acrylic acid alkyl ester is one or a mixture of two or more selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate. The method of claim 1, wherein the aromatic vinyl compound is styrene, α-methyl styrene, methyl styrene, vinyl xylene, monochlorostyrene, dichlorostyrene, monobromostyrene, dibromostyrene, pt-butylstyrene, ethyl styrene vinyl naphthalene And o-methyl styrene, or a mixture of two or more thereof. The polyamide resin composition according to claim 1, wherein the vinyl cyan compound is selected from acrylonitrile, methacrylate and methylethyl methacrylate. It is manufactured with the composition of claim 1, the impact strength of 9 kgcm / cm or more, flexural modulus of 50,000 kg / ㎠ or more, heat deformation temperature (4.6 kg / ㎠ load) of 210 ℃ or more, after painting there is no flow mark, Polyamide resin composition, characterized in that the dimensional change rate (Aging at 190 ° C for 1 hour) is 0.5% or less.