KR101475012B1 - polyamide resin composition - Google Patents

Abstract

The present invention relates to a resin composition for unpainted resin which can be mounted on automobiles by injection molding of a resin itself without passing through a painting process including painting, coating and the like on the surface of the resin through the expression of excellent surface gloss and metallic feel. More particularly, the present invention relates to a polyamide resin composition comprising an acrylonitrile / 1,3-butadiene / styrene copolymer added to a polyamide resin to improve dimensional stability, to secure mechanical strength by adding an ethylene propylene copolymer grafted with maleic anhydride, Roxy phenyl benzotriazole is added to prevent resin discoloration due to light and heat, and aluminum powder is added to express the metallic feel, so that it is suitable for automobile exterior parts, especially wheel chair. , Low shrinkage, and light weight.

Amide resin, ABS, maleic anhydride, hydroxyphenylbenzotriazole, aluminum powder

Description

TECHNICAL FIELD [0001] The present invention relates to a polyamide resin composition,

The polyamide resin composition according to the present invention is excellent in thermal deformation temperature, shrinkage ratio and strength, and does not cause color discoloration when exposed to the outside, so that it can be applied to an injection molded article itself without being subjected to a coating process. Headphone speaker outer case, and the like, and is particularly used as a material for a wheelchair mounted on an automobile wheel.

In recent years, automobile industry has been emphasizing cost reduction and process simplification not only in terms of high performance of components and high-grade appearance design but also economical aspect. Minimizing the treatment of chemicals such as paint and coating agent is also important in environmental aspect have.

Therefore, each automobile industry encourages the application of plastic inner and outer parts in unpainted areas. However, due to limitations of basic properties such as surface characteristics and strength of plastic resin, application of untreated resin is limited and excellent surface, high dimensional stability, This phenomenon appears to be stronger in the case of the resin for the wheel coverer which requires the characteristic.

Unexamined Japanese Patent Application Laid-Open No. 1997-272783 proposes a non-coating resin composition technique in which a diene rubber is added as an acrylonitrile / 1,3-butadiene / styrene copolymer as a base resin . It has good properties as an unpainted resin due to excellent surface gloss which is advantage of acrylonitrile / 1,3-butadiene / styrene and impact strength reinforced with diene rubber, but acrylonitrile / 1,3-butadiene / styrene copolymer Is inferior in heat resistance to polyamide resin, there is a problem such as shrinkage, warpage and desorption of molded products at high temperature in an automotive wheelchair product requiring a high heat distortion temperature of 150 DEG C or more.

Japanese Patent Application Laid-Open No. 2008-163120 proposes a technique of adding a masterbatch for color expression using a polypropylene resin as a base resin and compensating the mold shrinkage ratio by introducing an inorganic filler. It is possible to secure the mold shrinkage rate by containing surface filler and inorganic filler because of its surface gloss and metal feel through the master batch. However, since the inorganic filler acts as the core of the crack inside the resin, It shows a disadvantage that it is damaged during the driving after mounting.

Korean Patent Laid-Open Nos. 10-2001-0065728 and 10-2001-0109408 disclose polyamide 66 and polyamide 6 as base resin, anhydrous decanedic acid grafting styrene / butadiene copolymer or maleic anhydride grafted ethylene / propylene Although a technique for expressing heat distortion temperature and stiffness suitable for a resin for automobile wheel cover by applying a copolymer has been proposed, there is not proposed a technique for developing a surface gloss and metal feeling, and a resin for preventing discoloration of color There is a disadvantage that it is difficult to apply it without going through a coating process.

The polyamide resin composition according to the present invention has excellent heat distortion temperature, shrinkage ratio and strength, and does not cause color discoloration when exposed to the outside, and is intended to provide an unpainted material that can be applied to an injection molded article itself without being subjected to a coating process.

The present inventors have been studying a material having surface gloss and metal feel with superior rigidity, heat distortion temperature and mold shrinkage ratio than the above conventional unpainted materials and wheel cover materials, and as a base resin, / 1,3-butadiene / styrene copolymer, ethylene propylene copolymer grafted with maleic anhydride, hydroxyphenylbenzotriazole, and aluminum powder are introduced to develop a conventional polyamide resin composition for unpainted materials and automobile wheelers .

The polyamide resin composition of the present invention is excellent in thermal deformation temperature of 150 DEG C or higher, molding shrinkage of 1.2 to 2.0%, tensile strength of 450 to 650 kg / cm < 2 > (L) value of 70 or more, exhibiting a fine surface, metallic feeling, and color discoloration at the time of external exposure, and exhibiting a strength at a low temperature impact strength of 7.0 to 10.0 kg.cm / Value has a characteristic indicating a level of 0 to 3.0.

The present invention relates to a polyamide resin composition comprising 7.0 to 23.0 parts by weight of an acrylonitrile / 1,3-butadiene / styrene copolymer, 14.0 to 25.0 parts by weight of an ethylene / propylene copolymer grafted with maleic anhydride, 0.5 to 2.0 parts by weight of phenylbenzotriazole and 1.5 to 2.5 parts by weight of aluminum powder.

Preferably, the present invention relates to a polyamide resin composition characterized in that the polyamide resin is a compound selected from the group consisting of polyamide 6 and polyamide 66, or a mixture of the two.

The present invention also relates to a polyamide resin composition characterized in that the aluminum powder has a particle size of 30 to 60 탆.

More preferably, the polyamide resin composition of the present invention is a polyamide resin composition comprising tetrakis (methylene (3,5-ditertiarybutyl-4-hydroxyhydrocinnamate)) methane, hindered amine radical scavenger and N- Styrene copolymer and a styrene / styrene / styrene / styrene copolymer.

  The present invention is described in detail as follows.

 1) Polyamide resin

 The polyamide resin to be used in the present invention is not particularly limited, but polyamide 6, polyamide 66, or a mixture thereof may be used. The polyamide 6 and the polyamide 66 may have a relative viscosity of 2.5 to 3.3 (based on a value measured with a 1 g solution of a polymer in 100 ml of 96% sulfuric acid at 20 캜). When the relative viscosity is 2.5 or more, , And excellent dimensional stability can be obtained. In the case of 3.3 or less, it is possible to prevent surface defects and non-molding phenomenon due to a decrease in fluidity.

The polyamide 6 and polyamide 66 having an average degree of polymerization of 200 to 20,000 can be used to improve the mechanical stiffness, dimensional stability, surface properties and heat resistance of the final resin composition.

On the other hand, the polyamide resin of the present invention can be used in the form of a chip for the final resin composition and dried sufficiently in a dehumidifying dryer.

2) acrylonitrile / 1,3-butadiene / styrene copolymer

The resin composition of the present invention is prepared by mixing acrylonitrile, 1,3-butadiene, and styrene copolymer represented by the chemical structure represented by Chemical Formula 1 with polyamide (meth) acrylate in order to secure a mold shrinkage ratio of 1.2 to 2.0% And 7.0 to 23.0 parts by weight based on 100 parts by weight of the resin. The acrylonitrile / 1,3-butadiene / styrene copolymer is contained in the resin composition of the present invention as an amorphous polymer, and serves to delay the crystallization of the resin composition to secure an appropriate molding shrinkage ratio.

If the content is less than 7.0 parts by weight, the effect of improving the molding shrinkage is insignificant, and the molding shrinkage ratio exceeds 2.0%, which causes deterioration during assembly of the injection molded article. When the content exceeds 23.0 parts by weight, And the heat distortion temperature is lowered, so that it is not preferable because it is mounted on an automobile and deformed due to heat generation of the automobile wheel during driving.

3) Ethylene / propylene copolymer grafted with maleic anhydride

The resin composition of the present invention can prevent breakage such as cracking and cracking of the resin molding due to external impact and is suitable for use as an automobile wheeler, which is the main use of the resin composition of the present invention, and has a tensile strength of 450 to 650 kg / In order to achieve strength at a low temperature impact strength of 7.0 to 10.0 kg.cm / cm, an ethylene / propylene copolymer grafted with maleic anhydride represented by the general formula (2) for the purpose of reinforcing strength is added in an amount of 14.0 to 25.0 Parts by weight. The ethylene / propylene copolymer grafted with maleic anhydride has excellent reactivity with the amide group, which is a functional group of the polyamide resin, which is the base resin of the resin composition of the present invention, and thus has an excellent effect of supplementing impact strength as compared with other additives.

R 'is a propylene group.

In order to maximize the effect of the resin composition of the present invention, 14.0 to 25.0 parts by weight of an ethylene / propylene copolymer grafted with maleic anhydride is suitably added to 100 parts by weight of the polyamide resin. If the content is less than 14.0 parts by weight The resin composition does not exhibit sufficient stiffness because the low impact strength measured at -30 deg. C is less than 7.0 kg.cm / cm and the impact strength is insufficiently compensated. When the amount exceeds 25.0 parts by weight, an ethylene / propylene copolymer grafted with maleic anhydride Has a low thermal stability and a high molding shrinkage ratio which affect the resin composition of the present invention and can not meet the object of the present invention in which a heat distortion temperature of 150 DEG C or more and a molding shrinkage ratio of 1.2 to 2.0% , A molding shrinkage ratio exceeding 2.0% was exhibited, and a sharp decrease in flowability was observed, A weld line, a flow mark, or the like is formed on the surface to cause side effects such as poor surface appearance.

4) Hydroxyphenylbenzotriazole

In order to prevent discoloration due to external light or heat after being mounted on an automobile as a resin molding, the resin composition of the present invention is prepared by adding hydroxyphenylbenzotriazole represented by the general formula (3) to 100 parts by weight of a polyamide resin 0.5 to 2.0 parts by weight based on 100 parts by weight of the total composition. Hydroxyphenylbenzotriazole absorbs light energy with weak heat energy and protects the photodegradation of the resin composition due to light. Thus, since the decomposition of the resin composition is prevented, the color change occurs even when the resin molding is exposed to the external environment I will not.

The result of measuring the degree of change of color is represented by ㅿ E value. The value of ㅿ E is calculated by calculating the difference of L, a, b value after the color change from the initial color L, a, b value of the product ² + (initial color a value - color a value at the time of measurement) ² + (initial color b value - color b value at the time of measurement) ² ) (initial color L value - color L value at the time of measurement) represented by ^0.5. In other words, when the E value is measured after a certain time, the larger the value, the larger the color change of the product (resin), and when the E value is 0, the color does not change at all.

In order to maximize the weathering effect of the resin composition of the present invention, 0.5 to 2.0 parts by weight of hydroxyphenylbenzotriazole should be added to 100 parts by weight of the polyamide resin. If it is contained in an amount of less than 0.5 part by weight, the hydroxyphenylbenzotriazole does not have a photodegradation preventing effect on the resin composition. Therefore, the color change value by the accelerated weathering test is more than 3.0, However, if it is contained in an amount exceeding 2.0 parts by weight, discoloration is prevented. However, due to the decomposition of hydroxyphenylbenzotriazole due to its low molecular weight, gas is generated during extrusion molding and injection molding, There are disadvantages.

5) Aluminum powder (Powder)

The resin composition of the present invention is characterized in that it is used in an automobile in a non-coated form without being subjected to a painting process including painting and coating. In order to exhibit color and gloss suitable for such a non- In the resin composition of the present invention, aluminum powder was applied.

The aluminum powder is contained in the resin composition and exhibits metallic feeling and luster. However, since the aluminum powder is not melted differently from the other composition during extrusion and injection molding of the resin, the degree of dispersion and the particle size of the powder affect the molding shrinkage and strength of the resin composition .

Accordingly, the resin composition of the present invention is characterized in that 1.5 to 2.5 parts by weight of aluminum powder having a particle size in the range of 30 to 60 μm is contained per 100 parts by weight of the polyamide resin.

If the particle size of the aluminum powder is less than 30 탆, the particle size is too small to have a sufficient gloss effect. If the aluminum powder has a particle size of more than 60 탆, the dispersibility of the aluminum powder is lowered and the aluminum powder tends to sag, There arises a side effect that different metallic feeling and gloss appear on each part of the surface of the molded article. Even if aluminum powder having a particle size in the range of 30 to 60 占 퐉 is applied, if the content is less than 1.5 parts by weight, the molding shrinkage rate exceeds 2.0%, and the product is detached when the product is molded, And when it exceeds 2.5 parts by weight, the impact strength is lowered so that it is not able to withstand external impacts and is cracked. As a result, the resin composition of the present invention can not be applied to an automobile wheelchair, which is a main component of the resin composition of the present invention. It is preferable that the value of the color (L) is 70 or more with respect to the metallic feeling and the gloss.

6) Others

(Methylene (3,5-ditertiarybutyl-4-hydroxyhydrocinnamate)) methane as a heat stabilizer and a radical scavenger based on a hindered amine as a light stabilizer within the range that does not impair the object of the present invention , And N-phenylmaleimide / styrene copolymer as a compatibilizing agent.

Heat stabilizers are compounds that are mixed with various resins to maintain the physical and chemical properties of the resin during processing and use of the finished product. Since the operations such as mixing and manufacturing plastics are carried out at a high temperature, they are severely decomposed without the protection of additives. PVC, which is used in general purpose plastics for various purposes because it is low in price and excellent in processability, has a weak point in heat, and a heat stabilizer is used to supplement it. The thermal stabilizers are classified into powder, liquid phase, paste, and granule stabilizer according to the form. Cd / Ba / Zn system, Cd / Ba system, Ba / Zn system, Ca / Zn system, Na / , Pb-based, Cd-based, and Zn-based. Depending on the application, it is classified into soft (calendering, pressure extrusion), hard (calendering, extrusion) and heat resistance. In the present invention, tetrakis (methylene (3,5-ditertiarybutyl-4-hydroxyhydrocinnamate)) methane is preferably used.

Light stabilizers are additives to prevent plastics from discoloring from light, especially ultraviolet light, and are often hindered amine radical scavengers.

The compatibilizing agent is added so that it can be effectively mixed when two or more kinds of polymers are mixed. In the present invention, it is preferable to use an N-phenylmaleimide / styrene copolymer.

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

Example  1-10. Preparation of polyamide resin composition

Kneaded in a twin-screw extruder heated to 260 ° C in the composition shown in Table 1 on the basis of 1000 g of the following polyamide resin, dried in a dehumidifying dryer at 95 ° C for 6 hours, Each specimen was prepared at the same temperature as in the melt kneading using a heated screw extruder.

Comparative Example  1-10. Preparation of polyamide resin composition

The composition is the same as the content shown in the following Table 2 when one of the components in the resin composition is out of the range of the present invention.

Test Example . Evaluation of physical properties of the prepared polyamide resin composition

The samples of Examples 1-10 and Comparative Examples 1-10 thus prepared were evaluated in the following physical properties and the results are shown in Tables 3 and 4 below.

1) Tensile strength: A dumbbell-shaped test piece of 3.2 mm in thickness was measured at room temperature using a universal material testing machine according to ASTM D638.

2) Impact strength: According to ASTM D256, a 3.2 mm thick rod specimen was left in a low temperature chamber set at -30 캜 for 3 hours, and Izod Notched impact strength was measured using an impact tester.

3) Thermal deformation temperature: A 6.4 mm thick rod specimen was measured under a load of 4.6 kg / cm 2 using a thermal deformation temperature measuring instrument according to ASTM D648.

4) Molding shrinkage ratio: According to ASTM D955, the mold shrinkage ratio in the resin flow direction was measured using a vernier caliper (Vernier Calipers) for a disk test piece of 3.2 mm thickness.

5) Color (L, b): A test piece for measuring the tensile strength of ASTM D-638 was prepared and the color of the surface of the test piece was measured using a colorimeter.

6) ㅿ E: 3.2 mm thick bar specimens were used for accelerated weathering test using Sunshine Weather-O-Meter, Black Panel temperature 63 ± 3 ℃, rainfall time 12 min / 60 min, nozzle diameter 1.0 mm, nozzle pressure 0.8 (Initial color L value - color L value after lapse of 1500 hours) ² + (initial value of color value after lapse of 1500 hours) by measuring color L, a, Color a value - Color a value after 1500 hours) ² + (Initial color b value - Color b value after 1500 hours) ² ) Color change was measured according to the formula of ^0.5 . In this case, ㅿ E is the vector value of the color change value at the time of measurement as compared with the initial state of the product (resin). If ㅿ E value is larger, the color change is larger as compared with the initial state. It means no at all.

The test results on the physical properties of Example 1-10 are shown to satisfy all of the physical properties to satisfy the object of the present invention as shown in Table 3 above. On the other hand, the test results on the physical properties of Comparative Example 1-10 are as shown in Table 4, where the shaded portions do not satisfy the physical properties required to achieve the object of the present invention. Must be satisfied. In particular, in Comparative Example 10 in which aluminum was not added, the color (L) value was remarkably deteriorated. Therefore, it can be seen that the case of Example 1-10 is superior in physical properties to that of Comparative Example 1-10, thereby achieving the object of the present invention.

As described in detail above, a polyamide resin is used as a base resin and an acrylonitrile / 1,3-butadiene / styrene copolymer, an ethylene / propylene copolymer grafted with maleic anhydride, a hydroxyphenylbenzotriazole, an aluminum powder The added unpainted polyamide resin composition has a problem of lowering the strength and thermal deformation temperature of a resin composition for unpainted applications using polypropylene or an acrylonitrile / 1,3-butadiene / styrene copolymer as a base resin, It is possible to effectively improve the metal feeling and the surface gloss of the resin composition for wheel coverers made of polyamide 6 as a base resin, thereby having an excellent effect, an excellent effect as a resin composition for unpainted use having excellent strength, heat distortion temperature and mold shrinkage ratio, have.

Claims (4)

7.0 to 23.0 parts by weight of an acrylonitrile / 1,3-butadiene / styrene copolymer, 14.0 to 25.0 parts by weight of an ethylene / propylene copolymer grafted with maleic anhydride, 100 parts by weight of a hydroxyphenylbenzotriazole 0.5 to 2.0 parts by weight of a sol and 1.5 to 2.5 parts by weight of an aluminum powder. The method according to claim 1, Wherein the polyamide resin is one kind of compound selected from the group consisting of polyamide 6 and polyamide 66, or a mixture of two kinds. The method according to claim 1, Wherein the aluminum powder has a particle size of 30 to 60 占 퐉. The method according to claim 1, The polyamide resin composition is preferably a copolymer of tetrakis (methylene (3,5-ditertiarybutyl-4-hydroxyhydrocinnamate)) methane, a hindered amine radical scavenger and an N-phenylmaleimide / styrene copolymer Wherein the polyamide resin composition further comprises at least one selected from the group consisting of a polyamide resin and a polyamide resin.