KR100527945B1 - Composition of polyamide nano composite for automobile engine cover and interior/outteior materials with an excellent long-term heat-resistance - Google Patents

Abstract

The present invention relates to a polyamide nanocomposite resin composition for automobile engine covers and interior and exterior materials having excellent long-term heat resistance. More specifically, 0.2 to 5 wt% of hydrotalkit-based long-term heat-resistant agent and nanoclay 2 to polyamide resin 10% by weight, the sum of the phosphite-based heat discoloration inhibitor and the hindered phenolic heat discoloration inhibitor is added by adding 0.3 to 5% by weight, 1.5 to 9% by weight of aluminum powder, 0.5 to 3% by weight of pearl pigment. The present invention relates to a polyamide nanocomposite resin composition for interior and exterior materials that exhibits a metallic feel, such as an engine cover polyamide resin composition, exhibits heat dissipation resistance, flexural strength, and tensile elongation, and has particularly excellent long-term heat resistance. .

Description

Composition of polyamide nano composite for automobile engine cover and interior / outteior materials with an excellent long-term heat-resistance

The present invention relates to a polyamide nanocomposite resin composition for automobile engine cover and interior and exterior materials having excellent long-term heat resistance, and more specifically, to a metallic feel such as a conventional polyamide nanocomposite resin composition for automotive engine covers and interior and exterior materials. The present invention relates to a polyamide nanocomposite resin composition for automobile engine covers and interior and exterior materials, which exhibits excellent appearance, thermal discoloration resistance, flexural strength, tensile elongation, and particularly excellent long-term heat resistance.

In recent years, the business environment of corporations has become increasingly difficult due to the strengthening of regulations and responsibilities. Especially in the current situation where various regulations for environmental protection are being strengthened globally, companies that cannot cope with this have to be seriously concerned about the life and death of companies. It is changing. In particular, the automobile industry is a representative field, and many countries are actively pursuing lightweighting along with alternative energy development. Therefore, many parts such as engine peripheral parts and interior and exterior materials have been replaced by lightweight materials such as plastic, and in recent years, each country has been concentrating its research on developing materials that can maintain the functions of existing products while being lighter. Situation. Therefore, research on the development of a resin that maintains high stiffness while maintaining a low specific gravity, in order to manufacture such a resin composition, nanocomposite manufacturing technology using nano clay having excellent dispersibility has been applied in recent years. have.

The nanocomposite manufacturing technology using nanoclay is an industrial-based technology that has undergone basic research in the 80's and 90's, and is now in the commercialization stage in western developed countries including the United States and Japan. This technology involves the concept of exfoliating the silicate layered clay mineral to nanoscale size and dispersing it in the polymer resin to raise the limit of low mechanical properties of the general purpose polymer to the engineering plastic level. Plate silicates, the basic unit of clay minerals, are very difficult to peel and disperse in polymer resins due to the strong van der Waals attraction.The low molecular weight organizing agent is intercalated between the silicate layered structures to facilitate the penetration of polymer resins. It is a technique of peeling and dispersing. In other words, the conventional inorganic fillers are dispersed in a polymer resin with a particle size of 1 μm or more, dispersed to nanoscale, and aims to supplement the shortcomings of the conventional inorganic filler composites. The research and development of new materials in the 21st century through the development of thermoplastic resins, elastomers, and coatings that have enhanced strength and stiffness, gas / liquid permeability, flame resistance, abrasion resistance, and high temperature stability without compromising the impact resistance, toughness and transparency of polymer resins. There is a focus. Therefore, it is a key technology that can make a significant change in the market of composite production market of the 21st century in a very advantageous way in terms of performance and cost.

Patents for such a technique include Japanese Patent Application Laid-Open No. 76-109998, Japanese Patent Application Laid-open No. Hei 2-190432, Japanese Patent Application Laid-Open No. 4-178459, Japanese Patent Application Laid-Open No. 9-48908, Japanese Patent Application Laid-open No. Hei 11-335408 There are many domestic and foreign patents, including 4,739,007, U.S. Patent 4,810,734, U.S. Patent 4,874,728, U.S. Patent 5,910,523. However, the patents do not apply to the engine cover and interior and exterior moldings of automobiles that require a metallic feel, heat dissipation prevention and long-term heat resistance, which require the appearance quality of the molding and the heat dissipation prevention and long-term heat resistance.

In order to improve the quality of the moldings, there is a method of imparting a metallic feeling, such as dispersing aluminum powder or the like on a resin or varnish and then coating the molded product; and adding aluminum powder or the like directly to the resin. The coating method has a disadvantage in that many organic solvents are used in the coating process, and a lot of money is spent on equipment investments such as facilities and places for washing and drying them, and problems of environmental pollution by organic solvents occur. For example, Japanese Patent Application Laid-open No. 5-93091 has a patent which is characterized by adding aluminum powder or the like directly to the resin to give a metallic feeling to the molding, but has a disadvantage of preventing heat discoloration and long-term heat resistance, and preventing heat discoloration. In order to improve the properties, European Patent No. 022 313 has a patent which is characterized by simultaneously expressing metallic feeling and heat discoloration resistance by adding various antioxidants, but has a disadvantage in that long-term heat resistance is insufficient.

Accordingly, the inventors of the present invention have an object of providing a resin composition supplementing the long-term heat resistance of the conventional polyamide nanocomposite resin composition for automobile engine cover and interior and exterior materials by applying a hydrotalkit-based long-term heat-resistant agent.

In addition, the present invention is excellent in addition to the addition of a hydrotalkit-based long-term heat-resistant agent while expressing the metallic feel and heat discoloration prevention properties of the conventional polyamide nanocomposite resin composition for automobile engine cover and interior and exterior materials equal or more Another object of the present invention is to provide a polyamide nanocomposite resin composition for automobile engine cover and interior and exterior materials which is endowed with long-term heat resistance.

The present invention relates to 76 to 87% by weight of a polyamide resin base polymer, 0.2 to 5% by weight of a hydrotalkyd long-term heat-resistant agent; 2-10 wt% of nanoclays; The sum of the phosphite thermal discoloration inhibitor and the hindered phenolic thermal discoloration inhibitor is 0.3 to 5% by weight; Aluminum powder 1.5-9 wt%; And a polyamide nanocomposite resin composition for an engine cover and an interior and exterior material including 0.5 to 3% by weight of a pearl pigment. The present invention will be described in more detail as follows.

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Polyamide resin used in the present invention is a resin that is excellent in stiffness, toughness, wear resistance, chemical resistance, reinforcing agent, etc. compared to various engineering plastics applied to automobiles as a resin widely applied to engine peripheral parts and interior and exterior parts In the present invention, the polyamide resin is not particularly limited.

Preferably a polyamide 6 resin having a relative viscosity of 1.5 to 3.0 (1 g solution of polymer in 100 ml of 96% sulfuric acid) or a relative viscosity of 1.5 to 3.0 (1 g solution of polymer in 100 ml of 96% sulfuric acid at 20 ° C). Polyamide 66 can be used, but in order to reduce manufacturing costs, polyamide 6 resin is more preferable. If the viscosity of the polyamide resin to be used is less than the above range, the fluidity of the composition is improved to improve the appearance of the molded product, but the mechanical and thermal properties are deteriorated. There is a disadvantage in that a molding problem, such as occurs.

Hydrotalkit-based long-term heat-resistant agent used as an additive for imparting long-term heat resistance to the resin composition in the present invention is composed of an inorganic chemical molecular structure represented by the following formula (1).

M _(1-x) M ' _x (OH) ₂ A ^n- _{x / n} .mH ₂ O

(Wherein M and M 'are divalent and trivalent metal cations, respectively)

x must satisfy 0 <x <0.5,

m is 0 ≤ m ≤ 4,

An- is anion with a valence of n.)

Preferably M is magnesium and M 'is aluminum.

The hydrotalkit-based thermal stabilizer of Formula 1 can maintain a stable structure even at a high temperature for a long time compared to a conventional thermal stabilizer to stably maintain the hydrogen peroxide component which is a core decomposition agent in the decomposition mechanism of various thermoplastic resins by heat or light. Excellent ability to adsorb. The usable content is 0.2 to 5% by weight of the total resin composition, if the content is less than 0.2% by weight long-term heat resistance is insufficient, when the content exceeds 5% by weight has a disadvantage in that the tensile elongation falls.

In addition, in the present invention, the nanoclay added to improve the flexural strength of the resin composition has a clay surface comprising a cationic head group and a lipophilic tail group to enhance affinity with polyamide. Various organicizing agents can be added. Alkylamine types such as, for example, propylamine, butylamine, octylamine, decylamine, dodecylamine, hexadecylamine, octadecylamine, N-methyloctadecylamine; Methylamine hydrochloride, tetramethylammonium chloride, octadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, dioctadecyldimethylammonium bromide, dimethylbenzyloctadecylammonium bromide, bis (2-hydroxylethyl) methyl Alkylammonium halide types such as octadecyl ammonium chloride, 1-hexadecylpyridium bromide; Alkylaminoacid types such as 6-aminohexanoic acid and 12-aminododecanoic acid; There are alkyldiamine types such as 1, 6-hexamethylenediamine, 1, 12-dodecanediamine. Preferably, it is preferable to use nanoclays whose surface is modified with an alkylating agent of the alkyl ammonium halide type. The content of such nanoclays is 2 to 10% by weight of the total resin composition, if the content is less than 2% by weight, there is a disadvantage that the flexural strength is lowered, if more than 10% by weight there is a disadvantage that the tensile elongation is sharply lowered do.

In addition, in the present invention, the thermal discoloration inhibitor added to prevent discoloration by heat of the resin composition may be generally applied to three kinds of heat-resistant agents, respectively, or a combination thereof. Hindered phenolic system which is a primary heat resistant agent; Phosphite based secondary heat-resistant agent; Thioether type; The inorganic heat resistant agent may be divided into a copper halide heat resistant agent and the like. Preferably, the hindered phenolic heat resistant agent and the phosphite heat resistant agent are mixed in a ratio of 1: 2 to 1: 3. When the heat resistant agent is added to 0.3 to 5% by weight of the total resin composition, it is effective to prevent the heat discoloration of the resin composition, when the content of the heat discoloration inhibitor is less than 0.3% by weight, the heat discoloration prevention property is lowered and exceeds 5% by weight. There is a disadvantage that the tensile elongation falls.

In addition, in the present invention, in order to give a metallic feeling to the resin composition, aluminum powder and pearl pigment are added. The aluminum powder is a pulverized metal aluminum ball mill or the like, the particle size is 10 ~ 100 micrometers, the aspect ratio is preferably 5 ~ 3000, and the pearl pigment as a pigment that is a titanium treated fine mica surface having a laminated structure. It is preferable that a particle diameter is 10-100 micrometers, and an aspect ratio is 5-500. In order to facilitate the addition of these aluminum powders and pearl pigments, a pigment master batch containing a high concentration of these additives is prepared by using low viscosity polyamide 6 as a binder and added to prepare the resin composition of the present invention. It is preferable. The usable content is preferably from 1.5 to 9% by weight of the aluminum powder in the total resin composition and from 0.5 to 3% by weight of the pearl pigment. If the content is less than the above-mentioned range of each component, the metallic feeling is insufficient and the content may be exceeded. In this case, there is a disadvantage that the tensile elongation falls.

The extruder used to manufacture the polyamide nanocomposite resin composition for the engine cover and the interior and exterior materials of an automobile having excellent long-term heat resistance of the present invention having such a composition includes a twin screw extruder, and the cylinder barrel temperature is 275 ° C. To 285 ° C (245 ° C to 265 ° C for polyamide 6), in order to maximize the physical properties of the resin composition in the primary inlet using two extruders extruded polyamide resin, heat stabilizer, thermochromic It is preferable to mix | blend an inhibitor, an aluminum powder, and a pearl pigment, after mixing uniformly, and to introduce a nano gray into a secondary inlet. In addition, in order to maximize the physical properties of the composition during melt kneading, it is desirable to minimize the residence time, and to install a decompression device called vent (Vent) near the discharge portion to reduce the pressure to 150 mmHg or less gas phase low molecular material generated during melt kneading It is effective to remove it.

In addition, a conventional mold release agent, a weathering agent, a pigment, various organic or inorganic fillers, etc. can be added as needed within the range which does not violate the objective of this invention.

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

Examples 1-11 and Comparative Examples 1-11

The compositions and contents as shown in Table 1 were melt kneaded in a twin screw extruder heated at 260 and then made into chips and dried using a dehumidifying dryer for 90 hours for 5 hours. The composition used at this time is as follows.

(1) Polyamide 6: relative viscosity 2.5

(2) Long-term heat resistant agent: hydrotalkit-based inorganic heat stabilizer [trade name: DHT-4A "of Kyowa Products of Japan]

(3) Nanoclays: Cray surface modified with an alkylating agent of the alkylammonium halide type [trade name "Cloisite 93A, of Southern Clay Product, USA"

(4) Thermochromic inhibitor-1: Hindered phenolic thermochromic agent [trade name Irganox 1010 "of CIBA GEIGY of Switzerland]

(5) Heat discoloration inhibitor-2: Phosphite type heat discoloration inhibitor [trade name ADK STAB PEP-36 "of the Japan ASAHI DENKA Corporation.

(6) Metallic master batch: 40 wt% of polyamide 6 having a relative viscosity of 2.0 to 45 wt% of aluminum powder manufactured by Sumitomo Color, Japan, EPC-8E-340 ", 15 wt% of" Iriodin 100 ", which is a pearl pigment from MERCK, Germany Resin composition prepared by melt kneading

Composition (% by weight) Polyamide 6 Long-term heat resistant Nanoclay Thermochromic Agent-1 Thermochromic Agent-2 Metallic Masterbatch Example One 81 2 5 One One 10 2 82.5 0.5 5 One One 10 3 79 4 5 One One 10 4 83 2 3 One One 10 5 87 2 9 One One 10 6 81.8 2 5 0.2 One 10 7 80.2 2 5 1.8 One 10 8 81.6 2 5 One 0.4 10 9 79.5 2 5 One 2.5 10 10 84 2 5 One One 7 11 76 2 5 One One 15 Comparative example One 83 0 5 One One 10 2 75 8 5 One One 10 3 85.5 2 0.5 One One 10 4 71 2 15 One One 10 5 83 2 5 0 0 10 6 82.9 2 5 0 One 10 7 76 2 5 4 One 10 8 82.9 2 5 One 0 10 9 77 2 5 One 5 10 10 89 2 5 One One 2 11 61 2 5 One One 30

Test Example

In order to measure the physical properties of the compositions obtained in the above Examples and Comparative Examples, each specimen was manufactured at the same temperature as melt kneading by using a heated screw injection machine, and evaluated using the following evaluation method. It is shown in Table 2 below.

(1) Long-term heat resistance: After making 1/8 inch debel type specimen used for tensile elongation, and leaving it in an oven maintaining a constant temperature at 130 ° C for 400 hours, the tensile elongation measurement speed was 50mm according to ASTM D638. Measured by setting / minute.

(2) Thermochromic: A specimen consisting of 50mm in width, 70mm in length, and 2mm in thickness was fabricated, and it was used as a color difference meter [model name: chroma meter CR-200] of Minolta, Japan. After measuring the a and b values, the same specimen was aged in an oven maintaining a constant temperature at 130 ° C. for 400 hours, and the L, a, b values of the specimen were measured again. The color difference value (ΔE) before and after standing in a high temperature oven is measured.

ΔE = (ΔL2 + Δa2 + Δb2)

ΔL = (L value of the specimen after aging)-(L value of the specimen before aging)

A = (a value of the specimen after aging)-(a value of the specimen before aging)

B = (b value of the specimen after aging)-(b value of the specimen before aging)

(3) Metallic appearance: A specimen consisting of 50 mm in width, 70 mm in length, and 2 mm in thickness was fabricated and evaluated by visually dividing the external appearance of the specimen and the degree of dispersion of each component under the fluorescent lamp at all angles.

◎: A lot of light is reflected from the surface of the specimen and each component is uniformly dispersed

(Triangle | delta): The light reflected from the specimen surface and the dispersion degree of each component are average levels.

X: little light is reflected from the surface of the specimen, and the degree of dispersion of each component is also uneven.

(4) Tensile Elongation: Measured by setting tensile elongation measuring speed to 50 mm / min after fabricating 1/8 inch dembbell specimen in accordance with ASTM D638.

(5) Flexural strength: measured by making 1/8 inch specimens in accordance with ASTM D790

Properties Long term heat resistance (%) Thermochromic (△ E) Metallic exterior Tensile Elongation (%) Flexural Strength (㎏ / ㎠) Example One 12 4 ◎ 15 1400 2 13 4 ◎ 18 1380 3 13 4 ◎ 14 1430 4 15 3.5 ◎ 18 1300 5 11 4.5 ◎ 12 1750 6 11.5 4.8 ◎ 16 1440 7 13.5 2.9 ◎ 15 1370 8 11 4.5 ◎ 16 1425 9 13 2.4 ◎ 16 1350 10 14 4.2 ◎ 17 1360 11 11 3.8 ◎ 13 1520 Comparative example One 2.2 5 △ 17 1375 2 4.1 3.8 ◎ 4.5 1440 3 15 3.6 △ 38 900 4 2.2 4.9 ◎ 2.5 2300 5 8 40 △ 17 1430 6 14 15 △ 17 1420 7 4 3.5 ◎ 5 1370 8 10 25 △ 17 1420 9 3.5 1.9 ◎ 4 1360 10 14 4.7 × 19 1330 11 4.3 3.8 △ 4.7 1700

As shown in Table 2, the composition of the embodiment according to the present invention has excellent long-term heat resistance of 8-20%, thermochromic 2-6, tensile elongation 8-25%, flexural strength 1,200-1,900 kg / cm ² , etc. It could be confirmed that it had a metallic appearance.

As described in detail above, according to the present invention, by adding a hydrotalkit-based inorganic heat stabilizer, which is a long-term heat-resistant agent, thermal discoloration prevention and metallic properties such as polyamide nanocomposite resin compositions for automobile engine covers and interior and exterior materials Although the appearance, tensile elongation, and flexural strength that give a feeling were expressed, long-term heat resistance was particularly excellent.

Claims (5)

76 to 87% by weight of a polyamide resin base polymer, 0.2-5% by weight of hydrotalkyd based long-term heat resistant agent; 2-10 wt% of nanoclays; The sum of the phosphite thermal discoloration inhibitor and the hindered phenolic thermal discoloration inhibitor is 0.3 to 5% by weight; Aluminum powder 1.5-9 wt%; And Pearl pigment 0.5-3 wt% Polyamide nanocomposite resin composition for an engine cover and interior and exterior materials comprising a. The method of claim 1, wherein the polyamide resin is a polyamide 6 resin having a relative viscosity of 1.5 to 3.0 (20 ° C, 1 g of a polymer in 100 ml of 96% sulfuric acid) polyamide resin for the vehicle engine cover and interior and exterior materials Amide nanocomposite resin composition. The polyamide nanocomposite resin composition for automobile engine cover and interior and exterior materials according to claim 1, wherein the long-term heat-resistant agent is a hydrotalkit-based inorganic heat stabilizer represented by Chemical Formula 1. Formula 1 Mg _(1-x) Al _x (OH) ₂ A ^n- _{x / n} .mH ₂ O (Wherein M and M 'are divalent and trivalent metal cations, respectively) x must satisfy 0 <x <0.5, m is 0 ≤ m ≤ 4, An- is anion with a valence of n.) The polyamide nanocomposite resin composition according to claim 1, wherein the nanoclay is an alkylating agent of the alkyl ammonium halide type, and is a clay having a modified surface. The polyamide nanocomposite resin composition for automobile engine cover and interior and exterior materials according to claim 1, wherein the heat discoloration preventing agent is a hindered phenolic heat resistant agent and a phosphite heat resistant agent.