KR20130078774A

KR20130078774A - Polyamide resin composition

Info

Publication number: KR20130078774A
Application number: KR1020110147893A
Authority: KR
Inventors: 박수연; 박지혁; 김창규
Original assignee: 코오롱플라스틱 주식회사
Priority date: 2011-12-30
Filing date: 2011-12-30
Publication date: 2013-07-10

Abstract

The present invention relates to a polyamide resin composition, more specifically, 75.9 to 54% by weight of a polyamide resin; Glass fiber 24 to 45% by weight; And a heat resistant agent containing 0.1 to 1 wt% of a metal halide heat resistant agent and a HALS (Hindered Amined Light Stabilizer) heat resistant agent, and relates to a polyamide resin composition having improved calcium chloride and internal copper liquid properties.

Description

Polyamide resin composition {POLYAMIDE RESIN COMPOSITION}

The present invention relates to a polyamide resin composition that can be used as a material for a radiator head tank.

In the conventional automobile radiator head tank production, a resin composition in which glass fibers reinforced with polyamide 66 resin were reinforced by a process of injection molding was prepared in order to enhance mechanical strength. In addition, it is mainly used for small cars and obtained by one product out of one mold. However, recent advances in this field have been applied to not only small cars but also medium / large passenger cars and commercial vehicles. I get a product by (cavity).

As a result of this change in manufacturing method, it is difficult to flow the resin due to poor fluidity during injection into a conventional composition for manufacturing a large number of cavity molds and large radiator head tanks. There is a problem in that the glass fiber is biased, thereby causing a fine crack phenomenon on the surface to degrade the physical properties to cause leakage of the cooling water when used for a long time. Therefore, in order to apply the plastic material of the radiator head tank to the plastic, the mechanical durability, that is, the strength and stiffness according to the replacement of the existing metal material must be satisfactory, and the impact resistance and vibration resistance according to the driving of the car must also be sufficiently considered. In addition, since it is a material used in the engine system, it is necessary to have an excellent level of stability against chemicals of antifreeze and calcium chloride, and an appropriate level of heat resistance and strength that can withstand a long time in a high temperature environment of the engine part.

Especially for radiator head tanks made of plastic without internal fluid and calcium chloride resistance, internal cracks may occur due to prolonged contact with antifreeze and contact with calcium chloride, which is most commonly used as a snow removal chemical in winter. do. This can be said to be an essential characteristic for automobile parts that are directly connected to human life.

In order to solve this problem, Japanese Patent Laid-Open No. 1193359 discloses 55 to 25 parts by weight of polyamide 6 (relative viscosity 2.2 to 3.0) and 25 to 50 parts by weight of polyamide 66 (relative viscosity 2.2 to 3.0).

The method of improving the fluidity and improving the surface by adding parts by weight is disclosed. However, since the content of polyamide 6 is higher than that of polyamide 66, the hydrolysis and heat resistance characteristics, which are important characteristics of the radiator head tank, are reduced. The disadvantage is that. In addition, US Patent No. 488764, Japanese Patent Publication Nos. 60-86162 and 60-179455 disclose resin compositions composed of polyamides and polyolefins, but have excellent rigidity, flowability, and dimensional stability, but lack of heat resistance. In addition, in order to improve the hydrolysis resistance of polyamide, US Pat. No. 4,448,386 is a method of blending polyamide and ethylene-propylene rubber grafted with maleic anhydride, and US Pat. Processes for blending ethylene-propylene diene rubbers are disclosed, respectively, but result in poor heat resistance and flowability. Therefore, the composition prepared by such a method is undesirable because it is applied to a large product or a complex structure, for example, automotive engine cover, radiator head tanks, etc., resulting in poor molding and surface defects.

On the other hand, as a method for improving the mechanical properties of the polymer resin, a technique for adding an inorganic material is widely used. Representative inorganic materials include glass fiber or so-called mineral, and it is known that reinforcing glass fiber alone is more effective in terms of mechanical properties. When the glass fiber is added to the resin, the rigidity, heat resistance, oil resistance, etc. of the resin are excellent, but the impact resistance is poor, and the surface characteristics of the final product are poor. Therefore, a method of increasing the molding temperature and mold temperature or increasing the injection speed during injection molding is used, but this method is not only disadvantageous in terms of processing molding but also causes a decrease in productivity, which is not preferable. Reinforcing the glass fiber is excellent in strength and heat resistance, but there is a problem in that the anisotropy that causes bending / deformation is increased. Therefore, in order to improve this, a technique of reducing the deformation of the molding by introducing a so-called hybrid composite reinforcement method, which is added by reinforcing glass fiber and minerals together, has been developed, but this method is also undesirable because it causes surface defects of the molded product. .

U.S. Patent No. 3843591 improves the interfacial adhesion between inorganic and inorganic materials.

A method of improving the physical properties of the composition has been proposed and Japanese Patent Laid-Open No. 58-17440 refers to the improvement of surface properties. However, the composition according to the US patent has a disadvantage in that the coupling agent introduction effect is excellent but the manufacturing cost increases in processing, and the composition according to the Japanese patent has the disadvantage that the introduction of alkaline earth metal lowers the rigidity of the final product.

In addition, Japanese Patent Laid-Open No. 59-133249 introduced a technique of adding glass fiber and a plasticizer to improve flowability, but there is a problem in that moldability and impact strength are excellent but rigidity is lowered according to the addition of the plasticizer.

The present invention is to provide a composition that can be applied to the radiator head tank material because the weight of the product can be made by a light and simple process, and also excellent in fluidity and surface properties, excellent internal fluid and calcium chloride resistance polyamide It is intended to provide a resin composition.

Accordingly, the present invention provides a preferred embodiment, the polyamide resin 75.9 ~ 54% by weight; Glass fiber 24 to 45% by weight; And it provides a polyamide resin composition comprising 0.1 to 1% by weight of a heat resistant agent comprising a metal halide heat resistant agent and a HALS (Hindered Amined Light Stabilizer) heat agent.

The polyamide resin according to the embodiment may be polyamide 66.

The polyamide resin composition according to the embodiment may be one having a tensile strength of 500kg / cm ² or more and a flexural strength of 1,000kg / cm ² or more, based on ASTM D638, measured according to the following internal copper solution evaluation method.

Evaluation of Internal Copper Elution: After dipping tensile / flex specimens in a mixed solution of distilled water / antifreeze = 55/4, and using an autoclave, it was left for 144 hours at 2 atm and 146 ° C, followed by a universal testing machine (Instron). Tensile strength and flexural strength were evaluated.

The polyamide resin composition according to the embodiment may be one having a tensile strength of 1,000kg / cm ² or more and a flexural strength of 1,500kg / cm ² or more based on ASTM D638, measured according to the following evaluation method of calcium chloride resistance.

Calcium chloride resistance evaluation method: After distilled water / CaCl ₂ 5.5vol% mixed solution, the tensile / flex specimens were immersed in an airtight container, followed by a total of 33 cycles aging for 2 hours at 100 ° C and 1 hour at room temperature. Evaluate strength.

The polyamide resin composition according to the present invention can be used as an automobile radiator head tank application material because the surface characteristics satisfy the required level suitable for automobile radiator head tanks, and in particular, it has excellent internal fluid and calcium chloride resistance.

Hereinafter, the present invention will be described in more detail.

The present invention is polyamide resin 75.9 ~ 54% by weight; Glass fiber 24 to 45% by weight; And it relates to a polyamide resin composition comprising 0.1 to 1% by weight of a heat resistant agent comprising a metal halide heat resistant agent and a HALS (Hindered Amined Light Stabilizer) heat agent.

The polyamide resin preferably used in the present invention is polyamide 66, which may be represented by the following formula (I).

Formula I

O

-(NH- (CH2) 6-NH-C- (CH2) 4-C) n-

Where n is an integer from 200 to 15,000

Polyamide 66 resin can be prepared according to conventional methods. An example of a typical method is as follows. Hexamethylenediamine, a polyamide polymerization raw material, in a polyamide resin polymerization autoclave equipped with a stirrer, heat sensor, temperature controller, and steam reflux

Depending on the adipate salt (hereinafter referred to as "AH salt") and the concentration of this AH salt,

It is added and stirred while raising the temperature to dissolve uniformly. Subsequently, in a separate container, various additives are dispersed in a mixed solvent of methanol and water to prepare a uniform slurry, and then, the AH salt is dissolved in a reaction tube where polyamide 66 having the necessary properties according to a conventional polyamide 66 manufacturing process is prepared. It can manufacture. In addition to the raw materials, a small amount of hexamethylene diamine, an antifoaming agent, and the like can be additionally added by excessively adding acetic acid as a viscosity stabilizer. After all the raw materials are introduced into the reaction tube, oxygen is removed while purging high-purity nitrogen gas. The desired polyamide 66 resin can be obtained. The production process of such polyamide 66 is summarized as follows.

Manufacturing stage Pressure (kg / cm2) Temperature (℃) Time (min) Temperature rise Normal pressure-> 17.5 120-> 230 60 Suppression 17.5 Maintenance 230-> 255 80 Decompression 17.5-> normal pressure 255-> 270 70 maintain Atmospheric pressure 270-> 275 30 Discharge Atmospheric pressure-> 2.5 275-> 280 20

In the step of increasing the temperature and pressure during the manufacturing process of the polyamide 66 as described above, as the temperature is increased, the steam is filled in the autoclave, thereby increasing the pressure. At this time, it heats to 230 degreeC over 60 minutes from when temperature became 120 degreeC. When the pressure reaches 17.5kg / cm ² , steam is discharged to the outside to maintain the pressure and raise the temperature to 250 ° C. The pressure is dropped to the normal pressure for 70 minutes while flowing out to the outside again, maintained for 30 minutes, stabilized, and then discharged by adding 2 to 2.5 kg / cm 2 of nitrogen to prepare a polyamide 66 resin suitable for the present invention.

In order to manufacture the final resin composition suitable for this invention, the polyamide 66 resin obtained by the above-mentioned method is preferable to dry at 90 degreeC for 5 hours in a dehumidification type dryer. The polyamide 66 resin suitably used in the present invention is that of a relative viscosity of 2.5 to 3.5 (1 g solution of polyamide 66 resin in 100 ml of 20 ° C 96% sulfuric acid). If the viscosity of the polyamide 66 resin to be used is less than the lower limit of the above range may lead to a decrease in impact resistance, and if the viscosity exceeds the upper limit, surface manifestation of the glass fiber occurs due to poor fluidity.

In order to express the improvement of surface properties and stiffness, internal copper solution and calcium chloride resistance in the present invention, since the internal molecular structure can be expressed as a rigid binding force between the resin and the inorganic additive, the conventional general glass to increase the binding force between the resin and the inorganic interface Glass fibers imposed with calcium chloride properties in the inner copper fluid different from the fibers were used. The glass fiber used is a glass fiber called G or K glass, which contains CaO, SiO2, and Al2O3 as main components, and typically contains 10 to 20% by weight of CaO, 50 to 70% by weight of SiO2, and 2 to 15% by weight of Al2O3. have. Glass fiber used in the present invention has a diameter of 10 ~ 13um and a length of 2.7 to 3.5mm, the surface is treated with silane (coupling agent) and 262H is treated with a sizing agent to increase the internal fluid and calcium chloride resistance (Brand name, manufacturer: NEG company (Japan)) was used. The coupling treatment agent is a silane-based material having an organic functional group such as a vinyl group, an epoxy group, a mercaptan group, an amine group, or a urethane group, and the sizing agent preferably uses a sizing agent such as urethane, epoxy, polyvinyl acrylate, etc. .

In the present invention, the glass fiber is added in an amount of 25 to 45 wt% based on 100 wt% of the total composition. If it is less than 25% by weight, the stiffening effect is insignificant, and if it exceeds 45% by weight, there is a concern that processing problems may occur.

The metal halide-based and HALS-based heat-resistant agents are added to the composition of the present invention to impart thermal stability. The heat resistant agent has no effect on the short-term heat resistance, which is expressed as the heat deformation temperature when added to the resin composition, but brings about heat stabilization of the product used at high temperature for a long time, which can be understood in the same context as durability in molded products. The heat resistant agent used in the present invention may be exemplified by couprus iodide, potassium iodide and the like as the metal halide heat resistant agent. Rowanox HD98, a 3,3-bis (3,5-ditertbutyl-4-hydroxyphenyl-N-N'-hexamethylenebispropionamide having a HALS-based amide group in such a metal halide heat-resistant agent It is particularly preferable that the total amount added by mixing the company: Chemtura is 0.1 to 1% by weight based on 100% by weight of the total composition.

If the amount of the heat-resistant agent is less than 0.1% by weight, the effect of addition is insignificant, and if it is more than 1% by weight, the enhancement of the effect of addition is not so great, but the manufacturing cost increases, which is not preferable.

In the composition of the present invention, a releasing agent, a coloring agent, and the like can be selectively added to suit the purpose and purpose of the final product within the scope not impairing the object of the present invention in addition to the essential components.

Each component of this invention can produce the polyamide resin composition of this invention by extruding using an extruder. The mixer may be prepared by kneading at 275 ° C. to 285 ° C. using a twin screw extruder. In order to maximize the kneading of the resin composition, a polyamide resin and a heat-resistant agent are added to the primary inlet by using an extruder having three inlets. It is preferable to inject glass fiber into the secondary inlet. In addition, it is desirable to minimize the residence time in order to prevent thermal decomposition of the composition during melt kneading, and the optimum seek speed adjustment is necessary in consideration of the dispersibility in the present composition, and a rotation speed of about 200 to 300 rpm is appropriate.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. The present invention is not limited by the Examples.

Examples 1 to 3 and Comparative Examples 1 to 10

After melt-kneading in a twin screw extruder heated to 280 ℃ according to the composition shown in Table 2 and dried in a chip state at 90 ℃ for 5 hours using a dehumidifying dryer to the same temperature as melt kneading using a heated screw injection machine Each specimen was fabricated and evaluated by the same measurement method, and the results are shown in Table 3.

The physical properties of the polyamide resin compositions prepared in Examples and Comparative Examples were evaluated based on the following evaluation methods.

1) Tensile strength: Tensile specimens were prepared according to ASTM D638 and measured.

2) Flexural strength: 1/8 inch specimens were measured according to ASTM D790.

3) Internal Copper Liquid: After dipping tensile / flex specimens in a mixed solution of distilled water / antifreeze = 55/45, and using an autoclave, it was left for 144 hours under conditions of 2 atm and 146 ℃, followed by a universal material tester (Instron). Tensile strength and flexural strength were evaluated.

4) Calcium Chloride Resistance: Tensile / flex specimens were immersed in a sealed container of 5.5 vol% distilled water / CaCl2 in a sealed container, followed by tensile cycle and flexural strength after a total of 33 cycles at 100 ° C * 2 hours and room temperature * 1 hour. Was evaluated.

5) Heat resistance: Tensile strength was evaluated after aging in UL oven at 140 ℃ for 1000 hours.

6) Surface characteristics: After drying the resin composition of the present invention made by melting and kneading in a chip state at 90 ° C. for 5 hours using a dehumidifying dryer, a 150 ton injection molding machine manufactured by Nisei, having a diameter of 10 cm and a thickness of Using a 3.2mm disc mold, the molded product was fixed at an injection temperature of 275 ℃ and a mold temperature of 40 ℃, and then the molded products released under the injection pressure of 800kg / cm2 and no holding pressure were visually observed.

★★: Surface condition is very good

★: Good surface condition

☆: Poor surface condition

☆☆: Surface condition is very bad

division Polyamide 66
(weight%) Fiberglass
(weight%) Heat Resistant (wt%) Metal halide system + HALS system Example 1 66.9 33 0.1 Example 2 66 33 One Example 3 64 33 3 Comparative Example 4 74.9 20 0.1 Comparative Example 5 72 20 3 Comparative Example 6 61.9 38 0.1 Comparative Example 7 59 38 3 Comparative Example 8 54.9 45 0.1 Comparative Example 9 52 45 3 Comparative Example 10 47 50 3

Polyamide 66: Pensacola 50 BWFS

Fiberglass: NEG, 262H

Metal halide heat-resistant: Brugman, H320

HALS type heat resistant agent: Chemtura, HD98

division
After antifreeze deposition After calcium chloride deposition After heat test
Surface properties
The tensile strength
(kg / cm2) Flexural strength
(kg / cm2) The tensile strength
(kg / cm2) Flexural strength
(kg / cm2) The tensile strength
(kg / cm2) Example 1 520 1,200 1,130 1,650 1830 ★★ Example 2 535 1,300 1,180 1,730 2130 ★★ Example 3 540 1,300 1,165 1,750 2200 ★ Comparative Example 4 430 980 970 1,210 1540 ★★ Comparative Example 5 445 1,050 990 1,300 1680 ★★ Comparative Example 6 540 1,180 1,250 1,710 1940 ☆☆ Comparative Example 7 550 1,200 1,300 1,720 2310 ☆☆ Comparative Example 8 570 1,300 1,320 1,810 1980 ☆☆ Comparative Example 9 585 1,250 1,400 1,850 2340 ☆☆ Comparative Example 10 600 1,450 1,505 1,870 2410 ☆☆

As can be seen from the evaluation results of the physical properties of the test pieces prepared from the resin compositions according to the above Examples and Comparative Examples, the polyamide resin composition of the present invention was surface-coated with aminosilane and glass fiber sized with urethane and polyvinylacetate. The stiffness and heat resistance chemical properties were improved by using.

Therefore, the composition of the present invention can be used as a vehicle radiator head tank application material because the surface properties satisfy the required level, in particular, excellent in internal fluid and calcium chloride resistance.

Although the present invention has been described in detail with reference to the above embodiments, it should be understood that substitutions, changes and modifications apparent to those skilled in the art within the scope of the present invention fall within the scope of the present invention.

Claims

75.9 to 54% by weight polyamide resin, 24 to 45% by weight glass fibers; And
A polyamide resin composition comprising 0.1 to 1% by weight of a heat resistant agent comprising a metal halide heat resistant agent and a HALS (Hindered Amined Light Stabilizer) heat resistant agent.

The method of claim 1,
The polyamide resin is a polyamide resin composition, characterized in that the polyamide 66.

The method of claim 1,
To within the anti-freeze property evaluation of tensile strength 500kg / cm ² or more and a flexural strength The polyamide resin composition according to claim 1,000kg / cm ² less than that based on the, ASTM D638, measured according to.
Evaluation of Internal Copper Elution: After dipping tensile / flex specimens in a mixed solution of distilled water / antifreeze = 55/4, and using an autoclave, it was left for 144 hours at 2 atm and 146 ° C, followed by a universal testing machine (Instron). Tensile strength and flexural strength were evaluated.

The method of claim 1,
Polyamide resin composition characterized in that the tensile strength of 1,000kg / cm ² or more and the flexural strength of 1,500kg / cm ² or more based on ASTM D638, measured according to the calcium chloride resistance evaluation method.
Calcium chloride resistance evaluation method: After distilled water / CaCl ₂ 5.5vol% mixed solution, the tensile / flex specimens were immersed in an airtight container, followed by a total of 33 cycles aging for 2 hours at 100 ° C and 1 hour at room temperature. Evaluate strength.