KR20100124621A - Resin composition of polyamide for automobile gear shift knob - Google Patents

Abstract

The present invention relates to an automobile gear shift resin composition, and more particularly, a polyamide 66 resin, a polyamide 6 resin, and a heat resistant ABS resin are mixed in a specific weight ratio, and a compatibilizer, short glass fiber, an antioxidant, and sodium The present invention relates to a resin composition having improved mechanical properties such as tensile strength, flexural strength, impact strength, heat resistance, and solvent resistance by adding a specific amount of a lubricant.

Description

Resin Composition of Polyamide for Automobile Gear Shift Knob}

The present invention relates to a polyamide resin composition for an automobile gear shift knob, a manufacturing method thereof, and an automobile gear shift knob manufactured by molding the same.

Generally, polyamide resin compositions have excellent mechanical properties, heat resistance and chemical resistance among crystalline resins. In addition, it is possible to obtain high physical properties such as mechanical strength and dimensional stability by reinforcing a thin-strand type reinforcement such as glass fiber and carbon fiber or powder type inorganic filler such as talc, wollastonite, calcium carbonate and barium sulfate. The development and application of high impact materials have also been realized by reinforcing various synthetic or mixed polymer elastomers. In addition, various functional additives may be added to increase physical and chemical resistance. Therefore, polyamide resin composition is widely used in many industrial fields such as ships, aircrafts as well as automobiles because it has the advantages of easier processing and lighter weight than metal, and has various and simple design and design effects as well as cost reduction effect due to high productivity. come.

In general, the resin for automotive gearshift knobs has been made of acrylonitrile butadiene styrene (ABS) resin, but it has excellent paintability but stress cracking at the core part where fusion lines are formed during coating. As this problem arises, instrumental analysis was conducted by previous researchers. However, no clear cause and solution have been provided. Therefore, an attempt was made to replace the elastomer-reinforced resin with polyamide 6 resin or polyamide 6 resin. However, mechanical strength, heat resistance, and solvent resistance were improved, but paintability was lower than that of existing materials, and appearance defects such as shrinkage occurred. Therefore, in order to solve the problem of cracking after painting of the gear shift knob core part, it is urgent to develop a resin with improved welding strength (weld strength) and solvent resistance and shrinkage resistance generated at the core part during molding.

As described above, a polyamide resin having improved heat resistance and chemical resistance is known in the art, but an improved material capable of minimizing shrinkage while simultaneously satisfying solvent resistance and high fusion resistance with ABS resin level There is no situation. Therefore, it has excellent paintability, high fusion and solvent resistance, and satisfies mechanical properties such as tensile strength, flexural strength, and impact strength as a material for automobile gear shift knobs, and does not cause stress cracks on core parts after coating. It is an object of the present invention to provide a polyamide resin composition for an automobile gear shift knob that does not have a poor appearance.

The present invention relates to a polyamide resin composition, and more particularly, to a polyamide resin, a polyamide 66 resin having excellent mechanical strength and heat resistance, a polyamide 6 resin having excellent fluidity and adhesion, and an ABS resin having excellent impact resistance and paintability. Glass fiber coated with a silane coupling agent, a compatibilizer that maleizes an imide rubber and an olefin rubber, and an phenol-based, phosphite-based antioxidant, and sodium-based lubricant as a antioxidant. The present invention relates to a polyamide resin composition useful for automotive gearshift knobs that solves the core (fusion line generation site) crack problem after coating while satisfying the heat resistance and impact resistance of the super heat resistant ABS resin.

As described above, according to the present invention, the polyamide resin composition has excellent heat resistance and chemical resistance at the same time as the conventional gear shift knob material composition, and has excellent mechanical properties such as tensile strength and flexural strength. It is applied to the gear shift knob to not only contribute to the performance improvement, but also to prevent the occurrence of environmental stress cracks, thereby improving the quality of the applied vehicle.

The present invention will be described in more detail as follows.

The present invention relates to polyamide 66 resin, polyamide 6 resin, heat-resistant ABS resin, imide- and olefin-based compatibilizers, short glass fibers, antioxidants, and lubricants. Imide type and olefin are used as a compatibilizer with glass short fiber coated with a silane coupling agent and a compatibilizer with a polyamide 66 resin with high strength and a polyamide 6 resin with excellent fluidity and adhesion. The two types of maleated copolymers are used to increase the compatibility and miscibility between different polymers, and they contain phenolic and phosphite antioxidants and sodium-based lubricants effective for improving coating performance. The present invention relates to a polyamide resin composition which is a material for automobile gear shift knobs having excellent stress cracking properties.

Each component of the polyamide composition for automobile gear shift knob of the present invention will be described in more detail as follows. Polyamide 66 resin and homogeneous polyamide 6 resin used in the present invention have a large difference in melting point and different flow characteristics, but are mixed and used to obtain synergistic effect of solvent resistance and fusion resistance, and heat resistant ABS maintains coating performance. It was used to mix to make. In addition, the glass short fibers were reinforced as a nucleating agent and an inorganic filler to lower the shrinkage rate. In order to improve the miscibility of the polyamide 66 resin and polyamide 6 resin, an olefin maleinized compatibilizer is added, and the imide male is obtained to obtain a micro-dispersion effect by improving the surface activity by lowering the interfacial tension between the polyamide resin and the ABS resin. A ignition compatibilizer was used.

The polyamide 66 resin is made by dehydration polycondensation of hexamethylene diamine and adipic acid, the polyamide 6 resin is made by ring-opening polymerization of ε-caprolactam, and the ABS resin is made of styrene and acrylonitrile in butadiene latex. It is made by mixing and extruding a ternary copolymer grafted by emulsion polymerization, a binary copolymer of acrylonitrile and styrene, and an additive at a predetermined ratio.

The polyamide 66 resin, polyamide 6 resin and heat-resistant ABS resin are mixed in a weight ratio of 30:30:40 to 40:40:20, and when the mixing ratio is less than 30:30:40, solvent resistance and shrinkage resistance may be reduced. The above range is preferable because it may cause problems such as deterioration of paintability and surface roughness when exceeding 40:40:20.

As the compatibilizer used in the present invention, an imide compatibilizer and an olefin compatibilizer are used as the maleated elastomer. Imide-based compatibilizer is added to increase the miscibility by minimizing the interfacial tension of the polyamide resin and ABS resin of different resins, the use content is in the range of 2 to 10 parts by weight based on 100 parts by weight of the polyamide resin and ABS resin When used as, less than 2 parts by weight of the lack of miscibility may reduce the impact resistance and coating performance, and more than 10 parts by weight of surface defects and fusion due to the fluidity can be dropped sharply the above range is preferred. Such imide-based compatibilizer is preferably one or a mixture of two selected from phenylmaleimide styrene polymer and phenylmaleide styrene acrylate. Another compatibilizer, an olefin compatibilizer, is added to improve the miscibility and impact resistance of the polyamide 66 resin and the polyamide 6 resin. The amount of the olefin compatibilizer is 2 to 10 weight parts based on 100 parts by weight of the polyamide resin and the ABS resin. The above range is preferable because it may be used in the range of less than 2 parts by weight, the impact resistance may be lowered, and when it exceeds 10 parts by weight, the surface resistance and coating performance may be reduced due to the decrease in shrinkage resistance and fluidity.

The short glass fibers used in the present invention have an average particle diameter of 9 to 13 µm, an average length of 3 to 5 mm, and coat 0.1 to 0.2% by weight of a silane coupling agent to give compatibility with the resin. Preference is given to coating amino silanes. When the particle diameter of the short glass fiber is less than 9 μm, the breakage rate of the short glass fiber is high, and thus the mechanical strength may be lowered. When the glass short fiber exceeds 13 μm, the appearance quality may be remarkably decreased due to excessive orientation of the glass fiber. When the coated silane coupling agent is less than 0.1% by weight, the mechanical strength and chemical resistance may be lowered, and when the amount of the coated silane coupling agent is greater than 0.2% by weight, the workability and the fusion property may be degraded. Such short glass fibers are used in the range of 10 to 30 parts by weight based on 100 parts by weight of the polyamide resin and the ABS resin. When the content of the short glass fibers is less than 10 parts by weight, the effect of reducing shrinkage may be remarkably reduced. When the weight part is exceeded, there may be a problem in that the coating performance is deteriorated due to a decrease in fusion and excessive surface expression of short glass fibers.

Antioxidants used in the present invention are added to improve heat and moisture resistance, and phenol and phosphite antioxidants are used. The phenolic antioxidant is used in the range of 0.1 to 0.3 parts by weight with respect to 100 parts by weight of the polyamide resin and the ABS resin, and when the content of the phenolic antioxidant is less than 0.1 parts by weight, heat aging resistance and moisture resistance may decrease. When the content is more than 0.3 part by weight, problems may occur in physical properties and appearance quality. As such a phenolic antioxidant, bis- (3,3-bis- (4-hydroxy-3-tetrabutylphenol) butanoic acid) -glycol ester having excellent laminating function is used. The phosphite-based antioxidant is used in the range of 0.1 to 0.3 parts by weight based on 100 parts by weight of the polyamide resin and the ABS resin, when the content of the phosphite-based antioxidant is less than 0.1 parts by weight may lower the heat aging resistance And, when more than 0.3 parts by weight may cause a problem that acts as a factor of property degradation. Such phosphite-based antioxidants include tris- (2,4-di-t-butylphenyl) -phosphite and tetrakis- (2,4-di-t-butylphenyl) -4,4'-biphenylene One or a mixture of two selected from diphosphites is used.

Sodium-based lubricant used in the present invention is added for flowability and releasability, the content is used in the range of 0.2 to 0.5 parts by weight based on 100 parts by weight of the polyamide resin and ABS resin, the content of sodium-based lubricant is 0.2 weight The above range is preferable because the release effect and the appearance quality may be lowered when the amount is less than the part, and the problem of deterioration of physical properties and the weld strength may be caused when the amount is more than 0.5 parts by weight. As such a sodium type lubricant, sodium octadecanoate etc. are used.

In addition, the production method of the polyamide resin composition of the present invention is produced by extrusion through a melt kneading process by a twin screw extruder, first, polyamide 66 resin, polyamide 6 resin and heat-resistant ABS resin 30:30:40 ~ 40 100 parts by weight of polyamide resin mixed in a weight ratio of 40:20, 2 to 10 parts by weight of imide-based compatibilizer, 2 to 10 parts by weight of olefin-based compatibilizer, 0.1 to 0.3 parts by weight of phenolic antioxidant and phosphite antioxidant 0.1 to 0.3 parts by weight and 0.2 to 0.5 parts by weight of a sodium lubricant are introduced into the main (primary) inlet of a twin screw extruder, with a particle diameter of 9 to 13 μm, a length of 3 to 5 mm, and a silane coupling agent of 0.1 to 0.2 weight 10 ~ 30 parts by weight of coated short fiber glass is fed into the slot (secondary) inlet with an automatic feeder. The extruder is a twin screw extruder with L / D 40 ~ 45 and D75 ~ 95 mm (ø). Melt kneading process at a screw rotation speed of 300 to 500 rpm Division is prepared by cooling, dehydration, granulation, screening, dehumidification drying and packaging operations. When the L / D is less than 40, the miscibility may be degraded, and thus, the mechanical properties may be degraded. When the L / D is more than 45, the mechanical properties may be deteriorated due to deterioration of the ABS and the compatibilizer. In addition, when the temperature is less than 260 ℃ miscibility may be lowered, and when 275 ℃ is exceeded may cause a problem that the mechanical properties are deteriorated, when the screw rotational speed is less than 300, miscibility, degradation of physical properties, productivity problems may occur The above range is preferable because it may cause a problem that the mechanical properties are significantly lowered due to deterioration, excessive glass short fiber breakage ratio, and the like, when exceeding 500.

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

Examples 1 and 2

In the examples and comparative examples, the symbol means the following contents.

1.Polyamide 66 Resin

1) PA66: Rhodia, France, STABAMID 27A

2. Polyamide 6 Resin

1) PA6: KP Chemtech, PAMIDE 2.8 product

3. Heat resistant ABS resin

1) ABS: LG Chem, XR401

4. Compatibilizer (maleification)

1) imide series: Japan's Shokubai, PSX0371

2) Olefin series: Kumho Polychem, KEPA1130

5. Short glass fiber

1) G / F: Owens Corning, CS123D-10P (average particle size 10 microns, fiber length 3.5 mm)

6. Antioxidant

1) Phenol: Bis- (3,3-bis- (4'-hydroxy-3'-tetrabutylphenyl) butanoic acid) -glycol ester

2) phosphite system: tris- (2,4-di-t-butylphenyl) -phosphite

7. Gliding

1) Sodium-based: sodium octadecanoic acid

As shown in Table 1, polyamide 66 resin, polyamide 6 resin, ABS resin, imide and olefin maleinized compatibilizer, phenolic antioxidant, phosphite antioxidant, and sodium lubricant are used in twin screw extruder. The primary feeder is put into the inlet, and the glass short fiber is fed into the side (secondary) inlet as an automatic feeder. The extruder is a twin screw extruder with L / D 40, D75 mm, and melt kneading at 400 rpm screw speed. And polyamide resin composition was prepared through the water tank cooling, dehydration, granulation, screening, dehumidification drying, packaging process.

Comparative Examples 1 to 4

The same procedure as in Example 1, except that the composition was prepared in the composition shown in Table 1.

Comparative Example 5

The same process as in Example 1, except that the screw was rotated to 550 rpm to prepare a composition.

division
(Parts by weight) Example Comparative example One 2 One 2 3 4 5 Polyamide
Suzy PA66 30 40 - 50 30 - 40 PA6 30 40 - 50 30 70 40 Heat resistant ABS resin 40 20 100 - 40 30 20 Short glass fiber 15 15 - 15 25 8 15 Compatibilizer Imide 3 5 - 3 5 5 5 Olefin 5 8 - 10 5 8 8 Antioxidant Phenolic 0.15 0.15 0.1 0.3 0.15 0.15 0.15 Phosphite 0.15 0.15 0.1 0.2 0.15 0.15 0.15 Lubricant 0.2 0.2 0.3 0.2 0.15 0.2 0.2 Screw rpm 400 400 400 400 400 400 550

Experimental Example

The physical properties of the compositions prepared in Examples 1 and 2 and Comparative Examples 1 to 5 were measured and shown in Table 2 below.

<Measurement method>

1. Weld strength: Weld strength specimens were formed in which the weld line was formed at the center of the specimen by installing one gate of tensile strength specimen of ASTM D638 standard at each side end, and according to the same test standard (ASTM D638) Was carried out. The reference value should be at least 550.

2. Solvent resistance: Chemical resistance jig evaluation

Tensile strength specimens of ASTM D638 standard were fixed in a chemical resistance evaluation jig, and the coating solvent was applied to the gauze for 30 minutes at room temperature, and then allowed to stand in an oven at 80 ℃ for 5 hours. It was evaluated whether silk cracks or hair cracks occurred on the surface. The baseline should be free of hair cracks.

3. Stress Crack Reliability Evaluation (Ⅰ, Ⅱ, Ⅲ)

Ⅰ) Degradation experiment

The gear shift knob prepared with the composition of Example 2 (MS standard coating product) was placed in an aging oven at 100 ° C. and deteriorated for 24 hours, and then cooled at room temperature to check for cracks. The evaluation criteria shall not generate fine cracks (hair cracks).

Ⅱ) Cold heat cycle experiment

The gear shift knob prepared with the composition of Example 2 (MS standard coating product) was placed in a test chamber and subjected to 5 cycles of 100 ° C., 3 hours → −30 ° C., 3 hours → 50 ° C., 90% humidity, and 7 hours. After cracking was confirmed. The evaluation criteria shall not generate fine cracks (hair cracks).

Ⅲ) Quenching Experiment

The gear shift knob prepared with the composition of Example 2 (MS standard coating product) was immersed in a liquid nitrogen container corresponding to -196 ° C for 10 seconds, and then taken out to check for cracks. Evaluation criteria shall not generate fine cracks (hair cracks).

4. Shrinkage Rate Evaluation: Shrinkage Rate Measurement of 3˝ × 5 ″ × 1/8 ″ The specimens were injection molded to compare and evaluate the lateral and vertical shrinkage rates. Evaluation criteria were set to aim to improve the shrinkage rate by more than 20% compared to the heat-resistant ABS of existing materials.

5. Paintability Evaluation (Film Peeling Experiment): The peeling test of the gear shift knob plane part made of MS standard coating is carried out to evaluate the peeling of the coating film. The evaluation criteria shall not cause peeling.

6. Tensile strength: Performed according to ASTM D638. The reference value shall be at least 940 kg / cm ² .

7. Elongation: It was carried out according to ASTM D-638. The reference value should be at least 10%.

8. Flexural Strength: Performed according to ASTM D-790. The reference value shall be at least 1,175 kg / cm ² .

9. Flexural modulus: It was performed according to ASTM D-790. The reference value shall be at least 36,600 kg / cm ² .

10. Izod impact strength was conducted according to ASTM D-256. The reference value should be at least 5 kg / cm ² .

11. Heat deflection temperature: It was carried out in accordance with ASTM D-648. The reference value should be at least 174 ° C.

division Example Comparative example One 2 One 2 3 4 5 Weld Strength (kg / cm ² ) 608 646 365 513 537 573 556 Solvent resistance (with or without cracks) radish radish radish radish radish radish radish Stress Crack Reliability
(With or without crack)
Deterioration radish radish U radish radish radish radish Cold cycle experiment radish radish U radish radish radish radish Quench experiment radish radish U radish U radish radish Evaluation of paintability (peelability) radish radish radish U U radish radish Mold Shrinkage (%) 0.42 0.38 1.14 0.34 0.30 0.62 0.37 Tensile Strength (kg / cm ² ) 998 1,075 458 1,104 987 1,050 985 % Elongation 15.3 12.1 45.0 15.6 18.8 18.6 20.2 Flexural Strength (kg / cm ² ) 1,275 1,315 660 1,476 1,226 1,185 1,234 Flexural modulus (kg / cm ² ) 39,640 41,450 20,600 53,750 40,510 35,215 38,530 Izod impact strength
(kgcm / cm) 15.2 18.4 14.5 13.6 12.8 16.5 11.8 Heat deflection temperature (℃) 178 182 95 221 183 176 178

According to the results of Table 2, the polyamide resin composition of the Example is superior in weld strength, stress cracking, and paintability compared to the comparative example, and mechanical strength and thermal properties are superior to Comparative Example 1, which is similar in composition to the existing material. appear.

Therefore, as a material for automotive gearshift knobs, it has heat resistance solvent resistance and stress cracking resistance that do not generate environmental stress crack in the welded part after coating, and Comparative Example 1 is a similar composition of the existing heat resistant ABS material and has weld strength and heat resistance. There is a problem that the weakness of the back and other mechanical properties are not only remarkably deteriorated, but also the appearance quality due to shrinkage is deteriorated due to high molding shrinkage rate. Comparative Example 2 is excellent in mechanical and thermal properties, but the weld strength is slightly lowered and paintability is poor. And, Comparative Example 3 had a disadvantage in that the paintability and the appearance quality is significantly lowered by the display of short glass fibers, Comparative Example 4 has the best appearance quality, but the molding shrinkage rate is rather high, the appearance quality is reduced by the shrinkage problem In Comparative Example 5, the impact strength was somewhat increased due to an increase in the breaking rate of the short glass fibers due to the increase in the shear force. It showed eojineun trends.

Claims (6)

100 parts by weight of a polyamide 66 resin, a polyamide 6 resin, and a heat-resistant acrylonitrile butadiene styrene resin in a 30:30:40 to 40:40:20 weight ratio; As a compatibilizer, 2 to 10 parts by weight of an imide compatibilizer and 2 to 10 parts by weight of an olefin compatibilizer; 10 to 30 parts by weight of short glass fibers coated with an average particle diameter of 9 to 13 μm, an average length of 3 to 5 mm, and coated with 0.1 to 0.2% by weight of a silane coupling agent; 0.1 to 0.3 parts by weight of spent phenol and 0.1 to 0.3 parts by weight of phosphite as antioxidant; A polyamide resin composition for automobile gear shift knobs containing 0.2 to 0.5 parts by weight of a sodium lubricant. In claim 1, Wherein the compatibilizer is an imide-based compatibilizer is a polyamide resin composition for a vehicle gear shift knob, characterized in that one or two selected from phenylmaleimide styrene polymer and phenylmaleimide styrene acrylate. In claim 1, The phenolic antioxidants include bis- (3,3-bis- (4'-hydroxy-3'-tetrabutylphenyl) butanoic acid) -glycol esters; The phosphite-based antioxidants include tris- (2,4-di-t-butylphenyl) -phosphite and tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene diphosphite One or two or more kinds selected from among them; Polyamide resin composition for automobile gear shift knob characterized in that the. In claim 1, The sodium-based lubricant is sodium octadecanoate, polyamide resin composition for a vehicle gear shift knob. 1) 100 parts by weight of polyamide 66 resin, polyamide 6 resin and heat resistant ABS resin in a weight ratio of 30:30:40 to 40:40:20, 2) 2 to 10 parts by weight of an imide-based compatibilizer 2 to 10 parts by weight of an olefin compatibilizer, 3) an average particle diameter of 9 to 13 μm, an average length of 3 to 5 mm, and 10 to 30 parts by weight of short glass fibers coated with 0.1 to 0.2 wt% of a silane coupling agent, 4) 0.1 ~ 0.3 parts by weight of waste antioxidants and 0.1 ~ 0.3 parts by weight of phosphite antioxidants as antioxidants, and 5) 0.2 ~ 0.5 parts by weight of sodium lubricants as lubricants in a twin screw extruder at an extrusion temperature of 260 ~ 275 ℃. Method for producing a polyamide resin composition for a vehicle gear shift knob characterized in that the extrusion through the melt kneading process at a screw rotation speed of 300 ~ 500 rpm. An automobile gear shift knob manufactured by molding the composition of any one of claims 1 to 4.