KR20150139707A - Thermoplastic resin composition and molded part for automobile using the same - Google Patents

Abstract

The present invention relates to a thermoplastic resin composition for a vehicle, comprising 0.1 to 10 parts by weight of polyvalent alcohol having two to eight hydroxyl groups, 0.1-10 parts by weight of a chelating agent having an aliphatic polyvalent carboxylic acid of C1 to C10 (not including carbons of a carboxyl group) having two to four carboxyl groups for 100 parts by weight of the semi-aromatic polyamide resin. The thermoplastic resin composition according to the present invention maintains mechanical properties even after exposed at high temperature by excellent long term heat resistant stability, thereby being proper to be used as parts around an engine room in an under hood area of a vehicle.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition for automobiles,

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition for automobiles, and more particularly to a polyamide resin composition excellent in long-term heat-resistance stability, which is used for automobile parts.

The polyamide resin has excellent performance in heat resistance, abrasion resistance, chemical resistance and flame retardancy, and is used in a wide range of fields such as electric parts, electronic parts, and automobile parts.

Particularly, in the field of automobiles, plastic parts of metal parts are progressing in accordance with the tendency of light weight, and in particular, parts surrounding the engine room, which is the under the hood area of automobiles, are exposed to high temperature environment for a long time. A composition is used.

In general, an organic antioxidant such as a phenol-based or phosphite-based resin is widely used for securing long-term heat stability of a polyamide resin composition, but there is a limitation in improving the property of maintaining excellent physical properties at a high temperature for a long time at a satisfactory level .

Also, a copper halide type heat stabilizer such as a CuI / KI mixture, which is known to have excellent long-term thermal stability at a high temperature, is used as compared with an organic antioxidant. Copper is discolored or precipitated with time, Problems may arise when used on parts.

Therefore, it is necessary to study a polyamide resin composition which is resistant to thermal aging which can retain physical properties with high heat stability even if it is exposed to high temperature for a long time so that it can be used for parts around an automobile engine room.

An object of the present invention is to provide a thermoplastic resin composition for automobiles which can maintain mechanical strength for a long period of time in a high temperature environment and which has excellent long-term heat stability and ease of processing.

In order to achieve the above object, the thermoplastic resin composition for automobiles according to one embodiment of the present invention comprises a semiaromatic polyamide resin, a polyhydric alcohol having 2 to 8 hydroxy groups per 100 parts by weight of the semiaromatic polyamide resin And 0.1 to 10 parts by weight of a chelating agent comprising an aliphatic polycarboxylic acid of C1 to C10 (containing no carbon of the carboxyl group) having 2 to 4 carboxyl groups.

The polyhydric alcohol may include a compound represented by the following general formula (1).

[Chemical Formula 1]

(In the above formula (1), n is an integer of 1 to 3)

The semiaromatic polyamide resin may be composed of a dicarboxylic acid unit and an aliphatic or alicyclic diamine unit in which the repeating unit contains an aromatic dicarboxylic acid unit in an amount of 10 to 100 mol%.

The semiaromatic polyamide resin is a polyamide (PA6T / 66) composed of hexamethylene terephthalamide and hexamethylene adipamide; Or a polyamide (PA6T / DT) composed of hexamethylene terephthalamide and 2-methylpentamethylene terephthalamide.

The semi-aromatic polyamide resin may have a glass transition temperature (Tg) of 80 to 150 ° C.

The weight ratio of the polyhydric alcohol to the chelating agent may be 1: 0.2 to 1:10.

The automotive thermoplastic resin composition may further comprise 10 to 100 parts by weight of glass fibers with respect to 100 parts by weight of the semiaromatic polyamide resin.

The aforementioned tensile strength a of the automotive thermoplastic resin composition after elapse of 500 hours at 220 캜 with respect to the initial tensile strength a ₀ measured according to the evaluation method of ASTM D638 can be expressed by the following formula 1.

[Formula 1]

A molded article for an automobile according to an embodiment of the present invention can be produced from the above-mentioned automotive thermoplastic resin composition.

The automotive molded article may be a water temperature controller, a thermostat housing, or a fuel rail.

INDUSTRIAL APPLICABILITY The thermoplastic resin composition for automobiles of the present invention has excellent long-term heat stability and can stably maintain initial physical properties even when exposed to a high temperature environment for a long time.

In addition, it is possible to reduce the generation of gas due to thermal decomposition of the thermoplastic resin composition at high temperatures during the processing of the automotive thermoplastic resin composition, and therefore, the processability is excellent.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described in detail below. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

Hereinafter, the automotive thermoplastic resin composition of the present invention will be described.

The thermoplastic resin composition for automobiles according to one embodiment includes a semi-aromatic polyamide resin, a polyhydric alcohol, and a chelating agent.

Each component of the automotive thermoplastic resin composition according to one embodiment of the present invention will be described in detail.

Semi-aromatic ( semi - aromatic ) Polyamide resin

As the polyamide resin, a highly heat-resistant, semi-aromatic polyamide resin can be used.

The semiaromatic polyamide resin may be a homopolymer, a copolymer, a terpolymer or a polymer formed from a monomer containing an aromatic group, wherein the term copolymer refers to a copolymer of two or more amide and / ≪ / RTI >

Specifically, the semi-aromatic polyamide resin is a dicarboxylic acid monomer containing an aromatic dicarboxylic acid in an amount of 10 to 100 mol% ) And an aliphatic diamine or an alicyclic diamine. Specifically, the aliphatic or alicyclic diamine monomer may have 4 to 20 carbon atoms, and the aromatic dicarboxylic acid monomer may be, for example, terephthalic acid or isophthalic acid, Benzene ring.

In other words, in the semi-aromatic polyamide resin, the repeating unit is composed of a dicarboxylic acid unit and an aliphatic or alicyclic diamine unit, and the dicarboxylic acid unit is an aromatic dicarboxylic acid unit of 10 To 100 mol%.

The aromatic dicarboxylic acid unit is, for example, terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,4- Phenylenedioxydiacetic acid, 1,3-phenylene dioxydiacetic acid, diphenic acid, 4,4'-oxydibenzoic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone- -Dicarboxylic acid, or 4,4'-biphenyldicarboxylic acid.

The dicarboxylic acid unit may further include a unit derived from a non-aromatic dicarboxylic acid other than the aromatic dicarboxylic acid unit. The non-aromatic dicarboxylic acid may be an aliphatic or alicyclic dicarboxylic acid. For example, the non-aromatic dicarboxylic acid is selected from the group consisting of malonic acid, dimethyl malonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid , Aliphatic dicarboxylic acids such as 2,2-diethyl succinic acid, azelaic acid, sebacic acid, and suberic acid; Or a unit derived from an alicyclic dicarboxylic acid such as 1,3-cyclopentanedicarboxylic acid or 1,4-cyclohexanedicarboxylic acid, or a nonaromatic dicarboxylic acid.

These non-aromatic dicarboxylic acid units may be used alone or in combination of two or more. The content of the non-aromatic dicarboxylic acid unit in the dicarboxylic acid unit may be 90 mol% or less, specifically 80 mol% or less, 70 mol% or less, and 60 mol% or less.

The aliphatic diamine unit may be derived from an aliphatic alkylenediamine having 4 to 18 carbon atoms. The aliphatic alkylenediamine having 4 to 18 carbon atoms is preferably 1,6-hexanediamine, 1,7-heptanediamine, 1,8- Linear aliphatic alkylenediamines such as octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine; And 1-butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-dimethyl-1,4-butanediamine, -Methyl 1,5-pentanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3- , 2-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6- hexanediamine, Hexanediamine, 2,2-diethyl-1,7-heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl- 1,7-hexanediamine, dimethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, Octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4- 1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3- And branched aliphatic alkylenediamines such as methyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine and 5-methyl-1,9-nonanediamine. .

The aliphatic diamine unit includes, for example, 1,6-hexanediamine, 1,7-heptanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, , 1-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl- 1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl- - pentanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3- , 6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2,4- 1,7-heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine and 2,5- -Heptanediamine. ≪ / RTI >

The semiaromatic polyamide resin may be selected from the group consisting of poly (m-xylene adipamide) (PAMXD6), poly (dodecamethylene terephthalamide) (PA12T), poly (decamethylene terephthalamide) Polyamide (PA6T / 66) comprising hexamethylene terephthalamide (PA9T), hexamethylene terephthalamide and hexamethylene adipamide, polyamide (PA6T / DT) consisting of hexamethylene terephthalamide and 2-methylpentamethylene terephthalamide, (PA6T / 6I / 66) composed of a polyamide (PA6I / 66) consisting of a polyamide (PA6I / 66), a polyamide (PA6I / 66) Copolymers and mixtures thereof.

Preferably, a polyamide (PA6T / 66) consisting of hexamethylene terephthalamide and hexamethylene adipamide or a polyamide (PA6T / DT) consisting of hexamethylene terephthalamide and 2-methylpentamethylene terephthalamide or a combination thereof , And more preferably PA6T / 66 can be used.

The semiaromatic polyamide resin is a resin capable of exhibiting high heat resistance, and the glass transition temperature (Tg) of the semiaromatic polyamide resin may be 80 to 150 ° C, preferably 85 to 120 ° C .

The molecular weight of the above-mentioned semi-aromatic polyamide resin is not particularly limited, and an intrinsic viscosity (IV) of 0.75 or more, specifically 0.75 to 1.15 can be used.

Polyhydric alcohol

Polyhydric alcohol refers to an alcohol having two or more hydroxyl groups (hydroxyl groups, -OH) in the molecule. In the present invention, the number of hydroxyl groups may be 2 to 8.

The polyhydric alcohols of the present invention may contain substituents selected from aliphatic, cyclic aliphatic, arylaliphatic and aromatic compounds and may contain one or more heteroatoms such as oxygen, nitrogen or sulfur. The polyhydric alcohol may contain one or more substituents such as an ether, a carboxylic acid, an amide, or an ester.

Specific examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, , 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, 1,4-benzene dimethanol, 1,5- Trimethylolpropane, hexane-1,2,6-triol, 2,3-di- (2'-hydroxyethyl) cyclohexan-1-ol, 1,1-tris- (4'- Ethane, 2- (2'-hydroxyethoxy) hexane-1,2-diol, 1,1,1-tris- [(2'-hydroxyethoxy) methyl] - (hydroxymethyl) ethane, 1,1,5-tris- (hydroxyphenyl) -3-methylpentane, 1,2,4-butanetriol, 1,2,3- , 6-hexanetriol, glycerol, diglycerol, triglycerol, 1,2,3,6-hexanetrol, tetraglycerol, pentaglycerol or Hexaglycerol may be used, or they may be used alone or in admixture of two or more.

The polyhydric alcohol is effective for suppressing the decomposition of the polyamide resin at high temperature, and is preferably a polyol including a compound represented by the following formula (1).

[Chemical Formula 1]

(In the above formula (1), n is an integer of 1 to 3)

In the above formula (1), when n is 1, monopentaerythritol (MPE) and n is 2, dipentaerythritol (DPE) and n is 3, tripentaerythritol (TPE) Dipentaerythritol is effective.

Monopentaerythritol can be prepared by condensation of one molecule of acetaldehyde and four molecules of formaldehyde by an alkali catalyst such as sodium hydroxide or potassium hydroxide, and dipentaerythritol and tripentaerythritol Can be obtained by condensing monopentaerythritol by heating at 260 ° C or higher, which is the melting point of monopentaerythritol.

Since the polyhydric alcohol includes a plurality of hydroxyl groups, it oxidizes the surface at the time of aging at a high temperature to promote formation of char on the surface, thereby preventing penetration of the oxide layer into the thermoplastic resin, And the long-term stability of the heat resistance is improved. In addition, long-term heat stability can be remarkably improved by using a chelating agent to be described later simultaneously with a polyhydric alcohol.

The polyhydric alcohol may be used in an amount of 0.1 to 10 parts by weight, preferably 0.3 to 9 parts by weight, based on 100 parts by weight of the semi-aromatic polyamide resin. When the amount of the polyhydric alcohol is less than 0.1 part by weight, the thermoplastic resin decomposes and the stability of long-term heat resistance deteriorates. When the amount of the polyhydric alcohol exceeds 10 parts by weight, the effect of improving long-term heat stability is not increased.

Chelating agent

The chelating agent may include aliphatic polycarboxylic acids of C1 to C10 (not including the carbon of the carboxyl group) having 2 to 4 carboxyl groups. Two or more kinds of different aliphatic polyvalent carboxylic acids may be used in combination, and derivatives of carboxylic acids such as acid anhydrides, acid chlorides and esters thereof may be used.

Specific examples thereof include fumaric acid, succinic acid, 3,3-diethylsuccinic acid, malonic acid, dimethylmalonic acid, tartaric acid ), Maleic acid, citric acid, malic acid, adipic acid, 2-methyladipic acid, tri-methyladipic acid, itaconic acid, glutaric acid, 2,2-dimethylglutaric acid, pimelic acid, azelaic acid, dimer, The present invention relates to a process for the preparation of a compound of the formula (I), wherein the compound is selected from the group consisting of dimer acid, sebacic acid, suberic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, citraconic acid, Tetrahydrophthalic acid, 1,2,3,4-butanetetracarboxylic acid or oxalic acid, and may be used alone or in combination. Two or more kinds may be mixed.

The chelating agent may be used in an amount of 0.1 to 10 parts by weight, preferably 1 to 9 parts by weight, based on 100 parts by weight of the semi-aromatic polyamide resin. If the chelating agent is out of the above range, the effect of improving long-term heat stability may be deteriorated.

When glass fiber is added for the purpose of strengthening the chelating agent, the effect of improving the long term heat stability can be increased.

In the production of fiberglass, hair-like filaments are subjected to a surface treatment process in which the surface is coated by a chemical mixture called sizing, and in general, sizing protects the filaments from friction at the contact surfaces of all processes carried out by the glass fiber Or to facilitate the bonding of the glass fiber and the resin.

When the glass fiber is treated with a sizing material, it is dried in the form of a chopped strand, where the solvent evaporates and the sizing material is deposited in the form of a residue that lightly coats the surface of the glass fiber.

The chelating agent reacts with and bonds with the sizing material coated on the surface of the glass fiber, so that the long-term heat stability can be improved.

In detail, the glass fiber used as the filler can be determined according to the structure of the silicate network. The alkali oxide of the glass fiber is not easily incorporated into the silicate network structure, which causes the strength to be lowered. When the chelating agent is used, it can bind with the sizing material of the glass fiber and suppress the action of the alkali oxide, so that the strength can be maintained even when exposed to a high temperature for a long time.

The weight ratio of the chelating agent and the polyhydric alcohol may be 1: 0.2 to 1:10, and preferably 1: 0.2 to 1: 5.

When the weight ratio of the chelating agent and the polyhydric alcohol is less than 1: 0.2, the effect of improving the long-term heat stability is small. When the weight ratio of the chelating agent and the polyhydric alcohol is more than 1: 5, And thus the appearance characteristics may be remarkably deteriorated. Therefore, when the content ratio of the chelating agent to the polyhydric alcohol is in the above range, the effect of improving the long-term heat stability can be maximized.

Glass fiber

The automotive thermoplastic resin composition may further comprise glass fiber, and the desired level of mechanical strength can be secured by controlling the addition amount of the glass fiber.

Glass fiber has the characteristics of high tensile strength, heat resistance and moisture resistance, and glass fiber has good dimensional stability because it is hardly shrunk or stretched according to changing environmental conditions.

The glass fiber may be any of those conventionally used in the art, having a diameter of 8 to 20 탆 and a length of 1.5 to 8 mm. When the diameter of the glass fiber is within the above range, an excellent strength reinforcement effect can be obtained. When the length of the glass fiber is within the above range, it is easy to input into the processing equipment such as an extruder and the strength reinforcing effect can be greatly improved.

The glass fibers may be used in combination with fibers selected from the group consisting of carbon fibers, basalt fibers, fibers produced from biomass, and combinations thereof. The biomass refers to an organism that uses plants and microorganisms as an energy source.

The glass fiber may have a circular, oval, rectangular, or dumbbell shape having two circular cross-sections.

The glass fibers may have a cross-sectional aspect ratio of less than 1.5. Specifically, a circular cross-sectional shape having an aspect ratio of 1 may be used. Wherein the aspect ratio is defined as the ratio of the longest diameter to the smallest diameter in the cross section of the glass fiber. When the glass fiber having the aspect ratio range of the cross section is used, the cost of the product can be reduced in terms of cost, and the glass fiber having a circular section can be used to improve dimensional stability and appearance.

The glass fiber may be treated with a predetermined sizing material to prevent the reaction with the resin and improve the degree of impregnation. The treatment of the glass fiber can be performed during the production of the glass fiber or in a post-treatment.

The glass fiber may be 10 to 100 parts by weight based on 100 parts by weight of the semiaromatic polyamide resin.

In one embodiment of the present invention, the automotive thermoplastic resin composition may further include additives according to each application.

The additive may be a dye, a pigment, a filler, a heat stabilizer, a UV stabilizer, a lubricant, an antibacterial agent, a release agent, a nucleating agent, an antistatic agent, an antioxidant or an inorganic additive. These may be used alone or in combination of two or more.

The additive may be used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the semiaromatic polyamide resin.

The above-mentioned automotive thermoplastic resin composition is excellent in long-term heat stability due to the use of a polyhydric alcohol and a chelating agent, and does not deteriorate other properties such as abrasion resistance, chemical resistance, flame retardancy and mechanical strength of the polyamide resin.

Accordingly, the tensile strength a of the thermoplastic resin composition for automobile according to one embodiment of the present invention after elapse of 500 hours at 220 캜, based on the initial tensile strength a ₀ measured according to the evaluation method of ASTM D638, is expressed by the following formula 1 .

[Formula 1]

As shown in the formula (1), the thermoplastic resin composition for automobile according to the present invention can maintain initial physical properties even if it is left for a long time at a high temperature.

The thermoplastic resin composition for automobile according to the present invention can be produced by a known method for producing a resin composition. For example, it can be produced in the form of pellets by mixing the components of the present invention and other additives simultaneously and melt extruding in an extruder.

The above-mentioned automotive thermoplastic resin composition can be preferably applied to a molded article requiring heat resistance, and can be applied to any type of molded article requiring heat resistance.

Specifically, the present invention is applicable to applications such as a water temperature controller, a thermostat housing or a fuel rail, and the application range is not limited thereto.

[Experimental Example]

Hereinafter, the results of experiments conducted to demonstrate the excellent effects of the thermoplastic resin composition for automobiles of the present invention are shown.

The components used in the thermoplastic resin compositions of the following examples and comparative examples are as follows.

(a) a semiaromatic polyamide resin

A6000, a PA6T / 66 product from Solvay, was used.

(b) a polyhydric alcohol

Dipentaerythritol manufactured by Samyang Chemical Industry Co., Ltd. was used.

(c) a chelating agent

Citric acid anhydride of Samcheon Chemical Co. was used.

(d) glass fiber

983, a glass fiber product having a diameter of 10 탆, a chop length of 4 mm and an elliptical cross-section, manufactured by Owens corning was used.

(e) Heat stabilizer

TP-H9008, a mixture of CuI / KI from Brueggemann, was used.

The thermoplastic resin compositions of Examples and Comparative Examples were prepared in accordance with the component content ratios described in Table 1 below.

The ingredients listed in Table 1 were placed in a mixer and dry mixed. Then, the mixture was fed into a twin-screw extruder having an L / D of 45 and a diameter of 45 mm, and a thermoplastic resin composition in the form of a pellet was produced through an extruder. Specimens for the evaluation of physical properties were prepared using an injection molding machine set at 330 캜.

The content of each component listed in Table 1 is expressed in terms of parts by weight based on 100 parts by weight of the semiaromatic polyamide resin (a).

Constituent (a) (b) (c) (d) (e)
Example One 100 2.4 1.6 56.0 - 2 100 8.5 1.7 59.3 - 3 100 0.3 1.5 54.9 - 4 100 2.6 8.5 59.8 -



Comparative Example One 100 - - 54.0 0.3 2 100 1.6 - 54.9 0.3 3 100 3.2 - 55.7 0.3 4 100 2.4 - 55.1 - 5 100 - 1.6 54.9 0.3 6 100 - 1.6 54.7 - 7 100 1.7 10.3 60.3 - 8 100 - 3.2 55.6 - 9 100 10.3 0.5 60.3 - 10 100 0.05 1.7 55.0 -

The thermoplastic resin compositions of Examples 1 to 4 and Comparative Examples 1 to 10 were evaluated for long-term heat stability and gas generation. Evaluation methods of evaluation items are as follows, and evaluation results of the respective items are shown in Table 2 below.

<Evaluation of long-term heat stability>

A part of each of the specimens prepared using the thermoplastic resin compositions of Examples 1 to 4 and Comparative Examples 1 to 10 was allowed to stand at 23 DEG C and 50% RH for 48 hours, and then the initial tensile strength (a ₀ ) Were measured. At this time, the measurement speed of the tensile strength was 5 mm / min. Thereafter, the tensile strength (a) of each of the specimens after being left at 220 ° C for 500 hours was measured. The long-term heat stability was evaluated by the tensile strength retention ratio calculated using the following formula 2.

[Formula 2]

&Lt; Evaluation of gas generation amount >

About 5 g of the pellets prepared using the thermoplastic resin compositions of Examples 1 to 4 and Comparative Examples 1 to 10 were weighed into a petri dish and then closed with a dish cap. Was placed on a hot plate and the amount of volatiles adsorbed on the dish cap was measured. The amount of gas generation was calculated using Equation 3 below.

[Formula 3]

(Where C is the weight of the dish after evaluation, C ₀ is the dish cap weight before evaluation, and S is the pellet-free game used in the evaluation)

Evaluation items Early
The tensile strength
(kgf / cm ² ) 220 占 폚 / 500 hours elapsed Tensile strength
(kgf / cm ² ) The tensile strength
Retention rate
(%) Gas generation amount
(ppm)
Example One 2,010 1,923 96 720 2 2,150 2,098 98 980 3 2,035 1,931 95 760 4 2,138 1,953 91 810



Comparative Example One 1,917 1,258 66 550 2 2,092 1,159 55 770 3 2,057 1,046 51 820 4 2,026 1,739 86 630 5 2,118 1,152 54 510 6 2,133 1,333 62 580 7 2,013 1,691 84 740 8 2,181 1,374 63 650 9 2,058 1,708 83 2,800 10 2,120 1,345 63 630

From Table 1 and Table 2, it was found that when the thermoplastic resin composition of Examples 1 to 4 was used, the initial tensile strength and the tensile strength retention were excellent, the long-term heat stability was excellent, I could.

It was found that the long-term heat stability of the thermoplastic resin composition according to the examples was remarkably lowered even when the conventional copper halide-based compound (Comparative Examples 1, 2, 3 and 5) was used.

In addition, when citrate anhydride, which is a chelating agent, was used alone (Comparative Examples 6 and 8) and only dipentaerythritol (polyhydric alcohol) was used (Comparative Example 4) And that it was vulnerable to.

Even when the polyol and chelating agent are both included in the thermoplastic resin composition, when the content of each component is out of the range of the present invention or the weight ratio of polyol to chelating agent is out of the range of 1: 0.2 to 1:10 Examples 7, 9 and 10) show that the tensile strength retention rate is low and the long-term heat stability is poor or the gas generation amount is large and the processability is poor.

The use of a polyhydric alcohol and a chelating agent in a semiaromatic polyamide resin together with a chelating agent has a synergistic effect of maintaining the tensile strength and reducing the generation of gas due to thermal decomposition even after prolonged exposure to a high temperature environment.

The scope of the present invention is not limited to the above-described embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (10)

A semi-aromatic polyamide resin,
Based on 100 parts by weight of the above-mentioned semi-aromatic polyamide resin,
0.1 to 10 parts by weight of a polyhydric alcohol containing 2 to 8 hydroxy groups,
And 0.1 to 10 parts by weight of a chelating agent comprising an aliphatic polycarboxylic acid of C1 to C10 (containing no carbon of the carboxyl group) having 2 to 4 carboxyl groups.
The method according to claim 1,
Wherein the polyhydric alcohol comprises a compound represented by the following formula (1).

[Chemical Formula 1]

(In the above formula (1), n is an integer of 1 to 3)
The method according to claim 1,
The above-mentioned semiaromatic polyamide resin is a
Wherein the repeating unit is a dicarboxylic acid unit containing an aromatic dicarboxylic acid unit in an amount of 10 to 100 mol%
An aliphatic or alicyclic diamine unit.
The method according to claim 1,
The semiaromatic polyamide resin is a polyamide (PA6T / 66) composed of hexamethylene terephthalamide and hexamethylene adipamide; Or a polyamide (PA6T / DT) composed of hexamethylene terephthalamide and 2-methylpentamethylene terephthalamide.
The method according to claim 1,
Wherein the semi-aromatic polyamide resin has a glass transition temperature (Tg) of 80 to 150 占 폚.
The method according to claim 1,
The weight ratio of the polyhydric alcohol to the chelating agent is 1: 0.2 to 1:10.
The method according to claim 1,
Wherein the automotive thermoplastic resin composition further comprises 10 to 100 parts by weight of glass fibers per 100 parts by weight of the semiaromatic polyamide resin.
The method according to claim 1,
With respect to the initial tensile strength a ₀ measured according to the evaluation method of ASTM D638,
And the tensile strength &quot; a &quot; after elapse of 500 hours at 220 deg. C is expressed by the following formula (1).
[Formula 1]

A molded article for automobile produced from the thermoplastic resin composition for automobile according to any one of claims 1 to 8.
10. The method of claim 9,
The automotive molded article may be a water temperature controller, a thermostat housing or a fuel rail.