JPH05262980A - Thermoplastic resin composition and molded article thereof - Google Patents

Abstract

(57) [Summary] [Structure] The thermoplastic resin composition of the present invention has a melting point of 28.
Polyamide (A) having a temperature of 0 ° C. or higher, particularly preferably a melting point of 3
Specific aromatic polyamide (A-1) exceeding 00 ° C, hindered phenolic antioxidant (B) having a molecular weight of 500 or more and a TGA 10% weight loss temperature of 300 ° C or more, and TGA 10% weight loss temperature of a molecular weight of 600 or more Is 280
It is composed of a sulfur-based antioxidant (C) having a temperature of not less than 0 ° C. Also,
The molded article of the present invention is formed from the above thermoplastic resin composition. [Effect] The thermoplastic resin composition of the present invention has excellent thermal stability.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel thermoplastic resin composition and a molded article thereof. More specifically, the present invention relates to a novel thermoplastic resin composition excellent in heat aging resistance and a molded article thereof.

[0002]

BACKGROUND OF THE INVENTION Polyamide resins are excellent in heat resistance, oil resistance, moldability, rigidity, toughness, and other characteristics, so that they are used in electric tools, general industrial parts, mechanical parts, electronic parts, and automobiles. It is used as a resin for forming various functional parts such as exterior parts, engine room parts, and automobile electrical parts. In these applications, since the heat resistance of the polyamide resin is further required, polyamide 46, polyamide 6T6, polyamide 6T10, polyamide 6TI, polyamide 6TI6, polyamide 6TI10, polyamide M are used instead of the conventional aliphatic polyamide.
High-melting polyamides such as XD6 and polyamide PXD6 are often used.

Among these, a polyamide obtained by polycondensing an aromatic dicarboxylic acid with a diamine using an aromatic dicarboxylic acid as a dicarboxylic acid component, that is, an aromatic polyamide has a particularly high melting point and short-term heat resistance. Excellent in Furthermore, since this aromatic polyamide has the above-mentioned excellent short-term heat resistance and a low water absorption rate,
It also has an advantage that there is no problem such as a decrease in dimensional accuracy and a change in physical properties caused by water absorption of the molded product.

However, since these aromatic polyamides have high melting points, the processing temperature at the time of preparing a compound or at the time of molding becomes high. Therefore, problems such as heat deterioration during processing and gas burning occur. Also, since the long-term heat resistance is poor, when the molded product is used at a high temperature, it becomes extremely brittle. Some of the molded products formed from such aromatic polyamides are exposed to a high temperature environment for a long period of time, such as machine parts such as automobile parts. To improve the reliability of these parts, resin molding is performed. It has been strongly desired to improve the long-term heat resistance of products.

As a general method for improving the heat resistance of polyamide, a method of blending various stabilizers with polyamide is known. For example, Japanese Patent Laid-Open Nos. 2-212533 and 2-214752
No. 2-173059 and No. 62-273256, etc.
Polyamide 66, Polyamide (ε-caprolactam) /
A polyamide resin composition in which an aliphatic polyamide such as 66 is blended with a specific phenol-based stabilizer, sulfur-based stabilizer and phosphorus-based stabilizer, respectively, is disclosed. However, the main resin constituting the compositions disclosed in these publications is an aliphatic polyamide, and it is known that the melting point of this aliphatic polyamide is considerably lower than that of the aromatic polyamide. Even if an attempt is made to improve the heat resistance by blending a stabilizer compounded with an aliphatic polyamide in a polyamide having a high melting point such as an aromatic polyamide as described in the above publication, since the melting point of the aromatic polyamide is high, It has been found that the stabilizer foams during the production of the compound or during molding.

Further, JP-A-57-123254 discloses a composition comprising a polyamide, a specific phenolic stabilizer, a sulfur stabilizer and a copper compound. However, in this composition, the copper compound is an essential component for exhibiting sufficient heat aging resistance, and by using this copper compound in combination with a specific phenol-based stabilizer and sulfur-based stabilizer, Although the heat resistance stability is improved, on the other hand, a copper compound added as a stabilizer may cause metal damage. Particularly, when metallic copper released from the above-mentioned copper compound is mixed in the composition, various characteristics such as electric characteristics of the resin may change. Further, this resin composition also has a problem that foaming is caused during the production of the compound and during the molding, similarly to the above. That is, the stabilizer formulation used in the conventional aliphatic polyamide,
It was not always satisfactory as a stabilizer formulation for polyamides with high melting points, especially aromatic polyamides.

[0007]

The object of the present invention is to prevent the resin composition from foaming due to the heating in the steps of preparing a compound and manufacturing a molded body, further, having no metal damage, and having no gas burning during molding. Moreover, it is an object of the present invention to provide a thermoplastic resin composition capable of producing a molded article excellent in heat resistance, low water absorption and thermal aging resistance, and a molded article made of this thermoplastic resin composition.

[0008]

SUMMARY OF THE INVENTION The thermoplastic resin composition of the present invention (first)
Is (A) a polyamide having a melting point of 280 ° C. or higher, (B)
A hindered phenolic antioxidant having a molecular weight of 500 or more and a 10% weight loss temperature of 300 ° C. or more in a thermogravimetric analysis curve measured in air, and (C) a molecular weight of 600 or more and in air It is characterized by comprising a sulfur-based antioxidant having a 10% weight loss temperature of 280 ° C. or higher in the measured thermogravimetric analysis curve.

Particularly in the present invention, the aromatic polyamide (A) includes (A-1) terephthalic acid component unit 5
A dicarboxylic acid component unit consisting of 0 to 100 mol% and an aromatic dicarboxylic acid component unit other than terephthalic acid 0 to 50 mol% and / or an aliphatic dicarboxylic acid component unit having 4 to 20 carbon atoms And a repeating unit consisting of an aliphatic diamine component unit and / or an alicyclic diamine component unit and a diamine component unit, and has an intrinsic viscosity of 0.
Aromatic polyamides in the range of 5 to 3.0 dl / g and having a melting point above 300 ° C. are preferred. In this case, the sulfur-based antioxidant (C) is preferably a sulfur-based stabilizer represented by the following formula [III].

(R ¹ S—R ² —COOCH ₂ ) ₄ C ... [III] However, in the above formula [III], R ¹ has 3 carbon atoms.
Represents a hydrocarbon group of 20 to 20 and R ² has 1 to 5 carbon atoms.
Represents a divalent hydrocarbon group of (second thermoplastic resin composition). Furthermore, the molded product of the present invention is characterized by comprising the above-mentioned thermoplastic resin composition.

The first thermoplastic resin composition of the present invention is a polyamide (A) having a melting point of 280 ° C. or higher, a molecular weight of 500 or higher, and a 10% weight loss temperature of 300 in a thermogravimetric analysis curve measured in air. Hindered phenolic antioxidant (B) having a temperature of ℃ or more, and 1 in the thermogravimetric analysis curve having a molecular weight of 600 or more and measured in air.
A resin composition comprising a sulfur-based antioxidant (C) having a 0% weight loss temperature of 280 ° C. or higher. By having such a composition, it does not foam even by heating when preparing the compound, has no metal damage, does not have gas burning during molding, and has heat resistance, low water absorption and heat aging resistance. It is possible to obtain a resin composition capable of molding an excellent molded body.

A second thermoplastic resin composition of the present invention is the same as the first thermoplastic resin composition, wherein the specific aromatic polyamide (A-1) is used as the polyamide (A), and the sulfur-based As the stabilizer, the specific compound represented by the above formula is used. With such a composition, it is possible to further improve the heat aging resistance and obtain a resin composition capable of molding a molded body with less gas burning.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Next, the thermoplastic resin composition of the present invention will be specifically described. The first thermoplastic resin composition of the present invention comprises a polyamide (A) having a specific melting point or higher, a specific hindered phenol-based antioxidant (B) and a sulfur-based antioxidant (C).

The polyamide (A) constituting the composition of the present invention is a polyamide having a melting point of 280 ° C or higher, preferably more than 300 ° C and 340 ° C or less. Thus, the melting point is 280 ° C or higher, preferably more than 300 ° C and 340
By using a polyamide having a temperature of ℃ or less, the heat aging resistance of the molded article obtained from the composition of the present invention becomes good.

Polyamide (A) having such a melting point
Include a polyamide formed from a diamine and a dicarboxylic acid, and a copolyamide resin formed from a diamine, a dicarboxylic acid, and aminocaproic acid or a lactam.
Examples of diamines used here are 1,4-diaminobutane, 1,6-diaminohexane, 1,9-diaminononane,
Aliphatic diamines such as 1,10-diaminodecane, 1,12-diaminododene, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-bis (aminomethyl) Alicyclic diamines such as cyclohexane, 1,4-bis (aminomethyl) cyclohexane and bis (p-aminocyclohexylmethane), and aromatic diamines such as m-xylylenediamine and p-xylylenediamine. Can be mentioned.

Examples of dicarboxylic acids are aliphatic dicarboxylic acids such as adipic acid, suberic acid, dodecanedicarboxylic acid and sebacic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, terephthalic acid,
Mention may be made of aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, naphthalenedicarboxylic acid and diphenyldicarboxylic acid.

Further, examples of aminocaproic acid or lactams include ε-caprolactam and aminocaproic acid. Specific examples of the polyamide having a melting point of 280 ° C. or higher, which is produced from the diamine, dicarboxylic acid, aminocaproic acid, or lactam, specifically include polyamide 46, polyamide 6T,
Polyamide 6TI, Polyamide 6T6, Polyamide 6T
I10, polyamide MXD6, polyamide PXD6, polyamide (6T / 6) and the like can be mentioned. These polyamides may be used alone or in combination of two or more.

The polyamide (A) having a melting point of 280 ° C. or higher used in the present invention includes nylon 66 and nylon 6
Polyamides having a melting point of less than 280 ° C. may be mixed. In this case, the amount of each mixture is adjusted so that the melting point of the mixture is 280 ° C. or higher. The intrinsic viscosity [η] of the above polyamide (A) measured at a temperature of 30 ° C. in concentrated sulfuric acid is usually 0.5 to 3.0 dl / g, preferably 0.5 to 2.8 dl / g, Particularly preferably, it is 0.6 to 2.5.
It is in the range of dl / g.

The polyamide constituting the thermoplastic resin composition of the present invention is a polyamide (A) having a melting point of 280 ° C. or higher as described above, but in the present invention, it is described below among the above polyamides (A). Aromatic polyamide (A
By using -1), a composition having extremely excellent thermal stability can be obtained. The aromatic polyamide (A-1) constituting the polyamide resin composition of the present invention comprises a specific dicarboxylic acid component unit [a] and a specific aliphatic diamine component unit or alicyclic diamine component unit [b]. It is composed of repeating units consisting of.

The specific dicarboxylic acid component unit [a] constituting this polyamide has a terephthalic acid component unit (a-1) as an essential component unit. The repeating unit having such a terephthalic acid component unit (a-1) is represented by the following formula [Ia]
Can be represented by.

[0021]

[Chemical 1]

[Ia] However, in the above formula [Ia], R ¹ is a divalent aliphatic or alicyclic hydrocarbon group, preferably an alkylene having 4 to 18 carbon atoms. Represents a group. The dicarboxylic acid component unit [a] does not need to be all the component units represented by the above [I-a], and the terephthalic acid component unit as described above can be used.
Part of (a-1) may be another dicarboxylic acid component unit.

The carboxylic acid component unit other than the terephthalic acid component includes an aromatic dicarboxylic acid component unit (a-2) other than terephthalic acid and an aliphatic dicarboxylic acid component unit (a-3). Examples of the aromatic dicarboxylic acid component unit (a-2) other than terephthalic acid include an isophthalic acid component unit, a 2-methylterephthalic acid component unit and a naphthalenedicarboxylic acid component unit. An isophthalic acid component unit is particularly preferable as a component unit in which the aromatic polyamide constituting the composition of the present invention is derived from an aromatic dicarboxylic acid other than terephthalic acid.

Among the aromatic dicarboxylic acid component units (a-2) other than terephthalic acid, the repeating unit having an isophthalic acid component unit particularly preferred in the present invention is represented by the following formula [Ib]. it can.

[0025]

[Chemical 2]

[Ib] In the above formula [Ib], R ¹ is a divalent aliphatic or alicyclic hydrocarbon group, preferably 4 carbon atoms.
~ 18 alkylene groups are represented. The aliphatic dicarboxylic acid component unit (a-3) is usually derived from an aliphatic dicarboxylic acid having an alkylene group having 4 to 20 carbon atoms, preferably 6 to 12 carbon atoms. Examples of the aliphatic dicarboxylic acid used for deriving such an aliphatic dicarboxylic acid component unit (a-3) include succinic acid, adipic acid, azelaic acid and sebacic acid.

As the aliphatic dicarboxylic acid component unit, an adipic acid component unit and a sebacic acid component unit are particularly preferable. A repeating unit having an aliphatic dicarboxylic acid component unit (a-3) as another dicarboxylic acid component unit constituting the dicarboxylic acid component unit [a] can be represented by the following formula [II].

[0028]

[Chemical 3]

[II] However, in the above formula [II], R ¹ has the same meaning as described above, and n represents an integer of usually 2 to 18, preferably 4 to 10. A diamine component unit [b] that forms an aromatic polyamide (A-1) with the dicarboxylic acid component unit.
Can be derived from aliphatic alkylenediamines and alicyclic diamines having 4 to 18 carbon atoms.

Specific examples of such an aliphatic alkylenediamine include 1,4-diaminobutane, 1,6-diaminohexane, trimethyl-1,6-diaminohexane, 1,7-diaminoheptane, 1, Mention may be made of 8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane and 1,12-diaminododecane. Further, as a specific example of the alicyclic diamine, diaminocyclohexane can be mentioned.

Particularly in the present invention, the diamine component unit is preferably a component unit derived from a linear aliphatic alkylenediamine, and such a linear aliphatic alkylenediamine includes 1,6-diaminohexane and 1,8 -Diaminooctane, 1,10-diaminodecane, 1,12-diaminododecane and mixtures thereof are preferred. Furthermore, among these, 1,6-diaminohexane is particularly preferable.

The aromatic polyamide (A used in the present invention
-1) All dicarboxylic acid components constituting (100 mol%)
The content rate of terephthalic acid component unit (a-1) is 50
˜100 mol%, preferably 50-80 mol%,
Aromatic dicarboxylic acid component unit (a-2) other than terephthalic acid
Content of 0 to 50 mol%, preferably 0 to 30 mol%
And the content of the aliphatic dicarboxylic acid component unit (a-3) is 0 to 50 mol%, preferably 0 to 20 mol%.

The aromatic polyamide (A-1)
Is a terephthalic acid component unit which is the above-mentioned main component unit as an aromatic dicarboxylic acid component unit, and a component unit derived from a divalent aromatic carboxylic acid other than terephthalic acid represented by an isophthalic acid component unit and the above In addition to the repeating unit having the aliphatic dicarboxylic acid component unit, a small amount of a component unit derived from a tribasic or higher polyvalent carboxylic acid such as trimellitic acid or pyromellitic acid may be contained. In the aromatic polyamide (A-1) that constitutes the composition of the present invention, the component unit derived from such a polyvalent carboxylic acid is usually contained in an amount of 0 to 5 mol%.

Further, the aromatic polyamide (A-1) is
A mixture of an aromatic polyamide containing a repeating unit represented by the formula [Ia] as a main repeating unit and an aromatic polyamide containing a repeating unit represented by the formula [Ib] as a main repeating unit Good. In this case, the formula [I-
The content of the aromatic polyamide containing the repeating unit represented by a] as a main repeating unit is usually 50% by weight or more, preferably 60% by weight or more.

The intrinsic viscosity [η] of the above aromatic polyamide (A-1) measured in concentrated sulfuric acid at a temperature of 30 ° C.
Is usually 0.5-3.0 dl / g, preferably 0.5-2.
It is in the range of 8 dl / g, particularly preferably 0.6 to 2.5 dl / g. The aromatic polyamide (A-1) has a higher melting point than the conventionally used aliphatic polyamide. That is, this aromatic polyamide (A-1) is usually 300
It has a melting point above ℃, this melting point is preferably 3
Within the range of 05 to 340 ° C, more preferably 310 to 3
The composition containing the aromatic polyamide (A-1) in the range of 40 ° C. has particularly excellent heat resistance. Furthermore, the glass transition temperature in the amorphous part of this aromatic polyamide (A-1) is usually 80 ° C. or higher. By using the aromatic polyamide having the melting point and the glass transition temperature of the amorphous portion within the above range, the resin is unlikely to be in a molten state even when the molded body is exposed to high temperature.
Despite having the above characteristics, the aromatic polyamide (A-1) is excellent in moldability. Further, since this aromatic polyamide (A-1) has a glass transition temperature of 80 ° C. or higher in the amorphous portion, its dimensional change does not easily occur even when the molded body is exposed to high temperature.

Since this aromatic polyamide has a specific structure, it exhibits a low value for water absorption, which has been a problem of conventional aliphatic polyamides. In the present invention, the aromatic polyamide (A-1) may be used alone as the polyamide (A) having a melting point of 280 ° C. or higher, and the aromatic polyamide (A-1) and other polyamides (A It can be used in combination with A).

The thermoplastic resin composition of the present invention contains the above polyamide (A) and a specific hindered phenol-based antioxidant and sulfur-based antioxidant. Hindered phenolic antioxidant used in the present invention (B)
Has a molecular weight of 500 or more, preferably 540 or more, more preferably 600 or more. Furthermore, this hindered phenolic antioxidant (B) has a 10% weight loss temperature (TG
A10% weight loss temperature) is 300 ° C or higher, preferably 320
℃ or more, more preferably 350 ℃ or more.

In the present invention, the thermogravimetric analysis curve was measured by using a thermal analyzer TG-DTA manufactured by Rigakudenki Co., Ltd.
The curve obtained by measurement under the measurement conditions of the temperature rising rate of 0 ° C./min. There are various types of phenolic antioxidants other than hindered phenolic antioxidants, but using phenolic antioxidants other than hindered phenolic antioxidants improves the heat resistance of the molded product sufficiently. do not do.

Further, even a hindered phenolic antioxidant has a molecular weight of less than 500 ° C. or a hindered temperature of 10% weight loss in a thermogravimetric analysis curve measured in air of less than 300 ° C. The phenolic antioxidant is decomposed by heating during preparation of the compound or during production of the molded body, so that the oxidative stabilizing function of the composition is lost. Further, since foaming occurs in the composition due to the decomposition of the antioxidant due to such heating, defects are likely to occur in the molded body.

As an example of the hindered phenolic antioxidant having such characteristics, n-octadecyl-3- (4 '
-Hydroxy-3 ', 5'-di-tert-butylphenyl) propionate: (molecular weight 530, TGA 10% weight loss temperature 305 ° C),
1,1,3-Tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane: (molecular weight 544, 10% weight loss temperature 32
3 ° C), 1,3,5-trimethyl-2,4,6-tris (3,5, -di-ter
t-Butyl-4-hydroxyphenyl) benzylbenzene:
(Molecular weight 774, TGA 10% weight loss temperature 338 ° C), 1,3,5-tris (4-hydroxy-3,5-di-tert-butylbenzyl) -s-
Triazine-2,4,6- (1H, 3H, 5H) -trione: (molecular weight 78
3, TGA10% weight loss temperature 347 ℃), ethylene glycol-
Bis [3,3-bis (3'-tert-butyl-4'-hydroxyphenyl) butyrate]: (molecular weight 794, TGA 10% weight loss temperature 3
44 ° C.), tetrakis [methylene-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane:
(Molecular weight 1176, TGA 10% weight loss temperature 355 ° C), 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl]
2,4,8,10-Tetraoxaspiro [5,5] undecane: (Molecular weight 741, TGA10% weight loss temperature 372 ° C), 1,6-hexanediol-bis [3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate]: (molecular weight 639, TGA10%
Weight loss temperature 314 ° C), triethylene glycol-bis [3
-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate]: (molecular weight 587, TGA 10% weight loss temperature 31
1 ℃), N, N'-hexamethylenebis (3,5-di-tert-butyl
-4-hydroxycinnamamide): (molecular weight 637, TGA
10% weight loss temperature 330 ° C), N, N'-bis [3- (3,5-di-tert-
Butyl-4-hydroxyphenyl) propionyl] hydrazine: (molecular weight 553, TGA 10% weight loss temperature 304 ° C.), 2,
2'-oxamido-bis-ethyl-3 (3,5-di-tert-butyl-4-
Hydroxyphenyl) propionate: (Molecular weight 69
7, TGA10% weight loss temperature 323 ° C), 2,2'-methylene-bis (4-methyl-6-tert-butylphenol) terephthalate: (molecular weight 810, TGA10% weight loss temperature 327 ° C), 1,3,
5-Tris [(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate:
(Molecular weight 1045, TGA 10% weight loss temperature 346 ° C), and
2,2-bis [4- {2- (3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy)} ethoxyphenyl] propane: (molecular weight 836) can be mentioned.

These compounds can be used alone or in combination. Among such hindered phenolic antioxidants, bifunctional or higher functional phenols are preferable, and 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy } -1,
1-dimethylethyl] 2,4,8,10-tetraoxaspiro [5,
5] Undecane, N, N'-hexamethylenebis (3,5-di-tert
-Butyl-4-hydroxycinnamamide), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane and n-octadecyl-3- (4'-hydroxy-3 ' , 5'-J
Particularly preferred is -tert-butylphenyl) propionate.

In the resin composition of the present invention, a specific sulfur-based antioxidant is blended together with the above-mentioned hindered phenol-based antioxidant. The sulfur-based antioxidant (C) used in the present invention has a molecular weight of 600 or more, preferably 620 or more, more preferably 650 or more. Furthermore, the 10% weight loss temperature in the thermogravimetric analysis curve (TGA) of this sulfur-based antioxidant (C) measured in air is 280 ° C. or higher, preferably 290 ° C. or higher, and more preferably 300 ° C. or higher.

Even sulfur type antioxidants have a molecular weight of 6
Sulfur-based antioxidants that are less than 00 ° C or have a 10% weight loss temperature of less than 280 ° C in a thermogravimetric analysis curve measured in air are heated at the time of preparing a compound or when manufacturing a molded body. As a result, the oxidative stability function of the composition is lost. Further, since foaming occurs in the composition due to the decomposition of the antioxidant due to such heating, defects are likely to occur in the molded body.

In the present invention, the compound represented by the following formula [III] is preferably used as the sulfur antioxidant. ^{(R 1 S-R 2 -COOCH} 2) 4 C ··· [III] In the above formula [III], R ¹ is typically 3 carbon atoms
It represents 20, preferably 5 to 20 hydrocarbon groups. Also,
R ² usually represents a divalent hydrocarbon group having 1 to 5 carbon atoms, preferably 1 to 3 carbon atoms. The four sulfur-containing groups bonded to the carbon atom may be the same or different.

Specific examples of the compound represented by the above formula [III] include penta (erythrityl-tetra-β-mercaptolauryl) propionate: (molecular weight 1160,
TGA 10% weight loss temperature 300 ° C.) can be mentioned. In addition to the compound represented by the above formula [III], a compound represented by the following formula [IV] can be used as the sulfur-based antioxidant.

S (R ⁴ —COOR ³ ) ₂ ... [IV] However, in the above formula [IV], R ³ usually represents an alkyl group having 15 to 30 carbon atoms, preferably 18 to 30 carbon atoms. , R ³ may contain a sulfur atom. R ⁴ represents a divalent aromatic group which may have an alkyl group, a divalent alicyclic alkyl group which may have an alkyl group, a divalent alkyl group, or a single bond.

Specific examples of the compound represented by the above formula [IV] include distearylthio-di-1,1'-methylpropionate: (molecular weight 696, TGA 10% weight loss temperature 296
° C), myristyl stearyl thiodipropionate:
(Molecular weight 626, TGA 10% weight loss temperature 284 ° C), distearyl thiodipropionate: (Molecular weight 682, TGA 10% weight loss temperature 292 ° C), and distearyl thiodibutyrate: (Molecular weight 710, TGA 10% weight loss temperature 296 ° C) Can be mentioned.

In the present invention, among the above sulfur-based antioxidants (C), penta (erythrityl-tetra-β-
It is preferred to use mercaptolauryl) propionate and stearyl thiodipropionate, alone or in combination. Especially as polyamide (A),
When the above-mentioned specific aromatic polyamide (A-1) is used, the compound represented by the above formula [III] is suitable as the sulfur-based antioxidant. That is, since the above aromatic polyamide (A-1) has a relatively high melting point, it is necessary that the heat resistance of the sulfur-based antioxidant used is also high. The compound is less likely to be decomposed even when heated during the production of the compound from the above aromatic polyamide (A-1) or during the production of the molded body, and therefore foaming or the like is not caused by the heating. Thus, by using a composition comprising a specific aromatic polyamide, a specific hindered phenolic antioxidant, and a sulfur-based antioxidant, it does not foam during compounding and has no metal damage. ,
It is possible to produce a molded product which is free from gas burning during molding and which is particularly excellent in heat resistance, low water absorption and heat aging resistance.

In the resin composition of the present invention, the hindered phenol type antioxidant (B) and the sulfur type antioxidant (C) are usually used in an amount of 0.1 parts by weight per 100 parts by weight of the resin component.
It is compounded in an amount within the range of 2 to 4 parts by weight. Further 0.5
It is preferably about 2 parts by weight. Further, the hindered phenol antioxidant (B) and the sulfur antioxidant (C) in the resin composition of the present invention are 1: 5 to 5: 1.
The weight ratio is within the range. Further 1: 3-3.
It is preferably within the range of 5: 1, particularly 1: 1 to 3: 1.

The thermoplastic resin composition of the present invention contains an inorganic filler (material), an organic filler (material), a heat stabilizer, a weather resistance stabilizer, and an antistatic agent as long as the characteristics are not impaired. , Anti-slip agent, anti-blocking agent, anti-fog agent,
Additives such as lubricants, pigments, dyes, natural oils, synthetic oils and waxes may be added. Suitable examples of the fiber used as the inorganic filler include glass fiber, carbon fiber and boron fiber. As such a fibrous filler (material), glass fiber is particularly preferable. By using glass fibers, the moldability of the composition is improved, and at the same time, the mechanical properties of the connector such as tensile strength, flexural strength, flexural modulus, and heat resistance properties such as heat distortion temperature are improved. The average length of the glass fibers as described above is usually 0.1 to 20 mm, preferably 0.3 to 6 mm.
And the aspect ratio is usually 10-200.
It is 0, preferably in the range of 30 to 600. It is preferable to use glass fibers having an average length and aspect ratio within such a range. Such fiberglass is
The amount is usually 200 parts by weight or less, preferably 5 to 180 parts by weight, and more preferably 5 to 150 parts by weight with respect to 100 parts by weight of the resin component.

In addition to the above-mentioned inorganic fibrous filler (material), in the present invention, powdery, granular, plate-like, needle-like, cloth-like,
Various fillers having a shape such as a mat can be used. Examples of such fillers include silica, silica alumina, alumina, titanium dioxide, talc, diatomaceous earth, clay, kaolin, glass, mica, gypsum, red iron oxide and powdered or plate-like inorganic compounds such as zinc oxide, Needle-like inorganic compounds such as potassium titanate, polyparaphenylene terephthalamide, polymetaphenylene terephthalamide, polyparaphenylene isophthalamide, polymetaphenylene isophthalamide, condensates of diaminodiphenyl ether and terephthalic acid (or isophthalic acid), and Wholly aromatic polyamide such as a condensate of para (meth) aminobenzoic acid; wholly aromatic polyamideimide such as a condensate of diaminodiphenyl ether and trimellitic anhydride or pyromellitic anhydride; wholly aromatic polyester, wholly aromatic Polyimide, heterocyclic ring-containing compounds such as polybenzimidazole and poly imidazo phenanthroline; and such as polytetrafluoroethylene and the like. These can be used in the form of powder, plate, fiber or cloth.

Among these fillers, it is preferable to use a powdery filler, especially talc. Two or more kinds of these fillers can be mixed and used. Further, these fillers may be treated with a silane coupling agent or a titanium coupling agent before use. The average particle size of such powdery filler is usually in the range of 0.1 to 200 μm, preferably 1 to 100 μm.

Such a powdery filler is usually used in an amount of 200 parts by weight or less, preferably 100 parts by weight or less, particularly preferably 0.1 part by weight, based on 100 parts by weight of the resin component in the composition. Used in an amount of 5 to 50 parts by weight. Further, a heat-resistant resin can be added to the composition within a range that does not impair the characteristics. Examples of such heat resistant thermoplastic resins include PPS (polyphenylene sulfide), PPE (polyphenylene ether), PES (polyether sulfone), PEI (polyether imide) and LCP (liquid crystal polymer). Further, modified products of these resins can be mentioned. Especially in the present invention, polyphenylene ether and polyphenylene sulfide are preferable. The content of such heat-resistant thermoplastic resin is usually less than 50% by weight,
It is preferably 0 to 40% by weight.

The thermoplastic resin composition of the present invention comprises an aromatic polyamide (A), a specific hindered phenol-based antioxidant (B) and a specific sulfur-based antioxidant (C), and if necessary, various fillers. Can be manufactured by mixing and kneading. The kneading temperature at this time is set to a temperature equal to or higher than the melting point of the resin component. A known melt-kneading device can be used for kneading.

The specific polyamide (A) as described above,
The thermoplastic resin composition of the present invention comprising the above specific hindered phenol-based antioxidant (B) and sulfur-based antioxidant (C) does not foam when the compound is prepared and has metal damage. No gas burning during molding, and
The molded product obtained from this composition is characterized by being excellent in heat resistance, low water absorption and heat aging resistance.

The heat distortion temperature (heat distortion temperature, load: value measured at 18.6 kg) of the thermoplastic resin composition having such a composition is usually 70 to 150 ° C., preferably 80 to 150 ° C.
It is in the range of 120 ° C. and exhibits extremely high heat resistance while being thermoplastic. The specific gravity of this resin composition is usually 1.05 to 1.12, and in most cases 1.08 to 1.10.
Compared with the fact that polybutylene terephthalate, which is relatively widely used as a thermoplastic resin for molding, is about 1.31 and nylon 66 is about 1.14, it is formed from the above resin composition. The molded product is lightweight.

Using the thermoplastic resin composition prepared as described above, a usual melt molding method such as compression molding method,
By using an injection molding method, an extrusion molding method, or the like, a molded body having a desired shape can be manufactured. For example, the resin composition of the present invention has a cylinder temperature of 280 to 280.
It is possible to manufacture a molded product by introducing it into an injection molding machine prepared at about 350 ° C. to bring it into a molten state and introducing it into a mold having a predetermined shape.

In the resin composition of the present invention, by combining the resin and the antioxidant as described above, an excellent effect of improving heat aging resistance which is not seen when an aliphatic polyamide such as nylon 66 is used is obtained. Can be seen. There is no particular limitation on the shape of the molded body produced using the thermoplastic resin composition of the present invention, for example, electric tools and general industrial parts, mechanical parts such as gears and cams, and,
It can be used as a resin for forming electronic parts such as a printed wiring board and a housing for electronic parts. Furthermore, the resin composition of the present invention is also suitable as a resin for forming automobile interior / exterior parts, engine room parts, automobile electrical parts, and the like. In particular, the thermoplastic resin composition of the present invention is highly useful as a resin for producing a connector for interconnecting electronic circuits. That is, a connector prepared by using the resin composition as described above using, for example, an injection molding machine has excellent heat resistance, and less deterioration in toughness after the connector is once heated. .. Recently, electronic parts equipped with such a connector are often soldered by an infrared reflow method or the like, and the conventional connector is that the toughness of the connector is deteriorated by heating by infrared reflow or the like. There is. Since the elongation rate of the connector decreases as the toughness decreases, the connecting work (fitting work) between the connectors may not be performed smoothly. Further, in the case where the connector is used in the engine room of a car, the toughness is lowered by heating and the durability of the connector is lowered. The connector produced by using the thermoplastic resin composition of the present invention is less likely to have a decrease in toughness as described above, and the required elongation can be maintained even by heating. Therefore, the connectors can be easily connected to each other and the durability is improved.

[0059]

The thermoplastic resin composition of the present invention comprises a polyamide (A) having a specific melting point, a specific hindered phenolic antioxidant (B) and a sulfuric antioxidant (C). To do. Thus, by mixing the above specific hindered phenol-based antioxidant (B) and sulfur-based antioxidant (C) with the high-melting polyamide (A), the antioxidant is heated by heating during the production of the compound. Does not decompose, and therefore the resin does not foam during the production of the compound or the production of the molded body. Furthermore, since the antioxidant used in the present invention does not contain a metal, it does not cause metal damage. Also,
The above specific hindered phenol-based antioxidant (B) and sulfur-based antioxidant (C) can impart extremely excellent properties to the polyamide (A), and there is no gas burning during molding, In addition, it is possible to manufacture a molded product having excellent heat resistance, low water absorption and heat aging resistance.

[0060]

EXAMPLES The present invention will now be described in more detail by showing Examples of the present invention, but the present invention should not be construed as limited by these Examples. (A-1) and (A) described below as starting material polyamides
-2) was used. -Aromatic polyamide (A-1): 1,
Aromatic polyamide resin consisting of 6-diaminohexane, terephthalic acid and adipic acid. The molar ratio of terephthalic acid to adipic acid is 55:45.

The physical properties of the aromatic polyamide (A-1) are as follows. Intrinsic viscosity (measured in concentrated sulfuric acid at 30 ° C): 1.6 dl / g, amino group content: 0.037 meq / g (titration value with paratoluenesulfonic acid in meta-cresol solution) Melting point ...・ 312 ° C glass transition temperature ・ ・ ・ 80 ° C ・ Aliphatic polyamide (A-2): nylon 66 intrinsic viscosity (measured in concentrated sulfuric acid at 30 ° C) ・ ・ ・ 1.26 dl / g, amino group content ・ ・ ・ 0 0.038 meq / g (Titration value with para-toluenesulfonic acid in meta-cresol solution) Melting point: 366 ° C Glass transition temperature: 53 ° C Hindered phenol antioxidant As a hindered phenol antioxidant , Table 1 below
The compounds (B-1) to (B-4) described in 1 above were used. Table 1 also shows the molecular weight of this compound and TGA 10%.
Also list the weight loss.

[0062]

[Table 1]

-Sulfur-based antioxidant The sulfur-based antioxidant is described in Table 2 below (C-
The compounds of 1) to (C-3) were used. Table 2 also shows the molecular weight of this compound and TGA 10% reduction.

[0064]

[Table 2]

-Phosphorus stabilizer The following compounds were prepared as phosphorus stabilizers.
Bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite.

[0066]

Examples 1 to 6 and Comparative Examples 1 to 6 Polyamides, hindered phenolic antioxidants shown in Table 1 above, and Table 2
The sulfur-based antioxidant shown in Table 1 was mixed in the amounts shown in Table 3 and melt-kneaded in a twin-screw extruder to pelletize. The twin-screw extruder used was PCM-45 manufactured by Ikegai Tekko KK and the cylinder temperature was set to 320 ° C. A molded body was manufactured by injection molding using the pellets thus obtained.

Separately, injection-molded test pieces were prepared using the pellets thus obtained, and the following items were measured for the test pieces. Tensile Strength (TS): Measured according to ASTM-D-638. Elongation at break (EL): measured by ASTM-D-638. Izod impact strength: Measured according to ASTM-D-256. Measurement temperature 23 ℃, with notch.

Bending strength: Measured according to ASTM-D-790. Flexural modulus: Measured according to ASTM-D-790. Heat Deflection Temperature (HDT): Measured by ASTM-D-648. Furthermore, in order to evaluate the heat aging resistance, the test piece was heated to 150 ° C.
After annealing at 200 ° C. for 200 hours, TS and EL were measured by the above measuring method.

The results are shown in Table 4.

[0070]

[Table 3]

[0071]

[Table 4]

Continuation of the front page (72) Inventor Yoshikazu Amimoto 6-1-2 Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture Mitsui Petrochemical Industry Co., Ltd. Mori Petrochemical Industry Co., Ltd.

Claims (5)

[Claims] 1. A polyamide having a melting point of 280 ° C. or higher, (B) a molecular weight of 500 or higher, and a 10% weight loss temperature of 300 ° C. or higher in a thermogravimetric analysis curve measured in air. A thermoplastic resin comprising an antioxidant and (C) a sulfur-based antioxidant having a molecular weight of 600 or more and having a 10% weight loss temperature of 280 ° C. or more in a thermogravimetric analysis curve measured in air. Resin composition. 2. The total compounding amount of the hindered phenol antioxidant (B) and the sulfur antioxidant (C) per 100 parts by weight of the polyamide (A) is within the range of 0.2 to 4 parts by weight. And the compounding weight ratio of the hindered phenol-based antioxidant (B) and the sulfur-based antioxidant (C) is 1:
A first range of 5 to 5: 1.
The thermoplastic resin composition according to item. 3. A polyamide (A) having a melting point of 280 ° C. or higher.
Is (A-1) terephthalic acid component unit 50 to 100 mol%
And an aromatic dicarboxylic acid component unit other than terephthalic acid 0
To 50 mol% and / or 0 to 50 mol% of an aliphatic dicarboxylic acid component unit having 4 to 20 carbon atoms, and an aliphatic diamine component unit and / or an alicyclic diamine component unit. It is composed of repeating units consisting of diamine component units and has an intrinsic viscosity of 0.5-3.0 dl / g measured in concentrated sulfuric acid at 30 ° C.
3. The thermoplastic resin composition according to claim 1, which is an aromatic polyamide having a melting point of more than 300 ° C. 4. The sulfur-based antioxidant (C) has the formula [II
The thermoplastic resin composition as in claim 1 wherein or third term, wherein the sulfur type stabilizer represented by ^{I]; (R 1 S-} R 2 -COOCH 2) 4 C ··· [ III] [In the above formula [III], R ¹ has 3 to 20 carbon atoms.
And a hydrocarbon group of R ² represents a divalent hydrocarbon group having 1 to 5 carbon atoms]. 5. A resin molding comprising the thermoplastic resin composition according to any one of claims 1 to 4.