JPH0741657A - Resin composition - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] To provide a resin composition having remarkably improved thermal stability during molding and heat deterioration resistance when used in a high temperature atmosphere. [Structure] (A) Polyphenylene ether resin 30 to 7
0 parts by weight, (B) polyamide 70 to 30 parts by weight, (C)
0.1 to 5 parts by weight of a di- or tricarboxylic acid having 3 to 6 carbon atoms, (D) N, N'-hexamethylene bis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 2 , 4-bis- (n-octylthio) -6-
(4-Hydroxy-3,5-di-tertiary butyrianilino) -1,3,5-triazine, pentaerythritol-tetrakis- [3- (3,5-di-tertiary-
Butyl-4-hydroxyphenyl) -propionate], zinc oxide, zinc sulfide, 0.01 to 3 parts by weight of one or more antioxidants, (E) impact modifier 1 to 20
A resin composition consisting of parts by weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the appearance, mechanical properties, dimensional accuracy, and molding accuracy of a molded article by melt-kneading PPE, polyamide, a specific compound and a specific antioxidant by a specific method. PPE / polyamides that have significantly improved weldability, thermal stability during molding, and heat deterioration resistance when used in high-temperature atmosphere, without impairing fluidity (hereinafter abbreviated as fluidity), solvent resistance, and oil resistance. Regarding the resin composition, the resin composition of the present invention can be used in a wide variety of fields such as electric / electronic parts, automobile parts, machine parts, building parts, and sundries.

[0002]

2. Description of the Related Art Conventionally, a composition comprising PPE and a styrene resin is excellent in electrical properties, mechanical properties, hot water resistance, dimensional accuracy, moldability, etc.
It is used in a wide range of fields such as automobile parts, machine parts, and sundries. However, the composition comprising PPE and styrene resin has a heat deterioration resistance when used in a high temperature atmosphere,
Since the solvent resistance and oil resistance are insufficient, improvement has been strongly desired.

Japanese Patent Publication No. 60-11966 and Japanese Patent Laid-Open No. 6-6
JP-A-2-273256 discloses (A) PPE, (B) polyamide, in order to improve solvent resistance and oil resistance.
(C) In the molecule, (a) carbon-carbon double bond or carbon-carbon triple bond and (b) carboxylic acid group, acid anhydride group, acid amide group, imide group, carboxylic acid ester group, epoxy group, amino A method for producing a modified polymer is disclosed, which comprises melt-kneading a compound having a group or a hydroxyl group at the same time.

In JP-A-62-138553, carboxylated PP is prepared by melt-mixing a mixture essentially consisting of PPE and an ethylenically unsaturated carboxyl compound.
E, and then melt-treating the carboxylated PPE in the presence of polyamide, an improved process for blending the polyamide and PPE is disclosed, which comprises the addition of antioxidants, stabilizers, etc. It is disclosed that further modifications can be made. However,
It was found that the addition of ordinary antioxidants and stabilizers to the composition of carboxylated PPE and polyamide does not necessarily have any effect.

[0005]

The problems to be solved by the present invention are to solve the problems such as weld strength and molding without deteriorating the appearance, mechanical properties, dimensional accuracy, solvent resistance, oil resistance and fluidity of molded products. Another object of the present invention is to provide a PPE / polyamide resin composition having significantly improved thermal stability during use and heat deterioration resistance when used in a high temperature atmosphere.

[0006]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above problems and completed the present invention. That is, the present invention relates to (A) polyphenylene ether resin (hereinafter abbreviated as PPE) 30 to 70 parts by weight, (B) polyamide 70 to 30 parts by weight, (C) C 3 to C 6 di- or tricarboxylic acid 0.1. ˜5 parts by weight, (D) N, N′-hexamethylene bis (3,5-di-tert-butyl-
4-hydroxy-hydrocinnamide), 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,
5-di-tertiary butyrianirino) -1,3,5-
Triazine, pentaerythritol-tetrakis- [3
-(3,5-di-tertiary-butyl-4-hydroxyphenyl) -propionate], zinc oxide, 0.01 to 3 parts by weight of one or more antioxidants selected from zinc sulfide,
(E) A resin composition comprising 1 to 20 parts by weight of an impact modifier, wherein (A) PPE and (C) di- or tricarboxylic acid are melt-kneaded at a resin temperature of 240 to 360 ° C. It is produced by adding (B) polyamide in two steps and melt-kneading at a resin temperature of 240 to 360 ° C., and adding (D) an antioxidant and / or (E) an impact modifier to the above-mentioned first step and / or A resin composition produced by adding in the second step.

The (A) PPE used in the present invention can be produced, for example, according to the method described in JP-A-63-286464. In particular, poly (2,6-dimethyl-1,
4-phenylene) ether, 2,6-dimethyl-1,4
-Phenol / 2,3,6-trimethyl-1,4-phenol copolymer and a graft copolymer obtained by graft-polymerizing styrene to the former two are used in the present invention.
Preferred as PE. The intrinsic viscosity of PPE suitable for the present invention was measured with a chloroform solution at 25 ° C. and was 0.30 to 0.6.
It is preferably in the range of 0 dl / g. Intrinsic viscosity is 0.
When it is higher than 60 dl / g, the melt viscosity of the composition becomes high,
The bar flow value decreases, making it especially difficult to mold large-sized thin-walled molded products. On the other hand, when the intrinsic viscosity is lower than 0.30 dl / g, the mechanical strength is largely deteriorated and the value as a practical molded product is impaired, so that it cannot be used in the PPE / polyamide resin composition of the present invention.

The (B) polyamide used in the present invention is
Aliphatic polyamides such as polyamide 4, polyamide 6, polyamide 66, polyamide 610, polyamide 11, polyamide 12; aromatic polyamides such as those obtained from polyhexadiamine terephthalamide, polyhexadiamine isophthalamide, metaxylene diamine and adipic acid. One or more polyamides selected from the above can be preferably used.

The di- or tricarboxylic acid (C) used in the present invention is a di- or tricarboxylic acid having 3 to 6 carbon atoms, preferably maleic acid, maleic anhydride, itaconic acid, fumaric acid, citric acid. , And at least one selected from malic acid.

The (D) antioxidant used in the present invention is
N, N'-hexamethylenebis (3,5-di-tertiarybutyl-4-hydroxy-hydrocinnamide,
2,4-Bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tertiarybutryanilino)-
1,3,5-triazine, pentaerythritol-tetrakis- [3- (3,5-di-tertiary-butyl-4]
-Hydroxyphenyl) -propionate], zinc oxide, and zinc sulfide. The physical properties of the resin composition of the present invention, particularly weld strength, thermal stability during molding, and deterioration resistance when used in a high temperature atmosphere, are uniquely exhibited only by using the above-mentioned antioxidant. To be done.

In the case of the present invention, when the content of the (B) polyamide is less than 30 parts by weight in the above-mentioned compounding ratio, fluidity,
It is poor in solvent resistance and oil resistance, and, unexpectedly, the elongation at break of the welded test piece is significantly reduced. If the polyamide content is higher than 70 parts by weight, the impact resistance and the deflection temperature under load decrease greatly, which is not preferable. On the other hand, when the polyamide addition rate is lower than 30 parts by weight, the breaking elongation of the welded test piece is greatly reduced, and thus it is excluded from the present invention.

In the above-mentioned blending ratio, the blending ratio of (C) di- or tricarboxylic acid is 0.1 to 5 parts by weight, whereby the average dispersed particle diameter of PPE is 3 μm or less, and stable strength is obtained. When the compounding ratio is less than 0.1 part by weight, the compatibilizing effect is small, the dispersed state of PPE and polyamide is not stable, and the mechanical properties such as delamination and impact resistance are largely deteriorated. Further, if the compounding ratio is more than 5 parts by weight, the mechanical strength and the deflection temperature under load are largely lowered, and the thermal stability at the time of molding and the deterioration of mechanical strength due to thermal deterioration when used in a high temperature atmosphere are severe. However, it may cause mold corrosion in some cases, which is not preferable.

Examples of the (E) impact resistance improver used in the present invention include polybutadiene, SBR, EPDM and EV.
A, polyacrylic acid ester, polyisoprene, hydrogenated isoprene, acrylic elastomer, diblock or triblock copolymer consisting of polystyrene phase and hydrogenated polyisoprene phase (for example, Kuraray Co., Ltd., trade name Septon), Polyester / polyether coelastomer, PA elastomer (for example, Toray Industries, Inc.)
Made, trade name Pebax), PA-based elastomer (for example, manufactured by Dainippon Ink and Chemicals, trade name Grelax A), ethylene / butene 1 copolymer, styrene / butadiene block copolymer, hydrogenated styrene / butadiene Block copolymers, ethylene / propylene copolymers, ethylene / propylene / ethylidene norbornene copolymers, thermoplastic polyester elastomers, hydrogenated SEBS elastomers (for example, Shell Chemical Co., Ltd., trade name Kraton G), ethylene -Α-olefin copolymer and propylene-α-olefin copolymer (for example, manufactured by Mitsui Petrochemical Co., Ltd., trade name Tuffmer), ethylene methacrylic acid-based special elastomer (for example, manufactured by Mitsui DuPont Polychemical Co., Ltd., trade name Tuffrit T3000) The core layer is rubber and the shell layer The core-shell type elastomer comprising a hard resin (e.g., Takeda Chemical Industries Co., Ltd.,
Trade name Stuffloid, acrylic (reaction type) elastomer (for example, Kuraha Chemical Co., Ltd., trade name Paraloid EXL), MBS elastomer and Kureha BT.
A elastomer, core / shell type elastomer (for example, Mitsubishi Rayon Co., Ltd., trade name Metabrene S), core / shell type elastomer in which the core is made of silicone rubber and the shell is made of acrylic rubber or acrylic resin (for example, Mitsubishi Rayon Co., Ltd. make, grade name S2001 or RK120) etc. are illustrated.

Further, other thermoplastic resins such as PS, HIPS, and M may be used within the range not impairing the object of the present invention.
S, MBS, AS, AAS, AES, AMBS, styrene-maleic acid copolymer resin (for example, manufactured by Arco Chemical Company of America, trade name Dailark), PC, PE, P
P, maleic acid-modified PP, POM, PMMA, various aliphatic polyamides and aromatic polyamides, polyphenylene sulfide, polyether ether ketone, polysulfone and the like can also be added.

The resin composition of the present invention has mechanical strength, rigidity,
To improve dimensional stability, glass fiber, glass beads, glass flakes, glass fiber cloth, glass fiber mat,
Graphite, carbon fiber, carbon fiber cloth, carbon fiber mat, carbon black, carbon flakes, aluminum, stainless steel, metal fibers and flakes made of brass and copper, metal powder, organic fibers, acicular needle titanate, mica, talc One or more reinforcing materials selected from clay, clay, (acicular) titanium oxide, wollastonite and calcium carbonate may be added. In order to increase the rigidity and strength and further improve the appearance and smoothness of the molded product, the diameter of the fiber may be reduced. As a glass fiber having a small fiber diameter, E-FMW-800 (average fiber diameter 0.8, manufactured by Nippon Mineral Co., Ltd.)
μm) and E-FMW-1700 (average fiber diameter 0.6μ)
m) can be illustrated.

The surface of the reinforcing material is a known surface treatment agent such as vinylalkylsilane, methacryloalkylsilane, epoxyalkylsilane, aminoalkylsilane,
The surface treatment may be performed with a titanate coupling agent such as mercaptoalkylsilane, chloroalkylsilane, isopropyltriisostearoyl titanate, or a zircoaluminate coupling agent. Further, as a sizing agent for the reinforcing material, a sizing agent such as a known epoxy type, urethane type, polyester type or styrene type sizing agent may be used for sizing.

The composition of the present invention may optionally contain, as a flame retardant, triphenyl phosphate, tricresyl phosphate, polycondensates thereof, or a known phosphorus compound such as red phosphorus. . Further, a halogen compound such as decabromodiphenyl ether, brominated polystyrene, low molecular weight brominated polycarbonate, or brominated epoxy compound can be added as a flame retardant. Flame retardant aids such as antimony trioxide, antimony tetraoxide, zirconium oxide can also be used in combination with the halogen compound.

If necessary, a phosphite stabilizer, an antistatic agent, a plasticizer, a lubricant, a release agent, a dye, a pigment, an ultraviolet absorber, a light stabilizer and the like are added to the composition of the present invention. can do.

In order to obtain a resin composition having remarkably excellent physical properties and moldability as in the present invention, it is necessary to devise a kneading method. That is, in the first step, di- or tricarboxylic acid and PPE, or di- or tricarboxylic acid and PPE
And impact modifier are melt-kneaded at a resin temperature of 240 to 350 ° C., preferably 260 to 330 ° C., and then polyamide is added in the second stage, and melted at a resin temperature of 240 to 350 ° C., preferably 260 to 330 ° C. Knead. The antioxidant is added in the first or second stage, but is preferably added in the second stage.

Contrary to the kneading method of the present invention, the kneading method in which the di- or tricarboxylic acid, the polyamide and the antioxidant are melt-kneaded in the first step and the remaining components are added in the second step is the object of the present invention. It is impossible to obtain a resin composition having remarkably excellent physical properties and moldability. Further, all the components constituting the present invention are mixed at the same time, and even in a composition obtained by melt-kneading, there is a problem that the Izod impact strength is significantly reduced as compared with the composition obtained by the kneading method of the present invention. Not preferable.

As is clear from the above description, the resin composition of the present invention can be used without impairing the appearance of molded products, mechanical properties, heat resistance, dimensional accuracy, fluidity during molding, solvent resistance and oil resistance. In particular, since it has significantly improved weld strength, thermal stability during molding, and heat deterioration resistance when used in a high temperature atmosphere, it is used in a wide range of fields such as electric / electronic parts, automobile parts, machine parts, construction parts, and sundries. it can.

[0022]

EXAMPLES The present invention will be specifically described with reference to the following examples and comparative examples, but the present invention is not limited to these. The molding method and test method of the test piece in the examples and comparative examples are as follows.

(1) Raw materials used Polyamide is Amylan CM1017 (PA manufactured by Toray Industries, Inc.)
(Abbreviated as 6), PPE used was manufactured by Mitsubishi Gas Chemical Co., Inc. and had an intrinsic viscosity in chloroform at 25 ° C. of 0.45 dl / g. As the di- or tricarboxylic acid, maleic anhydride (abbreviated as compound 1) and fumaric acid (abbreviated as compound 2) were used. As comparative examples, fumaric acid dibutyl ester (abbreviated as compound 3), maleic acid dimethyl ester (compound 4
Abbreviated), 1,4-hexadiene-3ol (compound 5
Abbreviated), propargyl alcohol (abbreviated as compound 6)
It was used. As the antioxidant, commercially available N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide (abbreviated as an inhibitor 1), pentaerythritol-tetrakis- [3- ( 3,5-di-tertiary-butyl-4-hydroxyphenyl) -propionate] (abbreviated as inhibitor 2) and zinc sulfide (abbreviated as inhibitor 3) were used. -Butyl-p-cresol (abbreviated as inhibitor 4)
3,5-Di-tertiary-butyl-4-hydroxy-benzophosphonate-di-ethyl ester (abbreviated as inhibitor 5), 2,2-thiobis- (4-methyl-6-tert-butylphenol) (inhibitor 6 Abbreviated) was used. As the impact modifier, a styrene / ethylene / butylene / styrene type block copolymer manufactured by Shell Chemical Co., Ltd. under the trade name of Kraton G1651 (abbreviated as SEBS) was used.

(2) Kneading Conditions of Composition Among the components constituting the resin composition of the present invention, first, PP
After mixing E, di- or tricarboxylic acid and SEBS in the ratios shown in Tables 1 to 3, at a cylinder set temperature of 290 ° C,
Pellets were produced by melt-kneading with a twin-screw extruder having a screw diameter of 30 mm. The remaining components shown in Tables 1 to 3 were mixed with the pellets, melt-kneaded with a twin screw extruder having a screw diameter of 30 mm at a cylinder setting temperature of 280 ° C. to produce pellets, which were used for molding test pieces in the next section. .

(3) Molding conditions for Izod impact test pieces After drying the pellets produced by the above method at 100 ° C. for 5 hours, the mold temperature was 100 ° C. and the cylinder was set by an SG125 injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. Temperature is 280 ° C., injection pressure is 98 MPa, 1 cycle is 50 seconds, 63.5 × 1
A 2.7 x 3.2 mm Izod impact test piece was molded for 20 shots using a mold that can mold 8 pieces in one shot, the first 15 shots were discarded, and the Izod test piece for the subsequent 5 shots was used. The impact strength was measured. In Tables 1 to 3, impact 1 is indicated.

(4) Thermal stability test during molding After the molding in (3), the molding was interrupted for 30 minutes at the cylinder set temperature of 280 ° C., and then the Izod impact test was conducted under the molding conditions of (3). Mold the piece for 2 shots, discard the test piece for the 1st shot, measure the Izod impact strength with the test piece for the 2nd shot, and determine the thermal stability during molding of the PPE / polyamide resin composition based on the magnitude of the Izod impact strength. Was evaluated. In Tables 1 to 3, impact 2 is indicated.

(5) Izod impact strength after heat treatment at 180 ° C for 100 hours After heat treatment of the Izod impact test piece molded in (3) in an oven at 180 ° C for 100 hours, the Izod impact strength was measured to obtain PPE / polyamide resin. The thermal stability of the composition in a high temperature atmosphere was evaluated. In Tables 1 and 2, it was designated as Impact 3.

(6) Izod impact strength measurement method According to ASTM-D256, a notch of 0.25R is cut into a test piece having a thickness of 3.2 mm by cutting,
After conditioning for 24 hours in an atmosphere of 23 ° C. and relative humidity of 50 ± 3%, measure 5 Izod impact strengths at 23 ° C.,
The average value (unit: J / m) of 5 lines is shown.

(7) Tensile test piece molding conditions and elongation at break measurement conditions Under the same conditions as the Izod impact test piece molding conditions of (3), ASTM D638 standard type 1 tensile test pieces of 3.2 mm thickness were used. A welded test piece having gates at both ends of the major axis of the tensile test piece was formed, and the tensile elongation at break was measured using the welded test piece, and the tensile elongation (unit:%) was displayed. The measurement conditions are 23 ° C. and a relative humidity of 50 ± 3% for 24 hours. After adjusting the condition for 24 hours, the atmosphere is 23 ° C. and the tensile speed is 10 m
Five pieces are measured at m / min, and an average value of the five pieces shows tensile elongation at break (unit:%).

Examples 1 to 8 Table 1 shows the compounding ratios of the constituents and the measurement results. In addition, the compounding ratio of each component which comprises the resin composition of Table 1 is shown by weight part.

Comparative Examples 1 to 9 Tables 2 and 3 show the compounding ratios of the constituents and the measurement results. In addition, the compounding ratio of each component which comprises the resin composition of Table 2 and Table 3 is shown by weight part. Comparative Examples 10 to 13 All components were mixed at the same time, and the cylinder temperature was 290.
Pellets were produced in the same manner as in Example except that the mixture was melt-kneaded by a twin-screw extruder having a screw diameter of 30 mm at 30 ° C. Using the pellets, molding of the test piece, Izod impact strength, and breaking elongation of the welded test piece were measured under the same conditions as in the examples. The results are shown in Table 4. Comparative Examples 14 to 17 PA, Compound 1 or 2, and Inhibitor 1 or 2
Was melted and kneaded with a twin-screw extruder having a screw diameter of 30 mm at a cylinder temperature of 290 ° C., and pellets were produced by the same operation as in the example. PP in this pellet
E and SEBS were added, and the mixture was melt-kneaded at a cylinder temperature of 290 ° C. with a twin-screw extruder having a screw diameter of 30 mm to produce pellets, and then test pieces were molded, and impact strength and elongation at break were measured. The results are shown in Table 4.

[0032]

The PPE / polyamide resin composition of the present invention is excellent in weld strength without impairing the appearance of molded products, mechanical properties, dimensional accuracy, fluidity during molding, solvent resistance and oil resistance, Since the thermal stability during molding and the heat deterioration resistance when used in a high temperature atmosphere are remarkably improved, it can be used in a wide range of fields such as electric / electronic parts, automobile parts, machine parts, construction parts and sundries.

[0033]

[Table 1]Example number 1 2 3 4 5 6 7 8 (Blending ratio) PPE 33 33 33 33 53 53 53 53 53 53 PA6 60 60 60 40 40 40 40 40 40 Compound 1 0.3 0.3 0.3 0.2 0.2 0.5 Compound 2 0.4 0.4 0.4 0.2 0.5 Inhibitor 1 0.3 0.6 0.3 Inhibitor 2 0.3 0.6 0.2 Inhibitor 3 0.3 0.6 0.3 0.3 0.2 SEBS 7 7 7 7 7 7 7 7 7 (Physical properties) Impact 1 280 290 270 320 320 330 320 330 310 Impact 2 250 250 250 240 300 310 290 310 310 280 Impact 3 230 220 220 220 280 280 270 280 260 Overstretched 45 31 48 35 41 37 37 24 37

[0034]

[Table 2] Comparative example number 1 2 3 4 5 6 (blending ratio) PPE 15 73 73 33 53 53 53 PA6 78 20 60 60 40 40 40 Compound 1 0.3 0.3 Compound 3 0.3 Compound 4 0.3 Compound 5 0.6 Compound 6 1.2 Inhibitor 1 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SEBS 7 7 7 7 7 7 7 (physical properties) Impact 1 60 130 40 40 50 55 60 Impact 2 50 90 40 40 40 50 50 Impact 3 40 80 40 50 45 45 45 Yes Elongation 22 3 4 2 3 4

[0035]

Table 3 Comparative Example No. 7 8 9 (Compounding ratio) PPE 33 33 33 33 PA6 60 60 60 Compound 1 0.3 0.3 0.3 0.3 Inhibitor 4 0.5 Inhibitor 5 0.5 Inhibitor 6 0. 5 SEBS 7 7 7 (Physical properties) Impact 1 140 130 130 150 Impact 2 70 50 60 Impact 3 65 40 50 Yes Elongation 5 5 4

[0036]

[Table 4]Comparative example number 10 11 12 13 14 15 15 16 17 (Compounding ratio) PPE 33 33 33 33 53 53 53 53 53 53 PA6 60 60 60 40 40 40 40 40 40 Compound 1 0.3 0.3 0.5 0.5 0.5 1.0 0.5 Compound 2 0.3 0.5 0.5 Inhibitor 1 0.3 0.3 0.3 0.3 0.3 Inhibitor 2 0.3 0.5 0.5 0.5 0.5 0.3 SEBS 7 7 7 7 7 7 7 7 7 (Physical Properties) Impact 1 70 65 50 50 60 55 50 50 50 50 Impact 2 55 50 45 45 55 45 40 40 45 45 Impact 3 50 40 50 50 40 40 40 40 40 Growth 2 3 3 2 2 3 4 3

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C08K 5/09 KKV C08L 77/00 LQV (72) Inventor Makoto Kobayashi 5-6-2 Higashihachiman, Hiratsuka-shi, Kanagawa Sanryo Gas Chemical Co., Ltd. Plastics Center

Claims (3)

[Claims] 1. A polyphenylene ether resin (A) (hereinafter abbreviated as PPE) 30 to 70 parts by weight, (B) polyamide 70 to 30 parts by weight, (C) di- or tricarboxylic acid having 3 to 6 carbon atoms 0.1. 5 parts by weight, (D) N, N'-hexamethylenebis (3,5-di-tert-butyl-4-
Hydroxy-hydrocinnamide), 2,4-bis-
(N-octylthio) -6- (4-hydroxy-3,5
-Di-tertiary butyrianilino) -1,3,5-triazine, pentaerythritol-tetrakis- [3-
0.01 to 3 parts by weight of one or more antioxidants selected from (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate], zinc oxide, zinc sulfide,
(E) A resin composition comprising 1 to 20 parts by weight of an impact modifier, wherein (A) PPE and (C) di- or tricarboxylic acid are melt-kneaded at a resin temperature of 240 to 360 ° C. It is produced by adding (B) polyamide in two steps and melt-kneading at a resin temperature of 240 to 360 ° C., and adding (D) an antioxidant and / or (E) an impact modifier to the above-mentioned first step and / or A resin composition produced by adding in the second step. 2. The resin composition according to claim 1, which is produced by adding the (E) impact modifier in the first step. 3. The (C) di- or tricarboxylic acid is at least one selected from maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, citric acid, and malic acid. The resin composition according to claim 1.