JP2001106907A - Polyamide resin composition improved in weather resistance and molded product using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both a polyamide resin composition excellent in moldability, thermal properties, mechanical characteristics and surface appearance, further excellent in gloss retaining properties even especially in environments of outdoor exposure with slight surface roughness and excellent in weather resistance and a molded product using the polyamide resin composition. SOLUTION: This polyamide resin composition is obtained by compounding 100 pts.wt. of a mixed polyamide resin comprising (A) 20-90 wt.% of polyamide 6 resin and/or polyamide 66 resin and (B) 10-80 wt.% of an aromatic polyamide resin with (C) 0-300 pts.wt. of an inorganic filler and (D) 0.05-5 pts.wt. of a hindered phenol. The aromatic polyamide resin is a polyamide resin prepared by a polycondensing reaction of a mixed diamine comprising 10-50 mol% of p-xylylenediamine and 50-90 mol% of m-xylylenediamine with an aliphatic dicarboxylic acid. Furthermore, the molded product is prepared by using the polyamide resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide resin composition and, more particularly, to an automotive or railway exterior or building material which has excellent gloss retention and has little surface roughness and color change even under an outdoor exposure environment. The present invention relates to a polyamide resin composition having improved weather resistance and a molded article using the same, which are optimal for parts such as housing.

[0002]

2. Description of the Related Art Polyamide resins are widely used in automobile parts, machine parts, building materials and housing-related parts because of their excellent mechanical properties, moldability and chemical resistance. However, polyamide resins are extremely susceptible to oxidative deterioration, and undesired phenomena such as a decrease in mechanical strength, generation of surface cracks and coloring are caused with a decrease in the degree of polymerization. In particular, this oxidative degradation is accelerated by heat and light, and its use is restricted in outdoor exposure. The addition of various stabilizers to a polyamide resin for the purpose of preventing these deterioration phenomena is disclosed in JP-A-48-93652 and JP-B-63-29823. However, these effects of improving weather resistance are not sufficiently satisfactory.
Further improvements are desired.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to provide excellent thermal physical properties, mechanical properties, and surface appearance.
It is another object of the present invention to provide a polyamide resin composition which has little surface roughness and color tone change and has excellent weather resistance, and a molded article using the same.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the present invention is as follows.
Polyamide 6 resin and / or polyamide 66 resin 20 to
90% by weight and (B) an aromatic polyamide resin 80 to 10
(C) 0 to 300 parts by weight of an inorganic filler and (D) 0.05 to 5 parts by weight of a phenolic antioxidant with respect to 100 parts by weight of a mixed polyamide resin comprising The polyamide resin is composed of 10 to 50 mol% of paraxylylenediamine and 50 to 9 of metaxylylenediamine.
A polyamide resin composition characterized by being a polyamide resin obtained from a mixed diamine containing 0 mol% and an aliphatic dicarboxylic acid, and a molded article using the same.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, it is necessary to use (A) a polyamide 6 resin and / or a polyamide 66 resin. Specifically, it is a polyamide 6 resin containing ε-caprolactam (hereinafter referred to as “CL”) or ε-aminocaproic acid as a main raw material and having 90 mol% or more of caprolactam unit, and the polyamide 6 resin is a comonomer other than caprolactam unit. -It may contain a unit composed of components. As a unit composed of a comonomer component other than the caprolactam unit,
For example, ω-laurolactam and the like can be mentioned. Furthermore, polyamide 6 containing an equimolar salt of hexamethylenediamine and adipic acid (hereinafter referred to as “AH salt”) as a main raw material.
6 resin, or 6/66 copolyamide having the AH salt and CL or ε-aminocaproic acid as main raw materials, or a blend of these polyamide resins. In the present invention, it is particularly preferable to use a polyamide 6 resin. (A) polyamide 6 resin and / or
Alternatively, the relative viscosity of the polyamide 66 resin is preferably 1.8 to 3.5, more preferably 2, under the measurement conditions at a concentration of 1 g / 100 ml in 98% sulfuric acid and a temperature of 25 ° C.
0 to 3.2, most preferably 2.1 to 3.0. You. If the relative viscosity is too low, the mechanical strength is insufficient, and if it is too high, the moldability decreases. The aromatic polyamide resin (B) in the present invention is obtained by a polycondensation reaction between a mixed diamine containing 10 to 50 mol% of paraxylylenediamine and 50 to 90 mol% of metaxylylenediamine and an aliphatic dicarboxylic acid. Polyamide resin.

In the mixed diamine, when the amount of paraxylylenediamine is less than 10 mol%, the crystallization rate of the aromatic polyamide resin obtained is low, and the deformation and the mechanical strength of the molded article are deteriorated due to the deterioration of the moldability or insufficient crystallization of the molded article. If the content exceeds 50 mol%, the melting point of the obtained aromatic polyamide resin becomes too high, which tends to cause thermal deterioration due to heating during molding, making molding difficult. As the mixed diamine, more preferably, 20 to 45 mol% of paraxylylenediamine and 55 to 55% of metaxylylenediamine are used.
It is a mixed diamine consisting of 80 mol%, most preferably a mixed diamine consisting of 20 to 40 mol% of para-xylylenediamine and 60 to 80 mol% of meta-xylylenediamine. Examples of the diamine in the mixed diamine include an aliphatic diamine, an aromatic diamine, and an alicyclic diamine in addition to para-xylylenediamine and meta-xylylenediamine. The proportion of diamines other than para-xylylenediamine and meta-xylylenediamine is preferably 10 mol% or less of all diamines, more preferably 5 mol% or less of all diamines. Examples of the aliphatic diamine include tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, octamethylene diamine, and nonamethylene diamine, and examples of the aromatic diamine include metaphenylenediamine and paraphenylenediamine. And alicyclic diamines such as 1,3-bisaminomethylcyclohexane,
4-bisaminomethylcyclohexane and the like.

As the aliphatic dicarboxylic acid, preferably, an α, ω-linear aliphatic dicarboxylic acid is used. The aliphatic dicarboxylic acid preferably has 6 to 12 carbon atoms.
Specific examples of the aliphatic dicarboxylic acid include adipic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid and the like. In the aromatic polyamide resin, a small amount of aromatic dicarboxylic acid can be used in addition to the aliphatic dicarboxylic acid. As the aromatic dicarboxylic acid, 1,
5-naphthalenedicarboxylic acid and the like. The proportion of aromatic dicarboxylic acid is preferably 1% of all dicarboxylic acids.
0 mol% or less, more preferably 5 mol% or less. (B) The relative viscosity of the aromatic polyamide resin is 96%
Measurement at a concentration of 1 g / 100 ml in sulfuric acid and a temperature of 25 ° C.
Preferably it is 1.6 to 3.0, more preferably 1.
7 to 2.9, and most preferably 1.8 to 2.8. If the relative viscosity is too low, the mechanical strength is insufficient,
If it is too high, the moldability will decrease. The mixed polyamide resin in the present invention comprises (A) a polyamide 6 resin and / or a polyamide 66 resin and (B) an aromatic polyamide resin, and (A) a polyamide 6 and / or a polyamide 66 resin and (B) an aromatic polyamide resin. The ratio with the polyamide resin is 20
To 90% by weight / 10 to 80% by weight, preferably 2% by weight.
5 to 85% by weight / 75 to 15% by weight, preferably 25 to 75% by weight / 75 to 25% by weight (but a total of 100% by weight) in the dish. Polyamide 6 resin and / or
Or when the polyamide 66 resin is less than 20% by weight,
The discoloration of the obtained polyamide resin composition after the exposure test is increased, and if it exceeds 90% by weight, the elastic modulus and the strength are undesirably small.

Further, (A) a polyamide 6 resin and / or a polyamide 66 resin and (B) an aromatic polyamide resin having different viscosities at the time of melting are used.
By utilizing the difference, characteristics can be given to the physical properties of the obtained polyamide resin composition. This polyamide 6
The viscosity of the resin and / or polyamide 66 resin at the time of melting can be usually measured using a capillary viscometer.
At this time, for example, the surface of a molded product molded using a polyamide resin composition having a melt viscosity of (A) a polyamide 6 resin and / or a polyamide 66 resin <(B) an aromatic polyamide resin, has (A) a polyamide 6 resin And / or the polyamide 66 resin is more likely to be present, and the molded article obtained is excellent in physical properties, particularly excellent in impact resistance and resistance to discoloration under outdoor exposure, while having a melt viscosity of (A) polyamide 6 resin and / or Alternatively, a molded article molded using a polyamide resin which is a polyamide 66 resin> (B) an aromatic polyamide resin has characteristics such as excellent elasticity retention at high temperatures and excellent surface fastness under outdoor exposure. In order to impart such characteristics to the polyamide resin composition, the ratio of the larger melt viscosity to the smaller melt viscosity under the same temperature and the same shear rate is preferably 1.5 or more, More preferably, (A) polyamide 6 is 2.0 or more.
Resin and / or polyamide 66 resin and (B) aromatic polyamide resin are used in combination. Further, as the inorganic filler (C), a known inorganic filler can be used, and the shape is not particularly limited, and any shape such as a fiber shape, a plate shape, a needle shape, a spherical shape, and a powder can be used. Good. Examples of the inorganic filler include glass fiber, carbon fiber, talc, mica, glass flake, wollastonite, potassium titanate whisker, magnesium sulfate, sepiolite, zonolite, aluminum borate whisker, and glass bead.
, Balloon, calcium carbonate, silica, kaolin, clay, titanium oxide, barium sulfate, zinc oxide, magnesium hydroxide and the like, and these can be used alone or as a mixture of two or more. Preferably, the inorganic filler is glass fiber, talc, or mica.

The amount of the inorganic filler (C) is from 0 to 300 parts by weight based on 100 parts by weight of the mixed polyamide resin. If the amount of the inorganic filler (C) exceeds 300 parts by weight, the moldability will be reduced and the appearance of the product will be poor. The amount of the inorganic filler is preferably 45 parts by weight or more and 300 parts by weight or less, more preferably 45 parts by weight or more and 200 parts by weight or less, from the viewpoint of strength such as impact resistance and elastic modulus. Preferably it is 45 to 180 parts by weight, most preferably 50 to 150 parts by weight. In the present invention, particularly when a large amount of an inorganic filler is blended in this way, it is possible to achieve both the above-mentioned strength points, as well as the appearance improvement and maintenance points such as low surface gloss retention and low surface roughness, Most features of the present invention appear.
In the present invention, weather resistance can be improved by blending (D) a phenolic antioxidant in addition to the above components. (D) used in the present invention
The phenolic antioxidant is a so-called hindered phenol, for example, 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-
Methylphenyl) propionyloxy] -1,1-dimethylethyl {-2,4,8,10-tetraoxaspiro [5,5] undecane, pentaerythrityl-tetrakis [3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 3,5-di-t-butyl-4 -Hydroxy-benzylphosphonate-diethyl ester and the like. (D) The phenolic antioxidant is added in an amount of 100 parts by weight of the mixed polyamide resin.
It is 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight, more preferably 0.2 to 2 parts by weight. 0.0
If it is less than 5, the effect on the improvement of weather resistance is small, and if it is more than 5 parts by weight, the decrease in mechanical properties is undesirably large. Further, the vapor pressure of the phenolic antioxidant at 25 ° C. is preferably 10 ⁻⁶ Pa or less. If the vapor pressure is higher than 10 ^-6 , it is easy to volatilize during processing, the workability may be reduced, or when formed into a molded product, these concentrations may be reduced, and the weather resistance may be reduced, which is not preferable.

In the polyamide resin composition of the present invention, in addition to the above-mentioned components, various additives, dyes and pigments, mold release agents, lubricants, nucleating agents, and the like generally used in polymer materials are appropriately compounded. Can be. As a method for producing the polyamide resin composition of the present invention, a usual method can be adopted, and there is no particular limitation. For example, a method of melt-kneading a polyamide resin, possibly an inorganic filler, and a phenolic antioxidant in an arbitrary order by using a conventional device, for example, a vented extruder or a device similar thereto is used.
The polyamide resin composition obtained by the melt-kneading can be formed into a molded product by a known method, and can be used for various applications. It has excellent performance when used for Specific examples of the use include exterior parts for automobiles such as fenders, bumpers, wheel caps, aero parts, door mirror stays, roof rails, exterior parts for railways, parts for windows, etc., and parts for building materials and housing, etc. However, the present invention is not limited to these.

[0011]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. The raw materials used in the examples and comparative examples are as follows. (1) Nylon 6 resin: a product of Mitsubishi Engineering-Plastics Corporation, trade name: Novamid (registered trademark) 1
007J, relative viscosity 2.2 (2) Aromatic nylon resin: Aromatic polyamide resin obtained in the following reference example (3) Nylon MXD6: a product of Mitsubishi Gas Chemical Co., Ltd., from meta-xylylenediamine and adipic acid The obtained polyamide, relative viscosity 2.14 (measured at a temperature of 25 ° C. using 98% sulfuric acid as a solvent) (4) Inorganic filler: Talc, a product of Hayashi Kasei Co., Ltd., trade name: Micron White 5000A, average particle size 4.1 μm talc A, product of Fuji Talc Co., Ltd., trade name: TM-2,
Average: 5.0 to 6.0 μm (5) Glass fiber: 3 mm long chopped strand, product of Asahi Fiberglass Co., Ltd., trade name: CS03
-JAFT2 (6) Phenolic antioxidant: 3,9-bis @ 2-
[3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, Asahi Denka Kogyo Co., Ltd. products and products
Name: Adegastab AO-80. Vapor pressure 1.0 × 10 ^-12
pa (7) Hindered amine: a product of Asahi Denka Kogyo Co., Ltd., trade name: Adegastab LA-52 (8) Benzotriazole: 2- [2-hydroxy-
3,5-bis (α, α-dimethylbenzyl) phenyl]
-2H-benzotriazole, Nippon Ciba Geigy Co., Ltd.
Product, trade name: Tinuvin 234, vapor pressure: 2.0 × 10
^-10 Pa (9) Copper iodide, a product of Nippon Chemical Industry Co., Ltd. (10) Potassium iodide, a product of Nippon Chemical Industry Co., Ltd.

Reference Example Adipic acid was heated and melted in a reaction vessel in a nitrogen atmosphere. A mixed xylylenediamine containing 30 mol% of paraxylylenediamine and 70 mol% of metaxylylenediamine was added dropwise to the molten dicarboxylic acid, followed by stirring while maintaining the reaction temperature so as to always exceed the melting point of the product. . After completion of the dropwise addition, the mixture is stirred and reacted until the viscosity reaches a predetermined value.
It was cooled with water and pelletized. The obtained aromatic polyamide has a melting point of 258 ° C., a crystallization temperature of 206 ° C., and a relative viscosity (96 ° C.).
% Sulfuric acid solution 1 g / 100 ml) was 2.08.

In the following Examples and Comparative Examples, evaluation of moldability, accelerated deterioration test, and surface observation test were performed as follows. (1) Evaluation of moldability A box-shaped product having a size of 100 × 150 × 50 mm and a thickness of 2 mm was subjected to a resin temperature of 275 ° C., a mold temperature of 90 ° C., and an injection pressure of 50 °.
0 kgf / cm ² , injection speed 50 mm / sec, holding pressure 3
00kgf / cm ² , Injection holding time 12 seconds, Cooling time 2
Molding was performed in 0 seconds, and the releasability at the time of molding and the appearance of the molded product were evaluated on the following three levels. ：: Good releasability, with almost no surface roughness. Δ: The releasability was somewhat poor, and surface roughness was observed. X: The releasability is poor and the surface roughness is remarkable. (2) Accelerated Deterioration Test A 70 mm × 70 mm, 3 mm-thick mirror-surface square plate was subjected to a resin temperature of 275 ° C., a mold temperature of 90 ° C., and an injection pressure of 500 kgf /
cm ² , injection speed 30mm / sec, holding pressure 200kgf
/ Cm ² , injection holding pressure time 12 seconds, cooling time 20 seconds, and the following various accelerated deterioration tests were performed. The weather resistance was evaluated based on the change in gloss and color difference before and after the test. The test conditions, gloss, and color difference were measured by the following methods. 1) Super UV test A continuous light irradiation test using iSuper UV (trade name) was performed. Weather resistance was evaluated based on changes in gloss before and after the test. Each test condition and measurement of glossiness (gloss) and color difference were performed by the following methods. Test conditions Test piece: mirror-surface square plate (mirror-sharpened # 3000-finished die-shaped square plate) Light intensity: 50 mW / cm ² (295-450 nm) Humidity: 90% or more relative humidity Temperature: 63 ± 3 ° C. Test time: 200 hours 2) Sunshine fade test Test conditions Test piece: Mirror-faced square plate (square plate molded with a mirror-polished # 3000 finish mold) Light intensity: 75 W / m ² Temperature: 83 ± 3 ° C Test time : 400 hours [Measurement of glossiness (gloss)] The measurement of glossiness is based on JIS Z
Performed according to the method of 8741. As a measuring instrument, UGV-5K (trade name) manufactured by Suga Test Instruments Co., Ltd. was used. The measurement angle was 60 degrees. The larger the measured value, the closer to the mirror state. [Measurement of color difference] The color difference was measured by a reflection method according to the method of JIS Z8722. The measuring device is a multi-light source spectrophotometer manufactured by Suga Test Instruments Co., Ltd., MSC-5N-GV5.
(Product name) was used. The optical system is d / 8 condition, the luminous flux is φ
The measurement was performed at 15 mm. The smaller the measured value, the smaller the color difference. (3) Surface Observation Test The square plate after accelerated deterioration obtained by the method of (2) was observed with a stereoscopic microscope, and the surface condition was evaluated in the following four stages. A: Surface roughness is hardly observed. ：: Surface roughness is slightly observed. Δ: Surface roughness is observed. X: Surface roughness is remarkably observed.

Examples 1 and 2 and Comparative Examples 1 to 4 The components shown in Table 1 were weighed in the amounts shown in the table, and tumbled.
After melt-kneading at 270 ° C. with a vented extruder, the mixture was extruded into a string, cooled in a water bath, cut and dried to form pellets. Table 1 shows the evaluation results of the obtained materials. The accelerated deterioration test was performed by a super UV test.

[0015]

[Table 1]

Example 3 and Comparative Example 5 The components shown in Table 2 were weighed in the amounts shown in the table, mixed by a tumbler, melted and kneaded at 270 ° C. by a vent type extruder, and extruded into a string. After cooling in a water bath, cutting and drying were performed to obtain pellets. The evaluation results of the obtained materials are shown in the same table. In addition, the accelerated deterioration test was performed by a sunshine fade test using a mirror surface square plate as a test piece.

[0017]

[Table 2]

[0018]

Industrial Applicability The polyamide resin composition of the present invention, in addition to the inherent properties inherent in polyamide, has excellent gloss retention even under an outdoor exposure environment, and has little surface roughness and little change in color tone. It can be used for exterior parts for automobiles and railways, building materials and housing parts that require weather resistance, and is extremely useful. Further, the polyamide resin composition of the present invention has excellent moldability and is advantageous for producing various molded products.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/13 C08K 5/13 7/14 7/14 C08L 77/00 C08L 77/00 (72) Inventor Masaki Hirono 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Inside the Engineering Center of Mitsubishi Engineering-Plastics Co., Ltd. (72) Inventor Kazuo Yamamiya 5-6-1-2 Higashi-Yawata, Hiratsuka-shi, Kanagawa Mitsubishi Engineering-Plastics Co., Ltd. Inside the technical center

Claims (11)

[Claims] (1) 100 parts by weight of a mixed polyamide resin comprising (A) 20 to 90% by weight of a polyamide 6 resin and / or a polyamide 66 resin and (B) 10 to 80% by weight of an aromatic polyamide resin, ) Inorganic filler 0-300
Parts by weight, and 0.05 to 5 parts by weight of (D) a phenolic antioxidant, wherein the aromatic polyamide resin contains 10 to 50 mol% of paraxylylenediamine and 50 to 90 mol% of metaxylylenediamine. A polyamide resin composition obtained by a polycondensation reaction of a mixed diamine containing the following and an aliphatic dicarboxylic acid. 2. The polyamide resin composition according to claim 1, wherein the relative viscosity of (A) the polyamide 6 resin and / or the polyamide 66 resin is 1.8 to 3.5. 3. A mixed diamine comprising 20 to 45 mol% of paraxylylenediamine and 55 to 8% of metaxylylenediamine.
The polyamide resin composition according to claim 1 or 2, which is a mixed diamine containing 0 mol%. 4. The polyamide resin composition according to claim 1, wherein the aliphatic dicarboxylic acid is an α, ω-linear aliphatic dicarboxylic acid. 5. An aliphatic dicarboxylic acid having 6 to 12 carbon atoms.
2. An aliphatic dicarboxylic acid according to claim 1,
5. The polyamide resin composition according to any one of items 1 to 4. 6. The polyamide resin composition according to claim 1, wherein the relative viscosity of the aromatic polyamide resin (B) is from 1.6 to 3.0. 7. The polyamide resin composition according to claim 1, wherein (C) the inorganic filler is an inorganic filler selected from the group consisting of glass fiber, talc and mica. . 8. The polyamide resin composition according to claim 1, wherein the total amount of the component (A) is a polyamide 6 resin. 9. A molded article obtained by molding the polyamide resin composition according to claim 1 for outdoor use. 10. The method according to claim 9, wherein (A) the melt viscosity of the polyamide 6 resin and / or the polyamide 66 resin <
(B) A molded article obtained by molding a polyamide resin composition having a melt viscosity of an aromatic polyamide resin. 11. The method according to claim 9, wherein (A) a melt viscosity of the polyamide 6 resin and / or the polyamide 66 resin.
(B) A molded product obtained by molding a polyamide resin composition having a melt viscosity of an aromatic polyamide resin.