JP2000178441A - Polyamide resin composition, and formed product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition, excellent in mechanical characteristics (in particular resistance to impact) and resistance to weather, and giving a formed product of high surface smoothness. SOLUTION: This polyamide resin composition contains 30 to 70 wt.% of a polyamide resin having a crystallization temperature of 210 deg.C lower, and 70 to 30 wt.% of glass fibers having an average aspect ratio of 10 to 20 and average fiber diameter of 15 to 30 μm. It is preferable that glass fibers having an aspect ratio of 5 or less account for 15 wt.% or less of the total glass fibers.

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 having excellent surface smoothness, mechanical properties, and weather resistance, and a molded article formed therefrom.

[0002]

2. Description of the Related Art Polyamide resins have been used in various applications because they have excellent mechanical properties and, particularly when reinforced with glass fibers, have a remarkable effect of improving strength and rigidity.
However, when glass fibers are blended with a relatively high content in order to improve strength and rigidity, for example, a molded product obtained by injection molding has glass fiber exposed on its surface and the appearance of the molded product , There is a problem that its use is limited.

[0003] As a method for solving these problems, for example, polyamide (hereinafter referred to as nylon MXD6) obtained by polymerizing adipic acid and meta-xylylenediamine having relatively low crystallization temperature among polyamide resins, adipic acid,
A composition in which a polyamide obtained by copolymerizing isophthalic acid and hexamethylenediamine (hereinafter, referred to as a nylon 66 / 6I copolymer) or the like and which is reinforced with a glass fiber has been proposed.

Further, as another method for improving the appearance of a molded article, for example, Japanese Patent Application Laid-Open Nos. Sho 56-30460 and
JP-A-3-156856 discloses a resin composition in which a glass fiber is blended with a polyester resin or a nylon 46 resin to improve the balance between appearance and mechanical properties by defining the glass fiber length. I have. However, the glass fiber reinforced resin composition as described above can prevent the glass fiber from being exposed to some extent, and can obtain a molded article having an excellent appearance. It was not sufficient for applications requiring molded articles without irregularities (hereinafter referred to as undulations) having a period of about 1 to 5 mm, and was not sufficiently satisfactory such as poor mechanical properties. In particular, nylon 46 has a problem that the crystallization temperature is as high as 250 ° C., and it is difficult to obtain a molded article with good appearance, and molding is difficult because the molding condition range for obtaining a molded article with good appearance is narrow. there were.

In order to solve the above-mentioned problems, the present inventors focused on glass fibers in a glass fiber reinforced polyamide resin, and defined the average aspect ratio and the content of glass fibers having a large aspect ratio to thereby improve the surface area. A polyamide resin composition having an excellent balance between smoothness and mechanical properties has been found, and the invention described in JP-A-10-120900 has been filed first.

However, the polyamide resin composition has a higher level of mechanical properties, especially a higher level of impact strength, appearance (gloss and surface smoothness) and weatherability (particularly, in the environment in which it is used, ultraviolet light). However, it is not sufficiently satisfactory in applications in which it is required to be resistant to the phenomenon of deterioration due to rain (water), glass fibers being exposed on the surface, and whitening due to loss of gloss.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional polyamide resin composition, that is, it is excellent in mechanical properties (particularly impact resistance) and weather resistance, and has an excellent surface property. An object of the present invention is to provide a polyamide resin composition from which a molded article excellent in gloss and surface smoothness can be obtained, and a molded article thereof.

[0008]

Means for Solving the Problems In order to achieve the above object, the present inventors have studied the polyamide resin composition and the components constituting the same in more detail, and as a result, have a better appearance of the molded product. It has been found that there is a polyamide resin molded product excellent in impact strength and weather resistance.

[0009] In particular, the present inventors have surprisingly found that the use of glass fibers having an unprecedently large diameter significantly improves the shock resistance (notched Izod characteristic) and the weather resistance. Have found the present invention. That is, the present invention is as follows. 1) Polyamide resin 3 having a crystallization temperature of 210 ° C. or lower
A polyamide resin composition comprising 0 to 70% by weight and 70 to 30% by weight of glass fiber, wherein the glass fiber has an average fiber diameter of 15 to 30 µm and an average aspect ratio of 10 to 20. . 2) The polyamide resin composition as described in 1 above, wherein the content of glass fibers having an aspect ratio of 5 or less is 15% by weight or less of the total glass fiber content. 3) A polyamide resin comprising: (a) 70 to 95% by weight of a hexamethylene adipamide component obtained from adipic acid and hexamethylenediamine; and (b) 30 to 95% by weight of a hexamethylene isophthalamide component obtained from isophthalic acid and hexamethylenediamine. 3. The polyamide resin composition as described in 1 or 2 above, which is a copolymer comprising 5% by weight. 4) 30-70% by weight of polyamide resin and glass fiber 70
A polyamide having an average aspect ratio of the glass fiber of 9 to 18, an average fiber diameter of 15 to 30 μm, and a crystallization temperature of the polyamide resin of 210 ° C. or less. Resin molded products. (5) The polyamide resin molded product as described in (4) above, wherein the content of glass fibers having an aspect ratio of 5 or less is 15% by weight or less of the total glass fiber content. 6) The polyamide resin is (a) 70 to 95% by weight of a hexamethylene adipamide component obtained from adipic acid and hexamethylene diamine, and (b) a hexamethylene isophthalamide component obtained from (b) an isophthalic acid and hexamethylene diamine. 6. The polyamide resin molded product according to the above item 4 or 5, wherein the molded product is a copolymer composed of at least 1% by weight. 7) The polyamide resin molded product according to the above 4, 5 or 6, wherein the polyamide resin molded product is an injection molded product.

Hereinafter, the present invention will be described in detail. The polyamide resin composition according to the present invention comprises a polyamide resin and glass fibers. In the present invention, it is necessary to use a polyamide resin having a crystallization temperature of 210 ° C. or lower. The crystallization temperature of the polyamide resin in the present invention is determined by a differential thermal analyzer (DSC).
And the peak top temperature of the crystallization peak in the differential thermal analysis chart measured at a temperature lowering rate of 20 ° C./min after holding the sample at a temperature of melting point + 20 ° C. for 5 minutes.

In the present invention, polyamide resins having a crystallization temperature of 210 ° C. or lower include, for example, ε-caprolactam, adipic acid, sebacic acid, dodecane diacid, isophthalic acid, terephthalic acid, hexamethylene diamine, tetramethylene diamine. 2-, methylpentamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine,
A homopolymer alone, a copolymer alone, a mixture of homopolymers, a mixture of copolymers, and a copolymer obtained by appropriately combining nylon-forming monomers such as meta-xylylenediamine and bis (3-methyl-4-aminocyclohexyl) methane. A mixture of the union and the homopolymer can be used. As a specific example of such a polyamide resin,
For example, nylon 6, nylon 610, nylon 61
2, nylon 11, nylon 12, nylon MXD6,
Nylon (nylon 6I) obtained by polymerizing hexamethylenediamine and isophthalic acid, isophthalic acid and bis (3-
Homopolymers such as nylon (nylon PACMI) obtained by polymerizing methyl-4aminocyclohexyl) methane, nylon (nylon 66 / 6I copolymer) obtained by polymerizing adipic acid, isophthalic acid and hexamethylenediamine, isophthalic acid (Nylon 6I / 6T copolymer) obtained by polymerizing terephthalic acid and hexamethylenediamine, and terephthalic acid, 2,2,4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine Nylon (Nylon TM
DT copolymer), copolymerized nylon obtained by polymerizing isophthalic acid, terephthalic acid, hexamethylenediamine and bis (3-methyl-4-aminocyclohexyl) methane, and isophthalic acid, terephthalic acid, hexamethylenediamine and bis (3-methyl-4 Examples thereof include a mixture of nylon 6 and a copolymerized nylon obtained by polymerizing aminocyclohexyl) methane, and a blend of nylon 66 and MXD6, but the present invention is not limited thereto.

When the crystallization temperature of the polyamide resin and / or the molded product of the polyamide resin exceeds 210 ° C., the surface of the obtained molded product is exposed to glass fibers so much that a molded product having an excellent appearance cannot be obtained. Particularly preferred polyamide resins in the present invention include (a) 70 to 95% by weight of a hexamethylene adipamide component (hereinafter referred to as 66 components) obtained from adipic acid and hexamethylene diamine and (b) an isophthalic acid and hexamethylene diamine. Hexamethylene isophthalamide component (hereinafter referred to as 6I
Component) 30 to 5% by weight of a copolymer. A molded article obtained by using this polyamide resin has less decrease in mechanical properties when absorbing water, and has an appearance (glossiness) and mechanical properties (strength). , Rigidity, impact resistance) and weather resistance are particularly excellent.

When the content of the 6I component is less than 5% by weight, the glass fiber is extremely exposed to the surface of the molded product, and a sufficiently good appearance is not always obtained, especially when a high content of glass fiber is blended. Further, the mechanical properties at the time of water absorption may be inferior. When the 6I component is more than 30% by weight,
It is substantially amorphous and mechanical properties during heating are not always sufficient, and there is a limitation on molding that a good appearance may not be obtained unless the mold temperature is raised to 100 ° C. or higher.

In the present invention, the molecular weight of the polyamide resin used is not particularly limited, but the relative viscosity of sulfuric acid (ηr: 1 g of polymer / 95.5% sulfuric acid 100 ml, measured at 25 ° C.)
Is preferably from 1.5 to 3.5, and more preferably from 2.0 to 3.
Those having a range of 0 can be particularly preferably used. The glass fiber that can be used in the present invention is not particularly limited as long as it is a glass fiber usually used as a reinforcing material. For example, 0.2-6
Any of chopped strands previously cut to a length of mm, milled fibers or cut fibers that have been ground or cut into a predetermined fiber length distribution can be used. If necessary, glass fibers surface-treated with a sizing agent or a coupling agent may be used.

The polyamide resin composition of the present invention has an average aspect ratio of glass fibers contained therein of 10 to 20.
And the average fiber diameter must be in the range of 15 to 30 μm. In addition, the content of glass fibers having an aspect ratio of 5 or less is particularly preferably 15% by weight or less of the total glass fiber content. A more preferable average aspect ratio is 12 to 19, and a more preferable average fiber diameter is 20 to 25 μm. If the average aspect ratio is less than 10, the mechanical properties expected according to the amount of the glass fiber cannot be sufficiently exhibited. If the average aspect ratio exceeds 20, undulation may be significantly generated on the surface of the molded product. When the average fiber diameter is less than 15 μm, the average aspect ratio is 10 to 2
Even if it is controlled to 0, it is difficult to achieve a sufficiently satisfactory level of impact resistance and weather resistance. Average fiber diameter is 30μ
If it exceeds m, the mechanical properties expected according to the amount of the glass fiber cannot be sufficiently exhibited. Further, glass fibers having an average fiber diameter of more than 30 μm are not preferable because they have problems in productivity and handling properties. If the content of glass fibers having an aspect ratio of 5 or less is more than 15% by weight, impact resistance (notched Izod characteristics) may not be sufficient.

In the polyamide resin molded article of the present invention, the average aspect ratio of the glass fibers contained therein must be in the range of 9 to 18, and the average fiber diameter must be in the range of 15 to 30 μm. In addition, the content of glass fibers having an aspect ratio of 5 or less is 1% of the total glass fiber content.
It is particularly preferred that the content be 5% by weight or less. A more preferable average aspect ratio is 11 to 16, and a more preferable average fiber diameter is 20 to 25 μm. If the average aspect ratio is less than 9, the mechanical properties expected according to the blending amount of the glass fiber cannot be sufficiently exhibited. On the other hand, if the average aspect ratio exceeds 18, undulations may be remarkably generated on the surface of the molded product. Average fiber diameter is 1
When it is less than 5 μm, even if the average aspect ratio is controlled to 10 to 20, it is difficult to obtain a sufficiently satisfactory level of impact resistance and weather resistance. If the average fiber diameter exceeds 30 μm, the mechanical properties expected according to the amount of the glass fiber cannot be sufficiently exhibited. Further, glass fibers having an average fiber diameter of more than 30 μm are not preferable because they have problems in productivity and handling properties. If the content of glass fibers having an aspect ratio of 5 or less is more than 15% by weight, impact resistance (notched Izod characteristics) may not be sufficient.

First, as described above, the inventors of the present invention determined the average aspect ratio of the glass fibers in the glass fiber reinforced polyamide resin and the content of the glass fibers having a large aspect ratio to thereby improve the surface smoothness. , And a polyamide resin composition having an excellent balance of mechanical properties,
Although the invention described in Japanese Patent Application Laid-Open No. 10-120900 has been reached, the present invention is a further remarkable improvement of the invention described in the Japanese Patent Application Laid-Open No. H10-120900. This makes it possible to provide a polyamide resin composition having an excellent balance between appearance (glossiness, surface smoothness) and weather resistance.

In the present invention, the average fiber diameter and average aspect ratio of the glass fibers of the polyamide resin composition, and the content of the glass fibers having an aspect ratio of 5 or less are such that the glass fibers in the polyamide resin composition pellets are 300 to 100.
0 is randomly extracted and measured by actual measurement under an optical microscope. The number average fiber diameter is defined as the average glass fiber diameter. The value obtained by dividing the weight average fiber length by the number average fiber diameter is defined as the average aspect ratio. 300 to 10
Based on the distribution data of the fiber diameter and fiber length of 00 glass fibers, the aspect ratio with respect to the total glass fiber amount was 5
The following glass fiber content is determined. In the case of a polyamide resin molded product, the molded product is of a size that does not substantially affect the glass fiber length (for example, about 3 mm square).
And the average fiber diameter, the average aspect ratio, and the content of glass fibers having an aspect ratio of 5 or less are determined in the same manner as in the case of the polyamide resin composition.

The compounding ratio of the polyamide resin of the present invention and the glass fiber is 30 to 70% by weight of the polyamide resin and 70 to 30% by weight of the glass fiber. If the amount of the polyamide resin is less than 30% by weight, the glass fibers are exposed on the surface of the molded product, and the appearance is significantly impaired. If the amount of the polyamide resin is more than 70% by weight, the mechanical properties do not reach a satisfactory level. In the region where the amount of such glass fibers is small,
In particular, even if the aspect ratio of the glass fiber is not specified, a molded article having a relatively good appearance with little undulation can be obtained.

The polyamide resin composition according to the present invention comprises:
Although the production method is not particularly limited, pellets can be obtained by melting and kneading the polyamide resin and the glass fibers using a commonly used single-screw or twin-screw extruder. In order to control the average aspect ratio of the glass fiber to the range described in the present invention, for example, using a glass fiber having an appropriate aspect ratio, the temperature of the melt-kneading, the discharge rate, the screw design and the number of revolutions, the raw material supply position are appropriately set By selecting, you can control.

The polyamide resin composition according to the present invention is usually obtained in the form of pellets, and the pellets may be formed into molded articles by various molding methods such as compression molding, injection molding and extrusion molding. The effect of using the polyamide resin composition of the present invention appears particularly in injection molded articles. The injection molded product in the present invention includes a molded product obtained by a special injection molding such as gas assist molding and two-color molding in addition to ordinary injection molding within a range not to impair the object of the present invention.

The injection molding conditions in this case include, for example, a molding temperature in the range of 250 to 310 ° C. and a mold temperature of 4
What is necessary is just to let it be the range of 0-120 degreeC. The polyamide resin composition of the present invention contains 1 as long as the object of the present invention is not impaired.
One or more conventional additives may be added, such as stabilizers and inhibitors against oxidation, heat, and UV degradation, lubricants and release agents, coloring agents including dyes and pigments, nucleating agents, A foaming agent, a plasticizer, an inorganic filler, a flame retardant, an antistatic agent and the like can be appropriately added.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples and comparative examples. In addition, the resin composition, the evaluation method of a molded article, the used polyamide resin and glass fiber, the pellet preparation method, etc. are as follows. A] Evaluation method of resin composition and molded article (1) Average glass fiber diameter, average aspect ratio, and glass fiber content with aspect ratio of 5 or less in resin composition: pellet of polyamide resin composition in formic acid Get in,
Dissolve the polyamide and precipitate the glass fibers. The obtained precipitate was observed under an optical microscope and randomly selected 3
The length and diameter of 00 to 1000 glass fibers were measured using an image analyzer IP-1000 manufactured by Asahi Kasei Corporation to determine the weight average fiber length and the number average fiber diameter. From the obtained results, the number average fiber diameter was defined as the average fiber diameter, and the value obtained by dividing the weight average fiber length by the number average fiber diameter was defined as the average aspect ratio. The content ratio of glass fibers having an aspect ratio of 5 or less was determined from distribution data of fiber length and fiber diameter. (2) Crystallization temperature: In the case of a polyamide resin composition, pellets or pulverized products of the raw material polymer used as a sample,
In the case of a polyamide resin molded product, a molded product obtained by evaluating the tensile properties described later (3) is cut into about 3 mm square to obtain a sample,
After holding at a temperature of melting point + 20 ° C. for 5 minutes using a differential thermal analyzer DSC7 manufactured by Perkin Elmer, the peak top temperature of the crystallization peak in the differential thermal analysis chart measured at a temperature lowering rate of 20 ° C./min is defined as did. (3) Tensile properties: Using an IS50EP injection molding machine manufactured by Toshiba Machine Co., Ltd., a test piece was obtained by appropriately adjusting the injection pressure and speed so that the filling time was about 1 second at a cylinder temperature of 290 ° C. . The mold temperature was appropriately set in the range of 80 to 120 ° C. according to the glass transition temperature of the composition. Using the obtained test piece, tensile strength according to ASTM D638,
The tensile elongation was measured. (4) Bending properties: Test pieces were obtained in the same manner as the test pieces used for the tensile properties of (3), and the bending strength and the flexural modulus were measured according to ASTM D790.

In the evaluation of the bending characteristics during water absorption, the test pieces were conditioned in an atmosphere of 23 ° C. and 50% relative humidity until the moisture content of the molded article reached equilibrium, and then measured. (5) Izod impact strength: A test piece was obtained in the same manner as the test piece used for the tensile properties of the above (3), and the notched Izod impact strength was measured according to ASTM D256. (6) Surface gloss: using an IS150E injection molding machine manufactured by Toshiba Machine Co., Ltd., setting the cylinder temperature to 290 ° C. and adjusting the injection pressure and speed as appropriate so that the filling time is about 1.5 seconds, and measuring 100 × 90 × 3 mm. A flat test piece was obtained. still,
The mold temperature was appropriately set in the range of 80 to 120 ° C. according to the glass transition temperature of the composition. Further, in order to evaluate surface glossiness with higher sensitivity, 2.5 parts by weight of carbon black nylon masterbatch F-36600B manufactured by Dainippon Ink Co., Ltd. per 100 parts by weight of the polyamide resin composition pellets of the present invention. -20S was blended before injection molding to obtain a black colored molded product.

The center of the obtained test piece was measured for Gs 60 ° according to JIS-K7150 using a handy gloss meter IG320 manufactured by Horiba. (7) Surface smoothness: The occurrence of undulation on the surface was visually evaluated using the flat test piece described in (6) above. The evaluation criteria were。 when no undulation was observed over the entire surface, ○ when the undulation was extremely or partially observed, and X when the undulation was significantly observed over the entire surface. (8) Surface roughness: the plate-shaped test piece according to the above (6),
The surface roughness Ra (center line average roughness) and Rmax (maximum height) were measured by JIS using a surface roughness measuring device SE30K and a surface roughness analyzer AY-31 manufactured by Kosaka Laboratory Co., Ltd.
B0601. The larger the value of both Ra and Rmax, the greater the surface roughness. (9) Weather resistance: The plate-shaped test piece described in (6)
Xenon Weatherometa, Xnotest, manufactured by TLAS
Accelerated exposure was performed using 1200 LM under the conditions of 83 ° C., 300 hours, and a rain cycle of 10 minutes / 60 minutes. The color difference (ΔE) before and after exposure was determined using a color difference meter ND-300A manufactured by Nippon Denshoku Co., Ltd. The smaller the color difference (ΔE), the better the weather resistance. (10) The average glass fiber diameter, the average aspect ratio, and the glass fiber content of the aspect ratio of 5 or less in the molded article:
The measurement was performed in the same manner as in the evaluation method (1) except that the flat molded product described in the evaluation method (6) was cut into a sample of about 3 mm square to obtain a sample. B] Polyamide resin and glass fiber used (1) Polyamide resin Nylon 66: Leona 1300 nylon 6 manufactured by Asahi Kasei Kogyo Co., Ltd. SF1013A nylon MXD6 manufactured by Ube Industries, Ltd .: Reny 6002 manufactured by Mitsubishi Engineering-Plastics Corporation Nylon 66 / 6I copolymer: produced according to Production Examples 1 to 3.

Nylon 46: Nylon 46C2000 manufactured by Teijin Limited (2) Glass fiber CS03MA416 manufactured by Asahi Fiber Glass Co., Ltd. Average fiber diameter: 13 μm Prototype material manufactured by Asahi Fiber Glass Co., Ltd. Average fiber diameter: 18 μm Asahi Fiber Glass ( Co., Ltd. CS03TA416 Average fiber diameter 23 μm Asahi Fiberglass Co., Ltd. Prototype material Average fiber diameter 28 μm Asahi Fiberglass Co., Ltd. Prototype material Average fiber diameter 36 μm C] Method for preparing pellets of polyamide resin composition Various polyamide resins and glass fibers were appropriately combined and melt-kneaded using a twin screw extruder TEM35 manufactured by Toshiba Machine Co., Ltd. to obtain pellets.

At this time, in order to adjust the aspect ratio of the glass fiber in the obtained pellet, the feed position, discharge amount (range of 30 to 90 kg / hr) and temperature (25%) of the glass fiber are used.
Screw rotation speed (250-4 ° C)
(Range of 50 rpm) was appropriately selected.

[0028]

[Production example] (Production example 1 of nylon 66 / 6I copolymer)
Equimolar salt of adipic acid and hexamethylenediamine 2.0
kg, 0.5 kg of equimolar salt of isophthalic acid and hexamethylenediamine and 2.5 kg of pure water were charged into a 5-liter autoclave and sufficiently purged with nitrogen. The temperature was raised from room temperature to 220 ° C. in about 1 hour while stirring was continued. Thereafter, the internal pressure of the autoclave is reduced to 1
The temperature was raised to 260 ° C. over about 2 hours while removing water from the reaction system so as to be 8 kg / cm 2 -G. Thereafter, the heating was stopped, the autoclave was closed, and the mixture was cooled to room temperature over about 8 hours to obtain about 2 kg of a nylon 66 / 6I (composition weight ratio: 78.5 / 21.5) polymer. The obtained polymer was pulverized and subjected to solid-phase polymerization at 200 ° C. for 10 hours under a nitrogen stream using a 10-liter evaporator to further increase the molecular weight. Sulfuric acid relative viscosity η by solid state polymerization
r increased from 1.38 to 2.30. (Production Example 2 of Nylon 66 / 6I Copolymer) 2.0 kg of equimolar salt of adipic acid and hexamethylenediamine and 0.32 of equimolar salt of isophthalic acid and hexamethylenediamine
kg and 2.32 kg of pure water were charged into a 5 liter autoclave and sufficiently purged with nitrogen. The temperature was raised from room temperature to 220 ° C. in about 1 hour while stirring was continued. After that, the internal pressure of the autoclave is reduced to 18 kg.
The temperature was raised to 260 ° C. over about 2 hours while removing water from the reaction system so as to be / cm 2 -G. Thereafter, the heating was stopped, the autoclave was closed, and the mixture was cooled to room temperature over about 8 hours, and then nylon 66 / 6I (composition weight ratio: 85
/ 15) About 2 kg of polymer was obtained. The obtained polymer was pulverized and subjected to solid-phase polymerization at 200 ° C. for 10 hours under a nitrogen stream using a 10-liter evaporator to further increase the molecular weight. The sulfuric acid relative viscosity ηr increased from 1.38 to 2.30 due to solid-state polymerization. (Production Example 3 of Nylon 66 / 6I Copolymer) 2.426 kg of equimolar salt of adipic acid and hexamethylenediamine and equimolar salt of isophthalic acid and hexamethylenediamine 0.
074 kg and pure water 2.5 kg were charged into a 5-liter autoclave and sufficiently purged with nitrogen while stirring well. The temperature was raised from room temperature to 220 ° C. in about 1 hour while stirring was continued. Thereafter, the internal pressure of the autoclave is reduced to 1
The temperature was raised to 260 ° C. over about 2 hours while removing water from the reaction system so as to be 8 kg / cm 2 -G. Thereafter, the heating was stopped, the autoclave was closed, and the mixture was cooled to room temperature over about 8 hours to obtain about 2 kg of nylon 66 / 6I (composition weight ratio: 97/3) polymer. The obtained polymer was pulverized and subjected to solid-phase polymerization at 200 ° C. for 10 hours under a nitrogen stream using a 10-liter evaporator to further increase the molecular weight. The relative viscosity ηr of sulfuric acid is 1.
It increased from 38 to 2.30.

[0029]

Example 1 Nylon 66 / 6I pulverized product obtained by the method shown in Production Example (Production of Nylon 66 / 6I Copolymer 1) was used as a main feed port of a twin screw extruder TEM35 manufactured by Toshiba Machine Co., Ltd. Thus, the glass fiber (CS03TA416) was supplied from the side feed port so as to have a composition ratio shown in Table 1.
Feeding by constant weight feeder, discharge rate 50kg / hr,
Cylinder temperature setting 290 ° C, screw rotation speed 450
The mixture was melt-kneaded at rpm to obtain pellets. Table 1 shows the evaluation results of the obtained pellets and molded articles using the pellets.

[0030]

Example 2 Pellets were obtained in the same manner as in Example 1 except that the pulverized nylon 66 / 6I obtained by the method shown in the Production Example (Production of Nylon 66 / 6I copolymer 2) was used.
Table 1 shows the evaluation results of the obtained pellets and molded articles using the pellets.

[0031]

Examples 3 to 11 Pellets and test pieces made of the compositions shown in Tables 1 to 3 were prepared, evaluated, and the evaluation results are shown in Tables 1 to 3.

[0032]

Example 12 Nylon 66 / 6I pulverized product and glass fiber (CS03TA416) obtained by the method shown in the Production Example (Production of Nylon 66 / 6I Copolymer 1) were twin-screw extruded from Toshiba Machine Co., Ltd. From the main feed port of the TEM35 machine, feed by a constant weight feeder so as to have the composition shown in Table 1, discharge rate 50 kg / hr, cylinder temperature 29
The mixture was melt-kneaded at 0 ° C. and a screw rotation speed of 250 rpm to obtain pellets. Table 4 shows the obtained pellets and the evaluation results of the molded articles using the pellets.

Each of the above-mentioned compositions of Examples 1 to 12 has almost no undulation on the surface of the molded piece, excellent mechanical properties, and a good balance of appearance, mechanical properties and weather resistance. Is clear from Tables 1 to 3. Comparing the evaluation results of Examples 1 and 12, the content of the glass fiber having an aspect ratio of 5 or less exceeds 15%.
It is understood that No. 2 is inferior in notched Izod characteristics.

Further, comparing the evaluation results of Example 1 and Example 10, Example 1 using nylon 66 / 6I is more excellent in terms of tensile elongation and notched Izod characteristics. In addition, as shown by the evaluation results of Example 1 and Examples 6 to 10, when the average glass fiber diameter is 20 to 25 μm and the average aspect ratio is 12 to 19, the mechanical properties, surface smoothness, and weather resistance are particularly high. Excellent balance.

[0035]

Comparative Example 1 Pellets were obtained in the same manner as in Example 1 except that the pulverized nylon 66 / 6I obtained by the method shown in Production Example (Production of Nylon 66 / 6I Copolymer 3) was used.
Table 4 shows the obtained pellets and the evaluation results of the molded articles using the pellets.

[0036]

Comparative Examples 2 to 7 Pellets and test pieces comprising the compositions shown in Tables 4 and 5 were prepared and evaluated. The evaluation results are shown in Tables 4 and 5. In any of the compositions in these comparative examples, the surface of the obtained molded product has undulation, or those having no undulation have poor mechanical properties, particularly impact resistance and / or weather resistance. It is clear from Tables 4 and 5 that the balance between appearance, mechanical properties and weather resistance is poor.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

[0042]

As described above in detail, the polyamide resin composition according to the present invention and the molded article made therefrom have higher mechanical properties (particularly impact resistance) and appearance properties (surface gloss) than the conventional ones. , Smoothness, and roughness) and weather resistance are significantly improved.

Claims (7)

[Claims] 1. A composition comprising 30 to 70% by weight of a polyamide resin having a crystallization temperature of 210 ° C. or lower and 70 to 30% by weight of a glass fiber, wherein the glass fiber has an average aspect ratio of 10 to 10.
20. The polyamide resin composition having an average fiber diameter of 15 to 30 μm. 2. The polyamide resin composition according to claim 1, wherein the content of glass fibers having an aspect ratio of 5 or less is 15% by weight or less of the total glass fiber content. 3. A polyamide resin comprising (a) 70 to 95% by weight of a hexamethylene adipamide component obtained from adipic acid and hexamethylene diamine and (b) a hexamethylene isophthalamide component obtained from isophthalic acid and hexamethylene diamine. 3. The polyamide resin composition according to claim 1, which is a copolymer comprising 30 to 5% by weight. 4. A glass fiber comprising 30 to 70% by weight of a polyamide resin and 70 to 30% by weight of a glass fiber, wherein the glass fiber has an average aspect ratio of 9 to 18 and an average fiber diameter of 15 to 3%.
0 μm, and the crystallization temperature of the polyamide resin is 210
A polyamide resin molded product having a temperature of at most ℃. 5. The polyamide resin molded article according to claim 4, wherein the content of glass fibers having an aspect ratio of 5 or less is 15% by weight or less of the total glass fiber content. 6. A polyamide resin comprising: (a) 70 to 95% by weight of a hexamethylene adipamide component obtained from adipic acid and hexamethylene diamine; and (b) a hexamethylene isophthalamide component obtained from (b) isophthalic acid and hexamethylene diamine. The polyamide resin molded product according to claim 4 or 5, which is a copolymer comprising 30 to 5% by weight. 7. The polyamide resin molded product according to claim 4, wherein the polyamide resin molded product is an injection molded product.