JP3293148B2 - Polyamide resin composition - Google Patents

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 which is useful as an exterior material for electric parts and mechanical parts, and which is black and has a good appearance.

[0002]

2. Description of the Related Art Conventionally, a polyamide resin composition reinforced with glass fibers such as glass fiber reinforced nylon has been used.
Due to its excellent heat resistance and mechanical properties and good dimensional accuracy, it is widely used as a molding material for machine parts and the like.

However, when this composition is colored black, the appearance of the glass fibers is prominent and unevenness of gloss is conspicuous, and the appearance is poor. Therefore, the composition is not suitable for use as an exterior material such as electric parts and mechanical parts. there were.

[0004] For this purpose, polyamide resin compositions or other resins containing a filler as a reinforcing component are generally used for this type of application.

However, although these materials have no problem in appearance, they are not sufficiently satisfactory in mechanical properties.

[0006]

As described above, there is no known polyamide resin composition which is suitable for an exterior material, has a good appearance in black, and has excellent heat resistance and mechanical properties. Its development is strongly desired.

The present invention has been made to meet such a demand, and an object of the present invention is to provide a polyamide resin composition which is black, has a good appearance, and can sufficiently satisfy heat resistance and mechanical properties.

[0008]

The present inventors have conducted intensive studies to obtain such a polyamide resin composition. As a result, the present inventors have found that a suitable amount of a glass fiber having a specific fiber length and a specific carbon black can be mixed. The present inventors have found that the above objects can be achieved, and have completed the present invention.

That is, the polyamide resin composition of the present invention comprises: (A) 100 parts by weight of a polyamide resin;
20 to 130 parts by weight of glass fiber with an average fiber length of 0.1 to 0.4 mm ,
(C) It is characterized by containing 0.01 to 6 parts by weight of channel type carbon black.

[0010] As the component (A) of the polyamide resin used in the present invention are nylon 6, nylon 66, nylon 11, nylon 12, nylon 46, etc. xylylenediamine-based nylon. These alone one Or two or more of them may be used in combination. In the present invention, particularly preferably a polyamide resin having a relative viscosity of 1.8 to 3.5, more preferably a relative viscosity of 2.0
~ 2.8.

The glass fiber (B) used in the present invention has an average fiber length of 0.1 to 0.4 mm, preferably 0.1 to 0.4 mm.
It is 15mm to 0.3mm. If the thickness is less than 0.1 mm, the reinforcing effect is small and the mechanical properties are insufficient, and if it exceeds 0.4 mm, uneven gloss is caused and the appearance is poor. Incidentally, the shorter the fiber length, the higher the surface glossiness. The thickness of the fiber is not particularly limited, and a commonly used fiber having a diameter of about 5 to 15 μm can be used. It is also possible to use a glass fiber surface-treated with a coupling agent or a sizing agent for a polyamide resin. In the present invention, the amount of the glass fiber is 10 to 130 parts by weight, preferably 20 to 120 parts by weight, based on 100 parts by weight of the polyamide resin (A). If the compounding amount is less than 10 parts by weight, the reinforcing effect is small and the mechanical properties become insufficient, and if it exceeds 130 parts by weight, the moldability and appearance become poor.

Further, the channel type carbon black of the component (C) used in the present invention is for coloring the composition of the present invention black without lowering its surface glossiness. By using this channel type carbon black, it is possible to obtain a molded product having much better surface gloss than carbon black produced by the furnace method or another impact method. In other words, in other carbon blacks, even a small amount of about 0.1 part by weight per 100 parts by weight of the polyamide resin reduces the surface gloss sharply, but in the case of the channel type carbon black, the compound hardly reduces the gloss. . This is considered to be because the channel type carbon black has a very fine particle size of 35 μm, and the surface properties show a high affinity for the polyamide resin. In the present invention, the amount of the channel-type carbon black is 0.01 to 10 parts by weight, preferably 0.05 to 10 parts by weight, per 100 parts by weight of the polyamide resin (A).
6 parts by weight. If the amount is less than 0.01 part by weight, the blackness will be low, and if it exceeds 10 parts by weight, the impact strength will decrease.

The polyamide resin composition of the present invention contains an organic dye, preferably a nigrosine-based organic dye, in an amount of 100 parts by weight of the polyamide resin (A) in order to maintain high gloss and further increase blackness. Can be blended within a range not exceeding 1 part by weight. Such organic dyes greatly reduce brightness while maintaining high glossiness,
Increase blackness. If the amount of the organic dye exceeds 1 part by weight with respect to 100 parts by weight of the polyamide resin (A), the chemical resistance decreases.

Further, the polyamide resin composition of the present invention contains an antioxidant, an ultraviolet absorber, a plasticizer, a lubricant, an antistatic agent, a flame retardant, a release agent, and other coloring agents commonly used in polyamide resins. Additives such as agents can be blended according to the purpose and use.

The polyamide resin composition of the present invention is prepared by premixing the above components and kneading them in an extruder or kneader, or pellets obtained by previously kneading any number of components in an extruder or kneader. Further, it can be produced by an arbitrary method such as a method of melt-mixing the remaining components, a method of charging an arbitrary number of components from a hopper of an extruder, and a method of charging the remaining components from the middle of the extruder.

The polyamide resin composition of the present invention can be molded under ordinary polyamide resin molding conditions without using special molding methods and molding conditions. It is used in the form of a plate.

[0017]

The polyamide resin composition of the present invention is obtained by blending a suitable amount of glass fiber having a specific fiber length and a specific carbon black with a polyamide resin, thereby obtaining a black surface under ordinary molding methods and molding conditions. High gloss and excellent appearance,
In addition, it is possible to obtain molded articles having excellent heat resistance and mechanical properties. In addition to various molded articles, it is very useful as an exterior material for applications in which each of the above properties is particularly required, that is, electric parts and mechanical parts which are easily subjected to external force. Useful for

[0018]

The present invention will be described below with reference to examples. In the following text, “parts” and “%” indicate “parts by weight” and “% by weight”, respectively.

Examples 1 to 14 and Comparative Examples 1 to 5 A polyamide resin having a relative viscosity (RV) of 2.
2, 2.5, 4 kinds of nylon 6 (less 2.8,3.1, Ny6
), Nylon 66 having a relative viscosity of 2.5 (hereinafter referred to as NY6).
6) and a polyamide from meta-xylylenediamine and adipic acid (hereinafter abbreviated as MXD6),
Glass fiber (diameter 10.5 μm, length 3 mm), channel type carbon black (abbreviated as 40% polyethylene wax master channel CB), furnace type carbon black (abbreviated as 40% polyethylene wax master furnace CB), black dye A certain nigrosine dye was uniformly kneaded with the composition shown in Table 1 to obtain a compound chip.

The kneading method is as described in Examples 2 and 7 and Comparative Examples 3 and 5.
For each of Examples and Comparative Examples except for the above, after premixing all components, the mixture was put into a hopper of a twin-screw extruder, and when the polyamide resin was NY6, the temperature was 250 ° C.
℃, MXD6 It was carried out by a method of melt-kneading at a cylinder temperature of 270 ° C. For Examples 2 and 7, and Comparative Examples 3 and 5, a method was used in which the components except for the glass fibers were premixed, and then charged into a hopper of a twin-screw extruder, and the glass fibers were charged halfway into the extruder. . In addition, the latter method of introducing the glass fiber into the extruder halfway was performed in order to examine the dependence of the length of the glass fiber in the present invention. That is, the length of glass fiber in the obtained compound is different between the case where glass fiber is put into the extruder on the way and the case where all components are put into the hopper. You can know the difference of the effect depending on the length of.

Next, after drying each of the above compound chips to a moisture content of 0.1% or less, a flat test piece is injection molded at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. by an injection molding machine. The surface glossiness and blackness (brightness) of each of the test pieces were measured. The result is
The composition and the average fiber length of the glass fiber are shown in Table 1. The surface glossiness, blackness, and average fiber length of the glass fibers were measured by the following methods.

Surface glossiness: Measured by a 60-degree incident 60-degree reflection method according to ASTM D 2457 Blackness: Brightness at a wavelength of 457 μm using a color difference meter (white:
100, black: 0) Measured Average fiber length of glass fiber: Measure the length of glass fiber using a projector with a magnification of 100, and determine from the histogram with a class interval of 50 μm.

[0023]

[Table 1]

As is clear from the table, the test piece obtained from the polyamide resin composition according to the present invention has a high surface glossiness, a sufficient blackness, and an excellent appearance. In addition, those containing a black dye show higher blackness than those not containing the dye.

[0025]

As described above, according to the polyamide resin composition of the present invention, an appropriate amount of glass fiber having a specific fiber length and a specific carbon black are blended with the polyamide resin. It is possible to obtain a molded article which is black, has a high surface glossiness, is excellent in appearance, and is also excellent in heat resistance and mechanical properties. Therefore, the polyamide resin composition of the present invention is extremely useful not only for various molded products, but also for exterior materials such as electric parts and mechanical parts which have been inconvenient in conventional products.

[0026]

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 77/00-77/12 C08K 3 / 04,7 / 14

Claims (1)

(57) [Claims] 1. A glass fiber having an average fiber length of 0.1 to 0.4 mm and a glass fiber of 20 to 130 parts per 100 parts by weight of (A) a polyamide resin.
Parts by weight, (C) channel type carbon black 0.01-6
A polyamide resin composition comprising parts by weight.