JPH0269561A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To provide a polyamide resin composition having excellent moldability and molding appearance without deteriorating the thermal and mechanical characteristics thereof and suitable for electric and electronic parts, etc., by compounding the zinc compound of a specific aliphatic carboxylic acid in a specified amount. CONSTITUTION:(C) 0.05-2 pts.wt., preferably 0.1-1 pt.wt., of the zinc compound of a 10-36C aliphatic carboxylic acid is compounded with 100 pts.wt. of a composition comprising (A) 75-25wt.% of a polyamide (e.g., nylon 4, 6 or 7) having a relative viscosity of 2-3.5 measured on JIS 6810 and (B) 25-75wt.% of a fibrous reinforcing material (e.g., glass fibers or carbon fibers) having a diameter of 0.001-0.05mm and a length of 0.005-10mm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyamide resin composition. For more information,
The present invention relates to fiber-reinforced polyamide resin compositions with good appearance.

[Conventional technology]

Polyamide resin has excellent thermal and mechanical properties and is used in a wide range of fields such as electrical and electronic parts, mechanical parts, and automobile parts. In particular, polyamide resins reinforced with fibrous reinforcing materials such as glass fibers and carbon fibers are used for functional and structural parts because they have significantly improved strength, rigidity, and heat resistance.

[Problem that the invention seeks to solve]

However, when reinforcing polyamide resin with a fibrous reinforcing material, there is a problem in that as the amount of reinforcing material increases, the fluidity of the resin deteriorates during melt processing, resulting in a significant decrease in moldability. . In addition, it has the disadvantage that the appearance of the resulting product deteriorates, significantly impairing its commercial value. This tendency becomes noticeable when the amount of reinforcing material added exceeds 30%, and when it exceeds 45%, it becomes extremely difficult to obtain a good appearance. These drawbacks can be overcome by reducing the amount of fibrous reinforcing material, but in that case the reinforcing effect becomes insufficient and the desired high mechanical properties cannot be obtained.

For this reason, in order to obtain good appearance and processability, attempts have been made to lower the molecular weight of polyamide resin as much as possible or to add plasticizers to it, but both methods reduce the mechanical and The range of application is limited because it significantly impairs thermal properties.

Therefore, it is possible to create a polyamide resin composition that is reinforced by incorporating a large amount of fibrous reinforcing material, has excellent moldability, has a good appearance, and has excellent mechanical properties, and is industrially easy. The reality is that it has not been obtained using a suitable method.

[Means for solving problems]

In view of the above-mentioned problems, the inventors of the present invention have made intensive studies and have developed a fiber-reinforced polyamide that has good moldability and a good appearance by incorporating a specific zinc compound of aliphatic carboxylic acid. The present invention was achieved by discovering that a resin can be obtained.

That is, the gist of the present invention is that 75 to 25% by weight of a polyamide resin with a relative viscosity value of 2 to 3.5 measured in accordance with JIS K6810, and 25 to 75% by weight of a fibrous reinforcing material.
10 to 3 carbon atoms per 100 parts by weight of a composition consisting of
The polyamide resin composition contains 0.05 to 2 parts by weight of a zinc compound of aliphatic carboxylic acid No. 6.

The present invention will be explained in more detail below.

The polyamide resin used in the present invention includes 3
Polyamide resins obtained by polycondensation of lactams having more than one ring member, polymerizable ω-amino acids, dibasic acids, and diamines can be used.

Specifically, ε-caprolactam, aminocaproic acid,
Those obtained by polymerizing enantholactam, 7-aminohbutanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piperidone, etc., or hexamethylenediamine, nonamethylenediamine, undecamethylene Polymers obtained by polycondensing diamines such as diamine, dodecamethylene diamine, metaxylylene diamine, and dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, cepatic acid, dodecanibasic acid, and geltaric acid, or polymers thereof. Copolymers, such as nylon4. 6. 7. 8. 11. 12.6
・6,6・10.6・11.6・12,6T, 6/6・
Examples include 6.6/12.6/6T and 61/6T.

The relative viscosity of the polyamide resin is selected from a value of 2 to 3.5 as measured in accordance with JIS K6810. If the relative viscosity is lower than 2, the mechanical strength will decrease, and if it exceeds 3.5, the appearance of the resulting molded product will deteriorate.

The fibrous reinforcement materials used in the present invention include glass fibers, carbon fibers, titanium oxide whiskers, gypsum fibers, ceramic fibers, inorganic fibrous reinforcements such as asbestos, metal fibers such as copper, aluminum, and stainless steel, and polyamide resins. Examples include organic fibers having a melting point higher than the molding temperature. Among these, it is industrially preferable to use glass fiber, carbon fiber, or ceramic fiber. There is no particular limitation on the shape of the reinforcing material, but generally the diameter is 0.001 to 0.05 mm and the length is 0.001 to 0.05 mm.
．． 005-10m is preferable.

The blending ratio of the polyamide resin and the fibrous reinforcing material is 75 to 25% by weight for the polyamide resin and 25% by weight for the fibrous reinforcing material.
~75% by weight. When the amount of the fibrous reinforcing material is less than 25% by weight and 1% by weight, no appearance improvement effect is observed due to the aliphatic carboxylic acid zinc compound of the present invention, and when it exceeds 75% by weight, molding becomes difficult. In addition, well-known inorganic fillers such as silica, alumina, silica-alumina clay minerals, silica-magnesium clay minerals, calcium silicate, and calcium carbonate may be blended together with the fibrous reinforcing material.

The aliphatic carboxylic acid zinc compound used in the present invention is an aliphatic carboxylic acid having a carbon number lθ to 36, preferably 12 to 24, and more preferably a saturated aliphatic monocarboxylic acid. Specifically, they are zinc salts such as decanoic acid, lauric acid, myristic acid, valmitic acid, stearic acid, behenic acid, oleic acid, elaidic acid, and montanic acid, and their blending ratio is the same as that of polyamide resin and fibrous reinforcing material. 0.05 to 100 parts by weight of resin consisting of
2 parts by weight, preferably in the range of 0.1 to 1 part by weight. If the amount is less than 0.05 parts by weight, no appearance improvement effect will be observed, and if it exceeds 2 parts by weight, mechanical properties will be impaired.

In addition to the above-mentioned formulations, the composition of the present invention includes well-known additives,
For example, it may contain a lubricant, a nucleating agent, an antioxidant, a coloring agent, a flame retardant, an antistatic agent, a weatherability imparting agent, and the like. Also,
It is also possible to blend other resins within a range that does not impair the properties of the composition of the present invention.

The compositions of the present invention are mixed by methods well known to those skilled in the art, such as Banbury, extruders, supermixers, and the like. Among these, melt mixing using a kneading extruder is preferred.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these unless it departs from the gist thereof.

Examples 1 to 9 The polyamide resin had a relative viscosity of 2.2% measured by adding 4% to JTS K6810. 2.5. 3゜3
Three types of nylon 6 resin (manufactured by Mitsubishi Kasei Corporation, product name: NOVAMI D), and a relative viscosity of 3.0
A commercially available glass fiber (manufactured by Asahi Fiberglass Co., Ltd., trade name: MA486) and/or carbon fiber was used as a fibrous reinforcing material. (Manufactured by Toho Heslon Co., Ltd., product name: C
06), and mixed zinc stearate as a zinc compound of aliphatic carboxylic acid at the compounding ratio shown in Table 1, and heated the resin at a temperature of 250 to 270°C in a bent two single-screw extruder with a screw diameter of 4Q+U. The mixture was melted and mixed to obtain a pellet. The pellet thus obtained was heated at 120°C for 6 hours.
It was vacuum dried and injection molded using an injection molding machine with a mold clamping force of 100 tons to obtain a test piece, and its tensile strength, bending strength, and bending elastic modulus were measured. In addition, the glossiness of the obtained test piece was measured and the surface appearance was evaluated. The injection pressure required for injection molding was also measured. The results are shown in Table-2.

Comparative Examples 1 to 3 The same procedures as Examples 1 to 9 were carried out except that the zinc compound of aliphatic carboxylic acid was not blended and the blending ratio of each component was changed as shown in Table 1. The results are shown in Table-2.

Comparative Example 4 The same procedure as Examples 1 to 9 was carried out except that the amount of the fibrous reinforcing material was changed as shown in Table 1. The results are shown in Table-2.

Comparative Example 5 Comparative Examples 1 to 3 were carried out, except that the amount of the fibrous reinforcing material was changed as shown in Table 1. The results are shown in Table-2.

Comparative Examples 6 to 8 Barium stearate and calcium stearate were used instead of the zinc compound of fatty acid carboxylic acid.
It was carried out in the same manner as Examples 1-9. The results are shown in Table-2.

The methods for measuring various physical properties in the above examples are as follows.

Tensile strength: Tested in accordance with ASTD D638.

Bending strength: Conducted in accordance with ASTD D790.

Flexural modulus: Performed in accordance with ASTD D790.

Glossiness: Measured at an angle of 60 degrees in accordance with JIS 28741.

/ [Effects of the Invention] In the polyamide resin composition of the present invention, moldability is significantly improved without impairing thermal and mechanical properties,
The appearance of the obtained molded product is also good.

Therefore, it is suitably used in a wide range of fields such as electrical/electronic parts, mechanical parts, automobile parts, functional parts, and structural parts.

applicant

Claims (1)

[Claims] (1) 75 to 25% by weight of a polyamide resin with a relative viscosity value of 2 to 3.5 measured in accordance with JIS K6810;
Composition 100 consisting of 25-75% by weight of fibrous reinforcement
A polyamide resin composition containing 0.05 to 2 parts by weight of a zinc compound of an aliphatic carboxylic acid having 10 to 36 carbon atoms.