JPS62116661A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having good injection moldability and excellent mold release characteristics and suitable for use as a molding material giving thin-wall moldings having a complicated shape, by blending a polyamide resin with a specified polyalkylene ether glycol. CONSTITUTION:The titled compsn. is obtd. by blending 100pts.wt. polyamide resin (e.g., nylon 12, etc.) with 0.01-5pts.wt. polyalkylene ether glycol having an average MW of 300-3,000 (e.g., polyethylene glycol, etc.). The compsn. has good injection moldability, particularly excellent mold release characteristics without detriment to mechanical properties inherent to polyamide. The compsn. can be used as a molding material for the production of conventional moldings as well as thin-wall moldings having a complicated shape, such as clocks, cassette decks, video decks, printers, precision gears, etc.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention can be manufactured easily and inexpensively, and has good moldability and mold release properties without impairing the excellent mechanical properties inherent to polyamide. The present invention relates to a polyamide resin composition.

(Prior Art and Problems) Polyamide has conventionally been used as an engineering plastic in various precision molded products because of its excellent mechanical and chemical properties. However, when molding a molded product that is thin and has a complicated shape, such as a watch gear, there is a major problem in mold releasability.

Prolonging the cooling time to improve mold releasability will reduce molding efficiency, and the commonly used method of applying silicone-based mold release agents, etc. inside the cavity, The mold release effect decreases, causing molding variations,
This leads to variations in product quality.

On the other hand, it is also known to add silicone oil or fatty acids and fatty acid esters to polyamide in advance and knead them for the purpose of improving mold release properties, but these additives have relatively small molecules and do not interact with polyamide. Because of their poor compatibility, they tend to leak into the weld area, reducing weld strength and reducing the impact strength and tensile strength of molded products.

Therefore, the present invention aims to improve the mold releasability of thin-walled and complex-shaped molded products without reducing their mechanical strength (as described above).
As a result of extensive studies, we have found that a polyamide resin composition for index molding that satisfies the required performance of h and id can be created by combining a polyamide resin and polyalkylene ether glycol having a limited average molecular distance. As a result, we have arrived at the present invention.

(Means for Solving the Problem) That is, the present invention is to add one or more polyalkylene ether glycols having an average molecular weight of 300 to 50oO to 1 part of 100 parts of polyamide resin. - A polyamide resin composition containing 5 or more parts.

Polyamide in the present invention is nylon 6, nylon 6
．． 6, nylon 6.10, nylon.

12.1 Ylon 11, Nylon 12, copolymers containing the above-mentioned nylon monomers as main components, and mixtures of these polymers. Examples of copolymers include polyamides such as polyetheresteramide or polynyfluamide, which are copolymers with soft logments, such as polytetrahydrofuran or polytetrahydrofuran in which both terminal groups have been modified with amino groups or carfoyacyl groups. There is an elastomer. Preferably, nylon 11, nylon 12, or polyamide containing these heptads as a main component, which have little change in physical properties due to moisture absorption, are preferably used.

The polyfulkylene ether glycol used in the present invention has an alkyl group having 2 or more carbon atoms and 10 or more carbon atoms, and polyethylene glycol, polypropylene glycol, boriatramethylene ether glycol, or a mixture thereof can be suitably used. . The average molecular weight of these polyalkylene glycols is 300 or more and 5000 or less, preferably 500 or more and 2000 or less F.
It is. If the molecular weight is 200 or less, the mold releasability will be improved, but there is a risk that the weld strength and impact strength of the molded product will be reduced. When the average molecular weight exceeds 5,000, the effect of improving mold releasability decreases.

When blending these polyalkylene ether glycols into the above-mentioned polyamide, one type or a mixed system of two or more types may be used. It is preferably 011 parts or more and 2 parts or less. Its blending amount is 0.
If the amount is less than 0.011 parts, the mold releasability will not be improved, and if it is more than 5 parts, the mold releasability will be improved, but the weld strength and impact strength of the molded product will be reduced.

Further, commonly used resin additives such as antioxidants, plasticizers, ultraviolet absorbers, nucleating agents, etc. can be added to the polyamide resin composition.

(Effects of the Invention) The polyamide resin composition of the present invention has good injection moldability without impairing the mechanical properties inherent to polyamide, and is particularly excellent in mold releasability. Suitable for use as molding feed for molded products with thin walls and complex shapes, such as watches, cassette decks, video decks, precision gills for printers, printer shuttlecocks, etc., as well as general molded products. Things can happen.

(Examples) The present invention will be explained below with reference to Examples, but the present invention is not limited by these Examples.

Examples 1 to 2 Plasticized nylon 12 (Die manufactured by Ruhuls: Diamil: I-1724) Average molecular l in 100 weight X'li part
Mix Pt400 polyethylene glycol, 30.
The mixture was kneaded and pelletized using a φ twin-screw extruder.

Using this pellet, the diameter is 10 mrn and the thickness is 7 m.
A watch 1-17-m was molded, and the quality of the mold releasability was determined.

If the mold releasability is poor, warpage will occur in the gear V-.

On the other hand, a test piece was injection molded using a weld-forming gold having the shape of a J15K6301.3-shaped dumbbell having a thickness of 1M, and the weld strength retention rate was measured.

The results are not shown in Table-1.

Example 3 The average molecule 53 of the polyethylene glycol of Example 1 is 1
The test was conducted in the same manner as in Example 1, except that the test temperature was 500.

The results are shown in Table-1.

Example 4 Test was carried out in the same manner as in Example 1 except for using boriatramethylene ether glycol (manufactured by Hodogaya Chemical Co., Ltd.: p T G 1oo) with an average molecular weight of 850 instead of the polyethylene glycol in Example 1. I did it.

The results are shown in Table-1.

Example 5 A test was conducted in the same manner as in Example 4, except that the average molecular weight of polytetrameblene glycol in Example 4 was 2000.

The results are not shown in Table-1.

Example 6 The polyamide resin of Example 3 was composed of unplasticized polyamide (manufactured by Daicel Huls: L1600) and polyneedle ester amide (manufactured by Daicel Huls: PAE E62MS).
The test was conducted in the same manner as in Example 3, except for 1, which was a blend with -3).

The results are shown in Table-1.

Comparative Example 1 A test was conducted in the same manner as in Example 1 using only the plasticized nylon 12 of Example 1.

The results are shown in Table-1.

Comparative Example 2 The average molecular weight of the polyethylene glycol of Example 1 was 20
The test was conducted in the same manner as in Example 1, except for 0 and 1.

The results are shown in Table-1.

Comparative Example 3 The average molecular end of the polyethylene glycol of Example 1 was 60
The test was conducted in the same manner as in Example 1 except for 1 which is 00.

The results are shown in Table-1.

Comparative Example 4 A test similar to Example 1 was conducted using polydimethylsilokinane (30,000 cs) instead of polyethylene glycol in Example 1.

The results are shown in Table-1.

Claims (1)

[Claims] A polyamide resin composition comprising 0.01 parts by weight or more and 5 parts by weight or less of one or more polyalkylene ether glycols having an average molecular weight of 300 or more and 5,000 or less in 100 parts by weight of a polyamide resin.