JPS6088066A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To provide a compsn. which gives lamellar moldings which have excellent mechanical properties and little suffer environmental stress cracking caused by metal halides, by mixing two aliph. polyamides having a specified ratio of the number of methylene groups to that of amide groups and a specified relative viscosity ratio. CONSTITUTION:A polyamide resin compsn. consists of 10-90pts.wt. aliph. polyamide (A) in which the ratio of the number of methylene groups to that of amide groups in the main polymer chain is 4-5, and 90-10pts.wt. higher aliph. polyamide (B) in which the ratio of the number of methylene groups to that of amide groups is 6-11, and has a ratio of the relative viscosity of A to that of B of 1.16-2.70. Optionally, other polymers and additives such as colorant, antioxidant, thermal stabilizer, ultraviolet light absorber, antistatic agent, lubricant, plasticizer, flame retarder, etc. may be added to the compsn. according to purpose, so long as the desired properties are not deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyamide tsukuzai composition that has less environmental stress cracking due to 6, more specifically 4 halides on gold, and
The present invention also relates to a polyamide 4111 resin composition that provides a single-layer molded article with excellent mechanical properties.

Due to its toughness, electrical properties, and thermal properties, polyamide is widely used as parts for automobiles and electrical products. - Nylon 6 obtained by Nl silicon polymerization of caprolactam and nylon 66 obtained by polycondensation reaction of hexamethylene diamine and adipic acid have a serious drawback of environmental stress cracking caused by metal halides. It is known that contact with calcium chloride causes cracks in polyamide resin molded products and causes deterioration of the molded products.

In order to improve this environmental stress cracking, research has been carried out, and it is known that it is effective to blend high-grade fat "Kai-polyamide" into nylon 66.
80449,! r￥ Kaisho 57-212252).

During this time, the present inventors also worked diligently to improve Ω, and as a result, when blending 1YHj class aliphatic polyamide [13] with Ka'd aliphatic polyamide [A], [N] and (
It has been found that specifying the molecular weight (relative solution viscosity) of B) has a significant effect on this improvement3. Being there is a magnification of 14
Ij (a) is recognized in the micrograph at 2x magnification, and the present invention makes this layered material effective in improving the environmental stress color and fg.

That is, the present invention provides an aliphatic polyamide (Au10 to 90 parts by weight and (Cl-12
/N1-IC0) is 6 to 11 higher aliphatic polyamide C
B) A polyamide consisting of 90 to 10 parts by weight and having a relative viscosity ratio of polyamide (A) and [B] (relative viscosity of [A]/relative viscosity of [B]) of 1.16 to 2.70. This invention relates to a resin composition.

The polyamide resin composition of the present invention is a composition consisting of two types of aliphatic polyamides, and this type is characterized by the ratio of the number of methylene groups to the number of amide groups in the polymer main chain (Cl-12/
NHCO). Aliphatic polyamide [
A] is a polyamide in which (CH2/NlIC0) is 4 to 5. Examples of such polyamide include nylon 4, nylon 6, nylon 46, nylon 66, etc., or mixtures and copolymers thereof.

Higher aliphatic polyamide (B) is (CH2/NHCO)
is 6 to 11. Such polyamides include (rl, nylon 11, nylon 12, nylon 69, nylon 610, nylon 612, nylon 613, etc., or mixtures and copolymers thereof.

In [A], methylene group in the main chain! , when the ratio of z and the number of amide groups is 4 less than a, then in [13] the ratio of 7 is 1
In any case, the combination of 2 or more is (A,) and [+(]
The relative viscosity ratio of the aliphatic polyamide CA used in the present invention (1) and the higher aliphatic polyamide [13] is between 1.16 and 2.
70, preferably 1-50 to 2.50. 1
．． If it is less than 16, the contribution of the metal halide to improving resistance to boundary stress cracking is insufficient;
If it exceeds 70, extrusion and molding properties are poor and it is not practical. Further, the relative viscosity of the aliphatic polyamide (A) may be a commonly used viscosity, but is preferably 3.5 to 5.0, and more preferably 4.0 to 5.0. 5.0. .

The relative viscosity here refers to the relative viscosity measured based on JIS K-68101. The polyamide resin composition of the present invention is composed of aliphatic polyamide (
The viscosity ratio of A) and higher aliphatic polyamide [B] is 1.16
~2.70, polyamide [A110~
90 parts by weight, preferably 30 to 60 parts by weight, and polyamide [
B] 90 to 10 parts by weight, preferably 70 to 40 parts by weight.

If the amount of aliphatic polyamide C, B) in the composition is less than 10 parts by weight, the improvement against environmental stress cracking caused by metal halides will not be sufficient, and if it exceeds 90 parts by weight,
The mechanical properties of the aliphatic polyamide (A) are reduced.

The composition of the present invention can be manufactured by well-known manufacturing methods. Examples include a method of melt blending in an extruder such as a conventional single-screw or twin-screw extruder, a method of blending by injection molding, and the like.

In addition, to the extent that the purpose of the present invention is not impaired, these compositions may further include other resin polymers, colorants, oxidative deterioration inhibitors, heat stabilizers, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, flame retardants, etc. can be added depending on the purpose.

In this way, the present invention is extremely distinctive. That is.

Previously published documents (JP-A-57-80449, JP-A-57-212252) describe aliphatic polyamide [A]
It has been shown that higher aliphatic polyamide CB) is blended into J
However, the relative viscosity ratio of [A''] and [:B] is not mentioned.

On the other hand, in the present invention, [A] 1O-=90, preferably 30 to 60 parts by weight, and (B) 90 to 10, preferably 7
In a compounding composition consisting of 0 to 40 parts by weight, CA) and C
Setting the relative viscosity ratio of B) to 1.16 to 2.70,
This is a completely new invention that has been found to be highly effective against environmental stress cracks.

Next, the present invention will be specifically explained using examples.

Example-1 Relative viscosity ηr is 2.58.3.80.4.01.4.7
8 nylon 66 and relative viscosity ηr is 2.18.2.76
In the combination of nylon 610 shown in Table 1, nylon 610 was added to nylon 66 at a ratio of 60:40.

Blended using a tumbler type mixer. This mixture is TO
A polyamide resin composition was obtained by melt-kneading using an mnφ single-screw extruder. The obtained polyamide composition was molded into a test piece for measuring physical properties using an injection molding machine, and its resistance to environmental stress cracking was examined. The results are shown in Table 1.

Comparative Example-1 Nylon 66 with relative viscosity ηr of 2.58.4.78.6.00 and relative viscosity ηr of 1.70.2.26.2.76
Nylon 61G was combined as shown in Table 1, and nylon 610 was added to nylon 66 at a weight ratio of 60:4 to obtain a polyamide composition in the same manner as in Example 1. I looked into gender. The results are shown in Example 2: pellet-shaped nylon 66 (relative viscosity ηr = 4.
01) and pelletized nylon 612 (relative viscosity ηr
=2-22) to obtain a polyamide resin composition in the same manner as in Example-1. At this time, the weight ratio of nylon 66/nylon 6!2 was 15/85.25/75.35/
Compositions of 65°so, 'so, To/30.85/15 were prepared. The obtained polyamide composition was molded into a test piece for measuring physical properties using an injection molding machine, and the i-1 environmental stress cracking property and tensile strength were examined. The results are shown in Table 2.

Comparative Example-2 Using the same nylon 66 and nylon 612 as in Example-2, the weight ratio of nylon 66 and nylon 612 was 10010.9515.5/95.0/Zoo. A polyamide composition was obtained in the same manner as in Example-2, and evaluated in the same manner as in Example-2. The result is the second
Shown in the table.

Below margin

Claims (1)

[Claims] The ratio of the number of methylene groups to the number of amide groups in the polymer main chain (CH
2/Aliphatic polyamide CA whose NHCO) is 4 to 5
ll0~90 heavy de14 parts and (CH2/NHCO) is 6~
11 higher aliphatic polyamide [B] consisting of 5 parts of 90-10
Relative viscosity of / [Relative viscosity of J is 1.16 to 2-7
A polyamide resin composition characterized in that