JP2000351896A - Flame retardant polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which, when burned, does not pollute the environment and does not emit a toxic gas by blending a polyamide resin and a tetrazole compound having a decomposition temperature not lower than a molding temperature of the polyamide resin. SOLUTION: A polyamide resin is preferably polyamide 6, polyamide 66 or a copolymer of polyamide 6/polyamide 66 and further preferably polyamide 66. A tetrazole compound is preferably 1H-tetrazole, 5,5'-bis-1H-tetrazole, 5- methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, or their derivatives and further preferably 5,5'-bis-1H-tetrazole, 5-amino-1H-tetrazole, or their derivatives. Normally, 0.1-50 pts.wt. of a tetrazole compound is blended with 100 pts.wt. of a polyamide resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant polyamide resin composition used for parts such as connectors in the electronic and electric fields, electric parts in the automobile field, and others.

[0002]

2. Description of the Related Art Polyamide resins are used for various industrial parts because of their excellent heat resistance, mechanical properties and moldability. When used for these purposes, it is not uncommon for polyamide resins to be required to be flame-retardant. Therefore, a polyamide resin to which a halogen compound is added as a flame retardant to make the polyamide resin flame retardant has been used.

[0003]

However, the flame-retardant polyamide resin obtained by the above method has problems in environmental pollution due to dioxin and the like generated during combustion, toxicity of combustion gas, and the like. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a flame-retardant polyamide resin composition that is free from environmental pollution due to dioxin or the like during combustion and has no toxicity in combustion gas.

[0004]

As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by combining a specific tetrazole compound with a polyamide resin. Was completed. That is, the present invention provides a flame-retardant polyamide resin composition containing (A) a polyamide resin and (B) a tetrazole compound having a decomposition temperature not lower than the molding temperature of the polyamide resin.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polyamide resin of the present invention is generally a polymer compound having an acid amide bond (-CONH-) as a repeating unit, and is not particularly limited. , Polyamide 6, polyamide 11, polyamide 12, polyamide 4.6, polyamide 6.6, polyamide 610, polyamide 6.1
2, polyamide 6.6T, polyamide MXD6 and the like. Polyamide-based copolymer (for example, polyamide 6 / 6.6 copolymer, polyamide 6 / 6.10 copolymer, etc.) may be used, or two or more kinds may be used in combination. Among these, polyamide 6, polyamide 6.6, and polyamide 6 / 6,6 copolymer are preferable, and polyamide 6.6 is particularly preferable because high flame retardancy can be obtained.

[0006] The tetrazole compound used as a flame retardant in the present invention is a compound having a five-membered ring composed of 4 atoms of nitrogen and 1 atom of carbon, and has no environmental pollution such as dioxin generated during combustion. When thermally decomposed, only gases such as nitrogen, carbon dioxide and water vapor are generated. Among the tetrazole compounds, those compounds that generate a large amount of gas per gram of the compound when the compound is thermally decomposed are preferable in that high flame retardancy is obtained. As such a tetrazole compound, 1H-
1H of tetrazole or its metal salt, amine salt, etc.
-Tetrazole derivative or 5,5'-bis-1H
5,5′-bis-1H-tetrazole derivative such as tetrazole or its metal salt, amine salt or
5-methyl-1H-tetrazole or a metal salt thereof,
5-methyl-1H-tetrazole derivatives such as amine salts or 5-phenyl-1H-tetrazole or metal salts thereof, 5-phenyl-1H-tetrazole derivatives such as amine salts or 5-amino-1H-tetrazole or metals thereof 5-amino- such as salts and amine salts
And a 1H-tetrazole derivative. The tetrazole-based compound includes a 2H-tetrazole derivative which is a tautomer of a 1H-tetrazole derivative, but may be a 2H-tetrazole derivative in the present invention. Among these, 5,5′-bis-1H-tetrazole and its derivatives, or 5-amino-1H-tetrazole and its derivatives are particularly preferred. The tetrazole compound in the present invention may be added alone or in combination of two or more.

The flame-retardant polyamide resin composition of the present invention comprises:
It is obtained by adding a tetrazole compound to a polyamide resin by a known method. The method of addition is not particularly limited, and a method generally used in the field of synthetic resins may be employed. Specifically, after the polyamide resin and the tetrazole compound are dry-blended using a mixer such as a Henschel mixer, a tumbler and a ribbon blender,
A method of melt-kneading with an extruder or the like, or a method of adding a tetrazole-based compound before polymerization of the polyamide resin or during the polymerization if there is no hindrance to the polymerization reaction.

The addition amount of the tetrazole compound in the flame-retardant polyamide resin composition of the present invention is as follows.
0.1 to 50 parts by weight, preferably 100 parts by weight,
It is in the range of 0.3 to 25 parts by weight, more preferably 0.5 to 10 parts by weight. When the content of the tetrazole compound is 0.
If the amount is less than 1 part by weight, sufficient flame retardancy may not be obtained. If the amount exceeds 50 parts by weight, problems such as impairment of mechanical properties and generation of silver during molding may occur.

The molding of the flame-retardant polyamide resin obtained as described above is also carried out by a known method. For example, extrusion molding, injection molding, compression molding or blow molding can be employed. However, when performing the above-mentioned molding, it is important to carry out the molding at a molding temperature lower than the decomposition temperature of the tetrazole compound contained in the flame-retardant polyamide resin composition. This is because, when molding is performed at a temperature higher than the decomposition temperature, the tetrazole compound is decomposed during molding, and the flame retardant effect of a molded article cannot be obtained. That is, in the present invention, it is necessary that the tetrazole compound is present in the molded product without being decomposed even after the molding process.

For the above reasons, in selecting a tetrazole compound, a tetrazole compound having a decomposition temperature higher than the molding temperature of the flame-retardant polyamide resin composition, preferably higher than the molding temperature by 10 ° C., more preferably higher than 20 ° C. You need to choose. For example, the molding temperature 22
In the case of polyamide 6 resin at 0 to 230 ° C., the decomposition temperature is 240 ° C. or higher such as 5,5′-bis-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-
1H-tetrazole and the like can be used, and in particular, 5,5′-
Bis-1H-tetrazole and 5-phenyl-1H-tetrazole are preferred.

Of course, various additives or fillers commonly used in the art may be added to the flame-retardant polyamide resin composition of the present invention as long as the effects of the present invention are not impaired. For example, additives include other non-halogen-based, non-phosphorus-based flame retardants, antioxidants, ultraviolet absorbers, foaming agents, antistatic agents, coloring agents, nucleating agents, lubricants, and the like. Fiber, talc, clay and the like can be mentioned.

[0012]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

The method for evaluating flame retardancy is described below. -Flame retardancy Using a test piece with a length of 100 mm, a width of 6 mm, and a thickness of 1 mm, in accordance with JIS K7201, oxygen concentration 25% by volume
Was measured under the following conditions, and evaluated according to the following criteria.

・ ・ ・: Fire extinguished within 4 seconds of test piece ×: Test piece continued to burn for more than 4 seconds Further, the following three types of polyamide resins were used. PA-1: Polyamide 6 having a relative viscosity (measured according to JIS K6810) of 2.37 PA-2: Polyamide 6.6 PA-3 having a relative viscosity of 2.61 PA-3: Relative viscosity of 2.34 Polyamide 6.6

Examples 1 to 4 and Comparative Examples 1 to 3 After the polyamide resin and the tetrazole compound were mixed in advance by using a tumbler in the types and amounts shown in Table 1, a 30 mm coaxial biaxial kneader (Ikekai Iron Works) PCM3
0) and melt-kneaded to obtain a composition. The obtained composition was molded using an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd.) to prepare each test piece. Table 1 shows the results of the flame retardancy of each test piece.

[0016]

[Table 1]

Industrial Applicability According to the present invention, there is no occurrence of environmental pollution due to dioxin or the like during combustion, and there is no toxicity to combustion gas, and it is difficult to use it suitably in various fields such as automobile parts, home electric appliances, aircraft parts and building materials. A flame-retardant polyamide resin composition can be obtained.

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Osamu Hamazoe 3-2 Chidoricho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Denko KK Kawasaki Laboratory F-term (reference) 4H028 AA30 AA44 BA03 BA06 4J002 CL001 CL011 CL031 CL051 EU006 GL00 GN00 GQ00

Claims (4)

[Claims] 1. A flame-retardant polyamide resin composition comprising (A) a polyamide resin and (B) a tetrazole compound having a decomposition temperature not lower than the molding temperature of the polyamide resin. 2. A method according to claim 1, wherein (A) the polyamide resin comprises polyamide 6,
The flame-retardant polyamide resin composition according to claim 1, which is at least one selected from the group consisting of polyamide 6.6 and polyamide 6/6/6 copolymer. 3. The tetrazole compound having a decomposition temperature not lower than the molding temperature of the polyamide resin (B) is 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5,5'-bis-1H-tetrazole. The flame-retardant polyamide resin composition according to claim 1, which is at least one selected from the group consisting of: and a salt thereof. 4. The composition according to claim 1, wherein (A) 100 parts by weight of the polyamide resin is 0.1 to 50 parts by weight of the tetrazole compound having a decomposition temperature higher than the molding temperature of the polyamide resin. Item 6. The flame-retardant polyamide resin composition according to any one of Items 3 to 7.