JPH04154865A - Flame-retardant polyamide composition for automotive - Google Patents

Abstract

PURPOSE:To obtain a polyamide composition having excellent heat-resistant aging property and suitable for automotive components such as connector and fastener by blending a polyamide resin with a compound as a flame retardant expressed by a specific chemical structural formula at a specific ratio. CONSTITUTION:(A) 1-30wt.%, especially 2-6wt.% one or two or more kinds of compounds expressed by formula I, formula II and formula III (R1, R2 and R3 are 1-10C hydrocarbon residues) are dispersed into and blended with (B) 99-70wt.% polyamide resin (e.g. 6,6-nylon or copolymer of 6,6-nylon and 6-nylon) in a powdery state of 0.1-30mu, especially 0.1-5mu average particle diameter and <=100mu, especially <=20mu maximum particle diameter, wherein the dispersion/ blending ratio of (A) is 1-30%, esp. 2-6% per 100% of (B).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a material suitable for use as a material for automobile parts.

[Conventional technology]

Halogen-based, phosphorus-based, and nitrogen-based flame retardants are used to make polyamide flame retardant.

In the electrical and electronic fields, flame retardants have been used, each with their own advantages and disadvantages. Recently, however, there has been a movement towards flame retardancy in the automobile field, and flame-retardant polyamides have been in demand, and when we looked into suitable materials, we found that halogen-based flame retardants could cause problems with metal corrosion, so phosphorus-based flame retardants were used. However, it turned out that it had the disadvantage of being strongly colored and not being able to be colored in a variety of colors. In addition, as nitrogen-based flame retardants, melamine cyanuride-1, organic addition salts of triguanamine and cyanuric acid, and organic addition salts of diguanamino and cyanuric acid are known, but all of them are used in the automobile field. It was found that the essential heat aging resistance was poor, making it unsuitable as a material for automobile parts.

[Problem to be solved by the invention]

Thus, flame-retardant polyamide resin compositions with excellent heat aging resistance have been desired as materials for automobile parts.

[Means to solve the problem]

As a result of intensive studies to solve the above problems, the present inventors found that
The invention has been completed.

That is, the present invention uses a polyamide resin having the chemical structural formula (99 to 70% by weight) (
At least one of the compounds represented by 1), (2) and (3) 1 to 30% by weight I NO3NO3 (R is a hydrocarbon residue having 1 to 10 carbon atoms) H2NH2 (R2 is a hydrocarbon residue having 1 to 10 carbon atoms) This is a flame-retardant polyamide composition for automobile parts consisting of hydrocarbon residues.

In the present invention, polyamide is a polymer having an amide bond, and is obtained by polycondensation of an organic diamine and an organic dicarboxylic acid, polycondensation of aminocaproic acid, ring-opening polymerization of a lactam, or the like. Examples of organic diamines include tetramethylene diamine, hexamethylene diamine, metaxylylene diamine, etc.; examples of organic dicarboxylic acids include adipic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, etc.; aminocaproic acid; Examples of the lactam include ε-caproic acid and 11-aminoundecanoic acid, and lactams include ε-caprolactam and ω-laurolactam. The polyamide may be a copolymer or a polymer blend of these. Among these polyamides, 6.6-nylon, 6
．． Polyamides mainly composed of 6-nylon, copolymers of terephthalic acid, adipic acid, and hexamethylene diamine, and copolymers of terephthalic acid, hexamethylene diamine, and ε-caprolactam are particularly effective in terms of heat resistance and mechanical properties. preferable. For example, a copolymer of 6.6-nylon and 6-nylon, a blend of 6.6-nylon and 6-nylon,
Copolymers of 6T-nylon and 6-row nylon (T represents terephthalic acid), copolymers of 6T-nylon and 6-nylon, ternary copolymers of 6T-nylon, 6-row nylon, and 612-nylon, etc. Can be mentioned.

The compounds used as flame retardants are: N82NO3 (R, is a hydrocarbon residue having 1 to 10 carbon atoms) 82NH2 (R2 is a hydrocarbon residue having 1 to 10 carbon atoms) (R, is a hydrocarbon residue having 1 to 10 carbon atoms)
(a hydrocarbon residue having 1 to 10 carbon atoms).

The manufacturing method is not particularly limited, but for example, the chemical formula (1
) is synthesized by heating dicyandiamide and succinonitrile in a solvent in the presence of an alkali catalyst. A compound of chemical formula (1) can be obtained by using 21-lyl having a different number of carbon atoms in place of succinonitrile.

The compound of chemical formula (2) can be obtained, for example, by a condensation reaction of melamine and formaldehyde.

The compound of chemical formula (3) is synthesized by heating dicyandiamide and trinitrile in a solvent in the presence of an alkali catalyst.

Both compounds are white solids and are usually ground before use. The finer the particle size of the powder, the finer the particle size dispersed in the polyamide when mixed with the polyamide, which is preferable in terms of flame retardancy and mechanical properties. However, it is economically disadvantageous to make the particles finer, so particles of an appropriate particle size are used. Generally, those having an average particle size of 0.1 to 30μ are used.

The thickness is preferably 0.1 to 15μ, more preferably 0.1 to 5μ.

The blending amount of the flame retardant is 1 to 30% by weight.

If it is less than 1% by weight, flame retardancy is insufficiently expressed, and 30
If it exceeds % by weight, mechanical properties, molding fluidity, and economical efficiency will deteriorate. Preferably 1 to 10% by weight, more preferably
It is 2 to 6% by weight.

The dispersion of the flame retardant in the polyamide is preferably finely dispersed in terms of flame retardancy and mechanical properties. Even if the particle size of the flame retardant powder is made small, secondary aggregation occurs when it is blended into polyamide.

Of course, this should be avoided as much as possible, and the average particle size of the particles dispersed in the polyamide should be 0.1 to 30μ, preferably 0.1 to 20μ, more preferably 0.1 to 10μ, preferably 0. 1 to 5μ is preferable. The maximum particle size is also a problem. Preferably 100μ or less, more preferably 5
It is 0μ or less, further 20μ or less.

The method of blending the flame retardant into the polyamide is not particularly limited. When polymerizing polyamide, the method of addition is to simply mix polyamide pellets or powder and flame retardant powder.
These include a method of melt-kneading in a axial press ratio machine, a method of simply mixing polyamide pellets and flame retardant powder, and directly subjecting the mixture to injection molding.

It is preferable to further add a heat resistant agent to the composition of the present invention. Typical heat-resistant agents include copper compounds such as copper acetate, copper iodide, copper bromide, etc. 0.001-5% by weight, preferably 0.001-2% by weight, 0.1-1% by weight alkali halides. Metals such as potassium iodide, potassium bromide, etc., 0.01~
5% by weight, preferably 0.1 to 2.5% by weight, preferably used in combination with a -0- copper compound.

Hindered phenolic compounds such as N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocyanamide), 4,4'-butylidenebis(3-methyl-6-
tert-butyl-phenol), pentaerythrityl-tetrakis [3-(3,5-di-tert-butyl-
4-hydroxyphenyl)propionate] and amine compounds, such as mono-10-phosphorus compounds.

It is also preferable to add a lubricant and a mold release agent.

Calcium stearate, aluminum stearate,
Fatty acid metal salts such as calcium montanate and sodium montanate, amide compounds such as ethylene bis stearylamide and methylene bis stearyl amide, ester compounds of montanic acid and stearic acid with alcohol, etc.

The amount added is 0.01 to 0.5% by weight, preferably 0.0%
It is 5 to 0.2% by weight.

Other polyamide additives are also suitably used.

Glass fibers, potassium titanate, carphone fibers, etc. can be added as fibrous reinforcing materials, and wollastonite, kaolin, calcined kaolin, mica, talc, montmorillonite, glass peas, etc. can be added as inorganic fillers. It is usually added in an amount of 1 to 40% by weight.

The composition of the present invention is used for automobile parts.

Automotive parts, especially the inside of the engine compartment, are constantly exposed to high temperatures and are therefore required to have heat aging resistance. Furthermore, recently, high flame retardancy has been required for automobile parts, so compositions having both flame retardancy and heat aging resistance, such as the composition of the present invention, are preferably used.

Examples of automotive parts include connectors, fasteners, cable ties, junction boxes, corrugated tubes, and others.

The abbreviations of raw materials used in the examples are as follows.

・Nylon 66 (N66) Number average molecular weight 24000 ・Succinoguanamine (SG) ・Ethylene dimelamine (ED) ・Triguanamine (TG) ・Melamine cyanuride (MC) ・Ethylene dimelamine cyanurate) (EDC) 5.1 organic addition salt of ethylene dimelamine and cyanuric acid, triguanamine cyanurate (TGC) 5.1 organic addition salt of triguanamine and cyanuric acid, melamine (M) H2 Evaluation method Flame retardancy - UL94 V test According to l/321nCh
A combustion test was conducted on 10 thickness test pieces to evaluate the average burning time.

Heat aging resistance - A test piece with a thickness of 1 embryo was aged at 140°C in a hot air oven, a tensile test was performed, and the change in tensile strength retention rate over time was measured, and the time for 50% retention rate was determined as the half-life time. did.

Hinge flexibility - The test piece shown in Figure 1 was tested 60 times/
The number of times it would bend 180 degrees in minutes and break was determined.

Examples 1 to 3 94% by weight of N66 and flame retardant powder (SG, ED, TG
) 6 weight 96 and melt-kneaded using a twin-screw extruder to obtain composition pellets.

The nylon 66 used here had 0.03 copper acetate during polymerization.
% by weight, and 0.5% by weight of potassium iodide was used.

The composition pellets were injection molded to form test pieces, and heat aging resistance and flame retardance were evaluated.

Comparative Examples 1 to 4 Compositions were prepared and evaluated in the same manner as in Examples 1 to 3, except that EDC, TGCSMC, and M were used as flame retardants.

The results of Examples 1 to 3 and Comparative Examples 1 to 4 are shown in Table 1. S
It can be seen that G, ED, and TG have high heat aging resistance when compared with EDC, TGC, and MC.

From another perspective, this means that the same heat aging resistance can be achieved by adding a small amount of heat resistant agent. Adding a large amount of heat resistant agent generally causes side effects such as strong discoloration, metal corrosion, and decreased thermal stability during molding, and this also means that these side effects can be reduced.

As an example of heat aging resistance, FIG. 2 shows changes in tensile strength retention over time for the compositions of Example 1 and Comparative Example 3.

It can be seen that the blend of SG of Example 1 shows almost no decrease in strength even after 2000 hours.

In addition, for other Examples and Comparative Examples, the tensile strength half-life time was determined based on such a graph.

Table 1 Examples 4 to 10, Comparative Examples 5 to 8 N66 and SG were blended at different blending ratios and melted and kneaded using a twin-screw extruder to obtain composition pellets.

This was molded into test pieces using an injection molding machine, and flame retardancy, hinge properties, and tensile strength were evaluated.

In addition, for Example 9.10 and Comparative Example 7.8, N6
6, SG, and glass fiber (abbreviated as G and F in Table 2) were similarly blended and extruded, and after molding, flame retardancy and tensile strength were measured. The results are shown in Table 2.

It can be seen that when the SG content is less than 96% by weight, the flame retardancy becomes insufficient, and when it exceeds 30% by weight, the hinge properties and tensile strength deteriorate.

(Leaving space below) Table 2 Examples 11.12 Examples 11 and 12 show that polyamides include a copolymer of 6T-nylon and 6-row nylon (T represents terephthalic acid), 6T-nylon, 6-row nylon, and 612- The effect of SG was examined using a nylon terpolymer. As is clear from these results, good results can be obtained even when aromatic polyamide is used as the polymer.

Table 3

[Brief explanation of the drawing]

FIG. 1(A) is a plan view of the hinge flexibility test piece, and FIG. 1(B) is a front view of the hinge flexibility test piece. FIG. 2 is a graph showing heat aging resistance (temporal change in tensile strength retention (example)). Patent applicant: Asahi Kasei Industries, Ltd. Figure 1

Claims (1)

[Claims] 99 to 70% by weight of polyamide resin 1 to 30% by weight of at least one type of compound represented by chemical structural formulas (1), (2), and (3) (1) ▲ Numerical formula, chemical formula, table, etc. Yes ▼ (R_1 is a hydrocarbon residue with 1 to 10 carbon atoms) (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R_2 is
Flame-retardant polyamide composition for automobile parts consisting of (R_3 is a hydrocarbon residue having 1 to 10 carbon atoms) (3) ▲Mathematical formulas, chemical formulas, tables, etc.▼ thing.