JPH04222860A - Polyamide composition - Google Patents

Abstract

PURPOSE:To obtain a polyamide composition excellent in heat resistance and weather resistance without damaging flexibility for a long period of time by blending a plasticized polyamide with a halogenated copper compound and a potassium halide. CONSTITUTION:(A) 100 pts.wt. plasticized polyamide obtained by blending nylon 11 or nylon 12 with 5-25wt.% low-molecular weight plasticizer (preferably N- butylbenzenesulfonamide or p-toluenesulfonamide) is mixed with (B) 0.005-0.1 pt.wt. calculated as copper atom of a halogenated copper compound, preferably complex of a copper halide and a compound selected from 2- mercaptobenzimidazole and 2-mercaptobenzthiazole, especially cuprous chloride and an equimolar amount of 2-mercaptobenzimidazole and (C) 0.05-1 pt. wt., preferably 0.1-0.5 pt.wt. potassium halide (preferably potassium iodide) preferably by dry blending of the component A before molding with the component B and the component C to give a polyamide composition.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide composition that provides long-term flexibility, heat resistance, and weather resistance to plasticized polyamides. More specifically, the present invention includes:
The present invention relates to a polyamide composition suitable for use in fields where environmental resistance properties such as heat resistance and weather resistance are required without loss of flexibility over a long period of time, such as molded articles for industrial products such as tubes, hoses, and sheets.

0002

BACKGROUND OF THE INVENTION Plasticized polyamides are generally produced by kneading low molecular weight monomers with polyamides (non-plasticized polyamides), and the amount of plasticizer is kneaded depending on the degree of flexibility.

[0003] These plasticized polyamides have almost no problems when used in a normal atmosphere, but for example 10
When exposed to an atmosphere at a temperature of 0° C. or higher, the plasticizer evaporates from the plasticized polyamide, and the plasticizer content decreases over time.

That is, if the heated state is continued, the original flexibility of the plasticized polyamide is lost as the plasticizer content decreases, which poses a problem in terms of long-term use.

[0005] Therefore, in order to maintain these long-term flexibility, plasticizers that do not volatilize from the plasticized polyamide have been investigated, and high molecular weight type plasticizers have been proposed as such plasticizers.

However, commonly used plasticizers include those whose purpose is to impart flexibility rather than to inhibit volatilization.
Specifically, low molecular weight liquid monomers that have a large plasticizing effect are generally used.

On the other hand, as a stabilizing formulation for polyamide,
It is known to blend cuprous iodide and an alkali metal iodide (Japanese Patent Publication No. 14630/1983).

[0008]

However, in the field of plasticized polyamides, it is still almost impossible to maintain the flexibility of plasticized polyamides containing low molecular weight plasticizers over a long period of time.

On the other hand, polyamide is inferior in environmental resistance properties such as heat resistance and weather resistance, and plasticized polyamide with flexibility is similarly inferior in environmental resistance properties.

[0010] However, at present, stabilizing formulations for heat resistance, weather resistance, etc. for plasticized polyamides have hardly been studied, and stabilizing formulations for polyamides that are commonly used are simply applied. There are also the following problems.

As stabilizing formulations for plasticized polyamides, the following polyamide stabilizers and weathering agents are widely used. For example, to improve heat resistance, hindered phenol stabilizers, aromatic amine stabilizers, and
Hindered amine stabilizers are available to improve weather resistance. Furthermore, in order to improve heat resistance and weather resistance, formulations include a combination of an aromatic amine stabilizer and a hindered amine stabilizer.

However, when these stabilizing formulations are applied to plasticized polyamide, due to the problem of compatibility between the stabilizer, plasticizer, and polyamide, the stability is different from when the stabilizer and plasticizer are individually blended into polyamide. behavior.

[0013] In other words, the above-mentioned hindered phenol stabilizers and aromatic amine stabilizers have better compatibility with plasticizers than with polyamides, so
As the plasticizer volatilizes, there is a problem that the stabilizer also volatilizes, and when used for a long period of time, flexibility, heat resistance, and weather resistance are impaired.

[0014] Therefore, the object of the present invention is to provide a polyamide composition that does not lose flexibility and has excellent heat resistance and weather resistance over a long period of time.

[0015]

[Means for Solving the Problems] The present inventors have made extensive studies to solve the above problems, and as a result, have arrived at the present invention.

That is, the present invention provides (A) nylon 11
or 100 parts by weight of a plasticized polyamide containing 5 to 25% by weight of a low molecular weight plasticizer in nylon 12, (B) 0.005 to 0.1 parts by weight of a copper halide compound in terms of copper atomic weight, and (C) halogen. A polyamide composition containing 0.05 to 1 part by weight of potassium chloride, and the copper halide compound (B) is a complex of copper halide and a compound selected from 2-mercaptobenzimidazole and 2-mercaptobenzthiazole. The above polyamide composition is

In the present invention, it is important to use copper halide in combination with potassium halide, and the effect becomes even more pronounced by using copper halide as a complex with a specific compound. be.

In the present invention, by employing the above structure, volatilization of the plasticizer and stabilizer is suppressed, and good flexibility, heat resistance, and weather resistance are maintained over a long period of time.

The present invention will be explained in detail below.

(A) Plasticized polyamide in the present invention refers to nylon 1 obtained from 11-aminoundecanoic acid.
Nylon 12 obtained from 1 or 12-aminododecanoic acid or laurolactam with a low molecular weight plasticizer 5~
It contains 25% by weight.

The low molecular weight plasticizers include p-oxybenzoic acid esters, aromatic oxycarboxylic acid ethers, phenols, aromatic oxyaldehydes, polyhydric phenol phosphoric esters, N-alkylbenzenesulfonamides, Examples include N-alkyl-p-toluenesulfonamides and p-toluenesulfonamide. Among them, N-butylbenzenesulfonamide, which is an N-alkylbenzenesulfonamide, and N-ethyl-p-toluenesulfonamide and p-toluenesulfonamide, which are N-alkyl-p-toluenesulfonamides, are preferably used.

Examples of the copper halide compound (B) in the present invention include cuprous (second) iodide, cuprous (second) chloride, cuprous (second) acetate, etc. Preferably, cuprous iodide is used.

In the present invention, when the above copper halide compound is used as a complex of copper halide and a compound selected from 2-mercaptobenzimidazole and 2-mercaptobenzthiazole, the effects of the present invention can be further enhanced. can be improved. In the above complex, the compound reacted with copper halide is 2-mercaptobenzimidazole or 2-mercaptobenzimidazole, with 2-mercaptobenzimidazole being preferred.

[0024] Further, the above-mentioned complex is usually combined with a copper halide.
It is a complex with a compound selected from 2-mercaptobenzimidazole and 2-mercaptobenzthiazole in a 1 to 2 times molar amount, preferably an equimolar amount.

In the present invention, a complex salt of cuprous iodide and equimolar amount of 2-mercaptobenzimidazole is most preferably used.

[0026] The amount of copper halide added is 0.005 to 100 parts by weight in terms of copper atoms per 100 parts by weight of the plasticized polyamide.
It is 0.1 part by weight. If the amount added is less than 0.005 parts by weight, the heat resistance of the resulting composition will not be sufficient;
Even if the amount exceeds 1 part by weight, the heat resistance and weather resistance of the resulting composition will not change significantly, making it uneconomical.

Examples of the potassium halide (C) in the present invention include potassium chloride and potassium iodide, among which potassium iodide is preferably used.

The amount of potassium halide added is 0.05 to 1.0 parts by weight, preferably 0.1 to 0.5 parts by weight, per 100 parts by weight of the plasticized polyamide.

If the amount of potassium halide added is less than 0.05 parts by weight, the heat resistance and weather resistance of the polyamide composition obtained will decrease, and even if the amount added exceeds 1.0 parts by weight, the polyamide composition obtained will deteriorate. The heat resistance and weather resistance of the composition do not change significantly, and it is not economical.

Although the method for producing the polyamide composition of the present invention is not particularly limited, it is preferable to dry blend copper halide (B) and potassium halide (C) with the plasticized polyamide before molding.

The polyamide composition of the present invention can be generally formed into various molded articles by known molding methods.

[0032]

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited by these Examples.

[0033] Each physical property in the examples was determined as follows.

[0034] Heat resistance: The polyamide composition is hot-pressed into a sheet with a thickness of 2 mm, and the polyamide composition is formed into a sheet with a thickness of 2 mm,
A dumbbell test piece conforming to the above was punched out, and this test piece was treated in a hot air oven at a predetermined temperature and time, and its tensile strength and elongation were measured using a tensile tester "Tensilon" 100 (manufactured by Shimadzu Corporation). Then, the tensile elongation after heat treatment with respect to the tensile elongation measured before heat treatment was calculated as the tensile elongation retention rate [Tensile elongation retention rate = (Tensile elongation after heat treatment / Tensile elongation before heat treatment) × 100 (%)]. As a guideline for heat resistance, a tensile elongation retention rate of 50% was defined as the half-life at that temperature.

[0035] Weather resistance: Using the same test piece as used when measuring heat resistance, it was tested with a Weather-O-meter (manufactured by Suga Test Instruments) for 200 and 500 hours (both at 63°C,
The tensile strength and elongation of the material was measured using "Tensilon" 100 after irradiating it with light from a carbon arc (sprayed with water for 18 minutes within 2 hours). Then, as in the case of heat resistance, the tensile elongation after the weather resistance test relative to the tensile elongation measured before the weather resistance test was calculated as the tensile elongation retention rate. The half-life of the weather resistance was set at 50% retention of tensile elongation.

Plasticizer weight loss rate: Using the same test piece as when measuring heat resistance,
After 500 hours of treatment, the weight loss was measured and the ratio to the amount of plasticizer added was calculated.

Examples 1-2, Comparative Examples 1-8 Thermoplastic polyamide (trade name "Rilsan" BESNO ATO C
hem. made of nylon 11) or plasticized polyamide (trade name “Rilsan”) BESNO P40 ATO
Chem. ``Irganox'' 109 as a hindered phenol stabilizer to the pellets (made of plasticized nylon-11, containing approximately 14% by weight of plasticizer)
8. ``Naugard'' as an aromatic amine stabilizer
Naugard)” 445, as a hindered amine stabilizer “Tinuvin” 326, copper iodide, potassium iodide and “OS-13” (equimolar complex of copper iodide and 2-mercaptobenzimidazole)
were dry blended in the proportions listed in Table 1 immediately before extrusion,
The mixture was kneaded at 250° C. using a 30 mmφ extruder (Dulmage screw, manufactured by Tanabe Seisakusho). The gut was cooled in a water bath and passed through a cutter to pelletize it.

[0038] The pellets were heated in a hot air oven at 70°C for 1
It was dried for 5 hours. The dried pellets were melted using a hot press to produce a 2 mm thick press sheet. A heat resistance aging test was conducted at three levels: 120°C, 140°C, and 150°C.

Table 1 shows the results of heat aging resistance.

[0040]

[Table 1]

From the results in Table 1, the following is clear.

That is, in ordinary polyamide,
There is no noticeable difference in heat resistance effects using any of the hindered phenol stabilizers, aromatic amine stabilizers, hindered amine stabilizers, and copper halide-potassium halide stabilizers. However, in plasticized polyamides, the heat resistance is very good only when a copper halide-potassium halide stabilizer is used.

Examples 3 to 4 and Comparative Examples 9 to 11 Using the 2 mm thick press sheets prepared in Example 1, a weather resistance test was conducted. The results are shown in Table 2.

[0044]

[Table 2]

From the results in Table 2, it is clear that the copper halide stabilizer has very good weather resistance.

Examples 5-6, Comparative Examples 12-14 Example 1
The plasticizer weight loss rate was measured using a 2 mm thick press sheet prepared in . Further, the flexural modulus of elasticity was measured using the dumbbells that had been weighed at this time. Table 3 shows the results of the plasticizer weight loss rate and flexural modulus at that time.

[0047]

[Table 3]

From the results in Table 3, it can be seen that when a copper halide stabilizer is used, the weight loss rate of the plasticizer is extremely low, and volatilization of the plasticizer is suppressed. Furthermore, it is clear that when a copper halide stabilizer is used, the flexural modulus increases little due to heat treatment and flexibility is maintained.

[0049]

Effects of the Invention The polyamide composition of the present invention has excellent heat resistance and weather resistance without losing its flexibility over a long period of time.

The polyamide composition of the present invention is particularly suitable for use in hoses, tubes, sheets, and other industrial parts that are required to maintain flexibility over a long period of time and have excellent heat resistance and weather resistance. It can be suitably used for.

Claims (2)

[Claims] Claim 1: (A) 100 parts by weight of a plasticized polyamide prepared by blending 5 to 25% by weight of a low molecular weight plasticizer with nylon 11 or nylon 12; (B) 0.00 parts by weight of a copper halide compound in terms of copper atomic weight;
A polyamide composition containing 5 to 0.1 parts by weight and (C) 0.05 to 1 part by weight of potassium halide. 2. The polyamide composition according to claim 1, wherein the copper halide compound (B) is a complex of copper halide and a compound selected from 2-mercaptobenzimidazole and 2-mercaptobenzthiazole.