JPH04236262A - Polyamide composition - Google Patents

Abstract

PURPOSE:To obtain a polyamide composition keeping excellent flexibility, heat- resistance, weather resistance and discoloration-preventing property over a long period by compounding a plasticized polyamide with a copper halide compound, a potassium halide and a polycarbonate oligomer. CONSTITUTION:The objective polyamide composition is produced by compounding (A) 100 pts.wt. of a plasticized polyamide produced by compounding 5-25wt.% of a low-molecular weight plasticizer (preferably p- toluenesulfonamide, etc.) to nylon 11 or nylon 12 with (B) 0.005-0.1 pts.wt. (in terms of Cu) of a copper halide compound, preferably a complex of a copper halide and 2-mercaptobenzimidazole or 2-mercaptobenzothiazole, (C) 0.05-1 pt.wt. (preferably 0.1-0.5 pts.wt.) of a potassium halide (preferably potassium iodide) and (D) 0.1-10 pts.wt. (preferably 0.5-5 pts.wt.) of a polycarbonate oligomer, preferably an oligomer produced by the reaction of bisphenol A and phosgene and containing 2-20 (preferably 5-10) recurring units of formula.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polyamide compositions that provide the long-term flexibility, heat resistance, weather resistance and color resistance of plasticized polyamides. More specifically, the present invention is applicable to fields that require environmental resistance properties such as heat resistance and weather resistance without loss of flexibility over a long period of time, and coloration prevention properties with little color change over time, such as tubes, hoses, sheets, etc. The present invention relates to a polyamide composition suitable as a molded article for industrial products.

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.

Furthermore, due to the structure of the polymer, polyamides become colored due to thermal history, and even those that have been given heat resistance and weather resistance by applying a stabilizing formulation also suffer from significant color change over time. This is because changes in the stabilizer consumed for heat resistance and weather resistance are the cause of coloration.

Furthermore, the degree of coloration due to the addition of stabilizers, changes in stabilizers (decomposition products) consumed for heat resistance and weather resistance, and coloration caused by polymer decomposition products tends to increase with time. becomes. By adding a large amount of stabilizer, it is possible to lengthen the introduction period until the polymer begins to decompose and delay the onset of coloration, but increasing the amount of stabilizer added will lower the physical properties of the polymer. There is a problem.

[0016] Accordingly, it is an object of the present invention to provide a polyamide composition that can be used for a long period of time without impairing flexibility, has excellent heat resistance and weather resistance, and has improved anti-coloring properties without impairing the physical properties of the polymer.

[0017]

[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 made by blending nylon 12 with 5-25% by weight of a low molecular weight plasticizer, (B) 0.005-0.1 parts by weight of a copper halide compound in terms of copper atomic weight, (C) halogen A polyamide composition comprising 0.05 to 1 part by weight of potassium chloride and 0.1 to 10 parts by weight of (D) a polycarbonate oligomer, and the copper halide compound (B) containing copper halide, 2-mercaptobenzimidazole, and The above polyamide composition is a complex with a compound selected from 2-mercaptobenzthiazole.

In the present invention, it is important to blend all of the copper halide, potassium halide, and polycarbonate oligomer into the plasticized polyamide.
The effect becomes even more pronounced by using copper halide as a complex with a specific compound. Furthermore, by incorporating polycarbonate oligomer, the coloring prevention properties are significantly improved.

[0020] In the present invention, by adopting the above configuration, volatilization of the plasticizer and stabilizer and coloring change over time are suppressed, and good flexibility, heat resistance, weather resistance, and coloring prevention properties are maintained over a long period of time. It will be maintained.

The present invention will be explained in detail below.

In the present invention, (A) plasticized polyamide is 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.

Examples of the low molecular weight plasticizer 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.

[0026] 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.

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, based on 100 parts by weight of the plasticized polyamide.

If the amount of potassium halide added is less than 0.05 part by weight, the heat resistance and weather resistance of the polyamide composition obtained will decrease, and even if the amount added exceeds 1.0 part 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.

The polycarbonate oligomer (D) in the present invention has the following repeating unit.

[0033]

[Chemical formula 1]

Each R is independently selected from aromatic groups such as naphthylene, phenylene, halogen-substituted phenylene and alkyl-substituted phenylene, and X and Y each have hydrogen or an aliphatic unsaturated bond. selected from the group consisting of free hydrocarbon groups and groups that together with adjacent carbon atoms form a cycloalkane group. However, the total number of carbon atoms in X and Y is 12 or less.

Preferred polycarbonate oligomers include those derived from the reaction of bisphenol A and phosgene and having the following repeating units, usually 2 to 2
Those having 0, preferably 5 to 10 repeating units are used.

[0036]

[Case 2]

The amount of polycarbonate oligomer added is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the plasticized polyamide.

Although the method for producing the polyamide composition of the present invention is not particularly limited, copper halide compound (B
), potassium halide (C) and polycarbonate oligomer (D) are preferably dry blended 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.

[0040]

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.

[0041] Each physical property in the examples was determined as follows.

[0042] Heat resistance: The polyamide composition was formed into a sheet with a thickness of 2 mm by hot pressing, and the JIS K6301
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.

[0043] 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, the temperature was 120°C in a hot air oven.
After 500 hours of treatment, the weight loss was measured and the ratio to the amount of plasticizer added was calculated.

Polymer color tone: A polyamide composition was formed into a sheet with a thickness of 2 mm by hot pressing, and the sheet was cut into a size of 5 cm x 5 cm to be used as a test piece.

[0046] This test piece was treated at a predetermined temperature and time, and the polymer color tone based on surface reflection was measured using an SM color computer (manufactured by Suga Test Instruments).

L value: Brightness of the surface, YI value: Indicates the yellowness of the surface. The larger the value, the brighter the L value, and the YI value.
The value indicates a strong yellow tinge.

Examples 1-2, Comparative Examples 1-10 Thermoplastic polyamide (trade name "Rilsan" BESNO ATO
Chem. made of nylon 11) or plasticized polyamide (trade name “Rilsan”) BESNO P40 ATO
Chem. Made of plasticized nylon-11, plasticizer approx. 14
"Irganox" 10 as a hindered phenol stabilizer in the pellets (wt% content)
98, “Naugard” as an aromatic amine stabilizer
(Naugard)" 445, as a hindered amine stabilizer "Tinuvin" 326, as a copper stabilizer copper iodide or "OS-13" (equimolar complex of copper iodide and 2-mercaptobenzimidazole) , potassium iodide and polycarbonate oligomer (trade name "Iupilon" AL-07 as a coloring inhibitor)
1, manufactured by Mitsubishi Gas Chemical Co., Ltd.) were dry blended at the ratios shown in Table 1 immediately before extrusion, and 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.

[0049] This pellet was 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.

[0051]

[Table 1]

Examples 3-4, Comparative Examples 11-15 Example 1
~2, A weather resistance test was conducted using the 2 mm thick press sheets prepared in Comparative Examples 6 to 10. The results are shown in Table 2.

[0053]

[Table 2]

Examples 5-6, Comparative Examples 16-20 Example 1
~2, The plasticizer weight loss rate was measured using the 2 mm thick press sheets prepared in Comparative Examples 6 to 10. 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.

[0055]

[Table 3]

Examples 7-8, Comparative Examples 21-22 Example 1
~2, Among the 2 mm thick press sheets produced in Comparative Examples 6 to 10, copper halide stabilization formulations with low heat resistance, weather resistance, and plasticizer weight loss rate (Examples 1 to 2, Comparative Example 9
~10) Cut into a size of 5cm x 5cm,
Changes in polymer color tone over time at each temperature were measured.

The results are shown in Table 4.

[0058]

[Table 4]

From the results in Table 1, it can be seen that for ordinary polyamides, whether a hindered phenol stabilizer, an aromatic amine stabilizer, a hindered amine stabilizer, or a copper halide-potassium halide stabilizer is used. However, in plasticized polyamide, copper halide-potassium halide stabilizers (Comparative Examples 9-10, Examples 1-2)
) is found to have very good heat resistance.

In addition, the results in Table 2 show that the weather resistance of the copper halide stabilizer is very good, and that the weather resistance is slightly improved by adding polycarbonate oligomer. The results show that when a copper halide stabilizer is used, the plasticizer weight loss rate is extremely low, and the 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.

However, from the results shown in Table 4, unless a polycarbonate oligomer is blended in addition to a copper halide stabilizer, the color tone of the polymer is significantly reduced. Even at a high temperature of ~140°C for a long period of time, there is only a slight decrease in brightness and yellowing is also small, indicating that it has an excellent coloring prevention effect.

Therefore, from the results in Tables 1 to 4, only when all of the copper halide compound, potassium halide, and polycarbonate oligomer are blended into the plasticized polyamide, volatilization of the plasticizer is suppressed and long-term heat resistance is achieved. ,
It can be seen that it maintains weather resistance and flexibility, and also prevents coloring of the polymer.

[0063]

EFFECTS OF THE INVENTION The polyamide composition of the present invention has excellent heat resistance, weather resistance, and anti-coloration properties over a long period of time without loss of flexibility.

The polyamide composition of the present invention is particularly useful for hoses, tubes, sheets, and other fields that require long-term flexibility and excellent heat resistance, weather resistance, and anti-staining properties. It can be suitably used for industrial parts.

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;
5 to 0.1 parts by weight, (C) potassium halide 0.05 to 1 part by weight, and (
D) A polyamide composition containing 0.1 to 10 parts by weight of a polycarbonate oligomer. 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.