JP2700940B2 - Polyamide resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyamide resin composition. More specifically, it has excellent heat and weather resistance, has a beautiful appearance,
Moreover, the present invention relates to a polyamide resin composition capable of providing a molded article having no change in color tone over time.

(Prior Art) Due to its excellent properties, polyamide resins are widely used in industrial materials such as tire cords, belt reinforcing materials, automobiles, electric and electronic parts, and mechanical parts. The polyamide resin material is required to have considerable heat resistance and weather resistance depending on the application. To satisfy these requirements, it is conventionally known that a copper compound is added to the polyamide resin as a heat and weather resistance auxiliary agent.

However, in the conventional method, although the heat and weather resistance is satisfied, there is a problem of coloring of the final product by the copper compound and discoloration with time, and during the production of the polyamide resin, for example, if the method is added during polymerization, The problem of copper and halide contamination and erosion of the polymerization apparatus remains. Further, a method of adding a copper compound by kneading, or a method of mechanically refining particles of the copper compound and then blending them (Japanese Patent Publication No. 56-54337)
However, there is a problem that the copper compound is agglomerated in thin molded articles such as films and sheets, fibers and the like, resulting in poor appearance and reduced physical properties.

In order to solve such a problem, the present inventors first add a heat-resistant additive containing a copper compound and, if necessary, an alkali metal halide to at least the pores of the porous polyamide powder to the polyamide resin. A method was filed (JP-A-63-291928). By this method, poor dispersion of the copper compound was eliminated, and a polyamide resin having extremely excellent heat resistance could be obtained. However, the color tone of the heat-resistant additive itself turned yellow over time, so that the color tone of the final product tended to be unstable. Was seen.

(Problems to be Solved by the Invention) The present invention has been made in view of such circumstances, and has as its object to have extremely excellent heat resistance and weather resistance and dispersibility of a copper compound, and The manufacturing process is easy,
An object of the present invention is to provide a storage-stable polyamide resin composition which does not cause coloring or discoloration of the final product over time.

(Means for Solving the Problems) The object of the present invention is to provide a powder (A) in which a copper compound is adsorbed in at least a pore portion of a porous polyamide powder, and an alkali metal or alkaline earth metal in at least a pore portion of the porous polyamide powder. This is achieved by a polyamide resin composition characterized by containing a powder (B) having a metal halide adsorbed thereon.

The porous polyamide powder of the present invention is nylon 6, nylon 66, nylon 12, nylon 11, nylon 610, nylon 4.
6, and a powder made of an aliphatic polyamide or an aromatic polyamide containing a copolymerized nylon and processed into a porous powder. In the present invention, the particle diameter of the porous polyamide powder is preferably 500 μm or less, more preferably 100 μm or less. When the particle size exceeds 500 μm, it is difficult to uniformly disperse the polyamide resin powder or pellets when dry blending is added, and the dispersibility of the copper compound tends to deteriorate. Also, the pore diameter of the porous polyamide powder,
It is preferably 20 μm or less, more preferably 5 μm or less, and most preferably 1 μm or less. When the pore size exceeds 20 μm, the surface area of the polyamide powder becomes small, so that the adsorption efficiency is deteriorated, which tends to cause a deterioration in the appearance and physical properties of the final product.

The copper compound used in the present invention is preferably a copper halide, for example, CuCl, CuI, CuCl ₂ , CuI _{2 and the} like, of which CuI is the most effective.

Further, as the alkali metal or alkaline earth metal halide used in the present invention, KBr, KI, NaCl, MgCl ₂
Among them, KI is the most effective.

A copper compound at least in the pores of the porous polyamide powder,
Alternatively, the method of adsorbing the alkali metal or alkaline earth metal halide is not particularly limited. For example, the adsorption may be performed by impregnating a porous polyamide powder with a solution of the compound and then removing the solvent. And the like. The content of the compound in the porous polyamide powder should be 0.1 to 50% by weight for uniform adsorption.
Is preferred.

Next, a powder (A) in which a copper compound is adsorbed at least in the pores of the porous polyamide powder obtained as described above, and an alkali metal or alkaline earth metal halide are adsorbed in at least the pores of the porous polyamide powder. The method of blending the powder (B) with the polyamide resin is preferably a method of dry blending with the polyamide resin and, if necessary, a method of melt-kneading.

The polyamide resin used at this time preferably has a melting point that is higher than or equal to the melting point of the porous polyamide powder to be added, and the main constituent units are preferably the same as the porous polyamide powder. This is because, when the melting point of the polyamide resin is lower than the melting point of the porous polyamide powder, the porous polyamide powder is less likely to be melted during melt molding, and poor dispersion is likely to occur, resulting in poor appearance of the molded article and deterioration of physical properties. .

The amount of the powder (A) in which the copper compound is adsorbed on at least the pores of the porous polyamide powder in the polyamide resin is 10% as the copper content of the copper compound contained in the final product.
It is preferable to mix them so as to be ~ 1000 ppm. 10ppm
If it is less than 1, the effect of improving the heat resistance is lost, and if it exceeds 1000 ppm, the heat resistance reaches saturation and the color tone of the final product tends to deteriorate.

Also, a powder (A) in which a copper compound is adsorbed in at least pores of a porous polyamide powder and a powder (B) in which a halide of an alkali metal or an alkaline earth metal is adsorbed in at least pores of a porous polyamide powder. Is preferably 0.1 to 50 times, more preferably 0.5 to 20 times the molar equivalent of the contained alkali metal or alkaline earth metal halide to the contained copper compound.

Further, a powder (A) obtained by adsorbing a powder of a mercaptan compound such as 2-mercaptobenzimidazole or 2-mercapto-2-methylbenzimidazole on at least a pore portion of a porous polyamide powder and a porous polyamide powder Together with the powder (B) in which an alkali metal or alkaline earth metal halide is adsorbed to at least the pores of the polyamide resin, preferably 0.1 to 10 times, more preferably 0.1 to 10 times the mole of the copper compound.
When added in an amount of 0.5 to 4 moles, it is possible to obtain a melt-molded product in which the color tone of the final product is extremely beautiful and has no discoloration over time. When the amount of the mercaptan compound is less than 0.1 times the molar amount of the copper compound, the effect is hardly obtained. When the amount exceeds 10 times the molar amount, the color tone of the final product tends to yellow and the appearance tends to be impaired.

Of course, the compositions of the present invention may include lubricants, plasticizers, flame retardants, fillers, reinforcing agents, colorants, and other polymers.

The polyamide composition thus obtained is melt-molded by a known method such as extrusion molding, injection molding, compression molding, and blow molding.

(Effect of the Invention) The polyamide resin composition of the present invention contains a powder in which a copper compound and a halide of an alkali metal or an alkaline earth metal are separately adsorbed to at least pores of a porous polyamide powder. Thereby, even in the dry blending method, the dispersibility is good, and a product such as a film or a fiber does not generate an agglomerate of a copper compound, and exhibits excellent appearance and heat and weather resistance. In addition, conventionally, when a copper compound was added to a polyamide resin, a change in the color tone of the final product over time could not be avoided, but the polyamide resin composition does not have such a change at all. That is, a molded article using the polyamide resin composition of the present invention has extremely excellent heat resistance and a beautiful appearance.

Further, since there is no need to add by polymerization or by kneading, there is no trouble such as contamination or corrosion of the polymerization and kneading equipment due to copper or halogen.

Further, the addition amount of the copper compound can be easily changed in accordance with the required heat and weather resistance, which makes it easy to cope with small lot production.

Further, once the copper compound and the halide of the alkali metal or alkaline earth metal are respectively adsorbed to the polyamide powder, the storage stability is good. Therefore, it is convenient to dry blend as needed.

 Hereinafter, the present invention will be described specifically with reference to examples.

(Example 1, Comparative Examples 1 and 2) Production of powder (A) in which a copper compound was adsorbed at least in pores of porous polyamide powder: 50 g of cuprous iodide was added to 1.5 of acetonitrile, and the mixture was stirred and dissolved. . Porous nylon 6 powder (average particle size 19μ, average pore size 0.24
μ) were mixed and dispersed. After stirring for several minutes, it was adsorbed and turned into a slurry. Next, acetonitrile was gradually removed, followed by vacuum drying. The amount of copper atoms in the obtained powder was determined to be 1.95% by weight.

Production of powder (B) in which alkali metal or alkaline earth metal halide is adsorbed on at least pores of porous polyamide powder: 350 g of potassium iodide and 800 m of pure water
l and stirred to dissolve. 500 g of porous nylon 6 powder (average particle diameter 19 μ, average pore diameter 0.24 μ) was mixed and dispersed therein. After stirring for several minutes, it was adsorbed and turned into a slurry. Next, after water was gradually removed, vacuum drying was performed. When potassium atom of the obtained powder was quantified, it was found to be 9.2% by weight.
Met.

Next, 51.3 g of the cuprous iodide-adsorbed nylon powder (A), 51.3 g of potassium iodide-adsorbed nylon powder (B), and 2-mercaptobenzimidazole were obtained as described above.
After mixing with 4.7 g, the mixture was dry-blended with 10 kg of nylon 6 resin and injection-molded. The molded product had a copper content of 98 ppm.

As Comparative Example 1, an additive-free product (a nylon 6 resin molded product) was added as Comparative Example 2, and cuprous iodide, potassium iodide and 2-mercaptobenzimidazole were added in the same amount as in Example 1 during polymerization. A molded article was obtained.

The appearance and mechanical properties of the obtained molded product of Example 1 were equivalent to those of the additive-free product of Comparative Example 1.

In addition, the color tone of the molded product of Example 1 and Comparative Row 2 was measured immediately after molding and after being left in a room for one month using a color difference meter (manufactured by Nippon Denshoku Co., Ltd.). The results are shown in Table 1.

From the results in Table 1, almost no difference in color tone appeared in the molded product of Example 1.

Further, when the molded articles of Example 1 and Example 2 were subjected to a weather resistance test using a sunshine weather meter, the surface crack occurrence time of the molded article of Example 1 was 1000 hours or more, and the molded article of Comparative Example 2 was obtained. Surface cracking time is 50
It was within 0 hours. Thus, the molded article of the present invention had extremely good weather resistance.

(Example 2, Comparative Example 3) Molding was performed in the same manner as in Example 1 except that nylon 6 resin was changed to nylon 66 resin.

As Comparative Example 3, an additive-free product (a nylon 66 resin molded product) was obtained.

The molded articles of Examples 1 and 2 and Comparative Examples 1 to 3 were heated in a gear oven at 150 ° C. for 168 hours, and heat resistance was evaluated based on changes in tensile strength and bending strength. The results are shown in Table 2.

As can be seen from the results in Table 2, the molded articles of the examples did not cause deterioration in physical properties and had extremely good heat resistance.

(Example 3) The nylon 6 resin composition of Example 1 was molded after being left in a room for 6 months, and the color difference from the molded product before being left was measured. As a result, the color difference ΔE was 0.8 (measured with a color difference meter (manufactured by Nippon Denshoku Co., Ltd.)).

Comparative Example 4 50 g of cuprous iodide and 350 g of potassium iodide were added to aqueous acetone 2 and dissolved by stirring. 1.25 kg of porous nylon 6 powder (average particle size: 19μ, average pore size: 0.24μ)
Mix and disperse. After stirring for several minutes, it was adsorbed and turned into a slurry. Next, the acetone was gradually removed, followed by vacuum drying. The amount of copper atoms in this powder was determined to be 1.00% by weight. Next, 1.0% by weight of this powder, 0.047% by weight of 2-mercaptobenzimidazole, nylon 6
The resin was dry-blended and molded after standing for 6 months in a room, and the color difference from the molded product before leaving was measured.
As a result, the color difference ΔE = 2.8 (color difference meter (manufactured by Nippon Denshoku Co., Ltd.)
) And the color tone changed, indicating that the storage stability was poor. In addition, the copper content of this resin was 98 ppm.

Claims (1)

(57) [Claims] A powder in which a copper compound is adsorbed on at least pores of a porous polyamide powder, and a powder in which an alkali metal or alkaline earth metal halide is adsorbed on at least pores of the porous polyamide powder. (B). A polyamide resin composition comprising: