JPH047359A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To obtain the title repeatedly reclaimable good composition continuously, easily and inexpensively by melt-kneading a polyamide with a graft polymer containing an unsaturated carboxylic acid (anhydride) as a monomer unit. CONSTITUTION:100 pts.wt. polyamide is melt-kneaded with 0.1-1 pt.wt., desirably 0.3-1 pt.wt. graft polymer containing an unsaturated carboxylic acid (anhydride) as a monomer unit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyamide resin composition that is widely used as an engineering plastic.

(Prior Art) In recent years, polyamide resins have been widely used in many fields as engineering plastics with excellent toughness, self-lubricating properties, wear resistance, chemical resistance, self-extinguishing properties, gas barrier properties, etc.

(Problem to be solved by the invention) However, when polyamide is processed at temperatures above its melting point, such as extrusion processing and injection molding, thermal decomposition occurs within the cylinder of the processing machine, and as the thermal history increases, the molecular weight and mechanical A decrease in strength was unavoidable, which was an obstacle to reusing it as a molding resin.

In view of these drawbacks, the present invention aims to produce a high-quality product that can be easily, inexpensively, and repeatedly regenerated in a continuous process by blending polyamide with a graft polymer having a functional group that reacts with the polyamide. The object of the present invention is to provide a polyamide resin composition.

(Means for solving problems) The present invention will be explained in detail below.

The molecular structure of the graft polymer in the present invention includes a monomer unit derived from an unsaturated carboxylic acid or its anhydride as a trunk component, and has arbitrary polymer segments as branch components.

Examples of the unsaturated carboxylic acid or anhydride thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid, and unsaturated carboxylic acid anhydrides such as maleic anhydride. Among these, unsaturated carboxylic acid anhydrides are preferred from the viewpoint of reactivity with the terminal amino groups of polyamide, and maleic anhydride is particularly preferred.

The polyamide resin composition of the present invention is a resin composition consisting of polyamide and a graft polymer, and the blending ratio thereof is preferably 0.1 to 1 part by weight, and 0.1 to 1 part by weight of the graft polymer to 100 parts by weight of the polyamide. 3 to 1 part by weight is more preferred.

If the proportion of the graft polymer is less than 0.1 part by weight, the effect of the graft polymer will be insufficient, which is not preferable, and if the proportion of the graft polymer exceeds 1 part by weight, the melt viscosity during kneading will increase too much. This is not preferable because it may cause a decrease in moldability or a decrease in the physical properties of the final molded product.

The polyamide resin composition of the present invention may be obtained by melt-kneading both the polyamide and the graft polymer using a conventional blending method, such as an extruder or kneader. A preferred method is to mix the mixture using various types of mixers, heat and melt the mixture using an extruder, extrude the mixture, and cut the mixture into pellets.

(Example) Embodiments of the present invention will be described in detail below.

In addition, the parts written on each side mean parts by weight.

Examples 1 to 6 The ratio of graft polymer listed in Tables 1 to 4 (0.05 parts to 1.5 parts) to 100 parts of commercially available polyamide resin (manufactured by Takayasu ■, trade name Tanazine 6 Nylon TN 100)
and melt blended using a single screw extruder at a cylinder temperature of 230°C.

This blend was thoroughly dried, melt-blended again using a single-screw extruder, and this operation was repeated one more time to produce recycled products a total of three times.

First, the relative viscosity of the products recycled 1 to 3 times was measured using an Ostwald viscometer, and then test pieces were made using an injection molding machine and subjected to a tensile test, a bending test, and an Izot impact test. did.

However, the relative viscosity is determined by JIS K-6810, and the tensile test, bending test, and Izot impact test are determined by A.
It was conducted according to STM D-638, D-790, and D-256.

Examples 7 to 12 Commercially available polyamide resin (manufactured by Takayasu, trade name Tanajin 66)
The graft polymer was added to 100 parts of nylon TN710) in the proportions listed in Tables 5 to 8 (0.05 parts to 1.5 parts), and melted at a cylinder temperature of 270 °C using a single screw extruder. Blended.

This blend was thoroughly dried, melt-blended again using a single-screw extruder, and this operation was repeated one more time to produce recycled products a total of three times.

First, the relative viscosity of the products recycled 1 to 3 times was measured using an Ostwald viscometer, and then test pieces were made using an injection molding machine and subjected to a tensile test, a bending test, and an Izot impact test. did.

In addition, the test method was based on Examples 1-6.

Comparative Example 1.2 Examples 1 to 6 except that no graft polymer was added
And it carried out similarly to Examples 7-12.

The test results of the polyamide resin compositions on each side are summarized in Tables 1 to 8.

However, the original values in the table indicate the values measured before extrusion of the polyamide resin used this time.

(Leaving space below) Table 2 Tensile strength (kg/cn) [Original: 620] Table 1 Relative viscosity [Original: 2°7] Table 3 Tensile elongation at break (%) [Original: 150] Table 4 Izod impact strength (kg ° cu+/cm) (Original: 9゜3) Table 6 Tensile strength (kg/cd) [Original near 80] Table 5 Relative viscosity [Original: 2゜8] Table 7 Tensile elongation at break (%) [Original: 40] Table 8 Izod impact strength (kg-CIIl/Cl11) [Original: 4.0.1 The following is clear from the examples and comparative examples.

Polyamide resin is a representative engineering plastic that has both high rigidity and high toughness, but as shown in the comparative examples in Tables 1 to 8, when extrusion processing is continued repeatedly, the viscosity clearly decreases due to thermal decomposition reaction. However, by adding a graft polymer as in the example, within the scope of the present invention, almost no viscosity decrease is observed, and in fact, the viscosity can even be improved. .

In addition, in the tensile tests shown in Tables 2.3 and 6.7, which serve as a guideline for stiffness, in the comparative examples there was a noticeable decrease in strength and rapid decrease in elongation at break, whereas in the scope of the present invention, no decrease was observed at all. I couldn't.

Furthermore, in terms of Izod impact strength shown in Tables 4 and 8, high physical properties can be maintained even after repeated regeneration as many as three times, similar to the relative viscosity and tensile tests.

Therefore, the present invention can prevent a decrease in viscosity by adding a small amount of a graft polymer having a specific structure that can easily react to a polyamide resin, and also improve rigidity and
It is possible to obtain a resin composition that is highly valued in terms of both toughness.

(Effect of the invention) The polyamide resin composition according to the present invention is obtained by melt-kneading polyamide and a graft polymer containing an unsaturated carboxylic acid or its anhydride as a monomer unit, and is made by melt-kneading polyamide and a graft polymer containing an unsaturated carboxylic acid or its anhydride as a monomer unit, and is made by melt-kneading polyamide and a graft polymer containing an unsaturated carboxylic acid or its anhydride as a monomer unit. Since the graft polymer is contained in an amount of 0.1 to 1 part by weight, it is possible to prevent a decrease in toughness and improve impact strength when repeatedly regenerating a polyamide resin at a low cost, easily, and continuously. It is very useful industrially.

Claims (1)

[Scope of Claims] Polyamide and a graft polymer containing an unsaturated carboxylic acid or its anhydride as a monomer unit are melt-kneaded, and the amount of the graft polymer is 0.1 to 1 weight per 100 parts by weight of the polyamide. 1. A polyamide-based resin composition characterized in that: