JPH0841319A - Polyamide resin composition - Google Patents

Abstract

PURPOSE:To obtain a polyamide resin composition excellent in toughness by mixing a specified crystalline terpolyamide with a modified polyolefin obtained by grafting an alpha,beta-unsaturated carboxylic acid onto a polyolefin. CONSTITUTION:This composition comprises 65-95wt.% crystalline terpolyamide comprising an equimolar salt of hexamethylenediamine with adipic acid, an equimolar salt of hexamethylenediamine with terephthalic acid and a monomer forming nylon 11 or nylon 12 and 5-35wt.% modified polyolefin obtained by grafting 0.05-5mol% alpha,beta-unsaturated carboxylic acid, its anhydride or its derivative onto a polyolefin. Examples of the monomers forming nylon 11 include omega-undecanolactam and 11-aminoundecanoic acid, and examples of the monomers forming nylon 12 include omega-laurolactam and 12-aminododecanoic acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel polyamide resin composition. More specifically, the present invention relates to a polyamide resin composition having excellent toughness.

Polyamide resins have excellent heat resistance, oil resistance, moldability, rigidity, toughness, etc., and therefore, electric power tools, general industrial parts, mechanical parts, electronic parts, automobile interior and exterior parts, It is being developed into various functional parts such as engine room parts and automobile electrical parts.

However, since the aliphatic polyamide has a high water absorption rate, there has been a problem that a molded article formed of such an aliphatic polyamide has a large variation in size and physical properties due to absorption of water.

Aromatic polyamides are known as polyamides in addition to the aliphatic polyamides described above. This aromatic polyamide uses dicarboxylic acid,
It is a polyamide obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic diamine.

Since the aromatic polyamide has a low water absorption rate unlike the aliphatic polyamide, the use of the aromatic polyamide reduces the dimensional accuracy due to the absorption of water by the molded article as described above, and Problems such as changes in physical properties are solved. In addition, since this aromatic polyamide generally has a higher melting point than the aliphatic polyamide, it has an advantage of excellent heat resistance.

However, a detailed examination of a molded article molded from an aromatic polyamide has a problem that it has lower toughness such as elongation and impact resistance than a molded article molded from an aliphatic polyamide.

[0007]

Description of the Prior Art Under these circumstances, various improvements have been attempted for aromatic polyamides. For example, JP-A-3-285951, JP-A-4-198264, JP-A-5-43768, and JP-A-5-117.
525, JP-A-58-120665, JP-A-1-98665, JP-A-2-240162, and the like. Although these binary crystalline aromatic polyamides have high heat resistance and have a certain degree of toughness, they cannot be said to be sufficient when used for the above applications.

[0008]

DISCLOSURE OF THE INVENTION The present invention is a molding which does not impair the heat resistance and low water absorption of an aromatic polyamide, and which has excellent toughness which is not sufficient with a conventional binary crystalline aromatic polyamide. An object of the present invention is to provide an aromatic polyamide resin composition from which a product can be obtained.

That is, according to the present invention, (a) an equimolar salt of hexamethylenediamine and adipic acid, (b) an equimolar salt of hexamethylenediamine and terephthalic acid, and (c) nylon 11 or nylon 12 forming property. Crystalline terpolymerized polyamide (A) 65 consisting of monomers
Modified polyolefin (B) 5 obtained by graft-polymerizing 95% by weight of polyolefin with 0.05 to 5 mol% of α, β-unsaturated carboxylic acid, its anhydride or its derivative.
To 35 wt% of the polyamide resin composition.

[0010]

Next, the polyamide resin composition of the present invention will be specifically described. (A) Hexamethylenediamine and the equimolar salt of adipic acid, which are the constituents of the crystalline terpolymer polyamide (A) used in the present invention, have a pH of 7.1 in an aqueous solution of 80 ° C. In the polymerization of this equimolar salt,
Hexamethylenediamine may be added in an excess amount of about 1 mol% with respect to the number of moles of the charged salt in consideration of the amount of diamine entrained and distilled during the distillation of water from the polymerization system. It is preferable that the molar ratio of hexamethylenediamine and adipic acid has a slight range for the purpose of adjusting the terminal group concentration of the polymer.

Similarly, (b) the equimolar salt of hexamethylenediamine and terephthalic acid is a synthetic salt whose pH is adjusted to 6.9 in an aqueous solution of 80 ° C. is called an equimolar salt.
For the same reason as above, it is rather preferable that the molar ratio of hexamethylenediamine and terephthalic acid has a certain range in order to adjust the molecular weight to a predetermined value.

Further, (c) nylon 11-forming monomers include ω-undecalactam and 11-aminoundecanoic acid, and nylon 12-forming monomers include ω-laurolactam and 12-aminododecanoic acid. To be

There are no particular restrictions on the production conditions for the crystalline terpolymerized polyamide used in the present invention.
The polymer can be obtained by appropriately combining atmospheric pressure, pressurization and depressurization at a temperature of ° C. Specifically, a predetermined amount of the raw material monomer is charged into a pressure-stirring polymerization tank, the temperature is raised to a predetermined temperature to obtain a prepolymer having a molecular weight of 1500 to 3000, and then the melting point of the prepolymer is obtained using an extruder. The post-polymerization can be performed at a polymerization temperature set higher by about 20 ° C., but is not limited to this method.

The constituent component of the modified polyolefin (B) used in the present invention is a poly-α-olefin modified with α, β-unsaturated carboxylic acid, its anhydride or its derivative, which will be described later. It is obtained by modifying a polymer obtained by polymerizing at least one monomer selected from α-olefins.

As the α, β-unsaturated carboxylic acid, its anhydride or its derivative used here, monobasic carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and isocrotonic acid, maleic acid, fumaric acid, Dibasic carboxylic acids such as itaconic acid and citraconic acid, and their anhydrides or salts. Acrylic acid, methacrylic acid, maleic anhydride, itaconic anhydride and zinc salts or sodium salts thereof are preferable, and maleic anhydride and itaconic anhydride are particularly preferable.

The content of the α, β-unsaturated carboxylic acid, its anhydride or its derivative is preferably 0.05 to 5 mol%, more preferably 0.1 to 3 mol% of the poly-α-olefin.
Is preferred. When the content is less than the above range, the adhesion between the polyamide and the polyolefin phase is insufficient, the structure of the resulting resin composition becomes unstable, and the mechanical strength becomes low, which is not preferable. When it exceeds the above range, the fluidity of the obtained resin composition is deteriorated, which is not preferable in molding.

The grafting of the polyolefin is carried out by heating and stirring the polyolefin and the above α, β-unsaturated carboxylic acid, its anhydride or its derivative together with the radical generator in the molten or solution state of the polyolefin. .

As the poly-α-olefin component unit constituting the modified polyolefin of the present invention, ethylene, propylene, 1-butene, 1-hexene, which is an α-olefin having 2 or more carbon atoms, particularly about 2 to 18 carbon atoms, 1-decene, 1-pentene and the like can be mentioned.
The seeds or they may be mixed.

In the resin composition of the present invention, it is essential that the crystalline ternary copolyamide forms a matrix phase. By forming a continuous phase with the polyamide component (A), it is possible to impart the properties of the polyamide excellent in heat resistance and mechanical properties to the polyamide component (A).
When a discontinuous phase is formed, the resin composition obtained has poor mechanical properties and heat resistance, and the object of the present invention cannot be achieved.

(A) an equimolar salt of hexamethylenediamine and adipic acid in the crystalline ternary copolyamide which is the component (A) used in the resin composition of the present invention,
The compounding ratios of (b) equimolar salt of hexamethylenediamine and terephthalic acid and (c) nylon 11 or nylon 12 forming monomer, respectively, are as follows.

That is, the mixing ratio of the components (a), (b) and (c) is 20 to 80% by weight of the component (a) and 80 to 20% by weight of the component (b). (c) to 100 parts by weight of the total amount of the components a) and (b)
It is suitable to add 0.1 to 30 parts by weight of the components.
(A) component is 25 to 75% by weight, and (b) component is 7
5 to 25% by weight, and the component (c) is 0.5 to 2 with respect to 100 parts by weight of the total amount of the components (a) and (b).
It is particularly preferable to add 0 part by weight.

When the content of the component (a) is 20% by weight or less, the characteristics of the crystalline ternary copolymerized polyamide are impaired, which is not preferable. On the other hand, if it exceeds 80% by weight, the water absorption rate of the molded article increases, which is not preferable. On the other hand, when the amount of the component (b) exceeds 80% by weight, the melting point becomes high as in the case of the component (a), and thermal decomposition occurs during molding, which is not preferable. If it is 20% by weight or less, the water absorption is high, which is not preferable.

If the amount of the component (c) is 0.1 parts by weight or less, thermal decomposition or the like will occur during molding, and the characteristics as the crystalline ternary copolyamide will be impaired, such being undesirable. Three
If it exceeds 0% by weight, the crystallinity is remarkably lowered, and in the case of molding by injection molding, the molding cycle becomes long, which is not preferable.

In the polyamide resin composition of the present invention,
The mixing ratio of the crystalline ternary copolymerized polyamide component (A) and the modified polyolefin component (B) is appropriately 65 to 95% by weight of the polyamide component (A) and 5 to 35% by weight of the modified polyolefin (B) component. . (However, the total of the component (A) and the component (B) is 100% by weight) Particularly preferably, the polyamide component (A) is 70 to 90% by weight, and the modified polyolefin component is 10 to 30% by weight.

When the content of the polyamide component (A) is 65% by weight or less, the heat resistance characteristic of the crystalline ternary copolyamide is impaired, and when the content of the polyamide component (A) exceeds 95% by weight, the impact resistance is high. The improvement effect of is no longer recognized.

The polyamide resin composition can be produced by melt-kneading with a single-screw, twin-screw, or multi-screw extruder, but a kneader or the like can also be used. It is not something that will be done.

Other additives may be used as long as the physical properties of the resin composition are not impaired. For example, pigments, dyes, heat resistance agents, antioxidants, weather resistance agents, lubricants,
Examples include crystal nucleating agents, antistatic agents, plasticizers, and other polymers.

The resin composition of the present invention can be molded into various molded products by known molding methods such as injection molding, extrusion molding, blow molding, vacuum molding and press molding.
It is particularly useful in the fields of injection molding and blow molding.

There is no limitation on the shape of the molded product molded by these, for example, interior / exterior parts of automobiles, parts in engine room and electric parts of automobiles, and electric, electronic parts, electric tools, general industrial parts, gears, cams. It is also suitable for machine parts such as.

The present invention will be described in more detail with reference to the following examples. The physical properties of the test pieces were measured by the following methods.

(1) Relative viscosity: JIS K6810 (2) Tensile test: ASTM D638 (3) Bending test: ASTM D790 (4) Water absorption rate: ASTM D570 (5) Impact test: ASTM D256 (6) Crystallinity: Seiko 10 ° C / using electronic DSC
The crystallinity was evaluated by the appearance of a clear melting endothermic peak (melting point) and a crystallization exothermic peak (crystallization temperature) when the temperature was raised and lowered by min.

Example 1 3 parts by weight of 12-aminododecanoic acid was added to 100 parts by weight of raw material monomer having a weight ratio of 5/5 of hexamethylenediamine / adipic acid equimolar salt and hexamethylenediamine / terephthalic acid equimolar salt. 250 parts under pressure and agitation type polymerization tank
The prepolymer was polymerized under heating conditions of ° C and pressure conditions of 22 kg / cm ² . The relative viscosity of the obtained prepolymer was 1.2.
It was 5. Next, this prepolymer was post-polymerized at a polymerization temperature of 320 ° C. using a twin-screw extruder having an L / D of 42 (UME55; manufactured by Ube Industries, Ltd.) to obtain a strand-shaped post-polymer. . This was pelletized with a pelletizer. The polymer obtained has a relative viscosity of η _r = 2.52 and a melting point of 29.
It was 0 ° C. The crystallization temperature was 254 ° C. 80% by weight of this crystalline ternary copolyamide and 20% by weight of XLD488 manufactured by Ube Industries, which is LLDPE graft-modified with 1 mol% of maleic anhydride as a modified polyolefin.
A twin screw extruder (manufactured by Japan Steel Works;
TEX44) was melt-kneaded at a melting temperature of 315 ° C., pelletized, and dried for evaluation. The results are summarized in Table 1.

Example 2 The weight ratio of the equimolar salt of hexamethylenediamine / adipic acid to the equimolar salt of hexamethylenediamine / terephthalic acid was 12-based on 100 parts by weight of the raw material monomer of 5/5.
A terpolymer was obtained under the same conditions as in Reference Example 1 except that the compounding composition of aminododecanoic acid was 10 parts by weight. The relative viscosity of the prepolymer was η _r = 1.23. The relative viscosity of the post-polymer was η _r = 2.49 and the melting point was 283 ° C. The crystallization temperature was 234 ° C. 80% by weight of this crystalline ternary copolyamide and 20% by weight of XZ488 used in Example 1 as a modified polyolefin were melt-kneaded in a polyamide resin composition in the same manner as in Example 1 for evaluation. I served. The results are shown in Table 1.

Example 3 The weight ratio of the equimolar salt of hexamethylenediamine / adipic acid to the equimolar salt of hexamethylenediamine / terephthalic acid was 12-based on 100 parts by weight of the raw material monomer of 6/4.
A terpolymer was obtained under the same conditions as in Reference Example 1 except that the compounding composition of aminododecanoic acid was 5 parts by weight. The relative viscosity of the prepolymer was η _r = 1.23. The relative viscosity of the post-polymer was η _r = 2.55 and the melting point was 275 ° C. The crystallization temperature was 244 ° C. 80% by weight of this crystalline ternary copolymerized polyamide, Example 1 as a modified polyolefin
The polyamide resin composition was melt-kneaded in the same operation as in Example 1 at a blending ratio of 20% by weight of XZ488 used in Example 1, and the mixture was provided for evaluation. The results are shown in Table 1.

Example 4 The weight ratio of the equimolar salt of hexamethylenediamine / adipic acid to the equimolar salt of hexamethylenediamine / terephthalic acid was 11-5 with respect to 100 parts by weight of the raw material monomer of 5/5.
A terpolymer was obtained under the same conditions as in Example 1 except that the mixing ratio of aminoundecanoic acid was 3 parts by weight. The relative viscosity of the prepolymer was η _r = 1.25. The relative viscosity of the post-polymer was η _r = 2.52 and the melting point was 293 ° C. The crystallization temperature was 257 ° C. 80% by weight of this crystalline ternary copolyamide and 20% by weight of XZ488 used in Example 1 as a modified polyolefin were melt-kneaded in a polyamide resin composition in the same manner as in Example 1 for evaluation. I served. The results are shown in Table 1.

Example 5 80% by weight of the crystalline ternary copolymerized polyamide polymerized in Example 1, 0.4 maleic anhydride as a modified polyolefin
Melt kneading was carried out in the same manner as in Example 1 except that mol% and 20% by weight of graft-modified polypropylene (manufactured by Ube Industries) were used to obtain a resin composition. This resin composition was evaluated. The results are shown in Table 1.

Comparative Example 1 Prepolymerization and post-polymerization under the same conditions as in Reference Example 1 at a compounding ratio of 50% by weight of an equimolar salt of hexamethylenediamine / adipic acid and 50% by weight of an equimolar salt of hexamethylenediamine / terephthalic acid. Was performed to obtain a crystalline binary copolymer.
The relative viscosity of the prepolymer was η _r = 1.25. The relative viscosity of the post-polymer was η _r = 2.50, the melting point was 294 ° C., and the crystallization temperature was 255 ° C. 80% by weight of this crystalline binary copolymerized polyamide and 20% by weight of XZ488 used in Example 1 as the modified polyolefin were melt-kneaded in the same manner as in Example 1 in the same manner as in Example 1 for evaluation. I served. The evaluation results are shown in Table 1.

Comparative Example 2 Prepolymerization and postpolymerization under the same conditions as in Reference Example 1 with the compounding ratios of hexamomethylenediamine / adipic acid equimolar salt 60% by weight and hexamethylenediamine / terephthalic acid equimolar salt 40% by weight. Was performed to obtain a crystalline binary copolymer.
The relative viscosity of the prepolymer was η _r = 1.24. The relative viscosity of the post-polymer was η _r = 2.51, the melting point was 284 ° C., and the crystallization temperature was 250 ° C. 80% by weight of this crystalline binary copolymerized polyamide and 20% by weight of XZ488 used in Example 1 as a modified polyolefin were melt-kneaded in a polyamide resin composition by the same operation as in Example 1 for evaluation. I served. The evaluation results are shown in Table 1.

Comparative Example 3 A polyamide resin composition was prepared in the same manner as in Example 1 except that the binary crystalline aromatic polyamide used in Comparative Example 1 was 80% by weight and the modified polypropylene used in Example 5 was 20% by weight. The product was melt-kneaded and provided for evaluation. The evaluation results are shown in Table 1.

[0040]

[Table 1]

Claims (1)

[Claims] 1. A composition comprising (a) an equimolar salt of hexamethylenediamine and adipic acid, (b) an equimolar salt of hexamethylenediamine and terephthalic acid, and (c) a nylon 11 or nylon 12-forming monomer. A modified polyolefin obtained by graft-polymerizing 65 to 95% by weight of the crystalline ternary copolyamide (A) with a polyolefin of 0.05 to 5 mol% of α, β-unsaturated carboxylic acid, its anhydride or its derivative ( B) A polyamide resin composition comprising 5 to 35% by weight.