JPH0649823B2 - Polyamide composition - Google Patents

Description

The present invention relates to a polyamide composition for molding.

[Problems to be Solved by Conventional Techniques and Inventions] Polyamide resins are widely used in various fields as engineering plastics because they have excellent mechanical strength.

However, it has a drawback that the tensile elongation becomes small depending on the use conditions.

As a method of solving this drawback, there is a method of improving tensile elongation by copolymerizing polyalkylene glycol,
This method reduces the tensile strength and heat resistance.

The present invention has been made in order to obtain a composition which gives a molded article having excellent tensile elongation without lowering tensile strength, thermal stability and impact strength.

[Means for Solving Problems] In the present invention, (i) 100 parts by weight of polyamide resin (parts by weight, the same applies hereinafter), and (ii) (a) polyester segment of 45 to 90% (% by weight, applies similarly below) (b) General formula (I) having an average molecular weight of 400 to 3000: (In the formula, R represents a C _{2 to} C ₄ hydrocarbon group, X represents a divalent bonding group or a direct bond, and m and n are 5 to 5 respectively.
A polyester ether block copolymer consisting of 10 to 55% of a polyalkylene glycol segment represented by
It relates to a polyamide composition containing 35 parts.

[Example] As the polyamide resin used in the present invention, ε-caprolactam, 6-aminocaproic acid, ω-enanthlactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α- Polymers from piperidone, etc., diamines such as hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, metaxylylenediamine and dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, sebacic acid, etc. Polymers obtained by condensation, copolymers from the above monomers, and the like can be used.

The polyester ether block copolymer used in the present invention is a block copolymer composed of polyester and a specific polyalkylene glycol.

Examples of the polyesters include polyesters composed of terephthalic acid and glycols having 2 to 4 carbon atoms, and examples of glycols having 2 to 4 carbon atoms include ethylene glycol, propylene glycol and butanediol.

The glycol and terephthalic acid constituting the polyester contain other glycols (eg, hexanediol, cyclohexanedimethanol, etc.) and other dicarboxylic acids (eg, isophthalic acid, naphthalenedicarboxylic acid, etc.) in an amount of 10 mol% or less, respectively. You may stay.

As the polyalkylene glycol, a polyalkylene glycol which gives a polyalkylene glycol segment represented by the general formula (I) and having a molecular weight of 400 to 3000, preferably 500 to 2000 can be used.

(In the formula, R represents a C _{2 to} C ₄ hydrocarbon group, X represents a divalent bonding group or a direct bond, and m and n each represent an integer of 5 to 20.) In the above general formula (I), As specific examples of those shown, for example, R is an ethylene group, a propylene group, a tetramethylene group or other C _{2 to} C ₄ hydrocarbon group, and X is Divalent hydrocarbon group such as -CH ₂ CH _2- , -S-, -O-, -SO _2- , -C
O-, -NY- (wherein Y is a hydrogen atom, a C ₁ -C ₅ substituted or unsubstituted alkyl group) or a bonding group or a direct bond,
Examples thereof include those in which m and n are each an integer of 5 to 20. Note that X is (In the formula, Y is the same as above), —O— or —SO ₂ — is particularly preferable from the viewpoint of moldability. Further, those in which the benzene nucleus is substituted with an alkyl group such as a methyl group or an ethyl group or a halogen atom can also be used.

The degree of polymerization of the polyalkylene glycol is preferably 20 or less for each of m and n from the viewpoint of thermal stability and solvent resistance, and preferably 5 or more for m and n from the viewpoint of crystallization characteristics and impact resistance. .

In a preferred embodiment of the present invention, the polyester segment is a polyethylene terephthalate segment,
In the case where X in (I) is an isopropylidene group and m and n are 5 to 10, respectively.

The proportion of the polyalkylene glycol segment in the polyester ether block copolymer is 10 to 55%, preferably 15 to 50%. If the amount is less than 10%, the tensile elongation of the obtained molded product cannot be improved, and if it exceeds 55%, the heat distortion temperature and the tensile strength of the molded product decrease.

Logarithmic viscosity of polyester ether block copolymer (I
V) is 0.5 to 50 at a concentration of 0.5 g / dl at 25 ° C. in a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio).
A range of 1.4 is preferred. If the IV is less than 0.5, the tensile strength tends to decrease, and if the IV exceeds 1.4, phase separation tends to occur during blending. A more preferable IV is 0.6 to 1.2, and a particularly preferable IV is 0.7 to 1.0.

The amount of the polyester ether block copolymer added to 100 parts of the polyamide resin is 2-35 parts, preferably 5-30 parts.
It is a department. If the amount is less than 2 parts, no improvement in tensile elongation is observed, and if it exceeds 35 parts, the tensile strength and heat distortion temperature decrease.

The method of blending the polyester ether block copolymer with the polyamide is not particularly limited, but generally, a method of melt kneading the polyamide resin and the polyester ether block copolymer using an extruder is generally used.

If desired, the composition of the present invention may include other known resins such as polyethylene, polypropylene, EP rubber, ethylene-
Resins such as vinyl acetate copolymers, ionomers, ABS resins, nylons, PBT resins, PET resins may be added to give different characteristics, and also glass fibers, glass beads, carbon fibers, steel fibers, talc. , Clay, calcium carbonate, calcium sulfate, mica and the like filler, carbon powder, zinc oxide, titanium oxide and the like pigments, dyes, antioxidants, ultraviolet absorbers, flame retardants and the like may be added.

Hereinafter, the composition of the present invention will be described with reference to examples, but the present invention is not limited thereto.

The tensile strength, tensile elongation, and tensile modulus of the test pieces in the examples are ASTM-D638, and the heat distortion temperature (weight of 4.6 kg / cm ₂ ) is ASTM.
-D648, notched Izod impact strength was measured according to ASTM-D256. The thermal stability was judged by coloring the resin when it stayed in an injection molding machine at 260 ° C. for 5 minutes. When there was no coloring, it was marked with ⊚, and when slightly colored, it was marked with ◯.

Examples 1 to 3 and Comparative Examples 1 to 2 Polyethylene terephthalate block copolymers (IV = 100 parts by weight of nylon 6 and 30% of ethylene oxide adduct of bisphenol A (number average molecular weight 1000))
0.80) was dry-blended in the proportions shown in Table 1, extruded by a twin-screw extruder into pellets, and test pieces were prepared by injection molding, and the mechanical strength was tested. The results are shown in Table 1.

As Comparative Example 1, a product not containing the above polyester ether block copolymer, and as Comparative Example 2 was added 40 parts and tested in the same manner. The results are shown in Table 1.

Comparative Example 3 Same as Example 1 after dry blending 100 parts of nylon 6 and 10 parts of polyethylene terephthalate block copolymer (IV = 0.8) obtained by using 30% of polyethylene glycol (number average molecular weight 600). And tested. The results are shown in Table 1.

Comparative Example 4 100 parts of nylon 6 and 10 parts of polybutylene terephthalate block copolymer (IV = 1.1) obtained by using 30% of polytetramethylene glycol (number average molecular weight 1300) were dry blended, Tested as in 1. The results are shown in Table 1.

From the results shown in Table 1, the tensile elongation of the molded article obtained by using the composition of the present invention was greatly improved, the thermal stability was also improved, and the tensile strength, the heat distortion temperature, and the notched Izod impact strength were improved as a whole. It can be seen that the performance is almost the same.

Further, when polyalkylene glycol represented by the general formula (I) is used (Example 2) and when other ones are used (Comparative Example 3 using polyethylene glycol and polytetramethylene glycol Comparing with the used Comparative Example 4), it can be seen that when the one represented by the general formula (I) is used, both the heat distortion temperature and the heat stability are better and the heat resistance is excellent.

[Effect of the Invention] When a molded product is produced using the composition of the present invention, a molded product having a large tensile elongation can be obtained without lowering the tensile strength, thermal stability and impact strength of the polyamide resin molded product.

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Claims (1)

[Claims] 1. A general formula (I) having (i) 100 to 100 parts by weight of a polyamide resin, (ii) (a) 45 to 90% by weight of polyester segment and (b) an average molecular weight of 400 to 3000: (In the formula, R represents a C _{2 to} C ₄ hydrocarbon group, X represents a divalent bonding group or a direct bond, and m and n are 5 to 5 respectively.
A polyester ether block copolymer 2 consisting of 10 to 55% by weight of a polyalkylene glycol segumet represented by
A polyamide composition containing 35 parts by weight.