JPH0931325A - Polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyamide resin composition which can give a molding having resistance to surface delamination and very excellent impact strength. SOLUTION: This resin composition is the one comprising 90-50wt.% continuous phase comprising a polyamide resin and 10-50wt.% particulate dispersed phase comprising a polyolefin modified with an α,β-unsaturated carboxylic acid and dispersed in the continuous phase, wherein the number-average particle diameter of the dispersed phase is 0.27μm or below, and the rate of the dispersed phase with particle diameters of 0.5μm or above is 4% or below, based on the total dispersed phase.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition comprising a polyamide resin and a modified polyolefin such as modified polypropylene, and more particularly to a polyamide resin composition having excellent impact resistance.

[0002]

2. Description of the Related Art Impact resistance of polyamide resin, low water absorption,
Modified polyolefins have been added to improve dimensional stability and the like. For example, JP-A-51-14
No. 3061 is a polyamide matrix resin with 0.01
It has been shown that toughness or ductility is improved in multi-phase thermoplastic compositions having a particle size in the range of ˜3.0 μm and containing polymer particles adhered to a polyamide matrix resin.

When producing a thermoplastic resin composition in which a modified polyolefin phase is dispersed in a particle shape in a polyamide resin matrix, the polyamide resin and the modified polyolefin are usually melted and kneaded by an extruder, but melted.
The average particle size of the dispersed phase composed of the modified polyolefin in the resin composition obtained by kneading is 0.01 to 3.0 μm.
It was difficult to make the impact strength high enough to satisfy it, even if it was a little.

[0004]

An object of the present invention is to provide a thermoplastic resin composition comprising a continuous phase, which is a dispersed phase composed of a polyamide resin, and a dispersed phase composed of a modified polyolefin. It is an object of the present invention to provide a polyamide resin composition having excellent impact strength and suppressing the surface peeling of a molded product.

[0005]

The present invention has been made in order to solve the above-mentioned problems, and the gist thereof is 90 to 50% by weight of a continuous phase made of a polyamide resin, and the continuous phase dispersed in the continuous phase. Further, a particulate dispersed phase 10 to 50 comprising a polyolefin modified with α, β-unsaturated carboxylic acid
And the number average particle diameter of the dispersed phase is 0.27.
A polyamide resin composition having a particle diameter of 0.5 μm or less and a proportion of a dispersed phase having a particle diameter of 0.5 μm or more is 4% or less based on the entire dispersed phase.

Hereinafter, the present invention will be described in detail. The continuous phase composed of the polyamide resin in the present invention mainly comprises a polyamide resin component. The polyamide resin component is a polyamide obtained by polycondensation of a lactam having 3 or more membered rings, a polymerizable ω-amino acid, a dibasic acid and a diamine. Specifically, ε-caprolactam,
Polymers such as aminocaproic acid, enanthlactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone and α-piperidone, hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylene Polymers obtained by polycondensing diamines such as diamine and metaxylylenediamine with dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, sebacic acid, dodecane dibasic acid and glutaric acid, or copolymers thereof , Nylon 4, 6, 7, 8, 11, 12, 6.6, 6.9,
6.10, 6.11, 6.12, 6T, 6/6 ・ 6, 6
/ 12, 6 / 6T and the like.

In the present invention, a particulate disperse phase composed of a modified polyolefin is dispersed in a continuous phase composed of a polyamide resin component.
It is a polyolefin modified with α, β-unsaturated carboxylic acid. Examples of the polyolefin in the present invention include polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-vinyl acetate copolymer and the like.

Preferred are polypropylene, polypropylene and ethylene-propylene copolymer, or polypropylene and ethylene-butene copolymer. The most preferred polyolefins from the viewpoint of improving impact strength are:
Examples include polypropylene and ethylene-butene copolymers. Examples of the α, β-unsaturated carboxylic acid or its derivative in the present invention include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, and anhydrides of these acids. Among these, maleic anhydride is used. Alternatively, a mixture of maleic anhydride and another α, β-unsaturated carboxylic acid is preferable.

The α, β-unsaturated carboxylic acid-modified polyolefin in the present invention is usually obtained by melting and kneading the above-mentioned polyolefin and α, β-unsaturated carboxylic acid in the presence of an organic peroxide. can get. The organic peroxide may be any organic peroxide that is usually added when graft-polymerizing an unsaturated carboxylic acid to a polyolefin, and a suitable representative example is 1.1-
Ketone peroxide such as bis-tertiary-butylperoxy-3.3.5-trimethylcyclohexane, dialkyl peroxide such as dicumyl peroxide, 2
・ Hydroperoxide such as 5-dimethylhexane-2,5-dihydroperoxide, acyl peroxide such as besozoyl peroxide, and peroxyester such as 2,5-dimethyl-2,5-dibenzoylperoxyhexane Can be given.

The amount ratio of the polyolefin, α, β-unsaturated carboxylic acid and organic peroxide used is usually 0.01 to 100 parts by weight of the unsaturated carboxylic acid to 100 parts by weight of the polyolefin.
5 parts by weight, preferably 0.05 to 1.5 parts by weight, 0.001 to 0.5 parts by weight of organic peroxide, preferably 0.00
5 to 0.1 parts by weight. If the amount of α, β-unsaturated carboxylic acid is small, the reaction between the modified polyolefin and the polyamide resin will be insufficient, and the impact resistance of the resulting composition will be impaired, and the compatibility between the two will be poor. It is not preferable because the surface of the molded product is peeled off.

If the amount of α, β-unsaturated carboxylic acid is large, unmodified α, β-unsaturated carboxylic acid will be present in the resin composition, resulting in poor thermal stability. The weight ratio of the continuous phase composed of the polyamide resin to the particulate dispersed phase composed of the polyolefin modified with α, β-unsaturated carboxylic acid in the present invention is 90 to 50:10 to 50. If the proportion of the continuous phase made of polyamide resin is high, the impact strength becomes insufficient, and if it is low, the rigidity becomes low. The ratio of the continuous phase to the dispersed phase is more preferably 8 by weight.
5-60: 15-40.

In the polyamide resin composition of the present invention, the number average particle size of the dispersed phase comprising a polyolefin modified with α, β-unsaturated carboxylic acid is 0.27 μm or less, and the particle size is 0.5 μm. The proportion of the above dispersed phase is 4% or less with respect to the entire dispersed phase. When the number average particle diameter of the dispersed phase exceeds 0.27 μm, the impact strength is low, and the proportion of the dispersed phase having a particle diameter of 5 μm or more is 4% with respect to the entire dispersed phase.
If it exceeds, the impact strength will be low as well. The number average particle diameter of the dispersed phase is preferably 0.27 to 0.1 μm, more preferably 0.27 to 0.15 μm.

In order to further improve the impact strength, the ratio of the dispersed phase having a particle diameter of 0.5 μm or more is 3% or less with respect to the entire dispersed phase in the particulate dispersed phase made of the modified polyolefin. preferable. The number average particle size and particle size distribution of the particulate disperse phase composed of such a modified polyolefin are observed and photographed by a transmission electron microscope with a CCD camera, and NIH Image (public domain software) on Macintosh is used. V
er. 1.55) to measure the size of the particulate dispersed phase.

According to such electron micrographs, the polyamide resin composition of the present invention shows that the modified ethylene-butene copolymer and the modified ethylene-butene copolymer are contained in the particulate dispersion phase of the modified polypropylene dispersed in the continuous phase of the polyamide resin. It has been observed that a polyamide resin is present and has a so-called salami structure. As a method for controlling the particle size of the modified polyolefin dispersed in the polyamide resin, the kneading conditions are usually selected appropriately.

That is, a polyamide resin and a modified polyolefin are blended and melted and kneaded by using an extruder or the like. The extruder is usually a single-screw extruder, a twin-screw co-rotating screw extruder, a twin-screw different-direction screw extruder, and the like, and a bi-screw co-rotating screw extruder is particularly preferable.

In molten steel kneading with an extruder, the thermoplastic resin composition of the present invention can be obtained by appropriately selecting the screw configuration, screw rotation speed, barrel set temperature extrusion rate and the like. Generally, it is preferable to increase the kneading strength in order to make the number average particle diameter of the dispersed phase composed of the modified polyolefin 0.27 μm or less. If the kneading strength is weak, the number average particle diameter tends to increase.

In addition, in the case of a particulate disperse phase composed of a modified polyolefin, the proportion of the disperse phase having a particle diameter of 0.5 μm or less is 4% or less with respect to the whole disperse phase, in general, extrusion is performed. In the melting and kneading by a machine, it is preferable to make the extrusion amount relatively large. If the extrusion amount is small, the residence time in the extruder becomes long, and the proportion of the dispersed phase exceeding 0.5 μm exceeds 4%. As for the polyolefin, the modified polyolefin is easily decomposed to cause coloring and strength reduction.

However, if the extrusion amount is too large, the reaction between the polyolefin and the α, β-unsaturated carboxylic acid and / or the reaction between the modified polyolefin and the polyamide is insufficient, which is not preferable. Further, if only the screw rotation speed is increased with the same extrusion amount, the number average particle diameter becomes large and the ratio of the dispersed phase having a particle diameter of 0.5 μm or more to the entire dispersed phase tends to increase, which is not preferable. . Further, if the screw rotation speed is too high, the polyolefin or modified polyolefin is easily dispersed and colored, and if the screw rotation speed is too low, the reaction between the polyolefin and the α, β-unsaturated carboxylic acid and / or the reaction between the modified polyolefin and the polyamide are insufficient. .

The barrel set temperature is 180 to 290 ° C, preferably 190 to 270 ° C. If the barrel setting temperature is too high, the polyolefin or modified polyolefin is likely to decompose to cause coloration or strength reduction, and if the barrel setting temperature is too low, the reaction between the polyolefin and the α, β-unsaturated carboxylic acid and / or the modified polyolefin. The reaction between the and polyamide tends to be insufficient.

In the polyamide resin composition of the present invention, in addition to the polyamide resin and the modified polyolefin, if necessary, an antioxidant, a colorant, a flame retardant, a hydrocarbon that is liquid at room temperature for spreading, a release agent, Glass fiber, clay, silica,
It may contain a known additive such as alumina, further,
A small amount of thermoplastic resin may be contained within a range that does not impair the properties of the polyamide resin composition of the present invention.

[0021]

〔Evaluation methods〕

(Izod impact value) Injection molding machine (Nissei Plastic Industry FS80
12 ASE) using a test mold defined by ASTM, resin temperature 250 to 260 ° C., mold temperature 70 to 8
Molded at 0 ℃ to obtain a test piece, Izod
Impact strength was measured according to ASTM-D256.

(Measurement of particle size) Thin sections were prepared from Izod impact test pieces, and (1) osmium tetroxide staining and / or (2) phosphotungstic acid staining were performed to increase contrast and facilitate morphological analysis. An observation photograph was taken using a transmission electron microscope (H-7000 type manufactured by Hitachi Ltd.). The obtained photograph was subjected to image analysis to measure the particle size using NIH Image (Ver. 1.55).

[Example 1 and Comparative Examples 1 and 2] 22.2% polypropylene (Novatech 4100B manufactured by Mitsubishi Chemical Corporation: Novatec is a registered trademark) and an ethylene-butene copolymer (Tufmer A manufactured by Mitsui Petrochemical Co., Ltd.) -4085) 7.5%
Organic peroxide (Perbutyl P manufactured by NOF CORPORATION):
A solution of 0.015% dissolved or diluted in 0.028% of a liquid hydrocarbon (NAS-4 manufactured by NOF CORPORATION) at room temperature was added and blended with a tumbler for 10 minutes, and then 0.18% of maleic anhydride was added. In addition, after blending again for 10 minutes with a tumbler, the extruder (from TDK Japan Steel Works) was fed from the first feeder.
EX65HCT co-rotating screw extruder).

Takeover nylon 6 (polyamide resin) 6
9.177% (Novamid 1010 manufactured by Mitsubishi Chemical Corporation)
J; 48.477% and Novamid 1020J: 2
0.7%), 0.5% of an antioxidant and 0.5% of a dispersant were dry-blended, supplied from a second feeder and melted and kneaded under the kneading conditions shown in Table-1. The obtained pellets were vacuum dried at 120 ° C. for about 10 hours, and test pieces were molded and evaluated. The results are shown in Table 1.

[Comparative Example 3] Modified polypropylene (Novatech AP390P manufactured by Mitsubishi Chemical Corporation: Novatec is a registered trademark) 22.5% and modified ethylene-butene copolymer (Novatech AP730T manufactured by Mitsubishi Chemical: Novatec is a registered trademark) 7 0.5% and nylon 69.0% (Mitsubishi Chemical Co., Ltd. Novamid 1010J: 48.0% and 1020J:
21.0%), 0.5% of antioxidant and 0.5% of dispersant are blended in a tumbler and supplied to an extruder (VS90-ZB single screw extruder manufactured by Tanabe Plastic Co., Ltd.) using a feeder. Then, they were melted and kneaded under the kneading conditions shown in Table-1. The obtained pellets were dried at 120 ° C. for about 10 hours, molded into test pieces, and evaluated. The results are shown in Table 1.

[0026]

[Table 1]

[0027]

EFFECTS OF THE INVENTION The polyamide resin composition obtained according to the present invention is used for various injection-molded products and extrusion-molded products because the surface peeling of the molded product is suppressed and the impact strength is extremely excellent. You can

Claims (3)

[Claims] 1. A continuous phase 90 to 5 comprising a polyamide resin.
0% by weight and 10 to 50% by weight of a particulate dispersed phase composed of a polyolefin modified with an α, β-unsaturated carboxylic acid, dispersed in the continuous phase, and having a number average particle diameter of the dispersed phase. Is 0.27 μm or less, and the particle size is 0.
A polyamide resin composition in which the proportion of the dispersed phase of 5 μm or more is 4% or less based on the entire dispersed phase. 2. The polyolefin is one or more selected from polypropylene, ethylene-butene copolymer and ethylene-butene copolymer.
The polyamide resin composition according to item 1. 3. The number average particle diameter of the dispersed phase is 0.27 to 0.
It is 1 micrometer, The polyamide resin composition of Claim 1 or 2 characterized by the above-mentioned.