JPH03207735A - Resin molding excellent in mechanical characteristics - Google Patents

Abstract

PURPOSE:To provide the subject moldings composed of a polyamide, a polyolefin and a modified polyolefin having specified characteristics and useful for structural members, etc., in the fields of automobile, electricity, electronics, etc. CONSTITUTION:(A) A polyamide such as nylon 6 preferably is blended with (B) a polyolefin, e.g. a polymer of an alpha-olefin such as ethylene and (C) a modified polyolefin prepared by introducing 0.05-10wt.% unsaturated carboxylic acid, etc., preferably into a monomer, etc., of a polyolefin in an amount of 5-95 pts.wt. component (A) and 95-5 pts.wt. components (B+C). The resultant resin composition is subjected to injection molding, e.g. at [melting point of component (A) + 10-30 deg.C] resin temperature, at 40-85 deg.C mold temperature, at 400-550Kg/cm<2> injection pressure and in 60-180 sec residence time in cylinder, thus obtaining the objective molding simultaneously satisfying >=300kg/cm<2> tensile yield strength of component (C) and <=5mum (preferably <=2mum) particle size of particle dispersed in molding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a molded article comprising a polymer blend composition of polyamide and polyolefin.

This molded product is useful as a structural member or mechanical part in the automobile field, electrical/electronic field, and sporting goods field.

[Conventional technology]

Polyamide is highly valued for its excellent mechanical properties and heat resistance, and is widely used in automobile parts and electrical and electronic parts.

However, there are many uses where polyamide's unique water absorption and resulting dimensional changes and changes in various properties are a problem, and for this reason, other olefin polymers are blended to ensure a balance of physical properties. .

On the other hand, polyolefins are used in a wide range of fields because they are relatively inexpensive and have excellent chemical stability. However, as its uses have expanded, polyolefins have been found to have insufficient mechanical strength and heat resistance, and attempts have been made to improve these physical properties by blending them with other polymers, particularly polyamides.

However, originally polyamide and polyolefin are
It is a polymer that does not compatibilize, and simply blending it will cause the polymer to peel off, resulting in products with no commercial value.
There was a problem with it rising. Therefore, in order to make these both polymers compatible, a method using a modified polyolefin (Japanese Patent Publication No. 40-30943),
etc. have been proposed.

[Problem to be solved by the invention]

However, conventional methods, such as methods using modified polyolefins, have been insufficient in compatibility and mechanical strength, particularly weld strength, depending on the type of modified polyolefin.

An object of the present invention is to provide a resin molded product made of polyamide and polyolefin that has excellent compatibility and mechanical properties, particularly weld strength.

[Means to solve the problem]

The inventors believe that in order to achieve the above-mentioned problems, both the strength of the modified polyolefin and the particle size of the dispersed phase in the molded product are
It was discovered that it was necessary to satisfy each specific value at the same time, and the present invention was accomplished. That is, the present invention
(A) Polyamide, (B) Polyolefin, (C)
A composition consisting of a modified polyolefin (C) in which the tensile yield strength of the modified polyolefin is 300 kg/cd or more, and the particle size of the dispersed phase dispersed in a molded article obtained from the composition is 5 μm or less It is a resin molded product with excellent mechanical properties.

The particle size of the dispersed phase in the present invention is the average particle size of the dispersed phase observed with an electron microscope. The molding conditions when molding a molded article vary depending on the polymer that makes up the composition, but
For example, in the case of injection molded products, the resin temperature is 10 to 30 degrees Celsius above the melting point of polyamide, the mold temperature is 40 to 85 degrees Celsius, the injection pressure is 400 to 550 kg/c♂, and the residence time in the cylinder is 60 to 180 degrees Celsius. The general condition is to set the time to seconds.

The present invention can be obtained only when the dispersed particle size is 5 μm or less and the tensile yield strength of the modified polyolefin blended to obtain a molded article is 300 kg/cm 2 or more. The preferred dispersed particle size is 2 μm or less.

When the dispersed particle size is 5 μm or more and the tensile yield strength of the modified polyolefin is less than 300) cg/cd, delamination is likely to occur and mechanical properties, particularly the strength of the weld portion, are reduced. Even if the dispersed particle size is 5 μm or less, if the tensile yield strength of the modified polyolefin is less than 800) cg/cm 2 , the compatibility is improved, but the strength of the weld portion is still insufficient.

In addition, the tensile yield strength of the modified polyolefin is 300) cg
/ cd or more, neither compatibility nor weld strength will be improved if the dispersed particle size is 5 μm or more.

The polyolefins used in the present invention include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1
- Polymers of α-olefins such as hexene, block or random copolymers thereof, and the like are used. A copolymer of the above olefin and a vinyl aromatic compound may also be used. Among these olefins, polypropylene homopolymers and random or block copolymers with other olefins containing a propylene component of 50 mol% or more, preferably 80 mol% or more are preferred. These polyolefins are selected to have a melt viscosity close to that of the polyamide used, and have a melt flow index of 1 to 6.
Preferably it is 0 g/10 minutes. More preferably,
6-50 g/10 minutes.

The modified polyolefin as used in the present invention is a resin obtained by introducing an unsaturated carboxylic acid or a derivative thereof into the above-mentioned polyolefin alone or into a mixture of two or more thereof.

Unsaturated carboxylic acids or derivatives thereof include acrylic acid, maleic acid, fumaric acid, itaconic acid and other unsaturated carboxylic acids or derivatives thereof, such as acid halides, amides,
Examples include imides and acid anhydrides, and specific examples include maleimide, maleic anhydride, itaconic anhydride, and the like. Among these, unsaturated dicarboxylic acids or their acid anhydrides are preferred, and maleic anhydride is particularly preferred.

In producing the above-mentioned modified polyolefin, the above-mentioned polyolefin is suspended or dissolved in a suitable solvent, and the above-mentioned unsaturated carboxylic acid or its derivative and a radical generator are added thereto, followed by heating and stirring (solution method); Alternatively, there is a method in which a polyolefin, an unsaturated carboxylic acid or a derivative thereof, and a radical generator are mixed in advance, and the mixture is melt-kneaded using an extruder, a Banbury mixer, a kneader, or the like.

The amount of unsaturated carboxylic acid or its derivative introduced into the modified polyolefin is preferably 0.05 to 10% by weight.

If the amount is less than 0.05% by weight, it becomes difficult to control the particle size of the dispersed phase of the molded article to 5 μm or less.

The polyamide in the present invention is a polymer compound having acid amide as a repeating unit, and examples thereof include nylon 6, nylon 11, nylon 12, nylon 46, and nylon 6.
6. Nylon 6101, nylon 612, etc. can be used alone or in the form of a copolymer. These polyamides are selected depending on the intended use of the composition, but
It is preferable to use nylon 6 or nylon 66 because they have excellent heat resistance and mechanical properties. Further, the molecular weight of these polyamides is not particularly limited, but those having a relative viscosity (ηrel) of 2.0 or more are usually used.

The composition ratio of (A) to (C) constituting this molded product is (A
) polyamide is 5 to 95 parts by weight, (B) polyolefin + (C) modified polyolefin is 95 to 5 parts by weight, preferably (A) is 10 to 70 parts by weight, (B) + (
C)=90 to 30 parts by weight. (A) If the polyamide content is less than 5 parts by weight, the rigidity and heat resistance will be poor. Also, (B)
When +(C) is less than 5 parts by weight, water absorption becomes high.

Further, the preferable amount of the modified polyolefin varies depending on the amount of unsaturated carboxylic acid or its derivative introduced, but (B)+
(C) = 0.5 to 99 parts by weight per 10 parts by weight. If the amount of the modified polyolefin is less than the above range, it will be difficult to control the particle size of the dispersed phase of the molded article to 5 μm or less.

In the present invention, in addition to the above-mentioned components, inorganic fillers such as oxides such as iron oxide, magnesium oxide, and calcium oxide, and hydrated metals such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide are used. oxides, carbonates such as calcium carbonate, magnesium carbonate, silicates such as talc, clay, etc., or fibrous fillers such as glass fibers, wollastonite, carbon fibers, other glass peas, mica, etc. Agents can be added alone or in combination.

The amount of the filler is preferably 5 to 150 parts by weight, more preferably IO to 100 parts by weight, based on 100 parts by weight of (A) polyamide + (B) polyolefin + (C) modified polyolefin. Heat resistance, tensile strength, etc. are improved. Further, the surface of the filler is preferably treated with a silane compound or the like, and among these, fibrous materials, particularly glass fibers, are preferred because they have an excellent reinforcing effect.

In addition, various additives that are usually added to resins, such as oxidative deterioration inhibitors, heat stabilizers, crystal nucleating agents, and lubricants, may also be added.

In order to obtain the molded article of the present invention, for example, polypropylene, acid anhydride-modified polypropylene, and nylon 66 are blended, and the resulting blend is kneaded using a conventional melt-kneading machine.
For example, it can be obtained by obtaining pellets using an extruder, Brabender roll, etc., and molding the pellets with a molding machine, such as an injection molding machine, but the tensile yield strength of the blended modified polyolefin is 300 kg/cd or more. In addition, it is necessary that the particle size of the dispersed phase in the obtained molded article be 5 μm or less.

Modified polyolefins can be produced by the method described above, but in order to have a tensile yield strength of 300 kg/c+# or higher, a polyolefin with high strength is used and a method that causes less strength loss during modification, such as using a solution, is used. It can be obtained by denaturation or melt denaturation by controlling the crosstalk conditions.

The method for controlling the particle size of the dispersed phase of the molded product to 5 μm or less is not particularly limited, but the following methods may be used alone or in combination.
A combination of two or more is useful.

(1) Method for controlling the amount of unsaturated carboxylic acid or derivative thereof introduced into modified polyolefin By increasing the amount of unsaturated carboxylic acid or derivative thereof introduced, the particle size of the dispersed phase tends to become smaller. The relationship between the amount of unsaturated carboxylic acid or its derivative introduced and the particle size of the dispersed phase differs depending on the structure of the composition, but for example, when the polyamide is 70% by weight, the equivalent amount of unsaturated carboxylic acid or its derivative in the composition, By making the ratio of polyamide to -NH2 equivalent larger than 0.4, the particle size of the dispersed phase can be controlled to 5 μm or less.

(2) Method for controlling the crosstalk method When melt-kneading (A) polyamide, (B) polyolefin, and (C) modified polyolefin, a preferable treatment for reducing the particle size of the dispersed phase is to preliminarily prepare (B). Examples include a method in which (C) is melt-kneaded and then kneaded with (A).

(3) Method of adding the fourth component By adding an appropriate amount of an oligomer or polymer containing an acid anhydride group as the fourth component, the particle size of the dispersed phase can be further reduced. Among these, olefin oligomers containing acid anhydride groups are preferred.

What is an olefin oligomer? (B) Polyolefin,
It is a low-molecular oligomer of a conjugated diene polymer, and may be in liquid form. These are made to contain acid anhydride groups by some means.

Regarding the method of introducing acid anhydride groups, in addition to the method described for modified polyolefins, in the case of hydrogenated conjugated diene polymers, ethylene oxide is added during living polymerization of the conjugated diene compound, and the terminal 10H group is added. It is also possible to take polybutadiene, hydrogenate it, and then bond a compound having an acid anhydride group using the -OH group.

Since the composition of the present invention has excellent compatibility and mechanical properties,
Automotive parts - spoilers, fender emblems, console boxes, instrumental panels, connectors, fasteners, relay boxes, radiator tanks, canisters, wheel covers, hubcaps,
Suitable for fans, power tool housings, motor fans, fan cases, motor covers, cooling fans, pump fans, sports parts, etc.

〔Example〕

Next, the present invention will be explained in detail by giving examples.

The test methods in Examples and the test methods for modified polyolefins are as follows.

(1) Compatibility: The state of peeling was evaluated by observing the fracture surface of the test piece after the tensile test.

(2) Tensile strength and tensile elongation: A 3-inch thick ASTM dumbbell test piece molded using an injection molding machine was tested using a tensile tester at 23° C. and a crosshead speed of 50 mm/min.

(3) Weld part strength: A weld part test piece was prepared using a mold in which molten resin collided in countercurrent to form a weld part. The tensile strength of the test piece was measured.

(4) Molding fluidity: The flow state during injection molding was comparatively evaluated.

(5) Dispersed phase particle size: A test piece prepared for tensile strength evaluation was placed in liquid nitrogen at 30°C.
After soaking for several minutes, the center part of the test piece was cut. After that, when the polyolefin is the dispersed phase, the test piece is heated to about 120°C.
Soaked in decalin for 1 hour.

When polyamide was the dispersed phase, the test piece was immersed in formic acid at room temperature for 30 minutes. After removing the solvent, the cross section of the specimen was
The phase structure was photographed using a scanning electron microscope. From this photograph, the volume average diameter of the dispersed particles dispersed in the sample was measured.

(6) Water absorption rate: A test piece prepared for tensile strength evaluation was soaked in water at 23°C for 2 hours.
A 4-hour water absorption test was conducted, and the water absorption rate (%) was determined from the rate of change in heavy metal of the test piece.

Further, (A) polyamide, (B) polyolefin, and (C) modified polyolefin used on each side are as follows.

(A) Polyamide (1) Nylon 66 Relative viscosity: 2.83 Amino end group concentration: 4.6XIO-” equivalent/g (Leona 1300 manufactured by Fukaisei) (2) Nylon 6 Relative viscosity: 2.37 Amino end group concentration : 6.6X10-” equivalent/g (UBE Nylon 1013B manufactured by Ube) (B) Polyolefin (1) Polypropylene with MFR of 14 g/10 min at 230°C (Asahi Kasei Polypro M 1600 manufactured by Asahi Kasei) (2
) Polypropylene with an MFR of 30 g/40 min at 230°C (Asahi Kasei Polypro M 1700) (C)
Modified polyolefin (1) Modified polypropylene I A modified polypropylene obtained by adding 1.1% by weight of maleic anhydride to tactical polypropylene. The tensile yield strength of this modified polypropylene is 360 kg/cm.
It was 2.

(2) Modified polypropylene ■ Modified polypropylene made by adding 4.3% by weight of maleic anhydride to tactical polypropylene. The tensile yield strength of this modified polypropylene is 350 kg/cd.
Met.

(3) Modified polypropylene ■ Modified polypropylene in which 0.12% by weight of maleic anhydride is added to polypropylene. The tensile yield strength of this modified polypropylene was 280 kg/cd.

(4) Modified polypropylene■ A modified polypropylene obtained by adding 5.5% by weight of maleic anhydride to polypropylene. In addition, the tensile yield strength of this modified polypropylene was 100 kg/C-. Examples 1 to 8 and Comparative Examples 1 to 10 The above (A) polyamide, (B) polyolefin, (
C) Modified polyolefins were blended in the amounts (wt%) shown in Table 1. The obtained blend was kneaded and extruded using a twin-screw mixer (PCM30φ manufactured by Ikegai Iron Works) to obtain pellets.

Samples for evaluating physical properties and characteristics were prepared from each pellet using an injection molding machine and evaluated. The results are shown in Table 2.

Example 9 29 parts by weight of M2SO4 and 3 parts by weight of modified polypropylene I were blended, and this blend was kneaded and extruded using a twin-screw kneader (PCM30φ manufactured by Ikegai Iron Works) to obtain pellets. 32 parts by weight of this pellet and Leona 130
68 parts by weight of 0 were blended, and the mixture was kneaded and extruded using a twin-screw mixer (PCM30φ manufactured by Ikegai Iron Works) to obtain pellets.

A sample for evaluating physical properties and characteristics was prepared from this pellet using an injection molding machine and evaluated. The results are shown in Table 2.

Example 10 6670 parts by weight of nylon, 25 parts by weight of M1700, and 5 parts by weight of modified polypropylene (I) were blended, and 67% by weight of this blend and 33% by weight of glass fiber (FT-2 manufactured by Asahi Fiberglass) were biaxially kneaded. Pellets were obtained by cross-wire extrusion using a machine (PCM45φ manufactured by Ikegai Iron Works). Note that the glass fiber was blended from the sidewall.

Samples for evaluating physical properties and characteristics were prepared from the pellets using an injection molding machine and evaluated. The results are shown in Table 2.

Example 11 Except for using 60 parts by weight of nylon 66, 25 parts by weight of M 1700, and 5 parts by weight of modified polypropylene (I),
The same procedure as in Example 10 was carried out.

Example 12 Except for using 30 parts by weight of nylon 66, 66 parts by weight of M 1700, and 4 parts by weight of modified polypropylene (r),
The same procedure as in Example 10 was carried out.

Example 13 30 parts by weight of nylon 6, 66 parts by weight of M 1700,
The same procedure as in Example 10 was carried out except that the modified polypropylene (1) was changed to 4 parts by weight.

Comparative Example 11 70 parts by weight of nylon 6G and 30 parts by weight of M 1700 were blended, and 67% by weight of this blend and 33% by weight of glass fiber (FT-2 manufactured by Asahi Fiberglass) were blended.
The mixture was kneaded and extruded using a screw extruder (PCM45φ manufactured by Ikegai Iron Works) to obtain pellets. Note that the glass fiber was blended from a side hopper.

Samples for evaluating physical properties and characteristics were prepared from the pellets using an injection molding machine and evaluated. The results are shown in Table 2.

(Left below) [Effects of the Invention] The molded product of the present invention has excellent properties of both polyamide and polypropylene, and has extremely good compatibility. It is useful as a structural material or mechanical part.

Claims (2)

[Claims] (1) (A) Polyamide, (B) Polyolefin, (C
) modified polyolefin, in which (A) is 5
~95 parts by weight, (B) + (C) is 95 to 5 parts by weight, and the tensile yield strength of (C) modified polyolefin is 300 parts by weight.
A resin molded article with excellent mechanical properties, characterized in that the particle size of the dispersed phase dispersed in the molded article obtained from the composition is 5 μm or less. (2) The resin molded article with excellent mechanical properties according to claim 1, which also contains glass fiber.