JP3403433B2 - Resin composition having improved weld strength and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide / polyolefin alloy, and more specifically, when a polyamide / polyolefin alloy is obtained, a small amount of a metal salt of a higher aliphatic carboxylic acid is blended and molded to combine the respective characteristics. The present invention relates to a resin composition capable of obtaining a polyamide / polyolefin alloy molded article having improved weld strength strength, elongation and moldability, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, studies have been made to melt mix polyamide and polyolefin to improve physical property deterioration and dimensional change due to water absorption, which is a drawback of polyamide, and to improve heat resistance of polyolefin. If polyolefins are simply melt-mixed due to differences in polarity, phase separation will occur and they will have no commercial value. In order to improve these, a modified polyolefin obtained by reacting a polyolefin with an acid anhydride is further added (JP-A-60-170665). However, the composition obtained by this technique has low weld strength / elongation when formed into a molded product, and its use is greatly limited in the use of a molded product in which a weld portion is generated.

Further, the polyamide / modified polyolefin alloy has a high viscosity as a whole system because of the reaction between the two, and in the case of injection molding, especially thin or large injection molding, short shots, flow marks, etc. are apt to occur. There is a problem in moldability, and in order to improve these problems, attempts have been made to add a small amount of a carboxylic acid compound to obtain an arbitrary melt viscosity (JP-A-4-93353).
However, if a carboxylic acid compound is added during melt mixing, the viscosity of the polyamide and the modified polyolefin will decrease during melt mixing of the polyamide, and the viscosity of the modified polyolefin will be unbalanced, resulting in insufficient mixing, resulting in a weld strength. However, there is also a problem in that the elongation, impact resistance, etc. may be deteriorated.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a molded product comprising a polyamide / polyolefin alloy resin composition having the above-mentioned problems of improved strength, elongation and moldability of the weld portion and exhibiting an excellent property balance. It is something to try.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have noticed that the weld properties of polyamide / polyolefin alloys are related to their morphology, and Suppressing deformation due to shearing of polyolefin dispersed particles enhances weld characteristics, and for that purpose, polyamide,
Instead of melt-mixing the polyolefin and the higher aliphatic carboxylic acid metal salt at once, the polyamide and the polyolefin are once melt-mixed, and then the higher aliphatic metal carboxylic acid metal salt is blended into this mixture to form a dispersed phase. It was found that the orientation of the polyolefin in the weld portion can be suppressed, and the weld strength, elongation and moldability are remarkably improved by this, and the present invention was completed.

That is, the present invention relates to (A) polyamide 6
0 to 90 parts by weight, (B) 100 parts by weight of a resin mixture obtained by melt-mixing with 10 to 40 parts by weight of a polyolefin partially or entirely modified with an acid anhydride, and (C) a step.
Calcium formate, aluminum stearate, stea
Magnesium formate, zinc stearate, stearin
Lithium acid, barium stearate, calci laurate
Um, barium laurate, zinc laurate, montan
Selected from sodium acidate and calcium montanate
A resin composition comprising 0.1 to 3 parts by weight of one or more higher aliphatic carboxylic acid metal salts, wherein (A) 60 to 90 parts by weight of polyamide and (B) all or a part thereof is modified with an acid anhydride. Polyolefin 10-40
After melt-mixing the parts, to the molten mixture (C) stearyl
Calcium formate, aluminum stearate, stea
Magnesium formate, zinc stearate, stearin
Lithium acid, barium stearate, calci laurate
Um, barium laurate, zinc laurate, montan
Selected from sodium acidate and calcium montanate
The present invention relates to a method for producing a resin composition, which comprises mixing 0.1 to 3 parts by weight of one or more metal salts of higher aliphatic carboxylic acid and molding the mixture.

In the present invention, the component (A) is a polyamide, specifically, ε-caprolactam, aminocaproic acid, enanthlactam, 7-aminoheptanoic acid, 1
Polymers such as 1-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone and α-piperidone, diamines such as hexamethylenediamine, nonamethylenediamine, undecamethylenediamine and metaxylylenediamine, and terephthalic acid, isophthalic acid , Adipic acid, sebacic acid, dodecane dibasic acid, a polymer obtained by polymerizing with a dicarboxylic acid such as glutaric acid, or a copolymer thereof, such as nylon 4, 6, 7, 8, 11, 1
2, 66, 69, 610, 611, 612, 6T (hereinafter, T represents terephthalic acid), 6/66, 6/1
2, 6 / 6T, 66 / 6T, etc. can be illustrated. Further, a mixture or a copolymer of these may be used, but nylon 6,66 is preferable among them. Although the molecular weight of the polyamide is not particularly limited, one having a relative viscosity (η rel) of 1.5 or more, preferably 2.0 or more is usually used.

In the present invention, the component (B) is a polyolefin partially or wholly modified with an acid anhydride. The polyolefin may be a mixture of modified polyolefin and unmodified polyolefin. The modified polyolefin and the unmodified polyolefin may be the same or different. As the polyolefin for obtaining the modified polyolefin, a homopolymer of propylene or α-of propylene such as ethylene, 1-butene, 4-methyl-1-pentene and 1-hexene is used.
Block or random copolymer with olefin,
Examples thereof include homopolymers of ethylene, copolymers with other olefins, and mixtures thereof. These polyolefins are MFR (ASTM D1238
The range of 0.1 to 100 g / 10 minutes is preferable. The above polyolefin may contain a small amount of a polyolefin-based elastomer, for example, ethylene / propylene rubber, ethylene / butene rubber, propylene / butene rubber, ethylene / propylene / diene rubber terpolymer. .

The acid anhydride of the present invention includes, for example, acrylic acid, methacrylic acid, maleic acid, succinic acid, fumaric acid,
The itaconic acid, the anhydride of a hymic acid, etc. can be illustrated. Of these, it is most preferable to use maleic anhydride. In order to produce the modified polyolefin of the above (B), any conventionally known technique may be used, but a polyolefin, an acid anhydride and an organic peroxide are mixed in advance, and an extruder, a Banbury mixer, a kneader and the like are used. A method of melt mixing by using is preferably adopted. Examples of the organic peroxide used for modification herein include dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t
-Butylperoxy) hexane, 2,5-dimethyl-
Organic peroxides such as 2,5-di (t-peroxy) hexene-3, lauroyl peroxide and t-butylperoxybenzoate are preferably used. The reaction amount of the acid anhydride with the polyolefin is preferably 0.1 to 5.0 parts by weight, more preferably 0.5 to 2.0 parts by weight, based on 100 parts by weight of the polyolefin.

The blending amount of (A) polyamide and (B) modified polyolefin is 60 to 90 parts by weight, preferably 65 to 80 parts by weight for the former (A) and 10 to 4 for the latter (B).
It is 0 parts by weight, preferably 20 to 35 parts by weight. When the blending amount of the polyamide is 60 parts by weight or less, the polyolefin becomes a matrix phase and the heat resistance is drastically lowered, which is not preferable. Further, when the blending amount of the polyamide is 90 parts by weight or more, the effect of improving the water absorption property, impact resistance and the like cannot be recognized.

In the present invention, the component (C) is a metal salt of higher aliphatic carboxylic acid, which is calcium stearate, aluminum stearate, magnesium stearate, zinc stearate, lithium stearate, barium stearate, calcium laurate, Examples thereof include barium laurate, zinc laurate, sodium montanate, calcium montanate and the like.

The amount of the higher aliphatic carboxylic acid metal salt added is 0.1 to 3 with respect to the total of (A) and (B).
Parts by weight, preferably 0.5 to 1.5 parts by weight. If the compounding amount of the higher aliphatic carboxylic acid metal salt is 0.1 part by weight or less, the effect of improving the weld strength is not recognized,
When the amount is 3 parts by weight or more, the molecular weight of polyamide is drastically reduced, which results in a brittle material, which leads to a reduction in elongation and impact resistance, and a higher aliphatic metal carboxylate precipitates from the molded product during molding, resulting in mold deposits, etc. It is not preferable because it causes the adverse effect of.

The method for producing a polyamide / polyolefin of the present invention comprises the steps of melt-mixing (A) polyamide and (B) modified polyolefin using a conventionally known melt-mixing apparatus such as an extruder, a Banbury mixer, a kneader, etc. , A powder, a pulverized body, etc., and the method of mixing the granular body and the (C) higher aliphatic carboxylic acid metal salt and molding the mixture.
When (A) polyamide and (B) modified polyolefin are mixed by a melt mixing device such as an extruder, (C) higher aliphatic carboxylic acid metal salt is supplied through a vent port or the like opened in a cylinder part in the middle of the extruder. It is also possible to mix and mold in a side feed format or the like. In addition to injection molding, conventionally known molding methods such as compression molding, extrusion molding and stamping molding can be performed in the same manner.

Further, the composition of the present invention comprises (A),
In addition to the components (B) and (C), glass fiber,
Inorganic reinforcing materials such as talc, mica, kaolin, and ceramic fibers, as well as dyes, pigments, fillers, nucleating agents, other fibrous substances, plasticizers, lubricants, coupling agents, foaming agents, heat-resistant agents,
It is also possible to add a proper amount of weathering agent or flame retardant.

[0015]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. The raw materials and chemicals used in the following examples are shown below. Polyamide: Nylon 66 Relative viscosity 2.9 measured with 98% sulfuric acid 1% solution, amino terminal group 4.5 × 10 ⁻⁵ equivalent / g Modified polyolefin: Polypropylene (Asahi Kasei Corp.
Made polypropylene homopolymer, MFR = 0.5g / 1
(0 minutes) 0.5 parts by weight of maleic anhydride (Crystal MAN manufactured by NOF Corporation) and 0.2 parts by weight of organic peroxide (Perhexa25B manufactured by NOF Corporation) were added to 100 parts by weight of (0 minutes). Cylinder temperature 1 with a 70mmΦ single screw extruder (L / D = 30.5)
Melt mixing was performed while degassing from a vent hole on the way at 80 ° C. and a screw rotation speed of 80 rpm to obtain resin pellets.
The MFR of the resulting pellets is 35 g / 10 minutes,
The pellets obtained were hot-pressed and the absorption peak of maleic anhydride was examined by infrared absorption analysis. As a result, the amount of maleic anhydride reacted was 0.3% by weight. Polyolefin: Polypropylene homopolymer manufactured by Asahi Kasei Co., Ltd., MFR = 30 g / 10 min Calcium stearate; Calcium stearate S manufactured by NOF CORPORATION In addition, various polyamide / polyolefin alloy resin compositions obtained in the following examples. The physical properties were measured using the following test methods. (1) Tensile strength and elongation: Tensile strength and elongation were measured according to ASTM D-638. The test pieces for measuring the tensile strength and the elongation of the weld were molded by injection molding using the mold shown in FIG. (2) Water absorption rate: A flat plate of 66 × 90 × 3 mm was molded by injection molding, and the weight was measured immediately after molding. This flat plate 2
After soaking in 3 ° C water for 24 hours, remove and wipe with a dry cloth at a temperature of 23 ° C and humidity of 50% RH for 30
I left it for a minute. Then, the weight was measured again to obtain the water absorption. (3) MFD (mold flow distance) I manufactured by Toshiba Machine Co., Ltd. using an MFD mold as shown in FIG.
Molding was carried out using an S-50EP injection molding machine under the conditions of a cylinder temperature of 280 ° C., an injection pressure of 430 Kg / cm ² , an injection speed of 50% and a molding cycle of 45 seconds / shot, and the resin flow length was measured.

[0016]

Example 1 Polyamide 6.5 kg, modified polyolefin 2.5
of PCM-30 mmΦ (L / D manufactured by Ikegai Iron & Steel Co., Ltd.)
= 17) Pellets (granular material having a length of 2 to 4 mm and a thickness of 1 to 4 mm) were prepared by melt mixing using an extruder. 5 kg of the obtained pellet was dry blended with 10 g of calcium stearate.
Specimens for each test were prepared using an S50EP molding machine. When this test piece was stored in a desiccator for 24 hours and various physical properties were measured, the physical properties shown in Table 1 were obtained.

[0017]

Example 2 A test piece was prepared and measured in the same manner as in Example 1 except that 25 g of calcium stearate was added to 5 kg of the resin composition, and the results were as shown in Table 1.

[0018]

Example 3 A test piece was prepared and measured in the same manner as in Example 1 except that 45 g of calcium stearate was added to 5 kg of the resin composition, and the results were as shown in Table 1.

[0019]

Example 4 8.0 kg of polyamide, 1.5 kg of modified polyolefin and 0.5 kg of polyolefin were dry blended, and 5 kg of pellets obtained by melt mixing were dry blended with 10 g of calcium stearate. When a test piece was prepared and measured in the same manner as in, the results shown in Table 1 were obtained.

[0020]

Example 5 6.5 kg of polyamide and 3.5 of modified polyolefin
10 kg of calcium stearate was dry blended with 5 kg of pellets obtained by dry blending with kg and melt mixing, and a test piece was prepared in the same manner as in Example 1.
Upon measurement, the results shown in Table 1 were obtained.

[0021]

Comparative Example 1 Polyamide 6.5 kg, Modified polyolefin 2.5
kg, 1.0 kg of polyolefin and 50 g of calcium stearate were mixed together, melt-mixed, and the obtained pellets were molded to prepare a test piece, and measurement was performed, and the results shown in Table 2 were obtained. .

[0022]

Comparative Example 2 A test piece was prepared and measured in the same manner as in Example 1 except that calcium stearate was not added.
I got a result like.

[0023]

Comparative Example 3 A test piece was prepared and measured in the same manner as in Example 1 except that 2.5 g of calcium stearate was added to 5 kg of the resin composition, and the results were as shown in Table 2. .

[0024]

Comparative Example 4 A test piece was prepared and measured in the same manner as in Example 1 except that 200 g of calcium stearate was added to 5 kg of the resin composition, and the results were as shown in Table 2.

[0025]

Comparative Example 5 A test piece was prepared and measured in the same manner as in Example 2 except that 5.0 kg of polyamide, 4.0 kg of modified polyolefin and 1.0 kg of polyolefin were dry blended. I got good results.

[0026]

Comparative Example 6 6.5 kg of polyamide and 3.5 k of polyolefin
Test pieces were prepared and measured in the same manner as in Example 2 except that g was dry-blended, and the results shown in Table 2 were obtained.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

EFFECT OF THE INVENTION The polyamide / polyolefin alloy resin composition obtained by the present invention has the characteristics of each resin and has good physical properties such as heat resistance, mechanical strength and slidability, and weld strength, Since the elongation is remarkably improved and the moldability is excellent, it is used as an engineering resin for automobile parts such as radiator tanks, wheel covers, rocker covers, silencers, headlamp reflectors, connectors, relay blocks, junction blocks, fasteners, It is widely used as a motorcycle component, for example, a leg shield, a fender, a meter visor, a side cover, a step, a body cover, a windshield cover, and an electric / electronic component, for example, a connector, a pump housing, and the like.

[Brief description of drawings]

FIG. 1 is a plan view of a test piece mold for measuring strength / elongation of a weld portion used in Examples and Comparative Examples of the present invention.

FIG. 2 is a plan view of an MFD measuring mold used in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

1 ... Weld part 2 ... Sprue 3 ... Runner 4 ... Test piece

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Claims (2)

(57) [Claims] 1. (A) 60 to 90 parts by weight of polyamide,
100 parts by weight of a resin mixture obtained by melt-mixing (B) 10 to 40 parts by weight of a polyolefin partially or entirely modified with an acid anhydride, and (C) calcium stearate
Aluminum, stearate, magnesia stearate
Um, zinc stearate, lithium stearate, stearate
Barium formate, calcium laurate, lauric acid
Barium, zinc laurate, sodium montanate and
And a resin composition comprising 0.1 to 3 parts by weight of one or more higher aliphatic carboxylic acid metal salt selected from calcium montanate. 2. A mixture of (A) 60 to 90 parts by weight of polyamide and (B) 10 to 40 parts by weight of a polyolefin, which is wholly or partially modified with an acid anhydride, is melt-mixed, and then (C) is added to the melt mixture. Calcium stearate, stearic acid
Luminium, magnesium stearate, stearic acid
Zinc, lithium stearate, barium stearate,
Calcium laurate, barium laurate, laurin
Zinc acidate, sodium montanate and calci montanate
A method for producing a resin composition, which comprises mixing 0.1 to 3 parts by weight of one or more higher aliphatic carboxylic acid metal salt selected from um and molding.