JP2000204240A - Polyamide resin composition having excellent weld strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition for molding, which has a high weld strength and excellent moldability without sacrifice of mechanical characteristics, heat resistance and resistance to chemicals inherent to a crystalline polyamide resin and which can be employed as a structural part and an electric part of an automobile or bicycle and also as an electric/electronic component without depending on any special molding machine or molding method. SOLUTION: The composition is obtained by compounding 100 pts.wt. of a polyamide resin composed of 95 to 50 wt.% of a crystalline, partially aromatic-copolymerized polyamide resin and/or a crystalline aliphatic polyamide resin, and 5 to 45 wt.% of a polyamide made of xylylenediamine and an aliphatic dicarboxylic acid, and 5 to 200 pts.wt. of an inorganic filler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyamide resin composition having excellent mechanical properties and moldability and excellent strength of a weld portion. These resin compositions are used as molding materials for automobiles and electric / electronic parts.

[0002]

2. Description of the Related Art Filler-reinforced polyamides are widely used as industrial materials because of their high strength and rigidity.
However, reinforced polyamides that use only crystalline polyamide as the resin have low strength in the welded part, so parts with a large number of welded parts in the molded product or parts or products that require a high safety factor in the welded part have a low weld strength. Problems such as breakage or cracking may occur, and furthermore, under high temperature, high humidity, and high load environments, the use of the weld may be severely deteriorated, and the use thereof may be limited. Also,
When a reinforced polyamide composed of only an amorphous polyamide is used, the strength at the weld portion is sufficient, but the molding time is long, so that the use thereof has also been limited.

As a means for solving such a problem, it is known that the use of a copolymer having a low melting point, such as polyamide 6/66, improves the weld strength. The absolute strength of the product is low, and the heat resistance and chemical resistance are reduced. Japanese Patent Application Laid-Open No. 5-112672 proposes a method of adding a specific acicular filler to a thermoplastic resin such as polyamide. However, although the strength of the weld portion is improved to some extent, a so-called base material other than the weld portion is used. It cannot be used for structural parts that require high base metal strength due to insufficient strength. JP-A-7-1499
No. 47 proposes a method of adding silicone rubber to a thermoplastic resin reinforced with a fibrous filler,
Although the weld strength is improved, it causes a decrease in rigidity and heat resistance.

Japanese Patent Application Laid-Open No. 55-62959,
Japanese Patent Publication No. 172643 proposes a method of adding an aromatic polyamide. However, Japanese Patent Application Laid-Open
No. 62959 discloses that in addition to the fact that a large amount of aromatic polyamide is required and an inexpensive composition cannot be obtained,
The purpose is to improve the surface gloss, and there is no description that the weld strength is improved. Also, Japanese Patent Laid-Open No. 6-172
In Japanese Patent No. 643, since the aromatic polyamide is made of an aromatic dicarboxylic acid as a crystalline one, the level of improvement in weld strength is insufficient.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, has high cycle formability, and has calcium chloride resistance even in an environment of high temperature, high humidity and high load. Another object of the present invention is to provide a polyamide resin composition for molding which maintains high weld strength.

[0006]

The present inventors have made intensive studies to solve this problem, and as a result, have found that
The present inventors have found that the object can be achieved by adding a polyamide resin comprising xylylenediamine and an aliphatic dicarboxylic acid, and arrived at the present invention.

More specifically, the present invention provides (A-1) a crystalline partially aromatic copolymerized polyamide resin containing one aromatic monomer component and / or (A-2) a crystalline aliphatic polyamide resin 95 to 55. (B) 5 to 45% by weight of a polyamide resin composed of xylylenediamine and an aliphatic dicarboxylic acid, and 100 parts by weight of a polyamide resin composed of: (C) 5 to 200 parts by weight of an inorganic filler. And a molding polyamide resin composition having excellent strength.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The (A-1) crystalline partially aromatic copolymerized polyamide resin containing one aromatic monomer component used in the present invention refers to an aromatic dicarboxylic acid component such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid. It is a copolyamide containing one group monomer component. Preferably, it contains one aromatic monomer component and has a melting point of 26.
A crystalline partially aromatic copolymerized polyamide resin having a temperature of from 0 ° C to less than 320 ° C, more preferably a crystalline partially aromatic copolymerized polyamide containing one aromatic monomer component and having a melting point of from 290 ° C to less than 316 ° C Resin. (A-
1) Preferred combinations of the crystalline partially aromatic copolymerized polyamide resins containing one aromatic monomer component include equimolar salts of aliphatic diamine and aliphatic dicarboxylic acid,
A crystalline copolyamide comprising an equimolar salt of an aliphatic diamine and an aromatic dicarboxylic acid and / or an aliphatic polyamide-forming monomer.

Here, the aliphatic diamine is a compound having 4 to 12 carbon atoms.
And aliphatic methylene diamines such as tetramethylene diamine, hexamethylene diamine, octamethylene diamine, nonamethylenediamine, undecamethylene diamine, and dodecamethylene diamine. Aliphatic dicarboxylic acids are aliphatic dicarboxylic acids having 6 to 12 carbon atoms, and include adipic acid, heptanedicarboxylic acid, octanedicarboxylic acid, nonanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, and the like. A preferred combination is an equimolar salt of hexamethylenediamine and adipic acid.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like, and a preferred combination is an equimolar salt of hexamethylenediamine and terephthalic acid.

[0011] The aliphatic-forming monomer may have 6 to 6 carbon atoms.
12 aminocarboxylic acids and lactams having 6 to 12 carbon atoms, 6-aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, α-pyrrolidone, ε-caprolactam, laurolactam , Ε-enantholactam and the like,
Aminocaproic acid, 11-aminoundecanoic acid, 12-
Aminododecanoic acid, ε-caprolactam and laurolactam are preferred. The aliphatic polyamide-forming monomer may be used alone or as a mixture of two or more components.

The amounts of these used are 30 to 70% by weight of an equimolar salt of hexamethylenediamine and adipic acid, 70 to 30% by weight of an equimolar salt of hexamethylenediamine and terephthalic acid, and 0 to 15% by weight of an aliphatic polyamide-forming monomer. %, Preferably 35 to 55% by weight of an equimolar salt of hexamethylenediamine and adipic acid, 65 to 45% by weight of an equimolar salt of hexamethylenediamine and terephthalic acid, and 0 to 10% by weight of an aliphatic polyamide-forming monomer. is there.

The (A-2) crystalline aliphatic polyamide resin used in the present invention comprises an aliphatic diamine and an aliphatic dicarboxylic acid, or comprises a lactam or an aminocarboxylic acid, or two or more of these. It is a copolymer.

Here, the aliphatic diamine has 4 to 12 carbon atoms.
And aliphatic methylene diamines such as tetramethylene diamine, hexamethylene diamine, octamethylene diamine, nonamethylenediamine, undecamethylene diamine, and dodecamethylene diamine. Aliphatic dicarboxylic acids are aliphatic dicarboxylic acids having 6 to 12 carbon atoms, and include adipic acid, heptanedicarboxylic acid, octanedicarboxylic acid, nonanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, and the like. A preferred combination is an equimolar salt of hexamethylenediamine and adipic acid.

The lactam is a lactam having 6 to 12 carbon atoms, and the aminocarboxylic acid is an aminocarboxylic acid having 6 to 12 carbon atoms. As a specific example,
6-aminocaproic acid, 7-aminoheptanoic acid, 11-
Aminoundecanoic acid, 12-aminododecanoic acid, α-pyrrolidone, ε-caprolactam, laurolactam, ε-
Enantholactam and the like are mentioned, but 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, ε-caprolactam and laurolactam are preferred.

The polyamide resin (B) comprising xylylenediamine and aliphatic dicarboxylic acid used in the present invention comprises:
It is an equimolar salt with an aliphatic dicarboxylic acid having 6 to 12 carbon atoms containing at least one aromatic diamine component such as meta-xylene diamine and para-xylene diamine. Specific examples of the aliphatic dicarboxylic acid include adipic acid, heptanedicarboxylic acid, octanedicarboxylic acid, nonanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, and the like. A preferred combination of the polyamide resin comprising xylylenediamine and aliphatic dicarboxylic acid is an equimolar salt of metaxylenediamine and adipic acid.

In the present invention, (A-1) a crystalline partially aromatic copolymerized polyamide resin containing one aromatic monomer component and / or (A-2) a crystalline aliphatic polyamide resin, and (B) xylylenediene The mixing ratio of the polyamide resin comprising the amine and the aliphatic dicarboxylic acid is (A-1)
The resin and / or the resin (A-2) is in the range of 95 to 50% by weight, and the resin (B) is in the range of 5 to 50% by weight. Preferably, (A-1) resin and / or (A-2) resin is 9
0 to 60% by weight, (B) 10 to 40% by weight of the resin, and more preferably (A-1) resin and / or (A)
-2) 90 to 70% by weight of resin, (B) 10 to 3 of resin
0% by weight.

If the amount of the polyamide resin component (B) composed of xylylenediamine and aliphatic dicarboxylic acid is larger than the upper limit of the above-mentioned numerical value, crystallization is delayed and high-cycle moldability is impaired.

On the other hand, if the total amount of the polyamide resin component (B) comprising xylylenediamine and aliphatic dicarboxylic acid is less than 5% by weight, the effect of improving the weld strength is small and the object of the present invention cannot be achieved.

The (C) inorganic filler used in the present invention comprises:
Glass fiber and carbon fiber, fibrous inorganic materials such as wollastonite and potassium titanate whisker, montmorillonite, talc, mica, calcium carbonate, silica, clay, glass powder, glass beads, and other inorganic fillers, various organic or high polymers An organic filler such as a powder may be used, but glass fiber or talc is preferably used. More preferably, it is glass fiber. As the fibrous inorganic material, the fiber diameter is 0.01 to 20 μm, preferably 0.03 to 15 μm, and the fiber cut length is 0.5 to 1 μm.
0 mm, preferably 0.7 to 5 mm.

The amount of the inorganic filler (C) used in the present invention is based on 100 parts by weight of the obtained polyamide resin.
The amount is 5 to 200 parts by weight, preferably 10 to 150 parts by weight, more preferably 10 to 100 parts by weight. If the amount is less than 5 parts by weight, the mechanical strength of the polyamide resin is not sufficiently satisfied. When the amount is more than 200 parts by weight, the mechanical strength is sufficiently satisfied, but the moldability and the surface condition tend to be deteriorated, which is not preferable.

In the composition of the present invention, a heat-resistant agent, a weathering agent, a crystal nucleating agent, a crystallization accelerator,
A release agent, an antistatic agent, a flame retardant, a flame retardant auxiliary such as antimony trioxide, and a function imparting agent such as a color pigment can be used.

More specifically, hindered phenols, phosphites, thioethers,
Copper halogenated and the like can be mentioned, and these can be used alone or in combination. Examples of the weathering agent include hindered amines and salicylates, which can be used alone or in combination. As a crystal nucleating agent, talc,
Examples include inorganic fillers such as clay and organic crystal nucleating agents such as fatty acid metal salts, and these can be used alone or in combination. Examples of the crystallization accelerator include low molecular weight polyamides, higher fatty acids, higher fatty acid esters, and higher aliphatic alcohols, and these can be used alone or in combination. Release agents include fatty acid metal salts,
Examples thereof include fatty acid amides and various waxes, which can be used alone or in combination. Examples of the antistatic agent include aliphatic alcohols, aliphatic alcohol esters and higher fatty acid esters, and these can be used alone or in combination. Flame retardants include metal hydroxides such as magnesium hydroxide, phosphorus, ammonium phosphate, ammonium polyphosphate, melamine cyanurate,
Ethylene dimelamine dicyanurate, potassium nitrate, brominated epoxy compound, brominated polycarbonate compound,
Brominated polystyrene compounds, tetrabromobenzyl polyacrylate, polycondensates of tribromophenol, polybromobiphenyl ethers and chlorine-based flame retardants,
They can be used alone or in combination.

Other thermoplastic resin compositions can be added to the resin composition of the present invention as long as the object of the present invention is not impaired. Examples of the thermoplastic resin used in combination are polyethylene, polypropylene, polystyrene, ABS resin, A
Examples include general-purpose resin materials such as S resin and acrylic resin, polycarbonate, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, and other high heat resistant resins. In particular, when polyethylene or polypropylene is used in combination, it is desirable to use those modified with maleic anhydride, a glycidyl group-containing monomer, or the like.

The resin composition of the present invention may be melt-mixed and molded at the stage of blending the respective resin pellets to obtain a final product, or may be melted in advance using a single-screw or twin-screw extruder, a Banbury mixer, or the like. After mixing, the mixture can be subjected to molding. Thus, it can be used for extrusion molding or injection molding.

The composition of the present invention can be used for molded articles such as engines for automobiles and motorcycles, transmissions, differential mechanism parts, electric parts, electric / electronic parts and the like. Specific examples include oil strainers, timing chain covers, rocker covers, timing chain tensioners, thrust washers, power steering tanks, oil level gauges, brake fluid sub tanks, brake master cylinders, brake piston rods, automatic transmission stators, bearing retainers, governor gears. , Sensors and other mechanical components, electrical components such as relay boxes and connectors, and electric and electronic components such as terminal blocks, connectors and relays.

(Examples) The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, the physical property measurement of the polyamide resin composition obtained by the Example and the comparative example was performed as follows. (Evaluation of physical properties) (Evaluation of mechanical properties) Evaluation was performed under the following item conditions. All evaluations were performed in a dry state. (1) Tensile strength: AS 3.2 mm thick
Using a TM1 test piece, the test was performed at a pulling rate of 10 mm / min according to ASTM D638. The test piece was ASTM1
No. 1 test piece was filled with a molten resin and injection-molded so that no weld portion was present. (2) Weld part tensile strength: AS with 3.2 mm thickness
Using a TM1 test piece, the test was performed at a pulling rate of 10 mm / min according to ASTM D638. The test piece was ASTM1
The molten resin was filled from both ends of the test piece at the same flow rate, and injection molding was performed so that a weld portion was formed at the center of the test piece.

(Evaluation of Formability) (3) Gate Sealing Time: Using an ASTM No. 1 dumbbell, the sealing time of a gate having a width of 3 mm and a thickness of 2 mm is determined from the relationship between the weight of an ASTM test piece as a molded product and the pressure holding time. . Specifically, when gradually increasing the dwell time,
The time at which there was no increase in weight was defined as the gate sealing time.

(Evaluation of Environmental Resistance) (4) Calcium chloride resistance: ASTM No. 1 test piece was immersed in water at 80 ° C. for 24 hours as a pretreatment.
Next, after a humidity control treatment in a 90 ° C. 95% Rh constant temperature / humidity bath for 1 hour, a saturated calcium chloride aqueous solution was applied to the weld portion and heat-treated in a 100 ° C. oven for 1 hour. The humidity control treatment and the heat treatment were defined as one cycle, and after the completion of the five cycles, the presence or absence of cracks in the weld was checked with a loupe.

Example 1 95 parts by weight of polyamide 66 (2020B manufactured by Ube Industries, Ltd.) and 5 parts by weight of a polyamide resin composed of meta-xylylenediamine and adipic acid (hereinafter PAMXD6; Reny 6001 manufactured by Mitsubishi Gas Chemical Co., Ltd.) were previously prepared. After uniform mixing, the mixture was kneaded with a twin screw extruder with a 35 mmφ vent set at a barrel temperature of 285 ° C. This kneaded polyamide resin 10
Glass fiber (manufactured by Nippon Electric Glass Co., Ltd .; glass fiber diameter: 11 μm, glass fiber cut length: 3 mm) was fed from the middle of the extruder to 0 part by weight, so that the desired polyamide resin composition was obtained. After preparation, it was pelletized.
Next, the obtained pellets were dried at 110 ° C. under a reduced pressure of 10 torr for 24 hours, and then injection-molded at a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C., and an ASTM No. 1 tensile test piece and a test for ASTM No. 1 weld evaluation. Pieces were made and evaluated. Table 1 shows the obtained results.

Examples 2 to 6 A polyamide resin composition was prepared in the same manner as in Example 1 except that the proportions of polyamide 66 and PAMXD6 were changed as shown in Table 1, and the physical properties thereof were evaluated. The obtained results are shown in Table 1.

Example 7 As a polyamide resin, polyamide 6 (Ube Industries, Ltd.)
Polyamide resin composition was prepared in the same manner as in Example 3 except that the product 1015B) was used, and its physical properties were evaluated. The kneading is performed at a barrel temperature of 270 ° C. and a cylinder temperature of 23.
Injection molding was performed at 0 ° C. and a mold temperature of 80 ° C. The results obtained are shown in Table 1.

Example 8 A polyamide resin composition was prepared in the same manner as in Example 3 except that polyamide 66 / 6T (8023X manufactured by Ube Industries, Ltd.) was used as the polyamide resin, and its physical properties were evaluated. The kneading was performed at a barrel temperature of 320 ° C., and injection molding was performed at a cylinder temperature of 305 ° C. and a mold temperature of 110 ° C. The results obtained are shown in Table 1.

Example 9 A polyamide resin composition was prepared in the same manner as in Example 3 except that polyamide 6/66 (2123B manufactured by Ube Industries, Ltd.) was used as the polyamide resin, and the physical properties thereof were evaluated.
The kneading is performed at a barrel temperature of 285 ° C. and a cylinder temperature of 2
Injection molding was performed at 70 ° C. and a mold temperature of 80 ° C. The results obtained are shown in Table 1.

Example 10 Talc (Talc cup manufactured by Nippon Talc) as an inorganic filler
A polyamide resin composition was prepared in the same manner as in Example 3 except for using, and the physical properties thereof were evaluated. The results obtained are shown in Table 1.

[0036]

[Table 1]

Comparative Example 1 A polyamide resin composition was prepared according to Example 1 without using a polyamide resin comprising xylylenediamine and an aliphatic dicarboxylic acid, and the physical properties thereof were evaluated. The results obtained are shown in Table 2.

Comparative Example 2 A polyamide resin composition was prepared according to Example 7 without using a polyamide resin comprising xylylenediamine and an aliphatic dicarboxylic acid, and the physical properties thereof were evaluated. The results obtained are shown in Table 2.

Comparative Example 3 A polyamide resin composition was prepared according to Example 8 without using a polyamide resin comprising xylylenediamine and an aliphatic dicarboxylic acid, and the physical properties thereof were evaluated. The results obtained are shown in Table 2.

Comparative Example 4 A polyamide resin composition was prepared according to Example 9 without using a polyamide resin comprising xylylenediamine and an aliphatic dicarboxylic acid, and the physical properties thereof were evaluated. The results obtained are shown in Table 2.

Comparative Example 5 A polyamide resin composition was prepared in the same manner as in Example 1 except that the compositions of the polyamide 66 and the polyamide MXD6 were as shown in Table 2, and the physical properties were evaluated. Table 2 shows the results obtained.
It was also described in.

[0042]

[Table 2]

From these results, when the ratio of the resin (B) is small, the effect of improving the weld strength is not exhibited. On the contrary, when the ratio of the resin (B) is large, the solidification in the mold is slow, and the moldability is low. Decrease.

[0044]

Industrial Applicability The polyamide resin composition of the present invention has high weld strength and excellent moldability without impairing the mechanical properties, heat resistance and chemical resistance inherent in crystalline polyamide resins. . For this reason, it can be used as a molding material for structural parts, electric parts, and electric / electronic parts of automobiles and motorcycles without depending on a special molding machine or molding method.

Claims (6)

[Claims] (A-1) 95 to 55% by weight of a crystalline partially aromatic copolymerized polyamide resin containing one aromatic monomer component and / or (A-2) a crystalline aliphatic polyamide resin. B) 5-45% by weight of a polyamide resin comprising xylylenediamine and an aliphatic dicarboxylic acid, and 100% by weight of a polyamide resin comprising: (C) 5-200 parts by weight of an inorganic filler. Molding polyamide resin composition. 2. The method according to claim 1, wherein (A-1) comprises one aromatic monomer component.
The molding polyamide resin composition according to claim 1, comprising a crystalline partially aromatic copolymerized polyamide resin containing a component and having a melting point of 260 ° C or more and less than 320 ° C. (A-1) is an equimolar salt of hexamethylenediamine and adipic acid of 30 to 70% by weight, an equimolar salt of hexamethylenediamine and terephthalic acid of 70 to 30% by weight, and an aliphatic polyamide-forming monomer. 3. The polyamide resin composition for molding according to claim 1, wherein the polyamide resin composition is a crystalline partially aromatic copolymerized polyamide comprising: 4. The strength of a weld portion according to claim 1, wherein (A-2) comprises an aliphatic diamine and an aliphatic dicarboxylic acid as a crystalline aliphatic polyamide resin or a lactam. Excellent molding polyamide resin composition. 5. An aliphatic polyamide-forming monomer comprising 6-
The polyamide resin composition according to claim 3, wherein at least one of aminocaproic acid, ε-caprolactam, 11-aminoundecanoic acid, 12-aminododecanoic acid, and laurolactam is used. 6. The polyamide resin composition for molding according to claim 1, wherein the inorganic filler is glass fiber.