JP2000319508A - Polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition combinedly having excellent properties of an aromatic polyamide resin and excellent performances of molding properties, and having more excellent resistance to heat-aging and moisture resistance in comparing to usual aromatic polyamide resin compositions. SOLUTION: This polyamide resin contains (C) 0.01-1 pt.wt. of acopper compound, (D) 0.01-5 pts.wt. of an alkali metal halide compound and (E) 0.05-5 pts.wt. of an organic-based stabilizer to a total of 100 pts.wt. of (A) 95.5-50 pts.wt. of a polyamide resin composed of a dicarboxylic acid component unit comprising an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid and a diamine component unit comprising an aromatic diamine and an aliphatic diamine and having 1.5-5.0 relatice viscosity measured in concentrated sulfuric acid at 20 deg.C and (B) 0.5-50 pts.wt. of a modified polyolefin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyamide resin composition. For more information, while having excellent heat aging resistance,
The present invention relates to a polyamide resin composition which is excellent in mechanical properties, impact resistance, chemical resistance, etc., has low water absorption, and particularly has excellent mechanical properties in moisture resistance.

[0002]

2. Description of the Related Art Conventionally, general-purpose polyamide resins represented by nylon 6 and nylon 66 have excellent mechanical properties,
Due to its properties such as heat resistance, chemical resistance, and abrasion resistance, it has been used in many applications as an engineering plastic. The demand for low water absorption is increasing. In particular, when exposed to high temperatures for a long period of time, such as in automobile parts, thermal degradation and oxidative degradation of the resin become a major problem. The above polyamide resin has a high melting point, but becomes extremely brittle in a short time when exposed to a high temperature of 100 ° C. or more in air. Therefore, when used in applications or fields that require such long-term heat resistance, various methods have been formulated to prevent oxidative deterioration at high temperatures.

[0003] In response to such demands, recently, various aromatic polyamide resins mainly comprising a polyamide composed of terephthalic acid and 1,6-hexanediamine having a higher melting point than conventional polyamide resins have been proposed, and some of them have been put into practical use. Has been However, it is necessary to ensure the long-term thermal stability of this aromatic polyamide resin as well as the conventional polyamide resin. JP-A-61-285252, JP-A-63-105057, and the like have proposed methods for preventing thermal degradation of an aromatic polyamide resin. However, the polyamide resin composed of terephthalic acid and 1,6-hexanediamine has a temperature exceeding the decomposition temperature of the polymer.
Since it has a melting point near 0 ° C., melt polymerization and melt molding are difficult and are not practical.

For this reason, the actual usable temperature range is lowered to about 280 to 320 ° C. by copolymerizing 30 to 40 mol% of a dicarboxylic acid component such as adipic acid or isophthalic acid or an aliphatic polyamide such as nylon 6. At present, it is used in a composition having a melting point. For example, JP-A-59-155426 proposes a crystalline copolyamide formed from an aromatic dicarboxylic acid component unit, an adipic acid component unit and hexamethylenediamine. This polyamide composition for molding is excellent in heat resistance, mechanical properties, chemical physical properties and molding properties as compared with conventional polyamides, but there is a decrease in mechanical properties when absorbing moisture, and the moisture resistance is sufficient. It is hard to say.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides both the excellent properties of an aromatic polyamide resin and the performance of excellent moldability, and also has an advantage over conventional aromatic polyamide resin compositions.
An object of the present invention is to provide a polyamide resin composition having excellent heat aging resistance and moisture resistance.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the dicarboxylic acid component unit is composed of an aromatic dicarboxylic acid component unit and an aliphatic dicarboxylic acid component unit. A composition in which a diamine component unit is used in combination with a polyamide resin having a specific composition consisting of an aromatic diamine component unit and an aliphatic diamine component unit, a modified polyolefin, and a specific type and amount of a stabilizer. The present inventors have found that a polyamide resin having excellent heat aging resistance, low water absorption and particularly improved moisture resistance is provided while maintaining the excellent properties of the resin, and the present invention has finally been completed.

That is, the present invention relates to a polyamide resin wherein [A] the dicarboxylic acid component unit comprises an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and the diamine component unit comprises an aromatic diamine and an aliphatic diamine. Medium 20
For a total of 100 parts by weight of 95.5 to 50 parts by weight of a polyamide resin having a relative viscosity of 1.5 to 5.0 and a 0.5 to 50 parts by weight of [B] modified polyolefin, the
[C] 0.01 to 1 part by weight of a copper compound, [D] 0.01 to 5 parts by weight of an alkali metal halide compound and [E] 0.05 to 5 parts by weight of an organic stabilizer. It is a polyamide resin composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the polyamide resin [A] of the present invention, the dicarboxylic acid component unit (a) comprises an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and the diamine component unit (b) comprises an aromatic diamine and an aliphatic diamine. Consists of

The aromatic dicarboxylic acid component unit in the dicarboxylic acid component unit (a) is preferably a residue of at least one compound selected from the group consisting of terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid. And more preferably a terephthalic acid residue. The aliphatic dicarboxylic acid component unit in the dicarboxylic acid component unit (a) is preferably an aliphatic dicarboxylic acid component unit having 4 to 12 carbon atoms.
Examples of aliphatic dicarboxylic acids used to introduce aliphatic dicarboxylic acid component units include, for example, succinic acid, adipic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, undecane dicarboxylic acid, and dodecane dicarboxylic acid and Examples thereof include dimer acid, and among them, adipic acid is particularly preferable.

In the polyamide resin (A), the aromatic dicarboxylic acid component unit is preferably 30 to 80 mol%, more preferably 40 to 75 mol%, per 100 mol% of the dicarboxylic acid component units. The content of the aliphatic dicarboxylic acid component unit is preferably from 20 to 70 mol%, and preferably from 25 to 60 mol%. When the content of the aromatic dicarboxylic acid component unit, preferably the terephthalic acid component unit, as the dicarboxylic acid component unit is more than 80 mol%, the flexibility is reduced, and the impact resistance and the heat aging resistance are significantly reduced. become. Further, the content of the aromatic dicarboxylic acid component unit, preferably the terephthalic acid component unit, is 3%.
If the content is less than 0 mol%, the crystallinity is greatly reduced, and the heat resistance, water resistance, etc. are significantly reduced, which is not preferable.

In the diamine component unit (b), examples of the aromatic diamine component unit include para-xylylenediamine, meta-xylylenediamine and ortho-xylylenediamine, and preferably meta-xylylenediamine. In the diamine component unit (b), the aliphatic diamine component unit preferably comprises an aliphatic diamine component unit having 6 to 18 carbon atoms. Such an aliphatic diamine component unit may be a linear alkylenediamine component unit,
It may be a branched chain alkylenediamine component unit. Specific examples of such an aliphatic diamine component unit include, for example, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, and 1,10-diaminononane. A component unit derived from a linear alkylenediamine such as diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, and 1,4-diamino-1,1-dimethylbutane, 1,4-diamino -1-ethylbutane,
1,4-diamino-1,2-dimethylbutane, 1,4-
Diamino-1,3-dimethylbutane, 1,4-diamino-1,4-dimethylbutane, 1,4-diamino-2,3
-Dimethylbutane, 1,2-diamino-1-butylethane, 1,6-diamino-2,5-dimethylhexane,
1,6-diamino-2,4-dimethylhexane, 1,6
-Diamino-3,3-dimethylhexane, 1,6-diamino-2,2-dimethylhexane, 1,6-diamino-
2,2,4-trimethylhexane, 1,6-diamino-
2,4,4-trimethylhexane, 1,7-diamino-
2,3-dimethylheptane, 1,7-diamino-2,4
-Dimethylheptane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-2,2-dimethylheptane, 1,8-diamino-1,3-dimethyloctane, 1,8-diamino-1 , 4-dimethyloctane,
1,8-diamino-2,4-dimethyloctane, 1,8
-Diamino-3,4-dimethyloctane, 1,8-diamino-4,5-dimethyloctane, 1,8-diamino-
2,2-dimethyloctane, 1,8-diamino-3,3
From branched chain alkylenediamines such as -dimethyloctane, 1,8-diamino-4,4-dimethyloctane, 1,6-diamino-2,4-diethylhexane, 1,9-diamino-5-methylnonane, etc. There may be mentioned the constituent units derived. Among such linear or branched chain alkylene diamine component units, a linear alkylene diamine component unit is preferable,
In particular, a 1,6-diaminohexane component unit is preferable.

In the present invention, the diamine component unit 100
In the mole%, the aromatic diamine component unit, preferably meta-xylylenediamine component unit, is contained in an amount of preferably 1 to 60 mol%, more preferably 5 to 40 mol%. Aliphatic diamine component unit, preferably having 6 to 6 carbon atoms
18 aliphatic diamine component units, preferably 40 to 9
It is contained in an amount of 9 mol%, preferably 60 to 95 mol%. When the content of the aromatic diamine component unit, preferably the meta-xylylenediamine component unit, as the diamine component unit is more than 60 mol%, the crystallinity is reduced and the heat resistance is greatly reduced. On the other hand, if the content of the aromatic diamine component unit, preferably the meta-xylylenediamine component unit, is less than 1 mol%, the glass transition point temperature is lowered and the water resistance is lowered, which is not preferable.

Regarding the degree of polymerization of the polyamide resin of the present invention, the relative viscosity measured in concentrated sulfuric acid at a temperature of 20 ° C. is 1.5.
-5.0, preferably 2.0-4.0 in terms of mechanical properties. If the relative viscosity is less than 1.5, mechanical properties such as tensile strength and bending strength of the polyamide resin and mechanical properties such as impact resistance will be reduced. When the relative viscosity exceeds 5.0,
When the polyamide resin is made into a final product by injection molding, extrusion molding, blow molding, or the like, it is not preferable because molding processing becomes difficult.

Such a polyamide resin can be produced by using a conventionally known method. Specifically, a polyamide resin can be obtained by melt-polycondensing dicarboxylic acid and diamine or a salt thereof, which are the above-mentioned polyamide constituent units, in the presence or absence of a solvent such as water. Further, a polyamide resin can also be obtained by generating an oligomer by using the above-mentioned melt polycondensation method and then performing polycondensation by using a solid-state polymerization method.

The polyamide resin [A] used in the present invention may optionally contain a terminal blocking agent during or after the polymerization. As the terminal blocking agent, those generally used in polyamide can be added. Specifically, for example, there are monocarboxylic acids, acid anhydrides and the like, and as the monocarboxylic acids, acetic acid, caproic acid, heptanoic acid,
There are octanoic acid, pelargonic acid, stearic acid, lauric acid, benzoic acid and the like, and as the acid anhydride, maleic anhydride, succinic anhydride, glutaric anhydride, phthalic anhydride,
Hexahydrophthalic anhydride and the like can be mentioned, but hexahydrophthalic anhydride is most preferred because the polyamide is not colored and the reactivity of the terminal blocking agent is high. In addition, by adding the terminal blocking agent, it is possible to suppress an increase in the viscosity of the polyamide resin at the time of molding, and to suppress gelation of the polyamide resin at the time of molding by blocking the amino terminal group of the polyamide resin. be able to.

The modified polyolefin [B] used in the present invention includes polyolefins modified by copolymerization with α, β-unsaturated carboxylic acids or their esters or metal salt derivatives, carboxylic acids or acid anhydrides. Polyolefins modified by graft copolymerization or random copolymerization can be used. Specific examples of these polyolefins include polyethylene, polypropylene,
Ethylene / propylene copolymer, ethylene / ethyl acrylate copolymer, ethylene / 1-butene copolymer, ethylene / 4-methyl-1-pentene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene Copolymer, ethylene / 1-decene copolymer, propylene / 1
-Butene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 1-hexene copolymer, propylene / 1-octene copolymer, propylene / 1-decene copolymer, propylene / 1-dodecene Copolymer, ethylene / propylene / 1,4-hexadiene copolymer,
Examples thereof include an ethylene / propylene / dicyclopentadiene copolymer, an ethylene / 1-butene / 1,4-hexadiene copolymer, and an ethylene / 1-butene / 5-ethylidene-2-norbornene copolymer.

Next, specific examples of the [C] copper compound blended in the polyamide resin composition of the present invention include cuprous chloride, cuprous bromide, cuprous iodide, cupric chloride, and the like. Copper salts of organic carboxylic acids such as cupric bromide, cupric iodide, cupric phosphate, cupric pyrophosphate, copper sulfide, copper nitrate, and copper acetate can be used. These copper compounds may be used alone or in combination of two or more. Further, these copper compounds are used in an amount of 0.0 with respect to 100 parts by weight of the total amount of the polyamide resin and the modified polyolefin.
It is 1 to 1 part by weight, preferably 0.02 to 0.5 part by weight.

Specific examples of the alkali metal halide [D] compounded in the polyamide resin composition of the present invention include lithium chloride, lithium bromide, lithium iodide, lithium fluoride, sodium chloride, and sodium iodide. , Potassium chloride, potassium bromide, potassium iodide,
Potassium fluoride and the like can be mentioned. Of these, potassium iodide is particularly preferred. These alkali metal halide compounds may be used alone or in combination of two or more. Further, these alkali metal halide compounds are 0.01 to 5 parts by weight based on 100 parts by weight of the total amount of the polyamide resin and the modified polyolefin,
The amount is preferably 0.02 to 2 parts by weight, and more preferably 100 to 1000 parts by weight based on 100 parts by weight of the copper compound.

Further, specific examples of the [E] organic stabilizer blended in the polyamide resin composition of the present invention include conventionally known phenol stabilizers, amine stabilizers, and the like.
Examples thereof include thioether-based stabilizers and phosphorus-based stabilizers. These organic stabilizers can be used alone or in combination of two or more. Particularly, a combination of a phenol stabilizer and a thioether stabilizer, a phosphorus stabilizer, or an amine stabilizer can be used. The effect is great when used in combination with a thioether-based stabilizer and a phosphorus-based stabilizer. These organic stabilizers are preferably used in an amount of 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the total amount of the polyamide resin and the modified polyolefin.

In the polyamide resin composition of the present invention, various fillers other than those described above can be blended as required in order to improve mechanical strength, physical properties and the like. The filler is a compound such as a powder or a fibrous material.Specifically, a powdery inorganic compound such as silica, alumina, talc, kaolin, quartz, glass, mica, graphite, glass fiber, carbon fiber, ceramic There are fibrous inorganic compounds such as fiber and asbestos fiber, and two or more of these can be used in combination. In addition, these fillers are compounded by a usual method using a kneader, an extruder, or the like.
It can be melt-kneaded and can contain 5 to 150 parts by weight of a filler based on 100 parts by weight of the polyamide resin. When the amount of the filler is less than 5 parts by weight, mechanical properties such as heat deformation temperature and high-temperature rigidity of the polyamide resin composition are reduced, and the reinforcing effect cannot be exhibited. Is hardly improved, and molding workability is deteriorated.

Further, the polyamide resin composition of the present invention comprises:
Heat stabilizers, antioxidants, UV absorbers,
Light stabilizers, plasticizers, lubricants, crystal nucleating agents, antistatic agents, flame retardants, pigments, dyes or other polymers can also be added.

The above-mentioned components in the polyamide resin composition of the present invention may be added at the time of the polycondensation reaction.
Alternatively, a method of dry blending and a method of blending at the time of melt kneading using an extruder may be mentioned.

[0023]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The properties and physical properties shown in the following examples and comparative examples were measured by the following test methods. (1) Water absorption: A test piece having a length of 126 mm, a width of 12.6 mm and a thickness of 1.6 mm was treated for 135 hours in a thermo-hygrostat at 35 ° C. and 95% RH, and the water absorption was determined by the following equation. Water absorption (%) = (weight after 135 hours treatment-initial weight)
/ Initial weight × 100 (2) Heat aging resistance: A JIS No. 2 dumbbell piece in an injection-molded, absolutely dry state is treated in a gear oven at 150 ° C. for 7 days, and then the tensile strength and elongation are measured according to ASTM D-638. did. As an index of heat aging resistance, a retention ratio (%) with respect to tensile strength and elongation before treatment was determined. (3) Flexural strength: measured according to ASTM D-790. (4) Flexural modulus: Measured according to ASTM D-790. (5) Impact strength: measured according to ASTM D-256.

Reference Example 1 10.091 kg of 1,6-diaminohexane, metaxy
1.460 kg of lylenediamine, 9.88 of terephthalic acid
0 kg, adipic acid 5.561 g, and as a catalyst
24 g of sodium phosphite and 12.4 of ion-exchanged water
Charge 99 kg into a 50 L batch type tank,
After elementary substitution, 135 ° C, 2.5 kg / cm ^TwoAnd evenly disturb
Stir and dissolve. Heating pipe (length)
4m, 20mm pipe diameter) at a supply rate of 8L / hr
The liquid is sent, the internal liquid temperature is 240 ° C, and the water vapor
The same pressure as the pressure 35kg / cm^TwoNitrogen bon
It was pressurized with a bee. After that, the evaporator (pressurized reactor)
The reaction mixture is fed, where it is heated to 285 ° C.
5kg / cm^TwoWhile draining while adjusting the pressure to maintain
did. The residence time of this pressurized reactor is about 1 hr.
An oligomer having a relative viscosity of 1.1 to 1.3 in this pressure reactor
was gotten. Then supply this oligomer in the molten state
L / D60 at the amount of 4.7 kg / hr, screw diameter 37m
m twin-screw extruder (barrel set temperature is 300-330 ° C,
Screw rotation speed 100rpm)
Advance. Also, as a terminal blocking agent in the middle of the twin screw extruder
Add hexahydrophthalic anhydride, adjust viscosity,
A polyamide resin having a viscosity of 2.33 was obtained. These polymerizations
The process was performed continuously. Of the obtained polyamide resin
Melting point 298 ℃, glass transition temperature 100 ℃, crystallization
The temperature was 127 ° C.

Example 1 The polyamide resin pellets obtained in Reference Example 1 were
After drying for 5 hours in a hot air drier at 0 ° C., dry-blending a predetermined amount of the modified polyolefin, copper compound, alkali metal halide compound and organic stabilizer shown in Table 2,
Twin screw extruder (screw diameter = 40 mm, L / D = 22,
The mixture was melt-kneaded using a cylinder temperature of 300 to 320 ° C. and a screw rotation speed of 70 rpm, and pelletized.
After the obtained pellets were dried with a hot-air dryer at 100 ° C. for 5 hours, test pieces were molded at a cylinder temperature of 320 ° C. using an injection molding machine (Toshiba Machine Co., Ltd., IS100) and used for evaluation. Table 2 shows the results.

Reference Examples 2 to 4 A polyamide resin was polymerized in the same manner as in Reference Example 1 except that the molar ratio of the dicarboxylic acid component unit and the molar ratio of the diamine component unit were changed as shown in Table 1. . Table 1 shows the polymerization results.

Examples 2 to 4 and Comparative Examples 1 to 2 The polyamide resins obtained in Reference Examples 2 to 4 were modified polyolefins, copper compounds, alkali metal halide compounds and After performing the melt-kneading with the organic stabilizer, a test piece was molded using an injection molding machine, and was used for evaluation. The results are also shown in Table 2.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

As apparent from Table 2, in the polyamide resin composition of the present invention, the dicarboxylic acid component unit is composed of an aromatic dicarboxylic acid component unit and an aliphatic dicarboxylic acid component unit, and the diamine component unit is aromatic. A composition comprising a combination of a polyamide resin having a specific composition, a modified polyolefin and a stabilizer of a specific type and amount, comprising an aromatic diamine component unit and an aliphatic diamine component unit, and comprising a conventional aromatic polyamide resin It is possible to provide a polyamide resin composition which is excellent in heat aging resistance, low in water absorption and particularly improved in moisture resistance while keeping the excellent characteristics of the above. Since the polyamide resin composition of the present invention having such excellent performance can be suitably used for engineering plastic applications such as automotive applications and electric / electronic component applications, it greatly contributes to the industrial world.

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Claims (4)

[Claims] 1. A polyamide resin wherein the dicarboxylic acid component unit comprises an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and the diamine component unit comprises an aromatic diamine and an aliphatic diamine. 95.5 having a relative viscosity of 1.5 to 5.0 as measured by
To 50 parts by weight and [B] modified polyolefin 0.5 to
[C] 0.01 to 1 part by weight of a copper compound, [D] 0.01 to 5 parts by weight of an alkali metal halide compound and [E] an organic stabilizer with respect to 100 parts by weight of 50 parts by weight in total.
A polyamide resin composition containing from 0.5 to 5 parts by weight. 2. The polyamide resin composition according to claim 1, wherein the aromatic diamine component constituting the polyamide resin is xylylenediamine. 3. The polyamide resin according to claim 1, wherein the aromatic dicarboxylic acid component is at least one compound selected from the group consisting of terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid. A polyamide resin composition. 4. The polyamide resin composition according to claim 1, wherein the aliphatic dicarboxylic acid component constituting the polyamide resin has 4 to 12 carbon atoms, and the aliphatic diamine component has 6 to 18 carbon atoms.