JPH05310922A - Aromatic copolyamide - Google Patents

Abstract

PURPOSE:To produce the subject aromatic crystalline copolyamide excellent in heat resistance and capable of melt molding by copolymerizing a prescribed ratio of an alkylene-2,6-naphthalene dicarboxylamide unit and an aminocarboxylic acid unit. CONSTITUTION:After forming a single salt, e.g. from a diamine (e.g. hexamethylene diamine) and 2,6-naphthalenedicarboxylic acid, an aqueous solution is prepared by adding a prescribed amount of an aminocarboxylic acid (a 4 to 12C straight chain lactam or aminocarboxylic acid, preferably epsilon- caprolactam) to the abovementioned salt. The resultant aqueous solution is meltpolymerized while being heated at 100 to 340 deg.C at 0 to 30Kg/cm<2>, thus producing the aromatic crystalline copolyamide composed of repeating units of formulae I and II (R1 and R2 are each a 4 to 12C aliphatic alkylene group) in a molar ratio of (formula I/formula II)=(30/70) to (90/10), preferably (35/65) to (60040), exhibiting 1.5 to 4 relative viscosity (in 96 wt.% concentrated sulfuric acid solution, at 35 deg.C and in a concentration of 1g/dl), excellent in heat resistance, transparency and mechanical properties and capable of melt molding.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel linear semiaromatic copolyamide. More specifically, it relates to a semi-aromatic copolyamide having excellent transparency and capable of being melt-molded.

[0002]

2. Description of the Related Art Aliphatic polyamides such as 6-nylon and 66-nylon are generally used as engineering plastics for various purposes because of their excellent strength, rigidity and abrasion resistance, and their ease of molding. ing.

However, in recent years, its use is limited due to its low heat resistance in fields where heat resistance is more required, such as electronic parts and automobile materials.

On the other hand, an aromatic polyamide obtained from an aliphatic diamine such as hexamethylenediamine and an aromatic dicarboxylic acid component such as terephthalic acid has a high melting point and excellent heat resistance, but cannot be melt-molded. There is a drawback.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a melt-moldable semi-aromatic copolyamide having excellent heat resistance and mechanical properties.

[0006]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present inventors arrived at the present invention as a result of extensive studies. That is, the present invention is

[0007]

[Chemical 2]

And has a molar ratio of (I) / (II) of about 3
It is a crystalline semi-aromatic copolyamide in the range of 0/70 to about 90/10.

The semi-aromatic copolyamide of the present invention will be described in detail below.

The semi-aromatic copolyamide of the present invention is a polyamide formed from an alkylene-2,6-naphthalenedicarboxylamide component unit (I) and an aminocarboxylic acid component unit (II).

Here, the alkylene-2,6-naphthalenedicarboxylamide component unit (I) is composed of a 2,6-naphthalenedicarboxylic acid component and a diamine component as a dicarboxylic acid component unit. The diamine component is selected from linear aliphatic alkylenediamine components having 4 to 12 carbon atoms. Specifically, for example, 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminopephtan, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11 -Diaminoundecane and 1,12-diaminododecane are exemplified. It is a component derived from one or more of these compounds. Among them, 1,6-diaminohexane is particularly preferable.

Further, the aminocarboxylic acid component unit (II) to be copolymerized with the alkylene-2,6-naphthalenedicaboxylamide component unit (I) has a linear carbon number of 4 to 1
It is selected from the group consisting of 2 lactams or aminocarboxylic acids. Specifically, for example, those derived from lactams such as ε-caprolactam and ω-laurolactam; 6-
Aminocaproic acid, 11-aminoundecanoic acid, 12-
Examples thereof include those derived from aminocarboxylic acids such as aminododecanoic acid. A unit derived from one or more of these compounds. Among them, ε-caprolactam is particularly preferable.

The semi-aromatic copolyamide of the present invention is a copolyamide formed from an alkylene-2,6-naphthalenedicaboxylamide component unit (I) and an aminocarboxylic acid component unit (II), A copolymerization ratio of I) / (II) is about 30/70 to about 90/10 in terms of molar ratio,
It is preferably 35/65 to 60/40.

The copolymerization ratio of (I) / (II) is 3 in molar ratio.
If it is less than 0/70, the melting point of the polymer is lowered, and at the same time, the crystallinity of the polymer is lowered, and the heat resistance is lowered, which is not preferable.

When the copolymerization ratio of (I) / (II) is more than 90/10 in terms of molar ratio, the melting point of the polymer becomes high and the heat resistance is improved, but the processing temperature becomes high. It is not preferable because thermal decomposition occurs and melt molding cannot be performed.

Here, the degree of polymerization (intrinsic viscosity) of the semiaromatic polyamide of the present invention is not particularly limited and is usually 96.
% Concentrated sulfuric acid solution (35 ° C.), the relative viscosity (ηrel) at a concentration of 1 g / dl is in the range of 1.5 to 4.0, and there is no particular problem.

The method for producing the semi-aromatic copolyamide of the present invention is not particularly limited, but for example, a single salt is usually prepared from a diamine and 2,6-naphthalenedicarboxylic acid by a predetermined method. Then, a method of melt-polymerizing under pressure of 0 to 30 kg / cm ² while heating an aqueous solution in which a predetermined amount of this salt and aminocarboxylic acids are mixed in a range of 100 to 340 ° C., or a prepolymer by the same operation once. And then solid phase polymerization at a temperature below the melting point,
Alternatively, a method of increasing the degree of polymerization with a melt extruder may be used.

It should be noted that a small amount of aromatic dicarboxylic acid such as aromatic diamine, terephthalic acid, isophthalic acid, and other naphthalenedicarboxylic acid can be copolymerized within a range not impairing the object of the present invention, Additive,
For example, a viscosity modifier, a polymerization catalyst, a heat stabilizer, an oxidative deterioration inhibitor, a coloring inhibitor, a plasticizer and the like may be added before or after the polymerization.

[0019]

The present invention will be described in more detail with reference to the following examples. The measurement of various physical properties is performed by the following methods.

1) Relative viscosity (ηrel) It was measured at a polymer concentration of 1 g / dl at 35 ° C. using a 96% concentrated sulfuric acid solvent.

2) Melting point (Tm), glass transition point (Tg) DSC (PERKIN-ELMER Model DS)
Using C-4), about 10 mg of sample is precisely weighed, heated to 350 ° C. at a heating rate of 20 ° C./min in a nitrogen gas stream, held for 5 minutes, and cooled to 50 ° C. at a cooling rate of 20 ° C./min After that, the temperature was maintained at this temperature for 5 minutes, and then heated again to 350 ° C. at a temperature rising rate of 20 ° C./min.

The peak at the first inflection point at this time was Tg, and the endothermic peak was Tm.

3) Thermal decomposition temperature It was measured using a differential thermogravimetric measuring apparatus (TG-DTA, standard type) manufactured by Rigaku Denki Co., Ltd. About 10
Precisely weigh mg, raise the temperature at 10 ° C / min in a nitrogen gas stream and raise to 5
The wt% weight loss point was measured as the thermal decomposition temperature.

4) Tensile Strength / Elongation at Break Measured according to ASTM D638.

5) Bending Strength / Elastic Modulus Measured according to ASTM D790.

[0026]

Example 1 1168 g (3.5 mol) of hexamethylene ammonium naphthalate (6N salt) consisting of hexamethylenediamine and 2,6-naphthalenedicarboxylic acid and ε
-Caprolactam 325 g (2.9 mol) (6N salt / ε
-Caprolactam = 55/45 molar ratio, total amount 6.4 mol
) Was added with 220 ml of ion-exchanged water, 3.9 g of benzoic acid as a viscosity modifier and 1.0 g of phosphorous acid as a polymerization catalyst.
Was added and stirred, and then charged into an autoclave having a volume of 5 liters. After purging with nitrogen gas, it takes 2 hours for 2 hours.
The temperature inside the autoclave is 25kg /
260 hours for another 2 hours, keeping it under ² cm
Hold at ° C. Then, heating is continued to 300 to 340 ° C. while gradually releasing pressure over 2 hours, and further maintained at this temperature for 15 to 30 minutes to complete the polymerization, followed by cooling,
The polymer was removed from the autoclave.

The obtained polymer was neither colored nor gelled, and a white polymer having a viscosity ηrel = 3.10 was obtained. The melting point (Tm) and glass transition temperature (T
g) and the thermal decomposition temperature were as shown in Table 1.

[0028]

[Table 1]

[0029]

Examples 2 to 4 Polymerization was carried out in the same manner as in Example 1 except that the molar ratio of 6N salt to ε-caprolactam shown in Table 1 was used (total amount 6.4 mol).

A white polymer was obtained which was neither colored nor gelled in any case.

The viscosity of each polymer (ηrel),
The melting point (Tm), glass transition temperature (Tg) and thermal decomposition temperature were as shown in Table 1.

[0032]

Comparative Example 1 1500 g (4.5 mol) of nylon 6 salt,
The procedure of Example 1 was repeated, except that 220 ml of ion-exchanged water, 2.7 g of benzoic acid as a viscosity modifier, and 0.7 g of phosphorous acid as a polymerization catalyst were used. The obtained prepolymer was in a powder form and no evidence of melting was found.

This prepolymer was transferred to a three-necked flask equipped with a stirring blade, and solid phase polymerization was carried out under vacuum in a salt bath at 250 ° C. for 8 hours.

The properties of the obtained polymer are shown in Table 1. It was found that the melting point (Tm) and thermal decomposition temperature of this polymer are extremely close to each other, and ordinary melt molding cannot be performed.

[0035]

Comparative Example 2 The molar ratio of 6N salt and ε-caprolactam is 2
Polymerization was performed in the same manner as in Example 1 except that the total amount was 5/75 (6.4 mol).

The obtained polymer has a viscosity of ηrel =
It was 2.61 transparent.

When various properties of this polymer were measured,
The melting point (Tm) peak did not appear, and it was found to be an amorphous polymer.

[0038]

Examples 5 to 6 The polymers polymerized in Examples 2 to 3 were pulverized and then dried at 100 ° C for 16 hours using a vacuum dryer.

Next, using each of these polymer powders, 25 mm
A test piece was molded by a diameter screw type injection molding machine.
Molding was carried out under the conditions of a mold temperature of 120 ° C and a cylinder temperature of 310 to 340 ° C.

Tensile strength, elongation at break, bending strength, elastic modulus, etc. were determined using the obtained test pieces. The results are shown in Table 2.

[0041]

[Table 2]

As is clear from the above results, the copolyamide composed of a predetermined composition ratio of hexamethylene-2,6-naphthalene dicarboxamide units and caprolactam units has excellent heat resistance and mechanical properties. It can be said that it is a semi-aromatic copolyamide capable of excellent melt molding.

[0043]

The semi-aromatic copolyamide of the present invention has a high melting point and glass transition temperature, is excellent in heat resistance, and is capable of being melt-molded with excellent mechanical properties. It can be widely used as various members such as electronic parts, automobile materials, and mechanical parts.

When used for these purposes, the semi-aromatic copolyamide of the present invention is a reinforcing material such as glass fiber and carbon fiber, a filler, a nucleating agent, a flame retardant, an antioxidant and a heat stabilizer. Additives such as plasticizers, lubricants, release agents and pigments can be added as long as the characteristics are not impaired.

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[Procedure amendment]

[Submission date] January 25, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

FIELD OF THE INVENTION The present invention relates to a novel linear semiaromatic copolyamide. More specifically, it relates to a semi-aromatic copolyamide having excellent heat resistance and capable of being melt-molded.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

[0028]

[Table 1]

Claims (1)

[Claims] 1. A repeating unit of the following formulas (I) and (II): And has a (I) / (II) molar ratio of 30/70 to 90.
A crystalline aromatic copolyamide having excellent heat resistance in the range of / 10.