JPH09104750A - Copolyamide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copolyamide which has a heat resistance higher than that of nylon MXD6, has gas barrier properties and low water absorption properties, and is excellent in mechanical properties such as impact strength by selecting a copolyamide comprising two specific kinds of repeating units in a specified ratio. SOLUTION: This copolyamide contains 90mol% or higher repeating units represented by formulas I and II in a molar ratio of the repeating units represented by formula I to those represented by formula II of (15/85)-(60/40).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolyamide having excellent heat resistance, gas barrier properties and mechanical properties, which is useful as a material for films, sheets, containers, fibers and molded articles.

[0002]

2. Description of the Related Art Polyxylylene adipamide, especially polymetaxylylene adipamide (nylon MXD6), is a molding material, a fiber or a packaging material utilizing low water absorption, excellent mechanical performance, gas barrier property and heat resistance. It is used as a material.

However, these adipamides are required to have higher heat resistance and gas barrier properties depending on the use.
In addition, it is slightly inferior in impact resistance to other polyamides.

On the other hand, Japanese Patent Publication No. 48-28009 proposes to use a copolyamide composed of a xylylene-2,6-naphthalene dicarboxamide unit and a xylylene adipamide unit as a crimpable conjugate fiber. However, the naphthalene dicarboxamide unit is 1 to 15mo
Only 1% was used, and only physical properties as a crimpable conjugate fiber are shown.

[0005]

In view of the above-mentioned problems of the prior art, the object of the present invention is to improve the heat resistance of nylon MXD6.
Another object of the present invention is to provide a copolyamide which can be further improved and has a low water absorption rate and excellent mechanical properties such as gas barrier properties and impact resistance.

[0006]

[Means for Solving the Problems] As a result of intensive studies conducted by the present inventors in order to achieve the above-mentioned object, nylon MXD6
In addition to the adipic acid component as the dicarboxylic acid component of 2,6
The present invention has been accomplished by finding that by introducing a naphthalenedicarboxylic acid component to raise the glass transition temperature, the heat resistance can be increased, the water absorption rate can be lowered, and the impact resistance and the water vapor barrier property can be improved.

That is, in the present invention, 90 mol% or more of the repeating units are represented by the following formulas (1) and (2),
The molar ratio of the repeating unit represented by the formula (1) to the repeating unit represented by the formula (2) [(1) formula / (2) formula] is 15
It is a copolyamide characterized by being in the range of / 85 to 60/40.

Embedded image

Embedded image

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the copolyamide of the present invention, the dicarboxylic acid component is composed of adipic acid units and 2,6-naphthalenedicarboxylic acid units, and the diamine component is metaxylylenediamine or / and paraxylylenediamine units. Consists of.

In the present invention, in order to improve heat resistance and mechanical properties, 9 of the repeating units constituting the copolyamide is used.
0 mol% or more of xylylene-2,6 represented by the formula (1)
-It is necessary to be composed of a naphthalene dicarboxamide unit and a xylylene adipamide unit represented by the formula (2).

When 10 mol% or more of the repeating units constituting the copolyamide are constituted by repeating units other than the xylylene-2,6-naphthalene dicarboxamide unit and the xylylene adipamide unit, heat resistance,
The gas barrier property and mechanical performance are lower than those of nylon MXD6, and the object of the present invention cannot be achieved.

In order to enhance the performance of the copolyamide of the present invention, xylylene-2,6-
Molar ratio of naphthalene dicarboxamide unit and xylylene adipamide unit represented by formula (2) [(1) formula /
It is necessary that the expression (2)] is within the range of 15/85 to 60/40. If the number of xylylene-2,6-naphthalenedicarboxamide units is less than this, improvement of the glass transition temperature is insufficient. If the amount of xylylene-2,6-naphthalenedicarboxamide units is larger than this, the melting point will be high and the moldability will be poor.

The copolymerized polyamide is xylylene-based so long as it does not exceed 10 mol% of the repeating units constituting the copolymerized polyamide.
Repeating units other than 2,6-naphthalene dicarboxamide units and xylylene adipamide units can be introduced. As the diamine component constituting this repeating unit, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 2,4,4-Trimethylhexamethylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane and the like can be mentioned. As the dicarboxylic acid component, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, eicosandicarboxylic acid, terephthalic acid, isophthalic acid. Acid, isomers of naphthalenedicarboxylic acid, 1,4
-Cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and the like can be mentioned.

Examples of the xylylenediamine component used in the polyamide of the present invention include metaxylylenediamine, paraxylylenediamine or a mixture of metaxylylenediamine and paraxylylenediamine.

The method for producing the polyamide of the present invention is not particularly limited, and conventionally known methods can be applied.
An example of the method for producing the polyamide of the present invention is shown below.

A dicarboxylic acid component mainly composed of 2,6-naphthalenedicarboxylic acid and adipic acid, a diamine component mainly composed of xylylenediamine, and water are heated to a temperature at which an amidation reaction occurs in an autoclave, It is kept under pressure of steam for a predetermined time to allow the amidation reaction to proceed. Next, the exhaust valve is opened to release water vapor, and the internal temperature is raised to the melting point of polyamide or higher while returning to normal pressure. After holding for a predetermined time, the polyamide is taken out. Instead of adding the diamine component and the aliphatic dicarboxylic acid component individually, they may be added in the form of nylon salt. A part or all of the dicarboxylic acid component may be used in the form of the corresponding lower alkyl ester.

When it is necessary to increase the molecular weight of the polyamide, the polyamide obtained by melt polymerization can be subjected to solid phase polymerization to increase the molecular weight.

The molecular weight of the polyamide of the present invention thus obtained is not particularly limited, but 1 g at 25 ° C.
It is preferable that the relative viscosity (η _r ) of a 96% concentrated sulfuric acid solution having a concentration of / dl is 1.2 to 5.0.

The copolyamide of the present invention is excellent in heat resistance, gas barrier properties and mechanical properties,
It can be used as a material for sheets, containers, fibers and molded products.

[0019]

EXAMPLES Examples will be shown below, but the present invention is not limited to the following examples. In the following examples, the physical properties of polymers and the like were measured by the following methods. (1) Logarithmic viscosity The relative viscosity (η _r ) of polyamide was determined by using a Canon Fenske viscometer at 25 ° C. in a 96% sulfuric acid solution of 1 g / dl. (2) Glass transition temperature and melting point Polymer glass transition temperature (Tg) and melting point (Tm)
Is a differential scanning calorimeter (DSC) DSC- manufactured by Seiko Denshi.
Using a 200 type, about 10 mg of a sample was placed in a non-sealed container made of aluminum, and measurement was performed in a nitrogen gas (30 ml / min) gas stream at a temperature rising rate of 10 ° C./min.

The physical properties of the film were measured by the following methods. (1) Oxygen Permeability Coefficient According to ASTM D3985. Oxygen permeability measuring device used: Modern Controls, model: OX-TR
AN 10 / 50A, measurement condition: 23 ° C, relative humidity 60
% (2) Moisture Permeability According to JIS Z 0208. Measurement conditions: 40 ° C, 90% relative humidity (3) Impact drilling strength Film impact tester IFT manufactured by Tohoku Seimitsu Co., Ltd.
It was measured using -60 (penetration shape: 25.4 mm hemisphere). Measurement conditions: 23 ° C., relative humidity 50% Sample: 100 μm thick film (4) Tensile physical properties According to ASTM D882. (5) Equilibrium water absorption rate The water absorption rate at the time of equilibrium was determined from the change in the weight of a sample whose water content was dried to 0.1% or less. Measurement conditions: 23 ° C, relative humidity 50%, sample: 50 mm x 50 mm x 0.
03mm sheet

The physical properties of the molded product were measured by the following methods. (1) Tensile physical properties According to ASTM D638. (2) Izod impact value According to ASTM D256. (3) Deflection temperature under load According to ASTM D648. The load was 1820 kPa.

Example 1 (1) Polymer Synthesis 539 g (3.688) of adipic acid (hereinafter abbreviated as AA)
mol) and 2,6-naphthalenedicarboxylic acid (hereinafter, N
DCA) 199 g (0.922 mol) (AA /
(NDCA = 80/20 molar ratio) was charged into a 3 liter stainless separable flask equipped with a stirrer, a partial condenser and a dropping funnel, and the temperature was raised. After the adipic acid was melted, metaxylylenediamine 6 was added while stirring the contents.
28 g (4.610 mol) was continuously added dropwise. The time required for dropping was 1 hour. During this time, the internal temperature is 245
The temperature was continuously raised to ° C. Water distilled along with the addition of meta-xylylenediamine was removed from the reaction system through the partial condenser and the cooler. Subsequently, the internal temperature was raised to 280 ° C. The reaction was further continued at 280 ° C., and when the viscosity of the contents became high to some extent, the contents were cooled and the polymer was taken out.
The obtained polymer was pulverized and then dried using a vacuum dryer.

(2) Preparation of film Next, the obtained polymer was used in a single screw extruder (screw diameter: 20 mmφ, L / D: 25, screw type: full flight) and a cylinder temperature of 24 by T-die method.
5 to 265 ° C., T die temperature of 260 ° C., screw rotation speed of 50 to 70 rpm, thickness of about 0.03 to 0.4
mm of film was obtained. Table 1 shows the measurement results of physical properties and the like.

Example 2 A polymer was obtained in the same manner as in (1) of Example 1 except that the molar ratio of AA to NDCA was 70/30. The obtained polymer is a single screw extruder (screw diameter: 20 mmφ,
L / D: 25, screw type: full flight), cylinder temperature of 250 to 275 ° C. by T-die method,
T-die temperature 270 ° C, screw rotation speed 50-70 rp
A film having a thickness of about 0.03 to 0.4 mm was obtained under the condition of m. Table 1 shows the measurement results of physical properties and the like. Since the obtained polymer is amorphous, it has no melting point (Tm).

Example 3 A polymer was obtained in the same manner as in Example 1 (1) except that the molar ratio of AA to NDCA was 60/40. The obtained polymer is a single screw extruder (screw diameter: 20 mmφ,
L / D: 25, screw type: full flight), cylinder temperature of 260 to 290 ° C. by T-die method,
T-die temperature 285 ° C, screw rotation speed 30-60 rp
A film having a thickness of about 0.03 to 0.4 mm was obtained under the condition of m. Table 1 shows the measurement results of physical properties and the like.

Comparative Example 1 Nylon MXD6 (MX Nylon 6007 manufactured by Mitsubishi Gas Chemical Co., Inc.) was used as a single screw extruder (screw diameter: 20 mmφ,
L / D: 25, screw type: full flight), cylinder temperature of 265 to 275 ° C. by T die method,
T-die temperature 270 ° C, screw rotation speed 50-70 rp
A film having a thickness of about 0.03 to 0.4 mm was obtained under the condition of m. Table 1 shows the measurement results of the physical properties of the polymer and the obtained film.

[0027]

[Table 1] ──────────────────────────────────── Example 1 Example 2 Example 3 Comparison Example 1 ──────────────────────────────────── AA / NDCA AA / NDCA AA / NDCA AA / NDCA Copolyamide composition 80/20 70/30 60/40 100/0 ──────────────────────────────────── ─ η _r 2.4 2.5 2.3 2.7 Tg (℃) 105 116 124 88 Tm (℃) 212 None 269 239 Oxygen permeability coefficient 0.10 0.10 0.12 0.11 (cc ・ mm / m ² / 24h ・ atm) Moisture permeability coefficient 1.37 1.22 0.89 1.45 ( g ・ mm / cm ²・ 24h) Impact drilling strength (J) 0.20 0.21 0.23 0.16 Tensile strength (MPa) 100 92 85 85 Tensile modulus (GPa) 3.0 2.7 2.8 3.2 Tensile elongation (%) 4.4 4.4 5.1 3.3 Equilibrium water absorption rate (%) 3.3 3.4 2.9 3.8 ─────────────────────────────────────

Example 4 AA and NDC synthesized by the same operation as in (1) of Example 1
A screw type injection molding machine (screw diameter: 32 mmφ, mold clamping force: using a polymer having a molar ratio of A of 80/20)
A test piece was molded with 100 Ton). Molding was performed under the conditions of a cylinder temperature of 255 ° C. and a mold temperature of 40 ° C. The obtained test piece was heat-treated at 160 ° C. to crystallize and the physical properties were measured. The results of measuring the physical properties of the molded pieces are shown in Table 2.

Comparative Example 2 Nylon MXD6 [MX Nylon 6001 manufactured by Mitsubishi Gas Chemical Co., Inc.] was used to mold a test piece with a screw injection molding machine (screw diameter: 32 mmφ, mold clamping force: 100 Ton). Molding was performed under the conditions of a cylinder temperature of 250 ° C. and a mold temperature of 40 ° C. The obtained test piece was heat-treated at 150 ° C. to crystallize and the physical properties were measured. Table 2 shows the results of measuring the physical properties of the molded pieces.

[0030]

[Table 2] ─────────────────────────── Example 4 Comparative Example 2 ───────────── ────────────── AA / NDCA AA / NDCA Copolyamide composition 80/20 100/0 ────────────────────── ────── Tensile modulus (GPa) 5.0 5.1 Tensile strength (MPa) 101 121 Tensile elongation (%) 2.6 2.7 Izod impact value (J / m) 53 33 Deflection temperature under load (℃) 115 100 ──── ───────────────────────

As is clear from the above results, the copolyamide composed of the xylylene-2,6-naphthalene dicarboxamide unit and the xylylene adipamide unit has a low water absorption rate, heat resistance, gas barrier property and A polyamide with excellent mechanical properties such as impact resistance.

[0032]

The copolymerized polyamide of the present invention has a low water absorption rate and excellent mechanical properties such as heat resistance, gas barrier property and impact resistance, and is useful as a material for films, sheets, containers, fibers, molded articles and the like. is there.

Claims (1)

[Claims] 1. 90 mol% or more of the repeating unit is represented by the following formulas (1) and (2), and the molar ratio of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) [ (1) / (2)] is 15/85 to 60/4
A copolymerized polyamide characterized by being in the range of 0. Embedded image Embedded image