JPH0643552B2 - Polyamide composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is a biaxial fiber which can be easily produced commercially and has a high gas barrier property as well as a large hot water shrinkage ratio, suppleness, transparency and the like. It relates to a polyamide composition suitable for a stretched film.

[Conventional technology]

Compared to the case where biaxially stretched film is used with aliphatic polyamide such as polycaproamide (nylon 6) and polyhexamethylene adipamide (nylon 6.6), semi-aromatic polyamide is formed with aliphatic polyamide forming unit as the main component. It is known that a biaxially stretched film of a copolyamide containing units has a large gas barrier property and a hot water shrinkage ratio and has a great commercial utility value.

However, in order to increase the gas barrier property in such a copolyamide film, when the co-polymerization ratio of the semi-aromatic component is increased, the flexibility of the film is lost and the transparency is also impaired.

That is, in a biaxially stretched film of a copolyamide containing a semiaromatic polyamide forming unit as a main component and a semiaromatic polyamide forming unit as a main component, the content of the semiaromatic component was limited to a certain ratio or less. . Due to such a situation, the polyamide biaxially stretched film has not yet satisfied all the required performances such as high gas barrier property and large hot water shrinkage, suppleness, and transparency.

[Object of the Invention]

The present inventors have conducted extensive studies to develop a biaxially stretched film having a high gas barrier property and at the same time excellent stretch workability, large hot water shrinkage, flexibility, transparency, etc. The present invention has been accomplished by finding a polyamide composition suitable for a stretched polyamide film.

[Structure of Invention]

That is, the gist of the present invention is to contain 75 to 99% by weight of an aliphatic polyamide forming unit and 25 to 1% by weight of a semi-aromatic polyamide forming unit consisting of one or more aliphatic diamines and one or more aromatic dicarboxylic acids. 100% to 85% by weight of a copolymerized polyamide (component A), a semiaromatic polyamide forming unit consisting of an aliphatic diamine and isophthalic acid and / or terephthalic acid, and an aliphatic polyamide forming unit of 0 to 15% by weight. Polyamide (component B)
And a polyamide composition comprising

Hereinafter, the present invention will be described in detail.

The copolymerized polyamide (A) constituting the biaxially stretched polyamide film of the present invention contains at least one type of aliphatic polyamide forming unit as a main component. Here, the aliphatic polyamide is, for example, a polyamide composed of a lactam or an aliphatic diamine and an aliphatic dicarboxylic acid. The lactam that can be used in the present invention is specifically a lactam having 6 to 12 carbon atoms, and examples thereof include caprolactam, enanthlactam, lauryllactam and the like.

Specific examples of the aliphatic diamine that can be used in the present invention include ethylenediamine, propylenediamine, butylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undeca. Methylenediamine, dodecamethylenediamine, 2
And / or 3-methylhexamethylenediamine, 2,
2,4- and / or 2,4,4-trimethylhexamethylenediamine and the like.

Specific examples of the aliphatic dicarboxylic acid that can be used in the present invention include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, 2 and / or 3-methyladipine. An acid or the like.

Furthermore, the copolymerized polyamide (A) contains one or more so-called semi-aromatic polyamide forming units.

Here, the semi-aromatic polyamide is a polyamide composed of an aliphatic diamine and an aromatic dicarboxylic acid.

As the aliphatic diamine that can be used in the present invention, the same ones as described above are used.

Specific examples of the aromatic dicarboxylic acid that can be used in the present invention include terephthalic acid, isophthalic acid, and those in which the benzene ring of these acids is substituted with an alkyl group having 1 to 6 carbon atoms or a halogen group. .

In the component (A) of the present invention, the content of the aliphatic polyamide forming unit needs to be 75 to 99% by weight, more preferably 80 to 98% by weight. That is, when the aliphatic polyamide forming unit is less than 75% by weight, the flexibility of the film is insufficient when mixed with the component (B) in any proportion.
On the other hand, if it exceeds 99% by weight, even if it is mixed with the component (B) in any ratio, the workability of stretching is poor and there is a problem in practical use, especially when the inflation molding method is used.

The polyamide (B) constituting the polyamide composition of the present invention contains a semi-aromatic polyamide forming unit composed of an aliphatic diamine and isophthalic acid and / or terephthalic acid as a main component.

When using isophthalic acid and terephthalic acid together,
It can be used in any ratio, but is preferably isophthalic acid: terephthalic acid = 80: 20 to 20:80.

Specifically as the aliphatic diamine that can be used in the present invention,
The same as that used for the component (A) is used, but hexamethylenediamine is most preferable.

Further, the polyamide (B) may contain one or more aliphatic polyamide forming units, if necessary.

Here, the aliphatic polyamide is a polyamide composed of a lactam or an aliphatic diamine and an aliphatic dicarboxylic acid. The lactam that can be used in the present invention is specifically a lactam having 6 to 12 carbon atoms, and examples thereof include caprolactam, enanthlactam, lauryllactam and the like.

Specific examples of the aliphatic diamine that can be used in the present invention include ethylenediamine, propylenediamine, butylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undeca. Methylenediamine, dodecamethylenediamine, 2
And / or 3-methylhexamethylenediamine, 2,
2,4- and / or 2,4,4-trimethylhexamethylenediamine and the like.

Specific examples of the aliphatic dicarboxylic acid that can be used in the present invention include succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, undecanedioic acid, 2 and / or 3-methyladipine. An acid or the like.

In the component (B) of the present invention, it is necessary that the content of the semiaromatic polyamide forming unit from the aliphatic diamine and isophthalic acid and / or terephthalic acid is 85% by weight or more. That is, if it is less than 85% by weight, the gas barrier property is deteriorated even when mixed with the component (A) in any ratio.

The polyamides of the component (A) and the component (B) of the present invention are each manufactured by the methods described below. That is, a nylon salt or an aqueous solution of lactam and / or diamine and dicarboxylic acid is formed. This was placed in an autoclave, and a monocarboxylic acid or monoamine and a so-called monofunctional compound were allowed to exist in order to control the degree of polymerization as necessary, and then at atmospheric pressure or higher pressure at 250 ° C. or higher and gradually releasing pressure. Allow polycondensation.

Next, the copolymerized polyamide (A) and the polyamide (B) can be mixed in any proportion to obtain a biaxially stretched film having a high gas barrier property, but in particular, in order to obtain a film having a large hot water shrinkage ratio, (A The component (A) is 95 to 40% by weight, particularly preferably 90 to 70% by weight, based on the total amount of the components () and (B).

The mixing method of the components (A) and (B) of the present invention is usually a method of thoroughly mixing the respective chips or a method of melting and kneading the chips one or more times with a pressing machine or the like, but is not particularly limited to these. Not something.

Copolyamide (A) or polyamide (B) as required
When polymerizing, a heat stabilizer, a surfactant, a defoaming agent, an antioxidant, an antiblocking agent, a lubricant, a pigment and the like can be added. Similarly, when mixing the components (A) and (B),
Alternatively, these additives may be blended in the film forming process.

The polyamide composition of the present invention can be suitably used as a film uniaxially or biaxially stretched.

Molding of the film is usually plasticized by an inflation method or a T-die method at a molding temperature higher than the melting point of either the copolyamide (A) or the polyamide (B),
The film extruded from the die is usually rapidly cooled to a temperature of 80 ° C. or lower to obtain an unstretched film.

In order to obtain a biaxially stretched film sequentially, a method in which an unstretched film extruded from a T-die is longitudinally stretched by a casting roll, and then transversely stretched in a tenter is used. In the case of simultaneous biaxial stretching, a tenter method, a tumbler method or the like is used. The unstretched film may be moisture-conditioned or dried when it is transferred to the stretching step.

If the stretching temperature exceeds 120 ° C, the workability is poor and the stretching temperature is 120 ° C.
It is necessary that the temperature is below, but more preferably 90 to 60 ° C.

When the stretching speed is less than 10,000% / sec, the shrinkage rate is lowered, so 10,000% / sec or more is necessary, but more preferably 20,000% / sec or more.

When the draw ratio is less than 2.0 × 2.0, the shrinkage rate is lowered, so 2.0 × 2.0 or more is necessary, but it is preferably 2.5 × 2.5 or more.

The biaxially stretched film is heat-set at 60 to 150 ° C., more preferably 70 to 120 ° C. for 0 to 180 seconds, more preferably 30 to 90 seconds, and then cooled to 60 ° C. or less.

The biaxially stretched polyamide film obtained by the present invention is excellent in transparency, mechanical properties, heat resistance, cold resistance, and oil resistance, but is mainly composed of a conventionally known aliphatic polyamide forming unit which is not melt mixed. As, as compared with a biaxially stretched film of a copolyamide containing a semi-aromatic polyamide forming unit, it is characterized by a large gas barrier property,
In addition, hot water shrinkage at a relatively low temperature, suppleness,
It is also excellent in transparency and has great practical value.

In addition, the biaxially stretched polyamide film of the composition of the present invention may have a multilayered polyolefin (polyethylene, polypropylene, ethylene-vinyl acetate copolymer and saponified product thereof) or modified polyolefin or polyester on at least one surface thereof, if necessary. It is clear that you can do it.

〔Example〕

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

The measurement items in the examples were carried out by the following methods.

(1) η _{rel It} was determined from the ratio of the number of seconds dropped by the Ostwald viscometer at 25 ° C. of the solution prepared by dissolving 1% by weight of the polymer in 98% sulfuric acid solution divided by the number of seconds the solvent was dropped.

(2) Oxygen permeation amount According to JIS Z-1707, it was measured under the conditions of 23 ° C. and 100% RH.

(3) Haze Measured according to JIS K-6714.

(4) Tensile elastic modulus Measured according to JIS K-6781.

(5) Hot water shrinkage rate A 5 cm x 5 cm square was marked on the stretched film, the film was soaked in a water bath controlled at 75 ° C for 7 minutes, and then the film was taken out. Calculate ΔL The hot water shrinkage ratio was determined by.

Example 1 <Production of (A) Component Copolyamide> To 50 kg of distilled water, 45 kg of caprolactam, 3.0 kg of hexamethylenediamine aqueous solution (80 wt%) and 3.4 kg of terephthalic acid were added and then charged into an autoclave. 2.5 kg
Keeping the pressure of / cm ² while distilling water until the concentration of nylon salt reaches 90%, then pressurize to 13Kg / cm ² while heating and evaporate the water further to reach the internal temperature of 250 ° C. If so, the internal pressure was slowly released, and finally, vacuum polymerization was carried out at a reduced pressure of 700 torr for 40 minutes, followed by extrusion to form a chip. The polymer thus obtained had a weight ratio of aliphatic polyamide-forming units to semi-aromatic polyamide-forming units of 90:10 and η _rel = 3.12.

<Production of Component (B) Polyamide> 53 Kg of distilled water and an aqueous solution of hexamethylenediamine (80 wt.
%) / 13.9 Kg, isophthalic acid 9.8 Kg, and terephthalic acid 4.9 Kg are added and uniformly dissolved with stirring. Water was distilled until the concentration of the nylon salt reached 90 wt% while maintaining a pressure of 2.5 kg / cm ² , and then the pressure was raised to 13 kg / cm ² while heating, and then water was further distilled to bring the internal temperature to 250. When the temperature reached ℃, the internal pressure was released slowly, and finally, the polymerization was carried out under reduced pressure of 700 torr for 1 hour under reduced pressure, followed by extrusion into a chip. The polymer thus obtained had a weight ratio of semi-aromatic polyamide forming units to aliphatic polyamide forming units of 100: 0 and η _rel 2.2.

<Mixing of component (A) and component (B) and film formation> (A) component copolyamide 8 obtained as described above
After mixing 0 parts by weight and 20 parts by weight of the component (B) polyamide in a chip shape with a V-type tumbler, an unstretched film was obtained by using a circular die and extruding at a barrel temperature of 260 ° C and a die temperature of 280 ° C. The film was heated to 80 ° C., stretched by an inflation method, and then heat-set at 70 ° C. for 30 seconds to obtain a film having a thickness of 25 μm. The oxygen transmission rate, Haze, tensile modulus and hot water shrinkage of this film are shown in Table 1, and a biaxially stretched film having a high gas barrier property and at the same time having other good properties was obtained.

Example 2 Except that 70 parts by weight of the component (A) copolymerized polyamide obtained in Example 1 and 30 parts by weight of the (B) component polyamide were mixed,
A film was formed in the same manner as in Example 1. The oxygen permeability, Haze, tensile modulus, and hot water shrinkage of the film are shown in Table-1.
And has a high gas barrier property,
A biaxially stretched film having other good properties was obtained.

Comparative Example 1 The component (A) copolymerized polyamide obtained in Example 1 was formed into a film by the same operation as in Example 1. The oxygen permeation amount of the film was as shown in Table 1 and the gas barrier property was insufficient.

Comparative Example 2 70 parts of the component (A) component copolyamide obtained in Example 1 and 30 parts of nylon 6 (1020CA manufactured by Mitsubishi Kasei Co., Ltd.) were mixed and filmed in the same manner as in Example 1. The oxygen permeation amount of this film was as shown in Table 1 and the gas barrier property was insufficient.

Comparative Example 3 80 parts of nylon 6 (1020 CA manufactured by Mitsubishi Kasei Co., Ltd.) and 20 parts of the component (B) component polyamide obtained in Example 1 were used in Example 1
When the film was mixed and formed into a film by the same operation as in (1), the film was frequently broken during stretching, and a uniform film could not be obtained.

Comparative Example 4 <Production of (A) Component Copolyamide> In the production method of the (A) component copolyamide of Example 1, 30 kg of caprolactam, 12 kg of hexamethylenediamine aqueous solution (80 wt%), and 13.6 kg of terephthalic acid are used. Except for the above, a copolyamide was obtained in the same manner as in Example 1. The weight ratio of the aliphatic polyamide forming unit to the semiaromatic polyamide forming unit of this polymer was 70:30, and η _rel = 3.08.

<Mixing of component (A) and component (B) and film formation> Copolymerized polyamide 8 of component (A) obtained as described above
0 parts by weight and (B) component polyamide 2 obtained in Example 1
When 0 parts by weight was mixed and filmized in the same manner as in Example 1, the gas barrier property was excellent as shown in Table 1, but the tensile modulus was MD 26,000 Kg / cm ² , TD24,300.
The film was as high as Kg / cm ² , and the film was very hard and not practical.

Example 3 <Production of (A) Component Copolyamide> In the production method of the (A) component copolyamide of Example 1, 42.5 kg of caprotacticum, 4.5 kg of hexamethylenediamine (80 wt% aqueous solution), and isophthalic acid of 5. A copolyamide was obtained in the same manner as in Example 1 except that 1 kg was used. The weight ratio of the aliphatic polyamide forming unit to the semi-aromatic polyamide forming unit of this polymer was 85:15, and η _rel = 3.11.

<Production of component (B) copolyamide> Hexamethylenediamine (80 wt%) 1 in 53 kg of distilled water
3.9 kg, isophthalic acid 9.8 kg, terephthalic acid 4.9
After adding Kg and stirring and dissolving uniformly, caprolactam 2.5
Kg was added, and 40 g of acetic acid was further added. Subsequent operations were performed in the same manner as in the method for producing the component (B) copolyamide of Example 1 to obtain the component (B) copolyamide. The weight ratio of the semi-aromatic polyamide forming unit to the aliphatic polyamide forming unit of this polymer was 90:10, and η _rel = 2.07.

<Mixing of component (A) and component (B) and film formation> (A) component copolyamide 8 obtained as described above
5 parts by weight and 15 parts by weight of the component (B) copolyamide were mixed and filmed in the same manner as in Example 1. The oxygen transmission rate, Haze, tensile modulus and hot water shrinkage of this film are shown in Table-
As shown in Fig. 1, a biaxially stretched film having a high gas barrier property and good other properties was obtained.

Comparative Example 5 <Production of (B) Component Copolyamide> In the production method of the (B) component copolyamide of Example 3, the same operation as in Example 3 was performed except that the amount of caprolactam added was 5.0 kg ( Component (B) copolyamide was obtained.
The weight ratio of the semi-aromatic polyamide forming unit to the aliphatic polyamide forming unit of this polymer was 80:20, and η _rel
= 2.01.

<Mixing of component (A) and component (B) and film formation> 85 parts by weight of the component (A) component copolyamide obtained in Example 3 and the component (B) component copolyamide 15 obtained as described above Parts by weight were mixed and filmed in the same manner as in Example 1. The oxygen permeation amount of this film was as shown in Table 1 and the gas barrier property was insufficient.

[Effect of the Invention] In the biaxially stretched film produced by the composition of the present invention,
Semi-aromatic components can be included to the extent not possible with the prior art. Therefore, it has a high gas barrier property, and when used for food packaging and the like, it tends to be preferable for the storage of contents. In addition, the hot water shrinkage rate of the conventional copolyamide having caproamide as the main component at a relatively low temperature was insufficient and the adhesion to the contents at the time of shrinkage was poor, whereas the composition of the present invention The biaxially stretched polyamide film can remedy such drawbacks. Furthermore, the biaxially stretched polyamide film of the present invention is surprisingly very flexible, has high transparency, and is extremely preferable in practical use.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ryo Saito, Ryo Saito, 1000, Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryoh Chemical Industry Co., Ltd. (72) Seiichi Mukai, 1000, Kamoshida-cho, Midori-ku, Yokohama, Kanagawa (56) Reference JP 62-41261 (JP, A) JP 51-68660 (JP, A) JP 53-6355 (JP, A) JP 52-127977 (JP, A)

Claims (2)

[Claims] 1. A copolymer containing 75 to 99% by weight of an aliphatic polyamide forming unit and 25 to 1% by weight of a semi-aromatic polyamide forming unit consisting of one or more aliphatic diamines and one or more aromatic dicarboxylic acids. Polymerized polyamide (A component)
And 100 units of a semi-aromatic polyamide forming unit consisting of an aliphatic diamine and isophthalic acid and / or terephthalic acid.
˜85% by weight, and 0 to 100% of the aliphatic polyamide forming unit.
A polyamide composition comprising 15% by weight of polyamide (component B). 2. A polyamide composition according to claim 1, wherein the mixing weight ratio of the A component and the B component is (A component) :( B component) = 95: 5 to 40:60. .