JP3185503B2 - Aromatic polyamide film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aromatic polyamide film having excellent heat resistance and mechanical properties.

[0002]

2. Description of the Related Art An aromatic polyamide film obtained from a diisocyanate and a dicarboxylic acid or a diamine and a diacid chloride, particularly a para-oriented aromatic polyamide film, has excellent heat resistance and mechanical properties. It is used for recording materials such as films, electric and electronic applications, and information-related fields.

[0003]

However, in recent years, in the field of flexible printed circuit boards and magnetic materials, particularly base films for thin magnetic tapes, the mechanical properties, especially Young's modulus, have been further improved and the longitudinal direction of the film has been improved. There is an increasing demand for a film having an excellent Young's modulus not only in (MD) but also in the width direction (TD).

[0004] In response to this demand, a method of improving mechanical properties by stretching, which is generally performed in film production, has been attempted for a para-oriented aromatic polyamide film. Even if a high Young's modulus is obtained in the stretching direction, the mechanical properties in the non-stretching direction are greatly reduced, so that the obtained film is not suitable for practical use. In order to compensate for this, if it is attempted to stretch in a direction perpendicular to the previously stretched direction, it is often difficult to stretch because of the rigidity of the molecular structure inherent to the polymer.
When it is difficult to give sufficient mechanical properties to D, and when the mechanical properties of MD are greatly reduced even if it can be stretched, or when the film becomes brittle even if high Young's modulus can be obtained for both MD and TD. There is a possibility that it is not suitable for practical use as a magnetic material such as a base film of a magnetic tape or an industrial material such as an FPC film.

The present invention solves the above-mentioned drawbacks found in the prior art and can meet the demands of the industry, has excellent heat resistance and mechanical properties, and has extremely low mechanical properties in a non-stretching direction in a stretched film. It is intended to provide a small aromatic polyamide film.

[0006]

According to the present invention, in order to attain the object, at least 60 mol% of the repeating units are contained.

Embedded image An aromatic polyamide film comprising:

(Where R ₁ , R ₂ , R ₃ are

Embedded image Two or more of these may be included, and a part of the hydrogen on the aromatic ring may be a halogen, a C _{1 to} C ₃ alkyl group, a C _{1 to} C ₃ alkoxy group, a nitro group or It may be substituted with a cyano group. The molar ratio between p and q is in the range of 80:20 to 99.9: 0.1. )
The aromatic polyamide film in the present invention includes

Embedded image And at least 60 mol% of a repeating unit represented by the formula: and R ₁ , R ₂ and R ₃ are

Embedded image Must be selected from those having the structure represented by The reason is that the substantial repeating unit has high regularity, a rigid structure, and high mechanical properties and heat resistance due to containing an aromatic ring, and furthermore, a specific amount of a fluorene group is contained. This is because the object of the present invention, in which the mechanical properties of the stretched film in the non-stretching direction is extremely small, is achieved. When the repeating unit in the present invention is less than 60 mol%, the heat resistance and mechanical properties, particularly the Young's modulus, decrease, and further, the mechanical properties in the non-stretching direction of the stretched film are significantly reduced, thereby achieving the object of the present invention. If R ₁ , R ₂ , and R ₃ do not have the above structure, mechanical properties and heat resistance will be significantly reduced.

In the present invention, the ratio of p and q constituting the above repeating unit is p: q = 80: 20 to 99.9:
It is in the range of 0.1. This is because, in the aromatic polyamide film of the present invention, when the ratio q of the repeating unit containing a fluorene group is in the above range, the effect of the present invention that the mechanical property decrease in the non-stretching direction in the stretched film is extremely small. Is obtained. q is 0.
If it is less than 1, the characteristic that the decrease in mechanical properties in the non-stretching direction is small is lost, and if q is more than 20, the mechanical properties are decreased in both the stretching direction and the non-stretching direction due to the bulkiness of the fluorene group. The effect of the present invention that the decrease in mechanical properties in the non-stretching direction is extremely small cannot be satisfied. The ratio of p: q is p: q = 80: 20 to 99.9:
There is no particular limitation as long as it is within the range of 0.1, but the point of minimizing the decrease in mechanical properties in the non-stretching direction, the point of maintaining high mechanical properties in the stretching direction, and economy (cost)
The range of p: q = 85: 15-99.7: 0.3 is preferable from the point of view, More preferably, p: q = 90: 10-9.
The range is 9.5: 0.5.

The monomer used to obtain the aromatic polyamide film of the present invention varies depending on the polymerization method. Here, diamine and diacid chloride used in low-temperature solution polymerization will be described as an example.

In order to obtain the aromatic polyamide film of the present invention, it is necessary to carry out copolymerization using a diamine component containing a fluorene group in order to introduce a fluorene group.
Representative examples of such a diamine include 9,9-bis (4-aminophenyl) fluorene (hereinafter BAFL), in which a part of hydrogen on the aromatic ring of BAFL is substituted by a substituent. For example, 9,9-bis (3-methyl, 4-aminophenyl) fluorene,
9-bis (3-ethyl, 4-aminophenyl) fluorene or the like may be used.

The diamine component constituting the repeating unit represented by the ratio p includes paraphenylenediamine,
2-chloroparaphenylenediamine, 2,3-dichloroparaphenylenediamine, 2,5-dichloroparaphenylenediamine, 2,6-dichloroparaphenylenediamine, 2,3,5-trichloroparaphenylenediamine,
2-bromoparaphenylenediamine, 2,6-dibromoparaphenylenediamine, 2-fluoroparaphenylenediamine, 2,6-difluoroparaphenylenediamine, 2
-Nitroparaphenylenediamine, 2,6-dinitroparaphenylenediamine, 2-cyanoparaphenylenediamine, 2,6-dicyanoparaphenylenediamine, 2-
Methyl paraphenylenediamine, 2,6-dimethylparaphenylenediamine, 2-ethylparaphenylenediamine, 4,4′-biphenylenediamine, 3,3′-biphenylenediamine, 3,4′-biphenylenediamine,
1,4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, 1,4-bis (4
-Aminophenyl) benzene is a representative example.

As the diacid chloride component, terephthalic acid chloride, 2-chloroterephthalic acid chloride,
2,3-dichloroterephthalic acid chloride, 2,5-dichloroterephthalic acid chloride, 2,6-dichloroterephthalic acid chloride, 2,3,5-trichloroterephthalic acid chloride, 2-bromoterephthalic acid chloride,
2,6-dibromoterephthalic acid chloride, 2-fluoroterephthalic acid chloride, 2,6-difluoroterephthalic acid chloride, 2-nitroterephthalic acid chloride,
2,6-dinitroterephthalic acid chloride, 2-cyanoterephthalic acid chloride, 2,6-dicyanoterephthalic acid chloride, 2-methylterephthalic acid chloride,
2,6-dimethyl terephthalic acid chloride, 2-ethyl terephthalic acid chloride, 4,4′-biphenyldicarbonyl chloride, 3,3′-biphenyldicarbonyl chloride, 3,4′-biphenyldicarbonyl chloride, 1,4- Naphthalenedicarbonyl chloride,
1,5-naphthalenedicarbonyl chloride, 2,6-
Naphthalenedicarbonyl chloride, 1,4-bis (p
-(Phenylenecarbonyl chloride) benzene is a typical example.

As described above, the aromatic polyamide constituting the present invention refers to an aromatic polyamide containing 60% or more of the above-mentioned repeating unit, and 40% of the repeating unit improves the solubility of the polymer and the obtained film. The copolymer may be copolymerized with other components for the purpose of imparting an appropriate degree of flexibility.

Examples of such copolymerized units include diamines such as metaphenylenediamine, 4-chlorometaphenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone,
4,4'-diaminodiphenyl sulfide, 4,4'-
Diaminodiphenylmethane, 4,4′-diaminodiphenylketone, 3,3′-diaminodiphenylether,
3,3′-diaminodiphenylsulfone, 3,3′-
Diaminodiphenyl sulfide, 3,4′-diaminodiphenyl ether and the like, and metaphenylenediamine, 4,4′-diaminodiphenyl ether,
Those having a bent structure such as 4'-diaminodiphenylmethane are preferred. Examples of diacid chloride include isophthalic chloride, 4-chloroisophthalic chloride, 4,6-dichloroisophthalic chloride, and 4-dichloroisophthalic chloride.
Bromoisophthalic acid chloride, 4-fluoroisophthalic acid chloride, 4-nitroisophthalic acid chloride, 4
Representative examples include -methylisophthalic acid chloride and 4-cyanoisophthalic acid chloride.

The thickness of the aromatic polyamide film obtained according to the present invention is preferably 1 to 200 μm, more preferably 1 to 50 μm.

The aromatic polyamide film of the present invention has a Young's modulus of 800 kg / mm in an unstretched film.
² or more, more preferably 900 kg / mm ²
That is all. In the uniaxially stretched film, the Young's modulus in the stretching direction and the non-stretching direction are each 1500 kg / m.
m ² , desirably 800 kg / mm ² or more. Next, a method for obtaining an aromatic polyamide film according to the present invention will be described.

The aromatic polyamide of the present invention may be prepared by a diisocyanate method in which a diisocyanate or dicarboxylic acid is reacted in a polar solvent at a high temperature, a diamine method in which a diamine or diacid chloride is reacted in a polar solvent at a low temperature, a diamine or diacid chloride. There is an interfacial polymerization method in which each is dissolved in a poor solvent for the other and brought into contact with each other to obtain a polymer.The polymerization may be performed by any method, but it is stable because the reaction proceeds under mild conditions. It is desirable to use a diamine method in which a polymer having a predetermined degree of polymerization is obtained. Here, the diamine method will be described as an example.

As a polymerization method, at a temperature of 0 to 70 ° C.,
(1) dissolving or slurrying a diamine with a polar solvent,
A method in which an acid chloride is added in the form of a solution, a melt, or a powder under stirring, and stirring is further continued for 1 to 15 hours to complete the reaction. (2) There is a method in which a mixture of powders of an acid chloride and a diamine is added to a polar solvent to cause a reaction, and any method may be used. The polar solvent referred to here is an aprotic organic solvent such as N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, hexamethylphosphoramide, dimethylsulfoxide and the like. Thereafter, it is desirable to neutralize hydrochloric acid generated from the amine and the acid chloride with an inorganic alkali such as calcium carbonate and lithium carbonate from the viewpoint of the stability of the solution.

The intrinsic viscosity of the aromatic polyamide polymer obtained as described above is preferably in the range of 0.5 to 7.0. If it is less than 0.5, the resulting film may be very brittle and poor in practicality. If it is too high, the solution viscosity may increase extremely.

The aromatic polyamide polymer thus obtained may be used as it is for film formation, or may be washed with a large amount of water to remove hydrochloric acid, hydrochloride, etc., dried, and then a dope dissolved in a solvent may be prepared. It can be used for the membrane.

The dope used in the film formation preferably has a polymer concentration of 5 to 40% by weight in view of the stability of the film formation. In order to improve the solubility of the polymer, lithium dope, lithium bromide or the like is used. May be included.

Next, the method for producing the aromatic polyamide film of the present invention will be described.

When an inorganic salt as a solubilizing agent or a neutralizing agent is contained in the film forming stock solution, a dry-wet method or a wet method is preferred. When a film is formed by a dry-wet method, a stock solution is extruded from a die onto a support such as a drum or an endless belt to form a thin film, which is then introduced into a dry process. Then, the solvent is scattered and concentrated from the thin film layer, and the thin film is dried until it has a self-supporting property. At this time, it is necessary to adjust so that the solvent does not suddenly scatter from the film surface.
It is dried at 0 ° C to 200 ° C, preferably 70 ° C to 150 ° C for several tens seconds to several tens minutes. If the temperature is lower than 50 ° C., the drying time becomes longer. If the temperature is higher than 200 ° C., voids are generated due to rapid heating.
This is because surface roughening or the like occurs and a practical film cannot be obtained as an industrial material or a magnetic material. After the dry process, the film is peeled from the support and introduced into the wet process. Here, the ionic inorganic compound contained in the film is removed. This bath is generally composed of an aqueous medium, and may contain an organic solvent, an inorganic salt or the like in addition to water. However, generally, the water content is 30% or more, preferably 50% or more, and the bath temperature is usually 0 to 100 ° C.

In this wet process, the peeled film is immersed in such a bath under tension, and the inorganic compounds in the film are extracted to less than 0.1, preferably to 0.05% or less. The amount of the inorganic salt as a dissolution aid is at most the neutralized salt formed by neutralization, or the same amount as the neutralized salt, and the amount of the inorganic salt is small, so that the extraction speed is high, and the inorganic salt or the organic salt in the bath is used. Recovery of the solvent is also easy.

Further, the film after the dry process is stretched within a range of 1.05 to 2.5 times in the longitudinal direction (MD) of the film before being introduced into the wet process, in a wet bath, or after the wet process. Done. If it is 1.05 times or less, no improvement in mechanical properties in the stretching direction is observed, and if it is 2.5 times or more, fibrillation occurs in the stretching direction and only an extremely brittle film is obtained. The film thus obtained is then
0 ° C. to 500 ° C., preferably 10 to 250 ° C. to 350 ° C.
The film is heat-treated under tension for seconds to 60 minutes to form a final film. Before or during heat treatment, the film is stretched in the film width direction (TD) by 1.05 to 2.5 times and biaxially stretched. Films can also be obtained.

When the film is formed by a wet method, a method is employed in which the undiluted solution is directly extruded from a die into a film-forming bath, or is once extruded onto a support such as a drum and introduced together with the support into the above-mentioned wet bath. You. In the wet bath, the ionic inorganic compound and the organic solvent contained in the film are extracted. The wet bath has the same composition as the dry-wet film-forming bath, and the addition of an organic solvent, an inorganic salt or the like in order to adjust the desalting and desolvation rates is the same as described above. Further, in the wet bath or after the completion of the wet process, the film can be stretched in the range of 1.05 to 2.5 times the MD in the same manner as in the dry-wet method. Further, similarly to the dry-wet method, the film after the wet process is subjected to a temperature of 200 ° C to 500 ° C, preferably 250 ° C to 35 ° C.
The film is heat-treated at 0 ° C. under tension for 10 seconds to 60 minutes to form a final film.
It is also possible to obtain a biaxially stretched film by stretching D in the range of 1.05 to 2.5 times.

[0027]

[Method of measuring characteristic values] The characteristic values of the present invention are determined by the following measuring methods.

(1) Young's modulus and strength Measured according to JIS 1702 and ASTM D882-67.

(2) Intrinsic Viscosity Intrinsic Viscosity = ln (t / t _O ) / C (dl / g) Here, C: number of grams of polymer in 1 dl of solution t _O : flow-down time (second) of solvent alone t : Flowing time of solution (second) 30 ° C. using N-methyl-2-pyrrolidone as a solvent
Was measured.

[0030]

【Example】

Example 1 32.78 g of 2-chloroparaphenylenediamine (0.
23 mol), 3.50 g (0.0175 mol) of 4,4'-diaminodiphenyl ether and 9,9-bis (4-
0.871 g of aminophenyl) fluorene (BAFL)
(0.0025 mol) with N-methyl-2-pyrrolidone 6
00 ml is charged into a 1000 ml four-necked flask, uniformly stirred and dispersed in a nitrogen stream, and cooled to 10 ° C. by an ice bath. 50.78 g of terephthalic acid chloride was added to this system.
(0.25 mol) was gradually added so that the temperature in the flask system did not exceed 30 ° C., and stirring was continued for 1 hour after completion of the addition, whereby the polymerization system became an extremely viscous solution. 25.0 g (0.25 mol) of calcium carbonate was added to this solution,
After stirring for an hour, dehydrochlorination was performed. The polymer solution was 3300 poise when measured with a rotary viscometer, and the intrinsic viscosity was 3.2. This dope is 5 mm thick, 300
about 1 mm on a glass plate of
Cast to a thickness of 00 μm and place in a hot air oven at 120 ° C for 10
After drying for one minute, it was peeled off from the glass plate, fixed on a uniaxial stretching machine, and stretched in the air. Subsequently, after immersion in running water at 40 ° C. for 15 minutes, heat fixing was performed in a hot air oven at 330 ° C. for 1 minute under tension. The stretched film was stretched in the direction perpendicular to the previous stretching and then heat-fixed. The physical properties of the obtained film are shown in Tables 1 and 2.

Example 2 The thickness of the dope prepared in Example 1 was 5 mm, 300 mm × 3
Approximately 100 μm on a 00 mm glass plate with an applicator
The film was cast to a thickness, immersed in running water at 40 ° C. for 15 minutes, and peeled from the support, and stretched in water. Then 33
Heat set under tension in a hot air oven at 0 ° C. for 1 minute. The stretched film was stretched in the direction perpendicular to the previous stretching and then heat-fixed. Tables 1 and 2 show the physical properties of the obtained film.

Example 3 23.52 g (0.218 mol) of paraphenylenediamine, 4,01'-diaminodiphenyl ether 5.01
g (0.025 mol) and 2.613 g of BAFL (0.025 mol).
075 mol) in 600 ml of N-methyl-2-pyrrolidone
Was charged into a 1000 ml four-necked flask, uniformly stirred and dispersed in a nitrogen stream, and cooled to 10 ° C. with an ice bath. 59.37 g of 2-chloroterephthalic acid chloride was added to this system.
(0.25 mol) was gradually added so that the temperature in the flask system did not exceed 30 ° C., and stirring was continued for 1 hour after completion of the addition, whereby the polymerization system became an extremely viscous solution. 25.0 g (0.25 mol) of calcium carbonate was added to this solution,
After stirring for an hour, dehydrochlorination was performed. The polymer solution was 3400 poise when measured with a rotary viscometer, and the intrinsic viscosity was 3.3. This dope was dried, stretched and heat-treated in the same manner as in Example 1. Tables 1 and 2 show the physical properties of the obtained film.

Comparative Example 1 33.15 g of 2-chloroparaphenylenediamine (0.
233 mol) and 3.50 g (0.0175 mol) of 4,4'-diaminodiphenyl ether were charged into a 1000 ml four-necked flask with 600 ml of N-methyl-2-pyrrolidone, and uniformly stirred and dispersed in a nitrogen stream. 10
Cool to ° C. In this system, terephthalic acid chloride 50.
78 g (0.25 mol) was gradually added so that the temperature in the flask system did not exceed 30 ° C., and stirring was continued for 1 hour after completion of the addition, whereby the polymerization system became an extremely viscous solution. 25.0 g (0.25 mol) of calcium carbonate was added to this solution,
The mixture was stirred at 3 ° C. for 3 hours to perform dehydrochlorination. When this polymer solution was measured with a rotary viscometer, it was 3200 poise,
The intrinsic viscosity was 3.2. This dope was subjected to the same drying, stretching and heat treatment as in Example 1. The results are shown in Tables 1 and 2.

Comparative Example 2 33.29 g (0.248 mol) of paraphenylenediamine and 0.871 g (0.0025 mol) of BAFL were added to N
-600 ml of -methyl-2-pyrrolidone is charged into a 1000 ml four-necked flask, uniformly stirred and dispersed in a nitrogen stream, and cooled to 10 ° C by an ice bath. 50.76 g (0.25 mol) of isophthalic acid chloride is gradually added to this system so that the temperature in the flask system does not exceed 30 ° C., and stirring is continued for 1 hour after completion of the addition, whereby the polymerization system becomes an extremely viscous solution. It became. To this solution was added 25.0 g of calcium carbonate (0.2
5 mol) and stirred at 40 ° C. for 3 hours to perform dehydrochlorination. When this polymer solution was measured with a rotary viscometer, 27
It was 00 poise and the intrinsic viscosity was 2.5. This dope was subjected to the same drying, stretching and heat treatment as in Example 1.
The results are shown in Tables 1 and 2.

Comparative Example 3 20.28 g (0.188 mol) of paraphenylenediamine and 21.78 g (0.0625 mol) of BAFL were added to N
-600 ml of -methyl-2-pyrrolidone is charged into a 1000 ml four-necked flask, uniformly stirred and dispersed in a nitrogen stream, and cooled to 10 ° C by an ice bath. To this system, 59.37 g (0.25 mol) of 2-chloroterephthalic acid chloride was gradually added so that the temperature in the flask system did not exceed 30 ° C, and stirring was continued for 1 hour after completion of the addition, whereby the polymerization system became extremely viscous. Solution. 25.0 g of calcium carbonate was added to this solution.
(0.25 mol), and the mixture was stirred at 40 ° C. for 3 hours to perform dehydrochlorination. When this polymer solution was measured with a rotary viscometer, it was 2900 poise and the intrinsic viscosity was 2.6. This dope was subjected to the same drying, stretching and heat treatment as in Example 1. The results are shown in Tables 1 and 2.

[0036]

[Table 1]

[Table 2]

[0037]

As described above, the aromatic polyamide film of the present invention comprises:
Excellent heat resistance and mechanical properties, and by introducing a specific amount of fluorene group, the decrease in mechanical properties in the non-stretching direction is extremely small in uniaxially stretched films, and high in both stretching and non-stretching directions in biaxially stretched films Since it has excellent mechanical properties, it is applied to various application fields such as base film applications for high-density magnetic recording tapes, wire coating applications, capacitors, and flexible printed circuit boards. Excellent for tape base film applications.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI C08L 77:00 (58) Investigated field (Int.Cl. ⁷ , DB name) C08G 69/00-69/36

Claims (1)

(57) [Claims] (1) at least 60 mol% of the repeating unit is An aromatic polyamide film comprising:
(Where R ₁ , R ₂ , R ₃ are Two or more of these may be included, and a part of the hydrogen on the aromatic ring may be a halogen, a C _{1 to} C ₃ alkyl group, a C _{1 to} C ₃ alkoxy group, a nitro group or It may be substituted with a cyano group. The molar ratio between p and q is in the range of 80:20 to 99.9: 0.1. )