JPS63145004A - Para orientating type polyamide colored film and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a high strength and high modulus film colored with any color by a method wherein optically anisotropic dope of para orientating type aromatic polyamide is spread onto a supporting surface in the form of a film and, after that, turned to be isotropic and solidified and finally the resultant not dried film is brought into contact with liquid containing dye or pigment and, after that, dried. CONSTITUTION:A film is one, which is made of para orientating type aromatic polyamide having a logarithmic viscosity number etainh of 2.5 and more, the density of which is 1.37g/cm<2> and more, the young's modulus of which is 500kg/mm<2> and more and which is colored with any color excluding yellow. Optically anisotropic dope consisting of para orientating type aromatic polyamide with the logarithmic viscosity number etainh of 2.5 and more containing at least one kind of 96wt% solvent, which is selected from among concentrated sulphric acid, chlorosulphric acid and fluorosulphric acid, is spread onto a supporting surface without changing its optical anisotropy into the form of a film. After the resultant dope is left to stand until the dope is turned to be isotropic by heating, the film is solidified and solvent in removed from the film so as to obtain a film containing 50wt% and more of moisture. The resultant film is brought into contact with liquid containing dye or pigment and dried at a temperature of 50 deg.C and higher under the condition that its shrinkage is restricted in order to obtain a colored film.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a colored film made of para-oriented aromatic polyamide and a method for producing the same. direction (hereinafter referred to as MD
The present invention relates to a para-oriented polyamide colored film that exhibits excellent mechanical properties in both the direction (hereinafter abbreviated as TD force direction) and the width direction (hereinafter abbreviated as TD force direction) and has excellent heat resistance, and a method for producing the same.

(Prior art) Polyparaphenylene terephthalamide (hereinafter referred to as PPTA)
Para-coordination type aromatic polyamides, typified by It is a polymer material that is attracting particular attention. It has also been reported that fibers spun from concentrated solutions exhibiting optical anisotropy exhibit high strength and modulus, and have already been put into industrial use. Furthermore, several examples of molding PPTA into films have been proposed (for example, Japanese Patent Publication No. 56-4521, Japanese Patent Publication No. 57-17886, etc.).

By the way, although some para-oriented aromatic polyamides are exceptionally white, most of them are colored yellow. This is presumed to be due to extremely small amounts of impurities that are inevitably present in the polymer. Furthermore, para-oriented aromatic polyamide molded articles are extremely difficult to dye or color due to their high crystallinity and dense structure.

Until now, attempts to dye para-oriented aromatic polyamide fibers have been made in JP-A-60-173187 and JP-A-60-2.
15884, No. 61-47883, and No. 52-37882, but if the amount of dyeing is insufficient, the fibers become porous during or after formation, or damage occurs. After dyeing, the mechanical properties of the fibers deteriorate significantly.

On the other hand, the technology for dyeing para-oriented aromatic polyamide films in any color has not yet been disclosed.
It has been thought that it is impossible to dye a para-oriented aromatic polyamide film, which has excellent mechanical performance due to its denseness and high orientation, without deteriorating the mechanical performance.

(Problems to be Solved by the Invention) An object of the present invention is to provide a para-oriented aromatic polyamide film that has high strength and high modulus and is colored in any color, and a method for producing the same. .

(Means for Solving the Problems) As a result of intensive research into methods for obtaining such films, the present inventors have discovered that optically anisotropic dopes of para-oriented aromatic polyamides are coated on supporting surfaces in the form of films. After that,
A special method of contacting an undried film with a moisture content of 50% by weight or more, obtained by isotroping, coagulation, and removal of the solvent with a liquid containing a dye or pigment, and then drying it, produces excellent results. It was discovered that it was possible to obtain a colored film that exhibited mechanical properties, and after further research, the present invention was completed.

That is, the first aspect of the present invention is a material made of substantially para-oriented aromatic polyamide having a logarithmic viscosity ηi n h 2.5 or more, a density of 1.37 g/cr1 or more, and a Young's modulus of 50.
The second aspect of the present invention is a film colored in a color other than yellow that is 0 kg/mm2 or more, and the logarithmic viscosity ηinh is 2.5.
An optically anisotropic dope comprising the above para-oriented aromatic polyamide and at least one solvent selected from the group consisting of concentrated sulfuric acid, chlorosulfuric acid, and fluorosulfuric acid with a concentration of 96% or more. The dope is formed into a film on a supporting surface while maintaining its anisotropy, and left until the dope is substantially converted into an optically isotropic dope by moisture absorption and/or heating, and then solidified and the solvent is substantially removed. I got 5
A method for producing a colored film, which comprises contacting a film containing water of 0% by weight or more with a liquid containing a dye or pigment, and then drying at a temperature of 50'C or more while limiting shrinkage. .

The para-oriented aromatic polyamide used in the present invention is substantially composed of units selected from the group consisting of the following structural units.

-NHA r INH- (1) -CO-A r 2- CO--= (II)-NH
-Ar3-Co-kawa(II[) where A r 1 ,
A r 2 and A r 3 are each divalent aromatic groups, and (1) and (II) are substantially equimolar when present in the polymer.

In the polyamide film of the present invention, in order to ensure good mechanical performance, Arl, Ar2 and Ar3 are each so-called para-conforming groups.

Here, the term "paraisomorphic" means that the bonds that grow the molecular chain are located coaxially or parallel to each other in opposite directions of the aromatic nucleus. Specific examples of such divalent aromatic groups include paraphenylene, 4,4'-biphenylene, 1,4-naphthylene, 1,5-naphthylene, 2,6-
Examples include naphthylene and 2,5-pyrylidine. They may be substituted one or more with non-reactive groups such as halogen, lower alkyl, nitro, methoxy, sulfonic acid, cyan groups, etc. All of Ar1, Ar2 and Ar3 may be two or more types, and may be the same or different.

The polymer used in the present invention can be produced from diamines, dicarboxylic acids, and aminocarboxylic acids corresponding to each unit by a method known so far. Specifically, there is a method in which a carboxylic acid group is first induced into an acid halide, an acid imidazolide, an ester, etc. and then reacted with an amino group, or a method in which an amino group is induced into an isocyanate group and then reacted with a carboxylic acid group. As for the polymerization method, so-called low-temperature solution polymerization method, interfacial polymerization method, melt polymerization method, solid phase polymerization method, etc. can be used.

The aromatic polyamide used in the present invention may be copolymerized with groups other than those mentioned above in an amount of about 10 mol % or less, or may be blended with other polymers.

The most typical aromatic polyamide of the present invention is
Poly-p-phenylene terephthalamide (hereinafter referred to as PPT)
A) and poly-p-benzamide.

If the degree of polymerization of the aromatic polyamide of the present invention is too low, it will not be possible to obtain a film with good mechanical properties as the object of the present invention, so the logarithmic viscosity ηinh ( 0 polymer in 100ml of sulfuric acid
．． A degree of polymerization is selected that gives a value measured at 30° C. after dissolving 5 g of the polymer.

The film of the present invention has a density of at least 1.37 g/cn1, more preferably 1.39 g/c+d. This is a density necessary to ensure the mechanical properties of the film mentioned above, and also a density that can maintain color fastness.

The film of the present invention has an initial modulus (Young's modulus) of at least 500 kg/mm2 or more, more preferably 70 kg/mm2 or more.
0 kg/mm2 or more. This is a necessary condition in order for the film of the present invention to be difficult to deform due to external forces, or to be strong even if it is thin.

The present invention is a film colored in any color other than yellow. As mentioned above, most of the para-coordination type aromatic polyamides are colored yellow as a natural color, so yellow is excluded. Dyes used for coloring include cationic dyes, anionic dyes, disperse dyes,
Examples include direct dyes, and cationic dyes are particularly preferably used. This is considered to be related to the fact that the polymer is partially sulfonated in the method of the present invention, as will be described later. As pigments, synthetic organic pigments, synthetic and inorganic pigments are used.

Next, a method for obtaining such a colored para-alignment type aromatic polyamide film will be described.

Suitable solvents for preparing the optically anisotropic dope used in forming the film of the present invention include sulfuric acid, chlorosulfuric acid, fluorosulfuric acid, or mixtures thereof at a concentration of 96% by weight or more. The sulfuric acid may be 100% or more, that is, fuming sulfuric acid, or trihalogenated acetic acid or the like may be mixed and used as long as the effects of the present invention are not impaired.

The polymer concentration in the dope used in the present invention is at room temperature (
A concentration that exhibits optical anisotropy at a temperature of about 20° C. to 30° C. or higher is preferably used, and specifically, about 9% by weight or more, preferably about 10% by weight or more. At polymer concentrations below this range, ie, polymer concentrations that do not exhibit optical anisotropy at room temperature or higher temperatures, the formed film often does not have desirable mechanical properties. Although the upper limit of the polymer concentration of the dope is not particularly limited, it is usually 20% by weight or less, and preferably 16% by weight or less for PPTA with particularly high ηinh.

The dope used in the present invention may contain additives such as fillers, light removers, ultraviolet stabilizers, heat stabilizers, antioxidants, solubilizing agents, etc., as long as they do not significantly impair the solubility of the polymer in the dope. may be mixed.

Whether the dope is optically anisotropic or optically isotropic can be determined by a known method, such as the method described in Japanese Patent Publication No. 50-8474, but the critical point depends on the type of solvent, temperature, polymer It depends on the concentration, degree of polymerization of the polymer, content of non-solvent, etc., so by investigating these relationships in advance, you can create an optically anisotropic dope and change the conditions to make it an optically isotropic dope. It is possible to change from tropic to optically isotropic.

To obtain the film of the present invention, for example, the dope is formed into a film on a support surface, and then the dope is converted from optically anisotropic to optically isotropic prior to solidification.

In order to convert optical anisotropy to optical isotropy, specifically, before solidifying an optically anisotropic dope formed into a film on a support surface, the concentration of the solvent forming the dope is lowered by absorbing moisture. The dope can be transformed into an optically isotropic region by changing the solubility of the solvent and the polymer concentration, or the dope can be heated to transform it into an optically isotropic region simultaneously or sequentially, or the dope can be transformed into an optically isotropic region by heating and moisture absorption. This can be achieved by using them together.

The dope can be made to absorb moisture, for example, by leaving it in the air for a certain period of time or more.

The air in this case preferably has a relative humidity of 50% or more.

Further, actively applying humidification to a normal humid atmosphere is a desirable embodiment because it shortens the time until optical isotropy is achieved, and when heating is used in combination, the heating temperature can be lowered. If the relative humidity exceeds 99%, water will condense on the dope at low temperatures, leading to polymer precipitation.
Relative humidity of 100% or more can also be used at temperatures of 45° C. or higher, although the flatness of the film may be lost.

In addition, in a method that uses heating simultaneously with moisture absorption or after moisture absorption, for example, when sulfuric acid is used as a solvent, the temperature at which optical anisotropy substantially disappears and the dope converts to optical isotropy is: Polymer concentration, degree of polymerization, sulfuric acid concentration,
Although it varies depending on the thickness of the dope and the degree of moisture absorption,
Generally, the temperature is preferably about 45°C or higher, and when considering the decomposability of the polymer, it is generally desirable that the upper limit is not too high.
It is desirable to select a value that does not exceed C.

Although the mechanism of optical isotropy caused by this moisture absorption is not necessarily clear, it is probably because the liquid crystal region of the PPTA-solvent system is considerably reduced due to the decrease in polymer concentration and solvent concentration due to moisture absorption. This moisture absorption alone is sufficient to achieve optical isotropy, but if this is further accompanied by heating, isotropy can be achieved in a short period of time. This method is particularly effective when the dope is thick.

In the present invention, the dope coagulating liquid that can be used is, for example, dilute sulfuric acid containing about 70% by weight or less of water, aqueous sodium hydroxide solution containing about 20% by weight or less, aqueous ammonia, about 5% by weight or less
These include 0% by weight or less sodium chloride aqueous solution and calcium chloride aqueous solution. The temperature of the coagulation bath is not particularly limited, and is usually in the range of about -5°C to 50°C.

Since the coagulated film as it is contains acid, it is necessary to wash and remove the acid as much as possible in order to produce a film whose mechanical properties are less likely to deteriorate due to heating. Specifically, it is desirable to remove the acid content to about 500 ppm or less. Water is usually used as the cleaning liquid, but if necessary, hot water may be used, or washing may be performed by neutralizing with an alkaline aqueous solution and then washing with water. Cleaning is carried out, for example, by running the film in a cleaning liquid or by spraying the cleaning liquid.

In the present invention, the film produced in this manner retains at least 50% by weight of water, preferably 80% by weight or more of water without drying, and the film contains a dye or pigment. must be brought into contact with. When the water content is less than 50% by weight, the dye is in a so-called half-dry state, and the diffusion of the dye or pigment from the liquid containing the dye or pigment is significantly reduced, making it impossible to dye to a practical extent.

The contact with the dye or pigment is preferably carried out by impregnating the film with an impregnating agent containing the dye or pigment described above. Particles of dyes and pigments are molecularly dispersed in a solution state in an impregnating agent, and their particle size is usually 0.1 μm or less. Even if the impregnating agent is not water-soluble, the impregnating treatment can be carried out in the form of an emulsion, dispersion, or colloid, but from the viewpoint of ease of impregnation, a particle size of 0.01 μm or less is most preferably used. At this time, these emulsions,
Additives such as surfactants may be added to stabilize the dispersion or promote coloring.

Impregnation can be carried out by immersing the film in a liquid containing an impregnating agent, or by spraying, showering, or the like.

The impregnation temperature can be set arbitrarily between room temperature and boiling point.
Higher temperatures are preferred. Impregnating agent concentration is also 0.1% by weight ~ 99%
Any between % by weight.

Since impregnation with dyes and pigments is generally diffusion-controlled, the impregnation temperature, time, and impregnation concentration should be determined depending on the desired degree of coloring. The content of the dye or pigment that has a coloring effect is generally about 0.1 to 20% by weight, preferably 1 to 10% by weight.

The film colored in this way is dried after cleaning the dye or pigment adhering to the surface, but it can also be stretched prior to drying if desired. That is, the wet film before drying is 1.01 to 1 in one or two directions.
．． By stretching the film by about 4 times, the mechanical properties of the film can be improved.

It is necessary to dry the film under tension, under constant length, or while slightly stretching the film while allowing the film to shrink. If a film that tends to shrink with the removal of a cleaning solution (e.g., water) is dried without any restriction on shrinkage, microscopically non-uniform structure formation (crystallization, etc.) may occur. The resulting film may lose its flatness or curl. To dry while limiting shrinkage, for example, a tenter dryer or drying between metal frames can be used.

Other conditions related to drying are not particularly limited.
Any method can be selected from methods using heated gas (air, nitrogen, argon, etc.) or room temperature gas, methods using radiant heat such as electric heaters or infrared lamps, and dielectric heating methods.

It is important that the drying temperature of the film is 50°C or higher. This is because drying at a temperature below 50° C. results in insufficient densification of the film structure (low density) and insufficient color fastness. Drying temperature is preferably 100-3
It is 00℃.

Furthermore, in the present invention, when dissolving in a sulfuric acid-based solvent and molding, some of the aromatic nuclei in the polymer chain may be sulfonated depending on the conditions, but this may reduce the mechanical properties of the resulting film. Since the effect of improving the exhaustion power of the impregnating agent (cationic dye, etc.) can be seen in the range where it is not accompanied by sulfonation, it is one of the preferred embodiments to actively advance sulfonation. Such sulfonation can be achieved by using heating to make the optically anisotropic dope isotropic, heat generated during moisture absorption, and the like.

(Example) Examples and reference examples (manufacturing examples of PPTA) of the present invention are shown below, but these reference examples and examples are for explaining the present invention, and are not intended to limit the present invention. .

In the examples, parts by weight or weight % are shown unless otherwise specified.

Logarithmic viscosity ηinh is 98% sulfuric acid 100ml with 0 polymer
, 2g was dissolved and measured at 30°C in a conventional manner.

The viscosity of the dope was measured using a type B viscosity needle at a rotation speed of 1 rpm. The thickness of the film was measured with a dial gauge with a measuring surface of diameter 'l + u. The strength elongation and modulus are determined by cutting a film sample into a 100 IIXIO dragon rectangle using a constant speed extension type strength elongation measuring machine, and applying a load of - with an initial grip length of 3011 and a tensile speed of 30 n+/min.
The elongation curve was drawn five times and calculated from this. Density was measured at 30°C by density gradient tube method using carbon tetrachloride-toluene.

Example 1 A PPTA polymer having an ηinh of 5.5 was dissolved in 99.7% sulfuric acid at a polymer concentration of 12.0% to obtain a dope with optical anisotropy at 60°C. The viscosity of this dope was measured at room temperature and was found to be 14,500 voids. To facilitate film formation, the dope was kept at about 70° C. and degassed under vacuum. In this case as well, it has optical anisotropy as above,
The viscosity was 4200 boids. This dope is passed from the tank through a filter, passed through a gear pump while keeping it at about 70°C, and passed through a 1.5m bent pipe to the die.
The cast dope was cast from a die with a slit of 300 mm to a mirror-polished Hastelloy belt, and the cast dope was blown with air at about 90°C, which is about 95% of the relative temperature, to perform an optical isodynamic ratio. After holding it on the belt for 1 minute, it was introduced together with Held into a 20% by weight sulfuric acid aqueous solution at 0° C. to solidify. The coagulated film was then peeled off from the belt and washed by running it through a water tank at about 20° C. via rotating rollers (residence time: about 3 minutes) to obtain a gel-like coagulated film with a moisture content of about 400% by weight.

This film was brought into contact with an aqueous solution containing 5% by weight of the cationic dye Diacrylic Red GL-N (manufactured by Mitsubishi Kasei Corporation) at 80°C for 5 minutes to impregnate it with the dye, and then the obtained colored film was washed with water. The film was sandwiched between two stainless steel frames of about IQcm x 15cm and dried for a fixed length in an air oven kept at 200°C to obtain a red film. This film was immersed in boiling water for about 30 minutes, but the color did not fade at all.

Comparative Example 1 The gel-like coagulated film obtained in Example 1 was once heated to 120°C.
After drying to a water content of about 30% by weight, dyeing was carried out under the conditions shown in Example 1, but the color was only slightly red.

Comparative Example 2 The gel-like coagulated film obtained in Example 1 was dyed under the conditions shown in Example 1, then washed with water, and the colored film obtained was placed in two stainless steel frames of about 10 cm x 15 cm. It was sandwiched and air-dried at room temperature to obtain a red film. When this film was placed in boiling water for about 30 minutes, there was a great deal of decolorization.

Example 2 The gel-like coagulated film obtained in Example 1 was mixed with 5% by weight of disperse dye Dianic Sprue BG-FS (manufactured by Mitsubishi Kasei Corporation) and 1 g/j of Disper TL as a dispersant! was impregnated with the dye by contacting with a solution at 80°C for 5 minutes, and then washed with water and dried in the same manner as in Example 1.
A blue film was obtained. When this film was placed in boiling water for 30 minutes, no decolorization was observed.

Comparative Example 3 The film obtained in Example 1 was heated to a moisture content of 2 at 120°C.
After drying to below % by weight, dyeing was carried out under the conditions shown in Example 2, but no coloring was observed.

Example 3 The film obtained in Example 1 was brought into contact with an aqueous solution containing 5% by weight of the acid dye Diazid Alizarin Light Blue 4GL (manufactured by Mitsubishi Kasei Corporation) for 5 minutes to soak in the dye, and then further washed with water. , dried under the conditions shown in Example 1,
A blue film was obtained.

Example 4 The film obtained in Example 1 was coated with organic pigment Ray Red 4.
After being brought into contact with a solution containing 5% by weight of R (manufactured by Tokyo Ink Co., Ltd.) for 5 minutes, it was dried under the conditions shown in Example 1 to obtain a blue film.

The processing conditions and physical properties of these films are summarized in Table 1.

Table 1 (Effects of the Invention) The film of the present invention is a novel film that has good mechanical properties represented by high strength and high modulus, and is colored in any color. Further, the film of the present invention has
It has high heat resistance and high dielectric constant. Taking advantage of these performance characteristics, the film of the present invention is useful as an insulator for capacitors, a base film for magnetic tapes, a tape for thermal transfer printers, etc. In particular, since it is colored, it can be used as heat-resistant identification tapes and sheets, It can be suitably used for identification wire coatings, and is also useful for packaging materials, plate-making materials, photographic films, and the like.

Claims (2)

[Claims] (1) Made of substantially para-oriented aromatic polyamide with a logarithmic viscosity ηinh of 2.5 or more, with a density of 1.37 g/cm
A para-oriented polyamide colored film colored other than yellow, with a Young's modulus of ^3 or more and a Young's modulus of 500 kg/mm^2 or more. (2) A para-oriented aromatic polyamide having a logarithmic viscosity ηinh of 2.5 or more and at least one solvent selected from the group consisting of concentrated sulfuric acid, chlorosulfuric acid, and fluorosulfuric acid with a concentration of 96% by weight or more. After forming an optically anisotropic dope into a film on a support surface while maintaining its optical anisotropy, and leaving it until the dope is substantially converted into an optically isotropic dope by moisture absorption and/or heating, A film containing 50% by weight or more water obtained by coagulating and substantially removing the solvent is brought into contact with a dye or pigment-containing liquid, and then dried at a temperature of 50° C. or higher while limiting shrinkage. A method for producing a para-oriented polyamide colored film, characterized by: