JPH10212363A - Colored aromatic polyamide film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a colored arom. polyamide film which is prepd. from a p-oriented arom. polyamide and is excellent in mechanical properties and heat resistance and esp. in dimensional stability and electrical insulation properties. SOLUTION: This film mainly comprises a p-oriented arom. polyamide having a logarithmic viscosity of 3.5 or higher and has a Young's modulus of 500kg/mm<2> or higher in both the longitudinal and the width directions, an elongation of 8% or higher, a coefficient of expansion by moisture absorption of 40×10<-6> /%RH or lower, and a light transmission at 530nm of 40% or lower. The process for producing this film is characterized in that, in forming a p- oriented arom. polyamide film by a wet process, a dry process or a dry and wet process, a carbohydrate is incorporated into the film before heat treatment and then the film is heat treated at 300-500 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film made of para-oriented aromatic polyamide, and more particularly to a film in a longitudinal direction (hereinafter abbreviated as MD).
The present invention relates to a colored film exhibiting excellent mechanical performance in both the width direction and the width direction (TD direction), and further having excellent heat resistance, dimensional stability, and electrical insulation.

2. Description of the Related Art Para-oriented aromatic polyamides have excellent crystallinity and a high melting point, and have high mechanical strength due to a rigid molecular structure. Used industrially. With respect to the use of polyparaphenylene terephthalamide (hereinafter, referred to as PPTA), which is a typical para-oriented aromatic polyamide, as a film, for example, Japanese Patent Publication No. Sho 57-1788
No. 6 discloses an optically anisotropic dope prepared by dissolving PPTA in a strong acid such as concentrated sulfuric acid, heated to optical isotropic just before coagulation, and then coagulated to obtain a transparent and mechanically isotropic material. It has been put to practical use by a method of obtaining an excellent film. When PPTA is formed, a film solidified as it is without changing the optically anisotropic dope to optically isotropic is generally opaque, and the mechanical properties in the width direction of the film and the dimensional stability are poor. Industrial application is difficult.

A transparent and isotropic film formed from an organic solvent solution by solubilizing an organic solvent by copolymerizing a unit in which a halogen is introduced into an aromatic nucleus of a para-oriented aromatic polyamide. (For example, Japanese Patent Publication No. 56-45421). Such a para-oriented aromatic polyamide film has excellent mechanical properties,
Because it has heat resistance, chemical resistance, etc., for example, insulating substrates such as flexible printed wiring boards (FPC), carrier tapes for tape automated bonding (TAB), acoustic members such as speaker diaphragms and voice coils, and solar cells The application as a substrate or the like is expected. The para-oriented aromatic polyamide film which is excellent in mechanical properties and industrially available is usually pale yellow and transparent,
It has a light transmittance of a wavelength of m or more. However, for example, when using a film for re-covering, avoiding the influence of light transmission to the inside, or when optically processing a member formed on the film surface, avoiding transmission of light used for processing to the back surface In some cases, a film having a low light transmittance is required to meet such requirements.

As a method of coloring a para-oriented aromatic polyamide film, a film containing water and a liquid containing a dye such as a cationic dye, an anionic dye, a disperse dye, a direct dye or a pigment such as an organic pigment or an inorganic pigment are used. A method of drying after contacting has been proposed (for example,
JP-A-3-145004, JP-A-63-243145, JP-A-3-217429). This film has a problem that the dimensional stability with respect to humidity and the electrical insulation are reduced as compared with a film without coloring. This is considered to be because the dyes used for coloring contain a large number of acidic or basic functional groups and metal elements, and are used in applications where dimensional stability and electrical insulation are strongly required. There was a problem.

On the other hand, in the production of PPTA film,
By drying and heat-treating with a small amount of strong acid such as sulfuric acid used as a solvent remaining, a colored film can be obtained to some extent, but the mechanical properties are extremely low and not at a level that can be used industrially.

SUMMARY OF THE INVENTION An object of the present invention is to provide a colored film using a para-oriented aromatic polyamide and having excellent mechanical performance and heat resistance, and particularly excellent in dimensional stability and electrical insulation. To provide a colored film.

Means for Solving the Problems The present inventors have conducted intensive studies to obtain a colored film meeting the above-mentioned object, and as a result, have found that a film containing a para-oriented aromatic polyamide as a main component has a specific mechanical property. A colored film having physical properties, a coefficient of hygroscopic expansion and a light transmittance is useful for these purposes, and a colored film having the above properties can be obtained by heat-treating a specific compound contained in the film. The present invention has been completed and further research has been completed to complete the present invention.

That is, the present invention relates to a film comprising a para-oriented aromatic polyamide having a logarithmic viscosity of 3.5 or more as a main component, and having a Young's modulus of 500 kg / mm ² or more in both the longitudinal and width directions. The degree is 8% or more,
The coefficient of hygroscopic expansion is 40 × 10 ⁻⁶ /% RH or less;
When forming an aromatic polyamide colored film having a light transmittance at 0 nm of 40% or less and a para-oriented aromatic polyamide film by a wet method, a dry method, or a dry / wet method, the film before the heat treatment contains a carbohydrate. The para-oriented aromatic polyamide as a main component forming the colored film of the present invention, which is a method for producing a para-oriented aromatic polyamide colored film characterized by being heat-treated at 300 ° C or more and 500 ° C or less, It consists essentially of units selected from the group consisting of:

-NH-Ar ₁ -NH- (1) -CO-Ar ₂ -CO- (2) -NH-Ar ₃ -CO- (3) wherein Ar ₁ , Ar ₂ and Ar ₃ are each at least 1
A divalent group containing two aromatic rings, and (1) and (2) are substantially equimolar when present in the polymer. In the present invention, in order to ensure good mechanical performance and dimensional stability, Ar ₁ , Ar ₂ , and Ar ₃ must each be a para-oriented group. Here, the para-oriented type means that the bonding direction of the main chain in the aromatic ring is located at the para-position, or the bonding direction of the main chains at both ends is coaxial or parallel in a residue composed of two or more aromatic rings. It means there is. A typical example of such a divalent aromatic group includes the following formula (1).

[0007]

Embedded image Here, X is _{-O -, - CH 2 -,} - SO 2 -, - S
-, -CO-. Further, some of the hydrogen atoms of these aromatic rings may be substituted with a halogen group, a nitro group, a sulfone group, an alkyl group, an alkoxy group, or the like. Ar ₁ , Ar _2, and Ar ₃ may be at least two types, and may be the same or different from each other.

[0008] The polymer used in the present invention can be produced from a diamine, a dicarboxylic acid, or an aminocarboxylic acid corresponding to each unit by a known method. Specifically, a method is used in which a carboxylic acid group is first derived into an acid halide, an acid imidazolide, an ester, and the like, and then reacted with an amino group. The type of polymerization is also called a low-temperature solution polymerization method, an interfacial polymerization method, or a melt polymerization method. And a solid phase polymerization method. In the aromatic polyamide used in the present invention, groups other than those described above may be copolymerized in an amount of about 10 mol% or less, or other polymers may be blended. The most typical aromatic polyamide used in the present invention is poly-p-phenylene terephthalamide (PPTA).

If the degree of polymerization of the aromatic polyamide used in the present invention is too low, it is not possible to obtain a film having good mechanical properties which is the object of the present invention. Therefore, the logarithmic viscosity ηinh of 3.5 or more is usually used in 100 ml of sulfuric acid. 0.2 g of polymer
Is dissolved and a value measured at 30 ° C.) is selected. The film of the present invention must have a Young's modulus in the longitudinal and width directions of 500 kg / mm ² or more in order to ensure good mechanical properties during processing and use.
It is preferably at least kg / mm ² . The film of the present invention is required to have an elongation of 8% or more in order to secure the handling property during processing and use.
% Is preferable. The coefficient of hygroscopic expansion of the film of the present invention needs to be 40 × 10 ⁻⁶ /% RH or less, preferably 35 × 10 ⁻⁶ /% RH or less, and more preferably 30 × 10 ⁻⁶ /% RH. It is more preferred that: Films having a coefficient of hygroscopic expansion of more than 40 × 10 ⁻⁶ /% RH cannot be used in applications requiring high dimensional accuracy, for example, in insulating substrate applications, because of the problem of large changes in the wiring pattern position due to humidity. .

The heat shrinkage of the film of the present invention is 0.2%
Or less, and more preferably 0.1% or less. A film having a large heat shrinkage has problems such as a permanent change in dimensions at the time of processing at a high temperature and a deviation from a design dimension. The dielectric breakdown voltage of the film of the present invention is 100 k for a film having a thickness of 40 to 50 μm.
v / mm or more is preferable, and 150 kv / mm or more is more preferable. The dielectric breakdown voltage is important when the film is used as an electric circuit board. If this value is low, a short circuit between wirings is likely to occur, and the performance is deteriorated.

The light transmittance of the film of the present invention is 5
Must be 40% or less at 30 nm, 40%
If it exceeds, sufficient light-shielding ability cannot be obtained. The light transmittance is more preferably 25% or less. When the light transmittance at a wavelength of 530 nm is low, the transmittance of the second high-long-wave laser of YAG used for processing semiconductors, liquid crystals, and the like is low. The feature is that the influence of can be avoided. Also,
When a film is used for repackaging, it also has a feature that the influence of light transmission to the inside can be avoided. The content of the alkali or alkaline earth metal in the film of the present invention is 1
It is preferably at most 000 ppm, more preferably at most 100 ppm. If a large amount of alkali or alkaline earth metal is present in the film, moisture absorption dimensional stability and electrical insulation often deteriorate, and in the present invention, a colored film having a low content of these metals may be used. This is a preferred embodiment.

The thickness of the film of the present invention is usually 3 μm or more and 100 μm or less, and more preferably 10 μm or more and 70 μm or less. The density of the colored film of the present invention is 1.38.
The above is preferable, and 1.40 or more is more preferable. The coloring component of the film of the present invention is mainly a film itself and a small amount of decomposition products of carbohydrates, and generally does not substantially contain coloring components such as dyes and pigments,
For this reason, the film is characterized by a relatively high density and a dense colored film. Next, a method for producing the aromatic polyamide colored film of the present invention will be described. Since para-oriented aromatic polyamide has a high melting point and cannot be melt-molded, a molded product solution dissolved in a solvent (hereinafter referred to as a dope)
Is used to form a film by a wet method, a dry method, or a dry-wet method. In the case of PPTA which is hardly soluble in an organic solvent, a polymer is dissolved in an inorganic strong acid such as concentrated sulfuric acid to form a dope, and a film is formed by a wet method.
As shown in the publication, a method of extruding once in a liquid crystal state, optically isotropic, and then solidifying is preferably used.
On the other hand, for example, in the case of an aromatic polyamide soluble in an organic solvent such as chloro-substituted PPTA, hydrochloric acid by-produced during polymerization is neutralized to form a polymerization reaction mixture as it is as a molding solution (hereinafter referred to as “dope”). Alternatively, a method of forming a film by a dry-wet method is preferably used.

The method of forming the dope into a film is not particularly limited in the practice of the present invention, and may be a method of extruding directly from a die into a coagulation bath, a method of once casting from a die onto an endless belt, There is a method in which a dope is coated thereon by a doctor knife or other methods, and then the solvent is evaporated on a belt or guided to a coagulation bath together with the belt for wet coagulation. After the film is formed in this manner, the film is washed with water, and then subjected to a neutralization treatment if an acid by-produced during polymerization or an acid used for dissolution remains.
If an acid is contained in the formed film, neutralization is preferably performed because drying and heat treatment cause deterioration in mechanical properties due to heating. Examples of the alkali used for neutralization include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, sodium hydrogen carbonate and the like.

The neutralized film is preferably treated with an aqueous carbon dioxide solution after removing excess alkali and inorganic salts formed by the neutralization by washing. By the treatment with the aqueous carbon dioxide solution, the alkali or alkaline earth metal ions bound to the terminal groups of the aromatic polyamide molecules can be removed, and the metal ion content in the film can be reduced. In the present invention, carbohydrate is contained in the film before heat treatment, and 300 ° C or more and 500 ° C or more.
Heat treatment must be performed at the following temperature. Here, the carbohydrate is a compound whose element ratio in the molecule is represented by the general formula Cm (H ₂ O) n, and includes glucose, fructose, mannose, galactose, tagatose, xylose, arabinose, ribulose, xylulose, Lyxose, ribose, monosaccharides such as deoxyribose, saccharose, maltose, cellobiose, gentiobiose, melibiose, lactose, turanose, sophorose, trehalose, isotrehalose, saccharose,
Disaccharides such as isosaccharose, cellulose, starch,
Glycogen, caronine, laminaran, dextran,
Polysaccharides of inulin, levan, mannan, xylan, gum arabic and the like can be mentioned. The cause of coloring due to the addition of carbohydrates is considered to be promotion of coloring due to thermal decomposition of the film itself and generation of coloring matter due to decomposition of carbohydrates, which is different from coloring with conventional dyes or pigments. In order to facilitate the impregnation into the film, a water-soluble carbohydrate is preferably used.

As a method for incorporating carbohydrates into a film, a method of adding a carbohydrate to a film-forming dope, a method of adding a carbohydrate to a coagulation bath, a method of bringing a film before or after drying into contact with a solution containing these carbohydrates. Examples include a method of impregnation, and a method in which the film after coagulation is washed with water, neutralized, and subjected to carbonic acid treatment, and then the wet film containing water is impregnated by contact with a carbohydrate aqueous solution, followed by drying and heat treatment. Can be The contact of the film with the solution can be performed by immersing the film in the solution or spraying and showering the solution on the film.
The solution concentration, temperature and contact time are determined according to the required content, but usually the solution concentration is 1 to 10% and the temperature is 10 ° C to
100 ° C., the contact time is in the range of 10 seconds to 20 minutes. The film thus obtained is dried, if necessary, after washing the solution adhering to the surface. If desired, the film can be stretched before drying. That is, the wet film before drying is moved from 1.01 to 1.01 in one or two directions.
By stretching the film about 1.4 times, the coefficient of hygroscopic expansion of the film can be reduced and the mechanical properties can be improved.

The drying of the film is preferably carried out under tension, under constant length or with slight stretching. As a method for carrying out such drying, for example, it can be fixed to a tenter dryer or a metal frame and dried. The drying temperature is usually
It is in the range of 100 ° C to 300 ° C. In the present invention, the dried film thus obtained is heated at 300 ° C. or higher.
Heat treatment must be performed at a temperature of 500 ° C. or less, and this heat treatment improves mechanical performance and dimensional stability and lowers light transmittance. The heat treatment can be performed under tension, under constant length, or in a relaxed state, and can be performed in two or more stages by a combination thereof.

If the heat treatment temperature is lower than 300 ° C., there are problems such as insufficient thermal decomposition of the added carbohydrate, insufficient light-shielding properties, and dimensional change due to thermal decomposition during use. On the other hand, when the temperature exceeds 500 ° C., the thermal decomposition of the aromatic polyamide proceeds, and the mechanical performance is greatly reduced. In the present invention, in order to obtain a colored film having good mechanical performance, dimensional stability, and light transmittance, it is necessary to select appropriate conditions as a heat treatment temperature and a heat treatment time. Not less than 450 ° C. and heat treatment time is not less than 10 seconds and not more than 100
Seconds or less are preferably used.

BEST MODE FOR CARRYING OUT THE INVENTION In order to facilitate understanding of embodiments of the present invention and effects of the present invention, typical PPTA is selected as para-aramid, and examples are shown below. These examples illustrate the present invention. It is not limited. Further, it will be easily understood that the effects of the present invention will be similarly obtained in other para-oriented aromatic para-aramids. In the examples, unless otherwise specified, parts by weight or% by weight are indicated.

The logarithmic viscosity ηinh is 98% sulfuric acid 100 ml
0.2 g of the polymer was dissolved in the solution and measured at 30 ° C. by a conventional method. The viscosity of the dope was measured using a B-type viscometer at a rotation speed of 0.5 rpm. The thickness of the film was measured with a dial gauge having a measurement surface having a diameter of 2 mm.
The elongation and Young's modulus of a sample of 200 mm × 10 mm were measured using a constant-speed elongation type elongation tester and the measurement length was 1 unit.
It was measured at 00 mm and a tensile speed of 50 mm / min. The coefficient of hygroscopic expansion is 50 mm × 10 mm (measurement length 40
mm) in a sample with a size of 20 mm in an air oven.
From the length (L ₀ ) measured by drying the film at 0 ° C. for 2 hours and the length (L ₁ ) of the film measured by absorbing moisture sufficiently at 23 ° C. and 55% RH, the coefficient of hygroscopic expansion = (L ₁₋ L ₀ ) / L ₀ ÷ 55 (% RH). The dimensions of the film were measured with a measuring microscope (OLYM
(Manufactured by PUS).

The heat shrinkage is 2 cm × 5 cm from the film.
Was cut out with a knife at 4 cm intervals to form a label. After leaving in advance in an atmosphere of 23 ° C. and 55% RH for 72 hours, the distance between the labels was read and measured with a microscope. The sample was left in a hot-air oven at 2 ° C. for 2 hours without restraint, and then left again in an atmosphere of 23 ° C. and 55% RH for 72 hours. The distance between the labels was read and measured with a microscope. The density was measured at 30 ° C. by a density gradient tube method using carbon tetrachloride-toluene. The dielectric breakdown voltage was measured by applying a 60 Hz alternating current from a 6 mm diameter electrode to a 100 mm × 100 mm film sample. The metal ion content in the film is
It was measured by an inductively coupled plasma emission analyzer (ICAR-575-II, manufactured by Nippon Jarrell Ash). The light transmittance was measured at a wavelength of 530 nm using a spectrophotometer (Model 6B manufactured by Hiranuma Sangyo).

Reference Example-Production of PPTA PPTA was obtained by the low temperature solution polymerization method as follows. Tokiko Sho 53-4
Dissolve 70 parts of anhydrous lithium chloride in 1000 parts of N-methylpyrrolidone in a polymerization apparatus shown in
Then, 48.6 parts of paraphenylenediamine were dissolved.
After cooling to 8 ° C., terephthalic acid dichloride 91.4
Parts were added at once in powder form. After a few minutes, the polymerization reaction product solidified in a cheese-like manner. Therefore, the polymerization reaction product was discharged from the polymerization apparatus according to the method described in Japanese Patent Publication No. 53-43986, immediately transferred to a twin-screw closed kneader, and polymerized in the kneader. The reaction was milled. Next, the finely pulverized product was transferred into a Henschel mixer, to which an approximately equal amount of water was added and further pulverized, filtered, washed several times in warm water, and dried in hot air at 110 ° C. 95 parts of a pale yellow polymer having ηinh of 6.1 were obtained.

[0021]

【Example】

Example 1 ηinh of the above reference example was 6.
Is dissolved at 60 ° C. and the polymer concentration is 12
% Stock solutions were prepared. When the viscosity of this stock solution was measured at 60 ° C., it was 4800 poise. This stock solution had optical anisotropy. This stock solution was degassed under vacuum while maintaining the temperature at 60 ° C. The dope was passed from a tank through a filter, fed by a gear pump, and a dope was cast from a T-die having a slit of 0.4 mm × 700 mm onto a tantalum belt polished to a mirror surface, with a relative humidity of about 25% and a temperature of about 120.
The casting dope was optically isotropic by blowing air at a temperature of ° C, and was introduced into a 57% aqueous sulfuric acid solution at 15 ° C together with a belt to solidify it. Next, the coagulated film was peeled off from the belt, washed in room temperature water for 6 minutes, then in a 2.0% by weight aqueous sodium hydroxide solution for 6 minutes, and further run in room temperature water for 6 minutes. 0.01% aqueous solution (pH =
4.5) was run for 12 minutes. Furthermore, 1% of 60 degrees Celsius
Run in a soluble starch aqueous solution for 10 minutes and
Washed for minutes. After washing, the film is roll-stretched in a 1.02-fold elongate direction (hereinafter abbreviated as MD direction), then stretched in a width direction (TD direction) with a 1.08-fold tenter, and then fixed while being sandwiched between the tenters. At 200 ° C (hot air)
Further, the film was heat-treated at a constant length on a hot plate at 400 ° C. for 30 seconds while sandwiched between tenters, then heat-treated at 280 ° C. in a relaxed state, and then a film having a thickness of 50 μm and a width of 508 mm was wound up.

The density of the obtained film is 1.41, and the Young's modulus in the longitudinal and width directions is 1110 kg each.
/ Mm ² , 1100 kg / mm ² , elongation of 16.
8%, 16.7%, and the coefficient of hygroscopic expansion is 28 × 10 ⁻⁶ each.
/% RH, 29 × 10 ⁻⁶ /% RH, heat shrinkage rates of 0.08% and 0.08%, respectively, and dielectric breakdown voltage of 189 kv /
mm and sodium ions as metal ions
ppm. The light transmittance at 530 nm of the film was 9.8%.

Comparative Example 1 The procedure of Example 1 was repeated, except that the sample was run in a 4% aqueous solution of an acid dye nylon black GL (trade name) manufactured by Mitsui Toatsu instead of the 1% aqueous starch solution. A PPTA film was produced in exactly the same way. The density of the obtained film was 1.39, and the Young's modulus in the longitudinal and width directions was 1090 kg / mm ² and 1150 kg /
mm ² , elongation is 49.2% and 49.5%, respectively, and the coefficient of hygroscopic expansion is 46 × 10 ⁻⁶ /% RH and 44 × 10, respectively.
⁻⁶ /% RH and heat shrinkage are 0.14% and 0.1, respectively.
3%, the breakdown voltage was 97 kv / mm, and sodium ion was included as metal ions at 4800 ppm. The light transmittance at 530 nm of the film was 1% or less. This film has a low light transmittance and a sufficient light-shielding property, but has a high coefficient of hygroscopic expansion and insufficient dimensional stability.

Comparative Example 2 A PPTA film was produced in exactly the same manner as in Example 1 except that the sample was not run in a 1% aqueous starch solution. The density of the obtained film is 1.41
And the Young's modulus in the longitudinal and width directions is 1120, respectively.
^{kg / mm 2, 1130kg / mm} 2, respectively elongation 3
2.3%, 28.9%, and the coefficient of hygroscopic expansion is 31 × 1 each.
0 ⁻⁶ /% RH, 33 × 10 ⁻⁶ /% RH, heat shrinkage rates of 0.06% and 0.05%, respectively, and dielectric breakdown voltage of 17
It was 1 kv / mm, and contained 45 ppm of sodium ions as metal ions. The light transmittance at 530 nm of the film was 63%. This film is
It has a high light transmittance and is unsuitable for applications requiring light shielding.

Examples 2 to 6 and Comparative Examples 3 and 4 A film obtained by running the aqueous solution of carbon dioxide in Example 1 was wound up in a wet state and cut out, and subjected to the following experiment. The film was cut into a size of about 14 cm × 28 cm, immersed in a compound described in Table 1 at 60 ° C. for 5 minutes, washed with water, and sandwiched between stainless steel molds to shrink the film. To prevent
After drying in a hot-air oven at 400 ° C., heat treatment was performed in a hot-air oven at 400 ° C. for 1 minute, and after removing from the mold, heat treatment was performed in a hot-air oven at 320 ° C. for 1 minute. The properties of the obtained film are shown in Table 1 below.

[0026]

[Table 1] Examples 2 to 6 are films of the present invention,
It is a colored film with excellent moisture absorption dimensional stability and electrical insulation.

On the other hand, Comparative Example 3 is a film dyed with an acid dye, and has a large coefficient of hygroscopic expansion and a low dielectric breakdown voltage. Comparative Example 4 is a film produced without adding a carbohydrate, and has a high light transmittance and an insufficient light-shielding property. Comparative Example 5 In Example 1, the coagulated film peeled off from the belt was cut out, washed with water for 10 minutes, cut out into a size of about 14 cm × 28 cm, and contracted by being sandwiched between stainless steel molds. Dried in a hot air oven at 200 ° C., heat-treated in a hot air oven at 400 ° C. for 1 minute, and then removed from the mold.
Heat treatment was performed in a hot air oven at 0 ° C. for 1 minute. The density of the obtained film was 1.42, the Young's modulus in the longitudinal direction was 1160 kg / mm ² , the elongation was 1.2%, the hygroscopic expansion was 33 × 10 ⁻⁶ /% RH, and the heat shrinkage was respectively 0.05
%, Dielectric breakdown voltage was 146 kv / mm, and the content of metal ions was 5 ppm or less. 530 of film
The light transmittance in nm was 35%. This film is colored by residual sulfuric acid during film formation, but has extremely low elongation, is difficult to handle, and is not practical.

[0028]

The film of the present invention is a colored film in which good mechanical performance, heat resistance and dimensional stability of a para-oriented aromatic polyamide film are not impaired, and a colored film produced by a conventional method. It has a lower coefficient of hygroscopic expansion and higher dielectric breakdown voltage than films. Therefore, as a feature in using the product, for example, when a film is used for re-sheathing, there is a feature that it is possible to avoid the influence of light rays on internal components and to prevent the internal structure from being exposed to the outside.
On the other hand, as a feature in film processing, when an element or the like formed on the film surface is optically processed, transmission of a light beam used for processing to the back surface can be avoided. Taking advantage of these features, flexible printed wiring boards (FP
C), Tape automated bonding (TAB)
Insulating substrate such as carrier tape for speaker, speaker diaphragm,
It can be used as an acoustic member such as a voice coil, a solar cell substrate, and the like.

Claims (3)

[Claims] 1. A film comprising a para-oriented aromatic polyamide having a logarithmic viscosity of 3.5 or more as a main component,
The film has a Young's modulus of 500 in both the longitudinal and width directions.
kg / mm ² or more, elongation 8% or more, moisture expansion coefficient 4
An aromatic polyamide colored film having a light transmittance of 0 × 10 ⁻⁶ /% RH or less and a light transmittance at 530 nm of 40% or less. 2. The aromatic polyamide colored film according to claim 1, wherein the content of the alkali or alkaline earth metal in the film is 1000 ppm or less. 3. When forming a para-oriented aromatic polyamide film by a wet method, a dry method, or a dry-wet method, a film before heat treatment contains carbohydrate and then heat-treated at 300 ° C. or more and 500 ° C. or less. A method for producing a para-oriented aromatic polyamide colored film, characterized by the following.