JPH03120043A - Aromatic polyamide film and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain high strength and high modulus by composing of specific para-oriented type aromatic polyimide-amide, and incorporating predetermined content of chemically precipitated metal compound on one side or in the interior of a film. CONSTITUTION:Para-oriented type aromatic polyimide-amide having substantially 2.5 or more of logarithmic viscosity etainh is contained, and chemically precipitated metal compound is contained at least 1wt.% to total weight of the film on one side surface or in the interior of a film. Here, the para-oriented type means that bond for growing molecular chain is disposed coaxially with or in parallel with opposite aromatic group of aromatic nucleus. Such bivalent aromatic group includes, for example, paraphenylene, 4,4'-phenylene, 1,4- naphthylene, 2,5-pyridine, etc. Thus, desirable mechanical properties represented by high strength and high modulus are obtained, and metal or its compound is precipitated in or/and on the surface of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a film made of para-oriented aromatic polyamide in which a metal or a compound thereof is chemically precipitated inside and outside, and a method for producing the film.

[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. In addition, several examples of molding PPTA into films have been proposed (for example, Japanese Patent Publication No. 4521/1983, Japanese Patent Publication No. 7/17886, etc.).

In recent years, several methods have been reported in which a conductive metal such as copper is directly laminated onto a plastic film by methods such as sputtering or ion blating without using an adhesive. No technology has yet been disclosed for chemically depositing a metal or its compound inside or outside of a para-oriented aromatic polyamide film.

[Problem to be solved by the invention]

An object of the present invention is to provide a para-oriented aromatic polyamide film having high strength and high modulus and containing a metal or a compound thereof, and a method for producing the same.

[Means to solve the problem]

As a result of extensive research on how to obtain such a film, the inventors of the present invention formed an optically anisotropic dope of para-oriented aromatic polyamide onto a film on a supporting surface.
The film exhibits excellent mechanical properties through a special method in which it is coagulated, then brought into contact with a liquid containing more than 50 weight of water obtained by removing the solvent, or a liquid containing an organic solvent. The inventors discovered that it was possible to obtain a film in which metals or their compounds were freely precipitated, and after further research they completed the present invention.

That is, the first aspect of the present invention is that the film is made of a substantially para-oriented aromatic polyamide having a logarithmic viscosity ηinh of 2.5 or more, and a chemically precipitated metal compound is added to at least one surface or inside of the film based on the total weight of the film. A para-oriented aromatic polyamide film containing at least 1% by weight.

The second aspect of the present invention is a para-oriented aromatic polyamide having a logarithmic viscosity (ηinh) of 2.5 or more and at least one member selected from the group consisting of concentrated sulfuric acid, chlorosulfuric acid, and fluorosulfuric acid with a concentration of 96% by weight or more. An optically anisotropic dope containing a solvent is formed into a film on a support surface while maintaining its optical anisotropy, and the dope is substantially converted into an optically isotropic dope by moisture absorption and/or heating. Leave it until it solidifies,
A method for producing a para-oriented aromatic polyamide film, which comprises contacting a film containing 50% by weight or more of water or an organic solvent obtained by substantially removing a solvent with an electroless plating solution.

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 + N H---(r) COA
r2 CO---(II)N HArz
C0------(I[I) where Art,
Arz and A r 3 are each a divalent aromatic group,
(1) and (II) when present in the polymer are substantially equimolar.

In the polyamide film of the present invention, in order to ensure good mechanical performance, A r 1 , A r 2 and Ar are each so-called para-oriented groups.

Here, the para-oriented type means that the bonds that grow the molecular chain are located coaxially or parallel to the opposite direction 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-pyridazine. They may be substituted one or more with non-reactive groups such as halogen, lower alkyl, nitro, methoxy, sulfonic acid, cyan groups, etc. Ar, , Art and A r 3
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.

In the present invention, if the degree of polymerization of the aromatic polyamide is too low, it will not be possible to obtain a film with good mechanical properties, which is the object of the present invention. (value measured at 30°C by dissolving 0.5 g of polymer in 100 d of sulfuric acid) is selected.

The films obtained according to the invention generally have at least 1.37
It has a density of at least 1.39 g/c1i, more preferably at least 1.39 g/ca. This is the density necessary to ensure the mechanical properties of the film mentioned above.

The film obtained by the present invention usually has an initial modulus (Young's modulus) of at least 500 kg/mu'', more preferably at least 700 kg/1111''.

The film of the present invention contains at least 1% by weight or more, preferably 5% to 20% by weight of a metal or its compound based on the total weight of the film, and the metal or its compound is chemically precipitated. Metals that need to be solid include Pt, Ag, Au, Pd, and Cu.

Ni, Co, etc. are mainly used, but are not limited to them.

Preferably, the metal is deposited as particles having a diameter on the order of 500 nm.

Examples of the metal compound include oxides of the above metals, and metals and metal compounds may coexist.

Next, a method for manufacturing the film of the present invention 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, 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 weight or less, and preferably 16 weight or less for PPTA with particularly high ηinh.

The dope used in the present invention may contain additives such as extenders, anti-glare agents, 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 purchased.

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.

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

In order to convert from optical anisotropy to optical isotropy, the optically anisotropic dope formed into a film on the supporting surface must be made to absorb moisture and reduce the concentration of the bath agent that forms the dope prior to solidification. , the dope can be transformed into an optically isotropic region by changing the solubility of the solvent and the polymer concentration, or the temperature of the dope can be raised by heating, and the dope can be transformed into an optically isotropic region simultaneously or sequentially, or by heating and This can be achieved by using moisture absorption in combination.

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 be used at temperatures above 45° C., 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 the upper limit is, considering the decomposability of the polymer.
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 a 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
Water-based liquids such as 0% by weight or less sodium chloride aqueous solution and calcium chloride aqueous solution, acetone, methanol,
These are organic solvents or aqueous solutions of organic solvents such as ethanol, ethylene glycol, dimethylformamide, and N-methylpyrrolidone. 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. The film may also be cleaned with an organic solvent. The cleaning may be carried out by, for example, running the film in a cleaning liquid or spraying the cleaning liquid.

In the present invention, the method of containing an organic solvent of 50 weight or more includes a method of coagulating in an organic solvent bath, then washing with an organic solvent, and a method of coagulating in an aqueous bath, then containing the organic solvent. Preferred methods include a method in which the organic solvent is added while washing, and a method in which the organic solvent is substituted after coagulating and washing in an aqueous system.

In the present invention, the film thus containing water or an organic solvent must be brought into contact with an electroless plating solution.

If the content of water or organic solvent is less than 50% by weight, the diffusion rate of the electroless plating solution will be significantly reduced, making it impossible to deposit the metal or its compound inside.

Pt is used as a metal salt in the electroless plating solution of the present invention.

It is mainly used as a solution containing Ag, Au, Pd, Ca, Ni, Co, etc. Also, even if it is an alloy, it is not often specified.

As the reducing agent, formalin, hypophosphorous acid, etc. are mainly used, but these are not specified.

Further, the electroless plating solution of the present invention contains formate, acetate, etc. as a buffering agent.

The method of contacting with the electroless solution of the present invention is: 1) Immersion in a solution consisting of a metal salt, a reducing agent, and a buffer; 2) A method in which the metal salt is pre-impregnated and then immersed in a reducing agent solution; 2) Impregnation with a reducing agent. Two methods are useful: (2) impregnating one side of the film with a metal salt and the other side with a reducing agent.

In the present invention, as the organic solvent, for example, dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, 2pyrrolidone, acetonitrile, acetone, methanol, ethanol, propatool, ethylene glycol, etc. can be used.

When drying the film thus obtained, it can also be stretched prior to drying if desired. That is,
1.01 in one or two directions of wet film before drying
By stretching the film by about 1.4 times, the mechanical properties of the film can be improved.

The film must be dried under tension, at a constant length, or slightly stretched while limiting shrinkage of the film. 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. Moreover, it can also be molded by hot press.

(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, unless otherwise specified, weight percentage or weight % is indicated.

Logarithmic viscosity (η1nh) was measured by dissolving 0.2 g of polymer in 100 ml of 98% sulfuric acid at 30"C in a conventional manner.

The viscosity of the dope was measured using a B-type viscometer at a rotation speed of 1 rpn+. The thickness of the film was measured using a dial gauge with a measuring surface of 2 mm in diameter. The strength elongation and modulus are determined by cutting a film sample into a rectangle of 100 mm x 10 (Incorporated) using a constant speed extension type strength elongation measuring machine, and applying a load at an initial grip length of 30 strokes and a tensile speed of 30 an/min.
The elongation curve was drawn five times and calculated from this.

The content of metals or their compounds is calculated by subtracting the weight of a film of the same size that does not contain metals or its compounds from the weight of a film that does not contain metals or its compounds. It was calculated by dividing by the weight of a film of the same size.

Example 1 A PPTA polymer having an ηinl+ of 5.5 was dissolved in 99.7% sulfuric acid at a polymer concentration of 12.0% to obtain an optically anisotropic dope 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. This case also had optical anisotropy as described above, and the viscosity was 4200 voids. This dope is passed through a filter from the tank, passed through a gear pump while keeping it at about 70°C, and then passed through a 1.5m curved pipe to a die, and from a die with a 0.3m x 300mm slit, it is poured into Hastelloy, which has been polished to a mirror finish. After blowing air at about 90°C with a relative humidity of 95% onto the cast dope to achieve optical equality, hold it on the belt for about 1 minute, and then cast it at 0° with the belt. It was introduced into a 20% by weight aqueous sulfuric acid solution of C and coagulated. The coagulated film is then peeled off from the belt and passed through rotating rollers at approximately 20°.
A gel-like coagulated film having a moisture content of about 400% by weight was obtained by running the film in a water tank (retention time: about 3 minutes).

This film was brought into contact with an electroless silver plating bath (see 2-4 in Table 2) at 25°C to precipitate silver inside and on the surface of the film to obtain a film. After washing the obtained film with a large amount of water, it was sandwiched between two stainless steel frames of about 10 cm x 15 cm, and dried at a fixed length in an air oven maintained at 200'C. Since the silver on this film is also contained inside, it is impossible to separate the silver and PPTA without destroying the film, probably because of the anchor effect.
No phase separation with PPTA was observed during drying.

Example 2 A gel-like coagulated film obtained in the same manner as in Example 1 was immersed for 20 minutes in a mixed solution of 6.7 g/Il of -dannitric acid SN and 6.4 rnl/l of 28% aqueous ammonia, and then soaked in 50 d of formamide. //! A film was obtained by immersing it in a solution.

When this film was washed with a large amount of water and dried under the same conditions as in Example 1, no phase separation between PPTA and silver was observed during drying, and a film containing silver inside and on the surface was obtained. .

Examples 3 to 5 A gel coagulation film obtained in the same manner as in Example 1 was subjected to an electroless copper plating bath (Example 3) and an electroless gold plating bath (using a hydrogenated elementary compound reduction bath: Example 4) ), and was contacted and dried in an electroless cobalt plating bath (Example 5) under the same conditions as in Example 1 to obtain a metal-containing film. In all cases, no phase separation between the metal and PPTA was observed when dry.

Comparative Example 1 The gel-like coagulated film obtained in Example 1 was once heated to 120"
After drying with C to a moisture content of about 30% by weight, the film was brought into contact with an electroless plating solution under the conditions shown in Example 1 to obtain a film. This film had silver slightly attached only to the surface, and no silver precipitation was observed inside, making it easy to remove the silver.

In addition, silver was partially exposed when the PPTA expanded and contracted during drying and cooling.

Example 6 The silver-containing film obtained in Example 1 was unidirectionally 1.
A film was obtained which was stretched twice and dried at 200°C. As in Example 1, no silver flaking was observed in the obtained film.

Comparative Example 2 When the film obtained in Comparative Example 1 was dried in the same manner as in Example G, the silver was removed.

The processing conditions and physical properties of these films are summarized in Table 1. Further, general examples of electroless plating solutions are shown in Table 2.

(Left below) (2-3) * Immediately before plating, mix liquid A and liquid B at a ratio of 9:1 to form a bath.

〔Effect of the invention〕

The film produced by the method of the present invention has good mechanical properties represented by high strength and high modulus, and metals or compounds thereof are precipitated inside and/or on the surface of the film.

Films produced by the method of the invention have good mechanical properties and good heat resistance.

Taking advantage of these performance characteristics, the film according to the present invention is useful for insulators for capacitors, speakers, diaphragms, tapes for thermal transfer printers, flexible printed wiring boards, photographic films, etc. It can be used as a colored tape or sheet by taking advantage of its characteristics, and is also useful as a packaging material, electromagnetic shielding material, etc.

Claims (2)

[Claims] (1) Made of substantially para-oriented aromatic polyamide with a logarithmic viscosity ηinh of 2.5 or more, containing at least 1% by weight of a chemically precipitated metal compound on at least one side or inside the film based on the total weight of the film. A para-oriented aromatic polyamide film characterized by: (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. An optically anisotropic dope comprising the above was formed into a film on a support surface while maintaining its optical anisotropy, and left until the dope was substantially converted into an optically isotropic dope by moisture absorption and/or heating. A method for producing a para-oriented aromatic polyamide film, which comprises contacting an electroless plating solution with a film containing 50% by weight or more of water or an organic solvent obtained by post-solidifying and substantially removing the solvent. .