JPH0284328A - Metallized film - Google Patents

Abstract

PURPOSE:To markedly reduce a capacity change as compared with a conventional known metallized film by providing a metal membrane to a film composed of substantially para-oriented aromatic polyamide having properties such that a coefficient of thermal expansion, a thermal shrinkage factor, a coefficient of hygroscopic expansion and a coefficient of moisture absorption are respectively specific values and a logarithmic viscosity is also a specific value. CONSTITUTION:A film to be used has properties such that a coefficient of thermal expansion is (0-15)X10<-6>mm/mm/ deg.C at 25-250 deg.C, a thermal shrinkage factor is 0.1% or less at 250 deg.C, a coefficient of hygroscopic expansion is 30X10<-6>mm/mm/% RH or less at 25 deg.C and a coefficient of moisture absorption is 25wt.% or less at 25 deg.C and 50% RH. When a metal membrane is provided to this film or a metallized film is prepared using this film, the kind of a metal is not especially limited and the metal membrane is adhered to the film according to a conventional method, for example, a vacuum vapor deposition method or an ion plating method.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to poly(p-phenylene terephthalamide) (
The present invention relates to a metallized film in which a thin metal film is provided on a heat-resistant film with excellent dimensional stability made essentially of PPTA (hereinafter referred to as PPTA).

[Conventional technology]

Para-oriented aromatic polyamide has particularly excellent crystallinity and high melting point, and due to its rigid molecular structure, it has heat resistance and high mechanical strength, and has been attracting particular attention in recent years. It is a molecular material.

A method for producing a film from a para-oriented aromatic polyamide containing PPTA is described, for example, in Japanese Patent Publication No. 57-17886.
This method is disclosed in Japanese Patent Publication No. 2003-100003, and is a method in which an optically anisotropic dope is phase-exchanged with an optically isotropic dope and solidified. However, it has been found that the film produced by this method is still insufficient in terms of dimensional stability. for example,
Expansion due to moisture absorption is quite large, and thermal contraction rate is also large, so so-called metallized films, in which a thin metal film is provided on the film surface by methods such as vapor deposition or sputtering, may peel off, warp, or warp due to changes in the environment. It was found that deformations such as waving occurred. and,
These problems can be said to be common to all conventionally known PPTA films.

On the other hand, attempts to improve the moisture absorption properties of para-oriented aromatic polyamide films have been disclosed, for example, in Japanese Patent Publication No. 5,646,421. This publication describes an aromatic polyamide film in which aromatic groups are substituted with chlorine, and it appears that the moisture absorption dimensional stability increases due to the effect of the introduced chlorine atoms. However, since the thermal dimensional stability is rather reduced, the above-mentioned problem occurs when metallized at high temperatures. Furthermore, at high temperatures, the metal thin film is corroded due to the corrosive nature of the introduced chlorine atoms.

[Problem to be solved by the invention]

The object of the present invention is to provide a P that has excellent mechanical properties, performance and heat resistance.
The object of the present invention is to provide a metallized film using a PTA-based polymer that has excellent dimensional stability against both heat and humidity.

[Means to solve the problem]

The present inventors have made the following findings as a result of extensive research to obtain a PPTA film that meets the above objectives. That is, by the method disclosed in Japanese Patent Publication No. Sho 57-17886, in which an optically anisotropic dope of para-oriented aromatic polyamide is first prepared and then solidified by optical isostatic ratio,
In the method of obtaining a transparent film with excellent mechanical performance, the crystallinity and molecular chain orientation of the film are increased by drying at high temperature without shrinkage, and then the drying temperature is slightly lower than the drying temperature. By heat-setting at high temperatures, a film with extremely excellent dimensional stability against heat, humidity, and external forces can be obtained, and since this film has an extremely small coefficient of thermal expansion, dimensional changes are small (all-thickness thin film). The present invention was achieved by discovering the fact that deformation such as curling due to heat is less likely to occur when laminated together, and as a result of further research based on these findings.

The present invention is a film made of a substantially para-oriented aromatic polyamide having a logarithmic viscosity of 3.5 or more, and having a coefficient of thermal expansion from 25°C to 250"C (0 to 15)XIO-
'Torso/Kan/'Heat shrinkage rate at C1250℃ is 0.1%
Below, the hygroscopic expansion coefficient at 25°C is 30 x 10-
6fflIIl/mm/%RH or less and 25°C 150
A metallized film having a moisture absorption rate of 2.5% by weight or less at %RH and having a metal thin film provided on at least one surface of the film.

PPTA used in the present invention is a polymer substantially represented by the formula, and is conveniently produced from conventionally known paraphenylenediamine and terephthaloyl chloride by a low-temperature solution polymerization method. In the present invention, a small amount of other components may be copolymerized or blended within a range that does not impair the effects of the present invention. Such examples include methanephenylene, 4,4'-diphenylene,
Examples include aromatic polyamides having skeletons such as 4,41-diphenylene ether and 3,4-diphenylene ether, and PPTA in which aromatic rings are substituted with alkyl or nitro groups.

If the degree of polymerization of the polymer of the present invention is too low, a film with good mechanical properties cannot be obtained, so the logarithmic viscosity η1nh (100 m
j! A polymer having a degree of polymerization that gives a value measured at 30° C. by dissolving 0.5 g of polymer is selected.

The film used in the metallized film of the present invention should meet the requirements set forth below.

First of all, the coefficient of thermal expansion of the film used in the present invention is measured in the range of 25 to 250°C (0 to 15)
It is within the range of 10-'mn+/mm/'C. Having a coefficient of thermal expansion in this range means 250
This means that the length remains almost the same even when heated to a temperature of up to 30°F.And this number is in the range from that of ceramics to that of metals. Films with excellent dimensional stability against heat can be produced by preventing shrinkage during drying to maintain a high level of planar orientation of molecular chains, and by drying or heat treatment at 300°C or higher to increase crystallinity. This is achieved for the first time by
When used at high temperatures, especially as a laminate with ceramics or metals, in applications with high temperatures or large temperature differences, for example, the film of the present invention does not curl at all, and the characteristics of the film of the present invention are fully exhibited. Become.

Second, the film used in the present invention has a heat shrinkage rate of 0.1% or less at 250''C.As the heat shrinkage rate of the film used in the present invention is extremely small, there are currently no heat-resistant films. It is superior to polyimide film, which has a large market share.The heat shrinkage rate is preferably 0.05% or less.A film with an extremely low heat shrinkage rate has improved orientation and crystallinity by drying or heat treatment. It is obtained by heat setting the film under no tension or under low tension at a temperature which is slightly lower than the drying or heat treatment temperature but above 260° C. without substantially reducing the temperature.

Thirdly, the film used in the present invention has a hygroscopic expansion coefficient at 25°C of 30 x 10-'m+a/ IIfl
lI/%RH or less, preferably 20 x 10-”tr
m/as/%RH or less. In this way, the characteristic of small dimensional changes due to moisture absorption is important for metallized films to exhibit a certain level of performance and function, regardless of the seasonal difference between hot and humid summers and low humidity and dry winters. Such properties are achieved by ensuring high crystallinity and orientation through drying or heat treatment at high temperatures.

Furthermore, the film used in the present invention is
The moisture absorption rate at %RH is 2.5% by weight or less. Such properties are obtained by uniquely high crystallinity due to high temperature drying or heat treatment. Films with a moisture absorption rate greater than 2.5% by weight have the disadvantage that they are difficult to process, such as vapor deposition, and their electrical properties (such as insulation resistance and dielectric constant) vary significantly, making them less useful for electrical applications. will decrease.

The film used in the present invention should further have a Young's modulus in all directions of 700 kg/mm" or more,
More preferably Young's modulus in all directions is 800 kg
/mm” or more. This feature is related to dimensional stability against mechanical external forces.Such a large puffiness ratio requires effective stretching after water washing and before drying in film production. This can be easily achieved by applying

In addition to the above-mentioned essential requirements, the film used in the present invention preferably has the following characteristics.

The film used in the present invention preferably has extremely high transparency. High transparency, e.g. 600nm
The transmittance of visible light having a wavelength of preferably 55% or more, more preferably 70% or more.

Furthermore, the film used in the present invention is preferably substantially void-free.

Furthermore, the film of the present invention typically has a density of 1.3
It is in the range of 70 to 1.410 g/d. This density value was determined by the density gradient tube method using carbon tetrachloride-toluene.
Measured at 0°C.

This density range is 1 to 4 that of known PPTA fibers.
This value is considerably smaller than the range of 3 g/cl to 1.46 g/Cd. The density is 1.370g
/ cJ When it becomes ungrooved, the mechanical properties decrease, 1.410
If it exceeds g/cffl, it becomes unstable and therefore tends to result in a film with impaired toughness.In any case, since the density is thus low, a light and high-strength film can be obtained.

The film used in the present invention preferably has plane orientation defined by the crystal orientation angle determined by X-ray diffraction as described below. That is, the crystal orientation angle regarding the 2θ-23° peak due to X-rays incident at right angles to the film surface is 30° or more, and the crystal orientation angle regarding the 2θζ18° peak due to X-rays incident parallel to the film surface is 60'. It is preferable that it is below.

There are two types of incident X-rays: when they are incident at right angles to the film surface (hereinafter referred to as the TV direction), and when they are incident parallel to the surface (hereinafter referred to as the TV direction).
(hereinafter referred to as SV force direction).

The film of the present invention has 2θ!
= i It has a large diffraction peak at 23°, but this 2θ':
The crystal orientation angle at 23° is preferably 30' or more, more preferably 50' or more. Further, a large diffraction peak of 2θ': 18° appears on the equator line due to the incidence in the S∙ force direction, but it is preferable that the crystal orientation angle at 2θ-18@ is 6°0° or less.

When both of these crystal orientation angles are satisfied, it can be said that the film of the present invention has a so-called plane-oriented structure, and the film has high mechanical properties t (for example, strength , elongation, Young's modulus)
It is very preferable because it has a high tear strength and a high tear strength. And in this respect,
It can be clearly distinguished from the "film" disclosed in the publication.

A known method can be used to measure the crystal orientation angle, and for example, the following method is used.

Place the counter at a predetermined 2θ angle and rotate the film 180°.
By rotating, a diffraction intensity curve is obtained.

In addition, for TVs, centering on the highest intensity, 90 degrees in front and back
Rotate between. The arc length in the diffraction photograph corresponding to the point showing half the intensity of the highest intensity of this curve with respect to the baseline drawn between the lowest intensity points is expressed in degrees (I
IL (i.e. 5 relative to the highest intensity baseline)
The angle relative to the 0% point) is measured and is taken as the crystal orientation angle of the sample. In the measurement, the diffraction intensity can be measured by stacking several films if necessary.

Next, a method for obtaining such a film will be described.

For this purpose, it is first necessary to prepare an optically anisotropic dope of a polymer consisting essentially of PPTA.

A suitable solvent for preparing the dope for forming the film is sulfuric acid at a concentration of 95% by weight or more. If the sulfuric acid content is less than 95%, dissolution may be difficult or the dope will have an abnormally high viscosity after dissolution. The dope of the present invention includes chlorosulfuric acid,
A small amount of fluorosulfuric acid, phosphorus pentoxide, trihalogenated acetic acid, etc. may be mixed. Although sulfuric acid can have a concentration of 100% by weight or more, a concentration of 97 to 100% by weight is preferably used from the viewpoint of stability and solubility of the polymer.

The polymer concentration in the dope is at least a concentration that exhibits optical anisotropy at room temperature (approximately 20 to 30° C.) or higher, and specifically is used at approximately 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.

The upper limit of the polymer concentration of the dope is not particularly limited, but it is usually 20% by weight or less, and for polymers with particularly high ηinh, 18% by weight or less is preferably used.
More preferably, it is 16 times or less.

The dope may be mixed with conventional additives such as fillers, deglapers, UV stabilizers, heat stabilizers, antioxidants, pigments, solubilizing agents, etc.

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,
It depends on the polymer 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 by changing the conditions for an optically isotropic dope, the optical It is possible to change from anisotropy to optical isotropy.

Prior to molding and solidifying the dope, it is preferable to remove as much insoluble dust, foreign matter, etc. as possible by filtration, etc., and to remove gases such as air generated or involved during melting. Deaeration can be performed after the dope is prepared, or can be achieved by performing it under vacuum (reduced pressure) from the stage of charging raw materials for preparation.

Preparation of the dope can be carried out continuously or batchwise.

The dope thus prepared is cast onto a supporting surface moving from a die, for example a slit die, while maintaining its optical anisotropy. The steps of casting and subsequent conversion to optical isotropy, coagulation, washing, stretching, drying, etc. are preferably carried out continuously, but if necessary, all or some of them may be carried out intermittently, i.e. It may be carried out batchwise.

The method for obtaining a transparent film with excellent mechanical properties used in the present invention is to cast a dope onto a supporting surface and then convert the dope from optically anisotropic to optically isotropic prior to solidification. .

To change optical anisotropy to optical isotropy, specifically, before solidifying an optically anisotropic dope cast on a support surface, the concentration of the solvent forming the dope is lowered by absorbing moisture. Transform the dope into an optically isotropic region by changing the solubility and polymer concentration, or increase the temperature of the dope by heating to transform the dope phase into an optically isotropic region, or simultaneously or sequentially absorb moisture and heat. This can be achieved by using them together.

In particular, methods using moisture absorption, including methods that use heating in combination, have a high optical isotropy ratio of optical anisotropy (and PPT
This is useful because it can be done without causing decomposition of A.

To make the dope absorb moisture, air at normal temperature and humidity may be used, but humidified or heated and humidified air is preferably used. The humidified air may contain atomized moisture exceeding the saturated vapor pressure, and may be so-called water vapor. However, supersaturated steam at a temperature of about 45° C. or lower is not preferred because it often contains large particles of condensed water. Moisture absorption is usually carried out with humidified air at room temperature to about 180°C, preferably 50 to 150°C.

In the case of a heating method, the heating means is not particularly limited;
Methods include applying humidified air to the casting dope as described above, irradiating with an infrared lamp, and using dielectric heating.

The optically isotropically cast dope on the support surface then undergoes solidification. For example, water, dilute sulfuric acid of up to about 70% by weight, aqueous sodium hydroxide and aqueous ammonia of up to about 20% by weight, sodium sulfate and aqueous sodium chloride solutions of up to about 10% by weight can be used to stop the dope from coagulating. and calcium chloride aqueous solution.

The temperature of the coagulating liquid is preferably 15°C or lower, more preferably 5°C or lower. This is because it has been found that, in general, the lower the temperature of the coagulating liquid, the less voids are included in the film.

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.

The cleaned film is then subjected to drying. Drying, that is, when a film is placed under no tension as the moisture content decreases, the film generally shrinks, but in obtaining the film used in the present invention, it is important that the film does not shrink during the drying process. Here, the expression "without shrinkage" should be understood to include drying with a constant length and drying with stretching. For example, an embodiment in which the film is stretched only in one direction and the length remains constant in the other direction is also allowed. Selection of the drying temperature is also important; drying should be carried out at an ambient temperature (T+'c) of 300°C or higher, or - after drying at an arbitrary temperature,
It is carried out by heat treatment at a temperature (ToC) of 0° C. or higher without shrinkage. Here, drying means removing moisture from the film, and the subsequent physical structure of the film (
For example, changing the crystalline state is called heat treatment.

In any case, it is necessary to fix the structure under tension at a temperature T of 300° C. or higher, thereby reducing the coefficient of thermal expansion and the coefficient of hygroscopic expansion, thereby suppressing moisture absorption.

After drying or heat treatment at a temperature T+ ("c") of 300°C or higher, 260.≦-T2-≦-T, -20' is satisfied.
It is also important to perform the heat treatment under no tension or under low tension at rz("c) of O to 0.8 kg/mm2.

This means that so-called heat setting is performed under substantially no tension, and this heat setting can reduce the thermal shrinkage rate and improve the tear resistance as a side effect.

To perform drying or heat treatment without causing the above-mentioned shrinkage, for example, use a method such as putting the material between tenters or metal frames and placing it in the open state.Drying under relaxed or low tension conditions can be done with the free end state in the open state. Tr
Tz≧50 (°C)) method, or by slightly narrowing the holding interval of the tenter. Other conditions related to drying and heat treatment are not particularly limited, and include methods using heated gas (air, nitrogen, argon, etc.) or room temperature gas, methods using radiant heat such as electric heaters and infrared lamps, dielectric heating methods, etc. The method can be freely selected, and one preferred embodiment is to run the film continuously throughout the entire process, but if desired, it may be partially carried out in a batch manner. Further, an oil agent, an identification dye, etc. may be added to the film in any step.

In the present invention, in order to obtain a film with excellent transparency, that is, extremely high light transmittance, in addition to the dope, moisture absorption gas, heating gas, supporting surface, coagulation liquid, cleaning liquid, drying gas, etc. It is preferable to reduce the content of dust and dirt in the film as much as possible, and in this respect, one preferred embodiment is to manufacture the film using so-called clean room or clean water.

The film of the present invention may contain dispersed inorganic substances such as silica, talc, and calcium sulfate as a smoothing agent.

In addition, the film used in the present invention may be made to facilitate adhesion, improve flatness, be colored, or
Various surface treatments and pretreatments may be performed for the purpose of preventing static electricity, imparting wear resistance, and the like.

Next, methods for producing metal thin films and metallized films will be described.

The type of metal in the metal thin film of the present invention is not particularly limited, and may be used as appropriate depending on the use of the metallized film. For example, for magnetic recording media, Co5Ni, C
r, Fe and their alloys, such as Co-Cr alloy, Co-Ni alloy, Co-Ni-Fe alloy, Co-Fe
Alloys, Co oxides (Coo nato), and alloys of these with trace amounts of P, 3T, B, Mn, Zn, etc., iron oxides, iron nitrides, iron hydroxides, iron sulfides, iron Carbonate compounds, etc., and specifically, Fed as an iron oxide.

Fe2O,, Fes 04, etc.; iron nitrides include Fez N, Fe, N, etc.; iron hydroxides include Fe(OH)z, Fe(OH)3,
FeoOH, etc., and iron sulfides include FeS, Fe
zS, etc., and as an iron carbonate compound, FeCox
, FeCO5・H! O etc. Also included are non-stoichiometric iron compounds with intermediate compositions other than those described herein. Further, materials for capacitors include aluminum, zinc, iron, titanium, nickel, and alloys thereof, but are not limited to these.

Further, for transparent conductive films, indium oxide, tin oxide, cadmium oxide, antimony oxide, zinc oxide, tungsten oxide, molybdenum oxide, or mixtures thereof, gold, palladium, or chromium-based alloys are used. Other options include silver, copper, tantalum, titanium,
Any metal such as titanium nitride may be used.

The method for depositing these metal thin films on the film may be any known method, such as vacuum evaporation, ion blating, sputtering, chemical vapor deposition, laser chemical vapor deposition, plasma evaporation, or plating deposition. method, electroless plating method, or a suitable combination thereof.

The thickness of the metal thin film is usually 50 to 50,000,
Preferably 50 to 10,000 people.

〔Example〕

Examples are shown below, but these reference examples and examples are for illustrating 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.

The evaluation of each characteristic in the examples was carried out by the following method.

Logarithmic viscosity ηinh is 98% sulfuric acid 100mf with polymer 0
．． 5g was dissolved and measured at 30'C in a conventional manner.

The strength and elongation and Young's modulus were measured using a constant speed extension type strength and elongation measuring machine.
Cut into 11 rectangles, initial grip length 30mm,
A load-elongation curve was drawn five times at a tensile speed of 30 M/min, and the calculation was made from this.

The expansion coefficient was measured using a thermomechanical analyzer, with a width of 5III.
fl+, 0.05 kg/for a sample with a length between grips of 15 mm.
A load of mm2 was applied. For thermal expansion coefficient, 2
The dimensional change of the sample was measured between 5 and 250°C.
It was calculated by dividing the rate of change between 50°C by 225. On the other hand, in the case of the hygroscopic expansion coefficient, the relative humidity was first maintained at 20% at 25°C, then humidified using a humidifier until the relative humidity rose to 80%, and the dimensional change rate during this period was calculated by dividing by 60. .

The moisture absorption rate was calculated from the weight measured after the film was left standing at 25°C and 150% relative humidity for 48 hours, and the weight of the film obtained by drying it in a vacuum dryer at 120°C until a constant weight was reached.

Thermal shrinkage rate at 250℃ is 0.05 kg/mm2
It was calculated from the dimensional changes at room temperature (25"c) before and after the open treatment, after being left in an oven at 250°C for 30 minutes under a tension of .

Examples 1 to 5 and Comparative Examples 1 to 4 A PPTA polymer with ηinh of 5.5 was dissolved in 97.7% sulfuric acid at a polymer concentration of 12.5% 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 11,500 poise. In order to facilitate film formation, the 20 dope was degassed under vacuum while being maintained at about 70°C. This case also had optical anisotropy as described above, and the viscosity was 4800 poise. A 1.5m curved pipe from the tank to the die through the filter and gear pump is kept at about 70℃, and cast from a gouie with a slit of 0.1ma+X300 value to a tantalum belt polished to a mirror surface. The cast dope was made optically isotropic by blowing air at about 105° C. with a humidity of 12%, and the dope was introduced together with the belt into water at 5° C. to solidify.

The coagulated film is then peeled off from the belt and heated to approximately 30°C.
It was washed by running it in hot water, then in a 0.5% NaOH aqueous solution, and then in room temperature water. The washed film was stretched by 15% in each of the length and width directions using a tenter without being dried, and then dried with hot air at 370° C. under a fixed length using another tenter. Furthermore, the film is guided into the third tenter, and the gripping length in the width direction and length direction is 5%.
Adjust the clip-shaped gripping part so that it becomes smaller
Heat treatment (heat fixation) was performed at the temperature shown in the table. The tension in the third tenter was in the range of 0-0.3 kg/mm''.

The obtained film had a thickness of 14'pm, η1nh5,0
~5.2, and the density was between 1.390 and 1.405 g/aj. Other properties are shown in Table 1.

The films obtained in Examples 1 and 3 were loaded into a vacuum chamber and subjected to glow treatment under an Ar atmosphere of a 10-inch I-hole.
Next, the vacuum chamber was evacuated to 1000 mt, and the Co-Ni alloy was deposited to a thickness of 1200 nm by electron beam evaporation while the film was run along a drum heated to 100°C. , a metallized film of the present invention was obtained.

This was slit to make a magnetic tape, and evaluated using the following method, and the results are shown in Table 2.

Running performance i Using a VH3 video tape recorder,
We observed the screen fluctuation due to tape running.

The atmosphere was 25° C. and 165% RH.

Note: In the table, the values excluding moisture absorption rate indicate the average value in the length direction and width direction, and the difference in physical property values depending on the direction was within 8%.

○: Running performance is smooth and there is no fluctuation in the playback screen.

×: Running performance deteriorates and fluctuations occur in the playback screen.

Durability: After repeated running 100 times, scratches on the magnetic surface, wrinkles and folds in the missing tape were observed. The atmosphere was 25°C, 155%R, and below 1.

◎: No scratches, chips, wrinkles, or breaks at all.

O: Very weak scratches and wrinkles are observed.

×: Severe scratches, missing wrinkles, and folds in the magnetic layer are observed.

Dropout: Video recording was performed, and the amount of attenuation of the video output during playback was 18 dB, and the dropout was measured with a dropout counter for 10 minutes with a ti1 continuous open time of 20 seconds or more, and a relative comparison was made.

Heat resistance = 85° C., 130% RH for 24 hours, and the appearance of curls etc. was observed.

Next, using the same electron beam evaporator, approximately 1800
A human-thick ferromagnetic layer of cobalt and cobalt oxide was formed on the PPTA films of Examples 2 and 4 to form the metallized films of the present invention.

This was also slit to make a magnetic tape, and the results of evaluation using the method described above are shown in Table 2.

In addition, in the PPTA films of Comparative Example 1 and Comparative Example 2,
The same vapor deposition as in Example 1 was performed, and the tape was slit to obtain a magnetic tape. The properties of these tapes are shown in Table 2. The reason for the poor heat resistance is thought to be that the hygroscopic expansion coefficient is large (Comparative Example 2) and the thermal expansion coefficient is negative (Comparative Example 1), which are significantly different from these of the vapor-deposited metal layer, so it tends to curl easily. Ta.

Next, a magnetic tape was produced in the same manner as in Example 1 using a commercially available polyimide film of 12.5 μm.

The evaluation results of this base film as a magnetic tape are shown in Table 2 (Comparative Example 3).

Furthermore, vapor deposition was attempted using a polyethylene terephthalate film in the same manner as in Example 1, but the film was deformed and holes were formed, making it impossible to obtain a vapor-deposited film (Comparative Example 4).

Margins below Next, a mixture of indium oxide and tin oxide in an amount of 7.5% by weight was vacuum-deposited onto the film of Example 5 shown in Table 1.

The resulting film is a low oxide of indium metal;
Film thickness: 350, surface resistance: 6Ω/a+1.600 nm
The conductive film had a light transmittance of about 38%.

Even when this vapor-deposited film was heated at 300° C. for 30 minutes and at 200° C. for 2 hours, no change in performance or occurrence of curling was observed.

Example 6 CoNi alloy was laminated to a thickness of 2,500 mm by sputtering on the film of Example 5 shown in Table 1, and this was slit to form a magnetic tape. As a result of evaluation using the method described above, all Good tape properties were obtained for the following items.

Example 7 In Example 4 of Table 1, when producing PPTA film,
A PPTA film with a thickness of 465 μm was obtained by adjusting the ratio between the dope discharge speed from the die and the belt movement speed. This film matched the film of Example 4 in Table 1 within measurement error in all other properties except for thickness.

In this example, an example of manufacturing a metallized film for a perpendicular magnetic recording medium from a PPTA film obtained in this manner will be described.

The inside of the vacuum chamber of the semi-continuous electron beam evaporation apparatus is evacuated by the exhaust system until the pressure becomes below 1X10-5 Torr. Next, a mixed gas of 20% by volume of oxygen and the balance of nitrogen was introduced as the introduced gas through the barrier pull leak valve until the pressure in the vacuum chamber reached 2 x 10-' Torr. It was run at a speed of about 2 m/min, and a ferromagnetic layer made of iron and iron compounds with a thickness of about 2,000 layers was continuously formed by electron beam evaporation. The vacuum chamber of the device is equipped with a film running system consisting of an unwinding roll, a cooling drum, and a take-up roll, and is equipped with an electron beam evaporator with a recess directly below the cooling drum to control the flow of evaporated vapor. A shielding plate having an opening such that the angle of incidence on the cooling drum was 16 degrees or less was placed close to the cooling drum.

The obtained magnetic recording medium (metallized film) had a perpendicular coercive force of 9700 e and a perpendicular anisotropy magnetic field of 3.9 K O
These properties hardly changed even after being left open for 8 hours at 160°C.

Furthermore, it was confirmed that the magnetic anisotropy coefficient of the magnetic recording medium before being placed in the oven was 2.1, that is, it was larger than 1.0 and had an axis of easy magnetization in the direction perpendicular to the substrate surface.

In addition, as a result of compositional analysis of the ferromagnetic layer, the main components of the ferromagnetic layer are Fe, Fezo3, Fe204, Fe (OH)
It turns out that it is composed of z.

Next, using the same semi-continuous electron beam evaporation apparatus, the above-mentioned running system was installed, which had a shielding plate inside which had an opening so that the incident angle of the evaporated vapor flow to the cooling drum was 16 degrees or less. With the PPTA film placed and cobalt placed in the recess of the electron beam evaporator, the vacuum chamber of the vacuum evaporator is evacuated to below 1XIO"5 Torr by the exhaust system, and then the oxygen gas is removed using the barrier pull leak valve. The PPTA film was heated at about 3 m/m in an atmosphere introduced through the vacuum chamber until the pressure in the vacuum chamber reached 3 x 10-'Torr.
A ferromagnetic layer of cobalt and cobalt oxide with a thickness of about 1800 nm was formed on the PPTA film by electron beam evaporation while running at a speed of in. Its perpendicular coercive force is 10400e, and its perpendicular anisotropy field is 4.
5KOe, the magnetic anisotropy coefficient was 1.8, and it was a perpendicular magnetic recording medium (metalized film) having an axis of easy magnetization perpendicular to the substrate surface.

Further, the analysis revealed that the ferromagnetic layer mainly contains Co and Coo.

Example 8 99 containing SiO2 PPTA with ηinh of 4.8
A dope containing about 0.05% by weight of dispersed 5in2 having optical anisotropy of 3600 poise and having optical anisotropy at 45°C was obtained by dissolving 12% in 5% sulfuric acid. After degassing and filtering, 0.08mm
The dope was cast onto a tantalum belt through a die with a slit of X300 value. The cast dope was converted to a clear optically isotropic dope by blowing air at about 75° C. with a relative humidity of about 80%, and then coagulated with a 10% aqueous sulfuric acid solution at 0°C. After peeling off the coagulated film from the belt, add room temperature water, 2% caustic soda aqueous solution, approx.
Washed sequentially with water at ℃.

The washed wet film containing approximately 250-350% water was stretched 1.2 times in MD and 1.25 times in TD using a tenter, and then dried at a constant length in a tenter with circulating hot air at 180°C. A 400° C. hot plate was installed at the exit of the drying tenter to heat the running film from above and below. Next, the film was introduced into a heat treatment tenter whose temperature was controlled at 300 to 310° C., and the film was run and heat-set while being shrunk by 3% in MD and TD.

The obtained film had a thickness of 2.0 am, η1nh4
．． 4. Density 1.401 g/ci, strength 27 kg/
mm", elongation 17%, Young's modulus 1120 kg/mm"
, moisture absorption rate 0.9%, thermal contraction rate 0.01% or less, thermal expansion coefficient 14 x 10-"m/nm/"C1 hygroscopic expansion coefficient 1
The film had isotropic properties of 1×IO−′ mm/mm/%RH.

The obtained PPTA film was placed in an electron beam vacuum evaporation apparatus, and aluminum was evaporated in such a manner that the film resistance was 41/port to obtain a metallized film. This vapor-deposited film was slit (width: 6 mm), passed through an element winder to produce a capacitor element, and further end-face sealed and lead wires were attached by conventional methods to produce a capacitor.

For comparison, a metallized film capacitor was also made from a 2 μm thick polyethylene terephthalate (PET) film, and the superiority of the metallized film of the present invention became clear in the process.

That is, the PPTA film used in this example had much greater strength and Young's modulus than the PET film, so it was stiff despite being as thin as 2 μm, and was easy to deposit. This ease of deposition was further enhanced by the ability of PPTA films to be subjected to high tensions in conjunction with their high strength and Young's modulus characteristics even at elevated temperatures. Furthermore, since the PPTA film used in this example had a thermal expansion coefficient close to that of aluminum and a small hygroscopic expansion coefficient, the metallized film did not curl. Furthermore, due to the low thermal shrinkage, no changes occurred even when the capacitor was immersed in a solder bath.

〔Effect of the invention〕

The metallized film of the present invention has no difference in dimensional stability with respect to temperature and humidity between the metal thin film layer and the base film, so it can be placed in a high temperature solder bath (250°C or higher) or in a flow soldering atmosphere (240°C or higher). Even if there is a high temperature atmosphere,
For example, even when placed in a closed car in the summer, the performance changes are much smaller than in conventional metallized films. Furthermore, since the moisture absorption rate is low, the adhesion between the metal thin film and the film is high based on the chemical affinity of the polymer made essentially of PPTA. In addition, the unique properties of the base PPTA film, such as high strength,
High Young's modulus, excellent electrical insulation, heat resistance, oil resistance, pressure resistance, chemical resistance other than strong acids, and structural compactness are maintained in the metallized film. Because of these characteristics, the metallized film of the present invention is useful as a magnetic recording medium, a transparent conductive film, a capacitor, a heat-resistant gas barrier film, a flexible printed circuit board, a carrier tape, and the like.

Claims (1)

[Claims] (1) A film made of para-oriented aromatic polyamide with a logarithmic viscosity of 3.5 or more, and a coefficient of thermal expansion from 25°C to 250°C of (0 to 15) × 10^-^6 mm/m
m/℃, heat shrinkage rate at 250℃ is 0.1% or less, 2
Hygroscopic expansion coefficient at 5℃ is 30 x 10^-^6mm/
mm/%RH or less, Young's modulus in all directions is 700k
A metallized film comprising a metal thin film provided on at least one surface of the film, the moisture absorption rate being 2.5% by weight or less at 25° C. and 50% RH.