JP2863984B2 - High rigidity long film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-rigidity long film, and more particularly, to a high-rigidity long film excellent in quality and workability because of special requirements as a film. It is about.

[0002]

2. Description of the Related Art Aromatic polyamide films and polyimide films are disclosed in JP-A-49-131247, JP-A-51-81854, JP-A-51-81880, JP-A-52-82953, JP-A-52-84
No. 245, JP-A-52-85251, JP-A-58-42649, JP-A-59-45124, JP-A-61-246918, JP-A-62-7
No. 0421, JP-A-60-15436, JP-A-60-15437 and JP-A-62-48726.

[0003] However, some of the films disclosed therein disclose the surface shape,
Despite the critical importance of film processability,
There is almost no known material referring to processability. Particularly, in the case of a so-called high-rigidity film with a high Young's modulus, the rigidity makes it difficult to perform processing such as film slitting, coating, laminating, etc. Troubles like lowering it are not endless.

On the other hand, regarding the problem of curling of a film, Japanese Patent Application Laid-Open No. 51-81854 discloses a method of suppressing curling of a highly rigid film by reducing the ion content in the film. However, this method alone has not completely solved the problem of improving the processability of a highly rigid film.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-rigidity long film which has good surface quality, has little decrease in surface quality during processing, and has excellent workability.

[0006]

That is, the present invention relates to an aromatic polyamide or polyimide film having a Young's modulus (Mi) of 700 to 2500 kg / mm ² , wherein the film has a Young's modulus (Mi) and a lengthwise direction. Dimensional difference rate dL (%)
Satisfies the following general formula (1), and the ratio of the thickness variation to the average thickness of the film is 0 to 5%.

0 ≦ dL · Mi ≦ 100% · kg / mm ² (1) The aromatic polyamide used in the present invention is substantially constituted by a unit selected from the group consisting of the following structural units. —NH—Ar ₁ —NH— (1) —CO—Ar ₂ —CO— (2) —NH—Ar ₃ —CO— (3) where Ar ₁ , Ar ₂ and Ar ₃ are at least one aromatic ring And may be the same or different. Representative examples of these include the following chemical formula 1.

[0008]

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Here, X represents —O—, —CH ₂ —, —SO ₂
-, -S-, -CO- and the like. Further, the aromatic polyamide in the present invention also includes those in which a part of hydrogen on the ring of these aromatic rings is substituted with a halogen group, a nitro group, an alkyl group, an alkoxy group, or the like. Among the above aromatic polyamides, those in which 80 mol% or more of all the aromatic rings are bonded at the para position are particularly preferable.

The polyimide used in the present invention includes:
The polymer contains one or more aromatic rings and one or more imide groups in the repeating unit of the polymer, and is represented by the following general formula (2) or (3).

[0011]

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[0012]

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Here, Ar ₄ and Ar ₆ contain at least one aromatic ring, and two carbonyl groups forming an imide ring are bonded to adjacent carbon atoms on the aromatic ring. This A
r ₄ is derived from an aromatic tetracarboxylic acid or an anhydride thereof.

[0014]

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Where Y is -O-, -CO-, -CH
_{2 -, - S -, -} SO 2 - and the like. In addition, the above chemical formula 3
In the formula, Ar ₆ is derived from tricarboxylic anhydride or its halide. Ar ₅ and Ar ₇ in Chemical formulas 2 and 3 contain at least one aromatic ring and are derived from aromatic diamines and aromatic isocyanates. Representative examples of Ar ₅ or Ar ₇ include the following chemical formula 5.

[0016]

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Here, Z represents —O—, —CH ₂ —, —S
_{-, - SO 2 -, -} CO- , and the like. In addition, part of the hydrogen on the ring of these aromatic rings is a halogen group, a nitro group,
Also included are those substituted with an alkyl group, an alkoxy group, or the like. Among the above polyimides, polyimides in which at least 80% of Ar ₅ and Ar ₇ are aromatic rings bonded to the para position are particularly preferred.

The aromatic polyamide film or the polyimide film of the present invention may contain a lubricant, an antioxidant, other additives, etc. as long as the physical properties of the film are not impaired or the object of the present invention is not adversely affected. A polymer may be included. The Young's modulus (Mi) of the film of the present invention is 70
0-2500 kg / mm ² , preferably 9
It is 00 to 2500 kg / mm ² . Young's modulus is 700
This is because a film having a weight of less than kg / mm ² is no longer a film in the category of a highly rigid film, and there is no need to apply the technical requirements of the present invention. On the other hand, 25
This is because a film exceeding 00 kg / mm ² is easily broken and brittle, and the usefulness as a film is reduced.

The high Young's modulus film of the present invention can be realized by increasing the number of para-oriented components in the molecular structure and by applying a relatively high stretching ratio at the time of production to highly orient the molecular chains. In the present invention, it is important that the dimensional difference dL in the film length direction is in a special range as a combination value with the Young's modulus Mi of the film. The dimensional difference rate dL is qualitatively the so-called “slack” of the film.
When the maximum length is L ₁ and the minimum length is L ₂ , it is defined as dL = 100 × (L ₁ −L ₂ ) / L ₂ (%). As a measuring method, for example, after spreading the film with a constant tension, 1 to 1 so that both ends are parallel in the width direction.
There is a method of cutting into a fixed length of about 3 m, and then measuring the length L in the length direction at each position in the width direction. The invention generally has a width of about 300 mm or more and a length of 50-100.
000 m film would be applied.

In the present invention, the product of the Young's modulus and the dimensional difference in the length direction needs to be in the range of 0 to 100% · kg / mm ² . That is, if this value exceeds 100, the flatness of the film deteriorates and the Young's modulus is large, so that it is no longer possible to perform the processing smoothly only by adjusting the tension in the processing step. For example, the release property of the film wound into a roll becomes poor, the accuracy and yield of the film slit is reduced, the coating on the film is disturbed, and the lamination of other materials on the film cannot be uniformly performed. The surface of the film is damaged when the film is processed, and the rolled-up shape of the film after the processing is deteriorated. Preferably, this value is 80
% · Kg / mm ² or less. The present invention can be applied not only to the so-called balance type in which the physical properties are constant in all directions in the film plane, but also to the tensile type in which the length direction or the width direction is reinforced, and in the latter case, The Young's modulus adopts a value in the length direction and estimates the product of the product of the dimensional difference rate in the length direction.

Such characteristics of the film of the present invention can be realized by a special production method as described in detail later. That is, in the production of a high Young's modulus film, a step of causing about 5% or more of dimensional change (shrinkage or stretching) of the film or a step of restricting shrinkage of the film under conditions that cause about 5% or more shrinkage when placed in a free state. In regard to the above, it is necessary to control the distribution of the tension acting on the film and the temperature distribution within a specific range. Further, regarding the storage of the film after the production, it is necessary to prevent the application of external force, temperature and humidity in the width direction of the film from becoming uneven.

The present invention has an average thickness of about 1 to 1000 μm.
However, it is important that the ratio of the thickness variation to the average thickness is 0 to 5%. Preferably, this ratio is 0-4%. If the ratio exceeds 5%, the rolled-up film becomes poor in roll form, and the release itself from the roll and the workability of the film after the release become poor.

The film of the present invention preferably has a thickness of 30 to 8
It has a strength of 0 kg / mm ² . This is considerably higher strength than a general film, and is one of the features related to the high rigidity film. The film of the present invention preferably has an elongation of 15 to 100%. This is because films with an elongation of less than 15% are almost completely brittle. On the other hand, it is generally desirable that the elongation is large,
In the case of a highly rigid film, the upper limit is actually about 100%. The elongation is the degree of polymerization and the degree of orientation of the polymer,
This can be achieved by adjusting the crystallinity and the like.

Further, the film of the present invention preferably has a coefficient of hygroscopic expansion in the film surface direction of 0 to 40 PPM /% RH, more preferably 0 to 25 PPM /% RH. If the coefficient of hygroscopic expansion in the direction of the film surface is too large, the dimensional change with respect to the change in humidity increases, which is not preferable because the handling of the film, the processability, and the performance in each application change.

The coefficient of hygroscopic expansion in the thickness direction of the film is preferably 0 to 600 PPM /% RH. More preferably, it is 0 to 500 PPM /% RH. If the coefficient of hygroscopic expansion in the film thickness direction is too large,
When the film is wound into a roll, the appearance of the film may deteriorate, resulting in deterioration of the flatness of the film and deterioration of workability. The reduction of the coefficient of hygroscopic expansion can be achieved by selecting the type of polymer, adjusting the degree of stretching orientation, the degree of crystallinity, and the polymer end group.

The film of the present invention preferably has a heat shrinkage at 200 ° C. of 0 to 0.5%. The reason is that if the heat shrinkage is large, the flatness of the film may be reduced when the film is subjected to a high-temperature history in the film processing step or the like. The reduction of the heat shrinkage rate depends on the choice of polymer type,
This can be achieved by heat setting or the like. The film of the present invention preferably has a dynamic friction coefficient with a metal mirror surface of 0.02 to 0.02.
0.25, more preferably 0.02 to 0.2.
Fifteen. If the coefficient of friction is too small, handling in the machining process becomes unstable, and if it is too large, wrinkles in the machining process
This is because the occurrence of distortion and damage are increased. Adjustment of the coefficient of friction can be achieved by selecting the amount, type, particle size, degree of dispersion, etc. of the lubricant.

The film of the present invention further comprises IEC-11
2 has a tracking resistance (CTI) of preferably 200 to 1,000. This indicates that the electrical insulation is excellent even in an ionic environment. The film of the present invention is preferably 0.8 μm.
The surface does not substantially contain coarse protrusions having a height of not less than m.
This characteristic of the film can be achieved by selecting the particle size and dispersity of the lubricant.

As the method for producing the film of the present invention, a production method suitable for each polymer is employed. As described above, the step of increasing the Young's modulus, the step of causing a dimensional change of the film, or the step of restricting shrinkage is performed. Need to be manufactured with special duty of care. First, with respect to the aromatic polyamide resin, if it is soluble in an organic solvent, it is polymerized directly in a solvent, or once a polymer is isolated and redissolved to form a solution, and then produced by a dry method or a wet method. Filmed. In addition, polyparaphenylene terephthalamide (PP
Those that are hardly soluble in organic solvents such as TA) are dissolved in concentrated sulfuric acid or the like to form a solution, and then formed into a film by a dry method or a wet method.

On the other hand, as for the polyimide resin, a tetracarboxylic anhydride is reacted with an aromatic diamine in an organic solvent to obtain a polyamic acid. The solution is obtained by dissolving, and they are formed into a film by a dry method or a wet method. In the dry method, the solution is extruded from a die, cast on a support such as a metal drum or an endless belt, and the drying or imidization reaction proceeds until the cast solution forms a self-supporting film.

In the wet method, the solution is extruded directly from a die into a coagulating liquid, or cast on a metal drum or an endless belt in the same manner as in the dry method, and, if necessary, after partial removal of the solvent, It is guided into the coagulation liquid and coagulated. Next, these films are washed with solvents and inorganic salts in the films and subjected to processes such as stretching, drying and heat treatment.

As described above, in any of the film forming methods, the area stretching ratio needs to be 0.9 to 5.0 times, and preferably 1.0 to 4.0 times. If the area stretching ratio is less than 0.9, the Young's modulus becomes insufficient, and if it exceeds 5.0 times, it becomes difficult to keep the dimensional difference ratio within the range of the present invention. Also, in any of the film forming methods, in order to keep the dimensional difference ratio within the range of the present invention, a step of causing a dimensional change (shrinkage or stretching) of the film by about 5% or more or a free state is about 5%. %, Regarding the step of restricting shrinkage under conditions that cause shrinkage of at least%, adjust the pattern and speed of stretching and shrinkage,
The distribution (variation) of the tension vector acting on the film needs to be within about ± 10% in both the direction (angle) and the strength, and the temperature distribution also needs to be within about 10 ° C., preferably within about 5 ° C. It turns out that it is necessary to perform while managing.

Further, the storage of the film after film formation is usually carried out.
It is performed in the form of a roll wound up on a cylindrical bobbin, but it is necessary to take care that the external force is not applied unevenly in the width direction, and that heating, moisture absorption, drying, etc. do not become uneven in the width direction. is there. In order to improve the slipperiness of the films and prevent the blocking phenomenon, a method of mixing fine particles in the film is usually adopted, and the fine particles are also referred to as a lubricant. Examples of the fine particles include an organic compound and an inorganic compound, and usually, for example, SiO ₂ , TiO ₂ , ZnO, Al ₂
Inorganic compounds such as O ₃ , CaSO ₄ , BaSO ₄ , CaCO ₃ , carbon black, zeolite, and other metal powders are used. The particle diameter is often selected from 0.01 to 2 μm, and the addition amount is often selected from 0.03 to 5% by weight. That is,
The fine particles are mixed in a solution of an aromatic polyamide resin or a polyimide or a polyamic acid as a precursor of a polyimide, and the solution is formed into a film. At this time, in order to improve the dispersion of the fine particles, a homogenizer of an ultrasonic system or a stirring system is preferably used.

The film may contain a colorant such as a dye or a pigment, a flame retardant, an antistatic agent, an antioxidant, and other modifiers, as long as they do not contradict the object of the present invention. Good.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments. In addition, the measuring method of the characteristic of the film under execution is as follows. (Method of measuring characteristics) The method of measuring characteristic values according to the present invention is as follows. (1) Method of measuring film thickness, strength, elongation and Young's modulus The film thickness is measured with a dial gauge having a measurement surface of 2 mm in diameter. The strength, elongation, and Young's modulus were measured at a measurement length of 100 mm and a pulling speed of 50 mm / min using a constant-speed elongation type elongation measuring machine. (2) Method of measuring heat shrinkage A sample piece of 2 cm × 5 cm is cut out from a film and 4c
The mark is made by making a mark with a knife at intervals of m.
After leaving for 72 hours in an atmosphere of 5% RH, the distance between the labels was read and measured with a microscope, and then left in a hot air oven at 200 ° C. for 2 hours without restraining, then again at 23 ° C. and 55% RH. After leaving for 72 hours in the atmosphere of
The distance between the labels was read and measured with a microscope. (3) Method of measuring dimensional difference (dL) The film was spread with a tension of about 10 to 20 g / mm ² ,
A pair of parallel lines are drawn in the width direction of the film at an interval of m. Next, the film is cut substantially parallel to the length direction of the film at intervals of about 1 cm to form a strip having a size of about 1 mx 1 cm. Then, by measuring the length of these strips precisely, the maximum seek length L ₁ and a minimum length L _2, calculated in dL = 100 × (L1-L2 ) / L2 (%). (4) Method for measuring coefficient of hygroscopic expansion in the film surface direction Thermodynamic property measuring instrument (TMA, TM7 manufactured by Vacuum Riko Co., Ltd.)
000 type), a sample with a width of 5 mm was attached, and
After removing the residual strain of the sample by raising the temperature once to 300 ° C. under 3 g, the sample was cooled under a dry nitrogen stream, and the change in humidity between dry nitrogen and air and the change in the dimensions of the film were measured at 23 ° C. Then, it was calculated. (5) Method of measuring dynamic friction coefficient A 50 g load is applied to one end of a 1 cm wide film on a stainless steel fixed roll (60 mm in diameter) polished to a mirror surface as a metal mirror surface so as to have an angle of 90 °. ,
The other end was pulled at a speed of 20 cm / min, and calculated from the tensile tension of the film at this time using Euler's equation. (6) Measurement method of tracking resistance (CTI value) An NH ₄ Cl aqueous solution was dropped on a film according to IEC-112, and the maximum applied voltage at which the number of drops indicating tracking destruction was 50 or more was defined as the CTI value. . (7) Method of Measuring Coarse Protrusion on Surface Using a scanning electron microscope manufactured by JEOL Ltd., at least 10 photographs of different parts taken at a magnification of 1000 were used.
The number of protrusions having a height of 8 μm or more was examined.

[0035]

Example 1 Polyparaphenylene terephthalamide (P
PTA) in 99.8% concentrated sulfuric acid and a polymer concentration of 12
%, And cast on an endless belt from a die having a slit interval of about 300 μm. In the concentrated sulfuric acid, silica particles of 0.04 μm were previously dispersed by an ultrasonic stirrer so as to be 0.3% by weight with respect to PPTA. After heating and doping on a belt, the dope is converted from a liquid crystal phase to an isotropic phase, solidified in 45% sulfuric acid at 0 ° C., neutralized, washed with water, and cut in a length direction of 1.05.
After stretched twice, stretched transversely to 1.05 times with a clip tenter and then dried with hot air at 150 ° C while maintaining a fixed length, then heat-stretched at 400 ° C, free-heated at 300 ° C, and rolled up, polyethylene In a plastic bag. Here, in order to prevent temperature unevenness of 5 ° C. or more from occurring in the width direction of the film during the transverse stretching and drying, cooling and heating of the tenter clip are sufficiently performed by using a specially added device. In order to prevent a difference of 5 ° C. or more between the center part and the end part, heat retention was added to prevent heat radiation at the end part.

P obtained in a width of 500 mm and a length of 300 m
The PTA film had an average thickness of 50 μm, and there was almost no difference in physical properties in the longitudinal direction and the width direction, as shown in Table 1. Remove the film from the polyethylene bag with a width of 1.
A slitting machine was used to slit to 00 mm. The slit is made without any problem, and the end surface is uniform and uniform.
Five films of 00 mm width were obtained. The film after the slit could be released smoothly without any damage.

[0037]

[Comparative Example 1] In Example 1, when the special addition device for the tenter clip and the tension heat treatment heater was removed and the normal operation was resumed, the film was subjected to transverse stretching, drying, and tension heat treatment at a maximum of 6, 11, 12 ° C in the width direction of the film. It was found that there was temperature variation. In this state, the other is the first embodiment.
The film was wound up exactly as described above. Table 1 shows the physical properties of the film.

A slit was made in the same manner as in Example 1, except that
Because the tension cannot be applied uniformly to the 00 mm width film, the slit surface is uneven and the end face has irregularities,
Also, so-called "ear height" occurred at the end. When the film after slitting was released, it was difficult to release the film because the "ear height" portion was stuck and it was inevitable that the film was torn or wrinkled, and the surface of the film was scratched.

[0039]

Example 2 and Comparative Example 2 Example 1 was the same as Example 1 except that the stretching ratio was changed to 1.20 in both the length and width directions. Here, after the transverse stretching was performed 1.22 times in the transverse stretching section of the clip tenter, the overall stretching rate was 1.20 in the drying section.
Example 2 adjusted slightly so as to be doubled to relax
Comparative Example 2 was obtained in which the clip tenter was stretched 1.15 times in the horizontal stretching portion and further stretched in the drying portion so as to be 1.20 times as a whole.

According to an experiment confirmed separately, it was found that the film after washing was shrunk by about 20 to 30% in the drying step. It was presumed that tension imbalance was likely to occur. The physical properties of the obtained film were balanced in length and width, and as shown in Table 1. 500mm
An epoxy resin was coated on a film having a width of 300 m and a length of 300 m. As a result, the film of Example 2 was approximately 20 μm.
m, but the film of Comparative Example 2 could not avoid coating unevenness.

[0041]

Example 3 and Comparative Example 3 Polyparaphenylene-2-chloroterephthalamide (PPClTA) was dissolved to a polymer concentration of 13% by weight, and cast from a die having a slit interval of about 100 μm on an endless belt. In the concentrated sulfuric acid, 0.02 μm titanium oxide fine particles were previously dispersed by an ultrasonic disperser so as to be 0.2% by weight with respect to PPClTA. The same operation as in Example 2 was performed to prepare a film. However, after applying 1.18 times stretching in the transverse stretching portion of the clip tenter, the film was slightly relaxed in the drying portion to give a stretching ratio of 1.15 times as a whole as Example 3. On the other hand, the film was stretched 1.15 times in the transverse stretching section, and the drying was performed under a constant length.

A film having balanced properties in the vertical and horizontal directions was obtained, and is shown in Table 2. Also, 500mm width, 300m
Using an epoxy-based adhesive, these films with a length
It was bonded to a copper foil having a thickness of 35 μm. Although the copper-clad board of the film of Example 3 was obtained without any problems, the copper-clad board of the film of Comparative Example 3 was wrinkled in some places of the film despite various changes in the film tension during lamination. Only a board could be obtained.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

According to the present invention, a high-rigidity long film with good flatness can be obtained, the surface quality is good before and after the film is processed, and the roll shape is good, so that the film can be released from the roll state. Excellent surface treatment, slitting,
Processing such as coating and laminating is easy.
That is, the film is easy to handle at the time of processing, the deterioration of the film quality at the time of processing (for example, scratching) is small, and high-yield processing is possible. That is, conventionally, high-rigidity films have been neglected in terms of workability, but the present invention provides a high-rigidity long film excellent in workability.

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI C08L 77:00 79:08

Claims (3)

(57) [Claims] 1. A Young's modulus (Mi) of 700 to 2500 k
g / mm ^{2 of} an aromatic polyamide or polyimide film having a Young's modulus (Mi) and a dimensional difference dL (%) in the length direction satisfying the following general formula (1):
And the ratio of the thickness variation to the average thickness of the film is 0
High rigidity long film of up to 5%. 0 ≦ dL · Mi ≦ 100% · kg / mm ² (1) 2. Thickness variation with respect to the average thickness of the film
2. The method according to claim 1, wherein the ratio is 0 to 4%.
High rigidity long film. 3. The film's Young's modulus (Mi) and length direction
And the dimensional difference dL (%) satisfy the following general formula (2).
The high-rigidity long film according to claim 1, wherein: 0 ≦ dL · Mi ≦ 80% · kg / mm ²  (2)