JPH07314554A - Highly rigid long film - Google Patents

Abstract

PURPOSE:To obtain a highly rigid long film excellent in the surface quality and machinability. CONSTITUTION:The high rigidity film is an aromatic polyamide or polyimide film having Young's modulus (Mi) in the range of 700-2500kg/mm<2>, wherein the Young's modulus(Mi) and the dimensional difference rate dL (%) in the longitudinal direction satisfy a general formula and the fluctuation of thickness with respect to the average thickness is in the range of 0-5%. 0<=3dL.Mi$100%.kg/mm<2>.

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 which is of good quality and excellent in processability because it has 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, and JP-A-52-82953. JP-A-52-84
No. 245, No. 52-85251, No. 58-42649, No. 59-45124, No. 61-246918, No. 62-7.
It is known from JP-A-0421, JP-A-60-15436, JP-A-60-15437, and JP-A-62-48726.

However, although some of the films disclosed therein disclose surface shapes,
Although film processability is extremely important,
There are almost no known documents that mention workability. Especially in the case of so-called high-rigidity film with high Young's modulus, because of its rigidity, it is difficult to process film slitting, coating, laminating, etc. There are constant problems such as lowering it.

On the other hand, regarding the problem of curling of the film, JP-A-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 the high-rigidity film.

[0005]

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

[0006]

That is, the present invention is an aromatic polyamide or polyimide film having a Young's modulus (Mi) of 700 to 2500 kg / mm ² , wherein the Young's modulus (Mi) of the film and the longitudinal direction are Dimensional difference rate dL (%)
Is a high-rigidity long film in which the following general formula (1) is satisfied and the thickness variation ratio 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 composed of 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, and typical examples of these include the following chemical formula 1.

[0008]

[Chemical 1]

Here, X is --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 atoms on the aromatic ring is substituted with a halogen group, a nitro group, an alkyl group, an alkoxy group or the like. Among the above aromatic polyamides, aromatic polyamides in which 80 mol% or more of all aromatic rings are bonded in the para position are particularly preferable.

As the polyimide used in the present invention,
The polymer has at least one aromatic ring and at least one imide group in the repeating unit of the polymer, and is represented by the following general formula (2) or (3).

[0011]

[Chemical 2]

[0012]

[Chemical 3]

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, and a typical example thereof is the following chemical formula 4.

[0014]

[Chemical 4]

Here, Y is --O--, --CO--, --CH.
_{2 -, - S -, -} SO 2 - and the like. In addition,
Among them, Ar ₆ is derived from tricarboxylic acid anhydride or its halide. Ar ₅ and Ar ₇ in the chemical formulas 2 and 3 include at least one aromatic ring and are derived from aromatic diamine and aromatic isocyanate. A typical example of Ar ₅ or Ar ₇ is the following chemical formula 5.

[0016]

[Chemical 5]

Here, Z is --O--, --CH _2- , --S.
_{-, - SO 2 -, -} CO- , and the like. Also, some of the hydrogens on the rings of these aromatic rings are halogen groups, nitro groups,
It also includes those substituted with an alkyl group or an alkoxy group. Among the above polyimides, a polyimide in which 80% or more of Ar ₅ and Ar ₇ are aromatic rings bonded to the para position is particularly preferable.

The aromatic polyamide film or the polyimide film of the present invention may contain other additives such as a lubricant, an antioxidant, other additives, etc., as long as the physical properties of the film are not impaired and the object of the present invention is not impaired. A polymer may be included. The Young's modulus (Mi) of the film of the present invention is 70.
It should be 0-2500 kg / mm ² , preferably 9
It is from 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 high-rigidity film, and it is no longer necessary to apply the technical requirements of the present invention. On the other hand, 25
This is because a film exceeding 00 kg / mm ² easily breaks and becomes brittle, and its usefulness as a film is reduced.

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

In the present invention, it is necessary that the product of the Young's modulus and the dimensional difference rate in the length direction is in the range of 0 to 100% · kg / mm ² . That is, when this value exceeds 100, the flatness of the film is deteriorated and the Young's modulus is large, so that it becomes difficult to perform the processing smoothly only by adjusting the tension in the processing step. For example, the releasability of the film wound into a roll is deteriorated, the precision and yield of the slit of the film are deteriorated, the coating on the film is disturbed, and the film cannot be uniformly laminated with other materials. That is, the film surface is scratched during the processing, and the appearance of winding the film after these processing into a roll is deteriorated. Preferably, this value is 80
% · Kg / mm ² or less. The present invention can be applied not only to a so-called balanced type whose physical properties are constant in all directions in the film plane, but also to a tensilized type reinforced in the length direction or the width direction. In the latter case, The Young's modulus is a product of the value in the length direction and the dimensional difference rate in the length direction.

Such characteristics of the film of the present invention can be realized by a special manufacturing method as described in detail later. That is, in the production of a high Young's modulus film, a step of causing a dimensional change (shrinkage or stretching) of the film by about 5% or more, or a step of limiting the shrinkage of the film under the condition of causing a shrinkage of about 5% or more when left in a free state. With respect to the above, it is necessary to control the distribution of tension acting on the film and the temperature distribution in a special range. Further, regarding storage of the film after manufacturing, it is necessary to prevent unevenness in external force, temperature and humidity, etc. in the width direction of the film.

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 wound shape of the film wound into a roll will be poor, and the release itself from the roll and the processability of the film after release will be poor.

The film of the present invention is preferably 30-8.
It has a strength of 0 kg / mm ² . This is a considerably higher strength than ordinary films, and is one of the characteristics associated with high rigidity films. Also, the film of the present invention preferably has an elongation of 15 to 100%. Films with an elongation of less than 15% tend to be brittle. On the other hand, it is generally desirable that the elongation is large,
In the case of a high-rigidity film, the upper limit is practically about 100%. Elongation is the degree of polymerization or stretch 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. When the coefficient of hygroscopic expansion in the film surface direction is too large, the dimensional change due to humidity change becomes large, resulting in unfavorable results such as handling of the film, processability, and changes in performance in various applications.

The coefficient of hygroscopic expansion in the film thickness direction is also 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 rolled into a roll, the winding appearance may be poor, resulting in poor flatness and processability of the film. The reduction of the coefficient of hygroscopic expansion can be achieved by selecting the polymer type, adjusting the degree of orientation of stretching, the degree of crystallinity, and the end groups of the polymer.

The film of the present invention preferably has a heat shrinkage ratio at 200 ° C. of 0 to 0.5%. This is because if the heat shrinkage is large, the flatness of the film may be deteriorated when it is subjected to a high temperature history in the film processing process or the like. To reduce the heat shrinkage, select the polymer type,
It can be achieved by heat setting. The film of the present invention preferably has a dynamic friction coefficient of 0.02 to the metal mirror surface.
0.25, and more preferably 0.02 to 0.
It is 15. If the friction coefficient is too small, handling becomes unstable in the machining process, and if it is too large, wrinkles in the machining process occur.
This is because distortion and scratches increase. The friction coefficient can be adjusted by selecting the amount, type, particle size, dispersity, etc. of the lubricant.

The film of the present invention further comprises IEC-11
The tracking resistance (CTI) measured according to 2 has preferably 200-1000. This indicates that the electric insulation is excellent even in an ionic environment. The film of the present invention preferably has a thickness of 0.8μ.
Substantially no coarse protrusions on the surface having a height of m or more are contained.
This feature of the film can be achieved by selecting the particle size and dispersity of the lubricant.

Regarding the method for producing the film of the present invention, a production method suitable for each polymer is adopted, but as described above, the Young's modulus is increased, the step of causing the dimensional change of the film or the shrinkage limiting step. Therefore, it is necessary to manufacture it under a special duty of care. First, as for the aromatic polyamide resin, if it is soluble in an organic solvent, it is polymerized directly in a solvent, or once the polymer is isolated and then redissolved to prepare a solution, which is then prepared by a dry method or a wet method. Be filmed. In addition, polyparaphenylene terephthalamide (PP
For those that are poorly soluble in organic solvents such as TA), they are dissolved in concentrated sulfuric acid or the like to give a solution, and then a film is formed by a dry method or a wet method.

On the other hand, regarding the polyimide resin, tetracarboxylic acid anhydride and aromatic diamine are reacted in an organic solvent to form a polyamic acid, and this solution is directly or once subjected to a ring-closing treatment to form a polyimide, which is then reused in a solvent. A solution is obtained by dissolving them, 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 and cast onto a support such as a metal drum or 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 is cast on a metal drum or an endless belt as in the dry method, and if necessary, after partially removing the solvent, It is introduced into the coagulation liquid and coagulated. Next, these films are washed with a solvent, an inorganic salt and the like in the film and subjected to treatments such as stretching, drying and heat treatment.

As described above, in any of the film forming methods, it is necessary to make the area stretching ratio 0.9 to 5.0 times, preferably 1.0 to 4.0 times. If the area draw ratio is less than 0.9, the Young's modulus becomes insufficient, and if it exceeds 5.0, it becomes difficult to bring the dimensional difference ratio within the range of the present invention. Further, in any of the film forming methods, in order to keep the dimensional difference rate within the range of the present invention, it is about 5 when the film is subjected to a step of causing a dimensional change (shrinkage or stretching) of about 5% or more or in a free state. In the process of limiting the shrinkage under the condition of shrinkage of more than 100%, adjusting the pattern and speed of stretching and shrinkage,
The distribution (variation) of the tension vector acting on the film must be within ± 10% in both direction (angle) and strength, and the temperature distribution should also be within 10 ° C, preferably within 5 ° C. I found it necessary to manage it.

Further, the storage of the film after the film formation is usually
It is performed in a roll wound on a cylindrical bobbin, but it is necessary to take care so that the external force does not become uneven in the width direction and heating, moisture absorption, drying, etc. do not become uneven in the width direction. is there. In order to improve the slipperiness between the films and to prevent the blocking phenomenon, a method in which fine particles are mixed in the film is usually adopted, and the fine particles are also referred to as a lubricant. The fine particles include organic compounds and inorganic compounds, but 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 size of these is often selected to be 0.01 to 2 μm, and the addition amount is selected to be 0.03 to 5% by weight. That is,
It is manufactured by mixing the above fine particles in a solution of aromatic polyamide resin or polyimide or a polyamic acid which is a precursor of polyimide, and forming a film of this solution. At this time, in order to improve the dispersion of the fine particles, an ultrasonic type or stirring type homogenizer is preferably used.

The film may contain coloring agents such as dyes and pigments, flame retardants, antistatic agents, antioxidants, and other modifiers, as long as they do not violate the object of the present invention. Good.

[0034]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, the measuring method of the characteristic of the film in process is as follows. (Characteristic Measuring Method) The characteristic value measuring method of the present invention is as follows. (1) Method for measuring film thickness, strength, elongation and Young's modulus The film thickness is measured with a dial gauge having a measuring surface with a diameter of 2 mm. The strength, elongation, and Young's modulus are measured with a constant-speed elongation type strong elongation measuring machine at a measurement length of 100 mm and a pulling speed of 50 mm / min. (2) Method of measuring heat shrinkage A sample piece of 2 cm × 5 cm was cut out from the film, 4c
Mark with scratches at m intervals with a knife and pre-set at 23 ° C, 5
After left in an atmosphere of 5% RH for 72 hours, the distance between the markers was read and measured with a microscope, and then left in a hot air oven at 200 ° C for 2 hours without being restrained, then again at 23 ° C and 55% RH. After leaving it in the atmosphere for 72 hours,
The distance between the markers was determined by reading with a microscope. (3) Measuring method of dimensional difference rate (dL) A film is spread with a tension of about 10 to 20 g / mm ^{2 to} about 1
A pair of parallel lines are drawn in the width direction of the film at intervals of m. Next, the film is cut substantially parallel to the length direction of the film at intervals of about 1 cm to make a strip of about 1 m × 1 cm. Then, the lengths of these strips were precisely measured to obtain the maximum length L ₁ and the minimum length L ₂ and calculated by dL = 100 × (L1−L2) / L2 (%). (4) Method for measuring coefficient of hygroscopic expansion in the film surface direction Thermodynamic characteristic measuring machine (TMA, manufactured by Vacuum Riko Co., Ltd. TM7
A sample with a width of 5 mm is attached to the (000 type), and the load is 0.
Under 3 g, the temperature was once raised to 300 ° C to remove the residual strain of the sample, then cooled in a dry nitrogen stream, and at 23 ° C, the humidity change between dry nitrogen and air and the dimensional change of the film were measured. And calculated. (5) Dynamic friction coefficient measurement method As a metal mirror surface, a stainless steel fixed roll (diameter 60 mm) polished to a mirror surface was applied with a load of 50 g on one end of a film with a width of 1 cm so as to form an included angle of 90 °. ,
The other end was pulled at a speed of 20 cm / min, and it was calculated from the tensile tension of the film at this time using the Euler equation. (6) Tracking resistance (CTI value) measurement method According to IEC-112, an aqueous NH ₄ Cl solution was dropped onto the film, and the maximum applied voltage at which the number of drops showing tracking breakdown was 50 or more was taken as the CTI value. . (7) Method for measuring coarse protrusions on the surface Using a scanning electron microscope manufactured by JEOL Ltd., at least 10 photographs of different parts were photographed at 1000 times.
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 with a polymer concentration of 12
%, And then cast on an endless belt from a die having a slit interval of about 300 μm. In concentrated sulfuric acid, silica particles of 0.04 μm were previously dispersed by an ultrasonic stirrer so that the content of silica particles was 0.3% by weight with respect to PPTA. After the moisture was absorbed on the belt at the same time as heating, the dope was converted from the liquid crystal phase to the isotropic phase, coagulated in 45% sulfuric acid at 0 ° C., neutralized, washed with water, and 1.05 in the length direction.
After being double stretched, it is transversely stretched 1.05 times by a clip tenter, then dried with hot air at 150 ° C while maintaining a constant length, then subjected to tension heat treatment at 400 ° C, free heat treatment at 300 ° C, and then rolled up, polyethylene. I put it in a plastic bag. Here, in order to prevent temperature unevenness of 5 ° C. or more in the width direction of the film during lateral stretching and drying, the device for cooling and heating the tenter clip is sufficiently used, and the temperature of the heater for the tension heat treatment is sufficient. In order to prevent a difference of 5 ° C. or more between the central part and the end part of the distribution, heat retention was added to prevent heat dissipation at the end part.

P obtained with 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, and the results are shown in Table 1. Width of the film taken out from the polyethylene bag is 1
A slitting machine was used to slit to 00 mm. Slitting is done without any problems, and the end faces are even.
Five 00 mm wide films were obtained. The film after slitting could be released smoothly and there were no scratches.

[0037]

[Comparative Example 1] In Example 1, when the tenter clip and the tension heat treatment heater special addition device were removed and returned to the normal state, a maximum of 6, 11, 12 ° C in the width direction of the film was obtained by transverse stretching, drying and tension heat treatment, respectively. It was found that there was a temperature variation of. In this state, the others are Example 1
The film was rolled up in exactly the same manner as. The physical properties of the film are shown in Table 1.

Slitting was performed in the same manner as in Example 1, but 5
Since the tension cannot be applied uniformly to the 00 mm width film, the slit points are not constant and the end surface has unevenness,
In addition, so-called "ear height" occurred at the end. When the film after slitting was released, it was difficult to remove it because the "ear height" part was stuck, and it was unavoidable that the film was torn or wrinkled, and that the surface of the film had scratches.

[0039]

Example 2 and Comparative Example 2 Same as Example 1 except that the stretching ratio was changed to 1.20 in both length and width. Here, the transverse stretching was performed 1.22 times in the transverse stretching portion of the clip tenter, and then the overall stretching ratio was 1.20 in the drying portion.
Example 2 was slightly adjusted so as to be doubled and adjusted.
Then, Comparative Example 2 was prepared in which the lateral stretching portion of the clip tenter was 1.15 times, and the drying portion was further stretched to obtain 1.20 times as a whole.

According to an experiment confirmed separately, it was found that the film after being washed with water shrinks by about 20 to 30% in the drying process, and when the film is stretched in the drying process, the stretching occurs in relation to the residual moisture, so that the film is localized. It was estimated that tension imbalance was likely to occur. The physical properties of the obtained film were balanced in the vertical and horizontal directions and were as shown in Table 1. 500 mm
A film having a width of 300 m and a length of 300 m was coated with an epoxy resin. As a result, the film of Example 2 was about 20 μm.
Although it was possible to uniformly coat the entire surface to a thickness of m, the coating of the film of Comparative Example 2 was inevitable.

[0041]

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

A film having well-balanced physical properties in length and width was obtained, and it is shown in Table 2. Also, 500 mm width, 300 m
These films with a length of
It was laminated with a copper foil having a thickness of 35 μm. The film of Example 3 gave a copper clad plate without any problems, but the film of Comparative Example 3 had various tensions of the film at the time of lamination, but the film had copper clad with wrinkles. I only got a board.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

According to the present invention, since a high-rigidity long film having good flatness can be obtained, the surface quality is good both before and after the film is processed, and because the wound shape is good, the film is released from the roll state. Excellent surface treatment, surface treatment, slitting,
Easy to process such as coating and laminating.
That is, the film is easy to handle during processing, there is little deterioration in film quality (for example, scratches) during processing, and high-yield processing is possible. That is, conventionally, the workability of the high-rigidity film was neglected, but the present invention provides a high-rigidity long film having excellent workability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area C08L 79:08

Claims (1)

[Claims] 1. Young's modulus (Mi) is 700 to 2500 k.
A g / mm ² aromatic polyamide or polyimide film, the Young's modulus (Mi) and the dimensional difference rate dL (%) in the length direction satisfy the following general formula (1):
And the ratio of the thickness variation to the average thickness of the film is 0
A high-rigidity long film of -5%. 0 ≦ dL ・ Mi ≦ 100% ・ kg / mm ² (1)