JP2007022042A - Manufacturing method of polymer film and utilization of polymer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a polymer film having almost no physical property difference in its flow direction and width direction and excellent in the uniformity of various physical properties, and the utilization of the polymer film. <P>SOLUTION: In the manufacturing method of the polymer film, the central part 120 of a gel film comprising a high-molecular resin can be allowed to retreat forcibly because the stress opposing the shrink force produced in the central part 120 of the gel film within a heating over is applied to the central part of the gel film by a stress applying part 320 in a state that both end parts 110 of the gel film comprising the high-molecular resin are fixed. Accordingly, the bowing phenomenon caused at the time of baking of the gel film can be suppressed and various physical properties can be uniformized in both of the flow direction and width direction of the film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a polymer film and use thereof, and in particular, a method for producing a polymer film having high uniformity of physical properties in both the flow direction (MD direction) and the width direction (TD direction) of the film. And its use.

Conventionally, polymer films have been used for materials such as flexible printed wiring boards and TAB carrier tapes. For example, a polyimide film has heat resistance, insulation, solvent resistance, low temperature resistance, and the like, and is widely used as a support for computer and IC-controlled electrical / electronic equipment component materials.

  On the other hand, in recent years, miniaturization and weight reduction of computers and IC-controlled electric / electronic devices have been promoted, and miniaturization and weight reduction have been required for wiring boards and IC package materials. Furthermore, the wiring patterns applied to them are becoming finer. Therefore, higher dimensional stability has been demanded in the polymer film to meet the above demand.

  In the case of a film made of a polymer material that is difficult to be melt-processed such as a polyimide film, the following continuous molding method is used for its production. That is, first, the polymer material is dissolved in a solvent such as an aprotic polar solvent to form a solution. A curing agent such as a dehydrating agent and various catalysts is added thereto, and then cast or coated on a support such as a belt or a drum by a die casting method or a coating method. Thereafter, heating, reaction, and drying are performed to obtain a self-supporting film (hereinafter also referred to as “gel film”). Furthermore, the gel film is peeled off from the support, and after fixing both ends of the gel film with pins or the like, the final polymer film is obtained by passing through a heating furnace while transporting the film. .

  However, in the manufacturing method as described above, both ends of the film are held by the holding means in the heating furnace. Therefore, the lateral shrinkage (substantially synonymous with transverse stretching) caused by the evaporation of the solvent contained in the film and the longitudinal shrinkage stress caused by the transverse shrinkage are both ends of the film. Then, it is restrained by the gripping means.

  On the other hand, the restraining force by the gripping means is relatively weak at the central portion of the film. Therefore, due to the influence of the shrinkage stress, a delay occurs in the central portion of the film with respect to both side ends of the film held by the holding means, and the central portion of the film tends to move. If it says easily, if a straight line is drawn along the horizontal direction on the surface of the said gel film, this straight line will deform | transform in the case of lateral stretching. Specifically, the film is deformed into a convex shape in the region at the beginning of the transverse stretching with respect to the film traveling direction, returns to a straight line in the region immediately before the end of the transverse stretching, and is deformed into a concave shape after the end of the transverse stretching. Furthermore, the concave deformation reaches a maximum value when heated in a furnace. As a result, a concave deformation remains in the obtained film. This phenomenon is called the Boeing phenomenon. This bowing phenomenon causes non-uniform physical properties in the width direction of the film, particularly optical characteristics such as orientation angle distribution, mechanical characteristics, humidity expansion coefficient, thermal expansion coefficient, and thermal contraction ratio.

  Such a difference in characteristics in the film plane causes a quality difference, particularly a dimensional change, depending on the location and direction in the film plane during film processing. This is a serious problem in applications such as precision parts, for example, applications such as circuit-forming base materials and recording media. Therefore, there is a demand for technical improvement for ensuring the isotropy of characteristics in the film plane.

  Therefore, several proposals have been made to eliminate such a difference in physical properties in the width direction in thermoplastic films. For example, a method in which a nip roll is provided between transverse stretching and heat treatment to forcibly advance the central portion (see Patent Document 1); in a method for producing a stretched film that is heat-set at a glass transition temperature or higher, Method of extending the heat setting time from the center of the film toward the end of the film in the width direction of the film (see Patent Document 2); Production of a stretched film in which the film is heat-set at or above the glass point transfer temperature In the method, in the process of raising the film temperature to the heat fixing temperature, a method of differentiating the temperature raising rate depending on the position in the width direction of the film (see Patent Document 3); A method of heating so that the temperature of the end portion is higher (see Patent Document 4) has been proposed.

In addition, as a means for suppressing the bowing phenomenon of the polyimide film, for example, a method of determining the heating furnace temperature after observing the occurrence state of the bowing phenomenon of the film (see Patent Document 5); In a heating furnace, a method in which the gel film is not heated above the boiling point of the main volatile component at the same length as the film width from the fixed film end to the in-furnace method (see Patent Document 6); A method of stretching 1 to 1.9 times and then stretching in the width direction at a temperature of 400 ° C. or less at a magnification of 0.9 to 1.3 times the stretching ratio in the traveling direction has been proposed (see Patent Document 7). .
Japanese Examined Patent Publication No. 63-24459 (published February 1, 1988) Japanese Patent Laid-Open No. 2002-137286 (published on May 14, 2002) JP 2002-18948 A (published January 22, 2002) JP-A-6-262676 (published on September 20, 1994) JP 2002-154168 A (published on May 28, 2002) Japanese Patent Laid-Open No. 8-230063 (published on September 10, 1996) JP-A-5-237828 (published September 17, 1993)

  However, the techniques disclosed in Patent Documents 1 to 4 relate to thermoplastic films such as polyester. Therefore, it is difficult to apply to a film made of a polymer material that is difficult to be melt-processed such as a polyimide film. That is, there is a problem that the same effect as in the case of polyester or the like cannot be obtained.

  In the methods of Patent Documents 5 to 7, the bowing phenomenon can be controlled somewhat, but various characteristics in the width direction of the film can be obtained without impairing optical characteristics, thermal dimensional stability, mechanical characteristics, flatness, and the like. The physical properties cannot be made uniform. Furthermore, in these methods, there arises a problem that the apparatus becomes large.

  The present invention has been made in view of the above-mentioned problems, and the object thereof is a method for producing a polymer film having almost no physical property difference in both the flow direction and the width direction of the film and having excellent uniformity of various physical properties. And to provide its use.

  As a result of intensive studies in view of the above-mentioned problems, the inventors of the present invention heated the gel film and dried, cured, or baked, when inserted into a heating furnace, the central portion of the film was more than the opposite ends of the film. The present invention was completed by uniquely finding that the bowing phenomenon can be suppressed by delaying the insertion into the heating furnace.

  That is, the method for producing a polymer film according to the present invention is a method for producing a polymer film using a gel film made of a polymer resin. And a step of drying, curing, or firing the gel film by heating the gel film while passing through the heating furnace, and both ends of the gel film. In a state in which the gel film is fixed, the gel film is loaded with a stress against the shrinkage force generated in the center of the gel film in the heating furnace.

  In the method for producing the polymer film, it is preferable to apply the stress to the center of the gel film by a stress loading means.

  Further, the stress load means is preferably a nip roll.

  Moreover, in the manufacturing method of the said polymer film, it is preferable that the width | variety of the said gel film center part hold | maintained by the said stress load means exists in the range of 1-75% of a film both-ends fixed distance.

  The polymer resin is preferably polyimide.

  Furthermore, the elastic modulus of the polymer film made of the polymer resin is preferably 3 GPa or more.

  A film manufacturing apparatus according to the present invention is a film manufacturing apparatus for continuously manufacturing a polymer film by heating, drying, curing, or baking a gel film made of a polymer resin. Film fixing means for fixing, and stress loading means for applying stress to the gel film central part against the contraction force generated in the gel film central part in the heating furnace while the both ends of the gel film are fixed. It is characterized by providing.

  The stress load means is preferably a nip roll.

  The stress loading means preferably applies the stress to the central portion of the film having a width within a range of 1 to 75% of the fixed distance between both ends of the film.

  In the method for producing a polymer film according to the present invention, stress is applied to the center of the gel film in a state where both ends of the gel film are fixed, and the center of the gel film is forcibly moved backward. Therefore, it is possible to suppress the occurrence of the bowing phenomenon that occurs when firing with the film both ends fixed in a heating furnace. Therefore, there is an effect that a polymer film having high uniformity of physical properties can be obtained in both the flow direction and the width direction of the film.

  An embodiment of the present invention will be described as follows, but the present invention is not limited to this.

<I. Polymer film>
The polymer film according to the present invention has excellent uniformity with little difference in physical properties along the film flow direction (hereinafter also referred to as “MD direction”) and the width direction (hereinafter also referred to as “TD direction”). It is a polymer film. More specifically, in the plane of the polymer film, the linear expansion coefficient and the maximum elastic modulus from the MD direction, the TD direction, the MD direction to the right 45 ° direction, and the MD direction to the left 45 ° direction; The ratio to the minimum value (maximum value / minimum value) is preferably 1.3 or less.

  In the present invention, the polymer film is preferably a polymer film having high linearity, in other words, having a high elastic modulus. Specifically, the elastic modulus of the polymer film is preferably 3 GPa or more. Such a polymer film has strong in-plane orientation during the heating process, and since the orientation has a great influence on the characteristics, a great effect can be obtained by the production method of the present invention. The elastic modulus of the polymer film can be measured according to ASTM D882.

  Moreover, by setting it as the said structure, the polymer film concerning this invention can be used suitably for the base film for flexible printed wiring boards, and / or the coverlay film for flexible printed wiring boards.

  In addition, when the film can be processed directly by heating and melting, the problem of in-plane orientation in the heating process does not occur, so the polymer film according to the present invention is a polymer film that cannot be processed by heat melting. Preferably there is.

Specifically, aromatic polyimide, aromatic polyamide, aromatic polyester, polybenzoxazole, polybenzothiazole, polybenzimidazole, polyarylate, polyphenylene sulfide, polyether sulfone, polyether ketone, polyether ether ketone, Examples thereof include films of other liquid crystalline polymers and various ladder polymers.
The shape of the polymer film is not particularly limited, but the effect of the present invention is particularly easily obtained when the thickness of the film is 1 to 500 μm. Furthermore, a remarkable effect is obtained in the film width when the gel film is continuously produced at 500 mm or more.

<II. Production method of polymer film>
The present inventors have analyzed the cause of the difference in physical properties along the width direction of the polymer film when the polymer film is produced by heating, drying, curing, or baking the gel film. As a result, immediately after being transported to the heating furnace with both ends of the gel film fixed, the center of the gel film shrinks evenly within the plane as the organic solvent contained in the gel film evaporates. I understood. On the other hand, since the gel film end portion is restrained by the fixing means, uniform shrinkage does not occur in the plane. From the above, the difference in physical properties occurs in the vicinity of the end of the polymer film because the shrinkage of the gel film due to evaporation of the organic solvent contained in the gel film is different between the center and the end of the gel film. It became clear that.

  Then, the manufacturing method of the polymer film concerning this invention fixes the gel film both ends, the process (henceforth a "film fixing process") which inserts the said gel film in a heating furnace, and said gel film A step of drying, curing, or baking the gel film by heating while passing through a heating furnace (hereinafter also referred to as a “baking step”). In the film fixing step, the gel film Any method may be used as long as both ends are fixed and the gel film is subjected to a stress against the contraction force generated in the center of the gel film in the heating furnace. Other specific configurations are particularly limited. is not. For example, in addition to the above-described configuration, a step of forming a polymer resin into a gel film (hereinafter also referred to as “gel film forming step”) may be included.

  According to the said structure, the polymer film described by said <I> item can be manufactured suitably. That is, the present invention can be applied to the production of any polymer film as long as the in-plane orientation of molecular chains of the film proceeds in the course of heating.

  Hereinafter, each of the above steps will be described in detail.

(II-1. Gel film forming step)
The gel film forming step is a step of forming a polymer resin into a gel film. The gel film preferably contains a volatile component. In the present specification, the “volatile component” refers to a substance that is contained in the gel film and that decreases in amount in the polymer film after the baking process. That is, the volatile component is not particularly limited, and is an organic solvent used for dissolving the polymer resin and its raw material, water generated in the process of forming the polymer resin into a gel film, polymer Dehydrating agents and / or cyclization catalysts used to cure the resin are included. Examples of the organic solvent include dimethyl sulfoxide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone and dimethylsulfone. It can be illustrated.

  In the present invention, the content of volatile components in the gel film (hereinafter also referred to as “volatile component content”) is preferably 15 to 200%.

  In addition, a volatile component content rate is represented by a following formula.

Volatile component content = {(volatile component content weight of polymer resin film) / (solid content weight of polymer resin film material)} × 100 (%) = {(volatile component content weight in gel film) / (Solid content in gel film)} × 100 (%)
When the volatile component content in the gel film is 15% or less, the strength of the film in the heating furnace tends to be significantly reduced. Therefore, the film may tear in the heating furnace, and the film may not be manufactured stably. Moreover, when it is 200% or more, the variation in the volatile component content in the width direction of the film tends to increase in the gel film. Therefore, it is difficult to obtain a film having uniform physical properties in the width direction.
Moreover, the mechanical characteristic of the said gel film is not specifically limited, What is necessary is just to have the self-supporting property which can be conveyed by roll-to-roll.

  Further, the method for forming the polymer resin into the gel film is not particularly limited with respect to the specific steps, materials, conditions, equipment used, equipment used, etc. Accordingly, it may be appropriately selected. For example, the polymer resin may be formed into a film (gel film) in a state in which the polymer resin has a volatile component or a reaction that causes shrinkage by heating.

  More specifically, when the polymer resin is a polyimide resin, the polyimide resin can be formed into a gel film as follows. When the polyimide resin is formed into a gel film, first, a polyamic acid organic solvent solution which is a polyimide precursor is prepared. Next, the prepared polyamic acid organic solvent solution is imidized to form a film. Thereby, a gel film of polyimide is obtained. The method for preparing the polyamic acid organic solvent solution and the method for imidizing the polyamic acid solution are as follows.

(A) Preparation of Polyamic Acid Organic Solvent Solution The polyamic acid organic solvent solution used in the present invention is prepared by combining an organic diamine component and an organic tetracarboxylic dianhydride, such as N, N-dimethylformamide, by a conventionally known method. It is obtained by reacting (polymerizing) in an organic solvent, and its structure is not particularly limited. However, when the polyimide film obtained in the present invention is used for a base film for a flexible printed wiring board and / or a coverlay film for a flexible printed wiring board as a main application, paraphenylenediamine that exhibits extremely high linearity is used as the total diamine. A polyimide film synthesized using 25 mol% or more based on the components and / or 25 mol% or more of pyromellitic dianhydride based on the total acid dianhydride component is preferable. By setting it as the said structure, the elasticity modulus of the polyimide film obtained can be 3.0 GPa or more.

  As the solvent used in the above reaction (polymerization), dimethyl sulfoxide, N, N-dimethylacetamide, N, N′-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2 -Pyrrolidone and dimethylsulfone are mentioned. These compounds are preferably used alone or in combination.

  The polyamic acid concentration of the polyamic acid organic solvent solution obtained by the above reaction (polymerization) is preferably adjusted to 10 to 30% by weight.

(B) Imidation of Polyamic Acid Next, a method for obtaining a polyimide gel film from a polyamic acid organic solvent solution will be described. By cyclizing the polyamic acid using the above polyamic acid organic solvent solution, a polyimide gel film is obtained. In the present invention, the method of cyclizing the polyamic acid is not particularly limited, and is a method of chemical cyclization using a cyclization catalyst and a dehydrating agent (hereinafter also referred to as “chemical ring closure method”), and thermal. Any of the methods of dehydration and cyclization (hereinafter also referred to as “thermal ring closure method”) may be used. Note that productivity is better when the chemical ring closure method is used than when the thermal ring closure method is used.

  Examples of the dehydrating agent used in the chemical ring closure method include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as phthalic anhydride. These dehydrating agents are preferably used alone or in combination. Examples of the cyclization catalyst include heterocyclic tertiary amines such as pyridine, picoline, and quinoline, aliphatic tertiary amines such as triethylamine, and aromatic tertiary amines such as N, N-dimethylaniline. Secondary amines and the like. These cyclization catalysts are preferably used alone or in combination.

  As a method for producing a polyimide gel film using a chemical ring closure method, (1) a cyclization catalyst and a dehydrating agent are mixed in a polyamic acid solution and imidized, and then on a metal support having a smooth surface. And a method for obtaining a polyimide gel film by casting the solution, and (2) imidation by coating the polyamic acid solution to form a thin film and then immersing it in a mixture of a cyclization catalyst and a dehydrating agent. For example, there is a method of obtaining a polyimide gel film. The method (1) is preferred because a polyimide gel film uniform in the thickness direction can be obtained.

  In the above method (1), before the polyamic acid organic solvent solution, the dehydrating agent and the cyclization catalyst are mixed before being cast-coated on a metal support having a smooth surface, dimethyl sulfoxide is used in advance. , N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone, or dimethylsulfone, and a dehydrating agent A mixed solution prepared with the cyclization catalyst is prepared. Thereafter, mixing the mixed solution with the polyamic acid organic solvent solution is preferable because the mixing property between the dehydrating agent / cyclization catalyst and the polyamic acid organic solvent solution is improved. The mixing ratio of the mixed solvent and the polyamic acid organic solvent solution is preferably 20 to 100 parts by weight, and preferably 30 to 80 parts by weight with respect to 100 parts by weight of the polyamic acid organic solvent solution. It is more preferable. By mixing at the above ratio, the thickness of the obtained film is preferably uniform in the width direction.

  In the method of (1), the mixed solution containing the polyamic acid organic solvent solution, the dehydrating agent, and the cyclization catalyst is continuously cast on the surface of a metal support having a smooth surface to form a thin film of the solution. To form. Then, the gel film (self-supporting film) of polyimide can be obtained by heat-drying the thin film for about 2 to 20 minutes at 60 to 160 ° C. and peeling it off from the metal support. Thus, the content rate of the volatile component which consists of the said solvent and produced | generated water | moisture content in the polyimide gel film obtained, ie, a volatile component content rate, is about 15 to 200%.

(II-2. Gel film fixing step)
In the method for producing a polymer film according to the present invention, the gel film made of a polymer resin is preferably conveyed to a heating furnace by roll-to-roll as shown in FIG. In the gel film fixing step, both ends of the gel film made of a polymer resin may be fixed, and the specific configuration is not particularly limited. For example, the gel film obtained in the gel film forming step may be peeled off from the metal support, transported to the film fixing means by roll-to-roll, and both ends of the gel film may be fixed by the film fixing means. At this time, it is preferable to fix the gel film by the film fixing means at a position within 100 mm from the end of the gel film.

  The film fixing means can be realized by a film gripping device attached to a chain driven along the rail.

  Furthermore, in the gel film fixing step, the film insertion angle when the gel film is inserted into the film fixing means is preferably 20 ° or less. If the film insertion angle is within the above range, both ends of the gel film can be stably fixed by the film fixing means.

  Furthermore, in the gel film fixing step, after fixing both ends of the gel film as described above, the stress against the shrinkage force generated in the center of the gel film in the heating furnace is applied while the both ends of the gel film are fixed. It is preferable to load the center of the gel film. Specifically, what is necessary is just to slow down the film conveyance speed of a gel film center part with respect to the film conveyance speed of the gel film both ends. If it is the said structure, the said gel film center part can be forced to reverse. Therefore, after the gel film fixing step, when the baking step (details will be described later) is continuously performed, the timing of conveyance to the heating furnace may be shifted between the gel film both ends and the gel film central portion. it can. More specifically, the center part of the gel film can be delayed from both ends of the gel film and conveyed to the heating furnace. Therefore, a film having uniform physical properties in the width direction of the film can be obtained.

  The stress is preferably applied by stress loading means, but the stress loading means is not particularly limited as long as it can apply desired stress. For example, a nip roll etc. are mentioned. More specifically, after the gel film fixing step, the center of the gel film is held by a nip roll while the gel film is fixed to the film fixing means (see FIG. 2), whereby the stress is applied to the center of the gel film. What is necessary is just to reversely move the gel film center part forcibly.

  Furthermore, it is preferable to use the width | variety of the gel film center part which loads the said stress within the range of 1-75% of the film both ends fixed distance. That is, when a nip roll is used to apply the stress to the gel film center, the width of the nip roll that holds the gel film in the center of the gel film, in other words, the roll width of the nip roll is 1 of the fixed distance at both ends of the film. It is preferable to be within a range of ˜75%. If it is in the said range, the uniformity of the physical property of a film TD direction can be maintained.

  In addition, in this specification, the said "film both-ends fixed distance" means the distance between the both ends of the film currently fixed by the film fixing means (refer FIG. 1).

  Moreover, when using a nip roll in order to load the said stress, the material of the said nip roll is although it does not specifically limit, The thing with the tolerance with respect to the organic solvent contained in a gel film is preferable. Specifically, a combination of a metal mirror surface and a rubber elastic body, or a combination of a metal mirror surface and a metal mirror surface is preferable. The material of the rubber is preferably a fluororesin system from the viewpoint of resistance to the organic solvent.

  Furthermore, when the nip roll is used to apply the stress, the method for controlling the nip roll is not particularly limited as long as the stress can be applied. For example, a control method using a driving method or a nip pressure method with a free roll can be preferably used. By setting it as the said structure, a gel film center part can be delayed rather than a gel film both ends, and can be conveyed to a heating furnace.

  When the nip roll is controlled by a driving method, the nip roll speed is controlled to be slower than the tenter film conveyance speed. Specifically, the nip roll speed is preferably controlled within a speed range of 0.01% to 10% reduction of the tenter film conveyance speed. When the nip roll is rotated at a speed slower than the 10% reduction, the gel film may fall off from the film fixing means, the gel film may be broken, or scratches may occur on the film surface. . Further, when the nip roll is rotated at a speed faster than the speed of 0.01% reduction, the uniformity of physical properties in the TD direction may be impaired.

  Moreover, when controlling a nip roll by a nip pressure system, it is preferable to make a nip pressure into the range of 0.1-50 kgf. In the above range, even if the nip roll does not have a driving force, the same effect as in the case of controlling the nip roll by the driving method as described above can be obtained by its own weight. That is, the nip roll speed can be controlled to be slower than the tenter film conveyance speed. On the contrary, if it deviates from the above range, the uniformity of physical properties in the TD direction is impaired, the gel film falls off the film fixing means, the gel film is torn, or the film surface is scratched. May occur.

  Moreover, when a gel film is conveyed to a heating furnace by roll-to-roll, if a gel film is exposed to high temperature, a gel film will shrink in the width direction of a film, and the uniformity of the physical property of a film TD direction will be impaired. . Therefore, the gel film is preferably transported in a state of 50 ° C. or lower, and more preferably transported in a state of 30 ° C. or lower. That is, the temperature of the gel film in the gel film fixing step is preferably maintained at 50 ° C. or lower, and more preferably maintained at 30 ° C. or lower.

(II-3. Firing step)
In the gel film fixing step, the gel film is fixed to the film fixing means and conveyed to a heating furnace, and then dried / heat treated in the baking step to obtain a polymer film. At this time, a known method may be used as the method for heating the film. For example, as the heating furnace, a hot air furnace, a far infrared heater furnace (also referred to as a far red furnace or an IR furnace), a continuous heating furnace including a heating furnace, a hot air furnace, an IR furnace, and a slow cooling furnace can be used.

  In drying / heating in the heating furnace, the temperature of the first heating furnace in which the gel film is first transported is preferably less temperature unevenness in the film width direction. When the temperature unevenness is large, the generation of shrinkage stress due to solvent evaporation differs in the film TD direction. As a result, a phenomenon similar to the bowing phenomenon occurs, and a uniform difference in physical properties in the TD direction occurs. Therefore, it is preferable to control the temperature unevenness in a range where the above problem does not occur according to the temperature of the first heating furnace. Specifically, when the set temperature of the first heating furnace is less than 200 ° C., the temperature unevenness, that is, the difference between the maximum temperature and the minimum temperature (maximum temperature−minimum temperature) is 10% or less of the set temperature. Preferably there is. When the set temperature of the first heating furnace is 200 ° C. or higher and lower than 350 ° C., the temperature unevenness is preferably 6% or less of the set temperature. Furthermore, when the set temperature of the first heating furnace is 350 ° C. or higher and lower than 500 ° C., the temperature unevenness is preferably 4% or less of the set temperature.

  Further, if necessary, the film may be stretched in the TD direction by performing a conventionally known expansion / contraction operation. For example, a method of gradually increasing the film width in the first half of the heating furnace and then reducing the film width, A method of increasing the width after reducing the width in the first half can be appropriately used.

  In addition, the heating method in the said baking process is not specifically limited, A conventionally well-known method can be used. Moreover, what is necessary is just to set a heating condition suitably according to the composition of the polymeric resin to be used.

<III. Film production equipment>
The film manufacturing apparatus according to the present invention is a film manufacturing apparatus that continuously manufactures a polymer film by heating, drying, curing, or baking a gel film made of a polymer resin. The specific configuration will be described with reference to FIGS. 1 and 2 as follows. Needless to say, the present invention is not limited to this.

  The film manufacturing apparatus 1 according to the present embodiment has a film fixing part 300 for fixing the gel film 100 and the gel film both ends 110 fixed to the gel film central part 120 in a heating furnace. It is only necessary to include a stress loading portion 320 that applies stress to the gel film central portion 120 with a stress against the generated contraction force, and other specific configurations are not limited. In addition, you may provide the conveyance part (not shown) for conveying the gel film 100 to a heating furnace by roll-to-roll, a heating furnace (not shown), etc.

  The stress load part 320 holds the gel film center part 120 and moves the gel film center part 120 backward while the gel film both ends 110 are fixed by the film fixing part 300. That is, the stress load part 320 is for slowing down the film conveyance speed of the gel film central part 120 with respect to the film conveyance speed of the gel film both ends 110. Thus, when the gel film 100 is transported to the heating furnace while the gel film central part 120 is held by the stress load part 320, the gel film both ends 110 and the gel film central part 120 are transported to the heating furnace. That is, the gel film central portion 120 can be transported after being delayed from the gel film end portion 110.

  The film fixing part 300 preferably fixes the gel film 100 at a position within 100 mm from the end of the gel film 100.

  Moreover, in the gel film center part 120, it is preferable that the width | variety hold | maintained by the said stress load part 320 is the range of 1%-75% of the film both ends fixed distance 130. By setting it as the said structure, it can suppress that the uniformity of the physical property of a film TD direction is impaired.

  The shape and material of the stress load part 320 are not particularly limited. For example, a nip roll can be used. In this case, the nip roll is provided so as to contact the gel film central portion 120. The nip rolls are a pair of two nip rolls, and the gel film 100 is sandwiched between the two rolls, and the stress is applied to the gel film central portion 120 (see FIG. 2). When using a nip roll as the stress load part 320, what was illustrated by said <II-2> term can be used suitably similarly.

  Moreover, when using a nip roll as the said stress load part 320, the control system is not specifically limited, The system illustrated by said <II-2> term can be used suitably.

  Moreover, the film manufacturing apparatus 1 according to the present embodiment may include a temperature control unit (not shown) for controlling the temperature of the gel film 100 inserted into the heating furnace. The temperature control unit preferably controls the temperature of the gel film 100 to 50 ° C. or lower, and more preferably controls to 30 ° C. or lower. When the film production apparatus 1 is used for carrying out the polymer film production method, the gel film 100 is transported to a heating furnace by roll-to-roll. Are not exposed to high temperatures. Therefore, the gel film 100 can be prevented from shrinking in the width direction of the film, and the uniformity of physical properties in the film TD direction can be impaired, or the thickness unevenness in the width direction of the film can be prevented.

  The film manufacturing apparatus 1 may further include a guide roll 200. When the guide roll 200 is provided, the guide roll 200 is preferably installed such that the distance to the film fixing unit 300 is within twice the width of the gel film 100. Thereby, the gel film 100 can be stably inserted into the film fixing part 300 and fixed.

  As described above, the polymer film manufacturing apparatus according to the present invention is configured so that the gel film is fixed to the center of the gel film with the gel film both ends fixed before the gel film both ends are fixed. Since it is the structure which applies stress and reverses the said gel film center part, it can use suitably in order to implement the manufacturing method of the polymer film concerning this invention.

  The present invention is not limited to the configurations described above, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments are appropriately combined. The obtained embodiment is also included in the technical scope of the present invention.

  The present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to this. Those skilled in the art can make various changes, modifications, and alterations without departing from the scope of the present invention. The linear expansion coefficients in the following examples and comparative examples were evaluated as follows.

[Linear expansion coefficient]
The temperature was raised from room temperature to 400 ° C. at a temperature rising rate of 10 ° C./min under a nitrogen stream using a thermomechanical analyzer (trade name: TMA120C, manufactured by Seiko Instruments Inc.), and then cooled to room temperature. Furthermore, it heated up from room temperature to 400 degreeC with the temperature increase rate of 10 degree-C / min, and calculated | required the average value in the range of 100-200 degreeC at the time of the 2nd temperature increase. In addition, as schematically shown in FIG. 3, the film was sampled from three points (both ends and center) of A, B, and C in the TD direction of the polymer film. In addition, the linear expansion coefficient of the film sampled from three points of A, B, and C is MD direction, TD direction, 45 ° right direction from the MD direction (referred to as 45 ° right direction in Table 2), and The linear expansion coefficients in four directions (see FIG. 3) in the left 45 ° direction (referred to as the left 45 ° direction in Table 2) were measured.

[Synthesis Example 1: Production of polyimide gel film]
Pyromellitic dianhydride / p-phenylenebis (trimellitic acid monoester acid anhydride) / 4,4′-diaminodiphenyl ether / paraphenylenediamine in a molar ratio of 1/1/1/1 respectively. , N′-dimethylacetamide was polymerized in a solvent so that the solid content was 18%.

  After cooling this polymerization solution to about 0 ° C., a mixed solvent of acetic anhydride / isoquinoline / N, N′-dimethylacetamide was added to 100 parts by weight of the polyamic acid organic solvent solution in the polyamic acid organic solvent solution cooled to about 0 ° C. After adding 50 parts by weight to the mixture and sufficiently stirring, the mixture was extruded from a die maintained at about 5 ° C. and cast onto an endless belt. Then, it heated and dried and obtained the gel film with a volatile component content rate of 80%.

  In addition, the volatile component content rate was calculated | required by the following formula.

Volatile component content = (a−b) ÷ b × 100 (%)
(In the formula, a represents the weight of the gel film, and b represents the weight after drying of the gel film (drying conditions are 400 ° C./10 minutes).)
[Examples 1-3: Production of polyimide film]
The gel film (width: 540 mm) having the self-supporting property of Synthesis Example 1 was peeled off and conveyed to the induction roll by roll-to-roll. Subsequently, both ends of the gel film (sheet) are fixed to a pin sheet that continuously conveys the gel film (sheet) (film both ends fixing distance 500 mm), and then the gel is formed with a free-roll metal (SUS) nip roll. The gel film was conveyed to a hot-air heating furnace, a far-infrared furnace, and a slow cooling furnace while holding the center of the film. And when it carried out from the slow cooling furnace, the film was peeled off from the pin, and it wound up, and obtained the 12.5 micrometer polyimide film of about 470 mm width.

  The width of the free roll metal (SUS) nip roll and the nip pressure after fixing both ends of the gel film are as shown in Table 1.

  Furthermore, Table 1 shows the atmospheric temperatures and residence times of the heating furnace (1 to 4 furnaces: hot air furnace), the far-red furnace, and the slow cooling furnace. The width of the film was constant in the heating furnace.

  The linear expansion coefficient was measured about the polyimide film obtained as mentioned above. The results are shown in Table 2.

[Comparative Example 1]
A polyimide film was produced in the same manner as in Example 1 except that no nip roll was used.

[Comparative Example 2]
A polyimide film was produced in the same manner as in Example 1 except that the width of the nip roll was 400 mm and the nip pressure was 80 kgf. However, the gel film was torn by the film both ends gripping device, and the gel film could not be conveyed to the heating furnace.

[Comparative Example 3]
The polyimide film was driven in the same manner as in Example 1 except that the nip roll was driven, the roll width was 100 mm, the nip speed was 5% higher than the tenter film conveyance speed, and the nip pressure was 1.0 kgf. A film was produced.

  That is, in Comparative Example 3, the nip roll is a driving method, and the nip speed is higher than the tenter film conveyance speed. In this case, since the stress in the same direction as the shrinkage force generated in the center of the gel film is applied in the heating furnace, the effect of the present invention, that is, a polyimide film having uniform physical properties in the TD direction and the MD direction cannot be obtained. (See Table 2).

  Note that the present invention is not limited to the configurations described above, and various modifications are possible within the scope of the claims, and technical means disclosed in different embodiments and examples respectively. Embodiments and examples obtained by appropriately combining them are also included in the technical scope of the present invention.

  As described above, the polymer film manufactured by the method for manufacturing a polymer film according to the present invention has optical characteristics, mechanical characteristics, humidity expansion coefficient, thermal expansion coefficient, and heat along the width direction of the film. There is almost no difference in physical properties such as shrinkage and excellent uniformity. Therefore, the present invention can be used not only for applications such as precision parts, such as base materials for circuit formation and recording media, but also for fields related to the manufacture of electronic parts using polymer films. It is possible.

It is a perspective view which shows typically the principal part of the manufacturing apparatus of the film in embodiment of this invention. It is sectional drawing which shows typically the principal part of the manufacturing apparatus of the film in embodiment of this invention. In the Example of this invention, it is a perspective view which shows typically the sampling of the film for the linear expansion coefficient measurement of a film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film production apparatus 100 Gel film 110 Gel film both ends (gel film end)
120 Gel film central part 130 Film both ends fixing distance 200 Guide roll 300 Film fixing part (film fixing means)
310 End fixing jig 320 Stress load part (nip roll, stress load means)

Claims (9)

In the polymer film manufacturing method of manufacturing a polymer film using a gel film made of a polymer resin,
Fixing both ends of the gel film and inserting the gel film into a heating furnace;
Heating the gel film while passing through a heating furnace, thereby drying, curing, or baking the gel film, and
A method for producing a polymer film, comprising applying a stress against a contraction force generated in a central portion of the gel film in a heating furnace to the central portion of the gel film in a state where both ends of the gel film are fixed.   The method for producing a polymer film according to claim 1, wherein the stress is applied to a central portion of the gel film by a stress loading means.   The method for producing a polymer film according to claim 2, wherein the stress load means is a nip roll.   The width of the gel film central portion to which the stress is loaded by the stress loading means is within a range of 1 to 75% of a fixed distance between both ends of the film. Method for producing molecular film.   The manufacturing method according to claim 1, wherein the polymer resin is polyimide.   6. The production method according to claim 1, wherein the polymer film made of the polymer resin has an elastic modulus of 3 GPa or more.   In a film manufacturing apparatus for continuously manufacturing a polymer film by heating, drying, curing, or baking a gel film made of a polymer resin, a film fixing means for fixing the gel film, A film manufacturing apparatus comprising stress loading means for applying a stress against the shrinkage force generated at the gel film central portion in the heating furnace to the gel film central portion in a state where both ends of the gel film are fixed. .   The film manufacturing apparatus according to claim 7, wherein the stress load means is a nip roll.   The said stress load means loads the said stress to the center part of the film of the width within the range of 1-75% of the film both ends fixed distance, The manufacturing apparatus of the film of Claim 7 or 8 characterized by the above-mentioned.

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