JP5565183B2 - Film production method - Google Patents

Description

  The present invention relates to a method for producing a film having a small thickness unevenness, more specifically, a film that is produced in a long shape and is wound around a roll.

As a method of manufacturing a polyimide film,
(1) A polyamic acid solution or a polyamic acid solution composition in which an imidization catalyst, an organic phosphorus-containing compound, inorganic fine particles, etc. are selected and added to a polyamic acid solution as necessary is cast on a support in the form of a film. , After drying by heating to obtain a self-supporting film, thermally dehydrating cyclization, removing solvent to obtain a polyimide film, and (2) adding a cyclization catalyst and a dehydrating agent to the polyamic acid solution, and further required A polyamic acid solution composition selected by adding inorganic fine particles depending on the condition is cast on a support, chemically dehydrated and cyclized, and heated and dried as necessary to form a self-supporting film. After obtaining the above, there is known a method of obtaining a polyimide film by heating to remove the solvent and imidization.

  In either production method, in the process of casting a polyamic acid solution composition on a support, the polyamic acid solution composition is generally applied on a support such as a belt or a drum by a die having an adjustable lip interval. Cast. The cast solution-like film is imidized by the above-described steps, and the finally produced polyimide film is generally wound into a roll and shipped.

  The polyimide film is used as a wiring board having a metal wiring such as copper formed on the surface, and is further used by mounting a chip such as an IC chip on the wiring board. Therefore, the polyimide film is required to have excellent thickness uniformity in the width direction and the length direction.

As a method for continuously obtaining a polyimide film having a uniform thickness, for example, in Patent Document 1, a solution of polyamic acid, which is a polyimide precursor, is applied on a traveling support, and the applied coating film is dried. In the film forming method, which is a self-supporting film, and peels the self-supporting film from the support and further heat-treats to obtain a polyimide film, the support in the width direction orthogonal to the direction of travel of the support during drying A method for forming a polyimide film is disclosed in which the above temperature is controlled within a central value of ± 5 ° C. In Patent Document 2, a polyamic acid compound is extruded from a die into a sheet shape, and a gel-like film is obtained by chemical ring closure or thermal ring closure. By continuously measuring and feeding back this data, the thickness unevenness in the film width direction (TD) is 3.0% or less, and the TD thickness measured every about 10 m in the film longitudinal direction (MD) is laminated, Adjust the gap of the die so that the difference between the maximum thickness and the minimum thickness of the TD thickness profile obtained by averaging is 2.0% or less of the film average thickness, and further adjust the TD stretch ratio of the film the Young's modulus in the TD is 340 kg / mm ² or more, 5% stretch strength of TD (F-50) is 10 kg / mm ² or more, further tenter Method for producing a polyimide film strip extending in the longitudinal direction of the film length 6.5m, characterized in that the control is performed so that the 9mm or less has been disclosed by adjusting the TD temperature profile.

  On the other hand, there are winding edges, polygonalization, and high edges as defective product rolls of polyimide film. If there is a thick part in the width direction of the film, even if the thickness unevenness is minute, the difference becomes remarkable by being laminated as a scroll, and a high hump is caused. In addition, since the polyimide film is excellent in rigidity, there is a problem that scratches occur when winding deviation occurs in the presence of a hump. Polygonalization is a problem that when a product roll of polyimide film is stored for a long period of time, the film is deformed by stress relaxation and wrinkles are generated. This problem is likely to occur when the product roll hardness of the polyimide film is uneven and the interval between the high hardness portions is wide. The high edge is a problem that a raised portion is generated at the end when the film is cut, and is likely to occur when a slit blade is poorly cut or a locally thick portion of the polyimide film is cut. Any problem is likely to occur when there is a thick portion in the width direction of the polyimide film, and thus it is necessary to reduce the thickness unevenness as much as possible.

  In order to eliminate the hump, in the production of a film that is melt-extruded from a T-die, conventionally, the thickness of the obtained film is measured in the width direction, and the lip interval of the T-die is controlled based on the result. It has been broken.

  For example, in Patent Document 3, as a roll profile control method for a plastic film melt-extruded from an extrusion die, the width direction thickness profile is continuously measured, and the thickness profile is overlapped by the number of windings, A method is described in which the obtained roll profile is estimated and, when the roll profile has an unacceptable deviation, a thickness adjusting operation is applied to the extrusion die position corresponding to that position. In addition, in Patent Document 4, the individual profile measurement values obtained by scanning the thickness meter once or a plurality of times in the film width direction are averaged a plurality of times in the film advancing direction, and the predetermined band width determined from the rigidity of the extruded flexible lip Based on the profile data value set to span, the profile target value is set to at least a predetermined bandwidth so that the maximum value is reduced when the maximum value of the profile data value exceeds a preset maximum limit value. A control method is described in which a hump is not generated by correcting the decrease over time.

  Further, Patent Document 5 discloses that the thickness of the film extruded from the flat die is divided into a plurality of portions in the width direction of the flat die, and the phase is shifted and slightly increased or decreased periodically for each division. Prevention methods are described. In this method, a section whose control target value is larger by ΔT than the target value T and a section whose thickness control target value is smaller by ΔT than the target value T are alternately adjacent to each other. As a result, a slight wave is generated in the winding axis direction. By winding in the hit state, the film can be prevented from being unwound and the occurrence of humps can be suppressed.

JP 2006-168222 A JP 2001/082111 A JP-A-7-108586 JP-A-8-276491 JP-A-3-275324

  In a film manufacturing method in which a film raw material is continuously extruded from a T-die capable of adjusting a lip interval at a plurality of positions to a support, and then dried and heated as necessary. When the thickness unevenness is generated, even if automatic control is performed using the thickness profile of the obtained film, the thickness unevenness is not easily solved.

  An object of this invention is to provide the manufacturing method of a film without the thickness nonuniformity in the width direction or the length direction.

  The resin film for wiring board forms a metal wiring such as copper on the surface, and then other substrates by anisotropic conductive adhesive film (ACF) or metal bonding (for example, gold-gold bonding, gold-tin bonding, etc.) Or a chip member such as an IC chip is mounted. Therefore, a resin film for a wiring board such as a polyimide film is required to have excellent thickness uniformity in the width direction and the length direction. One of the aspects of the present invention is to provide a resin film for a wiring board and a method for producing a film having no uneven thickness in a suitable width direction or length direction.

  In particular, one of the aspects of the present invention is that a T-die capable of adjusting a lip interval at a plurality of positions having an automatic control function using a film thickness profile on a support on which a polyamic acid solution or a polyimide solution is run. The coating film applied is dried, and the coated film is dried to form a self-supporting film. The polyimide film is a resin film for a wiring board obtained by peeling the self-supporting film from the support and further heat-treating it. It aims to provide a method.

  The present invention relates to the following matters.

1. A film manufacturing method having at least one step of continuously extruding a film raw material from a T-die capable of adjusting a lip interval,
When the width direction of the T die is divided into m fine adjustable blocks,
For a given block (k), a control command to alternately increase a lip interval by ΔT and a control command to narrow the lip interval by ΔT with a predetermined period is performed.
Control is performed so that the block (k + 1) adjacent to the arbitrary block (k) performs the same operation as the arbitrary block (k) with a delay of a predetermined period (however, m and k Is a positive integer and satisfies 1 ≦ k <m.)
The film manufacturing method characterized by these.

2. A film manufacturing method having at least one step of continuously extruding a film raw material from a T-die capable of adjusting a lip interval,
When the width direction of the T die is divided into m fine adjustable blocks,
For a specific block (k ₀ ) among the m blocks, a + control command that widens the lip interval by ΔT and a −control command that narrows the lip interval by ΔT alternately with a predetermined period. Control to
In k ₀ from the number of large blocks _(k 0 + i), from adjacent blocks _{(k 0 + i-1)} , delayed by a predetermined time, it performs the same operation as the block _{(k 0),}
In k ₀ of from numbers less block _(k 0 -j), from adjacent blocks _(k 0 -j + 1), delayed by a predetermined time, to perform the same operation as the block _{(k 0)} (where, _{k 0} , I, j are positive integers, m is as defined in 1 above, and each parameter has the following relationship:
1 <k ₀ <m
1 ≦ (k ₀ −j) <k ₀ <(k ₀ + i) ≦ m
Meet. )
The film manufacturing method characterized by these.

  3. The T die capable of adjusting the lip interval is a T die having a profile automatic control function that automatically adjusts the gap width of the extrusion lip of the T die using a film thickness profile measurement value in the film width direction. 3. The film production method according to 1 or 2 above.

  4). 4. The method for producing a film according to any one of the above items 1 to 3, wherein the time between the + control command and the next -control command is equal and periodic.

  5. The delays of a predetermined period between adjacent blocks are shorter than the time between the + control command and the next -control command and the time between the -control command and the next + control command. The film manufacturing method of any one of Claims 1.

  6). The delay of a predetermined period between adjacent blocks is less than half of the time between the + control command and the next -control command and the time between the -control command and the next + control command. 6. The method for producing a film as described in 5 above.

  7). The film raw material is a solution containing a solvent, and at least a part of the solvent is evaporated and removed from the solution film extruded from the T-die. Film manufacturing method.

8). The film to be manufactured is a polyimide film,
The film raw material is a polyimide precursor solution,
8. The method for producing a film according to any one of 1 to 7, further comprising a step of casting the polyimide precursor solution on a support from the T die.

  According to the present invention, it is possible to continuously produce a resin film with small thickness unevenness in the width direction. Therefore, the product roll obtained by winding up the resin film of the present invention can suppress the occurrence of winding bumps and polygonalization.

  The resin film such as a polyimide film produced according to the present invention can be used as a wiring board having a metal wiring such as copper formed on the surface thereof, and further can be used by mounting a chip such as an IC chip on the wiring board.

It is a schematic diagram of the T die generally used for manufacture of a film. It is a typical top view of T die. It is a timing chart of the lip space | interval control command issued with respect to a block (k). It is a timing chart of a lip space | interval control command issued with respect to a block (k) and an adjacent block. It is an example of the time chart of the operation control command with respect to all the blocks. It is an example from which the time chart of the operation control command with respect to all the blocks differs. It is an example from which the time chart of the operation control command with respect to all the blocks differs. It is an example according to 2nd Embodiment of the time chart of the operation control command with respect to all the blocks. It is an example according to 2nd Embodiment of the time chart of the operation control command with respect to all the blocks.

  The film manufacturing method to which the present invention is applied has a step of extruding a film raw material from a T-die capable of adjusting a lip interval at a plurality of positions. Here, as the film raw material, those suitable for the final film to be produced are used. When manufacturing a polyimide film, a film raw material is a polyamic acid solution composition, and when manufacturing a film by melt extrusion molding, it is a melt of the material which comprises a film. The present invention is particularly suitable for a method for producing a polyimide film. However, as long as the film is produced using a T-die, production of other films such as an aramid film, a polyamide film, a polyamideimide film, and a polyesterimide It can be used for films, polyester films, liquid crystal polymer films, polysulfone films and the like. In the following description, the production of a polyimide film will be mainly described as an example.

  FIG. 1 is a diagram schematically showing a T die (also referred to as a flat die or an inline slit) generally used for manufacturing a film. The T-die 10 has a lip composed of an upper lip 12 and a lower lip 11, and the film material is extruded from between the lips. The lip interval (T) is adjusted by the bolt 13.

  FIG. 2 is a schematic plan view of a T die. As shown in FIG. 2, a plurality of bolts 13 are provided in the width direction of the T die, and the lip interval can be controlled by adjusting each bolt. it can. As a result, if it is the manufacture of the extruded film 20, for example, a polyimide film, the width direction profile of the thickness of a film-like solution can be changed, and finally the width direction profile of the thickness of a product polyimide film can be changed. Can do. Further, the bolt 13 can be finely adjusted by automatic control as well as manual operation. As a fine adjustment by automatic control, for example, an automatic fine adjustment system by a heat bolt system that adjusts a lip interval by utilizing thermal contraction by a heater is known. In the present invention, such an automatic fine adjustment system adjusts the bolt to perform temporal control of the lip interval.

  In the present invention, when operating the bolt 13, all the bolts in the width direction are divided into operation blocks. The operation block performs the same movement in response to a lip interval + control command (increase the lip interval T) and a -control command (increase the lip interval T). This is referred to as block (1) to block (m), and an arbitrary block is represented by block (k) (m and k are positive integers, 1 ≦ k <m). The block (k) and the block (k + 1) are adjacent to each other. The block (1) to the block (m) may include an equal number of bolts, or may include an appropriate number that is not equal in consideration of the characteristics of the device used. Good. For example, the same number of bolts except for both ends is included in each block.

  The number of bolts assigned to one block differs depending on the device, and it is sufficient to include at least one or more. However, if many bolts are assigned to one block, the number of blocks (m) in the film width direction becomes small, and thickness unevenness cannot be effectively eliminated. The number of bolts contained in one block is preferably 1 to 10, more preferably 1 to 5.

In the present invention, a certain block (k) is controlled to open / close the lip interval (increase / decrease the interval). Specifically, as shown in the timing chart of FIG. 3, a + control command is issued for the bolt included in the block (k) so as to open the lip interval by ΔT at time t _k 1, and time t _{At k2} , a -control command is issued so as to narrow the lip interval by ΔT. Here, when the + control command is received, the bolt opens the lip interval by ΔT and is maintained until the next command (hereinafter referred to as “+ period”). When the − control command is received, the bolt is only ΔT. The operation of narrowing the lip interval is performed, and this interval is maintained until the next command (hereinafter referred to as -period). Similarly, a positive control command is issued at time t _k 3, a negative control command at time t _k 4, a positive control command at time t _k 5, and a negative control command at time t _k 6. By repeating such a + control command and a -control command, the bolt of the block (k) operates to change the lip interval by a range of ΔT.

  The + control command and the -control command are set so that the thickness of the product film (thickness of one sheet) falls within a predetermined allowable range even when the lip interval is changed.

  Here, the + period and the-period need not be equal in time, but are set to be equal when they are totaled in a certain period. In general, it is preferable to equalize the time of the + period and the next-period, and further, equalize the time of the + period and the next + period, that is, as shown in FIG. It is preferable that the period is periodically repeated at the same time. The time of the + period and the − period is preferably determined depending on the type of film to be manufactured, the manufacturing apparatus, and other manufacturing conditions. For example, it is several seconds (for example, 5 seconds) or longer, preferably 1 minute or longer, and more preferably. Is 5 minutes or more, more preferably 7 minutes or more, for example, 1 day or less, preferably 10 hours or less, more preferably 1 hour or less, and even more preferably 20 minutes or less.

In the first embodiment, in the block (k + 1) adjacent to the block (k), a control command is issued so as to perform the same operation as the block (k) with a delay of a specific time. That is, as shown in the timing chart of FIG. 4, block relative to (k + 1) to the bolt included, + control command at time _{t (k + 1)} 1, at time _{t (k + 1)} 2 - control command, time _{t (k + 1 ) A} control command for performing the same operation as the block (k) is issued, such as + control command at 3, -control command at time t _{(k + 1)} 4, and so on. Accordingly, the delay time of the operation of the block (k + 1) with respect to the operation of the block (k) is always constant. When this delay time is Δt _{(k + 1) −k} ,
Δt _{(k + 1) −k} = t _{(k + 1)} 1−t _k 1 = t _{(k + 1)} 2−t _k 2 =... = T _{(k + 1)} 6-t _k 6 =.
It is.

  Similarly, in the block (k + i) that is i blocks away from the block (k), the same operation as that of the block (k) is performed with a delay of a specific time.

FIG. 5 shows an example of a time chart of operation control commands for all blocks. The delay time Δt _{(k + 1) −k} = t _{(k + 1)} 1−t _k 1 from the adjacent block needs to be at least shorter than the + period and the − period, and is preferably 1 / of the + period and the − period. It is 2 or less, more preferably less than 1/2, further preferably 1/3 or less of the + period and − period, and most preferably 1/5 or less. When the delay time Δt _{(k + 1) −k} from the adjacent block is sufficiently shorter than the + period and the − period, as shown in FIG. 5 in the time chart of the operation of the entire block, the + control command and the −control command Is propagating like a wave from the lower numbered block to the higher numbered block. As a result, it is presumed that local thickness unevenness diffuses so as to flow to adjacent blocks and is eliminated.

FIG. 5 shows an example in which the delay time Δt _{(k + 1) −k} from an adjacent block is constant for all k, but Δt _{(k + 1) −k} (> 0) varies depending on the block. Also good. FIG. 6 is an example in which Δt _{(k + 1) −k} becomes shorter as the block number becomes larger. FIG. 7 is an example in which Δt _{(k + 1) −k} becomes longer as the block number increases. However, the relationship between Δt _{(k + 1) −k} , the + period, and the − period is set to satisfy the above-described relationship (particularly a preferable range).

  In this embodiment (first embodiment), as described above, in the block (k + 1) adjacent to the block (k), the control command is performed so as to perform the same operation as that of the block (k) with a specific time delay. However, in the block (k−1) adjacent to the block (k), the same operation is performed even if the same operation as the block (k) is performed with a delay of a specific time. When the block (k-1) adjacent to the block (k) is delayed by a specific time, in FIG. 5 to FIG. 7, the left and right charts are inverted, that is, the control is performed from the larger block number to the smaller block number. It is only a figure in which the command and the -control command propagate like a wave (it may be considered that block numbers are assigned in order from right to left).

Next, a second embodiment is shown in FIG. In the second embodiment, centering on a specific block (k ₀ ), a block (k ₀ + i) having a number greater than k ₀ is delayed by a specific time from an adjacent block (k ₀ + i−1). , The same operation as that of the block (k ₀ ), while the block (k ₀ -j) having a smaller number than k ₀ is delayed by a specific time from the adjacent block (k ₀ -j + 1), and the block ( A control command is issued so as to perform the same operation as k ₀ ). Here, k ₀ , i, and j are positive integers, and m is the number of blocks as described above. Therefore, each parameter satisfies the following relationship.

1 <k ₀ <m
1 ≦ (k ₀ −j) <k ₀ <(k ₀ + i) ≦ m
That is, in the second embodiment, the _{k 0} from the number of large blocks _(k 0 + i), it performs the same operation as the first embodiment, the smaller block than _{k 0} numbered _(k 0 -j), FIG. 5 to 7 are charts in which left and right are reversed, that is, a diagram in which a + control command and a −control command are propagated like waves from a larger block number to a smaller block number.

In Figure 8, at block _(k 0 + i), the delay time Δt _{(k0 + i)} from the adjacent blocks _{(k 0 + i-1)} - (k0 + i-1) are equal for all i, and the block _(k 0 -j ), The delay time Δt _{(k0−j) − (k0−j} + 1) from the adjacent block (k ₀ −j + 1) is equal for all j, and Δt _{(k0 + i) − (k0 + i−1)} = Δt _{(k0 ) -J)-(k0-j + 1)} , which is one of the preferred forms. However, the delay time may be set differently for each block. For example, the delay time of each block may be set differently depending on different i or j, or Δt _{(k0 + i) − (k0 + i−1)} ≠ Δt _{( k0-j)-(k0-j + 1)} may be set. For example, as shown in FIG. 9, the delay from the adjacent block may be set to increase as the distance from the block k ₀ increases. Although not illustrated, the delay from the adjacent block as the distance from the block k ₀ increases. May be set to be small.

k ₀ can be selected in any block depending on the situation, but is preferably set to a relatively central block. For example, the equation:
m / 5 ≦ k ₀ ≦ 4 m / 5
Preferably satisfy the formula:
m / 4 ≦ k ₀ ≦ 3 m / 4
More preferably, the formula:
m / 3 ≤ k ₀ ≤ 2m / 3
Set to satisfy.

  As described above, in the present invention, the lip interval is automatically controlled as described above regardless of the measurement of the film thickness profile in the film width direction. However, in addition to the automatic control of the lip interval according to the present invention, the control based on the feedback of the measurement of the film thickness profile can be superposed. In other words, the film raw material is continuously extruded from a T-die capable of adjusting the lip interval at a plurality of positions used for normal film production, and the width direction profile of the obtained film is measured and compared with the profile target value. Even if the profile automatic control that automatically adjusts the gap width of the extrusion lip of the T die is performed, if the thickness uniformity in the width direction does not disappear or the thickness unevenness that occurs locally in the width direction does not disappear, By further applying the manufacturing method of the present invention to the profile automatic control, the thickness uniformity in the width direction can be easily eliminated, and the thickness unevenness locally generated in the width direction can be easily eliminated.

  Since the present invention can provide a film with little or no thickness unevenness in the width direction or the length direction, the produced resin film can be used for various applications.

  The resin film produced according to the present invention is used as an insulating substrate material used in metal wiring boards such as FPC, TAB, and COF, as a cover substrate such as a metal wiring or a chip member such as an IC chip, and more It can be suitably used as a base substrate for liquid crystal displays, organic electroluminescence displays, electronic paper, solar cells and the like.

  When used as a substrate for a metal wiring board, a metal wiring such as copper is formed on the surface of a resin film, and then an anisotropic conductive adhesive film (ACF) or metal bonding (for example, gold-metal bonding, gold-tin bonding, etc.) ) Etc., electronic / electrical components can be manufactured by connecting to other substrates or mounting a chip member such as an IC chip.

  A laminated body of resin films can be obtained by laminating an adhesive, a photosensitive material, a thermocompression bonding material or the like on one or both surfaces of the resin film produced according to the present invention. Moreover, metal layers, such as copper, can be provided in the single side | surface or both surfaces of the resin film of this invention directly or through an adhesive layer.

  The product roll obtained by winding up the resin film produced according to the present invention has less humps, and hence less scratches due to the occurrence of winding deviation. And since it is wound up comparatively uniformly, even if it preserve | saves for a long period of time, the extent which becomes polygonal is also small. Moreover, since there is little film thickness nonuniformity, it becomes difficult to generate a high edge.

  Therefore, a product roll in which the resin film of the present invention has a length of 500 m or more, preferably 1000 m to 6000 m, more preferably 1500 m to 5000 m, and particularly preferably 2000 m to 4000 m can be obtained.

<Application to production of polyimide film>
The present invention can be applied to the production of various films and can also be applied to melt extrusion molding, but is more preferably applied to a production method by a solution cast method. This is because even if the lip interval is varied within the range of ΔT, if the film raw material extruded from the T die contains a solvent, the solvent is evaporated and the thickness is reduced, so that the influence on the allowable thickness is small. .

  In particular, it is preferable to apply the present invention to the production of a polyimide film. The manufacturing method of a polyimide film is a first step in which a polyamic acid solution composition (hereinafter referred to as a polyimide precursor solution) is cast on a support to form a self-supporting film, and while transporting the self-supporting film, And a second step (curing step) for heat treatment.

  The present invention is used when a polyimide precursor solution is extruded from a T-die and cast on a support in the first step of producing a polyimide film. By controlling the lip interval of the T-die as described above, the thickness unevenness of the self-supporting film is reduced, and as a result, the thickness unevenness of the polyimide film is reduced. A product with less occurrence of

  The finally produced polyimide film may be composed of one layer or multiple layers having different components. Of the layers constituting the polyimide film, at least one layer is preferably a layer composed of heat-resistant polyimide. As an example of a multilayer structure, a layer composed of thermocompression bonding polyimide is formed on one side or both sides of a layer composed of heat-resistant polyimide, a layer with excellent surface smoothness and a non-slip surface on the other side Examples where the layer is formed with an excellent layer, examples where at least one layer is formed with a layer having excellent transparency or non-transparency, and the like are included. Corresponding to the finally produced polyimide film, the self-supporting film may also be composed of one layer, or may be composed of multiple layers having different polyimide precursor components.

  In the following description, a method for producing a single-layer polyimide film having excellent heat resistance will be described as an example. If a polyimide film is composed of two or more layers and casting by extrusion from a T-die is performed two or more times (separate or simultaneous), all or one or more of the two or more castings are performed, It can be carried out by the method of the present invention.

  The self-supporting film is in a semi-cured state or in a dried state before that. This semi-cured state or a dry state before it means that it is in a self-supporting state by heating and / or chemical imidization. The self-supporting film may be any film that can be peeled off from the support, and the solvent content (heat loss) and imidation ratio may be in any range. The solvent content and imidization rate of the self-supporting film are appropriately set depending on the polyimide film intended for production.

  The polyimide film is obtained by reacting a tetracarboxylic acid component and a diamine component, and can be produced by thermal imidization, chemical imidization, or a method that combines thermal imidization and chemical imidization. .

As a method for producing the polyimide film of the present invention,
(1) A polyamic acid solution or a polyamic acid solution composition in which an imidization catalyst, an organic phosphorus-containing compound, inorganic fine particles, etc. are selected and added to a polyamic acid solution as necessary is cast on a support in the form of a film. , After drying by heating to obtain a self-supporting film, thermally dehydrating cyclization, removing the solvent to obtain a polyimide film,
(2) A cyclization catalyst and a dehydrating agent are added to the polyamic acid solution, and the polyamic acid solution composition added by selecting inorganic fine particles and the like as necessary is cast on a support in a film form. A method of obtaining a polyimide film by dehydrating and cyclizing and heat-drying as necessary to obtain a self-supporting film, followed by heat desolvation and imidization can be mentioned.

<First step>
The first step of casting the polyimide precursor solution on the support to form a self-supporting film will be described first.

  First, a tetracarboxylic acid component and a diamine component are reacted in an organic solvent to synthesize a polyamic acid that is a polyimide precursor. Next, if necessary, an imidation catalyst, an organic phosphorus compound and inorganic fine particles are added to the obtained polyimide precursor solution, and then cast on a support, heated and dried to produce a self-supporting film. To do.

  Examples of the tetracarboxylic acid component include aromatic tetracarboxylic dianhydrides, aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and the like. Specific examples include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 3,3 ′, 4,4′-oxydiphthalic dianhydride, diphenylsulfone-3. , 4,3 ′, 4′-tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1, Aromatic tetracarboxylic dianhydrides such as 1,3,3,3-hexafluoropropane dianhydride are exemplified.

  Examples of the diamine component include aromatic diamines, aliphatic diamines, and alicyclic diamines. Specific examples include p-phenylenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, m-tolidine, p-tolidine, 5-amino-2- (p-aminophenyl) benzoxazole, 4 , 4′-diaminobenzanilide, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3,3 '-Bis (3-aminophenoxy) biphenyl, 3,3'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) ) Biphenyl, bis [3- (3-aminophenoxy) phenyl] ether, bis [3- (4-aminophenoxy) phene Ether], bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 2,2-bis [3- (3-aminophenoxy) phenyl] propane, 2,2-bis [3- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) And aromatic diamines such as phenyl] propane.

  As an example of a combination of a tetracarboxylic acid component and a diamine component, the following 1) to 3) are excellent in mechanical properties, and a film having high rigidity and excellent dimensional stability is easily obtained. It can be suitably used for various substrates.

  1) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine, or p-phenylenediamine and 4,4-diaminodiphenyl ether (for example, PPD / DADE (molar ratio) ) Is preferably 100/0 to 85/15.)).

  2) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride (for example, s-BPDA / PMDA (molar ratio) is 99/1 to 0/100, and 97 / 3-70 / 30, preferably 95/5 to 80/20) and p-phenylenediamine, or p-phenylenediamine and 4,4-diaminodiphenyl ether (for example, PPD / DADE ( The molar ratio) is preferably 90/10 to 10/90.)

  3) pyromellitic dianhydride, p-phenylenediamine and 4,4-diaminodiphenyl ether (for example, PPD / DADE (molar ratio) is preferably 90/10 to 10/90). Combination.

  The combination of the tetracarboxylic acid component and the diamine component is preferably 1) and 2) above, and further 1) above.

  Among them, a tetracarboxylic acid component mainly composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter sometimes simply referred to as s-BPDA) and paraphenylenediamine (hereinafter simply referred to as “s-BPDA”). A polyimide precursor produced from a diamine component whose main component is sometimes abbreviated as PPD) is preferred. Specifically, a tetracarboxylic acid component containing 70 mol% or more of s-BPDA, more preferably 80 mol% or more, particularly preferably 90 mol% or more, and still more preferably 95 mol% or more is preferable, and PPD is 70 mol%. More preferably, the diamine component is more preferably 80 mol% or more, particularly preferably 90 mol% or more, and still more preferably 95 mol% or more. From such a tetracarboxylic acid component and a diamine component, a film having excellent mechanical properties, high rigidity and excellent dimensional stability is easily obtained, and can be suitably used for various substrates such as a wiring substrate.

  Furthermore, other tetracarboxylic acids and other diamines can be used as long as the characteristics of the present invention are not impaired.

  The synthesis of the polyimide precursor is achieved by random polymerization or block polymerization of approximately equimolar aromatic tetracarboxylic dianhydride and aromatic diamine in an organic solvent. May also be mixed with the reaction conditions was keep two or more polyimide precursors in which either of these two components is excessive, the respective polyimide precursor solution together. The polyimide precursor solution thus obtained can be used for the production of a self-supporting film as it is or after removing or adding a solvent if necessary.

  The viscosity of the polyimide precursor solution may be appropriately selected according to the purpose of production, and the polyamic acid (polyimide precursor) solution has a rotational viscosity measured at 30 ° C. of about 100 to 5000 poise, particularly 500 to 4000 poise. More preferably, it is about 1500 to 3500 poise from the viewpoint of workability in handling this polyamic acid solution. Therefore, it is desirable to carry out the polymerization reaction to such an extent that the produced polyamic acid exhibits the above viscosity.

  Examples of the organic solvent for the polyimide precursor solution include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide and the like. These organic solvents may be used alone or in combination of two or more.

  If necessary, an imidization catalyst, an organic phosphorus-containing compound, inorganic fine particles, and the like may be added to the polyimide precursor solution as long as it is thermal imidization.

  If necessary, a cyclization catalyst, a dehydrating agent, inorganic fine particles, and the like may be added to the polyimide precursor solution as long as it is chemical imidization.

  For the imidization catalyst, the organic phosphorus-containing compound, the cyclization catalyst in the case of chemical imidation, the dehydrating agent in the case of chemical imidation, inorganic fine particles, etc., known substances and materials can be used in necessary amounts as appropriate.

  The self-supporting film of the polyimide precursor solution is a support of the polyimide precursor organic solvent solution as described above or a polyimide precursor solution composition in which an imidization catalyst, an organic phosphorus-containing compound, inorganic fine particles, and the like are added. It is manufactured by heating to such an extent that it is cast onto the substrate and becomes self-supporting (meaning a stage prior to a normal curing step), for example, can be peeled off from the support.

  The polyimide precursor solution preferably contains about 10 to 30% by mass of the polyimide precursor. Moreover, as a polyimide precursor solution, the thing whose polymer concentration is about 8-25 mass% is preferable.

  The heating temperature and heating time at this time can be determined as appropriate. In thermal imidization, for example, the heating may be performed at a temperature of 100 to 180 ° C. for about 1 to 60 minutes. In the chemical imidization, for example, heating is performed to a degree of self-supporting at a temperature of 40 to 200 ° C.

  As the support, it is preferable to use a smooth base material, for example, a stainless steel substrate, a stainless steel belt, or the like. For continuous production, an endless base material such as an endless belt is preferable.

  The self-supporting film is not particularly limited as long as the solvent is removed and / or imidized to such an extent that it can be peeled off from the support, but in thermal imidization, the loss on heating is 20 to 50 mass. %, And a weight loss by heating in the range of 20 to 50% by mass and an imidization ratio in the range of 8 to 55% are preferable because the mechanical properties of the self-supporting film are sufficient. In addition, when a coupling agent solution is applied to the upper surface of the self-supporting film, it becomes easy to apply the coupling agent solution cleanly, and the polyimide film obtained after imidization is foamed, cracked, crazed, cracked, cracked. This is preferable because occurrence of cracks or the like is not observed.

  The heating loss of the self-supporting film is a value obtained from the following formula from the mass W1 of the self-supporting film and the mass W2 of the cured film.

  Heat loss (mass%) = {(W1-W2) / W1} × 100

  Further, the imidization rate of the above self-supporting film can be measured by IR (ATR), and the imidization rate can be calculated using the ratio of the vibration band peak area or height between the film and the fully cured product. it can. As the vibration band peak, a symmetric stretching vibration band of an imidecarbonyl group, a benzene ring skeleton stretching vibration band, or the like is used. Further, regarding the imidization rate measurement, there is also a method using a Karl Fischer moisture meter described in JP-A-9-316199.

  In this invention, you may apply | coat the solution of surface treating agents, such as a coupling agent and a chelating agent, to the single side | surface or both surfaces of the self-supporting film obtained in this way as needed.

  As described above, the self-supporting film produced in the first step is sent to the second step.

<Second step>
In the second step (curing step), the self-supporting film produced in the first step is subjected to heat treatment (thermal curing) to obtain a target polyimide film. At this time, the film may be stretched as necessary.

  The temperature profile of the heat treatment in the second step can be appropriately set according to the physical properties of the target polyimide film.

  An example of the temperature profile of the heat treatment is as follows. The maximum temperature is in the range of 200 to 600 ° C, preferably in the range of 350 to 550 ° C, particularly preferably in the range of 400 to 500 ° C. It is preferable that heating is gradually performed in 0.05 to 5 hours. Preferably the solvent is sufficiently removed from the self-supporting film so that the content of volatile substances composed of an organic solvent and product water in the finally obtained polyimide film is 1% by weight or less, and the film is The imidation of the polymer which comprises is fully performed.

  The heating zone preferably has a temperature gradient, and may be divided into several blocks having different heating temperatures. For example, the primary heat treatment is performed at a relatively low temperature of about 100 to 170 ° C. for about 0.5 to 30 minutes, and then the secondary heating is performed at a temperature of 170 to 220 ° C. for about 0.5 to 30 minutes. Then, a third heat treatment is performed at a high temperature of 220 to 400 ° C. for about 0.5 to 30 minutes, and a fourth high temperature heat treatment is performed at a high temperature of 400 to 600 ° C. if necessary. In another example, primary heat treatment is performed at 80 to 240 ° C., heat treatment is performed at an intermediate heating temperature as necessary, and final heat treatment is performed at 350 to 600 ° C.

  Said heat processing can be performed using well-known various heating apparatuses, such as a hot air furnace and an infrared heating furnace. Heat treatment such as initial heating temperature, intermediate heating temperature, and / or final heating temperature of the film is preferably performed in an inert gas atmosphere such as nitrogen or argon, or a heating gas atmosphere such as air.

  In the heat treatment in the second step (curing step), preferably, a self-supporting film is continuously conveyed in a curing furnace having a predetermined heating zone, for example, by a tenter device, and the width direction is expanded or extended as necessary. By reducing, stretching or relaxation can be performed.

  Any tenter device may be used as long as it can be conveyed while gripping both ends in the width direction of the self-supporting film during the heat treatment, and a piercing pin is used as a film gripping member (pin type tenter) by a clip or a chuck A clip-type tenter, a chuck-type tenter or the like that grips the end of the self-supporting film can be used.

  Since the polyimide film is produced in a long shape by the above production method, in general, a portion obtained by cutting and excluding both ends of the film held in the width direction by the tenter device is wound into a roll shape, and a product roll It is said.

  The thickness of the polyimide film is not particularly limited as long as it is appropriately selected. The thickness is 150 μm or less, preferably 5 to 120 μm, more preferably 6 to 50 μm, still more preferably 7 to 40 μm, and particularly preferably 8. It can be set to ˜35 μm.

  Manufactured by further applying the manufacturing method of the present invention to a polyimide film manufactured only by profile automatic control that automatically adjusts the gap width of the extrusion lip of the T die using the film thickness profile measurement value in the film width direction. The resulting polyimide film is excellent in thickness uniformity in the width direction. Therefore, the product roll of the polyimide film manufactured according to the present invention has less humps, and hence less scratches due to the occurrence of winding slip. And since it is wound up comparatively uniformly, even if it preserve | saves for a long period of time, the extent which becomes polygonal is also small. Moreover, since there is little film thickness nonuniformity, it becomes difficult to generate a high edge.

  Next, the present invention will be further described with reference to examples. In addition, this invention is not limited to a following example.

<Example 1>
A predetermined amount of N, N-dimethylacetamide is added to the polymerization tank, then 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and then paraphenylenediamine are added, and the polymerization reaction is performed at 30 ° C. for 10 hours. A polyimide precursor solution having a polymer logarithmic viscosity (measurement temperature: 30 ° C., concentration: 0.5 g / 100 ml solvent, solvent: N, N-dimethylacetamide) and a polymer concentration of 18% by mass was obtained. In this polyimide precursor solution, a colloidal having an average particle size of 0.08 μm at a ratio of 0.1 part by mass of monostearyl phosphate ester triethanolamine salt and 0.5 part by mass with respect to 100 parts by mass of the polyimide precursor Silica was added and mixed uniformly to obtain a polyimide precursor solution composition. The rotational viscosity of this polyimide precursor solution composition was 3000 poise.

In the first step, the obtained polyimide precursor solution composition was continuously extruded from a T-die onto a smooth metal support in a casting / drying furnace to form a thin film on the support. The thin film was heated at 120 to 160 ° C. for 10 minutes and then peeled off from the support to obtain a self-supporting film. An N, N-dimethylacetamide solution containing a silane coupling agent (N-phenyl-γ-aminopropyltrimethoxysilane) at a concentration of 4% by mass on the B side (support side surface) of this self-supporting film. It apply | coated at 7 g / m < ² >, N, N- dimethylacetamide was apply | coated to the B surface by the application quantity of about 10 g / m < ² >, and it was dried with the hot air of 80-120 degreeC.

  Next, in the second step, both ends of the dry film in the width direction are gripped and inserted into a continuous heating furnace, the film is heated and imidized (maximum temperature of about 500 ° C.), and the average film thickness is 34 μm. Produced a continuous polyimide film having a length of 524 mm.

  In the first step, casting was performed using a T die having an automatic profile control function that automatically adjusts the gap width of the extrusion lip of the T die using the film thickness profile measurement value in the film width direction. In the first step, the gap width of the lip was controlled by adding the following control to the automatic control based on the profile. One bolt is one block, the + period and the-period are 10 minutes each, and the bolt output for periodically adjusting the lip interval is varied by 0.2% (+ control command and -control command). In addition, as shown in the pattern of FIG. 8, the same operation is performed with a delay of 5 minutes between adjacent blocks as it goes to the periphery centering on the central block in the width direction.

  Moreover, 3000 m of the manufactured polyimide film was wound up to make a product roll.

<Comparative Example 1>
When the polyimide precursor solution composition was cast from a T-die, a polyimide film was produced by controlling the lip gap width only by automatic control based on the profile without periodically changing the lip interval.

<Evaluation>
The uniformity of the thickness of the film in the width direction was obtained as a width direction profile of the roll hardness of the 3000 m roll product roll produced in the examples and comparative examples. The roll hardness was measured using “Roll Quality Profiler” manufactured by TAPIO. In this measurement, the hardness value increases as the winding becomes harder, and the hardness value appears smaller as the winding becomes looser. The thickness unevenness was evaluated from the difference between the maximum hardness and the minimum hardness in the width direction.

  From Table 1, it can be seen that the thickness unevenness is reduced by the method of the present invention.

  The present invention is useful for producing a long film wound on a roll.

10 T die 12 Upper lip 11 Lower lip 13 Bolt 20 Extruded film

Claims (8)

A film manufacturing method having at least one step of continuously extruding a film raw material from a T-die capable of adjusting a lip interval,
When the width direction of the T die is divided into m fine adjustable blocks,
For a given block (k), a control command to alternately increase a lip interval by ΔT and a control command to narrow the lip interval by ΔT with a predetermined period is performed.
Control is performed so that the block (k + 1) adjacent to the arbitrary block (k) performs the same operation as the arbitrary block (k) with a delay of a predetermined period (however, m and k It is a positive integer, 1 ≦ k <meets m, and the predetermined time period between adjacent blocks delay, control command and the next + - to control instruction time and - control command and the next + (It is shorter than the time to control command. )
The film manufacturing method characterized by these. A film manufacturing method having at least one step of continuously extruding a film raw material from a T-die capable of adjusting a lip interval,
When the width direction of the T die is divided into m fine adjustable blocks,
For a specific block (k ₀ ) among the m blocks, a + control command that widens the lip interval by ΔT and a −control command that narrows the lip interval by ΔT alternately with a predetermined period. Control to
In k ₀ from the number of large blocks _(k 0 + i), from adjacent blocks _{(k 0 + i-1)} , delayed by a predetermined time, it performs the same operation as the block _{(k 0),}
In k ₀ of from numbers less block _(k 0 -j), from adjacent blocks _(k 0 -j + 1), delayed by a predetermined time, to perform the same operation as the block _{(k 0)} (where, _{k 0} , I, j are positive integers, m is as defined in claim 1, and each parameter has the following relationship:
1 <k ₀ <m
1 ≦ (k ₀ −j) <k ₀ <(k ₀ + i) ≦ m
Meet. )
The film manufacturing method characterized by these. Delay of a predetermined time period between adjacent blocks, the control command and the next + - time to control command and - according to claim 2, characterized in that shorter than the time until the control command and the next + control command Film manufacturing method. The delay of a predetermined period between adjacent blocks is less than half of the time between the + control command and the next -control command and the time between the -control command and the next + control command. The film manufacturing method of Claim 1 or 3 . The T die capable of adjusting the lip interval is a T die having a profile automatic control function that automatically adjusts the gap width of the extrusion lip of the T die using a film thickness profile measurement value in the film width direction. The film manufacturing method according to any one of claims 1 to 4 . 6. The film manufacturing method according to claim 1, wherein the time between the + control command and the next -control command is equal and periodic.   The said film raw material is a solution containing a solvent, Comprising: At least one part of the said solvent is evaporated and removed from the solution film extruded from the said T-die. Film manufacturing method. The film to be manufactured is a polyimide film,
The film raw material is a polyimide precursor solution,
The film manufacturing method according to claim 1, further comprising a step of casting the polyimide precursor solution on a support from the T die.

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