TWI565736B - Method for producing polyimide film - Google Patents

Description

Method for producing polyimine film

The present invention relates to a method for producing a polyimide film.

It is known that a polyimine obtained by imidating a polyimine precursor such as polyacrylic acid is known. The film made of the polyimine is a material excellent in strength, heat resistance, and insulation, and is widely used in industrial products such as a flexible printed circuit board or a semiconductor protective film. In the method for producing a polyimide film, it is known that imidization of ruthenium by a dehydration reaction by heating polylysine at 300 to 500 °C. For example, Patent Document 1 discloses that polyacrylamide is subjected to ruthenium imidization in a far-infrared furnace at 300 ° C to obtain a polyimide film.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-321300

However, in order to shorten the process time, the production method of such a polyimide may be expected to further increase the reaction rate of the dehydration reaction.

The present invention has been completed to solve such problems, and the main purpose is to Providing: When manufacturing a polyimide film, the reaction speed of the dehydration reaction can be further enhanced.

In order to achieve the above object, the inventors have found that in the step of forming a polyimine by using a dehydration reaction, the polyimine precursor can be efficiently dehydrated by irradiating near infrared rays. invention.

That is, the method for producing the polyimide film of the present invention includes: (a) a step of applying a film precursor containing a polyimide precursor which is a polyimine imide by dehydration to a sheet; and (b) irradiating the film precursor with near-infrared rays, The polyimine precursor is dehydrated to form the film precursor into a polyimide film.

The method for producing the polyimine film of the present invention will first contain If dehydrated, it will become a film precursor of the polyimide precursor of polyimine, which is applied to the sheet. Next, the polyimide precursor is dehydrated by irradiating the film precursor with near-infrared rays to make the film precursor a polyimine film. Thereby, the reaction rate of the dehydration reaction can be increased as compared with the case where the near infrared ray is not used. Further, the reason why the reaction rate is increased is considered to be that energy can be selectively applied to the reaction group (imine group, hydroxyl group, or the like) of the dehydration reaction by irradiation of near-infrared rays. The near infrared ray is, for example, an electromagnetic wave having a wavelength of 0.7 to 3.5 μm. In this case, in the above step (b), it is preferred to irradiate near-infrared rays having a wavelength of 2.5 to 3.5 μm, and more preferably to irradiate near-infrared rays having a wavelength of 2.9 to 3.3 μm. In this case, the energy of the reaction group of the dehydration reaction can be more selectively input. In addition, after the above step (a), the film precursor may be dried before the step (b) A step of.

The method for producing a polyimide film of the present invention, in the above step (b) Drying of the film precursor and dehydration of the polyimine precursor described above may also be performed by irradiating the film precursor with near infrared rays. In this case, since near-infrared rays can efficiently cut off hydrogen bonds, not only dehydration but also drying can be performed efficiently.

The method for producing a polyimide film of the present invention, in the above step (b) The above-mentioned film precursor may also be subjected to near-infrared irradiation and hot air blowing. According to this, the removal of moisture due to the dehydration reaction of the polyimide precursor can be performed more efficiently.

10‧‧‧Reaction furnace

14‧‧‧ furnace body

15‧‧‧ front end

16‧‧‧ rear end face

17, 18‧‧‧ openings

19‧‧‧Transportation path

20, 20a, 20b‧‧‧air supply device

22, 22a, 22b‧‧‧ hot air generator

24, 24a, 24b‧‧‧pipe structure

26, 26a, 26b‧‧ vents

30‧‧‧Infrared heater

32‧‧‧The original silk

34‧‧‧Electrical wiring

36‧‧‧Inside

37‧‧‧Temperature Sensor

38‧‧‧ heater body

40‧‧‧External management

42‧‧‧Cap

44‧‧‧Wiring pull out

46‧‧‧ Fluid inlet and outlet

48‧‧‧Flow

49‧‧‧Support frame

50‧‧‧Sheet

52‧‧·coating film

54, 56‧‧‧ Roll

60‧‧‧ Controller

70‧‧‧Cooling fluid supply

72‧‧‧Opening and closing valve

74‧‧‧Flow adjustment valve

80‧‧‧Power supply source

90‧‧‧Exhaust device

92‧‧‧ Hair dryer

94‧‧‧pipe structure

96‧‧‧Exhaust port

1 is a longitudinal sectional view of a reaction furnace 10.

2 is a longitudinal sectional view of the infrared heater 30.

Figure 3 is a cross-sectional view taken along line A-A of Figure 2;

Fig. 4 is a longitudinal sectional view showing a reactor 10 of a modification.

Next, an embodiment of the present invention will be described using a schematic diagram. Fig. 1 is a longitudinal sectional view showing a reaction furnace 10 used in a method for producing a polyimide film of the present invention. In the reaction furnace 10, a coating film 52 containing a polyimide precursor is applied to the sheet 50, and a near-infrared ray and a hot air blower are provided, and the furnace body 14, the conveyance path 19, the air blowing device 20, and infrared heating are provided. The controller 30 and the controller 60.

The furnace body 14 is formed into a slightly cubic heat insulating structure at the front end surface. The opening 15 and the rear end face 16 are respectively provided with openings 17, 18. The length of the furnace body 14 from the front end surface 15 to the rear end surface 16 is, for example, 2 to 10 m.

The conveying passage 19 is a passage from the opening 17 to the opening 18, facing the water The furnace body 14 is penetrated in the flat direction. The sheet 50 on which the coating film 52 has been applied on one side passes through the conveyance path 19. The sheet 50 is placed with the surface of the applied coating film 52 facing upward, carried in from the opening 17, and advanced in the horizontal direction inside the furnace body 14, and then carried out from the opening 18.

The air blowing device 20 is a device that heats and dries the coating film 52 that passes through the reaction furnace 10 (furnace body 14) by blowing hot air. The air blowing device 20 includes a blowing device 20a disposed on the upper side of the furnace body 14, and a blowing device 20b disposed on the lower side of the furnace body 14. The air blowing devices 20a and 20b are respectively provided with hot air generators 22a and 22b, pipe structure bodies 24a and 24b, and vent ports 26a and 26b. Hereinafter, description will be made using the air blowing device 20a. The air blowing device 20a is provided with a hot air generator 22a, a duct structure 24a, and a vent port 26a. The hot air generator 22a is attached to the pipe structure 24a, and supplies hot air to the inside of the pipe structure 24a. Hot air is for example heating the air. The hot air generator 22a is capable of adjusting the amount of wind and temperature at which hot air is generated. Hot wind is not particularly limited, and may be adjusted within e.g. ^{100Nm 3 / h ~ 2000Nm 3 /} h range. The temperature of the hot air is not particularly limited and can be adjusted, for example, in the range of 40 to 400 °C. The pipe structure 24a is a passage for hot air from the hot air generator 22a, and has a plurality of passages that branch from the hot air generator 22a into the furnace body 14. The pipe structure 24a penetrates the top plate of the furnace body 14 at the passage portion of the branch, and the branch passage is directed downward. The lower end of the branch passage is a vent 26a, and the vent 26a is also directed downward. In the present embodiment, the pipe structure 24a is provided with 14 branches, and the vents 26a are also formed to be 14 pieces. As a result, the hot air from the hot air generator 22a of the air blowing device 20a is blown from the 14 vent holes 26a in the vertical direction, and is vertically in contact with the surface of the coating film 52. Further, the vent hole 26a has a slightly uniform design from the side of the front end surface 15 to the side of the rear end surface 16. The hot air generator 22b, the duct structure 24b, and the vent port 26b of the related air blowing device 20b are also configured similarly to the hot air generator 22a, the duct structure 24a, and the vent port 26a. However, the air blowing device 20b is configured to be upside down with the air blowing device 20a in Fig. 1 so as to generate hot air in the vertical direction. In other words, the hot air from the hot air generator 22b is blown upward from the vent hole 26b in the vertical direction, and vertically abuts against the back surface of the sheet 50 (the surface on the back side of the surface on which the coating film 52 is formed). Further, by blowing the hot air from the upper and lower sides of the sheet 50 by the hot air generators 22a and 22b, it is possible to suppress the deformation of the sheet 50 and the coating film 52 caused by the hot air.

The infrared heater 30 is a device that irradiates the coating film 52 in the reaction furnace 10 (the furnace body 14) with near-infrared rays, and is mounted in plural to the top plate of the furnace body 14. In the present embodiment, the infrared heaters 30 are arranged slightly evenly from the front end surface 15 side to the rear end surface 16 side. Each of the infrared heaters 30 has the same structure, and is mounted in a state in which the longitudinal direction is orthogonal to the transport direction.

2 is a longitudinal sectional view of the infrared heater 30, and FIG. 3 is a cross-sectional view taken along line A-A of FIG. As shown in FIG. 2 and FIG. 3, the infrared heater 30 includes a heater main body 38 that surrounds the inner tube 36, and an outer tube 40 that surrounds the heater main body 38, and is hermetically embedded. A bottomed cylindrical cap 42 at both ends of the outer tube 40, a flow path 48 formed between the heater body 38 and the outer tube 40 to allow a cooling fluid to flow, and a temperature sensor 37 for detecting the surface temperature of the outer tube 40. The raw wire 32 is supplied with electric power from the power supply source 80, and is heated by electricity. For example, at 700 to 1500 ° C, infrared rays having a peak at a wavelength of about 3 μm and containing a wavelength component of 2.5 μm to 3.5 μm are emitted. The electric wiring 34 to which the raw yarn 32 is connected is airtightly pulled out to the outside via the wiring pull-out portion 44 provided in the cap 42 and is connected to the electric power supply source 80. The inner tube 36 is made of quartz glass, bismuth borosilicate glass or the like, and has a filter function of infrared rays having a wavelength of 3.5 μm or less but absorbing infrared rays having a wavelength of more than 3.5 μm. The heater body 38 has two ends supported by a support frame 49 disposed inside the cap body 42. The outer tube 40 is made of quartz glass, barium borosilicate glass or the like similar to the inner tube 36, and has a filter function of infrared rays having a wavelength of 3.5 μm or less but absorbing infrared rays having a wavelength of more than 3.5 μm. Each cap 42 has a fluid inlet and outlet 46. The flow path 48 is a state in which the cooling fluid supplied from the cooling fluid supply source 70 flows from one of the fluid inlets and outlets 46 toward the other fluid inlet and outlet 46. The cooling flow system (for example, air, inert gas, or the like) flowing through the flow path 48 cools each of the tubes 36 and 40 by contacting the inner tube 36 and the outer tube 40 to take heat. In the infrared heater 30, infrared rays having a peak at a wavelength of about 3 μm are emitted from the raw yarn 32, and infrared rays having a wavelength of 3.5 μm or less pass through the inner tube 36 and the outer tube 40, and are irradiated onto the sheet 50 passing through the conveyance path. Coating film 52. The infrared ray of this wavelength is excellent in the ability to cut a solvent hydrogen bond contained in the coating film 52 of the sheet 50, and can evaporate a solvent efficiently. On the other hand, although the inner tube 36 and the outer tube 40 absorb infrared rays having a wavelength of more than 3.5 μm, they are cooled by the cooling fluid flowing in the flow path 48, so that the solvent evaporated from the coating film 52 can be maintained. The temperature of the ignition point (for example, below 200 ° C).

The controller 60 constitutes a CPU-centric microprocessor. The controller 60 outputs a control letter to the hot air generators 22a and 22b of the air blowing device 20. The temperature and the amount of hot air generated by the hot air generators 22a, 22b are individually controlled. Further, the controller 60 outputs the temperature of the outer tube 40 of the temperature sensor 37 detected by the temperature sensor 37 belonging to the thermocouple, or the piping connecting the cooling fluid supply source 70 and the fluid inlet and outlet 46. The on-off valve 72 and the flow rate adjustment valve 74 provided on the way output control signals, and individually control the flow rate of the cooling fluid flowing in the flow path 48 of the infrared heater 30. Further, the controller 60 outputs a control signal for adjusting the power supplied from the power supply source 80 to the original wire 32, and outputs it to the power supply source 80, and individually controls the temperature of the original wire of the infrared heater 30. Further, the controller 60 can adjust the passage time of the coating film 52 in the furnace body 14 by controlling the rotational speed of the rollers 54, 56.

Secondly, it is directed to the use of the polyimine of the reaction furnace 10 constructed accordingly. A method of producing a film will be described. The method for producing the polyimide film comprises: (a) coating a film precursor (coating film 52) containing a polyimide precursor which becomes a polyimine by dehydration, and applying it to a sheet. (b) a step of drying the coating film 52 by applying the near-infrared ray irradiation and the hot air blowing to the coating film 52, and dehydrating the polyimine precursor to form the coating film 52 into a polyimide film. .

In the step (a), first, the roller disposed from the left end of the reaction furnace 10 The stripping sheet 50 is wound up on the sheet 54, and the coating film 52 is applied thereon by a coater just before being carried into the reactor 10 (furnace body 14), and then passed through the opening 17 of the reactor 10 and carried into the reactor 10.

Here, the sheet 50 is not particularly limited and may be, for example, aluminum, copper, or the like. Metal sheets. Further, the coating film 52 is applied to the sheet 50 by a polyimide precursor which is a polyimide precursor which is polyimine when dehydrated and which is kneaded with a solvent. The above. The polyimine precursor is not particularly limited as long as it can be polyimine by dehydration, and may be a single material or a mixture of two or more materials. Specific examples of the polyimine precursor may be, for example, a polyamic acid represented by the following chemical formula (1). In the following chemical formula (1), R is a 4-membered organic group, and R' is a 2-membered organic group. Further, at least one of R and R' may be aromatic.

The polyaminic acid represented by the above chemical formula (1) is, for example, at least one acid The dianhydride and at least one diamine can be produced by polymerization using a known method. The acid dianhydride may be, for example, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 1, 2,5,6-naphthalenetetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic acid Anhydride, 3,3',4,4'-dioxalic acid dianhydride, p-phenylene bis(trimellitic acid monoester anhydride), 4,4'-biphenylbis(trimellitic acid mono An ester anhydride), and the like (derivatives) and the like. Among these, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, p - phenyl bis(trimellitic acid monoester anhydride), 4,4'-biphenyl bis(trimellitic acid monoester anhydride). These acid dianhydrides may be used alone or in combination of two or more kinds in any ratio.

The diamine system can be, for example, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenylsulfide. Ether, 4,4'-diamino Diphenyl hydrazine, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 1,4-diaminobenzene (p-phenylenediamine), 1,3-diamine Benzene, 1,2-diaminobenzene, 4,4'-diaminobenzimidamide, 3,4'-diaminobenzimidamide, and the like (derivatives) and the like. Among these, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 3,3'-dichlorobenzidine, 4,4'-diaminobenzene are preferred. Toluene aniline, 4,4'-diaminodiphenyl ether, p-phenylenediamine, more preferably 4,4'-diaminobenzimidil. These diamines may be used alone or in combination of two or more kinds in any ratio.

In the present embodiment, the polyimine precursor is a polyamic acid represented by the following chemical formula (2). The polyamic acid is produced, for example, from the above tetracarboxylic dianhydride and a diamine by a known method.

The solvent contained in the coating film 52 can be, for example, N-methyl-2-pyrrolidine. Ketone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), and the like. The thickness of the coating film 52 is not particularly limited and may be, for example, 10 to 400 μm. The coating film 52 may further contain a dehydrating agent (chemical conversion agent), a ruthenium imidating agent (catalyst), or the like in addition to the polyimine precursor and the solvent. The dehydrating agent may be, for example, an aliphatic acid anhydride, an aromatic acid anhydride, an N,N'-dialkylcarbodiimide, a lower aliphatic halide, a halogenated lower fatty acid anhydride, an arylphosphonic acid dihalide, a sulfinium sulfonate. Base halides, etc. These may be used alone or in combination of two or more. Among the above dehydrating agents, aliphatic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride are preferred, and a mixture of such compounds. The quinone imidization agent may be, for example, an aliphatic tertiary amine, an aromatic tertiary amine, or a heterocyclic tertiary amine. These may be used alone or in combination of two or more. Among the above quinone imidization agents, a heterocyclic tertiary amine such as isoquinoline, β-picoline or pyridine is preferred.

Next, in step (b), the sheet 50 passes through the furnace body 14. at this time, The coating film 52 is heated to, for example, 350 ° C by hot air blown from the air blowing device 20 and infrared rays irradiated from the infrared heater 30, and the polyamine acid in the coating film 52 is subjected to dehydration cyclization reaction to carry out quinone imine. Chemical. Thus, the polyaminic acid represented by the above chemical formula (1) is a polyimine represented by the following chemical formula (3) [in the present embodiment, the following chemical formula (4)], and the coating film 52 is made into a polyfluorene. Amine film. In addition, the solvent evaporated from the coating film 52 and the water vapor generated by the dehydration are discharged to the outside by, for example, a blower from a discharge port (not shown). The coating film 52 is finally carried out from the opening 18 of the reaction furnace 10, and is taken up together with the sheet 50 on the roller 56 provided at the right end of the reaction furnace 10. Further, the thickness of the produced polyimide film is not particularly limited, and may be, for example, 3 to 200 μm.

According to the method for producing a polyimide film according to the above steps (a) and (b), the reaction rate of the dehydration cyclization reaction of the polylysine can be further enhanced. The reason can be considered as follows. The infrared heater 30 of the reaction furnace 10 irradiates the coating film 52 of the sheet 50 with infrared rays having a wavelength of 3.5 μm or less as described above. Therefore, the coating film 52 is irradiated with near-infrared rays in a wavelength region of 0.7 to 3.5 μm, particularly near-infrared rays in a wavelength region of 2.5 μm to 3.5 μm. Here, the reaction group of the dehydration cyclization reaction of polyproline is an imine group and a hydroxyl group, and the absorption spectrum of the imine group is 3450 to 3300 cm ^-1 (= 2.9 to 3.0 μm), and the absorption spectrum of the hydroxyl group is about 3000 cm. ^-1 (= approx. 3.3μm). By irradiating near-infrared rays having a wavelength close to the absorption spectrum of 2.5 μm to 3.5 μm, energy can be selectively applied to the reactive groups of the dehydration cyclization reaction, so that the reaction of the dehydration cyclization reaction of poly-proline can be improved. speed. Further, it is more preferable that the near-infrared rays from the infrared heater 30 contain electromagnetic waves having a wavelength of 2.9 to 3.3 μm from the absorption spectrum of the imine group and the hydroxyl group. Further, in the method for producing a polyimide film by the above steps (a) and (b), since the near-infrared selective can be used to input energy to the reactive group of the dehydration cyclization reaction, the conventional polyimide film is compared with the conventional polyimide film. In the production method, when the dehydration cyclization reaction is carried out without using near-infrared rays (for example, only by hot air blowing), the dehydration cyclization reaction of polyglycine can be produced even at a relatively low temperature (for example, less than 300 ° C). Therefore, for example, deformation of the polyimide film caused by heat shrinkage of the sheet 50 and the coating film 52 can be further suppressed. By suppressing the deformation of the polyimide film, it is possible to suppress, for example, a pattern shift or a damage of the substrate caused by a circuit mounted on the polyimide film.

As described above, in the method for producing a polyimide film of the present embodiment, the step (a) contains a polyimine which becomes a polyimine if it is dehydrated. The film precursor of the precursor (coating film 52) is applied to the sheet. Next, in the step (b), the polyimide film precursor is dehydrated by irradiating the coating film 52 with near-infrared rays to form the coating film 52 as a polyimide film. Thereby, the reaction rate of the dehydration reaction can be increased as compared with the case where the near infrared ray is not used. Further, in the step (b), since the near-infrared rays having a wavelength of 2.5 to 3.5 μm are irradiated, the reaction rate of the dehydration reaction can be more surely improved. Further, in the step (b), since the coating film 52 is irradiated with near-infrared rays to dry the coating film 52 and dehydrate the polyimide precursor, the coating film 52 can be dried even if it is dehydrated. Execute efficiently. Further, in the step (b), since the near-infrared ray irradiation and the hot air blowing are applied to the coating film 52, the removal of moisture due to evaporation of the solvent and the dehydration reaction of the polyimide precursor can be more efficiently performed.

Further, the present invention is not limited to the above-described embodiments, and may be embodied in various aspects without departing from the technical scope of the present invention.

For example, in the above embodiment, the reaction group is an imine group and a hydroxyl group in the dehydration reaction of the polyimine precursor, but the absorption spectrum is included in the near-infrared wavelength region (0.7 to 3.5 μm). Under the premise, it is not limited to these.

In the above embodiment, the air blowing device 20 and the infrared heater 30 are provided in the reaction furnace 10. However, the polyimide film precursor of the coating film 52 can be dehydrated by using near infrared rays, and the air blowing device 20b may not be provided. Also, none of the air blowing devices 20a, 20b are provided. Alternatively, the air blowing device may have other configurations. For example, the vents 26a, 26b of the air blowing devices 20a, 20b may not be equally spaced. Alternatively, the air blowing means is configured to blow hot air from one end of the furnace body 14 toward the other end (for example, from the rear end portion 16 toward the front end portion 15). For example, Figure 4 In the air blowing device 20, a vent opening 26 that opens toward the front end portion 15 and opens in the horizontal direction may be provided in the vicinity of the rear end portion 16 in the furnace body 14, and hot air from the hot air generator 22 provided outside the furnace body 14 may be passed through The duct structure 24 blows air from the vent 26 in the horizontal direction. In this case, as shown in FIG. 4, an exhaust device 90 for exhausting hot air from the vent port 26 and heating the coating film 52 may be provided. The exhaust device 90 is provided with an exhaust port 96 that opens toward the rear end portion 16 in the vicinity of the front end portion 15 in the furnace body 14 and that opens in the horizontal direction, a blower 92 provided outside the furnace body 14, and a blower 92 A pipe structure connected to the exhaust port 96.

The infrared heater 30 of the above embodiment is capable of being irradiated The electromagnetic wave having a near-infrared wavelength may be used, and for example, a filter capable of absorbing electromagnetic waves having a wavelength of less than 2.5 μm may be further provided. In this case, the near-infrared rays having a wavelength of 2.5 μm to 3.5 μm can be more efficiently irradiated onto the coating film 52. Further, the inner tube 36 and the outer tube 40 may be formed so as not to absorb infrared rays exceeding 3.5 μm, and the coating film 52 can be irradiated even if infrared rays having a wavelength exceeding 3.5 μm.

In the above embodiment, the coating is applied to one side (upper surface) of the sheet 50. Membrane 52, but not limited to this. For example, the coating film 52 may be applied to both sides (upper and lower surfaces) of the sheet 50, respectively.

In the above embodiment, the coating film 52 passes through the furnace body of the reaction furnace 10. The drying and dehydration of the coating film 52 are carried out together during the period of 14, but it is not limited thereto. For example, the coating film 52 may be subjected to a drying step, and then the coating film 52 may be dehydrated in the furnace body 14. The drying step in this case may be carried out by at least one of hot air blowing and infrared irradiation, or may be performed by, for example, passing the coating film 52 through a drying furnace having the same configuration as that of the reaction furnace 10. In addition, even if the drying step is performed first, it can be performed in the furnace body 14 together. Dewatering and drying of the coating film 52.

In the above embodiment, the reaction furnace 10 is provided with one furnace body 14, However, a plurality of furnace bodies 14 can also be provided. For example, the furnace body 14 provided with the air blowing device 20 and the infrared heater 30 may be set to one unit, and the reaction furnace 10 may be provided with a plurality of units, and the coating film 52 may sequentially pass through the plurality of units (the furnace body 14). internal. In this case, the dehydration of the coating film 52 may be carried out in at least one of the plurality of units. The plurality of units may also include a unit that performs a drying step before dehydration, and a unit that performs dehydration.

In the above embodiment, a plurality of the transport paths 19 may be provided. The support roller of the sheet 50 is supported from below. According to this, it is possible to prevent the sheet 50 from being bent due to gravity.

In the above embodiment, the infrared heater 30 is used in the original yarn. The outer circumference of 32 is concentrically coated by a plurality of tubes 36 and 40 having a filter function of absorbing infrared rays having a wavelength of more than 3.5 μm, and a surface capable of suppressing the infrared heater 30 is formed between the plurality of tubes 36 and 40. The cooling fluid flow path 48 for temperature rise is used, but other infrared heaters may be used.

In the above embodiment, the ambient gas system of each reaction furnace 10 is used. Air, but it can also replace the air, instead use an inert gas such as nitrogen.

This application is the date of the application filed on October 11, 2012. The patent application No. 2012-225818 is the basis of the priority claim, the contents of which are incorporated herein by reference.

Industrial availability

The present invention can be utilized in a manufacturing industry in which a polyimine precursor such as polylysine is subjected to ruthenium imidization to obtain a polyimine. It is used in a manufacturing industry such as a flexible printed circuit board or a semiconductor including a protective film made of a film using the polyimide.

10‧‧‧Reaction furnace

14‧‧‧ furnace body

15‧‧‧ front end

16‧‧‧ rear end face

17, 18‧‧‧ openings

19‧‧‧Transportation path

20‧‧‧Air supply device

20a‧‧‧Air supply unit

22a, 22b‧‧‧ hot air generator

24a, 24b‧‧‧pipe structure

50‧‧‧Sheet

52‧‧·coating film

54, 56‧‧‧ Roll

60‧‧‧ Controller

Claims (6)

A method for producing a polyimide film comprising: (a) a step of coating a film precursor containing a polyimide precursor which is a polyimine imide by dehydration, onto a sheet; and (b) The step of dehydrating the polyimine precursor by irradiating the film precursor with near-infrared rays to form the film precursor into a polyimide film. The method for producing a polyimide film according to the first aspect of the invention, wherein the step (b) is irradiating a near-infrared ray having a wavelength of 2.5 to 3.5 μm. The method for producing a polyimide film according to claim 1 or 2, wherein in the step (b), the film precursor is dried by the near-infrared rays, and the film precursor is dried and aggregated. Dehydration of the quinone imine precursor. The method for producing a polyimide film according to claim 1 or 2, wherein in the step (b), the film precursor is subjected to near-infrared irradiation and hot air blowing. The method for producing a polyimide film according to claim 1 or 2, wherein the polyimine precursor is a polyamic acid represented by the chemical formula (1): In the chemical formula (1), R is a 4-membered organic group, and R' is a 2-membered organic group. The method for producing a polyimide film according to claim 1 or 2, wherein the polyimine precursor is a polyamic acid represented by the chemical formula (2):