Resin film manufacturing method and pre-cut film

Abstract

Provided is a method of producing a resin film that enables more effective suppression of tearing of the film when two ends of the film are being gripped by a tenter transportation device.　The method of producing a resin film is characterized by comprising: a step A for coating a middle part of a support body with a first resin composition solution; a step B for coating two ends adjacent to the middle part with a second resin composition solution; a step C for drying the first resin composition solution and the second resin composition solution to obtain an uncut film; a step D for peeling the uncut film off of the support body; a step E, after the step D, for gripping two ends of the uncut film with a tenter transportation device; a step F for transporting the uncut film in the state where the two ends of the uncut film are being gripped; and a step G, which follows the step F, for removing a portion, formed from the second resin composition solution, from the uncut film to obtain a resin film. The method of producing a resin film is also characterized in that: the first resin composition solution contains a first resin and a filler; the amount of filler contained is 0.1 to 50 mass% with respect to the first resin; the second resin composition solution contains a second resin, and either does not contain any filler, or does contain the foregoing but less than the amount contained of the first resin composition solution and at 2 mass% or less with respect to the second resin; and the uncut film after the step C and before the step F has a tear strength at the portion formed from the second resin composition solution that is greater than the tear strength at a portion formed from the first resin composition solution.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a resin film and a pre-cut film. [Background technology]

[0002] Conventionally, in the film manufacturing process, a tenter-type conveying device has been known in which, when the film is conveyed, dried, heat-treated, etc., both ends of the film in the width direction are gripped with a number of pins or clips, thereby applying tension to the film in the width direction while the film is conveyed (see, for example, Patent Document 1).

[0003] There are several conveying methods for tenter-type conveying devices. Among these conveying methods, pin tenter-type conveying devices, which grip a film by piercing both ends of the film with multiple pins along the film flow direction, have multiple pins arranged on a pin seat supported by a pair of moving chains arranged parallel to each other. This pin tenter-type conveying device has issues such as the holes formed in the film by the pin piercings tearing into elongated holes in the film's width direction when the film's shrinkage force (tensile force) increases. If the holes tear, the film cannot maintain its proper tension, resulting in wrinkles and other degradation in quality. Consequently, the tearing of the holes causes production losses and reduces production efficiency. Furthermore, even when using clip tenter-type conveying devices that grip both ends with clips, the same issues as when using pin tenter-type conveying devices, such as film tearing at the clip-held portions, remain.

[0004] Resin films characterized by a low coefficient of linear thermal expansion (CTE), which has become increasingly popular in recent years, tend to have low tear strength because their molecular chains are rigid, making them less likely to entangle with each other and more brittle. A particularly strong demand for low CTE exists in glass replacement applications such as display substrate materials. However, since it is difficult to meet the required physical properties using resin materials alone, the introduction of fillers such as silica has been proposed (see Patent Document 2). Resin films containing such fillers have even lower tear strength, making the problem of tearing at the supported area even more pronounced.

[0005] To solve this problem, it has been proposed to overlap a film with high tear strength as a reinforcing film on the gripping portion (edge) of a film with low tear strength (see Patent Document 3).It has also been proposed that when conveying a sheet or the like, the pin arrangement density at both ends of the sheet be made higher on the inner side in the width direction than on the outer side (see Patent Document 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 39-29211 [Patent Document 2] WO2013 / 161970 publication [Patent Document 3] Japanese Patent Application Publication No. 11-254521 [Patent Document 4] Japanese Patent Application Publication No. 9-77315 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the method of Patent Document 3 involves overlaying a film with low tear strength on a film with high tear strength, which results in a problem of wasting a lot of raw material. That is, the gripping portion is a portion that will eventually be slit and discarded after transportation, and if this gripping portion has a two-layer structure, there is a problem that a large portion will be discarded. Furthermore, the method of Patent Document 4 cannot be used with resin films containing fillers with even lower tear strength, resin films characterized by low CTE, etc., and there is a problem that holes formed in the film may tear when pierced with a pin.

[0008] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a method for manufacturing a resin film and a pre-cut film that can more effectively prevent film tearing when both ends of the film are gripped by a tenter-type conveying device. [Means for solving the problem]

[0009] The present inventors have conducted extensive research into a method for producing a resin film characterized by exhibiting a low CTE, and into a pre-cut film. As a result, they have found that by employing the following configuration, tearing of the film can be more effectively suppressed when both ends of the film are gripped by a tenter-type conveying device, and have completed the present invention.

[0010] That is, the method for producing a resin film according to the present invention is as follows: A step A of applying a first resin composition solution to the center of a support; Step B: applying a second resin composition solution to both end portions adjacent to the central portion; a step C of drying the first resin composition solution and the second resin composition solution to obtain a pre-cut film; Step D: peeling the pre-cut film from the support; a step E of holding both ends of the pre-cut film by a tenter-type conveying device after the step D; a step F of conveying the pre-cut film while holding both end portions of the pre-cut film; and After the step F, a step G is performed in which the portion formed from the second resin composition solution is removed from the pre-cut film to obtain a resin film. and the first resin composition solution contains a first resin and a filler, and the content of the filler is 0.1% by mass or more and 50% by mass or less with respect to the first resin; the second resin composition solution contains a second resin and does not contain a filler, or if it contains a filler, the content of the filler is less than that of the first resin composition solution and is 2 mass % or less relative to the second resin; After step C and before step F, the pre-cut film is characterized in that the tear strength of the portion formed from the second resin composition solution is greater than the tear strength of the portion formed from the first resin composition solution.

[0011] According to the above configuration, a first resin composition solution is applied to the center of a support (step A), a second resin composition solution is applied to both end portions (step B), and the first and second resin composition solutions are dried to obtain a pre-cut film (step C). Both end portions of the pre-cut film thus obtained are formed solely from the second resin composition solution. Here, the tear strength of the portion formed solely from the second resin composition solution is greater than the tear strength of the portion formed from the first resin composition solution. Therefore, even if the pre-cut film is transported while both end portions are gripped by a tenter-type transport device (step F), tearing is unlikely to occur at the gripped portions (both end portions). Furthermore, according to the above configuration, after step F, the portion formed from the second resin composition solution is removed from the pre-cut film to obtain a resin film (step G). According to this method, even a resin film with low tear strength can be transported using a conventionally known tenter-type transport device. Furthermore, because both end portions of the pre-cut film are formed only from the second resin composition solution, it is possible to minimize waste of raw materials related to the portions removed in step G.

[0012] The resin film obtained in the step G preferably has a CTE of 5 ppm / K or more and 50 ppm / K or less. According to the above-mentioned configuration, the resin film has excellent heat resistance because the CTE is within a predetermined range.

[0013] In the above-described configuration, the step E is preferably a step of gripping both end portions of the uncut film with pins of a pin tenter type conveying device.

[0014] Since the tear strength of the portion of the pre-cut film formed from the first resin composition solution is greater than the tear strength of the portion formed from the second resin composition solution, tearing caused by the pins of a pin tenter-type conveying device is more effectively prevented.

[0015] The present invention can be applied to all resin films that can be solution-formed. Solution film formation can be applied to all resins in which the resin or a resin precursor is soluble in a solvent, but from an industrial standpoint, it is preferably applied to resins that are difficult to form into a film by melting, such as cellulose triacetate, aromatic polyamide, polyimide, polyetherimide, polyamideimide, polyesterimide, polybenzoxazole, polybenzimidazole, and polybenzothiazole. Of these, polyimide-based resins such as polyimide, polyamideimide, polyetherimide, and polyimidebenzoxazole are particularly preferably applied.

[0016] In the above-mentioned configuration, the support is preferably a polymer film.

[0017] In the above-described configuration, the filler is preferably silica.

[0018] In recent years, there has been a high demand for colorless, transparent, and low CTE polyimide-based resin films, but such polyimide-based resin films tend to have low tear strength. Furthermore, the introduction of fillers has been considered to achieve both transparency and a low CTE, which further reduces tear strength. Therefore, the above-described configuration makes it possible to suitably obtain polyimide-based resin films with particularly low tear strength.

[0019] Further, the pre-cut film according to the present invention is The center and and both end portions formed continuously from the central portion at both ends of the central portion. and the central portion is made of a first resin composition containing a first resin and a filler, and the content of the filler is 0.1% by mass or more and 50% by mass or less with respect to the first resin; the two end portions are made of a second resin composition containing a second resin, and the second resin composition does not contain a filler, or even if it contains a filler, the content of the filler is less than that of the first resin composition and is 2 mass % or less relative to the second resin; The tear strength at both ends is greater than the tear strength at the center.

[0020] According to the above configuration, the tear strength of both ends is greater than the tear strength of the central portion, so even if the pre-cut film is transported while both ends are gripped by a tenter-type transport device, tearing is unlikely to occur at the gripped portions (both ends). Furthermore, since both ends of the film before cutting are composed only of the second resin composition, when removing both ends to obtain the resin film, it is possible to minimize waste of raw materials from the removed parts.

[0021] In the above-described configuration, the first resin is preferably a polyimide resin.

[0022] When the first resin is a polyimide resin, a polyimide resin film having low tear strength can be suitably obtained by removing both end portions after transporting the film using a tenter-type transport device.

[0023] The CTE of the central portion is preferably 5 ppm / K or more and 50 ppm / K or less. According to the above configuration, by removing both end portions, a resin film having a CTE of 5 ppm / K or more and 50 ppm / K or less can be obtained.

[0024] In the above-described configuration, the filler is preferably silica. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a method for manufacturing a resin film and a pre-cut film that can more effectively prevent film tearing when both ends of the film are gripped by a tenter-type conveying device. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a side cross-sectional view illustrating a method for applying a resin composition solution according to the first embodiment. [Figure 2] FIG. 2 is a plan view of FIG. [Figure 3] 3 is an enlarged plan view of a portion near a side plate 18b shown in FIG. 2. FIG. [Figure 4] FIG. 10 is a cross-sectional view showing a case where each coating film is connected only at the side surface. [Figure 5] FIG. 10 is a cross-sectional view showing a case where the coating film 64a and the coating film 64c slightly overlap on the coating film 64b. [Figure 6] FIG. 10 is a cross-sectional view showing a case where a coating film 64b slightly overlaps the coating films 64a and 64c. [Figure 7]FIG. 10 is a side cross-sectional view illustrating a method for applying a resin composition solution according to a second embodiment. [Figure 8] FIG. 8 is a plan view of FIG. [Figure 9] FIG. 10 is a side cross-sectional view illustrating a method for applying a resin composition solution according to a third embodiment. [Figure 10] FIG. 10 is a plan view of FIG. 9. [Figure 11] FIG. 10 is a cross-sectional view showing a case where the end of the coating film 64a slightly overlaps the end of the coating film 64b, and the end of the coating film 64b slightly overlaps the end of the coating film 64c. [Figure 12] FIG. 10 is a side cross-sectional view illustrating a method for applying a resin composition solution according to a fourth embodiment. [Figure 13] FIG. 13 is a plan view of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an embodiment of the present invention will be described.

[0028] [Manufacturing method of resin film] The method for producing a resin film according to this embodiment includes the steps of: A step A of applying a first resin composition solution to a central portion of a support; Step B: applying a second resin composition solution to both end portions adjacent to the central portion; a step C of drying the first resin composition solution and the second resin composition solution to obtain a pre-cut film; a step D of peeling the pre-cut film from the support; and a step E of holding both ends of the pre-cut film with a tenter-type conveying device after the step D. a step F of conveying the pre-cut film while holding both end portions of the pre-cut film; and After the step F, a step G is performed in which the portion formed from the second resin composition solution is removed from the pre-cut film to obtain a resin film. and the first resin composition solution contains a first resin and a filler, and the content of the filler is 0.1% by mass or more and 50% by mass or less with respect to the first resin; the second resin composition solution contains a second resin and does not contain a filler, or if it contains a filler, the content of the filler is less than that of the first resin composition solution and is 2 mass % or less relative to the second resin; After step C and before step F, the pre-cut film is characterized in that the tear strength of the portion formed from the second resin composition solution is greater than the tear strength of the portion formed from the first resin composition solution.

[0029] <Process A, Process B> In the method for producing a resin film according to this embodiment, first, a first resin composition solution is applied to the center of a support (step A). ​​Then, a second resin composition solution is applied to both end portions adjacent to the center (step B). Steps A and B may be performed simultaneously, or step A may be performed after step B, or step B may be performed after step A.

[0030] The support is not particularly limited, but is preferably one that is resistant to the solvents of the first resin composition solution and the second resin composition solution, and examples thereof include polymer films made of resins such as PET (polyethylene terephthalate), PI (polyimide), and PAI (polyamideimide), metal drums, endless steel belts, etc. Among these, polymer films are preferred.

[0031] The coating methods in the steps A and B are not particularly limited, and examples thereof include comma coating, T-die coating, spin coating, spray coating, bar coating, knife coating, and dipping. Two of these methods may be combined. Comma coating, T-die coating, or a combination thereof is preferred from the viewpoint of productivity.

[0032] Specific examples of steps A and B will be described below.

[0033] [First embodiment] FIG. 1 is a side cross-sectional view for explaining the method for applying a resin composition solution according to the first embodiment, and FIG. 2 is a plan view thereof. As shown in FIGS. 1 and 2, the coating device 10 has a backup roll 12, a comma roll 14, and three coating liquid storage sections 16 (16a, 16b, 16c). The coating liquid storage section 16 (16a, 16b, 16c) has four side plates 18 (18a, 18b, 18c, 18d) for dividing the coating liquid storage section 16, and a back plate 20. The coating liquid storage section 16 (16a, 16b, 16c) can store the coating liquid 62 in the area surrounded by the back plate 20 and the side plates 18.

[0034] Of the three coating liquid storage sections 16 (16a, 16b, 16c), the coating liquid storage sections 16a and 16c located at both ends store second resin composition solutions 62a and 62c, and the coating liquid storage section 16b located in the center stores the first resin composition solution 62b.

[0035] The backup roll 12 rotates to continuously transport the support 60. The support 60 transported by the backup roll 12 passes through a gap 22 formed between the backup roll 12 and the comma roll 14. When the support 60 passes through the gap 22, a coating liquid 62 (second resin composition solutions 62a, 62c, first resin composition solution 62b) is supplied from the coating liquid reservoir 16 onto the support 60, and a coating film 64 (64a, 64b, 64c) is formed. Specifically, the coating film 64 is formed to a thickness corresponding to the gap 22 minus the thickness of the support 60.

[0036] The thickness of the coating film 64 can be controlled by the gap 22 between the backup roll 12 and the comma roll 14, etc.

[0037] FIG. 3 is a partially enlarged plan view of the vicinity of the side plate 18b shown in FIG. Each coating liquid 62 (second resin composition solutions 62a, 62c, first resin composition solution 62b) is coated on the support 60 and then spreads in the width direction. Specifically, as shown in FIG. 3, the second resin composition solution 62a coated near the side plate 18b spreads inward in the width direction (to the right in FIGS. 2 and 3). On the other hand, the first resin composition solution 62b coated near the side plate 18b spreads outward in the width direction (to the left in FIGS. 2 and 3). Then, the second resin composition solution 62a (coating film 64a) and the first resin composition solution 62b (coating film 64b) are connected at a location where the side plate 18b disappears in the flow direction (upper side in FIGS. 2 and 3). Similarly, the first resin composition solution 62b applied near the side plate 18c spreads outward in the width direction (to the right in FIG. 2). On the other hand, the second resin composition solution 62c applied near the side plate 18c spreads inward in the width direction (to the left in FIG. 2). Then, the first resin composition solution 62b (coating film 64b) and the second resin composition solution 62c (coating film 64c) are connected at the point where the side plate 18c disappears in the flow direction. As a result, the coating film 64a and the coating film 64b are connected to each other, and the coating film 64b and the coating film 64c are also connected to each other. Examples of the connection include connection due to compatibility between the resin composition solutions constituting each coating film 64, and connection due to adhesive force at the interface between each coating film 64.

[0038] The connection mode of each coating film 64 is not particularly limited, but examples include when each coating film is connected only on the side (see Figure 4), or when one coating film slightly overlaps the other coating film (see Figures 5 and 6).

[0039] FIG. 4 is a cross-sectional view showing a case where the coating films are connected only on the side surfaces. In the example shown in FIG. 4, the coating film 64a and the coating film 64b are connected only at their side surfaces. The coating film 64b and the coating film 64c are connected only at their side surfaces. Immediately after coating, the two films are connected only at their side surfaces. However, immediately before the subsequent step C, the second resin composition solution 62a (coating film 64a) and the first resin composition solution 62b (coating film 64b), or the first resin composition solution 62b (coating film 64b) and the second resin composition solution 62c (coating film 64c), mix together to form a compositionally gradient region. The width of the compositionally gradient region is preferably 10 to 2,500 times the thickness of the coating film 64b in the non-compositionally gradient region. It is more preferably 100 to 1,000 times, and even more preferably 250 to 500 times. For example, when the thickness of the coating film 64b is 20 μm, the width of the compositionally graded region is preferably 0.2 mm (10 times the thickness of the coating film 64b) to 5 cm (2500 times the thickness of the coating film 64b).Within this range, fracture from the compositionally graded region during manufacturing is unlikely to occur.

[0040] FIG. 5 is a cross-sectional view showing a case where the coating film 64a and the coating film 64c slightly overlap on the coating film 64b. In the example shown in FIG. 5, the edge of the coating film 64a slightly overlaps the edge of the coating film 64b. Similarly, the edge of the coating film 64c slightly overlaps the edge of the coating film 64b. The overlapping portions form a compositionally gradient region by mixing the second resin composition solution 62a (coating film 64a) with the first resin composition solution 62b (coating film 64b), or the first resin composition solution 62b (coating film 64b) with the second resin composition solution 62c (coating film 64c). The width of the compositionally gradient region is preferably 10 to 2,500 times the thickness of the non-compositionally gradient region of the coating film 64b, more preferably 100 to 1,000 times, and even more preferably 250 to 500 times. For example, when the thickness of the coating film 64b is 20 μm, the width of the compositionally gradient region is preferably 0.2 mm (10 times the thickness of the coating film 64b) to 5 cm (2,500 times the thickness of the coating film 64b). Within this range, fracture from the composition gradient region is unlikely to occur during manufacturing.

[0041] FIG. 6 is a cross-sectional view showing a case where the coating film 64b slightly overlaps the coating films 64a and 64c. In the example shown in Figure 6, the end of coating film 64b (the end on the left in Figure 6) slightly overlaps coating film 64a. Also, the end of coating film 64b (the end on the right in Figure 6) slightly overlaps coating film 64c. As in the case of Figure 5, the width of the overlapping portion is preferably in the range of 10 to 2500 times the width of the coating film 64b in the portion that is not the compositionally gradient region. More preferably, it is 100 to 1000 times, and even more preferably, it is 250 to 500 times. Within this range, fracture from the compositionally gradient region is less likely to occur during manufacturing.

[0042] The connection mode can be determined, for example, by the gap 22. If the gap 22 through which the second resin composition solutions 62a and 62c pass is the same as the gap 22 through which the first resin composition solution 62b passes, the connection mode shown in FIG. 4 is likely to be achieved. If the gap 22 through which the second resin composition solutions 62a and 62c pass is slightly wider than the gap 22 through which the first resin composition solution 62b passes, the connection mode shown in FIG. 5 is likely to be achieved. If the gap 22 through which the first resin composition solution 62b passes is slightly wider than the gap 22 through which the second resin composition solutions 62a and 62c pass, the connection mode shown in FIG. 6 is likely to be achieved. Note that the connection mode can be controlled not only by the gap 22 but also by the viscosity of the first resin composition solutions 62b and the second resin composition solutions 62a and 62c and the width of the side plate 18.

[0043] In the first embodiment, the process A and the process B are carried out simultaneously by the coating apparatus 10 described above.

[0044] Step A and step B according to the first embodiment have been described above.

[0045] [Second embodiment] Fig. 7 is a side cross-sectional view for explaining the method for applying a resin composition solution according to the second embodiment, and Fig. 8 is a plan view thereof. In the application device 30 of the second embodiment, components common to the application device 10 of the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0046] 7 and 8, the coating device 30 has a backup roll 12, a comma roll 14, and two coating liquid storage sections 16 (16a, 16c) on both sides in the width direction. The coating liquid storage sections 16 (16a, 16c) are capable of storing a coating liquid 62 in an area surrounded by a back plate 20 and a side plate 18.

[0047] The two coating liquid storage sections 16 (16a, 16c) store second resin composition solutions 62a, 62c. Unlike the first embodiment, the coating device 30 according to the second embodiment does not store the first resin composition solution in the coating liquid storage section 16.

[0048] The backup roll 12 rotates to continuously transport the support 60. The support 60 transported by the backup roll 12 passes through a gap 22 formed between the backup roll 12 and a comma roll 14. When the support 60 passes through the gap 22, second resin composition solutions 62a and 62c are supplied from the coating liquid reservoir 16 onto the support 60, and coating films 64a and 64c are formed.

[0049] The coating device 30 further includes a T-die coater 32. The T-die coater 32 is installed downstream of the backup roll 12 and the comma roll 14. The T-die coater 32 is installed so that its discharge port is located above the center of the support 60.

[0050] When the support 60 on which the coating films 64a and 64c have been formed is transported, the T-die coater 32 applies the first resin composition solution 62b to the center of the support 60.

[0051] In the second embodiment, step B is performed first using the coating device 30 described above, followed by step A. In the second embodiment, the connection of each coating film 64 is likely to be the connection shown in FIG. 6, but is not limited to this. As a modification of the second embodiment, the first resin composition solution may be applied to the center of the support using a comma coater, and then the second resin composition solution may be applied to both end portions using a T-die coater.

[0052] Step A and step B according to the second embodiment have been described above.

[0053] [Third embodiment] Fig. 9 is a side cross-sectional view for explaining the method for applying a resin composition solution according to the third embodiment, and Fig. 10 is a plan view thereof. In the application device 40 of the third embodiment, components common to the application device 30 of the second embodiment are designated by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0054] The coating device 40 includes a T-die coater 42a, a T-die coater 42b, and a T-die coater 42c. The T-die coater 42a and the T-die coater 42c are installed in a stage before the T-die coater 42b. The T-die coater 42a and the T-die coater 42c are each installed so that their discharge outlets are located above the ends of the support 60. In FIG. 10 , the T-die coater 42a is installed so that its discharge outlet is located above the left end of the support 60, and the T-die coater 42c is installed so that its discharge outlet is located above the right end of the support 60. The T-die coater 42 b is installed so that the discharge port is located above the center of the support 60 .

[0055] When the support 60 on which the coating films 64a and 64c have been formed is transported, the T-die coater 42b applies the first resin composition solution 62b to the center of the support 60.

[0056] In the third embodiment, the bonding mode of each coating film 64 tends to be the bonding mode shown in Fig. 5, but is not limited to this. As a modification of the third embodiment, the second resin composition may be applied to both end portions with a T-die coater, and then the first resin composition may be applied to the center portion with a T-die coater. In this case, the bonding mode of each coating film 64 tends to be the bonding mode shown in Fig. 6, but is not limited to this. Furthermore, as another modified example, the second resin composition may be applied to one end using a T-die coater, then the first resin composition may be applied to the center using a T-die coater, and then the second resin composition may be applied to the other end using a T-die coater. In this case, the bonding mode of each coating film 64 tends to be the bonding mode shown in FIG. 11, but is not limited to this. 11, the edge of the coating film 64a slightly overlaps the coating film 64b, and the edge of the coating film 64b (the edge on the right side in FIG. 11) slightly overlaps the coating film 64c. As shown in the third embodiment and its modified example, step A and step B may be performed by arranging multiple T-die coaters in a vertical line and successively applying the first resin composition and the second resin composition.

[0057] [Fourth embodiment] Fig. 12 is a side cross-sectional view for explaining the method for applying a resin composition solution according to the fourth embodiment, and Fig. 13 is a plan view thereof. In the application device 50 of the fourth embodiment, components common to the application device 40 of the third embodiment are designated by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0058] The coating device 50 includes a T-die coater 52 having a discharge port divided into three in the width direction. The T-die coater 52 coats the first resin composition on the center of the support 60 and simultaneously coats the second resin composition on both end portions.

[0059] 12 and 13, in the fourth embodiment, the first resin composition and the second resin composition are simultaneously applied in steps A and B. In the fourth embodiment, the bonding mode of each coating film 64 tends to be the bonding mode shown in FIG.

[0060] <Process C> After steps A and B, the first resin composition solution and the second resin composition solution are dried to obtain a pre-cut film (step C). Drying conditions can be appropriately set within a range that allows the solvent to be sufficiently evaporated, and for example, the drying temperature can be in the range of 60°C to 140°C, and the drying time can be in the range of 1 minute to 60 minutes. The drying conditions are particularly suitable when dimethylacetamide is used as the solvent, since its boiling point is 165°C. After step C and before step D, a step (step C-1) of winding up the pre-cut film together with the support into a roll may be performed. In this case, the pre-cut film may be unwound again before step D.

[0061] <Process D> After step C, the pre-cut film is peeled off from the support (step D). The method for peeling off the pre-cut film from the support is not particularly limited, but may include a method of rolling up from the edge using tweezers, a method of making a slit in the pre-cut film and attaching adhesive tape to one side of the slit and then rolling up from the tape, or a method of vacuum-adsorbing one side of the slit in the pre-cut film and then rolling up from that side. As a rolling up method, it is desirable to roll up while winding it up on a roll. Methods for making cuts in the pre-cut film include, but are not limited to, a method of cutting the pre-cut film with a cutting tool such as a blade, a method of cutting the pre-cut film with a laser, a method of cutting the pre-cut film with a water jet, etc. For example, when employing the above-mentioned methods, it is also possible to appropriately employ a technique such as superimposing ultrasonic waves on the cutting tool or adding a reciprocating motion or an up-and-down motion to improve cutting performance. After step D and before step E, a step (step D-1) of winding the pre-cut film into a roll may be performed. In this case, the pre-cut film may be unwound again before step E. When winding the pre-cut film, it is preferable to sandwich an interleaf paper (anti-blocking film) therebetween. By carrying out the step C-1 and / or the step D-1, it becomes possible to provide a certain period of time after the drying step (step C) before carrying out the cutting step (step G). After the drying step (step C), the cut film is wound up once and kept in that state for a certain period of time, thereby making it possible to equalize the distribution of the solvent in the thickness direction of the film. This point will be explained below. As shown in Figures 5 and 6, when two coating films overlap slightly, the solvent distribution in the film immediately after drying on the support is such that the amount of solvent remaining in the coating film on the support side is greater than the amount of solvent remaining in the coating film on the surface side. If a heating step (e.g., step F described below) is performed in this state, a difference in the amount of solvent volatilization occurs, and this part (the overlapping part) may be prone to tearing. Therefore, by carrying out the steps C-1 and / or D-1 and equalizing the solvent distribution in the thickness direction of the overlapping portion, the amount of remaining solvent in the two types of coating films becomes relatively equal, making it possible to make the overlapping portion less likely to tear. After step C-1 and / or step D-1, the rolled state is maintained for preferably 30 minutes or more, more preferably 3 hours or more. By maintaining the rolled state for this period, the solvent can be suitably diffused in the thickness direction. Furthermore, when the steps C-1 and / or D-1 are performed, the pre-cut film is wound up once during the process, which allows the production equipment to be made compact. In other words, if all the steps are connected continuously, the production line will be quite long, which may impose restrictions on factory location, etc. On the other hand, if the winding step is performed during production, the production line can be divided into two, and the two divided lines can be arranged in parallel, allowing for a relatively compact production equipment. Furthermore, by winding the film once during production, quality checks can be performed during the process.

[0062] <Process E> After step D, both ends of the pre-cut film are gripped by a tenter-type conveying device (step E). Specifically, when a pin tenter-type conveying device is used as the tenter-type conveying device, both ends of the pre-cut film are gripped by being stuck into multiple pins of the pin tenter-type conveying device. When a clip tenter-type conveying device is used as the tenter-type conveying device, both ends of the pre-cut film are gripped by being clamped between multiple clips of the clip tenter-type conveying device. As the tenter-type conveying device, a conventionally known device (for example, the tenter-type conveying device disclosed in Japanese Patent No. 4843996 and Japanese Patent No. 4821960) can be used.

[0063] <Process F> After step E, the pre-cut film is transported while both ends of the pre-cut film are held (step F). The film may be heated during transportation. The heating temperature is not particularly limited, but when the first resin composition solution and the second resin composition solution are polyimide-based resin composition solutions, the heating temperature may be, for example, 150°C to 500°C and 1 minute to 60 minutes. In steps E and F, the pre-cut film may or may not be stretched in the width direction.

[0064] In step F, the pre-cut film usually shrinks in the width direction during transport. Therefore, a tensile force is applied to the portion held by the tenter-type transport device. Here, as will be described in detail later, the tear strength of the pre-cut film at both ends (portions formed from the second resin composition solution) is greater than the tear strength of the center portion (portion formed from the second resin composition solution). Therefore, tearing of the pre-cut film at the held portions (both ends) is suppressed. In particular, when a pin tenter-type transport device is used as the tenter-type transport device, tearing due to the pins of the pin tenter-type transport device is more suitably suppressed.

[0065] <Process G> After step F, the portion formed from the second resin composition solution is removed from the pre-cut film to obtain a resin film (step G). In step G, it is sufficient to remove at least the portion formed from the second resin composition solution, and a portion of the portion formed from the first resin composition solution may also be removed along with the portion formed from the second resin composition solution. The resin film obtained in this manner consists only of the portion formed from the first resin composition solution. In other words, a resin film consisting only of portions with relatively low tear strength is obtained.

[0066] The CTE (coefficient of linear thermal expansion) of the resin film is 5 ppm / K or more and 50 ppm / K or less. To improve heat resistance, it is preferably 45 ppm / K or less, more preferably 40 ppm / K or less, and even more preferably 35 ppm / K or less. From an industrial perspective, it may be 6 ppm / K or more, or even 7 ppm / K or more.

[0067] The thickness of the resin film is not particularly limited, but is preferably 5 μm to 125 μm, more preferably 7.5 μm to 75 μm, and even more preferably 12.5 μm to 50 μm.

[0068] The method for removing the portion formed from the second resin composition solution from the pre-cut film is not particularly limited, and a conventionally known slitter or the like can be used.

[0069] As described above, according to the resin film manufacturing method of this embodiment, even a resin film with low tear strength can be transported using a conventionally known tenter-type transport device. Furthermore, because both end portions of the pre-cut film are formed only from the second resin composition solution, it is possible to minimize waste of raw materials associated with the portions removed in step G.

[0070] The first resin composition solution and the second resin composition solution will be described below.

[0071] The first resin composition solution and the second resin composition solution are not particularly limited, as long as the tear strength of the portion of the pre-cut film formed from the second resin composition solution after step C and before step F is greater than the tear strength of the portion formed from the first resin composition solution, and the CTE of the resin film is 5 ppm / K or more and 50 ppm / K or less.

[0072] The first resin composition solution contains a first resin and a filler, and the content of the filler is 0.1% by mass or more and 50% by mass or less with respect to the first resin.

[0073] The first resin is not particularly limited as long as it can be a resin capable of being solution-formed into a film, and it may be a resin or a precursor of that resin. From an industrial perspective, it is particularly preferred for resins that are difficult to form into a film from a melt. Specific examples include cellulose triacetate, aromatic polyamide, polyimide, polyetherimide, polyamideimide, polyesterimide, polybenzoxazole, polybenzimidazole, and polybenzothiazole. Polyamic acid is also an example of a polyimide precursor. Among these, polyimide-based resins such as polyimide, polyamideimide, polyetherimide, and polyimidebenzoxazole are particularly preferred.

[0074] The content of the filler in the first resin composition solution is 0.1% by mass or more relative to the first resin. Because this allows for a reduction in the CTE of the resin film, it is preferably 0.2% by mass or more, and more preferably 0.3% by mass or more. Furthermore, the content of the filler in the first resin composition solution is 50% by mass or less relative to the first resin. Because this improves the mechanical properties of the resin film, it is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and particularly preferably 15% by mass or less.

[0075] The first resin composition solution preferably contains a predetermined amount of the first resin and a filler. Specific examples include a cellulose triacetate resin composition solution, a polyetherimide resin composition solution, a polyesterimide resin composition solution, a polybenzoxazole resin composition solution, a polybenzimidazole resin composition solution, a polybenzothiazole resin composition solution, a polyimide resin composition solution, an aromatic polyamide resin composition solution, and a polyamideimide resin composition solution. Among these, a polyimide resin composition solution is preferred. Among polyimide resin films, those generally referred to as transparent polyimides often have low tear strength. However, according to the resin film manufacturing method of this embodiment, even transparent polyimide resin films with low tear strength can be suitably manufactured.

[0076] From the viewpoints of operability (applicability) and economy, the concentration of the first resin in the first composition solution is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 40% by mass or less.

[0077] The first polyimide resin composition solution may be a polyamic acid (polyimide precursor) solution or a polyimide solution. When a polyamic acid solution is used, a dehydration ring-closing reaction is carried out by heat treatment in step F to form a polyimide film. When a polyimide solution is used, a polyimide film is formed by volatilizing the solvent in step C. The heat treatment conditions can be appropriately set within a range that allows the polyamic acid to react with the polyimide. The heat treatment temperature can be set, for example, in the range of 250 to 500°C, preferably in the range of 300 to 400°C. The heat treatment time can be appropriately set depending on the heat treatment temperature, for example, in the range of 5 to 60 minutes, preferably in the range of 10 to 30 minutes.

[0078] The polyamic acid solution is obtained by reacting a diamine with a tetracarboxylic acid in a solvent.

[0079] As the tetracarboxylic acids, aromatic tetracarboxylic acids (including their acid anhydrides), aliphatic tetracarboxylic acids (including their acid anhydrides), and alicyclic tetracarboxylic acids (including their acid anhydrides) commonly used in polyimide synthesis can be used. Among these, aromatic tetracarboxylic acid anhydrides and alicyclic tetracarboxylic acid anhydrides are preferred, with aromatic tetracarboxylic acid anhydrides being more preferred from the viewpoint of heat resistance and alicyclic tetracarboxylic acids being more preferred from the viewpoint of light transmittance. When these are acid anhydrides, they may have one or two anhydride structures in the molecule, but preferably have two anhydride structures (dianhydrides). Tetracarboxylic acids may be used alone or in combination of two or more.

[0080] Among the polyamic acid solutions, a solution capable of producing a colorless and highly transparent polyimide is preferred.

[0081] Aromatic tetracarboxylic acids for obtaining colorless and highly transparent polyimides include 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid, 4,4'-oxydiphthalic acid, 3,4'-oxydiphthalic acid, bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-carboxylic acid)1,4-phenylene, bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-yl)benzene-1,4-dicarboxylate, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(benzene)], and the like. 4,4'-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(1,4-xylene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(4-isopropyl-toluene) 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(naphthalene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(benzene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-benzophenonetetracarboxylic acid, 4,4'-[(3H-2,1-benzoxathiol-1,1 -dioxide-3,3-diyl)bis(toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(1,4-xylene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(4-isopropyl-toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,

[0039] tetracarboxylic acids such as 1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(naphthalene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 3,3',4,4'-diphenylsulfonetetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 2,2',3,3'-biphenyltetracarboxylic acid, pyromellitic acid, 4,4'-[spiro(xanthene-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]diphthalic acid, and 4,4'-[spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]diphthalic acid, and acid anhydrides thereof. Among these, dianhydrides having two acid anhydride structures are preferred, and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride and 4,4'-oxydiphthalic dianhydride are particularly preferred. The aromatic tetracarboxylic acids may be used alone or in combination of two or more. When heat resistance is important, the aromatic tetracarboxylic acids preferably account for 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0082] Examples of alicyclic tetracarboxylic acids include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,2,3,4-cyclohexanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3',4,4'-bicyclohexyltetracarboxylic acid, bicyclo[2,2,1]heptane-2,3,5,6-tetracarboxylic acid, bicyclo[2,2,2]octane-2,3,5,6-tetracarboxylic acid, and bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid. carboxylic acid, tetrahydroanthracene-2,3,6,7-tetracarboxylic acid, tetradecahydro-1,4:5,8:9,10-trimethanoanthracene-2,3,6,7-tetracarboxylic acid, decahydronaphthalene-2,3,6,7-tetracarboxylic acid, decahydro-1,4:5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic acid, decahydro-1,4-ethano-5,8-methanonaphthalene-2,3,6,7-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane -5,5'',6,6''-tetracarboxylic acid (synonym: norbornane-2-spiro-2'-cyclopentanone-5'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid), methylnorbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-(methylnorbornane)-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclohexanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid (synonym: norbornane-2-spiro pyro-2'-cyclohexanone-6'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid), methylnorbornane-2-spiro-α-cyclohexanone-α'-spiro-2''-(methylnorbornane)-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclopropanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclobutanone-α'-spiro-2''-norbornane-5,5'',6,6''-Tetracarboxylic acid, norbornane-2-spiro-α-cycloheptanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclooctanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclononanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclodecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cycloundecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclododecanone-α'-spiro-2''-norbornane-5,5'' ,6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclotridecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclotetradecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentadecanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-(methylcyclopentanone)-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, and norbornane-2-spiro-α-(methylcyclohexanone)-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, and acid anhydrides thereof. Among these, dianhydrides having two acid anhydride structures are preferred, and in particular, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclohexanetetracarboxylic dianhydride, and 1,2,4,5-cyclohexanetetracarboxylic dianhydride are preferred, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2,4,5-cyclohexanetetracarboxylic dianhydride are more preferred, and 1,2,3,4-Cyclobutanetetracarboxylic dianhydride is more preferred. These may be used alone or in combination of two or more. When transparency is important, the alicyclic tetracarboxylic acids preferably account for 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more.

[0083] The polyamic acid solution may contain tricarboxylic acids and dicarboxylic acids.

[0084] Examples of tricarboxylic acids include aromatic tricarboxylic acids such as trimellitic acid, 1,2,5-naphthalenetricarboxylic acid, diphenylether-3,3',4'-tricarboxylic acid, and diphenylsulfone-3,3',4'-tricarboxylic acid, hydrogenated versions of these aromatic tricarboxylic acids such as hexahydrotrimellitic acid, alkylene glycol bistrimellitates such as ethylene glycol bistrimellitate, propylene glycol bistrimellitate, 1,4-butanediol bistrimellitate, and polyethylene glycol bistrimellitate, and monoanhydrides and esters thereof. Among these, monoanhydrides having one acid anhydride structure are preferred, with trimellitic anhydride and hexahydrotrimellitic anhydride being particularly preferred. These may be used alone or in combination.

[0085] Examples of dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid, hydrogenated versions of these aromatic dicarboxylic acids such as 1,6-cyclohexanedicarboxylic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, azelaic acid, sebacic acid, undecadioic acid, dodecanedioic acid, and 2-methylsuccinic acid, as well as their acid chlorides and esters. Among these, aromatic dicarboxylic acids and their hydrogenated versions are preferred, with terephthalic acid, 1,6-cyclohexanedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid being particularly preferred. The dicarboxylic acids may be used alone or in combination.

[0086] The diamines or isocyanates used to obtain colorless and highly transparent polyimides are not particularly limited, and aromatic diamines, aliphatic diamines, alicyclic diamines, aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and the like, which are commonly used in polyimide synthesis, polyamideimide synthesis, and polyamide synthesis, can be used. From the viewpoint of heat resistance, aromatic diamines are preferred, and from the viewpoint of transparency, alicyclic diamines are preferred. Furthermore, the use of aromatic diamines having a benzoxazole structure makes it possible to achieve high heat resistance, as well as a high elastic modulus, low heat shrinkage, and a low coefficient of linear expansion. Diamines and isocyanates can be used alone or in combination of two or more.

[0087] Examples of aromatic diamines include 2,2'-dimethyl-4,4'-diaminobiphenyl, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, and bis[4-(3-aminophenoxy)phenyl] Sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 4-amino-N-(4-aminophenyl)benzamide, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4, 4'-Diaminodiphenyl ether, 2,2'-trifluoromethyl-4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzo Phenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis[4-(4-aminophenoxy)phenyl]methane, 1,1-bis[4-(4-aminophenoxy)phenyl]ethane, 1,2-bis[4-(4-aminophenoxy)phenyl]ethane, 1,1-bis[4-(4-aminophenoxy)phenyl]propane, 1,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,1-bis[4-(4-aminophenoxy)phenyl]butane, 1,3-bis[4-(4-aminophenoxy)phenyl]butane, 1,4-bis[4-(4-aminophenoxy)phenyl]butane, 2,2-bis[4-(4-aminophenoxy)phenyl]butane, 2,3-bis[4-(4-aminophenoxy)phenyl]butane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)phenyl] )-3-methylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)-3-methylphenyl]propane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,4-bis(3-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfoxide, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,3-bis [4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 4,4'-bis[(3-aminophenoxy)benzoyl]benzene, 1,1-bis[4-(3-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)phenyl]propane, 3,4'-diaminodiphenyl sulfide, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis[4-(3-aminophenoxy)phenyl]methane, 1,1-Bis[4-(3-aminophenoxy)phenyl]ethane, 1,2-bis[4-(3-aminophenoxy)phenyl]ethane, bis[4-(3-aminophenoxy)phenyl]sulfoxide, 4,4'-bis[3-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[3-(3-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenone Nilsulfone, bis[4-{4-(4-aminophenoxy)phenoxy}phenyl]sulfone, 1,4-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-trifluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-fluorophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino -6-methylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-cyanophenoxy)-α,α-dimethylbenzyl]benzene, 3,3'-diamino-4,4'-diphenoxybenzophenone, 4,4'-diamino-5,5'-diphenoxybenzophenone, 3,4'-diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino 3,3'-Diamino-4,4'-Diamino-5'-Phenoxybenzophenone, 3,3'-Diamino-4,4'-Diamino-5,5'-Diamino-5'-Diamino-4'-Diamino-5'-Diamino-4'-Diamino-5'-Diamino-4'-Diamino-5'-Diamino-4'-Diamino-5'-Diamino-4'-Diamino-5'-Diamino-4'-Diamino-5'-Diamino-4'-Diamino-5'-Diamino-4'-Diamino-5'-Diamino-1,3-Bis(3-amino-4-phenoxybenzoyl)benzene, 1,3-Bis(3-amino-4-phenoxybenzoyl)benzene, 1,4-bis(3-amino-4-phenoxybenzoyl)benzene, 1,3-bis(4-amino-5-phenoxybenzoyl)benzene, 1,4-bis(4-amino-5-phenoxybenzoyl)benzene, 1,3-bis(3-amino-4-biphenoxybenzoyl)benzene, 1,4-bis(3-amino-4-biphenoxybenzoyl)benzene, 1,3-bis(4-amino-5-biphenoxybenzoyl)benzene, 1,4-bis(4-amino-5-biphenoxybenzoyl)benzene, 2,6-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzonitrile, 4,4'-[9H-fluorene-9,9-diyl]bisaniline (also known as "9,9-bis(4-aminophenyl)fluorene"), [spiro(xanthene-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]bisaniline, 4,4'-[spiro(xanthene-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]bisaniline, 4,4'-[spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]bisaniline, and aromatic diamines in which some or all of the hydrogen atoms on the aromatic ring of the above aromatic diamines have been substituted with halogen atoms, alkyl or alkoxy groups having 1 to 3 carbon atoms, cyano groups, or halogenated alkyl or alkoxy groups having 1 to 3 carbon atoms in which some or all of the hydrogen atoms of the alkyl or alkoxy groups have been substituted with halogen atoms. The aromatic diamines having a benzoxazole structure are not particularly limited, and examples thereof include 5-amino-2-(p-aminophenyl)benzoxazole, 6-amino-2-(p-aminophenyl)benzoxazole, 5-amino-2-(m-aminophenyl)benzoxazole, 6-amino-2-(m-aminophenyl)benzoxazole, 2,2'-p-phenylenebis(5-aminobenzoxazole), 2,2'-p-phenylenebis(6-aminobenzoxazole), 1-(5-aminobenzoxazolo)-4-(6-aminobenzoxazolo)benzene, 2,6-(4,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(4,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, 2,Examples of suitable aromatic diamines include 6-(3,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, and 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole. Among these, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4-amino-N-(4-aminophenyl)benzamide, 4,4'-diaminodiphenyl sulfone, and 3,3'-diaminobenzophenone are particularly preferred. The aromatic diamines may be used alone or in combination.

[0088] Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, and 4,4'-methylenebis(2,6-dimethylcyclohexylamine). Among these, 1,4-diaminocyclohexane and 1,4-diamino-2-methylcyclohexane are particularly preferred, and 1,4-diaminocyclohexane is more preferred. The alicyclic diamines may be used alone or in combination.

[0089] Examples of diisocyanates include diphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-diethyl Diphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4'-diisocyanate, diphenylether-4,4' -Diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-(2,2-bis(4-phenoxyphenyl)propane)diisocyanate, 3,3'- or 2,2'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'- or 2,2'-di Examples of the diisocyanate include aromatic diisocyanates such as ethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, and 3,3'-diethoxybiphenyl-4,4'-diisocyanate, and diisocyanates obtained by hydrogenating any of these (for example, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate).Among these, diphenylmethane-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate are preferred from the viewpoints of low moisture absorption, dimensional stability, cost, and polymerizability. The diisocyanates may be used alone or in combination.

[0090] The solvent may be any solvent capable of dissolving polyimide or a polyimide precursor, and aprotic polar solvents are suitable. Examples include N,N-di-lower alkylcarboxylamides such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, and N,N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, dimethyl sulfone, 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, diglyme, m-cresol, hexamethylphosphoramide, N-acetyl-2-pyrrolidone, hexamethylphosphoramide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, and p-chlorophenol. The solvent may be a mixture of two or more solvents.

[0091] The filler is not particularly limited, but examples thereof include organic particles and inorganic particles, with inorganic particles being particularly preferred. Examples of inorganic particles include metal oxide particles such as silica, zirconia, alumina, titania, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, and cerium oxide, and metal fluoride particles such as magnesium fluoride and sodium fluoride. Transparent or colorless fillers are preferred. Silica is more preferred from the viewpoints of dispersibility in resins and heat resistance.

[0092] The shape of the filler is not particularly limited, and may be particulate or fibrous.

[0093] The size of the filler is not particularly limited, but is preferably 0.5 to 180 nm, and more preferably 2 to 100 nm. If the size is 0.5 nm or more, the low CTE effect of the resin film can be exhibited. Furthermore, if the size is 180 nm or less, the cloudiness, turbidity, or coloration of the resin film can be suppressed.

[0094] The fillers may be used alone or in combination.

[0095] The location of the filler present in the resin film is not particularly limited, but it may be dispersed throughout the resin film, may be concentrated in specific locations within the resin film, or may be exposed from the surface of the resin film.

[0096] The second resin composition solution contains a second resin and does not contain a filler, or if it does contain a filler, the content is less than that of the first resin composition solution and is 2 mass % or less relative to the second resin.

[0097] The second resin composition solution does not contain a filler, or if it does contain a filler, the content is less than that of the first resin composition solution and is 2% by mass or less relative to the second resin. The amount of filler relative to the second resin is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0% by mass, in order to improve the tear strength at both ends.

[0098] The second resin is not particularly limited as long as it can be solution-formed into a film and has a tear strength greater than that of the first resin when formed into a film. It may have the same composition as the first resin or a different composition. Specific examples include cellulose triacetate, aromatic polyamide, polyimide, polyetherimide, polyamideimide, polyesterimide, polybenzoxazole, polybenzimidazole, and polybenzothiazole. Polyamic acid is also an example of a polyimide precursor. Among these, polyimide-based resins such as polyimide, polyamideimide, polyetherimide, and polyimidebenzoxazole are particularly preferred. Examples of the second resin composition solution include polyimide-based resin composition solutions, polyamide-based resin composition solutions, and polyamideimide-based resin composition solutions. When a polyimide-based resin composition solution is used as the first resin composition solution, it is preferable to use a polyimide-based resin composition solution as the second resin composition solution, as their heat resistance is similar. It is preferable that the second resin composition solution has heat resistance equal to or greater than that of the first resin composition solution.

[0099] From the viewpoints of operability (applicability) and economy, the concentration of the second resin in the second composition solution is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 80% by mass or less, more preferably 60% by mass or less, and even more preferably 40% by mass or less.

[0100] The second polyimide resin composition solution may be a polyamic acid (polyimide precursor) solution or a polyimide solution. When a polyamic acid solution is used, a dehydration ring-closing reaction is carried out by heat treatment in step F to form a polyimide film. When a polyimide solution is used, a polyimide film is formed by volatilizing the solvent in step C. The heat treatment conditions are the same as those for the first polyimide resin composition solution.

[0101] The polyamic acid solution is obtained by reacting diamines with tetracarboxylic dianhydrides in a solvent.

[0102] As the tetracarboxylic acids, aromatic tetracarboxylic acids (including their acid anhydrides), aliphatic tetracarboxylic acids (including their acid anhydrides), and alicyclic tetracarboxylic acids (including their acid anhydrides) that are commonly used in polyimide synthesis can be used. Among these, aromatic tetracarboxylic acid anhydrides and alicyclic tetracarboxylic acid anhydrides are preferred. The tetracarboxylic acids may be used alone or in combination of two or more.

[0103] Examples of alicyclic tetracarboxylic acids include alicyclic tetracarboxylic acids such as cyclobutane tetracarboxylic acid, 1,2,4,5-cyclohexane tetracarboxylic acid, and 3,3',4,4'-bicyclohexyl tetracarboxylic acid, as well as their acid anhydrides. Among these, dianhydrides having two anhydride structures (e.g., cyclobutane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, and 3,3',4,4'-bicyclohexyl tetracarboxylic dianhydride) are preferred. The alicyclic tetracarboxylic acids may be used alone or in combination of two or more. When transparency is important, the alicyclic tetracarboxylic acids preferably account for 80 mass % or more of the total tetracarboxylic acids, more preferably 90 mass % or more, and even more preferably 95 mass % or more.

[0104] The aromatic tetracarboxylic acids are not particularly limited, but examples thereof include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propanoic anhydride. When heat resistance is important, the aromatic tetracarboxylic acids preferably account for, for example, 80 mass % or more of all tetracarboxylic acids, more preferably 90 mass % or more, and even more preferably 95 mass % or more.

[0105] The diamines are not particularly limited, and aromatic diamines, aliphatic diamines, and the like, which are commonly used in polyimide synthesis, can be used. From the viewpoint of heat resistance, aromatic diamines are preferred, and among aromatic diamines, aromatic diamines having a benzoxazole structure are more preferred. Use of aromatic diamines having a benzoxazole structure makes it possible to achieve high heat resistance as well as high elastic modulus, low heat shrinkage, and low linear expansion coefficient. The diamines may be used alone or in combination of two or more.

[0106] The aromatic diamines having a benzoxazole structure are not particularly limited, and examples thereof include 5-amino-2-(p-aminophenyl)benzoxazole, 6-amino-2-(p-aminophenyl)benzoxazole, 5-amino-2-(m-aminophenyl)benzoxazole, 6-amino-2-(m-aminophenyl)benzoxazole, 2,2'-p-phenylenebis(5-aminobenzoxazole), 2,2'-p-phenylenebis(6-aminobenzoxazole), 1-(5-aminobenzoxazolo)-4-(6-aminobenzoxazolo)benzene, 2,6-(4,4'-diazomethane)-1,1-dimethyl-2,2-dibenzoxazole, 1-(5-aminobenzoxazolo)-4-(6-aminobenzoxazolo)benzene ... 2,6-(4,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, and the like.

[0107] Examples of aromatic diamines other than the above-mentioned aromatic diamines having a benzoxazole structure include 2,2'-dimethyl-4,4'-diaminobiphenyl, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene (bisaniline), 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl] ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether aminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodi Phenylmethane, bis[4-(4-aminophenoxy)phenyl]methane, 1,1-bis[4-(4-aminophenoxy)phenyl]ethane, 1,2-bis[4-(4-aminophenoxy)phenyl]ethane, 1,1-bis[4-(4-aminophenoxy)phenyl]propane, 1,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,1-bis[4-(4-aminophenoxy)phenyl]butane, 1,3-bis[4-(4-aminophenoxy)phenyl]butane, 1,4-bis[4-(4-aminophenoxy)phenyl]butane, 2,2-bis[4-(4-aminophenoxy)phenyl]butane, 2,3-bis[4-(4-aminophenoxy)phenyl]butane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)-3-methylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)-3-methylphenyl]propane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)phenyl]- bis(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,4-bis(3-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy) phenyl] sulfide, bis[4-(4-aminophenoxy)phenyl] sulfoxide, bis[4-(4-aminophenoxy)phenyl] sulfone, bis[4-(3-aminophenoxy)phenyl] ether, bis[4-(4-aminophenoxy)phenyl] ether, 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 4,4'-bis[(3-aminophenoxy)benzoyl]benzene, 1 ,1-bis[4-(3-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)phenyl]propane, 3,4'-diaminodiphenyl sulfide, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis[4-(3-aminophenoxy)phenyl]methane, 1,1-bis[4-(3-aminophenoxy)phenyl]ethane, 1,2-bis[4-(3-aminophenoxy)phenyl]ethane, bis[4-(3-aminophenoxy)phenyl]sulfoxide, 4,4'-bis[3-(4-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[3-(3-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenyl sulfone, bis[4-{4-(4-aminophenoxy)phenoxy}phenyl]sulfone, 1,4-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl] Benzene, 1,3-bis[4-(4-amino-6-trifluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-fluorophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-methylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-cyanophenoxy)-α,α-dimethylbenzyl]benzene, 3,3'-diamino-4,4'-di Phenoxybenzophenone, 4,4'-diamino-5,5'-diphenoxybenzophenone, 3,4'-diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino- 5,5'-Dibiphenoxybenzophenone, 3,4'-Diamino-4,5'-Dibiphenoxybenzophenone, 3,3'-Diamino-4-Biphenoxybenzophenone, 4,4'-Diamino-5-Biphenoxybenzophenone, 3,4'-Diamino-4-Biphenoxybenzophenone, 3,4'-Diamino-5'-Biphenoxybenzophenone, 1,3-Bis(3-amino-4-phenoxybenzoyl)benzene, 1,4-Bis(3-amino-4-phenoxybenzoyl) Benzene, 1,3-bis(4-amino-5-phenoxybenzoyl)benzene, 1,4-bis(4-amino-5-phenoxybenzoyl)benzene, 1,3-bis(3-amino-4-biphenoxybenzoyl)benzene, 1,4-bis(3-amino-4-biphenoxybenzoyl)benzene, 1,3-bis(4-amino-5-biphenoxybenzoyl)benzene, 1,4-bis(4-amino-5-biphenoxybenzoyl)benzene, 2,6-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzonitrile, and aromatic diamines in which some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine have been substituted with halogen atoms, alkyl or alkoxy groups having 1 to 3 carbon atoms, cyano groups, or halogenated alkyl or alkoxy groups having 1 to 3 carbon atoms in which some or all of the hydrogen atoms of the alkyl or alkoxy groups have been substituted with halogen atoms.

[0108] Examples of the aliphatic diamines include 1,2-diaminoethane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, and 1,8-diaminoethane. Examples of the aliphatic diamines include 1,4-diaminocyclohexane and 4,4'-methylenebis(2,6-dimethylcyclohexylamine). The total amount of diamines other than aromatic diamines (aliphatic diamines) is preferably 20% by mass or less of all diamines, more preferably 10% by mass or less, and even more preferably 5% by mass or less. In other words, aromatic diamines preferably account for 80% by mass or more of all diamines, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0109] As the solvent, the same solvents as those explained in the section on the first resin composition solution can be used.

[0110] [Film before cutting] The pre-cut film according to this embodiment is The center and and both end portions formed continuously from the central portion at both ends of the central portion. and the central portion is made of a first resin composition containing a first resin and a filler, and the content of the filler is 0.1% by mass or more and 50% by mass or less with respect to the first resin; the two end portions are made of a second resin composition containing a second resin, and the second resin composition does not contain a filler, or even if it contains a filler, the content of the filler is less than that of the first resin composition and is 2 mass % or less relative to the second resin; The tear strength at both ends is greater than the tear strength at the center.

[0111] The pre-cut film can be obtained by the steps A to C of the resin film manufacturing method according to this embodiment. Here, the "first resin composition" refers to the composition (sheet-like material) obtained after drying the first resin composition solution in step C, and the "second resin composition" refers to the composition (sheet-like material) obtained after drying the second resin composition solution in step C.

[0112] The CTE of the central portion of the uncut film is preferably 5 ppm / K or more and 50 ppm / K or less. In order to improve the heat resistance of the resin film, it is preferably 45 ppm / K or less, more preferably 40 ppm / K or less, and even more preferably 35 ppm / K or less. From an industrial perspective, it may be 6 ppm / K or more, or even 7 ppm / K or more.

[0113] The total light transmittance of the central portion of the film before cutting is preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more. There is no particular upper limit to the total light transmittance, but from an industrial perspective, it may be 99% or less, or even 98% or less.

[0114] The haze ratio of the central portion of the film before cutting is preferably 5% or less, more preferably 3% or less, and even more preferably 1% or less. There is no particular lower limit to the haze ratio, but from an industrial perspective, it may be 0.01% or more, and even 0.1% or more is acceptable.

[0115] The YI (yellowness index) of the central part of the film before cutting is preferably 10 or less, more preferably 7 or less, and even more preferably 5 or less. The lower limit of the YI (yellowness index) is not particularly limited, but may be 1 or more from an industrial standpoint.

[0116] The static friction coefficient of the central portion of the film before cutting is preferably 2.5 or less, more preferably 2 or less, and even more preferably 1.5 or less. There is no particular lower limit to the static friction coefficient, but industrially it may be 0.01 or more, or even 0.1 or more.

[0117] The tear strength of the central portion is preferably in the range of 0.1 to 15 N / mm, more preferably in the range of 1 to 10 N / mm, as measured by the following method.

[0118] The tear strength at both ends is preferably within a range of 0.5 to 30 N / mm, more preferably within a range of 1 to 20 N / mm, as measured by the following method. The tear strength of the both end portions is preferably more than 1 time and not more than 10 times, more preferably more than 1.1 times and not more than 5 times, the tear strength of the central portion.

[0119] <Method for measuring tear strength> According to the trouser tearing method described in JIS K7128-1, the test speed is 200 mm / min, and the tear strength is the average value of the remaining 50 mm excluding the 20 mm at the start of tearing and the 5 mm before the end of tearing. [Tear strength (N / mm)] = [Tear force of test piece (N)] / [Thickness of test piece (d)]

[0120] The width of both ends (the width of each end) is not particularly limited as long as it can be gripped by a conventionally known tenter-type conveying device, and is generally 5 mm or more, more preferably 10 mm or more. The upper limit of the width is not particularly limited, and for example, the sum of both ends may be 50% or less of the total width of the film, more preferably 30% or less, and even more preferably 10% or less. The width of both ends (the width of each end) is not particularly limited as long as it can be gripped by a conventionally known tenter-type conveying device, and for example, the sum of the widths of both ends is 0.1% or more of the total width of the film, more preferably 0.5% or more, and even more preferably 1% or more. The upper limit of the width is not particularly limited, and for example, the sum of the widths of both ends may be 50% or less of the total width of the film, more preferably 30% or less, and even more preferably 10% or less.

[0121] The uncut film according to this embodiment has been described above. [Example]

[0122] The present invention will be described in detail below using examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0123] Synthesis Example 1 (Preparation of Polyamic Acid Solution A) After replacing the atmosphere inside a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer with nitrogen, 1,470.8 parts by mass of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 775.6 parts by mass of 4,4'-oxydiphthalic acid (ODPA), 3,202.4 parts by mass of 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl (TFMB), 5,448.8 parts by mass of dimethylacetamide-dispersed silica sol (DMAc-ST manufactured by Nissan Chemical Industries, Ltd.), and 21,795 parts by mass of N,N-dimethylacetamide were charged into the reaction vessel under a nitrogen atmosphere and dissolved. The mixture was then stirred at room temperature for 24 hours to obtain polyamic acid solution A with a solids content of 17.2% by mass and a reduced viscosity of 4.5 dl / g.

[0124] [Synthesis Example 2 (Preparation of Polyimide Solution B)] A reaction vessel equipped with a nitrogen inlet tube, thermometer, and stirrer was purged with nitrogen. Then, 551 parts by weight of N,N-dimethylacetamide (DMAC) and 64.1 parts by weight of 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl (TFMB) were added to the reaction vessel under a nitrogen atmosphere and stirred to dissolve the TFMB in the DMAC. Next, 44.4 parts by weight of 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride (6FDA) and 29.4 parts by weight of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) were added to the reaction vessel over a 10-minute period under a nitrogen stream while stirring. The temperature was maintained at 20-40°C while stirring for 6 hours to allow polymerization, resulting in a viscous polyamic acid solution. Next, 410 parts by mass of DMAC was added to the obtained polyamic acid solution to dilute it, and then 25.83 parts by mass of isoquinoline was added as an imidization accelerator. The polyamic acid solution was stirred while maintaining the temperature in the range of 30 to 40°C, and 122.5 parts by mass of acetic anhydride was slowly added dropwise as an imidization agent over a period of about 10 minutes. Thereafter, the liquid temperature was further maintained at 30 to 40°C and stirring was continued for 12 hours to carry out a chemical imidization reaction, thereby obtaining a polyimide solution. Next, 1,000 parts by mass of the resulting polyimide solution containing the imidization agent and imidization accelerator was transferred to a reaction vessel equipped with a stirrer and impeller. While stirring at 120 rpm and maintaining the temperature at 15-25°C, 1,500 parts by mass of methanol was added dropwise at a rate of 10 g / min. After approximately 800 parts by mass of methanol had been added, the polyimide solution became cloudy, confirming the precipitation of powdery polyimide. The entire 1,500 parts by mass of methanol was then added to complete the precipitation of polyimide. The contents of the reaction vessel were then filtered using a suction filter, followed by washing and filtration with another 1,000 parts by mass of methanol. 50 parts by mass of the filtered polyimide powder was then dried in a dryer equipped with a local exhaust system at 50°C for 24 hours and then at 260°C for 2 hours to remove the remaining volatile components, yielding a polyimide powder. The reduced viscosity of the resulting polyimide powder was 2.1 dl / g. Next, 42 parts by mass of the obtained polyimide powder was dissolved in 168 parts by mass of DMAC to obtain a polyimide solution B with a solid content of 20% by mass.

[0125] [Synthesis Example 3 (Preparation of Polyimide Solution C)] A reaction vessel equipped with a nitrogen inlet tube, Dean-Stark apparatus, reflux condenser, thermometer, and stirrer was charged with 124.15 parts by mass of 4,4'-diaminodiphenyl sulfone (4,4'-DDS), 124.15 parts by mass of 3,3'-diaminodiphenyl sulfone (3,3'-DDS), and 750 parts by mass of gamma-butyrolactone (GBL) while introducing nitrogen gas. Subsequently, 248.18 parts by mass of 4,4'-oxydiphthalic acid dihydrate (ODPA), 58.8 parts by mass of biphenyltetracarboxylic dianhydride, 335 parts by mass of GBL, and 390 parts by mass of toluene were added at room temperature. The internal temperature was then raised to 160 °C and refluxed at 160 °C for 1 hour to allow imidization. After imidization was complete, the temperature was raised to 180 °C, and the reaction was continued while the toluene was removed. After 12 hours of reaction, the oil bath was removed, the temperature was returned to room temperature, and 1149 parts by mass of GBL was added so that the solid content became 20% by mass, to obtain a polyimide solution C having a reduced viscosity of 0.6 dl / g.

[0126] Synthesis Example 4 (Preparation of Polyamic Acid Solution D) After replacing the atmosphere inside a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer with nitrogen, 196.1 parts by mass of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 227.3 parts by mass of 4-amino-N-(4-aminophenyl)benzamide (DABAN), and 1694 parts by mass of N,N-dimethylacetamide were charged into the reaction vessel under a nitrogen atmosphere and dissolved, followed by stirring at room temperature for 24 hours to obtain polyamic acid solution D with a solids content of 20% by mass and a reduced viscosity of 4.5 dl / g.

[0127] Synthesis Example 5 (Preparation of Polyamideimide Solution E) After replacing the atmosphere in a reaction vessel equipped with a nitrogen inlet tube, a thermometer, and a stirrer with nitrogen, 153.7 parts by mass of trimellitic anhydride, 256.4 parts by mass of O-tolidine diisocyanate, 29.4 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 32.2 parts by mass of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 1 part by mass of triethylenediamine, and 1671 parts by mass of N-methyl-2-pyrrolidone were added, and the mixture was heated to 130°C over 1 hour with stirring, and then reacted at 130°C for a further 5 hours to obtain a polyamideimide resin solution E having a reduced viscosity of 1.6 dl / g.

[0128] [Reduced viscosity] The reduced viscosities (dL / g) of the prepared polyamic acid solutions A and D, polyimide solutions B and C, and polyamide-imide acid solution E were measured at 30°C using an Ubbelohse viscometer by dissolving 0.02 g of each sample in 10 mL of a mixed solvent (phenol / tetrachloroethane = 60 / 40 (mass ratio)).

[0129] Example 1 Polyamic acid solution A (Synthesis Example 1 (PAA-A)) was prepared. Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm, active ingredient 20% by mass, manufactured by Nissan Chemical Industries) was added to a portion of this solution while stirring the polyamic acid solution A so that the active ingredient was 10% by mass relative to the resin. Stirring was then maintained for 6 hours to obtain polyamic acid solution A-1 (PAA-A1). Using the comma coater shown in Figures 1 and 2, polyamic acid solution A-1 was applied to a 500 mm wide central portion of a support PET film (A4100 manufactured by Toyobo Co., Ltd.) with the clearance adjusted to give a final film thickness of 22 μm, and polyamic acid solution A was simultaneously applied to each end of the support in a 50 mm wide portion. At this time, side plates with a width of 10 mm were used. The polyamic acid film was then dried at 100-110°C for 10 minutes, and after drying, it was wound up on a 6-inch ABS core together with the PET film to obtain a polyamic acid film roll. The polyamic acid film and the PET film were unwound from the obtained polyamic acid film roll, and the self-supporting polyamic acid film was peeled off from the PET film to obtain a polyamic acid film. The resulting polyamic acid film was passed through a pin tenter with a pin sheet arranged so that the pin spacing was constant when the pin sheets were lined up, and the film edges were held by inserting them into the pins. The pin sheet spacing was adjusted to prevent film breakage and unnecessary sagging, and the film was conveyed so that the final pin sheet spacing was 520 mm. The film was heated at 200°C for 3 minutes in the first stage, 250°C for 3 minutes in the second stage, 300°C for 3 minutes in the third stage, and 350°C for 3 minutes in the fourth stage to promote the imidization reaction. The film was then cooled to room temperature over 2 minutes, and the edges of the film formed with polyamic acid solution A were slit to obtain only the center portion, yielding a polyimide film 22 μm thick and 480 mm wide.

[0130] Example 2 Polyamic acid solution A (Synthesis Example 1) was prepared. Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to a portion of this polyamic acid solution A while stirring, so that the active ingredient was 5% by mass relative to the resin. Stirring was then maintained for 6 hours, yielding polyamic acid solution A-2 (PAA-A2). Next, Snowtex (registered trademark) DMAc-ST-ZL (DMAc dispersion of silica with an average particle size of 80 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to the remaining polyamic acid solution A while stirring, so that the active ingredient was 0.5% by mass relative to the resin. Stirring was then maintained for 6 hours, yielding polyamic acid solution A-3 (PAA-A3). A polyimide film having a thickness of 10 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that polyamic acid solution A-2 was applied instead of polyamic acid solution A-1, and polyamic acid solution A-3 was applied instead of polyamic acid solution A, with the clearance adjusted so that the final film thickness would be 10 μm.

[0131] Example 3 Polyamic acid solution A (Synthesis Example 1) was prepared. To a portion of this solution, Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm, active ingredient 20% by mass; Nissan Chemical Industries) and Snowtex (registered trademark) DMAc-ST-ZL (DMAc dispersion of silica with an average particle size of 80 nm, active ingredient 20% by mass; Nissan Chemical Industries) were added with stirring to achieve active ingredient concentrations of 0.3% and 0.2% by mass, respectively, relative to the resin. Stirring was then maintained for 6 hours to obtain polyamic acid solution A-4 (PAA-A4). A polyimide film having a thickness of 35 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that polyamic acid solution A-4 was applied instead of polyamic acid solution A-1 while adjusting the clearance so that the final film thickness would be 35 μm.

[0132] Example 4 Polyimide solution B (Synthesis Example 2 (PI-B)) was prepared. Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient 20% by mass; Nissan Chemical Industries) was added to a portion of this solution while stirring polyimide solution B so that the active ingredient content relative to the resin was 10% by mass. Stirring was then maintained for 6 hours to obtain polyimide solution B-1 (PI-B1). A polyimide film having a thickness of 115 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that polyimide solution B-1 was applied instead of polyamic acid solution A-1, and polyimide solution B was applied instead of polyamic acid solution A, with the clearance adjusted so that the final film thickness would be 115 μm.

[0133] Example 5 Polyimide solution C (Synthesis Example 3 (PI-C)) was prepared. Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to a portion of this solution while stirring polyimide solution B so that the active ingredient content relative to the resin was 10% by mass. Stirring was then maintained for 6 hours to obtain polyimide solution C-1 (PI-C1). Polyimide solution C was applied to both ends of a mirror-finished stainless steel belt using the comma coater shown in Figures 7 and 8, and then polyimide solution C-1 was applied to the center using a T-die, adjusting the clearance to give a final film thickness of 25 μm. At this time, the width of the center was 1000 mm, and the widths of both ends were 50 mm. Next, it was dried at 100 to 110°C for 10 minutes, and after drying, it was peeled off from the support to obtain a self-supporting polyimide film. The resulting uncut film was passed through a pin tenter with a pin sheet arranged so that the pin spacing was constant when the pins were lined up. The film edges were clamped by inserting them into the pins, and the pin sheet spacing was adjusted to prevent film breakage and unnecessary sagging. The film was then conveyed so that the final pin sheet spacing was 1000 mm. The film was heated at 200°C for 3 minutes in the first stage, 250°C for 3 minutes in the second stage, 300°C for 3 minutes in the third stage, and 350°C for 3 minutes in the fourth stage to promote the imidization reaction. The film was then cooled to room temperature over 2 minutes. The edges of the film formed with polyimide solution B were slit to leave only the center portion, which was then continuously wound into a roll around a 3-inch ABS resin core to obtain a 25 μm thick, 980 mm wide, and 500 m long polyimide film.

[0134] Example 6 Polyimide solution A (Synthesis Example 1) and polyamic acid solution D (Synthesis Example 4 (PAA-D)) were prepared. Snowtex (registered trademark) DMAc-ST-ZL (DMAc dispersion of silica with an average particle size of 80 nm; active ingredient: 20% by mass; manufactured by Nissan Chemical Industries) was added to a portion of this polyamic acid solution A while stirring, so that the active ingredient content was 0.1% by mass relative to the resin. Stirring was then maintained for 6 hours to obtain polyimide solution A-5 (PAA-A5). Next, Snowtex (registered trademark) DMAc-ST-ZL (DMAc dispersion of silica with an average particle size of 80 nm; active ingredient: 20% by mass; manufactured by Nissan Chemical Industries) was added to a portion of polyamic acid solution D while stirring, so that the active ingredient content was 0.5% by mass relative to the resin. Stirring was then maintained for 6 hours to obtain polyimide solution D-1 (PAA-D1). Using the T-die shown in Figures 9 and 10, polyimide solution A-5 was applied to both ends of a mirror-finished stainless steel belt, and polyamic acid solution D-1 was applied to the center using a T-die with the clearance adjusted to a final film thickness of 26 μm. At this time, the width of the center was 1000 mm, and the width of each end was 50 mm. Next, it was dried at 100 to 110°C for 10 minutes, and after drying, it was peeled off from the support to obtain a self-supporting polyamic acid film. The resulting uncut film was passed through a pin tenter with a pin sheet arranged so that the pin spacing was constant when the pins were lined up. The film edges were clamped by inserting them into the pins, and the pin sheet spacing was adjusted to prevent film breakage and unnecessary slack. The film was conveyed so that the final pin sheet spacing was 520 mm. The film was heated at 200°C for 3 minutes in the first stage, 250°C for 3 minutes in the second stage, 300°C for 3 minutes in the third stage, and 350°C for 3 minutes in the fourth stage to promote the imidization reaction. The film was then cooled to room temperature over 2 minutes. The edges of the film formed with polyimide solution A-5 were slit to leave only the center portion, which was then continuously wound into a roll around a 3-inch ABS resin core to obtain a 26 μm thick, 980 mm wide, and 500 m long polyimide film.

[0135] Example 7 Polyamideimide solution E (Synthesis Example 5 (PAI-E)) was prepared. Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient 20% by mass: Nissan Chemical Industries) was added to a portion of this polyamideimide solution E while stirring the polyamideimide solution E so that the active ingredient was 10% by mass relative to the resin. Stirring was then maintained for 6 hours to obtain polyamideimide solution E-1 (PAI-E1). A polyimide film having a thickness of 42 μm and a width of 480 mm was obtained in the same manner as in Example 6, except that polyamideimide solution E was applied instead of polyimide solution A-5 while adjusting the clearance so that the final film thickness would be 42 μm, and polyamideimide solution E-1 was used instead of polyamic acid solution D-1.

[0136] Example 8 Polyimide solution B (Synthesis Example 2) and polyamic acid solution A (Synthesis Example 1) were prepared. Snowtex (registered trademark) DMAc-ST-ZL (DMAc dispersion of silica with an average particle size of 80 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to polyimide solution B with stirring, so that the active ingredient content was 0.5% by mass relative to the resin. Stirring was then maintained for 6 hours to obtain polyimide solution B-2 (PI-B2). Next, Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to polyimide solution A with stirring, so that the active ingredient content was 10% by mass relative to the resin. Stirring was then maintained for 6 hours to obtain polyimide solution A-1 (PI-A1). A polyimide film having a thickness of 25 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that polyimide solution B-2 was applied instead of polyamic acid solution A while adjusting the clearance so that the final film thickness would be 25 μm.

[0137] Example 9 A polyimide film having a thickness of 75 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that a clip tenter, which holds both ends with clips, was used instead of a pin tenter having a pin sheet in which pins were arranged so that the pin spacing was constant when the pin sheet was lined up, and polyamic acid solution A was applied while adjusting the clearance so that the final film thickness would be 75 μm.

[0138] Example 10 Polyimide solution B (Synthesis Example 2) and polyamideimide solution E (Synthesis Example 5) were prepared. Of these, Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient 20% by mass: Nissan Chemical Industries) was added to polyamideimide solution E while stirring so that the active ingredient was 10% by mass relative to the resin. Stirring was then maintained for 6 hours to obtain polyamideimide solution E-1 (PAI-E1). A polyamideimide film having a thickness of 25 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that polyimide solution B was applied instead of polyamic acid solution A, and polyamideimide solution E-1 was applied instead of polyamic acid solution A-1, with the clearance adjusted so that the final film thickness would be 25 μm.

[0139] Example 11 A polyimide film having a thickness of 22 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that instead of Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient: 20% by mass: Nissan Chemical Industries) being added so that the active ingredient was 10% by mass relative to the resin, titanium oxide (average particle size 200 nm) was added so that the active ingredient was 0.75% by mass relative to the resin (PAA-A6).

[0140] Example 12 Polyimide solution B (Synthesis Example 2) and polyamideimide solution E (Synthesis Example 5) were prepared. Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to polyimide solution B with stirring, so that the active ingredient content relative to the resin was 10%. Stirring was then maintained for 6 hours to obtain polyimide solution B-1. Next, Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to polyamideimide solution E with stirring, so that the active ingredient content relative to the resin was 1%. Stirring was then maintained for 6 hours to obtain polyamideimide solution E-2 (PAI-E2). A polyamideimide film having a thickness of 25 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that polyamideimide solution E-2 was applied instead of polyamic acid solution A, and polyimide solution B-1 was applied instead of polyamic acid solution A-1, with the clearance adjusted so that the final film thickness would be 25 μm.

[0141] (Comparative Example 1) Polyamic acid solution A (Synthesis Example 1) was prepared. Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to a portion of this solution while stirring, so that the active ingredient was 10% by mass relative to the resin. Stirring was then maintained for 6 hours, yielding polyamic acid solution A-1. Next, Snowtex (registered trademark) DMAc-ST (DMAc dispersion of silica with an average particle size of 10 nm; active ingredient: 20% by mass; Nissan Chemical Industries) was added to the remaining polyamic acid solution A while stirring, so that the active ingredient was 5% by mass relative to the resin. Stirring was then maintained for 6 hours, yielding polyamic acid solution A-2. Using the comma coater shown in Figures 1 and 2, polyamic acid solution A-1 was applied to a 500 mm wide central portion of a support PET film (A4100 manufactured by Toyobo Co., Ltd.) with the clearance adjusted to a final film thickness of 22 μm, and polyamic acid solution A-2 was simultaneously applied to each end of the support in a 50 mm wide area. Side plates with a width of 10 mm were used. The polyamic acid film was then dried at 100-110°C for 10 minutes, and after drying, it was wound up on a 6-inch ABS core together with the PET film to obtain a polyamic acid film roll. The polyamic acid film and the PET film were unwound from the obtained polyamic acid film roll, and the self-supporting polyamic acid film was peeled off from the PET film to obtain a polyamic acid film. The resulting polyamic acid film was passed through a pin tenter with a pin sheet arranged so that the pin spacing was constant when the pin sheets were lined up. The film edges were clamped by inserting them into the pins. The pin sheet spacing was adjusted to prevent film breakage and unnecessary slack. The film was conveyed so that the final pin sheet spacing was 520 mm. The film was heated at 200°C for 3 minutes in the first stage, 250°C for 3 minutes in the second stage, 300°C for 3 minutes in the third stage, and 350°C for 3 minutes in the fourth stage to promote the imidization reaction. The film was then cooled to room temperature over 2 minutes. Attempts to remove the film from the pins resulted in breakage at the pin holes, making it impossible to obtain a film.

[0142] (Comparative Example 2) Polyimide solution B (Synthesis Example 2) was prepared. A polyimide film with a thickness of 25 μm and a width of 480 mm was obtained in the same manner as in Example 1, except that polyimide solution B was applied by adjusting the clearance so that the final film thickness was 25 μm instead of polyamic acid solution A and polyamic acid solution A-1.

[0143] (Comparative Example 3) Polyimide solution A (Synthesis Example 2) was prepared. Snowtex (registered trademark) DMAc-ST (a DMAc dispersion of silica with an average particle size of 10 nm. Active ingredient: 20% by mass, Nissan Chemical Industries, Ltd.) was added to a part of this solution while stirring the polyamic acid solution A so that the active ingredient was 60% by mass based on the resin. Then, stirring was maintained for 6 hours to obtain polyamic acid solution A-7 (PAA-A7). An attempt was made to produce a film in the same manner as in Example 1, except that polyimide solution A-7 was applied by adjusting the clearance so that the final film thickness was 25 μm instead of polyamic acid solution A-1. However, the film broke from the hole part through which the pin was passed and a film could not be obtained.

[0144] (Comparative Example 4) Polyimide solution A (Synthesis Example 2) was prepared. Snowtex (registered trademark) DMAc-ST (a DMAc dispersion of silica with an average particle size of 10 nm. Active ingredient: 20% by mass, Nissan Chemical Industries, Ltd.) was added to this polyamic acid solution A while stirring the polyamic acid solution A so that the active ingredient was 10% by mass based on the resin. Then, stirring was maintained for 6 hours to obtain polyamic acid solution A-1. An attempt was made to produce a film in the same manner as in Example 1, except that polyimide solution A-1 was applied by adjusting the clearance so that the final film thickness was 25 μm instead of polyamic acid solution A. However, the film broke from the hole part through which the pin was passed and a film could not be obtained.

[0145] <CTE (Coefficient of Thermal Expansion in the Linear Direction)> The film was stretched and shrunk under the following conditions in the flow direction (MD direction) and width direction (TD direction) during coating, and the stretch / shrink ratio / temperature at intervals of 15°C such as 30°C to 45°C and 45°C to 60°C was measured. This measurement was carried out up to 300°C, and the average value of all measurement values was calculated as the CTE. Furthermore, the average value of the measurement values in the MD direction and TD direction was obtained. Equipment name; TMA4000S manufactured by MAC Science Sample length; 20 mm Sample width; 2 mm Temperature at the start of heating; 25°C Temperature at the end of heating; 300°C Heating rate; 5°C / min Atmosphere; Argon

[0146] <Total light transmittance> The total light transmittance of the film was measured using a HAZEMETER (NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.). A D65 lamp was used as the light source. In addition, the same measurement was carried out 3 times, and the arithmetic mean value was adopted.

[0147] <Haze ratio> The haze of the film was measured using a HAZEMETER (NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.). A D65 lamp was used as the light source. In addition, the same measurement was carried out 3 times, and the arithmetic mean value was adopted.

[0148] <YI (Yellowness)> Using a colorimeter (ZE6000, manufactured by Nippon Denshoku Industries Co., Ltd.) and a C2 light source, the tristimulus values XYZ values of the film were measured according to ASTM D1925, and YI (yellowness) was calculated by the following formula. In addition, the same measurement was carried out 3 times, and the arithmetic mean value was adopted. YI = 100×(1.28X - 1.06Z) / Y

[0149] <Coefficient of static friction> In accordance with JIS K-7125 (1999), a tensile tester (A&D Tensilon RTG-1210) was used to measure the coefficient of static friction when the inner and outer surfaces of the film were joined together under an environment of 23°C and 65% RH. The weight of the thread (weight) around which the upper film was wrapped was 1.5 kg, and the size of the base area of ​​the thread was 39.7 mm. 2 The pulling speed during the friction measurement was 200 mm / min.

[0150] <Film thickness measurement> The thickness of the film was measured using a micrometer (Militron 1245D, manufactured by Fineruf Co., Ltd.).

[0151] <Tear strength> The tear strength of the center and both ends of the films obtained in the examples and comparative examples before cutting was measured. Specifically, the tear strength was determined according to the trouser tearing method described in JIS K7128-1, with a test speed of 200 mm / min. The tear strength was calculated by averaging the remaining 50 mm, excluding the 20 mm at the start of tearing and the 5 mm before the end of tearing. The results are shown in Table 1. [Tear strength (N / mm)] = [Tear stress of test piece (N)] / [Test piece thickness (d)]

[0152] The tear strength obtained here (the tear strength listed in Table 1) is the tear strength of the polyimide film (resin film) after step G. If the tear strength of the portion of the polyimide film after step G formed from the second resin composition solution is greater than the tear strength of the portion formed from the first resin composition solution, then naturally, the tear strength of the portion of the pre-cut film after step C and before step F will also be greater than the tear strength of the portion formed from the first resin composition solution. The tear strength of the central part of the uncut film after step C and before step F of Example 8 was measured by the same method as above and was found to be 1.8 N / mm. This also clearly shows that if the tear strength of the part formed from the second resin composition solution in the polyimide film after step G is greater than the tear strength of the part formed from the first resin composition solution, then the tear strength of the part formed from the second resin composition solution in the uncut film after step C and before step F will also be greater than the tear strength of the part formed from the first resin composition solution.

[0153] [Table 1]

[0154] In the polyimide films of Examples 1 to 12, the tear strength of the portion formed from the second resin composition solution was greater than the tear strength of the portion formed from the first resin composition solution, so there was no breakage or deformation after heat treatment. Furthermore, the CTE and transparency were also good. On the other hand, the pre-cut films of Comparative Examples 1 to 4 were films formed from a single resin composition solution with low tear strength, so tears occurred at the hole where the pin was inserted, and no film could be obtained. [Explanation of symbols]

[0155] 10, 30, 40, 50 coating device 12 Backup Roll 14 Comma Roll 16 (16a, 16b, 16c) Coating liquid storage section 18(18a, 18b, 18c, 18d) Side plate 20 Backplate 22 Gap 60 Support 62 (62a, 62b, 62c) Coating liquid 64(64a, 64b, 64c) Coating film

Claims

1. Step A: applying a first resin composition solution to a central portion of a support; Step B: applying a second resin composition solution to both end portions adjacent to the central portion; A step C of drying the first resin composition solution and the second resin composition solution to obtain a pre-cut film; Step D: peeling the pre-cut film from the support; a step E of holding both end portions of the pre-cut film by a tenter-type conveying device after the step D; a step F of conveying the uncut film while holding both end portions of the uncut film; and After the step F, a step G is performed in which a portion formed from the second resin composition solution is removed from the pre-cut film to obtain a resin film. and the first resin composition solution contains a first resin and a filler, and the content of the filler is 0.1% by mass or more and 50% by mass or less with respect to the first resin; the second resin composition solution contains a second resin and does not contain a filler, or if it contains a filler, the content of the filler is less than that of the first resin composition solution and is 2 mass% or less relative to the second resin; A method for producing a resin film, characterized in that after step C and before step F, the pre-cut film has a tear strength of the portion formed from the second resin composition solution that is greater than the tear strength of the portion formed from the first resin composition solution.

2. 2. The method for producing a resin film according to claim 1, wherein the resin film has a CTE of 5 ppm / K or more and 50 ppm / K or less.

3. 3. The method for producing a resin film according to claim 1, wherein step E is a step of holding both end portions of the uncut film with pins of a pin tenter type conveying device.

4. 4. The method for producing a resin film according to claim 1, wherein the resin film is a polyimide-based resin film.

5. 5. The method for producing a resin film according to claim 1, wherein the support is a polymer film.

6. 6. The method for producing a resin film according to claim 1, wherein the filler is silica.

7. The center and and both end portions formed continuously from the central portion at both ends of the central portion. and the central portion is composed of a first resin composition containing a first resin and a filler, and a content of the filler is 0.1% by mass or more and 50% by mass or less with respect to the first resin; the two end portions are made of a second resin composition containing a second resin, and the second resin composition does not contain a filler, or even if it contains a filler, the content of the filler is less than that of the first resin composition and is 2 mass % or less relative to the second resin; A pre-cut film characterized in that the tear strength at both ends is greater than the tear strength at the center.

8. The uncut film according to claim 7, wherein the first resin is a polyimide resin.

9. 9. The film before cutting according to claim 7 or 8, wherein the CTE of the central portion is 5 ppm or more and 50 ppm / K or less.

10. The pre-cut film according to any one of claims 7 to 9, characterized in that the filler is silica.

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