Film material, structure, and wiring board

Abstract

The present invention addresses the problem of providing a film material having excellent handleability at room temperature, having sufficient heat resistance, and capable of thermocompression bonding.　The present invention is a film material having a first surface S1 and a second surface S2 on the back side thereof. The film material is a resin layer that includes one or more thermocompression bonding layers. The thermocompression bonding layer is non-adhesive at 25°C, has thermocompression bonding properties at a higher temperature, by at least 10°C, than the glass transition temperature of the thermocompression bonding layer, and does not melt at 250°C or lower. The outermost surface layers of both the first surface side and the second surface side of the film material are the thermocompression bonding layers.

Description

Film materials, structures and wiring boards

[0001] The present disclosure relates to a film material, a structure, and a wiring board.

[0002] Generally, heat-sealable films such as polyethylene films and polyethylene terephthalate films are used as adhesives for forming packaging bodies.

[0003] In devices that require high heat resistance, such as electronic component devices, resin layers that adhere to other components are often formed of thermosetting adhesive films. For example, in a wiring board in which multiple glass substrates are stacked and a resin layer is provided between adjacent glass substrates, the resin layer may be formed of a thermosetting adhesive that has adhesive properties to the glass substrates, etc. (Patent Documents 1 and 2).

[0004] JP 2017-107934 A JP 2018-148126 A

[0005] Thermosetting adhesive films have tackiness before curing at room temperature and are prone to deformation, so some care must be taken when handling them at room temperature. Therefore, it is common to protect both sides of the adhesive film with a protective film or the like until use, and the adhesive film is often stored refrigerated. Furthermore, a curing process is required to ensure adhesive strength and heat resistance. On the other hand, with conventional heat-sealing films, the application of a protective film is not necessarily required, and a curing process is also not required, but heat resistance may be insufficient depending on the application.

[0006] The present disclosure relates to a film material that is easy to handle at room temperature, has sufficient heat resistance, and is capable of being thermocompression bonded.

[0007] The present disclosure includes the following: [1] A film material having a first surface and a second surface on the reverse side thereof, the film material including one or more thermocompression layers, the thermocompression layers being resin layers that are non-adhesive at 25°C, have thermocompression bondability at a temperature 10°C or higher than the glass transition temperature of the thermocompression layers, and do not melt at 250°C or lower, the thermocompression layers being outermost layers on both the first surface side and the second surface side. [2] The film material according to [1], wherein the thermocompression layers contain a polyamideimide resin. [3] The film material according to [1] or [2], wherein the thermocompression layers contain a polycarbonate resin, a polyethersulfone resin, or a polyarylate resin. [4] The film material according to any one of [1] to [3], wherein the content of an organic solvent in the thermocompression layers is less than 10 ppm by mass based on the mass of the thermocompression layers. [5] A wound body comprising: the film material according to any one of [1] to [4]; and a winding core, wherein the film material is wound around the winding core with the first surface and the second surface directly contacting each other. [6] A structure comprising: a plurality of sheet-like glass substrates; and an adhesive layer, wherein the plurality of glass substrates are stacked in the thickness direction of the structure, the adhesive layer is provided between adjacent glass substrates, and at least a portion of the adhesive layer is the film material according to any one of [1] to [4]. [7] A wiring board comprising: a plurality of sheet-like glass substrates; an adhesive layer; and a wiring layer, wherein the plurality of glass substrates are stacked in the thickness direction of the structure, the adhesive layer and the wiring layer are provided between adjacent glass substrates, and at least a portion of the adhesive layer is the film material according to any one of [1] to [4].

[0008] A film material can be provided that is easy to handle at room temperature, has sufficient heat resistance, and is capable of being thermocompression bonded.

[0009] 1 is a cross-sectional view showing an example of a film material; 2 is a cross-sectional view showing an example of a film material; 3 is a perspective view showing an example of a wound body; 4 is a cross-sectional view showing an example of a wiring board (structure);

[0010] The present invention is not limited to the following examples.

[0011] Fig. 1 is a cross-sectional view showing an example of a film material. The film material 10 shown in Fig. 1 is a single-layer film having a first surface S1 and a second surface S2 on the reverse side thereof, and consisting of one thermocompression layer 1. In other words, the outermost layer of the film material 10 on both the first surface S1 side and the second surface S2 side is the thermocompression layer 1.

[0012] The thermocompression layer 1 is a resin layer that is non-adhesive at 25°C and has thermocompression bondability at a temperature that is at least 10°C higher than the glass transition temperature of the thermocompression layer 1. The film material 10 can be bonded to another member by thermocompression bonding, in which the film material 10 is heated to a temperature that is at least 10°C higher than the glass transition temperature of the thermocompression layer 1 and pressed against the other member. In addition, because the thermocompression layer 1 located at the outermost layer is non-adhesive at 25°C, the film material 10 can be appropriately stored alone at room temperature in the form of a roll or the like, without the need for an additional member such as a protective film.

[0013] A thermocompression layer 1 that is non-adhesive at 25° C. does not substantially adhere to other members when pressure-bonded to them at 25° C. For example, a film material is pressure-bonded to a glass plate (inorganic glass plate) at 25° C. for 10 seconds while applying a pressure of 6 MPa to the film material so that the glass plate and the thermocompression layer are in contact with each other, and then a peel test is conducted at 25° C. in which the film material is pulled in a direction 90° relative to the surface of the glass plate and peeled off. If the 90° peel strength measured by this peel test is 5 N / m or less, the thermocompression layer can be considered to be non-adhesive at 25° C. In the present disclosure, the pulling speed in the peel test can be 50 mm / min.

[0014] The thermocompression layer 1 has thermocompression bonding properties such that it adheres to other members when heated to a temperature 10°C or more higher than the glass transition temperature of the thermocompression layer 1 and pressure-bonded to other members. For example, a film material is pressure-bonded to a glass plate (inorganic glass plate) at a temperature 10°C or more higher than the glass transition temperature of the thermocompression layer 1 for 10 seconds while applying a pressure of 6 MPa to the film material so that the glass plate and the thermocompression layer are in contact with each other. Then, a peel test is conducted at 200°C in which the film material is pulled in a direction 90° relative to the surface of the glass plate and peeled off. If the 90° peel strength measured by this peel test is 100 N / m or more, the thermocompression layer can be considered to have thermocompression bonding properties at a temperature 10°C or more higher than the glass transition temperature of the thermocompression layer. The temperature for evaluating thermocompression bonding properties may be 250°C or higher and 300°C or lower. When the film material 10 having the thermocompression layer 1 is bonded to another member by thermocompression bonding, the thermocompression layer 1 is heated to a temperature above its glass transition temperature so that it becomes rubbery, and is then pressed against the other member. Normally, the thermocompression layer 1 is not completely crushed during thermocompression bonding and maintains its shape as a "layer," so that the film material 10 can be peeled off and thermocompressed again.

[0015] The thermocompression layer 1 may have a glass transition temperature of 140°C or higher, or 140°C or higher and 280°C or lower. A thermocompression layer 1 having a glass transition temperature of 140°C or higher may be non-adhesive at 25°C. Furthermore, if the thermocompression layer 1 has a high glass transition temperature, deformation such as foaming and wrinkling is less likely to occur in the film material at high temperatures. From a similar perspective, the glass transition temperature of the thermocompression layer 1 may be 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, 190°C or higher, or 200°C or higher. The glass transition temperature of the thermocompression layer 1 may be 280°C or lower, 270°C or lower, 260°C or lower, less than 260°C, 250°C or lower, 240°C or lower, or 230°C or lower. The glass transition temperature of the thermocompression layer 1 may be a value measured by thermomechanical analysis using a strip-shaped test piece cut out from the thermocompression layer 1 or a strip-shaped test piece formed from the same material as the thermocompression layer 1. Thermomechanical analysis for measuring the glass transition temperature is performed under the following conditions: test piece width 2 mm, chuck distance 10 mm, temperature range 30°C to 300°C, in air, heating rate 10°C / min, and tensile load 98 mN. In a curve showing the relationship between the dimensions of the test piece and the temperature, the temperature at the intersection of the tangent to the temperature range in the glassy state and the tangent to the temperature range in the rubbery state can be taken as the glass transition temperature.

[0016] The thermocompression layer 1 may be a resin layer that does not melt at 250° C. or below. "Does not melt at 250° C. or below" means, in other words, that the resin layer does not liquefy at 250° C. For example, if the melting point of the resin layer observed by differential scanning calorimetry exceeds 250° C., the resin layer can be considered not to melt at 250° C. or below.

[0017] The thermocompression layer 1 may contain, for example, one or more resins selected from polyamideimide resin, polycarbonate resin, polyethersulfone resin, and polyarylate resin. The thermocompression layer 1 may contain a polyamideimide resin (particularly a thermoplastic polyamideimide resin). The content of these resins in the thermocompression layer 1 may be 50% by mass or more and 100% by mass or less, 60% by mass or more and 100% by mass or less, 70% by mass or more and 100% by mass or less, 80% by mass or more and 100% by mass or less, 90% by mass or more and 100% by mass or less, or 95% by mass or more and 100% by mass or less, based on the mass of the thermocompression layer 1.

[0018] Polyamide-imide resins can be synthesized, for example, by reacting a diamine with an acid anhydride (e.g., trimellitic anhydride chloride) to form a polyamic acid, followed by imidization of the polyamic acid to form imide groups. In this case, a polyamide-imide resin is formed having structural units derived from the diamine and structural units derived from the acid anhydride. The diamine may contain a compound having two or more aromatic rings and an ether bond (—O—) connecting the aromatic rings. The polyamide-imide resin formed in this case is sometimes referred to as a polyetheramide-imide. Examples of diamines that are compounds having two or more aromatic rings and an ether bond connecting the aromatic rings include 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 1,3-bis(3-aminophenoxy)benzene. The diamine may also contain a compound having a siloxane bond, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane. The diamine may include a compound having an alicyclic compound, an example of which is 1,1-bis(4-aminophenyl)cyclohexane. Other examples of diamines include 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 4,4'-methylenebis(2,6-diisopropylaniline), and 4,7,10-trioxa-1,13-tridecanediamine. By adjusting the type of compound used as the diamine and the monomer ratio, the glass transition temperature of the thermocompression bonding layer containing the polyamideimide resin can be adjusted.

[0019] The thickness of the thermocompression layer 1 may be, for example, 1 μm or more and 2000 μm or less. The thickness of the thermocompression layer 1 may be 5 μm or more, or 10 μm or more, and may be 1000 μm or less, or 500 μm or less.

[0020] The thermocompression layer 1 can be formed, for example, by a method including forming a film of a resin varnish containing a resin selected from polyamideimide resins and an organic solvent, and removing the organic solvent from the resin varnish film. Although the organic solvent may remain in the thermocompression layer 1 formed by this method, the thermocompression layer 1 need not be substantially free of the organic solvent. For example, the content of the organic solvent in the thermocompression layer 1 may be less than 10 ppm by mass based on the mass of the thermocompression layer 1. A small content of the organic solvent is advantageous in terms of suppressing foaming when exposed to high temperatures during or after thermocompression bonding.

[0021] Fig. 2 is a cross-sectional view showing another example of a film material. The film material 10 shown in Fig. 2 is composed of an intermediate layer 2 and two thermocompression layers 1 provided on both sides of the intermediate layer 2. In the example of Fig. 2, the outermost layers on both the first surface S1 side and the second surface S2 side of the film material 10 are thermocompression layers 1. The configuration of the thermocompression layer 1 on the first surface S1 side and the configuration of the thermocompression layer 1 on the second surface S2 side may be the same or different.

[0022] The intermediate layer 2 may be a resin layer, a metal layer, or a combination thereof different from the thermocompression bonding layer 1. The intermediate layer 2 may be, for example, a resin layer containing a polyimide resin, a resin layer containing polyphenylene sulfide, aluminum foil, or copper foil. The thickness of the intermediate layer 2 may be, for example, 1 μm or more and 20,000 μm or less.

[0023] The film material may be transported and stored, for example, in a state where it is wound around a winding core. FIG. 3 is a perspective view showing an example of a wound body having a film material. The wound body 30 shown in FIG. 3 includes a winding core 31, the film material 10 wound around the winding core 31, and a side plate 32. The width (length in a direction perpendicular to the winding direction) of the winding core 31 and the film material 10 may be, for example, 5 mm or more and 500 mm or less. In the wound body 30, the film material 10 is wound around the winding core 31 with the first surface S1 and the second surface S2 in direct contact, without being covered by other members such as a protective film and a support film. Because the thermocompression layer located on the outermost surface of the film material 10 is non-adhesive at room temperature, the wound body 30 in this form can be stably transported and stored at room temperature.

[0024] Various structures can be manufactured by thermocompression bonding the film material according to the present disclosure, which includes a thermocompression layer, to other members. The film material may be used as an adhesive layer for various structures. Examples of structures having the film material as an adhesive layer include fuel cells, multilayer flexible substrates, strain gauges, probe cards, and inkjet heads. The film material can also be used to impart rigidity to wafers.

[0025] For example, the film material can be used as an adhesive layer in a structure including a plurality of sheet-like glass substrates. FIG. 4 is a cross-sectional view showing an example of a wiring substrate, which is a structure including an adhesive layer. The wiring substrate 50 shown in FIG. 4 includes a plurality of sheet-like glass substrates 20, a plurality of adhesive layers 11, conductive wiring layers 3A and 3B, and a conductive via portion 5. The plurality of glass substrates 20 are stacked in the thickness direction of the wiring substrate 50 (structure), and an adhesive layer 11 is provided between adjacent glass substrates 20. At least a portion of the plurality of adhesive layers 11 constituting the wiring substrate 50 (structure) can be the film material according to the present disclosure. The wiring layers 3A and 3B are provided on the glass substrate 20. Of these, the wiring layer 3A is an internal wiring layer provided between adjacent glass substrates 20. The wiring layer 3B is an external wiring layer exposed on the outer surface of the wiring substrate 50. The glass substrate 20 has a through hole 20a, and the via portion 5 includes a portion provided within the through hole 20a. The adhesive layer 11 bonds adjacent glass substrates 20 together and functions as an insulating layer that seals the wiring layer 3A and the via portion 5. The wiring substrate 50 can be obtained, for example, by a method including heating and pressurizing a laminate in which the film material according to the present disclosure and the glass substrates 20 are alternately stacked. The adhesive layer 11 formed from the film material according to the present disclosure has good adhesion to the glass substrate 20 and is also resistant to deformation such as bubbling and wrinkling even at high temperatures.

[0026] The glass substrate constituting a structure such as a wiring board may be, for example, a molded body of soda-lime glass, borosilicate glass, alkali-free glass, ceramic glass, or quartz glass. The shape of the glass substrate is not particularly limited. The shape of the glass substrate when viewed from the thickness direction of the glass substrate may be, for example, polygonal, circular, elliptical, or other irregular shape. The glass substrate may have a rectangular main surface. The main surface here is the surface of the glass substrate when viewed from the thickness direction of the glass substrate. The thickness of the glass substrate may be any appropriate thickness. The thickness of the glass substrate may be, for example, 0.05 mm to 5.0 mm, 0.1 mm to 2.0 mm, 0.7 mm to 1.5 mm, or 1.1 mm to 1.3 mm.

[0027] The visible light transmittance (total light transmittance) of the glass substrate may be, for example, 80% or more and 100% or less, or 90% or more and 100% or less.

[0028] The present invention is not limited to the following examples. 1. Resin Varnish Resin Varnish A In a 5-liter four-neck flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a fractionating column, 270.9 g (0.66 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 8.7 g (0.035 mol) of 1,3-bis(3-aminopropyl)-tetramethyldisiloxane were dissolved in 1950 g of N-methyl-2-pyrrolidone under a nitrogen atmosphere. The resulting solution was cooled to -10°C, and while maintaining that temperature, 149.5 g (0.71 mol) of trimellitic anhydride chloride was added. After the trimellitic anhydride chloride was dissolved, 100 g of triethylamine was added so that the solution temperature did not exceed 10°C. Polyamic acid was produced by a reaction at room temperature for 3 hours. The solution was heated at 180°C for 5 hours to promote imidization, producing polyetheramideimide from the polyamic acid. A solution containing polyetheramideimide was poured into methanol. The precipitated solid was collected and dried. The dried solid was dissolved in N-methyl-2-pyrrolidone, and the resulting solution was poured into methanol to precipitate the solid again. The solid was dried under reduced pressure to obtain a purified powdered polyetheramideimide A (thermoplastic polyamideimide resin). 120 g of this polyetheramideimide A and 3.6 g of a silane coupling agent (manufactured by Dow-Toray Industries, Inc., trade name: XIAMETER (registered trademark) OFS-6040 Silane) were dissolved in 280 g of N-methyl-2-pyrrolidone to obtain a resin varnish A for forming a thermocompression bonded layer.

[0029] Resin Varnish B: In a 5-liter four-neck flask equipped with a thermometer, stirrer, nitrogen inlet tube, and fractionating column, 258.6 g (0.63 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 67.0 g (0.27 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane were dissolved in 1550 g of N-methyl-2-pyrrolidone under a nitrogen atmosphere. The resulting solution was cooled to -10°C, and while maintaining that temperature, 187.3 g (0.89 mol) of trimellitic anhydride chloride was added. After the trimellitic anhydride chloride was dissolved, 100 g of triethylamine was added so that the solution temperature did not exceed 10°C. Polyamic acid was produced by a reaction at room temperature for 3 hours. The solution was heated at 180°C for 5 hours to promote imidization, producing polyetheramideimide from the polyamic acid. The polyetheramideimide solution was then poured into methanol. The precipitated solid was collected and dried. The dried solid was dissolved in N-methyl-2-pyrrolidone, and the resulting solution was poured into methanol to precipitate the solid again. The solid was dried under reduced pressure to obtain a purified powdered polyetheramideimide B (thermoplastic polyamideimide resin). 120 g of this polyetheramideimide B and 3.6 g of a silane coupling agent (manufactured by Dow-Toray Industries, Inc., trade name: XIAMETER (registered trademark) OFS-6040 Silane) were dissolved in 280 g of N-methyl-2-pyrrolidone to obtain a resin varnish B for forming a thermocompression bonded layer.

[0030] Resin Varnish C Resin varnish C for forming a thermocompression layer was obtained by dissolving 18 g of polyetheramideimide A synthesized in the preparation of resin varnish A, 102 g of polyetheramideimide B synthesized for the preparation of resin varnish B, and 3.6 g of a silane coupling agent (manufactured by Dow-Toray Industries, Inc., trade name: XIAMETER (registered trademark) OFS-6040 Silane) in 280 g of N-methyl-2-pyrrolidone.

[0031] Resin Varnish D: In a 5-liter four-neck flask equipped with a thermometer, stirrer, nitrogen inlet tube, and fractionating column, 235.3 g (0.80 mol) of 1,3-bis(3-aminophenoxy)benzene and 85.6 g (0.34 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane were dissolved in 1500 g of N-methyl-2-pyrrolidone under a nitrogen atmosphere. The resulting solution was cooled to -10°C, and while maintaining that temperature, 239.7 g (1.14 mol) of trimellitic anhydride chloride was added. After the trimellitic anhydride chloride was dissolved, 138.0 g (1.36 mol) of triethylamine was added, ensuring that the solution temperature did not exceed 10°C. Polyamic acid was produced by a 3-hour reaction at room temperature. The solution was heated at 180°C for 5 hours to promote imidization, producing polyetheramideimide from the polyamic acid. The polyetheramideimide solution was then poured into methanol. The precipitated solid was collected and dried. The dried solid was dissolved in N-methyl-2-pyrrolidone, and the resulting solution was poured into methanol to precipitate the solid again. The solid was dried under reduced pressure to obtain a purified powdered polyetheramideimide D (thermoplastic polyamideimide resin). 120 g of this polyetheramideimide D and 6.0 g of a silane coupling agent (manufactured by Dow-Toray Industries, Inc., trade name: XIAMETER™ OFS-6040 Silane) were dissolved in 280 g of N-methyl-2-pyrrolidone to obtain a resin varnish D for forming a thermocompression bonded layer.

[0032] Resin Varnish E: In a 5-liter four-neck flask equipped with a thermometer, stirrer, nitrogen inlet tube, and fractionating column, 172.4 g (0.42 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 153.7 g (0.42 mol) of 4,4'-methylenebis(2,6-diisopropylaniline) were dissolved in 1550 g of N-methyl-2-pyrrolidone under a nitrogen atmosphere. The resulting solution was cooled to -10°C, and while maintaining that temperature, 174.7 g (0.83 mol) of trimellitic anhydride chloride was added. After the trimellitic anhydride chloride was dissolved, 130 g of triethylamine was added so that the solution temperature did not exceed 10°C. Polyamic acid was produced by a 3-hour reaction at room temperature. The solution was heated at 180°C for 5 hours to promote imidization, producing polyetheramideimide from the polyamic acid. The polyetheramideimide solution was then poured into methanol. The precipitated solid was collected and dried. The dried solid was dissolved in N-methyl-2-pyrrolidone, and the resulting solution was poured into methanol to precipitate the solid again. The solid was dried under reduced pressure to obtain a purified powdered polyetheramideimide E (thermoplastic polyamideimide resin). 120 g of this polyetheramideimide E and 6.0 g of a silane coupling agent (manufactured by Dow-Toray Industries, Inc., trade name: XIAMETER (registered trademark) OFS-6040 Silane) were dissolved in 280 g of N-methyl-2-pyrrolidone to obtain a resin varnish E for forming a thermocompression bonding layer.

[0033] 2. Glass Transition Temperature of Thermocompression Layer Resin varnish A, B, C, D, or E was applied to a support film. The coating was dried by heating at 100°C for 10 minutes and at 300°C for 10 minutes, forming a thermocompression layer approximately 40 μm thick on the support film. A rectangular test piece measuring 2 mm wide x 25 mm long was cut from the thermocompression layer peeled from the support film. This test piece was attached to a chuck for measuring the tensile mode of a thermomechanical analyzer (Hitachi High-Tech Corporation, TMA / SS7100). The chuck distance was 10 mm. Measurements were performed in air at a temperature range of 30°C to 300°C, with a heating rate of 10°C / min and a tensile load of 98 mN. In the curve of the measurement results showing the relationship between the dimensions of the test piece and the temperature, the glass transition temperature of the thermocompression-bonded layer formed from resin varnish A, B, C, D, or E was determined from the intersection of the tangent to the temperature range in the glassy state and the tangent to the temperature range in the rubbery state. None of the thermocompression-bonded layers formed from resin varnish A, B, C, D, or E melted at 250°C.

[0034] 3. Thermocompression Bondability Examples A to E Resin varnish A, B, C, D, or E was applied to one side of a polyimide substrate (Kapton EN type, 0.025 mm thick, manufactured by DuPont-Toray Co., Ltd.), and the coating was dried by heating at 140°C for 10 minutes to form a 10 μm-thick thermocompression layer (polyamideimide resin layer). The same type of resin varnish was then applied to the side of the polyimide substrate opposite the thermocompression layer, and the coating was dried by heating at 300°C for 10 minutes to form 10 μm-thick thermocompression layers (polyamideimide resin layers) on both sides of the polyimide substrate. From the resulting three-layer laminate film (total thickness approximately 0.045 mm), a test strip film measuring 10 mm wide x 50 mm long was cut out. The cut strip-shaped film was overlapped with a glass plate (Toshin Riko Co., Ltd., soda-lime glass, 28 mm wide x 48 mm long x 1.3 mm thick, total light transmittance 90% or more). The formed laminate was sandwiched between the upper and lower heat stages of a thermocompression machine. The laminate was then pressed at a pressure of 6 MPa for 10 seconds at a predetermined pressure temperature to obtain a bonded structure for a peel test after thermocompression bonding. The pressure was set to Tg + 10°C or Tg + 20°C, where Tg is the glass transition temperature of each thermocompression layer. For Examples B, C, and D, a bonded structure for a peel test after thermocompression bonding was also obtained at a pressure temperature of 250°C. The pressure (6 MPa) under the thermocompression bonding conditions was the pressure applied to the strip-shaped film. Fluororesin tape (160 μm thick) was attached to the upper and lower heat stages and interposed between each heat stage and the laminate. Except for changing the temperature of the thermocompression machine to 25°C, an adhesive bond for peel test after room temperature compression bonding was obtained in the same manner.

[0035] Comparative Example A: A sheet-like laminate of aluminum foil and a resin layer (thickness: approximately 40 μm) containing polyethylene (PE) was prepared. A strip-shaped film having a width of 10 mm and a length of 50 mm was cut out from this laminate. The cut strip-shaped film and a glass plate were overlapped with the resin layer facing the glass plate, and the resulting laminate was sandwiched between the upper and lower heat stages of a thermocompression bonder and heated to a bonding temperature of 80 ° C. or 140 ° C. while being pressed at a pressure of 6 MPa for 10 seconds. A peel test was performed on the bonded body obtained at a bonding temperature of 80 ° C. or 140 ° C. The pressure (6 MPa) under the thermocompression bonding conditions was the pressure applied to the strip-shaped film. Fluororesin tape (thickness: 160 μm) was attached to the upper and lower heat stages, and this was interposed between each heat stage and the laminate. An adhesive for a peel test after room temperature compression bonding was obtained in the same manner, except that the temperature of the thermocompression bonder was changed to 25 ° C. The glass transition temperatures of the polyethylene-containing resin layers shown in Table 2 are values ​​of Tmg measured by differential scanning calorimetry in accordance with the method for measuring the glass transition temperature of plastics specified in Japanese Industrial Standard JIS K7121-1987.

[0036] Comparative Example B A sheet-like laminate of aluminum foil and a resin layer (thickness: approximately 40 μm) containing polyethylene terephthalate (PET) was prepared. A strip-shaped film measuring 10 mm wide x 50 mm long was cut out from this laminate. The cut strip-shaped film and a glass plate were overlapped with the resin layer facing the glass plate. The formed laminate was sandwiched between the upper and lower heat stages of a thermocompression machine. The laminate was then heated to a bonding temperature of 80°C, 90°C, or 250°C and pressed at a pressure of 6 MPa for 10 seconds. The pressure (6 MPa) under the thermocompression bonding conditions was the pressure applied to the strip-shaped film. Fluororesin tape (thickness: 160 μm) was attached to the upper and lower heat stages and interposed between each heat stage and the laminate. At a bonding temperature of 80°C or 90°C, the resin layer did not adhere to the glass plate, and no adhesive for peel testing was obtained. A peel test was carried out on the bonded structure obtained at a compression temperature of 250°C. Bonded structures for the peel test after room temperature compression were obtained in the same manner except that the temperature of the thermocompression machine was changed to 25°C. The glass transition temperatures of the polyethylene terephthalate-containing resin layers shown in Table 2 are values ​​of Tmg measured by differential scanning calorimetry in accordance with the method for measuring transition temperatures of plastics in Japanese Industrial Standard JIS K7121-1987.

[0037] Comparative Example C A sheet-like laminate of aluminum foil and a thermosetting resin layer containing an epoxy resin (epoxy adhesive film, thickness: approximately 40 μm) before curing was prepared. A strip-shaped film measuring 10 mm wide x 50 mm long was cut out from this laminate. The cut strip-shaped film and a glass plate were overlapped with the resin layer facing the glass plate. The formed laminate was sandwiched between the upper and lower heat stages of a thermocompression bonder. The laminate was then heated to 100 ° C or 140 ° C and pressed at a pressure of 6 MPa for 10 seconds to obtain an adhesive for a peel test after thermocompression bonding. The pressure (6 MPa) under the thermocompression bonding conditions was the pressure applied to the strip-shaped film. Fluororesin tape (thickness 160 μm) was attached to the upper and lower heat stages, and this was interposed between each heat stage and the laminate. An adhesive for a peel test after room temperature compression bonding was obtained in the same manner, except that the temperature of the thermocompression bonder was changed to 25 ° C. The glass transition temperature of a thermosetting resin layer containing an epoxy resin before curing was measured based on the temperature dependence of dynamic viscoelasticity. An epoxy resin-containing resin layer (approximately 100 μm thick) was formed before curing. A rectangular test piece measuring 4 mm wide x 30 mm long was cut from the resin layer. This test piece was mounted on a dynamic viscoelasticity measuring instrument (Rheogel-E4000, manufactured by UBM Corporation) with a chuck distance of 20 mm. The dynamic viscoelasticity of the test piece was measured in tensile mode, at a heating rate of 3°C / min, over a temperature range of 30°C to 200°C, in air, with a frequency of 10 Hz (constant), sinusoidal, continuous vibration, and manual initial load control. From the measurement results, the temperature at which the Tan δ value of the epoxy resin-containing resin layer before curing reached its maximum was determined as the glass transition temperature.

[0038] Peel test: The 90° peel strength between the thermocompression layer or resin layer and the glass plate was measured by a 90° peel test in which the laminate film including the thermocompression layer or the laminate consisting of aluminum foil and a resin layer was peeled off from the glass plate of each adhesive bond while being pulled in a direction at 90° relative to the surface of the glass plate. The pulling speed was 50 mm / min. The 90° peel test was performed under conditions where the temperature of the adhesive bond was 25°C or 200°C, and the 90° peel strength at each temperature was determined.

[0039] 4. Heat Resistance Examples A to E Resin varnishes A, B, C, D, and E were each applied to a peelable support film after drying. The coating was dried by heating at 100°C for 10 minutes and then at 300°C for 10 minutes, forming a thermocompression layer approximately 40 μm thick on the support film. A rectangular test piece measuring 10 mm wide x 30 mm long was cut from the thermocompression layer peeled from the support film. The test piece was heat-treated at 120°C for 10 seconds to remove absorbed moisture. The heat-treated test piece (thermocompression layer) was sandwiched between two glass plates, and an evaluation sample having a glass plate / thermocompression layer / glass plate configuration was placed on a hot plate set at an actual temperature of 200°C, 220°C, 250°C, or 260°C for 10 seconds. The thermocompression layer of the evaluation sample was then observed to determine the presence or absence of foaming or wrinkling, wetting, and adhesion to the glass plate. If no such changes are observed, it can be determined that the thermocompression bonded layer has good heat resistance. The evaluation results are shown in Table 1.

[0040]

[0041] Comparative Examples A to C: Strip-shaped test pieces of a resin layer containing polyethylene, a resin layer containing polyethylene terephthalate, or a thermosetting pre-cured resin layer containing an epoxy resin were prepared, and heat resistance was evaluated by heating while sandwiched between glass plates in the same manner as above. In the case of the resin layer containing polyethylene, the resin layer melts at 120°C, so the heat treatment at 120°C for 10 seconds to remove absorbed moisture was not performed. The evaluation results are shown in Table 2.

[0042]

[0043] 1...thermocompression layer, 2...intermediate layer, 3A, 3B...wiring layer, 5...via portion, 10...film material, 11...adhesive layer, 20...glass substrate, 30...wound body, 31...winding core, 50...wiring board (structure), S1...first surface, S2...second surface

Claims

1. A film material having a first surface and a second surface on the reverse side thereof, the film material including one or more thermocompression layers, the thermocompression layers being resin layers that are non-adhesive at 25°C, have thermocompression bondability at a temperature 10°C or higher than the glass transition temperature of the thermocompression layers, and do not melt at temperatures below 250°C, the thermocompression layers being the outermost layers on both the first surface side and the second surface side.

2. The film material according to claim 1, wherein the thermocompression layer contains a polyamideimide resin.

3. The film material according to claim 1, wherein the thermocompression layer contains a polycarbonate resin, a polyethersulfone resin, or a polyarylate resin.

4. The film material according to claim 1, wherein the content of the organic solvent in the thermocompression layer is less than 10 ppm by mass based on the mass of the thermocompression layer.

5. A wound body comprising: the film material according to any one of claims 1 to 4; and a winding core, wherein the film material is wound around the winding core with the first surface and the second surface in direct contact with each other.

6. A structure comprising a plurality of sheet-like glass substrates and an adhesive layer, wherein the glass substrates are stacked in the thickness direction of the structure, the adhesive layer is provided between adjacent glass substrates, and at least a portion of the adhesive layer is the film material described in any one of claims 1 to 4.

7. A wiring board comprising a plurality of sheet-like glass substrates, an adhesive layer, and a wiring layer, wherein the glass substrates are stacked in the thickness direction of the wiring board, the adhesive layer and the wiring layer are provided between adjacent glass substrates, and at least a portion of the adhesive layer is a film material according to any one of claims 1 to 4.

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