CN114132027A - Method for manufacturing release film and method for manufacturing circuit substrate - Google Patents

Abstract

The invention provides a release film, which can prevent resin from seeping out from a specific resin layer by setting the end part of the film to be a specific structure. The method for manufacturing the release film comprises a step of forming a covering part (14), wherein the covering part (14) covers at least a part of the end face (11E) of a1 st resin layer (11) of a laminated body comprising the 1 st resin layer (11) and a2 nd resin layer (12).

Description

Method for manufacturing release film and method for manufacturing circuit substrate

Technical Field

The invention relates to a method for manufacturing a release film and a method for manufacturing a circuit substrate.

Background

Conventionally, in the manufacture of a circuit board such as an FPC (flexible printed circuit), a hot-pressing step is generally performed. In the hot pressing step, a release film is used to prevent the circuit board from adhering to the hot press board. Release films are required to have properties such as heat resistance to withstand hot press molding, releasability from FPC and hot press board, non-staining property to copper circuit, and easiness of disposal.

In recent years, the L/S (line pitch) of FPCs has been increasingly thinned, and the required quality of release films has been improved, and improvement of the concave-convex following property has been required. In order to improve the unevenness follow-up property, the release film may have a multilayer structure, and a material having high flexibility is used for any layer. Specifically, a surface layer and an intermediate layer are usually provided, and a material having high flexibility is used for the intermediate layer. As a material having high flexibility used for the intermediate layer and the like, it is known to use a polyolefin resin such as Polyethylene (PE) and an ethylene-methyl methacrylate copolymer (EMMA) (for example, see patent document 1).

Prior art documents

Patent document 1: japanese patent laid-open publication No. 2007-98816

Disclosure of Invention

However, resins having high flexibility such as PE and EMMA have a low melting point and may melt or flow during pressurization and bleed out from the film ends. The resin that has oozed out may adhere to auxiliary materials such as a circuit board, a platen, and a cushion material disposed inside the platen, thereby causing contamination.

Accordingly, an object of the present invention is to provide a release film capable of preventing bleeding from a specific resin layer such as an intermediate layer during hot pressing. Another object of the present invention is to provide a method for manufacturing a circuit board which is less likely to cause contamination.

As a result of earnest studies, the present inventors have found that the above problems can be solved by using a release film having a multilayer structure, in which the film end portion has a specific structure, or a circuit board is manufactured using a release film having a specific structure, and the present invention has been completed. Namely, the present invention provides the following [1] to [12 ].

[1] A method for manufacturing a release film includes a step of forming a coating portion that covers at least a part of an end face of a1 st resin layer of a laminate including the 1 st resin layer and a2 nd resin layer.

[2] The method of manufacturing a release film according to [1], comprising a step of cutting the laminate, wherein at least a part of an end face of the 1 st resin layer is covered with the 2 nd resin layer by the cutting, thereby forming the covered portion.

[3] The method for producing a release film according to the above [2], wherein the cutting is performed by at least one of press cutting, shear cutting and melt cutting.

[4] The method of manufacturing a release film according to the above [1], wherein the covering portion is formed using a member for covering.

[5] The method of manufacturing a release film according to item [1], wherein the 2 nd resin layer is provided with protruding portions that protrude outward beyond the end faces of the 1 st resin layer, and the protruding portions are fixed to each other.

[6] The method of manufacturing a release film according to item [5], wherein the protruding portions are fixed to each other by at least one of a fixing member, an adhesive, welding, and crimping.

[7] A method for manufacturing a release film, comprising the steps of: the end of the laminate provided with the 1 st resin layer and the 2 nd resin layer is folded back inward to form a folded-back portion.

[8] The method of manufacturing a release film according to item [7], wherein the folded portion is fixed by at least one of a fixing member, an adhesive, welding, and pressure bonding.

[9] A method for manufacturing a circuit board, wherein a circuit board is manufactured by using a release film which is provided with a1 st resin layer and a2 nd resin layer and has a covering part for covering an end face of the 1 st resin layer, and the 2 nd resin layer is provided on at least one side of the 1 st resin layer and has a composition different from that of the 1 st resin layer.

[10] A method for manufacturing a circuit board using a release film, the release film including a1 st resin layer and a2 nd resin layer, the 2 nd resin layer being provided on at least one surface side of the 1 st resin layer and having a composition different from that of the 1 st resin layer, the 2 nd resin layer having a protruding portion protruding outward from an end surface of the 1 st resin layer.

[11] A method for manufacturing a circuit board using a release film, the release film having a1 st resin layer and a2 nd resin layer and having a folded portion, the 2 nd resin layer being provided on at least one surface side of the 1 st resin layer and having a composition different from that of the 1 st resin layer.

[12] A method for manufacturing a circuit board, wherein a1 st resin layer and a2 nd resin layer having a composition different from that of the 1 st resin layer are prepared, the method comprising a laminating step of laminating the 1 st resin layer having a smaller size than that of the 2 nd resin layer and further laminating the 2 nd resin layer having a larger size than that of the 1 st resin layer on the 2 nd resin layer, and pressing is performed after the laminating step.

The present invention also provides the following [13] to [38 ].

[13] A release film comprises a1 st resin layer and a2 nd resin layer, and has a coating portion for coating an end face of the 1 st resin layer, wherein the 2 nd resin layer is provided on at least one surface side of the 1 st resin layer and has a composition different from that of the 1 st resin layer.

[14] The release film according to item [13], wherein the 2 nd resin layer forms the coating portion.

[15] The release film according to item [14], which comprises the 2 nd resin layers on both sides of the 1 st resin layer, wherein the 2 nd resin layers form the covering portion.

[16] The release film according to the above [14] or [15], wherein the 2 nd resin layer provided on the one surface and forming the covering portion is connected to the 2 nd resin layer on the other surface side of the 1 st resin layer.

[17] The release film according to any one of the above [14] to [16], wherein the 2 nd resin layer is provided on each of both surfaces of the 1 st resin layer, and the 2 nd resin layer has a protruding portion protruding outward from an end surface of the 1 st resin layer.

[18] The release film according to the above [17], wherein the length of the protruding portion is greater than the average thickness of the 2 nd resin layer.

[19] The release film according to the above [17] or [18], wherein the protruding portions are joined to each other.

[20] The release film according to the above [19], which has a pressure-bonding part in which the protruding parts are bonded to each other by pressing.

[21] The release film according to the above [20], wherein a thickness of the pressure-bonding part is smaller than a sum of average thicknesses of the respective 2 nd resin layers.

[22] The release film according to item [13], wherein the covering part is formed of a covering member.

[23] The release film according to the above [22], wherein the covering member is a resin film.

[24] The release film according to the above [22], wherein the covering member is a sealant.

[25] The release film according to any one of the above [13] to [24], which has a polygonal planar shape and is provided with a covering portion on at least 2 sides thereof.

[26] The release film according to any one of the above [13] to [25], wherein the covering portion has an inclined surface.

[27] The release film according to any one of the above [13] to [26], further comprising a 3 rd resin layer provided between the 1 st resin layer and the 2 nd resin layer.

[28] A release film comprises a1 st resin layer and a2 nd resin layer, wherein the 2 nd resin layer is arranged on at least one side of the 1 st resin layer and has a composition different from that of the 1 st resin layer, and the 2 nd resin layer has a protruding part protruding outwards from an end face of the 1 st resin layer.

[29] The release film according to item [28], wherein the 2 nd resin layers are provided on both sides of the 1 st resin layer, and each of the 2 nd resin layers has a protruding portion.

[30] The release film according to item [29], wherein a projecting length L1 of at least one projecting portion of the 2 nd resin layer is 5mm or more.

[31] The release film according to the above [29] or [30], which comprises fixing portions for fixing the projecting portions of the 2 nd resin layers to each other, wherein a space is provided between the fixing portions and the 1 st resin layer.

[32] The release film according to any one of the above [28] to [31], which has a polygonal planar shape and is provided with a covering portion on at least 2 sides thereof.

[33] The release film according to any one of the above [28] to [32], further comprising a 3 rd resin layer provided between the 1 st resin layer and the 2 nd resin layer.

[34] A release film comprises a1 st resin layer and a2 nd resin layer, and has a folded portion, wherein the 2 nd resin layer is provided on at least one surface side of the 1 st resin layer and has a composition different from that of the 1 st resin layer.

[35] The release film according to item [34], wherein the end face of the 1 st resin layer faces inward with respect to an outer edge of the release film.

[36] The release film according to the above [34] or [35], wherein a folded length L2 of the folded portion of the 2 nd resin layer is 5mm or more.

[37] The release film according to any one of the above [34] to [36], which has a polygonal planar shape and is provided with a covering portion on at least 2 sides thereof.

[38] The release film according to any one of the above [34] to [37], further comprising a 3 rd resin layer provided between the 1 st resin layer and the 2 nd resin layer.

According to the present invention, by making the film end portion have a specific structure, it is possible to prevent the resin from bleeding out from a specific resin layer such as an intermediate layer. Further, a method for manufacturing a circuit board without causing contamination can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 1 of the present invention.

Fig. 2 is a schematic cross-sectional view showing an end structure of a release film according to a modification of embodiment 1 of the present invention.

Fig. 3 is a schematic view showing a method for manufacturing a release film according to embodiment 1 of the present invention.

Fig. 4 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 2 of the present invention.

Fig. 5 is a schematic view showing a method for manufacturing a release film according to embodiment 2 of the present invention.

Fig. 6 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 3 of the present invention.

Fig. 7 is a schematic view showing a method for manufacturing a release film according to embodiment 3 of the present invention.

Fig. 8 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 4 of the present invention.

Fig. 9 is a schematic view showing a method for manufacturing a release film according to embodiment 4 of the present invention.

Fig. 10 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 5 of the present invention.

Fig. 11 is a schematic view showing a method for manufacturing a release film according to embodiment 5 of the present invention.

Fig. 12 is a schematic cross-sectional view showing an end structure of a release film according to a modification of embodiment 5 of the present invention.

Fig. 13 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 6 of the present invention.

Fig. 14 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 7 of the present invention.

Fig. 15 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 8 of the present invention.

Fig. 16 is a schematic cross-sectional view showing an end structure of a modified example of the release film according to embodiment 8 of the present invention.

Fig. 17 is a schematic cross-sectional view showing an end structure of a release film according to embodiment 9 of the present invention.

Fig. 18 is a schematic cross-sectional view showing an end structure of a release film according to a modification of embodiment 1 of the present invention.

Fig. 19 is a schematic cross-sectional view showing an end structure of a release film according to a modification of embodiment 9 of the present invention.

Fig. 20 is a schematic cross-sectional view showing an end structure of a release film according to a modification of embodiment 1 of the present invention.

Description of the reference numerals

10. 20, 30, 40, 50, 60, 70, 80 and 90 release film

11. 21, 31, 41, 51, 61, 71, 81, 91 the 1 st resin layer

End faces of the 11E, 21E, 31E, 41E, 51E, 61E, 71E, 81E, 91E 1 st resin layer

12. 13, 22, 23, 32, 33, 42, 43, 52, 53, 62, 63, 72, 73, 82, 83, 92, 93 No. 2 resin layer

14. 24, 34, 44, 54, 64, 74 covered part

16. 26, 36, 46, 56 laminate

17 press cutting edge

27 shearing edge

37 heating blade

48. 58 crimping part

57 pressure welding unit

82E, 83E extensions

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

< embodiment 1 >

Fig. 1 shows an end structure of a release film 10 according to embodiment 1 of the present invention. As shown in fig. 1, the release film 10 includes a1 st resin layer 11 and 2 nd resin layers 12 and 13 provided on both surfaces 11A and 11B of the 1 st resin layer 11, respectively. The surfaces 11A and 11B constitute the main surface of the 1 st resin layer 11. The release film 10 is a laminate in which a2 nd resin layer 12, a1 st resin layer 11, and a2 nd resin layer 13 are integrated. The release film 10 is a multilayer film, and a2 nd resin layer 12, a1 st resin layer 11, and a2 nd resin layer 13 are disposed in this order.

In the release film 10, the 1 st resin layer 11 is an intermediate layer disposed between the 2 nd resin layers 12 and 13, and may have cushioning properties. That is, the 1 st resin layer 11 may have a flowable or soft property at a temperature at which the pressing is performed. The 2 nd resin layers 12, 13 are surface layers constituting the outermost surface of the release film 10. The 2 nd resin layers 12 and 13 may have releasability from a mold, and as described later, for example, in the production of a circuit board, the resin layers may have releasability from a circuit board, a pressure plate, a cushion material, or the like. That is, after pressing, the sheet can be easily peeled off from the object to be pressed. The release film 10 has good releasability from a platen, a circuit board, or the like and good conformability to irregularities of the circuit board by including the 1 st resin layer 11 in addition to the 2 nd resin layers 12 and 13.

The resin constituting the first resin layer 11 is not particularly limited, and examples thereof include polyolefin resins. Examples of the polyolefin resin include polyethylene such as low-density polyethylene, linear low-density polyethylene, and ultrahigh-molecular-weight polyethylene, polypropylene such as homo-polypropylene and random polypropylene, ethylene-acrylic acid monomer copolymers such as ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-acrylic acid copolymer, and ethylene-vinyl acetate copolymer. These may be used alone, or 2 or more of them may be used in combination. Among them, low-density polyethylene, linear low-density polyethylene, ethylene-methyl methacrylate copolymer, and ethylene-vinyl acetate copolymer are preferable.

The resin constituting the 1 st layer 11 may be a polyolefin resin alone, but may contain a resin other than a polyolefin resin such as polystyrene, polyvinyl chloride, polyamide, polycarbonate, polysulfone, and polyester, within a range not to impair the object of the present invention.

However, the layer 1 11 contains a polyolefin resin as a main component, and the polyolefin resin may be contained in an amount of, for example, 50 mass% or more, preferably 70 mass% or more of the entire resin component contained in the layer 1 11.

The 2 nd resin layers 12 and 13 have a different composition from the 1 st resin layer 11, and for example, different kinds of resins may be used. Examples of the resin used for the 2 nd resin layers 12 and 13 include polyester resins, polyolefin resins, and polystyrene resins. These may be used alone, or 2 or more of them may be used in combination. Among them, polyester resins are more preferable.

Therefore, it is further preferable that: the resin used for the 1 st resin layer 11 is a polyolefin resin, and the resins used for the 2 nd resin layers 12 and 13 are polyester resins.

The resin used for the 2 nd resin layers 12 and 13 may be the same type of resin as that used for the 1 st resin layer 11, and for example, the resin used for the 1 st resin layer 11 and the 2 nd resin layers 12 and 13 may be a polyolefin resin.

In the case of using the same kind of resin, for example, at least one of the molecular weight, the kind of the monomer constituting the resin, and the molar ratio of the monomer constituting the resin in the case of using a copolymer may be different. In addition, 2 or more kinds of resins may be contained in any one of the 1 st resin layer 11 and the 2 nd resin layers 12 and 13, and the blending ratio of the respective resins may be appropriately different.

The polyester resin used in the 2 nd resin layer can be obtained, for example, by reacting a 2-valent acid or an ester-forming derivative thereof as an acid component with a diol component.

The acid component is preferably an aromatic dicarboxylic acid or an ester-forming derivative thereof, and the polyester resin is preferably a crystalline aromatic polyester resin having crystallinity and an aromatic dicarboxylic acid as the acid component.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, and p-phenylene dicarboxylic acid. Further, as the ester-forming derivative of the aromatic dicarboxylic acid, there may be mentioned the above-mentioned ester-forming derivatives of the aromatic dicarboxylic acid, and specific examples thereof include dimethyl terephthalate, dimethyl isophthalate, dimethyl phthalate, dimethyl naphthalenedicarboxylate, dimethyl p-phenylenedicarboxylate, and the like. These may be used alone, or 2 or more of them may be used in combination.

The diol component may be a low-molecular-weight aliphatic diol, or a combination of a low-molecular-weight aliphatic diol and a high-molecular-weight diol.

Examples of the low-molecular-weight aliphatic diol include ethylene glycol, 1, 2-propanediol, 1, 3-butanediol, 1, 4-butanediol, neopentyl glycol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 4-cyclohexanedimethanol, and the like. These may be used alone, or 2 or more of them may be used in combination.

Examples of the high molecular weight diol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyhexamethylene glycol. These may be used alone, or 2 or more of them may be used in combination.

Specific examples of the crystalline aromatic polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate-polytetramethylene copolymer, and polybutylene terephthalate-polycaprolactone copolymer. These may be used alone, or 2 or more of them may be used in combination. Among them, polybutylene terephthalate is preferable because it is particularly excellent in non-staining property and crystallinity.

As the polyolefin-based resin used for the 2 nd resin layer, a resin containing poly (4-methyl-1-pentene) as a main component and a resin containing an alicyclic olefin-based resin as a main component can be suitably used. As the polystyrene resin, a resin containing a polystyrene resin having a syndiotactic structure as a main component, and the like can be suitably used.

The resin used for the second resin layers 12 and 13 may be composed of only a resin selected from the polyester-based resin, the polyolefin-based resin, and the polystyrene-based resin, but may contain other thermoplastic resins and rubber components in addition to the above-mentioned polyester-based resin, polyolefin-based resin, and polystyrene-based resin, as long as the properties as the release layer are not impaired.

The other thermoplastic resins are not particularly limited, and examples thereof include polyolefins, modified polyolefins, polystyrenes, polyvinyl chlorides, polyamides, polycarbonates, polysulfones, polyesters, and the like. The rubber component is not particularly limited, and examples thereof include natural rubber, styrene-butadiene copolymer, polybutadiene, polyisoprene, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer (EPM, EPDM), polychloroprene, butyl rubber, acrylic rubber, silicone rubber, urethane rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, ester-based thermoplastic elastomer, and amide-based thermoplastic elastomer.

These thermoplastic resin and rubber components can be used alone in 1 kind, also can be combined with more than 2 kinds.

The resin selected from the polyester-based resin, the polyolefin-based resin, and the polystyrene-based resin may be used as a main component in each of the 2 nd resin layers 12 and 13, and may be, for example, 50 mass% or more, preferably 70 mass% or more of the entire resin components contained in the 2 nd resin layer.

The 2 nd resin layers 12 and 13 may have different compositions from each other or the same composition. The release film 10 can be easily manufactured if it has the same composition.

Further, additives may be appropriately added to the resins constituting the 1 st resin layer 11 and the 2 nd resin layers 12 and 13. Examples of the additive include fibers, inorganic fillers, flame retardants, ultraviolet absorbers, antistatic agents, inorganic substances, higher fatty acid salts, and the like.

In order to ensure the cushioning properties of the 1 st resin layer 11, the modulus of elasticity in a high-temperature environment is preferably lower than that of the 2 nd resin layers 12 and 13. Specifically, the storage modulus (storage elastic modulus) of the 1 st resin layer 11 may be lower than that of the 2 nd resin layers 12, 13, respectively. The storage modulus is a storage modulus at 180 ℃ measured by a dynamic viscoelasticity measuring apparatus (for example, DVA-200 manufactured by IT measurement and control).

Measurement mode stretching

The temperature rise rate is 5 ℃/min

Data acquisition interval 1 deg.C/min

Measuring frequency 1Hz

Deformation 0.1%

Static/dynamic ratio 2

Minimum load 1cN

The above-mentioned storage modulus of the 1 st resin layer 11 is particularly preferably 1.0 × 10⁶～1.5×10⁷Pa。

The storage modulus of the 2 nd resin layers 12 and 13 may be, for example, more than 1.5 × 10⁷Pa, preferably 1.5X 10⁷～5.0×10⁸Pa。

In addition, the flow starting temperature of the 1 st resin layer 11 may be lower than that of the 2 nd resin layers 12, 13. The flow starting temperature is a temperature at which, for example, when a sample (for example, 25mm × 25mm) of each layer of the monomer is placed on a hot plate or the like and heated from room temperature at about 10 ℃/minute, the sample area expands by 10% or more due to the flow.

The flow starting temperature of the 1 st resin layer may be selected or adjusted according to the hot pressing temperature, and for example, may be 80 to 200 ℃, may be in the range of 80 to 120 ℃, may be in the range of 120 to 160 ℃, and may be in the range of 160 to 200 ℃. Similarly, the flow starting temperature of the 2 nd resin layer may be selected or adjusted according to the hot pressing temperature, and for example, may be 160 to 280 ℃, may be 160 to 200 ℃, may be 200 to 240 ℃, and may be 240 to 280 ℃.

The flow starting temperature of the 1 st resin layer is preferably 20 ℃ or more lower than the temperature at which hot pressing is performed. More preferably 30 ℃ or higher, still more preferably 40 ℃ or higher, and particularly preferably 50 ℃ or higher.

The flow starting temperature of the 2 nd resin layer is preferably 20 ℃ or higher than the temperature at which hot pressing is performed. More preferably 30 ℃ or higher, still more preferably 40 ℃ or higher, and particularly preferably 50 ℃ or higher.

The difference between the flow start temperature of the 1 st resin layer and the flow start temperature of the 2 nd resin layer is preferably 40 ℃ or more. More preferably 60 ℃ or higher, and still more preferably 80 ℃ or higher.

From the viewpoint of ensuring appropriate cushioning properties and concave-convex following properties, the thickness of the 1 st resin layer 11 is preferably larger than the thicknesses of the 2 nd resin layers 12 and 13, respectively. The thickness of the 1 st resin layer 11 is, for example, 5 to 200 μm, preferably 10 to 150 μm, and more preferably 20 to 100 μm.

The thickness of each of the 2 nd resin layers 12 and 13 is preferably 1 to 100 μm, more preferably 5 to 50 μm, and still more preferably 10 to 20 μm. By setting the thickness to 1 μm or more, the release film can be prevented from cracking during transportation, press molding, or the like. Further, by setting the thickness to 100 μm or less, it is possible to prevent the deterioration of the concave-convex following property and the like at the time of press molding.

The thickness of each resin layer is an average thickness, and for example, an average thickness measured at 10 points other than the end of the release film can be used.

As shown in fig. 1, in the present embodiment, one resin layer 12 of the pair of 2 nd resin layers 12 and 13 forms a covering portion 14 that covers the end face 11E. In the embodiment shown in fig. 1, the 2 nd resin layer 12 is coated with the 1 st resin layer 11 from the top of the one surface 11A to the top of the end surface 11E of the 1 st resin layer 11. The release film 10 can prevent the resin constituting the 1 st resin layer 11 from bleeding out from the end face 11E even if heated and pressurized at the time of press working or the like by providing the covering portion 14.

In the present specification, "covered" means that the end face or the surface is covered, and may not necessarily be in contact with the object to be covered. Further, it is not necessary to adhere to the object to be coated, and a space may be present between the coating portion and the end face or the surface.

As shown in fig. 1, the 2 nd resin layer 12 preferably covers the entire end face 11E of the 1 st resin layer 10 in cross section and is connected to the 2 nd resin layer 13 disposed on the other face 11B of the 1 st resin layer 11. In this way, the pair of 2 nd resin layers 12 and 13 are connected to each other, whereby the resin can be more effectively prevented from oozing out from the end surfaces.

However, as shown in fig. 2, it is also possible to: the 2 nd resin layer 12 does not need to cover the entire end face 11E in cross section, and the 2 nd resin layers 12 and 13 are not connected to each other.

In the structure shown in fig. 1, the 2 nd resin layers 12 and 13 are in direct contact with each other, but the 2 nd resin layers 12 and 13 do not necessarily need to be in direct contact with each other, and may be connected to each other through a member other than the 1 st resin layer such as the 3 rd resin layer described later.

In the present embodiment, as described later, the end face 11E can be covered by plastically deforming the 2 nd resin layer 12 so as to be elongated. Therefore, the thickness of the 2 nd resin layer 12 (i.e., the thickness of the covering portion 14) on the end face 11E can be smaller than the average thickness of the 2 nd resin layer 12 on the one face 11A.

In embodiment 1, the end portion of the 1 st resin layer 11 may be inclined with respect to the one surface 11A, as shown in fig. 1. When the end face 11E is inclined with respect to the one face 11A, the thickness of the 1 st resin layer 11 becomes smaller toward the tip 11F. That is, the thickness of the end portion of the 1 st resin layer 11 may be smaller than the average thickness of the 1 st resin layer. In other words, the front end 11F of the 1 st resin layer 11 may be a shape with a thin front end. The end surface 11E may be an inclined surface inclined at an obtuse angle with respect to the one surface 11A. The end surface 11E need not be a flat surface, and may include a curved surface as appropriate. Similarly, the covering portion 14 may have an inclined surface.

The release film according to the present embodiment may be in a single sheet form or may be wound into a roll form (roll form). The release film in a single sheet form is used, for example, when a circuit board or the like in a sheet form is pressed by batch (batch) pressing, rapid pressing, or the like, as described later. The release film in a single sheet form has a polygonal shape (polygonal planar shape) in a plan view, and typically has a rectangular shape, a square shape, or the like, but may have a circular shape. Each end of the release film constituting each side (i.e., 4 sides if it is a square) is preferably constituted by the end face 11E having the covering portion 14 as described above. Since the release film in a single sheet form is generally pressed entirely by a pressing plate which is one turn larger than the release film, the coating portions 14 are provided at the end portions constituting the respective sides, whereby the bleeding of the 1 st resin layer 11 can be effectively prevented.

In the release film in a single sheet form, the entire end face of the 1 st resin layer 11 does not necessarily need to be covered, and may be partially covered. Specifically, when the outer edge of the release film is observed over the entire circumference in the direction perpendicular to the thickness direction, the coverage ratio calculated by the following equation is, for example, 30% or more, preferably 50% or more, more preferably 70% or more, and most preferably 100%, where "a 1" represents the area of the 1 st resin layer covered by the covering portion and "B1" represents the area of the portion where the 1 st resin layer is exposed.

Coating ratio is a1/(a1+ B1) × 100

Similarly, in the release film in a single piece, the end portions constituting the respective sides do not need to be all constituted by the end face 11E having the covering portion 14, and only the end portions constituting a part of the sides may be constituted by the end face 11E having the covering portion 14. When the planar shape of the release film is polygonal, the covering portion 14 is preferably provided on at least 2 sides. For example, in the square shape, the end portions constituting the opposite sides may be constituted by the end face 11E having the covering portion 14. Even with such a configuration, for example, when the release film is used in a system in which the entire release film is not pressed, bleeding of the resin constituting the 1 st resin layer 11 can be effectively prevented.

On the other hand, both side ends of the release film in a roll shape may be formed of end faces 11E having the covering portions 14. The release film in a roll shape is pressed while being conveyed by roll-to-roll, for example, but oozing occurs from both side ends at this time, and therefore oozing can be effectively prevented by providing the covering portions 14 at both side ends.

In the roll-shaped release film, both side ends are not necessarily entirely covered with the covering portion, but may be partially covered with the covering portion, but are preferably covered with a certain ratio or more. Specifically, when both side ends of the release film are observed in parallel to the TD direction, when the area of the 1 st resin layer covered by the covering portion is "a 2" and the area of the portion where the 1 st resin layer is exposed is "B2", the coverage ratio calculated by the following equation is, for example, 30% or more, preferably 50% or more, more preferably 70% or more, and most preferably 100%.

Coating ratio is a2/(a2+ B2) × 100

However, in the case where the release film in a roll shape is cut out and used in a single piece, a covering portion may be provided appropriately by any method described later at an end portion other than both side end portions after cutting out.

Next, an example of a method for manufacturing a release film according to the present embodiment will be described with reference to fig. 3. In the release film according to the present embodiment, first, a laminate 16 including a2 nd resin layer 12, a1 st resin layer 11, and a2 nd resin layer 13 is prepared. The method for producing the laminate 16 is not particularly limited, and examples thereof include a coextrusion method such as a water-cooled or air-cooled coextrusion blow molding method or a coextrusion T-die method, a method of laminating films by dry lamination, hot press molding or the like after producing films for constituting respective resin layers, an extrusion lamination method, a solvent casting method, and the like.

Next, the laminate 16 is cut to obtain the release film 10. During this cutting, the 2 nd resin layer 12 is deformed to form the covered portion 14. Here, the laminate 16 in the present embodiment can be cut by press cutting using the press blade 17 as shown in fig. 3. The press-cutting edge 17 may have an inclined surface 17A at the tip, and for example, a thomson blade may be used. In fig. 3, the inclined surface 17A is provided on both surfaces of the tip end of the press blade 17, but the inclined surface 17A may be provided on only one surface.

If the laminate 16 supported by the base 18 is cut by press cutting from the surface on the 2 nd resin layer 12 side by the press blade, for example, the end face 11E of the 1 st resin layer 11 formed by cutting becomes an inclined face along the shape of the inclined face 17A, and the 2 nd resin layer 12 extends to cover the end face 11E of the 1 st resin layer 11A, thereby forming the covered portion 14, as shown in fig. 3. Further, a release film in a roll shape can be also produced by winding up the laminate after the covering portion 14 is formed.

By the above method, the release film having the covering portion at the end portion can be manufactured in a simple process, and therefore, the release film with less bleeding can be easily manufactured.

< embodiment 2 >

Fig. 4 shows an end structure of the release film according to embodiment 2. The embodiment 2 is different from the embodiment 1 in the structure of the end portion of the release film. Specifically, in embodiment 1, the end faces are covered with one of the pair of 2 nd resin layers, but in this embodiment, the end faces are covered with both of the pair of 2 nd resin layers. That is, the pair of 2 nd resin layers form the coating portion.

Hereinafter, differences from embodiment 1 will be described with respect to the release film according to embodiment 2, and the same as embodiment 1 will be omitted.

In embodiment 2, the release film 20 includes a1 st resin layer 21 and 2 nd resin layers 22 and 23 provided on both surfaces 21A and 21B of the 1 st resin layer 21, respectively, and a covering portion 24 is provided on an end face 21E of the 1 st resin layer 21. In the embodiment shown in fig. 4, the end face 21E has an inclined face 21G and an inclined face 21H. In the present embodiment, the covering portion 24 is composed of both the 2 nd resin layers 22 and 23. That is, the 2 nd resin layers 22 and 23 cover the end surfaces of the 1 st resin layer 21, respectively. In the embodiment shown in fig. 4, the 2 nd resin layer 22 is coated with the 1 st resin layer 21 from the upper side of the one surface 21A of the 1 st resin layer 21 to the upper side of the end face 21E. Similarly, the 2 nd resin layer 23 is coated with the 1 st resin layer 21 from the other surface 21B to the end surface 21E of the 1 st resin layer 21. The 1 st and 2 nd resin layers 22 and 23 are preferably connected to the end face 21E.

In the present embodiment, the release film 20 is provided with the covering portion 24, and thus, even when heated and pressurized at the time of hot press working or the like, the resin constituting the 1 st resin layer 21 can be prevented from oozing out from the end face 21E.

The pair of 2 nd resin layers 22 and 23 are disposed so as to be connected to each other on the end face 21E, and as shown in fig. 4, the entire end face 21E is covered with the covering portion 24 in the cross section.

In the present embodiment, as described later, the end face 21E can be covered by plastically deforming the 2 nd resin layers 22 and 23 so as to be elongated. Therefore, the thickness of each of the 2 nd resin layers 22 and 23 on the end face 21E can be thinner than the average thickness of each of the 2 nd resin layers 22 and 23 on the one face 21A and the other face 21B.

In embodiment 2, the end portion of the 1 st resin layer 11 is formed to be tapered, but it may be: the tip 21F is disposed at a position between the two surfaces 21A and 21B in the thickness direction of the release film 30, and the tip 21F is connected to the surfaces 21A and 21B at an obtuse angle via inclined surfaces 21G and 21H constituting the end surface 21E. The inclined surfaces 21G and 21H do not necessarily have to be flat surfaces, and may include curved surfaces as appropriate.

Next, an example of a method for manufacturing a release film according to the present embodiment will be described. In the release film according to the present embodiment, first, a laminate 26 including a2 nd resin layer 22, a1 st resin layer 21, and a2 nd resin layer 23 is prepared. Next, the laminate 26 is cut to obtain the release film 20, and the covering portion 24 is formed by the 2 nd resin layers 22 and 23 by this cutting. Here, the laminate 20 in the present embodiment can be cut by press cutting using the cutting blade 27 as shown in fig. 5. The shear blade 27 is generally composed of an upper blade 27A and a lower blade 27B, and the shear force is applied to the stacked body 26 to cut the stacked body by bringing the upper blade 27A and the lower blade 27B close to each other in the thickness direction. By such cutting, the end face 21E of the 1 st resin layer 21 is formed into a shape with a narrow tip, and the 2 nd resin layers 22 and 23 are deformed so as to extend along the shape of the end face 21E, thereby forming a covered portion 24 covering the end face 21E as shown in fig. 4.

< embodiment 3 >

When the end surfaces of the 1 st resin layer are covered with the pair of 2 nd resin layers as described above, the structure is not limited to the structure of embodiment 2 described above, and various shapes may be provided, and for example, the structure of the release film 30 according to embodiment 3 shown in fig. 6 may be provided. The release film according to embodiment 3 below is described with respect to the points different from embodiment 2, and the points not described are the same as embodiment 2.

In the release film 30 according to embodiment 3, as shown in fig. 6, the 2 nd resin layers 32 and 33 protrude outward from the end face 31E. That is, the 2 nd resin layers 32 and 33 have the extending portions 32F and 33F, respectively. By the 2 nd resin layer having the protruding portion, the 1 st resin layer 31 is more difficult to ooze out of the release film. The lengths of the protruding portions 32F, 33F are preferably larger than the average thickness of each of the 2 nd resin layers 32, 33 having the respective protruding portions 32F, 33F. In addition, the protruding portions 32F, 33F may be engaged with each other. By the protruding portion engagement, the oozing can be more effectively prevented. Examples of the joining method include thermal welding, chemical welding, and joining with an adhesive. In the embodiment shown in fig. 6, the end face 31E has inclined surfaces 31G and 31H.

In the production of the release film 30 according to the present embodiment, first, a laminate 36 including the 2 nd resin layer 32, the 1 st resin layer 31, and the 2 nd resin layer 33 is prepared. Next, the laminate 36 is cut to obtain the release film 30, and the covering portion 34 is formed by this cutting. Here, the laminate 30 in the present embodiment can be cut by melt cutting using a heating blade 37 as shown in fig. 7. The 2 nd resin layers 32 and 33 are stretched while being melted to cover the end face 31E, thereby forming the covered portion 34. Further, if the fusion cutting is performed, the 2 nd resin layers 32 and 33 are fused to each other on the end face 31E. In addition, the end portion of the 1 st resin layer 31 is melted and stretched, and thus the shape of the tip thereof becomes more elongated. Not only the 1 st resin layer 31 but also the 2 nd resin layers 32 and 33 are easily stretched because they are cut while being melted, and the end face 31E of the 1 st resin layer 31 can be covered with the stretched 2 nd resin layers 32 and 33.

The heating blade 37 may be heated to a temperature at least enough to melt the 2 nd resin layers 32 and 33, and may be heated to a temperature higher by about 30 ℃ than the melting point of the resin used, preferably 5 to 20 ℃.

The heating blade 37 is a press blade, and specifically, a form of the press blade having the inclined surface 37A at the tip is shown, but a form other than the press blade may be used.

In the above embodiments 1 to 3, the covering portion is formed on the end face of the 1 st resin layer by press cutting, shear cutting, and melt cutting, but the covering portion may be formed by other cutting methods.

In the shear cutting and the melt cutting described in embodiments 2 and 3, the coating portion is formed by the pair of 2 nd resin layers provided on both surfaces of the 1 st resin layer. However, when the coating portion is formed by these cutting methods, the coating portion may be formed by only one 2 nd resin layer as in embodiment 1 by appropriately selecting the kind of resin constituting the 2 nd resin layer or by appropriately selecting the cutting conditions.

In addition, although the embodiments 2 and 3 show the mode in which the 2 nd resin layers 22 and 23 (or 32 and 33) are connected to each other at the end face 21E (or 31E), they may not be connected to each other, or a portion not covered with a covering portion may be present at the end face, as in the modification (see fig. 2) of the embodiment 1. The 2 nd resin layers 22 and 23 (or 32 and 33) may not be in direct contact with each other, and may be connected to each other through a member other than the 1 st resin layer, such as a 3 rd resin layer described later. Further, a space may be present between the covering portion and the end face.

The end surfaces 11E, 21E, and 31E of embodiments 1 to 3 do not necessarily have a tapered shape. For example, in embodiment 2 described above, the 2 inclined surfaces 21G and 21H constituting the end surface 21E are each connected to the one surface 21A and the other surface 21B at an obtuse angle, but these inclined surfaces 21G and 21H may be connected to the one surface 21A and the other surface 21B at an acute angle. That is, the end face 21E of the 1 st resin layer 21 may have a shape recessed inward, and the covering portion 24 may have a shape recessed inward. The end portion of this embodiment can be formed, for example, by pressing a cutting blade against the end face of the 1 st resin layer when the release film is cut.

In addition, the case where the end face of the 1 st resin layer is formed in a recessed shape can also be applied to the case where the covered portion is formed only by one 2 nd resin layer 12 as in embodiment 1, and in this case, the covered portion can also be formed by pressing the press blade against the end face of the 1 st resin layer at the time of cutting the release film.

The end faces 11E, 21E, and 31E in the above embodiments 1 to 3 have inclined faces, but the inclined faces are not necessarily required, and may be formed of, for example, vertical faces parallel to the thickness direction. The vertical surface and the inclined surface may be combined, or may have other shapes.

< embodiment 4 >

In the above embodiments 1 to 3, the covering portion is formed by cutting at the time of manufacturing the release film, but the covering portion may be formed by a method other than cutting.

A specific example thereof will be described as embodiment 4 with reference to fig. 8. Hereinafter, differences from embodiment 2 will be described with respect to the release film according to embodiment 4, and the same as embodiment 2 will be omitted.

In the present embodiment, the release film 40 includes a1 st resin layer 41 and 2 nd resin layers 42 and 43 provided on both surfaces 41A and 41B of the 1 st resin layer 41, respectively. In the present embodiment, the 2 nd resin layers 42 and 43 have the extending portions 42F and 43F, respectively, as in the 3 rd embodiment. The release film 40 has a pressure-bonding section 48 in which the protruding sections 42F, 43F are pressed and joined to each other. The thickness of the pressure-bonding section 48 is thinner by the compressive deformation, and therefore is smaller (thinner) than the sum of the average thicknesses of the 2 nd resin layers 42 and 43.

In the present embodiment, the release film 40 is provided with the covering portion 44, and thus, even when heated and pressurized at the time of hot press working or the like, the resin constituting the 1 st resin layer 41 can be prevented from oozing out from the end face 41E. In addition, since the 2 nd resin layers 42 and 43 are joined to each other, bleeding can be more reliably prevented.

Next, an example of a method for manufacturing the release film 40 according to the present embodiment will be described with reference to fig. 9. In the present embodiment, as shown in fig. 9, similarly to the above embodiments, a laminate 46 in which the 2 nd resin layer 43, the 1 st resin layer 41, and the 2 nd resin layer 42 are laminated in this order is prepared. In this case, the 1 st resin layer 41 is intermittently provided in the laminate 46, and a region 46A where the 1 st resin layer 41 is not provided is provided between the 2 nd resin layers 42 and 43. That is, in the laminate 46, the plurality of 1 st resin layers 41 may be arranged along the plane direction.

Next, in the region 46A where the 1 st resin layer 41 is not provided, the 1 st and 2 nd resin layers 42 and 43 are pressed so as to be in contact with each other, and are pressed by heating or the like to form the pressure-bonded section 48, whereby the covered section 44 is also formed. In addition, through the above steps, the protruding portions 42F, 43F are provided, and the protruding portions 42F, 43F are fixed to each other. Then, the laminated body 46 may be cut along the pressure-bonding section 48 or the like as necessary to obtain a plurality of release films 40. In fig. 9, a broken line indicates a cutting line.

< embodiment 5 >

In the above embodiment 4, the 1 st resin layer is not provided in the pressure-bonding section, but the 1 st resin layer may be provided in the pressure-bonding section. A specific example thereof will be described as embodiment 5 with reference to fig. 10. In the following description, differences from embodiment 4 will be described with respect to the release film according to embodiment 5, and the same as embodiment 4 will be omitted.

In the present embodiment, the release film 50 includes a1 st resin layer 51 and 2 nd resin layers 52 and 53 provided on both surfaces 51A and 51B of the 1 st resin layer 51, respectively. In the present embodiment, the 1 st resin layer 51 has the protruding portion 51F, similarly to the 2 nd resin layers 52 and 53. The protruding portions 51F, 52F, 53F have pressure-bonding portions 58 that are pressed and joined to each other. The crimping portion 58 forms a part of the covering portion 54. The thickness of the pressure-bonding section 58 becomes thinner by the compressive deformation, and therefore is thinner than the sum of the average thicknesses of the 2 nd resin layers 52, 53 and the 1 st resin layer 51.

With the above configuration, the end face 51E of the 1 st resin layer 51 is covered with the covering portion 54. Therefore, in the present embodiment, the resin constituting the 1 st resin layer 51 can be prevented from oozing out of the end face 51E of the 1 st resin layer 51.

Next, an example of a method for manufacturing the release film 50 according to the present embodiment will be described with reference to fig. 11. In the present embodiment, as shown in fig. 11, a laminate 56 in which a2 nd resin layer 53, a1 st resin layer 51, and a2 nd resin layer 52 are laminated in this order is prepared, as in the above-described embodiment 1. Next, the laminate 56 is partially compressively deformed by the pressure bonding means 57 such as a heated emboss roller, and the 1 st resin layer 51 and the 2 nd resin layers 52 and 53 are partially pressure bonded to form a pressure bonded section 58. Then, the laminate 56 can be cut along the pressure bonded part 58 or the like to obtain the release film 50. The cut line in the production of the release film shown in fig. 10 is indicated by a broken line. The cutting position in the production of the release film 50 may not be on the pressure-bonding section 58, and may be a position shown by a chain line in fig. 11. Fig. 12 shows a cross-sectional view of the release film 50 obtained in this case.

In this manner, the bleeding of the 1 st resin layer 51 can be suppressed. In addition, in this manufacturing method, since it is not necessary to match the cutting position with the pressure-bonding section 58, the manufacturing becomes easier. For example, when the laminate 56 is pressed and pressed by embossing while being conveyed by roll-to-roll processing, cutting or the like may be performed in parallel with the embossing.

In the above-described embodiments 4 and 5 (see fig. 8 to 12), the end faces 41E and 51E of the 1 st resin layers 41 and 51 are preferably deformed during pressure bonding, for example, so as to have inclined faces 41G, 41H, 51G, and 51H.

However, the end faces 41E, 51E do not necessarily have to have the inclined faces 41G, 41H, 51G, 51H, and may be formed of, for example, a vertical face (a face parallel to the thickness direction). In the case of being formed by a vertical surface, a space may exist between the covering portion formed by pressure-bonding the 2 nd resin layer and the end surface. However, even if there is a space, the resin constituting the 1 st resin layer can be appropriately prevented from bleeding out.

In the above-described embodiment 4 (see fig. 9), the 2 nd and 3 rd resin layers 42 and 43 are bonded to each other by pressure bonding, but may be configured by a method other than pressure bonding, may be bonded by welding, or may be bonded using an adhesive or the like.

Similarly, in the above-described embodiment 5 (see fig. 11), the 1 st resin layer 51, the 2 nd and 3 rd resin layers 52 and 53 are bonded to each other by pressure bonding, but may be bonded by a method other than pressure bonding, for example, by welding.

< embodiment 6 >

In the above embodiments 1 to 5, the covering portion covering the end face of the 1 st resin layer is formed of the 2 nd resin layer, but the covering portion may be formed of a covering member other than the 2 nd resin layer. Hereinafter, such a structure will be described as release films 60 and 70 according to embodiments 6 and 7.

Hereinafter, differences from embodiment 1 will be described with reference to fig. 13 with respect to the release film according to embodiment 6, and the same as embodiment 1 will be omitted.

The "other member" means a member other than the 2 nd resin layer when the laminate constituting the release film is composed of the 1 st and 2 nd resin layers, but means a member other than the other resin layers when another resin layer other than the 1 st and 2 nd resin layers constituting the laminate such as the 3 rd resin layer described later is provided. However, the members other than the other resin layers, such as the 3 rd resin layer, may have the same resin composition as the other resin layers.

In embodiment 6, the release film 60 includes a1 st resin layer 61 and 2 nd resin layers 62 and 63 provided on both surfaces 61A and 61B of the 1 st resin layer 61, respectively. In the present embodiment, the covering portion 64 covering the end face 61E of the 1 st resin layer 61 is formed of a covering member. The covering member may be a resin film, for example. The covering portion 64 may have any structure as long as it can cover the end face 61E, and may cover all of the outer surface of the 2 nd resin layer 62, the end face of the 1 st resin layer, and the outer surface of the 2 nd resin layer 63, for example. The covering portion 64 may be bonded to the outer surfaces of the 2 nd resin layers 62 and 63 with an adhesive, or may be bonded by welding, pressure bonding, or the like. The covering portion 64 may be formed using a plurality of covering members.

In embodiment 6, the release film 60 includes the covering portion 64, and thus bleeding of the resin constituting the 1 st resin layer 61 can be effectively prevented.

The resin film constituting the covering portion 64 may be a known resin film, and a resin film having a higher flow starting temperature and a higher storage modulus than the 1 st resin layer 61 may be used.

As the resin constituting the resin film, specifically, the resin shown as the resin that can be used in the 2 nd resin layer as described above may be appropriately selected and used, and for example, a polyester-based resin, a polyolefin-based resin, a polystyrene-based resin, or the like may be used, and a thermoplastic resin or a rubber component may be appropriately added to these resins and used. The details of these resins are as described in the 2 nd resin layer.

The thickness of the resin film is not particularly limited, and is, for example, 1 to 250 μm, preferably 5 to 150 μm.

In manufacturing the release film 60 according to the present embodiment, first, a laminate including the 1 st resin layer 61 and the 2 nd resin layers 62 and 63 is prepared, and a member for covering (for example, a resin film) is prepared, as in the above embodiments. Then, a covering member (resin film) is attached to the end of the laminate, thereby obtaining a release film 60.

< 7 th embodiment >

Next, a release film 70 according to embodiment 7 of the present invention will be described.

Fig. 14 shows an end structure of a release film 70 according to embodiment 7. In the present embodiment, the release film 70 includes a1 st resin layer 71 and 2 nd resin layers 72 and 73 provided on both surfaces 71A and 71B of the 1 st resin layer 71, respectively. In the present embodiment, the covering portion 74 covering the end face 71E of the 1 st resin layer 71 is formed of a covering member, and the covering member is a sealing material (sealant). The release film 70 is provided with the covering portion 74 formed of a covering member (sealant), and thus the bleeding of the resin constituting the 1 st resin layer 71 can be effectively prevented.

As shown in fig. 14, the covering portion 74 formed of the sealant may be laminated on the end faces 72E and 73E of the 2 nd resin layers 72 and 73 in addition to the 1 st resin layer 71. By laminating the sealant layers also on the end faces 72E and 73 of the 2 nd resin layers 72 and 73, the resin constituting the 1 st resin layer 71 can be more reliably prevented from oozing out of the end face 71E.

Similarly to the above embodiments, the release film 70 can be produced by first preparing a laminate having the 1 st resin layer 71 and the 2 nd resin layers 72 and 73, and then applying a sealant to the end of the laminate to form the covered portion 75.

The sealant constituting the covering portion 74 is not particularly limited, and epoxy resin, urethane resin, silicone resin, phenol resin, polyimide resin, or the like can be used. The thickness of the coating portion 74 is, for example, 1 to 1000 μm, preferably 10 to 500 μm.

The covering portion made of the covering member exemplified in embodiments 6 and 7 is not limited to the resin film or the sealant as long as it can cover the end face of the 1 st resin layer. In embodiments 6 and 7, the covering portion covers not only the end face of the 1 st resin layer but also the end face of the 2 nd resin layer, but the covering portion does not necessarily cover the end face of the 2 nd resin layer as long as it covers the end face of the 1 st resin layer. For example, the covering portion 74 formed by the sealant layer shown in embodiment 7 may cover only the end face of the 1 st resin layer.

< embodiment 8 >

While the above embodiments 1 to 7 show a structure in which the end face of the 1 st resin layer is covered with the covering portion, the end face of the 1 st resin layer is not necessarily covered with the covering portion, and the release film according to embodiment 8 has a structure in which the end portion of the 2 nd resin layer is disposed to protrude outward beyond the end face of the 1 st resin layer.

Hereinafter, a release film 80 according to embodiment 8 will be described with reference to fig. 15, which is different from embodiment 1. Note that points for which description is omitted are the same as those in embodiment 1.

The release film 80 according to embodiment 8 includes a1 st resin layer 81 and 2 nd resin layers 82 and 83 provided on both surfaces 81A and 81B of the 1 st resin layer 81, respectively. In the present embodiment, both end portions of the 2 nd resin layers 82 and 83 are disposed to protrude outward beyond the end face 81E of the 1 st resin layer 81, and constitute protruding portions 82E and 83E.

According to this aspect, when the release film 80 is used for hot pressing, even if the resin constituting the 1 st resin layer 81 flows due to the hot pressing, the flowing resin remains between the protruding portions 82E, 83E, and thus the release film 80 can be prevented from leaking out from the outer edge thereof to the outside.

Here, the projecting length L1 of the 2 nd resin layers 82 and 83 may be a length that allows the resin of the 1 st resin layer 81 to remain between the projecting portions 82E and 83E even if the resin flows by hot pressing, and prevents the resin from appropriately leaking out from the outer edge of the release film 80. The extension length L1 is not particularly limited, and is, for example, 5 to 50mm, preferably 10 to 30 mm. The protruding length of the 2 nd resin layer 82 and the protruding length of the 2 nd resin layer 83 may be different.

The release film 80 according to the present embodiment can be manufactured by preparing a resin film for forming the 1 st resin layer 81 and the 2 nd and 3 rd resin films for forming the 2 nd resin layers 82 and 83, and joining and laminating them by heating and pressure bonding or the like. In this case, resin films one step larger than the 1 st resin film may be prepared as the 2 nd and 3 rd resin films. The release film of the present embodiment can be produced by merely heating and pressure bonding the resin film as described above, and thus the production method thereof is easy.

When the release film 80 in the present embodiment is, for example, a single sheet, it is typically a rectangle, a square, or the like, and the protruding portions 82E and 83E may be provided at the end portions of the release film constituting each side (i.e., 4 sides) as described above. However, as in the covering portions shown in embodiments 1 to 7, it is not necessary to provide all of the end portions of the sides constituting the release film 80 with the extending portions. When the planar shape of the release film is polygonal, it is preferable that at least 2 sides or more of the release film are provided with the protruding portion.

When the release film 80 is in the form of a roll, the protruding portions 82E and 83E may be provided at both side ends, as in the case of the covering portion described above.

The extending portions 82E and 83E at the respective ends of the release film 80 according to the present embodiment can be fixed to each other by fixing means (not shown) such as a fixing member, an adhesive, welding, or pressure bonding. If the protruding portions 82E, 83E are fixed to each other, the 1 st resin layer 81 is sandwiched by the 2 nd resin layers 82, 83 from above and below by the fixation, and the laminated structure is further stabilized.

Further, by fixing the extension portions 82E, 83E to each other, as shown in fig. 16, a covering portion 84 covering the end face 81E can be formed by the extension portions 82E, 83E. At this time, as shown in fig. 16, the covering portion 84 may be disposed at least partially across the space 88 with respect to the end surface 81E, but the space 88 may be absent. In this case, the release film 80 has a space between the 1 st resin layer 81 and a fixing portion where the extending portions 82E and 83E of the 2 nd resin layer are fixed to each other.

In addition, the fixing by the fixing means may be performed by fixing the end portions constituting the respective sides (4 sides if the side is a quadrangle) by the fixing means in a single-piece release film such as a quadrangle, but it is not necessary to fix the end portions constituting all the sides. Even if the respective end portions constituting all the sides are not fixed, for example, by fixing the end portions constituting the opposing 2 sides by fixing means, the 1 st resin layer 81 can be appropriately sandwiched by the 2 nd resin layers 82 and 83 by the fixing.

In addition, when the 1 st resin layer 81 is sandwiched between the 2 nd resin layers 82 and 83 by the fixing means as described above, it is not necessary to join the 2 nd resin layers 82 and 83 to the two surfaces 81A and 81B of the 1 st resin layer 81, respectively. Therefore, in the production of the release film 80, it is not necessary to bond the resin films by pressure bonding or the like. That is, since the release film 80 can be manufactured by stacking 3 resin films and fixing the protruding portion by the fixing means, the manufacturing method is simple and the release film can be easily manufactured without introducing a large-scale manufacturing apparatus.

In the present embodiment, the 2 nd resin layers 82 and 83 are arranged so that both ends thereof protrude outward beyond the end face 81E of the 1 st resin layer 81 to form protruding portions 82E and 83E, but the protruding portions may have different lengths. That is, the extension portion 82E may be longer than the extension portion 83E, and the extension portion 82E may be shorter than the extension portion 83E.

< embodiment 9 >

Fig. 17 shows an end structure of a release film according to embodiment 9. Hereinafter, differences from embodiment 1 will be described with respect to the release film 90 according to embodiment 9, and the same as embodiment 1 will be omitted.

The release film 90 according to embodiment 9 includes a1 st resin layer 91 and 2 nd resin layers 92 and 93 provided on both surfaces 91A and 91B of the 1 st resin layer 91, respectively. In the present embodiment, the release film 90 has a folded portion 98. That is, the release film has a structure in which the end portion is folded back (folded back) toward the inside of the release film. Therefore, the end face 91E of the 1 st resin layer 91 is located more inward than the outer edge 90E of the release film 90. The end face 91E of the 1 st resin layer 91 faces inward from the outer edge 90E of the release film 90. In the folded portion 98, one 2 nd resin layer 92 is disposed on the outer peripheral side, and the other 2 nd resin layer 93 is disposed on the inner peripheral side. According to this aspect, even if the resin constituting the 1 st resin layer 91 flows due to hot pressing, the resin does not immediately flow out to the outside of the outer edge 90E of the release film 90, and therefore the resin can be prevented from oozing out from the outer edge of the release film 90.

As shown in fig. 17, in the release film 90, the outer surfaces of the 2 nd resin layer 93 are in contact with each other in the folded portion 98, and they can be fixed by fixing means such as bonding with an adhesive, welding, pressure bonding, or a fixing tool. The release film 90 can easily maintain the state in which the end portions are folded back by fixing the outer surfaces of the 2 nd resin layer 93 to each other.

The release film 90 can be formed by, for example, folding back the end of a laminate composed of the 1 st resin layer 91 and the 2 nd resin layers 92 and 93. In the present embodiment, the folded portion has a gently curved surface shape, but may be flattened. The thickness of the folded portion may be less than the average thickness of the release film.

In the present embodiment, the folded length L2 (i.e., the length from the outer edge 90E of the release film 90 to the end face 91E of the 1 st resin layer 91) may be a length that is sufficient to remain inside the outer edge 90E of the release film 90 even if the resin constituting the 1 st resin layer 91 flows out from the end face 91E of the resin layer 91 by hot pressing. The length L2 is not particularly limited, but is, for example, 1 to 50mm, preferably 5 to 30 mm.

In addition, when the release film 90 in the present embodiment is, for example, a single sheet, it is typically a rectangle, a square, or the like, and may have a folded portion at each end of the release film constituting each side (i.e., 4 sides). However, it is not necessary that all the end portions of the respective sides constituting the release film 90 have the folded portions. For example, when the planar shape of the release film is polygonal, it is preferable that at least 2 sides have the folded portion. When the release film 90 is in the form of a roll, the both side ends may have folded portions, as in the case of the covering portion.

< other modification example >

The release films according to embodiments 1 to 9 described above have the 2 nd resin layers provided on both surfaces of the 1 st resin layer, but the 2 nd resin layer may be provided on only one surface of the 1 st resin layer. Fig. 18 shows a specific example thereof. Fig. 18 shows a modification of embodiment 1, and a release film 10 includes a1 st resin layer 11 and a2 nd resin layer 12 provided only on one surface 11A of the 1 st resin layer 11. In this modification, the covering portion 14 is formed of the 2 nd resin layer 12 as in embodiment 1. The structure of the covering portion 14 is as described in embodiment 1, but the 2 nd resin layer 13 is not provided on the other surface 11B. Therefore, the covered portion 14 formed of the 2 nd resin layer 12 does not contact with the resin layer (2 nd resin layer) provided on the other surface 11B.

Similarly, in embodiments 2 to 3, the 2 nd resin layer may be provided only on one surface of the 1 st resin layer, and in this case, the covering portion may be formed of only one 2 nd resin layer. In embodiments 6 to 9, one of the pair of 2 nd resin layers may be omitted.

Fig. 19 shows a modification of embodiment 9 in which a2 nd resin layer is provided only on one surface of a1 st resin layer. In the present modification, the 2 nd resin layer 92 is disposed on the outer peripheral side in the folded portion. In the release film 90 according to embodiment 9 (see fig. 17), the outer surfaces of the 2 nd resin layer are in contact with each other, but in the present modification (see fig. 19), the other surfaces 91B of the 1 st resin layer 91 may be in contact with each other, and the other surfaces 91B may be fixed to each other by fixing means such as bonding with an adhesive, welding, pressure welding, or a fixing tool.

In embodiments 1 to 3 and 6 to 9, the method for producing a release film in the case where the 2 nd resin layer 13 is provided on only one surface is the same as that described in the embodiments except that one of the 2 nd resin layers is omitted in the prepared laminate.

In addition, in each embodiment, a 3 rd resin layer may be provided between the 1 st resin layer and the 2 nd resin layer. The 3 rd resin layer preferably has a function as a bonding layer for bonding the 1 st resin layer and the 2 nd resin layer. Fig. 20 shows a modification of embodiment 1 as an example of a structure in which the 3 rd resin layers 19A and 19B are provided. Fig. 20 shows a mode in which one 2 nd resin layer 12 is connected to the other 2 nd resin layer 13 via the 3 rd resin layer 19B, but when the 3 rd resin layer is provided, the 2 nd resin layers 12 and 13 may be in direct contact with each other. Of course, the 2 nd resin layers 12 and 13 may not be connected to each other, and a part of the end face 11E may not be covered with the covering portion 14.

In embodiments 1 to 6, the 3 rd resin layer may or may not form a coating portion together with the 2 nd resin layer as shown in fig. 20.

The resin constituting the 3 rd resin layer may be any resin as long as it can exert its function, and for example, it may contain a resin constituting the main component of the 1 st resin layer and a resin constituting the main component of the 2 nd resin layer in contact with the 3 rd resin layer. Therefore, the 3 rd resin layer preferably contains a polyolefin-based resin other than the polymethylpentene-based resin, and at least 1 selected from the polyester-based resin and the polymethylpentene-based resin. The 3 rd resin layer may contain other thermoplastic resin and rubber components. Details of these resin, thermoplastic resin, and rubber components are as described in the 1 st and 2 nd resin layers.

The thickness of each of the 3 rd resin layers is, for example, 5 to 50 μm, preferably 10 to 30 μm.

Here, in the case where the 2 nd resin layers are provided on both surfaces of the 1 st resin layer, the 3 rd resin layer may be provided only between the 1 st resin layer and one of the 2 nd resin layers, but is preferably provided between the 1 st resin layer and each of the two 2 nd resin layers as shown in fig. 20. In this way, the release film can bond the 2 nd resin layer to the 1 st resin layer with a high bonding force by providing the 3 rd resin layer.

In the release film of the present invention, by providing each of the above-described aspects, the resin constituting the 1 st resin layer is less likely to bleed out to the outside of the release film by heating and pressurizing. Specifically, the release film of the present invention has a temperature of 170 ℃ for 30 minutes and a kgf/cm of 30²The amount of bleeding of the 1 st resin layer when pressed under the pressure of (3) is preferably 1.5mm or less, more preferably 1.3mm or less. When the amount of bleeding is not more than the above upper limit, for example, contamination of auxiliary materials such as circuit boards, press plates, and cushioning materials can be effectively prevented.

The bleeding amount is a bleeding length of the resin constituting the 1 st resin layer based on the outer edge of the release film when heated and pressurized under the above-mentioned pressing conditions, and the maximum value of the bleeding length is adopted.

< method for using release film >

The release film of the present invention can be suitably used, for example, in the production of a circuit board such as an FPC. The circuit substrate may be manufactured by: a core substrate, a cover film and a release film are prepared, and the core substrate and the cover film are integrated by hot pressing using the release film. Hereinafter, a method of manufacturing the circuit board will be described in detail.

The core substrate includes a base material made of polyimide resin, polyester resin, liquid crystal polymer, or the like, and a circuit portion formed of a conductive material such as copper on the base material. The circuit portion may be provided on one surface of the base material, or may be provided on both surfaces.

The cover film includes a base film and an adhesive layer provided on one surface of the base film. Examples of the substrate film include polyimide resin films, polyester resin films, and liquid crystal polymers. The adhesive layer is made of an epoxy adhesive, an acrylic adhesive, or the like.

The release film of the present invention described above can be used by appropriately selecting it. As described later, a pair of release films may have the same or different structures. In addition, the release film of the present invention described above may be used for one of the release films, but the release film of the present invention described above is preferably used for both of the release films.

In the present manufacturing method, the core substrate, the cover film, and the release film may be stacked. In this case, the cover film may be stacked on the core substrate so that the surface on which the adhesive layer is provided faces the core substrate. Further, since the cover film can be stacked on the surface of the core substrate on which the circuit portion is provided, the cover film can be stacked on both surfaces of the substrate when the circuit portion is provided on both surfaces of the substrate, and the cover film can be stacked on one surface of the substrate when the circuit portion is provided on one surface of the substrate.

The release films may be respectively stacked on both surfaces of the core substrate, and when the cover film is stacked on the core substrate, the release films may be stacked outside the cover film.

Therefore, specifically, the overlapping may be performed in the order of release film/cover film/core substrate/release film, or release film/cover film/core substrate/cover film/release film.

Next, as described above, the laminate of the core substrate, the cover film and the release film, which is stacked, is heated and pressed by using a platen, and the cover film is bonded and integrated with an adhesive layer on one surface or both surfaces of the core substrate, thereby obtaining a circuit board. Further, the release film can be peeled from the resulting circuit substrate.

The laminate may be heated and pressed by sandwiching the pair of press plates, or a buffer material may be appropriately provided between the release film and the press plates. Examples of the cushioning material include glass cloth, paper, PVC film, polyester film, and polyolefin film.

The release film of the present invention is difficult to bleed out the resin constituting the 1 st resin layer to the outside of the release film even if heated and pressurized by heat pressing as described above. Therefore, in the heating and pressing, the circuit portion, the cushioning material, the platen, and the like can be prevented from being contaminated by the release film.

As described above, the release film may be provided with the 2 nd resin layer only on one surface. In this case, the surface on which the 2 nd resin layer is provided may be directed to either the core substrate side or the platen side, but is preferably directed to the core substrate side in order to prevent contamination of the circuit portion.

The circuit board may be manufactured by batch (batch) pressing or rapid pressing, or by roll-to-roll pressing. In the case of using intermittent pressing or rapid pressing, the core substrate, the cover film, and the release film may be prepared in a single piece, and they are stacked and pressed to manufacture the circuit substrate.

In the case of roll-to-roll, the core substrate, the cover film, and the release film, which are wound in a roll shape, may be fed in a sheet form and stacked, and the core substrate and the cover film may be integrated by hot pressing using a platen between the rolls to manufacture the circuit board. The release film may be a film obtained by transferring and peeling the circuit board between rollers.

As a modification of embodiment 8, an example of a method for manufacturing a circuit board is shown. In embodiment 8, the release film is an integrated film including a1 st resin layer and 2 nd resin layers 82 and 83 provided on both surfaces of the 1 st resin layer. On the other hand, instead of integrating the resin layers, resin films may be prepared separately and laminated in the order of the 2 nd resin layer (one 2 nd resin film), the 1 st resin layer (1 st resin film), and the 2 nd resin layer (the other 2 nd resin film) in the pressing. In this case, by making the size of the 2 nd resin film larger than the 1 st resin film and providing the 2 nd resin film with the projecting portion, it is possible to prevent the resin constituting the 1 st resin film from oozing out to contaminate the surroundings. That is, the method for manufacturing a circuit board disclosed herein includes a laminating step of laminating a1 st resin film having a smaller size than a2 nd resin film on a2 nd resin film, and further laminating a2 nd resin film having a larger size than the 1 st resin film. By performing pressing after such a lamination process, a circuit board can be manufactured. The resin films used in the method for manufacturing a circuit board described here can have the same configuration as the resin layers included in the release film according to embodiment 8.

The method of using the release film described above is only an example, and the release film may be used in other forms, for example, as a release film used in manufacturing products other than circuit boards by heating and pressing using a platen.

Claims (12)

1. A method for manufacturing a release film,

comprises a step of forming a coating portion,

the covering section covers at least a part of an end face of the 1 st resin layer of a laminate including the 1 st resin layer and the 2 nd resin layer.

2. The method for manufacturing a release film according to claim 1,

comprises a step of cutting the laminated body,

the coated portion is formed by covering at least a part of the end face of the 1 st resin layer with the 2 nd resin layer by the cutting.

3. The method for manufacturing a release film according to claim 2,

the cutting is performed by at least one of press cutting, shear cutting and melt cutting.

4. The method for manufacturing a release film according to claim 1,

the covering part is formed by using a covering member.

5. The method for manufacturing a release film according to claim 1,

a projecting portion projecting outward beyond an end face of the 1 st resin layer is provided on the 2 nd resin layer,

fixing the protruding parts to each other.

6. The method for manufacturing a release film according to claim 5,

the extensions are secured to each other by at least one of a fastener, an adhesive, a fusion splice, and a crimp.

7. A method for manufacturing a release film,

comprises the following steps:

the end of the laminate provided with the 1 st resin layer and the 2 nd resin layer is folded back inward to form a folded-back portion.

8. The method for manufacturing a release film according to claim 7,

the folded-back portion is fixed by at least one of a fixing member, an adhesive, welding, and crimping.

9. A method for manufacturing a circuit board is provided,

the circuit substrate is manufactured by using the release film,

the release film comprises a1 st resin layer and a2 nd resin layer, and has a covering part for covering the end face of the 1 st resin layer,

the 2 nd resin layer is provided on at least one surface side of the 1 st resin layer, and has a composition different from that of the 1 st resin layer.

10. A method for manufacturing a circuit board is provided,

the circuit substrate is manufactured by using the release film,

the release film is provided with a1 st resin layer and a2 nd resin layer,

the 2 nd resin layer is provided on at least one surface side of the 1 st resin layer and has a composition different from that of the 1 st resin layer,

the 2 nd resin layer has a protruding portion protruding outward from an end face of the 1 st resin layer.

11. A method for manufacturing a circuit board is provided,

the circuit substrate is manufactured by using the release film,

the release film is provided with a1 st resin layer and a2 nd resin layer and a folding part,

the 2 nd resin layer is provided on at least one surface side of the 1 st resin layer, and has a composition different from that of the 1 st resin layer.

12. A method for manufacturing a circuit board is provided,

preparing a1 st resin layer and a2 nd resin layer having a different composition from the 1 st resin layer,

the manufacturing method comprises a laminating step of laminating a1 st resin layer having a smaller size than the 2 nd resin layer and a2 nd resin layer having a larger size than the 1 st resin layer on the 2 nd resin layer,

the lamination process is followed by pressing.

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