JP2022042971A - Release film, release film manufacturing method, and circuit board manufacturing method - Google Patents

Abstract

To prevent a resin from oozing from a specific resin layer by forming a film end into a specific structure.SOLUTION: A release film 10 includes a first resin layer 11, and a second resin layer 12 that is provided on at least one surface 11A side of the first resin layer 11 and has a composition different from the first resin layer 11, and has a coating part 14 coating an end face 11E of the first resin layer 11.SELECTED DRAWING: Figure 1

Description

The present invention relates to a release film, a method for manufacturing the same, and a method for manufacturing a circuit board.

Conventionally, when manufacturing a circuit board such as an FPC (flexible printed circuit board), it is common to perform a heat pressing process. In the hot press process, a release film is used to prevent the circuit board from adhering to the hot press plate. The release film is required to have performance such as heat resistance that can withstand hot press molding, mold release property for FPC and hot press plate, non-staining property for copper circuit, and ease of disposal.

In recent years, the L / S (line space) of the FPC has been made thinner, and along with this, the required quality for the release film has also increased, and in particular, the improvement of the unevenness followability has been required. The release film may have a multi-layer structure and a highly flexible material may be used for any one layer in order to improve the unevenness followability. Specifically, it is common to provide a surface layer and an intermediate layer and use a highly flexible material for the intermediate layer. Further, it is known that a polyolefin-based resin such as polyethylene (PE) or an ethylene-methylmethacrylate copolymer (EMMA) is used as a highly flexible material used for an intermediate layer or the like (for example, Patent Documents). 1).

Japanese Unexamined Patent Publication No. 2007-98816

However, highly flexible resins such as PE and EMMA have a low melting point and may melt or flow during pressing and may seep out from the end of the film. The exuded resin may adhere to the circuit board, the press plate, and auxiliary materials such as the cushion material arranged inside the press plate, and cause contamination.

Therefore, it is an object of the present invention to provide a release film capable of preventing exudation from a specific resin layer such as an intermediate layer generated when heat-pressed. Another object of the present invention is to provide a method for manufacturing a circuit board that is less likely to cause contamination.

As a result of diligent studies, the present inventor has made a release film having a multi-layer structure with a specific structure at the end of the film, or manufactured a circuit board using a release film having a specific structure or the like. We have found that the above problems can be solved, and completed the following invention. That is, the present invention provides the following [1] to [36].
[1] A first resin layer and a second resin layer provided on at least one surface side of the first resin layer and having a composition different from that of the first resin layer are provided.
A release film having a covering portion that covers the end face of the first resin layer.
[2] The release film according to the above [1], wherein the second resin layer forms the covering portion.
[3] The second resin layer is provided on both sides of the first resin layer.
The release film according to the above [2], wherein each of the second resin layers forms the covering portion.
[4] The second resin layer provided on one surface and forming a covering portion is connected to the second resin layer on the other surface side of the first resin layer. The release film according to [3].
[5] The second resin layer is provided on both sides of the first resin layer.
The release film according to any one of the above [2] to [4], wherein each of the second resin layers has an overhanging portion extending outward from the end face of the first resin layer.
[6] The release film according to the above [5], wherein the length of the overhanging portion is larger than the average thickness of the second resin layer.
[7] The release film according to the above [5] or [6], wherein the overhanging portions are adhered to each other.
[8] The release film according to the above [7], which has a crimping portion in which the overhanging portions are pressed against each other and adhered to each other.
[9] The release film according to the above [8], wherein the thickness of the crimping portion is smaller than the sum of the average thicknesses of the respective second resin layers.
[10] The release film according to the above [1], wherein the covering portion is formed of a covering member.
[11] The release film according to the above [10], wherein the covering member is a resin film.
[12] The release film according to the above [10], wherein the coating member is a sealing agent.
[13] The release film according to any one of [1] to [12] above, wherein the planar shape is polygonal and covering portions are provided on at least two or more sides thereof.
[14] The release film according to any one of the above [1] to [13], wherein the covering portion has an inclined surface.
[15] The release film according to any one of [1] to [14] above, further comprising a third resin layer provided between the first resin layer and the second resin layer.
[16] A first resin layer and a second resin layer provided on at least one surface side of the first resin layer and having a composition different from that of the first resin layer are provided.
A release film having a projecting portion in which the second resin layer projects outward from the end surface of the first resin layer.
[17] The release film according to the above [16], wherein the second resin layer is provided on both side surfaces of the first resin layer, and each of the second resin layers has an overhanging portion.
[18] The release film according to the above [17], wherein the overhang length L1 of at least one of the overhanging portions of the second resin layer is 5 mm or more.
[19] Each of the overhanging portions of the second resin layer has a fixing portion fixed to each other.
The release film according to the above [17] or [18], which has a space between the fixing portion and the first resin layer.
[20] The release film according to any one of [16] to [19] above, wherein the planar shape is polygonal and a covering portion is provided on at least two or more sides thereof.
[21] The release film according to any one of [16] to [20] above, further comprising a third resin layer provided between the first resin layer and the second resin layer.
[22] A release having a folded portion, comprising a first resin layer and a second resin layer provided on at least one surface side of the first resin layer and having a composition different from that of the first resin layer. Mold film.
[23] The release film according to the above [22], wherein the end face of the first resin layer faces inward with respect to the outer edge of the release film.
[24] The release film according to the above [22] or [23], wherein the folded length L2 of the folded portion of the second resin layer is 5 mm or more.
[25] The release film according to any one of [22] to [24] above, wherein the planar shape is polygonal and covering portions are provided on at least two or more sides thereof.
[26] The release film according to any one of [22] to [25] above, further comprising a third resin layer provided between the first resin layer and the second resin layer.
[27] Production of a release film comprising a step of forming a covering portion covering at least a part of an end face of the first resin layer of a laminate including a first resin layer and a second resin layer. Method.
[28] A step of cutting the laminated body is provided.
The method for producing a release film according to the above [27], wherein at least a part of the end face of the first resin layer is covered with the second resin layer by the cutting to form the covering portion.
[29] The method for producing a release film according to the above [28], wherein the cutting is performed by at least one of push-cut cutting, shear cutting, and melt cutting.
[30] The method for producing a release film according to the above [27], wherein the covering portion is formed by using a covering member.
[31] The second resin layer is provided with an overhanging portion that projects outward from the end face of the first resin layer.
The method for producing a release film according to the above [27], wherein the overhanging portions are fixed to each other.
[32] The method for producing a release film according to the above [31], wherein the overhanging portions are fixed to each other by at least one of stable, an adhesive, fusion, and crimping.
[33] A method for producing a release film, comprising a step of folding back an end portion of a laminate including a first resin layer and a second resin layer inward to form a folded portion.
[34] The method for producing a release film according to the above [33], wherein the folded-back portion is fixed by at least one of stable, an adhesive, fusion, and crimping.
[35] A method for manufacturing a circuit board, wherein the circuit board is manufactured by using the release film according to any one of the above [1] to [26].
[36] A first resin layer and a second resin layer having a composition different from that of the first resin layer are prepared.
A laminating step of stacking a first resin film having a size smaller than that of the second resin film on the second resin film and further stacking a second resin film having a size larger than that of the first resin film. Have and
A method for manufacturing a circuit board, in which a press is performed after the laminating step.

According to the present invention, by making the end of the film a specific structure, it is possible to prevent the resin from seeping out from a specific resin layer such as an intermediate layer. It is also possible to provide a method for manufacturing a circuit board that does not cause contamination.

It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 1st Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on the modification of 1st Embodiment of this invention. It is a schematic diagram which shows the manufacturing method of the release film which concerns on 1st Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows the manufacturing method of the release film which concerns on 2nd Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 3rd Embodiment of this invention. It is a schematic diagram which shows the manufacturing method of the release film which concerns on 3rd Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 4th Embodiment of this invention. It is a schematic diagram which shows the manufacturing method of the release film which concerns on 4th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 5th Embodiment of this invention. It is a schematic diagram which shows the manufacturing method of the release film which concerns on 5th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on the modification of 5th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 6th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 7th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 8th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure which concerns on the modification of the release film which concerns on 8th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on 9th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on the modification of 1st Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on the modification of the 9th Embodiment of this invention. It is a schematic cross-sectional view which shows the edge structure of the release film which concerns on the modification of 1st Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 1 shows the end structure of the release film 10 according to the first embodiment of the present invention. As shown in FIG. 1, the release film 10 includes a first resin layer 11 and second resin layers 12 and 13 provided on both sides 11A and 11B of the first resin layer 11, respectively. The surfaces 11A and 11B form the main surface of the first resin layer 11. The release film 10 is a laminated body in which the second resin layer 12, the first resin layer 11, and the second resin layer 13 are integrated. The release film 10 is a multilayer film, and the second resin layer 12, the first resin layer 11, and the second resin layer 13 are arranged in this order.

In the release film 10, the first resin layer 11 is an intermediate layer arranged between the second resin layers 12 and 13, and may have cushioning properties. That is, the first resin layer 11 may have a flowable or flexible property at the temperature at which the press is performed. The second resin layers 12 and 13 are surface layers constituting the outermost surface of the release film 10. The second resin layers 12 and 13 are likely to have releasability, and as will be described later, for example, when the circuit board is manufactured, the second resin layers 12 and 13 have releasability with respect to the circuit board, the press plate, the cushion material and the like. good. That is, it is preferable that the material can be easily peeled off from the object to be pressed after pressing. The release film 10 includes the first resin layer 11 in addition to the second resin layers 12 and 13, so that the release film can be easily released from the press plate, the circuit board, and the like, and the unevenness followability to the circuit board can be improved. Will also be good.

The resin constituting the first resin layer 11 is not particularly limited, and examples thereof include polyolefin resins. Examples of the polyolefin resin include low-density polyethylene, linear low-density polyethylene, polyethylene such as ultra-high molecular weight polyethylene, homopolypropylene, polypropylene such as random polypropylene, ethylene-methylmethacrylate copolymer, and ethylene-ethylacrylate copolymer. Examples thereof include an ethylene-acrylic monomer copolymer such as an ethylene-acrylic acid copolymer and an ethylene-vinyl acetate copolymer. These may be used alone or in combination of two or more. Among these, low-density polyethylene, linear low-density polyethylene, ethylene-methylmethacrylate copolymer, and ethylene-vinyl acetate copolymer are preferable.

Further, the resin constituting the first layer 11 may be a polyolefin-based resin alone, but polystyrene, polyvinyl chloride, polyamide, polycarbonate, polysulphon, polyester and the like may be used as long as the object of the present invention is not impaired. A resin other than the polyolefin resin may be contained.
However, the first layer 11 is mainly composed of a polyolefin-based resin, and the polyolefin-based resin is, for example, 50% by mass or more, preferably 70% by mass, of the total amount of the resin component contained in the first layer 11. It is good to occupy% or more.

The second resin layers 12 and 13 have a composition different from that of the first resin layer 11, and for example, different types of resins may be used. Examples of the resin used for the second resin layers 12 and 13 include polyester-based resin, polyolefin-based resin, and polystyrene-based resin. These may be used alone or in combination of two or more. Of these, polyester-based resins are more preferable.
Therefore, it is more preferable that the resin used for the first resin layer 11 is a polyolefin-based resin and the resin used for the second resin layers 12 and 13 is a polyester-based resin.
Further, as the resin used for the second resin layers 12 and 13, the same kind of resin as the resin used for the first resin layer 11 may be used, for example, the first resin layer 11 and the resin. The resin used for the second resin layers 12 and 13 may be a polyolefin resin.
When the same type of resin is used, for example, at least one of the molecular weight, the type of the constituent monomers, and the molar ratio of the constituent monomers in the case of a copolymer may be different. Further, each of the first resin layer 11 and the second resin layers 12 and 13 may contain two or more kinds of resins, and the blending ratio of each resin may be appropriately different.

The polyester-based resin used for the second resin layer can be obtained, for example, by reacting a divalent acid as an acid component or an ester-forming derivative thereof with a diol component.
As the acid component, an aromatic dicarboxylic acid or an ester-forming derivative thereof is preferable, and as the polyester-based resin, a crystalline aromatic polyester-based resin using an aromatic dicarboxylic acid as an acid component and having crystallinity is preferable.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalindicarboxylic acid, and paraphenylenedicarboxylic acid. Examples of the ester-forming derivative of the aromatic dicarboxylic acid include the ester-forming derivative of the aromatic dicarboxylic acid, and specific examples thereof include dimethyl terephthalate, dimethyl isophthalate, dimethyl orthophthalate, and dimethyl naphthalindicarboxylic acid. , Dimethyl paraphenylenedicarboxylate and the like. These may be used alone or in combination of two or more.

As the diol component, a low molecular weight aliphatic diol may be used, or a low molecular weight aliphatic diol and a high molecular weight diol may be used in combination.
Examples of the low molecular weight aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, and 1,5-pentane. Examples thereof include diol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol. These may be used alone or in combination of two or more.
Examples of the high molecular weight diol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol and the like. These may be used alone or in combination of two or more.

Specific examples of the crystalline aromatic polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, butane diol polytetramethylene glycol copolymer, and butane terephthalate. Examples thereof include a diol-polycaprolactone copolymer. These may be used alone or in combination of two or more. Of these, polybutylene terephthalate is preferable because it is particularly excellent in non-staining property and crystallinity.
As the polyolefin resin used for the second resin layer, a resin containing poly (4-methyl-1-pentene) as a main component and a resin containing an alicyclic olefin resin as a main component shall be appropriately used. Can be done. As the polystyrene-based resin, a resin containing a polystyrene-based resin having a syndiotactic structure as a main component can be appropriately used.

The resin used for the second resin layers 12 and 13 may be composed of only the resin selected from the polyester-based resin, the polyolefin-based resin and the polystyrene-based resin described above, but the property as a release layer is impaired. Unless otherwise specified, in addition to the resin selected from the above-mentioned polyester-based resin, polyolefin-based resin, and polystyrene-based resin, a thermoplastic resin and a rubber component other than these may be contained.
Examples of the thermoplastic resin other than these include, but are not limited to, polyolefins, modified polyolefins, polystyrenes, polyvinyl chlorides, polyamides, polycarbonates, polysulfones, polyesters and the like. The rubber component is not particularly limited, and for example, natural rubber, styrene-butadiene copolymer, polybutadiene, polyisoprene, acrylic nitrile-butadiene copolymer, ethylene-propylene copolymer (EPM, EPDM), poly. Examples thereof include chloroprene, butyl rubber, acrylic rubber, silicon 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 resins and rubber components may be used alone or in combination of two or more.
However, the resin selected from the above-mentioned polyester-based resin, polyolefin-based resin, and polystyrene-based resin may be a main component in each of the second resin layers 12 and 13, for example, the resin component contained in the second resin layer. It is preferable to occupy 50% by mass or more, preferably 70% by mass or more of the whole.
The second resin layers 12 and 13 may have different compositions from each other, but may have the same composition. With the same composition, the release film 10 can be easily manufactured.

Further, additives may be appropriately added to the resins constituting the first resin layer 11 and the second 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 secure the cushioning property, the first resin layer 11 preferably has a lower elastic modulus in a high temperature environment than the second resin layers 12 and 13. Specifically, it is preferable that the storage elastic modulus of the first resin layer 11 is lower than that of the second resin layers 12 and 13, respectively. The storage elastic modulus is the storage elastic modulus at 180 ° C. measured under the following conditions by a dynamic viscoelasticity measuring device (for example, DVA-200 manufactured by IT Measurement Control Co., Ltd.).
Measurement mode Tensile temperature rise rate 5 ° C / min
Data acquisition interval 1 ° C / min
Measurement frequency 1Hz
Distortion 0.1%
Static / dynamic ratio 2
Minimum load 1cN
Specifically, the storage elastic modulus of the first resin layer 11 is preferably 1.0 × 10 ⁶ to 1.5 × 10 ⁷ Pa.
The storage elastic modulus of the second resin layers 12 and 13 is preferably, for example, larger than 1.5 × ^{107 Pa, preferably 1.5 × 10 7 to} 5.0 × 10 ⁸ Pa.

Further, it is preferable that the flow start temperature of the first resin layer 11 is lower than that of the second resin layers 12 and 13. The flow start temperature is, for example, when a sample of each layer (for example, 25 mm × 25 mm) is placed on a hot plate or the like and heated at about 10 ° C./min from room temperature, the sample area becomes 10 due to the flow. It means a temperature that becomes wider by% or more.
The flow start temperature of the first resin layer can be selected or adjusted according to the temperature of the hot press, for example, 80 to 200 ° C., but may be in the range of 80 to 120 ° C., or 120. It may be in the range of about 160 ° C. or may be in the range of 160 to 200 ° C. Similarly, the flow start temperature of the second resin layer can be selected or adjusted according to the temperature of the hot press, for example, 160 to 280 ° C., but may be in the range of 160 to 200 ° C. However, it may be in the range of 200 to 240 ° C. or in the range of 240 to 280 ° C.
The flow start temperature of the first resin layer is preferably 20 ° C. or higher lower than the temperature at which hot pressing is performed. It is more preferably 30 ° C. or higher, further preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher.
The flow start temperature of the second resin layer is preferably 20 ° C. or higher higher than the temperature at which hot pressing is performed. It is more preferably 30 ° C. or higher, further preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher.
Further, the difference between the flow start temperature of the first resin layer and the flow start temperature of the second resin layer is preferably 40 ° C. or higher. It is more preferably 60 ° C. or higher, still more preferably 80 ° C. or higher.

The thickness of the first resin layer 11 is preferably larger than the thickness of each of the second resin layers 12 and 13 from the viewpoint of ensuring appropriate cushioning property and unevenness followability. The thickness of the first 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 second resin layers 12 and 13 is preferably 1 to 100 μm, more preferably 5 to 50 μm, and even more preferably 10 to 20 μm. By setting the thickness to 1 μm or more, it is possible to prevent the release film from being torn during transportation or press molding. Further, by setting the thickness to 100 μm or less, it is possible to prevent the unevenness-following property from being deteriorated during press molding.
The thickness of each resin layer is an average thickness, and for example, it is preferable to adopt an average thickness measured at 10 points other than the end portion of the release film.

As shown in FIG. 1, in the present embodiment, one of the pair of second resin layers 12 and 13 resin layer 12 forms a covering portion 14 that covers the end face 11E. In the embodiment shown in FIG. 1, the second resin layer 12 covers the first resin layer 11 from one surface 11A to the end surface 11E. Since the release film 10 is provided with the covering portion 14, it is possible to prevent the resin constituting the first resin layer 11 from seeping out from the end face 11E even when heated and pressed during press working or the like. ..
In addition, in this specification, "covering" means that an end face or a surface is covered, and does not necessarily have to be in contact with a covering target. Further, it does not necessarily have to be in close contact with the object to be covered, and there may be a space between the covering portion and the end face or the surface.

As shown in FIG. 1, the second resin layer 12 covers the entire end surface 11E of the first resin layer 10 and is arranged on the other surface 11B of the first resin layer 11. It is preferable to connect to the resin layer 13 of 2. By connecting the pair of second resin layers 12 and 13 to each other in this way, it is possible to more effectively prevent the resin from seeping out from the end face.
However, as shown in FIG. 2, the second resin layer 12 does not need to cover the entire end face 11E in the cross section, and the second resin layers 12 and 13 do not have to be connected to each other.
Further, although the second resin layers 12 and 13 are in direct contact with each other in the configuration shown in FIG. 1, the second resin layers 12 and 13 do not necessarily have to be in direct contact with each other, and the second resin layers 12 and 13 are third resin layers and the like described later. It may be connected via a member other than the resin layer of 1.
In this embodiment, as will be described later, the end face 11E can be covered by plastically deforming the second resin layer 12 so as to extend it. Therefore, the thickness of the second resin layer 12 on the end surface 11E (that is, the thickness of the covering portion 14) is thinner than the average thickness of the above-mentioned second resin layer 12 on one surface 11A. May be good.

In the first embodiment, the end surface 11E of the end portion of the first resin layer 11 may be inclined with respect to one surface 11A as shown in FIG. When the end surface 11E is inclined with respect to one surface 11A, the thickness of the first resin layer 11 decreases toward the tip 11F. That is, the thickness of the end portion of the first resin layer 11 may be smaller than the average thickness of the first resin layer described above. In other words, the tip 11F of the first resin layer 11 may have a tapered shape. The end surface 11E may be an inclined surface that is inclined at an obtuse angle with respect to one surface 11A. The end face 11E does not have to be a flat surface, and may include a curved surface or the like as appropriate. Similarly, the covering portion 14 may have an inclined surface.

The release film according to the present embodiment may be in the form of a single leaf or may be wound in a roll shape. The single-wafer-shaped release film is used when pressing a sheet-shaped circuit board or the like by, for example, a batch press or a quick press as described later. The single-leaf mold release film has, for example, a polygonal shape (the plane shape is a polygon) in a plan view, and is typically a quadrangle such as a rectangle or a square, but may be circular. Further, it is preferable that each end portion of the release film constituting each side (that is, four sides in the case of a quadrangle) is formed by the end face 11E having the covering portion 14 as described above. Since the entire sheet-fed release film is generally pressed by a press plate that is one size larger than the release film, the first resin can be obtained by providing a covering portion 14 on each end portion constituting each side. The exudation of the layer 11 can be effectively prevented.

In the single-leaf mold release film, the entire end face of the first resin layer 11 does not necessarily have to be covered, and may be partially covered, but it is preferable that the first resin layer 11 is covered in a certain proportion or more. Specifically, when the outer edge of the release film is observed from the direction perpendicular to the thickness direction over the entire circumference, the area of the first resin layer covered with the covering portion is defined as "A1", and the first When the area of the exposed portion of the resin layer is "B1", the coating ratio calculated by the following formula may be, for example, 30% or more, preferably 50% or more, more preferably 70% or more. Most preferably 100%.
Coverage ratio = A1 / (A1 + B1) x 100

Similarly, in a single-wafer release film, not all of the edges constituting each side are necessarily composed of the end face 11E having the covering portion 14, and only the edges constituting some sides are covered. It may be composed of an end face 11E having a portion 14. When the planar shape of the release film is polygonal, it is preferable that the covering portion 14 is provided on at least two sides or more. For example, in a quadrangle, the ends constituting the sides facing each other may be formed by the end surface 11E having the covering portion 14. Even with such a configuration, for example, when the entire release film is not pressed, the exudation of the resin constituting the first resin layer 11 is effectively prevented.

On the other hand, in the roll-shaped release film, it is preferable that both end portions are composed of end faces 11E having a covering portion 14. The roll-shaped release film is pressed while being conveyed by, for example, roll-to-roll, but at that time, exudation occurs from both side ends. Therefore, exudation is performed by providing a covering portion 14 at both side ends. Can be effectively prevented.

Further, also in the roll-shaped release film, both side end portions do not necessarily have to be completely covered by the covering portion, and may be partially covered by the covering portion, but must be covered by a certain ratio or more. Is preferable. Specifically, when observing both end portions of the release film parallel to the TD direction, the area of the first resin layer covered with the covering portion is set to "A2", and the portion where the first resin layer is exposed. When the area of is "B2", the covering ratio calculated by the following formula may be, for example, 30% or more, preferably 50% or more, more preferably 70% or more, and most preferably 100%. ..
Coverage ratio = A2 / (A2 + B2) x 100

However, the roll-shaped release film may be cut out and used in the form of a single leaf. A covering portion may be provided as appropriate according to the above method.

Next, an example of the method for producing a release film according to the present embodiment will be described with reference to FIG. For the release film according to the present embodiment, first, a laminate 16 composed of a second resin layer 12, a first resin layer 11, and a second resin layer 13 is prepared. The method for producing the laminate 16 is not particularly limited, and for example, a water-cooled or air-cooled coextrusion inflation method, a coextrusion method such as a coextrusion T-die method, or a film for forming each resin layer is produced. Examples thereof include a method of laminating films by dry lamination and hot press molding, an extrusion lamination method, and a solvent casting method.

Next, the release film 10 is obtained by cutting the laminated body 16. At the time of the cutting, the second resin layer 12 is deformed to form the covering portion 14. Here, as shown in FIG. 3, the laminated body 16 in the present embodiment may be cut by push-cut cutting using the push-cut blade 17. Further, the push-cutting blade 17 may have an inclined surface 17A at the tip thereof, and for example, a Thomson blade may be used. Although the push-cutting blade 17 is provided with inclined surfaces 17A on both sides of the tip in FIG. 3, the inclined surface 17A may be provided on only one surface.
When the laminate 16 supported by, for example, the base 18 is pressed and cut from the surface on the second resin layer 12 side by the push cutting blade, the first resin layer 11 formed by cutting is formed as shown in FIG. The end surface 11E becomes an inclined surface along the shape of the inclined surface 17A, and the second resin layer 12 is extended to cover the end surface 11E of the first resin layer 11A, whereby the covering portion 14 is formed. Will be done. A roll-shaped release film can also be obtained by winding the laminated body after forming the covering portion 14.
According to the above method, since a release film having a covering portion at an end can be produced by a simple process, a release film with less exudation can be easily produced.

<Second embodiment>
FIG. 4 shows the edge structure of the release film according to the second embodiment. The difference between the second embodiment and the first embodiment is the structure of the end portion of the release film. Specifically, in the first embodiment, the end face is covered with one of the pair of second resin layers, but in the present embodiment, the end face is covered with both of the pair of second resin layers. Be covered. That is, a pair of second resin layers form a covering portion.
Hereinafter, the release film according to the second embodiment will be described as different from the first embodiment, and the description thereof will be omitted, which is the same as that of the first embodiment.

In the second embodiment, the release film 20 has a first resin layer 21 and second resin layers 22 and 23 provided on both sides 21A and 21B of the first resin layer 21, respectively. A covering portion 24 is provided on the end surface 21E of the resin layer 21 of the above. In the embodiment shown in FIG. 4, the end surface 21E has an inclined surface 21G and an inclined surface 21H. Here, in the present embodiment, the covering portion 24 is composed of both the second resin layers 22 and 23. That is, each of the second resin layers 22 and 23 covers the end face of the first resin layer 21. In the embodiment shown in FIG. 4, the second resin layer 22 covers the first resin layer 21 from one surface 21A to the end surface 21E. Similarly, the second resin layer 23 covers the first resin layer 21 from the other surface 21B to the end surface 21E. The first and second resin layers 22 and 23 are preferably connected on the end face 21E.
Also in this embodiment, the release film 20 is provided with the covering portion 24, so that the resin constituting the first resin layer 21 is immersed from the end face 21E even when heated and pressed during hot press working or the like. It can be prevented from squeezing out.

The pair of second resin layers 22 and 23 are arranged 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 by the covering portion 24 in the cross section.
Further, also in this embodiment, the end face 21E can be covered by plastically deforming the second resin layers 22 and 23 so as to extend them, as will be described later. Therefore, the thickness of each of the second resin layers 22 and 23 on the end surface 21E may be thinner than the average thickness of each of the second resin layers 22 and 23 on one surface 21A and the other surface 21B. ..

Also in the second embodiment, the end portion of the first resin layer 11 has a tapered shape, but the tip end 21F is arranged at a position between the double-sided surfaces 21A and 21B in the thickness direction of the release film 30. The tip 21F may be connected to each of the surfaces 21A and 21B at an obtuse angle via the inclined surfaces 21G and 21H constituting the end surface 21E. The inclined surfaces 21G and 21H do not have to be flat, and may include curved surfaces and the like as appropriate.

Next, an example of a method for producing a release film according to the present embodiment will be described. For the release film according to the present embodiment, first, a laminate 26 composed of a second resin layer 22, a first resin layer 21, and a second resin layer 23 is prepared. Next, the release film 20 is obtained by cutting the laminated body 26, and the above-mentioned covering portion 24 is formed by the second resin layers 22 and 23 by the cutting. Here, as shown in FIG. 5, the laminated body 20 in the present embodiment may be cut by push-cutting using a shear blade 27. The shear blade 27 is generally composed of an upper blade 27A and a lower blade 27B, and the upper blade 27A and the lower blade 27B are brought close to each other along the thickness direction and cut by applying a shearing force to the laminated body 26. It is something to do. By such cutting, the end face 21E of the first resin layer 21 has a tapered shape, and the second resin layers 22 and 23 are deformed so as to extend along the shape of the end face 21E, as shown in FIG. A covering portion 24 that covers the end face 21E is formed on the surface.

<Third embodiment>
When the end face of the first resin layer is covered with the pair of second resin layers as described above, the configuration is not limited to the configuration of the second embodiment described above, and may have various shapes, for example. , The release film 30 according to the third embodiment shown in FIG. 6 may have a configuration like that. It should be noted that the release film according to the third embodiment described below is the same as the second embodiment in that the differences from the second embodiment are explained and the description is omitted.

In the release film 30 according to the third embodiment, as shown in FIG. 6, the second resin layers 32 and 33 project outward from the end face 31E. That is, the second resin layers 32 and 33 have overhanging portions 32F and 33F, respectively. Since the second resin layer has an overhanging portion, the first resin layer 31 is less likely to seep out of the release film. It is preferable that the lengths of the overhanging portions 32F and 33F are larger than the average thickness of the second resin layers 32 and 33 having the overhanging portions 32F and 33F, respectively. Further, the overhanging portions 32F and 33F may be adhered to each other. Since the overhanging portion is adhered, it is possible to prevent exudation more effectively. Examples of the bonding method include heat welding, chemical welding, and bonding with an adhesive. In the form shown in FIG. 6, the end surface 31E has inclined surfaces 31G and 31H.

Also in the production of the release film 30 according to the present embodiment, first, the laminated body 36 composed of the second resin layer 32, the first resin layer 31, and the second resin layer 33 is prepared. Next, the release film 30 is obtained by cutting the laminated body 36, and the covering portion 34 is formed by the cutting. Here, as shown in FIG. 7, the laminated body 30 in the present embodiment may be cut by melt cutting using a heating blade 37. The second resin layers 32 and 33 can be stretched while being melted to cover the end face 31E and form the covering portion 34. Further, when melt-cut, the second resin layers 32 and 33 are fused to each other on the end face 31E. Further, since the end portion of the first resin layer 31 is melted and stretched, the shape of the tip thereof becomes more elongated. Since not only the first resin layer 31 but also the second resin layers 32 and 33 are cut while being melted, they are easily stretched, and the stretched second resin layers 32 and 33 cause the first resin layer 31. It becomes possible to cover the end face 31E of.
The heating blade 37 may be heated to a temperature at which at least the second resin layers 32 and 33 are melted. For example, the temperature is about 30 ° C. higher than the melting point of the resin used, preferably 5 to 20 ° C. higher. It should be heated.
The heating blade 37 is a push-cutting blade, and specifically, the mode of the push-cutting blade having an inclined surface 37A at the tip thereof is shown, but it may be other than the push-cutting blade.

In the first to third embodiments described above, a configuration is shown in which a covering portion is formed on the end face of the first resin layer by push cutting, shear cutting, and melt cutting, but other cutting methods are used. , A covering portion may be formed.
Further, in the shear cutting and melt cutting shown in the second and third embodiments, the covering portion was formed by a pair of second resin layers provided on both sides of the first resin layer. However, even when the covering portion is formed by these cutting methods, the type of resin constituting the second resin layer is appropriately selected, and the cutting conditions are appropriately selected, as in the first embodiment. , The covering portion may be formed only by one of the second resin layers.
Further, in the second and third embodiments, the second resin layers 22, 23 (or 32, 33) are connected to each other on the end face 21E (or 31E), but the first aspect is shown. Similar to the modification of the embodiment (see FIG. 2), it is not necessary to connect to each other, and the end face may have a portion not covered by the covering portion. Further, the second resin layers 22, 23 (or 32, 33) do not have to be in direct contact with each other, and are connected via a member other than the first resin layer, for example, a third resin layer described later. You may. Further, there may be a space between the covering portion and the end face.

Further, the end faces 11E, 21E, and 31E of the first to third embodiments do not necessarily have to have a tapered shape. For example, in the second embodiment, the two inclined surfaces 21G and 21H constituting the end surface 21E are both connected to one surface 21A and the other surface 21B at an acute angle, but these inclined surfaces 21G and 21H May be connected to one surface 21A and the other surface 21B at an acute angle. That is, the end surface 21E of the first resin layer 21 may have a shape that is recessed inward, and the covering portion 24 may also have a shape that is recessed inward accordingly. The end portion of such an embodiment can be formed, for example, by pressing a shear blade against the end face of the first resin layer at the time of cutting the release film.
Further, the shape in which the end face of the first resin layer is recessed can be applied even when the covering portion is formed only by one of the second resin layers 12 as in the first embodiment. Similarly, in that case, it can be formed by pressing the push-cutting blade against the end face of the first resin layer at the time of cutting the release film.

Further, although the end faces 11E, 21E, and 31E in the first to third embodiments have shown an aspect of having an inclined surface, it is not necessary to have an inclined surface, for example, by a vertical surface parallel to the thickness direction. It may be configured. Further, it may be a combination of a vertical surface and an inclined surface, or may have a shape other than these.

<Fourth Embodiment>
In the above-mentioned first to third embodiments, the covering portion is formed by cutting when the release film is produced, but the covering portion may be formed by a method other than cutting.
A specific example thereof will be described with reference to FIG. 8 as a fourth embodiment. Hereinafter, the release film according to the fourth embodiment will be described as different from the second embodiment, and the description thereof will be omitted, which is the same as that of the second embodiment.

Also in this embodiment, the release film 40 includes a first resin layer 41 and second resin layers 42 and 43 provided on both sides 41A and 41B of the first resin layer 41, respectively. In the present embodiment, as in the third embodiment, the second resin layers 42 and 43 have overhanging portions 42F and 43F, respectively. The release film 40 has a crimping portion 48 in which the overhanging portions 42F and 43F are pressed against each other and adhered to each other. The thickness of the crimping portion 48 is smaller (thinner) than the sum of the average thicknesses of the second resin layers 42 and 43 because it becomes thinner due to compression deformation.

Also in this embodiment, the release film 40 is provided with the covering portion 44, so that the resin constituting the first resin layer 41 permeates from the end face 41E even when heated and pressed during hot press working or the like. It can be prevented from being put out. Further, since the second resin layers 42 and 43 are adhered to each other, it is possible to more reliably prevent seepage.

Next, an example of the method for manufacturing the release film 40 of the present embodiment will be described with reference to FIG. In the present embodiment, as shown in FIG. 9, the second resin layer 43, the first resin layer 41, and the second resin layer 42 are laminated in this order in the same manner as in each of the above embodiments. Prepare 46. At this time, in the laminated body 46, the first resin layer 41 is intermittently provided, and a region 46A in which the first resin layer 41 is not provided is provided between the second resin layers 42 and 43. That is, in the laminated body 46, it is preferable that the plurality of first resin layers 41 are arranged along the plane direction.
Next, in the region 46A where the first resin layer 41 is not provided, the first and second resin layers 42, 43 are pressed so as to be in contact with each other, and the crimping portion 48 is crimped by heating or the like. Will be formed, thereby forming the covering portion 44 as well. Further, by the above steps, the overhanging portions 42F and 43F are provided, and the overhanging portions 42F and 43F are fixed to each other.
After that, the laminated body 46 may be cut along the crimping portion 48 or the like, if necessary, to obtain a plurality of release films 40. In FIG. 9, the cutting line is shown by a dotted line.

<Fifth Embodiment>
In the above-mentioned fourth embodiment, the first resin layer is not provided in the crimping portion, but the first resin layer may be provided in the crimping portion. A specific example thereof will be described with reference to FIG. 10 as a fifth embodiment. In the following description, the release film according to the fifth embodiment will be described as different from the fourth embodiment, and the description will be omitted, which is the same as that of the fourth embodiment.

Also in this embodiment, the release film 50 includes a first resin layer 51 and second resin layers 52 and 53 provided on both sides 51A and 51B of the first resin layer 51, respectively. In the present embodiment, the first resin layer 51 has an overhanging portion 51F like the second resin layers 52 and 53. The overhanging portions 51F, 52F, and 53F have a crimping portion 58 that is pressed against each other and adhered to each other. The crimping portion 58 forms a part of the covering portion 54. Since the thickness of the crimping portion 58 becomes thinner due to compression deformation, it is thinner than the total thickness of the second resin layers 52, 53 and the first resin layer 51.

With the above configuration, the end face 51E of the first resin layer 51 is covered with the covering portion 54. Therefore, also in this embodiment, it is possible to prevent the resin constituting the first resin layer 51 from seeping out from the end surface 51E of the first resin layer 51.

Next, an example of the method for manufacturing the release film 50 of the present embodiment will be described with reference to FIG. In the present embodiment, as shown in FIG. 11, the second resin layer 53, the first resin layer 51, and the second resin layer 52 are laminated in this order in the same manner as in the first embodiment described above. The laminated body 56 is prepared. Next, the laminated body 56 is partially compressed and deformed by a crimping means 57 such as a heated emboss roller, and the first resin layer 51 and the second resin layers 52 and 53 are partially crimped and crimped. The portion 58 is formed. After that, the laminated body 56 may be cut along the crimping portion 58 or the like to obtain a release film 50. The cutting line for manufacturing the release film shown in FIG. 10 is shown by a dotted line. The cutting position when manufacturing the release film 50 does not have to be on the crimping portion 58, and may be the position shown by the alternate long and short dash line in FIG. A cross-sectional view of the release film 50 obtained in such a case is shown in FIG.
Even in such an embodiment, the exudation of the first resin layer 51 can be suppressed. Further, in the manufacturing method, it is not necessary to match the cutting position with the crimping portion 58, so that the manufacturing becomes easier. For example, when embossing and crimping while transporting the laminated body 56 by roll-to-roll, it is possible to perform cutting in parallel with the embossing.

In the fourth and fifth embodiments described above (see FIGS. 8 to 12), the end faces 41E and 51E of the first resin layers 41 and 51 are deformed during, for example, crimping, and the inclined surfaces 41G and 41H are formed. , 51G, 51H are preferable.
However, the end faces 41E and 51E do not necessarily have the inclined faces 41G, 41H, 51G and 51H, and may be formed of, for example, vertical planes (planes parallel to the thickness direction). In the case of being formed by a vertical surface, there may be a space between the covering portion formed by crimping the second resin layer and the end surface. However, even if there is space, the exudation of the resin constituting the first resin layer can be appropriately prevented.

Further, in the above-mentioned fourth embodiment (see FIG. 9), the second and third resin layers 42 and 43 are bonded to each other by crimping, but may be configured by an embodiment other than crimping and bonded by fusion. It may be adhered, or it may be adhered using an adhesive or the like.
Similarly, in the above-mentioned fifth embodiment (see FIG. 11), the first resin layer 51 and the second and third resin layers 52 and 53 are bonded to each other by crimping, but by an embodiment other than crimping. It may be bonded, for example, it may be bonded by fusion.

<Sixth Embodiment>
In the above-mentioned first to fifth embodiments, the covering portion covering the end face of the first resin layer is formed by the second resin layer, but the covering portion is made of another member other than the second resin layer. It may be formed by a certain covering member. Such a configuration will be described below as the release films 60 and 70 according to the sixth and seventh embodiments.
In the following, first, the difference between the release film according to the sixth embodiment and the first embodiment will be described with reference to FIG. 13, but the first point is that the description is omitted. It is the same as the embodiment.
Further, the "separate member" means that when the laminate constituting the release film is composed of the first and second resin layers, it is a member different from the second resin layer. However, when other resin layers other than the first and second resin layers constituting the laminated body are provided, such as the third resin layer described later, the members are different from the other resin layers. However, the member different from the other resin layer such as the third resin layer may have the same resin composition as the other resin layer.

Also in the sixth embodiment, the release film 60 includes a first resin layer 61 and second resin layers 62 and 63 provided on both sides 61A and 61B of the first resin layer 61, respectively. In the present embodiment, the covering portion 64 that covers the end face 61E of the first resin layer 61 is formed by a covering member. As the covering member, for example, a resin film can be used. The covering portion 64 may have any structure as long as it covers the end face 61E. For example, the covering portion 64 may be entirely covered from the outer surface of the second resin layer 62 to the end face of the first resin layer and the outer surface of the second resin layer 63. good. The covering portion 64 may be adhered to the outer surfaces of the second resin layers 62 and 63 with an adhesive, or may be adhered by fusing, crimping, or the like. The covering portion 64 may be formed by using a plurality of covering members.
Also in the sixth embodiment, when the release film 60 includes the covering portion 64, it is possible to effectively prevent the resin constituting the first resin layer 61 from seeping out.

As the resin film constituting the covering portion 64, a known resin film may be used, but a resin film having a higher flow start temperature than the first resin layer 61 and a higher storage elastic modulus may be used.
As the resin constituting the resin film, specifically, the resin shown as the resin that can be used for the second resin layer as described above may be appropriately selected and used. For example, a polyester resin, a polyolefin resin, etc. A polystyrene-based resin or the like may be used, or a thermoplastic resin or a rubber component may be appropriately added to these resins for use. The detailed description of these resins is as described in the second resin layer.
The thickness of the resin film is not particularly limited, but is, for example, 1 to 250 μm, preferably 5 to 150 μm.

When producing the release film 60 according to the present embodiment, first, a laminate provided with the first resin layer 61 and the second resin layers 62 and 63 is prepared in the same manner as in each of the above embodiments. In addition, a covering member (for example, a resin film) is prepared. Then, the release film 60 can be obtained by attaching the covering member (resin film) to the end portion of the laminated body.

<7th Embodiment>
Next, the release film 70 according to the seventh embodiment of the present invention will be described.
FIG. 14 shows the end structure of the release film 70 according to the seventh embodiment. Also in this embodiment, the release film 70 includes a first resin layer 71 and second resin layers 72 and 73 provided on both sides 71A and 71B of the first resin layer 71, respectively. In the present embodiment, the covering portion 74 that covers the end surface 71E of the first resin layer 71 is formed by a covering member, and here, the covering member is a sealing material. By providing the coating portion 74 formed by the coating member (sealing agent), the release film 70 can effectively prevent the resin constituting the first resin layer 71 from seeping out.

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 second resin layers 72 and 73 in addition to the first resin layer 71. .. By laminating the encapsulant layer on the end faces 72E and 73 of the second resin layers 72 and 73, it is more reliable to prevent the resin constituting the first resin layer 71 from seeping out from the end faces 71E. can do.

For the release film 70, as in each of the above embodiments, first, a laminate having a first resin layer 71 and second resin layers 72, 73 is prepared, and then sealed at the end of the laminate. It can be manufactured by applying an agent to form a covering portion 75.

The encapsulant constituting the covering portion 74 is not particularly limited, but an epoxy resin, a urethane resin, a silicone resin, a phenol resin, a polyimide resin, or the like may be used. The thickness of the covering portion 74 is, for example, 1 to 1000 μm, preferably 10 to 500 μm.

The covering portion made of the covering member, which has been exemplified and described in the sixth and seventh embodiments, is not limited to the resin film and the encapsulant as long as it can cover the end face of the first resin layer. .. Further, in the sixth and seventh embodiments, the covering portion covers not only the end face of the first resin layer but also the end face of the second resin layer, but the end face of the first resin layer is covered. It is not necessary to cover the end face of the second resin layer as long as it covers. For example, the covering portion 74 formed by the encapsulant layer shown in the seventh embodiment may cover only the end face of the first resin layer.

<Eighth Embodiment>
In the above-mentioned first to seventh embodiments, the end face of the first resin layer is covered with the covering portion, but the end face of the first resin layer needs to be covered with the covering portion. However, the release film according to the eighth embodiment has a configuration in which the end portion of the second resin layer is arranged so as to project outward from the end face of the first resin layer.
Hereinafter, the difference between the release film 80 according to the eighth embodiment and the first embodiment will be described with reference to FIG. 15. The point that the description is omitted is the same as that of the first embodiment.

The release film 80 according to the eighth embodiment includes a first resin layer 81 and second resin layers 82 and 83 provided on both sides 81A and 81B of the first resin layer 81, respectively. In the present embodiment, both ends of the second resin layers 82 and 83 are arranged so as to project outward from the end face 81E of the first resin layer 81, forming the overhanging portions 82E and 83E.
According to such an aspect, when the release film 80 is used in a hot press, even if the resin constituting the first resin layer 81 flows by the hot press, the flowed resin is still in the overhanging portion 82E. By staying between, and 83E, it is possible to prevent the release film 80 from seeping out from the outer edge.

Here, the overhang length L1 of the second resin layers 82 and 83 stays between the overhang portions 82E and 83E even if the resin of the first resin layer 81 flows by the hot press, and the release film 80 It suffices to have a length that appropriately prevents it from seeping out from the outer edge. The overhang length L1 is not particularly limited, but is, for example, 5 to 50 mm, preferably 10 to 30 mm. The overhang length of the second resin layer 82 and the overhang length of the second resin layer 83 may be different.

As the release film 80 according to the present embodiment, a resin film for forming the first resin layer 81 and second and third resin films for forming the second resin layers 82 and 83 are prepared. , These can be manufactured by adhering and laminating them by heat crimping or the like. At this time, as the second and third resin films, ones that are one size larger than the first resin film may be prepared. Since the release film of the present embodiment can be manufactured only by heat-pressing the resin film as described above, the manufacturing method thereof becomes easy.

When the release film 80 in the present embodiment is, for example, a sheet-fed shape, it is typically a quadrangle such as a rectangle or a square, but each end of the release film constituting each side (that is, four sides) is formed. It is preferable that the overhanging portions 82E and 83E are provided as described above. However, as in the case of the covering portion shown in the first to seventh embodiments, it is not always necessary to provide the overhanging portion on all the end portions constituting each side of the release film 80. When the planar shape of the release film is polygonal, it is preferable that the overhanging portion is provided on at least two or more sides.
Further, when the release film 80 is in the form of a roll, it is preferable that the overhanging portions 82E and 83E are provided at both end portions in the same manner as the above-mentioned covering portion.

The overhanging portions 82E and 83E at each end of the release film 80 according to the present embodiment may be fixed to each other by fixing means (not shown) such as a stable, an adhesive, fusion, and crimping. When the overhanging portions 82E and 83E are fixed to each other, the first resin layer 81 is sandwiched by the second resin layers 82 and 83 from above and below, and the laminated structure becomes more stable.
Further, it is preferable that the overhanging portions 82E and 83E are fixed to each other so that the overhanging portions 82E and 83E form a covering portion 84 that covers the end face 81E. At this time, as shown in FIG. 16, at least a part of the covering portion 84 may be arranged with respect to the end face 81E via the space 88, but the space 88 may not be provided. In this case, the release film 80 has a space between the fixing portion in which the overhanging portions 82E and 83E of the second resin layer are fixed to each other and the first resin layer 81.

Further, for fixing by the fixing means, for example, in a single-wafer-shaped release film such as a quadrangle, each end constituting each side (four sides in the case of a quadrangle) may be fixed by the fixing means, but not all sides are necessarily fixed. It is not necessary to fix each end constituting the. Even if the ends constituting all the sides are not fixed, for example, by fixing the ends constituting the two sides facing each other by the fixing means, the first resin layer 81 can be seconded by the fixing. It will be properly sandwiched by the resin layers 82 and 83 of the above.

Further, when the first resin layer 81 is sandwiched by the second resin layers 82 and 83 due to the fixing of the fixing means as described above, the first resin layer 81 is attached to both sides 81A and 81B, respectively. Therefore, it is not necessary to bond the second resin layers 82 and 83, respectively. Therefore, in the production of the release film 80, it is not necessary to bond the resin films to each other by pressure bonding or the like. That is, the release film 80 can be manufactured by stacking the three resin films and fixing the overhanging portion by the fixing means, which simplifies the manufacturing method and does not require the introduction of large-scale manufacturing equipment. It will be easy to manufacture.
Further, in the present embodiment, both ends of the second resin layers 82 and 83 are arranged so as to project outward from the end face 81E of the first resin layer 81 to form the overhanging portions 82E and 83E. The lengths of the overhangs do not have to be the same. That is, the overhanging portion 82E may be longer than the overhanging portion 83E, or the overhanging portion 82E may be shorter than the overhanging portion 83E.

<9th embodiment>
FIG. 17 shows the edge structure of the release film according to the ninth embodiment. Hereinafter, the release film 90 according to the ninth embodiment will be described as different from the first embodiment, and the description thereof will be omitted, which is the same as that of the first embodiment.
The release film 90 according to the ninth embodiment includes a first resin layer 91 and second resin layers 92 and 93 provided on both sides 91A and 91B of the first resin layer 91, respectively. In the present embodiment, the release film 90 has a folded-back portion 98. That is, it has a structure in which the end portion is folded back toward the inside of the release film. Therefore, the end surface 91E of the first resin layer 91 is located inside the outer edge 90E of the release film 90. Further, the end surface 91E of the first resin layer 91 faces inward with respect to the outer edge 90E of the release film 90. Then, in the folded-back portion 98, one second resin layer 92 is arranged on the outer peripheral side, and the other second resin layer 93 is arranged on the inner peripheral side. According to such an embodiment, even if the resin constituting the first resin layer 91 flows by hot pressing, the resin does not immediately flow out to the outside of the outer edge 90E of the release film 90, so that the release film 90 does not flow immediately. It is possible to prevent the resin from seeping out from the outer edge of the mold.

As shown in FIG. 17, in the release film 90, the outer surfaces of the second resin layer 93 come into contact with each other at the folded-back portion 98, but these are bonded by an adhesive, fused, crimped, stable, or the like. It may be fixed by fixing means. By fixing the outer surfaces of the second resin layer 93 to each other, the release film 90 can be easily held in a state where the end portion is folded back.
The release film 90 may be formed, for example, by folding back the ends of the laminate composed of the first resin layer 91 and the second resin layers 92 and 93. In the present embodiment, the folded portion has a gently curved surface shape, but it may be crushed. The thickness of the folded portion may be smaller than the average thickness of the release film.

In the present embodiment, the folded length L2 (that is, the length from the outer edge 90E of the release film 90 to the end face 91E of the first resin layer 91) is a resin constituting the first resin layer 91 by hot pressing. Even if it flows out from the end surface 91E of the resin layer 91, it may have a length that stays inside the outer edge 90E of the release film 90. The length L2 is not particularly limited, but is, for example, 1 to 50 mm, preferably 5 to 30 mm.

Further, when the release film 90 in the present embodiment is, for example, a sheet-fed shape, it is typically a quadrangle such as a rectangle or a square, but the edge of the release film constituting each side (that is, four sides). Each portion may have a folded portion. However, it is not always necessary that all the edges constituting each side of the release film 90 have a folded portion. For example, when the planar shape of the release film is polygonal, it is preferable to have folded portions on at least two or more sides. Further, when the release film 90 is in the form of a roll, it is preferable that both end portions have folded portions, as in the case of the covering portion described above.

<Other variants>
In the release film according to the above-mentioned first to ninth embodiments, the second resin layer is provided on both sides of the first resin layer, but the second resin layer is provided only on one surface of the first resin layer. A resin layer may be provided. A specific example thereof is shown in FIG. FIG. 18 is a modification of the first embodiment, and the release film 10 is a second resin layer provided only on one surface 11A of the first resin layer 11 and the first resin layer 11. 12 is provided. In this modification, the covering portion 14 is formed by the second resin layer 12 as in the first embodiment. The structure of the covering portion 14 is as described in the first embodiment, but the second resin layer 13 is not provided on the other surface 11B. Therefore, the covering portion 14 formed by the second resin layer 12 does not come into contact with the resin layer (second resin layer) provided on the other surface 11B.

Similarly, in the second to third embodiments, the second resin layer may be provided only on one surface of the first resin layer, in which case the covering portion is the one second resin layer. It may be formed only by. Similarly, in the sixth to ninth embodiments, one of the pair of second resin layers may be omitted.
FIG. 19 shows a modified example of the ninth embodiment in which the second resin layer is provided only on one surface of the first resin layer. In this modification, the second resin layer 92 is arranged on the outer peripheral side in the folded portion. In the release film 90 (see FIG. 17) according to the ninth embodiment, the outer surfaces of the second resin layers are in contact with each other, but in this modification (see FIG. 19), the first resin layer 91 is in contact with each other. The other surfaces 91B may be in contact with each other, and the other surfaces 91B may be fixed by fixing means such as adhesion, fusion, crimping, and stable with an adhesive.
In the first to third embodiments and the sixth to ninth embodiments, the method for producing the release film in the case where the second resin layer 13 is provided only on one surface is a laminated body to be prepared. As described in each embodiment, except that one of the second resin layers is omitted in the above.

Further, in each embodiment, a third resin layer may be provided between the first resin layer and the second resin layer. The third resin layer preferably has a function as an adhesive layer for adhering the first resin layer and the second resin layer. As an example of the structure provided with the third resin layers 19A and 19B, FIG. 20 shows a modified example of the first embodiment. Note that FIG. 20 shows an embodiment in which one second resin layer 12 is connected to the other second resin layer 13 via the third resin layer 19B, but a third resin layer is provided. In this case, the second resin layers 12 and 13 may be in direct contact with each other. Of course, the second resin layers 12 and 13 may not be connected to each other, and a part of the end face 11E may not be covered by the covering portion 14.
In the first to sixth embodiments, the third resin layer may or may not form a covering portion together with the second resin layer as shown in FIG. 20. ..

As the resin constituting the third resin layer, any resin may be used as long as it fulfills its function. For example, the resin constituting the main component of the first resin layer and the resin in contact with the third resin layer are in contact with each other. It is preferable to contain the resin constituting the main component of the resin layer of 2. Therefore, it is preferable that the third resin layer contains a polyolefin resin other than the polymethylpentene resin and at least one selected from the polyester resin and the polymethylpentene resin. Further, the third resin layer may contain a thermoplastic resin and a rubber component other than these. Details of these resins, thermoplastic resins, and rubber components are as described in the first and second resin layers.
The thickness of each of the third resin layers is, for example, 5 to 50 μm, preferably 10 to 30 μm.

Here, when the second resin layer is provided on both surfaces of the first resin layer, the third resin layer is provided only between the first resin layer and one of the second resin layers. However, as shown in FIG. 20, it is preferable that the resin layer is provided between the first resin layer and both of the second resin layers. As described above, the release film can be bonded to the first resin layer with a high adhesive force by providing the third resin layer.

By providing each of the above forms, the release film of the present invention is such that the resin constituting the first resin layer does not easily seep out to the outside of the release film by the heating press. Specifically, the release film of the present invention preferably has a first resin layer exudation amount of 1.5 mm or less when pressed at 170 ° C. for 30 minutes at a pressure of 30 kgf / cm ² . It is more preferably 1.3 mm or less. By setting the exudation amount to the above upper limit value or less, it is possible to effectively prevent contamination of, for example, a circuit board, a press plate, and an auxiliary material such as a cushion material.
The exudation amount is the exudation length of the resin constituting the first resin layer with reference to the outer edge of the release film when heat-pressed under the above-mentioned pressing conditions, and is the maximum exuding length. Adopt the value.

<How to use the release film>
The release film of the present invention can be suitably used, for example, when manufacturing a circuit board such as an FPC. The circuit board can be manufactured by preparing a core substrate, a coverlay film, and a release film, and integrating the core substrate and the coverlay film by hot pressing using the release film. Hereinafter, a method for manufacturing a circuit board will be described in detail.

The core substrate includes a base material made of a polyimide resin, a polyester resin, a 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 sides.
The coverlay film includes a base film and an adhesive layer provided on one surface of the base film. Examples of the base film include a polyimide resin film, a polyester resin film, and a liquid crystal polymer. The adhesive layer is composed of an epoxy-based adhesive, an acrylic-based adhesive, or the like.
As the release film, the release film of the present invention described above can be appropriately selected and used. As will be described later, a pair of release films are prepared, but they may have the same configuration or different configurations. Further, as the release film, only one of the release films of the present invention described above may be used, but it is preferable to use the release film of the present invention described above for both release films.

In this manufacturing method, it is preferable to superimpose the above-mentioned core substrate, the coverlay film, and the release film. At this time, the coverlay film may be laminated on the core substrate so that the surface on the side where the adhesive layer is provided faces the core substrate side. Further, the coverlay film may be laminated on the surface provided with the circuit portion of the core substrate. Therefore, when the circuit portion is provided on both sides of the substrate, the coverlay film may be laminated on both sides of the substrate. Often, when the circuit portion is provided on one side of the substrate, it is advisable to superimpose the coverlay film on one side of the substrate.
Further, the release film may be laminated on both sides of the core substrate, and when the coverlay film is laminated on the core substrate, it may be laminated on the outside of the coverlay film.
Therefore, specifically, it is preferable to stack the release film / coverlay film / core substrate / release film or the release film / coverlay film / core substrate / coverlay film / release film in this order.

Next, as described above, the laminated core substrate, the coverlay film, and the release film are heat-pressed using a press plate to cover one or both sides of the core substrate. Are bonded and integrated by an adhesive layer, whereby a circuit board is obtained. The release film may be peeled off from the obtained circuit board.
In addition, for example, a pair of press plates may be provided and heat-pressed so as to sandwich the laminate, but a cushioning material or the like may be appropriately provided between the release film and the press plate. Examples of the cushioning material include glass cloth, papers, PVC films, polyester films, polyolefin films and the like.

In the release film of the present invention, the resin constituting the first resin layer does not easily seep out to the outside of the release film even when heated and pressed by the heating press as described above. Therefore, in the heating press, it is possible to prevent contamination of the circuit portion, the cushion material, the press plate, and the like caused by the release film.

As described above, in the release film, the second resin layer may be provided only on one surface. In such a case, the surface on the side where the second resin layer is provided may be directed to either the core substrate side or the press plate side, but it should be directed to the core substrate side in order to prevent contamination of the circuit board. Is preferable.

The circuit board described above may be manufactured by batch press, quick press, or roll-to-roll. When a batch press or a quick press is used, the core substrate, the coverlay film, and the release film may all be prepared in the form of a single sheet, and these may be overlapped and pressed to manufacture a circuit board.
In the case of roll-to-roll, the core substrate, the coverlay film, and the release film, which were wound in a roll shape, were unwound into a sheet shape and then stacked, and a press plate was used between the rolls. A circuit board may be manufactured by integrating the core substrate and the coverlay film by hot pressing. Further, the release film may be peeled off while transporting the circuit board between the rolls after obtaining the circuit board.

As a modification of the eighth embodiment, an example of a method for manufacturing a circuit board is shown. In the eighth embodiment, the release film is an integrated film including a first resin layer and second resin layers 82 and 83 provided on both sides of the first resin layer, respectively. On the other hand, each of these resin layers is not integrated, but is prepared as a separate resin film, and when pressed, a second resin layer (one second resin film) and a first resin layer (first resin layer) are used. The resin film) and the second resin layer (the other second resin film) can be laminated in this order. At this time, the size of the second resin film is made larger than that of the first resin film, and the overhanging portion is provided on the second resin film, so that the resin constituting the first resin film exudes to the outside. It is possible to prevent the surroundings from being polluted. That is, in the method of manufacturing a circuit board shown here, a first resin film having a size smaller than that of the second resin film is layered on the second resin film, and the size is larger than that of the first resin film. It has a laminating step of laminating a large second resin film. A circuit board can be manufactured by performing a press after such a laminating step. Each resin film used in the method for manufacturing a circuit board shown here can have the same configuration as each resin layer included in the release film according to the eighth embodiment.

The method of using the release film described above is an example, and the release film may be used in other embodiments. For example, a material other than a circuit board is manufactured by a heating press using a press plate. It may be used as a release film at the time of.

10, 20, 30, 40, 50, 60, 70, 80, 90 Release film 11, 21, 31, 41, 51, 61, 71, 81, 91 First resin layer 11E, 21E, 31E, 41E, 51E, 61E, 71E, 81E, 91E End faces of the first resin layer 12, 13, 22, 23, 32, 33, 42, 43, 52, 53, 62, 63, 72, 73, 82, 83, 92, 93 Second resin layer 14, 24, 34, 44, 54, 64, 74 Coating part 16, 26, 36, 46, 56 Laminated body 17 Push cutting blade 27 Shear blade 37 Heating blade 48, 58 Crimping part 57 Crimping means 82E , 83E Overhanging part

Claims (36)

A first resin layer and a second resin layer provided on at least one surface side of the first resin layer and having a composition different from that of the first resin layer are provided.
A release film having a covering portion that covers the end face of the first resin layer. The release film according to claim 1, wherein the second resin layer forms the covering portion. The second resin layer is provided on both sides of the first resin layer.
The release film according to claim 2, wherein each of the second resin layers forms the covering portion. The second or third aspect of the present invention, wherein the second resin layer provided on one surface and forming a covering portion is connected to the second resin layer on the other surface side of the first resin layer. Release film. The second resin layer is provided on both sides of the first resin layer.
The release film according to any one of claims 2 to 4, wherein each of the second resin layers has an overhanging portion that projects outward from the end face of the first resin layer. The release film according to claim 5, wherein the length of the overhanging portion is larger than the average thickness of the second resin layer having the overhanging portion. The release film according to claim 5 or 6, wherein the overhanging portions are adhered to each other. The release film according to claim 7, wherein the overhanging portions have a crimping portion that is pressed against each other and adhered to each other. The release film according to claim 8, wherein the thickness of the crimping portion is smaller than the sum of the average thicknesses of the respective second resin layers. The release film according to claim 1, wherein the covering portion is formed of a covering member. The release film according to claim 10, wherein the covering member is a resin film. The release film according to claim 10, wherein the covering member is a sealing agent. The release film according to any one of claims 1 to 12, wherein the planar shape is a polygon and a covering portion is provided on at least two or more sides thereof. The release film according to any one of claims 1 to 13, wherein the covering portion has an inclined surface. The release film according to any one of claims 1 to 14, further comprising a third resin layer provided between the first resin layer and the second resin layer. A first resin layer and a second resin layer provided on at least one surface side of the first resin layer and having a composition different from that of the first resin layer are provided.
A release film having a projecting portion in which the second resin layer projects outward from the end surface of the first resin layer. The release film according to claim 16, wherein the second resin layer is provided on both side surfaces of the first resin layer, and each of the second resin layers has an overhanging portion. The release film according to claim 17, wherein the overhang length L1 of at least one of the overhanging portions of the second resin layer is 5 mm or more. Each of the overhanging portions of the second resin layer has a fixing portion fixed to each other.
The release film according to claim 17 or 18, which has a space between the fixing portion and the first resin layer. The release film according to any one of claims 16 to 19, wherein the planar shape is a polygon and a covering portion is provided on at least two or more sides thereof. The release film according to any one of claims 16 to 20, further comprising a third resin layer provided between the first resin layer and the second resin layer. A release film comprising a first resin layer and a second resin layer provided on at least one surface side of the first resin layer and having a composition different from that of the first resin layer, and having a folded portion. 22. The release film according to claim 22, wherein the end face of the first resin layer faces inward with respect to the outer edge of the release film. The release film according to claim 22 or 23, wherein the folded length L2 of the folded portion of the second resin layer is 5 mm or more. The release film according to any one of claims 22 to 24, wherein the planar shape is a polygon and a covering portion is provided on at least two or more sides thereof. The release film according to any one of claims 22 to 25, further comprising a third resin layer provided between the first resin layer and the second resin layer. A method for producing a release film, comprising a step of forming a covering portion that covers at least a part of an end face of the first resin layer of a laminate including a first resin layer and a second resin layer. A step of cutting the laminate is provided.
The method for producing a release film according to claim 27, wherein at least a part of the end face of the first resin layer is covered with the second resin layer by the cutting to form the covering portion. The method for producing a release film according to claim 28, wherein the cutting is performed by at least one of push-cut cutting, shear cutting, and melt-cutting. The method for producing a release film according to claim 27, wherein the covering portion is formed by using a covering member. The second resin layer is provided with an overhanging portion that projects outward from the end face of the first resin layer.
The method for manufacturing a release film according to claim 27, wherein the overhanging portions are fixed to each other. The method for producing a release film according to claim 31, wherein the overhanging portions are fixed to each other by at least one of stable, an adhesive, fusion, and crimping. A method for producing a release film, comprising a step of folding back an end portion of a laminate including a first resin layer and a second resin layer inward to form a folded portion. The method for producing a release film according to claim 33, wherein the folded-back portion is fixed by at least one of stable, an adhesive, fusion, and crimping. A method for manufacturing a circuit board, wherein the circuit board is manufactured by using the release film according to any one of claims 1 to 26. A first resin layer and a second resin layer having a composition different from that of the first resin layer are prepared.
A laminating step of stacking a first resin film having a size smaller than that of the second resin film on the second resin film and further stacking a second resin film having a size larger than that of the first resin film. Have and
A method for manufacturing a circuit board, in which a press is performed after the laminating step.

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