CN113557136A

CN113557136A - Release film for printed wiring board production process, method for producing printed board, apparatus for producing printed board, and printed board

Info

Publication number: CN113557136A
Application number: CN202080020006.9A
Authority: CN
Inventors: 工藤俊介
Original assignee: Mitsui Chemicals Tohcello Inc
Current assignee: Mitsui Chemicals Tohcello Inc
Priority date: 2019-03-28
Filing date: 2020-03-24
Publication date: 2021-10-26
Anticipated expiration: 2040-03-24
Also published as: KR102601956B1; CN113557136B; WO2020196497A1; TW202043025A; KR20210121205A

Abstract

The present invention provides a release film for a printed wiring board manufacturing process, which has a high degree of followability, wrinkle resistance and release property, and a method for manufacturing a printed wiring board, which has a high degree of releasability, an adhesive agent outflow prevention property and a release film wrinkle generation prevention property. The above-mentioned technical problem is solved by the release film for printed circuit board manufacturing process and the method for manufacturing printed circuit board using the release film for manufacturing process; the release film for the printed circuit substrate manufacturing process at least comprises a release layer (A) and an intermediate layer (B), wherein the thickness of the release layer (A) is less than 15 mu m, and the tensile elastic modulus of the intermediate layer (B) at 180 ℃ is more than 11 MPa.

Description

Release film for printed wiring board production process, method for producing printed board, apparatus for producing printed board, and printed board

Technical Field

The first embodiment of the present invention relates to a release film used in a process of manufacturing a printed circuit board, and more particularly, to a release film suitably used in laminating a cover layer belonging to a protective layer on a surface on which an electrical circuit (copper foil or the like) is formed in manufacturing a printed circuit board.

The release film according to the first embodiment of the present invention is particularly preferably used when the printed wiring board is a flexible printed wiring board (hereinafter, also referred to as "FPC").

The second embodiment of the present invention relates to a method for manufacturing a printed circuit board, more preferably a flexible printed circuit board, and more particularly to a method for manufacturing a printed circuit board by laminating a cover layer belonging to a protective layer on a surface of a circuit base material on which an electrical circuit (copper foil or the like) is formed.

The manufacturing method according to the second embodiment of the present invention is particularly suitable for manufacturing a flexible printed circuit board in which a material film is wound from a roll (roll) and the manufactured flexible printed circuit board is wound into a roll, that is, a roll-to-roll (roll) method.

Background

In general, a substrate on which an electrical circuit is formed and a cover layer for protecting the substrate are bonded to each other with a thermosetting adhesive. When the electric circuit is formed only on one surface of the base material, the cover layer is bonded only on one surface of the base material on which the electric circuit is formed, and when the electric circuit is formed on both surfaces of the base material or in a plurality of layers, the cover layer is bonded on both surfaces of the base material. Then, in the adhesion, the substrate and the coating layer coated with the thermosetting adhesive are usually sandwiched by a metal plate, and heated and pressed. Next, in order to prevent the adhesion between the coverlay and the metal plate, a release film for FPC manufacture is inserted between the metal plate and the coverlay.

The release film for FPC production is required to have a property of releasing the film easily from the adhesive after heat curing.

From the past, release films for FPC processes have used films of fluorine-based polymers such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, and polyvinyl fluoride, films of polymethylpentene, films of polybutylene terephthalate, and the like, from the viewpoint of release properties.

In addition, in the FPC, a terminal portion of an electrical circuit is formed for electrical connection with other members, and the terminal portion is exposed without being covered with a cover layer. In addition, the adhesive applied to the coating layer to cover the portion other than the terminal is melted when being adhered by heating and pressing, and often flows out to the terminal portion of the electric circuit to form a coating layer of the adhesive, which causes a failure in electric connection. The outflow of the adhesive to the terminal portion can be prevented by filling the space exposed without being covered with the cover layer with the release film. In this case, the release film must follow the step difference between the portion covered with the cover layer and the exposed portion such as the terminal portion covered with the cover layer. That is, from the viewpoint of preventing the adhesive from flowing out to the terminal portion, the release film for FPC process is required to have following property to the unevenness formed on the FPC circuit substrate/cover laminate such as a step difference.

In addition, in the FPC process, particularly when the cover layer is bonded by heating and pressing, since the release film is subjected to a large temperature change in a relatively short time, wrinkles are likely to occur on the surface of the release film. Therefore, a problem arises in that a defective following of the release film occurs in a portion where the wrinkles are generated, or the wrinkles are transferred to the FPC, so that the FPC having a satisfactory appearance cannot be obtained.

In order to solve the above problems, a release film for FPC manufacturing process having various layer configurations and physical properties is proposed.

For example, patent document 1 proposes a film having a specific thickness composition and a heat shrinkage rate, which film includes a layer made of a 4-methyl-1-pentene copolymer having a specific composition.

However, with the development of the technology, the level of demand for release films for FPC manufacturing processes has been increasing year by year. In particular, with the increase in packaging density, the opening pattern of the cover film is miniaturized, and in order to follow this, a release film for FPC manufacturing is required to have higher followability. Further, since the circuit pattern on the printed wiring board is also miniaturized and the influence of the outflow of the adhesive to the terminal portion is relatively increased, a higher degree of followability than in the known art is required, and further, since the miniaturization of the pattern generally makes the release more difficult, the release property is also required.

In recent years, in order to improve the productivity of FPC production, a roll-to-roll method suitable for automation has been adopted. In this method, wrinkles tend to be easily generated, and hence the wrinkle resistance is required to be higher than that of the known technique.

That is, in order to meet the recent increasing demands for finer circuit patterns on printed wiring boards and higher productivity, release films for printed wiring board production processes are required to have higher followability, wrinkle resistance, and releasability than the known art.

In the printed circuit board manufacturing process, a substrate on which an electrical circuit is formed and a cover layer for protecting the substrate are generally bonded together with a thermosetting adhesive. When an electric circuit is formed only on one side of the base material, the cover layer is bonded only on one side of the base material on which the electric circuit is formed, and when the electric circuit is formed on both sides of the base material or in a plurality of layers, the cover layer is bonded on both sides of the base material. Then, in the adhesion, the substrate and the coating layer coated with the thermosetting adhesive are usually sandwiched by a metal plate, and the heating and pressing are performed through the metal plate. Then, in order to prevent the adhesion between the cover layer and the metal plate, a release film for printed circuit board manufacturing process is inserted between the metal plate and the cover layer.

In the printed circuit board manufacturing process, it is important that the printed circuit board after heat curing can be easily peeled from a release film or the like (release property).

In addition, in the printed circuit board, a terminal portion of an electrical circuit is formed for electrical connection with other members, and the terminal portion is exposed without being covered with a cover layer. Then, the adhesive applied to the coating layer to cover the portion other than the terminal is melted when the adhesive is applied by heating and pressing, and often flows out to the terminal portion of the electric circuit to form a coating layer of the adhesive, which may cause a failure in electric connection. Therefore, it is also important to prevent the outflow of the adhesive in the process of manufacturing the printed circuit board.

Further, in the printed circuit board manufacturing process, particularly when the cover layer is bonded by heating and pressing, since the release film is subjected to a large temperature change in a short time, wrinkles are likely to occur on the surface of the release film. Therefore, in the portion where the wrinkles are generated, the wrinkles are transferred to the printed board or the like, and thus there is a problem that a printed board having a sufficiently satisfactory appearance cannot be obtained. Therefore, in the process of manufacturing the printed circuit board, it is also important to have a good appearance of the printed circuit board and to prevent the generation of wrinkles of the release film.

In recent years, in order to improve productivity of printed circuit board manufacturing processes, roll-to-roll systems suitable for automation have been adopted (see, for example, patent document 2). In this method, wrinkles tend to be easily generated, and thus a higher degree of wrinkle suppression in the process of manufacturing a printed board than in the conventional art is also required.

[ Prior art documents ]

[ patent document ]

[ patent document 1] International publication No. 2008/001682A 1 booklet

[ patent document 2] Japanese patent application laid-open No. 2007-214389.

Disclosure of Invention

[ problem to be solved by the invention ]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a release film for a printed wiring board manufacturing process, particularly preferably a release film for an FPC manufacturing process, which has a high level of followability, wrinkle resistance, and release properties at a level exceeding the limit of the conventional art.

The second embodiment of the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a printed circuit board, which combines a release property, an adhesive agent outflow prevention property, and more preferably a wrinkle generation prevention property of a release film to a high degree exceeding the limit of the conventional art, and in particular, is more preferably applicable to a roll-to-roll manufacturing method.

[ means for solving the problems ]

The present applicant has made intensive studies to solve the above-mentioned problems and, as a result, has found that a release film for a printed wiring board manufacturing process, which has a laminated structure including a release layer and an intermediate layer, wherein a thickness of the release layer is equal to or less than a predetermined value, and the intermediate layer has a tensile elastic modulus equal to or more than the predetermined value, can solve the above-mentioned problems, and has completed the first embodiment of the present invention.

That is, the first embodiment and each embodiment thereof of the present invention are described in the following [1] to [8 ].

[1] The release film for manufacturing the printed circuit substrate at least comprises a release layer (A) and an intermediate layer (B),

the thickness of the release layer (A) is less than 15 μm,

the intermediate layer (B) has a tensile modulus of elasticity of 11MPa or more at 180 ℃.

[2] The release film for manufacturing a printed wiring substrate according to [1], which is used for manufacturing a flexible printed wiring substrate.

[3] The release film for the process of manufacturing a printed wiring substrate according to [1] or [2], wherein the thickness of the intermediate layer (B) is 30 μm or more.

[4] The release film for the process of manufacturing a printed wiring substrate as described in any one of [1] to [3], wherein a contact angle of a surface of the release layer (A) to water is 60 ° to 130 °.

[5] The release film for the process of manufacturing a printed wiring board according to any one of [1] to [4], wherein the release layer (A) contains at least one resin selected from the group consisting of 4-methyl-1-pentene (co) polymer, fluororesin, and polybutylene terephthalate resin.

[6] The release film for the process of manufacturing a printed wiring substrate according to any one of [1] to [5], further comprising a release layer (A ') and a layer composition comprising the release layer (A)/an intermediate layer (B)/the release layer (A').

[7] The release film for manufacturing a printed wiring substrate according to any one of [1] to [6], which is used for manufacturing a printed wiring substrate having a wiring portion with at least one of a line width and a pitch width of 100 μm or less.

[8] The release film for printed wiring substrate fabrication process according to any one of [1] to [7], which is used for printed wiring substrate fabrication process performed in a roll-to-roll manner.

The applicant has intensively studied to solve the above-mentioned problems, and found that the above-mentioned problems can be solved by combining a plurality of specific process steps with a specific release film for process, and completed the second embodiment of the present invention based on this finding.

That is, the second embodiment and more preferred embodiments of the present invention are described in the following [9] to [25 ].

[9] A method for manufacturing a printed substrate includes the steps of:

step (I), overlapping in sequence:

a circuit substrate (alpha) having a metal wiring pattern (alpha 2) formed on a resin substrate (alpha 1),

A cover layer film (β) having an adhesive layer (β 2) formed on a resin base material (β 1), and

a release film (gamma) for manufacturing process comprising a release layer (A) having a thickness of 15 [ mu ] m or less and an intermediate layer (B) having a tensile elastic modulus of 11MPa or more at 180 ℃;

a step (II) of bonding the circuit substrate (alpha) and the cover layer film (beta) by heating and pressurizing the circuit substrate (alpha) and the cover layer film (beta) so as to bond the circuit substrate (alpha) and the cover layer film (beta) by heating and pressurizing at least the cover layer film (beta) side with the release film (gamma) for process interposed therebetween; and

and (III) peeling the release film (gamma) for the process from the bonded circuit substrate (alpha) and the cover layer film (beta).

[10] The method for manufacturing a printed circuit board according to [9], wherein the printed circuit board to be manufactured is a flexible printed circuit board.

[11] The method for manufacturing a printed circuit board according to [10], wherein before the step (I), at least a part of the circuit base material (α), the cover layer film (β), and the release film (γ) for the process is wound out from a film roll,

after the step (III), the bonded circuit substrate (α) and cover layer film (β) are wound into a film roll.

[12] The method for manufacturing a printed circuit board according to [11], wherein the circuit base material (α) on which the cover layer film (β) is temporarily laminated is wound out from one film roll, and the release film (β) for the process is wound out from the other film roll.

[13] The method for manufacturing a printed substrate according to any one of [9] to [12], wherein the metal wiring pattern (α 2) has a portion in which at least one of a line width and a pitch width is 100 μm or less.

[14] The method for manufacturing a printed board according to any one of [9] to [13], wherein the cover layer film (β) has an opening, and the metal wiring pattern (α 2) is exposed through the opening in the bonded circuit substrate (α) and cover layer film (β).

[15] The method for manufacturing a printed circuit board according to any one of [9] to [14], wherein in the step (I), a process release film (γ ')/a circuit substrate (α)/a cover film (β)/a process release film (γ ') are sequentially stacked on a process release film (γ '),

in the step (II), the heating and pressing are also performed through the release film (γ') for process,

in the step (III), the release film (γ') for the process is also peeled from the bonded circuit substrate (α) and cover layer film (β).

[16] The method for manufacturing a printed board according to any one of [9] to [15], wherein the resin base material (. alpha.1) contains a polyimide resin or a polyester resin.

[17] The method for manufacturing a printed board according to any one of [9] to [16], wherein the resin base material (. beta.1) contains a polyimide resin or a polyester resin.

[18] The method for manufacturing a printed board according to any one of [9] to [17], wherein the adhesive layer (. beta.2) contains an epoxy, acrylic, polyester, or imide adhesive.

[19] The method for manufacturing a printed substrate according to any one of [9] to [18], wherein a contact angle of a surface of the release layer (A) to water is 60 ° to 130 °.

[20] A printed board manufacturing apparatus includes:

and (3) overlapping in sequence:

a unit of a release film (gamma) for manufacturing process, comprising a release layer (A) having a thickness of 15 [ mu ] m or less and an intermediate layer (B) having a tensile elastic modulus of 11MPa or more at 180 ℃;

a unit which is bonded by heating and pressurizing the circuit substrate (alpha) and the cover layer film (beta) overlapped with each other by heating and pressurizing the circuit substrate (alpha) and the cover layer film (beta) through the release film (gamma) for the process;

and a unit for peeling the release film (gamma) for the process from the bonded circuit substrate (alpha) and the cover layer film (beta).

[21] The apparatus for manufacturing a printed circuit board as recited in [20], which is used for manufacturing a flexible printed circuit board.

[22] The apparatus for manufacturing a printed circuit board according to [21], further comprising: a winding-out unit for continuously supplying the circuit substrate (alpha), a winding-out unit for continuously supplying the covering layer film (beta), and at least a part of a winding-out unit for continuously supplying the release film (gamma) for the process; and a winding unit for continuously winding the bonded circuit substrate (alpha) and cover layer film (beta).

[23] A printed substrate manufactured by the method for manufacturing a printed substrate according to any one of [9] to [19 ].

[24] An electric electronic machine, a conveying machine, or a production machine, having the printed board of [23 ].

[ Effect of the invention ]

The release film for printed wiring board manufacturing process according to the first embodiment of the present invention has high followability, wrinkle resistance, and release property, which cannot be achieved by the known techniques, and therefore, by using this, it is possible to manufacture an FPC or the like for high density packaging in various manufacturing methods such as a roll-to-roll method having high productivity while suppressing conduction failure in a terminal due to outflow of an adhesive, appearance failure due to wrinkles, and the like.

The method for manufacturing a printed circuit board according to the second embodiment of the present invention simultaneously achieves, to a high degree that cannot be achieved by known techniques, releasability, prevention of outflow of an adhesive, and more preferably prevention of occurrence of wrinkles in a release film and good appearance of the printed circuit board associated therewith, and therefore, an FPC or the like for high-density packaging is manufactured in various manufacturing methods such as a roll-to-roll method having high productivity while suppressing conduction failure in a terminal due to outflow of an adhesive, and more preferably appearance failure due to wrinkles.

Drawings

Fig. 1 is a schematic view showing an example of a release film for manufacturing process according to a first embodiment of the present invention.

Fig. 2 is a schematic view showing another example of the release film for manufacturing process according to the first embodiment of the present invention.

Fig. 3 is a schematic view showing one step in one embodiment of a method for manufacturing a printed wiring board using the release film for a process according to the first embodiment of the present invention or a method for manufacturing a printed wiring board according to the second embodiment of the present invention.

Fig. 4 is a schematic view showing another step in one embodiment of a method for manufacturing a printed wiring board using the release film for a process according to the first embodiment of the present invention or a method for manufacturing a printed wiring board according to the second embodiment of the present invention.

Fig. 5 is a schematic view showing another step in one embodiment of a method for manufacturing a printed wiring board using the release film for a process according to the first embodiment of the present invention or a method for manufacturing a printed wiring board according to the second embodiment of the present invention.

Fig. 6(a) is a perspective view schematically illustrating a method of manufacturing a printed circuit board according to a second embodiment of the present invention or a release film for manufacturing a process according to a first embodiment of the present invention. In this specification, portions (a) to (c) of fig. 6 will also collectively be referred to as "fig. 6".

Part (b) of fig. 6 is shown in fig. 6, and shows a more preferable filling state.

Part (c) of fig. 6 shows an undesirable filling state in fig. 6.

Fig. 7 is a schematic view showing a step in one embodiment of a method for manufacturing a printed wiring board using the release film for a process according to the first embodiment of the present invention.

Fig. 8 is a schematic view of a roll-to-roll method in a more preferred embodiment of a method for manufacturing a flexible printed wiring board using the release film for a process according to the first embodiment of the present invention or a method for manufacturing a printed circuit board according to the second embodiment of the present invention.

Detailed Description

The release film for manufacturing a printed circuit substrate according to the first embodiment of the present invention at least comprises a release layer (A) and an intermediate layer (B),

the thickness of the release layer (A) is less than 15 μm,

That is, the release film for a printed wiring substrate manufacturing process (hereinafter, also simply referred to as "release film") according to the first embodiment of the present invention includes a laminate film including a release layer (a) having a release property and an intermediate layer (B) supporting the release layer.

Release layer (A)

The release layer (a) constituting the release film for manufacturing process according to the first embodiment of the present invention may be made of various materials which have been used in the past as release films for manufacturing process or as release layers on the surfaces thereof. In addition, a material having a release property equivalent to those of such various materials may be used.

From the viewpoint of releasability, the contact angle of the release layer (a) to water is preferably from 60 ° to 130 °, more preferably from 90 ° to 130 °, still more preferably from 95 ° to 120 °, particularly preferably from 98 ° to 115 °, and most preferably from 100 ° to 110 °.

The release layer (a) is preferably one containing a fluororesin, a 4-methyl-1-pentene (co) polymer, a polybutylene terephthalate resin, a polystyrene resin, or the like, and more preferably one or more resins selected from the group consisting of a 4-methyl-1-pentene (co) polymer, a fluororesin, and a polybutylene terephthalate resin, from the viewpoint of excellent release properties, ease of acquisition, and the like.

The fluororesin usable for the release layer (a) may be a resin containing a constituent unit derived from tetrafluoroethylene. It may also be a homopolymer of tetrafluoroethylene, but may also be a copolymer with other olefins. Examples of other olefins include ethylene. A copolymer containing tetrafluoroethylene and ethylene as monomer constituent units is a more preferable example, and in such a copolymer, the ratio of the constituent unit derived from tetrafluoroethylene is 55 to 100 mass%, and the ratio of the constituent unit derived from ethylene is preferably 0 to 45 mass%.

The 4-methyl-1-pentene (co) polymer used in the release layer (a) may be a homopolymer of 4-methyl-1-pentene, or a copolymer of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms other than 4-methyl-1-pentene (hereinafter referred to as "olefin having 2 to 20 carbon atoms").

For example, in the case of a copolymer of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms, the olefin having 2 to 20 carbon atoms copolymerized with 4-methyl-1-pentene can impart flexibility to 4-methyl-1-pentene. Examples of the olefin having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-eicosene and the like. Such olefins may be used alone in 1 kind, or may be used in combination with 2 or more kinds.

For example, in the case of a copolymer of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms, the proportion of the constituent unit derived from 4-methyl-1-pentene is 96 to 99% by mass, and the proportion of the constituent unit derived from an olefin having 2 to 20 carbon atoms other than the constituent unit derived from 4-methyl-1-pentene is preferably 1 to 4% by mass. By reducing the content of the constituent unit derived from the olefin having 2 to 20 carbon atoms, the copolymer can be stiffened, that is, the storage elastic modulus E' can be increased, which is advantageous in suppressing the occurrence of wrinkles in the packaging step or the like. On the other hand, by increasing the content of the constituent unit derived from an olefin having 2 to 20 carbon atoms, the copolymer can be softened, that is, the storage elastic modulus E' is lowered, which is advantageous in improving the mold-following property.

The 4-methyl-1-pentene (co) polymer may be produced by a method known to those skilled in the art. For example, the catalyst can be produced by a method using a known catalyst such as a Ziegler-Natta (Ziegler-Natta) catalyst or a metallocene catalyst. The 4-methyl-1-pentene (co) polymer is preferably a (co) polymer having high crystallinity. The crystalline copolymer may be either a copolymer having an isotactic (isotactic) structure or a copolymer having a syndiotactic (syndiotic) structure, but a copolymer having a syndiotactic structure is preferable from the viewpoint of physical properties, and is also easily obtainable. Further, the 4-methyl-1-pentene (co) polymer may be formed into a film shape, and the stereoregularity or molecular weight is not particularly limited as long as it has a strength to withstand the temperature, pressure, or the like at the time of mold forming. The 4-methyl-1-pentene copolymer may be a copolymer of a vendor such as TPX (registered trademark) manufactured by Mitsui chemical Co., Ltd.

The polybutylene terephthalate resin that can be used in the release layer (a) may be any resin having a constitutional unit derived from 1, 4-butanediol and a constitutional unit derived from terephthalic acid in the skeleton, and may be polybutylene terephthalate called PBT composed of 1, 4-butanediol and terephthalic acid, or a block copolymer of polybutylene terephthalate and polyether, polyester, or polycaprolactam.

The polybutylene terephthalate resin used in the release layer (a) is preferably a raw material which is solid-phase polymerized at a temperature of 200 ℃ or higher under reduced pressure or inert gas flow. By performing solid-phase polymerization, the intrinsic viscosity at which a film is easily formed can be adjusted, and reduction in the amount of terminal carboxylic acid groups and reduction in oligomers can be expected. The Intrinsic Viscosity (IV) of the polybutylene terephthalate resin is preferably 1.0 to 1.3.

The polybutylene terephthalate resin that can be used in the release layer (a) is, for example, commercially available from TORAY under the trade name TORAYCON 1200M, TORAYCON 1100M, and commercially available from mitsubishi engineering plastics under the trade names NOVADURAN 5010CS and NOVADURAN 5020.

The melting point of the polybutylene terephthalate resin that can be used for the release layer (a) is preferably 180 to 250 ℃, more preferably 200 to 240 ℃, and still more preferably 210 to 230 ℃. The melting point of polybutylene terephthalate resin was measured by heating and melting at 300 ℃ for 5 minutes using a Differential Scanning Calorimeter (DSC), and then measuring the peak temperature of the endothermic peak accompanying melting as a melting point (Tm) (. degree. C.) in an exothermic/endothermic curve at a temperature rising rate of 10 ℃ per minute in a nitrogen gas flow using 10mg of a sample obtained by rapidly cooling with liquid nitrogen.

The polystyrene resin used in the release layer (a) contains homopolymers and copolymers of styrene, and the styrene-derived structural unit contained in the polymer is preferably at least 60 wt%, more preferably at least 80 wt%.

The polystyrene resin may be a homopolystyrene or a syndiotactic polystyrene, but the homopolystyrene is preferable from the viewpoint of transparency, easy acquisition, and the like, and the syndiotactic polystyrene is preferable from the viewpoint of releasability, heat resistance, and the like. The polystyrene may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

The thickness of the release layer (A) is 15 [ mu ] m or less. By setting the thickness of the release layer (A) to 15 μm or less, good follow-up properties can be achieved for the wiring pattern of the printed wiring board or the opening pattern of the cover layer. In view of release properties, wrinkle resistance, and the like, a release layer (a) often uses a resin having high rigidity, but even in this case, good follow-up properties can be achieved by setting the thickness of the release layer (a) to 15 μm or less, and the release properties, wrinkle resistance, and follow-up properties can be balanced to a high degree. The thickness of the release layer (A) is preferably 14 μm or less, and more preferably 13 μm or less.

The thickness of the release layer (a) is not particularly limited, but is usually 2 μm or more, preferably 3 μm or more, and more preferably 4 μm or more, from the viewpoint of ease of film formation and lamination, prevention of breakage, and the like.

The elastic modulus of the release layer (a) is not particularly limited, but from the viewpoint of release properties, wrinkle resistance, and followability to a wiring pattern or an opening pattern to a coverlay at the time of manufacturing a printed wiring board, the elastic modulus is preferably not too large or too small at the time of bonding the printed wiring board. For example, the release layer (a) has a tensile elastic modulus at 180 ℃ of 5MPa or more, more preferably 15MPa or more, from the viewpoint of mainly releasability and wrinkle resistance, and more preferably 120MPa or less, more preferably 110MPa or less, from the viewpoint of mainly followability.

In relation to the thickness, the product of the thickness of the release layer (a) and the elastic modulus is preferably within a predetermined range. More specifically, from the viewpoint of obtaining more excellent followability, the product of the thickness of the release layer (a) and the elastic modulus at 180 ℃ is preferably 1000Pa · m or less, and more preferably 900Pa · m or less. On the other hand, from the viewpoint of securing the rigidity of the film itself and obtaining more excellent wrinkle resistance, the product of the thickness of the release layer (a) and the elastic modulus at 180 ℃ is preferably 200Pa · m or more, and more preferably 250Pa · m or more.

The release layer (A) preferably has heat resistance to withstand the temperature under heat and pressure (typically 150 to 190 ℃ C.) in the production of the printed wiring substrate. From such a viewpoint, the release layer (a) preferably contains a crystalline resin having a crystalline component, and the melting point of the crystalline resin is preferably 160 ℃ or higher, and more preferably 180 ℃ or higher. The melting point of the crystalline resin is not particularly limited, but generally, the melting point of the crystalline resin is usually at most 280 ℃.

For example, it is preferable that the fluororesin contains at least a constituent unit derived from tetrafluoroethylene, the 4-methyl-1-pentene (co) polymer contains at least a constituent unit derived from 4-methyl-1-pentene, and the polystyrene resin contains at least syndiotactic polystyrene, because crystallinity is generated in the release layer (a). By containing a crystalline component in the resin constituting the release layer (a), wrinkles are less likely to occur in a resin sealing step or the like, and the occurrence of poor appearance due to transfer of wrinkles to a molded article is suitably suppressed.

The resin containing the crystalline component constituting the release layer (a) is preferably such that the resin exhibits heat resistance and release property capable of withstanding heating and pressure at the time of bonding a printed wiring board more effectively and also suppresses a dimensional change rate, and thus prevents the occurrence of wrinkles, when the amount of heat of crystal fusion in the first temperature raising step measured by Differential Scanning Calorimetry (DSC) according to jis k7221 is high. Specifically, it is preferably at least 15J/g, more preferably at least 20J/g. The amount of melting heat of the crystals in the first temperature raising step is not particularly limited, but is usually 50J/g or less.

The release layer (a) may further contain other resins in addition to the fluororesin, the 4-methyl-1-pentene copolymer, the polybutylene terephthalate resin, and/or the polystyrene resin. The elastic modulus, melting point, heat of crystal melting, and the like of the release layer (a) can be adjusted to the above-described more preferable ranges by appropriately selecting the kind and amount of addition of other resins. Examples of the other resins include polyamide-6, polyamide-66, and polyethylene terephthalate. In this way, when the release layer (a) contains a relatively large amount of a soft resin (for example, when the 4-methyl-1-pentene copolymer contains a large amount of an olefin having 2 to 20 carbon atoms), the release layer (a) can be hardened by further containing a resin having a relatively high hardness, and therefore, it is advantageous in the production of a printed wiring board to suppress the occurrence of wrinkles when a base material having an electrical circuit formed thereon and a cover layer for protecting the base material are bonded to each other.

The content of such other resin is not particularly limited as long as the releasability can be maintained, and the other resin may be contained in an amount of about 90 mass% if the surface of the fluororesin, the 4-methyl-1-pentene copolymer, the polybutylene terephthalate resin, the polystyrene resin, or the like can be localized by controlling the dispersibility.

The release layer (a) may contain known additives generally used for film resins such as heat stabilizers, weather stabilizers, rust inhibitors, copper loss stabilizers, antistatic agents, etc., in addition to high molecular resins such as fluororesins, 4-methyl-1-pentene copolymers, polybutylene terephthalate resins, polystyrene resins, etc., as long as the object of the first embodiment of the present invention is not impaired. The content of such additives may be set to, for example, 0.0001 to 20 parts by mass per 100 parts by mass of a resin such as a fluororesin, a 4-methyl-1-pentene copolymer, a polybutylene terephthalate resin, and/or a polystyrene resin.

The surface of the release layer (a) may have a concavo-convex shape as required, whereby the release property can be improved. The method for imparting unevenness to the surface of the release layer (a) is not particularly limited, but a general method such as embossing can be employed. In addition, in order to improve the release property, the surface of the release layer (a) may be subjected to a surface treatment other than the provision of the uneven shape.

Release layer (A')

The release film for manufacturing process according to the first embodiment of the present invention may further include a release layer (a') in addition to the release layer (a) and the intermediate layer (B). That is, the release film for manufacturing process according to the first embodiment of the present invention may be a release film for manufacturing process belonging to a laminate film including a release layer (a), an intermediate layer (B), and a release layer (a') in this order.

The release layer (a') may be formed of various materials conventionally used for release films for manufacturing processes or release layers on the surface thereof. In addition, a material having release properties equivalent to those of such various materials may be used.

The contact angle of the release layer (a') to water is also preferably 60 ° to 130 °, more preferably 90 ° to 130 °, more preferably 95 ° to 120 °, particularly preferably 98 ° to 115 °, most preferably 100 ° to 110 °.

The release layer (a') is preferably composed of a fluororesin, a 4-methyl-1-pentene (co) polymer, a polybutylene terephthalate resin, a polystyrene resin, or the like, and is particularly preferably composed of at least one resin selected from the group consisting of a 4-methyl-1-pentene (co) polymer, a fluororesin, and a polybutylene terephthalate resin.

The details of the more preferable resin constituting the release layer (a') are the same as those described above with respect to the release layer (a).

The thickness of the release layer (A') is preferably 15 μm or less. By setting the thickness of the release layer (a ') to 15 μm or less, good followability can be achieved even on the release layer (a') side of the release film for manufacturing process of the present embodiment. The more preferable thickness of the release layer (a') is also the same as the thickness described above with respect to the release layer (a). The thickness of the release layer (A') is preferably 14 μm or less, and more preferably 13 μm or less.

Preferable physical properties of the release layer (a') such as melting point, elastic modulus, product of elastic modulus and thickness, and heat of crystal melting are the same as those described above with respect to the release layer (a). The preferable additive components and the addition amount of the release layer (a'), and the preferable surface treatment and the like are also the same as those described above with respect to the release layer (a).

The release film for the process may have the same configuration as that of the release layer (a) and the release layer (a ') in the case of a laminate film comprising the release layer (a), the intermediate layer (B) and the release layer (a') in this order, or may have a different configuration.

The release layer (a) and the release layer (a ') are preferably of the same or slightly the same configuration from the viewpoint of preventing warpage or facilitating handling due to the same release property on either surface, and are preferably of different configurations from the viewpoint of optimum design in relation to the processes using the release layer (a) and the release layer (a '), for example, from the viewpoint of excellent release property of the release layer (a) for a printed wiring board and excellent release property of the release layer (a ') for a thermal disk.

When the release layer (a) and the release layer (a ') have different structures, the release layer (a) and the release layer (a') may be made of the same material, may have different structures such as thickness, and may have different materials and other structures.

Middle layer (B)

The intermediate layer (B) constituting the release film for manufacturing process according to the first embodiment of the present invention has the following functions: a release layer (A) (and optionally (A')) is supported and the occurrence of wrinkles in the bonding of a substrate having an electrical circuit formed thereon and a cover layer for protecting the substrate is suppressed in the production of a printed wiring board.

The resin used for the intermediate layer (B) is a resin having a buffer function for alleviating impact force when manufacturing a printed wiring board, particularly, when applying pressure and heat during FPC manufacturing.

In the release film for a process according to the first embodiment of the present invention, the intermediate layer (B) has a tensile elastic modulus of 11MPa or more at 180 ℃. Since the intermediate layer (B) has a tensile modulus of elasticity of 11MPa or more at 180 ℃, the release film for a process according to the first embodiment of the present invention can maintain high wrinkle resistance while using a relatively thin release layer (a). That is, the process release film according to the first embodiment of the present invention has both high followability due to the relatively thin release layer (a) and high wrinkle resistance due to the predetermined tensile elastic modulus of the intermediate layer (B), and is practically valuable. The intermediate layer (B) preferably has a tensile modulus of elasticity at 180 ℃ of 13MPa or more, particularly preferably over 15 MPa.

The intermediate layer (B) has a tensile modulus of elasticity at 180 ℃ not particularly limited, but is preferably 50MPa or less because it has a suitable cushioning property and gives limited unfavorable influence on the follow-up property.

The intermediate layer (B) has a tensile modulus of elasticity at 180 ℃ of 40MPa or less, more preferably 25MPa or less.

The adjustment of the tensile elastic modulus of the intermediate layer (B) at 180 ℃ can be carried out by a method generally used in the art. The material used for the intermediate layer (B) is selected as the most direct and general unit, and in particular, it is preferable to use the type of resin used for the intermediate layer (B) described later, the adjustment of blending composition at the time of blending, and the introduction of an additive having a high melting point.

The material used for the intermediate layer (B) is not particularly limited as long as the intermediate layer (B) has a tensile elastic modulus at 180 ℃ of 11MPa or more, but is preferably made of a polymer resin or contains a polymer resin as a main component, in view of flexibility, easiness in production and handling, cost, easiness in lamination with the release layer (a), and the like.

From the viewpoint of imparting the predetermined tensile elastic modulus to the intermediate layer (B), a crystalline resin having a crystalline component is preferable as the whole or a part of the polymer resin. Examples of the crystalline resin include, but are not limited to, polyolefin resins, polyester resins, polyamide resins, and polypropylene resins.

More specifically, the polyolefin resins may be copolymers, respectively, and preferably polyethylene, polypropylene, polybutylene, poly-4-methyl-1-pentene, etc., or a combination thereof is used, the polyester resin is preferably ethylene terephthalate, polybutylene terephthalate, etc., or a combination thereof is used, and the polyamide resin is preferably polyamide 6, polyamide 66, etc., or a combination thereof is used.

Among them, the use of the relatively soft polyolefin-based resin (b1) is preferable from the viewpoints of cost, variety, abundance of physical properties, ease of handling of the film, ease of lamination when the 4-methyl-1-pentene (co) polymer is used in the release layer (a), and the like. The relatively soft polyolefin resin (b1) used in the present embodiment is a polyolefin resin composed of a homopolymer or copolymer of an α -olefin having 2 to 20 carbon atoms, other than 4-methyl-1-pentene, and specifically, a resin selected from Polyethylene (PE), polypropylene (PP), polybutene, an ethylene/propylene copolymer, an ethylene/butene-1 copolymer, a propylene/butene copolymer, and the like is used alone or kneaded. Among these, polyethylene, polybutene, and ethylene/propylene copolymers are preferable.

When the polymer resin is used as the material constituting the intermediate layer (B), a composition containing a plurality of types of polymer resins (so-called resin blend) is preferably used from the viewpoint of easy adjustment of various physical properties, particularly mechanical properties such as tensile modulus at 180 ℃. In this case, it is particularly preferable to use a blend of polyolefin resins from the viewpoint of the kind of polymer resins that can be blended, the abundance of physical properties, the affinity between polymer resins over a wide composition range, and the like.

The polyolefin resins (B2) containing a high-melting-point resin, which is blended with the relatively soft polyolefin resin (B1), are preferably used as the material constituting the intermediate layer (B), and the high-melting-point resin (a) having a melting point of generally 180 ℃ or higher, more preferably 200 ℃ or higher, and particularly preferably 220 ℃ or higher. Examples of the high melting point resin (a) include poly (4-methyl-1-pentene) (co) polymer, polyester such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyamide 6, polyamide 11, and polyamide 12, which are used for the release layer (a). Among these, poly-4-methyl-1-pentene and PET are preferable, and poly-4-methyl-1-pentene is particularly preferable. The blending ratio of the polyolefin-based resin (b1) to the high-melting-point resin (a) is generally 20/80 to 98/2, and more preferably 40/60 to 95/5 in terms of the weight ratio (b 1/a).

In the case of using a blend of the polyolefin resin (B1) and the high-melting-point resin (a) as the material constituting the intermediate layer (B), it is particularly preferable that the polyolefin resin (B1) is a combination of polyethylene and polypropylene, and the high-melting-point resin (a) is a 4-methyl-1-pentene (co) polymer. That is, the material constituting the intermediate layer (B) is particularly preferably a blend of polyethylene, polypropylene and 4-methyl-1-pentene (co) polymer. In such a combination, the physical properties of the intermediate layer (B) can be desirably set with a high degree of freedom, and the release layer (a) and the intermediate layer (B) can be easily laminated when a 4-methyl-1-pentene (co) polymer is used as the release layer (a).

In the blending of polyethylene, polypropylene, and 4-methyl-1-pentene (co) polymer, the amount of 4-methyl-1-pentene (co) polymer is preferably not less than 20 parts by mass, more preferably not less than 30 parts by mass, still more preferably not less than 40 parts by mass, per 100 parts by mass in total of polyethylene, polypropylene, and 4-methyl-1-pentene (co) polymer, from the viewpoint that the tensile elastic modulus at 180 ℃ is not less than 11 MPa. In addition, the amount of the 4-methyl-1-pentene (co) polymer is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, and still more preferably 65 parts by mass or less, relative to 100 parts by mass of the total of the polyethylene, the polypropylene, and the 4-methyl-1-pentene (co) polymer, from the viewpoint of not making the tensile elastic modulus of the intermediate layer (B) at 180 ℃ excessively large, for example, 50MPa or less.

In the blending of polyethylene, polypropylene, and 4-methyl-1-pentene (co) polymer, the amount of polyethylene is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, further preferably 80 parts by mass or less, still more preferably 60 parts by mass or less, and still more preferably 50 parts by mass or less, relative to 100 parts by mass of the total of polyethylene, polypropylene, and 4-methyl-1-pentene (co) polymer, from the viewpoint of follow-up properties.

In the blending of polyethylene, polypropylene, and 4-methyl-1-pentene (co) polymer, the amount of polypropylene is preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, and further preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and still more preferably 40 parts by mass or less, relative to 100 parts by mass of the total of polyethylene, polypropylene, and 4-methyl-1-pentene (co) polymer, from the viewpoint of adhesion, compatibility, or wrinkle resistance.

The polyethylene and the polypropylene do not need to be used in both cases, and only one of them may be used.

In the resin used for the intermediate layer (B) in the present embodiment, when the polyolefin-based resin (B2) containing a high melting point resin obtained by blending the high melting point resin (a) with the polyolefin-based resin (B1) is used, the intermediate layer (B) does not melt completely even at a high temperature of, for example, about 180 ℃. Even if bleeding occurs, the adhesion of the resin to copper foil or the like is weak, and contamination of FPC or the like is easily suppressed. In addition, since the release film of this embodiment has better adhesion (follow-up property) to the step difference between the resin substrate such as a polyimide film and the wiring pattern such as a copper foil, the adhesive can be more effectively prevented from bleeding out on the wiring pattern.

As the material constituting the intermediate layer (B), a polyolefin resin/elastomer blend (B3) obtained by blending the high-melting-point resin (a) and the olefin elastomer (c) with the polyolefin resin (B1) may be used.

The olefin-based elastomer (c) used in the present embodiment is usually a polymer or copolymer of an α -olefin having 2 to 20 carbon atoms, and the density is usually 0.900g/cm³Hereinafter, more preferably, it is 0.860 to 0.900g/cm³An MFR (measured at 190 ℃ under a load of 2.16kg according to ASTM D1238) of 0.01 to 150g/10 min, more preferably 20 to l00g/10 minThe range of (1) is preferable. The olefinic elastomer (c) is preferably amorphous or has a crystallinity of less than 30% as measured by X-ray diffraction.

Examples of the α -olefin having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and mixtures thereof, among which α -olefins having 2 to 10 carbon atoms are preferable, and ethylene and 1-butene are particularly preferable.

More preferred olefin-based elastomer (c) is, specifically, a polymer or copolymer comprising, for example, 0 to 95 mol%, more preferably 30 to 92 mol%, still more preferably 50 to 90 mol% of a constituent unit derived from ethylene, 1 to 100 mol%, more preferably 4 to 70 mol%, still more preferably 8 to 50 mol% of a constituent unit derived from an α -olefin having 3 to 20 carbon atoms, and 0 to 10 mol%, more preferably 0 to 5 mol%, still more preferably 0 to 3 mol% of a constituent unit derived from a diene compound. More specifically, there may be mentioned an ethylene/α -olefin copolymer having an α -olefin content of from 10 to 50 mol% and having 3 to 10 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-l-pentene, 1-octene, 1-decene and the like, and a propylene/α -olefin copolymer having an α -olefin content of from 10 to 50 mol% and having 4 to l0 carbon atoms such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and the like.

The intermediate layer (B) may contain known additives generally blended in film resins, such as a heat stabilizer, a weather stabilizer, a rust inhibitor, a copper loss stabilizer, and an antistatic agent, in addition to the high-molecular resin such as the high-melting-point resin (a) and the relatively soft polyolefin resin (B1), within a range not to impair the object of the first embodiment of the present invention. The content of such an additive can be set to, for example, 0.0001 to 20 parts by mass relative to 100 parts by mass of the total of the polymer resins.

In one embodiment of the first embodiment of the present invention, the intermediate layer (B) may be coated with the release layer (a) around the intermediate layer.

In this embodiment, by covering the intermediate layer (B) with the generally harder release layer (a), the step of heating and pressing the FPC through the release film can be effectively prevented during the production of the printed wiring board, particularly during the production of the FPC, whereby the intermediate layer (B) of the release film can be prevented from bleeding to the outside to contaminate the FPC or the like, or the bleeding resin can be prevented from adhering to the hot plate of the press.

The intermediate layer (B) may be a non-stretched film or a stretched film, but is preferably a non-stretched film or a stretched film containing the same from the viewpoint of cushioning properties and the like, and is preferably a stretched film or a stretched film containing the same from the viewpoint of strength, anisotropy such as heat shrinkage, and the like.

The thickness of the intermediate layer (B) is not particularly limited as long as the film strength can be secured, but wrinkles can be more effectively suppressed if the thickness is large. The thickness of the intermediate layer is preferably 30 μm or more, more preferably 50 μm or more, and particularly preferably 70 μm or more. The thickness of the intermediate layer is not particularly limited, but is preferably not too large, for example, from the viewpoint of handling during winding or unwinding in the roll-to-roll process, or from the viewpoint of suppressing the amount of waste of the film, and more preferably 300 μm or less, still more preferably 200 μm or less, and particularly preferably 120 μm or less.

In relation to the thickness, the product of the thickness of the intermediate layer (B) and the elastic modulus is preferably within a predetermined range. More specifically, the product of the thickness of the intermediate layer (B) and the modulus of elasticity at 180 ℃ is preferably 1100 Pa.m or more, more preferably 1200 Pa.m or more, more preferably 1250 Pa.m or more, furthermore, 2600 Pa.m or less, more preferably 2300 Pa.m.

Layers other than

The release film for manufacturing process according to the first embodiment of the present invention may have the release layer (a) and the intermediate layer (B) (and a layer other than the release layer (a') when present) as long as it does not violate the object of the first embodiment of the present invention.

For example, when the release layer (a) (or release layer (a'))) contains a 4-methyl-1-pentene (co) polymer, the adhesive layer is preferably a modified 4-methyl-1-pentene copolymer resin graft-modified with an unsaturated carboxylic acid or the like, or an olefin adhesive resin composed of a 4-methyl-1-pentene copolymer and an α -olefin copolymer. When the release layer (a) (or release layer (a')) contains a fluororesin, the adhesive layer is preferably a polyester-based, acrylic-based, or fluororubber-based adhesive. The thickness of the adhesive layer is not particularly limited as long as the adhesion between the release layer (A) (or the release layer (A')) and the intermediate layer (B) can be enhanced, but is, for example, 0.5 to 10 μm.

In addition, the release film for manufacturing process according to the first embodiment of the present invention may have 1 or 2 or more antistatic layers, gas barrier layers, colored layers, and the like.

Release film for manufacturing process

The total thickness of the release film for process according to the first embodiment of the present invention is not particularly limited, but is, for example, preferably 35 μm or more, more preferably 50 μm or more, and still more preferably 80 μm or more, from the viewpoint of achieving both high followability and wrinkle resistance. For example, from the viewpoint of winding up in the roll-to-roll process, handling at the time of unwinding, or suppressing the amount of film discarded, for example, 320 μm or less is preferable, 200 μm or less is more preferable, and 150 μm or less is still more preferable.

Hereinafter, a more preferred embodiment of the release film for printed wiring substrate manufacturing process according to the first embodiment of the present invention will be described in more detail. Fig. 1 is a schematic view showing an example of a release film for a process having a 2-layer structure. As shown in fig. 1, the release film 11 has an intermediate layer 12 and a release layer 13 formed on one surface thereof.

The release layer 13 corresponds to the release layer (a), and the intermediate layer 12 corresponds to the intermediate layer (B). The release layer 13 is preferably disposed at least on the side in contact with the cover film in the process of manufacturing the printed wiring board, and the intermediate layer 12 is preferably disposed on the side in contact with the heat plate in the process.

FIG. 2 is a schematic view showing an example of a release film for a printed wiring substrate process having a 3-layer structure. The members having the same functions as those in fig. 1 are given the same symbols as the reciprocal one-digit numbers of their numbers. As shown in fig. 2, the release film 21 for printed wiring substrate manufacturing process has an intermediate layer 22, and

release layers

23a and 23b formed on both surfaces thereof. The release layer 23a is the release layer (a), the intermediate layer 22 is the intermediate layer (B), and the release layer 23B is the release layer (a').

The compositions of the release layers 23a and 23b may be the same or different. The thicknesses of the release layers 23a and 23b may be the same or different from each other. However, if the release layers 23a and 23b have the same composition and thickness, they are preferably symmetrical, and warpage of the release film itself is less likely to occur. In particular, the release film according to the first embodiment of the present invention is preferable to suppress warpage because stress may be generated by heating in the sealing process. In this way, when the release layers 23a and 23b are formed on both surfaces of the intermediate layer 22, good release properties can be obtained even in any one of the molded article and the inner surface of the mold, which is preferable.

Method for manufacturing release film for manufacturing process

The release film for manufacturing process according to the first embodiment of the present invention can be manufactured by any method. For example, there are: 1) a method of producing a release film for a process by coextruding and laminating the release layer (a) and the intermediate layer (B) (coextrusion forming method); 2) a method (coating method) of coating a molten resin of a resin to be the release layer (a) or the adhesive layer on the film to be the intermediate layer (B) and drying the same, or coating a resin solution of a resin to be the release layer (a) or the adhesive layer dissolved in a solvent and drying the same, to produce a release film for a process; 3) a method of manufacturing a release film for a process (lamination method) by previously manufacturing a film to be the release layer (a) and a film to be the intermediate layer (B) and laminating (laminating) these films.

In the method 3), various known lamination methods can be used for laminating the resin films, and examples thereof include an extrusion lamination method, a dry lamination method, and a heat lamination method.

The dry lamination method laminates resin films using an adhesive. The adhesive used is known as an adhesive for dry lamination. For example, it is possible to use: a polyvinyl acetate adhesive; polyacrylate adhesives composed of homopolymers or copolymers of acrylic esters (such as ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate), or copolymers of acrylic esters with other monomers (such as methyl methacrylate, acrylonitrile, and styrene); cyanoacrylate-based adhesive; ethylene copolymer adhesives composed of copolymers of ethylene and other monomers (vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid, etc.); a cellulose-based adhesive; a polyester-based adhesive; a polyamide-based adhesive; a polyimide-based adhesive; an amino resin adhesive agent composed of urea resin, melamine resin, or the like; a phenol resin adhesive; an epoxy-based adhesive; a polyurethane adhesive obtained by crosslinking a polyol (e.g., polyether polyol or polyester polyol) with an isocyanate and/or a trimeric isocyanate; a reactive (meth) acrylic adhesive; a rubber adhesive agent composed of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, or the like; a silicone adhesive; inorganic adhesives composed of alkali metal silicate, low melting point glass, etc.; other adhesives, etc. The resin film laminated by the method of 3) may be a commercially available resin film, or a resin film produced by a known production method. The resin film may be subjected to surface treatment such as corona treatment, atmospheric plasma treatment, vacuum plasma treatment, primer coating treatment, and the like. The method for producing the resin film is not particularly limited, and a known production method can be used.

1) The coextrusion molding method is preferable in that defects such as the occurrence of foreign matter can be caught between the resin layer to be the release layer (a) and the resin layer to be the intermediate layer (B), or warpage of the release film is less likely to occur. 3) The lamination method is a manufacturing method suitable for the case where an extension film is used for the intermediate layer (B). In this case, it is preferable to form an appropriate adhesive layer at the interface between the films as needed. In order to improve the adhesion between the films, the interface between the films may be subjected to surface treatment such as corona discharge treatment as needed.

The release film for manufacturing process can be uniaxially or biaxially stretched as required, whereby the film strength of the film can be improved.

The coating means in the above-described 2) coating method is not particularly limited, but various kinds of coaters such as a roll coater, a die coater, and a spray coater can be used. The melt extrusion unit is not particularly limited, but for example, an extruder having a T-die or a blow-molding die may be used.

The tensile modulus at 180 ℃ of the film or layer in the first embodiment of the invention or embodiments thereof is defined as follows.

The tensile modulus of elasticity E' was measured by a dynamic viscoelasticity measuring apparatus (for example, RSA-GII manufactured by TA instruments Co., Ltd.) and the value at 180 ℃ was taken as the tensile modulus of elasticity at 180 ℃.

Specifically, the tensile modulus E 'at 180 ℃ was determined based on data on the tensile modulus E' obtained by measuring the sample size at 5mm width and the length between chucks (MD (film length) direction) at 20mm from 30 ℃ to 200 ℃ under the measurement conditions of a frequency of 1Hz and a temperature rise rate of 3 ℃/min.

The tensile modulus at 180 ℃ of the layer in the film was measured according to the following criteria.

When a layer is taken out in a single layer state in the production process, measurement can be performed using the layer taken out in the single layer state.

Since the film is produced by coextrusion molding or the like, when a layer in a state of a single layer is not present in the production process, a single-layer film having the same thickness as that of the layer in the laminate is produced under the same conditions (molding temperature or the like), and measurement is performed using the single-layer film produced separately. However, when a single-layer film having the same thickness cannot be produced because the layer is thin in the laminate (specifically, when the thickness is 30 μm or less), a single-layer film having a thickness of 50 μm is produced under the same conditions, and measurement is performed using the single-layer film.

Process for producing a semiconductor device

The release film for process according to the first embodiment of the present invention is used in a step of laminating a circuit substrate having a metal wiring pattern formed thereon and a cover lay film constituting a printed wiring board by heating and pressing, and is disposed between the cover lay film and a hot plate or the like for heating and pressing. By using the release film for a process according to the first embodiment of the present invention, release failure to a hot plate or the like, bleeding of an adhesive on a cover film, and the like can be effectively prevented.

The adhesive on the cover film may be either a thermoplastic resin or a thermosetting resin, but thermosetting resins are widely used in this technical field, and particularly, an epoxy-based thermosetting resin is preferably used.

The process is most typically a step of integrating the circuit substrate for FPC and the cover lay film, but is not limited thereto, and the release film for process of the first embodiment of the present invention can be applied to a process of a non-flexible printed circuit board, and the like.

The details of the method for manufacturing a printed wiring board using the release film for process according to the first embodiment of the present invention and preferred embodiments thereof are the same as those described later with respect to the method for manufacturing a printed wiring board according to the second embodiment of the present invention.

The printed wiring board manufactured using the release film according to the first embodiment of the present invention has high quality and low cost, and is therefore particularly suitable for machines and devices in a wide range of fields where electronic circuits are mounted, such as electronic devices, transport machines, and production machines.

A second embodiment of the present invention is a method for manufacturing a printed circuit board, including the steps of:

step (I), overlapping in sequence:

a release film (gamma) for manufacturing process, comprising a release layer (A) having a thickness of 15 μm or less and an intermediate layer (B);

a step (II) of bonding the circuit substrate (alpha) and the cover layer film (beta) to each other by heating and pressurizing the circuit substrate (alpha) and the cover layer film (beta) to each other, at least the cover layer film (beta) side being heated and pressurized with a process release film (gamma) interposed therebetween; and

Hereinafter, a method for manufacturing a printed circuit board according to a second embodiment of the present invention will be described with reference to the drawings.

Fig. 3, 4, and 5 are schematic views showing an example of a method for manufacturing a printed circuit board according to a second embodiment of the present invention.

In fig. 3 to 5, the resin substrate 351 corresponds to the resin substrate (α 1), the metal wiring pattern 352 formed thereon corresponds to the metal wiring pattern (α 2), and the circuit substrate 35 thus constituted corresponds to the circuit substrate (α).

In fig. 3 to 5, the resin base 361 corresponds to the resin base (β 1), the adhesive layer 362 formed thereon corresponds to the adhesive layer (β 2), and the cover layer film 16 thus configured corresponds to the cover layer film (β). An opening is formed in the cover layer film, and a part of the metal wiring pattern 352 is exposed from above through the opening in an accessible manner.

In fig. 3 to 5, the release films 31a and 31B for manufacturing process correspond to release films (γ) and (γ') for manufacturing process, respectively, and include a release layer (a) and an intermediate layer (B), not shown. The release film (γ) for process is preferably used by being wound from a film roll and then wound into a film roll, and the manufacturing method of the second embodiment of the present invention is not limited to this form.

The circuit substrate 35 having the metal wiring pattern 352 formed on the resin substrate 351 and the cover film 36 having the adhesive layer 362 formed on the resin substrate 361 are overlapped so that the metal wiring pattern 352 and the adhesive layer 362 face each other (overlapping step (I), (fig. 3)). Thereafter, the adhesive layer 362 is fluidized by applying heat and pressure through the

process release films

31a and 31b, and the space in the layer of the metal wiring pattern 352 is filled with the fluidized adhesive layer, so that the space is filled between the resin substrate 351 and the resin substrate 361, and the substrates are bonded to each other (bonding step (II), (fig. 4)). Thereafter, the

release films

31a and 31b for the process are peeled from the printed circuit board of the laminated body of the circuit base material 35 and the cover layer film 36 bonded to each other, thereby producing a printed circuit board (peeling step (III), (fig. 5)).

Hereinafter, each step will be described more specifically.

Overlap procedure (I)

In the overlapping step (I) of the manufacturing method of the present embodiment, first, as shown in fig. 3, the circuit substrate 35 having the metal wiring pattern 352 formed on the resin substrate 351 and the cover film 36 having the adhesive layer 362 formed on the resin substrate 361 are overlapped so that the metal wiring pattern 352 and the adhesive layer 362 face each other.

The circuit substrate 35 and the cover film 36 that are stacked are disposed between a hot plate 37a and a hot plate 37b that supply heat and pressure for bonding. Meanwhile, release

films

31b and 31a for process are disposed between both surfaces of the circuit substrate 35 and the cover film 36, which are overlapped, and the hot plate, respectively.

In addition, the cover layer film 36 is provided with an opening pattern. As a result, as shown in fig. 3, a part of the metal wiring pattern 352 faces the opening, and is exposed from the opening even after bonding, so that the metal wiring pattern can be accessed from the outside and used as an electrode for securing conduction with the outside, for example.

In the present embodiment, the

release films

31a and 31b for manufacturing are disposed above and below the circuit substrate 35 and the cover layer film 36 which are stacked, but the use of the release film 31b for manufacturing on the lower side (the circuit substrate 35 side) is not necessary in the second embodiment of the present invention, and the form of using only the release film 31a for manufacturing on the upper side (the cover layer film 36 side) is also within the scope of the second embodiment of the present invention.

From the viewpoint of productivity, the circuit substrate 35, the cover layer film 36, and the

release films

31b and 31a supplied in the laminating step are preferably supplied from a film roll, but may be supplied in a blade shape, for example, in addition to the film roll.

Application step (II)

Next, as shown in fig. 4, the circuit substrate 35 and the cover layer film 36, which are stacked, are heated and pressed with the heat plate 37a and the heat plate 37b interposed between the

release films

31a and 31b for process.

As a result, the adhesive layer 362 flows by heating and pressing, and flows so as to fill the space in the layer of the metal wiring pattern 352. When the adhesive flows further, the space between the resin base 351 and the resin base 361 is filled with the adhesive, so that the base 351 and the base 361 are bonded, and the circuit base 35 and the cover film 36 are bonded.

The temperature during heating and pressurizing is preferably 160 ℃ or higher, particularly preferably 170 ℃ or higher. On the other hand, 200 ℃ or lower is preferred, and 190 ℃ or lower is particularly preferred.

The pressure is preferably 8MPa or more, particularly preferably 9MPa or more. On the other hand, 12MPa or less is preferred, and 11MPa or less is particularly preferred.

At this time, in the portion of the cover layer film 36 where the opening is formed, the adhesive layer 362 is not present on the resin substrate 361, and therefore the release film 31a is deformed so as to fill the space between the metal wiring pattern 352 and the resin substrate 351.

In the manufacturing method according to the second embodiment of the present invention, since the release film 31a for manufacturing process having excellent followability is used, the effect of the excellent technique of filling the space formed by the step shape is exhibited by following the step shape formed by the resin base 351, the metal wiring pattern 352, the resin base 361, and the adhesive layer 362 precisely (fig. 4).

If the following property of the release film 31a for the process is poor, the space formed by the step shape may not be filled, and there may be a problem that the adhesive from the adhesive layer 362 flows out to the unfilled space.

More specifically, fig. 6 is a perspective view of the vicinity of the opening of the cover lay film in the above embodiment.

The 6 th (a) figure shows the state in the overlaying step (I), in which a covering layer (β) composed of an adhesive layer 662 and a resin substrate 661 is overlaid on the circuit substrate (α) in which the metal wiring pattern 452 is formed on the resin substrate 451.

The cover layer film is a peripheral portion of the opening, and the opening 66b and the non-opening 66a expose the metal wiring pattern 652 in the opening 66b as shown in fig. 6 (a).

Thereafter, in the bonding step (II), the adhesive layer 662 is fluidized by heating and pressing, and flows so as to fill the space in the layer of the metal wiring pattern 652.

Part (b) of fig. 6 shows a case where filling is ideally performed, so that the space in the non-opening portion 66a is filled with the adhesive layer 662, on the other hand, outflow of the adhesive is not seen in the opening portion 66b, and the metal wiring pattern 652 is accessible (accessible) so as to cover the entire opening portion 66 b.

On the other hand, part (c) of fig. 6 shows a case where filling is not necessarily performed properly, and thus the metal wiring pattern 652 is coated with an adhesive 662' flowing out of the opening 66 b.

A typical purpose of providing an opening in the cover layer is to use a metal wiring pattern as an electrode, and to obtain electrical conduction therewith. At this time, if the adhesive flowing out is cured on the metal wiring pattern 652 in the opening portion, conduction to the metal wiring pattern 652 is hindered, and therefore, there is a possibility that the yield of the printed wiring board is lowered.

The smaller the line width and pitch width of the metal wiring pattern, in other words, the higher the integration, the greater the influence of the flowing-out adhesive, and the more complicated the shape of the irregularities to be filled, so that the flowing-out of the adhesive is likely to occur. Therefore, the manufacturing method of the second embodiment of the present invention is particularly suitable for manufacturing a printed circuit board having such a high integration.

Peeling off step (III)

When the adhesive layer 362 is made of thermosetting resin, the thermoplastic resin is cured by heating, and as shown in fig. 5, the interval between the

hot plates

37a and 37b is widened, and the bonded circuit substrate 35 and cover film 36 are taken out.

In this case, in the manufacturing method according to the second embodiment of the present invention, since the release film for process having good release property is used, the bonded circuit substrate 35 and cover layer film 36 can be taken out without applying excessive or unnecessary stress, and thus, breakage and the like of the bonded circuit substrate 35 and cover layer film 36 can be effectively suppressed. In particular, in the opening of the cover layer film 36 having a particularly complicated step shape, the shape and the pattern as designed are easily maintained.

In the case where the method of manufacturing a printed circuit board according to the second embodiment of the present invention is an FPC, it is preferable to perform the method in a roll-to-roll manner from the viewpoint of improving productivity and the like.

More specifically, for example, as shown in fig. 8, the printed circuit board to which the circuit base material 85 and the cover layer film 86 are bonded is wound into a film roll while the leaf-shaped cover layer film 86 is temporarily laminated in advance and the integrated circuit base material 85 is wound out from the film roll, whereby the FPC can be manufactured with high productivity. In this case, it is preferable to use a leaf-shaped cover film as the cover film 86 because, when this is temporarily laminated on the circuit substrate 85, misalignment with the circuit substrate during winding is less likely to occur.

In this case, it is preferable that the

release films

81a and 81b for the manufacturing process are also wound up from the film roll and supplied, and are wound up into a film roll after use and recovered.

In fig. 8, the cover layers 86 are temporarily laminated on both sides of the circuit substrate 85, but the cover layers may be temporarily laminated only on one side of the circuit substrate, or the cover layers may not be temporarily laminated, or may be supplied from a film roll different from the circuit substrate.

The circuit substrate 85 and the cover film 86 are bonded by heating and pressing 2 hot plates (87a and 87b) in the same manner as in the process described with reference to fig. 3 to 5. For example, after bonding by the same process as described above with reference to fig. 3 to 5, the circuit substrate 85, the cover film 86, and the

release films

81a and 81b for process can be transferred and bonded by the same distance as the dimension of the heat plate in the horizontal direction of the paper.

By repeating such bonding alternately, an FPC in which a circuit substrate and a cover film are bonded to each other can be manufactured with high productivity.

The printed circuit board manufacturing method according to the second embodiment of the present invention is preferable because the releasability, the prevention of the outflow of the adhesive, and more preferably the wrinkle resistance are good, and therefore, it is preferable to manufacture the FPC in a roll-to-roll manner in which wrinkles are generally easily generated at a high speed. In addition, the method is particularly preferably used in the manufacture of a highly integrated printed wiring board in which at least one of the line width and the pitch width is 100 μm or less, and in which there is a fear of adhesive bleeding or defective release, and may be used in a case where at least one of the line width and the pitch width is 50 μm or less. In addition, the case where at least one of the line width and the pitch width is 40 μm or less can be also dealt with. The lower limit of the line width or the pitch width is, for example, 10 μm.

In the manufacturing method according to the second embodiment of the present invention, the circuit substrate (α), the cover layer film (β), and the release film (γ) for the process, each having a specific configuration, are used to manufacture the printed circuit board by bonding the circuit substrate (α) and the cover layer film (β) each having a specific configuration through the above-described laminating step (I), bonding step (II), and peeling step (III).

The details of the circuit substrate (α), the coverlay film (β), and the release film (γ) for the process used in the manufacturing method according to the second embodiment of the present invention will be described below.

Circuit substrate (alpha)

The circuit substrate (α) used in the manufacturing method of the second embodiment of the present invention has a structure in which a metal wiring pattern (α 2) is formed on a resin substrate (α 1). The resin base material (. alpha.1) is preferably flexible, that is, a flexible resin base material.

Here, the material of the resin base material (α 1) is not particularly limited, and any material having flexibility and shape necessary for the purpose of use while ensuring insulation between the metal wiring patterns (α 2) can be suitably used. Among them, a material having flexibility, chemical resistance and heat resistance is preferably used.

Specific materials of the resin base material (α 1) include polyesters, polyamides, and polyimides, and particularly polyesters and polyimides are preferable in terms of balance between cost and heat resistance.

The thickness of the resin base material (. alpha.1) is not particularly limited, but is preferably 12 μm or more, particularly preferably 20 μm or more, from the viewpoint of securing strength and the like. On the other hand, from the viewpoint of flexibility, suitability for roll-to-roll processes, cost, and the like, 75 μm or less is preferable, and 50 μm or less is particularly preferable.

The metal wiring pattern (α 2) on the resin substrate (α 1) may be directly laminated on the resin substrate (α 1), or may be laminated via an adhesive.

The metal wiring pattern (α 2) can be formed by patterning the conductor layer formed on the resin substrate (α 1) by photolithography and etching.

The material of the metal wiring pattern (α 2) is not particularly limited, but a metal having excellent conductivity and workability is preferably used, and copper is particularly preferably used from the viewpoint of conductivity, workability, stability, and the like. A plating layer may be formed on the metal wiring pattern (alpha 2) by plating or the like.

The thickness of the metal wiring pattern (. alpha.2) is not particularly limited, but is preferably 9 μm or more, particularly preferably 12 μm or more, from the viewpoint of conductivity, stability and the like. On the other hand, from the viewpoint of flexibility, cost, and the like, 70 μm or less is preferable, and 35 μm or less is particularly preferable.

The line width of the metal wiring pattern (. alpha.2) is not particularly limited, but is preferably 100 μm or less, particularly preferably 90 μm or less, from the viewpoint of improving the integration degree. On the other hand, from the viewpoint of conductivity, ease of manufacturing process, and the like, 10 μm or more is preferable, and 20 μm or more is particularly preferable.

The pitch width of the metal wiring pattern (. alpha.2) is not particularly limited, but is preferably 100 μm or less, particularly preferably 90 μm or less, from the viewpoint of improving the integration. On the other hand, from the viewpoint of conductivity, ease of manufacturing process, and the like, 10 μm or more is preferable, and 20 μm or more is particularly preferable.

Overlay film (beta)

The resin base material (β 1) constituting the coverlay film (β) is not particularly limited, but for example, a polyester film or a polyimide film having the same or similar material and thickness as those of the resin base material (α 1) used for constituting the circuit base material (α) can be used.

As with the resin base material (α 1), the resin base material (β 1) is preferably also flexible, that is, a flexible resin base material is preferred.

The adhesive layer (β 2) constituting the cover layer film (β) is also not particularly limited, but an epoxy-based, acrylic, polyester-based, or imide-based adhesive is preferably used, and an epoxy-based adhesive is particularly preferably used.

The thickness of the adhesive layer (. beta.2) is not particularly limited, but is preferably 10 μm or more, particularly preferably 15 μm or more, from the viewpoint of the thickness of the metal wiring pattern, the adhesion to the metal wiring, and the like. On the other hand, from the viewpoint of preventing the outflow of the metal wiring, it is preferably 40 μm or less, and particularly preferably 35 μm or less.

The cover layer film (β) is preferably provided with an opening, and after being laminated with the circuit substrate (α), it is preferably possible to ensure electrical conduction with the metal wiring pattern (α 2) through the opening.

Release film for manufacturing process (gamma)

The release film (γ) for manufacturing process used in the manufacturing method of the second embodiment of the present invention includes at least a release layer (a) and an intermediate layer (B), and the thickness of the release layer (a) is 15 μm or less. The intermediate layer (B) preferably has a tensile modulus of elasticity at 180 ℃ of 11MPa or more.

That is, the release film (γ) for process (hereinafter, also referred to simply as "release film") has: the laminated film comprises a release layer (A) having release properties and an intermediate layer (B) supporting the release layer.

The details and preferred embodiments of the release film (γ) for manufacturing process used in the manufacturing method of the second embodiment of the present invention including the release layer (a) and the intermediate layer (B) are the same as those of the release film for manufacturing process of the first embodiment of the present invention described above.

Release film for manufacturing process (gamma')

The release film (γ') for manufacturing process is the same as the release film (γ) for manufacturing process, but is not particularly limited.

Printed circuit board manufacturing apparatus

An apparatus for manufacturing a printed circuit board according to an aspect of a second embodiment of the present invention includes:

and (3) overlapping in sequence:

a unit of a release film (gamma) for manufacturing process comprising a release layer (A) and an intermediate layer (B);

a unit which is bonded by heating and pressurizing the circuit substrate (alpha) and the cover layer film (beta) which are overlapped with each other through a release film (C) for a process;

and a unit for peeling the release film (C) for the process from the bonded circuit substrate (alpha) and the cover layer film (beta).

By using the apparatus for manufacturing a printed circuit board according to the present embodiment, a printed circuit board such as a flexible printed circuit board for high-density packaging can be manufactured with high productivity while suppressing poor conduction of terminals due to outflow of an adhesive, more preferably, poor appearance due to wrinkles.

The printed circuit board manufacturing apparatus according to the present embodiment is preferably a so-called roll-to-roll manufacturing apparatus, and further includes: a take-up unit for continuously supplying the circuit substrate (alpha), a take-up unit for continuously supplying the cover layer film (beta), and at least a part of a take-up unit for continuously supplying the release film (C) for the process; and a winding unit for continuously winding the bonded circuit substrate (alpha) and cover layer film (beta).

The roll-to-roll manufacturing apparatus according to the present embodiment can manufacture a flexible printed circuit board or the like with high productivity, and by having the above configuration, while suppressing a conduction failure of a terminal due to outflow of an adhesive agent, or more preferably, a failure in appearance due to wrinkles, or the like, a flexible printed circuit board or the like is manufactured.

The printed circuit board manufacturing method or the printed circuit board manufactured by using the manufacturing apparatus according to the second embodiment of the present invention is particularly suitable for machines and apparatuses in a wide range of fields where electronic circuits are mounted, such as electronic machines, transport machines, and production machines, because it is high in quality and low in cost.

[ examples ]

The first embodiment of the present invention will be described in more detail below with reference to examples, but the first embodiment of the present invention is not limited thereto.

In the following examples 1-1 to 1-10/comparative examples 1-1 to 1-6, evaluation of physical properties/characteristics was carried out in the following manner.

(modulus of elasticity at 180 ℃ C.)

The tensile modulus of elasticity E' was measured by a dynamic viscoelasticity measuring apparatus (RSA-GII, TA instruments Co., Ltd.) and the value at 180 ℃ was taken as the tensile modulus of elasticity at 180 ℃.

Specifically, the tensile modulus E 'at 180 ℃ was determined based on data of the tensile modulus E' obtained by measuring the sample size at 5mm width and the length between the jigs (MD (film length) direction) at 20mm from 30 ℃ to 200 ℃ under the measurement conditions of 1Hz frequency and 3 ℃/min temperature rise rate.

(measurement sample)

In the case of a layer that can be taken out in a single layer state in the manufacturing process, the measurement is performed using a layer taken out in a single layer state.

When a single layer is not present in the production process, a single layer film having the same thickness as that of the layer in the laminate is produced under the same conditions (e.g., molding temperature) and the measurement is performed using the single layer film produced separately. However, when a single-layer film having the same thickness cannot be produced because the layer in the laminate is thin (specifically, when the thickness is 30 μm or less), a single-layer film having a thickness of 50 μm is produced under the same conditions, and measurement is performed using this.

(contact Angle with Water (Water contact Angle))

The water contact angle of the surface of the release layer (A) was measured according to JIS R3257 using a contact angle measuring instrument (manufactured by Kyowa interface Science, Inc., FACECA-W).

(Release Property)

Using the apparatus having the configuration shown in fig. 7, both sides of the sheet-type cover layer film 76 were temporarily stacked on both sides of the FPC circuit substrate 75 having the metal wiring pattern formed thereon, the

release film

71a or 71b and the

glass cloth

78a or 78b of the examples/comparative examples were sequentially stacked, and the

heat plates

77a and 77b were used (however, the heat plate (77b) on one side was a rubber plate obtained by sintering and laminating a heat-resistant silicone rubber plate having a thickness of 2mm and an iron plate having a thickness of 1 mm) at a temperature: 180 ℃ and pressure: 10MPa, heating and pressurizing time: the laminate was bonded by heating and pressing for 130 seconds (prepressing: 10 seconds, body pressure: 120 seconds).

1) The circuit substrate 75 used was a polyimide film 25 μm thick and 22 μm thick copper wiring formed thereon, and the line width and pitch width of the copper wiring portion were 40 μm and 60 μm, respectively.

2) The cover film 76 used was an adhesive layer having a thickness of 25 μm formed on a polyimide film having a thickness of 12.5 μm (product name: CISV1225 DB).

The cover film 76 is perforated with a plurality of portions (openings) corresponding to the terminal portions of the circuit substrate 75 to form openings. The size of the opening of the cover film 76 was 4mm × 7 mm.

3) When the circuit substrate 75 and 2 cover layers 76 are stacked, the adhesive layer of the cover layer 76 faces the circuit substrate 75, and as a result, the copper wiring portion on the circuit substrate 75 is disposed so as to face the adhesive layer of the other cover layer 76. When the cover film 76 and the release film 71a are superposed, the former polyimide film layer and the latter release layer face each other.

Immediately after the heating and pressing, the release film was peeled off, and the releasability of the release film was evaluated according to the following criteria.

O: can be easily peeled off from FPC

And (delta): can be slightly separated from FPC with great force

X: easily attached to FPC and not peeled off

(step following property)

The evaluation of the releasability was carried out by the same combination of the device and the film, and the amount of the adhesive flowing out of the FPC on the copper wiring after heating and pressing was observed by an optical microscope, and the step following property was evaluated according to the following criteria.

O: the outflow to the opening is less than 20 μm

And (delta): the outflow rate to the opening is 20-25 μm

X: the outflow to the opening exceeds 25 μm

(anti-wrinkle)

In any of the devices having the configuration shown in fig. 8, the FPC circuit substrate 85 (in which the sheet-like cover layer films 86 are temporarily laminated on both sides in advance) having the metal wiring pattern formed thereon, which is wound out from the film roll, and the

release films

81a and 81b and the

glass cloths

88a and 88b of the examples and comparative examples were stacked in the order shown in fig. 8, and the film width was 270mm, the hot plate size: 600mm (moving direction), conveying amount: 470mm, tensile tension: 1kg, temperature: 180 ℃ and pressure: 10MPa, heating and pressurizing time: the laminate was bonded by heating and pressing for 50 seconds (preliminary pressing: 5 seconds, main pressing: 45 seconds).

The cover film 86 is temporarily laminated and wound on both surfaces of the circuit substrate 85 in advance. The conditions for temporary lamination were temperature: 40 ℃ and pressure: 0.01MPa, heating and pressurizing time: for 7 seconds.

1) The circuit substrate 85 was a copper wiring formed in a thickness of 12 μm on a polyimide film having a thickness of 25 μm, and the line width and pitch width of the copper wiring portion were 40 μm and 60 μm, respectively.

The dimension of the circuit substrate 85 per 1 unit is 250mm in width and 400mm in length in the moving direction, and the circuit substrate is a long circuit substrate in a roll of film having the same repetitive structure of the substrate pattern per 1 unit.

2) The cover film 86 is formed by using an adhesive layer having a thickness of 25 μm formed on a polyimide film having a thickness of 12.5 μm.

The cover film 86 is perforated at a plurality of portions (openings) corresponding to terminal portions of the FPC. The size of the opening of the cover film 86 is 4mm × 13 mm.

The width of the cover film 86 is 250mm, and the length in the moving direction is 380 mm.

3) When the circuit base material 85 and 2 cover layers 86 are stacked, the adhesive layer of the cover layer 86 faces the circuit base material 85, and as a result, the copper wiring on the circuit base material 85 is disposed so as to face the adhesive layer of the other cover layer 86. When the cover film 86 and the release film 81a are stacked, the former polyimide film layer and the latter release layer face each other.

After heating and pressing for 1 time, the circuit substrate 85 in a film roll, the

release films

81a and 81b and the

glass cloths

88a and 88b of the examples and comparative examples were set at a feed rate: 470mm was wound up, the second heating and pressing, and the 3 rd heating and pressing … … were repeated, the same heating and pressing were repeated for a total of 5 times, and after lamination, the release film 81a was peeled from the circuit substrate 85/cover layer laminate, and the number of wrinkles was measured and the wrinkle resistance was evaluated in accordance with the following criteria for the circuit substrate 85 on the wound release film 81a within a range of 5 times of heating and pressing in total (470 mm × 5 times in the film length direction — 2350 mm).

O: less than 25 folds

X: the corrugation is more than 25

[ example 1-1]

A resin composition was prepared by blending 60 parts by mass of a 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 8 parts by mass of a polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 32 parts by mass of a low density polyethylene resin (MIRASON F9673P, manufactured by Mitsui Dupont POLYCHEMICALS Co., Ltd.) and used as a resin for the intermediate layer (B).

As the resin for the release layer (A) and the release layer (A'), a 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.) was used.

Each extruder was charged with the above-mentioned resins by a 3-layer T-die film molding machine having 3 extruders with a screw diameter of 40mm, and the molding temperature was 280 ℃, the cooling roll temperature was 70 ℃, and the air chamber static pressure was 15mmH₂O, a laminated film consisting of 2 kinds of 3 layers having release layers (a) and (a') on both outer surfaces and an intermediate layer (B) therebetween was obtained.

After the embossing treatment was performed by contacting the film at a roll-to-roll heated preheating roll temperature of 40 ℃, both sides of the film were embossed at an embossing roll having a surface roughness Ra of 4 μm, an embossing roll temperature of 130 ℃, and an embossing line pressure of 50kg/cm, to obtain a release film of example 1 having a film surface roughness Ra of 3 μm (hereinafter, in each example/comparative example, the release film surface roughness Ra is 3 μm.). The composition of the release film is shown in Table 1-1.

Using the release film of example 1, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1-2]

The release film of example 1-2 was produced in the same manner as in example 1-1 except that the blending ratio of the resin composition used in the intermediate layer (B) was changed to 50 parts by mass of 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 10 parts by mass of polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 40 parts by mass of low density polyethylene resin (MIRASON F9673P, manufactured by Du Pont POLYCHEMICALS Co., Ltd.).

Using the release film of example 2, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1 to 3]

A release film of example 3 was produced in the same manner as in example 2, except that the thicknesses of the release layers (a) and (a') were changed to 6 μm and the thickness of the intermediate layer (B) was changed to 110 μm.

The composition of the release film is shown in Table 1-1.

Using the release films of examples 1 to 3, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1 to 4]

Release films of examples 1 to 4 were produced in the same manner as in example 1 to 2 except that the thickness of the intermediate layer (B) was changed to 80 μm.

The composition of the release film is shown in Table 1-1.

Using the release films of examples 1 to 4, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1 to 5]

Release films of examples 1 to 5 were produced in the same manner as in example 1 to 2 except that the resin used for the release layer (A) and the release layer (A ') was changed to 4-methyl-1-pentene copolymerized resin (product name: TPX, Mingren's name: MX022, manufactured by Mitsui chemical Co., Ltd.).

The tensile elastic modulus of the release layer (A) and the release layer (A') at 180 ℃ is 20MPa, and the contact angle of water is 105 degrees.

The composition of the release film is shown in Table 1-1.

Using the release films of examples 1 to 5, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1 to 6]

Release films of examples 1 to 6 were produced in the same manner as in examples 1 to 5 except that the thicknesses of the release layer (a) and the release layer (a') were changed to 5 μm and the thickness of the intermediate layer (B) was changed to 110 μm.

The composition of the release film is shown in Table 1-1.

Using the release films of examples 1 to 6, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1 to 7]

Release films of examples 1 to 7 were produced in the same manner as in examples 1 to 5 except that the resin used for the release layer (A) and the release layer (A') was changed to polybutylene terephthalate resin (product name: TORAYCON, product name: 1200M, manufactured by TORAY Co., Ltd.).

The composition of the release film is shown in Table 1-1.

Using the release films of examples 1 to 7, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1 to 8]

Release films of examples 1 to 8 were produced in the same manner as in examples 1 to 7 except that the 4-methyl-1-pentene copolymerized resin in the resin composition used for the intermediate layer (B) was changed to polybutylene terephthalate resin (product name: TORAYCON, product name: 1200M, manufactured by TORAY incorporated).

The composition of the release film is shown in Table 1-1.

Using the release films of examples 1 to 8, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1 to 9]

Release films of examples 1 to 9 were produced in the same manner as in examples 1 to 8, except that the amounts of the respective resins in the resin composition used for the intermediate layer (B) were changed as shown in table 1.

The composition of the release film is shown in Table 1-1.

Using the release films of examples 1 to 9, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

[ examples 1 to 10]

Release films of examples 1 to 10 were produced in the same manner as in example 1 to 2, except that the thicknesses of the release layer (a) and the release layer (a') were changed to 15 μm and the thickness of the intermediate layer (B) was changed to 90 μm.

The composition of the release film is shown in Table 1-1.

Using the release films of examples 1 to 10, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

Comparative examples 1 to 1

A resin composition was prepared by blending 30 parts by mass of a 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 14 parts by mass of a polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 56 parts by mass of a low density polyethylene resin (MIRASON F9673P, manufactured by Mitsui Du Pont POLYCHEMICALS Co., Ltd.) to form a film having a thickness of 70 μm, and the film was used as a resin for an intermediate layer.

As the resin for the release layer, 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.) was used.

Each extruder was charged with the above-mentioned resins by a 3-layer T-die film molding machine having 3 extruders with a screw diameter of 40mm, and the molding temperature was 280 ℃, the cooling roll temperature was 70 ℃, and the air chamber static pressure was 15mmH₂O, a laminate film consisting of 2 kinds of 3 layers with release layers on both outer surfaces and an intermediate layer (B) therebetween was obtained. The embossing treatment was performed by contacting the film at a pre-heating roll temperature of 40 ℃ heated from roll to roll, and then, at an embossing roll temperature of 130 ℃ and an embossing line pressure of 50kg/cm with a surface roughness Ra of 4 μm, to obtain a release film of comparative example 1-1. The composition of the release film is shown in Table 1-1.

Using the release film of comparative example 1-1, a laminate of a FPC circuit substrate and a blade-type cover layer film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

Comparative examples 1 and 2

A release film of comparative example 1-2 was produced in the same manner as in comparative example 1-1, except that the resin used in the release layer was changed to 4-methyl-1-pentene copolymerized resin (product name: TPX, Min shank name: MX022, manufactured by Mitsui chemical Co., Ltd.).

The composition of the release film is shown in Table 1-1.

Using the release film of comparative examples 1-2, the FPC circuit substrate and the blade cover layer film were laminated to evaluate the release property, step following property, and wrinkle resistance. The results are shown in tables 1-2.

Comparative examples 1 to 3

A release film of comparative example 1-3 was produced in the same manner as in comparative example 1-1 except that the blending ratio of the resin composition used in the intermediate layer was changed to 50 parts by mass of 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 10 parts by mass of polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 40 parts by mass of low density polyethylene resin (MIRASON F96 9673P, manufactured by Du Pont POLYCHEMICALS Co., Ltd.).

The composition of the release film is shown in Table 1-1.

Using the release films of comparative examples 1 to 3, a laminate of a FPC circuit substrate and a blade-type cover layer film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

Comparative examples 1 to 4

A release film of comparative example 1-4 was produced in the same manner as in example 1-1 except that the blending ratio of the resin composition used in the intermediate layer was changed to 35 parts by mass of 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 13 parts by mass of polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 52 parts by mass of low density polyethylene resin (MIRASON F96 9673P, manufactured by Du Pont POLYCHEMICALS Co., Ltd.).

The composition of the release film is shown in Table 1-1.

Using the release films of comparative examples 1 to 4, a laminate of a circuit substrate for FPC and a sheet-type cover lay film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

Comparative examples 1 to 5

A release film of comparative example 1-5 was produced in the same manner as in example 1-1 except that the blending ratio of the resin composition used in the intermediate layer was changed to 30 parts by mass of 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 14 parts by mass of polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 56 parts by mass of low density polyethylene resin (MIRASON F96 9673P, manufactured by Dupont POLYCHEMICALS Co., Ltd.).

The composition of the release film is shown in Table 1-1.

Using the release films of comparative examples 1 to 5, a laminate of a FPC circuit substrate and a blade-type cover layer film was formed, and the release property, step following property, and wrinkle resistance were evaluated. The results are shown in tables 1-2.

Comparative examples 1 to 6

Release films of comparative examples 1 to 6 were produced in the same manner as in comparative examples 1 to 5, except that the thickness of the release layer was changed to 20 μm and the thickness of the intermediate layer was changed to 80 μm.

The composition of the release film is shown in table 1.

[ Table 1]

[ Table 2]

Tables 1 to 2

In each example using the release film according to the first embodiment of the present invention, the release property, the step following property, and the wrinkle resistance were all good. On the other hand, in each comparative example using a release film outside the range of the first embodiment of the present invention, at least one of the release property, the step following property, and the wrinkle resistance was deteriorated.

Hereinafter, the second embodiment of the present invention will be described in more detail by way of examples, but the second embodiment of the present invention is not limited to these.

In the following examples/comparative examples, physical properties/characteristics were evaluated in the following manner.

(modulus of elasticity at 180 ℃ C.)

(measurement sample)

(contact Angle with Water (Water contact Angle))

The same procedures as described above were carried out for examples 1-1 to 1-10/comparative examples 1-1 to 1-6.

(Release Property)

Using the apparatus having the configuration shown in fig. 7, both sides of the blade-type cover layer film 76 were temporarily stacked on both sides of the FPC circuit substrate 75 having the metal wiring pattern formed thereon, the

release film

71a or 71b and the

glass cloth

78a or 78b were sequentially stacked, and the

heat plates

77a and 77b were used (however, a rubber plate obtained by baking and laminating a heat-resistant silicone rubber plate having a thickness of 2mm and an iron plate having a thickness of 1mm was provided on one side of the heat plate 77b), at a temperature: 180 ℃ and pressure: 10MPa, heating and pressurizing time: the substrates were bonded by heating and pressing for 130 seconds (prepressing: 10 seconds, main pressure: 120 seconds) to produce a flexible printed board.

1) The circuit substrate 75 used was a resin substrate (. alpha.1) in which a copper wiring having a thickness of 22 μm and belonging to a metal wiring pattern (. alpha.2) was formed on a polyimide film having a thickness of 25 μm, and the line width and pitch width of the copper wiring portion were 40 μm and 60 μm, respectively.

2) The cover film 76 used was a polyimide film belonging to the resin substrate (β 1) and having a thickness of 12.5 μm, and an adhesive layer (β 2) having a thickness of 25 μm (product name: CISV1225 DB).

The cover film 76 is perforated with a plurality of portions (openings) corresponding to the terminal portions of the circuit substrate 75. The size of the opening of the cover film 76 was 4mm × 7 mm.

3) When the circuit substrate 75 and 2 cover layers 76 are stacked, the former copper wiring layer (α 2) faces the latter 1 adhesive layer (β 2), and when the cover layer 76 and the release film 71a are stacked, the former polyimide film layer (β 1) faces the latter release layer.

After heating and pressing, the release film was peeled off immediately, and the releasability of the release film was evaluated according to the following criteria.

O: can be easily peeled off from FPC

And (delta): can be slightly separated from FPC with great force

X: easily attached to FPC and not peeled off

(prevention of adhesive flow-out)

The same combination of the device and the film as the evaluation of the releasability was observed by an optical microscope to determine whether the adhesive on the copper wiring (α 2) of the FPC after heating and pressing was prevented from flowing out according to the following criteria.

O: the outflow to the opening is less than 20 μm

And (delta): the outflow rate to the opening is 20-25 μm

X: the outflow to the opening exceeds 25 μm

(anti-wrinkle)

In any of the devices having the configuration shown in fig. 8, a circuit substrate 85 for FPC (in which a sheet-like cover layer film 86 is temporarily laminated in advance) having a metal wiring pattern formed thereon, which is wound out from a film roll, and

release films

81a and 81b,

glass cloths

88a and 88b are laminated in the order shown in fig. 8, and the film width is 270mm, and the hot plate size: 600mm (moving direction), conveying amount: 470mm, tensile tension: 1kg, temperature: 180 ℃ and pressure: 10MPa, heating and pressurizing time: the substrates were bonded by heating and pressing for 50 seconds (preliminary press: 5 seconds, main press: 45 seconds), and a flexible printed board was produced.

As described above, the cover film 86 is used by being temporarily laminated on both sides of the circuit substrate 85 in advance and wound. The conditions for temporary lamination were temperature: 40 ℃ and pressure: 0.01MPa, heating and pressurizing time: for 7 seconds.

1) The circuit substrate 85 is formed by forming a copper wiring having a thickness of 12 μm in a metal wiring pattern (α 2) on a polyimide film having a thickness of 25 μm in a resin substrate (α 1), and the line width and pitch width of the copper wiring portion are 40 μm and 60 μm, respectively.

The dimension of each unit of the circuit substrate 85 is 250mm in width and 400mm in length in the moving direction, and each unit becomes a long circuit substrate in a roll of film having a structure in which the same substrate pattern is repeated.

2) The cover film 86 is formed by using an adhesive layer (β 2) having a thickness of 25 μm formed on a polyimide film having a thickness of 12.5 μm, which is a resin substrate (β 1) (product name: CISV1225 DB).

The cover film 86 is perforated with a plurality of portions (openings) corresponding to terminal portions of the FPC. The size of the opening of the cover film 86 is 4mm × 13 mm.

3) When the circuit substrate 85 and 2 cover layers 86 are stacked, the former copper wiring layer (. alpha.2) faces the latter 1 adhesive layer (. beta.2), and when the cover layer 86 and the release film 81a are stacked, the former polyimide film layer (. beta.1) faces the latter release layer.

After heating and pressing for 1 time, the circuit substrate 85, the

release films

81a and 81b, and the

glass cloths

88a and 88b in the roll form were pressed at a conveyance rate: 470mm was wound up, the second heating and pressing, and the 3 rd heating and pressing were repeated, and after repeating the same heating and pressing for a total of 5 times to bond, the release film 81a was peeled from the circuit substrate 85/coverlay film 86 laminate, and the number of wrinkles was measured within a range of 5 times of heating and pressing of the circuit substrate 85 on the wound release film 81a (a total of 470mm × 5 times 2350mm in the film longitudinal direction), and the wrinkle resistance was evaluated in accordance with the following criteria.

O: less than 25 folds

X: the corrugation is more than 25

[ example 2-1]

A resin composition was prepared by blending 60 parts by mass of a 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 8 parts by mass of a polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 32 parts by mass of a low density polyethylene resin (MIRASON F9673P, manufactured by Mitsui Dupont POLYCHEMICALS Co., Ltd.) and used as a resin for the intermediate layer (2B).

Each extruder was charged with each of the above-mentioned trees by a 3-layer T-die film forming machine having 3 extruders having a screw diameter of 40mmFat at a forming temperature of 280 ℃, a chill roll temperature of 70 ℃ and an air chamber static pressure of 15mmH₂Under the condition of O, a laminated film consisting of 2 kinds of 3 layers with release layers (A) and (A') on both outer surfaces and an intermediate layer (B) therebetween was obtained. After the embossing treatment was performed by contacting the film at a roll-to-roll heated preheating roll temperature of 40 ℃, both sides of the film were embossed at an embossing roll having a surface roughness Ra of 4 μm, an embossing roll temperature of 130 ℃, and an embossing line pressure of 50kg/cm, to obtain a release film used in example 2-1 having a film surface roughness Ra of 3 μm (hereinafter, in each example/comparative example, the surface roughness Ra of the release film is 3 μm.). The composition of the release film is shown in Table 2-1.

Using the release film (γ), a flexible printed circuit board was produced by laminating a circuit base material (α) for FPC and a blade-type cover layer film (β) according to the above evaluation method, and the release property, adhesive flow-out, and wrinkle resistance were evaluated. The results are shown in Table 2-2.

[ examples 2-2]

The release film (. gamma.) used in example 2-2 was produced in the same manner as in example 2-1 except that the blending ratio of the resin composition used in the intermediate layer (2B) was changed to 50 parts by mass of 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 10 parts by mass of polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 40 parts by mass of low density polyethylene resin (MIRASON F9673P, manufactured by Sanyu Dupont POLYCHEMICALS Co., Ltd.). The composition of the release film is shown in Table 2-1.

[ examples 2 to 3]

A release film (γ) used in example 2-3 was produced in the same manner as in example 2-2, except that the thicknesses of the release layers (a) and (a') were changed to 6 μm and the thickness of the intermediate layer (2B) was changed to 110 μm. The composition of the release film (. gamma.) is shown in Table 2-1.

[ examples 2 to 4]

A release film (. gamma.) used in example 2-4 was produced in the same manner as in example 2-2, except that the thickness of the intermediate layer (2B) was changed to 80 μm.

The composition of the release film (. gamma.) is shown in Table 2-1.

Using this release film (γ), a flexible printed circuit board was produced by laminating a circuit base material (α) for FPC and a blade cover film (β) according to the above evaluation method, and the release property, adhesive flow-out, and wrinkle resistance were evaluated. The results are shown in Table 2-2.

[ examples 2 to 5]

A release film (. gamma.) of examples 2 to 5 was produced in the same manner as in example 2 to 2 except that the resin used for the release layer (A) and the release layer (A') was changed to 4-methyl-1-pentene copolymerized resin (product name: TPX, Minkoku corporation, Inc.: MX 022).

The composition of the release film (. gamma.) is shown in Table 2-1.

[ examples 2 to 6]

A release film (γ) used in examples 2 to 6 was produced in the same manner as in examples 2 to 5, except that the thicknesses of the release layer (a) and the release layer (a') were changed to 5 μm, and the thickness of the intermediate layer (2B) was changed to 110 μm.

The composition of the release film (. gamma.) is shown in Table 2-1.

[ examples 2 to 7]

A release film (. gamma.) used in examples 2 to 7 was produced in the same manner as in example 2 to 5 except that the resin used for the release layer (A) and the release layer (A') was changed to polybutylene terephthalate resin (product name: TORAYCON, product name: 1200M, manufactured by TORAY Co., Ltd.).

The composition of the release film (. gamma.) is shown in Table 2-1.

[ examples 2 to 8]

A release film (. gamma.) used in examples 2 to 8 was produced in the same manner as in examples 2 to 7 except that the 4-methyl-1-pentene copolymerized resin used in the resin composition for the intermediate layer (2B) was changed to polybutylene terephthalate resin (product name: TORAYCON, product name: 1200M, manufactured by TORAY GmbH.).

The composition of the release film (. gamma.) is shown in Table 2-1.

[ examples 2 to 9]

Release films (γ) used in examples 2 to 9 were produced in the same manner as in examples 2 to 8 except that the amounts of the respective resins in the resin composition used in the intermediate layer (2B) were changed as shown in table 2-1.

The composition of the release film (. gamma.) is shown in Table 2-1.

[ examples 2 to 10]

A release film (γ) used in examples 2 to 10 was produced in the same manner as in example 2 to 2, except that the thicknesses of the release layer (a) and the release layer (a') were changed to 15 μm, and the thickness of the intermediate layer (2B) was changed to 90 μm.

The composition of the release film (. gamma.) is shown in Table 2-1.

Comparative example 2-1

A resin composition was prepared by blending 30 parts by mass of a 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 14 parts by mass of a polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 56 parts by mass of a low density polyethylene resin (MIRASON F9673P, manufactured by Mitsui Du Pont POLYCHEMICALS Co., Ltd.) to form a film having a thickness of 70 μm and used as a resin for the intermediate layer (2B).

Each extruder was charged with the above-mentioned resins by a 3-layer T-die film molding machine having 3 extruders with a screw diameter of 40mm, and the molding temperature was 280 ℃, the cooling roll temperature was 70 ℃, and the air chamber static pressure was 15mmH₂Under the condition of O, a laminated film consisting of 2 types of 3 layers with release layers on both outer surfaces and an intermediate layer (B) between the release layers is obtained. Embossing roller with surface roughness Ra of 4 μm, embossing roller temperature of 130 deg.C, and embossing line pressure of 50kg/c after embossing treatment by contacting the roll-to-roll heated preheating roller temperature of 40 deg.Cm, to obtain the release film used in comparative example 2-1 having a surface roughness Ra of 3 μm. The composition of the release film is shown in Table 2-1.

Using this release film, a flexible printed board was produced by laminating a circuit base material (α) for FPC and a blade-type cover layer film (β) according to the above evaluation method, and the release property, adhesive flow-out, and wrinkle resistance were evaluated. The results are shown in Table 2-2.

Comparative examples 2 and 2

A release film used in comparative example 2-2 was produced in the same manner as in comparative example 2-1 except that the resin used in the release layer was changed to 4-methyl-1-pentene copolymerized resin (product name: TPX, Min shank name: MX022, manufactured by Mitsui chemical Co., Ltd.).

The composition of the release film is shown in Table 2-1.

Comparative examples 2 to 3

The release film used in comparative examples 2 to 3 was produced in the same manner as in comparative example 2 to 1 except that the blending ratio of the resin composition used in the intermediate layer (2B) was changed to 50 parts by mass of 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 10 parts by mass of polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 40 parts by mass of low density polyethylene resin (MIRASON F9673P, manufactured by Sanyu Dupont POLYCHEMICALS Co., Ltd.).

The composition of the release film is shown in Table 2-1.

[ reference example 2-1]

A release film used in reference example 2-1 was produced in the same manner as in example 2-1 except that the blending ratio of the resin composition used in the intermediate layer (2B) was changed to 35 parts by mass of a 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 13 parts by mass of a polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 52 parts by mass of a low density polyethylene resin (product name: MIRASON F9673P, manufactured by Du Pont POLYCHEMICALS Co., Ltd.).

The composition of the release film is shown in Table 2-1.

[ reference examples 2-2]

A release film used in reference example 2-2 was produced in the same manner as in example 2-1 except that the blending ratio of the resin composition used in the intermediate layer (2B) was changed to 30 parts by mass of 4-methyl-1-pentene copolymerized resin (product name: TPX, product name: DX818, manufactured by Mitsui chemical Co., Ltd.), 14 parts by mass of polypropylene resin (product name: F300SP, manufactured by PRIME POLYMER Co., Ltd.), and 56 parts by mass of low density polyethylene resin (product name: MIRASON F9673P, manufactured by Du Pont POLYCHEMICALS Co., Ltd.).

The composition of the release film is shown in Table 2-1.

Comparative examples 2 to 4

The release films used in comparative examples 2 to 4 were produced in the same manner as in examples 2 to 12, except that the thickness of the release layer was changed to 20 μm and the thickness of the intermediate layer (2B) was changed to 80 μm.

The composition of the release film is shown in Table 2-1.

[ Table 3]

[ Table 4]

Tables 2 to 2

In the reference examples and the manufacturing method corresponding to the second embodiment of the present invention, the result of good releasability and effective prevention of the adhesive agent from flowing out was obtained. The prevention of the outflow of the adhesive is particularly important for the quality of the product itself. In examples 2-1 to 2-10, the generation of wrinkles was also prevented. In each comparative example outside the range of the production method of the second embodiment of the present invention, although effective results are obtained from the viewpoint of partially preventing the outflow of the adhesive, the production method is not comprehensively judged to be effective from the viewpoint of preventing the occurrence of wrinkles.

[ possibility of Industrial use ]

The release film for manufacturing process of the first embodiment of the present invention has both high followability, wrinkle resistance, and mold release properties, which cannot be achieved by the known techniques, and therefore, by using this, a technical effect having high practical value is produced, which enables to manufacture an FPC or the like for high-density packaging with high productivity in high quality and by using a roll-to-roll method or the like; the present invention has a high possibility of use in various fields including the electronic component industry, the electrical and electronic industry, the mechanical industry, and the automobile industry.

The method of manufacturing a printed circuit board according to the second embodiment of the present invention has a practical and valuable technical effect of manufacturing a flexible printed circuit board for high-density packaging or the like in various manufacturing methods such as a roll-to-roll method with high productivity while suppressing conduction defects in terminals due to outflow of an adhesive agent, appearance defects due to wrinkles, and the like; the present invention has a high possibility of use in various fields including the electronic component industry, the electrical and electronic industry, the mechanical industry, and the automobile industry.

Description of the reference numerals

11,21,31a,31b,71a,71b,81a,81 b: release film for manufacturing process, and release film

12,22: intermediate layer (B), intermediate layer

13,23 a: release layer (A), release layer

23 b: a release layer (A'), a release layer

35,75,85: circuit substrate

351,651: flexible resin base material and resin base material

352,652: metal wiring pattern

36,76,86: blade-type cover lay film, cover lay film

361,661: flexible resin base material and resin base material

362,662: adhesive layer

37a,37b,77a,77b,87a,87 b: hot plate

78a,78b,88a,88 b: glass cloth

662': outflow of adhesive layer, and outflow adhesive

66 a: non-opening part

66 b: an opening portion.

Claims

1. A release film for printed circuit substrate manufacturing process at least comprises a release layer (A) and an intermediate layer (B),

the thickness of the release layer (A) is less than 15 μm,

2. The release film for manufacturing a printed wiring substrate according to claim 1, which is used for manufacturing a flexible printed wiring substrate.

3. The release film for the process of manufacturing a printed wiring substrate according to claim 1 or 2, wherein the thickness of the intermediate layer (B) is 30 μm or more.

4. The release film for the process of manufacturing a printed wiring substrate according to any one of claims 1 to 3, wherein a contact angle of the surface of the release layer (A) to water is 60 ° to 130 °.

5. The release film for the process of manufacturing a printed wiring substrate according to any one of claims 1 to 4, wherein the release layer (A) contains at least one resin selected from the group consisting of 4-methyl-1-pentene (co) polymer, fluororesin, and polybutylene terephthalate resin.

6. The release film for the process of manufacturing a printed wiring substrate according to any one of claims 1 to 5, further comprising a release layer (A ') and a layer composition comprising the release layer (A)/the intermediate layer (B)/the release layer (A').

7. The release film for printed wiring substrate manufacturing process according to any one of claims 1 to 6, which is used for manufacturing a printed wiring substrate having a wiring portion with at least one of a line width and a pitch width of 100 μm or less.

8. The release film for printed wiring substrate manufacturing process according to any one of claims 1 to 7, which is used for printed wiring substrate manufacturing process performed in a roll-to-roll manner.

9. A method for manufacturing a printed substrate includes the steps of:

step (I), overlapping in sequence:

10. The method of manufacturing a printed substrate according to claim 9, wherein the manufactured printed substrate is a flexible printed substrate.

11. The method for manufacturing a printed circuit board according to claim 10, wherein before the step (I), at least a part of the circuit base material (α), the cover lay film (β), and the release film (γ) for process is wound out from a roll of film,

12. The method for manufacturing a printed circuit board according to claim 11, wherein the circuit base material (α) on which the cover layer film (β) is temporarily laminated is wound out from one film roll, and the release film (β) for the process is wound out from the other film roll.

13. The method for manufacturing a printed substrate according to any one of claims 9 to 12, wherein the metal wiring pattern (α 2) has a portion in which at least one of a line width and a pitch width is 100 μm or less.

14. The method for manufacturing a printed board according to any one of claims 9 to 13, wherein the cover layer film (β) has an opening, and the metal wiring pattern (α 2) is exposed through the opening in the bonded circuit substrate (α) and cover layer film (β).

15. The method of manufacturing a printed circuit board according to any one of claims 9 to 14, wherein in the step (I), the process release film (γ ')/the circuit substrate (α)/the cover film (β)/the process release film (γ) are sequentially stacked with the process release film (γ'),

16. The method for manufacturing a printed substrate according to any one of claims 9 to 15, wherein the resin base material (α 1) contains a polyimide resin or a polyester resin.

17. The method for manufacturing a printed substrate according to any one of claims 9 to 16, wherein the resin base material (β 1) contains a polyimide resin or a polyester resin.

18. The method for manufacturing a printed board according to any one of claims 9 to 17, wherein the adhesive layer (β 2) contains an epoxy-based, acrylic-based, polyester-based, or imide-based adhesive.

19. The method of manufacturing a printed substrate according to any one of claims 9 to 18, wherein a contact angle of the surface of the release layer (a) to water is 60 ° to 130 °.

20. A printed board manufacturing apparatus includes:

and (3) overlapping in sequence:

21. The apparatus for manufacturing a printed circuit board according to claim 20, which is used for manufacturing a flexible printed circuit board.

22. The apparatus for manufacturing a printed circuit board according to claim 21, further comprising: a winding-out unit for continuously supplying the circuit substrate (alpha), a winding-out unit for continuously supplying the covering layer film (beta), and at least a part of a winding-out unit for continuously supplying the release film (gamma) for the process; and a winding unit for continuously winding the bonded circuit substrate (alpha) and cover layer film (beta).