JP7332017B1 - Method for manufacturing release film and molded product - Google Patents

Abstract

A mold release that can accurately suppress or prevent oxidation of a metal substrate exposed in a recess during a period from embedding a release film in a recess to releasing the release film from the recess. To provide a film and a method for producing a molded product using such a release film. A release film (10) of the present invention has a first release layer (1) made of a first thermoplastic resin composition, and a cushion layer (3) laminated on the first release layer (1). The oxygen permeability of the release film 10 measured in accordance with K 7126-2 is 60.0 cc/(m2·atm·day) or more. [Selection drawing] Fig. 4

Description

TECHNICAL FIELD The present invention relates to a release film and a method for producing a molded product.

When forming a flexible printed circuit board, that is, a laminate by bonding a coverlay film to a flexible circuit board with an exposed circuit via an adhesive layer provided on the coverlay film by a hot press, a release film is commonly used.

When forming a flexible printed circuit board using such a release film, in other words, a laminate of a flexible circuit board and a coverlay film, the release film has two properties, i.e. embeddability and release. It has been required to be excellent in formability.

In more detail, first, recesses are formed in the flexible printed circuit board by laminating a coverlay film on the flexible circuit board. Desired.

More specifically, lamination of the coverlay film on the flexible circuit board is performed via an adhesive layer provided in the coverlay film. It is required that the oozing out of the adhesive in the concave portion is suppressed by exhibiting the properties.

Moreover, after lamination of the coverlay film on the flexible circuit board as described above, the release film is required to be peeled off from the formed flexible printed circuit board with excellent releasability.

More specifically, when the release film is peeled off from the formed flexible printed circuit board, the release film exerts excellent releasability against the flexible printed circuit board, and the flexible printed circuit board is formed. It is required to suppress the occurrence of creases and breakage in.

For the purpose of making a release film excellent in the above two properties (embedding property and releasability), for example, Patent Document 1 discloses a release film having a polyester elastomer layer and a polyester layer. Proposed.

However, in consideration of manufacturing a flexible printed circuit board having better electrical properties, when a flexible printed circuit board is manufactured using a release film having such a configuration, the coverlay film, When the flexible circuit board is hot-pressed, the circuits provided on the flexible circuit board are oxidized due to the oxygen contained in the air remaining between the release film and the flexible circuit board. Therefore, it cannot be said that a flexible printed circuit board having better electrical properties has been obtained.

In addition, such a problem can be solved by applying a release film to an object made of a material containing a semi-cured thermosetting resin and placed on a metal substrate. This is also the case when a molded product is produced using an object by advancing the curing reaction of a curable resin.

JP 2011-88351 A

An object of the present invention is to accurately suppress or prevent oxidation of the metal substrate exposed in the recess during the period from embedding the release film in the recess to releasing the release film from the recess. It is to provide a release film that can be formed and a method for manufacturing a molded product using such a release film.

Such objects are achieved by the present invention described in (1) to ( 10 ) below.
(1) having a first release layer made of a first thermoplastic resin composition and a cushion layer laminated on the first release layer;
On the surface of an object formed of a material containing a thermosetting resin in a semi-cured state, placed on a metal substrate,
A release film that is used so that the surface on the first release layer side is in contact ,
The oxygen permeability of the release film, measured in accordance with JIS K 7126-2, is 100.0 cc/(m ² atm day) or more and 160.0 cc/(m ² atm day) or less. A release film characterized by the following.

(2) The release film according to (1) above, wherein the first thermoplastic resin composition contains a polyester-based resin.

(3) The release film according to (1) or (2) above, wherein the polyester resin has crystallinity, and the crystallinity of the first release layer is 10% or more and 50% or less. .

(4) The release film according to any one of (1) to (3) above, wherein the cushion layer is made of a third thermoplastic resin composition containing the polyester resin and the polyolefin resin.

(5) The release film according to any one of (1) to (4) above, wherein the first release layer has an average thickness of 7 μm or more and 38 μm or less.

(6) The release film according to any one of (1) to (5) above, wherein the cushion layer has an average thickness of 40 μm or more and 110 μm or less.

(7) The release film according to any one of (1) to (6) above, wherein the release film has an average thickness of 50 µm or more and 180 µm or less.

(8) Any one of (1) to (7) above, wherein the first release layer has a 10-point average roughness (Rz) of 0.1 μm or more and 20.0 μm or less on the surface opposite to the cushion layer. The release film described in .

(9) The release film has a second release layer made of a second thermoplastic resin composition and laminated on the side opposite to the first release layer of the cushion layer (1) to (8) ) The release film according to any one of ).

( 10 ) so that the first release layer of the release film according to any one of (1) to ( 9 ) is on the object side,
The step of placing the release film on the object, and the step of subjecting the object on which the release film is placed to a hot press, wherein the step of placing the release film includes: A method for manufacturing a molded product, wherein the surface of the object on which the release film is arranged is made of a material containing a semi-cured thermosetting resin.

According to the present invention, a release film having a first release layer made of a first thermoplastic resin composition and a cushion layer laminated on the first release layer conforms to JIS K 7126-2. It is satisfied that the oxygen permeability of the release film is 60.0 cc/(m ² ·atm · day) or more, as measured by Therefore, for example, when a flexible printed circuit board is obtained using a flexible circuit board and a coverlay film, the recess may be removed from the recess by embedding the release film in the recess and releasing the release film from the recess. It is possible to accurately suppress or prevent the oxidation of the circuit provided on the flexible circuit board, which is exposed in . Therefore, the resulting flexible printed circuit board can have better electrical properties.

FIG. 2 is a side view showing the main parts of a roll-to-roll press used for manufacturing flexible printed circuit boards; 1. It is a longitudinal cross-sectional view which shows each process in the manufacturing method of a flexible printed circuit board using the roll-to-roll press machine shown in FIG. FIG. 3 is a vertical cross-sectional view showing a heat press step in the method for manufacturing a flexible printed circuit board using the roll-to-roll press machine shown in FIG. 1; 1 is a longitudinal sectional view showing an embodiment of a release film of the present invention; FIG. FIG. 5 is a partially enlarged longitudinal sectional view partially enlarging the A portion of the release film shown in FIG. 4; Fig. 5 is a side view schematically showing a release film manufacturing apparatus for manufacturing the release film shown in Fig. 4;

BEST MODE FOR CARRYING OUT THE INVENTION A method for manufacturing a release film and a molded product according to the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.

In addition, below, the case where manufacture of a flexible printed circuit board using the release film of this invention is manufactured using a roll-to-roll press is demonstrated as an example. Prior to explaining the method for producing the release film and the molded product of the present invention, first, the roll-to-roll press used for producing the flexible printed circuit board will be explained.

<Roll-to-roll press machine>
FIG. 1 is a side view showing the main parts of a roll-to-roll press used for manufacturing flexible printed circuit boards, and FIG. FIG. 3 is a vertical cross-sectional view showing each process, and FIG. 3 is a vertical cross-sectional view showing a heat press process in a method for manufacturing a flexible printed circuit board using the roll-to-roll press machine shown in FIG. In the following, for convenience of explanation, the upper side in FIGS. ’ says.

The roll-to-roll press machine 100 (RtoR press machine) includes a release film 10, a flexible printed circuit board 200 (hereinafter sometimes referred to as "FPC"), and a conveying means (not shown) that conveys the glass cloths 300A and 300B. ), and the flexible circuit board 210 and the coverlay film 220 (hereinafter also referred to as “CL film”) included in the FPC 200, the CL film 220 is attached to the flexible circuit board 210 using the release film 10. A hot press means 50 for joining by hot pressing and a releasing means 60 for releasing (peeling) the release film 10 from the FPC 200 to which the CL film 220 is joined to the flexible circuit board 210 are provided. .

The conveying means rotates the FPC 200, the release films 10A and 10B, and the glass cloths 300A and 300B, which are respectively wound around different unwinding rollers, along their longitudinal directions by rotation of a tensioner (tension roller). , is conveyed, and after being processed by the hot press means 50 and the mold releasing means 60, it is wound around a take-up roller.

Each roller is made of a metal material such as stainless steel. Further, these rollers are arranged so that their rotation axes (central axes) face the same direction and are spaced apart from each other.

The hot press means 50 has a hot press portion 52 as shown in FIG.
The thermocompression bonding section 52 has a pair of thermocompression plates 521 . The thermocompression plate 521 is conveyed by the conveying means, facing the glass cloth 300A, the release film 10A, the FPC 200, the release film 10B, and the glass cloth 300B in a state of being superimposed, and upwardly and downwardly therefrom. placed one by one. When the glass cloth 300A, the release film 10A, the FPC 200, the release film 10B, and the glass cloth 300B, which are superimposed, pass between the heat-pressing plates 521, the heat-pressing plate 521 presses the glass. The FPC 200 is heated and pressurized via the cloths 300A, 300B and the release films 10A, 10B. Therefore, since the curing reaction of the adhesive layer 222 included in the CL film 220 proceeds due to this heating, the flexible circuit board 210 and the CL film 220, which are superimposed on each other in the FPC 200, are bonded via the adhesive layer 222. .

In other words, the coverlay 221 and the flexible circuit board 210 are bonded via the adhesive layer 222 . Further, when the FPC 200 is heated and pressurized, that is, when the coverlay 221 and the flexible circuit board 210 are joined via the adhesive layer 222, the release film 10 is inserted into the concave portion 223 formed in the coverlay 221. will be embedded. Therefore, the seepage of the adhesive originating from the adhesive layer 222 in the concave portion 223 is suppressed (see FIG. 2B).

Note that the FPC 200 is in a laminated state by overlapping the flexible circuit board 210 and the CL film 220 before being thermocompression bonded by the thermocompression bonding plate 521 . and are not joined through the adhesive layer 222 of the CL film 220 . Then, the adhesive layer 222 provided in the CL film 220 is brought into close contact with the flexible circuit board 210 by pressure bonding by the thermocompression plate 521 , and further, in this state, by heating by the thermocompression plate 521 , the curing reaction of the adhesive layer 222 is initiated. By proceeding, the flexible circuit board 210 and the CL film 220 are bonded via the adhesive layer 222 .

As shown in FIG. 1, the releasing means 60 is arranged downstream of the hot pressing means 50 in the conveying direction. The release means 60 is configured to separate the FPC 200 and the release films 10A and 10B. Here, the release film 10 is embedded in the concave portion 223 formed in the coverlay 221 in the thermocompression bonding portion 52 provided in the heat press means 50, whereby the release film 10 is attached to the CL film 220 (FPC 200). Although they are joined, the release means 60 is configured to allow the release film 10 to be peeled off (released) from the CL film 220 (FPC 200) (see FIG. 2(c)). Therefore, the FPC 200 having the configuration in which the flexible circuit board 210 and the CL film 220 are bonded via the adhesive layer 222 is obtained in a state of being separated from the release film 10 by the action of the release means 60. It will happen.

A flexible printed circuit board 200 (FPC 200) can be manufactured using the roll-to-roll press machine 100 as described above. A method of manufacturing the FPC 200 using this roll-to-roll press will be described below. It should be noted that the method for manufacturing a molded product of the present invention is applied to the method for manufacturing this FPC 200 .

In the present embodiment, the FPC 200 is manufactured by stacking a sheet-shaped glass cloth 300A, a release film 10A, the FPC 200, a release film 10B, and a glass cloth 300B in this order. In the first step of forming a laminated body in a state and by heat-pressing the laminated body, in the FPC 200, the coverlay 221 (CL film 220) is attached to the flexible circuit board 210 via the adhesive layer 222. a second step of bonding; and a third step of releasing the release films 10 (10A, 10B) from the FPC 200 to obtain the FPC 200 in which the CL film 220 is bonded to the flexible circuit board 210. .

Each of these steps will be described below in sequence.
(First step)
First, the sheet-shaped glass cloth 300A, the release film 10A, the FPC 200, the release film 10B, and the glass cloth 300B wound around the unwinding roller are conveyed by the conveying means. Then, a layered product is obtained in which the layers are superimposed in this order (step of disposing release film, see FIGS. 1, 2(a), and 3).

The method of laminating each member (film) on the laminate is not particularly limited, and for example, lamination may be performed while pressing with a roll or while pressing with a press. Also, the order of laminating each member can be arbitrarily set. For example, all members may be laminated at the same time, or the coverlay film 220 and the flexible circuit board 210 may be laminated in advance, and then the other members may be laminated at the same time.

Further, the formation of the laminate in the first step constitutes the step of disposing the release film 10 on the object (FPC 200) in the method of manufacturing a molded product of the present invention.

(Second step)
Next, a laminated body in which the glass cloth 300A, the release film 10A, the FPC 200, the release film 10B, and the glass cloth 300B are superimposed in this order is pressed by the heat press means 50 (heat press bonding portion 52). By applying heat (heating press) while applying pressure, the curing reaction of the adhesive layer 222 proceeds while the adhesive layer 222 is in close contact with the flexible circuit board 210 . The coverlay 221 (CL film 220) is bonded to the substrate via the adhesive layer 222 to form a bonded body (heat press step, see FIGS. 1, 2(b) and 3).

At this time, since the release film 10A is embedded in the recess 223 formed in the coverlay 221 while the release film 10A is in close contact with the coverlay 221, the adhesive layer in the recess 223 222-derived adhesive is suppressed.

The height of the step formed in the concave portion 223 of the FPC 200 (coverlay 221) is set to approximately 30 μm or more and 100 μm or less when the FPC 200 is applied to a vehicle. .

In the second step (heat press step), the temperature for heating the FPC 200 is not particularly limited. .

Also, in the second step, the pressure set in the thermocompression bonding unit 52 when pressurizing the FPC 200 is not particularly limited, but is preferably 1 MPa or more and 14 MPa or less, more preferably 5 MPa or more and 14 MPa or less. be done.

Further, the transport speed for transporting the laminate is preferably set to 40 mm/sec or more and 400 mm/sec or less, more preferably 100 mm/sec or more and 350 mm/sec or less. In other words, in the second step (main step), the laminate is hot-pressed using the hot press means 50, and in the peeling step (next step), the release film 10 is peeled from the joined body. The close contact time up to is preferably set to 1.0 sec or more and 10.0 sec or less, more preferably 4.0 sec or more and 7.0 sec or less. It can be said that the FPC 200 is manufactured efficiently by setting the transport speed, ie, the contact time, within such a range. That is, it can be said that the FPC 200 is manufactured with excellent productivity.

Note that the second step constitutes a step of hot pressing the object (FPC 200) on which the release film 10 is arranged in the method for manufacturing a molded product of the present invention. In addition, when the coverlay 221 (insulating layer) is made of a material containing a semi-cured thermosetting resin, the surface of the object (FPC 200) on which the release film 10 is arranged is covered. Ray 221 configures. Since the release film 10 is overlaid on the surface of the coverlay 221 so that the surface on the side of the first release layer 1 is in contact with the coverlay 221 , the release film 10 forms the coverlay with the concave portions 223 . Since the thermosetting resin can be cured while maintaining the shape of 221, the coverlay 221 (molded product) can be molded on the flexible circuit board 210 with excellent accuracy. In addition, since the adhesion time is set within the above range, the release film 10 maintains the shape of the coverlay 221 with the recesses 223 formed therein, and the thermosetting resin forming the coverlay 221 is removed. Curing reaction can proceed.

Furthermore, in the present embodiment, the means for heating by means of a heat press is shown, but the method is not necessarily limited to this method. For example, heating by infrared rays or heating by a heating roll may be performed.

From such a second step (heat press step) to the release of the release film 10 from the FPC 200 in the next step, the third step (release step), the release film 10 is applied to the FPC 200. 10 is attached. At this time, the present invention satisfies that the oxygen permeability of the release film 10 measured in accordance with JIS K 7126-2 is 60.0 cc/(m ² ·atm · day) or more. . Therefore, between the second step (main step) and the release film 10 in the third step (next step), as described above, in the second step (main step), the FPC 200 is Even if it is hot-pressed, it is possible to accurately suppress or prevent oxidation of the circuit provided in the flexible circuit board 210 exposed in the recess 223, so that the obtained FPC 200 has better electrical properties. A detailed description will be given later.

(Third step)
Next, the release film 10 (10A, 10B) is released from the FPC 200 by the release means 60. Next, as shown in FIG. That is, the release film 10A and the release film 10B are separated from the joined body of the coverlay film 220 and the flexible circuit board 210 . As a result, the FPC 200 in which the CL film 220 is joined to the flexible circuit board 210 is obtained (separation step, see FIGS. 1, 2(c) and 3).

The releasing means 60 is not particularly limited. For example, it may be configured such that a vacuum device is installed on the outside, and the bonded body and the release film 10A are separated by vacuuming. It may be of a configuration in which air is sent between 10B to separate them, or a configuration in which a stick is sandwiched between the joined body and the release films 10A and 10B for separation may be used.

After that, the joined body of the coverlay film 220 and the flexible circuit board 210, the glass cloth 300A, the release film 10A, the release film 10B, and the glass cloth 300B are wound up by respective winding rollers.

By such winding, the flexible circuit board 210 and the CL film 220 are continuously obtained as the FPC 200 bonded via the adhesive layer 222 of the CL film 220 while being wound on the winding roller. will be

As described above, the flexible printed circuit board 200 is continuously manufactured by applying the manufacturing method of the flexible printed circuit board 200 by the roll-to-roll press machine 100 using the release film 10 .

After the third step, the flexible printed circuit board 200 wound on the winding roller, or the wound flexible printed circuit board 200 cut into individual sheets is used. A step of curing the coverlay 221 by further advancing the curing reaction of the thermosetting resin forming the coverlay 221 by heating in an oven or the like may be included.

The release film of the present invention is applied to the release film 10 used for manufacturing this flexible printed circuit board 200 . The release film 10 to which the release film of the present invention is applied will be described below.

<Release film 10>
FIG. 4 is a vertical cross-sectional view showing an embodiment of the release film of the present invention, and FIG. 5 is a partially enlarged vertical cross-sectional view partially enlarging part A of the release film shown in FIG.
As shown in FIG. 4, in the present embodiment, the release film 10 is composed of a laminate in which a first release layer 1, a cushion layer 3, and a second release layer 2 are laminated in this order. The CL film 220 included in the FPC 200 is overlapped so that the surface on the first release layer 1 side is in contact with the CL film 220 .

In the present invention, the release film 10 has an oxygen permeability of 60.0 cc/(m ² ·atm · day) or more, which is measured according to JIS K 7126-2. things are used.

Here, as described above, in the method for manufacturing the flexible printed circuit board 200 using the release film 10, compatibility between embedding of the release film 10 in the concave portion 223 and releasability from the flexible printed circuit board 200 is achieved. Further, it is required that the FPC 200 having better electrical properties be manufactured.

However, between the second step (main step) and the release film 10 in the third step (next step), as described above, the FPC 200 is removed in the second step (main step). During the hot pressing, the circuit included in the flexible circuit board 210 is oxidized based on the oxygen contained in the air remaining between the release film 10 and the FPC 200, resulting in the FPC 200 having better electrical properties. The problem was that I couldn't get it.

In response to such problems, in the present invention, the release film 10 has an oxygen permeability of 60.0 cc/(m ² ·atm·day) or more is selected. That is, the release film 10 is selected to have excellent oxygen permeability in the thickness direction. Therefore, between the second step (main step) and the release film 10 in the third step (next step), as described above, the FPC 200 is removed in the second step (main step). Oxygen remaining between the release film 10 and the FPC 200 can permeate through the release film 10 during hot pressing. Therefore, even if the FPC 200 is heated when the FPC 200 is heated and pressed, it is possible to accurately suppress or prevent the circuits of the flexible circuit board 210 exposed in the recesses 223 from being oxidized. Therefore, the obtained FPC 200 can have better electrical properties.

Each layer constituting the release film 10 will be described below.
<Cushion layer 3>
First, the cushion layer 3 will be explained. This cushion layer 3 is arranged as an intermediate layer between the first release layer 1 and the second release layer 2 .

The cushion layer 3 is made of a third thermoplastic resin composition, and the third thermoplastic resin composition provides the release film 10 with embedding properties in the concave portions 223 and increases the oxygen permeability of the release film 10. For the purpose of setting the lower limit or more, in the present invention, one containing a plurality of types of thermoplastic resins is preferably used.

Combinations of a plurality of types of thermoplastic resins include, for example, combinations of polyester resins and polyolefin resins, combinations of polyolefin resins, and combinations of polyamide resins and polyolefin resins. By selecting the combination of the polyester resin and the polyolefin resin, the oxygen permeability of the release film 10 can be relatively easily set to the above lower limit or higher.

The polyester-based resin is not particularly limited, but examples include polyethylene terephthalate (PET), polycyclohexane terephthalate (PCT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycyclohexanedimethylene terephthalate, polypropylene terephthalate, and the like. and one or more of these can be used in combination. When two or more of these are used in combination, the polyester resin may be a blend or a copolymer thereof. Among these, the polyester-based resin is particularly preferably polybutylene terephthalate. As a result, the cushion layer 3 can be provided with excellent conformability to the concave portion 223 . Further, when the first thermoplastic resin composition constituting the first release layer 1 contains polybutylene terephthalate, the cushion layer 3 exhibits excellent adhesion to the first release layer 1. can be Furthermore, the oxygen permeability of the release film 10 can be more easily set to the above lower limit or higher.

Furthermore, although this polyester resin exhibits crystallinity, it is preferable that the crystallization of the cushion layer 3 is suppressed or prevented. As a result, the oxygen permeability of the release film 10 can be more easily set to the lower limit value or higher.

The polyolefin resin is not particularly limited, and examples include polyethylene such as low-density polyethylene and high-density polyethylene, α-olefin polymers such as polypropylene, ethylene, propylene, butene, pentene, hexene, octene, and the like. as a polymer component, copolymers of ethylene and hexene, copolymers of ethylene and octene, copolymers of α-olefins and (meth)acrylic acid esters, copolymers of ethylene and vinyl acetate , α-olefin copolymers such as copolymers of ethylene and (meth)acrylic acid, and the like, and these may be used alone or in combination of two or more. Among these, at least one of a copolymer of ethylene and vinyl acetate (ethylene vinyl acetate copolymer) and a copolymer of ethylene and (meth)acrylic acid (ethylene (meth)acrylic acid copolymer) Seeds are preferred. As a result, the cushion layer 3 can be provided with excellent conformability to the concave portion 223 . In addition, the oxygen permeability of the release film 10 can be more easily set to the lower limit value or higher.

When a combination of a polyester resin and a polyolefin resin is used, the content of the polyester resin in the third thermoplastic resin composition is preferably 5 wt% or more, and 8 wt% or more and 40 wt% or less. is more preferable. As a result, it is possible to provide the release film 10 with excellent conformability to the concave portions 223 . In addition, the oxygen permeability of the release film 10 can be more easily set to the lower limit value or higher.

In addition to the resin material (thermoplastic resin) described above, the third thermoplastic resin composition constituting the cushion layer 3 contains an antioxidant, a slip agent, an antiblocking agent, an antistatic agent, a coloring agent, a stabilizing agent, and an antioxidant. Additives such as agents may also be included.

Furthermore, the storage elastic modulus E′ of the cushion layer 3 at 150° C. is preferably 0.1 MPa or more, more preferably 0.5 MPa or more and 150 MPa or less, and more preferably 1.0 MPa or more and 100 MPa or less. More preferred. By setting the storage elastic modulus E′ of the cushion layer 3 at 150° C. as described above, when the release film 10 is embedded in the concave portion 223 in the second step, the edges of the release film 10 Therefore, it is possible to accurately suppress or prevent part of the cushion layer 3 from protruding and adhering to the FPC 200 . Therefore, contamination of the FPC 200 can be appropriately suppressed or prevented. Moreover, it is possible to easily peel off the release film 10 in the third step.

In addition, the storage elastic modulus E' of the cushion layer 3 at 150 ° C. is measured, for example, by preparing a cushion layer 3 having a width of 4 mm and a length of 20 mm according to JIS K7244-4, and using a dynamic viscoelasticity measuring device (Hitachi High Tech Science Co., Ltd., "DMA7100"), it can be obtained by measuring at a tension mode, a frequency of 1 Hz, and a heating rate of 5°C/min.

Further, the cushion layer 3 preferably has an average thickness Tk of 40 μm or more and 110 μm or less, more preferably 50 μm or more and 90 μm or less. As a result, the oxygen permeability of the release film 10 can be relatively easily set to the lower limit value or higher.

<First release layer 1>
Next, the first release layer 1 is described. The first release layer 1 is laminated on one side of the cushion layer 3 .

The first release layer 1 is flexible, and in the method for manufacturing the flexible printed circuit board 200 using the release film 10 described above, the first release layer Release films 10 are superimposed so that 1 is in contact. Then, in the second step of this manufacturing method, when the flexible circuit board 210 and the CL film 220 that are overlaid are joined via the adhesive layer 222, the flexible circuit board 210 and the CL film 220 are bonded together. It is a layer that follows the shape of the formed concave portion 223 and is pushed in, and functions as a protective (buffer) material that prevents the release film 10 from breaking. Furthermore, the first release layer 1 functions as a contact layer for exhibiting excellent releasability of the release film 10 from the CL film 220 (FPC 200) in the third step. .

Therefore, it is possible to accurately suppress or prevent the adhesive originating from the adhesive layer 222 from seeping into the concave portions 223 formed in the FPC 200 in the second step. Further, after forming the FPC 200 in which the flexible circuit board 210 and the CL film 220 are bonded via the adhesive layer 222 provided in the CL film 220 in the second step, in the third step, from the FPC 200 When the release film 10 is peeled off, the FPC 200 can be accurately suppressed or prevented from being stretched and broken. Moreover, when the third thermoplastic resin composition constituting the cushion layer 3 contains a polyester-based resin, the first release layer 1 can exhibit excellent adhesion to the cushion layer 3 .

In addition, the first release layer 1 is in contact with the CL film 220 included in the FPC 200 in the manufacturing method of the flexible printed circuit board 200 . Therefore, in the second step of this manufacturing method, it also has a function of transferring heat from the thermocompression plate 521 to the CL film 220 when the FPC 200 is hot pressed.

This first release layer 1 is made of a first thermoplastic resin composition. Moreover, it is preferable that the first thermoplastic resin composition mainly contains a polyester-based resin, for example. This makes it possible to impart the above-described functions to the first release layer 1 relatively easily. Furthermore, the oxygen permeability of the release film 10 can be relatively easily set to the lower limit value or higher.

In addition, the polyester resin is not particularly limited, but for example, the same ones as those mentioned in the third thermoplastic resin composition can be used, and among them, polybutylene terephthalate (PBT) is particularly preferred. is preferred. Thereby, the effect obtained by using the polyester-based resin can be exhibited more remarkably. Moreover, when the third thermoplastic resin composition constituting the cushion layer 3 contains polybutylene terephthalate, the first release layer 1 can exhibit excellent adhesion to the cushion layer 3 . Furthermore, the oxygen permeability of the release film 10 can be more easily set to the above lower limit or higher.

Furthermore, the polyester-based resin exhibits crystallinity, and the first release layer 1 made of this polyester-based resin preferably has its crystallization suppressed. is preferably about 10% or more and 50% or less, more preferably about 10% or more and 35% or less. As a result, the oxygen permeability of the release film 10 can be more easily set to the lower limit value or higher.

The crystallization of the resin material exhibiting crystallinity such as the polyester-based resin in the release layers 1 and 2 and the cushion layer 3 is, for example, in the method of manufacturing the release film 10 described later, in a melted or softened strip shape. The cooling temperature for cooling the film 10' can be set within the following range.

Further, when the first thermoplastic resin composition is mainly composed of a polyester-based resin, it may contain a thermoplastic resin other than the polyester-based resin. Examples of the thermoplastic resin include polyethylene, polypropylene, Polyolefin-based resins such as poly-4-methyl-1-pentene, polystyrene-based resins such as syndiotactic polystyrene, and the like can be mentioned, and one or more of these can be used in combination.

Moreover, the first thermoplastic resin composition may further contain at least one of inorganic particles and organic particles in addition to the thermoplastic resin described above.

Examples of inorganic particles include, but are not limited to, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, alumina, aluminum nitride, aluminum borate whiskers, Boron nitride, crystalline silica, amorphous silica, antimony oxide, E glass, D glass, S glass, etc., may be mentioned, and one or more of these may be used in combination.

The organic particles are not particularly limited, but include, for example, polystyrene particles, acrylic particles, polyimide particles, polyester particles, silicone particles, polypropylene particles, polyethylene particles, fluororesin particles and core-shell particles. It can be used alone or in combination of two or more.

Furthermore, the inorganic particles and the organic particles preferably have an average particle size of 3 μm or more and 20 μm or less, more preferably 5 μm or more and 20 μm or less. As a result, when at least one of inorganic particles and organic particles is contained in the first thermoplastic resin composition, the surface roughness of the surface of the first release layer 1 opposite to the cushion layer 3 is It can be relatively easily set within the range described later.

When the first release layer 1 has an uneven shape on its surface, the 10-point average roughness (Rz) on the surface is preferably 0.1 μm or more and 20.0 μm or less, and 1.0 μm or more and 10.0 μm. The following are more preferable. As a result, when the release film 10 is released from the FPC 200 (flexible circuit board 210), the release can be performed with excellent releasability. The 10-point average roughness (Rz) can be measured according to JIS B 0601-1994.

In addition, the first release layer 1 having such a structure preferably has a storage modulus E′ at 150° C. of 50 MPa or more, more preferably 50 MPa or more and 1000 MPa or less, and 50 MPa or more and 300 MPa or less. is more preferred. Thereby, the function as the first release layer 1 described above can be reliably imparted to the first release layer 1 .

The storage elastic modulus E′ of the first release layer 1 at 150° C. is determined by preparing the first release layer 1 having a width of 4 mm and a length of 20 mm in accordance with JIS K7244-4, and dynamic viscoelasticity measurement. It can be obtained by measuring with a device (“DMA7100” manufactured by Hitachi High-Tech Science Co., Ltd.) in a tension mode, a frequency of 1 Hz, and a heating rate of 5° C./min.

The average thickness T1 of the first release layer 1 is preferably set to 7 μm or more and 38 μm or less, and more preferably set to 10 μm or more and 30 μm or less. As a result, the average thickness of the first release layer 1 is set within an appropriate range, so that the function of the first release layer 1 described above can be imparted to the first release layer 1 more reliably. can be done. In addition, the oxygen permeability of the release film 10 can be relatively easily set to the lower limit value or higher.

As described above, when the surface of the first release layer 1 on the side opposite to the cushion layer 3 has an uneven shape, the thickness of the first release layer 1 is the position including the protrusions, and The thickness of each recess is measured at a position including the recess.

In addition, the first thermoplastic resin composition constituting the first release layer 1 may contain, in addition to the above-described resin material, inorganic particles, and organic particles, the same materials as those listed for the third thermoplastic resin composition. Additives may be included.

<Second release layer 2>
Next, the second release layer 2 is described. The second release layer 2 is laminated on the other side of the cushion layer 3 , that is, on the side of the cushion layer 3 opposite to the first release layer 1 .

The second release layer 2 has flexibility. are in contact with each other, and in the second step of this manufacturing method, the laminated flexible circuit board 210 and CL film 220 are bonded via an adhesive layer 222. It functions as a layer that transmits the force from the thermocompression plate 521 to the cushion layer 3 when the pressure is applied. Furthermore, the second release layer 2 functions as a contact layer for exhibiting excellent release properties between the glass cloth 300 and the release film 10 in the third step.

Further, in the manufacturing method of the flexible printed circuit board 200 , the second release layer 2 is in contact with the thermocompression plate 521 via the glass cloth 300 . Therefore, in the second step of this manufacturing method, the FPC 200 also has a function of transferring the heat from the thermocompression plate 521 to the cushion layer 3 when the FPC 200 is hot-pressed.

The second release layer 2 is made of a second thermoplastic resin composition. Moreover, it is preferable that this second thermoplastic resin composition mainly contains a polyester-based resin, similarly to the first thermoplastic resin composition. Thereby, the function mentioned above can be provided to the 2nd release layer 2 reliably. Furthermore, the oxygen permeability of the release film 10 can be relatively easily set to the lower limit value or higher.

In addition, the polyester resin is not particularly limited, but for example, the same ones as those mentioned in the third thermoplastic resin composition can be used, and among them, polybutylene terephthalate (PBT) is particularly preferred. is preferred. Thereby, the effect obtained by using the polyester-based resin can be exhibited more remarkably. Furthermore, the oxygen permeability of the release film 10 can be more easily set to the above lower limit or more.

Furthermore, the polyester-based resin exhibits crystallinity, and the second release layer 2 made of this polyester-based resin is preferably suppressed in crystallization. is preferably about 10% or more and 50% or less, more preferably about 10% or more and 35% or less. As a result, the oxygen permeability of the release film 10 can be more easily set to the lower limit value or higher.

In addition, when the second thermoplastic resin composition is mainly composed of a polyester resin, it may contain a thermoplastic resin other than the polyester resin, and the thermoplastic resin is the first thermoplastic resin. The same ones as mentioned in the composition can be used.

Moreover, the second thermoplastic resin composition may further contain at least one of inorganic particles and organic particles in addition to the thermoplastic resin described above.

Although the inorganic particles and organic particles are not particularly limited, the same particles as those mentioned in the first thermoplastic resin composition can be used.

The second release layer 2 having such a structure preferably has a storage modulus E' at 150°C of 50 MPa or more, more preferably 50 MPa or more and 1000 MPa or less. Thereby, the function mentioned above can be provided to the 2nd release layer 2 reliably.

The average thickness T2 of the second release layer 2 is preferably set to 7 μm or more and 38 μm or less, and more preferably set to 10 μm or more and 30 μm or less. Thereby, the function mentioned above can be provided to the 2nd release layer 2 more reliably. In addition, the oxygen permeability of the release film 10 can be relatively easily set to the lower limit value or higher.

Furthermore, the second thermoplastic resin composition that constitutes the second release layer 2 contains the resin material, inorganic particles, and organic particles described above, as well as the same as those listed for the third thermoplastic resin composition. Additives may be included.

In addition, in the first release layer 1 and the second release layer 2, the first thermoplastic resin composition and the second thermoplastic resin composition may be the same or different, but substitutability are preferably the same or homogeneous from the viewpoint of having Furthermore, the average thickness of the first release layer 1 and the second release layer 2 may be the same or different.

In the release film 10 having the structure in which the first release layer 1, the cushion layer 3, and the second release layer 2 are laminated as described above, the average thickness Tt is 50 μm or more and 180 μm or less. It is preferably 80 μm or more and 150 μm or less, more preferably. As a result, the oxygen permeability of the release film 10 can be relatively easily set to the lower limit value or higher.

Here, the oxygen permeability of the release film 10 measured in accordance with JIS K 7126-2 may be 60.0 cc/(m ² ·atm · day) or more, but 100.0 cc/( m ² ·atm·day) or more, and more preferably 120.0 cc/(m ² ·atm·day) or more and 160.0 cc/(m ² ·atm·day) or less. By setting the oxygen permeability of the release film 10 as described above, the FPC 200 is removed in the second step from the second step until the release film 10 is released in the third step. Oxygen remaining between the release film 10 and the FPC 200 can permeate through the release film 10 during hot pressing. Therefore, even if the FPC 200 is heated when the FPC 200 is heated and pressed, it is possible to accurately suppress or prevent the circuits of the flexible circuit board 210 exposed in the recesses 223 from being oxidized.

In the present invention, the oxygen permeability of the release film 10 is determined according to the isobaric method of the plastic-film and sheet-gas permeability test method specified in JIS K 7126-2 at a temperature of 23 ° C. and a relative humidity of 0%. Measured under RH conditions.

In addition, the water vapor transmission rate of the release film 10 measured in accordance with JIS K 7129 (B method) is preferably more than 1.0 g/m ² ·day (25°C · 90% RH), It is more preferably 1.4 g/m ² ·day (25° C./90% RH) or more, and 1.7 g/m ² ·day (25° C./90% RH) or more and 3.0 g/m ² ·day ( 25° C./90% RH) or less is more preferable. By setting the water vapor permeability of the release film 10 as described above, the FPC 200 is removed in the second step from the second step until the release film 10 is released in the third step. Vapor contained in the air remaining between the release film 10 and the FPC 200 can permeate through the release film 10 during hot pressing. Therefore, when the FPC 200 is heat-pressed, the resin material such as polyimide contained as the constituent material of the flexible circuit board 210 and the coverlay 221 can accurately suppress or prevent moisture absorption while the FPC 200 is heated. obtain. Therefore, during soldering to the circuit provided on the flexible circuit board 210, the generation of air bubbles originating from moisture absorbed between the flexible circuit board 210 and the coverlay film 220 is accurately suppressed or prevented. Therefore, the resulting FPC 200 can be made more reliable by appropriately suppressing or preventing delamination between the flexible circuit board 210 and the coverlay film 220 .

In this embodiment, the release film 10 is composed of a laminate in which the first release layer 1, the cushion layer 3, and the second release layer 2 are laminated in this order. Not limited to the configuration, for example, an adhesive layer disposed between the first release layer 1 and the cushion layer 3 and/or between the second release layer 2 and the cushion layer 3 It may be composed of a laminate having an intermediate layer.

In addition, if the release film 10 can maintain excellent releasability between the glass cloth 300 and the release film 10 in the third step, the second release film 10 that contacts the glass cloth 300 Layer 2 may also be omitted.

<Method for producing release film 10>
The release film 10 configured as described above can be manufactured, for example, by the following manufacturing method. Before describing the method for manufacturing the release film 10, the release film manufacturing apparatus will be described first.

FIG. 6 is a side view schematically showing a release film manufacturing apparatus for manufacturing the release film 10 shown in FIG. In the following description, the upper side in FIG. 6 is called "upper", and the lower side is called "lower".

A release film manufacturing apparatus 1000 shown in FIG. 6 has a film supply section 600 and a film forming section 700 .

In this embodiment, the film supply section 600 is composed of an extruder 610 and a T-die 620 connected to the molten resin discharge section of the extruder 610 via a pipe. The T-die 620 supplies the belt-shaped film 10 ′ in a melted or softened state to the film forming section 700 .

The T-die 620 is an extrusion molding unit that extrudes the melted or softened film 10 ′ in the form of a belt-shaped film by a coextrusion method. The T-die 620 is sequentially charged with the material constituting each layer of the release film 10 described above in a molten state. ' is sent out continuously.

The film forming section 700 has a touch roll 710 , a cooling roll 720 and a post cooling roll 730 . These rolls are configured to rotate independently by motors (driving means) (not shown), respectively, and are cooled by the rotation of these rolls and fed out continuously. By continuously feeding the film 10′ in a melted or softened state into the film forming section 700, the surface of the film 10′ is flattened, and the film 10′ is set to a desired thickness and cooled. be. Then, by appropriately selecting the constituent materials of each layer constituting the release film 10 loaded in the extruder 610 (T die 620), the first release layer 1 and the cushion layer are formed as the cooled film 10'. 3 and the second release layer 2 are laminated in this order.

The release film 10 is manufactured by the method for manufacturing the release film 10 using the release film manufacturing apparatus 1000 as described above.

A method for manufacturing the release film 10 using the release film manufacturing apparatus 1000 includes an extrusion process, a molding process, and a cooling process.

<1A> First, a belt-shaped melted or softened film 10' is extruded (extrusion step).

In this extrusion process, the extruder 610 is sequentially loaded with constituent materials for each layer constituting the release film 10 . In addition, the constituent material of each layer constituting the release film 10 is in a melted or softened state inside the extruder 610 .

<2A> Next, the surface of the film 10' is flattened and the thickness of the film 10' is set to a predetermined thickness (forming step). This step is performed between the touch roll 710 and the cooling roll 720 .

<3A> Next, the surface of the film 10' is cooled (cooling step). This step is performed between the cooling roll 720 and the post cooling roll 730 .

The cooling temperature at which the surface of the film 10 ′ is cooled by the cooling roll 720 and the post-stage cooling roll 730 is preferably set to about 20° C. or higher and 120° C. or lower, more preferably about 40° C. or higher and 90° C. or lower. As a result, when the first release layer 1, the cushion layer 3, and the second release layer 2 each contain a resin material exhibiting crystallinity such as a polyester-based resin, the crystallization of the resin material can be accurately performed. It can be suppressed or prevented.

One of the cooling roll 720 and the post-cooling roll 730 may be provided with cooling means, and the film 10 ′ may be cooled by one of the rolls.

Regarding the steps <1A> to <3A> as described above, by appropriately selecting the constituent materials of each layer constituting the release film 10 loaded in the extruder 610, the first release layer 1 and the , the cushion layer 3 and the second release layer 2 are laminated in this order.

Although the method for producing the release film and the molded product of the present invention has been described above, the present invention is not limited to these.

For example, in the above-described embodiment, the case where the release film of the present invention is applied to a press molding method in which flexible printed circuit boards arranged between heating and cooling plates are laminated in one stage to manufacture was described. The number of laminated flexible printed circuit boards is not limited to one, and may be two or more.

In addition, the release film of the present invention is applied to the case where the flexible printed circuit board placed between the heating and cooling plates is pressed using a roll-to-roll press machine, but it is limited to this. Instead, the pressure applied to the flexible printed circuit board can be performed using, for example, a press molding method, or can be performed using a vacuum pressure molding method.

EXAMPLES The present invention will be described in detail below based on examples, but the present invention is not limited to these.

1. Preparation of raw materials As raw materials for manufacturing the release film, the following were prepared respectively.

・ Thermoplastic resin material Low-density polyethylene (LDPE, manufactured by Ube Maruzen Co., Ltd., "R300")
Ethylene vinyl acetate copolymer (EVA, Mitsui Dow Polychemicals, "P1403")
Polybutylene terephthalate (PBT, manufactured by Changchun Petrochemical Co., Ltd., "1100-630S")
Copolymerized polybutylene terephthalate (PBT, manufactured by Mitsubishi Engineering-Plastics, "5505S")
Polypropylene (PP, manufactured by Sumitomo Chemical Co., Ltd., "FH1016")
Glycol-modified polyethylene terephthalate (PETG, manufactured by SELENIS, "NF411")

2. Production of release film <Example 1>
First, as the first thermoplastic resin composition and the second thermoplastic resin composition, polybutylene terephthalate (PBT, 1100-630S) was prepared. Further, as the third thermoplastic resin composition, 15 parts by weight of polybutylene terephthalate (PBT, 1100-630S), 35 parts by weight of ethylene vinyl acetate copolymer (EVA, P1403), and low density polyethylene (LDPE, R300) 30 parts by weight and 20 parts by weight of polypropylene (PP, FH1016) were prepared.

Then, the first thermoplastic resin composition, the third thermoplastic resin composition and the second thermoplastic resin composition are co-extruded by a co-extrusion T-die method using the release film manufacturing apparatus 1000 to form a film. Thus, the release film 10 of Example 1 was obtained by forming a laminate in which the first release layer 1, the cushion layer 3, and the second release layer 2 were laminated in this order.

In addition, using the release film manufacturing apparatus 1000, the first thermoplastic resin composition, the third thermoplastic resin composition and the second thermoplastic resin composition are formed into films by the cooling roll 720 and the post cooling roll 730 The cooling temperature was set at 60°C.

In the obtained release film 10, the average thickness T1 of the first release layer 1 was 20 μm, the average thickness Tk of the cushion layer 3 was 80 μm, and the average thickness T2 of the second release layer 2 was 20 μm. there were.

Furthermore, the oxygen permeability of the release film 10 was measured using an oxygen permeability measuring device (manufactured by MOCON, "OX-TRAN 2/22L"), and the plastic-film specified in JIS K 7126-2 It was 100.0 cc/(m ² ·atm · day) when measured under conditions of a temperature of 23°C and a relative humidity of 0% RH according to the isobaric method of the sheet-gas permeability test method.

In addition, the water vapor transmission rate of the release film 10 was measured using a water vapor transmission rate measuring device (manufactured by MOCON, "PERMATRAN-W3/34") in accordance with K 7129 (B method) at a temperature of 25 ° C. , and a relative humidity of 90% RH, it was 2.5 g/m ² ·day (25°C, 90% RH).

Furthermore, the storage elastic modulus E′ at 150° C. of each of the first release layer 1 and the cushion layer 3 was measured using a dynamic viscoelasticity measuring device (manufactured by Hitachi High-Tech Science Co., Ltd., “DMA7100”) in tensile mode. , a frequency of 1 Hz, and a heating rate of 5° C./min, the results were 160 MPa and 16 MPa.

In addition, for the first release layer 1, the 10-point average roughness (Rz) on the surface exposed on the side opposite to the cushion layer 3 was measured using a surface roughness measuring device ("SURFTST SJ-210" manufactured by Mitutoyo Co., Ltd.). It was 5 μm when measured by

In addition, the crystallinity of each of the first release layer 1 and the second release layer 2 was measured using a sample horizontal X-ray diffractometer for thin film evaluation (manufactured by Rigaku, "Smart Lab"). Analysis by X-ray diffraction revealed 33% and 35%.

Calculation of the crystallinity of the first release layer 1 and the second release layer 2 based on the analysis by the wide-angle X-ray diffraction method was performed as follows. That is, after drawing a linear baseline in the range of 2θ = 12.0 ° to 28.18 ° on the diffraction measurement plot measured by a sample horizontal X-ray diffractometer for thin film evaluation, the crystalline phase and Fitting is performed on the amorphous phase as a Gaussian function, and based on the total peak area of the crystalline phase and the total peak area of the amorphous phase obtained by this, using the following formula A, the first The crystallinity of the release layer 1 and the second release layer 2 was calculated.
Crystallinity (%) =
Total peak area of crystalline phase/
(total peak area of crystalline phase + total peak area of amorphous phase) × 100 ... A

The measurement conditions in the sample horizontal X-ray diffractometer for thin film evaluation were set as follows.
X-ray source: CuKα ray, tube voltage: 45 kV-200 mA, incident optical system: focusing method, measurement range: 5-80°, measurement interval: 0.02°, scanning speed: 5.0°/min, scanning method: Out-of-Plane method

<Examples 2 to 4, Comparative Example 1>
Cooling temperature by the cooling roll 720 and the subsequent cooling roll 730 when filming the first thermoplastic resin composition, the third thermoplastic resin composition and the second thermoplastic resin composition using the release film manufacturing apparatus 1000 In the same manner as in Example 1, except that the was changed as shown in Table 1, Examples 2 to 4 in which the oxygen permeability of the release film 10 is as shown in Table 1, Comparative Example 1 A release film 10 was obtained.

<Examples 5 and 6, Comparative Example 2>
As the first thermoplastic resin composition, the second thermoplastic resin composition, and the third thermoplastic resin composition, those shown in Table 1 are used, and the average thickness is as shown in Table 1. Except that the release layer 1, the cushion layer 3, and the second release layer 2 were formed, the oxygen permeability in the thickness direction of the release film 10 was as shown in Table 1 in the same manner as in Example 1. The release films 10 of Examples 5 and 6 and Comparative Example 2 were obtained.

3. Evaluation The release films 10 of each example and each comparative example were evaluated as follows.

3-1. Discoloration due to circuit oxidation The release film 10 of each example and each comparative example was 270 mm wide, and a flexible circuit board 210 (Nippon Steel Chemical & Material Co., Ltd., "MB12-12-12REG ”), and a coverlay film 220 (“CMA0525” manufactured by Arisawa Seisakusho Co., Ltd.) is attached with the adhesive layer 222 of the coverlay film 220 facing the flexible circuit board 210, with a pitch of 50 μm, After making FPC 200 (laminate) having unevenness of 50 μm in width and 18 μm in height, release film 10 is applied to FPC 200 laminated as shown in FIG. -CURE 100TON CONTINUOUS LAMINATOR"), and pressed under the set conditions of 180° C., 110 kg/cm ² , and 150 sec. After that, as the release means 60, a configuration in which a bar is sandwiched between the FPC 200 and the release film 10 is applied, and the conveying speed is 200 mm/s, the feed rate is 500 mm, and the distance from the hot pressing plate 521 to the release means 60 is 50 mm. Then, the release film 10 was peeled off. Then, the degree of discoloration due to oxidation of the circuit exposed in the concave portion 223 of the FPC 200 was visually confirmed and evaluated according to the following criteria.

[Evaluation criteria]
A: No discoloration due to oxidation is observed in the circuit.
○: Although some discoloration due to oxidation is observed in the circuit,
It does not affect the electrical characteristics of the circuit.
×: Obvious discoloration due to oxidation is observed in the circuit,
It affects the electrical characteristics of the circuit.

3-2. Solder Resistance of Polyimide Substrate The release film 10 of each example and each comparative example was 270 mm wide, and a coverlay film 220 (manufactured by Arisawa Seisakusho Co., Ltd., "CMA0525") was applied to the flexible circuit board 210. , FPC 200 (laminate) having unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm, which is formed by attaching the adhesive layer 222 of the coverlay film 220 to the flexible circuit board 210 side, The release film 10 is applied to the laminated FPC 200 as shown in FIG ^. It was pushed in under the setting condition of 150 sec. After that, as the release means 60, a configuration in which a bar is sandwiched between the FPC 200 and the release film 10 is applied, and the conveying speed is 200 mm/s, the feed rate is 500 mm, and the distance from the hot pressing plate 521 to the release means 60 is 50 mm. Then, the release film 10 was peeled off.

Then, according to JPCA standard JPCA-DG04, FPC200 pressed using an RtoR press was dried at 110° C. for 1 hour. After that, the FPC 200 was immersed in a solder liquid heated to 260° C. for 10 seconds, and then taken out from the solder liquid. Then, the presence or absence of air bubbles generated between the flexible circuit board 210 and the coverlay film 220 was visually confirmed and evaluated according to the following criteria. For the release films 10 of each example and each comparative example, the test for obtaining FPC 200 was repeated 100 times as described above.

[Evaluation criteria]
A: No air bubbles are generated between the flexible circuit board 210 and the coverlay film 220 .
○: The probability of air bubbles being generated between the flexible circuit board 210 and the coverlay film 220 is less than 1%.
x: The probability that air bubbles are generated between the flexible circuit board 210 and the coverlay film 220 is 1% or more.

3-3. Embedability of release film The release film 10 of each example and each comparative example was 270 mm wide, and a cover lay film 220 (manufactured by Arisawa Seisakusho Co., Ltd., "CMA0525") was placed on the flexible circuit board 210. The FPC 200 (laminate) having unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm, which is formed by attaching the adhesive layer 222 of the cover lay film 220 to the flexible circuit board 210 side. , the release film 10 is applied to the laminated FPC 200 as shown in FIG ^. , was pushed under the setting condition of 150 sec. After that, in a state in which the FPC 200 and the release film 10 were laminated, the laminate was cut in the thickness direction, and then one end of the release film 10 was held and the release film 10 was peeled off. When one end of the release film 10 was gripped and peeled off, the maximum amount of the adhesive seeping out in the concave portion of the FPC 200 in plan view was measured and evaluated according to the following criteria.

[Evaluation criteria]
A: The maximum seepage amount is less than 55 mm.
Good: The maximum seepage amount is 55 or more and less than 65 mm.
x: The maximum seepage amount is 65 mm or more.

3-4. Releasability of release film The release film 10 of each example and each comparative example was 270 mm wide, and a coverlay film 220 (manufactured by Arisawa Seisakusho Co., Ltd., "CMA0525") was applied to the flexible circuit board 210. ) was formed by attaching the adhesive layer 222 of the cover lay film 220 to the flexible circuit board 210 side, and the FPC 200 (laminated body) provided with unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Later, the release film 10 is applied to the laminated FPC 200 as shown in FIG. ² , pressed under the setting condition of 150 sec. After that, as the release means 60, a configuration in which a bar is sandwiched between the FPC 200 and the release film 10 is applied, and the conveying speed is 200 mm/s, the feed rate is 500 mm, and the distance from the hot pressing plate 521 to the release means 60 is 50 mm. Then, the release film 10 was peeled off. At that time, the ease of peeling off the release film 10 (releasability) was evaluated according to the following criteria.

[Evaluation criteria]
Good: Peelable when the release film is peeled off.
x: When the release film is peeled off, the cushion layers are fused to each other and the separation is difficult.

3-5. Conclusion 3-1. Discoloration due to circuit oxidation, 3-2. Solder resistance of polyimide substrate, 3-3. Embedability of release film, and 3-4. Table 1 shows the evaluation results obtained in the releasability of the release film.

As shown in Table 1, each example satisfied that the release film 10 had an oxygen permeability of 60.0 cc/(m ² ·atm · day) or more. The results showed that discoloration due to oxidation was suppressed in circuits exposed to .

On the other hand, in each comparative example, it is not satisfied that the release film 10 has an oxygen permeability of 60.0 cc/(m ² ·atm · day) or more. The result showed that discoloration due to oxidation was clearly observed in the circuit exposed in the recess 223 .

1 first release layer 2 second release layer 3 cushion layer 10 release film 10A release film 10B release film 10' film 50 heat press means 52 heat press unit 60 release means 100 roll-to-roll press machine 200 flexible Printed circuit board (FPC)
210 flexible circuit board 220 coverlay film (CL film)
221 Coverlay 222 Adhesive layer 223 Concave portion 300A Glass cloth 300B Glass cloth 521 Thermocompression plate 600 Film supply section 610 Extruder 620 T die 700 Film forming section 710 Touch roll 720 Cool roll 730 Post cooling roll 1000 Release film manufacturing apparatus T1 Average thickness of first release layer T2 Average thickness of second release layer Tk Average thickness of cushion layer Tt Average thickness of release film

Claims (10)

Having a first release layer made of a first thermoplastic resin composition and a cushion layer laminated on the first release layer,
On the surface of an object formed of a material containing a thermosetting resin in a semi-cured state, placed on a metal substrate,
A release film that is used so that the surface on the first release layer side is in contact ,
The oxygen permeability of the release film, measured in accordance with JIS K 7126-2, is 100.0 cc/(m ² atm day) or more and 160.0 cc/(m ² atm day) or less. A release film characterized by the following. The release film according to claim 1, wherein the first thermoplastic resin composition contains a polyester-based resin. The release film according to claim 2, wherein the polyester resin has crystallinity, and the crystallinity of the first release layer is 10% or more and 50% or less. 4. The release film according to claim 3, wherein the cushion layer is made of a third thermoplastic resin composition containing the polyester resin and the polyolefin resin. The release film according to claim 1 or 4, wherein the first release layer has an average thickness of 7 µm or more and 38 µm or less. The release film according to claim 5, wherein the cushion layer has an average thickness of 40 µm or more and 110 µm or less. The release film according to claim 6, wherein the release film has an average thickness of 50 µm or more and 180 µm or less. The release film according to claim 1, wherein the first release layer has a 10-point average roughness (Rz) of 0.1 µm or more and 20.0 µm or less on the surface opposite to the cushion layer. 2. The release film according to claim 1, further comprising a second release layer made of a second thermoplastic resin composition and laminated on the side opposite to the first release layer of the cushion layer. So that the first release layer of the release film according to claim 1 is on the object side,
The step of placing the release film on the object, and the step of subjecting the object on which the release film is placed to a hot press, wherein the step of placing the release film includes: A method for manufacturing a molded product, wherein the surface of the object on which the release film is arranged is made of a material containing a semi-cured thermosetting resin.

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