Release film and method for producing molded article

Abstract

A mold release film (10) according to the first invention has a first mold release layer (1) comprising a first thermoplastic resin composition and a buffer layer (3) laminated on the first mold release layer (1), and satisfies the oxygen transmission rate of the mold release film (10) as measured in accordance with JIS K 7126-2 of 60.0 cc / (m2. Atm. Day) or more. A mold release film (10) according to the second invention has a first mold release layer (1) comprising a first thermoplastic resin composition and a buffer layer (3) laminated on the first mold release layer (1), and the water vapor transmission rate of the mold release film (10) as measured in accordance with JIS K 7129 (method B) exceeds 1.0 g / m2 * day (25 DEG C * 90% RH).

Description

Technical Field

[0001] The present invention relates to a release film and a method for manufacturing a molded article. Background Art

[0002] When forming a flexible printed circuit board, i.e., a laminate, by thermocompression bonding a cover film to a flexible circuit board with exposed circuits via an adhesive layer provided in the cover film, a release film is usually used.

[0003] When forming a flexible printed circuit board using such a release film, in other words, a laminate of a flexible circuit board and a cover film, the release film is required to have two excellent properties: embeddability and releasability.

[0004] Specifically, first, when a cover film is laminated on a flexible circuit board to form a recess in the flexible printed circuit board, the release film is required to exhibit excellent embeddability with respect to the recess.

[0005] More specifically, the lamination of the cover film on the flexible circuit board is performed via the adhesive layer provided in the cover film. When performing this lamination, the release film is required to exhibit excellent embeddability with respect to the recess to suppress the seepage of the adhesive into the recess.

[0006] Furthermore, after laminating the cover 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.

[0007] More specifically, when peeling the release film from the formed flexible printed circuit board, the release film is required to exhibit excellent releasability with respect to the flexible printed circuit board to suppress the occurrence of creases and breaks in the flexible printed circuit board.

[0008] In order to produce a release film having the above-described two excellent properties (embeddability and releasability), for example, Patent Document 1 proposes a release film having a polyester-based elastomer layer and a polyester layer.

[0009] However, when considering manufacturing the flexible printed circuit board to have more excellent electrical properties, the following problems exist. More specifically, when manufacturing a flexible printed circuit board using a release film having such a structure, when the cover film is thermocompression bonded to the flexible circuit board, the circuits provided in the flexible circuit board are oxidized by 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 more excellent electrical properties can actually be obtained.

[0010] Moreover, the same problem also occurs in the following cases: a release film is attached to an object formed of a material containing a semi-cured thermosetting resin disposed on a metal substrate, and in this state, the thermosetting resin is caused to undergo a curing reaction, thereby manufacturing a molded article using the object.

[0011] In contrast to the above problems, when manufacturing a flexible printed circuit board having excellent bonding characteristics for soldering the circuit provided on the flexible circuit board, when manufacturing the flexible printed circuit board using the release film having this structure, the following problems actually occur. That is, when the cover film is thermocompression bonded to the flexible circuit board, resin materials such as polyimide contained as constituent materials of the flexible printed circuit board absorb water vapor contained in the air remaining between the release film and the flexible printed circuit board. As a result, when soldering the circuit provided on the flexible circuit board, the absorbed water vapor forms bubbles between the cover film and the flexible circuit board, and thus there is a problem of peeling between the cover film and the flexible circuit board.

[0012] Moreover, the same problem also occurs in the following cases: a state in which a release film is attached to an object formed of a material containing a thermosetting resin in a semi-cured state and disposed on a metal substrate, and in this state, the thermosetting resin is caused to undergo a curing reaction, thereby manufacturing a molded product using the object, and then soldering the metal substrate provided on the molded product.

[0013] Prior Art Documents

[0014] Patent Documents

[0015] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-88351. Summary of the Invention

[0016] Problems to be Solved by the Invention

[0017] A first object of the present invention is to provide a release film and a method for manufacturing a molded product using the release film, which can surely suppress or prevent oxidation of a metal substrate exposed in a concave portion during the period from filling the concave portion with the release film to demolding the release film from the concave portion.

[0018] A second object of the present invention is to provide a release film and a method for manufacturing a molded product using the release film, which can surely suppress or prevent a resin material contained as a constituent material of the molded product from absorbing water vapor during the period from filling a concave portion provided in the molded product with the release film to demolding the release film from the concave portion.

[0019] Technical Solutions for Solving the Problems

[0020] This object is achieved by the present invention described in the following (1) to (12). In particular, the first object is achieved by the present invention (the first invention) described in the following (1). And the second object is achieved by the present invention (the second invention) described in the following (2). In addition, in the following description, the first invention and the second invention are sometimes collectively referred to as the present invention.

[0021] (1) A release film having a first release layer composed of a first thermoplastic resin composition and a buffer layer laminated on the first release layer, wherein the release film is characterized in that

[0022] The oxygen permeability of the release film measured in accordance with JIS K 7126-2 is 60.0 cc / (m 2 ·atm·day) or more.

[0023] (2) A release film having a first release layer composed of a first thermoplastic resin composition and a buffer layer laminated on the first release layer, wherein the release film is characterized in that

[0024] The water vapor permeability of the release film measured in accordance with JIS K 7129 (Method B) exceeds 1.0 g / m 2 ·day (25 °C · 90% RH).

[0025] (3) The release film according to the above (1) or (2), wherein

[0026] The first thermoplastic resin composition contains a polyester resin.

[0027] (4) The release film according to any one of the above (1) to (3), wherein

[0028] The polyester resin has crystallinity, and the crystallinity of the first release layer is 10% or more and 50% or less.

[0029] (5) The release film according to any one of the above (1) to (4), wherein

[0030] The buffer layer is composed of a third thermoplastic resin composition containing the polyester resin and a polyolefin resin.

[0031] (6) The release film according to any one of the above (1) to (5), wherein

[0032] The average thickness of the first release layer is 7 μm or more and 38 μm or less.

[0033] (7) The release film according to any one of the above (1) to (6), wherein

[0034] The average thickness of the buffer layer is 40 μm or more and 110 μm or less.

[0035] (8) The release film according to any one of the above (1) to (7), wherein

[0036] The average thickness of the release film is 40 μm or more and 180 μm or less.

[0037] (9) The release film according to any one of (1) to (8) above, wherein,

[0038] in the first release layer, the ten-point average roughness (Rz) of the surface on the side opposite to the buffer layer is 0.1 μm or more and 20.0 μm or less.

[0039] (10) The release film according to any one of (1) to (9) above, wherein,

[0040] the release film has a second release layer made of a second thermoplastic resin composition laminated on the side of the buffer layer opposite to the first release layer.

[0041] (11) The release film according to any one of (1) to (10) above, wherein,

[0042] the release film is used in an overlapping manner such that the surface on the first release layer side is in contact with the surface of an object formed of a material containing a thermosetting resin in a semi-cured state disposed on a metal substrate.

[0043] (12) A method for manufacturing a molded article, characterized by comprising: a step of disposing the release film according to any one of (1) to (11) above on the object such that the first release layer of the release film faces the object side; and a step of thermocompression-bonding the object on which the release film is disposed. In the step of disposing the release film, the surface of the object on the side where the release film is disposed is formed of a material containing a thermosetting resin in a semi-cured state.

[0044] Advantages of the Invention

[0045] According to the first invention, in a release film having a first release layer made of a first thermoplastic resin composition and a buffer layer laminated on the first release layer, the oxygen transmission rate of the release film measured in accordance with JIS K 7126-2 satisfies 60.0 cc / (m 2 ·atm·day) or more. Therefore, for example, when using a flexible circuit board and a cover film to obtain a flexible printed circuit board, during the period from filling the recess with the release film to releasing the release film from the recess, oxidation of the circuit provided on the flexible circuit board exposed in the recess can be surely suppressed or prevented. Therefore, a flexible printed circuit board having more excellent electrical characteristics can be obtained.

[0046] And, according to the second invention, in a release film having a first release layer made of a first thermoplastic resin composition and a buffer layer laminated on the first release layer, the water vapor transmission rate of the release film measured in accordance with JIS K 7129 (Method B) exceeds 1.0 g / m 2·Day (25°C · 90% RH). Therefore, for example, when using a flexible circuit board and a cover film to obtain a flexible printed circuit board, during the period from filling the recess with the release film to releasing the release film from the recess, it is possible to surely suppress or prevent a resin material such as polyimide included as a constituent material of the flexible printed circuit board from absorbing water vapor contained in the air remaining between the release film and the flexible circuit board. Therefore, it is possible to surely suppress or prevent the generation of bubbles derived from the absorbed water vapor between the cover film and the flexible circuit board when soldering the circuit provided on the flexible circuit board. Therefore, a flexible printed circuit board with more excellent reliability that surely suppresses or prevents peeling between the cover film and the flexible circuit board can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a side view showing the main part of a roll-to-roll press for manufacturing a flexible printed circuit board.

[0048] Figure 2 is showing the use of Figure 1 is a longitudinal sectional view showing each process in a method for manufacturing a flexible printed circuit board using the roll-to-roll press shown.

[0049] Figure 3 is showing the use of Figure 1 is a longitudinal sectional view showing a hot pressing process in a method for manufacturing a flexible printed circuit board using the roll-to-roll press shown.

[0050] Figure 4 is a longitudinal sectional view showing an embodiment of the release film of the present invention.

[0051] Figure 5 is a partial enlarged Figure 4 is a partial enlarged longitudinal sectional view obtained by enlarging part A of the release film shown.

[0052] Figure 6 is schematically showing the manufacturing Figure 4 is a side view of a release film manufacturing apparatus for manufacturing the release film shown. DETAILED DESCRIPTION OF THE INVENTION

[0053] Hereinafter, based on the preferred embodiments shown in the drawings, the method for manufacturing the release film and the molded product of the present invention will be described in detail.

[0054] In addition, hereinafter, the case of manufacturing a flexible printed circuit board using the release film of the present invention using a roll-to-roll press will be described as an example. And, before describing the method for manufacturing the release film and the molded product of the present invention, first, the roll-to-roll press for manufacturing the flexible printed circuit board will be described.

[0055] <Roll-to-Roll Press>

[0056] Figure 1 is a side view showing the main part of a roll-to-roll press for manufacturing a flexible printed circuit board, Figure 2 is showing the use of Figure 1 a longitudinal sectional view of each process in a method for manufacturing a flexible printed circuit board using the roll-to-roll press shown, Figure 3 is showing the use of Figure 1 a longitudinal sectional view of the hot pressing process in a method for manufacturing a flexible printed circuit board using the roll-to-roll press shown. In addition, hereinafter, for ease of explanation, the upper side in Figures 1 to 3 is referred to as "upper" or "above", the lower side is referred to as "lower" or "below", the left side is referred to as "left", and the right side is referred to as "right".

[0057] The roll-to-roll press 100 (RtoR press) includes: a conveying mechanism (not shown) that conveys a release film 10, a flexible printed circuit board 200 (hereinafter, also referred to as "FPC"), and glass cloths 300A and 300B; a hot pressing mechanism 50 that uses the release film 10 to bond a CL film 220 to a flexible circuit board 210 in the FPC 200 by hot pressing; and a demolding mechanism 60 that demolds (peels) the release film 10 from the FPC 200 in which the CL film 220 is bonded to the flexible circuit board 210.

[0058] The conveying mechanism is configured to convey the FPC 200, the release films 10A and 10B, and the glass cloths 300A and 300B respectively wound around different unwinding rollers along their long side directions by the rotation of tension rollers, and to wind them onto a winding roller after being processed by the hot pressing mechanism 50 and the demolding mechanism 60.

[0059] In addition, each roller is made of a metal material such as stainless steel, for example. And the rotation axes (central axes) of these rollers are oriented in the same direction and are arranged at intervals from each other.

[0060] As Figure 1 shown, the hot pressing mechanism 50 has a heated crimping portion 52.

[0061] The thermocompression bonding part 52 has a pair of thermocompression bonding plates 521. The thermocompression bonding plates 521 face the glass cloth 300A, the release film 10A, the FPC 200, the release film 10B, and the glass cloth 300B that are conveyed by the conveying mechanism and in a superposed state, and one is arranged above and below respectively. And when the superposed glass cloth 300A, release film 10A, FPC 200, release film 10B, and glass cloth 300B pass between the thermocompression bonding plates 521, the FPC 200 is heated and pressed through the thermocompression bonding plates 521 via the glass cloth 300A, glass cloth 300B, and release film 10A, release film 10B. Therefore, the curing reaction of the adhesive layer 222 included in the CL film 220 proceeds through this heating. Thus, in the FPC 200, the superposed flexible circuit board 210 and the CL film 220 are joined via the adhesive layer 222.

[0062] In other words, the cover layer 221 and the flexible circuit board 210 are joined via the adhesive layer 222. And when the FPC 200 is heated / pressed, that is, when the cover layer 221 and the flexible circuit board 210 are joined via the adhesive layer 222, the release film 10 is buried in the recess 223 formed in the cover layer 221. Therefore, it is possible to suppress the adhesive from the adhesive layer 222 from oozing out in the recess 223 (refer to Figure 2 (b)).

[0063] In addition, before the thermocompression bonding is performed by the thermocompression bonding plates 521, the FPC 200 is in a state of being laminated by superposing the flexible circuit board 210 and the CL film 220, but the flexible circuit board 210 and the CL film 220 are not joined via the adhesive layer 222 included in the CL film 220. Then, through the pressing by the thermocompression bonding plates 521, the adhesive layer 222 included in the CL film 220 is closely attached to the flexible circuit board 210. Furthermore, in this state, the curing reaction of the adhesive layer 222 proceeds through the heating by the thermocompression bonding plates 521, whereby the flexible circuit board 210 and the CL film 220 are joined via the adhesive layer 222.

[0064] As Figure 1 shown, the demolding mechanism 60 is arranged on the downstream side in the conveying direction with respect to the hot pressing mechanism 50. The demolding mechanism 60 is configured to separate the FPC 200 from the release film 10A and the release film 10B. Here, in the thermocompression bonding part 52 of the hot pressing mechanism 50, the release film 10 is buried in the recess 223 formed in the cover layer 221. Thus, the CL film 220 (FPC 200) is joined to the release film 10, but it is configured to be able to peel (demold) the release film 10 from the CL film 220 (FPC 200) by the action of this demolding mechanism 60 (refer to Figure 2(c)). Therefore, based on the action of the demolding mechanism 60, the FPC 200 having a structure in which the flexible circuit board 210 and the CL film 220 are joined via the adhesive layer 222 can be obtained in a state of being peeled off from the demolding film 10.

[0065] Using the roll-to-roll press 100 as described above, a flexible printed circuit board 200 (FPC 200) can be manufactured. Hereinafter, a method for manufacturing the FPC 200 using this roll-to-roll press will be described. In addition, the manufacturing method of the molded product of the present invention is applied to the manufacturing method of the FPC 200.

[0066] In the present embodiment, the manufacturing method of the FPC 200 includes: a first step of producing a laminate in a state where the glass cloth 300A, the demolding film 10A, the FPC 200, the demolding film 10B, and the glass cloth 300B, each in a sheet form, are sequentially overlapped; a second step of joining the cover layer 221 (CL film 220) and the flexible circuit board 210 via the adhesive layer 222 in the FPC 200 by thermocompression of the laminate; and a third step of demolding the demolding film 10 (10A, 10B) from the FPC 200 to obtain the FPC 200 with the CL film 220 joined to the flexible circuit board 210.

[0067] Hereinafter, each of these steps will be described in sequence.

[0068] (First step)

[0069] First, when the glass cloth 300A, the demolding film 10A, the FPC 200, the demolding film 10B, and the glass cloth 300B, each in a sheet form and wound around a pay-off roll, are conveyed by a conveying mechanism, they are set as a laminate in a state of being overlapped in this order (refer to the demolding film arrangement step, Figure 1 , Figure 2 (a), Figure 3 .).

[0070] In addition, the method of laminating each component (film) into a laminate is not particularly limited. For example, they can be laminated while being pressed by a roller, or can be laminated while being pressed by a press. And the order of laminating each component can be set arbitrarily. For example, all components can be laminated simultaneously, or the cover film 220 and the flexible circuit board 210 can be laminated in advance, and then other components can be laminated simultaneously.

[0071] And, by forming the laminate in the first step, the step of arranging the demolding film 10 on the object (FPC 200) in the manufacturing method of the molded product of the present invention is constituted.

[0072] (Second step)

[0073] Next, using the hot pressing mechanism 50 (heating and pressing portion 52), while pressing the laminate in which the glass cloth 300A, the release film 10A, the FPC 200, the release film 10B, and the glass cloth 300B are sequentially stacked, heating (hot pressing) is performed. Thus, the curing reaction of the adhesive layer 222 proceeds in a state where the adhesive layer 222 is in close contact with the flexible circuit board 210 (the adhesive layer 222 is cured). Therefore, in the FPC 200, a bonded body in which the cover layer 221 (CL film 220) and the flexible circuit board 210 are joined via the adhesive layer 222 is formed (refer to the hot pressing process, Figure 1 , Figure 2 (b), Figure 3 .).

[0074] Moreover, at this time, while the release film 10A is in close contact with the cover layer 221, the release film 10A is buried in the concave portion 223 formed in the cover layer 221, thereby suppressing the adhesive from the adhesive layer 222 from oozing out in the concave portion 223.

[0075] In addition, for example, when the FPC 200 is applied to in-vehicle use, the height of the step difference of the concave portion 223 formed in the FPC 200 (cover layer 221) is set to a size of about 30 μm or more and 100 μm or less.

[0076] In this second process (hot pressing process), the temperature for heating the FPC 200 is not particularly limited. For example, it is preferably 100°C or more and 250°C or less, and more preferably 150°C or more and 200°C or less.

[0077] Moreover, in the second process, when pressing the FPC 200, the pressure set in the heating and pressing portion 52 is not particularly limited, and is preferably set to 1 MPa or more and 14 MPa or less, and more preferably set to 5 MPa or more and 14 MPa or less.

[0078] In addition, the conveying speed of the laminate is preferably set to 40 mm / sec or more and 400 mm / sec or less, and more preferably set to 100 mm / sec or more and 350 mm / sec or less. In other words, in the second process (this process), the laminate is hot pressed using the hot pressing mechanism 50. In the peeling process (the next process), the close contact time for peeling the release film 10 from the bonded body is preferably set to 1.0 sec or more and 10.0 sec or less, and more preferably set to 4.0 sec or more and 7.0 sec or less. It can be said that by setting the conveying speed, that is, the close contact time, within this range, the FPC 200 can be manufactured efficiently. That is, it can be said that the FPC 200 is manufactured with excellent productivity.

[0079] In addition, this is a step of thermocompression bonding on an object (FPC 200) provided with a release film 10 in the method for manufacturing a molded product according to the second step of the present invention. When the cover layer 221 (insulating layer) is made of a material containing a thermosetting resin in a semi-cured state, the cover layer 221 constitutes the surface on the side of the object (FPC 200) where the release film 10 is provided. Since the release film 10 is overlapped so that the surface on the first release layer 1 side contacts the surface of the cover layer 221, the shape of the cover layer 221 having the recess 223 formed therein can be maintained by the release film 10 to cure the thermosetting resin. Therefore, the cover layer 221 (molded product) can be formed on the flexible printed circuit board 210 with excellent precision. And since the adhesion time is set within the above range, the curing reaction of the thermosetting resin constituting the cover layer 221 can be performed while maintaining the shape of the cover layer 221 having the recess 223 formed therein by the release film 10.

[0080] In addition, in the present embodiment, a heating means by thermocompression bonding is shown, but the method is not limited thereto. For example, heating can be performed by infrared rays or a heating roller.

[0081] During the period from this second step (thermocompression bonding step) to the release of the release film 10 from the FPC 200 in the next third step (release step), the release film 10 is attached to the FPC 200. At this time, in the first invention, the oxygen transmission rate of the release film 10 measured according to JIS K7126-2 satisfies 60.0 cc / (m 2 ·atm·day) or more. Therefore, during the period from the second step (this step) to the release of the release film 10 in the third step (next step), as described above, in the second step (this step), even when the FPC 200 is thermocompression bonded, it is possible to surely suppress or prevent the circuit provided on the flexible printed circuit board 210 exposed in the recess 223 from being oxidized. Therefore, an FPC 200 having more excellent electrical characteristics can be obtained, and the details will be described later.

[0082] During the period from this second step (thermocompression bonding step) to the release of the release film 10 from the FPC 200 in the next third step (release step), when the release film 10 is attached to the FPC 200, in the second invention, the water vapor transmission rate of the release film 10 measured according to JIS K 7129 (Method B) exceeds 1.0 g / m 2·Day (25°C · 90% RH). Therefore, during the period from the second process (this process) to the third process (the next process) until the release film 10 is released, as described above, in the second process (this process), even if the FPC 200 is hot-pressed, it is still possible to surely suppress or prevent resin materials such as polyimide contained in the constituent materials of the flexible circuit board 210 and the cover layer 221 from absorbing the water vapor contained in the air remaining between the release film 10 and the flexible circuit board 210. Therefore, it is possible to surely suppress or prevent the generation of bubbles originating from the absorbed water vapor between the flexible circuit board 210 and the cover film 220 when welding the circuit provided on the flexible circuit board 210. Therefore, an FPC 200 with more excellent reliability that surely suppresses or prevents peeling between the flexible circuit board 210 and the cover film 220 can be obtained, and its detailed content will be described later.

[0083] (The third process)

[0084] Next, in the release mechanism 60, the release film 10 (10A, 10B) is released from the FPC 200. That is, the release film 10A and the release film 10B are peeled off from the bonded body of the cover film 220 and the flexible circuit board 210. Thereby, an FPC 200 in which the CL film 220 is bonded to the flexible circuit board 210 is obtained (refer to the peeling process, Figure 1 , Figure 2 (c), Figure 3 .).

[0085] In addition, the release mechanism 60 is not particularly limited. For example, it may be a structure in which vacuum is drawn by providing a vacuum device on the outside for peeling, or a structure in which air is introduced between the bonded body and the release film 10A, 10B for peeling, or a structure in which a rod is sandwiched between the bonded body and the release film 10A, 10B for peeling.

[0086] After that, the bonded body of the cover 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 respectively wound up on the winding rollers.

[0087] Through this winding, an 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 is continuously obtained in a state wound up on the winding rollers.

[0088] As described above, by applying the manufacturing method of the flexible printed circuit board 200 using the roll-to-roll press 100 using the release film 10, the flexible printed circuit board 200 is continuously manufactured.

[0089] In addition, after the above-described third step, the following step may be included: the flexible printed circuit board 200 wound to a take-up roller or the wound flexible printed circuit board 200 is cut into sheets in their respective states, and heated using an oven or the like, thereby further performing a curing reaction of the thermosetting resin constituting the cover layer 221 to cure the cover layer 221.

[0090] The release film 10 used for manufacturing the flexible printed circuit board 200 is the release film of the present invention. Hereinafter, the release film 10 to which the release film of the present invention is applied will be described.

[0091] <Release film 10>

[0092] Figure 4 is a longitudinal sectional view showing an embodiment of the release film of the present invention, Figure 5 is a partial enlargement Figure 4 of part A of the shown release film, which is a longitudinally enlarged sectional view.

[0093] As Figure 4 shown, in the present embodiment, the release film 10 is composed of a laminate in which a first release layer 1, a buffer layer 3, and a second release layer 2 are laminated in sequence, and is overlapped and used such that the surface on the first release layer 1 side is in contact with the CL film 220 included in the FPC 200.

[0094] Moreover, in the first invention, for this release film 10, the oxygen transmission rate of the release film 10 measured in accordance with JIS K 7126-2 is 60.0 cc / (m 2 ·atm·day) or more.

[0095] Here, as described above, in the method for manufacturing the flexible printed circuit board 200 using the release film 10, it is required to balance the filling property of the release film 10 for the concave portion 223 and the releasability from the flexible printed circuit board 200. In addition, it is required to manufacture the FPC 200 having more excellent electrical characteristics.

[0096] However, during the period until the release film 10 is released from the second step (this step) to the third step (the next step), as described above, in the second step (this step), when the FPC 200 is hot-pressed, the circuit included in the flexible circuit board 210 is oxidized by oxygen contained in the air remaining between the release film 10 and the FPC 200. Therefore, there is a problem that the FPC 200 having more excellent electrical characteristics cannot be obtained.

[0097] Regarding this problem, in the first invention, as the release film 10, as described above, the release film 10 having an oxygen transmission rate measured in accordance with JIS K7126-2 of 60.0 cc / (m 2·atm·days) or more. That is, as the release film 10, a structure with excellent oxygen permeability in the thickness direction is selected. Therefore, during the period from the second process (this process) to the third process (the next process) until the release film 10 is released, as described above, in the second process (this process), when hot-pressing the FPC 200, oxygen can permeate through the release film 10 and remain between the release film 10 and the FPC 200. Therefore, when hot-pressing the FPC 200, even if the FPC 200 is heated, it is possible to surely suppress or prevent the circuit provided on the flexible circuit board 210 exposed in the recess 223 from being oxidized. Therefore, an FPC 200 with more excellent electrical characteristics can be obtained.

[0098] Moreover, regarding the release film 10, in the second invention, the water vapor transmission rate of the release film measured according to JIS K 7129 (Method B) exceeds 1.0 g / m 2 ·day (25 °C · 90% RH).

[0099] Here, as described above, in the manufacturing method of the flexible printed circuit board 200 using the release film 10, it is required to balance the landfillability of the release film 10 to the recess 223 and the releasability from the flexible printed circuit board 200. In addition, it is also required to manufacture an FPC 200 with excellent bonding characteristics for welding the circuit provided on the flexible circuit board 210.

[0100] However, during the period from the second process (this process) to the third process (the next process) until the release film 10 is released, as described above, in the second process (this process), when hot-pressing the FPC 200, resin materials such as polyimide included in the constituent materials of the flexible circuit board 210 and the cover layer 221 absorb the water vapor contained in the air remaining between the release film 10 and the FPC 200. As a result, when welding the circuit provided on the flexible circuit board 210, the absorbed water vapor generates bubbles between the flexible circuit board 210 and the cover film 220. Therefore, there is a problem that these bubbles cause peeling between the flexible circuit board 210 and the cover film 220.

[0101] To address this problem, in the second invention, as the release film 10, as described above, the water vapor transmission rate of the release film measured according to JIS K7129 (Method B) is selected to exceed 1.0 g / m 2· Structure under the condition of 1 day (25°C, 90% RH). That is, as the release film 10, a structure with excellent water vapor transmission rate in the thickness direction is selected. Therefore, during the period from the second process (this process) to the third process (the next process) until the release film 10 is demolded, as described above, in the second process (this process), when hot-pressing the FPC 200, the water vapor contained in the air remaining between the release film 10 and the FPC 200 can pass through the release film 10. Therefore, when hot-pressing the FPC 200 and heating the FPC 200, it is possible to surely suppress or prevent resin materials such as polyimide included in the constituent materials of the flexible circuit board 210 and the cover layer 221 from absorbing water vapor. Therefore, it is possible to surely suppress or prevent the generation of bubbles caused by the absorbed water vapor between the flexible circuit board 210 and the cover film 220 when welding the circuit provided on the flexible circuit board 210. Therefore, an FPC 200 with more excellent reliability in surely suppressing or preventing peeling between the flexible circuit board 210 and the cover film 220 can be obtained.

[0102] Hereinafter, each layer constituting the release film 10 will be described.

[0103] <Buffer layer 3>

[0104] First, the buffer layer 3 will be described. The buffer layer 3 is arranged as an intermediate layer between the first release layer 1 and the second release layer 2.

[0105] The buffer layer 3 is composed of a third thermoplastic resin composition, for the purpose of endowing the release film 10 with the property of filling the recess 223 and setting the oxygen transmission rate of the release film 10 to be equal to or higher than the lower limit value or setting the water vapor transmission rate of the release film 10 to exceed the lower limit value. In the present invention, the third thermoplastic resin composition preferably uses a structure containing a plurality of thermoplastic resins.

[0106] As combinations of a plurality of thermoplastic resins, for example, combinations of polyester-based resins and polyolefin-based resins, combinations of polyolefin-based resins with each other, and combinations of polyamide-based resins and polyolefin-based resins can be cited. Among them, by selecting the combination of polyester-based resins and polyolefin-based resins, it is possible to relatively easily set the oxygen transmission rate of the release film 10 to be equal to or higher than the lower limit value. And by selecting the combination of polyester-based resins and polyolefin-based resins, it is possible to relatively easily set the water vapor transmission rate of the release film 10 to exceed the lower limit value.

[0107] As the polyester resin, there is no particular limitation. For example, polyethylene terephthalate (PET), polycyclohexanedimethylene terephthalate (PCT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycyclohexylene dimethylene terephthalate, polypropylene terephthalate, etc. can be cited. One of them can be used or two or more of them can be used in combination. In addition, when two or more of them are used in combination, the polyester resin can be a mixture thereof or a copolymer. Among them, the polyester resin is particularly preferably polybutylene terephthalate. Thereby, excellent followability to the concave portion 223 can be imparted to the buffer layer 3. And, when polybutylene terephthalate is contained in the first thermoplastic resin composition constituting the first release layer 1, a buffer layer 3 having excellent adhesion to the first release layer 1 can be obtained. In addition, the oxygen transmission rate of the release film 10 can be more easily set to be equal to or higher than the lower limit value. In addition, the water vapor transmission rate of the release film 10 can be more easily set to exceed the lower limit value.

[0108] In addition, although the polyester resin shows crystallinity, in the buffer layer 3, it is preferable to suppress or prevent its crystallization. Thereby, the oxygen transmission rate of the release film 10 can be more easily set to be equal to or higher than the lower limit value. And the water vapor transmission rate of the release film 10 can be more easily set to exceed the lower limit value.

[0109] And, as the polyolefin resin, there is no particular limitation. For example, polyethylene such as low-density polyethylene and high-density polyethylene, α-olefin polymers such as polypropylene, ethylene-hexene copolymers having ethylene, propylene, butene, pentene, hexene, octene, etc. as polymer components, ethylene-octene copolymers, α-olefin-(meth)acrylate copolymers, ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, etc. can be cited. One of them can be used or two or more of them can be used in combination. Among them, at least one of ethylene-vinyl acetate copolymer (ethylene vinyl acetate copolymer) and ethylene-(meth)acrylic acid copolymer (ethylene (meth)acrylic acid copolymer) is preferable. Thereby, excellent followability to the concave portion 223 can be imparted to the buffer layer 3. And the oxygen transmission rate of the release film 10 can be more easily set to be equal to or higher than the lower limit value. And the water vapor transmission rate of the release film 10 can be more easily set to exceed the lower limit value.

[0110] In the case of being set as a combination of a polyester-based resin and a polyolefin-based resin, the content of the polyester-based resin in the third thermoplastic resin composition is preferably 5% by weight or more, more preferably 8% by weight or more and 40% by weight or less. Thereby, excellent followability to the concave portion 223 can be imparted to the release film 10. And, it is possible to more easily set the oxygen transmission rate of the release film 10 to be above the lower limit value. And, it is possible to more easily set the water vapor transmission rate of the release film 10 to exceed the lower limit value.

[0111] Moreover, in the third thermoplastic resin composition constituting the buffer layer 3, in addition to the above-mentioned resin materials (thermoplastic resins), additives such as antioxidants, slip agents, anti-blocking agents, antistatic agents, colorants, and stabilizers may be included.

[0112] In addition, the storage modulus E' of the buffer 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 further preferably 1.0 MPa or more and 100 MPa or less. By setting the storage modulus E' of the buffer layer 3 at 150°C as described above, when the release film 10 is filled in the concave portion 223 in the second process, it is possible to surely suppress or prevent a part of the buffer layer 3 from protruding from the edge portion of the release film 10 and adhering to the FPC 200. Therefore, contamination of the FPC 200 can be surely suppressed or prevented. And, peeling of the release film 10 in the third process can be easily performed.

[0113] In addition, the storage modulus E' of the buffer layer 3 at 150°C can be obtained, for example, as follows: Prepare the buffer layer 3 having a width of 4 mm and a length of 20 mm in accordance with JIS K7244-4, and use a dynamic viscoelasticity measuring device (manufactured by Hitachi High-Tech Science Corporation, "DMA7100") to measure in a tensile mode, at a frequency of 1 Hz, and at a heating rate of 5°C / minute.

[0114] In addition, the average thickness Tk of the buffer layer 3 is preferably 40 μm or more and 110 μm or less, and more preferably set to 50 μm or more and 90 μm or less. Thereby, it is possible to relatively easily set the oxygen transmission rate of the release film 10 to be above the lower limit value. And, it is possible to relatively easily set the water vapor transmission rate of the release film 10 to exceed the lower limit value.

[0115] <First release layer 1>

[0116] Next, the first release layer 1 will be described. The first release layer 1 is laminated on one side of the buffer layer 3.

[0117] The first release layer 1 has flexibility. In the manufacturing method of the flexible printed circuit board 200 using the release film 10, the release film 10 is superposed in such a manner that the first release layer 1 contacts the CL film 220 provided in the FPC 200. And, in the second step of this manufacturing method, when the superposed flexible circuit board 210 and the CL film 220 are joined via the adhesive layer 222, the first release layer 1 is a layer that is pressed into following the shape of the recess 223 formed by the flexible circuit board 210 and the CL film 220 and functions as a protective (buffer) material for preventing the release film 10 from breaking. Further, the first release layer 1 has a function as a contact layer for exhibiting excellent releasability of the release film 10 from the CL film 220 (FPC 200) in the third step.

[0118] Therefore, in the second step, it is possible to surely suppress or prevent the adhesive from the adhesive layer 222 from oozing out into the recess 223 formed in the FPC 200. And, after the FPC 200 in which the flexible circuit board 210 and the CL film 220 are joined via the adhesive layer 222 provided in the CL film 220 is formed in the second step, when the release film 10 is peeled off from the FPC 200 in the third step, it is possible to surely suppress or prevent stretching and breaking from occurring in the FPC 200. And, when the polyester resin is contained in the third thermoplastic resin composition constituting the buffer layer 3, the first release layer 1 having excellent adhesion to the buffer layer 3 can be obtained.

[0119] And, regarding the first release layer 1, in the manufacturing method of the flexible printed circuit board 200, the first release layer 1 contacts the CL film 220 provided in the FPC 200. Therefore, the first release layer 1 also has a function of transferring the heat from the heated bonding plate 521 to the CL film 220 when the FPC 200 is hot-pressed in the second step of this manufacturing method.

[0120] The first release layer 1 is composed of a first thermoplastic resin composition. And, this first thermoplastic resin composition preferably mainly contains, for example, a polyester resin. Thereby, it is possible to relatively easily impart the above-described functions to the first release layer 1. Further, it is possible to relatively easily set the oxygen transmission rate of the release film 10 to be not less than the above lower limit value. And, it is possible to relatively easily set the water vapor transmission rate of the release film 10 to exceed the above lower limit value.

[0121] Moreover, the polyester resin is not particularly limited. For example, the same types as those exemplified in the above-mentioned third thermoplastic resin composition can be used. Among them, polybutylene terephthalate (PBT) is particularly preferred. Thereby, the effects obtained by using the polyester resin can be more significantly exerted. Moreover, when the third thermoplastic resin composition constituting the buffer layer 3 contains polybutylene terephthalate, the first release layer 1 having excellent adhesion to the buffer layer 3 can be obtained. In addition, it is possible to more easily set the oxygen transmission rate of the release film 10 to be above the lower limit value. And it is possible to more easily set the water vapor transmission rate of the release film 10 to exceed the lower limit value.

[0122] In addition, although the polyester resin shows crystallinity, it is preferable that the crystallization of the first release layer 1 made of the polyester resin is suppressed. More specifically, its crystallinity is preferably about 10% or more and 50% or less, more preferably about 10% or more and 35% or less. Thereby, it is possible to more easily set the oxygen transmission rate of the release film 10 to be above the lower limit value. And it is possible to more easily set the water vapor transmission rate of the release film 10 to exceed the lower limit value.

[0123] In addition, the crystallization of a crystalline resin material such as a polyester resin in the release layer 1, the release layer 2, and the buffer layer 3 can be carried out, for example, in the manufacturing method of the release film 10 described later, by setting the cooling temperature when cooling the molten state or softened state strip film 10' within the following range.

[0124] Moreover, when the first thermoplastic resin composition is mainly composed of a polyester resin, it may contain a thermoplastic resin other than the polyester resin. Examples of such a thermoplastic resin include polyolefin resins such as polyethylene, polypropylene, and poly-4-methyl-1-pentene, and polystyrene resins such as syndiotactic polystyrene. One of them can be used, or two or more of them can be used in combination.

[0125] Moreover, the first thermoplastic resin composition may further contain at least one of inorganic particles and organic particles in addition to the above-mentioned thermoplastic resin.

[0126] The inorganic particles are not particularly limited. For example, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, boron nitride, crystalline silica, amorphous silica, antimony oxide, E glass, D glass, S glass, etc. can be cited. One of them can be used, or two or more of them can be used in combination.

[0127] And, as the organic particles, there is no particular limitation, and examples thereof include polystyrene particles, acrylic particles, polyimide particles, polyester particles, silicone particles, polypropylene particles, polyethylene particles, fluororesin particles, and core-shell particles, etc. One of them can be used or two or more of them can be used in combination.

[0128] In addition, the average particle diameter of the inorganic particles and the organic particles is preferably 3 μm or more and 20 μm or less, more preferably 5 μm or more and 20 μm or less. Thus, when at least one of the inorganic particles and the organic particles is contained in the first thermoplastic resin composition, the surface roughness of the surface of the first release layer 1 on the side opposite to the buffer layer 3 can be relatively easily set within the range described below.

[0129] When the first release layer 1 has an uneven shape on its surface, the ten-point average roughness (Rz) of the surface is preferably 0.1 μm or more and 20.0 μm or less, more preferably 1.0 μm or more and 10.0 μm or less. Thus, when the release film 10 is released from the FPC 200 (flexible circuit board 210), the release can be carried out with excellent releasability. In addition, the ten-point average roughness (Rz) can be measured in accordance with JIS B0601-1994.

[0130] The storage modulus E' of the first release layer 1 forming this structure at 150 °C is preferably 50 MPa or more, more preferably 50 MPa or more and 1000 MPa or less, and further preferably 50 MPa or more and 300 MPa or less. Thus, the function of the first release layer 1 can be reliably imparted to the first release layer 1.

[0131] In addition, the storage modulus E' of the first release layer 1 at 150 °C can be obtained as follows: Prepare the first release layer 1 with a width of 4 mm and a length of 20 mm in accordance with JIS K7244-4, and use a dynamic viscoelasticity measuring device (manufactured by Hitachi High-Tech Science Corporation, "DMA7100") to measure in a tensile mode, at a frequency of 1 Hz, and a heating rate of 5 °C / minute.

[0132] And, the average thickness T1 of the first release layer 1 is preferably set to 7 μm or more and 38 μm or less, more preferably set to 10 μm or more and 30 μm or less. Thus, by setting the average thickness of the first release layer 1 within an appropriate range, the function of the first release layer 1 as described above can be more reliably imparted to the first release layer 1. And, the oxygen transmission rate of the release film 10 can be relatively easily set to be above the lower limit value. And, the water vapor transmission rate of the release film 10 can be relatively easily set to exceed the lower limit value.

[0133] Further, as described above, regarding the thickness of the first release layer 1, when the surface of the first release layer 1 on the side opposite to the buffer layer 3 has an uneven shape, the thickness is measured at positions including the convex portions in the convex portions and positions including the concave portions in the concave portions, respectively.

[0134] Moreover, in the first thermoplastic resin composition constituting the first release layer 1, in addition to the resin material, inorganic particles, and organic particles described above, additives the same as those exemplified in the third thermoplastic resin composition may also be included.

[0135] <Second release layer 2>

[0136] Next, the second release layer 2 will be described. The second release layer 2 is laminated on the other side of the buffer layer 3, that is, on the side of the buffer layer 3 opposite to the first release layer 1.

[0137] The second release layer 2 has flexibility. In the method for manufacturing the flexible printed circuit board 200 using the release film 10, the release film 10 is overlapped in such a manner that the first release layer 1 contacts the CL film 220 provided in the FPC 200. And, in the second step of this manufacturing method, when the overlapped flexible circuit board 210 and the CL film 220 are joined via the adhesive layer 222, it functions as a layer for transmitting the force from the heating press plate 521 to the buffer layer 3. In addition, the second release layer 2 has a function as a contact layer for exhibiting excellent releasability between the glass cloth 300 and the release film 10 in the third step.

[0138] Also, in the method for manufacturing the flexible printed circuit board 200, the second release layer 2 contacts the heating press plate 521 via the glass cloth 300. Therefore, the second release layer 2 also has a function of transferring the heat from the heating press plate 521 to the buffer layer 3 when thermally pressing the FPC 200 in the second step of this manufacturing method.

[0139] The second release layer 2 is composed of a second thermoplastic resin composition. And, similarly to the first thermoplastic resin composition, this second thermoplastic resin composition preferably mainly contains a polyester resin. Thereby, the above-described functions can be reliably imparted to the second release layer 2. In addition, the oxygen transmission rate of the release film 10 can be relatively easily set to be above the lower limit value. And, the water vapor transmission rate of the release film 10 can be relatively easily set to exceed the lower limit value.

[0140] Moreover, the polyester resin is not particularly limited, and for example, the same types as those exemplified in the above-mentioned third thermoplastic resin composition can be used. Among them, polybutylene terephthalate (PBT) is particularly preferred. Thereby, the effects obtained by using the polyester resin can be more significantly exerted. In addition, the oxygen transmission rate of the release film 10 can be more easily set to be above the lower limit value. And the water vapor transmission rate of the release film 10 can be more easily set to exceed the lower limit value.

[0141] In addition, although the polyester resin exhibits crystallinity, it is preferable that the crystallization of the second release layer 2 composed of the polyester resin is suppressed. More specifically, its crystallinity is preferably about 10% or more and 50% or less, more preferably about 10% or more and 35% or less. Thereby, the oxygen transmission rate of the release film 10 can be more easily set to be above the lower limit value. And the water vapor transmission rate of the release film 10 can be more easily set to exceed the lower limit value.

[0142] 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. As the thermoplastic resin, the same resins as those exemplified in the above-mentioned first thermoplastic resin composition can be used.

[0143] Moreover, the second thermoplastic resin composition may contain at least one of inorganic particles and organic particles in addition to the above-mentioned thermoplastic resin.

[0144] The inorganic particles and organic particles are not particularly limited, and the same types as those exemplified in the above-mentioned first thermoplastic resin composition can be used.

[0145] The storage modulus E' of the second release layer 2 forming this structure at 150°C is preferably 50 MPa or more, more preferably 50 MPa or more and 1000 MPa or less. Thereby, the above-mentioned functions can be reliably imparted to the second release layer 2.

[0146] Moreover, the average thickness T2 of the second release layer 2 is preferably set to be 7 μm or more and 38 μm or less, more preferably set to be 10 μm or more and 30 μm or less. Thereby, the above-mentioned functions can be more reliably imparted to the second release layer 2. And the oxygen transmission rate of the release film 10 can be relatively easily set to be above the lower limit value. And the water vapor transmission rate of the release film 10 can be relatively easily set to exceed the lower limit value.

[0147] In addition, in the second thermoplastic resin composition constituting the second release layer 2, in addition to the above-mentioned resin materials, inorganic particles, and organic particles, additives the same as those exemplified in the above-mentioned third thermoplastic resin composition can also be included.

[0148] Moreover, 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 from the perspective of substitutability, they are preferably the same or have the same properties. In addition, in the first release layer 1 and the second release layer 2, their average thicknesses may be the same or different.

[0149] In the release film 10 having the structure in which the first release layer 1, the buffer layer 3, and the second release layer 2 are laminated as described above, its average thickness Tt is preferably 40 μm or more and 180 μm or less, more preferably 50 μm or more and 180 μm or less, and further preferably 80 μm or more and 150 μm or less. Thus, the oxygen transmission rate of the release film 10 can be relatively easily set to be above the lower limit value. And the water vapor transmission rate of the release film 10 can be relatively easily set to exceed the lower limit value.

[0150] Here, in the first invention, the oxygen transmission rate of the release film 10 measured in accordance with JIS K 7126-2 is 60.0 cc / (m 2 ·atm·day) or more, preferably 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 transmission rate of the release film 10 as described above, during the period from the second process to the release of the release film 10 in the third process, in the second process, when hot pressing the FPC 200, oxygen remaining between the release film 10 and the FPC 200 can permeate through the release film 10. Therefore, when hot pressing the FPC 200, even if the FPC 200 is heated, oxidation of the circuit provided in the flexible circuit board 210 exposed in the recess 223 can be reliably suppressed or prevented.

[0151] In the first invention, the oxygen transmission rate of the release film 10 is measured under the conditions of a temperature of 23 °C and a relative humidity of 0% RH in accordance with the isobaric method of the plastic - film and sheet - gas transmission rate test method specified in JIS K 7126-2.

[0152] Moreover, in the first invention, the water vapor transmission rate of the release film 10 measured in accordance with JIS K 7129 (Method B) preferably exceeds 1.0 g / m 2 ·day (25 °C·90% RH), more preferably 1.4 g / m 2 ·day (25 °C·90% RH) or more, and further preferably 1.7 g / m 2 ·day (25 °C·90% RH) or more and 3.0 g / m 2· Below the level of "per day (25°C, 90% RH)". By setting the water vapor transmission rate of the release film 10 as described above, during the period from the second process to the third process until the release film 10 is released, in the second process, when hot-pressing the FPC 200, the water vapor contained in the air remaining between the release film 10 and the FPC 200 can permeate through the release film 10. Therefore, when hot-pressing the FPC 200 and heating the FPC 200, it is possible to surely suppress or prevent resin materials such as polyimide included in the constituent materials of the flexible circuit board 210 and the cover layer 221 from absorbing water vapor. Therefore, it is possible to surely suppress or prevent the generation of bubbles derived from the absorbed water vapor between the flexible circuit board 210 and the cover film 220 when welding the circuit provided in the flexible circuit board 210. Therefore, an FPC 200 with more excellent reliability that surely suppresses or prevents peeling between the flexible circuit board 210 and the cover film 220 can be obtained.

[0153] Moreover, in the second invention, the water vapor transmission rate of the release film 10 measured according to JIS K 7129 (Method B) exceeds 1.0 g / m 2 · per day (25°C, 90% RH), preferably 1.4 g / m 2 · per day (25°C, 90% RH) or more, more preferably 1.7 g / m 2 · per day (25°C, 90% RH) or more and 3.0 g / m 2 · per day (25°C, 90% RH) or less. By setting the water vapor transmission rate of the release film 10 as described above, during the period from the second process to the third process until the release film 10 is released, in the second process, when hot-pressing the FPC 200, the water vapor contained in the air remaining between the release film 10 and the FPC 200 can permeate through the release film 10. Therefore, when hot-pressing the FPC 200 and heating the FPC 200, it is possible to surely suppress or prevent resin materials such as polyimide included in the constituent materials of the flexible circuit board 210 and the cover layer 221 from absorbing water vapor. Therefore, it is possible to surely suppress or prevent the generation of bubbles derived from the absorbed water vapor between the flexible circuit board 210 and the cover film 220 when welding the circuit provided in the flexible circuit board 210. Therefore, an FPC 200 with more excellent reliability that surely suppresses or prevents peeling between the flexible circuit board 210 and the cover film 220 can be obtained.

[0154] In the second invention, the oxygen transmission rate of the release film 10 is measured under the conditions of a temperature of 25°C and a relative humidity of 90% RH according to JIS K 7129 (Method B).

[0155] Moreover, in the second invention, the oxygen transmission rate of the release film 10 measured according to JIS K 7126-2 is preferably 60.0 cc / (m2 ·atm·day) or more, more preferably 100.0 cc / (m 2 ·atm·day) or more, further preferably 120.0 cc / (m 2 ·atm·day) or more and 160.0 cc / (m 2 ·atm·day) or less. By setting the oxygen transmission rate of the release film 10 as described above, during the period from the second process to the third process until the release film 10 is released, in the second process, when the FPC 200 is hot-pressed, the oxygen contained in the air remaining between the release film 10 and the FPC 200 can permeate through the release film 10. Therefore, when the FPC 200 is hot-pressed, even if the FPC 200 is heated, it is possible to surely suppress or prevent the circuit provided in the flexible circuit board 210 exposed in the concave portion 223 from being oxidized. Therefore, an FPC 200 having more excellent electrical characteristics can be obtained.

[0156] Moreover, the oxygen transmission rate of the release film 10 is measured under the conditions of a temperature of 23°C and a relative humidity of 0% RH in accordance with the isobaric method of the plastic - film and sheet - gas transmission rate test method specified in JIS K 7126 - 2.

[0157] In addition, in the present embodiment, the release film 10 is composed of a laminate in which the first release layer 1, the buffer layer 3, and the second release layer 2 are laminated in sequence, but is not limited to this structure. For example, the release film 10 may be composed of a laminate having an intermediate layer such as an adhesive layer provided between at least one of the first release layer 1 and the buffer layer 3 and between the second release layer 2 and the buffer layer 3.

[0158] Moreover, as long as the release film 10 can maintain excellent releasability between the glass cloth 300 and the release film 10 in the third process, the second release layer 2 in contact with the glass cloth 300 may be omitted.

[0159] <Manufacturing Method of Release Film 10>

[0160] The release film 10 having the above structure can be manufactured, for example, by the manufacturing method described below. Hereinafter, before explaining the manufacturing method of the release film 10, first, a release film manufacturing apparatus will be explained.

[0161] Figure 6 Schematically shows the manufacturing Figure 4 A side view of the release film manufacturing apparatus for the release film 10 shown. In addition, in the following description, the Figure 6 upper side in is referred to as "upper" and the lower side as "lower".

[0162] Figure 6 The release film manufacturing apparatus 1000 shown has a film supply unit 600 and a film forming unit 700.

[0163] In this embodiment, the film supply unit 600 is composed of an extruder 610 and a T-die 620 connected to the molten resin discharge part of the extruder 610 via a pipe. Through this T-die 620, a strip-shaped film 10' in a molten state or a softened state is supplied to the film forming unit 700.

[0164] The T-die 620 is an extrusion molding part that extrudes the film 10' in a molten state or a softened state into a strip-shaped film by the co-extrusion method. By sequentially loading the constituent materials of each layer constituting the release film 10 into the T-die 620 in a molten state and extruding the molten material from the T-die 620, the strip-shaped film 10' is continuously sent out.

[0165] The film forming unit 700 includes a contact roller 710, a cooling roller 720, and a post-stage cooling roller 730. These rollers are configured to rotate independently by respective motors (driving mechanisms) not shown, and through the rotation of these rollers, the film 10' is cooled and continuously sent out. By continuously feeding the film 10' in a molten state or a softened state into the film forming unit 700, the surface of the film 10' is flattened, and the film 10' is set to a desired thickness and cooled. And, by appropriately selecting the constituent materials of each layer constituting the release film 10 loaded into the extruder 610 (T-die 620), as the cooled film 10', a release film 10 composed of a laminate in which the first release layer 1, the buffer layer 3, and the second release layer 2 are sequentially laminated can be obtained.

[0166] The release film 10 is manufactured by a method for manufacturing the release film 10 using the release film manufacturing apparatus 1000 as described above.

[0167] The method for manufacturing the release film 10 using the release film manufacturing apparatus 1000 includes an extrusion process, a forming process, and a cooling process.

[0168] <1A> First, a strip-shaped film 10' in a molten state or a softened state is extruded (extrusion process).

[0169] In this extrusion process, the constituent materials of each layer constituting the release film 10 are sequentially loaded into the extruder 610. And, the constituent materials of each layer constituting the release film 10 become a molten or softened state in the extruder 610.

[0170] <2A> Next, the surface of the film 10' is flattened, and the film 10' is set to a prescribed thickness (forming process). This process is performed between the contact roller 710 and the cooling roller 720.

[0171] <3A> Next, the surface of the film 10' is cooled (cooling process). This process is performed between the cooling roller 720 and the post-stage cooling roller 730.

[0172] The cooling temperature for cooling the surface of the film 10' by these cooling rollers 720 and the subsequent cooling rollers 730 is preferably set to about 20°C or higher and 120°C or lower, more preferably set to about 40°C or higher and 90°C or lower. Thus, when the first release layer 1, the buffer layer 3, and the second release layer 2 each contain a resin material showing crystallinity such as a polyester resin, crystallization of the resin material can be surely suppressed or prevented.

[0173] Alternatively, the structure may be as follows: Either the cooling roller 720 or the subsequent cooling roller 730 is provided with a cooling mechanism, and in one of the rollers, the film 10' is cooled.

[0174] In the above-described steps <1A> to <3A>, by appropriately selecting the constituent materials of each layer constituting the release film 10 loaded into the extruder 610 and implementing the steps, a release film 10 composed of a laminate in which the first release layer 1, the buffer layer 3, and the second release layer 2 are sequentially laminated can be obtained.

[0175] The above describes the release film and the manufacturing method of the molded product of the present invention, but the present invention is not limited thereto.

[0176] For example, in the above-described embodiment, the case where the release film of the present invention is applied to a compression molding method in which a flexible printed circuit board disposed between a heating and cooling plate is laminated in one layer is described, but the number of flexible printed circuit boards to be laminated is not limited to one layer, and may be two or more layers.

[0177] In addition, the release film of the present invention is applied to the case where a flexible printed circuit board disposed between a heating and cooling plate is pressed using a roll-to-roll press, but the present invention is not limited thereto. Pressurization of the flexible printed circuit board can be performed, for example, by a compression molding method, and in addition, it can also be performed by a vacuum pressure molding method.

[0178] [Examples]

[0179] Hereinafter, the present invention (the first invention) will be described in detail based on examples, but the present invention is not limited thereto.

[0180] 1. Preparation of raw materials

[0181] As raw materials for manufacturing the release film, the following raw materials were respectively prepared.

[0182] · Thermoplastic resin material

[0183] Low-density polyethylene (LDPE, manufactured by Ube-Maruzen Polyethlene Co., Ltd., "R300")

[0184] Ethylene-vinyl acetate copolymer (EVA, manufactured by Dow-Mitsui Polychemicals Co., Ltd., "P1403")

[0185] Polybutylene terephthalate (PBT, manufactured by Chang Chun Petrochemical Co., Ltd., "1100-630S")

[0186] Copolybutylene terephthalate (PBT, manufactured by Mitsubishi Engineering-Plastics Corporation, "5505S")

[0187] Polypropylene (PP, manufactured by Sumitomo Chemical Co., Ltd., "FH1016") Ethylene glycol-modified polyethylene terephthalate (PETG, manufactured by SELENIS, "NF411")

[0188] 2. Manufacture of the release film

[0189] <Example 1A>

[0190] First, a first thermoplastic resin composition and a second thermoplastic resin composition each composed of polybutylene terephthalate (PBT, 1100-630S) were prepared. Further, a third thermoplastic resin composition composed of 15 parts by weight of polybutylene terephthalate (PBT, 1100-630S), 35 parts by weight of ethylene-vinyl acetate copolymer (EVA, P1403), 30 parts by weight of low-density polyethylene (LDPE, R300), and 20 parts by weight of polypropylene (PP, FH1016) was prepared.

[0191] Next, by the coextrusion T-die method using the release film manufacturing apparatus 1000, the first thermoplastic resin composition, the third thermoplastic resin composition, and the second thermoplastic resin composition were coextruded to form a film, whereby a laminate in which the first release layer 1, the buffer layer 3, and the second release layer 2 were laminated in this order was formed, and thus the release film 10 of Example 1A was obtained.

[0192] In addition, when the first thermoplastic resin composition, the third thermoplastic resin composition, and the second thermoplastic resin composition were formed into a film using the release film manufacturing apparatus 1000, the cooling temperatures based on the cooling roll 720 and the post-stage cooling roll 730 were set to 60°C.

[0193] Moreover, in the obtained release film 10, the average thickness T1 of the first release layer 1 is 20 μm, the average thickness Tk of the buffer layer 3 is 80 μm, and the average thickness T2 of the second release layer 2 is 20 μm.

[0194] In addition, for the release film 10, using an oxygen permeability measuring device (manufactured by MOCON, "OX-TRAN 2 / 22L"), in accordance with the isobaric method of the plastic - film and sheet - gas permeability test method specified in JIS K 7126-2, the oxygen permeability was measured under the conditions of a temperature of 23°C and a relative humidity of 0% RH. The result was 100.0 cc / (m 2 ·atm·day).

[0195] Moreover, for the release film 10, using a water vapor permeability measuring device (manufactured by MOCON, "PERMATRAN-W3 / 34"), in accordance with K 7129 (Method B), the water vapor permeability was measured under the conditions of a temperature of 25°C and a relative humidity of 90% RH. The result was 2.5 g / m 2 ·day (25°C·90% RH).

[0196] In addition, for the first release layer 1 and the buffer layer 3, using a dynamic viscoelasticity measuring device (manufactured by Hitachi High-Tech Science Corporation, "DMA7100"), the storage modulus E' at 150°C was measured respectively in the tensile mode, at a frequency of 1 Hz, and a heating rate of 5°C / minute. The results were 160 MPa and 16 MPa.

[0197] Moreover, for the first release layer 1, using a surface roughness measuring device (manufactured by Mitutoyo Corporation., "SURFTST SJ-210"), the ten-point average roughness (Rz) of the surface exposed on the side opposite to the buffer layer 3 was measured. The result was 5 μm.

[0198] Moreover, for the first release layer 1 and the second release layer 2, using a thin film evaluation sample horizontal type X-ray diffractometer (manufactured by Rigaku Corporation, "Smart Lab"), the crystallinity was analyzed respectively by wide-angle X-ray diffraction method. The results were 33% and 35%.

[0199] In addition, based on the analysis by the wide-angle X-ray diffraction method, the crystallinity of the first release layer 1 and the second release layer 2 was calculated as follows. That is, on the diffraction measurement chart obtained by a film evaluation sample horizontal X-ray diffractometer, after drawing a linear baseline in the range of 2θ = 12.0° to 28.18°, the crystalline phase and the amorphous phase were respectively fitted as Gaussian functions. Based on the total peak area of the crystalline phase and the total peak area of the amorphous phase thus obtained, the crystallinity of the first release layer 1 and the second release layer 2 was calculated by using the following formula A.

[0200] Crystallinity (%) = Total peak area of crystalline phase / (Total peak area of crystalline phase + Total peak area of amorphous phase) × 100...A

[0201] Moreover, the measurement conditions in the film evaluation sample horizontal X-ray diffractometer were set as follows.

[0202] 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° / minute, scanning method... out-of-plane method

[0203] <Examples 2A - 4A, Comparative Example 1A>

[0204] When forming the first thermoplastic resin composition, the third thermoplastic resin composition, and the second thermoplastic resin composition into a film using the release film manufacturing apparatus 1000, the cooling temperatures based on the cooling roll 720 and the post-stage cooling roll 730 were changed as shown in Table 1. Except for this, in the same manner as in Example 1A, release films 10 with oxygen permeation rates as shown in Examples 2A - 4A and Comparative Example 1A in Table 1 were obtained.

[0205] <Examples 5A, 6A, Comparative Example 2A>

[0206] As the first thermoplastic resin composition, the second thermoplastic resin composition, and the third thermoplastic resin composition, using the structures shown in Table 1, the first release layer 1, the buffer layer 3, and the second release layer 2 were formed into films with average thicknesses as shown in Table 1. Except for this, in the same manner as in Example 1A, release films 10 with oxygen permeation rates in the thickness direction as shown in Examples 5A, 6A, and Comparative Example 2A in Table 1 were obtained.

[0207] 3. Evaluation

[0208] For the release films 10 of each example and each comparative example, the following evaluations were respectively carried out.

[0209] 3 - 1. Oxidation-based discoloration of the circuit

[0210] The release films 10 of each example and each comparative example were each made to have a structure with a width of 270 mm, and were formed by attaching a cover film 220 (manufactured by Arisawa Manufacturing Co., Ltd., "CMA0525") to a flexible circuit board 210 (manufactured by Nippon Steel Chemical & Material Co., Ltd., "MB12-12-12REG") such that the adhesive layer 222 provided in the cover film 220 was on the side of the flexible circuit board 210 to form an FPC200 (laminated body) having unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Then, using an RtoR press (manufactured by TRM Corporation, "RR Q-CURE 100TON CONTINUOUS LAMINATOR"), the release film 10 was pressed into the FPC200 laminated as shown 2 under the set conditions of 180 °C, 110 kg / cm Figure 3 . After that, as the release mechanism 60, a structure in which a rod was sandwiched between the FPC200 and the release film 10 for peeling was applied, and the release film 10 was peeled under the conditions of a conveying speed of 200 mm / s, a feed amount of 500 mm, and a distance from the heated bonding plate 521 to the release mechanism 60 of 50 mm. Also, the degree of oxidation-based discoloration of the circuit exposed in the concave portion 223 of the FPC200 was visually confirmed and evaluated according to the following criteria.

[0211] [Evaluation Criteria]

[0212] A: No oxidation-based circuit discoloration was confirmed.

[0213] B: Some oxidation-based circuit discoloration was confirmed, but it did not affect the electrical characteristics of the circuit.

[0214] C: Obvious oxidation-based circuit discoloration was confirmed and it affected the electrical characteristics of the circuit.

[0215] 3-2. Solder Resistance of Polyimide Substrate

[0216] The release films 10 of each example and each comparative example were each set to have a width of 270 mm, and were formed by attaching a cover film 220 (manufactured by Arisawa Manufacturing Co., Ltd., "CMA0525") to a flexible circuit board 210 with the adhesive layer 222 of the cover film 220 on the side of the flexible circuit board 210 to form an FPC 200 (laminated body) having unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Then, using an RtoR press (manufactured by TRM, "RR Q-CURE 100TON CONTINUOUS LAMINATOR"), at 180 °C and 110 kg / cm 2 , under the set conditions of 150 sec, the release film 10 was pressed into the FPC 200 laminated as shown in Figure 3 . After that, as the release mechanism 60, a structure in which a rod was sandwiched between the FPC 200 and the release film 10 for peeling was applied, and under the conditions of a conveying speed of 200 mm / s, a feed amount of 500 mm, and a distance from the heated pressure bonding plate 521 to the release mechanism 60 of 50 mm, the release film 10 was peeled off.

[0217] Next, the FPC 200 pressed using an RtoR press in accordance with the JPCA standard JPCA-DG04 was dried at 110 °C for 1 hour. After that, the FPC 200 was immersed in a solder solution heated to 260 °C for 10 seconds and then taken out from the solder solution. And visually confirmed whether there were bubbles generated between the flexible circuit board 210 and the cover film 220, and evaluated according to the following criteria. In addition, for the release films 10 of each example and each comparative example, the test of obtaining the FPC 200 was repeated 100 times as described above.

[0218] [Evaluation Criteria]

[0219] A: No bubbles are generated between the flexible circuit board 210 and the cover film 220.

[0220] B: The probability of bubbles being generated between the flexible circuit board 210 and the cover film 220 is less than 1%.

[0221] C: The probability of bubbles being generated between the flexible circuit board 210 and the cover film 220 is 1% or more.

[0222] 3-3. Landfillability of Release Film

[0223] The release films 10 of each example and each comparative example were each set to a structure with a width of 270 mm, and were set to be formed by attaching a cover film 220 (manufactured by Arisawa Manufacturing Co., Ltd., "CMA0525") to a flexible circuit board 210 such that the adhesive layer 222 provided in the cover film 220 was on the side of the flexible circuit board 210 to form an FPC 200 (laminated body) having unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Then, using an RtoR press (manufactured by TRM Corporation, "RR Q-CURE 100TON CONTINUOUS LAMINATOR"), at a set condition of 180 °C, 110 kg / cm 2 and 150 seconds, the release film 10 was pressed into the FPC 200 laminated as shown in Figure 3 . Then, in a state where the FPC 200 and the release film 10 were laminated, after cutting (shearing) the laminate in the thickness direction, one end of the release film 10 was held and the release film 10 was peeled off. The maximum amount of exudation of the adhesive in the recesses of the FPC 200 when viewed from above when one end of the release film 10 was held and peeled off was measured, and evaluation was performed according to the following criteria.

[0224] [Evaluation Criteria]

[0225] A: The maximum amount of exudation is less than 55 mm.

[0226] B: The maximum amount of exudation is 55 or more and less than 65 mm.

[0227] C: The maximum amount of exudation is 65 mm or more.

[0228] 3-4. Release property of the release film

[0229] The release films 10 of each example and each comparative example were each set to a structure with a width of 270 mm, and were set to be formed by attaching a cover film 220 (manufactured by Arisawa Manufacturing Co., Ltd., "CMA0525") to a flexible circuit board 210 such that the adhesive layer 222 provided in the cover film 220 was on the side of the flexible circuit board 210 to form an FPC 200 (laminated body) having unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Then, using an RtoR press (manufactured by TRM Corporation, "RR Q-CURE 100TON CONTINUOUS LAMINATOR"), at a set condition of 180 °C, 110 kg / cm 2 and 150 seconds, the release film 10 was pressed into the FPC 200 laminated as shown in Figure 3The laminated FPC200 shown. Subsequently, as the demolding mechanism 60, a structure in which a rod is sandwiched between the FPC200 and the demolding film 10 for peeling is applied, and the demolding film 10 was peeled under the conditions of a conveying speed of 200 mm / s, a feeding amount of 500 mm, and a distance from the heating press plate 521 to the demolding mechanism 60 of 50 mm. The ease of peeling (demoldability) of the demolding film 10 was evaluated according to the following criteria.

[0230] [Evaluation Criteria]

[0231] A: When peeling the demolding film, it can be peeled.

[0232] B: When peeling the demolding film, the buffer layers are welded to each other and it is difficult to peel.

[0233] 3-5. Summary

[0234] The evaluation results obtained in the above-mentioned 3-1. Oxidation-based discoloration of the circuit, 3-2. Solder resistance of the polyimide substrate, 3-3. Fillability of the demolding film, and 3-4. Demoldability of the demolding film are shown in Table 1.

[0235]

[0236] As shown in Table 1, in each example, the oxygen transmission rate of the demolding film 10 satisfies 60.0 cc / (m 2 ·atm·day) or more. As a result, it shows that the oxidation-based discoloration in the circuit exposed in the concave portion 223 of the FPC200 is suppressed.

[0237] In contrast, in each comparative example, the oxygen transmission rate of the demolding film 10 does not satisfy 60.0 cc / (m 2 ·atm·day) or more, and as a result, it shows that oxidation-based discoloration is clearly confirmed in the circuit exposed in the concave portion 223 of the FPC200.

[0238] Hereinafter, the present invention (second invention) will be described in detail according to another embodiment, but the present invention is not limited thereto.

[0239] 1. Preparation of Raw Materials

[0240] The following raw materials were respectively prepared as the raw materials for manufacturing the demolding film.

[0241] · Thermoplastic resin material

[0242] Low-density polyethylene (LDPE, manufactured by Ube-Maruzen Polyethlene Co., Ltd., "R300")

[0243] Ethylene-vinyl acetate copolymer (EVA, manufactured by Dow-Mitsui Polychemicals Co., Ltd., "P1403")

[0244] Polybutylene terephthalate (PBT, manufactured by Chang Chun Petrochemical Co., Ltd., "1100-630S")

[0245] Copolymer polybutylene terephthalate (PBT, manufactured by Mitsubishi Engineering-Plastics Corporation, "5505S")

[0246] Polypropylene (PP, manufactured by Sumitomo Chemical Co., Ltd., "FH1016") Ethylene glycol-modified polyethylene terephthalate (PETG, manufactured by SELENIS, "NF411")

[0247] 2. Manufacture of the release film

[0248] <Example 1B>

[0249] First, a first thermoplastic resin composition and a second thermoplastic resin composition each composed of polybutylene terephthalate (PBT, 1100-630S) were prepared. Further, a third thermoplastic resin composition composed of 15 parts by weight of polybutylene terephthalate (PBT, 1100-630S), 35 parts by weight of ethylene-vinyl acetate copolymer (EVA, P1403), 30 parts by weight of low-density polyethylene (LDPE, R300), and 20 parts by weight of polypropylene (PP, FH1016) was prepared.

[0250] Next, by the coextrusion T-die method using the release film manufacturing apparatus 1000, the first thermoplastic resin composition, the third thermoplastic resin composition, and the second thermoplastic resin composition were coextruded to form a film, whereby a laminate in which a first release layer 1, a buffer layer 3, and a second release layer 2 were laminated in this order was formed, and thus the release film 10 of Example 1B was obtained.

[0251] In addition, when the first thermoplastic resin composition, the third thermoplastic resin composition, and the second thermoplastic resin composition were formed into a film using the release film manufacturing apparatus 1000, the cooling temperature based on the cooling roll 720 and the post-stage cooling roll 730 was set to 60°C.

[0252] Further, in the obtained release film 10, the average thickness T1 of the first release layer 1 is 20 μm, the average thickness Tk of the buffer layer 3 is 80 μm, and the average thickness T2 of the second release layer 2 is 20 μm.

[0253] In addition, for the release film 10, using a water vapor transmission rate measuring device (manufactured by MOCON, "PERMATRAN-W3 / 34"), in accordance with K 7129 (Method B), the water vapor transmission rate was measured under the conditions of a temperature of 25°C and a relative humidity of 90% RH. The result was 2.5 g / m 2 ·day (25°C·90% RH).

[0254] Further, for the release film 10, using an oxygen transmission rate measuring device (manufactured by MOCON, "OX-TRAN 2 / 22L"), in accordance with the isobaric method of the plastic - film and sheet - gas transmission rate test method specified in JIS K 7126-2, the oxygen transmission rate was measured under the conditions of a temperature of 23°C and a relative humidity of 0% RH. The result was 100.0 cc / (m 2 ·atm·day).

[0255] In addition, for the first release layer 1 and the buffer layer 3, using a dynamic viscoelasticity measuring device (manufactured by Hitachi High-Tech Science Corporation, "DMA7100"), the storage modulus E' at 150°C was measured in the tensile mode, at a frequency of 1 Hz, and a heating rate of 5°C / minute. The results were 160 MPa and 16 MPa.

[0256] Further, for the first release layer 1, using a surface roughness measuring device (manufactured by Mitutoyo Corporation., "SURFTST SJ-210"), the ten-point average roughness (Rz) of the surface exposed on the side opposite to the buffer layer 3 was measured. The result was 5 μm.

[0257] Further, for the first release layer 1 and the second release layer 2, using a thin film evaluation sample horizontal type X-ray diffractometer (manufactured by Rigaku Corporation, "Smart Lab"), the crystallinity was analyzed by wide-angle X-ray diffraction method. The results were 33% and 35%.

[0258] In addition, based on the analysis by the wide-angle X-ray diffraction method, the crystallinity of the first release layer 1 and the second release layer 2 was calculated as follows. That is, on the diffraction measurement chart measured by the film evaluation sample horizontal X-ray diffractometer, after drawing a linear baseline in the range of 2θ = 12.0° to 28.18°, the crystal phase and the amorphous phase were respectively fitted as Gaussian functions, and based on the total peak area of the crystal phase and the total peak area of the amorphous phase thus obtained, the crystallinity of the first release layer 1 and the second release layer 2 was calculated by using the following formula A.

[0259] Crystallinity (%) = Total peak area of crystal phase / (Total peak area of crystal phase + Total peak area of amorphous phase) × 100... A

[0260] And the measurement conditions in the film evaluation sample horizontal X-ray diffractometer were set as follows.

[0261] 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

[0262] <Examples 2B - 4B, Comparative Example 1B>

[0263] When forming the first thermoplastic resin composition, the third thermoplastic resin composition, and the second thermoplastic resin composition into a film using the release film manufacturing apparatus 1000, the cooling temperatures based on the cooling roll 720 and the post-stage cooling roll 730 were changed as shown in Table 2. Except for this, in the same manner as in Example 1B, release films 10 with water vapor transmission rates shown in Table 2 for Examples 2B - 4B and Comparative Example 1B were obtained.

[0264] <Examples 5B - 7B, Comparative Examples 2B, 3B>

[0265] As the first thermoplastic resin composition, the second thermoplastic resin composition, and the third thermoplastic resin composition, the compositions shown in Table 2 were used, and the first release layer 1, the buffer layer 3, and the second release layer 2 were formed into films with average thicknesses shown in Table 2. Except for this, in the same manner as in Example 1B, release films 10 with water vapor transmission rates in the thickness direction shown in Table 2 for Examples 5B - 7B and Comparative Examples 2B, 3B were obtained.

[0266] 3. Evaluation

[0267] For the release films 10 of each example and each comparative example, the following evaluations were respectively carried out.

[0268] 3 - 1. Solder resistance of polyimide substrate

[0269] The release films 10 of each example and each comparative example were each set to have a width of 270 mm, and were formed by attaching a cover film 220 (manufactured by Arisawa Manufacturing Co., Ltd., "CMA0525") to a flexible circuit board 210 (manufactured by Nippon Steel Chemical & Material Co., Ltd., "MB12-12-12REG") such that the adhesive layer 222 provided in the cover film 220 was on the side of the flexible circuit board 210 to form an FPC200 (laminated body) having unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Then, using an RtoR press (manufactured by TRM Co., "RR Q-CURE 100TON CONTINUOUS LAMINATOR"), at a set condition of 180 °C, 110 kg / cm 2 and 150 seconds, the release film 10 was pressed into the FPC200 laminated as shown in Figure 3 . Then, as the release mechanism 60, a structure in which a rod was sandwiched between the FPC200 and the release film 10 for peeling was applied, and under the conditions of a conveying speed of 200 mm / s, a feed amount of 500 mm, and a distance from the heating press plate 521 to the release mechanism 60 of 50 mm, the release film 10 was peeled off.

[0270] Moreover, the FPC200 pressed in accordance with the JPCA standard JPCA-DG04 was dried under the conditions of 110 °C for 1 hour. Then, the FPC200 was immersed in a solder solution heated to 260 °C for 10 seconds and then taken out from the solder solution. And visually confirmed whether bubbles were generated between the flexible circuit board 210 and the cover film 220, and evaluated according to the following criteria. In addition, for the release films 10 of each example and each comparative example, the test of obtaining the FPC200 was repeated 100 times as described above.

[0271] [Evaluation Criteria]

[0272] A: No bubbles are generated between the flexible circuit board 210 and the cover film 220.

[0273] B: The probability of generating bubbles between the flexible circuit board 210 and the cover film 220 is less than 1%.

[0274] C: The probability of generating bubbles between the flexible circuit board 210 and the cover film 220 is 1% or more.

[0275] 3-2. Color change of the circuit due to oxidation

[0276] The release films 10 of each example and each comparative example were each set to have a width of 270 mm, and were formed by attaching a cover film 220 (manufactured by Arisawa Manufacturing Co., Ltd., "CMA0525") to a flexible circuit board 210 (manufactured by Nippon Steel Chemical & Material Co., Ltd., "MB12-12-12REG") such that the adhesive layer 222 provided in the cover film 220 was on the side of the flexible circuit board 210 to form an FPC 200 (laminated body) having unevenness with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Then, using an RtoR press (manufactured by TRM Corporation, "RR Q-CURE 100TON CONTINUOUS LAMINATOR"), at 180 °C, 110 kg / cm 2 and under the condition of 150 sec, the release film 10 was pressed into the FPC 200 laminated as shown in Figure 3 . After that, as the release mechanism 60, a structure in which a rod was sandwiched between the FPC 200 and the release film 10 for peeling was applied, and under the conditions of a conveying speed of 200 mm / s, a feed amount of 500 mm, and a distance from the heating press plate 521 to the release mechanism 60 of 50 mm, the release film 10 was peeled off. Also, the degree of oxidation-based discoloration of the circuit exposed in the concave portion 223 of the FPC 200 was visually confirmed and evaluated according to the following criteria.

[0277] [Evaluation Criteria]

[0278] A: No oxidation-based circuit discoloration was confirmed.

[0279] B: Some oxidation-based circuit discoloration was confirmed, but it did not affect the electrical characteristics of the circuit.

[0280] C: Obvious oxidation-based circuit discoloration was confirmed and it affected the electrical characteristics of the circuit.

[0281] 3-3. Landfillability of the release film

[0282] The release films 10 of each example and each comparative example were each set to a structure with a width of 270 mm, and were set to be formed by attaching a cover film 220 (manufactured by Arisawa Manufacturing Co., Ltd., "CMA0525") to a flexible circuit board 210 in such a manner that the adhesive layer 222 provided in the cover film 220 was on the side of the flexible circuit board 210 to form an FPC 200 (laminated body) having irregularities with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Then, using an RtoR press (manufactured by TRM Corporation, "RR Q-CURE 100TON CONTINUOUS LAMINATOR"), at a set condition of 180 °C, 110 kg / cm 2 and 150 seconds, the release film 10 was pressed into the FPC 200 laminated as shown in Figure 3 . Then, in a state where the laminated body of the FPC 200 and the release film 10 was set, after cutting (shearing) the laminated body in the thickness direction, one end of the release film 10 was held and the release film 10 was peeled off. The maximum amount of exudation of the adhesive in the concave portion of the FPC 200 was measured in a plan view when one end of the release film 10 was held and peeled off, and the evaluation was made according to the following criteria.

[0283] [Evaluation Criteria]

[0284] A: The maximum amount of exudation is less than 55 mm.

[0285] B: The maximum amount of exudation is 55 or more and less than 65 mm.

[0286] C: The maximum amount of exudation is 65 mm or more.

[0287] 3-4. Release property of the release film

[0288] The release films 10 of each example and each comparative example were each set to a structure with a width of 270 mm, and were set to be formed by attaching a cover film 220 (manufactured by Arisawa Manufacturing Co., Ltd., "CMA0525") to a flexible circuit board 210 in such a manner that the adhesive layer 222 provided in the cover film 220 was on the side of the flexible circuit board 210 to form an FPC 200 (laminated body) having irregularities with a pitch of 50 μm, a width of 50 μm, and a height of 18 μm. Then, using an RtoR press (manufactured by TRM Corporation, "RR Q-CURE 100TON CONTINUOUS LAMINATOR"), at a set condition of 180 °C, 110 kg / cm 2 and 150 seconds, the release film 10 was pressed into the FPC 200 laminated as shown in Figure 3The laminated FPC200 shown. Subsequently, as the demolding mechanism 60, a structure in which a rod is sandwiched between the FPC200 and the demolding film 10 for peeling is applied, and under the conditions of a conveying speed of 200 mm / s, a feeding amount of 500 mm, and a distance from the heating and pressing plate 521 to the demolding mechanism 60 of 50 mm, the demolding film 10 was peeled off. The ease of peeling (demoldability) of the demolding film 10 was evaluated according to the following criteria.

[0289] [Evaluation Criteria]

[0290] A: When peeling the demolding film, it can be peeled off.

[0291] B: When peeling the demolding film, the buffer layers are welded to each other and it is difficult to peel off.

[0292] 3-5. Summary

[0293] The evaluation results obtained in the above-mentioned 3-1. Solder resistance of the polyimide substrate, 3-2. Oxidation-based discoloration of the circuit, 3-3. Fillability of the demolding film, and 3-4. Demoldability of the demolding film are shown in Table 2.

[0294]

[0295] As shown in Table 2, in each example, the water vapor transmission rate of the demolding film 10 exceeded 1.0 g / m 2 ·day (25°C·90%RH), and as a result, it was shown that the generation of bubbles between the flexible circuit substrate 210 and the cover film 220 was suppressed.

[0296] In contrast, in each comparative example, the water vapor transmission rate of the demolding film 10 did not exceed 1.0 g / m 2 ·day (25°C·90%RH), and as a result, it was shown that the generation of bubbles between the flexible circuit substrate 210 and the cover film 220 was clearly confirmed.

[0297] Industrial Applicability

[0298] According to the first invention, in a demolding film having a first demolding layer composed of a first thermoplastic resin composition and a buffer layer laminated on the first demolding layer, the oxygen transmission rate of the demolding film measured according to JIS K 7126-2 satisfies 60.0 cc / (m 2 ·atm·day) or more. Therefore, for example, when obtaining a flexible printed circuit board using a flexible circuit substrate and a cover film, during the period from the filling of the recess by the demolding film to the demolding of the demolding film from the recess, it is possible to surely suppress or prevent the circuit provided on the flexible circuit substrate exposed in the recess from being oxidized. Therefore, a flexible printed circuit board with more excellent electrical characteristics can be obtained.

[0299] Further, according to the second invention, in a release film having a first release layer made of a first thermoplastic resin composition and a buffer layer laminated on the first release layer, the water vapor transmission rate of the release film measured in accordance with JIS K 7129 (Method B) exceeds 1.0 g / m 2 ·day (25°C · 90% RH). Thus, for example, when a flexible printed circuit board is obtained using a flexible circuit board and a cover film, during the period from filling the recess with the release film to releasing the release film from the recess, it is possible to surely suppress or prevent a resin material such as polyimide included as a constituent material of the flexible printed circuit board from absorbing water vapor contained in the air remaining between the release film and the flexible circuit board. Therefore, it is possible to surely suppress or prevent the generation of bubbles derived from the absorbed water vapor between the cover film and the flexible circuit board when soldering the circuit provided on the flexible circuit board. Accordingly, a flexible printed circuit board with more excellent reliability in surely suppressing or preventing peeling between the cover film and the flexible circuit board can be obtained.

[0300] Therefore, the present invention has industrial applicability.

[0301] Description of Reference Numerals

[0302] 1 - First release layer,

[0303] 2 - Second release layer,

[0304] 3 - Buffer layer,

[0305] 10 - Release film,

[0306] 10A - Release film,

[0307] 10B - Release film,

[0308] 10’ - Film,

[0309] 50 - Hot pressing mechanism,

[0310] 52 - Heating and crimping part,

[0311] 60 - Release mechanism,

[0312] 100 - Roll-to-roll press,

[0313] 200 - Flexible printed circuit board (FPC),

[0314] 210 - Flexible circuit board,

[0315] 220 - Cover film (CL film),

[0316] 221 - Cover layer,

[0317] 222 - Adhesive layer,

[0318] 223 - Concave part,

[0319] 300A - Glass cloth,

[0320] 300B - Glass cloth,

[0321] 521 - Heating and press - bonding plate,

[0322] 600 - Film supply part,

[0323] 610 - Extruder,

[0324] 620 - T - die,

[0325] 700 - Film forming part,

[0326] 710 - Contact roller,

[0327] 720 - Cooling roller,

[0328] 730 - Rear - stage cooling roller,

[0329] 1000 - Release film manufacturing device,

[0330] T1 - Average thickness of the first release layer,

[0331] T2 - Average thickness of the second release layer,

[0332] Tk - Average thickness of the buffer layer,

[0333] Tt - Average thickness of the release film.

Claims

1. A release film having a first release layer composed of a first thermoplastic resin composition and a buffer layer laminated on the first release layer, wherein the release film is characterized in that The oxygen transmission rate of the demolding film measured in accordance with JIS K 7126-2 is 60.0 cc / (m 2 ·atm·day) or more.

2. A release film having a first release layer composed of a first thermoplastic resin composition and a buffer layer laminated on the first release layer, wherein the release film is characterized in that The water vapor transmission rate of the release film measured according to JIS K 7129 (Method B) under the conditions of 25°C and 90% RH exceeds 1.0 g / m 2 ·day.

3. The release film according to claim 1 or 2, wherein, the first thermoplastic resin composition contains a polyester resin.

4. The release film according to claim 3, wherein, the polyester resin has crystallinity, and the crystallinity of the first release layer is 10% or more and 50% or less.

5. The release film according to claim 4, wherein, the buffer layer is composed of a third thermoplastic resin composition containing the polyester resin and a polyolefin resin.

6. The release film according to claim 5, wherein, the average thickness of the first release layer is 7 μm or more and 38 μm or less.

7. The release film according to claim 6, wherein, the average thickness of the buffer layer is 40 μm or more and 110 μm or less.

8. The release film according to claim 7, wherein, the average thickness of the release film is 40 μm or more and 180 μm or less.

9. The release film according to claim 1 or 2, wherein, in the first release layer, the ten-point average roughness Rz of the surface on the side opposite to the buffer layer is 0.1 μm or more and 20.0 μm or less.

10. The release film according to claim 1 or 2, wherein, the release film has a second release layer composed of a second thermoplastic resin composition laminated on the side of the buffer layer opposite to the first release layer.

11. The release film according to claim 1 or 2, wherein, the release film is used in an overlapping manner such that the surface on the first release layer side is in contact with the surface of an object formed of a material containing a semi-cured thermosetting resin.

12. A method for manufacturing a molded article, characterized in that it includes: a step of disposing the release film according to claim 1 or 2 on the object such that the first release layer faces the object side; and a step of thermocompression molding the object on which the release film is disposed. In the step of disposing the release film, the surface of the object on the side where the release film is disposed is formed of a material containing a semi-cured thermosetting resin.

Images