Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
  • B29C33/68—Release sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/40—Adhesives in the form of films or foils characterised by release liners

Definitions

• the present invention relates to a method for producing a release film and a molded product.
• a release film is commonly used when a coverlay film is bonded to a flexible circuit board with exposed circuits by hot pressing, via an adhesive layer provided on the coverlay film, to form a flexible printed circuit board, i.e., a laminate.
• the release film After laminating the coverlay film onto the flexible circuit board, the release film must be able to be peeled off from the formed flexible printed circuit board with excellent releasability.
• the release film when peeling the release film from the flexible printed circuit board, it is required that the release film exhibit excellent releasability from the flexible printed circuit board, thereby suppressing the occurrence of creases and breaks in the flexible printed circuit board.
• the object of the present invention is to provide a release film and a method for producing molded products that can quickly and successfully peel a release film from a flexible printed circuit board, regardless of the peeling method, and that can produce molded products with excellent productivity.
• a release film having a release layer A release film characterized by satisfying the conditions of F 60 ⁇ 20 and F 120 ⁇ 12 when the release layer is adhered to a film body having an adhesive layer containing an epoxy-based adhesive and then peeled from the adhesive layer and the release film is peeled off, where F 60 [N/15 mm] is the peel strength at a peel angle of 60 ° and F 120 [N/15 mm] is the peel strength at a peel angle of 120°.
• the release layer contains, as the substituent, a compound in which a part of terephthalic acid constituting polybutylene terephthalate is substituted with another dicarboxylic acid component,
• the release film according to (3) above, wherein the ratio of the other dicarboxylic acid component to all dicarboxylic acid components constituting the substitution product is 2 mol % or more and 50 mol % or less.
• the release layer contains, as the substitution product, a compound in which a part of 1,4-butanediol constituting polybutylene terephthalate is substituted with another diol component,
• the release film is applied to the surface of an object formed from a material containing a semi-cured thermosetting resin.
• the release film according to any one of (1) to (6) above, which is used by stacking the release film so that the surfaces on the release layer side are in contact with each other.
• the release film according to any one of (1) to (7) is attached to the object side so that the release layer of the release film faces the object side.
• a method for manufacturing a molded product comprising the steps of: placing the release film on the object; and performing a heat press on the object on which the release film is placed, wherein in the step of placing the release film, the surface of the object on which the release film is placed is formed from a material containing a semi-cured thermosetting resin.
• the peel strength at a peel angle of 60° is F 60 [N/15 mm] and the peel strength at a peel angle of 120° is F 120 [N/15 mm], and the conditions of F 60 ⁇ 20 and F 120 ⁇ 12 are satisfied. Therefore, for example, even when the release film is peeled manually or continuously using an apparatus, the release film can be peeled quickly and satisfactorily regardless of the peeling method, and molded products can be produced with excellent productivity.
• FIG. 1 is a side view showing the main parts of a roll-to-roll press machine used in manufacturing flexible printed circuit boards.
• 2A to 2C are vertical cross-sectional views showing the steps of a method for manufacturing a flexible printed circuit board using the roll-to-roll press machine shown in FIG.
• FIG. 3 is a vertical cross-sectional view showing a heat pressing step in the manufacturing method of a flexible printed circuit board using the roll-to-roll press machine shown in FIG.
• FIG. 4 is a longitudinal sectional view showing an embodiment of the release film of the present invention.
• FIG. 5 is a partially enlarged longitudinal sectional view of the part A of the release film shown in FIG. FIG.
• FIG. 6 is a diagram showing the state in which the releasability of the release film is evaluated at a peel angle of 60°.
• FIG. 7 is a diagram showing the state in which the releasability of the release film is evaluated at a peel angle of 120°.
• Fig. 1 is a side view showing the main parts of a roll-to-roll press used in manufacturing a flexible printed circuit board
• Fig. 2 is a vertical cross-sectional view showing each step in a manufacturing method for a flexible printed circuit board using the roll-to-roll press shown in Fig. 1
• Fig. 3 is a vertical cross-sectional view showing a heat pressing step in a manufacturing method for a flexible printed circuit board using the roll-to-roll press shown in Fig. 1.
• the upper side in Figs. 1 to 3 will be referred to as "top” or “upper”, the lower side as “bottom” or “lower”, the left side as "left”, and the right side as "right”.
• the roll-to-roll press machine 100 (RtoR press machine) is equipped with a conveying means (not shown) for conveying the release film 10 (10A, 10B), flexible printed circuit board 200 (hereinafter sometimes referred to as "FPC") and glass cloths 300A, 300B, a heat pressing means 50 for bonding the flexible circuit board 210 and coverlay film 220 (hereinafter sometimes referred to as "CL film”) provided in the FPC 200 by heat pressing the CL film 220 to the flexible circuit board 210 using the release film 10, and a releasing means 60 for releasing (peeling) the release film 10 from the FPC 200 in which the CL film 220 is bonded to the flexible circuit board 210.
• a conveying means not shown
• FPC flexible printed circuit board 200
• CL film coverlay film
• the conveying means conveys the FPC 200, release films 10A and 10B, and glass cloths 300A and 300B, each wound around a different unwinding roller, along their respective longitudinal directions by rotating tensioners (tension rollers), and after processing by the heat pressing means 50 and the releasing means 60, winds them onto a take-up roller.
• Each roller is made of a metal material, such as stainless steel.
• the rotation axes (central axes) of these rollers face in the same direction, and they are spaced apart from one another.
• the heat pressing means 50 has a heat pressing section 52 .
• the thermocompression unit 52 has a pair of thermocompression plates 521.
• the thermocompression plates 521 are transported by a transport means and are disposed above and below the overlapping glass cloth 300A, release film 10A, FPC 200, release film 10B, and glass cloth 300B.
• the thermocompression plates 521 heat and pressurize the FPC 200 via the glass cloths 300A, 300B and the release films 10A, 10B. Therefore, as shown in FIG. 2( a), the curing reaction of the adhesive layer 222 provided on the CL film 220 progresses due to this heating, and in the FPC 200, the overlapping flexible circuit board 210 and the CL film 220 are bonded via the adhesive layer 222.
• the film-like coverlay 221 having the recess 223 is bonded to the flexible circuit board 210 via the adhesive layer 222 (see FIG. 2(a)). Furthermore, when the FPC 200 is heated and pressurized, i.e., when the coverlay 221 and the flexible circuit board 210 are bonded via the adhesive layer 222, the release film 10 is embedded in the recess 223 formed in the coverlay 221. Therefore, seepage of adhesive from the adhesive layer 222 into the recess 223 is suppressed (see FIG. 2(b)).
• the adhesive that constitutes the adhesive layer 222 is not particularly limited, but examples include epoxy-based adhesives, acrylic-based adhesives, urethane-based adhesives, etc.
• the FPC 200 Before being heated and compressed by the heating and compression plate 521, the FPC 200 is in a laminated state with the flexible circuit board 210 and the CL film 220 superimposed on top of each other, but the flexible circuit board 210 and the CL film 220 are not bonded via the adhesive layer 222 provided on the CL film 220. Then, by compression using the heating and compression plate 521, the adhesive layer 222 provided on the CL film 220 is brought into close contact with the flexible circuit board 210, and in this state, heating by the heating and compression plate 521 progresses the curing reaction of the adhesive layer 222, thereby bonding the flexible circuit board 210 and the CL film 220 via the adhesive layer 222.
• the release means 60 is disposed downstream in the conveying direction relative to the heat press means 50.
• This release means 60 is configured to separate the FPC 200 from the release films 10A and 10B.
• the release film 10 is embedded in a recess 223 formed in the coverlay 221, thereby bonding the release film 10 to the CL film 220 (FPC 200).
• the release means 60 is configured to peel (release) the release film 10 from the CL film 220 (FPC 200) (see FIG. 2(c)). Therefore, the action of the release means 60 results in the FPC 200, which is configured such that the flexible circuit board 210 and the CL film 220 are bonded via the adhesive layer 222, and is peeled from the release film 10.
• the release means 60 has a round bar 600.
• the round bar 600 is sandwiched (inserted) between the FPC 200 and the release film 10, thereby allowing the release film 10 to be peeled off from the FPC 200.
• the round bar 600 has a circular cross section and a diameter of approximately 3 mm to 20 mm.
• the release means 60 is not limited to the round bar 600, but may also be a wedge-shaped member.
• the release means 60 may also have other configurations, such as a configuration in which a vacuum device is installed on the outside and release is performed by vacuuming, or a configuration in which release is performed by blowing air between the bonded body and the release films 10A, 10B.
• a flexible printed circuit board 200 can be manufactured using the roll-to-roll press machine 100 described above.
• a method for manufacturing an FPC 200 using this roll-to-roll press machine 100 is described below.
• the molded product manufacturing method of the present invention is applied to the manufacturing method of this FPC 200.
• the method for manufacturing the FPC 200 includes the following steps: a first step in which sheet-like glass cloth 300A, release film 10A, FPC 200, release film 10B, and glass cloth 300B are laminated together in this order to form a laminate; a second step in which the laminate is heat-pressed to bond the coverlay 221 (CL film 220) to the flexible circuit board 210 via the adhesive layer 222 in the FPC 200; and a third step in which the release film 10 (10A, 10B) is released from the FPC 200 to obtain the FPC 200 in which the CL film 220 is bonded to the flexible circuit board 210.
• the method for laminating each component (film) onto the laminate is not particularly limited; for example, the components may be laminated while being pressed with a roll, or may be laminated while being pressed with a press.
• the components may also be laminated in any order. For example, all components may be laminated at the same time, or the coverlay film 220 and flexible circuit board 210 may be laminated in advance, and then the other components may be laminated at the same time.
• the formation of the laminate in this first step constitutes the step of placing the release film 10 on the object (FPC 200) in the method for manufacturing a molded product of the present invention.
• the release film 10A adheres closely to the coverlay 221 and is embedded in the recesses 223 formed in the coverlay 221, thereby suppressing the seepage of adhesive from the adhesive layer 222 into the recesses 223.
• the temperature to which the FPC 200 is heated is not particularly limited, but is preferably between 100°C and 250°C, and more preferably between 150°C and 200°C.
• the pressure set in the thermocompression unit 52 when pressurizing the FPC 200 is not particularly limited, but is preferably set to between 1 MPa and 14 MPa, and more preferably between 5 MPa and 14 MPa.
• the conveying speed for conveying the laminate is preferably set to 40 mm/sec or more and 400 mm/sec or less, and more preferably 100 mm/sec or more and 350 mm/sec or less.
• the laminate in the second step (main step), the laminate is hot-pressed using hot-press means 50, and in the peeling step (next step), the adhesion time until release film 10 is peeled from the bonded body is preferably set to 1.0 sec or more and 10.0 sec or less, and more preferably 4.0 sec or more and 7.0 sec or less.
• the second step constitutes a step in the molded product manufacturing method of the present invention in which the object (FPC 200) on which the release film 10 is disposed is subjected to heat pressing. Furthermore, if the coverlay 221 (insulating layer) is formed from a material containing a semi-cured thermosetting resin, the coverlay 221 constitutes the surface of the object (FPC 200) on which the release film 10 is disposed. The release film 10 is then layered on the surface of this coverlay 221 so that the surface on the first release layer 1 side is in contact with the surface of this coverlay 221.
• the release film 10 can maintain the shape of the coverlay 221 with the recesses 223 formed therein while curing the thermosetting resin, thereby enabling the coverlay 221 (molded product) to be molded on the flexible circuit board 210 with excellent precision. Furthermore, because the adhesion time is set within the above range, the release film 10 can promote the curing reaction of the thermosetting resin that constitutes the coverlay 221 while maintaining the shape of the coverlay 221 with the recesses 223 formed therein.
• the method for manufacturing a molded product of the present invention includes a first step of placing a release film 10 on an object (FPC 200) so that the first release layer 1 of the release film 10 faces the object (FPC 200), and a second step of performing a heat press on the object (FPC 200) on which the release film 10 has been placed.
• the surface of the object (FPC 200) on which the release film 10 is placed is formed of a material containing a semi-cured thermosetting resin. This allows the release film 10 to maintain the shape of the coverlay 221 with the recesses 223 formed therein while curing the thermosetting resin, thereby enabling the coverlay 221 (molded product) to be molded on the flexible circuit board 210 with excellent precision.
• the release film 10 allows the curing reaction of the thermosetting resin that constitutes the coverlay 221 to proceed while maintaining the shape of the coverlay 221 with the recesses 223 formed therein.
• heating may be performed using infrared rays or a heating roll.
• the release films 10 (10A, 10B) are released from the FPC 200. That is, the release films 10A and 10B are peeled off from the bonded body of the coverlay film 220 and the flexible circuit board 210. This results in an FPC 200 in which the CL film 220 is bonded to the flexible circuit board 210 (peeling step, see FIGS. 1, 2(c), and 3).
• coverlay film 220 and flexible circuit board 210 glass cloth 300A, release film 10A, release film 10B, and glass cloth 300B are wound up on their respective winding rollers.
• the FPC 200 in which the flexible circuit board 210 and the CL film 220 are bonded via the adhesive layer 222 provided on the CL film 220, is continuously obtained in a state wound around the winding roller.
• flexible printed circuit boards 200 can be manufactured continuously.
• the process may include a step of heating the flexible printed circuit board 200 wound around the winding roller, or the wound flexible printed circuit board 200 cut into individual sheets, in an oven or the like to further promote the curing reaction of the thermosetting resin that makes up the coverlay 221, thereby hardening the coverlay 221.
• the release film of the present invention is applied to the release film 10 used in the manufacture of this flexible printed circuit board 200. Below, we will explain the release film 10 to which the release film of the present invention is applied.
• FIG. 4 is a longitudinal sectional view showing an embodiment of the release film of the present invention
• FIG. 5 is a partially enlarged longitudinal sectional view of part A of the release film shown in FIG.
• the release film 10 is composed of a laminate in which a first release layer 1, a cushion layer 3, and a second release layer 2 are laminated in this order, and is used by overlapping it with the surface of the first release layer 1 in contact with the CL film 220 provided on the FPC 200.
• the cushion layer 3 is disposed as an intermediate layer between the first release layer 1 and the second release layer 2, as shown in Figures 4 and 5 .
• This cushion layer 3 is made of a third thermoplastic resin composition, and it is preferable that this third thermoplastic resin composition contains multiple types of thermoplastic resins while providing the release film 10 with the ability to fill the recesses 223.
• thermoplastic resins examples include a combination of polyester resin and polyolefin resin, a combination of two polyolefin resins, and a combination of polyamide resin and polyolefin resin.
• polyester resin and polyolefin resin examples include a combination of polyester resin and polyolefin resin, a combination of two polyolefin resins, and a combination of polyamide resin and polyolefin resin.
• Polyester-based resins include, but are not limited to, polyethylene terephthalate (PET), polycyclohexane terephthalate (PCT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycyclohexanedimethylene terephthalate, polypropylene terephthalate, etc., and one or more of these can be used in combination.
• the polyester-based resin may be a blend or copolymer of these.
• polybutylene terephthalate is particularly preferred as the polyester-based resin. This allows the cushion layer 3 to have excellent conformability to the recesses 223.
• the cushion layer 3 can exhibit excellent adhesion to the first release layer 1.
• the polyolefin resin is not particularly limited, and examples include ⁇ -olefin polymers such as polyethylene (e.g., low-density polyethylene and high-density polyethylene), polypropylene, and ⁇ -olefin copolymers containing ethylene, propylene, butene, pentene, hexene, octene, or the like as polymer components, such as ethylene and hexene copolymers, ethylene and octene copolymers, ⁇ -olefin and (meth)acrylic acid ester copolymers, ethylene and vinyl acetate copolymers, and ethylene and (meth)acrylic acid copolymers.
• ⁇ -olefin polymers such as polyethylene (e.g., low-density polyethylene and high-density polyethylene), polypropylene, and ⁇ -olefin copolymers containing ethylene, propylene, butene, pentene,
• ethylene and vinyl acetate copolymers ethylene-vinyl acetate copolymer
• ethylene and (meth)acrylic acid copolymers ethylene-(meth)acrylic acid copolymer
• the content of the polyester-based resin in this third thermoplastic resin composition is preferably 5% by weight or more, and more preferably 8% by weight or more and 40% by weight or less. This allows the release film 10 to have excellent conformability to the recesses 223.
• the third thermoplastic resin composition constituting the cushion layer 3 may contain, in addition to the resin material (thermoplastic resin) described above, additives such as a nucleating agent, antioxidant, slip agent, antiblocking agent, antistatic agent, colorant, and stabilizer.
• additives such as a nucleating agent, antioxidant, slip agent, antiblocking agent, antistatic agent, colorant, and stabilizer.
• the storage modulus E' of the cushion layer 3 at 150°C is preferably 0.1 MPa or greater, more preferably 0.5 MPa or greater and 150 MPa or less, and even more preferably 1 MPa or greater and 100 MPa or less.
• the storage modulus E' of the cushion layer 3 at 150°C can be obtained, for example, in accordance with JIS K7244-4, by preparing a cushion layer 3 with a width of 4 mm and a length of 20 mm and measuring it using a dynamic viscoelasticity measuring device (Hitachi High-Tech Science Corporation, "DMA7100") in tension mode at a frequency of 1 Hz and a heating rate of 5°C/min.
• a dynamic viscoelasticity measuring device Hitachi High-Tech Science Corporation, "DMA7100”
• the average thickness Tk of this cushion layer 3 is preferably set to be 40 ⁇ m or more and 110 ⁇ m or less, and more preferably 50 ⁇ m or more and 90 ⁇ m or less.
• First release layer 1 (release layer)> Next, a description will be given of the first release layer 1.
• the first release layer 1 is laminated on one surface of the cushion layer 3, as shown in Figs.
• the first release layer 1 is flexible, and in the aforementioned method for manufacturing a flexible printed circuit board 200 using the release film 10, the release film 10 is superimposed on the CL film 220 of the FPC 200 so that the first release layer 1 comes into contact with the CL film 220. Then, in the second step of this manufacturing method, when the superimposed flexible circuit board 210 and CL film 220 are bonded via the adhesive layer 222, the first release layer 1 is pressed into the recess 223 formed by the flexible circuit board 210 and the CL film 220, and functions as a protective (buffering) material that prevents the release film 10 from breaking. Furthermore, in the third step, the first release layer 1 functions as a contact layer that ensures excellent releasability of the release film 10 from the CL film 220 (FPC 200).
• the release film 10 can effectively suppress or prevent the adhesive from seeping out of the adhesive layer 222 into the recesses 223 formed in the FPC 200. Furthermore, after the formation of the FPC 200 in the second step, in which the flexible circuit board 210 and the CL film 220 are bonded via the adhesive layer 222 provided on the CL film 220, when the release film 10 is peeled from the FPC 200 in the third step, the release film 10 can effectively suppress or prevent the FPC 200 from elongating or breaking. Furthermore, when the third thermoplastic resin composition constituting the cushion layer 3 contains a polyester-based resin, the first release layer 1 can exhibit excellent adhesion to the cushion layer 3.
• the first release layer 1 is in contact with the CL film 220 provided on the FPC 200. Therefore, in the second step of this manufacturing method, when the FPC 200 is heat-pressed, the first release layer 1 also has the function of transferring heat from the heat-bonding plate 521 to the CL film 220.
• the release film 10 when the release film 10 is peeled from a state in which the first release layer 1 is adhered to an adhesive layer of a film body having an adhesive layer containing an epoxy-based adhesive, and the peel strength at a peel angle of 60° is F 60 [N/15 mm] and the peel strength at a peel angle of 120° is F 120 [N/15 mm], the conditions of F 60 ⁇ 20 and F 120 ⁇ 12 are satisfied.
• the release film can be peeled quickly and satisfactorily regardless of the peeling method, and molded products can be produced with excellent productivity.
• F 60 ⁇ 20 is not satisfied, that is, if F 60 is too large, the release film 10 cannot be rapidly and satisfactorily peeled off when continuously peeling the release film 10 using the above-mentioned releasing means 60.
• F 120 ⁇ 12 is not satisfied, that is, if F 120 is too large, the release film 10 cannot be rapidly and satisfactorily peeled off when manually peeling the release film 10. In other words, if either F 60 ⁇ 20 or F 120 ⁇ 12 is not satisfied, the effects of the present invention cannot be obtained.
• F 60 and F 120 were measured as follows.
• F60 A coverlay film (HXC-1220 manufactured by DuPont) containing an epoxy adhesive as the first release layer 1 and a release film were attached to the release film 10, and the film was pressed at 180°C and 3 MPa, and cut into a 15 mm x 100 mm piece. Then, using a peel tester (VPA-H100 manufactured by Kyowa Interface Science Co., Ltd.), the peel strength of the release film 10 was measured at a peel angle of 60° and a peel rate of 200 mm/min.
• PVA-H100 manufactured by Kyowa Interface Science Co., Ltd.
• a coverlay film (HXC-1220 manufactured by DuPont) containing an epoxy adhesive as the first release layer 1 and a release film were attached to the release film 10, and the film was pressed at 180°C and 3 MPa, and cut into a 15 mm x 100 mm piece. Then, using a peel tester (VPA-H100 manufactured by Kyowa Interface Science Co., Ltd.), the peel strength of the release film 10 was measured at a peel angle of 120° and a peel rate of 200 mm/min.
• release film 10 has first release layer 1, and when release film 10 is peeled from a state in which first release layer 1 is adhered to an adhesive layer of a film body having an adhesive layer containing an epoxy-based adhesive, and the peel strength at a peel angle of 60° is F 60 [N/15 mm] and the peel strength at a peel angle of 120° is F 120 [N/15 mm], the conditions of F 60 ⁇ 20 and F 120 ⁇ 12 are satisfied.
• the release film can be peeled quickly and satisfactorily regardless of the peeling method, and molded products can be produced with excellent productivity.
• F60 ⁇ 20 it is sufficient that F60 ⁇ 20, but it is preferable that 2 ⁇ F60 ⁇ 19, and more preferably 3 ⁇ F60 ⁇ 18.
• F60 is equal to or less than the upper limit, the effects of the present invention can be more significantly obtained.
• F60 is equal to or more than the lower limit, it is possible to ensure tracking ability.
• F 120 ⁇ 12 it is sufficient that F 120 ⁇ 12, but it is preferable that 1 ⁇ F 120 ⁇ 11, and more preferably 2 ⁇ F 120 ⁇ 10.
• F 120 is equal to or less than the upper limit, the effects of the present invention can be more significantly obtained.
• F 120 is equal to or more than the lower limit, it is possible to ensure tracking ability.
• F 60 ⁇ 19 and F 120 ⁇ 11 it is preferable that F 60 ⁇ 18 and F 120 ⁇ 10.
• F 60 and F 120 are equal to or less than the upper limit values, the effects of the present invention can be more significantly obtained.
• condition F 60 /F 120 > 1.62 is satisfied, and it is more preferable that the condition F 60 /F 120 > 1.72 is satisfied.
• F 60 /F 120 is equal to or greater than the lower limit, the effects of the present invention are more pronounced.
• the first release layer 1 is made of a first thermoplastic resin composition.
• the first release layer 1 may be made of any material as long as it satisfies the above-mentioned conditions of F 60 and F 120 , but it is preferable that it contains polybutylene terephthalate (first resin component) and a substitute (second resin component) in which at least one of terephthalic acid and 1,4-butanediol that constitute polybutylene terephthalate is partially substituted with another monomer component. This makes it possible to obtain the effects of the present invention more significantly.
• first release layer 1 is made of a material containing polybutylene terephthalate (first resin component) and a substitute (second resin component).
• first resin component is not limited to the following.
• the first release layer 1 contains polybutylene terephthalate (PBT) as a first resin component.
• PBT polybutylene terephthalate
• Polybutylene terephthalate is a polymer compound formed by polymerizing terephthalic acid as a dicarboxylic acid and 1,4-butanediol as a diol component, and incorporating an ester structure.
• the first resin component is not limited to the above and may be, for example, other polyester-based resins such as polyethylene terephthalate.
• the second resin component is a substituted product (copolymer) in which at least one of terephthalic acid and 1,4-butanediol constituting polybutylene terephthalate is partially substituted with another monomer component.
• the second resin component contains terephthalic acid as a dicarboxylic acid component and 1,4-butanediol as a diol component, as well as at least one of a dicarboxylic acid component other than terephthalic acid and a diol component other than 1,4-butanediol.
• Dicarboxylic acid components other than terephthalic acid include, for example, isophthalic acid and naphthalenedicarboxylic acid, and one or more selected from these can be used in combination.
• Diol components other than 1,4-butanediol include, for example, 1,2-butanediol and 1,6-hexanediol, and one or more selected from these can be used in combination. This allows for more pronounced effects of the present invention.
• the first release layer 1 preferably contains, as the second resin component (substitution product), a compound in which part of the terephthalic acid constituting polybutylene terephthalate has been substituted with another dicarboxylic acid component, and the proportion of the other dicarboxylic acid component in the total dicarboxylic acid components constituting the substitution product is preferably 2 mol % or more and 50 mol % or less. This allows for more pronounced effects of the present invention.
• the first release layer 1 preferably contains, as the second resin component (substitution product), a compound in which part of the 1,4-butanediol that constitutes polybutylene terephthalate has been substituted with another diol component, and the proportion of the other diol component in the total diol components that constitute the substitution product is preferably 1 mol% or more and 20 mol% or less. This allows for more pronounced effects of the present invention.
• the first release layer 1 may contain multiple types of resin components as the second resin component (substitute).
• the content of the substituent (second resin component) in the first release layer 1 is preferably 20 parts by mass or more and 100 parts by mass or less, more preferably 25 parts by mass or more and 100 parts by mass or less, and even more preferably 30 parts by mass or more and 100 parts by mass or less, in the resin composition that constitutes the first release layer 1. This makes it possible to obtain the effects of the present invention more significantly.
• the first release layer 1 may contain, in addition to the aforementioned polybutylene terephthalate (first resin component) and the substituted body (second resin component), further another resin component (third resin component).
• the first release layer 1 may contain, in addition to the resin described above, at least one of inorganic particles and organic particles.
• Inorganic particles are not particularly limited, but examples include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, alumina, aluminum nitride, aluminum borate whiskers, boron nitride, crystalline silica, amorphous silica, antimony oxide, E-glass, D-glass, S-glass, etc., and one or more of these can be used in combination.
• organic particles are not particularly limited, but examples include polystyrene particles, acrylic particles, polyimide particles, polyester particles, silicone particles, polypropylene particles, polyethylene particles, fluororesin particles, and core-shell particles, and one or more of these can be used in combination.
• the inorganic particles and organic particles preferably have an average particle size of 3 ⁇ m or more and 20 ⁇ m or less, and more preferably 5 ⁇ m or more and 20 ⁇ m or less.
• the first release layer 1 having such a configuration preferably has a storage modulus E' at 150°C of 50 MPa or more, more preferably 50 MPa or more and 1000 MPa or less, and even more preferably 50 MPa or more and 300 MPa or less. This ensures that the first release layer 1 can be imparted with the functions of the first release layer 1 described above.
• the storage modulus E' of the first release layer 1 at 150°C can be obtained in accordance with JIS K7244-4 by preparing a first release layer 1 having a width of 4 mm and a length of 20 mm, and measuring it using a dynamic viscoelasticity measuring device (Hitachi High-Tech Science Corporation, "DMA7100") in tension mode, at a frequency of 1 Hz, and at a heating rate of 5°C/min.
• a dynamic viscoelasticity measuring device Hitachi High-Tech Science Corporation, "DMA7100”
• the average thickness T1 of this first release layer 1 is preferably set to be 7 ⁇ m or more and 38 ⁇ m or less, and more preferably 10 ⁇ m or more and 30 ⁇ m or less. This allows the average thickness of the first release layer 1 to be set within an appropriate range, thereby more reliably imparting the first release layer 1 with the functions described above as the first release layer 1.
• the thickness of the first release layer 1 shall be measured at a position including the convex portions in the case of convex portions, and at a position including the concave portions in the case of concave portions.
• the release film 10 is laminated to the other side of the cushion layer 3, i.e., the side of the cushion layer 3 opposite the first release layer 1, and has a second release layer 2 made of a second thermoplastic resin composition.
• the second release layer 2 is flexible, and in the aforementioned method for manufacturing a flexible printed circuit board 200 using the release film 10, the release film 10 is superimposed on the CL film 220 of the FPC 200 so that the first release layer 1 comes into contact with it.
• the second release layer 2 functions as a layer that transmits the force from the heat-bonding plate 521 to the cushion layer 3.
• the second release layer 2 functions as a contact layer that ensures excellent releasability between the glass cloth 300 and the release film 10.
• the second release layer 2 contacts the thermocompression plate 521 via the glass cloth 300. Therefore, in the second step of this manufacturing method, when the FPC 200 is hot-pressed, the second release layer 2 also has the function of transferring heat from the thermocompression plate 521 to the cushion layer 3.
• the second release layer 2 is made of a second thermoplastic resin composition. Furthermore, like the first thermoplastic resin composition, this second thermoplastic resin composition preferably contains primarily a polyester-based resin. This ensures that the second release layer 2 is endowed with the aforementioned functions.
• the polyester-based resin is not particularly limited, but can be, for example, the same as those listed for the third thermoplastic resin composition described above, with polybutylene terephthalate (PBT) being particularly preferred. This allows the effects achieved by using a polyester-based resin to be more pronounced.
• PBT polybutylene terephthalate
• the second thermoplastic resin composition when it is primarily composed of a polyester-based resin, it may also contain a thermoplastic resin other than a polyester-based resin.
• thermoplastic resins include polyolefin-based resins such as polyethylene, polypropylene, and poly-4-methyl-1-pentene, and polystyrene-based resins such as syndiotactic polystyrene, and one or more of these can be used in combination.
• the second thermoplastic resin composition may contain, in addition to the thermoplastic resin described above, at least one of inorganic particles and organic particles.
• the inorganic particles and organic particles are not particularly limited, but the same particles as those described above can be used.
• the second release layer 2 having this configuration preferably has a storage modulus E' at 150°C of 50 MPa or more, and more preferably 50 MPa or more and 1000 MPa or less. This ensures that the second release layer 2 is provided with the aforementioned functions.
• the average thickness T2 of this second release layer 2 is preferably set to be 7 ⁇ m or more and 38 ⁇ m or less, and more preferably 10 ⁇ m or more and 30 ⁇ m or less. This allows the second release layer 2 to more reliably achieve the aforementioned functions.
• the second thermoplastic resin composition constituting the second release layer 2 may contain, in addition to the resin materials, inorganic particles, and organic particles described above, additives similar to those listed for the third thermoplastic resin composition.
• constituent materials of the first release layer 1 and the second release layer 2 may be the same or different, but from the standpoint of substitutability, it is preferable that they are the same or of the same quality. Furthermore, the average thicknesses T1 and T2 of the first release layer 1 and the second release layer 2 may be the same or different.
• the average thickness Tt is preferably 50 ⁇ m or more and 180 ⁇ m or less, and more preferably 80 ⁇ m or more and 150 ⁇ m or less.
• the release film 10 is composed of a laminate in which the first release layer 1, the cushion layer 3, and the second release layer 2 are laminated in this order, but is not limited to this configuration.
• the release film 10 may be composed of a laminate including an intermediate layer, such as an adhesive layer, disposed at least either between the first release layer 1 and the cushion layer 3 or between the second release layer 2 and the cushion layer 3.
• the second release layer 2 that comes into contact with the glass cloth 300 may be omitted from the release film 10 in the third step, as long as excellent releasability can be maintained between the glass cloth 300 and the release film 10.
• the release film of the present invention is described as being applied to a press molding method in which flexible printed circuit boards are stacked in one layer between thermocompression plates, but the number of stacked flexible printed circuit boards is not limited to one layer and may be two or more layers.
• release film of the present invention is intended to be applied when a roll-to-roll press is used to pressurize a flexible printed circuit board placed between thermocompression plates, this is not limited to this, and pressure can also be applied to the flexible printed circuit board using, for example, a press molding method, or even a vacuum/pressure molding method.
• Thermoplastic resin material Low-density polyethylene (LDPE, manufactured by Ube Maruzen Polyethylene Co., Ltd., "R300”) Ethylene vinyl acetate copolymer (EVA, manufactured by Mitsui-Dow Polychemicals, "P1403”) Polybutylene terephthalate (PBT, manufactured by Chang Chun Petrochemical Co., Ltd., "1100-630S”) Copolymerized polybutylene terephthalate (PBT, manufactured by Mitsubishi Engineering Plastics Corporation, “5505S”) Copolymerized polybutylene terephthalate (PBT, manufactured by Bell Polyester Products, Inc., "P02220”)
• thermoplastic resin composition consisting of 70 parts by weight of polybutylene terephthalate (PBT, 1100-630S) and 30 parts by weight of copolymerized polybutylene terephthalate (PBT, 5505S).
• a second thermoplastic resin composition was prepared, consisting of 100 parts by weight of polybutylene terephthalate (PBT, 1100-630S).
• a cushion layer resin composition consisting of 40 parts by weight of low-density polyethylene (LDPE, R300), 40 parts by weight of ethylene-vinyl acetate copolymer (EVA, P1403), and 20 parts by weight of polybutylene terephthalate (PBT, 1100-630S).
• LDPE low-density polyethylene
• EVA ethylene-vinyl acetate copolymer
• PBT polybutylene terephthalate
• the first thermoplastic resin composition was then formed into a film using an extrusion T-die method, thereby obtaining a first release layer 1.
• the first release layer 1 was subjected to the extrusion T-die method using the third thermoplastic resin composition and the second thermoplastic resin composition, and each was formed into a film, thereby forming a laminate in which the cushion layer 3 and the second release layer 2 were laminated in this order on the first release layer 1.
• This laminate was then annealed at 80°C for 5 minutes, thereby obtaining the release film 10 of Example 1.
• the average thickness T1 of the first release layer 1 was 20 ⁇ m
• the average thickness Tk of the cushion layer 3 was 80 ⁇ m
• the average thickness T2 of the second release layer 2 was 20 ⁇ m.
• Examples 2 to 4 As the first thermoplastic resin composition, polybutylene terephthalate (PBT, 1100-630S), copolymerized polybutylene terephthalate (PBT, 5505S), and copolymerized polybutylene terephthalate (PBT, manufactured by Bell Polyester Products, Inc., "P02220") were used, and the compounding ratios were changed as shown in Table 1. The release films 10 of Examples 2 to 4 were obtained in the same manner as in Example 1.
• Comparative Examples 1 and 2 The release films 10 of Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the blending ratio of polybutylene terephthalate (PBT, 1100-630S) and copolymerized polybutylene terephthalate (PBT, 5505S) was changed as the first thermoplastic resin composition.
• PBT polybutylene terephthalate
• PBT copolymerized polybutylene terephthalate
• a release film 10 having a width of 270 mm was superimposed so that the first release layer 1 was in contact with a flexible circuit board composed of a coverlay film having an epoxy adhesive ("CMA0530” manufactured by Arisawa Manufacturing Co., Ltd.) and a flexible copper-clad laminate ("MB18-25-18CEG” manufactured by Nippon Steel Chemical & Material Co., Ltd.), and pressed using a RtoR press machine ("RR Q-CURE 100TON CONTINUOUS LAMINATOR” manufactured by TRM Corporation) under set conditions of 180°C, 110 kg/ cm2 , and 150 seconds.
• a coverlay film having an epoxy adhesive (“CMA0530” manufactured by Arisawa Manufacturing Co., Ltd.) and a flexible copper-clad laminate ("MB18-25-18CEG” manufactured by Nippon Steel Chemical & Material Co., Ltd.
• RtoR press machine (“RR Q-CURE 100TON CONTINUOUS LAMINATOR” manufactured by TRM Corporation) under set conditions of 180°C, 110 kg/ cm2 , and 150 seconds
• the first release layer 1 was set to satisfy the conditions F 60 ⁇ 20 and F 120 ⁇ 12 when the peel strength at a peel angle of 60° was F 60 [N/15 mm] and the peel strength at a peel angle of 120° was F 120 [N/15 mm], and as a result, excellent release properties were demonstrated regardless of the peeling method.
• the comparative examples were not set to satisfy the conditions of F 60 ⁇ 20 and F 120 ⁇ 12, and as a result, the results showed that the releasability was not excellent.
• the present invention provides a release film that can be quickly and successfully peeled off regardless of the peeling method, whether the release film is peeled off manually or continuously using a device, and also provides a method for producing molded products with excellent productivity. Therefore, the present invention has industrial applicability.

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