CN118302294B

CN118302294B - Mold release film and method for producing molded article

Info

Publication number: CN118302294B
Application number: CN202280077855.7A
Authority: CN
Inventors: 鸿池昭吾; 榎本阳介
Original assignee: Sumitomo Bakelite Co Ltd
Current assignee: Sumitomo Bakelite Co Ltd
Priority date: 2021-11-29
Filing date: 2022-10-05
Publication date: 2024-11-29
Anticipated expiration: 2042-10-05
Also published as: JP2023080003A; TW202327894A; JP7243906B1; CN118302294A; WO2023095453A1

Abstract

The release film (10) of the present invention has a release layer (1) constituting at least one release surface, wherein the release layer (1) contains 30 mass% or more of a polyester resin, and the release film (10) satisfies the following requirement 1. The requirement 1 is that when the storage elastic modulus under 70 ℃ obtained by measuring the release film (10) using a dynamic viscoelasticity measuring device (stretching mode, frequency 1Hz, temperature rising speed 5 ℃ C./min) is A1, and the storage elastic modulus after the release film (10) is treated under 175 ℃,120 seconds and 2MPa is A2, the relation that A2/A1 is not less than 1.2 is satisfied.

Description

Mold release film and method for producing molded article

Technical Field

The present invention relates to a release film and a method for producing a molded article. More specifically, the present invention relates to a release film, a method for producing a molded article using the release film, a method for recycling the release film, and a method for producing the release film of the 2 nd step.

Background

The release film is generally used when a molded article is produced or when a laminate of different materials is produced. Such a release film is used, for example, when a flexible printed circuit board (hereinafter, also referred to as "FPC") is produced by bonding a cover film (coverlay film) (hereinafter, also referred to as "CL film") to a circuit-exposed flexible film (hereinafter, also referred to as "circuit-exposed film") via an adhesive by hot stamping.

Here, the adhesive flows to fill fine irregularities on the circuit surface during hot stamping, and the flexible film and the cover film can be brought into close contact. If the release film has insufficient following properties, there may be a problem that the adhesive cannot fill the fine irregularities and flows out directly to the outside.

In recent years, automation of manufacturing FPCs by a manufacturing method such as a roll-to-roll (RtoR) method and improvement of productivity have been achieved. For example, patent document 1 discloses a multilayer release film in which a release layer comprising polybutylene terephthalate (a) as a main component and having a thickness in the range of 32 to 73 μm and a tensile elastic modulus at 23 ℃ of 1100 to 1400mpa is laminated on both sides of a buffer layer in order to suppress the occurrence of wrinkles due to roll-to-roll.

Prior art literature

Patent literature

Patent document 1 Japanese patent application laid-open No. 2015-214028.

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, with miniaturization and thinning of circuit boards, the technical level of various characteristics of release films has been increasing. In addition, excessive stress may occur when the release film is peeled off due to the high speed of the manufacturing process or the like.

Therefore, the conventional release film disclosed in patent document 1 has room for improvement in terms of achieving both of the following property and the release property at a high level.

Means for solving the technical problems

The present inventors have conducted intensive studies with a view to developing a release film that exhibits high releasability when peeling the release film, reduces stress caused by peeling, and can obtain good follow-up properties capable of adhering to fine irregularities at the time of hot stamping.

As a result, it was found that it is effective to control the behavior in dynamic viscoelasticity measurement of a release film having a release layer containing 30 mass% or more of a polyester resin from the viewpoint of achieving a release film that combines both of the good following property and the high release property.

Accordingly, the present inventors have focused on the behavior in dynamic viscoelasticity measurement, devised new indexes to embody the unique properties of the release film of the present invention, and completed the present invention. In other words, by controlling the behavior in dynamic viscoelasticity measurement, the release film of the present invention can exhibit the unique property of good follow-up property at the time of hot stamping and high release property at the time of peeling.

According to the present invention, the following techniques are provided in relation to a release film, a method for producing a molded article using the release film, a method for recycling the release film, and a method for producing the release film 2.

[1] A release film having a release layer constituting at least one release surface, wherein the release layer contains 30 mass% or more of a polyester resin, and the release film satisfies the following requirement 1. The requirement 1 is that when the storage elastic modulus of the release film measured by a dynamic viscoelasticity measuring device under conditions of a stretching mode, a frequency of 1Hz and a temperature rising speed of 5 ℃ per minute under conditions of 70 ℃ is set as A1, and the storage elastic modulus of the release film after being treated under conditions of 175 ℃,120 seconds and 2MPa is set as A2, the relation that A2/A1 is not less than 1.2 is satisfied.

[2] The release film according to [1], wherein the release layer contains 1 or more kinds selected from the group consisting of polyethylene terephthalate resin (PET), polyethylene terephthalate glycol resin (PETG), polybutylene terephthalate resin (PBT), polytrimethylene terephthalate resin (PTT) and polyhexamethylene terephthalate resin (PHT) as the polyester resin.

[3] The release film according to [1] or [2], wherein the release film further has a buffer layer having a sea-island structure.

[4] The release film according to [3], wherein the buffer layer contains 1 or 2 or more kinds selected from the group consisting of polyethylene terephthalate resin (PET), polyethylene terephthalate glycol resin (PETG), polybutylene terephthalate resin (PBT), polytrimethylene terephthalate resin (PTT) and polyhexamethylene terephthalate resin (PHT).

[5] The release film according to [3] or [4], wherein the thickness (μm) of the buffer layer is 50 to 90% relative to the thickness (μm) of the entire release film.

[6] The release film according to any one of [1] to [5], wherein the release film satisfies the following requirement 2. Condition 2 is that when the loss elastic modulus at 70 ℃ obtained by measuring the release film using a dynamic viscoelasticity measuring device under conditions of a stretching mode, a frequency of 1Hz, and a temperature rising rate of 5 ℃ per minute is set to be B1, and the loss elastic modulus after the release film is treated under conditions of 175 ℃, 120 seconds, and 2MPa is set to be B2, the relationship of B1< B2 is satisfied.

[7] The release film according to any one of [1] to [6], wherein the release film satisfies the following requirement 3. The requirement 3 is that when the storage elastic modulus at 100 ℃ obtained by measuring the release film using a dynamic viscoelasticity measuring device under conditions of a stretching mode, a frequency of 1Hz, and a temperature rising rate of 5 ℃ per minute is C1, and the storage elastic modulus after the release film is treated under conditions of 175 ℃, 120 seconds, and 2MPa is C2, the relationship of C2/C1 of 1.3 or more is satisfied.

[8] The release film according to any one of [1] to [7], wherein the release film satisfies the following requirement 4. The requirement 4 is that the relation of D2/D1 of 1.2 or more is satisfied when D1 is the storage elastic modulus at 150 ℃ obtained by measuring the release film using a dynamic viscoelasticity measuring device under conditions of a stretching mode, a frequency of 1Hz, and a temperature rising rate of 5 ℃ per minute, and D2 is the storage elastic modulus after the release film is treated at 175 ℃, 120 seconds, and 2 MPa.

[9] The release film according to any one of [1] to [8], wherein an arithmetic average roughness Ra of the release surface is 0.1 to 3.5 μm.

[10] The release film according to any one of [1] to [9], wherein the thickness of the release film is 50 to 200 μm.

[11] The release film according to any one of [1] to [10], wherein the release film is suitable for use in a roll-to-roll manner.

[12] The release film according to any one of [1] to [10], wherein the release film is suitable for a rapid press mode.

[13] A method for producing a molded article, comprising the steps of disposing the release film on the object such that the one release surface of the release film of any one of [1] to [12] is on the object side, and hot stamping the object on which the release film is disposed.

[14] The method of producing a molded article according to [13], wherein in the step of disposing the release film, a surface of the object on which the release film is disposed is formed of a material containing a thermosetting resin.

[15] The method of producing a molded article according to [13] or [14], wherein the molded article is a flexible circuit board.

[16] A method of recycling a release film, comprising the steps of pulverizing the release film used in the method of producing a molded article according to any one of [13] to [15], processing the pulverized product into a material for a release film, and forming a2 nd release film using the material for a release film.

[17] The method for recycling a release film according to [16], wherein the 2 nd release film has a2 nd release layer and a2 nd buffer layer formed on the 2 nd release layer, and the 2 nd buffer layer is formed from the film raw material.

[18] A method for producing a2 nd release film, wherein the 2 nd release film production method comprises a step of pulverizing the release film used in the method for producing a molded article according to any one of [13] to [15], a step of processing a film-forming raw material, and a step of forming a2 nd release film using the film-forming raw material.

[19] The method for producing a2 nd release film according to [18], wherein the 2 nd release film has a2 nd release layer and a2 nd buffer layer formed on the 2 nd release layer, and the 2 nd buffer layer is formed from the film raw material.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a release film having both good follow-up property and high release property is provided. Further, according to the present invention, a reusable release film can be provided.

Drawings

Fig. 1 is a cross-sectional view schematically showing a cross-section of a release film according to the present embodiment.

Fig. 2 is a schematic diagram showing an example of a method of using the release film according to the present embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The drawings are for illustration only, and the shape, the dimensional ratio, etc. of each member in the drawings do not necessarily correspond to an actual article.

In the present specification, unless otherwise specified, the "a to b" in the description of the numerical range indicates a or more and b or less. For example, "1 to 5 mass%" means "1 mass% or more and 5 mass% or less". In the present specification, the MD direction means a longitudinal direction (Machine Direction) and a resin flow direction, and the TD direction means a transverse direction (TRANSVERSE DIRECTION) and a direction orthogonal to the MD direction.

< Release film >

As shown in fig. 1, the release film 10 has a laminated structure in which a release layer 1 containing 30 mass% or more of a polyester resin, a buffer layer 3, and a release layer 2 are laminated in this order in the thickness direction. The release layer 1 is disposed on one surface of the release film 10, and the release layer 2 is disposed on the other surface of the release film 10, which is also called a sub-release layer.

In the present embodiment, the release film 10 is disposed so that the release layer 1 side contacts a molding object including a circuit or the like. That is, the surface on the side contacting the molding object is referred to as the 1 st release surface of the release film 10, and the surface on the opposite side to the surface on the side contacting the molding object is referred to as the 2 nd release surface of the release film 10.

The surface of the molding object in the previous stage of disposing the release film 10 is generally formed of a material containing a thermosetting resin in a semi-cured state.

The release film 10 is disposed on the surface of a molded object formed of a material containing the thermosetting resin in the above-described semi-cured state. Then, the desired molded article can be obtained by performing hot stamping in a state where the release film 10 is disposed on the surface of the molded object.

The release film 10 satisfies the following requirement 1.

The requirement 1 is that when the storage elastic modulus under 70 ℃ obtained by measuring the release film 10 using a dynamic viscoelasticity measuring device (stretching mode, frequency 1Hz, temperature rising rate 5 ℃ C./min) is A1, and the storage elastic modulus after the release film 10 is treated under 175 ℃, 120 seconds, 2MPa is A2, the relation that A2/A1 is not less than 1.2 is satisfied.

175 ℃,120 Seconds, and 2MPa in element 1 are treatments at the time of hot stamping using the release film 10. That is, the element 1 means that the storage elastic modulus A1 increases under the condition of 70 ℃ before and after hot stamping using the release film 10.

Thus, the release film 10 of the present embodiment can obtain good follow-up property before hot stamping, and can obtain high release property due to the increased storage elastic modulus A1 after hot stamping. The details of this mechanism are not clear, but it is presumed that the release layer 1 of the release film 10 contains 30 mass% or more of the polyester resin, and crystallization of the polyester resin proceeds by heat at the time of hot stamping, whereby the storage elastic modulus A1 can be effectively improved.

Further, since the crystallization of the polyester resin progresses after the hot stamping of the release film 10 of the present embodiment, the used release film 10 has a relatively high storage elastic modulus. Therefore, even when the used release film 10 is processed into a film-forming material by grinding and then processed into a release film again, good releasability can be easily obtained. This can improve the recyclability of the release film 10.

In this embodiment, the release film 10 satisfies A2/A1.gtoreq.1.2, but is preferably A2/A1.gtoreq.1.3, more preferably A2/A1.gtoreq.1.4.

On the other hand, the upper limit of A2/A1 is not particularly limited, but is preferably 5.0 or less, more preferably 4.0 or less from the viewpoint of maintaining good handleability, workability, etc., and is more preferably 3.8 or less from the viewpoint of obtaining a stable balance between the following property and the mold release property.

The storage elastic modulus A1 is preferably 100 to 500MPa, more preferably 120 to 300MPa. By setting the storage elastic modulus A1 within this numerical range, good follow-up properties can be obtained while maintaining good mold release properties.

The storage elastic modulus A2 is preferably 200 to 800MPa, more preferably 300 to 650MPa. By setting the storage elastic modulus A2 within this numerical range, high releasability can be obtained. Further, the reusability of the used release film 10 can be improved.

The release film 10 further preferably satisfies the following requirement 2. This makes it easy to improve the follow-up property while maintaining high mold release properties. That is, by controlling the loss elastic modulus at 70 ℃ of the release film 10, the properties such as tackiness and flexibility can be easily controlled, and the follow-up property can be more easily obtained.

Condition 2 is that the relation of B1< B2 is satisfied when the loss elastic modulus under 70 ℃ obtained by measuring the release film 10 using a dynamic viscoelasticity measuring device (stretching mode, frequency 1Hz, temperature rising rate 5 ℃ per minute) is B1, and the loss elastic modulus after the release film 10 is treated under 175 ℃, 120 seconds, 2MPa is B2.

In this embodiment, the release film 10 preferably satisfies B1< B2, more preferably B2/B1. Gtoreq.1.05, and still more preferably B2/B1. Gtoreq.1.10.

On the other hand, the upper limit of B2/B1 is not particularly limited, but is preferably 6.0 or less, more preferably 5.0 or less, from the viewpoint of maintaining good handleability, workability, and the like.

The loss elastic modulus B1 is preferably 10 to 80MPa, more preferably 20 to 50MPa. By setting the loss elastic modulus B1 within this numerical range, it is easy to improve the follow-up property while maintaining good mold release property.

The loss elastic modulus B2 is preferably 20 to 160MPa, more preferably 30 to 140MPa. By setting the loss elastic modulus B2 within this numerical range, both high mold release property and follow-up property can be achieved. Further, the reusability of the used release film 10 can be improved.

The release film 10 further preferably satisfies the following requirement 3. Thus, higher releasability can be stably obtained.

The requirement 3 is that when the storage elastic modulus at 100 ℃ obtained by measuring the release film 10 using a dynamic viscoelasticity measuring device (stretching mode, frequency 1Hz, temperature rising rate 5 ℃ C./min) is C1, and the storage elastic modulus after the release film 10 is treated at 175 ℃, 120 seconds, and 2MPa is C2, the relationship of C2/C1 not less than 1.5 is satisfied.

In this embodiment, the release film 10 preferably satisfies C2/C1.gtoreq.1.3, more preferably C2/C1.gtoreq.1.4, and still more preferably C2/C1.gtoreq.1.5.

On the other hand, the upper limit of C2/C1 is not particularly limited, but is preferably 5.0 or less, more preferably 2.0 or less, from the viewpoint of maintaining good handleability, workability, and the like.

The storage elastic modulus C1 is preferably 50 to 250MPa, more preferably 70 to 200MPa. By setting the storage elastic modulus C1 within this numerical range, it is easy to improve the follow-up property while maintaining good mold release property.

The storage elastic modulus C2 is preferably 90 to 300MPa, more preferably 100 to 270MPa, and still more preferably 120 to 250MPa. By setting the storage elastic modulus C2 within this numerical range, both high mold release property and follow-up property can be achieved. Further, the reusability of the used release film 10 can be improved.

The release film 10 preferably further satisfies the following requirement 4. Thus, high releasability can be stably obtained, and recyclability of the release film 10 can be improved.

The requirement 4 is that the relation of D2/D1 of 1.2 or more is satisfied when D1 is the storage elastic modulus at 150 ℃ obtained by measuring the release film using a dynamic viscoelasticity measuring device under conditions of a stretching mode, a frequency of 1Hz, and a temperature rising rate of 5 ℃ per minute, and D2 is the storage elastic modulus after the release film is treated at 175 ℃, 120 seconds, and 2 MPa.

In this embodiment, the release film 10 preferably satisfies D2/D1.gtoreq.1.2, more preferably satisfies D2/D1.gtoreq.1.3.

The storage elastic modulus D1 is preferably 100 to 500MPa, more preferably 120 to 300MPa. By setting the storage elastic modulus D1 within this numerical range, good follow-up property can be obtained while maintaining good mold release property.

The storage elastic modulus D2 is preferably 200 to 800MPa, more preferably 300 to 650MPa. By setting the storage elastic modulus D2 within this numerical range, high releasability can be obtained. Further, the reusability of the used release film 10 can be improved.

The release film 10 satisfying the above-described requirements 1 to 4 can be realized by combining known methods such as selection and combination of resin materials constituting the release layer 1 and the buffer layer 3, control of the thickness of the release film 10 and the respective layers, and the like. Further, the surface roughness of the release surface of the release layer 1 can be controlled to improve the releasability.

The thickness of the entire release film 10 is preferably 50 μm or more and 200 μm or less, more preferably 80 μm or more and 150 μm or less, and still more preferably 100 μm or more and 120 μm or less. Thus, when a molded article is produced, a pressing pressure can be uniformly applied to the release film 10 without any variation. This can effectively improve the elastic modulus. Further, by setting the thickness of the entire release film 10 to the above lower limit value or more, the releasability can be easily improved, while by setting the thickness of the entire release film 10 to the above upper limit value or less, the balance between releasability and follow-up property can be easily achieved.

The respective layers will be described in detail below.

Release layer 1 (release layer 1)

The release layer 1 is a layer that forms a surface (1 st release surface) that contacts the molding object when hot stamping is performed using the release film 10.

The release layer 1 contains 30 mass% or more of a polyester resin. That is, the release layer 1 is formed of a resin composition containing 30 mass% or more of a polyester resin. This can improve the elastic modulus after hot stamping by advancing crystallization of the polyester resin during hot stamping. As a result, the releasability can be improved.

The release layer 1 preferably contains 40 mass% or more of a polyester resin, more preferably 50 mass% or more, still more preferably 70 mass% or more, and particularly preferably 90 mass% or more. This can further improve heat resistance and facilitate improvement of releasability.

The polyester resin according to the present embodiment is a polyester which can be obtained by using a 2-valent acid such as terephthalic acid or a derivative having an ester-forming ability as an acid component and a diol having 2 to 10 carbon atoms, a 2-valent alcohol or a derivative having an ester-forming ability as a diol component.

The polyester resin may be 1 or 2 or more selected from polyethylene terephthalate resin (PET), polyethylene terephthalate glycol resin (PETG), polybutylene terephthalate resin (PBT), polytrimethylene terephthalate resin (PTT) and polyhexamethylene terephthalate resin (PHT), or a copolymer based on these resins. Among them, PBT, PETG and PBT-PTMG copolymers are preferably contained, and PBT-PTMG copolymers are more preferably used in combination.

Since the crystallization rate of PBT is relatively high, it can cause sufficient crystallization in hot stamping, contributing to an increase in the storage elastic modulus of the release film 10. This increases the rigidity of the release film 10, and can improve the releasability. Further, by containing 2 or more kinds of polyester resins, an effect of increasing the storage elastic modulus may be obtained by utilizing the reaction of the two.

The PBT-PTMG copolymer is not particularly limited, and has an MFR of preferably 5 to 80 (cm ²/10 min), more preferably 20 to 60 (cm ²/10 min), still more preferably 30 to 50 (cm ²/10 min) at 250℃and 2.16 kg.

Further, amorphous polyesters other than PETG may be further contained. Since the amorphous polyester has a reduced storage elastic modulus at the hot stamping temperature, it can have good followability to the object.

Specific examples of the amorphous polyester include 1, 4-cyclohexanedimethanol-copolymerized polyethylene terephthalate, isophthalic acid-copolymerized polyethylene terephthalate, polyethylene terephthalate cyclohexane dimethanol (PCTG), and the like, which are structures obtained by substituting ethylene glycol of polyethylene terephthalate with cyclohexanedimethanol.

The release layer 1 may contain, in addition to the polyester resin, other thermoplastic resins, antioxidants, slip agents (SLIP AGENT), antiblocking agents, antistatic agents, colorants such as dyes and pigments, additives such as stabilizers, impact resistance imparting agents such as fluororesins and silicone rubbers, and organic or inorganic particles.

Examples of the thermoplastic resin include a copolymer resin obtained by copolymerizing a poly-4-methyl-1-pentene resin (polymethylpentene resin), a syndiotactic polystyrene resin (SPS), a polypropylene resin (PP), and other components. These may be used in 1 kind or in combination of 2 or more kinds.

In the present embodiment, the release layer 1 may contain particles. Thus, releasability and appropriate strength can be obtained, and the occurrence of wrinkles or bubbles in the release film 10 can be suppressed, thereby obtaining a good appearance.

The average particle diameter d50 of the particles is preferably 3 μm or more, more preferably 5 μm or more, and still more preferably 8 μm or more. On the other hand, the average particle diameter d50 of the particles is preferably 35 μm or less, more preferably 25 μm or less, and still more preferably 18 μm or less.

By setting the average particle diameter d50 of the particles to the above lower limit value or more, the rigidity of the release film 10 can be improved, and the releasability from the surface roughened FPC can be improved. On the other hand, by setting the average particle diameter d50 of the particles to the above upper limit value or less, the balance between releasability and follow-up property can be made good, and a molded article having a good appearance can be produced.

The particles are preferably inorganic particles from the viewpoint of improving the rigidity of the release film 10.

Examples of the inorganic particles include particles of 1 or 2 or more kinds selected from the group consisting of silica such as crystalline silica, amorphous silica and fused silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, zinc oxide, aluminum nitride, aluminum borate whisker, boron nitride, antimony oxide, E glass, D glass, S glass and zeolite. The inorganic particles may be used alone of only 1 kind, or may be used in combination of different kinds. The inorganic particles may be surface-treated with a silane coupling agent or the like for the purpose of improving adhesion to the resin, or core-shell particles obtained by organic coating treatment of the inorganic particles may be used for the purpose of improving dispersibility.

From the viewpoint of improving the rigidity of the release film, silica such as crystalline silica, amorphous silica and fused silica is preferable, and fused silica having a spherical shape is more preferable.

The content of the particles is preferably 0.1% by weight or more and 30% by weight or less, more preferably 1% by weight or more and 20% by weight or less, and still more preferably 5% by weight or more and 15% by weight or less, relative to the total amount of the release layer 1.

By setting the content of the particles of the release layer 1 to the above lower limit value or more, good releasability can be easily obtained, while by setting the content of the particles of the release layer 1 to the above upper limit value or less, cost reduction can be achieved while maintaining good releasability.

The thickness (μm) of the release layer 1 is 15% or less, preferably 12% or less, and more preferably 10% or less, relative to the thickness of the release film 10 as a whole. As a result, the release layer 1 deforms easily against deformation of the buffer layer 3 described later, and the outflow of the adhesive can be highly suppressed. On the other hand, the thickness (μm) of the release layer 1 is preferably 4% or more, more preferably 5% or more, relative to the thickness of the release film 10 as a whole. Thus, good releasability of the release film 10 can be maintained.

Further, the thickness of the release layer 1 is preferably 3 μm or more, more preferably 7 μm or more, and still more preferably 10 μm or more from the viewpoint of obtaining an appropriate strength. On the other hand, from the viewpoint of improving the embeddability into a molded article, the thickness of the release layer 1 is preferably 35 μm or less, more preferably 30 μm or less, and still more preferably 25 μm or less.

By setting the thickness of the release layer 1 to the above lower limit value or more, good release properties can be easily obtained, while by setting the thickness of the release layer 1 to the above upper limit value or less, good follow-up properties can be easily obtained, and cost reduction can be realized.

The arithmetic average roughness Ra of the 1 st release surface of the release film 10 is preferably 0.1 to 3.5 μm, more preferably 0.5 to 3.0 μm, and still more preferably 1.0 to 2.5 μm.

By setting the arithmetic average roughness Ra to the above lower limit value or more, the mold release property can be improved. On the other hand, by setting the arithmetic average roughness Ra to the above upper limit value or less, the following property can be maintained well.

In addition, the arithmetic average roughness Ra can be measured in accordance with JIS B0601 (1994).

The arithmetic average roughness Ra of the release film 10 can be adjusted by controlling the particle diameter and the content of the particles contained in the release layer 1, the thicknesses of the release film 10 and the release layer 1, and the method of manufacturing the release film 10. That is, for example, if the particle diameter of the particles is larger than the thickness of the release layer 1, the irregularities due to the particles tend to be noticeable on the 1 st release surface of the release film 10, and if the content of the particles is large, the irregularities due to the particles tend to be noticeable on the 1 st release surface of the release film 10.

Release layer 2

The release layer 2 is a layer that forms a surface (the 2 nd release surface) that contacts the hot stamping plate when hot stamping is performed using the release film 10.

The release layer 2 is formed using a resin composition. The resin composition used for the release layer 2 can be the same as the resin composition described in the release layer 1. The resin compositions used in the release layers 1 and 2 may be the same or different. The release layer 2 may be formed using the same material as the release layer 1 or may be different from the release layer.

The release layer 2 may contain particles in the same manner as the release layer 1. The average particle diameter d50 and the content of the particles may be the same as or different from those of the release layer 1.

The thickness of the release layer 2 is preferably 10 μm or more, more preferably 15 μm or more, from the viewpoint of obtaining appropriate strength. On the other hand, from the viewpoint of improving the embeddability into a molded article, the thickness of the release layer 2 is preferably 50 μm or less, more preferably 40 μm or less.

The thickness of the release layer 2 may be the same as or different from the thickness of the release layer 1.

The thickness of the release layer 2 is preferably the same as that of the release layer 1, and more preferably the same material/composition, from the viewpoint of eliminating the difference between the front surface and the back surface of the release film 10 and simplifying the handling.

Buffer layer 3

The buffer layer 3 is interposed between the release layer 1 and the release layer 2. The cushioning layer 3 imparts a suitable stiffness to the entire release film 10 while imparting a good follow-up property.

The buffer layer 3 is formed using a resin composition. The resin composition forming the buffer layer 3 preferably contains a polyester resin.

As the polyester resin, the same resin as the polyester resin exemplified in the release layer 1 described above can be used. Among them, the buffer layer 3 preferably contains 1 or 2 or more selected from polyethylene terephthalate resin (PET), polyethylene terephthalate glycol resin (PETG), polybutylene terephthalate resin (PBT), and more preferably 2 or more are used in combination. Among them, polyethylene terephthalate glycol resin (PETG) and polybutylene terephthalate resin (PBT) are preferably used in combination. This makes the transesterification easier, and can increase the rate of increase in elastic modulus after hot stamping.

The buffer layer may contain 1 or 2 or more selected from the group consisting of ethylene copolymers, alpha-olefin polymers such as polyethylene, low Density Polyethylene (LDPE), polypropylene (PP), alpha-olefin copolymers having propylene, butene, pentene, hexene, methylpentene, etc. as polymer components, engineering plastic resins such as Polyethersulfone (PES), polyphenylene sulfide (PPS), polymethylpentene resins, rubber components, etc. Among them, it is preferable to include 1 or 2 or more selected from ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA), and Low Density Polyethylene (LDPE).

Examples of the ethylene copolymer include 1 or 2 or more selected from the group consisting of ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic ester copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene cycloolefin copolymer (COC), and ionomer resin (ION).

Examples of the rubber component include styrene-based thermoplastic elastomers such as styrene-butadiene copolymers and styrene-isoprene copolymers, olefin-based thermoplastic elastomers, amide-based elastomers, thermoplastic elastomer materials such as polyester-based elastomers, natural rubber, isoprene rubber, chloroprene rubber, and rubber materials such as silicone rubber.

Examples of the mixture constituting the buffer layer 3 include a mixture of a polyester resin and an α -olefin polymer, a mixture of a polyester resin, an α -olefin polymer and an ethylene copolymer, a mixture of a polyester resin, an α -olefin polymer and a rubber component, a mixture of a polyester resin and a polyamide resin, and more specifically, a mixture of PBT, PETG and an α -olefin polymer, a mixture of PBT, an α -olefin polymer and a rubber component, a mixture of PBT, an ethylene copolymer and an α -olefin polymer.

The buffer layer 3 may contain additives such as antioxidants, slip agents, antiblocking agents, antistatic agents, colorants such as dyes and pigments, stabilizers, impact resistance imparting agents such as fluororesins and silicone rubbers, and inorganic fillers such as titanium oxide, calcium carbonate and talc. And, compatibilizing agents may also be included to control the compatibility of the various resins.

In the present embodiment, the buffer layer 3 preferably has an island-in-sea structure. That is, the buffer layer 3 is formed using 2 or more resins having different characteristics, and one of the resins preferably forms a dispersed phase and the other resin forms a continuous phase. By having the island structure, cushioning properties are easily obtained, so that good follow-up properties can be maintained while mold release properties are improved. Further, it is assumed that the island structure is aggregated by hot stamping, and thus the elastic modulus of the release film 10 can be improved, and the releasability can be improved.

For example, the continuous phase (sea) may be a polyolefin resin, the dispersed phase (island) may be a polyester resin, or the dispersed phase (island) may be a polyolefin resin, and the continuous phase (sea) may be a polyester resin.

The island structure can be confirmed by observing the cross section of the buffer layer 3 using a Scanning Electron Microscope (SEM) or a Transmission Electron Microscope (TEM).

The thickness (μm) of the buffer layer 3 is preferably 50 to 90%, more preferably 55 to 87%, and even more preferably 60 to 85% of the thickness (μm) of the entire release film 10.

By setting the ratio (%) of the thickness of the buffer layer 3 to the above lower limit value or more, good cushioning properties of the release film 10 can be obtained quickly, and the adhesive can be prevented from flowing out and the following property can be improved. On the other hand, by setting the ratio (%) of the thickness of the buffer layer 3 to the above-described upper limit value or less, the release property can be maintained well, and the outflow of the buffer layer 3 itself by hot stamping can be suppressed.

The thickness of the buffer layer 3 is preferably 30 μm or more, more preferably 45 μm or more, still more preferably 60 μm or more, and particularly preferably 75 μm or more.

The thickness of the buffer layer 3 is preferably 150 μm or less, more preferably 120 μm or less, and still more preferably 100 μm or less.

By setting the thickness of the buffer layer 3 to the above lower limit value or more, the cushioning properties of the release film 10 can be obtained quickly, and the outflow of the adhesive can be suppressed, and the following properties can be improved. On the other hand, by setting the thickness of the buffer layer 3 to the above upper limit value or less, releasability can be maintained well.

Examples of the method for forming the buffer layer 3 include known methods such as an air-cooled or water-cooled inflation (inflation) extrusion method and a T-die extrusion method.

< Method for producing Release film 10 >

The release film 10 can be produced by a known method such as a coextrusion method, an extrusion lamination method, a dry lamination method, or a inflation method. The release film 10 may be formed by bonding the release layers 1, 3 and 2 by a laminator or the like after separately producing them, and preferably by an air-cooled or water-cooled coextrusion inflation method or a coextrusion T-die method. Among them, a method of forming a film by a coextrusion T-die method is particularly preferable from the viewpoint of excellent control of the thickness of each layer. The release layer 1, the buffer layer 3, and the release layer 2 may be bonded directly or via an adhesive layer.

< Method for producing molded article and method for Using mold Release film >

Next, a method for manufacturing a molded article according to the present embodiment will be described.

The method for producing a molded article according to the present embodiment includes a step of disposing the release film 10 on an object such that one release surface (release surface of the release layer 1) of the release film 10 is on the object side, and a step of hot stamping the object on which the release film 10 is disposed, wherein the surface of the object on which the release film 10 is disposed is formed of a material containing a thermosetting resin in the step of disposing the release film 10.

After the step of disposing the release film 10, a step of disposing a material on the release surface of the 2 nd release layer of the release film 10 (release surface of the release layer 2) may be further included.

In addition, the conditions of hot stamping can be known methods.

An example of a method for manufacturing a molded product according to the present embodiment will be described, for example, when the molded product is used for manufacturing a flexible printed circuit board.

In this case, when the cover film is hot-stamped to adhere to the circuit in order to protect the circuit formed on the flexible film, the release film 10 is used between the cover layer and the press machine.

Specifically, the release film 10 is used in, for example, a cover layer press lamination step which is one of the steps of manufacturing a flexible printed wiring board. More specifically, when the cover film is adhered to the circuit exposure film, the release film 10 is disposed so as to cover the cover film, the cover film is brought into close contact with the concave-convex portion of the circuit pattern, and the circuit exposure film and the cover film are heated and pressed together by a press machine.

In this case, in order to improve cushioning properties, paper, rubber, a fluororesin sheet, cellophane, or the like, or a material formed by combining these may be inserted between the release film 10 and the press machine and then heated and pressurized.

The release film 10 of the present embodiment can also be used to produce the molded article described above by the following method.

First, the 1 st release surface of the release layer 1 of the release film 10 according to the present embodiment is disposed on the surface of an object formed of a material containing a thermosetting resin. Next, paper, rubber, a fluororesin sheet, cellophane, or the like, or a material combining these, is disposed on the 2 nd release surface of the release layer 2 of the release film 10. Then, the object provided with the release film 10 is subjected to press processing in a die. Here, the thermosetting resin may be in a semi-cured state or a cured state, and the effect of the mold release film 10 becomes more remarkable in the semi-cured state. Particularly in the case where the thermosetting resin is a resin composition containing an epoxy resin, it is preferable that the epoxy resin is in an intermediate stage of the curing reaction, that is, in a B-stage state.

The release film according to the present embodiment can be applied to known methods such as a roll-to-roll method, a rapid press method, and a multi-stage press method. Among them, the use of the roll-to-roll method or the rapid press method makes it easy to obtain high peelability and good follow-up property by the release film 10.

In the roll-to-roll system, the press system is automated to automatically transfer the release film or FPC. Always heated to a predetermined temperature and peeled off immediately after hot stamping. The rapid press method is a method in which a press molding machine having buffer pieces mounted on top and bottom of a press plate is heated to a predetermined temperature all the time, and objects such as FPCs are assembled to the press molding machine with one surface to perform hot press. The multi-stage press method is a method in which a plurality of FPCs are stacked and assembled via a buffer sheet on a press molding machine in the vicinity of room temperature, and then the FPCs are pressed and heated, and then subjected to a cooling process to perform hot press.

< Method for recycling Release film >

Next, a method for recycling the release film 10 according to the present embodiment will be described.

The method for recycling the release film 10 according to the present embodiment includes a step of pulverizing the release film used in the method for producing a molded article described above and processing the pulverized release film into a material for the release film, and a step of forming a 2 nd release film using the material for the release film.

The used release film 10 can be crushed by a known method. For example, the used release film 10 is cleaned or removed by a known method, and then cut/crushed to 1 to 50mm using a known crusher. The used release film 10 may be either sheet-like or roll-like.

Next, the crushed used release film 10 is heated and melted by a known method to prepare a film-forming raw material. In this case, when foreign matter or the like is present, the foreign matter is removed by using a filter or the like.

Thereafter, the obtained film raw material can be used to reproduce the 2 nd release film by a known method such as a coextrusion method, an extrusion lamination method, a dry lamination method, or an inflation method in the same manner as the method for producing the release film 10.

From the viewpoint of obtaining processability and preservability, the film raw material may contain known additives such as antioxidants, slip agents, antiblocking agents, antistatic agents, colorants such as dyes and pigments, stabilizers, and the like.

The 2 nd release film preferably has a2 nd release layer and a2 nd buffer layer formed on the 2 nd release layer. The 2 nd buffer layer is preferably formed using the above-described film raw material. This can improve the releasability of the 2 nd release film. Examples of the application of the release film 2 include application disposed between a mold and a reinforcing plate when attaching the reinforcing plate and the like.

As the 2 nd release layer, the same resin composition as that described in the release layer 1 can be used, and particles may be contained in the same manner as in the release layer 1.

The 2 nd release film may further have a 2 nd secondary release layer on the surface opposite to the 2 nd release film. As the 2 nd release layer, the same resin composition as that described in the release layer 2 can be used, and particles may be contained in the same manner as in the release layer 2. The thickness of the release film 2, the materials of the release layers and the buffer layer 2, and the like can be known thicknesses and materials.

< Method for producing Release film No. 2>

The method for producing a2 nd release film according to the present embodiment includes a step of pulverizing the release film 10 used in the method for producing a molded article, and a step of forming a2 nd release film using the film raw material.

The 2 nd release film of the present embodiment includes a 2 nd release layer and a 2 nd buffer layer formed on the 2 nd release layer, and the 2 nd buffer layer is preferably a layer formed from the film raw material.

The method of forming the film can be a known method, similar to the method of manufacturing the release film 10.

The embodiments of the present invention have been described above, but the embodiments are illustrative of the present invention, and various configurations other than the above can be adopted.

In the present embodiment, the release film 10 has been described as having a laminated structure in which the release layer 1, the buffer layer 3, and the release layer 2 are laminated in this order in the thickness direction, but the present invention is not limited thereto.

For example, the release film may have a structure of 4 layers or more such as 4 layers and 5 layers including an adhesive layer and a gas barrier layer. In this case, the adhesive layer and the gas barrier layer are not particularly limited, and known adhesive layers and gas barrier layers can be used.

The embodiments of the present invention have been described above, but the embodiments are illustrative of the present invention, and various configurations other than the above can be adopted. The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within a range that can achieve the object of the present invention are also included in the present invention.

Examples

The present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

< Release film >

Each release film having the structure shown in table 1 was prepared as follows.

(1) Raw materials of release layer 1,2

Polybutylene terephthalate (PBT) under the trade name 1100-211S (manufactured by vinca resin Co., ltd. (CHANG CHUN PLASTICS)).

Polybutylene terephthalate-polytetramethylene glycol copolymer (PBT-PTMG copolymer) under the trade name 5510S (Mitsubishi engineering plastics Co., ltd. (Mitsubishi Engineering-Plastics Corporation), MFR33cm ²/10 min (260 ℃ C., 2.16 kg)).

Polymethylpentene (TPX) under the trade designation RT31 (Mitsui Chemicals, inc.).

(2) Raw material of buffer layer 3

Low Density Polyethylene (LDPE) product number R500 (UBE-MARUZEN POLYETHYLENE, manufactured by Yu Bolus polyethylene Co., ltd.).

Ethylene-methyl acrylate copolymer (EMA) commercially available under the trade designation EB140F (manufactured by Japanese polyethylene Co., ltd. (Japan Polyethylene Corporation)).

Polyethylene terephthalate glycol (PETG) under the trade designation S2008 (SK chem (SK CHEMICALS)).

Polycyclohexanedimethanol terephthalate (PCTG) under the trade designation DN011 (manufactured by Isman chemical company (EASTMAN CHEMICAL)).

Polypropylene (PP) product number E111G (manufactured by Prime polymer co., ltd.).

(3) Production of release film

The raw materials of the release layer 1, the release layer 2, and the buffer layer 3 shown in table 1 were supplied to 3 extruders, and were co-extruded through a multi-manifold die, thereby producing a release film in which the release layer 1, the buffer layer 3, and the release layer 2 were laminated in this order.

At this time, the thicknesses of the layers and the arithmetic average roughness Ra of the release surface were prepared so as to have the values shown in table 1. The temperature of the 1 st roll at the time of film production was set to 90 ℃, and the arithmetic average roughness Ra of the release surface was adjusted by using at least either the 1 st roll or the contact roll.

< Measurement of Release film >

Using the obtained release film, the following measurement/evaluation was performed. The results are shown in Table 1.

(1) For the requirements 1-4

The storage elastic modulus (MPa) and the loss elastic modulus (MPa) of each release film were measured under the following measurement conditions. Thereafter, the hot stamping treatment was performed under the following hot stamping conditions, and the storage elastic modulus (MPa) and the loss elastic modulus (MPa) of the release film after that were measured under the same conditions as those before the hot stamping treatment. The storage elastic modulus under the condition of 70 ℃ was set to A1, the storage elastic modulus under the condition of 70 ℃ after the hot stamping was set to A2, the loss elastic modulus under the condition of 70 ℃ was set to B1, the loss elastic modulus under the condition of 70 ℃ after the hot stamping was set to B2, the storage elastic modulus under the condition of 100 ℃ was set to C1, the storage elastic modulus under the condition of 100 ℃ after the hot stamping was set to C2, the storage elastic modulus under the condition of 150 ℃ was set to D1, the storage elastic modulus under the condition of 150 ℃ after the hot stamping was set to D2, and the respective values are shown in table 1.

[ Measurement conditions ]

Device A viscoelasticity measuring device DMA7100 (manufactured by Hitachi Corporation (HITACHI HIGH-Tech Corporation)).

The starting temperature is 25 ℃.

The end temperature is 230 ℃.

The temperature rising speed is 5 ℃ per minute.

Sampling for 3sec.

Measurement mode: stretch.

The frequency is 1Hz.

The strain amplitude was 10. Mu.m.

Minimum tension 50mN.

Tension gain 1.2.

The sample length was 20mm.

Sample width 4mm.

The measurement direction is the MD direction.

[ Hot stamping conditions ]

Apparatus RR Q-CURE 100 ton continuous laminator (TRM Co., ltd.) roll-to-roll (RtoR) press.

Temperature 175 ℃.

Time 150sec.

The pressure was 110kg/cm ².

(Instead of the surface pressure to the membrane, the device set pressure)

(2) Observation of sea-island structure

Using a Scanning Electron Microscope (SEM), a cross section of the release film parallel to the TD direction was observed, and the presence or absence of the island structure was determined. When island structures having a diameter of 0.1 μm or more were confirmed, it was determined that sea-island structures were present.

(3) Arithmetic average roughness Ra of surface of release layer side of release film

The measurement was carried out in accordance with JIS B0601:1994.

< Evaluation of Release film >

The release films were evaluated as follows. The results are shown in Table 1.

(1) Roll-to-roll mode

As a roll-to-roll system, an RR Q-CURE 100 ton continuous laminator (TRM co., ltd.) press machine, roll-to-roll (RtoR) was used. As shown in fig. 2, a long glass cloth 40, a release film 41 (width 270 mm), and a copper-clad laminate for flexible wiring board 42 (test piece) were wound out from a roll, laminated between hot plates 43, and then thermally pressure-bonded, and then, the release film 41 was conveyed in the direction of a release rod 44 from the outlet of the hot plate 43, and was peeled off from the copper-clad laminate for flexible wiring board 42 (test piece) by passing the release film 41 through the release rod 44, and the following releasability 1 and followability 1 were evaluated.

Mold release 1:

First, a copper-clad laminate for a flexible wiring board on which a harness having a roll width of 250mm and an L/S of 100/100 μm was formed was prepared and used as a test piece to carry out a severe test.

Next, the roll-to-roll press machine described above was used for evaluation. In this case, between the hot plates, the release film was disposed on both surfaces of the test piece so that the release surface on the 1 st release layer side of the release film faced the test piece, and the glass cloth was disposed so as to sandwich the release film on the outer side. Then, after hot stamping was performed at a temperature of 175℃for 150sec and a pressure of 110kg/cm ², the product was transferred in the direction of a knock-out bar at a transfer rate of 300mm/s, a feed amount of 500mm and a distance from the hot plate outlet to the knock-out bar of 50mm, thereby obtaining a molded product.

At this time, the releasability of the release film was evaluated based on the following criteria.

And (3) demolding at the position near the front of the demolding rod by more than 10 mm.

Demolding at the demolding rod or near the front of less than 10 mm.

And X, winding the release film on a release rod or breaking the release film.

Follows ability 1:

First, a copper-clad laminate for a flexible wiring board, on which a harness having a roll width of 250mm and an L/S of 100/100 μm was formed, was prepared. Then, a plurality of 1mm square openings were formed in a cover layer (CMA 0525) made by the glossy manufacturer (Arisawa Manufacturing co., ltd.) and the adhesive-coated side of the cover layer was bonded to both sides of a copper-clad laminate for flexible wiring boards, thereby producing temporary-fixing test pieces.

Next, the roll-to-roll press machine described above was used for evaluation. In this case, between the hot plates, the release film was disposed on both surfaces of the test piece so that the release surface on the 1 st release layer side of the release film faced the test piece, and the glass cloth was disposed so as to sandwich the release film on the outer side. Then, after hot stamping was performed at a temperature of 175℃for 150sec and a pressure of 110kg/cm ², the product was transferred in the direction of a knock-out bar at a transfer rate of 60mm/s, a feed amount of 500mm and a distance from the hot plate outlet to the knock-out bar of 200mm, thereby obtaining a molded product.

In the molded article obtained as described above, the amount of the adhesive applied to the surface of the cover layer flowing out from the outer edge portion of the opening was observed by an optical microscope in the opening formed in the cover layer, and the embeddability was evaluated based on the following criteria.

The outflow was less than 70. Mu.m.

The delta outflow is 70 μm or more and less than 100 μm.

The outflow was 100 μm or more.

(2) Quick stamping mode

As a rapid press system apparatus, HH46 LAMINATOR (rapid press machine manufactured by tetram co., ltd.) was used, and the following release property 2 and following property 2 were evaluated.

Mold release 2:

First, a copper-clad laminate for a flexible wiring board on which electric wires having an L/S of 100/100 μm were formed was prepared. Then, a plurality of 1mm square openings were formed in a cover layer (CMA 0525) made by the glossy manufacturer (Arisawa Manufacturing co., ltd.) and the adhesive-coated side of the cover layer was bonded to both sides of a copper-clad laminate (width 250mm, length 170 mm) for a flexible wiring board, thereby producing a test piece to be temporarily fixed.

Next, evaluation was performed using the rapid punch described above. In this case, the release film was disposed on both surfaces of the test piece so that the release surface on the 1 st release layer side of the release film faced the test piece. Then, a hot stamping treatment was performed under vacuum at 180 ℃ for 10 seconds and 1 minute under a vacuum condition, thereby obtaining a molded article. After the release film and the obtained molded article were taken out, the release film and the molded article were peeled off by hand so that a minute gap was formed at the end portion, and the molded article was set as a trigger for peeling off, and then allowed to stand on a work table. At this time, the releasability of the release film was evaluated based on the following criteria.

And (3) after the peeling trigger is given, demolding the whole surface of the product for less than 45 s.

After the peeling trigger is given, the entire surface is released from the mold for 45s or more and less than 90 s.

After the peeling trigger is given, the entire surface needs to be demolded for 90 seconds or more or is not demolded.

Follows ability 2

Next, evaluation was performed using the rapid punch described above. In this case, the release film was disposed on both surfaces of the test piece so that the release surface on the 1 st release layer side of the release film faced the test piece. Then, a hot stamping treatment was performed under vacuum at 180 ℃ for 10 seconds and 1 minute under a vacuum condition, thereby obtaining a molded article. In the molded article obtained as described above, the amount of the adhesive applied to the surface of the cover layer flowing out from the outer edge portion of the opening was observed by an optical microscope in the opening formed in the cover layer, and the embeddability was evaluated based on the following criteria.

The outflow was less than 70. Mu.m.

The delta outflow is 70 μm or more and less than 100 μm.

The outflow was 100 μm or more.

Recyclability of

Each release film used in the evaluation of "releasability 2" of the rapid press method (2) above was crushed and processed into a film-forming raw material. Next, a raw material for a film was used as the 2 nd buffer layer, and coextrusion was performed by a multi-manifold die, whereby a reusable release film was produced in which the release layers 1, 2 nd buffer layer and release layer 2 were laminated in this order.

A copper-clad laminate for a printed wiring board to which a clad layer is bonded was prepared. Then, as a reinforcing plate, a reinforcing plate in which a thermosetting adhesive having a thickness of 50 μm was bonded to FR4 having a thickness of 1mm was prepared, and an adhesive surface of the reinforcing plate was bonded to the prepared copper-clad laminate for a printed wiring board, thereby producing a test piece.

Next, evaluation was performed using the rapid punch described above. Specifically, the reusable release film was disposed on both sides of the test piece so that the release surface on the 1 st release layer side of the reusable release film faced the test piece. Then, a hot stamping treatment was performed under vacuum at 180 ℃ for 10 seconds and 1 minute under a vacuum condition, thereby obtaining a molded article. After the reuse mold release film and the obtained molded article were taken out, the reuse mold release film and the molded article were peeled off by hand so as to form a minute gap at the end portion, and the molded article was set as a trigger for peeling off, and then allowed to stand on a work table. At this time, the releasability of the release film was evaluated based on the following criteria.

The present application claims priority based on Japanese patent application No. 2021-193217 of 11/29/2022 and Japanese patent application No. 2022-139856 of 9/2022, and the disclosures of which are incorporated herein in their entirety.

Description of the reference numerals

1, A release layer, 2, a release layer, 3, a buffer layer, 10, a release film, 40, a glass cloth, 41, a release film, 42, a copper-clad laminate for flexible wiring boards, 43, a hot plate, and 44, a release rod.

Claims

1. A release film having a laminated structure in which a release layer and a buffer layer constituting at least one release surface are laminated,

The release layer contains 30 mass% or more of a polyester resin, and the polyester resin is a resin containing a PBT-PTMG copolymer, the PBT-PTMG copolymer being a polybutylene terephthalate-polytetramethylene glycol copolymer,

The buffer layer comprises 1 or more than 2 selected from PET, PETG, PBT, PTT and PHT and 1 or more than 2 selected from vinyl copolymer, alpha-olefin polymer, alpha-olefin copolymer, PES, PPS, polymethylpentene resin, rubber component, PET is polyethylene terephthalate resin, PETG is polyethylene terephthalate resin, PBT is polybutylene terephthalate resin, PTT is polypropylene terephthalate resin, PHT is polyhexamethylene terephthalate resin, PES is polyethersulfone, PPS is polyphenylene sulfide, and the buffer layer has sea-island structure,

The release film satisfies the following requirement 1,

The requirement 1 is that when the storage elastic modulus of the release film measured by a dynamic viscoelasticity measuring device under conditions of a stretching mode, a frequency of 1Hz and a temperature rising speed of 5 ℃ per minute under conditions of 70 ℃ is set as A1, and the storage elastic modulus of the release film after being treated under conditions of 175 ℃, 120 seconds and 2MPa is set as A2, the relation that A2/A1 is not less than 1.2 is satisfied.

2. A release film having a laminated structure in which a release layer and a buffer layer constituting at least one release surface are laminated,

The release layer contains 30 mass% or more of a polyester resin, and the polyester resin is a resin containing PBT and a copolymer thereof, the PBT is polybutylene terephthalate,

The buffer layer comprises 1 or 2 selected from EMA, LDPE, EMA is ethylene-methyl acrylate copolymer, LDPE is low density polyethylene, and the buffer layer has sea-island structure,

The release film satisfies the following requirement 1,

3. The release film according to claim 1 or 2, wherein,

The release layer contains 1 or 2 or more kinds selected from PET, PETG, PTT and PHT as the polyester resin, PET is a polyethylene terephthalate resin, PETG is a polyethylene terephthalate glycol resin, PTT is a polytrimethylene terephthalate resin, and PHT is a polyhexamethylene terephthalate resin.

4. The release film according to claim 2, wherein,

The buffer layer contains 1 or more than 2 kinds selected from PET, PETG, PBT, PTT and PHT, PET is polyethylene terephthalate resin, PETG is polyethylene terephthalate glycol resin, PBT is polybutylene terephthalate resin, PTT is polytrimethylene terephthalate resin, PHT is polyhexamethylene terephthalate resin.

5. The release film according to claim 1 or 2, wherein,

The thickness of the buffer layer is 50-90% relative to the thickness of the whole release film, and the unit of the thickness is mu m.

6. The release film according to claim 1 or 2, wherein,

The release film satisfies the following requirement 2,

Condition 2 is that when the loss elastic modulus at 70 ℃ obtained by measuring the release film using a dynamic viscoelasticity measuring device under conditions of a stretching mode, a frequency of 1Hz, and a temperature rising rate of 5 ℃ per minute is set to be B1, and the loss elastic modulus after the release film is treated under conditions of 175 ℃, 120 seconds, and 2MPa is set to be B2, the relationship of B1< B2 is satisfied.

7. The release film according to claim 1 or 2, wherein,

The release film satisfies the following requirement 3,

The requirement 3 is that when the storage elastic modulus at 100 ℃ obtained by measuring the release film using a dynamic viscoelasticity measuring device under conditions of a stretching mode, a frequency of 1Hz, and a temperature rising rate of 5 ℃ per minute is C1, and the storage elastic modulus after the release film is treated under conditions of 175 ℃, 120 seconds, and 2MPa is C2, the relationship of C2/C1 of 1.3 or more is satisfied.

8. The release film according to claim 1 or 2, wherein,

The release film satisfies the following requirement 4,

9. The release film according to claim 1 or 2, wherein,

The arithmetic average roughness Ra of the release surface is 0.1-3.5 mu m.

10. The release film according to claim 1 or 2, wherein,

The thickness of the release film is 50-200 mu m.

11. The release film according to claim 1 or 2, wherein,

The release film is suitable for use in a roll-to-roll fashion.

12. The release film according to claim 1 or 2, wherein,

The release film is suitable for a rapid stamping mode.

13. A method for producing a molded article, wherein,

The method for producing the molded article comprises the following steps:

a step of disposing the release film on the object so that the one release surface of the release film according to claim 1 or 2 is on the object side, and

And a step of hot stamping the object provided with the release film.

14. The method for producing a molded article according to claim 13, wherein,

In the step of disposing the release film, a surface of the object on which the release film is disposed is formed of a material containing a thermosetting resin.

15. The method for producing a molded article according to claim 13, wherein,

The molded article is a flexible circuit board.

16. A method for recycling a release film, wherein,

The method for recycling the release film comprises the following steps:

A process for producing a molded article according to claim 13, wherein said mold release film is pulverized and processed into a raw material for a mold release film, and

And a step of forming a2 nd release film using the material for release film.

17. The method for recycling a mold release film according to claim 16, wherein,

The 2 nd release film has a2 nd release layer and a2 nd buffer layer formed on the 2 nd release layer,

The 2 nd buffer layer is formed from the release film raw material.

18. A method for producing a release film of item 2, wherein,

The method for manufacturing the 2 nd release film comprises the following steps:

a process for producing a molded article according to claim 13, wherein said mold release film is pulverized and processed into a film-forming raw material, and

And a step of forming a 2 nd release film using the film raw material.

19. The method for producing a release film according to claim 18, wherein,

The 2 nd buffer layer is formed from the film raw material.