CN114080866B

CN114080866B - Release film and method for producing molded article

Info

Publication number: CN114080866B
Application number: CN202180002970.3A
Authority: CN
Inventors: 榎本阳介
Original assignee: Sumitomo Bakelite Co Ltd
Current assignee: Sumitomo Bakelite Co Ltd
Priority date: 2020-10-21
Filing date: 2021-07-05
Publication date: 2022-09-16
Anticipated expiration: 2041-07-05
Also published as: CN114080866A

Abstract

The release film (10) of the present invention comprises a release layer (1) on at least one surface, wherein the release layer (1) comprises one or more selected from the group consisting of a polyester resin, a poly-4-methyl-1-pentene resin, a polyamide resin, and a polypropylene resin, and has a dynamic friction coefficient of 0.01 to 0.7 as measured under the following conditions. Conditions are as follows: one release film (10) was cut into a size of 6.5cm in width and 17cm in length, and was attached to a horizontal table with the release layer (1) on the upper side, and the other release film (10) was wound around a square 63cm with the release layer (1) on the outer side and with a weight of 202 g. The weight wound with the other release film was placed on one release film (10), and the friction force was measured by moving the weight horizontally at a speed of 150 mm/min in an environment of room temperature 23. + -. 1 ℃ and humidity 50. + -. 0.5% RH, and the coefficient of friction at the point moved by 5cm was taken as the coefficient of dynamic friction.

Description

Release film and method for producing molded article

Technical Field

The present invention relates to a method for producing a release film and a molded article.

Background

The release film is generally used in the production of a molded article or in the production of a laminate in which different materials are laminated. Among these, the release film is preferably used when a flexible printed circuit board (hereinafter, also referred to as "FPC") is produced by bonding a coverlay film (hereinafter, also referred to as "CL film") to a flexible film (hereinafter, also referred to as "circuit exposure film") having exposed circuits through an adhesive by hot pressing. Specifically, it is desired to protect the surface of the flexible film or the obtained flexible printed circuit board by disposing a release film between the cover film and the heat press plate.

In recent years, with the spread of smart phones, tablet PCs, and the like, flexible circuit boards have been becoming highly functional and thin-film. Also, a manufacturing method such as a roll-to-roll (RtoR) method tends to be automated. With the automation of such a manufacturing method, wrinkles formed in the release film may be transferred to the flexible circuit board in the manufacturing process of the flexible circuit board.

With the recent miniaturization and thinning of molded articles using release films, when a tape-shaped release film is conveyed by roll-to-roll (RtoR) as described above, the problem that wrinkles generated in the release film are easily transferred to a flexible circuit board becomes remarkable. Therefore, for example, patent document 1 discloses a release film in which the ten-point average roughness Rz of the surface is 4 μm or more and 20 μm or less and the thickness of the release layer constituting the back surface is 35 μm or more (excluding the case where the ten-point average roughness Rz of the surface is 4 μm or more and 5 μm or less and the thickness of the release layer constituting the back surface is 35 μm or more and 36 μm or less).

Documents of the prior art

Patent literature

Patent document 1: japanese patent laid-open publication No. 2019-217780.

Disclosure of Invention

Technical problem to be solved by the invention

However, as a result of studies made by the present inventors, there is still room for improvement in the conventional release film described in patent document 1, in terms of suppressing the generation of wrinkles while maintaining releasability and embeddability.

Means for solving the technical problem

The present inventors have conducted intensive studies from the viewpoint of solving the problems of suppressing the generation of wrinkles and improving the yield while maintaining the releasability and embeddability of a release film, and as a result, have found that it is effective to control a release layer using a specific material by using a dynamic friction coefficient measured under a predetermined condition as an index. In other words, the present inventors have found that even in a release film using a release layer made of the same material, there are cases where the problem of suppressing the generation of wrinkles and improving the yield while maintaining the releasability and embeddability of the release film can be solved, and cases where the problem cannot be solved, and as a result of studying the difference between the two, it has been found that such a difference can be determined by using the coefficient of dynamic friction measured under a predetermined condition as an index, and have completed the present invention.

According to the present invention, there is provided a release film comprising a release layer on at least one surface, wherein the release layer comprises one or more selected from the group consisting of a polyester resin, a poly-4-methyl-1-pentene resin, a polyamide resin and a polypropylene resin, and has a dynamic friction coefficient of 0.01 to 0.7 as measured under the following conditions.

(Condition)

One of the release films was cut to a size of 6.5cm in width and 17cm in length, and was attached to a horizontal table so that the release layer was on the upper side, the other release film was wound around a weight of 202g in a square shape of 63cm so that the release layer was on the outer side, the weight around which the other release film was wound was placed on the one release film, the weight was moved horizontally at a speed of 150 mm/min in an environment of 23 ± 1 ℃ at room temperature and 50 ± 0.5% RH to measure the frictional force, and the coefficient of friction at the point moved by 5cm was set as the coefficient of dynamic friction.

Further, according to the present invention, there is provided a method for producing a molded article, comprising: disposing the release film on an object such that the one release surface of the release film is on the object side; and a step of hot-pressing the object on which the release film is disposed, 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.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a release film is provided which can suppress the occurrence of wrinkles while maintaining releasability and embeddability.

Drawings

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

Fig. 2 is a cross-sectional view schematically showing an example of the apparatus for producing a release film according to the present embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In all the drawings, the same constituent elements are denoted by the same reference numerals, and the description thereof is appropriately omitted. The shapes, size ratios, and the like of the respective components in the drawings do not necessarily correspond to actual articles.

In this specification, unless otherwise specified, the notation "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 refers to the flow Direction of the film (MD: Machine Direction), the TD Direction refers to the Direction perpendicular to the MD Direction, and the TD Direction refers to the Transverse Direction.

< mold release film >

Fig. 1 is a cross-sectional view schematically showing an example of a release film according to the present embodiment. The release film 10 of the present embodiment includes a release layer 1 on at least one surface. The release layer 1 is a layer that exerts releasability to a subject after heating and pressing with the release film 10.

The release film 10 of the present embodiment has a dynamic friction coefficient of 0.01 to 0.7 as measured under the following condition a.

(Condition a)

One release film 10 was cut into a size of 6.5cm in width and 17cm in length, attached to a horizontal platform with the release layer 1 on the upper side, and the other release film 10 was wound around a 63cm square weight of 202g with the release layer 1 on the outer side. The weight wound with the other release film 10 was placed on one release film 10, and the friction force was measured by moving the weight horizontally at a speed of 150 mm/min in an environment of room temperature 23. + -. 1 ℃ and humidity 50. + -. 0.5% RH, and the friction coefficient at the point moved by 5cm was defined as the dynamic friction coefficient.

The number of measurements was 3, and the average value was used as the coefficient of dynamic friction.

In the release film 10 of the present embodiment, the coefficient of dynamic friction is 0.01 or more, preferably 0.1 or more, and more preferably 0.2 or more. By setting the coefficient of dynamic friction to be equal to or higher than the lower limit value, it is possible to suppress the occurrence of problems such as the occurrence of a slip during transportation or a slip during winding/unwinding, which may occur due to excessive slip.

On the other hand, in the release film 10 of the present embodiment, the coefficient of dynamic friction is 0.7 or less, preferably 0.65 or less, and more preferably 0.6 or less. By setting the coefficient of dynamic friction to be equal to or less than the upper limit value, the slidability is improved, wrinkles are suppressed from occurring during conveyance, and the yield is easily improved.

The release film 10 of the present embodiment preferably satisfies the following condition b.

(Condition b)

Tan delta at 50 ℃ when a release film 10 having a thickness of 100 μm, a width of 4mm and a length of 20mm formed in the MD direction was measured in a stretching mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min with a dynamic viscoelasticity measuring apparatus ₅₀ 0.05 to 0.2 and tan delta at 175 ℃ or lower ₁₇₅ Is 0.15 to 0.25 inclusive.

In the release film 10 of the present embodiment, tan δ is the same as that of the release film ₅₀ Is 0.05 to 0.2, preferably 0.08 to 0.15. By mixing the tan delta ₅₀ If the lower limit value is not less than the above-described lower limit value, the workability during conveyance and the like can be improved, and the occurrence of wrinkles can be suppressed. On the other hand, by adding the tan. delta. to the solution ₅₀ If the upper limit value is less than or equal to the above-described upper limit value, the mold release film is made to have an appropriate hardness, thereby suppressing the occurrence of wrinkles during conveyance and easily improving the yield.

In the release film 10 of the present embodiment, the tan δ is ₁₇₅ Is 0.15 to 0.25 inclusive, preferably 0.20 to 0.25 inclusive. By mixing the tan delta ₁₇₅ When the lower limit value is not less than the above-described lower limit value, a favorable releasability can be obtained while maintaining a suitable elasticity under the use temperature condition of the release film.On the other hand, by adding the tan. delta. to the solution ₁₇₅ If the release film is used, the release film has appropriate hardness, and thus wrinkles can be easily and effectively suppressed.

The release film 10 of the present embodiment preferably satisfies the following condition c.

(Condition c)

When a release film 10 having a thickness of 100 μm, a width of 4mm and a length of 20mm formed in the MD direction was measured in a tensile mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min with a dynamic viscoelasticity measuring apparatus, the storage modulus at 175 ℃ was 10MPa or more and 40MPa or less.

In the release film 10 of the present embodiment, the storage modulus is 10MPa to 40MPa, and preferably 15MPa to 37 MPa. By setting the storage modulus to the lower limit or more, good heat resistance can be obtained at the time of hot press molding, and the mold release property can be improved. On the other hand, by setting the storage modulus to the upper limit value or less, the release film 10 has appropriate hardness, and thus occurrence of wrinkles during transportation is suppressed, yield is easily improved, and good embeddability can be obtained.

The release film 10 of the present embodiment preferably satisfies the following condition d.

(Condition d)

A release film 10 having a thickness of 100 μm, a width of 4mm and a length of 20mm formed in the MD direction was measured in a tensile mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min by a dynamic viscoelasticity measuring apparatus, and the loss modulus at 175 ℃ was 2.0MPa to 10 MPa.

In the release film 10 of the present embodiment, the loss modulus is 2.0MPa or more and 10MPa or less, and preferably 3.0MPa or more and 5.5MPa or less. By setting the loss modulus to the lower limit or more, the workability at the time of conveyance or the like is improved to suppress the occurrence of wrinkles, and the heat resistance is improved, and a good mold release property can be obtained. On the other hand, by setting the loss modulus to the upper limit value or less, the mold release film is made to have an appropriate hardness, thereby suppressing the occurrence of wrinkles during conveyance and easily improving the yield.

The dynamic viscoelasticity measuring apparatus is not particularly limited, and DMA7100 (manufactured by Hitachi High-Tech Science Corporation), DMS7100 (manufactured by SSI NanoTechnology Inc.), DMS6100 (manufactured by SSI NanoTechnology Inc.) and the like can be used.

In the present embodiment, it is important that the release film 10 satisfying the above conditions a to d is controlled by appropriately combining known techniques, and can be obtained by a manufacturing method different from a conventional manufacturing method as described later. That is, the release film 10 satisfying the above conditions a to d can be obtained only by combining known techniques described below and performing a manufacturing method different from the conventional manufacturing method.

(i) Selection of the Material of the Release layer 1

(ii) Temperature control in the process of producing release film 10 (release layer 1)

(iii) Embossing of mold release film 0 (mold release layer 1)

The details of each of the above (i) to (iii) will be described later.

The thickness of the entire release film 10 of the present embodiment is preferably 50 μm or more and 200 μm or less, more preferably 70 μm or more and 180 μm or less, and still more preferably 90 μm or more and 150 μm or less.

By setting the thickness of the entire release film 10 to be equal to or greater than the lower limit value, the workability of the release film 10 is improved, and the occurrence of wrinkles is easily suppressed.

On the other hand, by setting the thickness of the entire release film 10 to the upper limit or less, the balance between the releasability and the embeddability can be maintained.

In the case where the release film 10 is composed of only the release layer 1, the thickness of the entire release film 10 is the same as the thickness of the release layer 1 described later.

[ Release layer ]

The material of the release layer 1 may be one or two or more selected from polyester resins, poly-4-methyl-1-pentene resins, polyamide resins, and polypropylene resins. This makes it possible to obtain the release film 10 satisfying the conditions a to d.

Examples of the polyester resin include polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), polytrimethylene terephthalate resin (PTT), polyhexamethylene terephthalate resin (PHT), and polyethylene naphthalate resin (PEN).

Examples of the polyamide resin include aliphatic polyamides and aromatic polyamides. Specific examples of the aliphatic polyamide include polyamide 6, polyamide 6-6,6 copolymer, polyamide 11, polyamide 12 and the like. Specific examples of the aromatic polyamide include polyamide 61, polyamide 66/6T, polyamide 6T/6, polyamide 12/6T and the like.

Among them, polyethylene terephthalate resins, polybutylene terephthalate resins, and polyamide resins are preferable.

As the release layer 1, a stretched film can be used, and as the stretching, a known stretching method such as sequential biaxial stretching, simultaneous biaxial stretching, tubular stretching, or the like can be used for production.

The release layer 1 may contain, in addition to the above-mentioned resins, additives such as antioxidants, slip agents, releasing agents, antistatic agents, colorants such as dyes and pigments, stabilizers, fluorine resins, impact resistance imparting agents such as silicone rubbers, and inorganic fillers such as titanium oxide, calcium carbonate, and talc.

The surface roughness Rz of the release surface 3 of the release layer 1 in the MD direction is preferably 2 to 20 μm, more preferably 5 to 20 μm, and still more preferably 8 to 20 μm.

By setting the surface roughness Rz to the lower limit value or more, the slidability during conveyance is improved and the occurrence of wrinkles is easily suppressed. On the other hand, by setting the surface roughness Rz to the upper limit value or less, the balance between the mold release property and the embedding property is improved, and the transfer of the uneven shape of the mold release film to the FPC can be suppressed.

The surface of the release layer 1 to be the release surface 3 is a surface which comes into contact with an object when a release film is used.

The method for controlling the surface roughness can be adjusted by the following known methods: in the step of producing the release film 10 (or release layer 1), an embossed pattern is transferred to the film using a roll subjected to embossing, or particles or the like are blended into the material of the release layer 1.

The surface roughness Rz is measured according to JIS B06011994.

The thickness of the release layer 1 is preferably 5 to 50% of the thickness of the entire release film 10, and may be 100%.

By setting the thickness of the release layer 1 to the lower limit or more, the rigidity of the release film 10 is increased, and generation of wrinkles due to excessive deformation is easily suppressed.

The thickness of the release layer 1 is appropriately set according to the purpose, and may be, for example, 3 μm or more, or 5 μm or more, or 60 μm or less, or 50 μm or less.

[ multilayer Structure ]

The release film 10 in the present embodiment may have the release layer 1 on at least one surface, and may be constituted only by the release layer 1, or may have a multilayer structure including layers having other functions. The release layer 1 may be a single layer or two or more layers.

When the number of the release layers is two or more, the respective release layers may be formed of the same material or different materials. Also, the plurality of releasing layers 1 may have different thicknesses from each other.

Specifically, for example, a release film having different release layers on both surfaces of the release film may be used. When the release film in this case is used, the side having the surface in contact with the object may be referred to as a release layer, and the other surface may be referred to as a sub-release layer. By having the secondary release layer, the releasability from the hot plate when hot-pressed by a press is improved, and the productivity in producing a laminate such as a molded body or an FPC can be improved. Further, for example, the release film may further have a buffer layer in contact with the release layer. The release film may have a three-layer structure in which a release layer, a cushion layer, and a sub-release layer are laminated in this order.

Examples of the layer having another function include an adhesive layer and a gas barrier layer. The adhesive layer and the gas barrier layer are not particularly limited, and a known gas barrier layer can be used.

The buffer layer will be described in detail below.

[ buffer layer ]

The cushion layer gives cushioning properties to the entire release film by using a resin having flexibility. Thus, when the release film is used, heat and pressure from the press hot plate are easily and uniformly transmitted to the adherend, and the adhesiveness and embeddability of the release film to the adherend can be further improved.

Examples of the resin material forming the buffer layer include an α -olefin polymer such as polyethylene or polypropylene, an α -olefin copolymer having a polymer component such as ethylene, propylene, butene, pentene, hexene, or methylpentene, and an engineering plastic resin such as polyether sulfone or polyphenylene sulfide. These may be used alone or in combination of two or more. Among them, an α -olefin copolymer is preferable. Examples of the α -olefin copolymer include a copolymer of an α -olefin such as ethylene and a (meth) acrylate, a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and (meth) acrylic acid, and a partially crosslinked product thereof. In addition, from the viewpoint of obtaining a good buffer function, it is preferable to use a mixture of an α -olefin- (meth) acrylate copolymer such as ethylene alone, a mixture of polybutylene terephthalate and polyethylene terephthalate copolymerized with 1,4 cyclohexanedimethanol, and a mixture of an α -olefin polymer and an α -olefin- (meth) acrylate copolymer such as ethylene. For example, a mixture of ethylene and an ethylene-methyl methacrylate copolymer (EMMA), a mixture of polypropylene (PP) and an ethylene-methyl methacrylate copolymer (EMMA), a mixture of polybutylene terephthalate (PBT), polypropylene (PP) and an ethylene-methyl methacrylate copolymer (EMMA), and the like are more preferable.

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

The cushion layer may contain an antioxidant, a slip agent, a release agent, an antistatic agent, a coloring agent such as a dye or a pigment, an additive such as a stabilizer, an impact resistance imparting agent such as a fluororesin or a silicone rubber, and an inorganic filler such as titanium oxide, calcium carbonate or talc.

Examples of the method for forming the buffer layer include known methods such as air-cooling, water-cooling inflation extrusion, and T-die extrusion.

The thickness of the buffer layer is appropriately set according to the purpose, but is preferably 30 to 95%, more preferably 50 to 90%, relative to the total thickness of the release film.

The thickness of the buffer layer is, for example, preferably 20 μm to 130 μm, more preferably 40 μm to 120 μm, and still more preferably 50 μm to 110 μm. When the thickness of the cushion layer is not less than the lower limit, the cushion property of the release film can be suppressed from being lowered. When the thickness of the cushion layer is equal to or less than the upper limit value, the decrease in mold release properties can be suppressed.

< method for producing mold release film >

The method for producing the release film of the present embodiment is not particularly limited, and for example, the release layer and the buffer layer are produced separately, or the release layer, the buffer layer, and the sub-release layer are produced separately, and then bonded together by a laminator or the like to obtain a release film, and the release film may be bonded directly or via an adhesive layer. Alternatively, the release film can be obtained, for example, by the following method: the release layer and the buffer layer, or the release layer, the buffer layer and the sub-release layer are formed into a film by an air-cooling or water-cooling co-extrusion inflation method or a co-extrusion T-die method. Among them, a method of forming a film by a co-extrusion T-die method is preferable in terms of excellent control of the thickness of each layer.

Hereinafter, a method for producing the release film (release layer) by the T-die extrusion method will be described in the case where the release film is composed of only the release layer.

As shown in fig. 2, the melt M of the release layer raw material melted by heating is guided to the 1 st roller 530 after passing through the mold 510 and molded into a film shape, and is fixed to the 1 st roller 530 by the contact roller 520, and is cooled by the 1 st roller 530 until being released from the 1 st roller 530, thereby becoming the release film 200. Then, the release film 200 is conveyed from the 2 nd roll 540 to the downstream side in the film conveying direction (refer to an arrow in fig. 1), and is finally wound on a winding roll (not shown).

In this case, it is important that the temperature of the 1 st roller 530 is 60 to 110 ℃, the temperature of the touch roller 520 is 20 to 50 ℃, and the temperature of the 2 nd roller 540 is 60 to 90 ℃. By setting the temperature of each roller in the above range, the film-shaped melt M is gradually cooled, and therefore the crystallinity of the release film 200 can be improved. That is, as a result of the improved crystallinity of the release layer, the dynamic friction coefficient is easily reduced, and the heat resistance is easily improved, so that the elastic modulus is easily improved. As a result, appropriate elasticity can be obtained, and the storage modulus, loss modulus, and tan δ under the above conditions b to d can be controlled. In addition, the winding speed is preferably 20 to 60m/s in order to stably obtain the slow cooling effect.

Further, by using the contact roller 520 having an embossed surface, unevenness is imparted to the film surface passing through the die 510. On the other hand, the surface roughness can be reduced by using an air knife without using a contact roller.

As a result, the surface state of the release layer of the finally obtained release film is controlled, whereby a release film satisfying the above conditions a to d can be obtained.

In addition, although the case where the release film is composed of only the release layer has been described above, the release film may have a multilayer structure having layers other than the release layer. That is, the release film satisfying the conditions a to d can be obtained by controlling the temperature of each roller during the process of producing the release layer and by appropriately performing the embossing on the release layer.

< method of Using mold Release film >

The release film of the present embodiment can be used, for example, in the production of a flexible printed circuit board. In this case, in order to protect the circuit formed on the flexible film, when the cover film is hot-pressed and adhered to the circuit, the release film is used between the cover layer and the punch.

Specifically, the release film is used in, for example, a coverlay press lamination process which is one of the processes for manufacturing a flexible printed wiring board. More specifically, when the cover film is bonded to the circuit-exposed film, the release film is disposed so as to cover the cover film, and is heated and pressed by a pressing machine together with the circuit-exposed film and the cover film, in order to adhere the cover film to the uneven portions of the circuit pattern. In this case, in order to improve the cushioning property, paper, rubber, a fluororesin sheet, cellophane, or the like, or a combination thereof may be inserted between the release film and the press machine, and then heated and pressed. With regard to the punch, after the sample was set on a hot plate heated to 175 ℃, pressurization was started, the temperature was maintained for 2 minutes, and then pressurization was terminated and the sample was taken out/unloaded. The pressing pressure at this time can be suitably adjusted to 5 to 15 MPa.

The release film of the present embodiment can be used by the following method.

First, the surface of the release layer of the release film according to the present embodiment is disposed on the surface of an object made of a material containing a thermosetting resin. Then, the object on which the release film is disposed is subjected to a pressing process in the mold. Here, the thermosetting resin may be in a semi-cured state or a cured state, but if in a semi-cured state, the action and effect of the release film are more remarkable. In particular, in the case where the thermosetting resin is a resin composition containing an epoxy resin, the epoxy resin is preferably in an intermediate stage of a curing reaction, i.e., a B-stage state.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than these can be adopted. The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within a range in which the object of the present invention can be achieved are included in the present invention.

[ examples ]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto.

[ preparation of raw Material ]

As raw materials for producing the release film, the following materials were prepared, respectively.

(thermoplastic resin Material)

Poly 4-methyl-1-pentene resin I (TPX, manufactured by Mitsui Chemicals, Inc.)

Poly 4-methyl-1-pentene resin II ("RT 18", manufactured by TPX, Mitsui Chemicals, Inc.)

Polybutylene terephthalate resin I (PBT, manufactured by Catharan petrochemicals Co., Ltd., "1100-630S")

Polybutylene terephthalate resin II (PBT, manufactured by Catharan petrochemicals Co., Ltd., "1100-211H")

Polybutylene terephthalate resin III (PBT, manufactured by Mitsubishi Engineering-Plastics Corporation), "NOVADURAN, 5505S")

Low-density POLYETHYLENE (LDPE, Yu Tong POLYETHYLENE of UBE-MARUZEN POLYETHYLENE), "R300A")

Polypropylene (PP, manufactured by Sumitomo Chemical Co., Ltd., "FH 1016")

Ethylene-vinyl acetate copolymer (manufactured by EVA, Mitsui Polymer Chemicals, Inc., "EVAFLEX V5961")

< example 1 >

First, compositions comprising poly-4-methyl-1-pentene resin I (DX820) were prepared as the 1 st thermoplastic resin composition and the 2 nd thermoplastic resin composition, respectively. As the 3 rd thermoplastic resin composition, a composition comprising 50 parts by weight of low density polyethylene (R300A), 30 parts by weight of polypropylene (FH1016), and I20 parts by weight of poly-4-methyl-1-pentene resin was prepared.

Next, using the 1 st thermoplastic resin composition, the 3 rd thermoplastic resin composition and the 2 nd thermoplastic resin composition, the materials were laminated in a T-die of an extruder to form a molten resin laminate, and then cooled and solidified to form a laminate in which a 1 st release layer composed of the 1 st thermoplastic resin composition, a cushion layer composed of the 3 rd thermoplastic resin composition and a 2 nd release layer composed of the 2 nd thermoplastic resin composition were laminated in this order, thereby obtaining a release film.

In the production of the release film, the production apparatus shown in fig. 2 was used, and the temperature of the contact roll 520 subjected to embossing was set to 50 ℃, the temperature of the 1 st roll 530 was set to 110 ℃, and the temperature of the 2 nd roll 540 was set to 60 ℃. The winding speed was set at 20 m/s.

In the obtained release film, the average thickness of the 1 st release layer was 25 μm, the average thickness of the buffer layer was 70 μm, and the average thickness of the 2 nd release layer was 25 μm.

< example 2 >

First, compositions comprising poly-4-methyl-1-pentene resin II (RT18) were prepared as the 1 st thermoplastic resin composition and the 2 nd thermoplastic resin composition, respectively. Further, as the 3 rd thermoplastic resin composition, a composition comprising 40 parts by weight of an ethylene-vinyl acetate copolymer (V5921), 30 parts by weight of polypropylene (FH1016), and 30 parts by weight of a poly-4-methyl-1-pentene resin I was prepared.

In the production of the release film, the production apparatus shown in fig. 2 was used, and the temperature of the touch roll 520 was 50 ℃, the temperature of the 1 st roll 530 was 90 ℃, and the temperature of the 2 nd roll 540 was 60 ℃. The winding speed was set at 22 m/s.

In the obtained release film, the average thickness of the 1 st release layer was 10 μm, the average thickness of the buffer layer was 100 μm, and the average thickness of the 2 nd release layer was 10 μm.

< example 3 >

First, compositions comprising 50 parts by mass of a polybutylene terephthalate resin I (1100-630S) and 50 parts by mass of a polybutylene terephthalate resin III (5505S) were prepared as a 1 st thermoplastic resin composition and a 2 nd thermoplastic resin composition, respectively. As the 3 rd thermoplastic resin composition, a composition comprising 50 parts by weight of the ethylene-vinyl acetate copolymer (V5921), 30 parts by weight of polypropylene (FH1016), and 20 parts by weight of the polybutylene terephthalate resin I (1100-630S) was prepared.

In the production of the release film, the production apparatus shown in fig. 2 was used, and the temperature of the touch roll 520 was 50 ℃, the temperature of the 1 st roll 530 was 90 ℃, and the temperature of the 2 nd roll 540 was 60 ℃. The winding speed was set at 25 m/s.

In the obtained release film, the average thickness of the 1 st release layer was 20 μm, the average thickness of the buffer layer was 70 μm, and the average thickness of the 2 nd release layer was 20 μm.

< example 4 >

A release film was produced in the same manner as in example 1 except that compositions composed of poly-4-methyl-1-pentene resin II (RT18) were prepared as the 1 st thermoplastic resin composition and the 2 nd thermoplastic resin composition, respectively, and the take-up speed was 25 m/s.

In the obtained release film, the average thickness of the 1 st release layer was 12 μm, the average thickness of the buffer layer was 46 μm, and the average thickness of the 2 nd release layer was 12 μm.

< comparative example 1 >

A release film was produced in the same manner as in example 1, except that the contact roll 520 was not used, but the film was fixed to the 1 st roll 530 by a air knife, when the film was produced using the production apparatus shown in fig. 2.

< comparative example 2 >

A release film was produced in the same manner as in example 3 except that compositions comprising polybutylene terephthalate resin II (1100-211H) were prepared as the 1 st thermoplastic resin composition and the 2 nd thermoplastic resin composition.

The following measurements and evaluations were made with respect to the release films obtained in the respective examples. The evaluation results are shown in table 1.

Further, DMS6100 (manufactured by SII NanoTechnology Inc.) was used as the dynamic viscoelasticity measuring apparatus.

[ measurement ]

(a) Coefficient of dynamic friction

One of the release films was cut into a size of 6.5cm in width and 17cm in length, and was attached to a horizontal table with the release layer on the upper side, and the other release film was wound around a 63cm square weight of 202g with the release layer on the outer side. The weight wound with the other release film was placed on the one release film, and the friction force was measured by moving the weight horizontally at a speed of 150 mm/min in an environment of room temperature 23. + -. 1 ℃ and humidity 50. + -. 0.5% RH, and the friction coefficient at the point moved by 5cm was determined. This operation was repeated 3 times, and the average value was set as the coefficient of dynamic friction.

(b)tanδ

The tan delta at 50 ℃ when the release film formed in the MD direction to have a thickness of 100 μm, a width of 4mm and a length of 20mm was measured in a stretching mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min by a dynamic viscoelasticity measuring apparatus ₅₀ Tan delta at 175 ℃ or lower ₁₇₅ 。

(c) Storage modulus

The storage modulus at 175 ℃ was determined when the release film formed in the MD direction to have a thickness of 100 μm, a width of 4mm and a length of 20mm was measured in a tensile mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min with a dynamic viscoelasticity measuring apparatus.

(d) Loss modulus

The loss modulus at 175 ℃ was determined when the release film formed in the MD direction to have a thickness of 100 μm, a width of 4mm and a length of 20mm was measured in a tensile mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min by a dynamic viscoelasticity measuring apparatus.

(surface roughness Rz)

The MD direction of the surface of the release film on the release layer side was measured according to JIS B06011994.

[ evaluation ]

(appearance drape: followability)

A test piece was prepared by temporarily fixing a cover layer having an opening so that the surface of the adhesive-coated side was in contact with the surface of an insulating substrate (FPC) on which an electric wiring having an L/S of 100/100 μm was formed. Subsequently, a release film was pressed and attached to the test piece by a roll-to-roll punch under conditions of 175 ℃, 11MPa, and 120sec, and the test piece and the release film were peeled while being conveyed at 200mm/s immediately after pressing. The test piece surface was measured according to "7.5.7.2 wrinkles" of the JPCA standard.

Very good: the wrinkle generation rate was less than 1.0%.

O: the wrinkle generation rate is 1.0% or more and less than 2.0%.

X: the wrinkle generation rate is 2.0% or more.

(embeddability: adhesive outflow)

First, a 1mm square opening was formed in a cover layer (CM type) manufactured by daigawa Manufacturing co. Next, a test piece was prepared in which a cover layer having the opening was temporarily fixed so that the surface on the side to which the adhesive was applied was in contact with the surface of the copper-clad laminate for a flexible wiring board. Next, the test piece was laminated on the release film such that the 1 st release surface of the 1 st release layer in the release film faced the surface of the test piece on the side having the cover layer, and then hot-pressed under vacuum at 175 ℃. In the thus obtained molded article, the shape of the adhesive applied to the surface of the cover tape that oozes out from the outer edge portion of the opening (adhesive oozing shape) was observed in the opening formed in the cover layer, and the embeddability was evaluated based on the following criteria.

Very good: the difference in unevenness of the adhesive bleeding shape was less than 70 μm.

O: the difference in unevenness of the adhesive bleeding shape is 70 μm or more and less than 100 μm.

X: the difference in unevenness of the adhesive bleeding shape is 100 μm or more.

(releasability)

A test piece was prepared by temporarily fixing a cover layer having an opening so that the surface of the adhesive-coated side was in contact with the surface of an insulating substrate (FPC) on which an electric wiring having an L/S of 100/100 μm was formed. Next, the test piece was laminated on the release film such that the 1 st release surface of the 1 st release layer in the release film faced the surface of the test piece on the side having the cover layer, and then hot-pressed under vacuum at 175 ℃.

The peel Force between the release surface and the sample was measured at a rate of about 1000 mm/min in a 180 ℃ direction using a tensile tester (Force gauge AD-4932A-50N manufactured by AIND corporation (A & D Company, Limited)). Measurement was performed immediately after the punching, and the mold release property was evaluated according to the following criteria. The evaluation results are shown in table 1.

Very good: 0.5N or less.

O: more than 0.5N and less than 1.0N.

X: 1.0N or more.

[ Table 1]

The present application claims priority based on Japanese application No. 2020 and 176577, filed on 21/10/2020, the entire disclosure of which is incorporated herein by reference.

Description of reference numerals

1: a release layer; 3: demoulding surface; 10: demolding the film; 200: demolding the film; 510: a mold; 520: a contact roller; 530: a 1 st roller; 540: and (2) a second roller.

Claims

1. A mold release film, wherein,

the release film is provided with a release layer on at least one surface,

the release layer comprises one or more than two of polyester resin, poly 4-methyl-1-pentene resin, polyamide resin and polypropylene resin,

a storage modulus at 175 ℃ of 10MPa or more and 34.1MPa or less when the release film formed in the MD direction to have a thickness of 100 μm, a width of 4mm and a length of 20mm is measured in a tensile mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min with a dynamic viscoelasticity measuring apparatus,

and a dynamic friction coefficient measured under the following conditions is 0.01 to 0.7,

conditions are as follows: one of the release films was cut to a size of 6.5cm in width and 17cm in length, and was attached to a horizontal table so that the release layer was on the upper side, the other release film was wound around a weight of 202g in a square shape of 63cm so that the release layer was on the outer side, the weight around which the other release film was wound was placed on the one release film, the weight was moved horizontally at a speed of 150 mm/min in an environment of 23 ± 1 ℃ at room temperature and 50 ± 0.5% RH to measure the frictional force, and the coefficient of friction at the point moved by 5cm was set as the coefficient of dynamic friction.

2. The release film of claim 1,

the surface roughness Rz of the demoulding layer is 2-20 mu m.

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

tan delta at 50 ℃ when the release film formed in the MD direction to have a thickness of 100 μm, a width of 4mm and a length of 20mm was measured in a stretching mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min with a dynamic viscoelasticity measuring apparatus ₅₀ 0.05 to 0.2 and tan delta at 175 ℃ or lower ₁₇₅ Is 0.15 to 0.25 inclusive.

4. The release film according to claim 1 or 2,

and a loss modulus at 175 ℃ of 2.0MPa or more and 10MPa or less when the release film formed in the MD direction to have a thickness of 100 μm, a width of 4mm and a length of 20mm is measured in a tensile mode at a frequency of 1Hz and a temperature rise rate of 5 ℃/min with a dynamic viscoelasticity measuring apparatus.

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

the thickness of the entire release film is 50 μm or more and 200 μm or less.

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

the method is used for manufacturing the flexible circuit substrate in a roll-to-roll mode.

7. A method for producing a molded article, comprising:

disposing the release film according to any one of claims 1 to 6 on an object such that one release surface of the release film is on the object side; and

a step of hot-pressing the object on which the release film is disposed,

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.

8. The method for producing a molded article according to claim 7,

the molded product is a flexible circuit board.