CN116490357A

CN116490357A - Release film

Info

Publication number: CN116490357A
Application number: CN202180079959.7A
Authority: CN
Inventors: 小野侑司; 中谷充晴
Original assignee: Toyobo Co Ltd
Current assignee: Toyobo Co Ltd
Priority date: 2020-12-04
Filing date: 2021-11-26
Publication date: 2023-07-25
Also published as: TWI808552B; KR20230068426A; TW202227582A; JPWO2022118755A1; WO2022118755A1

Abstract

The invention provides a release film which has light release force before and after heating and can have light release force even under the condition of high-speed peeling, and does not substantially contain organic silicon. The release film according to claim 1, wherein a release layer containing at least a long-chain alkyl group-containing acrylic resin (a) and a crosslinking agent (B) and substantially no silicone component is laminated on the base film, and a ratio a/B of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (B) of the crosslinking agent contained in the release layer satisfies formula (I): (I) a/b is more than or equal to 0.1 and less than or equal to 7.0.

Description

Release film

Technical Field

The present invention relates to release films.

Background

A release film comprising a base material such as a polyethylene film and a release layer laminated thereon is used in various applications such as a battery component, an adhesive layer protection (OCA (Optical Clear Adhesive) protection, adhesive tape protection, etc.), a percutaneous absorption type adhesive separator in the medical field, a process paper used in a process for manufacturing an electronic component such as a ceramic capacitor, and a protection of an image display component. One specific example is given: the pressure-sensitive adhesive sheet is composed of a base material and a pressure-sensitive adhesive layer, and is used as a film for a process for producing electronic components and the like. The pressure-sensitive adhesive sheet is adhered to a release film before being used as a process film. In order to improve releasability, a release agent layer is provided on the surface (contact surface with the pressure-sensitive adhesive layer) of the release film. Examples of the constituent material of the release agent layer include silicone release agents, fluorine release agents, and long-chain alkyl release agents.

The silicone release agent has excellent releasability. However, there are problems that the silicone component is easily transferred to the mold body to be removed, and that the electronic equipment is erroneously operated due to contamination by the silicone, and the like, and it is difficult to use the silicone component in an electronic component. The fluorine-based release agent has excellent releasability and heat resistance. However, the cost is high and the wettability is poor. The wettability of the long-chain alkyl-based release agent is better than that of the silicone-based release agent and the fluorine-based release agent. However, it does not necessarily have sufficient releasability.

Patent document 1 (japanese patent application laid-open No. 2010-144046) discloses a release agent comprising, as a main agent, a poly (meth) acrylate containing (a) a mono-or polyalkylene glycol (meth) acrylate unit having an alkyl or aryl terminal, and (B) an alkyl (meth) acrylate unit having an alkyl group with a carbon number of 1 to 30, as a release agent capable of preventing shrinkage when an adhesive resin is applied to the release agent and further maintaining good peeling performance derived from an adhesive resin film.

Patent document 2 (japanese patent application laid-open No. 2007-002092) discloses a release agent which comprises, as a release agent having a release property lighter than that of a release agent made of a silicone resin and having no mobility, an active ingredient obtained by crosslinking at least a prepolymer obtained by copolymerizing an alkyl (meth) acrylate and a hydroxyalkyl (meth) acrylate with an isocyanate group-containing compound.

Patent document 3 (japanese patent application laid-open No. 2014-151481) discloses a laminated polyester film, which is characterized in that a coating layer formed of a coating liquid containing a release agent and an active methylene blocked isocyanate compound is provided on at least one surface of a polyester film as a release polyester film having little deterioration in releasability due to heat at the time of processing.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2010-144046

Patent document 2: japanese patent application laid-open No. 2007002092

Patent document 3: japanese patent application laid-open No. 2014-151481

Disclosure of Invention

Problems to be solved by the invention

However, in the technique of patent document 1, a release agent having a large release force and a lighter release force is required.

In addition, the technique of patent document 2 has a problem that wettability of the release agent is insufficient. The technique of patent document 3 has a problem that the peeling force after heating is heavy, and the increase in peeling force due to heating is not sufficiently suppressed.

In addition, in the production process of electronic parts and the like, heat and pressure may be applied to the release film, and in this case, the long-chain alkyl-based release agent tends to increase in release force after heating. Further, even when high-speed peeling is performed in the manufacturing process, the peeling force tends to increase. Further, even if the release layer can be peeled off, cohesive failure occurs in the release layer, and there is a possibility that the release layer component is transferred to the object to be released.

In this way, the long-chain alkyl-based release agent has a problem that the performance as a release agent cannot be sufficiently exhibited, and improvement thereof is demanded.

The present invention is an invention for solving the above-described problems, and for example, the present invention provides a release film which has a light peeling force before and after heating, and which can have a light peeling force even in the case of high-speed peeling, and which does not substantially contain silicone.

Solution for solving the problem

The present inventors have made intensive studies to solve the above problems, and as a result, have found that the above object can be achieved by a release film having the following constitution, and have completed the present invention.

That is, the present invention includes the following configurations.

[1] The release film according to claim 1, wherein the release film comprises a substrate film and a release layer comprising at least an acrylic resin (A) containing a long-chain alkyl group and a crosslinking agent (B) and substantially no silicone component,

the ratio a/b of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (b) of the crosslinking agent contained in the release layer satisfies the formula (I):

(I)0.1≤a/b≤7.0。

[2] in one embodiment, the release layer in the release film of the present invention further comprises a release agent (C), and the ratio C/b of the weight (b) of the crosslinking agent to the weight (C) of the release agent contained in the release layer satisfies the formula (II):

(II)0.1≤c/b≤10.0。

[3] in one embodiment, the release film of the present invention has a normal peel force (PF 1) of 8000mN/50mm or less at a peel speed of 0.3m/min.

[4] In one embodiment, the release film of the present invention has a peel force (PF 2) after heating (90 ℃ for 20 hours) at a peel speed of 0.3m/min, which is 2 times or less the normal peel force (PF 1).

[5] In one embodiment, the release film of the present invention has a peel force (PF 3) after heating (90 ℃ C., 20 h) at a peel speed of 30m/min, which is 10 times or less the normal peel force (PF 1).

[6] In another aspect of the present invention, there is provided a laminated film comprising an adhesive layer laminated on at least one surface of the release film of the present invention.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there is provided a release film which has light releasability before and after heating and which can maintain light releasability even in the case of high-speed release.

Detailed Description

As a result of intensive studies, the inventors have found that a release film comprising a base film and, laminated on the base film, a release layer containing at least a long-chain alkyl group-containing acrylic resin (a) and a crosslinking agent (B) and substantially no silicone component, wherein the ratio a/B of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (B) of the crosslinking agent contained in the release layer satisfies the formula (I):

(I)0.1≤a/b≤7.0

thus, the release film has a light peeling force before and after heating, and can maintain light peeling even in the case of high-speed peeling.

The release film of the present invention comprises at least an acrylic resin (A) containing a long-chain alkyl group, a crosslinking agent (B), a release layer substantially containing no silicone component, and a base film.

(substrate film)

The release film of the present invention comprises a substrate and a release layer disposed on the surface of the substrate. When the mold body to be released is disposed on the release layer of the release film, the mold body to be released can be molded into the same shape as the base material. In addition, since the release layer and the release target are easily peeled off, the shape of the release target can be deformed and maintained as desired. The release layer may be provided on one surface or both surfaces of the substrate.

As the base material, a known base material can be used. For example, as the base material, a resin film formed of polyester such as polyethylene terephthalate and polyethylene naphthalate, polyolefin such as polypropylene, polyimide, or the like can be used. In particular, from the viewpoint of cost and productivity, a polyester film is preferable, and a polyethylene terephthalate film is more preferable.

The thickness of the base material is preferably 10 μm or more and 188 μm or less, more preferably 25 μm or more and 100 μm or less. By setting the thickness of the base material to 10 μm or more, deformation can be suppressed by heat at the time of production, processing, and molding of the base material. On the other hand, when the thickness of the base material is 188 μm or less, the amount of the base material to be discarded after use can be suppressed while satisfying the physical properties required for the base material, and the burden on the environment can be reduced.

An easy-to-adhere coating for improving adhesion may be disposed between the substrate and the release layer. Further, a coating layer for providing slipperiness, heat resistance, antistatic property, and the like may be provided on the surface of the substrate opposite to the surface on which the release layer is provided.

The area surface average roughness (Sa) of the surface of the laminated release layer of the base film used in the present invention is preferably in the range of 1 to 50nm, more preferably 2 to 30nm. The maximum protrusion height (P) of the surface of the laminated release layer of the base film used in the present invention is 2 μm or less, more preferably 1.5 μm or less. When Sa is 50nm or less and P is 2 μm or less, the thickness unevenness of the release layer can be suppressed and the smoothness of the surface of the release layer can be kept constant, and further the thickness unevenness of the release film can be reduced, and the possibility of breakage starting from a thin portion when the release film is peeled off the release film can be suppressed.

The haze of the base film used in the present invention is preferably 10% or less, more preferably 5% or less, and further preferably 3% or less. When the haze is 10% or less, the appearance inspection is easy at the time of processing such as a release film and an adhesive layer on the release film.

(Release layer)

The release layer in the present invention is a release layer containing at least a long-chain alkyl group-containing acrylic resin (a) and a crosslinking agent (B) and substantially no silicone component. For example, the release layer can be formed by curing a release layer forming composition comprising a long-chain alkyl group-containing acrylic resin (a) and a crosslinking agent (B). In one embodiment, the release layer of the present invention further comprises a release agent (C).

(adhesive)

The binder contained in the release layer of the present invention contains an acrylic resin (a) containing a long-chain alkyl group.

In addition, various polymers can be used as the binder contained in the release layer of the present invention. The release layer preferably contains a polyester resin, an alkyd resin, a polyurethane resin, an acrylic resin other than the acrylic resin (a) containing a long chain alkyl group, an epoxy resin, or the like. Further, the resin preferably has a long-chain alkyl group. Although not theoretically, by repeating the results of the experiment, it is considered that: by having a long-chain alkyl group in the binder resin, a release agent described later can be efficiently oriented on the surface of the release layer. In particular, the long-chain alkyl group-containing acrylic resin (a) according to the present invention can exhibit good wettability with respect to, for example, an adhesive composition forming an adhesive. Further, it is possible to provide a release film in which the long-chain alkyl group-containing acrylic resin (a) of the present invention has light releasability before and after heating with respect to a release object such as an adhesive formed on a release layer, and can maintain light releasability even in the case of high-speed release.

In this way, the long-chain alkyl group-containing acrylic resin (a) can contribute to releasability in addition to the function as a binder in the release layer. For example, the molecular weight of the long-chain alkyl group-containing acrylic resin (A) is preferably more than 500.

The release layer of the present invention contains the long-chain alkyl group-containing acrylic resin (a), and contains substantially no silicone component. Therefore, transfer of the silicone component to the object to be released can be suppressed, and thus, for example, contamination of the object to be released with silicone can be prevented, and for example, an operation failure of the electronic device due to the object to be released can be avoided. In the present specification, "substantially not including the silicone component" means that the silicone component is not intentionally added to the component forming the release layer. For example, in the step of producing a release layer, there is a possibility that an extremely small amount of an unexpected silicone composition is contained. In view of such a practical situation, the amount of the silicone component contained in the release layer is preferably less than 0.1 part by mass with respect to 100 parts by mass of the release layer.

The long-chain alkyl group-containing acrylic resin (a) may be, for example, an acrylic polymer obtained by copolymerizing a long-chain alkyl acrylate, a graft polymer obtained by grafting a long-chain alkyl group thereto, a terminal polymer obtained by adding a long-chain alkyl group thereto, or the like. The same manner can be adopted for the polyester resin and the like which can be contained in the matrix.

Hereinafter, the acrylic resin (a) containing a long-chain alkyl group will be described in detail as an example, but the same applies to a polyester resin or the like which may be contained in a matrix.

The long-chain alkyl group-containing acrylic resin (a) is preferably a polymer obtained by crosslinking a polymer containing an X component represented by the following formula (1) and a Y component represented by the following formula (2).

In the formula (1), R ₁ Represents (cnh2n+1) (n=an integer of 8 to 20 inclusive), R ₄ Represents H or CH ₃ 。

In formula (2), R ₂ Represents (CmH 2 mOH) (m=an integer of 1 to 10 inclusive) or H, R ₄ Represents H or CH ₃ 。

In the formula (1) representing the X component, R ₁ Is an alkyl group having 8 to 20 carbon atoms. When the carbon number n is 8 or more, the X component can exhibit good releasability, and the release layer is inhibited from exhibiting adhesiveness due to the alkyl group having a small carbon number. On the other hand, when the carbon number n is 20 or less, the flexibility of the X component can be maintained, and the wettability of the film surface of the release layer can be sufficiently ensured. The carbon number n is preferably 10 to 18, more preferably 12 to 16. In addition, R ₁ The compound may be either a linear or branched compound. R is R ₁ In the case of a linear shape, the releasability of the release layer tends to be low, and is therefore preferable.

In the formula (1) representing the X component, R ₄ Is H or CH ₃ Are suitable. As a raw material for the component X,monomers represented by the following formula (7) may be used.

In the formula (7), R ₁ Represents (cnh2n+1) (n=an integer of 8 to 20 inclusive), R ₄ Represents H or CH ₃ 。

As a raw material of the X component, specifically, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like can be used.

R in formula (2) representing Y component ₂ Wherein the carbon number m is 1 to 10. When the carbon number m is 10 or less, the crosslinking density of the release layer of the present invention can be prevented from becoming sparse, the cohesive force of the release layer itself can be suppressed from decreasing, and further the peeling force can be suppressed from becoming heavy. The carbon number m is preferably 2 to 8, more preferably 2 to 4.

In the formula (2) representing the Y component, R ₄ Is H or CH ₃ Both are preferred. As a raw material of the Y component, a monomer represented by the following formula (8) can be used.

In formula (8), R ₂ Represents (CmH 2 mOH) (m=an integer of 1 to 10 inclusive) or H, R ₄ Represents H or CH ₃ 。

As a raw material of the Y component, specifically, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and the like can be used.

(crosslinking agent)

As the crosslinking agent (B) for forming the release layer of the present invention, polyisocyanate, melamine, epoxy resin, aluminum chelate, titanium chelate, ultraviolet curable resin, or a mixture of 2 or more thereof can be used. Among them, the use of melamine is preferable because the cured film is rigid and has excellent chemical resistance and weather resistance. The crosslinking in the aluminum chelate or the titanium chelate may be undesirable depending on the application.

In the present invention, the ratio a/b of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (b) of the crosslinking agent contained in the release layer satisfies the formula (I):

(I)0.1≤a/b≤7.0。

in one embodiment, the ratio a/b of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (b) of the crosslinking agent is 0.2 to 5.0, for example, 0.2 to 4.0, or 0.2 to 2.5. When the ratio a/b of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (b) of the crosslinking agent is in the above range, the release force can be further reduced because the release layer elastic modulus is improved by crosslinking the long-chain alkyl group-containing acrylic resin (a) with the binder resin further added as needed by the crosslinking agent. In addition, since the release component which is also oriented on the surface of the release layer after heating is fixed by the crosslinking agent, the increase in the release force after heating is suppressed. When the ratio of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (b) of the crosslinking agent, a/b, is 0.1 or less, the release component of the adhesive present on the surface of the release layer becomes small, and therefore, for example, in the case of using the adhesive in the release-molded article, the release force may become heavy.

In addition, when the ratio a/b of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (b) of the crosslinking agent is 7.0 or more, the crosslinking agent becomes small, and therefore the adhesive is not sufficiently crosslinked, and the release layer strength may be insufficient, and the peel force may become large. In addition, the problem tends to be more remarkable at the time of high-speed peeling.

The melamine-based compound used in the release layer of the present invention may be any general compound, and is preferably obtained by condensing melamine with formaldehyde, and has 1 or more triazine ring and hydroxymethyl and/or alkoxymethyl groups in 1 molecule. Specifically, a methylolmelamine derivative obtained by condensing melamine with formaldehyde, and a compound etherified by a dehydration condensation reaction of methanol, ethanol, isopropanol, butanol, or the like, which is a lower alcohol, are preferable. Examples of methylolated melamine derivatives include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, and hexamethylol melamine. 1 kind may be used, or 2 or more kinds may be used.

The melamine used in the present invention may be commercially available melamine. Examples thereof include CYMEL300, CYMEL301, CYMEL303LF, CYMEL350, CYMEL370N, CYMEL771, CYMEL325, CYMEL327, CYMEL703, CYMEL712, CYMEL701, CYMEL266, CYMEL267, CYMEL285, CYMEL232, CYMEL235, CYMEL236, CYMEL238, CYMEL272, CYMEL212, CYMEL253, CYMEL254, CYMEL202, CYMEL207 (manufactured by Allnex Japan Inc.), nicalackMW-30M, nicalackMW-30, nicalackMW-30-HM, nicalackMW-390, nicalackMW-100LM, nicalackMX-750LM, nicalackMW-22, nicalackMS-21, nicalackMS-11, nicakMW-24-X, nicalackMS-001, nicalackMX-002, nicakMX-730, cakMX-9, caMX-708, nicakMX-78, nicalackMX-45, nicalackMX-35, nicalackMX-45, nicalackC-35-NicalackC.45, nicalackMX-35, nicalackC-35, nicalackMX-35. Among them, polyether-type methylated melamine resins are preferable from the viewpoints of curability at low temperature in a short time and adhesion to polyester films. As commercial products, CYMEL303LF, nicalackMW-30 and the like can be mentioned.

In the release layer of the present invention, an acid catalyst is preferably added to promote the crosslinking reaction of the melamine compound, and the release layer-forming composition is preferably cured by adding the acid catalyst to the composition and applying the composition. The acid catalyst to be used is not particularly limited, and a conventional acid catalyst can be used, but a sulfonic acid catalyst is preferably used.

As the sulfonic acid-based catalyst, for example, p-toluenesulfonic acid, xylenesulfonic acid, cumene sulfonic acid, dodecylbenzene sulfonic acid, dinonylnaphthalene sulfonic acid, trifluoromethane sulfonic acid and the like can be preferably used, and p-toluenesulfonic acid can be particularly preferably used from the viewpoint of reactivity.

The sulfonic acid-based catalyst has a higher acidity and excellent reactivity than other acid catalysts such as carboxylic acid-based catalysts, and therefore can be processed at a lower temperature in the mold release layer. Therefore, it is preferable to suppress the deterioration of the flatness and the winding appearance of the film due to heat during processing.

The sulfonic acid-based catalyst used in the present invention may be a commercially available catalyst. Examples of the commercial products include DRIER (registered trademark) 900 (p-toluenesulfonic acid, manufactured by hitachi chemical Co., ltd.), NACURE (registered trademark) DNNDSA series (dinonylnaphthalene disulfonic acid, manufactured by nana chemical Co., ltd.), DNNSA series (dinonylnaphthalene (mono) sulfonic acid, manufactured by nana chemical Co., ltd.), DDBSA series (dodecylbenzenesulfonic acid, manufactured by nana chemical Co., ltd.), and p-TSA series (p-toluenesulfonic acid, manufactured by nana chemical Co., ltd.).

(Release agent)

In one embodiment, the release layer further comprises a release agent (C). The release agent used in the present invention preferably contains a long-chain alkyl group containing no silicone, and preferably a low-molecular weight polyolefin wax, a long-chain alkyl-based additive, a higher alcohol, and the like. These structures may be linear or branched. Wherein, more than two materials can be mixed for use.

In one embodiment, the ratio c/b of the weight (b) of the crosslinking agent to the weight (c) of the releasing agent contained in the releasing layer satisfies the formula (II):

(II)0.1≤c/b≤10.0。

for example, the ratio c/b of the weight (b) of the crosslinking agent to the weight (c) of the release agent is preferably 7.0 or less, for example, 5.0 or less, as the amount of the release agent to be added in the present invention. The ratio c/b may be 0.15 or more.

By adjusting the ratio (c/b) of the release agent/crosslinking agent within this range, the release agent component segregates to the surface of the release layer, and the normal release force can be reduced. Further, since the release component which is also oriented on the surface of the release layer after heating is fixed by the crosslinking agent, the increase in the release force after heating is suppressed.

On the other hand, if the ratio of the release agent/crosslinking agent is 10.0 or more, the crosslinking agent is small, and therefore, there is a possibility that the release component cannot be retained on the surface layer of the release layer when heated, and the release force may become heavy after heating.

The mold release agent used in the present invention is preferably low in molecular weight, and the molecular weight is preferably 100 to 500. By making the molecular weight of the release agent within the above range, the release agent can be easily oriented on the surface of the release layer, and the peeling force can be reduced. On the other hand, when the molecular weight is 100 or more, the releasability of the release agent can be exhibited, and the risk of exhibiting adhesion can be suppressed. In addition, when the molecular weight is 500 or less, the decrease in solubility of the release agent can be suppressed, the decrease in planarity of the release film surface can be suppressed, and the risk of deterioration in the appearance of the obtained release film can be reduced. In the present specification, such a release agent is referred to as a low molecular weight release agent, for example.

(Low molecular weight polyolefin wax)

As the low molecular weight polyolefin wax, for example, a low molecular weight polyolefin wax such as polyethylene wax or polypropylene wax can be used.

(Long-chain alkyl-based additive)

As the long-chain alkyl-based additive, an acrylic resin (a) containing a long-chain alkyl group may be added. For example, low molecular weight additives having an alkyl chain such as PEELOIL1010 and PEELOIL1010S (both of which are manufactured by Niku oil industry Co., ltd.) may be appropriately used. The release additive is added at a proper time in an amount capable of exhibiting a predetermined release property.

(higher alcohols)

As the higher alcohol, there may be mentioned octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, eicosanol, docosanol and the like.

The release agent used in the present invention preferably contains a reactive functional group. By containing the functional group, the release agent can be immobilized on the release layer by reaction with the binder component and the crosslinking agent, and therefore, movement of the release layer before and after heating can be suppressed, and good releasability can be exhibited.

Additives such as an adhesion improving agent and an antistatic agent may be added to the release layer of the present invention as long as the effects of the present invention are not impaired. In order to improve the adhesion to the substrate, it is preferable to perform pretreatment such as anchor coating, corona treatment, plasma treatment, and atmospheric pressure plasma treatment on the surface of the polyester film before providing the release coating layer.

The thickness of the release layer is preferably 0.01 μm or more and 10 μm or less, more preferably 0.05 μm or more and 1 μm or less. If the thickness of the release layer is less than 0.01 μm, it is difficult to uniformly mold the release layer, and the release force may become unstable. On the other hand, when the thickness of the release layer exceeds 10. Mu.m, the use ratio of the reclaimed material becomes low, which is not preferable.

In the present invention, the method of forming the release coating layer is not particularly limited, and a method of spreading a coating solution in which a release resin is dissolved or dispersed on one surface of a polyester film of a substrate by coating or the like, removing a solvent by drying, and then drying by heating, heat curing, or ultraviolet curing may be used. In this case, the drying temperature at the time of solvent drying and heat curing is preferably 180℃or lower, more preferably 160℃or lower, and most preferably 140℃or lower. The heating time is preferably 30 seconds or less, more preferably 20 seconds or less, and still more preferably 10 seconds or less. In the case of 180 ℃ or lower, the flatness of the film is maintained, and the possibility of causing uneven thickness of the release layer is small, which is preferable. At 140 ℃ or less, the film can be processed without impairing the flatness of the film, and the possibility of causing uneven thickness of the release layer is further reduced, which is particularly preferred.

In the present invention, the coating liquid used in coating the release coating layer is not particularly limited, and a solvent having a boiling point of 70 ℃ or higher is preferably added. By adding a solvent having a boiling point of 70 ℃ or higher, bumping during drying can be prevented, leveling of the coating film can be achieved, and planarity of the surface of the coating film after drying can be improved. The amount of the additive is preferably about 50 to 99% by mass based on the entire coating liquid.

As the coating method of the coating liquid, any known coating method can be applied, and for example, conventionally known methods such as roll coating methods such as gravure coating method and reverse coating method, bar coating methods such as wire bar, die coating method, spray coating method, and air knife coating method can be used.

The release film obtained in the present invention preferably has a normal peel force, a peel force after heating, and a peel force at high-speed peeling after heating in the following ranges.

In one embodiment, the normal peel force (PF 1) of the release film obtained in the present invention is 8000mN/50mm or less, for example, 6000mN/50mm or more and 7500mN/50mm or less, or 6000mN/50mm or more and 7000mN/50mm or less when the peel speed is 0.3m/min.

In the above range, the normal peel force is light, and is therefore preferable. When the normal peeling force is 6000mN/50mm or more, the possibility of peeling the object to be released in the conveying step is low, and it is preferable. When the peeling force before heating is 8000mN/50mm or less, the possibility of deformation of the body to be peeled is low when peeling the body to be peeled.

The normal peel force is a normal peel force at a peel speed of 0.3m/min, and the peel force at the time of peeling off a release film, for example, an adhesive (for example, an acrylic adhesive tape (product of Ridong electric Co., ltd., no. 31B)) disposed on the release layer according to the present invention may be evaluated.

In one embodiment, the peel force (PF 2) after heating (90 ℃ C., 20 h) at a peel speed of 0.3m/min is 2 times or less the normal peel force (PF 1). When the peeling force after heating (PF 2) is 2 times or less the normal peeling force, the peeling force after heating is preferably low. The peeling force after heating (PF 2) is more preferably 1.7 times or less, and most preferably 1.5 times or less, the normal peeling force (PF 1). When the peeling force after heating is 2 times or less the normal peeling force, the body to be peeled is preferably not deformed when peeling the body to be peeled after heating. In the present invention, the peeling force (PF 2) after heating may be 6000mN/50mm or more, and the possibility of peeling the body to be released in the transfer step is preferably low.

In one embodiment, the peel force (PF 3) after heating (90 ℃ C., 20 h) at a peel speed of 30m/min is 10 times or less the normal peel force (PF 1). By having such a relationship, the high-speed peeling force after heating is low, which is preferable. The peel force (PF 3) is more preferably 7 times or less, and most preferably 5 times or less, the normal peel force (PF 1). When the peeling force (PF 3) is 10 times or less the normal peeling force (PF 1), the possibility of deformation of the body to be released is preferably low when the body to be released is peeled at a high speed after heating.

In the present invention, a laminated film can be obtained by providing an adhesive layer on at least one side of a release film. The laminated film is obtained, for example, by coating an adhesive composition on at least one surface of the release film of the present invention, drying the coated film as necessary, and forming an adhesive layer on at least one surface of a substrate. For example, the release layer may have an adhesive layer on the surface opposite to the base material.

The present invention is not limited to the pressure-sensitive adhesive sheet, and is used in various applications such as a battery constituent member, pressure-sensitive adhesive layer protection (OCA (Optical Clear Adhesive) protection, pressure-sensitive adhesive tape protection, etc.), a percutaneous absorption type adhesive separator in the medical field, a process paper used in a process for manufacturing an electronic component such as a ceramic capacitor, and protection of an image display member. The same effect is expected for the effect.

Examples

Hereinafter, the present invention will be described in more detail by using examples, but the present invention is not limited to these examples. The characteristic values used in the present invention were evaluated using the following methods.

< evaluation >

(peel force in Normal (PF 1))

An adhesive tape (31B manufactured by Nito electric Co., ltd.) was attached to the surface of the release film, and the film was pressed by a pressing roller having a wire pressure of 5kgf/mm, and then left to stand at a temperature of 22℃and a humidity of 60% for 20 hours. The release film to which the adhesive tape was attached was cut into short strips having a width of 25mm and a length of 150 mm. One end of the adhesive tape was fixed, and one end of the release film was supported, and the release film side was stretched at a speed of 300mm/min, and the T-shaped peel strength was measured. A tensile tester (AUTOGRAPAG-X, manufactured by Shimadzu corporation) was used for the measurement. The results are shown in Table 1.

(peeling force after heating (PF 2))

An adhesive tape (trade name "31B" manufactured by Nito electric Co., ltd.) was adhered to the surface of the release film, and the adhesive tape was pressed by a pressing roller having a wire pressure of 5kgf/mm, and then the release film was cut into a short strip having a width of 25mm and a length of 150mm, and heated in an oven at 90℃for 20 hours. Then, one end of the adhesive tape was fixed, one end of the release film was gripped, and the release film side was pulled at a speed of 300mm/min to peel, and the T-shaped peel strength was measured. The T-shaped peel strength was measured using a tensile tester (AUTOGRAPHAG-X, manufactured by Shimadzu corporation). The results are shown in Table 1.

(high-speed peeling force after heating (PF 3))

An adhesive tape (trade name "31B" manufactured by Nito electric Co., ltd.) was adhered to the surface of the release film, and the adhesive tape was pressed by a pressing roller having a wire pressure of 5kgf/mm, and then the release film was cut into a short strip having a width of 25mm and a length of 150mm, and heated in an oven at 90℃for 20 hours. Thereafter, the release film side was fixed to the metal plate with a double-sided tape, one end of the adhesive tape was gripped, the adhesive tape side was pulled at a speed of 30m/min, and the release strength was measured at 180 °. The 180℃peel strength was measured using a tensile TESTER (TESTER SANGYO CO,. LTD. A "high speed peel TESTER TE-701"). The results are shown in Table 1.

(preparation of adhesive and mold Release layer coating liquid)

Lauryl methacrylate (CH) ₂ ＝C(CH ₃ )COOC ₁₂ H ₂₅ ) Hydroxyethyl methacrylate (CH) ₂ ＝C(CH ₃ )COOC ₂ H ₄ OH), methyl methacrylate (CH ₂ ＝C(CH ₃ )COOCH ₃ ) 50:30:20, toluene was added so that the solid content was 40% by weight, and Azobisisobutyronitrile (AIBN) was added to the mixture at 0.5 mol% under a nitrogen stream to obtain a long chain alkyl group-containing acrylic resin.

Example 1

An acrylic resin containing a long chain alkyl group, a melamine resin (NIPPON CARBIDE INDUSTRUES co., inc. Manufactured by NicalackMW-30) as a crosslinking agent, a higher alcohol (pentadecanol manufactured by tokyo chemical industry co., ltd.) as a low molecular weight releasing agent, and p-toluenesulfonic acid (DRIER #900, hitachi chemical polymer co., ltd.) as a curing catalyst were added in the amounts described in table 1, and a solvent (toluene/mek=50/50: mass ratio) was further added so that the solid content concentration became 6.0 mass%, to obtain a releasing layer coating liquid.

(formation of release layer)

The obtained release layer coating liquid was applied to a corona-treated surface of a polyethylene terephthalate film (manufactured by Toyo Kabushiki Kaisha, E5100, thickness: 38 μm, surface roughness (Sa): 0.0365nm (corona-treated surface), surface maximum section height (St): 3.72, haze: 3.7%) using a gravure coater, and then dried at 130℃for 30 seconds to form a release layer having a thickness of 0.2. Mu.m. The obtained release film was evaluated for normal peel force, peel force after heating, and high-speed peel force after heating.

Examples 2 to 5 and comparative examples 1 and 2

A release layer was formed in the same manner as in example 1, except that the composition was changed to table 1. The obtained release film was evaluated for normal peel force, peel force after heating, and high-speed peel force after heating.

TABLE 1

< evaluation result >

According to the present invention, it is possible to provide a release layer film which has light releasability both before and after heating and can maintain light releasability even in the case of high-speed release. On the other hand, in comparative example 1, the ratio a/b of the weight (a) of the long-chain alkyl group-containing acrylic resin to the weight (b) of the crosslinking agent was outside the range of the present invention, and therefore, the high-speed peeling force (PF 3) after heating could not be measured. Further, the peeling force increases after heating, and the release layer and the adhesive tape cannot be peeled off. In addition, comparative example 2 does not contain the crosslinking agent (B), and therefore the adhesive tape cannot be peeled from the release layer even at normal temperature.

The present embodiments and examples are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown by the claims rather than the above embodiments, and is intended to include meanings equivalent to the claims, and all modifications within the scope.

Industrial applicability

The release film of the present invention can be applied to applications such as electronic component manufacturing processes where it is difficult to use a silicone release film.

Claims

1. The release film according to claim 1, wherein the release film comprises a substrate film and a release layer comprising at least an acrylic resin (A) containing a long-chain alkyl group and a crosslinking agent (B) and substantially no silicone component,

(I)0.1≤a/b≤7.0。

2. a release film, wherein the release layer further comprises a release agent (C), and a ratio C/b of a weight (b) of a crosslinking agent to a weight (C) of the release agent contained in the release layer satisfies formula (II):

(II)0.1≤c/b≤10.0。

3. the release film according to claim 1 or 2, wherein a normal peel force (PF 1) at a peel speed of 0.3m/min is 8000mN/50mm or less.

4. The release film according to any one of claims 1 to 3, wherein a peeling force (PF 2) after heating (90 ℃ for 20 hours) at a peeling speed of 0.3m/min is 2 times or less the normal peeling force (PF 1).

5. The release film according to any one of claims 1 to 4, wherein a peeling force (PF 3) after heating (90 ℃ for 20 hours) at a peeling speed of 30m/min is 10 times or less the normal peeling force (PF 1).

6. A laminated film comprising an adhesive layer laminated on at least one surface of the release film according to any one of claims 1 to 5.