CN113631376A

CN113631376A - Release sheet

Info

Publication number: CN113631376A
Application number: CN202080023464.8A
Authority: CN
Inventors: 黑川敦史; 远藤优季
Original assignee: Lintec Corp
Current assignee: Lintec Corp
Priority date: 2019-03-26
Filing date: 2020-03-19
Publication date: 2021-11-09
Also published as: WO2020196222A1; JPWO2020196222A1; TW202100346A; KR20210146894A

Abstract

The release sheet comprises a release layer and a base, wherein the release layer comprises a cured product of a release agent composition comprising a phenoxy resin (A), an amino resin (B), and an organosilicon compound (C) having a crosslinkable functional group. The release sheet has a release layer which is excellent in organic solvent resistance, can impart an appropriate release force, and is excellent in curl resistance.

Description

Release sheet

Technical Field

The present invention relates to a release sheet

Background

In general, a release sheet includes a base material such as paper, plastic film, or polyethylene laminated paper, and a release layer provided on the base material. The release layer can be formed, for example, by coating a release agent composition containing a reactive compound on a substrate and curing it.

Release sheets are widely used as protective sheets for pressure-sensitive adhesive layers of pressure-sensitive adhesive sheets and the like, process films for producing resin sheets, process films for forming ceramic green sheets, process films for producing synthetic leathers, and the like.

Such a release sheet is often used in such a manner that a coating liquid containing an organic solvent is applied on a release layer thereof and a layer of the coating liquid is dried at high temperature. In such applications, the release layer of the release sheet needs to have both solvent resistance and heat resistance. In recent years, various components have been increasingly used in coating agents applied to release sheets, and in addition, organic solvents having high polarity and organic solvents having high boiling points have been increasingly used for the purpose of stability of the coating agents. Therefore, further resistance to organic solvents is required for the release layer.

When the degree of crosslinking of the release layer is increased to meet such a demand, the curl of the release sheet increases, and there may be a problem that the handling suitability of the release sheet and the shape stability of a product manufactured using the release sheet are impaired.

For example, patent document 1 describes a release sheet having a release layer formed from a release agent composition containing at least polyolefin, isocyanate having three or more isocyanate groups in one molecule, and polyolefin polyol.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-52207

Disclosure of Invention

Problems to be solved by the invention

However, a preferable value of the peeling force of the peeling sheet generally varies depending on the application and the type of the object to be laminated, and for example, a lower peeling force is desirable in order to facilitate the peeling operation at the time of peeling. On the other hand, when the holding property (anti-peeling property) of the object to be laminated is prioritized, a high peeling force is preferable, and therefore a peeling sheet having an appropriate peeling force without excessively low peeling force is required. That is, it is required to design a release agent composition capable of coping with a release force in conformity with a usage pattern of a product manufactured using the release sheet.

In addition, the release sheet has a risk of curling. Therefore, the release sheet is required to have not only appropriate releasability but also the ability to suppress the occurrence of curling of the release sheet (i.e., to exhibit good curl resistance).

Accordingly, an object of the present invention is to provide a release sheet having a release layer which is excellent in resistance to an organic solvent, can impart a suitable release force to the release layer, and is excellent in curl resistance.

Means for solving the problems

The present inventors have found that a release sheet having a release layer formed from a release agent composition containing a phenoxy resin (a), an amino resin (B), and an organosilicon compound (C) having a crosslinkable functional group can solve the above problems.

That is, the present invention relates to the following [1] to [7 ].

[1] A release sheet having a base material and a release layer, wherein,

the release layer contains a cured product of a release agent composition containing a phenoxy resin (A), an amino resin (B), and an organosilicon compound (C) having a crosslinkable functional group.

[2] The release sheet according to [1], wherein the content of the phenoxy resin (a) and the amino resin (B) in the release agent composition is (a): 15:85 to 90:10 by mass ratio.

[3] The release sheet according to the above [1] or [2], wherein the content of the organosilicon compound (C) having a crosslinkable functional group in the release agent composition is 0.1 to 10 parts by mass with respect to 100 parts by mass of the total of the phenoxy resin (A) and the amino resin (B).

[4] The release sheet according to any one of the above [1] to [3], wherein the phenoxy resin (A) has a glass transition temperature of 60 to 160 ℃.

[5] The release sheet according to any one of the above [1] to [4], wherein the crosslinkable functional group contained in the crosslinkable functional group-containing organosilicon compound (C) is a hydroxyl group.

[6] The release sheet according to any one of the above [1] to [5], wherein the crosslinkable functional group-containing organosilicon compound (C) comprises at least one member selected from the group consisting of a polyester-modified hydroxyl-containing polysiloxane, a polyether-modified hydroxyl-containing polysiloxane, and a polyether ester-modified hydroxyl-containing polysiloxane.

[7] The release sheet according to any one of the above [1] to [6], wherein a pressure-sensitive adhesive layer is attached to the release layer, and a release force when the release layer is released from the pressure-sensitive adhesive layer is 6000mN/20mm or less.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a release sheet having a release layer which is excellent in organic solvent resistance, can impart an appropriate release force, and is also excellent in curl resistance can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view of a release sheet according to an embodiment of the present invention.

Description of the symbols

1 Release sheet

10 base material

11 peeling layer

Detailed Description

In the present specification, "solid component" refers to a component other than the solvent among components contained in the release agent composition.

In the present specification, the property of holding an object obtained by laminating release sheets until the release sheet is peeled off from the object is also referred to as "anti-peeling property".

In the present specification, the lower limit and the upper limit recited in stages for a preferable numerical range (for example, a range of contents) may be independently combined. For example, according to the description of "preferably 10 or more, more preferably 30 or more, further preferably 40 or more, and preferably 90 or less, more preferably 80 or less, and further preferably 70 or less", as the preferable range, a range in which the lower limit value and the upper limit value are independently selected, such as "10 or more and 70 or less", "30 or more and 70 or less", and "40 or more and 80 or less", can be selected. In addition, according to the same description, a range in which one of the lower limit value and the upper limit value is limited, for example, "40 or more" or "70 or less" may be individually selected. The preferable ranges that can be selected according to the description of "preferably 10 or more and 90 or less, more preferably 30 or more and 80 or less, further preferably 40 or more and 70 or less", "preferably 10 to 90, more preferably 30 to 80, further preferably 40 to 70" are also the same. In the present specification, in the description of the numerical range, for example, the description of "10 to 90" is the same as the meaning of "10 or more and 90 or less".

[ constitution of Release sheet ]

The release sheet of the present invention has a substrate and a release layer provided on the substrate.

Fig. 1 is a schematic cross-sectional view showing a release sheet according to an embodiment of the present invention. The release sheet 1 has a substrate 10 and a release layer 11 provided on the substrate 10. The release layer 11 is a layer of a cured product of a release agent composition containing a phenoxy resin (a) and an amino resin (B) as binder components and containing an organosilicon compound (C) having a crosslinkable functional group as a release component.

In one embodiment of the present invention, the release sheet may have release layers (not shown) on both surfaces of the substrate 10. At this time, at least one of the plurality of release layers may be the release layer 11 as long as the effects of the present invention are not impaired, and in the case where a plurality of release layers 11 are present, the compositions of the release agent compositions forming the respective release layers 11 may be the same or different from each other.

In each of the above embodiments, the substrate 10 and the release layer 11 may be formed only, and another layer such as an easy-adhesion layer and an antistatic layer, which are not shown, may be provided between the substrate 10 and the release layer 11.

Hereinafter, the release layer and the substrate constituting the release sheet of the present invention will be described.

< Release layer >

The release sheet of the present invention has a release layer which is a layer of a cured product that can be formed from a release agent composition containing a phenoxy resin (a) and an amino resin (B) as binder components and containing an organosilicon compound (C) having a crosslinkable functional group as a release component.

Hereinafter, a release agent composition as a material for forming a release layer will be described.

In the following description, the "content of each component in the release agent composition" may be regarded as "content of each component in the release layer formed from the release agent composition". The content may be a value calculated from the amount of each component added.

In the present specification, the contents of the respective components, the total contents, and the ratios of the respective components are all values converted into solid contents.

(stripper composition)

The release agent composition contains a phenoxy resin (A) and an amino resin (B) as binder components, and contains an organosilicon compound (C) having a crosslinkable functional group as a release component.

In the following description, the "organosilicon compound (C) having a crosslinkable functional group" may be abbreviated as "organosilicon compound (C)".

The present inventors have made various studies on the formulation of a release layer using a release agent composition other than a silicone-based release agent composition in order to find a formulation capable of solving the above problems. As a result, it was found that a release layer formulation using a release agent composition satisfying the above conditions is an effective formulation, and the present invention was completed.

In one embodiment of the present invention, the release agent composition may further contain components other than the above-described phenoxy resin (a), amino resin (B), and organosilicon compound (C) having a crosslinkable functional group, within a range in which the effects of the present invention are not impaired.

Hereinafter, each component contained in the release agent composition will be described.

(phenoxy resin (A))

The stripping agent composition comprises phenoxy resin (A). When the releasing agent composition contains the amino resin (B) and the organosilicon compound (C) having a crosslinkable functional group, which will be described later, and further contains the phenoxy resin (a), the releasing force can be controlled to be applicable to a wide range of applications. Further, since the phenoxy resin has an aromatic ring in its skeleton, a rigid cured product can be formed without increasing the degree of crosslinking. Therefore, a release agent composition having both solvent resistance and low curling properties can be designed.

In the present specification, the "phenoxy resin" includes, for example, a thermoplastic resin which is a reaction product of a phenol compound such as a bisphenol compound and an epihalohydrin such as epichlorohydrin or an epoxy compound.

Examples of the phenoxy resin (a) include phenoxy resins having at least one structure selected from a bisphenol a-derived structure, a bisphenol F-derived structure, a bisphenol S-derived structure, a bisphenol acetophenone-derived structure, a biphenyl diol structure, a biphenyl structure, a triphenylmethane structure, a novolak (Novolac) structure, a fluorene structure, a dicyclopentadiene structure, a norbornene structure, a naphthalene structure, an anthracene structure, an adamantane structure, a terpene structure, a cyclohexane structure, and a trimethylcyclohexane structure.

The terminal functional group of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group.

From the viewpoint of improving the heat resistance of the obtained release sheet, the glass transition temperature (Tg) of the phenoxy resin (a) is preferably 60 ℃ or higher, more preferably 65 ℃ or higher, still more preferably 70 ℃ or higher, still more preferably 80 ℃ or higher, particularly preferably 110 ℃ or higher, and most preferably 140 ℃ or higher. The upper limit of the glass transition temperature (Tg) is not particularly limited as long as the effect of the present invention is not impaired, and is preferably 160 ℃. The glass transition temperature (Tg) can be measured, for example, by the method described in the examples below. The glass transition temperature (Tg) of the phenoxy resin (a) can be adjusted by, for example, selecting the main skeleton of the phenoxy resin, the kind of elements contained in the phenoxy resin, the kind and structure of groups bonded to the main skeleton of the phenoxy resin, and the like.

The number average molecular weight (Mn) of the phenoxy resin (A) is preferably 5000 to 30000, more preferably 7000 to 25000, and still more preferably 9000 to 20000. The number average molecular weight (Mn) is a value in terms of polystyrene measured by Gel Permeation Chromatography (GPC).

The phenoxy resin (a) may be used alone or in combination of two or more.

(amino resin (B))

The release agent composition contains an amino resin (B). In the present specification, the term "amino resin" refers to a general term for compounds obtained by the reaction of a compound having an amino group such as melamine, urea, aniline, guanamine, and the like with an aldehyde such as formaldehyde, acetaldehyde, and the like.

Examples of the amino resin include: melamine resins, urea resins, aniline resins, guanamine resins, and the like. Among them, a melamine resin is preferable from the viewpoint of improving the curability of the release agent composition and the solvent resistance of the release layer.

The melamine resin is preferably at least one selected from the group consisting of a methylolated melamine resin, an iminomethylolated melamine resin, a methylated melamine resin, an ethylated melamine resin, a propylated melamine resin, a butylated melamine resin, a hexylated melamine resin, and an octylated melamine resin, and more preferably at least one selected from the group consisting of a methylolated melamine resin, an iminomethylolated melamine resin, and a methylated melamine resin. Among these, methylated melamine resins are more preferable from the viewpoint of low-temperature curability of the releasable composition. The amino resin (B) may be used alone or in combination of two or more.

(content and content ratio of phenoxy resin (A) and amino resin (B))

From the viewpoint of preventing the binder component in the release agent composition from being excessively small, the total content of the phenoxy resin (a) and the amino compound (B) in the release agent composition is preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and still further preferably 95% by mass or more, based on the total amount (100% by mass) of the release agent composition.

The content ratio (A/B) of the phenoxy resin (A) to the amino resin (B) is preferably 15/85-90/10 in terms of mass ratio. When a/B is 90/10 or less, the amino resin (B) is sufficiently present, and therefore, good solvent resistance can be easily ensured. When the a/B is 15/85 or more, it is easier to prevent the occurrence of curling presumably due to an excessive condensation reaction. From the viewpoint of more easily preventing the occurrence of curling, A/B is more preferably 17/83 to 85/15, still more preferably 20/80 to 83/17, and still more preferably 20/80 to 80/20.

(organosilicon Compound (C) having crosslinkable functional group)

In the present invention, an organosilicon compound (C) having a crosslinkable functional group is used.

In the present specification, the "crosslinkable functional group" refers to a functional group that reacts with the phenoxy resin (a) and the melamine compound (B).

The crosslinkable functional group of the organosilicon compound (C) can be selected depending on the relationship with the phenoxy resin (a) and the melamine compound (B).

Examples of the crosslinkable functional group of the organosilicon compound (C) include a hydroxyl group, a carboxyl group, an epoxy group, an amino group, an isocyanate group, a thiol group, and a vinyl group.

Among them, the crosslinkable functional group is preferably a hydroxyl group from the viewpoint of better reactivity with the phenoxy resin (a) and the melamine compound (B).

The organosilicon compound (C) may have at least one crosslinkable functional group, and preferably has two or more crosslinkable functional groups. When the organosilicon compound (C) has two or more crosslinkable functional groups, these functional groups may be the same as or different from each other, and are preferably the same as each other.

As the organosilicon compound (C) having a crosslinkable functional group, a modified polysiloxane in which both terminals, one terminal, or a side chain such as an alkyl group of the polysiloxane are substituted with another functional group can be used. Preferred examples thereof include polyether-modified hydroxyl-containing polysiloxanes, polyether ester-modified hydroxyl-containing polysiloxanes, polyester-modified hydroxyl-containing polysiloxanes, methanol-modified polysiloxanes, amino-modified polysiloxanes, epoxy-modified polysiloxanes, carboxyl-modified polysiloxanes, mercapto-modified polysiloxanes, and the like, in which both terminals, one terminal or a side chain such as an alkyl group of the polysiloxane are substituted with another functional group.

More preferred examples include modified polydimethylsiloxanes such as polyether-modified hydroxyl-containing polydimethylsiloxane, polyether ester-modified hydroxyl-containing polydimethylsiloxane, polyester-modified hydroxyl-containing polydimethylsiloxane, carbinol-modified polydimethylsiloxane, amino-modified polydimethylsiloxane, epoxy-modified polydimethylsiloxane, carboxyl-modified polydimethylsiloxane, and mercapto-modified polydimethylsiloxane, in which methyl groups at both ends, one end, or a side chain of polydimethylsiloxane are substituted with other functional groups.

From the viewpoint of better reactivity with the phenoxy resin (a) and the melamine compound (B), preferred are polyether-modified hydroxyl-containing polydimethylsiloxane, polyether ester-modified hydroxyl-containing polydimethylsiloxane, polyester-modified hydroxyl-containing polydimethylsiloxane, and methanol-modified polydimethylsiloxane. The organosilicon compound (C) having a crosslinkable functional group may be used alone or in combination of two or more.

As the organosilicon compound (C) having a crosslinkable functional group, commercially available products such as "BYK-370", "BYK-375", "BYK-377" (manufactured by YK-Chemie Japan Co., Ltd.), and "X-22-4015", "X-22-3701E", "X-22-3710", "X-22-162C", "X-22-4039", "KF-6000", "KF-6001", "KF-6002" and "KF-6003" (manufactured by shin-Etsu chemical Co., Ltd.) can be used.

When the silicone compound (C) having a crosslinkable functional group is contained in addition to the phenoxy resin (a) and the melamine compound (B), and the release agent composition is heated and reacted with each other, the phenoxy resin (a) and the melamine compound (B) as the binder resin components react with the crosslinkable functional group of the silicone compound (C), whereby the silicone compound (C) is fixed in the obtained release layer. Therefore, it is considered that the silicone skeleton portion of the organosilicon compound (C) fixed in the release layer functions as a release component, whereby it is possible to impart an appropriate release force to the release layer and to suppress the transfer of the organosilicon compound (C) from the release layer to another member in contact with the release layer.

The content of the organosilicon compound (C) in the stripper composition is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, even more preferably 0.7 to 7.5 parts by mass, and even more preferably 1.0 to 5.0 parts by mass, based on 100 parts by mass of the total of the phenoxy resin (A) and the amino resin (B). When the content of the organosilicon compound (C) is 0.1 parts by mass or more, a suitable peeling force can be easily applied to the release layer, and when the content is 10 parts by mass or less, transfer of the organosilicon compound (C) from the release layer can be reliably prevented and excessive consumption of the organosilicon compound (C) can be avoided.

(acid catalyst)

The stripping agent composition may further comprise an acid catalyst. By using an acid catalyst, the crosslinking reactivity of the phenoxy resin (a) and the amino resin (B) with the organosilicon compound (C) can be improved, and the stability of the peeling force of the peeling layer with time can be easily further improved.

The acid catalyst is not particularly limited, and for example, organic acid catalysts such as p-toluenesulfonic acid, methanesulfonic acid, and alkyl phosphate are suitable.

The acid catalysts may be used alone or in combination of two or more.

The amount of the acid catalyst used is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and still more preferably 1 to 5 parts by mass, based on 100 parts by mass of the total amount of the phenoxy resin (a) and the amino resin (B).

(other additives)

The additive composition may contain, as necessary, various additives other than the above-mentioned phenoxy resin (a), amino resin (B), organosilicon compound (C) having a crosslinkable functional group, and acid catalyst, within a range not to impair the effects of the present invention.

Examples of such additives include various additives such as antioxidants, ultraviolet absorbers, inorganic or organic fillers, antistatic agents, surfactants, photoinitiators, and light stabilizers.

(organosilicon Compound having no crosslinkable functional group)

The release agent composition preferably contains substantially no organosilicon compound having no crosslinkable functional group.

This is because, when a release sheet having a release layer formed of a release agent composition containing an organosilicon compound having no crosslinkable functional group is used for an electronic material, the organosilicon compound may be transferred to an electronic component, which may cause corrosion and malfunction of the electronic component.

The content of the organosilicon compound having no crosslinkable functional group in the release agent composition is preferably less than 5.0% by mass, more preferably less than 2.0% by mass, still more preferably less than 1.0% by mass, yet still more preferably less than 0.1% by mass, and particularly preferably less than 0.01% by mass, based on the total amount (100% by mass) of the release agent composition.

(isocyanate Compound)

The releasing agent composition preferably contains substantially no isocyanate compound from the viewpoint of solvent resistance.

The content of the isocyanate compound in the release agent composition is preferably less than 1.0% by mass, more preferably less than 0.1% by mass, even more preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass, based on the total amount of the release agent composition (100% by mass of the solid content).

(Diluent solvent)

The release agent composition may be in the form of a solution prepared by adding a diluting solvent to the above components, from the viewpoint of improving the coatability to a substrate.

The diluting solvent can be selected from organic solvents having good solubility of the phenoxy resin (a), the amino resin (B), and the organosilicon compound (C) having a crosslinkable functional group (hereinafter sometimes referred to as "components (a), (B), and (C)").

Examples of such organic solvents include toluene, xylene, heptane, octane, methanol, ethanol, isopropanol, isobutanol, n-butanol, ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, and tetrahydrofuran.

These may be used alone or in combination of two or more.

The organic solvent used as the diluting solvent may be the organic solvent used in the synthesis of the above-mentioned components (a), (B), and (C) as it is, or may be one or more organic solvents other than the organic solvent used in the synthesis of the above-mentioned components (a), (B), and (C) so that the release agent composition can be uniformly applied.

The amount of the diluting solvent may be appropriately selected so as to achieve an amount having a moderate viscosity when the release agent composition is applied. Specifically, the amount of the diluting solvent may be adjusted so that the concentration of the solid content in the solution of the release agent composition is preferably in the range of 0.1 to 15% by mass, more preferably in the range of 0.2 to 10% by mass, and still more preferably in the range of 0.5 to 5% by mass.

< thickness of Release layer >

The thickness of the release layer is not particularly limited, and may be usually 25 to 1000nm, preferably 50 to 500 nm. When the thickness of the release layer is 25nm or more, variation in the release force due to variation in the amount of coating can be suppressed. When the thickness of the release layer is 1000nm or less, the curability of the coating film of the release agent composition can be improved.

The thickness of the release layer can be measured, for example, by the method described in the examples described later.

< substrate >

Examples of the base material used for the release sheet of the present invention include paper materials such as fully-pulped paper, clay-coated paper, cast-coated paper, and kraft paper, laminated paper obtained by laminating a thermoplastic resin such as a polyethylene resin on these paper materials, paper material sheets such as synthetic paper, and polyolefin resins such as polyethylene resins and polypropylene resins; polyester resins such as polybutylene terephthalate resins, polyethylene terephthalate resins, and polyethylene naphthalate resins; a polyetherimide resin; an acetate resin; a polystyrene resin; sheets of synthetic resins such as vinyl chloride resins, and the like.

The substrate may be a single layer, or may be a multilayer of 2 or more layers of the same kind or different kinds.

The thickness of the substrate is not particularly limited, and may be usually 10 to 300. mu.m, preferably 20 to 200. mu.m. When the thickness of the substrate is 10 to 300 μm, for example, rigidity and strength suitable for processing such as printing, cutting, and sticking can be imparted to an adhesive sheet or the like using a release sheet.

In the case where a synthetic resin is used as the substrate, the surface of the substrate on which the release layer is provided may be subjected to surface treatment by a method such as oxidation or roughening, as required, in order to improve adhesion between the substrate and the release layer.

Examples of the oxidation method include corona discharge surface treatment, chromic acid surface treatment (wet method), flame surface treatment, hot air surface treatment, ozone/ultraviolet irradiation surface treatment, and the like. Examples of the method of forming the concavity and convexity include a sand blast method and a solvent treatment method. These surface treatment methods may be appropriately selected depending on the type of the base material, and in general, a corona discharge surface treatment method is preferably used from the viewpoint of effects and workability. In addition, a primer treatment may be performed.

The surface of the release sheet of the present invention on the release layer side may be subjected to embossing or the like to form irregularities on the surface of the release sheet.

In addition, the release sheet of the present invention may further include another layer such as an easy-adhesion layer or an antistatic layer between the base material and the release layer. By providing the release sheet with an easily adhesive layer, the release layer can be effectively prevented from falling off the release sheet.

The easy adhesion layer is usually formed by applying an easy adhesion coating agent to the release layer side surface of the substrate. Examples of the easy-adhesion coating agent includePolyester resin, urethane resin, acrylic resin, melamine resin, polyester resin, urethane resin, resin containing

An oxazoline-based resin, a carbodiimide group-containing resin, an epoxy group-containing resin, an isocyanate-containing resin, and a copolymer thereof, and a coating agent containing a natural rubber and a synthetic rubber as a main component.

These resins may be used singly or in combination of two different resins. In order to improve the coating property of the easy-adhesion coating agent on the surface of the base material and the adhesion between the base material and the easy-adhesion layer, the surface of the base material to be coated with the easy-adhesion coating agent may be subjected to a surface treatment such as a chemical treatment or an electric discharge treatment.

The thickness of the easy adhesion layer is preferably 50nm or more, and more preferably 100nm or more. The thickness is preferably 5 μm or less, and more preferably 1 μm or less. By setting the thickness to 50nm or more, the effect of the easy adhesion layer can be obtained well. When the thickness is 5 μm or less, the surface of the easy-adhesion layer opposite to the substrate has good sliding properties, and the easy-adhesion layer is coated with the release agent composition in good workability.

[ Properties of Release sheet ]

< peeling force >

In general, a preferable value of the peeling force of the peeling sheet differs depending on the application to be used and the type of the object to be laminated, and a lower peeling force is preferable in some cases for smooth peeling operation at the time of peeling, and a high peeling force is preferable in some cases for improved retention of the object until the peeling operation.

The release agent composition used in the release sheet of the present invention can cope with both low release force and high release force, and can impart an appropriate release force to the release sheet. For example, by changing the content ratio of the phenoxy resin (a) and the amino resin (B) in the release layer of the release agent composition to be a cured product, and changing the content and type of the organosilicon compound (C) having a crosslinkable functional group, it is possible to improve solvent resistance, prevent curling, and set the release force to various values.

The release force of the release layer exhibited by the release sheet is preferably 6000mN/20mm or less, more preferably 5500mN/20mm or less, further preferably 5000mN/20mm or less, and further preferably 50mN/20mm or more, more preferably 90mN/20mm or more, further preferably 100mN/20mm or more, further preferably 300mN/20mm or more, and particularly preferably 500mN/20mm or more.

Since the peeling force of the peeling sheet varies depending on the object to be laminated, the evaluation method thereof can be measured by the method described in the examples described later.

[ use of Release sheet ]

The release sheet of the present invention can be used as a protective sheet for various pressure-sensitive adhesive bodies such as pressure-sensitive adhesive sheets, and for example, can be used by being stuck to a pressure-sensitive adhesive layer-side surface of a pressure-sensitive adhesive sheet including a substrate and a pressure-sensitive adhesive layer provided on one surface of the substrate. Further, the resin composition can be used as a process film for producing various resin sheets, ceramic green sheets, synthetic leathers, various composite materials, and the like. In the case of use as a process film, the process film is used in a step of peeling various sheet materials from a release sheet, the sheet materials being formed by casting a resin, a ceramic slurry, or the like and applying the surface of the release sheet on the release layer side. The release sheet of the present invention is particularly preferably used for electronic device applications because the release layer is formed from a non-silicone release agent composition. For example, the release sheet can be suitably used as a release sheet for an adhesive sheet for temporarily fixing and marking the contents of components when electronic components are assembled in the production process of electronic components such as relays, various switches, connectors, motors, and hard disks.

[ method for producing Release sheet ]

The release sheet of the present invention can be produced, for example, as follows: a release agent composition is applied to at least one surface of a substrate, and heat treatment is performed to react a phenoxy resin (A), an amino resin (B), and an organosilicon compound (C) having a crosslinkable functional group, thereby forming a cured product as a release layer.

As described above, the release agent composition may be in the form of a solution diluted with a diluting solvent.

The heat treatment temperature is preferably 100 to 170 ℃, and more preferably 130 to 160 ℃. The heat treatment time is not particularly limited, but is preferably 30 seconds to 5 minutes.

Examples of the coating method of the release agent composition include a gravure coating method, a bar coating method, a spray coating method, a spin coating method, an air knife coating method, a roll coating method, a blade coating method, a gate roll coating method, and a die coating method.

The coating thickness of the release agent composition is preferably adjusted so that the thickness of the obtained release layer is within the above range.

Examples

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

The physical property values in the following examples and comparative examples are values measured by the following methods.

[ thickness of the peeling layer ]

The thickness of the release layer was measured using an ellipsometer (product name: ellipsometer 2000U, manufactured by j.a. woollam Japan).

[ glass transition temperature (Tg) ]

The glass transition temperature (Tg) of the phenoxy resin was measured by heating from 30 ℃ to 200 ℃ at a heating rate of 10 ℃ per minute using a differential scanning calorimeter (product name "DSC Q2000" manufactured by TA Instruments Japan).

[ examples and comparative examples ]

The release sheets of examples 1 to 11 and comparative examples 1 to 3 were produced by the following procedure. In the following description, unless otherwise specified, "parts by mass" is a value calculated as a solid content.

< example 1>

As the phenoxy resin (a), a product name manufactured by mitsubishi chemical corporation: YX7200B35 (Tg: 150 ℃, epoxy equivalent: 3000-16000).

As the amino resin (B), a methylated melamine resin (product name "CYMEL 303 LF" manufactured by Allnex Japan) was used.

As the organosilicon compound (C) having a crosslinkable functional group, polyether-modified hydroxyl-containing polydimethylsiloxane (product name BYK-377, manufactured by YK-Chemie Japan) was used.

As the acid catalyst, p-toluenesulfonic acid was used. The p-toluenesulfonic acid was used in a state diluted with a mixed solvent of methanol and isopropyl alcohol (mass ratio methanol/isopropyl alcohol 41.2/9.4) to a solution having a solid content concentration of 50 mass%.

A release agent composition was obtained by mixing 80 parts by mass of the phenoxy resin, 20 parts by mass of the methylated melamine compound, 1 part by mass of the modified silicone resin, and 3.0 parts by mass of p-toluenesulfonic acid (solid content ratio).

The obtained release agent composition was diluted to a solid content concentration of 4.3 mass% using a mixed solution (mass ratio 4:5:1) of toluene, methyl ethyl ketone and cyclohexanone to prepare a coating solution of the release agent composition.

The coating liquid of the obtained release agent composition was applied to one surface of a polyethylene terephthalate film (product name: DIAFOIL T-100, product name, manufactured by Mitsubishi chemical corporation) having a thickness of 50 μm using a Meyer bar to form a coating film.

Subsequently, the coating film was dried at 150 ℃ for 1 minute and cured to form a release layer having a thickness of 200nm, thereby obtaining a release sheet.

< example 2>

A release sheet was obtained in the same manner as in example 1, except that the amount of the organosilicon compound (C) used was changed to 5 parts by mass.

< example 3>

A release sheet was obtained in the same manner as in example 1, except that polyether ester-modified hydroxyl group-containing polydimethylsiloxane (BYK-375, product name, manufactured by YK-Chemie Japan) was used as the organosilicon compound (C).

< example 4>

A release sheet was obtained in the same manner as in example 1, except that polyester-modified hydroxyl group-containing polydimethylsiloxane (BYK-370, product name, manufactured by YK-Chemie Japan) was used as the organosilicon compound (C).

< example 5>

A release sheet was obtained in the same manner as in example 1, except that a side chain type methanol-modified silicone oil (product name X-22-4039, manufactured by shin-Etsu chemical Co., Ltd.) was used as the organosilicon compound (C).

< example 6>

A release sheet was obtained in the same manner as in example 1, except that both-end type methanol-modified silicone oil (product name KF-6003, manufactured by shin-Etsu chemical Co., Ltd.) was used as the organosilicon compound (C).

< example 7>

A release sheet was obtained in the same manner as in example 1, except that the amount of the phenoxy resin (a) was changed to 50 parts by mass and the amount of the melamine resin (B) was changed to 50 parts by mass.

< example 8>

A release sheet was obtained in the same manner as in example 1, except that the amount of the phenoxy resin (a) was changed to 20 parts by mass and the amount of the melamine resin (B) was changed to 80 parts by mass.

< example 9>

A release sheet was obtained in the same manner as in example 1, except that the phenoxy resin (A) was changed to the product name EXA-123 (Tg: 90 ℃ C.) manufactured by DIC.

< example 10>

A release sheet was obtained in the same manner as in example 1, except that 4275 (Tg: 68 ℃) which is a product name manufactured by Mitsubishi chemical corporation was used as the phenoxy resin (A).

< example 11>

A release sheet was obtained in the same manner as in example 1, except that 1255HX30 (Tg: 85 ℃ C.) manufactured by Mitsubishi chemical corporation was used as the phenoxy resin (A).

< comparative example 1>

A release sheet was obtained in the same manner as in example 1, except that the organosilicon compound (C) was not used.

< comparative example 2>

A release sheet was obtained in the same manner as in example 1, except that the amount of the melamine resin (B) used was changed to 100 parts by mass and the phenoxy resin (a) was not used.

< comparative example 3>

A release sheet was obtained in the same manner as in example 1, except that 5 parts by mass of a phenyl-modified silicone resin (product name KF-54, manufactured by shin-Etsu chemical Co., Ltd.) was used instead of 1 part by mass of the silicone compound (C) having a crosslinkable functional group. The phenyl-modified silicone resin is a non-crosslinkable silicone compound having substantially no crosslinkable functional group.

The following measurements and evaluations were carried out on the release sheets of examples 1 to 11 and comparative examples 1 to 3.

[ measurement of peeling force ]

A polyester adhesive tape (manufactured by Ridong electric Co., Ltd., model No.31B) having a width of 20mm was adhered to the release layer of the release sheets of examples 1 to 11 and comparative examples 1 to 3 using a 2kg roll to prepare samples for measuring the release force.

After the completion of the sticking for 30 minutes, the obtained sample was fixed to a universal tensile tester (trade name: Autograph AGS-20NX, manufactured by Shimadzu corporation) and the adhesive tape was peeled from the release layer at a tensile speed of 0.3 m/min in a 180 ℃ direction in accordance with JIS K6854:1999, whereby the peel force (mN/20mm) of the release sheet was measured. The results are shown in Table 1.

[ transfer resistance to Silicone ]

The pressure-sensitive adhesive surface of an acrylic pressure-sensitive adhesive Tape (product name: "31B Tape", manufactured by Ridong electric Co., Ltd.) was adhered to the release layer of the release sheets of examples 1 to 11 and comparative examples 1 to 3, and then allowed to stand at room temperature of 23 ℃ under a gas atmosphere having a humidity of 50% for 24 hours. Then, the amount of transfer of the silicone from the release layer to the adhesive tape was measured by calculating the silicon atom ratio (atomic%) based on the amounts of silicon atoms (Si), carbon atoms (C), and oxygen atoms (O) (XPS count) measured by X-ray photoelectron spectroscopy (XPS) with respect to the adhesive surface of the adhesive tape exposed by peeling the release film, by the following formula. The results are shown in Table 1.

Silicon atom ratio (atomic%) [ (Si element amount)/{ (C element amount) + (O element amount) + (Si element amount) } x 100

Then, the silicone transfer resistance of the release layer was determined based on the following criteria.

The silicon atom ratio of A is less than 1.00 atom%

Silicon atom ratio of C is 1.00 atom% or more

[ curl resistance ]

The coating liquids described in examples 1 to 11 and comparative examples 1 to 3 were applied to one surface of the polyethylene terephthalate film so that the film thickness after drying was 1 μm. The test piece was cut into a 10cm square and stored at 120 ℃ for 24 hours. Next, the test piece was placed on a horizontal table, the four corners of the test piece were measured for warpage, and the curl resistance was evaluated according to the following criteria. The results are shown in Table 1.

S: the average value of the warping is less than 1 mm.

A: the average value of the warpage is 1mm or more and less than 3 mm.

B: the average value of the tilting is more than 3mm and less than 5 mm.

C: the average value of the tilting is more than 5 mm.

[ evaluation of solvent resistance ]

A nonwoven fabric impregnated with methyl ethyl ketone (product name: BEMCOT, manufactured by Asahi chemical Co., Ltd.) was placed on the release layer of the release sheets of examples 1 to 11 and comparative examples 1 to 3, and the sheet was wiped 5 times with a load of 100g from above. The surface of the release layer was visually observed, and evaluated as "a" if the surface of the release layer was unchanged, and evaluated as "C" if whitening occurred on the surface of the release layer due to scratching or the like. The results are shown in

Table 1.

The following results are shown in Table 1.

The release sheets of examples 1 to 11 were those capable of setting the release force to various values and capable of coping with various applications, and each had a release layer formed from a release agent composition containing a phenoxy resin (a) having a specific glass transition temperature, an amino resin (B), and an organosilicon compound (C) having a crosslinkable functional group. In addition, the release sheets of examples 1 to 11 were also excellent in solvent resistance. Further, the release sheets of examples 1 to 11 were slightly changed depending on the content ratio of the phenoxy resin (a) and the amino resin (B), but the occurrence of curling was suppressed. In addition, the release sheets of examples 1 to 11 had moderate release force and satisfactorily suppressed the transfer of silicone.

In contrast, the release sheet of comparative example 1 having a release layer formed from a release agent composition containing no organosilicon compound (C) having a crosslinkable functional group had too large a release force and was rarely applicable for use. In addition, the release sheet of comparative example 2 having a release layer formed of a release agent composition containing no phenoxy resin (a) generated a large curl. Further, with the release sheet of comparative example 3 having a release layer formed from a release agent composition containing the organosilicon compound (C) having no crosslinkable functional group, a large amount of the organosilicon compound was transferred to the adhesive tape.

Industrial applicability

The release sheet of the present invention is useful as a protective sheet for various adherends such as an adhesive sheet, and also as a process film for producing various resin sheets, ceramic green sheets, synthetic leathers, and various composite materials. Further, since the release layer of the release sheet of the present invention comprises a cured product of a release agent composition containing a silicone having a crosslinkable functional group, the release sheet can be suitably set in terms of release force, is excellent in solvent resistance, can suppress the occurrence of curling, and can suppress the transfer of an organic silicon compound from the release layer to a member in contact with the release layer, and therefore, the release sheet can be suitably used as a release sheet for various electronic devices, or as a release sheet for an adhesive sheet for temporary fixation, marking of the content of a component, or the like when an electronic component is assembled in a process for producing an electronic component.

Claims

1. A release sheet having a base material and a release layer, wherein,

2. The release sheet according to claim 1, wherein the content of the phenoxy resin (A) and the amino resin (B) in the release agent composition is (A): 15:85 to 90:10 by mass ratio.

3. The release sheet according to claim 1 or 2, wherein the content of the crosslinkable functional group-containing organosilicon compound (C) in the release agent composition is 0.1 to 10 parts by mass with respect to 100 parts by mass of the total of the phenoxy resin (a) and the amino resin (B).

4. The release sheet according to any one of claims 1 to 3, wherein the glass transition temperature of the phenoxy resin (A) is 60 to 160 ℃.

5. The release sheet according to any one of claims 1 to 4, wherein the crosslinkable functional group contained in the crosslinkable functional group-containing organosilicon compound (C) is a hydroxyl group.

6. The release sheet according to any one of claims 1 to 5, wherein the crosslinkable functional group-containing organosilicon compound (C) comprises at least one member selected from the group consisting of a polyester-modified hydroxyl-containing polysiloxane, a polyether-modified hydroxyl-containing polysiloxane, and a polyether ester-modified hydroxyl-containing polysiloxane.

7. The release sheet according to any one of claims 1 to 6, wherein an adhesive layer is bonded to the release layer, and a release force when the release layer is released from the adhesive layer is 6000mN/20mm or less.