KR20210060012A - Repeelable adhesive sheet - Google Patents

Abstract

Provided is a repeelable adhesive sheet including a base layer, a first adhesive layer formed on the upper surface of the base layer, and a second adhesive layer formed on the lower surface of the base layer, wherein some surfaces of the second adhesive layer are non-adhesive layer surfaces. The present invention can suppress the occurrence of pixel defects and warpage.

Description

Re-peelable adhesive sheet {REPEELABLE ADHESIVE SHEET}

The present invention relates to a releasable adhesive sheet. More specifically, the present invention includes a first adhesive layer and a second adhesive layer having different peel strengths after UV curing, so that selective peeling after UV curing is possible. It relates to a re-peelable pressure-sensitive adhesive sheet that can improve peelability.

A light-emitting device display device including an organic light-emitting device (OLED) is manufactured through several sequential processes. Among them, a temporary fixing process between the OLED panel and the carrier glass is required when the OLED encapsulant lamination process is in progress. For the temporary fixing process, a double-sided adhesive tape can be used.

The double-sided adhesive tape has an adhesive layer formed on the upper and lower surfaces of the base layer, so that the panel and the carrier glass can be simultaneously fixed. Meanwhile, after the fixing process is completed, the double-sided adhesive tape must be separated from the carrier glass.

In this regard, as a double-sided adhesive tape, a foaming type adhesive tape that can be easily peeled off from a carrier glass is used while a foaming process by heating occurs and the adhesive strength falls after heating. This is the principle that the foam contained in the adhesive layer is foamed when heated, thereby lowering the adhesive force and providing a gap between the carrier glass and the adhesive layer, thereby being separated from the carrier glass.

However, in the foamed adhesive tape, an essential heat treatment process is generally performed at a temperature of 100° C. or higher for 3 hours or more. In this process, the pixels are deteriorated and damaged, so that there may be a screen defect of the pixel display device. In addition, the encapsulation generally includes a metal layer as an inorganic encapsulation layer, and warpage may occur in the inorganic encapsulation layer by the above-described heat treatment process, so that a display device may be defective. Therefore, a re-peelable adhesive tape capable of solving the problems caused by the conventional foamed adhesive tape by heating must be developed.

The background technology of the present invention is disclosed in Korean Patent Publication No. 2009-0080073 and the like.

An object of the present invention is to provide a re-peelable adhesive sheet that provides high re-peelability upon peeling by an air blowing process.

Another object of the present invention is to provide a re-peelable pressure-sensitive adhesive sheet that enables selective peeling by providing two types of pressure-sensitive adhesive layers having different peel strengths after UV curing.

Another object of the present invention is that it can be applied to a lamination process with a panel by UV curing instead of a heat treatment process by thermal foaming, so that a re-peelable adhesive that can suppress the occurrence of pixel defects and warpage caused by the heat treatment process. It is to provide a sheet.

The releasable adhesive sheet of the present invention includes a base layer, a first adhesive layer formed on an upper surface of the base layer, and a second adhesive layer formed on a lower surface of the base layer, and among the lower surfaces of the second adhesive layer A non-adhesive layer surface is formed on some surfaces.

In one embodiment, the non-adhesive layer surface may be formed by a masking film.

In one embodiment, the masking film may be formed in a state that is recessed in the lower surface of the second adhesive layer.

In one embodiment, the area ratio of the total area of the masking film to the area of the lower surface of the second adhesive layer S3/S2 (S2 is the area of the lower surface of the second adhesive layer, S3 is the total area of the masking film ) May be 0.01 to 0.5.

In one embodiment, the area ratio S3/S2 may be 0.14 to 0.31.

In one embodiment, the masking film may be formed at a corner of an outer surface of the lower surface of the second adhesive layer.

In one embodiment, the masking film may have an angled corner.

In one embodiment, the masking film may have a UV transmittance of 50% or more.

In one embodiment, the base layer may include a colored film.

In one embodiment, the base layer may have a haze of 20% or less.

In one embodiment, the first adhesive layer and the second adhesive layer may have different storage modulus at 25°C.

In one embodiment, the first adhesive layer and the second adhesive layer may have different adhesive strength.

In one embodiment, the first adhesive layer and the second adhesive layer may each include a UV-curable (meth)acrylic adhesive layer.

In one embodiment, a third adhesive layer may be further formed between the second adhesive layer and the masking film.

In one embodiment, the third adhesive layer may include a NON UV curable (meth) acrylic adhesive layer.

The present invention provides a re-peelable pressure-sensitive adhesive sheet that provides high re-peelability upon peeling by an air blowing process.

The present invention provides a re-peelable pressure-sensitive adhesive sheet that enables selective peeling by providing two types of pressure-sensitive adhesive layers having different peel strengths after UV curing.

The present invention provides a re-peelable adhesive sheet that can be applied to a lamination process with a panel by UV curing instead of a heat treatment process by thermal foaming, thereby suppressing the occurrence of pixel defects and warpage caused by the heat treatment process. .

1 is a cross-sectional view of a releasable adhesive sheet according to an embodiment of the present invention.
FIG. 2 is a plan view of a lower surface of a second adhesive layer in the releasable adhesive sheet of FIG. 1.
3 is a plan view of a lower surface of a second adhesive layer in an adhesive sheet according to another embodiment of the present invention.
4 is a cross-sectional view of a releasable adhesive sheet according to another embodiment of the present invention.

It will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the present invention by examples. The present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and the same reference numerals are assigned to the same or similar components throughout the specification. In the drawings, the length, thickness, and the like of each component are illustrated to explain the present invention, and the present invention is not limited to the length, thickness, and the like described in the drawings.

In the present specification, "upper part" and "lower part" are defined based on the drawings, and "upper part" may be changed to "lower part" and "lower part" may be changed to "upper part" according to the viewpoint of the view, and "on" or What is referred to as "on" may include a case where other structures are interposed not only above but also in the middle.

In the present specification, "(meth)acrylic" may mean acrylic and/or methacrylic.

When describing the numerical range in the present specification, "X to Y" means X or more and Y or less (X≤ and ≤Y).

The inventor of the present invention is a carrier substrate as a re-peelable adhesive tape for temporarily fixing a panel for a light emitting display device, e.g., an organic light emitting device panel, to an adherend, e.g., a carrier substrate (e.g., a carrier glass substrate), and then peeling it again. A non-adhesive surface was formed on a part of the adhesive layer adhered to the side. Through this, the pressure-sensitive adhesive sheet was easily peeled off from the adherend by the air blowing process. In addition, by using the UV-curable adhesive layer as the adhesive layer, it is possible to suppress the occurrence of device defects and warpage because a heat treatment process is not required as in the adhesive layer including a conventional foam. In addition, by providing two types of adhesive layers having different peel strengths after UV curing, selective peeling was possible.

The releasable adhesive sheet of the present invention includes a base layer, a first adhesive layer formed on an upper surface of the base layer, and a second adhesive layer formed on a lower surface of the base layer, and among the lower surfaces of the second adhesive layer A non-adhesive layer surface is formed on some surfaces.

Preferably, the non-adhesive surface may be formed by a masking film.

Hereinafter, a releasable adhesive sheet according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 is a cross-sectional view of a releasable adhesive sheet according to an embodiment of the present invention. FIG. 2 is a plan view of a lower surface of a second adhesive layer in the releasable adhesive sheet of FIG. 1.

Referring to FIG. 1, the releasable adhesive sheet includes a base layer 100, a first adhesive layer 110 formed on the upper surface of the base layer 100, and a second adhesive layer formed on the lower surface of the base layer 100. 120 and a masking film 130 formed on the lower surface of the second adhesive layer 120.

In the releasable adhesive sheet, a non-adhesive surface is partially formed on the lower surface of the second adhesive layer 120 by the masking film 130.

In the case of attempting to re-peel the re-peelable adhesive sheet from the adherend, air is injected from the outside by the air blowing process. A conventional adhesive sheet having a foaming agent or a foaming layer can provide a starting point through which air can penetrate, but the bonding force between the adhesive layer and the adherend may be reduced, and since the foaming agent acts by heat, a heat treatment process is essential. Should be included. In addition, the conventional pressure-sensitive adhesive sheet made of only an adhesive layer has a problem in that it is difficult to provide a starting point through which air can penetrate. However, in the case of forming the adhesive layer in the form of a pattern spaced apart from each other in order to provide a flow path through which air can move, the adhesive strength to the adherend is not high, so it is difficult to achieve the original purpose of the adhesive sheet, and it is difficult to manufacture, so fairness may be degraded.

When air is supplied from the outside, the masking film makes it easy to provide a starting point where air can penetrate between the adherend and the adhesive sheet, and at the same time, it provides an appropriate space for air to be supplied so that the adhesive sheet can be easily peeled from the adherend. I can. In addition, since the masking film is formed only on a part of the lower surface of the second adhesive layer, the adhesive strength between the second adhesive layer and the adherend is also secured to some extent, so that the original purpose of the adhesive sheet can be easily achieved.

In one embodiment, the masking film is formed on the outer surface of the lower surface, which is the adhesion surface of the second adhesive layer, sufficient to provide a starting point through which air can penetrate. When the masking film is formed inside of the adherend of the second adhesive layer, the degree of bonding with the adherend may be weak, and it may be difficult to provide a starting point through which air can penetrate.

Each part of the releasable adhesive sheet of the present invention will be described in more detail.

Base layer

The base layer 100 is formed between the first adhesive layer 110 and the second adhesive layer 120, supports the first adhesive layer and the second adhesive layer, and can increase the mechanical strength of the releasable adhesive sheet. .

When the substrate layer 100 is adhered to the adherend and then peeled again, it is preferable to have a lower modulus or hardness than the adherend in order to suppress deformation and/or warpage of the adherend. In one embodiment, the base layer 100 may be a laminate of at least one of an optically transparent resin film and/or a metal film. The optically transparent resin film may include a polyester resin film such as polyethylene terephthalate and polyethylene naphthalate, but is not limited thereto. The metal film may include a film such as titanium or copper, but is not limited thereto.

The base layer 100 may have a thickness of 10 μm to 1 mm, specifically 12.5 μm to 125 μm, and more specifically 25 μm to 50 μm. Within the above range, it is easy to handle the pressure-sensitive adhesive sheet, and when the pressure-sensitive adhesive sheet is peeled from the adherend, the strength of the pressure-sensitive adhesive sheet can be maintained.

The base layer 100 is optically transparent, so that when the pressure-sensitive adhesive sheet is adhered, the adhesive state can be easily confirmed. In addition, the base layer 100 has a high transmittance to UV so that it is easy to use the UV-curable first adhesive layer and the second adhesive layer for the adhesive sheet. In one embodiment, the base layer may have a light transmittance of 50% or more, specifically 50% to 80% at a wavelength of 200 nm to 450 nm.

The base layer 100 may be colorless and optically transparent, but when the adhesive sheet is adhered to the adherend, the adhered state is recognized by the camera. In order to increase the recognition rate for the camera, the base layer 100 may be colored or may have a haze in a predetermined range.

In one embodiment, the base layer may use a green colored film or sheet as a colored film or sheet in order to increase the camera recognition rate. The green color may be implemented by adding a green dye or pigment to the composition for forming the base layer when preparing the base layer, but is not limited thereto.

In another embodiment, the base layer may have a haze of 20% or less, specifically 1% to 10%. In this range, it is possible to sufficiently check the deposition state by increasing the camera recognition rate. The substrate layer having the above-described haze may be implemented by a conventional method known to those skilled in the art. For example, it may be implemented by including organic particles, inorganic particles, and/or organic-inorganic hybrid particles in the base layer. Inorganic particles include at least one of zirconia, silica, and titania, and organic particles are at least one of (meth)acrylic particles including silicon particles, polymethyl methacrylate (PMMA) particles, etc. Including, the organic-inorganic hybrid particles may include core-shell type particles, but are not limited thereto. Preferably, by including organic particles such as silicon particles in the substrate layer, damage to the adherend can be prevented and compatibility with the resin for forming the substrate layer can be improved. For example, the base layer may include organic particles, inorganic particles, and/or organic-inorganic hybrid particles in an amount of 1% to 50% by weight, specifically 20% to 35% by weight of the base layer. In the above range, it is possible to increase the camera recognition rate.

Although not shown in FIG. 1, by forming a functional coating layer including a primer layer, etc. on at least one of the upper and lower surfaces of the substrate layer, it is possible to facilitate the formation of the first adhesive layer or the second adhesive layer on the substrate layer. have.

First adhesive layer and second adhesive layer

The first adhesive layer 110 and the second adhesive layer 120 are formed on the upper and lower surfaces of the base layer 100, respectively, so that the releasable adhesive sheet of the present invention can be a double-sided adhesive-type adhesive sheet. have.

The masking film 130 is formed only on the lower surface of the second adhesive layer 120 and is not formed on the upper surface of the first adhesive layer 110. The masking film also has a predetermined thickness and is formed only in part of the second adhesive layer. Therefore, in order to reduce the step difference according to the presence or absence of the formation of the masking film in the second adhesive layer, it may be preferable that the masking film be included in the form recessed in the second adhesive layer. Therefore, the modulus of the first adhesive layer and the second adhesive layer should be different from each other. The "modulus" means a storage modulus at 25°C.

In one embodiment, the modulus of the second adhesive layer and the modulus of the first adhesive layer may have a relationship of Equation 1:

[Equation 1]

G1> G2

(In Equation 1 above,

G1 is the modulus of the first adhesive layer,

G2 is the modulus of the second adhesive layer).

By having the relationship of the above formula (1), it is possible to easily laminate the masking film on the lower surface of the second adhesive layer, and while maintaining the strength of the adhesive sheet, it is possible to use the adhesive sheet even in the vacuum pressing process.

For example, the ratio of the modulus of the first adhesive layer to the modulus of the second adhesive layer (G1/G2) may be 2 or more, specifically 2 to 3. Within the above range, it is possible to easily laminate the masking film on the lower surface of the second adhesive layer, and while maintaining the strength of the adhesive sheet, it is possible to use the adhesive sheet in a vacuum pressing process.

For example, the modulus of the first adhesive layer may be 0.1 MPa or more, specifically 0.1 MPa to 0.15 MPa, and more specifically 0.1 MPa to 0.12 MPa. In the above range, the shape of the pressure-sensitive adhesive sheet can be maintained even by vacuum compression when bonding the adherend.

For example, the modulus of the second adhesive layer may be 0.04 MPa or more, specifically 0.04 MPa to 0.06 MPa, and more specifically 0.04 MPa to 0.05 MPa. In the above range, the masking film may be well depressed and laminated in the second adhesive layer, and a step difference due to the formation of the masking film may be reduced.

The first adhesive layer and the second adhesive layer have different adherends, and when the adhesive sheet is irradiated with UV when the adhesive sheet is applied, the panel is separated from the first adhesive layer and the second adhesive layer must be adhered on the carrier glass. . Therefore, the first adhesive layer and the second adhesive layer must have different adhesive strength after UV irradiation.

The "adhesive force" refers to the peel strength when UV irradiation is applied to the first adhesive layer or the second adhesive layer and peeled at a peeling angle of 180° at a peel rate of 300 mm/min at 25° C. for an adherend, for example, an alkali-free glass plate. . Through this, the pressure-sensitive adhesive sheet may have different adhesive strength between the first adhesive layer and the second adhesive layer after UV curing, so that selective peeling may be possible.

Specifically, the adhesive force after UV irradiation of the second adhesive layer and the adhesive force after UV irradiation of the first adhesive layer may have a relationship of Equation 2 below:

[Equation 2]

PS2> PS1

(In Equation 2 above,

PS1 is the adhesion of the first adhesive layer after UV irradiation,

PS2 is the adhesion of the second adhesive layer after UV irradiation).

By having the relationship of the above formula 2, the pressure-sensitive adhesive sheet can be used as a double-sided pressure-sensitive adhesive sheet for temporary fixing of panels.

For example, the ratio (PS2/PS1) of the adhesive force after UV irradiation of the first adhesive layer to the adhesive force after UV irradiation of the second adhesive layer (PS2/PS1) may be 2.4 or more, specifically 2.4 to 6.0. In the above range, each of the first adhesive layer and the second adhesive layer may be formed as a UV-curable adhesive layer.

For example, the adhesive force of the first adhesive layer after UV irradiation may be 4 gf/in or more, specifically 4 gf/in to 12 gf/in, and more specifically 4 gf/in to 10 gf/in. In the above range, the adhesion of the first adhesive layer to the adherend is low, and thus fairness can be secured.

For example, the adhesive force of the second adhesive layer after UV irradiation may be 11 gf/in or more, specifically 11 gf/in to 30 gf/in, and more specifically 11 gf/in to 24 gf/in. In the above range, after UV curing, the panel may be first separated, and then the effect of selective peeling of removing the tape from the glass through air blowing may be obtained.

Each thickness of the first adhesive layer and the second adhesive layer may be appropriately adjusted according to the use of the adhesive sheet, the thickness of the base layer, and the like. For example, the thickness of the first adhesive layer may be 10 μm to 30 μm, specifically 10 μm to 20 μm. The thickness of the second adhesive layer may be the same as or different from the thickness of the first adhesive layer, and the thickness may be 20 μm to 80 μm, specifically 20 μm to 40 μm. In the above range, it is easy to manufacture the pressure-sensitive adhesive sheet, and it is possible to secure a peeling force on the adherend.

The first adhesive layer and the second adhesive layer are not particularly limited, but may be active energy ray-curable adhesive layers. In one embodiment, the first adhesive layer and the second adhesive layer may be a UV-curable (meth)acrylic adhesive layer.

The "UV curing" means for irradiating a first adhesive layer, second adhesive layer wavelength of 200nm and the light intensity of 300mJ / cm ² to 3,000mJ / cm ² under the conditions of about 450nm.

The masking film 130 is formed only on the lower surface of the second adhesive layer 120 and is not formed on the upper surface of the first adhesive layer 110. The masking film is formed on the lower surface of the second adhesive layer, the masking film also has a certain thickness, and is formed only in part of the second adhesive layer. Therefore, in order to eliminate the step difference according to the formation of the masking film in the second adhesive layer, the viscosity of the composition for forming the first adhesive layer and the second adhesive layer must be adjusted. The viscosity refers to the viscosity measured at 25°C with respect to the composition for an adhesive layer.

In one embodiment, the viscosity of the composition for the second adhesive layer and the viscosity of the composition for the first adhesive layer may have a relationship of Equation 3:

[Equation 3]

V1> V2

(In Equation 3 above,

V1 is the viscosity of the composition for the first adhesive layer,

V2 is the viscosity of the composition for the second adhesive layer).

By having the relationship of the above formula (3), it is possible to easily laminate the masking film on the lower surface of the second adhesive layer, and while maintaining the strength of the pressure-sensitive adhesive sheet, it is possible to increase the re-peelability by the air blowing process.

For example, the ratio (V1/V2) of the viscosity of the composition for the first adhesive layer to the viscosity of the composition for the second adhesive layer (V1/V2) may be 2 or more, specifically 2 to 3. In the above range, each of the first adhesive layer and the second adhesive layer may be formed as a UV-curable adhesive layer.

Each of the first adhesive layer and the second adhesive layer may be a UV-curable (meth)acrylate-based adhesive layer. As described above, the modulus, adhesion, and viscosity of each of the first adhesive layer and the second adhesive layer can be achieved by adjusting the content and/or type of each component included in the adhesive layer composition. Hereinafter, a composition for an adhesive layer for forming the first adhesive layer and the second adhesive layer will be described.

The adhesive layer composition is a UV-curable (meth)acrylic adhesive layer, which is cured for a specific wavelength at a continuous wavelength emitted from a metal halide lamp or a high-pressure mercury lamp, or a wavelength emitted from a UV LED at 200 nm to 450 nm with an emission wavelength of 200 nm to 450 nm. It may include an adhesive layer.

The composition for an adhesive layer includes a UV-curable adhesive binder resin, a curing agent, and a photoinitiator. The composition for an adhesive layer may further include at least one of a filler and a UV-reactive oligomer.

The UV curable adhesive binder resin may be a (meth)acrylic resin, a silicone resin, or the like, but preferably may include a (meth)acrylic resin in consideration of ease of supply and demand and UV curability. In one embodiment, the (meth)acrylic resin may be a resin in which 10% to 50% by weight of a (meth)acrylate functional group is added to the side chain. The curing agent may be a conventional curing agent such as an isocyanate curing agent or an epoxy curing agent, and may be appropriately selected and used according to the type of UV curable adhesive binder resin. The photoinitiator may be a conventional type such as a phosphorus photoinitiator. The filler is included in the adhesive layer composition to increase the modulus of the adhesive layer, and at least one of an organic filler, an inorganic filler, or a hybrid filler may be used. In one embodiment, the organic filler may use particles formed of at least one of silicone particles and polymethyl (meth)acrylate. The UV-reactive oligomer increases the curing rate of the adhesive layer during UV curing and can be used in a type having a lower molecular weight compared to the UV-curable adhesive binder resin.

In one embodiment, the composition for the first adhesive layer contains 1 part by weight to 10 parts by weight of a curing agent, 0.1 part by weight to 5 parts by weight of a photoinitiator, and 10 parts by weight to 30 parts by weight of a filler, based on 100 parts by weight of the UV-curable adhesive binder resin. I can. In the above range, the modulus of the first adhesive layer and the adhesive force after UV irradiation can be easily reached.

The composition for the first adhesive layer may further include 1 part by weight to 10 parts by weight of a UV-reactive oligomer based on 100 parts by weight of the UV-curable adhesive binder resin.

In one embodiment, the composition for the second adhesive layer is based on 100 parts by weight of the UV-curable adhesive binder resin, 0.1 parts by weight to 10 parts by weight of a curing agent, 0.1 parts by weight to 5 parts by weight of a photoinitiator, 10 parts by weight to 30 parts by weight of a UV reactive oligomer Can include. In the above range, the modulus of the second adhesive layer and the adhesive force after UV irradiation can be easily reached.

The composition for the second adhesive layer may further include 10 parts by weight to 30 parts by weight of a filler based on 100 parts by weight of the UV-curable adhesive binder resin.

In one embodiment, the composition for an adhesive layer may not include a foam or a foaming agent having foamability by heating.

Masking film

The masking film 130 is formed only on a part of the second adhesive layer 120 to provide a non-adhesive surface to a part of the second adhesive layer 120. Through this, when air is injected between the adherend and the adhesive sheet, it provides a starting point through which air can penetrate, and at the same time, it ensures the adhesion between the adherend and the second adhesive layer after UV irradiation, thereby achieving both re-peelability and adhesiveness. To achieve.

In particular, in the pressure-sensitive adhesive sheet of the present invention, since the masking film exists as an independent layer separate from the second adhesive layer, the adhesive force of the second adhesive layer to the adherend is not affected and re-peelability is obtained.

The pressure-sensitive adhesive sheet of FIG. 1 is obtained by applying a masking film to form a non-adhesive surface on a part of the second adhesive layer. However, the present invention is not limited thereto, and a known means not limited to the masking film may be applied if a non-adhesive surface can be formed on the second adhesive layer. However, the masking film is a film material, as described below, and is advantageous for lifting by air blowing without affecting the adhesion of the second adhesive layer to the adherend, providing a non-adhesive surface and may be preferable for re-peelability. have.

The masking film 130 is formed on the second adhesive layer 120 to cover part of the adhesive force of the second adhesive layer. In one embodiment, as shown in FIG. 1, the masking film may be formed in a state that is recessed in the second adhesive layer. In another embodiment, the masking film may be formed on the lower surface of the second adhesive layer without being depressed in the second adhesive layer.

The area ratio S3/S2 occupied by the masking film 130 among the lower surfaces of the second adhesive layer 130 (S2 is the area of the lower surface of the second adhesive layer, S3 is the total area of the masking film formed on the second adhesive layer) It may be 0.01 to 0.5, specifically 0.06 to 0.3, more specifically 0.14 to 0.31. Within the above range, it is possible to achieve both re-peelability and adhesion of the second adhesive layer to the adherend during the air blowing process. The "area of the lower surface of the second adhesive layer" means the total sum of the area of the portion of the second adhesive layer where the masking film is not formed and the area of the portion of the second adhesive layer where the masking film is formed.

The masking film 130 is formed on the outer surface of the adherend surface of the second adhesive layer to be sufficient to provide a starting point through which air can penetrate. When the masking film is formed inside of the adherend of the second adhesive layer, the degree of bonding with the adherend may be weak, and it may be difficult to provide a starting point through which air can penetrate.

In one embodiment, when the second adhesive layer has a shape having an edge portion including an angled portion, the masking film may be formed to include an edge portion. Through this, it is possible to provide a starting point through which air can penetrate when air blowing is introduced from the outside.

In this regard, it will be described with reference to FIG. 2. FIG. 2 is a plan view of a lower surface of a second adhesive layer in the releasable adhesive sheet of FIG. 1.

Referring to FIG. 2, when the adhesive sheet has a rectangular shape, the adhesive sheet has a lower surface 120A of the second adhesive layer, and the masking film 130 is a corner portion of the lower surface 120A of the second adhesive layer. It is formed only. The masking film 130 is not formed on a part of the outer surface of the second adhesive layer 120A. Through this, it is possible to sufficiently provide a starting point through which air can penetrate during the air blowing process.

The masking film may be formed in a triangular shape. However, the present invention is not limited thereto, and in addition to a triangular shape, N (N is an integer of 4 to 10) such as a square, a rectangle, and a pentagon may be included.

Referring to FIG. 2, when the second adhesive layer has a rectangular shape, a length c of an area without a masking film among one side of the rectangle and a length d of an area without a masking film among the other side adjacent to one side of the rectangle are They are different, and the ratio of d to c may be greater than 1, for example from 1.4 to 20. In the above range, it is possible to smoothly move the air during the air blowing process, and can also be adhered to the adherend.

Referring back to FIG. 2, when the pressure-sensitive adhesive sheet has a rectangular shape, an angled corner may be formed on the outer surface of the masking film.

The material of the masking film 130 is not particularly limited as long as the lower surface of the masking film is non-adhesive so as to provide a non-adhesive surface to a part of the second adhesive layer. For example, the masking film 130 may include an optically transparent resin film, and specifically, may include a polyester resin film such as polyethylene terephthalate and polyethylene naphthalate, but is not limited thereto.

The masking film 130 may have a thickness of 9 μm to 100 μm, specifically 9 μm to 50 μm, and more specifically 9 μm to 38 μm. In the above range, it may be applied as a masking film, and defects due to formation of a step compared to the second adhesive layer may be prevented.

The masking film 130 may have a transmittance of 50% or more, for example, 50% to 90%, to an active energy ray, for example, UV. In the above range, when the first adhesive layer and the second adhesive layer are UV-curable (meth)acrylic adhesive layers, it is possible to increase the manufacturing processability of the first adhesive layer and the second adhesive layer.

Hereinafter, an adhesive sheet according to another embodiment of the present invention will be described with reference to FIG. 3. 3 is a plan view of a lower surface of a second adhesive layer in an adhesive sheet according to another embodiment of the present invention.

Referring to FIG. 3, a masking film 130 is formed on a lower surface of the second adhesive layer 120A of the adhesive sheet. The masking film 130 is formed on a corner of the lower surface of the second adhesive layer 120A, and is not formed on a part of the outer surface of the second adhesive layer 120A. It is substantially the same as the pressure-sensitive adhesive sheet of FIG. 1 except that the edge portion of the masking film 130 is formed in a curved surface.

Compared to the case where the masking film has an angled corner shape as shown in FIG. 2, when the corner of the masking film is curved as shown in FIG. 3, air penetration by the air blowing process may be more easily performed.

Referring to Figure 4, a re-releaseable pressure-sensitive adhesive sheet according to another embodiment of the present invention will be described. 4 is a cross-sectional view of a releasable pressure-sensitive adhesive sheet according to another embodiment of the present invention.

Referring to FIG. 4, the adhesive sheet includes a base layer 100, a first adhesive layer 110, a second adhesive layer 120, a masking film 130, and a third adhesive layer 140. It is substantially the same as the adhesive sheet of FIG. 1 except that the third adhesive layer 140 is additionally formed between the second adhesive layer 120 and the masking film 130.

The third adhesive layer 140 may be formed between the masking film 130 and the second adhesive layer 120 to provide an effect of preventing the masking film from being separated from the second adhesive layer during air blowing.

The third adhesive layer 140 may have a thickness of 10 μm to 50 μm, specifically 10 μm to 30 μm, and more specifically 20 μm to 30 μm. In the above range, it is possible to provide an effect of preventing separation of the masking film.

The third adhesive layer 140 may include a NON-UV type adhesive layer. Unlike the above-described UV-type adhesive layer, the "NON-UV-type adhesive layer" refers to an adhesive layer formed of a composition for an adhesive layer that can be cured by a method other than UV. In the present invention, the second adhesive layer 120 is a UV-curable adhesive layer, whereas the third adhesive layer 140 is a NON-UV-type adhesive layer, thereby preventing the adhesive strength of the adhesive layer from decreasing due to UV irradiation. You can get it.

In one embodiment, the composition for forming the third adhesive layer may include an adhesive binder resin that is not cured by UV and the above-described curing agent. For example, it may include 0.1 parts by weight to 10 parts by weight of a curing agent based on 100 parts by weight of the adhesive binder resin not cured by UV.

Hereinafter, the manufacturing method of the releasable pressure-sensitive adhesive sheet of the present invention will be described.

The releasable adhesive sheet of the present invention coats the composition for the first adhesive layer on the upper surface of the substrate layer, coats the composition for the second adhesive layer on the lower surface of the substrate layer, and laminates a masking film on the coating layer. , Dried and then punched into a predetermined size.

In addition, the releasable adhesive sheet of the present invention coats the composition for the first adhesive layer on the upper surface of the base layer, coats the composition for the second adhesive layer on the lower surface of the base layer, and then dries a predetermined size. It can be produced by punching and laminating a masking film on the coating layer.

In addition, each step in the method of forming the releasable pressure-sensitive adhesive sheet of the present invention may be changed, and additional processes known to those skilled in the art may be added.

Hereinafter, a method of using the releasable pressure-sensitive adhesive sheet of the present invention will be described.

The releasable pressure-sensitive adhesive sheet of the present invention can be applied to a process of temporarily fixing a light emitting device panel including an organic light emitting device to a carrier glass.

In one embodiment, the method of using the releasable pressure-sensitive adhesive sheet of the present invention is after placing the re-releaseable pressure-sensitive adhesive sheet of the present invention on one side of a carrier glass, and disposing the light emitting device panel on the re-releaseable pressure-sensitive adhesive sheet. At this time, the first adhesive layer was directed toward the light emitting device panel, the first adhesive layer and the second adhesive layer of the releasable adhesive sheet were cured with active energy rays, and the light emitting device panel was removed from the re-releaseable adhesive sheet. And separating the releasable adhesive sheet from the carrier glass.

In the step of irradiating the active energy ray, the first adhesive layer and the second adhesive layer are cured to facilitate peeling from the light emitting device panel and the carrier glass. For example, the active energy ray irradiation may include irradiation with a wavelength of 200 nm to 450 nm and an intensity of 300 m J/cm ² or more, but is not limited thereto.

The step of separating the releasable pressure-sensitive adhesive sheet from the carrier glass may be performed by an air blowing process. Specifically, the air blowing process may include a process of injecting air between the carrier glass and the releasable adhesive sheet, for example, an air knife process, but is not limited thereto.

Hereinafter, the present invention will be described in more detail through examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Preparation Example 1: Preparation of the composition for the first adhesive layer

2 parts by weight of AK-DA (Aekyung Chemical) as an isocyanate-based curing agent, 25 parts by weight of KMP-601 (Shin-Etsu) as a silicone particle and 1.52 parts by weight of IRGACURE 819 (Ciba) as a photoinitiator compared to 100 parts by weight of UV-curable adhesive binder resin A UV curable first adhesive layer composition containing was prepared. As the UV-curable adhesive binder resin, a polymer resin (Mw 550,000) in which 35 wt% of an acrylate functional group was added as a side chain to the main chain of an acrylic base resin was used.

Preparation Example 2: Preparation of the composition for the first adhesive layer

In Preparation Example 1, 3.8 parts by weight of M150 (Miwon Specialty Chemical) was further added as a UV-reactive oligomer to prepare a composition for a first adhesive layer.

Preparation Example 3: Preparation of the composition for the second adhesive layer

Contains 0.8 parts by weight of AK-DA (Aekyung Chemical Co., Ltd.), 25 parts by weight of UV-reactive oligomer M150 (Miwon Specialty Chemical Co., Ltd.), and 1.6 parts by weight of IRGACURE 819 (Ciba Co., Ltd.) as a photoinitiator compared to 100 parts by weight of UV-curable adhesive binder resin. One UV-curable second adhesive layer composition was prepared. As the photocurable adhesive binder resin, a polymer resin (Mw 550,000) in which 40 wt% of an acrylate functional group was added as a side chain to the main chain of an acrylic base resin was used.

Preparation Example 4: Preparation of the composition for the second adhesive layer

In Preparation Example 3, 20 parts by weight of silicone particles KMP-601 (Shin-Etsu) were added to prepare a composition for a second adhesive layer.

Preparation Example 5: Preparation of the composition for the third adhesive layer

A composition for a non-UV curable third adhesive layer containing 0.8 parts by weight of an isocyanate-based curing agent AK-DA (Aekyung Chemical Co., Ltd.) relative to 100 parts by weight of a non-UV adhesive binder resin was prepared. As the adhesive binder resin, a polymer resin (Mw 550,000) in which 40 wt% of an acrylate functional group was added as a side chain to the main chain of an acrylic base resin was used.

[Physical property evaluation for Preparation Examples 1 to 4]

The viscosity of the composition for the first adhesive layer of Preparation Examples 1 to 2 was measured at 25°C. Specifically, the viscosity was measured by the Rheometer method (ASTM D4440).

The composition for the first adhesive layer of Preparation Examples 1 to 2 was applied to a polyethylene terephthalate (PET) film (thickness: 50 μm, product name: SH34, manufacturer: SKC) to a thickness of 20 μm and dried at 120° C. for 3 minutes. A laminate having a first adhesive layer having a thickness of 20 μm was prepared.

For the adhesive layer compositions of Preparation Examples 3 to 4, the viscosity was measured in the same manner as described above, and a laminate having an adhesive layer having a thickness of 20 μm was prepared in the same manner as described above.

Using the prepared laminate, the storage modulus of Table 1 below and adhesion after UV irradiation were evaluated.

(1) Storage Modulus: Among the laminates prepared above, a plurality of adhesive layers cut into circular specimens having a diameter of 8 mm x 20 μm were stacked into 50 layers to prepare a specimen for measuring a storage modulus. A storage modulus measuring device (TA Instruments, ARES-G2) was used to measure a measurement temperature of 0° C. to 70° C., a temperature increase rate of 10° C./min, and a measurement frequency of 0.796 Hz by a frequency sweep test. Of these, the value at 25°C was taken.

(2) Adhesion after UV irradiation: The prepared laminate was cut into a length of 100 mm x 1 inch in width, and the adhesive layer surface was reciprocally attached to an alkali-free glass plate with a 2 kg roller twice to prepare a specimen for measuring adhesion. UV was irradiated on the specimen with a metal halide lamp at an intensity of ^{300 mJ/cm 2.} Using an adhesion measuring device (CHEMI LAB, SurTA), the peel strength when the tape was peeled from the alkali-free glass plate was measured at a peeling angle of 180°, a peeling temperature of 25° C., and a peeling speed of 300 mm/min.

First adhesive layer Second adhesive layer Manufacturing Example 1 Manufacturing Example 2 Manufacturing Example 3 Manufacturing Example 4 Viscosity (Pa.s) 26,046 21,270 8,682 10,635 Storage modulus (MPa) 0.12 0.1 0.04 0.05 Adhesion after UV irradiation (gf/in) 10 4 24 11

Example 1

As a base layer, the composition for the first adhesive layer of Preparation Example 1 was applied to the upper surface of a polyethylene terephthalate (PET) film (thickness: 50 μm, SH34, SKC) to a predetermined thickness and dried to form a coating film for the first adhesive layer. Formed. The composition for the second adhesive layer of Preparation Example 3 was applied to the lower surface of the PET film to a predetermined thickness, and a coating film for the second adhesive layer was formed.

The laminate of the coating film for the first adhesive layer / the base layer / the coating film for the second adhesive layer was punched into a square shape having a length of 30 mm x a width of 30 mm as shown in FIG. 2. As a masking film, a polyethylene terephthalate film (thickness: 38 μm, SM-38D, UNITIKA) was cut into the shape of FIG. 2, and then bonded to the lower surface of the coating film for the second adhesive layer as shown in FIG. 2 to attach an adhesive sheet. Was prepared.

Examples 2 to 7

In Example 1, a pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that the size and/or shape and/or the adhesive layer composition of the masking film was changed as shown in Table 2 below.

Example 8

As a base layer, the composition for the first adhesive layer of Preparation Example 2 was applied to the upper surface of a polyethylene terephthalate (PET) film (thickness: 50 μm, SH34, SKC) to a predetermined thickness and dried to form a coating film for the first adhesive layer. Formed. The composition for the second adhesive layer of Preparation Example 4 was applied to the lower surface of the PET film to a predetermined thickness, and a coating film for the second adhesive layer was formed. As shown in FIG. 4, the composition for a third adhesive layer of Preparation Example 5 was applied to a portion of the lower surface of the coating film for the second adhesive layer to a predetermined thickness, and a coating film for the third adhesive layer was formed.

The laminate of the coating film for the first adhesive layer / the base layer / the coating film for the second adhesive layer / the coating film for the third adhesive layer was punched into a square shape having a length of 30 mm x a width of 30 mm as shown in FIG. 4. As a masking film, a polyethylene terephthalate film (thickness: 38 μm, SM-38D, UNITIKA) was cut into the shape of FIG. 2, and then bonded to the lower surface of the coating film for the third adhesive layer as shown in FIG. 4 to attach an adhesive sheet. Was prepared.

Comparative Example 1

In Example 5, an adhesive sheet was prepared in the same manner as in Example 5, except that a masking film was not formed on the lower surface of the second adhesive layer.

The following re-peelability was evaluated for the pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples, and the results are shown in Table 2 below.

Re-peelability: The prepared laminate was cut into length x width (100 mm x 1 inch), and the second adhesive layer surface was reciprocated twice with a 2 kg roller on an alkali-free glass plate to prepare a specimen. After irradiating the prepared specimen with UV with a metal halide lamp at ^{an intensity of 300 m J/cm 2} , air was sprayed with an air gun at a pressure of 0.4 MPa and an angle of 45 ˚ for 2 seconds to measure whether the laminate was peeled from the alkali-free glass plate. When the laminate was peeled from the alkali-free glass plate, it was evaluated as "good", and if it was not peeled off, it was evaluated as "not possible."

Example Comparative example One 2 3 4 5 6 7 8 One Masking film shape triangle triangle triangle triangle triangle triangle triangle triangle - First adhesive layer Manufacturing Example 1 Manufacturing Example 1 Manufacturing Example 1 Manufacturing Example 1 Manufacturing Example 2 Manufacturing Example 2 Manufacturing Example 2 Manufacturing Example 2 Manufacturing Example 2 Second adhesive layer Manufacturing Example 3 Manufacturing Example 3 Manufacturing Example 3 Manufacturing Example 3 Manufacturing Example 4 Manufacturing Example 4 Manufacturing Example 4 Manufacturing Example 4 Manufacturing Example 4 3rd adhesive layer - - - - - - - Manufacturing Example 5 - Fig. 2 a 5mm 5mm 11mm 8mm 5mm 5mm 11mm 8mm - Figure 2b 14.5mm 12.5mm 12.5mm 12.5mm 14.5mm 12.5mm 12.5mm 12.5mm - Fig. 2c 1mm 5mm 5mm 5mm 1mm 5mm 5mm 5mm - Figure 2 d 20mm 20mm 8mm 14mm 20mm 20mm 8mm 14mm - Area ratio 0.16 0.14 0.31 0.22 0.16 0.14 0.31 0.22 - Re-peelability Good Good Good Good Good Good Good Good Impossible

As shown in Table 2 above, in the re-peelable adhesive sheet of the present invention, the re-peelable pressure-sensitive adhesive sheet was easily peeled off from the carrier glass by the air blowing process when evaluating the re-peelability.

On the other hand, Comparative Example 1 without a masking film had poor re-peelability.

Simple modifications or changes of the present invention can be easily implemented by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (15)

A base layer, a first adhesive layer formed on the upper surface of the base layer, and a second adhesive layer formed on the lower surface of the base layer,
Some surfaces of the second adhesive layer are non-adhesive layer surfaces, the re-peelable adhesive sheet. The releasable pressure-sensitive adhesive sheet according to claim 1, wherein the non-adhesive layer surface is formed by a masking film. The releasable pressure-sensitive adhesive sheet according to claim 2, wherein the masking film is formed in a state that is recessed in the lower surface of the second adhesive layer. The method of claim 2, wherein the area ratio of the total area of the masking film to the area of the lower surface of the second adhesive layer S3/S2 (S2 is the area of the lower surface of the second adhesive layer, and S3 is the total area of the masking film. Area) is 0.01 to 0.5, the re-peelable pressure-sensitive adhesive sheet. The releasable pressure-sensitive adhesive sheet according to claim 4, wherein the area ratio S3/S2 is 0.14 to 0.31. The releasable pressure-sensitive adhesive sheet according to claim 2, wherein the masking film is formed at a corner of an outer surface of a lower surface of the second adhesive layer. The method of claim 6, wherein the masking film has an angled corner, the releasable pressure-sensitive adhesive sheet. The releasable pressure-sensitive adhesive sheet according to claim 2, wherein the masking film has a transmittance to UV of 50% or more. The releasable pressure-sensitive adhesive sheet according to claim 1, wherein the base layer comprises a colored film. The releasable pressure-sensitive adhesive sheet according to claim 1, wherein the base layer has a haze of 20% or less. According to claim 1, The first adhesive layer and the second adhesive layer is that the storage modulus is different from each other at 25 ℃, the releasable pressure-sensitive adhesive sheet. According to claim 1, The first adhesive layer and the second adhesive layer will have different adhesive strength after UV irradiation, the re-peelable adhesive sheet. According to claim 1, The first adhesive layer and the second adhesive layer is each comprising a UV-curable (meth)acrylic adhesive layer, the re-peelable adhesive sheet. The releasable adhesive sheet according to claim 2, wherein a third adhesive layer is further formed between the second adhesive layer and the masking film. The releasable adhesive sheet according to claim 14, wherein the third adhesive layer comprises a NON UV curable (meth)acrylic adhesive layer.

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