KR102362764B1 - Repeelable adhesive sheet - Google Patents

Abstract

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, and a masking film is formed on some of the lower surfaces of the second adhesive layer, , The second adhesive layer is provided with a re-peelable adhesive sheet, wherein the value of Formula 1 between the adhesive force before UV irradiation and the adhesive force after UV irradiation is 84% to 99%.

Description

Re-peelable adhesive sheet {REPEELABLE ADHESIVE SHEET}

The present invention relates to a releasable pressure-sensitive adhesive sheet. More particularly, the present invention relates to a re-peelable pressure-sensitive adhesive sheet that enables selective peeling after UV curing and can increase re-peelability during peeling by an air blowing process.

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

The double-sided adhesive tape has adhesive layers formed on the upper and lower surfaces of the base layer, respectively, so that the OLED panel and the carrier glass can be fixed at the same time. On the other hand, after the fixing process is completed, the double-sided adhesive tape should 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 while a foaming process occurs by heating causes the adhesive force to drop after heating is used. This is the principle that the foam contained in the pressure-sensitive adhesive layer is separated from the carrier glass due to the lowering of the adhesive force by foaming upon heating.

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

Background art of the present invention is disclosed in Korean Patent Publication No. 2009-0080073 and the like.

It is an object of the present invention to provide a re-peelable pressure-sensitive 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 adhesive layers having different peel strengths after UV curing.

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

The re-peelable adhesive sheet of the present invention includes 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, of the lower surface of the second adhesive layer A masking film is formed on some surfaces, and the value of the following formula 1 between the adhesive force before UV irradiation and the adhesive force after UV irradiation of the second adhesive layer is 84% to 99%:

[Equation 1]

Decrease rate of adhesion = ｜PS2 - PS1｜/ PS1 x 100

(In Equation 1 above,

PS1 is the adhesive strength of the second adhesive layer before UV irradiation,

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

In one embodiment, the masking film may be formed in a depressed state 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 in the corner portion of the outer surface of the lower surface of the second adhesive layer.

In one embodiment, the masking film may have angled corners.

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

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 strengths after UV irradiation.

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, which 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 adhesive layers having different peel strengths after UV curing.

The present invention provides a re-peelable pressure-sensitive 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 pixel defects and warpage caused by the heat treatment process.

1 is a cross-sectional view of a re-peelable 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 re-peelable adhesive sheet of FIG. 1 .
3 is a plan view of the lower surface of the second adhesive layer in the adhesive sheet according to another embodiment of the present invention.
4 is a cross-sectional view of a re-peelable pressure-sensitive adhesive sheet according to another embodiment of the present invention.

With reference to the accompanying drawings, the present invention will be described in detail so that those skilled in the art can easily carry out the present invention by way of example. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification. In the drawings, the length, thickness, etc. of each component are shown for explaining the present invention, and the present invention is not limited to the length, thickness, etc. described in the drawings.

In this specification, "upper" and "lower" are defined based on the drawings, and depending on the perspective of the city, "upper" may be changed to "lower" and "lower" to "upper", and "on" or What is referred to as “on” may include cases where other structures are interposed in the middle as well as immediately above. On the other hand, "directly on" or "directly on" means that other structures are not interposed therebetween.

As used herein, “(meth)acryl” may mean acryl and/or methacrylic.

When describing a 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 re-peelable adhesive tape for temporarily fixing a panel for a light emitting display device, for example, an organic light emitting device panel, to an adherend, for example, a carrier substrate (eg, a carrier glass substrate) and then peeling the carrier substrate. A non-adhesive surface was formed on a part of the adhesive layer adhered to the side. Through this, it was made easy to re-peel the adhesive sheet from the adherend by the air blowing process. In addition, by using the UV-curable adhesive layer as the adhesive layer, there is no need for a heat treatment process as in the conventional adhesive layer including a foam, and thus device defects and warpage can be suppressed.

The re-peelable adhesive sheet of the present invention includes 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, of the lower surface of the second adhesive layer A non-adhesive surface is formed on some surfaces. Preferably, the non-tacky surface may be formed by a masking film.

Hereinafter, a re-peelable 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 re-peelable 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 re-peelable adhesive sheet of FIG. 1 .

Referring to FIG. 1 , the re-peelable 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 (masking film) 130 formed on the lower surface of the second adhesive layer (120).

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

When the re-peelable pressure-sensitive adhesive sheet is to be peeled again from the adherend, air is injected from the outside by an air blowing process. Conventional pressure-sensitive adhesive sheets having a foaming agent or foaming layer can provide a starting point through which air can penetrate, but the bonding strength between the pressure-sensitive adhesive layer and the adherend may be reduced, and the foaming agent acts by heat, so a heat treatment process is essential should be included In addition, the conventional pressure-sensitive adhesive sheet made of only the pressure-sensitive adhesive layer has a problem in that it is difficult to provide a starting point through which air can penetrate. However, when the adhesive layers are formed in a pattern spaced apart from each other to provide a flow path through which the air can move, the adhesion 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, which may lower fairness.

The masking film provides a starting point for air to penetrate between the adherend and the adhesive sheet when air is supplied from the outside, and at the same time provides an appropriate space to which air is supplied, so that the adhesive sheet can be easily peeled off from the adherend. . In addition, the masking film is formed only on a portion of the lower surface of the second adhesive layer, thereby securing a certain amount of adhesive force between the second adhesive layer and the adherend, 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 adherend surface of the second adhesive layer, sufficient to provide a starting point through which air can penetrate. When the masking film is formed on the inside of the adherend surface 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 re-peelable adhesive sheet of this invention is demonstrated 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 110 and the second adhesive layer 120, and is a releasable adhesive sheet. Mechanical strength can be increased.

The base layer 100 preferably has a lower modulus or hardness than the adherend in order to suppress deformation and/or warpage of the adherend when it is peeled again after being adhered to the adherend. In one embodiment, the base layer 100 may be a laminate of one or more of an optically transparent resin film and/or a metal film. The optically transparent resin film may include, but is not limited to, a polyester-based resin film such as polyethylene terephthalate or polyethylene naphthalate. The metal film may include, but is not limited to, films such as titanium and copper.

The base layer 100 may have a thickness of 10 μm to 1 mm, specifically 12.5 μm to 125 μm, and more specifically 23 μm to 50 μm. Within the above range, the pressure-sensitive adhesive sheet is easy to handle, and the strength of the pressure-sensitive adhesive sheet can be maintained when the pressure-sensitive adhesive sheet is peeled off from the adherend.

Since the base layer 100 is optically transparent, when the pressure-sensitive adhesive sheet is attached to the adherend, it is possible to easily check the adhesion state. In addition, the base layer 100 has a high light 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.

On the other hand, when the pressure-sensitive adhesive sheet is adhered to the adherend, the adherend state is recognized by the camera. In order to increase the recognition rate of 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 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 the base layer is manufactured, but is not limited thereto.

In another embodiment, the base layer may have a haze of 20% or less, specifically 1% to 10%. Within the above range, it is possible to sufficiently confirm the deposition state by increasing the camera recognition rate. The base 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. The inorganic particles include at least one of zirconia, silica, and titania, and the organic particles include at least one of (meth)acrylic particles including silicon particles, polymethyl methacrylate (PMMA) particles, and the like. and, the organic-inorganic hybrid particles may include, but are not limited to, core-shell-type particles. Preferably, by including organic particles such as silicon particles in the base layer, damage to the adherend can be prevented and compatibility with the resin for forming the base layer can be improved. For example, the base layer may contain organic particles, inorganic particles, and/or organic-inorganic hybrid particles in an amount of 1 wt% to 50 wt%, specifically 20 wt% to 35 wt% of the base layer. Within the above range, it is possible to increase the camera recognition rate.

Although not shown in FIG. 1, a functional coating layer including a primer layer, etc. is formed on at least one of the upper surface and the lower surface of the base layer, thereby facilitating the formation of the first adhesive layer or the second adhesive layer on the base layer. have.

The first adhesive layer and the 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 re-peelable adhesive sheet of the present invention can be a double-sided pressure-sensitive adhesive sheet. have.

A masking film 130 is formed on a portion of the lower surface of the second adhesive layer 120 .

The masking film 130 is bonded to the second adhesive layer by the adhesive force of the second adhesive layer to the masking film. The adhesive force of the second adhesive layer is reduced in the subsequent UV irradiation process. Therefore, the masking film can be adhered to and maintained on the second adhesive layer before UV irradiation only when the adhesive force before UV irradiation and the adhesive force after UV irradiation of the second adhesive layer are adjusted, and the masking film is properly bonded to the second adhesive layer even after UV irradiation and the masking film may be maintained on the second adhesive layer even by an air blowing process after UV irradiation.

The second adhesive layer 120 has a value of Equation 1 below 84% to 99%. Specifically, the value of Equation 1 below may be specifically 85.0% to 97.5%. In the above range, the masking film can be adhered to and maintained on the second adhesive layer before UV irradiation, and the masking film can be properly bonded to the second adhesive layer even after UV irradiation. In addition to being able to remain on the second adhesive layer, the second adhesive layer can be easily re-peelable from the adherend:

[Equation 1]

Decrease rate of adhesion = ｜PS2 - PS1｜/ PS1 x 100

(In Equation 1 above,

PS1 is the adhesive strength of the second adhesive layer before UV irradiation,

PS2 is the adhesive strength of the second adhesive layer after UV irradiation)

The "adhesive force before UV irradiation" and "adhesive force after UV irradiation" may be measured with reference to the following experimental examples.

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 on a part of the second adhesive layer. Therefore, in order to reduce the step difference depending on whether or not the masking film is formed in the second adhesive layer, it may be preferable that the masking film is included in a depressed form in the second adhesive layer. Accordingly, the modulus of the first adhesive layer and the second adhesive layer should be different from each other. The “modulus” means the 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 the relationship of Equation 2:

[Equation 2]

G1 > G2

(In Equation 2 above,

G1 is the modulus of the first adhesive layer,

G2 is the modulus of the second adhesive layer).

By having the relationship of Equation 2, it is possible to facilitate lamination of the masking film on the lower surface of the second pressure-sensitive adhesive layer, and it is possible to use the pressure-sensitive adhesive sheet even in the vacuum compression process while maintaining the strength of the pressure-sensitive adhesive sheet.

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

For example, the modulus of the first adhesive layer may be 0.1 MPa or more, specifically 0.1 MPa to 0.15 MPa, more specifically 0.1 MPa to 0.12 MPa. Within the above range, the shape of the pressure-sensitive adhesive sheet may be maintained even by vacuum compression during bonding of 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 recessed and laminated in the second adhesive layer, and the step difference due to the formation of the masking film may be reduced.

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

The "adhesive force" refers to the peel strength when the first or second adhesive layer is irradiated with UV and peeled at a peel angle of 180° at a peeling rate of 300 mm/min at 25° C. with respect to an adherend, for example, an alkali-free glass plate. . Through this, the adhesive sheet may be selectively peeled off because the adhesive strength between the first adhesive layer and the second adhesive layer is different after UV curing.

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 the following formula 3:

[Equation 3]

PS2 > PS3

(In Equation 3 above,

PS2 is the adhesive strength of the second adhesive layer after UV irradiation,

PS3 is the adhesive strength of the first adhesive layer after UV irradiation).

By having the relationship of Equation 3 above, the pressure-sensitive adhesive sheet can be used as a double-sided pressure-sensitive adhesive sheet for temporarily fixing panels.

For example, the ratio (PS2/PS3) of the adhesive force after UV irradiation of the second adhesive layer to the adhesive force after UV irradiation of the first adhesive layer is 1.1 or more, specifically 2.4 or more, more specifically 2.4 to 6. . In the above range, the first adhesive layer and the second adhesive layer may be formed as UV-curable adhesive layers, respectively.

For example, the adhesive strength 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. Within the above range, since the adhesive force of the first adhesive layer to the adherend is low, fairness can be ensured.

For example, the adhesive strength 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 is first separated, and then the selective peeling effect of peeling the tape from the glass through air blowing can be obtained.

Each thickness of the first adhesive layer and the second adhesive layer may be appropriately adjusted according to the purpose 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 possible to easily manufacture the pressure-sensitive adhesive sheet, and to secure the peeling force to the adherend.

The first adhesive layer and the second adhesive layer are not particularly limited, but may be an active energy ray-curable adhesive layer. 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 irradiating light with an intensity of 300m J/cm ² to 3,000m J/cm ² under the condition of a wavelength of 200 nm to 450 nm for the first adhesive layer and the second adhesive layer.

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 a part of the second adhesive layer. Therefore, in order to solve the step difference depending on whether the masking film is formed in the second adhesive layer, the viscosity of the composition for forming the first adhesive layer and the second adhesive layer should be adjusted. The viscosity means a 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 pressure-sensitive adhesive layer and the composition for the first pressure-sensitive adhesive layer may have a relationship of Equation 4:

[Equation 4]

V1 > V2

(in Equation 4 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 Equation 4, lamination of the masking film on the lower surface of the second adhesive layer can be facilitated, and re-peelability by the air blowing process can be improved while maintaining the strength of the adhesive sheet.

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 may be 2 or more, specifically 2-3. In the above range, the first adhesive layer and the second adhesive layer may be formed as UV-curable adhesive layers, respectively.

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

The composition for the adhesive layer is a UV-curable (meth)acrylic adhesive layer composition, and is cured at a continuous wavelength emitted from a metal halide lamp or a high-pressure mercury lamp with an emission wavelength of 200 nm to 450 nm, or a specific wavelength from a wavelength of 200 nm to 450 nm emitted from a UV LED. A pressure-sensitive adhesive layer can be formed.

The composition for the adhesive layer includes a UV-curable adhesive binder resin, a curing agent, and a photoinitiator. The composition for the 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 easiness in supply and demand, UV curability, and the like. In one embodiment, as the (meth)acrylic resin, a resin obtained by adding 10% to 50% by weight of a (meth)acrylate functional group to a side chain may be used.

As the curing agent, a conventional curing agent such as an isocyanate-based curing agent and an epoxy-based curing agent may be used, and may be appropriately selected and used according to the type of the UV-curable adhesive binder resin. As the photoinitiator, a conventional type such as a phosphorus-based photoinitiator may be used. The filler is included in the composition for the pressure-sensitive adhesive layer to increase the modulus of the pressure-sensitive 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 it can be used as a type having a lower molecular weight than the UV-curable adhesive binder resin.

In one embodiment, the composition for the first adhesive layer is based on 100 parts by weight of the UV curable adhesive binder resin, 1 to 10 parts by weight of the curing agent, 0.1 to 5 parts by weight of the photoinitiator, 10 to 30 parts by weight of the filler. can In the above range, the modulus of the first adhesive layer, 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, 20 parts by weight to 30 parts by weight of a UV reactive oligomer may include In the above range, the modulus of the second adhesive layer, 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 the pressure-sensitive adhesive layer may not include a foaming agent or foaming agent having foaming properties due to 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 pressure-sensitive adhesive sheet, it provides a starting point for air to penetrate and at the same time secures the adhesion between the adherend and the second adhesive layer after UV irradiation, thereby achieving both re-peelability and adhesiveness at the same time. be able to achieve

In particular, in the pressure-sensitive adhesive sheet of the present invention, since the masking film is present as a separate layer separate from the second pressure-sensitive adhesive layer, the re-peelability is obtained without affecting the adhesive force of the second pressure-sensitive adhesive layer to the adherend.

In the pressure-sensitive adhesive sheet of FIG. 1 , a masking film is applied to form a non-adhesive surface on a portion of the second pressure-sensitive adhesive layer. However, the present invention is not limited thereto, and if a non-adhesive surface can be formed on the second pressure-sensitive adhesive layer, known means that are not limited to the masking film may be applied. However, the masking film is advantageous for lifting by air blowing as a film material, as detailed below, to provide a non-tacky surface and may be desirable for re-peelability.

The masking film 130 is formed on the second adhesive layer 120 to cover a portion 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 depressed state in the second adhesive layer. In another embodiment, the masking film may be formed on the lower surface of the second adhesive layer in a state that is not recessed 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) is 0.01 to 0.5, specifically 0.06 to 0.4, more specifically 0.14 to 0.31. In the above range, it is possible to achieve both re-peelability during the air blowing process and the adhesion of the second adhesive layer to the adherend.

The "area of the lower surface of the second adhesive layer" means the 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 on which the masking film is formed.

The masking film 130 is formed on the outer surface of the adherend surface of the second adhesive layer so as to be sufficient to provide a starting point through which air can penetrate. When the masking film is formed on the inside of the adherend surface 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, the masking film may be formed to include a corner portion when the second adhesive layer has a shape having a corner portion including an angled portion. Through this, it is possible to provide a starting point through which air can penetrate when air blowing is input 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 re-peelable adhesive sheet of FIG. 1 .

Referring to FIG. 2 , when the pressure-sensitive adhesive sheet has a rectangular shape, the pressure-sensitive 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. is formed only in The masking film 130 is not formed on a portion 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 may include N (N is an integer of 4 to 10) polygons such as a square, a rectangle, and a pentagon in addition to a triangular shape.

Referring to FIG. 2, when the second adhesive layer has a rectangular shape, the length c of the area without the masking film among one side of the rectangle and the length d of the area without the masking film among the other side adjacent to the side of the rectangle 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, adhesion to the adherend may be maintained, and air movement may be facilitated during the air blowing process.

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

The masking film 130 is not particularly limited in material as long as the lower surface of the masking film is non-adhesive so as to provide a non-adhesive surface to a portion of the second adhesive layer. For example, the masking film 130 may include an optically transparent resin film, specifically, a polyester-based resin film such as polyethylene terephthalate or 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 can be applied as a masking film, and can prevent defects due to step formation compared to the second adhesive layer.

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

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 the lower surface of the second adhesive layer in the adhesive sheet according to another embodiment of the present invention.

Referring to FIG. 3 , a masking film 130 is formed on the lower surface of the second adhesive layer 120A of the adhesive sheet. The masking film 130 is formed on a corner part 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. The masking film 130 is substantially the same as the pressure-sensitive adhesive sheet of FIG. 1 except that the corner portion is formed in a curved surface.

In contrast to the case where the masking film has an angled corner shape as shown in FIG. 2 , when the edge of the masking film has a curved surface as shown in FIG. 3 , air penetration by the air blowing process can be made easier.

Referring to FIG. 4, a re-peelable pressure-sensitive adhesive sheet according to another embodiment of the present invention will be described. 4 is a cross-sectional view of a re-peelable 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 pressure-sensitive adhesive sheet of FIG. 1 , except that the third pressure-sensitive adhesive layer 140 is additionally formed between the second pressure-sensitive 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. Within 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. The "NON-UV 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, unlike the above-described UV adhesive layer. In the present invention, the second adhesive layer 120 is a UV-curable adhesive layer, whereas the third adhesive layer 140 is cured by a method other than UV irradiation, thereby preventing the adhesive strength of the adhesive layer by UV irradiation from lowering. can get

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 curing agent described above. For example, 0.1 parts by weight to 10 parts by weight of a curing agent may be included with respect to 100 parts by weight of the adhesive binder resin that is not cured by UV.

Hereinafter, the manufacturing method of the re-peelable adhesive sheet of this invention is demonstrated.

The re-peelable adhesive sheet of the present invention is coated with a composition for the first adhesive layer on the upper surface of the base layer, the composition for the second adhesive layer is coated on the lower surface of the base layer, and a masking film is laminated on the coating layer, , it can be prepared by drying and then punching to a predetermined size.

In addition, the re-peelable adhesive sheet of the present invention is coated with the composition for the first adhesive layer on the upper surface of the base layer, the composition for the second adhesive layer is coated on the lower surface of the base layer, dried, and then a predetermined size It can be manufactured by punching with and laminating a masking film on the corresponding coating layer.

In addition, each step in the method for 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, the method of using the re-peelable adhesive sheet of this invention is demonstrated.

The re-peelable adhesive sheet of the present invention may 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, in the method of using the re-peelable adhesive sheet of the present invention, the re-peelable adhesive sheet of the present invention is placed on one surface of a carrier glass, and a light emitting device panel is placed on the re-peelable adhesive sheet. At this time, the first adhesive layer is directed toward the light emitting device panel, the first and second adhesive layers of the releasable adhesive sheet are cured with active energy rays, and the light emitting device panel is removed from the releasable adhesive sheet and separating the re-peelable adhesive sheet from the carrier glass.

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

Separating the re-peelable 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

It contains 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 relative to 100 parts by weight of UV-curable adhesive binder resin. A UV-curable adhesive composition was prepared. As the photocurable adhesive binder resin, a composition for a first adhesive layer was prepared using 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 the acrylic base resin.

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) as a UV-reactive oligomer was further added to prepare a composition for a first adhesive layer.

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

Containing 0.8 parts by weight of AK-DA (Aekyung Chemical), 25 parts by weight of UV-reactive oligomer M150 (Miwon Specialty Chemicals), and 1.6 parts by weight of IRGACURE 819 (Ciba) as a photoinitiator relative to 100 parts by weight of UV curable adhesive binder resin A UV-curable adhesive composition was prepared. As the photocurable adhesive binder resin, a composition for a second adhesive layer was prepared using 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 the acrylic base resin.

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 Corporation) were further added to prepare a second adhesive layer composition.

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

It contains 0.8 parts by weight of AK-DA (Aekyung Chemical), 12 parts by weight of UV-reactive oligomer M150 (Miwon Specialty Chemicals) and 1 part by weight of IRGACURE 127 (Ciba) as a photoinitiator relative to 100 parts by weight of UV-curable adhesive binder resin. A UV-curable adhesive composition was prepared. As the photocurable adhesive binder resin, a composition for a second adhesive layer was prepared using 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 the acrylic base resin.

Preparation Example 6: Preparation of the composition for the second adhesive layer

It contains 0.8 parts by weight of AK-DA (Aekyung Chemical), 16 parts by weight of UV-reactive oligomer M150 (Miwon Specialty Chemicals) and 1 part by weight of IRGACURE 127 (Ciba) as a photoinitiator relative to 100 parts by weight of UV-curable adhesive binder resin. A UV-curable adhesive composition was prepared. As the photocurable adhesive binder resin, a composition for a second adhesive layer was prepared using 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 the acrylic base resin.

Preparation Example 7: Preparation of the composition for the third adhesive layer

A Non-UV-curable adhesive composition containing 0.8 parts by weight of an isocyanate-based curing agent AK-DA (Aekyung Chemical Co.) relative to 100 parts by weight of the Non-UV adhesive binder resin was prepared. As the adhesive binder resin, a composition for a third adhesive layer was prepared using 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 the acrylic base resin.

[Evaluation of physical properties of the compositions of Preparation Examples 1 to 6]

For the composition of Preparation Example 1, the viscosity at 25° C. was measured by the Rheometer method (ASTM D4440).

The composition of Preparation Example 1 was applied to a polyethylene terephthalate (PET) film (thickness: 50 μm, SH34, SKC) to a thickness of 20 μm and dried at 120° C. for 3 minutes to form a first adhesive layer having a thickness of 20 μm. was prepared.

For the compositions of Preparation Examples 2 to 6, the viscosity was measured in the same manner as in Preparation Example 1, and a laminate having an adhesive layer having a thickness of 20 μm was formed in the same manner as in Preparation Example 1.

The storage modulus and adhesive force of Table 1 below were evaluated using the prepared laminate.

(1) Storage modulus: A specimen for measuring the storage modulus was prepared by stacking a plurality of samples obtained by cutting the adhesive layer into a circular specimen having a diameter of 8 mm x a thickness of 20 μm among the manufactured laminates and stacked in 50 layers. 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. Among them, the value at 25°C was taken.

(2) Adhesion: The prepared laminate was cut to 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 the adhesive force. Peeling strength (PS1) when the tape was peeled from an alkali-free glass plate at a peeling angle of 180°, a peeling temperature of 25°C, and a peeling rate of 300 mm/min was measured using an adhesive force measuring device (CHEMI LAB, SurTA).

In addition, after preparing the adhesive force specimen by the above method, UV was irradiated to the specimen with a metal halide lamp at an intensity of 300 m J/cm ² . Peeling strength (PS2) when the tape was peeled from an alkali-free glass plate at a peeling angle of 180°, a peeling temperature of 25°C, and a peeling rate of 300 mm/min was measured using an adhesive force measuring device (CHEMI LAB, SurTA).

The value of Equation 1 (|PS2 - PS1|/ PS1 x 100) was calculated using PS1 and PS2.

first adhesive layer 2nd adhesive layer Preparation Example 1 Preparation 2 Preparation 3 Preparation 4 Production Example 5 Preparation 6 Viscosity (cPs) 26,046 21,270 8,682 10,635 8,211 8,019 Storage modulus (MPa) 0.12 0.1 0.04 0.05 0.04 0.03 Adhesion before UV irradiation (gf/in) - - 160 440 408 384 Adhesion after UV irradiation (gf/in) 10 4 24 11 81 62 value of expression 1 - - 85.0 97.5 80.1 83.9

Example 1

As a base layer, the composition for the first adhesive layer of Preparation Example 1 is 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 was formed. On the lower surface of the PET film, the composition for the second adhesive layer of Preparation Example 3 was applied 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 / base layer / second adhesive layer was punched out in a square shape with a length of 30 mm x width of 30 mm as shown in FIG. 2 . As a masking film, a polyethylene terephthalate film (thickness: 38㎛, SM-38D, UNITIKA company) was cut into the shape shown in FIG. 2, and then the adhesive sheet was bonded to the lower surface of the coating film for the second adhesive layer as shown in FIG. prepared.

Examples 2 to 6

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

Example 7

An adhesive sheet was prepared in the same manner as in Example 1, except that the size and/or shape of the masking film and/or the composition of the adhesive layer in Example 1 were changed as shown in Table 3 below.

Example 8

As a base layer, the composition for the first adhesive layer of Preparation Example 2 is 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 was formed. On the lower surface of the PET film, the composition for the second adhesive layer of Preparation Example 4 was applied to a predetermined thickness, and a coating film for the second adhesive layer was formed. As shown in FIG. 4 on a portion of the lower surface of the coating film for the second adhesive layer, the composition for the third adhesive layer of Preparation Example 7 was applied 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 out in a square shape of 30 mm in length x 30 mm in width as shown in FIG. 2 . As a masking film, a polyethylene terephthalate film (thickness: 38㎛, SM-38D, UNITIKA company) was cut into the shape shown in FIG. 2, and then the adhesive sheet was bonded to the lower surface of the coating film for the second adhesive layer as shown in FIG. prepared.

Comparative Example 1

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that in Example 1, the composition of the pressure-sensitive adhesive layer was changed as shown in Table 3 below without forming a masking film on the lower surface of the second pressure-sensitive adhesive layer.

Comparative Example 2

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 2, except that in Example 2, the second pressure-sensitive adhesive layer was formed from the composition for the pressure-sensitive adhesive layer of Preparation Example 5.

Comparative Example 3

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 2, except that in Example 2, the second pressure-sensitive adhesive layer was formed from the composition for the pressure-sensitive adhesive layer of Preparation Example 6.

The following physical properties were evaluated for the pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples, and the results are shown in Tables 2 and 3 below.

Properties

Re-peelability: The prepared laminate was cut to length x width (100 mm x 1 inch), and the second adhesive layer surface was placed on an alkali-free glass plate with a 2 kg roller to prepare a reciprocating test piece. After irradiating the prepared specimen with UV at an intensity of 300 m J/cm ² with a metal halide lamp, air was sprayed for 2 seconds at a pressure of 0.4 MPa and an angle of 45 ° with an air gun to measure whether the laminate was peeled off from the alkali-free glass plate. When the said laminated body peels from an alkali-free-glass plate, when favorable and not peeling, it evaluated as impossibility.

Example One 2 3 4 5 6 masking film shape triangle triangle triangle triangle triangle triangle first adhesive layer Preparation Example 1 Preparation Example 1 Preparation Example 1 Preparation Example 1 Preparation Example 2 Preparation Example 2 2nd adhesive layer Preparation 3 Preparation 3 Preparation 3 Preparation 3 Preparation 4 Preparation 4 3rd adhesive layer - - - - - - Figure 2 a 5mm 5mm 11mm 8mm 5mm 5mm Figure 2b 14.5mm 12.5mm 12.5mm 12.5mm 14.5mm 12.5mm Figure 2 c 1mm 5mm 5mm 5mm 1mm 5mm Fig. 2d 20mm 20mm 8mm 14mm 20mm 20mm area ratio 0.16 0.14 0.31 0.22 0.16 0.14 re-peelability Good Good Good Good Good Good

Example comparative example 7 8 One 2 3 masking film shape triangle triangle - triangle triangle first adhesive layer Preparation Example 2 Preparation Example 2 Preparation Example 2 Preparation Example 1 Preparation Example 1 2nd adhesive layer Preparation 4 Preparation 4 Preparation 4 Production Example 5 Preparation 6 3rd adhesive layer - Preparation 7 - - - Figure 2 a 11mm 8mm - 5mm 5mm Figure 2b 12.5mm 12.5mm - 12.5mm 12.5mm Figure 2 c 5mm 5mm - 5mm 5mm Fig. 2d 8mm 14mm - 20mm 20mm area ratio 0.31 0.22 - 0.14 0.14 re-peelability Good Good impossible impossible impossible

As shown in Table 2 and Table 3, in the re-peelable pressure-sensitive adhesive sheet of the present invention, the re-peelable pressure-sensitive adhesive sheet was easily re-peeled from the carrier glass by the air blowing process during re-peelability evaluation.

On the other hand, as shown in Table 3, Comparative Example 1 not provided with a masking film did not have good re-peelability. Comparative Examples 2 and 3, which are out of the value of Equation 1 of the present invention, have strong peeling force after UV curing of the second adhesive layer, and thus the force attached to the glass is stronger than the air blowing strength, so that it can be easily removed from the glass in the air blowing process. There was a problem of not peeling off.

Simple modifications or changes of the present invention can be easily carried out 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 (14)

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, and a masking film is formed on some of the lower surfaces of the second adhesive layer, ,
The second adhesive layer has a storage modulus of 0.04 MPa to 0.06 MPa at 25° C.,
In the second adhesive layer, the value of the following formula 1 between the adhesive force before UV irradiation and the adhesive force after UV irradiation is 84% to 99%, the re-peelable adhesive sheet:
[Equation 1]
Decrease rate of adhesion = ｜PS2 - PS1｜/ PS1 x 100
(In Equation 1 above,
PS1 is the adhesive strength of the second adhesive layer before UV irradiation,
PS2 is the adhesive strength of the second adhesive layer after UV irradiation).
The re-peelable pressure-sensitive adhesive sheet of claim 1, wherein the masking film is formed in a depressed state in the lower surface of the second adhesive layer.
According to claim 1, 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, S3 is the total area of the masking film area) is 0.01 to 0.5, the re-peelable adhesive sheet.
The re-peelable pressure-sensitive adhesive sheet according to claim 3, wherein the area ratio S3/S2 is 0.14 to 0.31.
According to claim 1, wherein the masking film is formed in the corner of the outer surface of the lower surface of the second adhesive layer, the releasable pressure-sensitive adhesive sheet.
The re-peelable pressure-sensitive adhesive sheet according to claim 5, wherein the masking film has an angled edge.
The re-peelable adhesive sheet of claim 1, wherein the masking film has a light transmittance of 50% or more for UV.
The re-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the base layer comprises a colored film.
The re-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the base layer has a haze of 20% or less.
The re-peelable pressure-sensitive adhesive sheet according to claim 1, wherein the first adhesive layer and the second adhesive layer have different storage modulus at 25°C.
The re-peelable pressure-sensitive adhesive sheet of claim 1, wherein the first adhesive layer and the second adhesive layer have different adhesive strengths after UV irradiation.
According to claim 1, wherein the first adhesive layer and the second adhesive layer will each include a UV-curable (meth)acrylic adhesive layer, the releasable adhesive sheet.
The re-peelable adhesive sheet of claim 1, wherein a third adhesive layer is further formed between the second adhesive layer and the masking film.
The re-peelable pressure-sensitive adhesive sheet according to claim 13, wherein the third pressure-sensitive adhesive layer comprises a NON UV-curable (meth)acrylic pressure-sensitive adhesive layer.

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