KR102482482B1 - Adhesive film, manufacturing method of same and plastic organic light emitting display comprising same - Google Patents

Abstract

The present application relates to an adhesive film, a manufacturing method thereof, and a plastic organic light emitting display including the same.

Description

Adhesive film, manufacturing method thereof, and plastic organic light emitting display including the same

The present application relates to an adhesive film, a manufacturing method thereof, and a plastic organic light emitting display including the same.

With the recent development of display-related technologies, display devices that can be deformed during use, such as folding, rolling in a roll shape, or stretching like a rubber band, have been researched and developed. Since these displays can be deformed into various shapes, they can satisfy both the demand for a larger display in the use stage and the demand for a smaller display for portability.

The deformable display device may not only be deformed into a preset shape, but also may be deformed into various shapes according to a user's request or a situation in which the display device is used. Therefore, it is necessary to recognize the deformed shape of the display and control the display device in response to the recognized shape.

Meanwhile, since the deformable display device has a problem in that each component of the display device is damaged due to deformation, each component of the display device must satisfy folding reliability and stability.

In particular, recently, demand for a foldable display is increasing, and demand for a plastic organic light emitting display, which is a type of deformable foldable display, is also increasing. Since the foldable display involves folding and unfolding operations, it is essential to attach a supporter that serves as a guideline for the operation to the bottom of the substrate of the foldable display. In the case of a backplate for a conventional display, an adhesive is coated on the end surface of a base material, so a process of forming an additional adhesive or adhesive is required to attach a support that serves as a guideline to the lower portion.

In particular, for the implementation of a foldable display, the viscoelastic behavior of the adhesive film is particularly important, and the adhesive film has good creep characteristics when folding the display, so the stress generated during folding should be relieved. and should have good recovery characteristics after creep deformation to suppress cracks that occur during folding.

In addition, air bubbles or unexpected foreign substances generated in the process of bonding the adhesive sheet to the substrate may flow in, which is undesirable from the viewpoint of aesthetics or adhesiveness, and re-adhesion of the adhesive sheet may be required. However, in the case of an adhesive sheet having high adhesive strength, such re-adhesion work is difficult.

Then, a technique for reducing such bubbles has been devised. For example, a technique of forming a concavo-convex surface shape on the adhesive surface of a pressure-sensitive adhesive using an embossed liner has been devised. In this case, when the pressure-sensitive adhesive is bonded to the substrate, even if air bubbles are mixed between the two, air easily flows out through the grooves on the surface of the pressure-sensitive adhesive, so that air bubbles can be easily removed without re-adhesion. However, the pressure-sensitive adhesive described above requires a certain thickness in order to form grooves. In addition, when this pressure-sensitive adhesive is lightly adhered to a base material, the adhesion area is reduced due to the presence of grooves, making it easy to perform operations such as rework and repositioning, but sufficient adhesive strength cannot be obtained. There is a possibility.

In order to enhance the rework characteristics, recently, an adhesive sheet having low adhesive strength in the initial stage of the adhesive sheet and increasing the adhesive strength after a specific process has been developed.

Therefore, in view of this situation, the adhesive force is maintained low in the initial stage of adhesion, and at the same time, the ability to develop sufficient adhesive force necessary for fixing the substrate to be adhered thereafter, and for the implementation of a foldable display, the creep of the adhesive film ) characteristics, it is necessary to study an adhesive film that relieves stress generated during folding and has good recovery characteristics after creep deformation.

Japanese Patent Laid-Open No. 2006-299283

The present application is intended to provide an adhesive film, a manufacturing method thereof, and a plastic organic light emitting display including the same.

An exemplary embodiment of the present application is a base film; And an adhesive film comprising an adhesive sheet provided on one side of the base film,

After bonding the opposite side of the surface in contact with the base film of the adhesive sheet to stainless steel (SUS304 substrate), the initial adhesive strength after leaving it at 23°C for 3 hours is 200 gf/inch or less, and then heat-treated at 50°C for 20 minutes. Adhesion is over 800gf/inch,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at -20 ° C temperature is X1,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 25 ° C is X2,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 60 ° C is X3,

The X1 to X3 provide an adhesive film that satisfies Equations 2 and 3 below.

[Equation 1]

[(F1-F2) / F1] X 100

[Equation 2]

X1/X2 > 0.9

[Equation 3]

X3/X2 > 1.0

In the above formula 1,

F1 means the strain generated by applying a shear force to the adhesive sheet for 10 minutes,

F2 means the strain after applying a shear force to the pressure-sensitive adhesive sheet for 10 minutes and recovering for 10 minutes at a shear force of 0 μNm.

Another exemplary embodiment of the present application includes preparing a base film; and forming a pressure-sensitive adhesive sheet by applying and curing a pressure-sensitive adhesive composition on one surface of the base film,

After bonding the opposite side of the surface in contact with the base film of the adhesive sheet to stainless steel (SUS304 substrate), the initial adhesive strength after leaving it at 23°C for 3 hours is 200 gf/inch or less, and then heat-treated at 50°C for 20 minutes. Adhesion is over 800gf/inch,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at -20 ° C temperature is X1,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 25 ° C is X2,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 60 ° C is X3,

The X1 to X3 provide a method for producing an adhesive film that satisfies the following formulas 2 and 3.

[Equation 1]

[(F1-F2) / F1] X 100

[Equation 2]

X1/X2 > 0.9

[Equation 3]

X3/X2 > 1.0

In the above formula 1,

F1 means the strain generated by applying a shear force to the adhesive sheet for 10 minutes,

F2 means the strain after applying a shear force to the pressure-sensitive adhesive sheet for 10 minutes and recovering for 10 minutes at a shear force of 0 μNm.

Another exemplary embodiment of the present application is an adhesive film according to the present application; and a plastic organic light emitting display provided on the adhesive sheet side of the adhesive film.

Finally, an exemplary embodiment of the present application includes a liquid crystal display provided on a surface opposite to a surface of the plastic substrate in contact with the adhesive film; and an organic light emitting layer on a surface opposite to a surface of the liquid crystal display in contact with the plastic substrate.

The adhesive film according to an exemplary embodiment of the present application includes a polymer having a melting temperature (Tm) of 30° C. or more and a (meth)acrylate-based resin in the adhesive sheet, and the adhesive sheet including the same has initial adhesive strength with the substrate to be adhered. have these low characteristics.

In particular, in the case of the adhesive sheet included in the adhesive film according to one embodiment of the present application, the initial adhesive strength with the adherend substrate is low, and at the same time, the adhesive strength increases after a specific process to develop sufficient adhesive strength to fix the adherend substrate. have

That is, in the adhesive film according to the present application, the adhesive strength of the adhesive sheet to the adherend substrate is initially maintained low, and no dirt remains even when it is removed in case of erroneous attachment, and then the adhesive strength is increased through a specific process to increase the adhesive strength characterized by being maintained.

In addition, the creep recovery rate of the adhesive film according to an exemplary embodiment of the present application satisfies Equations 2 and 3 above so that it can be applied to foldable displays, and thus has excellent stress relieving properties generated during folding of the foldable display. and has a feature capable of suppressing the occurrence of cracks.

That is, the adhesive film according to an exemplary embodiment of the present application has excellent creep recovery rate at low temperature, room temperature, and high temperature, and a plastic organic light emitting display including the same has excellent folding characteristics. .

1 is a diagram showing a schematic laminated structure of an adhesive film according to an exemplary embodiment of the present application.
2 is a diagram showing a laminated structure of an adhesive film including a release film according to an exemplary embodiment of the present application.
3 is a diagram showing a DSC graph of a polymer showing glass transition temperature behavior.
4 is a diagram showing a DSC graph of a polymer showing melting temperature behavior.

Hereinafter, this specification will be described in more detail.

In the present specification, when a part "includes" a certain component, it means that it may further include other components, not excluding other components unless otherwise stated.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

An exemplary embodiment of the present application is a base film; And an adhesive film comprising an adhesive sheet provided on one side of the base film,

After bonding the opposite side of the surface in contact with the base film of the adhesive sheet to stainless steel (SUS304 substrate), the initial adhesive strength after leaving it at 23°C for 3 hours is 200 gf/inch or less, and then heat-treated at 50°C for 20 minutes. Adhesion is over 800gf/inch,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at -20 ° C temperature is X1,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 25 ° C is X2,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 60 ° C is X3,

The X1 to X3 provide an adhesive film that satisfies Equations 2 and 3 below.

[Equation 1]

[(F1-F2) / F1] X 100

[Equation 2]

X1/X2 > 0.9

[Equation 3]

X3/X2 > 1.0

In the above formula 1,

F1 means the strain generated by applying a shear force to the adhesive sheet for 10 minutes,

F2 means the strain after applying a shear force to the pressure-sensitive adhesive sheet for 10 minutes and recovering for 10 minutes at a shear force of 0 μNm.

In the case of the adhesive film according to the present application, the initial adhesive strength of the adhesive sheet has a range of 200 gf / inch or less, and the late adhesive strength after heat treatment has a value of 800 gf / inch or more, and the adhesive strength to the adherend substrate is initially maintained low, It is characterized in that no dirt is left even if it is removed in case of erroneous attachment, and then the adhesive force is increased through a specific process to maintain the adhesive force with the adherend substrate.

In addition, the creep recovery rate of the adhesive film according to an exemplary embodiment of the present application satisfies Equations 2 and 3 above so that it can be applied to foldable displays, and thus has excellent stress relieving properties generated during folding of the foldable display. and has a feature capable of suppressing the occurrence of cracks, the adhesive film according to an exemplary embodiment of the present application has excellent creep recovery rate at low temperature, room temperature, and high temperature, and plastic organic light emitting including the same In the case of a display, folding characteristics are excellent.

The initial adhesive force and the late adhesive force were measured using a texture analyzer (Stable Micro Systems Co.) at an angle of 180° and a peeling speed of 300 mm/min, and the adhesive sheet according to the present invention was measured at a size of 1 inch. After cutting it into , it was reciprocated once with a 2kg rubber roller, attached to the SUS304 substrate, and then measured.

The SUS304 substrate means a stainless steel substrate.

That is, the initial adhesive strength is obtained by cutting the adhesive sheet according to the present invention to a size of 1 inch, reciprocating once with a 2kg rubber roller, attaching it to a SUS304 substrate, leaving it at 23 ° C for 3 hours, and then applying a 180° angle and 300 mm / It refers to the value measured using a texture analyzer (Stable Micro Systems Inc.) while peeling at a peeling speed of 10 min.

The late adhesive strength is measured by cutting the adhesive sheet according to the present invention to a size of 1 inch, reciprocating once with a 2kg rubber roller, attaching it to a SUS304 substrate, leaving it at 23 ° C for 3 hours, and then at 50 ° C for 20 minutes. It refers to the value measured using a texture analyzer (Stable Micro Systems Inc.) while peeling at an angle of 180° and a peeling speed of 300 mm/min after heat treatment.

In one embodiment of the present application, the initial adhesive strength after bonding the opposite side of the surface of the adhesive sheet in contact with the base film to the SUS304 substrate and leaving it at 23 ° C for 3 hours is 200 gf / inch or less, preferably 180 gf / inch inch or less, more preferably 150 gf/inch or less.

In another exemplary embodiment, the initial adhesive strength after bonding the opposite surface of the surface of the adhesive sheet in contact with the base film to the SUS304 substrate and leaving it at 23 ° C for 3 hours is 50 gf / inch or more, preferably 80 gf / inch or more , more preferably 90 gf/inch or more.

In another exemplary embodiment, after bonding the opposite surface of the surface of the adhesive sheet in contact with the base film to the SUS304 substrate, leaving it at 23 ° C for 3 hours and heat-treating at 50 ° C for 20 minutes, the adhesive strength at the end is 800 gf / inch or more , Preferably it may be 850 gf / inch or more, more preferably 880 gf / inch or more.

In another exemplary embodiment, after bonding the opposite surface of the surface of the adhesive sheet in contact with the base film to the SUS304 substrate, leaving it at 23 ° C for 3 hours and heat-treating at 50 ° C for 20 minutes, the adhesive strength at the end is 5000 gf / inch or less , preferably 4000 gf/inch or less, more preferably 3000 gf/inch or less.

In one embodiment of the present application, after bonding the opposite surface of the surface in contact with the base film of the pressure-sensitive adhesive sheet to the SUS304 substrate, the medium-term adhesive strength after leaving at 23 ° C. for 24 hours is 210 gf / inch or less, preferably 190 gf / inch inch or less, more preferably 170 gf/inch or less.

In another exemplary embodiment, after bonding the opposite surface of the surface in contact with the base film of the pressure-sensitive adhesive sheet to the SUS304 substrate, the medium-term adhesive strength after leaving at 23 ° C. for 24 hours is 55 gf / inch or more, preferably 85 gf / inch or more , More preferably, it may be 95 gf / in or more.

As described below, the adhesive film according to the present application includes a polymer having a melting temperature of 30 ° C or higher in the adhesive sheet, so that the adhesive strength remains constant at a low level even after leaving for 3 hours / 24 hours at room temperature (23 ° C). It has a characteristic that is maintained, so that no dirt remains even when it is removed in case of erroneous attachment, and then the adhesive force is increased through a specific process to maintain the adhesive force with the adherend substrate.

In addition, the adhesive film according to the present application includes the polymer having a melting temperature of 30 ° C or more as described above in the adhesive sheet, so that it has the above variable characteristics and the middle-term adhesive strength after being left at 23 ° C for 24 hours is within the above range It is characterized in that it satisfies, which is a characteristic in which the adhesive strength is maintained constant without increasing even when stored at room temperature for a long time, and has particularly excellent stability over time.

In one embodiment of the present application, an adhesive film having a value of 5 or more and 100 or less is provided for the late adhesive strength/initial adhesive strength.

In one embodiment of the present application, the value of the late adhesive strength/initial adhesive strength may be 5 or more and 100 or less, preferably 10 or more and 80 or less.

In one embodiment of the present application, an adhesive film having a value of 0.8 or more and 1.2 or less of the mid-term adhesive strength/initial adhesive strength is provided.

In an exemplary embodiment of the present application, the creep recovery rate (Creep recovery, %) represented by Equation 1 below at -20 ° C temperature is X1, and the creep recovery rate represented by Equation 1 below at 25 ° C temperature (Creep recovery, % ) is X2, and the creep recovery (%) represented by the following formula 1 at a temperature of 60 ° C is X3, and the X1 to X3 provide an adhesive film that satisfies the following formulas 2 and 3.

[Equation 1]

[(F1-F2) / F1] X 100

[Equation 2]

X1/X2 > 0.9

[Equation 3]

X3/X2 > 1.0

In the above formula 1,

F1 means the strain generated by applying a shear force to the adhesive sheet for 10 minutes,

F2 means the strain after applying a shear force to the pressure-sensitive adhesive sheet for 10 minutes and recovering for 10 minutes at a shear force of 0 μNm.

In one embodiment of the present application, the F1 can be measured using TA Instrument's DHR (Discovery Hybrid Rheometer) HR-2 equipment. Specifically, after manufacturing a specimen having a thickness of 1 mm by overlapping an adhesive film several times, , it can be measured as the strain generated by applying a shear force corresponding to a torque of 1005 μNm for 10 minutes using a parallel plate fixture with a diameter of 8 mm.

In one embodiment of the present application, the F2 can be measured using TA Instrument's DHR (Discovery Hybrid Rheometer) HR-2 equipment. Specifically, after manufacturing a specimen having a thickness of 1 mm by overlapping an adhesive film several times, , Strain after applying a shear force corresponding to a torque of 1005 μNm for 10 minutes using a parallel plate fixture with a diameter of 8 mm, and then recovering for 10 minutes by setting the shear force to 0 μNm at the strain in that state ( strain) can be measured.

In one embodiment of the present application, X1 satisfies Equation 4 below, X2 satisfies Equation 5 below, and X3 satisfies Equation 6 below.

[Equation 4]

80.0 < X1 < 90.0

[Equation 5]

80.0 < X2 < 90.0

[Equation 6]

85.0 < X3 < 95.0

In an exemplary embodiment of the present application, Equation 4 may satisfy 80.0 < X1 < 90.0, preferably 81.0 < X1 < 88.0, and more preferably 81.5 < X1 < 86.0.

In an exemplary embodiment of the present application, Equation 5 may satisfy 80.0 < X2 < 90.0, preferably 81.0 < X2 < 88.0, and more preferably 81.5 < X2 < 86.0.

In an exemplary embodiment of the present application, Equation 6 may satisfy 85.0 < X3 < 95.0, preferably 88.0 < X3 < 93.0, and more preferably 88.5 < X3 < 92.5.

The adhesive film according to an exemplary embodiment of the present application has an excellent creep recovery rate at low temperature (-20 ° C), room temperature (25 ° C), and high temperature (60 ° C), and as it satisfies the above range, the folder The folding characteristics of the black display are excellent, and it has a characteristic that cracks do not occur.

1 shows a side view of the adhesive film according to the present application, and specifically, it can be confirmed that the adhesive film 40 has a form in which the base film 10 / the adhesive sheet 20 are sequentially stacked.

In one embodiment of the present application, the pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive composition or a cured product thereof, and the pressure-sensitive adhesive composition includes a (meth)acrylate-based resin; And a polymer having a melting temperature (Tm) of 30 ° C or higher,

The polymer is a copolymer of a monofunctional polysiloxane and one or more monomers,

The (meth) acrylate-based resin is based on 100 parts by weight of the (meth) acrylate-based resin,

80 to 99 parts by weight of an alkyl acrylate monomer; and

It provides an adhesive film comprising 1 to 30 parts by weight of an acrylate monomer having a hydroxyl or carboxyl functional group.

The melting temperature according to the present application means the temperature at which a phase transition of a material from a solid state to a liquid state occurs. A change corresponding to can be observed, and the temperature at this time can be defined as the melting temperature.

The melting temperature can be measured by differential thermal analysis (DSC). Specifically, it is a value measured by drawing the endothermic and calorific value of a material according to temperature as a phase transition occurs when a sample of about 10 mg is sealed in a dedicated pen and heated in a certain elevated temperature environment.

That is, since the pressure-sensitive adhesive composition according to an exemplary embodiment of the present application includes a polymer exhibiting melting temperature (Tm) behavior, it has excellent variable properties compared to the case of including a polymer exhibiting glass transition temperature (Tg) behavior, and , especially at room temperature (25 ° C), it has excellent stability over time without an increase in adhesive strength.

3 below shows a DSC graph for a polymer showing glass transition temperature (Tg) behavior, and FIG. 4 below shows a DSC graph for a polymer showing melting temperature (Tm) behavior.

As can be seen in FIG. 3, in the case of a polymer exhibiting glass transition temperature behavior, it can be confirmed that a phase transition occurs as the temperature is gradually increased with respect to a stable period (Glassy), and a phase transition (Glassy-> Rubbery) can be confirmed. That is, in the case of including a polymer exhibiting glass transition temperature behavior, variable characteristics may occur, but the phase transition temperature range is wide, and when stored at room temperature (25 ℃) for a long time, some phase transition occurs, increasing the adhesive strength of the pressure-sensitive adhesive layer and stability over time This may lead to poor results, and the variable characteristics may not be excellent in the phase transition state to the rubbery state.

Conversely, as can be seen in FIG. 4, in the case of polymers showing melting temperature behavior, when the temperature is gradually increased with respect to the stable period (Solid), it can be seen that a rapid phase transition (Solid->liquid) occurs at a specific temperature (melting). there is. That is, in the case of including a polymer exhibiting melting temperature behavior, a rapid phase transition occurs at a specific temperature value, so that the phase transition does not occur at a temperature below the melting temperature, thereby suppressing the increase in adhesive strength (excellent stability over time), and higher than the melting temperature. At the above temperature, a phase transition occurs, resulting in a rapid increase in adhesive strength (excellent variable properties).

In one embodiment of the present application, the pressure-sensitive adhesive sheet may include the pressure-sensitive adhesive composition as it is.

In one embodiment of the present application, the pressure-sensitive adhesive sheet may include the dried pressure-sensitive adhesive composition.

In one embodiment of the present application, the pressure-sensitive adhesive sheet may include a cured product of the pressure-sensitive adhesive composition.

In one embodiment of the present application, the monomer provides an adhesive film represented by Formula 1 below.

[Formula 1]

In Formula 1,

X is N or O;

R ₁ is hydrogen or a methyl group;

n is an integer from 1 to 30;

In an exemplary embodiment of the present application, n in Formula 1 may be an integer from 1 to 30.

In another exemplary embodiment, n in Formula 1 may be an integer of 10 to 25.

In another exemplary embodiment, n in Formula 1 may be an integer of 16 to 22.

In one embodiment of the present application, the X may be N.

In one embodiment of the present application, when the X has N, hydrogen may be omitted and displayed, and specifically, X means NH.

In one embodiment of the present application, the X may be O.

In Formula 1, in particular, when the value of n has the above range, some crystallization begins to occur due to entanglement between side chains of carbon, so that the polymer including it can exhibit melting temperature (Tm) behavior do.

The polymer having a melting temperature of 30° C. or higher means that the final polymer has a melting temperature of 30° C. or higher when the monofunctional polysiloxane and one or more monomers represented by Formula 1 are copolymerized.

In one embodiment of the present application, the melting temperature of the polymer may be 30 ° C or higher, 70 ° C or lower, preferably 60 ° C or lower, more preferably 50 ° C or lower.

In one embodiment of the present application, the components of the polymer included in the pressure-sensitive adhesive composition can be identified through GC (Gas chromatography) analysis, and the composition can be identified through NMR (Nuclear magnetic resonance) analysis.

The copolymerization means a polymer obtained by polymerizing two or more different types of units, and in the copolymer, two or more types of units may be arranged irregularly or regularly.

The copolymer is a random copolymer in which monomers are mixed with each other without regularity, a block copolymer in which blocks arranged in a certain section are repeated, or an alternating copolymer in which monomers are alternately repeated and polymerized. There may be an alternating copolymer, and the polymer having a melting temperature of 30° C. or higher according to an exemplary embodiment of the present application may be a random copolymer, a block copolymer, or an alternating copolymer.

In one embodiment of the present application, the monomer represented by Chemical Formula 1 provides an adhesive film in which at least one selected from the group consisting of STA (Stearyl acrylate) and STMA (Stearyl methacrylate).

As the monofunctional polysiloxane according to the present application, Chisso's FM-0721, Shin-Etsu's KF2012, etc. may be used, but is not limited thereto.

In one embodiment of the present application, the polymer having a melting temperature of 30 ° C or higher may have a weight average molecular weight of 30,000 g / mol to 200,000 g / mol.

In another embodiment, the polymer having a melting temperature of 30 ° C or higher may have a weight average molecular weight of 30,000 g / mol to 150,000 g / mol, preferably 30,000 g / mol to 100,000 g / mol .

When the polymer having a melting temperature of 30° C. or higher according to the present application has a weight average molecular weight value within the above range, the arrangement of molecules in the polymer is excellent, resulting in a low initial adhesive strength when a pressure-sensitive adhesive sheet is subsequently manufactured.

The weight average molecular weight is one of the average molecular weights in which the molecular weight of a certain polymer material is used as a standard and the molecular weight is not uniform, and is a value obtained by averaging the molecular weights of component molecular species of a polymer compound having a molecular weight distribution by weight fraction.

The weight average molecular weight may be measured through Gel Permeation Chromatography (GPC) analysis.

In one embodiment of the present application, the polymer having a melting temperature of 30 ° C or higher is the monofunctional polysiloxane; said one or more monomers; And it can be prepared by including a thermal polymerization initiator in a polymer composition containing a solvent.

Although toluene may be used as the solvent, it is not limited thereto as long as it can dissolve the monofunctional polysiloxane and the at least one monomer, and a general organic solvent may be used accordingly.

In one embodiment of the present application, the polymer having a melting temperature of 30 ° C or higher is based on 100 parts by weight of the polymer having a melting temperature of 30 ° C or higher, 10 parts by weight or more and 40 parts by weight or less of the monofunctional polysiloxane, and 60 parts by weight of the monomer It provides an adhesive film comprising more than 90 parts by weight or less.

In an exemplary embodiment of the present application, the polymer having a melting temperature of 30 ° C or higher is 10 parts by weight or more and 40 parts by weight or less, preferably 15 parts by weight of the monofunctional polysiloxane based on 100 parts by weight of the polymer having a melting temperature of 30 ° C or higher. It may contain more than 30 parts by weight or less, more preferably 18 parts by weight or more and 25 parts by weight or less.

In an exemplary embodiment of the present application, the polymer having a melting temperature of 30 ° C or higher is 60 parts by weight or more and 90 parts by weight or less, preferably 65 parts by weight or more 85 parts by weight based on 100 parts by weight of the polymer having a melting temperature of 30 ° C or higher. It may include 85 parts by weight or less, more preferably 70 parts by weight or more and 85 parts by weight or less.

When the polymer having a melting temperature of 30 ° C or higher according to the present application includes the monofunctional polysiloxane and the monomer by weight, the melting temperature value of the entire polymer may be appropriately formed, and accordingly, at room temperature of the adhesive sheet later The initial adhesive strength can be maintained low, and stability over time at room temperature also has excellent characteristics.

In one embodiment of the present application, the pressure-sensitive adhesive composition provides an adhesive film containing 1 part by weight or more and 10 parts by weight or less of a polymer having a melting temperature of 30 ° C. or higher based on 100 parts by weight of a (meth)acrylate-based resin.

In another embodiment, the pressure-sensitive adhesive composition is based on 100 parts by weight of (meth)acrylate-based resin, 1 part by weight or more and 7 parts by weight or less, preferably 3 parts by weight or more 7 parts by weight of a polymer having a melting temperature of 30 ° C or higher. may be included below.

When the polymer having a melting temperature of 30 ° C. or higher is included in the pressure-sensitive adhesive composition in a weight part within the above range, the amount of the polymer present is suitable and the stability over time at room temperature is excellent, so that the adhesive strength can be maintained constant, When applied to a plastic organic light emitting display in the future, in a variable process, it has excellent variable performance.

In one embodiment of the present application, the (meth)acrylate-based resin may include a (meth)acrylate-based resin having a weight average molecular weight of 100,000 g/mol to 5 million g/mol.

In this specification, (meth)acrylate is meant to include both acrylate and methacrylate. The (meth)acrylate-based resin may be, for example, a copolymer of a (meth)acrylic acid ester-based monomer and a crosslinkable functional group-containing monomer.

The copolymer refers to a polymer obtained by polymerizing two or more different types of units, and in the copolymer, two or more types of units may be arranged irregularly or regularly.

The copolymer is a random copolymer in which monomers are mixed with each other without regularity, a block copolymer in which blocks arranged in a certain section are repeated, or an alternating copolymer in which monomers are alternately repeated and polymerized. There may be alternating copolymers.

In one embodiment of the present application, the (meth) acrylate-based resin provides an adhesive film having a glass transition temperature of 0 ° C or less.

The glass transition temperature of the (meth)acrylate-based resin means the glass transition temperature of the entire final (meth)acrylate-based resin in which the monomers are polymerized, and in the present specification, the glass transition temperature is a differential scanning calorimeter (DSC, Mettler Co.), a value measured by drawing the endothermic and calorific value of the material according to the temperature as the phase transition occurs when about 10 mg of the sample is sealed in a dedicated pen and heated in a certain elevated temperature environment.

Specifically, the glass transition temperature is a nominal value described in literature, catalogs, etc., or a value calculated based on the following general formula (1) (Fox formula).

[general formula (1)]

1/Tg=W1/Tg1+W2/Tg2+... +Wn/Tgn

In the above general formula (1), Tg is the glass transition temperature of polymer A (unit: K), Tgi (i = 1, 2, ... n) is the glass transition temperature when monomer i forms a homopolymer (unit: : K), Wi (i = 1, 2, ... n) represents the mass fraction of monomer i in all monomer components.

In the above general formula (1), polymer A is monomer 1, monomer 2, . . . , means a calculation formula in the case of including n types of monomer components of monomer n.

In one embodiment of the present application, the glass transition temperature (Tg, glass transition temperature) of the (meth) acrylate-based resin is -100 ℃ or more and 0 ℃ or less to provide an adhesive film.

In another embodiment, the glass transition temperature (Tg, glass transition temperature) of the (meth)acrylate-based resin is -100 ° C or more and 0 ° C or less, preferably -80 ° C or more -30 ° C or less, more preferably Preferably, it may be -70 ° C or more and -50 ° C or less.

As the glass transition temperature of the (meth)acrylate-based resin included in the pressure-sensitive adhesive composition according to the present application satisfies the above range, the pressure-sensitive adhesive film according to the present application satisfies the ranges of Equations 2 and 3 to be used in foldable displays later. When applied, it has a characteristic capable of producing an excellent folding effect.

The (meth)acrylic acid ester-based monomer is not particularly limited, but examples thereof include alkyl (meth)acrylate, and more specifically, as a monomer having an alkyl group having 1 to 12 carbon atoms, pentyl (meth)acrylate, n-butyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethyl One or more of hexyl (meth)acrylate, dodecyl (meth)acrylate, and decyl (meth)acrylate may be included.

The crosslinkable functional group-containing monomer is not particularly limited, but may include, for example, one or more of a hydroxy group-containing monomer, a carboxyl group-containing monomer, and a nitrogen-containing monomer.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate. rate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, or 2-hydroxypropylene glycol (meth)acrylate.

Examples of the carboxyl group-containing monomer include (meth)acrylic acid, 2-(meth)acryloyloxyacetic acid, 3-(meth)acryloyloxypropyl acid, 4-(meth)acryloyloxybutyric acid, acrylic acid double sieve, itaconic acid, maleic acid, or maleic anhydride; and the like.

Examples of the nitrogen-containing monomer include (meth)acrylonitrile, N-vinyl pyrrolidone, or N-vinyl caprolactam.

In view of improving other functionalities such as compatibility, at least one of vinyl acetate, styrene, and acrylonitrile may be additionally copolymerized with the (meth)acrylate-based resin.

In one embodiment of the present application, the (meth) acrylate-based resin is based on 100 parts by weight of the (meth) acrylate-based resin, 80 to 99 parts by weight of an alkyl (meth) acrylate monomer; and 1 to 30 parts by weight of a (meth)acrylate monomer having a hydroxyl or carboxyl functional group.

The alkyl acrylate and alkyl methacrylate are monomers having an alkyl group having 1 to 12 carbon atoms, pentyl (meth) acrylate, n-butyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate rate, hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate and decyl (meth)acrylate One or more of them may be included.

In one embodiment of the present application, the alkyl (meth) acrylate monomer may be ethylhexyl acrylate (EHA).

In one embodiment of the present application, the (meth)acrylate monomer having a hydroxy functional group may be hydroxybutyl acrylate (HBA), and the (meth)acrylate monomer having a carboxyl functional group is acrylic acid (AA) can be

The (meth) acrylate-based resin is based on 100 parts by weight of the (meth) acrylate-based resin, 80 to 99 parts by weight of an alkyl (meth) acrylate monomer; And 1 to 30 parts by weight of a (meth)acrylate monomer having a hydroxyl or carboxyl functional group means that the alkyl (meth)acrylate monomer and the (meth)acrylate monomer having a hydroxyl or carboxyl functional group are in the above weight ratio It means merged.

In one embodiment of the present application, the (meth) acrylate-based resin is 80 to 99 parts by weight of an alkyl (meth) acrylate monomer, preferably 85 to 99 parts by weight, based on 100 parts by weight of the (meth) acrylate-based resin. part, more preferably 90 to 99 parts by weight.

In an exemplary embodiment of the present application, the (meth) acrylate-based resin is a (meth) acrylate-based resin based on 100 parts by weight, 1 to 30 parts by weight of a (meth) acrylate monomer having a hydroxyl or carboxyl functional group, preferably It may include 1 to 25 parts by weight, more preferably 1.5 to 10 parts by weight.

As the (meth)acrylate-based resin of the pressure-sensitive adhesive composition according to the present application satisfies the above weight part range, the pressure-sensitive adhesive film including the same can be prepared at low temperature (-20 ℃), room temperature (25 ℃), and high temperature (60 ℃). has an excellent creep recovery rate, and as the above range is satisfied, the folding characteristics of the foldable display are excellent and cracks do not occur.

That is, the creep recovery rate of the adhesive film according to an exemplary embodiment of the present application satisfies Equations 2 and 3 above so that it can be applied to a foldable display, and thus has excellent stress mitigation characteristics generated in the process of folding the foldable display. and has a feature capable of suppressing the occurrence of cracks, controlling the glass transition temperature of the (meth)acrylate-based resin and the type of each monomer constituting the (meth)acrylate-based resin included in the pressure-sensitive adhesive composition. Accordingly, it has characteristics capable of satisfying the creep recovery rate of the present application.

In one embodiment of the present application, the pressure-sensitive adhesive composition may further include a crosslinking agent, and the crosslinking agent may be 0.01 parts by weight or more and 0.5 parts by weight or less based on 100 parts by weight of the (meth)acrylate-based resin.

In another exemplary embodiment, the pressure-sensitive adhesive composition may further include a crosslinking agent, and based on 100 parts by weight of the (meth)acrylate-based resin, the crosslinking agent is 0.01 parts by weight or more and 0.5 parts by weight or less, preferably 0.03 parts by weight or more. It may be 0.3 parts by weight or less.

As the pressure-sensitive adhesive composition according to the present application includes the crosslinking agent by weight, the adhesive film has excellent cohesive strength, and creep characteristics also have characteristics that can satisfy Equations 2 and 3 according to the present application.

In one embodiment of the present application, the pressure-sensitive adhesive composition may further include one or more selected from the group consisting of a solvent, a dispersant, a photoinitiator, a thermal initiator, and a tackifier.

In one embodiment of the present application, the glass transition temperature (Tg) of the pressure-sensitive adhesive composition may be -55 ° C or more and 0 ° C or less.

According to an exemplary embodiment of the present specification, the crosslinking agent is hexanedioldi(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate having 2 to 14 ethylene groups, and trimethylolpropane. Di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, 2-trisacryloyloxymethylethylphthalic acid, the number of propylene groups 2 to 14 propylene glycol di(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, acidic variants of dipentaerythritol penta(meth)acrylate and dipentaerythritol Compounds obtained by esterifying polyhydric alcohols such as mixtures of hexa(meth)acrylates (trade names: TO-2348 and TO-2349 manufactured by Toga Synthetic Co., Ltd., Japan) with α,β-unsaturated carboxylic acids; compounds obtained by adding (meth)acrylic acid to compounds containing a glycidyl group, such as trimethylolpropane triglycidyl ether acrylic acid adducts and bisphenol A diglycidyl ether acrylic acid adducts; Ester compounds of polyhydric carboxylic acids with compounds having hydroxyl groups or ethylenically unsaturated bonds, such as phthalic acid diesters of β-hydroxyethyl (meth)acrylate and toluene diisocyanate adducts of β-hydroxyethyl (meth)acrylates , or adducts with polyisocyanates; (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; And 9,9'-bis [4- (2-acryloyloxyethoxy) phenyl] may include one or more selected from the group consisting of fluorene, but is not limited to these, known in the art Common ones can be used.

According to an exemplary embodiment of the present specification, the photoinitiator is a triazine-based compound, a biimidazole compound, an acetophenone-based compound, an O-acyloxime-based compound, a thioxanthone-based compound, a phosphine oxide-based compound, a coumarin-based compound and benzophenone It may be substituted with one or two or more substituents selected from the group consisting of paddy-based compounds.

Specifically, according to an exemplary embodiment of the present specification, the photoinitiator is 2,4-trichloromethyl-(4'-methoxyphenyl)-6-triazine, 2,4-trichloromethyl-(4'-methoxyphenyl) Toxystyryl) -6-triazine, 2,4-trichloromethyl- (fiplonil) -6-triazine, 2,4-trichloromethyl- (3', 4'-dimethoxyphenyl) -6 -triazine, 3-{4-[2,4-bis(trichloromethyl)-s-triazin-6-yl]phenylthio}propanoic acid, 2,4-trichloromethyl-(4'-ethyl ratio) triazine compounds such as phenyl)-6-triazine or 2,4-trichloromethyl-(4'-methylbiphenyl)-6-triazine; 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl biimidazole or 2,2'-bis(2,3-dichlorophenyl)-4,4',5 Biimidazole compounds, such as 5'-tetraphenyl biimidazole; 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethene Toxy)-phenyl (2-hydroxy)propyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenyl acetophenone, 2-methyl-(4-methylthiophenyl)-2-mol Acetopes such as polyno-1-propan-1-one (Irgacure-907) or 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one (Irgacure-369) paddy field compound; O-acyloxime compounds such as Ciba Geigy's Irgacure OXE 01 and Irgacure OXE 02; benzophenone compounds such as 4,4'-bis(dimethylamino)benzophenone or 4,4'-bis(diethylamino)benzophenone; thioxanthone-based compounds such as 2,4-diethyl thioxanthone, 2-chloro thioxanthone, isopropyl thioxanthone, or diisopropyl thioxanthone; 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide or bis(2,6-dichlorobenzoyl) propyl phosphine oxide phosphine oxide compounds such as the like; 3,3'-carbonylvinyl-7-(diethylamino)coumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 3-benzoyl-7-(diethylamino)coumarin, 3-benzoyl-7-methoxy-coumarin or 10,10'-carbonylbis[1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-Cl] A coumarin-based compound such as -benzopyrano[6,7,8-ij]-quinolizin-11-one may be used alone or in combination of two or more, but is not limited thereto.

In addition, as the thermal initiator, those known in the art may be used.

Although toluene may be used as the solvent, it is not limited thereto as long as it can dissolve a specific substance, and a general organic solvent may be used accordingly.

In one embodiment of the present application, the base film is PET (polyethylene terephthalate), polyester (polyester), PC (polycarbonate), PI (polyimide), PEN (polyethylene naphthalate), PEEK (polyether ether ketone), PAR ( polyarylate), polycylicolefin (PCO), polynorbornene, polyethersulphone (PES), and cycloolefin polymer (COP).

In another exemplary embodiment, the base film may be polyethylene terephthalate (PET).

In one embodiment of the present application, the thickness of the base film is 25 μm or more and 300 μm or less, preferably 30 μm or more and 270 μm or less, more preferably 40 μm or more and 250 μm or less.

Also, the base film is preferably transparent. The meaning here that the base film is transparent indicates that the light transmittance of visible light (400 to 700 nm) is 80% or more.

When the base film has the above range, the laminated adhesive film has characteristics capable of being thinned.

In one embodiment of the present application, the thickness of the adhesive sheet is 3 μm or more and 100 μm may be below.

In another exemplary embodiment, the thickness of the adhesive sheet is 3 μm or more and 100 μm or less, preferably 5 μm or more and 80 μm or less, more preferably 10 μm or more and 50 μm may be below.

When the thickness of the pressure-sensitive adhesive sheet is within the above range, the rate of air bubbles generated inside the pressure-sensitive adhesive sheet may be lowered, and the adhesion to the adherend substrate may be improved later.

In one embodiment of the present application, the thickness of the adhesive film is 110 ㎛ or more and 700 ㎛ The adhesive film which is the following is provided.

In another embodiment, the thickness of the adhesive film is 120 ㎛ or more and 600 ㎛ or less, preferably 125 μm or more and 550 μm or less, more preferably 130 μm or more and 500 μm may be below.

Since the adhesive film has the above range, the thickness is suitable when applied to a plastic organic light emitting display later, and cracks are prevented from occurring and lifting of the adhesive sheet even when folding and unfolding are repeated features that can be

In one embodiment of the present application, the pressure-sensitive adhesive sheet may be stacked in plurality.

In one embodiment of the present application, an adhesive film further comprising a release film is provided on the opposite side of the adhesive sheet in contact with the base film.

The release film may be a hydrophobic film and is a layer for protecting an adhesive sheet having a very thin thickness, and refers to a transparent layer attached to one surface of the adhesive sheet, and is a film having excellent mechanical strength, thermal stability, moisture barrier properties, and isotropy. can be used. For example, acetate-based, polyester-based, polyethersulfone-based, polycarbonate-based, polyamide-based, polyimide-based, polyolefin-based, cycloolefin-based, polyurethane-based and acrylic resin films such as triacetyl cellulose (TAC), etc. It can be used, but if it is a commercially available silicon-treated release film, it is not limited thereto.

2 is a diagram showing a laminated structure of an adhesive film including a release film according to an exemplary embodiment of the present application. Specifically, it can be confirmed that the adhesive film 40 has a structure in which the base film 10 / the adhesive sheet 20 / the release film 30 are sequentially stacked.

All of the release film may be removed when applied to a display.

An exemplary embodiment of the present application includes preparing a base film; and forming a pressure-sensitive adhesive sheet by applying and curing a pressure-sensitive adhesive composition on one surface of the base film,

After bonding the opposite side of the surface in contact with the base film of the adhesive sheet to stainless steel (SUS304 substrate), the initial adhesive strength after leaving it at 23°C for 3 hours is 200 gf/inch or less, and then heat-treated at 50°C for 20 minutes. Adhesion is over 800gf/inch,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at -20 ° C temperature is X1,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 25 ° C is X2,

The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 60 ° C is X3,

The X1 to X3 provide a method for producing an adhesive film that satisfies the following formulas 2 and 3.

[Equation 1]

[(F1-F2) / F1] X 100

[Equation 2]

X1/X2 > 0.9

[Equation 3]

X3/X2 > 1.0

In the above formula 1,

F1 means the strain generated by applying a shear force to the adhesive sheet for 10 minutes,

F2 means the strain after applying a shear force to the pressure-sensitive adhesive sheet for 10 minutes and recovering for 10 minutes at a shear force of 0 μNm.

In the manufacturing method, the base film, the pressure-sensitive adhesive composition, the initial adhesive strength, the late adhesive strength, the adhesive sheet, and the definitions of Formulas 1 to 3 are the same as described above.

In the present application, the pressure-sensitive adhesive sheet may be prepared by applying a pressure-sensitive adhesive composition on a base film with a bar coater.

In one embodiment of the present application, the pressure-sensitive adhesive composition is a (meth) acrylate-based resin; and a polymer having a melting temperature (Tm) of 30° C. or more, wherein the polymer is a copolymer of a monofunctional polysiloxane and at least one monomer, and the (meth)acrylate-based resin is a (meth)acrylate-based resin. Based on 100 parts by weight, 80 to 99 parts by weight of an alkyl acrylate monomer; and 1 to 30 parts by weight of an acrylate monomer having a hydroxy or carboxyl functional group.

An exemplary embodiment of the present application is an adhesive film according to the present application; and a plastic organic light emitting display provided on the adhesive sheet side of the adhesive film.

An exemplary embodiment of the present application is an adhesive film according to the present application; a plastic substrate provided on the side of the adhesive sheet of the adhesive film; and an IC chip provided on a surface opposite to a surface of the plastic substrate in contact with the adhesive film.

An exemplary embodiment of the present application includes a thin film transistor (TFT) provided on a surface opposite to a surface of the plastic substrate in contact with the adhesive film; and an organic light emitting layer on a surface opposite to a surface of the thin film transistor (TFT) in contact with the plastic substrate.

In the plastic organic light emitting display according to an exemplary embodiment of the present application, an anisotropic conductive film (ACF Anisotropic Conductive Film) may be further included on a surface of the IC chip in contact with the plastic substrate.

The anisotropic conductive film is a material for circuit connection in which conductive fine particles are uniformly dispersed in a film-like adhesive and has electrical anisotropy of conductivity in the thickness direction and insulation in the plane direction through a thermal compression bonding process.

The organic light emitting layer may be selected from the group consisting of an organic photoelectric device, an organic transistor, an organic solar cell, an organic light emitting device, and a micro LED device.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

< manufacturing example >

1. <Preparation of pressure-sensitive adhesive composition>

Pressure-sensitive adhesive compositions satisfying the composition of Table 1 below were prepared respectively.

( met ) acrylate type profit
(Glass transition temperature: Tg ) cross-linking agent
( parts by weight ) polymer polymer parts by weight Example One EHA:AA=98:2 (-69℃) BXX-5240
(0.03) STMA/FM-0721
(80:20) One Example 2 EHA:AA=98:2 (-69℃) BXX-5240
(0.03) STMA/FM-0721
(80:20) 3 Example 3 EHA:AA=98:2 (-69℃) BXX-5240
(0.05) STMA/FM-0721
(80:20) One Example 4 EHA:HBA=98:2 (-67℃) DR-7030HD
(0.1) STMA/FM-0721
(80:20) 3 Example 5 EHA:HBA=98:2 (-67℃) DR-7030HD
(0.3) STMA/FM-0721
(80:20) 3 Example 6 EHA:HBA=98:2 (-67℃) DR-7030HD
(0.4) STMA/FM-0721
(80:20) 3 comparative example One EHA:MMA:VP:HBA=65:20:5:10 (-33℃) DR-7030HD
(0.1) STMA/FM-0721
(80:20) 3 comparative example 2 EHA: VP:HBA=85:5:10 (-59°C) DR-7030HD
(0.1) STMA/FM-0721
(80:20) 3 comparative example 3 EHA:AA=98:2 (-69℃) BXX-5240
(0.03) - 0 comparative example 4 EHA:HBA=98:2 (-67℃) DR-7030HD
(0.6) STMA/FM-0721
(80:20) 3

In Table 1, EHA is 2-ethylhexyl acrylate, AA is acrylic acid, HBA is 4-hydroxybutyl acrylate, and MMA is methyl methacrylate Methylmethacrylate, VP is N-vinylpyrrolidone, STMA is stearyl methacrylate, and FM-0721 is a monofunctional polysiloxane manufactured by Chisso. is (meth)acrylate in which polysiloxane is present, BXX-5240 means an epoxy-based crosslinking agent, and DR-7030HD means an isocyanate-based crosslinking agent.

In Table 1, both the weight part of the crosslinking agent and the weight part of the polymer refer to 100 parts by weight of the (meth)acrylate-based resin in Table 1.

2. <Manufacture of adhesive film>

The adhesive compositions of Examples 1 to 6 and Comparative Examples 1 to 4 prepared above were coated on SKCKolonPI's polyimide film (GV200) at a dry thickness of 25 μm, dried at 120 ° C for 2 minutes, and then prevented from electrostatic charge on both sides. The adhesive composition coated with (Anti-static, AS) treated polyethylene terephthalate (PET) (RF12ASW) was covered. Thereafter, aging was performed at 40° C. for 2 days to prepare an adhesive film.

The physical properties of the prepared adhesive film were shown in Tables 2 and 3 below.

Creep % Recovery ( % ) Recovery Ratio -20℃ 25℃ 60℃ X1/X2 X3/X2 Example 1 84.9 83.9 90.9 1.01 1.08 Example 2 85.4 83.2 90.0 1.02 1.08 Example 3 82.9 84.3 89.8 0.98 1.06 Example 4 85.8 85.1 89.3 1.01 1.05 Example 5 82.0 83.7 89.0 0.98 1.06 Example 6 80.5 82.8 88.5 0.97 1.06 Comparative Example 1 54.3 79.7 83.5 0.68 1.05 Comparative Example 2 65.4 80.0 84.0 0.82 1.05 Comparative Example 3 84.4 83.8 90.4 1.01 1.08 Comparative Example 4 70.5 81.3 83.5 0.86 1.02

adhesiveness( SUS304 ) Rework characteristics Dynamic folding
(25℃, 2.5R , 100,000 times ) Early
(gf/inch) mid-term
(gf/inch) review
(gf/inch) Example 1 120 145 1180 OK OK Example 2 115 145 1150 OK OK Example 3 118 139 1120 OK OK Example 4 105 130 950 OK OK Example 5 110 138 900 OK OK Example 6 100 115 890 OK OK Comparative Example 1 50 54 1400 OK NG Comparative Example 2 60 65 1350 OK NG Comparative Example 3 960 1000 1050 NG OK Comparative Example 4 90 95 830 OK NG

One) Creep % Recovery ( % )

It was measured using TA Instrument's DHR (Discovery Hybrid Rheometer) HR-2 equipment, and after manufacturing a specimen with a thickness of 1 mm by overlapping the adhesive film several times, using a parallel plate fixture with a diameter of 8 mm Measure the strain (F1) generated by applying a shear force corresponding to a torque of 1005 μNm for 10 minutes (F1), and measure the strain after recovery for 10 minutes by setting the shear force to 0 μNm at the strain in that state ( F2), expressed as a ratio of "(F1-F2) / F1 X 100".

2) Initial adhesion

The initial adhesive force is measured by cutting the adhesive film into a size of 1 inch, reciprocating once with a 2kg rubber roller, attaching it to the SUS304 substrate, leaving it at 23℃ for 3 hours, and peeling at a 180° angle and a peeling speed of 300mm/min. and measured using a texture analyzer (Stable Micro Systems).

3) Middle term adhesion

The initial adhesive force is measured by cutting the adhesive film into a size of 1 inch, reciprocating once with a 2kg rubber roller, attaching it to the SUS304 substrate, leaving it at 23℃ for 24 hours, and peeling at a 180° angle and a peeling speed of 300mm/min. and measured using a texture analyzer (Stable Micro Systems).

4) Late adhesion

After cutting the adhesive film into a size of 1 inch, reciprocating once with a 2 kg rubber roller, attaching it to the SUS304 substrate, leaving it at 23 ° C for 3 hours, and then heat-treating at 50 ° C for 20 minutes at a 180 ° angle and 300 mm It was peeled at a peeling rate of /min and measured using a texture analyzer (Stable Micro Systems Inc.).

5) Rework characteristics

When the adhesive film was attached to the SUS304 substrate and peeled off after 10 minutes, if the adhesive film did not remain on the SUS substrate and fell off, it was indicated as OK, and if the residue of the adhesive film remained, it was indicated as NG.

6) Dynamic folding

After dynamic folding, if bubbles or delamination did not occur at the interface, it was marked as OK, and if it did occur, it was marked as NG.

As can be seen in Table 2 and Table 3, the adhesive films (Examples 1 to 6) according to an exemplary embodiment of the present application are polymers and (meth)acrylic polymers having a melting temperature (Tm) of 30° C. or higher in the adhesive sheet. It was confirmed that the adhesive sheet including the rate-based resin had a low initial adhesive strength with the substrate to be adhered. It was confirmed that the variable property was excellent as having a characteristic that sufficient adhesive force was expressed in order to do so.

Accordingly, it was confirmed that the adhesive films of Examples 1 to 6 had excellent rework properties because the adhesive strength of the adhesive sheet to the adherend substrate was initially maintained low, and no stains were left even when removed in case of erroneous attachment. .

In addition, the adhesive films of Examples 1 to 6 have creep recovery rates satisfying Equations 2 and 3 so that they can be applied to foldable displays, and thus have excellent stress mitigation characteristics generated in the process of folding the foldable display, It was confirmed that it had a feature capable of suppressing the occurrence of cracks, and accordingly, it had excellent creep recovery rates at low temperature, room temperature, and high temperature, and in the case of a plastic organic light emitting display including this, folding It was found that the characteristics had excellent characteristics.

In the case of Comparative Example 1 and Comparative Example 2 in Tables 2 and 3, the glass transition temperature of the (meth)acrylate-based resin is high and does not satisfy Equations 2 and 3, and in the case of a plastic organic light emitting display including the same, folding Due to poor folding characteristics, it was confirmed that bubbles or a lifting phenomenon occurred at the interface of the pressure-sensitive adhesive sheet.

In the case of Comparative Example 3 in Tables 2 and 3, Equations 2 and 3 according to the present application are satisfied, but the polymer having Tm characteristics is not included in the pressure-sensitive adhesive composition, and the adhesive strength is high in the early/middle/late stages of rework. It was confirmed that the characteristics were not good, and in particular, variable characteristics did not appear.

In the case of Comparative Example 4 of Tables 2 and 3, the content of the crosslinking agent contained in the pressure-sensitive adhesive composition exceeds a specific range, and variable properties are expressed, but do not satisfy the above formulas 2 and 3, In the case of the plastic organic light emitting display, it was confirmed that the folding property was not good, and bubbles were generated or a lifting phenomenon occurred at the interface of the adhesive sheet.

10: base film
20: adhesive sheet
30: release film
40: adhesive film

Claims (19)

base film; and
an adhesive sheet provided on one surface of the base film;
As an adhesive film containing,
The pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive composition or a cured product thereof,
The pressure-sensitive adhesive composition is a (meth) acrylate-based resin; And a polymer having a melting temperature (Tm) of 30 ° C or higher,
The polymer is a copolymer of a monofunctional polysiloxane and one or more monomers,
The (meth) acrylate-based resin is based on 100 parts by weight of the (meth) acrylate-based resin, 80 to 99 parts by weight of an alkyl (meth) acrylate monomer; And 1 to 20 parts by weight of a (meth)acrylate monomer having a hydroxyl or carboxyl group functional group,
After bonding the opposite surface of the surface in contact with the base film of the adhesive sheet to stainless steel (SUS304 substrate), the initial adhesive force after leaving it at 23 ° C for 3 hours is 50 gf / inch or more and 200 gf / inch or less, and heat-treated at 50 ° C. for 20 minutes The later adhesive strength is 800 gf / inch or more and 5,000 gf / inch or less,
The creep recovery rate (Creep recovery, %) represented by Equation 1 below at -20 ° C temperature is X1,
Creep recovery (%) represented by Equation 1 below at a temperature of 25 ° C is X2,
The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 60 ° C is X3,
X1 satisfies the following formula 4,
The X2 satisfies the following formula 5,
X3 satisfies the following formula 6,
[Equation 4]
80.0 < X1 < 90.0
[Equation 5]
80.0 < X2 < 90.0
[Equation 6]
85.0 < X3 < 95.0
An adhesive film in which X1 to X3 satisfy Equations 2 and 3 below:
[Equation 1]
ㅣ[(F1-F2) / F1]ㅣX 100
[Equation 2]
X1/X2 > 0.9
[Equation 3]
X3/X2 > 1.0
In the above formula 1,
F1 means the strain generated by applying a shear force to the adhesive sheet for 10 minutes,
F2 means the strain after applying a shear force to the pressure-sensitive adhesive sheet for 10 minutes and recovering for 10 minutes at a shear force of 0 μNm. The method of claim 1,
The adhesive film having a value of 5 or more and 100 or less of the value of the late adhesive force/initial adhesive force. The method of claim 1,
After bonding the opposite surface of the surface in contact with the base film of the adhesive sheet to stainless steel (SUS304 substrate), the intermediate adhesive strength after leaving at 23 ° C. for 24 hours is 55 gf / inch or more and 210 gf / inch or less. Adhesive film. delete delete The method of claim 1,
The monomer is an adhesive film represented by the following formula (1):
[Formula 1]

In Formula 1,
X is N or O;
R ₁ is hydrogen or a methyl group;
n is an integer from 1 to 30; The method of claim 6,
The monomer represented by Chemical Formula 1 is at least one selected from the group consisting of STA (Stearyl acrylate) and STMA (Stearyl methacrylate). The method of claim 1,
The polymer having a melting temperature of 30 ° C or higher is based on 100 parts by weight of the polymer having a melting temperature of 30 ° C or higher,
10 parts by weight or more and 40 parts by weight or less of the monofunctional polysiloxane, and
An adhesive film comprising 60 parts by weight or more and 90 parts by weight or less of the monomer. The method of claim 1,
The pressure-sensitive adhesive composition is based on 100 parts by weight of (meth) acrylate-based resin,
An adhesive film comprising 1 part by weight or more and 10 parts by weight or less of a polymer having a melting temperature of 30 ° C or higher. The pressure-sensitive adhesive film of claim 1, wherein the pressure-sensitive adhesive composition has a glass transition temperature (Tg) of -55°C or more and 0°C or less. The pressure-sensitive adhesive film of claim 1, wherein the pressure-sensitive adhesive composition further comprises at least one selected from the group consisting of a solvent, a dispersant, a photoinitiator, a thermal initiator, and a tackifier. The method according to claim 1, wherein the thickness of the pressure-sensitive adhesive sheet is 3 μm or more and 100 μm The adhesive film which is the following. The method according to claim 1, wherein the thickness of the base film is 25 ㎛ or more 300 ㎛ The adhesive film which is the following. The method according to claim 1, wherein the base film is PET (polyethylene terephthalate), polyester (polyester), PC (polycarbonate), PI (polyimide), PEN (polyethylene naphthalate), PEEK (polyether ether ketone), PAR (polyarylate), PCO An adhesive film selected from the group consisting of (polycylicolefin), polynorbornene, polyethersulphone (PES), and cycloolefin polymer (COP). The adhesive film of claim 1, further comprising a release film on the opposite side of the adhesive sheet in contact with the base film. Preparing a base film; and
Forming a pressure-sensitive adhesive sheet by applying and curing a pressure-sensitive adhesive composition on one surface of the base film;
As a method for producing an adhesive film comprising a,
The pressure-sensitive adhesive composition is a (meth) acrylate-based resin; And a polymer having a melting temperature (Tm) of 30 ° C or higher,
The polymer is a copolymer of a monofunctional polysiloxane and one or more monomers,
The (meth) acrylate-based resin is based on 100 parts by weight of the (meth) acrylate-based resin, 80 to 99 parts by weight of an alkyl (meth) acrylate monomer; And 1 to 20 parts by weight of a (meth)acrylate monomer having a hydroxyl or carboxyl group functional group,
The initial adhesive strength after bonding the opposite surface of the surface in contact with the base film of the adhesive sheet to stainless steel (SUS304 substrate) at 23 ° C. for 3 hours is 50 gf / inch or more and 200 gf / inch or less, and then at 50 ° C. for 20 minutes The late adhesive force after heat treatment is 800 gf / inch or more and 5,000 gf / inch or less,
The creep recovery rate (Creep recovery, %) represented by Equation 1 below at -20 ° C temperature is X1,
The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 25 ° C is X2,
The creep recovery rate (Creep recovery, %) represented by Equation 1 below at a temperature of 60 ° C is X3,
X1 satisfies the following formula 4,
The X2 satisfies the following formula 5,
X3 satisfies the following formula 6,
[Equation 4]
80.0 < X1 < 90.0
[Equation 5]
80.0 < X2 < 90.0
[Equation 6]
85.0 < X3 < 95.0
A method for producing an adhesive film in which X1 to X3 satisfy the following formulas 2 and 3:
[Equation 1]
[(F1-F2) / F1] X 100
[Equation 2]
X1/X2 > 0.9
[Equation 3]
X3/X2 > 1.0
In the above formula 1,
F1 means the strain generated by applying a shear force to the adhesive sheet for 10 minutes,
F2 means the strain after applying a shear force to the pressure-sensitive adhesive sheet for 10 minutes and recovering for 10 minutes at a shear force of 0 μNm. delete The pressure-sensitive adhesive film according to any one of claims 1 to 3 and 6 to 15; and
a plastic substrate provided on the side of the adhesive sheet of the adhesive film;
A plastic organic light emitting display comprising a. in claim 18
a liquid crystal display provided on a surface opposite to the surface of the plastic substrate in contact with the adhesive film; and
an organic light emitting layer on a surface opposite to the surface of the liquid crystal display in contact with the plastic substrate;
A plastic organic light emitting display comprising a.

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