KR20190019558A - Adhesive composition and protective sheet prepared from the same - Google Patents

Abstract

According to embodiments of the present invention, an adhesive composition contains a urethane-based resin and a solvent formed from a polyol and an isocyanate-based compound, and has an equivalence ratio (OH/NCO) of a predetermined range of a hydroxyl group of the polyol and an isocyanate group of the polyfunctional isocyanate compound. The adhesive composition can be effectively applied to, for example, a low-adhesive protective sheet of an image display apparatus.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure-sensitive adhesive composition and a protective sheet made therefrom,

The present invention relates to a pressure-sensitive adhesive composition and a protective sheet made therefrom, and more particularly to a pressure-sensitive adhesive composition comprising a pressure-sensitive adhesive resin and a protective sheet made therefrom.

In the manufacture of an image display device such as a liquid crystal display (LCD) device, an organic light emitting display (OLED) device, etc., the surface of various structures can be protected with a tacky sheet, for example, before a subsequent processing step or a subsequent bonding step.

The adhesive sheet may be peeled off again for subsequent processing, and static electricity may be generated at the time of peeling to cause disturbance of operation of the structure or the display channel. Therefore, the pressure-sensitive adhesive sheet needs to have an appropriate antistatic property.

Also, when the adhesive force or peeling force of the pressure sensitive adhesive sheet is excessively increased, for example, a display structure such as an OLED element may be damaged at the time of peeling off the adhesive sheet, and residues of adhesive components may be generated.

Further, it is preferable that the pressure-sensitive adhesive sheet stably maintain durability and stain resistance on the structure for a long period of time.

Korean Patent Laid-Open Publication No. 2004-0030919 (Apr. 04, 2004) discloses a method for producing a pressure-sensitive adhesive layer having a low surface resistivity by using an organic salt as an antistatic agent. However, the organic salt is expensive, It may not be secured.

Japanese Patent Laid-Open Publication No. 1994-128539 (Apr. 10, 1994) discloses a method of imparting antistatic properties by blending a polyether polyol with at least one alkali metal salt, but it is impossible to secure sufficient adhesion property as described above .

Korean Patent Publication No. 2004-0030919 Japanese Laid-Open Patent No. 1994-128539

An object of the present invention is to provide a pressure-sensitive adhesive composition which is capable of producing a protective sheet having improved folding characteristics, low sticking properties and mechanical stability.

An object of the present invention is to provide a protective sheet having an improved folding property, low sticking property and mechanical stability.

1. A pressure-sensitive adhesive composition comprising a urethane-based resin and a solvent formed from a polyol and a polyfunctional isocyanate compound, wherein the equivalent ratio (OH / NCO) of the hydroxy group of the polyol and the isocyanate group of the polyfunctional isocyanate compound is 1.5 to 4.

2. The pressure-sensitive adhesive composition according to 1 above, wherein the equivalent ratio (OH / NCO) of the hydroxyl group of the polyol and the isocyanate group of the polyfunctional isocyanate compound is 2 to 4.

3. The pressure-sensitive adhesive composition according to item 1 above, wherein the polyol has a weight average molecular weight of 2,500 or less.

4. The pressure-sensitive adhesive composition according to 1 above, wherein the polyol comprises at least one selected from the group consisting of a polycarbonate polyol, a polyester polyol, a polyether polyol and a polycaprolactone polyol.

5. The pressure-sensitive adhesive composition according to 1 above, wherein the polyfunctional isocyanate compound is a polyfunctional alicyclic isocyanate compound

6. The pressure-sensitive adhesive composition according to item 1 above, wherein the polyfunctional isocyanate compound has an isocyanate group arranged asymmetrically.

7. The pressure-sensitive adhesive composition according to 1 above, wherein the content of the urethane-based resin is 40 to 60% by weight of the total weight of the pressure-sensitive adhesive composition.

8. The pressure-sensitive adhesive composition according to 1 above, further comprising an antistatic agent.

9. The pressure-sensitive adhesive composition according to the above 8, wherein the antistatic agent comprises a metal cation and a salt of a fluorine-containing anion.

10. The pressure-sensitive adhesive composition according to the above 9, wherein the fluorine-containing anion comprises a (bis) fluorosulfonylimide anion.

11. The protective sheet formed from the pressure-sensitive adhesive composition according to any one of the above 1 to 10.

12. The protective sheet according to the above 11, which is provided for protecting the surface of the display element of the display panel.

The pressure-sensitive adhesive composition according to the above-described embodiments of the present invention satisfies the ratio of the equivalent ratio (OH / NCO) of the hydroxyl group and the isocyanate group to the predetermined value, and the folding property and the low- It is possible to prevent component residue. In addition, since it has improved aging stability, it can prevent bubbles and peeling, and can maintain stable durability for a long period of time.

In addition, the pressure-sensitive adhesive composition according to the exemplary embodiments can be applied to, for example, an organic light-emitting display (OLED) panel to provide a protective sheet with improved low adhesion and folding properties.

1 to 3 are sectional views for explaining a display panel or an image display device to which a protective sheet according to exemplary embodiments is applied.

According to embodiments of the present invention, the pressure-sensitive adhesive composition comprises a urethane-based resin and a solvent formed from a polyol and a polyfunctional isocyanate-based compound, wherein the equivalent ratio (OH / NCO) of the hydroxyl group of the polyol to the isocyanate group of the polyfunctional isocyanate compound May be about 1.5 to 4 hours. The pressure-sensitive adhesive composition can be effectively applied to, for example, a low-adhesive protective sheet of an image display apparatus.

Hereinafter, embodiments of the present invention will be described in detail.

≪ Pressure sensitive adhesive composition &

The pressure-sensitive adhesive composition according to embodiments of the present invention may include a urethane-based resin and a solvent.

The urethane-based resin can be obtained by curing a polyol and an isocyanate-based compound.

Non-limiting examples of the polyol include a polycarbonate polyol, a polyester polyol, a polyether polyol, and a polycaprolactone polyol. These may be used alone or in combination of two or more.

For example, the polycarbonate polyol may comprise a condensate of a polyol compound and a carbonic acid diester-based compound. The polyol compound may be at least one selected from the group consisting of ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl- Propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, , 8-octanediol, 1,8-decanediol, octadecanediol, and the like. These may be used alone or in combination of two or more.

The carbonic acid diester-based compound may include dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate and the like. These may be used alone or in combination of two or more.

The polycarbonate polyol may also comprise a copolymer with the condensate and additional compounds. The additional compound may include, for example, a carboxyl group-containing compound, a hydroxy group-containing compound, an ester-series compound and the like.

The polyester polyol may include, for example, a condensate with the polyol compound and the organic acid-based compound described above.

For example, the organic acid-based compound is selected from the group consisting of succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, terephthalic acid, phthalic acid, isophthalic acid, 4-naphthalene dicarboxylic acid, anhydrides thereof, and the like. These may be used alone or in combination of two or more.

The polyether polyol may include, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

The polycaprolactone polyol may include, for example, a polyester diol formed through ring-opening polymerization of? -Caprolactone and the like.

In some embodiments, the urethane-based resin may be formed or polymerized as a polyol, preferably comprising a polycarbonate polyol and / or a polycaprolactone polyol, more preferably a polycarbonate polyol. Therefore, it is expected that the low adhesion and folding properties of the pressure-sensitive adhesive composition can be further improved due to the three-dimensional molecular structure of the spolybrid orbitals possessed by the polyols described above, and the damage and residue residue of the object can be prevented during re- , Should not be construed as limited to these theories.

In some embodiments, the polyol may comprise a polyfunctional polyol, preferably a bifunctional polyol, having a weight average molecular weight (Mw) of 2,500 or less, preferably 1,500 to 2,500, And the folding property are further strengthened to prevent the residue in the re-peeling process and suppress the damage of the object.

The polyfunctional isocyanate-based compound may include a polyfunctional isocyanate compound that can be used for the urethanization reaction, for example, a polyfunctional aliphatic isocyanate compound, a polyfunctional alicyclic isocyanate, and a polyfunctional aromatic isocyanate compound. These may be used alone or in combination of two or more.

Examples of the polyfunctional aliphatic isocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3 -Butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and the like.

Examples of the polyfunctional alicyclic isocyanate compound include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane Diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanate methyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane. 4,4'-dicyclohexylmethane diisocyanate, and the like.

Examples of the polyfunctional aromatic isocyanate compound include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4 Tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, and 4,4'-diphenyl ether diisocyanate.

In some embodiments, the polyfunctional isocyanate compound may be a polyfunctional alicyclic isocyanate compound, and when the polyfunctional alicyclic isocyanate compound is used, the reaction rate is high when the urethane-based resin is formed with the polyol, The yellowing of the adhesive layer or the protective sheet can be effectively prevented.

In some embodiments, the polyfunctional isocyanate compound may be an isocyanate group asymmetrically arranged. For example, a plurality of isocyanate groups contained in the polyfunctional isocyanate compound can be arranged asymmetrically in the molecular structure, and each isocyanate group can be bonded to different polyol molecules, so that a urethane-based resin can be easily formed, (OH / NCO) of the hydroxyl group of the polyol and the isocyanate group of the polyfunctional isocyanate compound can be easily satisfied in the later-described range, so that the folding property and the low adhesion property of the protective sheet made of the pressure- have. As a non-limiting example of a polyfunctional isocyanate compound in which an isocyanate group is arranged in an asymmetric manner, isophorone diisocyanate can be mentioned.

According to exemplary embodiments, the equivalent ratio (OH / NCO) of the hydroxyl group of the polyol and the isocyanate group of the polyfunctional isocyanate compound may be about 1.5 to 4, and accordingly, the polyol and the urethane formed from the polyfunctional isocyanate compound It is possible to realize a protective sheet having excellent low adhesive property and folding property by controlling the degree of crosslinking of the series resin. The conversion ratio (yield) when the urethane-series resin is formed from the polyol and the polyfunctional isocyanate compound can be maintained at about 90% or more, for example, and the hydroxyl group contained in the polyol is not reacted Or react with an isocyanate group to form a urethane bond.

When the equivalent ratio is less than about 1.5, the protective sheet to be produced becomes too hard to lower the folding property, which may cause damage to the object, and the stability over time may be deteriorated. When the equivalence ratio is more than about 4, for example, unreacted polyol is increased to cause bubbling and peeling failure at the time of coating, and the durability of the protective sheet to be produced may be lowered.

In some embodiments, the equivalence ratio may preferably be about 2 to 4, and the desired low adhesion and folding properties can be preferably realized within the equivalence ratio range, so that damage to the object, Etc. can be effectively prevented.

The urethane-based resin may be contained in an amount of about 40 to 60% by weight based on the total weight of the pressure-sensitive adhesive composition.

If the content of the urethane-based resin is less than about 40% by weight, the mechanical durability or adhesive strength of the pressure-sensitive adhesive composition or the protective sheet may be excessively decreased, and the stability with time may be lowered. When the content of the urethane-based resin is more than about 60% by weight, it is difficult to substantially realize a low adhesive property, and the resistivity may be increased to deteriorate the antistatic property. Preferably, the content of the urethane-based resin may be about 45 to 60% by weight.

In some embodiments, the urethane-based resin may be formed by further including a catalyst for accelerating curing or crosslinking reaction of the polyol and the isocyanate-based compound.

The catalyst may include an organometallic compound in consideration of compatibility with a polyol. Non-limiting examples of such catalysts include iron acetylacetonate, iron 2-ethylhexanoate, dibutyl tin dichloride, dibutyl tin oxide, dibutyl tin dilaurate, dibutyl tin diacetate, dibutyl tin Sulfite, tributyltin methoxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloroacetate, di Butyl titanyl dichloride, tetrabutyl titanate, butoxy titanium trichloride, zirconium naphthenate, and zirconium acetylacetonate. These may be used alone or in combination of two or more.

In one embodiment, a polymerization inhibitor may be used to prevent an increase in adhesion due to an increase in the molecular weight of the urethane-based resin. The polymerization inhibitor may include, for example, a hydroquinone-based compound.

The solvent is widely used in the adhesive composition field and may include an organic solvent excellent in compatibility with the urethane-based resin. For example, organic solvents such as toluene, xylene, methyletol ketone, polyethylene glycol methyl ether acetate and the like can be used.

The solvent may include the remaining amount excluding the urethane-based resin and the antistatic agent, or the remaining amount excluding the urethane-based resin, the antistatic agent, and the additional agents described below.

The pressure-sensitive adhesive composition according to some embodiments may further include an antistatic agent in addition to the above-mentioned components.

The antistatic agent may comprise a metal-containing ionic solid. In exemplary embodiments, the antistatic agent may comprise a fluorine anion solid.

In this case, the antistatic agent may include a metal cation and a salt of a fluorine-containing anion. Examples of the metal cations include alkali metal cations such as lithium cations.

In some embodiments, the fluorine containing anion may comprise a (bis) fluorosulfonylimide anion.

By using the above-described fluorine anion solids, excellent resistance characteristics and antistatic properties can be realized even in a small amount. In some embodiments, the antistatic agent may be included in an amount of about 0.01 to 1% by weight based on the total weight of the pressure-sensitive adhesive composition.

When the content of the antistatic agent is less than about 0.01% by weight, sufficient antistatic properties may not be realized. If the content of the antistatic agent exceeds about 1% by weight, precipitation, bubbling or peeling of the antistatic agent may be caused. Preferably, in one embodiment, the antistatic agent may be used in an amount of about 0.01 to 0.03% by weight.

In addition, the use of the solid salt containing the (bis) fluorosulfonylimide anion can improve the compatibility with the urethane-based resin including the polyol. In addition, it is possible to prevent side effects such as leakage and denaturation in a high-temperature / high-humidity environment generated when a liquid type ionic compound is used.

In some embodiments, the pressure-sensitive adhesive composition may further comprise additional agents to the extent that the low sticking and folding properties are not degraded.

For example, the pressure-sensitive adhesive composition may further include additional agents such as a solvent, an antioxidant, a corrosion inhibitor, a leveling agent, a surface lubricant, a dye, a pigment, a defoamer, a filler and a light stabilizer.

The additional agent may be included in an amount of up to about 0.01% by weight of the total weight of the pressure-sensitive adhesive composition.

As described above, the pressure-sensitive adhesive composition according to the exemplary embodiments has improved low adhesive property and folding property, so that it is possible to prevent the damage of the object and the residue of the adhesive residue during re-peeling, Can be significantly lowered. In addition, it is possible to appropriately secure the required aging stability and mechanical reliability when applied as a protective sheet.

<Protective sheet, display panel, image display device>

1 to 3 are sectional views for explaining a display panel or an image display device to which a protective sheet according to exemplary embodiments is applied.

Referring to FIG. 1, the above-described pressure-sensitive adhesive composition is applied on at least one side of the base layer 60, and the pressure-sensitive adhesive layer 70 may be formed through, for example, a drying and / or curing process. The pressure-sensitive adhesive composition may be formed, for example, by a coating method such as roll coating, gravure coating, reverse coating, spray coating, air knife coating or die coater.

The substrate layer 60 may include, for example, plastic, paper, metal film, non-woven fabric, and the like. In one embodiment, the substrate layer 60 may comprise a plastic film such as a polyester-based resin, a polyamide-based resin, a polyimide-based resin, a polyolefin-based resin, a polyethylene terephthalate (PET)

Accordingly, a protective sheet in which the base layer 60 and the adhesive layer 70 are laminated can be produced, and the protective sheet can have low adhesion and folding properties through the pressure-sensitive adhesive composition.

In some embodiments, the base layer 60 may be formed on the upper and lower surfaces of the adhesive layer 70, respectively. For example, after removing the base layer 60 formed on the lower surface of the adhesive layer 70, the exposed surface of the adhesive layer 70 can be adhered to the display panel 50. Accordingly, the protective sheet may be provided as a surface protective sheet of the display panel 50. [

The display panel 50 may include, for example, a thin film transistor (TFT) substrate and a display element (for example, an OLED element or an LCD element) formed on the TFT substrate.

Referring to FIG. 2, the protective sheet may be peeled from the display panel 50 to laminate additional optical members or functional layers on the display panel 50.

As described above, the pressure-sensitive adhesive composition has an excellent antistatic property and a low adhesive peeling property, so that the pressure-sensitive adhesive composition can be peeled off without damaging the display device of the display panel 50. Further, since the pressure-sensitive adhesive composition has an improved stability over time, the display panel 50 can be protected by blocking the occurrence of lifting, bubbles, and the like after adhering to the display panel 50.

Referring to FIG. 3, the functional structure 80 may be laminated on one side of the display panel 50 from which the protective sheet is peeled off. The functional structure 80 may include optical structures such as a polarizing plate, a retardation film, a hard coating layer, a window film, and the like. In some embodiments, the functional structure 80 may include a touch sensor or touch screen panel.

When the protective sheet is directly applied to the display panel 50 as described with reference to FIGS. 1 to 3, in order to prevent disturbance or damage of the display device due to static electricity or adhesive residue, for example, An improved low adhesion property may be required compared to a protective sheet.

Therefore, a protective sheet having improved folding characteristics and low adhesive properties can be produced and applied using a pressure-sensitive adhesive composition that satisfies the equivalent ratio or content of functional groups according to the exemplary embodiments.

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. It will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments within the spirit and scope of the appended claims.

Examples and Comparative Examples

A polyfunctional isocyanate compound, a polyfunctional polyol, a catalyst, a polymerization inhibitor, an antistatic agent, and a solvent were placed in a 3 L four-necked flask equipped with an electronic stirrer, a heating mantle, a cooling tube and a temperature controller, . Specifically, the reaction temperature was raised to 40 ° C by self-heating while stirring the isocyanate compound, the polyol and the polymerization inhibitor, and when the temperature was maintained constant, the catalyst was added, and the temperature was gradually raised to 70 ° C to react for 6 hours. When the characteristic peak of NCO of 2250 cm ^{& lt} ; -1 ^{& gt;} peaks disappears in FT-IR, the reaction was terminated to prepare a urethane-based resin, and an antistatic agent was blended to prepare a pressure-

The prepared pressure-sensitive adhesive composition was coated on one side of a PET film (75 μm), dried in an oven at 80 ° C. for 2 minutes, and then a PET film (50 μm) treated with a silicone release treatment was bonded on the coating layer to form a protective sheet .

Example Comparative Example One 2 3 4 5 6 One 2 3 The polyol (A) A-1 400 600 - - 300 - 200 100 - A-2 - - 400 600 - - - - 1000 A-3 - - - - - 400 - - - Isocyanate
The compound (B) B-1 22 22 - - 22 22 22 22 - B-2 - - 26 26 - - - - 22 The catalyst (C) 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 The polymerization inhibitor (D) 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Antistatic agent (E) 12 12 12 12 12 12 12 12 12 Solvent (F) 435 635 440 635 435 435 235 135 1035 OH / NCO equivalent ratio 2 3 2 3 1.5 2 One 0.5 5 A-1: polycarbonate polyol (weight average molecular weight (Mw) = 2,000)
A-2: Polycaprolactone polyol (Mw = 2,000)
A-3: Polyethylene glycol (Mw = 2,000)
B-1: Isophorone diisocyanate (IPDI, Mw = 220)
B-2: 4,4'-Dicyclohexylmethane diisocyanate (Mw = 262)
C: Dibutyl tin dilaurate
D: methoxyhydroquinone
E: lithium bisfluorosulfonylimide
F: methyl ethyl ketone

Experimental Example

(1) Glass peel force

The protective sheets of Examples and Comparative Examples were cut into a size of 25 mm x 250 mm using a super cutter. Thereafter, a release film (PET film) was peeled off and specimens bonded to a glass plate were prepared. The specimen was fixed to a universal material testing machine (UTM), and then peeled off at 180 ^{° C} at a speed of 300 m / min to measure the peeling force against the glass.

(2) Liner (peeling force)

The protective sheets of the examples and comparative examples were cut using a super cutter to a size of 25 mm x 250 mm. The release film of the prepared specimen was partially peeled off, fixed on a universal testing machine (UTM), peeled off at 180 ° at a speed of 300 m / min, and peel strength was measured.

(3) Surface resistivity

Three points of the adhesive layer included in the protective sheet were measured ten times each using a surface resistivity meter (MCP-HT450, manufactured by Mitsuishi Chemical Co., Ltd.), and the surface resistivity was measured by the average value.

(4) Durability over time

The protective sheets of the examples and comparative examples were cut to a size of 300 mm x 220 mm, and a pressure of 5 kg / cm &lt; ² &gt; was applied to a glass of Corning # 1737 to form bubbles or foreign matter. The specimens were allowed to stand in an oven at 60 ° C for 7 days, and then bubbles or peeling occurred. The durability was evaluated according to the following criteria.

<Evaluation Criteria>

Ⓞ: No bubbles or peeling.

○: Bubbles or peeling <5

?: 5 pieces? Bubbles or peeling <10 pieces

X: 10 pieces &lt; bubble &

The evaluation results are shown in Table 2 below.

Referring to Table 2, it can be confirmed that the optical laminate made from the pressure-sensitive adhesive composition satisfying the OH / NCO equivalent ratio according to the above-described exemplary embodiments has excellent low adhesion and folding properties and excellent durability over time .

However, in Comparative Examples 1 to 3, which were outside the OH / NCO equivalent ratio range according to the examples, it was confirmed that the low sticking property and the folding property were not substantially realized, and the durability was extremely deteriorated.

50: Display panel
60: substrate layer
70: Adhesive layer
80: Functional structure

Claims (12)

A urethane-based resin and a solvent formed from a polyol and a polyfunctional isocyanate compound,
(OH / NCO) of the hydroxyl group of the polyol and the isocyanate group of the polyfunctional isocyanate compound is 1.5 to 4. The pressure-
The pressure-sensitive adhesive composition according to claim 1, wherein the equivalent ratio (OH / NCO) of the hydroxyl group of the polyol and the isocyanate group of the polyfunctional isocyanate compound is 2 to 4.
The pressure-sensitive adhesive composition according to claim 1, wherein the polyol has a weight average molecular weight of 2,500 or less.
The pressure-sensitive adhesive composition according to claim 1, wherein the polyol comprises at least one selected from the group consisting of a polycarbonate polyol, a polyester polyol, a polyether polyol, and a polycaprolactone polyol.
The pressure-sensitive adhesive composition according to claim 1, wherein the polyfunctional isocyanate compound is a polyfunctional alicyclic isocyanate compound
The pressure-sensitive adhesive composition according to claim 1, wherein the polyfunctional isocyanate compound has isocyanate groups arranged asymmetrically.
The pressure-sensitive adhesive composition according to claim 1, wherein the content of the urethane-based resin is 40 to 60 wt% of the total weight of the pressure-sensitive adhesive composition.
The pressure-sensitive adhesive composition according to claim 1, further comprising an antistatic agent.
The pressure-sensitive adhesive composition according to claim 8, wherein the antistatic agent comprises a salt of a metal cation and a fluorine-containing anion.
The pressure-sensitive adhesive composition according to claim 9, wherein the fluorine-containing anion comprises a (bis) fluorosulfonylimide anion.
A protective sheet formed from the pressure-sensitive adhesive composition according to any one of claims 1 to 10.
The protective sheet according to claim 11, which is provided for protecting the surface of a display element of a display panel.

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