Adhesive composition for protective film, adhesive containing the same, and adhesive sheet using the same

Abstract

The present invention relates to a pressure-sensitive adhesive composition for a protective film, a pressure-sensitive adhesive containing the same, and a pressure-sensitive adhesive sheet using the same. Specifically, the present invention relates to a pressure-sensitive adhesive composition for a protective film, which contains an oligomer-containing additive that is a polymerization reaction product of a mixture containing a hydrophilic monomer and a silicone-based monomer, thereby improving low-speed peel strength and high-speed peel strength, preventing adhesive residue when peeling a protective film, and reducing surface resistance and peel electrification voltage, a pressure-sensitive adhesive containing the same, and a pressure-sensitive adhesive sheet using the same.

Description

Technical Field

[0001] The present invention claims all the benefits of the filing date of Korean Patent Application No. 10-2020-0036046 filed with the Korean Intellectual Property Office on March 25, 2020, and the filing date of Korean Patent Application No. 10-2020-0036050 filed with the Korean Intellectual Property Office on March 25, 2020, and all of its contents are incorporated into the present invention. The present invention relates to an adhesive composition for a protective film, an adhesive containing the same, and an adhesive sheet using the same. Specifically, by including an oligomer-containing additive that is a polymerization reaction product of a mixture containing a hydrophilic monomer and a silicone-based monomer, it improves the low-speed peeling force and high-speed peeling force, prevents the adhesive from remaining when peeling the protective film, and can reduce the surface resistance and peeling charging voltage. The present invention relates to an adhesive composition for a protective film, an adhesive containing the same, and an adhesive sheet using the same.

Background Art

[0002] Protective films are widely used to prevent damage to the product surface caused by physical impacts that may occur during processes such as transportation, storage, and / or assembly of products such as home appliances, electronic products, optical elements, and automobiles.

[0003] Such protective films usually have a structure in which an adhesive layer is formed on one or both sides of a plastic base film such as polyethylene terephthalate. As an adhesive for forming the adhesive layer for the protective film, acrylic adhesives are widely used due to reasons such as weather resistance and transparency.

[0004] On the other hand, acrylic adhesives are also widely used for the purpose of attaching optical members such as polarizing plates, retardation plates, wide viewing angle compensation plates, and brightness enhancement films to display devices such as liquid crystal display devices.

[0005] Such protective films and optical components may require the removal of the adhesive sheet covering the protective film once their intended use is fulfilled or for replacement purposes. When removing the adhesive sheet from a polarizing plate, the adhesive contained in the adhesive layer is transferred to the polarizing plate, causing additional problems such as changes in the optical properties of the polarizing plate or, in certain environments, stains and other contamination. Furthermore, the TAC film provided at the outermost corner of the polarizing plate had the problem that the high-speed and low-speed peeling forces of the adhesive sheet covering the protective film and the charging characteristics due to peeling differed depending on whether or not the surface treatment was applied. In particular, there was a problem where the protective film would lift up after lamination of the protective film to the polarizing plate due to a decrease in low-speed peeling force.

[0006] Therefore, there is an urgent need to develop adhesive compositions for protective films that minimize static electricity generation and improve peeling strength even when the adhesive sheet is removed from the polarizing plate without lifting after lamination of the protective film, prevent the transfer of the adhesive, and do not contaminate the polarizing plate or alter its optical properties. This includes adhesives containing this composition and adhesive sheets using this composition. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The technical problem that the present invention aims to solve is to provide an adhesive composition for protective films, an adhesive containing the same, and an adhesive sheet using the same, which can prevent adhesive residue generated during the removal of the protective film from interfering with the optical properties of the polarizing plate or causing stains, minimize static electricity generated during the removal of the protective film, and improve low-speed peeling force.

[0008] However, the problems that this invention aims to solve are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0009] According to one embodiment of the present invention, an adhesive composition for protective films is provided, comprising: an acrylic polymer; one antistatic agent selected from a metal ion-containing inorganic salt, an ionic liquid organic salt, and a combination thereof; an isocyanate-based curing agent; and an oligomer-containing additive which is a polymer of a first mixture containing a first hydrophilic monomer of the following chemical formula 1 and a silicone monomer of the following chemical formula 3.

[0010] [ka]

[0011] R1 and R3 are hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms, respectively; R2 is a linear or branched alkylene group having 1 to 5 carbon atoms; and n is a natural number from 1 to 30.

[0012] [ka]

[0013] The R9 is a linear or branched alkylene group having 1 to 5 carbon atoms, and the R 10 m is a linear or branched alkyl group having 1 to 8 carbon atoms, and m is a natural number between 5 and 10.

[0014] One embodiment of the present invention provides an adhesive for protective films, which is a cured product of the adhesive composition. One embodiment of the present invention provides an adhesive sheet for a protective film, comprising a protective film and an adhesive, wherein the adhesive sheet includes an adhesive layer provided on one surface of the protective film. [Effects of the Invention]

[0015] An adhesive composition for protective films according to one embodiment of the present invention can improve the high-speed and low-speed peeling forces of adhesive sheets and can reduce the peeling voltage of adhesive sheets.

[0016] The adhesive for a protective film according to an embodiment of the present invention can prevent the transfer of the adhesive when peeling from a polarizing plate and can minimize the generation of static electricity.

[0017] The adhesive sheet for a protective film according to an embodiment of the present invention can prevent the change of the optical physical properties of the polarizing plate even when removed from the polarizing plate, and can prevent contaminants such as stains from adhering due to the static electricity of the polarizing plate.

[0018] The effects of the present invention are not limited to the effects described above, and the effects not mentioned will be clearly understood by those skilled in the art from the specification of the present application and the attached drawings.

Brief Description of the Drawings

[0019] [Figure 1] It is a schematic view of an adhesive sheet for a protective film according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0020] Throughout the specification of the present application, when a certain part states that a certain component "includes", this means that, unless otherwise stated to the contrary, it does not exclude other components, but can further include other components.

[0021] Throughout the specification of the present application, when it is stated that a certain member is "above" another member, this includes not only the case where a certain member is in contact with another member, but also the case where there are further other members between the two members.

[0022] Throughout the specification of the present application, the unit "parts by weight" can mean the weight ratio between each component. Throughout the specification of the present application, "(meth)acrylate" is used in the general sense of referring to acrylate and methacrylate. Throughout the specification of the present application, "A and / or B" means "A and B, or A or B".

[0023] Throughout this specification, the term "monomer unit" can mean a form obtained by a monomer reaction within a polymer, and more specifically, a form in which the monomer undergoes a polymerization reaction to form the backbone of the polymer, such as the main chain or side chains.

[0024] Throughout this specification, the "weight-average molecular weight" and "number-average molecular weight" of a compound are calculated using the molecular weight and molecular weight distribution of that compound. Specifically, a sample is prepared by placing tetrahydrofuran (THF) and the compound in a 1 ml glass bottle to obtain a sample with a compound concentration of 1 wt%. The sample and a standard sample (polystyrene) are filtered through a filter (pore size 0.45 μm), and then injected into a GPC injector. The elution time of the sample is compared with the calibration curve of the standard sample to obtain the molecular weight and molecular weight distribution of the compound. At this time, an Infinity II 1260 (Agilient) can be used as the measuring instrument, and the flow rate can be set to 1.00 mL / min and the column temperature to 40.0 °C.

[0025] Throughout this specification, the "glass transition temperature (Tg)" can be measured using differential scanning calorimetry (DSC). Specifically, using a DSC (Differential Scanning Calorimeter, DSC-STAR3, METTLER TOLEDO), the sample is heated at a rate of 5°C in the temperature range of -60°C to 150°C, and the experiment is carried out twice (cycles) in the aforementioned range. The glass transition temperature can then be determined by measuring the midpoint of the DSC curve created as a point where the amount of thermal change is significant.

[0026] The present invention will be described in more detail below. According to one embodiment of the present invention, an adhesive composition for protective films is provided, comprising: an acrylic polymer; one antistatic agent selected from a metal ion-containing inorganic salt, an ionic liquid organic salt, and a combination thereof; an isocyanate-based curing agent; and an oligomer-containing additive which is a polymer of a first mixture containing a first hydrophilic monomer of the following chemical formula 1 and a silicone monomer of the following chemical formula 3.

[0027] [ka]

[0028] R1 and R3 are hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms, respectively; R2 is a linear or branched alkylene group having 1 to 5 carbon atoms; and n is a natural number from 1 to 30.

[0029] [ka]

[0030] The R9 is a linear or branched alkylene group having 1 to 5 carbon atoms, and the R 10 m is a linear or branched alkyl group having 1 to 8 carbon atoms, and m is a natural number between 5 and 10.

[0031] An adhesive composition for protective films according to one embodiment of the present invention can improve the high-speed and low-speed peeling forces of adhesive sheets and can reduce the peeling voltage of adhesive sheets.

[0032] According to one embodiment of the present invention, the adhesive composition for protective films includes an acrylic polymer. Specifically, the acrylic polymer may be a polymer of a second mixture containing one selected from the group consisting of a first monomer which is a (meth)acrylate containing an alkyl group having 5 to 10 carbon atoms, a second monomer which is a (meth)acrylate containing an alkyl group having 1 to 4 carbon atoms, a third monomer which is a (meth)acrylate containing a polar group and an alkyl group having 1 to 3 carbon atoms, a fourth monomer which is a (meth)acrylate containing a polar group and an alkyl group having 4 to 6 carbon atoms, a fifth monomer which has chemical formula 1, and combinations thereof. By including an acrylic polymer which is a polymer of a second mixture containing the above monomers, the physical properties of the adhesive, which is the cured product of the adhesive composition for protective films, can be ensured.

[0033] According to one embodiment of the present invention, the second mixture may contain a first monomer which is a (meth)acrylate containing an alkyl group having 5 to 10 carbon atoms. Specifically, the second mixture contains a (meth)acrylate monomer containing an alkyl group having 5 to 9 carbon atoms, 6 to 8 carbon atoms, or 7 to 8 carbon atoms. Preferably, the first monomer of the (meth)acrylate containing an alkyl group having 5 to 10 carbon atoms may be 2-ethylhexyl acrylate. By adjusting the number of carbon atoms in the first monomer of the (meth)acrylate containing an alkyl group within the range described above, the glass transition temperature, hydroxyl value, and / or solids content of the acrylic polymer can be adjusted.

[0034] According to one embodiment of the present invention, the acrylic polymer may be a polymer of a second mixture containing 50% to 70% by weight of a first monomer which is a (meth)acrylate containing an alkyl group having 5 to 10 carbon atoms. Specifically, the first monomer is contained in the second mixture in amounts of 51% to 69% by weight, 52% to 68% by weight, 55% to 67% by weight, 58% to 66% by weight, or 60% to 65% by weight. Preferably, the first monomer is contained in the second mixture in amounts of 64% by weight. By adjusting the content of the first monomer within the above ranges, the glass transition temperature, hydroxyl value, and / or solids content of the acrylic polymer can be adjusted.

[0035] According to one embodiment of the present invention, the second mixture may contain a second monomer which is a (meth)acrylate containing an alkyl group having 1 to 4 carbon atoms. Specifically, the second mixture contains a (meth)acrylate monomer containing an alkyl group having 1 to 3 carbon atoms, 2 to 4 carbon atoms, 1 to 2 carbon atoms, 2 to 3 carbon atoms, or 3 to 4 carbon atoms. Preferably, the second monomer of the (meth)acrylate containing the alkyl group having 1 to 4 carbon atoms may be a butyl acrylate. By adjusting the number of carbon atoms in the second monomer of the (meth)acrylate containing the alkyl group within the range described above, the glass transition temperature, hydroxyl value, and / or solids content of the acrylic polymer can be adjusted.

[0036] According to one embodiment of the present invention, the acrylic polymer may be a polymer of a second mixture containing 20% ​​to 40% by weight of a second monomer which is a (meth)acrylate containing an alkyl group having 1 to 4 carbon atoms. Specifically, the second monomer is included in the second mixture in amounts of 21% to 39% by weight, 22% to 38% by weight, 23% to 37% by weight, 24% to 36% by weight, 25% to 35% by weight, 26% to 34% by weight, 27% to 33% by weight, 28% to 32% by weight, or 29% to 31% by weight. Preferably, the second monomer is included in the second mixture in an amount of 30% by weight. By adjusting the content of the second monomer within the above range, the glass transition temperature, hydroxyl value, and / or solids content of the acrylic polymer can be adjusted.

[0037] According to one embodiment of the present invention, the second mixture may contain a third monomer which is a (meth)acrylate comprising a polar group and a C1-C3 alkyl group. Specifically, the polar group may be a hydroxyl group or a carboxyl group, and the C1-C3 alkyl group may be a C1-C2 or C2-C3 alkyl group. Preferably, the third monomer which is a (meth)acrylate comprising a polar group and a C1-C3 alkyl group may be 4-hydroxyethyl acrylate. By selecting the polar group and alkyl group from those described above, the glass transition temperature, hydroxyl value and / or solids content of the acrylic polymer can be adjusted.

[0038] According to one embodiment of the present invention, the acrylic polymer may be a polymer of a second mixture containing 1.0% to 5.0% by weight of a third monomer, which is a (meth)acrylate containing a polar group and an alkyl group having 1 to 3 carbon atoms. Specifically, the third monomer is included in the second mixture in amounts of 0.3% to 4.7% by weight, 0.5% to 4.5% by weight, 0.8% to 4.3% by weight, 1.0% to 4.0% by weight, 1.5% to 3.5% by weight, 2.0% to 3.0% by weight, 2.1% to 2.9% by weight, 2.2% to 2.8% by weight, or 2.3% to 2.7% by weight. Preferably, the third monomer is included in the second mixture in an amount of 2.5% by weight. By adjusting the content of the third monomer within the above ranges, the glass transition temperature, hydroxyl value, and / or solids content of the acrylic polymer can be adjusted.

[0039] According to one embodiment of the present invention, the second mixture may contain a fourth monomer which is a (meth)acrylate comprising a polar group and a C4-C6 alkyl group. Specifically, the polar group may be a hydroxyl group or a carboxyl group, and the C4-C6 alkyl group may be a C4-C5 or C5-C6 alkyl group. Preferably, the fourth monomer which is a (meth)acrylate comprising a polar group and a C4-C6 alkyl group may be 4-hydroxybutyl acrylate. By selecting the polar group and alkyl group from those described above, the glass transition temperature, hydroxyl value and / or solids content of the acrylic polymer can be adjusted.

[0040] According to one embodiment of the present invention, the acrylic polymer may be a polymer of a second mixture containing 0.1% to 1.0% by weight of a fourth monomer, which is a (meth)acrylate containing a polar group and an alkyl group having 4 to 6 carbon atoms. Specifically, the fourth monomer is included in the second mixture in an amount of 0.2% to 0.9% by weight, 0.3% to 0.8% by weight, 0.4% to 0.7% by weight, or 0.5% to 0.6% by weight. Preferably, the fourth monomer is included in the second mixture in an amount of 0.5% by weight. By adjusting the content of the fourth monomer within the above range, the glass transition temperature, hydroxyl value, and / or solids content of the acrylic polymer can be adjusted.

[0041] According to one embodiment of the present invention, the second mixture may contain a fifth monomer having the following chemical formula 1 as the acrylic polymer.

[0042] [ka]

[0043] R1 and R3 are linear or branched alkyl groups having 1 to 5 carbon atoms, R2 is a linear or branched alkylene group having 1 to 5 carbon atoms, and n is a natural number from 1 to 30. Preferably, chemical formula 1 may be methoxypolyethylene glycol methacrylate. By including the fifth monomer from the above, the glass transition temperature, hydroxyl value, and / or solids content of the acrylic polymer can be adjusted.

[0044] According to one embodiment of the present invention, the second mixture may contain 1.0% to 5.0% by weight of the fifth monomer having chemical formula 1. Specifically, the fifth monomer is included in the second mixture in an amount of 1.5% to 4.5% by weight, 2.0% to 4.0% by weight, or 2.5% to 3.5% by weight. Preferably, the fifth monomer is included in the second mixture in an amount of 3.0% by weight. By adjusting the content of the fifth monomer within the above range, the glass transition temperature, hydroxyl value, and / or solids content of the acrylic polymer can be adjusted.

[0045] According to one embodiment of the present invention, the present invention comprises one antistatic agent selected from a metal ion-containing inorganic salt, an ionic liquid organic salt, and a combination thereof.

[0046] According to one embodiment of the present invention, an inorganic salt containing a metal ion may be included as an antistatic agent. Specifically, the metal ion may be an alkali metal. More specifically, the metal ion may be lithium, sodium, potassium, or rubidium. Furthermore, the anion contained in the inorganic salt may be one selected from the group consisting of bis(fluorosulfonyl)imide, bis(trifluorosulfonyl)imide, bis(trifluoromethanesulfonyl)imide, and combinations thereof. Preferably, the metal ion containing inorganic salt may be bis(trifluoromethanesulfonyl)imide lithium. By including the metal ion containing inorganic salt as described above, the surface resistance and peel voltage of the adhesive, which is the cured product of the adhesive composition, can be kept low, and the generation of static electricity can be prevented.

[0047] According to one embodiment of the present invention, an ionic liquid organic salt may be included as an antistatic agent. Specifically, the ionic liquid organic salt may include one or more cations selected from the group consisting of pyridinium, ammonium, pyrrolidinium, imidazolium, and phosphonium; and one or more anions selected from the group consisting of BF4, PF6, and TFSI. Preferably, the cation of the ionic liquid organic salt is pyridinium, and the anion may be bis(trifluoromethanesulfonyl)imide. By selecting the ionic liquid organic salt from those described above, the surface resistance and peel voltage of the adhesive, which is the cured product of the adhesive composition, can be kept low, and the generation of static electricity can be prevented.

[0048] According to one embodiment of the present invention, the content of the antistatic agent may be 0.1 parts by weight or more and 1.0 part by weight or less per 100 parts by weight of the acrylic polymer. Specifically, the content of the antistatic agent may be 0.1 parts by weight or more and 1.0 part by weight or less, 0.2 parts by weight or more and 0.0 part by weight or less, 0.3 parts by weight or more and 0.8 parts by weight or less, 0.4 parts by weight or more and 0.7 parts by weight or less, or 0.5 parts by weight or more and 0.6 parts by weight or less per 100 parts by weight of the acrylic polymer. Preferably, the content of the antistatic agent may be 0.5 parts by weight per 100 parts by weight of the acrylic polymer. By adjusting the content of the antistatic agent from the range described above, the surface resistance and peel voltage of the adhesive, which is the cured product of the adhesive composition, can be kept low, and the generation of static electricity can be prevented.

[0049] According to one embodiment of the present invention, the antistatic agent may contain the metal ion-containing inorganic salt in an amount of 0.1 to 1.0 part by weight per 100 parts by weight of the acrylic polymer. Specifically, the antistatic agent may contain the metal ion-containing inorganic salt in an amount of 0.2 to 0.9 parts by weight, 0.3 to 0.8 parts by weight, 0.4 to 0.7 parts by weight, 0.5 to 0.6 parts by weight, 0.2 to 0.6 parts by weight, or 0.2 to 0.5 parts by weight per 100 parts by weight of the acrylic polymer. Preferably, the antistatic agent may contain 0.5 parts by weight of the metal ion-containing inorganic salt per 100 parts by weight of the acrylic polymer. By adjusting the content of the metal ion-containing inorganic salt within the above range, the surface resistance and peel voltage of the adhesive, which is the cured product of the adhesive composition, can be kept low, and the generation of static electricity can be prevented.

[0050] According to one embodiment of the present invention, the ionic liquid organic salt may be present in an amount of 0.1 parts by weight or more and 1.0 part by weight or less per 100 parts by weight of the acrylic polymer. Specifically, the antistatic agent may contain the ionic liquid organic salt in an amount of 0.2 parts by weight or more and 0.9 parts by weight or less, 0.3 parts by weight or more and 0.8 parts by weight or less, 0.3 parts by weight or more and 0.7 parts by weight or less, 0.3 parts by weight or more and 0.6 parts by weight or less, or 0.3 parts by weight or more and 0.6 parts by weight or less per 100 parts by weight of the acrylic polymer. Preferably, the antistatic agent may contain 0.3 parts by weight of the ionic liquid organic salt per 100 parts by weight of the acrylic polymer. By adjusting the content of the ionic liquid organic salt within the above range, the surface resistance and peel voltage of the adhesive, which is the cured product of the adhesive composition, can be kept low, and the generation of static electricity can be prevented.

[0051] According to one embodiment of the present invention, an isocyanate-based curing agent is included. Specifically, it may include one or more selected from the group consisting of HDI trimmer, HMDI (Hexamethylene diisocyanate), TDI (Toluene diisocyanate), IPDI (Isophorone diisocyanate), and XDI (Xylylene diisocyanate), and combinations thereof. More specifically, toluene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, isophorone diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4-diisocyanate, 1,3-bisisocyanatomethylcyclohexane, tetramethylxylene diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-tri Methylhexamethylene diisocyanate, trimethylolpropane-modified toluene diisocyanate, trimethylolpropane-modified tolylene diisocyanate, trimethylolpropane tolylene diisocyanate adduct, trimethylolpropane xylene diisocyanate adduct, triphenylmethane triisocyanate, methylene bistriisocyanate, polyols of these (trimethylolpropane), or mixtures thereof may be used, but are not limited to these, and common polyols known in the art may be used.

[0052] According to one embodiment of the present invention, the curing agent may contain an isocyanate content of 10% or more and 20% or less. Specifically, the isocyanate content may be 11% or more and 19%, 12% or more and 18%, 13% or more and 17%, or 14% or more and 16% or less. By adjusting the isocyanate content within the above ranges, the degree of curing of the adhesive can be adjusted.

[0053] According to one embodiment of the present invention, the weight-average molecular weight of the curing agent may be 500 g / mol or more and 1,000 g / mol or less. Specifically, the weight-average molecular weight of the curing agent may be 600 g / mol or more and 900 g / mol or less, or 700 g / mol or more and 800 g / mol or less. By adjusting the weight-average molecular weight of the curing agent within the above range, the degree of curing and physical properties of the adhesive can be adjusted.

[0054] According to one embodiment of the present invention, the content of the isocyanate-based curing agent may be 1.0 part by weight or more and 9.0 parts by weight or less per 100 parts by weight of the acrylic polymer. Specifically, the content of the isocyanate-based curing agent may be 2.0 parts by weight or more and 8.0 parts by weight or less, 3.0 parts by weight or more and 7.0 parts by weight or less, 4.5 parts by weight or more and 6.0 parts by weight or less, or 3.5 parts by weight or more and 5.0 parts by weight or less per 100 parts by weight of the acrylic polymer. Preferably, the content of the isocyanate-based curing agent may be 3.5 parts by weight per 100 parts by weight of the acrylic polymer. By adjusting the content of the curing agent within the range described above, the degree of curing and physical properties of the adhesive can be adjusted.

[0055] According to one embodiment of the present invention, an oligomer-containing additive is a polymer of a first mixture containing a first hydrophilic monomer of the following chemical formula 1 and a silicone monomer of the following chemical formula 3;

[0056] According to one embodiment of the present invention, the first hydrophilic monomer of the following chemical formula 1 may also be used.

[0057] [ka]

[0058] R1 and R3 are hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms, respectively, R2 is a linear or branched alkylene group having 1 to 5 carbon atoms, and n may be a natural number from 1 to 30. Preferably, chemical formula 1 may be methoxypolyethylene glycol methacrylate. By selecting chemical formula 1 from those described above, the tackiness and peelability of the adhesive can be adjusted.

[0059] According to one embodiment of the present invention, the following silicone monomer of chemical formula 3 may also be used.

[0060] [ka]

[0061] The R9 is a linear or branched alkylene group having 1 to 5 carbon atoms, and the R 10 m is a linear or branched alkyl group having 1 to 8 carbon atoms, and m may be a natural number from 5 to 10. By selecting the above-mentioned chemical formula 3 from those described above, the adhesive strength and peeling strength of the adhesive can be adjusted.

[0062] According to one embodiment of the present invention, the content of the first hydrophilic monomer is 55 parts by weight or more and 85 parts by weight or less per 100 parts by weight of the first mixture. Specifically, the content of the first hydrophilic monomer may be 56 parts by weight or more and 84 parts by weight or less, 57 parts by weight or more and 83 parts by weight or less, or 58 parts by weight or more and 82 parts by weight or less per 100 parts by weight of the first mixture. Preferably, the content of the first hydrophilic monomer may be 60 parts by weight or more and 80 parts by weight or less per 100 parts by weight of the first mixture. By adjusting the content of the first hydrophilic monomer within the above range, the high-speed peeling force and low-speed peeling force of the adhesive which is the cured product of the adhesive composition for the protective film can be adjusted, and contamination can be minimized when removing the adhesive sheet from the polarizing film.

[0063] According to one embodiment of the present invention, the first mixture may further contain a second hydrophilic monomer of the following chemical formula 2.

[0064] [ka]

[0065] R4 may be hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms, R5 and R6 may be directly linked or a linear or branched alkylene group having 1 to 5 carbon atoms, R7 may be a linear or branched alkylene group having 1 to 5 carbon atoms, and R8 may be a linear or branched alkenylene group having 2 to 6 carbon atoms. Preferably, chemical formula 2 may be dicyclopentenyl methacrylate (DCPMA). By selecting chemical formula 2 from those described above, the tackiness and peeling force of the adhesive can be adjusted and the peeling voltage can be minimized.

[0066] According to one embodiment of the present invention, the content of the second hydrophilic monomer may be 50 parts by weight or more and 150 parts by weight or less per 100 parts by weight of the first hydrophilic monomer. Specifically, the content of the second hydrophilic monomer may be 55 parts by weight or more and 140 parts by weight or less, 60 parts by weight or more and 130 parts by weight or less, 65 parts by weight or more and 120 parts by weight or less, or 70 parts by weight or more and 100 parts by weight or less per 100 parts by weight of the first hydrophilic monomer. By adjusting the content of the second hydrophilic monomer within the above range, the adhesive strength and peeling strength of the adhesive can be adjusted and the peeling band voltage can be minimized.

[0067] According to one embodiment of the present invention, the content of the silicone monomer may be 50 parts by weight or more and 150 parts by weight or less per 100 parts by weight of the first hydrophilic monomer. Specifically, the content of the silicone monomer may be 55 parts by weight or more and 145 parts by weight or less, 60 parts by weight or more and 140 parts by weight or less, 65 parts by weight or more and 135 parts by weight or less, or 70 parts by weight or more and 130 parts by weight or less per 100 parts by weight of the first hydrophilic monomer. By adjusting the content of the silicone monomer within the above range, the adhesive strength and peeling strength of the adhesive can be adjusted and the peeling band voltage can be minimized.

[0068] According to one embodiment of the present invention, the content of the oligomer-containing additive may be 0.1 parts by weight or more and 1.0 part by weight or less per 100 parts by weight of the acrylic polymer. Specifically, the content of the oligomer-containing additive may be 0.1 parts by weight or more and 1.0 part by weight or less, 0.1 parts by weight or more and 0.9 parts by weight or less, 0.1 parts by weight or more and 0.8 parts by weight or less, 0.1 parts by weight or more and 0.7 parts by weight or less, 0.1 parts by weight or more and 0.6 parts by weight or less, or 0.1 parts by weight or more and 0.5 parts by weight or less per 100 parts by weight of the acrylic polymer. By adjusting the content of the oligomer-containing additive within the above range, the high-speed peeling force and low-speed peeling force of the adhesive which is the cured product of the adhesive composition for the protective film can be adjusted, contamination can be minimized when removing the adhesive sheet from the polarizing film, and the peeling band voltage can be minimized.

[0069] One embodiment of the present invention provides an adhesive for protective films, which is a cured product of the adhesive composition. An adhesive for protective films according to one embodiment of the present invention can prevent the adhesive from being transferred when peeled off from a polarizing plate, thereby minimizing the generation of static electricity. According to one embodiment of the present invention, the curing method may be thermal curing or photocuring, or is not limited to these, and any general method known in the art may be used.

[0070] One embodiment of the present invention provides an adhesive sheet for a protective film, comprising a protective film and an adhesive, wherein the adhesive sheet includes an adhesive layer provided on one surface of the protective film. An adhesive sheet for a protective film according to one embodiment of the present invention can prevent the optical properties of the polarizing plate from changing even when it is removed from the polarizing plate, and can prevent contaminants from adhering to the polarizing plate due to static electricity.

[0071] According to one embodiment of the present invention, a release film is provided on the side of the protective film opposite to the side on which the adhesive layer is provided. According to one embodiment of the present invention, a polarizing film is provided on the side of the protective film opposite to the side on which the adhesive layer is provided.

[0072] According to one embodiment of the present invention, the polarizing film is included. Specifically, the type of polarizing film used in the present invention is not particularly limited, and any common type known in the art can be used. For example, the polarizing film may include a polarizer and a protective film formed on one or both sides of the polarizer.

[0073] The type of polarizer included in the polarizing plate of the present invention is not particularly limited, and any common type known in this field, such as a polyvinyl alcohol-based polarizer, can be used without restriction.

[0074] A polarizer is a functional film or sheet that can extract only light vibrating in one direction from incident light vibrating in various directions. Such a polarizer may be in the form of a polyvinyl alcohol-based resin film on which a dichroic dye is adsorbed and oriented. The polyvinyl alcohol-based resin constituting the polarizer can be obtained, for example, by gelling a polyvinyl acetate-based resin. In this case, the usable polyvinyl acetate-based resin includes not only homopolymers of vinyl acetate, but also copolymers of vinyl acetate and other monomers copolymerizable with the same. Examples of monomers copolymerizable with vinyl acetate include, but are not limited to, one or more unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having ammonium groups. The degree of gelation of the polyvinyl alcohol-based resin is usually about 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. Furthermore, the degree of polymerization of the polyvinyl alcohol-based resin may be typically around 1,000 to 10,000, preferably around 1,500 to 5,000.

[0075] The polyvinyl alcohol-based resin described above can be used as a polarizer disc film by forming a film. The method for forming the polyvinyl alcohol-based resin film is not particularly limited, and general methods known in this field can be used.

[0076] The thickness of the disc film made from polyvinyl alcohol-based resin is not particularly limited and can be appropriately controlled within a range of, for example, 1 μm to 150 μm. Considering ease of stretching, the thickness of the disc film can be controlled to 10 μm or more.

[0077] Polarizers can be manufactured by processes such as stretching (e.g., uniaxial stretching) a polyvinyl alcohol-based resin film, dyeing the polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, treating the polyvinyl alcohol-based resin film with the adsorbed dichroic dye with an aqueous boric acid solution, and washing the film with water after treatment with the aqueous boric acid solution. Iodine and dichroic organic dyes can be used as the dichroic dye.

[0078] The polarizing film of the present invention may further include a protective film formed on one or both sides of the polarizer. The type of protective film included in the polarizing plate of the present invention is not particularly limited, and may be formed in a multilayer film in which protective films are laminated, for example, cellulosic films such as triacetylcellulose; polyester films such as polycarbonate films or polyethylene terephthalate films; polyethersulfone films; and / or polyolefin films such as polyethylene films, polypropylene films, or polyolefin films having a cyclo- or norbornene structure, or ethylene propylene copolymers. In this case, the thickness of the protective film is also not particularly limited and can be formed to an ordinary thickness.

[0079] On the other hand, the method for forming an adhesive layer on a polarizing film in the present invention is not particularly limited. For example, one could apply an adhesive composition (coating liquid) to the film or element using conventional means such as a bar coater and cure it, or apply the adhesive composition to the surface of a releaseable substrate and cure it, and then transfer the formed adhesive layer to the surface of the polarizing film or element.

[0080] In the present invention, it is preferable that the process of forming the adhesive layer be carried out after thoroughly removing volatile components or reaction residues, or other bubble-inducing components, from within the adhesive composition (coating liquid). This prevents problems such as excessively low crosslinking density or molecular weight of the adhesive, which reduces the elastic modulus and causes bubbles between the glass plate and the adhesive layer to enlarge and form scattering bodies inside at high temperatures.

[0081] According to one embodiment of the present invention, the present invention includes the above-mentioned adhesive and an adhesive layer provided on one surface of the protective film. The portion of the adhesive that overlaps with the above-mentioned description is omitted.

[0082] According to one embodiment of the present invention, the protective film can be a synthetic resin film such as polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, polyimide, polycarbonate, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene polypropylene copolymer, or polyvinyl chloride, and is not particularly limited.

[0083] According to one embodiment of the present invention, the protective film may consist of a single layer or a multi-layer structure, and its thickness may be 5 μm or more and 500 μm or less. According to one embodiment of the present invention, the surface of the protective film may be subjected to surface treatments such as corona discharge treatment, plasma treatment, blast treatment, chemical etching treatment, or primer treatment in order to improve adhesion to the adhesive layer.

[0084] According to one embodiment of the present invention, the adhesive layer is formed by applying the adhesive composition according to the present invention onto the substrate film and then drying it. The application can generally be carried out by a knife coater, roll coater, calender coater, comma coater, etc. Depending on the application thickness and the viscosity of the coating liquid, it can also be carried out by a gravure coater, rod coater, etc.

[0085] According to one embodiment of the present invention, the drying is carried out at a temperature of 60°C to 150°C, preferably 70°C to 120°C, for 1 to 10 minutes. The heat supplied in the drying step causes the solvent in the adhesive composition to volatilize, and the curing reaction between the curing agent and the acrylic polymer proceeds.

[0086] According to one embodiment of the present invention, if necessary, an aging step can be additionally performed after the drying step to complete the crosslinking reaction. The aging step is carried out, for example, for 1 to 7 days in a temperature range of 25°C to 90°C.

[0087] According to one embodiment of the present invention, the adhesive sheet may have a low-speed peeling force of 3.0 gf / in or more or 4.0 gf / in or more under the conditions of a peeling angle of 180° and a peeling speed of 0.3 m / min, and a high-speed peeling force of 60 gf / in or more under the conditions of a peeling angle of 180° and a peeling speed of 30 m / min, or a high-speed peeling force of 70 gf / in or more under the conditions of a peeling angle of 180° and a peeling speed of 30 m / min. Specifically, the adhesive sheet may have a low-speed peeling force of 3.0 gf / in or more and 4.5 gf / in or less, and a high-speed peeling force of 60 gf / in or more and 75 gf / in or less, or 60 gf / in or more and 70 gf / in or less. By achieving the high-speed and low-speed peeling forces of the adhesive sheet for protective film within the above ranges, it is possible to prevent the transfer of adhesive when removing the adhesive sheet from the polarizing plate and minimize contamination.

[0088] According to one embodiment of the present invention, the adhesive sheet may have a peeling band voltage of 0.30kV or less. Specifically, the adhesive sheet may have a peeling band voltage greater than 0kV and less than or equal to 0.30kV. By adjusting the peeling band voltage of the adhesive sheet within the above range, the static electricity generated on the polarizing plate can be minimized.

[0089] According to one embodiment of the present invention, the surface resistance is 9.99 × 10⁻⁶ 11 It may be less than or equal to Ω / □. Specifically, the surface resistance is 9.99 × 10⁻⁶ if it exceeds 0 Ω / □. 11By adjusting the surface resistance within the above-mentioned range of Ω / □ or less, static electricity generated by the adhesive sheet can be prevented. [Examples]

[0090] The present invention will be described in detail below with reference to examples. However, the examples of the present invention can be modified into various different forms, and the scope of the present invention should not be construed as being limited to the examples described below. The examples herein are provided to give a more complete explanation of the present invention to a person of average skill in the art.

[0091] Example 1-1 An acrylic polymer was produced by polymerizing a second mixture consisting of 64% by weight of 2-ethylhexylacrylate (2-EHA), the first monomer; 30% by weight of butyl acrylate (BA), the second monomer; 2.5% by weight of 2-hydroxyethyl acrylate (2-HEA), the third monomer; 0.5% by weight of 4-hydroxybutyl acrylate (4-HBA), the fourth monomer; and 3% by weight of methoxypolyethylene glycol methacrylate (MPEGMA), the fifth monomer.

[0092] Subsequently, an oligomer-containing additive was produced that contained a polymer obtained by polymerizing a first mixture, which was a mixture of 60 parts by weight of methoxypolyethylene glycol methacrylate (MPEGMA), a first hydrophilic monomer, and 40 parts by weight of a silicone monomer (Chisso Corp, FM-0711).

[0093] Subsequently, an adhesive composition for protective films was prepared, which was a mixture containing 100 parts by weight of the acrylic polymer, 0.5 parts by weight of LiTFSI [bis(trifluoromethanesulfonyl)imide]lithium as an antistatic agent, 3.5 parts by weight of an isocyanate curing agent (Samyoung Ink & Paint, DR-750HR), and 0.1 parts by weight of the oligomer-containing additive.

[0094] The adhesive composition for protective films was coated onto a PET film (TAK Corporation, XD510P) and dried to a thickness of 15 μm. This was then dried at 120°C for 2 minutes, after which the adhesive was covered with a release-treated PET film (TAK Corporation, XD7BR). Subsequently, the film was aged at 40°C for 2 days to produce an adhesive sheet for protective films.

[0095] Examples 1-2 An adhesive sheet for protective film was manufactured in the same manner as in Example 1-1, except that the content of the oligomer-containing additive was 0.3 parts by weight to produce the adhesive composition for protective film.

[0096] Examples 1-3 An adhesive sheet for protective films was manufactured in the same manner as in Example 1-1, except that an oligomer-containing additive was produced which included a polymer obtained by polymerizing a first mixture of 80 parts by weight of methoxypolyethylene glycol methacrylate (MPEGMA), a first hydrophilic monomer, and 20 parts by weight of a silicone monomer (Chisso Corp, FM-0711).

[0097] Examples 1-4 In Example 1-1, an adhesive sheet for protective film was manufactured in the same manner as in Example 1-1, except that an oligomer-containing additive was produced by polymerizing a first mixture obtained by mixing 80 parts by weight of methoxypolyethylene glycol methacrylate (MPEGMA), which is a first hydrophilic monomer, and 20 parts by weight of a silicone monomer (Chisso Corp, FM-0711), and the adhesive composition for protective film was manufactured with an oligomer-containing additive content of 0.3 parts by weight.

[0098] Comparative Example 1-1 In Example 1-1, an adhesive sheet for protective film was manufactured in the same manner as in Example 1-1, except that the adhesive composition for protective film was manufactured without the oligomer-containing additive.

[0099] Comparative Example 1-2 An adhesive sheet for protective films was manufactured in the same manner as in Example 1-1, except that an oligomer-containing additive was produced which included a polymer obtained by polymerizing a first mixture of 90 parts by weight of methoxypolyethylene glycol methacrylate (MPEGMA), a first hydrophilic monomer, and 10 parts by weight of a silicone monomer (Chisso Corp, FM-0711).

[0100] Comparative Examples 1-3 An adhesive sheet for protective films was manufactured in the same manner as in Example 1-1, except that an oligomer-containing additive was produced which included a polymer obtained by polymerizing a first mixture of 50 parts by weight of methoxypolyethylene glycol methacrylate (MPEGMA), which is a first hydrophilic monomer, and 50 parts by weight of a silicone monomer (Chisso Corp, FM-0711).

[0101] Test Example 1 (Measurement of Peeling Force) The plain and semi-glare (SG) treated surfaces of the TAC (Tri-Acetyl-cellulose) film were laminated with the protective film adhesive sheets produced in Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-3 using a 2 kg roll. After 24 hours, the low-speed peel force (gf / in) of the laminated adhesive sheet was measured at a peel angle of 180° and a peel speed of 0.3 m / min. The high-speed peel force (gf / in) was then measured under the same conditions at 30 m / min.

[0102] Test Example 2 (Contamination Assessment) The protective film adhesive sheets prepared in Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-3 were laminated onto the TAC (Tri-Acetyl-cellulose) film of the polarizing plate, and then left in a chamber at 60°C and 90% relative humidity for 3 days. After that, the protective film adhesive sheets were removed, and markings were arbitrarily left on the peeled polarizing plate using a dust-free cloth. Subsequently, when illuminated with a xenon lamp, it was evaluated as NG if the marked area was visible, and OK if the markings were not visible. The adhesive sheets for protective films manufactured in Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-3 are shown in Table 1 below, based on the results measured in Test Examples 1 and 2.

[0103] [Table 1]

[0104] Referring to Table 1, Examples 1-1 to 1-4 show that the content ratio of the first hydrophilic monomer to the silicone monomer in the first mixture is within 1.5:1 to 4:1, and the oligomer-containing additive, which is the polymerization product of the first mixture, is included in the adhesive composition for the protective film in an amount of 0.1 to 0.3 parts by weight, resulting in a low-speed peel force of 3.0 gf / in to 4.5 gf / in and a high-speed peel force of 60 gf / in to 75 gf / in, and it was confirmed that no contamination occurred in the contamination evaluation.

[0105] In contrast, in Comparative Example 1-1, contamination occurred because the oligomer-containing additive was not included in the adhesive composition for the protective film, failing to meet the contamination evaluation requirements, and resulting in an excessive increase in both high-speed and low-speed peeling forces. In Comparative Example 1-2, the use of an oligomer-containing additive containing an excessive amount of the first hydrophilic monomer failed to meet the contamination requirements, resulting in an excessive increase in both high-speed and low-speed peeling forces. In Comparative Example 1-3, the use of an oligomer-containing additive containing an excessive amount of the first hydrophilic monomer failed to meet the contamination requirements, resulting in an excessive decrease in low-speed peeling force.

[0106] Therefore, we confirmed that when the oligomer-containing additive is polymerized by adjusting the content of the first hydrophilic monomer and the silicone monomer, and at the same time the content of the oligomer-containing additive in the adhesive composition for protective films is adjusted to peel off the adhesive sheet, contamination can be minimized and both high-speed and low-speed peeling forces can be improved.

[0107] Reference Example 2-1 An acrylic polymer was produced by polymerizing a second mixture consisting of 64% by weight of the first monomer, 2-ethylhexyl acrylate (2-EHA), 30% by weight of the second monomer, butyl acrylate (BA), 2.5% by weight of the third monomer, 2-hydroxyethyl acrylate (2-HEA), 0.5% by weight of the fourth monomer, 4-hydroxybutyl acrylate (4-HBA), and 3% by weight of the fifth monomer, methoxypolyethylene glycol methacrylate (MPEGMA).

[0108] Subsequently, an oligomer-containing additive was produced by polymerizing a first mixture, which consisted of 30 parts by weight of methoxypolyethylene glycol methacrylate (MPEGMA), a first hydrophilic monomer; 30 parts by weight of dicyclopentenyl methacrylate (DCPMA), a second hydrophilic monomer; and 40 parts by weight of a silicone monomer (FM-0711).

[0109] Subsequently, a protective film adhesive composition was prepared, which was a mixture containing 100 parts by weight of the acrylic polymer, 0.5 parts by weight of LiTFSI[bis(trifluoromethanesulfonyl)imide]lithium as an antistatic agent, 0.3 parts by weight of the ionic liquid organic salt [bis(trifluoromethanesulfonyl)imide]pyridinium (Koei, IL-P14), 3.5 parts by weight of an isocyanate curing agent (Samyoung Ink & Paint, DR-750HR), and 0.1 parts by weight of the oligomer-containing additive.

[0110] The adhesive composition for protective films was coated onto a PET film (TAK Corporation, XD510P) and dried to a thickness of 15 μm. This was then dried at 120°C for 2 minutes, after which the adhesive was covered with a release-treated PET film (TAK Corporation, XD7BR). Subsequently, the film was aged at 40°C for 2 days to produce an adhesive sheet for protective films.

[0111] Reference Example 2-2 The aforementioned reference Except for the fact that in Example 2-1, the content of the oligomer-containing additive was 0.3 parts by weight to produce the adhesive composition for protective films, reference A protective film adhesive sheet was manufactured in the same manner as in Example 2-1.

[0112] Reference Example 2-3 The aforementioned referenceExcept for the fact that in Example 2-1, the adhesive composition for protective films was prepared with an oligomer-containing additive content of 0.5 parts by weight, reference A protective film adhesive sheet was manufactured in the same manner as in Example 2-1.

[0113] Reference Example 2-4 The aforementioned reference Except for the fact that in Example 2-1 an oligomer-containing additive was produced by polymerizing a first mixture obtained by mixing 40 parts by weight of methoxypolyethylene glycol methacrylate (MPEGMA), which is a first hydrophilic monomer, 30 parts by weight of dicyclopentenyl methacrylate (DCPMA), which is a second hydrophilic monomer, and 30 parts by weight of a silicone monomer (FM-0711), and an adhesive composition for protective films was produced with the oligomer-containing additive content set to 0.3 parts by weight, reference A protective film adhesive sheet was manufactured in the same manner as in Example 2-1.

[0114] Comparative Example 2-1 The aforementioned reference Except for the fact that in Example 2-1, the adhesive composition for protective films was manufactured without including the oligomer-containing additive, reference A protective film adhesive sheet was manufactured in the same manner as in Example 2-1.

[0115] Comparative Example 2-2 The aforementioned reference Except for the fact that in Example 2-1, a silicone-based additive (BYK-377) was used instead of the oligomer-containing additive to produce the adhesive composition for protective films, reference A protective film adhesive sheet was manufactured in the same manner as in Example 2-1.

[0116] Test Example 3 (Measurement of Peeling Force) The plain side and the semi-glare treated side of the TAC (Tri-Acetyl-cellulose) film are as follows: reference The adhesive sheets for protective films manufactured in Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2 were laminated using a 2 kg roll. After 24 hours, the low-speed peel force (gf / in) of the laminated adhesive sheet was measured at a peeling angle of 180° and a peeling speed of 0.3 m / min. The high-speed peel force (gf / in) was measured at 30 m / min under the same conditions using a Texture Analyer device.

[0117] Test Example 4 (Strip Voltage, ESD) ESD is the release band voltage measured when the release film is peeled off, and is measured using SHISHIDO's STATIRON DZ-4 model with a fixed length of 3 cm. reference After laminating the adhesive sheets of Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2 onto a release film, the peeling speed of the adhesive sheet was set to 30 m / min and the peeling angle to 180°, and the peeling voltage (kV) generated while peeling the adhesive sheet from each release film was measured.

[0118] Test Example 5 (Surface Resistance) Using a surface resistance meter (Mitsubishi Chemical Corporation, MCP-HT800), the above reference The surface resistance (Ω / □) of the adhesive sheets in Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2 was measured under conditions of an applied voltage of 100V and an applied time of 10 seconds. The aforementioned reference The results of the measurements taken in Test Examples 3 to 5 for the adhesive sheets for protective films manufactured in Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2 are summarized in Table 2 below.

[0119] [Table 2]

[0120] Refer to Table 2 above, reference Example 2-1~ referenceExamples 2-4 confirmed that when the oligomer-containing additive, which includes the first hydrophilic monomer, the second hydrophilic monomer, and the silicone monomer contained in the first mixture, is included in the adhesive composition for the protective film in an amount of 0.1 to 0.3 parts by weight, it has a low-speed peel force of 4.0 gf / in or more, a high-speed peel force of 70 gf / in or less, and a peel band voltage of 0.30 kV or less.

[0121] In contrast, Comparative Example 2-1, which did not contain the oligomer-containing additive, had the problem of a rapid increase in peeling band voltage and surface resistance. Comparative Example 2-2, which used a silicone-based additive instead of the oligomer-containing additive, also showed a rapid increase in peeling band voltage and surface resistance, and it was confirmed that the low-speed peeling force and high-speed peeling force did not have appropriate values.

[0122] Therefore, we confirmed that by selecting a specific first hydrophilic monomer, a second hydrophilic monomer, and a silicone-based monomer contained in the first mixture, and adjusting the content of the hydrophilic monomer and the silicone-based monomer to polymerize the oligomer-containing additive, while simultaneously adjusting the content of the oligomer-containing additive contained in the adhesive composition for protective films to peel off the adhesive sheet, it is possible to improve the high-speed peeling force and reduce the peeling band voltage.

[0123] Although the present invention has been described above by limited embodiments, it is understood that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical concept of the present invention and the claims described below by persons with ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0124] 10: Protective film 20: Adhesive layer 100: Adhesive sheet for protective film

Claims

1. Acrylic polymers; One antistatic agent selected from among metal ion-containing inorganic salts, ionic liquid organic salts, and combinations thereof; Isocyanate-based curing agents; and An oligomer-containing additive which is a polymer of a first mixture consisting of a first hydrophilic monomer of the following chemical formula 1 and a silicone monomer of the following chemical formula 3; The content of the first hydrophilic monomer is 55 parts by weight or more and 85 parts by weight or less per 100 parts by weight of the first mixture. The aforementioned acrylic polymer is a polymer of a second mixture containing 50% to 70% by weight of a first monomer which is a (meth)acrylate containing an alkyl group having 5 to 10 carbon atoms, 20% to 40% by weight of a second monomer which is a (meth)acrylate containing an alkyl group having 1 to 4 carbon atoms, 1.0% to 5.0% by weight of a third monomer which is a (meth)acrylate containing a polar group and an alkyl group having 1 to 3 carbon atoms, 0.1% to 1.0% by weight of a fourth monomer which is a (meth)acrylate containing a polar group and an alkyl group having 4 to 6 carbon atoms, and 1.0% to 5.0% by weight of a fifth monomer which has the following chemical formula A. Adhesive composition for protective film: 【Chemistry 1】 The aforementioned R １ and R ３ These are, respectively, hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms. The aforementioned R ２ This is a linear or branched alkylene group having 1 to 5 carbon atoms. The aforementioned n is a natural number between 1 and 30. 【Chemistry 2】 The aforementioned R ９ This is a linear or branched alkylene group having 1 to 5 carbon atoms. The aforementioned R １０ These are linear or branched alkyl groups having 1 to 8 carbon atoms. The aforementioned m is a natural number between 5 and 10. 【Transformation 3】 The aforementioned R １ and R ３ These are linear or branched alkyl groups having 1 to 5 carbon atoms, The aforementioned R ２ This is a linear or branched alkylene group having 1 to 5 carbon atoms. The aforementioned n is a natural number between 1 and 30. Note that R1 to R3 and n in chemical formula 3 are independent of each other from R1 to R3 and n in chemical formula 1.

2. The amount of the oligomer-containing additive is 0.1 parts by weight or more and 1.0 part by weight or less per 100 parts by weight of the acrylic polymer. The adhesive composition for protective films according to claim 1.

3. The content of the antistatic agent is 0.1 parts by weight or more and 1.0 part by weight or less per 100 parts by weight of the acrylic polymer. The adhesive composition for protective films according to claim 1.

4. The content of the isocyanate-based curing agent is 1.0 part by weight or more and 9.0 parts by weight or less per 100 parts by weight of the acrylic polymer. The adhesive composition for protective films according to claim 1.

5. An adhesive for protective films, which is a cured product of the adhesive composition described in claim 1.

6. Protective film and The adhesive is provided according to claim 5, and the protective film includes an adhesive layer provided on one side of the protective film. Adhesive sheet for protective film.

7. The low-speed peeling force at a peeling angle of 180° and peeling speed of 0.3 m / min is 3.0 gf / in (0.00116 N / mm) or higher. The high-speed peeling force at a peeling angle of 180° and a peeling speed of 30 m / min is 60 gf / in (0.0231 N / mm) or more. The adhesive sheet for protective film according to claim 6.

8. The stripping band voltage is 0.30 kV or less. The adhesive sheet for protective film according to claim 6.

9. The low-speed peeling force at a peeling angle of 180° and peeling speed of 0.3 m / min is 4.0 gf / in (0.00154 N / mm) or more. The high-speed peeling force at a peeling angle of 180° and a peeling speed of 30 m / min is between 60.0 gf / in (0.0232 N / mm) and 70.0 gf / in (0.0270 N / mm). The adhesive sheet for protective film according to claim 7.

10. The surface resistance is 9.99 × 10¹¹ Ω / □ or less. The adhesive sheet for protective film according to claim 6.

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