KR102146536B1 - Pressure-sensitive adhesive composition - Google Patents

Abstract

The present application provides a pressure-sensitive adhesive composition having excellent durability and excellent optical properties while implementing a high crosslinking density by functionalizing an unsaturated group in a rubber-based resin, and a protective film including the same.

Description

Adhesive composition {PRESSURE-SENSITIVE ADHESIVE COMPOSITION}

The present application relates to an adhesive composition, a protective film including the same, and a use thereof.

Rubber-based adhesives are a class of adhesive products that have a very wide range of applications. These pressure-sensitive adhesives can be applied for interior and exterior materials for displays, automobiles, or industrial applications. Rubber-based adhesives are flexible and can be applied to various surfaces, and they are adhesives with excellent price competitiveness, but are difficult to have internal crosslinking such as acrylic adhesives, so heat resistance and chemical resistance are inferior, and UV stability and transparency are reduced due to remaining unsaturated groups. It has the disadvantages that it is not easy.

Conventionally, there have been attempts to introduce internal crosslinking or introducing a functional group through vulcanization using an unsaturated group of a rubber-based adhesive, but it has a disadvantage that it is not easily applied because there are many parts that require washing and purification when introducing a functional group.

The present application provides a pressure-sensitive adhesive composition having excellent durability and excellent optical properties while implementing a high crosslinking density by functionalizing an unsaturated group in a rubber-based resin, and a protective film including the same.

The present application relates to an adhesive composition. The pressure-sensitive adhesive composition may be applied for, for example, a heat-resistant protective film for a touch or a protective film for an organic electronic device process.

An exemplary pressure-sensitive adhesive composition may include a base resin. The base resin may include an olefin-based compound. The base resin may also have an unsaturated group of 20 to 90 mol%, more than 20 mol%, 90 mol% or less, or 30 mol% to 90 mol%. In addition, the base resin may include at least one or more reactive functional groups derived from the unsaturated group. The present application may improve durability such as heat resistance and ozone resistance of the pressure-sensitive adhesive by adjusting the range of the unsaturated group content of the base resin. In the present specification, the meaning of "derived" means that a reactive functional group can be formed from the unsaturated group, and specifically, it may mean that a compound having a functional group is polymerized with an unsaturated group or an unsaturated group is epoxidized. In one example, the conversion rate of the unsaturated group of the base resin to the reactive functional group may be 70%, 80%, or 90% or more, and the upper limit is not limited, and may be 100% or 99%. That is, the conversion rate of the unsaturated group to the reactive functional group may be kept high within the above range, and thus, the unsaturated group of the base resin may hardly be present in the resin. In the present application, by controlling the content of the unsaturated group of the base resin and the conversion rate of the unsaturated group to the reactive functional group within the above range, it is possible to improve the compatibility of the resin and implement a high crosslinking density while implementing excellent durability. In the present application, the content ratio of the unsaturated group of the base resin and the conversion rate of the unsaturated group to the reactive functional group can be measured through NMR, and the measurement examples are described in Examples.

When the pressure-sensitive adhesive composition is prepared as a film, the adhesive strength (measurement temperature: 23°C, peel rate: 300mm/min, peel angle: 180°) to the alkali-free glass after curing is 20 gf/in or less, 3 to 15 gf/in or 6 To 15 gf/in. The present application can provide a protective film having excellent reworkability and no residue upon peeling since the pressure-sensitive adhesive is applied as a film within the adhesive strength range.

In one example, the base resin may have an integration ratio (R) of hydroxyl groups represented by the following general formula 1 of 10% or less, 5% or less, or 1% or less.

[General Formula 1]

R=H/(E+H)×100

In the general formula 1, E represents the area (integration) of the peak resulting from the reactive functional group in ¹ H-NMR, and H represents the area of the peak resulting from the hydroxyl group (integration).

The lower limit of the hydroxyl group area ratio (integration ratio, R) may be 0%. The measurement method of ¹ H-NMR is not particularly limited, and can be performed in a known manner. For example, when the peaks derived from each of the reactive functional groups and hydroxyl groups do not overlap each other as a result of the NMR measurement, it can be obtained through the area of the corresponding peak, and when the peaks overlap each other, the ratio can be calculated by considering the overlapping portions. have. Various analysis programs that can obtain the area of a peak by analyzing ¹ H-NMR spectrum are known. For example, the area of the peak can be calculated using the MestReC program. For example, ¹ H-NMR analysis can be performed at room temperature using an NMR spectrometer including a Varian Unity Inova (500 MHz) spectrometer having a triple resonance 5 mm probe. The analyte may be diluted to a concentration of about 10 mg/ml in a solvent for NMR measurement (CDCl ₃ ). ^{In the 1} H-NMR spectrum, according to the above-described General Formula 1, the area ratio (integration ratio, R) of the hydroxyl group can be measured. The area of the peak can be calculated using the MestReC program.

In one example, the base resin may be a homopolymer derived from an olefinic compound or a copolymer in which other polymerizable monomers are polymerized together. The present application controls the integration ratio of the hydroxyl groups of the base resin within the above range, thereby introducing a reactive functional group into the resin in a desired range to provide excellent moisture barrier properties, while also implementing heat resistance and durability reliability and optical properties at high temperature and high humidity. Can maintain excellent at the same time.

In addition, as described above, the polymer may have at least one reactive functional group. The reactive functional group may be in a form in which the unsaturated group of the base resin is epoxidized. In one example, the reactive functional group may be a form in which the unsaturated group of the main chain of the base resin is epoxidized. In another embodiment, the reactive functional group may be in the form of epoxidation of the unsaturated group of the side-chain bonded organic group of the base resin. The side chain-bonded organic group may have a cyclic structure having 3 to 20, 4 to 15, or 5 to 12 carbon atoms. In the present application, by using a base resin having a reactive functional group, it is possible to achieve excellent moisture barrier properties while maintaining excellent heat resistance, durability reliability and optical properties at high temperature and high humidity at the same time.

In the embodiment of the present application, the base resin includes a resin derived from a mixture of monomers, and the mixture may include an olefin-based compound. The olefinic compound may have an isoolefin monomer component or a multiolefin monomer component having at least 4 to 7 carbon atoms. The isoolefin may be present, for example, in a range of 70 to 100% by weight, or 85 to 99.5% by weight, based on the total monomer weight. The multiolefin-derived component may be present in the range of 0.5 to 30% by weight, 0.5 to 15% by weight, or 0.5 to 8% by weight.

Isoolefin is, for example, styrene, isobutylene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 1-butene, 2-butene, methyl, vinyl ether , Indene, vinyltrimethylsilane, hexene, or 4-methyl-1-pentene may be exemplified. The multiolefin may have 4 to 14 carbon atoms, for example isoprene, butadiene, 2,3-dimethyl-1,3-butadiene, myrcene, 6,6-dimethyl-fulbene, hexadiene, cyclopentadiene, or Piperylene can be illustrated. Other polymerizable monomers such as styrene and dichlorostyrene may also be homopolymerized or copolymerized.

In the present application, the base resin may include an olefin-based compound homopolymer or copolymer. As mentioned above, the isobutylene-based olefin-based resin or polymer may mean an olefin-based resin or polymer comprising at least 70 mol% of repeating units and at least one other polymerizable unit from isobutylene or isoprene.

In the present application, the base resin may be a butyl rubber or a branched butyl rubber. Exemplary, the base resin is an unsaturated butyl rubber such as an olefin or a copolymer of an isoolefin and a multiolefin. As the base resin included in the pressure-sensitive adhesive composition of the present invention, styrene-isoprene-styrene copolymer, poly(isobutylene-co-isoprene), polyisoprene, polybutadiene, polyisobutylene, poly(styrene-co-butadiene), Natural rubber, butyl rubber, and mixtures thereof may be exemplified.

In one example, the base resin may include a polymer in which a reactive functional group is side-chain bonded by grafting a compound having a polymerizable functional group to a polymer derived from an olefin-based compound. The polymerizable functional group may be, for example, a carbon-carbon double bond, an acryloyl group or a methacryloyl group.

In a specific example of the present application, the reactive functional group may be an epoxy group, and specifically, the unsaturated group of the base resin may be an epoxidized epoxy group. The unsaturated group can be, for example, a carbon-carbon double bond. In one example, the epoxidation may refer to a reaction in which one atom of oxygen is added to an ethylene bond to generate 1,2-epoxide.

The epoxidation can be carried out using an oxidizing agent. The oxidizing agent may be a known oxidizing agent capable of epoxidation, and examples thereof include organic peroxides such as hydrogen peroxide, performic acid, peracetic acid, trifluoroperacetic acid, perbenzoic acid, metachloroperbenzoic acid (mCPBA), and dimethyldioxane; Oxo complexes such as salen complexes; Peroxide salts such as magnesium monoperoxyphthalate and oxone may be used, and in detail, from the viewpoint of reaction efficiency, peroxide salts may be used. In the present application, when the base resin is epoxidized using a peroxide salt, an epoxy group may be introduced into an unsaturated group even at a low acidity, thereby minimizing the problem of forming a hydroxyl group through a side reaction that may occur at a high acidity.

In another example, the base resin may have an epoxy equivalent in the range of 100g/eq to 20,000g/eq. As described above, the base resin may include a reactive functional group, and when the reactive functional group is an epoxy group, the epoxy equivalent may be controlled within the above range. The present application provides a highly reliable adhesive by controlling the epoxy equivalent of the base resin within the above range, thereby increasing internal stress by forming a dense crosslinking density and realizing excellent transparency.

In one example, the base resin in the present application is, for example, the base resin is about 100,000 to 1 million, more than 100,000 to less than 900,000, 150,000 to 800,000, 200,000 to 700,000, or 200,000 It may have a number average molecular weight of about 650,000 to. In the present application, by controlling the number average molecular weight of the base resin within the above range, it is possible to maintain excellent heat resistance, durability reliability, and optical properties at a high temperature and high humidity after being applied as an adhesive.

In a specific example of the present application, the pressure-sensitive adhesive composition may have an annular structure after curing. The cyclic structure may be derived from a base resin. In the present application, by implementing the adhesive having the above structure, even after crosslinking or curing, a crosslinked structure that is stable against external factors such as contraction and expansion can be implemented.

In one example, the pressure-sensitive adhesive composition of the present application may not include a curable compound. Typical pressure-sensitive adhesive compositions use a separate curable compound to form a dense crosslinking density, but such a curable compound may have limitations in maintaining compatibility with the base resin, and thus, excellent optical properties when manufactured as a film. It can be difficult to obtain characteristics. In contrast, the pressure-sensitive adhesive composition according to the present application can form a dense crosslinked structure even without using a separate curable compound by including the specific base resin described above, thereby securing excellent optical properties and at the same time excellent moisture barrier properties. And it can be made of a film excellent in durability.

In one example, the curable compound not included in the pressure-sensitive adhesive composition of the present application may be, for example, a compound having a curable functional group. The curable functional group may be a glycidyl group, an isocyanate group, a hydroxy group, a carboxyl group, an amide group, an epoxide group, a cyclic ether group, a sulfide group, an acetal group or a lactone group. In the embodiment of the present application, the curable compound may be an epoxy compound or a polyfunctional acrylate.

Specifically, the 　 polyfunctional 　 acrylate may be, for example, tricyclodecane dimethanol di(meth)acrylate, but is not limited thereto.

In addition, as the 　epoxy　 compound, for example, 　epoxylated linseed oil, 　epoxylated polybutadiene, polyisobutylene oxide, α-pinene oxide, limonene dioxide, 3,4-epoxycyclohexylmethyl -3,4-epoxycyclohexane carboxylate, tri-cyclodecane di-methanol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether and 1,2-bis[(3-ethyl-3-oxe) One kind or two or more kinds of tanyl methoxy)methyl]benzene may be exemplified, but are not limited thereto.

In one example, the pressure-sensitive adhesive composition of the present application may further include a tackifier. The tackifier may be a resin produced by reacting a terpene compound and an aromatic compound. In addition, the aromatic compound may include a reactive functional group, and examples of the functional group include a hydroxy group, a carboxyl group, and an amine group. The present application may improve the crosslinking density of the entire pressure-sensitive adhesive due to the reactive functional group. Specifically, the aromatic compound may be phenol, and the tackifier may be a terpene phenolic resin. In the present application, by using the terpene phenolic resin as a tackifier, it is possible to provide an adhesive having excellent durability and reliability by improving not only excellent adhesive strength but also crosslinking density.

The tackifier may be a resin produced by reacting a terpene compound and a phenol compound. The terpene compound may mean a compound having a basic skeleton (C ₅ H ₈ )n in which two or more isoprenes (C ₅ H ₈ ) are bound. In the above, n may be 2 or more. In the above, the terpene compound may be at least one selected from the group consisting of α-pinene, β-pinene, δ-3-karene, 3-karene, D-limonene and dipentene. In addition, the phenolic compound is phenol, 4-t-butylphenol (para-tert-butylphenol; PTBP), 4-t-octylphenol (para-tert-octhylphenol; PTOP), 4-n-pentylphenol (para-n -pentyl phenol; PNPP) and 4-n-hexyl phenol (para-n-hexyl phenol; PNHP) may be at least one selected from the group consisting of.

The tackifier is 10 to 100 parts by weight, 20 to 90 parts by weight, 30 to 90 parts by weight, 30 to 80 parts by weight, 35 to 70 parts by weight, 35 to 60 parts by weight or 38 to based on 100 parts by weight of the base resin. It may be included in 50 parts by weight. Within the weight range, the pressure-sensitive adhesive may satisfy physical properties required for the protective film.

In a specific example of the present application, the pressure-sensitive adhesive composition may further include a curing agent or an initiator according to the type of the base resin. For example, it may further include a curing agent capable of forming a crosslinked structure or the like through the above-described base resin or a cationic initiator capable of initiating a curing reaction. As the cationic initiator, a cationic photopolymerization initiator or a cationic thermal initiator can be used.

As the curing agent, as an epoxy curing agent known in the art, for example, one or more types of an amine curing agent, an imidazole curing agent, a phenol curing agent, a phosphorus curing agent, or an acid anhydride curing agent may be used, but is not limited thereto. .

In one example, as the curing agent, an imidazole compound having a solid state at room temperature and a melting point or decomposition temperature of 80° C. or higher may be used. Such compounds include, for example, 2-methyl imidazole, 2-heptadecyl imidazole, 2-phenyl imidazole, 2-phenyl-4-methyl imidazole, or 1-cyanoethyl-2-phenyl imidazole. This may be illustrated, but is not limited thereto,

The content of the curing agent may be selected according to the composition of the composition, for example, the type or ratio of the base resin. For example, the curing agent may be included in an amount of 1 to 20 parts by weight, 1 to 10 parts by weight, or 1 to 5 parts by weight based on 100 parts by weight of the base resin. However, the weight ratio may be changed according to the type and ratio of the functional group of the base resin or the compound, or the crosslinking density to be implemented.

In one example, when the reactive functional group is a functional group that can be cured by irradiation of active energy rays, as the initiator, for example, a cationic photopolymerization initiator may be used.

As the cationic photopolymerization initiator, an onium salt or an organometallic salt based ionized cationic initiator or an organosilane or latent sulfonic acid based or non-ionized cationic photopolymerization initiator may be used. Examples of the onium salt-based initiator include a diaryliodonium salt, a triarylsulfonium salt, or an aryldiazonium salt. Initiation of an organometallic salt series Examples of zero may be iron arene, and the like, and examples of the organosilane-based initiator include o-nitrobenzyl triaryl silyl ether, triaryl silyl peroxide. Alternatively, acyl silane may be exemplified, and the latent sulfuric acid-based initiator may include α-sulfonyloxy ketone or α-hydroxymethylbenzoin sulfonate, but is not limited thereto. .

In one example, as the cationic initiator, an ionized cationic photopolymerization initiator may be used.

In one example, the initiator may be included in an amount of 0.1 to 10 parts by weight, 0.1 to 7 parts by weight, or 0.1 to 6 parts by weight, based on 100 parts by weight of the base resin.

In the present specification, unless otherwise specified, the unit "parts by weight" means a weight ratio between each component.

In addition to the above-described configuration, the pressure-sensitive adhesive composition according to the present application may include various additives according to the use, the type of the resin component, and the manufacturing process of the pressure-sensitive adhesive to be described later within a range that does not affect the effects of the above-described invention. For example, the pressure-sensitive adhesive composition may include a moisture adsorbent, an inorganic filler, a coupling agent, a crosslinking agent, a curable material, an ultraviolet stabilizer, or an antioxidant in an appropriate range according to the desired physical properties.

In addition, the pressure-sensitive adhesive composition according to the present application may have a gel content of 40% or more according to General Formula 3 below.

[General Formula 3]

Gel content (% by weight) = B/A × 100

In the general formula 3, A represents the mass of the pressure-sensitive adhesive composition, and B is the pressure-sensitive adhesive composition is immersed in toluene at 25° C. for 24 hours and then filtered through a 200 mesh (pore size 74 μm) network, and does not pass through the network. It shows the dry mass of the insoluble part of an adhesive composition.

The gel content represented by the general formula 3 may be 40% to 95%, 45% to 90%, or 50 to 85%. That is, the present invention can provide an adhesive having an excellent crosslinking structure and degree of crosslinking by controlling the gel content within the above range.

The present application relates to an adhesive film including an adhesive layer. In addition, the present application relates to a protective film including an adhesive layer. The film may include a base layer and an adhesive layer formed on one surface of the base layer. The pressure-sensitive adhesive layer may include a base resin containing an olefin-based compound as a polymerized unit and having a reactive functional group derived from an unsaturated group of 20 to 90 mol%. In addition, the pressure-sensitive adhesive layer may have an adhesion (measurement temperature: 23° C., peel rate: 300 mm/min, peel angle: 180°) to an alkali-free glass after curing of 20 gf/in or less.

The structure of the film of the present application is not particularly limited, but as an example, a base layer or a release film (hereinafter sometimes referred to as a "first film"); And it may have a structure including the pressure-sensitive adhesive layer formed on the base layer or the release film.

The film of the present application may further include a base layer or a release film (hereinafter, referred to as “second film”) formed on the pressure-sensitive adhesive layer.

The specific type of the first film that can be used in the present application is not particularly limited. In the present application, as the first film, for example, a general polymer film in this field may be used. In the present application, for example, as the substrate or release film, a polyethylene terephthalate film, a polytetrafluoroethylene film, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a vinyl chloride copolymer film, a polyurethane film , An ethylene-vinyl acetate film, an ethylene-propylene copolymer film, an ethylene-ethyl acrylate copolymer film, an ethylene-methyl acrylate copolymer film, or a polyimide film may be used. In addition, an appropriate release treatment may be performed on one or both sides of the base layer or release film of the present application. Examples of the release agent used in the release treatment of the substrate layer may be alkyd-based, silicone-based, fluorine-based, unsaturated ester-based, polyolefin-based or wax-based, among which alkyd-based, silicone-based, or fluorine-based release agents are used in terms of heat resistance. Although preferred, it is not limited thereto.

In addition, the type of the second film (hereinafter, referred to as “cover film” in some cases) that can be used in the present application is not particularly limited. For example, in the present application, as the second film, within the range exemplified in the above-described first film, the same or different types as the first film may be used. In addition, in the present application, an appropriate release treatment may also be performed on the second film and used.

The thickness of the pressure-sensitive adhesive layer included in the film of the present application is not particularly limited, and may be appropriately selected according to the following conditions in consideration of the application to which the film is applied. The thickness of the pressure-sensitive adhesive layer included in the film of the present application may be about 5 µm to 200 µm, preferably about 10 µm to 150 µm.

In addition, the film may have excellent light transmittance in the visible light region. In one example, the film of the present application may exhibit a light transmittance of 80% or more with respect to the visible light region. For example, the film may have a light transmittance of 85% or more or 90% or more with respect to the visible light region. In addition, the film of the present application may exhibit excellent light transmittance and low haze. In one example, the film may exhibit a haze of 10% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, or 3% or less. The optical properties may be measured at 550 nm using a UV-Vis Spectrometer.

The present application also relates to a method of manufacturing the pressure-sensitive adhesive composition described above. In one example, the manufacturing method may include modifying the base resin of the pressure-sensitive adhesive composition. The modifying step may be a step of introducing a reactive functional group by epoxidating the unsaturated group of the base resin. Specifically, the epoxidation may be performed using the aforementioned, oxidizing agent.

In one example, the base resin may satisfy the following General Formula 2.

[General Formula 2]

X ≥ pH 5

In General Formula 2, X represents a pH measured at 83° C. of a mixture containing 100 parts by weight of purified water having a pH of 6.04 at 83° C. and 10 parts by weight of the base resin based on 100 parts by weight of the purified water.

In the present application, by controlling the pH of the base resin to 5 or more during the reforming step, side reactions due to high acidity can be suppressed. That is, when the pH of the base resin is less than 5 during the reforming step, side reactions may occur due to high acidity, and a large amount of hydroxyl groups may be formed. In addition, after the reforming step, since a separate washing or purification process is required to neutralize high acidity, considering cost and productivity, it may not be suitable for mass production.

The present application provides a pressure-sensitive adhesive composition having excellent durability and excellent optical properties while implementing a high crosslinking density by functionalizing an unsaturated group in a rubber-based resin, and a protective film including the same.

Hereinafter, the present invention will be described in more detail through examples according to the present invention and comparative examples not according to the present invention, but the scope of the present invention is not limited by the examples presented below.

Manufacturing example One

100 parts by weight of toluene and 15 parts by weight of rubber-based resin styrene-isoprene-styrene (SIS, Quintac3421, Zeon Chemical, 86% unsaturated group) were added to a sealed 500 mL reaction vessel, and stirred at room temperature until the resin was dissolved. In addition, 15 parts by weight of acetone, 8 parts by weight of sodium bicarbonate dissolved in water, and 15 parts by weight of potassium peroxomonosulfate were added to the reaction vessel, and the reaction was carried out by stirring at room temperature for about 20 hours. Thereafter, separation was performed using the difference in density between the solvent toluene and water, and a modified base resin P1 was obtained (resin solid content was 23%, epoxy conversion rate was 87%).

In the above, the epoxy conversion rate is measured through NMR spectrum analysis (500MHz, 1H NMR, Bruker). The sample was dissolved in a CDCl ₃ (w/0.03% TMS) solvent to measure the NMR spectrum, and the relative molar ratio for each structure was calculated based on the peak integral value to calculate the conversion rate from unsaturated group (double bond) to epoxide.

Manufacturing example 2

Instead of styrene-isoprene-styrene, isobutyl isoprene rubber (IIR, Butyl365, Exxon Mobil, unsaturated group 2.3%) was added to the base resin in the same manner as in Preparation Example 1 to obtain a base resin P2 ( Resin solid content is 16%, epoxy conversion is 99%.).

Manufacturing example 3

A modification reaction was carried out in the same manner as in Preparation Example 1, except that 3 parts by weight of the oxone content was added, and a modified resin P3 was obtained (resin solid content was 21%, epoxy conversion rate was 34%).

Example One

100 g of the obtained base resin P1 was put into a mixing container, and a terpene phenolic tackifier (DERTOPHENE T 115, DRT) was added to the container in an amount of 40 parts by weight based on 100 parts by weight of the solid content of the base resin. An additional 1 part by weight of a non-antimony photoinitiator (CPI-200K, San-Apro Ltd.) was added to the container based on 100 parts by weight of the solid content of the base resin. Then, toluene was added so that the total solid content was 20% to prepare a coating solution.

A uniform pressure-sensitive adhesive composition solution (solvent: toluene) was prepared using a conventional mechanical stirrer as the mixing container.

The prepared solution was applied to the release surface of the release PET and dried in an oven at 130° C. for 3 minutes (5 atm) to prepare a protective film including an adhesive layer having a thickness of 50 μm. The physical properties of the sample obtained by irradiating the prepared film with ultraviolet rays of 2 J/cm ² under a nitrogen atmosphere (100 mW/cm ² based on area A) were measured.

Example 2

A protective film was prepared in the same manner as in Example 1, except that no tackifier was added.

Comparative example One

A protective film was prepared in the same manner as in Example 2, except that P2 according to Preparation Example 2 was added instead of P1 as the base resin.

Comparative example 2

100 parts by weight of styrene-isoprene-styrene (SIS, Quintac3421, Zeon Chemical) as a base resin and tricyclodecane dimethanol diacrylate (Miramer M262, Miwon) as a curable compound were added in 2 parts by weight based on 100 parts by weight of the base resin And, a protective film was prepared in the same manner as in Example 2, except that 0.5 parts by weight of a photoinitiator (Irgacure 651) was added to 100 parts by weight of the base resin.

Comparative example 3

A protective film was prepared in the same manner as in Example 1, except that P3 according to Preparation Example 3 was added instead of P1 as the base resin.

Physical properties were measured as follows for the base resin, pressure-sensitive adhesive composition, and protective film prepared in Examples and Comparative Examples.

One. Gel content

Gel content (% by weight) = B/A × 100

In the above, A represents the mass of the pressure-sensitive adhesive composition, B is the pressure-sensitive adhesive composition is immersed in toluene at 25° C. for 24 hours and then filtered through a 200 mesh (pore size 74 μm) net, and the pressure-sensitive adhesive composition that does not pass through the net It represents the dry mass of the insoluble matter of.

2. Adhesion

A specimen was prepared by cutting the adhesive prepared in Examples and Comparative Examples into 2.5cm x 10cm (width x length), and one side of the specimen was attached to a glass (alkali-free glass), respectively, at room temperature (23°C). At the elapsed time, the adhesion was measured at a peel rate of 300 mm/min and a peel angle of 180 degrees.

3. Residue

A protective film (PET/adhesive) was attached to the glass surface and kept in an oven at 80° C. for 3 days, and when the protective film was peeled off, the presence or absence of the adhesive layer was observed to confirm the occurrence of residue.

Example Comparative example One 2 One 2 3 Gel
(%) 71 86 35 2 41 Adhesion
(gf/in) 12 5 125 25 142 No residue none none none Occur Occur

Claims (16)

A base resin containing an olefinic compound as a polymerization unit and having a reactive functional group derived from an unsaturated group of 20 to 90 mol%, a curing agent or initiator, and a tackifier which is a terpene phenolic resin,
When prepared as a film, the adhesion to alkali-free glass after curing (measurement temperature: 23°C, peeling speed: 300mm/min, peeling angle: 180°) is 20gf/in or less,
The conversion rate of the unsaturated group to the reactive functional group is 70%,
A pressure-sensitive adhesive composition having a gel content of 40% or more according to the following general formula 3:
[General Formula 3]
Gel content (% by weight) = B/A × 100
In the general formula 3, A represents the mass of the pressure-sensitive adhesive composition, and B is the pressure-sensitive adhesive composition is immersed in toluene at 25° C. for 24 hours and then filtered through a 200 mesh (pore size 74 μm) network, and does not pass through the network. It shows the dry mass of the insoluble part of an adhesive composition. delete The pressure-sensitive adhesive composition of claim 1, wherein the base resin has a hydroxyl group area ratio (integration ratio, R) of 10% or less represented by the following General Formula 1:
[General Formula 1]
R = H/(E+H)×100
In the general formula 1, E represents the area (integration) of the peak resulting from the reactive functional group in ¹ H-NMR, and H represents the area of the peak resulting from the hydroxyl group (integration). The pressure-sensitive adhesive composition of claim 1, wherein the base resin has an epoxy equivalent weight of 100 g/eq to 20,000 g/eq. The pressure-sensitive adhesive composition of claim 1, wherein the base resin has a number average molecular weight in the range of 100,000 to 1,000,000. The pressure-sensitive adhesive composition according to claim 1, which does not contain a curable compound. The pressure-sensitive adhesive composition according to claim 6, wherein the curable compound is an epoxy compound or a polyfunctional acrylate. delete delete The pressure-sensitive adhesive composition of claim 1, wherein the tackifier is included in an amount of 10 to 50 parts by weight based on 100 parts by weight of the base resin. delete Base layer; And as a pressure-sensitive adhesive layer formed on one surface of the base layer, comprising a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition according to claim 1,
The pressure-sensitive adhesive layer is a protective film having an adhesion (measurement temperature: 23°C, peeling speed: 300mm/min, peeling angle: 180°) to an alkali-free glass after curing of 20gf/in or less. The protective film according to claim 12, which exhibits a haze of 10% or less. The protective film according to claim 12, which exhibits a light transmittance of 80% or more with respect to the visible light region. The method of claim 12, wherein the base layer is polyethylene terephthalate, polytetrafluoroethylene, polyethylene, polypropylene, polybutene, polybutadiene, vinyl chloride copolymer, polyurethane, ethylene-vinyl acetate, ethylene-propylene copolymer, ethylene- A protective film comprising an ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, or a polyimide. The protective film according to claim 12, wherein a conversion ratio of an unsaturated group to the reactive functional group is 70% or more.