Adhesive composition and adhesive film comprising same

Abstract

The present invention relates to an adhesive composition and an adhesive film comprising same and, specifically, to an adhesive composition and an adhesive film comprising same, the adhesive composition comprising an acrylate-based prepolymer and an acrylate-based polymer, wherein the acrylate-based polymer is contained in an amount of 2 parts by weight (exclusive) to 15 parts by weight (exclusive) relative to 100 parts by weight of the acrylate-based prepolymer.

Description

Adhesive composition and adhesive film comprising the same

[0001] This invention claims the benefit of patent application No. 10-2024-0055141 filed with the Korean Intellectual Property Office on April 25, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an adhesive composition and an adhesive film comprising the same, and more particularly, to an adhesive composition comprising an acrylate-based prepolymer and an acrylate-based polymer, wherein the acrylate-based polymer is contained in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate-based prepolymer, and an adhesive film comprising the same.

[0003] A typical display device may include a polarizing plate, a phase shifter, and other functional layers made of plate-like materials. These are attached to an adhesive within the display device via an adhesive, and can be manufactured in various shapes, such as bendable or foldable.

[0004] Recently, display devices, such as mobile display devices, are being developed into various types of devices that are thinner, lighter, and more energy-efficient, such as foldable or rollable devices, in line with the deepening, popularization, and popularization of informatization.

[0005] In the case of optical elements and films applied to the above devices, stress is generated by external bending or flexing during use. These devices cannot utilize commonly used optical elements or films as is, and it is required to reduce the stress generated during bending or flexing.

[0006] In addition, the adhesive composition that secures the above devices must adhere well when subjected to repeated stress, such as with the devices. If it does not adhere well, it may cause bubbles or defects.

[0007] Accordingly, there was a need to develop an adhesive composition that is suitable for foldable mechanical devices, has high peel strength, low elastic modulus at low temperatures, and does not cause defects such as lifting or bubbles during folding tests.

[0008] The technical problem to be achieved by the present invention is to provide an adhesive composition having high peel strength suitable for a foldable mechanical device, low elastic modulus at low temperatures, and not causing defects such as lifting or bubbles during a folding test.

[0009] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0010] One embodiment of the present invention provides an adhesive composition comprising an acrylate-based prepolymer and an acrylate-based polymer, wherein the acrylate-based polymer is contained in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate-based prepolymer.

[0011] According to one embodiment of the present invention, the weight average molecular weight (Mw) of the acrylate prepolymer may be 500,000 or more and 3,000,000 or less.

[0012] According to one embodiment of the present invention, the weight average molecular weight (Mw) of the acrylate polymer may be 3,000 or more and 10,000 or less.

[0013] According to one embodiment of the present invention, the glass transition temperature (Tg) of the acrylate polymer may be 90°C or more and 200°C or less.

[0014] According to one embodiment of the present invention, the adhesive composition may include one selected from the group consisting of a multifunctional crosslinking agent, a photoinitiator, a coupling agent, and a combination thereof.

[0015] According to one embodiment of the present invention, the adhesive composition may further include a multifunctional crosslinking agent, a photoinitiator, and a coupling agent.

[0016] One embodiment of the present invention provides an adhesive film comprising a substrate layer; and an adhesive layer; wherein the adhesive layer comprises an acrylate-based prepolymer and an acrylate-based polymer.

[0017] According to one embodiment of the present invention, the acrylate polymer may be included in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate prepolymer.

[0018] According to one embodiment of the present invention, the peeling force of the adhesive film for the substrate may be 800 gf / inch or more and 1,300 gf / inch or less.

[0019] According to one embodiment of the present invention, the haze of the adhesive layer may be less than 1.2%.

[0020] According to one embodiment of the present invention, the storage elastic modulus value of the adhesive layer at -20°C is 10 5 It may be less than Pa.

[0021] An adhesive composition according to one embodiment of the present invention can exhibit higher substrate peeling strength than before, satisfy folding tests and chemical resistance, and suppress defects such as lifting and bubble generation by adjusting the content of an acrylate-based prepolymer and an acrylate-based polymer to an appropriate level.

[0022] An adhesive film according to one embodiment of the present invention has a low elastic modulus at low temperatures and exhibits high substrate peeling strength, satisfies folding tests and chemical resistance, and can suppress defective phenomena such as lifting and bubble generation.

[0023] In this specification, when a part is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0024] In this specification, “A and / or B” means “A and B, or A or B.”

[0025] In this specification, when it is said that a component is “on”, this does not exclude other components being placed therebetween, unless otherwise specifically stated, but rather means that other components may be placed thereon.

[0026] Hereinafter, the present invention will be described in more detail.

[0027] One embodiment of the present invention includes an adhesive composition comprising an acrylate-based prepolymer and an acrylate-based polymer, and wherein the acrylate-based polymer is contained in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate-based prepolymer.

[0028] An adhesive composition according to one embodiment of the present invention can exhibit higher substrate peeling strength than before by adjusting the content of an acrylate-based prepolymer and an acrylate-based polymer to an appropriate level, thereby satisfying a folding test and chemical resistance, and suppressing defects such as lifting and bubble generation.

[0029] According to one embodiment of the present invention, the adhesive composition includes an acrylate-based prepolymer and an acrylate-based polymer.

[0030] According to one embodiment of the present invention, the acrylate prepolymer may be a partially polymerized form of acrylate monomer components.

[0031] According to one embodiment of the present invention, the acrylate polymer may be a copolymer of acrylate monomer components. “(Meth)acrylic” means acrylic and / or methacrylic.

[0032] According to one embodiment of the present invention, the acrylate monomer is, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, n-hexyl (meth)acrylate, heptyl (meth)acrylate, ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, Examples thereof include dodecyl (meth)acrylate (i.e., lauryl (meth)acrylate), isotridecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, and nonadecyl (meth)acrylate.

[0033] According to one embodiment of the present invention, the acrylate monomer may include, for example, (meth)acrylic acid cycloalkyl esters, (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring, and (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings. Examples of the (meth)acrylic acid cycloalkyl esters include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate. Examples of the (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring include isobornyl (meth)acrylate.

[0034] According to one embodiment of the present invention, the acrylate monomer, as a hydroxyl group-containing monomer, may include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

[0035] According to one embodiment of the present invention, the acrylate-based prepolymer may be a partial polymerization of the above-mentioned acrylate-based monomers. Preferably, the acrylate-based monomer may be at least one selected from the group consisting of 2-ethylhexylacrylate (2-EHA), 4-hydroxybutylacrylate (4-HBA), isobornyl acrylate (IBoA), 2-hydroxyethyl acrylate (HEA), butyl acrylate (BA), cyclohexyl acrylate (CHA), and combinations thereof. More preferably, the acrylate-based monomer may be at least one selected from the group consisting of 2-ethylhexylacrylate (2-EHA), 4-hydroxybutylacrylate (4-HBA), and combinations thereof. By selecting the acrylate-based monomer from the above, a partial polymerization may be performed to produce an adhesive composition having excellent physical properties.

[0036] According to one embodiment of the present invention, the acrylate polymer may be a copolymer of the above-mentioned acrylate monomers. Preferably, the acrylate monomer may be at least one selected from the group consisting of ethyl acetate (EAc), isobornyl acrylate (IBOA), dicyclopentanyl methacrylate (DCPMA), methyl methacrylate (MMA), ethylhexyl acrylate (EHA), isobornyl acrylate (IBoA), 2-hydroxy ethyl acrylate (HEA), butyl acrylate (BA), cyclohexyl acrylate (CHA), 4-hydroxy butyl acrylate (HBA), and combinations thereof. More preferably, the acrylate monomer may be at least one selected from the group consisting of ethyl acetate (EAc), isobornyl acrylate (IBOA), dicyclopentanyl methacrylate (DCPMA), methyl methacrylate (MMA), and combinations thereof. By selecting the acrylate monomer from the above-described monomers, an adhesive composition having excellent physical properties can be manufactured by polymerization.

[0037] According to one embodiment of the present invention, the acrylate polymer is included in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate prepolymer. Specifically, the acrylate polymer may be included in an amount of 3 parts by weight or more and 14 parts by weight or less, 5 parts by weight or more and 13 parts by weight or less, 5 parts by weight or more and 12 parts by weight or less, 5 parts by weight or more and 11 parts by weight or less, or 5 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the acrylate prepolymer. As described above, by controlling the weight part of the acrylate polymer based on 100 parts by weight of the acrylate prepolymer, a higher substrate peeling force can be exhibited than before, thereby satisfying the folding test and chemical resistance, and suppressing defective phenomena such as lifting and bubble generation.

[0038] According to one embodiment of the present invention, the weight average molecular weight (Mw) of the acrylate-based prepolymer may be 500,000 or more and 3,000,000 or less. Specifically, the weight average molecular weight (Mw) of the acrylate-based prepolymer may be 600,000 or more and 2,800,000 or less, 700,000 or more and 2,600,000 or less, 800,000 or more and 2,400,000 or less, 900,000 or more and 2,200,000 or less, 1,000,000 or more and 1,800,000 or less, 1,000,000 or more and 1,600,000 or less, 1,000,000 or more and 1,400,000 or less, 1,000,000 or more and 1,200,000 or less, or 1,050,000 or more and 1,150,000 or less. By controlling the weight average molecular weight (Mw) of the acrylate-based prepolymer within the above-described range, an adhesive composition having excellent physical properties can be prepared.

[0039] According to one embodiment of the present invention, the weight average molecular weight (Mw) of the acrylate polymer may be 3,000 or more and 10,000 or less. Specifically, the weight average molecular weight (Mw) of the acrylate polymer may be 3,100 or more and 9,000 or less, 3,200 or more and 8,000 or less, 3,300 or more and 7,000 or less, 3,400 or more and 6,000 or less, 3,500 or more and 5,500 or less, 3,600 or more and 5,400 or less, 3,700 or more and 5,300 or less, 3,800 or more and 5,200 or less, 3,900 or more and 5,100 or less, or 4,000 or more and 5,000 or less. By controlling the weight average molecular weight (Mw) of the acrylate polymer within the above-described range, an adhesive composition having excellent physical properties can be manufactured.

[0040] According to one embodiment of the present invention, the glass transition temperature (Tg) of the acrylate polymer may be 90° C. or more and 200° C. or less. Specifically, the glass transition temperature (Tg) of the acrylate polymer may be 95° C. or more and 195° C. or less, 95° C. or more and 190° C. or less, 95° C. or more and 185° C. or less, 95° C. or more and 180° C. or less, 95° C. or more and 175° C. or less, or 100° C. or more and 175° C. By controlling the glass transition temperature (Tg) of the acrylate polymer within the above-described range, an adhesive composition having excellent physical properties can be prepared.

[0041] According to one embodiment of the present invention, the adhesive composition may include one selected from the group consisting of a multifunctional crosslinking agent, a photoinitiator, a coupling agent, and a combination thereof.

[0042] According to one embodiment of the present invention, the adhesive composition may further comprise a multifunctional crosslinking agent. By further comprising the multifunctional crosslinking agent, the adhesive composition prepared by crosslinking an acrylate prepolymer and an acrylate polymer exhibits higher substrate peel strength than before, satisfies folding tests and chemical resistance, and suppresses defects such as lifting and bubble generation. Examples of the multifunctional crosslinking agent include multifunctional (meth)acrylates. For example, ester compounds of polyhydric alcohols and (meth)acrylic acid, such as (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate; allyl(meth)acrylate; vinyl(meth)acrylate; divinylbenzene; epoxy acrylate; Polyester acrylate; urethane acrylate; butyl di(meth)acrylate; hexyl di(meth)acrylate; Preferably, the polyfunctional crosslinking agent may be hexanediol diacrylate (HDDA).

[0043] According to one embodiment of the present invention, the multifunctional crosslinking agent may be included in an amount of 0.05 parts by weight or more and 0.5 parts by weight or less based on 100 parts by weight of the acrylate-based prepolymer. Specifically, the multifunctional crosslinking agent may be included in an amount of 0.1 parts by weight or more and 0.45 parts by weight or less, 0.11 parts by weight or more and 0.4 parts by weight or less, 0.12 parts by weight or more and 0.35 parts by weight or less, 0.13 parts by weight or more and 0.3 parts by weight or less, 0.14 parts by weight or more and 0.25 parts by weight or less, 0.14 parts by weight or more and 0.2 parts by weight or less, 0.14 parts by weight or more and 0.18 parts by weight or less, or 0.14 parts by weight or more and 0.16 parts by weight or less based on 100 parts by weight of the acrylate-based prepolymer, and preferably may be included in an amount of 0.15 parts by weight. By controlling the range of the multifunctional crosslinking agent within the above-described range, the pressure-sensitive adhesive composition manufactured can exhibit higher substrate peel strength than before, satisfy folding tests and chemical resistance, and suppress defects such as lifting and bubble generation.

[0044] According to one embodiment of the present invention, the adhesive composition may further include a photoinitiator. Any photoinitiator that can initiate a polymerization reaction of the adhesive composition through light irradiation or the like may be used. For example, alpha-hydroxyketone compounds (e.g., IRGACURE 184, IRGACURE 500, IRGACURE 2959, DAROCUR 1173; Ciba Specialty Chemicals); phenylglyoxylate compounds (e.g., IRGACURE 754, DAROCUR MBF; Ciba Specialty Chemicals); benzyldimethyl ketal compounds (e.g., IRGACURE 651; Ciba Specialty Chemicals); a-aminoketone compounds (e.g., IRGACURE 369, IRGACURE 907, IRGACURE 1300; Ciba Specialty Chemicals); Monoacylphosphine compounds (MAPO) (ex. DAROCUR TPO; Ciba Specialty Chemicals); Bisacylphosphene compounds (BAPO) (ex. IRGACURE 819, IRGACURE 819DW; Ciba Specialty Chemicals); Phosphine oxide compounds (ex. IRGACURE 2100; Ciba Specialty Chemicals); Metallocene compounds (ex. IRGACURE 784; Ciba Specialty Chemicals); Iodonium salts (ex. IRGACURE 250; Ciba Specialty Chemicals); and mixtures of one or more of the above (ex.Examples thereof include DAROCUR 4265, IRGACURE 2022, IRGACURE 1300, IRGACURE 2005, IRGACURE 2010, IRGACURE 2020; Ciba Specialty Chemicals (manufactured by Ciba), and one or more of the above may be used, but is not limited thereto.

[0045] According to one embodiment of the present invention, the photoinitiator may be included in an amount of 0.1 part by weight or more and 0.8 part by weight or less based on 100 parts by weight of the acrylate-based prepolymer. Specifically, the photoinitiator may be included in an amount of 0.12 part by weight or more and 0.7 part by weight or less, 0.14 part by weight or more and 0.6 part by weight or less, 0.16 part by weight or more and 0.5 part by weight or less, 0.18 part by weight or more and 0.4 part by weight or less, 0.2 part by weight or more and 0.35 part by weight or less, 0.22 part by weight or more and 0.3 part by weight or less, or 0.24 part by weight or more and 0.26 part by weight or less based on 100 parts by weight of the acrylate-based prepolymer, and preferably 0.25 part by weight. By adjusting the weight portion of the photoinitiator within the above-described range, the polymerization reaction of the adhesive composition can be initiated, thereby exhibiting a higher substrate peeling strength than before, satisfying the folding test and chemical resistance, and suppressing defects such as lifting and bubble generation.

[0046] According to one embodiment of the present invention, the adhesive composition may further include a coupling agent. The coupling agent can improve the adhesiveness and adhesive stability of the adhesive, thereby improving heat resistance and moisture resistance, and also enhancing adhesive reliability even when left for a long period of time under harsh conditions. The coupling agent may be, for example, gamma-glycidoxypropyl triethoxy silane, gamma-glycidoxypropyl trimethoxy silane, gamma-glycidoxypropyl methyldiethoxy silane, gamma-glycidoxypropyl triethoxy silane, 3-mercaptopropyl trimethoxy silane, vinyltrimethoxysilane, vinyltriethoxy silane, gamma-methacryloxypropyl trimethoxy silane, gamma-methacryloxy propyl triethoxy silane, gamma-aminopropyl trimethoxy silane, gamma-aminopropyl triethoxy silane, 3-isocyanatopropyl triethoxy silane, gamma-acetoacetatepropyl trimethoxysilane, gamma-acetoacetatepropyl triethoxy silane, beta-cyanoacetyl trimethoxy silane, beta-cyanoacetyl triethoxy silane, Acetoxyacetotrimethoxysilane, etc. can be used, and one or a mixture of two or more of the above can be used. It is preferable to use a silane coupling agent having an acetoacetate group or a beta-cyanoacetyl group, but the present invention is not limited thereto.

[0047] According to one embodiment of the present invention, the coupling agent may be included in an amount of 0.05 parts by weight or more and 0.5 parts by weight or less, preferably 0.1 parts by weight or more and 0.3 parts by weight or less, and more preferably 0.2 parts by weight, based on 100 parts by weight of the acrylate-based prepolymer. By adjusting the weight of the coupling agent within the above-described range, the adhesiveness and adhesive stability of the adhesive can be improved, thereby improving the adhesive reliability.

[0048] According to one embodiment of the present invention, the adhesive composition may further comprise a multifunctional crosslinking agent, a photoinitiator, and a coupling agent. As described above, by further comprising a multifunctional crosslinking agent, a photoinitiator, and a coupling agent, the adhesive composition exhibits higher substrate peeling strength than before, satisfies folding tests and chemical resistance, and suppresses defects such as lifting and bubble generation.

[0049] According to one embodiment of the present invention, the adhesive layer comprises a substrate layer; and an adhesive layer; wherein the adhesive layer comprises an adhesive film including an acrylate-based prepolymer and an acrylate-based polymer.

[0050] An adhesive film according to one embodiment of the present invention has a low elastic modulus at low temperatures and exhibits high substrate peeling strength, satisfies folding tests and chemical resistance, and can suppress defective phenomena such as lifting and bubble generation.

[0051] According to one embodiment of the present invention, the substrate layer may be a resin film. Specifically, it may include a plastic material such as a polyester series such as polyethylene terephthalate (PET), a polycarbonate series, a polyolefin series, a polyimide series, etc.

[0052] According to one embodiment of the present invention, the acrylate polymer may be included in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate prepolymer.

[0053] According to one embodiment of the present invention, the contents of the acrylate-based prepolymer and the acrylate-based polymer are as described above.

[0054] According to one embodiment of the present invention, the peeling force of the adhesive film with respect to the substrate may be 800 gf / inch or more and 1,300 gf / inch or less. Specifically, the peeling force of the adhesive film with respect to the substrate may be 810 gf / inch or more and 1,271 gf / inch or less, 820 gf / inch or more and 1,270 gf / inch or less, 830 gf / inch or more and 1,269 gf / inch or less, 840 gf / inch or more and 1,268 gf / inch or less, 850 gf / inch or more and 1,267 gf / inch or less, 860 gf / inch or more and 1,266 gf / inch or less, or 868 gf / inch or more and 1,266 gf / inch or less. By controlling the peeling force of the adhesive film with respect to the substrate within the above-described range, durability can be improved.

[0055] According to one embodiment of the present invention, the haze of the adhesive layer may be less than 1.2%. Specifically, the haze of the adhesive layer may be 0.48% or more and 1.1% or less, 0.49% or more and 1.0% or less, 0.49% or more and 0.9% or less, or 0.49% or more and 0.81% or less. By controlling the haze of the adhesive layer within the above-described range, the optical properties can be improved.

[0056] According to one embodiment of the present invention, the storage elastic modulus value of the adhesive layer at -20°C is 10 5 It may be less than Pa. Specifically, the storage elastic modulus value of the adhesive layer at -20 ℃ is 9 X 10 4 Pa or more 10 5 It can be 90,500 Pa or less, 90,500 Pa or more but 99,000 Pa or less, 90,600 Pa or more but 98,000 Pa or less, 90,700 Pa or more but 97,000 Pa or less, 90,800 Pa or more but 96,000 Pa or more, or 90,842 Pa or more but 95,454 Pa or less.

[0057] Hereinafter, the present invention will be described in detail using examples. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention is not limited to the examples described below. The examples in this specification are provided to more fully explain the present invention to those of ordinary skill in the art.

[0058]

[0059] <Manufacturing Example>

[0060] Synthesis Example 1: Acrylate Prepolymer (A)

[0061] 80 parts by weight of 2-ethylhexyl acrylate (2-EHA), 20 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.05 parts by weight of a photopolymerization initiator (trade name: Igacure 184), and 0.015 parts by weight of a molecular weight regulator dodecyl mercaptan are charged into a polymerization reactor. Then, nitrogen is added and stirring is performed for 20 minutes. After 20 minutes, partial polymerization is performed by exposing to ultraviolet rays to obtain an acrylate prepolymer (A, 100 parts by weight) having a molecular weight (Mw) of 1.1 million.

[0062]

[0063] Synthesis Example 2: Acrylate polymer (B)

[0064] 100 parts by weight of ethyl acetate (EAc), 100 parts by weight of isobornyl acrylate (IBOA), and 7 parts by weight of dodecyl mercaptan as a molecular weight regulator are charged into a polymerization reactor. Then, nitrogen is introduced and stirring is performed at 70°C for 40 minutes. After 40 minutes, the internal temperature of the polymerization reactor is set to maintain 70°C, and 0.2 parts by weight of V-65 (2,2'-Azobis(2,4-dimethylvaleronitrile)) is introduced as a thermal polymerization initiator to perform polymerization. 2 hours after the first initiator is introduced, an additional 0.2 parts by weight of a thermal polymerization initiator is introduced. The reaction is terminated 5 hours after the second initiator is introduced. The completed polymerization resin is placed in a 120°C oven to volatilize the residual monomer and additives, thereby obtaining a solid acrylate polymer (B) having a molecular weight (Mw) of 5,000. At this time, the glass transition temperature is 100 ℃.

[0065]

[0066] Synthesis Example 3: Acrylate polymer (C)

[0067] 100 parts by weight of ethyl acetate (EAc), 100 parts by weight of dicyclopentanyl methacrylate (DCPMA), and 7 parts by weight of dodecyl mercaptan as a molecular weight regulator are added to a polymerization reactor. Then, nitrogen is added and stirring is performed at 70°C for 40 minutes. After 40 minutes, the internal temperature of the polymerization reactor is set to maintain 70°C, and 0.2 parts by weight of V-65 (2,2'-Azobis(2,4-dimethylvaleronitrile)) is added as a thermal polymerization initiator to proceed with polymerization. 2 hours after adding the first initiator, 0.2 parts by weight of a thermal polymerization initiator is additionally added. The reaction is terminated 5 hours after adding the second initiator. The completed polymerization resin is placed in a 120°C oven to volatilize the residual monomer and additives, thereby obtaining a solid acrylate polymer (C) having a molecular weight (Mw) of 4,500. At this time, the glass transition temperature is 175°C.

[0068]

[0069] Synthesis Example 4: Acrylate polymer (D)

[0070] 100 parts by weight of ethyl acetate (EAc), 60 parts by weight of dicyclopentanyl methacrylate (DCPMA), 40 parts by weight of methyl methacrylate (MMA), and 7 parts by weight of dodecyl mercaptan as a molecular weight regulator are charged into a polymerization reactor. Then, nitrogen is added and stirring is performed at 70°C for 40 minutes. After 40 minutes, the internal temperature of the polymerization reactor is set to maintain 70°C, and 0.2 parts by weight of V-65 (2,2'-Azobis(2,4-dimethylvaleronitrile)) is added as a thermal polymerization initiator to proceed with polymerization. 2 hours after the first initiator is added, 0.2 parts by weight of a thermal polymerization initiator is additionally added. The reaction is terminated 5 hours after the second initiator is added. The completed polymerization resin is placed in a 120°C oven to volatilize the residual monomer and additives, thereby obtaining a solid acrylate polymer (D) having a molecular weight (Mw) of 4,000. At this time, the glass transition temperature is 140°C.

[0071]

[0072] <Examples and Comparative Examples>

[0073] Example 1

[0074] An adhesive composition was prepared by mixing 100 parts by weight of the partially polymerized acrylate prepolymer (A) manufactured in Synthesis Example 1 with 0.15 parts by weight of hexanediol diacrylate, a multifunctional crosslinking agent, 0.2 parts by weight of a coupling agent (KBM 403, Shin-Etsu), 0.25 parts by weight of a photoinitiator (Irgacure 651, Ciba Specialty Chemicals), and 5 parts by weight of an acrylate polymer (B).

[0075] Next, the manufactured coating solution was coated on a polyethylene terephthalate film (XD500P, Toray Advanced Materials, thickness: 75 ㎛) that had been subjected to UV curing using a bar coater so that the thickness became 125 ㎛. After that, the film was cured by irradiating it with ultraviolet rays using a UV lamp for 5 minutes, thereby manufacturing an adhesive film.

[0076]

[0077] Examples 2 to 4 and Comparative Examples 1 to 3

[0078] An adhesive film was manufactured in the same manner as in Example 1, except that the composition of the adhesive composition was changed as shown in Table 1 below.

[0079]

[0080] Acrylate prepolymerAcrylate polymer BAcrylate polymer CAcrylate polymer DMultifunctional crosslinkerPhotoinitiatorCoupling agentExample 1A5000.150.250.2Example 2A0500.150.250.2Example 3A0050.150.250.2Example 4A00100.150.250.2Comparative example 1A0000.150.250.2Comparative example 2A2000.150.250.2Comparative example 3A15000.150.250.2

[0081] Unit of content: parts by weight

[0082] Multifunctional crosslinking agent: hexanediol diacrylate (HDDA)

[0083] Coupling agent: KBM 403, Shin-Etsu

[0084] Photoinitiator: Irgacure 651, Ciba Specialty Chemicals

[0085]

[0086] <Experimental Example>

[0087] The physical properties of the adhesive films manufactured in the above examples and comparative examples were measured using the methods presented below.

[0088]

[0089] 1. Measurement of the peeling strength of the substrate

[0090] The adhesive films manufactured in the above examples and comparative examples were cut to a size of 25 mm x 20 cm (width x height), the release film was peeled off, and then attached to stainless steel (SUS 304) by reciprocating a 2 kg roller 5 times. After 20 minutes, the peeling force was measured using a tensile tester under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180°.

[0091]

[0092] 2. Elasticity modulus measurement method

[0093] The adhesive compositions manufactured in the above examples and comparative examples were used to manufacture an adhesive layer having a thickness of about 1 mm. Then, the adhesive between the release films was cut to make a cylindrical specimen measuring 8 mm x 1 mm (=diameter x thickness), and then, using a dynamic rheometer (ARES, RDA, TA Instruments Inc.), the storage modulus at -20°C was measured while applying shear stress between parallel plates at a frequency of 1 Hz.

[0094]

[0095] 3. Optical property measurement

[0096] Transmittance / haze: The manufactured adhesive layer was attached to a 1.1 T glass surface in the form of glass / adhesive layer / glass, and then the haze was measured using NDH 5000 (Nippon Denshoku).

[0097]

[0098] 4. Artificial sebum penetration distance (chemical resistance)

[0099] The adhesive compositions manufactured in the above examples and comparative examples were attached to glass and then cut into pieces measuring 25 mm x 25 mm to manufacture specimens. Thereafter, the specimens were immersed in artificial sebum (ESTASAN 3580, Kosher) for 10 minutes, and the penetration distance of the artificial sebum that penetrated through the side of the specimen, i.e., the adhesive interface between the adhesive and the glass, was measured using a vernier caliper.

[0100] O: Penetration distance of artificial sebum ≤ 0.3 mm,

[0101] △: 0.3mm < penetration distance of artificial sebum ≤ 0.7mm,

[0102] X: 0.7mm < Penetration distance of artificial sebum

[0103]

[0104] 5. Folding Test

[0105] For the folding test, a laminate was manufactured by laminating an adhesive layer between polyimide films of approximately 100 μm on both sides, and cutting the laminate into a rectangular shape with a horizontal length of approximately 8 cm and a vertical length of approximately 18 cm to manufacture a specimen.

[0106] The test was conducted using a folding test facility (Flexigo Co., Ltd. model name: Foldy-100-1C).

[0107] A previously cut specimen was attached to a tester on a unit that can be folded with a curvature radius of 1R and subjected to 200,000 cycles in a chamber that cycles between 25°C and 85°C. After collecting the sample, defects such as the occurrence of bubbles, lifting / peeling, and cracks in the coating layer were visually observed. If any of the above defects occurred, it was evaluated as X, and if none of the above defects occurred, it was evaluated as O.

[0108]

[0109] Base peeling force gf / inch G'(Pa)(-20℃) Haze(%) Artificial sebum Chemical resistance Folding test Example 186890, 8420.49○○ Example 287794, 2670.51○○ Example 391093, 1200.53○○ Example 4126695, 4540.81○○ Comparative example 175081, 5200.47XX Comparative example 276191, 2730.48△X Comparative example 31271182, 8001.2○X

[0110]

[0111] As shown in Table 2 above, the adhesive films manufactured in Examples 1 to 4 according to the present invention contain an acrylate polymer in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of an acrylate prepolymer, so that the peeling force of the adhesive film for the substrate satisfies 800 gf / inch or more and 1,300 gf / inch or less, the haze of the adhesive layer is less than 1.2%, and the storage elastic modulus value of the adhesive layer at -20°C is 10 5 It can be confirmed that it shows higher substrate peeling strength than the existing one while satisfying Pa or less, satisfies folding test and chemical resistance, and does not cause defects such as lifting and bubble generation.

[0112] On the other hand, in the case where the acrylate polymer is not included, as in Comparative Example 1, it can be confirmed that both the folding test and chemical resistance are not satisfied, and defective phenomena such as lifting and bubble generation occur.

[0113] In addition, it can be confirmed that when the weight portion of the acrylate polymer is outside the appropriate range, as in Comparative Examples 2 and 3, the folding test is not satisfied, and defective phenomena such as lifting and bubble generation occur.

[0114] Accordingly, the adhesive composition according to one embodiment of the present invention and the adhesive film including the same specifically include an acrylate-based prepolymer and an acrylate-based polymer, and the acrylate-based polymer is included in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate-based prepolymer, thereby exhibiting high substrate peeling strength, satisfying folding tests and chemical resistance, and suppressing defective phenomena such as lifting and bubble generation.

Claims

1. Contains acrylate prepolymer and acrylate polymer, An adhesive composition, wherein the acrylate polymer is contained in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate prepolymer.

2. In claim 1, An adhesive composition, wherein the weight average molecular weight (Mw) of the above acrylate prepolymer is 500,000 or more and 3,000,000 or less.

3. In claim 1, An adhesive composition, wherein the weight average molecular weight (Mw) of the above acrylate polymer is 3,000 or more and 10,000 or less.

4. In claim 1, An adhesive composition wherein the glass transition temperature (Tg) of the above acrylate polymer is 90°C or more and 200°C or less.

5. In claim 1, An adhesive composition comprising one selected from the group consisting of a multifunctional crosslinking agent, a photoinitiator, a coupling agent, and a combination thereof.

6. In claim 1, An adhesive composition, wherein the adhesive composition further comprises a multifunctional crosslinking agent, a photoinitiator, and a coupling agent.

7. Base layer; and It includes an adhesive layer; The adhesive film, wherein the adhesive layer comprises an acrylate-based prepolymer and an acrylate-based polymer.

8. In claim 7, An adhesive film, wherein the acrylate polymer is contained in an amount of more than 2 parts by weight and less than 15 parts by weight based on 100 parts by weight of the acrylate prepolymer.

9. In claim 7, An adhesive film having a peeling strength for a substrate of the adhesive film of 800 gf / inch or more and 1,300 gf / inch or less.

10. In claim 7, An adhesive film, wherein the haze of the adhesive layer is less than 1.2%.

11. In claim 7, The storage elastic modulus value of the adhesive layer at -20 ℃ is 10 5 Adhesive film having a thickness of less than Pa.