Adhesive composition and adhesive film comprising same

Abstract

The present invention relates to an adhesive composition and an adhesive film comprising same, and more specifically, relates to an adhesive composition and an adhesive film comprising same, the composition comprising a first polymer resin and a second polymer resin and having an elastic modulus of 109 or lower at -20°C and 106 or lower at 20°C.

Description

Adhesive composition and adhesive film comprising the same

[0001] This invention claims the benefit of patent application No. 10-2024-0028705 filed with the Korean Intellectual Property Office on February 28, 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 specifically, to an adhesive composition comprising a first polymer resin and a second polymer resin, and having an elastic modulus value of 10 at -20°C. 9 Below and at 20 ℃, the elastic modulus value is 10 6 The following relates to an adhesive composition and an adhesive film comprising the same.

[0003] OCA (Optically Clear Adhesive) is a material applied to displays and is often used in mobile devices and vehicle displays, for example.

[0004] OCAs applied to vehicles have very different required properties compared to OCAs applied to mobile devices.

[0005] Automotive products have significantly longer replacement cycles than mobile products. Therefore, OCAs used in automotive products must maintain stable properties for a much longer period of time than those used in mobile products.

[0006] Additionally, automotive products are often exposed to much higher temperatures than mobile products, are frequently exposed to external light such as ultraviolet rays, and are frequently exposed to conditions where high and low temperatures alternate with seasonal changes.

[0007] Therefore, OCA applied to automotive products needs to ensure longer-term reliability even under much harsher conditions than in general cases.

[0008] Specifically, high transmittance and low haze (turbidity) are required, along with corrosion resistance. Furthermore, lifting and bubble formation must be minimized to facilitate bonding and reduce defects.

[0009] Accordingly, there was a need for an automotive OCA with improved plastic durability and properties.

[0010] The technical problem to be achieved by the present invention is to provide an adhesive composition having excellent durability and minimizing the occurrence of bubbles and floating by including a first polymer resin and a second polymer resin, and an adhesive film including the same.

[0011] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

[0012] One embodiment of the present invention comprises a first polymer resin and a second polymer resin, and has an elastic modulus value of 10 at -20°C. 9 Below and at 20 ℃, the elastic modulus value is 10 6 Below, an adhesive composition is provided.

[0013] According to one embodiment of the present invention, the first polymer resin and the second polymer resin may be acrylate-based polymer resins.

[0014] According to one embodiment of the present invention, the first polymer resin may be an acrylate-based prepolymer.

[0015] According to one embodiment of the present invention, the second polymer resin may be included in an amount of more than 5 parts by weight and less than 25 parts by weight with respect to 100 parts by weight of the first polymer resin.

[0016] According to one embodiment of the present invention, the weight average molecular weight (Mw) of the first polymer resin may be 500,000 or more and 3.5 million or less.

[0017] According to one embodiment of the present invention, the weight average molecular weight (Mw) of the second polymer resin may be 1,000 or more and 10,000 or less.

[0018] According to one embodiment of the present invention, the gel fraction measured after curing the adhesive composition may be 77% or more.

[0019] According to one embodiment of the present invention, the viscosity measured after curing the adhesive composition may be 2,000 cps or more and 10,000 cps or less.

[0020] One embodiment of the present invention provides an adhesive film comprising a substrate layer; and an adhesive layer; wherein the adhesive layer comprises a first polymer resin and a second polymer resin.

[0021] According to one embodiment of the present invention, the first polymer resin and the second polymer resin may be acrylate-based polymer resins.

[0022] According to one embodiment of the present invention, the first polymer resin may be an acrylate-based prepolymer.

[0023] According to one embodiment of the present invention, the second polymer resin may be included in an amount of 10 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the first polymer resin.

[0024] According to one embodiment of the present invention, the peeling force of the adhesive film for the substrate may be 2,000 gf / inch or more.

[0025] According to one embodiment of the present invention, the haze of the adhesive layer may be less than 1.0%.

[0026] According to one embodiment of the present invention, the color difference (b*) of the adhesive layer may be less than 0.5.

[0027] An adhesive composition according to one embodiment of the present invention can have excellent plastic durability and excellent printing step absorption performance by controlling the elastic modulus value.

[0028] An adhesive film according to one embodiment of the present invention can minimize the occurrence of bubbles and lifting and have excellent plastic durability.

[0029] 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.

[0030] In this specification, “A and / or B” means “A and B, or A or B.”

[0031] 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.

[0032] Hereinafter, the present invention will be described in more detail.

[0033] One embodiment of the present invention comprises a first polymer resin and a second polymer resin, and has an elastic modulus value of 10 at -20°C. 9 Below and at 20 ℃, the elastic modulus value is 10 6 The following includes an adhesive composition.

[0034] An adhesive composition according to one embodiment of the present invention can have excellent plastic durability and excellent printing step absorption performance by controlling the elastic modulus value.

[0035] According to one embodiment of the present invention, the elastic modulus value of the adhesive composition at -20°C is 9.0e +7 Ideal 2.0e +8 Below, 9.0e +7 Above 1.9e +8 Below, 9.0e +7 Above 1.8e+8 Below, 9.0e +7 Above 1.7e +8 Below, 9.1e +7 Above 1.6e +8 Below, 9.2e +7 Above 1.5e +8 Below, 9.3e +7 Above 1.4e +8 or below 9.4e +7 Above 1.3e +8 By controlling the elastic modulus value of the adhesive composition at -20°C within the above-described range, it is possible to maintain flexibility while maintaining a relatively hard state even in a low-temperature environment.

[0036] According to one embodiment of the present invention, the elastic modulus value at 20°C of the adhesive composition is 1.4e +5 Ideal 2.0e +5 Below, 1.4e +5 Above 1.9e +5 Below, 1.45e +5 Above 1.8e +5 or below 1.53e +5 Above 1.73e +5 By controlling the elastic modulus value at 20°C of the adhesive composition within the above-described range, flexibility can be maintained at general use temperatures, and deformation can be achieved even under relatively low stress.

[0037] According to one embodiment of the present invention, the first polymer resin and the second polymer resin may be acrylate-based polymer resins.

[0038] According to one embodiment of the present invention, the acrylate polymer resin may be a copolymer of acrylate monomer components. “(Meth)acrylic” means acrylic and / or methacrylic.

[0039] 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.

[0040] 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.

[0041] According to one embodiment of the present invention, the acrylate monomer may be a hydroxyl group-containing monomer, and the hydroxyl group-containing monomer may be, 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.

[0042] According to one embodiment of the present invention, the first polymer resin may be an acrylate-based prepolymer. That is, the first polymer resin may be a partially polymerized acrylate-based polymer resin.

[0043] 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 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. By selecting the acrylate-based monomer from the above, a partial polymerization can be performed to produce an adhesive composition having excellent physical properties.

[0044] According to one embodiment of the present invention, the second polymer resin may be included in an amount of more than 5 parts by weight and less than 25 parts by weight with respect to 100 parts by weight of the first polymer resin. Specifically, the second polymer resin may be included in an amount of 6 parts by weight or more and 24 parts by weight or less, 7 parts by weight or more and 23 parts by weight or less, 8 parts by weight or more and 22 parts by weight or less, 9 parts by weight or more and 21 parts by weight or less, or 10 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the first polymer resin. By adjusting the weight part of the second polymer resin within the above-described range, the plastic durability of the manufactured adhesive film can be improved, and the occurrence of bubbles and lifting can be minimized.

[0045] According to one embodiment of the present invention, the weight average molecular weight (Mw) of the first polymer resin may be 500,000 or more and 3.5 million or less. Specifically, the weight average molecular weight (Mw) of the first polymer resin may be 600,000 or more and 3.45 million or less, 700,000 or more and 3.4 million or less, 800,000 or more and 3.35 million or less, 900,000 or more and 3.3 million or less, 1 million or more and 3.25 million or less, or 1.2 million or more and 3.23 million or less. By controlling the weight average molecular weight (Mw) of the first polymer resin within the above-described range, the plastic durability of the manufactured adhesive film can be improved, and the occurrence of bubbles and lifting can be minimized.

[0046] According to one embodiment of the present invention, the viscosity of the first polymer resin may be 5,000 cps or more and 500,000 cps or less. Specifically, the viscosity of the first polymer resin may be 6,000 cps or more and 450,000 cps or less, 7,000 cps or more and 400,000 cps or less, 8,000 cps or more and 350,000 cps or less, 9,000 cps or more and 330,000 cps or less, or 10,000 cps or more and 300,000 cps or less. By controlling the viscosity of the first polymer resin within the above-described range, the plastic durability of the manufactured adhesive film can be improved, and the occurrence of bubbles and lifting can be minimized.

[0047] According to one embodiment of the present invention, the weight average molecular weight (Mw) of the second polymer resin may be 1,000 or more and 10,000 or less. Specifically, the weight average molecular weight (Mw) of the second polymer resin may be 2,000 or more and 9,000 or less, 3,000 or more and 8,000 or less, 4,000 or more and 7,000 or less, 4,500 or more and 6,000 or less, or 4,500 or more and 5,500 or less. By controlling the weight average molecular weight (Mw) of the second polymer resin within the above-described range, the plastic durability of the manufactured adhesive film can be improved, and the occurrence of bubbles and lifting can be minimized.

[0048] 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 can crosslink the acrylate polymer resin, thereby controlling the gel fraction. The multifunctional crosslinking agent may be a multifunctional (meth)acrylate. 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; and preferably hexanediol diacrylate.

[0049] 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, 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 first polymer resin.

[0050] 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.

[0051] 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 0.5 part by weight or less based on 100 parts by weight of the first polymer resin. Preferably, the amount may be 0.2 part by weight or more and 0.4 part by weight or less, and more preferably, the amount may be 0.3 part by weight.

[0052] 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.

[0053] 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 first polymer resin.

[0054] According to one embodiment of the present invention, the adhesive composition may further include a rust inhibitor. The rust inhibitor is not particularly limited, but examples thereof include amine compounds, benzotriazole-based compounds, and nitrites. In addition, examples thereof include ammonium benzoate, ammonium phthalate, ammonium stearate, ammonium palmitate, ammonium oleate, ammonium carbonate, dicyclohexylamine benzoate, urea, urotropin, thiourea, phenyl carbamate, and cyclohexylammonium-N-cyclohexylcarbamate (CHC). Furthermore, the rust inhibitor may be used singly or in combination of two or more. Preferably, it may be a benzotriazole-based compound. In particular, it is preferable that the rust inhibitor be a benzotriazole-based compound, since it can obtain a good balance of adhesive reliability, transparency, and corrosion prevention properties at a high level.

[0055] According to one embodiment of the present invention, the rust inhibitor may be included in an amount of 0.1 part by weight or more and 0.5 part by weight or less, based on 100 parts by weight of the first polymer resin. Preferably, the amount may be 0.2 part by weight or more and 0.4 part by weight or less, and more preferably, the amount may be 0.3 part by weight.

[0056] According to one embodiment of the present invention, the gel fraction measured after curing the adhesive composition may be 77% or more. Specifically, the gel fraction measured after curing the adhesive composition may be 77% or more and 95% or less, 77% or more and 94% or less, 77% or more and 92% or less, 77% or more and 90% or less, 77% or more and 88% or less, 77% or more and 86% or less, 77% or more and 84% or less, or 77% or more and 82% or less. By controlling the gel fraction measured after curing the adhesive composition within the above-described range, the plastic durability of the manufactured adhesive film can be improved, and the occurrence of bubbles and lifting can be minimized.

[0057] According to one embodiment of the present invention, the viscosity measured after curing the adhesive composition may be 2,000 cps or more and 10,000 cps or less. Specifically, the viscosity measured after curing the adhesive composition may be 3,000 cps or more and 9,500 cps or less, 4,000 cps or more and 9,000 cps or less, 5,000 cps or more and 8,500 cps or less, 6,000 cps or more and 8,500 cps or less, 7,000 cps or more and 8,500 cps or less, 7,500 cps or more and 8,400 cps or less, 7,600 cps or more and 8,300 cps or less, 7,700 cps or more and 8,200 cps or less, or 7,900 cps or more and 8,100 cps or less. By controlling the viscosity measured after curing the adhesive composition within the above-described range, the plastic durability of the manufactured adhesive film can be improved and the occurrence of bubbles and lifting can be minimized.

[0058] One embodiment of the present invention includes a substrate layer; and an adhesive layer; wherein the adhesive layer includes an adhesive film including a first polymer resin and a second polymer resin.

[0059] An adhesive film according to one embodiment of the present invention can minimize the occurrence of bubbles and lifting and have excellent plastic durability.

[0060] 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.

[0061] According to one embodiment of the present invention, the first polymer resin and the second polymer resin may be acrylate-based polymer resins.

[0062] According to one embodiment of the present invention, the first polymer resin may be an acrylate-based prepolymer.

[0063] According to one embodiment of the present invention, the second polymer resin may be included in an amount of 10 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the first polymer resin.

[0064] The contents of the first polymer resin and the second polymer resin are as described above.

[0065] According to one embodiment of the present invention, the peeling force of the adhesive film with respect to the substrate may be 2,000 gf / inch or more. Specifically, the peeling force of the adhesive film with respect to the substrate may be 2,000 gf / inch or more and 4,500 gf / inch or less, 2,500 gf / inch or more and 4,400 gf / inch or less, 2,600 gf / inch or more and 4,300 gf / inch or less, or 2,900 gf / inch or more and 4,300 gf / inch or less. By controlling the peeling force of the adhesive film with respect to the substrate within the above-described range, the durability of the plastic can be improved.

[0066] According to one embodiment of the present invention, the haze of the adhesive layer may be less than 1.0%. Specifically, the haze of the adhesive layer may be 0.3% or more and 0.9% or less, 0.4% or more and 0.8% or less, 0.42% or more and 0.7% or less, 0.44% or more and 0.65% or less, 0.46% or more and 0.6% or less, or 0.47% or more and 0.59% or less. By controlling the haze of the adhesive layer within the above-described range, the optical properties can be improved.

[0067] According to one embodiment of the present invention, the color difference (b*) of the adhesive layer may be less than 0.5. Specifically, the color difference (b*) of the adhesive layer may be 0.15 or more and 0.45 or less, 0.16 or more and 0.43 or less, 0.17 or more and 0.41 or less, 0.18 or more and 0.39 or less, 0.19 or more and 0.37 or less, or 0.20 or more and 0.36 or less. By controlling the color difference (b*) of the adhesive layer within the above-described range, the optical properties can be improved.

[0068] 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.

[0069]

[0070] <Manufacturing Example 1: Manufacturing of partially polymerized acrylate polymer resin (first polymer resin A)>

[0071] In a 3 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 60 parts by weight of ethylhexyl acrylate (EHA); 20 parts by weight of isobornyl acrylate (IBoA); and 20 parts by weight of 2-hydroxyethyl acrylate (HEA) were charged and partially polymerized (prepolymer) to obtain a syrup having a viscosity of 300,000 cps. The weight average molecular weight of the partially polymerized acrylate-based polymer resin (A) was 3.23 million.

[0072]

[0073] <Manufacturing Example 2: Manufacturing of partially polymerized acrylate polymer resin (first polymer resin B)>

[0074] In a 3 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 68 parts by weight of ethylhexyl acrylate (EHA); 14.5 parts by weight of N-pyrrolidone (NVP); and 17.5 parts by weight of 2-hydroxyethyl acrylate (HEA) were charged and partially polymerized (prepolymer) to obtain a syrup having a viscosity of 12,000 cps. The weight average molecular weight of the partially polymerized acrylate-based polymer resin (B) was 1.2 million.

[0075]

[0076] <Manufacturing Example 3: Manufacturing of partially polymerized acrylate polymer resin (first polymer resin C)>

[0077] In a 3 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 66 parts by weight of butyl acrylate (BA); 10 parts by weight of cyclohexyl acrylate (CHA); 12 parts by weight of 4-hydroxy butyl acrylate (HBA); and 12 parts by weight of 2-hydroxy ethyl acrylate (HEA) were charged and partially polymerized (prepolymer) to obtain a syrup having a viscosity of 10,000 cps. The weight average molecular weight of the partially polymerized acrylate-based polymer resin (C) was 1 million.

[0078]

[0079] <Synthesis example: Second polymer resin>

[0080] 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 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 proceed with polymerization. 2 hours after the first thermal polymerization initiator is introduced, 0.2 parts by weight of a second thermal polymerization initiator is additionally introduced. The reaction is terminated 5 hours after the second thermal polymerization 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 second polymer resin having a weight average molecular weight (Mw) of 5,000.

[0081]

[0082] <Example 1>

[0083] For 100 parts by weight of the partially polymerized (prepolymer) acrylate polymer resin (A) manufactured in the above Manufacturing Example 1, 10 parts by weight of the synthesized second polymer resin, 0.2 parts by weight of hexanediol diacrylate as a multifunctional crosslinking agent, 0.2 parts by weight of a coupling agent (KBM 403, Shin-Etsu (manufactured)), 0.3 parts by weight of a photoinitiator (Irgacure 651, Ciba Specialty Chemicals (manufactured)), and 0.3 parts by weight of a rust inhibitor (benzotriazole, Daemyung Chemical) were mixed to prepare an adhesive composition, and a coating solution having a viscosity of 8,000 cps was prepared therefrom.

[0084] Next, the manufactured coating solution was coated on a polyethylene terephthalate film (XD500P, Toray Advanced Materials, thickness: 75 ㎛) that had been subjected to release treatment using a bar coater so that the film had a thickness of 125 ㎛ after UV curing. Thereafter, the film was cured by irradiating it with ultraviolet rays using a UV lamp for 5 minutes, thereby manufacturing an adhesive film including an adhesive layer.

[0085]

[0086] <Examples 2 to 4 and Comparative Examples 1 to 3>

[0087] 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.

[0088]

[0089] First polymer resinSecond polymer resinMultifunctional crosslinking agentPhotoinitiatorCoupling agentCorrosion inhibitorExample 1A100.20.30.20.3Example 2A200.20.30.20.3Example 3B200.20.30.20.3Example 4C200.20.30.20.3Comparative Example 1A00.20.30.20.3Comparative Example 2A50.20.30.20.3Comparative Example 3A250.20.30.20.3

[0090] Unit of content: parts by weight

[0091] Multifunctional crosslinking agent: hexanediol diacrylate (HDDA)

[0092] Photoinitiator: Irgacure 651, Ciba Specialty Chemicals

[0093] Coupling agent: KBM 403, Shin-Etsu

[0094] Rust inhibitor: benzotriazole, Daemyung Chemical

[0095]

[0096] <Experimental Example>

[0097] The physical properties of the adhesive compositions and adhesive films manufactured in the above examples and comparative examples were measured using the methods presented below.

[0098]

[0099] 1. Plastic outgassing durability

[0100] The adhesive films manufactured in the above examples and comparative examples were cut to a size of 3 cm × 3 cm, attached to a plastic sheet on one side, placed on glass (0.2 T) on the other side, and then laminated by autoclaving (4 bar, 40°C, 20 min). Afterwards, bubbles and lifting were checked after 100 hours under constant temperature and humidity conditions (85°C / 85%).

[0101] Plastic durability performance was evaluated as ○ if no bubbles or bulging occurred, and Ⅹ if bubbles or bulging occurred.

[0102]

[0103] 2. Measurement of the peeling strength of the substrate

[0104] The adhesive films manufactured in the above examples and comparative examples were cut to a size of 25 mm × 20 cm (width × height), the release film was peeled off, and a 2 kg roller was attached to stainless steel (SUS 304) by reciprocating 5 times. After 20 minutes, the peeling force (gf / inch) was measured using a tensile tester under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180°.

[0105]

[0106] 3. Gel fraction

[0107] The cured product (adhesive) of the adhesive composition manufactured in the above examples and comparative examples was cut into a size of 5 cm × 5 cm, placed in a polyethylene bottle, and the weight (a) was measured. Then, ethyl acetate was added to the polyethylene bottle so that the adhesive was sufficiently immersed, and left at room temperature for 24 hours. Next, the adhesive and ethyl acetate in the polyethylene bottle were poured onto a wire mesh (weight: b) cut into a size of 14 cm × 14 cm and filtered. Thereafter, the wire mesh from which the adhesive was filtered was dried in an oven at 110°C for 2 hours, and the weight (c) was measured. Then, the measured weights a, b, and c were substituted into the following general formula 1 to measure the gel fraction (unit: %).

[0108]

[0109] <General Formula 1>

[0110] Gel fraction = ((cb) / a) × 100

[0111]

[0112] 4. White turbidity evaluation

[0113] The adhesive films of the above examples and comparative examples were attached to a glass substrate having a thickness of 1.1 T using a 2 kg roller, and a glass substrate having a thickness of 0.55 T was laminated thereon. Then, after leaving the specimen in an autoclave at 40°C and 4 bar for 20 minutes, the specimen was placed in an oven at 85°C and 85 RH% relative humidity, and after 3 days (100 hours), the occurrence of white turbidity was visually confirmed.

[0114] The performance of preventing white turbidity was evaluated as ○ if no white turbidity was observed, and Ⅹ if white turbidity was observed.

[0115]

[0116] 5. Elasticity modulus measurement method

[0117] Using the adhesive compositions manufactured in the above examples and comparative examples, an adhesive layer having a thickness of about 1 mm was manufactured. Next, the adhesive (cured product of the adhesive composition) between the release films was cut to create a cylindrical specimen measuring 8 mm × 1 mm (=diameter × thickness), and then, using a dynamic rheometer (ARES, RDA, TA Instruments Inc.), shear stress was applied between parallel plates at a frequency of 1 Hz, and the storage modulus (G') at -20°C and 20°C was measured.

[0118]

[0119] 6. Optical property measurement

[0120] Transmittance / Haze:

[0121] The adhesive layer manufactured in the above examples and comparative examples was attached to a 1.1 T glass surface in the form of glass / adhesive layer / glass, and then the transmittance / haze was measured using NDH 5000 (Nippon Denshoku).

[0122] Optical / b* measurements:

[0123] After the adhesive layer manufactured in the above examples and comparative examples was attached to a 1.1 T glass surface in the form of glass / adhesive layer / glass, the color difference (b*) was measured using CM-3600A (Konica minolta).

[0124]

[0125] 7. Printing steps

[0126] The adhesive layers manufactured in the above examples and comparative examples were laminated on the printed step (black, 70 um) and processed in an autoclave (4 bar, 40°C, 20 min) to perform lamination. Afterwards, bubbles and lifting were confirmed after 100 hours under constant temperature and humidity conditions (85°C / 85%).

[0127] The printing step performance was evaluated as ○ if no bubbles or bulging occurred, and Ⅹ if bubbles or bulging occurred.

[0128]

[0129] G'(-20℃)G'(20℃)Base peel strength(gf / inch)Color difference(b*)Haze(%)Gel fraction(%)PC plastic durabilityPrinting step(~70㎛)White turbidity EvaluationExample 11.16e +8 1.57e +5 4,0000.220.4782○○○Example 21.30e +8 1.68e +5 4,3000.200.4977○○○Example 39.40e +7 1.73e +5 3,0000.360.5578○○○Example 41.10e +8 1.53e +5 2,9000.320.5980○△○Comparative Example 18.25e +7 1.44e +5 3,5000.230.4582X○XComparative example 29.75e +7 1.54e +5 3,8500.220.4680X○XComparative Example 31.65e +8 1.71e +5 4,6200.250.5074XXX

[0130]

[0131] As shown in Table 2 above, the adhesive films manufactured in Examples 1 to 4 according to the present invention have a gel fraction of 77% or more, exhibit good plastic durability and printing step performance without bubbles or lifting, and exhibit anti-whitening properties as no whitening occurs in the whitening evaluation. In addition, the films exhibit excellent haze and optical properties, confirming their suitability for use as optical adhesive films.

[0132] On the other hand, when the second polymer resin is less than 5 parts by weight, as in Comparative Examples 1 and 2, it can be confirmed that the plastic durability and anti-whitening performance are inferior, and when the second polymer resin is more than 25 parts by weight, as in Comparative Example 3, it can be confirmed that not only the plastic durability and anti-whitening performance are inferior, but also the printing step performance is inferior.

[0133] Therefore, the adhesive composition according to one embodiment of the present invention and the adhesive film including the same include the first polymer resin and the second polymer resin, thereby minimizing the occurrence of bubbles and lifting and providing excellent plastic durability.

Claims

1. Containing a first polymer resin and a second polymer resin, The elastic modulus value at -20 ℃ is 10 9 Below and at 20 ℃, the elastic modulus value is 10 6 Below, adhesive composition.

2. In claim 1, An adhesive composition wherein the first polymer resin and the second polymer resin are acrylate-based polymer resins.

3. In claim 1, An adhesive composition wherein the first polymer resin is an acrylate-based prepolymer.

4. In claim 1, An adhesive composition, wherein the second polymer resin is included in an amount of more than 5 parts by weight and less than 25 parts by weight based on 100 parts by weight of the first polymer resin.

5. In claim 1, An adhesive composition, wherein the weight average molecular weight (Mw) of the first polymer resin is 500,000 or more and 3.5 million or less.

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

7. In claim 1, An adhesive composition, wherein the gel fraction measured after curing the adhesive composition is 77% or more.

8. In claim 1, An adhesive composition, wherein the viscosity measured after curing the adhesive composition is 2,000 cps or more and 10,000 cps or less.

9. Base layer; and It includes an adhesive layer; An adhesive film, wherein the adhesive layer comprises a first polymer resin and a second polymer resin.

10. In claim 9, An adhesive film wherein the first polymer resin and the second polymer resin are acrylate-based polymer resins.

11. In claim 9, An adhesive film wherein the first polymer resin is an acrylate-based prepolymer.

12. In claim 9, An adhesive film, wherein the second polymer resin is contained in an amount of 10 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the first polymer resin.

13. In claim 9, An adhesive film having a peeling strength of 2,000 gf / inch or more for the substrate of the adhesive film.

14. In claim 9, An adhesive film, wherein the haze of the adhesive layer is less than 1.0%.

15. In claim 9, An adhesive film, wherein the color difference (b*) of the adhesive layer is less than 0.5.