Adhesive composition and adhesive film comprising same

Abstract

The present invention relates to an adhesive composition and an adhesive film comprising same and, more particularly, to an adhesive composition capable of improving durability by comprising an acrylate-based prepolymer that is partially polymerized by including at least one acrylate-based monomer and a first tackifier, and to an adhesive film comprising same.

Description

Adhesive composition and adhesive film comprising the same

[0001] This invention claims the benefit of patent application No. 10-2024-0097962 filed with the Korean Intellectual Property Office on July 24, 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 capable of improving durability by including an acrylate prepolymer partially polymerized with at least one acrylate monomer and a first tackifier, 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 lifting by including a partially polymerized acrylate prepolymer including at least one acrylate monomer and a first tackifier, 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 will be clearly understood by those skilled in the art from the description below.

[0012] According to one embodiment of the present invention, an adhesive composition is provided, which includes a partially polymerized acrylate prepolymer including one or more acrylate monomers and a first tackifier.

[0013] According to one embodiment of the present invention, the one or more acrylate monomers may be one selected from the group consisting of butyl acrylate (BA), ethyl hexyl acrylate (EHA), isobornyl acrylate (IBoA), 2-hydroxyethyl acrylate (HEA), hydroxy propyl acrylate (HPA), 4-hydroxy butyl acrylate (HBA), and polymethyl methacrylate (PMMA).

[0014] According to one embodiment of the present invention, the one or more acrylate monomers may include a soft monomer, a functional monomer, and a hard monomer.

[0015] According to one embodiment of the present invention, the acrylate-based prepolymer may contain a soft monomer in an amount of 45 parts by weight or more and 80 parts by weight or less based on 100 parts by weight of the total.

[0016] According to one embodiment of the present invention, the acrylate-based prepolymer may contain a functional monomer in an amount of 15 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the total.

[0017] According to one embodiment of the present invention, the adhesive composition may contain a first tackifier in an amount of 1 part by weight or more and 10 parts by weight or less, based on 100 parts by weight of the acrylate-based prepolymer.

[0018] According to one embodiment of the present invention, the adhesive composition may further include a second tackifier.

[0019] According to one embodiment of the present invention, the adhesive composition may contain a second tackifier in an amount of 1 part by weight or more and less than 10 parts by weight based on 100 parts by weight of the acrylate-based prepolymer.

[0020] According to one embodiment of the present invention, the glass transition temperature (Tg) of the adhesive composition may be -50°C or higher.

[0021] According to one embodiment of the present invention, the adhesive composition may further include a multifunctional crosslinking agent, a photoinitiator, and a coupling agent.

[0022] One embodiment of the present invention comprises a substrate layer; and an adhesive layer; wherein the adhesive layer may include an acrylate prepolymer in which at least one acrylate monomer and a first tackifier are partially polymerized.

[0023] According to one embodiment of the present invention, the difference (△2θ) between the maximum peak and minimum peak of the XRD acrylic of the adhesive film may be 9.0 or more and 14.0 or less.

[0024] According to one embodiment of the present invention, the peeling force of the adhesive film for the substrate may be greater than 300 gf / inch.

[0025] According to one embodiment of the present invention, the haze of the adhesive layer may be less than 1.12%.

[0026] An adhesive composition according to one embodiment of the present invention may have excellent viscoelasticity by including a partially polymerized acrylate prepolymer including at least one acrylate monomer and a first tackifier.

[0027] An adhesive film according to one embodiment of the present invention can minimize the occurrence of bubbles and lifting and have excellent durability.

[0028] 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.

[0029] In this specification, “A and / or B” means “A and B, or A or B.”

[0030] In this specification, “about,” “approximately,” and “substantially” are used to mean a range of or approximation to a numerical value or degree, taking into account inherent manufacturing and material tolerances, and are used to prevent infringers from unfairly using the disclosure, which mentions exact or absolute numbers provided to aid understanding of the present invention.

[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 includes an adhesive composition comprising a partially polymerized acrylate prepolymer including at least one acrylate and a first tackifier.

[0034] An adhesive composition according to one embodiment of the present invention may have excellent viscoelasticity by including a partially polymerized acrylate prepolymer including at least one acrylate monomer and a first tackifier.

[0035] According to one embodiment of the present invention, the one or more acrylate monomers may be one selected from the group consisting of butyl acrylate (BA), ethyl hexyl acrylate (EHA), isobornyl acrylate (IBoA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), 4-hydroxy butyl acrylate (HBA), and polymethyl methacrylate (PMMA). By selecting the one or more acrylate monomers within the above-described range, the viscoelasticity of the pressure-sensitive adhesive composition can be controlled.

[0036] According to one embodiment of the present invention, the polymethyl methacrylate (PMMA) acrylate monomer can function as a first tackifier at the same time.

[0037] According to one embodiment of the present invention, the at least one acrylate monomer may include a soft monomer, a functional monomer, and a hard monomer. As described above, the at least one acrylate monomer may impart adhesiveness, cohesiveness, and functionality to the pressure-sensitive adhesive composition by including the soft monomer, the functional monomer, and the hard monomer. In contrast, if the at least one acrylate monomer does not include all of the soft monomer, the functional monomer, and the hard monomer, durability may be reduced.

[0038] According to one embodiment of the present invention, the soft monomer is used to impart adhesiveness and has a glass transition temperature (Tg) lower than room temperature. Specifically, it may be one selected from the group consisting of butyl acrylate (BA), ethyl hexyl acrylate (EHA), and lauryl acrylate (LA). Preferably, it may be one selected from the group consisting of butyl acrylate (BA) and ethyl hexyl acrylate (EHA).

[0039] According to one embodiment of the present invention, the functional monomer is used to add a functional group, and the functional monomer may be at least one of acrylic acid or methacrylic acid monomers having a carboxyl group, 2-hydroxyethyl acrylate (HEA), 2-hydroxypropyl acrylate (HPA), 4-hydroxybutyl acrylate (HBA) monomers having a hydroxyl group, and glycidyl methacrylate monomers having a glycidyl group. Preferably, it may be one selected from the group consisting of 2-hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA) and 4-hydroxybutyl acrylate (HBA).

[0040] According to one embodiment of the present invention, the hard monomer is used to impart cohesion to the adhesive, and specifically, may be one selected from the group consisting of methyl methacrylate, styrene, acrylonitrile, vinyl acetate, and isobornyl acrylate (IBoA). Preferably, it may be one selected from the group consisting of methyl methacrylate and isobornyl acrylate (IBoA).

[0041] According to one embodiment of the present invention, the methyl methacrylate can function as a hard monomer and at the same time perform a first tackifier function.

[0042] According to one embodiment of the present invention, the acrylate-based prepolymer may contain a soft monomer in an amount of 45 parts by weight or more and 80 parts by weight or less, based on 100 parts by weight of the total. Specifically, the acrylate-based prepolymer may contain a soft monomer in an amount of 50 parts by weight or more and 80 parts by weight or less, 55 parts by weight or more and 75 parts by weight or less, 60 parts by weight or more and 70 parts by weight or less, or 60 parts by weight or more and 65 parts by weight or less, based on 100 parts by weight of the total. If the amount exceeds the above-described range, durability may be reduced, and if the amount falls short of the above-described range, adhesiveness may be reduced.

[0043] According to one embodiment of the present invention, the acrylate-based prepolymer may contain a functional monomer in an amount of 15 parts by weight or more and 50 parts by weight or less, based on 100 parts by weight of the total. Specifically, the acrylate-based prepolymer may contain a functional monomer in an amount of 16 parts by weight or more and 49 parts by weight or less, 17 parts by weight or more and 48 parts by weight or less, 18 parts by weight or more and 47 parts by weight or less, 19 parts by weight or more and 46 parts by weight or less, or 20 parts by weight or more and 45 parts by weight or less, based on 100 parts by weight of the total. By adjusting the weight part of the functional monomer within the above-described range, a functional group can be appropriately provided.

[0044] According to one embodiment of the present invention, the acrylate-based prepolymer may contain a hard monomer in an amount of 1 part by weight or more and 25 parts by weight or less, based on 100 parts by weight of the total. Specifically, the acrylate-based prepolymer may contain a hard monomer in an amount of 1 part by weight or more and 24 parts by weight or less, 1 part by weight or more and 23 parts by weight or less, 1 part by weight or more and 22 parts by weight or less, or 1 part by weight or more and 21 parts by weight or less, based on 100 parts by weight of the total. By adjusting the weight part of the hard monomer within the above-described range, cohesive force can be appropriately provided.

[0045] According to one embodiment of the present invention, the hard monomer contains polymethyl methacrylate (PMMA) that performs a first tackifier function, which is 1 part by weight or more and 25 parts by weight or less.

[0046] According to one embodiment of the present invention, the adhesive composition may contain a first tackifier in an amount of 1 to 10 parts by weight based on 100 parts by weight of the acrylate-based prepolymer. Specifically, the first tackifier may be polymethyl methacrylate (PMMA). As described above, by adjusting the weight portion of the first tackifier, adhesion and durability can be improved.

[0047] According to one embodiment of the present invention, the adhesive composition may further include a second tackifier. As described above, the adhesive composition can further improve adhesion and durability by further including the second tackifier.

[0048] According to one embodiment of the present invention, the second tackifier may be polymethyl methacrylate (PMMA). As described above, the second tackifier can improve adhesion by selecting polymethyl methacrylate (PMMA).

[0049] According to one embodiment of the present invention, the pressure-sensitive adhesive composition may contain a second tackifier in an amount of 1 part by weight or more and less than 10 parts by weight based on 100 parts by weight of the acrylate-based prepolymer. Specifically, the pressure-sensitive adhesive composition may contain a second tackifier in an amount of 1 part by weight or more and less than 9 parts by weight based on 100 parts by weight of the acrylate-based prepolymer. By adjusting the weight part of the second tackifier within the above-described range, the adhesiveness can be improved.

[0050] According to one embodiment of the present invention, the glass transition temperature (Tg) of the adhesive composition may be -50°C or higher. Specifically, the glass transition temperature (Tg) of the adhesive composition may be -50°C or higher and -30°C or lower. By controlling the glass transition temperature (Tg) of the adhesive composition within the above-described range, the adhesiveness and durability may be improved. Furthermore, the higher the glass transition temperature (Tg) of the adhesive composition, the smaller the difference (△2θ) between the maximum and minimum peaks of the XRD acrylic of the adhesive film, and conversely, the lower the glass transition temperature (Tg) of the adhesive composition, the larger the difference (△2θ) between the maximum and minimum peaks of the XRD acrylic of the adhesive film.

[0051] According to one embodiment of the present invention, the adhesive composition may further include a multifunctional crosslinking agent, a photoinitiator, and a coupling agent.

[0052] According to one embodiment of the present invention, the pressure-sensitive adhesive composition may further comprise a multifunctional crosslinking agent. By further comprising the multifunctional crosslinking agent, the pressure-sensitive adhesive composition prepared by crosslinking an acrylate-based prepolymer exhibits higher substrate peel strength than before, satisfies durability, and suppresses defects such as lifting and bubble generation. 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; Preferably, the polyfunctional crosslinking agent may be hexanediol diacrylate (HDDA).

[0053] 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 peeling strength than before, satisfy durability, and suppress defects such as lifting and bubble generation.

[0054] 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.

[0055] 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, 0.25 part by weight or more and 0.35 part by weight or less, or 0.27 part by weight or more and 0.33 part by weight or less based on 100 parts by weight of the acrylate-based prepolymer, and preferably, it may be 0.3 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 durability, and suppressing defects such as lifting and bubble generation.

[0056] 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.

[0057] 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.

[0058] 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 durability, and suppresses defects such as lifting and bubble generation.

[0059] According to one embodiment of the present invention, the pressure-sensitive adhesive composition may further include a chain transfer agent (CTA). Specifically, the chain transfer agent may be included in an amount of 0.05 parts by weight or more and 0.2 parts by weight or less, and preferably 0.1 parts by weight, based on 100 parts by weight of the acrylate-based prepolymer. As described above, by further including a chain transfer agent (CTA), the pressure-sensitive adhesive composition can be implemented as soft, thereby further improving durability.

[0060] One embodiment of the present invention includes a substrate layer; and an adhesive layer; wherein the adhesive layer includes an adhesive film including a prepolymer in which at least one acrylate monomer and a first tackifier are partially polymerized.

[0061] An adhesive film according to one embodiment of the present invention can minimize the occurrence of bubbles and lifting and have excellent durability.

[0062] 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.

[0063] According to one embodiment of the present invention, the content of the acrylate prepolymer in which at least one acrylate monomer and the first tackifier are partially polymerized is as described above.

[0064] According to one embodiment of the present invention, the difference (△2θ) between the maximum peak and the minimum peak of the XRD acrylic of the adhesive film may be 9.0 or more and 14.0 or less. Specifically, the difference (△2θ) between the maximum peak and the minimum peak of the XRD acrylic of the adhesive film may be 9.0 or more and 14.0 or less, 9.1 or more and 13.8 or less, 9.2 or more and 13.6 or less, 9.3 or more and 13.4 or less, 9.4 or more and 13.2 or less, 9.5 or more and 13.0 or less, 9.6 or more and 12.8 or less, 9.7 or more and 12.6 or less, 9.8 or more and 12.4 or less, 9.9 or more and 12.2 or less, 9.9 or more and 12.0 or less, 9.9 or more and 11.8 or less, or 9.9 or more and 11.7 or less. If the above-mentioned range is exceeded, the adhesive composition may be soft, resulting in poor durability and gel fraction properties. If the above-mentioned range is not met, the adhesive composition may be hard, resulting in high gel fraction properties, and staining problems may occur when attached to a substrate.

[0065] According to one embodiment of the present invention, the peeling force of the adhesive film with respect to the substrate may be greater than 300 gf / inch. Specifically, the peeling force of the adhesive film with respect to the substrate may be 500 gf / inch or more and 5,000 gf / inch or less, 1,000 gf / inch or more and 4,000 gf / inch or less, 1,500 gf / inch or more and 3,900 gf / inch or less, or 2,000 gf / inch or more and 3,800 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.

[0066] According to one embodiment of the present invention, the haze of the adhesive layer may be less than 1.12%. Specifically, the haze of the adhesive layer may be 0.3% or more and 1.1% or less, 0.35% or more and 1.05% or less, 0.4% or more and 1.0% or less, or 0.45% or more and 0.99% or less. By controlling the haze of the adhesive layer within the above-described range, the optical properties can be improved.

[0067] 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.

[0068]

[0069] Manufacturing Example 1. Manufacturing of acrylate prepolymer (A)

[0070] In a 1 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 30 parts by weight of butyl acrylate (BA); 30 parts by weight of ethyl hexyl acrylate (EHA); 20 parts by weight of isobornyl acrylate (IBoA); 20 parts by weight of 2-hydroxyethyl acrylate (HEA); and 1 part by weight of a low molecular weight PMMA (molecular weight 10,000) were charged and partially polymerized to obtain a syrup having a viscosity of 19,200 cps. The weight average molecular weight of the acrylate prepolymer (A, 100 parts by weight) was 2,020,000.

[0071]

[0072] Manufacturing Example 2. Manufacturing of acrylate prepolymer (B)

[0073] In a 1 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 65 parts by weight of butyl acrylate (BA); 10 parts by weight of isobornyl acrylate (IBoA); 20 parts by weight of hydroxypropyl acrylate (HPA); and 5 parts by weight of low molecular weight PMMA (molecular weight 10,000) were charged and partially polymerized to obtain a syrup having a viscosity of 15,000 cps. The weight average molecular weight of the acrylate prepolymer (B, 100 parts by weight) was 2 million.

[0074]

[0075] Manufacturing Example 3. Manufacturing of acrylate prepolymer (C)

[0076] In a 1 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 60 parts by weight of butyl acrylate (BA); 10 parts by weight of isobornyl acrylate (IBoA); 20 parts by weight of 2-hydroxyethyl acrylate (HEA); and 10 parts by weight of a low molecular weight PMMA (molecular weight 10,000) were charged and partially polymerized to obtain a syrup having a viscosity of 20,000 cps. The weight average molecular weight of the acrylate prepolymer (C, 100 parts by weight) was 2.5 million.

[0077]

[0078] Manufacturing Example 4. Manufacturing of acrylate prepolymer (D)

[0079] In a 1 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 60 parts by weight of butyl acrylate (BA); 25 parts by weight of 4-hydroxy butyl acrylate (HBA); 14 parts by weight of 2-hydroxyethyl acrylate (HEA); and 1 part by weight of a low molecular weight PMMA (molecular weight 10,000) were charged and partially polymerized to obtain a syrup having a viscosity of 19,000 cps. The weight average molecular weight of the acrylate prepolymer (D, 100 parts by weight) was 2 million.

[0080]

[0081] Manufacturing Example 5. Manufacturing of acrylate prepolymer (E)

[0082] In a 1 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 60 parts by weight of butyl acrylate (BA); 25 parts by weight of 4-hydroxy butyl acrylate (HBA); 20 parts by weight of 2-hydroxyethyl acrylate (HEA); and 5 parts by weight of low molecular weight PMMA (molecular weight 10,000) were charged and partially polymerized to obtain a syrup having a viscosity of 19,300 cps. The weight average molecular weight of the acrylate prepolymer (E, 100 parts by weight) was 1,900,000.

[0083]

[0084] Manufacturing Example 6. Manufacturing of acrylate prepolymer (F)

[0085] In a 1 L reactor equipped with a cooling device for easy temperature control and refluxing nitrogen gas, 50 parts by weight of ethyl hexyl acrylate (EHA); 40 parts by weight of lauryl acrylate (LA); and 10 parts by weight of 4-hydroxy butyl acrylate (HBA) were charged and partially polymerized to obtain a syrup having a viscosity of 20,000 cps. The weight average molecular weight of the acrylate prepolymer (F, 100 parts by weight) was 2.1 million.

[0086]

[0087] <Example>

[0088] Example 1

[0089] For 100 parts by weight of the acrylate prepolymer (A) manufactured in Manufacturing Example 1, 0.15 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 1.0 parts by weight of PMMA low molecular weight (molecular weight 10,000) were mixed to manufacture an adhesive composition, from which an adhesive layer coating liquid having a viscosity of 2,000 to 3,000 cps was manufactured.

[0090] Next, the manufactured adhesive layer coating solution was coated on a polyethylene terephthalate film (ROH751, Toray Advanced Materials, thickness: 75 ㎛) that had been subjected to UV curing using a bar coater to form an adhesive layer with a thickness of 250 ㎛.

[0091] After this, an adhesive film was manufactured by curing it by irradiating it with ultraviolet rays using a UV lamp for 5 minutes.

[0092]

[0093] Examples 2 to 7 and Comparative Examples 1 to 3

[0094] 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.

[0095]

[0096] Acrylate prepolymer (by weight) Multifunctional crosslinking agent Photoinitiator Coupling agent Chain transfer agent 1 Tackifier 2 Adhesive Example 1A (100) 0.15 0.30 2-1 Example 2B (100) 0.15 0.30 2-5 Example 3C (100) 0.15 0.30 2-10 Example 4D (100) 0.15 0.30 20 114 Example 5E (100) 0.15 0.30 20 15 Example 6D (100) 0.15 0.30 20 11 Example 7D (100) 0.15 0.30 20 119 Comparative Example 1D (100) 0.15 0.30 2-1 Comparative Example 2D (100) 0.15 0.30 2-110 Comparative Example 3F (100) 0.15 0.30 2---

[0097]

[0098] Unit of content: parts by weight

[0099] Multifunctional crosslinking agent: hexanediol diacrylate

[0100] Coupling agent: KBM 403, Shin-Etsu

[0101] Photoinitiator: Irgacure 651, Ciba Specialty Chemicals

[0102] Chain transfer agent (CTA): Chain transfer agent (AMSD-GRH, GOI CHEMICAL)

[0103] First tackifier: polymethyl methacrylate (PMMA)

[0104] Second tackifier: polymethyl methacrylate (PMMA)

[0105]

[0106] <Experimental Example>

[0107] The physical properties of the adhesive films manufactured in the above examples and comparative examples were measured using the methods presented below.

[0108]

[0109] 1. XRD analysis evaluation of the adhesive layer

[0110] The 2-theta value (2θ) of the surface of the adhesive film manufactured in the above examples and comparative examples was measured using an XRD analysis device (X-ray diffraction analyzer: model name Ultima-4).

[0111]

[0112] 2. Gel fraction

[0113] The cured product (adhesive) of the adhesive composition 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. Then, 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.

[0114] Next, the measured weights a, b, and c were substituted into Equation 1 below to measure the gel fraction (unit: %).

[0115] [Formula 1]

[0116] Gel fraction = ((cb) / a) × 100

[0117]

[0118] 3. Swelling index measurement

[0119] The swelling index of the adhesive compositions manufactured in the above examples and comparative examples was measured as follows.

[0120] Swelling index = weight of swollen gel (g) / weight of gel (g)

[0121]

[0122] 4. Dielectric constant measurement

[0123] The dielectric properties were evaluated by measuring the relative permittivity at a frequency of 100 kHz using an impedance analyzer 4294A from Agilent according to the ASTM D150 standard.

[0124]

[0125] 5. Measurement of the peeling strength of the substrate

[0126] 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 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°.

[0127]

[0128] 6. Optical property measurement

[0129] Transmittance / Haze:

[0130] After attaching the manufactured adhesive layer to a 1.1 T glass surface in the form of glass / adhesive layer / glass, the transmittance / haze was measured using NDH 5000 (Nippon Denshoku).

[0131] b*(color difference) measurement:

[0132] After attaching the manufactured adhesive layer to a 1.1 T glass surface in the form of glass / adhesive layer / glass, the color difference was measured using CM-3600A (Konica minolta).

[0133]

[0134] 7. Durability

[0135] The adhesive films manufactured in the above examples and comparative examples were evaluated under a high temperature and constant temperature and humidity atmosphere for 1,000 hours after being configured as follows, and then bubbles and lifting were confirmed.

[0136] If no bubbles or bubbles were formed, it was evaluated as ○, and if bubbles or bubbles were formed, it was evaluated as X.

[0137] Stack 1. Glass / PSA / Pol / OCA / Glass (Pol: LG chem. clear Pol)

[0138] Stack 2. Glass / OCA / Glass

[0139]

[0140] 8. Evaluation of anti-whitening performance

[0141] The above adhesive film was 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, it was left in an autoclave at 40°C and 4 bar for 20 minutes, and then irradiated with 3 J of ultraviolet light.

[0142] Furthermore, the specimens after UV irradiation were placed in an oven at a temperature of 85°C and a relative humidity of 85% RH, and the occurrence of white turbidity was visually checked after 3 days.

[0143] The performance of preventing white turbidity was evaluated as ○ if no white turbidity was observed, and Ⅹ if white turbidity was observed.

[0144]

[0145]

[0146]

[0147] As can be confirmed in Table 2 above, the adhesive films manufactured in Examples 1 to 7 according to the present invention satisfy XRD 9.9 < △2θ < 11.7, and it can be confirmed that there are no bubbles or floating under high temperature and constant temperature and humidity conditions after glass lamination. Therefore, it can be confirmed that there is no white clouding and the reliability is excellent. In addition, it can be confirmed that there is no problem in using it as an optical adhesive film because the haze and optical properties are excellent.

[0148] On the other hand, if the total content of the first tackifier and the second tackifier is 1 part by weight or less (Comparative Example 1) or more than 10 parts by weight (Comparative Example 2), cloudiness occurs and bubbles are formed under high-temperature evaluation and constant temperature and humidity conditions, making it unsuitable for durability.

[0149] However, in the case of Example 6, it can be confirmed that durability is excellent even though the total content of the first adhesive agent and the second adhesive agent is 1 part by weight, including the chain transfer agent.

[0150] In addition, as in Comparative Example 3, it can be confirmed that even when an acrylate monomer is used as an excessive amount of soft monomer, the durability and XRD values ​​are not satisfactory.

[0151] Therefore, the adhesive composition according to one embodiment of the present invention and the adhesive film including the same include an acrylate prepolymer in which at least one acrylate monomer and a first tackifier are partially polymerized, thereby minimizing the occurrence of bubbles and lifting and improving durability.

Claims

An adhesive composition comprising a partially polymerized acrylate prepolymer comprising at least one acrylate monomer and a first tackifier.

2. In claim 1, The above one or more acrylate monomers are, An adhesive composition, wherein the adhesive composition is one selected from the group consisting of butyl acrylate (BA), ethyl hexyl acrylate (EHA), isobornyl acrylate (IBoA), 2-hydroxyethyl acrylate (HEA), hydroxy propyl acrylate (HPA), 4-hydroxy butyl acrylate (HBA), and polymethyl methacrylate (PMMA).

3. In claim 1, The above one or more acrylate monomers are, An adhesive composition comprising a soft monomer, a functional monomer and a hard monomer.

4. In claim 3, An adhesive composition, wherein the above acrylate prepolymer contains a soft monomer in an amount of 45 parts by weight or more and 80 parts by weight or less based on 100 parts by weight of the total.

5. In claim 3, An adhesive composition, wherein the acrylate prepolymer contains a functional monomer in an amount of 15 parts by weight or more and 50 parts by weight or less, based on 100 parts by weight of the total.

6. In claim 1, The adhesive composition comprises a first tackifier in an amount of 1 part by weight or more and 10 parts by weight or less, based on 100 parts by weight of the acrylate-based prepolymer.

7. In claim 1, An adhesive composition, wherein the adhesive composition further comprises a second tackifier.

8. In claim 7, An adhesive composition comprising a second tackifier in an amount of 1 part by weight or more and less than 10 parts by weight based on 100 parts by weight of the acrylate-based prepolymer.

9. In claim 1, An adhesive composition, wherein the glass transition temperature (Tg) of the adhesive composition is -50°C or higher.

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

11. Base layer; and It includes an adhesive layer; An adhesive film, wherein the adhesive layer comprises an acrylate prepolymer in which at least one acrylate monomer and a first tackifier are partially polymerized.

12. In claim 11, An adhesive film, wherein the difference (△2θ) between the maximum and minimum peaks of the XRD acrylic of the above adhesive film is 9.0 or more and 14.0 or less.

13. In claim 11, An adhesive film having a peeling strength of more than 300 gf / inch for the substrate of the adhesive film.

14. In claim 11, An adhesive film, wherein the haze of the adhesive layer is less than 1.12%.

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