KR102166468B1 - Pressure sensitive adhesive composition and article comprising the same - Google Patents

Abstract

The present application relates to a pressure-sensitive adhesive composition, an adhesive article including the same. According to the present application, an adhesive film having excellent durability, step overcoming properties, and cutting properties may be provided.

Description

Pressure sensitive adhesive composition and article comprising the same}

The present application relates to an adhesive composition and an adhesive article including the same.

An optically clear adhesive film called OCA (optically clear adhesive) or OCR (optically clear resin) can be used in a variety of fields. For example, a film-type touch screen panel and a liquid crystal display (LCD) are used in electronic devices having a display device such as a mobile phone, and the air gap between them is attached while attaching the components to each other. OCA or OCR can be used to fill the gap). Such an optically transparent adhesive film is known to provide advantages in improving the overall durability of the display, such as realization of high transmittance, high brightness and CR improvement through securing low reflection characteristics, and improvement of overall durability of the display, such as moisture impregnation, vibration resistance, and impact resistance.

In the case of an electronic device in which an optically transparent adhesive film is used, a component having a step may be included. For example, a printed circuit board (Rigid Printed Circuit Board or Flexible Printed Circuit Board) having a step difference due to a printed pattern or the like may be used as a component of an electronic device. In this case, overcoming (absorbing) the step is a very important task.

With regard to overcoming the step difference, in the prior art, it was considered to use a polymer resin having relatively high viscoelasticity (for example, a low glass transition temperature).In the case of an OCA or OCR film to which such a resin is applied, the productivity related to film cutting It is low and has the disadvantage of poor durability. In this regard, Korean Patent Registration No. 10-1393986 has proposed a method of additionally forming a hard layer in order to solve the problem of low cutting properties of a resin having high viscoelasticity, but the process becomes complicated. There is a problem with poor film formation efficiency.

An object of the present application is to provide a pressure-sensitive adhesive film having excellent step overcoming (absorption) properties for a substrate to be attached and at the same time excellent in durability under high temperature and/or high humidity conditions.

Another object of the present application is to provide an adhesive film having good cutting productivity and excellent process yield.

Another object of the present application is to provide an adhesive article including the adhesive film.

All of the above and other objects of the present application can be solved by the present application described in detail below.

In one example related to the present application, the present application relates to a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition is a constitution that can be used in an electronic device or an optical device, and the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is effective in absorbing the level difference of the devices. In the present application, when the adhesive layer absorbs the step, it means that when the step of the adhesive article and the adhesive layer come into contact, the step is accommodated in the adhesive layer without bubbles, peeling, or separation of the adhesive layer near the step. do.

The pressure-sensitive adhesive composition may include at least two or more block copolymers having different molecular weights. In the present application, the term "block copolymer" may refer to a copolymer including blocks of different polymerized monomers. The specific configuration related to the glass transition degree of the block copolymer will be described below.

Among the blocks included in the block copolymer, a block having a relatively high glass transition temperature may form a hard segment (or a hard block) that imparts relatively rigid characteristics to the block copolymer. The hard segment may exist in a glass form at room temperature, and may impart cohesive strength and durability to the pressure-sensitive adhesive including the block copolymer. The hard segment may be referred to as a first block. Specifically, the hard segment may be referred to as a block 1A (hard segment of the block copolymer (A)) and a block 1B (hard segment of the block copolymer (B)) according to the type of the block copolymer it is included in. have. For reference, in the present application, room temperature refers to a temperature in a specially reduced or not heated state, and may be, for example, a temperature within a range of 18 to 30°C or a temperature within a range of 22 to 27°C.

Among the blocks included in the block copolymer, a block having a relatively low glass transition temperature may form a soft segment (or soft block) that imparts relatively soft physical properties in the block copolymer. The soft segment may have molecular flow at room temperature and may impart stress relaxation properties to the pressure-sensitive adhesive including the block copolymer. The soft segment may be referred to as a second block. Specifically, the soft segment may be referred to as a 2A block (soft segment of the block copolymer (A)) and a 2B block (soft segment of the block copolymer (B)) according to the type of the block copolymer it is included in. have.

As described above, the copolymer including both the hard segment and the soft segment may form a fine phase-separated structure in the adhesive. Since the block copolymer exhibits appropriate cohesive strength and stress relaxation properties according to temperature changes, interfacial adhesion, high temperature or high humidity durability reliability can be improved.

Specifically, the pressure-sensitive adhesive composition of the present application includes a block copolymer (A) including at least two blocks having different glass transition temperatures; And a block copolymer (B) including at least two blocks having different molecular weights and different glass transition temperatures from the block copolymer (A).

In the present application, the pressure-sensitive adhesive composition includes two or more block copolymers having different molecular weights. Specifically, the block copolymer (A) may be a copolymer having a lower molecular weight than the block copolymer (B). Unless otherwise defined in the present application, the molecular weight may be a number average molecular weight (Mn). The number average molecular weight referred to in the present application can be measured according to the method presented in Examples using, for example, GPC (Gel Permeation Chromatograph). The specific configuration related to the molecular weight of the block copolymer will be described below.

In the present application, each block copolymer included in the pressure-sensitive adhesive composition may have different crosslinking properties. Specifically, the block copolymer (A) having a relatively small molecular weight may be a non-crosslinkable polymer, and the block copolymer (B) having a relatively large molecular weight may be a crosslinkable polymer. In the present application, the "crosslinkable" polymer may refer to a polymer including a crosslinkable functional group that can be used to form a crosslinked structure of the pressure-sensitive adhesive by reacting with a crosslinking agent. The low molecular weight non-crosslinkable block copolymer (A) imparts advantageous properties to the pressure-sensitive adhesive for overcoming the step difference, and the high molecular weight cross-linkable block copolymer (B) may impart durability to the pressure-sensitive adhesive. The specific configuration related to the crosslinking properties will be described below.

In one example, the number average molecular weight (Mn) of the block copolymer (A) may be in the range of 50,000 to 200,000. More specifically, the block copolymer (A) may have a number average molecular weight of 55,000 or more, 60,000 or more, 65,000 or more, 70,000 or more, 75,000 or more, or 80,000 or more, and 180,000 or less, 160,000 or less, 140,000 or less, 120,000 or less, or It can have a number average molecular weight of 100,000 or less.

In one example, the number average molecular weight of the block 1A may be in the range of 2,500 to 100,000. Specifically, the number average molecular weight of the block 1A may be 10,000 or more, 15,000 or more, 20,000 or more, 25,000 or more, 30,000 or more, 35,000 or more, 40,000 or more, or 45,000 or more, and 90,000 or less, 85,000 or less, 80,000 or less, 75,000 or less , 70,000 or less, 65,000 or less, 60,000 or less, or 55,000 or less.

In one example, the number average molecular weight (Mn) of the block copolymer (B) may be 100,000 or more, assuming that it is greater than the number average molecular weight (Mn) of the block copolymer (A). For example, the number average molecular weight (Mn) of the block copolymer (B) may be 150,000 or more or 200,000 or more.

In one example, the number average molecular weight (Mn) of the block copolymer (B) may exceed 200,000. More specifically, the block copolymer (B) may have a number average molecular weight of 210,000 or more, 220,000 or more, 230,000 or more, 240,000 or more, 250,000 or more, or 260,000 or more, and 500,000 or less, 450,000 or less, 400,000 or less, 350,000 or less, or It may have a number average molecular weight of 300,000 or less.

In one example, the number average molecular weight of the first block may be in the range of 2,500 to 100,000. Specifically, the number average molecular weight of the block 1B may be 10,000 or more, 15,000 or more, 20,000 or more, 25,000 or more, 30,000 or more, 35,000 or more, 40,000 or more, 45,000 or more, or 50,000 or more, and 90,000 or less, 85,000 or less, 80,000 or less. , 75,000 or less, 70,000 or less, 65,000 or less, 60,000 or less, or 55,000 or less.

When a block copolymer (A) and a block copolymer (B) satisfying the number average molecular weight are used together, it is advantageous in securing step-overcoming properties without reducing the durability of the adhesive layer, and excellent interfacial adhesion, peeling You can secure the power and fairness of the foundation.

In one example, the ratio of the weight average molecular weight (Mw) and number average molecular weight (Mn) of the block copolymer (A) (Mw/Mn), that is, the molecular weight distribution (PDI=Mw/Mn), is in the range of 1.0 to 4.0 Can be More specifically, the lower limit of the PDI value of the block copolymer (A) is 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, 2.0 or more, 2.1 or more, 2.2 It may be more than, 2.3 or more, 2.4 or more, 2.5 or more, 2.6 or more, 2.7 or more, or 2.8 or more. And the upper limit is 3.9 or less, 3.8 or less, 3.7 or less, 3.6 or less, 3.5 or less, 3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, 3.0 or less, 2.9 or less, 2.8 or less, 2.7 or less, 2.6 or less, 2.5 or less, or May be less than or equal to 2.4.

In one example, the molecular weight distribution (PDI) of the 1A block may be in the range of 1.0 to 2.5. Specifically, the molecular weight distribution (PDI) of the block 1A is 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, or 1.5 or more, 2.4 or less, 2.3 or less, 2.2 or less, 2.1 or less, 2.0 or less, 1.9 or less, 1.8 or less Or 1.7 or less.

In one example, the molecular weight distribution (PDI) of the block copolymer (B) may range from 1.5 to 4.0. More specifically, the lower limit of the PDI value of the block copolymer (A) may be 1.6 or more, 1.7 or more, 1.8 or more, 1.9 or more, 2.0 or more, 2.1 or more, 2.2 or more, 2.3 or more, 2.4 or more, 2.5 or more, or 2.6 or more. . And the upper limit may be 3.5 or less, 3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, 3.0 or less, 2.9 or less, or 2.8 or less.

In one example, the molecular weight distribution (PDI) of the 1B block may be in the range of 1.0 to 2.5. Specifically, the molecular weight distribution (PDI) of the first block is 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, or 1.5 or more, and is 2.4 or less, 2.3 or less, 2.2 or less, 2.1 or less, 2.0 or less, 1.9 or less, 1.8 or less Or 1.7 or less.

When the molecular weight distribution is satisfied, it may be more advantageous in improving durability, step recovery, interfacial adhesion, peeling force, and cutting processability.

As mentioned above, each of the block copolymer (A) and the block copolymer (B) may include at least two or more blocks having different glass transition temperatures. In the present application, the "glass transition temperature of the block" constituting the block copolymer may be calculated according to the method described in the following examples.

In one example, the block copolymer (A) is a 1A block having a glass transition temperature of 20 °C or higher; And a second block having a glass transition temperature of -10° C. or less.

In one example, the block 1A may be at least 20°C, at least 25°C, at least 30°C, at least 35°C, at least 40°C, or at least 45°C. And, although not particularly limited, the upper limit of the 1A block glass transition temperature may be 70 ℃ or less, 65 ℃ or less, or 60 ℃ or less.

In one example, the second block may be -15°C or less, -25°C or less, -30°C or less, -35°C or less, -40°C or less, -45°C or less, or -50°C or less. In addition, the lower limit of the 2A block glass transition temperature is not particularly limited, but may be, for example, -80°C or higher, -70°C or higher, or -60°C or higher.

In the present application, the block copolymer (A) that satisfies the glass transition temperature can impart advantageous properties to the pressure-sensitive adhesive for overcoming the step. When the first block satisfies the glass transition temperature in the above range, an autoclave ( It can be advantageous in absorbing the step difference without bleeding or steaming under the compression condition of autoclave). In addition, when the 2A block satisfies the glass transition temperature range, it may contribute to increase the adhesion.

In one example, the block copolymer (B) is a 1B block having a glass transition temperature of 20 °C or higher; And a 2B block having a glass transition temperature of -10 °C or less.

In one example, the block 1B is 20 ℃ or more, 25 ℃ or more, 30 ℃ or more, 35 ℃ or more, 40 ℃ or more, 45 ℃ or more, 50 ℃ or more, 55 ℃ or more, 60 ℃ or more, 65 ℃ or more, It may be 70 ℃ or more, 75 ℃ or more, or 80 ℃ or more. In addition, although not particularly limited, the upper limit of the 1B block glass transition temperature may be 150°C or less, 140°C or less, 130°C or less, 120°C or less, or 110°C or less.

In one example, the second block may be -15°C or less, -25°C or less, -30°C or less, -35°C or less, -40°C or less, or -45°C or less. In addition, the lower limit of the 2B block glass transition temperature is not particularly limited, but may be, for example, -80°C or higher, -70°C or higher, -60°C or higher, or -50°C or higher.

In the present application, the block copolymer (B) that satisfies the glass transition temperature may impart durability and adhesion to the pressure-sensitive adhesive. Specifically, the first block 1B may impart durability to the pressure-sensitive adhesive, and the second block 2A may contribute to increasing adhesion.

In one example, the glass transition temperature of the hard segment of the block copolymer (B) may be higher than the glass transition temperature of the hard segment of the block copolymer (A). That is, the glass transition temperature of the first block may be higher than that of the first block. For example, the glass transition temperature of the block copolymer (A) 1A block may be 60°C or less or 50°C or less, specifically 30 to 60°C or 30 to 50°C, and the block copolymer (B ) The glass transition temperature of the 1B block may be 50°C or higher (or over 50°C) or 60°C or higher (or over 60°C). For example, the glass transition temperature of the block copolymer (B) 1B block may be 65°C or higher, 70°C or higher, 75°C or higher, or 80°C or higher. When the glass transition temperature relationship between the block copolymer hard blocks is satisfied as described above, the chain of the block 1A is released under the autoclave compression conditions (about 50 ℃) for bonding the adhesive film, thereby physically removing the space due to the step difference. It can be filled with, and at the same time, the 1B block can prevent side effects such as excessively low modulus of the adhesive film even at high temperatures. That is, when the glass transition temperature relationship between the block copolymer hard blocks is satisfied as described above, the block 1B of the block copolymer (B) provides durability through a high glass transition temperature, and at the same time, the glass transition temperature is relatively The 1A block of the low block copolymer (A) can efficiently absorb the step difference under the compression conditions of an autoclave related to film production.

Although not particularly limited, when considering manufacturing efficiency, step absorption ability, cutting properties, high temperature and/or high humidity durability, the block copolymer is advantageously a diblock copolymer or a triblock copolymer.

In one example, the block copolymer (A) may include 5 to 95 parts by weight of the 1A block and 5 to 95 parts by weight of the 2A block. In the present application, "part by weight" may mean a weight ratio between each component. For example, configuration (a) 20 parts by weight to 100 parts by weight and configuration (b) 0 parts by weight to 80 parts by weight are included, the ratio based on the weight of the configuration (a) and the configuration (b) is 20 to 100: It may mean the case of 0 to 80.

In one example, the block copolymer (A) may include a soft segment in an amount equal to or higher than the content of the hard segment. For example, the block copolymer (A) may include 5 to 50 parts by weight of the 1A block and 50 to 95 parts by weight of the 2A block.

In one example, the block copolymer (A) may contain an excess of soft segments. Specifically, the block copolymer (A) may include 5 to 45 parts by weight of the 1A block and 55 to 95 parts by weight of the 2A block. More specifically, within the above range, the block copolymer (A) is 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, or 40 parts by weight More than 1A block may be included, and 90 parts by weight or less, 85 parts by weight or less, 80 parts by weight or less, 75 parts by weight or less, 70 parts by weight or less, 65 parts by weight or less, or 60 parts by weight or less. Can include.

When the content ratio between the 1A block and the 2A block included in the block copolymer is satisfied, excellent cutting processability and durability, as well as step absorption properties may be secured.

In one example, the block copolymer (B) may include 5 to 95 parts by weight of the 1B block and 5 to 95 parts by weight of the 2B block.

In one example, the block copolymer (B) may include a soft segment in an amount equal to or higher than the content of the hard segment. For example, the block copolymer (B) may include 5 to 50 parts by weight of the 1B block and 50 to 95 parts by weight of the 2B block.

In one example, the block copolymer (B) may contain an excess of soft segments. For example, the block copolymer (B) may include 5 to 45 parts by weight of the 1B block and 55 to 95 parts by weight of the 2B block. Specifically, the block copolymer (B) may include 5 to 35 parts by weight of the 1B block and 65 to 95 parts by weight of the 2B block. More specifically, within the above range, the block copolymer (B) is 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight or more, 11 parts by weight or more, 12 parts by weight Or more, 13 parts by weight or more, 14 parts by weight or more, 15 parts by weight or more, 16 parts by weight or more, 17 parts by weight or more, 18 parts by weight or more, 19 parts by weight or more, or 20 parts by weight or more of the 1B block, And 94 parts by weight or less, 93 parts by weight or less, 92 parts by weight or less, 91 parts by weight or less, 90 parts by weight or less, 89 parts by weight or less, 88 parts by weight or less, 87 parts by weight or less, 86 parts by weight or less, 85 parts by weight or less , 84 parts by weight or less, 83 parts by weight or less, 82 parts by weight or less, 81 parts by weight or less, or 80 parts by weight or less of the 2B block may be included.

When the content ratio is satisfied, it is possible to ensure excellent cutting processability and durability, as well as step absorption properties.

In one example, the pressure-sensitive adhesive composition may include the block copolymer (B) in an amount equal to or higher than the content of the block copolymer (A). For example, the content ratio between the copolymers in the pressure-sensitive adhesive composition, that is, the block copolymer (A): the block copolymer (B) may be 10 to 50 parts by weight: 50 to 90 parts by weight.

In one example, the pressure-sensitive adhesive composition may include the block copolymer (B) in an excess amount than the block copolymer (A). Specifically, within the above range, the pressure-sensitive adhesive composition contains 85 parts by weight or less, 80 parts by weight or less, 75 parts by weight or less, 70 parts by weight or less, 65 parts by weight or less, 60 parts by weight or less of the block copolymer (B), or It may contain 55 parts by weight or less, and 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, 40 parts by weight or more, or 45 parts by weight of the block copolymer (A) May contain more than one part.

When the adhesive layer includes a high molecular weight crosslinkable block copolymer (B) and a low molecular weight non-crosslinkable block copolymer (A) in the above amount, it is possible to overcome a step difference and at the same time secure excellent durability.

As mentioned above, in the present application, a crosslinkable block copolymer and a non-crosslinkable block copolymer may be used at the same time. Specifically, the block copolymer (A) having a low molecular weight may be a non-crosslinkable copolymer that does not contain a crosslinkable functional group in its main chain or side chain, and the block copolymer (B) having a relatively high molecular weight includes a crosslinkable functional group. It may be a crosslinkable copolymer.

In this regard, the block copolymer (B) may contain a polymerized unit derived from a compound capable of providing a crosslinkable functional group in a block having a predetermined glass transition temperature. In the present application, the term "polymerization unit" may mean a state in which the predetermined monomer is polymerized and contained in a resin, a polymer, or a main chain or side chain of a polymerization reactant formed by polymerization of a predetermined monomer.

The kind of the crosslinkable functional group is not particularly limited. For example, a hydroxy group, a carboxyl group, an epoxy group, an isocyanate group or a nitrogen-containing functional group can be used. If such a crosslinkable functional group can be provided to the first block and/or the second block, the specific type of the crosslinkable compound is also not particularly limited. For example, hydroxy group-containing monomers such as hydroxy group alkyl (meth)acrylate or hydroxy alkylene glycol (meth)acrylate; (Meth)acrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxypropylic acid, 4-(meth)acryloyloxy butyric acid, acrylic acid duplex, itaconic acid, maleic acid and Carboxyl group-containing monomers such as maleic anhydride; Alternatively, nitrogen-containing monomers such as (meth)acrylamide, N-vinyl pyrrolidone or N-vinyl caprolactam may be used alone or in combination of two or more.

In one example, the block copolymer (B) may include a crosslinkable functional group in the 2B block. That is, the block copolymer (B) may include a crosslinkable functional group in the soft segment. In this case, it is possible to control the crosslinking density in the soft segment of the block copolymer (B), which contributes to securing durability, and to impart appropriate cohesive strength and durability to the pressure-sensitive adhesive.

In one example, the block copolymer (B) may include a crosslinkable functional group only in the 2B block. That is, the block copolymer (B) may not include a crosslinkable functional group in the 1B block, which is a hard segment. In this case, since the first B block has a physical crosslinking structure, it is possible to provide a hard cohesive force such that high modulus can be secured at room temperature. In addition, in the high temperature condition in which the physical bond is partially released, the modulus is lowered while fluidity is generated in the hard domain chain, effectively alleviating the stress caused by the shrinkage of the components included in the adhesive article, and preventing the bending of the adhesive article or its configuration. Can be effectively suppressed. In order to function at a high temperature as described above, crosslinking of the hard block is unnecessary.

As long as the molecular weight and the glass transition temperature are satisfied, the types of monomers for forming each block copolymer are not particularly limited. For example, the block copolymer (A) and/or the block copolymer (B) may include a polymerization unit derived from a (meth)acrylic acid ester.

In one example, the hard segment of each block copolymer may include a polymerization unit derived from a (meth)acrylic acid ester. As the (meth)acrylic acid ester used for forming the hard segment, for example, alkyl (meth) acrylate may be used. In consideration of cohesion, glass transition temperature, and adhesion control, an alkyl (meth)acrylate having an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms may be used. have. Examples of such monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate )Acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-octyl (meth)acrylate, iso Bornyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate and lauryl (meth) acrylate, etc., and one or more of the above has the glass transition temperature You can choose and use it as much as possible.

In one example, when considering the glass transition temperature, when forming the hard segment (first block 1A or block 1B) of each block copolymer, methyl (meth)acrylate, butyl (meth)acrylate, and ethylhexyl ( Alkyl(meth)acrylates such as meth)acrylate can be used. More specifically, alkyl methacrylate may be used when forming the hard segment of each block copolymer to be advantageous in securing a high glass transition temperature.

In one example, the 1A block and/or the 1B block may be formed of only the alkyl (meth)acrylate monomer. In another example, the 1A block or 1B block may include a polymerization unit derived from 20 parts by weight to 100 parts by weight of an alkyl (meth)acrylate monomer and a polymerization unit derived from 0 to 80 parts by weight of other monomers. . At this time, other monomers are monomers other than the above-mentioned alkyl (meth)acrylate, and a monomer capable of providing a crosslinkable functional group or an aromatic functional group in each block, or a glass transition temperature of an appropriate level specified in this application. It may mean a monomer used to secure.

In one example, the soft segment of each block copolymer may include a polymerization unit derived from a (meth)acrylic acid ester. Specifically, in consideration of the glass transition temperature in the above-described range, a soft segment may be formed by using one or more monomers in an appropriate content range among the (meth)acrylic acid ester-based monomers listed above.

In one example, when considering the glass transition temperature, when forming the soft segment (the 2A block or the 2B block) of each block copolymer, for example, methyl (meth) acrylate, butyl (meth) acrylate And alkyl (meth)acrylates such as ethylhexyl (meth)acrylate may be used. More specifically, the alkyl acrylate may be used when forming the soft segment of each block copolymer so as to be advantageous in securing a relatively low glass transition temperature.

In one example, the 2A block and/or the 2B block may be formed of only the alkyl (meth) acrylate monomer. Alternatively, the 2A block or the 2B block may include a polymerization unit derived from 20 parts by weight to 100 parts by weight of the alkyl (meth)acrylate monomer and a polymerization unit derived from 0 to 80 parts by weight of other monomers.

In one example, the 2B block of the block copolymer (B) may contain 20 parts by weight or less of a polymerization unit derived from a compound capable of providing a crosslinkable functional group. For example, the 2B block of the block copolymer (B) may contain 15 parts by weight or less, 10 parts by weight or less, or 5 parts by weight or less of a polymerization unit derived from a compound capable of providing a crosslinkable functional group. The lower limit of the content of the polymerized unit derived from the compound is not particularly limited, but may be, for example, 0.1 parts by weight or more, 0.5 parts by weight or more, 1 part by weight or more, or 1.5 parts by weight or more.

The type of the compound capable of providing the crosslinkable functional group used to form the crosslinkable block copolymer (B) is not particularly limited, but in one example, the compound capable of providing the crosslinkable functional group is a compound having a hydroxy group Can be

In one example, when the compound capable of providing the crosslinkable functional group has a hydroxy group, the high molecular weight crosslinkable block copolymer (B) may include a polymerization unit derived from the compound of Formula 1 below. The following compound of Formula 1 may provide a crosslinkable functional group to the 2B block of the block copolymer (B).

[Formula 1]

However, in Formula 1, Q is hydrogen or an alkyl group, A and B are each independently an alkylene group or an alkylidene group, and n is an integer within the range of 0 to 10. In addition, when there are two or more [-O-B-] units in Formula 1, the number of carbon atoms of B in each [-O-B-] unit may be the same or different.

In the present specification, the term alkyl group refers to a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, unless otherwise specified. It may be, and the alkyl group may be optionally substituted with one or more substituents. As the alkyl group in Formula 1, a straight or branched alkyl group having 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms may be exemplified. Although not particularly limited, when Q in Formula 1 is an alkyl group, Q may be an alkyl group having 1 to 4 carbon atoms.

In the present specification, the term alkylene group or alkylidene group is a linear, branched or ring having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms unless otherwise specified. It may mean an alkylene group or an alkylidene group, and the above may be optionally substituted by one or more substituents. Although not particularly limited, in Formula 1, for example, A and B may each independently be a linear alkylene group having 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms.

In addition, n in Formula 1 may be, for example, 0 to 7, 0 to 5, 0 to 3, or 0 to 2.

Examples of the compound of Formula 1 include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate. ) Acrylate and hydroxyalkyl (meth)acrylates such as 8-hydroxyoctyl (meth)acrylate. Or 2-hydroxyethylene glycol (meth)acrylate or 2-hydroxypropylene glycol (meth)acrylate may be exemplified by the compound of Formula 1 above. However, it is not particularly limited to the compounds listed above. Considering the glass transition temperature, securing appropriate durability by forming a crosslinked structure, etc., it may be preferable to use hydroxyethyl (meth)acrylate, and/or 4-hydroxybutyl (meth)acrylate.

In one example, the block copolymer (A) and/or the block copolymer (B) may include a polymerization unit derived from a monomer represented by Formula 2 below. Since the monomer represented by the following formula contains an alkylene oxide group represented by [-U-O-] and has a polarity, advantageous conditions for forming a block copolymer using a catalyst can be provided.

[Formula 2]

In Formula 2, Q is hydrogen or an alkyl group, U is an alkylene having 1 to 4 carbon atoms, m is a number within the range of 1 to 15, and Z is hydrogen, an alkyl group or an aryl group. In addition, when there are two or more [-U-O-] units in Formula 1, the number of carbon atoms of U in the unit may be the same or different.

In Formula 2, m may be an arbitrary number, for example, within the range of 1 to 15, within the range of 1 to 13, or within the range of 1 to 11. When the above range is satisfied, appropriate conductivity can be imparted to the pressure-sensitive adhesive.

In relation to Formula 2, the term alkyl group may mean an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, unless otherwise specified. The alkyl group may be linear, branched or cyclic. The alkyl group may be substituted by one or more substituents, or may be unsubstituted.

The term alkylene group in relation to Formula 2 may be an alkylene group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, unless otherwise specified. The alkylene group may be linear, branched or cyclic. If necessary, the alkylene group may be substituted with one or more substituents.

In relation to Formula 2, the term aryl group includes a benzene ring, or two or more benzene rings are linked, or two or more benzene rings share one or two or more carbon atoms, unless otherwise specified. It may mean a monovalent residue derived from a compound containing a condensed or bonded structure or a derivative thereof. The aryl group may be, for example, an aryl group having 6 to 25 carbon atoms, 6 to 22 carbon atoms, 6 to 16 carbon atoms, or 6 to 13 carbon atoms. Examples of such aryl groups include phenyl group, phenylethyl group, phenylpropyl group, benzyl group, tolyl group, xylyl group or naphthyl group.

As the compound of Formula 2, for example, ethoxyethoxyethyl acrylate, alkoxy dialkylene glycol (meth)acrylic acid ester, alkoxy trialkylene glycol (meth)acrylic acid ester, alkoxy tetraalkylene glycol (meth)acrylic acid Ester, aryloxy dialkylene glycol (meth) acrylic acid ester, aryloxy trialkylene glycol (meth) acrylic acid ester, aryloxy tetraalkylene glycol (meth) acrylic acid ester or polyalkylene glycol mono (alkyl) ether (meth) Acrylic acid esters, and the like, but are not limited thereto.

As long as the properties such as the molecular weight and glass transition temperature of each block copolymer are not impaired, the hard segment of each block copolymer, that is, the 1A block and/or the 1B block, contains 35 weight of the polymerized unit derived from the compound of Formula 2 It may contain less than part. For example, the block 1A of the block copolymer (A) may contain 30 parts by weight or less, 25 parts by weight or less, or 20 parts by weight or less of the polymerization unit derived from the compound of Formula 2. The lower limit of the content of the polymerization unit derived from the compound of Formula 2 is not particularly limited, but may be, for example, 5 parts by weight or 10 parts by weight.

In one example, each of the block copolymers may further include a unit derived from an arbitrary copolymerizable monomer in a soft block or a hard block according to the need for securing a glass transition temperature. As the comonomer, (meth)acrylonitrile, (meth)acrylamide, N-methyl (meth)acrylamide, N-butoxy methyl (meth)acrylamide, N-vinyl pyrrolidone or N-vinyl capro Nitrogen-containing monomers such as lactam; Alkoxy alkylene glycol (meth) acrylic acid ester, alkoxy dialkylene glycol (meth) acrylic acid ester, alkoxy trialkylene glycol (meth) acrylic acid ester, alkoxy tetraalkylene glycol (meth) acrylic acid ester, alkoxy polyethylene glycol (meth) acrylic acid Ester, phenoxy alkylene glycol (meth) acrylic acid ester, phenoxy dialkylene glycol (meth) acrylic acid ester, phenoxy trialkylene glycol (meth) acrylic acid ester, phenoxy tetraalkylene glycol (meth) acrylic acid ester or phenoxy Alkylene oxide group-containing monomers such as polyalkylene glycol (meth)acrylic acid ester; Styrene-based monomers such as styrene or methyl styrene; Glycidyl group-containing monomers such as glycidyl (meth)acrylate; Carboxylic acid vinyl esters such as vinyl acetate; Or a monomer such as tetrahydrofuryl (meth) acrylate, but is not limited thereto. These comonomers may be included in the polymer by selecting one or more types of appropriate types as necessary. Such a comonomer-derived polymerization unit may be included in, for example, 20 parts by weight or less, or 0.1 to 15 parts by weight in each block.

A method of preparing the block copolymer is not particularly limited, and a known method may be used. For example, the block polymer may be polymerized in a LRP (Living Radical Polymerization) method. Specifically, an anionic polymerization method in which an organic rare earth metal complex is used as a polymerization initiator or an organic alkali metal compound is used as a polymerization initiator in the presence of an inorganic acid salt such as an alkali metal or alkaline earth metal salt, or an organic alkali metal compound is polymerized. Anionic polymerization method that is used as an initiator and synthesized in the presence of an organic aluminum compound, atomic transfer radical polymerization method (ATRP) using an atom transfer radical polymerization agent as a polymerization control agent, and an atom transfer radical polymerization agent as a polymerization control agent. ARGET (Activators Regenerated by Electron Transfer) atom transfer radical polymerization (ATRP), ICAR (Initiators for continuous activator regeneration) atom transfer radical polymerization (ATRP), reversible addition of inorganic reducing agents- Polymerization by reversible addition-cleavage chain transfer using a cleavage chain transfer agent (RAFT), or a method using an organic tellurium compound as an initiator may be used, and an appropriate method is selected from the above methods to prepare the block copolymer. I can.

The pressure-sensitive adhesive composition may be formed from an adhesive composition comprising at least one crosslinking agent capable of forming a chemical crosslinking structure by reacting with a crosslinkable functional group of the block copolymer. Non-limiting examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, or a metal chelate crosslinking agent.

In one example, when the crosslinkable functional group is a hydroxy group, an isocyanate crosslinking agent may be used. Specifically, an isocyanate crosslinking agent having at least two functional groups capable of reacting with the crosslinkable functional group of the block copolymer may be used. Examples of such isocyanate crosslinking agents include diisocyanate compounds such as tolyene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoborone diisocyanate, tetramethylxylene diisocyanate or naphthalene diisocyanate; Alternatively, a compound obtained by reacting the diisocyanate compound with a polyol; can be used. Trimethylol propane may be used as the polyol.

In one example, the crosslinking agent may be used in an amount of 0.01 parts by weight to 20 parts by weight based on 100 parts by weight of the block copolymer. More specifically, the lower limit of the content of the crosslinking agent may be 0.05 parts by weight or more or 0.10 parts by weight or more, and the upper limit may be 10 parts by weight or 5 parts by weight or less. In the content range of the crosslinking agent, the degree of crosslinking of the block copolymer may be appropriately adjusted, and through this, the cohesive strength, adhesive strength, and high temperature durability of the pressure-sensitive adhesive can be excellently maintained.

In one example, the pressure-sensitive adhesive composition may further include a silane coupling agent. As the silane coupling agent, for example, a silane coupling agent having a beta-cyano group or an acetoacetyl group can be used. Such a silane coupling agent may impart excellent adhesion and adhesion stability to the pressure-sensitive adhesive, and may impart durability reliability under high temperature and high humidity conditions.

As the silane coupling agent having a beta-cyano group or an acetoacetyl group, for example, a compound represented by the following formula 3 or 4 may be used.

[Formula 3]

(R ₅ ) _n Si(R ₆ ) _(4-n)

[Formula 4]

(R ₇ ) _n Si(R ₆ ) _(4-n)

In Formula 3 and/or 4, R5 is a beta-cyanoacetyl group or a beta-cyanoacetylalkyl group, R7 is an acetoacetyl group or an acetoacetylalkyl group, R6 is an alkoxy group, and n is of 1 to 3 It's a number.

At this time, in Formulas 3 and 4, the alkoxy group may be an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, and such an alkoxy group may be a linear, branched or ring It can be a prize.

In addition, n in Formulas 3 and 4 may be, for example, 1 to 3, 1 to 2, or 1.

Compounds corresponding to Formulas 3 and 4 include, for example, acetoacetylpropyl trimethoxy silane, acetoacetylpropyl triethoxy silane, beta-cyanoacetylpropyl trimethoxy silane, or beta-cyanoacetylpropyl trie. Examples include oxysilane, but are not limited thereto.

In one example, the adhesive composition may include 0.01 to 5 parts by weight or 0.01 to 1 parts by weight of a silane coupling agent based on 100 parts by weight of the block copolymer. Within this range, the desired physical properties can be effectively imparted to the pressure-sensitive adhesive.

The adhesive composition may further contain a tackifier, if necessary. As the tackifier, for example, a hydrocarbon resin or a hydrogenated product thereof, a rosin resin or a hydrogenated product thereof, a rosin ester resin or a hydrogenated product thereof, a terpene resin or a hydrogenated product thereof, a terpene phenol resin or a hydrogenated product thereof, a polymerized rosin resin or One kind or a mixture of two or more kinds, such as a polymerized rosin ester resin, may be used, but is not limited thereto. The tackifier may be included in the adhesive composition in an amount of 100 parts by weight or less based on 100 parts by weight of the block copolymer.

In addition, the adhesive composition may further include additives such as an epoxy resin, a curing agent, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, an antifoaming agent, a surfactant, or a plasticizer. The specific type or content of the additive is not particularly limited.

In another example related to the present application, the present application relates to an adhesive article comprising an adhesive layer. For example, as described below, the adhesive article includes a touch sensor, a display panel and/or a polarizing plate, and may be referred to as an optical device or an electronic device. In this case, the adhesive article may have a step. For example, the adhesive article may have a step in a portion of the article that the adhesive layer contacts. The cause of the formation of the step is not particularly limited, and the step may be formed, for example, to secure a predetermined function of the article or to secure a sense of beauty.

The pressure-sensitive adhesive layer is formed from the pressure-sensitive adhesive composition of the above-described configuration, and is optically transparent. For example, the adhesive layer may have a transmittance of 80% or more or 85% or more for a wavelength range of 380 to 780 nm.

The adhesive layer may have a thickness of 5 μm or more. Specifically, the adhesive layer may have a thickness of 10 µm or more, 15 µm or more, 20 µm or more, 25 µm or more, 30 µm or more, 35 µm or more, 40 µm or more, 45 µm or more, or 50 µm or more.

In one example, the adhesive layer may have a thickness greater than a step that the adhesive layer must absorb. Regarding the specific use of the adhesive article described below, considering that the thickness of the step is within the range of 20 to 50 μm, the thickness of the adhesive layer is, for example, 30 μm or more, 35 μm or more, 40 μm or more, 45 It may be µm or more, 50 µm or more, 55 µm or more, 60 µm or more, 65 µm or more, 70 µm or more, 75 µm or more, 80 µm or more, 85 µm or more, or 90 µm or more. In this case, the upper limit of the thickness is not particularly limited, but may be, for example, 120 µm or less, 110 µm or less, or 100 µm or less.

In one example, the adhesive layer may satisfy 35% or more of a reduction rate of modulus calculated as follows. When the reduction rate satisfies 35% or more, it means that the modulus decreases enough to overcome the step difference.

Modulus reduction rate = 100-{(100 x M ₂ )/M ₁ }

M ₁ is the modulus measured at room temperature (about 25 °C), M ₂ is the modulus measured at 50 °C and 5 atm, and each modulus is 5% strain and 1 rad/ s It can be measured under angular frequency conditions. At this time, the conditions of 50° C. and 5 atm are process conditions that simulate a pressing process for an adhesive layer made in an autoclave at the time of manufacturing an adhesive product having a step.

In one example, the reduction rate may be less than 45%. When the reduction rate is 45% or more, that is, the decrease in the modulus at 50° C. is too large, it may mean that it is difficult to secure durability even though the step overcomeability may be good. As can be seen from the following experimental results, fine adjustment of the adhesive layer modulus is required to secure durability and step overcoming properties at the same time.In the case of having the adhesive composition or the adhesive layer configuration according to the present application, both durability and step overcoming properties I can be satisfied.

In one example, the adhesive article may be a touch sensor. The touch sensor refers to a device capable of recognizing input information obtained through contact with a user, and may be a sensor known in the related art. For example, the touch sensor may include a capacitive sensor for recognizing a touch based on static electricity generated in a user's body contact part (eg, hand) and a change in current due thereto; A pressure-sensitive sensor for recognizing a touch based on a change in capacitance generated when the upper and lower conductive layers of the touch sensor are in contact with each other by a pressure applied by a user; Alternatively, it may be an optical touch sensor that recognizes a touch by recognizing scattering or total reflection of light caused by user contact. The configuration of a sensor capable of recognizing user contact in each method may be known in the related art.

In one example, the touch sensor may have a structure as shown in FIG. 1. That is, the touch sensor includes two opposing substrates, a printed circuit board positioned between the opposing substrates and having a step difference; And an adhesive layer disposed between the opposite substrates and absorbing the step difference.

In one example, at least one of the opposite substrates may be a conductive layer having electrical conductivity.

The specific configuration of the conductive layer is not particularly limited. For example, the conductive layer is ITO (Indium Tin Oxide), In ₂ O ₃ (indium oxide), IGO (indium galium oxide), FTO (Fluor doped Tin Oxide), AZO (Aluminium doped Zinc Oxide), GZO (Galium Doped Zinc Oxide), ATO (Antimony doped Tin Oxide), IZO (Indium doped Zinc Oxide), NTO (Niobium doped Titanium Oxide), ZnO (zink oxide), or CTO (Cesium Tungsten Oxide). However, the material of the conductive layer is not limited to the materials listed above.

In one example, the conductive layer may be a conductive film on which an X-axis pattern electrode and/or a Y-axis pattern electrode is formed. In the transparent conductive film, the pattern may be formed in an appropriate shape and position by a person skilled in the art related to the touch panel.

The printed circuit board (PCB) includes both a rigid printed circuit board or a flexible printed circuit board. The configuration of the printed circuit board is not particularly limited, and may have a known configuration of the printed circuit board used in the technical field related to the PCB. For example, the substrate is a substrate formed by laminating a metal foil on an insulating film and then etching it, and may have a pattern or the like by etching, and may have a step by the pattern as described above.

In one example, a control IC may be positioned on any one side or side of the printed circuit board. The control IC may be composed of, for example, a signal source, a multiplexer, an A/D converter, etc., converting an analog signal transmitted from a panel into a digital signal, and a touch area It may be a configuration in which data (coordinate values, etc.) necessary to determine the coordinates of is controlled and transmitted to a host (eg, a smartphone AP, etc.).

In another example, the adhesive article may be a touch panel. The touch panel may sequentially include a touch sensor having the above-described configuration, a second adhesive layer, and a cover glass, as shown in FIG. 2. The configuration of the second adhesive layer may be the same as that of the first adhesive layer described above. The touch sensor may also have the same configuration as described above.

In another example, the adhesive article may be an adhesive polarizer or a polarizing plate including a polarizer and an adhesive layer. In the case of the adhesive layer of the present application, since it can provide general durability and adhesive force required for a pressure-sensitive adhesive for a polarizing plate, as confirmed in the following experimental examples, in addition to the step-absorbing ability, it can be applied to an adhesive article such as an adhesive polarizer or a polarizing plate. The specific configuration of the polarizer or the polarizing plate is the same as described below.

In another example, the adhesive article may be a device including the adhesive polarizer or a polarizer and a display panel. The device may be, for example, a PDA, a mobile phone such as a smart phone, a tablet PC, or a mobile device such as a notebook. The specific configuration of the polarizer, the polarizing plate, and the display panel is the same as described below.

In another example, as in FIG. 3, the adhesive article may include a touch sensor or a touch panel described above; And a device including a display panel. The device may be, for example, a PDA, a mobile phone such as a smart phone, a tablet PC, or a mobile device such as a notebook. A touch panel or a touch sensor may have the same configuration as described above.

The display panel may include an LCD panel or an OLED panel, and a polarizing plate attached to one or both sides of the panel. In this case, the polarizing plate may be attached on the LCD or OLED panel using the adhesive layer having the same configuration as the adhesive layer described above.

In order to attach the polarizing plate to the LCD or OLED panel, the method of forming the pressure-sensitive adhesive layer on the polarizing plate is not particularly limited. For example, the adhesive composition is directly coated on a polarizing plate, etc., and then cured to realize a crosslinked structure, or the adhesive composition is coated and cured on the release-treated surface of a release film to form a crosslinked structure, and then transferred You can use such a method.

The method of coating the adhesive composition is not particularly limited, and for example, a method of applying the adhesive composition by a conventional means such as a bar coater may be used.

It is preferable from the viewpoint of performing a uniform coating process that the crosslinking agent contained in the adhesive composition is controlled so that the crosslinking reaction of the functional group does not proceed during the coating process, and through this, the crosslinking agent improves the crosslinking structure in the curing and aging process after the coating operation. By forming, it is possible to improve the cohesiveness of the pressure-sensitive adhesive, and improve adhesion properties and cuttability.

In addition, the coating process is preferably carried out after sufficiently removing bubbles-inducing components such as volatile components or reaction residues inside the adhesive composition, and accordingly, the crosslinking density or molecular weight of the adhesive is too low, so that the elastic modulus decreases, and in a high temperature state Bubbles existing between the glass plate and the adhesive layer become large, thereby preventing a problem of forming a scattering body inside.

After coating, a method of implementing a crosslinked structure by curing the adhesive composition is also not particularly limited. For example, the coating layer may be maintained at an appropriate temperature so that a crosslinking reaction between the block copolymer included in the coating layer and the multifunctional crosslinking agent may be induced.

The polarizing plate may include a polarizer. The type of polarizer is not particularly limited, and for example, a general type known in this field such as a polyvinyl alcohol polarizer may be employed without limitation.

The polarizer is a functional film capable of extracting only light vibrating in one direction from incident light while vibrating in various directions. Such a polarizer may be, for example, in a form in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. The polyvinyl alcohol-based resin constituting the polarizer can be obtained, for example, by gelling a polyvinyl acetate-based resin. In this case, the polyvinyl acetate-based resin that can be used may include a homopolymer of vinyl acetate, as well as a copolymer of vinyl acetate and other monomers copolymerizable therewith. Examples of the monomers copolymerizable with vinyl acetate may include one or more mixtures of unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and acrylamides having an ammonium group, but are limited thereto. no. The degree of gelation of the polyvinyl alcohol-based resin may be generally about 85 mol% to 100 mol%, and preferably 98 mol% or more. The polyvinyl alcohol-based resin may be further modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. In addition, the degree of polymerization of the polyvinyl alcohol-based resin may be generally about 1,000 to 10,000 or about 1,500 to 5,000.

The polarizer is a process of stretching a polyvinyl alcohol-based resin film as described above (ex.uniaxial stretching), a process of dyeing a polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, and the dichroic dye is adsorbed. The polyvinyl alcohol-based resin film can be prepared through a process of treating the resulting polyvinyl alcohol-based resin film with an aqueous boric acid solution and a process of washing with water after treatment with an aqueous boric acid solution. In the above, as the dichroic dye, iodine or a dichroic organic dye may be used.

In addition to the polarizer, the polarizing plate may include a protective film and/or an optical functional film.

In one example, the polarizing plate may include a protective film attached to one or both surfaces of the polarizer, and in this case, the pressure-sensitive adhesive layer may be formed on one or both surfaces of the protective film. In one example, the pressure-sensitive adhesive layer may be formed on a side opposite to the polarizer of the protective film. The type of the protective film is not particularly limited, for example, a cellulose-based film such as TAC (Triacetyl cellulose); Polyester-based films such as polycarbonate films or PET (poly(ethylene terephthalet)); Polyethersulfone film; Alternatively, a film having a single layer or a two or more layered structure, such as a polyethylene film, a polypropylene film, or a polyolefin-based film manufactured using a resin having a cyclo-based or norbornene structure, or an ethylene-propylene copolymer, may be used. When considering securing moisture barrier properties, PET-based and polyolefin-based films can be used, and when high-temperature durability is considered, an acrylic film can be used.

In one example, the polarizing plate may further include one or more optical functional films selected from the group consisting of a reflective film, an anti-glare film, a retardation film, a wide viewing angle compensation film, and a brightness enhancing film.

In one example, the polarizing plate may include at least one wide viewing angle compensation film selected from ±A film, ±B film, and ±C film. In the present application,'A film' refers to a film that satisfies the refractive index of the film nx ≠ny = nz. In this case, a case of nx> ny is referred to as a +A film, and a case of nx <ny is referred to as a -A film. . The'B film' refers to a film whose refractive index satisfies nx ≠ny ≠nz, where nx> ny> nz is referred to as -B film, and nz> nx> ny is referred to as +B film. The'C film' refers to a film in which the refractive index of the film satisfies nx = ny ≠nz. In this case, a case of ny <nz is referred to as a +C film, and a case of ny> nz is referred to as a -C film. In this regard, nx means the refractive index in the slow axis direction in the plane direction of the film or plate, ny means the refractive index in the direction perpendicular to the slow axis in the plane direction of the film or plate, and nz is the film Or it means the refractive index in the thickness direction of the plate.

In one example, the polarizing plate may include a retardation film. The retardation layer may be, for example, a quarter wave plate (QWP). The quarter wave plate may have a quarter wave phase delay characteristic. In the present specification, the term n-wavelength phase delay property refers to a property capable of retarding incident light by n times the wavelength of the incident light within at least a partial wavelength range. The quarter-wavelength phase delay characteristic may be a characteristic of converting incident linearly polarized light into elliptical polarized light or circularly polarized light, and conversely converting incident elliptical polarized light or circularly polarized light into linearly polarized light. As the quarter wave plate, a quarter wave plate generally manufactured and distributed in the related art field may be used. For example, a uniaxially stretched cycloolefin film, a uniaxially stretched polyethylene terephthalate film, a uniaxially stretched polycarbonate film, or a liquid crystal film may be used without limitation.

When the panel is a liquid crystal panel, the liquid crystal panel may include, for example, a first substrate sequentially formed, a pixel electrode, a first alignment layer, a liquid crystal layer, a second alignment layer, a common electrode, and a second substrate. In one example, the first and second substrates may be glass substrates. In this case, the polarizing plate or the optical laminate may be attached to the glass substrate via the pressure-sensitive adhesive layer described above.

The device may further include a light source on a side opposite to the viewing side of the liquid crystal panel. On the first substrate on the light source side, for example, an active driving circuit including a TFT (Thin Film Transistor) and wiring as a driving element electrically connected to a transparent pixel electrode may be formed. The pixel electrode may include, for example, Indium Tin Oxide (ITO), and may function as an electrode for each pixel. In addition, the first or second alignment layer may include, for example, a material such as polyimide, but is not limited thereto.

Examples of the liquid crystal panel in the apparatus include a passive matrix type panel such as a twisted nematic (TN) type, a super twisted nematic (STN) type, a ferroelectic (F) type, or a polymer dispersed (PD) type; An active matrix type panel such as a two terminal type or a three terminal type; Known panels, such as an IPS (In Plane Switching) panel and a vertical alignment (VA) panel, may all be applied.

Other configurations of the display device, for example, the type of upper and lower substrates such as a color filter substrate or an array substrate in a liquid crystal display device are not particularly limited, and configurations known in the art may be employed without limitation.

According to the present application, an adhesive film excellent in both durability and step absorption properties under high temperature and/or high humidity conditions may be provided. The adhesive film may be applied to a touch sensor, a touch panel, and a device including them. In addition, the adhesive film of the present application may provide improved cutting productivity, and may provide adhesion and durability required in a general adhesive for polarizing plates.

1 shows an example of an exemplary adhesive article according to an example of the present application. Specifically, FIG. 1 schematically shows a cross section of a touch sensor.
2 shows an example of an exemplary adhesive article according to an example of the present application. Specifically, FIG. 2 schematically shows a cross section of the touch panel.
3 shows an example of an exemplary adhesive article according to an example of the present application. Specifically, FIG. 2 schematically shows a cross section of a device including a touch sensor or a touch panel, and a display panel.
4 is a view for explaining the evaluation criteria of the step overcomeability measured in the present application examples and comparative examples.

Hereinafter, the present application will be described in detail through examples. However, the scope of protection of the present application is not limited by the examples described below.

Measurement or evaluation item

1. Molecular weight

The number average molecular weight (Mn) and molecular weight distribution (PDI) of the block copolymer were measured using GPC (Gel Permeation Chromatograph), and the GPC measurement conditions are as follows. The measurement results were converted using standard polystyrene (Aglient system (manufactured)) to prepare the calibration curve (Table 1).

<GPC measurement conditions>

Measuring instrument: Aglient GPC (Aglient 1200 series, U.S.)

Column: Connect 2 PL Mixed B

Column temperature: 40°C

Eluent: THF (Tetrahydrofuran)

Flow rate: 1.0 mL/min

Concentration: ~1mg/mL (100µl injection)

2. Durability

The adhesive polarizing plates prepared in Examples and Comparative Examples were cut to have a width of about 180 mm and a length of about 320 mm, and this was attached to a commercial liquid crystal panel of 19 inches. Thereafter, the panel to which the polarizing plate is attached is stored in an autoclave (50° C. 5 atm) for about 20 minutes to prepare a sample. After the sample was left at 65° C. and 95% relative humidity for 500 hours, the occurrence of bubbles and peeling at the adhesive interface was observed, and the moisture and heat resistance of the sample was evaluated according to the following criteria. In addition, after the sample was maintained at 100° C. for 500 hours, the occurrence of air bubbles and peeling was observed to evaluate heat resistance and durability according to the following criteria (Table 2).

<Moisture heat durability evaluation criteria>

A: No bubbles and peeling occurred

B: Some bubbles and/or peeling occurred

C: A large amount of bubbles and/or peeling occurs

<Heat resistance and durability evaluation criteria>

A: 0 bubbles

B: 1 to 10 bubble generation

C: 11 or more bubbles

3. Glass transition temperature

The glass transition temperature (Tg) of each block of the copolymer was calculated according to Equation A below.

<Equation A>

1/Tg=∑Wn/Tn

In the above formula, Wn is the weight fraction of the block copolymer or the monomer applied to each block of the copolymer, and Tn represents the glass transition temperature when each monomer forms a homopolymer. That is, in Equation A, the right side is the result of summing the calculated values after calculating all of the values (Wn/Tn) by dividing the weight fraction of the monomer used by the glass transition degree indicated when the monomer forms a homopolymer. Is (Table 1).

4. Peel force

Specimens were prepared by cutting the adhesive polarizing plates prepared in Examples and Comparative Examples to have a width of 25 mm and a length of 100 mm. Subsequently, the release PET film adhered to the pressure-sensitive adhesive layer is peeled off, and the pressure-sensitive adhesive polarizing plate is adhered to the soda lime glass using a 2 kg roller according to JIS Z 0237. A sample is prepared by compressing the glass to which the polarizing plate is attached for about 20 minutes in an autoclave (50°C, 5 atm), and storing it in a constant temperature and humidity condition (23°C, 50% relative humidity) for 24 hours. Thereafter, using a TA equipment (Texture Analyzer, manufactured by Stable Micro Systems Co., Ltd.), the polarizing plate was peeled from the glass at a peeling rate of 0.3 m/min and a peeling angle of 180 degrees to measure the peel force. (Table 2).

5. Interface adhesion

The adhesive polarizing plates prepared in Examples and Comparative Examples were cut to have a horizontal length of 50 mm and a vertical length of 100 mm to prepare a specimen. Thereafter, the adhesive surface of the specimen is attached to a tape with strong adhesive strength (American Tape), and then compressed using a 2 kg roller and left at room temperature for 10 minutes. Thereafter, the adhesive tape is removed from the adhesive layer, and the adhesive surface is separated from the polarizing plate interface and the area transferred to the tape is measured (Table 2).

<Evaluation criteria>

A: The residual area of the adhesive to the tape is less than 5%

B: 5% to 30% of the residual area of the pressure-sensitive adhesive tape

C: 30% or more of the residual area of the adhesive to the tape

6. Foundationality

When the polarizing plates prepared in Examples and Comparative Examples were cut with a cutter, the degree of sagging or escaping of the adhesive was observed with the naked eye and evaluated based on the following criteria (Table 2).

<Evaluation criteria>

A: No sagging and loosening of the adhesive was observed

B: Adhesive sagging and/or dropping was slightly observed

C: adhesive sagging and/or loosening is observed a lot

7. Step overcoming

A specimen was prepared by peeling off one release PET of an adhesive NCF (Non Carrier Film) product coated with a thickness of 70 um on a TAC film having a step of 50 μm with an acrylic epoxy adhesive, and laminating the adhesive side. Before and after leaving for 20 minutes in an autoclave condition of 50° C. and 5 atm, the separation distance of the adhesive generated at the step portion of the specimen was observed with an optical microscope, and the step overcomeability was evaluated according to the following evaluation criteria (Table 2).

<Evaluation criteria>

A: No excitation site was observed from the stepped interface (see Fig. 4A)

B: Part of the excitation from the step interface is less than 500 μm (see FIG. 4B)

C: 500 μm or more of the excitation site from the stepped interface (see FIG. 4C)

8. Modulus measurement

After laminating the NCF type adhesive coating to a thickness of 1 mm, a cylindrical sample with a diameter of 8 mm is prepared. Afterwards, the storage modulus of the adhesive is measured at room temperature (25°C) and 50°C (5 atm) using a modulus meter (ARES-G2). The strain applied to measure the modulus was 5%, and the value at the angular frequency 1 rad/s was measured. The conditions of 50° C. and 5 atmospheres simulate the pressing process performed in an autoclave when manufacturing an adhesive product having a step, and when pressed under the conditions, the pressure-sensitive adhesive can be filled with a gap in the step.

Preparation example of copolymer

Preparation Example 1: Preparation of diblock copolymer (A1)

0.87 g of ethyl 2-bromoisobutyrate (EBiB) and 178 g of methyl methacrylate (MMA) and 267 g of butyl methacrylate (BMA) were mixed with 292 g of ethyl acetate (EAc). The reactor containing the mixture was sealed, purged and stirred with nitrogen at about 25° C. for about 30 minutes, and dissolved oxygen was removed through bubbling. Thereafter, 0.065 g of CuBr2, 0.17 g of TPMA (tris(2-pyridylmethyl)amine) and 0.4 g of V-65 (2,2'-azobis(2,4-dimethyl valeronitrile)) were added to the mixture from which oxygen was removed. And immersed in a reaction tank at about 67°C to initiate the reaction (polymerization of the first block). When the conversion rate of methyl methacrylate was about 70%, 556 g of n-butyl acrylate (BA) previously bubbling with nitrogen was added and chain extension reaction was performed (polymerization of the second block. ). When the conversion ratio of the monomer (BA) reached 80% or more, the reaction mixture was exposed to oxygen and diluted in an appropriate solvent to terminate the reaction to prepare a block copolymer (V-65 in the above process considers its half-life. Then, it was appropriately divided and added until the reaction was completed.).

Preparation Example 2: Preparation of diblock copolymer (A2)

EBiB (ethyl 2-bromoisobutyrate) 0.87 g and methyl methacrylate (MMA) 356 g and commercially available polyethylene glycol monomethacrylate (PEGMA) (FM-401, ethylene oxide added mole number is 9 moles, terminated with a methyl group) 89 g Was mixed with 173 g of ethyl acetate (EAc). The reactor containing the mixture was sealed, purged and stirred with nitrogen at about 25° C. for about 30 minutes, and dissolved oxygen was removed through bubbling. Thereafter, 0.067 g of CuBr2, 0.18 g of TPMA (tris(2-pyridylmethyl)amine) and 0.4 g of V-65 (2,2'-azobis(2,4-dimethyl valeronitrile)) were added to the mixture from which oxygen was removed. And immersed in a reaction tank at about 67°C to initiate the reaction (polymerization of the first block). When the conversion rate of methyl methacrylate was about 70%, 556 g of n-butyl acrylate (BA) previously bubbling with nitrogen was added and chain extension reaction was performed (polymerization of the second block. ). When the conversion ratio of the monomer (BA) reached 80% or more, the reaction mixture was exposed to oxygen and diluted in an appropriate solvent to terminate the reaction to prepare a block copolymer (V-65 in the above process is It was appropriately divided and added until the reaction was completed.).

Preparation Example 3: Preparation of triblock copolymer (A3)

Bi-EBr (Ethylene bis(2-bromoisobutyrate)) 1.9 g, ethyl hexyl acrylate (EHA) 480 g, Tetrahydrofurfuryl acrylate (THFA) 131 g, methyl acrylate (MA) 131 g, and butyl acetate (BuAc) 223 g were mixed. The reactor containing the mixture was sealed, purged and stirred with nitrogen at about 25° C. for about 30 minutes, and dissolved oxygen was removed through bubbling. Thereafter, 0.04 g of CuBr2, 0.3 g of TPMA (tris(2-pyridylmethyl)amine) and 1.1 g of V-65 (2,2'-azobis(2,4-dimethyl valeronitrile)) were added to the mixture from which oxygen was removed. Then, the reaction was initiated by immersing in a reaction tank at about 73°C (polymerization of the second block). Ethyl hexyl methacrylate (EHMA) 187 g, methyl methacrylate (MMA) 120 g, styrene (Styrene) 36 g and butyl acetate (EHMA) previously bubbled with nitrogen at the time when the conversion rate of ethyl hexyl methacrylate is about 70% A mixture of 289 g of BuAc) was added in the presence of nitrogen. Thereafter, 0.4 g of V-65 was added to the reactor, and chain extension reaction was performed (polymerization of the first block). When the conversion rate of the monomer (EHA) reached 80% or more, the reaction mixture was exposed to oxygen and diluted in an appropriate solvent to terminate the reaction to prepare a block copolymer (V-65 in the above process considers its half-life. Then, it was appropriately divided and added until the reaction was completed.).

Preparation Example 4: Preparation of block copolymer (B1)

0.136 g of ethyl 2-bromoisobutyrate (EBiB) and 75.7 g of methyl methacrylate (MMA) and 32.4 g of butyl methacrylate (BMA) were mixed with 42 g of ethyl acetate (EAc). The reactor containing the mixture was sealed, purged and stirred with nitrogen at about 25° C. for about 30 minutes, and dissolved oxygen was removed through bubbling. Thereafter, 0.018 g of CuBr2, 0.046 g of TPMA (tris(2-pyridylmethyl)amine) 0876 g and 0.1 g of V-65 (2,2'-azobis(2,4-dimethyl valeronitrile)) were added to the mixture from which oxygen was removed. Then, the reaction was initiated by immersing in a reaction tank at about 67°C (polymerization of the first block). A mixture of 1076 g of n-butyl acrylate (BA), 16.4 g of hydroxybutyl acrylate (HBA) and 750 g of ethyl acetate (EAc), previously bubbled with nitrogen at the time when the conversion rate of methyl methacrylate is about 70% Was introduced in the presence of nitrogen. Thereafter, 0.04 g of CuBr2, 0.1 g of TPMA and 0.4 g of V-65 were added to the reactor, and a chain extension reaction was performed (polymerization of the second block). When the conversion ratio of the monomer (BA) reached 80% or more, the reaction mixture was exposed to oxygen and diluted in an appropriate solvent to terminate the reaction to prepare a block copolymer (V-65 in the above process is It was appropriately divided and added until the reaction was completed.).

[Table 1]

Manufacturing example 5: Of random copolymer (C1) Produce

A monomer mixture consisting of 97 parts by weight of n-butylacrylate (BA) and 3 parts by weight of hydroxybutyl acrylate (HBA) in a 1L reactor in which nitrogen gas is refluxed and a cooling device is installed to facilitate temperature control Was put in. Thereafter, 150 parts by weight of ethyl acetate (EAc) was added as a solvent. After purging nitrogen gas for about 60 minutes to remove oxygen, 0.09 parts by weight of AIBN (azobisisobutyronitrile) as a reaction initiator was added while maintaining the temperature at 60° C., and reacted for about 8 hours to allow a random copolymer (C1 ) Was prepared. The number average molecular weight of the prepared random copolymer was 400,000, the molecular weight distribution was 5.0, and the glass transition temperature was -48°C.

Examples and Comparative Examples

Example 1.

Preparation of coating solution (adhesive composition): TDI-based crosslinking agent (Coronate L, Japan NPU) based on 20 parts by weight of the block copolymer (A1) prepared in Preparation Example 1 and 80 parts by weight of the block copolymer (B1) prepared in Preparation Example 5 Article) 0.1 parts by weight, 0.01 parts by weight of DBTDL (Dibutyltin dilaurate), and 0.2 parts by weight of SCA were mixed, and ethyl acetate was added as a solvent to adjust the coating solid content to about 30% by weight to prepare a coating solution (adhesive composition).

(1) Preparation of adhesive polarizing plate: Pour the prepared coating liquid onto the release-treated surface of 38 μm-thick release PET (poly(ethylene terephthalate)) (MRF-38, Mitsubishi Corporation), and evenly apply the coating liquid using a doctor blade Then, it was dried in an oven at 80° C. for about 3 minutes to prepare a pressure-sensitive adhesive in the form of a 23 micron-thick film. Thereafter, a coating layer formed on the release PET was laminated on one side of a polarizing plate (stacked structure of COP/PVA/COP: COP=cyclopolyolefin, PVA=polyvinyl alcohol-based polarizing film) to prepare an adhesive polarizing plate.

(2) Manufacture of NCF (Non Carrier Film) adhesive coating : Pour the prepared coating solution onto the release treatment surface of 38 μm-thick release PET (poly(ethylene terephthalate)) (MRF-38, Mitsubishi Corporation), and use a doctor blade. The coating solution was evenly applied and dried in an oven at 80° C. for about 3 minutes to prepare a pressure-sensitive adhesive in the form of a film having a thickness of 70 micron. After drying, the release PET film was laminated on the adhesive surface to prepare an adhesive coating.

Examples 2 to 4 and Comparative Examples 1 to 6

When preparing the adhesive composition (coating solution), an adhesive composition (coating solution), an adhesive polarizing plate and an NCF product were prepared in the same manner as in Example 1, except that each component and ratio were adjusted as shown in Table 4 below.

[Table 2]

[Table 3]

As can be seen from Table 3, in order to satisfy high durability and cutting characteristics and at the same time effectively overcome the steps, as in the Example, a low molecular weight non-crosslinkable block copolymer (A) and a high molecular weight crosslinkable block copolymer (B It can be seen that) should be used in a certain content range at the same time.

Even if a low molecular weight polymer is used, if a high molecular weight crosslinkable block copolymer that provides durability is not used together, durability is not sufficient (Comparative Example 4), and a crosslinkable high molecular weight block polymer is used. Even in the case, when a polymer having a low molecular weight cannot be used, the step overcoming property is not good (Comparative Example 2). In addition, unlike the examples of the present application, Comparative Example 1, which does not satisfy the content ratio between block copolymers, has excellent characteristics related to overcoming the step, but has poor durability, and Comparative Example 3 using only random copolymers has durability and All of the step overcoming properties are not good.

Claims (17)

A non-crosslinkable block copolymer (A) comprising at least two blocks having different glass transition temperatures from each other; And
The block copolymer (A) and the number average molecular weight (Mn) are different, and the glass transition temperature includes a crosslinkable block copolymer (B) comprising at least two blocks different from each other,
It is formed from a pressure-sensitive adhesive composition containing an excess of the block copolymer (B) than the block copolymer (A),
An adhesive layer having a reduction rate of 35% or more in modulus calculated as follows:
Modulus reduction rate = 100-{(100 x M2)/M1}
(However, M1 is the modulus measured at room temperature, M2 is the modulus measured at 50°C, and each modulus is measured under the conditions of 5% strain and 1 rad/s angular frequency.) The method of claim 1, wherein the block copolymer (A) has a number average molecular weight (Mn) in the range of 50,000 to 200,000, and the block copolymer (B) has a number average molecular weight (Mn) than the block copolymer (A). This large adhesive layer. The adhesive layer according to claim 2, wherein the block copolymer (B) has a number average molecular weight (Mn) in the range of 100,000 to 500,000. The method of claim 1, wherein the block copolymer (A) comprises a first block having a glass transition temperature of 20° C. or higher; And a second A block having a glass transition temperature of -10° C. or less. The method of claim 4, wherein the block copolymer (B) comprises a first block having a glass transition temperature of 20 °C or higher; And a 2B block having a glass transition temperature of -10° C. or less. The adhesive layer according to claim 5, wherein the glass transition temperature of the block copolymer (B) 1B block is higher than the glass transition temperature of the block copolymer (A) block 1A. The adhesive layer according to claim 6, wherein the glass transition temperature of the block copolymer (A) 1A block is 60°C or less or 50°C or less. The adhesive layer according to claim 5, wherein the block copolymer (B) has a crosslinkable functional group in the 2B block, and the crosslinkable functional group is a hydroxy group, a carboxyl group, an epoxy group, an isocyanate group, or a nitrogen-containing functional group. The adhesive layer according to claim 8, wherein the block copolymer (B) does not contain a crosslinkable functional group in the first block. The adhesive layer of claim 4, wherein the block copolymer (A) comprises 5 to 50 parts by weight of the first block and 50 to 95 parts by weight of the second block. The adhesive layer according to claim 10, wherein the block copolymer (B) includes 5 to 50 parts by weight of the first block and 50 to 95 parts by weight of the 2B block. The adhesive layer according to claim 11, wherein the block copolymer contains a polymerized unit derived from a (meth)acrylic acid ester. The adhesive layer according to claim 1, further comprising a crosslinking agent within the range of 0.01 to 20 parts by weight based on 100 parts by weight of the total content of the block copolymer. An adhesive article comprising an adhesive layer formed from the adhesive composition of claim 1. Opposing substrates facing each other; A printed circuit board positioned between the opposite substrates and having a step difference; And a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to claim 1 positioned between the opposite substrates and absorbing the step difference. A touch panel comprising the touch sensor according to claim 15. A touch sensor according to claim 15 or a touch panel according to claim 16; And a display panel.

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