TW202344653A - Adhesive composition, adhesive layer, and adhesive sheet - Google Patents

Abstract

Provided is an adhesive composition from which an adhesive layer having a low dielectric constant can be formed. Provided is an adhesive composition which contains a polyester-based resin containing a constituent unit derived from a compound having at least 20 carbon atoms and at least two functional groups capable of forming an ester bond, and which has a dielectric constant at a frequency of 100 kHz of 4.0 or less when the adhesive layer is formed. The adhesive composition preferably has a dielectric loss of 0.0001 to 0.15 at a frequency of 100 kHz when the adhesive layer is formed.

Description

Adhesive composition, adhesive layer, and adhesive sheet

The invention relates to an adhesive composition, an adhesive layer, and an adhesive sheet. More specifically, the present invention relates to an adhesive composition, an adhesive layer, and an adhesive sheet that can be favorably used for optical applications.

Image display devices such as organic EL display devices are used in combination with a touch panel having an electrostatic capacitive touch sensor. As electrostatic capacitive touch sensors become more popular, they are increasingly required to have higher performance. Therefore, high performance is also required for the adhesive layer used in electrostatic capacitive touch sensors.

However, due to the thinning and large-screen modules in the above-mentioned image display devices, and the high-definition optical semiconductor elements, the driving noise during the display driving of the image display device will affect the electrostatic capacitive touch sensing. There is a concern that the sensor of the device may have adverse effects and cause malfunction. If the dielectric constant of the adhesive layer is high, it may cause the above-mentioned malfunction caused by driving noise. Therefore, as an adhesive for forming an adhesive layer with a low dielectric constant, for example, an adhesive using a (meth)acrylic polymer as a base polymer has been proposed. The (meth)acrylic polymer will have a long chain. Alkyl (meth)acrylic acid alkyl ester serves as the main component (for example, Patent Document 1). The low dielectric constant adhesive layer can reduce the impact of driving noise from the organic EL panel on the electrostatic capacitive touch sensor. Prior technical literature patent documents

Patent Document 1: Japanese Patent Application Publication No. 2013-082880

[Problem to be solved by the invention]

In recent years, image display devices have been increasingly required to have larger screens and higher definition. As the screen becomes larger, the driving voltage of the image display device increases, and the noise tends to further increase. In addition, as high-definition becomes higher, the number of semiconductor components used increases, so there is a tendency for noise to further increase due to the generation of higher voltages.

In addition, in recent years, there has been a tendency to install touch sensors that have been conventionally installed in image display devices outside the image display device. When the image display device is required to be lighter and thinner, when the touch sensor is installed outside the image display device, as the members used inside and outside the image display device become thinner, the image display device becomes thinner. The emitted noise is easily transmitted to the touch sensor attached to the image display device through the adhesive layer, and the noise of the touch sensor tends to increase. Therefore, the adhesive layer is further required to have a lower dielectric constant.

The present invention is used to solve the above problems, and its purpose is to provide an adhesive composition capable of forming an adhesive layer with a low dielectric constant. [Technical means to solve problems]

The present invention provides an adhesive composition, which contains a polyester resin containing a structural unit derived from a compound having 20 or more carbon atoms and having two or more functional groups capable of forming an ester bond, and the adhesive composition When the adhesive layer is formed of the adhesive composition, the dielectric constant at a frequency of 100 kHz is 4.0 or less.

The above-mentioned polyester-based resin contains a compound having 20 or more carbon atoms as a structural unit and having two or more functional groups capable of forming an ester bond, which tends to have low polarity due to a large number of carbon atoms. Therefore, the adhesive layer formed from the adhesive composition containing the polyester resin tends to have a lower dielectric constant. Moreover, the dielectric constant of the adhesive layer formed using the above-mentioned adhesive composition is 4.0 or less at a frequency of 100 kHz. Thereby, the dielectric constant of the adhesive layer formed from the above-mentioned adhesive composition is low, which is less likely to cause amplification of noise, for example, and can suppress the radiation loss of millimeter waves.

The above adhesive composition preferably has a dielectric loss of 0.0001 to 0.15 at a frequency of 100 kHz when the adhesive layer is formed. If the above-mentioned dielectric loss is within the above-mentioned range, the energy loss caused by heat in the adhesive layer formed by the above-mentioned adhesive composition is smaller, and it is less likely to cause the amplification of noise, and it can suppress millimeter waves. Radiation loss.

The glass transition temperature of the polyester resin is preferably 0°C or lower. By using a polyester resin with a lower glass transition temperature, the adhesive layer formed has better adhesion.

Furthermore, the present invention provides an adhesive layer formed from the above-mentioned adhesive composition.

Furthermore, the present invention provides an adhesive sheet provided with the above-mentioned adhesive layer. [Effects of the invention]

According to the adhesive composition of the present invention, an adhesive layer with a lower dielectric constant can be formed. Therefore, for example, by using the above-mentioned adhesive layer for bonding the touch sensor and the image display device, the noise emitted by the image display device can be prevented from being easily transmitted to the touch sensor. Furthermore, for example, by using the above adhesive layer as an adhesive layer bonded to a millimeter wave antenna substrate used in a millimeter wave antenna, radiation loss of millimeter waves can be suppressed.

[Adhesive composition] The adhesive composition of the present invention contains at least polyester resin. The polyester resin contains at least a structural unit derived from a compound having 20 or more carbon atoms and two or more functional groups capable of forming an ester bond. In addition, in this specification, the said compound may be called "compound (A)". That is, the above-mentioned polyester-based resin is a resin obtained by polymerizing a monomer composition containing the compound (A). The polyester-based resin may contain only one structural unit derived from compound (A), or may contain two or more types.

The dielectric constant of the adhesive layer formed using the above adhesive composition at a frequency of 100 kHz is 4.0 or less, preferably 3.6 or less, more preferably 3.5 or less, further preferably 3.4 or less, further preferably 3.3 or less. , especially preferably below 3.2. By having the dielectric constant below 4.0, the adhesive layer formed from the adhesive composition has a low dielectric constant and is less likely to cause amplification of noise, for example, and can suppress millimeter wave radiation losses. Furthermore, "specific dielectric constant" is the value obtained by dividing "dielectric constant" by "dielectric constant of vacuum". However, since "dielectric constant of vacuum" is 1, in this specification, "dielectric constant" is referred to as "dielectric constant". "Electrical constant" is considered to have the same meaning as "specific permittivity".

The dielectric loss of the adhesive layer formed using the above adhesive composition at a frequency of 100 kHz is preferably 0.15 or less, more preferably 0.13 or less, further preferably 0.12 or less, still more preferably 0.11 or less, still more preferably It is 0.10 or less, more preferably 0.09 or less, especially 0.08 or less. If the above-mentioned dielectric loss is 0.15 or less, the energy loss caused by heat in the adhesive layer formed by the above-mentioned adhesive composition is small, and it is less likely to cause the amplification of noise, and in addition, the radiation loss of millimeter waves can be suppressed. . The dielectric loss is, for example, 0.0001 or more.

In this specification, the dielectric constant and dielectric loss at the frequency of 100 kHz are measured based on JIS K6911, and the dielectric constant and dielectric loss at the frequency of 28 GHz and 60 GHz are measured based on JIS R1660-2. Specifically, The expression is measured by the method described in the examples disclosed below. The dielectric constant and the dielectric loss can be adjusted by adjusting the monomer composition of the polyester resin constituting the adhesive composition, the type or content of additives, and the like.

(polyester resin) The number of carbon atoms in the compound (A) is 20 or more, preferably 24 or more, more preferably 26 or more, further preferably 28 or more, further preferably 30 or more, particularly preferably 32 or more. The compound (A) contained in the polyester resin as a structural unit has a carbon number of 20 or more, and therefore tends to have low polarity. Therefore, the adhesive layer formed of the adhesive composition containing the above-mentioned polyester resin tends to have a low dielectric constant. The carbon number may be, for example, 60 or less, 58 or less, or 56 or less.

The compound (A) is preferably the polyol and/or polycarboxylic acid constituting the above-mentioned polyester resin. That is, compound (A) preferably has two or more hydroxyl groups or carboxyl groups as functional groups capable of forming an ester bond, more preferably 2 to 4, still more preferably 2 to 3, and particularly preferably Has 2.

In addition to the functional group capable of forming an ester bond, compound (A) may or may not have heteroatoms such as oxygen atoms, nitrogen atoms, and sulfur atoms. In the case where the above-mentioned heteroatoms are present, the ratio of the number of carbon atoms in compound (A) to the number of heteroatoms other than the functional group capable of forming an ester bond [number of carbon atoms/number of heteroatoms] is preferably 10 or more, more preferably 15 or above, more preferably 20 or more, still more preferably 25 or more, particularly preferably 30 or more. If the above-mentioned heteroatom is not present or the above-mentioned ratio is 10 or more, the polarity of the polyester-based resin becomes low, and the dielectric constant of the adhesive layer formed from the adhesive composition containing the polyester-based resin becomes low.

Examples of the polycarboxylic acid compound (A) include dimer acids of unsaturated fatty acids. The carbon number of the unsaturated fatty acid is preferably 10 or more, more preferably 16 or more. Examples of the dimer acid of the unsaturated fatty acid include dimer acid of oleic acid, dimer acid of linoleic acid, dimer acid of erucic acid, or dimer acid obtained by combining two of these unsaturated fatty acids. .

Examples of the polyol compound (A) include dimer alcohol. Examples of dimer alcohol include reduced products of dimer acid of unsaturated fatty acids. The carbon number of the unsaturated fatty acid is preferably 10 or more, more preferably 12 or more, further preferably 14 or more, particularly preferably 16 or more. Examples of the above-mentioned dimer alcohol include the reduced product of dimer acid of oleic acid, the reduced product of dimer acid of linoleic acid, the reduced product of dimer acid of erucic acid, and a combination of two of these unsaturated fatty acids. Reduced products of dimer acid, etc.

The polyester-based resin contains at least a structural unit derived from compound (A). The polyester resin may contain structural units derived from polycarboxylic acids other than compound (A) (other polycarboxylic acids), structural units derived from polyols (other polyols) other than compound (A), or other elements thereof. other structural units.

In the above-mentioned polyester-based resin, the content rate of the structural unit derived from the compound (A) is preferably 30 mass % or more with respect to 100 mass % of the total amount of structural units derived from the monomers constituting the above-mentioned polyester-based resin, and more preferably 35 mass % or more, more preferably 40 mass % or more, still more preferably 45 mass % or more, particularly preferably 50 mass % or more. If the content rate is 30% by mass or more, the polarity of the polyester resin becomes low, and the dielectric constant of the adhesive layer formed of the adhesive composition containing the polyester resin becomes low.

Specific examples of the polyester-based resin include: (i) those containing structural units derived from compound (A) as a polyol, structural units derived from other polycarboxylic acids, and, if necessary, structural units derived from other polyols. Polyester resin; (ii) A polyester resin containing structural units derived from compound (A) as a polycarboxylic acid, structural units derived from other polyols, and optionally structural units derived from other polycarboxylic acids; (ii) iii) Contains structural units derived from compound (A) as a polyol, structural units derived from compound (A) as a polycarboxylic acid, and optionally structural units derived from other polycarboxylic acids and/or from other polyols. Structural unit of polyester resin.

Examples of the other polyvalent carboxylic acids include dicarboxylic acids, trivalent or higher carboxylic acids, and the like. Examples of dicarboxylic acids include: malonic acid, succinic acid, glutaric acid, dimethylglutaric acid, adipic acid, trimethyladipic acid, pimelic acid, suberic acid, azelaic acid, decacarboxylic acid, Aliphatic dicarboxylic acids such as dialkanedioic acid, sebacic acid, thiodipropionic acid, and diglycolic acid; dimer acids with less than 19 carbon atoms; 1,2-cyclopentanedicarboxylic acid, 1,2- Cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, norbicarboxylic acid Alicyclic dicarboxylic acids such as acid and adamantane dicarboxylic acid; unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, dodecenyl succinic anhydride and other unsaturated dicarboxylic acids; isophthalic acid Dicarboxylic acid, terephthalic acid, phthalic acid, benzylmalonic acid, 2,2'-biphenyldicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-dicarboxyldiphenyl Ether, naphthalene dicarboxylic acid and other aromatic dicarboxylic acids; their derivatives, etc. Examples of the above-mentioned derivatives include carboxylic acid salts, carboxylic acid anhydrides, carboxylic acid halide compounds, and carboxylic acid esters. Examples of carboxylic acids having a trivalent or higher value include trimellitic acid, pyromellitic acid, adamantanetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, and trimeric acid. Only one type of the above-mentioned other polyvalent carboxylic acids may be used, or two or more types of them may be used.

As the polycarboxylic acid (compound (A) as the polycarboxylic acid and the other polycarboxylic acid described above), a plant-derived polycarboxylic acid may be used. Examples of the above-mentioned plant-derived polycarboxylic acids include polycarboxylic acids generated using glucose (such as succinic acid, adipic acid, itaconic acid, etc.), and those derived from vegetable oils (such as palm oil, coconut oil, rapeseed oil, etc.) Dimer acid of unsaturated fatty acids (such as oleic acid, linoleic acid, erucic acid, etc.), sebacic acid from castor oil, etc.

Examples of the above-mentioned other polyhydric alcohols include diols, trihydric or higher polyhydric alcohols, and the like. Examples of glycols include (poly)alkylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, and polytetramethylene glycol. Class; 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-ethyl-2-butyl-1 ,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5- Pentylene glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-hexanediol, 2,2,4-trimethyl-1, Aliphatic diols such as 6-hexanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol; dimer alcohols with less than 19 carbon atoms; 1,2-cyclohexane Alkanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, spirodiol, tricyclodecanedimethanol, adamantanediol, 2,2,4,4-tetramethyl Alicyclic diols such as 1,3-cyclobutanediol; 4,4'-thiodiphenol, 4,4'-methylenediol, 4,4'-dihydroxybiphenyl, o-, m- And aromatic diols such as p-dihydroxybenzene, 2,5-naphthalenediol, p-xylene glycol, and their ethylene oxide, propylene oxide adducts, etc. Examples of polyhydric alcohols having a trivalent or higher value include pentaerythritol, dipentaerythritol, pentaerythritol, glycerin, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, adamantanetriol, etc. Only one type of the above-mentioned other polyols may be used, or two or more types may be used.

As the above-mentioned polyol (compound (A) as the polyol and the above-mentioned other polyols), plant-derived polyols can also be used. Examples of the above-mentioned plant-derived polyols include polyols produced using glucose (such as ethylene glycol, propylene glycol, butylene glycol, isosorbide, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. ), dimer alcohol as the reducing product of dimer acid of unsaturated fatty acids (such as oleic acid, linoleic acid, erucic acid, etc.) derived from vegetable oils (such as palm oil, coconut oil, rapeseed oil, etc.), as dimer alcohol derived from castor oil 1,10-decanediol, the reduced product of sebacic acid in sesame oil, etc.

In the polyester resin, the total content of structural units derived from dicarboxylic acid and structural units derived from diol is preferably 90% by mass relative to 100% by mass of the total structural units derived from monomers constituting the polyester resin. It is more than 95 mass %, more preferably 95 mass % or more, still more preferably 98 mass % or more, especially 99 mass % or more (for example, 99-100 mass %).

When the compound (A) is a polycarboxylic acid, the content rate of the structural units derived from the compound (A) in the polyester resin is relative to the total amount of structural units derived from the polycarboxylic acid constituting the polyester resin. 100 mass % is, for example, 30 mass % or more, 40 mass % or more, 50 mass % or more, preferably 60 mass % or more, more preferably 70 mass % or more, still more preferably 80 mass % or more, still more preferably Preferably it is 85% by mass or more, more preferably 90% by mass or more, and it may be 95% by mass or more.

When the compound (A) is a polyol, the content rate of the structural unit derived from the compound (A) in the polyester resin is based on 100 mass of the total amount of structural units derived from the polyol constituting the polyester resin. % is, for example, 30 mass% or more, 40 mass% or more, or 50 mass% or more, preferably 60 mass% or more, more preferably 70 mass% or more, still more preferably 80 mass% or more, still more preferably 85 mass % or more, preferably 90 mass % or more, and 95 mass % or more is also acceptable.

The content of the structural unit derived from the polycarboxylic acid in the polyester resin is, for example, 0.5 equivalent or more, preferably 0.58 equivalent or more, more preferably 0.66 equivalent or more, further preferably 0.83 equivalent or more, based on 1 equivalent of the polyol. , more preferably 0.88 equivalent or more, particularly preferably 0.95 equivalent or more. Moreover, the above-mentioned content is, for example, 2.0 equivalents or less, preferably 1.7 equivalents or less, more preferably 1.5 equivalents or less, further preferably 1.2 equivalents or less, still more preferably 1.1 equivalents or less, based on 1 equivalent of polyol. 1.05 equivalent or less.

In the above-mentioned polyester-based resin, the equivalent ratio of the structural unit derived from the polycarboxylic acid and the structural unit derived from the polyol is not particularly limited, and an appropriate equivalent ratio can be set taking into consideration the target polymer physical properties, polymerizability, etc. If the equivalent ratio of the polycarboxylic acid is high, the characteristics based on the polycarboxylic acid can be easily expressed. In addition, if the equivalent ratio of the polyol is high, the characteristics based on the polyol can be easily expressed.

The weight average molecular weight (Mw) of the polyester resin is preferably 3,000 or more, more preferably 5,000 or more, further preferably 10,000 or more, further preferably 15,000 or more, and particularly preferably 20,000 or more. If the weight average molecular weight is 3,000 or more, the cohesive force of the adhesive layer becomes high, and the holding power and high temperature holding power are improved. The weight average molecular weight is, for example, 300,000 or less, preferably 250,000 or less, more preferably 200,000 or less, further preferably 150,000 or less.

The glass transition temperature (Tg) of the above-mentioned polyester-based resin is preferably 10°C or lower, more preferably 5°C or lower, further preferably 0°C or lower, further preferably less than -5°C, and particularly preferably -10°C. the following. By using a polyester resin with a low Tg, the adhesive layer formed has excellent adhesion. Moreover, from the viewpoint of the cohesion of the adhesive layer, the Tg of the polyester resin is preferably -60°C or higher, more preferably -55°C or higher, further preferably -50°C or higher, and particularly preferably -45 ℃ or above. The Tg of the polyester resin can be adjusted by appropriately changing the monomer composition (ie, the type or usage ratio of the monomers used in the synthesis of the polyester resin). In addition, the Tg of the said polyester-type resin is measured as the Tg of an adhesive layer, specifically, for example, it is measured by the method described in an Example.

The adhesive composition preferably contains the polyester resin as a base polymer. The content rate of the polyester resin based on 100 mass% of the total amount of all resins contained in the adhesive composition is preferably more than 50 mass%, more preferably 60 mass% or more, and still more preferably 70 mass% or more. , it can also be 80 mass% or more.

The method for obtaining the above-mentioned polyester resin is not particularly limited, and a known or commonly used polyester resin polymerization method can be appropriately used. Specifically, the above-mentioned polyester-based resin can be obtained by polycondensation of a polycarboxylic acid and a polyhydric alcohol in the same manner as a normal polyester. More specifically, the reaction between the carboxyl group of the polycarboxylic acid and the hydroxyl group of the polyhydric alcohol can be carried out while removing the water (generated water) etc. generated by the above reaction to the outside of the reaction system. This synthetic polyester resin. Examples of methods for removing the above-mentioned generated water out of the reaction system include blowing an inert gas into the reaction system and taking out the generated water and the inert gas out of the reaction system, or using reaction water such as toluene or xylene to discharge the solvent. The method of azeotropic dehydration, the method of distilling and removing the generated water from the reaction system under reduced pressure (reduced pressure method), etc. In addition, the above-mentioned polyester-based resin may also adopt a transesterification reaction using a polyester and a polyol.

Examples of the polyvalent ester include esters of the above-mentioned polycarboxylic acids. Examples of the ester include alkyl esters such as methyl ester and ethyl ester; hydroxyalkyl esters such as 2-hydroxyethyl ester; and the like. Among them, hydroxyalkyl ester is preferred, and 2-hydroxyethyl ester is more preferred. In this case, there are the following advantages: The melting point tends to be lower than that of polycarboxylic acids or alkyl esters thereof, and the workability is excellent. The polyester resin obtained has a hydroxyl group at the terminal end, and is compatible with the following hardeners such as isocyanate hardeners. It has excellent reactivity and the polyester resin has excellent hydrolysis resistance. In addition, bis(2-hydroxyethyl) terephthalate can be synthesized by chemical recycling of PET, so it has excellent environmental adaptability.

The reaction temperature or reaction time when performing various reactions such as the above-mentioned polycondensation, and the degree of pressure reduction (pressure in the reaction system) when using the pressure reduction method can efficiently obtain a polyester-based resin with target characteristics (such as molecular weight) Set appropriately. Generally, it is appropriate to set the reaction temperature to 150°C or higher (for example, 180°C to 260°C), but it is not particularly limited. By setting the reaction temperature within the above range, a good reaction rate can be obtained, productivity can be improved, and deterioration of the produced polyester-based resin can be easily prevented or suppressed. The reaction time is not particularly limited, but is approximately 3 to 48 hours. When the pressure reduction method is used, the degree of pressure reduction may be, for example, 4 kPa to 0.1 kPa, but is not particularly limited. By setting the pressure in the reaction system within the above range, the water generated by the reaction can be efficiently distilled out of the reaction system, making it easy to maintain a good reaction rate. In addition, when the reaction temperature is relatively high, by setting the pressure in the reaction system to be equal to or higher than the above-mentioned lower limit, it is easy to prevent the polycarboxylic acid or polyhydric alcohol as the raw material from being distilled out of the reaction system. From the viewpoint of maintaining stable pressure within the reaction system, it is usually appropriate to set the pressure within the reaction system to 0.1 kPa or more.

In the above reaction, an appropriate amount of a known or commonly used catalyst can be used to perform esterification and condensation in the same manner as in ordinary polyester synthesis. Examples of the catalyst include titanium-based, germanium-based, antimony-based, tin-based, zinc-based metal compounds; strong acids such as p-toluenesulfonic acid or sulfuric acid; and the like. The amount of catalyst used can be appropriately set according to the reaction speed, etc.

In the above-mentioned process of synthesizing polyester resin through the reaction of polyhydric alcohol and polycarboxylic acid or polyester, a solvent may or may not be used. The above synthesis can be carried out substantially without the use of organic solvents, that is, intentionally without the use of organic solvents.

(cross-linking agent) The above-mentioned adhesive composition may also contain a cross-linking agent. The above-mentioned cross-linking agent has the function of cross-linking the above-mentioned polyester-based resins with each other, and can also function as a chain-branching agent for the polyester-based resin. If the above-mentioned cross-linking agent is included, a cross-linked structure of the polyester-based resin will be formed in the formed adhesive layer, and the cohesive force will be improved. Only one type of cross-linking agent may be used, or two or more types of cross-linking agents may be used.

Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, melamine-based cross-linking agents, peroxide-based cross-linking agents, urea-based cross-linking agents, and metal alkoxide-based cross-linking agents. , Metal chelate cross-linking agent, metal salt cross-linking agent, carbodiimide cross-linking agent, oxazoline cross-linking agent, aziridine cross-linking agent, amine cross-linking agent, silicone Cross-linking agent, silane cross-linking agent, etc. Among the above-mentioned cross-linking agents, from the viewpoint of excellent impact resistance of the formed adhesive layer, an isocyanate-based cross-linking agent is preferred.

The number of functional groups in the above-mentioned cross-linking agent is 2 or more, preferably 2-4, more preferably 2-3. In particular, from the viewpoint of particularly excellent impact resistance of the adhesive layer formed, an isocyanate-based crosslinking agent having a functional group number within the above range is preferred.

Examples of the isocyanate cross-linking agent (polyfunctional isocyanate compound) include: 1,2-ethylidene diisocyanate, 1,4-butylene diisocyanate, 1,5-pentamethylene diisocyanate, 1, 6-Hexamethylene diisocyanate and other low-grade aliphatic polyisocyanates; cyclopentyl diisocyanate, cyclohexyl diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate and other alicyclic Polyisocyanates; aromatic polyisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, etc. Examples of the isocyanate cross-linking agent include lower fats such as 1,5-pentamethylene diisocyanate-modified isocyanurate and 1,6-hexamethylene diisocyanate-modified isocyanurate. Family polyisocyanate modified isocyanurate. Furthermore, examples may include: ethylene glycol/1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, 1,5-pentamethylene diisocyanate, and 1,6-hexamethylene Lower aliphatic polyisocyanate adducts such as diisocyanate; 1,4-butanediol/1,2-ethylidene diisocyanate, 1,4-butylene diisocyanate, 1,5-pentamethylene diisocyanate Isocyanate, 1,6-hexamethylene diisocyanate and other lower aliphatic polyisocyanate adducts; 1,6-hexanediol/1,2-ethylidene diisocyanate, 1,4-butylene diisocyanate , 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate and other lower aliphatic polyisocyanate adducts; trimethylolpropane/toluene diisocyanate adduct, trimethylolpropane Propane/hexamethylene diisocyanate adduct, trimethylolpropane/xylylene diisocyanate adduct, etc.

Examples of the epoxy cross-linking agent (polyfunctional epoxy compound) include: N,N,N',N'-tetraglycidyl metaxylylenediamine, diglycidyl aniline, 1,3-bis (N,N-diglycidylamine methyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether , polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether , trimethylolpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, tris(2-hydroxyethyl)triglycidyl isocyanurate, resorcinol diglycidyl Glyceryl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule, etc.

The content of the cross-linking agent in the adhesive composition is preferably 0.1 parts by mass or more based on 100 parts by mass of the total amount of the polyester resin. Moreover, the above-mentioned content is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, further preferably 20 parts by mass or less, based on 100 parts by mass of the total amount of the polyester-based resin. , more preferably 12 parts by mass or less, particularly preferably 10 parts by mass or less. If the content of the cross-linking agent is 0.1 parts by mass or more, the cohesion of the adhesive layer will be improved. On the other hand, if the content of the cross-linking agent is 30 parts by mass or less, the adhesive layer has moderate flexibility and the adhesive force is easily improved.

(cross-linking catalyst) In order to make the cross-linking reaction proceed more efficiently, the above-mentioned adhesive composition may also contain a cross-linking catalyst in addition to the above-mentioned cross-linking agent. Only one type of the above-mentioned cross-linking catalyst may be used, or two or more types may be used.

Examples of the cross-linking catalyst include zirconium-containing compounds (zirconium-based catalysts) such as zirconium tetraacetyl acetone, zirconium monoacetyl acetonate, zirconium acetate ethyl acetate, and zirconium octoate compounds; dioctyltin dilaurate, Tin (Sn) compounds (tin-based catalysts) such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diethyl acetone, tetra-n-butyltin, trimethyltin hydroxide, butyltin oxide, etc.; second aluminum butoxide , aluminum triacetyl acetonate, aluminum bis acetate ethyl acetate, aluminum triacetyl ethyl acetate and other aluminum-containing compounds (aluminum catalysts); iron acetate acetonate and other iron-containing compounds (iron-based catalysts); titanic acid Tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetraoctyl titanate, titanium acetyl acetonate, titanium tetraacetyl acetonate, titanium acetate ethyl acetate and other titanium-containing compounds (titanium series Catalyst) and other organic metal catalysts.

The content of the cross-linking catalyst in the adhesive composition is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, and still more preferably 0.01 parts by mass relative to 100 parts by mass of the total amount of the polyester resin. above. Furthermore, the content of the cross-linking catalyst is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and still more preferably 1 part by mass or less based on 100 parts by mass of the total amount of the polyester resin.

(Hydrolysis resistant agent) The above-mentioned adhesive composition may also contain a hydrolysis-resistant agent (anti-hydrolysis agent). By adding a hydrolysis-resistant agent, the hydrolysis reaction in the adhesive composition or adhesive layer is suppressed, making it easier to obtain good durability. Only one type of the above-mentioned hydrolysis-resistant agent may be used, or two or more types may be used.

The above-mentioned hydrolysis-resistant agent is not particularly limited, and known or commonly used hydrolysis-resistant agents can be used. Examples of the hydrolysis-resistant agent include oxazoline group-containing compounds, epoxy group-containing compounds, carbodiimide group-containing compounds, and the like. Among them, compounds containing carbodiimide groups are preferred.

Examples of the above carbodiimide group-containing compounds include: dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, and dioctyl Carbodiimide, tert-butylisopropylcarbodiimide, diphenylcarbodiimide, di-tert-butylcarbodiimide, di-β-naphthylcarbodiimide, polycarbodiimide Amine, cyclic structure carbodiimide, etc. The above-mentioned polycarbodiimide is a compound in which two or more carbodiimide groups are bonded through a bonding group composed of an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof. Moreover, the above-mentioned cyclic structural carbodiimide is a compound having one or more carbodiimide groups in the molecular structure, and is formed by an aliphatic group, an alicyclic group, an aromatic group, or the like. The bonding group formed by the combination bonds the first nitrogen atom and the second nitrogen atom of the carbodiimide group to form a ring structure. The above-mentioned bonding group may have a heteroatom or a substituent.

The content of the hydrolysis-resistant agent in the adhesive composition is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and further preferably 0.3 parts by mass or more relative to 100 parts by mass of the total amount of the polyester resin. . The content of the hydrolysis-resistant agent is, for example, 5 parts by mass or less, preferably 3 parts by mass or less, and more preferably 1 part by mass or less.

(Tackiness imparting resin) The above-mentioned adhesive composition may also contain an adhesive imparting resin. By adding adhesion-imparting resin, the adhesion to the adherend is improved. Only one type of the above-mentioned tackifying resin may be used, or two or more types may be used.

The above-mentioned tackifying resin is not particularly limited, and any known or commonly used tackifying resin can be used. Examples of the above-mentioned tackifier-imparting resin include: phenol-based tackifier-imparting resin, terpene-based tackifier-imparting resin, rosin-based tackifier-imparting resin, hydrocarbon-based tackifier-imparting resin, epoxy-based tackifier-imparting resin, polyamide-based tackifier-imparting resin, and elastic system Adhesion-imparting resin, ketone-based adhesion-imparting resin, etc.

Examples of the phenolic tackifier-imparting resin include terpene phenol resin, hydrogenated terpene phenol resin, alkyl phenol resin, and rosin phenolic resin. The above-mentioned terpene phenol resin is a polymer containing a terpene residue and a phenol residue. Examples thereof include copolymers of terpenes and phenol compounds (terpene-phenol copolymer resins), homopolymers or copolymers of para-terpenes. The material is phenol-modified (phenol-modified terpene resin). Examples of the terpenes constituting the terpene phenol resin include monoterpenes such as α-pinene, β-pinene, and limonene (d isomer, l isomer, d/l isomer (dipentene), etc.) alkenes. The hydrogenated terpene phenol resin is a resin having a structure obtained by hydrogenating the above terpene phenol resin. The above-mentioned alkylphenol resin is a resin obtained from alkylphenol and formaldehyde (oil-based phenol resin). Examples of the alkylphenol resin include novolac-type alkylphenol resin and novolac-type alkylphenol resin. The above-mentioned rosin phenolic resin is a phenol-modified product of rosin or various rosin derivatives described below. The above-mentioned rosin phenolic resin can be obtained, for example, by a method in which phenol is added to rosins or various rosin derivatives described below in the presence of an acid catalyst and thermally polymerized.

Examples of the terpene-based adhesive-imparting resin include polymers of terpenes (typically monoterpenes) such as α-pinene, β-pinene, d-limonene, l-limonene, and dipentene. The above-mentioned terpene polymer may be a homopolymer of one terpene, or a copolymer of two or more terpenes. Examples of terpene homopolymers include α-pinene polymer, β-pinene polymer, and dipentene polymer. The above-mentioned modified terpene-based adhesion-imparting resin is obtained by modifying the above-mentioned terpene resin (modified terpene resin). Examples of the modified terpene resin include styrene-modified terpene resin, hydrogenated terpene resin, and the like.

Examples of the rosin-based adhesion-imparting resin include rosin-based and rosin derivative resins. Examples of the above-mentioned rosins include: unmodified rosin (raw rosin) such as rosin gum, wood rosin, and tall oil rosin; modified rosins obtained by modifying these unmodified rosins by hydrogenation, disproportionation, polymerization, etc. Sexual rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, other chemically modified rosin, etc.). Examples of the rosin derivative resin include the above-mentioned rosin derivatives. Examples of the rosin derivative resin include: rosin esters such as unmodified rosin esters which are esters of unmodified rosin and alcohols, and modified rosin esters which are esters of modified rosin and alcohols; Unsaturated fatty acid-modified rosins obtained by modifying unsaturated fatty acids; unsaturated fatty acid-modified rosin esters obtained by modifying rosin esters with unsaturated fatty acids; rosins or various rosin derivatives mentioned above Rosin alcohols obtained by reduction treatment of carboxyl groups; rosins or metal salts of various rosin derivatives mentioned above, etc. Specific examples of the above-mentioned rosin esters include methyl ester, triethylene glycol ester, glycerol ester, pentaerythritol ester of unmodified rosin or modified rosin.

Examples of the hydrocarbon-based tackifying resin include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic-aromatic petroleum resins (styrene-olefin copolymers, etc.), aliphatic hydrocarbon resins, etc. Alicyclic petroleum resins, hydrogenated hydrocarbon resins, benzofuran resins, benzofuran-indene resins, etc.

The content of the tackifying resin in the adhesive composition is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 15 parts by mass or more based on 100 parts by mass of the total amount of the polyester resin. . The content of the above-mentioned tackifying resin is, for example, 70 parts by mass or less, preferably 60 parts by mass or less, and more preferably 50 parts by mass or less.

The above-mentioned adhesive composition may also contain other components than the above-mentioned components as necessary within the range that does not impair the effects of the present invention. Examples of the above-mentioned other components include resins other than the above-mentioned polyester-based resins, curing catalysts, cross-linking accelerators, polymerization initiators, oligomers, anti-aging agents, fillers (metal powder, organic fillers, inorganic fillers). Fillers, etc.), colorants (pigments or dyes, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, UV absorbers, polymerization inhibitors Agents, rust inhibitors, granules, foils, flame retardants, silane coupling agents, ion capture agents, etc. Only one type of the above-mentioned other components may be used, or two or more types may be used.

The adhesive composition may have any form, and examples thereof include solvent type, emulsion type, hot-melt type, and solvent-free type.

As mentioned above, the adhesive composition of the present invention can be solvent-based, that is, it can contain an organic solvent. The above-mentioned organic solvent is not particularly limited as long as it is an organic compound used as a solvent. Examples thereof include hydrocarbon solvents such as cyclohexane, hexane, heptane, and methylcyclohexane; and aromatic solvents such as toluene and xylene. ; Ester-based solvents such as butyl acetate, ethyl acetate, methyl acetate, etc.; Ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.; Methanol, ethanol, propanol, butanol, isopropyl alcohol, etc. Alcohol-based solvents; carbonate-based solvents such as dimethyl carbonate and diethyl carbonate, etc. Only one type of the above-mentioned organic solvent may be used, or two or more types may be used.

[Adhesive layer] The above adhesive composition can be used to form an adhesive layer. The adhesive layer formed using the adhesive composition of the present invention is sometimes referred to as the "adhesive layer of the present invention". The above-mentioned adhesive layer can be produced, for example, by applying the above-mentioned adhesive composition to the release treatment surface of the release liner or the base material to form an adhesive composition layer, and then desolvating the above-mentioned adhesive composition by heating. The adhesive composition layer is cured.

The adhesive layer preferably contains the polyester resin (especially the polyester resin as a base polymer). The content rate of the polyester resin based on 100 mass% of the total amount of all resins included in the adhesive layer is preferably more than 50 mass%, more preferably 60 mass% or more, and still more preferably 70 mass% or more. It may be 80 mass% or more, 90 mass% or more, or 95 mass% or more.

The content rate of the polyester resin in the adhesive layer is preferably more than 50 mass%, more preferably 60 mass% or more, and further preferably 70 mass% or more relative to 100 mass% of the total amount of the adhesive layer. , it can also be 80 mass% or more.

The above-mentioned adhesive layer may also contain other components other than the above-mentioned polyester resin within the range that does not impair the effects of the present invention. Examples of the above-mentioned other components include those illustrated and described as components that can be included in the above-mentioned adhesive composition. Only one type of the above-mentioned other components may be used, or two or more types may be used.

The total light transmittance (based on JIS K7361-1) of the above-mentioned adhesive layer is not particularly limited, but is preferably 88% or more, more preferably 89% or more, and further preferably 90% or more. If the total light transmittance is 88% or more, excellent transparency or excellent appearance can be obtained, and it can be used well for optical purposes.

Furthermore, by using a laminate in which an adhesive layer and an optical film are laminated, the total light transmittance is evaluated using the same method as above, and the total light transmittance of the adhesive layer can be set as a standard. Specifically, for example, when the total light transmittance of the optical film is close to 100%, it can be judged that the total light transmittance of the laminated body and the total light transmittance of the adhesive layer are approximately the same.

The haze (based on JIS K7136) of the above-mentioned adhesive layer is not particularly limited, but is preferably 1.5% or less, more preferably 1.4% or less, still more preferably 1.3% or less, still more preferably 1.2% or less, still more preferably It is 1.0% or less, more preferably 0.9% or less, still more preferably 0.8% or less, still more preferably 0.7% or less, particularly preferably 0.6% or less. If the haze is 1.5% or less, excellent transparency or excellent appearance can be obtained, and it can be used favorably for optical purposes.

Furthermore, by using a laminate in which an adhesive layer and an optical film are laminated, the haze is evaluated using the same method as above, and the haze value of the adhesive layer can be used as a standard. Specifically, for example, when the haze value of the optical film is close to 0%, it can be determined that the haze value of the laminate is the same as the haze value of the adhesive layer.

Regarding the hue of the adhesive layer, b ^* represented by the L ^* a ^* b ^* color expression system is preferably in the range of 0.0 to 2.0, more preferably 0.0 to 1.5, further preferably 0.0 to 1.2, and further 0.0 to 1.0 is preferred, 0.0 to 0.8 is more preferred, and 0.0 to 0.5 is particularly preferred. b ^* represents the yellow-blue axis, in the range of 0.0 to 2.0. The smaller the value, the weaker the yellow tone. Excellent transparency or excellent appearance can be obtained, and it can be used well for optical purposes. In this specification, the b ^* represented by the above-mentioned L ^* a ^* b ^* color system of the adhesive layer is a value calculated based on the linear transmittance of the adhesive layer.

Furthermore, by using a laminate in which an adhesive layer and an optical film are laminated, the hue (b ^* ) can be evaluated using the same method as above, and the hue (b ^* ) of the adhesive layer can be set as a standard. Specifically, for example, when the hue of the optical film is close to 0, it can be determined that the hue (b ^* ) of the laminated body is substantially the same as the hue (b ^* ) of the adhesive layer.

The total light transmittance, haze, and b ^* of the above-mentioned adhesive layer can be adjusted by adjusting the monomer composition of the polyester resin constituting the adhesive composition used to form the adhesive layer, the type or content of the additives, etc. adjust.

The 180° peeling adhesion force of the above-mentioned adhesive layer relative to the glass plate when the stretching speed is 300 mm/min is not particularly limited, but is preferably 1 N/20 mm or more, more preferably 2 N/20 mm or more, and further Preferably it is 3 N/20 mm or more. If the above-mentioned 180° peeling adhesion force is more than a fixed value, the adhesion to glass and the ability to suppress bulges in steps will be even better. The above-mentioned 180° peeling adhesive force is not particularly limited, but is preferably 20 N/20 mm or less, more preferably 18 N/20 mm or less, and further preferably 16 N/20 mm or less.

Furthermore, by using a laminated body in which an adhesive layer and an optical film are laminated, and evaluating the 180° peel adhesion using the same method as above, it can be set as the standard for the 180° peel adhesion of the adhesive layer.

The above-mentioned glass plate is not particularly limited, and for example, the product name is "Soda Lime Glass #0050" (manufactured by Matsunami Glass Industry Co., Ltd.). Moreover, alkali-free glass, chemically strengthened glass, etc. can also be mentioned.

The above-mentioned 180° peel adhesion can be determined by the monomer composition of the polyester resin constituting the adhesive composition used to form the adhesive layer, the weight average molecular weight, the usage amount (added amount) of the cross-linking agent, and the types of other additives. or content, etc. to be controlled.

The storage elastic modulus of the above-mentioned adhesive layer at 23°C is not particularly limited, but is preferably 5.0×10 ⁴ Pa or above, more preferably 7.5×10 ⁴ Pa or above, and further preferably 1.0×10 ⁵ Pa or above. If the storage elastic modulus is 5.0×10 ⁴ Pa or more, it is less likely to cause dents during operation and it is easier to obtain good bonding reliability, so it is preferable. In addition, from the viewpoint of step followability and foreign matter absorbability, the storage elastic modulus of the above-mentioned adhesive layer at 25°C is preferably 2.0×10 ⁶ Pa or less, more preferably 1.5×10 ⁶ Pa or less, and further preferably Preferably, it is 1.0×10 ⁶ Pa or less. The storage elastic modulus of the adhesive layer is measured when performing dynamic viscoelasticity at a frequency of 1 Hz. The above-mentioned storage elastic modulus is the real part of the shear modulus expressed as a complex number, and can be converted with the tensile elastic modulus, etc. by taking the Poisson's ratio of the sample into consideration.

The storage elastic modulus of the above-mentioned adhesive layer can be determined by the monomer composition of the polyester resin constituting the adhesive composition used to form the adhesive layer, the weight average molecular weight, the usage amount (added amount) of the cross-linking agent, and others. Control the type or content of additives.

The gel fraction (ratio of insoluble components) of the adhesive layer is not particularly limited, but is preferably 3% or more, more preferably 5% or more, further preferably 10% or more, particularly preferably 15% or more. The gel fraction (ratio of insoluble components) of the adhesive layer is not particularly limited, but is preferably 95% or less, more preferably 90% or less, and still more preferably 85% or less. If the gel fraction is more than 3%, the cohesion of the adhesive layer will be improved, making it less likely to cause dents during operation. If the gel fraction is 95% or less, moderate softness can be obtained, adhesion and step following properties are further improved, and it is less likely to absorb foreign matter.

The gel fraction can be determined, for example, by the monomer composition of the polyester resin constituting the adhesive composition used to form the adhesive layer, the weight average molecular weight, the usage amount (added amount) of the cross-linking agent, the type of other additives, or Content, etc. are controlled.

The thickness of the above-mentioned adhesive layer is not particularly limited, but is preferably 10 to 250 μm, more preferably 10 to 200 μm, further preferably 10 to 175 μm, further preferably 10 to 150 μm, further preferably 10 ~125 μm, preferably 10~100 μm. If the thickness is more than a fixed value, it is preferable because the step followability or the bonding reliability are improved. If the thickness is less than a fixed value, it is less likely to absorb foreign matter during handling, and the handleability and manufacturability are excellent, so it is preferable. In addition, the above-mentioned adhesive layer can suppress the amplification of noise even when the thickness is relatively thin.

The manufacturing method of the above-mentioned adhesive layer is not particularly limited. For example, it can be manufactured by coating (coating) the above-mentioned adhesive composition on the base material or the release-treated surface of the release liner that has been subjected to release treatment. A coating layer is formed, and then, if necessary, desolvation or thermal hardening by heating is performed to solidify the coating layer.

[Adhesive sheet] An adhesive sheet can be obtained using the adhesive layer of the present invention. The adhesive sheet provided with the adhesive layer of the present invention is sometimes referred to as the "adhesive sheet of the present invention." The above-mentioned adhesive sheet may be a double-sided adhesive sheet in which both sides become the surface of the adhesive layer, or may be a single-sided adhesive sheet in which only one side becomes the surface of the adhesive layer. Among them, from the viewpoint of bonding two members to each other, a double-sided adhesive sheet is preferred. In addition, in this specification, what is called "adhesive sheet" also includes those in the form of a strip, that is, "tape" is also included. In addition, in this specification, the surface of the adhesive layer may be called "adhesive surface".

The above-mentioned adhesive sheet may be a so-called "base material-less type" adhesive sheet that does not have a base material (base material layer) (hereinafter, sometimes referred to as a "base material-less adhesive sheet"), or may have a base material. Type of adhesive sheet (hereinafter sometimes referred to as "adhesive sheet with base material"). The above-mentioned base-less adhesive sheet can be, for example, a double-sided adhesive sheet containing only the adhesive layer of the present invention, or an adhesive layer including the adhesive layer of the present invention and an adhesive layer other than the adhesive layer of the present invention (sometimes Double-sided adhesive sheets (called "other adhesive layers"), etc. On the other hand, examples of the adhesive sheet with a base material include an adhesive sheet having the adhesive layer of the present invention on at least one side of the base material. Among them, a substrate-free adhesive sheet (substrate-free double-sided adhesive sheet) is preferred, and a substrate-free double-sided adhesive sheet including only the adhesive layer of the present invention is more preferred. In addition, an adhesive sheet having an adhesive layer on both sides of the base material (a double-sided adhesive sheet with a base material) is also preferred. The adhesive layers on both sides of the above-mentioned double-sided adhesive sheet with a substrate can both be the adhesive layer of the present invention, or one can be the adhesive layer of the present invention and the other can be other adhesive layers. In addition, the above-mentioned "base material (base material layer)" does not include a release liner that is peeled off when using (attaching) the adhesive sheet.

When the above-mentioned adhesive sheet is an adhesive sheet with a base material, radiation loss of millimeter waves caused by the base material will occur, so an adhesive sheet without a base material is preferred. However, when the base material is made of a material with low dielectric constant and low dielectric loss, it can also be an adhesive sheet attached to the base material.

The base material is an element that functions as a support for the adhesive layer in the adhesive sheet. Examples of the base material include plastic base materials (especially plastic films). The above-mentioned base material may be a single layer or a laminate of base materials of the same type or different types.

The above-mentioned base material is not particularly limited, and examples thereof include various optical films such as plastic films, anti-reflection (AR) films, anti-glare (AG) films, polarizing plates, and phase difference plates. Examples of materials for the plastic film include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, and triacetyl fiber. TAC, polystyrene, polyarylate, polyimide, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name "ARTON" (cyclic olefin polymer , JSR Co., Ltd.), trade name "ZEONOR" (cyclic olefin polymer, manufactured by Japan Zeon Co., Ltd.) and other plastic materials such as cyclic olefin polymers and fluorine polymers. Furthermore, only one type of plastic material can be used, or two or more types of plastic materials can be used.

In order to improve the adhesion and retention with the adhesive layer, the surface of the above-mentioned base material on the side with the above-mentioned adhesive layer can also be subjected to surface treatment, such as corona discharge treatment, plasma treatment, frosting treatment, ozone exposure Physical treatments such as treatment, flame exposure treatment, high-voltage electric shock exposure treatment, and ionizing radiation treatment; chemical treatments such as chromic acid treatment; easy-adhesion treatment using a coating agent (primer), etc. It is preferable that the entire surface of the adhesive layer side of the base material be subjected to surface treatment for improving adhesion.

The above-mentioned base material may also be a noise reduction film. The noise reduction film is not particularly limited as long as it has the performance of reducing noise. An example of the noise reduction film is one in which a noise reduction layer is formed on at least one side of the film base material. The noise reduction layer may be a single layer or a plurality of layers, and is not particularly limited as long as it has the function of reducing electromagnetic noise. From the perspective of transparency, a transparent conductive layer is preferred. As the transparent conductive layer, a thin film layer formed of conductive organic or inorganic materials, or a conductive layer formed by partial contact of conductive organic or inorganic materials can be used.

The above-mentioned adhesive sheet may also be provided with a release liner on the adhesive surface before use. The release liner protects the connected adhesive surfaces before using the adhesive layer, and peels off when using the adhesive layer. Furthermore, when the above-mentioned adhesive sheet is a double-sided adhesive sheet, each adhesive surface can be protected by two release liners respectively, or the two surfaces can be used as one of the release surfaces and one release liner can be rolled into a roll shape. form to be protected. The release liner is used as a protective material for the adhesive layer and is peeled off when attached to the adherend. In addition, when the above-mentioned adhesive sheet is an adhesive sheet without a base material, the release liner can also be used as a support for the adhesive layer. Furthermore, it is not necessary to provide a release liner.

Examples of the base material of the release liner include: polyethylene film, polypropylene film, polybutylene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene film, etc. Ethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene -(meth)acrylic acid copolymer film, ethylene-(meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Furthermore, cross-linked films thereof may also be exemplified. Furthermore, a laminated film thereof may also be used.

It is preferable that the release surface of the release liner (especially the surface in contact with the adhesive layer) is subjected to a release treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

The thickness of the release liner is not particularly limited, but is, for example, about 20 to 150 μm.

[use] The uses of the adhesive composition of the present invention, the adhesive layer of the present invention, and the adhesive sheet of the present invention are not particularly limited and can be used for any purpose. For example, it can be used for optical applications, that is, for bonding to optical components. By using the adhesive composition of the present invention, the adhesive layer of the present invention, and the adhesive sheet of the present invention for optical purposes, reliability is excellent. For example, it is presumed that the polyester resin, unlike the acrylic resin, does not have a carbon-carbon double bond and therefore is less susceptible to yellowing over time and is particularly suitable for optical applications.

The adhesive composition of the present invention, the adhesive layer of the present invention, and the adhesive sheet of the present invention are used, for example, in mounting (assembly) various components or parts to specific parts (such as casings, front surfaces, etc.) in optical components such as electrical and electronic equipment. Used when using panels, window parts, etc.). Furthermore, "electrical and electronic equipment" means equipment that is at least either an electrical machine or an electronic machine. Examples of the electrical and electronic equipment include image display devices such as liquid crystal displays, organic/inorganic electroluminescent displays, and plasma displays, and portable electronic equipment. Examples of the image display device include the image display device of the portable electronic device, a vehicle-mounted display, a digital signage (electronic signage, electronic bulletin board), and the like. Furthermore, the above-mentioned image display device may be a so-called "rigid type" or a so-called "soft type" (structure), or may be a so-called "foldable type" or "rollable type" that is bendable. Or folded form (structure).

Examples of the above-mentioned portable electronic devices include mobile phones, smart phones, tablet PCs, notebook PCs, and various wearable devices (for example, wristbands worn on the wrist like watches, using clamps or straps, etc. Modular types that are worn on part of the body, eye-wearing types including glasses types (single-eyed or double-eyed types, including head-mounted types), clothing types that are worn in the form of accessories such as sweatshirts, socks, hats, etc. , ear-worn models worn on the ears like headphones, etc.), digital cameras, digital video recorders, audio equipment (Walkmans, IC recorders, etc.), computers (calculators, etc.), portable game consoles, electronics Dictionaries, electronic notebooks, electronic books, vehicle-mounted information equipment, portable radios, portable TVs, portable printers, portable scanners, portable modems, etc. Furthermore, in this specification, "carrying" means not only being portable, but also having portability to the extent that an individual (standard adult) can carry it relatively easily.

As the use of the adhesive layer of the present invention and the adhesive sheet of the present invention, specifically, the use of the touch sensor and the image display device disposed between the touch sensor and the image display device is preferred. Fit for purpose. The adhesive layer of the present invention is preferably directly laminated with the above-mentioned touch sensor. In addition, the adhesive layer of the present invention can be directly laminated on the image display device, or can be laminated via other layers such as polarizing films. The adhesive layer of the present invention is less likely to cause noise amplification, so that the noise emitted from the image display device is less likely to be transmitted to the touch sensor.

Furthermore, the adhesive layer of the present invention and the adhesive sheet of the present invention can be used to bond components constituting an antenna (millimeter wave antenna) used for millimeter wave communications. The adhesive layer of the present invention has the characteristics of low dielectric constant and dielectric loss in high frequency bands such as millimeter waves, so it can suppress the radiation loss of millimeter waves. In this specification, "millimeter wave communication" refers to communication in the frequency band of 20 GHz to 300 GHz.

[Optical laminated body] By arranging the adhesive layer of the present invention or the adhesive sheet of the present invention between the touch sensor and the image display device, a touch sensor, the adhesive layer of the present invention, and an image display device are obtained in sequence. Optical laminated body of image display device (optical laminated body of the present invention). The above-mentioned optical laminate may have a single layer or multiple layers of touch sensors and adhesive layers. When there are multiple touch sensors, each touch sensor is preferably laminated through an adhesive layer. When there are a plurality of adhesive layers, the plurality of adhesive layers may be layers with the same composition or thickness, or may be different layers. When there are multiple adhesive layers, at least one layer is the adhesive layer of the present invention. Preferably, all adhesive layers disposed between the touch sensor and the image display device are adhesive layers of the present invention.

The above image display device can be exemplified by the above image display device. The above-mentioned touch sensor is an electrostatic capacitive touch sensor, for example, a transparent conductive layer is provided on a glass plate or a transparent plastic film (especially PET film, polycarbonate film, cyclic olefin polymer film) transparent conductive film. The adhesive layer of the present invention is preferably bonded to the transparent conductive layer in a contact manner.

Examples of the transparent conductive layer include ITO film (indium tin oxide), ZnO, SnO, and CTO (cadmium tin oxide) thin film. In addition, the above-mentioned transparent conductive layer may be formed of silver, copper, CNT (carbon nanotube), etc. In addition, the above-mentioned transparent conductive layer can also use metal mesh sensors such as nanosilver wires and Ag/Cu. In addition, the above-mentioned touch sensor may also have traction wiring formed of thin film copper or silver paste at its end.

The optical laminated body may be provided with a cover member. The cover member is provided on the surface of the touch sensor opposite to the side provided with the image display device, and protects the touch sensor or the image display device in the optical laminate. Examples of the cover member include cover glass or plastic cover. The cover member may be bonded to a layer constituting the optical laminate such as a touch sensor via an adhesive layer. The above-mentioned adhesive layer can be the adhesive layer of the present invention, but since the function of suppressing the amplification of noise emitted by the image display device is not required, it can also be other adhesive layers. Furthermore, the optical laminate may have a polarizing film on the surface of the image display device (the surface having the touch sensor).

The above-mentioned optical laminate may be provided with a noise reduction layer (noise reduction film, etc.). From the viewpoint of the function of suppressing the amplification of noise emitted by the image display device, the noise reduction layer is preferably disposed between the touch sensor and the image display device. The above-mentioned noise reduction layer and the touch sensor, as well as the above-mentioned noise reduction layer and the image display device are respectively bonded through an adhesive layer (preferably the adhesive layer of the present invention). The above-mentioned noise reduction layer may be a single layer or multiple layers. When there are a plurality of noise reduction layers, the plurality of noise reduction layers may be layers with the same composition or thickness, or may be different layers.

1 to 3 show one embodiment of the optical laminate of the present invention. The optical laminated body 1 shown in FIG. 1 includes an image display device 5, a polarizing film 6 provided on the image display device 5, a touch sensor 41, a touch sensor 42, and a cover member 3 in this order. . The polarizing film 6 and the touch sensor 41 are bonded together through an adhesive layer (adhesive sheet) 21, and the touch sensor 41 and the touch sensor 42 are bonded together through an adhesive layer (adhesive sheet). 22 for fitting. Adhesive layers 21 and 22 are adhesive layers of the present invention. In addition, the touch sensor 42 and the cover member 3 are bonded together by the adhesive layer (adhesive sheet) 23 . The adhesive layer 23 is another adhesive layer.

The optical laminated body 1 shown in FIG. 2 includes an image display device 5, a polarizing film 6 provided on the image display device 5, a touch sensor 43, and a cover member 3 in this order. For example, the touch sensor 43 has the functions of both the touch sensors 41 and 42 in FIG. 1 . The polarizing film 6 and the touch sensor 43 are bonded together through the adhesive layer 21 . The adhesive layer 21 is the adhesive layer of the present invention. In addition, the touch sensor 43 and the cover member 3 are bonded by the adhesive layer 23 . The adhesive layer 23 is another adhesive layer.

The optical laminated body 1 shown in FIG. 3 includes an image display device 5, a polarizing film 6 provided on the image display device 5, a noise reduction layer 44, a touch sensor 43, and a cover member 3 in this order. The polarizing film 6 and the noise reduction layer 44 are bonded together through the adhesive layer 21 , and the noise reduction layer 44 and the touch sensor 43 are bonded together through the adhesive layer 22 . Adhesive layers 21 and 22 are adhesive layers of the present invention. In addition, the touch sensor 43 and the cover member 3 are bonded by the adhesive layer 23 . The adhesive layer 23 is another adhesive layer.

Furthermore, in FIGS. 1 to 3 , the polarizing film 6 does not need to be provided. In this case, the image display device 5 and the touch sensors 41 and 43 or the noise reduction layer 44 are bonded through the adhesive layer 21 .

[Millimeter wave antenna] A millimeter wave antenna can be obtained using the adhesive layer of the present invention. The millimeter-wave antenna equipped with the adhesive layer of the present invention is sometimes referred to as the "millimetre-wave antenna of the present invention." Examples of components constituting the millimeter wave antenna include a substrate (hereinafter, sometimes referred to as a "millimeter wave antenna") of an antenna element (hereinafter, sometimes referred to as a "millimeter wave antenna element") for transmitting and receiving millimeter waves. "Substrate").

The millimeter-wave antenna substrate can be exemplified by the plastic film illustrated and described as the above-mentioned substrate. Among them, from the viewpoint of being able to suppress the radiation loss of millimeter waves, materials with low dielectric constant and low dielectric loss are preferred, and materials with the trade name "ARTON" (cyclic olefin polymer, JSR Co., Ltd.) are particularly preferred. Cyclic olefin-based polymers such as "ZEONOR" (cyclic olefin-based polymer, manufactured by Nippon Zeon Co., Ltd.), trade name "ZEONOR".

From the perspective of suppressing millimeter wave radiation loss, the dielectric constant of the millimeter wave antenna substrate at 28 GHz and/or 60 GHz is preferably 2.0 to 5.0, more preferably 2.1 to 4.5, and further preferably 2.2 to 4.0. It is more preferably 2.2 to 3.5, still more preferably 2.2 to 3.4, still more preferably 2.2 to 3.3, still more preferably 2.2 to 3.2, still more preferably 2.2 to 3.1, and particularly preferably 2.2 to 3.0. Furthermore, from the viewpoint of suppressing the radiation loss of millimeter waves, the dielectric loss of the millimeter wave antenna substrate at 28 GHz and/or 60 GHz is preferably 0.0001~0.05, more preferably 0.001~0.02, and further preferably 0.002~ 0.019, more preferably 0.003～0.018, still more preferably 0.004～0.017, still more preferably 0.005～0.016, still more preferably 0.006～0.015, still more preferably 0.007～0.014, still more preferably 0.008～0.013, Furthermore, 0.009-0.012 is more preferable, and 0.01-0.011 is especially preferable.

The millimeter wave antenna substrate is preferably transparent. The total light transmittance (based on JIS K7361-1) of the millimeter wave antenna substrate in the visible light wavelength region is not particularly limited, but is preferably 85% or more, more preferably 88% or more, further preferably 89% or more, still more preferably It is 90% or more, more preferably 91% or more, especially 92% or more. In addition, the haze (based on JIS K7136) of the millimeter wave antenna substrate is not particularly limited, but is preferably 1.2% or less, more preferably 1.1% or less, further preferably 1.0% or less, further preferably 0.9% or less, especially The best value is less than 0.8%.

From the viewpoint of mounting millimeter wave antenna elements and suppressing millimeter wave radiation loss, the thickness of the millimeter wave antenna substrate is preferably 5 to 250 μm. Furthermore, the millimeter wave antenna substrate may have either a single layer or multiple layers. In addition, the surface of the millimeter wave antenna substrate may be appropriately subjected to known or commonly used surface treatments, such as physical treatments such as corona discharge treatment and plasma treatment, chemical treatments such as primer treatment, and coatings such as hard coating.

The millimeter-wave antenna element included in the millimeter-wave antenna substrate is not particularly limited as long as it can transmit and receive millimeter waves. From the perspective of efficiently receiving millimeter waves with portable communication devices such as smartphones, a phased array antenna can be preferably used. . By arranging multiple antenna elements in an array and controlling the phase of each antenna element, a phased array antenna can transmit and receive in a desired direction. That is, a phased array antenna can transmit or receive radio waves in a desired direction by electronically controlling (beam steering) the phase of each antenna element regardless of the direction of the antenna.

Known antennas can be used as millimeter wave antenna elements without particular limitation. For example, loop antenna structures, patch antenna structures, stacked patch antenna structures, patch antenna structures with parasitic elements, inverse F Antenna structures, slot antenna structures, planar inverted F antenna structures, monopole, dipole, helical antenna structures, Yagi (Yagi-Uda) antenna structures, surface integrated waveguide structures, and structures designed by these The antenna element is a resonant element formed by mixing etc. Different types of millimeter wave antenna elements can also be used for different combinations of frequency bands. From the viewpoint of efficiently receiving millimeter waves using portable communication devices such as smartphones, a phased array antenna in which patch antenna elements are arranged in an array is preferred.

The materials constituting the millimeter wave antenna elements are not particularly limited, for example, titanium, silicon, niobium, indium, zinc, tin, gold, silver, copper, aluminum, cobalt, chromium, nickel, lead, iron, palladium, platinum , tungsten, zirconium, tantalum, hafnium and other metals; ITO (indium and tin oxide), zinc oxide, tin oxide and other metal oxides. Furthermore, those containing two or more of these metals or metal oxides, or an alloy containing these metals as a main component can also be mentioned. Among them, from the viewpoint of electrical conductivity, silver, copper, and ITO are preferable, and from the viewpoint of transparency and visibility, ITO is more preferable. That is, it is particularly preferable that the above-mentioned millimeter wave antenna element contains ITO. In addition, when the antenna element contains metal such as silver or copper, in order to hide the antenna element and prevent the reduction of visibility due to reflection of the metal, it is also possible to form a film of nitride, oxide, sulfide, etc. of the metal. Implement blackening treatment.

In addition, the millimeter wave antenna substrate may also be provided with a transmission line path for transmitting signals transmitted and received by the millimeter wave antenna element to the transceiver circuit. Transmission line paths may include coaxial cable paths, microstrip transmission lines, strip transmission lines, edge-coupled microstrip transmission lines, edge-coupled strip transmission lines, waveguide structures (e.g., coplanar waveguides or grounded coaxial Surface waveguide), transmission lines formed by combinations of these types of transmission lines, etc. The material constituting the transmission line path is not particularly limited, and the material constituting the millimeter wave antenna element can be used.

An example of a member constituting the millimeter wave antenna is a cover member laminated on the millimeter wave antenna substrate in order to protect the millimeter wave antenna elements arranged on the millimeter wave antenna substrate. The cover member is not particularly limited, and for example, an optical film such as glass or plastic film can be used. Examples of materials for plastic films include polyester resins such as polyethylene terephthalate (PET), (meth)acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, and tricarbonate resins. Acetyl cellulose (TAC), polystyrene, polyarylate, polyimide, transparent polyimide, polyvinyl chloride, polyvinyl acetate, fluorine resin, polyethylene, polypropylene, ethylene-propylene copolymer Cyclic olefin-based polymers under the trade name "ARTON" (cyclic olefin-based polymer, manufactured by JSR Co., Ltd.), brand name "ZEONOR" (cyclic olefin-based polymer, manufactured by Nippon Zeon Co., Ltd.), etc. Plastic material. Furthermore, only one type of plastic material can be used, or two or more types of plastic materials can be used.

From the viewpoint of suppressing millimeter wave radiation loss, the dielectric constant of the cover member at 28 GHz and/or 60 GHz is preferably 2.0 to 5.0, more preferably 2.1 to 4.5, and further preferably 2.2 to 4.0. It is more preferably 2.2 to 3.5, still more preferably 2.2 to 3.4, still more preferably 2.2 to 3.3, still more preferably 2.2 to 3.2, still more preferably 2.2 to 3.1, and particularly preferably 2.2 to 3.0. Furthermore, from the viewpoint of suppressing the radiation loss of millimeter waves, the dielectric loss of the cover member at 28 GHz and/or 60 GHz is preferably 0.0001 to 0.05, more preferably 0.001 to 0.02, and further preferably 0.002 to 0.002. 0.019, more preferably 0.003～0.018, still more preferably 0.004～0.017, still more preferably 0.005～0.016, still more preferably 0.006～0.015, still more preferably 0.007～0.014, still more preferably 0.008～0.013, Furthermore, 0.009-0.012 is more preferable, and 0.01-0.011 is especially preferable.

The above-mentioned cover member is preferably transparent. The total light transmittance (based on JIS K7361-1) of the cover member in the visible light wavelength range is not particularly limited, but is preferably 85% or more, more preferably 88% or more, further preferably 89% or more, still more preferably It is 90% or more, more preferably 91% or more, especially 92% or more. In addition, the haze (based on JIS K7136) of the cover member is not particularly limited, but it is preferably 1.2% or less, more preferably 1.1% or less, still more preferably 1.0% or less, still more preferably 0.9% or less, and particularly preferably is less than 0.8%.

From the viewpoint of suppressing radiation loss of millimeter waves, the thickness of the cover member is preferably 0.025 to 1.5 mm. Furthermore, the cover member may have either a single layer or a plurality of layers. In addition, the surface of the cover member may be appropriately subjected to known or commonly used surface treatments, such as physical treatments such as corona discharge treatment and plasma treatment, chemical treatments such as primer treatment, and coatings such as hard coating.

The adhesive sheet of the present invention can be well used to manufacture millimeter wave antennas used in portable communication equipment. Examples of the above-mentioned portable communication devices include: mobile phones, PHS (Personal Handy-phone System), smart phones, tablets (tablet computers), mobile computers (mobile PCs), and portable information terminals (PDA). )wait.

The millimeter-wave antenna may also have components other than the above-mentioned millimeter-wave antenna substrate, cover member, and adhesive sheet, such as a polarizing plate, a wavelength plate, a phase difference plate, an optical compensation film, a brightness enhancement film, a light guide plate, a reflective Film, anti-reflective film, hard coat film, transparent conductive film, design film, decorative film, surface protection board, lens, color filter, transparent substrate, or image display panel (such as liquid crystal display panel, organic EL panels, plasma display panels, etc.), etc. The image display panel may also have a touch sensor.

Millimeter wave antennas can be placed anywhere on the portable communication device. Specifically, they can be placed on the front, back, or side of the portable communication device. Furthermore, the front of the portable communication device refers to the surface facing the user when using the portable communication device, for example, it is equivalent to the surface with the display panel, and the back and side are equivalent to the casing. Furthermore, a display panel refers to a structure including at least a lens (especially a glass lens) and a touch panel.

The size (width) of the millimeter wave antenna is also not limited, and it can be formed on the entire surface of each surface of the portable communication device, or it can be arranged on a part. In addition, the shape of the millimeter wave antenna is not particularly limited, and may be, for example, quadrangular, circular, or wire-shaped. In addition, it can also be arranged in a frame shape. Furthermore, the number of millimeter wave antennas arranged in the portable communication device is not limited. It can be one, or a plurality of antennas can be arranged at any position. When multiple millimeter wave antennas are configured, the sizes (widths) can be the same or different. In order to improve visibility, dummy patterns without millimeter wave antennas can also be placed in areas of the portable communication device that are not equipped with millimeter wave antennas.

The above-mentioned millimeter wave antenna is a millimeter wave antenna having at least the adhesive sheet of the present invention and a substrate. The above-mentioned substrate has an antenna element (millimeter wave antenna element) on one side, as long as the above-mentioned substrate (millimeter wave antenna substrate) has the above-mentioned antenna element. It only suffices that the adhesive sheet of the present invention is affixed to one side, and other aspects are not particularly limited. Furthermore, the adhesive sheet of the present invention in the above-mentioned millimeter wave antenna is an adhesive sheet during use, and therefore does not have a release liner.

The above-mentioned millimeter wave antenna is preferably a millimeter wave antenna substrate and other optical components (which may or may not have the adhesive sheet of the present invention). From the perspective of further suppressing the radiation loss of millimeter waves, it is preferred that It has a state in which the adhesive sheet of the present invention is laminated together. In addition, the number of the other optical members mentioned above may be singular or plural.

In the above situation, the method of bonding the millimeter wave antenna and the other optical components mentioned above is not particularly limited. Examples include: (1) The millimeter wave antenna substrate and the other optical components mentioned above are bonded through the adhesive sheet of the present invention. The manner in which the components are bonded together; (2) The manner in which the adhesive sheet of the present invention, which contains or constitutes the millimeter wave antenna substrate, is bonded to the other optical components mentioned above; (3) The millimeter wave antenna is bonded through the adhesive sheet of the present invention. How the substrate is bonded to components other than the millimeter wave antenna substrate; (4) How the adhesive sheet of the present invention, which includes or constitutes the millimeter wave antenna substrate, is bonded to components other than the millimeter wave antenna substrate, etc. Furthermore, in the aspect (2) above, the adhesive sheet of the present invention is preferably a double-sided adhesive sheet whose base material is a millimeter wave antenna substrate.

Next, preferred embodiments of the above-mentioned millimeter wave antenna will be described with reference to the drawings. FIG. 4 shows a millimeter wave antenna 10, which at least includes an adhesive sheet (adhesive layer) 11 and a substrate serving as a millimeter wave antenna substrate 12. The millimeter wave antenna substrate 12 has a millimeter wave antenna element 13 on one side, and the adhesive sheet 11 It is attached to the surface of the millimeter wave antenna substrate 12 on the side with the millimeter wave antenna element 13 .

FIG. 5 illustrates a millimeter wave antenna 10 including a cover member 14 , an adhesive sheet 11 , and a millimeter wave antenna substrate 12 that are in sequential contact with each other. The millimeter wave antenna substrate 12 is provided with the millimeter wave antenna element 13 on the surface of the adhesive sheet 11 , and the adhesive sheet 11 is attached to the surface of the millimeter wave antenna substrate 12 on the side of the millimeter wave antenna element 13 . The cover member 14 is preferably glass. In terms of low dielectric constant and low dielectric loss, the millimeter wave antenna substrate 12 is preferably COP, and the millimeter wave antenna element 13 is preferably copper, silver, or ITO.

FIG. 6 shows a case including a cover member 14, an adhesive sheet (adhesive layer) 11a, a millimeter-wave antenna substrate 12, an adhesive sheet (adhesive layer) 11b, and an image display panel 15 that are in sequential contact with each other. Millimeter wave antenna 10. The millimeter wave antenna substrate 12 is provided with the millimeter wave antenna element 13 on the surface of the adhesive sheet 11a, and the adhesive sheet 11a is attached to the millimeter wave antenna element 13 side of the millimeter wave antenna substrate 12. The cover member 14 is preferably made of glass, the millimeter-wave antenna substrate 12 is preferably COP from the viewpoint of low dielectric constant and low dielectric loss, and the millimeter-wave antenna element 13 is preferably made from the viewpoint of transparency and visibility. Preferably, it is silver or copper that has been blackened by a film of ITO, nitride, oxide, sulfide or the like. The adhesive sheet 11b may be the adhesive sheet of the present invention, or may not be the adhesive sheet of the present invention, but is preferably the adhesive sheet of the present invention. The image display panel 15 may also have a touch sensor (not shown).

In the millimeter wave antenna 10 shown in Figures 4 to 6, the adhesive sheets 11, 11a, preferably and the adhesive sheet 11b include the adhesive layer of the present invention with low dielectric constant and low dielectric loss in the high frequency band. , so the radiation loss of millimeter waves is suppressed, and millimeter wave communications can be carried out efficiently. Furthermore, since millimeter wave communication can be performed efficiently, the area of the antenna can be reduced and the antenna can be miniaturized.

According to the adhesive composition of the present invention, an adhesive layer with a lower dielectric constant can be formed. Therefore, for example, by using the above-mentioned adhesive layer for bonding the touch sensor and the image display device, the noise emitted by the image display device can be prevented from being easily transmitted to the touch sensor. Furthermore, for example, by using the above adhesive layer as an adhesive layer bonded to a millimeter wave antenna substrate used in a millimeter wave antenna, the radiation loss of millimeter waves can be suppressed.

The embodiments described above are described to facilitate understanding of the present invention and are not described to limit the present invention. Example

The following examples are given to illustrate the present invention in more detail, but the present invention is not limited by these examples.

Synthesis example 1 (Synthesis of polyester resin (A1)) A stirrer, a thermometer, and a vacuum pump were installed in a three-necked separable flask, and 65 g of bis(2-hydroxyethyl) terephthalate (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight: 254) and dimer alcohol ( Product name "Pripol 2033", manufactured by Croda Co., Ltd., molecular weight 537, carbon number 36, number of heteroatoms other than diol and hydroxyl group: 0) 140 g, titanium tetra-n-butoxide as a catalyst (product name "ORGATIX TA-21 ”, manufactured by Matsumoto Fine Chemical Co., Ltd.) 0.2 g, and the temperature was raised to 180°C while stirring under a nitrogen atmosphere. After reaching 180°C, the temperature was raised to 210°C while stirring in a reduced pressure atmosphere (2.0 kPa or less) and maintained at this temperature. The reaction was continued for about 4 hours to obtain a polyester resin (A1). The polyester resin (A1) has a weight average molecular weight (Mw) of 41,000 and a glass transition temperature (Tg) of -20°C.

Synthesis example 2 (Synthesis of polyester resin (A2)) A stirrer, a thermometer, and a vacuum pump were installed in a three-necked separable flask, and 65 g of bis(2-hydroxyethyl) terephthalate (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight: 254) and dimer alcohol ( Product name "Pripol 2033", manufactured by Croda Co., Ltd., molecular weight 537, carbon number 36, number of heteroatoms other than diol and hydroxyl group: 0) 140 g, titanium tetra-n-butoxide as catalyst (product name "ORGATIX TA-21 ”, manufactured by Matsumoto Fine Chemical Co., Ltd.) 0.05 g, and the temperature was raised to 180°C while stirring under a nitrogen atmosphere. After reaching 180°C, the temperature was raised to 210°C while stirring in a reduced pressure atmosphere (2.0 kPa or less) and maintained at this temperature. The reaction was continued for about 4 hours to obtain a polyester-based resin (A2). The polyester resin (A2) has an Mw of 59,000 and a Tg of -20°C.

Synthesis example 3 (Synthesis of polyester resin (A3)) A stirrer, a thermometer, and a vacuum pump were installed in a three-necked separable flask, and 60 g of bis(2-hydroxyethyl) terephthalate (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight: 254) and dimer alcohol ( Product name "Pripol 2033", manufactured by Croda Co., Ltd., molecular weight 537, carbon number 36, number of heteroatoms other than diol and hydroxyl group (0) 122.9 g, polytetramethylene glycol (manufactured by Mitsubishi Chemical Co., Ltd., molecular weight 2000 ) 23.6 g and 0.2 g of titanium tetra-n-butoxide as a catalyst (product name "ORGATIX TA-21", manufactured by Matsumoto Fine Chemical Co., Ltd.), and the temperature was raised to 180°C while stirring in a nitrogen atmosphere. After reaching 180°C, the temperature was raised to 210°C while stirring in a reduced pressure atmosphere (2.0 kPa or less) and maintained at this temperature. The reaction was continued for about 4 hours to obtain a polyester resin (A3). The polyester resin (A3) has an Mw of 43,000 and a Tg of -29°C.

Synthesis example 4 (Synthesis of polyester resin (A4)) Attach a stirrer, thermometer, and vacuum pump to a three-necked separable flask, and add dimer acid (product name "Pripol 1009", manufactured by Croda Co., Ltd., molecular weight 567, carbon number 36, dicarboxylic acid, and heteroatoms other than carboxyl groups). number is 0) 97.8 g, dimer (product name "Pripol 2033", manufactured by Croda Co., Ltd., molecular weight 537, carbon number 36, number of heteroatoms other than diol and hydroxyl group is 0) 102.2 g, dioxide as a catalyst 0.2 g of butyltin (manufactured by Kanto Chemical Co., Ltd.) was heated to 200°C with stirring under a reduced pressure atmosphere (2.0 kPa or less) and maintained at this temperature. The reaction was continued for about 5 hours to obtain a polyester-based resin (A4). The polyester resin (A4) has an Mw of 30,000 and a Tg of -43°C.

Synthesis example 5 (Synthesis of polyester resin (A5)) A stirrer, thermometer, nitrogen tube, and water separation tube were installed in a four-neck detachable flask, and 100 g of ethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 62) and dimer acid (product name "Pripol" were added thereto) 1009", Croda Co., Ltd., molecular weight 567, carbon number 36, dicarboxylic acid, heteroatoms other than carboxyl group (0) 700 g, terephthalic acid (Tokyo Chemical Industry Co., Ltd., molecular weight 166) 63 g, 0.46 g of di-n-butyltin oxide (manufactured by Kishida Chemical Co., Ltd., molecular weight 249) as a polymerization catalyst and 40 g of xylene as a reaction water discharge solvent were heated to 180° C. while stirring in a nitrogen atmosphere, and the temperature was maintained. After a while, the reaction water was observed to flow out and separate, and the reaction began. The reaction was continued for about 24 hours to obtain a polyester resin (A5). The polyester resin (A5) has an Mw of 100,000 and a Tg of -33°C.

Example 1 To 100 parts by mass of the polyester resin (A1), 3 parts by mass of hexamethylene diisocyanate-modified isocyanurate (trade name "Coronate HX", manufactured by Tosoh Co., Ltd.) was added as the cross-linking agent (B1). , 0.03 parts by mass of an organic zirconium compound (trade name "ORGATIX ZC-162", manufactured by Matsumoto Fine Chemical Co., Ltd.) as a cross-linking catalyst, and toluene to prepare an adhesive composition (adhesive solution). The adhesive solution was applied to a peel-treated polyethylene terephthalate (PET) film (trade name "DIAFOIL MRF♯38", manufactured by Mitsubishi Chemical Co., Ltd. so that the thickness after drying became 25 μm). ), and dry at 120°C for 3 minutes to obtain an adhesive layer. Thereafter, the above-mentioned adhesive layer was bonded to the peel-treated surface of a peel-treated PET film (trade name "DIAFOIL MRE♯38", manufactured by Mitsubishi Chemical Co., Ltd.), and then left at 60° C. for 3 days to prepare an example. 1. Adhesive sheet without base material.

Example 2 Polyester resin (A2) was used instead of polyester resin (A1), and the usage amount of the crosslinking agent was changed to 2 parts by mass relative to 100 parts by mass of polyester resin (A2). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 2 were produced in the same manner as Example 1.

Example 3 Polyester-based resin (A2) is used instead of polyester-based resin (A1). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 3 were produced in the same manner as Example 1.

Example 4 To 100 parts by mass of polyester resin (A2), 3 parts by mass of bifunctional isocyanate (trade name "Duranate D101", manufactured by Asahi Kasei Co., Ltd.) as a cross-linking agent (B2) and organic zirconium as a cross-linking catalyst were added 0.03 parts by mass of a compound (trade name "ORGATIX ZC-162", manufactured by Matsumoto Fine Chemical Co., Ltd.) and toluene were used to prepare an adhesive composition (adhesive solution). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 4 were produced in the same manner as Example 1.

Example 5 Polyester-based resin (A3) is used instead of polyester-based resin (A1). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 5 were produced in the same manner as Example 1.

Example 6 Polyester-based resin (A4) is used instead of polyester-based resin (A1). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 6 were produced in the same manner as Example 1.

Example 7 Polyester resin (A4) was used instead of polyester resin (A1), and the usage amount of the crosslinking agent was changed to 4 parts by mass relative to 100 parts by mass of polyester resin (A4). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 7 were produced in the same manner as Example 1.

Example 8 Polyester-based resin (A5) is used instead of polyester-based resin (A1). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 8 were produced in the same manner as Example 1.

Example 9 To 100 parts by mass of polyester resin (A1), 3 parts by mass of bifunctional isocyanate (trade name "Duranate D101", manufactured by Asahi Kasei Co., Ltd.) as a cross-linking agent (B2) and organic zirconium as a cross-linking catalyst were added Compound (trade name "ORGATIX ZC-162", manufactured by Matsumoto Fine Chemical Co., Ltd.) 0.03 parts by mass, hydrogenated terpene phenol resin ("YS POLYSTER U115", manufactured by Yasuhara Chemical Co., Ltd.) as the tackifier resin (C1) 20 parts by mass, and toluene to prepare an adhesive composition (adhesive solution). Except for this, the substrate-less adhesive sheet of Example 9 was produced in the same manner as Example 1.

Example 10 Rosin ester resin ("Pine Crystal KE-359", manufactured by Arakawa Chemical Co., Ltd.) as the tackifier resin (C2) was used instead of the tackifier resin (C1). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 10 were produced in the same manner as Example 9.

Example 11 Rosin ester resin ("Pine Crystal KE-311", manufactured by Arakawa Chemical Co., Ltd.) as the tackifier resin (C3) was used instead of the tackifier resin (C1). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 11 were produced in the same manner as Example 9.

Example 12 The usage amount of the tackifier resin (C3) was changed to 40 parts by mass relative to 100 parts by mass of the polyester-based resin (A1). Except for this, the adhesive composition and substrate-free adhesive sheet of Example 12 were produced in the same manner as Example 11.

＜Evaluation＞ The evaluation methods of the polyester-based resin produced in the synthesis examples and the adhesive sheet produced in the examples are shown below.

(1) Weight average molecular weight (Mw) The weight average molecular weight (Mw) of the polyester resin is a standard polystyrene-converted value obtained by GPC (gel permeation chromatography). The device name "HLC-8320 gPC" (column: TSKgelGMH-H(S), manufactured by Tosoh Co., Ltd.) was used as the GPC device, and the following conditions were followed. Column: TSKgelGMH-H(S) Tube string temperature: 40℃ Eluate: THF (add 0.1 mass% amine component) Flow rate: 0.5 mL/min Injection volume: 100 μL Detector: Differential Refractometer (RI) Standard sample: polystyrene (PS)

(2)Dielectric constant and dielectric loss The adhesive layer obtained in the example (made by peeling off the silicone-treated PET film from the adhesive sheet) was sandwiched between the copper foil and the electrode, and the dielectric constant and the dielectric constant at a frequency of 100 kHz were measured using the following device. Dielectric loss. In the measurement, three samples are prepared, and the average value of the measured values of the three samples is used as the dielectric constant and dielectric loss. In addition, the relative dielectric constant of the adhesive layer at a frequency of 100 kHz was measured under the following conditions based on JIS K6911. Measurement method: capacitance method (device: Agilent Technologies 4294A Precision Impedance Analyzer) Electrode composition: 12.1 mmΦ, 0.5 mm thick aluminum plate Counter electrode: 3 oz copper plate Measurement environment: 23±1℃, 52±1%RH

(3) Total light transmittance and haze From the adhesive sheet obtained in the Example, the PET film that had been subjected to the peeling process was peeled off, and the exposed adhesive surface was bonded to a glass slide (trade name "White Polishing No. 1" (thickness 0.8 to 1.0 mm, total light transmittance 92%, haze 0.2%, b ^* 0.15), manufactured by Shounami Glass Industry Co., Ltd.) and subjected to autoclave treatment (50°C, 0.5 MPa, 15 minutes) . After the treatment, another PET film that has been subjected to the peeling treatment is peeled off to prepare a test piece having a layer structure of [adhesive sheet (adhesive layer)/glass slide]. Use a haze meter (device name "HSP-150Vis", manufactured by Murakami Color Laboratory Co., Ltd.) to measure the total light transmittance of the above test piece in the visible light region in an environment of 23±1°C and 52±1%RH. and haze. Three samples were prepared for each sample, and the average of the measured values of the three samples was set as the total light transmittance and haze in the visible light region.

(4) Hue (b ^* ) Peel off the PET film that has been subjected to the peeling process from the adhesive sheet obtained in the Example, and bond the exposed adhesive surface to a glass slide (trade name "White Polished No. 1") (thickness 0.8 to 1.0 mm, total light transmittance 92%, haze 0.2%, b ^* 0.15), manufactured by Shounami Glass Industry Co., Ltd.) and subjected to autoclave treatment (50°C, 0.5 MPa, 15 minutes). After the treatment, another PET film that has been subjected to the peeling treatment is peeled off to prepare a test piece having a layer structure of [adhesive sheet (adhesive layer)/glass slide]. Use a UV-visible-near-infrared spectrophotometer (device name "UH4150", manufactured by Hitachi High-Tech Science Co., Ltd.) to measure b in the visible light range of the above test piece in an environment of 23±1°C and 52±1%RH. ^＊ . Three samples were prepared for each sample, and the average of the measured values of the three samples was set as b ^* in the visible light region.

(5)180° peel adhesion A sheet piece with a length of 100 mm and a width of 20 mm was cut out from the adhesive sheet obtained in the example. Then, a PET film that has been peeled off of the adhesive sheet is attached (backing) to the exposed adhesive surface (trade name "Lumirror S-10♯25", manufactured by Toray Co., Ltd.). Next, another PET film that had been peeled was peeled off, and it was crimped to a glass plate as a test plate (trade name "Soda Lime Glass ♯0050", Matsunami Glass under the conditions of one round trip with a 2 kg roller. Manufactured by Industrial Co., Ltd.) and prepare a sample composed of [test plate/adhesive layer/PET film]. The obtained sample was subjected to autoclave treatment (50°C, 0.5 MPa, 15 minutes), and then left to cool for 30 minutes in an atmosphere of 23°C and 50% RH. After leaving to cool, use a tensile testing machine (device name "EZ Test/EZ-S", manufactured by Shimadzu Corporation), in accordance with JIS Z0237 in an atmosphere of 23°C and 50%RH at a tensile speed of 300 mm/ Minutes, peel off the adhesive sheet (adhesive layer/PET film) from the test plate at a peeling angle of 180°, and measure the 180° peeling adhesive force (N/20 mm).

(6)Tg and storage elastic modulus The adhesive layers obtained in the examples were laminated and die-cut to prepare disk-shaped test pieces with a thickness of 2 mm and a diameter of 8 mm. The specimen was clamped using parallel plates for shear testing, and the loss elastic modulus G' was measured using a dynamic viscoelasticity measuring device (device name "ARES-G2", manufactured by TA Instruments) under the measurement conditions described below. 'and store the elastic modulus G'. The peak value of the ratio of the loss elastic modulus to the storage elastic modulus (G''/G') = Tanδ is read as the Tg of the adhesive layer. ・Measurement: Cut mode ・Temperature range: -50℃～150℃ ・Heating rate: 5℃/min ・Frequency: 1 Hz

(7) Gel fraction Take about 0.1 g of the adhesive layer obtained in the example, wrap it with a porous tetrafluoroethylene sheet with an average pore size of 0.2 μm (trade name "NTF1122", manufactured by Nitto Denko Co., Ltd.), and tie it with a kite string. The weight at this time was measured and this weight was regarded as the weight before immersion (Z). Furthermore, the weight before immersion is the total weight of the adhesive layer (the adhesive layer adopted above), the PTFE sheet, and the kite string. Moreover, the total weight of the tetrafluoroethylene sheet and the kite string was also measured in advance, and this weight was set as the packaging weight (Y). Secondly, put the adhesive layer wrapped with tetrafluoroethylene sheet and tied with kite string (called "sample") into a 50 ml container filled with ethyl acetate or toluene, and let it stand at 23°C for 7 days. Thereafter, the sample (after treatment with ethyl acetate or toluene) was taken out from the container, moved to an aluminum cup, dried in a dryer at 130°C for 2 hours to remove the ethyl acetate or toluene, and then the weight was measured and the weight was Let it be the weight after immersion (X). Then, the gel fraction was calculated from the following equation. Gel fraction [%(weight%)]=(X-Y)/(Z-Y)×100

[Table 1] (Table 1) Adhesive composition Dielectric constant 100 kHz Dielectric loss 100 kHz Tg [℃] Total light transmittance [%] Haze[%] b* 180° peel adhesion [N/20 mm] Storage elastic modulus 23℃ [MPa] Gel fraction [%] Polyester resin Cross-linking agent Adhesion imparting resin A1 A2 A3 A4 A5 B1 B2 C1 C2 C3 Example 1 100 3 3.0 0.06 -20 92.0 1.11 0.23 4.3 0.3 72 Example 2 100 2 3.0 0.07 -20 91.9 0.73 0.26 3.2 0.3 64 Example 3 100 3 3.0 0.07 -20 91.9 0.85 0.29 3.1 0.5 76 Example 4 100 3 3.0 0.07 -20 91.9 0.73 0.26 6.8 0.4 48 Example 5 100 3 3.1 0.05 -29 92.0 0.54 0.22 8.8 0.2 36 Example 6 100 3 2.5 0.02 -43 92.2 0.49 0.29 5.1 0.1 61 Example 7 100 4 2.5 0.02 -43 92.1 0.75 0.23 2.2 0.2 81 Example 8 100 3 2.9 0.02 -33 91.7 1.17 0.22 6.2 0.2 58 Example 9 100 3 20 2.7 0.05 -9 91.0 0.83 0.26 5.7 0.4 25 Example 10 100 3 20 2.9 0.06 -8 91.0 0.36 0.19 8.0 0.5 4 Example 11 100 3 20 2.9 0.06 -10 91.0 0.63 0.22 6.8 0.4 34 Example 12 100 3 40 2.7 0.05 -1 91.9 0.60 0.20 7.8 0.4 20

Modifications of the present invention will be described below. [Additional Note 1] An adhesive composition containing a polyester resin containing a structural unit derived from a compound having 20 or more carbon atoms and having two or more functional groups capable of forming an ester bond, and When the adhesive layer is formed in the adhesive composition, the dielectric constant at a frequency of 100 kHz is 4.0 or less. [Supplement 2] The adhesive composition as described in Appendix 1 has a dielectric loss of 0.0001 to 0.15 at a frequency of 100 kHz when the adhesive layer is formed. [Supplement 3] The adhesive composition according to Appendix 1 or 2, wherein the glass transition temperature of the polyester resin is 0° C. or lower. [Appendix 4] An adhesive layer formed from the adhesive composition described in any one of Appendices 1 to 3. [Appendix 5] An adhesive sheet having an adhesive layer as described in Appendix 4.

1: Optical laminated body 3: Cover component 5:Image display device 6:Polarizing film 10: Millimeter wave antenna 11: Adhesive sheet (adhesive layer) 11a: Adhesive sheet (adhesive layer) 11b: Adhesive sheet (adhesive layer) 12: Millimeter wave antenna substrate 13: Millimeter wave antenna elements 14:Cover component 15:Image display panel 21: Adhesive layer (adhesive sheet) 22: Adhesive layer (adhesive sheet) 23: Adhesive layer (adhesive sheet) 41:Touch sensor 42:Touch sensor 43:Touch sensor 44: Noise reduction layer

FIG. 1 is a schematic diagram (cross-sectional view) showing one embodiment of the optical laminate of the present invention. FIG. 2 is a schematic diagram (cross-sectional view) showing another embodiment of the optical laminate of the present invention. FIG. 3 is a schematic diagram (cross-sectional view) showing another embodiment of the optical laminate of the present invention. FIG. 4 is a schematic diagram (cross-sectional view) showing one embodiment of the millimeter wave antenna of the present invention. FIG. 5 is a schematic diagram (cross-sectional view) showing another embodiment of the millimeter wave antenna of the present invention. FIG. 6 is a schematic diagram (cross-sectional view) showing another embodiment of the millimeter wave antenna of the present invention.

1: Optical laminated body

3: Cover component

5:Image display device

6:Polarizing film

21: Adhesive layer (adhesive sheet)

22: Adhesive layer (adhesive sheet)

23: Adhesive layer (adhesive sheet)

41:Touch sensor

42:Touch sensor

Claims (5)

An adhesive composition comprising a polyester resin containing a structural unit derived from a compound having 20 or more carbon atoms and having two or more functional groups capable of forming an ester bond, and When the adhesive layer is formed in the adhesive composition, the dielectric constant at a frequency of 100 kHz is 4.0 or less. For example, the adhesive composition of claim 1 has a dielectric loss of 0.0001 to 0.15 at a frequency of 100 kHz when the adhesive layer is formed. The adhesive composition of claim 1, wherein the glass transition temperature of the polyester resin is below 0°C. An adhesive layer formed by the adhesive composition according to any one of claims 1 to 3. An adhesive sheet having an adhesive layer as claimed in claim 4.

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