JP6091202B2 - Substrate-less double-sided adhesive sheet - Google Patents

Description

  The present invention relates to a substrate-less double-sided pressure-sensitive adhesive sheet, which has an antistatic property, a release property, an oligomer sealing property, a good coating appearance, and has a good releasability without generating a peeling charge when the release film is peeled off. It can be peeled off, and after application of the adhesive, after the release film is bonded, the fluctuation in peeling to the adhesive layer is small, and migration and precipitation of the oligomer to the adhesive layer is as small as possible. The present invention relates to a substrate-less double-sided pressure-sensitive adhesive sheet suitable for various uses to be bonded via an adhesive layer, such as for producing a capacitive touch panel.

  Conventionally, various pressure-sensitive adhesive sheets for surface bonding between objects are known, and one example of the pressure-sensitive adhesive sheet is a base material-less double-sided pressure-sensitive adhesive sheet. The substrate-less double-sided PSA sheet consists of a laminate structure in which a light release film with a relatively low peel strength and a heavy release film with a relatively high peel strength are laminated on both sides of an adhesive layer. After removing, the double-sided pressure-sensitive adhesive sheet becomes only the pressure-sensitive adhesive layer having no supporting substrate.

  As a method of using a substrate-less double-sided pressure-sensitive adhesive sheet, first the light release film is peeled off, and one surface of the exposed adhesive layer is bonded to the object surface of the other side to be bonded, and after that adhesion, the heavy release film is further peeled off The other surface of the exposed pressure-sensitive adhesive layer is bonded to a different object surface, whereby the processing step in which the objects are surface-bonded is exemplified.

  In recent years, the substrate-less double-sided pressure-sensitive adhesive sheet has attracted attention because of its good workability, and its applications are expanding. It is also used for members for various optical applications such as mobile phones. In particular, a capacitive touch panel is rapidly expanding its application as an information terminal by a multi-touch operation in which a screen operation is performed with two fingers. Capacitive touch panels tend to have a thicker printing step than the resistive film method, and therefore a proposal has been made to eliminate the printing step by thickening the adhesive layer. When the pressure-sensitive adhesive layer is made thicker, when the release film is peeled off, a part of the pressure-sensitive adhesive layer adheres to the release film, or bubbles are mixed into the pressure-sensitive adhesive layer of the part transferred to the release film. There was a case where a malfunction occurred. Therefore, when using a substrateless double-sided pressure-sensitive adhesive sheet for optical applications, not only the substrateless double-sided pressure-sensitive adhesive sheet but also the release film to be combined is more stringent than before, and a release film with higher quality is required. The situation is needed.

  On the other hand, when using a release film, peeling electrification may occur when it is peeled off from the pressure-sensitive adhesive layer, and as a result, defects such as product defects due to adhesion or entrapment of foreign substances etc. occur at the processing site. There was a case. For this reason, it is not always sufficient to take antistatic measures only by handling facilities in the manufacturing process, and there has been a strong demand for antistatic treatment from the release film itself. Furthermore, in a release film provided with a heavy release type release layer, there was a tendency for heavy release when peeled after a state of being bonded to an adhesive layer for a long time. As in the present invention, in an application where a release film is bonded through an adhesive layer, when the ratio of the peeling force is out of the desired range, it is difficult to peel off in a scene that originally needs to be peeled off. May cause problems such as

JP 2011-189589 A JP 2011-245739 A JP 2011-224896 A JP 2011-224904 A JP2012-25030A JP 2012-184327 A JP 2012-207166 A

  The present invention has been made in view of the above circumstances, and the problem to be solved is, for example, as an electrostatic capacitance type touch panel member, which has an excellent antistatic property and releasability, and is encapsulated in the release film itself. The present invention provides a baseless double-sided pressure-sensitive adhesive sheet having a stopping performance.

  As a result of intensive studies in view of the above situation, the present inventors have found that according to the base material-less double-sided pressure-sensitive adhesive sheet having a specific configuration, the above problems can be easily solved, and the present invention has been completed. .

That is, the gist of the present invention is as follows.
It is a substrate-less double-sided pressure-sensitive adhesive sheet in which release films with different peeling forces are laminated on both sides of the pressure-sensitive adhesive layer, and both release films are released onto the coating layer of the polyester film having a coating layer. The coating layer has the following (A) to (C), the following (A) is 1% by weight to 40% by weight and the following (B) with respect to all nonvolatile components in the coating solution. In a substrate-less double-sided pressure-sensitive adhesive sheet, wherein the following (C) is contained in a range of more than 0% by weight and 20 % by weight or less.
Conductive compound (A): a polymer made of thiophene or a thiophene derivative doped with another anion compound, or a compound made of thiophene or a thiophene derivative and having an anionic group and a self-doped polymer -Binder polymer (B): Polyurethane resin whose polyol component is a polyester polyol-Component (C): glycerin (C1), polyglycerin (C2), glycerin or selected from the group of alkylene oxide adducts (C3) to polyglycerin One or more compounds or derivatives thereof

  The present invention relates to a substrate-less double-sided pressure-sensitive adhesive sheet, and a release film as a constituent material has antistatic properties, good release properties and oligomer sealing performance, and is used, for example, in a capacitive touch panel. It is suitable as a substrate-less double-sided pressure-sensitive adhesive sheet, and its industrial value is high.

It is typical sectional drawing which shows the base material-less double-sided adhesive sheet which concerns on embodiment of this invention.

  In the present invention, the polyester film constituting the first and second release films may have a single-layer structure or a laminated structure. For example, the polyester film exceeds the gist of the present invention in addition to a two-layer or three-layer structure. As long as there is not, it may be a multilayer of four layers or more, and is not particularly limited.

  The polyester used for the polyester film in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyester includes polyethylene terephthalate (PET) and the like. On the other hand, examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (eg, P-oxybenzoic acid). 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, is mentioned. In any case, the polyester referred to in the present invention refers to a polyester that is usually 60 mol% or more, preferably 80 mol% or more of polyethylene terephthalate or the like which is an ethylene terephthalate unit.

  In the present invention, it is preferable to blend particles in the polyester layer mainly for the purpose of imparting slipperiness. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples of the particles include magnesium, kaolin, aluminum oxide, and titanium oxide. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, it is possible to use precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed during the polyester production process.

  On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

  Moreover, the average particle diameter of the particle | grains to be used is 0.01-3 micrometers normally, Preferably it is the range of 0.01-1 micrometer. When the average particle diameter is less than 0.01 μm, the particles are likely to aggregate and dispersibility may be insufficient. On the other hand, when the average particle diameter exceeds 3 μm, the surface roughness of the film becomes too rough and There may be a problem when a release layer is applied in the process.

  Furthermore, the particle content in the polyester layer is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the particle content is less than 0.001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film is insufficient. There is.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage for producing the polyester constituting each layer, but the polycondensation reaction may proceed preferably after the esterification stage or after the transesterification reaction.

  Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

  In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film in the present invention as necessary.

  The thickness of the polyester film constituting the first release film and the second release film of the present invention is not particularly limited as long as it can be formed as a film, but is usually 25 to 250 μm, preferably It is in the range of 38 to 188 μm, more preferably 50 to 125 μm.

  Next, although the manufacture example of the polyester film in this invention is demonstrated concretely, it is not limited to the following manufacture examples at all.

  First, a method of using the polyester raw material described above and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is necessary to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, the extending | stretching temperature orthogonal to the extending | stretching direction of the 1st step is 70-170 degreeC normally, and a draw ratio is 3.0 to 7 times normally, Preferably it is 3.5 to 6 times. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  The simultaneous biaxial stretching method can also be adopted for the production of the polyester film in the present invention. The simultaneous biaxial stretching method is a method in which the unstretched sheet is usually stretched and oriented in the machine direction and the width direction at 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is as follows: The area magnification is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be employed.

  Furthermore, a so-called coating stretching method (in-line coating) in which the film surface is treated during the above-described polyester film stretching step can be applied. When a coating layer is provided on a polyester film by a coating stretching method, coating can be performed simultaneously with stretching and the thickness of the coating layer can be reduced according to the stretching ratio, producing a film suitable as a polyester film. it can.

  The coating layer constituting both release films in the present invention contains a conductive compound (A) in order to improve antistatic properties and oligomer precipitation preventing properties. Such a compound (A) is preferably a polymer obtained by singly or copolymerizing thiophene or a thiophene derivative, and in particular, a compound comprising a thiophene or thiophene derivative doped with another anionic compound or a compound Those having an anionic group therein and being self-doped are preferred because they exhibit excellent conductivity. Examples of the compound (A) include those obtained by polymerizing a compound of the following formula (1) or (2) in the presence of a polyanion.

In the above formula, R ¹ and R ² each independently represent hydrogen or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, a hydroxyl group, or the like.

  In said formula, n represents the integer of 1-4.

  Examples of the polyanion used at the time of polymerization include poly (meth) acrylic acid, polymaleic acid, polystyrene sulfonic acid and the like. These acids may be partially or completely neutralized.

  As a method for producing such a polymer, for example, a method as disclosed in JP-A-7-90060 can be employed.

  In the present invention, a particularly preferable embodiment is one in which n = 2 in the compound of the above formula (2) and polystyrene sulfonic acid is used as a polyanion.

  Examples of the polyanion used at the time of polymerization include poly (meth) acrylic acid, polymaleic acid, polystyrene sulfonic acid and the like. These acids may be partially or completely neutralized.

  As a method for producing such a polymer, for example, a method as disclosed in JP-A-7-90060 can be employed.

  The binder polymer (B) constituting the coating layer in the present invention is a gel permeation chromatography (GPC) measurement according to a polymer compound safety evaluation flow scheme (sponsored by the Chemical Substance Council in November 1985). It is defined as a polymer compound having a number average molecular weight (Mn) of 1000 or more and having a film-forming property.

  The binder polymer (B) constituting the coating layer in the present invention may be either a thermosetting resin or a thermoplastic resin as long as it is compatible or mixed with the conductive compound. For example, polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyimides such as polyimide and polyamideimide; polyamides such as polyamide 6, polyamide 6,6, polyamide 12, and polyamide 11; polyvinylidene fluoride, polyvinyl fluoride, poly Fluorine resin such as tetrafluoroethylene, ethylenetetrafluoroethylene copolymer, polychlorotrifluoroethylene; vinyl resin such as polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl acetate, polyvinyl chloride; epoxy resin; oxetane resin; xylene resin; Aramid resin; Polyimide silicone; Polyurethane; Polyurea; Melamine resin; Phenol resin; Polyether; It includes copolymers of.

  These binder polymers (B) may be dissolved in an organic solvent, or may be made into an aqueous solution by adding a functional group such as a sulfo group or a carboxy group. Moreover, you may use together hardening | curing agents, such as a crosslinking agent and a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, etc. to a binder polymer (B) as needed.

  Among the binder polymers (B), at least one selected from polyester resins, acrylic resins, and polyurethane resins is preferable because mixing at the time of preparing the coating liquid is easy.

  The polyester resin used in the present invention is defined as a linear polyester having a dicarboxylic acid component and a glycol component as constituent components. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, phenylindanedicarboxylic acid, A dimer acid etc. can be illustrated. Two or more of these components can be used. Further, together with these components, a small proportion of unsaturated polybasic acids such as maleic acid, fumaric acid, itaconic acid and the like, and hydroxycarboxylic acids such as p-hydroxybenzoic acid and p- (β-hydroxyethoxy) benzoic acid. Can be used. The proportion of the unsaturated polybasic acid component or the hydroxycarboxylic acid component is at most 10 mol%, preferably 5 mol% or less.

As glycol components, ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, dimethylolpropionic acid Glycerin, trimethylolpropane, poly (ethyleneoxy) glycol, poly (tetramethyleneoxy) glycol, an alkylene oxide adduct of bisphenol A, an alkylene oxide adduct of hydrogenated bisphenol A, and the like. Two or more of these can be used.

Among these polyol components, ethylene glycol, bisphenol A ethylene oxide adduct, propylene oxide adduct, and 1,4-butanediol are preferable, and ethylene glycol and bisphenol A ethylene oxide adduct and propylene oxide adduct are more preferable. The polyester resin can be copolymerized with a small amount of a compound having a sulfonate group or a compound having a carboxylic acid group in order to facilitate aqueous liquefaction, which is preferable. Examples of the compound having a sulfonate group include 5-sodium sulfoisophthalic acid, 5-ammonium sulfoisophthalic acid, 4-sodium sulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid, 2-sodium sulfoisophthalic acid, and 5-potassium. Preferred examples include sulfonic acid alkali metal salt compounds or sulfonic acid amine salt compounds such as sulfoisophthalic acid, 4-potassium sulfoisophthalic acid, 2-potassium sulfoisophthalic acid, and sodium sulfosuccinic acid.

Examples of the compound having a carboxylate group include trimellitic anhydride, trimellitic acid, pyromellitic anhydride, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, dimethylolpropionic acid, and monoalkali metal salts thereof. Etc. The free carboxyl group is converted into a carboxylate group by allowing an alkali metal compound or an amine compound to act after copolymerization. A polyester obtained by selecting one or more compounds from these compounds and synthesizing them by a conventional polycondensation reaction can be used.

  Regarding the polyester resin, the glass transition temperature (hereinafter sometimes abbreviated as Tg) is preferably 40 ° C. or higher, more preferably 60 ° C. or higher. When Tg is less than 40 ° C., for the purpose of improving adhesiveness, when the coating thickness of the coating layer is increased, problems such as easy blocking may occur.

  The acrylic resin is a polymer made of a polymerizable monomer having a carbon-carbon double bond, as typified by acrylic and methacrylic monomers. These may be either a homopolymer or a copolymer. Moreover, the copolymer of these polymers and other polymers (for example, polyester, polyurethane, etc.) is also included. For example, a block copolymer or a graft copolymer. Furthermore, a polymer (possibly a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyester solution or a polyester dispersion is also included. Similarly, a polymer (in some cases, a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyurethane solution or polyurethane dispersion is also included. Similarly, a polymer obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in another polymer solution or dispersion (in some cases, a polymer mixture) is also included.

  The polymerizable monomer having a carbon-carbon double bond is not particularly limited, but representative compounds such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. Various carboxyl group-containing monomers and salts thereof; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydroxyfumarate, monobutylhydroxy Various hydroxyl-containing monomers such as itaconate; various (meth) acrylic such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate Acid esters; (Meth) ac Ruamido, various nitrogen-containing vinyl monomers such as diacetone acrylamide, N- methylol acrylamide or (meth) acrylonitrile. Further, in combination with these, polymerizable monomers as shown below can be copolymerized. Namely, various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene and vinyltoluene, various vinyl esters such as vinyl acetate and vinyl propionate; γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, Various silicon-containing polymerizable monomers such as methacryloyl silicon macromer; phosphorus-containing vinyl monomers; vinyl chloride, biliden chloride, vinyl fluoride, vinylidene fluoride, trifluorochloroethylene, tetrafluoroethylene, chlorotrifluoroethylene And various vinyl halides such as hexafluoropropylene; and various conjugated dienes such as butadiene.

  In the acrylic resin, the glass transition temperature (hereinafter sometimes abbreviated as Tg) is preferably 40 ° C. or higher, more preferably 60 ° C. or higher. When Tg is less than 40 ° C., for the purpose of improving adhesiveness, when the coating thickness of the coating layer is increased, problems such as easy blocking may occur.

  The polyurethane resin in the present invention refers to a polymer compound having a urethane bond in the molecule. Among these, when considering suitability for in-line coating, a water-dispersible or water-soluble urethane resin is preferable. In order to impart water dispersibility or water solubility, it is possible to introduce a hydrophilic group such as a hydroxyl group, a carboxyl group, a sulfonic acid group, a sulfonyl group, a phosphoric acid group, or an ether group into the urethane resin. Among the hydrophilic groups, a carboxylic acid group or a sulfonic acid group is preferably used from the viewpoint of improving physical properties of the coating film and adhesion.

  As a specific production example of the urethane resin, for example, a method utilizing a reaction between a hydroxyl group and an isocyanate can be mentioned. As the hydroxyl group used as the raw material, polyol is preferably used, and examples thereof include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

  Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like.

  Polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides. Product and polyhydric alcohol (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol 2-methyl-2-propyl-1 3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexane Diol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyl dialkanolamine, lactone diol, etc.).

  Examples of polycarbonate polyols include polycarbonate diols obtained by dealcoholization reaction from polyhydric alcohols and dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, and the like, such as poly (1,6-hexylene) carbonate, poly ( And 3-methyl-1,5-pentylene) carbonate.

  Examples of the polyisocyanate compound used for obtaining the urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α ′, α ′. -Aliphatic diisocyanates having aromatic rings such as tetramethylxylylene diisocyanate, aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Methanzi Cyanate, alicyclic diisocyanates such as isopropylidene dicyclohexyl diisocyanates. These may be used alone or in combination.

  When synthesizing a urethane resin, a conventionally known chain extender may be used, and the chain extender is not particularly limited as long as it has two or more active groups that react with an isocyanate group. A chain extender having two hydroxyl groups or amino groups is generally used.

  Examples of the chain extender having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol and butanediol, aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, and esters such as neopentyl glycol hydroxypivalate. It can be mentioned that glycols such as glycol are exemplified. Examples of the chain extender having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine, ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3- Propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- Aliphatic diamines such as decane diamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isoprobilitincyclohexyl-4,4′-diamine, 1,4-diaminocyclohexane, 1 , 3-Bisaminomethylcyclohexa And alicyclic diamines such as

  The blending ratio of the polyurethane resin in the coating layer is in the range of 10 to 80%, more preferably in the range of 20 to 60%. When the said range is less than 10%, the adhesiveness with respect to a mold release layer may fall. On the other hand, when it exceeds 80%, the adhesion performance becomes saturated, and even if the amount is increased further, a remarkable effect may not be obtained.

  In the present invention, the coating layer constituting the release film preferably contains a polyurethane resin for the purpose of improving the adhesion to the release layer.

  The coating liquid for providing the coating layer in the present invention is selected from the group of glycerin (C1), polyglycerin (C2), glycerin or an alkylene oxide adduct (C3) to polyglycerin as the component (C). It is preferred to contain more than one compound or derivative thereof.

  Glycerin and polyglycerin are compounds represented by the following general formula (3).

  In the above formula, the compound with n = 1 is glycerol, and the compound with n of 2 or more is polyglycerol. In the present invention, n in the above formula is preferably in the range of 1-20, more preferably in the range of 2-20. When glycerin is used, the transparency of the resulting coating layer may be slightly inferior.

  Further, the alkylene oxide adduct to glycerin or polyglycerin has a structure in which alkylene oxide or a derivative thereof is added and polymerized to the hydroxyl group of glycerin or polyglycerin represented by the general formula (3).

  Here, the structure of the alkylene oxide added or its derivative may differ for every hydroxyl group of glycerol or polyglycerol skeleton. Moreover, it is sufficient that it is added to at least one hydroxyl group in the molecule, and it is not necessary that alkylene oxide or a derivative thereof is added to all hydroxyl groups.

  A preferable alkylene oxide or derivative thereof has a structure including an ethylene oxide or propylene oxide skeleton. If the alkyl chain in the alkylene oxide structure becomes too long, the hydrophobicity becomes strong, the uniform dispersibility in the coating solution deteriorates, and the antistatic property and transparency of the coating film tend to deteriorate. Particularly preferred is ethylene oxide.

  In such an alkylene oxide adduct to glycerin or polyglycerin, the copolymerization ratio of alkylene oxide or its derivative to glycerin or polyglycerin skeleton is not particularly limited, but when the glycerin or polyglycerin moiety is 1 in terms of molecular weight ratio The alkylene oxide moiety is preferably 20 or less, more preferably 10 or less. When the ratio of the alkylene oxide or its derivative to the glycerin or polyglycerin skeleton is larger than this range, the characteristics of the ordinary polyalkylene oxide are close to those obtained, and the effects of the present invention may not be sufficiently obtained. is there.

  With regard to the compound (C) in the present invention, particularly preferred embodiments include polyglycerol (C2) and alkylene oxide adduct (C3) to glycerol or polyglycerol. As the polyglycerin (C2), those having n of 2 to 20 in the compound of the above formula (3) are particularly preferred. Further, as the alkylene oxide adduct (C3) to glycerin or polyglycerin, a compound having a structure in which ethylene oxide or polyethylene oxide is added to n = 2 in the compound of the above formula (3) is preferable. The number is particularly preferably in the range of 300 to 2000 in terms of weight average molecular weight as the final compound (C3).

In the present invention, regarding the coating layer constituting the second release film, the weight of the coating agent component (A) in the coating layer is preferably 0.5 mg / m ² or more, more preferably 1 mg / m ² or more. Is good. When the amount of the coating agent component compound (A) is less than 0.5 mg / m 2, the antistatic property tends to be insufficient.

  In the present invention, the ratio of the coating agent component (A) in the coating layer constituting the release film is not limited, but the upper limit is preferably 90%, more preferably 80%, and most preferably 60%. It is. When the ratio of the coating agent component (A) exceeds 90% by weight, the transparency of the coating film may be insufficient, or the antistatic performance may be insufficient. On the other hand, the lower limit is preferably 1%, more preferably 2%. When the weight ratio of the coating agent component (A) is less than 1%, the antistatic performance may be insufficient.

  In the coating layer constituting the release film in the present invention, the ratio of the coating agent component (A) and the coating agent component (B) is preferably in the range of 90/10 to 1/99 by weight. More preferably, it is in the range of 70/30 to 1/99, and most preferably in the range of 50/50 to 2/98. Outside this range, the antistatic performance or the appearance of the coating film tends to deteriorate.

  In the coating solution used in the present invention, a surfactant can be contained in order to improve the coating property to the polyester film. As this surfactant, it is more preferable to use a surfactant containing (poly) alkylene oxide, (poly) glycerin, or a derivative thereof in the structure, since it does not inhibit the antistatic property of the resulting coating layer.

  The coating liquid used in the present invention includes an antifoaming agent, a coating property improver, a thickener, an organic lubricant, a release agent, organic particles, inorganic particles, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, You may contain additives, such as a pigment. These additives may be used alone or in combination of two or more as necessary. Moreover, as these additives, it is more preferable to use those containing (poly) alkylene oxide, (poly) glycerin, or derivatives thereof in the structure without inhibiting the antistatic property of the resulting coating layer.

  The coating liquid in the present invention is preferably an aqueous solution or a water dispersion from the viewpoint of handling, working environment, and stability of the coating liquid composition, but water is the main medium. An organic solvent may be contained as long as it does not exceed the range.

  The coating layer in the present invention is provided by coating a coating solution containing a specific compound on a film, and in the present invention, it is particularly preferably provided by in-line coating in which coating is performed during film formation.

  The release layer constituting the first release film and the second release film in the present invention refers to a layer having releasability, and specifically, the peel force between the acrylic adhesive tape and the release layer. The present invention can be completed by setting (F) within a certain range.

  3-50 mN / cm is preferable and, as for the peeling force with respect to the adhesive layer 11 of the 1st release film 31, it is 5-25 mN / cm more preferably. When the peeling force of the first release film is less than 3 mN / cm, the release film may be easily peeled off in a scene that does not need to be peeled off. Moreover, when the peeling force of the first release film exceeds 50 mN / cm, a peeling phenomenon called “floating” occurs between the second release film and the adhesive layer in the step of peeling the first release film. There is.

  By keeping the absolute value of the peeling force of the first release film 31 low, even if the absolute value of the peeling force of the second release film 32 is lowered, the difference in the peeling force between the release films 31 and 32 is increased. It becomes possible. Moreover, the 1st release film 31 peels easily from the adhesive layer 11 in the scene which does not need to peel originally before use by making the peeling force of the 1st release film 31 or more into a fixed value or more. Alternatively, it is possible to prevent the first release film 31 from floating from the adhesive layer 11.

  On the other hand, the peeling force of the second release film 32 is preferably 20 to 100 mN / cm, and more preferably 30 to 80 mN / cm. If the peeling force of the second release film is less than 20 mN / cm, when the first release film is peeled off, there may be a problem that a part of the second release film peels off. Moreover, when the peeling force of a 2nd mold release film exceeds 100 mN / cm, malfunctions, such as the component derived from an adhesive layer remaining in a 2nd mold release film, may arise.

  It is preferable that the base-material-less double-sided pressure-sensitive adhesive sheet of the present invention provides a difference in peel force between the first release film and the second release film in addition to the above-described peel force adjustment.

  The peeling force of the second release film 32 is usually 2.0 times or more, preferably 3.0 times or more that of the first release film 31. When the peeling force of the second release film 32 is less than 2.0 times the peeling force of the first release film 31, the second release film 32 adheres when the first release film 31 on the light release side is peeled off. In some cases, a phenomenon of floating from the agent layer 11 occurs, the adhesive layer component remains on the second release film 32, or a problem such as zipping occurs.

  The release layer constituting the first release film in the present invention can be provided on the polyester film by the above-described coating stretching method (inline coating). The coating stretching method (in-line coating) is not limited to the following, but for example, in sequential biaxial stretching, the first stage of stretching may be completed and the coating treatment may be performed before the second stage of stretching. it can. When a release layer is provided on a polyester film by a coating and stretching method, the film can be applied simultaneously with stretching, and the thickness of the release layer can be reduced according to the stretching ratio. Can be manufactured.

  Moreover, it is preferable that the release layer which comprises the release film in this invention contains a curable silicone resin in order to make mold release property favorable. It may be a type mainly composed of a curable silicone resin, or a modified silicone type by graft polymerization with an organic resin such as a urethane resin, an epoxy resin or an alkyd resin may be used as long as the gist of the present invention is not impaired. Also good.

  As the type of the curable silicone resin, any of the curing reaction types such as an addition type, a condensation type, an ultraviolet curable type, an electron beam curable type, and a solventless type can be used. Specific examples include KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-856, X-62-2422, X-62-2461, X manufactured by Shin-Etsu Chemical Co., Ltd. -62-1387, X-62-5039, X-62-5040, KNS-3051, X-62-1496, KNS320A, KNS316, X-62-1574A / B, X-62-7052, X-62-7028A / B, X-62-7619, X-62-7213, manufactured by Momentive Performance Materials YSR-3022, TPR-6700, TPR-6720, TPR-6721, TPR6500, TPR6501, UV9300, UV9425, XS56-A2775, XS56-A2982, UV9430, TPR6600, TPR66 4, TPR6605, SRX357, SRX211, SD7220, SD7292, LTC750A, LTC760A, LTC303E, SP7259, BY24-468C, SP7248S, BY24-452, DKQ3-202, DKQ3-203, manufactured by Toray Dow Corning Co., Ltd. , DKQ3-205, DKQ3-210, and the like. Further, a release control agent may be used in combination in order to adjust the release property of the release layer.

  In the present invention, the curing conditions for forming the release layer on the polyester film are not particularly limited, and when providing the release layer by off-line coating, usually at 120 to 200 ° C. for 3 to 40 seconds, The heat treatment is preferably performed at 100 to 180 ° C. for 3 to 40 seconds as a guide. Moreover, you may use together heat processing and active energy ray irradiation, such as ultraviolet irradiation, as needed. In addition, a conventionally well-known apparatus and energy source can be used as an energy source for hardening by active energy ray irradiation.

The coating amount (after drying) of the release layer is usually from 0.005 to 1 g / m ² , preferably from 0.005 to 0.5 g / m ² , more preferably from 0.01 to 5 in terms of coatability. The range is 0.2 g / m ² . When the coating amount (after drying) is less than 0.005 g / m ² , the coating property may be less stable and it may be difficult to obtain a uniform coating film. On the other hand, when the coating is thicker than 1 g / m ² , the coating layer adhesion and curability of the release layer itself may be lowered.

  As a structure of the base material-less double-sided pressure-sensitive adhesive sheet in the present invention, it is necessary to bond a release film on both sides of the pressure-sensitive adhesive layer. Regarding the thickness ratio of each release film, the handleability is taken into consideration, and the thickness of the second release film is preferably 2 times or more, preferably 3 times or more the thickness of the first release film. For example, by reducing the film thickness of the first release film, there is an advantage that it is possible to prevent floating that occurs at the interface between the second release film and the adhesive layer when the first release film is peeled off. In addition, when the adhesive layer is applied on the release surface of the second release film, in order to eliminate the influence of foreign matters and irregularities in the process, the influence of irregularities and foreign matters is taken into account when manufacturing costs are taken into consideration. It is preferable to further increase the film thickness of the second release film that is more easily received.

  In the present invention, conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating and the like can be used as a method for providing a release layer on the polyester film. Regarding the coating method, there is a description example in “Coating method” published by Yasuharu Harasaki in 1979.

  Regarding the first release film and the second release film in the present invention, an adhesive layer, an antistatic layer, an oligomer precipitation-preventing layer, etc., as long as the gist of the present invention is not impaired on the film surface on which no release layer is provided. A coating layer may be provided.

  Further, the polyester film constituting the first release film and the second release film may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

In the present invention, when producing a release film, after applying the coating layer on the polyester film, one end, after winding up the film, may further provide a release layer on the coating layer,
After applying and drying the coating layer on the polyester film, a release layer may be provided on the coating layer continuously, and any method may be used in the present invention.

In the first release film and the second release film constituting the substrate-less pressure-sensitive adhesive sheet in the present invention, the surface specific resistance (R) value of the release surface is preferably 1 × 10 ¹⁰ (Ω) or less. . The R value is more preferably 1 × 10 ⁹ (Ω), and most preferably 1 × 10 ⁸ (Ω) or less. When R exceeds 1 × 10 ¹⁰ (Ω), problems such as the inclusion of foreign matter when the release film is peeled off from the substrate-less pressure-sensitive adhesive sheet are caused.

Furthermore, in the 2nd mold release film in this invention, after heat processing (180 degreeC, 10 minutes), the oligomer amount (OL) extracted from the mold release layer surface needs to be 0.5 mg / m < ² > or less. When OL exceeds 0.5 mg / m ² , when the release surface of the release film is bonded to the pressure-sensitive adhesive layer, oligomers are precipitated over time, which causes trouble during inspection in the inspection process involving optical evaluation. It becomes like this.

  Next, the pressure-sensitive adhesive layer constituting the substrate-less double-sided pressure-sensitive adhesive sheet in the present invention will be described below. The pressure-sensitive adhesive layer in the present invention means a layer composed of an adhesive material, and conventionally known materials can be used as long as the gist of the present invention is not impaired. As one specific example, the case where an acrylic adhesive is used will be described below.

  In the present invention, the acrylic pressure-sensitive adhesive means a pressure-sensitive adhesive layer containing, as a base polymer, an acrylic polymer formed using an acrylic monomer as an essential monomer component. The acrylic polymer has (meth) acrylic acid alkyl ester and / or (meth) acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as an essential monomer component (more preferably as a main monomer component). ) It is preferably an acrylic polymer to be formed. Furthermore, the acrylic polymer is preferably an acrylic polymer formed using (meth) acrylic acid alkyl ester and acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as essential monomer components.

  The pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer formed using (meth) acrylic acid alkyl ester and acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as essential monomer components. preferable.

In addition, the monomer component forming the acrylic polymer that is the base polymer in the pressure-sensitive adhesive layer of the present invention further contains a polar group-containing monomer, a polyfunctional monomer, and other copolymerizable monomers. It may be contained as a polymerization monomer component. In addition, said "(meth) acryl" represents "acryl" and / or "methacryl", and others are the same. Although not particularly limited, the content of the acrylic polymer as the base polymer in the pressure-sensitive adhesive layer of the present invention is preferably 60% by weight or more based on the total weight (100% by weight) of the pressure-sensitive adhesive layer. Preferably it is 80 weight% or more.

  As a monomer component for forming the acrylic polymer, a (meth) acrylic acid alkyl ester having a linear or branched alkyl group (hereinafter sometimes simply referred to as “(meth) acrylic acid alkyl ester”) is used. It can be used suitably. Specific examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth ) Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate , Octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic acid Isodecyl, undecyl (meth) acrylate, dodecyl (meth) acrylate, (Meth) acrylic acid tridecyl, (meth) acrylic acid tetradecyl, (meth) acrylic acid pentadecyl, (meth) acrylic acid hexadecyl, (meth) acrylic acid heptadecyl, (meth) acrylic acid octadecyl, (meth) acrylic acid nonadecyl, (meta ) (Meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group such as eicosyl acrylate. Moreover, the (meth) acrylic acid alkyl ester may be used alone or in combination of two or more. Among them, (meth) acrylic acid alkyl ester having 2 to 14 carbon atoms in the alkyl group is preferable, and (meth) acrylic acid alkyl ester having 2 to 10 carbon atoms in the alkyl group is more preferable.

  Examples of the polar group-containing monomer include, for example, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and other carboxyl group-containing monomers or anhydrides thereof (such as maleic anhydride) Hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, Hydroxyl group-containing monomers such as vinyl alcohol and allyl alcohol; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N -Butoxymethyl (meth) acrylamide, N-hydroxy Amide group-containing monomers such as ethyl acrylamide; Amino group-containing monomers such as aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate; (meth) Glycidyl group-containing monomers such as glycidyl acrylate and methyl glycidyl (meth) acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl-2-pyrrolidone, (meth) acryloylmorpholine, Heterocycle-containing vinyl monomers such as N-vinyl pyridine, N-vinyl piperidone, N-vinyl pyrimidine, N-vinyl piperazine, N-vinyl pyrrole, N-vinyl imidazole, N-vinyl oxazole; sodium vinyl sulfonate, etc. Sulfonic acid group-containing monomer; 2-hydroxyethyla Phosphoric acid group-containing monomers such as Leroy Le phosphate; cyclohexyl maleimide, imide group-containing monomers such as isopropyl maleimide; 2-methacryloyloxy such acryloyloxyethyl isocyanate group-containing monomers such as isocyanate. The polar group-containing monomers can be used alone or in combination of two or more.

  Examples of the polyfunctional monomer include hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, Neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methanetri (meth) Examples include acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate. The said polyfunctional monomer can also be used individually or in combination of 2 or more types.

  The content of the polyfunctional monomer is preferably 0.5% by weight or less with respect to 100% by weight of the monomer component forming the acrylic polymer. When the content exceeds 0.5% by weight, for example, the cohesive force of the pressure-sensitive adhesive layer becomes too high, and the stress relaxation property may be lowered.

  Examples of copolymerizable monomers (other copolymerizable monomers) other than the polar group-containing monomer and multifunctional monomer include cyclopentyl (meth) acrylate and cyclohexyl (meth) acrylate. (Meth) acrylic acid ester having an alicyclic hydrocarbon group such as isobornyl (meth) acrylate, and (meth) acrylic acid ester having an aromatic hydrocarbon group such as phenyl (meth) acrylate. (Meth) acrylic acid esters other than alkyl acrylates, alkoxyalkyl (meth) acrylates, polar group-containing monomers and polyfunctional monomers; vinyl esters such as vinyl acetate and vinyl propionate; styrene, Aromatic vinyl compounds such as vinyltoluene; ethylene, butadiene, isoprene, isobutylene, etc. Fins or dienes; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

  The acrylic polymer can be prepared by polymerizing the above monomer components by a conventionally known or conventional polymerization method. Examples of the polymerization method of the acrylic polymer include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by active energy ray irradiation (active energy ray polymerization method). Among these, the solution polymerization method and the active energy ray polymerization method are preferable in terms of transparency, water resistance, production cost and the like.

  Examples of the active energy rays irradiated in the above active energy ray polymerization (photopolymerization) include ionizing radiation such as α rays, β rays, γ rays, neutron rays, electron rays, and ultraviolet rays, among others. Ultraviolet rays are suitable for the use of the present invention. Further, the irradiation energy, irradiation time, irradiation method, and the like of the active energy ray are not particularly limited as long as they do not impair the gist of the present invention.

  In the solution polymerization, various common solvents can be used. Specific examples include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic rings such as cyclohexane and methylcyclohexane Organic hydrocarbons such as formula hydrocarbons; ketones such as methyl ethyl ketone and methyl isobutyl ketone are exemplified. A solvent can be used individually or in combination of 2 or more types.

  In preparing the acrylic polymer, a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator (photoinitiator) can be used depending on the type of polymerization reaction. A polymerization initiator can also be used individually or in combination of 2 or more types.

  With respect to the photopolymerization initiator, it is not particularly limited, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, Photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, and the like can be used. The amount of the photopolymerization initiator used is not particularly limited as long as it does not impair the gist of the present invention. For example, the amount of the photopolymerization initiator is 0.1% relative to 100 parts by weight of the total amount of monomer components forming the acrylic polymer. A range of 01 to 0.2 parts by weight is preferred.

  Specific examples of the benzoin ether photopolymerization initiator include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one. And anisole methyl ether. Examples of the acetophenone photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl). Examples include dichloroacetophenone. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one. . Specific examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the benzyl photopolymerization initiator include benzyl. Specific examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like. Specific examples of the ketal photopolymerization initiator include benzyldimethyl ketal. Specific examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like.

  Specific examples of the thermal polymerization initiator include azo polymerization initiators [for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis. (2-methylpropionic acid) dimethyl, 4,4′-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [ 2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (N, N′-di) Methyleneisobutylamidine) dihydrochloride], peroxide-based polymerization initiators (eg, dibenzoyl peroxide, tert-butylpermaleate, etc.), redox Scan type polymerization initiators and the like. The amount of the thermal polymerization initiator used is not particularly limited as long as it does not impair the gist of the present invention.

  In the acrylic pressure-sensitive adhesive layer used as one form of the pressure-sensitive adhesive layer in the present invention, a cross-linking agent, a cross-linking accelerator, a tackifier (for example, rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble, if necessary) Phenol resins, etc.), anti-aging agents, fillers, colorants (pigments and dyes, etc.), UV absorbers, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, etc. An additive can be used in the range which does not impair the characteristic of this invention. Moreover, when forming an adhesive layer, various general solvents can also be used. The type of the solvent is not particularly limited, and those exemplified as the solvent used in the above solution polymerization can be used.

  The said crosslinking agent can control the gel fraction of an adhesive layer by bridge | crosslinking the base polymer of an adhesive layer. As crosslinking agents, isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents Agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, amine crosslinking agents, and the like, and isocyanate crosslinking agents and epoxy crosslinking agents can be preferably used. A crosslinking agent can also be used individually or in combination of 2 or more types.

Next, in the base material-less double-sided pressure-sensitive adhesive sheet of the present invention, when an acrylic pressure-sensitive adhesive composition is used at the time of forming a pressure-sensitive adhesive layer, which is a constituent unit, for example, an optical member (for example, a surface protective layer, a touch panel, and By replacing the air gap between the display surfaces of the image display unit) with a transparent adhesive sheet having a refractive index close to that of the optical member as compared with air, the light transmission is improved, and the brightness of the image display device In consideration of suppressing the decrease in contrast, the pressure-sensitive adhesive layer itself is preferably designed flexibly. For example, the storage elastic modulus (G ′) in dynamic viscoelasticity is preferably 1.0 × 10 ⁵ Pa or less, and more preferably 5.0 × 10 ⁴ Pa or less. When the storage elastic modulus (G ′) exceeds 1.0 × 10 ⁵ Pa, for example, when a gap existing between optical members is filled, the filled adhesive layer does not reach every corner and peels off at the end, Or there may be a problem such as floating.

  The thickness of the pressure-sensitive adhesive layer constituting the substrate-less double-sided pressure-sensitive adhesive sheet in the present invention is 25 μm to 200 μm, preferably 25 μm to 100 μm. In the case of less than 25 μm, for example, the gap generated between the optical members may be too large, and it may be difficult to fill every corner with the adhesive layer. On the other hand, when the thickness of the pressure-sensitive adhesive layer exceeds 200 μm, the pressure-sensitive adhesive layer thickness is excessively thicker than the gap generated between the optical members, and there is a problem such that the excess pressure-sensitive adhesive layer component protrudes between the optical members. May occur.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measuring method used in the present invention is as follows.

(1) Measurement of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Measurement of average particle diameter (d ₅₀ : μm) Integration (weight basis) 50% in equivalent spherical distribution measured using centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) Was the average particle size.

(3) Measurement of glass transition temperature (Tg) of polyester resin Using a DSC-II type measuring device manufactured by PerkinElmer, the sample was heated at a heating rate of 10 ° C./min under a nitrogen gas stream at a rate of 10 ° C./min. The segregation start temperature was defined as Tg.

(4) Measurement of release film peeling force (F1 and F2) After attaching one side of a double-sided adhesive tape (Nitto Denko “No. 502”) to the surface of the release layer of the sample film, the size is 50 mm × 300 mm Cut and measure the peel force after standing at room temperature for 1 hour. For the peeling force, a tensile tester (“Intesco model 2001 type” manufactured by Intesco Co., Ltd.) was used, and 180 ° peeling was performed under a tensile speed of 300 mm / min.

(5) Measurement of surface specific resistance (R) of release film The surface specific resistance on the surface of the release layer of the sample film was measured based on the method of (5-1) below. In the method (5-1), since the surface resistivity higher than 1 × 10 ⁸ Ω cannot be measured, the method (5-2) was used for the sample that could not be measured in (5-1).
"Measuring method"
(5-1) Low resistivity meter manufactured by Mitsubishi Chemical Co., Ltd .: Loresta GP MCP-T600 was used, and the surface resistivity was measured after conditioning the sample for 30 minutes in a measurement atmosphere of 23 ° C. and 50% RH.
(5-2) Using a high resistance measuring instrument made by Hewlett-Packard Japan: HP4339B and measuring electrode: HP16008B, the sample was conditioned for 30 minutes in a measurement atmosphere of 23 ° C. and 50% RH, and then the surface resistivity was measured. did.
<Criteria>
A: R (Ω) is 1 × 10 ⁸ or less (practical level, particularly good)
○: R (Ω) is 1 × 10 ⁹ or less (practical level)
Δ: R (Ω) is 1 × 10 ¹⁰ or less (a level that may cause a problem in practical use)
×: R (Ω) exceeds 1 × 10 ¹⁰ (practical level)

(6) Measurement of oligomer amount (OL) extracted from release layer surface of release film An unheat-treated release film is heated in air at 180 ° C. for 10 minutes in advance. After that, the heat-treated film is brought into close contact with the inner surface of a box having a top and width of 10 cm and a height of 3 cm, and the box shape is obtained. Next, 4 ml of DMF (dimethylformamide) is placed in the box prepared by the above method and left for 3 minutes, and then DMF is recovered. The recovered DMF was supplied to liquid chromatography (manufactured by Shimadzu Corporation: LC-7A) to determine the amount of oligomer in DMF, and this value was divided by the film area in contact with DMF to obtain the amount of film surface oligomer (mg / M ² ).

  The amount of oligomer in DMF was determined from the peak area ratio between the standard sample peak area and the measured sample peak area (absolute calibration curve method). The standard sample was prepared by accurately weighing the oligomer (cyclic trimer) collected in advance and dissolving it in DMF accurately measured. The concentration of the standard sample is preferably in the range of 0.001 to 0.01 mg / ml.

The conditions for the liquid chromatograph were as follows.
Mobile phase A: Acetonitrile Mobile phase B: 2% acetic acid aqueous solution Column: “MCI GEL ODS 1HU” manufactured by Mitsubishi Chemical Corporation
Column temperature: 40 ° C
Flow rate: 1 ml / min Detection wavelength: 254 nm

(7) Coating film adhesion promotion evaluation of release film (practical property substitution evaluation)
The sample film was left in a constant temperature and humidity chamber at 60 ° C. and 80% RH for 4 weeks, and then the sample film was taken out. Thereafter, the release surface of the sample film was rubbed with a tentacle five times, and the degree of release of the release layer was determined according to the following criteria.
<Criteria>
○: No dropout of the coating film (practical level)
Δ: The coating film turns white but does not fall off (practical level)
×: Detachment of the coating film was confirmed (practically difficult level)

(8) Storage elastic modulus (G ′) measurement of pressure-sensitive adhesive layer The separator was peeled off from the double-sided pressure-sensitive adhesive sheets obtained in the examples and comparative examples, and only the acrylic pressure-sensitive adhesive layer was laminated, and the thickness (after drying) ) A laminate of 1.5 mm ± 0.1 mm acrylic pressure-sensitive adhesive layer was prepared and used as a measurement sample. The above measurement sample was measured at a temperature rising rate of 5 ° C./min in the range of −70 to 200 ° C. under the condition of a frequency of 1 Hz using an “Advanced Rheometric Expansion System (ARES)” manufactured by Rheometric Scientific. The storage elastic modulus (G ′) at ° C. was determined. In addition, the storage elastic modulus (G ') of the adhesion layer used by the Example and comparative example in this invention was 5.0 * 10 < ⁴ > Pa.

(9) Appearance of application (practical property substitution evaluation)
A sample film with a width of 1000 mm is irradiated with light of halogen light on the surface of the release layer on which the coating layer is provided, about 10 m in the longitudinal direction, and the release layer is visually observed to appear uneven due to the coating layer. Appearance was judged according to criteria.
<Criteria>
○: A pattern that looks uneven is not confirmed and is good △: A pattern that appears uneven is slightly confirmed ×: A pattern that appears uneven is clearly confirmed and is not good In the above, it is long Although unevenness has been confirmed with respect to the sample, it is possible to determine whether the unevenness is good or not by a method similar to the above even for a film of about A4 size.

(10) Zipping occurrence status (practical property substitution evaluation)
The following pressure-sensitive adhesive composition was applied to the second release film, heat-treated at 100 ° C. for 5 minutes, and then a pressure-sensitive adhesive layer having a thickness (after drying) of 150 μm was obtained. Next, in the base material-less double-sided pressure-sensitive adhesive sheet in which the first release film is bonded to the surface of the pressure-sensitive adhesive layer, the peeling state is observed when the first release film is peeled off, and the occurrence of zipping is determined according to the following criteria. It was.
<Acrylic adhesive composition>
(Monomer composition)
2-ethylhexyl acrylate 70% by weight
2-methoxyethyl acrylate 29% by weight
4-hydroxybutyl acrylate 1% by weight
0.1 part of Nippon Polyurethane Coronate L was added to 100 parts by weight of the monomer composition to obtain an acrylic pressure-sensitive adhesive layer forming composition.
<Criteria>
○: Peeling very smoothly, no peeling streaks, no peeling noise △: Minor peeling streaks are observed, slight peeling noise is generated, or slight zipping occurs (problem is practically problematic) May have a level)
X: Peeling streaks are observed, peeling noise is generated, or zipping occurs (a level that causes a problem in practical use)

(11) Evaluation of peelability of first release film and second release film (practical property substitution evaluation)
In the item (10), when the first release film was peeled off, sensory evaluation was performed according to the following criteria for the situation of the interface between the second release layer and the pressure-sensitive adhesive layer.
<Criteria>
○: No abnormality is observed at the interface between the second release layer and the pressure-sensitive adhesive layer (practically problematic level)
Δ: Slight lifting is observed at the interface between the second release layer and the pressure-sensitive adhesive layer (a level that may cause a practical problem)
X: Clear floating is observed at the interface between the second release layer and the pressure-sensitive adhesive layer (practically problematic level)

(12) Comprehensive evaluation (practical property substitution evaluation)
Using the base material-less double-sided pressure-sensitive adhesive sheet produced in Examples and Comparative Examples, the evaluation criteria for zipping occurrence, peelability, antistatic properties, oligomer sealing properties, adhesion, and coating appearance are as follows. A comprehensive evaluation was conducted.
<Criteria>
○: All occurrences of zipping, peelability, antistatic property, oligomer sealing property, adhesion, and coating appearance are ○ (a level that causes no problem in practical use).
Δ: At least one of the zipping occurrence status, peelability, antistatic property, oligomer sealing property, adhesion, and coating appearance is Δ (a level that may cause a problem in practice).
×: At least one of zipping occurrence status, peelability, antistatic property, oligomer sealing property, adhesion, and appearance of coating is × (practically problematic level)

The polyester used in the examples and comparative examples was prepared as follows.
<Manufacture of polyester>
Production Example 1 (Polyethylene terephthalate A1)
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, the temperature is raised by heating, methanol is distilled off, transesterification is performed, and 4 hours are required from the start of the reaction. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, after adding 0.04 part of ethylene glycol slurry ethyl acid phosphate and 0.03 part of antimony trioxide, the temperature reached 280 ° C. and the pressure reached 15 mmHg in 100 minutes. It was 0.3 mmHg. After 4 hours, the system was returned to atmospheric pressure to obtain polyethylene terephthalate A1 having an intrinsic viscosity of 0.61.

Production Example 2 (Polyethylene terephthalate A2)
In Production Example 1, production was carried out in the same manner as in Production Example 1 except that 0.6 part of silica particles having an average particle diameter of 2.5 μm was added to obtain polyethylene terephthalate A2 having an intrinsic viscosity of 0.62.

Production Example 3 (Production of polyester film F1)
A raw material blended with polyethylene terephthalate A1 and A2 at a ratio of 80% and 20%, respectively, is used as a raw material for the surface layer, and a raw material of polyethylene terephthalate A1 = 100% is supplied as a raw material for the intermediate layer to two vented extruders. After feeding to an extruder with melt and extruding at 290 ° C., an amorphous film having a thickness of about 1300 μm was obtained by cooling and solidifying on a cooling roll having a surface temperature set to 40 ° C. using an electrostatic application adhesion method. . This film was stretched 3.5 times in the longitudinal direction at 85 ° C., and a coating layer composed of the following coating composition was applied so that the coating thickness (after drying) was 0.03 g / m 2, and then at 100 ° C. The polyester film F1 stretched 3.8 times in the horizontal direction and heat-treated at 210 ° C. was provided with a coating layer having a thickness of 100 μm (thickness ratio = 2.5 μm / 95 μm / 2.5 μm).

<< Coating composition >>
(A): Baytron PAG manufactured by Starck Co., Ltd., consisting of polyethylene dioxythiophene and polystyrene sulfonic acid
(B1): Polyurethane resin A polyester polyol comprising 664 parts of terephthalic acid, 631 parts of isophthalic acid, 472 parts of 1,4-butanediol, and 447 parts of neopentyl glycol was obtained. Next, 321 parts of adipic acid and 268 parts of dimethylolpropionic acid were added to the obtained polyester polyol to obtain a pendant carboxyl group-containing polyester polyol A. Further, 160 parts of hexamethylene diisocyanate was added to 1880 parts of the polyester polyol A to obtain an aqueous polyurethane resin coating.
(B2): Polyester resin Tg = 63 ° C.
Acid component: terephthalic acid 50 mol%
Isophthalic acid 48mol%
5-Na sulfoisophthalic acid 2 mol%
Diol component: Ethylene glycol 50 mol%
Neopentyl glycol 50 mol%
(B3): Acrylic resin (manufactured by Nippon Carbide Corporation: RX-7023ED)
(C1): Glycerin in which n = 1 in the formula (3) (C2): Polyglycerin in which n = 2 in the formula (3) (C3): Polyglycerin in which n = 10 in the formula (3) (C4): Polyethylene oxide adduct to the polyglycerol skeleton in which n = 2 in the formula (3). Average molecular weight 350
(C5): Polyethylene oxide adduct to the polyglycerol skeleton in which n = 2 in the formula (3). Average molecular weight 2000
(C6): Polypropylene oxide adduct to the polyglycerol skeleton in which n = 2 in the formula (3). Average molecular weight 750
A / B1 / C1 = 40/40/20 (% by weight)

Production Example 4 (Production of Polyester Film F2) to Production Example 16 (Production of Polyester Film F14)
In Production Example 3, production was carried out in the same manner as in Production Example 3 except that the coating layer composition was changed as described in Table 1, and each polyester film was obtained.

Production Example 17 (Production of polyester film F15)
Manufactured in the same manner as in Manufacture Example 3 except that the film thickness constitution was different from (Thickness constitution ratio = 2.5 μm / 70 μm / 2.5 μm) in Production Example 3 to obtain a polyester film F15.

Production Example 18 (Production of polyester film F16)
Manufactured in the same manner as in Manufacture Example 3 except that the film thickness constitution was different from (Thickness constitution ratio = 2.5 μm / 45 μm / 2.5 μm) in Production Example 3, and a polyester film F16 was obtained.

Production Example 19 (Production of polyester film F17)
In Production Example 17, production was carried out in the same manner as in Production Example 17 except that no coating layer was provided, to obtain a polyester film F17.

Release layer composition-A
Curing type silicone resin (LTC303E: manufactured by Toray Dow Corning) 100 parts Curing agent (SRX212: manufactured by Toray Dow Corning) 1 part MEK / toluene mixed solvent (mixing ratio is 1: 1) 1500 parts

Release layer composition-B
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical) 100 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical) 1 part MEK / toluene mixed solvent (mixing ratio is 1: 1) 1500 parts

Release layer composition-C
Curing type silicone resin (KS-847H: manufactured by Shin-Etsu Chemical Co., Ltd.) 95 parts Heavy release control agent (BY24-4980: manufactured by Toray Dow Corning) 5 parts Curing agent (PL-50T: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part MEK / toluene mixed solvent (Mixing ratio is 1: 1) 1500 parts

Example 1:
<Manufacture of first release film>
After applying the release layer composition-A shown below on the coating layer of the polyester film F15 having a thickness of 50 μm offline by the reverse gravure coating method so that the coating amount (after drying) is 0.1 g / m ^2. And heat treatment at 120 ° C. for 30 seconds.

Release layer composition-A
Curing type silicone resin (LTC303E: manufactured by Toray Dow Corning) 100 parts Curing agent (SRX212: manufactured by Toray Dow Corning) 1 part MEK / toluene mixed solvent (mixing ratio is 1: 1) 1500 parts

  From the above, the characteristics of the obtained first release film are shown in Tables 2-3.

<Manufacture of second release film>
In the polyester film F1 having a thickness of 100 μm, after applying the release layer composition -C on the coating layer offline by a reverse gravure coating method so that the coating amount becomes 0.1 g / m ² (after drying), Heat treatment was performed at 120 ° C. for 30 seconds. The characteristics of the obtained second release film are shown in Tables 2-3.

<Manufacture of substrate-less double-sided PSA sheet>
On the release layer of the obtained second release film, after coating a coating liquid composed of the following acrylic pressure-sensitive adhesive composition, using a hot air circulating furnace, heat treatment at 100 ° C. for 5 minutes, An adhesive layer having a coating amount (after drying) of 50 μm was obtained.

<Acrylic pressure-sensitive adhesive layer forming composition>
(Monomer composition)
2-ethylhexyl acrylate 70% by weight
2-methoxyethyl acrylate 29% by weight
4-hydroxybutyl acrylate 1% by weight
0.1 part of Nippon Polyurethane Coronate L was added to 100 parts by weight of the monomer composition to obtain an acrylic pressure-sensitive adhesive layer forming composition. Next, the release layer of the first release film and the pressure-sensitive adhesive layer were bonded together to obtain a substrate-less double-sided pressure-sensitive adhesive sheet.

Example 2 , Reference Examples 3-4, Examples 5-9, Reference Example 10, Examples 11-15, and Comparative Examples 1-4:
In Example 1, except that the coating agent composition, the release layer composition, and the polyester film substrate thickness were changed as shown in Tables 1 and 2 below, the production was performed in the same manner as in Example 1, and the first release film 2 A release film was obtained. Then, it bonded together through the adhesive layer using both, and obtained the base material-less double-sided adhesive sheet. Tables 2 to 3 show the properties of the release films obtained in the above Examples , Reference Examples and Comparative Examples.

  The substrate-less double-sided pressure-sensitive adhesive sheet of the present invention has an antistatic property, a release property, an oligomer sealing property, and a good coating appearance. For example, various materials such as a liquid crystal polarizing plate manufacturing member and a capacitive touch panel manufacturing member. As an optical member, it can be suitably used.

10 Substrate-less double-sided adhesive sheet 11 Adhesive layer 31 First release film (light release sheet)
13 Release Film Base 14 Coating Layer 15 First Release Layer 32 Second Release Film (Heavy Release Sheet)
23 release film substrate 24 second release layer

Claims (1)

It is a substrate-less double-sided pressure-sensitive adhesive sheet in which release films with different peeling forces are laminated on both sides of the pressure-sensitive adhesive layer, and both release films are released onto the coating layer of the polyester film having a coating layer. The coating layer has the following (A) to (C), the following (A) is 1% by weight to 40% by weight and the following (B) with respect to all nonvolatile components in the coating solution. 40% by weight or more, and the following (C) is contained in the range of more than 0% by weight and 20 % by weight or less.
Conductive compound (A): a polymer made of thiophene or a thiophene derivative doped with another anion compound, or a compound made of thiophene or a thiophene derivative and having an anionic group and a self-doped polymer -Binder polymer (B): Polyurethane resin whose polyol component is a polyester polyol-Component (C): glycerin (C1), polyglycerin (C2), glycerin or selected from the group of alkylene oxide adducts (C3) to polyglycerin One or more compounds or derivatives thereof