JP2007199630A - Pressure-sensitive adhesive tape for forming braille and its using method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive tape for forming braille capable of foaming an arbitrary part of the pressure-sensitive adhesive tape and easily shaping and displaying braille without largely changing an adhesive strength on necessary processes before and after sticking to a body to be adhered. <P>SOLUTION: The pressure-sensitive adhesive tape for forming braille is provided with a pressure-sensitive adhesive layer formed on a half surface of a substrate, wherein thermally expanded fine particles are included in the pressure-sensitive adhesive layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adhesive tape for braille formation. More specifically, the present invention relates to a braille forming pressure-sensitive adhesive tape capable of thermally expanding or foaming a pressure-sensitive adhesive layer. Moreover, this invention relates to the usage method of the said adhesive tape for braille formation. More specifically, the present invention relates to a method of using a braille forming pressure-sensitive adhesive tape that is heated and expanded or foamed before and after being attached to an adherend.

  The Braille-forming adhesive tape of the present invention is particularly useful for Braille labels, Braille sheets, Braille tapes, and the like.

  Conventionally, techniques for forming braille with a print medium have been proposed. For example, there is a technique for forming braille by foaming an expandable ink containing a foaming agent and a resin binder at the time of printing or after printing (for example, see Patent Document 1).

  However, in the case of printed materials produced by these technologies, there are problems such as that some or all of the Braille prints may be removed or chipped by many people touching them or touching them many times. . In addition, when Braille is printed on the outer layer of the product, the Braille protrusions (convex parts) are partly or completely removed or missing due to vibration during transportation. As a result, the display contents and the like are changed, and in some cases, an accident or the like may occur.

  For this reason, there is a need for a Braille label or the like that can easily form and display Braille without part of the Braille display being peeled off or missing.

Japanese Patent Laid-Open No. 10-181183

  Therefore, an object of the present invention is to eliminate any problems in the conventional Braille labels, and to remove any part of the adhesive tape without greatly changing the adhesive force at a necessary stage before and after being attached to the adherend. An object of the present invention is to provide a pressure-sensitive adhesive tape for forming braille which can be foamed and easily formed and displayed.

  Another object of the present invention is to provide an arbitrary part of the adhesive tape for braille formation without greatly changing the adhesive force at a necessary stage before and after attaching the adhesive tape for braille formation having the above characteristics to the adherend. It is providing the usage method of the adhesive tape for braille formation which foams.

  In order to achieve the above-mentioned object, the present inventors have intensively studied the structure of the adhesive tape for braille formation, and as a result, made a sheet-like integrated type so that a part of the braille display is not lost, By using a Braille-forming adhesive tape with a structure, it is possible to easily form braille by foaming any part of the adhesive tape without greatly changing the adhesive strength at the necessary stage before and after application to the adherend. -It discovered that the adhesive tape for braille formation which can be displayed was obtained, and came to complete this invention.

  That is, the Braille-forming pressure-sensitive adhesive tape of the present invention is a Braille-forming pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer formed on one side of a base material layer, and contains thermally expandable microspheres in the pressure-sensitive adhesive layer. It is characterized by.

  The thermally expandable microsphere in the present invention refers to a microsphere in which a substance that expands by gasification by heating is encapsulated in an elastic shell, and includes what is called a thermally expandable microcapsule.

  According to the present invention, as shown in the results of Examples, a Braille-forming pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer formed on one side of the above-described base material layer and containing thermally expandable microspheres in the pressure-sensitive adhesive layer. By using it, it is possible to easily form and display braille by foaming any part of the adhesive tape for braille formation at the required stage before and after application to the adherend without greatly changing the adhesive strength. It will be something.

  Although the details of the reason why the adhesive tape for braille forming exhibits such characteristics are not clear, it is presumed as follows. First, by using a sheet-like integrated type, it is possible to prevent a portion of the braille display from being peeled off or missing. In addition, by using a pressure-sensitive adhesive layer containing thermally expandable microspheres before thermal expansion, it is easily heated and foamed at an arbitrary time (stage) and at an arbitrary location (part) on the tape. Things will be possible. In addition, since the outer layer becomes the base material layer, stickiness of the pressure-sensitive adhesive layer does not occur on the tape surface. Furthermore, the base material layer can be provided with an adhesive layer on the entire surface of one side of the protective sheet, and is firmly attached to the adherend due to the adhesive force of the adhesive layer. In addition, although the adhesive force of the foamed part may fall a little, in order to make it foam partially, it is hard to occur that a base material layer peels off. Moreover, since the base material layer covers the foamed portion, there is little deformation with respect to external force, and braille display can be maintained. Furthermore, the pressure-sensitive adhesive layer containing the thermally expandable microspheres makes it possible to easily attach the braille-formed foamed label and the braille-formed foamed adhesive tape to a place to be displayed. Moreover, since the heat-expandable microspheres are contained in the pressure-sensitive adhesive layer, the thickness of the entire pressure-sensitive adhesive tape may be reduced compared to the case where the base material layer contains heat-expandable microspheres.

  In addition, in this invention, a tape means a planar material and usually includes what is called a sheet | seat, a film, etc.

  In the above Braille-forming pressure-sensitive adhesive tape, it is preferable that the base material layer is made of a film that can be deformed following the spot-like foaming of the pressure-sensitive adhesive layer.

  In the Braille-forming pressure-sensitive adhesive tape, it is preferable that the base material layer is made of a film that can be thermally deformed when the thermally expandable microspheres are heated and foamed.

  In the above-mentioned Braille-forming pressure-sensitive adhesive tape, it is preferable that 1 to 300 parts by weight of the thermally expandable microspheres are contained with respect to 100 parts by weight of the base polymer constituting the base material layer.

  Furthermore, in the above-mentioned Braille-forming pressure-sensitive adhesive tape, it is preferable that the thickness of the pressure-sensitive adhesive layer can be 1.1 to 40 times that before the heat treatment by performing the heat treatment. By using such an adhesive tape for braille formation, it becomes easier to form braille.

  Moreover, the Braille label of the present invention is obtained by partially foaming the adhesive layer of the Braille-forming pressure-sensitive adhesive tape described above. By using such a braille label, it is possible to easily form braille and not to lose a part of the braille display.

  In the present invention, the Braille label (braille-formed foam label) refers to labels having a concavo-convex structure that is one of the touch-reading characters read by a visually impaired person using a fingertip, such as a Braille sheet, Braille tape, etc. Is included.

  On the other hand, the method of using the adhesive tape for braille formation of the present invention includes the step of affixing the adhesive tape for braille formation to an adherend, and then heat-treating the braille-forming portion of the adhesive tape for braille formation. Forming a step. In such a method of use, braille can be formed by foaming any part of the pressure-sensitive adhesive tape at a necessary stage without greatly changing the adhesive strength during use after being attached to the adherend.

  Furthermore, the method of using the adhesive tape for braille formation of the present invention includes a step of heat-treating a braille forming portion of the adhesive tape for braille formation to form braille, and then the adhesive tape for braille formation to an adherend. A step of attaching. In such a method of use, in use after being attached to the adherend after the heat treatment, braille is formed by foaming any part of the adhesive tape at a necessary stage without greatly changing the adhesive force before the heat treatment. Can be formed.

  Moreover, it is preferable that the process of the said heat processing is performed at 100-500 degreeC. By using it in such a heat treatment step, in the step of forming the pressure-sensitive adhesive layer, the risk of expansion and foaming in each step of the thermally expandable microspheres can be reduced, and the range of selection of materials and process temperature can be expanded. it can.

  Hereinafter, embodiments of the present invention will be described in detail.

  The adhesive tape for braille formation of the present invention is an adhesive tape for braille formation provided with an adhesive layer formed on one side of a base material layer, and contains thermally expandable microspheres in the adhesive layer. And

  In general, a plastic film (resin film) or sheet is appropriately used for the base material layer in the present invention.

  Examples of the component of the base material layer include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foamed sheets, metal foils, and laminates thereof. However, a plastic film is preferably used from the viewpoint of excellent surface smoothness.

  The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer. Examples thereof include a coalesced film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film. Especially, the film which can deform | transform following the spot-like foaming of the said adhesive layer, or the film which can be thermally deformed at the time of heat foaming of a thermally expansible microsphere is preferable.

  Examples of the base polymer constituting the resin film (base material layer) include, for example, various types of polyethylene from low density to high density, polyethylene resins such as isotactic polypropylene, atactic polypropylene, syndiotactic polypropylene, and TPO resins (olefins). Polyolefin resins such as thermoplastic elastomers), ethylene-vinyl acetate copolymers, polyvinyl chloride resins, polyester resins, polyamide resins, polycarbonate resins, (meth) acrylic polymers, urethane-acrylic hybrid polymer compositions, etc. Can do. Of these, urethane-acrylic hybrid polymer compositions and the like are preferable in the present invention because they do not require a step of heating to a high temperature (150 ° C. or higher) and are easily stretched. These base polymers may be used alone or in combination of two or more.

  The (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer, and (meth) acrylate refers to an acrylate and / or methacrylate.

  The urethane-acrylic hybrid polymer composition is a mixture of a urethane polymer having a polyol component and an isocyanate component and a (meth) acrylic polymer, or a copolymer thereof, and its production method is not particularly limited. For example, it can be manufactured by the following method.

  First, an acrylic component is polymerized using a polymerization initiator, and a polyisocyanate is reacted with the mixture of this (meth) acrylic polymer and a polyol component to synthesize a urethane prepolymer. At this time, a carboxyl group is introduced into the (meth) acrylic polymer or urethane prepolymer, the carboxyl group is neutralized and dispersed in water, the main chain is extended by the reaction of the isocyanate group, and the urethane-acrylic polymer An aqueous dispersion is obtained. If necessary, the composition of the acrylic component and the urethane-acrylic mixture ratio can be freely controlled by adding an acrylic monomer as the second component to the aqueous dispersion and polymerizing.

  Examples of the acrylic component include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, and 2-ethylhexyl (meth). Examples thereof include acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, isobornyl (meth) acrylate and the like. These acrylic components may be used alone or in combination of two or more.

  Along with these acrylic components, in a range not exceeding 50% by weight in the total monomers, for example, vinyl acetate, vinyl propionate, styrene, acrylamide, methacrylamide, maleic acid mono- or diester, styrene and its derivatives, N- Such as methylol acrylamide, glycidyl acrylate, glycidyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, oligoester acrylate, ε-caprolactone acrylate, etc. A monomer may be used. Selection of the monomer used for these acrylic components is appropriately determined in consideration of the characteristics of the high molecular weight obtained. These monomers may be used alone or in combination of two or more.

  The polyol component has at least two hydroxyl groups in one molecule, and examples thereof include low molecular weight polyols and high molecular weight polyols. These polyols may be used alone or in combination of two or more.

  Examples of the low molecular weight polyol include divalent alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and hexamethylene glycol, and trivalent alcohols such as trimethylolpropane, glycerin, and pentaerythritol.

  As the high molecular weight polyol, for example, polyether polyol obtained by addition polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, or the like, or the above dihydric alcohol, dipropylene glycol, 1,4-butanediol, 1,6 -Polyester polyols, acrylic polyols, carbonate polyols, epoxy polyols, caprolactone polyols, and the like consisting of polycondensates of hexanediol, neopentyl glycol and the like with dibasic acids such as adipic acid, azelaic acid, and sebacic acid.

  The molecular weight of the polyol component is preferably such that the number average molecular weight measured by gel permeation chromatography (GPC) is in the range of 500 to 4,000. If the molecular weight of the polyol component is too small, the resulting polymer becomes too hard, and if the molecular weight is too large, the dispersibility in water tends to be poor.

  Examples of the isocyanate component include aromatic, aliphatic and alicyclic diisocyanates. If necessary, tri or more polyisocyanates may be used. Among these, from the viewpoint of rapid reaction with polyol and suppression of reaction with water, examples of the isocyanate compound include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, cyclopentylene diisocyanate, and cyclohexane. Addition of alicyclic isocyanates such as xylene diisocyanate and isophorone diisocyanate, aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer Product (trade name Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene diisocyanate trimer adduct (trade name Coronate HL, JP Made of Polyurethane Industry Co., Ltd.), an isocyanurate of hexamethylene diisocyanate (trade name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) isocyanate adducts such as, such as diisocyanate adduct of the polyol, and the like. Of these, alicyclic diisocyanates such as isophorone diisocyanate, cyclohexane-1,4-diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate are preferable. These components may be used alone or in combination of two or more.

  Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 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'-dimethyleneisobutylamidine), 2,2 Azo initiators such as' -azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.), persulfates such as potassium persulfate and ammonium persulfate , Di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylper Oxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3 3-tetramethylbutylperoxy-2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) Peroxides such as cyclohexane, t-butyl hydroperoxide, cumene hydroperoxide, and hydrogen peroxide, peroxides and sodium bisulfite, peroxides and sodium ascorbate And redox initiators that combine reducing agents DOO but it can not be construed as being limited thereto. Moreover, the usage-amount of these polymerization initiators can be suitably selected according to the molecular weight of a polymer, etc.

  Further, the ratio of urethane and acrylic is preferably urethane / acrylic (wt%) = 10/90 to 80/20.

  The urethane-acrylic hybrid polymer composition thus produced is a material having both urethane cohesive force and acrylic stress relaxation property, and has a function as the adhesive tape substrate of the present invention.

  The thickness of the base material layer is usually 1 to 500 μm, preferably 1 to 300 μm, and preferably 5 to 100 μm, but is not limited thereto.

  The base material layer may contain conductive powder or magnetic powder and can be induction-heated via high frequency. Moreover, you may have a conductor layer and a magnetic body layer in a base material layer or the surface.

  In addition to the above components, the base material layer may further include various tackifiers such as phenol resin, terpene-phenol resin, terpene resin, xylene resin, rosin and hydrogenated rosin, and inorganic such as calcium carbonate and carbon black. Fillers, lubricants, anti-aging agents, dyes, colorants, pigments, surfactants, plasticizers, antifoaming agents, flame retardants, light stabilizers, thixotropic agents, UV absorbers, low molecular weight polymers, surface lubricants, Leveling agents, antioxidants, polymerization inhibitors, heat stabilizers, hydrolysis stabilizers, metal powders, particles, foils, and the like can be used as appropriate. These components may be used alone or in combination of two or more.

  Moreover, for the purpose of improving the adhesiveness with the pressure-sensitive adhesive layer, the surface of the pressure-sensitive adhesive layer may be subjected to various discharge treatments, anchor coating treatments, and the like. In particular, in order to strongly adhere to the pressure-sensitive adhesive layer, it is preferable to use a chemical or physical treatment that oxidizes the surface by chromic acid treatment, ozone exposure, flame exposure, high piezoelectric exposure, or ionizing radiation treatment.

  The base material layer in the present invention has the above-described configuration.

  The thermally expandable microsphere in the present invention refers to a microsphere in which a substance that expands by gasification by heating is encapsulated in an elastic shell, and includes what is called a thermally expandable microcapsule.

  Examples of the substance that expands by gasification include isobutane, propane, and pentane. These substances may be used alone or in combination of two or more.

  In addition, as the substance forming the shell, for example, a heat-meltable substance or a substance that breaks due to thermal expansion is used, and more specifically, for example, vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl Examples thereof include methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. These substances may be used alone or in combination of two or more.

  The heat-expandable microspheres can be appropriately produced by a known microencapsulation method such as a coacervation method or an interfacial polymerization method.

  As the thermally expandable microspheres, for example, commercially available products such as Matsumoto Microsphere (trade name: manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) can be used.

  The thermally expandable microspheres preferably have an average particle size before expansion of 10 μm or more and 90% by weight or more of particle size of 5 μm or more, an average particle size before expansion of 18 μm or more, and 90%. The weight percent or more is more preferably 10 μm or more, but not limited thereto.

  In view of the degree of expansion of the heat-expandable layer by heat treatment, the thermally expandable microspheres that can be preferably used do not burst by foaming until the volume expansion coefficient is 5 times or more, further 7 times or more, particularly 10 times or more. Things are used.

  The thermally expandable microspheres are preferably those that thermally expand at 100 to 500 ° C, more preferably those that thermally expand at 140 to 400 ° C, and still more preferably those that thermally expand at 200 to 300 ° C. If the expansion start temperature is too low, expansion and rupture of the thermally expandable microspheres may occur even at a temperature in the base material layer manufacturing process.

  In the present invention, a known foaming agent may be used in combination with the thermally expandable microspheres.

  Although it does not restrict | limit especially as a foaming agent, For example, an inorganic type foaming agent and an organic type foaming agent are mention | raise | lifted. These foaming agents may be used alone or in combination with thermally expandable microspheres, or two or more may be mixed and used in combination with thermally expandable microspheres.

  Examples of the inorganic foaming agent include ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, azides and the like.

  Examples of the organic foaming agent include N-nitroso compounds (N, N′-dinitrosopentamethylenetetramine, N, N′-dimethyl-N, N′-dinitrosotephthalamide, etc.), azo compounds (for example, , Azobisisobutyronitrile, azodicarboxylic acid amide, barium azodicarboxylate, etc.), fluorinated alkanes (eg, trichloromonofluoromethane, dichloromonofluoromethane, etc.), hydrazine compounds (eg, paratoluenesulfonyl hydrazide, Diphenylsulfone-3,3′-disulfonylhydrazide, 4,4′-oxybis (benzenesulfonylhydrazide), allylbis (sulfonylhydrazide, etc.), semicarbazide compounds (for example, p-toluylenesulfonyl semicarbazide, 4,4′- Such Kishibisu (benzenesulfonyl semicarbazide)), triazole compound (e.g., 5-morpholyl-1,2,3,4-thiatriazole, etc.) and the like.

  The present invention is characterized in that the pressure-sensitive adhesive layer contains the thermally expandable microspheres.

  The adhesive tape for braille formation of this invention forms the adhesive layer which consists of an adhesive containing the said thermally expansible microsphere on the single side | surface on the said base material layer.

  The pressure-sensitive adhesive layer in the present invention is not particularly limited, but is formed of a pressure-sensitive adhesive that allows expansion and / or expansion when the heat-expandable microspheres are expanded by heat treatment. It needs to be one that does not constrain expansion as much as possible.

  As the above-mentioned pressure-sensitive adhesive, known ones can be used without particular limitation. For example, rubber-based pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives based on various synthetic rubbers, acrylic pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives , Silicone adhesives polyester adhesives, polyamide adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, styrene / diene block copolymer adhesives, hot-melt resins having a melting point of about 200 or less Various pressure-sensitive adhesives such as those having improved creep characteristics by blending can be used. These pressure-sensitive adhesives may be used alone or in combination of two or more.

  Among them, in general, rubber-based pressure-sensitive adhesives based on natural rubber and various synthetic rubbers as well as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (meth) acrylate , I-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, amyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (Meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, pentadec (Meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate and other (meth) acrylates having 20 or less carbon atoms as constituent components (Meth) acrylic polymer (these (meth) acrylates may be polymerized singly or in combination of two or more) and an acrylic pressure-sensitive adhesive having a base polymer is used. It is done.

  The (meth) acrylic polymer can be appropriately selected from other components as a monomer for the purpose of modifying cohesive force, heat resistance, crosslinkability, and the like, if necessary.

  As other components, the Tg is 0 ° C. or lower (usually −100 ° C. or higher) for the reason that it is easy to balance the adhesive performance, and the sulfonic acid group-containing monomer, phosphoric acid group-containing monomer, and cyano group-containing monomer are appropriately used. , Vinyl ester, aromatic vinyl compound and other cohesive strength / heat resistance improving components, carboxyl group-containing monomers, acid anhydride group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, amino group-containing monomers, imide group-containing A component having a functional group that functions as an adhesive strength improvement or a crosslinking base, such as a monomer, an epoxy group-containing monomer, N-acryloylmorpholine, and vinyl ethers can be used. Other components can be used alone or in combination of two or more.

  Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth). Examples include acryloyloxynaphthalene sulfonic acid and sodium vinyl sulfonate.

  Examples of the phosphate group-containing monomer include 2-hydroxyethyl acryloyl phosphate.

  Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

  Examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl laurate, and the like.

  Examples of the aromatic vinyl compound include styrene, chlorostyrene, chloromethyl styrene, α-methyl styrene, other substituted styrenes, and the like.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

  Examples of the acid anhydride group-containing monomer include maleic anhydride, itaconic anhydride, and acid anhydride bodies of the above carboxyl group-containing monomers.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl ( (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, vinyl Examples thereof include alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-butyl (meth) acrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N. -Diethylmethacrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide, N-vinylpyrrolidone, methylvinylpyrrolidone and the like.

  Examples of amino group-containing monomers include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, And (meth) acryloylmorpholine.

  Examples of the imide group-containing monomer include N-cyclohexylmaleimide, N-impropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, and other maleimide monomers, N-methylitaconimide, N-ethylitaconimide, and N-butyl. Itaconimide monomers such as itacimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, N- (meth) acryloyloxymethylene succinimide, N- (meta ) Succinimide monomers such as acryloyl-6-oxyhexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide.

  Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.

  Examples of vinyl ethers include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and the like.

  Examples of other monomers include alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, vinyl (meth) acrylates such as vinyl acetate and vinyl propionate, N-vinylcaprolactam, and vinyl. N-vinylcarboxylic acid amides such as pyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene Glycol-based acrylic ester monomers such as glycol (meth) acrylate and methoxypolypropylene glycol (meth) acrylate , Tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate, acrylic acid ester monomers such as 2-methoxyethyl (meth) acrylate, hexanediol di (meth) acrylate and (poly) ethylene glycol Di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate , Dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, etc. Chromatography, isoprene, butadiene, isobutylene and the like.

  The (meth) acrylic polymer can be obtained by a polymerization method generally used as a synthesis method of (meth) acrylic polymer such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization.

  The obtained (meth) acrylic polymer may be any of a random copolymer, a block copolymer, a graft copolymer, an alternating copolymer, and the like.

  The other polymerizable monomer components described above may be used alone or in admixture of two or more, but the total content is all structural units of the (meth) acrylic polymer The polymerizable monomer component is preferably less than 90 parts by weight and more preferably less than 80 parts by weight with respect to 100 parts by weight. By using the above-mentioned other polymerizable monomer components, good adhesion to the adherend can be appropriately adjusted.

  The polymerization initiator, chain transfer agent, emulsifier and the like used for the synthesis (polymerization) of the (meth) acrylic polymer are not particularly limited and can be appropriately selected and used.

  Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 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'-dimethyleneisobutylamidine), 2,2 Azo initiators such as' -azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.), persulfates such as potassium persulfate and ammonium persulfate , Di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylper Oxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3 3-tetramethylbutylperoxy-2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) Peroxides such as cyclohexane, t-butyl hydroperoxide, hydrogen peroxide, peroxides and sodium bisulfite, peroxides and sodium ascorbate For example, combined redox initiators can be used. Not shall.

  The polymerization initiator may be used alone or as a mixture of two or more, but the total content is 0.005 to 1 part by weight with respect to 100 parts by weight of the monomer. Is preferably about 0.02 to 0.5 parts by weight.

  In the present invention, a chain transfer agent may be used in the polymerization. By using a chain transfer agent, the molecular weight of the (meth) acrylic polymer can be appropriately adjusted.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, and α-methylstyrene dimer. It is done.

  These chain transfer agents may be used alone or as a mixture of two or more, but the total content is 0.01 to 15 parts by weight with respect to 100 parts by weight of the monomer. About a part.

  Examples of the emulsifier in the case of emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, and polyoxyethylene. Nonionic emulsifiers such as alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene-polyoxypropylene block polymers, and the like can be mentioned. These emulsifiers may be used alone or in combination of two or more.

  Furthermore, as reactive emulsifiers, as emulsifiers into which radical polymerizable functional groups such as propenyl groups and allyl ether groups are introduced, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05 BC-10, BC-20 (Daiichi Kogyo Seiyaku Co., Ltd.), Adekaria Soap SE10N (Asahi Denka Kogyo Co., Ltd.) and the like. Reactive emulsifiers are preferable because they are incorporated into the polymer chain after polymerization and thus have improved water resistance. The amount of the emulsifier used is more preferably 0.3 to 5 parts by weight and 0.5 to 1 part by weight with respect to 100 parts by weight of the monomer in view of polymerization stability and mechanical stability.

  The (meth) acrylic polymer used in the present invention has a weight average molecular weight of 100,000 to 3,000,000, preferably 300,000 to 1,000,000, more preferably 500,000 to 900,000. When the weight average molecular weight is less than 100,000, the adhesive composition tends to have adhesive residue due to the reduced cohesive force of the pressure-sensitive adhesive composition, and the tendency to prevent floating / peeling tends to deteriorate. On the other hand, when the weight average molecular weight exceeds 3 million, the viscosity becomes too high and the coating property tends to be poor. A weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

  As the crosslinking agent used in the pressure-sensitive adhesive layer, an isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative, a metal chelate compound, or the like is used. Among these, an isocyanate compound and an epoxy compound are particularly preferably used mainly from the viewpoint of obtaining an appropriate cohesive force. In particular, in the production of a polymer, a hydroxyl group is introduced into the polymer by copolymerizing a hydroxyl group-containing monomer such as 2-hydroxyethyl acrylate, and a polyisocyanate compound is used as a crosslinking agent for the polymer. preferable. These crosslinking agents may be used alone or in combination of two or more.

  Examples of the isocyanate compound include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic isocyanates such as 4,4′-diphenylmethane diisocyanate and xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene Diisocyanate trimer adduct (trade name Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), isocyanurate of hexamethylene diisocyanate Body (trade name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) isocyanate adducts such as, such as diisocyanate adduct of the polyol, and the like. These compounds may be used alone or in combination of two or more.

  Examples of the epoxy compound include N, N, N ′, N′-tetraglycidyl-m-xylenediamine (trade name: TETRAD-X, manufactured by Mitsubishi Gas Chemical Company) and 1,3-bis (N, N-diglycidyl). Aminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company, Inc.). These compounds may be used alone or in combination of two or more.

  Examples of the melamine-based resin include hexamethylol melamine.

  Examples of the aziridine derivative include a commercial product name HDU (manufactured by Mutual Pharmaceutical Company), a product name TAZM (manufactured by Mutual Pharmaceutical Company), and a product name TAZO (manufactured by Mutual Pharmaceutical Company). These compounds may be used alone or in combination of two or more.

  Examples of the metal chelate compound include aluminum, iron, tin, titanium, and nickel as metal components, and acetylene, methyl acetoacetate, and ethyl lactate as chelate components. These compounds may be used alone or in combination of two or more.

  The content of the crosslinking agent used in the pressure-sensitive adhesive is usually about 0.01 to 5 parts by weight with respect to 100 parts by weight of the base polymer such as a (meth) acrylic polymer.

  The amount of thermally expandable microspheres in the pressure-sensitive adhesive layer is preferably 1 to 300 parts by weight, preferably 10 to 200 parts by weight, based on 100 parts by weight of the base polymer constituting the pressure-sensitive adhesive layer. It is more preferable that it is contained in an amount of 25 to 150 parts by weight. If the blending amount of the thermally expandable microspheres is less than 1 part by weight, the expansion ratio becomes low, a sufficient foaming action cannot be obtained, the thickness change after heating becomes small, and it may be difficult to read Braille. is there. On the other hand, if it exceeds 300 parts by weight, the expansion ratio becomes high, and sufficient tape base material strength may not be maintained.

  The formation method in particular of an adhesive layer is not restrict | limited, The method used normally can be used suitably.

  For example, if necessary, thermally expandable microspheres and the like can be mixed with a base polymer using a solvent, and the mixture can be used by a melt extrusion method, a coating method, or a calendering method. In addition, it is necessary to form it below the expansion | swelling or foaming start temperature of a thermally expansible sphere.

  More specifically, for example, the pressure-sensitive adhesive containing the thermally expandable microspheres is applied to a separator (or base material layer), and the polymerization solvent is dried and removed to remove the pressure-sensitive adhesive layer from the separator (or base material layer). It is produced by a method of forming on top, or a method of applying a pressure-sensitive adhesive on another base material, drying and removing the polymerization solvent and transferring the pressure-sensitive adhesive layer to a separator (or base material layer), etc. . Further, after the formation of the pressure-sensitive adhesive layer, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction.

  Moreover, in the said formation, the well-known method used for manufacture of adhesive sheets is used suitably. Specifically, for example, methods such as roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, extrusion coat method using a die coater, etc. Can be used as appropriate.

  Moreover, the solvent arbitrarily used for application | coating of an adhesive can use a well-known thing without a restriction | limiting in particular. For example, aromatic hydrocarbon solvents such as toluene, xylene and mesitylene, aliphatic carboxylic acid solvents such as ethyl acetate and butyl acetate, aliphatic hydrocarbon solvents such as hexane, heptane and octane, acetone, methyl ethyl ketone and methyl Examples thereof include ketone solvents such as isobutyl ketone. These solvents may be used alone or in combination of two or more.

  Further, the content of the solvent in the polymer solution is usually about 10 to 70% by weight.

  The pressure-sensitive adhesive layer is preferably heat-treated, whereby the thickness of the pressure-sensitive adhesive layer can be preferably 1.1 to 40 times that before the heat treatment, and preferably 2 to 10 times. More preferably, it can further be 5-8 times. If the expansion amount is less than 1.1 times, braille is difficult to discriminate. On the other hand, if the expansion amount is more than 40 times, the tape base material strength may be lowered.

  Although the thickness of the said adhesive layer should just be set suitably according to a use, generally it is used at 5-100 micrometers, it is preferable that it is 20-60 micrometers, and it is more preferable that it is 30-50 micrometers. If it is smaller than 5 μm, the uneven deformation degree of the pressure-sensitive adhesive layer by the heat treatment is too small, and braille identification may be difficult. In addition, the thickness of the pressure-sensitive adhesive layer may be formed as a layer thicker than the average particle diameter of the heat-expandable microspheres, particularly as a layer thicker than the maximum particle diameter of the heat-expandable microspheres. From the viewpoint of achieving a stable adhesive force before heat treatment.

  The pressure-sensitive adhesive layer may contain conductive powder or magnetic powder and can be induction-heated via high frequency. Moreover, you may have a conductor layer and a magnetic body layer in the adhesive layer or on the surface.

  Furthermore, various tackifiers can be used as appropriate for the pressure-sensitive adhesive layer.

  Examples of the tackifying resin used in the present invention include rosin derivative resins, polyterpene resins, aliphatic petroleum resins, aromatic petroleum resins, aliphatic / aromatic hybrid resins, alkylphenol formaldehyde resins (oil phenols) used as tackifiers. Resin) having the specific characteristics described below. These compounds may be used alone or in combination of two or more.

  Examples of rosin derivative resins include rosin abietic acid, rosin parastrate, rosin neoabietic acid, rosin pimaric acid, rosin isopimaric acid, rosin dehydroabietic acid, and water additions thereof, and maleic acid adducts, metals thereof Examples include processed rosins such as salts, ester compounds with alcohols such as glycerin, pentaerythritol, ethylene glycol and diethylene glycol, and wood rosin, gum rosin, tall oil rosin and the like. These compounds may be used alone or in combination of two or more.

  Examples of the polyterpene resin include homopolymers such as α-pinene, β-pinene, limonene, and dipentene, or copolymers thereof, terpene phenol copolymers, and water additives thereof. These compounds may be used alone or in combination of two or more.

Examples of the aliphatic petroleum resins mainly are mentioned those purified C ₅ fraction by cationic polymerization among cracked fractions of petroleum naphtha, for example, Shisupiperiren, trans piperylene, isoprene, 2-methylbutene 2, dicyclopentadiene And the like, and copolymers thereof, water additives thereof and the like. These compounds may be used alone or in combination of two or more.

As the aromatic petroleum resin, mainly can be mentioned those purified C ₉ fraction was cationically polymerized among cracked fractions of petroleum naphtha, for example, styrene, indene, methyl indene, methyl styrene, coumarone (benzo [b] Furan) and the like, and homopolymers thereof, copolymers thereof, and water additives thereof. These compounds may be used alone or in combination of two or more.

Examples of the aliphatic / aromatic mixed resin, raised mainly blend of C ₅ fraction and C ₉ fraction among cracked fractions of petroleum naphtha is obtained by cationic polymerization e.g., dicyclopentadiene, dimethyl dicyclopentadiene, and a diene monomer (C ₅ fraction dimer), copolymers of styrene, indene, and the like of these hydrogenated product thereof. These compounds may be used alone or in combination of two or more.

  Examples of the alkylphenol formaldehyde resin (oil-based phenol resin) include novolak type and resol type. These compounds may be used alone or in combination of two or more.

  In the present invention, 1 to 25 parts by weight of the tackifying resin is contained with respect to 100 parts by weight of the base polymer, more preferably 1 to 10 parts by weight. More preferably, it is contained.

  Furthermore, in the above-mentioned pressure-sensitive adhesive layer, as optional components, in addition to the above-mentioned components, inorganic fillers such as calcium carbonate and carbon black, lubricants, anti-aging agents, dyes, colorants, pigments, surfactants, plasticizers, antifoaming agents Agent, flame retardant, light stabilizer, thixotropic agent, UV absorber, low molecular weight polymer, surface lubricant, leveling agent, antioxidant, polymerization inhibitor, heat stabilizer, hydrolysis stabilizer, metal powder, particles , Foils, etc. can be used as appropriate. These components may be used alone or in combination of two or more.

  Moreover, for the purpose of improving adhesiveness with the base material layer, various discharge treatments, anchor coat treatments, and the like may be applied to the pressure-sensitive adhesive layer surface.

  The pressure-sensitive adhesive layer in the present invention has the above-described configuration.

  Moreover, in the adhesive tape for braille formation of this invention, you may use a separator in order to protect an adhesive layer until it uses it.

  For the separator, if necessary, for example, a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agent, mold release and antifouling treatment with silica powder, acid treatment, alkali treatment, primer Anti-adhesive treatment such as treatment, anchor coating treatment, corona treatment, plasma treatment, ultraviolet treatment, coating type, kneading type, vapor deposition type, etc. can also be performed.

  As the separator used in the present invention, those conventionally used as separators can be appropriately used without particular limitation. Specifically, as a constituent material of the separator (release sheet), for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, paper products such as glassine paper, coated paper, and laminated paper, cloth, nonwoven fabric, etc. Examples thereof include a porous material, a net, a foam sheet, a metal foil, and appropriate thin leaves such as a laminate thereof, and a plastic film is preferably used from the viewpoint of excellent surface smoothness. The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer. Examples thereof include a coalesced film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The separator is usually removed as appropriate when the pressure-sensitive adhesive layer surface is used.

  In the Braille-forming pressure-sensitive adhesive tape of the present invention, when the pressure-sensitive adhesive layer is provided only on one side of the base material layer, for example, a separator is used on the surface opposite to the base material layer of the pressure-sensitive adhesive layer, or the base material The surface of the layer that is not in contact with the pressure-sensitive adhesive layer can be formed into a wound shape by subjecting the surface to a release liner coating such as a silicone resin or a fluorine resin.

  The adhesive tape for braille formation of this invention has the above structures.

  The adhesive tape for braille forming of the present invention has the above-described configuration, so that any part of the adhesive tape is necessary at the time of use after being attached to an adherend without greatly changing the adhesive force. It becomes possible to foam. Therefore, it is suitable for use in a braille label, a braille sheet, or the like.

  Moreover, the Braille label of the present invention is obtained by partially foaming the adhesive layer of the Braille-forming pressure-sensitive adhesive tape described above. By using such a braille label, it is possible to easily form braille at an arbitrary stage and not to lose a part of the braille display.

  Braille labels, braille tapes, etc. of the present invention can be exposed to the adhesive layer by peeling off the separator or developing the tape, and the adhesive layer can be applied to any place or part where the adherend is to be applied. it can. The braille can be formed at an appropriate stage according to the purpose of use, such as during the development of the braille label or the braille tape, or after the braille label or the braille tape is applied.

  On the other hand, the use method of the adhesive tape for braille formation of the present invention includes a step of attaching the adhesive tape for braille formation to an adherend, and then heat-treating the braille forming portion of the adhesive tape for braille formation. Forming the step. In such a method of use, braille can be formed by foaming any part of the pressure-sensitive adhesive tape at a necessary stage without greatly changing the adhesive strength during use after being attached to the adherend. By using the Braille-forming pressure-sensitive adhesive tape of the present invention, partial foaming can be easily performed by heat-treating only the part to be foamed after the adherend is attached.

  Furthermore, the method of using the adhesive tape for braille formation of the present invention includes a step of heat-treating a braille forming portion of the adhesive tape for braille formation to form braille, and then the adhesive tape for braille formation to an adherend. A step of attaching. In such a method of use, in use after being attached to the adherend after the heat treatment, braille is formed by foaming any part of the adhesive tape at a necessary stage without greatly changing the adhesive force before the heat treatment. Can be formed. By using the Braille forming pressure-sensitive adhesive tape of the present invention, partial foaming can be easily performed by heat-treating only the part to be foamed before attaching the adherend.

  In addition, the heat treatment step is performed according to the heat treatment conditions (heating temperature and heating) depending on the surface state of the adherend, the foaming temperature depending on the type of the thermally expandable microsphere, the base material, the adhesive, the heat resistance of the adherend, and the like. Treatment time) can be selected as appropriate. Further, by making the heat treatment conditions appropriately separated from the expansion and foaming start temperatures of the thermally expandable microspheres, in the step of forming the base material layer and / or the step of forming the pressure-sensitive adhesive layer, thermal expansion is performed. The risk of causing expansion and foaming in each process of the conductive microsphere can be reduced, and the range of selection of material and process temperature can be expanded.

  In general, the heating temperature is preferably 100 to 500 ° C, more preferably 120 to 400 ° C, and further preferably 200 to 300 ° C.

  The heat treatment time is generally preferably 0.1 to 300 seconds, more preferably 0.1 to 100 seconds, and further preferably 0.1 to 30 seconds. .

  For the heat treatment, for example, a soldering iron, a thermal transfer printer, or the like can be used as appropriate.

  Under these heat treatment conditions, the heat-expandable microspheres in the pressure-sensitive adhesive layer are usually expanded or foamed to deform the pressure-sensitive adhesive layer and the base material layer, thereby increasing the thickness of the Braille-forming pressure-sensitive adhesive tape.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, the evaluation item in an Example measured as follows.

<Adhesion measurement>
The prepared Braille-forming adhesive tape was attached to a stainless steel plate to prepare a test piece having a width of 20 mm and a length of 150 mm. Using the above test piece, in accordance with JIS Z 0237, before heat treatment and after heat treatment (heat treatment: braille with a diameter of 5 mm is performed by randomly heating 30%, 20%, and 10% of the total area. For each, the adhesive strength (180 degree peel adhesive force) when peeled at a peeling speed of 300 mm / min and a peeling angle of 180 ° was measured with a Tensilon type peel tester. The measurement was performed in an environment of 23 ° C. × 55% RH. When the value is 5 N / 25 mm or more, it can be said that it is difficult to leave the adherend.

<Evaluation of Braille readability>
The produced Braille-forming adhesive tape was affixed to a cardboard and brought into contact with a metal bar heated to 180 ° C. for 10 seconds to foam in a circular shape having a diameter of 5 mm, thereby producing a Braille-shaped uneven structure. The evaluation criteria were as follows.
・ If more than 8 out of 10 can be identified: ○
・ If less than 8 out of 10 people can be identified: ×

<Measurement of thickness of Braille forming adhesive tape (Braille label)>
The thickness of the adhesive tape for braille formation (braille label) before and after foaming of each test piece when the above-mentioned adhesive strength measurement was performed was measured with a dial gauge (manufactured by PEACOCK, dial checkness gauge).

[Example 1]
50 parts by weight of heat-expandable microspheres (Matsumoto Yushi Co., Ltd., Matsumoto Microsphere) with an average particle size of 20 μm are mixed with 100 parts by weight of solid content of an acrylic adhesive, and one side of a polyester film (thickness: 25 μm) And dried to form an acrylic pressure-sensitive adhesive layer having a thickness of 40 μm. Subsequently, the acrylic pressure-sensitive adhesive layer was bonded to a separator (manufactured by Nitto Denko Corporation) to obtain a Braille-forming pressure-sensitive adhesive tape having a total thickness of 65 μm.

  The pressure-sensitive adhesive is a terpene-based solution in a toluene solution of 100 parts by weight of a (meth) acrylic copolymer (A) comprising 50 parts by weight of butyl acrylate, 50 parts by weight of ethyl acrylate, and 5 parts by weight of acrylic acid. It is prepared by blending 30 parts by weight of a tackifier (Yasuhara Chemical Co., Ltd., YS Resin PX1000) and 3 parts by weight of a polyurethane-based crosslinking agent (Nihon Polyurethane Co., Ltd., Coronate L).

[Example 2]
50 parts by weight of thermally expandable microspheres (Matsumoto Yushi Co., Ltd., Matsumoto Microsphere) having an average particle size of 20 μm are mixed with 100 parts by weight of a solid content of a rubber-based adhesive, and one side of a polyester film (thickness: 25 μm) And dried to form an acrylic pressure-sensitive adhesive layer having a thickness of 40 μm. Subsequently, the acrylic pressure-sensitive adhesive layer was bonded to a separator (manufactured by Nitto Denko Corporation) to obtain a Braille-forming pressure-sensitive adhesive tape having a total thickness of 65 μm.

  The pressure-sensitive adhesive was prepared by adding 100 parts by weight of a natural rubber, 100 parts by weight of a terpene-based tackifier (manufactured by Yasuhara Chemical Co., Ltd., YS Resin PX1000) and 3 parts by weight of a polyurethane-based cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., Coronate L). It is prepared by blending parts.

  According to the above method, measurement of adhesive strength before and after heat treatment, evaluation of Braille readability, and thickness measurement of the adhesive tape for braille formation were performed. The obtained results are shown in Table 1.

  From the results of Table 1 above, when the braille forming pressure-sensitive adhesive tape having the configuration of the present invention was used (Examples 1 and 2), the adhesive strength was not significantly changed before and after the heat treatment step (and further 5 N / The value of 25 mm or more was maintained), and the pressure-sensitive adhesive layer was effectively expanded, and a Braille structure (uneven structure) was able to be produced on the surface of the substrate layer.

  Therefore, the pressure-sensitive adhesive composition of the present invention can foam any part of the pressure-sensitive adhesive tape at a necessary stage without greatly changing the pressure-sensitive adhesive force at any stage before and after being attached to the adherend. It was confirmed that this was a possible Braille-forming adhesive tape (Braille label).

Claims (9)

  A Braille-forming pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer formed on one side of a base material layer, wherein the pressure-sensitive adhesive layer contains thermally expandable microspheres.   The braille forming pressure-sensitive adhesive tape according to claim 1, wherein the base material layer is made of a film that can be deformed following the spot-like foaming of the pressure-sensitive adhesive layer.   The pressure-sensitive adhesive tape for braille formation according to claim 1 or 2, wherein the base material layer is made of a film that can be thermally deformed when the thermally expandable microspheres are heated and foamed.   The adhesive tape for braille formation according to any one of claims 1 to 3, wherein 1 to 300 parts by weight of the thermally expandable microspheres are contained with respect to 100 parts by weight of the base polymer constituting the adhesive layer.   The adhesive tape for braille formation in any one of Claims 1-4 which can make the thickness of the said adhesive layer 1.1-40 times before heat processing by performing heat processing.   The braille label which made the adhesive layer of the adhesive tape for braille formation in any one of Claims 1-5 foamed partially.   The step of sticking the adhesive tape for braille formation according to any one of claims 1 to 5 to an adherend, and then the step of heat-treating the braille forming portion of the adhesive tape for braille formation to form braille. Use of the adhesive tape for braille formation characterized by including.   The step of heat-treating the braille forming part of the adhesive tape for braille formation according to any one of claims 1 to 5 to form braille, and then the step of attaching the adhesive tape for braille formation to an adherend. Use of the adhesive tape for braille formation characterized by including.   The usage method of the adhesive tape for braille formation of Claim 7 or 8 with which the process to heat-process is performed at 100-500 degreeC.