JP2005281564A - Adhesive composition and its manufacturing method, and sheet for carrying information - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition excellent in blocking resistance, and a sheet for carrying information. <P>SOLUTION: The adhesive composition comprises natural rubber fine particles, a radiation-curable compound and a filler non-affinitive to the natural rubber fine particles, where the filler comprises fine particles having a width of at least 0.1 μm and at most 15 μm. The manufacturing method of the adhesive composition comprises a mixing step for mixing a radiation-curable medium having the filler dispersed therein with an aqueous emulsion containing the natural rubber fine particles; and a medium-replacing step for removing water contained in the aqueous emulsion by vaporization under ventilation or reduced pressure while stirring the mixture to replace the medium where the natural rubber fine particles are dispersed from water to the radiation-curable medium, where the filler comprises the fine particles non-affinitive to the natural rubber fine particles and having a width of at least 0.1 μm and at most 15 μm. The sheet for carrying information comprises a substrate sheet and, formed thereon, a pressure-sensitive adhesive layer, where the pressure-sensitive adhesive layer comprises a cured product of the adhesive composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adhesive composition containing natural rubber-based fine particles, and particularly to an adhesive composition suitable as a pressure-sensitive adhesive composition. The present invention also relates to an information carrying sheet using this adhesive composition. More specifically, the information-carrying sheet having confidentiality and confidentiality such as a folding sheet and a superposed sheet in which the surface overlapped by folding and cutting is used as an information-carrying surface, an arrangement sheet that can be expanded in size, and copy paper The present invention relates to an information carrying sheet that adheres the overlapping surfaces thereof, such as office sheets.

  Conventionally, in an information carrying sheet that carries information on a superposed surface, the entire superposed surface is partially or partially patterned so that the superposed surfaces are usually bonded to each other so that the superposed surfaces adhere to each other. Alternatively, a pressure-sensitive adhesive layer is linearly provided. This pressure-sensitive adhesive is also referred to as a self-adhesive pressure-sensitive adhesive. By applying a strong pressure in a state where the adhesive layers are in contact with each other, the respective polymers self-diffusion or adhere due to the anchor effect. Thus, permanent adhesiveness and re-peeling adhesiveness are realized depending on the type of composition and the degree of pressurization.

  As an example of such an information-carrying sheet, a postcard system having confidentiality and confidentiality has been put into practical use and is widely used.

  Examples of postcard systems that have confidentiality and confidentiality include postcards that contain various information such as personal requirements, print information, and print information, folded, stacked, or stacked together. is there.

  In these postcard systems, the adhesive layer is detachably pressed in various overlay modes, and the confidentiality and confidentiality information is concealed, then mailed, and the recipient peels the overlapped surface again to conceal it. Information is read.

  In addition, as another example of a postcard system having confidentiality and confidentiality, the adhesive layer is pressure-bonded so that it cannot be peeled in various overlapping modes, and confidentiality information is concealed and then mailed to the recipient. In some cases, the concealment information is read by removing and removing the cover and reopening the overlapping surface.

  As an information carrying sheet used for a postcard system or the like, for example, Patent Document 1 (Japanese Patent Laid-Open No. 4-59395) discloses a non-releasable adhesive base (natural rubber latex) ) And a layer of an adhesive composition made of a particulate filler exhibiting non-affinity for the adhesive base is disclosed. In Patent Document 2 (Japanese Patent Laid-Open No. 10-265742), an acrylic cured material cured by radiation such as ultraviolet rays, electron beams, X-rays, i-rays, and g-rays is used as a pressure-sensitive adhesive. Is disclosed. Furthermore, Patent Document 3 (Japanese Patent Laid-Open No. 2004-2534) discloses an adhesive composition that is radiation curable and contains natural rubber-based fine particles and a carboxyl group-containing acrylic compound.

JP-A-4-59395 Japanese Patent Laid-Open No. 10-265742 JP 2004-2534 A

  Thus, although the adhesive used for the information carrying sheet is known, it has been demanded to further improve the blocking resistance. That is, when the information carrying sheets are stacked and stored, it has been demanded that the adhesive surface does not adhere even under more severe conditions.

  Further, if the adhesive layer can be formed by printing the adhesive on the base sheet by offset printing, the industrial utility value is high. This is because offset printing is widely used, and an adhesive layer can be provided with a desired pattern in a base sheet shape with high accuracy. However, when a conventional adhesive is printed on a base sheet by offset printing, the obtained adhesive layer may be inferior in blocking resistance. That is, an adhesive suitable for forming an adhesive layer by offset printing has been demanded.

  An object of the present invention is to provide an adhesive composition suitable for forming a pressure-sensitive adhesive layer, in particular, having excellent blocking resistance of the obtained adhesive layer.

  Another object of the present invention is to provide an adhesive composition having excellent blocking resistance of the adhesive layer even when the pressure-sensitive adhesive layer is formed by offset printing. An adhesive composition for offset printing capable of forming a pressure adhesive layer is provided.

  Another object of the present invention is to provide a method for producing an adhesive composition capable of suitably producing such an adhesive composition.

  Another object of the present invention is to provide an information carrying sheet having an adhesive layer excellent in blocking resistance.

According to the present invention, natural rubber-based fine particles, a radiation curable compound, and a non-affinity filler for the natural rubber-based fine particles,
An adhesive composition is provided in which the filler is fine particles having a width of 0.1 μm or more and 15 μm or less.

  This adhesive composition is particularly suitable for offset printing.

  In the adhesive composition, the filler is preferably at least one selected from the group consisting of a silica-based filler, a talc-based filler, and a silicon-based filler.

  The said adhesive composition WHEREIN: The said filler is a silica type filler, Comprising: This silica type filler is included in the ratio of 5 to 30 mass parts with respect to 100 mass parts of said radiation-curable compounds. preferable.

  In the adhesive composition, the filler is a talc-based filler, and the talc-based filler is included at a ratio of 5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the radiation curable compound. preferable.

  The said adhesive composition WHEREIN: The said filler is a silicon type filler, Comprising: This silicon type filler is included in the ratio of 2 to 8 mass parts with respect to 100 mass parts of said radiation-curable compounds. preferable.

According to the present invention, a mixing step of mixing a radiation curable medium in which a filler is dispersed and a water-based emulsion containing natural rubber-based fine particles; and stirring or stirring the mixture obtained under the mixing step A medium replacement step of vaporizing and removing the water contained in the aqueous emulsion and replacing the medium in which the natural rubber fine particles are dispersed with water from the radiation curable medium;
There is provided a method for producing an adhesive composition, wherein the filler is fine particles having a non-affinity with respect to the natural rubber-based fine particles and having a width of 0.1 μm or more and 15 μm or less.

In accordance with the present invention, having a pressure sensitive adhesive layer on a substrate sheet,
The pressure-sensitive adhesive layer is a cured product of an adhesive composition containing natural rubber fine particles, a radiation curable compound, and a filler,
An information-carrying sheet is provided in which the filler is fine particles having a non-affinity with respect to the natural rubber-based fine particles and a width of 0.1 μm to 15 μm.

  ADVANTAGE OF THE INVENTION By this invention, the adhesive composition excellent in the blocking resistance of the adhesive layer suitable for forming a pressure sensitive adhesive layer especially the obtained adhesive bond layer is provided.

  Further, the present invention provides an adhesive composition having excellent blocking resistance of the adhesive layer even when the pressure-sensitive adhesive layer is formed by offset printing, and suitably forms the pressure-sensitive adhesive layer by offset printing. An adhesive composition for offset printing is provided.

  By this invention, the manufacturing method of the adhesive composition which can manufacture such an adhesive composition suitably is provided.

  According to the present invention, an information carrying sheet having an adhesive layer excellent in blocking resistance is provided.

[Natural rubber fine particles]
Natural rubber-based fine particles are fine particles such as natural rubber-based rubber, which is the main component that develops adhesive force by pressure bonding. As natural rubber-based rubber, it has an isoprene skeleton, which is the main component of natural rubber, and is self-adhesive. Any of natural rubber and synthetic rubber may be used. Examples thereof include natural rubber and isoprene rubber.

  From the viewpoint of improving the dispersibility and compatibility of natural rubber-based fine particles in radiation curable media, as natural rubber-based fine particles, copolymers of natural rubber-based rubber and acrylic monomers, especially acrylic rubber-based natural rubber-based rubber A copolymer obtained by graft polymerization of a monomer is preferred.

  Examples of acrylic monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth ) 2-ethylhexyl acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, lauryl (meth) acrylate-tridecyl, tridecyl (meth) acrylate, cetyl (meth) acrylate -(Meth) acrylic acid esters such as stearyl, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate and phenyl methacrylate; (meth) acrylic acid amide and methylol (meth) acrylic acid (Meth) acrylic acid amides such as amide; Acrylic acid, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, butyl (meth) acrylate Reactive acrylic monomers such as aminoethyl, glycidyl (meth) acrylate and tetrahydrofurfuryl (meth) acrylate; ethylene di (meth) acrylate, diethylene glycol di (meth) acrylate, tri (meth) acrylate tri Ethylene glycol, di (meth) acrylic acid tetraethylene glycol, di (meth) acrylic acid decaethylene glycol, di (meth) acrylic acid pentadecaethylene glycol, di (meth) acrylic acid pentacontactor ethylene glycol, di (me ) Crosslinkable acrylic monomers such as butylene acrylate, allyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and diethylene glycol di (meth) acrylate phthalate These can be used, and two or more of these can be used in combination.

  In addition to improving the dispersibility of the natural rubber-based fine particles, in order to improve the fixability of the adhesive composition to the base sheet, the natural rubber-based fine particles are a co-polymer of natural rubber-based rubber and styrene-based monomer. It is also preferable to use a polymer, particularly a copolymer obtained by graft polymerization of a styrene monomer to natural rubber rubber.

  Styrene monomers include styrene, α-methylstyrene, p-methylstyrene, α-methyl-p-methylstyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene, chlorostyrene, bromostyrene, etc. These can be used, and two or more of these can be used in combination.

  From the above viewpoint, natural rubber rubber, acrylic monomer and styrene monomer copolymer, especially acrylic rubber and styrene monomer are graft-polymerized to natural rubber rubber. Things can also be used. Further, if necessary, two or more kinds of natural rubber fine particles can be used in combination.

  The reaction ratio between the natural rubber rubber and the acrylic monomer and / or styrene monomer is in the range of 1 to 80 parts by mass of the total amount of the acrylic monomer and styrene monomer with respect to 100 parts by mass of the natural rubber fine particles. It can be.

  In particular, it is preferable to use a copolymer of a natural rubber rubber and an acrylic monomer as the natural rubber fine particles. When an acrylic monomer is graft-polymerized with a natural rubber rubber, the rubber properties of the natural rubber rubber are modified into resin properties, and the dispersibility of the natural rubber fine particles in a radiation curable medium is improved. The stability of is excellent. From the viewpoint of exhibiting this effect excellently, it is preferable to use natural rubber-based fine particles obtained by graft polymerization of 15 parts by mass or more of an acrylic monomer to 100 parts by mass of natural rubber-based rubber. On the other hand, from the viewpoint of ease of production of the adhesive and from the viewpoint of adhesive strength of the adhesive composition, the acrylic is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, with respect to 100 parts by mass of the natural rubber rubber. Natural rubber-based fine particles obtained by graft polymerization of a monomer based on the above are used.

[Radiation curable medium, radiation curable compound]
The radiation curable medium is a medium in which natural rubber-based fine particles can be dispersed and is curable by radiation. As the radiation curable medium, a radiation curable compound can be used, or a mixture of the radiation curable compound and other components can be used. Examples of other components herein include surfactants and dispersants. The term “curing” as used in the present invention includes not only curing by the formation of a network structure but also a decrease in fluidity as the polymerization reaction proceeds.

  As the radiation curable compound, medium replacement (described in detail later) can be carried out satisfactorily, and those that are cured well by radiation can be used as appropriate. However, medium substitution, curability and the resulting pressure-sensitive adhesive layer can be used. From the viewpoint of performance, a radiation-curable acrylic compound and a cyclic ether-containing radiation-curable compound are preferable, and these can be used in combination as necessary.

  The radiation curable acrylic compound is preferably an oligomer having at least one acryloyl group or methacryloyl group from the viewpoint of realizing good performance of the adhesive composition and the pressure-sensitive adhesive layer. An oligomer having two or more acryloyl groups or methacryloyl groups is more preferable. Furthermore, in addition to these (meth) acryloyl groups, oligomers having simultaneously radical reactive unsaturated groups can also be used. Examples of such unsaturated groups include allyl groups and methallyl groups.

  The oligomer preferably has a weight average molecular weight of 30 to 1000, and oligoethylene glycol, epoxy resin oligomer, polyester resin oligomer, polyamide resin oligomer, urethane resin oligomer, oligovinyl alcohol, phenol resin oligomer and the like can be used. .

  Preferable specific examples of the radiation curable acrylic compound as described above include oligoethylene glycol di (meth) acrylate, nonylphenol EO modified (n = 4) acrylate, acrylic ester of epoxy resin oligomer (for example, diglycidyl of bisphenol A) Ether diacrylate), reaction product of epoxy resin oligomer, acrylic acid and methyltetrahydrophthalic anhydride, reaction product of epoxy resin oligomer and 2-hydroxyethyl acrylate, epoxy resin oligomer diglycidyl ether and diallylamine Reaction products, ring-opening copolymerization ester of glycidyl diacrylate and phthalic anhydride, ester of methacrylic acid dimer and polyol, polyacrylic acid, phthalic anhydride and propylene oxide Steal, reaction product of oligoethylene glycol, maleic anhydride and glycidyl methacrylate, reaction product of oligovinyl alcohol and N-methylolacrylamide, esterification of oligovinyl alcohol with succinic anhydride followed by addition of glycidyl methacrylate , Oligomer obtained by reacting pyromellitic dianhydride diallyl ester with p, p'-diaminodiphenyl, reaction product of ethylene-maleic anhydride copolymer and allylamine, methyl vinyl ether-maleic anhydride Reaction product of copolymer and 2-hydroxyethyl acrylate, further reaction with glycidyl methacrylate, oligooxyalkylene segment or saturated oligoester segment via urethane bond or Both are connected, urethane oligomer having an acryloyl group or a methacryloyl group at both ends, can be mentioned a terminal acrylic-modified isoprene rubber or butadiene rubber, among others, oligoethylene glycol di (meth) acrylate.

  Moreover, a photopolymerizable monomer can also be used as a radiation curable acrylic compound as needed. Examples of preferred photopolymerizable monomers include (meth) acrylic acid, (meth) acrylic acid esters such as alkyl, cycloalkyl, alkyl halide, alkoxyalkyl, hydroxyalkyl, aminoalkyl, tetrahydrofurfuryl, allyl, glycidyl, benzyl , Phenoxy acrylate, phenoxy methacrylate, alkylene glycol, mono or diacrylate and methacrylate of polyoxyalkylene glycol, trimethylolpropane triacrylate and methacrylate, pentaerythritol tetraacrylate and methacrylate, acrylamide, methacrylamide or derivatives thereof such as alkyl groups Acrylamide and methacrylamide, diacetate mono- or di-substituted with hydroxyalkyl groups Acrylamide and methacrylamide, N, N'alkylene bisacrylamide and methacrylamide can be exemplified.

  Further, particularly in applications where curing shrinkage is hindered, examples of radiation-curable acrylic compounds include isobornyl acrylate or methacrylate, norbornyl acrylate or methacrylate, dicyclopentenoxyethyl acrylate or methacrylate, dicyclopente. Dicyclopentenyl cinnamate such as acrylic acid ester or methacrylic acid ester of diethylene glycol dicyclopentenyl monoether, acrylic acid ester or methacrylic acid ester of oligooxyethylene or oligopropylene glycol dicyclopentenyl monoether, such as tenoxypropyl acrylate or methacrylate 3,9-Bi, such as dicyclopentenoxyethyl cinnamate, dicyclopentenoxyethyl monofumarate or difumarate (1,1-bismethyl-2-oxyethyl) -spiro [5,5] undecane, 3,9-bis (1,1-bismethyl-2-oxyethyl) -2,4,8,10-tetraoxaspiro [5 , 5] undecane, 3,9-bis (2-oxyethyl) -spiro [5,5] undecane, 3,9-bis (2-oxyethyl) -2,4,8,10-tetraoxaspiro [5,5 ] Mono- or diacrylate or mono- or dimethacrylate such as undecane, or mono- or diacrylate of ethylene oxide or propylene oxide addition polymer of these spiroglycols, or mono- or dimethacrylate, or these monoacrylates Or methyl ether of methacrylate, 1-azabicyclo [2,2,2] -3-octe Acrylate or methacrylate, bicyclo [2,2,1] -5-heptene-2,3-dicarboxyl monoallyl ester, dicyclopentadienyl acrylate or methacrylate, dicyclopentadienyloxyethyl acrylate or methacrylate, dihydro It is preferable to use dicyclopentadienyl acrylate or methacrylate.

  Moreover, a polyfunctional acrylic compound can also be used as a radiation-curable acrylic compound. Examples of the polyfunctional acrylic compound include (meth) acrylic ester of copolymerizable α, β-unsaturated polyvalent carboxylic acid, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, dimethacrylic acid Dimethacrylic acid alkylene glycol esters such as 1,4-butylene glycol and propylene glycol dimethacrylate, and trimethylolpropane EO-added triacrylate can be used.

  Further, if necessary, an acrylic monomer, an acrylic oligomer having a polymerization degree of 2 to 10, a mixture thereof and the like can be used in combination.

  Furthermore, what substituted the oligomer component of the radiation-curable acrylic compound by the monomer component like paracumylphenol EO modified (n = 1) acrylate can also be used as the radiation-curable acrylic compound.

  On the other hand, as the cyclic ether radiation curable compound, from the viewpoint of realizing good performance of the adhesive composition and the pressure-sensitive adhesive layer, and from the viewpoint of ring opening of the cyclic ether structure, 2 to 12 Cyclic ether-containing radiation curable compounds containing one or more cyclic ether structures containing carbon and 1 to 6 oxygen are preferred. Further, the carbon number is more preferably 6 or less, further preferably 4 or less, and the oxygen number is preferably 4 or less, and more preferably 2 or less. A cyclic ether radiation curable compound containing two or more cyclic ether structures is more preferable.

  More specifically, a crosslinked structure containing —O— is preferable as the cyclic ether structure, and a compound having a group having an epoxy ring such as a glycidyl group is preferable as the cyclic ether radiation-curable compound.

  Furthermore, in addition to the cyclic ether structure, a compound having a radical reactive unsaturated group at the same time can also be used. Examples of such an unsaturated group include acryloyl group, methacryloyl group, allyl group, and methallyl group.

  In addition, the group having the cyclic ether structure and the unsaturated group as described above may be bonded to the monomer component and the oligomer component from the viewpoint of realizing good performance of the adhesive composition and the pressure-sensitive adhesive layer. preferable.

  The oligomer component preferably has a weight average molecular weight of 50 to 1000, and uses oligoethylene glycol, epoxy resin oligomer, polyester resin oligomer, polyamide resin oligomer, urethane resin oligomer, oligovinyl alcohol, phenol resin oligomer, or the like. Can do.

  Examples of the compound in which a cyclic ether structure is bonded to these oligomer components include oligoethylene glycol diglycidyl ether.

  Moreover, as a kind of monomer component, the monomer of an oligomer component as described above is preferable, and as a compound in which a cyclic ether structure is bonded to such a monomer component, for example, ethylene glycol diglycidyl is exemplified by two glycidyl groups. An example of three ether and glycidyl groups is trimethylolpropane triglycidyl ether.

  Among the radiation curable compounds described above, two radiation-polymerizable functional groups are used in one molecule from the viewpoint of the balance between the polymerizability of the pressure-sensitive adhesive composition and the adhesiveness of the resulting pressure-sensitive adhesive layer. It is preferable to use one having a group. As the radiation polymerizable functional group, when the radiation curable compound is a radiation curable acrylic compound, it can be a (meth) acryloyl group or the like, and when the radiation curable compound is a cyclic ether radiation curable compound, It can be an epoxy group or the like.

  Furthermore, it is preferable to use a bifunctional radiation curable compound and at least one of a monofunctional radiation curable compound and a trifunctional radiation curable compound as the radiation curable compound. Here, monofunctional, bifunctional, and trifunctional mean that one, two, and three radiation-polymerizable functional groups exist in one molecule, respectively.

  In an adhesive layer in which an adhesive composition containing a monofunctional radiation compound in addition to a bifunctional radiation curable compound is cured, the elasticity of the adhesive layer is improved, and the adhesive layer is information due to brittleness. Peeling from the carrying sheet is suppressed. In an adhesive layer in which an adhesive composition containing a trifunctional radiation compound in addition to a bifunctional radiation curable compound is cured, the surface hardness of the adhesive layer is improved and the surface of the adhesive layer may be destroyed. It is suppressed. As a result, in any case, even when information is printed on the information-carrying sheet with a high-speed printer, the adhesive layer is prevented from being peeled off and the occurrence of waste. In an adhesive layer in which an adhesive composition containing a monofunctional radiation compound and a trifunctional radiation compound in addition to a bifunctional radiation curable compound is cured, the effects of both are exhibited and more preferable. In particular, the bifunctional radiation curable compound is preferably a bifunctional radiation curable monomer such as polyethylene glycol diacrylate (n = 13 to 14) having higher hydrophilicity, and the monofunctional radiation curable compound is morpholine acrylate. Monofunctional radiation curable monomers such as are preferred, and the trifunctional radiation curable compound is preferably a trifunctional radiation curable monomer such as trimethylolpropane (EO-modified or PO-modified) triacrylate. Here, EO and PO represent ethylene oxide and propylene oxide, respectively.

  In the adhesive composition, the ratio of the total amount of the radiation curable compound to 100 parts by mass of the natural rubber-based fine particles is preferably 50 parts by mass or more from the viewpoint of the performance of the obtained adhesive composition and the adhesive layer, and 80 parts by mass. Part or more is more preferable, 100 parts by mass or more is more preferable, on the other hand, 500 parts by mass or less is preferable, 300 parts by mass or less is more preferable, and 200 parts by mass or less is still more preferable. In addition, as needed, 2 or more types of radiation-curable compounds can also be used together, and it is preferable in this case that the total amount of a radiation-curable compound is in said range.

  When a bifunctional radiation curable compound and at least one of a monofunctional radiation curable compound and a trifunctional radiation curable compound are used as the radiation curable compound, the monofunctional radiation curable compound is a natural rubber-based compound. From the viewpoint of improving the elasticity of the adhesive layer with respect to 100 parts by mass of the fine particles, 20 parts by mass or more is preferable, 30 parts by mass or more is more preferable, and from the viewpoint of tackiness of the adhesive layer, 60 parts by mass or less is preferable. Less than the mass part is more preferable. The trifunctional radiation curable compound is preferably 20 parts by mass or more, more preferably 30 parts by mass or more from the viewpoint of improving the surface hardness of the adhesive layer with respect to 100 parts by mass of the natural rubber-based fine particles. 60 mass parts or less are preferable from a viewpoint of the adhesive force of a layer, and 50 mass parts or less are more preferable.

  Depending on the type of radiation curable compound to be used, a polymerization initiator can be appropriately included in the adhesive composition. Examples of the polymerization initiator include benzoin, benzoin ethyl ether, benzoin-n-propyl ether, benzoin-isopropyl ether, benzoin alkyl ethers such as benzoin isobutyl-ether, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, Examples include benzyl, diacetyl, diphenyl sulfide, eosin, thionine, 9,10-anthraquinone, 2-ethyl-9,10-anthraquinone, and methylbenzoylformate. These polymerization initiators may be used alone or in combination of two or more. The usage-amount can be 0.1-30 mass parts with respect to 100 mass parts of total amounts of a radiation-curable compound.

[Manufacture of adhesive composition]
Here, an example of a method for producing the adhesive composition of the present invention will be described with reference to FIG.

  First, as shown in FIG. 1A, an aqueous emulsion 31 containing, for example, 40% by mass to 80% by mass of natural rubber-based fine particles 30 is added to a radiation curable medium 32 in which a filler is dispersed. The water-based emulsion is an emulsion in which the dispersion medium is water, and here, natural rubber fine particles are dispersed in water.

  This is mixed and the mixture 33 is heated using, for example, a warm bath 34 or the like as shown in FIG. By heating, water as a medium of the water-based emulsion is vaporized and gradually removed out of the mixture. As the water decreases, the dispersion medium is replaced with water by a radiation curable medium (FIG. 1C).

  A radiation curable compound may be used as it is as a radiation curable medium, or when preparing an adhesive composition containing other components such as a surfactant and a dispersant, the other components are mixed with the radiation curable compound. Thus, a radiation curable medium can be formed, and a filler can be dispersed therein, and then mixed with an aqueous emulsion to replace the medium. In some cases, after mixing the radiation curable compound and the aqueous emulsion and replacing the medium, the filler and other components may be dispersed or mixed.

  When this method is actually performed, the viscosity of the mixture increases as the water decreases, and when the dispersion medium is replaced, the viscosity of the mixture rapidly decreases. Such a sudden change in viscosity is considered to be caused by a phase transition. By adopting this method, the occurrence of aggregation of natural rubber fine particles is suppressed, and natural rubber fine particles are well dispersed. The obtained adhesive composition can be obtained.

  In addition to the dispersibility of the natural rubber fine particles, the average particle size of the natural rubber fine particles is 0 from the viewpoint of the performance of the resulting adhesive composition and the adhesive layer and from the viewpoint of suitability for offset printing. 0.01 μm or more is preferred, 0.03 μm or more is more preferred, 0.05 μm or more is more preferred, while 5 μm or less is preferred, 1 μm or less is more preferred, and 0.5 μm or less is even more preferred. The average particle diameter is measured on the basis of weight using a light scattering method or the like.

  Further, when the above-described method is adopted, the dispersion of the natural rubber fine particles is kept well without removing water as a medium from the natural rubber fine particle-containing aqueous emulsion or drying the natural rubber fine particles. The dispersion medium can be replaced directly. As a result, the moisture content of the resulting adhesive composition can be easily lowered, specifically, preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 1% by mass or less. Can do.

  From the viewpoint of obtaining an adhesive composition in which natural rubber-based fine particles having a desired average particle diameter are excellently and uniformly dispersed and water content is excellent and low, a radiation curable medium with respect to 100 parts by mass of the natural rubber-based fine particle-containing aqueous emulsion. The ratio is preferably 25 parts by mass or more, more preferably 40 parts by mass or more, still more preferably 50 parts by mass or more, while 250 parts by mass or less is preferable, 150 parts by mass or less is more preferable, and 100 parts by mass. The following is more preferable.

  Further, from the viewpoint of obtaining an adhesive composition in which natural rubber fine particles having a desired average particle diameter are excellently and uniformly dispersed and have a low moisture content, the temperature at which the water content of the aqueous emulsion containing natural rubber fine particles is evaporated is 20 ° C. or higher, preferably 30 ° C. or higher, more preferably 40 ° C. or higher, while 80 ° C. or lower is preferable, 60 ° C. or lower is more preferable, and 50 ° C. or lower is still more preferable. For this reason, the temperature of ventilation can be made into the temperature of the said range. Further, at the time of depressurization, the mixture of the radiation curing medium and the natural rubber fine particle-containing aqueous emulsion can be heated to the above temperature range by a heating means such as a warm bath.

  From the viewpoint of obtaining an adhesive composition having excellent and uniform dispersion of natural rubber fine particles having a desired average particle size and high moisture content, the water content of the aqueous emulsion containing natural rubber fine particles is vaporized. At this time, it is preferable that the vaporized water is forcibly removed by blowing warm air or reducing the pressure in addition to the warm bath, and the replacement of the dispersion medium is completed in about 30 minutes to 5 hours. Instead of the warm bath, warm air can be blown to forcibly remove the water vaporized with heating.

  When a natural rubber rubber and a copolymer of at least one of an acrylic monomer and a styrene monomer are used as the natural rubber fine particles, the dispersion medium is replaced by mixing an aqueous emulsion and a radiation curable medium. Prior to this, a copolymer may be synthesized.

  Such a copolymer is obtained by adding at least one of an acrylic monomer and a styrene monomer to an aqueous emulsion containing natural rubber fine particles, and at least one of an acrylic monomer and a styrene monomer in the natural rubber emulsion. Can be synthesized by vinyl polymerization.

  In this case, for example, an organic peroxide-based initiator can be used as the polymerization initiator, and a redox-based initiator composed of an organic peroxide and ethylenediamine is preferable, among which t-butyl hydroperoxide (t-BHPO) and A redox initiator composed of tetraethylenepentamine (TEPA) is preferred. Further, as the organic peroxide, ketone peroxide, diacyl peroxide, dialkyl peroxide, peroxy ketal, peroxy ester, peroxy carbonate and the like are preferable, and ethylene diamines include ethylene diamine (EDA) and diethylene triamine (DETA). Tetraethylenetetraamine (TETA), pentaethylenehexamine (PEHA) and the like are preferable.

  Moreover, the usage-amount of a polymerization initiator can be made into the range of 0.01-10 mass parts with respect to 100 mass parts of natural rubber-type microparticles | fine-particles.

  Furthermore, as required, terpene resin, rosin, oil-soluble phenol resin, coumarone indene resin, petroleum hydrocarbon resin, terpene resin derivative, rosin derivative, oil-soluble phenol resin derivative, coumarone indene resin derivative It is also possible to add a tackifier such as a derivative of petroleum hydrocarbon resin to the copolymer.

  The emulsion immediately after the synthesis of the copolymer obtained as described above contains unreacted monomers and the like in addition to the copolymer. Such a copolymer may be purified, but without purification, the dispersion medium can be replaced by mixing a radiation-curable medium with the emulsion immediately after synthesis.

  After replacing the dispersion medium, a polymerization initiator for curing the radiation curable medium when forming the adhesive layer can be further added as necessary.

  In addition, styrene-butadiene rubber latex can be added to the natural rubber-based fine particles from the viewpoint of improving the adhesive strength of the obtained adhesive layer and the fixability of the adhesive layer to the base material. Styrene-butadiene rubber latex is considered to improve the adhesion between the substrate to which the adhesive composition is applied and the natural rubber-based fine particles.

  Styrene-butadiene rubber latex is mainly composed of styrene-butadiene rubber (SBR), and as SBR, emulsion polymerization SBR such as SBR driver and SBR latex; solution polymerization SBR such as random SBR, block SBR and symmetric block SBR is used. be able to.

  Further, the characteristics of SBR greatly depend on the copolymerization ratio of styrene and butadiene. From such a viewpoint, the styrene content is low (30% by mass or less), the styrene content is moderate (more than 30% by mass and 70% by mass or less), and the styrene content is high (over 70% by mass). ) And the like, and can be used in styrene-butadiene rubber latex.

  Examples of the SBR used as the main component of the styrene-butadiene rubber latex include a non-modified type, a vinylpyridine-modified type, and a carboxy-modified type. Among them, carboxy-modified styrene-butadiene rubber latex is preferable because it has excellent adhesion to the base sheet and can improve the adhesive force between the natural rubber fine particles and the base sheet.

  The mixing ratio of the natural rubber-based fine particles and the styrene-butadiene rubber latex is 1 part by mass or more of styrene-butadiene rubber latex with respect to 100 parts by mass of the natural rubber-based fine particles from the viewpoint of improving the adhesive force of the natural rubber-based fine particles. Preferably, 5 parts by mass or more is more preferable. On the other hand, in order not to impair other characteristics of the natural rubber-based fine particles, the amount is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and still more preferably 20 parts by mass or less.

  In addition, by setting the content of the styrene-butadiene rubber latex to an appropriate value, it is possible to realize excellent interaction between the obtained adhesive layer and the printing agent such as ink and toner. Can be realized. Furthermore, since the adhesive strength after pressure bonding the adhesive layer can be moderated, it is possible to suppress the peeling of the adhesive layer when it is unnecessary after the pressure bonding, and the adhesive layer can be easily used when desired after pressure bonding. Can be peeled off.

[Filler]
In the present invention, in order to realize the excellent blocking resistance of the resulting pressure-sensitive adhesive composition, the adhesive composition has no affinity for natural rubber-based fine particles, that is, between natural rubber fine particles and Add filler that does not cause chemical reaction. Since the surface of the adhesive layer (adhesion surface) is formed with the addition of the filler, it is considered that the adhesion surface is prevented from adhering to other surfaces prior to pressure bonding of the adhesion surface, and the blocking resistance is improved. .

  In addition, if an irregularity is formed on the surface (adhesive surface) of the adhesive layer by adding a filler, it is possible to suppress the adhesion force from adhering to each other after the adhesive surface is pressed and the adhesive force from increasing. it is conceivable that. As a result, when it is necessary to peel the adhesive surface after the adhesive surface is pressure-bonded, the adhesive surface can be easily peeled off.

  The width of the filler is preferably 0.1 μm or more, more preferably 0.5 μm or more, further preferably 1 μm or more, and preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less from the viewpoint of transferability in offset printing. It is preferable to use the fine particles. By using such a fine particle filler, the anti-blocking property of the adhesive layer becomes particularly excellent, because the surface of the adhesive layer is easily formed in an uneven shape.

  Furthermore, using such a particulate filler is suitable for forming an adhesive layer by applying the adhesive composition onto a substrate sheet by offset printing. In the offset printing method, the ink on the plate is temporarily transferred to a transfer body (such as a rubber cylinder), and the ink on the transfer body is printed on a printing material. In other words, there is an ink transfer process, for example, transfer between rollers when kneading ink, transfer from this roller to a plate cylinder, transfer from a plate cylinder to a transfer rubber cylinder, and a substrate such as paper from a rubber cylinder. The transfer is often repeated, such as transfer to the At this time, particles larger than the nip width between the rollers or the cylinder are not easily transferred. The presence of filler fine particles with a width of 0.1 μm or more in the adhesive layer exhibits an excellent effect of improving the blocking resistance of the filler, and the width is 15 μm or less, so that it is filled in the offset printing transfer process. The material is also transferred well, and as a result, the resulting adhesive layer can have excellent blocking resistance.

  The width of the fine particles means the distance when the fine particles are sandwiched between two surfaces parallel to each other and the distance between the two surfaces is minimized. The width of the fine particles is, for example, the diameter if the fine particles are spherical, and the thickness if the fine particles are flat.

  The material for the filler can be appropriately selected from materials having no affinity for natural rubber-based fine particles. For example, examples of the filler include a silica-based filler, a talc-based filler, and a silicon-based filler. That is, fine particles mainly containing silica, talc, or silicon (including fine particles made of silica, talc, or silicon) can be used as the filler. When it is necessary to prevent the transparency of the adhesive layer from being hindered, it is preferable that the filler has a regular particle shape. Examples of such materials include various silica-based fillers, various starch-based fillers, synthetic zeolite, microspherical (meth) acrylic resin, microspherical polyethylene, spherical alumina, glass powder, shirasu balloon, activated clay, titanium oxide. And zinc oxide. These fillers may be used alone or in combination of two or more.

  Silica is easily made into porous fine particles, and the porous silica-based filler absorbs silicon oil or the like used for cleaning the fixing device in a printer that prints information on an information carrying sheet. As a result, the quality of the image printed on the information carrying sheet is improved. From this viewpoint, it is preferable to use a silica-based filler.

  Talc can have slipperiness to reduce friction, and by increasing the slipperiness of the surface, even if the surfaces coated with adhesive face each other, the faces facing each other slip, making it resistant to blocking Can be improved. From this viewpoint, it is preferable to use a talc filler.

  Silicon powder is a spherical powder in which the surface of a spherical silicone rubber powder is coated with a silicone resin. Silicone itself is used as a release agent for labels and the like, so that the surfaces of adhesives face each other when present on the surface. However, blocking resistance can be improved by the presence of a portion where the adhesives do not stick to each other. From this viewpoint, it is preferable to use a silicon-based filler.

  5 mass parts or more are preferable with respect to 100 mass parts of radiation-curable compounds, and, as for content in the adhesive composition of a silica type filler, 10 mass parts or more are more preferable from a viewpoint of blocking resistance improvement. Moreover, from an adhesive viewpoint of an adhesive composition, 30 mass parts or less are preferable, and 20 mass parts or less are more preferable.

  The content of the talc-based filler in the adhesive composition is preferably 5 parts by mass or more and more preferably 10 parts by mass or more with respect to 100 parts by mass of the radiation curable compound from the viewpoint of improving blocking resistance. preferable. Moreover, 40 mass parts or less are preferable from an adhesive viewpoint of an adhesive composition, and 20 mass parts or less are more preferable.

  The content of the silicon-based filler in the adhesive composition is preferably 1 part by mass or more and more preferably 2 parts by mass or more with respect to 100 parts by mass of the radiation curable compound from the viewpoint of improving blocking resistance. preferable. Moreover, 10 mass parts or less are preferable from an adhesive viewpoint of an adhesive composition, and 8 mass parts or less are more preferable.

  In addition to the additives as described above, an ultraviolet absorber (ultraviolet absorber) may be added to the adhesive composition in order to improve ultraviolet resistance.

  Examples of such ultraviolet absorbers include salicylic acids such as phenyl salicylate, butylphenyl salicylate and octylphenyl salicylate; dihydroxybenzophenone, hydroxymethoxybenzophenone, hydroxyoctoxybenzophenone, hydroxydodecyloxybenzophenone, hydroxymethoxysulfobenzophenone and bis ( Benzophenones such as methoxyhydroxybenzoylphenyl) methane; (hydroxymethylphenyl) benzotriazole, (hydroxybutylphenyl) benzotriazole, (hydroxydibutylphenyl) benzotriazole, (hydroxybutylmethylphenyl) chlorobenzotriazole, (hydroxydibutylphenyl) Chlorobenzotriazole, (hydroxydi Can be exemplified hindered amine and the like; mil) benzotriazole and [hydroxy (tetrahydrophthalimide) methyl phenyl] benzotriazole such as benzotriazole; cyanoacrylates such as ethyl hexyl cyano-diphenyl acrylate and ethyl cyano diphenylacrylate.

  Antioxidants can also be added to the adhesive composition. Antioxidants include amines including aromatic secondary amines such as amine-ketones, diphenylamines, diaryl-P-phenylenediamines, and alkylaryl-P-phenylenediamines; monophenols, bisphenols And phenols containing hydroquinone; organic sulfur; phosphites; composites of these can be used, and among these, phenols are preferred because of less contamination and coloring.

  Furthermore, if necessary, an adhesive composition can be prepared by using a synthetic rubber emulsion in combination. Synthetic rubber emulsions include emulsions in which synthetic rubbers such as polyisoprene rubber, polybutadiene rubber, acrylonitrile-butadiene rubber, methyl methacrylate-butadiene rubber, chloroprene rubber, butyl rubber, polyurethane rubber, thiocol rubber and acrylic rubber are dispersed in an aqueous medium. It can be illustrated.

  Moreover, a pressure-sensitive adhesive composition can also be produced using a synthetic resin emulsion in combination. Examples of synthetic resin emulsions include polyvinyl acetate emulsions, vinyl acetate-ethylene copolymer emulsions, polyacrylate emulsions, and polyvinyl chloride emulsions. Among these synthetic resin emulsions, those having a glass transition temperature (Tg) of −30 to 20 ° C. are suitable.

  In addition, an emulsifier can be added to the adhesive composition in order to stabilize the dispersion of the natural rubber-based fine particles. As such an emulsifier, anionic or nonionic surfactants such as rosin soap, naphthalene sulfonate, fatty acid soap and alkylbenzene sulfonate can be used.

  Furthermore, a pH adjuster, a tackifier, a viscosity modifier, an anti-aging agent, a stabilizer, a colorant, and the like can be mixed in the adhesive composition as necessary.

  The adhesive composition obtained as described above was applied onto a substrate sheet by a known application means such as a gravure coater, flexo, air knife coater, wire bar and bar coater, offset printing machine, etc. Can be formed.

  Especially, offset printing can perform mass printing with high accuracy, and in this respect, it is preferable to form an adhesive layer on a substrate sheet by offset printing.

  Among offset printing, a printing method that does not use dampening water, particularly dry offset printing that uses a relief printing plate without dampening water, is preferable to lithographic offset printing that uses dampening water. This is because even if the adhesive composition has compatibility with water, printing can be performed with high accuracy.

  The base sheet has a sheet-like shape, and synthetic paper such as synthetic paper, polyethylene, polyethylene terephthalate, polypropylene, and vinyl chloride can be used in addition to ordinary paper. When these synthetic films are used, it is preferable to subject the surface of the base sheet to surface treatment such as mat treatment and corona treatment.

The amount of the adhesive composition applied to the base sheet surface is preferably 1 g / m ² or more, more preferably 3 g / m ² or more, in order to maintain the adhesiveness, peelability and transparency of the adhesive layer. 4g / m ² or more, and on the other hand, preferably 30 g / m ² or less, more preferably 20 g / m ^2, more preferably 7 g / m ² or less.

  The pressure-sensitive adhesive layer can be formed by applying the adhesive composition of the present invention to a substrate sheet, and irradiating the coating film with radiation such as ultraviolet rays, electron beams, X-rays, i-rays, and g-rays. An example of the cross-sectional structure of the information carrying sheet obtained as a result is shown in FIG. A pressure-sensitive adhesive layer is formed on the base sheet 42. The pressure-sensitive adhesive layer is a radiation-cured product 41 of a radiation-curable medium in which natural rubber-based fine particles 40 and a filler are dispersed. A sheet can be obtained. In addition, it is considered that a part of the radiation curable medium that is the dispersion medium is diffused in the substrate before curing, and by irradiation with radiation, a part 43 of the radiation curable medium is cured in the substrate, It is thought that it is reacting with the substrate. As a result, high adhesive strength between the adhesive layer and the substrate can be realized.

  In addition, the coating film is dried as necessary before curing, but drying also proceeds simultaneously during the curing process by irradiation of radiation, and since the dispersion medium is a radiation curable medium, drying can be completed in a short time. In some cases, a separate drying step is not required.

[Information carrying sheet]
Here, FIG. 3A shows an example of an information carrying sheet from which the adhesive layer can be peeled, and FIG. 4A shows an example of an information carrying sheet from which the adhesive layer cannot be peeled. .

  In the case of FIG. 3A, information 12 such as confidentiality and confidentiality is printed on the adhesive layer 10 as shown in FIG. Thereafter, as shown in FIG. 3C, the information carrying sheet is folded along the fold line 11 so that the adhesive layer 10 is superposed, and the adhesive layer 10 is pressure-bonded. Then, as shown in FIG. 3D, the adhesive layer 10 is peeled off and information 12 is read when necessary. In this case, the adhesive layer is required to be easily peeled off at a desired time after pressure bonding. The adhesive composition is coated on the entire surface.

  On the other hand, in the case of the information carrying sheet shown in FIG. 4A, as shown in FIG. 4B, information 22 such as confidentiality and confidentiality is printed at a position where the adhesive layer 20 is not formed. . Thereafter, as shown in FIG. 4C, the information carrying sheet is folded along the fold line 21 so that the adhesive layer 20 is superposed, and the adhesive layer 20 is pressure-bonded. As shown in FIG. 4D, the information 22 is read by cutting a predetermined position (for example, perforation 23) of the base sheet without peeling off the adhesive layer 20. In this case, it is required that the adhesive layer does not substantially peel after the pressure bonding. The adhesive composition is applied with a pattern.

  It should be noted that the adhesive layer can be made peelable or non-peelable by changing the mixing ratio of the constituent materials of the pressure-sensitive adhesive composition, the pressure bonding conditions, and the like.

  When the adhesive layer is peelable, necessary information can be printed and printed on the obtained adhesive layer. In addition to using a general printing machine as a printing method, an electrophotographic method and an inkjet method as a printing method can be employed. In the case of the inkjet method, the printing agent is ink, and in the case of the electrophotographic method, the printing agent is toner. Thereafter, ultraviolet rays can be irradiated to dry and / or fix the printing agent. Also, the printing agent may be heated to dry and / or fix.

  The information information carrying sheet described above can be bonded in the form of bi-fold, tri-fold, cut-over and various superpositions, and can be suitably used as a postcard having a facing surface, various forms, notices, various cards, etc. .

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not restrict | limited to a following example. Unless otherwise specified, commercially available high-purity products were used as reagents.

[Example 1]
For 100 parts by mass of radiation curable compound (polyethylene glycol diacrylate, trade name: Aronix M-240, manufactured by Toagosei Co., Ltd.), filler (silica fine particles, trade name: E200, manufactured by Tosoh Corporation, width: 2.9). -4.1) were dispersed in 16.7 parts by mass.

  A radiation curable compound in which the filler was dispersed was mixed with an aqueous emulsion of natural rubber fine particles (natural rubber latex, trade name: N646-A, manufactured by Etec, natural rubber fine particle content: 53 mass%). At this time, the mixing ratio was set so that the natural rubber fine particles in the obtained mixture would be 83.3 parts by mass with respect to 100 parts by mass of the radiation curable compound.

  The resulting mixture is stirred well and then heated with warm air at 80 ° C. while stirring further to vaporize the water and replace the dispersion medium of the natural rubber-based fine particles from water to a radiation curable compound. A dispersion in which a filler and natural rubber fine particles were dispersed in a functional compound was obtained. The water content of the dispersion was 0.5% by mass.

  To this dispersion, a polymerization initiator (trade name: BYCURE 55, manufactured by Akzo Nobel) was added and stirred well to obtain a pressure-sensitive adhesive composition. The polymerization initiator was used in an amount of 10 parts by mass with respect to 100 parts by mass of the radiation curable compound.

Using an RI tester (trade name: RI tester, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), the above pressure-sensitive adhesive composition is dry offset printed on coated paper (trade name: OK Coat Green, manufactured by Oji Paper Co., Ltd., 110 kg). The whole surface was coated. The coating amount was 3 g / m ² .

  The obtained coating layer was irradiated with ultraviolet rays using a high-pressure mercury lamp ozoneless (trade name: H04-L22, manufactured by Eye Graphics Co., Ltd.) to cure the adhesive composition to obtain an information carrying sheet. .

  The obtained information carrying sheet was evaluated for adhesive strength and tackiness. The results are shown in Table 1.

(1) Measurement of adhesive strength After overlapping the surfaces on which the adhesive layer of the information carrying sheet is formed, the width between the rollers using a sealing machine (trade name: Prestle Multi, manufactured by Toppan Forms) Was set to 200 μm for sealing. After sealing, using an autograph (trade name: AGS-50A, manufactured by Shimadzu Corporation), the peeling force was 300 mm / min, and the adhesive strength was measured by T-type peeling.

(2) Evaluation of tackiness Information-carrying sheets were cut out in 10 cm squares, sandwiched with clothespins, left to stand at 23 ° C. and a relative humidity of 50% for 1 hour, and then the clothespins were removed. The state at this time was visually observed and evaluated as follows.
X: The information carrying sheet (the surface on which the adhesive layer was formed) adhered to the clothespin, and the information carrying sheet was not immediately peeled off from the clothespin.
○: The information carrying sheet was slightly adhered to the clothespin, but peeled off immediately.
A: The clothespins were separated from the information carrying sheet very easily.

[Example 2]
A pressure-sensitive adhesive composition and an information carrying sheet were obtained and evaluated in the same manner as in Example 1 except that the silica fine particles were used in an amount of 8.35 parts by mass instead of 16.7 parts by mass with respect to 100 parts by mass of the radiation curable compound. Went. The results are shown in Table 1.

Example 3
Example except that talc (trade name: MS-P, manufactured by Nippon Talc Co., Ltd., width: 12 μm) was used as the filler instead of silica fine particles, and 20 parts by mass was used for 100 parts by mass of the radiation curable compound. In the same manner as in No. 1, a pressure-sensitive adhesive composition and an information carrying sheet were obtained and evaluated. The results are shown in Table 1.

Example 4
Implemented except that silicon powder (trade name: KMP605, manufactured by Shin-Etsu Chemical Co., Ltd., width: 2 μm) was used instead of silica fine particles as the filler, and 7.14 parts by mass was used for 100 parts by mass of the radiation curable compound. In the same manner as in Example 1, a pressure-sensitive adhesive composition and an information carrying sheet were obtained and evaluated. The results are shown in Table 1.

[Comparative Example 1]
A pressure-sensitive adhesive composition and an information carrying sheet were obtained and evaluated in the same manner as in Example 1 except that no filler was used. The results are shown in Table 1.

[Comparative Example 2]
A pressure-sensitive adhesive composition and an information carrying sheet were obtained and evaluated in the same manner as in Example 4 except that no filler was used. The results are shown in Table 1.

  The adhesive force should be about 30 gf / 25 mm (0.29 N / 25 mm) or more, and the adhesive force was good in all examples. The tackiness is also good in all examples, and such an information carrying sheet is excellent in blocking resistance. Further, the adhesive compositions of the examples could be satisfactorily applied to the substrate sheet by offset printing.

It is a schematic diagram explaining the preparation method of adhesive composition. It is a schematic diagram for demonstrating an adhesive bond layer. It is a schematic diagram for demonstrating the information carrying sheet in case an adhesive bond layer is peelable. It is a schematic diagram for demonstrating the information carrying sheet when an adhesive bond layer cannot be peeled.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Adhesive layer 11 Folding line 12 Information 20 Adhesive layer 21 Folding line 22 Information 23 Perforation 30 Natural rubber fine particle 31 Water-based emulsion 32 Radiation curable medium 33 Mixture 34 Hot bath 40 Natural rubber fine particle 41 Curing of radiation curable medium Layer 42 Base sheet 43 Hardened layer of radiation curable medium (part diffused to base sheet)

Claims (8)

Natural rubber-based fine particles, a radiation curable compound, and a non-affinity filler for the natural rubber-based fine particles,
The adhesive composition, wherein the filler is fine particles having a width of 0.1 μm or more and 15 μm or less.   The adhesive composition according to claim 1, which is for offset printing.   The adhesive composition according to claim 1, wherein the filler is at least one selected from the group consisting of a silica-based filler, a talc-based filler, and a silicon-based filler.   The said filler is a silica type filler, Comprising: The silica type filler is included in the ratio of 5 to 30 mass parts with respect to 100 mass parts of the said radiation curable compounds. The adhesive composition according to Item.   The said filler is a talc-type filler, Comprising: The talc-type filler is included in the ratio of 5 mass parts or more and 40 mass parts or less with respect to 100 mass parts of said radiation-curable compounds. The adhesive composition according to Item.   The said filler is a silicon-type filler, Comprising: The silicon-type filler is included in the ratio of 2 mass parts or more and 8 mass parts or less with respect to 100 mass parts of said radiation-curable compounds. The adhesive composition according to claim 1. A mixing step of mixing a radiation curable medium in which a filler is dispersed and a water-based emulsion containing natural rubber-based fine particles; and the water system while stirring the mixture obtained in the mixing step while blowing or under reduced pressure. Vaporizing and removing water contained in the emulsion, and having a medium replacement step of replacing the medium in which the natural rubber-based fine particles are dispersed with water from the radiation curable medium;
A method for producing an adhesive composition, wherein the filler is fine particles having a non-affinity with respect to the natural rubber-based fine particles and having a width of 0.1 μm or more and 15 μm or less. Having a pressure sensitive adhesive layer on the substrate sheet;
The pressure-sensitive adhesive layer is a cured product of an adhesive composition containing natural rubber fine particles, a radiation curable compound, and a filler,
The information-carrying sheet, wherein the filler is a fine particle having a non-affinity with respect to the natural rubber-based fine particles and having a width of 0.1 µm to 15 µm.

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