JP2014228782A - Heat seal label excellent in adhesive strength - Google Patents

Abstract

The present invention relates to a heat seal label which realizes good productivity by printing or coating a design printing layer and a thermal adhesive layer on a base material layer with a common printing machine, and also has good adhesiveness. The purpose is to provide. The present invention is a heat seal label in which a design printing layer is provided on one side of a base material layer, and a thermal adhesive layer formed by applying a thermal adhesive is laminated on the other side. The heat-seal label is characterized in that the thermal adhesive contains styrene / maleic resin (A).

Description

  The present invention relates to a heat seal label in which a thermal adhesive layer formed by applying a thermal adhesive to a base material layer is laminated. In particular, heat-seal labels used for pudding, yogurt, jelly, etc., for articles such as cups, bottles, cylinders, quadruple pot packs, and triple pot packs heat-sealed in synthetic resin containers Preferably used.

An adhesive label has been used as a label of a conventional synthetic resin container. Adhesive labels are mainly used in shampoo containers, etc., but after applying an adhesive to the label, affixing a release paper (separator) is applied to a synthetic resin container while removing the release paper when applying the label. There is a way to attach it.

However, the pressure-sensitive adhesive label is expensive due to the release paper. Under such circumstances, thermal labels coated with a delayed tack adhesive have been put into practical use for several years. A delayed tack adhesive is an adhesive that has been applied to a label paper and dried, and is not sticky at room temperature. It will last. Most of the bonding methods use a thermal labeler. As a thermal labeler, there is a method in which hot air of several hundred degrees Celsius is blown onto the surface of the label where the delayed tack is applied, the tack is developed on the surface, and the label is attached to a bottle or a plastic bottle.

  However, this delayed tack label is blocked when it reaches 40 ° C. or higher during storage and transportation, because tack appears. It also has many problems in terms of slipperiness and cutting properties that are suitable for high-speed labeling machines. Therefore, a heat-sensitive label having a hot-melt adhesive (not sticky at room temperature) layer that is not a hot-melt adhesive is also being put into practical use. Hot-melt adhesive is not sticky at room temperature, and a heat-sensitive label coated with hot-melt adhesive is affixed to an adherend while heating, so that no release paper is required and the adhesive has a wax. Therefore, it does not block during normal transportation and handling.

  In addition, such a hot melt adhesive does not have fluidity at normal temperature, and it is necessary to perform coating while heating the adhesive itself to provide fluidity. Has the disadvantage that it is expensive and results in poor productivity.

  In addition, the surface of the base material layer of such a label may be printed with the image of a product, a product name, a barcode, a manufacturer, etc. by a printing machine such as gravure printing, flexographic printing, silk screen printing, etc. However, productivity is inferior because it is necessary to apply the pressure-sensitive adhesive or adhesive on the back surface of the base material layer with another coating machine.

  In addition, for example, a four-pot pack label for yogurt has a printed design layer on one side of the base material layer, and a polyethylene resin and a hot melt adhesive are applied on the other side. In order to prevent the label from being peeled off due to its design, light-shielding properties, long-distance distribution, etc. In addition, there is a demand for complete adhesion to a synthetic resin container.

  Such a four-pot pot pack for yogurt is generally attached with a label by an in-mold sticking method.

  With the in-mold sticking method, a label cut into a desired shape is inserted into a container-forming mold, and a thermoplastic resin is injection-molded to form a container body and a resin container with a lid covered with the label. Or by inserting a label into the differential pressure molding die and introducing a melted polystyrene resin sheet onto the die to form plug-assisted vacuum molding and / or pressure forming to attach the label. I have a container. However, in this method, labels must be supplied one by one in the mold, resulting in poor productivity.

JP 2000-142650 A Japanese Patent Laid-Open No. 11-296088

    The present invention provides a heat seal label which realizes good productivity by printing or coating a design printing layer and a thermal adhesive layer on a base material layer with a common printing machine, and which has good adhesiveness. For the purpose.

That is, a heat seal label having a design printing layer on one side of a base material layer and a thermal adhesive layer formed by applying a thermal adhesive on the other side, The present invention relates to a heat seal label comprising a styrene / maleic resin (A).

The present invention also relates to a heat seal label, wherein the thermal adhesive further contains an acrylic resin (B) other than the acrylic / polyester / polyolefin graft polymer dispersion.

The present invention also relates to a heat seal label, wherein the thermal adhesive further contains an acrylic / polyester / polyolefin graft polymer dispersion (C).

The present invention also relates to a heat seal label, wherein the thermal adhesive further contains a polyester resin (D).

Moreover, the heat seal label which laminated | stacked the heat adhesive layer which has a design printing layer on one side of a base material layer, and apply | coating the heat adhesive on the other side, Comprising: (1) , (2).
(1) Thermal adhesives are styrene / maleic resin (A), acrylic resin (B) other than acrylic / polyester / polyolefin graft polymer dispersion, acrylic / polyester / polyolefin graft polymer dispersion (C) and polyester resin (D ).
(2) 20 to 45 parts by weight of styrene / maleic acid resin (A), 15 to 30 parts by weight of acrylic resin (B), 100 / part by weight of solid content of thermal adhesive, acrylic / polyester / polyolefin graft polymer dispersion ( C) is 15 to 30 parts by weight, and the polyester resin (D) is 15 to 30 parts by weight.

In addition, the present invention is a method in which one end portion of the thermal adhesive layer of the heat seal label is heat bonded to a synthetic resin container, and then the heat seal label is wrapped around the outer periphery of the synthetic resin container. The present invention relates to a package that is thermally bonded so that both ends of the label overlap.

  A heat-seal label in which a heat-adhesive layer formed by applying a heat-adhesive is laminated, wherein the heat-adhesive contains a styrene / maleic resin (A). There is no need to heat the thermal adhesive when working, and the adhesive strength to the synthetic resin container and the base material layer can be maintained.

  Furthermore, the heat seal label of the present invention can improve productivity because the design printing layer and the thermal adhesive layer can be printed or coated on the base material layer using a common printer.

The heat seal label 1 is provided with a thermal adhesive layer 3 on one surface of a base material layer 2 and a design printing layer 4 on the other surface. One end of the thermal adhesive layer of the heat seal label 1 is heat bonded to the synthetic resin container, and then the heat seal label is wrapped around the outer periphery of the synthetic resin container, so that both ends of the heat seal label are wrapped. Are heat-bonded at the overlapping part.

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the heat seal label 1 is provided with a thermal adhesive layer 3 on one surface of a base material layer 2 and a design printing layer 4 on the other surface.

  As the base material layer 2, plastics such as paper, synthetic paper, vapor-deposited paper, PRT (polyethylene terephthalate phthalate), polyester, polypropylene, polyethylene, nylon, vinyl chloride, cellophane, and composite papers thereof are used. From the viewpoints of moldability, flexibility, and film strength, the thickness is about 6 to 100 μm, preferably 9 to 50 μm.

For example, if the base material layer is paper, synthetic paper, vapor-deposited paper, etc., the Eco Design F series (both manufactured by Toyo Ink Co., Ltd.) can be used for the print design layer 4, and the fine star series can be used for synthetic resin films. (Both manufactured by Toyo Ink Co., Ltd.) can be used, and the thickness of the print design layer 4 is not particularly limited, but is about 0.1 μm to 5 μm.

  The print design layer 4 can be printed by a known printing method such as gravure printing, flexographic printing, inkjet printing, offset printing, silk screen printing, or the like. Gravure printing, silk screen printing or flexographic printing which can be laminated with a thermal adhesive layer is preferable.

  For the thermal adhesive layer 3, various printing methods such as gravure printing, flexographic printing, silk screen printing, etc. for styrene / maleic resin (A), roll coater method using direct rolls and gravure rolls, and extrusion are used. Printing can be performed by a coater method or a slit orifice coater method. In particular, it is preferable to perform lamination by gravure printing, flexographic printing, and silk screen printing on which a design printing layer can be laminated. By using these printing methods, the design printing layer and the thermal adhesive layer can be laminated simultaneously, which is preferable in terms of productivity and cost.

The application amount of the thermal adhesive is preferably 1.5 to 15 g / m ² from the viewpoints of adhesiveness, workability, and economy.

  The styrene / maleic acid resin (A) is a resin obtained by copolymerizing styrene and maleic anhydride by a known method. Alternatively, it can be obtained by emulsion polymerization in the presence of a surfactant.

  The styrene / maleic acid resin (A) is used for improving the adhesive strength by strong chemical interaction with the synthetic resin container. In addition, since the bond constituting the skeleton is strong, the compound is hardly deteriorated or hardly deteriorated with time. In addition, it is suitable for various printing and coating methods because it dissolves in common solvents. Specifically, the styrene / maleic acid resin preferably has a weight average molecular weight of 2000 to 50000 from the viewpoint of adhesive strength and solubility. Moreover, it is preferable that the glass transition temperature is 40 degreeC to 200 degreeC from the point of workability | operativity of the adhesion temperature at the time of heat-sealing a heat seal label to the opening part of a synthetic resin container. The acid value is preferably 20 to 450 from the viewpoint of solubility. In addition, from a viewpoint of adhesion | attachment to a synthetic resin container, it is preferable that a styrene / maleic acid resin (A) is 15-30 weight part in 100 weight part of thermal adhesives.

  Further, the styrene / maleic acid resin (A) can be partially copolymerized with other monomers. Furthermore, it may be partially modified with a hydroxyl group-containing compound or an amino group-containing compound.

  The hydroxyl group-containing compound or amino group-containing compound is not particularly limited as long as it contains a hydroxyl group or an amino group in the molecule. Examples of the hydroxyl group-containing compound include ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n -Propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, ethylene glycol mono 2-ethylhexyl ether, ethylene glycol monoallyl ether, ethylene glycol monophenyl ether, ethylene Glycol monobenzyl ether, diethylene glycol, diethylene glycol Methyl ether, diethylene glycol monoethyl ether, diethylene glycol mono n-propyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol mono 2-ethylhexyl ether, diethylene glycol monobenzyl ether, triethylene Glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol mono n-butyl ether, tetraethylene glycol, tetraethylene glycol monomethyl, tetraethylene glycol monoethyl, tetraethylene glycol mono n-butyl, pro Len glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-propyl ether, propylene glycol monoisopropyl ether, propylene glycol mono n-butyl ether, propylene glycol monophenyl ether, dipropylene glycol, dipropylene glycol monomethyl ether , Dipropylene glycol monoethyl ether, dipropylene glycol mono n-propyl ether, dipropylene glycol mono n-butyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol mono n-butyl ether, 1,3-butanediol, 1, 4-butanediol, 3-methyl-1,3-butanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 3-methoxy-3-methyl-1-butanol, 2 -Ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, glycerin, diglycerin, acetylenic diol, diacetone alcohol and the like.

   Examples of the amino group-containing compound include monoethanolamine, N-methylmonoethanolamine, N, N-dimethylmonoethanolamine, N, N-diethylmonoethanolamine, 2- (2-aminoethoxy) ethanol, 2- (2 -Aminoethylamino) ethanol, 2-amino-1-butanol, 4-amino-1-butanol, diethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, triethanolamine, N- (3-aminopropyl) diethanolamine and the like. Can be mentioned.

  The thermal adhesive that can be used for the thermal adhesive layer 3 can be produced by dissolving the styrene / maleic resin (A) in an organic solvent by a known method.

  Solvents used for the styrene / maleic acid resin (A) include ester solvents such as ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, propylene glycol monoethyl ether acetate, methanol, ethanol, n-propanol, Alcohol solvents such as isopropanol and n-butanol, aromatic solvents such as benzene, toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and known solvents such as water can be used alone or in combination.

  In addition to the styrene / maleic acid resin (A), various resins can be used in combination with the thermal adhesive layer 3 depending on the application, base material, and required physical properties.

  Examples include acrylic resins (B) other than acrylic / polyester / polyolefin graft polymer dispersions, acrylic / polyester / polyolefin graft polymer dispersions (C), and polyester resins (D). These resins can be used alone or in admixture of two or more.

  Furthermore, 20 to 45 parts by weight of styrene / maleic acid resin (A), 15 to 30 parts by weight of acrylic resin (B), acrylic / polyester / polyolefin graft polymer dispersion (C ) Is preferably 15 to 30 parts by weight, and the polyester resin (D) is preferably 15 to 30 parts by weight.

  The acrylic resin (B) is used for improving the adhesive strength. The acrylic resin has a strong cohesive force and can maintain the adhesive strength at the normal temperature. In addition, it is easy to adopt because of its low cost. A well-known thing can be employ | adopted for an acrylic resin (B). The weight average molecular weight is preferably 20,000 to 300,000 from the viewpoint of solubility in a solvent and cohesive strength of the resin. Moreover, it is preferable that the glass transition temperature is 10 ° C. to 200 ° C. from the viewpoint of securing the hot adhesive strength. The acid value is preferably from 0 to 100 from the viewpoint of the handleability of the ink. Specifically, acrylic-modified urethane, blend resin of acrylic (methacrylic acid) and vinyl butyral, polyacrylic acid ester, polymethacrylic acid ester, polymethyl methacrylate, ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer From ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ionomer and the like. Can be used, and two types of resins may be used in combination. From the viewpoint of the cohesive strength of the resin, the acrylic resin (B) is preferably 15 to 30 parts by weight in 100 parts by weight of the thermal adhesive.

  Other resins that can be used in combination include resins having a styrene component. Specifically, styrene-ethylene / butylene-styrene block polymer (SEBS), styrene / butadiene block copolymer (SB: diblock), (SBS: triblock), styrene / isoprene block Polymer (SI: diblock), (SIS: triblock) or styrene / butadiene-isoprene block copolymer (SB / I: diblock), (SB / IB) : Triblock), hydrogenated products thereof (for example, hydrogenated product of styrene / butadiene / styrene block copolymer (SBS), hydrogenated product of styrene / isoprene / styrene block copolymer (SEPS)), or These carboxylic acid modified products are exemplified. A part of styrene constituting the styrene block may be replaced with an aromatic vinyl compound such as α-methylstyrene. Other examples include styrene / acrylic copolymers and styrene / resin copolymers, styrene / rubber copolymer resins, and modified resins thereof. These resins may be used alone or in combination of two or more, and the content thereof is preferably 15 to 30% by weight with respect to the total weight of the thermal adhesive.

  The acrylic / polyester / polyolefin graft polymer dispersion (C) has particularly strong cohesive strength of the acrylic resin component, and can maintain adhesive strength at room temperature. In addition, since the grafted polyester resin and polyolefin resin component are firmly bonded to the base material layer, it is possible to further improve the adhesive strength at normal temperature. As the acrylic / polyester / polyolefin graft polymer dispersion (C), known ones can be adopted, and specifically, the weight average molecular weight is preferably 20,000 to 200,000 from the viewpoint of securing the cohesive strength of the resin. In addition, from the viewpoint of the cohesive strength of the resin and adhesion to the substrate, the acrylic / polyester / polyolefin graft polymer dispersion (C) is preferably 15 to 30 parts by weight in 100 parts by weight of the thermal adhesive.

  The acrylic / polyester / polyolefin graft polymer dispersion (C) is generally produced by grafting a monomer that produces an acrylic polymer to the polyester polymer and polyolefin polymer under suitable reaction conditions. This acrylic / polyester / polyolefin graft polymer dispersion (C) is a graft polymer having a polyester chain, a polyolefin chain, and a poly (meth) acrylate chain.

  The acrylic / polyester / polyolefin graft polymer dispersion (C) described above is prepared in a suitable solvent inert to the polymerization conditions and having a boiling point above the normal synthesis temperature. Solvents include, for example, acetate esters such as ethyl acetate, propyl acetate or butyl acetate, aliphatic solvents such as isooctane, cycloaliphatic solvents such as cyclohexane and carbonyl solvents such as butanone.

  The acrylic / polyester / polyolefin graft polymer dispersion (C) is produced by mixing a monomer in which a monomer for forming an acrylic polymer is added in a solvent in which the polyester polymer and / or polyolefin polymer described below is dissolved. It can be obtained by polymerization at a temperature of −10 ° C. to 100 ° C. within 4 to 8 hours under the addition of one or several peroxide radical initiators. For example, peresters such as tert-butyl peroctoate are used as radical initiators. This initiator concentration is generally 0.1% to 3% by weight based on the monomer.

  As a component for forming the polyester polymer used when the acrylic / polyester / polyolefin graft polymer dispersion (C) is produced, a polyester polymer whose monomer structural unit is characteristic of itaconic acid is used. This polyester polymer has a linear or branched structure and has an OH value of -5 to 150 mg KOH / g, preferably 10 to 50 mg KOH / g, preferably 5 mg KOH / g or less, more preferably 2 mg KOH / g or less. It is characterized by an acid number of 700 to 25000 g / mol, preferably a number average molecular weight of 2000 to 12000 g / mol.

  The content of itaconic acid in the polyester polymer is in the range of 0.1 mol% to 20 mol%, preferably 1 mol% to 10 mol%, more preferably 2 mol% to 8 mol%, based on the total amount of polycarboxylic acid used. Is in. Otherwise, the type of polycarboxylic acid used for the polyester polymer according to the invention is arbitrary per se. Aliphatic and / or cycloaliphatic and / or aromatic carboxylic acids can be included. A polycarboxylic acid is preferably a compound having one or more, more preferably two or more carboxyl groups and, unlike the general definition, is also a monocarboxylic acid in a special embodiment.

Examples of the aliphatic polycarboxylic acid having a short chain are succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, and octadecanedioic acid. An example of a cycloaliphatic polycarboxylic acid is an isomer of cyclohexanedicarboxylic acid. Examples of aromatic polycarboxylic acids are isomers of benzenedicarboxylic acid and trimellitic acid. If appropriate, instead of the free polycarboxylic acids, it is also possible to use their esterifiable derivatives, for example the corresponding lower alkyl esters or cyclic anhydrides. The type of polyol used for the polyester polymer is arbitrary. Aliphatic and / or cycloaliphatic and / or aromatic polyols can be included. A polyol is preferably a compound having one or more, more preferably two or more hydroxyl groups and, unlike the general definition, is also a monohydroxy compound in a particular embodiment.

Examples of polyols are ethylene glycol, propanediol-1,2, propanediol-1,3, butanediol-1,4, pentanediol-1,5, hexanediol-1,6, nonanediol-1,9, Dodecanediol-1,12, neopentyl glycol, butylethylpropanediol-1,3, methylpropanediol-1,3, methylpentanediol, cyclohexanedimethanol, trimethylolpropane, pentaerythrol and mixtures thereof.

An aromatic polyol is a reaction product of an aromatic polyhydroxy compound such as hydroquinone, bisphenol A, bisphenol F, dihydroxynaphthalene and the like and an epoxide such as ethylene oxide or propylene oxide. Polyols can also include ether diols, ie oligomers or polymers based on, for example, ethylene glycol, propylene glycol or butanediol 1,4. In particular, a linear aliphatic glycol is preferable.

In addition to polyols and dicarboxylic acids, lactones can also be used.

The polyester polymer having an itaconic acid content of 0.1 mol% to 20 mol%, preferably 1 mol% to 10 mol%, more preferably 2 mol% to 8 mol%, based on the total amount of polycarboxylic acid used is (heavy) Manufactured with techniques established for condensation reactions.

In each pre-reaction mixture for preparing the acrylic / polyester / polyolefin graft polymer dispersion (C), the amount of polyester polymer used before the grafting reaction is 10% to 90% by weight, preferably 25%. It is 40% by mass to 60% by mass, particularly preferably 40% by mass to 75% by mass.

Standard methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate and isobutyl methacrylate as examples of monomers for forming acrylic polymers that can be used in acrylic / polyester / polyolefin graft polymer dispersions (C) In addition, acrylic acid or methacrylic acid can be used. Among acrylic polymers, styrene, α-methylstyrene, vinyl chloride, vinyl acetate, vinyl stearate, vinyl methyl ketone, vinyl isobutyl ether, allyl acetate, allyl chloride, allyl isobutyl ether, allyl methyl ketone, maleic acid Dibutyl, dilauryl maleate, dibutyl itaconate may be contained.

The amount of monomer that forms the acrylic polymer used in each pre-reaction mixture for preparing the acrylic / polyester / polyolefin graft polymer dispersion (C) is 10% to 90%, preferably 25%. % To 75% by mass, more preferably 40% to 60% by mass.

  The polyolefin polymers to be used are known per se. This is primarily a polymer composed of ethylene-, propylene-, butylene- and / or other α-olefins having 5-20 C atoms, which is already recommended as a sealable material. ing. This molecular weight is generally 10,000 to 300,000, preferably 50,000 to 150,000. The types of olefin copolymers to be applied are described, for example, in DE-OS1644941, DE-OS1769834, DE-OS1939037, DE-OS1963039 and DE-OS2059981 in German Patent Publications.

For example, Buna® 6170 (manufacturer: Lanxess AG) can be used as the polyolefin polymer.

Ethylene-propylene-copolymers can be used with particular advantage; terpolymers with the addition of known third components such as ethylidene-norbornene (see Macromolecular Reviews, Vol. 101975) are also possible, however, This must take into account the tendency to crosslink during the aging process. This distribution can in this case be sufficiently statistical, but it is also possible to use sequence polymers with advantageously ethylene blocks. The proportion of monomeric ethylene-propylene is in this case variable within a predetermined range, which can be delimited by about 95% for ethylene and about 95% for propylene as upper limits.

The amount of the polyolefin polymer used for producing the acrylic / polyester / polyolefin graft polymer dispersion (C) in the present invention is 5% by mass to 60% by mass, preferably 20% by mass to 55% by mass, particularly preferably 25%. Mass% to 55 mass%.

  The polyester resin (D) is used for improving the adhesive strength due to strong chemical interaction with the base material layer. As the polyester resin (D), known ones can be adopted. Specifically, the polyester resin (D) preferably has a weight average molecular weight of 1,000 to 100,000 from the viewpoint of securing the cohesive strength of the resin. Moreover, it is preferable that a glass transition temperature is -10 degreeC to 200 degreeC from the point of ensuring of the adhesive strength in hot. In addition, it is preferable that a polyester resin (D) is 15-30 weight part in 100 weight part of thermal adhesives from an adhesive point with a base material layer.

Examples of the polyvalent carboxylic acid component of the polyester resin (D) in the present invention include aromatic dicarboxylic acids such as itaconic acid, terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, succinic acid, glutaric acid, adipic acid, Aliphatic dicarboxylic acids such as azelaic acid, sebacic acid, dodecanedioic acid and dimer acid, unsaturated dicarboxylic acids such as (anhydrous) maleic acid, fumaric acid and terpene-maleic acid adducts, 1,4-cyclohexanedicarboxylic acid, tetrahydro Alicyclic dicarboxylic acids such as phthalic acid, hexahydroisophthalic acid, 1,2-cyclohexene dicarboxylic acid, trivalent or higher carboxylic acids such as (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, methylcyclohexenticarboxylic acid, etc. Select one or more from these And it can be used.

 In particular, the group consisting of itaconic acid, isophthalic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 5-sodium sulfoisophthalic acid, dimer acid, hydrogenated dimer acid, 2,6-naphthalenedicarboxylic acid and fumaric acid It is preferable that it is at least 1 or more types of monomer chosen more.

 Examples of the polyhydric alcohol component used in the polyester resin (D) in the present invention include ethylene glycol, propylene glycol (1,2-propanediol), 1,3-propanediol, 1,4-butanediol, 1,2 -Butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol 2-ethyl-2-butyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1-methyl-1,8-octanediol, 3-methyl-1,6-hexanediol 4-methyl-1,7-heptanediol, 4-methyl-1,8-octanediol, 4-propyl-1,8-o Aliphatic glycols such as tandiol, 1,9-nonanediol, ether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedi Examples include alicyclic polyalcohols such as methanol, 1,2-cyclohexanedimethanol, tricyclodecane glycols, and hydrogenated bisphenols, and trihydric or higher polyalcohols such as trimethylolpropane, trimethylolethane, and pentaerythritol. One or more of these can be selected and used.

In particular, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol, polytetramethylene glycol, ethylene oxide adduct of bisphenol A, 1,2-propylene oxide adduct of bisphenol A, 1,6- Hexanediol, 2-methyl-1,3-propanediol, 1,2-propylene glycol, 1,3-propanediol, azelaic acid, dimer diol, hydrogenated dimer diol, polyethylene glycol, 2,2-dimethyl-3- Hydroxypropyl-2 ′, 2′-dimethyl-3-hydroxypropanoate, 1,5-pentanediol, diethylene glycol, triethylene glycol, 2-butyl-2-ethyl-1,3-propanediol, 3 (4), 8 (9) -Tricyclo [5.2.1 It is preferably .0 ^2.6] decanedimethanol.

 The polyester resin (D) of the present invention comprises a direct polymerization method in which a dicarboxylic acid and a glycol are directly esterified and polymerized at normal pressure or under pressure, a transesterification method in which a dimethyl ester of a dicarboxylic acid and a glycol are transesterified, and a polymerization is performed. It is synthesized by a known method such as a method of adding a small amount of xylene and performing a dehydration reaction at normal pressure. The charging ratio of the dicarboxylic acid component and the glycol component is not particularly limited, but is preferably in the range of glycol / dicarboxylic acid = 0.8 to 10 (molar ratio). Usually, it is preferably performed at around 2.

 The polyester resin (D) used in the present invention may be modified using various chemical reactions. That is, vinyl modification with a vinyl polymerizable monomer, epoxy resin modification with an epoxy compound, urethane modification with an isocyanate compound, lactone modification, polyemulsification acid modification, or acid depth modification may be performed. In the case of vinyl modification, an unsaturated double bond is introduced into the polyester resin by copolymerizing a dicarboxylic acid having an unsaturated double bond such as fumaric acid or oleic acid with the polyester resin. A method of radical polymerization of vinyl compounds such as (meth) arlylic acid ester, styrene and vinyl acetate in solution, or a macromonomer containing two hydroxyl groups directly at one end synthesized from (meth) arlylic acid ester and styrene. It is synthesized by a known method such as copolymerization with polyester.

 Epoxy resin modification is done by adding terminal anhydride groups such as trimellitic anhydride and phthalic anhydride to the terminal hydroxy group of the polyester resin to modify the terminal carboxyl, and then converting the carboxyl group and epoxy resin to a catalyst such as triphenylphosphine. It can be synthesized by a known method such as a method of performing epoxy modification in the presence of. In addition, a carboxyl group may be introduced by using a carboxyl group-containing glycol such as dimethylolpropionic acid as a chain extender.

 In the case of urethane modification, it is synthesized by a known method such as blending a low molecular weight polyester diol and, if necessary, a chain extender and reacting with a diisocyanate compound. Further, a carboxyl group may be introduced into the side chain using a carboxyl group-containing diol such as dimethylolpropionic acid as a chain extender.

 Examples of the lactone modification reaction include a ring-opening addition reaction of a lactone monomer to a polyester resin. This makes it possible to produce a block type polyester resin in which polycaprolactone is bonded to the end of the polyester resin. As a monomer to be used, ε-caprolactone is preferable. The reaction is preferably carried out in the range of 150 to 290 ° C. over a period of 1 to 300 minutes.

 An example of the polylactic acid modification reaction is a ring-opening addition reaction of a lactide monomer of a polyester resin. This makes it possible to produce a block type polyester resin in which polylactic acid is bonded to the end of the polyester resin. As the monomer to be used, any of L-lactide, DL-lactide, and D-lactide can be used. The reaction is preferably carried out in the range of 150 to 290 ° C. over a period of 1 to 300 minutes.

 Examples of the acid addition modification reaction include addition reaction of a carboxylic anhydride to a polyester resin. By this method, a carboxyl group can be efficiently introduced into the end of the polyester molecule. As auxiliary materials to be used, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-pentanetetracarboxylic dianhydride 3,4,3 ′, 4′-benzophenonetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5 , 6-Naphthalenetetracarboxylic dianhydride, ethylene glycol bistrimellitic dianhydride, 2,3,2 ′, 3′-diphenyltetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic Acid dianhydride, ethylenetetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl- - There is cyclohexene-1,2-dicarboxylic anhydride, etc., one among these, or select two or more can be used. Among these, phthalic anhydride, trimellitic anhydride, and ethylene glycol bistrimellitic dianhydride are preferable from the viewpoint of controlling the reaction and efficiently introducing a carboxyl group into the molecule. The reaction is preferably carried out in the range of 150 to 290 ° C. over a period of 1 to 300 minutes.

Moreover, the polyester polymer used when manufacturing an acrylic / polyester / polyolefin graft polymer dispersion (C) can also be used as a polyester resin (D).

The shape of the synthetic resin container used for the package heat-bonded using the heat seal label is a cup type, bottle type, pack type, cylindrical type, tube type, tray type, or quadruple pot pack synthetic resin container. Etc. As a material used for the synthetic resin container, for example, polystyrene, polypropylene, PET, or the like is preferably used. In addition, it is preferable to use properly the thermal adhesive layer 3 suitable for it according to the material of each resin container, and it is preferable to use the said styrene / maleic acid resin as the thermal adhesive layer 3 with respect to the container made from polystyrene. In particular, it is suitable for a barrel wound label of a quadruple pot pack used for yogurt or the like.

  Although various methods can be considered as a method for attaching the heat seal label, the following can be exemplified as typical methods, and any method may be used.

  1) One of the heat adhesive labels of the heat seal label is heat bonded to the synthetic resin container, and then the heat seal label is wrapped around the outer periphery of the synthetic resin container so that both ends of the heat seal label overlap. A method of attaching a heat seal label to a synthetic resin container by thermally bonding and pasting.

Although the heat bonding conditions depend on the type and thickness of the resin, a heat roll or a hot plate is generally used, and is usually about 0.3 to 5 seconds at 100 to 240 ° C.

  2) Whether the heat-sealed label cut into a desired shape is inserted into a container-forming mold, and a thermoplastic resin is injection-molded to form a container body and a resin container in which the lid is covered with the label. Alternatively, heat sealing can be performed by inserting a label into the differential pressure molding die, introducing a molten polystyrene resin sheet onto the die, plug-assisted vacuum molding and / or pressure forming, and applying a heat seal label A method of attaching a label to a synthetic resin container.

  3) A method in which hot air, infrared rays, or the like is applied to the heat adhesive layer of the heat seal label to activate the heat adhesive, and then attached to a synthetic resin container.

The conditions of hot air and infrared rays are about 0.5 to 20 seconds at 100 ° C. to 240 ° C., depending on the type and thickness of the resin.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples. In the present invention, “parts” and “%” represent “parts by weight” and “% by weight” unless otherwise noted.

<Number average molecular weight (Mn), weight average molecular weight (Mw)>
The measurement of v number average molecular weight (Mn) and weight average molecular weight (Mw) used GPC (gel permeation chromatography) "ShodexGPC System-21" by Showa Denko KK. GPC is liquid chromatography that separates and quantifies substances dissolved in a solvent based on the difference in molecular size. Tetrohydrofuran is used as a solvent, and weight average molecular weight (Mn) is determined in terms of polystyrene.

<Hydroxyl value (OHV)>
About 1 g of a sample is accurately weighed in a stoppered Erlenmeyer flask and dissolved by adding 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution. Further, exactly 5 ml of an acetylating agent (a solution in which 25 g of acetic anhydride was dissolved in pyridine to make a volume of 100 ml) was added and stirred for about 1 hour. To this, phenolphthalein reagent is added as an indicator and lasts for 30 seconds. Thereafter, the solution is titrated with a 0.1N alcoholic potassium hydroxide solution until the solution becomes light red.
The hydroxyl value was determined by the following formula. The hydroxyl value was a numerical value in the dry state of the resin (unit: mgKOH / g).
Hydroxyl value (mgKOH / g) = [{(ba) × F × 28.25} / S] / (Non-volatile content concentration / 100) + D
Where S: Amount of sample collected (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
b: Consumption of 0.1N alcoholic potassium hydroxide solution in the empty experiment (ml)
F: Potency of 0.1N alcoholic potassium hydroxide solution
D: Acid value (mgKOH / g)

<Acid value (AV)>
About 1 g of sample compound (B) was accurately weighed in a stoppered Erlenmeyer flask, and dissolved by adding 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution. To this was added a phenolphthalein test solution as an indicator, which was held for 30 seconds, and then titrated with a 0.1N alcoholic potassium hydroxide solution until the solution turned light red.
The acid value (mgKOH / g) was determined by the following equation as the value of the resin in the dry state.
Acid value (mgKOH / g) = {(5.611 × a × F) / S} / (Nonvolatile content concentration / 100)
Where S: Amount of sample collected (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Potency of 0.1N alcoholic potassium hydroxide solution

<Printing ink 1>
・ Fine Star R651AT White (manufactured by Toyo Ink Co., Ltd.)

<Styrene / maleic resin (A)>
-As styrene / maleic acid resin 1, X-205 (made by Seiko PMC Co., Ltd.) was used.
-SAA-100 (manufactured by Lyondell Chemical Co.) was used as the styrene / maleic resin 2.

<Acrylic resin (B)>
・ DEGALAN P24 (Evonik Industries AG)

(Synthesis example of graft polymer dispersion (C))
In a stirred tank, 42.9 g of EPDM (polyolefin polymer with ethylene-propylene-diene-rubber, Buna EP6170) and 20 g of the polyester polymer are placed at 90 ° C. in a mixture of 50 g of propyl acetate, 20 g of ethyl acetate and 10 g of isooctane. Disperse. To this mixture is first added 2 g of tert-butyl perbenzoate, followed by a mixture of 18.5 g of n-butyl methacrylate and 18.5 g of methyl methacrylate over a period of 90 minutes. The polymerization is subsequently carried out at 90 ° C. over a period of 120 minutes. Subsequently, 0.5 g of tert-butyl perbenzoate is added for the subsequent start and further stirred at 90 ° C. for 90 minutes.

For the copolymer dispersion, the polymer proportion is about 45% by weight and the solvent proportion is about 55% by weight.

 After a total reaction time of 150 minutes, the polymer solution was cooled and diluted with 13.5 g of propyl acetate to reduce the concentration of the solution to obtain graft polymer dispersion 3.

The graft polymer dispersion 3 is mainly composed of an acrylic / polyester / polyolefin graft polymer dispersion, and includes other binary copolymers and homopolymerized acrylic polymers.

<Polyester resin (D)>
・ Byron 300 (manufactured by Toyobo Co., Ltd.)

<Examples of thermal adhesive production>
(Thermal adhesive 1)
After 90 parts of the styrene / maleic acid resin 1 and 10 parts of ethyl acetate were added and mixed with stirring, a thermal adhesive 1 was obtained.

(Thermal adhesive 2-12)
Thermal adhesives 2 to 12 were obtained in the same manner as thermal adhesive 1 by blending the raw materials described in Table 1.

(Thermal adhesive 13-16)
Thermal adhesives 13 to 16 were obtained in the same manner as the thermal adhesive 1 by blending the raw materials shown in Table 2.

[Example 1]
Under the following printing conditions, Example 1 (Label 1) was obtained by sequentially printing the printing ink 1 on one side of the polyethylene film as the base material layer and the thermal adhesive 1 on the other side.

[Printing conditions]
Printing machine: Gravure printer printing film manufactured by Fuji Machine Industry Co., Ltd. U. XR <L-LDPE film> (Mitsui Chemicals Tosero Co., Ltd.)
Impression cylinder: NBR (nitrile butadiene rubber) doctor with rubber hardness of 80Hs: Ceramic plated doctor blade with a cutting edge thickness of 60 μm (base material thickness 40 μm, one side ceramic layer thickness 10 μm)
Plate: Toyo Prepress Co., Ltd., chrome hardness 1050Hv electronic engraving plate (stylus angle 130 degrees, for printing ink: 175 lines / inch, for thermal adhesive: 100 lines / inch)
Printing pressure: 2kg / cm ²
Doctor pressure: 2kg / cm ²
Printing speed: 60 m / min Drying temperature: F100 ° C

[Examples 2 to 12]
Thermal adhesives 2 to 12 were printed and laminated in the same manner as in Example 1 as described in Table 3 to obtain Examples 2 to 12 (labels 2 to 12).

[Comparative Examples 1-4]
The thermal adhesives 13-16 were printed and laminated | stacked by the method similar to Example 1 as described in Table 3, and the comparative examples 1-4 (labels 13-16) were obtained.

In addition, the base material and printing ink which were used in Examples 1-12 and Comparative Examples 1-4 are the same.

The description of Table 3 is as follows.
○: Applicable ink and thermal adhesive are printed and laminated.
Blank or “None”: The corresponding ink or thermal adhesive is not used.
Taking Example 1 as an example, a label 1 in which a thermal adhesive 1 is laminated is produced.

About the obtained labels 1-16, the adhesive strength test was done.
The evaluation results are as shown in Table 4.

<Adhesive strength test to synthetic resin container>
15mm x 60mm strips are punched from each label, and a 15mm x 30mm strip polystyrene sheet is combined with the thermal adhesive layer of the lid material and thermally bonded using a single-acting heat sealer under the following conditions. The strength of was measured with an autograph (manufactured by Shimadzu Corporation) at a peeling angle of 180 degrees and a peeling speed of 300 mm / min.
Thermal bonding conditions Thermal bonding temperature: 110 ° C
Thermal bonding condition: 1.0 second Thermal bonding pressure: 2 kg / cm ²

A: 5 N / 15 mm or more B: 3 N / 15 mm or more and less than 5 N / 15 mm Δ: 1 N / 15 mm or more and less than 3 N / 15 mm (practical level or more)
×: Less than 1N / 15mm

<Adhesive strength test 1 to substrate>
Each label is punched into a 15 mm × 60 mm strip, and a 15 mm × 30 mm T.P. U. XR <L-LDPE film> (Mitsui Chemicals Tosero Co., Ltd.) is bonded with the thermal adhesive layer of the label on the treated surface and thermally bonded under the following conditions using a single-acting heat sealer. Manufactured by Seisakusho Co., Ltd.) at a peeling angle of 180 degrees and a peeling speed of 300 mm / min.
Thermal bonding conditions Thermal bonding temperature: 110 ° C
Thermal bonding condition: 1.0 second Thermal bonding pressure: 2 kg / cm ²

A: 5 N / 15 mm or more B: 3 N / 15 mm or more and less than 5 N / 15 mm Δ: 1 N / 15 mm or more and less than 3 N / 15 mm (practical level or more)
×: Less than 1N / 15mm

<Adhesive strength test 2 to substrate>
A 15mm x 60mm strip is punched from each label, and the thermal adhesive layer of the label is aligned with the coated surface of 15mm x 30mm leuco coated paper (Daiou Paper Co., Ltd.), and heat-bonded using a single-acting heat sealer under the following conditions: The strength of the heat-bonded part was measured by an autograph (manufactured by Shimadzu Corporation) at a peeling angle of 180 degrees and a peeling speed of 300 mm / min.
Thermal bonding conditions Thermal bonding temperature: 110 ° C
Thermal bonding condition: 1.0 second Thermal bonding pressure: 2 kg / cm ²

A: 5 N / 15 mm or more B: 3 N / 15 mm or more and less than 5 N / 15 mm Δ: 1 N / 15 mm or more and less than 3 N / 15 mm (practical level or more)
×: Less than 1N / 15mm

Claims (6)

A heat seal label having a design printing layer on one side of a base material layer and a thermal adhesive layer formed by applying a thermal adhesive on the other side, wherein the thermal adhesive is styrene / A heat seal label comprising a maleic resin (A). The heat seal label according to claim 1, wherein the heat adhesive further contains an acrylic resin (B) other than the acrylic / polyester / polyolefin graft polymer dispersion. The heat seal label according to claim 1 or 2, wherein the thermal adhesive further contains an acrylic / polyester / polyolefin graft polymer dispersion (C). The heat adhesive label according to any one of claims 1 to 3, wherein the thermal adhesive further contains a polyester resin (D). A heat seal label having a design printing layer on one surface of a base material layer and a heat adhesive layer formed by applying a heat adhesive on the other surface, the following (1), ( A heat seal label characterized by 2).
(1) Thermal adhesives are styrene / maleic resin (A), acrylic resin (B) other than acrylic / polyester / polyolefin graft polymer dispersion, acrylic / polyester / polyolefin graft polymer dispersion (C) and polyester resin (D ).
(2) 20 to 45 parts by weight of styrene / maleic acid resin (A), 15 to 30 parts by weight of acrylic resin (B), 100 / part by weight of solid content of thermal adhesive, acrylic / polyester / polyolefin graft polymer dispersion ( C) is 15 to 30 parts by weight, and the polyester resin (D) is 15 to 30 parts by weight. One end of the thermal adhesive layer of the heat seal label according to any one of claims 1 to 5 is thermally bonded to the synthetic resin container, and then the heat seal label is wrapped around the outer periphery of the synthetic resin container, A package characterized by being thermally bonded so that both ends of the heat seal label overlap.

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