JP4552562B2 - Thermal label - Google Patents

Description

  The present invention relates to a heat-sensitive label applied to the surface of a plastic container such as a glass bottle or a PET bottle. More specifically, the heat-sensitive label can be easily peeled off without being peeled after use. It is about labels.

  Conventionally, printing is applied on the surface of paper, etc., and a heat-sensitive adhesive layer (adhesive layer) is applied on the back surface. This heat-sensitive adhesive layer (adhesive layer) is adhesive (adhesive) at room temperature. However, there is known a heat-sensitive label that is activated by heating to become sticky (adhesive) and sticks to a glass bottle or a plastic container.

  In particular, for the label manufacturer, unlike ordinary adhesive labels, it does not require a release mount that covers the adhesive surface before application, and is attached to glass bottles or plastic containers by heating. On the other hand, it is widely used as a heat-sensitive label that is easy to handle for adhesion and fixation.

  The basic composition of the heat-sensitive pressure-sensitive adhesive (adhesive) mentioned above consists of a water-insoluble polymer material, a tackifier, and a solid plasticizer. It refers to a pressure-sensitive adhesive (adhesive) that is activated to produce stickiness (adhesiveness) and that the stickiness (adhesiveness) lasts for a considerable period after cooling.

  Normally, the dry coating film of this adhesive (adhesive) has no tack, so there is no need for a release mount to cover this adhesive (adhesive), and it is a very economical adhesive (adhesive) Agent).

  A heat-sensitive label produced by applying such a pressure-sensitive adhesive (adhesive) to a substrate such as paper is particularly called a delayed tack (delayed adhesive) type heat-sensitive label.

  In addition, the above-mentioned delayed tack (delay adhesive) type heat-sensitive label is not sticky (adhesive) at room temperature, but is activated by heating to produce sticky (adhesive) properties. There is a hot-melt type heat-sensitive label that is attached to an adherend such as, and is solidified by cooling and bonded.

  A heat-sensitive adhesive produced using such a pressure-sensitive adhesive (adhesive) and pasted on the surface of a plastic container such as a glass bottle or PET bottle that has been distributed in the past is a heat-sensitive pressure-sensitive adhesive used for the heat-sensitive adhesive layer. (Adhesive) generally has a strong cohesive force, so once it has been pasted on the surface of a plastic container such as a glass bottle or PET bottle, it will cause an interlaminar breakage of the paper base layer when picking to peel it off. A so-called paper peeling phenomenon occurs in which only the upper layer of the paper base material layer is peeled off.

  Furthermore, even if it is soaked and peeled off, the heat-sensitive adhesive layer is firmly adhered to the surface of a plastic container such as a glass bottle or a PET bottle, which causes a phenomenon that paper remains.

Therefore, if the adhesive strength between the surface of a plastic container such as a glass bottle or PET bottle and the heat-sensitive label is kept weak and the paper is not peeled off, the label may be peeled off at the distribution stage, and in a weak state. It is also difficult to control.

  The present invention is intended to solve such problems of the prior art, and cannot be easily peeled off from the surface of a plastic container such as a glass bottle or a PET bottle at the time of distribution or use. It is an object of the present invention to provide a thermal label that can be easily peeled off by hand without peeling off or remaining paper.

  The present invention has been made to solve the above problems, and the invention according to claim 1 of the present invention is such that the display layer (2) is applied to the surface of the base material layer (1), and the back surface is provided. In the heat-sensitive label (A) to which the heat-sensitive adhesive layer (3) is applied, the base material layer (1) has at least a normal pulp layer (1a) on the front side and a resin fiber mixed layer (1b) on the back side 2 It is a heat-sensitive label characterized by being formed of a layer structure or more.

  The invention according to claim 2 of the present invention is the heat-sensitive label according to claim 1, wherein the resin fiber mixed layer (1b) is mixed with polyolefin resin fibers such as polyethylene (PE) and polypropylene (PP). This is a heat-sensitive label.

  The invention according to claim 3 of the present invention is the heat-sensitive label according to claim 1, wherein the resin fiber mixed layer (1b) is made of heat such as polyvinyl alcohol (PVA), polyethylene terephthalate (PET), or polyacrylonitrile (PAN). A heat-sensitive label characterized in that a plasticized fiber is mixed.

  The invention according to claim 4 of the present invention is the heat-sensitive label according to any one of claims 1 to 3, wherein the resin fiber addition amount of the resin fiber mixed layer (1b) is about 10 to 70%. It is a thermal label characterized by.

  The invention according to claim 5 of the present invention is the heat-sensitive label according to any one of claims 1 to 4, wherein the length of the resin fiber is in the range of 2 to 30 μm. It is.

  The heat-sensitive label of the present invention is a heat-sensitive label in which a display layer is applied to the surface of a base material layer and a heat-sensitive adhesive layer is applied to the back surface. Because it is made of two or more layers with a fiber blended layer, it cannot be easily peeled off from the surface of plastic containers such as glass bottles and PET bottles during distribution or use, but after use it will be peeled off It can be easily peeled off by hand without damaging it.

  An embodiment of the present invention will be described in detail with reference to FIG.

  FIG. 1 is a side sectional view showing one embodiment of a layer structure of a thermosensitive label according to the present invention.

  As shown in FIG. 1, the heat-sensitive label (A) of one embodiment of the present invention is provided with a display layer (2) on the surface of the base material layer (1) and a heat-sensitive adhesive layer (3) on the back surface. In the heat-sensitive label (A), the base material layer (1) is formed of at least a two-layer structure having a normal pulp layer (1a) on the front side and a resin fiber mixed layer (1b) on the back side.

The normal pulp layer (1a) and the resin fiber mixed paper layer (1b) may be separately sown and then laminated, but it is preferable to squeeze at least two layers at a time because the cost is low.

  Moreover, although it is functionally the same even in the all-layer mixed paper layer, it is not preferable because the cost increases.

  Here, one normal pulp layer (1a) which becomes the base material layer (1) of the heat-sensitive label according to the present invention, that is, paper will be described in detail.

  In general, paper is made of fibers (pulp) taken from the raw material wood, and these fibers are not entangled but stacked one by one. (Hydrogen bond).

  In addition, taking out fiber (pulp) from raw wood is called pulping, and pulp is a collection of fibers taken out from wood pieces, and has not yet been beaten or added chemicals. .

  There are several methods for this pulping, which are roughly divided into two methods: mechanical methods and chemical methods.

  First, as a mechanical method, it is the simplest method to grind the wood with a log or to make a piece of wood (chip) and grind it between two steel disks with small grooves. It is a simple way.

  What is obtained by this method is called mechanical pulp or groundwood pulp (ground pulp = GP).

  Next, as a chemical method, raw wood pieces (chips) are boiled under high temperature and high pressure using a cooking solution of sodium hydroxide (caustic soda) and sodium sulfide, and lignin other than fibers in the wood is removed. It is dissolved in the cooking liquor, then separated into fibers (pulp) and cooking liquor by a washing machine, and after removing foreign substances such as dust with a screen, the pulp separated with chemicals is bleached and pulped. Called the craft method.

  The fiber (pulp) taken out from the raw wood piece (chip) is brown, the one used as it is is unbleached pulp, and the one bleached and whitened is bleached pulp.

  It should be noted that the fibers need only be taken out and have a weak adhesive force, so it is necessary to strike them to produce small whiskers from the fibers. This is an important task in making strong paper and is called beating.

  The purpose of beating is to increase the force at which the fibers stick to each other and to cut the fibers into appropriate lengths.

  The difficulty and strength of paper breakage depends on the length of the fiber, but if it is too long, it becomes entangled and becomes a loose ball, and a uniform paper with good texture cannot be formed. Conversely, if it is too short, the strength is lost.

  Next, in order to improve the quality of paper, dyes and chemicals are mixed with fibers (pulp), but various chemicals are used according to the purpose.

For example, a sizing agent to prevent ink from bleeding, an adhesive to prevent fibers from peeling off when printing on paper or surface finishing, and letters written on the back of thin paper There are fillers to prevent see-through and the like, and water-proofing agents to make the paper strong against water.

  There are cases where these chemicals are mixed with the fibers and the paper is made and spread into the fibers.

  The raw material with the necessary chemicals added to the fiber (pulp) is called paper stock, but this paper stock is rubbed on a wire mesh and then pushed from above to squeeze out water as much as possible and dry on a hot plate. Paper is finished, but practically, it is continuously produced using a paper machine.

  First, in order to make the fiber (pulp) into a thin paper, the pulp solution (stock material) diluted with nearly 100 times water is put into the head box which is the first part of the paper machine, and pressure is applied through a narrow gap called a slice. And push it onto the wire mesh.

  This wire mesh is seamless and rotates at a constant speed, but the speed of the material coming out of the slice and the speed of the wire mesh rotate are almost the same so that the material will not be disturbed when touching the wire mesh. .

  The pulp extruded onto the wire net remains on the net, thereby forming a uniform and thin sheet.

  The moisture-rich sheet is put on a felt and sandwiched between rolls under pressure, dehydrated, and then taken over to the drying process.

  In the drying process, drying is performed through a cylindrical dryer in which the surface of an iron roll called a cylinder dryer is plated.

  There is a size press in this drying step, which is to make the paper surface stronger by letting paper and other chemicals such as starch penetrate into the paper surface.

  The dried paper is then rubbed through a number of pressured rolls called a calendar to reduce surface irregularities and give the paper a gloss.

  The finished paper is once wound up on a reel, and then finished into a small winding as necessary, or cut into a sheet.

  Thus, the normal pulp layer (1a) on the surface side constituting the base material layer (1) made of paper is a surface on which the display layer (2) for printing and the like is formed, and thus has a smooth surface. A single-sided coated paper having a clay coat layer provided thereon, more specifically, a one-sided art paper can be suitably used.

Moreover, the thickness of this base material layer (1) has a preferable basic weight of about 50-100 g / m < ² > normally.

  Next, the resin fiber mixed layer (1b) is mixed with polyolefin resin fibers such as polyethylene (PE) and polypropylene (PP).

  For example, polyethylene synthetic fiber, polypropylene synthetic fiber, and the like can be mixed.

Alternatively, polyvinyl alcohol (PVA), polyethylene terephthalate (PET)
Further, fiberized thermoplastic resins such as polyacrylonitrile (PAN) may be mixed.

  For example, polyvinyl alcohol synthetic fiber, polyester synthetic fiber, polyacrylonitrile synthetic fiber, polyamide synthetic fiber, polyvinyl chloride synthetic fiber, polyvinylidene chloride synthetic fiber, polyurethane synthetic fiber, and the like can be mixed.

  Moreover, it is preferable that the resin fiber addition amount of this resin fiber mixed paper layer (1b) is about 10 to 70%.

  If the amount of resin fiber added is less than 10%, the paper peeling strength after paper making will be weak, and conversely if it exceeds 70%, the paper may become unsatisfactory during paper making or may stick to the dryer. There is.

  The length of the resin fiber is preferably in the range of 2 μm to 30 μm.

  If the length of the resin fiber is shorter than 2 μm, the binding force with the pulp fiber becomes weak, and the effect of preventing paper peeling does not appear. Conversely, if the length is longer than 30 μm, papermaking becomes impossible.

  By providing the resin fiber mixed layer (1b) on the heat-sensitive adhesive layer (3) side in this way, the resin fibers are cross-linked in addition to hydrogen bonding between the cellulose fibers, causing surface layer peeling (peeling of the label). It is difficult.

  Next, the display layer (2) is applied to the surface of the base material layer (1), and is a layer subjected to printing ink / varnish, aluminum vapor deposition, hologram, high gloss coating, etc. for decoration.

  The printing ink includes an offset ink, a gravure ink, a silk screen ink, a flexo ink, and the like, and is one of printing materials used for forming an image line on a printing material.

  The offset ink is an ink used in an offset printing method in which printing is performed using a plate including an image line portion that receives ink on a plane of an aluminum plate and a non-image line portion that repels ink.

  The gravure ink is copper-plated on the surface of an iron cylinder (cylinder) to form a base, a release layer is provided on the copper-plated surface, further copper-plated, and the surface is polished into a mirror surface It is an ink used in a gravure printing method in which a concave portion (cell) is formed on a copper surface by a sculpture method or a corrosion method, and printing is performed by transferring the printing ink in the cell to a base material layer.

  The silk screen ink is a kind of stencil ink. Nylon, polyester and other synthetic fibers and stainless steel are used for the plate material. A resist film is formed on these plate materials except for the image line portion, and the ink is removed by a squeegee. It is an ink used in a silk screen printing method for printing through a screen.

  The flexographic ink is an ink used in a flexographic printing system in which a plate type is a relief plate and printing is mainly performed on a plate material using a photosensitive resin plate.

  As described above, there are various types of printing inks as described above, and each ink uses different raw materials in order to satisfy the required characteristics.

  Therefore, there are a great many types of ink raw materials, and it is impossible to uniformly perform this classification. However, basically, printing ink is mainly composed of a colorant, a vehicle, and an auxiliary agent.

  The colorants are roughly classified into pigments and dyes, and the pigments are further classified into organic pigments and inorganic pigments. When used in packaging materials, the colorants are light resistant, heat resistant, solvent resistant, acid resistant / resistant. In general, it is preferable to use a pigment because alkali resistance, chemical resistance, and the like are required.

  The vehicle is composed of a resin and a solvent, and this function includes a function of dispersing the colorant and transporting the colorant to the printing material through a printing machine, and a function of fixing the coloring material to the printing material.

  Various raw materials are selected depending on the conditions such as printing method, drying method, printing material, etc., but as a typical one, when the ink type is a dry oil type, the resin includes rosin-modified phenol, petroleum, alkyd, etc. As the drying oil, oils, drill oils, synthetic drying oils and the like are used, and as the solvent, a high boiling point petroleum solvent is used.

  When the ink type is an organic solvent type, polyamide, vinyl, nitrocellulose, etc. are used for the resin, and toluene, ester, ketone, alcohol, etc. are used for the solvent.

  Further, when the ink type is water-based, maleic acid-based, acrylic-based, shellac, or the like is used as the resin, and water, alcohol, glycol, or the like is used as the solvent.

  The auxiliary agent is composed of a drying adjusting agent or a film adjusting agent made of various waxes, silicon, starch, metal soap, and the like.

  Next, the varnish is provided for protecting the printing ink layer and the substrate surface layer, and a known varnish corresponding to the type of printing ink is used.

  Next, aluminum can be vapor-deposited on the surface of the base material layer (1), an aluminum foil can be bonded, hologram processing, high gloss coating, or the like can be performed.

  First, as a method of forming an aluminum vapor deposition layer on the surface of the base material layer (1) made of paper for decoration, vacuum vapor deposition, sputtering, etc. can be used, but productivity and the like are taken into consideration. Then, a vacuum evaporation method is preferable.

  There are three types of vacuum deposition methods, depending on the form of the body to be vapor-deposited. 1) Batch method: vapor deposition method of molded products, 2) take-up semi-continuous method: vacuum for roll-shaped film (web) After unwinding, vapor deposition, and winding in the system, return to the atmospheric system again and take out the vapor deposition product. 3) Unwinder (unwinding device) for roll type film (web) ) And a rewinder (winding device) are arranged in the atmospheric system, and a vapor deposition drum and an evaporation source are arranged in a vacuum system to vaporize the evaporated substance on a roll film (web). This is a completely continuous method called a to-air method and has a feature of high productivity.

  When evaporating a vaporized material on a roll-shaped film (web), a take-up semi-continuous method is particularly widespread. Describes the internal structure.

First, the constituent elements are a roll film (web), an evaporation source, an evaporation substance, a vapor deposition drum, a vacuum system, an unwinder (unwinding device), a rewinder (winding device), a guide roll, and the like.

  Next, the outline of the work process will be described. First, as a preparatory step, the door of the vacuum evaporation apparatus is opened, a roll-shaped film (web) is set in the unwinder (unwinding apparatus), and it is arranged between the unwinder and the evaporation drum. The web is caused to travel to the vapor deposition drum through a guide roll that is wound around the rewinder (winding device) via a guide roll disposed between the web and the rewinder (winding device). Preparation of vapor deposition of the evaporating substance on is completed.

  Next, the door of the vacuum deposition apparatus is closed, and the vacuum suction chamber in the vacuum deposition apparatus and the vacuum deposition chamber divided by the partition walls are set to a predetermined vacuum environment by a vacuum pump, and the web is unwound from the unwinder. The evaporating substance is evaporated on the web by evaporating the evaporating substance from the evaporation source disposed at the lower part of the evaporating drum on the web that has been run through the guide roll.

  Since the vapor deposition drum is cooled, the vaporized substance is recrystallized and fixed on the web, and the vapor deposited on the rewinder side guide roll is wound around the rewinder.

  The internal structure of the vacuum deposition apparatus is divided into a vacuum suction constant pressure chamber and a vacuum deposition chamber by partition walls. The vacuum suction constant pressure chamber is composed of an unwinder, guide roll, tension control device, speed control device, position control device, and vapor deposition drum. Some rewinders are arranged.

In the vacuum deposition chamber, a part of the deposition drum, an evaporation source, and a heating device thereof are arranged. The vacuum suction constant pressure chamber has a degree of vacuum of 1 by a vacuum pump arranged around the vacuum deposition apparatus main body. × 10 ⁰ MPa about, the vacuum deposition chamber provided via the partition wall is set to a degree 1 × 10 ^-2 MPa (SI units).

  Since the two chambers are divided by the partition walls, impurities (dust) such as gas generated from the web in the vacuum suction constant pressure chamber are unlikely to adversely affect the deposition in the vacuum deposition chamber.

  On the contrary, the radiant heat from the evaporation source arranged in the vacuum deposition chamber has little influence on the vacuum suction constant pressure chamber, so that the influence of the heat on the web is small.

  The vacuum deposition method is also a heating method: 1) Indirect resistance method, 2) Direct resistance heating method (wire feed method), 3) High frequency induction heating method, 4) Electron beam method (Electoron Beam, EB method for short) 4 There are two ways.

  Recently, the evaporative material is directly irradiated with an electron beam and scanned on the surface of the evaporative material to heat the surface of the evaporative material, convert the energy in the part hit by the electron beam, and evaporate the evaporative material. A take-type electron beam vacuum deposition method is often used.

  Next, as a method of forming an aluminum foil layer for decoration on the surface of the base material layer (1) made of paper, an aluminum foil of about 7 to 12 μm is bonded by a wet lamination method.

This wet lamination method is often used for lamination of paper (paperboard) / paper, paper / aluminum foil, paper / plastic film, cellophane / aluminum foil, etc., and an adhesive is applied to one substrate. Lamination is performed by laminating with the other base material in a wet state (moisture is present and the adhesive is not forming a film), and then the moisture is evaporated and dried with a drying apparatus. It is a method.

Next, as a method of applying a hologram for decoration on the surface of the base material layer (1) made of paper, by embossing a concavo-convex shape on the hologram forming layer and depositing a material such as aluminum. It can be used to express a rainbow 3D image and is called an embossed type.
As a specific method for applying a hologram to a thermosensitive label, for example, it is formed by sequentially laminating an approximately 20 μm hologram forming layer and a 40 nm (nanometer) aluminum vapor deposition layer on a polyester film 25 μm substrate. The method of decorating using the hologram film currently used is utilized.

  The embossed type is widely used for decorative applications such as magazines, catalog covers, premiums, displays, and packages in the form of transfer foils and labels, forgery prevention of securities, credit cards, etc., and for authenticity determination. Today, it has become the mainstream of holograms.

  Next, as a method of applying a high gloss coat for decoration on the surface of the base material layer (1) made of paper, a gloss OP varnish composed of a high gloss synthetic resin, a drying oil, a petroleum solvent and an additive is used. A method of printing by applying an offset printing method, a method of applying a vinyl-drawn varnish made of a vinyl chloride / vinyl acetate copolymer, which is a thermoplastic resin, using a roll coater or gravure roll coater, etc., acrylic aqueous There is a method of applying the resin by coating it with a stainless steel plate or a stainless steel roll, followed by press coating.

  Next, a thermoplastic resin film, a delate tack type heat sensitive adhesive, or the like is used for the heat sensitive adhesive layer (3).

  For example, as a thermoplastic resin film, polyolefin (such as linear low density polyethylene), vinyl acetate (VA) content of ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer A single layer or a single layer of a combination of two or more rubber-based resins such as coalescence (EMAA), ethylene-acrylic acid copolymer (EAA), or styrene butadiene rubber (SBR) A multilayer structure may be used by coextrusion or the like.

  Further, a delate tack type heat-sensitive adhesive obtained by adding a solid plasticizer to the above resin to form a dispersion may be used.

  The delate tack type heat-sensitive adhesive is composed of a water-insoluble polymer material as a base resin, a tackifier, and a solid plasticizer, and has no adhesiveness (adhesiveness) at room temperature. , An adhesive that, when activated, produces adhesiveness that persists for a significant amount of time after cooling.

  The water-insoluble polymer material is a component that provides an adhesive force, such as polyacrylic acid ester, polyvinyl chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer (EVA), natural rubber, synthetic rubber, acetic acid. -High molecular compounds such as acrylic acid ester copolymers are applicable, but in the present invention, acrylic resins such as polyacrylic acid esters and polymethacrylic acid esters can be preferably used.

  Next, the tackifier is a component for enhancing the tackiness when activated by heating, and resins such as rosin, rosin derivatives, and petroleum resins can be used.

The solid plasticizer is solid at room temperature and melts when heated above its melting point.
The above water-insoluble polymer materials and tackifiers are swollen and dissolved to develop tackiness and adhesiveness, and once dissolved, they do not crystallize easily. It can be done.

  For example, dicyclohexyl phthalate (DCHP), diphenyl phthalate, dihexyl phthalate, dihydroabiethyl phthalate, dimethyl isophthalate, sucrose benzoate, ethylene glycol dibenzoate, trimethylolethane tribenzoate, tribenzoyl glyceride, tetra Organic compounds that are solid at room temperature, such as benzoic acid pentaelite, sucrose octaacetate, tricyclohexyl N-cyclohexyl-P-toluenesulfonamide, and the like can be used.

  In addition, the paste type may be used as long as the interface peels between the container and the paste.

  A heat-sensitive adhesive obtained by dispersing a water-insoluble polymer material, a tackifier, and a solid plasticizer in a solvent as described above can be obtained by a known coating method such as a gravure roll coating method or a reverse roll coating method. The heat-sensitive adhesive layer (3) is formed by coating on the back surface of the material layer (1) where the display layer (2) is not formed, and is used as a heat-sensitive label for glass bottles and PET bottles.

  Hereinafter, the thermal label (A) according to the present invention will be described in more detail with specific examples.

As shown in FIG. 1, the base material layer (1) used for the heat-sensitive label (A) of the present invention is “normal pulp layer (1a) 30 g / m ² / normal pulp layer (1a) 30 g / m” from the front side. ² / resin fiber mixed paper layer (1b) 30 g / m ² ”was used to make paper by three layers.

  At this time, 50% of polypropylene fiber (fiber length: 3 to 20 μm) was added to the resin fiber mixed paper layer (1b).

  Next, gravure ink and varnish were applied as a display layer (2) to the surface of the paper as the base material layer (1) by a gravure printing method.

  Next, as a heat-sensitive adhesive layer (3) on the back surface of the base material layer (1), a terpene-based tackifier is added to an ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate (VA) content of 15%. The formed resin was formed into a thickness of 30 μm by extrusion processing.

  As described above, the obtained rolled-up original fabric for a heat-sensitive label was slit into a strip having a width of 50 mm using a slitter machine to obtain a test product.

As shown in FIG. 1, the base material layer (1) used for the heat-sensitive label (A) of the present invention is “normal pulp layer (1a) 30 g / m ² / normal pulp layer (1a) 30 g / m” from the front side. ² / resin fiber mixed paper layer (1b) 30 g / m ² ”was used to make paper by three layers.

  At this time, 50% of polypropylene fiber (fiber length: 3 to 20 μm) was added to the resin fiber mixed paper layer (1b).

  Next, gravure ink and varnish were applied as a display layer (2) to the surface of the paper as the base material layer (1) by a gravure printing method.

  Next, a terpene-based tackifier is added to the ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate (VA) content of 15% as a heat-sensitive adhesive layer (3) on the back surface of the base material layer (1). The prepared easy peel film having a thickness of 30 μm was bonded by a wet lamination method.

  As described above, the obtained rolled-up original fabric for a heat-sensitive label was slit into a strip having a width of 50 mm using a slitter machine to obtain a test product.

  Below, the comparative example of the thermosensitive label (A) which concerns on this invention is demonstrated.

For the base material layer (1) of the heat-sensitive label (A) used in this comparative example, a piece of art paper having a thickness of 104.7 g / m ² was used.

  Next, gravure ink and varnish were applied as a display layer (2) to the surface of the piece art paper as the base material layer (1) by a gravure printing method.

  Next, a polyethylene terephthalate film (PET) having a thickness of 12 μm was bonded to the back surface of the base material layer (1) by a dry lamination method as a film for preventing paper peeling.

  Further, a resin obtained by adding a terpene tackifier to an ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate (VA) content of 15% as a heat-sensitive adhesive layer (3) on the back surface of the film for preventing paper peeling. Was formed into a thickness of 30 μm by extrusion.

  As described above, the obtained rolled-up original fabric for a heat-sensitive label was slit into a strip having a width of 50 mm using a slitter machine to obtain a test product.

For the base material layer (1) of the heat-sensitive label (A) used in this comparative example, a piece of art paper having a thickness of 104.7 g / m ² was used.

  Next, gravure ink and varnish were applied as a display layer (2) to the surface of the piece art paper as the base material layer (1) by a gravure printing method.

  Next, as a heat-sensitive adhesive layer (3) on the back surface of the base material layer (1), a terpene-based tackifier is added to an ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate (VA) content of 15%. The formed resin was formed into a thickness of 30 μm by extrusion processing.

  As described above, the obtained rolled-up original fabric for a heat-sensitive label was slit into a strip having a width of 50 mm using a slitter machine to obtain a test product.

  A total of four types of thermal labels of Example 2 and Comparative Example 2 of the thermal label according to the present invention thus produced were labeled on a glass bottle having a diameter of 50Φ × 100 mm in height and a PET bottle, respectively. Evaluations were made regarding the adhesive strength with the adherend, the peeled portion, and the paper peeling.

  The labeling conditions were set at a drum temperature of 115 ° C., a hot air temperature of 350 ° C., and a labeling speed of 100 lines / min.

表１は、本発明に係る感熱ラベルの発明品と比較例とを評価した結果表である。

Table 1 is a table showing the results of evaluating the inventive products and comparative examples of the thermal label according to the present invention.

  The evaluation method and evaluation result in each evaluation item were expressed as follows.

  The cost-related evaluation method was to calculate the cost of the material cost of the thermal label, and the evaluation result was expressed as cheap: ◎ standard: ○ high: ×.

  The evaluation method related to the adhesive strength is the adhesive strength (peel strength) between the glass bottle that is the adherend surface and the surface of the PET bottle and the thermosensitive label, and evaluated by 180 ° peel in accordance with JIS Z1707. The numerical value of adhesive strength (peel strength) and good: ◯ not measured:-.

  The evaluation method of the peeled portion visually evaluated the state of the peeled portion when the heat-sensitive label was manually peeled from the container, and the evaluation result was expressed by the container / adhesive layer interface or the paper delamination.

  The evaluation method of paper peeling evaluated visually the state of paper peeling when the heat-sensitive label was manually peeled from the container, and was expressed as “None”: “Yes”: “X”.

  Comprehensive evaluation was expressed as good: ○ bad: x.

  From the results of Table 1, when considering the thermal label and the comparative example according to the present invention, Example 1 of the product of the present invention is good in all the evaluation items, and Example 2 is compared with Example 1, All evaluation items were good except for the cost.

  In Example 3 of the comparative example, since the paper peeling prevention film was laminated, the physical properties were good. However, since the paper peeling prevention film was laminated, there was a problem in the cost of the thermal label and it was not practical. .

  Example 4 of the comparative example is not practical because the peeled portion causes paper delamination and paper peeling occurs.

FIG. 1 is a side sectional view showing one embodiment of a layer structure of a thermosensitive label according to the present invention.

Explanation of symbols

A ... heat-sensitive label 1 ... substrate layer 1a ... normal pulp layer 1b ... resin fiber mixed paper layer 2 ... display layer 3 ... heat-sensitive adhesive layer

Claims (4)

In a heat-sensitive label in which a display layer is applied on the surface of a base material layer and a heat-sensitive adhesive layer is applied on the back surface, the base material layer has at least a normal pulp layer on the front surface side and a resin fiber mixed layer on the back surface side. A heat-sensitive label, wherein the heat-sensitive label is formed of a structure or more, and the length of the resin fiber is in the range of 2 μm to 30 μm . The heat-sensitive label according to claim 1, wherein the resin fiber is a polyolefin resin fiber . Thermal label of claim 1, wherein the resin fibers in which the thermoplastic resin into fibers.   The heat-sensitive label according to any one of claims 1 to 3, wherein a resin fiber addition amount of the resin fiber mixed paper layer is about 10 to 70%.

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