Heat-sensitive label and container attached with heat-sensitive label

Abstract

To provide a heat-sensitive label that uses a hot-melt adhesive agent that has stable adhesiveness with a long open time, and does not generate blocking or jamming and a container.SOLUTION: A heat-sensitive label comprising a base layer 4 and an adhesive layer, wherein the adhesive layer satisfies any one of the following (1) to (3): (1) having an adhesive portion (A) 1 and an uncoated portion (B) 2, with Ma:Mb=1:99 to 80:20; (2) having an adhesive portion (A) and an adhesive portion (C), with Ma:Mc=1:99 to 80:20; (3) having an adhesive portion (A), an uncoated portion (B), and an adhesive portion (C), with Ma:(Mb+Mc)=1:99 to 80:20. Ma: area of the adhesive portion (A) per unit area Mb: area of the uncoated portion (B) per unit area Mc: area of the adhesive portion (C) per unit area.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat-sensitive label and a container to which the heat-sensitive label is attached. [Background technology]

[0002] Hot melt adhesives are solvent-free, making them environmentally and work-friendly. They also have many other advantages, such as the ability to quickly roll up substrates such as film and paper substrates after being heated and melted, allowing for compact coating machines, and the ability to quickly cool and solidify when bonding substrates together in a molten state, allowing for instant adhesive properties.

[0003] Tack labels are often used for labels on glass and plastic bottles, but because the release paper (film) generates waste, reducing waste has been an issue. Therefore, heat-sensitive labels have attracted attention as a type of tack-free label. Patent Document 1 uses delayed tack as a heat-sensitive label adhesive, but delayed tack has the problem of using dicyclohexyl phthalate (DCHP), a solid plasticizer suspected of being an endocrine disruptor. Patent Document 2 uses hot melt as a heat-sensitive label adhesive without DCHP, but hot melt adhesives have problems such as a short open time that makes it difficult to achieve stable adhesion. Furthermore, extending the open time to ensure stable adhesion can cause blocking during transport of the coated product, resulting in adhesive adhesion to the printed surface, and adhesive adhesion to the labeler's cutter during labeling, causing jamming. These issues have prevented widespread adoption. Jamming, in particular, tends to occur more frequently at higher labeling speeds, posing a challenge to the practical application of heat-sensitive labels using hot melt adhesive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 55-16055 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-137438 Summary of the Invention [Problem to be solved by the invention]

[0005] Heat-sensitive labels have the advantage of being environmentally friendly. However, as mentioned above, heat-sensitive labels using hot melt adhesives have issues such as adhesive stability, blocking, and jamming.

[0006] An object of the present invention is to provide a heat-sensitive label and container using a hot melt adhesive that has a long open time, stable adhesive properties, and is free from blocking and jamming. [Means for solving the problem]

[0007] The present disclosure relates to the following heat-sensitive label and container to which it is attached. [1] A heat-sensitive label comprising a substrate layer and an adhesive layer, wherein the adhesive layer satisfies any one of the following (1) to (3): The relationship between the height (La) of the adhesive part (A) and the height (Lc) of the adhesive part (C) is La>Lc, A heat-sensitive label characterized in that the adhesive portions (A) and (C) are made of a hot melt adhesive. (1) It has an adhesive part (A) and an uncoated part (B), and Ma:Mb=1:99 to 80:20 (2) It has adhesive parts (A) and (C), and Ma:Mc=1:99 to 80:20 (3) Having an adhesive section (A), an uncoated section (B), and an adhesive section (C), and Ma:(Mb+Mc)=1:99 to 80:20 Ma: Area of ​​adhesive joint (A) per unit area Mb: Area of ​​uncoated part (B) per unit area Mc: Area of ​​adhesive bond per unit area (C)

[0008] [2] A heat-sensitive label comprising a substrate layer and an adhesive layer, wherein the adhesive layer satisfies any one of the following (1') to (3'): The relationship between the height (La) of the adhesive part (A) and the height (Lc) of the adhesive part (C) is La>Lc, A heat-sensitive label characterized in that the adhesive portions (A) and (C) are made of a hot melt adhesive. (1') Adhesive sections (A) and uncoated sections (B) are arranged alternately, and Ma:Mb = 1:99 to 80:20 (2') Adhesive sections (A) and adhesive sections (C) are alternately arranged, and Ma:Mc=1:99 to 80:20 (3') The adhesive portion (A), adhesive portion (C), adhesive portion (A) and uncoated portion (B) are arranged in this order, and Ma:(Mb+Mc)=1:99 to 80:20

[0009] [3] The heat-sensitive label as described above, wherein the height (La) of the adhesive portion (A) is 10 to 500 μm.

[0010] [4] The above-mentioned heat-sensitive label, wherein the substrate is selected from the group consisting of paper, plastic film, and synthetic paper.

[0011] [5] A container with the heat-sensitive label attached. [Effects of the Invention]

[0012] The present disclosure has the excellent effect of providing a heat-sensitive label and container using a hot melt adhesive that has a long open time, stable adhesiveness, and is free from blocking or jamming. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view partially illustrating a heat-sensitive label of the present invention having an adhesive portion and an uncoated portion. [Figure 2] FIG. 1 is a schematic cross-sectional view partially illustrating a heat-sensitive label of the present invention, in which the adhesive portions have two different heights. [Figure 3]FIG. 1 is a schematic cross-sectional view partially illustrating a heat-sensitive label of the present invention having adhesive portions with two different heights and uncoated portions. [Figure 4] , [Figure 5] and [Figure 6] FIG. 1 is a schematic plan view showing the shapes of an adhesive portion (A), an uncoated portion, and an adhesive portion (C) of a heat-sensitive label of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present disclosure will be described in detail below. It goes without saying that other embodiments are also included in the scope of the present invention as long as they are consistent with the spirit of the present invention.

[0015] In this specification, a numerical range specified using "~" includes the numerical values ​​before and after "~" as the range of the lower and upper limits. Unless otherwise noted, each of the various components appearing in this specification may be used independently, either singly or in combination of two or more. Furthermore, "parts" and "%" mean "parts by mass" and "% by mass," respectively, unless otherwise specified. Represents.

[0016] A hot melt adhesive is an adhesive that becomes liquid when heated and is used to bond objects together, and once cooled, returns to a solid state and has the property of bonding objects together.

[0017] <Thermal label> The heat-sensitive label of the present invention comprises a base layer and an adhesive layer, the adhesive layer satisfies any one of the following (1) to (3) and (1') to (3'), the relationship between the height (La) of the adhesive portion (A) and the height (Lc) of the adhesive portion (C) is La > Lc, and the adhesive portions (A) and (C) are made of a hot melt adhesive. (1) It has an adhesive part (A) and an uncoated part (B), and Ma:Mb = 1:99 to 80:20 (2) Having adhesive part (A) and adhesive part (C), Ma:Mc = 1:99 to 80:20 (3) Having an adhesive section (A), an uncoated section (B), and an adhesive section (C), Ma:(Mb+Mc)=1:99 to 80:20 (1') Adhesive sections (A) and uncoated sections (B) are arranged alternately, with Ma:Mb = 1:99 to 80:20 (2') Adhesive sections (A) and adhesive sections (C) are alternately arranged, and Ma:Mc=1:99 to 80:20 (3') Adhesive section (A), adhesive section (C), adhesive section (A) and uncoated section (B) are arranged in this order, and Ma:(Mb+Mc)=1:99 to 80:20 Ma: Area of ​​adhesive joint (A) per unit area Mb: Area of ​​uncoated part (B) per unit area Mc: Area of ​​adhesive bond per unit area (C)

[0018] In this specification, a heat-sensitive label whose adhesive layer satisfies requirement (1) will be referred to as heat-sensitive label (1), a heat-sensitive label whose adhesive layer satisfies requirement (2) will be referred to as heat-sensitive label (2), a heat-sensitive label whose adhesive layer satisfies requirement (3) will be referred to as heat-sensitive label (3), a heat-sensitive label whose adhesive layer satisfies requirement (1') will be referred to as heat-sensitive label (1'), a heat-sensitive label whose adhesive layer satisfies requirement (2') will be referred to as heat-sensitive label (2'), and a heat-sensitive label whose adhesive layer satisfies requirement (3') will be referred to as heat-sensitive label (3').

[0019] The heat-sensitive label of the present invention only needs to have a substrate layer and an adhesive layer. The adhesive layer may be provided directly on the substrate layer, or an intermediate layer such as an ink layer may be provided between the substrate layer and the adhesive layer.

[0020] The height (La) of the adhesive part (A) and the height (Lc) of the adhesive part (C) refer to the respective coating heights.

[0021] The shapes of the adhesive portions (A), adhesive portions (C), and uncoated portions (B) that make up the adhesive layer are not particularly limited. They may be any shape, such as linear, lattice, wavy, or dotted, or may be a combination of multiple shapes. The shape can be determined arbitrarily depending on the application. In consideration of productivity, a heat-sensitive label that satisfies any of the above conditions (1') to (3') in which each portion is alternately arranged is preferred, and it is further preferred that each portion be linear in shape.

[0022] Schematic cross-sectional views partially illustrating the heat-sensitive label of the present invention are shown in Figures 1, 2, and 3. Figure 1 shows a heat-sensitive label (1') in which adhesive sections (A) and uncoated sections (B) are arranged alternately, Figure 2 shows a heat-sensitive label (2') in which adhesive sections (A) and adhesive sections (C) are arranged alternately, and Figure 3 shows a heat-sensitive label (3') in which adhesive sections (A), adhesive sections (C), adhesive sections (A), and uncoated sections (B) are arranged in this order.

[0023] <Thermal labels (1) and (1')> The heat-sensitive label (1) is a heat-sensitive label having a base layer and an adhesive layer, the adhesive layer having adhesive sections (A) and uncoated sections (B), and having an Ma:Mb ratio of 1:99 to 80:20. The heat-sensitive label (1') is a heat-sensitive label (1) in which the adhesive sections (A) and uncoated sections (B) are arranged alternately. From the viewpoint of adhesiveness and anti-jamming properties, Ma:Mb=10:90 to 70:30 is preferred, Ma:Mb=20:80 to 60:40 is more preferred, and Ma:Mb=30:70 to 60:40 is even more preferred.

[0024] <Thermal labels (2) and (2')> The heat-sensitive label (2) is a heat-sensitive label having a base layer and an adhesive layer, the adhesive layer having adhesive parts (A) and adhesive parts (C), and Ma:Mc=1:99 to 80:20. The heat-sensitive label (2') is a heat-sensitive label (2) in which adhesive parts (A) and adhesive parts (C) are arranged alternately. From the viewpoint of adhesiveness and anti-jamming properties, Ma:Mc=10:90 to 70:30 is preferred, Ma:Mc=20:80 to 60:40 is more preferred, and Ma:Mc=30:70 to 60:40 is even more preferred.

[0025] <Thermal labels (3) and (3')> The heat-sensitive label (3) is a heat-sensitive label having a base layer and an adhesive layer, the adhesive layer having an adhesive portion (A), an uncoated portion (B), and an adhesive portion (C), and Ma:(Mb+Mc)=1:99 to 80:20. The heat-sensitive label (3') is a heat-sensitive label (3) in which the adhesive portion (A), adhesive portion (C), adhesive portion (A), and uncoated portion (B) are arranged in this order. From the viewpoint of adhesiveness and anti-jamming properties, Ma:(Mb+Mc) is preferably 10:90 to 70:30, more preferably 20:80 to 60:40, and even more preferably 30:70 to 60:40.

[0026] In the heat-sensitive label of the present invention, the height (La) of the adhesive portion (A) is preferably 10 to 500 μm from the viewpoints of adhesiveness and anti-jamming properties. From the viewpoint of adhesiveness, the lower limit is more preferably 15 μm or more, and even more preferably 20 μm or more, and from the viewpoint of anti-jamming properties, the upper limit is more preferably 100 μm or less, and even more preferably 50 μm or less.

[0027] The average height (L) of the adhesive part of the heat-sensitive label is preferably 1 to 30 μm. From the viewpoint of adhesiveness and anti-jamming properties, the average height (L) is preferably 5 to 20 μm, more preferably 8 to 15 μm. The average height (L) of the adhesive portion of the heat-sensitive label in the present invention is the average height of the adhesive portion per total length of the coated width of the adhesive portion and the width of the uncoated portion in each coating pattern. Specifically, it is as follows: The average height of the adhesive portion of the thermal labels (1) and (1') means the average height of the adhesive portion per total length (Wa+Wb) of the coated width (Wa) of the adhesive portion (A) and the width (Wb) of the uncoated portion (B), and is calculated by (La×Wa) / (Wa+Wb). The average height of the adhesive joints in the thermal labels (2) and (2') means the average height of the adhesive joints per total length (Wa+Wc) of the coated width (Wa) of the adhesive joint (A) and the coated width (Wc) of the adhesive joint (C), and is calculated by (La×Wa+Lc×Wc) / (Wa+Wc). The average height of the adhesive portion of the thermal labels (3) and (3') means the average height of the adhesive portion per total length (Wa+Wc+Wa+Wb) of the coated width (Wa) of the adhesive portion (A), the coated width (Wc) of the adhesive portion (C), the coated width (Wa) of the adhesive portion (A), and the width (Wb) of the uncoated portion (B), and is calculated by (La×Wa+Lc×Wc+La×Wa) / (Wa+Wc+Wa+Wb).

[0028] <Base material layer> The substrate used for the substrate layer (hereinafter also referred to as label substrate) can be a plastic film such as biaxially oriented polypropylene (OPP) or polyethylene terephthalate (PET), paper made from plant fibers such as pulp, wood, or bamboo, synthetic paper made from plastic polymers (polyethylene, polypropylene, etc.), or stone paper made primarily from limestone. A thin, hard substrate can also be used. It is preferable to select the substrate from the group consisting of paper, plastic film, and synthetic paper.

[0029] <Adhesive layer> The adhesive layer consists of an adhesive portion (A) and an uncoated portion (B) and / or an adhesive portion (C). The adhesive portion (A) and the adhesive portion (C) are formed with a hot melt adhesive. The hot melt adhesives used in the adhesive portion (A) and the adhesive portion (C) may be the same or different.

[0030] The hot melt adhesive is used to form the adhesive portions (A) and (C) in the adhesive layer of the heat-sensitive label. In terms of adhesiveness and anti-blocking properties, the hot melt adhesive preferably contains an ethylene-unsaturated ester copolymer, a tackifier, and a wax.

[0031] In the hot melt adhesive, the ethylene-unsaturated ester copolymer, tackifier, and wax preferably comprise 10 to 70% by mass of the ethylene-unsaturated ester copolymer, 10 to 70% by mass of the tackifier, and 5 to 70% by mass of the wax, with the total being 100% by mass. By including 10 to 70% by mass of the ethylene-unsaturated ester copolymer, it is possible to maintain good adhesiveness (cohesive strength). It is even more preferable that it is 20 to 50% by mass. By including 10 to 70% by mass of the tackifier, it is possible to maintain good adhesiveness (adhesion). It is even more preferable that it is 20 to 50% by mass. By including 5 to 70% by mass of the wax, it is possible to maintain good open time and anti-blocking properties. It is even more preferable that it is 20 to 50% by mass.

[0032] In 100% by mass of the hot melt adhesive, the total content of the ethylene-unsaturated ester copolymer, tackifier resin, and wax is preferably 60 to 100% by mass. By setting the content within this range, adhesiveness and anti-blocking properties can be more effectively achieved. A more preferred range is 70 to 100% by mass, and an even more preferred range is 80 to 100% by mass.

[0033] [Ethylene-unsaturated ester copolymer] Examples of the ethylene-unsaturated ester copolymer include an ethylene-(meth)acrylic acid ester copolymer and an ethylene-vinyl acetate copolymer, and in particular, an ethylene-vinyl acetate copolymer is preferred in terms of adhesiveness. The ethylene-vinyl acetate copolymer preferably has a vinyl acetate content of 26% by mass or more but less than 45% by mass. If the vinyl acetate content is 45% by mass or more, blocking properties decrease, and if the vinyl acetate content is less than 26% by mass, adhesive properties decrease. The upper limit of the vinyl acetate content is more preferably less than 35% by mass.

[0034] The melt mass flow rate (MFR) of the ethylene-vinyl acetate copolymer at 190°C under a load of 2.16 kg is preferably 12 to 350 g / 10 min. From the viewpoint of anti-blocking properties and adhesiveness, it is more preferably 100 to 200 g / 10 min. The MFR is a value measured in accordance with JIS K7210.

[0035] [Tackifier] The tackifier plays a role in improving adhesiveness. Examples of the tackifier include, but are not limited to, phenolic resins, modified phenolic resins, terpene phenolic resins, xylene phenolic resins, cyclopentadiene-phenolic resins, xylene resins, aliphatic, alicyclic, and aromatic petroleum resins, hydrogenated aliphatic, alicyclic, and aromatic petroleum resins, phenol-modified petroleum resins, rosin ester resins, hydrogenated rosin, acid-modified rosin, hydrogenated rosin ester resins, low-molecular-weight polystyrene resins, terpene resins, and hydrogenated terpene resins. From the viewpoint of adhesiveness and anti-blocking properties, it is preferable that the resin be at least one selected from the group consisting of rosin-based tackifying resins, terpene-based tackifying resins, and petroleum-based tackifying resins. When the adherend is a glass or metal container, a tackifier having a polar group such as a carboxylic acid is suitable from the viewpoint of adhesiveness.

[0036] The softening point of the tackifier is preferably 70 to 140°C from the viewpoint of open time and blocking properties, and from the viewpoint of open time, the lower limit of the softening point is more preferably 90°C or higher, and even more preferably 100°C or higher. On the other hand, from the viewpoint of adhesiveness, the upper limit of the softening point is more preferably 120°C or lower, and even more preferably 110°C or lower. The method for measuring the softening point will be described in detail in the Examples.

[0037] The acid value of the tackifier is not particularly limited, but is preferably 20 to 300 mgKOH / g when the container to which the heat-sensitive label is attached is made of a bottle, metal, etc. A higher acid value will result in better results, as the label will not peel off when condensation forms when attached to a highly polar container such as a bottle or metal. The method for measuring the acid value will be described in detail in the Examples.

[0038] [wax] Waxes play a role in improving blocking properties, and examples of waxes include carnauba wax, candelilla wax, montan wax, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, oxides of these waxes, saturated fatty acid triglycerides, ethylene-acrylic acid copolymer wax, and ethylene-methacrylic acid copolymer wax. In view of blocking properties and open time, the preferred wax is a saturated fatty acid triglyceride.

[0039] Saturated fatty acid triglycerides refer to fats and oils that are liquid at room temperature due to their relatively low melting point and therefore contain a large amount of unsaturated fatty acid triglycerides, and are then hydrogenated to increase the proportion of saturated fatty acid triglycerides with higher melting points, resulting in a solidified fat and oil at room temperature. Typical fats and oils include palm oil, olive oil, rapeseed oil, sesame oil, cottonseed oil, soybean oil, sunflower oil, safflower oil, rice bran oil, corn oil, coconut oil, linseed oil, beef tallow, lard, and fish oil, and their hydrogenated oils (hydrogenated products) are examples of saturated fatty acid triglycerides. Among these, hydrogenated rapeseed oil is preferred in terms of anti-blocking properties, open time, and adhesive properties.

[0040] The fats and oils before hardening consist of a mixture of fatty acid triglycerides having 6 to 22 carbon atoms, and are hardened by hydrogenation to increase the melting point. The melting point of the saturated fatty acid triglyceride is preferably 50 to 100°C, more preferably 65 to 80°C. When the melting point of the saturated fatty acid triglyceride is 50 to 100°C, good anti-blocking properties and long open time performance can be obtained. The method for measuring the melting point will be described in detail in the Examples.

[0041] The saturated fatty acid in the saturated fatty acid triglyceride preferably does not have a hydroxyl group, since the presence of a hydroxyl group increases the open time but may result in poor blocking properties.

[0042] The hot melt adhesive used in the heat-sensitive label of the present invention may further contain other components as long as the effects of the present invention are not impaired. Examples of other components include colorants, antiblocking agents, inorganic fillers, antioxidants, bulking agents, flame retardants, plasticizers, antistatic agents, light stabilizers, UV absorbers, and heavy metal deactivators. These components may be used alone or in combination of two or more.

[0043] The colorant can be a commonly known colorant such as red, blue, green, yellow, etc. The colorant may be any of pigments, dyes, and coloring matters, and examples thereof include monoazo-based, disazo-based, azo-lake-based, benzimidazolone-based, perylene-based, diketopyrrolopyrrole-based, condensed azo-based, anthraquinone-based, quinacridone-based, phthalocyanine-based, and anthraquinone-based colorants. Examples of pigment-based colorants include pigments, perylene-based, monoazo-based, condensed azo-based, isoindolinone-based, titanium oxide, and carbon.

[0044] Examples of the anti-blocking agent include silicone, unsaturated fatty acid amides such as stearic acid amide, oleic acid amide, erucic acid amide and behenic acid amide.

[0045] Examples of the inorganic filler include particles and fibers of metals, metal oxides, metal hydroxides, etc. Specific examples include glass fibers, carbon fibers, calcium silicate, calcium titanate, aluminum borate fibers, flaked glass, talc, kaolin, mica, hydrotalcite, calcium carbonate, zinc carbonate, zinc oxide, calcium hydrogen phosphate, wollastonite, silica, zeolite, alumina, boehmite, aluminum hydroxide, titanium oxide, silicon oxide, magnesium oxide, calcium silicate, alumina sodium silicate, magnesium silicate, carbon nanotubes, graphite, copper, silver, aluminum, nickel, iron, calcium fluoride, mica, montmorillonite, and apatite.

[0046] Examples of the antioxidant include high molecular weight hindered polyhydric phenols, triazine derivatives, high molecular weight hindered phenols, dialkyl phenol sulfides, 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol), 4,4'-methylene-bis-(2,6-di-tert-butylphenol), 2,6-di-tert-butyl-p-cresol, 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol), 2,5-di-tert-butylhydroquinone, 2,2, Examples include 4-trimethyl-1,2-dihydroquinoline, 2,2,4-trimethyl-1,2-dihydroquinoline polymers, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, nickel dibutyl dithiocarbamate, 1-oxy-3-methyl-4-isopropylbenzene, 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), and 2-mercaptobenzimidazole. Antioxidants can be used to prevent thermal degradation and decomposition.

[0047] Examples of the filler include wet silica, aluminum hydroxide, aluminum oxide, magnesium oxide, montmorillonite, mica, smectite, organically modified montmorillonite, organically modified mica, and organically modified smectite.

[0048] Examples of the flame retardant include phosphorus-containing compound flame retardants, halogen-containing compound flame retardants, sulfonic acid metal salt flame retardants, and silicon-containing compound flame retardants.

[0049] Examples of the plasticizer include phthalate ester-based plasticizers, polyester-based plasticizers, aliphatic dibasic acid ester-based plasticizers, aliphatic monobasic acid ester-based plasticizers, phosphate ester-based plasticizers, citrate ester-based plasticizers, epoxy-based plasticizers, trimellitate ester-based plasticizers, tetrahydrophthalate ester-based plasticizers, glycol-based plasticizers, and bisphenol A alkylene oxide derivatives.

[0050] The antistatic agent may be any agent commonly used as an antistatic agent for plastics, and specific examples thereof include nonionic surfactants (e.g., fatty acid esters of polyhydric alcohols, ethylene oxide adducts of alkylamines, and fatty acid esters of ethylene oxide adducts of alkylamines), anionic surfactants (e.g., alkylbenzenesulfonates, higher alcohol sulfate ester salts), cationic surfactants (e.g., aliphatic amine salts, quaternary ammonium salts), and amphoteric surfactants (e.g., imidazoline type, betaine type, etc.).

[0051] Examples of the light stabilizer include hindered amine compounds and benzoate compounds.

[0052] Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers, triazine-based ultraviolet absorbers, and benzotriazole-based ultraviolet absorbers.

[0053] Examples of the heavy metal deactivator include salicylic acid derivatives, hydrazide derivatives, and oxalic acid amide derivatives.

[0054] [Hot melt adhesive manufacturing method] The hot melt adhesive can be produced by adding the ethylene-unsaturated ester copolymer and the tackifier to a wax melt in a melting pot equipped with a stirrer and mixing them together. Alternatively, the hot melt adhesive can be produced by mixing and dispersing the ingredients in an extruder and extruding the molten mixture from a nozzle at the tip of the extruder.

[0055] <Thermal label manufacturing method> The heat-sensitive label can be produced by a known method, for example, by applying a hot melt adhesive to a label substrate and then cooling it. An example of a method for applying a hot-melt adhesive to a label substrate is to heat it to a liquid state and then form a layer using a coater. Examples of coaters include blade coaters, bar coaters, comma coaters, gravure coaters, roll coaters, reverse roll coaters, die coaters, and T-die coating. After application, an organic solvent may be added to adjust the viscosity by cooling. When an organic solvent is used, the organic solvent may be removed in a hot air drying oven.

[0056] <Containers with heat-sensitive labels> The container having a heat-sensitive label attached thereto refers to a container having a heat-sensitive label of the present invention attached thereto. The container may be made of glass, ceramic, plastic, metal, or the like.

[0057] The glass can be transparent, brown, or colored (blue, red, green, etc.) The surface of the glass bottle can be untreated or coated with a resin such as cold coating, hot coating, or polyethylene (PE) coating. The heat-sensitive label of the present invention can also be applied to glass products other than glass bottles, metal products such as metal containers, and other materials.

[0058] As for plastics, any material that can be used as a container by itself can be used, such as olefins such as high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polypropylene, polystyrene, polyester (such as polyethylene terephthalate), polycarbonate, and vinyl chloride. Furthermore, if a multilayer structure is possible, a foam layer can be placed on one side of the container to improve the impact resistance of the container, and the same resin can be extruded without foaming to create a multilayer container.

[0059] As the ceramic container, pottery or china clay containers can be used, and as the metal container, cans made of aluminum, steel, etc. can be used.

[0060] Methods for attaching heat-sensitive labels include heating the label and attaching it to the bottle, or setting the label in the mold beforehand when in-mold molding plastic containers, etc., and then using the heat generated during molding to adhere the label to the container. In-mold molding methods include vacuum forming, pressure forming, extrusion blow molding, injection molding, injection blow molding, and biaxial stretch blow molding.

[0061] When applying a label to the exterior surface of a resin container, such as a polyolefin container or a polyethylene terephthalate container, using processes such as vacuum forming, pressure forming, extrusion blow molding, injection molding, injection blow molding, and biaxial stretch blow molding, an in-mold labeling method is known in which an in-mold label is pre-positioned on the cavity surface of a molding die and then heat-sealed to the exterior surface of the container as the container is being molded. This in-mold labeling method has the advantage that the in-mold label can be adhered to the entire exterior surface of the container, making the label less likely to peel off from the container and facilitating large-area labeling. Furthermore, this method is preferred because it can increase the rigidity of the container, enable the container to be made thinner, provide excellent design, and enable labor-saving and space-saving processes.

[0062] These application methods allow a heat-sensitive label with a hot-melt adhesive layer (not sticky at room temperature) to be applied to an adherend while heating, eliminating the need for release paper, preventing contamination of the application machine, making it easy to align the labeling, and preventing blocking during normal transportation and handling. Eliminating the need for release paper also reduces waste, making these labels environmentally friendly.

[0063] By using the heat-sensitive label of the present invention, the performance of the heat-sensitive label can be significantly improved, with a long open time and good anti-jamming properties. The reason is that when the heat-sensitive label is adhered to a substrate after heating, the open time of the hot melt adhesive is long, so that the label can be easily adhered to the substrate even if the heat of the hot melt adhesive is absorbed by the substrate. On the other hand, when the heat-sensitive label is adhered to a container with a labeler, jamming does not occur when cutting the label. [Example]

[0064] Next, the present invention will be described based on specific examples in comparison with comparative examples, but the present invention is not limited to these. Unless otherwise specified, "parts" and "%" in the examples represent "parts by mass" and "% by mass", respectively.

[0065] [Melt Mass-Flow Rate (MFR) Measurement of Ethylene-Unsaturated Ester Copolymer] The MFR of the ethylene-unsaturated ester copolymer was measured in accordance with JIS K 7210. Specifically, a resin placed in a cylindrical extrusion-type plastometer was heated and pressurized (10 g) at 190°C under a load of 2.16 kg, and the amount of resin extruded from the opening at the bottom of the container in 10 minutes was measured.

[0066] [Measuring the melting point of wax] The melting point of the wax was measured by the melting point measurement method described in the Japanese Standards for Food Additives (8th edition). Specifically, dry powdered wax was placed in a capillary tube, tightly packed, and then heated to approximately 100°C. The melting point was determined as the temperature at which the wax completely melted and became transparent.

[0067] [Measurement of softening point of tackifier] The softening point of the tackifier was measured in accordance with JIS K 6863. Specifically, after filling a ring base with the tackifier, a ball (specified in JIS B1501: steel ball / diameter 9.53 mm / mass 3.5±0.05 g) was placed on it, and the softening point was determined by measuring the temperature at which the ball dropped at a heating rate of 5°C / °C using an ASP-KG4 tube-type automatic softening point tester (manufactured by Meitex Corporation).

[0068] [Measurement of the acid value of tackifier] The acid value of a tackifier is the number of milligrams of potassium hydroxide (KOH) required to neutralize 1 g of sample, and is a value measured in accordance with JIS K5601-2-1 Acid Value (Titration Method). Specifically, 1 g of sample was dissolved in 2 volumes of toluene and 1 volume of ethanol [95% (V / V)], and then titrated with potassium hydroxide solution using a phenolphthalein indicator to determine the acid value.

[0069] (Production Example 1) 30 parts of hardened rapeseed oil as a wax, 0.1 part of IRGANOX 1010 as an additive, and 0.2 parts of silicone KF96-100CS were placed in a container and heated to 150°C to melt, and then 40 parts of Ultrathene 720 as an ethylene-vinyl acetate copolymer and 30 parts of Halitac 4821 as a tackifier were gradually added while stirring with a stirrer. The ethylene-vinyl acetate copolymer was completely dissolved, yielding the hot melt adhesive of Production Example 1.

[0070] (Manufacturing Examples 2 to 11) A hot melt adhesive was produced in the same manner as in Production Example 1, except that the materials and blending amounts shown in Table 1 were used.

[0071] The materials listed in Table 1 are described below.

[0072] Ethylene-unsaturated ester copolymer Evaflex P1007 (Mitsui Dow Polychemicals, MFR: 9g / 10min) Evaflex EV250 (Mitsui Dow Polychemicals, MFR: 15g / 10 min) Ultrasen 720 (Tosoh Corporation, MFR: 150g / 10min) Ultrasen 680 (Tosoh Corporation, MFR: 160g / 10min) Ultrasen 681 (Tosoh Corporation, MFR: 350g / 10min) Ultrasen 722 (Tosoh Corporation, MFR: 400g / 10 min)

[0073] Tackifying resin KE-604B (Arakawa Chemical Co., Ltd., acrylic acid modified rosin, softening point: 129°C, acid value: 246 mg KOH / g) Haritac 4821 (Harima Chemicals, maleic acid modified rosin, softening point: 107°C, acid value: 22.5 mg KOH / g) Alcon P-115 (Arakawa Chemical Co., Ltd., fully hydrogenated petroleum hydrocarbon, softening point: 115°C, acid value: none) Crystallex F100 (manufactured by Eastman Chemical Company, copolymer of α-methylstyrene and styrene, softening point 100°C, acid value: none) T-REZ HA85 (ENEOS Corporation, hydrogenated petroleum resin, softening point: 85°C, acid value: none) RHR-301 (manufactured by China Wuzhou Sun Shine Forestry & Chemicals Co., LTD of Guangxi, hydrogenated rosin, softening point: 75℃, acid value: 165mgKOH / g)

[0074] ·wax Hardened palm oil (manufactured by Yokoseki Oil & Fat Industries Co., Ltd., saturated fatty acid triglyceride (hardened palm oil), melting point: 59°C, no hydroxyl groups) Hardened rapeseed oil (manufactured by Yokoseki Oil & Fat Industries Co., Ltd., saturated fatty acid triglyceride (hardened rapeseed oil), melting point: 70°C, no hydroxyl groups) Hardened castor oil (manufactured by Yokoseki Oil & Fat Industries, saturated fatty acid triglyceride (hardened castor oil), melting point: 85°C, contains hydroxyl groups) Hardened soybean oil (manufactured by Yamakei Sangyo Co., Ltd., saturated fatty acid triglyceride (hardened soybean oil), melting point: 68°C, no hydroxyl groups) Hydrogenated rice oil 42 (manufactured by Yamakei Sangyo Co., Ltd., saturated fatty acid triglyceride (hydrogenated rice oil), melting point: 42°C, no hydroxyl groups) Himic 1090 (Nihon Seiro Co., Ltd., microcrystalline wax, melting point: 88°C, no hydroxyl groups)

[0075] Additives IRGANOX1010 (BASF, antioxidant) Silicone KF-96-100CS (Shin-Etsu Chemical Co., Ltd., silicone)

[0076] [Table 1]

[0077] Example 1 Shims were set in the hot melt coating machine (Nordson Hybrid Coat (intermittent surface coating specification)) so that the coating width was 2 mm and the coating interval was 2 mm, and the substrate (coated paper (basis weight: 84.9 g / m)) was coated. 2 The hot melt adhesive of Production Example 1 was applied to the sheet of paper (1) and the sheet of paper (2) to produce a heat-sensitive label (coated paper) of Example 1 in which adhesive sections (A) and uncoated sections (B) were arranged alternately. During coating, the rotation speed was adjusted so that the height (La) of the adhesive sections (A) was 22 μm. The area (Ma) of the adhesive sections (A): the area (Mb) of the uncoated sections (B) was 50:50, and the height (La) of the adhesive sections (A) was 22 μm. Furthermore, the heat-sensitive label (PET) and the heat-sensitive label (synthetic paper) of Example 1 were produced in the same manner except that the substrate was changed to PET (thickness: 25 μm) and synthetic paper Yupo #80 (thickness: 80 μm), respectively.

[0078] [Method for measuring the height of the adhesive joint] Using a shape analysis laser microscope VK-X100 (manufactured by Keyence Corporation) with a 5x objective lens, the step height was measured to determine the height of the bonded portion.

[0079] (Examples 2 to 6, 17 to 20) As shown in Table 2, heat-sensitive labels were produced for each of the three substrates (coated paper, PET, and synthetic paper) in the same manner as in Example 1, except that the type of hot melt adhesive, coating width, coating interval, and height (La) of the adhesive portion (A) were changed.

[0080] (Comparative Example 1) As shown in Table 2, a shim was set in a hot melt coating machine (Nordson Hybrid Coat (intermittent surface coating specification)) and the substrate (coated paper (basis weight: 84.9 g / m 2)) was coated entirely with the hot melt adhesive of Production Example 3 to produce a heat-sensitive label (coated paper) of Comparative Example 1. During coating, the rotation speed was adjusted so that the height (La) of the adhesive part (A) was 40 μm. In addition, a heat-sensitive label (PET) and a heat-sensitive label (synthetic paper) of Comparative Example 1 were produced in the same manner, except that the substrate was changed to PET (thickness: 25 μm) and synthetic paper YUPO #80 (thickness: 80 μm), respectively. In Table 2, "ALL" for the coating width Wa of the adhesive part (A) means that the entire surface was coated.

[0081] Example 7 A shim was set on a hot melt coater (Nordson Hybrid Coat (intermittent surface coating specification)) so that the hot melt adhesive of Production Example 1 and the hot melt adhesive of Production Example 6 could be coated alternately with a coating width of 2 mm, and the hot melt adhesive of Production Example 1 and the hot melt adhesive of Production Example 6 were applied to a substrate (coated paper (basis weight: 84.9 g / m 2 )) to produce a heat-sensitive label (coated paper) of Example 6 in which adhesive sections (A) and adhesive sections (C) were arranged alternately. During coating, the rotation speed was adjusted so that the height (La) of the adhesive section (A) made of the hot melt adhesive of Production Example 1 was 15 μm, and the height (Lc) of the adhesive section (C) made of the hot melt adhesive of Production Example 6 was 3 μm. The area (Ma) of the adhesive section (A): the area (Mb) of the adhesive section (C) was 50:50, the height (La) of the adhesive section (A) was 15 μm, and the height (Lc) of the adhesive section (C) was 3 μm. In addition, the heat-sensitive label (PET) and the heat-sensitive label (synthetic paper) of Example 7 were produced in the same manner except that the substrate was changed to PET (thickness: 25 μm) and synthetic paper Yupo #80 (thickness: 80 μm), respectively.

[0082] (Examples 8 to 13, Comparative Example 2) As shown in Table 2, heat-sensitive labels were produced for each of the three types of substrates (coated paper, PET, and synthetic paper) in the same manner as in Example 7, except that the type of hot melt adhesive was changed.

[0083] Example 14 Shims were set in a hot melt coater (Nordson Hybrid Coat (intermittent surface coating specification)) so that the adhesive (A) made of the hot melt adhesive of Production Example 2 would have a coating width of 0.5 mm, the adhesive (C) made of the hot melt adhesive of Production Example 1 would have a coating width of 4.5 mm, and the adhesive between the adhesives (A) and (C) would be spaced 5 mm apart. The hot melt adhesive of Production Example 2 and the hot melt adhesive of Production Example 1 were then applied to a substrate (coated paper (basis weight: 84.9 g / m 2 )), and the heat-sensitive label of Example 13 was produced in which adhesive sections (A), uncoated sections (B), and adhesive sections (C) were arranged alternately. During coating, the rotation speed was adjusted so that the height (La) of the adhesive section (A) was 30 μm and the height (Lc) of the adhesive section (C) made of the hot melt adhesive of Production Example 1 was 10 μm. The area (Ma) of the adhesive section (A): the area (Mc) of the uncoated section (Mb) + the coated section (C) = 5:95, the height (La) of the adhesive section (A) was 30 μm, and the height (Lc) of the adhesive section (C) was 10 μm. In addition, the heat-sensitive label (PET) and the heat-sensitive label (synthetic paper) of Example 14 were produced in the same manner, except that the substrate was changed to PET (thickness: 25 μm) and synthetic paper Yupo #80 (thickness: 80 μm), respectively.

[0084] (Examples 15-16, Comparative Examples 3-4) As shown in Table 2, heat-sensitive labels were produced for each of the three substrates (coated paper, PET, and synthetic paper) in the same manner as in Example 14, except that the type of hot melt adhesive was changed.

[0085] [Table 2]

[0086] <Evaluation> The heat-sensitive labels obtained above were evaluated for blocking properties, adhesive properties, open time, and jamming properties by the following methods. The evaluation results are shown in Table 3.

[0087] (Blocking property) A heat-sensitive label (coated paper) was cut into a size of 5 cm x 5 cm, and 10 of the cut heat-sensitive labels were stacked together, with a 10 kg weight placed on top and placed in an oven at 50°C. After 24 hours, the labels were removed and peeled off, and the blocking properties were evaluated based on the resistance felt when peeled off, according to the following criteria. ◎: Each sheet can be easily peeled off without any resistance. No blocking. : Excellent 〇: There is a sense of resistance and the sheets can be peeled off one by one. No transfer of hot melt adhesive. 〇: Usable ×: The sheets are tightly adhered and cannot be peeled off one by one, and the substrate is damaged or the hot melt adhesive is transferred, and there is obvious blocking. : Unusable

[0088] (PET adhesiveness) Using a heat sealer (Tester Sangyo Co., Ltd., TP-701-G Heat Seal Tester Thermal Inclination Type), heat-sealing was performed on a 50 μm thick PET film with a coated paper base layer, a PET base layer, and a synthetic paper base layer at a heating temperature of 140°C and a pressure of 0.1 MPa for 1 second. The labels were then stored in a constant temperature and humidity chamber at a temperature of 23°C and a humidity of 65% for at least 24 hours. Using a tensile tester, the labels were peeled off at a speed of 300 mm / min and evaluated according to the following criteria. ◎: Base material destruction or 1.5N / 15mm or more: Excellent ○: 0.8N / 15mm or more, less than 1.5N / 15mm: Usable ×: Less than 0.8N / 15mm: Unusable

[0089] (glass adhesion) Using a heat sealer (Tester Sangyo Co., Ltd., TP-701-G Heat Seal Tester Thermal Inclination Type), a heat-sensitive label with a coated paper substrate layer was heat-sealed to a glass slide at a heating temperature of 140°C and a pressure of 0.1 MPa for 1 second, and then stored in a constant temperature and humidity room at a temperature of 23°C and a humidity of 65% for at least 24 hours. Using a tensile tester, the labels were peeled off at a speed of 300 mm / min and evaluated according to the following criteria. ◎: Base material destruction or 1.5N / 15mm or more: Excellent ○: 0.8N / 15mm or more, less than 1.5N / 15mm: Usable ×: Less than 0.8N / 15mm: Unusable

[0090] (Open time) At room temperature of 23°C, a 15mm x 50mm heat-sensitive label (coated paper) was placed on a hot plate heated to 100°C for 3 seconds, and then removed from the hot plate and left to stand for 1 second. Test piece A and test piece B were then left to stand for 3 seconds. Each test piece was then subjected to a pressure of 2.0kgf / cm between two 300mm wide rolls heated to 40°C. 2 After standing for at least 1 hour in a constant temperature and humidity chamber at a temperature of 23°C and a humidity of 65%, the film was peeled off at a speed of 300 mm / min using a tensile tester and evaluated according to the following criteria. ◎: For both test piece A and test piece B, the area of ​​the substrate that was destroyed was 50% or more of the total area of ​​the test piece. Excellent ○: The area of ​​the substrate broken in test piece A was 50% or more of the total area of ​​the test piece, and the area of ​​the substrate broken in test piece B was less than 50% of the total area of ​​the test piece. Usable ×: The area of ​​the substrate broken was less than 50% of the total area of ​​the test piece in both test piece A and test piece B. Unusable.

[0091] (Jamming) The jamming evaluation was performed using a thermal labeling machine (Koyo Automatic Machinery Co., Ltd., Model LR-400KC). Thermal labels (coated paper) measuring 6 cm wide and 10 cm long were cut for one minute at two label feed speeds: low (40 labels / min) and high (200 labels / min), and the presence or absence of jamming during label cutting was evaluated visually. Jamming refers to poor label transport. ◎: No jamming occurred whether the label supply speed was slow or fast. : Excellent ○: No jamming occurred when the label supply speed was low, but jamming occurred when the label supply speed was high. : Usable ×: Jamming occurred at both low and high label feeding speeds. : Unusable

[0092] [Table 3] [Explanation of symbols]

[0093] 1 Adhesive part (A) 2 Uncoated area (B) 3 Adhesive part (C) 4. Base layer (label base)

Claims

1. A heat-sensitive label comprising a substrate layer and an adhesive layer, wherein the adhesive layer satisfies any one of the following (1) to (3): The relationship between the height (La) of the adhesive portion (A) and the height (Lc) of the adhesive portion (C) is La>Lc, A heat-sensitive label characterized in that the adhesive portions (A) and (C) are made of a hot melt adhesive. (1) It has an adhesive portion (A) and an uncoated portion (B), and Ma:Mb=1:99 to 80:20 (2) Having adhesive parts (A) and adhesive parts (C), Ma:Mc=1:99 to 80:20 (3) Having an adhesive portion (A), an uncoated portion (B), and an adhesive portion (C), Ma:(Mb+Mc)=1:99 to 80:20 Ma: Area of ​​adhesive part (A) per unit area Mb: Area of ​​uncoated portion (B) per unit area Mc: Area of ​​adhesive bond (C) per unit area

2. A heat-sensitive label comprising a substrate layer and an adhesive layer, wherein the adhesive layer satisfies any one of the following (1') to (3'): The relationship between the height (La) of the adhesive portion (A) and the height (Lc) of the adhesive portion (C) is La>Lc, A heat-sensitive label characterized in that the adhesive portions (A) and (C) are made of a hot melt adhesive. (1') Adhesive sections (A) and uncoated sections (B) are arranged alternately, and Ma:Mb=1:99 to 80:20 (2') The adhesive portions (A) and the adhesive portions (C) are alternately arranged, and Ma:Mc=1:99 to 80:20 (3') The adhesive portion (A), the adhesive portion (C), the adhesive portion (A) and the uncoated portion (B) are arranged in this order, and Ma:(Mb+Mc)=1:99 to 80:20

3. 3. The heat-sensitive label according to claim 1, wherein the height (La) of the adhesive portion (A) is 10 to 500 μm.

4. 3. The heat-sensitive label according to claim 1, wherein the substrate is selected from the group consisting of paper, plastic film, and synthetic paper.

5. A container to which the heat-sensitive label according to claim 1 or 2 is attached.

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