Hot melt adhesive, adhesive sheet using the same, and container

Abstract

To provide: a hot melt adhesive which has long open time and is excellent in adhesion and blocking resistance; an adhesive sheet using the hot melt adhesive which prevents jamming and has post printability; and a container.SOLUTION: A hot melt adhesive contains a thermoplastic resin (A), a tackifier resin (B), saturated fatty acid triglyceride (C), and a wax (D), wherein the thermoplastic resin (A) contains at least any one of polyolefin (A1) and an ethylene copolymer (A2) (excluding (A1))SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a hot-melt adhesive. Furthermore, this invention relates to an adhesive sheet using the hot-melt adhesive and a container to which the adhesive sheet is attached. [Background technology]

[0002] Hot melt adhesives are solvent-free, making them environmentally friendly and suitable for both the natural environment and the work environment. Furthermore, since it hardens immediately after being coated onto film and paper substrates after heating and melting, it can be wound up quickly, resulting in a compact coating machine. In addition, because it hardens and adheres immediately when substrates are bonded together while heated and molten, it also functions as an instant adhesive, offering many advantages.

[0003] While adhesive labels are commonly used for glass and plastic bottles, the release liner (film) generates waste, making them unsuitable for waste reduction. Therefore, thermal labels have attracted attention as an adhesive-free alternative. Hot-melt adhesives were developed as thermal label adhesives that do not use dicyclohexyl phthalate (DCHP), which is suspected to be an endocrine disruptor, as a solid plasticizer (Patent Document 1). However, they had the problem of not adhering stably to containers due to their short open time. Furthermore, problems arose such as adhesive sticking to the labeler's cutter during labeling, causing jamming, and when hot-melt adhesive was applied and stored in a roll before printing, a small amount of hot-melt adhesive components adhered to the printed surface, resulting in poor ink adhesion (poor printability). As a result, they did not become widespread. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-137438 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Hot-melt adhesives for thermal labels have the advantage of being environmentally friendly. However, as mentioned above, hot-melt adhesives have drawbacks such as a short open time, unstable adhesion during labeling, jamming, and poor suitability for post-printing.

[0006] The object of the present invention is to provide a hot melt adhesive with a long open time and excellent adhesion and blocking resistance, and an adhesive sheet and container suitable for thermal labels using the hot melt adhesive, which does not cause jamming and is suitable for post-printing. [Means for solving the problem]

[0007] This disclosure relates to the following hot melt adhesives, adhesive sheets using the same, and containers.

[0008] [1] A hot melt adhesive comprising a thermoplastic resin (A), a tackifying resin (B), a saturated fatty acid triglyceride (C), and a wax (D), wherein the thermoplastic resin (A) comprises at least one of polyolefins (A1) and ethylene copolymers (A2) (excluding (A1)).

[0009] [2] The hot melt adhesive according to [1], characterized in that the tackifying resin (B) is at least one selected from the group consisting of rosin-based tackifying resins, terpene-based tackifying resins, and petroleum-based tackifying resins.

[0010] [3] The hot melt adhesive according to [1] or [2], characterized in that the melting point of saturated fatty acid triglyceride (C) is 50°C or higher and 100°C or lower.

[0011] [4] A hot melt adhesive according to any one of [1] to [3], characterized in that, of 100% by mass of the total of thermoplastic resin (A), tackifying resin (B), saturated fatty acid triglyceride (C), and wax (D), the content of thermoplastic resin (A) is 10 to 70% by mass, the content of tackifying resin (B) is 10 to 70% by mass, the content of saturated fatty acid triglyceride (C) is 10 to 70% by mass, and the content of wax (D) is 10 to 70% by mass.

[0012] An adhesive sheet characterized by having an adhesive layer made of a hot melt adhesive as described in any of [5][1] to [4].

[0013] A container to which the adhesive sheet described in [6][5] has been attached. [Effects of the Invention]

[0014] This disclosure provides excellent advantages, including a hot-melt adhesive with a long open time, superior adhesion and blocking resistance, and adhesive sheets and containers using the hot-melt adhesive that do not cause jamming and are suitable for post-printing. [Modes for carrying out the invention]

[0015] 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, insofar as they are consistent with the spirit of the invention. In this specification, "hot melt" refers to a material that is solid or viscous at room temperature and melts into a fluid or liquid state upon heating. Furthermore, numerical ranges specified using "~" in this specification include the numerical values ​​before and after "~" as the lower and upper limits. In addition, unless otherwise noted, each component mentioned in this specification may be used independently or in combination of two or more.

[0016] As used herein, the "melting point of saturated fatty acid triglyceride (C)" can be measured by the melting point measurement method described in the Japanese Standards of Food Additives (8th edition). The melting point of wax is measured in accordance with JIS K2235 5.3. The melting point of the thermoplastic resin is measured in accordance with JIS K6924-2 (DSC method). Melt mass flow rate (hereinafter also referred to as "MFR") is one of the indicators showing the fluidity of a resin in a molten state, and is a value measured under the conditions of 190°C and 21.168N in accordance with JIS K7210.

[0017] The hot-melt adhesive of the present disclosure is suitable for use in adhesive sheets for heat-sensitive labels and containers to which the adhesive sheet is attached, but can be used for any applications.

[0018] <<Hot-Melt Adhesive>>

[0019] The hot-melt adhesive of the present invention comprises a thermoplastic resin (A), a tackifier resin (B), a saturated fatty acid triglyceride (C), and a wax (D). Based on 100% by mass in total of the thermoplastic resin (A), the tackifier resin (B), the saturated fatty acid triglyceride (C) and the wax (D), it is preferable that the content of the thermoplastic resin (A) is 10 to 70% by mass, the content of the tackifier resin (B) is 10 to 70% by mass, the content of the saturated fatty acid triglyceride (C) is 10 to 70% by mass, and the content of the wax (D) is 10 to 70% by mass. Setting the content of the thermoplastic resin (A) to 10 to 70% by mass maintains good adhesion (cohesion); setting the content of the tackifier resin (B) to 10 to 70% by mass maintains good adhesion (adhesion); setting the content of the unsaturated and saturated fatty acid triglyceride (C) to 10 to 70% by mass maintains good open time and blocking resistance; and setting the content of the wax (D) to 10 to 70% by mass improves post-printing applicability.

[0020] <Thermoplastic Resin (A)> The term "thermoplastic resin" refers to a resin that has the property of being melt-moldable upon heating. The thermoplastic resin (A) constituting the hot-melt adhesive of the present invention refers to one having a viscosity at 190°C of 100 mPa·s or more. The thermoplastic resin includes at least one of a polyolefin (A1) and an ethylene copolymer (A2) (excluding (A1)).

[0021] Specific examples of the polyolefin (A1) include polyethylene, polypropylene, poly-1-butene, polyisobutylene, polymethylpentene, propylene-ethylene copolymers, ethylene-propylene-diene copolymers, ethylene / 1-butene copolymers, and ethylene / octene copolymers.

[0022] Specific examples of the ethylene copolymer (A2) include ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl acetate-vinyl chloride copolymer, ethylene-vinyl acetate-vinyl chloride-maleic acid copolymer, ethylene-methyl (meth)acrylate copolymer, ethylene-ethyl (meth)acrylate copolymer, ethylene-butyl (meth)acrylate copolymer, ethylene-2-ethylhexyl (meth)acrylate copolymer, ethylene-dodecyl (meth)acrylate, ethylene-(meth)acrylic acid copolymer, and ethylene-maleic acid copolymer. Ethylene-vinyl acetate copolymer (EVA) is preferred.

[0023] In addition to the thermoplastic resin (A) used in the present invention, a thermoplastic resin other than the polyolefin (A1) and the ethylene copolymer (A2) can be used in combination. Examples of thermoplastic resins other than (A1) and (A2) include polyamide, polyester, polyurethane, and acrylic resin. <Tackifying resin (B)> The tackifying resin (B) constituting the hot melt adhesive of the present invention is not particularly limited, but examples include phenol resins, modified phenol resins, terpene phenol resins, xylene phenol resins, cyclopentadiene-phenol resins, xylene resins, aliphatic, alicyclic, aromatic petroleum resins, hydrogenated aliphatic, alicyclic, 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 adhesion and blocking resistance, 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.

[0024] When the label substrate is glass or metal container, a tackifier having a polar group such as a carboxylic acid is suitable from the viewpoint of adhesion. When the acid value of the tackifier is 50 mg KOH / g or more and 300 mg KOH / g or less, more preferably 150 mg KOH / g or more and 250 mg KOH / g or less, compatibility of the hot melt adhesive and adhesion to glass and metal can be obtained.

[0025] <Saturated fatty acid triglycerides (C)> Generally, saturated fatty acid triglycerides refer to oils and fats that are liquid at room temperature because they contain a large amount of unsaturated fatty acid triglycerides with relatively low melting points. Hydrogenation is then performed to increase the proportion of saturated fatty acid triglycerides, which have higher melting points, resulting in oils and fats that are solid at room temperature. Typical oils and fats 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. The hardened oils (hydrogenated products) of these oils are examples of saturated fatty acid triglycerides (C) in this invention.

[0026] Before hardening, the oil consists of a mixture of fatty acid triglycerides with 6 to 22 carbon atoms, and hardens upon hydrogenation, increasing its melting point. The melting point of the saturated fatty acid triglyceride (C) used in this invention is preferably 50°C to 100°C, and more preferably 65°C to 90°C. A melting point of saturated fatty acid triglyceride (C) of 50°C to 100°C provides good blocking resistance and long open time performance.

[0027] In saturated fatty acid triglycerides (C), it is preferable that the saturated fatty acid does not have a hydroxyl group. While the presence of a hydroxyl group increases the open time, it can result in poorer blocking resistance.

[0028] <Wax (D)> Wax (D) plays a role in improving the blocking resistance of the hot melt adhesive and the printability of thermal labels using the hot melt adhesive. The wax (D) constituting the hot melt adhesive of the present invention refers to a wax with a viscosity of less than 100 mPa·s at 190°C. Examples of waxes include carnauba wax, candelilla wax, montan wax, paraffin wax, microwax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, or oxides of these waxes, ethylene-acrylic acid copolymer wax, ethylene-methacrylic acid copolymer wax, etc.

[0029] The melting point of wax (D) is preferably between 65°C and 140°C. A melting point of 65°C to 130°C of wax provides good post-printability and blocking resistance.

[0030] The hot-melt adhesive of the present invention may further contain other components as long as they do not impair the effects of the present invention. Examples of other components include colorants, anti-blocking agents, inorganic fillers, antioxidants, fillers, flame retardants, plasticizers, antistatic agents, light stabilizers, ultraviolet absorbers, and heavy metal deactivators. These components can be used individually or in combination of two or more.

[0031] The coloring agent can be any conventionally known coloring agent such as red, blue, green, or yellow. The coloring agent can be a pigment, dye, or pigment, and examples include monoazo, disazo, azo lake, benzimidazolon, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, quinacridone, phthalocyanine, and anthraquinone. Pigment types include pigments, perylene, monoazo, condensed azo, isoindolinone, titanium dioxide, and carbon.

[0032] Examples of the aforementioned blocking inhibitors include silicones, stearate amides, oleate amides, erucate amides, oleamides, and unsaturated fatty acid amides such as behenate amide.

[0033] Examples of the inorganic fillers include metals, metal oxides, and metal hydroxides in granular or fibrous form. Specifically, examples include glass fibers, carbon fibers, calcium silicate, calcium titanate, aluminum borate fibers, flake glass, talc, kaolin, mica, hydrotalcite, calcium carbonate, zinc carbonate, zinc oxide, monocalcium phosphate, wollastonite, silica, zeolite, alumina, boehmite, aluminum hydroxide, titanium dioxide, silicon dioxide, magnesium oxide, calcium silicate, sodium alumina silicate, magnesium silicate, carbon nanotubes, graphite, copper, silver, aluminum, nickel, iron, calcium fluoride, mica, montmorillonite, and apatite.

[0034] The aforementioned antioxidants 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, polymers of 2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, nickel dibutyldithiocarbamate, 1-oxy-3-methyl-4-isopropylbenzene, 4,4'-butylidenebis-(3-methyl-6-ter-butylphenol), and 2-mercaptobenzimidazole. Antioxidants can be used to prevent thermal degradation and thermal decomposition.

[0035] Examples of the aforementioned fillers include wet silica, aluminum hydroxide, aluminum oxide, magnesium oxide, montmorillonite, mica, smectite, organic montmorillonite, organic mica, and organic smectite.

[0036] Examples of the aforementioned flame retardants include phosphorus-containing compound flame retardants, halogen-containing compound flame retardants, sulfonic acid metal salt flame retardants, and silicon-containing compound flame retardants.

[0037] Examples of the aforementioned plasticizers include phthalate ester plasticizers, polyester plasticizers, aliphatic dibasic acid ester plasticizers, aliphatic monobasic acid ester plasticizers, phosphate ester plasticizers, citrate ester plasticizers, epoxy plasticizers, trimellitic acid ester plasticizers, tetrahydrophthalate ester plasticizers, glycol plasticizers, and bisphenol A alkylene oxide derivatives.

[0038] The aforementioned antistatic agent may be one that is commonly used as an antistatic agent for plastics, and specifically includes 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., alkylbenzene sulfonates, higher alcohol sulfate salts), cationic surfactants (e.g., aliphatic amine salts, quaternary ammonium salts), and amphoteric surfactants (e.g., imidazoline type, betaine type).

[0039] Examples of the aforementioned light stabilizers include hindered amine compounds and benzoate compounds.

[0040] Examples of the aforementioned ultraviolet absorbers include benzophenone-based ultraviolet absorbers, triazine-based ultraviolet absorbers, and benzotriazole-based ultraviolet absorbers.

[0041] Examples of the heavy metal deactivators include salicylic acid derivatives, hydrazide derivatives, or oxalamide derivatives.

[0042] The content of components other than thermoplastic resin (A), tackifier (B), saturated fatty acid triglyceride (C), and wax (D) is preferably 0 to 40% by mass per 100% by mass of the hot melt adhesive. More preferably 0 to 30% by mass, and even more preferably 0 to 20% by mass.

[0043] ≪Manufacturing of hot melt adhesives≫ The hot melt adhesive of the present invention can be manufactured, for example, by melting saturated fatty acid triglyceride (C) and wax (D) in a melting vessel equipped with a stirrer, mixing and dispersing a thermoplastic resin (A) in the mixture, and then adding and mixing a tackifying resin (B) after the thermoplastic resin (A) has dissolved. Alternatively, the hot melt adhesive of the present invention may be manufactured by mixing and dispersing the components in an extruder and extruding the molten mixture from a nozzle at the tip of the extruder.

[0044] The hot-melt adhesive of the present invention may be used by mixing the constituent components and molding them into a desired shape. Examples of desired shapes include granules, pellets, planar shapes, or block shapes. These methods can be carried out without limitation using known methods.

[0045] Adhesive Sheet The adhesive sheet of the present invention has an adhesive layer made of the hot melt adhesive described above. The adhesive layer may be provided on the substrate, or there may be an intermediate layer such as an ink layer between the substrate and the hot melt adhesive.

[0046] Examples of substrates include plastics, synthetic paper, paper, and metal containers.

[0047] Adhesive sheets can be manufactured by known methods. For example, they can be manufactured by applying a hot-melt adhesive to a substrate and then cooling it. One example of a method for applying hot-melt adhesive to a substrate is to heat it to liquefy it and then form it in layers 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 coatings. After coating, an organic solvent may be added to adjust the viscosity by cooling. If an organic solvent is used, it may be removed in a hot-air drying oven.

[0048] The coating amount of the adhesive sheet of the present invention is 7-15 g / m². 2 It is preferable. Coating amount: 7-15 g / m 2 As a result, it is possible to improve adhesion to glass bottles and plastic bottles, water resistance, and condensation resistance, as well as suppress jamming and blocking of the adhesive sheet in the label cutter blade.

[0049] The adhesive sheet of the present invention has excellent suitability for post-printing.

[0050] ≪Container with adhesive sheet attached≫ The container to which the adhesive sheet of the present invention is attached is a container made of glass, ceramic, plastic, or metal. Methods for attaching the adhesive sheet include heating the adhesive sheet and attaching it to the bottle, or, when in-mold molding plastic containers, setting the label in the mold beforehand and using the heat generated during the molding process to adhere it to the container. The glass bottle, which is one of the containers of the present invention, may be a clear bottle, a brown bottle, or a colored bottle such as blue, red, or green. The surface of the glass bottle may be untreated or coated with a resin such as cold coating, hot coating, or polyethylene (PE) coating. The thermal 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.

[0051] When the adherend is a glass bottle, it is desirable that the acid value of the hot melt adhesive be 50 mg KOH / g or higher, preferably 70 mg KOH / g or higher. An acid value of 50 mg KOH / g in the hot melt adhesive provides both adhesion to glass and water resistance.

[0052] As a plastic container for the present invention, any material that can be used as a container on its own can be used, such as olefins like high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polypropylene, as well as polystyrene, polyester (such as polyethylene terephthalate), polycarbonate, and vinyl chloride. Furthermore, if a multilayer structure is possible, a foamed layer may be placed on one side of the container to improve the impact strength of the container, and the same resin may be extruded without foaming to create a multilayer container. In-mold molding methods include vacuum forming, pressure forming, extrusion blow molding, injection molding, injection blow molding, and biaxial stretch blow molding.

[0053] In vacuum forming, pressure forming, extrusion blow molding, injection molding, injection blow molding, biaxial stretch blow molding, etc., when applying labels to the outer surface of resin containers, such as polyolefin containers and polyethylene terephthalate containers, an in-mold labeling method is known in which an in-mold label is pre-placed on the cavity surface of the molding die, and the in-mold label is heat-fused to the outer surface of the container at the same time as the container is molded. This in-mold labeling method has the advantage that the in-mold label can be adhered to the entire outer surface of the container, making it difficult for the label to peel off the container and facilitating large-area labeling. Furthermore, it is preferable to use this method because it can increase the rigidity of the container, allow for thinner containers, offer excellent design, and enable labor and space savings in the process.

[0054] These application methods allow for the application of adhesive sheets with a hot-melt adhesive layer (which is not tacky at room temperature) to the substrate while heating, eliminating the need for release paper, preventing contamination of the application machine, facilitating easy label alignment, preventing blocking during normal transport and handling, and reducing waste by eliminating the need for release paper, resulting in an environmentally friendly label.

[0055] By using the hot-melt adhesive of the present invention, the performance of adhesive sheets with a long open time and good blocking resistance can be significantly improved. This is because, when the adhesive sheet is heated and bonded to the substrate, the long open time of the hot-melt adhesive allows for easy bonding to the substrate even if the heat from the hot-melt adhesive is absorbed by the substrate. On the other hand, when storing adhesive sheets, hot-melt adhesives with a long open time generally have poor blocking resistance, leading to problems such as labels sticking together or the surface printing peeling off. [Examples]

[0056] Next, the present invention will be described based on specific embodiments in comparison with comparative examples, but the present invention is not limited to these. Unless otherwise specified, "parts" and "%" in the embodiments refer to "parts by mass" and "mass%", respectively.

[0057] [Viscosity at 190°C] Viscosity measurement at 190°C was performed by pouring 500 cm³ of hot melt adhesive. 3 300g was placed in a metal can (diameter: approximately 85mm), heated to 200°C, and then gradually cooled. The viscosity at 190°C was measured using a B-type rotational viscometer. Rotor 2 or 3 was used, and measurements were taken at rotational speeds of 6, 12, 30, or 60 rpm. If the viscosity measured at rotor 3 at 6 rpm was 10,000 mPa·s or higher, it was considered to be 10,000 rpm or higher. If the viscosity measured at rotor 2 at 60 rpm was less than 100 mPa·s, it was considered to be less than 100 mPa·s.

[0058] The raw materials used in the hot melt adhesives of the examples and comparative examples are shown below.

[0059] Thermoplastic resin (A ) (A1) Polyolefin A1-1: REXtac 2535 (manufactured by REXtac, ethylene-propylene copolymer, acid value: 0 mg KOH / g, viscosity at 190°C: 3500 mPa·s) A1-2: REXtac 2715A (manufactured by REXtac, butene-propylene copolymer, acid value: 0 mg KOH / g, viscosity at 190°C: 1500 mPa·s) A1-3: REXtac RT2104 (manufactured by REXtac, ethylene homopolymer, acid value: 0 mg KOH / g, viscosity at 190°C: 400 mPa·s) (A2) Ethylene copolymer A2-1 UltraCen 720 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content 28% by mass, melting point: 69°C, viscosity at 190°C: 10,000 mPa·s or higher) A2-2 UltraCen 722 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content 28% by mass, melting point: 65°C, viscosity at 190°C: 10,000 mPa·s or higher) A2-3: UltraCen 633 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content 20% by mass, melting point: 81°C, viscosity at 190°C: 10,000 mPa·s or higher) A2-4: UltraCen 680 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content 20% by mass, melting point: 78°C, viscosity at 190°C: 10,000 mPa·s or higher) A2-5: UltraCen 681 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content 20% by mass, melting point: 76°C, viscosity at 190°C: 10,000 mPa·s or higher) A2-6: UltraCen 685 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content 14% by mass, melting point: 77°C, viscosity at 190°C: 10,000 mPa·s or higher) A2-7 UltraCen 530 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content 6% by mass, melting point: 64°C, viscosity at 190°C: 10,000 mPa·s or higher) A2-8: Rexpearl EB440H (manufactured by Nippon Polyethylene Co., Ltd., ethylene-ethyl acrylate copolymer, ethylene content 80% by mass, melting point: 77°C, viscosity at 190°C: 10,000 mPa·s or higher) A2-9 Primacol 5980I (manufactured by SK General Chemical Co., Ltd., ethylene-acrylic acid copolymer, acrylic acid content 20% by mass, melting point: 75°C, acid value: 155 mgKOH / g, viscosity at 190°C: 10,000 mPa·s or higher) Tackifying resin (B) B-1 Pine Crystal KE-604 (manufactured by Arakawa Chemical Co., Ltd., acrylic acid-modified hydrogenated rosin, softening point: 129°C, acid value: 230 mg KOH / g) B-2 KE-604B (manufactured by Arakawa Chemical Co., Ltd., acrylic acid modified rosin, softening point: 129°C, acid value: 246 mg KOH / g) B-3 RHR-301 (manufactured by Maruzen Oil & Chemical Trading Co., Ltd., hydrogenated rosin, softening point: 80°C, acid value: 170, mgKOH / g) B-4 Alcon M-100 (manufactured by Arakawa Chemical Co., Ltd., fully hydrogenated petroleum hydrocarbon, softening point: 100℃) B-5 Crystalex F100 (manufactured by Eastman Chemical Company, α-methylstyrene, softening point 100°C) B-6 Silveres TR7125 (manufactured by Kraton, terpene, softening point 116°C) Saturated fatty acid triglycerides (C) C-1 Palm oil (manufactured by Yokozeki Oil & Fat Industry Co., Ltd., melting point: 59℃) C-2 Rapeseed oil (manufactured by Yokozeki Oil & Fat Industry Co., Ltd., melting point: 70℃) C-3 Castor Oil (Super Hardened) (Manufactured by Yokozeki Oil & Fat Industry Co., Ltd. Melting point: 85℃) C-4 Soybean Hydrogenated Oil (Manufactured by Yamakei Sangyo Co., Ltd. Melting point: 68℃)

[0060] Wax (D) D-1 Paraffin Wax NHP-11 (Manufactured by Nippon Seiro Co., Ltd. Melting point: 68℃, Viscosity at 190℃: less than 100 mPa·s) D-2 Paraffin Wax NHP-9 (Manufactured by Nippon Seiro Co., Ltd. Melting point: 72℃, Viscosity at 190℃: less than 100 mPa·s) D-3 Sasol C-80 (manufactured by Sasol Chemical Industries Limited; melting point: 82°C, viscosity at 190°C: less than 100 mPa·s) D-4 Polywax 2000 (Melting point: 126°C, Viscosity at 190°C: less than 100 mPa·s) D-5 KH Paraffin FRPW F60L (King Honor Co., Ltd. Melting point: 61°C, Viscosity at 190°C: less than 100 mPa·s) D-6 High Wax NP055 (manufactured by Mitsui Chemicals, Inc. Melting point: 136℃, Viscosity at 190℃: less than 100 mPa·s)

[0061] Additive (E) E-1 Antioxidant: IRGANOX1010 (manufactured by BASF) E-2 Blocking inhibitor: Amid E (manufactured by Kao Corporation, erucate amide) E-3 Blocking inhibitor: Fatty acid amide S (manufactured by Kao Corporation, stearate amide) E-4 Silicone KF96 100CS (manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity: 100 mmHg) 2 / s)

[0062] Unsaturated fatty acid triglycerides (F) F-1 (Unhydrogenated, Unhardened) Oils and Fats: Palm Oil (Manufactured by Kaneda Co., Ltd., Melting Point 37°C)

[0063] In this specification, "acid value" was measured in accordance with K-0070-1992, "Test methods for acid value, saponification value, ester value, iodine value, hydroxyl value, and unsaponifiable matter of chemicals."

[0064] (Example 1: Preparation of hot melt adhesive) 20 parts of (B-5) as a tackifying resin, 20 parts of (C-1) as a saturated fatty acid triglyceride, 20 parts of wax (D-1), and 0.1 parts of antioxidant (E-1) were heated and melted at 180°C. Then, while stirring with a stirrer, 40 parts of thermoplastic resin (A1-1) were gradually added. The thermoplastic resin was completely dissolved to obtain the hot melt adhesive of Example 1.

[0065] (Examples 2-15) Hot melt adhesives for Examples 2 to 15 were obtained in the same manner as in Example 1, except that the materials and their proportions were changed as shown in Tables 1 and 2. When an anti-blocking agent was included, it was added at the same time as saturated fatty acid triglyceride (C).

[0066] (Comparative Examples 1-3) Hot melt adhesives for Comparative Examples 1 to 3 were obtained in the same manner as in Example 1, except that the materials and their proportions were changed as shown in Table 3.

[0067] (Manufacturing of thermal labels) Using a GPD300E manufactured by Yuri Roll Machinery Co., Ltd., hot melt adhesives from Examples 1-15 and Comparative Examples 1-3 were applied to double-sided art paper (without printing) at a constant coating thickness to produce thermal labels. The coating conditions are as follows: Coating speed: 5m / min Coating thickness: 8-12 μm Hopper temperature: 150~180℃ Base material: Double-sided art paper (Basis weight: approx. 90g / m²) 2 )

[0068] Evaluation of adhesion Adhesion was evaluated using PET (thickness: 500 μm) and PP (thickness: 500 μm) as substrates, and the best evaluation result was adopted. Using a heat sealing machine (Tester Industries Co., Ltd., TP-701-G Heat Seal Tester, Thermal Gradient Type), the coating amount was 12 g / cm². 2 The thermal labels and substrates were heat-sealed at a temperature of 140°C, a pressure of 0.1 MPa, and a second, and then stored for more than 24 hours in a constant temperature and humidity chamber at 23°C and 65% humidity. Evaluation was performed by peeling the samples off a tensile testing machine at a speed of 300 mm / min, according to the following criteria. ◎: Substrate destruction: Good ○: Cohesion Breakdown: Usable ×: Interfacial peeling: Not usable

[0069] Evaluation of Open Time Using an adhesive strength measuring device (Type ASM-15N, manufactured by JT Toshi Co., Ltd.), hot melt adhesive was applied to corrugated cardboard (B-flute corrugated cardboard) at a rate of 36 cm². 3 After coating at a coating speed of 30 m / min, the corrugated cardboard (B-flute corrugated cardboard) is bonded with an adhesive pressure of 1.6 g / cm². 2 The two pieces were bonded together using [a specific method]. After bonding for 120 seconds, the shortest bonding time at which more than 80% of the paper tore when peeled off was defined as the open time. ◎: Longer than 20 seconds: Good 〇: 15 seconds or more and 20 seconds or less: Can be used ×: Less than 15 seconds: Not usable

[0070] Evaluation of blocking resistance The measurement method for the blocking resistance evaluation is as follows: A heat-sensitive label (double-sided art paper, unprinted) was subjected to a load of 500 g / cm² and stored in an oven at 50°C. After 24 hours, the label was taken out and peeled, and the blocking resistance was evaluated based on the resistance felt during peeling according to the following criteria. ◎: No blocking occurs, and each sheet can be peeled off easily: Good ○: Slight blocking occurs, but each sheet can be peeled off: Usable ×: Complete blocking occurs, and each sheet cannot be peeled off: Unusable

[0071] Post-printability The post-printability evaluation was performed as follows: A heat-sensitive label (double-sided art paper, unprinted) was applied with a load of 500 g / cm 2 , left to stand in an oven at 50°C for 24 hours, stored in a constant temperature and humidity chamber at a temperature of 23°C and a relative humidity of 50% for 1 hour or more, and then the surface wettability of the printing surface of the heat-sensitive label was measured. The measurement was carried out using wettability test pens (Tension Checker, manufactured by Daiko Seisakusho Co., Ltd., dyne levels: 30, 34). The pen tip of the test pen was applied horizontally to the printing surface and moved slowly to coat the surface. If the ink was retained after 2 seconds, it was determined that the surface wettability was equal to or higher than the dyne level of the pen; if the ink formed water droplets or the coated area shrank, it was determined that the surface wettability was lower than the dyne level of the pen. The evaluation criteria are as follows. ◎: 34 mN / m or higher: Good ○: 30 mN / m or higher and 34 mN / m or lower: Usable ×: Lower than 30 mN / m: Unusable

[0072] Evaluation of jamming properties The jamming property evaluation was performed using a heat-sensitive labeler (manufactured by Koyo Automation Co., Ltd., model: LR-400KC). Labels with a width of 6 cm were cut into a length of 10 cm at a label feeding speed of 350 sheets / min for 5 minutes, and the presence or absence of jamming during label cutting was visually evaluated. ◎: No jamming occurred: Good ×: Jamming occurred: Unusable

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3]

[0076] Comparative Example 1, which did not contain fatty acid triglycerides, had a short open time and problems with adhesion (PET, PE). Comparative Example 2, which did not contain wax, had problems with post-printability because the fatty acid triglyceride components transferred to the surface of the substrate (art paper) in very small amounts. Comparative Example 3, which used unsaturated saturated fatty acid triglycerides instead of saturated fatty acid triglycerides, had problems with open time, blocking properties, and jamming properties.

Claims

1. Thermoplastic resin (A), tackifying resin (B), saturated fatty acid triglyceride (C), and Contains wax (D), The thermoplastic resin (A) comprises only ethylene-(meth)acrylic acid copolymer or ethylene-vinyl acetate copolymer. The tackifying resin (B) is a rosin-based tackifying resin with an acid value of 150 to 250 mg KOH / g. Wax (D) is a paraffinic wax or a polyethylene wax. A hot melt adhesive characterized in that, in a total of 100% by mass of thermoplastic resin (A), tackifying resin (B), saturated fatty acid triglyceride (C), and wax (D), the content of thermoplastic resin (A) is 20 to 40% by mass, the content of tackifying resin (B) is 10 to 20% by mass, the content of saturated fatty acid triglyceride (C) is 20 to 60% by mass, and the content of wax (D) is 10 to 40% by mass.

2. The hot melt adhesive according to claim 1, characterized in that the melting point of saturated fatty acid triglyceride (C) is 50°C or higher and 100°C or lower.

3. An adhesive sheet characterized by having an adhesive layer made of the hot melt adhesive described in claim 1 or 2.

4. A container to which the adhesive sheet described in claim 3 is attached.

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