Hot-melt adhesive, lid material using the same and member set for sealing container

Abstract

To provide a hot-melt adhesive which has good basic performances (coating suitability, blocking resistance, and low temperature heat sealability) of the hot-melt adhesive, has such heat resistance as to prevent seal peeling even under high temperature environment, prevents zipping when being peeled, and exhibits stable seal strength and excellent peeling appearance, and a lid material using the composition.SOLUTION: A hot-melt adhesive contains, in 100 mass% of a hot-melt adhesive, 20 to 50 mass% of (A) an ethylene-vinyl acetate copolymer having a melt mass flow rate at 190°C and a load of 2.16 kg of 3 to 400 g / 10 min, 10 to 30 mass% of (B) a tackifier resin having a softening point of 90 to 150°C, 20 to 50 mass% of (C) a wax having a melting point of 60°C or higher and lower than 120°C, 5 to 25 mass% of (D) talc, and 0.1 to 2.0 mass% of (E) silicone oil.SELECTED DRAWING: None

Description

Technical Field

[0001] In addition to having good coating applicability, blocking resistance, and low-temperature heat sealability, the present invention has heat resistance such that seal peeling does not occur even in a high-temperature environment, and has no dipping during peeling, and exhibits stable seal strength and excellent peel appearance. The present invention relates to a hot melt adhesive, a lid material using the same, and a member set for a sealed container.

Background Art

[0002] In the field of article packaging, in order to protect and preserve the contents, a method of adhering a lid material to the opening of a container through a heat-sealing layer having excellent sealing properties is used.

[0003] As a method of sealing a container obtained by vacuum molding a thermoplastic resin sheet such as high-impact polystyrene, polypropylene, polyethylene terephthalate (PET ) with a sheet such as an aluminum foil, polypropylene, polyvinyl chloride, polyethylene terephthalate, or a lid material formed therefrom, a sheet material laminated with a low-melting-point resin such as low-density polyethylene, low-molecular-weight polyester, or ethylene-unsaturated ester copolymer is used on the adhesive surface of the lid material, or a method of previously applying a hot melt adhesive only to the seal portion is adopted.

[0004] Among them, hot melt adhesives used for sealing food containers require not only basic properties such as coating applicability, airtightness, water resistance, oil resistance, alkali resistance, non-toxicity, and blocking resistance, which are required for general hot melt adhesives intended only for adhesion, but also the following special qualities.

[0005] · There is no dipping (a phenomenon accompanied by a strong resistance feeling and sound) during peeling, and the peeling feeling is good. Smooth and uniform peeling can be achieved so that the contents do not spill or scatter. · It is easy to adjust the adhesive strength. The adhesive strength (opening strength) that allows easy opening can be set to 10 N to 15 N (easy opening property). · No peeling of the seal occurs during storage and transportation in a high-temperature environment (heat resistance). · It can adhere even when heat is taken away from the contents adhering to the container flange part and the heat seal temperature drops (low-temperature heat sealability).

[0006] Among these, in order to suppress dipping during peeling, a method of causing cohesive failure in the hot melt layer rather than interfacial peeling between the hot melt layer and the container is used. As a method of causing cohesive failure, a method of reducing the cohesive force of the hot melt adhesive by adding a low-molecular-weight resin or mixing resins with low compatibility as disclosed in Patent Document 1 is disclosed. However, these methods have a problem that the heat resistance is impaired as the cohesive force decreases. Further, Patent Document 2 discloses a method of adding an inorganic filler such as talc, but when used in a hot melt adhesive, if the addition amount of talc is small, cohesive failure does not occur, and when the addition amount of talc is increased until cohesive failure occurs, the adhesive strength and heat resistance are significantly reduced. Therefore, with the methods described in Patent Documents 1 to 2, it is difficult to achieve both suppression of dipping due to cohesive failure and heat resistance.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to provide a hot melt adhesive that has good basic performance (coating suitability, blocking resistance, and low-temperature heat sealability) of the hot melt adhesive, has heat resistance in which seal peeling does not occur even in a high-temperature environment, has no dipping during peeling, and exhibits stable seal strength and excellent peel appearance.

Means for Solving the Problem

[0009] As a result of intensive studies by the present inventors, it has been found that the above problems can be solved by a specific hot melt adhesive defined below, and the present invention has been completed.

[0010] The hot melt adhesive according to one aspect of the present invention contains, in 100% by mass of the hot melt adhesive, 20 to 50% by mass of an ethylene-vinyl acetate copolymer (A) having a melt mass flow rate of 3 to 400 g / 10 min at 190°C and a load of 2.16 kg, 10 to 30% by mass of a tackifying resin (B) having a softening point of 90 to 150°C, 20 to 50% by mass of a wax (C) having a melting point of 60 to 120°C, 5 to 25% by mass of talc (D), and 0.1 to 2.0% by mass of silicone oil (E).

[0011] The hot melt adhesive according to one aspect of the present invention is characterized in that, in 100% by mass of the wax (C), it contains 50% by mass or more of a wax (C1) having a melting point of 60 to 100°C and satisfying the following formula. (Formula) 5°C ≤ Y - X ≤ 30°C X: Onset temperature of the endothermic peak in the DSC curve obtained by differential scanning calorimetry (DSC) measurement Y: Endset temperature of the endothermic peak in the DSC curve obtained by differential scanning calorimetry (DSC) measurement

[0012] The hot melt adhesive according to one aspect of the present invention is characterized in that the tackifying resin (B) contains a petroleum resin and / or a terpene resin.

[0013] The hot melt adhesive according to one aspect of the present invention is characterized in that the kinematic viscosity of the silicone oil (E) at 25°C is 50 to 10,000 mm 2 / s.

[0014] The hot-melt adhesive according to one aspect of the present invention is characterized in that the vinyl acetate content of the ethylene-vinyl acetate copolymer (A) is in the range of 20 to 35% by mass.

[0015] The lid material according to one aspect of the present invention is characterized in that it comprises a hot-melt layer made of the above-described hot-melt adhesive on one side of a base material in which at least two or more selected from the group consisting of a resin sheet, paper, and an aluminum sheet are laminated.

[0016] The member set for an openable sealed container according to one aspect of the present invention is characterized by comprising a container and the above-described lid material.

Effects of the Invention

[0017] According to the present invention, in addition to the good basic performance (coating suitability, blocking resistance, and low-temperature heat sealability) of the hot-melt adhesive, it has heat resistance such that seal peeling does not occur even in a high-temperature environment, and there is no dipping during peeling, and a hot-melt adhesive showing stable seal strength and excellent peel appearance, and a lid material using the same can be provided.

Modes for Carrying Out the Invention

[0018] Hereinafter, each component constituting the hot-melt adhesive of the present invention will be described in detail. It goes without saying that other embodiments are also included in the scope of the present invention as long as they conform to the gist of the present invention. In this specification, a numerical range specified using "~" shall include the numerical values described before and after "~" as the range of the lower limit value and the upper limit value.

[0019] ≪Hot-Melt Adhesive≫ The hot melt adhesive of the present invention contains, in 100% by mass of the hot melt adhesive, 20 to 50% by mass of an ethylene-vinyl acetate copolymer (A) having a melt mass flow rate of 3 to 400 g / 10 min at 190°C and a load of 2.16 kg, 10 to 30% by mass of a tackifying resin (B) having a softening point of 90 to 150°C, 20 to 50% by mass of a wax (C) having a melting point of 60 to 120°C, 5 to 25% by mass of talc (D), and 0.1 to 2.0% by mass of silicone oil (E). By using such a hot melt adhesive, it has heat resistance such that seal peeling does not occur even in a high-temperature environment, there is no dipping during peeling, and a hot melt adhesive showing stable seal strength and excellent peel appearance can be obtained. The hot melt adhesive of the present invention can be suitably used for a lid material.

[0020] <Ethylene-vinyl acetate copolymer (A)> The ethylene-vinyl acetate copolymer (A) is a copolymer of ethylene and vinyl acetate. It is one of the main components in the hot melt adhesive and mainly plays a role in imparting adhesive strength and cohesive strength. The ethylene-vinyl acetate copolymer (A) may be used alone or in combination of two or more.

[0021] The content of the ethylene-vinyl acetate copolymer (A) in 100% by mass of the hot melt adhesive of the present invention is in the range of 20 to 50% by mass. If the content is less than 20% by mass, the adhesiveness becomes insufficient, and it is inferior in heat resistance and easy peelability. If it exceeds 50% by mass, the viscosity increases and the coating suitability decreases. The content of the ethylene-vinyl acetate copolymer (A) is preferably in the range of 25 to 45% by mass.

[0022] In addition, the melt mass flow rate of the ethylene-vinyl acetate copolymer (A) at 190°C and a load of 2.16 kg is in the range of 3 to 400 g / 10 min. The melt mass flow rate is the amount (g / 10 min) that flows out in 10 minutes at 190°C and a load of 2.16 kg, measured in accordance with JIS K 7210. If the melt mass flow rate is less than 3 g / 10 min, the viscosity of the hot melt adhesive increases and the coating suitability decreases. If it exceeds 400 g / 10 min, the heat resistance is insufficient. The melt mass flow rate of the ethylene-vinyl acetate copolymer (A) at 190°C and a load of 2.16 kg is preferably in the range of 10 to 150 g / 10 min.

[0023] The vinyl acetate content of the ethylene-vinyl acetate copolymer (A) is preferably in the range of 20 to 35% by mass, more preferably in the range of 25 to 32% by mass. By setting the vinyl acetate content within the above range, excellent adhesive strength and low-temperature heat sealability can be obtained. The vinyl acetate content means the content (% by mass) of vinyl acetate monomer in 100% by mass of the ethylene-vinyl acetate copolymer (A).

[0024] When using a plurality of ethylene-vinyl acetate copolymers, the vinyl acetate content can be calculated from the vinyl acetate content and the blending ratio of each ethylene-vinyl acetate copolymer. For example, when the vinyl acetate content of the first ethylene-vinyl acetate copolymer is VA1 and the blending amount is W1, and the vinyl acetate content of the second ethylene-vinyl acetate copolymer is VA2 and the blending amount is W2, the overall vinyl acetate content VA can be obtained by the following formula. (Formula) VA = (VA1 × W1 + VA2 × W2) / (W1 + W2)

[0025] <Adhesion-imparting resin (B)> The adhesion-imparting resin (B) used in the present invention can be appropriately selected from known ones. For example, phenolic resins, xylene resins, coumarone-indene resins, petroleum resins, rosin resins, terpene resins, etc. can be mentioned. Examples of phenolic resins include phenol resins, modified phenol resins, xylenol resins, alkylphenol resins, and the like. Examples of petroleum resins include aliphatic (C5-based) petroleum resins, aromatic (C9-based) petroleum resins, copolymer (C5 / C9-based) petroleum resins, alicyclic petroleum resins (hydrogenated or dicyclopentadiene (DCPD)-based petroleum resins), and low molecular weight polystyrene-based resins. Examples of rosin-based resins include rosin, rosin derivatives (hydrogenated rosin, disproportionated rosin, polymerized rosin, rosin esters (esterified rosin with alcohols, glycerin, pentaerythritol, etc.)), and the like. Examples of terpene-based resins include α-pinene resins, β-pinene resins, dipentene resins, aromatic-modified terpene resins, hydrogenated terpene resins, terpene phenol resins, acid-modified terpene resins, styrenated terpene resins, and terpene-based resins. Among them, from the viewpoints of easy peelability and dipping suppression, petroleum resins and terpene-based resins are preferably used, and the tackifying resin (B) preferably contains a petroleum resin and / or a terpene-based resin. The petroleum resin and terpene-based resin may be used in combination with other tackifying resins.

[0026] The content of the tackifying resin (B) in 100% by mass of the hot melt adhesive is 10 to 30% by mass, preferably 15 to 25% by mass. When the content of the tackifying resin is less than 10% by mass, the heat resistance and easy peelability decrease, and when it exceeds 30% by mass, the blocking resistance and easy peelability decrease.

[0027] The softening point of the tackifying resin (B) is in the range of 90 to 150°C, preferably in the range of 100 to 145°C, and more preferably in the range of 120 to 140°C. When the softening point is within the above range, the heat resistance and low-temperature heat sealability are good. The softening point of the tackifier resin (B) can be determined in accordance with JIS K 2207. Specifically, after allowing a specified ring filled with the resin composition to stand for 12 hours or more, it is placed in a heat medium, a specified ball is placed on the specified ring filled with the resin composition, and when the temperature of the heat medium is increased at a constant rate, it is the temperature at which the ball sinks and touches the bottom plate of the ring stand due to the softening of the resin composition. When the tackifier resin (B) contains a plurality of tackifier resins, the softening point of the tackifier resin (B) can be determined from the softening points of the respective tackifier resins and their mass ratios.

[0028] <Wax (C)> The wax (C) used in the present invention can be appropriately selected from known ones. For example, paraffin wax, microcrystalline wax, montan wax, Fischer-Tropsch wax, carnauba wax, ethylene wax, polyethylene wax, propylene wax, polypropylene wax, ethylene-propylene wax, polyethylene-polypropylene wax, modified waxes such as those obtained by grafting styrene onto a polyethylene-polypropylene copolymer, etc. Among them, from the viewpoints of heat resistance and blocking resistance, paraffin wax and Fischer-Tropsch wax are preferably used. These waxes may be used alone or in combination of two or more.

[0029] The content of the wax (C) in 100% by mass of the hot melt adhesive is 20 to 50% by mass, preferably 25 to 45% by mass. If it is less than 20% by mass, the coating suitability deteriorates due to an increase in viscosity and the blocking resistance decreases. If it exceeds 50% by mass, the opening strength decreases.

[0030] The melting point of wax (C) is in the range of 60 to 120°C, preferably in the range of 60 to 100°C. By setting the melting point within the above range, the heat resistance and low-temperature heat sealability of the hot melt adhesive are improved. In this specification, the melting point is the peak top temperature when the temperature is raised at a rate of 10°C / min in accordance with JIS K7121:1987 by differential scanning calorimetry (DSC) measurement. The details of the melting point measurement method are described in the examples.

[0031] Further, from the viewpoints of low-temperature sealability, heat resistance, and blocking resistance, the hot melt adhesive of the present invention preferably contains 50% by mass or more, more preferably 70% by mass or more, of wax (C1) having a melting point of 60 to 100°C and satisfying the following formula in 100% by mass of wax (C). The content of wax (C1) in 100% by mass of wax (C) is preferably higher, and particularly preferably 100% by mass. (Formula) 5°C ≤ Y - X ≤ 30°C X: Onset temperature of the endothermic peak in the DSC curve obtained by differential scanning calorimetry (DSC) measurement Y: Endset temperature of the endothermic peak in the DSC curve obtained by differential scanning calorimetry (DSC) measurement

[0032] The melting point of wax (C1) is more preferably in the range of 70 to 90°C. When the melting point is in the range of 70 to 90°C, the heat resistance and low-temperature heat sealability of the hot melt adhesive are improved.

[0033] The difference (Y - X) between the endset temperature and the onset temperature of wax (C1) is 5°C ≤ Y - X ≤ 30°C, preferably in the range of 5°C ≤ Y - X ≤ 20°C. By setting the range as above, an excellent hot melt adhesive capable of achieving both heat resistance and low-temperature heat sealability can be obtained. In this specification, the extrapolated onset melting temperature (Tim) defined in JIS K7121:1987 is used as the onset temperature (X), and the extrapolated end melting temperature (Tem) is used as the endset temperature (Y). When there are multiple endothermic peaks, the calculation is performed using the onset temperature of the lowermost endothermic peak and the endset temperature of the uppermost endothermic peak.

[0034] Examples of commercially available waxes (C1) include "KH Paraffin Wax 70H" (melting point: 70°C, Y-X: 25°C) manufactured by King Honor International, "Sasol C80" (melting point 83°C, Y-X: 18°C) manufactured by Sasol, "HNP-3" (melting point: 66°C, Y-X: 18°C) manufactured by Nippon Seiro Co., Ltd., and the like.

[0035] <Talc (D)> The hot melt adhesive of the present invention contains talc (D). By adding talc (D) to the hot melt adhesive, cohesive failure in the hot melt layer can be promoted and dipping during peeling can be suppressed. Note that cohesive failure is a peeling form in which the adhesive layer breaks. From the viewpoint of sedimentation properties, talc preferably has a relatively small average particle size. The average particle size of talc is preferably 50 μm or less, more preferably 30 μm or less, and still more preferably 20 μm or less. Here, the average particle size of talc is the average particle size (D50 (median diameter of particle size distribution)) measured by the sedimentation method. Talc (D) may be used alone or in combination of two or more.

[0036] The content of talc (D) in 100% by mass of the hot melt adhesive is 5 to 25% by mass, preferably 10 to 20% by mass. If it is less than 5% by mass, the ratio of cohesive failure in the hot melt layer decreases and dipping during peeling becomes likely. If it exceeds 25% by mass, the heat resistance and unsealing strength decrease.

[0037] <Silicone Oil (E)> Silicone oil (E) is mainly compounded for the purpose of improving the blocking resistance and slipperiness of the coated product of the hot melt adhesive. Further, by using the talc (D) and the silicone oil (E) in combination, a synergistic effect is produced, and even when the addition amount of the talc is small, the cohesive failure of the hot melt layer can be promoted, and the dipping at the time of peeling can be suppressed. Examples of the silicone oil (E) include dimethyl silicone oil, methylphenyl silicone oil, and methylhydrogen silicone oil. These silicone oils may be used alone or in combination of two or more.

[0038] The content of the silicone oil (E) in 100% by mass of the hot melt adhesive is 0.1 to 2.0% by mass, preferably 0.5 to 1.5% by mass. If it is less than 0.1% by mass, the blocking resistance decreases and the ratio of cohesive failure of the hot melt layer decreases. If it exceeds 2.0% by mass, the heat resistance and the unsealing strength decrease due to bleed-out.

[0039] The kinematic viscosity of the silicone oil (E) in the hot melt adhesive of the present invention at 25°C is preferably 50 to 10,000 mm 2 / s, more preferably 100 to 1,000 mm 2 / s. By setting the kinematic viscosity within the above range, the cohesive failure in the hot melt layer is promoted, and the blocking resistance and the heat resistance become good. The kinematic viscosity of the silicone oil (E) is measured in accordance with JIS Z8803:2011.

[0040] <Other components> The hot melt adhesive of the present invention can contain an antioxidant, a silane coupling agent, an anti-blocking agent, hydrophobic oxide fine particles, etc. as optional components. These other components may be used alone or in combination of two or more.

[0041] Examples of the antioxidant include phenolic antioxidants and phosphorus antioxidants. Specific examples include pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, diethyl [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-t-butyl-4-hydroxy-m-tolyl]propionate, tris(2,4-di-t-butylphenyl) phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, and the like. Among the phenolic antioxidants, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] is preferred, and among the phosphorus antioxidants, tris(2,4-di-t-butylphenyl) phosphite is preferred.

[0042] Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, mercaptobutyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, and the like.

[0043] Examples of the anti-blocking agent include unsaturated fatty acid amides such as erucic acid amide and oleic acid amide; saturated fatty acid amides such as stearic acid amide and behenic acid amide.

[0044] Examples of the hydrophobic oxide fine particles include silica (silicon dioxide), alumina, titania, calcium oxide, calcium carbonate, calcium sulfate, calcium silicate, and the like.

[0045] From the viewpoint of suppressing bleed-out, the content of the above optional component is preferably 10% by mass or less, more preferably 8% by mass or less, based on the mass of the hot melt adhesive.

[0046] <Method for producing hot melt adhesive> The hot melt adhesive of the present invention can be obtained by mixing an ethylene-vinyl acetate copolymer (A), a tackifying resin (B), a wax (C), talc (D), a silicone oil (E), and an optional component used as necessary by a known method. For example, a heat-melt type hot melt adhesive can be obtained by heating and mixing using a roll, a Banbury mixer, a kneader, a melting kettle equipped with a stirrer, or a single-screw or twin-screw extruder. Further, for example, a solvent-type hot melt adhesive can be obtained by dissolving in a known solvent and stirring and mixing. The hot melt adhesive of the present invention is preferably used for lid materials, and from the viewpoint of residual solvents, it is preferably a heat-melt type hot melt adhesive that does not use a solvent.

[0047] From the viewpoint of coating applicability, the hot melt adhesive of the present invention preferably has a melt viscosity at 160 ° C in the range of 500 to 5,000 mPa·s. The melt viscosity in this specification is a value measured under the conditions of 160 ° C, rotor No. 3, 12 rpm, and 30 seconds using a B-type viscometer in accordance with JIS K 6862.

[0048] ≪Lid material≫ The hot melt adhesive of the present invention can be suitably used for lid materials. The lid material of the present invention is provided with a hot melt layer made of the hot melt adhesive of the present invention on one side of a base material, and can be used for an openable container. The manufacturing method of the lid material is not particularly limited, and it can be manufactured using a known manufacturing method. The method for forming the hot melt layer is not particularly limited, and either a contact coating method or a non-contact coating method may be used. The contact coating method is a coating method in which an ejector is brought into contact with a member or a film when applying the hot melt adhesive. Examples thereof include slot coater coating, gravure coater coating, and roll coater coating. The non-contact coating method is a coating method in which an ejector is not brought into contact with a member or a film when applying the hot melt adhesive. Examples thereof include spiral coating that can be applied in a spiral shape, omega coating that can be applied in a wave shape, control seam coating, slot spray coating that can be applied in a planar shape, curtain spray coating, dot coating that can be applied in a dot shape, and bead coating that can be applied in a linear shape. The thickness of the hot melt layer is usually in the range of 1 to 100 μm. Further, the hot melt layer may be crosslinked by heating or ultraviolet irradiation.

[0049] [Base material] The base material that can be used for the lid material of the present invention is a base material in which at least two or more selected from the group consisting of resin, paper, and aluminum are laminated. The resin constituting the base material preferably includes at least one selected from the group consisting of polyester resins such as polyethylene terephthalate resin, polyolefin resins such as polyethylene, polypropylene, and polynorbornene, polycarbonate resin, polyarylate resin, acrylic resin, polyphenylene sulfide resin, polystyrene resin, vinyl resin, vinyl chloride resin, polyimide resin, and epoxy resin, and more preferably includes at least one resin selected from the group consisting of polyethylene resin, polypropylene resin, and polyethylene terephthalate resin. The resin layer may have a metal vapor deposition layer obtained by vapor depositing a metal such as aluminum, or a transparent vapor deposition layer obtained by vapor depositing alumina, silicon oxide, or the like. As the metal in the metal layer, aluminum is preferably used, and examples thereof include aluminum foil and an aluminum vapor deposition layer. The base material may further have other layers such as non-woven fabric, woven fabric, cloth, and glass.

[0050] Preferably, examples of the configuration of the base material include "paper / polyethylene resin", "polyethylene terephthalate resin / paper / polyethylene resin", and "polyethylene terephthalate resin / aluminum foil / polyethylene resin". Further, the surface of the base material may be subjected to adhesion-promoting treatment, antistatic treatment, coloring treatment, or the like, such as corona discharge treatment, plasma treatment, blasting treatment, and chemical etching treatment, as necessary. The thickness of the base material is not particularly limited and is usually in the range of 1 to 300 μm.

[0051] ≪Sealing container member set, sealed container≫ The sealing container member set of the present invention consists of a container and the above-mentioned lid material. Further, the sealing container member set can be used as an unsealable sealed container by heat-sealing the opening of the container and the lid material with a hot melt layer. Generally, it can be said that the unsealing property is good if the unsealing strength is in the range of 5 to 15 N. The unsealable sealed container of the present invention preferably has an unsealing strength in the range of 5 to 20 N when the coating amount of the hot melt layer is in the range of 10 to 30 g / m 2 of.

[0052] <Container> Examples of the container used in the present invention include containers made of polystyrene, polyethylene, polypropylene, polyethylene terephthalate, etc., and a container made of polystyrene is particularly preferred. Moreover, any form may be used as long as it is a container that can hold the contents, and a form of a molded container generally used for filling and storing food and beverages is preferred.

Examples

[0053] Hereinafter, the present invention will be described specifically and in detail with reference to examples. However, these examples are merely one aspect of the present invention, and the present invention is not limited by these examples. In the examples, "parts" represents "parts by mass", and "%" represents "% by mass".

[0054] [Melting point] DSC measurement was performed using a differential scanning calorimeter (DSC-60A plus) manufactured by Shimadzu Corporation calibrated with an indium standard to determine the melting point (Tm). The above measurement sample was weighed on an aluminum DSC pan so as to be 10 mg of the sample, and the lid was crimped onto the pan to create an airtight atmosphere, obtaining a sample pan. Next, the sample pan was placed in a DSC cell, and an empty aluminum pan was placed as a reference. Using DSC, the temperature was raised from room temperature to 200 °C at a rate of 10 °C / min under a nitrogen flow of 30 mL / min, then cooled to -80 °C at a rate of 10 °C / min, and the temperature was raised again to 170 °C at a rate of 10 °C / min to measure the DSC curve. The melting point, onset temperature (X), and endset temperature (Y) were determined from the endothermic curve observed in the second heating process.

[0055] <Manufacture of hot melt adhesive> (Example 1) In a stainless steel beaker equipped with a stirrer, 37 parts of C1-1 (Sazol C80) as wax (C) and 0.1 part of Irganox 1010 as an antioxidant were added, and heating was carried out while taking care that the contents did not exceed 180°C. After confirming the melting of the wax, stirring was started, and 37 parts of A1 (Ultra-Sen 752) as ethylene-vinyl acetate copolymer (A), 20 parts of B1 (Alcon P-125) as tackifier resin (B), 5 parts of D1 (MS-K) as talc (D), and 0.9 part of E3 (Silicone oil KF-96-20cs) as silicone oil (E) were added, and stirring was carried out until completely mixed to obtain a hot melt adhesive.

[0056] (Examples 2 to 39, Comparative Examples 1 to 14) A hot melt adhesive was obtained in the same manner as in Example 1, except that the material amounts and compounding ratios (by mass) shown in Tables 1 to 3 were changed.

[0057] The abbreviations described in Tables 1 to 3 are as shown below. <Ethylene-vinyl acetate copolymer (A)> · A1: Ultra-Sen 752 (Ethylene-vinyl acetate copolymer manufactured by Tosoh Corporation, vinyl acetate content: 32%, MFR: 60 g / 10 min) · A2: Ultra-Sen 720 (Ethylene-vinyl acetate copolymer manufactured by Tosoh Corporation, vinyl acetate content: 28%, MFR: 150 g / 10 min) · A3: Ultra-Sen 722 (Ethylene-vinyl acetate copolymer manufactured by Tosoh Corporation, vinyl acetate content: 28%, MFR: 400 g / 10 min) · A4: Ultra-Sen 633 (Ethylene-vinyl acetate copolymer manufactured by Tosoh Corporation, vinyl acetate content: 20%, MFR: 20 g / 10 min) · A5: Ultra-Sen 625 (Ethylene-vinyl acetate copolymer manufactured by Tosoh Corporation, vinyl acetate content: 15%, MFR: 14 g / 10 min) <Other ethylene-vinyl acetate copolymers (A’)> · A’1: Ultra-Sen 735 (Ethylene-vinyl acetate copolymer manufactured by Tosoh Corporation, vinyl acetate content: 28%, MFR: 1000 g / 10 min)

[0058] <Adhesion-imparting resin (B)> · B1: Alcon P-125 (manufactured by Arakawa Chemical Industries, hydrogenated petroleum resin, softening point: 125 °C) · B2: Alcon P-140 (manufactured by Arakawa Chemical Industries, hydrogenated petroleum resin, softening point: 140 °C) · B3: Alcon P-100 (manufactured by Arakawa Chemical Industries, hydrogenated petroleum resin, softening point: 100 °C) · B4: Clearon P-125 (manufactured by Yasuhara Chemical, hydrogenated terpene resin, softening point: 125 °C) · B5: Haritack FK125 (manufactured by Harima Chemicals, rosin ester, softening point: 125 °C) <Other adhesion-imparting resin (B’)> · B’1: Haritack F85 (manufactured by Harima Chemicals, rosin ester, softening point: 85 °C)

[0059] <Wax (C1)> · C1-1: Sasol C80 (manufactured by Sasol Chemical Industries, Fischer-Tropsch wax, DSC melting point: 83 °C, Y-X: 18 °C) · C1-2: KH Paraffin Wax 70H (manufactured by King Honor Internationals, paraffin wax, DSC melting point: 70 °C, Y-X: 25 °C) · C1-3: HNP-3 (manufactured by Nippon Seiro Co., Ltd., paraffin wax, DSC melting point: 66 °C, Y-X: 18 °C) <Wax other than (C1) (C): (C2)> · C2-1: Hiwax NL800 (manufactured by Mitsui Chemicals, polyethylene wax, DSC melting point: 104 °C, Y-X: 12 °C) · C2-2: KH Paraffin Wax 80M (manufactured by King Honor Internationals, paraffin wax, DSC melting point: 79 °C, Y-X: 79 °C) · C2-3: KH Paraffin Wax F60 (manufactured by King Honor Internationals, paraffin wax, DSC melting point: 62 °C, Y-X: 35 °C) <Other wax (C’)> ·C’1: Paraffin Wax-125 (manufactured by Nippon Seiro Co., Ltd., paraffin wax, DSC melting point: 54°C, Y-X: 32°C) ·C’2: Hiwax 200P (manufactured by Mitsui Chemicals, Inc., polyethylene wax, DSC melting point: 124°C, Y-X: 8°C)

[0060] <Talc (D)> ·D-1: MS-K (manufactured by Nippon Talc Co., Ltd., average particle size: 16 μm) ·D-2: PAOG-R (manufactured by Nippon Talc Co., Ltd., average particle size: 30 μm)

[0061] <Silicone Oil (E)> ·E-1: Silicone Oil KF-96-20cs (manufactured by Shin-Etsu Silicone Co., Ltd., kinematic viscosity: 20 mm 2 / s) ·E-2: Silicone Oil KF-96-50cs (manufactured by Shin-Etsu Silicone Co., Ltd., kinematic viscosity: 50 mm 2 / s) ·E-3: Silicone Oil KF-96-100cs (manufactured by Shin-Etsu Silicone Co., Ltd., kinematic viscosity: 100 mm 2 / s) ·E-4: Silicone Oil KF-96-1000cs (manufactured by Shin-Etsu Silicone Co., Ltd., kinematic viscosity: 1,000 mm 2 / s) ·E-5: Silicone Oil KF-96-10000cs (manufactured by Shin-Etsu Silicone Co., Ltd., kinematic viscosity: 10,000 mm 2 / s) ·E-6: Silicone Oil KF-96-50000cs (manufactured by Shin-Etsu Silicone Co., Ltd., kinematic viscosity: 50,000 mm 2 / s)

[0062] <Additive> ·Antioxidant: Irganox1010 (manufactured by BASF Japan Ltd.)

[0063] <Evaluation Method for Hot Melt Adhesive> The following evaluations were conducted on the coating suitability of the obtained hot melt adhesive, and the heat resistance, dipping, peel appearance, low-temperature heat sealability, blocking resistance, and easy-openability of the lid material manufactured using the hot melt adhesive. The results are shown in Tables 1 and 2.

[0064] [Coating suitability (melt viscosity)] For the obtained hot melt adhesive, the melt viscosity was measured in accordance with JIS K 6862. Specifically, using a B-type viscometer, measurements were taken under the conditions of a temperature of 160 °C, rotor No. 3, rotation speed of 12 rpm, and for 30 seconds, and evaluations were made according to the following criteria. ○: Melt viscosity is 5,000 mPa·s or less (usable) ×: Melt viscosity exceeds 5,000 mPa·s (not usable)

[0065] [Fabrication of lid material] On the PE surface of a base material in which 20 μm of polyethylene terephthalate (PET), 15 μm of aluminum foil (Al), and 20 μm of polyethylene (PE) were laminated in this order, using a gravure coater, the hot melt adhesive was applied at a coating amount of 16 g / m 2 to obtain a lid material.

[0066] [Heat resistance] The obtained lid material was cut into a size of 70 mm × 15 mm. The end of the obtained lid material with a size of 70 mm × 15 mm was overlapped near the center of a polystyrene (PS) sheet with a size of 70 mm × 15 mm, and heat-sealed under the conditions of a gauge pressure of 0.1 MPa, a seal temperature of 150 °C, a seal time of 1.0 second, and an adhesive area of 20 mm × 15 mm to prepare a test piece. Using a tensile strength tester, the obtained test piece was placed in a thermostat at 50 °C, and the peel strength was measured by 180-degree peeling at a speed of 200 mm / min. The measurement was performed 5 times, and the average value of the average strength (N / 15 mm) was taken as the heat resistance strength, and the heat resistance was evaluated according to the following criteria. 〇: Heat resistance strength is 6 N / 15 mm or more (good) △: Heat resistance strength is 4 N / 15 mm or more and less than 6 N / 15 mm (usable) ×: Heat resistance strength is less than 4 N / 15 mm (not usable)

[0067] [Dipping] The obtained lid material was cut into a size of 70 mm × 70 mm, heat-sealed and sealed with a PS container having an opening size of 52 mmΦ under the conditions of a gauge pressure of 0.3 MPa, 150°C, and 1.0 second to obtain a container. The obtained container was allowed to stand in a thermo-hygrostat chamber at a temperature of 23°C and a relative humidity of 65% for 24 hours, and then the presence or absence of dipping when peeled at a 45-degree angle at a speed of 200 mm / min in the same chamber was evaluated according to the following criteria. 〇: No dipping is observed (usable) △: Slight dipping is observed (usable) ×: Dipping is observed overall (not usable)

[0068] [Peeling appearance] The obtained lid material was cut into a size of 70 mm × 70 mm, heat-sealed and sealed with a PS container having an opening size of 52 mmΦ under the conditions of a gauge pressure of 0.3 MPa, 150°C, and 1.0 second to obtain a container. The obtained container was allowed to stand in a thermo-hygrostat chamber at a temperature of 23°C and a relative humidity of 65% for 24 hours, and then the ratio of the area of cohesive failure to the heat-sealing area when peeled at a 45-degree angle at a speed of 200 mm / min in the same chamber was observed, and the peeling appearance was evaluated according to the following criteria. 〇: The ratio of the area of cohesive failure is 90% or more (good) △: The ratio of the area of cohesive failure is 50% or more and less than 90% (usable) ×: The ratio of the area of cohesive failure is less than 50% (not usable)

[0069] [Low-temperature heat-sealing property] The obtained lid material was cut into a size of 70 mm × 70 mm, heat-sealed and sealed with a PS container having an opening size of 52 mmΦ under the conditions of a gauge pressure of 0.3 MPa, 120°C, and 1.0 second to obtain a container. The obtained container was allowed to stand in a thermo-hygrostat chamber at a temperature of 23°C and a relative humidity of 65% for 24 hours, and then the peel strength was measured by peeling at a 45-degree angle at a speed of 200 mm / min in the same chamber. The measurement was performed 5 times, and the average value of the maximum load (N) at the time of opening was taken as the opening strength, and the easy-openability was evaluated according to the following criteria. 〇: Opening strength is 10 N or more and less than 15 N (good) △: Opening strength is 5 N or more and less than 10 N, or 15 N or more and less than 20 N (usable) ×: Opening strength is less than 5 N, or 20 N or more (unusable)

[0070] [Blocking resistance] The lid material was cut into 5 pieces with a size of 5 cm × 5 cm, and stacked so that the PET surface of the laminate was in contact with the hot melt surface. The stacked samples were aged at 40 °C for 24 hours under a load of 10 kg. After taking out the samples and leaving them in an atmosphere of 23 °C and 65% relative humidity for 2 hours, the stacked samples were peeled off by hand. The state at the time of peeling was evaluated according to the following criteria. 〇: Peels off without resistance. (Very good) △: There is some resistance. (Usable) ×: The resistance at the time of peeling is large, or peeling is impossible. (Unusable)

[0071] [Ease of opening] The obtained lid material was cut into a size of 70 mm × 70 mm, heat-sealed and sealed with a 52 mm Φ PS container with an opening size under the conditions of a gauge pressure of 0.3 MPa, 150 °C, and 1.0 second to obtain a container. The obtained container was left standing in a constant temperature and humidity chamber at a temperature of 23 °C and a relative humidity of 65% for 24 hours, and then the peel strength was measured by peeling at a 45-degree angle at a speed of 200 mm / min in the same chamber. The measurement was performed 5 times, and the average value of the maximum load (N) at the time of opening was taken as the opening strength, and the ease of opening was evaluated according to the following criteria. 〇: Opening strength is 10 N or more and less than 15 N (good) △: Opening strength is 5 N or more and less than 10 N, or 15 N or more and less than 20 N (usable) ×: Opening strength is less than 5 N, or 20 N or more (unusable)

[0072]

Table 1

[0073]

Table 2

[0074]

Table 3

[0075] According to the evaluation results, in addition to a specific ethylene-vinyl acetate copolymer, wax, and tackifier resin, the hot melt adhesive of the present application obtained by using a specific amount of talc and silicone oil in combination has good coating applicability, blocking resistance, and low-temperature heat sealability, and in addition, has excellent heat resistance, easy peelability, and peel appearance, and has been shown to be useful as a hot melt adhesive for lid materials. On the other hand, in the comparative examples using talc and silicone oil alone, the ratio of cohesive failure in the hot melt layer decreased and the peel appearance deteriorated.

Claims

1. In 100% by mass of the hot melt adhesive, 20 to 50% by mass of an ethylene-vinyl acetate copolymer (A) having a melt mass flow rate of 3 to 400 g / 10 min at 190°C and a load of 2.16 kg, a tackifier resin (B) having a softening point of 90 to 150°C is 10 to 30% by mass, a wax (C) having a melting point of 60 to 120°C is 20 to 50% by mass, talc (D) is 5 to 25% by mass, and silicone oil (E) is 0.1 to 2.0% by mass. A hot melt adhesive characterized by containing.

2. The hot melt adhesive according to claim 1, wherein the wax (C) contains 50% by mass or more of a wax (C1) having a melting point of 60 to 100°C and satisfying the following formula in 100% by mass of the wax (C). (Formula) 5°C ≤ Y - X ≤ 30°C X: Onset temperature of the endothermic peak in the DSC curve obtained by differential scanning calorimetry (DSC) measurement Y: Endset temperature of the endothermic peak in the DSC curve obtained by differential scanning calorimetry (DSC) measurement

3. The hot melt adhesive according to claim 1, wherein the tackifier resin (B) contains a petroleum resin and / or a terpene resin.

4. The kinematic viscosity at 25°C of the silicone oil (E) is 50 to 10,000 mm ２ / s, and the hot melt adhesive according to claim 1 is characterized by this.

5. The hot melt adhesive according to any one of claims 1 to 4, wherein the vinyl acetate content of the ethylene-vinyl acetate copolymer (A) is 20 to 35% by mass.

6. A lid material provided with a hot melt layer made of the hot melt adhesive according to claim 5 on one side of a substrate in which at least two or more selected from the group consisting of a resin sheet, paper, and an aluminum sheet are laminated.

7. An openable sealed container member set comprising a container and the lid material according to claim 6.

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