WO2023027067A1 - 積層体、感熱ラベル、インモールドラベル及びラベル付き容器 - Google Patents

積層体、感熱ラベル、インモールドラベル及びラベル付き容器 Download PDF

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Publication number
WO2023027067A1
WO2023027067A1 PCT/JP2022/031710 JP2022031710W WO2023027067A1 WO 2023027067 A1 WO2023027067 A1 WO 2023027067A1 JP 2022031710 W JP2022031710 W JP 2022031710W WO 2023027067 A1 WO2023027067 A1 WO 2023027067A1
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Prior art keywords
resin
layer
heat seal
heat
label
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Ceased
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PCT/JP2022/031710
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English (en)
French (fr)
Japanese (ja)
Inventor
雅彦 上野
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Yupo Corp
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Yupo Corp
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Priority to JP2023543928A priority Critical patent/JP7769709B2/ja
Priority to US18/685,329 priority patent/US12499783B2/en
Publication of WO2023027067A1 publication Critical patent/WO2023027067A1/ja
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F3/00—Labels, tag tickets, or similar identification or indication means; Seals; Postage or like stamps
    • G09F3/08—Fastening or securing by means not forming part of the material of the label itself
    • G09F3/10—Fastening or securing by means not forming part of the material of the label itself by an adhesive layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F3/00—Labels, tag tickets, or similar identification or indication means; Seals; Postage or like stamps
    • G09F3/02—Forms or constructions
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F3/00—Labels, tag tickets, or similar identification or indication means; Seals; Postage or like stamps
    • G09F3/02—Forms or constructions
    • G09F2003/023—Adhesive
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F3/00—Labels, tag tickets, or similar identification or indication means; Seals; Postage or like stamps
    • G09F3/02—Forms or constructions
    • G09F2003/0272—Labels for containers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/80—Packaging reuse or recycling, e.g. of multilayer packaging

Definitions

  • the present invention relates to laminates, thermal labels, in-mold labels, and labeled containers.
  • resin containers are used as containers for drinking water, cosmetics, seasonings, etc. With the mass consumption of products, discarded resin containers are recycled as new resources in order to reduce the burden on the environment.
  • labels are often affixed to resin containers, the labels are removed from the resin containers during recycling.
  • alkaline water (1.5% NaOH aqueous solution) at a high temperature of about 85 to 90°C to remove the labels. It is A label that is easily peeled off by this high-temperature alkaline water has been developed (see, for example, Patent Document 1).
  • An object of the present invention is to provide a laminate that has sufficient adhesive strength with an adherend such as a resin container and that is easily peeled off by high-temperature water treatment.
  • the present invention is as follows.
  • the heat seal layer (A) is the outermost layer of the laminate,
  • the heat seal layer (A) contains a heat seal resin (a) and a water-soluble resin (c),
  • a laminate, wherein the mass ratio of the heat seal resin (a) and the water-soluble resin (c) in the heat seal layer (A) is 70:30 to 45:55.
  • the heat seal layer (B) contains a heat seal resin (b), The laminate according to [4] above, wherein the heat seal resin (b) is an olefin resin having a melting point of 50 to 115°C.
  • thermosensitive label comprising the laminate according to any one of [1] to [6] above.
  • the laminate, thermal label, in-mold label and labeled container of the present invention are described below.
  • the following description is an example (representative example) of the present invention, and the present invention is not limited thereto.
  • the description of "(meth)acrylic” indicates both acrylic and methacrylic.
  • the laminate of the present invention has a substrate layer and a heat seal layer (A).
  • the heat seal layer (A) is the outermost layer of the laminate and contains the heat seal resin (a) and the water-soluble resin (c) at a specific mass ratio of 70:30 to 45:55. .
  • the laminate of the present invention can be adhered to an adherend via the heat seal layer (A), and can be preferably used as, for example, a thermal label, especially an in-mold label.
  • a thermal label especially an in-mold label.
  • the laminate is placed in a mold for molding a resin container and adhered to the outer surface of the resin container via the heat seal layer (A) melted by the heat during molding.
  • in-mold labels are attached so that they are integrated with the resin container, so it is difficult to remove the label.
  • high temperature water treatment a treatment of immersion in high temperature water of 75 to 80 ° C. for a certain period of time
  • the water-soluble resin (c) in the heat seal layer (A) dissolves in hot water. Since the heat seal layer (A) is destroyed by dissolution, the label is easily peeled off from the resin container. Therefore, the label can be easily peeled off from the labeled container by high-temperature water treatment, and the recyclability of the resin container is enhanced. Since high-temperature alkaline water is not used, neutralization is not required and process control is easy.
  • the label may peel off even during normal use such as during storage, transportation, or use.
  • the adhesive strength to stretch blow molded articles such as polyethylene terephthalate (PET) tends to be weaker than the adhesive strength to direct blow molded articles such as polypropylene.
  • the present invention by controlling the blending amount of the water-soluble resin (c) to a specific mass ratio with respect to the heat seal resin (a), not only the direct blow molded olefin resin but also the stretch Sufficient adhesive strength with resin containers such as ester-based resins to be blow-molded could be obtained. Therefore, even if the water-soluble resin (c) is blended in the heat seal layer (A), it is possible to provide a laminate that is difficult to separate under normal conditions of use and easy to separate during high-temperature water treatment.
  • the laminate of the present invention preferably has another heat-sealing layer (B) between the substrate layer and the heat-sealing layer (A).
  • the heat-sealing layer (B) can reinforce the heat-sealing property of the laminate, facilitating adjustment to increase the adhesive strength with an adherend such as a resin container.
  • the laminate of the present invention can be preferably used as a label for resin containers that are often recycled, it can be heat-sealed to adherends made of resin other than resin containers. Even in this case, the label can be peeled off from the adherend by hot water treatment.
  • FIG. 1 shows an example of the laminate of the present invention.
  • a laminate 10 illustrated in FIG. 1 has a base layer 1 and two heat seal layers 21 and 22 .
  • the heat seal layer 21 is an example of the heat seal layer (A)
  • the heat seal layer 22 is an example of the heat seal layer (B).
  • a printed layer 5 may be provided by printing on the surface of the substrate layer 1 opposite to the heat seal layer 21 .
  • each layer will be described with an example of using the laminate of the present invention as a label for a resin container, but as will be described later, the laminate of the present invention can be used for various purposes other than labels. .
  • Heat seal layer (A) The heat seal layer (A) is arranged on the outermost surface of the laminate of the present invention and imparts heat sealability to the laminate. As described above, the heat seal layer (A) contains the heat seal resin (a) and the water-soluble resin (c).
  • Heat seal resin (a) When the laminate of the present invention is adhered to a resin container, the heat-sealing resin (a) is melted by heat during, for example, in-mold molding to increase the adhesive strength of the laminate.
  • the heat seal resin (a) can be selected from one or more thermoplastic resins having a low melting point.
  • the melting point of the heat seal resin (a) is preferably 50°C or higher, more preferably 60°C or higher, even more preferably 70°C or higher, and particularly preferably 80°C or higher. This makes it difficult for blocking between the laminates to occur.
  • the melting point of the heat seal resin (a) is preferably lower than the melting point of the thermoplastic resin used for the base material layer, which will be described later.
  • the melting point of the heat seal resin (a) is preferably 115° C. or lower, more preferably 110° C. or lower, even more preferably 100° C. or lower, and 95° C. or lower. Especially preferred.
  • the heat seal resin (a) is easily melted during, for example, in-mold molding, and the adhesive strength is easily increased.
  • at least one preferably has a melting point within the above range, and more preferably all have melting points within the above range.
  • the melting point can be measured with a differential scanning calorimeter (DSC).
  • olefinic resins are preferable because they are excellent in moldability, low cost, transparency, ease of control of flexibility, and heat resistance or chemical resistance.
  • Olefin resins suitable as the heat seal resin (a) include, for example, homopolymers and copolymers of olefins, and copolymers formed from olefins and other comonomers.
  • Olefins include, for example, ethylene and propylene.
  • ethylene is preferable because it is easy to obtain an appropriate degree of crystallinity and easy to adjust the heat-sealing property. That is, the heat seal resin (a) is preferably an ethylene-based resin that is an ethylene homopolymer or copolymer.
  • the proportion of ethylene-derived structural units in the copolymer is preferably 80 mol% or more, more preferably 95 mol% or more, from the viewpoint of improving adhesion at low temperatures. 97 mol % or more is more preferable. In addition, the same ratio is less than 100 mol%. On the other hand, from the viewpoint of suppressing blocking, the proportion of structural units derived from monomers copolymerizable with ethylene in the ethylene resin is preferably 5 mol % or less, more preferably 3 mol % or less. Note that the same ratio exceeds 0 mol %.
  • the heat seal resin (a) is polyethylene
  • polyethylene for example, low or medium density polyethylene with a density of 0.900 to 0.940 g/cm 3
  • linear low density polyethylene with a density of 0.880 to 0.940 g/cm 3 Density polyethylene and the like are preferred.
  • low density, medium density or linear low density with a crystallinity measured by the X-ray method of 10 to 60% and a melt flow rate (190 ° C., 2.16 kg load) of 3 to 40 g / 10 minutes Density polyethylene is preferred.
  • a copolymer formed from ethylene and other comonomers as the heat seal resin (a).
  • Other comonomers used with ethylene include, for example, vinyl acetate, (meth)acrylic acid, alkyl (meth)acrylates, glycidyl (meth)acrylates, and the like.
  • acrylic acid or methacrylic acid may be a metal salt of Zn, Al, Li, K, Na or the like.
  • the heat seal resin (a) which is an ethylene copolymer includes an ethylene-methacrylic acid copolymer, an ethylene-vinyl acetate copolymer, an ethylene-glycidyl methacrylate copolymer, or an ethylene-glycidyl methacrylate-vinyl acetate copolymer.
  • Polymers are preferred, and ethylene-methacrylic acid copolymers are particularly preferred.
  • Water-soluble resin (c) examples include acrylic resins, acrylic silicone resins, vinyl resins, phenol resins, urethane resins, melamine resins, ketone resins, and the like. These may be modified with other resin components. One of these may be used alone, or two or more may be used in combination. A cross-linking agent may also be added to the water-soluble resin (c).
  • the heat seal layer (A) in the present invention contains, among the water-soluble resins (c), a (meth)acrylic acid-based copolymer having a cationic group. It is preferable to contain. If the heat seal resin (a) is water-soluble, the heat seal layer (A) can be formed by preparing a coating liquid using an aqueous solvent and applying the coating liquid. Process control becomes easier.
  • a cationic group refers to a group that is positively charged when dissolved in water.
  • the cationic group include ( ⁇ ) a group capable of forming a salt by binding to an anion, or ( ⁇ ) forming a cation by binding to a proton in the presence of an acid (e.g., acetic acid) and capable of binding to an acid anion. groups.
  • the group ( ⁇ ) include an ammonium base and a phosphonium base.
  • the group ( ⁇ ) include nitrogen compound groups such as amino groups.
  • An amino group is a group represented by the following formula (1), and R 1 and R 2 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkenyl group having 1 to 3 carbon atoms. obtain.
  • the cationic group constituting the ammonium base is a group represented by the following formula (2), and each of R 3 to R 5 is independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl group having 1 to 3 carbon atoms.
  • the amino group-containing (meth)acrylic acid-based copolymer preferably has a group represented by formula (2), among which R 3 is a hydrogen atom, R 4 and R More preferably, 5 is a cationic group constituting a tertiary ammonium base, each being an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 1 to 3 carbon atoms.
  • the structure of the "(meth)acrylic acid-based copolymer" portion in the "(meth)acrylic acid-based copolymer having a cationic group" contained in the heat seal layer (A) is the heat seal resin (a ) may be the same or different.
  • the mass ratio (a:c) of the heat seal resin (a) and the water-soluble resin (c) in the heat seal layer (A) is 70:30 to 45:55. If the mass ratio is within this range, even if the water-soluble resin (c) is blended in the heat seal layer (A), sufficient adhesive strength with the resin container can be obtained. Therefore, it is possible to adjust the adhesive strength of the laminate so that it is difficult to peel off from the resin container in normal use, but is easily peeled off from the resin container when subjected to high-temperature water treatment during recycling.
  • the mass ratio (a:c) of the heat seal resin (a) and the water-soluble resin (c) is more preferably 65:35 to 45:55.
  • the heat seal layer (A) can contain a tackifier.
  • a tackifier By containing a tackifier, it is easy to obtain not only high adhesive strength with molded articles such as polyethylene or polypropylene for direct blow molding, but also high adhesive strength with molded articles such as polyethylene terephthalate and polyester for stretch blow molding. Become.
  • tackifiers include hydrogenated petroleum resins, aromatic hydrocarbon resins, and aliphatic hydrocarbon resins.
  • Hydrogenated petroleum resins include, for example, partially hydrogenated petroleum resins.
  • aromatic hydrocarbon resins include terpene-based resins, rosin-based resins, and styrene-based resins.
  • a rosin-based tackifier is preferable from the viewpoint of improving the adhesive strength, particularly the adhesive strength to a polyester molded article.
  • the softening point of the tackifier is preferably 85°C or higher, more preferably 90°C or higher, and even more preferably 95°C or higher.
  • the softening point is preferably 110°C or lower, more preferably 105°C or lower.
  • the heat-sealing layer (A) can contain known additives as long as the heat-sealing property is not significantly impaired.
  • additives include waxes and antiblocking agents.
  • waxes include paraffin wax, microcrystalline wax, carnauba wax and Fischer-Tropsch wax.
  • the weight average molecular weight Mw of waxes is, for example, 5000 or less.
  • antiblocking agents include inorganic powders such as silica, talc and zeolite.
  • the content of these additives in the heat seal layer (A) is usually 0.01 to 5% by mass independently for each type of additive.
  • Heat seal layer (B) The heat seal layer (B) further imparts heat sealability to the laminate. Since not only the heat-sealing property of the heat-sealing layer (A) but also the heat-sealing property of the heat-sealing layer (B) is added, the adhesion strength of the laminate to the resin container can be further increased.
  • heat-sealing resin (b) examples include resins similar to those listed in the section ⁇ Heat-sealing resin (a)> in (Heat-sealing layer (A)).
  • the heat-sealing resin (b) is preferred as described above.
  • Polyethylene is particularly preferred because it is difficult for particles to form. Specifically, low or medium density polyethylene with a density of 0.900 to 0.940 g/cm 3 and linear low density polyethylene with a density of 0.880 to 0.940 g/cm 3 are preferred.
  • the heat seal resin (b) in the heat seal layer (B) may be the same as or different from the heat seal resin (a) in the heat seal layer (A).
  • the heat-seal layer (B) may be a film made of the heat-seal resin (b), or may be a film containing the heat-seal resin (b) with the following additives.
  • the heat seal layer (B) can contain known additives in the same manner as the heat seal layer (A) described above, as long as the effects of the invention are not impaired.
  • additives include waxes and antiblocking agents.
  • the content of these additives in the heat seal layer (B) is usually 0.01 to 5% by mass independently for each type of additive.
  • the base layer can impart mechanical strength to the laminate. As a result, sufficient stiffness can be obtained when the laminate is printed or the laminate is inserted into a mold, and excellent handleability can be obtained.
  • the base layer contains a thermoplastic resin.
  • thermoplastic resins include olefin resins, ester resins, amide resins, polyvinyl chloride resins, polystyrene resins, and polycarbonate resins.
  • the base material layer preferably contains an olefin resin or an ester resin as a thermoplastic resin, and more preferably contains an olefin resin.
  • olefinic resins examples include propylene-based resins and ethylene-based resins.
  • Propylene-based resins are preferred from the standpoint of laminate moldability and mechanical strength.
  • the propylene-based resin is not particularly limited as long as propylene is used as the main monomer.
  • examples include isotactic and syndiotactic polymers obtained by homopolymerizing propylene. It is also a copolymer of propylene, which is the main component, and ⁇ -olefins such as ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene. , propylene- ⁇ -olefin copolymers and the like can also be used.
  • the "main component” refers to a monomer that constitutes the copolymer at 50% by mass or more.
  • the copolymer may be a binary system or a multicomponent system of ternary system or higher, and may be a random copolymer or a block copolymer. Also, a propylene homopolymer and a propylene copolymer may be used in combination. Among these, a propylene homopolymer is preferable as a main component of the substrate layer because it is easy to handle.
  • Ethylene-based resins include, for example, high density polyethylene with a density of about 0.940 to 0.965 g/cm 3 , medium density polyethylene with a density of about 0.920 to 0.940 g/cm 3 , density of about 0.900 to 0 Linear low-density polyethylene of about 920 g/cm 3 , copolymers mainly composed of ethylene, etc., and copolymerized with ⁇ -olefins such as propylene, butene, hexene, heptene, octene, 4-methylpentene-1, Ethylene-alkyl (meth)acrylate copolymers, ethylene-(meth)acrylic acid copolymers or metal salts thereof (metals are zinc, aluminum, lithium, sodium, potassium, etc.), ethylene-cyclic olefin copolymers, etc. be done.
  • ⁇ -olefins such as propylene, butene, hexen
  • ester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.
  • amide-based resins include nylon-6, nylon-6,6, nylon-6,10, and nylon-6,12.
  • the content of the thermoplastic resin in the substrate layer is preferably 50% by mass or more, more preferably 70% by mass or more. If the content is 50% by mass or more, the mechanical strength of the base material layer is likely to be improved. On the other hand, there is no particular upper limit for the content of the thermoplastic resin, and it may be 100% by mass.
  • the base material layer may contain fillers, additives, etc., which will be described later, within the range that does not affect the strength or moldability of the laminate. good.
  • the base material layer can contain a filler.
  • a filler facilitates the formation of pores with the filler as a nucleus inside the base material layer, and can increase the whiteness or opacity.
  • Examples of fillers that can be used in the base material layer include inorganic fillers and organic fillers.
  • inorganic fillers include heavy calcium carbonate, light calcium carbonate, calcined clay, silica, diatomaceous earth, clay, talc, titanium oxide such as rutile-type titanium dioxide, barium sulfate, aluminum sulfate, zinc oxide, magnesium oxide, mica, and celery.
  • Inorganic particles such as site, bentonite, sepiolite, vermiculite, dolomite, wollastonite, or glass fibers.
  • heavy calcium carbonate, clay or diatomaceous earth is preferable because of its good pore-formability and low cost.
  • the surface of the inorganic filler may be surface-treated with a surface-treating agent such as fatty acid.
  • organic filler examples include resins incompatible with the thermoplastic resin contained in the base material layer.
  • Organic particles such as phthalate, polybutylene terephthalate, polyamide, polycarbonate, polystyrene, cyclic olefin homopolymer, ethylene-cyclic olefin copolymer, polyethylene sulfide, polyimide, polymethacrylate, polyether ether ketone, polyphenylene sulfide, or melamine resin mentioned.
  • One of the above inorganic fillers or organic fillers can be used alone, or two or more thereof can be used in combination.
  • the filler content in the substrate layer is preferably 10% by mass or more, more preferably 15% by mass or more.
  • the content of the filler in the base material layer is preferably 70% by mass or less, more preferably 60% by mass or less, and 50% by mass or less. More preferred.
  • the content of the filler in the substrate layer may be less than 10% by mass, or may be 0% by mass.
  • the average particle size of the inorganic filler or organic filler is preferably 0.01 ⁇ m or more, more preferably 0.05 ⁇ m or more, and even more preferably 0.1 ⁇ m or more, from the viewpoint of ease of forming pores. From the viewpoint of imparting mechanical strength such as tear resistance to the laminate, the average particle size of the inorganic filler or organic filler is preferably 15 ⁇ m or less, more preferably 5 ⁇ m or less, and even more preferably 2 ⁇ m or less.
  • the average particle size of the inorganic filler is measured by a particle measuring device, for example, a laser diffraction particle size distribution measuring device (Microtrac, manufactured by Nikkiso Co., Ltd.), and the volume average particle size corresponding to 50% of the cumulative volume (cumulative 50% particle size ) D50.
  • the average particle size of the organic filler is the average dispersed particle size when dispersed in the thermoplastic resin by melt-kneading and dispersion.
  • the average dispersed particle size can be obtained by observing the cut surface of the thermoplastic resin film containing the organic filler with an electron microscope, measuring the maximum size of at least 10 particles, and calculating the average value.
  • the porosity which indicates the ratio of pores in the layer, is preferably 10% or more, more preferably 20% or more, from the viewpoint of obtaining opacity. Preferably, it is more preferably 30% or more. From the viewpoint of maintaining mechanical strength, the porosity is preferably 70% or less, more preferably 55% or less, and even more preferably 40% or less. On the other hand, from the viewpoint of increasing the transparency of the substrate layer, the porosity may be less than 10% or may be 0%. The porosity can be obtained from the ratio of the area occupied by pores in a certain region of the cross section of the sample observed with an electron microscope.
  • the filler content or porosity can be selected according to the transparency, whiteness, etc. required for the laminate.
  • ⁇ Other additives Antioxidants such as sterically hindered phenols, phosphorus, amines, and sulfur; light stabilizers such as sterically hindered amines, benzotriazoles, and benzophenones; and dispersants. , or an antistatic agent.
  • the content of each component is preferably 0.001 to 1% by mass relative to the total mass of each component constituting the substrate layer.
  • the specific gravity of the base material layer is preferably 1.0 or less. This makes it easier for the laminate separated from the compact to float when immersed in water in the high-temperature water treatment. Since the specific gravity of the resin in the molded body is generally greater than 1.0, the molded body and laminate are easily separated, and the label is easily removed.
  • the surface of the base material layer opposite to the surface facing the heat seal layer may be surface-treated in order to increase the adhesion to the printed layer.
  • the printed layer is provided by printing characters, drawings, etc. on the surface of the substrate layer opposite to the surface facing the heat seal layer.
  • a printing layer is a layer formed by a printing ink component. From the viewpoint of enhancing adhesion with ink, a print-receiving layer may be provided on the surface of the base material layer, and a print layer may be laminated on this print-receiving layer.
  • the print-receiving layer can be formed, for example, by coating the surface of the substrate layer with a coating agent.
  • the thickness of the heat seal layer (A) can be expressed as the mass per unit area of the heat seal layer (A). From the viewpoint of recyclability, the thickness of the heat seal layer (A) is preferably 0.01 g/m 2 or more, more preferably 0.03 g/m 2 or more. The thickness of the heat seal layer (A) is preferably 5 g/m 2 or less, more preferably 1 g/m 2 or less, and 0.5 g/m 2 or less, from the viewpoint of adhesive strength. It is even more preferable to have
  • the thickness of the heat seal layer (A) is preferably 0.01 ⁇ m or more, more preferably 0.03 ⁇ m or more, from the viewpoint of recyclability.
  • the thickness of the heat seal layer (A) is preferably 5 ⁇ m or less, more preferably 1 ⁇ m or less, and even more preferably 0.5 ⁇ m or less, from the viewpoint of adhesive strength.
  • the thickness of the heat seal layer (B) is preferably 1 ⁇ m or more, more preferably 2 ⁇ m or more. From the viewpoint of suppressing cohesive failure inside the heat seal layer (B), the thickness of the heat seal layer (B) is preferably 35 ⁇ m or less, more preferably 25 ⁇ m or less, even more preferably 15 ⁇ m or less, and even more preferably 5 ⁇ m or less. It is preferably 3 ⁇ m or less, and particularly preferably 3 ⁇ m or less.
  • the thicknesses of the heat seal layers (A) and (B) can be measured by cross-sectional observation with a scanning electron microscope as described in Examples.
  • the thickness of the base material layer is preferably 20 ⁇ m or more, more preferably 40 ⁇ m or more.
  • the thickness of the substrate layer is preferably 200 ⁇ m or less, more preferably 150 ⁇ m or less.
  • the method for producing the laminate of the present invention is not particularly limited.
  • the laminate of the present invention can be produced by forming films of each layer and laminating them.
  • Film forming methods for each layer include extrusion molding (cast molding) with a T-die, inflation molding with an O-die, and calender molding with a rolling roll.
  • Methods for laminating each film include a coextrusion method, an extrusion lamination method, a coating method, and the like, and these can be combined.
  • a resin composition for each layer is supplied to a multilayer die, and these are laminated and extruded within the multilayer die.
  • lamination is performed in parallel with film formation.
  • a film formed by extruding a molten resin composition for another layer is laminated on a previously formed film, and the laminate is nipped with rolls while being cooled.
  • film formation and lamination are performed in separate steps.
  • another film is formed and laminated by applying a solution, emulsion or dispersion of a resin composition for another layer onto a previously formed film and drying it.
  • Each layer may be a non-stretched film or a stretched film. Also, each layer may be stretched individually before lamination, or may be stretched together after lamination. After the unstretched layer and the stretched layer are laminated, they may be stretched again.
  • Stretching methods include, for example, a longitudinal stretching method using a difference in circumferential speed between rolls, a transverse stretching method using a tenter oven, a sequential biaxial stretching method combining these methods, a rolling method, and a simultaneous two-stretching method using a combination of a tenter oven and a pantograph.
  • An axial stretching method and a simultaneous biaxial stretching method using a combination of a tenter oven and a linear motor can be used.
  • a simultaneous biaxial stretching (inflation molding) method can also be used, in which a circular die connected to a screw extruder is used to extrude a molten resin into a tubular shape, and then air is blown into the tubular shape.
  • the stretching temperature when stretching is preferably in the range of the glass transition point or higher of the thermoplastic resin.
  • the stretching temperature should be above the glass transition point of the non-crystalline portion of the thermoplastic resin and below the melting point of the crystalline portion of the thermoplastic resin. is preferred, and specifically, a temperature lower than the melting point of the thermoplastic resin by 2 to 60°C is preferred.
  • the stretching speed is not particularly limited, but from the viewpoint of stable stretching molding, it is preferably in the range of 20 to 350 m/min.
  • the draw ratio can also be appropriately determined in consideration of the properties of the thermoplastic resin to be used.
  • the draw ratio is usually about 1.2 times or more, preferably about 2 times or more. , is usually 12 times or less, preferably 10 times or less.
  • the draw ratio in area draw ratio is usually 1.5 times or more, preferably 10 times or more, while it is usually 60 times or less, preferably 50 times or less. . If the draw ratio is within the above range, there is a tendency that the film is less likely to break and that stable draw molding can be achieved. Further, when the substrate layer is white or opaque, the target porosity is obtained, and the opacity is easily improved.
  • each layer is subjected to surface treatment to activate the surface in order to enhance adhesion to adjacent layers.
  • Surface treatments include corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment, ozone treatment, and the like, and these treatments can be combined. Among them, corona discharge treatment or flame treatment is preferable, and corona discharge treatment is more preferable.
  • the amount of discharge when performing corona discharge treatment is preferably 600 J/m 2 (10 W ⁇ min/m 2 ) or more, more preferably 1,200 J/m 2 (20 W ⁇ min/m 2 ) or more. . Also, the discharge amount is preferably 12,000 J/m 2 (200 W ⁇ min/m 2 ) or less, more preferably 10,800 J/m 2 (180 W ⁇ min/m 2 ) or less.
  • the amount of discharge when flame treatment is performed is preferably 8,000 J/m 2 or more, more preferably 20,000 J/m 2 or more, and the discharge amount is preferably 200,000 J/m 2 . or less, more preferably 100,000 J/m 2 or less.
  • the printed layer can be formed by printing on the surface of the substrate layer opposite to the surface facing the heat seal layer (A).
  • the printed information includes the product name, logo, manufacturer, sales company name, usage method, barcode, and the like. includes various colors and patterns, images, and the like.
  • the printing method is not particularly limited, and examples thereof include gravure printing, offset printing, flexographic printing, seal printing, and screen printing.
  • the laminate of the present invention can be used for decorating a molded body (adherend) by vacuum molding, air pressure molding, vacuum pressure molding (TOM molding), insert molding, etc., using heat sealability, sealant materials, It can be used for packaging materials, labels and the like. Among them, it is preferable to use it as a heat-sensitive label from the viewpoint of taking advantage of the characteristics of the present invention. Even when the laminate of the present invention is used for applications other than labels, such as the above-described decorative application, it can be peeled off from the adherend by high-temperature water treatment in the same way as when used as a label for a resin container. is.
  • the thermal label of the present invention includes the laminate of the present invention described above.
  • the heat-sensitive label of the present invention can be adhered to a resin-made adherend via the heat-seal layer (A) melted by heating.
  • the in-mold label of the present invention comprises the heat-sensitive label of the present invention described above.
  • the in-mold label of the present invention can obtain good adhesive strength not only to direct blow molded olefin resin containers but also to stretch blow molded ester resin containers. Therefore, the in-mold label of the present invention can be preferably used even for an ester-based resin container, which is usually difficult to obtain adhesive strength with a label.
  • the in-mold label of the present invention can be adhered not only to a resin container but also to a molded product other than a container molded using a mold.
  • the in-mold label of the present invention is adhered to the outer surface of the resin container via the heat seal layer (A).
  • A heat seal layer
  • the in-mold label of the present invention is used for in-mold molding, for example, after the label is placed in contact with the inner surface of the lower female mold, which is a differential pressure molding mold, the printed surface of the label is in contact with the inner wall of the mold by suction. fixed to Next, a melted resin sheet, which is the material of the molded body, is introduced above the lower female mold and subjected to differential pressure molding by a conventional method to produce a labeled molded body in which the label is integrally adhered to the outer wall of the molded body.
  • Both vacuum forming and pressure forming can be employed for the differential pressure forming, but in general, differential pressure forming using both of them together and using a plug assist is preferred.
  • the in-mold label of the present invention can be produced by direct blow molding in which a parison of molten resin is pressed against the inner wall of the mold by compressed air, stretch blow molding using a preform, or injection of molten resin into the mold by an injection device and cooling and solidification. It can be suitably used for injection molding.
  • the heat-sensitive label of the present invention is suitable for direct blow molding or injection molding. In these molding methods, since the resin container is molded in a mold to which the label is fixed, there is no deformation of the label, the adhesive strength between the molded product and the label is strong, there is no blistering, and the label can be decorated. A molded article having a good appearance can be obtained.
  • the material of the resin container to which the in-mold label of the present invention can be applied is not particularly limited.
  • the color of the resin container may be transparent, a natural color that does not contain a colorant such as a pigment or a dye, or an opaque color due to a colorant or coloring.
  • resin containers include bottles and boxes.
  • the cross-sectional shape of the body of the resin container may be a perfect circle, an ellipse, or a rectangle. If the cross-sectional shape of the fuselage is rectangular, it is preferred that the corners have curvature. From the viewpoint of strength, the cross section of the body is preferably a perfect circle or an ellipse close to a perfect circle, more preferably a perfect circle.
  • Table 1 shows a list of materials used to manufacture the thermal labels of Examples and Comparative Examples.
  • Example 1 As a material for the substrate layer, 100 parts by mass of propylene homopolymer (MA) (trade name: Novatec PP MA4, manufactured by Japan Polypropylene Corporation, melting point (JIS-K7121): 167° C.) was prepared. This was melt-kneaded in an extruder heated to 210° C. and supplied to a two-layer coextrusion die.
  • MA propylene homopolymer
  • heat seal resin (b) which is the material of the heat seal layer (B)
  • metallocene low density polyethylene (KS) trade name: Kernel KS571, manufactured by Japan Polyethylene Co., Ltd., MFR: 12 g/10 minutes, melting point: 100°C, density: 0.907 g/cm 3 ) 100 parts by mass were prepared. This was melted in an extruder heated to 210° C. and supplied to the same two-layer coextrusion die as the substrate layer.
  • the material for the substrate layer and the material for the heat seal layer (B) were laminated in a two-layer co-extrusion die and extruded from the same die as a two-layer sheet. This was cooled by a cooling device to obtain a non-stretched sheet having a two-layer structure.
  • the unstretched sheet thus obtained was heated to 150° C. and stretched 5 times in the machine direction using the difference in peripheral speed between a plurality of roll groups. After cooling to 60° C., the film was heated again to 150° C. and stretched 8 times in the transverse direction using a tenter. Then, it was annealed at 160° C. and cooled to 60° C. to obtain a transparent biaxially stretched film having a two-layer structure.
  • the film After slitting the tabs of the biaxially stretched film, the film was led to a corona discharge treatment apparatus, and both surfaces of the substrate layer side and the heat seal layer (B) side were subjected to corona discharge treatment at 50 W/m 2 .
  • the total thickness of the obtained biaxially stretched film was 70 ⁇ m.
  • the thickness of the substrate layer was 68 ⁇ m
  • the thickness of the heat seal layer (B) was 2 ⁇ m.
  • the water-soluble resin (c) the methacrylic acid-based copolymer (Ac) having a polar group obtained in Preparation Example 1
  • the heat seal resin (a) the ethylene-methacrylic acid copolymer (EMAA) ( Trade name: Nucrel N035C, manufactured by Mitsui-Dow Polychemicals, melting point 86°C) was diluted with deionized water to prepare a coating solution.
  • the solid content concentration of the coating liquid was adjusted to 10% by mass, and the mass ratio of the methacrylic acid-based copolymer (Ac) and the ethylene-methacrylic acid copolymer (EMAA) in the coating liquid was adjusted to 40:6.
  • the prepared coating solution was applied onto the surface of the biaxially stretched film on the side of the heat seal layer (B) using a gravure coater. It was dried in an oven at 80° C. to form a heat-seal layer (A), and a three-layer laminate was obtained as a thermosensitive label of Example 1.
  • the thickness of the heat seal layer (A) of the thermosensitive label of Example 1 was 0.05 g/m 2 (0.05 ⁇ m).
  • Table 2 shows the contents (parts by mass) of the methacrylic acid-based copolymer (Ac) and the ethylene-methacrylic acid copolymer (EMAA) in the heat seal layer (A).
  • Example 2 and Comparative Examples 1 to 3 Thermal labels of Example 2 and Comparative Examples 1 to 3 were produced in the same manner as in Example 1, except that the composition of the heat seal layer (A) was changed as shown in Table 2.
  • Example 4 In Example 1, except that the composition of the heat seal layer (A) was changed as shown in Table 2, the base layer/heat seal layer (B)/heat seal layer (A) was prepared in the same manner as in Example 1. A three layer laminate was produced. Then, EMAA dissolved in toluene was applied to the surface of the heat seal layer (A) using a gravure coater. It was dried in an oven at 80°C to form a heat seal layer (Z) having an EMAA content (parts by mass) as shown in Table 2, and a four-layer laminate was obtained as a thermal label of Comparative Example 4. rice field.
  • the thickness (total thickness) of the thermal label was measured in accordance with JIS K7130:1999 using a constant pressure thickness gauge (product name: PG-01J, manufactured by Teclock). Also, the thickness of each layer in the thermal label was determined as follows. The sample to be measured is cooled to a temperature of -60 ° C or less with liquid nitrogen, and a razor blade (trade name: Proline blade, manufactured by Sick Japan) is applied at right angles to the sample placed on the glass plate and cut. , a sample for cross-sectional observation was prepared.
  • the cross section of the obtained sample was observed using a scanning electron microscope (product name: JSM-6490, manufactured by JEOL Ltd.), and the boundary line for each thermoplastic resin composition in each layer was determined from the appearance. It was obtained by multiplying the measured total thickness of the thermal label by the observed thickness ratio of each layer.
  • Labeled containers were produced using the heat-sensitive labels of each example and comparative example in the following manner, and the adhesive strength and recyclability of each heat-sensitive label were evaluated.
  • the thermal label was cut into sheets and punched into a rectangle with a long side of 8 cm and a short side of 6 cm to prepare a sample for evaluation.
  • the sample was charged using an electrostatic charging device, placed inside a molding die of a stretch blow molding machine (manufactured by Nissei ASB, machine name: ASB-70DPH), and clamped. Installation was performed so that the base material layer was in contact with the mold.
  • the heat-sensitive label was placed in the mold such that the long side of the label was parallel to the circumferential direction of the body of the square prism-shaped resin container. The mold was controlled so that the surface temperature on the cavity side was within the range of 20 to 45°C.
  • a preform of polyethylene terephthalate resin was preheated to 100°C. This preform was introduced into a mold and stretch blow molded for 1 second under a blow pressure of 5 to 40 kg/cm 2 . After cooling to 50° C. for 15 seconds, the mold was opened to obtain a PET container with a heat-sensitive label having a rectangular body portion with a height of 12 cm and a side of about 7 cm.
  • ⁇ Adhesion strength> The obtained labeled PET container was stored for 2 days under an environment of a temperature of 23° C. and a relative humidity of 50%. Next, the labeled portion of the PET container with the label and the container body are cut together with a cutter, and the length is 12 cm with the circumferential direction of the container body as the longitudinal direction (8 cm for the label-attached portion, non-labeled). Samples of 4 cm pasted area) and 1.5 cm wide (full width label pasted) were taken.
  • the label-attached portion of the obtained sample was carefully peeled off from the label-unattached portion, and about 1 cm was peeled off to form a grasping margin.
  • a gripping margin and a PET film (thickness: 50 ⁇ m) with a width of 1.5 cm were overlapped and adhered with an adhesive to form a gripping margin portion on the label side, and a sample for adhesion strength measurement was produced.
  • Table 2 below shows the composition and evaluation results of each thermal label.
  • the thermal labels of Examples 1 and 2 both have sufficient adhesive strength and excellent recyclability.
  • the thermal labels of Comparative Examples 1 and 3 had high adhesive strength, their recyclability was low and the number of peeled labels was small.
  • the heat-sensitive label of Comparative Example 2 had good recyclability, but weak adhesive strength.
  • the heat-sensitive label of Comparative Example 4 had high adhesive strength, but peeling was incomplete in the recyclability evaluation, and the label peeled off at the heat-seal layer (A), leaving the heat-seal layer (Z) on the surface of the PET container.

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PCT/JP2022/031710 2021-08-27 2022-08-23 積層体、感熱ラベル、インモールドラベル及びラベル付き容器 Ceased WO2023027067A1 (ja)

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WO2026054085A1 (ja) * 2024-09-09 2026-03-12 株式会社ユポ・コーポレーション 積層体

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Publication number Priority date Publication date Assignee Title
JPH07244462A (ja) * 1994-03-03 1995-09-19 Fuji Seal Co Ltd 感熱接着ラベル
JPH1185034A (ja) * 1997-09-11 1999-03-30 Dainippon Printing Co Ltd ラベル
WO2006054725A1 (ja) * 2004-11-18 2006-05-26 Yupo Corporation ラベル付きインモールド成型体およびインモールド用ラベル
WO2020067327A1 (ja) * 2018-09-28 2020-04-02 株式会社ユポ・コーポレーション インモールドラベル及びインモールドラベル付き容器
WO2021193852A1 (ja) * 2020-03-27 2021-09-30 株式会社ユポ・コーポレーション 感熱ラベル

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JP5476951B2 (ja) 2009-12-02 2014-04-23 東洋アドレ株式会社 ロールシュリンクラベル及びラベル付き容器
JP7289011B2 (ja) * 2020-03-27 2023-06-08 株式会社ユポ・コーポレーション 感熱ラベル及び感熱ラベルの製造方法

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Publication number Priority date Publication date Assignee Title
JPH07244462A (ja) * 1994-03-03 1995-09-19 Fuji Seal Co Ltd 感熱接着ラベル
JPH1185034A (ja) * 1997-09-11 1999-03-30 Dainippon Printing Co Ltd ラベル
WO2006054725A1 (ja) * 2004-11-18 2006-05-26 Yupo Corporation ラベル付きインモールド成型体およびインモールド用ラベル
WO2020067327A1 (ja) * 2018-09-28 2020-04-02 株式会社ユポ・コーポレーション インモールドラベル及びインモールドラベル付き容器
WO2021193852A1 (ja) * 2020-03-27 2021-09-30 株式会社ユポ・コーポレーション 感熱ラベル

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2026054085A1 (ja) * 2024-09-09 2026-03-12 株式会社ユポ・コーポレーション 積層体

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