Packaging paper and packaging body

Abstract

To provide packaging paper which has a reduced load on the environment, has excellent visibility when formed into a packaging body, has excellent feeding property (resistance to breaking even when an edge is pulled at a desired speed) when packaging with machines, and also has heat sealability; and a packaging body that is formed of the packaging paper.SOLUTION: Packaging paper has a heat seal layer on a paper substrate, wherein the paper substrate has a basis weight of 60 g / m2 or less; the content of the paper substrate in the packaging paper is 50 mass% or more; the opacity of the packaging paper is 80% or less; and the tensile strength in the longitudinal direction of the packaging paper is 1.2 kN / m or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to wrapping paper and a package.

Background Art

[0002] In recent years, the problem of plastic waste has been worsening globally. To improve the global environment, the reduction and replacement of plastic in packaging materials have been promoted, and there is a growing trend to replace plastic packaging with paper-based packaging. However, paper has the problem of being weaker and more prone to tearing compared to plastic materials. Patent Document 1 aims to provide a base paper for packaging a sealed container that has high strength against bending, excellent impact resistance, and retains strength that is not easily torn even by impacts during distribution after packaging the contents. The base paper for packaging a sealed container mainly composed of pulp, wherein 70% by mass or more of the pulp is softwood pulp, contains a dry paper strength enhancer and a wet paper strength enhancer, and carboxymethyl cellulose is applied to at least one surface of the base paper. A base paper for packaging a sealed container is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although the base paper for packaging described in Patent Document 1 has high strength and can firmly hold the contents, it is difficult to visually grasp the contents, that is, it has poor visibility and there is room for improvement. An object of the present invention is to provide wrapping paper that reduces the environmental load, has excellent visibility when formed into a package, has excellent feedability (difficult to tear even when the edge is pulled at a desired speed) when packaging using a machine, has heat sealability, and a package using the wrapping paper.

Means for Solving the Problems

[0005] The inventors of the present invention have found that, in the wrapping paper having a heat-sealing layer, by setting the basis weight of the paper base material to a specific value or less, the content of the paper base material in the wrapping paper to a specific value or more, the opacity to a specific value or less, and the tensile strength in the longitudinal direction to a specific value or more, the above problems can be solved. That is, the present invention relates to the following <1> to <7>. <1> A wrapping paper having a heat-sealing layer on a paper base material, wherein the basis weight of the paper base material is 60 g / m 2 or less, the content of the paper base material in the wrapping paper is 50% by mass or more, the opacity of the wrapping paper is 80% or less, and the tensile strength in the longitudinal direction of the wrapping paper is 1.2 kN / m or more. <2> The wrapping paper according to <1>, having a thickness of 90 μm or less. <3> The wrapping paper according to <1> or <2>, having a basis weight of 75 g / m 2 or less. <4> The wrapping paper according to any one of <1> to <3>, wherein the raw material pulp of the paper base material contains hardwood sun-dried kraft pulp, and the content of the hardwood sun-dried kraft pulp in the raw material pulp is 85% by mass or more. <5> The wrapping paper according to any one of <1> to <4>, wherein the paper base material and the heat-sealing layer are directly laminated. <6> The heat-sealing layer is a laminate layer having a basis weight of less than 20 g / m 2 or a coating layer having a basis weight of less than 3 g / m 2 The wrapping paper according to any one of <1> to <5>. <7> A package having a lid material and a bottom material having a recess, and capable of accommodating and sealing an object to be accommodated in the recess by heat-sealing the lid material and the bottom material, wherein the lid material and the bottom material are made of the wrapping paper according to any one of <1> to <6>.

Advantages of the Invention

[0006] According to the present invention, there is provided a wrapping paper that reduces the environmental load, has excellent visibility when formed into a package, has excellent paper feeding property when packaging using a machine, and has heat sealability, and a package formed using the wrapping paper.

Brief Description of the Drawings

[0007]

Figure 1

Embodiments for Carrying Out the Invention

[0008] [Wrapping Paper] The wrapping paper of this embodiment is a wrapping paper having a heat seal layer on a paper base material, the basis weight of the paper base material is 60 g / m 2 or less, the content of the paper base material in the wrapping paper is 50% by mass or more, the opacity of the wrapping paper is 80% or less, and the tensile strength in the longitudinal direction of the wrapping paper is 1.2 kN / m or more. According to the wrapping paper of this embodiment, there is provided a wrapping paper that reduces the environmental load, has excellent visibility when formed into a package, has excellent paper feeding property when packaging using a machine, and has heat sealability. The reason for obtaining the above effects is that since the content of the paper base material in the wrapping paper is 50% or more, the content of the plastic material in the wrapping paper becomes 50% or less, and the environmental load is reduced. Also, since the basis weight of the paper base material is 60 g / m 2 or less and the content of the paper base material in the wrapping paper is 50% by mass or more and the tensile strength in the longitudinal direction is 1.2 kN / m or more, it is considered that the wrapping paper has appropriate strength and excellent paper feeding property. Furthermore, since the opacity is 80% or less, it is considered to have excellent visibility. Note that the reason for obtaining the above effects is not limited to this. Also, according to the wrapping paper of this embodiment, the raw material pulp constituting the paper base material is beaten so that the opacity becomes 80% or less, and the basis weight of the paper base material is 60 g / m 2By doing the following, unevenness of the paper base material is suppressed, and when heat-sealing, the entire paper base material can be uniformly heated. Therefore, it is considered possible to form a heat-sealing layer with a basis weight smaller than that of the conventional heat-sealing layer. Hereinafter, the present invention will be described in more detail.

[0009] In this specification, the numerical range represented by "X to Y" means a numerical range including X as the lower limit value and Y as the upper limit value. When the numerical ranges are described stepwise, the upper and lower limits of each numerical range can be arbitrarily combined. Further, in this specification, unless otherwise specified, measurements such as operations and physical properties are performed under the conditions of room temperature (20 to 25°C) / relative humidity 40 to 50%RH. Also, "(meth)acrylic" is a general term including both acrylic and methacrylic. Also, the longitudinal direction of the wrapping paper and the paper base material means the paper-making direction (MD) in the paper base material, and the transverse direction means the direction (CD) orthogonal to the paper-making direction.

[0010] <Paper base material> The wrapping paper of the present embodiment has a heat-sealing layer on the paper base material. Note that the paper base material may be formed of a single layer or multiple layers, and is not particularly limited. The paper base material is a sheet mainly composed of pulp, and the base paper obtained by papermaking a paper stock containing raw material pulp, fillers, various auxiliaries, etc. as it is, or on at least one surface of the base paper, a blocking layer, an ink receiving layer, a water-resistant layer, an oil-resistant layer, a water vapor barrier layer, a gas barrier layer, etc. One or more functional layers formed can be used.

[0011] (Raw material pulp) The pulp constituting the paper base material is not particularly limited, and known pulp can be used. Specifically, unbleached pulp such as hardwood unbleached kraft pulp (LUKP) and softwood unbleached kraft pulp (NUKP); chemical pulp such as hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP); groundwood pulp (GP), pressurized groundwood pulp (PGW), refiner mechanical pulp (RMP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), chemimechanical pulp (CMP), chemiground pulp (CGP), etc. Mechanical pulp; waste paper pulp; non-wood fiber pulp such as kenaf, bagasse, bamboo, cotton, etc.; synthetic pulp, etc. These pulps may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of hardwood unbleached kraft pulp (LUKP), softwood unbleached kraft pulp (NUKP), hardwood bleached kraft pulp (LBKP), and softwood bleached kraft pulp (NBKP) is preferable, and at least one selected from the group consisting of hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP) is more preferable, and hardwood bleached kraft pulp (LBKP) is even more preferable.

[0012] The main component of the pulp constituting the paper base material used for the wrapping paper of this embodiment is preferably hardwood pulp, and more preferably hardwood bleached kraft pulp (LBKP). "The main component of the pulp constituting the paper base material is hardwood pulp (or hardwood bleached kraft pulp)" means that the content of hardwood pulp (or hardwood bleached kraft pulp) in the pulp constituting the paper base material exceeds 50% by mass. The content of hardwood pulp (or hardwood bleached kraft pulp) is preferably 85% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and even more preferably 100% by mass. Hardwood pulp has a shorter average fiber length than softwood pulp. By using a paper base material using hardwood pulp as the raw material pulp, a wrapping paper having a desired tensile strength can be obtained, and it is preferable because of excellent paper feeding properties. In addition, by using hardwood pulp, preferably hardwood kraft pulp, as the raw material pulp, the average fiber length of the pulp constituting the paper base material tends to be short. As a result, paper unevenness is suppressed, and a paper base material with better surface uniformity can be obtained. In order to form a heat-sealing layer on the paper base material with high surface uniformity, even if a heat-sealing layer with a lower basis weight is formed, a uniform heat-sealing layer can be formed, and the formation of a heat-sealing layer with a lower basis weight also has the effect of imparting good heat-sealing properties.

[0013] That is, the raw material pulp preferably contains hardwood kraft pulp (LBKP) and, if necessary, softwood kraft pulp (NBKP). The total content of hardwood kraft pulp and softwood kraft pulp in the raw material pulp is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass. Also, the mass ratio (NBKP / LBKP) of softwood kraft pulp (NBKP) to hardwood kraft pulp (LBKP) in the raw material pulp is preferably 0 / 100 or more and 15 / 85 or less, more preferably 10 / 90 or less, and still more preferably 5 / 95 or less.

[0014] (Canadian Standard Freeness) The beating degree of the raw material pulp is not particularly limited, but from the perspective of obtaining wrapping paper with desired Clark stiffness, puncture strength, and length-weighted average fiber length, as the Canadian Standard Freeness (CSF), it is preferably 300 mL or more and 700 mL or less, more preferably 350 mL or more, still more preferably 380 mL or more, and more preferably 600 mL or less, still more preferably 500 mL or less, and even more preferably 450 mL or less. When the CSF of the raw material pulp is within the above range, the smoothness of the paper base material surface becomes good, and even if the basis weight is small, a uniform heat-sealing layer tends to be obtained, which is preferable. CSF is measured in accordance with JIS P 8121-2:2012 "Pulp - Freeness test method - Part 2: Canadian Standard Freeness method".

[0015] (Grammage) In this embodiment, the grammage of the paper substrate is 60 g / m 2 or less. Preferably 55 g / m 2 or less, more preferably 45 g / m 2 or less, even more preferably 36 g / m 2 or less, still more preferably 32 g / m 2 or less. Also, the lower limit is not particularly limited, but from the viewpoint of obtaining a desired tensile strength, it is preferably 10 g / m 2 or more, more preferably 15 g / m 2 or more, even more preferably 17 g / m 2 or more. When the grammage of the paper substrate is within the above range, it is preferable because a wrapping paper with excellent visibility and excellent paper feeding property can be obtained. The grammage of the paper substrate is measured in accordance with JIS P 8124:2011. When measuring the grammage of the paper substrate from the wrapping paper, the thickness of the heat seal layer may be measured with a scanning electron microscope (SEM), and the grammage of the paper substrate may be calculated by calculating the grammage of the heat seal layer from the results of the component analysis of the heat seal layer.

[0016] (Thickness) The thickness of the paper substrate is preferably 20 μm or more and 85 μm or less, more preferably 22 μm or more, even more preferably 25 μm or more, and more preferably 75 μm or less, even more preferably 60 μm or less, still more preferably 50 μm or less, and most preferably 45 μm or less. When the thickness of the paper substrate is within the above range, it is preferable because a desired tensile strength can be obtained, and a wrapping paper with excellent visibility and excellent paper feeding property can be obtained. The thickness of the paper substrate is measured in accordance with JIS P 8118:2014, and specifically, it is measured by the method described in the examples.

[0017] (Density) The density of the paper substrate is preferably 0.3 g / cm 3 or more and 1.0 g / cm 3 or less, more preferably 0.5 g / cm 3More preferably, it is 0.6 g / cm 3 or more, and more preferably 0.9 g / cm 3 or less, more preferably 0.8 g / cm 3 or less. When the density of the paper base material is within the above range, a desired tensile strength can be obtained, and a wrapping paper excellent in visibility and paper feeding property can be obtained, which is preferable. The density of the paper base material is calculated from the basis weight and thickness of the paper base material obtained by the above-described measurement method.

[0018] (Optional component) The paper base material may contain, if necessary, for example, internal additives such as anionic, cationic or amphoteric retention aids, drainage improvers, dry paper strength enhancers, wet paper strength enhancers, sizing agents, fixing agents, fillers, etc., and optional components such as water resistance agents, dyes, fluorescent brighteners, etc.

[0019] Examples of the dry paper strength enhancer include cationized starch, polyacrylamide, carboxymethyl cellulose, etc. The content of the dry paper strength enhancer is not particularly limited, but is preferably 3.0 parts by mass or less with respect to 100 parts by mass of the raw material pulp (dry mass).

[0020] Examples of the wet paper strength enhancer include polyamide polyamine epichlorohydrin, urea formaldehyde resin, melamine formaldehyde resin, etc. The content of the wet paper strength enhancer is not particularly limited, but is preferably 3.0 parts by mass or less with respect to 100 parts by mass of the raw material pulp (dry mass).

[0021] Examples of the sizing agent include internal sizing agents such as rosin sizing agent, synthetic sizing agent (for example, alkyl ketene dimer), petroleum resin-based sizing agent, and surface sizing agents such as styrene / acrylic acid copolymer and styrene / methacrylic acid copolymer. The content of the sizing agent is not particularly limited, but is preferably 3.0 parts by mass or less per 100 parts by mass of the raw material pulp (dry mass).

[0022] Examples of the fixing agent include vanadium sulfate and polyethyleneimine. The content of the fixing agent is not particularly limited, but is preferably 3.0% by mass or less per raw material pulp (dry mass).

[0023] Examples of the filler include inorganic fillers such as talc, kaolin, calcined kaolin, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, white carbon, bentonite, zeolite, sericite, and smectite, and organic fillers such as acrylic resins and vinylidene chloride resins.

[0024] <Method for manufacturing paper substrate> The method for manufacturing the paper substrate preferably includes a step of papermaking a slurry containing the above raw material pulp. The papermaking method is not particularly limited, and examples thereof include an acidic papermaking method in which papermaking is performed at a pH of around 4.5, and a neutral papermaking method in which papermaking is performed at a pH of about 6 to about 9. In the papermaking step, papermaking agents such as a pH adjuster, an antifoaming agent, a pitch control agent, and a slime control agent can be appropriately added as necessary. The papermaking machine is not particularly limited, and examples thereof include continuous papermaking machines such as a fourdrinier type, a cylinder type, and an inclined type, or a multi-layer combined papermaking machine combining these.

[0025] In addition, in the present embodiment, surface treatment of treating the surface of the paper substrate with a chemical may be performed. Examples of the chemical used for the surface treatment include a sizing agent, a water resistance agent, a water retention agent, a thickening agent, and a lubricant. As the apparatus used in the surface treatment step, a known apparatus can be used.

[0026] <Heat seal layer> The wrapping paper of the present embodiment has a heat seal layer. The heat seal layer is a layer that melts and adheres by heating, ultrasonic waves, etc. The heat seal layer may be provided by coating, dry lamination, or extrusion lamination. Among these, from the viewpoint of obtaining wrapping paper with excellent visibility and paper feeding properties and reduced environmental impact, it is preferable to provide it by coating or by extrusion lamination. The heat seal layer is preferably directly laminated on the paper substrate. By not passing through other layers, it is possible to reduce the basis weight of the entire wrapping paper, and it is preferable because wrapping paper with excellent visibility can be obtained.

[0027] (Coating layer) When provided by coating, the heat seal layer preferably contains a water-dispersible resin binder. A water-dispersible resin binder is a resin binder that is not water-soluble (specifically, the solubility in water at 25°C is 10 g / L or less), but is in a state of being finely dispersed in water like an emulsion or a suspension. In addition, when the water-dispersible resin binder also falls under the following lubricants, it shall be classified as a lubricant.

[0028] The water-dispersible resin binder is not particularly limited as long as it exhibits the effects of the present invention, but examples include polyolefin resins (such as polyethylene and polypropylene), vinyl chloride resins, styrene resins, styrene-butadiene copolymers, styrene-unsaturated carboxylic acid copolymers (for example, styrene-(meth)acrylic acid copolymer), acrylic resins, acrylonitrile-styrene copolymers, acrylonitrile-butadiene copolymers, ABS resins, AAS resins, AES resins, vinylidene chloride resins, polyurethane resins, poly-4-methylpentene-1 resins, polybutene-1 resins, vinylidene fluoride resins, vinyl fluoride resins, fluorine resins, polycarbonate resins, polyamide resins, acetal resins, polyphenylene oxide resins, polyester resins (such as polyethylene terephthalate and polybutylene terephthalate), polyphenylene sulfide resins, polyimide resins, polysulfone resins, polyethersulfone resins, polyarylate resins, olefin-unsaturated carboxylic acid copolymers, and modified products thereof. These may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of styrene-butadiene copolymers and olefin-unsaturated carboxylic acid copolymers is preferable. Furthermore, from the viewpoint of increasing the heat seal peel strength, olefin-unsaturated carboxylic acid copolymers are more preferable, and from the viewpoints of availability, cost, and recyclability, styrene-butadiene copolymers are more preferable.

[0029] Examples of the olefin-unsaturated carboxylic acid copolymer include ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid alkyl ester copolymers, etc. Among them, ethylene-(meth)acrylic acid copolymers are preferable, and ethylene-acrylic acid copolymers are more preferable. Therefore, the water-dispersible resin binder contained in the heat seal layer is preferably at least one selected from the group consisting of styrene-butadiene copolymers and ethylene-(meth)acrylic acid copolymers. Note that the olefin-unsaturated carboxylic acid copolymer may be an ionomer.

[0030] As the styrene-butadiene copolymer, either a synthetic product or a commercially available product may be used. Commercially available products include Nipol latex LX407G51, LX407S10, LX407S12, LX410, LX415M, LX416, LX430, LX433C, 2507H manufactured by Zeon Corporation, Nalster SR-101, SR-102, SR-103, SR-115, SR-153 manufactured by A&R Corporation, styrene butadiene latex 0602, 0597C manufactured by JSR Corporation, etc.

[0031] As the ethylene-(meth)acrylic acid copolymer, either a synthetic product or a commercially available product may be used. Commercially available products include MP498345N, MP4983R, MP4990R, MFHS1279 manufactured by Michaelman Japan Co., Ltd., Zicen (registered trademark) A, Zicen (registered trademark) AC manufactured by Sumitomo Seika Chemical Co., Ltd., Chemparl S series manufactured by Mitsui Chemicals, Inc., etc.

[0032] The glass transition temperature of the water-dispersible resin binder is preferably 0 °C or higher, more preferably 10 °C or higher, and even more preferably 15 °C or higher. By using a water-dispersible resin binder having a glass transition temperature of the above lower limit or higher, the occurrence of blocking can also be suppressed. And from the viewpoint of heat sealability, it is preferably 100 °C or lower, more preferably 80 °C or lower, even more preferably 60 °C or lower, and still more preferably 50 °C or lower. The glass transition temperature of the water-dispersible resin binder shall adopt the value measured by a differential scanning calorimeter.

[0033] The content of the water-dispersible resin binder in the heat-sealing layer is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and still more preferably 80% by mass or more, and is 100% by mass or less, preferably 99% by mass or less, and more preferably 98% by mass or less. Within the above range, heat-sealing paper having high heat-seal peel strength can be obtained.

[0034] That is, according to one embodiment of the present invention, the content of the styrene-butadiene copolymer and the olefin-unsaturated carboxylic acid copolymer (preferably ethylene-(meth)acrylic acid copolymer) in the heat-sealing layer is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and still more preferably 90% by mass or more, and is 100% by mass or less, preferably 99% by mass or less, and more preferably 98% by mass or less.

[0035] - Lubricant - From the viewpoints of imparting slipperiness to the heat-sealing paper and suppressing blocking, the heat-sealing layer may contain a lubricant in addition to the above water-dispersible resin binder. A lubricant is a substance that can reduce the friction coefficient of the surface of the heat-sealing layer by being blended into the heat-sealing layer.

[0036] The lubricant is not particularly limited, and for example, wax, metallic soap, fatty acid ester, etc. can be used. The lubricant may be used alone or in combination of two or more. Examples of the wax include natural waxes such as waxes derived from animals or plants (e.g., beeswax, carnauba wax, etc.), mineral waxes (e.g., microcrystalline wax, etc.), petroleum waxes; synthetic waxes such as polyolefin wax, paraffin wax, polyester wax, etc. Examples of the metallic soap include calcium stearate, sodium stearate, zinc stearate, aluminum stearate, magnesium stearate, sodium fatty acid soap, potassium oleate soap, potassium castor oil soap, and their composites, etc. Among the above lubricants, paraffin wax, carnauba wax, and polyolefin wax are preferred because they have a relatively low melting point and the wax component is easily formed on the surface of the coating layer, and they have an excellent blocking suppression effect. That is, the lubricant is preferably at least one selected from the group consisting of paraffin wax, carnauba wax, and polyolefin wax. From the viewpoints of imparting slipperiness and improving moisture resistance, paraffin wax is preferred. As for carnauba wax, either a synthetic product or a commercially available product can be used. Examples of commercially available products include Cerol 524 manufactured by Chukyo Yushi Co., Ltd., ML160RPH manufactured by Michaelman Co., etc. As for paraffin wax, either a synthetic product or a commercially available product can be used. Examples of commercially available products include Hydrin L-700 manufactured by Chukyo Yushi Co., Ltd., etc. As for polyethylene wax, either a synthetic product or a commercially available product can be used. Examples of commercially available products include Aquacer 531 manufactured by BYK Co., etc.

[0037] When the heat seal layer contains a lubricant, the content of the lubricant is preferably 0.2 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more, still more preferably 1 part by mass or more, and more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less, based on 100 parts by mass of the water-dispersible resin binder.

[0038] When the heat-sealing layer contains a lubricant, the content of the lubricant in the heat-sealing layer is preferably 0.1% by mass or more and 30% by mass or less, more preferably 0.3% by mass or more, still more preferably 1% by mass or more, and more preferably 10% by mass or less, still more preferably 5% by mass or less.

[0039] In the present embodiment, the heat-sealing layer contains a water-dispersible resin binder, and in addition to the water-dispersible resin binder, it preferably contains a lubricant. Further, in addition to the water-dispersible resin binder and, if necessary, the lubricant, a pigment may be contained.

[0040] - Pigment - In the present embodiment, the heat-sealing layer may contain a pigment in addition to the water-dispersible resin binder. By containing a pigment, when manufacturing the heat-sealing paper, the problem that the coated surface of the heat-sealing layer adheres to the back surface of the heat-sealing paper and peels off (blocks) is suppressed, and a heat-sealing paper excellent in blocking resistance can be obtained.

[0041] As the pigment, a pigment having an aspect ratio of 20 or more and 10,000 or less is preferable. When the aspect ratio of the pigment is 20 or more, it is preferable because it is excellent in terms of heat-sealing peel strength and blocking resistance. Also, when it is 10,000 or less, it is preferable because it is easily available and excellent in the smoothness of the surface of the heat-sealing layer. The aspect ratio of the pigment is more preferably 25 or more, still more preferably 30 or more, particularly preferably 60 or more, and more preferably 1,000 or less, still more preferably 300 or less. The aspect ratio of the pigment means the major axis / minor axis and may be measured by the following method.

[0042] The pigment is preferably a layered inorganic compound having an aspect ratio of 20 or more. The form of the layered inorganic compound is plate-like. When the pigment is plate-like, the protrusion of the pigment from the surface of the heat-sealing layer is suppressed, and a heat-sealing layer excellent in blocking resistance can be obtained while maintaining the heat-sealing property.

[0043] The pigment preferably has a length (average particle diameter) of 0.1 μm or more and 100 μm or less. When the length is 0.1 μm or more, the pigment is likely to be arranged parallel to the paper substrate. Further, when the length is 100 μm or less, there is less concern that a part of the pigment protrudes from the heat seal layer. The length of the pigment is more preferably 0.3 μm or more, still more preferably 0.5 μm or more, particularly preferably 1.0 μm or more, and is more preferably 30 μm or less, still more preferably 20 μm or less, particularly preferably 15 μm or less.

[0044] Here, the length of the pigment in the state of being contained in the heat seal layer is determined as follows. For the cross section of the heat seal layer, a magnified photograph is taken using an electron microscope. At this time, the magnification is set such that about 20 to 30 pigments are included in the screen. The individual lengths of the pigments in the screen are measured. Then, the average value of the obtained lengths is calculated and taken as the length of the pigment. Note that the length of the pigment may also be described in terms of particle diameter.

[0045] The pigment preferably has a thickness of 5 nm or more and 200 nm or less. The thickness of the pigment is more preferably 100 nm or less, still more preferably 80 nm or less, even more preferably 50 nm or less, particularly preferably 30 nm or less. Also, it is more preferably 10 nm or more. A smaller average thickness of the pigment results in a higher heat seal peel strength. Here, the thickness of the pigment in the state of being contained in the heat seal layer is determined as follows. For the cross section of the heat seal layer, a magnified photograph is taken using an electron microscope. At this time, the magnification is set such that about 20 to 30 pigments are included in the screen. The individual thicknesses of the pigments in the screen are measured. Then, the average value of the obtained thicknesses is calculated and taken as the thickness of the pigment.

[0046] Specific examples of the pigment include mica, bentonite, kaolin, pyrophyllite, talc, smectite, vermiculite, chlorite, septarian chlorite, serpentine, stilpnomelane, montmorillonite, heavy calcium carbonate (ground calcium carbonate), light calcium carbonate (synthetic calcium carbonate), composite synthetic pigments of calcium carbonate and other hydrophilic organic compounds, satin white, lithopone, titanium dioxide, silica, barium sulfate, calcium sulfate, alumina, aluminum hydroxide, zinc oxide, magnesium carbonate, silicate, colloidal silica, plastic pigments of organic pigments that are hollow or dense, binder pigments, plastic beads, microcapsules, and the like.

[0047] Specific examples of mica include synthetic mica (for example, swelling synthetic mica), muscovite (mascovite), sericite (sericite), phlogopite (fluorophlogopite), biotite (biotite), fluorophlogopite (synthetic mica), red mica, soda mica, vanadium mica, illite, tin mica, paragonite, brittle mica, and the like. Specific examples of bentonite include montmorillonite.

[0048] Specific examples of kaolin include various kaolins such as kaolin, calcined kaolin, structured kaolin, and delaminated kaolin.

[0049] Among these, particularly from the viewpoints of heat seal peel strength, blocking resistance, and economy, pigments having an aspect ratio of 20 or more are preferred, and it is more preferable to contain any one or more of mica, bentonite, kaolin, and talc, and kaolin is even more preferable.

[0050] When the heat-sealing layer contains a pigment, from the viewpoints of blocking resistance and recyclability, the content of the pigment is preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, and even more preferably 8 parts by mass or more with respect to 100 parts by mass of the water-dispersible resin binder. On the other hand, from the viewpoint of heat-sealing property, it is preferably 200 parts by mass or less, more preferably 100 parts by mass or less, and still more preferably 30 parts by mass or less.

[0051] When the heat-sealing layer contains a pigment, from the viewpoints of blocking resistance and recyclability, the content of the pigment in the heat-sealing layer is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, and even more preferably 8% by mass or more, and from the viewpoint of heat-sealing property, it is preferably 70% by mass or less, more preferably 30% by mass or less, and still more preferably 20% by mass or less.

[0052] -Other components- The heat-sealing layer may contain other components in addition to the above water-dispersible resin binder, lubricant and / or pigment as required. Examples of other components include, for example, silane coupling agents; defoaming agents; viscosity modifiers; leveling agents such as surfactants and alcohols; colorants such as coloring dyes.

[0053] The method of coating the heat-sealing layer on the paper substrate is not particularly limited, and known coating equipment may be used. Examples of coating equipment include, for example, blade coaters, bar coaters, air knife coaters, slit die coaters, gravure coaters, microgravure coaters, roll coaters, size presses, gate roll coaters, simsizers, etc.

[0054] After coating, it is preferable to dry the coating liquid, and the drying equipment for drying is not particularly limited, and known equipment can be used. Examples of drying equipment include, for example, hot air dryers, infrared dryers, gas burners, hot plates, etc. Also, the drying temperature may be appropriately set in consideration of the drying time and the like. Also, after drying the coating liquid, supercalendering treatment may be performed. Supercalendering treatment is installed independently of papermaking. Generally, paper or the like to be treated is passed between metal rolls or between a metal roll and an elastic roll, and heating, pressurization, etc. are performed. The supercalendering treatment may be performed in one stage or in multiple stages, and is not particularly limited.

[0055] The solvent of the heat-seal layer coating liquid is not particularly limited, and water or organic solvents such as ethanol, isopropyl alcohol, methyl ethyl ketone, and toluene can be used. Among these, from the viewpoint of not causing problems with volatile organic solvents, water is preferable as the dispersion medium of the heat-seal layer coating liquid. That is, the heat-seal layer coating liquid is preferably an aqueous composition for the heat-seal layer.

[0056] The solid content (solid concentration) of the heat-seal layer coating liquid is not particularly limited and may be appropriately selected from the viewpoints of coatability and ease of drying. Preferably, it is 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and preferably 80% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less, and even more preferably 40% by mass or less.

[0057] (Laminated layer) When the heat-seal layer is provided by lamination, it may be appropriately selected and manufactured from conventionally known manufacturing methods. For example, it may be appropriately selected from among the dry lamination method, the melt extrusion method, the melt casting method, the calendar method, etc. Among these, laminating with a paper substrate without an adhesive layer is preferable from the viewpoint of reducing the environmental load, and the melt extrusion method and the melt casting method are preferable, and the melt extrusion method is more preferable.

[0058] As the resin constituting the heat-sealing layer, any thermoplastic resin, either crystalline or amorphous, can be used according to the application. Examples of thermoplastic resins include polyolefin resins such as polyethylene (low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), etc.), polypropylene, and polymethylpentene; polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyamide resins; polylactic acid (PLA); polyhydroxybutyric acid (PHB); polybutylene succinate (PBS); poly(butylene adipate-co-butylene terephthalate) (PBAT); polycaprolactone (PCL); biodegradable resins such as poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH); polystyrene; polyvinyl chloride; acrylonitrile-butadiene-styrene (ABS) resin; acrylic resin; and modified polyphenylene ether (PPE). Among these, as thermoplastic resins, it is preferable to use polyolefin resins such as polyethylene (LDPE, MDPE, HDPE, LLDPE, etc.), polypropylene, and polymethylpentene, and polylactic acid (PLA), and it is more preferable to use polyethylene and polypropylene. These thermoplastic resins may be used alone or in combination of two or more.

[0059] The heat-sealing layer may be formed as a single layer of a single resin, or as a single layer formed by mixing a plurality of resins, or as these multi-layers (for example, single resin layer / single resin layer, single resin layer / mixed resin layer, mixed resin layer / mixed resin layer).

[0060] (Grammage) The grammage of the heat-sealing layer may be appropriately selected within the range where the content of the paper base material in the wrapping paper is 50% by mass or more, and is not particularly limited. However, from the viewpoint of obtaining wrapping paper with excellent visibility, it is preferable that the grammage is small. When the heat-sealing layer is provided by coating, the grammage of the heat-sealing layer is preferably 1 g / m from the viewpoints of reducing environmental load, heat-sealing property, and visibility. 220 g / m or less, more preferably 2 g / m or more, and even more preferably 10 g / m or less, still more preferably 5 g / m or less, and most preferably 3 g / m or less. 2 or less, more preferably 2 g / m or more, 2 and even more preferably 10 g / m or less, 2 still more preferably 5 g / m or less, 2 and most preferably 3 g / m or less. 2 It is less than.

[0061] When the heat seal layer is provided by lamination, the basis weight of the heat seal layer is preferably 5 g / m or more and 40 g / m or less, more preferably 10 g / m or more, still more preferably 15 g / m or more, and even more preferably 30 g / m or less, still more preferably 25 g / m or less, and most preferably 20 g / m or less, and even more preferably 19 g / m or less, from the viewpoints of reducing environmental load, heat sealability, and visibility. 2 or more and 40 g / m 2 or less, more preferably 10 g / m or more, 2 still more preferably 15 g / m or more, 2 and even more preferably 30 g / m or less, 2 still more preferably 25 g / m or less, 2 and most preferably 20 g / m or less, and even more preferably 19 g / m or less. 2 It is less than, and even more preferably 19 g / m or less. 2 It is less than. When the heat seal layer is provided by lamination, the thickness of the heat seal layer is preferably 5 μm or more and 40 μm or less, more preferably 9 μm or more, still more preferably 12 μm or more, and even more preferably 30 μm or less, still more preferably 25 μm or less, and most preferably 20 μm or less, and even more preferably 19 μm or less, from the same viewpoints.

[0062] <Properties of the wrapping paper> (Content of the paper base material) In the wrapping paper of this example, from the viewpoint of reducing environmental load, the content of the paper base material in the wrapping paper is 50% by mass or more. The content of the paper base material is preferably 55% by mass or more, more preferably 60% by mass or more. The upper limit is not particularly limited, but from the viewpoint of heat sealability, it is preferably 98% by mass or less, more preferably 96% by mass or less, and still more preferably 94% by mass or less.

[0063] (Basis weight) The basis weight of the wrapping paper of this embodiment is preferably 20 g / m 2 or more and 85 g / m 2 or less, more preferably 25 g / m 2 or more, even more preferably 30 g / m 2 or more, and more preferably 75 g / m 2 or less, even more preferably 60 g / m 2 or less, even more preferably 55 g / m 2 or less, still more preferably 50 g / m 2 or less. The basis weight of the wrapping paper can be adjusted to a desired range by appropriately adjusting the basis weights of the paper base material and the heat seal layer. The basis weight of the wrapping paper is measured by the method described in the examples.

[0064] (Thickness) The thickness of the wrapping paper of this embodiment is preferably 20 μm or more and 100 μm or less, more preferably 25 μm or more, even more preferably 30 μm or more, even more preferably 34 μm or more, still more preferably 38 μm or more, and more preferably 90 μm or less, even more preferably 70 μm or less, even more preferably 65 μm or less. When the thickness of the wrapping paper is within the above range, a desired tensile strength can be obtained, and a wrapping paper with excellent visibility and excellent paper feeding property can be obtained, which is preferable. The thickness of the wrapping paper can be adjusted to a desired range by appropriately adjusting the thicknesses of the paper base material and the heat seal layer. The thickness of the wrapping paper is measured by the method described in the examples.

[0065] (Density) The density of the wrapping paper of this embodiment is preferably 0.5 g / cm 3 or more and 1.0 g / cm 3 or less, more preferably 0.65 g / cm 3 or more, even more preferably 0.70 g / cm 3 or more, and more preferably 0.95 g / cm 3 or less, even more preferably 0.90 g / cm 3More preferably, it is 0.85 g / cm or less hereinafter. 3 It is as follows. When the density of the wrapping paper is within the above range, a wrapping paper with a desired tensile strength, excellent visibility, and excellent paper feeding property can be obtained, which is preferable. The density of the wrapping paper can be adjusted to a desired range by appropriately adjusting the density of the paper base material and the type of resin used for the heat seal layer. The density of the wrapping paper is measured by the method described in the examples.

[0066] (Opacity) From the viewpoint of visibility, the opacity of the wrapping paper of this embodiment is 80% or less. The opacity of the wrapping paper is preferably 15% or more and 70% or less, more preferably 60% or less, still more preferably 55% or less, and more preferably 25% or more, still more preferably 35% or more. When the opacity of the wrapping paper is within the above range, it is preferable because it is excellent in visibility and ease of manufacture. The opacity of the wrapping paper can be adjusted to a desired range by appropriately adjusting the basis weight and thickness of the paper base material and the heat seal layer. The opacity of the wrapping paper is measured by the method described in the examples.

[0067] (Tensile strength) The wrapping paper of this embodiment has a longitudinal tensile strength of 1.2 kN / m or more. When the longitudinal tensile strength is 1.2 kN / m or more, the wrapping paper of this embodiment is excellent in paper feeding property, and tearing of the wrapping paper during paper feeding is suppressed. The longitudinal tear strength is preferably 1.3 kN / m or more and 10.0 kN / m or less, and from the viewpoint of ease of manufacture, more preferably 8.0 kN / m or less, still more preferably 6.5 kN / m or less, and even more preferably 5.0 kN / m or less.

[0068] The transverse tensile strength is preferably 1.1 kN / m or more and 9.0 kN / m or less, more preferably 1.2 kN / m or more, from the viewpoint of paper feeding performance, and from the viewpoint of ease of manufacture, more preferably 7.0 kN / m or less, still more preferably 5.5 kN / m or less, and even more preferably 4.0 kN / m or less. The tensile strength is measured in accordance with JIS P 8116:2000. The tensile strength is adjusted by appropriately selecting the beating degree of the raw material pulp, the basis weight, thickness, density of the paper substrate, the papermaking conditions of the paper substrate, the type and thickness of the heat seal layer, etc. When the beating degree of the raw material pulp is increased, the tensile strength tends to increase. Also, when the basis weight, thickness, density of the paper substrate, and the thickness of the heat seal layer are large, the tensile strength tends to increase.

[0069] 〔Package〕 The package of this embodiment is a package produced using the wrapping paper of this embodiment, and preferably consists only of the wrapping paper of this embodiment. The package of this embodiment may be a package produced by any method. For example, it may be used for a three-side seal packaging bag, a four-side seal packaging bag, a pillow packaging bag, etc., but it preferably has a lid material and a bottom material having a recess, and is used for a package that can accommodate and seal the object to be accommodated in the recess by heat-sealing the lid material and the bottom material. FIG. 1 shows an example of a suitable package in this embodiment. FIG. 1 shows a schematic cross-sectional view in the manufacture of the package. It is preferable that the package 10 is obtained by placing the wrapping paper 2 serving as the bottom material on the mold 1 in which the recess is formed, making it follow the shape of the recess, placing the object to be accommodated 4 on the wrapping paper 2 serving as the bottom material, then placing the wrapping paper 3 serving as the lid material, and heat-sealing the wrapping paper 2 serving as the bottom material and the wrapping paper 3 serving as the lid material. In FIG. 1, the arrow means the longitudinal direction of the wrapping paper. When forming the package shown in FIG. 1, the longitudinal direction of the wrapping paper must have a followability that follows the recess of the base material, and for use in this application, the followability is particularly important. Also, the object to be accommodated 4 preferably has a rod-like shape. Thus, the wrapping paper of this embodiment is preferably used for a package when the object to be contained is a rod-shaped substance.

Examples

[0070] The features of the present invention will be described more specifically below by giving examples and comparative examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. Note that "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

[0071] [Evaluation and Analysis] The following evaluations and analyses were performed on the raw material pulp, wrapping paper, and package of the examples and comparative examples.

[0072] [Raw Material Pulp] [Measurement of Canadian Standard Freeness (CSF)] The Canadian Standard Freeness (CSF) of the raw material pulp was measured in accordance with JIS P 8121-2:2012.

[0073] [Paper Substrate and Wrapping Paper] [Grammage] The grammage of the paper substrate and the wrapping paper was measured in accordance with JIS P 8124:2011. The grammage of the heat-sealing layer was calculated from the values of the paper substrate and the wrapping paper.

[0074] [Thickness] The thickness of the paper substrate and the wrapping paper was measured in accordance with JIS P 8118:2014 at the thickness when a pressure of 100 kPa ± 10 kPa was applied to the circular region (200 mm 2 ) of the test piece. Note that the thickness of the heat-sealing layer was calculated from the values of the paper substrate and the wrapping paper.

[0075] [Density] The density of the paper substrate and the wrapping paper was measured in accordance with JIS P 8118:2014. Note that the density of the heat-sealing layer was calculated from the numerical values of the paper base material and the wrapping paper.

[0076] <Opacity> The opacity of the wrapping paper was measured in accordance with JIS P 8149:2000.

[0077] <Visibility> Using the wrapping paper obtained in each example, the object to be packaged (Pilot Corporation's friction ball 3 slim) was packaged by four-side sealing to obtain a package. The ease of confirming the presence or absence of the object to be packaged was evaluated from the outside of the obtained package. The test was conducted with 10 people, and the total score (for 10 people) was obtained and evaluated in the following three levels ("A" to "C"). 4: The color and shape of the object to be packaged can be discriminated. 3: The shape of the object to be packaged can be grasped. 2: The presence or absence of the object to be packaged can be confirmed. 1: The presence or absence of the object to be packaged cannot be confirmed. A: The total score is 30 points or more. B: The total score is 20 points or more and less than 30 points. C: The total score is less than 20 points.

[0078] <Paper feeding property> Test specimens obtained by winding the wrapping paper obtained in each example into a roll (paper width 300 mm, weight 10 kg) were prepared in two for each example. One test specimen was placed on a free roller conveyor, the end of the wrapping paper was gripped by a machine (Lami-Man IKO-650EM manufactured by Yuubon Co., Ltd.), and the presence or absence of tearing was observed when pulled at a speed of 2.5 m / min. Similarly, the presence or absence of tearing was observed when the other test specimen was pulled at a speed of 3.0 m / min, and evaluated in the following three levels. A: No tearing occurs at either speed. B: No tearing occurs at 2.5 m / min, but tearing occurs at 3.0 m / min. C: Tearing occurs at both speeds.

[0079] <Heat-sealing property> The wrapping paper obtained in each example was cut into a size of 10 cm × 10 cm, and two pieces of each were overlapped so that the heat-sealing layers were in contact with each other, and a heat-sealing tester (manufactured by Tester Sangyo Co., Ltd., TP-701-B) was used under certain conditions (temperature: 130 °C, pressure: 1.0 kgf / cm 2 , time: 0.5 seconds, adhesion width: 1 cm) to heat-seal the four sides. One tester pulled and peeled by hand from the edge of the heat-sealed substrate for 5 samples for each example, and evaluated them in three stages based on the state after peeling. A: Paper layer peeling exists on almost the entire surface (80% or more of the area) B: Paper layer peeling exists in part (20% or more and less than 80% of the area) C: Almost no paper layer peeling (less than 20% of the area)

[0080] [Example 1] (Production of paper substrate) Hardwood bleached kraft pulp (LBKP) was beaten to CSF 400 mL, and then a pulp slurry with a concentration of 3.8% by mass was obtained. To this pulp slurry, 0.9 parts by mass of an anionic dry paper strength enhancer mainly composed of polyacrylamide (trade name: PS-NH20B, manufactured by Arakawa Chemical Industries, Ltd.), 0.9 parts by mass of a cationic wet paper strength enhancer mainly composed of polyamide polyamine epichlorohydrin (trade name: WS4024, manufactured by Starlight PMC Co., Ltd.), and 0.3 parts by mass of an alkyl ketene dimer (trade name: AD1612, manufactured by Starlight PMC Co., Ltd.) as a neutral sizing agent were mixed based on 100 parts by mass of pulp solids, and stirred to obtain a papermaking stock. This papermaking stock was adjusted to a concentration of 0.5% by mass and was made into paper using an inclined wire paper machine to obtain a paper substrate with a basis weight of 18 g / m 2 .

[0081] (Formation of heat-sealing layer) LDPE (manufactured by Nippon Polyethylene Co., Ltd., LC522) was laminated as a heat-sealing layer on one surface of the obtained paper substrate. The lamination of the heat-sealing layer on one side of the paper substrate was carried out by the melt extrusion method under the conditions of a lamination temperature of 330 °C and a lamination speed of 120 m / min. A wrapping paper with a basis weight of the heat-sealing layer of 17 g / m 2 was obtained.

[0082] [Example 2] A paper base material was made into paper by an inclined wire paper machine, and wrapping paper was obtained under the same conditions as in Example 1 except that the basis weight was 30 g / m 2 .

[0083] [Example 3] A paper base material was made into paper by an inclined wire paper machine, and wrapping paper was obtained under the same conditions as in Example 1 except that the basis weight was 30 g / m 2 and the heat seal layer was formed by the following method. (Formation of heat seal layer) On one surface of the obtained paper base material, the heat seal layer coating amount after drying was 2.5 g / m 2 , and the following heat seal layer coating material was applied with a gravure coater (using a smoothing bar) to form a heat seal layer. -Preparation of heat seal layer coating material- 98 parts (in terms of solid content) of an aqueous dispersion of a styrene / butadiene copolymer (manufactured by Nippon Zeon Co., Ltd., Nipol latex LX407S12, solid content concentration 46% by mass, glass transition temperature 18 °C (catalog value)) and 2 parts (in terms of solid content) of a paraffin wax emulsion (manufactured by Chukyo Yushi Co., Ltd., Hydrin L-700, solid content concentration 30% by mass) were mixed, water was added and stirred so that the solid content concentration became 33% by mass, and a heat seal layer coating material (solid content concentration 33% by mass) was prepared. The above styrene / butadiene copolymer had a solubility in water at 25 °C of 10 g / L or less.

[0084] [Example 4] A paper base material was made into paper by an inclined wire paper machine, and a packaging base material was obtained under the same conditions as in Example 1 except that the basis weight was 50 g / m 2 .

[0085] [Comparative Example 1] A paper base material was made into paper by an inclined wire paper machine, and wrapping paper was obtained under the same conditions as in Example 1 except that the basis weight was 70 g / m 2 .

[0086] [Comparative Example 2] A packaging paper was obtained under the same conditions as in Example 1, except that it was made on an inclined wire paper machine using a paper base material with a basis weight of 15 g / m 2 The evaluation described above was performed on the obtained packaging paper.

[0087] The obtained packaging paper was evaluated as described above. The results are shown in the following table.

[0088]

Table 1

[0089] From the results of the examples and comparative examples, the package obtained using the packaging paper of the present embodiment was excellent in visibility. Furthermore, the packaging paper of the present embodiment had excellent feedability and heat sealability. On the other hand, the package obtained using the packaging paper of Comparative Example 1, where the basis weight of the paper base material exceeded 60 g / m 2 and the opacity of the packaging paper exceeded 80%, was inferior in visibility, and the packaging paper was inferior in heat sealability. Also, the packaging paper of Comparative Example 2, where the tensile strength in the longitudinal direction was less than 1.2 kN / m, was inferior in feedability.

Industrial Applicability

[0090] The packaging paper of the present invention is suitable as a flexible packaging material, excellent in visibility, excellent in feedability, and further excellent in heat sealability, and is suitably used for forming a package.

Explanation of Reference Numerals

[0091] 1 Mold 2 Packaging paper as a base material 3 Packaging paper as a lid material 4 Contained object 10 Package

Claims

1. A wrapping paper having a heat seal layer on a paper base material, The paper base material has a basis weight of 60 g / m ２ is as follows: The content of the paper base material in the wrapping paper is 50% by mass or more, The opacity of the wrapping paper is 80% or less; The wrapping paper has a longitudinal tensile strength of 1.2 kN / m or more. wrapping paper.

2. The wrapping paper of claim 1 having a thickness of 90 μm or less.

3. Basis weight 75g / m ２ The wrapping paper according to claim 1 or 2, wherein:

4. 3. The wrapping paper according to claim 1, wherein the raw pulp of the paper base material contains hardwood bleached kraft pulp, and the content of hardwood bleached kraft pulp in the raw pulp is 85 mass% or more.

5. 3. The wrapping paper according to claim 1, wherein the paper base material and the heat seal layer are directly laminated together.

6. The heat seal layer has a basis weight of 20 g / m ２ or a laminate layer having a basis weight of 3 g / m ２ The wrapping paper according to claim 1 or 2, wherein the coating layer is less than 100 μm.

7. A cover material and a base material having a recess, A package capable of housing an object to be housed in the recess and sealing the recess by heat sealing the lid material and the base material, The lid material and the base material are made of the wrapping paper according to claim 1 or 2. packaging.

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