WO2021095402A1

WO2021095402A1 - Food-packaging sheet

Info

Publication number: WO2021095402A1
Application number: PCT/JP2020/037913
Authority: WO
Inventors: 松本　真一郎
Original assignee: 三菱製紙株式会社
Priority date: 2019-11-13
Filing date: 2020-10-06
Publication date: 2021-05-20
Also published as: JP7377176B2; JP2021075833A; KR20220056237A

Abstract

The present invention addresses the problem of providing a food-packaging sheet that has water resistance, oil resistance, and gas barrier properties, and in which the occurrence of pin holes can be reduced. Said problem can be addressed by this food packaging sheet having a sheet-supporting body, and at least one coating layer on one surface of the sheet-supporting body. The at least one coating layer contains a polyvinylidene chloride-based polymer having, as a main component, a vinylidene chloride monomer as a constituent unit of resin.

Description

Food wrapping paper

The present invention relates to a food packaging material such as a food packaging, a bag for containing food, or a container for containing food, and the support is paper.

Most of the food packaging materials such as food packaging, food bags or food containers have a laminated structure of plastic films or a film having a metal vapor deposition film. On the other hand, due to the environmental problems of plastic products, there is a food packaging material made of a paper support having a gas barrier property against water vapor and oxygen from the outside in order to suppress deterioration of the food. For example, as a paper barrier packaging material having both excellent gas barrier properties and water vapor barrier properties, which has a water vapor barrier layer and a gas barrier layer provided by coating a water-based paint, a pigment and a water vapor barrier resin are contained on a paper base material. A paper barrier packaging material in which a water vapor barrier layer and a gas barrier layer containing a water-soluble polymer are provided in this order and the water vapor barrier resin is an acrylic synthetic resin is known (see, for example, Patent Document 1). Further, an adhesive layer and an adhesive layer are provided on a base material such as various plastic materials, various vapor-deposited films and paper that can be used for packaging foods and the like, and the adhesive layer is an ethylene unsaturated carboxylic acid copolymer. A laminate is known which is formed by drying a dispersion of composite particles containing an acrylic polymer and the adhesive layer is made of polyvinyl chloride and / or polyvinylidene chloride (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2013-176950 International Publication No. 2016/076130 Pamphlet

Food packaging paper such as food packaging, food bags or food containers must be water and oil resistant to water and oil derived from food. In addition, food packaging paper must have a gas barrier property that prevents the permeation of water vapor, moisture or oxygen and protects food from deterioration. In addition, depending on the form of packaging, it is necessary to put food in it before sealing it, and the food packaging paper needs to be suitable for heat sealing. Further, in recent years, due to the trend of the public claiming harm related to fragrance, the food packaging paper to be sealed needs to have a flavor barrier property to reduce leakage of fragrance generated from food.

Furthermore, in food packaging paper, which is a paper support, pinholes occur in the coating layer provided on the paper support due to the characteristics of the paper such as absorbency. When a coating layer containing a water and oil resistant agent or a gas barrier agent is provided on the paper support, sufficient water resistance, oil resistance, and gas barrier properties cannot be obtained due to the presence of pinholes. The produced food packaging paper must use the part where there is no pinhole, and as a result, the yield is reduced.

A first object of the present invention is to provide a food packaging paper having a gas barrier property and capable of reducing the occurrence of pinholes. A second object of the present invention is to provide a food packaging paper which has water resistance, oil resistance, gas barrier property, flavor barrier property, can reduce the occurrence of pinholes, and has heat seal suitability. Is.

As a result of diligent studies by the present inventor, the object of the present invention is achieved by the following.

[1] A paper support and at least one coating layer on one side of the paper support are provided.
A food packaging paper in which at least one of the coating layers contains a polyvinylidene chloride-based polymer containing a vinylidene chloride monomer as a main component as a constituent unit of a resin.

[2] The food packaging paper according to the above [1], wherein the coating layer is one layer.

[3] The coating layer includes a first coating layer and a second coating layer outside the first coating layer with the paper support as a reference.
The first coating layer contains a polyvinylidene chloride-based polymer containing a vinylidene chloride monomer as a main component as a constituent unit of the resin.
The food packaging paper according to the above [1], wherein the second coating layer contains an acrylic resin.

[4] The paper support has a first coating layer on one side of the paper support, and a second coating layer on the outside of the first coating layer with the paper support as a reference.
The first coating layer contains a polyvinylidene chloride-based polymer containing a vinylidene chloride monomer as a main component as a constituent unit of the resin.
A food packaging paper in which the second coating layer contains an acrylic resin.

[5] The food packaging paper according to the above [4], wherein the content of the vinylidene chloride monomer in the polymer is 85% by mass or more and 95% by mass or less in the polyvinylidene chloride-based polymer.

[6] A polyvinylidene chloride-based weight having an undercoat layer between the paper support and the first coating layer, and the undercoat layer having a vinylidene chloride monomer as a main component as a constituent unit of the resin. The food packaging paper according to the above [4] or the above [5], which contains the coalescence and kaolin.

[7] The food packaging according to any one of [4] to [6] above, wherein the garley air permeability of the paper support is 30 seconds or more and 200 seconds or less, which is measured according to ISO5636-5: 2013. Paper.

[8] The polyvinylidene chloride-based polymer is a copolymer containing a vinylidene chloride monomer, a (meth) acrylonitrile-based monomer, and an alkyl (meth) acrylate monomer having 1 to 4 carbon atoms in an alkyl group. The food wrapping paper according to any one of the above [4] to [7].

[9] The food according to any one of [1] to [3] above, wherein the content of the vinylidene chloride monomer in the polymer is 85% by mass or more and 95% by mass or less in the polyvinylidene chloride-based polymer. Wrapping paper.

[10] A polyvinylidene chloride-based polymer having an undercoat layer between the paper support and the coating layer, and the undercoat layer having a vinylidene chloride monomer as a main component as a constituent unit of the resin. , The food packaging paper according to any one of the above [1] to [3] and the above [9], which contains kaolin.

[11] The Garley air permeability of the paper support measured according to ISO 5636-5: 2013 is 30 seconds or more and 200 seconds or less, the above [1] to [3], the above [9] and the above [ 10] The food packaging paper according to any one of.

[12] The polyvinylidene chloride-based polymer is a copolymer containing a vinylidene chloride monomer, a (meth) acrylonitrile-based monomer, and an alkyl (meth) acrylate monomer having 1 to 4 carbon atoms in an alkyl group. The food wrapping paper according to any one of the above [1] to [3] and the above [9] to [11].

According to the above [1] and [2] and the embodiment of the present invention dependent on these (excluding the above [3]), a food packaging paper having a gas barrier property and capable of reducing the occurrence of pinholes is provided. be able to. This makes it possible to achieve the first purpose.
According to the above [3] and [4] and the embodiments of the present invention that are dependent on these, the water resistance, the oil resistance, the gas barrier property, the flavor barrier property, the occurrence of pinholes can be reduced, and the heat can be further reduced. It is to provide a food packaging paper having sealability. As a result, the second purpose can be achieved.

The food packaging paper has a paper support and at least one coating layer on one side of the paper support, and at least one of the coating layers contains vinylidene chloride monomer as a constituent unit of the resin. Contains a polyvinylidene chloride-based polymer having as a main component. In some embodiments, the food packaging paper has one or two coating layers. In some embodiments, the food packaging paper may have an undercoat layer, which will be described later, between the paper support and the coating layer. The reason for this is that the barrier property can be improved, the adhesiveness of the coating layer can be improved, and the occurrence of pinholes can be further reduced.

As an embodiment of the food packaging paper, the surface of the food packaging paper facing the food is the surface of the food packaging paper having the coating layer. Further, the food wrapping paper has the dimensional stability of the paper on the opposite side of the paper support to the side having the coating layer for the purpose of improving the printability on the offset printing machine and / or the digital printing machine. A coating layer or backcoat layer for printing may be provided for the purpose of improvement. Further, the coating layer described above, the undercoating layer described later, or the first coating layer and / or the second coating layer described later can be provided between the coating layer for printing and the paper support. The coating layer or backcoat layer for printing is conventionally known in the field of coated paper for printing.

The paper support is a paper material obtained by adding various additives such as a filler, a sizing agent, a binder, a fixing agent, a retention agent, and a paper strengthening agent to a slurry composed of wood pulp and / or non-wood pulp as necessary. , A base paper made by a conventionally known papermaking method under acidic, neutral or alkaline conditions, a high-quality paper obtained by size-pressing the base paper with a size press solution, a high-quality paper obtained by surface-treating the base paper with a surface treatment solution, or It is a high-quality paper obtained by subjecting the base paper or the high-quality paper to a calendar treatment.
Further, in the paper material, as other additives, a pigment dispersant, a bulking agent, a thickener, a fluidity improver, a pitch control agent, a defoaming agent, a defoaming agent, a mold release agent, a foaming agent, and a penetration agent. One or more selected from agents, moisturizers, preservatives, antifoaming agents, water resistant agents, wet paper strength enhancers, dry paper strength enhancers, etc., as long as the desired effects of the present invention are not impaired. It can be added as appropriate.

Calender processing is a processing that averages the smoothness and thickness by passing paper between rolls. Examples of the calendar processing device include a machine calendar, a soft nip calendar, a super calendar, a multi-stage calendar, and a multi-nip calendar.

Wood pulp is conventionally known in the field of papermaking. Wood pulp is, for example, chemical pulp such as LBKP (Leaf Bleached Kraft Pulp) and NBKP (Needle Bleached Kraft Pulp), GP (Groundwood Pulp), PGW (Pressure GroundWood pulp), RMP (Refiner Mechanical Pulp), TMP (ThermoMechanical Pulp). ), CTMP (ChemiThermoMechanical Pulp), CMP (ChemiMechanical Pulp), CGP (ChemiGroundwood Pulp) and other mechanical pulps, and DIP (DeInked Pulp) and other used paper pulps.
Non-wood pulp is a pulp made of non-wood fibers conventionally known in the field of papermaking. Raw materials for non-wood fibers include, for example, woody basts such as mulberry, honey and ganpi, herbaceous basts such as flax, cannabis and kenaf, leaf fibers such as Manila hemp, abaca and sisal, rice straw, wheat straw and sugar cane. Examples thereof include grasses such as Bacas, bamboo and Espart, and seed hairs such as cotton and linter.
Wood pulp and / or non-wood pulp is one or more selected from the group consisting of said wood pulp and said non-wood pulp.

The filler is a pigment conventionally known in the paper manufacturing field. Pigments include, for example, light calcium carbonate, heavy calcium carbonate, various kaolin, talc, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, silica, aluminum silicate, diatomaceous earth, active white clay, alumina, alumina. Examples thereof include inorganic pigments such as hydrate, aluminum hydroxide, lithopone, zeolite, magnesium carbonate, and magnesium hydroxide. Further, organic pigments such as styrene-based plastic pigments, acrylic-based plastic pigments, polyethylene-based plastic pigments, urea resins, melamine resins and microcapsules can be mentioned. The filler is one or more selected from the group consisting of the inorganic pigment and the organic pigment.

In some embodiments, the ash content of the paper support is 10% by mass or less. In at least one embodiment, the ash content of the paper support is 4% by mass or more and 10% by mass or less. When the ash content is in the above range, the occurrence of pinholes can be satisfactorily reduced. The ash content of the paper can be adjusted by the amount of filler contained in the paper. The ash content of the paper is a value obtained in accordance with ISO1762: 2001 "Paper, board and pools-Determination of resume (ash) on ignition at 525 degree C".

The sizing agent is an internal sizing agent conventionally known in the field of paper manufacturing. Examples of the internal sizing agent include rosin-based sizing agents for acid-free paper, alkenyl anhydride succinic acid, alkylketen dimer, neutral rosin-based sizing agents, and cationic styrene-acrylic sizing agents for neutral paper. Can be mentioned.
Further, the surface sizing agent used for the size press liquid is conventionally known in the paper manufacturing field. Examples of the surface sizing agent include starch-based sizing agents, cellulose-based sizing agents, polyvinyl alcohol-based sizing agents, styrene-acrylic sizing agents, olefin-based sizing agents, styrene-maleic acid-based sizing agents, and acrylamide-based sizing agents. Can be mentioned.

The size press can be performed with a size press device conventionally known in the papermaking field. The size press equipment includes, for example, an inclined size press, a horizontal size press, a rod metering size press, a roll metering size press, and a blade metering size press as a film transfer method, and a simsizer, an optimizer as a rod metering size press. Examples of the speed sizer as a roll metering size press include a gate roll coater, a bill blade coater, a twin blade coater, a velva paper coater, a tab size press, and a calendar size press.

In some embodiments, the garley permeability of the paper support is 30 seconds or more, as measured according to ISO 5636-5: 2013 "Paper and board-Determination of air measurement (medium range) -Part 5: Gurley measurement". It is less than 200 seconds. When the garley air permeability of the paper support is in the above range, the pin is due to the synergistic effect of the paper support and the coating layer, or, when having the undercoat layer, the synergistic effect of the paper support, the undercoat layer and the coating layer. The occurrence of holes can be further reduced.

Garley air permeability is determined by the time it takes for a certain volume of air to pass through a piece of paper. Prepare an inner cylinder covered with a piece of paper. The inner cylinder is floated on an outer cylinder containing a liquid such as oil. Air is compressed by the weight of the inner cylinder in the vertical direction, and this air passes through a piece of paper and the inner cylinder gradually descends in the outer cylinder. Measure the time (seconds) required for a constant volume of air to permeate. The smaller the value, the greater the air permeability of the paper. The Garley air permeability is a value measured using, for example, a B-type Garley densometer manufactured by Toyo Seiki Seisakusho Co., Ltd.
The garley air permeability of the paper support can be measured from the paper support, for example, when the paper support is obtained as described above.
The Garley air permeability of the paper support can be measured, for example, from the exposed paper support by slicing and removing the coating layer and the undercoat layer while observing the cross section of the paper.

Generally, a paper support having low air permeability is considered to be more effective from the viewpoint of gas barrier property. However, from the results examined by the present inventor, a paper support having too little air permeability is not effective for pinholes. The reason for this is presumed to be as follows.
Since the polyvinylidene chloride-based polymer has a high tendency to crystallize, pinholes are likely to be formed in the coating layer by the air that escapes from the paper support when the coating liquid is applied. When the coating layer containing the polyvinylidene chloride-based polymer is provided, the paper support having appropriate air permeability can suppress the falling of the coating liquid component to the paper support and is coated with the air of the paper support. It is possible to prevent the coating layer from coming off, and as a result, the occurrence of pinholes in the coating layer can be reduced.

The Garley air permeability of the paper support can be adjusted by a method conventionally known in the field of papermaking. The garley air permeability of the paper support controls, for example, the freeness of pulp beating, the linear pressure of the press of the paper machine, the calendering and its condition control, the addition of the filler to the paper material and its amount, It can be adjusted by adding the bulking agent to the paper material and its amount, adding the binder to the paper material and its amount, and a combination thereof. For example, measures such as lowering the beating degree of pulp (the value of the drainage degree is large), lowering the linear pressure of the press of the paper machine, not performing calendering or lowering the linear pressure, and reducing the amount of the binder added can be used. Decrease the value of Gurley air permeability.
The basis weight of the paper support can be adjusted according to the use of food packaging, and is not particularly limited, but is preferably ^{25 to 120 g / m 2, for example.}

The coating layer and the undercoat layer of the food packaging paper according to the above [1] and [2] and the embodiment of the present invention dependent on them (excluding the above [3]) will be described.

The food packaging paper has a paper support and at least one coating layer on one side of the paper support. In some embodiments, the coating layer is one layer. The reason for this is that it is advantageous in terms of manufacturing cost.

In some embodiments, the food packaging paper has a paper support and at least one coating layer on one side of the paper support, with an undercoat between the paper support and the coating layer. Has a layer. In at least one embodiment, the food packaging paper has a paper support and one coating layer on one side of the paper support, and an undercoat layer between the paper support and the coating layer. Has. The undercoat layer contributes to the improvement of the barrier property, the improvement of the adhesiveness between the layers, and the reduction of the occurrence of pinholes.

The undercoat layer contains a polyvinylidene chloride-based polymer containing a vinylidene chloride monomer as a main component and kaolin as a constituent unit of the resin. By containing the polyvinylidene chloride-based polymer and kaolin, the undercoat layer can not only reduce the occurrence of pinholes but also further improve the gas barrier property. Further, the undercoat layer containing the polyvinylidene chloride-based polymer and kaolin is excellent in adhesiveness to the coating layer having the polyvinylidene chloride-based polymer.

Kaolin in the undercoat layer is an industrially refined and processed kaolin ore produced naturally such as kaolinite, nacrite, dickite, halloysite, and hydrolyzed kaolinite, and is, for example, crushed, washed, iron-removed, and the like. It is manufactured through processes such as classification. In addition, kaolin is processed such as delaminated kaolin that is made into a thin plate by applying shear force to improve the aspect ratio, engineered kaolin adjusted to sharpen the particle size distribution, and calcined kaolin with enhanced cohesiveness. Highly high-quality ones are also included.

The description of the polyvinylidene chloride-based polymer of the undercoat layer is the same as that of the polyvinylidene chloride-based polymer of the coating layer, and will be described later.

In some embodiments, the content of the polyvinylidene chloride-based polymer in the undercoat layer is 40 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of kaolin in the undercoat layer per side. When the content of the polyvinylidene chloride-based polymer with respect to kaolin is in this range, the food packaging paper can further reduce the occurrence of pinholes and improve the gas barrier property.

The undercoat layer can contain various conventionally known additives in addition to kaolin and polyvinylidene chloride-based polymers, if necessary. Additives include, for example, white inorganic pigments other than kaolin, white organic pigments, various resins other than acrylic resins, polysaccharides such as starches and celluloses, surfactants, dispersants, thickeners, water retention agents, and defoamers. Examples thereof include a foaming agent and a water resistant agent.

In some embodiments, the undercoat layer contains polysaccharides such as starches and celluloses. In at least one embodiment, the content of the polysaccharide in the undercoat layer is 3 parts by mass or more and 7 parts by mass or less with respect to 100 parts by mass of kaolin in the undercoat layer per side. When the content of the polysaccharide is in this range, the food packaging paper can further reduce the occurrence of pinholes. Furthermore, in at least one embodiment, the polysaccharide is a combination of starches and celluloses. When starches and celluloses are used in combination, the food packaging paper can further reduce the occurrence of pinholes.

Starch is a starch obtained by polymerizing α-glucose by glycosidic bond, and also includes various modified starches and metal salts. Starches include, for example, esterified starches such as starches, oxidized starches, enzyme-modified starches, etherified starches, cationic starches, amphoteric starches, dialdehyde starches, phosphoric acid esterified starches, hydroxyethylated starches, and hydroxybutylated starches. And so on. Starches are one or more selected from the group consisting of these.

Cellulose is cellulose obtained by polymerizing glucose by β-1,4-glycosidic bond, and also includes various cellulose derivatives and metal salts. Examples of celluloses include cellulose ethers such as carboxymethyl cellulose, hydroxymethyl cellulose, methyl cellulose, ethyl cellulose, benzyl cellulose, trityl cellulose, cyanoethyl cellulose, carboxyethyl cellulose, amino ethyl cellulose and hydroxyethyl cellulose, nitrocellulose, cellulose acetate, cellulose nitrate, acetyl cellulose, and the like. Examples thereof include cellulose esters such as cellulose propionate, cellulose butyrate, cellulose sulfate, cellulose phosphate, cellulose acetate butyrate, cellulose nitrate butyrate, and sodium salts, potassium salts and lithium salts thereof, and hemicellulose. Celluloses are one or more selected from the group consisting of these.

In food packaging paper, at least one coating layer contains a polyvinylidene chloride-based copolymer having a vinylidene chloride monomer as a main component as a constituent unit of a resin. When the coating layer is one layer, the food packaging paper contains a polyvinylidene chloride-based copolymer having a vinylidene chloride monomer as a main component as a constituent unit of the resin.
In at least one embodiment, for a coating layer containing a polyvinylidene chloride-based copolymer, the content of the polyvinylidene chloride-based polymer in the coating layer is such that the coating layer is dried per one side of the paper support. It is 85% by mass or more with respect to the solid content. When the content of the polyvinylidene chloride-based polymer is within the above range, the polyvinylidene chloride-based polymer serves as a gas barrier agent, and the coating layer functions as a gas barrier layer. When the content of the polyvinylidene chloride-based polymer in the food packaging paper is within the above range, the gas barrier property can be improved.

The coating layer can contain various conventionally known additives, if necessary, in addition to the polyvinylidene chloride-based polymer. Additives include, for example, white inorganic pigments, white organic pigments, various resins other than polyvinyl alcohol, polysaccharides such as starches and celluloses, surfactants, dispersants, thickeners, water retention agents, defoamers, and water resistance. Agents and the like can be mentioned.

The polyvinylidene chloride-based polymer having a vinylidene chloride monomer as a main component as a constituent unit of the resin is a resin in which the vinylidene chloride monomer exceeds 50% by mass in the polymer.
In some embodiments, the polyvinylidene chloride-based polymer contained in the coating layer and the undercoat layer is a copolymer obtained by polymerizing a vinylidene chloride monomer and one or more of other monomers. .. The polyvinylidene chloride-based polymer contained in the undercoat layer and the polyvinylidene chloride-based polymer contained in the coating layer may be either the same polymer or different polymers. In at least one embodiment, the polyvinylidene chloride-based polymer contained in the undercoat layer and the polyvinylidene chloride-based polymer contained in the coating layer are the same.

In some embodiments, the polyvinylidene chloride-based polymer is a resin in which the content of the vinylidene chloride monomer exceeds 80% by mass in the polymer. In at least one embodiment, the polyvinylidene chloride-based polymer has a vinylidene chloride monomer content of 85% by mass or more in the polymer.
The polyvinylidene chloride-based polymer exhibits gas barrier properties when the content of the vinylidene chloride monomer in the polymer exceeds 50% by mass. In some embodiments, the polyvinylidene chloride-based polymer is a resin having a vinylidene chloride monomer content of 95% by mass or less in the polymer. When the content of the vinylidene chloride monomer is 95% by mass or less, rapid crystallization of polyvinylidene chloride can be suppressed during film formation of the undercoat layer and the coating layer. As a result, the undercoat layer and the coating layer can reduce the occurrence of pinholes. In some embodiments, the polyvinylidene chloride-based polymer having a vinylidene chloride monomer as a main component as a constituent unit of the resin has a vinylidene chloride monomer content of more than 50% by mass and 95% by mass in the polymer. The following resins. In at least one embodiment, the polyvinylidene chloride-based polymer having a vinylidene chloride monomer as a main component as a constituent unit of the resin has a vinylidene chloride monomer content of 85% by mass or more and 95% by mass or less in the polymer. Resin.

The other monomer is not particularly limited as long as it is a monomer copolymerizable with the vinylidene chloride monomer. Other monomers include, for example, (meth) acrylonitrile-based monomer, alkyl (meth) acrylate monomer, 2-methoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, and methoxytriethylene glycol (meth). ) Acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (Meta) acrylate, diethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, 2- (dimethylamino) ethyl (meth) acrylate, N, N-dimethylacrylamide, N-methylol (meth) acrylamide, N-vinylpyrrolidone, Examples thereof include vinyl propionate, vinyl stearate, vinyl chloride, vinyl acetate and styrene.

Examples of the (meth) acrylonitrile-based monomer include (meth) acrylonitrile, fumaronitrile, maleonitrile, 2-chloroacrylonitrile, 3-ethoxyacrylonitrile, α- (2-cyanoethyl) acrylonitrile, and the like. In some embodiments, the (meth) acrylonitrile-based monomer is (meth) acrylonitrile.

Alkyl (meth) acrylate monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth). Acrylate, t-butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Examples thereof include n-nonyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, decyl (meth) acrylate and undecyl (meth) acrylate. In some embodiments, the alkyl (meth) acrylate monomer is an alkyl (meth) acrylate monomer having an alkyl group of 1 to 4 carbon atoms.

In some embodiments, the polyvinylidene chloride-based polymer is a group consisting of (meth) acrylonitrile-based monomers, alkyl (meth) acrylate monomers, and 2-hydroxyethyl (meth) acrylates as the other monomers. It is a copolymer of one or more selected from the above and a vinylidene chloride monomer.
In some embodiments, the polyvinylidene chloride-based polymer comprises a (meth) acrylonitrile-based monomer and an alkyl (meth) acrylate monomer having 1 or more and 4 or less carbon atoms as the other monomer. It is a copolymer of one or more selected from the group and a vinylidene chloride monomer.

In some embodiments, the polyvinylidene chloride-based polymer is a copolymer comprising a vinylidene chloride monomer, a (meth) acrylonitrile-based monomer, and an alkyl (meth) acrylate monomer. In at least one embodiment, the polyvinylidene chloride-based polymer comprises one or more selected from the group consisting of vinylidene chloride monomers, (meth) acrylonitrile-based monomers, and a single amount of alkyl (meth) acrylate. It is a copolymer consisting of one or more selected from the group consisting of bodies.
Further, in some embodiments, the polyvinylidene chloride-based polymer contains a vinylidene chloride monomer, a (meth) acrylonitrile, and an alkyl (meth) acrylate monomer having 1 to 4 carbon atoms in an alkyl group. It is a coalescence. In at least one embodiment, that is, the polyvinylidene chloride-based polymer comprises one or two selected from the group consisting of vinylidene chloride monomers and (meth) acrylonitrile, and an alkyl group having 1 or more and 4 or less carbon atoms. A copolymer composed of one or more selected from the group consisting of alkyl (meth) acrylate monomers.
These reasons are that it is possible to reduce the occurrence of pinholes during film formation while having gas barrier properties.

In at least one embodiment, the polyvinylidene chloride-based polymer has a vinylidene chloride content of 85% by mass or more and 95% by mass or less, and a content of one or two selected from the group consisting of (meth) acrylonitrile of 1% by mass or more. The content of one or more selected from the group consisting of alkyl (meth) acrylate monomers having 1 or more and 4 or less carbon atoms and 10% by mass or less is 0.5% by mass or more and 5% by mass or less. ..

The molecular weight of the polyvinylidene chloride-based polymer is not particularly limited. In some examples, the molecular weight of the polyvinylidene chloride-based polymer is 80,000 or more in terms of weight average molecular weight measured by gel permeation chromatography using polystyrene having a known molecular weight as a standard substance. Within the molecular weight range, the polyvinylidene chloride-based polymer has good stability against heat and light.

The polyvinylidene chloride-based polymer can be synthesized by a known emulsion polymerization method. The synthesis is, for example, a method in which various monomers, emulsifiers and water are mixed in a predetermined reaction vessel, a radical polymerization initiator is added, and the mixture is stirred and heated. Further, the polyvinylidene chloride-based polymer is commercially available from, for example, Asahi Kasei Corporation.

In some embodiments, the food packaging paper has a paper support and at least one coating layer on one side of the paper support, wherein at least one of the coating layers is a constituent unit of the resin. Contains a polyvinylidene chloride-based polymer containing a vinylidene chloride monomer as a main component, the polyvinylidene chloride-based polymer having a vinylidene chloride monomer, (meth) acrylonitrile, and an alkyl group having 1 or more and 4 or less carbon atoms. It is a copolymer containing an alkyl (meth) acrylate monomer.
In at least one embodiment, the food packaging paper has one coating layer.
In at least one embodiment, the food packaging paper has one coating layer and has a Garley air permeability of 30 seconds or more and 200 seconds as measured according to ISO 5636-5: 2013 of the paper support. It is as follows.

In some embodiments, the food packaging paper comprises a paper support, at least one coating layer on one side of the paper support, and an undercoat layer between the paper support and the coating layer. At least one of the coating layers contains a polyvinylidene chloride-based polymer having a vinylidene chloride monomer as a main component as a constituent unit of the resin, and the undercoat layer contains vinylidene chloride as a constituent unit of the resin. The polyvinylidene chloride-based polymer containing a monomer as a main component and kaolin, and the polyvinylidene chloride-based polymer contained in the coating layer and the undercoat layer are vinylidene chloride monomer, (meth) acrylonitrile, and A copolymer containing an alkyl (meth) acrylate monomer having an alkyl group having 1 or more and 4 or less carbon atoms.
In at least one embodiment, the food packaging paper has one coating layer.
In at least one embodiment, the food packaging paper has one coating layer and has a Garley air permeability of 30 seconds or more and 200 seconds as measured according to ISO 5636-5: 2013 of the paper support. It is as follows.

In some embodiments, the amount of the undercoat layer applied is 0 g / m ² or more and 15 g / m ² or less in terms of dry solid content per side of the paper support. In some embodiments, the coating amount of the coating layer is 2 g / m ² or more and 20 g / m ² or less in terms of dry solid content per side of the paper support. In at least one embodiment, the food packaging paper has a coating amount of the undercoat layer of 0 g / m ² or more and 15 g / m ² or less in terms of dry solid content per one side of the paper support, and a coating amount of the coating layer. The dry solid content is 2 g / m ² or more and 20 g / m ² or less. The coating amount of the coating layer refers to the coating amount of the one layer when the coating layer is one layer, and refers to the total coating amount of the two or more layers.

Next, the coating layer and the undercoat layer of the food packaging paper according to the above [3] and [4] and the embodiments of the present invention that are dependent on these will be described.

The food packaging paper has a paper support and at least one coating layer on one side of the paper support, and the coating layer is the first coating layer and the first coating layer based on the paper support. A second coating layer is included on the outside of the first coating layer. For example, a food packaging paper has a paper support, a first coating layer on one side of the paper support, and a second coating layer on the outside of the first coating layer with the paper support as a reference.
The food packaging paper may have an intermediate coating layer between the first coating layer and the second coating layer for the purpose of improving the barrier property and the adhesiveness between the coating layers. In some embodiments, the coating layer is two layers, a first coating layer and a second coating layer. The reason for this is that it is more advantageous than three or more layers in terms of manufacturing cost.

In some embodiments, the food packaging paper has an undercoat layer between the paper support and the first coating layer. The undercoat layer contributes to the improvement of the barrier property, the improvement of the adhesiveness between the layers, and the reduction of the occurrence of pinholes.

The undercoat layer here is the same as the undercoat layer described in the food packaging paper according to the above [1] and [2] and the subordinate (excluding the above [3]) embodiment of the present invention. I will omit duplicate explanations.

The first coating layer contains a polyvinylidene chloride-based polymer having a vinylidene chloride monomer as a main component as a constituent unit of the resin. In at least one embodiment, the content of the polyvinylidene chloride-based polymer in the first coating layer is 85% by mass or more with respect to the dry solid content of the first coating layer per one side of the paper support. .. When the content of the polyvinylidene chloride-based polymer in the first coating layer is within the above range, the polyvinylidene chloride-based polymer becomes a gas barrier agent, and the first coating layer functions as a gas barrier layer. When the content of the polyvinylidene chloride-based polymer in the food packaging paper is within the above range, the gas barrier property is improved and the flavor barrier property can be obtained.

The first coating layer can contain various conventionally known additives in addition to the polyvinylidene chloride-based polymer, if necessary. Additives include, for example, white inorganic pigments, white organic pigments, various resins other than polyvinyl alcohol, polysaccharides such as starches and celluloses, surfactants, dispersants, thickeners, water retention agents, defoamers, and water resistance. Agents and the like can be mentioned.

The polyvinylidene chloride-based polymer contained in the first coating layer is coated on the food packaging paper according to the embodiment of the present invention, which is dependent on the above [1] and [2] and the above (excluding the above [3]). It is the same as the polyvinylidene chloride-based polymer described in the construction layer, and the overlapping description is omitted.

The second coating layer contains an acrylic resin. In at least one embodiment, the content of the acrylic resin in the second coating layer is 85% by mass or more with respect to the dry solid content of the second coating layer per one side of the paper support. When the content of the acrylic resin in the second coating layer is within the above range, the acrylic resin becomes a water and oil resistant agent and a heat sealant, and the second coating layer functions as a water and oil resistant layer and a heat seal layer. To do. That is, when the content of the acrylic resin in the food packaging paper is within the above range, water resistance, oil resistance and heat sealability can be obtained.

The acrylic resin is one or more monomers selected from the group consisting of an ethylenically unsaturated carboxylic acid-containing monomer (monomer a) and / or an alkyl (meth) acrylate monomer (single). A polymer obtained from one or more monomers selected from the group consisting of the metric b), or one or more monomers selected from the group consisting of the monomer a, and / Alternatively, one or more kinds of monomers selected from the group consisting of the monomer b and another monomer (monomer c) capable of copolymerizing with the monomer a or the monomer b. It is a copolymer obtained from one kind or two or more kinds of monomers selected from the group consisting of.

The ethylenically unsaturated carboxylic acid-containing monomer (monomer a) includes, for example, (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, monoalkyl maleic acid, monoalkyl fumaric acid, and Examples thereof include monoalkyl itaconic acid. Further, the monomer a includes, for example, a monomer in which a carboxylic acid forms a salt such as a sodium salt.

The alkyl (meth) acrylate monomer (monomer b) is, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth). Acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate and the like can be mentioned.

The monomer a or another monomer (monomer c) copolymerizable with the monomer b is, for example, styrene, vinyl acetate, vinyl chloride, (meth) acrylonitrile, ethylene, propylene, 2-. Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (Meta) acrylic rate, glycerol mono (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, dipropylene Glycoldi (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 1,3-propylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, trimethyl propantri (meth) Acrylate, tetramethylolmethanetetra (meth) acrylate, divinylbenzene, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethyl propane Tri (meth) acrylate, allyl (meth) acrylate, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide , N, N'-methylenebis (meth) acrylamide, sodium vinyl sulfonate, sodium p-styrene sulfonate, 2-acrylamide-2-methylpropane sulfonic acid, acid phosphoxyethyl (meth) acrylate ethanolamine half salt, 3- Sodium aryloxy-2-hydroxypropanesulfonate, sodium polyoxyethylene styrenated phenylsulfate, sodium glycerin monoallyl ether monosulfosuccinate, sodium 2-sulfoethyl (meth) acrylate, sodium (meth) acrylamide stearate, benzyl (meth) Acrylate, 2-methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, caprolactone change Sex (meth) acrylate, acrolein, diacetone (meth) acrylamide, formylstyrene, vinylmethylketone, vinylethylketone, (meth) acryloyloxyalkylpropenal, diacetone (meth) acrylate, acetonyl (meth) acrylate, 2-acetoacetoxy Ethyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, diallyl phthalate, triallyl cyanurate and the like can be mentioned.

Acrylic resin can be synthesized by a known emulsion polymerization method. The synthesis is, for example, a method in which various monomers, emulsifiers and water are mixed in a predetermined reaction vessel, a radical polymerization initiator is added, and the mixture is stirred and heated.

In some embodiments, the acrylic resin of the second coating layer is a polymer obtained from one or more monomers selected from the group consisting of the above-mentioned monomer b, that is, polyalkyl (meth). ) It is an acrylate. When it is a polyalkyl (meth) acrylate, the second coating layer has good adhesion and film-forming property to the first coating layer containing a polyvinylidene chloride-based polymer. As a result, the food packaging paper can improve water resistance, oil resistance and heat sealability.
In at least one embodiment, the acrylic resin of the second coating layer is one or two selected from the group consisting of methyl (meth) acrylate and one or two selected from the group consisting of 2-ethylhexyl (meth) acrylate. It is a copolymer with seeds. This is because the copolymer can obtain an improved gas barrier property against water vapor.

The second coating layer can contain various conventionally known additives in addition to the acrylic resin, if necessary. Examples of additives include white inorganic pigments, white organic pigments, various resins other than acrylic resins, polysaccharides such as starches and celluloses, surfactants, dispersants, thickeners, water retention agents, and defoamers. , Water resistant agent, colorant, ultraviolet absorber, fluorescent agent and the like.

In some embodiments, the food wrapping paper has a paper support and at least one coating layer on one side of the paper support, wherein the coating layer is a first coating layer and a paper support. A polyvinylidene chloride-based weight containing a second coating layer on the outside of the first coating layer based on the body, and the first coating layer having a vinylidene chloride monomer as a main component as a constituent unit of the resin. The second coating layer contains an acrylic resin, and the polyvinylidene chloride-based polymer contains a vinylidene chloride monomer, (meth) acrylonitrile, and an alkyl group having 1 or more and 4 or less carbon atoms. A copolymer containing an alkyl (meth) acrylate monomer, wherein the acrylic resin is selected from a group consisting of one or two selected from the group consisting of methyl (meth) acrylate and a group consisting of 2-ethylhexyl (meth) acrylate. It is a copolymer with one or two of them.
In at least one embodiment, the food packaging paper has two coating layers, a first coating layer and a second coating layer.
In at least one embodiment, the food packaging paper has two coating layers, a first coating layer and a second coating layer, and according to ISO 5636-5: 2013 of the paper support. The measured Garley air permeability is 30 seconds or more and 200 seconds or less.

In some embodiments, the food wrapping paper has a paper support and at least one coating layer on one side of the paper support, wherein the coating layer is a first coating layer and a paper support. A second coating layer is included on the outside of the first coating layer with respect to the body, and an undercoat layer is provided between the paper support and the first coating layer, and the first coating layer is provided. However, as a constituent unit of the resin, a polyvinylidene chloride-based polymer having a vinylidene chloride monomer as a main component is contained, the second coating layer contains an acrylic resin, and the undercoat layer is a resin. As a unit, it contains a polyvinylidene chloride-based polymer having a vinylidene chloride monomer as a main component and kaolin, and the polyvinylidene chloride-based polymer has a vinylidene chloride monomer, and (meth) acrylonitrile and an alkyl group have carbon atoms. A copolymer containing 1 or more and 4 or less alkyl (meth) acrylate monomers, wherein the acrylic resin is one or two selected from the group consisting of methyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. It is a copolymer with one or two selected from the group consisting of.
In at least one embodiment, the food packaging paper has two coating layers, a first coating layer and a second coating layer.
In at least one embodiment, the food packaging paper has two coating layers, a first coating layer and a second coating layer, and according to ISO 5636-5: 2013 of the paper support. The measured Garley air permeability is 30 seconds or more and 200 seconds or less.

In some embodiments, the amount of the undercoat layer applied is 0 g / m ² or more and 15 g / m ² or less in terms of dry solid content per side of the paper support. In some embodiments, the coating amount of the first coating layer is 2 g / m ² or more and 8 g / m ² or less in terms of the amount of dry solids per side of the paper support. In some embodiments, the coating amount of the second coating layer is 3 g / m ² or more and 12 g / m ² or less in terms of the amount of dry solids per side of the paper support. In at least one embodiment, the food packaging paper has a coating amount of the undercoat layer of 0 g / m ² or more and 15 g / m ² or less in terms of dry solid content per one side of the paper support, and a coating amount of the first coating layer. The dry solid content is 2 g / m ² or more and 8 g / m ² or less, and the coating amount of the second coating layer is 3 g / m ² or more and 12 g / m ² or less in terms of the dry solid content.

Food packaging paper can be manufactured by providing an undercoat layer and / or a coating layer on the paper support. The method of providing the undercoat layer and / or the coating layer on the paper support is not particularly limited. For example, a method of applying and drying an undercoat layer or a coating liquid for forming a coating layer by using a coating device and a drying device conventionally known in the papermaking field can be mentioned. Examples of the coating apparatus include a film press coater, a rod coater, an air knife coater, a rod blade coater, a bar coater, a blade coater, a gravure coater, a curtain coater, an E bar coater, a film transfer coater, and the like. Examples of drying devices include hot air dryers such as straight tunnel dryers, arch dryers, air loop dryers, and sine curve air float dryers, infrared heating dryers, and various drying devices such as dryers using microwaves. Can be done.

The coating liquid of the undercoat layer contains a polyvinylidene chloride-based polymer and kaolin, the coating liquid of the coating layer or the coating liquid of the first coating layer contains a polyvinylidene chloride-based polymer, and When the coating liquid of the second coating layer contains an acrylic resin, each layer obtained contains a polyvinylidene chloride-based polymer and kaolin, a polyvinylidene chloride-based polymer, and an acrylic resin. can do.
Food packaging paper can be used for food packaging, food bags, food containers, and the like.

Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to these examples. Here, "parts by mass" and "% by mass" represent "parts by mass" and "% by mass" of the amount of dry solids or the amount of substantial components, respectively. The coating amount of the coating layer represents the amount of dry solid content.

The embodiments of the present invention dependent on the above [1] and [2] and their dependence (excluding the above [3]) will be described by way of examples.

<Paper support>
The following paper charges were prepared.
LBKP (Drainage degree 350-480 mlcsf) 50 parts by mass NBKP (Drainage degree 350-480 mlcsf) 50 parts by mass Sulfate band 2 parts by mass Kaolin (Ancilex®, BASF) 8 parts by mass Rodin-based sizing agent (CC1404) , Seiko PMC) 0.3 parts by mass Paper chemicals 0.6 parts by mass

The paper material having the above composition was made with a long net paper machine to obtain a base paper having ^{a basis weight of 65 g / m 2.} A paper support was obtained by performing calendar processing on this using a machine calendar under the conditions of a temperature of 60 ° C. and a processing speed of 500 m / min. The ash content of the paper support was 5.5% by mass. As for the Garley air permeability of the paper support, the desired value of Garley air permeability was obtained by adjusting the drainage degree of the pulp and adjusting the press line pressure of the paper machine and the line pressure of the calendar.

The obtained food packaging paper was evaluated as follows. The garley air permeability of the paper support was measured using a B-type garley densometer manufactured by Toyo Seiki Seisakusho Co., Ltd. in accordance with ISO5636-5: 2013. The values of Garley air permeability are shown in Table 1.

<Coating liquid for undercoat layer>
The following coating liquid was prepared using water as a medium.
Pigment types and parts by mass are listed in Table 1. Resin types and parts by mass are listed in Table 1.

<Coating liquid for coating layer>
The following coating liquid was prepared using water as a medium.
Resin types are listed in Table 1/100 parts by mass

The materials appearing in Table 1 are as follows.
PVDC1: Polyvinylidene chloride-based polymer (combined mass ratio of monomer)
Vinylidene chloride: 80
Methacrylonitrile: 15
Ethyl acrylate :: 5
PVDC2: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 85
Methacrylonitrile: 10
Ethyl acrylate :: 5
PVDC3: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 90
Acrylonitrile: 9
Ethyl acrylate :: 1
PVDC4: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 95
Acrylonitrile: 3
Ethyl acrylate: 2
PVDC5: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 98
Methacrylonitrile: 1.5
Ethyl acrylate: 0.5
PVDC6: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 85
Methacrylonitrile: 10
Methyl acrylate :: 5
PVDC7: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 95
Methacrylonitrile: 3
Methyl acrylate :: 2
PVDC8: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 85
Methacrylonitrile: 10
2-Hydroxyethyl methacrylate: 5
PVA: Polyvinyl alcohol (non-denatured, completely saponified, average degree of polymerization 1700)
Ethylene-vinyl acetate-based: Ethylene-vinyl acetate copolymer Starch: Oxidized starch CMC: Sodium carboxymethyl cellulose salt Kaolin: Cumulative frequency of 2 μm or less 88% by volume kaolin

<Coating (without undercoat layer)>
The coating liquid of the coating layer was applied to one side of the paper support with an air knife coater and dried with a hot air dryer. The coater conditions were adjusted so that the coating amount of the coating layer was 8 g / m ^2.

<Coating (with undercoat layer)>
The coating liquid for the undercoat layer was applied to one side of the paper support with a rod coater and dried with a hot air dryer. The coater conditions were adjusted so that the coating amount of the undercoat layer was 10 g / m ^2. Next, the coating liquid of the coating layer was applied to the undercoat layer with an air knife coater and dried with a hot air dryer. The coater conditions were adjusted so that the coating amount of the coating layer was 8 g / m ^2.

<Pinhole>
The obtained food packaging paper was arbitrarily cut into a size of 50 cm × 50 cm. Colored toluene solution is applied to the surface of the food wrapping paper (the side having the coating layer) on the four cut food wrapping papers, and if there are pinholes, the spots that pass through the pinholes and appear on the opposite side. Was visually observed. From the observation results, the occurrence of pinholes was evaluated according to the following criteria. In the present invention, the food packaging paper can reduce the occurrence of pinholes if the evaluation is A, B, C or D.
A: No spots are found on any of the four sheets.
B: There is one pinhole visually recognized from four sheets.
C: There are two pinholes visually recognized from four.
D: There are 3 pinholes visually recognized from 4 sheets.
E: There are 4 or more pinholes visually recognized from 4 sheets.

<Gas barrier property>
The evaluation of gas barrier property was performed by ISO 1515-2: 2003 "Plastics-Film and sheeting-Determination of gas-transmission rate-Part2: Equal-pressure measurement" (JIS K7126-2: 2006 sheet-Plastic Method-Part 2: Isobaric method ”) was carried out based on the measurement results. The measurement was performed with the side not having the coating layer as the gas supply surface. Oxygen gas was used as the gas for the gas permeability test to obtain oxygen permeability, and the temperature and humidity conditions were 23 ± 0.5 ° C. and 85 ± 2% relative humidity.
In the present invention, the food packaging paper shall have a gas barrier property if it is evaluated as A, B, C or D.
A: The following oxygen permeability ^{50cc / m 2 · 24h · atm} , good.
B: Although inferior to A above,
The following oxygen transmission rate ^{100cc / m 2 · 24h · atm} , generally good.
C: Although inferior to B above,
The following oxygen transmission rate ^{125cc / m 2 · 24h · atm} , practically usable.
D: Although inferior to C above,
Oxygen permeability 150cc ^/ m 2 · 24h · atm or less, practically usable.
E: Inferior to D above,
In oxygen permeability 150cc ^/ m 2 · 24h · atm greater, practically impossible.

The evaluation results are shown in Table 2.

From Table 2, Examples 1-1 to 1-34 corresponding to the above-mentioned [1] and [2] and the embodiments of the present invention subordinate to them (excluding the above-mentioned [3]) are pinholes. It can be seen that the food packaging paper has a gas barrier property and a flavor barrier property, which can reduce the occurrence of. On the other hand, Comparative Example 1-1 and Comparative Example 1-2 which do not satisfy the configuration of the present invention are food packaging papers which can reduce the occurrence of pinholes and cannot obtain at least one of gas barrier property and flavor barrier property. I understand.
Mainly, from the comparison between Examples 1-3 and Examples 1-6 to 1-11, and the comparison between Examples 1-15 and Examples 1-19 to 1-24, the food product It can be seen that the packaging paper is preferably a polyvinylidene chloride-based polymer in which the content of the vinylidene chloride monomer in the polymer is 85% by mass or more and 95% by mass or less.
Mainly, from the comparison between Examples 1-3, 1-15, 1-29 and 1-34, the food packaging paper has an undercoat layer between the paper support and the coating layer. It can be seen that it is preferable that the undercoat layer contains a polyvinylidene chloride-based polymer and kaolin.
Mainly, from the comparison between Examples 1-1 to 1-5, and the comparison between Examples 1-15 and 1-26 to 1-29, the food packaging paper is pinhole. From the viewpoint of reducing the occurrence, it can be seen that the Garley air permeability of the paper support is preferably 30 seconds or more and 200 seconds or less.
Mainly, the comparison between Example 1-3, Example 1-7, Example 1-8, Example 1-10, Example 1-11 and Example 1-12, and Example 1-15, From the comparison between Examples 1-20, 1-21, 1-23, 1-24 and 1-25, the food wrapping paper has a polyvinylidene chloride-based weight in terms of gas barrier properties. It can be seen that it is preferable that the coalescence is a copolymer containing a vinylidene chloride monomer, a (meth) acrylonitrile-based monomer, and an alkyl (meth) acrylate monomer having an alkyl group having 1 or more and 4 or less carbon atoms.

Next, the above [3] and [4] and the embodiments of the present invention dependent on these will be described by way of examples.

<Paper support>
It was produced in the same manner as the above paper support.

The obtained food packaging paper was evaluated as follows. The garley air permeability of the paper support was measured using a B-type garley densometer manufactured by Toyo Seiki Seisakusho Co., Ltd. in accordance with ISO5636-5: 2013. The values of Garley air permeability are shown in Table 3.

<Coating liquid for undercoat layer>
The following coating liquid was prepared using water as a medium.
Pigment types and parts by mass are shown in Table 3. Resin types and parts by mass are shown in Table 3.

<Coating liquid for the first coating layer>
The following coating liquid was prepared using water as a medium.
Resin types are listed in Table 3/100 parts by mass

<Coating liquid for the second coating layer>
The following coating liquid was prepared using water as a medium.
Resin types are listed in Table 3/100 parts by mass

The materials appearing in Table 3 are as follows.
PVDC1: Polyvinylidene chloride-based polymer (combined mass ratio of monomer)
Vinylidene chloride: 80
Methacrylonitrile: 15
Ethyl acrylate :: 5
PVDC2: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 85
Methacrylonitrile: 10
Ethyl acrylate :: 5
PVDC3: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 90
Acrylonitrile: 9
Ethyl acrylate :: 1
PVDC4: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 95
Acrylonitrile: 3
Ethyl acrylate: 2
PVDC5: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 98
Methacrylonitrile: 1.5
Ethyl acrylate: 0.5
PVDC6: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 85
Methacrylonitrile: 10
Methyl acrylate :: 5
PVDC7: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 95
Methacrylonitrile: 3
Methyl acrylate :: 2
PVDC8: Polyvinylidene chloride-based polymer (composition mass ratio of monomer)
Vinylidene chloride: 85
Methacrylonitrile: 10
2-Hydroxyethyl methacrylate: 5
Acrylic A: Ethyl acrylate-n-butyl methacrylate copolymer Acrylic B: Methylmethacrylate-2-ethylhexyl (meth) Acrylic copolymer Stylic-acrylic: Acrylic-acrylic copolymer Stylic-butadiene: styrene -Butadiene copolymer PVA: Polyvinyl alcohol (unmodified, fully saponified, average degree of polymerization 1700)
Ethylene-vinyl acetate-based: Ethylene-vinyl acetate copolymer Starch: Oxidized starch CMC: Sodium carboxymethyl cellulose salt Kaolin: Cumulative frequency of 2 μm or less 88% by volume kaolin

<Coating (without undercoat layer)>
The coating liquid of the first coating layer was applied to one side of the paper support with an air knife coater and dried with a hot air dryer. The coater conditions were adjusted so that the coating amount of the first coating layer was 5 g / m ^2. Subsequently, the coating liquid of the second coating layer was coated with a rod coater and dried with a hot air dryer with respect to the first coating layer. The coater conditions were adjusted so that the coating amount of the second coating layer was 6 g / m ^2.

<Coating (with undercoat layer)>
The coating liquid for the undercoat layer was applied to one side of the paper support with a rod coater and dried with a hot air dryer. The coater conditions were adjusted so that the coating amount of the undercoat layer was 10 g / m ^2. Next, the coating liquid of the first coating layer was applied to the undercoat layer with an air knife coater and dried with a hot air dryer. The coater conditions were adjusted so that the coating amount of the first coating layer was 5 g / m ^2. Subsequently, the coating liquid of the second coating layer was coated with a rod coater and dried with a hot air dryer with respect to the first coating layer. The coater conditions were adjusted so that the coating amount of the second coating layer was 6 g / m ^2.

<Pinhole>
The obtained food packaging paper was arbitrarily cut into a size of 50 cm × 50 cm. Colored toluene solution is applied to the surface of the food wrapping paper (the side having the first coating layer and the second coating layer) on the four cut food wrapping papers, and if there are pinholes, they pass through the pinholes. Then, the spots appearing on the opposite side were visually observed. From the observation results, the occurrence of pinholes was evaluated according to the following criteria. In the present invention, the food packaging paper can reduce the occurrence of pinholes if the evaluation is A, B, C or D.
A: No spots are found on any of the four sheets.
B: There is one pinhole visually recognized from four sheets.
C: There are two pinholes visually recognized from four.
D: There are 3 pinholes visually recognized from 4 sheets.
E: There are 4 or more pinholes visually recognized from 4 sheets.

<Water resistance>
In the evaluation of water resistance, about 2 ml of water droplets are dropped on the surface of the food wrapping paper (the side having the first coating layer and the second coating layer), and the dropped water is the surface of the food wrapping paper (first coating). The degree of penetration on the side having the work layer and the second coating layer) and the degree of seepage on the back surface of the food packaging paper (the side having no first coating layer and the second coating layer) were visually observed. .. From the observation results, the water resistance was evaluated according to the following criteria. In the present invention, the food packaging paper shall have water resistance if it is evaluated as A or B.
A: There is no penetration and no exudation is observed.
B: Slight penetration is observed. However, no exudation is observed.
C: Penetration is observed. In addition, exudation is observed.

<Oil resistance>
The oil resistance is evaluated by dropping about 1 ml of oil droplets of salad oil on the surface of the food packaging paper (the side having the first coating layer and the second coating layer), and the dropped oil is the surface of the food packaging paper (the side having the first coating layer and the second coating layer). Visually observe the degree of penetration on the side with the first coating layer and the side with the second coating layer and the degree of exudation on the back surface of the food packaging paper (the side without the first coating layer and the second coating layer). I went. From the observation results, the oil resistance was evaluated according to the following criteria. In the present invention, the food packaging paper shall have oil resistance if it is evaluated as A or B.
A: There is no penetration and no exudation is observed.
B: Slight penetration is observed. However, no exudation is observed.
C: Penetration is observed. In addition, exudation is observed.

<Gas barrier property>
The evaluation of gas barrier property was performed by ISO 1515-2: 2003 "Plastics-Film and sheeting-Determination of gas-transmission rate-Part2: Equal-pressure measurement" (JIS K7126-2: 2006 sheet-Plastic Method-Part 2: Isobaric method ”) was carried out based on the measurement results. The measurement was performed with the side having no first coating layer and the second coating layer as the gas supply surface. Oxygen gas was used as the gas for the gas permeability test to obtain oxygen permeability, and the temperature and humidity conditions were 23 ± 0.5 ° C. and 85 ± 2% relative humidity.
In the present invention, the food packaging paper shall have a gas barrier property if it is evaluated as A, B, C or D.
A: The following oxygen permeability ^{50cc / m 2 · 24h · atm} , good.
B: Although inferior to A above,
The following oxygen transmission rate ^{100cc / m 2 · 24h · atm} , generally good.
C: Although inferior to B above,
The following oxygen transmission rate ^{125cc / m 2 · 24h · atm} , practically usable.
D: Although inferior to C above,
Oxygen permeability 150cc ^/ m 2 · 24h · atm or less, practically usable.
E: Inferior to D above,
In oxygen permeability 150cc ^/ m 2 · 24h · atm greater, practically impossible.

<Flavor barrier property>
Commercially available regular coffee powder was used as the aroma generating substance. Regular coffee powder was placed in a glass cup, the opening of the cup was covered with food wrapping paper, and the circumference of the opening was tightly sealed with tape. Five subjects were sniffed at the opening of a cup sealed with food packaging paper and sensory evaluated according to the following criteria.
3 points: I don't feel the smell.
2 points: I feel like I smell it.
1 point: I feel the smell.
Based on the results of the sensory evaluation of 5 people, the flavor barrier property was evaluated according to the following criteria. In the present invention, the food packaging paper shall have a flavor barrier property if the evaluation is A or B.
A: Evaluation 3 is 3 or more and evaluation 1 is 0.
B: Evaluation 2 is 3 or more and evaluation 1 is 0.
C: Evaluation 1 is 1 or more.

<Heat seal suitability>
Using two sheets of food wrapping paper, the surfaces of the food wrapping paper having the first coating layer and the second coating layer face each other, and the pressure is 0.5 MPa, 130 ° C., 1 second with a heat sealer. Heat-sealed by.
A heat-sealed food packaging paper is cut out to a width of 15 mm and allowed to stand at a temperature of 23 ° C. and a relative humidity of 50% for 24 hours. The heat seal suitability was evaluated by measuring. The measurement was performed with 5 parts of the sample, and the average value of 5 parts was used. From the measured values, the heat seal suitability was evaluated according to the following criteria. In the present invention, the food packaging paper shall have heat seal suitability if it is evaluated as A, B or C.
A: The value is 10N / 15mm or more.
B: The value is 6N / 15mm or more and less than 10N / 15mm.
C: The value is 3N / 15mm or more and less than 6N / 15mm.
D: The value is less than 3N / 15mm.

The evaluation results are shown in Table 4.

From Table 4, Examples 2-1 to 2-38 corresponding to the above [3] and [4] and the embodiments of the present invention subordinate to them have water resistance, oil resistance, and gas barrier property. It can be seen that the food packaging paper has a flavor barrier property, can reduce the occurrence of pinholes, and has heat seal suitability. On the other hand, it can be seen that Comparative Examples 2-1 to 2-3 that do not satisfy the configuration of the present invention are food packaging papers that do not satisfy any of these effects.
Mainly, from the comparison between Examples 2-3 and Examples 2-6 to 2-11, and the comparison between Examples 2-17 and 2-21 to 2-26, the food product. From the viewpoint of gas barrier properties, it can be seen that the content of the vinylidene chloride monomer in the polyvinylidene chloride polymer is preferably 85% by mass or more and 95% by mass or less in the wrapping paper.
Mainly, from the comparison between Examples 2-3, 2-17, 2-33 and 2-38, the food packaging paper has an undercoat layer between the paper support and the coating layer. It can be seen that it is preferable that the undercoat layer contains a polyvinylidene chloride-based polymer and kaolin.
Mainly, from the comparison between Examples 2-1 to 2-5, and the comparison between Examples 2-17 and 2-30 to 2-33, the food packaging paper is pinhole. From the viewpoint of reducing the occurrence, it can be seen that the Garley air permeability of the paper support is preferably 30 seconds or more and 200 seconds or less.
Mainly, from the comparison between Example 2-3, Example 2-7, Example 2-8, Example 2-10, Example 2-11 and Example 2-12, the food wrapping paper has a gas barrier property. In this respect, the polyvinylidene chloride-based polymer is a copolymer containing a vinylidene chloride monomer, a (meth) acrylonitrile-based monomer, and an alkyl (meth) acrylate monomer having an alkyl group having 1 or more and 4 or less carbon atoms. It turns out that it is preferable to have it.

Claims

It has a paper support and at least one coating layer on one side of the paper support.
A food packaging paper in which at least one of the coating layers contains a polyvinylidene chloride-based polymer containing a vinylidene chloride monomer as a main component as a constituent unit of a resin.
The food packaging paper according to claim 1, wherein the coating layer is one layer.
The coating layer includes a first coating layer and a second coating layer on the outside of the first coating layer with the paper support as a reference.
The first coating layer contains a polyvinylidene chloride-based polymer containing a vinylidene chloride monomer as a main component as a constituent unit of the resin.
The food packaging paper according to claim 1, wherein the second coating layer contains an acrylic resin.
It has a paper support, a first coating layer on one side of the paper support, and a second coating layer on the outside of the first coating layer with the paper support as a reference.
The first coating layer contains a polyvinylidene chloride-based polymer containing a vinylidene chloride monomer as a main component as a constituent unit of the resin.
A food packaging paper in which the second coating layer contains an acrylic resin.
The food packaging paper according to claim 4, wherein in the polyvinylidene chloride-based polymer, the content of the vinylidene chloride monomer in the polymer is 85% by mass or more and 95% by mass or less.
A polyvinylidene chloride-based polymer having an undercoat layer between the paper support and the first coating layer and having a vinylidene chloride monomer as a main component of the undercoat layer as a constituent unit of the resin. The food packaging paper according to claim 4 or 5, which contains kaolin.
The food packaging paper according to any one of claims 4 to 6, wherein the garley air permeability of the paper support measured according to ISO 5636-5: 2013 is 30 seconds or more and 200 seconds or less.
The polyvinylidene chloride-based polymer is a copolymer containing a vinylidene chloride monomer, a (meth) acrylonitrile-based monomer, and an alkyl (meth) acrylate monomer having an alkyl group having 1 or more and 4 or less carbon atoms. The food wrapping paper according to any one of claims 4 to 7.
The food packaging paper according to any one of claims 1 to 3, wherein the content of the vinylidene chloride monomer in the polymer is 85% by mass or more and 95% by mass or less in the polyvinylidene chloride-based polymer.
A polyvinylidene chloride-based polymer having an undercoat layer between the paper support and the coating layer and having a vinylidene chloride monomer as a main component as a constituent unit of the resin, and kaolin The food packaging paper according to any one of claims 1 to 3 and 9.
The food packaging paper according to any one of claims 1 to 3, 9 and 10, wherein the garley air permeability of the paper support is 30 seconds or more and 200 seconds or less, which is measured according to ISO 5636-5: 2013.
The polyvinylidene chloride-based polymer is a copolymer containing a vinylidene chloride monomer, a (meth) acrylonitrile-based monomer, and an alkyl (meth) acrylate monomer having an alkyl group having 1 or more and 4 or less carbon atoms. The food wrapping paper according to any one of claims 1 to 3 and 9 to 11.