JP6809438B2 - Foam insulation paper container Paper base material manufacturing method, foam insulation paper container sheet manufacturing method, foam insulation paper container manufacturing method and foam insulation paper container paper base material - Google Patents

Description

The present invention relates to a method for producing a foam-insulated paper container paper base material, a method for producing a foam-insulated paper container sheet, a method for producing a foam-insulated paper container, and a foam-insulated paper container paper base material.

Insulation containers are used as containers for providing hot beverages such as coffee and hot foods such as soup to purchasers in fast food stores, trains, vending machines, etc., or as containers for instant noodles in cups. Has been done.

Conventionally, a expanded polystyrene container is known as a heat insulating container used for such an application. A expanded polystyrene container is manufactured by injecting a raw material in which a foaming agent is added to polystyrene into a mold, applying heat and pressure to the raw material to foam the raw material, and molding the container. The expanded polystyrene container obtained in this way is bulky because the entire container is foamed, and is very excellent in terms of heat insulation, but there is a problem that the amount of dust after use increases. is there. Further, since the expanded polystyrene container generates high heat when it is incinerated, there is a concern that it may affect the incinerator. Furthermore, from the viewpoint of saving petroleum resources, it is required to review its use.

Further, since there are many minute irregularities on the outer surface of the expanded polystyrene container, there is a problem that it is difficult to clearly express even if a pattern, characters, symbols, etc. are printed on the outer surface of the container. Furthermore, since expanded polystyrene containers are weaker than paper heat-insulating containers, when used as relatively large containers such as cup-filled instant noodle containers, there is a problem that cracks occur during transportation. there were.

The following prior arts are disclosed for these problems. For example, in Patent Document 1, in a foam insulating paper container sheet in which a thermoplastic resin layer such as polyethylene is laminated on at least one side of a paper base material, the surface of the paper base material is treated by a calendar size press. Sheets for paper containers are disclosed.
Further, Patent Document 1 discloses a container made of foamed heat insulating paper using the above-mentioned sheet for a container made of foamed heat insulating paper as a body member and / or a bottom plate member. The foamed heat insulating paper container is obtained by heating and evaporating the water contained in the paper base material of the foamed heat insulating paper container sheet and foaming the thermoplastic resin layer.

Japanese Unexamined Patent Publication No. 2012-21408

In the foamed heat insulating paper container described in Patent Document 1, since the main base material is paper, the amount of petroleum used is smaller and the environmental load is smaller than that of the container made entirely of expanded polystyrene. However, in the foamed heat insulating paper container described in Patent Document 1, since the permeation amount of water vapor generated from the paper base material during heat foaming is not uniform depending on the location, the foaming of the thermoplastic resin layer becomes non-uniform, and the surface is beautiful. It left room for improvement in sexuality.
In addition, the foamed heat insulating paper container is naturally required to have heat insulating properties.

The present invention has been made in view of the above circumstances. That is, the present invention is a method for producing a foam insulating paper container paper base material, a method for producing a foam insulating paper container sheet, and a method for manufacturing a foam insulating paper container, which are excellent in heat insulating properties and surface beauty of the foam insulating paper container. An object of the present invention is to provide a foam insulating paper container paper base material.

The present inventors have studied a method for producing a paper base material before laminating a thermoplastic resin layer to be a foamed resin layer. When a water-soluble resin layer is provided on the surface of the paper base material, it is possible to appropriately barrier the permeation of water vapor generated from the paper base material during heat foaming and reduce the variation in the amount of water vapor permeation depending on the location. Then, by using a specific coating device as the coating method of the water-soluble resin layer, it becomes possible to uniformly control the coating amount and the permeation thickness of the water-soluble resin into the paper base material, and the foamed heat insulating paper. We have found that the heat insulation and beauty of the container can be improved, and have completed the present invention. The present invention has the following configuration.

(1) A method for producing a foam-insulated paper container paper base material, wherein a water-soluble resin is applied to at least one side of a paper base material using a blade coater or a rod coater to form a water-soluble resin layer. Foam insulation characterized in that the amount of the sex resin layer formed per one side is 0.05 to 6.0 g / m ² , and the permeation thickness of the water-soluble resin into the paper substrate is 5 to 50 μm. Paper container A method for manufacturing a paper base material.

(2) The method for producing a foamed heat insulating paper container paper base material according to (1), wherein the water-soluble resin contains at least one selected from polyvinyl alcohol, starches and polyacrylamides.

(3) The method for producing a foam-insulated paper container paper base material according to (1) or (2), wherein the air permeation resistance per basis weight is 1.5 to 6.0 s / g / m ² .

(4) A method for producing a sheet for a foam-insulated paper container having a thermoplastic resin layer on at least one side of a paper base material, wherein a water-soluble resin is applied to at least one side of the paper base material using a blade coater or a rod coater. It has a foam insulating paper container paper base material forming step of coating to form a water-soluble resin layer, and a foam insulating paper container sheet forming step of forming the thermoplastic resin layer on the water-soluble resin layer. The amount of the water-soluble resin layer formed per one side is 0.05 to 6.0 g / m ² , and the penetration thickness of the water-soluble resin into the paper substrate is 5 to 50 μm. A method for manufacturing a sheet for a foam insulating paper container.

(5) A method for manufacturing a foam-insulated paper container using foam-insulated paper on at least one of a body member and a bottom plate member, wherein a water-soluble resin is coated on at least one side of a paper base material using a blade coater or a rod coater. A foam insulating paper container paper base material forming step of forming a water-soluble resin layer by working, a foam insulating paper container sheet forming step of forming a thermoplastic resin layer on the water-soluble resin layer, and the foam insulating paper. It has a paper container molding step of molding a paper container using a container sheet and a foamed heat insulating paper container forming step of heat-treating the paper container to form a foamed heat insulating paper container, and has one side of the water-soluble resin layer. A method for producing a foam-insulated paper container, characterized in that the amount formed per paper is 0.05 to 6.0 g / m ² and the permeation thickness of the water-soluble resin into the paper substrate is 5 to 50 μm. ..

(6) A foam-insulated paper container paper base material having a water-soluble resin layer containing a water-soluble resin coated by a blade coater or a rod coater on at least one side of the paper base material, the water-soluble resin layer. A foam-insulated paper container paper base characterized in that the amount formed per side is 0.05 to 6.0 g / m ² and the penetration thickness of the water-soluble resin into the paper substrate is 5 to 50 μm. Material.

According to the method for producing a foamed heat insulating paper container paper base material, the method for manufacturing a sheet for foamed heat insulating paper container, and the method for manufacturing a foamed heat insulating paper container of the present invention, the thermoplastic resin layer is uniformly foamed to provide heat insulating properties and a beautiful surface. A foam-insulated paper container having excellent properties can be obtained. The foamed heat insulating paper container paper base material of the present invention can produce a foamed heat insulating paper container having excellent heat insulating properties and surface beauty.

It is a schematic cross-sectional view of the foam insulation paper container which concerns on this embodiment. It is an enlarged sectional view of the part shown by A of FIG. It is a schematic cross-sectional view of the foam insulation paper container paper base material which concerns on this embodiment. It is a schematic cross-sectional view of the sheet for foam insulation paper container which concerns on this embodiment.

Embodiments of the present invention will be described below. However, the embodiments of the present invention are not limited to the following embodiments.

FIG. 1 is a schematic cross-sectional view of the foamed heat insulating paper container according to the present embodiment. Further, FIG. 2 is an enlarged cross-sectional view of the portion shown by A in FIG. As shown in FIG. 1, in the foam insulating paper container 8 in the present embodiment, the foam insulating paper 20 is used for the body member 6 and the bottom plate member 7. The foamed heat insulating paper 20 may be used for either the body member 6 or the bottom plate member 7. As shown in FIG. 2, the foamed heat insulating paper 20 has a foamed resin layer 9 made of a thermoplastic resin on at least one side of the paper base material 1. The foamed heat insulating paper 20 has a water-soluble resin layer 2 between the paper base material 1 and the foamed resin layer 9. In FIG. 2, the water-soluble resin layer 2 is formed on both surfaces of the paper base material 1. Further, the foamed heat insulating paper 20 has the foamed resin layer 9 described above on the outer wall surface side thereof, and has a melting point thermoplastic resin layer 10 described later on the inner wall surface side thereof.

FIG. 3 is a schematic cross-sectional view of the foam insulating paper container sheet according to the present embodiment. The foam insulating paper container sheet 5 according to the present embodiment is used for manufacturing the foam insulating paper 20 described above. The foam-insulated paper container sheet 5 according to the present embodiment has a thermoplastic resin layer 4 on at least one side of the paper base material 1, and is water-soluble between the paper base material 1 and the thermoplastic resin layer 4. It has a resin layer 2. The thermoplastic resin layer 4 is foamed by heat treatment to become a foamed resin layer 9 (see FIG. 2).

FIG. 4 is a schematic cross-sectional view of the foamed heat insulating paper container paper base material according to the present embodiment. The foamed heat insulating paper container paper base material 3 according to the present embodiment is used for manufacturing the foamed heat insulating paper container sheet 5. The foamed heat insulating paper container paper base material 3 according to the present embodiment has a water-soluble resin layer 2 on at least one side of the paper base material 1. By providing the thermoplastic resin layer 4 on the water-soluble resin layer 2, the foam-insulated paper container sheet 5 is formed.

The foam-insulated paper container sheet 5 is used as the body member 6 and the bottom plate member 7 to form a paper container. After that, by heating the paper container, the water contained in the paper base material 1 and the water-soluble resin layer 2 is vaporized to become water vapor. The generated water vapor permeates through the water-soluble resin layer 2 and permeates into the heated thermoplastic resin layer 4, foams the thermoplastic resin, and the thermoplastic resin layer 4 changes to the foamed resin layer 9. As a result, the paper container becomes an effervescent heat-insulating paper container 8 having heat insulating properties.

[Effervescent heat insulating paper container paper base material]
The foam-insulated paper container paper base material 3 has a paper base material 1 and a water-soluble resin layer 2 on at least one side thereof. If the water-soluble resin layer 2 is not formed on the surface of the paper base material 1, water vapor is directly released from the paper base material 1 when heated, so that the amount of water vapor permeated depends on the location of the paper base material 1. It becomes uniform, and there is a tendency that superfoaming is likely to occur partially in the foaming of the thermoplastic resin layer 4. If the over-foamed portion is present, the foamed form becomes non-uniform and the surface becomes uneven, so that both the heat insulating property of the foamed heat insulating paper container 8 and the beauty of the surface are deteriorated.
Hereinafter, each member constituting the present embodiment will be described.

(Water-soluble resin)
The water-soluble resin is a resin that dissolves in water. The water-soluble resin is not particularly limited as long as it is a water-soluble polymer having a film-forming property. Examples of the water-soluble resin include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, polyvinyl alcohol such as modified polyvinyl alcohol, starches, polyacrylamides, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, acetyl cellulose and the like. Cellulose ethers and derivatives thereof, and the like. These can be used alone or in combination of two or more.

Among the water-soluble resins, it is preferable to contain at least one selected from polyvinyl alcohol, starches and polyacrylamides from the viewpoint of processability.

(Polyvinyl alcohol)
Polyvinyl alcohol is represented by the chemical formula [-CH ₂ CH (OH)-] _n [-CH ₂ CH (OCOCH ₃ )-] _m , and is called PVOH, PVA, Poval, or the like. Polyvinyl alcohol is generally produced by saponifying a polyvinyl acetate resin obtained by polymerizing a vinyl acetate monomer. In the chemical formula, n indicates a saponified portion and m indicates an unsaponified portion.

As the polyvinyl alcohol, partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol (in this embodiment, those having a saponification degree of 90 mol% or more) can be used. The average degree of polymerization is represented by n + m, and the saponification degree (mol%) is represented by {n / (n + m)} × 100. The average degree of polymerization can be arbitrarily adjusted depending on how much the vinyl acetate monomer is bonded in the step of polymerizing the vinyl acetate monomer. The degree of saponification can be arbitrarily adjusted depending on how much the vinyl acetate unit is converted into a hydroxyl group in the step of saponifying the polyvinyl acetate resin. The average degree of polymerization and the degree of saponification can be measured according to JIS K 6726-1994.

Further, as the polyvinyl alcohol, an unmodified polyvinyl alcohol in which a functional group other than a hydroxyl group (OH group) and an acetic acid group (OCOCH ₃ groups) is not introduced can be used. Further, as the polyvinyl alcohol, a modified polyvinyl alcohol into which a functional group other than a hydroxyl group or an acetic acid group has been introduced can also be used. Examples of the functional group introduced into the modified polyvinyl alcohol include a carboxyl group, a carbonyl group, a sulfonic acid group, a silanol group, a cationic group, and an alkyl group. That is, examples of the modified polyvinyl alcohol include polyvinyl alcohols such as carboxyl-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, cationic-modified polyvinyl alcohol, and terminal alkyl-modified polyvinyl alcohol.

The reason why polyvinyl alcohol is excellent as a material for a film to be formed on the paper substrate 1 is considered as follows. In polyvinyl alcohol, a hydrophilic functional group (hydroxyl group) and a hydrophobic functional group (acetic acid group) coexist appropriately in the polymer molecule, so that a film firmly adhered to the paper substrate 1 is formed. At the same time, the water vapor can be appropriately barriered. Therefore, when the polyvinyl alcohol layer that is firmly adhered to the paper base material 1 is formed, the amount of water vapor permeation can be appropriately controlled, and the amount of water vapor permeation can be suppressed from varying depending on the location. As a result, the foamed state of the thermoplastic resin layer 4 can be made uniform, and the heat insulating property can be improved.

The average degree of polymerization of polyvinyl alcohol is preferably 300 to 4000, more preferably 500 to 3000, and even more preferably 1000 to 2000 when measured in accordance with JIS K 6726-1994. By setting the average degree of polymerization to 300 or more, the film forming property is improved. Further, by setting the average degree of polymerization to 4000 or less, the solubility in water is improved, the viscosity of the solution does not increase, and the coating becomes easy.

The saponification degree of polyvinyl alcohol is preferably 80 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more. When the saponification degree is 80 mol% or more, the water solubility is increased and the film forming property is improved. Polyvinyl alcohol can be appropriately selected and used from commercially available ones.

(Starch)
Examples of starches include unmodified starch, enzyme-modified starch, thermochemically modified starch, oxidized starch, esterified starch, etherified starch (for example, hydroxyethylated starch), cationized starch and the like.

(Polyacrylamides)
Examples of polyacrylamides include polyacrylamide, cationic polyacrylamide, anionic polyacrylamide, amphoteric polyacrylamide, nonionic polyacrylamide and the like. Examples of the cationic polyacrylamide include polyacrylamide having a functional group such as an amino group, a quaternary ammonium salt, and an azetidineium ring. Examples of the anionic polyacrylamide include polyacrylamide having a carboxyl group, a sulfone group and the like. Examples of the nonionic polyacrylamide include polyacrylamide having a hydroxyl group, an amide group and the like. Amphoteric polyacrylamide is a polyacrylamide having both cationic and anionic functional groups.

(Water-soluble resin layer)
The water-soluble resin layer 2 can be provided on at least one side of the paper base material 1, and can also be provided on both sides of the paper base material 1. When the water-soluble resin layer 2 firmly adhered to the paper base material 1 is formed, the amount of water vapor permeation can be appropriately controlled and the variation in the amount of water vapor permeation depending on the location can be reduced. As a result, the foamed state of the thermoplastic resin layer 4 can be made uniform, and the heat insulating property of the foamed heat insulating paper container 8 can be improved.

Further, as will be described later, polyethylene is often used as the thermoplastic resin to be the foamed resin layer 9. Due to the presence of the water-soluble resin layer 2 on the surface of the paper base material 1, the thermoplastic resin laminated on the water-soluble resin layer 2 in the subsequent process is firmly adhered to the paper base material 1. As a result, the amount of water vapor permeated from the paper base material 1 at the time of foaming becomes more uniform, overfoaming of the thermoplastic resin is suppressed, and the foaming form becomes uniform.

The water-soluble resin layer 2 is a layer containing a water-soluble resin as a main component, but if necessary, other resin components may be appropriately contained as long as the effects of the invention are not impaired.

[Manufacturing method of foam insulation paper container paper base material]
The present inventors have repeatedly studied a method for producing a foamed heat insulating paper container paper base material 3 in which a water-soluble resin layer 2 is formed on at least one side of the paper base material 1. As a result, by adopting a coating method of coating the water-soluble resin using a blade coater or a rod coater as a method of forming the water-soluble resin layer 2, the coating amount of the water-soluble resin and the paper base material 1 are covered. It was found that it is possible to uniformly control the permeation thickness of the plastic. Then, by forming the water-soluble resin layer 2 in which the coating amount of the water-soluble resin and the penetration thickness into the paper base material 1 are within a predetermined range, the heat insulating property and the surface beauty of the foamed heat insulating paper container 8 can be improved. We found that we were both satisfied. That is, in the present embodiment, a blade coater or a rod coater is used as an apparatus for applying or impregnating the paper substrate 1 with the coating liquid containing the water-soluble resin.

The blade coater is a coating that is supplied and adhered to the paper base material 1 by holding the backing roll and passing it through the paper base material 1 and discharging it from the slit-shaped opening or transferring it through the applicator roll. It is a device that applies the work liquid by measuring it with a blade so that only the required amount remains and scraping it off. That is, a blade (plate blade) having a length that crosses the paper base material 1 cannot pass through the gap between the paper base material 1 and the blade by tilting and arranging the blades (plate blades) in close proximity to the paper base material 1. This coater is a method in which excess coating liquid is scraped off with a blade, adjusted to a predetermined coating amount, and applied.

Like the blade coater, the rod coater is a smooth rod, a rod around which a wire is wound, or has a large number of grooves on the surface of a coating liquid supplied and adhered to the paper substrate 1 via an applicator roll or the like. It is a device that applies by scraping with a rod, and is also called a bar coater. That is, a rod having a length that crosses the paper base material 1 is arranged close to the paper base material 1, and an excess coating liquid that cannot pass through the gap between the paper base material 1 and the rod is removed by the rod. It is a coater of the method of scraping off and adjusting to a predetermined coating amount. Above all, in order not to increase the penetration thickness of the water-soluble resin into the paper base material 1 more than necessary, it is preferable to apply a high-concentration coating liquid using a smooth rod.

Both the blade coater and the rod coater can apply the coating liquid at high speed and smoothly, and can apply a high-concentration coating liquid thinly and uniformly. Therefore, a relatively high-concentration coating liquid containing a water-soluble resin can be applied on the paper substrate 1 to a thin and uniform thickness. A high-concentration coating liquid containing a water-soluble resin has a high solution viscosity, so that the coating liquid is suppressed from permeating into the paper base material 1 after coating on the paper base material 1. Therefore, the penetration thickness of the water-soluble resin into the paper base material 1 can be reduced. Further, when a high-concentration coating liquid is used, the water-soluble resin concentration in the water-soluble resin layer 2 can be increased. From the above, even if the amount of the water-soluble resin applied is reduced, the water vapor generated from the paper substrate 1 can be uniformly and effectively barriered.

Of the blade coater and the rod coater, the blade coater is preferable because the linear pressure at the time of scraping is higher than that of the rod coater, the coating amount can be adjusted precisely, and the film thickness is excellent in uniformity.

Conventionally used coaters include calendar size presses and two-roll size presses. In these coaters, in order to form a thin coating film, it was necessary to reduce the concentration of the water-soluble resin to lower the solution viscosity. As a result, the coating liquid penetrates deeper into the paper base material 1, and the concentration of the water-soluble resin in the water-soluble resin layer 2 is also low, which is inferior in the ability to barrier water vapor generated from the paper base material 1. It became.

In defining the foamed heat insulating paper container paper base material 3 having the water-soluble resin layer 2 containing the water-soluble resin coated by the blade coater or the rod coater, the difference from the coaters and the like conventionally used is different. Since it is difficult to specify quantitatively and it is practically difficult to directly specify it by its structure and characteristics, the method specified by the manufacturing method of the product was adopted.

Water is usually used as the solvent for the coating liquid. If necessary, an organic solvent such as alcohol, which is soluble in water, may be mixed and used. The coating liquid may contain surfactants, defoamers, dyes, pigments, sizing agents, water resistant agents, paper strength enhancers, dispersants, plastics, pH adjusters, defoaming agents, and water retention agents, if necessary. Various known auxiliaries such as agents, preservatives, coloring dyes, coloring pigments, and ultraviolet inhibitors may be used in combination.

The method of drying the coating layer after applying the coating liquid is not particularly limited, and may be appropriately selected from known methods used in the papermaking step or the drying step. Further, after the water-soluble resin layer 2 is formed, a smoothing treatment can be performed if necessary. The smoothing process is performed on-machine or off-machine using a smoothing process device such as a normal super calendar, gloss calendar, or soft calendar.

(Amount of water-soluble resin layer formed)
The amount of the water-soluble resin layer 2 formed per one side is 0.05 to 6.0 g / m ² in terms of solid content, more preferably 0.08 to 2.0 g / m ² . When the amount of the water-soluble resin layer 2 formed is in this range, the thermoplastic resin layer 4 can be uniformly foamed, the thickness after foaming can be increased, and the heat insulating property is improved. Further, when the amount of the water-soluble resin layer 2 formed is within this range, the amount formed is appropriate, so that when the thermoplastic resin layer 4 is foamed, large irregularities and the like are unlikely to occur on the surface, and the beauty can be improved. it can. Further, when the amount of the water-soluble resin layer 2 formed is within this range, it is possible to reduce equipment stains in the papermaking process or the drying process when applying the coating liquid, and the stains fall off to cause foreign matter in the foamed heat insulating paper container 8. It is possible to prevent it from being mixed. If the amount of the water-soluble resin layer 2 formed on one side is less than 0.05 g / m ² , uniform foaming may not be obtained and the surface may be uneven, resulting in poor aesthetics. On the other hand, if the amount of the water-soluble resin layer 2 formed per one side exceeds 6.0 g / m ² , the thermoplastic resin cannot be sufficiently foamed, and the heat insulating property may be inferior. The amount of the water-soluble resin layer 2 formed can be measured from the amount of weight change before and after the formation.

(Thickness of water-soluble resin permeating into paper substrate)
When the coating liquid containing the water-soluble resin is applied to the paper base material 1, the coating liquid permeates from the surface of the paper base material 1 toward the inside. Then, the coating liquid is dried to solidify, and the water-soluble resin layer 2 is formed. In the present embodiment, the water-soluble resin that has penetrated into the paper substrate 1 and solidified is also regarded as a part of the water-soluble resin layer 2.

The permeation thickness of the water-soluble resin into the paper substrate 1 is 5 to 50 μm, preferably 10 to 35 μm, more preferably 15 to 25 μm. When the permeation thickness of the water-soluble resin into the paper base material 1 is within this range, the thermoplastic resin layer 4 can be uniformly foamed, the thickness after foaming can be increased, and the heat insulating property is improved. To do. Further, when the permeation thickness of the water-soluble resin into the paper base material 1 is within this range, the permeation of water vapor generated from the paper base material 1 can be appropriately barriered, so that the variation in the amount of water vapor permeation depending on the location can be reduced. .. As a result, the foam cells can be formed small and homogeneously, and the flatness and beauty of the surface can be improved. If the permeation thickness of the water-soluble resin into the paper substrate 1 is less than 5 μm, the water-soluble resin layer 2 excessively barriers the permeation of water vapor, so that the thermoplastic resin layer 4 can be sufficiently foamed. This may not be possible and may reduce heat insulation. On the other hand, if the permeation thickness of the water-soluble resin into the paper base material 1 exceeds 50 μm, the amount of water vapor permeation may not be uniform, the foaming may be non-uniform, and the beauty may be deteriorated. The penetration thickness of the water-soluble resin into the paper substrate 1 can be appropriately adjusted depending on the pressure of the blade or rod, the gap size between the blade or rod and the paper, the angle of the blade, the viscosity of the coating liquid, and the like. The penetration thickness of the water-soluble resin into the paper substrate 1 can be measured from an enlarged photograph of the cross section using an optical microscope, a scanning electron microscope, or the like.

(Paper base material)
The paper substrate 1 is usually composed of pulp. The type of pulp constituting the paper base material 1 is not particularly limited. Examples of pulp types include coniferous bleached kraft pulp (NBKP), coniferous kraft pulp (NKP), broadleaf bleached kraft pulp (LBKP), broadleaf kraft pulp (LKP), crushed wood pulp (GP), and thermomechanical. Examples thereof include wood-based pulp such as pulp (TMP), chemithermomechanical pulp (CTMP) and deinked pulp (DIP), and natural pulp such as non-wood pulp such as bast pulp, linter pulp and hemp pulp. These pulps can be used alone or in combination of two or more. Of these, it is preferable to use wood pulp from the viewpoint of quality and cost.

The freeness (Canadian standard freeness, CSF) measured according to JIS P 8121-2012 of the pulp constituting the paper base material 1 is preferably adjusted to 300 to 600 ml. The freshness of the pulp may be adjusted to the above range by beating at least one of the above-mentioned pulps. When two or more types of pulp are used, the pulps beaten separately may be mixed to bring the pulp into the above range, or the pulp mixed in advance may be beaten to adjust to the above range. When the freeness of the pulp is 300 ml or more, there is no possibility that dehydration in the papermaking process will be delayed, and the operability will be improved. Further, when the filtrate degree of the pulp is 600 ml or less, there is no possibility that the paper strength is lowered. The freeness of the pulp is more preferably 300 to 450 ml.

(Multi-layer material)
As the paper base material 1, a multilayer material in which a plurality of paper base materials having different raw materials and characteristics are laminated may be used. Further, the paper base material 1 may be a multilayer material in which pulp layers and starch layers are alternately laminated. When the paper base material 1 is made of a multilayer material, the texture can be made uniform, so that the amount of water vapor permeated from the paper base material 1 at the time of foaming becomes more uniform, overfoaming is suppressed, and the foaming form becomes beautiful. In addition, the starch layer does not excessively increase the barrier property and does not interfere with the permeation of water vapor.

(Starch layer)
In a multilayer material in which a pulp layer and a starch layer are alternately laminated, the starch layer is provided between the pulp layers to firmly bond the pulp layers to each other. As the starch layer, for example, cationized starch, dicarboxylic acid ester starch, urea phosphate esterified starch, etherified starch, acetylated starch, oxidized starch and the like can be used. In this embodiment, it is preferable to contain cationized starch. By doing so, as described above, since the texture can be made uniform, the amount of water vapor permeated from the paper base material at the time of foaming becomes more uniform, overfoaming is suppressed, and the foaming form becomes uniform. In addition, the starch layer using cationized starch does not excessively increase the barrier property and does not further hinder the permeation of water vapor.

The amount of the starch layer formed is preferably 0.5 to 2.0 g / m ² . When the amount of the starch layer formed is 0.5 g / m ² or more, the adhesive force between the pulp layers and the pulp layers is enhanced, and the interlayer strength is improved. Further, when the amount of the starch layer formed is 2.0 g / m ² or less, the starch layer effectively permeates the water vapor from the pulp layer during foaming, and the thermoplastic resin layer 4 can be sufficiently foamed. Therefore, the foaming ratio becomes high and the heat insulating property is improved.

The multilayer material in which the pulp layers and the starch layers are alternately layered can have, for example, two layers, three layers, four layers, six layers or more, and between adjacent pulp layers. A starch layer can be interposed. In the present embodiment, when the paper base material is a multilayer material, it is preferable that the outermost layers on both sides of the multilayer material are pulp layers. In this way, since the pulp layer is arranged on the outside of the multilayer material, the thermoplastic resin layer 4 described later partially penetrates into the pulp layer, and the adhesion between the thermoplastic resin layer 4 and the pulp layer is enhanced. Further, since the pulp layer is arranged on the outside of the multilayer material, problems such as peeling of the starch layer are eliminated, and handleability and productivity are improved.

The starch layer can be formed by applying starch on a wet paper. The method for applying starch is not particularly limited, but it can be obtained, for example, by applying a predetermined amount of an aqueous starch solution with a spray.

(Paper machine)
The paper making method and the type of the paper making machine of the paper base material 1 are not particularly limited, and are a long net paper machine, a twin wire paper machine, a circular net paper machine, a gap former, and a hybrid former (on-top former). A known paper making method and paper machine such as the above can be selected.
The pH at the time of papermaking may be any of an acidic region (acidic papermaking), a pseudo-neutral region (pseudo-neutral papermaking), a neutral region (neutral papermaking), and an alkaline region (alkaline papermaking). After that, an alkaline agent may be applied to the surface of the paper substrate.

(Filling fee)
The filler to be blended when the paper base material 1 is made into paper can be a filler generally used in the papermaking field, and is not particularly limited. Examples of fillers are clay, calcined kaolin, delaminated kaolin, heavy calcium carbonate, light calcium carbonate, light calcium carbonate-silica composite, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous. Examples thereof include inorganic fillers such as silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide and zinc hydroxide, and organic fillers such as urea-formalin resin, polystyrene resin, phenol resin and fine hollow particles. These fillers can be used alone or in combination of two or more. In the case of the above-mentioned acidic papermaking, generally, those obtained by removing acid-soluble ones from these fillers are used.

When papermaking the paper base material 1, it is possible that no filler is added. When the filler of the paper base material 1 is not blended, the foamability is improved when the thermoplastic resin layer 4 is foamed by the moisture contained in the paper base material 1. On the other hand, when the filler is added to the paper base material 1, the opacity of the obtained heat insulating paper container sheet 5 and the foamed heat insulating paper container 8 using the same is improved.

(Internal aid)
When papermaking the paper substrate 1, various internal aids can be appropriately selected and used as needed. Examples of internal additives include various internal sizing agents such as rosin, alkyl ketene dimer (AKD), and alkenyl oxalic acid anhydride (ASA), various nonionic, cationic, and amphoteric yield improvers, and filtrates. Degree improver, paper strength improver, various starches such as cationized starch, polyacrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide, polyamine resin, polyamine, polyethyleneimine, vegetable gum, polyvinyl alcohol, latex , Polyethylene oxide, hydrophilic crosslinked polymer particle dispersions and derivatives or modified products thereof, in sulfuric acid bands, aluminum chloride, sodium aluminate, basic aluminum chloride, basic aluminum compounds such as basic polyaluminum hydroxide, and water. Water-soluble aluminum compounds such as easily decomposable alumina sol, polyvalent metal compounds such as ferrous sulfate and ferric sulfate, silica sol, antifoaming agents, coloring dyes, coloring pigments, fluorescent whitening agents, pH adjusters, pitches Examples include a control agent and a slime control agent.

The basis weight of the paper base material 1 is not particularly limited, but can be, for example, 30 to 400 g / m ² .

(Air permeation resistance)
The air permeation resistance (air permeation resistance / basis weight) per basis weight of the foamed heat insulating paper container paper base material 3 is preferably 1.5 to 6.0 s / g / m ² . When the air permeation resistance per basis weight is in this range, the permeation amount of water vapor is appropriately suppressed in the obtained foam insulation paper container sheet 5 and the foam insulation paper container 8 using the same, and the thermoplastic resin. Since the foamed state of the layer 4 becomes uniform, the balance between the heat insulating property and the beauty is good. The air permeation resistance per basis weight is more preferably 2.0 to 5.5 s / g / m ² , still more preferably 2.7 to 5.0 s / g / m ² , and particularly preferably 3.0 to 4. It is .5 s / g / m ² . The air permeation resistance is measured according to the Oken type testing machine method described in JIS P 8117; 2009.

(Oken type smoothness)
The Oken-type smoothness of the foamed heat insulating paper container paper base material 3 is preferably 30 to 500 seconds. Oken-type smoothness is a unit that is an index for defining the smoothness of the surface of paper. When the Oken type smoothness is 30 seconds or more, the surface property of the paper base material is enhanced, and the foam-insulated paper container sheet 5 having a good surface quality can be obtained. Further, when the Oken type smoothness is 500 seconds or less, the paper base material is crushed with a calender or the like in order to obtain high smoothness, so that the thickness of the paper base material is suppressed from becoming too thin, and the foamed heat insulating paper is prevented. The molding processability of the container 8 is improved.
Oken-type smoothness is measured according to JIS P 8155: 2010.

(Formation index)
The texture index of the foamed heat insulating paper container paper base material 3 is preferably 60 or more, more preferably 80 or more, and further preferably 85 or more. The texture index is an index showing the uniformity of paper (uniformity of microscopic basis weight, smoothness), and the larger the value, the better the texture. By setting the texture index to a predetermined value or more, the water content distribution in the paper substrate becomes uniform. Therefore, the amount of water vapor permeated from the paper base material during foaming becomes more uniform, hyperfoaming is suppressed, and the foaming form becomes uniform. The texture index is obtained by measuring the permeation strength of a paper substrate with a commercially available 3D sheet analyzer and quantifying the variation in thickness. As the 3D sheet analyzer, for example, one manufactured by M / K System Co., Ltd. can be used.

(amount of water)
The water content of the foamed heat insulating paper container paper base material 3 is the sum of the water content contained in the paper base material and the water content contained in the water-soluble resin layer. The water content of the paper base material is determined by the basis weight and water content of the paper base material. The water content of the foamed heat insulating paper container paper base material 3 is preferably 15 to 32 g / m ² , and more preferably 20 to 23 g / m ² . The water content is measured according to JIS P 8127; 2010 after humidity control.

(Basis weight)
The basis weight of the foamed heat insulating paper container paper base material 3 is preferably 100 to 400 g / m ² , more preferably 200 to 400 g / m ² , still more preferably 220 to 400 g / m ² , and particularly preferably. Is 260-350 g / m ² . When the basis weight is 100 g / m ² or more, foaming is sufficiently formed due to the water content, and it is difficult to feel the heat when the obtained foamed heat insulating paper container 8 is gripped by hand. Further, when the basis weight is 400 g / m ² or less, the molding processability of the foamed heat insulating paper container 8 tends to be improved.

(density)
The density of the foamed heat insulating paper container paper base material 3 may be appropriately set as desired, and is not particularly limited, but is preferably 0.60 to 0.99 g / cm ³ . As the density of the foamed heat insulating paper container paper base material 3 becomes lower, water vapor easily passes through the paper base material 1 when the thermoplastic resin layer 4 is foamed, and the foamability tends to be improved. When the density of the foam-insulated paper container paper base material 3 is 0.60 g / cm ³ or more, the paper strength required for the foam-insulated paper container 8 can be easily obtained. Further, when the density of the foamed heat insulating paper container paper base material 3 is 0.99 g / cm ³ or less, water vapor easily passes through the paper base material when the thermoplastic resin layer 4 is foamed, and the foamability tends to be improved. There is.

[Sheet for foam insulation paper container]
As described above, the foam-insulated paper container sheet 5 according to the present embodiment has the thermoplastic resin layer 4 on at least one side of the paper base material 1, and is between the paper base material 1 and the thermoplastic resin layer 4. , Has a water-soluble resin layer 2. The foamed heat insulating paper container sheet 5 is formed by providing the thermoplastic resin layer 4 on the surface of the foamed heat insulating paper container paper base material 3 on which the water-soluble resin layer 2 is formed. Further, by heat-treating the foamed heat insulating paper container sheet 5, the water contained in the paper base material 1 and the water-soluble resin layer 2 is heated and evaporated, and the generated water vapor causes the thermoplastic resin layer 4 to become the foamed resin layer 9. Become. Hereinafter, the foam insulating paper container sheet 5 will be described, but the components already described will be omitted.

(Thermoplastic resin layer)
The thermoplastic resin used for the thermoplastic resin layer 4 is not particularly limited as long as it can be formed on the water-soluble resin layer 2 and can be foamed, and is either a crystalline resin or a non-crystalline resin. Thermoplastic resins can also be used.

Examples of the crystalline resin include polyolefin resins such as polyethylene, polypropylene and polymethylpentene, polyester resins, polyamide resins, polyacetal resins, polyphenylene sulfide (PPS) resins and the like.
Examples of non-crystalline resins include polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene (ABS) resin, acrylic resin, modified polyphenylene ether (PPE), polycarbonate, polyurethane, polyvinyl acetate, and non-crystalline polyethylene terephthalate (PET). ) Etc. can be mentioned.
As these thermoplastic resins, a single resin may be used in a single layer, a plurality of resins may be mixed and used, or a plurality of resins may be used.

Among the above-mentioned thermoplastic resins, polyethylene is preferable because it is excellent in extruded laminate property and foamability. Polyethylene is broadly linear low-density polyethylene (density: 910 to 930 kg / m ³ , melting point: 102 ° C to 122 ° C), low density polyethylene (density: 910 to 930 kg / m ³ , melting point: 102 ° C to 122 ° C). ), Medium-density polyethylene (density: 930 to 942 kg / m ³ , melting point: 110-133 ° C.), high-density polyethylene (density: 942 to 970 kg / m ³ , melting point: 127 to 135 ° C.). Among these, low-density polyethylene is preferable because it is particularly excellent in extruded laminate property and foamability.

The thickness of the thermoplastic resin layer 4 is not particularly limited as long as a foamed heat insulating paper container 8 having desired heat insulating properties can be obtained, but from the viewpoint of heat insulating properties and workability, the thickness before foaming is 30 to 80 μm. It is preferable to have.

(High melting point thermoplastic resin layer, metal layer)
The foam-insulated paper container sheet 5 according to the present embodiment has a high melting point thermoplasticity having a higher melting point than the thermoplastic resin layer 4 on the surface of the paper base material 1 opposite to the surface on which the thermoplastic resin layer 4 is formed. A metal layer such as a resin layer 10 or an aluminum foil may be laminated. Having such a high melting point thermoplastic resin layer 10 or a metal layer, when the foamed heat insulating paper container sheet 5 is heated to foam the thermoplastic resin layer 4, the thermoplastic resin layer 4 of the paper base material 1 is formed. Evaporation of water vapor from the surface opposite to the formed surface is suppressed, and the foamability of the thermoplastic resin layer 4 is improved.

At this time, the melting point of the thermoplastic resin used for the high melting point thermoplastic resin layer 10 does not melt at the heating temperature when the water contained in the paper base material 1 is heated and evaporated, and the diffusion of water vapor can be prevented. Although not particularly limited, it is preferably 125 ° C. or higher. Further, in order to form a metal layer on the surface of the paper base material 1, a metal foil may be laminated, or the metal layer may be formed by a vapor phase method such as a thin film deposition method.

Further, when the high melting point thermoplastic resin layer 10 or the metal layer is present on the inner wall surface side of at least one of the body member 6 and the bottom plate member 7 of the foamed heat insulating paper container 8, the liquid or the like filled in the container enters the paper base material 1. It is preferable because it can suppress the penetration.

Further, the refractory thermoplastic resin layer 10 may be laminated on the thermoplastic resin layer 4 of the foam insulating paper container sheet 5. When the high melting point thermoplastic resin layer 10 is laminated on the thermoplastic resin layer 4, when the foam insulating paper container sheet 5 is heated to foam the thermoplastic resin layer 4, it penetrates the thermoplastic resin layer 4. Since the evaporation of water vapor is suppressed, the foaming property is improved.

When the thermoplastic resin layer 4 is present on the outer wall surface side of the body member 6 of the foamed heat insulating paper container 8, the surface thereof is generally not smooth because unevenness due to foaming occurs. By laminating the high melting point thermoplastic resin layer 10 on the thermoplastic resin layer 4, the surface of the body of the foamed heat insulating paper container 8 can be smoothed, so that a foamed heat insulating paper container 8 having particularly excellent beauty can be obtained. be able to.

The thermoplastic resin used for the high melting point thermoplastic resin layer 10 may be of the same type as the thermoplastic resin used for the thermoplastic resin layer 4, or may be of a different type. For example, when polyethylene is selected for both the thermoplastic resin used for the thermoplastic resin layer 4 and the thermoplastic resin used for the high melting point thermoplastic resin layer 10, the thermoplastic resin layer 4 uses low density polyethylene for high melting point heat. By selecting medium density polyethylene or high density polyethylene for the plastic resin layer 10, it is possible to make the melting point of the high melting point thermoplastic resin layer 10 higher than that of the thermoplastic resin layer 4.

The difference in melting point between the thermoplastic resin layer 4 and the high melting point thermoplastic resin layer 10, that is, the difference in melting point between the thermoplastic resin used for the thermoplastic resin layer 4 and the melting point of the thermoplastic resin used for the high melting point thermoplastic resin layer 10 It is preferably 5 ° C. or higher. When a plurality of types of resins are laminated and used in the thermoplastic resin layer 4 or the high melting point thermoplastic resin layer 10, the resin having the highest melting point among the resins used in the thermoplastic resin layer 4 and the high melting point heat Among the resins used for the thermoplastic resin layer 10, the resin having the lowest melting point preferably has a melting point difference of 5 ° C. or more.

The thickness of the high melting point thermoplastic resin layer 10 suppresses the evaporation of water vapor from the surface opposite to the surface on which the thermoplastic resin layer 4 of the paper substrate 1 is laminated, or penetrates the thermoplastic resin layer 4. It suffices if the vaporization of water vapor can be suppressed, and the amount is not particularly limited, but is about 20 to 50 μm. In particular, when the high melting point thermoplastic resin layer 10 is present on the inner wall surface side of at least one of the body member 6 and the bottom plate member 7 of the foamed heat insulating paper container 8, the thickness of the high melting point thermoplastic resin layer 10 is 20 μm or more. It is possible to effectively prevent the liquid or the like filled in the container from permeating into the paper base material 1.

[Manufacturing method of foam insulation paper container sheet]
The method for producing the foam-insulated paper container sheet 5 is to coat at least one side of the paper base material 1 with a water-soluble resin using a blade coater or a rod coater to form a water-soluble resin layer 2. It has a base material forming step and a foam insulating paper container sheet forming step of forming a thermoplastic resin layer 4 on the water-soluble resin layer 2.
The step of forming the foamed heat insulating paper container paper base material is as described above as the method for producing the foamed heat insulating paper container paper base material 3. Hereinafter, the step of forming the sheet for the foamed heat insulating paper container will be described.

(Sheet forming process for foam insulation paper container)
In the step of forming the foam-insulated paper container sheet 5, the thermoplastic resin layer 4 is formed on the water-soluble resin layer 2 of the paper base material 1. The method for forming the thermoplastic resin layer 4 is not particularly limited, and various methods such as an extrusion laminating method, a wet laminating method, and a dry laminating method may be appropriately used for laminating. In the extrusion laminating method, a thermoplastic resin is extruded from a T-die in the form of a molten resin film on the surface of the water-soluble resin layer 2 of the paper substrate 1, and while cooling between the cooling roll and the nip roll facing the cooling roll. This is a method of pressing and crimping. The extrusion laminating method is preferable because the adhesion between the water-soluble resin layer 2 and the thermoplastic resin layer 4 and the foamability of the thermoplastic resin layer 4 are improved. The same applies to the method for forming the high melting point thermoplastic resin layer 10.

The operating conditions of the extrusion laminating method, that is, the melting temperature of the thermoplastic resin, the laminating speed, and the like may be appropriately set depending on the type and apparatus of the thermoplastic resin to be used, and are not particularly limited. Generally, the melting temperature is about 200 to 370 ° C., and the laminating speed is about 30 to 200 m / min.

[Manufacturing method of foam insulation paper container]
The method for manufacturing the foamed heat insulating paper container 8 includes a foamed heat insulating paper container paper base material forming step, a foamed heat insulating paper container sheet forming step, a paper container molding step, and a foamed heat insulating paper container forming step.
The foam insulating paper container paper base material forming step and the foam insulating paper container sheet forming step are as described above. Hereinafter, the paper container molding process and the foamed heat insulating paper container forming process will be described.

(Paper container molding process)
In the paper container molding step, the paper container is molded using the foam-insulated paper container sheet 5. The method for molding the paper container using the foamed heat insulating paper container sheet 5 is not particularly limited, and the paper container can be produced by a known method. As a specific example, there is a method of molding by a general cup molding machine described below.

First, the foam insulating paper container sheet 5 is printed with necessary printing on the body member blanks such as various patterns and barcodes, and then the body member blanks are punched into a predetermined shape. Positioning of the printed portion can be performed by a conventional method.

Next, a bottom plate member blank is prepared separately from the body member blank. The bottom plate member blank can be manufactured by punching out the foam insulating paper container sheet 5 in the same manner as the body member blank. Further, in order to prevent the liquid or the like filled in the container from permeating into the paper base material 1, the bottom plate member blank may have a structure different from that of the foam insulating paper container sheet 5 of the present embodiment. As the sheet used for the bottom plate member blank, for example, a sheet in which a thermoplastic resin is laminated on a paper base material 1 or a sheet coated with aluminum foil or the like can be used.

The thermoplastic resin used for the bottom plate member blank may be the same type of resin as the thermoplastic resin used for the body member blank, or may be a different resin. If the same type of resin is used as the thermoplastic resin for both, or if both are manufactured from the same foamed heat insulating paper container sheet 5 and used, the body member 6 and the bottom plate member 7 foam at the same time, so that the foamed heat insulating paper container The heat insulating property of 8 becomes even better. In particular, when the foamed heat insulating paper container 8 is used outdoors, in winter, or in a cold region, or when the foamed heat insulating paper container 8 is used for a cup noodle or the like that is left for a while after injecting hot water, the foamed heat insulating paper having the above configuration is used. Container 8 is valid.

Next, the body member blank and the bottom plate member blank are assembled into a container shape by a cup molding machine. When the body member blank and the bottom plate member blank are assembled into a container shape by a cup forming machine, the thermoplastic resin layer 4 may be present on either the outside or the inside of the body member 6 or both, which is desired. It may be appropriately determined according to the heat insulating property, the beauty, the texture, and the like.

(Foam insulation paper container forming process)
In the foam insulation paper container forming step, the paper container is heat-treated to form the foam insulation paper container 8. In this step, the body member blank and the bottom plate member blank are assembled into a container shape, and then heat treatment is performed. When the heat treatment is performed, the water contained in the paper base material 1 or the like of the body member blank or the bottom plate member blank is vaporized, and the thermoplastic resin layer 4 is foamed by the generated water vapor to form the foamed heat insulating paper container 8. The foamed heat insulating paper container 8 uses foamed heat insulating paper 20 for at least one of the body member 6 and the bottom plate member 7, and the foamed heat insulating paper 20 has a foamed resin layer made of a thermoplastic resin on at least one side of the paper base material 1. Has 9.

The conditions for the heat treatment (heating temperature, heating time) may be appropriately set according to the type of the paper base material 1 and the thermoplastic resin, and are not particularly limited. The heating temperature is preferably a temperature slightly higher than the melting point of the thermoplastic resin (melting point + 5 ° C. to melting point + 10 ° C.), and more preferably a temperature lower than the melting point of the thermoplastic resin used for the high melting point thermoplastic resin layer 10. Generally, the heating temperature is about 100 to 200 ° C., and the heating time is about 1 to 6 minutes.

Any means such as hot air, electric heat, and electron beam can be used for the heat treatment. The foamed heat insulating paper container 8 can be manufactured at low cost and with high productivity by continuously heat-treating in a tunnel provided with a transport means by a conveyor.

The thickness of the foamed resin layer 9 foamed in this way is not particularly limited, but can be, for example, 800 to 1500 μm. When the thickness of the foamed resin layer 9 is 800 μm or more, sufficient heat insulating properties can be obtained. Further, when the thickness of the foamed resin layer 9 is 1500 μm or less, the surface is less likely to be uneven due to overfoaming, and the beauty is not impaired.

In the foamed heat insulating paper container 8 according to the present embodiment, if necessary, a technique known in the field of paper containers can be applied as long as the desired effect is not impaired. For example, a technique of applying a paint containing 5 to 40% by mass of a synthetic resin component to a part of the outside of the body member 6 to partially suppress foaming (Patent No. 3014629), that is, the outside of the body member 6, that is, , A technique of applying a tuning ink that synchronizes with foaming to form a smooth printing surface on the outer wall surface of the foamed heat insulating paper container 8 (Patent No. 3408156), forcibly processing the upper edge of the opening of the body member 6 into a square cross section. Examples thereof include, but are not limited to, a technique (Japanese Patent Laid-Open No. 2001-354226) in which the upper flange portion is provided and the inner winding end thereof is polymerized on the upper portion of the flange portion to form a double structure. Further, in order to enhance the beauty, an ink receiving layer containing a pigment and a binder as main components may be provided on the outermost surface layer of the body member 6 which is the outer wall surface of the foamed heat insulating paper container 8.

As the lid material used for the foamed heat insulating paper container 8, a punched sheet 5 for the foamed heat insulating paper container can be used as in the case of the bottom plate member blank. Further, in order to prevent the liquid or the like filled in the container from permeating into the paper base material 1, the lid material may have a structure different from that of the foam insulating paper container sheet 5 according to the present embodiment. As the sheet used for the lid material, for example, a sheet in which a thermoplastic resin is laminated on a paper base material 1 or a sheet coated with aluminum foil or the like can be used.

The foamed heat insulating paper container 8 according to the present embodiment is a foamed heat insulating paper container for filling hot coffee or the like used in a vending machine or the like, a foamed heat insulating paper container for instant foods into which boiling water is injected, and a microwave oven for cooking. Can be used as a container, etc.

Hereinafter, the effects of the present invention will be described in detail with reference to Examples.
The freshness of the pulp was measured according to JIS P 8121: 2012.
The basis weight of the foamed heat insulating paper container paper base material was measured according to JIS P 8124: 2011.
The density of the foamed heat insulating paper container paper base material was measured according to JIS P 8118: 1998.
The Oken-type smoothness of the foamed heat insulating paper container paper base material was measured according to JIS P 8155: 2010.
The texture index of the foam-insulated paper container paper base material is obtained by measuring the permeation strength of the paper base material with a 3D sheet analyzer (manufactured by M / K System Co., Ltd.) and quantifying the variation in thickness. The higher the formation index, the more preferable.
The water content of the foamed heat insulating paper container paper base material was measured according to JIS P 8127: 2010.
The air permeability resistance per basis weight of the foamed heat insulating paper container paper base material was measured according to the Oken type testing machine method described in JIS P 8117: 2009.

[Example 1]
(Effervescent heat insulating paper container paper base material)
Using broad-leaved bleached kraft pulp LBKP (freezing degree 430 ml) as the pulp, cationized starch 0.5% by mass and polyacrylamide-based paper strength enhancer (PAM-based paper strength) with respect to 100% by mass of pulp raw material in terms of solid content. A paper material slurry to which 0.1% by mass of an enhancer), 0.30% by mass of an alkyl keten dimer-based sizing agent, and 0.1% by mass of a polyamide polyamine epichlorohydrin-based resin (PAE-based wet paper strength enhancer) is added. Paper was made by machine. Using five pulp layers obtained by papermaking, cationized starch was applied between each layer at a coating rate of 1.0 g / m ² to obtain a paper base material (base paper) having five pulp layers. ..

Next, intermediate saponification type polyvinyl alcohol (PVA) (manufactured by Japan Vam & Poval Co., Ltd., product name: JM17, saponification degree 96.5 mol%) was applied to both sides (outermost layers on both sides) of the obtained paper substrate by a blade coater. ) Was coated and dried so as to have a solid content of 0.08 g / m ² per side (0.16 g / m ^{2 on} both sides) to obtain a foam-insulated paper container paper base material of Example 1. The penetration thickness of PVA into the paper substrate was 18.5 μm.
The foamed heat insulating paper container paper base material of Example 1 has a basis weight of 300 g / m ² , a density of 0.87 g / cm ³ , a Wangken-type smoothness of 87 seconds, a texture index of 92, a water content of 21.0 g / m ² , and a tsubo. The air permeation resistance per amount was 3.74 s / g / m ² .

(Sheet for foam insulation paper container)
A thermoplastic resin having a high melting point (medium density polyethylene, density 940 kg / m ³ , melting point 133 ° C.) is melted at a melting temperature of 360 ° C. and a laminating speed on one surface of the foamed heat insulating paper container paper base material so as to have a thickness of 40 μm. Extruded at 50 m / min. Then, using a cooling roll and a nip roll (JIS-A hardness: 70), pressure and pressure were applied at a linear pressure of 2 kgf / cm to form a high melting point thermoplastic resin layer.

Next, a thermoplastic resin (low density polyethylene, density 918 kg / m ³ , melting point 103 ° C.) was applied to the other surface of the foamed heat insulating paper container paper base material so as to have a thickness of 50 μm, at a melting temperature of 360 ° C. and a laminating speed of 50 m / m. Extruded in minutes. Then, using a cooling roll and a nip roll (JIS-A hardness: 70), the sheets are pressed and crimped at a linear pressure of 2 kgf / cm to form a thermoplastic resin layer to obtain the foam insulating paper container sheet of Example 1. It was.

[Example 2]
Instead of the PVA of Example 1, a completely saponified polyvinyl alcohol (PVA) (manufactured by Japan Vam & Poval Co., Ltd., product name: JF17, saponification degree 98.5 mol%) was used, and the foamed heat insulating paper container paper base material was used. The penetration thickness of PVA into the paper substrate was 18.5 μm. Other than that, it is the same as in Example 1.
The foamed heat insulating paper container paper base material of Example 2 has a basis weight of 300 g / m ² , a density of 0.88 g / cm ³ , a Wangken-type smoothness of 85 seconds, a texture index of 91, a water content of 21.8 g / m ² , and a tsubo. The air permeability resistance per amount was 3.81 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain a sheet for a foam insulating paper container of Example 2.

[Example 3]
Instead of PVA of Example 1, oxidized starch (manufactured by Oji Constarch Co., Ltd., product name; Ace A) was used, and the solid content per side of the starch was 1.0 g / m ² (2.0 g / m ^{2 on} both sides). It was coated and dried. In the foam-insulated paper container paper base material, the permeation thickness of starch into the paper base material was 50 μm. Other than that, it is the same as in Example 1.
The foamed heat insulating paper container paper base material of Example 3 has a basis weight of 300 g / m ² , a density of 0.87 g / cm ³ , a Wangken-type smoothness of 85 seconds, a texture index of 92, a water content of 20.9 g / m ² , and a tsubo. The air permeability resistance per amount was 2.43 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain a sheet for a foam insulating paper container of Example 3.

[Example 4]
In the foamed heat insulating paper container paper base material of Example 4, PVA was applied by a blade coater. The penetration thickness of PVA into the paper substrate was 15 μm. Other than that, it is the same as in Example 1. Compared to Example 1, in Example 4, the type and amount of the water-soluble resin layer formed are the same, but the penetration thickness of the water-soluble resin into the paper substrate is different. The reason why the permeation thickness of the water-soluble resin into the paper substrate is different is that the pressure of the blade, the gap between the blade and the paper, the angle of the blade, the viscosity of the coating liquid, etc. are different (implementation described later). The same applies to Examples 5 to 7).
The foamed heat insulating paper container paper base material of Example 4 has a basis weight of 300 g / m ² , a density of 0.89 g / cm ³ , a Wangken-type smoothness of 89 seconds, a texture index of 92, a water content of 20.5 g / m ² , and a tsubo. The air permeability resistance per amount was 4.03 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain the foam insulating paper container sheet of Example 4.

[Example 5]
In the foamed heat insulating paper container paper base material of Example 5, PVA was applied by a blade coater. The penetration thickness of PVA into the paper substrate was 25 μm. Other than that, it is the same as in Example 1.
The foamed heat insulating paper container paper base material of Example 5 has a basis weight of 300 g / m ² , a density of 0.87 g / cm ³ , a Wangken-type smoothness of 81 seconds, a texture index of 92, a water content of 20.8 g / m ² , and a tsubo. The air permeation resistance per amount was 3.01 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain the foam insulating paper container sheet of Example 5.

[Example 6]
In the foamed heat insulating paper container paper base material of Example 6, PVA was applied by a blade coater. The penetration thickness of PVA into the paper substrate was 5 μm. Other than that, it is the same as in Example 1.
The foamed heat insulating paper container paper base material of Example 6 has a basis weight of 300 g / m ² , a density of 0.87 g / cm ³ , a Wangken-type smoothness of 81 seconds, a texture index of 92, a water content of 21.5 g / m ² , and a tsubo. The air permeability resistance per amount was 5.33 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain the foam insulating paper container sheet of Example 6.

[Example 7]
In the foamed heat insulating paper container paper base material of Example 7, PVA was coated and dried with a rod coater so that the solid content per side was 0.08 g / m ² (0.16 g / m ^{2 on} both sides). The penetration thickness of PVA into the paper substrate was 35 μm. Other than that, it is the same as in Example 1.
The foamed heat insulating paper container paper base material of Example 7 has a basis weight of 300 g / m ² , a density of 0.87 g / cm ³ , a Wangken-type smoothness of 81 seconds, a texture index of 92, a water content of 21.1 g / m ² , and a tsubo. The air permeation resistance per amount was 2.51 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain the foam insulating paper container sheet of Example 7.

[Comparative Example 1]
In the foamed heat insulating paper container paper base material of Comparative Example 1, PVA was applied by a blade coater. The penetration thickness of PVA into the paper substrate was 3 μm. Other than that, it is the same as in Example 1.
The foamed heat insulating paper container paper base material of Comparative Example 1 has a basis weight of 300 g / m ² , a density of 0.89 g / cm ³ , a Wangken-type smoothness of 103 seconds, a formation index of 80, a water content of 21.0 g / m ² , and a tsubo. The air permeability resistance per amount was 6.32 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain a sheet for a foam insulating paper container of Comparative Example 1.

[Comparative Example 2]
In the foamed heat insulating paper container paper base material of Comparative Example 2, PVA coating (coater) was performed by a 2-roll size press. The penetration thickness of PVA into the paper substrate was 40 μm. Other than that, it is the same as in Example 1.
The foam-insulated paper container paper base material of Comparative Example 2 has a basis weight of 300 g / m ² , a density of 0.88 g / cm ³ , a Wangken-type smoothness of 88 seconds, a texture index of 90, a water content of 20.3 g / m ² , and a tsubo. The air permeability resistance per amount was 1.32 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain the foam insulating paper container sheet of Comparative Example 2.

[Comparative Example 3]
In the foamed heat insulating paper container paper base material of Comparative Example 3, PVA was coated (coater) with a blade coater, and PVA was 0.03 g / m ² per side (0.06 g / m ^{2 on} both sides). It was coated and dried. The penetration thickness of PVA into the paper substrate was 15 μm. Other than that, it is the same as in Example 1.
The foam-insulated paper container paper base material of Comparative Example 3 has a basis weight of 300 g / m ² , a density of 0.88 g / cm ³ , a Wangken-type smoothness of 88 seconds, a texture index of 90, a water content of 22.5 g / m ² , and a tsubo. The air permeability resistance per amount was 1.28 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain the foam insulating paper container sheet of Comparative Example 3.

[Comparative Example 4]
In the foamed heat insulating paper container paper base material of Comparative Example 4, PVA was applied by a calendar size press, and PVA was applied in a solid content of 0.3 g / m ² per side (0.6 g / m ^{2 on} both sides). It was coated and dried so that it became. The penetration thickness of PVA into the paper substrate was 60 μm. Other than that, it is the same as in Example 1.
The foam-insulated paper container paper base material of Comparative Example 3 has a basis weight of 300 g / m ² , a density of 0.89 g / cm ³ , a Wangken-type smoothness of 110 seconds, a texture index of 72, a water content of 22.1 g / m ² , and a tsubo. The air permeability resistance per amount was 1.31 s / g / m ² .
Then, the high melting point thermoplastic resin layer and the thermoplastic resin layer were formed in the same manner as in Example 1 to obtain the foam insulating paper container sheet of Comparative Example 4.

The foam-insulated paper container sheet obtained as described above was evaluated as follows. The evaluation results are as shown in Table 1.

(Thermal insulation properties)
An A4 size sample was cut out from the obtained foam insulation paper container sheet. A cylinder was made with the thermoplastic resin layer on the outside. Then, using hot air, the thermoplastic resin layer on the outside of the cylinder was foamed at a heating temperature of 120 ° C. and a heating time of 6 minutes.
The foaming ratio was calculated from the thickness of the obtained foamed heat insulating paper before and after foaming, and evaluated according to the following criteria. Note that ⊚, ○, and △ are acceptable, and × is rejected.
⊚: The foaming ratio is 21 times or more, and the heat insulating property is sufficient.
◯: The foaming ratio is 19 times or more and less than 21 times, and the heat insulating property is sufficient.
Δ: The foaming ratio is 15 times or more and less than 19 times, and has heat insulating properties.
X: The foaming ratio is less than 15 times, and the heat insulating property is insufficient.

(Beauty)
From the obtained foam insulating paper container sheet, a square test piece having a side of 100 mm was cut out. Then, using hot air, the thermoplastic resin layer was foamed at a heating temperature of 120 ° C. and a heating time of 6 minutes. The surface of the thermoplastic resin layer after foaming was visually observed, and the beauty was evaluated according to the following criteria. Note that ⊚, ○, and △ are acceptable, and × is rejected.
⊚: No hyperfoaming was observed, the formed foam cells were small and homogeneous, and the surface was generally flat.
◯: No hyperfoaming was observed, and the formed foam cells were small and the surface was generally flat, but the size of the foam cells varied.
Δ: The formed foam cells are slightly large and the size varies, but the surface irregularities are small and no hyperfoaming is observed.
X: There are large irregularities on the surface such as overfoaming.

As can be seen from Table 1, the foam-insulated paper container sheets of Examples 1 to 7 were excellent in both heat insulating properties and aesthetic performance. It was found that when the permeation thickness of the water-soluble resin (PVA) into the paper substrate was 15 to 25 μm, the heat insulating property and the beauty were particularly excellent.
In the foamed heat insulating paper container sheet of Comparative Example 1, the permeation thickness of the water-soluble resin (PVA) into the paper base material was too small, so that the foamed resin layer after foaming could not be sufficiently foamed, and the foamed resin layer had heat insulating properties. Was inferior.
The foam-insulated paper container sheet of Comparative Example 2 was coated with a water-soluble resin using a two-roll size press. In Comparative Example 2, the amount of water vapor permeated greatly varied depending on the location, and hyperfoaming occurred, resulting in large irregularities on the surface. Therefore, the foam-insulated paper container sheet of Comparative Example 2 was inferior in surface beauty.
In the foamed heat insulating paper container sheet of Comparative Example 3, since the amount of water-soluble resin (PVA) formed was too small, uniform foaming could not be obtained, and large irregularities were generated on the surface. Therefore, the foam-insulated paper container sheet of Comparative Example 3 was inferior in surface beauty.
The foam-insulated paper container sheet of Comparative Example 4 was coated with a water-soluble resin using a calendar-sized press. In Comparative Example 4, the permeation thickness of the water-soluble resin (PVA) into the paper substrate was relatively large, the amount of water vapor permeated greatly varied depending on the location, and hyperfoaming occurred to cause large irregularities on the surface. .. Therefore, the foam-insulated paper container sheet of Comparative Example 4 was inferior in surface beauty.

1 Paper base material 2 Water-soluble resin layer 3 Foam insulation paper container Paper base material 4 Thermoplastic resin layer 5 Foam insulation paper container sheet 6 Body member 7 Bottom plate member 8 Foam insulation paper container 9 Foam resin layer 10 High melting point thermoplastic resin Layer 20 foam insulation paper

Claims (6)

A method for producing a foam-insulated paper container paper base material, which forms a water-soluble resin layer by coating at least one side of a paper base material with a water-soluble resin using a blade coater or a rod coater.
The amount of the water-soluble resin layer formed per side is 0.05 to 6.0 g / m ² .
A method for producing a foam-insulated paper container paper base material, wherein the permeation thickness of the water-soluble resin into the paper base material is 5 to 50 μm. The method for producing a foamed heat insulating paper container paper base material according to claim 1, wherein the water-soluble resin contains at least one selected from polyvinyl alcohol, starches and polyacrylamides. The method for producing a foamed heat insulating paper container paper base material according to claim 1 or ² , wherein the air permeation resistance per basis weight is 1.5 to 6.0 s / g / m ² . A method for producing a sheet for a foam-insulated paper container having a thermoplastic resin layer on at least one side of a paper base material.
A foam insulating paper container paper base material forming step of coating a water-soluble resin on at least one side of the paper base material using a blade coater or a rod coater to form a water-soluble resin layer.
It has a foam insulating paper container sheet forming step of forming the thermoplastic resin layer on the water-soluble resin layer.
The amount of the water-soluble resin layer formed per side is 0.05 to 6.0 g / m ² .
A method for producing a sheet for a foam-insulated paper container, characterized in that the permeation thickness of the water-soluble resin into the paper substrate is 5 to 50 μm. A method for manufacturing a foamed heat insulating paper container using foamed heat insulating paper for at least one of a body member and a bottom plate member.
A foam insulating paper container paper base material forming step of coating a water-soluble resin on at least one side of a paper base material using a blade coater or a rod coater to form a water-soluble resin layer.
A step of forming a sheet for a foamed heat insulating paper container for forming a thermoplastic resin layer on the water-soluble resin layer, and
A paper container molding step of molding a paper container using the foamed heat insulating paper container sheet, and
It has a foam insulating paper container forming step which heat-treats the paper container to form a foam insulating paper container.
The amount of the water-soluble resin layer formed per side is 0.05 to 6.0 g / m ² .
A method for producing a foam-insulated paper container, characterized in that the permeation thickness of the water-soluble resin into the paper substrate is 5 to 50 μm. An effervescent heat insulating paper container paper base material having a water-soluble resin layer containing a water-soluble resin coated by a blade coater or a rod coater on at least one side of the paper base material.
The amount of the water-soluble resin layer formed per side is 0.05 to 6.0 g / m ² .
A foam-insulated paper container paper base material characterized in that the permeation thickness of the water-soluble resin into the paper base material is 5 to 50 μm.

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