JP2020079461A - Foamed heat insulation paper container - Google Patents

Abstract

To provide a foamed heat insulation paper container exhibiting both softness and a low thermal conductivity to prevent heat of the contents from being transferred to the gripping fingers, and having good touching feel.SOLUTION: The foamed heat insulation paper container comprises, from its outside, a foamed resin layer comprising a thermoplastic resin, a barrel member assembled with a paper substrate layer and thermoplastic resin, and a bottom plate member, and has compression recovery of 55-90% and compressive energy of 0.10-0.95 N m/m.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a foam insulation paper container.

  BACKGROUND ART In fast food restaurants, trains, vending machines, and the like, heat insulating containers are widely used as containers for providing hot drinks such as coffee and hot foods such as soup to purchasers. Conventionally, as such a heat insulating container, a foam heat insulating paper container has been known. Foam insulation paper containers use paper as a base material and have a thermoplastic resin layer with a thickness sufficient to achieve heat insulation, so they have a lower environmental impact than print containers made of expanded polystyrene, and have good printability. It also has the advantage of being excellent.

  In order to improve the heat insulating property and workability of a foam insulating paper container, Patent Document 1 discloses that a pulp containing a high concentration beaten pulp at a pulp concentration of 20 to 35% by weight is used, and the surface is treated by a two roll size press coater or a gate roll coater. Disclosed is a method for producing a sheet for a heat insulating paper container, in which a foamed thermoplastic resin layer is laminated on at least one surface of a paper base material to be treated.

In Patent Document 2, Oken type smoothness of the surface treated by a calendar size press is 58 to 120 s/10 ml, and air permeability resistance per grammage is 0.88 to 1.31 s/g/m. There is disclosed a method for producing a sheet for a foam insulating paper container in which a thermoplastic resin layer is laminated on the surface of the paper base material of No. ² .

Japanese Patent No. 5673289 Japanese Patent No. 5903972

According to the inventions of Patent Documents 1 and 2, it is possible to more evenly foam the thermoplastic resin layer of the foam insulating paper container sheet and obtain a foam insulating paper container having high heat insulation properties.
However, in a foam insulating paper container that is generally held by hand and used, not only the heat insulating property but also the touch and the comfort are important. The inventions of Patent Documents 1 and 2 do not have the viewpoint of improving the touch and the comfort.

  The foamed resin layer of the foamed heat-insulating paper container has an appropriate softness, and unless it can be dented by the pressure applied by the grip, it cannot exhibit the good touch peculiar to the foamed resin layer. On the other hand, if the foamed resin layer is too recessed, the temperature of the contents of the foamed heat insulating paper container is directly transmitted to the finger to be gripped, and the foamed heat insulating paper container is difficult to hold.

  Based on the above, it is an object of the present invention to provide a foamed thermal insulation paper container having both softness and the property that it is difficult to transfer the heat of the contents to the fingers to be gripped and having a good touch feeling.

The present inventors diligently studied the characteristics of the foamed thermal insulation paper container having a correlation with the feeling of touch. As a result, it has been found that if the compression energy and the compression recovery property of the foam insulating paper container can be set within a predetermined range, the touch of the foam insulating paper container can be improved.
The present invention has the following configurations.

(1) A foamed heat-insulating paper container comprising a body member having a foamed resin layer made of a thermoplastic resin, a paper base material layer and a thermoplastic resin layer and a bottom plate member in order from the outside, and having a compression recovery property of 55 to 55. 90%, and the compression energy is 0.10 to 0.95 N·m/m ² .

(2) The foam insulation paper container of (1), wherein the outermost layer has a surface roughness of 5 to 75 μm.

(3) The main component of the paper base material constituting the paper base material layer is cellulose pulp, a water-soluble resin layer is provided between the paper base material layer and the foamed resin layer, and the paper base The foam insulation paper container of (1) or (2) above, wherein the air permeation resistance per basis weight of the material is 0.35 to 1.92 s/g/m ² .

(4) The paper base material comprises a monohydric straight chain alcohol having at least one kind of carbon number selected from the group consisting of 24, 26 and 28, and 24, 26 and 28 carbon atoms. The foamed heat-insulating paper container according to (3) above, which contains at least 200 to 2500 ppm in total of at least one linear fatty acid having a carbon number selected from the group.

(5) The foamed heat-insulating paper container according to (3) or (4), wherein the proportion of acacia pulp in the cellulose pulp is 10% by mass or more.

(6) The foam heat-insulating paper container according to any one of (3) to (5), wherein the paper base material is a multi-layer material.

(7) The foamed heat-insulating paper container according to any one of (1) to (6), wherein the resin forming the foamed resin layer is polyethylene.

  The foam insulation paper container according to the present invention has both softness and the property that it is difficult to transfer the heat of the contents to the fingers to be gripped, and has a good feel.

It is a typical sectional view of the foam insulation paper container concerning this embodiment. It is an expanded sectional view of the part shown by A of FIG. It is a typical sectional view of the sheet for foam insulation paper containers concerning this embodiment. It is a typical sectional view of the foaming insulation paper container paper base material concerning this embodiment. It is a typical sectional view of the foam heat insulation paper container paper base material concerning this embodiment, and especially shows the paper base material in detail.

  Hereinafter, embodiments of the present invention will be specifically described. The description of the constituent requirements described below may be made based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, the numerical range represented using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

  FIG. 1 is a schematic cross-sectional view of an example of the foam insulation paper container 8. FIG. 2 is an enlarged cross-sectional view of the portion indicated by A in FIG. As shown in FIG. 2, the foam insulation paper container 8 includes a foam insulation paper container paper base material 3, a foam resin layer 9, and a transpiration suppression layer 10.

FIG. 3 is a schematic cross-sectional view of an example of the foamed insulating paper container sheet 5. The foam insulation sheet container sheet 5 comprises a foam insulation sheet container base material 3 having a water-soluble resin layer 2 on one surface of a paper substrate 1, and a thermoplastic resin layer 4 laminated on the water-soluble resin layer 2. Have The thermoplastic resin layer 4 is foamed by heat treatment to become a foamed resin layer 9.
FIG. 4 is a schematic cross-sectional view of an example of the paper base material 3 of the foam insulation paper container. The foamed thermal insulation paper container paper base material 3 has a water-soluble resin layer 2 on both sides of the paper base material 1. By laminating the thermoplastic resin layer 4 on one of the water-soluble resin layers 2, the foamed heat insulating paper container sheet 5 is formed.

The foam insulation paper container 8 is manufactured by forming the paper container using the foam insulation paper container sheet 5 for the body member 6 and the bottom plate member 7 and heating the paper container.
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, which permeates the water-soluble resin layer 2 and in the heated thermoplastic resin layer 4. And foams the thermoplastic resin to change the thermoplastic resin layer 4 into the foamed resin layer 9. As a result, the paper container becomes a foam insulating paper container 8 having heat insulating properties.

Hereinafter, each member which comprises this embodiment is demonstrated.
[Paper substrate]
(Pulp type)
The paper base material 1 contains cellulose pulp as a main component. Here, the main component means a component accounting for 50% by mass or more of the components constituting the paper base material 1.
Examples of the pulp that can form the paper substrate 1 include bleached kraft pulp of softwood (NBKP), softwood kraft pulp (NKP), bleached kraft pulp of hardwood (LBKP), and hardwood kraft pulp (LKP) as wood-based pulp. ) And other chemical pulps, ground pulp (GP), chemi-ground pulp (CGP), thermomechanical pulp (TMP), chemi-thermo-mechanical pulp (CTMP) and other mechanical pulps, and non-wood pulps such as hemp pulp. Is applicable. These pulps can be used alone or in combination of two or more. From the viewpoint of quality and cost, wood-based pulp such as acacia wood and eucalyptus wood which is LKP, and radiata pine wood which is NKP is suitable as the pulp constituting the paper base material 1.

(Total content of linear alcohol and linear fatty acid)
The paper base material 1 contains a linear alcohol and a linear fatty acid derived from cellulose pulp. Since alcohols and fatty acids are generally synthesized in plants using acetic acid as a starting material, the number of carbon atoms of the synthesized alcohols and fatty acids is even. The linear alcohol and linear fatty acid contained in the paper substrate 1 can be measured by gas chromatography or the like.

  The paper base material 1 is at least one monovalent linear alcohol having a carbon number selected from the group consisting of 24, 26, and 28 carbon atoms (hereinafter sometimes referred to as a linear alcohol (A)). , A linear fatty acid having at least one carbon number selected from the group consisting of 24, 26, and 28 carbon atoms (hereinafter sometimes referred to as linear fatty acid (B)) in a total amount of 200 to 2500 ppm. It is preferable that the content is 350 to 2000 ppm.

  When the total content of the straight-chain alcohol (A) and the straight-chain fatty acid (B) is 200 ppm or more with respect to the mass of the paper base material 1, it is possible to effectively suppress the ejection of water vapor and form a uniform and dense foamed resin layer 9 can be obtained. It is speculated that this inhibitory effect may be exerted by the fact that the linear alcohol (A) and the linear fatty acid (B) are distributed between the fibers to moderate the transpiration rate.

  On the other hand, when the total content of the linear alcohol (A) and the linear fatty acid (B) is 2500 ppm or less with respect to the mass of the paper substrate 1, dust (which appears due to solidification of the linear alcohol and the linear fatty acid) , Black, brown, or transparent spots) can be suppressed.

  When 10% by mass or more of the pulp constituting the paper base material 1 is acacia pulp, the air permeation resistance of the paper base material 1 is controlled within a predetermined range to be described later, and the permeation of water vapor generated from the paper base material 1 is controlled. This is preferable because it becomes easy to make the amount uniform over the entire paper substrate 1. From the viewpoint of making the permeation amount of water vapor generated from the paper base material 1 more uniform, it is more preferable that 17% by mass or more of the pulp constituting the paper base material 1 is acacia pulp. Acacia wood is one of the tree species containing a large amount of the above linear alcohol (A) and linear fatty acid (B).

(Canadian standard freeness)
The freeness (Canadian standard freeness) of the pulp constituting the paper substrate 1 measured according to JIS P 8121:2012 is preferably adjusted to 300 to 600 ml, and more preferably adjusted to 300 to 450 ml. preferable.
When two or more types of pulp are used, the pulps beaten separately may be mixed to the above range, or the pulp mixed beforehand may be beaten to adjust the above range.
When the freeness is 300 ml or more, dehydration in the papermaking process does not take a long time, and the workability is improved. On the other hand, when the freeness is 600 ml or less, the paper strength does not decrease.

(Filler)
The paper base material 1 (or the pulp layer 11 described later) may contain a filler generally used in the papermaking field. For example, inorganic pigments such as calcium sulfite, gypsum, talc, kaolin, delaminated kaolin, silicon hydrate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, or zinc hydroxide, or urea/formalin. Organic fine particles such as resin fine particles or fine hollow particles may be added depending on the purpose. It is also possible to add no filler to the paper base material 1. If the paper base material 1 is not blended with a filler, the foamability is improved when the thermoplastic resin layer 4 is foamed by the water content in the paper base material 1.

(Internal additive)
When the paper substrate 1 (pulp layer 11) is made into paper, various internal addition aids can be appropriately added. Examples of the internal additive aids include sizing agents, retention agents, drainage improvers, bulky materials, paper strength improvers, various starches such as cationized starch, sulfuric acid bands, colored dyes, colored pigments, optical brighteners, Examples thereof include pH adjusters, pitch control agents, slime control agents and the like. The paper base 1 (pulp layer 11) preferably contains cationized starch as an internal addition aid.

(Multilayer material)
The paper base material 1 is preferably a multilayer material in which pulp layers 11 and starch layers 12 are alternately stacked. When the multi-layered material is used as the paper base material 1, the texture of the paper base material 1 can be made uniform, so that the permeation amount of water vapor generated from the paper base material 1 during heating becomes more uniform throughout the paper base material 1, and the thermoplastic resin Over-foaming of the layer 4 is suppressed, and the foaming form of the foamed resin layer 9 becomes more uniform.

(Starch layer)
The starch layer 12 firmly adheres the pulp layers 11 to each other. The starch used in the starch layer 12 is not particularly limited, but cationized starch is preferable.
The amount of the starch layer 12 formed is preferably 0.5 to 2.0 g/m ² . When the amount of the starch layer 12 formed is 0.5 g/m ² or more, the adhesive strength between the pulp layer 11 and the pulp layer 11 can be increased, and the interlayer strength can be improved. When the amount of starch layer 12 formed is 2.0 g/m ² or less, the thermoplastic resin layer 4 is sufficiently foamed without excessively impeding the permeation of water vapor generated from the pulp layer 11 during heating. Since the thick foam resin layer 9 is obtained, the heat insulation of the foam insulation paper container 8 is improved.

  The number of layers of the pulp layer 11 of the multilayer material is not limited to the five layers illustrated in FIG. 5 and can be increased or decreased.

(Papermaking)
As the paper making method of the paper substrate 1 (pulp layer 11) and the type of the paper making machine, known paper making methods and paper making machines such as a Fourdrinier paper machine, a twin wire paper machine, a cylinder paper machine and a gap former can be selected. Is. Of these, a method capable of multi-layer papermaking having a plurality of inlets is preferable. The pH during 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).

(Method of forming starch layer)
The starch layer 12 can be formed by various known methods such as a coating method, a transfer method, an impregnation method, and a spraying method, using a known apparatus. For example, the starch layer 12 can form a uniform starch layer by spraying on the surface of the pulp layer 11 on a wire.

(Air resistance of paper substrate)
As a result of investigations, the present inventors have found that when the air permeation resistance per unit weight of the paper base material 1 is 0.35 to 1.92 s/g/m ² , the water vapor generated from the paper base material 1 permeates. It has been found that the temperature can be controlled within a range in which foaming of the thermoplastic resin is sufficient. When the air permeation resistance per grammage of the paper substrate 1 is 0.35 s/g/m ² or more, the permeation of water vapor is suitably controlled, so that partial overfoaming of the thermoplastic resin layer 4 may occur. It does not occur, and the beauty of the foam insulating paper container 8 is improved. On the other hand, when the air permeation resistance per basis weight of the paper base material 1 is 1.92 s/g/m ² or less, the permeation of water vapor is not excessively hindered, so that the thermoplastic resin layer is sufficiently foamed and foamed. The heat insulating property of the heat insulating paper container 8 is improved.
As described above, when the air permeation resistance per grammage is adjusted within the above range, the permeation of water vapor can be controlled by the paper base material 1, so that the paper base material 1 is not thickly coated with the water-soluble resin layer 2, It is possible to improve the beauty of the foam insulation paper container 8.

Air resistance per basis weight of the paper substrate 1 is preferably set to 0.40s / g / ^{m 2} or more from the viewpoint of obtaining a better aesthetic properties, and 0.45s / g / ^{m 2} or more Is more preferable.
Air resistance per basis weight of the paper substrate 1, from the viewpoint of obtaining a better thermal insulation properties to the 1.85s / g / ^{m 2} or less, and 1.80s / g / ^{m 2} or less Is more preferable.
The air permeation resistance per grammage of the paper base material 1 can be measured for the paper base material 1 before the water-soluble resin layer 2 is applied, or it can also be measured from the foamed insulating paper container paper base material 3 to the water-soluble resin layer 2 It is also possible to measure the paper base material 1 obtained by removing.
The air resistance is measured according to the Oken type tester method of JIS P 8117:2009.

[Water-soluble resin]
The water-soluble resin is a resin that dissolves in water, and is applied as an aqueous solution to the surface of the paper substrate 1 to form a film (water-soluble resin layer 2). The water-soluble resin is not particularly limited as long as it is a water-soluble polymer having film-forming properties, but from the viewpoint of processability, polyvinyl alcohol (PVA), starch, and polyacrylamides are preferable, and PVA is particularly preferable. As the water-soluble resin in the present embodiment, these can be used alone or in combination of two or more kinds.

(Polyvinyl alcohol)
Polyvinyl alcohol (PVA) has the formula _{[-CH 2 CH (OH) -} ] n [-CH 2 CH (OCOCH 3) -] is represented by _m. In the above chemical formula, n represents a saponified portion and m represents an unsaponified portion.
When the average degree of polymerization of PVA is measured according to JIS K 6726:1994, it is preferably 300 to 4000, more preferably 500 to 3000, and even more preferably 1000 to 2000. When the average degree of polymerization is 300 or more, the film-forming property is improved, and when it is 4000 or less, the solubility in water is improved. The average degree of polymerization can be controlled by how much vinyl acetate monomer is bonded in the polymerization of vinyl acetate monomer during the production process of PVA.

In this embodiment, modified PVA or unmodified PVA can be used, and partially saponified PVA or fully saponified PVA (in this embodiment, a saponification degree of 90 mol% or more) can be used. ..
Unmodified PVA refers to PVA in which functional groups other than hydroxyl groups (OH groups) and acetic acid groups (OCOCH ₃ groups) have not been introduced. The modified PVA refers to PVA having a functional group such as a carboxyl group, a carbonyl group or a sulfonic acid group introduced therein.
The degree of saponification (mol%) of PVA is represented by {n/(n+m)}×100, which can be adjusted by the degree of substitution of the acetic acid groups with the hydroxyl groups during saponification of the polyvinyl acetate resin during the PVA production process. Yes, it can be measured according to JIS K 6726:1994. When the saponification degree is 80 mol% or more, the water solubility of PVA is increased and the film forming property is improved, which is preferable.

(Suitable water-soluble resin other than polyvinyl alcohol)
Examples of starches that can be used as the water-soluble resin include unmodified starch, enzyme-modified starch, thermochemically modified starch, oxidized starch, esterified starch, etherified starch (eg, hydroxyethylated starch), cationized starch, and the like. Can be mentioned. Examples of the polyacrylamides (PAM) include polyacrylamide, cationic polyacrylamide, anionic polyacrylamide, amphoteric polyacrylamide, nonionic polyacrylamide and the like.

[Water-soluble resin layer]
The water-soluble resin layer 2 firmly adhered to the paper base 1 can control the amount of water vapor permeation to make the amount of water vapor permeation uniform throughout the paper base 1. As a result, the foamed state of the thermoplastic resin layer 4 can be made uniform, and the heat insulating property of the foam insulating paper container 8 can be improved.
The water-soluble resin layer 2 is a layer containing a water-soluble resin as a main component, but may optionally contain other resin components as long as the effects of the invention are not impaired.

(Method for forming water-soluble resin layer)
As shown in FIG. 4, the foamed thermal insulation paper container paper base material 3 of the present embodiment is manufactured by forming the water-soluble resin layers 2 on both surfaces of the paper base material 1. The water-soluble resin layer 2 may be provided on only one side of the paper base material 1.
The method of forming the water-soluble resin layer 2 is not particularly limited, but from the viewpoint of making the coating amount of the water-soluble resin and the penetration thickness into the paper base material 1 uniform, a water-soluble resin is prepared using a blade coater or a rod coater. Is preferred.

The blade coater is an apparatus that scrapes off the coating liquid supplied to the surface of the paper base material 1 with a steel blade (plate blade) to apply a necessary amount.
The blade coater is a blade having a length that traverses the paper base material 1 and is arranged in close proximity to the paper base material 1 at an angle with respect to the paper base material 1. The blade coater cannot pass through a gap between the paper base material 1 and the blade. The coating liquid is scraped off to apply the coating liquid at high speed and smoothly.
The coating amount can be adjusted by the pressing pressure and angle of the blade.

With a rod coater, the coating liquid supplied to the surface of the paper base material 1 is scraped off using a smooth rod, a rod in which piano wire, stainless steel wire, or the like is closely wound, a rod having many grooves on the surface, or the like. This is a device to apply the required amount.
The rod coater is a rod having a length that traverses the paper base material 1 and is disposed in close proximity to the paper base material 1. The rod coater removes excess coating liquid that cannot pass through the gap between the paper base material 1 and the rod. By scraping off, the coating liquid is applied at high speed and smoothly. The rod coater is also called a bar coater.
The coating amount can be adjusted by changing the diameter of the piano wire or stainless wire wound around the rod.

By using a blade coater or a rod coater, the uniform water-soluble resin layer 2 can be thinly formed on the paper base material 1 even when a high-concentration coating liquid is used.
A high-concentration coating liquid has a high solution viscosity, so that it hardly penetrates into the paper base material 1, reduces the permeation thickness of the water-soluble resin into the paper base material 1, and is water-soluble in the water-soluble resin layer 2. The resin concentration can be increased. Therefore, if a blade coater or a rod coater is used, even if the coating amount of the water-soluble resin is small, the permeation amount of water vapor generated from the paper base material 1 can be effectively controlled.

Water is usually used as the solvent of the coating liquid, and an organic solvent such as alcohol soluble in water may be mixed and used as necessary. The coating liquid may be used in combination with various known auxiliaries such as a surfactant, a defoaming agent, a dye, a pigment, a sizing agent, a water resistance agent, a paper strength enhancer, a dispersant and a plasticizer.
The method for drying the coating layer may be appropriately selected from known methods. Further, after forming the water-soluble resin layer 2, a smoothing treatment can be performed if necessary.

(Amount of water-soluble resin layer formed)
The amount of the water-soluble resin layer 2 formed on one surface is preferably 0.03 to 6.00 g/m ² in terms of solid content. In particular it is preferred that the case of using PVA as the water-soluble resin is a 0.05~0.50g / ^{m 2,} and more preferably 0.06~0.10g / ^{m 2.} Preferably when using the starch is 0.80~6.00g / ^{m 2,} and more preferably 1.50~3.00g / ^{m 2.} Preferably when using the PAM is 0.03~0.70g / ^{m 2,} and more preferably 0.05~0.60g / ^{m 2.}

When the amount of the water-soluble resin layer 2 formed on one surface is equal to or less than the upper limit of the preferable amount of each water-soluble resin formed, the equipment stains in the paper making process or the drying process are reduced, and the stains on the foam insulation paper container 8 are reduced. Can be prevented from being mixed. Further, it is possible to sufficiently transmit the water vapor generated from the paper base material 1, thicken the foamed resin layer, and obtain the foamed heat-insulating paper container 8 having a high heat insulating property.
On the other hand, when the amount of the water-soluble resin layer 2 formed on one side is equal to or more than the lower limit of the preferable amount of each water-soluble resin formed, the amount of water vapor generated from the paper substrate 1 is adjusted to the foamed thermal insulation paper container paper substrate. 3 can be made uniform. By preventing the foaming of the thermoplastic resin layer 4 by making the amount of permeation of water vapor uniform, it is possible to obtain the foamed insulating paper container 8 having a beautiful surface. The formation amount of the water-soluble resin layer 2 represents an average formation amount, and can be confirmed by a weight change before and after drying, an optical microscope, a scanning electron microscope, or the like.

(Thickness of permeation of water-soluble resin into paper substrate)
When a coating liquid containing a water-soluble resin is applied to the surface of the paper base material 1, the coating liquid permeates toward the inside of the paper base material 1. After that, the coating liquid is solidified by drying to form the water-soluble resin layer 2. 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 preferably 5 to 180 μm. Particularly when PVA is used as the water-soluble resin, it is preferably 5 to 35 μm, more preferably 10 to 30 μm, and further preferably 15 to 25 μm. When starch is used, it is preferably 60 to 180 μm, more preferably 65 to 170 μm, and even more preferably 70 to 160 μm. When PAM is used, it is preferably 5 to 70 μm, more preferably 8 to 50 μm, still more preferably 15 to 30 μm.

When the permeation thickness of the water-soluble resin into the paper base material 1 is equal to or more than the lower limit value of the preferable permeation thickness of each water-soluble resin, the permeation amount of water vapor is made uniform, so that the thermoplastic resin layer 4 is formed. Since the foaming is made uniform, the beauty of the foam insulating paper container 8 is improved. On the other hand, when the permeation thickness of the water-soluble resin into the paper base material 1 is equal to or less than the above upper limit of the preferable permeation thickness of each water-soluble resin, the water-soluble resin layer 2 may hinder the permeation of water vapor excessively. However, the thermoplastic resin layer 4 is sufficiently foamed, and the heat insulating property of the foam insulating paper container 8 is improved.
The permeation thickness of the water-soluble resin into the paper substrate 1 can be adjusted by the pressure of the blade or the like, the angle, the size of the gap between the blade or the like and the paper, the viscosity of the coating liquid, and the like. The permeation thickness of the water-soluble resin into the paper substrate 1 can be measured from an enlarged photograph of a cross section using an optical microscope, a scanning electron microscope or the like.

[Characteristics of paper base materials for foam insulation paper containers]
(Basis weight)
The basis weight of the foamed insulating paper container paper base material 3 is preferably 100 to 400 g/m ² , more preferably 200 to 400 g/m ² , and still more preferably 220 to 400 g/m ² , and particularly preferably. Is 260 to 350 g/m ² .
When the basis weight is 100 g/m ² or more, the thermoplastic resin layer 4 is sufficiently foamed by the water content of the paper base material 1 and the like, and thus the foamed insulating paper container 8 obtained is gripped by hand. It is hard to feel the heat when you do. On the other hand, when the basis weight is 400 g/m ² or less, the rigidity of the foam insulation paper container 8 does not become too large, and the moldability tends to be improved.

(density)
The density of the foamed thermal insulation paper container paper base material 3 is preferably 0.60 to 1.05 g/cm ³ . When the density is 0.60 g/cm ³ or more, the paper strength required for the foam insulation paper container 8 is easily obtained. On the other hand, when the density is 1.05 g/cm ³ or less, when the thermoplastic resin layer 4 is foamed, water vapor sufficiently permeates the foamed heat-insulating paper container paper base material 3, so that the foamability of the thermoplastic resin layer 4 is increased. Is improved, and it is difficult to feel the heat when the obtained foam insulating paper container 8 is gripped by hand.

(Paper thickness)
The paper thickness of the foamed insulating paper container paper base material 3 is preferably 130 to 430 μm, more preferably 230 to 430 μm, and further preferably 250 to 430 μm.
When the paper thickness is 130 μm or more, the thermoplastic resin layer 4 is sufficiently foamed due to the water content of the paper base material 1 or the like, so that when the obtained foam insulation paper container 8 is gripped by hand. It is hard to feel the heat. On the other hand, when the paper thickness is 430 μm or less, the rigidity of the foam insulation paper container 8 does not become too large, and the suitability for molding tends to be improved.

(Foam insulation paper container paper base material air resistance)
The air permeation resistance per unit weight of the foamed thermal insulation paper container paper base material 3 is preferably 1.0 to 6.0 s/g/m ² . The air permeation resistance per basis weight of the foamed heat-insulating paper container paper base material 3 increases or decreases the air permeation resistance of the paper base material 1 or increases or decreases the formation amount of the water-soluble resin layer 2 laminated on the paper base material 1. Can be adjusted.

When the air permeation resistance per grammage is 1.0 s/g/m ² or more, the permeation amount of water vapor is appropriately suppressed, so that the foaming of the thermoplastic resin layer 4 is made uniform, so that foaming The beauty of the heat insulating paper container 8 is improved. On the other hand, when the air permeation resistance per basis weight is 6.0 s/g/m ² or less, it is possible to sufficiently foam the thermoplastic resin layer 4 without excessively impeding the permeation of water vapor. The heat insulating property of the heat insulating paper container 8 is improved.
The air permeation resistance per basis weight is more preferably 1.2 s/g/m ² or more, further preferably 1.5 s/g/m ² or more, from the viewpoint of obtaining better beauty. .. The air permeation resistance per basis weight is more preferably 4.7 s/g/m ² or less, and further preferably 4.5 s/g/m ² or less, from the viewpoint of obtaining better heat insulation properties. ..
The air resistance is measured according to the Oken type tester method of JIS P 8117:2009.

(amount of water)
The amount of water in the paper base material 3 of the foam insulation paper container is preferably 4.5 to 8.0%, more preferably 5.0 to 7.5%. Another representation of the water content, preferably from ^{13.5g / m 2 ~24.0g / m 2} , can also be more preferably represented as a 15.0g ^{/ m 2} ~22.5g ^/ m 2 This notation shows the same water content as the above notation.
When the amount of water in the foam base material 3 is 4.5% or more, a sufficient thickness of the foamed resin layer 9 can be obtained. On the other hand, when it is 8.0% or less, over-foaming is unlikely to occur and beauty is not easily impaired.
The amount of water in the foam insulating paper container paper base material 3 should be controlled by, for example, increasing or decreasing the relative humidity of the storage environment in which the foam insulating heat paper container paper base material 3 is stored in a paper container until it is formed and foamed. You can

[Foam insulation paper container sheet]
As shown in FIG. 3, a foam insulating paper container sheet 5 of the present embodiment includes a foam insulating paper container paper base material 3 having a water-soluble resin layer 2 on both sides of a paper base material 1, and a foam insulating heat paper container paper base material. 3 and a thermoplastic resin layer 4 laminated on the water-soluble resin layer 2 on one side. As described above, the water-soluble resin layer 2 may be provided on only one side of the paper base material 1.
When the foamed heat-insulating paper container sheet 5 is heat-treated, the water contained in the paper base material 1 and the water-soluble resin layer 2 is evaporated, and the generated steam causes the thermoplastic resin layer 4 to become the foamed resin layer 9.
Hereinafter, the foam insulating paper container sheet 5 will be described, but the description of the components already described will be omitted.

(Thermoplastic resin layer)
As the thermoplastic resin layer 4, any thermoplastic resin of crystalline resin and amorphous resin can be used as long as it can be formed on the water-soluble resin layer 2 and can be foamed with water. ..
Examples of the crystalline resin include polyolefin resins such as polyethylene, polypropylene and polymethylpentene, polyester resins and the like. Examples of the amorphous resin include polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene (ABS) resin, acrylic resin, and modified polyphenylene ether (PPE). In addition, biodegradable resins such as polylactic acid (PLA), polyglycolic acid (PGA), and polybutylene succinate (PBS) can be used for the purpose of reducing the environmental load.

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 layers may be used. Among the above-mentioned thermoplastic resins, polyethylene is preferable because it is excellent in extrusion laminating property and foaming property.
The thickness of the thermoplastic resin layer 4 is not particularly limited, but from the viewpoint of heat insulation and workability, the thickness is preferably 30 to 80 μm.

(Transpiration suppression layer)
Further, as shown in FIG. 2, a transpiration preventing layer 10 made of a high melting point thermoplastic resin having a melting point higher than that of the thermoplastic resin layer 4 or a metal may be provided on the foam insulating paper container sheet 5. The evaporation suppression layer 10 may be formed by stacking a plurality of the above substances.
When the evaporation suppression layer 10 is laminated on the surface of the paper base material 1 on which the thermoplastic resin layer 4 is not present, water vapor is evaporated from the surface of the paper base material 1 on which the thermoplastic resin layer 4 is absent when the thermoplastic resin layer 4 is foamed. It can be suppressed. When the evaporation of water vapor is suppressed, most of the water vapor generated from the paper base material 1 goes to the thermoplastic resin layer 4, so that the foamability of the thermoplastic resin layer 4 can be improved.

  It is preferable that the evaporation prevention 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 because it is possible to prevent the liquid or the like filled in the container from penetrating into the paper base material 1. The melting point of the thermoplastic resin used for the evaporation suppression layer 10 may be a temperature at which the water in the paper substrate 1 or the like does not melt when heated and evaporated, but is preferably 125° C. or higher.

The difference in melting point between the thermoplastic resin used for the thermoplastic resin layer 4 and the thermoplastic resin used for the evaporation suppression layer 10 is preferably 5° C. or more.
The difference in melting point when a plurality of types of resins are laminated means that the resin having the highest melting point among the resins used for the thermoplastic resin layer 4 and the lowest melting point among the resins used for the evaporation suppression layer 10. The difference in melting point from the resin having

[Method for forming thermoplastic resin layer]
The thermoplastic resin layer 4 and the evaporation suppression layer 10 may be laminated on the paper base material 1 by appropriately using various known methods such as an extrusion laminating method and a wet laminating method, but the thermoplastic resin layer is a single layer. In this case, it is preferable to use the extrusion laminating method. Operating conditions of the extrusion laminating method are generally such that the melting temperature is about 200 to 370° C. and the laminating speed is about 30 to 300 m/min.
When a plurality of layers are provided in the evaporation suppression layer 10, the so-called coextrusion laminating method is preferable from the viewpoint of the adhesion between the foamed heat insulating paper substrate and the evaporation suppression layer and the production efficiency.

[Molding of foam insulation paper container]
The foam insulating paper container sheet is formed into a container shape, for example, as follows.
First, various patterns, barcodes, etc. are printed at predetermined locations on the foamed insulating paper container sheet 5, and then punched into a predetermined shape to prepare a body member blank and a bottom plate member blank.
Only one of the body member blank and the bottom plate member blank may be made from the foam insulating paper container sheet 5 depending on the degree of heat insulation desired for the foam insulating paper container 8.

  The thermoplastic resins used for the body member blank and the bottom plate member blank may be the same or different, but if they are the same type, the body member 6 and the bottom plate member 7 are simultaneously foamed at the same temperature. Therefore, heating conditions such as heating temperature and time are used. Management becomes easier. The body member blank and the bottom plate member blank thus obtained are assembled and molded by a general cup molding machine to obtain a paper container.

[Bubbling by heat treatment]
The paper container is subjected to heat treatment by any means such as hot air, electric heat, or electron beam to vaporize the water contained in the paper base material 1 of the body member blank or the bottom plate member blank, and the generated water vapor causes thermoplasticity. By foaming the resin layer 4 to form the foamed resin layer 9, the foamed insulating paper container 8 is obtained. The heating temperature and time are not particularly limited, but the heating temperature is preferably about 5 to 10° C. higher than the melting point of the thermoplastic resin of the thermoplastic resin 4 and lower than the melting point of the thermoplastic resin of the evaporation suppression layer 10.
Generally, the heating temperature is about 100 to 200° C., and the heating time is about 1 to 6 minutes.

The foamed resin layer 9 thus foamed preferably has a thickness of 800 to 1500 μm.
If the thickness of the foamed resin layer 9 is 800 μm or more, sufficient heat insulation can be obtained. On the other hand, when the thickness of the foamed resin layer 9 is 1500 μm or less, the beauty is improved. The foam insulating paper container 8 can be used as a foam insulating paper container for filling hot coffee or the like, a foam insulating paper container for instant food into which hot water is poured, and the like.

[Properties of foam insulation paper container]
In a foamed heat-insulating paper container, it is also important to have the feel and comfort of holding it by hand. If the foamed resin layer of the foamed heat-insulating paper container is too soft, the pressure due to gripping causes it to be recessed too much, and the heat of the contents is transmitted to the skin, making it difficult to hold. On the other hand, if the foamed resin layer is too hard, the elastic touch peculiar to the foamed resin layer will be lost.
The present inventors, after the study, if the compression energy and compression recovery of the foam insulation paper container is within a predetermined range, a good feel is obtained due to the compatibility of the softness and the difficulty of depression of the foam insulation paper container. I found that I can be. The compression energy and compression recoverability of the foam insulation paper container will be described in detail below.

(Compression energy)
The compression energy is a value representing the integral of the load applied to the measurement target and the depth of the recess generated in the measurement target due to the load, and the larger the value of the compression energy, the more easily the measurement target is compressed and soft. Can be evaluated. The compression energy of the foam insulation paper container can be controlled by, for example, increasing or decreasing the degree of foaming of the foam resin layer, in other words, the size of the foam cell. The larger the foamed cells of the foamed resin layer and the larger the amount of air contained therein, the softer the foamed heat-insulating paper container tends to be, and the compression energy tends to increase.
The compression energy of the foam insulation paper container 8 measured using a KES-FB3-AUTO-A automated compression tester (manufactured by Kato Tech Co., Ltd.) is 0.10 to 0.95 N·m/m ² , and is 0. It is preferably 25 to 0.75 N·m/m ² . In the measurement, first, in an environment compliant with ISO187 (temperature 23±1° C., relative humidity 50±2%), cut the bottom of the foam insulation paper container with a cutter or the like, and make a cut along the generatrix on the side of the truncated cone. Put in one place and open in a fan shape. The fan-shaped sample is placed between the pressure plate and the pressure receiving plate of 2 cm ² so that the foamed surface faces upward, and the pressure plate is lowered at a speed of 50 seconds/mm.

The foamed heat-insulating paper container 8 having a compression energy of less than 0.10 N·m/m ² is too stiff and loses the touch peculiar to foaming, and is inferior in touch. On the other hand, the foamed heat-insulating paper container 8 having a compression energy of more than 0.95 N·m/m ² is too soft and is too recessed when it is gripped by the hand, so that the temperature of the contents can be easily transmitted to the hand.

(Compression recovery)
The compression recoverability is a value showing the recoverability from the depression due to the pressurization of the measurement target, and the closer the compression recoverability value is to 100%, the better the recoverability after compression can be evaluated. The compression recovery property of the foam insulation paper container can be controlled by, for example, increasing or decreasing the degree of foaming of the foam resin layer, in other words, the size of the foam cell. The larger the foamed cells of the foamed resin layer and the more air they contain, the softer the foamed heat-insulating paper container tends to be, and the compression recovery tends to be lower.
The compression recovery property of the foam insulation paper container 8 measured using a KES-FB3-AUTO-A automated compression tester (manufactured by Kato Tech Co., Ltd.) is 55 to 90%, preferably 67 to 85%. .. In the measurement, first, in an environment compliant with ISO187 (temperature 23±1° C., relative humidity 50±2%), cut the bottom of the foam insulation paper container with a cutter or the like, and make a cut along the generatrix on the side of the truncated cone. Put in one place and open in a fan shape. The fan-shaped sample is placed by placing the sample between the pressure plate and the pressure receiving plate of 2 cm ² so that the foamed surface faces upward, and lowering the pressure plate at a speed of 50 seconds/mm.

  The foamed heat-insulating paper container 8 having a compression recovery of less than 55% lacks a recovery force from compression and is excessively recessed when grasped by a hand, so that the temperature of the content is easily transmitted to the hand. On the other hand, the foam insulation paper container 8 having a compression recovery rate of more than 90% loses the feeling peculiar to foaming because it is too concave due to pressure, and is inferior in touch.

(Surface roughness)
The surface roughness of the outermost layer of the foam insulating paper container 8 measured using a high-definition shape measuring system KS-1100 (KEYENCE) is preferably 5 to 75 μm, and more preferably 15 to 60 μm.
The surface roughness referred to here is an arithmetic average height that represents the average of the absolute values of the differences in the height of each point with respect to the average surface of the outermost layer surface. The average surface indicates the average height of the evaluation points. In the measurement, first, in an environment compliant with ISO25178 (temperature 23±1° C., relative humidity 50±2%), cut the bottom of the foam insulation paper container with a cutter or the like, and make a cut along the generatrix on the side surface of the truncated cone. Put in one place and open in a fan shape. The fan-shaped sample was placed on the measuring table so that the foamed surface faced up, and the height of the outermost surface of the test piece of 1 cm ² at a moving speed of 7500 μm and a measurement pitch of 10 μm was measured.

  The foamed heat insulating paper container 8 having a surface roughness of less than 5 μm tends to have a slippery surface and thus have a poor gripping property. On the other hand, the surface of the foam insulation paper container 8 having a surface roughness of more than 75 μm has a rough feel and is inferior to the touch.

Below, the measuring method implemented about the foaming insulation paper container paper base material is shown.
The freeness of the pulp was measured according to JIS P8121:2012.
The basis weight of the foamed thermal insulation paper container paper base material was measured according to JIS P8124:2011.
The density of the paper base material of the foam insulation paper container was measured according to JIS P8118:1998.
The air permeation resistance per basis weight of the foam heat insulating paper container paper base material was measured according to the Oken type tester method described in JIS P8117:2009.

Below, the measuring method implemented about the foam insulation paper container is shown.
The compression energy and the compression recoverability of the foamed thermal insulation paper container were measured using a KES-FB3-AUTO-A automated compression tester (manufactured by Kato Tech Co., Ltd.) in an environment compliant with ISO187 (temperature 23±1° C., relative humidity 50). (±2%), a sample was placed between a 2 cm ² pressure plate and a pressure receiving plate, and the pressure plate was lowered at a speed of 50 seconds/mm for measurement.
As the surface roughness, the difference in height at each point with respect to the average surface of the foamed resin layer was taken, and the average of the absolute values (arithmetic mean height) was measured. The measurement was performed using a high-definition shape measuring system KS-1100 (KEYENCE) in an environment (temperature 23±1° C., relative humidity 50±2%) compliant with ISO25178, with a moving speed of 7500 μm and a measurement pitch of 10 μm of 1 cm ² . It was performed by measuring the height of the surface of the test piece.

[Example 1]
(Foam insulation paper container paper base material)
40 parts of acacia wood pulp, which is hardwood pulp, and 60 parts of eucalyptus wood pulp, which is also hardwood pulp, were mixed and beaten to a freeness of 430 ml to obtain a pulp slurry. With respect to 100% of this pulp slurry, 0.5% by mass of cationized starch in terms of solid content, 0.1% by mass of polyacrylamide-based paper strengthening agent (PAM-based paper strengthening agent), and alkyl ketene dimer-based sizing agent 0 30% by mass and 0.1% by mass of polyamide polyamine epichlorohydrin-based resin (PAE-based wet paper strength enhancer) were added to prepare a stock material slurry, and paper was made by a five-layer fourdrinier paper machine. Cationized starch was spray-coated between the layers at a coating amount of 1.0 g/m ² to obtain a paper base material having 5 pulp layers.

Then, polyvinyl alcohol (PVA) (manufactured by Nippon Vine Povar Co., Ltd., product name: JM17, saponification degree 96.5 mol%) was applied as a water-soluble resin on both sides of the obtained paper base material by a rod coater. It was coated and dried so that the solid content was 0.08 g/m ² (0.16 g/m ^{2 on} both sides), and a foam heat insulating paper container paper base material was obtained. The permeation thickness of PVA into the paper substrate was 18.5 μm.
The foamed thermal insulation paper container paper base material of Example 1 has a basis weight of 300 g/m ² , a density of 0.86 g/cm ³ , a Oken smoothness of 80 seconds, a texture index of 85, a water content of 18.9 g/m ² , and a basis weight. The air resistance per unit amount was 2.85 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 755 ppm.

(Foam insulation paper container sheet)
Foamed thermal insulation paper container A high melting point thermoplastic resin (medium density polyethylene, density 940 kg/m ³ , melting point 133° C.) having a thickness of 40 μm is melted on one surface of the paper substrate at a melting temperature of 360° C. and a laminating speed of 50 m. Extruded at / min. After that, a cooling roll and a nip roll (JIS A hardness: 70) were used to press and press 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 melted on the other surface of the foamed heat-insulating paper container paper base material to a thickness of 50 μm at a melting temperature of 360° C. and a laminating speed of 50 m/ Extruded in minutes. Then, a cooling roll and a nip roll (JIS A hardness: 70) were used to press and press-bond at a linear pressure of 2 kgf/cm to form a thermoplastic resin layer to obtain a foam insulating paper container sheet.

(Foam insulation paper container)
A container having an upper diameter of 100 mm, a lower diameter of 95 mm, and a height of 110 mm from a body member made of a foamed heat-insulating paper container sheet A and a bottom member made of a foam heat-insulating paper container sheet provided with only a high melting point thermoplastic resin layer on one surface. A cylindrical container was prepared so that the thermoplastic resin layer of the body member was on the outside. Next, the cylindrical container was heated with a dryer at a temperature of 120° C. for 6 minutes to foam the thermoplastic resin layer, thereby obtaining a cylindrical foam insulation paper container A.
The foamed thermal insulation paper container A had a compression energy of 0.24 N·m/m ² , a compression recovery property of 78%, and a surface roughness of 25 μm.

[Example 2]
A foam insulation paper container paper base material was prepared in the same manner as in Example 1 except that the coating amount of PVA was 0.10 g/m ² (0.20 g/m ^{2 on} both sides) in terms of solid content on one side. Obtained. The permeation thickness of PVA into the paper substrate was 19.0 μm.
The foamed thermal insulation paper container paper base material of Example 2 has a basis weight of 300 g/m ² , a density of 0.90 g/cm ³ , a Oken type smoothness of 101 seconds, a texture index of 64, a water content of 23.0 g/m ² , and a basis weight. The air permeation resistance per unit amount was 5.70 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 800 ppm.
The foamed heat-insulating paper container of Example 2 prepared using the paper base material in the same manner as in Example 1 had a compression energy of 0.72 N·m/m ² , a compression recovery property of 68%, and a surface roughness of It was 55 μm.

[Example 3]
Foamed thermal insulation paper container paper substrate in the same manner as in Example 1 except that the coating amount of PVA was 0.12 g/m ² (0.24 g/m ^{2 on} both sides) in terms of solid content on one side. Got The permeation thickness of PVA into the paper substrate was 19.0 μm.
The foam insulation 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 Oken smoothness of 80 seconds, a texture index of 92, a water content of 18.0 g/m ² , and a basis weight. The air permeation resistance per unit amount was 4.60 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 731 ppm.
The foamed heat-insulating paper container prepared in the same manner as in Example 1 using the foam heat-insulating paper container of Example 3 had a compression energy of 0.15 N·m/m ² , a compression recovery property of 85%, and a surface roughness of It was 11 μm.

[Example 4]
Foamed insulation paper container paper base material in the same manner as in Example 1 except that the coating amount of PVA was 0.15 g/m ² (0.30 g/m ^{2 on} both sides) in terms of solid content on one side. Got The permeation thickness of PVA into the paper substrate was 19.5 μm.
The foam insulation paper container paper base material of Example 4 has a basis weight of 300 g/m ² , a density of 0.87 g/cm ³ , a Oken smoothness of 81 seconds, a texture index of 80, a water content of 21.0 g/m ² , and a base. The air permeation resistance per amount was 5.80 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 844 ppm.
The foamed heat-insulating paper container of Example 4 was produced in the same manner as in Example 1 using the paper base material, the compression energy was 0.18 N·m/m ² , the compression recovery was 75%, and the surface roughness was It was 12 μm.

[Example 5]
20 parts of hardwood pulp acacia wood and 80 parts of hardwood pulp eucalyptus wood pulp were mixed and beaten to obtain a pulp slurry, and in the same manner as in Example 1, foamed insulating paper container paper base I got the wood. The permeation thickness of PVA into the paper substrate was 18.5 μm.
The foam insulation 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 Oken type smoothness of 75 seconds, a texture index of 80, a water content of 18.0 g/m ² , and a basis weight. The air permeation resistance per unit amount was 1.65 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 314 ppm.
The foamed heat-insulating paper container of Example 5 was produced in the same manner as in Example 1 using the paper base material, the compression energy was 0.33 N·m/m ² , the compression recovery was 73%, and the surface roughness was It was 33 μm.

[Example 6]
Foamed thermal insulation paper container paper base was prepared in the same manner as in Example 1 except that PVA was coated by a blade coater so that the solid content was 0.06 g/m ² on one side (0.12 g/m ^{2 on} both sides). I got the wood. The permeation thickness of PVA into the paper substrate was 18.5 μm.
The foamed insulation paper container paper base material of Example 6 has a basis weight of 300 g/m ² , a density of 0.86 g/cm ³ , a Oken smoothness of 80 seconds, a texture index of 90, a water content of 13.5 g/m ² , and a basis weight. The air permeability resistance per unit amount was 2.40 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 816 ppm.
The foamed heat-insulating paper container of Example 6 prepared in the same manner as in Example 1 using the paper base material had a compression energy of 0.12 N·m/m ² , a compression recovery property of 82%, and a surface roughness of It was 10 μm.

[Example 7]
Foamed thermal insulation paper container paper base was prepared in the same manner as in Example 1 except that PVA was coated by a blade coater so that the solid content was 0.06 g/m ² on one side (0.12 g/m ^{2 on} both sides). I got the wood. The permeation thickness of PVA into the paper substrate was 18.5 μm.
The foam insulation paper container paper base material of Example 7 has a basis weight of 300 g/m ² , a density of 0.86 g/cm ³ , a Oken smoothness of 80 seconds, a texture index of 90, a water content of 17.7 g/m ² , and a basis weight. The air permeation resistance per unit amount was 2.44 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 747 ppm.
The foamed heat-insulating paper container of Example 7 prepared in the same manner as in Example 1 using the paper base material had a compression energy of 0.21 N·m/m ² , a compression recovery property of 80%, and a surface roughness of It was 18 μm.

[Example 8]
Instead of PVA, starch except that coated so as to ^{1.50g / m 2 (3.00g / m} 2 on both sides) in solid per side component, in the same manner as in Example 1, foam insulating paper container A paper substrate was obtained. The permeation thickness of starch into the paper substrate was 80.0 μm.
The foam insulation paper container paper base material of Example 8 has a basis weight of 300 g/m ² , a density of 0.86 g/cm ³ , a Oken smoothness of 80 seconds, a texture index of 89, a water content of 17.8 g/m ² , and a basis weight. The air resistance per unit amount was 1.70 s/g/m ² , and the total content of linear alcohol and linear fatty acid was 795 ppm.
The foamed heat-insulating paper container of Example 8 was produced in the same manner as in Example 1 using the paper base material, the compression energy was 0.29 N·m/m ² , the compression recovery was 78%, and the surface roughness was It was 28 μm.

[Example 9]
80 parts of acacia wood pulp which is hardwood pulp and 20 parts of radiata pine wood pulp which is softwood pulp were mixed and beaten to obtain a pulp slurry. Further, in place of PVA, starch, was applied so that the 1.50 g / ^{m 2} (in both 3.00 g / ^{m 2)} at a solid per side minute. A foamed heat-insulating paper container paper base material was obtained in the same manner as in Example 1 except that the type of pulp and the coating of starch were different. The permeation thickness of starch into the paper substrate was 80.0 μm.
The foam insulation paper container paper base material of Example 9 has a basis weight of 300 g/m ² , a density of 0.90 g/cm ³ , a Oken type smoothness of 78 seconds, a texture index of 78, a water content of 17.8 g/m ² , and a basis weight. The air permeation resistance per amount was 3.15 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 1871 ppm.
The foamed thermal insulation paper container prepared in the same manner as in Example 1 using the foamed thermal insulation paper container of Example 9 had a compression energy of 0.65 N·m/m ² , a compression recovery property of 70%, and a surface roughness of It was 44 μm.

[Example 10]
Instead of PVA, starch, except that was coated so as to ^{1.00g / m 2 (2.00g / m} 2 on both sides) in solid per side content by a blade coater, in the same manner as in Example 1, A paper base material for a foam insulation paper container was obtained. The permeation thickness of starch into the paper substrate was 50.0 μm.
The foamed insulation paper container paper base material of Example 10 has a basis weight of 300 g/m ² , a density of 0.87 g/cm ³ , a Oken smoothness of 85 seconds, a texture index of 63, a water content of 18.0 g/m ² , and a basis weight. The air permeability resistance per unit amount was 1.50 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 763 ppm.
The foamed heat-insulating paper container prepared in the same manner as in Example 1 using the foamed heat-insulating paper container of Example 10 had a compression energy of 0.40 N·m/m ² , a compression recovery property of 72%, and a surface roughness of It was 37 μm.

[Example 11]
Instead of PVA, starch, except that was coated so as to ^{1.10g / m 2 (2.20g / m} 2 on both sides) in solid per side content by a blade coater, in the same manner as in Example 1, A paper base material for a foam insulation paper container was obtained. The permeation thickness of starch into the paper substrate was 60.0 μm.
The foamed insulation paper container paper base material of Example 11 has a basis weight of 300 g/m ² , a density of 0.86 g/cm ³ , a Oken smoothness of 79 seconds, a texture index of 80, a water content of 17.5 g/m ² , and a basis weight. The air resistance per unit amount was 1.65 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 722 ppm.
The foamed heat-insulating paper container of Example 11 was prepared in the same manner as in Example 1 using the paper base material, the compression energy was 0.20 N·m/m ² , the compression recovery was 70%, and the surface roughness was It was 25 μm.

[Comparative Example 1]
10 parts of acacia wood pulp which is a hardwood pulp and 90 parts of eucalyptus wood pulp which is also a hardwood pulp were mixed and beaten to obtain a pulp slurry. Further, PVA was applied by a blade coater so that the solid content per one surface was 0.04 g/m ² (0.08 g/m ^{2 on} both surfaces). A foamed insulating paper container paper base material was obtained in the same manner as in Example 1 except that the type of pulp and the coating of PVA were different. The permeation thickness of PVA into the paper substrate was 16.0 μm.
The foam insulation 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 Oken smoothness of 92 seconds, a texture index of 90, a water content of 22.5 g/m ² , and a basis weight. The air resistance per unit amount was 0.75 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 189 ppm.
The foamed heat-insulating paper container of Comparative Example 1 prepared using the paper base material in the same manner as in Example 1 had a compression energy of 0.98 N·m/m ² , a compression recovery property of 53%, and a surface roughness of It was 79 μm.

[Comparative example 2]
5 parts of acacia wood pulp, which is hardwood pulp, and 95 parts of eucalyptus wood pulp, which is also hardwood pulp, were mixed and beaten to obtain a pulp slurry. Further, PVA was coated so as to ^{0.60g / m 2 (1.20g / m} 2 on both sides) in solid per side minute. A foamed insulating paper container paper base material was obtained in the same manner as in Example 1 except that the type of pulp and the coating of PVA were different. The permeation thickness of PVA into the paper substrate was 23.0 μm.
The foam insulation paper container paper base material of Comparative Example 2 has a basis weight of 300 g/m ² , a density of 0.91 g/cm ³ , a Oken type smoothness of 88 seconds, a texture index of 85, a water content of 17.6 g/m ² , and a basis weight. The air resistance per unit amount was 6.85 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 135 ppm.
The foamed heat-insulating paper container of Comparative Example 2 prepared using the paper base material in the same manner as in Example 1 had a compression energy of 0.09 N·m/m ² , a compression recovery property of 75%, and a surface roughness of It was 15 μm.

[Comparative Example 3]
Eucalyptus pulp, which is a hardwood pulp, was beaten to obtain a pulp slurry. Further, water was applied instead of PVA and dried (the coating amount of the water-soluble resin and the permeation thickness of the water-soluble resin into the paper substrate cannot be measured. did). A foamed insulating paper container paper base material was obtained in the same manner as in Example 1 except that the type of pulp and the water-soluble resin were different.
The foam insulation paper container paper base material of Comparative Example 3 has a basis weight of 300 g/m ² , a density of 0.87 g/cm ³ , a Oken type smoothness of 89 seconds, a texture index of 90, a water content of 23.1 g/m ² , and a basis weight. The air resistance per unit amount was 0.55 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 100 ppm.
The foamed heat-insulating paper container prepared in the same manner as in Example 1 using the foamed heat-insulating paper container of Comparative Example 3 had a compression energy of 1.05 N·m/m ² , a compression recovery property of 53%, and a surface roughness of It was 80 μm.

[Comparative Example 4]
Example 1 except that 10 parts of hardwood pulp, acacia pulp, 60 parts of hardwood pulp, 60 parts of eucalyptus pulp, and 30 parts of softwood pulp, radiata pine pulp, were mixed and beaten to obtain a pulp slurry. In the same manner as above, a foam base material for heat insulating paper container was obtained. The permeation thickness of PVA into the paper substrate was 18.5 μm.
The foamed insulation paper container paper base material of Comparative Example 4 has a basis weight of 300 g/m ² , a density of 0.89 g/cm ³ , a Oken type smoothness of 80 seconds, a texture index of 70, a water content of 18.9 g/m ² , and a basis weight. The air resistance per unit amount was 2.85 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 2639 ppm.
The foamed heat-insulating paper container prepared in the same manner as in Example 1 by using the foam heat-insulating paper container of Comparative Example 4 had a compression energy of 0.99 N·m/m ² , a compression recovery property of 58%, and a surface roughness of It was 82 μm.

[Comparative Example 5]
Foamed thermal insulation paper container paper base material was obtained in the same manner as in Example 1 except that 5 parts of hardwood pulp, acacia pulp, and 95 parts of hardwood pulp, eucalyptus pulp, were mixed and beaten to obtain a pulp slurry. Got The permeation thickness of PVA into the paper substrate was 18.5 μm.
The foamed insulation paper container paper base material of Comparative Example 5 has a basis weight of 300 g/m ² , a density of 0.88 g/cm ³ , a Oken type smoothness of 80 seconds, a texture index of 70, a water content of 18.9 g/m ² , and a basis weight. The air permeation resistance per amount was 2.85 s/g/m ² , and the total content of the linear alcohol and the linear fatty acid was 121 ppm.
The foamed heat-insulating paper container prepared in the same manner as in Example 1 using the foamed heat-insulating paper container of Comparative Example 5 had a compression energy of 1.10 N·m/m ² , a compression recovery property of 50%, and a surface roughness of It was 90 μm.

[Evaluation methods]
The following evaluations were performed on the foam insulation paper container sheet obtained as described above. The evaluation results of the examples and comparative examples are shown in Table 1.

(Thermal insulation properties)
An A4 size sample was cut out from the obtained sheet for foamed insulating paper containers. A cylinder was prepared so that the thermoplastic resin layer was on the outside. Then, hot air was used to foam the thermoplastic resin layer outside the cylinder at a heating temperature of 120° C. for a heating time of 6 minutes.
The expansion ratio was calculated from the thickness of the resulting foamed insulation paper before and after foaming, and evaluated according to the following criteria. In addition, ⊚, ◯, and Δ are acceptable, and x is not acceptable.
A: The expansion ratio is 21 times or more, and the heat insulation property is sufficient.
Good: The expansion ratio is 19 times or more and less than 21 times, and the heat insulating property is sufficient.
Δ: Foaming ratio is 15 times or more and less than 19 times, and has a heat insulating property.
X: The expansion ratio is less than 15 times, and the heat insulating property is insufficient.

(Beauty)
A square test piece having a side of 100 mm was cut out from the obtained sheet for a foamed insulating paper container. Then, using a hot air, the thermoplastic resin layer was foamed at a heating temperature of 120° C. for 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. In addition, ⊚, ◯, and Δ are acceptable, and x is not acceptable.
⊚: No excessive foaming is observed, the formed foam cells are small and uniform, and the surface is almost flat.
◯: No over-foaming is observed, the formed foam cells are small and the surface is almost flat, but the size of the foam cells varies.
Δ: The foamed cells formed are slightly large and the size varies, but the surface irregularities are small and no excessive foaming is observed.
X: Large unevenness on the surface due to occurrence of over-foaming.

(Sensory evaluation of touch)
90° C. hot water was placed in a foamed insulating paper container, and after 3 minutes, the outer wall surface of the container was touched by hand and evaluated according to the following criteria. In addition, ⊚, ◯, and Δ are acceptable, and x is not acceptable.
⊚: Not too hot, the container can be sufficiently held by hand, and has elasticity and smoothness particularly suitable for use.
◯: Slightly hot, but can hold the container by hand, and has elasticity and smoothness suitable for use.
Δ: It is hot and it is possible to hold the container sufficiently by hand, but it has elasticity and smoothness that does not hinder the use.
X: It is considerably hot and it is difficult to hold the container by hand, which is not suitable for use.

As can be seen from Table 1, the foamed heat-insulating containers of Examples 1 to 11 were excellent in any of the properties of heat insulation, beauty, and touch sensory evaluation.
The foamed insulating paper containers of Comparative Examples 1, 3, and 5 were inferior in touch feeling because the compression energy was too high and the compression recovery property was too low. The foamed heat-insulating paper container of Comparative Example 2 had a compression recovery property within a predetermined range, but the compression energy was too low. Although the foam heat-insulating paper container of Comparative Example 4 had a compression recovery property within a predetermined range, the compression energy was too high, and thus the touch feeling was inferior.

1 Paper Base Material 2 Water-Soluble Resin Layer 3 Foam Insulating Paper Container Paper Base Material 4 Thermoplastic Resin Layer 5 Foam Insulating Paper Container Sheet 6 Body Member 7 Bottom Plate Member 8 Foam Insulating Paper Container 9 Foaming Resin Layer 10 Evaporation Suppression Layer 11 Pulp Layer 12 Starch layer

Claims (7)

From the outside in order, a body member including a foamed resin layer made of a thermoplastic resin, a paper base layer and a thermoplastic resin layer,
A foam insulation paper container comprising a bottom plate member,
Compression recovery is 55-90%,
A foamed heat-insulating paper container having a compression energy of 0.10 to 0.95 N·m/m ² .   The foamed heat-insulating paper container according to claim 1, wherein the outermost layer has a surface roughness of 5 to 75 µm. The main component of the paper base material constituting the paper base material layer is cellulose pulp,
A water-soluble resin layer is provided between the paper base layer and the foamed resin layer,
Air permeation resistance per basis weight of the paper base material is 0.35 to 1.92 s/g/m< ² >. The foam insulation paper container according to claim 1 or 2, wherein.   The paper base material is selected from a group consisting of monohydric linear alcohols having at least one carbon number selected from the group consisting of 24, 26 and 28 and a group consisting of 24, 26 and 28. The foamed heat-insulating paper container according to claim 3, which contains a total of 200 to 2500 ppm of at least one kind of linear fatty acid having carbon number.   The proportion of acacia pulp in the cellulose pulp is 10% by mass or more, and the foam insulation paper container according to claim 3 or 4.   The foamed heat-insulating paper container according to any one of claims 3 to 5, wherein the paper base material is a multilayer material.   The foamed heat-insulating paper container according to any one of claims 1 to 6, wherein the resin forming the foamed resin layer is polyethylene.

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