JP7285359B2 - Coated tableware and paper tableware - Google Patents

Description

The present invention relates to coated tableware paper.

Conventionally, as disposable tableware, those molded from plastic resin have been widely used. In addition, conventional plastic resins, bamboo, and wood have the problem of high manufacturing costs due to the necessity of special molding for knife applications. In addition, since plastic products pollute the ocean and affect the ecosystem of marine organisms, in recent years, from the viewpoint of environmental protection, the establishment of alternative technology to plastic tableware has been demanded. Especially in Europe, there is a demand for eco-friendly and recyclable paper products. On the other hand, in the prior art, paper-made stirring sticks and spoons with improved water resistance and hot water resistance have been proposed as alternative materials (see, for example, Patent Document 1).

JP-A-2003-79505

However, the conventional techniques described above are still insufficient in imparting the toughness and durability required for cutlery applications such as tableware and knives. Therefore, in order to use paper for cutlery such as tableware and knives, improvement in toughness and durability is required.

The present invention was made based on the above circumstances, and it is an object of the present invention to provide a coated tableware paper that is excellent in toughness and durability and that can be used for paper tableware to replace conventional plastic paper knives. aim.

The invention made to solve the above problems comprises a pair of surface layers and a plurality of intermediate layers arranged between the pair of surface layers, wherein the surface layers and intermediate layers are bleached softwood kraft pulp and bleached hardwood kraft pulp. is the main component, the mass ratio of the bleached softwood kraft pulp to the bleached hardwood kraft pulp in the surface layer is 5/95 or more and 15/85 or less, and the mass of the bleached softwood kraft pulp in the intermediate layer to the bleached hardwood kraft pulp The coated tableware paper has a ratio of 30/70 or more and 40/60 or less, and the surface layer has a surface coating layer containing completely saponified polyvinyl alcohol on the surface.

By blending the bleached softwood kraft pulp and the bleached hardwood kraft pulp in the coated tableware paper, the thickness of the paper can be increased and the rigidity and durability can be improved. In addition, by setting the mass ratio of the softwood bleached kraft pulp to the hardwood bleached kraft pulp in the surface layer to 5/95 or more and 15/85 or less, the hardwood kraft pulp is relatively rigid and easy to increase in density. The surface layer of can obtain high density and rigid characteristics, and is excellent in strength. Furthermore, the surface layer has a high effect of suppressing permeation into the interior of moisture or oil components derived from the object such as food. On the other hand, by setting the mass ratio of the bleached softwood kraft pulp to the bleached hardwood kraft pulp in the middle layer to 30/70 or more and 40/60 or less, the middle layer contains a large amount of flexible softwood kraft pulp. Be flexible. The coated tableware paper has a multi-layered structure in which a pair of surface layers having rigidity that is hard but easy to break and a middle layer having flexibility are combined. While ensuring, distortion and breakage can be suppressed. Further, the coated dishware paper has a surface coating layer containing completely saponified polyvinyl alcohol on the surface of the surface layer, so that good surface strength can be imparted to the coated tableware paper. Therefore, the coated tableware paper has excellent toughness and durability, and is suitable for paper tableware to replace conventional resin disposable tableware.

The coating amount of the surface coating layer is preferably 1 g/m ² or more and 5 g/m ² or less. Thus, the coating amount of the surface coating layer is within the above range, so that the coated tableware paper can further improve toughness and durability.

The ratio of the total basis weight of the pair of surface layers to the total basis weight is preferably 25.0% or more and 35.0% or less. In the coated tableware paper comprising a pair of rigid surface layers and a flexible middle layer, by setting the ratio of the total basis weight of the pair of surface layers to the above range, the property of being resistant to bending is imparted. can be done.

It is preferable that the total number of the middle layers is four or more. When the total number of middle layers is 4 or more, the toughness and durability of the coated tableware paper can be further improved.

Another invention made to solve the above problems is a paper tableware made of the coated tableware paper. Since the paper tableware is made of the coated tableware paper, it is excellent in toughness and durability.

ADVANTAGE OF THE INVENTION According to this invention, the coated tableware paper which is excellent in toughness and durability and can be used for the paper tableware which replaces the conventional plastic tableware can be provided.

Hereinafter, the coated tableware paper according to one embodiment of the present invention will be described in detail.
<Coated paper for tableware>
The coated tableware paper includes a pair of surface layers and a plurality of intermediate layers arranged between the pair of surface layers. The "tableware" in the present invention is a broad concept including not only tableware such as plates, bowls, chopsticks, cups, coasters, trays, muddlers, spoons, and forks, but also kitchen utensils such as knives and kitchen knives. The coated tableware paper is particularly suitable for cutlery such as knives and kitchen knives.

[surface]
The coated tableware paper comprises a pair of surface layers. The surface layer is mainly composed of softwood bleached kraft pulp and hardwood bleached kraft pulp. In addition, a "main component" means a component with the largest content on a mass basis.

The mass ratio of the bleached softwood kraft pulp to the bleached hardwood kraft pulp in the surface layer is 5/95 or more and 15/85 or less. By setting the mass ratio of the bleached softwood kraft pulp to the bleached broadleaf kraft pulp in the above range, the surface layer has high density and high rigidity because it contains a large amount of hardwood kraft pulp that is relatively rigid and easily densified. Excellent strength. Furthermore, the surface layer has a high effect of suppressing permeation into the interior of moisture or oil components derived from the object such as food. In addition, by combining with a flexible middle layer, it is possible to suppress distortion and breakage while ensuring elasticity.

Each layer of the coated tableware paper is optionally made of, for example, ECF (Elemental Chlorine Free) pulp, TCF (Total Chlorine Free) pulp, unbleached kraft pulp (UKP), hardwood unbleached kraft pulp (LUKP), softwood Chemical pulp such as unbleached kraft pulp (NUKP), hardwood semi-bleached kraft pulp (LSBKP), softwood semi-bleached kraft pulp (NSBKP), hardwood sulfite pulp, softwood sulfite pulp, or non-wood fibers such as kenaf, hemp, and reed Various known pulps such as pulp chemically or mechanically produced from cellulose can be used in combination as appropriate. The coated tableware paper is used for paper tableware and comes into direct contact with objects such as food. Therefore, other pulps used in the coated tableware paper are preferably chemical pulps, and more preferably ECF pulp, TCF pulp, and unbleached kraft pulp (UKP). ECF pulp is a chlorine-free bleached chemical pulp made without chlorine (Cl ₂ ) and bleached with chlorine dioxide (ClO ₂ ). TCF pulp is completely chlorine-free bleached chemical pulp manufactured by bleaching with oxygen (O), hydrogen peroxide (P), and ozone (Z) without using chlorine (Cl ₂ ). That is, since ECF pulp and TCF pulp contain very little or no chlorine ions, they have the advantage of being less likely to generate organic chlorine compounds such as dioxins even when incinerated at low temperatures. can be reduced. In addition, by using unbleached kraft pulp, it is possible to mimic the color of wood (ice bars, etc.), and by omitting the bleaching process, it is possible to reduce the environmental load by reducing energy consumption and _CO2 emissions. .

The lower limit of the Canadian Standard Freeness (CSF) of the pulp used for the surface layer of the coated tableware is preferably 410 ml. If the CSF of the pulp used for the surface layer is less than 410 ml, the rigidity of the coated tableware paper may decrease. On the other hand, the upper limit of the CSF of the pulp used for the surface layer is preferably 470 ml. If the CSF exceeds 470 ml, it becomes difficult to adjust the pulp fiber orientation in the paper machine, resulting in poor texture of the coated tableware paper, and there is a risk that the paper strength will be reduced for use as a paper container. The coated tableware paper is made by mixing bleached softwood kraft pulp and bleached broadleaf kraft pulp with high freeness, thereby increasing the paper thickness and improving the stiffness. Here, Canadian Standard Freeness (CSF) is defined as disaggregated pulp by disaggregating in accordance with the pulp disaggregation method of JIS-P8220-1 (2012), and this disaggregated pulp is JIS-P8121-2 (2012) Canadian It is a value measured according to the standard freeness test method.

[middle class]
A plurality of intermediate layers are provided between the pair of surface layers. The middle layer is mainly composed of softwood bleached kraft pulp and hardwood bleached kraft pulp. Further, the mass ratio of the bleached softwood kraft pulp to the bleached hardwood kraft pulp in the middle layer is 30/70 or more and 40/60 or less. By setting the mass ratio of the bleached softwood kraft pulp to the bleached hardwood kraft pulp in the middle layer within the above range, the middle layer has good flexibility because it contains a large amount of the flexible softwood kraft pulp. Therefore, as described above, the coated tableware paper is excellent in toughness and durability because the flexible middle layer is combined with the pair of surface layers that have rigidity and tend to be hard but tend to break easily.

The lower limit of the Canadian Standard Freeness (CSF) of the pulp used for the middle layer of the coated tableware paper is preferably 375 ml. If the CSF is less than 375 ml, the dewatering property in the paper machine may deteriorate, and furthermore, it may become difficult to adjust the pulp fiber orientation. On the other hand, the upper limit of the CSF of the pulp used for the middle layer is preferably 465 ml. If the CSF exceeds 465 ml, fibrillation is less likely to result in lower interlaminar strength. Furthermore, it is preferable that the Canadian standard freeness of the pulp used for the middle layer is smaller than the Canadian standard freeness of the pulp used for the pair of surface layers from the viewpoint of maintaining the Z-axis strength of the middle layer and ensuring elastic force.

The total number of intermediate layers is preferably four or more. When the total number of middle layers is 4 or more, the toughness and durability of the coated tableware paper can be further improved. From the viewpoint of maintaining interlayer strength, the upper limit of the total number of intermediate layers is preferably 8 or less.

[Additive]
The coated dishware paper preferably contains a sizing agent and a paper strength agent as papermaking additives in the surface layer and the middle layer.

(Sizing agent)
A sizing agent can be added to each layer of the coated tableware paper in order to further suppress penetration of moisture or oil derived from an object such as food into the interior. Examples of sizing agents include styrenic sizing agents, alkyl ketene dimers (AKD), alkenyl succinic anhydrides (ASA), neutral rosin sizing agents, rosin sizing agents, modified rosin emulsion sizing agents, and the like. Among these, rosin sizing agents and modified rosin emulsion sizing agents are preferred.

The rosin sizing agent is conventionally known in the field of paper manufacturing, and is not particularly limited. Rosin-based substances include, for example, reinforced rosins obtained by modifying rosins such as gum rosin, wood rosin and tall oil rosin with α,β-unsaturated carboxylic acids such as fumaric acid, maleic acid and acrylic acid or their anhydrides, and the above-mentioned Rosin esters obtained by reacting rosins with polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and diglycerin can be mentioned. In the present invention, the rosin-based sizing agent also includes those obtained by emulsifying these alone or a mixture thereof, and those obtained by emulsifying them alone and then mixing them. Furthermore, the emulsified product to which various polymers are added in order to further improve the sizing property is also included.

The content of the sizing agent in the surface layer is preferably 0.5 kg/t or more and 5.0 kg/t or less in solid content. Moreover, the content of the sizing agent in the middle layer is preferably 2.0 kg/t or more and 5.0 kg/t or less in terms of solid content. In addition, "kg/t" shows the mass (kg) per 1t of pulp. Water resistance can be improved by setting the content of the sizing agent within the above range.

(paper strength agent)
The coated tableware paper can have a paper strength agent sizing agent added to each layer. By adding a paper strength agent, each layer can be given various strengths suitable for use as paper tableware.

Various known paper strength agents such as polyacrylamide resins, polyamide resins, polyamine resins, acrylic resins, melamine resins, urea resins, and polyamide epichlorohydrin resins can be used. Among these, amphoteric paper strength agents are preferably used. Examples of amphoteric polyacrylamides include copolymers of acrylamide with the above anionic monomers and cationic monomers, Mannich-modified products of copolymers of acrylamide with the above anionic monomers, Hoffmann decomposition products, and the like. According to the findings of the present inventors, amphoteric polyacrylamide is particularly preferable, and since amphoteric polyacrylamide has a self-fixing function, even if it is added to improve inter-paper strength, it does not become excessively cationic. , the modified rosin emulsion sizing agent can be stably fixed.

The content of the paper strength agent in each layer is preferably 12 kg/t or more and 20 kg/t or less in terms of solid content. By setting the content of the paper strength enhancer within the above range, it is possible to impart various paper strengths such as interlaminar strength to the coated tableware paper. If the content of the paper strength agent is less than the above range, the interlaminar strength may not be sufficient. On the other hand, when the content of the paper strength agent exceeds the above range, the improvement in interlaminar strength is almost leveled off, and the yield of the added paper strength agent decreases, causing stains, foaming, etc. in the paper machine system. There is a risk that it will occur and the operability will decrease.

(Other additives)
In addition, the coated tableware paper may contain other various additives for papermaking within a range that does not impair the intended effect of the present invention. Other additives that can be added to the coated tableware paper include, for example, known papermaking chemicals.

[Surface coating layer]
The coated dishware paper has a surface coating layer containing completely saponified polyvinyl alcohol on the surface of the surface layer. It is necessary to form a relatively strong film on the surface that comes into contact with the object such as food in order to suppress the penetration of moisture or oil derived from the object such as food into the interior and to maintain the surface strength. By having the coated tableware paper with the surface coating layer, the coated tableware paper has good surface strength and is highly effective in suppressing permeation of water or oil components into the interior.

The coating amount of the completely saponified polyvinyl alcohol is preferably 0.5 g/m ² or more and 5.0 g/m ² or less from the viewpoint of imparting good surface strength.

The surface coating layer preferably contains a wax-based sizing agent. As wax-based sizing agents, paraffin wax-based sizing agents, microcrystalline wax-based sizing agents, carnauba wax (carnauba wax)-based sizing agents, etc. can be used. It is preferable to incorporate a paraffin wax-based sizing agent because it can impart water resistance and water resistance.

The coating amount of the wax-based sizing agent is preferably 0.1 g/m ² or more and 0.5 g/m ² or less from the viewpoint of improving water repellency and water resistance.

The surface coating layer preferably contains a surface sizing agent. Examples of surface sizing agents include styrene-acrylic sizing agents, alkyl ketene dimers (AKD), alkenyl succinic anhydrides (ASA), neutral rosin sizing agents, and rosin sizing agents. In addition to these sizing agents, acrylic sizing agents are preferably used.

The coating amount of the surface sizing agent is preferably 0.2 g/m ² or more and 1.0 g/m ² or less from the viewpoint of suppressing insufficient strength due to moisture when used as tableware.

The surface coating layer may contain starch, polyacrylamide and the like in addition to polyvinyl alcohol, paraffin wax and surface sizing agent. In addition, the surface coating layer may further contain, for example, known additives for papermaking.

As the surface coating layer, (1) a form in which the fibers on the surface of the surface layer are impregnated with the aqueous composition, (2) a form in which a resin layer is formed by the aqueous composition on the surface of the surface layer, and (3) the surface layer. (4) a form in which the surface of the fiber is coated with the aqueous composition, or (4) a form in which these are combined. Also, a part of the surface coating layer composition may be impregnated.

From the viewpoint of improving the surface strength, the lower limit of the coating amount of the surface coating layer is preferably 1.0 g/m ² , more preferably 2.0 g/m ² . The upper limit of the coating amount of the surface coating layer is preferably 5.0 g/m ² , and 4.0 g/m ² from the viewpoint of suppressing the deterioration of the paper texture and the occurrence of staining due to blocking during the processing process. more preferred.

[Physical properties of coated tableware paper]
(basis weight)
Basis weight is measured according to JIS-P8124 (2011). The basis weight of each layer of the coated tableware paper does not need to be uniform, and the basis weight of the surface layer and the middle layer is not particularly limited, but the basis weight of one surface layer is 90.0 g / m ² or more and 300.0 g/m ² or less is preferable. Moreover, the basis weight of the entire middle layer is preferably 450.0 g/m ² or more and 925.0 g/m ² or less.

The lower limit of the basis weight of the entire coated dishware paper is preferably 700.0 g/m ² and more preferably 750.0 g/m ² from the viewpoint of obtaining sufficient rigidity. The upper limit of the basis weight of the entire coated dishware paper is preferably 1000.0 g/m ² , more preferably 900.0 g/m ² . If the basis weight exceeds 1000.0 g/m ² , sufficient rigidity is likely to be obtained, but creases may be likely to occur when passing through paper rolls during papermaking.

The ratio of the total basis weight of the pair of surface layers to the basis weight of the entire coated tableware paper is preferably 25.0% or more and 35.0% or less. In the coated tableware paper comprising a pair of rigid surface layers and a flexible middle layer, by setting the ratio of the total basis weight of the pair of surface layers to the above range, the property of being resistant to bending is imparted. can be done.

(paper thickness)
The paper thickness is measured in accordance with “Paper and paperboard—Testing methods for thickness and density” described in JIS-P8118 (2014). The paper thickness of the coated tableware paper is preferably 950 μm or more and 1,300 μm or less. When the thickness of the coated tableware paper is within the above range, peeling of the paper layer of the coated tableware paper can be suppressed.

(density)
The density of the coated tableware paper is preferably 0.73 g/cm ³ or more and 0.88 g/cm ³ or less. When the density of the coated tableware paper is within the above range, the rigidity is excellent while enabling a low basis weight and weight reduction.

(moisture)
The water content of the coated tableware paper measured according to JIS-P8127 (2010) is preferably 9.0% or more and 11.0% or less. When the water content of the coated tableware paper is within the above range, the flexibility is improved, so workability in a folding machine and breakage of the folded portion when producing tableware using the coated tableware paper The suppression effect can be improved.

(ash)
Ash content is measured according to JIS-P8251 (2003). The density of the coated tableware paper is preferably 0.1% or more and 10.0% or less. When the density of the coated tableware paper is within the above range, the curl can be adjusted to be flat and the decrease in interlayer strength can be suppressed.

(Surface strength)
The surface strength was evaluated according to JAPAN TAPPI Paper Pulp Test Method No. Measured according to the "Surface Strength Test Method" by 1 m-72. The lower limit of the surface strength of the coated tableware paper is preferably 10A. When the surface strength of the coated tableware paper is within the above range, it is possible to improve the abrasion resistance during removal of the surface layer, transportation, and processing.

(Cobb size degree)
Cobb size degree is measured using distilled water at 23° C. in accordance with JIS-P8140 (1998). The upper limit of the Cobb sizing degree of the coated tableware paper is preferably 50 g/m ² . If the hump sizing degree of the coated tableware paper is equal to or higher than the above upper limit, the coated tableware paper may cause waviness or wrinkles due to moisture absorption.

(Z-axis strength)
As for the Z-axis strength of the waterproof and greaseproof paper, JAPAN TAPPI paper pulp test method No. 18-1:2000, the Z-axis strength is preferably 380 kN/m ² or more. By having the above Z-axis strength, it is possible to suppress the occurrence of delamination and wrinkles during tableware molding.

The coated tableware paper is excellent in toughness and durability, and can be used for paper tableware to replace conventional plastic tableware.

[Method for producing coated tableware paper]
Although the method for producing the coated tableware paper is not particularly limited, it can be produced, for example, by the following steps using a known multilayer paper machine.
(1) A slurry obtained by dispersing pulp fibers in water is mixed with an additive corresponding to each paper layer as necessary to prepare a stock for each paper layer.

(2) Next, using these raw material slurries, the surface layer, single layer or multi-layer middle layer and surface layer are formed by a paper machine in a neutral range so that the pH of the coated tableware paper is 6 or more and 8 or less. Paper is made by papermaking.
The papermaking method is not particularly limited, and a known papermaking machine such as a fourdrinier, a cylinder, a hybrid former, a gap former, or the like is used to make paper in three or more layers. In the papermaking process, a coating apparatus such as a size press, a metering size press, a gate roll coater, or the like can be used to apply a coating liquid to the surface of the surface layer to form a surface coating layer.

(3) Next, it is pressed with pressure rolls to remove moisture.

(4) Next, it is dried with a dryer cylinder.
After drying, a calendering device such as a nip calender, a super calender, a machine calender, or a soft calender may be used for smoothing treatment. By performing a smoothing treatment, the coated tableware paper is imparted with high glossiness and can be suitably used for paper tableware having a high-class appearance.

(5) Finally, the paper is wound on a reel to obtain a coated tableware paper.

<paper tableware>
The paper tableware is composed of the coated tableware paper. Since the paper tableware is made of the coated tableware paper, it is excellent in toughness and durability.

The coated tableware paper is excellent in toughness and durability, and can be used for paper tableware to replace conventional plastic tableware.

<Other embodiments>
The present invention is not limited to the above-described embodiments, and can be implemented in various modified and improved modes in addition to the above-described modes.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples.

Methods for measuring physical properties in Examples and Comparative Examples are as follows.
[Freeness (mL)]
The resulting coated tableware paper is defiberized according to the pulp disintegration method of JIS-P8220-1 (2012) to obtain disintegrated pulp, and the disintegrated pulp is subjected to Canadian standard filtration of JIS-P8121-2 (2012). It was measured according to the water content test method.

[Basis weight (g/m ² )]
It was measured in accordance with "Paper and paperboard- Basis weight measurement method" described in JIS-P8142 (1998).

[Paper thickness (μm)]
It was measured in accordance with "Paper and paperboard-Testing methods for thickness and density" described in JIS-P8118 (2014).

[Density (g/cm ³ )]
It was measured in accordance with "Paper and paperboard-Testing methods for thickness and density" described in JIS-P8118 (2014).

[moisture]
Measured according to JIS-P8127 (2010).

[ash]
Measured according to JIS-P8251 (2003).

[Surface strength]
JAPAN TAPPI No. It was measured according to the wax surface strength test method of No. 1.

[Hump size]
Measured according to JIS-P8140 (1998).

[Z-axis strength]
JAPAN TAPPI paper pulp test method No. 18-1:2000.

[Bending strength]
The bending strength was measured with a digital force gauge (manufactured by Imada Co., Ltd.) under the following test conditions. The food coated paper was fixed to a three-point folding jig, and the force gauge was lowered. The load at that time was taken as the bending strength (N). The test environment was set at a temperature of 26° C. and a humidity of 70%.

[Example 1]
(1) The composition of the surface layer and middle layer is shown below.
(surface)
Into 100 parts pulp slurry of 10:90 NBKP:LBKP in 440 mL of Freeness, the following ingredients were added.
Modified rosin emulsion-based sizing agent (“AL1344” from Seiko PMC):
Solid content 2.5 kg/pulp t
Acrylamide-based paper strength agent (“Harmide RB-28” from Harima Kasei Co., Ltd.):
Solid content 16.0 kg/pulp t
(middle class)
Into 100 parts pulp slurry of 35:65 NBKP:LBKP in 440 mL of freeness, the following ingredients were added.
Modified rosin emulsion-based sizing agent (“AL1344” from Seiko PMC):
Solid content 3.5 kg/pulp t
Acrylamide-based paper strength agent (“Harmide RB-28” from Harima Kasei Co., Ltd.):
Solid content 16.0 kg/pulp t
(2) This pulp slurry was made into a 7-layer structure of a surface layer, a 5-layer intermediate layer and a surface layer using a wire part multi-layer paper machine. The basis weight of each layer was 125 g/m ² for the surface layer, 626.5 g/m ² for the middle layer, and 125 g/m ² for the back layer, and the total basis weight was 880.0 g/m ² .
(3) On the surface of the surface layer, a coating liquid containing polyvinyl alcohol and paraffin wax was calender-coated at 3.5 g / m ² so that the following coating amount was applied to form a surface coating layer. A coated tableware paper No. 1 was obtained.
Polyvinyl alcohol (“Gosenol N300” manufactured by Nippon Synthetic Chemical Co., Ltd.): 2.7 g/m ²
Paraffin wax (“Haricoat RK” manufactured by Harima Chemicals): 0.2 g/m ²
Styrene/methacrylic acid copolymer resin surface sizing agent (mass average molecular weight 9,000, melting point 100°C, "Kycoat SA20" SP value 10.0 manufactured by Kindai Kagaku Kogyo Co., Ltd.): 0.6 g/m ²

[Examples 2 to 2 and Comparative Examples 1 to 6]
Tableware of Examples 2 to 12 and Comparative Examples 1 to 6 in the same manner as in Example 1 except that the types, contents and physical properties of the raw materials were as shown in Tables 1 and 2. A coated paper was obtained. Comparative Example 6 used 80% partially saponified polyvinyl alcohol. "-" in Table 1 below indicates that the corresponding component was not used.

[evaluation]
Table 3 shows the evaluation results of each coated tableware paper obtained.

As shown in Table 3 above, Examples 1 to 12 of the coated tableware paper exhibited good results in all of surface strength, hump sizing degree, Z-axis strength and bending strength.

On the other hand, the mass ratio of the bleached softwood kraft pulp to the bleached hardwood kraft pulp in the surface layer is less than 5/95 or more than 15/85, and the mass ratio of the bleached softwood kraft pulp to the bleached hardwood kraft pulp in the middle layer is less than 30/70 or 40/ Comparative Examples 1 to 6, in which the strength was more than 60 or the surface layer contained partially saponified polyvinyl alcohol, were inferior in strength.

The coated tableware paper of the present invention can be suitably used for paper tableware.

Claims (7)

A pair of surface layers and a plurality of intermediate layers arranged between the pair of surface layers,
The surface layer and the middle layer contain a sizing agent and a paper strength agent,
The surface layer has a surface coating layer containing completely saponified polyvinyl alcohol on the surface,
basis weight is 700 g/m ² or more and 1000 g/m ² or less;
Density is 0.73 g/cm ³ or more and 0.88 g/cm ³ or less,
JAPAN TAPPI paper pulp test method No. 1 m-72 has a surface strength of 13 A or more, as measured in accordance with the "Surface Strength Test Method";
JAPAN TAPPI paper pulp test method No. 18-1: Z-axis strength measured in accordance with 2000 is 380 kN / ^m2 or more,
A coated tableware paper having a bending strength of 5.5 N or more, which is a load when a force gauge is lowered while being fixed to a three-point bending jig. The Canadian standard freeness of the pulp used for the surface layer is 410 ml or more and 470 ml or less,
Canadian standard freeness of the pulp used for the middle layer is 375 ml or more and 465 ml or less,
The basis weight of the entire middle layer is 450.0 g / m ² More than 925.0g/m ² The coated tableware paper according to claim 1, wherein: 3. The coated tableware paper according to claim 1, wherein the surface strength is 18A or less. 4. The coated tableware paper according to claim 1, claim 2, or claim 3, wherein the Z-axis strength is 430 kN/ ^m2 or less. The coated tableware paper according to any one of claims 1 to 4, wherein the bending strength is 5.8 N or less. 6. The coated tableware paper according to any one of claims 1 to 5, wherein the total number of said middle layers is 3 or more. Paper tableware made of the coated tableware paper according to any one of claims 1 to 6 .