JP6702496B1 - LAMINATED PAPER, LAMINATED PAPER PAPER BASE, PAPER CONTAINER AND LAMINATED PAPER MANUFACTURING METHOD - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily separate a paper base material and a thermoplastic resin layer, and to easily recycle raw materials, a laminated paper base material, a paper container using the laminated paper, and the laminated paper. A method of manufacturing the same is provided. A laminated paper for a paper container having a paper base material containing cellulose pulp as a main component and a thermoplastic resin layer laminated on at least one surface of the paper base material. Contains at least one of a linear fatty acid and a linear alcohol, the melting point of the linear fatty acid and the linear alcohol is 80 to 100° C., and the linear fatty acid and the linear chain in the paper substrate are A laminated paper for a paper container, wherein the total content of alcohol is 100 to 2500 ppm. The present invention also relates to a laminated paper base material for the paper container, a paper container using the laminated paper for the paper container, and a method for manufacturing the laminated paper for the paper container. [Selection diagram] None

Description

TECHNICAL FIELD The present invention relates to a laminated paper, a laminated paper paper base material, a paper container, and a laminated paper manufacturing method.

In liquid paper containers used for milk packs and the like, laminated paper in which a thermoplastic resin layer such as polyethylene is laminated on a paper base material mainly composed of pulp fibers to impart water resistance is often used. This type of liquid paper container is separated into a paper base material and a thermoplastic resin layer after use, the paper component is used as a waste paper raw material, and the thermoplastic resin layer of relatively high purity is RPF (Refuse Paper & Plastic). It may be recovered and used as a raw material for fuel (solid fuel) and recycled plastic. However, since it is generally not easy to peel the thermoplastic resin layer from the paper base material, the recycling efficiency is not always high, and further improvement has been demanded.

Therefore, a technique for recycling the raw material of the liquid paper container has been developed. For example, in Patent Document 1, the outermost layer made of an olefin resin, a paper base layer, an adhesion adjusting layer, an adhesive resin layer, a barrier layer, a resin film layer, a laminate having an innermost layer containing an olefin resin, There is disclosed a liquid paper container in which at least the outermost layer and the paper base material layer are separated from the barrier layer in the region between the strip-shaped separator and the body score line.

Further, in Patent Document 2, there is an opportunity for impregnating a paper layer at a side end corner portion of a top forming plate of a gable top type container with a paper strengthening agent to separate the paper-based layer from the plastic-based layer. A liquid paper container having a structure that is easy to make is disclosed.

JP, 2012-166796, A JP, 2000-185729, A

The liquid paper container of Patent Document 1 is a liquid paper container in which the paper base material layer and the barrier layer can be easily peeled off, but it is composed of a number of layers and is cut to improve the peeling property. There was room for improvement in sex. Further, the liquid paper container of Patent Document 2 is also a liquid paper container provided with a location that serves as a trigger when the layer mainly composed of paper and the layer mainly composed of plastic are peeled off. Since only a part of the container and most of the paper container remains firmly adhered, there is room for improvement in recyclability and the like.

The present invention has been made in view of the above situation. That is, an object of the present invention is to provide a laminated paper in which the paper base material and the thermoplastic resin layer can be easily peeled off and the raw material can be easily recycled, the laminated paper paper base material, and the paper using the laminated paper. A container and a method for manufacturing the laminated paper.

The present inventors proceeded with the study on a paper base material containing a specific amount of a specific linear fatty acid or linear alcohol. As a result, the paper base material containing a specific amount of a specific type of linear fatty acid or linear alcohol firmly adheres to the thermoplastic resin layer at the time of production, but after that, the component concerned surface of the paper base material over time. It was found that the paper base material and the thermoplastic resin layer can be easily peeled off by bleeding in the vicinity. The present invention has been completed based on these findings. That is, the present invention has the following configurations.

(1) A laminated paper for a paper container, comprising a paper base material containing cellulose pulp as a main component, and a thermoplastic resin layer laminated on at least one surface of the paper base material, wherein the paper base material is At least one of a straight-chain fatty acid and a straight-chain alcohol, the straight-chain fatty acid and the straight-chain alcohol have a melting point of 80 to 100° C., and the straight-chain fatty acid and the straight-chain alcohol in the paper base material. Laminated paper for paper containers, wherein the total content of the above is 100 to 2500 ppm.

(2) The laminated paper for a paper container according to (1), wherein the linear fatty acid has 24, 26 or 28 carbon atoms, and the linear alcohol has 26 or 28 carbon atoms.

(3) The paper base material contains both the linear fatty acid and the linear alcohol, and the ratio of the linear alcohol content to the linear fatty acid content is 3.0 to 33.3%. The laminated paper for a paper container according to (1) or (2) above.

(4) The paper according to any one of (1) to (3), wherein the fiber roughness of the disaggregation raw material of the paper base material is 0.020 to 0.18 mg/m, as measured by Kajaani Fiber Lab. Laminated paper for containers.

(5) The laminated paper for paper containers according to any one of (1) to (4), which has a basis weight of 150 to 500 g/m ² .

(6) The laminated paper for paper containers according to any one of (1) to (5), wherein the paper base material is a multi-layered paper.

(7) A laminated paper base material for paper containers, which comprises cellulose pulp as a main component, and contains at least one of a linear fatty acid and a linear alcohol, and the melting point of the linear fatty acid and the linear alcohol is 80. It is -100 degreeC, and the total content of the said linear fatty acid and the said linear alcohol is 100-2500 ppm, The laminated paper paper base material for paper containers characterized by the above-mentioned.

(8) The laminated paper base material for paper containers according to (7), which is a multi-layered paper.

(9) A paper container using the laminated paper for paper container according to any one of (1) to (6).

(10) The paper container according to (9), which is for liquids.

(11) A method for producing a laminated paper for a paper container according to any one of (1) to (6), which comprises a step of making a paper base material containing cellulose pulp as a main component, and the paper base material. And a laminating step of laminating a thermoplastic resin layer on at least one surface of the paper making step and at least one of the laminating steps A method for producing a laminated paper for a paper container, which is characterized by bringing them into contact with each other.

(12) The paper container according to (11), wherein the paper base material is a multi-layer paper, and the paper base material is made by using a multi-layer paper machine in the paper making step. Laminated paper manufacturing method.

In the laminated paper of the present invention and the paper container using the laminated paper, the paper base material and the thermoplastic resin layer can be easily peeled off, and the raw materials can be easily recycled.

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

The laminated paper of the present embodiment has a paper base material containing cellulose pulp as a main component, and a thermoplastic resin layer laminated on at least one surface of the paper base material. Hereinafter, each material constituting the laminated paper will be described.

[Paper substrate]
The paper base material is mainly composed of cellulose pulp. Here, the main component means a component accounting for 50% by mass or more of the components constituting the paper base material. Examples of the cellulose pulp include wood pulp and non-wood pulp. Examples of the wood pulp include bleached kraft pulp of softwood (NBKP), softwood kraft pulp (NKP), bleached kraft pulp of hardwood (LBKP), hardwood kraft pulp (LKP), and other wood pulp, sulfite pulp ( Examples thereof include chemical pulp such as SP), dissolving pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), and oxygen bleached kraft pulp (OKP). Further, semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-groundwood pulp (CGP), mechanical pulps such as groundwood pulp (GP) and thermomechanical pulp (TMP, BCTMP) can be mentioned. Examples of the non-wood pulp include hemp, bagasse, cotton and the like. These pulps may be used alone or in combination of two or more. From the viewpoint of quality and cost, wood pulp such as acacia lumber and eucalyptus lumber, which are LKP, are suitable as the pulp constituting the paper base material. The raw material pulp is not limited to virgin pulp.

The fiber roughness of the disaggregation raw material of the paper base material, which is measured by Kajaani Fiber Lab, is preferably 0.020 to 0.18 mg/m. The disaggregation method of the paper base material is performed according to JIS P8220-1:2012. Generally, the smaller the fiber roughness is, the finer the fibers are, and the fibers are densely packed in the paper base material, so that the bleeding of linear fatty acids and linear alcohols is uniform and the surface smoothness of the paper base material is improved. It is preferable that the uniform adhesion of the laminate is improved by the improvement. Further, since the surface smoothness of the paper base material is improved, the printability on the surface of the paper base material is improved, and the surface smoothness after lamination is also improved, so that the printability on the laminate surface is also improved. However, if the fiber roughness is less than 0.020 mg/m, it is difficult to obtain the paper thickness. Further, the projected length weighted average fiber length of the fibers constituting the paper base material is preferably 0.40 to 2.00 mm. The average fiber length of the fibers is measured according to JIS P8226:2006.

The paper base material may be a single-layered paper or a multi-layered paper (multi-layered paper) composed of two or more layers. In the case of multilayer paper, the number of layers is preferably 2 or more and 6 or less, and more preferably 3 or more and 5 or less. In the multi-layered paper, the raw material composition of each layer, the basis weight, the papermaking conditions and the like can be adjusted as desired, and a starch or a paper-strengthening agent which enhances interlayer adhesion may be contained between the layers. By such an operation, the bleeding of the linear fatty acid or the linear alcohol can be adjusted, and the texture and the smoothness can be improved to improve the surface property.

(Straight chain fatty acid and straight chain alcohol)
The paper base material contains at least one of a linear fatty acid and a linear alcohol. A straight-chain fatty acid is a monovalent carboxylic acid having a straight-chain alkyl group. The linear alcohol is a monovalent alcohol having a linear alkyl group.

Cellulose pulp generally contains straight chain fatty acids and straight chain alcohols. In plants, linear fatty acids and linear alcohols are generally synthesized starting from acetic acid having 2 carbon atoms. Therefore, the carbon number of the synthesized fatty acid or alcohol is even.

The present inventor investigated the peeling behavior of a laminated paper comprising a paper base material containing a linear fatty acid or a linear alcohol and a thermoplastic resin layer. As a result, when a linear fatty acid or a linear alcohol having a melting point of 80 to 100° C. is present in the paper base material, the linear fatty acid or the linear alcohol is converted into a paper base material with the lapse of time after the production of laminated paper. It was found to bleed near the surface (release to the surface). Further, the straight-chain fatty acid or straight-chain alcohol bleeds near the surface of the paper base material and then enters the interface with the thermoplastic resin layer. As a result, it has been found that, after laminating the paper base material and the thermoplastic resin layer, the paper base material and the thermoplastic resin layer are easily peeled off after a certain amount of time has elapsed.

In the present embodiment, the melting point of the linear fatty acid and the linear alcohol is 80 to 100°C. When the melting points of the straight-chain fatty acid and the straight-chain alcohol are within the above-mentioned temperature range, a device such as a dryer heated to 100° C. or higher used in the production of the paper substrate, or heated and melted to 100° C. or higher in the laminating step Since it is melted by the heat of the thermoplastic resin, it can be uniformly distributed in the paper base material. Further, since the linear fatty acid and the linear alcohol bleed over time, the paper base material and the thermoplastic resin layer can be easily separated from each other. Linear fatty acids having a melting point of 80 to 100° C. include, for example, behenic acid having 22 carbon atoms (melting point 80° C.), lignoceric acid having 24 carbon atoms (melting point 84° C.), hexacosanoic acid having 26 carbon atoms (melting point 88° C. ), octacosanoic acid having 28 carbon atoms (melting point 91° C.), and triacontanoic acid having 30 carbon atoms (melting point 94° C.). On the other hand, the linear alcohol having a melting point of 80 to 100° C. means, for example, hexacosanol having a carbon number of 26 (melting point 80° C.), octacosanol having a carbon number of 28 (melting point 83° C.), and triacontanol having a carbon number of 30 ( Melting point 86°C). Here, the melting points of the individual linear fatty acids and linear alcohols are obtained by the DSC method.

If the melting point of the straight-chain fatty acid and the straight-chain alcohol is too low, bleeding is excessively promoted in the dryer or the laminating process, so that the adhesion failure of the laminate is likely to occur. On the other hand, if the melting point is too high, it will not be melted by the heat of a drier or the like, so that the distribution of the linear fatty acid and the linear alcohol will not be uniform in the paper base material, and the components will be aggregated and hardened, so that it easily becomes a foreign substance. Become.

The total content (mass) of linear fatty acid and linear alcohol in the paper substrate is 100 to 2500 ppm, preferably 150 to 2400 ppm. Here, the total content of the linear fatty acid and the linear alcohol is the total content of the linear fatty acid and the linear alcohol having a melting point of 80 to 100°C. Here, the linear fatty acid may consist of only one type of linear fatty acid having a melting point of 80 to 100°C, or a mixture containing a plurality of types of linear fatty acid having a melting point of 80 to 100°C. May be Similarly, the linear alcohol may consist of only one type of linear alcohol having a melting point of 80 to 100°C, or a mixture containing a plurality of linear alcohols having a melting point of 80 to 100°C. May be The content of linear fatty acid or linear alcohol can be quantified by the method described below. The paper substrate may contain a linear fatty acid or a linear alcohol having a melting point of 80 to 100°C as long as the effect of the present invention is not impaired.

If the total content of the straight chain fatty acid and the straight chain alcohol is too small, the effect of facilitating the peeling of the paper base material and the thermoplastic resin layer due to bleeding is difficult to be obtained. On the other hand, if the total content of the linear fatty acid and the linear alcohol is too large, the fatty acid salt (calcium salt or the like) may be accumulated in the manufacturing apparatus and the paper substrate may be soiled. Further, if the total content of the linear fatty acid and the linear alcohol in the paper base material is too large, these compounds will be deposited in the paper base material or on the surface of the paper base material as aggregated foreign matter, and the surface of the paper base material will be precipitated. The smoothness may decrease. When the coagulated foreign matter is deposited, the uniformity of the adhesion of the laminate is also reduced, and the smoothness of the laminate surface is also reduced.

When the melting point of the straight-chain fatty acid and the straight-chain alcohol in the paper base material is within the above-mentioned temperature range and the above-mentioned content is present, there is a problem in the adhesiveness between the paper base material and the thermoplastic resin layer during the production of laminated paper. There is no. However, after the laminated paper is manufactured, it is used as a paper container, and at the end of the product life, linear fatty acid or linear alcohol bleeds near the surface of the paper base material, and the paper base material and the thermoplastic resin layer Can be controlled so that peeling can be facilitated.

The linear fatty acid having a melting point of 80 to 100° C. preferably has 24, 26 or 28 carbon atoms. The linear alcohol having a melting point of 80 to 100° C. preferably has 24, 26 or 28 carbon atoms. The straight chain fatty acid having 24, 26 or 28 carbon atoms is a monovalent straight chain fatty acid having a carbon number selected from the group consisting of 24, 26 and 28 carbon atoms. The linear alcohol having 24, 26 or 28 carbon atoms is a monovalent linear alcohol having a carbon number selected from the group consisting of 24, 26 and 28 carbon atoms.

The amount of linear fatty acid or linear alcohol contained in the cellulose pulp, which is the raw material for the paper base material, depends on the steps of cooking wood chips, which is the raw material for pulp, and recovering the fibers, washing, bleaching, and washing after bleaching. It can be adjusted in any one of a process, a paper making process, a coating process, or a plurality of processes. For example, the amount of straight-chain fatty acid or straight-chain alcohol contained in the cellulose pulp, which is a raw material of the paper base material, by addition of alkali in the washing step after bleaching, addition of oil-absorbing particles such as microtalc, and dispersant such as pitch control agent. Can be adjusted.

In addition, among tree species as a raw material of cellulose pulp, there are tree species containing a large amount of linear fatty acids or linear alcohols having 24, 26 or 28 carbon atoms. For example, acacia. Therefore, the content of the linear fatty acid and the linear alcohol in the paper base is adjusted to the above range by using the pulp of the tree species containing a large amount of these linear fatty acids or the linear alcohol as a raw material of the paper base. It can be quantified.

The ratio of the content of the linear alcohol to the content of the linear fatty acid is preferably 3.0 to 33.3%, more preferably 4.0 to 30.0%. If the amount of the linear fatty acid is too large, it may accumulate in the manufacturing apparatus in the form of calcium salt or the like, which may lead to stain of the paper substrate. On the other hand, if the amount of the linear fatty acid is too small, the surfactant effect will be insufficient and bleeding may be insufficient.

The method for incorporating the straight-chain fatty acid and the straight-chain alcohol into the paper base material is not particularly limited, and examples thereof include the following methods. Among these, the method (1) is preferable because it is not necessary to change the conventional manufacturing process.
(1) A method of using the pulp of a tree species containing a large amount of the above-mentioned straight chain fatty acid and straight chain alcohol as a raw material for a paper base material.
(2) A method of adding a predetermined amount of a chemical agent containing a straight-chain fatty acid and a straight-chain alcohol, or a component thereof, in any of the pulp manufacturing process and the paper-making paper making process.
(3) A method of impregnating a predetermined amount of a straight-chain fatty acid and a straight-chain alcohol, or a chemical containing these components, after paper-making a paper substrate.

When making a paper substrate, various internal addition aids can be appropriately selected and used as necessary. Examples of the internal additive aids include sizing agents, yield improving agents, freeness improving agents, bulking agents, paper strength improving agents, various starches such as cationized starch, sulfuric acid bands, coloring dyes, coloring pigments, and fluorescence increasing agents. Examples include whitening agents, pH adjusters, pitch control agents, preservatives, slime control agents, and the like. Further, a filler may be blended when making the paper base material. The filler may be any filler commonly used in the papermaking field and is not particularly limited. For example, by using an inorganic mineral such as talc as the filler, the linear fatty acid or linear alcohol contained in the paper substrate can be appropriately adsorbed to adjust the bleeding.

The basis weight of the paper substrate is not particularly limited, but is preferably 150 to 500 g/m ² . If it is 150 g/m ² or less, the rigidity may be insufficient when molded into a paper container. On the other hand, when it is 500 g/m ² or more, a large amount of chemicals and raw materials are used, which may result in high cost.

A water-soluble polymer layer or a coating layer containing a pigment and an adhesive as a main component may be provided on at least one surface of the paper substrate. These layers can be used alone or in combination of two or more kinds. By providing the water-soluble polymer layer or the coating layer, the degree of bleeding of the linear fatty acid or the linear alcohol can be adjusted. The water-soluble polymer is not particularly limited, but from the viewpoint of processability, polyvinyl alcohol (PVA), starches, polyacrylamides, polyethyleneimines and the like are preferable. The pigment that can be used for the coating layer is not particularly limited, and examples thereof include purified natural mineral pigments such as various kaolin, talc, or ground calcium carbonate, light calcium carbonate, or calcium carbonate and other hydrophilic materials. Composite pigments with organic compounds, satin white, lithopone, titanium dioxide, silica, alumina, aluminum hydroxide, zinc oxide, magnesium carbonate, calcined kaolin, hollow organic pigments, solid organic pigments, plastic pigments, binder pigments, plastics Examples thereof include beads, microcapsules, and the like, but are not limited to these. The method for forming the water-soluble polymer layer and the coating layer is not particularly limited, and a blade coater, a rod coater or the like can be used.

(Papermaking)
The paper base material is manufactured by making paper in the paper making process. The paper-making method of paper base material and the type of paper-making machine include known paper-making methods and paper-making machines such as fourdrinier paper machine, twin wire paper machine, cylinder paper machine, gap former, on-top former, success former and the like. Can be used and is not limited. In particular, when making multi-layer paper, it is preferable to use a multi-layer paper machine. The pH during papermaking may be any of acidic region (acidic papermaking), pseudo-neutral region (pseudo-neutral papermaking), neutral region (neutral papermaking), and alkaline region (alkaline papermaking), and is not limited. ..

[Thermoplastic resin layer]
The thermoplastic resin layer is formed by laminating the thermoplastic resin layer on a paper base material. As the thermoplastic resin, either a crystalline resin or a non-crystalline resin can be used depending on the application. As the thermoplastic resin, polyethylene (LDPE, MDPE, HDPE, LLDPE, etc.), polypropylene, polyolefin resin such as polymethylpentene, polyester resin such as PET and PBT, polyamide resin, polylactic acid, PHB, PBS, PBAT, PCL, Examples thereof include biodegradable resins such as PHBH, polystyrene, polyvinyl chloride, acrylonitrile butadiene styrene (ABS) resin, acrylic resin, and modified polyphenylene ether (PPE).

The thermoplastic resin layer may be formed as a single layer of a single resin, may be formed as a single layer by mixing a plurality of resins, or may be formed as a plurality of layers of the same kind or different kinds of resins. You may.

The thickness of the thermoplastic resin layer is not particularly limited, but is usually about 10 to 50 μm.

[Laminated paper]
The laminated paper includes a paper base material and a thermoplastic resin layer laminated on at least one surface of the paper base material. The thermoplastic resin layer may be laminated only on one side of the paper base material, or may be laminated on both sides of the paper base material. Laminated paper is manufactured by laminating a thermoplastic resin layer on at least one surface of a paper base material in a laminating step.

As a method for laminating the thermoplastic resin layer on the paper substrate, various known methods such as extrusion laminating method, dry laminating method, wet laminating method, thermal laminating method, and coextrusion laminating method can be appropriately used.

When laminating, the paper base material or the thermoplastic resin layer may be subjected to an oxidation treatment such as corona treatment or ozone treatment, if necessary. By performing these treatments, polar groups are generated on the surface of the paper base material or the thermoplastic resin layer, and the adhesiveness can be improved. These treatments may be performed on either the paper substrate or the thermoplastic resin layer, or both. Further, the number of times of these processes may be once or may be repeated a plurality of times.

At the time of manufacturing a laminated paper, a material heated to 100° C. or higher is brought into contact with a paper base material in at least one of a papermaking step and a laminating step. By contacting a material heated to 100° C. or higher with the paper base material, the linear fatty acid and the linear alcohol contained inside the paper base material are dissolved, and they are evenly distributed in the paper base material. be able to. The material heated to 100° C. or higher may be a device such as a dryer, a heating roll, a heating cylinder roll, an extruder, an infrared heater, or a thermoplastic resin at the time of lamination, and is not particularly limited. Also, the method of contacting with a heated object may be direct contact, or indirect contact through canvas, air or the like. These treatments may be performed once or may be repeated a plurality of times.

The laminated paper composed of the paper base material and the thermoplastic resin layer preferably has a basis weight of 150 to 500 g/m ² , and more preferably 200 to 400 g/m ² . If the basis weight is too small, heat will be transferred too much during the production of the laminated paper, which may cause excessive bleeding of the linear fatty acid or the linear alcohol during the production. On the other hand, if the basis weight is too large, heat is difficult to transfer during the production of the laminated paper, so that the straight-chain fatty acid or the straight-chain alcohol cannot be uniformly dispersed during the production, and bleeding does not occur uniformly, and peeling becomes difficult. There is a risk.

The laminated paper including the paper base material and the thermoplastic resin layer preferably has a thickness of 200 to 750 μm. Further, laminated paper comprising a paper substrate and the thermoplastic resin layer is preferably a density of 0.50~1.30g / cm ^3, to be 0.60~1.20g / cm ³ further preferable.

The laminated paper of the present embodiment has sufficient laminate adhesiveness from the time of manufacturing the laminated paper to the time of using it as a container. However, when the container is collected after use and reused, the adhesiveness deteriorates and the paper base material and the thermoplastic resin layer are easily separated, so that the pulp of the paper base material should be easily recycled. You can

Generally, in a recycling process in which laminated paper is separated into a paper base material mainly composed of pulp fibers and a thermoplastic resin layer, the laminated paper is put into a pulper and disaggregated. In the laminated paper of the present embodiment, the paper base material and the thermoplastic resin layer are easily separated from each other, so that the raw materials can be easily separated and can be collected and recycled.

The laminated paper is basically a laminated paper having a two-layer structure or a three-layer structure composed of a paper base material and a thermoplastic resin layer. Can be formed. For example, a thermoplastic resin layer of the same type or different types may be further provided on a laminated paper composed of a paper base material and a thermoplastic resin layer, or a layer other than the thermoplastic resin layer may be provided between the thermoplastic resin layer and the thermoplastic resin layer. Alternatively, a layer other than the thermoplastic resin layer may be provided between the paper base material and the thermoplastic resin layer. Layers other than the thermoplastic resin layer include the above-mentioned water-soluble polymer layer (PVA or the like), a coating layer containing a pigment and an adhesive as a main component, an aluminum foil (Al foil), a printing layer and the like.

Specific examples of the layer structure of laminated paper include paper base/LDPE, paper base/coating layer/LDPE, LDPE/paper base/LDPE, LDPE/paper base/coating layer/LDPE, LDPE. /PVA/paper base material/PVA/LDPE, LDPE/paper base material/LDPE/PET/LDPE, LDPE/paper base material/LDPE/Al foil/LDPE, but not limited to these.

[Paper container]
Various paper containers can be manufactured using the laminated paper of this embodiment. As a method of manufacturing the paper container, a known method can be appropriately selected and used.

[Liquid paper container]
Various liquid paper containers can be manufactured using the laminated paper of this embodiment. As a method of manufacturing the liquid paper container, a known method can be appropriately selected and used.

By manufacturing the paper container so that the thermoplastic resin layer is on the inside, the liquid of the contents is held by the thermoplastic resin layer, so the liquid penetrates into the paper base material side and the paper base material discolors. And deterioration can be suppressed.

Laminated paper provided with a thermoplastic resin layer such as PE on both the outside and the inside of a paper substrate is heat-treated at a temperature higher than the boiling point of water and the melting point of the thermoplastic resin to form the thermoplastic resin layer on the paper base. By foaming with the water content of the material, a paper container having a heat insulating property can be obtained. The heat-insulating paper container can be used as, for example, a heat-insulating paper container whose contents are a heated liquid/solid or a cooled liquid/solid.

The laminated paper of this embodiment is a liquid paper container such as a milk carton, a paper cup, a foaming cup, an ice cup, a heat insulating cup, a coffee container, an aseptic container, a paper container such as a packaging container, and a variety of packaging materials, heat insulating materials, and the like. It can be used for various purposes.

Hereinafter, the effects of the present invention will be described in detail with reference to Examples. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples represent "parts by mass" and "% by mass", respectively.

The materials used in Examples and Comparative Examples are as follows.
(1) Pulp LBKP: Acacia pulp, eucalyptus pulp NBKP: Douglas fir, radiata pine, cedar (2) Thermoplastic resin PE: LDPE manufactured by Nippon Polyethylene Co., product number LC522

Below, the measuring method implemented about the paper base material and laminated paper is shown. Unless otherwise specified, the measurement was performed in an environment of a temperature of 23° C.±1° C. and a humidity of 50±2% described in JIS P8111:1998.

(1) For the fiber morphology, the projected length weighted average fiber length and the roughness were measured according to JIS P8226:2006. A fiber length measuring device (manufactured by Metso Automation Co., Ltd., Kajaani Fiber Lab Ver4.0) was used for the measurement.
(2) Basis weight: Measured according to JIS P8124:2011.
(3) Thickness: According to JIS P8118:2014, the thickness when a pressure of 100 kPa±10 kPa was applied to the circular region (200 mm ² ) of the test piece was measured.
(4) Density: Measured according to JIS P8118:2014. The thickness was measured when a pressure of 100 kPa±10 kPa was applied to the circular region (200 mm ² ) of the test piece.
(5) Water content: Measured according to JIS P8127:2010.

The linear fatty acid and linear alcohol contents were measured as follows.
A 30 mm×30 mm paper substrate was cut out and weighed precisely. After delaminating the cut-out test piece in the thickness direction, the total amount was divided into 10 mm×10 mm small pieces. All of the divided test pieces were placed in a glass container, 0.1 ml of concentrated hydrochloric acid (12N) and 2 ml of chloroform were added, and ultrasonic treatment was performed for 30 minutes. The extract obtained at this time was filtered with a membrane filter (pore diameter 0.2 μm). The filtrate was analyzed by high performance liquid chromatography. As an eluent, acetone=50:50 containing 0.1% of methanol:trifluoroacetic acid was used, and the flow rate was 1 ml/min. The column used was a Waters X Bridge C18, 250 mm×4.6 mm I.D. In D, the temperature was 30° C. and 2 μl of the filtrate was injected. The detector used a charged particle detector to detect linear alcohols and linear fatty acids, and for each of them, the concentration in the sample was determined by the following calculation formula, and the total was calculated. The peak area value of each component is the portion surrounded by the baze line and each peak, but peaks that partially overlap were determined by peak separation according to the perpendicular method of JIS K 0124.
Calculation formula: Concentration in sample (ppm)={standard sample concentration/standard sample peak area value}×sample peak area value×2 (ml)÷{(sample mass (mg)÷1000)}

[Example 1]
(Paper substrate)
As a pulp raw material, 100 parts of LBKP (80% acacia wood, 20% eucalyptus wood) was beaten using a double disc refiner to obtain a pulp slurry. With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 1.0 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 274 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.

(Thermoplastic resin layer)
LDPE (LC522) as a thermoplastic resin was laminated on both the outer and inner surfaces of the obtained paper substrate. The lamination of the thermoplastic resin layer was performed by an extrusion laminating method at a laminating temperature of 330° C. and a laminating speed of 200 m/min. The thickness and mass of the thermoplastic resin layer were as described in Table 1, and laminated paper was obtained.

(Paper container)
After offset printing was performed on the surface of the obtained laminated paper, ruled lines were provided at necessary positions and punched into a predetermined shape to obtain a blank material. Next, a part of the resin material of the blank material was melted by frame sealing, and the body portion was bonded to obtain a cylindrical sleeve. Subsequently, this tubular sleeve was supplied to a liquid filling machine to form a bottom portion on the filling machine, and then the top portion was sealed to obtain a gable top type paper container.

[Example 2]
As a pulp raw material, 100 parts of LBKP (acacia wood 70%, eucalyptus wood 30%) was beaten using a double disc refiner to obtain a pulp slurry. With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 1.0 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 476 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Example 3]
80 parts of LBKP (60% of acacia wood, 40% of eucalyptus wood) and 20 parts of NBKP (50% of Douglas fir, 30% of radiata pine, 20% of cedar) as pulp raw materials were beaten using a double disc refiner, respectively, to obtain a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 3.0 g of oxidized starch was applied to the surface of the paper substrate with a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 152 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Example 4]
As a pulp raw material, 80 parts of LBKP (40% of acacia wood, 60% of eucalyptus wood) and 20 parts of NBKP (50% of Douglas fir, 30% of radiata pine, 20% of cedar) were beaten using a double disc refiner, respectively, to obtain a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 4.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 3.0 g of oxidized starch was applied to the surface of the paper substrate with a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 370 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Example 5]
50 parts of LBKP (50% of acacia wood, 50% of eucalyptus wood) and 50 parts of NBKP (50% of Douglas fir, 30% of radiata pine, 20% of cedar) as pulp raw materials were beaten using a double disc refiner, respectively, to obtain a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 4.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 3.0 g of oxidized starch was applied to the surface of the paper substrate with a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 226 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Example 6]
50 parts of LBKP (50% of acacia wood, 50% of eucalyptus wood) and 50 parts of NBKP (50% of Douglas fir, 30% of radiata pine, 20% of cedar) as pulp raw materials were beaten using a double disc refiner, respectively, to obtain a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the paper making process, 4.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 4.0 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 374 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Example 7]
As a pulp raw material, 10 parts of LBKP (30% of acacia wood, 70% of eucalyptus wood) and 90 parts of NBKP (50% of Douglas fir, 30% of radiata pine, 20% of cedar) were beaten using a double disc refiner, respectively, to obtain a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 2.3 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 424 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Example 8]
As a pulp raw material, 10 parts of LBKP (20% of acacia wood, 80% of eucalyptus wood) and 90 parts of NBKP (50% of Douglas fir, 30% of radiata pine, 20% of cedar) were beaten using a double disc refiner, respectively, to obtain a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 2.3 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 453 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Comparative Example 1]
As a pulp raw material, 80 parts of LBKP (100% of acacia wood) and 20 parts of NBKP (50% of Douglas fir, 30% of radiata pine, 20% of cedar) were beaten using a double disc refiner to obtain a pulp slurry. With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a four-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 2.3 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 278 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Comparative example 2]
As a pulp raw material, 80 parts of LBKP (90% of acacia wood, 10% of eucalyptus wood) and 20 parts of NBKP (50% of Douglas fir, 30% of radiata pine, 20% of cedar) were beaten using a double disc refiner, respectively, to obtain a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 2.3 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 466 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Comparative Example 3]
50 parts LBKP (acacia wood 85%, eucalyptus wood 15%) and NBKP 50 parts (Douglas fir 50%, radiata pine 30%, cedar 20%) as pulp raw materials were beaten using a double disc refiner, respectively, to obtain a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, paper was made using a four-layer fourdrinier paper machine. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 2.3 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 119 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Comparative Example 4]
50 parts of LBKP (15% of acacia wood, 85% of eucalyptus wood) and 50 parts of NBKP (50% Douglas fir, 30% radiata pine, 20% cedar) as pulp raw materials were beaten using a double disc refiner to produce a pulp slurry. Got With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 2.3 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 377 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Comparative Example 5]
As a pulp raw material, 100 parts of NBKP (Douglas fir 50%, radiata pine 30%, cedar 20%) was beaten using a double disc refiner to obtain a pulp slurry. With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 2.3 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 421 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

[Comparative Example 6]
As a pulp raw material, 100 parts of NBKP (Douglas fir 50%, radiata pine 30%, cedar 20%) was beaten using a double disc refiner to obtain a pulp slurry. With respect to 100 parts of the obtained pulp slurry, 0.60 parts of cationic starch (solid content conversion) as an internal paper strength enhancer and 0.30 part of alkyl ketene dimer sizing agent as solid addition size agent (solid content conversion) ), 0.20 part of sulfuric acid band (solid content conversion), and 0.10 parts by mass (solid content conversion) of a polyamide-amine epichlorohydrin-based wet paper strength agent as a wet paper strength agent. Prepared. Using this stock, a five-layer fourdrinier paper machine was used to make paper. During the papermaking process, 3.0 parts by mass (in terms of solid content) of potato starch was sprayed between the layers by interlayer spraying, and after 5 layers of papermaking, 2.3 g of oxidized starch was applied to the surface of the paper base material by a size press. /M ² (solid content conversion) was applied to obtain a paper base material having a basis weight of 514 g/m ² . The obtained paper substrate contained the linear fatty acid and linear alcohol shown in Table 1.
A gable-top type paper container was obtained in the same manner as in Example 1 except that the thermoplastic resin layer was laminated on the obtained paper base material so that the thickness and the weight were as shown in Table 1.

The following performance evaluation was performed on the laminated paper obtained as described above. The performance evaluation was judged to be acceptable when the smoothness of the laminated paper, the peelability of the laminated paper, and the degree of paper stains were ⊚, ○ or Δ. Regarding the adhesiveness of the laminated paper, it was judged to be acceptable when ◎ or ○. The evaluation results are as shown in Table 1.

(Smoothness of laminated paper)
The Oken type smoothness was measured according to JIS P8155:2010 for the laminated paper of the gable-top type paper containers obtained in Examples and Comparative Examples. When the Oken type smoothness was 250 seconds or more, it was evaluated as ⊚, when it was 200 seconds or more, it was evaluated as ◯, when 100 seconds or more was evaluated as Δ, and when it was less than 100 seconds, it was evaluated as x.

(Adhesiveness of laminated paper)
Regarding the laminated paper of the gable top type paper containers obtained in Examples and Comparative Examples, after laminating the thermoplastic resin layer, after storing for 1 month at 23° C. and 50% humidity control conditions, according to JIS K6854-3:1999, The adhesive strength between the thermoplastic resin layer and the paper substrate was measured. The width of the test piece was 25 mm, the length of the bonded portion was 150 mm, and the degree of peeling in a 100 mm region excluding 25 mm at both ends of the bonded portion was visually evaluated by ⊚, ◯, Δ, and x. No peeling was observed and sufficient adhesion was indicated by ⊚, peeling was observed only in a very small portion of the circle ○, peeling was observed in a very small portion of the peeling area, and the peeling range was wide, Δ, When peeling was observed at a plurality of places, it was evaluated as x.

(Peelability of laminated paper)
Regarding the laminated paper of the gable-top type paper containers obtained in Examples and Comparative Examples, after laminating the thermoplastic resin layer, the laminated paper was stored for 12 months at a humidity condition of 23° C. and 50%, and then cut into 5 cm square pieces, and JISP8220 was used. Using a standard disintegrator described in −1:2012, disintegration was performed with water at 23° C. for 1 minute. Collect the disintegrated paper piece after 1 minute, and if 80% or more of the disintegrated paper piece is applied to an area of 2.0 cm or more from the edge and peeling of the thermoplastic resin layer and the paper base material is observed, ◎, 1.5 cm When the peeling of 2.0 cm or less was observed, it was evaluated as O, when the peeling of 1.0 cm or more and 1.5 cm or less was evaluated as Δ, and when the peeling was 1.0 cm or less, it was evaluated as x.

(Amount of paper stain)
The frequency of occurrence of paper stains when the paper base materials obtained in Examples and Comparative Examples were made was evaluated by ⊚, ◯, Δ, and x. The number of dust particles of 0.05 mm ² or more in an area corresponding to 100 g of the obtained paper base material was measured. If the number of dust particles was 0, it was ⊚; If it is 5 or more, it is marked with x.

As can be seen from the results in Table 1, the laminated papers of Examples 1 to 8 were all excellent in the smoothness of the base paper, the adhesiveness of the laminated paper, the peelability of the laminated paper, and the degree of paper stain. .. The laminated papers of Comparative Examples 1 to 6 were inferior in any of the smoothness of the base paper, the adhesiveness of the laminated paper, the releasability of the laminated paper, and the degree of paper stain.

Claims (12)

A laminated paper for a paper container having a paper base material mainly composed of cellulose pulp, and a thermoplastic resin layer laminated on at least one surface of the paper base material,
The paper substrate contains at least one of a linear fatty acid and a linear alcohol,
The linear fatty acid and the linear alcohol have a melting point of 80 to 100° C.,
A laminated paper for a paper container, wherein the total content of the linear fatty acid and the linear alcohol in the paper substrate is 100 to 2500 ppm. The laminated paper for a paper container according to claim 1, wherein the linear fatty acid has 24, 26 or 28 carbon atoms, and the linear alcohol has 26 or 28 carbon atoms. The paper substrate contains both the linear fatty acid and the linear alcohol,
The laminated paper for paper containers according to claim 1 or 2, wherein a ratio of the content of the linear alcohol to the content of the linear fatty acid is 3.0 to 33.3%. The laminated paper for a paper container according to any one of claims 1 to 3, wherein the fiber roughness of the disaggregation raw material of the paper substrate measured by Kajaani Fiber Lab is 0.020 to 0.18 mg/m. The laminated paper for paper containers according to any one of claims 1 to 4, which has a basis weight of 150 to 500 g/m ² . The laminated paper for a paper container according to any one of claims 1 to 5, wherein the paper base material is a multi-layered paper. A laminated paper paper base material for a paper container containing cellulose pulp as a main component,
Contains at least one of a straight chain fatty acid and a straight chain alcohol,
The linear fatty acid and the linear alcohol have a melting point of 80 to 100° C.,
A laminated paper paper base material for paper containers, wherein the total content of the linear fatty acid and the linear alcohol is 100 to 2500 ppm. The laminated paper paper base material for a paper container according to claim 7, which is a multi-layered paper. Paper container with laminated paper for paper container according to any one of claims 1-5. The paper container according to claim 9, which is for a liquid. A method for manufacturing a laminated paper for a paper container according to any one of claims 1 to 6, comprising:
A paper-making process of a paper base material whose main component is cellulose pulp,
A laminating step of laminating a thermoplastic resin layer on at least one surface of the paper substrate,
A method for producing a laminated paper for a paper container, which comprises bringing a material heated to 100° C. or higher into contact with the paper base material in at least one of the paper making step and the laminating step. 12. The laminated paper for a paper container according to claim 11, wherein the paper substrate is a multi-layered paper, and the paper substrate is paper-made by using a multi-layer paper machine in the paper making step. Method.