JP2001098497A - Base paper for liquid container made of paper and liquid container made of paper using the same - Google Patents

Abstract

(57) Abstract: The present invention relates to a paper-made liquid container used for a large-sized liquid paper container made of a paper-laminated material, and does not cause blistering and buckling during transportation. The present invention provides a paper-made liquid container base paper capable of preventing liquid leakage and the like, and a paper-made liquid container using the same. SOLUTION: In a base paper for a liquid container made of paper constituted by forming a plurality of pulp layers into multiple layers, the number of laminated layers is 3 or more, and the overall density is 0.50 to 0.70 g / cm.
³ , and the density of at least one outermost layer is 0.70 to 0.70.
0.90 g / cm ³ , and the middle layer is mainly composed of pulp selected from at least one of mechanical pulp, curled fiber, and mercerized pulp, and has a density of 0.20 to 0.60 g / cm ^3. Base paper for liquid containers made of paper. A base paper for a liquid container made of paper, in which at least one surface of the container is covered with a polyolefin resin film. A paper liquid container using the base paper for a paper liquid container, wherein the shape of the container is any of a roof type, a cup type, a cylindrical type, a brick type, and a regular tetrahedron type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention specifically relates to the storage of seasonings, fats and oils, liquid detergents, various beverages, etc.
This paper relates to paper-made liquid containers used for large-size paper-laminated liquid paper containers.The base paper for paper-made liquid containers has high stiffness and does not cause blistering, thus causing buckling during transportation. And a paper liquid container using the same, which can prevent liquid leakage and the like.

[0002]

2. Description of the Related Art Plastic bottles are widely used as liquid containers. In recent years, paper-based liquid containers have been used for sake, lactic acid drinks and juice drinks in consideration of environmental problems, recycling problems and resource saving. It is used. A typical example is a rectangular parallelepiped with a gable roof on the top, a flat on the top, or a cup or a cylinder on the top. Liquid paper containers made of paper are widely used in these applications. Recently, large-sized containers having a capacity of 1.8 liters or more and containing seasonings, fats and oils, liquid detergents, and the like are used. A liquid paper container made of paper is used. These liquid containers are mainly made of paper made of bleached pulp (white pulp), laminated with a thermoplastic resin represented by polyethylene, or laminated with aluminum foil as the base material. Is heat sealed to form a paper liquid container.

However, in the above-mentioned recent large-sized liquid paper container made of a paper laminated material, the weight of the stored contents causes bulging or buckling of the container, thereby deteriorating the shape retention of the liquid paper container. There is not enough problem, especially buckling that occurs in large-sized paper liquid paper containers (a phenomenon that causes deformation in the horizontal direction when the pressure applied to the thin plate etc. reaches a certain limit value in the vertical direction) For), repeated buckling due to vibration and shock during distribution and sales may cause tears in the paper laminate material or peeling of the heat-sealed part, causing liquid leakage in the liquid paper container. There was a disadvantage.

Further, there has been a movement to reduce the amount of refuse due to recent changes in environmental problems and simplification of containers and packaging.
In particular, the Containers and Packaging Recycling Law is enacted for paper containers, paper packaging, paper containers, and the like, and users are obliged to recycle or outsource recycling according to the amount of use. Therefore, in order to reduce the usage of paper containers, paper packaging, paper containers, etc., the direction of weight reduction, volume reduction, or packaging saving,
It is thought to go further. Reducing the weight of various packaging containers is required not only for the problem of garbage, but also as a measure against global warming. In the case where paperboard is used as a packaging material for paper containers, it has recently been required to minimize the environmental load. In particular, in the issue of global warming associated with the release of carbon dioxide, its use should be minimized because the wood, which is the starting material for pulp, fixes carbon dioxide. Therefore, double packaging has been abolished or the packaging itself has been omitted for the purpose of resource saving packaging. However, protection of contents is the purpose of packaging, and its reliability is significantly improved. In that sense, it is desired to use a lightweight base paper for a liquid container made of paper with a low environmental load.

[0005] However, the paper currently used as the base paper for the paper liquid container is a paperboard having a size of about 350 g / m ² per square meter.
If the rice tsubo is reduced to reduce the weight, even if the above-mentioned buckling does not occur, the barrel portion swells due to the weight of the liquid when the liquid is filled, causing a blistering phenomenon. For this reason, if the capacity of the liquid container is about 500 cc, this does not cause much problem. However, when targeting a liquid having a capacity of about 1000 cc or more, it is not possible to use a base paper having a low U.S. meter. Particularly, in recent years, those having a capacity of 1500 cc or more have come out, and there has been a demand for a base paper for preventing blistering in a high-capacity liquid container.

[0006] The simplest countermeasures against buckling and blistering are to increase the rice tsubo, but since it is required to reduce the weight of the container, it is difficult to easily increase the weight. Therefore, in order to solve these problems, as disclosed in US Pat. No. 3,232,516 (Paperboard Container) and Japanese Utility Model Publication No. 60-40409 (liquid paper container), four sheets of liquid paper containers are used. An invention and a device are disclosed in which a plurality of horizontal pressing ruled lines are provided on a side plate from left and right sides to a central portion thereof. However, large-sized paper having a gable roof-shaped rectangular parallelepiped top surface or a flat rectangular flat top surface shape and containing 1.8 liters or more, especially containing hot-filled seasonings and oils and fats. In a liquid paper container made of a laminated material, the rigidity is reduced due to the heating of the paper laminated material, and the inside of the liquid paper container is swollen and buckled due to cooling of the contents and decompression of the inside. However, tearing of the paper laminate material, peeling of the heat-sealed portion and the like cannot be prevented, and it is impossible to prevent liquid leakage from the liquid paper container.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a paper-made liquid container used for a large-sized liquid paper container made of a paper-laminated material. The present invention provides a paper-made liquid container base paper capable of preventing liquid leakage and the like, and a paper-made liquid container using the same.

[0008]

The present invention adopts the following constitution. 1. In a base paper for a liquid container made of paper constituted by forming a plurality of pulp layers into multiple layers, the number of laminated layers is 3 or more, and the overall density is 0.50 to 0.70 g / cm ³ , and at least The density of one outermost layer is 0.70 to 0.9
0 g / cm ³ , and the middle layer is mainly composed of pulp selected from at least one of mechanical pulp, curled fiber, and mercerized pulp, and has a density of 0.20 to 0.60 g / cm ³ . A base paper for a liquid container made of paper. 2. 2. The base paper for a liquid container for paper according to 1, wherein at least one surface of the container is covered with a polyolefin resin film. 3. 3. A paper liquid container using the base paper for a paper liquid container according to 1 or 2, wherein the container has a roof shape. 4. 3. A paper-made liquid container using the base paper for a paper-made liquid container according to 1 or 2, wherein the container has a cup shape. 5. 3. A paper liquid container using the base paper for a paper liquid container according to 1 or 2, wherein the container has a cylindrical shape. 6. 3. A paper-made liquid container using the base paper for a paper-made liquid container according to 1 or 2, wherein the shape of the container is a brick type. 7. 3. A paper liquid container using the base paper for a paper liquid container according to 1 or 2, wherein the container has a regular tetrahedral shape.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The base paper for a liquid container obtained by the present invention is obtained by drying a multi-layered sheet made from a plurality of wire parts of a paper machine in order to exhibit rigidity as a paperboard. It is a bulky paperboard having three or more layers and having a density of the entire finished paperboard of 0.50 to 0.70 g / cm ³ . In order to obtain a bulky and highly rigid paperboard at this density, the middle layer has a density of 0.20 to 0.60 g / cm.
³ and formed as a layer to obtain a bulk, the density of the paper layer formed as an outer layer in contact with the middle layer is 0.70 to 0.70
By making it as high as 0.90 g / cm ³ , the lowering of the Young's modulus of the low-density layer formed in the middle layer is complemented by adding the outer high-density layer, and a sandwich structure is formed by forming a sandwich structure. A liquid container base paper can be obtained. As shown by these sandwich structures,
The outer layer is a layer located outside the middle layer and substantially in contact with the middle layer or located outside through another layer, and refers to a layer existing in the outermost layer. These sandwich structures only need to be configured to complement the low-density middle layer with a higher-density outer layer, that is, all layers except the low-density middle layer are outer layers.

[0010] When the stiffness S of the sheet considering the sheet and the cantilever, S = E · I / B · W = E · T 3/12 · W,
(E: Young's modulus MPa, I: Second moment of area N · c
m ² , B: sample width mm, W: sample weight kg, T: sample thickness mm), and stiffness S is 3 of Young's modulus and sheet thickness.
It can be considered proportional to the power.

Further, the stiffness of a sheet having a laminated structure such as paperboard is described in Tappi Nov, 1963, Vol. 46,
No. 11A. T. According to Luey, similarly, the stiffness value of each layer is obtained from the Young's modulus of each layer and the moment of inertia of each layer using the above-described formula, and the stiffness value of all layers is obtained by the sum of the stiffness values of each layer. I have. Based on this concept, the stiffness increases as the distance from the center of the paper thickness increases, that is, as the paper thickness increases, so that the middle layer may be made bulky. Also, since the stiffness is represented by the product of the cube of the thickness and the Young's modulus, the higher the Young's modulus of the outer layer, the more effective the stiffness is.

For this reason, the density of the middle layer is 0.2 to 0.1.
6 g / cm ³ . If it is less than 0.2 g / cm ³ , the interlaminar strength is greatly reduced, and if it exceeds 0.6 g / cm ³ , it is not possible to obtain the desired density of the bulky paperboard. More preferably, the density of the middle layer is 0.3 to 0.5 g.
/ Cm ³ . The density of the paper layer formed on the outer layer is 0.7
Is a ~0.9g / cm ^3. If it is less than 0.7 g / cm ³ , the Young's modulus is reduced, and improvement in rigidity cannot be expected.
On the other hand, a higher density of the outer layer is better in terms of improving Young's modulus, but at present it is practically difficult to obtain a density exceeding 0.9 g / cm ³ at the papermaking stage.

As described above, in order to improve the rigidity, it is preferable to form an outer layer on either side of the middle layer and further increase the Young's modulus of the outer layer. However, only one surface of the outer layer has a high density and a high Young's modulus. A method is also possible in which an outer layer is provided and the density of the outer layer alone is prevented from increasing by increasing the density of the outer layer. According to this method, the operability can be improved while the rigidity and the Young's modulus are balanced without increasing the density and the Young's modulus on the other surface and without reducing the overall thickness. However, the degree of improvement in rigidity of each outer layer is smaller than when the density and Young's modulus are increased.

There is no particular limitation on the pulp used to increase the density used for the outer layer, and any type of pulp may be selected. However, the degree of beating of N-material (coniferous) pulp such as NUKP and NBKP is increased. And do not lose rigidity. In order to make these sandwich structures effective, the basis weight of the outermost layer is preferably 15 to 100 g / m ² . That is, if it is less than 15 g / m ² , papermaking cannot be performed, or even if it can be performed, the effect of expressing a high Young's modulus is small. On the other hand, if it exceeds 100 g / m ² , the basis weight of the middle layer is relatively reduced, and it is difficult to form a bulky structure.

As a method for producing paperboard, generally, several tens of g / m are provided on a plurality of wire parts of about 10 stations.
^The pulp slurry corresponding to the dried rice tsubo of No. ² is developed to form a wet sheet. For example, first, a pulp layer of about 40 g / m ² is formed on the wire part forming the outer layer located at the outermost layer, dehydrated, and then transferred to a blanket. Next, a paper layer is similarly formed with another wire part for the middle layer, and the outermost layer on a blanket is overlapped to form two layers. Repeat the method of superimposing these two layers on the paper layer formed by another wire part, and finally form the other outermost layer,
A multilayer paperboard of about 10 layers in total is obtained.

On the other hand, if the Canadian standard freeness of the pulp used for the middle layer is less than 200 ml in the re-disintegrated state, drainage after paper making is poor, paper making and water squeezing are performed, and thus pulp fibers are sucked and deposited, and the pulp fiber becomes bulky after paper making Contrary to the reduction in density, a dense structure is likely to be formed. Therefore, it is not advantageous because it becomes difficult to form a desired bulky structure. If it exceeds 650 ml, the density may be too low and balloon-like blisters may easily occur. Furthermore, these JIS-P-
Redispersing and measuring the pulp used according to the Canadian standard form of 8121 is effective for grasping the necessary pulp characteristics in a single time using a product showing good operability. A stock having a freeness of 200 to 650 ml in a defiberization state is a Canadian standard freeness of 2 in a mixed stock state, regardless of the type of pulp used therein.
The volume may be 50 to 700 ml.

The base paper for a liquid container made of paper of the present invention may be basically composed of a low-density middle layer and a high-density outer layer. Good printability can be obtained by forming a coating layer containing an adhesive and a pigment. SB for adhesive
Known substances such as R latex, starch, casein, polyvinyl alcohol and the like can be used. The coating amount is about 1.0 to 10.0 g / m ^{2 as a} whole, and these can be formed as a single layer, or two or more layers. Pigments used in the coating layer include calcium carbonate, kaolin clay, talc, titanium oxide, plastic pigment, and the like, and known adhesives such as SBR latex, starch, casein, and polyvinyl alcohol are used. it can. The coating amount is 20
A to 30 g / m ² approximately, these single-layer or two
It can be formed in layers or more. Although this adhesive layer and the coating layer can be formed directly on the pulp layer constituting the middle layer, the obtained smoothness is often low and the printability is inferior, and the pulp layer having a high density is usually formed as the outer layer. A coating layer is formed thereon. Further, it is preferable that a layer which is an outer layer with respect to the intermediate layer immediately below the coating layer is a paper layer which is smoothed by increasing the degree of beating.

The pulp used for the middle layer may be a chemical pulp or a pulp obtained by imparting a low-density characteristic to a finished pulp such as mercerized pulp or curled fiber in order to maintain its low density by chemical treatment. And TMP,
There are mechanical pulp such as CTMP and mechanical pulp partially chemically treated, but mercerized pulp and curled fiber are expensive or their supply is limited,
It is better to limit it to a special case when used alone. Mechanical pulp is most preferred. Further, in mechanical pulp, generally, N material is simply crushed by mechanical force and then defibrated, and there are GP, TMP, RGP and the like.
RGP is preferred. Among them, those obtained from wood such as radiata pine, southern pine, Douglas fir,
When a paper layer is formed, the fiber is rigid and hardly deformed, the density tends to be low, and the reduction in density during pressing is small, which is particularly preferable. The present invention also includes a method of adding a chemical during mechanical crushing and a pulp that undergoes a step of bleaching after pulping. The point is that the density of the middle layer is
Various pulp such as mechanical pulp, curled fiber, mercerized pulp and the like are selected so as to obtain 0.6 g / cm ^3, and if necessary, mixed and used.

If necessary, a filler for general papermaking, a sizing agent, a retention aid, a paper strength enhancer, etc. may be added to the stock as long as the quality of the base paper for a liquid container made of paper of the present invention is not impaired. Can be added. The pH at the time of papermaking is also 4.
The range can be from about 5 to about 6 to 8 for neutral papermaking. In addition, coating can be performed by installing various coaters. What is sprayed on the surface or in the middle of paper or what is added by filling is polyvinyl alcohol, latex, alkyl ketene dimer system, maleic anhydride system, styrene acrylic acid system, styrene acrylic system, etc. various sizing agents, pigments, dyes Can be applied or impregnated. Generally, the paper machine may be any machine that can make a multi-layer, and a paper machine such as a circular net multi-layer or a long net multi-layer can be used as appropriate.

The inner surface of the paper container, or both surfaces,
It is necessary to form a water-resistant coating by applying, internally adding, vapor-depositing, laminating, etc. to prevent liquid infiltration and liquid leakage. When a paper container is loaded after the contents have been filled in advance, the water-resistant coating may or may not be present. The method of filling the contents in the bag and protecting it with a paper container as in this case has an advantage that the paper container can be recycled.

The internal additive for forming the water-resistant coating or the chemical to be applied and the treatment method thereof can use the various sizing agents as described above and can be freely selected. As another surface treatment method, a method such as lamination or vapor deposition may be employed. The resin to be laminated is not particularly limited,
What is necessary is just to cover with a polyolefin type, a polypropylene type, a PET type resin, etc.

The base paper for the liquid container for paper of the present invention has a rice tsubo of 90%.
６００600 g / m ² . The film to be laminated is usually about 10 to 50 μm, but is not limited to this.

[0023]

The present invention will be described in more detail with reference to the following Examples, which by no means limit the scope of the present invention. Unless otherwise specified, numerical values indicating the concentration, compounding amount, applied amount, etc. are numerical values based on the weight of the solid component or the active ingredient.

Example 1 The following three types of pulp were beaten using a pulp beater manufactured by Kumagaya Riki Kogyo at a wire speed of 300 m / min using an oriented paper machine manufactured by Kumagaya Riki Kogyo. Paper making and paper making are performed sequentially. At the time of mixing, the starch ONL510 of Oji cornstarch was sprayed onto the front side (felt side) of each layer with a starch concentration of 2.0% by spray spraying so that the solid component adhesion amount was 1.0 g / m ² . Combine. Commercially available NBKP, 45
0mlcsf, 50g / m ^2, Radiata pine TM
P350mlcsf, 180g / m ² , commercially available NBKP
450mlcsf, 50g / m ^2. Furthermore, the nip pressure is controlled to 10 kg by controlling the air pressure of the calender of the Yuri roll machine.
/ Cm, and a wet paper-like sheet made at a speed of 30 m / min is sandwiched between monoplastic canvas sheets made by Shikishima Canvas and subjected to pressure treatment. Thereafter, drying is performed using a ferro-type cylindrical heating dryer type dryer.
After that, the humidity was adjusted at 20 ° C. and 65% RH, and the nip pressure was set to 20 kg / cm by a calender of a Yuri roll machine, and calendered at a speed of 20 m / min.
Further, by hand coating, a 8.0% PVA (Kuraray:
2.0 g / m ^{2 of} Kuraray Povar PVA-KL118)
Coating and calendering at 120 ° C. at a speed of 20 m / min with a nip pressure of 40 kg / cm using a calender of a Yuri roll machine to produce samples, and these samples are used as base paper for liquid containers made of paper. did. Then 20 ℃
Adjust the humidity at 65% RH and measure the grammage, thickness, density and Z strength Taber stiffness. Furthermore, polyethylene was melt-extruded on both sides of the base paper for a liquid container made of paper to have a thickness of 40 μm and laminated to form a blank sheet for a liquid container made of paper. The blank sheet was punched into a roof-type mold to have a content of 1.8. Six roof-type liquid paper containers as shown in FIG. 1 were prepared and filled with water. After confirming that the appearance after filling is in a normal form without a blister, the container is densely housed in a normal packing cardboard box having an inner size of 28 × 42 × 24 cm, and is packed with a truck. Conduct a transportation test in the suburbs for time and observe the degree of blistering of the outer appearance of the container. The degree of trunk swelling was determined by the method described below. These results are shown in Table 1.
It was shown to. (same as below.)

Example 2 In the treatment and blending of the pulp used in Example 1, commercially available NBKP, 450 mlcsf, 50 g / m ² , radiatapine TMP 300 mlcsf / commercial NBKP,
150mlcsf article = 70/30 280mlcsf freeness after compounding with, 250g / m ^2, commercially available NBKP
At the time of mixing, the mixture is 450 mlcsf, 50 g / m ² , and the starch is sprayed onto the front side (felt side) of each layer without spraying. In other respects, a sample was prepared in the same manner as in Example 1, and after measuring the paper quality, a roof-type liquid container was prepared, filled with water and a body swelling evaluation test was performed as in Example 1.

Example 3 In the treatment and blending of the pulp used in Example 1, commercially available NBKP, 450 mlcsf, 50 g / m ² , radiata pine TMP 350 mlcsf / commercial LBKP,
350Mlcsf article = 70/30 350mlcsf freeness after compounding with, 200g / m ^2, commercially available NBKP
A sample was prepared in the same manner as in Example 1 except that the sample was 380 mlcsf and 50 g / m ² , and after measuring the paper quality, a roof-type liquid container was prepared and filled with water and a body swelling evaluation test was performed in the same manner as in Example 1. .

Example 4 In the treatment and blending of the pulp used in Example 1, commercial NBKP, 450 mlcsf, 50 g / m ² , commercial mercerized pulp 300 mlcsf / commercial NBKP,
50 mlcsf product = 70/30, freeness after blending is 250 mlcsf, 200 g / m ² , commercial NBKP4
A sample was prepared and the paper quality was measured in the same manner as in Example 1 except that 50 mlcsf and 50 g / m ² were used. In other respects, a sample was prepared in the same manner as in Example 1, and after measuring the paper quality, a roof-type liquid container was prepared, filled with water and a body swelling evaluation test was performed as in Example 1.

Example 5 In the treatment and blending of the pulp used in Example 1, after blending with commercially available NBKP, 450 mlcsf, 50 g / m ² , commercial NBKP, 150 mlcsff product / 750 mlcsf product from Warehauser = 70/30 Freeness of 300mlcsf, 160g / m ² ,
A sample was prepared in the same manner as in Example 1 except that the commercially available NBKP was 450 mlcsf, 40 g / m ² , the paper quality was measured, a roof-type liquid container was prepared, and water was filled and a body swelling evaluation test was performed in the same manner as in Example 1. did.

Example 6 The procedure of Example 1 was repeated except that a sample was prepared in the same manner as in Example 1, mixed with pulp treatment, the paper quality was measured, and a cup-shaped liquid container as shown in FIG. Water filling was carried out in the same manner as in Example 1 to perform a trunk swelling evaluation test.

Example 7 The procedure of Example 5 was repeated except that a sample was prepared in the same manner as in Example 5, mixed with pulp treatment, the paper quality was measured, and a cylindrical liquid container as shown in FIG. Water filling was carried out in the same manner as in No. 5 to carry out a trunk swelling evaluation test.

Example 8 In the treatment and blending of the pulp used in Example 1, the basis weight of each layer was 50 g / m ² 150 g / m ² 50 g / m ²
A sample was prepared in the same manner as in Example 1 except that the sample was prepared, and the paper quality was measured in the same manner as in Example 1 except that the container was changed to the brick type shown in FIG.

COMPARATIVE EXAMPLE 1 In the same manner as in Example 1, the amount of the pulp in the back layer was set to 0, and only the surface layer was constituted.
addition to those papermaking in the same manner as in Example 1 and sample preparation as m ^2, and then paper quality measurements.

Comparative Example 2 The composition of the back layer used in Example 1 was 0 except that the blending amount of the pulp was 0, and only the surface layer and the middle layer were used. The surface layer was 50 g / m ^{2 and the} middle layer was 250 g / m ^2. A sample was prepared in the same manner as in Example 1, and the paper quality was measured.

Comparative Example 3 Samples were prepared in the same manner as in Example 1 except that the pulp used in Example 1 was mixed in the same manner, and each had a three-layer structure having a basis weight of 28 g / m ² . Paper quality was measured.

Comparative Example 4 In the treatment and blending of the pulp used in Example 2, the basis weight of each layer was 100 g / m ² 450 g / m ² 100 g /
A sample was prepared in the same manner as in Example 2 except that m ^{2 was used,} and the paper quality was measured.

Comparative Example 5 In the treatment and blending of the pulp used in Comparative Example 4, each layer
100g / m ^Two450g / m^Two100g /
m^TwoA sample was prepared in the same manner as in Comparative Example 4 except that
It was measured.

Comparative Example 6 A paper was prepared in the same manner as in Comparative Example 1 to prepare a sample, and the paper quality was measured in the same manner as in Comparative Example 1 except that the shape of the container was changed to the cup type shown in FIG.

Comparative Example 7 In the treatment and blending of the pulp used in Comparative Example 4, the basis weight of each layer was changed to 50 g / m ² 150 g / m ² 50 g / m ²
A sample was prepared in the same manner as in Comparative Example 4 except that the sample was prepared, and the paper quality was measured in the same manner as in Comparative Example 4 except that the container was changed to the brick type shown in FIG.

Tables 1 and 2 show the paper quality and container evaluation results of each sample obtained as described above. The following evaluation method was used. [Density of outer layer, middle layer, back layer, each layer] JIS-P-813
9, each layer and the interlayer were peeled off by the interlayer peeling method described in the peeling strength test method of the laminated layer of the paperboard, and the thickness (mm), basis weight (g / g)
m ² ). The thickness of each peeled layer is fluffed by peeling and becomes thicker than the actual thickness, so calculate the correction factor value by the following method, correct the thickness value of each layer after peeling, and Calculate the density. Correction factor value = total layer thickness before peeling / total value of each layer thickness after peeling The peeling method of the peeling strength of the laminated layer of the paperboard according to JIS-P-8139 is described in the above JIS-P-8139. When it is difficult, the sample of the multilayered assembling sheet is immersed in warm water of 60 ° C. for 1 hour, and then separated into a surface layer, a middle layer and a back layer. Each of the stripped layers is dried to obtain a thickness (mm) and a basis weight (g / m ² ). Thereafter, the above correction factor value is similarly calculated, the thickness of each of the separated layers is corrected, and the density of each of the layers is calculated. [Stiffness] According to JIS P 8125.

[Judgment of trunk swelling degree] The outer peripheral value of the central part of the trunk was measured, and the difference between the normal state before the transport test and the peripheral value of the central part of the trunk after the transport test was measured.
未 満 for less than m. Those with 1.5 mm or more were evaluated as x, and those with 3.0 mm or more were evaluated as xx.

[Comprehensive Judgment] If the body blister judgment is x, x
When the base paper used was 500 g / m ² or more, the cost was high, and the result was x.

[0042]

[Table 1]

[0043]

[Table 2]

[Composition of paint] Top coat: kaolin (Ultra White 90 manufactured by Engelhard Co.) / Calcium carbonate (Brilliant 15 manufactured by Shiraishi Kogyo) / titanium oxide (TCA3 manufactured by Tochem Products)
33) = 50/35/15 and latex (L1410 manufactured by Asahi Kasei Corporation) / urea phosphorylated starch (MS4600 manufactured by Nippon Shokuhin Kako Co., Ltd.) = 15/5. (The blending number based on the solid content weight, the same applies hereinafter.) Undercoat: kaolin (Caobrite manufactured by Seal Co.) / Calcium carbonate (Softon 2200 manufactured by Bihoku Powder Chemical Co., Ltd.) = 50/5
0 and latex (0668 manufactured by JSR) / urea phosphorylated ester (MS4600 manufactured by Nippon Shokuhin Kako)
= 15/5.

[0045]

When the paperboard is manufactured by the method according to the present invention, as shown in Table 1, there is no problem in operation and compared with the paperboard manufactured mainly from waste paper,
It is possible to produce bulky, low-density, high-rigidity, and stiff paper. For this reason, compared to conventional paperboard, it is possible to greatly reduce the basis weight to obtain the same rigidity, and to greatly reduce the weight of the material in paper containers, packaging materials, laminates and molded products using paperboard, It is also effective in terms of resource protection.

[Brief description of the drawings]

FIG. 1 is a schematic external view of a roof type container.

FIG. 2 is a schematic external view of a cylindrical container.

FIG. 3 is a schematic external view of a cup-shaped container.

FIG. 4 is a schematic external view of a brick type container.

FIG. 5 is a schematic external view of a regular tetrahedral container.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E060 AA03 AA05 AB05 BC01 BC04 DA21 EA03 4F100 AJ02A AK03B AK03C AK04 BA02 BA03 BA06 BA10B BA10C DG10A GB16 GB23 JA13A JL03 4L055 AC01 AF09 AF10 AF46 AJ01 FA12 FA18

Claims (3)

[Claims] 1. A base paper for a liquid container made of paper comprising a plurality of pulp layers in a multilayer structure, wherein the number of laminated layers is three or more, and the overall density is 0.50 to 0.70 g / cm.
³ , and the density of at least one outermost layer is 0.70 to 0.70.
0.90 g / cm ³ , and the middle layer is mainly composed of pulp selected from at least one of mechanical pulp, curled fiber, and mercerized pulp, and has a density of 0.20 to 0.60 g / cm ^3. A base paper for a liquid container made of paper, characterized in that: 2. The container according to claim 1, wherein at least one surface of the container is covered with a polyolefin resin film.
The base paper for a paper liquid container according to the above. 3. The container has a roof shape, a cup shape, a cylindrical shape,
3. A paper-made liquid container using the base paper for a paper-made liquid container according to claim 1 or 2, which is of a brick type or a regular tetrahedron type.