JP4792071B2 - Cardboard sheet - Google Patents

Description

The present invention relates to a corrugated sheet, and more particularly, the outer liner, corrugating medium constituting the corrugated cardboard sheet, and all of the interior liner, defibration properties, excellent solubility, paper or paperboard can be easily reproduced dissolution process The present invention relates to the corrugated cardboard sheet used .

  A general corrugated cardboard sheet is usually composed of an outer liner, a core base paper, and an inner liner. When manufacturing the corrugated cardboard sheet, the outer liner is classified according to the use of the corrugated cardboard case formed using the corrugated cardboard sheet. Each of the core base paper and the interior liner is selected and used. For this reason, inventory management of each base paper has become complicated, and in recent years, there has been an increasing demand for a combination paper that can be used as any of an exterior liner, a core base paper, and an interior liner.

  In addition, confidential documents such as important documents and confidential documents that are no longer needed in government offices, offices, etc. (hereinafter referred to as “confidential waste paper”) are collected, and when these are discarded, a large amount of documents are shredded. It is very time-consuming. For this reason, many offices outsource the disposal of these documents to specialized processors.

  In this case, both the waste disposal company and the delivery company have established a thorough information processing system in order to immediately dissolve and incinerate the confidential waste paper that is the waste document carried by the delivery company to the disposal facility. Various measures have been taken to prevent the information described in the document from leaking, for example, to prevent third parties from entering the document transportation route. As a packaging container (container) at that time, a cardboard case, cloth, or a collection bag made of an opaque synthetic resin material is generally used. Then, the confidential waste paper is melted while being packaged, and the confidential waste paper is effectively reused as waste paper. However, a collection bag made of a synthetic resin material is suitable for incineration, but it cannot be dissolved as it is. Further, in the case of a cardboard case, it can be dissolved as it is, but the cardboard case is manufactured with a cardboard sheet formed using a base paper that is recycled from low whiteness waste paper. For this reason, high-quality paper and PPC paper used for documents at offices are reused mainly for high-quality and medium-grade paper, as well as used flyer paper, white paper, and colored paper. In general, however, the disaggregated pulp that has been disaggregated together with the corrugated cardboard sheet is processed as a raw material (WP) for corrugated cardboard, and the confidential used paper, which is a high quality used paper, cannot be used effectively. Further, the disaggregation property of the corrugated base paper such as the liner and the core used in the general corrugated cardboard sheet is inferior to the easy disaggregation property as compared with the confidential waste paper which is the above-mentioned used waste paper. For this reason, when the above-mentioned waste paper is mixed and dissolved and disaggregated, there is also a problem that the pulp fiber of the old waste paper is excessively damaged.

  As a base paper of such a corrugated cardboard sheet, a paper tube base paper that forms a paper tube used as a core rod around which things such as white paperboard, a core for household wrap and a core for adhesive tape are wound may be used. In addition, as this paper tube base paper, paper such as kraft paper, as well as exterior liners, interior liners, and core raw papers used for corrugated cardboard sheets, are selected according to the use of the paper tube. . However, when white paperboard or paper tube base paper is used as a base paper for corrugated cardboard sheets, there is a problem that the processing suitability with a corrugator and the box making ability (cracking with a flap) are poor. Furthermore, when used as a container for confidential used paper, the used waste paper is collected, unpacked while being stored, and has a problem of solubility and disaggregation in a process of dissolving for the purpose of reuse. Therefore, it has been considered and proposed to use various papers shown below as papers used for corrugated cardboard sheets used for storage containers when transporting confidential used paper.

  First, Patent Document 1 discloses a coated white ball in which a lot of used paper that is not subjected to deinking treatment is mixed in the back layer and a pigment is applied on the back surface. This coated white ball has improved ink color development at the time of printing on the back surface, is excellent in printability for surface printing, and is excellent in resistance to ruled line cracking. However, according to this coated white ball, a lot of used paper that does not undergo deinking treatment is blended in the back layer, so even if there is no problem in printability, a corrugated cardboard case using these as base paper is used as a raw paper raw material. When used, the back layer contains a lot of waste paper that does not undergo deinking treatment, so the whiteness of the recycled pulp is low, and the waste paper material used for high and medium grades is low white. There is a problem of dust, dust, etc., which causes quality to deteriorate. Further, the cardboard case composed of such coated white balls also has a problem of solubility and disaggregation when it is dissolved for the purpose of reuse with the confidential waste paper packed.

  Patent Document 2 discloses a method for producing a paperboard having excellent resistance to ruled line cracking by adding a predetermined amphoteric surfactant to a pulp slurry. However, according to the paperboard manufactured by this manufacturing method, although the resistance to ruled line cracking is excellent, there is a problem that it is inferior in terms of tensile strength and compressive strength. In addition, the cardboard case made using the paperboard manufactured by the manufacturing method described in Patent Document 2 also has problems of solubility and disaggregation. It was difficult to carry out dissolution treatment for the purpose of reuse.

  Patent Document 3 discloses a low-density coated paperboard having a predetermined range of density, print surface roughness, air permeability, and the like. This paperboard is said to be excellent in gravure printing suitability and ruled line cracking suitability. However, according to this paperboard, since the pigment coating layer is provided on the surface layer, in the case of a severe cardboard construction, there is a problem that ruled cracks are likely to occur at the flap portion. In addition, when recycled as waste paper pulp, there is a problem that the coating layer portion is difficult to dissolve and disaggregation is poor.

  Patent Document 4 discloses a corrugated cardboard sheet in which at least one liner is stretched paper. According to this corrugated cardboard sheet, it is said that occurrence of ruled line breakage can be prevented. However, according to this corrugated cardboard sheet, it has excellent resistance to crease resistance due to elongation, but this corrugated cardboard sheet also has problems of solubility and disaggregation. Therefore, it was difficult to carry out dissolution treatment for the purpose of reuse.

  That is, in the first place, the coated white balls and paperboards described in the above-mentioned Patent Documents 1 to 4 are unpacked while collecting and storing confidential waste paper when the assembled cardboard case is used as a container for confidential waste paper, The disaggregation property for dissolution treatment for reuse has not been studied.

  In addition, since there is a high possibility that high-quality waste paper pulp is obtained from high-quality waste paper, it is desirable that the storage container does not cause a decrease in whiteness when the entire storage container is dissolved. It is. However, in Patent Documents 1 to 4, even if there is a reference to whiteness, it is from the viewpoint of printability and not from the viewpoint of reuse. Moreover, about the paperboard etc. which are described in these patent documents 1-4, since it is used for the exterior liner and interior liner which comprise a corrugated cardboard case, when used as a core raw paper, it is a bonding and box making process. I have problems such as jumping.

  Further, the outer and inner liners of the corrugated cardboard sheet only have compression strength and burst strength, and the core base paper has only compression strength and tensile strength. These qualities are strength standards that are determined at a minimum only to ensure the case strength of the cardboard case. For this reason, in the manufacturing process of the corrugated cardboard sheet, the exterior liner, the interior liner, and the core base paper are individually selected depending on the use application of the box. In particular, the method of using the core base paper and the exterior liner / interior liner are greatly different, and the quality design is adapted to each application. That is, for example, if the strength as an exterior liner is secured, the paper becomes hard, and if such an exterior liner is used as a core raw paper, step cracking or jumping occurs when it is fed. Therefore, it was difficult to use the exterior liner as the core raw paper.

  In addition, when manufacturing cardboard cases, it is necessary to secure a base paper for each use of the exterior liner, interior liner, and core, and the management of inventory is complicated. There has also been a demand for the development of paper or paperboard that can be used.

JP 2000-192395 A Japanese Patent Laid-Open No. 2001-262496 JP 2002-105895 A JP 2001-105516 A

  The present invention has been made in view of the above circumstances, and the object of the present invention is to be used for all of the exterior liner, core base paper, and interior liner constituting the corrugated cardboard sheet. Containers that store confidential used paper made using sheets are excellent in easy dissolution and easy disaggregation, and can be dissolved or processed for reuse even in a state where the confidential used paper is unpacked while being packed. It is to provide a paperboard and this cardboard sheet.

The object of the present invention is a corrugated cardboard sheet comprising an exterior liner, a core base paper, and an interior liner, and the paper or paperboard is used for all of the exterior liner, the core base paper, and the interior liner. The paper or paperboard uses pulp having a whiteness of 75% or more based on JIS-P8141 as a raw material pulp, and is based on JIS-P8226 of disaggregated pulp disaggregated by a method based on JIS-P8220 (1998). , Measured according to ISO9416 (1998) of a sheet prepared according to JIS-P8222 (1998), having a weight average fiber length of 0.5 to 1.5 mm measured by Metso FiberLab The scattering coefficient is 35 to 80, and a coating liquid containing a water-soluble resin is applied to at least one surface, and JIS-P8 It is achieved by providing a corrugated cardboard sheet characterized in that the Denison wax value specified in 129 (1997) is 13A or more .

Further, the object of the present invention is to provide a corrugated cardboard wherein the paper or paperboard has an inorganic pigment content of less than 10% by mass and a paper density of 0.5 to 0.8 g / cm ^3. This is achieved more effectively by providing a sheet .

The above-described object of the present invention, the paper or paperboard, by providing a cardboard sheet coated amount of the coating liquid per side is characterized by a 0.1 to 10 g / m ^2, Achieved more effectively.

  According to the paper or paperboard according to the present invention, the weight average fiber length measured by Metso FiberLab of the disaggregated pulp disaggregated by a method according to JIS-P8220 (1998) is measured according to JIS-P8226. The scattering coefficient measured according to ISO9416 (1998) of the sheet prepared according to JIS-P8222 (1998) using this disaggregated pulp is adjusted to be 1.5 mm so as to be 35-80. Therefore, it is possible to obtain paper or paperboard having excellent easy disintegration and easy dissolution.

  Further, this paper or paperboard can be used for all of the exterior liner, core base paper, and interior liner constituting the corrugated cardboard sheet. Such a corrugated cardboard sheet can be used, for example, in an unopened state with confidential waste paper packed. Disaggregation processing can be performed.

Hereinafter, the paper or board according to the present invention will be described in detail.
The base paper of the paper or paperboard (hereinafter referred to as “main paper or paperboard”) according to the present invention has a whiteness based on JIS-P8141 (2001) of 75% or more, preferably 80% or more, and more preferably as a raw material. Of 85% or more of pulp and / or kraft pulp, measured based on the color chart by the C dyeing method according to the paper, paperboard and pulp-fiber composition test method specified in JIS-P8120 (1998). It is formed using a raw material pulp having a fiber content of 50% by mass or more, preferably 90 to 100% by mass. In addition, when the whiteness of the raw material pulp is 75% or more , as will be described later, when paper or paperboard is used for the cardboard case, the recovered waste paper is collected and stored, and when the entire cardboard case is dissolved, Whiteness that can be used as waste paper pulp to be blended with high-quality / medium-quality paper can be maintained.

  In the present paper or paperboard, the raw material pulp that is preferably used is virgin chemical pulp (hardwood bleached kraft pulp, softwood bleached kraft pulp, pulp obtained by chemically treating other fiber raw materials), particularly hardwood bleached kraft pulp, In addition, semi-chemical pulp that has been impregnated with chemicals after being soaked in wood or chip, then mechanically pulped to chemi-ground pulp, chemi-mechanical pulp and chips until slightly softened, and then pulped with a refiner, etc. Virgin pulp may be included.

  In addition to the above-mentioned raw pulp, high-quality paper, high-quality coated paper, medium-quality paper, medium-quality coated paper, reprinted paper, flat plate, letterpress, intaglio printing, electrophotographic method, heat-sensitive method, thermal transfer method, pressure-sensitive Recording paper, ink-jet recording system, waste paper printed with carbon paper, waste paper written with water-based, oil-based ink or pencil, waste paper such as newspaper waste paper, deinked pulp (DIP), paper sludge, paper mill wastewater Scum or the like can be used. In other words, the White Paper, Cream White, Ruled White, Card, White, Medium White, White Manila, Imitation, Color, Kent, White Art, Beverage Pack, Office Paper, Special Cutting, separate cutting, medium antique, Kent Manila, newspaper, miscellaneous paper, cut tea, plain tea, miscellaneous tea, craft corrugated cardboard, corrugated cardboard, wamp, top mount, mount, ball, etc. can be used. Among them, old white paper such as upper white, cream upper white, ruled white, card, special white, imitation, color, Kent, white art, beverage pack, office paper, etc., has high whiteness and is made of deinked pulp. It is preferable because the whiteness is easily secured to 75% or more.

  Among the above-mentioned raw pulps, it is preferable that mainly hardwood bleached kraft pulp having a whiteness of 75% or more is blended in the range of 50 to 100% by weight, and in the range of 90 to 100% by weight, in the paper or board. Is more preferable. Hardwood kraft pulp recovered from waste paper may be blended.

  In addition, softwood pulp has the property of having a long fiber length and excellent tensile strength. Therefore, the effect of improving the tensile strength, burst strength, and resistance to ruled line cracking necessary for corrugated base paper is recognized by blending softwood pulp. However, even if the softwood pulp is not blended in the present paper or board, there is no problem because the strength and printability necessary for the present paper or paperboard can be obtained if other conditions are defined.

  Furthermore, the paper thickness of the main paper or paperboard is lower than that of a multi-layer paperboard made from raw pulp made of conventional corrugated cardboard. Therefore, by making the mechanical pulp 3 wt% or more, preferably 3 to 30 wt%, more preferably 10 to 25 wt%, it is possible to ensure the necessary compressive strength as a used paper container such as a confidential used paper collection box, Corrugated cardboard cases made of genuine paper or paperboard while collecting and storing confidential used paper are easy to permeate water and are suitable for solubility when recycled as used paper pulp.

  Furthermore, JIS-P8226 “Fiber length measurement method by automatic optical analysis of pulp” of pulp (hereinafter also referred to as “disaggregated pulp”) obtained by disaggregating this paper or paperboard by a method according to JIS-P8220 (1998). The weight average fiber length (hereinafter, referred to as “average fiber length”) measured by Metso FiberLab is 0.5 to 1.5 mm, more preferably 0.7 to 1.20 mm. In addition, the scattering coefficient measured according to ISO9416 (1998) of the sheet prepared according to JIS-P8222 (1998) using the disaggregated pulp obtained by disaggregating the paper or paperboard by the method described above is preferably 35 to 80, Is adjusted to 50-80. Note that the scattering coefficient generally improves opacity, so the light scattering coefficient is referred to in the present invention.

  As described above, in order to improve the strength of the paper, the freeness of the raw material pulp is adjusted. However, the degree of influence on the quality varies greatly depending on the state of the fiber of the adjusted pulp. However, it is possible to improve the strength of the paper simply by adjusting the fiber length. However, in addition to the strength of the paper, this paper and paperboard can be subjected to a dissolution treatment for reuse. It has been found that it is important to grasp the state of fiber fluff on the paper surface in obtaining properties.

  Therefore, in the present invention, in order to grasp the fluffing state of the fiber, it has been found that the fiber quality is managed by the light scattering coefficient that has been conventionally measured for the purpose of opacity, and the fiber length is set to a specific range. Thus, it was found that the paper or paperboard of the present invention can be obtained.

  In addition, if the weight average fiber length is less than 0.5 mm, the tensile strength and elongation tend to decrease and tend to be weak against bending stress. There is a problem that causes slitter paper dust when a small bobbin is processed for use as a paper tube base paper. On the other hand, if it exceeds 1.5 mm, the resistance to ruled line cracking will be good, but the surface of the paper or paperboard will be uneven, and it will be susceptible to the unevenness of this surface when performing a small bobbin processing, This tends to be a bamboo shoot-like winding, which is not preferable.

  On the other hand, when the scattering coefficient is less than 35, the fiber surface is less fuzzy and there is a tendency for the bonding and entanglement between the fibers to be reduced, so that the tensile strength is lowered. On the other hand, if the scattering coefficient exceeds 80, fuzz on the surface of the fiber increases and the bonding and entanglement of the fibers improves, but the fibers tend to be relied on in the raw slurry, and the lump of the fibers is relied on. Since it may generate | occur | produce on paper as a foreign material, it is not preferable.

  Furthermore, the free paper of the disaggregated pulp (hereinafter referred to as “disaggregation freeness”) measured according to JIS-P8121 (1995) is 220 to 580 cc, more preferably 400 to 535 cc. adjust. When the disaggregation freeness is less than 220 cc, the fineness of the fibers proceeds and the drainage speed becomes slow. As a result, the paper-making property tends to be remarkably lowered, which is not preferable. On the other hand, when the disaggregation freeness exceeds 580 cc, the drainage speed becomes too fast and the entanglement of fibers on the wire is lost. As a result, the wet paper strength is lowered, and a paper breakage trouble is likely to occur, which is not preferable.

In addition, the basis weight of the paper or paperboard is preferably 120 to 210 g / m ² so that the paper or paperboard can be used for all of the exterior liner, interior liner and core base paper of the cardboard sheet. It is more preferable to set it as 140-180 g / m < ² >. Particularly, by setting the basis weight of the main paper or paperboard to 140 to 180 g / m ² , the same main paper or paperboard can be used as the exterior liner, the interior liner, and the core raw paper constituting the corrugated cardboard sheet. . When the basis weight is less than 120 g / m ² , it is difficult to satisfy the strength as a container for storing confidential waste paper when the main paper or paperboard is used as an exterior liner or interior liner of a corrugated cardboard sheet. On the other hand, when the basis weight exceeds 210 g / m ² , there is a problem that dissolution and disintegration properties are lowered in the process of dissolving the corrugated cardboard case while collecting and storing the confidential waste paper, and it takes much time to dissolve.

  The paper or paperboard is preferably coated with a coating solution on at least one side, and preferably on both sides. In this case, it is preferable to apply or impregnate by a transfer coating method such as a gate roll using a coating solution containing a water-soluble resin having good paper permeability and good film-forming properties. In this way, a coating liquid containing a water-soluble resin is applied and dried to form a coating layer. Thus, even if waste paper pulp containing ash is blended as a main component such as magazine waste paper, JIS-P8129 (1997) The surface strength at the Denison wax value specified in (1) can be set to 13A or more, and the occurrence of ruled line cracking is also suppressed while maintaining the printability, the bonding property, and the tensile strength necessary for conveying the contents. be able to. Furthermore, it is possible to improve the compressive strength as a corrugated cardboard sheet and the ease of dissolution / disaggregation when processing as used paper.

The coating amount per side of the coating liquid (hereinafter simply referred to as “coating amount”) is 0.1 to 10 g / m ² , more preferably 0.2 to 5.0 g / m ² . It is preferable. As a result, the main paper or the paperboard has the ability to be fed as a core base paper while maintaining the tensile strength, bonding suitability, and printability necessary for the outer liner and interior liner of the cardboard case. . Therefore, the main paper or the paperboard can be used for all of the exterior liner, the core base paper, and the interior liner, and all the corrugated board sheets can be formed of the same base paper. In addition, when the coating amount of the coating liquid is less than 0.1 g / m ² , the surface strength tends to be weak, and fluffing occurs during box making, pasting and printing, and the suitability as a corrugated cardboard sheet tends to be lost. On the other hand, when the coating amount exceeds 10 g / m ² , the surface strength is improved. However, when used as a core raw paper, step cracking is likely to occur in the repetitive step.

Below, the coating liquid containing the water-soluble resin used suitably for this paper or board is explained in full detail.
Various known water-soluble resins can be used as the water-soluble resin contained in the coating liquid used for the present paper or paperboard, but it is preferable to add starch, more preferably styrene resin. . As a result, it is excellent in tensile strength, resistance to ruled line cracking, printability, and the ability to improve the corrugating process as the core base paper of the corrugated cardboard sheet. In addition, the compressive strength of the cardboard case formed using the cardboard sheet used for the interior liner can be increased, and further, dissolution and disintegration can be improved in the step of dissolving the cardboard case as it is.

  As the starch blended in the present coating solution, a modified starch having a molecular weight of less than 3 million, preferably from 2.3 million to 2.9 million is suitable. The form in which the starch is provided to the paper manufacturer is a solid material, and generally the higher the starch molecular weight, the slower the solid starch dissolves in the aqueous system. In addition, starch having a particularly high molecular weight exhibits a very high sensitivity to shearing, which causes a problem that handling and quality control become difficult. Therefore, when starch is used, it is necessary to dissolve the starch in an aqueous solution in advance. However, if the starch has a molecular weight of 3 million or more, it is necessary to perform strong mixing in order to ensure complete dissolution. There is. However, when such a strong mixing operation is performed, the high molecular weight starch exhibits high sensitivity to shearing, so that high molecular weight characteristics cannot be obtained. In the finally obtained starch dispersion, The starch cannot be uniformly dispersed. For this reason, a starch having a molecular weight of less than 3 million is used for the starch used for the paper or board. However, even if the molecular weight of the starch is less than 3 million, or if the molecular weight is too low, at least when applied to the front and back surfaces of the base paper, the viscosity is low and the film thickness is poor. Since it does not stop on the front and back surfaces and is likely to penetrate into the paper, it tends to be inferior in terms of surface strength. Therefore, it is more preferable to use starch having a molecular weight of 2.3 million or more.

  Examples of such starch include various known ones such as oxidized starch, cationized starch, carboxymethylated starch, pregelatinized starch, phosphate esterified starch, urea phosphate-modified starch, and unmodified starch. Or 2 or more types can be mixed and used. In addition, since these starch raw materials are not particularly limited, for example, various known raw material starches such as tapioca starch, potato starch, sweet potato starch, wheat starch, sago starch, rice starch, and corn starch are used alone. Or 2 or more types can be mixed and used.

Among these starches, it is preferable to use phosphoric acid-modified starch, particularly phosphoric acid esterified starch and / or urea phosphoric acid-modified starch. Further, in the case of phosphoric acid esterified starch, phosphoric acid modified starch having a binding rate of phosphoric acid of 0.1 to 10% by weight as phosphoric acid H ₃ PO ₄ per solid content of phosphoric acid esterified starch. Use is preferred. Phosphoric acid-modified starch has a low increase in viscosity even at a high concentration, and is excellent in coatability. In addition, since it has moderate permeability into the base paper, it ensures adequate water permeability while maintaining the tensile strength, bonding suitability, and printability required for the base paper used for corrugated cardboard sheets. be able to.

Moreover, the starch used for this paper or paperboard is the value analyzed by the colorimetric determination of the starch by the phenol-sulfuric acid method, and in this paper or paperboard, starch is 2.5-10 g / m < ² >, Preferably 3.0- It is preferable to apply the coating liquid so as to contain 5 g / m ² . In addition, when paper or paperboard having a starch content of less than 2.5 g / m ² is used for an exterior liner and an interior liner, while maintaining the compressive strength, bonding suitability, and printability necessary for the cardboard case, It becomes difficult to improve the bonding and boxing suitability. On the other hand, when the starch content exceeds 10 g / m ² , the coating layer becomes hard, the resistance to ruled line cracking deteriorates, and the water permeability deteriorates. Sex is reduced.

Furthermore, the starch content in the base paper is such that the starch has a coating solution concentration of 35% and a viscosity at a temperature of 40 ° C. of 85 cp or less, preferably 10 to 80 cp, more preferably 30 to 75 cp. It becomes easier to apply so as to be 2.5 g / m ² or more. Accordingly, it is possible to have the suitability for sheeting as a core base paper while maintaining the tensile strength, the bonding suitability, and the printing suitability required for the exterior liner and interior liner of the cardboard case. Therefore, this paper or paperboard can be used for the exterior liner, the core base paper, and the interior liner, and all the corrugated board sheets can be formed from the same base paper.

  Moreover, polyvinyl alcohol (PVA), polyacrylamide (PAM), etc. other than starch can be used for a coating liquid in the range which does not affect the effect of this invention. Further, for example, a lubricant, a sizing agent, a filler dispersant, a pH adjuster, a thickener, a fluidity improver, an antifoaming agent, an antifoaming agent, a release agent, a penetrating agent, a coloring dye, a coloring pigment, an ultraviolet absorber, You may add well-known additives, such as antioxidant, antiseptic | preservative, antibacterial agent, water-proofing agent, and fluorescence quencher, individually or in mixture of 2 or more types.

  In particular, when using this paper or paperboard as the core raw paper, it is necessary to be suitable for the stepping process, and in the stepping process with the corrugator roll, the stepping and step cracking will not occur. Further, it is preferable to apply a non-wax lubricant.

  As the lubricant, those mainly composed of fluororesin (solid, powder, fibrous, etc.) are used. In addition, liquid type lubricants can be used in combination with silicone oil, synthetic oil such as fluorine oil, animal oil such as squalane oil, vegetable oil such as rapeseed oil, safflower oil, sesame oil, coconut oil, mineral oil, etc. Any means for obtaining lubricity is effective, but in view of long-term stability, it is desirable to use a synthetic oil such as silicone oil or fluorine-based oil. Silicone oils include methylphenyl oil, fluorosilicone oil, dimethyl silicone oil, modified silicone oils such as polyether, fluorine, epoxy, and alcohol. Although there are some differences in effect, they can be used almost as a lubricant. . Examples of the fluorine-based oil include fluorocarbon oil and perfluoroether oil.

  Moreover, a higher fatty acid metal salt such as calcium stearate and an aqueous dispersion of low molecular weight polyethylene can be preferably used. Among these, liquid hydrocarbon oils, higher fatty acids, higher alcohols, higher fatty acid sulfated oils, aliphatic phosphate esters, polyalkylene glycols or derivatives thereof, aqueous dispersions thereof, paraffin wax, microcrystalline wax, etc. Oil wax or the like can be used. However, since petroleum wax has a low effect of suppressing the generation (dust generation) of paper dust, it is particularly preferable to use a non-wax lubricant.

  The paper or paperboard has an inorganic pigment content of less than 10% by weight, preferably less than 5% by weight. As a result, the rigidity of the main paper or paperboard can be improved, and the suitability for crease resistance can be improved.

Then, using a calender or the like in which metal rolls such as soft calender and hard chilled ore are stacked, the paper density of the paper or paperboard is adjusted to 0.5 to 0.8 g / cm ³ . When the paper density is less than 0.5 g / cm ³ , unevenness on the surface of the coating layer formed by applying the coating liquid to the surface layer or the like becomes large, which causes printing blur. On the other hand, when it exceeds 0.8 g / cm ³ , the flexibility is lowered, so that there is a problem that suitability for crease resistance is lowered.

By these, especially as an exterior liner, an interior liner, and a core base paper constituting a corrugated cardboard sheet, a basic paper having a basis weight of 120 to 210 g / m ² , particularly 140 to 180 g / m ² and the same basis weight, or Paperboard can be used.

  This paper or paperboard forms wet paper with a headbox equipped with a mechanism that can adjust the concentration of the raw material pulp in the width direction. Can be applied to the front and back surfaces of wet paper and dried.

  In high-speed papermaking at 700 m / min or more, the coating solution is preferably applied to the main paper or paperboard at a concentration of 1.0 to 2.5%. When the concentration is less than 1.0%, mist is generated particularly in the gate roll, and the surrounding facilities may be soiled. In addition, it is difficult to apply the required amount of coating liquid, and excessive drying capacity is required, resulting in a problem that operability is lowered. On the other hand, if the concentration exceeds 2.5%, the viscosity becomes high, so that the paper is taken off during coating, paper breakage occurs, and a running trouble occurs, resulting in a problem of reduced operability.

  The paper or paperboard can also be used as a paper tube base paper. In particular, the tensile strength (longitudinal) is preferably 10.9 to 24.7 kgf, particularly 15.0 to 20.0 kgf. When the tensile strength (longitudinal) is less than 10.9 kgf, it becomes difficult to adjust the tension in the process of manufacturing the paper tube using the paper or paperboard finished with a small width as the paper tube base paper. It becomes difficult to use for tubes. On the other hand, even if the tensile strength (longitudinal) exceeds 24.7 kgf, flexibility is lost, which is not preferable as a paper tube base paper.

Newspaper or paperboard described above, for example newspaper or paperboard 170 g / ^{m 2} as an exterior liner, newspaper or paperboard 170 g / ^{m 2} as an interior liner of the corrugating medium 170 g / ^{m 2} of actual paper or board, the same rice Even if a corrugated cardboard sheet is formed using base paper with the same specifications as the tsubo, a corrugated cardboard sheet having suitability for pasting, bonding and box making can be obtained. In this way, even if the corrugated cardboard sheet is composed only of main paper or paperboard, it satisfies processing suitability such as bonding, box making, and resistance to cracking of ruled lines. Thus, it is possible to obtain a corrugated cardboard case having easy solubility and easy disintegration that can be dissolved for reuse. Further, unlike the conventional case, there is no need to stock out the exterior liner, the interior liner, and the core base paper, and as a result, there is an advantage that it is not necessary to manage the stock of complicated base paper.

  The corrugated cardboard sheet or cardboard sheet is processed into a corrugated cardboard case that serves as a container for collecting and storing confidential used paper by folding or the like, but the processing applied to the corrugated cardboard sheet is not particularly limited. Various known processes can be performed.

  Furthermore, since it is processed while being wound around a spiral to be used as a paper tube base paper, it is used while being slitted to a winding width of 3 to 150 mm and used under severe tension conditions. However, this paper or paperboard has a function that can be sufficiently used as a paper tube base paper.

  In order to confirm the effect of the paper or paperboard according to the present invention, the following various samples were prepared, and a test for evaluating the quality of each sample was performed. Note that the present embodiment does not limit the present invention, and it is needless to say that the configuration can be changed as appropriate without departing from the scope of the claims.

  25 types of examples (referred to as “Example 1” to “Example 25”) were produced with the structure shown in Table 1, and for comparison with these Examples 1 to 25 These two types of paper or paperboard (referred to as “Comparative Example 1” and “Comparative Example 2”) were prepared as shown in Table 1. Also, a corrugated cardboard case produced using a commercially available white liner is referred to as Reference Example 1, and a corrugated cardboard case produced using commercially available high-quality paper is referred to as Reference Example 2, using a paper or paperboard according to the present invention. Compared with. It should be noted that all the factors of each example and comparative example are not newly established individual lines, but are mainly test examples by a test plant.

[Example 1]
After blending 100% by weight of LBKP, the raw pulp was adjusted with a double disc refiner so that the Canadian standard freeness (according to JIS-P8121) was 500 cc to prepare a raw pulp slurry.
Next, as the water-soluble resin, oxidized starch having a molecular weight of 2.9 million (SK-20, manufactured by Nippon Corn Starch Co., Ltd.) was used, and the water-based resin was adjusted so that the concentration of the applied aqueous composition was 2.0%. A coating liquid containing a conductive resin was prepared.
The raw material pulp slurry prepared as described above is put into a module jet head box (manufactured by VOITH), and the concentration is adjusted so that the concentration of the raw material pulp becomes 1.0% to form a single layer wet paper. . Thereafter, the wet paper is dehydrated by a water squeezing method and dried by a predryer to form a base paper. The paper making speed is 700 m / min.
Next, the coating liquid containing the above-described water-soluble resin is applied to the front and back surfaces of the wet paper with a gate roll so that the starch content in the base paper is 2.5 g / m ^2, and dried. The finished moisture is within the range of 8.0 ± 1.5% defined by JIS-P3904, the basis weight is 170 g / m ² , the paper density is 0.80 g / cm ³ , and the paper thickness is 212 μm. Paper or paperboard (Example 1) is obtained. In addition, starch content is the value quantified using the analytical curve created with the oxidation starch in the colorimetric analysis using a phenol-sulfuric acid method, and paper thickness is JIS-P8118 (2006) "paper and It is a value measured on the basis of “paperboard—thickness and density test method”.
In addition, calcium stearate (Nopcoat C-104: manufactured by San Nopco, solid content concentration 50%) was used as a lubricant, and was applied and transferred with a sprayer of an after dryer.

[Examples 2 to 22 and Comparative Examples 1 and 2 and Reference Example 1]
Further, Examples 2 to 22 were produced in the same manner as in Example 1 except for the conditions shown in Table 1, and Comparative Examples 1 and 2 were produced in the same manner as in Example 1 except for the conditions shown in Table 1. Evaluation was performed. In Table 1, “Type of water-soluble resin”, “D” represents phosphate esterified starch, “Urine” represents urea phosphate-modified starch, and “Styrene” represents styrene. Represents resin. Further, as Reference Example 1, a commercially available white liner is used for all of the exterior liner, the interior liner, and the core base paper to prepare a corrugated cardboard sheet. Further, as Reference Example 2, a commercially available high quality paper is used as an exterior liner, Corrugated cardboard sheets were prepared using all of the interior liner and the core raw paper.

  In Table 1, “Fiber length (mm)” is measured by FiberLab manufactured by Metso, which is a testing machine that can measure pulp disaggregated by a method based on JIS-P8220 (1998) according to JISP8226 (2006). It is a measured value of the weight average fiber length.

  The “scattering coefficient” is a value obtained by measuring a sheet, which is each prepared sample, according to ISO9416 (1998).

  “Freeness (cc)” is a value measured according to JIS-P8121 (1995).

  The “ash content (%)” is a value measured according to JIS-P8251 (2003).

“Basis weight (g / m ² )” is the basis weight of each sample, that is, the entire paper or paperboard, and was measured according to “Paper and paperboard—basis weight measurement method” described in JIS-P8124. Value.

“Paper density (g / cm ³ )” is a value calculated using the basis weight and thickness of each sample. In addition, in order to eliminate a measurement error, it is an average value obtained by measuring 10 samples from each sample.

  Table 2 shows the results of quality evaluation for all of these Examples and Comparative Examples. This quality evaluation test was performed under environmental conditions of temperature 23 ± 2 ° C. and humidity 50 ± 2% in accordance with JIS-P8111.

  “Tensile strength (longitudinal) (kgf)” in Table 2 is a longitudinal strength value obtained by measuring white kraft paper as each sample according to JIS-P8113.

  The “wax value (A)” is used to evaluate the surface strength, and is measured by the Dennison wax value defined in JIS-P8129 (1997).

In addition, “adhesion suitability” means that a corrugated cardboard sheet is formed by using each sample of paper or paperboard as an outer liner, an inner liner, and a core base paper, and a corrugated cardboard case is formed using the corrugated cardboard sheet. The workability at that time was evaluated. The evaluation criteria were as follows.
(Double-circle): At the time of pasting, there was no jump, the exterior liner, interior liner, and core raw paper could be pasted, and there was no sheet curvature.
○: Although stepping was recognized at the time of pasting, the exterior liner, the interior liner, and the core base paper could be pasted, and there was no sheet warpage.
Δ: Stepping occurs at the time of bonding, and it is difficult to bond the exterior liner, the interior liner, and the core base paper.
X: Jumping and step cracking occur at the time of pasting, and the outer liner, the inner liner, and the core base paper cannot be pasted.

In addition, “ruled line cracking suitability” refers to whether or not a crack is generated at the top of a fold by folding the flap of the corrugated cardboard case 180 ° using each sample paper or paperboard. And the crack per 20 cm width was evaluated. The evaluation criteria were as follows.
(Double-circle): The crack was not recognized.
○: There are less than 3 cracks with a width of less than 2 mm.
Δ: There are three or more cracks with a width of less than 2 mm.
X: The crack exceeding 2 mm has generate | occur | produced continuously.

Furthermore, “disaggregation” means that each sample paper or paperboard is used to pack 2500 sheets of P4 used paper of A4 size in the cardboard case (440 mm × 310 mm × 230 mm) created, 50 cases were prepared. While the flap portion was laminated with a white kraft tape was charged with cardboard case 50 case pulper, further charged with water 10 m ^3, was dissolved 40 minutes, the dissolved waste paper pulp was visually observed, which was evaluated is there. The evaluation criteria were as follows.
(Double-circle): It melt | dissolved completely in 40 minutes and the undissolved substance was not recognized.
○: Some undissolved waste paper is recognized, but there is no problem.
Δ: Undissolved waste paper of 3 mm or more is observed.
X: There is clearly undissolved waste paper.

As can be seen from Table 2, the paper or paperboard according to the present invention, that is, the paper or paperboard according to Examples 1 to 25, is excellent in bonding suitability and ruled line cracking resistance, and is also excellent in disaggregation. Therefore, the paper or paperboard according to the present invention can be used as an exterior liner, interior liner, and core base paper used for a corrugated cardboard case with a basis weight of 120 to 210 g / m ² , particularly 140 to 180 g / m ² . A corrugated cardboard case made using the same paper or paperboard according to the present invention for all of the exterior liner, interior liner, and core base paper can maintain sufficient strength as a used paper collection container. In addition, as described above, the cardboard case made using the paper or paperboard according to the present invention has high disaggregation property and is easy to disaggregate, so that it can be dissolved even in an unpacked state in which confidential used paper is stored. Since it can be processed, confidentiality as a confidential waste paper collection container can be maintained, and disaggregated pulp can be used for fine waste paper.

In addition, since the paper or paperboard according to the present invention can be used as a core base paper constituting the corrugated cardboard sheet, the corrugated cardboard sheet can be easily manufactured at a low cost with the same material. The manufacturing cost can be further reduced. On the other hand, as shown in Reference Example 1 and Reference Example 2, corrugated cardboard sheets formed by using conventional white liners and high-quality papers for all of the exterior liner, the core base paper, and the interior liner are affixed. Suitability is low or disaggregation is bad. Therefore, it is necessary to prepare different varieties for the exterior liner, the core raw paper, and the interior liner, which is complicated and increases the cost.

Claims (3)

A corrugated cardboard sheet comprising an outer liner, a core base paper, and an inner liner,
Paper or paperboard is used for all of the exterior liner, the core base paper, and the interior liner,
The paper or paperboard uses a pulp having a whiteness of 75% or more based on JIS-P8141 as a raw material pulp,
The disaggregated pulp disaggregated by the method according to JIS-P8220 (1998) has a weight average fiber length measured by Metso FiberLab according to JIS-P8226, 0.5 to 1.5 mm, and the disaggregated pulp is Used, and the scattering coefficient measured according to ISO9416 (1998) of the sheet prepared according to JIS-P8222 (1998) is 35-80 .
A corrugated cardboard sheet characterized in that a coating liquid containing a water-soluble resin is applied to at least one surface, and the Denison wax value defined in JIS-P8129 (1997) is 13A or more . The paper or paperboard, the content of the inorganic pigment is less than 10 wt%, cardboard sheet according to claim 1, the paper density is characterized by a 0.5~0.8g / cm ^3. The corrugated cardboard sheet according to claim 1 or ² , wherein a coating amount of the coating liquid per side of the paper or paperboard is 0.1 to 10 g / m2 .