AU2013236640B2

AU2013236640B2 - White paper board, and printed matter, printed box or packaging container each produced using same

Info

Publication number: AU2013236640B2
Application number: AU2013236640A
Authority: AU
Inventors: Yuji Kojo; Takashi Muranaka; Daisuke Nagata
Original assignee: Nippon Paper Industries Co Ltd
Current assignee: Nippon Paper Industries Co Ltd
Priority date: 2012-03-22
Filing date: 2013-01-23
Publication date: 2017-04-13
Anticipated expiration: 2033-01-23
Also published as: WO2013140844A1; JP6189287B2; AU2013236640A1; CN104334798A; JPWO2013140844A1

Abstract

A white paper board in which the formation state of a paper layer is improved and of which the rigidity and the degree of whiteness can be controlled. The white paper board has a multi-layered structure composed of three or more layers, wherein an inorganic filler is added to each of a front-side layer and a back-side layer in an amount of 1.0 to 9.0% relative to the amount of pulp fibers, the inorganic filler is added to an intermediate layer in an amount of 2.0 to 15.0% relative to the amount of the pulp fibers, and the white paper board is produced by combining the front-side layer, the intermediate layer and the back-side layer. As the inorganic filler, at least one component selected from light calcium carbonate, heavy calcium carbonate, clay and talc or a combination of two or more components selected from the above-mentioned materials is used. For example, the light calcium carbonate is of a rosetta type.

Description

WHITE PAPER BOARD, AND PRINTED MATTER, PRINTED BOX OR PACKAGING CONTAINER EACH PRODUCED USING SAME BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to a white paper board and a packaging carton using the same, and more particularly, to a white paper board which is comprised of two or more plural layers, can be controlled for a moderate stiffness and brightness, and is intended for improved formation, as well as a printed matter, printed box, and packaging carton which are manufactured using the white paper board.

Description of the Related Art [0002] White paper boards are multilayer paperboards having two or more layers and can be divided into two broad general categories: manila board with which the surface layer and the back layer are mainly compounded with bleached pulp, while the middle layer (an intermediate layer excluding the surface layer and the back layer, this definition being applicable hereafter) is compounded with pulp, waste paper, and the like; and white fined board with which the surface layer is mainly compounded with bleached pulp, while the middle layer and the back layer are mainly compounded with waste paper.

[0003] The manila board is used for printed matters, such as calendars, cards, book covers, illustrated reference books, picture postcards, and for printed boxes, such as fancy boxes, soap boxes, gift cases, cigarette cartons, caramel boxes, while the white fined board is used for packaging cartons such as those for foodstuff, miscellaneous goods, detergents and the like. For either of the manila board and the white fined board, a paint containing a filler is generally coated thereon in order to improve the printabifity, the smoothness, and the concealing property.

[0004] Conventionally, there has been a technique which specifies the beating freeness for the surface layer or the surface lower layer (a layer just below the surface layer) of a white paper board to be 250 to 500 cc, and the content of the pigment contained in the aforementioned layer to be 10 wt.% or over based on pulp, thereby intending to improve the concealing property 1 H:\kxg\Interwoven\NRPortbl\DCC\KXGM3540673_ I-doai-22/03/2017 2013236640 22 Mar 2017 of the white paper board (concealing the color of the waste paper compounded in the middle layer), the visual smoothness, the printability, the front surface strength, the measure against ruled line crack (the freedom from the ruled line part being cracked when a box is made from the white paper board), and the like (Patent Document V Japanese Patent No. 3008313).

[0005] With the invention disclosed in this Patent Document 1, a pigment of 10 wt.% or over is contained in the surface layer, however, this will relatively lower the compounded amount of pulp, the filler inhibiting the hydrogen bonding between pulp fibers, which provides a main factor of paper strength development, thereby the paper strength being abruptly lowered. Generally, paper strengths include strengths, such as tensile strength, and stiffnesses, such as flexural rigidity, however, a reduction in these paper strengths will cause a paper breakage at the time of manufacturing or printing, resulting in a deteriorated efficiency of operation, and occurrence of paper powder, and the like, at the time of printing, bringing about decreased workability.

[0006] There has been another technique which specifies the ash content in the back layer of a white paper board comprised of three or more layers to be 12% or under on average, and 14% or under at maximum, thereby intending to improve the preservability of the white paper board, and alleviate the problem of back fuzz during transportation (Patent Document 2- Japanese Unexamined Patent Application Publication No. Hei 10-96199).

[0007] However, the invention disclosed in Patent Document 2 is specialized only in the ash content of the back layer, and alleviation of the problem of back fuzz, and thus differs in course of action from the claimed invention, which is intended to provide a white paper board allowing control for a moderate stiffness, and having been improved in formation and brightness.

[0008] Japanese Patent No. 3008313

Japanese Patent Application Publication No. Hei 10-96199 [0009] As described above, there has conventionally been not proposed a white paper board which is improved in formation of a paper layer, and can be controlled for stiffness and brightness. One or more embodiments of the present invention may provide such a white paper board, in other words, a white paper board which has been improved in formation of a paper layer, and can be controlled for stiffness and brightness. 2 H:\kxg\fnterwoven\NRPortbl\DCC\KXGM 3540673_1 .docx-22/03/2017 2013236640 22 Mar 2017

SUMMARY OF THE INVENTION

[0010] The invention provides a multilayered white paper board comprised of three or more layers, comprising a surface layer and a back layer each being compounded with an inorganic filler so as to contain 1.0 to 9.0% inorganic filler based on pulp fiber, and a middle layer being compounded with an inorganic filler so as to contain 2.0 to 15.0% inorganic filler based on pulp fiber, the multilayered white paper board being provided by laminating the surface layer, middle layer, and back layer one upon another.

[0011] The aforementioned inorganic filler may be one of or a combination of more than one of light calcium carbonate, heavy calcium carbonate, clay, and talc.

[0012] In a preferred embodiment, the aforementioned fight calcium carbonate is specified to be of rosette-type.

[0013] Further, the invention provides printed matter, printed box, or packaging carton which is obtained from any of the aforementioned white paper boards.

[0014] The present invention is as described above, and since each of the surface layer and the back layer of a white paper board comprised of three or more plural layers is compounded with an inorganic filler, such as fight calcium carbonate or heavy calcium carbonate, so as to contain the inorganic filler by 1.0 to 9.0% based on pulp, there may be provided an advantage that good entanglement with the mixed pulp is achieved, thereby the formation of the surface layer and the back layer being improved (if the content of the pulp is close to 100%, too much entanglement is caused between pulp fibers, thereby the formation being deteriorated), and that, with the formation being improved, the smoothness in the surface layer and the back layer is improved.

[0015] In addition, with the middle layer being also compounded with an inorganic filler by 2.0 to 15.0%, it is made possible to obtain a moderate stiffness and brightness of the white paper board. In other words, generally, it is often the case that the middle layer is compounded with waste paper pulp or circulated broke (broke-equivalent paper which occurs at a plant during manufacturing) for such a purpose as cost cutting, and the surface layer and the back layer are compounded with virgin pulp in order to provide printability improvement, however, the middle layer may have a lowered brightness due to the quality of the aforementioned compounded pulp, but with the formation of the surface layer and the back layer being improved as described above, a uniform layer structure may be provided, whereby it is made possible to conceal the color of the middle layer (which is a concealing effect). 3 H:\kxg\Interwoven\NRPortbl\DCC\KXG\l 3540673_l.docx-22/03/2017 2013236640 22 Mar 2017 [0016] In addition, by replacing pulp with a specific content of a filler, the stiffness of paper can be moderately improved, whereby an effect of improving the processing suitability, such as paper box making suitability.

[0017] A white paper board in accordance with the present invention is a multilayered white paper board comprised of three or more layers, comprising a surface layer and a back layer each being compounded with an inorganic filler so as to contain 1.0 to 9.0% inorganic filler based on pulp fiber, and a middle layer being compounded with an inorganic filler so as to contain 2.0 to 15.0% inorganic filler based on pulp fiber, the multilayered white paper board being provided by laminating the surface layer, middle layer, and back layer one upon another.

[0018] As the filler in the present invention, one of the inorganic fillers, such as fight calcium carbonate, heavy calcium carbonate, clay, calcined kaolin, delaminated kaolin, white carbon, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, calcium carbonate/sifica composite, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, and sepiofite, may be used, or a plurality of these inorganic fillers may be used in combination. Alternatively, a recycled filler may be used which can be obtained by incinerating sludge occurring in the process of regenerating waste paper or paper manufacturing.

[0019] As the filler in the present invention, fight calcium carbonate is particularly recommended. The crystalline form of fight calcium carbonate may be either calsite or aragonite, and the geometry thereof may be needle-like, columnar, spindle-shaped, spherical, cube-shaped, or rosette-type. Among these, rosette-type calsite based fight calcium carbonate is particularly preferable. The rosette-type geometry refers to a geometry produced by agglomerating spindle-shaped fight calcium carbonate primary particles into a burr-fike form, featuring a high specific surface area and oil absorbability. The calcium carbonate average particle diameter may be 0.1 to 20 μηι or so, preferably 0.5 to 10 pm, and more preferably 1 to 5 pm.

[0020] The base paper for white paper board is made by a multilayer papermaking machine for two or more layers, and in the surface layer and 4 the back layer, bleached pulp or non-bleached pulp of wood pulp or mechanical pulp is compounded in consideration of the printability. Such pulps have a filler content of 0.5% or so, and thus in consideration of the yield, the surface layer and the back layer are compounded with an inorganic filler such that the content thereof is 1.0 to 9.0%, respectively. For example, for the surface layer and the back layer, the bleached pulp, which contains less filler, is added with a fresh inorganic filler to thereby provide a content of 1.0 to 9.0%.

[0021] In the middle layer including the surface lower layer, in order to reduce the cost, waste paper pulp of magazine waste paper, cardboard waste paper, or the like, or a broke-equivalent circulated broke which occurs at a plant is compounded besides the aforementioned pulp. In consideration of that the aforementioned bleached pulp has a filler content of approx. 0.5%; that the waste paper pulp has a filler content of 10% or over (varying depending upon the type and collection condition of waste paper); that the circulated broke has a filler content of 2.0 to 20.0% (generally, a circulated broke contains a filler coated broke or a non-coated base paper, or a mixture of these, or the like, however, the filler in the circulated broke at a plant is of the same type as that of the filler in the claimed invention); and the yield, the middle layer is compounded with an inorganic filler such that the content thereof is 2.0 to 15.0%. For example, for the middle layer, the circulated broke, which has a more filler content, is added with an inorganic filler, thereby the middle layer having a high content of the inorganic filler as compared to the surface layer and the back layer.

[0022] After a base paper for white paper board having been made by a multilayer papermaking machine, a normal coating apparatus (a curtain coater, a blade coater, an air knife coater, or the like) is used to coat one side or both sides of the base paper with a normal color blended paint (a blended liquid consisting of light calcium carbonate, heavy calcium carbonate, clay, plastic pigment, and others) by single coating (one-time coating) or double coating (two-times coating) in the range of coating rate of 20 to 40 g/m2 to thereby manufacture a white paper board having a basis weight of 160 g/m2 to 420 g/m2, or so.

[0023] The base paper for white paper board in accordance with the claimed invention is made by a multilayer papermaking machine, such as a Fourdrinier, cylinder, or Ultraformer multilayer papermaking machine, and 5 H:\kxg\fnterwoven\NRPortbl\DCC\KXGM 3540673_l.docx.-22/03/20l 7 2013236640 22 Mar 2017 then a paint containing an inorganic pigment is coated on one side or both sides as required.

[0024] [Examples]

Hereinbelow, embodiments of the present invention will be further explained on the basis of Examples, however, needless to say, the present invention will not be hmited to those Examples. Examples 1 to 7 (Table l) and Comparative Examples 1 to 12 (Table 2) given below are all of three-layered white paper board. The numerical values indicating compounding are numerical values based on the weight of the solid content.

[0025] <Evaluation/test method>

Basis weight: JIS P 8124 Thickness/density: JIS P 8118

Formation: Light is shined on the paper front surface from diagonally above to visually check for uniformity of fibers in the front surface and unevenness condition of the paper surface. (In Tables 1 and 2, the marks A and B expresses "excellent" and "good", respectively, indicating it is acceptable, while the marks C and D expresses "fair" and "poor", respectively, indicating it is unacceptable.)

Stiffness: JIS P 8143 (15.0 to 20.0 indicates a satisfactory stiffness.) Smoothness: JIS P 8155 ISO (For both front and back surfaces, 750 or over indicates a satisfactory smoothness.)

Brightness: JIS P 8148 (For both front and back surfaces, 80.5 to 84.5 indicates a satisfactory brightness.)

Delamination strength: In conformity to JAPAN TAPPI No. 19-2 Method B. (56 or over indicates a satisfactory delamination strength) [0026] <Examples 1 to 7>

As Examples 1 to 7, white paper boards were manufactured by variously changing the content of the inorganic filler in the surface layer and the back layer in the range of 1.0 to 9.0%; compounding the middle layer with an inorganic filler such that the content thereof is 2.0 to 15.0%; using the aforementioned papermaking method to make a base paper for white paper board in three layers; and thereafter coating the aforementioned color blended paint on both sides by double coating such that the basis weight is 20 g/m2 in total. In the middle layer, a broke of the same type that occurs at a plant (having a filler content of 10% or so) were compounded by 50%.

[0027] <Comparative Examples 1 to 11> 6

As Comparative Examples 1 to 11, white paper boards were manufactured by papermaking and coating in the same manner as in Examples 1 to 7, except that the content of the inorganic filler in the surface layer and the back layer was variously changed such that it was out of the range of 1.0 to 9.0%, depending upon the Comparative Example; and the middle layer was compounded with an inorganic filler such that the content thereof is out of the range of 2.0 to 15.0%, depending upon the Comparative Example.

[0028] Comparative Example 12>

As Comparative Example 12, a white paper board was manufactured in the same manner as in Example 1 except that the middle layer was not compounded with a broke.

[0029] <Table 1> 7

Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Surface layer basis weight: 25% Compounded pulp NBKP % 20 20 20 20 20 20 20 LBKP % 80 80 80 80 80 80 80 Compounded filler Rosette-type light CaCO? % based on pulp good good good good good Spindle-shaped light CaCOj % based on pulp good Heavy CaCOj S: based on pulp good Surface iayer filler content “Λ based on puip 4.0 2.3 8.0 8.2 2.5 4.3 4.2 Middle iayer basis weight: 50% Compounded pulp NBKP % 10 10 10 10 10 10 10 LBKP % 40 40 40 40 40 40 40 Broke % 50 50 50 50 50 50 50 Compounded filler Rosette-type light CaCOs % based on pulp good good good good good Spindle-shaped light CaCOs % based on pulp good Heavy CaCOs % based oo pulp good Middle layer filler content \ based on pulp 9.3 6.4 12.8 6.4 12.9 9.4 9.2 Back layer basis weight: 25% Compounded pulp NBKP % 20 20 20 20 20 20 20 LBKP % 80 80 80 80 80 80 80 Compounded filler Rosette-type light CaCOs % based on pulp good good good good good Spindle-shaped tight CaCOs % based oo pulp good Heavy CaCOs % based on pulp good Back layer filler content % based on pulp 4.4 2.2 8.3 1.5 8.5 4.3 4.3 Paper quality after coaOog of coating liquid Basis weight g/m2 320 322 321 320 320 321 323 Thickness mtn/100 34.5 34.4 34.9 34.7 34.6 34.6 34.3 Density g/m3 0.928 0.936 0.920 0.922 0.925 0.928 0.942 Formation Front surface Visual check A B A A s B 8 Back surface A B B B A B B Stiffness Longitudinal mN-rn 15.7 15.4 15.6 15.5 15.6 15.3 15.1 Smoothness Front surface sec 970 950 990 990 950 950 930 Back surface 960 940 990 930 990 950 940 ISO brightness Front surface % 83.7 83.0 84.3 84.0 83.0 83.0 82.4 Back surface 83.5 83.0 84.2 82.8 84.0 83.4 82.0 Middle layer examination strength N/m 60 65 57 65 56 60 61 [0030] <Table 2> 8

Comp. e*. 1 Coop. ex. 2 Comp. Ex 3 Comp. Ex. 4 Comp. Ex. 5 Camp. sx. 5> C^p.E.7 coenp. ex β Camp. E< k Camp E«. 1C Cemp Ex. ii Camp. Ex. 12 Surface layer basis weight: 25% Compounded pulp NBKP% 20 20 20 20 20 20 20 20 20 20 20 20 L8KP% 80 80 80 80 80 80 80 80 80 80 80 80 Compounded filler Rosette-type light CaCOi % (ntnU or- ook* good good good good good SpIndie'Shaped light CaCO> \ OwO -M (uJK good Heavy CsCOs \ Oaaoo on pu» Surface layer filler content % ct(«l an jwk‘ 0.3 4.4 0.3 0.4 10.0 4.5 10.5 0.3 0.4 5.4 0.3 4.5 Middle layer basis weight: 5( % Compounded pulp NBKP % 10 10 10 10 10 10 10 10 10 10 10 20 LBKP% 40 40 40 40 40 40 40 40 40 40 40 80 Broke % 50 50 60 60 50 50 50 50 50 50 50 Compounded filler Rosette-type light CaCO? sj husurf on «>u*P good good good good Spindle-ebspeel light ChCOs bx»<l on irulp Heavy CaCOj \ on n«ly good Middle layer filler content s OOOCd u>! {WM 5.4 5.6 9.3 5.3 16.5 16.5 5.3 15.5 5.3 5.3 9.4 0.5 Bach layer basis weight: 25^ Compounded pulp NBKP % 20 20 20 20 20 20 20 20 20 20 20 20 LBKP % 80 80 80 80 SO 80 80 80 60 80 80 80 Compounded fiber Rosette-type light CaCO: % UvwU on good good good good good good Spindle-shaped tight CaCCh « css«c on pulp good Heavy CaCOa S Oasad cr ;<utp good Back layer filler content Ά (?*«*<] or· οιΊμ 0.4 0.3 0.3 4.4 10.0 4.5 0.5 10.8 10.6 0.5 3.3 4.5 Peoor c-aslity »h»r coming of sowing llfloirl Basis weight 321 322 321 320 321 321 322 321 322 320 319 320 Thickness mm/100 34.1 34.3 34.3 34-3 35.0 35.0 34.5 35.0 34.6 34.3 34.2 34.2 Density g/m’ 0.941 0.939 0.936 0.933 0.917 0.917 0.933 0.917 0.931 0.933 0.933 0.936 Formation Front surface Visual check B A C D 8 A B c O 8 O C Back surface D D 0 C 8 A D B B C C C Stiffness Longitudinal mNm 15.0 15.0 16.0 15.1 14.3 14.5 14.8 14.5 14.6 14.9 15.2 15.1 Front surface sec 880 920 870 830 960 970 950 890 860 910 880 920 Bee* surfacs 880 880 860 870 970 960 880 690 940 890 870 920 ISO brightness From surface % 80.8 82.1 81.0 80.3 84.8 84.5 84.8 B0.6 80.2 82.0 80.2 81.5 Back surface 80.6 80.8 81.S 82.0 84.6 84.0 81.0 84.7 84.0 81.3 81.5 82.0 Middle layer doiomirortlpo etrangth Him 70 72 56 86 48 48 68 49 65 64 58 60 [0031] As can be seen from the results in Table 1, Examples 1 to 7, which meet all the requirements in the claimed invention, gave good formation and smoothness, and satisfactory values of stiffness and brightness. On the other hand, as can be seen from the results in Table 2, in Comparative Examples 1 to 4, and 7 to 11, with which either or both of the surface layer and the back layer has a content of the inorganic filler of less than 1.0%, the pulp content of the front surface or the back surface was too much increased, resulting in not only the formation of the front and back surfaces being deteriorated, but also the stiffness indicating a downward tendency. If the stiffness is lowered, the box processing suitability would be adversely affected in the subsequent process (when the white paper board is formed into a box, the ruling would be adversely affected).

[0032] In addition, in Comparative Examples 5, and 7 to 9, with which either of both of the surface layer and the back layer has a content of the inorganic 9 H:\kxg\Interwoven\NRPortbl\DCC\KXG\l 3540673_l.docx.-22/03/2017 2013236640 22 Mar 2017 filler of over 9.0%, the inorganic filler content was too much increased, resulting in the stiffness of the white paper board being contrarily lowered. Further, the brightness also exceeded a desired numerical value. In Comparative Examples 5, 6, and 8, with which the middle layer has a content of the inorganic filler exceeding the range of 2.0 to 15.0%, the delamination strength of the middle layer was reduced, with the box processing suitability being deteriorated. Further, in Comparative Examples 5, 6, and 8, the stiffness was lowered. In Comparative Example 12, with which the middle layer has a content of the inorganic filler of less than 2.0%, the rate of the pulp in the middle layer was too much increased, resulting in the formation of the middle layer being deteriorated to thereby deteriorate the formation of the surface layer and the back layer.

[0033] From the above results, it could have been confirmed that the white paper board in accordance with the claimed invention that is manufactured, the content of the inorganic filler in the surface layer and the back layer being set in the range of 1.0 to 9.0%, and the content of the inorganic filler in the middle layer being set in the range of 2.0 to 15.0%, is effective in every of the viewpoints of formation, smoothness, stiffness, and brightness. In addition, the packaging box manufactured by using this white paper board in accordance with the present invention has a good appearance and a moderate stiffness.

[0034] Hereinabove, the present invention has been explained in detail to some extent, and about the most preferred embodiment, however, it is obvious that a wide range of different embodiments can be made without departing from the spirit and scope of the present invention. Therefore, it is to be understood that the present invention is not hmited to the specific embodiments thereof except as defined in the appended claims.

[0035] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

[0036] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 10

Claims

What is claimed is^

1. A multilayered white paper board comprised of three or more layers, comprising a surface layer and a back layer each being compounded with an inorganic filler so as to contain 1.0 to 9.0% inorganic filler based on pulp fiber, and a middle layer being compounded with an inorganic filler so as to contain 2.0 to 15.0% inorganic filler based on pulp fiber, the multilayered white paper board being provided by laminating the surface layer, middle layer, and back layer one upon another.
2. The white paper board according to Claim 1, wherein said inorganic filler is one of or a combination of more than one of hght calcium carbonate, heavy calcium carbonate, clay, and talc.
3. The white paper board according to Claim 2, wherein said hght calcium carbonate is of rosette type.
4. A printed matter, printed box, or packaging carton which is obtained from the white paper board claimed in any one of Claims 1 to 3.