JP6817042B2 - Composite white paperboard - Google Patents

Description

The present invention relates to a composite white paperboard obtained by bonding, and more specifically, it is suitable for use on the cover, text, etc. of a picture book for young children, and has a good touch and is easy to turn and bonded. The present invention relates to a composite white paper sheet that can appropriately hold water-soluble glue on a surface, has good adhesiveness, and is highly productive.

Regarding the white paperboard for the above-mentioned use, Patent Document 1 (WO2015 / 041276) states that a hardwood made of three or more layers and having a bulk of 3.0 to 3.8 cm ³ / g. A white paperboard is described in which bleached chemithermomechanical pulp (LBCTMP) is blended only in the middle layer in an amount of 10 to 50% by weight based on the total pulp raw material in the middle layer, and the surface layer, the middle layer and the back layer are combined. The white paperboard described in Patent Document 1 is a paperboard having three or more layers having outer layers on both sides of the middle layer, and is a bulky paperboard (single paper) in which the middle layer is mainly composed of mechanical pulp. ..

Further, Patent Document 2 (Japanese Unexamined Patent Publication No. 2010-150696) describes a coated white paperboard mainly used for paper containers such as cosmetic boxes and gift case boxes, or book covers, and has excellent surface quality and a blank coated surface. A coated white paperboard having a high 75-degree ISO glossiness and excellent processing suitability such as gluing is described. The coated white paperboard described in Patent Document 2 is used for a book cover or the like, and is considered to be excellent in processing suitability such as gluing between paperboards.

WO2015 / 041276 Japanese Unexamined Patent Publication No. 2010-150696

A composite white paperboard having the characteristics of being comfortable to the touch and easy to turn over, which is suitable for use on the cover, text, etc. of a picture book for young children intended in the present invention, using only the white paperboard described in Patent Document 1 above. It's difficult to do.

Further, even in the case of the coated white paperboard of Patent Document 2, it is difficult to have a characteristic that it is comfortable to touch and easy to turn, which is suitable for use on the cover, text, etc. of a picture book for young children intended in the present invention. .. In Patent Document 2, there is no particular description regarding the details of the bonded product.

As described above, in the case of the white paperboard used for the purpose of the book cover, etc., which has been conventionally proposed, all of them relate to the white paperboard alone or the white paperboard before bonding, and therefore, the invention of the present invention is made. It was difficult to provide the characteristics of composite white paperboard, which is suitable for use on the cover and text of picture books for young children, and has a good touch and is easy to turn.

Therefore, it is an object of the present invention to provide a bulky composite white paper sheet that is comfortable to the touch and easy to turn over, and has properties necessary for use in the cover, text, etc. of a picture book for young children. Another object of the present invention is to obtain a highly productive composite white paper sheet having sufficient glue retention, which is indispensable for bonding.

As a result of diligent research to solve the above problems, the present inventors have made a white paperboard, which is suitable for the cover and text of a picture book for young children, by sticking it instead of a single paper, and has a good touch. We came up with the idea that it could be a composite white paperboard with characteristics that make it easy to turn over, and completed the present invention.

The invention according to claim 1 for solving the above problems has a coating layer mainly composed of pigment on both sides, the coating amount of the pigment in at least one surface of the coating layer of said coating layer 1.0 to 10.0 g / ^{m 2} der is, Cobb water absorption of the surface coating amount of the pigment having a coating layer is 1.0 to 10.0 g / ^{m 2} is from 18.0 to 28. 0 g / ^{m 2} der Ru white paperboard two or more, the coating layer between the coating amount of the pigment is 1.0 to 10.0 g / ^{m 2} through the water-soluble glue is stuck conjoined It is a composite white paperboard characterized by being formed.

In one embodiment, the coating amount of the pigment is 2.5 to 9.8 g / m ² .

In one embodiment, the water-soluble glue has a solid content of 5.0 to 15.0 g / m ² .

In one embodiment, the white paperboard contains 10 to 50% of LBCTMP having a bulk of 3.0 to 3.8 cm ³ / g in its middle layer with respect to all the raw materials of the middle layer, and the LBCTMP is Maple. It is said to be LBCTMP obtained from the genus.

The composite white paperboard according to the present invention has coating layers on both sides, and the coating amount mainly containing a pigment in the coating layer on at least one side of the coating layers is 1.0 to 10.0 g / m. It is characterized in that two or more white paper sheets of No. ² are bonded and bonded together via a water-soluble glue, and since the coating amount of the coating layer is within the above range, it is water-soluble. It has the effects that the retention of the sex paste is good, the adhesiveness is good, the productivity is high, the degree of curl at the time of binding is small, and the ease of turning is good when the book is bound.

Further, since the composite white paperboard according to the present invention is bulkier than the conventional white paperboard, it is lighter than the high-grade white paperboard of the same thickness, and in particular, the cover / text of a child's book, or a catalog, poster, pamphlet, calendar, etc. It has a high cushioning property that is suitable as a white paperboard for printing or a paperboard for paper containers such as food containers, and it has a particularly soft feel, and it causes injuries when an infant turns not only the cover but also all pages. This has the effect of obtaining a composite white paperboard with excellent safety.

Further, the invention according to claim 2 has an effect of improving the adhesiveness between white paper sheets, and the invention according to claim 3 has an effect of further improving the adhesiveness between white paper sheets. In the invention according to claim 4, a uniform glue-coated surface can be obtained and the glue retention property in the coating layer is improved. In the invention according to claim 5, the glue amount is an appropriate amount. There is an effect that the amount is insufficient to cause poor bonding, and the amount of glue is excessive to cause poor drying of the glue, thereby preventing a decrease in productivity.

Further, in the inventions according to claims 6 and 7, since LBCTMP is blended in the middle layer, there is an effect that the bulk of the white paperboard is increased and the formation of the middle layer is improved.

It is a simplified block diagram of the composite white sheet paper which concerns on this invention.

A mode for carrying out the present invention will be described with reference to the accompanying drawings. The composite white paperboard according to the present invention has coating layers on both sides, and the coating amount mainly containing a pigment in the coating layer on at least one side of the coating layers is 1.0 to 10.0 g / m. It is characterized in that two or more white paper sheets A and B, which are No. ² , are formed by being bonded and bonded together via a water-soluble glue.

The white paper sheets A and B to be bonded together have a surface layer 2, a middle layer 3, and a back layer 4, and the amount of pigment applied to at least one side (usually, the back layer 4) is 1.0 to 10. It has a back coating layer 5 which is a thin coating layer of .0 g / m ² (preferably 2.5 to 9.8 g / m ² ). Here, if the pigment coating amount of the back coating layer 5 is less than 1.0, the water-soluble glue described later is absorbed by the pinholes of the back coating layer 5, and the retention of the glue is lowered, which is not preferable. .. On the other hand, when the pigment coating amount exceeds 10.0 g / m ² , the specific gravity of the pigment itself is high, so that the coating amount becomes excessive, and the white paperboard and the composite white paperboard obtained by joining and laminating the white paperboard are used. The bulkiness is reduced. By providing the back coating layer 5 on the back layer 4 in this way, it is possible to suppress the infiltration of water glue, and thus high productivity and clean lamination become possible.

Thus, a backing coating layer 5 provided on the customary backing layer 4, a thin coating layer of the coated amount 1.0 to 10.0 g / ^{m 2} (tentatively, coating amount 10.0 g / ^{m 2} The following cases are referred to as a thin coating layer, and more cases are referred to as a heavy coating layer), but the surface coating layer 1 on the opposite surface layer 2 side is a case where printing is applied later. Is a heavy coating layer of pigment which is about the same as or twice as much as the back coating layer 5. The pigments used for the back coating layer 5 and the front coating layer 1 include commonly used heavy calcium carbonate, light calcium carbonate, casein, clay, starch, titanium oxide, plastic pigments, etc., and the adhesives include Known materials such as SBR latex, starch, casein, and polyvinyl alcohol can be used.

The Cobb water absorption degree (an index indicating the size water repellency of the surface) of the surface having the back coating layer 5 needs to be 18.0 to 28.0 g / m ² . If the water absorption of the hump is less than 18.0 g / m ² , a uniform glue-coated surface cannot be obtained, and if it exceeds 28.0 g / m ² , the glue penetrates into the back coating layer 5. The glue retention in the back coating layer 5 is reduced.

In the case of laminating two composite white paper sheets according to the present invention, water-soluble glue having a solid content of 5.0 to 15.0 g / m ² between the back coating layers 5 of the white paper sheets A and B. It is formed by joining and pasting together. Here, if the solid content of the water-soluble glue is less than 5.0 g / m ² , the amount of glue is insufficient and bonding is poor, and if it exceeds 15.0 g / m ² , the amount of glue is excessive. Not only does it cause poor drying of the glue, resulting in reduced productivity, but it is also uneconomical to use unnecessarily excessive glue.

Examples of the water-soluble glue used for this bonding include acetoacetylated polyvinyl alcohol obtained by acetacetylating a water-soluble polymer compound such as polyvinyl alcohol, hydroxyalkyl cellulose, and starch, acetoacetylated hydroxyalkyl cellulose, and acetoacetylated starch. Aqueous solution of When used in picture books for infants, it is desirable to use starch-based glue that does not cause hygiene problems even if it is contained in the mouth of an infant.

In the case of bonding two sheets of the composite white paperboard according to the present invention, it is usually manufactured by bonding and bonding the back coating layers 5 to each other via the water-soluble glue layer 6. It is also possible that the layer 5 and the surface coating layer 1 are bonded together. The basis weight of the composite white paper sheet according to the present invention is 450 to 950 g / m ² depending on the intended use.

In the production of the composite white paperboard according to the present invention, first, the white paperboards A and B which are the base papers including the surface layer 2, the middle layer 3 and the back layer 4 are manufactured, and preferably the middle layer 3 is obtained from hardwood. LBCTMP is used. In that case, it is preferable to blend LBCTMP obtained from the genus Maple, which contributes to the improvement of the formation among LBCTMPs.

In order to obtain the bulky white paperboard intended in the present invention, it is desirable that the bulk of LBCTMP is 3.0 to 3.8 cm ³ / g. The term "bulk" as used herein means that pulp is hand-made in accordance with JIS P8222: 1998, and the bulk of the hand-made paper is measured in accordance with ISO 534: 1988. The bulk is 3.0 to 3.8 cm ³ By using LBCTMP of / g, the desired composite white paperboard density is finally obtained.

In a preferred embodiment, the white paper sheets A and B are produced by blending the bulk LBCTMP only in the middle layer 3. The reason why the LBCTMP blending is limited to the middle layer 3 in this way is that when the LBCTMP is blended in the front layer 2 and the back layer 4, paper dust derived from LBCTMP is generated and falls off from the front and back surfaces of the paper, which is the papermaking. This is because it causes stains and a decrease in paper strength in the process and the coating process.

When LBCTMP having a bulk of 3.0 to 3.8 cm ³ / g is used, the formation of the middle layer 3 is better than when other BCTMPs are blended. The formation is important for forming the layer structure, and if the formation of the middle layer 3 deteriorates, the smoothness of the surface layer 2 and the back layer 4 in contact with the middle layer 3 will be adversely affected.

Further, in order to obtain a bulky white paperboard, it is desirable that the content of LBCTMP in the middle layer 3 having a bulk of 3.0 to 3.8 cm ³ / g is 10 to 50%. By setting the blending ratio of LBCTMP to the middle layer 3 to 10 to 50% in this way, the density of the entire white paperboard is 0.78 to 1.00 g / m ² (preferably 0.80 to 0.96 g / m). It is possible to set to ² ). When the composite white paperboard according to the present invention is used as a white paperboard for printing, if the density is less than 0.78 g / m ² , the smoothness of the front surface and the back surface is lowered and the printability is deteriorated. On the other hand, if the density exceeds 1.00 g / m ² , the paper becomes too hard and problems such as spine cracking are likely to occur during printing and binding, which is not preferable.

Since the composite white paperboard according to the present invention is used as a cover / text of a picture book, a paperboard for printing catalogs, posters, pamphlets, calendars, etc., and a food container, N-BKP and L-BKP other than LBCTMP , Mechanical pulp and other virgin pulp are blended. In particular, in the case of applications such as picture books and food containers, it is desirable to blend non-fluorescent pulp. Further, when the waste paper pulp is blended, the quality including strength and the appearance are deteriorated. Therefore, it is desirable not to blend the waste paper pulp in other than the middle layer.

Hereinafter, the present invention will be further described based on Examples, but it goes without saying that the present invention is not limited to those Examples. In Examples 1 to 3 and Comparative Examples 1 to 4 shown below, two sheets of three-layer paperboard are laminated with water-soluble glue. The numerical values indicating the basis weight and solid content in Table 1 are numerical values based on JIS P8124: 2011 in the humidity control state specified in JIS P8111: 1998.

[Manufacturing of white paperboard]
The pulp composition of the surface layer 2 and the back layer 4 is N-BKP 10% and L-BKP 90%, and the composition of the middle layer 3 is N-BKP 10%, L-BKP 40%, LBCTMP (Tembec, TEMCEL400 / 80, bulk 3.4 cm). ³ / g) 50%, each layer is made by combining each layer with a multi-layer paperboard machine, and the pigment mainly composed of heavy calcium carbonate is applied to the surface layer 2 using a blade coater. After applying 8.0 g / m ² to the surface layer 2 and the back layer 4 (glue-bonded surface), a pigment mainly composed of 70% fine kaolin and 30% heavy calcium carbonate is applied on both sides with an air knife. (The amount of coating applied to the back layer 4 is as shown in Table 1), and a white paperboard having a basis weight of about 450 g / m ² was produced.

[Manufacturing of composite white paperboard]
Two sheets of white paperboard manufactured as described above are prepared, and the back coating layer 5 of one of the white paperboards A is used as a glue-bonded surface, and water-soluble starch paste for interleaving paper (Sacraanol SP-310B) is used on that surface. : Ishizuka Sangyo) is glued with a paper interleaving machine at intervals of 1 mm in width, and the back coating layer 5 which is the laminating surface of the other white paperboard B is laminated and bonded, and the humidity is adjusted and dried for one day to make a composite white paperboard. Got Hereinafter, Examples 1-3 and Comparative Example 2 are obtained by laminating white paper sheets having the same configuration.

[Manufacturing of interleaving picture books]
Using the composite white paperboard manufactured as described above, a 10-sheet interleaving picture book was prepared by the following general bookbinding process.
Printing book → Cutting → Folding in half → Collating paper → Rounded corners → Walnut made of fine material → Finish

[Example 1]
Bookbinding was performed with the amount of pigment applied to the glue-bonded surface (back coating layer 5) of the white paperboard set to 7.0 g / m ² and the solid content of the water-soluble glue set to 7.0 g / m ² .

[Example 2]
Bookbinding was carried out in the same manner as in Example 1 except that the amount of pigment applied to the glue-bonded surface was 2.5 g / m ² and the solid content of the water-soluble glue was 6.0 g / m ² .

[Example 3]
Pigment coating amount 9.5 g / m 2 of adhesive lamination ^surface, except that the 14.5 g / m ² solids of the water-soluble glue in the same manner as in Example 1, were bound.

[Comparative Example 1]
Bookbinding was performed in the same manner as in Example 1 except that the amount of pigment applied to the glue-bonded surface was 11.0 g / m ² .

[Comparative Example 2]
White paperboard was produced in the same manner as in Example 1 except that the glue-bonded surface was not pigment-coated and only the surface was coated with two layers, but bookbinding was not performed due to poor bonding.

≪Test method and evaluation≫
・ Cobb water absorption (immersion for 30 seconds): JIS P8140: 1998
・ Adhesion of two sheets of white paperboard
[Evaluation]
◯: Good (I tried to peel off the two white paper sheets that were pasted together after humidity control by hand, but they did not peel off.)
Δ: Slightly defective (slightly easy to peel off by the same peeling method)
X: Defective (easily peeled by the same peeling method)
・ Curl degree of bookbinding: Comprehensive evaluation of 5 workers [evaluation]
○: No curl, △: Slightly curled, ×: Curl is large and defective ・ Easy to turn when binding a bonded product (touch): Workers about ease of turning (flexibility) when turning a book Comprehensive evaluation of 5 people [evaluation]
◎: Best, ○: Good, △: Slightly bad, ×: Bad

<Table 1>

In Examples 1 to 3 shown in Table 1, which are within the scope of the matters specified in the claims of the present application, the point of stickability of the two white paper sheets and the curl when the bonded product is bound. Good evaluation was obtained in both the degree and ease of turning.

On the other hand, in Comparative Examples 1 and 2, since the amount of pigment applied to the glue-bonded surface was not within the range specified in the present invention, the evaluation was inferior to that of Examples in both the adhesiveness and the bookbinding suitability. ..

The composite white paperboard according to the present invention is suitable for use as a cover or text of a picture book for young children, but in addition, a paperboard for printing such as catalogs, posters, pamphlets, and calendars, and a drawing sheet. It is also suitable for use in paperboard for food containers such as food paper containers, cup noodle containers, paper cups, confectionery boxes, and tobacco cartons, and has great industrial utility.

A, B White paperboard 1 Front coating layer 2 Surface layer 3 Middle layer 4 Back layer 5 Back coating layer 6 Water-soluble glue layer

Claims (5)

Has a coating layer mainly composed of pigment on both sides, Ri least the coating amount of the pigment in the one surface of the coating layer is 1.0 to 10.0 g / m ² der of said coating layer, the pigment the coated amount 1.0 to 10.0 g / ^m Cobb water absorption of the surface having the coating layer is ² 18.0~28.0g / ^{m 2} der Ru white paperboard two or more water-soluble A composite white paperboard characterized in that coating layers having a coating amount of 1.0 to 10.0 g / m ² of the pigment are bonded and bonded to each other via glue. The composite white paperboard according to claim 1, wherein the coating amount of the pigment is 2.5 to 9.8 g / m ² . The composite white paperboard according to claim 1 or 2 , wherein the water-soluble glue has a solid content of 5.0 to 15.0 g / m ² . The white paperboard according to any one of claims 1 to 3 , wherein the middle layer contains 10 to 50% of LBCTMP having a bulk of 3.0 to 3.8 g / m ² with respect to all the raw materials of the middle layer. Composite white paperboard. The composite white paper sheet according to claim 4 , wherein the LBCTMP is an LBCTMP obtained from the genus Maple.

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