JP2017160576A - Coated paper used for lamination applications and cardboard sheet containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated paper excellent in paper durability and high speed lamination compatibility and used for lamination applications and a cardboard sheet using the same.SOLUTION: There is provided a coated paper containing a base paper and a paper strengthening agent coated on at least one surface thereof and used for lamination applications, the paper strengthening agent contains (A) at least one kind of water soluble polymer selected from a group consisting of starch, modified starch, casein, cellulose, polyvinyl alcohol and polyacrylamide, (B) one or more kind of penetrant of a compound (I) represented by the following general formula (1) and a compound (II) represented by the following general formula (3), General Formula (R)-X-[(CHO)/(AO)]-H (1) and General Formula (R)-X-[(CHO)/(AO)]-(AO)-H (3).SELECTED DRAWING: None

Description

  The present invention relates to a coated paper used for bonding purposes, and in particular, a coated paper used for bonding purposes, such as a cardboard base paper such as a liner and a core, and a corrugated cardboard including such a coated paper. Regarding the sheet.

  Among papers, those having a large paper thickness are generally referred to as paperboard, and the paperboard is generally roughly classified into three types: cardboard base paper, paperboard paperboard, and miscellaneous paperboard. Of these, corrugated cardboard is generally divided into a liner and a core. The liner and the core are each initially in the form of a roll paper wound in a roll shape, applied to a corrugator, the core is formed into a corrugated shape, and the liner is bonded to one or both sides with bonding glue. To be processed into a corrugated cardboard sheet. A cardboard box is formed from the cardboard sheet.

  In recent years, for the purpose of reducing physical distribution costs and the like, cardboard boxes, and therefore, liners used therein and core paper (corrugated cardboard) have been reduced in weight. In reducing the weight, paper with a thin paper thickness or paper with a low basis weight has been used, and along with this, the strength of the paper tends to decrease, and in terms of strength when formed in a cardboard box It may not be suitable for transporting things. As one of countermeasures against strength reduction, a method of applying a water-soluble polymer such as starch on a paper surface as a paper strength agent to impart paper strength is known.

JP2013-204186A

  However, when the coating amount of the paper strength agent is increased in order to enhance the paper strength, the film of the paper strength agent formed on the surface of the paper becomes thick. In recent years, the production of paperboard has been accelerated, and the corrugator bonding speed has also been increased. When the corrugator is fast in a state where there is a thick film of a paper strength agent on the surface of the paper, there is a problem that in the obtained corrugated cardboard sheet, the core and the liner have low adhesiveness and are easily peeled off, resulting in poor bonding suitability. .

  An object of this invention is to provide the coated paper used for the application to bond, which has sufficient paper strength, and was excellent in the bonding capability at high speed, and a corrugated cardboard sheet containing the same.

  The coated paper used for the application of the present invention for solving the above-mentioned problems, and the corrugated cardboard sheet including the same have the following aspects.

[1] A coated paper used for bonding, including a base paper and a paper strength agent coated on at least one side of the base paper,
(A) at least one water-soluble polymer selected from the group consisting of starch, modified starch, casein, cellulose, polyvinyl alcohol, and polyacrylamide;
(B) the following general formula (1) compound represented by formula (I) and the following general formula one or penetrants formula comprising two or more of the compounds represented by (3) (II) (R ¹ _{) t -X - [(C 2} H 4 O) m / (AO) n] -H (1)

Wherein R ¹ is a hydrogen atom, a methyl group, an ethyl group or a branched alkyl group having 3 to 12 carbon atoms; t is an integer from 1 to 5; X is a phenol residue; m is an average addition mole of 4 to 20 Number: A is a propylene group, butylene group or phenylethylene group; n is an average addition mole number of 0 to 4. The addition form in [] is random or block.)
Formula _{^{(R 5) t -X - [}} (C 2 H 4 O) p / (AO) q] - (AO) r -H (3)

Wherein R ⁵ is a hydrogen atom, a methyl group, an ethyl group, or a linear or branched alkyl group having 3 to 12 carbon atoms; t is an integer of 1 to 5; X is a phenol residue; p is 4 to 20 Average addition mole number; A is a propylene group, butylene group or phenylethylene group; q is an average addition mole number of 0 to 3.9; r is an average addition mole number of 0.1 to 4; Indicates a random or block shape), and
Coated paper including.

[2] R ¹ of the compound (I) or R ^{5 of the} compound (II) is represented by the following general formula (2)

(Wherein R ² represents a methyl group, an ethyl group, a propyl group or a butyl group; R ³ represents a linear or branched alkyl group having 1 to 9 carbon atoms; R ⁴ represents an alkylene group having 1 or 2 carbon atoms.)
The coated paper according to [1], which is a branched alkyl group represented by:

  [3] The coated paper according to [1] or [2], wherein the total solid content of starch and modified starch exceeds 50% by mass when the total solid content of the water-soluble polymer is 100% by mass. .

[4] The coated paper according to any one of [1] to [3], wherein the water-soluble polymer is coated on the surface in an amount of 0.25 to 3.0 g / m ² per side. .

[5] The coated paper according to any one of [1] to [4], wherein the penetrant is coated on the surface in an amount of 0.005 to 0.2 g / m ² per side.

  [6] A test piece cut to 50 mm in the papermaking flow direction and 75 mm in the direction perpendicular to the papermaking flow direction was immersed in distilled water at a temperature of 23 ° C., and the signal strength on the surface of the liner was measured at an ultrasonic frequency of 2 MHz. Sometimes, when the time from the start of immersion to the time when the signal intensity shows the maximum value is defined as the peak appearance time, the peak appearance time is 50 milliseconds or less, according to any one of [1] to [5] Coated paper.

  [7] A corrugated cardboard sheet including a core and a liner bonded to each other, wherein at least one of the core and the liner is a coated paper according to any one of [1] to [5] A corrugated cardboard sheet in which the core and the liner are bonded so that the surface becomes a bonding surface.

  [8] The corrugated cardboard sheet according to [7], wherein the core is the coated paper according to any one of [1] to [6].

  [9] The liner is the coated paper according to any one of [1] to [6], and the paper strength agent is coated only on one side of the liner, [7] or The cardboard sheet according to [8].

  According to the present invention, in a coated paper used for bonding, even if a large amount of paper strength agent is coated to obtain a target paper strength, the surface for bonding The bonding paste applied to can easily penetrate into the paper. Therefore, it is possible to provide a coated paper used for a purpose of pasting and having a sufficient paper strength and excellent in pasting suitability, and a corrugated cardboard sheet including the coated paper.

  Hereinafter, embodiments of the present invention will be described in detail. The following embodiments are for illustrative purposes, and the present invention is not limited thereto.

(Coated paper)
The coated paper of the present invention includes a base paper and a paper strength agent coated on at least one surface thereof. The coated paper of the present invention can be used for applications to be bonded, such as corrugated base paper, paperboard base paper, paper tube base paper, etc., and in particular, liners and cores constituting corrugated cardboard sheets. It is preferably used as a corrugated cardboard.

(Base paper)
The base paper of the coated paper of the present invention can be produced by a known paper making method and a known paper machine using known raw materials. For example, a papermaking raw material (paper material) can be deposited in a web shape at a wire part, and then moisture can be dried through a press part and a predryer part to produce a base paper. The base paper used in the present invention may be a single layer paper making or a multilayer paper making (multilayer paper). For example, when the coated paper of the present invention is used as a paper for corrugated cardboard sheets (corrugated paper base paper), the base paper of the coated paper may be a multi-layered paper manufactured from a stock containing waste paper pulp. preferable.

(Raw pulp)
Examples of the pulp raw material that can be used for the base paper of the coated paper of the present invention include, for example, groundwood pulp (GP), refiner groundwood pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), chemi Deinked pulp (DIP) that has been deinked by separating mechanical pulp and chemical pulp such as ground pulp (CGP), semi-chemical pulp (SCP), and kraft pulp (KP) In addition, pulp generally used as a papermaking raw material, such as used paper pulp obtained by breaking up corrugated used paper or bookbinding waste paper, can be used as appropriate, either alone or in combination. When the coated paper of the present invention is used as a corrugated cardboard, a large amount of waste paper pulp can be blended as a pulp raw material for the base paper.

(Additive)
The base paper of the coated paper of the present invention may be internally added with known paper additive. That is, the base paper may be made from a paper stock to which a papermaking additive is added. Examples of internally added papermaking additives include retention agents, freeness improvers, coagulants, sulfate bands, bentonite, silica, sizing agents, dry paper strength agents, wet paper strength agents, bulking agents, fillers, and dyes. , Paper whitening chemicals such as fluorescent brighteners, pH adjusters, antifoaming agents, UV inhibitors, fading inhibitors, pitch control agents and slime control agents can be used. For example, polyacrylamide polymer, polyvinyl alcohol polymer, cationic starch, various modified starches, dry paper strength agents such as urea / formalin resin, melamine / formalin resin; wet paper strength such as polyamide polyamine epichlorohydrin resin Agents; rosin sizing agents, AKD sizing agents, ASA sizing agents, petroleum sizing agents, sizing agents such as neutral rosin sizing agents, etc. can be suitably added.
It may contain auxiliary agents generally used for papermaking, such as fillers, antifoaming agents, and pH adjusters.

  For example, as a paper strength agent that may be internally added to the base paper, a commercially available product that is easily available from the market may be used, for example, modified starch (trade name: Pillar P4, PIRAAB STARCH Co., Ltd.). , Polyacrylamide-based dry paper strength agent (trade name: Polystron 1222, manufactured by Arakawa Chemical Industries, Ltd.), dry paper strength agent (trade name: DS4681, manufactured by Seiko PMC Co., Ltd.), and dry paper strength agent (trade name) : A paper strength agent used for ordinary paper such as Polytension 1001, manufactured by Arakawa Chemical Industries, Ltd.).

(US paper basis of the base paper)
The basis weight, paper thickness, and density of the base paper of the present invention are not particularly limited and can be appropriately selected depending on the application. For example, when the coated paper of the present invention is used as a paper for the core of a corrugated cardboard sheet, the basis weight of the base paper of the coated paper is 90 to 220 g / m ² for non-limiting purposes. Is preferably used, and 90 to 160 g / m ² is more preferably used. For example, when the coated paper of the present invention is used as a linerboard for a corrugated cardboard sheet, the basis weight of the base paper of the coated paper is 90 to 400 g / m ² without limitation for illustrative purposes. Is preferably used, and 90 to 320 g / m ² is more preferably used.

(Paper strength agent)
The coated paper of the present invention includes a paper strength agent coated on at least one surface of the base paper. The paper strength agent may be coated on both sides of the base paper. The paper strength agent of the present invention comprises a water-soluble polymer and a penetrant.

(Water-soluble polymer)
Examples of water-soluble polymers applicable to the present invention include, for example, starch, modified starch, casein, cellulose, polyvinyl alcohol, and polyacrylamide.

  Examples of the starch include corn starch, wheat starch, candy starch, potato starch, tapioca starch and rice starch.

  Examples of the modified starch include oxidized starch, esterified starch, etherified starch, crosslinked starch, and cationized starch.

  Examples of casein include milk casein.

  Examples of cellulose include hydroxypropylmethylcellulose, hydroxyethylcellulose, methylcellulose, and carboxymethylcellulose (salt).

  Examples of the polyvinyl alcohol include completely saponified polyvinyl alcohol (saponification value 98 to 99; measured in accordance with JIS K0070-1992), partially saponified polyvinyl alcohol (saponification value 87 to 89), and polyvinyl alcohol. Examples thereof include modified polyvinyl alcohol esterified with a carboxylic acid halide, and known etherified polyvinyl alcohol and acetalized polyvinyl alcohol.

  Examples of the polyacrylamide include acrylamide, a cationic vinyl monomer and an anionic vinyl monomer, and a copolymer obtained by copolymerizing the crosslinkable monomer at an appropriate ratio if necessary.

  As the water-soluble polymer, a commercially available product that can be easily obtained from the market may be used. For example, the following water-soluble polymers used in ordinary coated paper can be used. Starch (trade name: corn starch, manufactured by Oji Corn Starch Co., Ltd.), modified starch (trade name: Pillar P4, manufactured by PRIRAAB STARCH Co., Ltd.), polyvinyl alcohol (trade name: Denka Poval, manufactured by Denki Kagaku Kogyo Co., Ltd.), Polyacrylamide type paper strength agent (trade name: Polystron 1222, Arakawa Chemical Industries, Ltd.).

(Penetration agent)
As a penetrant applicable to the present invention, one or more of compound (I) represented by the following general formula (1) and compound (II) represented by the following general formula (3) are used. The penetrant which consists of a compound is mentioned.
_{^{(R 1) t -X - [}} (C 2 H 4 O) m / (AO) n] -H (1)

Wherein R ¹ is a hydrogen atom, a methyl group, an ethyl group or a branched alkyl group having 3 to 12 carbon atoms; t is an integer from 1 to 5; X is a phenol residue; m is an average addition mole of 4 to 20 Number: A is a propylene group, butylene group or phenylethylene group; n is an average addition mole number of 0 to 4. The addition form in [] is random or block.)
_{^{(R 5) t -X - [}} (C 2 H 4 O) p / (AO) q] - (AO) r -H (3)

Wherein R ⁵ is a hydrogen atom, a methyl group, an ethyl group, or a linear or branched alkyl group having 3 to 12 carbon atoms; t is an integer of 1 to 5; X is a phenol residue; p is 4 to 20 Average addition mole number; A is a propylene group, butylene group or phenylethylene group; q is an average addition mole number of 0 to 3.9; r is an average addition mole number of 0.1 to 4; (Indicates random or block shape.)

Here, R ¹ of the compound (I) and R ⁵ of the compound (II) are preferably branched alkyl groups represented by the following general formula (2).

(Wherein R ² represents a methyl group, an ethyl group, a propyl group or a butyl group; R ³ represents a linear or branched alkyl group having 1 to 9 carbon atoms; R ⁴ represents an alkylene group having 1 or 2 carbon atoms.)
Specific examples of the branched alkyl group include isopropyl, isobutyl, isohexyl, isoheptyl, isooctyl, 2-ethylhexyl; branched alkyl synthesized from dimer of isobutylene; isononyl, isodecyl; branched alkyl synthesized from trimer of propylene; isodecyl, isoundecyl , Branched alkyl groups synthesized from tetramers of isododecyl and propylene; branched alkyl groups having 6 to 12 carbon atoms synthesized by the oxo method. Particularly preferred are 2-ethylhexyl; branched alkyl synthesized from dimer of isobutylene; branched alkyl synthesized from trimer of propylene; isodecyl group.

  Compound (I) was an average of 4 to 20 moles of ethylene oxide, an average of 0 to 4 moles of propylene oxide, butylene oxide and styrene oxide added to phenol or phenol substituted with an alkyl group. The addition format may be block or random. However, propylene oxide, butylene oxide or styrene oxide added in the form of a block at the end is excluded. The number of alkyl groups substituted on phenol may be any of 1 to 5, more preferably 1 or 2, and particularly preferably 1. An alkylene oxide added to a phenol substituted with an alkyl group having a carbon number greater than 12, an average addition mole number of ethylene oxide being less than 4 or greater than 20, and an average addition mole number of propylene oxide, butylene oxide or styrene oxide When the sum of the values is larger than 4, a sufficient effect cannot be obtained. Among the compounds (I), the clouding point of the 2% aqueous solution is preferably 40 to 110 ° C, and more preferably 60 to 100 ° C. Specific examples of the compound (I) of the present invention include the following.

(I-1) Tripropylene-X- (EO) ₁₀ -H
(I-2) 2-Ethylhexyl-X- (EO) _12- H
(I-3) 2,4-Dimethylheptyl-X-[(EO) ₉ // (PO) ₂ ] -H
(I-4) Di (isobutyl) -X-[(EO) ₁₀ /// (PO) ₁ // (BO) _0.5 ] -H
(I-5) isodecyl _{-X- (EO) 4 - (BO} ) 1 - (SO) 1 - (EO) 5 -H
(I-6) Diisobutylene-X- (PO) _1- (EO) _8- H

  In the above formula, X is a phenol residue, EO is ethylene oxide, PO is propylene oxide, BO is butylene oxide, SO is styrene oxide, () the subscript on the right indicates the average number of moles added, and // is random Indicates that it is added, and-indicates that it is added in the form of a block.

In the compound (II), the alkyl group R ⁵ may be linear or branched. As the straight chain having 3 to 12 carbon atoms, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n- dodecyl group and the like, as those of the branches is the same as those of the branched alkyl group R ¹ in compound (I).

  Compound (II) is one or two of an average of 4 to 20 moles of ethylene oxide and an average of 0 to 3.9 moles of propylene oxide, butylene oxide and styrene oxide on phenol or phenol substituted with an alkyl group. An average of 0.1 to 4 moles of propylene oxide, butylene oxide or styrene oxide is further added to the terminal of the above (block or random) added. Although the number of the alkyl group substituted by phenol may be any of 1 to 5, it is preferably 1 or 2, and more preferably 1. An alkylene oxide added to a phenol substituted with an alkyl group having a carbon number greater than 12, an average addition mole number of ethylene oxide being less than 4 or greater than 20, and an average addition mole number of propylene oxide, butylene oxide or styrene oxide When the sum of the values is larger than 4, a sufficient improvement effect cannot be obtained. Furthermore, when the total number of added moles of the terminal portion of propylene oxide, butylene oxide or styrene oxide is less than 0.1, the total of the added average number of moles of the terminal portion is less than 0.1-4. Poor foam effect. Among the compounds (II), the cloud point of the 2% aqueous solution is preferably 40 to 110 ° C, and more preferably 60 to 100 ° C. Specific examples of the compound (II) of the present invention include the following.

(II-1) isooctyl _{-X- (EO) 8 - (PO} ) 0.5 -H
(II-2) tripropylene _{-X- (EO) 11 - (SO} ) 1.5 -H
(II-3) n-octyl-X- (EO) _10- (PO) ₁ -H
(II-4) diisobutylene _{-X- (EO) 12 - (PO} ) 0.5 - (BO) 1.5 -H
(II-5) isononyl-X-[(EO) ₅ // (PO) _0.3 // (SO) ₁ ]-(PO) _0.2 (BO) _0.2 -H
(II-6) 2,4-dimethylheptyl-X-[(EO) ₆ /// (BO) _0.5 ]-(PO) ₁ -H
(II-7) 2- ethylhexyl _{-X- (EO) 4 - (PO} ) 1.5 - (EO) 5.5 - (BO) 0.5 -H
(II-8) di _{(isobutyl) -X- (BO) 1 - (} EO) 12 - (BO) 1 -H
(II-9) n-decyl-X- (PO) _0.5- (EO) _10- (PO) _0.5- (SO) _0.5 -H

  In the above formula, as in the case of the compound (I), X represents an alkyl-substituted phenol residue, EO represents ethylene oxide, PO represents propylene oxide, BO represents butylene oxide, and SO represents styrene oxide. The average added mole number is indicated, // indicates that it is added in a random manner, and-indicates that it is added in a block shape.

  As the penetrant corresponding to the above-mentioned compound, commercially available products that are easily available from the market may be used. For example, penetrants such as trade names: SN-8X4681 and SN wet 984 (both manufactured by San Nopco Co., Ltd.) Can be used.

(Method for producing coated paper)
The coated paper of the present invention is obtained by applying the paper strength agent of the present invention to one or both sides of the base paper, that is, by applying the paper strength agent to the base paper by the external addition method. Can be obtained. The paper strength agent is applied to the base paper as a coating solution in the form of an aqueous solution and then dried.

  A known coating method and a known coating machine can be used for coating. The coating method may be an on-machine type in which papermaking and coating are a series of processes, or an off-machine type in which papermaking and coating are separate processes. Examples of the coating method include immersing the base paper in a paper strength agent coating solution, applying a paper strength agent coating solution to the base paper with a roll or blade, and applying a paper strength agent coating solution to the base paper. A spraying method or the like can be used. As the paper machine, for example, a 2-roll size press coater, a gate roll coater, a rod metering size press coater, a blade coater, a bar coater, a spray coater, an air knife coater, a curtain coater, or the like can be used.

  For drying after coating, a known drying method and a known dryer can be used. For example, various drying methods and dryers such as a steam superheating cylinder, a heated hot air air dryer, a gas heater dryer, an electric heater dryer, and an infrared heater dryer can be used alone or in combination.

(Amount of paper strength agent applied)
The coating amount of the paper strength agent in the present invention can be appropriately selected according to the physical properties of the base paper, the target paper strength, the target bonding suitability, and the like.

For example, the coating amount of the paper strength agent focuses on the coating amount of the water-soluble polymer from the viewpoint of obtaining the target paper strength, and the coating amount of the water-soluble polymer is, for example, converted to solid content per side Is selected to be 0.1 to 5 g / m ² , preferably 0.2 to 3 g / m ² . Further, the coating amount of the paper strength agent is focused on the coating amount of the penetrating agent from the viewpoint of obtaining the target bonding suitability, and the coating amount of the penetrating agent is, for example, 0. 001~0.5g / m ^2, is selected preferably such that 0.005~0.1g / m ^2. Generally, it is preferable that the coating amount of the penetrant increases as the coating amount of the water-soluble polymer increases.

(Combination ratio of aqueous polymer and penetrant in paper strength agent)
When the coating amount of the water-soluble polymer on the base paper is increased, the paper strength of the resulting coated paper is improved, but the bonding suitability tends to be lowered. This is because the film of the water-soluble polymer formed on the surface of the base paper becomes thick, and the penetration of the paste to be applied to the surface with a corrugator later into the base paper is hindered. Guessed. In order to obtain the target bonding suitability even when the coating amount of the water-soluble polymer is increased, it is preferable to increase the coating amount of the penetrant. According to this, the penetration of the water-soluble polymer into the base paper is improved, the thickness of the water-soluble polymer film formed on the surface of the base paper is reduced, and the bonding applied to the surface by the corrugator Since the penetration of the glue into the base paper is not hindered, it is presumed that the bonding suitability is maintained. The paper strength agent of the present invention is applied in the form of an aqueous solution containing both a water-soluble polymer and a penetrant. Therefore, in order to obtain a preferable coating amount for each of the water-soluble polymer and the penetrant in the coated paper, the blending ratio of the water-soluble polymer and the penetrant at the coating liquid stage used for coating is determined for each. It is determined so that a preferable coating amount can be realized.

(Concentration of paper strength agent in coating liquid)
The paper strength agent of the present invention is applied as a coating solution in the form of an aqueous solution. If the concentration of the water-soluble polymer in the coating liquid is too high, the viscosity of the coating liquid may increase and coating may be difficult. The concentration of the paper strength agent in the coating liquid can be any concentration as long as coating is possible from the viewpoint of operability.
(Penetration of coated paper Peak appearance time (unit: millisecond)
The coated paper of the present invention has better liquid permeability than conventional coated paper.

  The liquid permeability of the coated paper of the present invention is determined by using Emtec's “SURFACE AND SIZING TESTER (EST-12)” as a dynamic liquid permeability measuring device, and the time until the signal intensity reaches the maximum value ( Evaluation is performed by measuring (peak appearance time). Specifically, the coated paper (liner) of the present invention cut to 50 mm in the papermaking flow direction and 75 mm in the width direction perpendicular to the papermaking flow direction is used as a test specimen for measurement. The back layer side of the test specimen for measurement is fixed to a sample holder with a double-sided adhesive tape, the sample holder is immersed in distilled water having a temperature of 23 ° C. as a test solution, and a signal on the surface of the liner at an ultrasonic frequency of 2 MHz. Measure strength. The time from the start of immersion until the signal intensity reaches the maximum value is defined as the peak appearance time. The shorter the peak appearance time, the higher the liquid permeability.

  The coated paper of the present invention preferably has a peak appearance time of 60 milliseconds or less, more preferably 55 milliseconds or less, and even more preferably 50 milliseconds or less.

(Cardboard sheet)
The corrugated cardboard sheet of the present invention includes the coated paper of the present invention as a component. The corrugated cardboard sheet of the present invention can be configured to include, for example, a corrugated core and a liner bonded to one or both surfaces of the corrugated sheet. The coated paper can be included as a core and / or a liner on one or both sides. In the corrugated cardboard sheet of the present invention, the surface coated with the paper strength agent of the coated paper is used as the bonding surface.

(Manufacture of cardboard sheets)
The corrugated board sheet of the present invention can be produced by a known laminating method and a known laminating machine using a material containing the coated paper of the present invention. For example, by using a known corrugator, the coated paper of the present invention is formed into a wave shape and this is used as a core, and the other paper is used as a liner. The cardboard sheet of the present invention can be produced by laminating a liner. There are no particular restrictions on the other paper, and various types of paperboard can be used. For example, a single-layer paper or a multi-layer paperboard made from waste paper pulp or kraft pulp may be used. Alternatively, the cardboard sheet of the present invention can be produced using the coated paper of the present invention as a liner and other paper as a core. Alternatively, the coated paper of the present invention can be used for both the core and the liner to produce the corrugated cardboard sheet of the present invention. Furthermore, the coated paper of the present invention may be bonded together without forming it into a wave shape.

[Example 1]
(Manufacture of base paper)
Using pulp slurry prepared by mixing 90% by weight of cardboard waste paper (absolutely dry) and 10% by weight of waste magazine paper (absolutely dry) and adjusting Canadian Standard Freeness (CSF) to 360 ml, the back layer, back bottom layer, The middle layer, the upper and lower layers, and the surface layer were combined in this order to obtain a multilayer paper base paper having a target weight of 198 g / m ² . For the surface layer, front surface lower layer, middle layer, back lower layer and back surface layer, the product name DS4681 (starlight) of 0.3% by mass based on the total mass of pulp slurry (in terms of solid content) is used as an internal paper strength agent. PMMC Co., Ltd.), 0.05 mass% trade name polytension 1001 (Arakawa Chemical Industries, Ltd.), and 1.3 mass% sulfuric acid band were added.

(Manufacture of coated paper)
A penetrant, which is the penetrant described above, in an aqueous solution prepared by modifying a modified starch (trade name: Pillar P4, manufactured by PIRAAB STARCH Co., Ltd.) to 2.0% by mass (in terms of solid content) as a water-soluble polymer. (Product name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was mixed so as to be 0.04% by mass (non-volatile content conversion) to obtain a paper strength agent. SN-8X4681 has the above general formula (1) as a main component.

The obtained paper strength agent was used as a coating liquid for coating, and the amount of water-soluble polymer applied on both sides of the above-mentioned base paper, that is, on the surface layer and the back surface layer, was 0 by dry weight. The coated paper was coated and dried so as to be .25 g / m ² (in terms of solid content) to obtain a coated paper having a coating layer of a paper strength agent on the surface.

[Example 2]
In Example 1, a penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was mixed so as to be 0.16% by mass (in terms of non-volatile content) instead of 0.04% by mass (in terms of non-volatile content). Except for the above, coated paper was obtained in the same manner as in Example 1.

[Example 3]
In Example 1, modified starch (trade name: Pillar P4, manufactured by PIRAAB STARCH Co., Ltd.) is 5.0 mass% (solid content conversion) instead of 2.0 mass% (solid content conversion). Into the prepared aqueous solution, a penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) is mixed so that it becomes 0.1 mass% (non-volatile content conversion) instead of 0.04 mass% (non-volatile content conversion). Using the paper strength agent obtained as a coating liquid, the coating amount of the water-soluble polymer is 1.0 g / m ² (solid) instead of 0.25 g / m ² (in terms of solid content) per side in terms of dry weight. A coated paper was obtained in the same manner as in Example 1 except that the coating was performed so that

[Example 4]
In Example 3, a penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was mixed so as to be 0.25% by mass (in terms of non-volatile content) instead of 0.1% by mass (in terms of non-volatile content). Except for the above, coated paper was obtained in the same manner as in Example 3.

[Example 5]
In Example 1, a modified starch (trade name: Pillar P4, PIRAAB STARCH Co., Ltd.) was added to an aqueous solution adjusted to 10% by mass (solid content conversion) instead of 2.0% by mass. As a coating liquid for coating, a paper strength agent obtained by mixing a product name: SN-8X4681, manufactured by San Nopco Co., Ltd.) so as to be 0.1% by mass (in terms of non-volatile content) instead of 0.04% by mass. The coating amount of the water-soluble polymer was 2.0 g / m ² (in terms of solid content) instead of 0.25 g / m ² (in terms of solid content) per side in terms of dry weight, A coated paper was obtained in the same manner as in Example 1.

[Example 6]
In Example 5, a penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was mixed so as to be 0.25% by mass (in terms of non-volatile content) instead of 0.1% by mass (in terms of non-volatile content). Except for the above, coated paper was obtained in the same manner as in Example 5.

[Example 7]
In Example 5, a penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was mixed so as to be 0.5% by mass (in terms of non-volatile content) instead of 0.1% by mass (in terms of non-volatile content). Except for the above, coated paper was obtained in the same manner as in Example 5.

[Example 8]
In Example 1, a modified starch (trade name: Pillar P4, PIRAB STARCH) was added to an aqueous solution adjusted to 15% by weight (in terms of solid content) instead of 2.0% by weight (trade name: SN- 8X4681, manufactured by San Nopco Co., Ltd.) instead of 0.04% by mass, a paper strength agent obtained by mixing so as to be 0.1% by mass (in terms of non-volatile content) is used as a coating liquid for coating. Example 1 except that the coating amount was 3.0 g / m ² (in terms of solid content) instead of 0.25 g / m ² (in terms of solid content) per side in terms of dry weight. Coated paper was obtained by various methods.

[Example 9]
In Example 8, a penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was mixed so as to be 0.25% by mass (in terms of non-volatile content) instead of 0.1% by mass (in terms of non-volatile content). Except for this, coated paper was obtained in the same manner as in Example 8.

[Example 10]
In Example 8, a penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was mixed so as to be 0.5% by mass (in terms of non-volatile content) instead of 0.1% by mass (in terms of non-volatile content). Except for this, coated paper was obtained in the same manner as in Example 8.

[Example 11]
In Example 1, a 118 g / m ² the target rice basis of the base paper in place of 198 g / m ^2, the surface layer, table lower, middle, lower back, the back surface layer, as an internal paper strength agent, a pulp slurry The product name DS4681 (manufactured by Seiko PMC Co., Ltd.) of 0.5% by mass instead of 0.3% by mass based on the total mass (converted to solid content) of the product, polytension 1001 of 0.05% by mass (Arakawa) A base paper was prepared in the same manner as in Example 1 except that 2.0% by mass of sulfuric acid band was added instead of 1.3% by mass. About coating, it carried out similarly to Example 6, and obtained the coated paper.

[Example 12]
In Example 1, a 218 g / m ² the target rice basis of the base paper in place of 198 g / m ^2, the surface layer, table lower, middle, lower back, the back surface layer, as an internal paper strength agent, a pulp slurry The product name DS4681 (manufactured by Seiko PMC Co., Ltd.), 0.8% by mass instead of 0.3% by mass, based on the total mass (solid content conversion), 0.05% by mass, product name Polytension 1001 (Arakawa) A base paper was prepared in the same manner as in Example 1 except that 2.0% by mass of sulfuric acid band was added instead of 1.3% by mass. About coating, it carried out similarly to Example 6, and obtained the coated paper.

[Example 13]
In Example 1, instead of modified starch (trade name: Pillar P4, manufactured by PIRAAB STARCH Co., Ltd.) 2.0% by mass (in terms of solid content), polyacrylamide-based paper strength agent (Polymerset HP710, Arakawa Chemical) Kogyo Co., Ltd.) 4.0% by mass (converted to solid content) and 0.4% by mass of penetrant (trade name: SN-8X4681, manufactured by San Nopco) instead of 0.04% by mass (converted to nonvolatile content) % As a coating liquid for coating, and the coating amount of the water-soluble polymer is dry weight instead of 0.25 g / m ² per side (in terms of solid content). The coated paper was obtained in the same manner as in Example 1 except that the amount was 0.5 g / m ² (in terms of solid content).

[Example 14]
In Example 1, modified starch (trade name: Pillar P4, manufactured by PIRAAB STARCH Co., Ltd.) 2.0 mass% (in terms of solid content) starch (trade name: corn starch, manufactured by Oji Cornstarch Co., Ltd.) 10 Using mass% (solid content conversion), penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) instead of 0.04 mass% (non-volatile content conversion) and 0.25 mass% (non-volatile content conversion) The paper strength agent thus mixed is used as a coating solution, and the coating amount of the water-soluble polymer is 2.0 g / m ² instead of 0.25 g / m ² (in terms of solid content) per side in terms of dry weight. A coated paper was obtained in the same manner as in Example 1 except that the solid content was converted.

[Example 15]
In Example 1, PVA (trade name: Denkapoval, manufactured by Denki Kagaku Kogyo Co., Ltd.) instead of 2.0% by mass (solid content conversion) of modified starch (trade name: Pillar P4, manufactured by PIRAAB STARCH Co., Ltd.) ) 10% by mass (solid content), penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) 0.25% by mass (non-volatile content conversion) instead of 0.04% by mass (non-volatile content conversion) The paper strength agent mixed so as to become a coating liquid for coating, the coating amount of the water-soluble polymer is 2.0 g / m instead of 0.25 g / m ² (in terms of solid content) per side in terms of dry weight. ² Coated paper was obtained in the same manner as in Example 1 except that the solid content was converted to the solid content.

[Comparative Example 1]
In Example 1, coated paper was obtained in the same manner as in Example 1 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating liquid.

[Comparative Example 2]
In Example 3, coated paper was obtained in the same manner as in Example 3 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating liquid.

[Comparative Example 3]
In Example 5, coated paper was obtained in the same manner as in Example 5 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating solution.

[Comparative Example 4]
In Example 8, a coated paper was obtained in the same manner as in Example 8 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating liquid.

[Comparative Example 5]
In Example 11, coated paper was obtained in the same manner as in Example 11 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating solution.

[Comparative Example 6]
In Example 12, coated paper was obtained in the same manner as in Example 12 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating solution.

[Comparative Example 7]
In Example 13, a coated paper was obtained in the same manner as in Example 13 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating solution.

[Comparative Example 8]
In Example 14, a coated paper was obtained in the same manner as in Example 14 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating solution.

[Comparative Example 9]
In Example 15, coated paper was obtained in the same manner as in Example 15 except that the penetrant (trade name: SN-8X4681, manufactured by San Nopco Co., Ltd.) was not mixed with the coating liquid.

(Measurement and evaluation test)
The coated paper thus obtained was subjected to the following measurements and evaluations.

I. US tsubo (unit: g / m ² )
The US basis weight (basis weight) of the obtained coated paper was measured according to Japanese Industrial Standard JIS P8124 “Paper and paperboard—Measurement method of basis weight”.

II. Specific compression strength The specific compression strength of the obtained coated paper was measured according to JIS P 8126 (2005). This measurement was performed in accordance with JIS-P8111 (2007) under environmental conditions of a temperature of 23 ± 2 ° C. and a humidity of 50 ± 2%. It shows that intensity | strength is so favorable that specific compression strength is large.

III. Peak appearance time (unit: milliseconds)
As a dynamic liquid permeability measuring apparatus, “SURFACE AND SIZING TESTER (EST-12)” manufactured by Emtec was used, and the peak appearance time at which the signal intensity reached the maximum value was measured. Specifically, the back layer side of the test piece for measurement in which the liner was cut to 50 mm in the paper flow direction and 75 mm in the width direction was fixed to the sample holder with a double-sided adhesive tape, and the sample holder was a test solution at a temperature of 23 ° C. It was immersed in distilled water, and the signal strength of the liner surface was measured at an ultrasonic frequency of 2 MHz. The earlier the peak appearance time, the higher the liquid permeability.

IV. Signal strength after 0.5 seconds (unit:%)
The signal intensity 0.5 seconds after the start of immersion in the penetration characteristic curve obtained using "SURFACE AND SIZING TESTER (EST-12)" manufactured by Emtec as a dynamic liquid permeability measurement device The signal intensity at the peak showing the maximum value was expressed as 100% and expressed relatively. The measurement conditions are the same as the measurement conditions for the peak appearance time. The smaller the signal intensity after 0.5 seconds, the higher the liquid permeability.

V. Concola strength (unit: N /)
About the obtained coated paper, JAPAN TAPPI (Pulp Paper Industry Association). The concola strength was measured according to the provisions of 29 “Corrugated Core Core—Plane Compressive Strength Test Method—Concola Method”. The larger the concola strength, the higher the flat compression resistance of the paper and the better the strength.

VI. Suitability for pasting Using the coated paper of Examples and Comparative Examples as a core, using a commercially available liner (210 tsubo / m ² , made by Oji Materia Co., Ltd.) as a surface layer and a back layer liner, using a corrugator to Was laminated to prepare a corrugated cardboard sheet. The bonding suitability with a corrugator was evaluated in three stages as follows. The evaluation results were shown using symbols ◯, Δ, and × in order from the best evaluation.

○: The bonding state was good over the entire surface of the corrugated cardboard sheet, and the corrugator bonding speed could be increased.
(Triangle | delta): When the bonding speed was increased, the bonding defect might be recognized by some cardboard sheets.
X: Even at a low bonding speed, a bonding failure may be observed in a part of the cardboard sheet.

(Measurement and evaluation results)
The results of measurement and evaluation were as shown in Table 1.

(Discussion)
The coated paper of the example coated with the paper strength agent containing the penetrant showed the same strength as the coated paper of the comparative example coated with the paper strength agent not containing the penetrant. However, the peak appearance time was short and the signal intensity after 0.5 seconds was small, indicating high dynamic liquid permeability. Moreover, the coated paper of the Example showed favorable bonding suitability compared with the coated paper of the comparative example.

  The coated paper of the present invention has excellent dynamic liquid permeability while having good strength. Therefore, when the coated paper of the present invention is used for applications such as corrugated cardboard paper, the paste is easily penetrated into the paper even when a high-speed corrugator is used. The adhesiveness of the papers to be combined is high and difficult to peel off, and exhibits excellent bonding suitability.

Claims (9)

A coated paper used for bonding, including a base paper and a paper strength agent coated on at least one side of the base paper,
(A) at least one water-soluble polymer selected from the group consisting of starch, modified starch, casein, cellulose, polyvinyl alcohol, and polyacrylamide;
(B) the following general formula (1) compound represented by formula (I) and the following general formula one or penetrants formula comprising two or more of the compounds represented by (3) (II) (R ¹ _{) t -X - [(C 2} H 4 O) m / (AO) n] -H (1)
Wherein R ¹ is a hydrogen atom, a methyl group, an ethyl group or a branched alkyl group having 3 to 12 carbon atoms; t is an integer from 1 to 5; X is a phenol residue; m is an average addition mole of 4 to 20 Number: A is a propylene group, butylene group or phenylethylene group; n is an average addition mole number of 0 to 4. The addition form in [] is random or block.)
Formula _{^{(R 5) t -X - [}} (C 2 H 4 O) p / (AO) q] - (AO) r -H (3)
Wherein R ⁵ is a hydrogen atom, a methyl group, an ethyl group, or a linear or branched alkyl group having 3 to 12 carbon atoms; t is an integer of 1 to 5; X is a phenol residue; p is 4 to 20 Average addition mole number; A is a propylene group, butylene group or phenylethylene group; q is an average addition mole number of 0 to 3.9; r is an average addition mole number of 0.1 to 4; Indicates a random or block shape), and
Coated paper including. R ¹ of the compound (I) or R ^{5 of the} compound (II) is represented by the following general formula (2)
(Wherein R ² represents a methyl group, an ethyl group, a propyl group or a butyl group; R ³ represents a linear or branched alkyl group having 1 to 9 carbon atoms; R ⁴ represents an alkylene group having 1 or 2 carbon atoms.)
The coated paper of Claim 1 which is a branched alkyl group represented by these.   The coated paper according to claim 1 or 2, wherein the total solid content of starch and modified starch exceeds 50 mass% when the total solid content of the water-soluble polymer is 100 mass%. The coated paper according to any one of claims 1 to 3, wherein the water-soluble polymer is coated on the surface in an amount of 0.25 to 3.0 g / m ² per side. The coated paper according to any one of claims 1 to 4, wherein the penetrant is coated on the surface in an amount of 0.005 to 0.2 g / m ² per side.   When a test piece cut to 50 mm in the paper flow direction and 75 mm in a direction perpendicular to the paper flow direction is immersed in distilled water at a temperature of 23 ° C., and the signal intensity on the surface of the liner is measured at an ultrasonic frequency of 2 MHz, The coated paper according to any one of claims 1 to 5, wherein the peak appearance time is 50 milliseconds or less when the time from the start of immersion to the time when the signal intensity shows the maximum value is defined as the peak appearance time.   A corrugated sheet including a core and a liner bonded to each other, wherein at least one of the core and the liner is the coated paper according to any one of claims 1 to 5, A corrugated cardboard sheet in which the core and the liner are bonded so that the surface becomes a bonded surface.   The corrugated cardboard sheet according to claim 7, wherein the core is the coated paper according to any one of claims 1 to 6.   The corrugated cardboard according to claim 7 or 8, wherein the liner is the coated paper according to any one of claims 1 to 6, and the paper strength agent is coated only on one side of the liner. Sheet.