JP2008115514A - Additive for coated paper, paper coating liquid containing the same, and coated paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide good gloss even in a situation where it is difficult to obtain gloss such as when using a paper coating solution with an increased amount of calcium carbonate or when making a coated base paper bulky, and furthermore, it has high shear viscosity and release Provides coated paper additives that do not adversely affect moldability, printability, etc., paper coating liquids containing these additives, and coated papers obtained by coating with these paper coating liquids To do.
An additive for coated paper includes a polyethylene glycol (a1) having a number average molecular weight of 500 to 50,000, a polyoxyethylene compound (a2) obtained by adding ethylene oxide to a compound (x) having a hydroxyl group, and the polyoxy It contains at least one (a) selected from the group consisting of fatty acid ester (a3) of ethylene compound (a2) and fatty acid (b). The paper coating solution contains a pigment (A), a polymer binder (B), and the coated paper additive (C). The coated paper is obtained by applying the paper coating solution to the surface of the coating base paper.
[Selection figure] None

Description

  The present invention relates to an additive for coated paper, a paper coating solution containing this additive, and a coated paper obtained by coating with this coating solution.

  Conventionally, in order to improve paper surface properties such as paper smoothness, glossiness, printability, etc., a slurry-like coating comprising a white pigment such as kaolin or calcium carbonate and a polymer binder added to an aqueous medium. It is well known to apply a liquid to a base paper. As a coating method in this case, in general, the coating liquid is supplied from the preparation tank to the coating head and applied to the running paper, and the excess coating liquid is removed by a blade or the like and returned to the tank. A circulation method of coating liquid is widely adopted, such as mixing with a new coating liquid and using it again for coating.

  By the way, in recent years, due to soaring raw material prices, relatively inexpensive calcium carbonate is used as a pigment used in coating liquids at a higher blending ratio, and the roll pressure has to be reduced along with the increase in bulkiness of coated base paper. Therefore, it has become difficult to give sufficient gloss to the coated paper.

As a method for improving the glossiness of coated paper, a method of adding water-soluble urethane obtained by reacting polyethylene glycol and diisocyanate together with latex or methacrylic acid polymer (Patent Document 1), Methods of adding an ionic surfactant have been proposed (Patent Documents 2 and 3). However, all of these methods have some effect of improving the glossiness of the coated paper, but on the other hand, the coating workability is improved by increasing the high shear viscosity or decreasing the releasability. The problem that it deteriorates and the problem that the printability of the coated paper deteriorates are caused.
As described above, in recent changes in the coating liquid composition and the situation in which coated paper using bulky paper is increasing, it imparts good gloss to the coated paper, and has high shear viscosity and release properties. There is a demand for an additive for coated paper that does not adversely affect the properties of the coating liquid such as the property and printability.

Japanese Patent No. 2873368 JP-A-8-188988 Japanese Patent Laid-Open No. 4-12689

  Therefore, the present invention can provide good glossiness even in situations where it is difficult to obtain glossiness, such as when using a paper coating solution with an increased amount of calcium carbonate or when making a bulky coated base paper. Additives for coated paper that do not adversely affect viscosity, releasability, printability, etc., paper coating liquid containing this additive, and coated paper obtained by coating with this paper coating liquid The purpose is to provide.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have incorporated the following (a) component having a moisturizing ability and the following (b) component that is an oil component, thereby including the above-mentioned problem. The present inventors have found that this can be solved and have completed the present invention.

That is, this invention consists of the following structures.
(1) Polyethylene glycol (a1) having a number average molecular weight of 500 to 50,000, polyoxyethylene compound (a2) obtained by adding ethylene oxide to compound (x) having a hydroxyl group, and fatty acid ester of polyoxyethylene compound (a2) ( An additive for coated paper, comprising at least one (a) selected from the group consisting of a3) and a fatty acid (b).
(2) Addition for coated paper according to (1), wherein the compound (x) having a hydroxyl group is at least one selected from the group consisting of polypropylene glycol, glycerin, diglycerin, pentaerythritol and trimethylolpropane. Agent.
(3) The fatty acid (b) is one or more selected from the group consisting of a fatty acid having 12 to 20 carbon atoms and having a hydroxyl group in the molecule and a dimer to decamer obtained by ester bonding of these fatty acids. The additive for coated paper according to the above (1) or (2).
(4) The oxazoline group-containing polymer (c) obtained by using a monomer having an ethylenic double bond having styrene, a (meth) acrylic acid ester and an oxazoline group as an essential monomer component (1) The additive for coated papers in any one of-(3).
In the present invention, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester.
(5) The coated paper according to (4), wherein the oxazoline group-containing polymer (c) is a copolymer (c1) of styrene, acrylic acid ester, 2-isopropenyl-2-oxazoline and divinylbenzene. Additive.
(6) The additive for coated paper according to any one of (1) to (5), which contains at least one (d) selected from the group consisting of polyethylene, polyethylene oxide, lanolin alcohol, and lanolin ester as a wax component. Agent.

(7) A paper coating comprising the pigment (A), the polymer binder (B), and the additive (C) for coated paper according to any one of (1) to (6). liquid.
(8) A coated paper obtained by applying a paper coating solution to the surface of a base paper for coating, wherein the paper coating solution comprises a pigment (A), a polymer binder (B) and the above (1) A coated paper comprising the coated paper additive (C) according to any one of to (6).

  According to the present invention, an additive for coated paper is added to a paper coating solution, and when the paper coating solution is applied to the surface of the base paper for coating, a paper coating solution with an increased amount of calcium carbonate is added. Good glossiness can be imparted even in situations where it is difficult to obtain glossiness, such as when used or bulky paper is used for coating, and it does not adversely affect high shear viscosity, releasability, printability, etc. There is an effect.

  Hereinafter, the additive for coated paper of the present invention, the paper coating solution containing this additive, and the coated paper obtained by coating this coating solution will be described in detail.

  The additive for coated paper of the present invention comprises the following (a) component and the following (b) component as essential active ingredients, and if necessary, together with these (a) and (b) components, It also contains the component (c) and / or the following component (d). In particular, it is preferable to contain at least component (c) among components (c) and (d), which are optional components.

Component (a): Polyethylene glycol (a1) having a number average molecular weight of 500 to 50,000, a polyoxyethylene compound (a2) obtained by adding ethylene oxide to a compound (x) having a hydroxyl group, and fatty acids of the polyoxyethylene compound (a2) At least one selected from the group consisting of esters (a3).
(B) Component: Fatty acid.
(C) Component: An oxazoline group-containing polymer obtained by using a monomer having an ethylenic double bond having styrene, (meth) acrylic acid ester and oxazoline group as an essential monomer component.
(D) Component: At least one selected from the group consisting of polyethylene, polyethylene oxide, lanolin alcohol and lanolin ester.

  The polyethylene glycol (a1) used as the component (a) has a number average molecular weight of 500 to 50,000, and preferably has a number average molecular weight of 1,000 to 30,000.

  The polyoxyethylene compound (a2) used as the component (a) is obtained by adding ethylene oxide (EO) to the compound (x) having a hydroxyl group. Here, as the compound (x) having a hydroxyl group, for example, monohydric alcohols (methanol, ethanol, isopropyl alcohol, t-butyl alcohol, octyl alcohol, dodecyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, etc.) , Polyhydric alcohols (ethylene glycol, propylene glycol, polypropylene glycol, hexylene glycol, dimethylolpropionic acid, glycerin, diglycerin, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol, sucrose, etc.), monohydric phenol (Phenol, cresol, ethylphenol, isobutylphenol, nonylphenol, etc.), polyhydric phenols (hydroquinone, catechol) Etc.), bisphenols (bisphenol A, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol S), as well as water. Among these, one or more selected from the group consisting of polypropylene glycol, glycerin, diglycerin, pentaerythritol, and trimethylolpropane is particularly preferable.

  The number of moles of ethylene oxide (EO) added in the polyoxyethylene compound (a2) is not particularly limited, but is preferably 3 to 300 moles, more preferably 8 to 200 moles.

  The ester (a3) used as the component (a) is a fatty acid ester of the polyoxyethylene compound (a2). Here, there is no restriction | limiting in particular as a fatty acid used for formation of ester, What has a linear structure or a branched structure is mentioned, You may have an unsaturated bond and a hydroxyl group in a molecule | numerator. Moreover, carbon number of this fatty acid is 6-22 normally, Preferably it is good that it is 10-20.

  Examples of the fatty acid used as the component (b) include those having a linear structure or a branched structure, and may have an unsaturated bond or a hydroxyl group in the molecule. Moreover, carbon number of this fatty acid is 6-22 normally, Preferably it is good that it is 12-20. Furthermore, among the fatty acids having 12 to 20 carbon atoms, those having a hydroxyl group in the molecule are more preferred, and dimer to 10-mers obtained by ester bonding of fatty acids having this hydroxyl group are also more preferred.

The component (c) is an optional component contained as necessary, but when the component (c) is also contained, the releasability is remarkably improved and the coated paper peels off from the calendar. The effect of significantly reducing the load is obtained. Further, by including the component (c), printability (mainly wet topic strength) can be improved.
The oxazoline group-containing polymer (c) used as the component (c) is obtained by using a monomer having an ethylenic double bond having styrene, a (meth) acrylic acid ester and an oxazoline group as an essential monomer component. It is a polymer. There are no particular restrictions on the various conditions such as the ratio of the monomer components and the polymerization method in obtaining the polymer (c), which may be set as appropriate. As a specific example of the polymer (c), a copolymer (c1) of styrene, acrylic acid ester, 2-isopropenyl-2-oxazoline and divinylbenzene is preferably exemplified. Specifically, the copolymer (c1) may be one obtained at an arbitrary copolymerization ratio, and the number average molecular weight is not limited, but it is usually 5 million to 25 million. As a commercial item of such a copolymer (c1), Nippon Shokubai Co., Ltd. "Epocross (registered trademark) K-2020E" etc. are mentioned.

The component (d) is an optional component contained as necessary, but the effect that the printability (mainly wet pick strength) can be further improved by including the component (d). Is obtained.
The component (d) is used as a wax component and is at least one selected from the group consisting of polyethylene, polyethylene oxide, lanolin alcohol, and lanolin ester, and among them, polyethylene and lanolin ester are particularly preferable. Examples of commercially available polyethylene wax include “Cretex PN-140” manufactured by Nisshin Chemical Laboratory, and examples of commercially available lanolin esters include “Lanoline Wax H” manufactured by Nippon Seika Co., Ltd. Is mentioned.

  The mixing ratio of the component (a) and the component (b) is not particularly limited, but the component (a) / component (b) (weight ratio) is preferably 90 to 10/10 to 90, and more preferably. Is preferably 80-20 / 20-80. When the component (a) is more than the above range, the printability may be deteriorated. On the other hand, when it is less than the above range, sufficient glossiness cannot be obtained.

When the component (c) is contained, the blending amount thereof is preferably 10 to 30 parts by weight, more preferably 15 parts per 100 parts by weight of the total amount of the component (a) and the component (b). It should be ˜20 parts by weight.
When the component (d) is contained, the blending amount is preferably 25 to 50 parts by weight, more preferably 35 parts per 100 parts by weight of the total amount of the components (a) and (b). It should be ˜40 parts by weight.
The mixing ratio of the component (c) and the component (d) is not particularly limited, but the component (c) / component (d) (weight ratio) is preferably 1 to 99 / 99-1. The total amount of the component (c) and the component (d) is preferably 10 to 80 parts by weight, more preferably 100 parts by weight of the total amount of the components (a) and (b). There should be 15-60 parts by weight.

  The additive for coated paper of the present invention is prepared by dissolving or dispersing (emulsifying) the components (a) and (b) and, if necessary, the components (c) and / or (d) in water. ). When obtaining the coated paper additive of the present invention, various surfactants may be added as an emulsifier or an organic solvent may be added as necessary. Further, when foaming occurs during production, an antifoaming agent can be added. The total concentration of the components (a) to (d) added to water is preferably about 5 to 50% by weight.

Next, the paper coating solution of the present invention will be described.
The paper coating solution of the present invention contains the pigment (A), the polymer binder (B), and the above-described additive for coated paper (C) of the present invention as essential components in an aqueous medium.
The pigment (A) is not particularly limited, and those conventionally used for coated paper, for example, calcium carbonate, kaolin, talc, titanium oxide, silica, zinc oxide, aluminum hydroxide and the like are used. it can. These pigments (A) may be used alone or in combination of two or more. The blending amount of the pigment (A) is not particularly limited, and may be appropriately set within a range of 35 to 65% by weight with respect to the total amount of the paper coating solution.

  There is no restriction | limiting in particular as said polymer binder (B), What is necessary is just to select arbitrarily from the synthetic polymer compounds and natural polymer compounds conventionally used for the normal paper coating liquid. For example, styrene / butadiene copolymer, styrene / vinyl acetate copolymer, styrene / acrylic copolymer, vinyl acetate / acrylic copolymer, butadiene / methyl methacrylate copolymer, vinyl acetate / butyl acrylate Copolymer, styrene / maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer, oxidized starch, esterified starch, urea phosphate esterified starch, etherified starch, enzyme-modified starch, casein, soybean Examples include proteins. These polymer binders (B) may be used alone or in combination of two or more. In general, these polymer binders (B) are preferably used in the form of an emulsion or a solution. Although the compounding quantity of a polymer binder (B) is not restrict | limited in particular, It is 3-30 weight part normally with respect to 100 weight part of pigments (A), Preferably it is 4-20 weight part.

  In the paper coating solution of the present invention, the amount of the additive for coated paper (C) is not particularly limited, but is usually 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the pigment (A), Preferably it is 0.5-2.0 weight part.

  In the paper coating solution of the present invention, if necessary, in addition to the essential components (A) to (C), a pH adjusting ammonia water, a dispersant such as sodium polyacrylate, and a release agent (for example, In addition, commercially available products such as “DEF-783TF” manufactured by Nissin Chemical Laboratory Co., Ltd.), various additives such as antifoaming agents, water retaining agents, preservatives, water-proofing agents, and the like within a range not impairing the effects of the present invention. It may be added.

  In the paper coating solution of the present invention, the components (A), (B), and (C) and various components added as necessary are added at predetermined ratios so as to be uniform. It can be prepared by sufficiently mixing and dispersing. The total solid concentration of the paper coating solution of the present invention thus obtained is preferably in the range of 40 to 70% by weight.

  The coated paper of the present invention is not only a conventional paper substrate (coating base paper) such as high-quality paper, medium-size paper, and paperboard, but also a paper substrate such as a lighter bulky paper that has been attracting attention in recent years ( It can be obtained by coating the paper coating solution of the present invention on one or both sides of the coating base paper. The coating method is not particularly limited, and for example, a known method using a blade coater, a roll coater, an air knife coater, a rod coater, a curtain coater, or the like can be adopted. What is necessary is just to set suitably.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example.
The physical properties of the paper coating solution and coated paper in each example were determined according to the following methods.

<Low Shear Viscosity of Paper Coating Liquid> A low shear viscosity at 25 ° C. was measured at a rotation speed of 60 rpm using a B-type viscometer.
<High Shear Viscosity of Paper Coating Liquid> Using a high shear viscometer, the high shear viscosity at 25 ° C. was measured at a rotational speed of 8800 rpm.
<Releasability> A test paper was prepared by applying and drying a paper coating solution on one side of a commercially available high-quality paper (basis weight 64 g / m ² ) so that the solid content was 22 g / m ^2. Wet the coated surface with water using a No. 3 bar coater, match the aluminum foil on the coated surface, and then pass once through a mini super calender under the conditions of 6.0 m / min, 100 ° C., 150 kg / cm, A test paper with an aluminum foil attached thereto was prepared. The prepared test paper is cut into strips (3 cm × 20 cm) to prepare 5 samples, and each sample is measured with an adhesive strength tester (“HEIDON-17 type” manufactured by Shinto Kagaku Co., Ltd.). The load (g / 3 cm) was measured while pulling the coated surface and the aluminum foil at a speed of 5 mm / sec. Next, the degree of soiling of the peeled aluminum foil was visually observed, and evaluated with numerical values of “1” to “5” based on the following criteria (the larger the numerical value, the better without contamination). In addition, the evaluation result of the load and the soiling condition of the aluminum foil was expressed as an average value of five samples.
5: No dirt is observed on the surface of the aluminum foil, and the surface is clean 4: Very little dirt is observed on the surface of the aluminum foil, but there is no influence on the calendar processing. 3: On the surface of the aluminum foil Slight dirt is observed, but it does not affect the calendar process. 2: A large number of dirt is observed on the aluminum foil surface to the extent that there is a concern about the adverse effect of the calendar process. 1: The entire aluminum foil surface is dirty. There is a strong concern about the negative effects of the calendar process. <Glossiness of coated paper> According to JIS-P8142-1965, the glossiness of white paper is measured at 75 °, and the glossiness of printing is The 60 ° gloss was measured.
<Whiteness of coated paper> Measured according to JIS-P813-1961.
<Dry pick strength and wet topic strength of coated paper> Using the RI-II type printability tester (manufactured by Meisei Seisakusho Co., Ltd.), printing is performed on the surface of the coated paper, and picking occurs at 5 points (5 locations). The situation was visually observed, and evaluated with numerical values of “1” to “5” based on the following criteria (the larger the numerical value, the less the occurrence of picking), and the average value of 5 points.
5: No drop-off coating layer is observed on the surface of the coated paper 4: A slight drop-off coating layer is observed on the surface of the coated paper, but the possibility of adversely affecting printing is extremely low 3: Coating A slight drop-off coating layer is observed on the surface of the paper, but the possibility of adversely affecting printing is low. 2: Slightly more drop-off coating on the surface of the coated paper to the extent that there is a concern about adverse effects on printing Layers are recognized 1: Many falling coating layers are observed on the surface of the coated paper, and the possibility of adversely affecting printing is extremely high

(Example 1-1)
T.A. K. In an agitator equipped with an azihomomicr (manufactured by Primix Co., Ltd.), 25.63 parts by weight of polyethylene glycol having a number average molecular weight of 20,000 and 12-hydroxyoctadecanoic acid hexamer (“K-PON306” manufactured by Ogura Gosei Kogyo Co., Ltd.) 5.13 parts by weight, 3.42 parts by weight of 12-hydroxy-cis-9-octadecenoic acid (manufactured by Ogura Gosei Kogyo Co., Ltd.), 1.42 parts by weight of emulsifier (1) (polyoxyethylene polyoxypropylene decyl ether) , 1.14 parts by weight of emulsifier (2) (polyoxyethylene distyrenated phenyl ether) and 4.73 parts by weight of emulsifier (3) (polyoxyethylene polycyclic phenyl ether sulfate: solid content 30% by weight) 1.42 parts by weight in terms of minutes) was added and completely dissolved while stirring at 70 to 80 ° C. To this, 58.54 parts by weight of water kept at 70 to 80 ° C. was added little by little to cause phase inversion emulsification to form an O / W emulsion, and then returned to room temperature and stirred for 30 minutes. An additive (1) for coated paper was obtained.

(Example 1-2)
In Example 1-1, the additive for coated paper was prepared in the same manner as in Example 1-1, except that 100 mol of diglycerin / ethylene oxide adduct was used instead of polyethylene glycol having a number average molecular weight of 20000. (2) was obtained.

(Example 1-3)
In Example 1-1, except that a pluronic surfactant (“Adeka Pluronic F88” manufactured by Asahi Denka Kogyo Co., Ltd.) was used instead of polyethylene glycol having a number average molecular weight of 20000, the same as Example 1-1 Thus, an additive for coated paper (3) was obtained.

(Example 1-4)
In Example 1-1, an additive for coated paper was prepared in the same manner as in Example 1-1, except that 20 mol of pentaerythritol / ethylene oxide adduct was used instead of polyethylene glycol having a number average molecular weight of 20000. (4) was obtained.

(Example 1-5)
In Example 1-1, the addition for coated paper was performed in the same manner as in Example 1-1, except that a 20-methyl trimethylolpropane / ethylene oxide adduct was used instead of polyethylene glycol having a number average molecular weight of 20000. Agent (5) was obtained.

(Example 1-6)
In Example 1-1, coating was performed in the same manner as in Example 1-1 except that monostearic acid ester of 40 mol diglycerin / ethylene oxide adduct was used instead of polyethylene glycol having a number average molecular weight of 20000. Paper additive (6) was obtained.

(Example 1-7)
T.A. K. In a stirring vessel equipped with an azihomomicr (manufactured by Primix Co., Ltd.), 1.04 parts by weight of polyethylene glycol having a number average molecular weight of 20,000, 6.48 parts by weight of monostearate ester of 40 mol of diglycerin / ethylene oxide, 12- Hydroxyoctadecanoic acid hexamer (“K-PON306” manufactured by Ogura Gosei Kogyo Co., Ltd.) 19.44 parts by weight, 6.48 parts by weight of 12-hydroxy-cis-9-octadecenoic acid (Ogura Gosei Kogyo Co., Ltd.) , Emulsifier (1) (polyoxyethylene polyoxypropylene decyl ether) 1.30 parts by weight, emulsifier (2) (polyoxyethylene distyrenated phenyl ether) 1.04 parts by weight, emulsifier (3) (polyoxyethylene poly Ring phenyl ether sulfate ester: solid content 30% by weight) 4.30 parts by weight (in terms of solid content) .29 parts by weight) and antifoam (Dow Corning Asia Co., Ltd. "2-4248S") were added 0.10 part by weight, was completely dissolved with stirring at 70 to 80 ° C.. To this, 45.62 parts by weight of water kept at 70 to 80 ° C. was added little by little to cause phase inversion emulsification to produce an O / W emulsion, and then the liquid temperature was returned to room temperature and stirred for 30 minutes. To this, an emulsion of an oxazoline group-containing polymer (“Epocross K-2020E” manufactured by Nippon Shokubai Co., Ltd .: 40 wt% solid content) 14.20 parts by weight (5.68 parts by weight in terms of solid content) was added, and 30 at room temperature was added. The mixture was stirred for a minute to obtain a coated paper additive (7).

(Example 1-8)
In Example 1-7, except that stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of 12-hydroxy-cis-9-octadecenoic acid (manufactured by Ogura Gosei Kogyo Co., Ltd.), Example Coated paper additive (8) was obtained in the same manner as in 1-7.

(Example 1-9)
In Example 1-7, except that oleic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of 12-hydroxy-cis-9-octadecenoic acid (manufactured by Ogura Gosei Kogyo Co., Ltd.), Example Coated paper additive (9) was obtained in the same manner as in 1-7.

(Example 1-10)
T.A. K. In a stirring vessel equipped with an azihomomicr (manufactured by Primix Co., Ltd.), 0.75 parts by weight of polyethylene glycol having a number average molecular weight of 20,000, 4.68 parts by weight of monostearate ester of 40 mol of diglycerin / ethylene oxide, 12- Hydroxyoctadecanoic acid hexamer (“K-PON306” manufactured by Ogura Gosei Kogyo Co., Ltd.) 13.98 parts by weight, 12-hydroxy-cis-9-octadecenoic acid (Ogura Gosei Kogyo Co., Ltd.) 4.68 parts by weight , Emulsifier (1) (polyoxyethylene polyoxypropylene decyl ether) 0.95 parts by weight, emulsifier (2) (polyoxyethylene distyrenated phenyl ether) 0.75 parts by weight, emulsifier (3) (polyoxyethylene poly Ring phenyl ether sulfate: solid content 30% by weight) 3.09 parts by weight (in terms of solid content) .93 parts by weight) and antifoam (Dow Corning Asia Co., Ltd. "2-4248S") were added 0.07 part by weight, was completely dissolved with stirring at 70 to 80 ° C.. To this, 32.84 parts by weight of water kept at 70 to 80 ° C. was added little by little to cause phase inversion emulsification to produce an O / W emulsion, and then the liquid temperature was returned to room temperature and stirred for 30 minutes. To this, an emulsion of an oxazoline group-containing polymer (“Epocross K-2020E” manufactured by Nippon Shokubai Co., Ltd .: solid content 40% by weight) 10.23 parts by weight (4.09 parts by weight in terms of solids) and a polyethylene wax emulsion (( “Cretex PN-140” manufactured by Nissin Chemical Laboratory Co., Ltd .: 28.0 parts by weight (solid content: 40% by weight) (11.20 parts by weight in terms of solid content) was added and stirred at room temperature for 30 minutes. Thus, an additive (10) for coated paper was obtained.

(Example 1-11)
T.A. K. In an agitator equipped with an azihomomicr (manufactured by Primix Co., Ltd.), 0.75 parts by weight of polyethylene glycol having a number average molecular weight of 20,000, 4.68 parts by weight of monostearate ester of 40 mol of diglycerin / ethylene oxide, 12- Hydroxyoctadecanoic acid hexamer (“K-PON306” manufactured by Ogura Gosei Kogyo Co., Ltd.) 13.98 parts by weight, 12-hydroxy-cis-9-octadecenoic acid (Ogura Gosei Kogyo Co., Ltd.) 4.68 parts by weight , Lanolin ester (Nippon Seika Co., Ltd. "lanolin wax H") 11.20 parts by weight, emulsifier (1) (polyoxyethylene polyoxypropylene decyl ether) 0.95 parts by weight, emulsifier (2) (polyoxy 0.75 parts by weight of ethylene distyrenated phenyl ether), emulsifier (3) (polyoxyethylene polycycle) (Ethyl ether sulfate ester: solid content 30% by weight) 3.09 parts by weight (0.93 parts by weight in terms of solid content) and antifoaming agent (“2248S” manufactured by Dow Corning Asia Ltd.) 0.07 parts by weight Was completely dissolved with stirring at 70-80 ° C. To this, 49.64 parts by weight of water kept at 70 to 80 ° C. was added little by little to cause phase inversion emulsification to produce an O / W emulsion, and then the liquid temperature was returned to room temperature and stirred for 30 minutes. To this was added 10.23 parts by weight (4.09 parts by weight in terms of solids) of an oxazoline group-containing polymer emulsion (“Epocross K-2020E” manufactured by Nippon Shokubai Co., Ltd .: 40% by weight solids), and 30 at room temperature. The mixture was stirred for a while to obtain a coated paper additive (11).

(Comparative Example 1-1)
Polyethylene glycol having a number average molecular weight of 20,000 was used as a comparative additive (C1).

(Examples 2-1 to 2-11 and Comparative Examples 2-1 to 2-2 (Prescription I: Conventional formulation))
60 parts by weight of commercially available primary kaolin (UW-90), 40 parts by weight of heavy calcium carbonate ("Carbital (registered trademark) 90" manufactured by Imeris) (as solid content), commercially available styrene / butadiene copolymer latex 10 Parts by weight, urea phosphate esterified starch (“MS-4600” manufactured by Nippon Shokuhin Kako Co., Ltd.) 4 parts by weight, dispersant (“NSD-300” manufactured by Nissin Chemical Laboratory Co., Ltd.) 0.2 parts by weight (As solids), 0.05 parts by weight of sodium hydroxide (as solids) are mixed, water is added so that the total solids concentration becomes 60% by weight, and then a water-resistant agent (Sumitomo Chemtex Co., Ltd.) ) “Sumirez Resin (registered trademark) SPI-203”: 50% modified polyacrylamide resin) 0.3 parts by weight (solid content with respect to pigment components (primary kaolin and heavy calcium carbonate)) 0.3% by weight), adjust the pH to 9.2 with 28% aqueous ammonia, and then add 1.0 part by weight of the additive for coated paper obtained above until uniform. By mixing, the paper coating solutions (2-1) to (2-11) and (2-C1) of Formula I were obtained.
On the other hand, as a blank, a paper coating solution (2-C2) of Formula I was obtained in the same manner as above except that none of the coating paper additives was added.

Next, the obtained paper coating solution was applied and dried on one side of a commercially available high-quality paper (basis weight 64 g / m ² ) so that the solid content was 22 g / m ^2, and then super calendered under predetermined conditions. Processing was performed to prepare coated paper. There are two conditions for supercalender treatment: (i) conventional coated paper specifications; temperature 70 ° C., linear pressure 100 kg / cm, and (ii) bulky coated paper specifications; temperature 70 ° C., linear pressure 25 kg / cm. (However, the linear pressure corresponds to the roll pressure in the actual coating machine).
Table 1 shows the measurement results of physical properties and releasability of each paper coating solution, and Table 2 shows the measurement results of physical properties and printability of each coated paper when the conventional coated paper specifications are used. ) Table 3 shows the measurement results of the physical properties and printability of each coated paper when bulky coated paper is used.

(Examples 3-1 to 3-11 and Comparative Examples 3-1 to 3-2 (Prescription II: calcium carbonate increase prescription))
30 parts by weight of commercially available primary kaolin (UW-90), 70 parts by weight of heavy calcium carbonate (“Carbital 90” manufactured by Imeris) (as solids), 10 parts by weight of commercially available styrene / butadiene copolymer latex, urea Phosphate esterified starch (“MS-4600” manufactured by Nippon Food Processing Co., Ltd.) 4 parts by weight, dispersant (“NSD-300” manufactured by Nissin Chemical Laboratory Co., Ltd.) 0.2 parts by weight (as solid content) ), 0.05 parts by weight of sodium hydroxide (as solids), and water was added so that the total solids concentration was 60% by weight. Then, a water-resistant agent (“Sumirez manufactured by Sumitomo Chemtex Co., Ltd.) was added. Resin SPI-203 ": modified polyacrylamide resin 50% product) 0.3 parts by weight (solid content 0.3% by weight with respect to pigment components (primary kaolin and heavy calcium carbonate)) After adjusting the pH to 9.2 with 28% ammonia water, add 1.0 part by weight of the additive for coated paper obtained above and mix until uniform, thereby applying the paper coating of Formula II. Industrial fluids (3-1) to (3-11) and (3-C1) were obtained.
On the other hand, as a blank, a paper coating solution (3-C2) of Formula II was obtained in the same manner as above except that none of the coating paper additives was added.

Next, the obtained paper coating solution was applied and dried on one side of a commercially available high-quality paper (basis weight 64 g / m ² ) so that the solid content was 22 g / m ^2, and then super calendered under predetermined conditions. Processing was performed to prepare coated paper. There are two conditions for supercalender treatment: (i) conventional coated paper specifications; temperature 70 ° C., linear pressure 100 kg / cm, and (ii) bulky coated paper specifications; temperature 70 ° C., linear pressure 25 kg / cm. (However, the linear pressure corresponds to the roll pressure in the actual coating machine).
Table 4 shows the measurement results of physical properties and releasability of each paper coating solution, and Table 5 shows the measurement results of physical properties and printability of each coated paper when the conventional coating paper specifications are used. ) Table 6 shows the measurement results of physical properties and printability of each coated paper when bulky coated paper is used.

  From the above results, all of the paper coating liquids containing the additive for coated paper of the present invention are specified in bulky coated paper specifications where it is difficult to obtain gloss, and the formulation of the paper coating liquid with an increased amount of calcium carbonate. It can also be seen that good white paper gloss and printing gloss are imparted. In addition, the coating paper additive of the present invention does not adversely affect the physical properties, releasability, and printability (dry pick strength and wet topic strength) of the paper coating solution, so that good coating and printing are possible. It was also confirmed that can be realized.

Claims (8)

  Polyethylene glycol (a1) having a number average molecular weight of 500 to 50,000, a polyoxyethylene compound (a2) obtained by adding ethylene oxide to a compound (x) having a hydroxyl group, and a fatty acid ester (a3) of the polyoxyethylene compound (a2) An additive for coated paper, comprising at least one (a) selected from the group consisting of: a fatty acid (b).   The additive for coated paper according to claim 1, wherein the compound (x) having a hydroxyl group is at least one selected from the group consisting of polypropylene glycol, glycerin, diglycerin, pentaerythritol and trimethylolpropane.   The fatty acid (b) has 12 to 20 carbon atoms, and is at least one selected from the group consisting of a fatty acid having a hydroxyl group in the molecule and a 2 to 10 mer obtained by ester bonding of these fatty acids. The additive for coated paper according to claim 1 or 2.   The oxazoline group-containing polymer (c) obtained by using, as an essential monomer component, a monomer having an ethylenic double bond having styrene, a (meth) acrylic acid ester and an oxazoline group, Additive for coated paper according to crab.   The additive for coated paper according to claim 4, wherein the oxazoline group-containing polymer (c) is a copolymer (c1) of styrene, acrylic acid ester, 2-isopropenyl-2-oxazoline and divinylbenzene.   The additive for coated paper according to any one of claims 1 to 5, comprising at least one (d) selected from the group consisting of polyethylene, polyethylene oxide, lanolin alcohol and lanolin ester as a wax component.   A paper coating solution comprising the pigment (A), the polymer binder (B), and the additive (C) for coated paper according to any one of claims 1 to 6.   A coated paper obtained by coating a paper coating solution on the surface of a base paper for coating, wherein the paper coating solution is a pigment (A), a polymer binder (B), or any one of claims 1 to 6. A coated paper comprising the additive for coated paper (C) according to any one of the above.