JP5868647B2 - Coated paper and water-repellent paper - Google Patents

Description

  The present invention relates to a coated paper and a water-repellent paper for self-repellent treatment.

  Many packaging papers (including paperboard) require water repellency in consideration of water adhesion. In such cases, water-repellent paper coated with a water-repellent agent is used. Is done. The application of the water repellent agent may be performed consistently with papermaking or the like in a paper mill, but may also be performed at a place different from the paper mill, which is referred to as so-called self-water repellent treatment. Specific examples of the self-water-repellent treatment include those that are performed consistently with the pasting or the like at the time of pasting by a corrugator in a corrugated cardboard processing factory.

  Water-repellent processed products obtained by consistently performing water-repellent processing with papermaking etc. may cause a decrease in water repellency due to heating during the papermaking stage drying process or overheating during corrugating at a corrugated board processing company. Therefore, it is necessary to provide in advance an excessive water repellency in anticipation of a decrease in water repellency. For this reason, the water-repellent processed product causes problems such as a decrease in productivity and poor processing during corrugator processing due to excessive water repellency. Water treatment is deeply used.

  The paper used for the above-mentioned self-water repellent treatment has good surface fixability of the water repellent to the surface when the water repellent is applied, and is excellent in the formation of a film made of the water repellent. Is required to have a strength that can withstand processing by a corrugator. When base paper that has not been surface-treated is used for self-water-repellent applications, the self-water-repellent agent is excessively impregnated on the surface of the base paper, resulting in poor water-repellent effect and a large amount of water to bring out water repellency. Inconvenience arises in that a water repellent must be provided on the surface of the base paper. In addition, when the strength of the paper surface is not sufficient, there is a disadvantage that surface cracking or thermal degradation occurs when corrugator processing is performed.

  Here, as a technique relating to paper for the purpose of improving water repellency, a technique of applying a specific resin or water repellent to the surface has been proposed (Japanese Patent Laid-Open No. 9-310297, Japanese Patent Laid-open No. 7-26495 and JP-A-2005-200772). However, these are merely techniques for increasing the water repellency of paper, and do not satisfy the above-described characteristics required for the paper used for the above-mentioned self-water-repellent treatment.

Japanese Patent Laid-Open No. 9-310297 Japanese Patent Laid-Open No. 7-26495 Japanese Patent Laying-Open No. 2005-200772

  The present invention has been made on the basis of the above-described circumstances, and is excellent in film-forming property when applying a water repellent to the surface, and has a high surface strength and is used for self-water repellent treatment. An object is to provide a craft paper and a water-repellent paper obtained from such a coated paper.

The invention made to solve the above problems is
It is a coated paper for self-repellent treatment in which a coating liquid is coated on the surface of the base paper,
The base paper is an acidic paper with a rosin sizing agent added internally,
The coating liquid includes a cationic styrene resin, an acrylamide resin, and a vinyl alcohol polymer.

  Since the coating liquid used for the coated paper contains a cationic styrene resin, the surface of the coated paper is made cationic by the coating of the coating liquid. Further, the water repellent applied during the self-water repellent treatment has an anionic property. Therefore, according to the coated paper, due to the electrical affinity, the fixing property of the water repellent to the surface is high, and the formability of the film made of the water repellent is excellent. Moreover, since the coated paper used for the coated paper contains an acrylamide resin and a vinyl alcohol polymer, the surface strength of the coated paper is high. Furthermore, since the base paper of the coated paper is an acidic paper with a rosin sizing agent added internally, the coating liquid is unlikely to penetrate into the base paper, and the above components tend to remain on the surface. The reason for this is not clear, but in addition to the effect of the sizing agent, the base paper is catalytically functioning, and the crosslinking reaction of each resin contained in the coating liquid can easily proceed. It is conceivable that penetration into the paper is reduced. Therefore, according to the coated paper, paper having high water repellency can be obtained by the self-water repellent treatment.

  The vinyl alcohol polymer preferably has an average degree of polymerization of 1,200 to 2,200 and a saponification degree of 97% or more. According to the coated paper, by using a vinyl alcohol polymer having a polymerization degree and a saponification degree within the above ranges, film formability and surface strength can be further increased.

The base paper has two or more pulp fiber layers, and the basis weight of the first pulp fiber layer (hereinafter sometimes referred to as “surface layer”) located on the surface is 15 g / m ² or more and 35 g / m ² or less. There should be. When the coated paper has such a thin surface layer, a part of the coating liquid set so as not to penetrate into the base paper can be soaked into the second pulp fiber layer laminated on the inside of the surface layer. Therefore, according to the coated paper, due to the anchor effect of the resin or the like contained in the coating liquid, the strength between the first pulp fiber layer and the second pulp fiber layer is increased, and as a result, the surface strength is further increased. Can do.

  The coated paper may further include a starch layer formed between the first pulp fiber layer and a second pulp fiber layer laminated inside the first pulp fiber layer. Due to the starch layer, the first pulp fiber layer and the second pulp fiber layer are brought into close contact with each other, and further, the first pulp fiber is obtained by an anchor effect due to penetration of the resin or the like contained in the coating liquid into the starch layer. The strength between the layer and the second pulp fiber layer can be further increased. Moreover, since the penetration of the coating liquid can be stopped in the vicinity of the starch layer, the coating liquid component remains in the vicinity of the surface, and as a result, the film forming property of the water repellent can be enhanced.

The first pulp fiber layer may be formed by papermaking of a pulp slurry containing a rosin-based sizing agent in a solid content concentration of 6 kg / t or more and 12 kg / t or less. By doing in this way, the size property of a surface layer can be improved, and at the time of coating of a coating liquid, the penetration | infiltration to components after the 2nd pulp fiber layer of components, such as resin in a coating liquid, is made into an appropriate quantity. Can be controlled. Therefore, according to the said coating liquid, the film formation property and intensity | strength in the case of a self-water-repellent process can be improved more.

  The water repellent paper of the present invention is obtained by coating an anionic water repellent on the surface of the coated paper. Since the water-repellent paper has high fixability of the water-repellent agent on the surface, it can exhibit excellent water repellency.

  Here, the self-water repellent treatment refers to a treatment for imparting water repellency to the surface of the paper obtained in the paper mill at a place different from the paper mill. The average degree of polymerization refers to the viscosity average degree of polymerization measured according to JIS-K6726. The saponification degree is a value measured according to JIS-K6726. The basis weight of the surface layer means a value measured according to JIS-P8124 with respect to the surface layer peeled for each layer.

  As described above, the coated paper of the present invention is excellent in film formation by applying a water repellent to the surface and has high surface strength. An aqueous paper can be obtained.

  Hereinafter, embodiments of the coated paper and the water-repellent paper of the present invention will be described in detail.

<Coated paper>
The coated paper of the present invention is a coated paper for self-repellent treatment in which a coating liquid containing a specific resin component is coated on the surface of a base paper.

(Base paper)
The base paper is acid paper. By using such a base paper, the coating liquid described in detail later hardly penetrates into the base paper, and each component in the coating liquid tends to remain on the surface. The reason for this is not clear, but acidity of the base paper functions as a catalyst, and the cross-linking reaction of each resin contained in the coating solution is likely to proceed, thereby reducing penetration into the base paper. Can be considered.

  Acid paper refers to paper having a paper surface pH of less than 7. Further, the paper surface pH of the base paper is preferably 5 or more and less than 7, for example. Note that the pH of the paper surface is J.P. TAPPI paper pulp test method no. It is a value measured by the method specified in 6-75.

  The said base paper is formed by making the pulp slurry which has the pulp fiber which uses pulp as a raw material as a main component. The base paper may have a single-layer structure composed of one pulp fiber layer or a multilayer structure having two or more pulp fiber layers. From the viewpoint, a multilayer structure is preferable. In the case of a multilayer structure, the number of layers is preferably 3 or more and 7 or less, and more preferably 5 layers. Here, the pulp fiber layer refers to a layer formed by papermaking a pulp slurry mainly composed of pulp fibers.

  The pulp is not particularly limited. For example, waste paper pulp (DIP), chemical pulp (for example, hardwood kraft pulp: LBKP, softwood kraft pulp: NBKP, etc.), mechanical pulp (for example, thermomechanical pulp: TMP, pressured kraft) Pulp, PGW, refiner ground pulp: RGP, ground pulp, etc.) and non-wood pulp such as kenaf, bagasse, hemp, and cotton. Among these, it is preferable to use waste paper pulp.

  When the base paper has two or more pulp fiber layers, it is preferable to contain 60% by mass or more of waste paper pulp as the pulp forming the surface layer (first pulp fiber layer). Thus, by increasing the content ratio of the used paper pulp in the surface layer, the components of the coating liquid can be easily penetrated in the surface layer, the anchor effect of the coating liquid component can be enhanced, and a firm surface can be formed.

  When the base paper has two or more pulp fiber layers, the base paper further includes a starch layer formed between the surface layer and a second pulp fiber layer laminated inside the surface layer. Good. Due to the starch layer, the surface layer and the second pulp fiber layer are in close contact with each other, and the surface layer and the second pulp fiber layer are further anchored by the anchor effect caused by the penetration of the resin contained in the coating liquid into the starch layer. The strength between can be further increased. In addition, by providing such a starch layer, the penetration of the coating liquid can be stopped in the vicinity of this starch layer, so that the coating liquid component remains from the vicinity of the surface, resulting in the formation of a water repellent film. Can increase the sex. Furthermore, in order to enhance this effect, it is preferable that a starch layer is also formed between the second pulp fiber layer and the third pulp fiber layer laminated inside the second pulp fiber layer.

  A starch layer can be provided on the inner side of the third pulp fiber layer and further on the inner fiber layer. However, the formation of an excess starch layer will cause the resulting corrugated cardboard sheet to become harder and hinder box molding, or for bonding It is preferable to provide a starch layer inside the surface layer, the second pulp fiber layer, and the inside of the second pulp fiber layer.

  The base paper contains a rosin sizing agent as an internally added sizing agent. By using the rosin sizing agent, it is possible to effectively control the penetration of each component contained in the coating liquid. As rosin substances in the above rosin sizing agents, rosins such as gum rosin, wood rosin and tall oil rosin are modified with α, β-unsaturated carboxylic acids such as fumaric acid, maleic acid and acrylic acid or anhydrides thereof. Examples of rosin and rosin esters obtained by reacting the above rosins with polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and diglycerin can be mentioned. Can be used alone or mixed after being emulsified alone. Furthermore, what added various polymers to the said rosin emulsion in order to improve size developability can also be used.

The basis weight (attachment amount) of the surface layer is preferably 15 g / m ² or more and 35 g / m ² or less, more preferably 20 g / m ² or more and 30 g / m ² or less. Since the coated paper has such a thin surface layer, a part of the coating liquid set so as not to penetrate into the base paper can be soaked into the second pulp fiber layer. Therefore, according to the coated paper, the strength between the surface layer and the second pulp fiber layer can be increased by the anchor effect of the resin or the like contained in the coating liquid, and as a result, the surface strength can be further increased.

  The said surface layer is good to be formed by the papermaking of the pulp slurry which contains rosin-type sizing agent solid content concentration 6kg / t or more and 12kg / t or less. By doing so, the size of the surface layer can be increased, and when the coating liquid is applied, the penetration of components such as resins in the coating liquid into the second and subsequent layers is controlled to an appropriate amount. it can. Therefore, according to the said coating liquid, the film formation property and intensity | strength in the case of a self-water-repellent process can be improved more.

  The base paper may contain components other than the pulp fiber and the rosin sizing agent which is an internal sizing agent. Examples of other components include an internal sizing agent (for example, a synthetic polymer sizing agent) other than a sulfate band and a rosin sizing agent, a paper strength enhancer, a filler, and the like.

  The base paper can be obtained, for example, by subjecting a raw pulp slurry corresponding to each layer to multilayer paper making by a known method. Moreover, when providing a starch layer, it can form by spray injection of the liquid containing starch.

(Coating fluid)
The coating solution includes a cationic styrene resin, an acrylamide resin, and a vinyl alcohol polymer. Thus, since the coating liquid used for the coated paper contains a cationic styrene-based resin, the surface of the coated paper is made cationic by application of the coating liquid. Further, the water repellent applied during the self-water repellent treatment has an anionic property. Therefore, according to the coated paper, the film-forming property by the water repellent when applying the water repellent to the surface is excellent due to electrical affinity. Moreover, since the coated paper used for the coated paper contains an acrylamide resin and a vinyl alcohol polymer, the surface strength of the coated paper is high. Therefore, according to the coated paper, paper having high water repellency can be obtained by the self-water repellent treatment.

  The cationic styrene resin is not particularly limited as long as it is a cationic resin containing styrene as a monomer, and known ones can be used. Examples of commercially available cationic styrene resins include Size Pine W-360 and Polymeron 360 manufactured by Arakawa Chemical Industries.

  Examples of the acrylamide resins include acrylamide polymers, methacrylamide polymers, and acrylamide / methacrylamide copolymers. As said acrylamide resin, what is cationic is preferable. By using a cationic acrylamide-based resin, the cationic property of the surface of the coated paper to be obtained is further increased, and the film-forming property of the water-repellent agent on the surface is further increased. Further, by using a cationic acrylamide resin, the compatibility with the cationic styrene resin is increased, the surface strength is increased, and the permeation suppressing effect of the water repellent can be enhanced.

  Examples of the cationic acrylamide resin include resins obtained by polymerizing acrylamide or the like and cationic vinyl monomers. Examples of cationic vinyl monomers include vinyl monomers having a primary amino group (such as 2-propenylamine), vinyl monomers having a secondary amino group (such as di (2-propenyl) amine), and vinyl having a tertiary amino group. Monomers (N, N-dimethyl-2-properoyloxyethylamine, etc.), vinyl monomers having quaternary ammonium salts (N, N-dimethyl-N, N-di (2-propenyl) ammonium chloride, etc.), etc. be able to.

The vinyl alcohol polymer is a polymer having a vinyl alcohol unit (—CH ₂ —CHOH—) as a main structural unit. In addition, the said vinyl alcohol-type polymer may contain structural body units other than a vinyl alcohol unit.

  The average degree of polymerization of the vinyl alcohol polymer is preferably 1,200 to 2,200, more preferably 1,500 to 1,900. By using a vinyl alcohol polymer having such a degree of polymerization, the surface strength of the coated paper can be further increased. When the degree of polymerization is less than the above lower limit, the surface strength of the paper tends to decrease. On the other hand, when the degree of polymerization exceeds the above upper limit, the viscosity increases or the solubility decreases, resulting in a decrease in coatability and a decrease in surface strength. In addition, by using a vinyl alcohol polymer having such a degree of polymerization, the strength of the coating film (coating layer) itself containing three components of a cationic styrene resin, an acrylamide resin and a vinyl alcohol polymer can be increased. It is possible to increase the penetration inhibiting effect of the water repellent.

  The saponification degree of the vinyl alcohol polymer is preferably 97% or more, and more preferably 97.5% or more. By using a vinyl alcohol polymer having such a saponification degree, the surface strength of the coated paper can be further increased. The upper limit of the saponification degree of the vinyl alcohol polymer is not particularly limited, but is 99.9%, for example.

  Moreover, as a component contained in the coating solution, by using a vinyl alcohol polymer having the polymerization degree and saponification degree together with a cationic styrene resin and an acrylamide resin, the three components are uniformly dissolved, The strength can be increased without unevenness of the paper surface.

  The content ratio of the cationic styrene resin, acrylamide resin and vinyl alcohol polymer in the coating liquid is preferably 10: 8 to 10:15 to 25 in terms of solid content. By setting the three components to such a ratio, the film forming property and strength on the coated paper surface can be improved in a balanced manner.

  The coating liquid may contain other components in addition to the three components. Examples of the other components include other surface sizing agents, paper strength enhancers, water-soluble polymers, pigments, and other additives.

  The method for coating the coating liquid on the surface of the base paper is not particularly limited, and is a coating apparatus commonly used in the papermaking field, for example, a size press, a blade metering size press, a rod metering size press, a blade coater. , Bar coater, gate roll coater, rod coater, air knife coater and the like.

As the coating amount of the coating liquid, it is applied to the surface of the base paper in a dry mass of 0.1 to 1.0 g / m ² , and further 0.2 to 0.8 g / m ² . Is preferred. When it is less than 0.1 g / m ² , it is difficult to obtain a sufficient film, and there are cases where sufficient paper surface strength or water repellency cannot be obtained when subjected to self-water repellent treatment. On the other hand, if it exceeds 1.0 g / m ² , the peripheral device may be soiled, and the operability may be hindered such as an increase in cost and a decrease in drying property.

  After the coating liquid is applied and dried, the paper is passed through a calendar and subjected to pressure finishing. As the calendar device in this case, for example, various calenders such as a super calender, a gloss calender, a soft compact calender, or a combination of a drum and an elastic roll can be used as appropriate in an on-machine or off-machine specification.

(Quality etc.)
The basis weight of the coated paper is not particularly limited, but is preferably 100 g / m ² or more and 300 g / m ² or less, and more preferably 150 g / m ² or more and 260 g / m ² or less. By setting the basis weight within such a range, the coated paper can exhibit sufficient strength and the like. Here, the basis weight refers to a value measured according to JIS-P8124.

  The surface strength of the coated paper is preferably 10A or more, and more preferably 12A or more and 20A or less. By having such surface strength, the coated paper can suppress the occurrence of surface cracks, for example, when corrugator processing is performed. The surface strength is measured according to JAPAN TAPPI No. The value measured by the method specified in 1.

  Since the coated paper is excellent in film formation by applying a water repellent to the surface in this way, and the strength of the surface is high, a water-repellent paper having high water repellency can be obtained by self-water repellent treatment. Can do. Specifically, the coated paper is suitably used as a front liner or the like. When used as a front liner, a water repellent is applied to the surface as a self-water repellent treatment, for example, in a bonding step using a corrugator.

<Water repellent paper>
The water-repellent paper of the present invention is obtained by coating an anionic water-repellent agent on the surface of the coated paper by self-water-repellent treatment. The water-repellent paper can exhibit excellent water repellency.

  As said water repellent, if an anionic compound is included, it can be used without a restriction | limiting. Examples of such water repellents include waxes, synthetic resins, and mixtures thereof. As a commercial item of the said water repellent, RIPAX A-240 etc. by a modern chemical industry company etc. can be mentioned, for example.

The coating amount of the water repellent is not particularly limited, but is preferably 0.03 to 1.0 g / m ² , and more preferably 0.05 to 0.8 g / m ² . If the coating amount of the water repellent is less than 0.03 g / m ² , the water repellency may not be improved. On the other hand, if it exceeds 1.0 g / m ² , the slip angle may decrease. .

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In addition, the addition amount of various chemical | medical agents is the value of solid content conversion.

[Example 1]
(Manufacture of base paper)
As a raw material pulp for the first pulp fiber layer, a pulp containing 68% by mass of waste paper pulp was used. As pulp other than waste paper pulp, NBKP and LBKP were used at a mass ratio of 7: 3. For this raw material pulp, a weakly acidic internal sizing agent (Harsize NES-680 emulsion type rosin internal sizing agent manufactured by Harima Chemicals Co., Ltd.) (7 kg / t), sulfuric acid band (32 kg / t), paper (7 kg / t) of a power agent (Harmide TA-238 Cationic Polyacrylamide, manufactured by Harima Chemicals Co., Ltd.) was added.
As raw material pulp for the second pulp fiber layer, 100% used paper pulp was used. For this raw material pulp, a weakly acidic internal additive sizing agent (Harsize NES-680 emulsion rosin internal additive sizing agent manufactured by Harima Chemicals Co., Ltd.) (5 kg / t), a sulfuric acid band (21 kg / t), paper (4 kg / t) of a power agent (Harmide TA-238 cationic polyacrylamide manufactured by Harima Chemicals Co., Ltd.) was added.
As raw material pulp for the third pulp fiber layer, 100% waste paper pulp was used. In this raw material pulp, a weakly acidic internal additive sizing agent (Harsize NES-680 emulsion type rosin internal additive sizing agent manufactured by Harima Kasei Co., Ltd.) (4 kg / t), a sulfuric acid band (12 kg / t), paper (4 kg / t) of a power agent (Harmide TA-238 cationic polyacrylamide manufactured by Harima Chemicals Co., Ltd.) was added.
As a raw material pulp for the fourth pulp fiber layer, 100% used paper pulp was used. In this raw material pulp, a weakly acidic internal additive sizing agent (Harsize NES-680 emulsion type rosin internal additive sizing agent manufactured by Harima Kasei Co., Ltd.) (4 kg / t), a sulfuric acid band (12 kg / t), paper (2 kg / t) of a strengthening agent (Harmide TA-238 cationic polyacrylamide manufactured by Harima Chemicals) was blended.
As raw material pulp for the fifth pulp fiber layer, 100% waste paper pulp was used. For this raw material pulp, a weakly acidic internal sizing agent (Harsize NES-680 emulsion type rosin internal sizing agent manufactured by Harima Chemicals Co., Ltd.) (7 kg / t), sulfuric acid band (24 kg / t), paper A power agent (Harmide TA-238 Cationic Polyacrylamide, Harima Chemicals Co., Ltd.) was blended (3 kg / t).
A base paper having a five-layer structure including first to fifth pulp fiber layers was obtained in order from the surface side using each raw material pulp. The weight of the first pulp fiber layer is 25 g / m ² , the weight of the second pulp fiber layer is 38 g / m ² , the weight of the third pulp fiber layer is 47 g / m ² , and the weight of the fourth pulp fiber layer is Was 48 g / m ² , and the amount of the fifth pulp fiber layer was 47 g / m ² .
A starch layer was formed by spray coating between the first pulp fiber layer and the second pulp fiber layer and between the second pulp fiber layer and the third pulp fiber layer. In addition, J. of the obtained base paper. TAPPI paper pulp test method no. The paper surface pH measured by the method defined in 6-75 was 6.5.
(Preparation of coating solution)
(A) Cationic styrene resin (Polymaron 360 manufactured by Arakawa Chemical Co., Ltd.), (B) Cationic acrylamide resin (HG5304 manufactured by Seiko PMC), and (C) Vinyl alcohol polymer (Nippon Vinegar-Povar) JF-17 average polymerization degree 1,700, saponification degree 98.0-99.0%) was blended at 10: 9: 20 in terms of solid content to obtain a coating solution.
The coated liquid of Example 1 was obtained by applying the coating liquid on the surface of the base paper in a dry mass of 0.3 g / m ² and calendering.

[Examples 2 to 13, Comparative Example 1]
Except for the types of components (A) to (C) in the coating liquid, the amount (basis weight) of the surface layer (first pulp fiber layer), and the content of the rosin sizing agent on the surface layer as shown in Table 1. In the same manner as Example 1, coated papers of Examples 2 to 11 and Comparative Example 1 were obtained.
The surface layer weight (basis weight) was measured according to JIS-P8124 with respect to the surface layer peeled for each layer after obtaining coated paper.

[Comparative Example 2]
A coated paper of Comparative Example 2 was obtained in the same manner as in Example 1 except that the amount of sulfuric acid band added was reduced to a base paper having a paper surface pH of 7.0 in the raw material pulp of the surface layer.

In addition, each component in Table 1 is as follows.
Cationic styrenic resin: Polymeron 360 manufactured by Arakawa Chemical Industries
Anionic styrenic resin: manufactured by Arakawa Chemical Industries, Polymeron 351S
Cationic acrylamide resin: HG5304 manufactured by Seiko PMC
Anionic acrylamide resin: ST-5000 manufactured by Hoshimitsu PMC
-PVA1: Nippon Vinegar-Poval JF-17 Average polymerization degree 1,700, Saponification degree 98.0-99.0%
-PVA2: Nihon Azuma Bi-Poval JF-10 Average polymerization degree 1,000, Saponification degree 98.0-99.0%
-PVA3: Nippon Vinegar-Poval JC-25 average degree of polymerization 2,500, saponification degree 99% or more-PVA4: Nippon Vinegar-Poval JM-17 average degree of polymerization 1,700, saponification degree 95.5 ~ 97.5%

[Examples 14 to 21]
Example 1 except that the blending ratio of (A) cationic styrene resin, (B) cationic acrylamide resin and (C) vinyl alcohol polymer in the coating solution was as shown in Table 2. Similarly, coated papers of Examples 14 to 21 were obtained.

[Evaluation]
The following items were evaluated for each coated paper obtained. The evaluation results are shown in Tables 1 and 2.

[Surface strength]
The surface strength of the obtained coated paper was measured using JAPAN TAPPI No. Measured according to the description in 1.

[Water repellency]
On the surface of the obtained coated paper, an anionic water repellent (Ripax A-240 manufactured by Modern Science Industrial Co., Ltd.) was applied at a coating amount of 0.6 g / m ² to obtain a water-repellent paper. . The water repellency of the obtained water repellent paper was measured according to the method defined in JIS-P8137. Specifically, the obtained water-repellent paper is cut into a width of 200 mm and a length of 300 mm as a sample, and is fixed to a test piece mounting surface having an inclination of 45 degrees. One drop of distilled water was dropped from the burette, and the water repellency was determined by observing traces of flow. The water repellency was determined according to the following criteria. The high water repellency (water repellency) can be evaluated as the film forming property of the coated paper.
R ₀ : A continuous trace, showing a uniform width.
R ₂ : A continuous trace, showing a slightly narrower width than a water droplet.
R ₄ : Although it was a continuous trace, it was cut off several times and clearly showed a narrower width than a water droplet.
R ₆ : Half of the trace was wet.
R ₇ : A quarter or more of the trace was wet by a long water droplet.
R ₈ : Spherical droplets were scattered over 1/4 of the trace.
R ₉ : Spherical small water droplets were scattered everywhere.
R ₁₀ : Water droplets completely rolled down.

[Examples 22 to 27 and Comparative Example 3]
The coated papers of Examples 22 to 27 and Comparative Example 3 were obtained in the same manner as in Example 1 except that the coating amount of the coating liquid on the base paper surface was as shown in Table 3.

  About the coated paper of Example 1, Examples 22-27, and Comparative Example 3, the operability was evaluated based on the above water repellency and the following criteria. The evaluation results are shown in Table 3.

[Operability]
A: There is no operational problem.
○: Dryability is inferior, but there are no problems such as dirt.
Δ: Inferior in drying property and easily contaminated, but operable.
X: Problems occur in drying, and dirt is also generated.

  As shown in Table 1 and Table 2, each coated paper of the examples is excellent in surface strength. Moreover, since the water-repellent paper obtained from these coated papers is excellent in the film-forming property by a water-repellent agent, it turns out that the water repellency is high. Moreover, as Table 3 shows, it turns out that both water repellency and operativity can be improved by adjusting a coating amount.

  As described above, the coated paper of the present invention is suitable as a coated paper for self-water-repellent treatment, and specifically, can be suitably used as a liner for corrugated cardboard.

Claims (5)

It is a coated paper for self-repellent treatment in which a coating liquid is coated on the surface of the base paper,
The base paper is an acidic paper with a rosin sizing agent added internally,
The coating liquid, seen containing a cationic styrene resin, an acrylamide resin and the vinyl alcohol polymer,
The base paper has two or more pulp fiber layers,
A coated paper, wherein the first pulp fiber layer located on the surface contains a rosin-based sizing agent in a solid content concentration of 6 kg / t or more and 12 kg / t or less .   The coated paper according to claim 1, wherein the vinyl alcohol polymer has an average degree of polymerization of 1,200 to 2,200, and a saponification degree of 97% or more. The coated paper according to claim 1 or 2, wherein the basis weight of the first pulp fiber layer is 15 g / m ² or more and 35 g / m ² or less. Coating described above with the first pulp fiber layer, according to claim 1, further comprising a sediment Konaso between the second pulp fiber layer laminated on the inside of the first pulp fiber layer, according to claim 2 or claim 3 Craft paper. A water-repellent paper comprising the coated paper according to any one of claims 1 to 4 and a layer containing an anionic water-repellent agent laminated on the surface of the coated paper.