JP6462617B2 - Paper manufacturing method - Google Patents

Description

  The present invention relates to a paper manufacturing method, and more particularly to a paper manufacturing method having high wet strength and internal bond strength and suitable as a watercolor paper.

  Conventionally, various aptitudes are required for watercolor paper. For example, general suitability such as water absorbability, color developability, and color reproducibility, as well as the strength of the paper surface during paint application and wiping. In order to impart such characteristics, various proposals regarding watercolor paper have been made. For example, in Patent Document 1, water of water-based paint is quickly absorbed into the paper, the image line is not blurred, the color is uniform, and the paper is less likely to discolor or deteriorate in strength over time. A method for obtaining high-quality watercolor paper has been proposed. In Patent Document 2, the density of the pigment particles adsorbed on the cellulose fibers in the watercolor paper is increased by mixing the hemp fibers that have been mercerized without chemical tension into the chemical pulp, thereby achieving the depth effect of the pigment. There has been proposed a method of obtaining a watercolor painting paper whose color reproducibility can be measured on the paint paper.

  In Patent Document 3, a paper having good wet strength and alkali resistance is manufactured by adding guagam and polyamide epichlorohydrin resin to a pulp slurry in a weight ratio of 0.5: 1 to 1: 1. A method has been proposed. Further, Patent Document 4 proposes to provide a high wet strength paper excellent in wet strength and dimensional stability by mixing composite synthetic fibers with pulp fibers. Further, in Patent Document 5, a decorative board base paper that exhibits sufficient wet strength in a state where the shielding property and the filler OPAR are maintained by adding the wet paper strength agent in two steps, at the time of raw material preparation and immediately before papermaking, is disclosed. Manufacturing methods have been proposed. In patent document 6, it is a multilayer papermaking which consists of a paper layer which has a pulp as a main component and contains a surface layer and a back layer, Comprising: 70-100 mass% is LBKP among the pulp contained in the said surface layer. 40% to 70% by mass of the pulp contained in the entire multilayer paper is NBKP, the basis weight is 100 to 300 g / m2, and the wet paper strength enhancer is included. There has been proposed a multi-layer paper that is not easily torn even under an environment and has a surface smoothness that can satisfy printability such as a thermal transfer method, letterpress printing, and gravure printing.

  Furthermore, in Patent Document 7, hardwood kraft pulp is used as a main component, paper is made in the presence of a paper strength enhancer based on acrylamide, and the freeness of the pulp after disaggregation after disaggregating the base material for the lid is 350 to 500 cc. Yes, the weight average fiber length of the pulp after disaggregation is 0.5 to 1.0 mm, 90% by weight or more of the pulp after disaggregation is occupied by fibers having a fiber length of 1.5 mm or less, and the width direction of the base material for the lid material And a base material for a lid material characterized in that an average value of internal bonds in the flow direction is 200 mJ or more.

JP-A-10-018195 JP-A-10-168879 Japanese Patent Laid-Open No. 06-294094 JP-A-62-090400 JP 2011-219874 A Japanese Patent Laying-Open No. 2015-218422 JP 2010-149481 A

  Although various proposals have been made to improve wet paper strength and internal bond strength, watercolor paper that requires high wet paper strength and internal bond strength can provide a paper base material that can be satisfied by conventional technology alone. I was not able to. In addition, cotton paper may be selected as the main component of watercolor paper to improve paint suitability. However, when a large amount of cotton pulp is added, the wet paper strength tends to decrease. Insufficient resistance to rubbing.

  The present invention has been made in view of such problems, and the object of the present invention is to provide good abrasion resistance (hereinafter sometimes referred to as “wet friction strength”) and internal bond strength even in a wet state. An object of the present invention is to provide a method for producing a paper having a paper. Here, “abrasion resistance in a wet state” and “wet frictional strength” are evaluations to see the frictional strength of the paper surface in a wet state.

  Another object of the present invention is to provide a method for producing watercolor paper having good paintability in addition to the above characteristics.

  Further, other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the following description.

  The paper manufacturing method according to the present invention includes a step of making paper with a raw material adjusted by adding a polyamide epichlorohydrin-based epoxy resin, an anionic or amphoteric guagam, and a sulfuric acid band to a pulp slurry. And the addition ratio of the polyamide epichlorohydrin-based epoxy resin and the anionic or amphoteric guagam is in the range of 1: 1 to 1: 2 by weight, and the anionic or amphoteric guagam The addition ratio of the sulfuric acid band to is 0.1 to 0.5 times.

  According to such a configuration, it has excellent specific wet tensile strength, internal bond strength, and wet friction strength, and has sufficient strength even when it is repeatedly applied with a wet brush. Suitable paper can be produced.

  In a preferred embodiment of the present invention, the pulp slurry may contain 20% by mass or more of cotton linter pulp with respect to the total amount of pulp.

  According to such a configuration, the spread of the paint is improved, and a paper excellent in drawing suitability can be manufactured.

  In a preferred embodiment of the present invention, the freeness of the pulp in the pulp slurry may be 350 to 750 ml CSF.

  According to such a configuration, the texture of the paper surface can be easily adjusted, and paper having a paper surface more suitable for watercolor painting can be produced.

  In preferable embodiment of this invention, 1-4 mass% may be sufficient as the addition rate of the said polyamide epichlorohydrin type epoxy resin with respect to the absolute dry weight of a pulp.

  According to such a configuration, it is possible to produce a well-balanced paper that is excellent in wet friction strength and internal bond strength and that does not stain the inside of the papermaking system.

  In a preferred embodiment of the present invention, the watercolor paper has a specific wet tensile strength according to JIS P 8135: 1998 of 6.0 Nm / g or more, and JAPAN TAPPI No. The internal bond strength specified in 18-2 may be 125 mJ or more.

  According to such a configuration, sufficient wet friction strength and internal bond strength are ensured, and even when the paper surface is rubbed many times with a wet brush, it is suitable for watercolor paper without causing rough paper and falling off of paper dust. Paper can be manufactured.

  In a preferred embodiment of the present invention, the paper may be used as watercolor paper.

  According to such a configuration, it is possible to provide a watercolor paper having sufficient wet friction strength, internal bond strength, and good paint suitability.

  According to the present invention, it is possible to provide a paper having excellent wet friction strength and internal bond strength, and even when the paper surface is rubbed repeatedly with a wet brush when the paint is applied repeatedly, It is possible to provide paper that does not drop off paper dust.

  Further, according to a preferred embodiment of the present invention, in addition to the above-described features, it is possible to provide paper that has better paint suitability and is suitable as watercolor paper.

It is a graph (the 1) which shows the composition of the paper in an Example and a comparative example. It is a graph (the 2) which shows the composition of the paper in an Example and a comparative example. It is a graph which shows the physical property of the paper in an Example and a comparative example.

  The pulp used in the present invention is not particularly limited, and is represented by softwood bleached kraft pulp (NBKP), softwood bleached sulfite pulp (NBSP), hardwood bleached kraft pulp (LBKP), and hardwood bleached sulfite pulp (LBSP). Wood bleached chemical pulp can be used. In addition, as required, mechanical pulp such as GP (crushed wood pulp), TMP (thermomechanical pulp), BCTMP (bleached chemithermomechanical pulp), waste paper pulp, and other than wood pulp, cocoon, cocoon, husk, hemp Non-wood pulp such as bagasse, kenaf, bamboo, and cotton linter, synthetic pulp, synthetic fiber, and the like can be appropriately selected and used. Among these, it is preferable to contain cotton linter pulp from the viewpoint of improving drawing suitability.

  In the present invention, by including cotton linter pulp in the pulp slurry, it is possible to obtain a paper suitable as a watercolor paper having excellent drawing suitability. Since cotton linter pulp has a relatively long fiber length compared to wood pulp or the like, it is possible to appropriately improve the spread of the paint on the paper surface by capillary action. For this reason, paper blended with cotton linter pulp has excellent drawing suitability for water-based paint (hereinafter sometimes referred to as “paint suitability”), and is more suitable as a watercolor paper.

  In the present invention, the blending amount of the cotton linter pulp is not particularly limited, but is preferably 20% by mass or more, more preferably 50% by mass or more, and more preferably 70% by mass or more based on the total pulp. Further preferred. Basically, as the blending amount of cotton linter pulp increases, the suitability of paper paint improves.

  In addition, cotton linter pulp has a problem that it is difficult to obtain wet friction strength compared to other wood pulp (for example, LBKP), and even when used together with LBKP, it becomes wet as the blending amount of cotton linter pulp increases. The friction strength tends to decrease. That is, the provision of proper paint and the wet friction strength by blending cotton linter pulp are in a trade-off relationship, and it is difficult to achieve both. However, according to the present invention, a paper having a high wet friction strength and an internal bond strength even when cotton linter pulp is used by combining an epoxy resin, an anionic or amphoteric guar gum, and a sulfuric acid band. Thus, it is possible to achieve both paint suitability and wet friction strength. In addition, since the paper has high wet friction strength, internal bond strength, and paint suitability, the paper according to the present invention is fluffy even if it is rubbed with a wet brush many times when paint is overcoated. It is difficult to use as watercolor paper.

  Although the freeness of the pulp used in the present invention is not particularly limited, it is 350 Canadian freeness (JIS P 8121: 1995 “Pulp Freeness Test Method”) for each pulp. It is preferably ˜750 ml CSF, more preferably 400 to 700 ml. By setting the freeness within this range, it becomes easy to prepare the texture, and it becomes easy to obtain a paper surface suitable for a watercolor painting having a suitable texture and a proper texture. When the freeness of the pulp is less than 400 ml CSF, the water absorbability becomes poor, and there is a possibility that the paint quality cannot be satisfied. Conversely, if it exceeds 750 ml CSF, the formation may be deteriorated.

  The polyamide epichlorohydrin-based epoxy resin used in the present invention can be produced, for example, by condensing a saturated dibasic acid and a polyalkylene polyamine to form a polyamide, and then reacting epichlorohydrin. . Such epoxy resins are water-soluble, cationic, and thermosetting, and are agents that impart wet and dry strength to paper in a wide pH range from weakly acidic to alkaline.

  The addition rate of the polyamide epichlorohydrin type epoxy resin used in the present invention is preferably 1 to 4% by mass based on the dry weight of the pulp. When the addition rate is less than 1% by mass, the effect of the epoxy resin cannot be sufficiently obtained, and the wet friction strength and the internal bond strength may not be sufficiently improved. On the other hand, if the addition rate exceeds 4% by mass, the improvement in wet friction strength and internal bond strength will reach a peak, and there is a concern about contamination in the papermaking system due to excessive addition of polyamide epichlorohydrin epoxy resin. This is also economically disadvantageous.

  Gua gum used in the present invention is a kind of polysaccharide, and the main component is mannogalactan. It is obtained from the endosperm of Guar (cluster bean) tree seeds cultivated in India and the United States, and is used as a beater additive, wet end additive, surface paper strengthening agent, etc. to enhance strength properties. As the guagam used in the present invention, anionic or amphoteric guagam is effective. This is to improve the paper strength by suitably bonding with a cationic polyamide epichlorohydrin type epoxy resin.

  In the present invention, polyamide epichlorohydrin type epoxy resin and gua gum are added to the pulp slurry in a range of 1: 1 to 1: 2 by weight ratio. If the addition rate of guagam is less than this range, the effect of improving wet friction strength is insufficient. On the contrary, if the addition rate of guagam exceeds this range, the potential of the pulp slurry is biased to an excessive negative value, leading to deterioration of the fixing of raw material chemicals, resulting in a decrease in wet tensile strength and internal bond strength.

  In this invention, the addition amount of a sulfuric acid band shall be 0.1 to 0.5 time with respect to the gua gum in a pulp slurry. In addition, the addition amount of a sulfuric acid band here is the value of aluminum sulfate 16 hydrate conversion. By adding the sulfuric acid band to the gua gum within the above range, the wet friction strength and the internal bond strength of the paper are greatly improved. If the amount of sulfate band added to guagam is less than 0.1 times, the effect of improving wet friction strength and internal bond strength by the sulfate band cannot be sufficiently obtained because the amount of sulfate band added is insufficient. On the other hand, if the amount of sulfate band added to guagam is larger than 0.5 times, the wet friction strength and the internal bond strength will reach the peak, and the pulp slurry will become cationic, causing soiling in the papermaking system. This is a concern and is also economically disadvantageous.

  It is considered that the wet friction strength and the internal bond strength are improved by adding the sulfuric acid band due to the following mechanism of action. Assuming the usage situation when used as a watercolor paper, the strength decreases due to moisture penetrating into the paper when drawing with paint, and further, it is rubbed with a brush etc. Roughness and falling off of paper dust occur. Therefore, it is considered that not only wet tensile strength but also internal bond strength is related to the strength of wet friction strength. In the present invention, the wet friction strength and the internal bond strength are greatly improved by adding the sulfuric acid band, because the sulfite band neutralizes with a cation the pulp slurry whose potential is inclined negatively by guagum. This is thought to be due to an improvement in the generalization of papermaking chemicals.

  The order of addition of polyamide epichlorohydrin epoxy resin, anionic or amphoteric guar gum, and sulfuric acid band is not particularly limited. For example, after the pulp is dispersed in water, the polyamide An order may be considered in which a predetermined amount of epichlorohydrin epoxy resin and anionic or amphoteric guar gum are added and dispersed, and then a sulfuric acid band is added.

  In the present invention, the pulp slurry can contain various papermaking materials such as a filler, a sizing agent, a paper strength agent, and a yield improver, as long as the effects of the present invention are not impaired. As the filler, one or more known fillers such as hydrated silicic acid, white carbon, talc, kaolin, clay, calcium carbonate, titanium oxide, aluminosilicate, calcined clay, barium sulfate and synthetic resin filler can be used. Of these, calcium carbonate is effective in improving the storage stability of paper.

  When a sizing agent is used in the present invention, those exhibiting good sizing properties by internal addition are preferable. For example, paraffin wax sizing agent, microcrystalline wax sizing agent, carnauba (carnauba wax) sizing agent, alkyl One or more ketene dimer wax sizing agents, rosin sizing agents, alkenyl succinic anhydride sizing agents, and the like can be used. Examples of paper strength agents include starch, cationized starch, other modified starch, polyacrylamide resin, urea formalin resin, melamine formalin resin, vegetable gum, polyvinyl alcohol, modified polyvinyl alcohol, rubber latex, polyethylene oxide, polyamide resin, etc. One or more can be used. Among these, it is preferable to use cationized starch and polyacrylamide which are highly effective in improving the surface strength and interlayer strength among these.

  Moreover, in this invention, various adjuvants can also be apply | coated to the surface of paper with a size press as needed. For example, a paper strength agent such as gelatin, starch, polyvinyl alcohol, or polyacrylamide can be applied with a size press in order to improve the fixability and surface strength of the paint. In addition, a surface sizing agent such as a styrene acrylic resin or an alkyl ketene dimer may be applied for the purpose of improving sizing properties.

  In the present invention, the paper making method is not particularly limited, and a conventionally known paper machine such as a circular paper machine, a short paper machine, a long paper machine, or a combination paper machine of these paper machines is used. It can be made in a single layer or by combining. In the case of papermaking, a paper strength agent such as interlayer starch may be sprayed to prevent delamination of each layer of the papermaking.

  As described above, the paper according to the present invention is excellent in wet friction strength and internal bond strength. As for the wet friction strength, the specific wet tensile strength measured in accordance with JIS P 8135: 1998 (paper and paperboard-wet tensile strength test method) is 6.0 Nm / g or more, and the internal bond strength is JAPAN TAPPI. No. If the internal bond strength measured by the method specified in 18-2 (Paper and paperboard-Internal bond strength test method-Part 2: Internal bond tester method) is 125 mJ or more, the object of the present invention is satisfied. The paper is free from rough paper and falling off of paper dust.

  Next, although an example and a comparative example are given and the present invention is explained more concretely, the present invention is not limited to these examples. Further, “parts” and “%” in the examples respectively represent parts by mass or mass% in terms of solid content unless otherwise specified. Moreover, about a sulfuric acid band, the solid content part as aluminum sulfate 16 hydrate is shown.

Example 1
100 parts of cotton linter pulp (freeness 574 ml CSF) are dispersed in water to form a pulp slurry, and polyamide epichlorohydrin-based epoxy resin (trade name: Polyfix 259, Showa Denko KK) 1.0 part is added to the pulp slurry. , 1.0 part of anionic guagam (trade name: Mayproid 840 / D0, manufactured by Danisco-Zandam-BV) and 0.5 part of sulfuric acid band (manufactured by Techno Hokuetsu) were added to obtain a paper stock. Paper was used to make paper with an experimental hand-making device (Juken type square paper-making device) to obtain a paper having a basis weight of 95 g / m2.

(Example 2)
A paper was obtained in the same manner as in Example 1 except that the addition rate of anionic guagam was 2.0 parts.

(Example 3)
A paper was obtained in the same manner as in Example 2 except that the addition rate of the sulfuric acid band was 0.2 part.

(Example 4)
A paper was obtained in the same manner as in Example 2 except that the addition rate of the sulfuric acid band was 1.0 part.

(Example 5)
A paper was obtained in the same manner as in Example 2 except that 2.0 parts of anionic guagam were changed to 2.0 parts of amphoteric guagam (trade name: Mayproid K, manufactured by Danisco-Zaandam-BV).

(Example 6)
A paper was obtained in the same manner as in Example 4 except that the addition rate of the polyamide epichlorohydrin epoxy resin was changed to 2.0 parts.

(Example 7)
A paper was obtained in the same manner as in Example 1 except that the pulp to be used was changed to 50 parts of cotton linter pulp (freeness 574 ml CSF) and 50 parts of NBSP (freeness 495 ml CSF).

(Example 8)
A paper was obtained in the same manner as in Example 1 except that the pulp to be used was changed to 50 parts of cotton linter pulp (freeness 574 ml CSF) and 50 parts of LBKP (freeness 501 ml CSF).

Example 9
A paper was obtained in the same manner as in Example 1 except that the pulp to be used was changed to 100 parts of NBSP (freeness 495 ml CSF).

(Example 10)
A paper was obtained in the same manner as in Example 1 except that the pulp used was changed to 100 parts of LBKP (freeness 501 ml CSF).

(Reference Example 1)
A paper was obtained in the same manner as in Example 2 except that the addition rate of the sulfuric acid band was changed to 2.0 parts.

(Comparative Example 1)
A paper was obtained in the same manner as in Example 1 except that the sulfuric acid band was changed to no addition.

(Comparative Example 2)
A paper was obtained in the same manner as in Example 2 except that the sulfuric acid band was changed to no addition.

(Comparative Example 3)
A paper was obtained in the same manner as in Example 1 except that the addition ratio of the anionic guagam was changed to 4.0 parts.

(Comparative Example 4)
A paper was obtained in the same manner as in Example 1 except that 1.0 part of anionic guagam was changed to 1.0 part of nonionic guagam (trade name: MAYPROID 5306, manufactured by Danisco-Zaandam-BV).

(Comparative Example 5)
A paper was obtained in the same manner as in Example 1 except that 1.0 part of anionic guagam was changed to 1.0 part of cationic guagam (trade name: Mapbond 111, manufactured by Danisco-Zadam-BV).

(Comparative Example 6)
A paper was obtained in the same manner as in Example 1 except that the addition ratio of the anionic guagam was changed to 0.5 part.

(Comparative Example 7)
A paper was obtained in the same manner as in Example 9 except that the sulfuric acid band was changed to no addition.

  1 and 2 show the outline of the stock composition in each example, reference example and comparative example, and FIG. 3 shows the evaluation results of the obtained paper. The evaluation was performed by the following methods.

<Specific wet tensile strength>
In accordance with JIS P 8135: 1998 (paper and paperboard—wet tensile strength test method), the wet tensile strength is measured in each of the direction along the side of the paper (longitudinal direction) and the direction perpendicular to the side (transverse direction). Then, the value obtained by dividing the average value by the value of rice tsubo (g / m @ 2) was taken as the value of specific wet tensile strength.

<Internal bond strength (internal bond)>
JAPAN TAPPI No. It was measured by the method specified in 18-2 (Paper and paperboard-Internal bond strength test method-Part 2: Internal bond tester method).

<Wet friction strength>
One side of the paper obtained in the examples and comparative examples, using a Gakushin type friction fastness tester (JIS P 8136 compliant tester industry) adjusted with a weight so that the weight of the friction part is 300 g. Secure to the testing machine so that becomes the test surface. 100% cotton bias tape (trade name: CP25 Hi-cotton CP34 pure cotton color 290, manufactured by Captain Co., Ltd.) is immersed in the friction part for 1 minute or longer in distilled water adjusted to 23 ° C., and then the bias tape is squeezed. Do not install. After reciprocating 5 times while the friction part is in contact with the test surface of the paper, the paper and the friction part bias tape are removed from the testing machine. After sufficiently removing the removed paper and the friction part bias tape, both the test surface of the paper and the rubbing part of the bias tape were visually checked for roughness of the paper test surface and paper powder falling off. Rated by stage.
A: Roughness of the paper surface and falling off of paper dust are not recognized. Pass.
○: Roughness of the paper surface and falling off of paper dust are slightly observed, but there is no practical problem. Pass.
(Triangle | delta): Roughness of paper surface and drop-off | omission of paper dust are recognized, and there is a problem in practical use. failure.
X: Roughness of the paper surface and falling off of paper dust are remarkably problematic. failure.

<Applicability of paint>
In the case of watercolor paper, it is important as a function that the applied paint spreads uniformly. In this evaluation of paint suitability, the extent of paint spread was visually confirmed. Specifically, it is fixed to a wooden panel so that one side of the paper becomes the test surface, and distilled water adjusted to 23 ° C. is uniformly applied with a flat brush until the test surface becomes glossy. Immediately after the applied water is semi-dried by absorption and evaporation on paper (no gloss due to water), immediately after the height of 1 cm from the paper surface, watercolor paint (trade name: Cobalt Blue, Holbein Industry Co., Ltd.) The aqueous solution of the paint diluted 10-fold with distilled water was dropped with a 1 ml syringe and allowed to dry naturally, and the extent of the paint was visually confirmed and evaluated in the following four stages.
A: Radially and uniformly spread from the end surface of the dropping liquid by 2 cm or more. Pass.
◯: Spread approximately 1.5 cm to 2 cm radially from the end surface of the dropping liquid. Pass.
Δ: Although spread 1 cm or more radially from the end surface of the dropping liquid, the spreading method is uneven, and there is a problem in practical use. failure.
X: It spreads less than 1 cm, and there is a problem in practical use. failure.

  As is clear from FIG. 3, the paper obtained in each example of the present invention has a specific wet tensile strength (longitudinal) of 6.0 Nm / g or more and an internal bond strength (internal bond) of 125 mJ or more. The wet friction strength was also practically acceptable. Moreover, the paper of Examples 1-8 which mix | blended cotton linter pulp was the paper suitable also as a watercolor painting paper excellent also in paints suitability.

  On the other hand, the papers of Comparative Examples 1, 2, and 7 to which no sulfuric acid band was added had paint suitability, but were not suitable for practical use in terms of wet friction strength, internal bond strength, and wet tensile strength. there were. This is considered to be because the effects of various papermaking chemicals were not sufficiently obtained because the sulfuric acid band was not added.

  Further, as is clear from the results of Example 4 and Reference Example 1, the wet friction strength, the internal bond strength, and the wet tensile strength can be increased even when a sulfuric acid band having an amount larger than 0.5 times the amount of gua gum is added. In addition to the fact that the improvement is not observed, it is apparent that the inside of the papermaking system is unfavorable in terms of both operability and economy, because it becomes a factor of soiling due to the tendency to be cationic.

  From the results of Examples 1 and 2 and Comparative Examples 3 and 6, the addition ratio of the polyamide epichlorohydrin type epoxy resin and guagam is preferably in the range of 1: 1 to 1: 2 by weight ratio. . As in Comparative Example 6, when the addition rate of guagam is less than 1 by weight with respect to the addition rate of the polyamide epichlorohydrin epoxy resin, the wet friction strength, internal bond strength, and wet tensile strength are all poor. It becomes. Conversely, when the addition rate of guagam exceeds 2 by weight with respect to the addition rate of the polyamide epichlorohydrin epoxy resin as in Comparative Example 3, the potential of the pulp slurry is excessively negative and the raw material chemical is fixed. Deteriorated and led to a decrease in internal bond strength.

  Further, as is clear from the results of Examples 2 and 5 and Comparative Examples 4 and 5, anionic or amphoteric guagam is required for the combined use with the polyamide epichlorohydrin epoxy resin. This is because the polyamide epichlorohydrin epoxy resin which is cationic and the anionic or amphoteric guagam are suitably bonded to improve paper strength.

  According to the present invention, paper having good wet friction strength and internal bond strength can be produced, and such paper is also suitable as watercolor paper.

Claims (6)

A process of making paper with a raw material adjusted by adding a polyamide epichlorohydrin-based epoxy resin, an anionic or amphoteric guagam, and a sulfuric acid band to a pulp slurry;
The addition ratio of the polyamide epichlorohydrin-based epoxy resin and the anionic or amphoteric guagam is in the range of 1: 1 to 1: 2 by weight ratio,
The method for producing paper, wherein the addition ratio of the sulfuric acid band to the anionic or amphoteric guagam is 0.1 to 0.5 times.   The paper manufacturing method according to claim 1, wherein the pulp slurry contains 20% by mass or more of cotton linter pulp with respect to the total amount of pulp.   The paper manufacturing method according to claim 1 or 2, wherein the freeness of the pulp in the pulp slurry is 350 to 750 ml CSF.   The method for producing paper according to any one of claims 1 to 3, wherein the addition rate of the polyamide epichlorohydrin-based epoxy resin is 1 to 4% by mass with respect to the absolute dry weight of the pulp. .   The specific wet tensile strength according to JIS P 8135: 1998 of the paper is 6.0 Nm / g or more, and JAPAN TAPPI No. The method for producing paper according to any one of claims 1 to 4, wherein the internal bond strength defined in 18-2 is 125 mJ or more.   6. The paper manufacturing method according to claim 1, wherein the paper is watercolor paper.

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