JP6052069B2 - Transpiration paper and method for producing the same - Google Patents

Description

The present invention is a paper used as a paper humidifier that humidifies the surrounding space by spontaneously evaporating water sucked up by capillary action, and is self-supporting in a state of high water absorption, offset printing suitability, and the whole paper is moist. It relates to transpiration paper.

In recent years, a humidifier used in a room that tends to be dried by heating requires a certain installation space and needs to secure a power source. However, paper humidifiers that do not use electricity are recognized and attracting attention because of the lack of power supply and safety due to the effects of the earthquake. A paper humidifier is a mechanism that humidifies the interior of a paper base by absorbing moisture and increasing the wet paper surface area to promote water evaporation. This is effective because it greatly exceeds the amount of natural evaporation. Since it is a natural humidifier that does not use electricity, it is silent and does not charge electricity, and it does not forcibly spray water vapor. Widely used. More recently, flowers have been printed to make it look like a bouquet, making it visually appealing, and being used for ornamental purposes to color rooms and offices.

There are various types of natural humidifiers that do not use electric power. Among them, the technology to make paper substrate self-supporting when flooded is binder fiber (heat welding) with synthetic fiber (polyester fiber etc.) in paper substrate. There is a technology that can be solidified and fixed with polyester fiber) to make it self-supporting, but it is difficult to make paper self-supporting when it is submerged with paper based on wood pulp, non-wood pulp, or blends. Met. Therefore, it is a suspension type that avoids self-supporting, or a method of self-supporting as a three-dimensional structure by folding or bending (Patent Documents 1, 2, 3, 4, 5) or a self-supporting auxiliary tool (suspended on a frame) A method (Patent Document 5) and the like are disclosed.

In general, products that are sold as paper humidifiers are made of filter paper having high water absorption, especially thick filter paper. However, the filter paper can absorb water, but if the entire paper is moistened, hydrogen bonds between cellulose fibers will loosen, making the paper soft and unable to stand on its own, which is not suitable for long-term use. It was. Also, since the surface strength is weak, efficient printing, especially offset printing, is not possible, and it is limited to those that are colored on paper without silk printing or printing that is unsuitable for mass production and costly. Is the current situation.

JP 2004-250839 A JP 2007-107768 A Japanese Patent Laid-Open No. 4880012 JP 2011-62816 A JP 2013-44518 A

An object of the present invention is to provide a transpiration paper that can absorb water sufficiently as a paper humidifier, can stand by itself without the presence of an auxiliary tool, can be used for a long time, and is printable.

The inventors have intensively studied the necessary water absorption capacity as a paper humidifier and the characteristics necessary for long-term independence in the water-absorbed state, and completed the present invention.
That is, the present invention includes the following inventions.
(1) A transpiration that is based on wood pulp or non-wood pulp, has a Krem water absorption of 40 mm or more as defined in JIS P 8141, and a Wet Taber stiffness of 3.0 mN · m or more, and is self-supporting in a state where the whole has absorbed water. paper.
(2) The transpiration paper according to (1), which contains a wet paper strength agent.
(3) The transpiration paper according to (1) 1 or (2), wherein a wet paper strength agent and polyacrylamide are used in combination.
(4) The transpiration paper described in any one of (1) to (3), wherein the polyacrylamide is anionic.
(5) A surface paper strength agent is coated on the paper surface, and JAPAN TAPPI No. The transpiration paper according to any one of (1) to (4), wherein the surface strength measured by the method 1 is 10 A or more.
(6) A surface coating solution containing a surface paper strength agent and a surfactant is applied to a paper base material having a sizing degree measured by the JISP8122 sizing human sizing test method of 10 seconds or less (1) to A method for producing the transpiration paper described in (5).

As a paper humidifier, the Krem absorbency specified in JIS P 8141 is set to 40 mm or more in order to have a sufficient transpiration effect, and the wet taber stiffness is set to 3.0 mN · By setting it to m, it is possible to stand on its own with a paper base material alone. Furthermore, by using a wet paper strength agent and polyacrylamide in combination, it becomes possible to stand up for a longer time. By adjusting the degree of sizing of the paper substrate and applying a surface paper strength agent and a surfactant, it is effective in imparting printability while maintaining water absorption and self-supporting properties.

Specific method of inundation independence test Specific method for evaluating water transpiration

In the present invention, in order to obtain a sufficient transpiration effect as a paper humidifier, a water absorption of Klem water absorption of 40 mm or more, preferably 50 mm or more is required. If the water absorption of Klem is less than 40 mm, water does not penetrate into the top of the paper when the transpiration paper is placed on the water, so that the area of the wet part is too small to exhibit a sufficient transpiration effect. . If the water absorption is 50 mm or more, even if the transpiration paper has a practical size of about 20 cm in height, the water reaches almost the end, so that the function as the transpiration paper can be fully exhibited.

Moreover, in this invention, in order to become independent without an auxiliary tool in the water-absorbed state, the wet Taber rigidity needs to be 3.0 mN · m or more. Wet Taber stiffness here is measured according to JIS P 8125 Taber stiffness test method after a 38 mm × 70 mm Taber stiffness sample is immersed in water for 30 seconds and excess water is absorbed by filter paper. It is the Taber stiffness. The transpiration paper is set up in low stretched water, but if the Wet Taber stiffness is less than 3.0 mN · m, the transpiration paper of about 20 cm, which is a practical size, will absorb the water. It is because it falls down by the weight of and does not become independent. That is, in order to function as a transpiration paper, the Taber stiffness in a state of absorbing water is required to be 3.0 mN · m or more.

The transpiration paper in the present invention is produced using wood pulp or non-wood pulp.
Examples of the fiber material that can be used in the present invention include wood pulp, non-wood pulp, and synthetic fiber. As the wood pulp, wood pulp generally used for papermaking can be used. For example, kraft pulp (KP), sulfite pulp (SP), soda pulp (AP), etc., chemical pulp, semi-chemical pulp (SCP), semi-chemical pulp such as Chemi-Grandwood pulp (CGP), ground pulp (GP), thermomechanical pulp (TMP, BCTMP), refiner Grandwood pulp (RGP) and other mechanical pulp, used paper pulp, etc. can be used .

Non-wood pulp is a fiber collected from skin, stem, leaf, leaf sheath, for example, cotton linter, straw, esparto, rags (cotton, linen, cannabis, ramie, etc.), Manila hemp such as abaca, bamboo / gabas, There are pulps obtained from ganpi, mitsumata, kozo and mulberry, but not limited to these, various raw materials can be used.
Among non-wood pulps, cotton linter pulp is the most water-absorbing and preferred, but it has an effect on stiffness, so 40 to 60% is preferred, and a Canadian standard freeness of about 400 to 600 cc is desirable.

Synthetic fibers are often excellent in water resistance, processability, strength, etc., but generally tend to have low rigidity. Examples of synthetic fibers that can be used in the present invention include polyester fiber, polypropylene fiber, acrylic fiber, nylon fiber, aramid fiber, polyethylene fiber, and the like, but any fiber is not limited thereto.

The most common paper raw materials currently on the market are often composed only of softwood bleached kraft pulp (NBKP) and hardwood bleached kraft pulp (LBKP). In that case, as a preferable blending ratio of the transpiration paper of the present invention, NBKP: 20-50%, LBKP: 80-50%. When a large amount of NBKP is added, it will work predominately when placed in water, but it will be difficult to form a flat texture when paper is made. Because there is a possibility of giving. On the other hand, if the blending of NBKP having a long fiber length is low, the stiffness of the paper itself becomes weak, and in particular, it becomes difficult to self-support when sucking water, so the blending ratio described above is preferable.

The pulp used for the paper base material of the present invention can be beaten and used by a known method. There are no particular limitations on the beater, and various beaters such as a beater, Jordan, a deluxe refiner (DF), and a double disc refiner (DDR) are used. In the case of blending two raw pulps, beating may be beaten and blended alone, or may be beaten after mixing. The degree of beating is preferably 300 to 600 cc in Canadian Standard Freeness (CSF). The reason is that if the beating is advanced to a certain extent, the inter-fiber bond advances and the rigidity is increased. However, if the beating is advanced too much, NBKP, which is a long fiber, becomes shorter and the rigidity becomes weaker, and the water absorption becomes worse. Therefore, 300 cc or more, more preferably about 400 to 600 cc is preferable.

As the paper machine for making the transpiration paper of the present invention, it is a conventional wet part paper machine such as a long net, circular net, inclined wire, etc. A drying method can be adopted. In making the transpiration paper of the present invention, one layer or multiple layers may be used, but one layer is preferable. In the case of multiple layers, there is a risk of peeling between layers due to long-term water immersion. Further, adhesion between layers may affect water absorption.

Moreover, after making the transpiration paper of the present invention, when actually used, it is preferable to design the machine so that the machine traveling direction (Machine Direction = MD direction) is the same as the paper rising direction. The reason for this is that when making paper, the pulp slurry adheres to the surface of the moving wire and a fiber sheet is formed. This is because the strength in the (MD direction), particularly the stiffness which is important for transpiration paper, tends to be strong. This tendency is particularly noticeable in the case of a circular paper machine, but the rigidity in the MD direction is generally larger than that in the direction perpendicular to the machine (CD direction) even in a long paper machine. Further, when it is desired to increase the rigidity in the MD direction, it is possible to increase the rigidity in the MD direction by taking measures such as increasing the J / W ratio of the long net paper machine and increasing the tension in each part of the machine.

The raw material of the transpiration paper of the present invention can contain a wet paper strength enhancer generally used in the paper industry. As the wet paper strength enhancer, polyamide epichlorohydrin resin, urea formaldehyde resin, melamine formaldehyde resin, polyamide polyamine epichlorohydrin (PAE), polyvinylamine (PVAm) and the like can be used.

It is preferable to contain the said wet paper strength enhancer in 0.3-5 mass% with respect to pulp in solid conversion. If it is less than 1% by mass, a sufficient effect is not exhibited, and even if it is contained in an amount exceeding 5% by mass, the effect is not limited, it affects water absorption, and there is a risk of causing stains during the process of papermaking. Therefore, 0.5 to 2% by mass is particularly preferable.

Also, the combined use of wet paper strength enhancer and polyacrylamide (PAM), which is used as one of dry paper strength enhancers in the paper industry, increases rigidity and makes it easier to stand up for a long time. It is preferable to contain. In addition, PAM has amphoteric, cationic, anionic, etc., all of which are effective, but by using anionic, the binding with the wet paper strength enhancer that is cationic becomes stronger, so that a longer time is required. Paper that can stand on its own. Polyacrylamide (PAM) is in the range of 0.2 to 3% by mass, and preferably in the range of 0.2 to 2% by mass in terms of solids.

In the present invention, it is preferable to contain an internal sizing agent in order to efficiently produce a printable transpiration paper. This is not required unless printing on the transpiration paper or writing on the surface, but if it has printability, the surface paper is used to increase the strength of the surface in order to increase the surface strength. This is because it is necessary to apply a force agent, but at that time, the liquid soaks into the substrate too much, and the drying efficiency is lowered, which greatly affects the operability.

However, since the sizing agent has an effect of suppressing water permeation on the paper, there is a possibility of affecting the water absorption when used as a transpiration paper, so the sizing degree needs to be adjusted. In the present invention, the sizing degree after papermaking is adjusted to be 10 seconds or less according to the JIS P8122 Steecht sizing test method. If the Steecht size exceeds 10 seconds, it cannot be used as a transpiration paper, and the surface treatment liquid will not easily penetrate into the paper even during the paper manufacturing process. It becomes possible.

As the internal sizing agent that can be used, rosin-based sizing agents are the most common. Maleic anhydride or fumaric acid is thermally added to rosin to form maleated rosin or fumarated rosin, and alkali is added to form a solution. There are reinforced rosin sizing agents and emulsion sizing agents which are dispersed in water using an emulsifier. The rosin sizing agent is used in combination with aluminum sulfate as a fixing agent and a hydrophobizing agent for pulp. The synthetic sizing agent is a neutral sizing agent obtained by converting C ₃ and C ₄ fractions obtained by pyrolyzing the raw material naphtha into a ₃ to 4 oligomer and then reacting with maleic anhydride to saponify the alkali. They can be classified into alkyl ketene dimers, alkenyl succinic anhydrides, etc., and any of these can be used in the present invention.

In the present invention, it is preferable to apply a liquid containing two types of chemicals, a surface paper strength agent and a surfactant, to a paper base material containing an internally added sizing agent and adjusted to have a sizing degree of 10 seconds or less. . The reason for this is that the present inventors have found that the incorporation of a surfactant is effective in order to facilitate the application of an aqueous liquid to paper containing an internal sizing agent. This is because it has been found that the surface strength of paper after coating can be increased by simultaneously blending the surface paper strength agent.

Examples of the surface paper strength agent that can be used in the present invention include raw starch, oxidized starch, esterified starch, cationized starch, and acetylated tapioca starch as raw materials. It is preferable to include starch such as starch, knitted starch such as aldehyded starch and hydroxyethylated starch. Cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, polyacrylamide, polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, modified alcohols such as acetoacetylated polyvinyl alcohol, styrene-butadiene copolymer, polyvinyl acetate, vinyl chloride-vinyl acetate Copolymers, polyvinyl chloride, polyvinylidene chloride, polyacrylic acid esters and the like can also be used in combination. In addition, surface sizing agents such as styrene sizing agents, olefin sizing agents, acrylate sizing agents, styrene-acrylic sizing agents, and cationic sizing agents can be used in combination, but polyacrylamide is preferred.

In the present invention, as the surfactant used together with the surface paper strength agent, polyoxyethylene nonyl ether, polyoxyethylene lauryl ether, alkyl naphthalene sulfonic acid soda, fatty acid polyethylene glycol ester, lauryl sulfate polyoxyethylene soda, polyethylene glycol Anions such as oxynonyl phenyl ether, nonions, cations, amphoteric surfactants, and the like can be used in the present invention.

In the present invention, as for the coating apparatus for the coating liquid, bevel type and vent type blade coaters such as trailing, flexible, roll application, fountain application, short dwell, and air knife generally used in the industry. Coater, Bar Coater, Rod Blade Coater, Champ Flex Coater, Gate Roll Coater, Curtain Coater, Slot Die Coater, Gravure Coater, Spray Coater, Known Size Press Equipment, For example, 2 Roll Type, 3 Roll Type, Gate Roll Type, A film transfer type or the like can be used. Of course, these apparatuses may be an on-machine type or an off-machine type. The film transfer type is a system in which a coating film in a wet state is formed on an applicator roll, and the coating film is transferred to the surface of the base paper. Examples thereof include a transfer roll coater and a rod metering size press coater.
After applying the surface treatment coating solution to at least one surface of the paper base material with these coating apparatuses at 0.5 to 5.0 g / m ² , it can be dried with a dryer and finished. However, in order to improve printability, a machine calendar, It is preferable to perform processing by a calendar device such as a soft calendar or a shoe calendar.

Additives such as fillers, dyes, slime control agents, pitch control agents, antifoaming agents, etc. can be added as needed, as long as they do not affect water absorption and stiffness. It is also possible to add chemicals such as fragrances, deodorants, insect repellents, and fungicides.

Although not limited to this, the basis weight is preferably 150 to 600 g / m ² . When the basis weight is low, the rigidity is difficult to be produced and it is difficult to stand by itself. When it is thick, it is difficult to print, which is not economical.

According to the present invention, an internal sizing agent is added to a pulp slurry, a wet paper strength agent and an anionic polyacrylamide are added, and papermaking is performed to obtain a transpiration paper that retains water absorption and can stand on its own. In addition, by coating the both sides of the paper with a surfactant having wettability and permeability together with the surface paper strength agent, while having water absorbency and offset printing suitability, the entire paper is in a wet state. A paper that can stand on its own for a stable time is obtained.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these.
In addition, the part and% used here are a mass part and the mass%. Example 4 is a reference example.

Example 1
The pulp slurry of NBKP 30% and LBKP 70% was mixed and beaten with a double disc refiner (DDR) so that the Canadian standard freeness was 500 cc. Subsequently, 0.1 part of aluminum sulfate is added to 100 parts of pulp solid, 0.6 parts of wet paper strength enhancer (manufactured by Starlight PMC, WS4024), anionic polyacrylamide ( Arakawa Chemical Polystron 117) 0.3 parts in solid form was added to prepare a paper stock. Using this stock, a sheet having a basis weight of about 420 g / m ² was produced with a long paper machine. Sampling was performed from the sheet, and the following tests were performed. The results are shown in Table 1.

Test method
(1) Rice tsubo The rice tsubo was measured according to JIS P 8124.
(2) Thickness and density The thickness and density were measured according to JIS P 8118.
(3) Taber stiffness / WET Taber stiffness The Taber stiffness was measured according to the JIS P 8125 Taber stiffness tester method. At the time of sampling, it was cut out so that the direction of measuring the stiffness was the MD direction (machine flow direction).
For WET Taber stiffness, prepare a 38 mm wide and 70 mm long (MD direction long side) sample in advance as a test piece, soak it in water at 23 ° C for 30 seconds, and remove excess water with filter paper. Then, it measured according to JIS P 8125 Taber stiffness tester method.
(4) Clem water absorbency It measured according to the water absorptivity test method (Klem method) of JIS P8141. At the time of sampling, it was cut out so that the direction in which water permeates was MD (machine flow direction).
(5) Surface strength It measured according to the surface strength test method by the wax prescribed | regulated to JAPAN TAPPI No1.
(6) Submerged self-sustained test A test piece (width 50 mm, length 100 mm was fixed to a height of 8 mm in a bat filled with water at a height of 25 mm, and the self-standing time was measured. The sample was cut so that the MD of the sample had a long side (100 mm), and a schematic diagram is shown in FIG.
Judge that it can be used for more than 15 days.

(7) Water transpiration evaluation A sample of A4 size (sample width 297 mm x flow 210 mm) was prepared for water transpiration evaluation. As shown in FIG. 2, this was bent at three places to form a prismatic shape and fastened at three places with a stapler. Next, put distilled water in the aluminum tray so that the depth is 15 mm, put this prismatic sample in the aluminum tray, and put the total weight of the sample, aluminum tray, and water (each aluminum tray) It was measured. Next, this was left in a constant temperature and humidity (23 ° C., 50%) room for 3 days, and the weight after 3 days was measured again. The amount of water transpiration was converted to the amount of transpiration per hour according to the following formula.
Amount of water transpiration (g / hour) = {(total weight before leaving) − (total weight after leaving for 3 days)} / 72
For reference, the paper sample was not placed in the aluminum tray, and the result measured with only water in the aluminum tray was 0.96 g / hour.

(8) Printability Using an RI printing tester, ink was printed at Toyo Ink PRINTING INK SMX Tack Grade 20, ink amount: 1.5 g, printing rotation speed: 35 rpm / min, printing frequency: once, and paper was peeled off Evaluation was carried out according to the degree of.
(Evaluation)
○: No paper peeling △: Fluffing or fine paper peeling ×: Significant paper peeling

(Example 2)
Instead of adding 0.3 parts of anionic polyacrylamide (Polystron 117 manufactured by Arakawa Chemical Co., Ltd.) as a solid at the time of paper preparation, 0.4 parts of amphoteric polyacrylamide (Polystron 1250 manufactured by Arakawa Chemical Co., Ltd.) was added in solid form. In the same manner as in Example 1, paper having a basis weight of about 420 g / m ² was made, and paper quality measurement and evaluation as a transpiration paper were performed. The results are shown in Table 1.

Example 3
Instead of adding 0.6 parts of wet paper strength enhancer (manufactured by Starlight PMC, WS4024) in solid form at the time of preparing the stock, 1.5 parts of anionic polyacrylamide (Polystron 117 made by Arakawa Chemical Co., Ltd.) in solid form was added to the solid solution. A paper having a basis weight of about 420 g / m ² was made in the same manner as in Example 1 except that 0.75 part was added instead of adding 3 parts, and the paper quality was measured and evaluated as a transpiration paper. The results are shown in Table 1.

Example 4
A paper having a basis weight of about 420 g / m ² was made in the same manner as in Example 1 except that the anionic polyacrylamide was not added at the time of preparing the stock, and the paper quality was measured and evaluated as a transpiration paper. The results are shown in Table 1.

(Example 5)
A paper having a basis weight of about 420 g / m ^{2 in} the same manner as in Example 1 except that 0.05 part of an emulsion sizing agent (Harsize NES747 manufactured by Harima Kasei Co., Ltd.) was added in solid form during paper stock preparation. Made. The degree of sizing of the base paper measured in accordance with JIS P 8122 was 5 seconds. After that, a non-ionic surfactant (Takemoto Yushi Co., Ltd.) was added to a 1.2 g / m ² solid anionic polyacrylamide resin (Arakawa Chemical Industries Polymer Set 512) as a paper strength enhancer using a rod coater on one side of the base paper. Co., Ltd., Pionein K17) was applied so that it was 0.2 g / m ^{2 in} solid form. Paper quality was measured and evaluated as a transpiration paper. The results are shown in Table 1.

(Example 6)
After making paper with a basis weight of about 420 g / m ² , 0.6 g / m ² instead of 1.2 g / m ^{2 in} solid form with anionic polyacrylamide resin (Arakawa Chemical Industries Polymer Set 512) using a rod coater. A sample was obtained in the same manner as in Example 5 except that coating was performed, and paper quality measurement and evaluation as a transpiration paper were performed. The results are shown in Table 1.

(Example 7)
After making paper with a basis weight of about 420 g / m ² , 1.6 g / m ² instead of 1.2 g / m ² solid anionic polyacrylamide resin (Arakawa Chemical Industries Polymer Set 512) with a rod coater. A sample was obtained in the same manner as in Example 5 except that coating was performed, and paper quality measurement and evaluation as a transpiration paper were performed. The results are shown in Table 1.

(Example 8)
A pulp slurry of 40% NBKP and 60% cotton linter pulp was mixed and beaten with a double disc refiner (DDR) so that the Canadian standard freeness was 500 cc. Subsequently, 0.1 part of solid aluminum sulfate is added to 100 parts of solid pulp, 0.3 part of anionic polyacrylamide (Arakawa Chemical Co., Ltd. Polystron 117), and a wet paper strength enhancer ( Starlight PMC, WS4024) was added in a solid form of 0.6 part, and emulsion size (Harima Kasei, Hersize NES747) was added in a solid form of 0.1 part to prepare a paper stock. Using this stock, a paper having a basis weight of about 420 g / m ² was made with a long paper machine. The degree of sizing of the base paper measured according to JIS P 8122 was 9 seconds. After that, an anionic polyacrylamide resin (Polymerset 512 manufactured by Arakawa Chemical Industry Co., Ltd.) as a paper strength enhancer as a paper strength enhancer is 1.2 g / m ^{2 in} solid form on one side of the base paper with a rod coater, and a nonionic surfactant (manufactured by Takemoto Yushi) A sample was obtained by coating pionein K17) so as to be 0.2 g / m ^{2 in} solid form, and a paper quality measurement and evaluation as a transpiration paper were performed. The results are shown in Table 1.

(Comparative Example 1)
About 420 g of basis weight in the same manner as in Example 1 except that the wet paper strength enhancer (manufactured by Starlight PMC, WS4024) and an anionic polyacrylamide (Polystron 117 manufactured by Arakawa Chemical) are not added during the preparation of the stock. / M ² paper was made, and the paper quality was measured and evaluated as a transpiration paper. The results are shown in Table 1.

(Comparative Example 2)
A paper with a basis weight of about 420 g / m ² was made in the same manner as in Example 4 except that 0.6 part of the wet paper strength enhancer was added instead of adding 0.6 part of the wet paper strength enhancer, and the paper quality was measured. And evaluated as transpiration paper. The results are shown in Table 1.

(Comparative Example 3)
The basis weight was about the same as in Example 5 except that 1.0 part was added instead of adding 0.05 part of solid emulsion sizing agent (Harsize NES747 manufactured by Harima Kasei Co., Ltd.) during paper stock preparation. A paper of 420 g / m ² was made. The degree of sizing of the base paper measured according to JIS P 8122 was 430 seconds. After that, a non-ionic surfactant (Takemoto Yushi Co., Ltd.) was added to a 1.2 g / m ² solid anionic polyacrylamide resin (Arakawa Chemical Industries Polymer Set 512) as a paper strength enhancer using a rod coater on one side of the base paper. Co., Ltd., Pionein K17) was applied so that it was 0.2 g / m ^{2 in} solid form. Paper quality was measured and evaluated as a transpiration paper. The results are shown in Table 1.

(Comparative Example 4)
A pulp slurry of 40% NBKP and 60% cotton linter pulp was mixed and beaten with a double disc refiner (DDR) so that the Canadian standard freeness was 500 cc. Subsequently, 0.1 part of solid aluminum sulfate was added to 100 parts of solid pulp to prepare a paper stock. Using this stock, paper having a basis weight of about 420 g / m ² was made with a long paper machine, and the paper quality was measured and evaluated as a transpiration paper. The results are shown in Table 1.

Claims (6)

The main component is wood pulp or non-wood pulp, and the water absorption of Klem specified in JIS P 8141 containing wet paper strength agent and polyacrylamide is 40 mm or more, and the Wet Taber stiffness is 3.0 mN · m or more. A transpiration paper that is self-supporting in a state of water absorption. The transpiration paper according to claim 1, wherein the polyacrylamide is anionic. The transpiration paper according to claim 1 or 2 , wherein a surface strength agent is applied to the surface of the paper, and the surface strength measured by the method of JAPAN TAPPI No. 1 is 10A or more. A method for producing a transpiration paper, characterized by adding a wet paper strength agent and polyacrylamide to a pulp slurry containing wood pulp or non-wood pulp as a main component and making paper. A pulp slurry mainly composed of wood pulp or non-wood pulp was added with an internal sizing agent, a wet paper strength agent, and polyacrylamide, and the paper was made into a paper sheet having a sizing degree of 10 measured according to the JIS P 8122 Steech human size test method. A method for producing a transpiration paper, comprising: applying a surface coating solution containing a surface paper strength agent and a surfactant to a paper base material having a duration of less than 2 seconds. 6. The method for producing a transpiration paper according to claim 4, wherein the polyacrylamide is anionic.

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