JP2015163742A - sanitary paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sanitary paper such as toilet paper, tissue paper, paper towel and the like that is soft and excellent in touch feeling, and is excellent in water dispersibility as well.SOLUTION: The sanitary paper that is soft and excellent in touch feeling and is excellent in water dispersibility as well is produced by incorporating chemical pulp having a hemicellulose content of 2-10 mass%, preferably dissolving kraft pulp having a hemicellulose content of 2-10 mass%.

Description

  The present invention relates to sanitary paper such as toilet paper, tissue paper, paper towel, and the like, and more particularly to a sanitary paper that is soft and excellent in touch feeling and excellent in water dispersibility.

  Conventionally, as pulp used for so-called sanitary paper such as toilet paper, tissue paper, paper towels, etc., slush pulp in a slurry state produced from chemical pulp obtained by digesting wood chips from hardwood and conifers ( slushed pulp), dry pulp obtained by dehydrating and drying this slush pulp, or deinked waste paper pulp obtained by deinking waste paper, these pulps are unbleached pulp, It is used in the state of bleached pulp, or in the state of unbeaten and beaten pulp, alone or in combination depending on the quality design.

  Research has been conducted on techniques for improving the softness and touch feeling, which are important quality of tissue paper, for example, laminated tissue paper in which the type of pulp to be laminated and papermaking and its use ratio are adjusted, and a method for producing the same (Patent Document 1, Patent Document 2), by appropriately selecting a paper machine such as a long net, a short net, a twin wire, a circular net Yankee machine, or a paper softener such as a fatty acid ester softener (Patent Document) 3), quaternary ammonium salt type cationic surfactant (Patent Document 4), urethane alcohol or a salt thereof, or cationized product (Patent Document 5), non-cationic surfactant (Patent Document 6, Patent Document 7) , Polyphosphate (Patent Document 8), polysiloxane (Patent Document 9, Patent Document 10) and other additive chemicals are added to slush pulp. Various methods have been proposed, such as a method of improving the slip of the loop itself to make it softer and softer, and a method of bending the fiber by adding a mechanical kneading treatment after concentrating the pulp (Patent Documents 11 and 12). ing.

  The method using the additive chemicals may provide a good softening effect, but because of its high foaming property, there is a risk of hindering the paper making operation itself. In some cases, the paper strength and water absorption are reduced. There was a problem of inviting. In addition, when the fiber is bent by mechanical treatment, there is a problem that it is disadvantageous in terms of energy because the raw material concentration step is excessively increased.

  Conventionally, in order to improve the smoothness of the surface, one or two calendars made of a pair of fully polished chilled rolls and metal rolls are used after the tissue paper machine. However, when the linear pressure is increased in order to improve smoothness with this calendar, there is a problem that the thickness becomes thin and rigid, and the touch feeling becomes stiff.

JP 54-46914 A Japanese Utility Model Publication No. 4-66992 US Patent 3,296,065 Japanese Patent Laid-Open No. 48-22701 JP 60-139897 JP-A-2-99690 JP-A-2-99691 JP-A-2-36288 JP-A-2-224626 JP-A-3-900 JP-A-5-23262 Japanese Patent Laid-Open No. 6-14848

  An object of the present invention is to provide a sanitary paper that is soft and has a good touch feeling, is excellent in strength, and is excellent in water dispersibility.

  As a result of intensive studies, the present inventors can obtain a sanitary paper that is soft and has good touch feeling and excellent water dispersibility by containing chemical pulp having a hemicellulose content of 2 to 10% by mass. As a result, the present invention has been completed.

  According to the present invention, it is possible to obtain a sanitary paper that is soft, excellent in touch, and excellent in water dispersibility.

  The sanitary paper of the present invention is characterized by containing a chemical pulp having a hemicellulose content of 2 to 10% by mass, preferably 2.5 to 6.5% by mass. Sanitary paper containing chemical pulp with a hemicellulose content of more than 10% by mass is inferior in flexibility and touch and inferior in water dispersibility. In addition, the sanitary paper containing chemical pulp having a hemicellulose content of less than 2% by mass has a significant decrease in strength.

  As a method for producing chemical pulp having a hemicellulose content of 2 to 10% by mass, a method for decomposing hemicellulose by subjecting kraft pulp obtained by ordinary kraft cooking to a strong alkali treatment or an enzyme treatment, a sulfite method And dissolved kraft pulp obtained by kraft cooking of wood chips subjected to hydrothermal treatment. Dissolved kraft pulp is hydrothermally treated to the wood chips before kraft cooking so that hemicellulose in the wood can be released as water-soluble sugar, so the resulting pulp is usually not hydrothermally treated Compared to kraft pulp (KP), the content of hemicellulose is extremely low. Although the hemicellulose content of ordinary kraft pulp (KP) is about 12 to 30% by mass, the hemicellulose content of the dissolved kraft pulp used in the present invention depends on the type of plant material used, but 2 to 10 mass%. %.

  Below, the method to manufacture a melt | dissolution kraft pulp is demonstrated.

  Dissolved kraft pulp (DKP) is dissolved pulp produced by the kraft cooking method (KP method), and its raw material is wood chips. In the present invention, it is preferable to include wood chips made of softwood, and the size and tree species are not particularly limited, and may be a single kind of wood chip or a chip in which two or more kinds of wood are mixed. In the present invention, a high-quality dissolving pulp can be efficiently produced even if it is a softwood species that is relatively difficult to digest or bleach. As a softwood chip used in the present invention, for example, a larch genus or a pine genus wood chip can be suitably used. For example, Larix (hereinafter abbreviated as L.) leptolepis (larch), L. laricina (Tamarac), L. occidentalis (Larix larch), L. decidua (European larch), L. gmelinii (Guimatsu) Etc. Examples of conifers other than the genus Larix include Pinus radiata for the genus Pinus, Pseudotuga (hereinafter abbreviated as P.) menziesii (Dacrasfer), P. japonica, For example, Cryptomeria japonica can be mentioned for the genus Sugi.

  In the present invention, hardwood wood chips can be used as a raw material. As a hardwood wood chip, for example, a Eucalyptus wood chip can be suitably used. For the Eucalyptus genus, Eucalyptus (hereinafter abbreviated as E.) calophylla, E. citriodora, E .; diversiccolor, E.I. globulus, E.I. grandis, E .; gummifera, E .; marginata, E.M. nesophila, E.I. nitens, E.I. amygdalina, E .; camaldulensis, E .; delegenasis, E.I. gigantea, E .; muelleriana, E.M. obliqua, E .; regnans, E .; Sieberiana, E.I. viminalis, E .; camaldulensis, E .; marginata and the like.

Hydrothermal treatment step In the present invention, as a pretreatment before kraft cooking, hydrothermal treatment is performed on the chips to decompose and remove the hemicellulose content in the wood chips into water-soluble sugars. Hydrothermal treatment (prehydrolysis) as pretreatment is performed by treating wood chips with high-temperature water. The water to be added may be hot water or steam. Since an organic acid or the like is generated by the progress of hydrolysis, the pH of the treatment liquid is generally 2 to 5.

  The hydrothermal treatment is preferably performed in a temperature range of 150 to 180 ° C. If temperature is less than 150 degreeC, removal of hemicellulose will become inadequate, and when it exceeds 180 degreeC, hydrolysis will become excess and alpha-cellulose content will also fall. The treatment time is not particularly limited, but is preferably 15 to 400 minutes, more preferably 20 to 250 minutes, and even more preferably 25 to 150 minutes. When the treatment time is too short, the removal of hemicellulose becomes insufficient, and the delignification improving effect due to the removal of hemicellulose is also reduced. On the other hand, if the treatment time is too long, hydrolysis will be excessive and the α-cellulose content will be reduced, resulting in a decrease in pulp yield, and condensing of lignin will lead to deterioration in digestibility in the subsequent kraft cooking process. .

  In the hydrothermal treatment in the present invention, the treatment temperature and treatment time can be set using the P factor (Pf) as an index. The P-factor is a standard indicating the total amount of heat given to the reaction system in the prehydrolysis treatment, and is expressed by the following formula in the present invention, and time integration is performed from the time when chips and water are mixed until the end of cooking. To calculate.

Pf = ∫ln ⁻¹ (40.48-15106 / T) dt
[Wherein T represents an absolute temperature at a certain point]
The hydrothermal treatment in the present invention is desirably performed in the range of P factor (Pf) of 50 to 900, preferably 150 to 900, and more preferably 500 to 800. If Pf is less than 50, the removal of hemicellulose becomes insufficient, the effect of improving delignification due to the removal of hemicellulose is reduced, and the content of hemicellulose in the pulp after kraft cooking in the subsequent step is 10% by mass. It will exceed. On the other hand, when Pf exceeds 900, hydrolysis becomes excessive and the α-cellulose content is reduced, leading to a decrease in pulp yield, and condensing of lignin leads to deterioration of digestibility in the subsequent kraft cooking process. .

  The hydrothermal treatment step can be performed by putting wood chips and water in a pressure resistant container (prehydrolysis kettle), but the shape and size of the container are not particularly limited.

  The ratio when supplying wood chips and water to the hydrothermal treatment tank (prehydrolysis tank) is preferably 1 to 2.3 L / kg. The ratio of wood chips to water supplied to the prehydrolysis kettle is also called the dynamic liquid ratio and is shown as the amount of water per kg of wood chips. If the dynamic liquid ratio is less than 1.0 L / kg, the amount of water is too small relative to the wood chips, resulting in insufficient hydrolysis. If the liquid ratio exceeds 2.3 L / kg, the top of the prehydrolysis tank In this case, it is not preferable because the gas phase portion cannot be sufficiently secured. The water includes not only water supplied with the wood chip but also water contained in the wood chip, drain water, and the like.

  Moreover, the ratio of the wood chip and water in the prehydrolysis kettle can be, for example, 1.0 to 5.0 L / kg, preferably 1.5 to 4.5 L / kg, and 2.0 to 4.0 L / kg is more preferable. If the liquid ratio is less than 1.0 L / kg, hydrolysis is insufficient because the amount of water is too small relative to the wood chips, and if the liquid ratio exceeds 5.0 L / kg, the size of the container becomes excessive. Therefore, it is not preferable. Moreover, you may add a small amount of mineral acid as needed.

Chip Cleaning / Recovery Step Next, the pre-hydrolyzed wood chip is recovered by removing the pre-hydrolyzed solution and thoroughly washing the chip with water. Insufficient cleaning can cause adverse effects in subsequent cooking steps.

  Washing and removal of the hydrolyzed liquid can be performed by using a general solid-liquid separator. For example, a solid-liquid separation device such as an extraction screen or filter cloth is provided in a container used for prehydrolysis, and washing water is introduced from the lower part of the container and extracted from the screen for countercurrent washing.

The chips after washing the kraft cooking process are put together with the cooking liquor into the digester and used for kraft cooking. Moreover, you may use for cooking of correction craft methods, such as MCC, EMCC, ITC, and Lo-solid. Also, there are no particular limitations on cooking types such as 1 vessel liquid phase type, 1 vessel gas phase / liquid phase type, 2 vessel liquid phase / gas phase type, and 2 vessel liquid phase type. That is, the step of impregnating and holding the alkaline aqueous solution of the present application may be installed separately from the conventional apparatus or part for the permeation treatment of the cooking liquid. Preferably, the unbleached pulp that has been cooked is washed with a washing device such as a diffusion washer after extracting the cooking liquor. The kappa number of the unbleached pulp after washing is preferably 7-15, and may be 9-13.

  The kraft cooking process can be performed by putting the pre-hydrolyzed wood chips together with the kraft cooking liquid in a pressure resistant container, but the shape and size of the container are not particularly limited. The liquid ratio between the wood chip and the chemical solution can be, for example, 1.0 to 5.0 L / kg, preferably 1.5 to 4.5 L / kg, and more preferably 2.0 to 4.0 L / kg. .

  Moreover, in this invention, you may add the alkaline cooking liquid containing 0.01-1.5 mass% quinone compound per absolutely dry chip | tip to a digester. If the addition amount of the quinone compound is less than 0.01% by mass, the addition amount is too small to reduce the kappa number of the pulp after cooking, and the relationship between the kappa number and the pulp yield is not improved. Furthermore, the reduction of wrinkles and the suppression of the decrease in viscosity are insufficient. Moreover, even if the addition amount of a quinone compound exceeds 1.5 mass%, the further reduction of the kappa number of the pulp after cooking and the improvement of the relationship between a kappa number and a pulp yield are not recognized.

  The quinone compound used is a quinone compound, hydroquinone compound or precursor thereof as a so-called known cooking aid, and at least one compound selected from these can be used. Examples of these compounds include anthraquinone, dihydroanthraquinone (for example, 1,4-dihydroanthraquinone), tetrahydroanthraquinone (for example, 1,4,4a, 9a-tetrahydroanthraquinone, 1,2,3,4-tetrahydroanthraquinone). Methyl anthraquinone (eg 1-methyl anthraquinone, 2-methyl anthraquinone), methyl dihydroanthraquinone (eg 2-methyl-1,4-dihydroanthraquinone), methyl tetrahydroanthraquinone (eg 1-methyl-1,4,4a) , 9a-tetrahydroanthraquinone, 2-methyl-1,4,4a, 9a-tetrahydroanthraquinone) and the like, anthrahydroquinone (generally 9,10-dihydroxyanthracene), Tyranthrahydroquinone (for example, 2-methylanthrahydroquinone), dihydroanthrahydroanthraquinone (for example, 1,4-dihydro-9,10-dihydroxyanthracene) or an alkali metal salt thereof (for example, disodium salt of anthrahydroquinone, 1 , 4-dihydro-9,10-dihydroxyanthracene disodium salt), and precursors such as anthrone, anthranol, methylanthrone, and methylanthranol. These precursors have the potential to convert to quinone compounds or hydroquinone compounds under cooking conditions.

When the wood chip is a conifer, the cooking solution preferably has an active alkali addition rate (AA) per weight of the dry wood chip of 16 to 22% by mass. If the active alkali addition rate is less than 16% by mass, the removal of lignin and hemilulose becomes insufficient, and if it exceeds 22% by mass, the yield and quality are reduced. Here, the active alkali addition rate is obtained by converting the total addition rate of NaOH and Na ₂ S as the addition rate of Na ₂ O, and multiplying NaOH by 0.775 and Na ₂ S by 0.795. Therefore, it can be converted into the addition rate of Na ₂ O. The degree of sulfidation is preferably in the range of 20 to 35%. In the region where the sulfidity is less than 20%, the delignification property is lowered, the pulp viscosity is lowered, and the drought rate is increased.

  Kraft cooking is preferably performed in a temperature range of 120 to 180 ° C, more preferably 140 to 160 ° C. If the temperature is too low, delignification (decrease in the kappa number) is insufficient, while if the temperature is too high, the degree of polymerization (viscosity) of cellulose decreases. The cooking time in the present invention is the time from when the cooking temperature reaches the maximum temperature until the temperature starts to decrease, and the cooking time is preferably 60 minutes or more and 600 minutes or less, and 120 minutes or more and 360 minutes or less. Is more preferable. If the cooking time is less than 60 minutes, pulping does not proceed, and if it exceeds 600 minutes, the pulp production efficiency deteriorates, which is not preferable.

  Moreover, the kraft cooking in this invention can set process temperature and process time by setting H factor (Hf) as a parameter | index. The H factor is a standard representing the total amount of heat given to the reaction system during the cooking process, and is represented by the following equation. The H factor is calculated by time integration from the time when chips and water are mixed until the end of cooking.

Hf = ∫exp (43.20-16113 / T) dt
[Wherein T represents an absolute temperature at a certain point]
In the present invention, the unbleached (unbleached) pulp obtained after cooking can be subjected to various treatments as necessary. For example, bleaching can be performed on unbleached pulp obtained after kraft cooking.

  In one embodiment, oxygen delignification treatment can be performed on pulp obtained by kraft cooking. As the oxygen delignification used in the present invention, a known medium concentration method or high concentration method can be applied as it is. In the case of the medium concentration method, the pulp concentration is preferably 8 to 15% by mass, and in the case of the high concentration method, it is preferably performed at 20 to 35% by mass. As the alkali in oxygen delignification, sodium hydroxide and potassium hydroxide can be used. As oxygen gas, oxygen from a cryogenic separation method, oxygen from PSA (Pressure Swing Adsorption), VSA (Vacuum Swing Adsorption) Oxygen etc. from) can be used.

The reaction conditions for the oxygen delignification treatment are not particularly limited, but the oxygen pressure is 3 to 9 kg / cm ² , more preferably 4 to 7 kg / cm ² , the alkali addition rate is 0.5 to 4% by mass, and the temperature is 80%. ~ 140 ° C, treatment time is 20 to 180 minutes, and other conditions can be applied. In the present invention, the oxygen delignification treatment may be performed a plurality of times.

  The pulp that has been subjected to the oxygen delignification treatment is then sent to a washing step, and after washing, it is sent to a multistage bleaching step to perform a multistage bleaching treatment. The multi-stage bleaching treatment of the present invention is not particularly limited, but acid (A), chlorine dioxide (D), alkali (E), oxygen (O), hydrogen peroxide (P), ozone (Z), It is preferable to combine a known bleaching agent such as peracid and a bleaching aid. For example, the first stage of the multistage bleaching process uses a chlorine dioxide bleaching stage (D) or an ozone bleaching stage (Z), the second stage is an alkali extraction stage (E), the hydrogen peroxide stage (P), the third stage or later. A bleaching sequence using chlorine dioxide or hydrogen peroxide is preferably used. The number of stages after the third stage is not particularly limited, but considering energy efficiency, productivity, etc., it is preferable to finish in three or four stages in total. Further, a chelating agent treatment stage with ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) or the like may be inserted during the multistage bleaching treatment.

  In the present invention, the blending ratio of the chemical pulp having a hemicellulose content of 2 to 10% by mass with respect to the total pulp content is not particularly limited. However, the higher the blending ratio, the more flexible and hygienic sanitary paper is obtained. . From that viewpoint, 5 mass% or more is preferable with respect to the absolute dry weight of all the pulp, 30-100 mass% is more preferable, 60-100 mass% is still more preferable. If the blending ratio is less than 5% by mass, no change is seen in the softness and touch feeling, and the water dispersibility cannot be improved.

  The sanitary paper is composed of one layer or a plurality of layers, but chemical pulp having a hemicellulose content of 2 to 10% by mass may be made alone in one layer or a plurality of layers, and within the scope of the present invention. Pulp with different hemicellulose content may be mixed for paper making. Furthermore, conventional slush pulp, dry pulp, deinked pulp (DIP) may be mixed with chemical pulp with hemicellulose content of 2-10% by mass. You may make paper.

  The sanitary paper of the present invention may contain pulp other than chemical pulp having a hemicellulose content of 2 to 10% by mass. As a pulp other than chemical pulp having a hemicellulose content of 2 to 10% by mass, dissolved kraft pulp, kraft pulp (conifer bleached kraft pulp (NBKP) or unbleached kraft pulp (NUKP) with a hemicellulose content exceeding 10% by mass , Hardwood bleached kraft pulp (LBKP)) or unbleached kraft pulp (LUKP), etc.), mechanical pulp (groundwood pulp (GP), refiner mechanical pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp ( CTMP) etc.) and pulp such as deinked pulp (DIP) may be mixed and used at an arbitrary ratio.

  In the case where two sanitary papers composed of a plurality of layers are overlapped and stacked, if the layers containing chemical pulp having a hemicellulose content of 2 to 10% by mass are stacked on the outside, the feeling of touch is further improved. Further, when a layer containing a chemical pulp having a hemicellulose content of 2 to 10% by mass is pressed against a Yankee dryer and dried so that the surface is placed on the outer side of the hygienic paper superposed on two sheets, the touch is further increased. A feeling improves.

  The sanitary paper of the present invention can be made by a known method and apparatus. As a paper machine for sanitary paper, for example, a Yankee machine such as a circular net, a short net, or a twin wire can be used. The Yankee machine means a paper machine having a Yankee dryer, and is generally used for manufacturing sanitary paper such as tissue paper. A general printing paper is dried by a multi-cylinder dryer in which a large number of metal cylinders are connected, whereas a Yankee dryer used for manufacturing sanitary paper dries the paper by a cylinder having a relatively large diameter. Application of crepe to sanitary paper can also be performed by a general method. For example, wet crepe or dry crepe may be attached on a Yankee dryer, or wet crepe may be attached and further dry crepe may be attached. In addition, the sanitary paper of the present invention may be cut into an appropriate size according to the application, and may be a multi-ply sanitary paper in which a plurality of papers are stacked. It is also free to add perforations or the like to the sanitary paper of the present invention. In a preferred embodiment, two to three sheets can be stacked to store sanitary paper in a box to obtain a sanitary paper in a box.

  As the papermaking method, for example, both the method of mixing all pulp and making paper as a uniform single layer, and the papermaking method of superposing two or more layers, which are so-called laminated type sanitary paper, into one sheet are applicable. can do. In addition, when manufacturing sanitary paper by multilayer papermaking, it is preferable to use a double-layer sanitary paper from the viewpoint of formation. If three or more layers are laminated, the formation may deteriorate and the quality may deteriorate.

  The sanitary paper of the present invention is a paper that is mainly used for hygiene and menstrual use and has excellent disposable absorbency. Examples thereof include toilet paper, tissue paper, paper towels, Watting, and dust paper. . In general, toilet paper has good dispersibility in water and is often processed into a roll. In the present invention, even though it has a cardboard core, it has no core and can be used to the end. (Non-core roll) may be used. In many cases, tissue paper is multi-ply from the viewpoint of softness and strength, and box tissue in a box such as cardboard and pocket tissue in a container such as a film are typical. In general, tissue paper has higher water resistance than toilet paper. Examples of paper towels include kitchen towels, nursing towels, hand towels, and table napkins.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited by these. In addition,% in an Example and a comparative example shows the mass% unless there is particular notice.

Pulp prepared in the following examples and comparative examples was paper-made with a twin-wire type three-layer Yankee paper machine. The crepe was applied by measuring the speed difference between the dryer and the take-up reel. Unless otherwise noted, stack the two sheets so that the surface (YD surface) of the tissue paper base sheet in contact with the Yankee dryer is on the outside (the side that touches the user's hand), and this surface is on the outside. The dried surface in contact with the Yankee dryer was soft calendered.
The evaluation methods used in Examples and Comparative Examples are as follows.
-Water dispersibility: According to JIS P 4501.
-Touch feeling: Ten panelists evaluated the touch feeling and touch feeling. Displayed in the following categories.
Very good; ◎, good; ○, normal; △, bad; ×
Measurement of basis weight: According to JIS P 8124: 1998 (ISO 536: 1995).
-Amount of hemicellulose: Measured according to NREL / TP510-42618.

<Adjustment of dissolved kraft pulp 1>
Radiata pine wood chips were sieved using a sieve (gyro shifter) to obtain wood chips of size 9.5 to 25.4 mm.
Using a rotary autoclave, water was added to this wood chip so that the liquid ratio became 3.2 (L / kg), and pre-hydrolysis was performed at a pre-hydrolysis temperature of 170 ° C. for 30 minutes and at a P factor of 550. .
After completion of the pre-hydrolysis, the chip and the pre-hydrolyzed liquid were separated with a 300 mesh filter cloth, and hand-washed with 30 ° C. warm water at 60 ° C. for 15 seconds.
Subsequently, using a rotary autoclave again, the kraft cooking chemical solution was infiltrated at 150 ° C. for 85 minutes, and then cooked at a cooking temperature of 158 ° C. for 210 minutes and H-factor (Hf) = 1500. The chemical solution had an active alkali addition rate (AA) of 16.5%, an active alkali of 105 g / L (Na ₂ O conversion value), NaOH of 75.6 g / L (Na ₂ O conversion value), Na ₂ S of 29.4 g / L ( Na ₂ O conversion value) and a composition having a sulfidity of 28%, the liquid ratio of the wood chip to the cooking chemical was 3.2 (L / kg).
After digestion, the obtained unbleached pulp is subjected to oxygen delignification treatment, followed by chlorine dioxide treatment (D ₀ ) -alkali extraction / hydrogen peroxide treatment (Ep) -chlorine dioxide treatment (D ₁ ). Bleached dissolved kraft pulp was obtained. The treatment conditions are as follows, and the amount of chemical added is based on the weight of the dry pulp. The amount of hemicellulose of the obtained bleach-dissolved kraft pulp was 3.0%.
・ Oxygen delignification treatment: Pulp concentration 10%, oxygen addition amount 3.5%, sodium hydroxide addition amount 3.0%, magnesium oxide addition amount 0.04%, temperature 98 ° C., 60 minutes. Chlorine dioxide treatment (D ₀ ): Pulp concentration 10%, chlorine dioxide addition amount 1.2%, temperature 55 ° C., 60 minutes, alkali extraction / hydrogen peroxide treatment (Ep): pulp concentration 10%, sodium hydroxide addition amount 0.93% Hydrogen peroxide addition amount 1.03%, temperature 70 ° C., 90 minutes, chlorine dioxide treatment (D ₁ ): pulp concentration 10%, chlorine dioxide addition amount 0.66%, temperature 75 ° C., 240 minutes

<Adjustment of dissolved kraft pulp 2>
Bleached dissolved kraft pulp was produced in the same manner as dissolved kraft pulp 1 except that prehydrolysis was performed at a prehydrolysis temperature of 168 ° C. for 3 seconds and P factor = 150. The resulting bleach-dissolved kraft pulp had a hemicellulose content of 6.1%.
<Adjustment of kraft pulp 1>
Bleached kraft pulp was produced in the same manner as dissolved kraft pulp 1 except that wood chips that were not subjected to prehydrolysis were used. The amount of hemicellulose in the obtained bleached kraft pulp was 13.9%.

<Adjustment of kraft pulp 2>
Commercial hardwood kraft pulp was used. The amount of hemicellulose was 18.5%.

[Example 1]
Paper was made with a twin-wire type three-layer Yankee paper machine. Dissolved kraft pulp 1 was used for the upper and lower layers of the three layers. Kraft pulp 1 was used for the middle layer material. The crepe was applied by measuring the speed difference between the dryer and the take-up reel. Stack the two sheets of tissue paper so that the surface (YD surface) in contact with the Yankee dryer is on the outside (the side that touches the user's hand). The dried surface was soft calendered to produce tissue paper.

[Example 2]
For the upper layer and lower layer raw materials, tissue paper was produced in the same manner as in Example 1 except that the dissolved kraft pulp 2 was used.

[Comparative Example 1]
About the raw material of the upper layer and the lower layer, except having used the kraft pulp 1, it manufactured the tissue paper like Example 1. FIG.
[Comparative Example 2]
Regarding the upper layer and lower layer raw materials, tissue paper was produced in the same manner as in Example 1 except that kraft pulp 2 was used.

  As shown in Table 1, the tissue papers of Examples 1 and 2 were good in both hand feeling and water dispersibility. On the other hand, the tissue paper of Comparative Example 1 is inferior in both hand feeling and water dispersibility, and the tissue paper in Comparative Example 2 is in touch with Example 2 but is inferior in water dispersibility. . That is, even if a softwood having a touch feeling inferior to that of a normal hardwood is used as a raw material, a tissue paper having an excellent touch feeling can be obtained in the embodiments of the present invention.

Claims (4)

A sanitary paper comprising chemical pulp having a hemicellulose content of 2 to 10% by mass. A sanitary paper comprising two or more paper layers, wherein at least one paper layer contains chemical pulp having a hemicellulose content of 2 to 10% by mass. The sanitary paper according to claim 1 or 2, wherein the chemical pulp having a hemicellulose content of 2 to 10 mass% is a dissolved kraft pulp. The sanitary paper according to any one of claims 1 to 3, wherein the content of the chemical pulp having a hemicellulose content of 2 to 10% by mass is 30 to 100% by mass based on the absolute dry weight of the whole pulp.