JP4762846B2 - Household tissue paper and its manufacturing method - Google Patents

Description

  The present invention relates to a household thin paper and a method for producing the same. In particular, the present invention is a household thin paper with a good touch feeling that is produced by using pulp derived from cedar thinned wood, etc., which has not been actively used as a raw material for pulp. About.

It is desired that so-called household thin papers such as cosmetic tissue paper, toilet paper, paper towels, and the like are soft, comfortable to touch, strong, stretchable, and excellent in absorbency.
Conventionally, as pulp for household thin paper, deinked waste paper pulp (DIP) obtained by deinking hardwood, chemical pulp obtained from softwood, newspaper waste paper, high-quality waste paper, OA waste paper, etc. has been used. There are cases where chemical pulp is used in a slurry state (slush pulp) and slush pulp is once dehydrated and dried to dry pulp, and this pulp is disaggregated and used again. Depending on the quality design, it has been used in an unbleached or bleached pulp state, or in an unbeaten or beaten state depending on the quality design.

  Among the pulps used for household thin paper, dry pulp and DIP are pulp fibers that are subjected to heat and mechanical compression, so that the pulp fibers contract, curl, and kinking. It is well known that when these pulps are used, they feel good and feel soft because they have undergone shape changes such as (changes) and the like, and are keratinized (Patent Document 1). . However, when these pulps are used, there is a problem that the strength of household thin paper is lowered due to the keratinization of the pulp fibers. In addition, a process for drying pulp is necessary to produce dry pulp, and the manufacturing process of household thin paper becomes complicated and costly. Further, when DIP is used, ink is used even after bleaching. There were quality problems such as remaining.

  On the other hand, when slush pulp is used, there is a problem that it is superior in strength compared to dry pulp and DIP, but inferior in softness and hand feeling of household thin paper. As a method of improving the softness and feel of household thin paper using slush pulp, pulp is mechanically kneaded at a high concentration of 20% or more to impart compressibility (for example, Patent Document 2), or pulp fiber. Or hardwood pulp having a specific fiber roughness (Patent Document 3), or a paper softener such as a fatty acid ester softener (Patent Document 4), a quaternary ammonium salt type cationic activity. A method of adding chemicals such as an agent (Patent Document 5), urethane alcohol, or a salt thereof, or a cationized product (Patent Document 6), a polyphosphate (Patent Document 7), a polysiloxane (Patent Document 8) has been proposed. Yes.

  However, in each of the above methods, the manufacturing process is still complicated, or when the softening agent is added, even if a good softening effect is obtained, the foaming property is large at the papermaking stage. There is a risk that the work itself may be hindered, and in some cases, there is a problem that paper strength and water absorption are reduced.

  Also known is a method for improving the feel of household thin paper by modifying the pulp to be used by enzyme treatment. For example, a method using a cellulose-degrading enzyme (Patent Document 9) and a method using a xylan-degrading enzyme (Patent Document 10) are disclosed. However, even if these methods are used, when the fiber form of the pulp is inferior, the touch feeling of household thin paper may not be improved.

  In addition, a method for improving the feel of household thin paper by limiting the form of pulp fibers to be used, adding a softener internally, and adding a dispersant during papermaking has also been proposed (Patent Document 11). ). In Patent Document 11, the weight average fiber length of softwood pulp is in the range of 2.20 to 3.50 mm, the fiber roughness is in the range of 11.0 mg / 100 m to 20.0 mg / 100 m, and is 300 mesh or less. The amount of fine fibers is 10% or less, the weight average fiber length of hardwood pulp is in the range of 0.70 to 0.90 mm, the fiber roughness is in the range of 7.0 to 13.0 mg / 100 m, and 300 mesh It is described that if the following fine fiber amount is 10% or less and a softener is added internally, and further a dispersant is added at the time of papermaking, a household thin paper having a soft texture can be obtained. ing.

As described above, conventional tissue paper using pulp derived from common coniferous materials such as spruce and pine is mainly used to soften the stiffness of softwood pulp by using softeners, etc. Focusing on the characteristics that differ depending on the type, etc., there is almost no technology that eliminates the rigidity inherent in coniferous pulp simply by selecting and using certain characteristics, especially pulp having a fiber wall thickness in a certain numerical range.
JP-A-5-23262 Japanese Patent Laid-Open No. 5-98597 Japanese Patent Laid-Open No. 6-121753 JP-A-2-36288 JP-A-2-224626 JP 2006-136351 A JP-A-5-156596 Japanese Patent Laid-Open No. 7-109693 JP-A-5-148794 JP-A-8-206030 JP 2006-097191 A

  It is an object of the present invention to provide a household thin paper that is flexible, has a good touch feeling, and has high strength, and a method for producing the same.

As a result of various investigations on a thin paper for household use and a method for producing the same, the present inventors have found that it can be realized by using softwood pulp having as thin a fiber wall as possible. Furthermore, as a result of investigating the coniferous wood having such a form, it was found that the pulp obtained from the cedar wood has a thin fiber wall and is suitable as a pulp for household thin paper.
Conventionally, cedar has many coloring components in the heartwood part and is less used as a pulp raw material because it is inferior in digestibility and bleaching to other softwoods. However, it was also found that the heartwood part of young cedar wood has few coloring components, and the fiber wall is thin in addition to being inferior in digestibility and bleaching to other materials.

Japanese cedar is relatively easy to obtain as thinned wood, and recently, Japanese cedar has been harvested for replanting to varieties with less pollen and other tree species due to problems with hay fever. Since the amount of the cedar wood is increasing, and the use of such cedar wood, which has low utility value as timber, is urgently developed, it is very effective to use it as a raw material for recyclable paper. Thus, cedar as a pulp raw material is a supply source of pulp having the soft feeling, touch feeling, and tensile strength required for pulp for household thin paper, and its pulping is easy. As a result, the present invention has been completed. The present invention is an invention selected from the following inventions .

(1) Constituent pulp is composed of 30 to 70% by weight of softwood pulp and 70 to 30% by weight of hardwood pulp material. The softwood pulp has a length-weighted average fiber length of 1.3 to 2.1 mm and a fiber width of 25. It is a softwood chemical pulp containing 15% to 100% by weight, preferably 30% to 100% by weight, of softwood pulp satisfying the conditions of ˜35 μm and fiber wall thickness of 5.5 to 7.5 μm. Household tissue paper.

(2) The domestic thin paper according to (1), wherein the softwood chemical pulp is bleached chemical pulp.

(3) The household thin paper according to (1) or (2), wherein the softwood chemical pulp is beaten pulp.

(4) A softwood chemical pulp satisfying the conditions that the length-weighted average fiber length is 1.3 to 2.1 mm, the fiber width is 25 to 35 μm, and the fiber wall thickness is 5.5 to 7.5 μm is manufactured from a cedar material. The household thin paper according to any one of (1) to (3), wherein

(5) The thin paper for household use according to (4), wherein the pulp produced from the cedar wood is bleached chemical pulp produced from cedar wood having a mass of 50% or more by age 40 years or less.

(6) The thin paper for household use according to (4) or (5), wherein the cedar wood is a cedar thinning material.

(7) The thin paper is a softwood containing softwood pulp that satisfies the conditions of length-weighted average fiber length of 1.3 to 2.1 mm, fiber width of 25 to 35 μm, and fiber wall thickness of 5.5 to 7.5 μm. The thin paper for household use according to any one of (1) to (6), wherein the thin paper is a thin paper obtained by making a pulp slurry containing bleached chemical pulp and hardwood bleached chemical pulp.

(8) The thin paper contains conifer chemical pulp that satisfies the conditions of length-weighted average fiber length of 1.3 to 2.1 mm, fiber width of 25 to 35 μm, and fiber wall thickness of 5.5 to 7.5 μm. Any one of (1) to (7), wherein the paper layer is manufactured by combining a paper layer made of a conifer chemical pulp-containing slurry and a paper layer made of the hardwood chemical pulp-containing slurry. Household tissue paper as described.

(9) The thin paper produced by making the paper is a thin paper that has been dry-creped after being dried with the hardwood chemical pulp layer side in contact with the dryer surface (8 ) Household thin paper as described.

(10) J. et al. TAPPI Paper Pulp Test Method No. Any of (1) to (9), wherein the tensile strength of the thin paper measured by 34-2000 is 0.5N to 3.0N in the transverse condition and the softness is 15mN / 10cm to 35mN / 10cm Crab for household use.

(11) Length-weighted average fiber length is 1.3 to 2.1 mm, fiber width is 25 to 35 μm, fiber wall thickness is 5.5 to 7.5 μm, and freeness is 500 ml C.I. S. F. ~ 700 ml C.I. S. F. A softwood pulp slurry containing a softwood chemical pulp and a hardwood pulp pulp slurry are prepared and combined with a twin-wire type two-layer yankee paper machine to make a softwood pulp a paper layer composed of a layer and hardwood pulp integrally laminated, basis weight 10.0g ^/ m ² ~20.0g / m 2 of paper making registration paper layer composed of a hardwood pulp and dried in contact with the mirror surface of the Yankee dryer A method for producing household thin paper, comprising making thin paper.

(12) The softwood chemical pulp has 15 masses of pulp having a length-weighted average fiber length of 1.3 mm to 2.1 mm, a fiber width of 25 μm to 35 μm, and a fiber wall thickness of 5.5 μm to 7.5 μm. % To 100% by mass, preferably 30% to 100% by mass, The method for producing household thin paper according to (11).

(13) The softwood chemical pulp according to (11) or (12), wherein 50% by mass or more of the softwood chemical pulp is produced from cedar wood having an age of 40 years or less. Production method.

(14) J. of manufactured thin paper for household use TAPPI Paper Pulp Test Method No. 34- softness measured at 2000 is characterized by a 15mN / 10cm~35mN / 10cm (11) Household tissue paper manufacturing method according to any one of the - (13).

According to the present invention, a softwood pulp having a length-weighted average fiber length of 1.3 to 2.1 mm, a fiber width of 25 to 35 μm, and a fiber wall thickness of 5.5 to 7.5 μm is used as a softwood pulp material. Thus, there is provided a household thin paper which is strong and flexible and has a good feel on the surface of the thin paper containing the softwood pulp material.
As a method of obtaining a conifer pulp having the above fiber characteristics, there is a method of fractionating a corresponding fiber form from a general conifer pulp, but the fiber form originally matches the above conditions like cedar wood. The method of using coniferous timber as a raw material is simple, and using thinned cedar timber at a low age is also preferable from the viewpoint of effective use of thinned timber, and in turn contributes to the conservation of the forest environment by promoting thinning. It will be done.

  As pulp used for household thin paper of the present invention, hardwood, softwood, and further non-wood type lignocellulosic material such as kraft cooking, sulfite cooking, sulfide cooking, soda cooking, etc. Unbleached chemical pulp obtained by a cooking method combined with a cooking aid, chemical pulp obtained by bleaching unbleached chemical pulp with alkali oxygen, and bleached chemical pulp obtained by bleaching alkali oxygen bleached chemical pulp in multiple stages according to a known bleaching sequence Can be used. Typical examples include unbleached kraft pulp (UKP), kraft pulp after bleaching with alkaline oxygen (OKP), and bleached kraft pulp (BKP).

Generally, since softwood pulp is rigid, when it is used alone as a pulp for thin paper, a thin paper having poor softness and touch feeling can be obtained. On the other hand, hardwood pulp is a thin paper that is thin, pliable and soft and has a good touch feeling, but is a thin paper having a short fiber length and insufficient tensile strength. Therefore, in order to obtain a thin paper having a tensile strength and softness and touch feeling, it is preferable to use a softwood pulp and a hardwood pulp together, and a non-wood pulp is also used in some cases.
In the case of the household thin paper of the present invention, in order to give strength, particularly tensile strength and flexibility, the length-weighted average fiber length is 1.3 to 2.1 mm, the fiber width is 25 to 35 μm, and the fiber wall thickness is A softwood pulp containing 15 to 100% by weight, preferably 30 to 100% by weight, of conifer pulp of 5.5 to 7.5 μm in total softwood pulp is used in combination with hardwood pulp.

The softwood pulp used in the household thin paper of the present invention is unfavorable when the length weighted average fiber length is less than 1.3 mm because the strength is low, and when it exceeds 2.1 mm, the feeling of touch is poor. This is not preferable.
Moreover, in the softwood pulp whose fiber width is less than 25 μm, the strength is lowered, and when it exceeds 35 μm, the softness is impaired, and the touch feeling is also deteriorated.
Further, when the fiber wall thickness of the softwood pulp is less than 5.5 μm, the strength is lowered, and when it exceeds 7.5 μm, the softness is impaired, and the touch feeling is also deteriorated.

  As a method of obtaining the conifer pulp having the fiber form, there is a method of fractionating the conifer pulp based on the fiber form. However, it is reasonable and simple to use a softwood material whose fiber form originally meets the above conditions, such as cedar. In the case of cedar, the fiber wall tends to be thinner than other softwood materials, which is preferable. Cedar wood has a problem that the heartwood part contains a lot of extract components and the cost of pulping is high, but there is no problem because young thinned wood that is usually available has few extract components in the heartwood part. There is also an advantage that the fiber wall of the pulp is thin. Since low-age cedar wood having a tree age of 20 to 40 years can be obtained in large quantities as thinning material, thinning cedar material is preferably used.

  When kraft cooking is performed using cedar as a raw material, the degree of sulfidation of the kraft cooking liquid is 5 to 75%, preferably 15 to 45%, and the effective alkali addition rate is 5 to 30% by weight, preferably 10 -25% by weight and the cooking temperature is 130-170 ° C. The cooking method may be either a continuous cooking method or a batch cooking method, and when a continuous cooking kettle is used, it may be a modified cooking method in which a cooking solution is added at multiple points, and the method is not particularly limited.

  In cooking, a known cyclic keto compound as a cooking aid in the cooking solution to be used, for example, benzoquinone, naphthoquinone, anthrone, phenanthroquinone, and a nuclear substituent such as an alkyl group or amino group of the quinone compound, or the quinone compound A hydroquinone compound such as anthrahydroquinone, which is a reduced form of the above, and a 9,10-diketohydroanthracene compound that is a stable compound obtained as an intermediate of the anthraquinone synthesis method by the Diels-Alder method Or 2 or more types may be added and the addition rate is 0.001-1.0 mass% per the absolute dry mass of a wood chip.

In the present invention, the unbleached chemical pulp obtained by a known cooking method is delignified by a known alkaline oxygen bleaching through washing, rough selection and selection processes. As the alkaline oxygen bleaching method used in the present invention, a known medium concentration method or high concentration method can be applied as it is, but a medium concentration method which is currently used at a pulp concentration of 8 to 15% by mass is preferred.
In the alkali oxygen bleaching method by the medium concentration method, caustic soda or oxidized kraft white liquor can be used as an alkali, and oxygen gas is oxygen from a cryogenic separation method, oxygen from PSA (Pressure Swing Adsorption). Oxygen from VSA (Vacuum Swing Adsorption) can be used. The oxygen gas and alkali are added to a medium concentration pulp slurry in a medium concentration mixer, and after sufficient mixing, they are sent to a reaction tower capable of holding a mixture of pulp, oxygen and alkali for a certain period of time under pressure. Ligned.

  The oxygen gas addition rate is 0.5 to 3% by mass per the dry pulp mass, the alkali addition rate is 0.5 to 4% by mass, the reaction temperature is 80 to 120 ° C., the reaction time is 15 to 100 minutes, and the pulp concentration Is 8 to 15% by mass, and other conditions can be known conditions. In the present invention, in the alkaline oxygen bleaching step, it is a preferred embodiment that the alkali oxygen bleaching is continuously performed a plurality of times and delignification is promoted as much as possible. The pulp that has been subjected to alkaline oxygen bleaching is then sent to a washing step. After washing, the pulp is sent to a multistage bleaching process.

  Examples of bleaching chemicals used in the multistage bleaching process of the present invention include chlorine dioxide (D), alkali (E), oxygen (O), hydrogen peroxide (P), ozone (Z), and organic peracids. A bleaching aid containing a bleaching agent and a chelating agent such as ethylenediaminetetraacetic acid (EDTA) or diethylenetriaminepentaacetic acid (DTPA) can be mentioned. The bleaching stage used in the multistage bleaching process of the present invention is not particularly limited, but the first stage is a chlorine dioxide bleaching stage (D), an ozone bleaching stage (Z), or ozone bleaching and chlorine dioxide bleaching. A bleaching stage (Z / D) or the like in which two or more are combined is preferably used, and in the second stage, an alkali extraction stage (E), an oxygen-added alkali bleaching stage (E / O), or a hydrogen peroxide-added alkali An extraction stage (E / P) or an oxygen / hydrogen peroxide-added alkali extraction stage (E / OP) is used, and a combination of chlorine dioxide, hydrogen peroxide, etc. is preferably used in the third and subsequent stages. The bleaching conditions such as the addition rate, processing time, temperature, pulp concentration, pH, etc. of the bleaching chemicals used in the multistage bleaching process of the present invention are not particularly limited, and known conditions can be applied. it can.

The bleached pulp then needs to contain mainly softwood pulp with a length-weighted average fiber length of 1.3-2.1 mm, a fiber width of 25-35 μm, and a wall thickness of 5.5-7.5 μm. It will be beaten accordingly.
Beating of bleached pulp is performed with a single disc refiner, a double disc refiner, a beater or the like. The beating degree is preferably in the range of 450 ml to 600 ml in terms of Canadian standard dryness (CSF).

  The bleached softwood bleached chemical pulp is used in the manufacture of household thin paper in combination with hardwood bleached chemical pulp. Examples of hardwood pulp used in combination with the above-mentioned conifer pulp include eucalyptus globulus, eucalyptus grandis, eucalyptus eurofira, eucalyptus eurograndis, eucalyptus maldrensis, acacia mangum, acacia auricular formis, and acacia merancy. A material made of a material having a small fiber width and a thin fiber wall is preferably used. However, it is difficult to obtain the desired strength with hardwood pulp alone, and it is difficult to obtain the desired strength. If excessive strength is added, the softness of the thin paper is impaired. Used in combination with soft and soft softwood pulp with a length of 1.3 to 2.1 mm, fiber width of 25 to 35 μm, and fiber wall thickness of 5.5 to 7.5 μm. It is preferable.

  The softwood pulp and hardwood pulp are then made by a paper machine to form thin paper. As a papermaking method, a paper slurry is made by mixing a pulp slurry mixed with softwood pulp and hardwood pulp, and the paper is made into a uniform layer, and papermaking is made by combining the softwood pulp layer and the hardwood pulp layer into one thin paper. Any of the methods can be applied, but the latter papermaking method is common.

The mixing ratio of the softwood pulp and the hardwood pulp in the method of mixing all the pulp and making paper as a uniform layer is not particularly limited, and generally 70 mass of the softwood pulp in the total pulp material. % To 30% by mass, and hardwood pulp is in the range of 30% to 70% by mass.
When the blending ratio of the softwood pulp is less than 30% by mass, the tensile strength is lowered, and when it exceeds 70% by mass, both the flexibility and the feeling of touch are inferior.
Moreover, the mass ratio of the softwood pulp layer and the hardwood pulp layer of the two-layer laminated thin paper is not particularly limited, and in general, the softwood pulp layer / hardwood pulp layer = 40/60 to 60/40. It is a range.
When the usage rate of the softwood pulp increases beyond the above range, the flexibility is inferior, which is not preferable. When the usage rate is less than the above range, the tensile strength is insufficient, which is not preferable.

In the case of a papermaking method in which two layers are combined into a single thin paper, a hardwood pulp layer and a softwood pulp layer are combined by a twin-wire type two-layer Yankee paper machine. A sheet of tissue paper is produced by drying so that the layer of the layer touches the mirror surface of the Yankee dryer.
Further, the two tissue papers can be overlapped so that the softwood pulp layers face each other and the both surface sides become hardwood pulp layers to form a pair of tissue papers. It has become the target.

  In the present invention, a Yankee machine such as a circular net, a short net or a twin wire can be used as a paper machine for household thin paper. By applying wet crepe or dry crepe on a Yankee dryer, or by applying wet crepe and further applying dry crepe, a base paper for household thin paper can be obtained. For example, in the case of boxed cosmetic tissue paper, as described above, tissue paper is produced by stacking two sheets of tissue paper together and treating with a calendar composed of a pair of upper and lower metal rolls.

Since the textured tissue paper has a poor texture when the three or more layers are laminated, the quality of the tissue paper may be lowered. The tissue paper is divided into two layers, one of which contains hardwood pulp, the layer containing hardwood pulp is dried in contact with the mirror surface of the Yankee dryer, and then the layer containing hardwood pulp in contact with the mirror surface of the Yankee dryer is on the outside That is, when the two sheets of tissue paper are arranged so that the surface touched by the user is on the outside, the feeling of touch is further improved.
Laminated tissue paper is described in J. Org. TAPPI Paper Pulp Test Method No. 34- softness measured at 2000 35 mN / 10 cm or less, is preferably adjusted in the following numerical range 26 mN / 10 cm.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, of course, this invention is not limited at all by these. Moreover, the evaluation and evaluation method which were performed about the tissue paper obtained by each Example and the comparative example are as follows. In Examples and Comparative Examples, “part” and “%” mean “part by mass” and “% by mass” unless otherwise specified.

<Measurement of fiber form>
Using Kayani Fiber Lab (Mesto Automation Co., Ltd.), the pulp vertebral form (length weighted average fiber length, fiber width, fiber wall thickness) was measured.

<Tensile strength>
The tensile strength was measured according to JIS P8113.

<Softness>
J. et al. TAPPI Paper Pulp Test Method No. It was measured according to 34-2000 “Paper-Softness Test Method”. That is, the amount of work required to push a tissue paper sheet (200 × 200 mm) into a certain gap (6.35 mm) is measured by Handle-0-Meter (manufactured by Kumagai Riki Kogyo Co., Ltd.). Multiply by 0.5 and display in g / 10 cm. Note that the sample piece was pushed in at a right angle (longitudinal direction) with respect to the flow of the sample.

<Hand feeling>
Sensory evaluation was performed with 10 men and 10 women, and the results were displayed in the following categories.
○○○: Very good ○○: Very good ○: Good △: Normal ×: Bad

Example 1
As raw material pulp, it was used in a ratio of 60 parts of commercially available unbeaten hardwood bleached kraft pulp (manufactured by Cenibra, freeness 600 ml (CSF)) and 40 parts of self-made softwood bleached kraft pulp beaten to 600 m1 (CSF). As a self-made softwood bleached kraft pulp, a cedar pulp with a whiteness of 84.5% was bleached with a bleaching sequence of DE / 0-P-D after kraft digestion of 40-year-old cedar thinned wood, followed by bleaching with alkaline oxygen. used. In addition, the length weighted average fiber length, fiber width, and fiber wall thickness of cedar pulp were 1.49 mm, 29.6 μm, and 6.2 μm, respectively. A wet paper strength enhancer (trade name: Arafix 255, manufactured by Arakawa Chemical Industry Co., Ltd.) is added to each raw pulp slurry in an amount of 0.1% by mass based on the mass of the dry pulp, and then the extraction pH of the resulting tissue paper is adjusted. A paper stock whose pH was adjusted with a sodium hydroxide solution so as to be in the range of 6.6 to 7.4 was prepared, and it was 1700 m / min with a twin-wire type two-layer yankee paper machine. Paper is made at a speed, and a hardwood bleached kraft pulp layer and a softwood bleached kraft pulp layer are laminated and dried so that the hardwood bleached kraft pulp layer contacts the mirror surface of the Yankee dryer, and the basis weight is 11.3 g / m. ^2. A two-layer tissue paper having a ratio of 60:40 of hardwood bleached kraft pulp to softwood bleached kraft pulp was used. The obtained two-layer combined tissue paper is peeled off from the dryer surface by a creping doctor, and a speed difference is provided to the take-up reel to give 30% dry crepe, and then the two-layer combined tissue paper Two sheets of white paper kraft pulp layer in contact with the mirror surface of the Yankee dryer were placed on the outer side to produce a cosmetic tissue paper having a basis weight of 22.6 g / m ² .
Of the used softwood bleached kraft pulp, the length-weighted average fiber length is 1.3 to 2.1 mm, the fiber width is 25 to 35 μm, and the fiber wall thickness is 5.5 to 7.5 μm. Table 1 shows the ratio of the pulp, the tensile strength of the manufactured tissue paper, the measurement results of the softness, and the sensory evaluation results of the feel of the tissue paper.

Example 2
The basis weight of 22.6 g / m was the same as in Example 1 except that the raw material for the self-made softwood bleached kraft pulp of Example 1 was changed from 100% cedar to 50% cedar and 50% larch. ^Two tissue papers were produced. The length weighted average fiber length, fiber width, and fiber wall thickness of larch pulp were 2.60 mm, 36.1 μm, and 9.4 μm, respectively.
Of the used softwood bleached kraft pulp, the length-weighted average fiber length is 1.3 to 2.1 mm, the fiber width is 25 to 35 μm, and the fiber wall thickness is 5.5 to 7.5 μm. Table 1 shows the ratio of the pulp, the tensile strength of the manufactured tissue paper, the measurement results of the softness, and the sensory evaluation results of the feel of the tissue paper.

Comparative Example 1
A tissue paper having a basis weight of 22.6 g / m ² was produced in the same manner as in Example 1 except that the raw material of the in-house manufactured softwood bleached kraft pulp of Example 1 was changed from 100% cedar to 100% larch.
Table 1 shows the measurement results of the weight-weighted average fiber length, fiber width, fiber wall thickness, tensile strength of the manufactured tissue paper, softness, and sensory evaluation of the feel of the softwood bleached kraft pulp used.

Example 3
As raw material pulp, it was used in a ratio of 60 parts of commercially available unbeaten hardwood bleached kraft pulp (manufactured by Cenibra, freeness 600 ml (CSF)) and 40 parts of self-made softwood bleached kraft pulp beaten to 600 m1 (CSF). As a self-made softwood bleached kraft pulp, cedar thinned wood of 35 years old is kraft-distilled, then bleached with alkaline oxygen and bleached with a bleaching sequence of DE / 0-P-D. used. A wet paper strength enhancer (trade name: Arafix 255, manufactured by Arakawa Chemical Industry Co., Ltd.) is added to each raw pulp slurry in an amount of 0.1% by mass based on the mass of the dry pulp, and then the extraction pH of the resulting tissue paper is adjusted. A pulp slurry was prepared in which the pH of the papermaking system was adjusted with a sodium hydroxide solution so as to be in the range of 6.6 to 7.4, and it was 1700 m / min by a twin-wire type two-layer woven Yankee paper machine. Paper is made at a speed, and a hardwood bleached kraft pulp layer and a softwood bleached kraft pulp layer are laminated and dried so that the hardwood bleached kraft pulp layer contacts the mirror surface of the Yankee dryer, and the basis weight is 22.6 g / m. ^2. A two-layer tissue paper having a ratio of 60:40 of hardwood bleached kraft pulp to softwood bleached kraft pulp was used. The obtained double-layered tissue paper was peeled off from the dryer surface by a creping doctor, and a speed difference was provided between the take-up reel and 30% dry crepe was applied to produce a cosmetic tissue paper.
Of the used softwood bleached kraft pulp, the length-weighted average fiber length is 1.3 to 2.1 mm, the fiber width is 25 to 35 μm, and the fiber wall thickness is 5.5 to 7.5 μm. Table 1 shows the ratio of the pulp, the tensile strength of the manufactured tissue paper, the measurement results of the softness, and the sensory evaluation results of the feel of the tissue paper.

Comparative Example 2
A tissue paper having a basis weight of 22.6 g / m ² was produced in the same manner as in Example 3 except that the raw material of the in-house manufactured softwood bleached kraft pulp of Example 3 was changed from 100% cedar to 100% larch.
Of the used softwood bleached kraft pulp, the length-weighted average fiber length is 1.3 to 2.1 mm, the fiber width is 25 to 35 μm, and the fiber wall thickness is 5.5 to 7.5 μm. Table 1 shows the ratio of the pulp, the tensile strength of the manufactured tissue paper, the measurement results of the softness, and the sensory evaluation results of the hand feeling.

  As is apparent from Table 1, by using conifer pulp having a length weighted average fiber length of 1.3 to 2.1 mm, a fiber width of 25 to 35 μm, and a fiber wall thickness of 5.5 to 7.5 μm. It can be seen that household thin paper with high tensile strength, high flexibility, and good touch feeling can be obtained. In particular, it can be seen that it is preferable to frequently use cedar wood-derived softwood pulp having the above-mentioned pulp characteristics.

As described above, softwood pulp having a length-weighted average fiber length of 1.3 to 2.1 mm, a fiber width of 25 to 35 μm, and a fiber wall thickness of 5.5 to 7.5 μm, particularly pulp derived from cedar wood. By blending, it is possible to provide household thin paper with high strength, high flexibility, and good touch feeling.
In addition, since cedar wood, particularly young cedar wood, is suitable as a softwood pulp material having the above characteristics, it is possible to effectively use cedar thinned wood that is difficult to directly use for building materials, etc. Recently, due to the problem of Japanese cedar pollinosis, we use cedar wood that has been harvested regardless of age for replanting to varieties with less pollen or other tree species as a raw material for recyclable paper. In this way, conservation of the forest environment can be achieved at the same time.

Claims (6)

Coniferous pulp material is composed of 30-70% by weight of softwood pulp material and 70-30% by weight of hardwood pulp material, and the softwood pulp material is manufactured from cedar wood of which 50% by weight is 40 years old or less. 15 wt% to 100 wt% of conifer bleached chemical pulp that satisfies the conditions of length-weighted average fiber length of 1.3 to 2.1 mm, fiber width of 25 to 35 µm, and fiber wall thickness of 5.5 to 7.5 µm. Household thin paper characterized by being a softwood chemical pulp containing mass%. The household thin paper according to claim 1 , wherein the cedar wood of 40 years old or less is a cedar thinning material . The thin paper is a softwood bleached chemical pulp of 50% by mass or more manufactured from cedar wood having an age of 40 years or less. The weight-weighted average fiber length is 1.3 to 2.1 mm, the fiber width is 25 to 35 μm, and the fiber wall A paper layer made from a paper stock containing a softwood chemical pulp containing 15% by mass to 100% by mass of a softwood bleached chemical pulp satisfying a thickness of 5.5 to 7.5 μm as a pulp material, and the hardwood pulp The thin paper for home use according to claim 1 or 2, wherein the thin paper is made by combining with a paper layer prepared from a paper stock contained as a pulp material . 4. The household according to claim 3 , wherein the laminated thin paper is a thin paper obtained by dry-creping a laminated thin paper that is dried with the hardwood pulp layer side in contact with a dryer surface. Tissue paper. J. et al. TAPPI Paper Pulp Test Method No. The tensile strength of the thin paper measured by 34-2000 is 0.5N-3.0N in a horizontal condition, and softness is 15mN / 10cm-35mN / 10cm , The any one of Claims 1-4 characterized by the above-mentioned. Household tissue paper. Conifer bleached chemical pulp of which 50% by mass or more is manufactured from cedar wood that is 40 years old or less. Length-weighted average fiber length is 1.3 to 2.1 mm, fiber width is 25 to 35 μm, and fiber wall thickness is 5. Containing 15 to 100% by weight of softwood bleached chemical pulp satisfying the condition of 5 to 7.5 μm and containing softwood chemical pulp having a freeness of 500 ml C.S.F. to 700 ml C.S.F. as pulp material A softwood pulp slurry and a pulp slurry containing hardwood chemical pulp as a pulp material are prepared and combined with a twin-wire type two-layer yankee paper machine to form a softwood pulp layer and a hardwood pulp layer. Laminated and integrated, dried hardwood pulp layer in contact with mirror surface of Yankee dryer, basis weight 10.0g / m ² ~ 20.0g / m ² A method for producing household thin paper, comprising making a thin paper.