JP2800595B2 - Tissue paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to tissue paper. More specifically, the present invention relates to a tissue paper that is soft and has a good touch.

[0002]

2. Description of the Related Art As is well known, thin household paper (hereinafter referred to as tissue paper) such as toilet paper, tissue paper, paper towel, etc. is soft,
It is desired that the material has a good touch feeling, high strength, elasticity, and excellent absorption. Conventionally, as pulp for tissue paper, slush pulp (Slushed pulp) in the form of a slurry produced from wood chips from hardwood and softwood, that is, chemical pulp obtained by digesting lignocellulosic material, and this slush Dry pulp (dry p) obtained by dewatering and drying pulp
ulp) and deinked waste paper pulp obtained by deinking waste paper are used.These pulp may be unbleached, bleached pulp or unbeaten, beaten pulp depending on the quality design. Are used alone or in combination.

[0003] In order to maintain the strength of the tissue paper, especially the tensile strength, softwood pulp having a long average fiber length and high tensile strength is used. However, softwood pulp is stiff and, when used alone, softness and feel are reduced. Hardwood pulp, on the other hand, is thin and supple, has good softness and feel, but is rarely used alone as tissue paper pulp due to its short average fiber length and low tensile strength. Therefore, in order to maintain the tensile strength and not to deteriorate the softness and the feeling of touch, it is common to use a softwood pulp in combination with a hardwood pulp and / or a deinked waste paper pulp.

Techniques for improving the softness and texture, which are important qualities of tissue paper, have been studied in the past. For example, laminated tissue paper in which the type of pulp to be laminated and made and the proportion of the pulp used are adjusted. Its production method (Japanese Patent Application Laid-Open No. 54-46914, Japanese Utility Model Application No. 2-11049), by appropriately selecting a paper machine such as a long net, a short net, a twin wire, a circular net Yankee machine, or a flexible paper machine. Agents such as fatty acid ester-based softening agents (US Pat. No. 3,296,065) and quaternary ammonium salt type cationic activators (JP-A-48-227).
No. 01), urethane alcohol or a salt thereof, or a cationized product (JP-A-60-139897).
Non-cationic surfactants (JP-A-2-99690, JP-A-2-99691), polyphosphates (JP-A-2-36288), polysiloxanes (JP-A-2-36288).
Various proposals have been made such as a method of adding an additive chemical such as 224626 and 3900 to slush pulp to improve the sliding of the slush pulp itself to improve the feel and soften the slash pulp. Although these methods may provide a good softening effect, they may hinder the paper making operation itself due to the large foaming property, and in some cases, lower the paper strength and water absorption. There was a problem.

In order to increase the wet strength of tissue paper, urea formaldehyde resin, melamine formaldehyde resin, polyamide, polyamine, epichlorohydrin resin and the like are known as paper wet strength agents for paper. In the case of (1), since a formaldehyde resin is disliked, a polyamide, a polyamine, and an epichlorohydrin resin are mainly used. However, there is a problem that the bond with the epoxy resin is very firm and not only insoluble in water, but also the tissue paper itself becomes rigid, and the points of softness and touch are reduced.

Conventionally, the surface smoothness is improved by using one or two sets of a calender comprising a pair of sufficiently polished chilled rolls and metal rolls, one each for the upper and lower sides, after a tissue paper machine. Is used. However, in this calendar, there is a problem that when the linear pressure is increased to improve the smoothness, the thickness becomes thin and rigid, and the touch feeling deteriorates.

[0007]

In view of this situation, the inventors of the present invention have conducted intensive studies on the problems in the production of tissue paper which is soft, comfortable to touch and excellent in strength. Degree (TAPPI T23
By focusing on the so-called fine fibers having a short fiber length and maintaining the fiber roughness and the fine fibers in a specific range, a tissue paper having improved flexibility and hand feeling can be obtained. The inventors have found that the present invention has been achieved. Accordingly, an object of the present invention is to provide a tissue paper which solves the above-mentioned drawbacks and has excellent softness and touch feeling and excellent strength.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a tissue paper containing cellulose pulp as a main raw material, wherein the pulp has a fiber roughness (TAPPI T234h).
m-84) is a tissue paper containing 30 to 70% by weight on a dry basis of hardwood pulp in the range of 3 to 8 mg / 100 m.

As the pulp of the present invention, unbleached slush pulp obtained by digesting hardwood by a known digestion method and the pulp having a moisture content of 3 to 25% based on the weight of the absolutely dried pulp.
Pulp obtained by re-dissolving dry pulp dried in water in the range described above, or the unbleached pulp having a Hunter whiteness of 80 to 9
Slush pulp bleached to 0% and pulp obtained by re-dissolving dry pulp in water in which the pulp has a moisture content of 3 to 25% based on the weight of the absolutely dried pulp can be used. (LBKP) is preferably used.

Regarding the fiber roughness of pulp, the fiber roughness refers to the weight of the fiber per unit length and is expressed in mg / 100.
It is represented by m. The correlation with the cross-sectional area of the fiber is strong, and a lower value indicates a thinner and more pliable fiber. Furthermore, according to the study of the present inventors, among pulp manufactured from the same hardwood material, the fiber length is 0.
So-called fine fibers of 2 mm or less have higher fiber roughness.
Therefore, hardwood pulp with less fine fibers is preferred. The reason for the high fiber roughness of the fine fibers has not been elucidated at present, and must be studied in the future.

The fiber roughness of the hardwood pulp used in the present invention is in the range of 3 to 8 mg / 100 m. If the fiber roughness exceeds 8 mg / 100 m, the effect of improving the feeling of touch, which is the object of the present invention, cannot be obtained, and as the fiber roughness increases, the tissue paper becomes rigid and the feeling of touch deteriorates.

On the other hand, even if the fiber roughness is lower than 3 mg / 100 m, no further improvement in softness and hand feeling can be expected, and further, in order to obtain a pulp having a fiber roughness of less than 3 mg / 100 m. Fine fibers with high fiber roughness must be removed, which requires sieving of the pulp, which is unsuitable because of the increased production costs associated with the installation and operation of the screen equipment.

The content of the fine fibers having a fiber length of 0.2 mm or less in the hardwood pulp used in the present invention is preferably in the range of 0.5 to 4.0% by weight. If the amount of the fine fibers exceeds 4.0% by weight, there is no effect of improving the feeling of touch. Even if the amount of the fine fibers is less than 0.5% by weight, no further effect of improving the feeling of touch can be expected.

The use ratio of the hardwood pulp of the present invention is in the range of 30 to 70% by weight on an absolutely dry basis, preferably in the range of 35 to 50% by weight. When the ratio of hardwood pulp exceeds 70 wt%, the strength of the tissue paper, in particular tensile-strength unsuitable for lowered. If the content of the hardwood pulp is less than 30% by weight, the tissue paper becomes rigid and the desired effect cannot be obtained, which is not suitable.

As the pulp used in combination with the hardwood pulp of the present invention, unbleached slush pulp obtained by digesting softwood by a known digestion method and the pulp having a moisture content of 3 to 25% based on the weight of the absolutely dry pulp are used. Pulp obtained by re-dissolving dry pulp in water within the above range, or slush pulp obtained by bleaching the unbleached pulp to a Hunter brightness of 80 to 90%, and pulp having a moisture content of 3 to 25 per weight of the absolutely dried pulp % Of dry pulp dried in water and / or deinked waste paper pulp obtained by deinking waste paper. Of these, softwood bleached kraft pulp (NBKP) is particularly preferred. Is preferably used.

As a tissue paper machine, a Yankee machine such as a circular net, a short net, and a twin wire can be used. A base paper of tissue paper can be obtained by applying wet crepe or dry crepe on a Yankee dryer, or applying wet crepe and then applying dry crepe. In the case of a boxed tissue paper or the like, two sheets thereof are stacked and processed by a calender comprising a pair of upper and lower metal rolls to produce tissue paper.

As the papermaking method, there are both a conventional papermaking method in which all pulp is mixed to form a uniform single layer and a papermaking method in which two or more layers, which are so-called laminated tissue papers, are laminated to form one sheet. Although it can be applied, the latter papermaking method is more preferred.

If three or more layers of laminated tissue paper are laminated, the texture may deteriorate and the quality may be degraded. Therefore, a two-layer tissue paper is currently the mainstream. Two layers of tissue paper, one of which contains hardwood pulp with low fiber roughness, the layer containing the pulp is dried in contact with the mirror surface of the Yankee dryer, and then the fiber roughness in contact with the mirror surface of the Yankee dryer If the two tissue papers are arranged such that the layer containing the low-hardwood pulp is on the outside, that is, the side that the user touches is on the outside, the touch feeling is further improved.

[0019]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but it should be understood that the present invention is not limited thereto. Incidentally,% in Examples and Comparative Examples indicates% by weight unless otherwise specified. The evaluation methods used in the following Examples and Comparative Examples are as follows.

(2) Method for measuring fiber roughness (TAPPI T2
34 hm-84) A certain amount of a sample obtained by diluting unbeaten slush pulp or re-dissolved dry pulp is collected to obtain Kajaani FS-2.
The number of fibers and the number average fiber length are measured by a 00 automatic fiber length distribution measuring machine (manufactured by Valmet Automation),
The absolute dry weight of the pulp, which was separately measured by multiplying the number of fibers by the number average fiber length, was divided to obtain a unit of mg / 100 m.

Method for measuring the amount of fine fibers A certain amount of a sample obtained by diluting unbeaten slush pulp or re-dissolved dry pulp is sampled, and the Kayani FS-
The fiber length is measured for each layer divided by length using a 200 automatic fiber length distribution measuring device (manufactured by Valmet Automation Co., Ltd.). It is a calculated value assuming that the weight per unit length is proportional to the length.

Measurement method of tensile strength (JIS P81)
13-76) Two-ply tissue paper was cut into a width of 25 mm in parallel with the flow direction (longitudinal direction), and a length of 100 mm was set on a Tensilon universal tensile tester (manufactured by Toyo Bold-in Co.) to determine the breaking strength. Measure.

(2) Softness measurement method (J. TAPPI paper and pulp test method No. 34-80, test method for softness of thin tissue paper for sanitary use) A sheet of tissue paper (200 × 200 mm) is placed in a fixed gap (6.35 mm). Multiply the value measured by Handle-O-Meter (manufactured by Kumagaya Riki Kogyo Co., Ltd.) based on the principle of measuring the amount of work required to push in by 0.5, and the unit is g / 10 cm
And The test piece is pushed in at right angles to the flow of the sample.

(4) Touch feeling Sensory evaluation was performed on five boys and five women, and the results were displayed in the following categories. ◎: very good, 〇: good, △: normal, ×: bad

The pulp used in Examples 1 to 6 and Comparative Examples 1 to 6 was slush pulp of LBKP, slush pulp of NBKP, and dry pulp made from these pulp, and was used at a freeness of 560 ml. These raw pulp materials are added with a wet strength agent (Kaimen K-130).
0, manufactured by Dick Hercules Co., Ltd., 0.10% per weight of absolutely dry pulp,
The LBKP layer and the NBKP layer are laminated by making a paper with a laminating type Yankee paper machine, and the LBK is formed.
Drying was performed so that the P layer was in contact with the mirror surface of the Yankee dryer.

The crepe was provided by taking the difference in speed between the dry crepe and the dryer and take-up reel. The basis weight of the tissue paper made is 13.5 g / m
Adjusted to be ² . The textured tissue paper was evaluated as a textured tissue paper in which two sheets of the LBKP layer in contact with the mirror surface of the Yankee dryer were placed on the outside, and the texture was touched.

In Examples 7 and 8 and Comparative Example 7,
LBKP and NBKP were mixed and used at a freeness of 550 ml, and a wet paper strength enhancer (Kaimen K)
-1300 (trade name, manufactured by Dick Hercules Co., Ltd.) was added in an amount of 0.08% based on the weight of the absolutely dried pulp, and paper was made using a twin-wire single-layer Yankee paper machine.

The crepe was provided by taking the difference in speed between the dry crepe and the dryer and take-up reel. The basis weight of the tissue paper made is 13.5 g / m
Adjusted to be ² . The texture was evaluated as a cosmetic tissue paper obtained by stacking two tissue papers so that the surface in contact with the mirror surface of the Yankee dryer was on the outside.

Example 1 The ratio of pulp used was 60% NBKP and L in dry bone pulp.
BKP 40%, NBKP is slush pulp, LB
KP has a fiber roughness of 7.6 mg / 100 m and a fine fiber of 1.9.
% Dry pulp (water before defibration, hereinafter referred to as water,
Tissue paper was produced using a raw material consisting of 6.1%).

Example 2 A tissue paper was produced in the same manner as in Example 1 except that NBKP was 50% and LBKP was 50%.

Example 3 A tissue paper was produced in the same manner as in Example 1 except that NBKP was 40% and LBKP was 60%.

Example 4 A tissue paper was produced in the same manner as in Example 1 except that the LBKP used was slush pulp having a fiber roughness of 5.0 mg / 100 m and a fine fiber of 0.9%.

Example 5 A tissue paper was produced in the same manner as in Example 1 except that the LBKP used was slush pulp having a fiber roughness of 6.3 mg / 100 m and fine fibers of 3.4%.

Example 6 A tissue paper was produced in the same manner as in Example 3, except that the NBKP used was dry pulp (water content: 4.5%).

Example 7 A tissue paper was produced in the same manner as in Example 1 except that the paper was made using a one-layer Yankee paper machine.

Example 8 A tissue paper was produced in the same manner as in Example 4 except that the paper was made with a one-layer Yankee paper machine.

Comparative Example 1 Tissue paper was produced in the same manner as in Example 1 except that the LBKP used was slush pulp having a fiber roughness of 9.6 mg / 100 m and a fine fiber of 5.7%.

Comparative Example 2 A tissue paper was produced in the same manner as in Example 2 except that the LBKP of Example 2 was a slush pulp having a fiber roughness of 9.6 mg / 100 m and a fine fiber of 5.7%.

Comparative Example 3 A tissue paper was produced in the same manner as in Example 3, except that the LBKP used was slush pulp having a fiber roughness of 9.6 mg / 100 m and a fine fiber of 5.7%.

Comparative Example 4 Tissue paper was prepared in the same manner as in Example 1 except that the LBKP used was dry pulp (water content: 5.5%) having a fiber roughness of 15.8 mg / 100 m and fine fibers of 9.4%. Was manufactured.

Comparative Example 5 Tissue paper was prepared in the same manner as in Example 1 except that the LBKP used was dry pulp having a fiber roughness of 10.2 mg / 100 m and fine fibers of 6.5% (water content: 8.7%). Was manufactured.

Comparative Example 6 Half of the LBKP of Example 1 (20% of the raw pulp) was slush pulp with a fiber roughness of 9.6 mg / 100 m and 5.7% of fine fibers, and the other half of the LBKP (20% of the raw pulp).
%) Has a fiber roughness of 7.6 mg / 100 m and a fine fiber of 1.9.
% Tissue paper was produced in the same manner as in Example 1 except that the dry pulp content was 0.1% (water content: 6.1%).

Comparative Example 7 Tissue paper was produced in the same manner as in Comparative Example 1 except that the paper was made with a one-layer Yankee paper machine. Hand feeling of 2-ply tissue paper of Examples and Comparative Examples, softness, by measuring the tensile strength of the results are shown in Table 1.

[0044]

[Table 1]

As is clear from the results of the examples in Table 1, LBKP having a fiber roughness of 3 to 8 mg / 100 m and a fine fiber content of 0.5 to 4.0% was used as a raw material pulp.
When used in the range of 0 to 70%, a tissue paper which is soft and has excellent touch feeling can be obtained. This is evident from the measured value of softness (horizontal), which indicates that the lower the numerical value, the more flexible. The tensile strength (vertical) is 350
There is no quality problem if it is more than g.

[0046] In contrast, those fiber roughness of pulp with high LBKP lot of fine fibers has a result of hand feeling is poor (Comparative Examples 2, 3, 4, 5 and 7),
Further, even when the use ratio of LBKP having a low fiber roughness is small, the effect of improving the feeling of touch is not obtained (Comparative Example 6).

[0047]

As is apparent from the above description, the present invention provides a tissue paper using pulp fiber as a main raw material by using a pulp having a low fiber roughness and a small number of fine fibers as a hardwood pulp as a main raw material. This is an effect that can be used as a strong tissue paper which is soft and excellent in touch.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-136426 (JP, A) JP-A-2-29222 (JP, A) JP-A-5-76644 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) A47K 10/16 D21H 15/02

Claims (1)

(57) [Claims] 1. A tissue paper produced using cellulose pulp as a main raw material, wherein the pulp has a fiber roughness (according to TAPPI T234hm-84).
Is in the range of 3 to 8 mg / 100 m, and the fiber length is 0.2 m
m in the range of 0.5 to 4.0% by weight.
Tissue paper it is characterized by containing 30 to 70 wt% of hardwood pulp absolute dry weight in.