JP4633070B2 - Manufacturing method of sanitary thin paper - Google Patents

Description

The present invention relates to a method for producing sanitary thin paper, and more particularly to a method for producing sanitary thin paper suitable for tissue paper, toilet paper, and kitchen paper.

Hygienic thin paper used for products mainly used for wiping, wiping, and absorbing body fluids such as tissue paper, toilet paper, and kitchen paper is required to be bulky.
Conventionally, in this main sanitary thin paper, a bulking agent comprising a cationic special surfactant has been used to increase the bulk.
JP 2006-183188 A JP 2006-161192 A

However, since this type of bulking agent is fixed on the fiber surface and inhibits hydrogen bonding between the fibers, the paper strength is reduced.
Therefore, there is a detrimental effect that the amount of paper powder increases as it breaks easily.
Therefore, the main problem of the present invention is to provide a method for producing bulky sanitary thin paper without reducing paper strength, and a bulky sanitary thin paper obtained by the method.

The present invention, which has solved the above problems, is a papermaking raw material comprising a raw pulp, natural starch, and starch-absorbing water-soluble starch produced by a method of subjecting a starch derivative to a pregelatinization treatment and drying and pulverizing with a drum dryer. It is a method for producing sanitary thin paper, characterized in that the wet paper is dried and then dried with a dryer.
This water-absorbing and water-retaining starch swells due to water absorption, and further shrinks to a size before swelling when dried. Furthermore, it hardly exhibits adhesiveness during swelling or shrinking.
Therefore, the wet paper made of a papermaking raw material containing the raw material pulp and the water-absorbing water-retaining starch is in a state where the swollen water-absorbing water-retaining starch is interposed between the pulp fibers.
When the wet paper is dried with a dryer, the water-absorbing water-retaining starch loses the retained water and shrinks. At this time, since the adhesiveness is hardly exhibited, the contacting fibers are not attracted to each other. Therefore, voids are formed between the fibers, and a bulky and soft sanitary thin paper can be obtained.
And in this invention which forms the space | gap between fibers by expansion | contraction and shrinkage | contraction of water-absorbing water retention starch, since the hydrogen bond between fibers is not inhibited, the paper strength resulting from this does not fall. Accordingly, there is no adverse effect such as excessive breakage or an increase in the amount of paper dust.
Here, it is desirable that the water-absorbing water-retaining starch is added in an amount of 0.01 to 5.0 kg / t with respect to the raw material pulp in order to achieve cost and certain effects.
The raw pulp preferably has a ratio of NBKP to LBKP (NBKP / LBKP) of 0/100 to 60/40. Since NBKP has a larger fiber thickness than LBKP, the more NBKP, the higher the bulk.

  As described above, according to the present invention, a bulky sanitary thin paper manufacturing method and a bulky sanitary thin paper are provided.

Next, embodiments of the present invention will be described in detail below with reference to the drawings.
In the method for producing sanitary thin paper of the present invention, a papermaking raw material containing raw pulp and water-absorbing water-retaining starch is made into a wet paper and then dried with a drier.
The raw pulp and the water-absorbing water-retaining starch are mixed in a dry state or by adding the water-absorbing water-retaining starch after slurrying the raw material pulp. However, since the water-absorbing and water-retaining starch can be interspersed between the pulp fibers before expansion, it is preferable to mix in a dry state.
Here, in order to obtain a sanitary thin paper by making the papermaking raw material into a wet paper and drying it, it can be performed by a papermaking technique using a known papermaking machine.
That is, various well-known paper machines are used which comprise at least three parts: a wire part that substantially forms a papermaking material on wet paper, a press part that dehydrates wet paper, and a dryer part that dries dehydrated wet paper. be able to.
A known dryer can be used as the dryer. As the dryer, a Yankee dryer is particularly suitable.

Raw material pulp includes mechanical pulp such as groundwood pulp (GP), pressure-rise groundwood pulp (PGW), thermomechanical pulp (TMP), semi-chemical pulp (CP), high yield unexposed kraft pulp (HNKP) Chemical pulps such as softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), and used paper pulp such as deinking pulp (DIP) and waste pulp (WP).
The raw material pulp can be used by selecting one kind or two or more kinds. Preferably, a chemical pulp containing no filler or foreign matter is preferred. In particular, a material containing more LBKP (also referred to as L material or hardwood pulp) than NBKP (also referred to as N material or softwood pulp) is used. That is, a chemical pulp having a ratio of NBKP to LBKP (NBKP / LBKP) of 0/100 to 60/40 is preferable. Since NBKP has a larger fiber thickness than LBKP, the more NBKP, the higher the bulk.
Further, the raw material pulp may contain woody materials such as straw pulp, bamboo pulp, kenaf pulp, and herbs.

  On the other hand, in the papermaking raw material, as fibers other than pulp, polyester fibers such as polyethylene terephthalate, polybutylene terephthalate, and copolymers thereof, polyolefin fibers such as polyethylene, polypropylene, and polystyrene, acrylic fibers such as polyacrylonitrile, modacrylic, etc. Acrylic fibers such as nylon 6, polyamide 66 such as nylon 66, nylon 12, etc., polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, urethane fibers and other synthetic fibers, triacetate fibers, diacetate fibers, etc. Synthetic fibers, regenerated cellulose fibers such as viscose rayon, copper ammonia rayon, polynosic rayon, lyocell, etc., regenerated fibers spun from collagen, alginic acid, chitin, etc. in solution It can be included Manabu fibers. The polymer constituting the chemical fiber may be in the form of a homopolymer, a modified polymer, a blend, a copolymer or the like.

On the other hand, the water-absorbing and retaining starch in the present invention has at least the following feature (1), and preferably has the features (2) to (5).
(1) When swollen by water absorption and further dried, it shrinks to a size substantially before swelling, and hardly exhibits adhesiveness during swelling or shrinkage.
(2) Even when heated in the presence of swelling or in the presence of water, it is stable in a constant swelling state, and does not develop viscosity or disintegrate like ordinary starch.
(3) It absorbs 5 to 20 times as much water as dry, and swells to about 1.5 to 4 times the dry volume.
(4) The absorbed water does not release at some external pressure, and the water absorption-drying is reversible, and the water absorption capability is obtained even after the water once absorbed is dried.
(5) General properties are white to pale yellowish white fine powder, moisture content is 5 to 50%, and pH is 4 to 10. The amount of water absorption hardly changes depending on the type, concentration and pH of ions or salts contained in the water to be absorbed.
Such a water-absorbing starch is at least one of potato starch, corn starch, sweet potato starch, tapioca starch, natural starch such as sago starch, rice starch and amaranth starch, and starch derivatives such as etherification, esterification and crosslinking thereof. Is subjected to a known alpha process, and then dried by a drum dryer to form a powder.
Specific examples include specially pregelatinized starch, for example, trade name: pregelatinized starch KZR (manufactured by Nissho Kagaku Co., Ltd.).
On the other hand, it is good to set it as 0.01-5.0 kg / t with respect to raw material pulp as a compounding quantity of a water-absorbing water retention starch. If it is less than 0.01 kg / t, the effect may not be sufficiently exhibited. If it exceeds 5.0, the softness tends to be lost, and the entanglement between the fibers becomes weak and excessive paper strength reduction may be caused.

Next, a description will be given with reference to FIG.
First, when raw material pulp and water-absorbing water-retaining starch are mixed in a dry state, as shown in FIG. 1 (A), water-absorbing water-retaining starch is interspersed between pulp fibers before expansion.
Next, such raw pulp and water-absorbing water-retaining starch are mixed with water and appropriate additives to form a slurry, which is used as a papermaking raw material. The papermaking raw material is made into a wet paper state by a wire part of a papermaking machine. At this time, as shown in FIG. 1 (B), the water-absorbing and water-retaining starch expands to about twice as much as that during drying and pushes between the pulp fibers.
When the wet paper is dried by the dryer part, as shown in FIG. 1 (C), the water-absorbing water-resistant starch shrinks to form gaps between the pulp fibers, and thus the gaps between the fibers are wide. A bulky sanitary thin paper is obtained.
On the other hand, the sanitary thin paper produced by the production method of the present invention is particularly suitable for tissue paper, toilet paper, and kitchen paper. In this case, it is desirable that the paper thickness is 80 to 500 μm at 10 to 35 g / m ² , and the manufacturing method of the present invention can meet the requirements of these paper products.
Further, preferably, the softness is in the range of 0.5 to 6.0 g, and the dry tensile strength based on JIS P 8113 is 200 to 800 cN / width 15 mm × 250 mm in the longitudinal direction; 50 to 400 cN / 15 mm × 250 mm in the transverse direction. Range.
Within these numerical ranges, there is no sensation of softness and moderate flexibility. In addition to this, the present invention ensures the required strength during use and produces less paper dust.

Subsequently, since the water-absorbing and water-retaining starch used in the present invention was tested for water absorption and expansion and shrinkage associated with drying, the test contents and results are shown below.
First, one grain of water-absorbing water-retaining starch is sampled, and the size of the collected water-absorbing water-retaining starch before absorbing water, after absorbing water, and after drying is further measured with a laser microscope (V-9000). The volume when the starch particles were assumed to be spherical from the size was calculated and compared.
The results are as shown in Table 1 below.

From Table 1, it is recognized that the water-absorbing water-retaining starch used in this test expands about twice as much as it absorbs water, and further shrinks to about 1.2 times the size before absorption.
From the above, it is possible to form voids between the fibers by using the water-absorbing water-retaining starch and mixing it with the pulp fibers.

Next, the paper strength, bulkiness, and paper dust generation were evaluated for Examples and Comparative Examples.
Examples are papers made by the production method according to the present invention using water-absorbing water-retaining starch. Comparative examples were a conventional product to which a bulking agent was added and a thin paper to which neither water-absorbing water-retaining starch nor bulking agent was added. For each example, several examples with different pulp blending rates and additive amounts were prepared and evaluated.
The composition of each example is shown in Table 2 together with the test results.
The bulkiness was sensory evaluation.
In addition, the amount of paper dust is cut into a size of 197 mm in length and 229 mm in width for the thin paper according to each example, and the two sheets are overlapped and folded 160 sets in a pop-up form and stored in a general tissue carton. And the sample was taken out one by one from the taking-out port on the upper surface of the carton, and the total count of the paper powder having a particle diameter of 10 μm to 100 μm remaining in the carton was measured by a light scattering type automatic particle counter.

The examples made using the water-absorbing water-resistant starch felt a bulky feeling, had sufficient paper strength, and resulted in a small amount of paper powder.
On the other hand, in the comparative example, there were some items that could not be said to be sufficient for any of the items of bulkiness, paper dust suppression, and paper strength.
From this result, it can be said that according to the production method of the present invention, it is possible to produce a thin paper which is superior to the conventional examples in terms of bulkiness, paper strength and paper powder amount.

  The present invention can also be used for manufacturing paper other than thin paper.

It is an enlarged view of thin paper which shows the mechanism of gap formation typically.

  DESCRIPTION OF SYMBOLS 1 ... Pulp fiber, 2 ... Absorbent water retention starch, 3 ... Void.

Claims (3)

Raw pulp,
Natural starch, starch-retaining water-soluble starch produced by a method of subjecting to a pregelatinization treatment, drying with a drum dryer and pulverizing,
A method for producing sanitary thin paper, characterized in that the papermaking raw material is made into wet paper and then dried with a dryer.   The method for sanitary production of thin paper according to claim 1, wherein 0.01 to 5.0 kg / t of the water-absorbing and water-retaining starch is added to the raw material pulp.   The said raw material pulp is the manufacturing method of the sanitary thin paper of Claim 1 or 2 whose ratio (NBKP / LBKP) of NBKP and LBKP is 0 / 100-60 / 40.

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