JP3150586B2 - Water disintegration sheet manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-disintegrable sheet which disperses or dissolves in water.

[0002]

2. Description of the Related Art Conventionally, wet wipes are well known.
In addition, water-dispersible or water-disintegrable sheet materials represented by wet wipes, which can be dispersed or dissolved and thrown away as they are thrown into water such as flush toilets, are well known. The water dispersibility and water disintegration referred to here are synonymous, and wet wipes having such properties have high strength when used in a wet state, and quickness when thrown into a large amount of water. High dispersibility is required. JP-A-1-168999 uses a sodium / calcium salt of water-insoluble carboxymethylcellulose or a sodium salt of carboxymethylcellulose in order to achieve both the strength and the dispersibility. 48-27
No. 605 discloses a papermaking method in which an aqueous alkali metal solution is sprayed on wet paper made using water-insoluble carboxymethylcellulose. JP-A-3-167
In Japanese Patent Publication No. 400, paper is formed by mixing an alkali metal salt of water-insoluble carboxymethyl cellulose with a stock. In JP-A-5-25792, a paper made by mixing an alkali metal salt of carboxymethyl cellulose with a stock is impregnated with a water-containing organic solvent containing a polyvalent metal ion.

[0003]

The carboxymethylcellulose and its salt used as a binder in the prior art generally change from water-insoluble to swellable as the degree of substitution (DS) and pH increase. , And become more water-soluble. When a sheet is formed using these carboxymethylcellulose or a salt thereof as a binder, uniform mixing with the fiber becomes difficult if the binder has a high swelling property. In some cases, the strength of the sheet does not improve as much as the amount used. Also, in the step of spraying the binder to the sheet formed later by spraying,
When the swellability of CMC is high, the viscosity of the aqueous solution becomes high, and uniform spraying becomes difficult.

An object of the present invention is to provide a method for producing a hydrolyzed sheet usable as wet wipes or the like, in which a required amount of carboxymethylcellulose and / or a salt thereof is efficiently attached to the sheet.

[0005]

According to the present invention, there is provided a water-dispersible fiber and a carboxymethyl cell.
Add a base to the dispersion with loin and / or its salt and dissolve
It is premised on a method of manufacturing a water-disintegrated sheet in which the prepared stock is disassembled into sheets.

[0006] On this assumption, the present invention is characterized.
Where the degree of substitution with water-dispersible fiber = 0.30 to 0.6
Water-swellable or water-insoluble having pH of 0 and pH ≧ 5.0
With carboxymethylcellulose and / or its salts
The carboxymethylcellulose and / or
Or 80-400% by weight of its salt, sodium carbonate
Prepare a stock by dissolving the water-dispersible fiber
The carboxymethyl cellulose and / or a salt thereof is
The concentration in the stock is adjusted to 0.5 to 5% by weight,
Prior to the sheeting of the stock, the stock is
To be left for at least 30 minutes after the addition of the metal.

[0007]

EXAMPLES The raw materials used in the production method according to the present invention include water-dispersible fibers that can be formed into a sheet together with carboxymethylcellulose and / or a salt thereof. It is preferable to use pulp fibers as the fibers, but not limited thereto. Natural fibers such as linen and wool, regenerated fibers such as rayon fibers, semi-synthetic fibers such as acetate, and synthetic fibers such as nylon and polyester are used. You can also. For these fibers, S. = 0.30
Low water swellable or water insoluble carboxymethylcellulose having a pH of ０．６0.60 and a pH ≧ 5.0 and / or a salt thereof are used as binder. In order to change such a binder to a highly water-swellable or water-soluble binder
Add sodium carbonate. The mixture of these fibers and the binder to which sodium carbonate has been added is formed into a sheet . This
As the means, a well-known papermaking technique, a wet nonwoven fabric manufacturing technique, a nonwoven fabric manufacturing technique using water jet, and the like can be used. The present invention will be described in more detail as follows.

Examples 1-5 Papermaking softwood pulp (NBKP) and carboxymethylcellulose and / or a salt thereof were mixed and dispersed in tap water, and a required amount of sodium carbonate was added and dissolved to obtain a stock. After leaving it to stand, it was paper-formed with a small test paper-making machine, and the obtained wet paper was heated to 110 ° C using a rotary drum type dryer.
For 90 seconds to obtain a dried sheet having a basis weight of 40 g / m ² . Propylene glycol / calcium chloride / ion-exchanged water = 30 / 0.5 / 6 as a chemical solution for wet wipes
The sheet was impregnated with the mixed liquid of 9.5 (weight ratio) by spraying 2.5 times the weight of the sheet, and left still at 20 ° C. for 24 hours to obtain a wet wipe. The wet wipes were evaluated for water dispersibility and wet tensile strength under the following conditions, and the effects of various conditions in the papermaking process on them were confirmed. The relationship between a series of examples and comparative examples is as shown in Table 1 and below. (1) Example 1 and Comparative Example 1 The effect of the amount of sodium carbonate added (% by weight) on the dry weight of carboxymethylcellulose and / or its salt is shown. (2) Example 2 and Comparative Example 2 The effect of carboxymethylcellulose and / or its salt on the degree of substitution (DS) and pH is shown. (3) Example 3 and Comparative Example 3 Pulp and carboxymethyl cellulose in paper stock and / or
Or the effect of the total amount (% by weight) with the salt is shown. (4) Example 4 and Comparative Example 4 The effect of the standing time after the addition of sodium carbonate is shown. (5) Example 5 and Comparative Example 5 The effect of the mixing ratio between pulp and carboxymethylcellulose and / or its salt is shown.

[0009]Evaluation of water dispersibility  10cm x 10cm wet wipes specimen
In a 300ml glass beaker containing 300ml of replacement water
Put in and stir with magnetic stirrer (rotation speed 600r
pm) and observe the dispersion state of the wet wipes over time
did. The observation results were evaluated as follows. A: The specimen is subdivided within 100 seconds. B: The specimen is subdivided within 200 seconds. C: The specimen does not subdivide within 200 seconds.

[0010]Evaluation of wet tensile strength  Wet wipes with a width of 25 mm and a length of 150 mm
Chuck interval 100mm, pulling speed 100mm / min
The tensile strength at the time of pulling was measured. Low breaking strength
If at least 300g, wet wipes are practically strong
There was no shortage.

Table 1 shows the evaluation results of the examples and comparative examples. From these results, (1) carboxymethylcellulose and / or a salt thereof was obtained from D.C. S. = 0.30
０．６0.60, pH ≧ 5.0 (Example 2), (2) The amount of sodium carbonate is from 10 to 40% by weight of carboxymethylcellulose and / or its salt.
(Example 1), (3) the weight ratio of pulp to carboxymethylcellulose and / or a salt thereof is preferably in the range of 98: 2 to 55:45, and (4) pulp. And carboxymethylcellulose and / or a salt thereof account for 0.5 in the stock.
To 5% by weight, and (5) the standing time after the addition of sodium carbonate is preferably 30 minutes or more.

[0012]

[Table 1]

[0013]

In the method for producing a hydrolyzed sheet according to the present invention, carboxymethylcellulose having low swellability or water-insolubility and / or a salt thereof is mixed with the water-dispersible fiber as a binder. It is easy to attach a binder. Such a binder becomes water-swellable or water-soluble after the water-dispersible fiber is formed into a sheet by the addition of sodium carbonate ,
It improves the wet strength of the water-disintegrated sheet, and when it is put into a large amount of water, dissolves quickly to enable dispersion of the water-disintegrated sheet.

Continuation of the front page (72) Inventor Toshiya Okubo 2-5-2-3-12, Kameno-ko, Kakegawa-shi, Shizuoka (56) References JP-A-6-192991 (JP, A) JP-A-3-167400 (JP, A JP-A-7-90795 (JP, A) JP-A-1-168999 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D21H 11/00-27/42 A47K 7 / 00

Claims (2)

(57) [Claims] 1. A water-dispersible fiber and carboxymethyl cellulose
Add a base to the dispersion with
The method of manufacturing a water disintegratable sheet which sheet the paper stock prepared Te, water-dispersible fibers and degree of substitution = 0.30 to 0.60 and pH
Water-swellable or water-insoluble carboxyme having ≧ 5.0
To the dispersion with chill cellulose and / or its salt
Of carboxymethylcellulose and / or a salt thereof
Add 80-400% by weight of sodium carbonate and dissolve
A water-dispersible fiber and the carboxy
Simethylcellulose and / or a salt thereof is contained in the stock.
Of the paper stock is adjusted to 0.5 to 5% by weight.
Prior to sheeting, the stock is added with the sodium carbonate
The above-mentioned manufacturing method, wherein the method is left standing for at least 30 minutes . 2. The method according to claim 1, further comprising the step of impregnating said wet sheet with a chemical solution for wet wipes.