JPH0970372A - Wet tissue - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet tissue which contains pulp fibers as a main constitutional fiber of a base fabric and does not generate yellowing even after it is left in the atmospheric condition for a long time and gives good dry touch after use and is suitable for varius uses for foods, sanitation and use, and the like. SOLUTION: This wet tissue prepd. by impregnating a base fabric for cleaning with an impregnation liq. for cleaning contains pulp fibers as a constitutional fibers for the base fabric and either 0.6-7.0wt.% sodium lactate or 0.2-6.0wt.% calcium chloride per total wt. of the impregnation liq. are incorporated in this impregnation liq.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet tissue composed of a cleaning base cloth and a cleaning impregnation liquid, and pulp used as a constituent fiber of the base cloth. More specifically, the present invention, in a wet tissue using pulp fibers as the constituent fibers of the cleaning base fabric, by suppressing and preventing yellowing of the pulp fibers in use, high white and good appearance, Further, the present invention relates to a wet tissue which has an excellent feel after use, is harmless and has high safety, and can be suitably used for various purposes such as food, hygiene and household.

[0002]

2. Description of the Related Art What is called a wet tissue is
It is a base cloth for cleaning that uses paper or pulp fiber, natural fiber, regenerated fiber, synthetic fiber, etc. and is impregnated with a solution in which various chemicals are added in combination. Generally, improvement of moisture retention and cleaning -Improved dirt removal effect and improved softness and feel. For example, a wet tissue containing a glycol solvent in order to improve the moisturizing property has been disclosed (JP-A-6-46968).
However, there is a problem that after using the wet tissue, it becomes sticky and the feel is not good. In addition, inorganic salts, soaps,
The use of organic antistatic agents is known (JP-A-61-5).
6656), the use of hygroscopic salts, polyhydric alcohols, saccharides, and water-retaining pastes is known for improving flexibility and touch feeling (JP-A-5-1).
56596).

However, conventionally, in a wet tissue in which pulp fiber is used as a constituent fiber of the base fabric, if one end of the tissue is protruded from the container and left in the air during use of the wet tissue,
The tip of the tissue turns yellow, which makes it very unattractive and has no commercial value. The occurrence of yellowing is a problem that occurs when pulp fibers having a high degree of whiteness are used, but no specific means or method for solving this problem has been proposed. Regarding the cause of yellowing of the wet tissue containing pulp fiber, the present inventors conducted an intensive analysis and investigation, and as a result of searching for the cause, the molecular weight derived from cellulose or hemicellulose remaining in the bleached pulp fiber was 300. A mixture of water-soluble sugar substances (disaccharides) of about ~ 400 moves and concentrates at the tip of the tissue as water evaporates from the tip, where it undergoes aerial oxidation to deteriorate and form colored groups. It was presumed that it formed and caused yellowing and was colored.

The decrease in whiteness of bleached pulp fibers under various conditions is also called color reversion, and many studies have been conducted so far. As a measure for preventing yellowing, pulp is cooked, bleached and dried. , Storage conditions adjustment (pulp bleaching, pages 311 to 342, paper pulp monograph series P
ART4, edited by Chugai Sangyo Kenkyukai) and a method of protecting the yellowing-causing component by reacting with various chemicals to prevent discoloration have been proposed. However, for food, hygiene,
Alternatively, in the case of wet tissue used for household use, it comes into direct contact with food, human skin and mucous membranes,
High safety is required, there are concerns about the safety of chemicals used to prevent yellowing of pulp fibers, and yellowing caused by the oxidative decomposition of sugars contained in pulp fibers is related to humidity. The technique for preventing pulp yellowing cannot be directly applied to a wet tissue used in a wet state because of the characteristic of being significantly accelerated by temperature. Furthermore, in recent years, environmental problems including the problem of dust are drawing attention, and although the use of pulp fibers, which are biodegradable materials, is strongly desired, the problem of yellowing of pulp fibers in wet tissues using pulp fibers can still be solved. No, and there is growing demand for a solution to this problem.

[0005]

In view of the present situation, the present inventor has conducted earnest research on the cause of yellowing of wet tissues using pulp fibers as the main constituent fibers of the base fabric and its suppression / prevention measures, and as a result, wet In order to prevent yellowing of tissue, it was concluded that this problem could be solved by inhibiting the oxidation of water-soluble disaccharides derived from cellulose and hemicellulose, which are the yellowing-causing components remaining in pulp fibers, and it was harmless. With high safety, a specific salt is added to the impregnating liquid for wet tissue from among inexpensive food additives,
It has been found that when the tissue is impregnated and used, it is possible to prevent yellowing of the wet tissue, and it is possible to obtain a wet tissue containing pulp fibers that has a good feel after use and is highly safe. The invention has led to the completion of the invention. Therefore, the object of the present invention is to solve the above-mentioned problems, to include pulp fibers as the main constituent fibers of the base fabric, yellowing does not occur even if left in the atmosphere, and the feeling of use after use is The purpose is to provide a good wet tissue.

[0006]

Means for Solving the Problems The present invention relates to a wet tissue in which a cleaning base cloth is impregnated with a cleaning impregnating liquid, and pulp fibers are contained as constituent fibers of the base cloth, and the impregnating liquid is Sodium lactate 0.6-
7.0% by weight or calcium chloride 0.2 to 6.0% by weight
It is a wet tissue characterized by containing any of the above.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The wet tissue of the present invention is
It is configured by impregnating a base fabric containing pulp fibers with a cleaning impregnating liquid containing a specific amount of either sodium lactate or calcium chloride. The base fabric may be in the form of a sheet containing pulp fibers, for example, a wet or dry paper sheet made from pulp fibers as a raw material, and synthetic short fibers such as polypropylene and polyester and pulp fibers as a raw material. Alternatively, a known pulp fiber such as a composite sheet obtained by interlacing fibers with a water jet stream of a dry papermaking sheet, a paper sheet, and a laminate of a spunbonded nonwoven fabric made of synthetic continuous filaments such as polypropylene and polyester. The containing sheet is used for the present invention. Examples of the pulp fiber used in the present invention include bleached softwood kraft pulp and bleached hardwood kraft pulp, and are not particularly limited.

[0008] The impregnating solution for wiping contains 0.6 to 7.0% by weight, preferably 1.5 to 7.0% by weight as an anhydride based on the total weight of the impregnating solution.
It contains 3.0% by weight of sodium lactate. If the content is less than 0.6% by weight, the yellowing-preventing effect of the wet tissue cannot be obtained, and if the content exceeds 7% by weight, the obtained effect is saturated, and the content tends to reach a peak with an increase in the content. Therefore, it is uneconomical. Similarly, the wiping impregnating liquid may contain 0.2 to 6.0% by weight, preferably 2.0 to 3.5% by weight, of calcium chloride as an anhydride based on the total weight. In this case, if the content is less than 0.2% by weight, the effect of preventing yellowing cannot be obtained, and if it exceeds 6.0% by weight, the obtained effect is saturated, and the content tends to reach a peak as the content increases. It is uneconomical.

The sodium lactate and calcium chloride used in the present invention are very hygroscopic and are commercially available in various states such as an aqueous solution, a hydrate and an anhydride. Since the effectiveness is the same, any of an aqueous solution, a hydrate and an anhydride may be used.

In the present invention, the impregnating liquid for wiping only needs to be contained in a wet tissue containing pulp fibers, whereby the wet tissue is partially exposed to the air for a long period of time, and the water content in the wet tissue is exposed to the atmosphere. Even if it volatilizes inside, it does not lead to drying, so yellowing of the pulp fibers can be prevented. The mechanism for preventing yellowing has not been fully clarified, but it is presumed as follows.

That is, in a wet tissue containing pulp fibers treated with an impregnating solution for wiping containing sodium lactate or calcium chloride, the sodium lactate or calcium chloride has a water retention property, so that yellowing occurs. Even if the water-soluble disaccharide derived from cellulose or hemicellulose in the pulp fiber, which is the causative component, is moved / concentrated to the part of the wet tissue where the water content is partially reduced (in many cases, it is actually the tip part), Since sufficient water content is maintained there, contact between the causative component of the yellowing and oxygen in the air is hindered and yellowing does not occur. Moreover, compared to conventional water retention agents such as glycol, even when sodium lactate or calcium chloride is added to the impregnating solution and impregnated into the wet tissue, it does not feel greasy after use and feels smooth. And the texture is maintained.

[0012]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Incidentally,% in the examples and comparative examples means% by weight unless otherwise specified.

Example 1 50% pine, 10% Douglas fir, 40 domestically mixed softwood
% Kraft pulp bleached with oxygen-chlorine-caustic soda sodium hypochlorite chlorine dioxide sequence bleached softwood kraft pulp 100% Hunter whiteness 82.0%, basis weight 29.0 g / m ² 20 cm x 2 of pulp sheet (Shin Oji Paper Co., Ltd., Kure Mill)
The sheet was cut into a square shape of 0 cm, and the sheet was made into a square sheet of 10 cm × 10 cm, which was formed by stacking four sheets of 2 squares, and was folded along the diagonal line of this sheet. An equilateral triangular sheet was prepared and used as a sample for testing the yellowing resistance of pulp.

Next, sodium lactate (Kanto Kagaku Co., Ltd., special grade reagent, 60% aqueous solution) was dissolved in pure water to obtain a 6% solid solution, which was used as an impregnating solution for wiping. In a bag made of polyethylene and immersed therein, and then immersing the obtained eight-ply isosceles triangular sheet, the triangular point portion including the folding center portion of the sheet is 2c.
Place the product so that it is only m out of the bag and exposed to the atmosphere, close the chuck except the exposed part, and keep the rest of the sheet from contact with the atmosphere. In this state, in a constant temperature dryer at 40 ° C for 96 hours. Held After that, the degree of yellowing of the exposed portion was visually evaluated, and ○ was not yellowed at all, Δ was slightly yellowed but not a problem in practical use,
Evaluation was made by marking × for those that turned yellow and could not be used practically.

Next, in order to test the feeling of touch after touching this solution, the hands of the tester were thoroughly washed with tap water and commercially available soap, the moisture of the hands was wiped off with a paper towel, and after drying, The hands were immersed in a 6.0% sodium lactate aqueous solution, dried, and evaluated. The touch feeling was evaluated by four testers, and a good one as a smoothness was indicated by a circle, and a thing giving a sticky and unpleasant feeling was indicated by a cross. However, when evaluated as x, it was marked as x.

Example 2 The anti-yellowing property and the touch feeling were tested and evaluated in the same manner as in Example 1 except that an aqueous solution of sodium lactate having a solid content of 0.6% was used.

Example 3 An anti-yellowing property and a touch feeling were tested in the same manner as in Example 1 except that an aqueous solution of calcium chloride (Kanto Kagaku, special grade reagent) having a solid content of 5.0% was used. evaluated.

Example 4 The anti-yellowing property and the touch feeling were tested and evaluated in the same manner as in Example 1 except that an aqueous solution of calcium chloride having a solid content of 0.2% was used.

Comparative Example 1 The anti-yellowing property and the touch feeling were tested and evaluated in the same manner as in Example 1 except that pure water was used without using any chemicals.

Comparative Example 2 The anti-yellowing property and the touch feeling were tested and evaluated in the same manner as in Example 1 except that an aqueous solution of sodium lactate having a solid content of 0.3% was used.

Comparative Example 3 The yellowing prevention property and the touch feeling were tested and evaluated in the same manner as in Example 1 except that an aqueous solution of calcium chloride having a solid content of 0.15% was used.

Comparative Example 4 Sodium carbonate having a solid content of 1.0% (manufactured by Wako Pure Chemical Industries,
The yellowing prevention property and touch feeling were tested and evaluated in the same manner as in Example 1 except that an aqueous solution of special grade reagent) was used.

Comparative Example 5 A yellowing preventive property and a touch feeling were tested in the same manner as in Example 1 except that an aqueous solution of propylene glycol (manufactured by Kanto Chemical Co., Ltd., special grade reagent) having a solid content of 5.0% was used. evaluated.

The results obtained are shown in Table 1.

[0025]

[Table 1]

As can be seen from the table, the wet tissue of the present invention can prevent the yellowing of the pulp fibers used for the base fabric, and the touch feeling after use is smooth and good. On the other hand, when no chemical is used in the impregnating liquid for wiping (Comparative Example 1), and when the amount of sodium lactate or calcium chloride used is small (Comparative Examples 2 and 3), the touch feeling is improved. Although excellent, the yellowing resistance of pulp fibers is poor, and even when sodium carbonate is used as a wetting agent (Comparative Example 4), the yellowing resistance of pulp fibers is poor, and propylene glycol is used as a water retention agent.
When the content is about 5.0%, the anti-yellowing property is poor and, in addition, stickiness occurs after use, and it is unsuitable for use as an impregnating solution for wiping a wet tissue (Comparative Example 5).

[0027]

EFFECTS OF THE INVENTION The present invention does not cause yellowing of pulp fibers even when a part of a wet tissue containing pulp fibers is left in the air for a long period of time, and is not sticky to the touch even if it is touched by the hand during use. And the effect of providing a wet tissue that is excellent in feeling.

Claims (1)

[Claims] 1. A wet tissue in which a wiping base cloth is impregnated with a cleaning impregnating liquid, contains pulp fibers as constituent fibers of the base cloth, and the impregnating liquid contains 0 sodium lactate per the total weight of the impregnating liquid. A wet tissue containing either 0.6 to 7.0% by weight or calcium chloride of 0.2 to 6.0% by weight.