JPH01207457A - Sanitary sheet - Google Patents

Abstract

PURPOSE:To obtain a sanitary sheet for surface material such as non-returnable diaper or sanitary napkin containing a fiber soluble in an alkali solution at specific ratio or above and capable of carrying out treatment dropping into a flush toilet with the alkali solution. CONSTITUTION:The aimed sanitary sheet obtained using (A) 30-100 pts.wt. fiber being carboxymethylxcellulose having 0.25-0.4 substitution ratio of carboxymethyl group and (B) 0-70wt.% other fiber (e.g., having 30-60mm fiber length) insoluble in alkali solution and causing no clogging of discharge pipe for toilet stool by dispersing the used other fiber even in case using other fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sanitary sheet, and more particularly, to a sanitary sheet that can be flushed into a flush toilet together with an alkaline solution, and is useful for disposable diapers and sanitary use. It is used as a surface material for napkins, a so-called liner placed on the surface of diapers, bed sheets, etc.

(Prior art and its problems) Conventionally, sanitary sheets made of fibers such as rayon/pulp bound with an alkali-soluble resin (binder) have been used as sanitary sheets that can be dispersed by flowing down with an alkaline solution into a flush toilet bowl. It is disclosed in Japanese Patent Publication No. 49-112742.

According to the prior art, the fiber itself does not dissolve, so depending on the amount of fiber constituting the sheet, it may clog the drain pipe of the flush toilet. Therefore, a sanitary sheet that solves these problems is desired.

The purpose of the present invention is to use fibers that are soluble in an alkaline solution as at least a specific amount of constituent fibers.
The object of the present invention is to provide a sanitary sheet that can solve the above problems.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the sanitary sheet according to the present invention is made of carboxymethyl cellulose with a degree of substitution of carboxymethyl groups of 0.25 to 0.4 and is soluble in an alkaline solution. Sen! It is composed of 1k30% by weight or more.

As the fibers soluble in the alkaline solution, carboxymethyl rayon, carboxymethyl cotton, and carboxymethyl valve are used.

In order to achieve the object of the present invention, it is essential to use at least 30% by weight of the fibers that are soluble in the alkaline solution. This fiber (below)

(referred to as the first fiber) may be used in an amount of 100% by weight,
In addition, the second fiber may be used in an amount of 30% by weight or more and 100% by weight or less, and the rest is insoluble in the alkaline solution.

When the second fiber is used, examples of the fiber include polyester, polypropylene, rayon, polyester-polybropylene composite fiber, and polyester-polyethylene composite fiber, either alone or in combination.

If the first fiber is less than 30% by weight, in this case the other weight% may be used as a second fiber, or the proportion of the first fiber dissolved in the alkaline solution is small, so that the Even if the first fiber is dissolved, the second fiber constituting the sanitary sheet cannot be sufficiently dispersed. By the way, as long as the first fiber is used in an amount of 30% by weight or more, and from the viewpoint of reducing the so-called "stickiness" of the sanitary sheet due to, for example, drained liquid, an appropriate amount of the second fiber can be used. preferable.

In order for the first fiber to be soluble in an alkaline solution, it is essential that the degree of substitution of its carboxymethyl group is from 0.25 to 0.4. If the degree of substitution is less than 0.25, it will not dissolve in alkaline solutions, and if it exceeds 0.4, the wet strength will decrease, so when used as a sanitary sheet, it will not break during use. arise.

In the case of a sanitary sheet in which a second fiber is mixed, the first fiber must be dissolved and the second fiber must be dispersed as a result, or the purpose of the present invention can be achieved by improving the dispersibility of the second fiber. In order to achieve this, it is necessary that the fiber length of the second fiber is 100+s layers or less, and generally, a fiber length of about 30 to 6 ha is used. This is because if the fiber length is 100 m, the fibers become entwined with each other and the dispersibility of the fibers becomes poor. In this respect, since the first fiber is soluble, there is no particular restriction on the fiber length.

There are no particular restrictions on the fineness of the first and second fibers, and the fineness of the first and second fibers is generally about 1 to 10 d.

Sanitary sheets can be manufactured by various known methods. For example, water needling method, needle punch method, melt bond method, paper making method, etc.

The alkaline solution is not particularly limited, and may include aqueous solutions of sodium hydroxide, ammonia, and sodium silicate salts.

(Examples) Example 1 This example shows that the first fiber constituting the sanitary sheet needs to be 30% by weight or more.

The first fiber has a carboxymethyl group substitution degree of 0.
．． 3. A carboxyrayon fiber with a fineness of 3d and a fiber length of 51 mm, and a polyester fiber with a fineness of 2d and a fiber length of 44 mm as the second fiber, and a polyester fiber with a fineness of 2d and a fiber length of 4.
A web is formed by mixing 4-shoe rayon fibers, and this is treated by water needling to give a fabric weight of 28.
I got a sheet of g/■2.

The wet strength and dispersibility in an alkaline aqueous solution of the obtained sheet were measured by the following methods.

After soaking a sample with a wet strength of 2001 in width and 15 ha in length in physiological saline, a 200 g weight was placed on the center of the sample.
When opposite sides of the sample were lifted with both hands, it was observed whether the sample would be torn by the weight.

In the table below, ○ marks indicate those that were not torn, and X marks indicate those that were torn.

Dispersibility in alkaline aqueous solution: 1.5 μl of a sodium hydroxide solution with an IN value of 0 and IN was placed in a cylindrical container with an inner diameter of 8.2 c++, and the above sample was added to the container and the container was covered with a lid. The container was repeatedly inverted (2 seconds per cycle), and the number of reciprocations until the first and second fibers were uniformly dispersed was measured.

In the table below, ○ indicates that the number of times until dispersion was 10 or less, and X indicates that the number of times until dispersion was 10 Table 1 (Note) PET is polyester Example 2 This example is for sanitary use. This indicates that the degree of substitution of carboxymethyl groups in the first fibers constituting the sheet must be 0.25 to 0.4.

The first TA fiber is a carboxyrayon fiber with a fineness of 1 d and a fiber length of 44 m5, and the second fiber is a polyester-polyethylene composite fiber with a fineness of 1.5 d and a fiber length of 44 mm, and a fineness of 1.5 d. Fiber length 4
A web is formed by mixing 4m5 of polyester U and fibers, and this is treated at a temperature of 140'C to give a basis weight of 25g/ff1.
I got 2 sheets.

The wet strength and dispersibility in an alkaline aqueous solution of the obtained sheet were measured in the same manner as in Example 1.

Table 2 (Effects of the Invention) According to the sanitary sheet of the present invention, the sheet contains 30% by weight of fibers that are soluble in an alkaline solution and are carboxymethyl cellulose with a degree of substitution of carboxymethyl groups of 0.25 to 0.4. With the above structure, the water can be dumped into the flush toilet together with the alkaline solution, dissolved and flowed down. In addition, 70% by weight of other fibers that are insoluble in the alkaline solution may be mixed, but even in this case, the fibers are dissolved in the alkaline solution, and as a result, the other fibers are dispersed, The toilet bowl's drain pipe will not be clogged.

Claims (1)

[Claims] A sanitary sheet comprising 30% by weight or more of carboxymethylcellulose fibers having a degree of substitution of carboxymethyl groups of 0.25 to 0.4 and soluble in an alkaline solution.