JPH0195037A - Auxiliary material for sanitary sheet - Google Patents

Abstract

PURPOSE:To provide an auxiliary material for sanitary sheet which has functions for enhancing water-absorbing speed and water-retention (water- retaining power) under pressure, and is reusable and washable by a method wherein voids in fibers composing a fiber layer on the surface side are made greater than those on the rear side thereof for combined use with a highly water-absorptive sheet material. CONSTITUTION:A sanitary sheet auxiliary material is a two-layer structural fiber sheetlike material comprising a surface layer and a rear layer of different void ratio from each other, the void in fibers constituting the surface layer is greater than the void in fibers constituting the rear layer. Since the void in fibers in the surface layer is greater than that of the rear layer, capillarity occurs, water is rapidly absorbed and dispersed in one direction from the surface layer to the rear layer, then absorbed and retained in a highly water-absorptive sheetlike material in contact with the rear layer. As such fiber sheet, at least one selected from knitted fabric and unwoven cloth is preferable, and monofilament degree of the fiber for the rear layer is at least 1 denier or below, and that for the surface layer is at least 1.5 times that of the rear layer.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an auxiliary material for sanitary sheets, and particularly to a sanitary sheet that has excellent water absorption and diffusion power in the negative direction and is used in combination with a super absorbent sheet material. The present invention relates to an auxiliary material for sanitary sheets that has excellent functions of providing a smooth surface and high water absorption rate and water retention ability.

(Prior Art) Conventionally, as sanitary sheets, it has been known to use hydrophilically treated natural fibers such as cotton linen, synthetic fibers, woven fabrics, webs, or nonwoven fabrics, either singly or in a stack of these.

On the other hand, sanitary sheets are also known in which a polymer absorbent material is added to the above-mentioned knitted fabrics, webs, nonwoven fabrics, etc. in order to improve water retention.

(Problems to be Solved by the Invention) However, these have drawbacks such as an insufficient water absorption rate and a lack of a smooth feeling because a large amount of water is retained in areas close to the skin.

The purpose of the present invention is to solve the problems of the prior art, and in particular to increase the water absorption rate and water retention amount under pressure (hereinafter referred to as water retention capacity) by using it in combination with a highly water absorbent sheet material. It is an object of the present invention to provide an auxiliary material for sanitary sheets that has functions, is reusable, and has washing resistance.

(Means for Solving the Problems) The auxiliary material for sanitary sheets of the present invention is a two-layered fiber sheet-like material consisting of a surface layer and a back layer with different porosity,
It is characterized in that the voids between the fibers constituting the surface layer are larger than the voids in the back layer.

The porosity here is expressed as [(fiber density - apparent density)/1a fiber density] x 100. ′ where the apparent density is the weight of each sheet layer divided by its volume.

Because the voids between the fibers are larger in the surface layer than in the back layer, a capillary phenomenon occurs, and water is quickly absorbed and diffused in one direction from the surface layer to the back layer, and is brought into contact with the back layer. Water is absorbed and retained by the super absorbent sheet material.

Here, the fiber sheet is preferably made of at least one selected from knitted fabrics and non-woven fabrics, and the fibers forming the back layer have a single filament fineness of at least 1 denier, and the fibers forming the surface layer The single yarn fineness of the back layer is 1
．． It is preferable that it is 5 times or more.

The back layer sheet material preferably constructed using ultrafine synthetic m-fibers having a single filament fineness of 1 denier or less is not particularly limited in its production method, but for example, a known method for obtaining ultrafine fibers can be used. After spinning seabird-type composite synthetic fibers, exfoliation-type composite wA fibers, etc., and laminating the fibers into filaments or staples to a desired thickness,
Furthermore, needle punching etc. are performed to make a felt-like object,
After that, there are felt-like products obtained by ultra-fine treatment such as sea-removal treatment, and sheet-like products obtained by laminating fiber bundles directly spun as ultra-fine m-fibers and intertwining them by water jet punching, etc. Preferably used. By employing such a manufacturing method, the back layer sheet material becomes a felt-like aggregate composed of fiber bundles that are aggregates of ultrafine fibers, and can sufficiently exhibit the capillary phenomenon described above. As the above-mentioned ultrafine synthetic fibers, polyester fibers, polyamide fibers, polyacrylonitrile fibers, polyvinyl fibers, etc. can be used as appropriate.

It should be noted that the above-mentioned back layer sheet does not necessarily need to be composed of 100% of the ultra-fine synthetic m fibers, and other fibers may be used for reinforcement, cost reduction, etc. within a range that does not impair the effects of the present invention. There is no problem even if they are used in combination, and according to the findings of the present inventors, generally in the back layer sheet-like material,
It is preferable that the ultrafine synthetic fibers be contained within a range of 50 to 100% by weight.

The structure of the surface layer sheet material made of fibers having a single fiber thickness larger than that of the back layer is not particularly limited, and the composition wAn is also synthetic! 100% a fiber
It may be made of 100% chemical fiber, or 100% natural fiber, or it may be made of a blend of these yarns, or a mixture or knitting of these. Further, it may be made using long fibers, short fibers, or a mixture of these.

The means for laminating the back layer and surface layer sheet-like materials may be sewing means such as simply stacking them and quilting sewing them, adhesive means such as point gluing with an appropriate adhesive, fastening means such as hooks or buttons, etc. as appropriate. Can be adopted. Further, it is also possible to employ methods of joining using a binding thread, water jet punching, needle punching, etc. to prevent intertwining.

In the two-layered fiber sheet of the present invention, it is preferable to impart hydrophilicity to the fiber surface by post-modification processing to increase the -layer water absorption rate.

Examples of means for modification include a method of adding a hydrophilic monomer by grafting, a method of adding a hydrophilic group by low-temperature plasma treatment, or coating the polymer with a hydrophilic agent.

The auxiliary material for sanitary sheets of the present invention is made of a superabsorbent sheet-like material from the surface layer (skin side) to the back layer (super absorbent sheet material) by the capillary action of water based on the difference in the size of the voids between the fibers of the surface layer and the back layer. It exhibits the effect of rapidly moving water in one direction towards the surface (contact).

The sanitary sheet auxiliary material of the present invention is preferably used as a diffusion layer inside a normal sanitary sheet material due to the above-mentioned effects.
It increases the water absorption rate of sanitary sheet materials, and also improves the smooth feeling of the surface and the water retention ability of the water retention layer.

(Example) The present invention will be explained in further detail by the following example. The evaluation methods for water absorption rate and water retention capacity in Examples are as follows.

■ A test piece (auxiliary material) with a water absorption rate of 100 c/ is placed on a water retaining sheet, and a triangular funnel (inner diameter 8 mm, foot length 2 cm) is placed above the center of the test piece at a position where the tip of the foot lightly touches the test piece. Cut the sample vertically with the tube, fix the inner diameter of the leg (6 wan), pour 15 mj of distilled water at once from the funnel, measure the time (seconds) required for the distilled water to run out, and measure the average value of the 5 specimens. I took it.

■ Water retention amount 2 A test piece of Q Ocd (auxiliary material + water retention sheet) is immersed in distilled water, and when squeezed with a 400g/cd pressure roller, the amount of pick-up is measured and divided by the area of the test piece. evaluated.

■ Place a test piece (auxiliary material + water retaining sheet) with a water reversion index i o Oej on a waterproof sheet, and place a
Pour +mj of distilled water, leave it for 1 minute, and then add 50 g of water-absorbent sheet (Super Water Absorbent Polymer "Aqua Keep" made by Seitetsu Kagaku ■).
300 g/n1'' of flocculent pulp evenly dispersed and sandwiched between moisture-resistant water-absorbing paper and a waterproof sheet) were layered, and 10
After applying a load of 0 g/cIr for 3 minutes, the weight increase of the water-absorbing sheet is measured, and the value is divided by the area of the test piece. The smaller this value, the higher the water retention capacity, which is an important requirement for sanitary sheets.

(Preparation of water retaining sheet) Poly 1,4-butylene terephthalate was produced from polyester, dimethyl terephthalate, and 1,4-butanediol by a conventional method, and this was pelletized using an extruder. After vacuum drying the pellets, using a melt blow method, using fibers with an average fineness of 0.1 d,
Spun and collected to have a basis weight of about 400g/rIt'',
A fibrous web was obtained.

Furthermore, cotton gauze was laminated on the front and back sides of this web, and quilting was performed to obtain a sheet-like product.

Terephthalic acid, ethylene glycol,
Block copolymer of polyethylene glycol (terephthalate unit/polyethylene glycol unit = 3.O
/ 7.0 weight ratio, molecular weight of polyethylene glycol 1
10% by weight of a 10% aqueous dispersion (hydrophilic agent) of
A treatment bath with a bath ratio of 1:30 was prepared using the following methods, and the object to be treated was immersed in this bath, heated in the bath at 130° C. for 40 minutes, and dried to obtain a water-retaining sheet.

(Example) Composite fibers (single fiber fineness 36 denier) with a seabird ratio of 50:50 were spun to make staples with a length of 511II11. The composition of this composite fiber is such that the number of islands is 1.8, and the polyester fiber has a fiber fineness of 0.01 denier after sea removal.

A web was made using a roller card using such staples, and 15 layers of this were superimposed to give a fabric weight of 500 g.
/rn'' felt was produced. This felt was subjected to sea removal treatment of the composite fiber using a sea component solvent (triclene) to form a back layer sheet-like material made of polyester fiber with a single fiber fineness of 0.1 denier. I got it.

A block copolymer of terephthalic acid, ethylene glycol, and polyethylene glycol (terephthalate unit/polyethylene glycol unit = 3°O/7.0 weight ratio, molecular weight of polyethylene glycol 1
A treatment bath with a bath ratio of 1:30 was prepared using 10% by weight of a 10% aqueous dispersion of 000), and the object to be treated was immersed in this bath, heated in the bath at 130° C. for 40 minutes, and dried.

In addition, 15% of polyester false-twisted modified yarn
A knitted fabric (surface layer) was made using 0 denier-30 filament yarn, and subjected to almost the same hydrophilic treatment as above.

A sanitary sheet auxiliary material was obtained by laminating the front layer and the back layer by quilting sewing. The water absorption speed of this auxiliary material for sanitary sheets was 6.5 seconds. Next, this auxiliary material for sanitary sheets was laminated on the water retaining sheet with the back layer facing down, and its water absorption properties were investigated. The results are shown in Table 1.

Table 1> Even with water-retaining sheets that have a slow water absorption rate and poor water-holding ability, by using this auxiliary material for sanitary sheets in combination, excellent water-absorbing properties that could not be achieved with conventional water-retaining materials for sanitary sheets were obtained.

Claims (4)

[Claims] (1) A auxiliary for sanitary sheets, which is a two-layered fiber sheet-like material consisting of a surface layer and a back layer, characterized in that the voids between the fibers constituting the fiber layer are larger on the front surface than on the back surface. Material. (2) The auxiliary material for sanitary sheets according to claim (1), wherein the fiber sheet is at least one type selected from knitted fabrics and nonwoven fabrics. (3) The sanitary sheet according to claim (1), in which the fibers constituting the back layer have at least a single denier fineness of 1 denier or less, and the fibers constituting the surface layer are at least 1.5 times thicker than that. Auxiliary material. (4) The auxiliary material for sanitary sheets according to claim (1), wherein the two-layered fiber sheet has a water absorption rate of 10 seconds or less.