JPH0197255A - Sanitary sheet auxiliary material - Google Patents

Abstract

PURPOSE: To obtain an auxiliary material for a sanitary sheet high in water holding quantity and water-holding capacity, excellent in resistance to washing, suitable for diapers, underwears or the like by laminating a specific fabric on one surface of a water retaining sheet and using the back side as the water retaining sheet. CONSTITUTION: This auxiliary material has at least one a fabric base that is formed of plural fiber threads and has a structure in which the surface and the back are connected with connecting threads and the threads constituting the surface is larger in denier than that of the threads constituting the back. Its back face is laminated with a water retaining sheet. The single yarn denier of the thread constituting the fabric is 1.0 to 2.5 denier, and the single yarn denier of the thread constituting the surface is 1.5 to 5.5 times that of the thread constituting the back face. The water retaining sheet is a nonwoven fabric obtained by confounding a hydrophilic synthetic ultrafine fiber having single yarn denier of <=1, and preferably has a compact layer having lower porosity than that of the inner side on both the surface and the back face.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Applications!) The present invention relates to a sanitary sheet auxiliary material that has a high water absorption rate and excellent water retention and water retention ability.

(Prior Art) Conventionally, sanitary sheets have been made of natural fibers such as cotton linen and synthetic J! I-fiber fabrics, webs, non-densified fabrics, etc. that have been subjected to hydrophilic treatment are known to be used alone or in a stacked manner.

On the other hand, sanitary sheets are also known in which a polymer absorbent is added to the above-mentioned MRA material, web, non-densified fabric, etc. in order to improve the water retention ability.

(Problems to be solved by the invention) However, although these have the disadvantage that the water absorption rate is not sufficient and the water retention capacity in the absence of pressure (hereinafter referred to as water retention capacity), the water retention capacity under pressure (hereinafter referred to as water retention capacity) is low. (called holding force)
There are drawbacks such as the fact that the polymer absorbent sheet is small and tends to bounce back, and polymer absorbent sheets used in disposable diapers and the like have the drawback that the polymer absorbs water and hardens, making it impossible to reuse.

The purpose of the present invention is to solve the problems of the prior art, and in particular to provide a sanitary sheet auxiliary material that has a high water absorption rate, excellent water retention and water retention ability, is reusable, and has washing resistance. It is about providing.

(Means for Solving the Problems) The sanitary sheet auxiliary material of the present invention is a fabric made of a plurality of fiber threads on at least one side of a water-retaining sheet, the front and back sides of which are bound by a binding thread. It is made by laminating fabrics in which the yarns constituting the front surface have a larger single filament fineness than the yarns constituting the back surface, with the back surface facing the water-retaining sheet side.

In the sanitary sheet auxiliary material of the present invention, the fabric laminated on at least one side of the water-retaining sheet is a fabric constructed using a plurality of fiber threads as described above, and the front and back surfaces thereof are made of bound threads. The essential feature is that the yarns constituting the front surface have a larger single yarn fineness than the yarns constituting the back surface. Here, the fabric is preferably M woven fabric, and the single yarn fineness of the yarn forming the back side is 1.0 to 25 deniers, and the single yarn fineness of the yarn forming the front side is 1.0 to 25 deniers.
Preferably, it is 5 to 5.5 times larger. In addition, the structure in which the front surface and the back surface are bound by a binding thread may include a structure using a thread prepared as a binding thread separate from the threads constituting the front surface and the back surface, or a structure using a thread prepared as a binding thread separate from the threads constituting the front and back surfaces, or There are structures in which the threads forming the surface are also used as binding threads.

For example, in the case of a knitted fabric, a two-sided weft fabric of a two-sided nine-knitted fabric where the front fabric and the back fabric are bound with binding threads forming a double-sided tuck knit, and one side is formed while the other side is tuck knitted. These include double-sided nine knitted fabrics and double-sided flat knitted fabrics that form a knot, and warp knitted fabrics include double raschel and double tricot.

On the other hand, in the case of woven fabrics, the front and back fabrics are bound together with a single bound thread, such as those obtained on a double velvet loom, or either warp or weft yarns forming one side. Warp and weft double woven fabrics in which the threads of the two sides are connected to the other side by connecting points, or weft yarns that form one side (warp yarns) and weft yarns that form the other side (warp type). These include horizontal double-layered fabrics (warp double-layered fabrics) that are joined by connecting points of threads (weft threads).

In particular, it is preferable to use threads constituting the surface as joining threads.

The fiber yarns constituting such a fabric are particularly preferably hydrophobic fiber yarns. Specific examples of hydrophobic fiber threads include synthetic fibers such as polyester, polyamide, polyacrylonitrile, and polypropylene. Further, in order to increase the initial water absorption rate, it is preferable to impart hydrophilicity to the surface of the hydrophobic fiber by processing after modification.

In the present invention, the fabric having the above-mentioned structure is laminated on a water-retaining sheet with the back side facing the water-retaining sheet. By adopting such a laminated structure, a remarkable capillary effect is produced, and water from the surface (skin surface) is removed. It quickly diffuses to the back surface, retains water in the water-retaining sheet layer, and exhibits the effect that the retained moisture is difficult to return even under pressure.

As the water-retaining sheet constituting the sanitary sheet auxiliary material of the present invention, an appropriate water-retaining sheet such as a hydrophilic non-densified fabric is used to synergistically express the effects of the fabric layer described above and also improve reusability. As a water-retaining sheet, it is possible to use a non-densified fabric made by intertwining hydrophilic ultrafine synthetic fibers with a single filament fineness of 1 denier or less, which has a dense layer with a lower porosity than the inside on the front and back sides. preferable. By using ultrafine fibers with a single filament fineness of 1 denier or less, the surface area of wAn is large, so the effective contact area with water is large, and the water retention capacity is excellent, and the water absorption rate is fast (1 denier) due to capillary action. If it is larger, the surface area of the fiber becomes smaller and the effective contact area with water becomes smaller, making it impossible to exhibit sufficient water retention ability, and the water absorption rate due to capillary action is also lowered.

Such ultrafine fibers and non-densified fabrics are usually obtained by entangling a web obtained by melt blowing with a water jet punch, or by forming a seabird-shaped polymer mutual array mu stable into a web with a cross wrapper and then water jet punching. It is produced by a method such as entangling with chlorine and removing it with treclene or the like.

Although a dense layer with a lower porosity than the inside is formed on the front and back surfaces of the non-densified fabric by interlacing it with a water jet punch, there is little yarn breakage and the texture is soft. .

This characteristic is unique to water jet punches and does not occur with needle punches.

In other words, with a needle punch, the needle penetrates the non-densified fabric, so the punching force on the surface and inside is fairly constant, but with a water jet punch, the water pressure is extremely small on the inside compared to the surface, so the surface It is mixed with honey.

The difference in porosity between the front and back layers is 4% or more, especially 7%
It is preferable that it is above because it shows more excellent water retention capacity.

The average porosity of the front and back surfaces is 50-85%, especially 60-83%
Those within the range of water retention are preferably selected.

The porosity here is expressed as [(fiber density - apparent density)/m fiber density] x 100.

In the formula, the apparent density is the value obtained by dividing the weight of the non-densified fabric by the volume of the non-densified fabric.

In addition, this water-retaining sheet has a normal water reversion index of 1.0X.
10-2g/art or less, preferably 0.5X10
g/cd or less.

The water reversion index referred to here means that a 100 d test piece is placed on a waterproof sheet, and a beaker is placed in the center of the test piece.
Pour 51111 distilled water, leave it for 1 minute, and then remove the water absorbent sheet (
Super water-absorbing polymer “Aqua Keep” manufactured by Seitetsu Kagaku ■ 5
300 g of flocculent pulp evenly distributed at 0g/rr1″
/ m sandwiched between moisture-resistant water-absorbing paper and a waterproof sheet), and after applying a load of 100 g/c+/ for 3 minutes,
This is the value obtained by measuring the weight increase of the water-absorbing sheet and dividing it by the area of the test piece.

The hydrophilic ultrafine synthetic fibers constituting the water-retaining sheet may be hydrophilic fibers that are hydrophilic from inside the Iam, such as hydrophilic monomer copolymerized polyester, or hydrophobic fibers such as polyamide, polyester, and polyolefin. It may also be one in which hydrophilicity is imparted to the fiber surface by processing after modification of the W4 fiber.

Examples of polyesters copolymerized with wood-philic monomers include polyesters having sulfonic acid groups and/or their alkali metals in the acid component.

Examples of modification methods 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.

Such a water-retaining sheet has excellent water-retaining ability due to its hydrophilicity and large porosity, and also exhibits a capillary effect, which increases the water absorption rate and water retention ability and reduces back-retention. can synergistically enhance the effects of The water-retaining sheet and the fabric layer are laminated as appropriate by point adhesion using an adhesive, sewing, etc. depending on the particular use of the sanitary sheet.

Although the auxiliary material of the present invention can be used by itself as a sanitary sheet, it is generally used in combination with a hydrophobic net, a moisture-permeable waterproof cloth, etc. to form a sanitary sheet.

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

■ Place a test piece with a water absorption rate of 100 cJI on a waterproof sheet, and place a triangular funnel (inner diameter 8 cm, foot length 2 cJI vertically cut, foot Fix the funnel (inner diameter 6 cm) and pour 15 m of distilled water from the funnel.
Pour Z all at once and find out how long it took for the distilled water to run out (
seconds) was measured on five test pieces, and the average value was taken.

■ A test piece (laminated cloth) with a water retention capacity of 200cj was immersed in distilled water,
The amount of pick-up when squeezed with a pressure roller of 0 g/d was measured and evaluated by dividing the value by the area of the test piece.

EXAMPLES AND COMPARATIVE EXAMPLES Poly 1,4-butylene terephthalate was produced from polyester, dimethyl terephthalate, and 1,4-butanediol by a conventional method, and pelletized using an extruder. After vacuum drying the pellets, using a melt blow method, using fibers with an average fineness of 0.1 d,
The fibers were spun and collected to obtain a fiber web having a basis weight of approximately 400 g/rn''.

Furthermore, cotton gauze is laminated on the front and back sides of this web, and the water pressure is 50.
The web was entangled with a water jet punch of kg/cd to obtain a non-densified fabric.

A block copolymer of terephthalic acid, ethylene glycol, and polyethylene glycol (terephthalate units/polyethylene glycol units = 3. O/
7.0 weight ratio, molecular weight of polyethylene glycol 100
A treatment bath with a bath ratio of 1:30 was prepared using 10% by weight of the 10% aqueous dispersion (hydrophilizing agent) of 0), the object to be treated was immersed in this bath, and heated in the bath at 130°C for 40 minutes. It was treated and dried to obtain a water retaining sheet.

On the other hand, using a double-sided circular knitting machine 22G and using polyester yarns 1 and 2 shown in Table 1, a double-sided knitted fabric was made into a rope by forming the front side with yarn 2 and joining the back side formed with yarn 1 by tuck knitting. did. The obtained gray cloth was finished by scouring and dry heat setting according to the usual dyeing processing conditions. Also,
A portion of the water-retaining sheet was treated in the same manner as the hydrophilic treatment.

The water absorption properties of this knitted fabric laminated on the water-retaining sheet and the water-retaining sheet alone were investigated. The results are shown in Table 1.

One with a single yarn fineness ratio of 1.00 (Comparative Example 1), and one with a thick yarn 1 forming the back side (m degree 2.78 d).

In Comparative Example 2), the water absorption rate was slow and sufficient water absorption performance could not be obtained.

Water absorption speed (5 seconds or less), reverse recovery index (1.0 or less),
Particularly preferred is one that satisfies all water retention requirements (O12 or higher).

(Effects of the Invention) The sanitary sheet auxiliary material of the present invention has a high water absorption rate, a large amount of water retention, a high water retention capacity, and excellent washing resistance, and can be used in a wide range of applications.

Applications that utilize these characteristics include, for example, shorts for incontinence, diapers, training pants for infants, sanitary napkins, underpants for sports, towel materials,
Examples include underwear, wet towels, dish towels, sheets, pillowcases, and paper towels.

Claims (3)

[Claims] 1. At least one side of the water-retaining sheet is a fabric consisting of a plurality of fiber threads, the front and back sides of which are bound together with binding threads, and the number of threads forming the front surface is smaller than that of the threads forming the back side. A sanitary sheet auxiliary material made by laminating fabrics with high yarn fineness with the back side facing the water-retaining sheet. 2. The single yarn fineness of the yarn constituting the back side of the fabric is 1.0.
~2.5 denier, and the single yarn fineness of the yarn constituting the front surface is 1.5 to 5.5 times the single yarn fineness of the yarn constituting the back surface. Seat auxiliary material. 3. The water-retaining sheet is a non-densified fabric made by intertwining hydrophilic ultrafine synthetic fibers with a single filament fineness of 1 denier or less, and has a dense layer on the front and back surfaces with a lower porosity than the inside. The sanitary rate auxiliary material described in item 1.