JPH01192802A - Disposable sanitary material - Google Patents

Abstract

PURPOSE:To obtain a disposable sanitary material having satisfiable strength and liquid-permeability and excellent skin feeling and wet-returning resistance, by using a particular nonwoven fabric as a skin-containing liquid-permeable surface sheet of the sanitary material. CONSTITUTION:A disposable sanitary material such as paper diaper or sanitary napkin has a liquid-permeable surface sheet contacting with the skin of the wearing person. The surface sheet is composed of a nonwoven fabric produced by using a web of continuous filaments of crimped crystalline thermoplastic fiber having modified cross-section and bonding the web by partial thermocompression bonding. The crystalline thermoplastic fiber is preferably polypropylene fiber or polypropylene-polyethylene composite fiber. The partial thermocompression bonding is preferably carried out by embossing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to disposable sanitary materials, particularly sanitary materials such as disposable diapers, sanitary napkins, and puerperal napkins.

More specifically, the present invention relates to a disposable sanitary material having a surface sheet made of a nonwoven fabric that has a good texture and reduces wetness of drained liquid during practical use.

[Prior art and problems to be solved by the invention] Conventional disposable sanitary materials, such as disposable diapers and sanitary napkins,
It has a structure in which an absorbent material made of cotton-like pulp, absorbent paper, super absorbent resin, etc. is sandwiched between a liquid-permeable sheet on the side that contacts the skin and a liquid-impermeable sheet on the back side, and the liquid is drained. The liquid passes through a liquid-permeable sheet (hereinafter referred to as the top sheet) and is absorbed and retained by the absorber, and the liquid-impermeable sheet on the back prevents the liquid from leaking to the outside. A nonwoven fabric is generally used for this top sheet.

The nonwoven fabric used as such a top sheet is required to have various performances, but the important ones are that it has excellent texture (feel and softness), especially since it comes into direct contact with the skin, and From a practical and sanitary standpoint, the rate of permeation of liquid into the absorber is high, and the absorbed liquid does not rewet easily.

In addition, it is necessary to meet the practical strength required for sanitary materials during use, and it is also necessary to reduce dimensional changes caused by tension applied to nonwoven fabrics during the process that has occurred with the increase in the production speed of sanitary materials in recent years, such as width. Performance that can withstand shrinkage is required.

Various nonwoven fabrics have been researched to meet the above requirements and have been proposed.

For example, spunbond nonwoven fabrics made of hydrophobic fibers such as polypropylene are widely used as top sheets for sanitary materials. This nonwoven fabric is strong, so it is difficult to break during use, and has excellent dimensional stability during the production of sanitary materials, so it has a relatively low basis weight, e.g.
5 g/n (~25 g/n) can be used as a nonwoven fabric. However, since the fiber arrangement in this nonwoven fabric is planar, the bulkiness is poor, and the feel and softness are insufficient. .

Also known is a nonwoven fabric in which short hydrophobic fibers are made into a web using a card and the fibers are joined by partial thermocompression bonding. This non-woven fabric can give a sense of thickness and softness by crimping the fibers used, but on the other hand, the strength of the non-woven fabric is insufficient during use and during the manufacturing process, and in order to compensate for this, a relatively large basis weight is used. Non-woven fabric, e.g. 20g/bo~35
g/n (used as a nonwoven fabric).

Furthermore, a nonwoven fabric is known in which a stable latent crimped fiber, such as a bicomponent composite fiber, is formed into a web and then heat-treated in an oven to develop crimps and bond the fibers. This non-woven fabric has more sufficient crimp than the above-mentioned non-woven fabric made by partial thermocompression bonding using short fibers, so it has a better thickness and softer feel, but it does not have the problem of insufficient strength in use and manufacturing. Therefore, in order to compensate for these problems, it is necessary to use a nonwoven fabric with a high basis weight.

In addition, the rebound property is generally improved by using hydrophobic fibers and increasing the thickness of the nonwoven fabric. However, the wettability under load when using sanitary materials, such as under the weight of an infant in a disposable diaper, varies depending on the type of nonwoven fabric used. No nonwoven fabric has yet appeared that has sufficient wettability even in terms of basis weight during use.

The present invention solves the problems of topsheets in conventionally known disposable sanitary materials, and has sufficient performance in terms of strength, dimensional stability, and permeability to withstand use, and is particularly excellent in texture and wettability. The purpose is to provide a disposable sanitary material comprising a non-woven fabric.

[Means to solve the problem]

The above-mentioned object of the present invention is a disposable sanitary material comprising a top sheet that is permeable to liquid discharged from a human body, a liquid-impermeable back sheet, and an absorbent body located between the front and back sheets. , wherein the top sheet is a nonwoven fabric in which a continuous filament calar web of crystalline thermoplastic fibers having irregular cross sections and crimps is bonded by partial thermocompression bonding, which is uniformly applied over the entire surface of the web. Solved by disposable sanitary materials.

The present invention will be described in detail below with reference to the accompanying drawings showing an example of the disposable sanitary material and nonwoven fabric of the present invention. Figure 4 shows a plan view of an example of a disposable diaper, which is a type of disposable sanitary material of the present invention.・Figure 5 shows its cross-sectional view. Fourth
As shown in the figure and FIG. 5, the disposable diaper I has a top sheet (tomp sheet) 2 on the front side, a liquid-impermeable back sheet (bank sheet) 4 on the back side, and is arranged between the top sheet 2 and the back sheet 4. The disposable diaper 1 is made of an absorbent body 3, and has serrations 5 on both sides, and tape fasteners 6 on both upper sides. When in use, the top sheet 2 is placed on the human body side, and the liquid discharged from the human body passes through the top sheet 2 and is absorbed and retained in the absorbent body 3, and the liquid impermeable back sheet 4 prevents the liquid from leaking to the outside. Prevented. Since the structure of such a disposable diaper itself is well known, description of each component other than the topsheet 2 will be omitted below.

As mentioned above, the top sheet used in the disposable sanitary material of the present invention is made by partially thermocompressing a web made of continuous filaments of crystalline thermoplastic fibers having an irregular cross section and crimps, uniformly applied over the entire surface of the web. As will be explained in detail in the examples below, this nonwoven fabric has sufficient strength, dimensional stability, and permeability to withstand use, and has particularly good texture and wettability. Excellent in

First, the excellent wettability of the nonwoven fabric used in the disposable diaper of the present invention (hereinafter referred to as the nonwoven fabric of the present invention) will be explained. Figure 1 shows the wettability (measurement method will be described later) and load (
g/4all). Curve a in FIG. 1 is the rewetting amount vs. load curve of a nonwoven fabric with a basis weight of 20 g/n (corresponding to Example 1 described below) of the nonwoven fabric of the present invention; This is a curve of rewetting amount versus load of a bonded nonwoven fabric (basis weight 20 g/ITr), and curve C is a short fiber of polypropylene/polyethylene composite fiber (3d x
51 m) of a bulky nonwoven fabric (fabric weight 23 g/nf).

In general, the load applied to a disposable diaper when an infant sits down is said to be 3.6 kg / 10 cm x 10 ohms, and when converted to the value on the horizontal axis in Figure 1, this value is 1.
It becomes 44g/4cIA. Therefore, FIG. 1 shows the wettability of the nonwoven fabric against loads including the load applied to the disposable diaper by an infant.

As is clear from FIG. 1, the amount of rewetting increases as the load increases, and in particular, in the conventional nonwoven fabrics shown by curves a and 1, the amount of rewetting increases rapidly as the load increases. The practical limit for the amount of wetness is 0.10
Considering that it is said that the wettability of conventional nonwoven fabrics is 100 g, it cannot be said that the amount of rewetting of conventional nonwoven fabrics is sufficient under high loads. On the other hand, the nonwoven fabric of the present invention has the advantage that the amount of rewetting is not only lower than the limit value of 0.10 g, but also that the degree of increase in the amount of rewetting with increasing load is low.

Corresponding to FIG. 1, FIG. 2 shows a graph of thickness change with respect to compressive load of the nonwoven fabric. Curves a and b.

The nonwoven fabric designated by C corresponds to the nonwoven fabric shown by curves a, b, and c in FIG. The conventional spunbond nonwoven fabric shown by the curve has a small amount of compression change due to load, and the absolute value of the thickness under high load is low. This seems to be the reason why conventional spunbond nonwoven fabrics are inferior in flexibility and rewetting properties. The conventional bulky short fiber nonwoven fabric shown by curve C has a large thickness at zero load, but as the load increases, the thickness continues to decrease rapidly. From this, it can be inferred that conventional bulky short fiber nonwoven fabrics have softness, but their wettability deteriorates as a load is applied. On the other hand, in the nonwoven fabric of the present invention shown by curve a, the thickness at zero load is lower than that of the bulky short fiber nonwoven fabric, but as the load increases, the thickness rapidly decreases to 20
The thickness gradually decreases from the point where the thickness exceeds g/4aJ. From this, it can be inferred that the nonwoven fabric of the present invention has both softness and excellent wettability.

As is clear from the above description, the softness (a characteristic of texture) and wettability that are particularly required for a topsheet can be approximately understood by the curve of compressive load versus thickness.

FIG. 3 shows compressive load vs. thickness curves for three types of nonwoven fabrics obtained from the nonwoven fabric of Example 1 (fabric weight 20 g/n?) with only the fabric weight changed and other conditions being the same as in Example 1. curve d
, e, f have a basis weight of 15 g/rrl and 18 g/n, respectively.
, 25 g/rd.As is clear from FIG. 3, as the basis weight increases, the thickness for each load naturally increases, but the tendency of the curve is the same for each nonwoven fabric.

The nonwoven fabric of the present invention consists of continuous filaments of crystalline thermoplastic fibers having irregular cross-sections and crimps. The crystalline thermoplastic fibers mentioned here include polypropylene fibers,
Polyethylene fibers, polyester fibers, etc. can be used, but it is more preferable to use polypropylene fibers, which are hydrophobic and easily give the spiral crimp described below.

Although various cross-sectional shapes can be used as the irregular cross-section, it is preferable that the irregular cross-section is a polygonal cross-section having three or more convex portions outside the center, as illustrated in FIG. In this case, as shown in FIG. 6, when the width of the bottom of the convex portion is t, the length of the convex portion is β, and the cross-sectional area of the fiber is S, most of the constituent filaments satisfy the following conditions. It is preferable to have a cross-sectional shape.

l ≧ t The crimp imparted to the filament is preferably a helical crimp, and the helical diameter is preferably 11 or less, and it is further preferred that the filament is arranged in a three-dimensional manner while being twisted in the nonwoven fabric. The crimp helix diameter is 1.0 to 0.3.
It is more preferable that it is m.

If the crimped helix diameter exceeds Q mu, the number of crimps per unit length will be small, resulting in poor bulkiness and 0.3 v
If it is less than nx, the space obtained by the spiral shape becomes extremely small, resulting in poor bulkiness, and the entanglement between filaments becomes too strong, which tends to cause myositis during web production.

It is preferable that the filaments in the nonwoven fabric have one or more twists within the length 15n+ of the filaments.

The mechanism by which the filaments constituting the nonwoven fabric of the present invention are twisted will be explained based on FIG. In producing the nonwoven fabric of the present invention, in addition to the first cooling device for cooling the asymmetrically spun filaments as described below, a second cooling device is used to give twist to the filaments. The state of the filament at this time is shown in FIG. 7A. In other words, the upstream vertices a, b, and c of the triangular cross section are a', b' at the downstream.
.

It is twisted as shown by C'. In this twisted state, cooling air is applied from the first cooling device, so that the cooling air side, that is, the front side in FIG. 7A, is cooled and solidified first to form a low-density portion. In the filament that has been spun and taken off, as shown in FIG. 7B, each of the upstream vertices a and b of the triangular cross section.

C and the downstream vertices ar, br, c, and r return to corresponding positions, and the low-density portions are twisted and arranged relative to this.

Therefore, as illustrated in FIG. 8, in the filament constituting the nonwoven fabric of the present invention, one component (shaded area) is exposed and hidden four times for every 2.5 crimp times in the figure.

On the other hand, as shown in FIG. 9, in the conventionally known spiral crimp of untwisted filaments in long fiber nonwoven fabrics, the number of times of helical crimp is the same as the number of times one component is hidden. That is, one component, such as a low-density section, arranged on the outside of the helical shape is always on the outside in the longitudinal direction of the filament.

Various finenesses of filaments constituting the nonwoven fabric of the present invention can be used. However, in order to use it as a thin Tomisho nonwoven fabric for the top sheet of disposable diapers,
d~5. Filaments with a fineness of Od are preferably used.

The nonwoven fabric of the present invention has a weight of 15 to 30 g/rr from the viewpoint of required characteristics as a top sheet and economical efficiency. It is preferable to use one with a basis weight of . The nonwoven fabric of the present invention has excellent rewetability, as will be made clearer in the Examples below.
It has the advantage that the desired wettability can be achieved with a nonwoven fabric having a lighter basis weight than conventional nonwoven fabrics.

The more flexible the nonwoven fabric is, the easier it is to stretch in the warp and weft directions. In particular, when a nonwoven fabric that is easy to stretch in the warp direction is used for the top sheet, there is a problem that the nonwoven fabric stretches in the warp direction during the manufacturing process of the disposable diaper, and the width in the weft direction becomes narrower as the nonwoven fabric stretches in the warp direction. In order to solve the above problem, when the nonwoven fabric of the present invention has a fabric weight of 20 g/a,
It is preferable that the % modulus is 0.4 kg/actn width or more.

Before explaining other characteristics of the nonwoven fabric of the present invention, an example of a method for manufacturing the nonwoven fabric of the present invention will first be explained with reference to FIG. 10. The spunbond nonwoven fabric of the present invention is produced by melt-extruding polypropylene through a irregularly shaped die 11, and blowing cooling air from a direction perpendicular to the running direction of the yarn Y under special conditions described below immediately after arriving in Japan. While performing asymmetrical cooling in the cross-sectional direction, the material is taken up by a high-speed towing and taking-off device 14 such as a high-speed (I4) air soaker.

The yarn leaving the high-speed traction device 14 is collected and conveyed as a web 20 on a wire mesh conhair 16 moving past a charging device 15 and is thermally bonded by a partial thermal bonding roll 17 . Subsequently, a liquid permeable agent is applied to the fabric by a liquid permeable treatment device 18, and the spunbond nonwoven fabric 21 is wound up by a winder 19.

In the method for producing a nonwoven fabric of the present invention, the lower part 10 to 15
In addition to the normal cooling air supply device 12 (hereinafter referred to as the first cooling device 12) having its upper end at the centimeter position, a cooling air supply device 12 (hereinafter referred to as the first cooling device 12) is provided with a cooling air supply device 12 located closer to the spinneret surface. 0.5~1.°~45° in different directions. Q m
A cooling air supply device 13 (hereinafter referred to as a second cooling device 13) that discharges cooling air at a speed of 1/sec is arranged. The cooling air mentioned here has a temperature of about 70% RH and 20° C. at the outlet.

The crimped filament of the present invention is produced by using another cooling air at a position closer to the spinneret surface than the normal cooling air and at a different angle from the normal cooling air. As a result, the location where the material is cooled and solidified changes randomly along its length. As a result, the helically crimped filament itself becomes twisted in the longitudinal direction as explained based on FIG.

When manufacturing a filament having a helical crimp, the windward side of the irregularly shaped filament is first cooled and solidified, and then the leeward side is solidified. By doing this while being pulled at a high speed, the threads are released from the high speed pulling and are collected as a web on the collecting surface, resulting in visible crimp.

Although the windward side cools and solidifies, it is elongated by the traction force of high-speed traction, and in this state, the leeward side cools and solidifies.
It is thought that only the windward side, which had been elongated when released from the traction force, contracts, causing overt crimp. When the crimped filament of the present invention is polypropylene, its density is 0.900 or less, but conventional filaments without crimps have a density of more than 0.905, and the part that cools and solidifies first on the windward side has a density of 0.900 or less. The density is considered to be approximately 0.805, with crystallization being extremely suppressed.

The filaments constituting the nonwoven fabric of the present invention thus obtained are as shown in FIG.
It is moved by being placed inside.

Next, partial thermocompression bonding will be explained.

Partial thermocompression bonding is carried out by pressing a engraved roll or flat plate against each other, but the roll method is preferred from a production standpoint. A combination in which one is an engraving roll and the other is a smooth metal roll, or a method in which both the upper and lower engraving rolls are butted together is adopted. The degree of thermocompression bonding is determined by setting the temperature and contact pressure of the upper and lower rolls according to the required performance such as the strength and fluffiness of the resulting nonwoven fabric, but the upper hand temperature must be below the melting point of the fibers used. It is preferable to set it to .

Furthermore, the texture of the finished nonwoven fabric is greatly influenced by the embossed pattern of the engraving, and among these, the thermocompression area ratio, engraving interval, and engraving depth are important points.

FIG. 11 shows each side of the embossed pattern preferably used to produce the nonwoven fabric of the present invention, and Table 1 shows the corresponding dimensions of each embossed pattern. In FIG. 11, t indicates the minimum interval between each embossing.

Margin below (I8) Practical thermocompression bonding area ratio is 2 to 30%. However, from the viewpoint of the texture and fluffiness required for a nonwoven fabric for a topsheet, it is preferable to use an embossed pattern with a thermocompression bonding area ratio of 5% to 15%. Naturally, at a low thermocompression bonding rate, the bulkiness due to crimping is maintained, but no matter how the pattern is chosen, the fluffiness is poor, and at a high thermocompression bonding rate, the quality of the crimped fibers is lost, the texture is hard, and the bulkiness is lost.

The spacing between the embossed carvings depends on the pattern, but if it is 0.3W or more, the effect of the fibers will be more effective than if they are continuous. On the other hand, if the web is over 10m/m, the web can be fixed, but the surface sheet becomes fluffy and weak in terms of strength.
The depth of the emboss engraving is an important factor to take advantage of the bulkiness of the crimped fibers. thickness is affected.

In addition, depending on the basis weight, it is at least 0 to make use of crimped fibers.
．． Must be 3fi or higher, softer,
In terms of bulk, it is preferably 0.5n or more. Taking these points into consideration, it is necessary to select a preferred pattern for the top sheet of sanitary materials.

Fig. 12 shows a microscopic photograph of a cross section of an example of the nonwoven fabric of the present invention including a partial thermocompression bonded part, Fig. 13 shows a diagram explaining the function of the partial thermocompression bonded part in the nonwoven fabric of the present invention, and Fig. 14 shows a fusion bonded part. 1 is a diagram illustrating a joining function in a nonwoven fabric in which single fibers are joined together by fusion using fibers or the like. Figure 13 (
1) and FIG. 14(1) are cross-sectional views of the nonwoven fabric, and FIG. 13(2) and FIG. 14(2) are plan views each showing a model of the bonded state of fibers.

In the nonwoven fabric 2 of the present invention, as shown in FIGS. 12 and 13, a large number of fibers 8 existing on the front and back sides of the web are integrated at the partial thermocompression bonding portion 7, and as a result, a force that deforms the web acts. In this case, for example, a large number of fibers located at the position indicated by 9 in FIG. 13(1) would work together to resist external force, and as a result, it would be difficult to deform. On the other hand, when the constituent fibers 8 are joined at their intersection points 10 as shown in FIG. 14, when an external force is applied, only one or several fibers gather at the joining point. Therefore, it is thought that resistance to external force is weak, and as a result, it becomes easy to deform under compressive load.

In nonwoven fabrics made of crystalline thermoplastic fibers, it is difficult or takes a long time for fluids discharged from the human body to pass through them. Therefore, it is preferable to impart liquid permeability to the nonwoven fabric of the present invention. To impart this liquid permeability, hydrophilizing agents such as various activators may be added to the fibers, or fibrous or
Examples include a method of applying it to the surface in the form of a web or non-woven fabric. From the viewpoint of processing difficulty, processing in the non-woven fabric state is preferred, but it is necessary to avoid bulkiness due to crimp.

As for the processing agent to be used, it is necessary to consider not only liquid permeability and wettability, but also safety to the human body, stability in the process, etc. Nonionic surfactants to which micron oxide has been added, anionic surfactants such as alkyl phosphate salts, alkyl sulfates, etc. can be used alone or in mixtures.

As post-treatment, diluted solutions are usually used by dipping method, coater method,
It is applied by a spraying method and then dried to finish. Depending on the processing agent used and the desired performance, it is added to the fibers in an amount of 0.1 to 1.0%, but it goes without saying that the amount should be set to the minimum necessary since it comes into direct contact with the human body.

〔Example〕

The present invention will be explained in further detail with reference to Examples below.

Prior to the description of Examples, the definitions and measurement methods of physical property values used in the present invention will be summarized below.

◎ Fabric weight: Expressed in weight (g) per 1 d of nonwoven fabric.

◎ Helix diameter: Measure the diameter of the loop under a microscopic photograph of the nonwoven fabric, and use the average value (n).

◎ Width t (μ) of the protrusion in the fiber cross section The width of the protrusion at the root position of the protrusion in the fiber cross section (average value for 10 filaments).

◎ Length of protrusion in fiber cross section l (μ) Average value of 10 filaments as the distance from the root of protrusion to the tip of protrusion in cross section of fiber.

◎ Twisting in the longitudinal direction of the filament In an electron micrograph, the filament is strongly twisted (the angle of twist exceeds 10°) and the part where the twist is reversed. Expressed in crane units.

■ Thickness change due to compressive load Using a compressive elasticity tester model E-2 manufactured by Nakajiro Denki Sangyo ■, under a measurement area of 4 d, the compressive load was 0°10.20, 50,
100. The thickness T (μ) of the nonwoven fabric at each load was measured.

◎ Permeation rate (sec/5 cc) & rewetting amount (g) As an absorber, in order to keep the characteristics of the absorber constant, we used a specific filter paper (“93” manufactured by Baton Dikeman).
9゜10cm square x 3 stacked) with a measuring device (approximately 800g,
(10cm square with a 25mm diameter hole in the center)
Place it at the bottom of the

A test cloth (10 cm square) is placed on top of this absorbent body.

First, 5 cc of artificial urine is dripped from this upper portion. Artificial urine is made by adding a nonionic activator to physiological saline at 25℃.
was adjusted to 45±3 dyne/cm (equivalent to infant urine). Dripping speed is 3.5sec/25CC
And so. This was defined as the permeation rate (sec/5 cc).

Next, artificial urine is added as is, so that the total liquid volume is approximately four times the absorbent weight so that the liquid volume contained in the absorbent body is constant. A load of 800 g/10 cm square was applied from above the test cloth for 3 minutes to stabilize the distribution of the liquid in the absorbent body. Next, a pre-weighed amount of filter paper (Eaton
Manufactured by Dike+++an) "631, 12.5c+
(n square x 2 sheets) and immediately weigh 3600 g / 10
Load of angle c + n (equivalent to the load applied to an infant's diaper)
for 2 minutes, measure the increase in weight of the filter paper, and calculate the amount of rewetting (
g). Similarly, low load 130g/10c
The amount of rewetting (g) at the +n angle and the high load 5000 g/10G angle was measured, and changes in the load and the amount of rewetting were observed.

◎ Tensile strength, elongation at break, and modulus of 5% in the vertical direction Take samples of the nonwoven fabric in aCJ in both the vertical and horizontal directions, and perform a tensile test using a Tensilon trowel manufactured by Toyo Baldwin, with a grasping interval of 10 cm, and a tensile speed of 30 cm. , tensile strength (kg/3cm width), elongation at break (%), and stress at 5% elongation in the vertical direction as 5% vertical modulus (in kg/3cm).

◎ Flexibility The bending flexibility of JIS L1096 was measured using the E method (6°19.5 handle-o-make method).

Implementation-1 Polypropylene (MFR-38
Measured under condition 4 of JIS K7210 table) at extrusion temperature 24
0℃Nite 1300 g/**Quantitative extrusion, 15
40* - irregular triangular cross-section nozzle (220 mm in the longitudinal direction)
Longitudinal direction 1 with rows (evenly spaced in 7 columns in the width direction)
By using a rectangular spinneret with a width of 5 cm, a group of irregularly shaped filaments was spun, and this was pulled at a speed of 3500 m/min by using a rectangular high-speed airflow traction device,
After being charged with a charging device at this outlet, a web was formed in a wire mesh web container equipped with a moving suction device.

A distance of 50 cm in the direction of filament running is provided between the spinneret and the rectangular high-speed airflow traction device for cooling the filament group.
a first cooling device 12 having a length of
A second cooling device 13 with a length of 5 cm is located closer to the spinneret surface.
Attach the cooling air (70'3A!R,H) perpendicular to the running direction of the filament group.

20°C). The upper end of the cold air blowing position of the first cooling device 12 is 15 cm from the spinneret surface, and the cooling air speed is 1
．． Om/sec, and in the second cooling device 13, it was 5 cm and 0.5 m/sec. Also, the blowing direction of cold air from the first cooling device and the second cooling device is 10° in the horizontal plane.
made a difference. The filaments constituting the obtained bulky long fiber web have an average number of crimps of 10/251.

This web is conveyed by a wire mesh conveyor 16, and is transported as shown in FIG.
1) Transverse line pattern (2.6 m/m x 0.4+n length, minimum interval 1.2 mm, thermocompression bonding area ratio 11.4%, depth 0
．． The upper and lower rolls are both 135°C and 60kg using a thermocompression roll 17 that combines a 6m/m> engraving roll and a smooth roll.
A bulky spunpond nonwoven fabric with a basis weight of 20 g/M was obtained by partial thermocompression bonding at a pressure of /cm. 0.5% of a nonionic water-permeable liquid agent (octylphenol ethylene oxide (8 to 10 mol) adduct) was added to this nonwoven fabric as a treatment agent.

The crimped helical diameter of the filaments in the spunpond nonwoven fabric of Example 1 thus obtained was 0.811, and the average interval at which twist occurred in the longitudinal direction of the filaments was 10 m1. The t obtained from the cross-sectional photograph of the constituent filaments is 865μ, l
The fiber diameter was 13μ, and the single yarn denier was 2.2 denier.

FIG. 2 shows the change in thickness of the nonwoven fabric of the present invention in Example 1 with respect to compressive load, and FIG. 1 shows the change in the amount of rewetting with respect to compressive load. In addition, various physical property values are shown in Table 2. As can be easily seen from FIGS. 1 and 2, the nonwoven fabric of the present invention of Example 1 shows little change in thickness even under a high compressive load of 7°, and also has a small amount of curling.

When this nonwoven fabric is used as the top sheet of a disposable diaper, it has a fluffy and soft feel that does not make you feel the feel of the absorbent material underneath, and it does not feel wet even after absorbing liquid. Ta.

(My husband refused) Using the web obtained in Example 1, we changed the speeds of the conveyor, thermocompression roll, and winding machine to obtain a fabric weight of 15 and 18°25g.
/rn' was obtained. Changes in thickness of these nonwoven fabrics with respect to compressive load are shown in FIG. 3, and various physical property values are shown in Table 2.

Fusen coal 1 The distance from the spinneret surface of the upper end of the cold air blowing position of the first yarn cooling device 12 and the second cooling device 13 is 20, respectively.
cm and 10 cm, and the cooling air speed is 1.0 m/se in both cases.
20 g/rt under the same conditions as Example 1 except for c.
A spunpond nonwoven fabric having a fabric weight of r was obtained.

The crimped helical diameter of the obtained nonwoven fabric was Q, 9 mm, and the average value of the intervals at which twist occurred in the longitudinal direction of the constituent filaments was 11 m1+. The thickness of the nonwoven fabric is 560μ (1
0 g/4 ct load), and the flexibility was 12.3 g in the vertical direction and 5.0 g in the horizontal direction. The cross-sectional shape of the filament is trilobal, t is 8.5 μ, l is 12
It was μ.

The permeation rate of this product through artificial urine is 2.3 sec/5
cc.

The amount of wetness was 87cm (3600g/10cm square load).

Actual difference ↓ The fabric weight is 20 g/min under the conditions of Example 1, except that the engraving pattern on the thermocompression roll is a pinpoint pattern as shown in Figure 11 (2) or a herringbone pattern as shown in Figure 11 (3). A spunbond nonwoven fabric of m was obtained. The physical properties of the obtained nonwoven fabric were
Shown in the table. The larger the minimum interval between the engravings on the thermocompression roll, the deeper the engraving, and the smaller the thermocompression bonding rate, the more flexible and bulky the roll was, but as the interval became larger, the surface tended to become fluffy. . However, no fuzz was observed when compared to the same engraving pattern on an uncrimped web.

A spunbond nonwoven fabric of 20 g/m was obtained under the same conditions as in Example 1 except that a spinneret with a round cross-section and a short spinneret was used.

Although there were crimps in the web before thermocompression bonding, the number of crimps was as small as 3/25 am, and the thickness of the obtained nonwoven fabric was 320 μm, lacking in bulk. The permeation rate of this artificial urine is 2.63ec15cc.
The amount of wetness was 95 cm (3600 g/100 square load).

This MU reduction% The filament obtained from the conventional spunbond nonwoven fabric of 20 g/rd under the same conditions as Comparative Example 1 except for removing the second cooling device 13 had no crimp and was good in terms of strength but flexibility. , it lacked bulk. Table 2 shows the physical properties of the obtained nonwoven fabric.

Hokkai Shoshin Polypropylene-Polyethylene Composite Fiber (113dX5
14m) short fibers are carded and treated with hot air to develop crimp and adhesive properties.
g/rr was obtained. A microscopic photograph of this nonwoven fabric is shown in Figure 15.
As shown in the figure. Table 2 shows the physical properties of the obtained nonwoven fabric. As shown in FIGS. 1 and 2, although the nonwoven fabric of this comparative example is bulky due to the effect of crimping, as the compressive load increases, the degree of deformation increases and the amount of rewetting increases significantly.

A 20 g/rrf spunbond nonwoven fabric for sanitary materials was obtained under the same conditions as in Example 1 except that the spinning nozzle was changed to a V-shaped nozzle with an irregular cross section.

The obtained nonwoven fabric is composed of crimped fibers having a ■-shaped cross section as shown in Fig. 16, and the diameter of the crimped helix is l,
Q n+, it was torsion. The thickness of the nonwoven fabric is 480μ, and the flexibility is 14.0 g/in the vertical direction and 5.0 g/in the horizontal direction.
It was 8g. The permeation rate of this artificial urine is 2.5 s
ec, the amount of wetness is 92■/(3600g/
10 cm square load).

〔Effect of the invention〕

Since the disposable sanitary material according to the present invention is configured as described above, it has excellent performance in terms of texture and wettability, and also has sufficient various properties during the production and use of sanitary materials such as disposable diapers and sanitary napkins. Because of its properties, it has been usefully used as an excellent sanitary material.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the rewetting properties and load of nonwoven fabrics of examples and comparative examples of nonwoven fabrics used as top sheets of disposable diapers of the present invention (hereinafter referred to as nonwoven fabrics of the present invention), and FIG. is a graph showing the thickness change with respect to the compressive load of each of the nonwoven fabrics shown in FIG. 4 is a plan view showing an example of the structure of a disposable diaper, FIG. 5 is a sectional view of the disposable diaper shown in FIG. 4, and FIG.
The figure is an example of a sectional view of filaments constituting the nonwoven fabric of the present invention, and FIG. 7 is a perspective view illustrating the twisting mechanism of the filaments constituting the nonwoven fabric of the present invention.
Figure A shows the state in which the filament immediately after spinning is cooled asymmetrically while being twisted, Figure 7B shows the filament in the state where the filament made in this way is being taken off, and Figure 8 shows the filament in the state where the filament made in this way is being taken off. FIG. 9 is a diagram schematically showing the shape of filaments constituting the nonwoven fabric of the invention, FIG. 9 is a diagram schematically showing the shape of filaments in a conventionally known long fiber nonwoven fabric, and FIG. FIG. 11 is a side view showing an example of the apparatus, and FIG.
1 (6), FIG. 12 is a micrograph showing a cross section of the fiber shape in a portion including a partial thermocompression bonded part of an example of the nonwoven fabric of the present invention, and FIG. FIG. 13 (1) is a cross-sectional view, FIG. 13 (2) is a model diagram showing the bonded state of fibers, and FIG. 14 is a diagram explaining the function of the partial thermocompression bonding section. FIG. 14 (1) is a cross-sectional view, and FIG. 14 (2) is a model of the bonded state of fibers. FIG. 15 is a micrograph showing the shape of fibers in a nonwoven fabric having the bonded state shown in FIG. 14, and FIG. It is a micrograph showing the shape of fibers. 1... Disposable diaper, 2... Top sheet, 3...
...Absorber, 4...Liquid-impermeable back sheet, 5...Granny 16...Tape fastener, 7...
Thermocompression bonding part, 8... fiber, 11... cap,
12... First cooling device, 13... Second cooling device, 14... High speed traction device, 15... Charging device, 16... Wire mesh conhair, 17... Partial thermocompression bonding roll, 18... Liquid permeable agent processing device, 19... Winding machine, 20.
...Web, 21...Nonwoven fabric. O1 Nonwoven fabric of the present invention (Example 1) b = Conventional spunbond nonwoven fabric (Comparative Example 2) C: Conventional short fiber nonwoven fabric (Comparative Example 3) q; Nonwoven fabric of the present invention (Example I) b: Conventional spunbond nonwoven fabric (Comparative Example 2) C: Conventional short fiber nonwoven fabric (Comparative Example 3) O Nonwoven fabric of Example I (Basic weight 209/rr?) d: Nonwoven fabric of Example 2 (Basic weight 1'5g/4F?) e: Example Non-woven fabric of Example 2 (Weight: IEH'/2) f: Non-woven fabric of Example 2 (Weight: 259/♀) Figure 3 Figure 5 Figure 6 Figure 7 Figure 9 Figure 10 (+) (2) f, Figure 11 Figure 12 Figure 13

Claims (1)

[Claims] 1. A disposable sanitary material comprising a top sheet that is permeable to liquid discharged from the human body, a liquid-impermeable back sheet, and an absorbent body located between the front and back sheets, wherein the top sheet has an irregular cross section. 1. A disposable sanitary material characterized in that it is a nonwoven fabric in which a web consisting of continuous filaments of crystalline thermoplastic fibers having crimps is bonded by partial thermocompression bonding applied uniformly over the entire surface of the web.