JPS59157366A - Water pervious and wetting controllable long fiber nonwoven fabric - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides water-permeable, ? ! a
It is a long fiber non-woven fabric with moisture-suppressing properties. Lamination in the present invention simply means overlapping, and ``for lamination'' means using overlapping.

Liners used by laminating on top of cloth diapers, disposable diapers, top sheets used by laminating with liquid absorbing layers such as incontinence pads, etc. have good water permeability against large amounts of water locally, and once they are water permeable. and apply N to the liquid absorption layer.
It is necessary to have moisture inhibiting properties so that the accumulated liquid will not be absorbed. Water permeability and moisture suppression properties are mutually contradictory properties, and it is extremely difficult to satisfy both at the same time. The conventional method of satisfying both of these properties at the same time is to use a thick knitted fabric made of hydrophobic synthetic fibers. I seek gender in the space between the stitches of the knitted fabric. However, when knitted fabrics using 9 synthetic fibers come into direct contact with the skin of the buttocks, etc., they feel particularly bad and even cause discomfort. Therefore, methods of using soft non-woven fabrics as a material that feels good on the skin have been considered, but due to the leaky nature of nylon itself, non-woven fabrics using nylon fibers have good water permeability but poor moisture control properties. 2. Once permeated, the water tends to be absorbed again. On the other hand, long-fiber nonwoven fabrics using regular polyester fibers (polyethylene terephthalate fibers) and polypropylene fibers have a tendency to absorb moisture again due to the hydrophobic nature of the fibers themselves.

Although moisture suppression properties are good, sufficient water permeability cannot be satisfied, and to this day, a soft nonwoven fabric for lamination with a liquid absorbing layer that satisfies water permeability and moisture suppression properties at the same time has not been obtained. .

In view of the current situation, the inventors of the present invention have conducted extensive research, and have developed a technology that uses polyethylene terephthalate fibers and isophthalate copolymerized polyethylene terephthalate fibers, and combines this with heat-pressing means using special embossing rolls to produce the product using the spunbond method. The present inventors have discovered that by carrying out the following steps, it is possible to obtain a soft nonwoven fabric for lamination with a liquid absorbing layer that satisfies water permeability and moisture suppression properties at the same time.

That is, 1 the present invention is a uniform mixture of polyethylene terephthalate fibers as the main constituent fibers and Isofukure 1 to copolymerized polyethylene terephthalate 1 fibers as the sub-constituent fibers, with a basis weight of 10 to 30 g/I and a density of 0.13 to 0. 21g/cr
A long-fiber nonwoven fabric having countless discontinuous heat-pressed fine patterns formed by embossing rolls on the surface of the nonwoven fabric, and at the contact points between the sub-constituent fibers and the contact points between the sub-constituent fibers and the main constituent fibers. This is a water-permeable, moisture-suppressing long-fiber nonwoven fabric for lamination with a liquid absorbing layer, characterized in that the contact portions are joined in many respects by partial thermal fusion of sub-constituent fibers.

Two aspects of the present invention will be described in detail below.

The nonwoven fabric for lamination with the liquid absorbing layer of the present invention is firstly made of a uniform mixture of polyethylene terephthalate fibers as the main constituent fibers and isophthalate copolymerized polyethylene terephthalate l-fibers as the sub-constituent fibers, and has a basis weight of 10 to 10. 30 g/r
(d) It is necessary to be a long fiber nonwoven fabric with a density of 0.13 to 0.21 g/ct (b).

If the nonwoven fabric is mainly composed of polyethylene terephthalate fibers, it has poor water permeability as mentioned above, and to improve this water permeability, attaching surfactants such as various sulfonates and ammonium salts can improve water permeability. However, in the present invention, polyethylene terephthalate fiber is used as the main constituent fiber, and in addition to this, the isophthalate component is added. By mixing polymerized polyethylene terephthalate fibers (hereinafter referred to as isophthalate copolymerized polyester fibers) as sub-constituent fibers, we succeeded in simultaneously satisfying both water permeability and moisture suppression properties. Why is it possible to simultaneously satisfy water permeability and moisture suppression properties when isophthalate copolymerized polyester fiber is used in combination with polyethylene terephthalate fiber, which is the main constituent fiber? Although it is not necessarily clear why, the present inventors have It is inferred as follows. Naturally, this is achieved based on the relationship with the basis weight, density, discontinuous heat-pressure welding, etc. described later, but generally, isophthalate copolymerized polyester fibers are hydrophobic fibers, so they have moisture suppression properties. Despite this, polyethylene terephthalate fibers do not have strong hydrophobic properties, so when a large amount of water is applied to a particular area, the force that can ripple it does not work, allowing it to permeate through the nonwoven fabric. It is considered to exhibit good water permeability.

The copolymerization ratio of the isophthalate component in the isophthalate copolymerized polyester fiber used in the present invention does not require any restriction from the viewpoint of the performance of the nonwoven fabric, but from the viewpoint of manufacturing the nonwoven fabric, it is 6 to 15%. It is preferable that the amount of copolymerization be within the range of mol %.

However, if the copolymerization ratio of isophthalate is high, the softening point of the copolymer will be too low and fusion will occur when drying the chips before spinning, so drying cannot be carried out at a very high temperature9. It takes a long time of 24 to 48 hours at a relatively low temperature, and the equilibrium moisture content is at the limit of not causing spinnability, that is, 0.01% (100 ppm).
Furthermore, the higher the proportion of isophthalate components, the worse the thermal properties are.2 For example, when heating and pressurizing the fibers that make up the nonwoven fabric, large thermal contractions occur and the product deteriorates. This is due to reasons such as poor internal control, wrinkles, etc., which make it difficult to produce a spunbond nonwoven fabric of the direct spinning type.

However, if the proportion of isophtha 1-1 is too small (below 6 mol %), the difference in softening point from the main constituent fiber, polyethylene terephthalate, will be too small and a high temperature will be required during heating and pressing.

The characteristics of incorporating adhesive fibers are not achieved, and the effects of the present invention are also not achieved.

The proportion of isophthalate copolymerized polyester fibers mixed into the nonwoven fabric of the present invention is preferably 10 to 30% of the total weight of the nonwoven fabric. Isophthalate copolymerized polyester fiber is also a fiber for bonding the contact points between fibers, and the reason why the proportion of this bonding fiber is too small and the bond is insufficient is because the fiber has a cotton-like fluffy structure. However, the water permeability is poor due to the surface tension of the liquid, and on the other hand, if the proportion of adhesive fibers is greater than the amount sufficient to obtain the strength required of the nonwoven fabric, the fabric will have a hard and bulky feel.

From the above, it is suitable that the proportion of adhesive fibers is 10 to 30% of the total weight of the nonwoven fabric.

Regarding the proportion of adhesive fibers, the relationship with the fineness of the adhesive fibers cannot be overlooked. This is because if the fineness of the bonded fibers is thin, the fiber length will be longer when compared in terms of weight, and the number of fiber entanglement points, that is, bonding points, will increase.
Since adhesion is carried out effectively, it is possible to manufacture a non-woven fabric with at least sufficient strength when the ratio of adhesive fibers is large.On the other hand, if the ratio of adhesive fibers is too thick, the adhesive strength will be insufficient unless the ratio is increased, and sufficient strength cannot be obtained. I can't do it.

By the way, the thinner the denier of the fibers that make up the nonwoven fabric, the softer the texture of the sheet, but from the perspective of spinnability, the thinner the fiber, the worse the spinnability. There is a limit to the number of holes that can be made, and it is not possible to spin that many yarns, so productivity is lower than when spinning thick yarn with the same number of holes.

For these reasons, a fineness of 1 G and 3 denier is usually used for nonwoven fabrics that require a soft texture.
Under such conditions, the denier range of the bonding fibers is limited to about 50% of the fineness of the main constituent fibers at most, even if the denier is made as thin as the main constituent fibers.

The basis weight of a nonwoven fabric and the proportion of adhesive fibers among the fibers that make up the nonwoven fabric are determined by taking into consideration the texture and strength of the sheet, water permeability and moisture control properties, as well as production cost, etc. 10 to 30 for 14 inches
g/rd, preferably 15 to 25 g/m
is appropriate.

Naturally, the higher the basis weight, the higher the strength, but the texture becomes harder, which is disadvantageous in terms of cost, and 30g/
r+? If it exceeds the permeability level of the liquid, it will become a resistance and it is not good.More strangely, when it is used as a knob sheet for disposable diapers, its moisture suppression properties are inferior (as it turns out). did.

The fiber density of the nonwoven fabric of the present invention is also related to the above-mentioned basis weight, but
The thickness is preferably in the range of 0.13 to 0.21 g/cta, and may be appropriately selected within this range depending on the required performance and texture. In addition, the fiber density of the nonwoven fabric is determined by the weight per unit area and the unit area load M 240 fg.
It is calculated as the value divided by the product of /cJ and the thickness measured with a dial thickness gauge.

Roughly speaking, the nonwoven fabric of the present invention has numerous fine patterns formed by discontinuous heat-pressure welding by embossing rolls on its surface. This fine pattern is applied by an embossing roll during the thermo-pressure welding process of nonwoven fabrics, and this embossed pattern is created by continuous pressure welding (shaded areas) rather than continuous pressure welding (shaded areas) as shown in Figure 1 a and b. For example, dot shapes, wavy lines, etc. as shown in c, d, e, and f in FIG. 2 are suitable.

This is because nonwoven fabrics that are pressed with a flannel roll that covers the entire area of the nonwoven fabric, or those that have an embossed pattern with a large area of pressure contact, or those that are continuous even if the area of pressure contact is small, generally have a hard texture, and the film It is a non-woven fabric, which not only feels bad on the skin but also has poor water permeability.

On the other hand, if the pressure contact area is too small, pressure contact will be insufficient.

This results in a weak nonwoven fabric that lacks strength and tends to fluff, and also has poor water permeability due to the surface tension of the liquid.

Therefore, the pressure contact area is suitably 8% to 25% of the total area, preferably 10% to 20%.

In addition, in the nonwoven fabric of the present invention, the contact portions of the sub-constituent fibers, which are isophthalate copolymerized polyester fibers, and the contact portions of the sub-constituent fibers and the main constituent fibers (polyethylene terephcrate fibers) are the sub-constituents at many points. The fibers are joined by partial heat fusion.

This heat fusion bonding does not need to be performed at all the contact points of the sub-constituent fibers, and the temperature and linear pressure of the embossing roll can be adjusted according to the required texture and strength of the nonwoven fabric. The bonding ratio can be selected as appropriate.

In the nonwoven fabric of the present invention, from the viewpoint of water permeability, it is necessary that the sub-constituent fibers themselves exist in the state of fibers, and therefore, the sub-constituent fibers are joined by thermal fusion only partially at the contact points of the fibers. Although it is necessary to join by thermal fusion, some degree of complete thermal fusion is fine as long as it does not impair the effects of the present invention.

The nonwoven fabric for lamination with the liquid absorbing layer of the present invention having the above structure has both water permeability and moisture suppression performance at the same time, and therefore, its good water permeability allows it to easily absorb a large amount of water locally. At the same time, due to its moisture-inhibiting properties, water that has penetrated and accumulated in the liquid-absorbing layer cannot be absorbed or removed, so the surface of the non-woven fabric can be kept as if it were dry by keeping it dry. I can do it.

When producing the nonwoven fabric of the present invention, a spunbond method is adopted, and polyethylene terephthalate fibers are used.

After melt spinning, drawing, and opening deposition from different holes of the same spinning rig, the number of spinning holes and spinning hole diameter are adjusted so that the isophthalate copolymerized polyester fiber is the main constituent fiber and the isophthalate copolymerized polyester fiber is the secondary constituent fiber. 5 Next, thermo-pressure welding is carried out at a temperature that causes partial thermal fusion of the fibers while controlling the surface temperature using an embossing roll having discontinuous fine pressure-welding holes as shown in FIG. The nonwoven fabric of the invention can be manufactured.

The nonwoven fabric of the present invention has water permeability and moisture suppression properties, and has been developed for lamination with a liquid absorbing layer. Therefore, the nonwoven fabric of the present invention is extremely useful as a top sheet for disposable diapers, a liner for general diapers, or a top sheet for incontinence pads, belly button bands, menstrual bands, etc., and has particular practical value for use in disposable diapers. is high.

When manufacturing disposable diapers using the nonwoven fabric of the present invention, the thickness of the liquid-impermeable bank sheet is about 0.02 mm.
5-0.05mm polyethylene film.

A polypropylene film, a nylon film 1 f ester film, etc. is used, and on top of that, crushed wood pulp or multilayered toilet paper/filter paper is layered as a liquid absorption layer, and the water permeable, moisture suppressing nonwoven fabric of the present invention is applied on top of this. A disposable diaper can be manufactured by stacking them and molding them into one piece using a conventional method.

The present invention has the above-described structure, and if this nonwoven fabric having both water permeability and moisture suppression properties is used for lamination with a liquid absorbing layer, urine, excreted fluid, etc. can be easily transferred to the liquid absorbing layer. Not only that, but it also prevents the backflow, so various sanitary products that are extremely comfortable to wear can be obtained, and have extremely high industrial utility value.

Next, specific examples of the nonwoven fabric of the present invention and their effects will be explained using examples.The methods used to determine water permeability and moisture suppression properties in the examples are as follows, and they are based on the assumption that they will be used when actually wearing a diaper. It is something.

The sample, i.e. the top surface of the sheet, has an inner diameter of 3 cm and a height of 1
Place a stainless steel ring of 1.5 cm in diameter, and place 5 filter papers of Qualitative Teeth 2 (manufactured by Toyowagaku Sangyo) with a diameter of 9 cm on the bottom surface of Sea 1. In this state, from a height of 2 cm above the sheet, Drop 5 cc of water and measure the time from the moment it falls onto the sample until the water completely covers the sheet and no longer produces any special reflection (specular reflection) on the top surface of the sheet. Gender was evaluated.

On the other hand, regarding the moisture suppression property, a qualitative hole 2 with a diameter of 9 cm (
Oriental Science and Industry Layer) Measure the weight of 5 filter papers, size 2
Place it on a 0cm x 20cm glass and add 4 times the weight of water to the filter paper from the billet.
A sample cut to a size of 15 cm was placed on top of the sample, and the weight was further measured using a quantitative tooth 6 with a diameter of 12.5 cm (
Place 5 sheets of filter paper (Toyo Kagaku Sangyo Layer) on top of the sample. Once the above preparations are complete, immediately make a size 10cm x 10cm.
, slowly put a load of 4 kg around the center of the whole -
Let stand for 3 minutes, then remove the load, weigh 5 filter papers of quantification level 6 with a diameter of 12.5 cm placed on the sample, and calculate the weight of water absorbed by the filter paper. By sea 1
− was evaluated for the moisture suppression property.

During measurement, the temperature of the filter paper and sample was 20±2°C.

The sample was allowed to stand for 24 hours or more in a room whose humidity was adjusted to 60±5°C, and measurements were taken in the same room.

Example 1 75% by weight of polyethylene terephthalate fiber with a fineness of 3 denier as the main constituent fiber, and isophthalate copolymerized polyester fiber with a fineness of 2 denier as the secondary constituent fiber (the copolymerization ratio of the isophthalate component and the terephthalate component is 1)
Each fiber was simultaneously melt-spun, drawn, and opened from separate holes in the same spinneret using the spunbon method so that the fibers (2:88) were uniformly mixed at a ratio of 25% by weight per l ct. 15 g, and then, without using any emulsion type adhesive, a rectangular non-continuous fi of 2.5 mm in length and 0.4 mm in width as shown in Fig. 2 FDL was deposited.
The surface temperature was 195'C using an embossing roll with an I-type pressure pattern (the area of the fine pressure pattern on the roll was 11.0%).

A long-fiber nonwoven fabric for lamination with the liquid absorbing layer of the present invention was obtained by thermal welding at a linear pressure of 25 kg/cm and a cloth speed of 48 m/min. This nonwoven fabric has a basis weight of 15 g/m.

It has a density of 0.15 g/c+d and has countless discontinuous thermo-compression welded fine patterns on its surface, and is stabilized by being joined by heat fusion at many points at the contact points of the sub-constituent fibers. It was a non-woven fabric (referred to as ``Minami 4'').Moreover, in the non-pressure contact area of the embossing roll, there was almost no bonding at the contact points between the main constituent fibers, so it was a non-woven fabric with a very soft texture. .

The water permeability and moisture suppression properties of the nonwoven fabric of the present invention were measured using the methods described above, and the results are shown in Table 1.

For comparison with the nonwoven fabric of the present invention, the following nonwoven fabric sheet floor 1
-3 comparative samples were prepared, and the water permeability and moisture suppression properties were similarly measured, and the results are shown in Table 1.

First, a fabric with a fabric weight of 15 g/m was made of polyethylene terephthalate with a fineness of 3 denier bonded using an emulsion type adhesive of polyacrylic acid ester.

Non-woven fabric with density 0.16 g/ca (sheet Il&ll
) was measured for water permeability and moisture suppression.

The results are shown in Table 1, seat level 1.

Although it has very good water permeability and allows water to pass through it quickly, it has no ability to suppress wettability and allows a large amount of water to seep out.

On the other hand, sheet 11k12, which is the same nonwoven fabric as sheet lkl and coated with 0.15ffi of a fluorine-based water repellent, and sheet 11k12, which is made of a nonwoven fabric coated with 0.15ffi of a fluorine-based water repellent, and sheet 11k12, which is made by heat-pressing only polyethylene terephthalate fibers without using an emulsion type adhesive, have a basis weight of 15
g/m, density 0.14 g/cIll nonwoven fabric (sheet).

h > 3) was similarly measured for water permeability and moisture suppression properties, and found that both water permeability was extremely poor (see Table 1), making it unsuitable for use as a 1-knob sheet for disposable diapers.

On the other hand, the nonwoven fabric of the present invention exhibits good water permeability comparable to that of sheet floor 1 using an emulsion type adhesive, and has suppressed wettability like sheet floor 1, floors 2 and 3, and is water-resistant. The sheet was difficult to get wet.

-1 Here, the above-mentioned nonwoven fabric of the present invention is used as the top sheet 1 of a disposable diaper, and a liquid absorption layer (fabric weight 350 g/m) and integrally molded using a conventional method to produce a disposable diaper, liquids such as urine excreted by the wearer are quickly absorbed by the absorbent layer on the lower surface of the top sheet, and even more so than the wearer. A disposable diaper with good surface drying properties was obtained, with no moisture seeping out onto the top sheet surface even after compression under the weight of the top sheet.

Example 2 In producing the nonwoven fabric of the present invention in Example 1, the proportions of the sub-constituent fibers Isoftathy 1 to copolymerized polyester fibers were 10% by weight, 9% by weight, and 25% by weight.
The present invention was carried out in exactly the same manner as in Example 1, except that the temperature was set to 40% by weight, and the pressure welding pattern of the embossed roll was a dotted pattern (pressure serum 13%), and hot pressure welding was carried out at a roll surface temperature of 195°C. Four types of nonwoven fabrics were manufactured (Seal No. 5, 6, 7, and 8, respectively). The performance of the obtained nonwoven fabric was determined by IIJ.

The results are shown in Table 2. As is clear from Table 2, isophthalate copolymerized polyester fiber (adhesive fiber)
As the proportion of 5 increases, the water permeability and moisture control properties tend to become better.Those with a small proportion of adhesive fibers are somewhat lacking in strength and water permeability, and those with a large proportion of 5 have a slightly hard and stiff texture. However, all of them satisfied the required performance as a top sheet for disposable diapers.

Table 2 Example 3 In order to investigate the relationship between the performance and basis weight of the nonwoven fabric of the present invention, the nonwoven fabric sheet N117 of the present invention (contact MI
When manufacturing A-fiber mixed ratio of 25% by weight), the mesh size was set to 10 g/m and 20 g/n (25a/rr, respectively).
r.

30 g/rd and 40 g/g, respectively.
0. II, a nonwoven fabric of 1.2.13 was obtained.

These non-woven fabrics have water permeability and ll! The moisture suppression properties were measured and are shown in Table 3 together with that of sheet No. 7. It is clear from Table 3 that as the basis weight increases, the water permeability and moisture suppression properties deteriorate. From this, the basis weight of a top sheet for disposable diapers is at most 30 g/rrr.

Although it can be said that 25 g/n (desirably) is the limit, it can be used sufficiently even with a basis weight of 10 g/r&.

It can be said that it is somewhat lacking in power.

Table 3 1 ratio 1 1 Ill l
11 comparison 1 Yang 131 40 1 6.01 3.1
1 5.3 l 1.25 l) 111
l l l l l 1

[Brief explanation of the drawing]

FIGS. 1 and 2 are examples of pressure contact patterns of embossing rolls, and the hatched areas are the pressure contact portions of the sheet. Figures 1a and b show continuous pressure welding parts, and Figures 2c, d, e, and f show examples where the pressure welding parts are not continuous, such as points or broken lines. A pattern like this is desirable. Patent applicant Unijinriki Co., Ltd.

Claims (1)

[Claims] (]) Fabric weight: 10 to 30 g /
m, a density of 0.13 to 0.21 g/cflI, a long fiber nonwoven fabric having countless fine patterns discontinuously welded by heat and pressure by embossing rolls on the surface of the nonwoven fabric, and contact areas between the sub-constituent fibers. and "2) for lamination with a liquid absorbing layer, characterized in that the contact points between the sub-constituent fibers and the main constituent fibers are joined by partial thermal fusion of the sub-constituent fibers at many points of contact. Water-permeable, moisture-resistant long fiber nonwoven fabric.