JPS63246159A - Absorbable article - 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 [Industrial Application Field] The present invention relates to an absorbent article, and specifically, (A) a water-absorbing polymer, (B) a water-insoluble inorganic substance, and (C) a water-insoluble hydrophilic fibrous substance. The present invention relates to body fluid-absorbing articles such as sanitary napkins, disposable diapers, breast-feeding pads, postpartum pads, incontinent pads, hemorrhoid pads, and surgical pads, which are characterized by containing a liquid-absorbent composite consisting of the following.

[Conventional technology and its problems]

Many studies have been conducted to improve the absorption characteristics of absorbent articles, and many results have been reported.

Most of the goals are to increase the rate of absorption, to prevent liquid from returning to the surface after absorption, and to reduce stickiness on the surface.

To give a specific example, research on surface materials revealed that rayon staples, which have been commonly used in the past, have a sticky surface because they are hydrophilic. Proposals have been made to reduce the stickiness of the surface by changing it to a hydrophobic material such as polypropylene staple or polyester staple.

In addition, as a material for absorbent bodies, polymer absorbent materials (
It has been proposed to improve the absorption capacity by applying a super absorbent polymer (superabsorbent polymer) and at the same time prevent the liquid from returning to the surface material after absorption.

However, although conventional superabsorbent polymers have excellent absorption properties for low viscosity and low ionic strength solutions such as water and urine,
Absorption of highly viscous solutions such as blood, pus, and loose stools is poor, and even if a water-absorbing polymer is included in an absorbent body, it has little effect at present. In addition, in order to improve the absorption performance for such highly viscous liquids, polymers have been made porous (Japanese Unexamined Patent Publication No. 59-8711) and organic and/or inorganic water-soluble salts have been added (Japanese Patent Publication No. 58-501107).
(Japanese Unexamined Patent Publication No. 1983), mixing with hydrophilic fibers such as pulp
86657) have been proposed, but it is still difficult to say that their effects are sufficient.

Therefore, the emergence of an absorbent article that exhibits excellent absorbency even for highly viscous liquids is eagerly awaited.

[Means for solving problems]

Therefore, the present inventors conducted intensive studies to obtain an absorbent article that has excellent absorbency even for highly viscous liquids such as blood, and as a result, completed the present invention.

That is, the present invention is a liquid-absorbing composite consisting of (A) a water-absorbing polymer, (B) a water-insoluble inorganic substance, and (C) a water-insoluble hydrophilic fibrous substance, and the composite ratio (weight ratio)
is (A): (B): (C) = 100:5
The present invention provides an absorbent article containing a liquid absorbent composite having a molecular weight of 120,025 to 1,200.

The absorbent composite according to the present invention is obtained by adding a specific amount of a water-insoluble inorganic substance and a water-insoluble hydrophilic fibrous substance to a water-absorbing polymer and immobilizing the same. It has excellent absorption performance not found in other countries.

The water-absorbing polymer used in the present invention may be any polymer that generally has absorbency.
For example, in addition to water-soluble ethylenically unsaturated polymers containing poly(meth)acrylic acid or its salt as a main component and optionally adding a crosslinking agent, crosslinked products of polyethylene oxide, polyvinylpyrrolidone, sulfonated polystyrene, and polyvinylpyridine , saponified starch-poly(meth)acrylonitrile graft copolymer, starch-poly(meth)acrylic acid (and its salt) graft copolymer (and its crosslinked product), starch-poly(meth)acrylic ester graft copolymer Examples include polymers (and crosslinked products thereof), hydrolysates of starch-poly(meth)acrylic ester graft copolymers, and the like. Further examples include polyvinyl alcohol sulfonate, polyhinyl alcohol-acrylic acid graft copolymer, and the like. Preferably,
It is a polymer of water-soluble ethylenically unsaturated monomers containing acrylic acid or acrylate as a main component, or a crosslinked product thereof, and any production method may be used.

Two or more types of these polymers may be used.

The water-absorbing polymer is a polymer that absorbs water at an amount of 20 mZ/g or more, and can be in the form of powder, granules, lumps, sheets, etc. In order to produce the composite of the present invention, any of these polymers can be used. is also available. In the case of powder or granules, the particle size is 10 to 3000μ, preferably 15 to 100μ.
0- is good.

The inorganic substance used in the present invention must be substantially insoluble in water, and any substance that satisfies this requirement may be used. Specifically, for example, alumina, silica, titanium dioxide, talc, zirconia, calcium phosphate, barium phosphate, calcium sulfate, clay, silicic acid, diatomaceous earth, bentonite, activated carbon, zeolite, kaolinite, kaolin, acid clay, activated clay, Examples include powders such as verminiculite and other metal oxides. Particularly preferred are alumina, silica, zeolite, montmorillonite clay (bentonite), and kaolinite clay (kaolin).

The particle size of the water-insoluble inorganic substance is not particularly limited, but 15
00 Ja or less is preferably used, especially 5
00- or less are preferably used.

Examples of water-insoluble hydrophilic fibrous substances include cellulose, which has wettability and liquid conductivity characteristic of water-insoluble hydrophilic fibrous substances;
Examples include pulp, rayon, vinylon, cotton, wool, and acetate, with cellulose, pulp, and rayon being particularly preferred. In addition, water-insoluble hydrophilic fibrous materials such as polyester, polyethylene, polypropylene, polyvinyl chloride, acrylic, nylon, etc., which are hydrophobic fibrous materials, are used for the purpose of imparting functions such as diffusivity and immobilization through heat fusion. Can be used with. The mixing ratio of the hydrophobic fibrous substance can be varied within a wide range depending on the application as long as the hydrophilicity is not impaired, but the water-insoluble hydrophilic fibrous substance should be used in an amount of 60% by weight or more, preferably 80% by weight or more. desirable. These forms may be anything from long fibers to short fibers, or finely powdered ones. The fiber length is desirably 50+n or less, preferably 40 am or less.

The composite ratio of the water-absorbing polymer, water-insoluble inorganic substance, and water-insoluble hydrophilic fibrous substance is 5 to 1200 parts by weight of the water-insoluble inorganic substance and 5 to 1,200 parts by weight of the water-insoluble hydrophilic fibrous substance to 100 parts by weight of the water-absorbing polymer. 1200 parts by weight, preferably 10 to 800 parts by weight of a water-insoluble inorganic substance, 10 to 1000 parts by weight of a water-insoluble hydrophilic fibrous substance, more preferably 20 to 500 parts by weight of a water-insoluble inorganic substance, a water-insoluble hydrophilic fibrous substance. 20-800 parts by weight of substance. Even if any of these constituent components is missing, the effects of the present invention will not be recognized and this is not the intention of the present invention. If the content of the water-insoluble inorganic substance is less than 5 parts by weight, the liquid absorption rate and absorption capacity of the water-absorbing polymer will be low, which is not preferable.

If it exceeds 1,200 parts by weight, the amount of liquid absorbed by the composite will be small, and it will not be immobilized in the polymer, making it impossible to achieve the object of the present invention.

In water-insoluble hydrophilic fibrous substances, when the content is less than 5 parts by weight, the liquid conductivity of the water-absorbing polymer, the liquid absorption rate,
Diffusivity is low, and if it exceeds 1200 parts by weight, the amount of liquid absorbed by the water-absorbing polymer becomes small, making it impossible to achieve the object of the present invention.

The composite ratio of the water-insoluble inorganic substance and the water-insoluble hydrophilic fibrous substance can be freely changed within the above range depending on the type of liquid to be absorbed and the use.

The method for producing the liquid-absorbent composite according to the present invention includes:
Although any known method may be used, it is preferably produced by the following method. That is, a method may be mentioned in which a water-insoluble inorganic substance and a water-insoluble hydrophilic fibrous substance are added to the water-absorbing polymer in a sufficiently swollen state. For example, a method in which a swollen polymer, a water-insoluble inorganic substance, and a water-insoluble hydrophilic fibrous substance are added to a kneader mixer, mixed and then dried; a water-absorbing polymer in an organic solvent, water, a water-insoluble inorganic substance, and a water-insoluble hydrophilic fiber; A method in which a water-insoluble inorganic substance and water are mixed in a screw rotating blade mixer, and then a water-absorbing polymer and a water-insoluble hydrophilic fibrous substance are sequentially added in a screw rotating blade mixer. In addition, a method of drying after mixing can be mentioned. Alternatively, a method may be used in which a water-insoluble inorganic substance or a water-insoluble hydrophilic fibrous substance is added to a water-soluble ethylenically unsaturated monomer or a water-soluble ethylenically unsaturated monomer partially containing a crosslinking agent, followed by polymerization and drying. These manufacturing methods are not particularly limited.

Further, the liquid absorbent composite obtained after drying can be subjected to pulverization treatment if necessary. The liquid-absorbent composite of the present invention manufactured in this manner has a bulk specific gravity of 0.03 to
0.7 g/cc, preferably 0.05 to 0
．． 6 g/cc. An ungrooved composite with a bulk specific gravity of 0.03 g/cc becomes too bulky and difficult to handle;
．． If it exceeds 7 g/cc, the desired absorption performance cannot be obtained.

(A) Water-absorbing polymer of the liquid-absorbing composite of the present invention, (B)
The composite state of the water-insoluble inorganic substance and (C) the water-insoluble hydrophilic fibrous substance is as follows.

That is, the water-insoluble hydrophilic fibrous substance and the water-insoluble inorganic substance are composited with the water-absorbing polymer in the following state.

<Water-insoluble hydrophilic fibrous material> ■ Fibers are partially or completely embedded in the polymer.

■Fibers are attached to the polymer surface.

■ Fibers are intertwined with each other, with some fibers embedded in the polymer or attached to the polymer surface.

<Water-insoluble inorganic substance> ■ An inorganic substance is partially or completely embedded in the polymer.

■ Inorganic substances are attached to the polymer surface.

■ Fibrous substances mentioned above> An inorganic substance is attached to the fibers of ■ to ■.

■ Inorganic substances are aggregated together, and some of the inorganic substances are embedded in the polymer or attached to the polymer surface.

In the present invention, examples of composite states of (A) water-absorbing polymer, (B) water-insoluble inorganic substance, and (C) water-insoluble hydrophilic fibrous substance include the above-mentioned ones. is not limited to these, (A)
, (B), and (C) should be substantially combined.

The improvement in liquid absorption by the water-insoluble inorganic substance and the water-insoluble hydrophilic fibrous substance in the liquid-absorbing composite of the present invention was found to be particularly effective for high viscosity liquids, but the effect is as follows. It is thought that this was the result of this.

Since the water-absorbing polymer is coated with a water-insoluble hydrophilic fibrous substance, it has good compatibility with aqueous solutions, and even when the liquid does not come into contact with the polymer, the water-insoluble hydrophilic material coats the water-absorbing polymer. Once it comes into contact with a fibrous substance, the liquid can be carried to the polymer by the liquid-conducting effect of the fibers, causing the polymer to swell.

The inorganic substance used in the present invention is preferably one that is substantially insoluble in water and has some degree of hygroscopicity, and this inorganic substance is partially contained in the polymer. Because it is an inorganic substance that is insoluble in water, it is less affected by salt, and due to the capillary phenomenon peculiar to dense inorganic particle coating,
It is thought that this activates the liquid absorption performance of the water-absorbing polymer.

In a composite of either one of these water-insoluble inorganic substances or water-insoluble hydrophilic fibrous substances and a water-absorbing polymer,
No significant improvement in liquid absorption performance can be expected, and we believe that performance will be improved by combining the three materials, including a water-absorbing polymer.

The above-mentioned liquid-absorbent composite according to the present invention can be a sufficient absorbent by itself, but can only exhibit its original function when combined with other cotton-like or sheet-like materials.

In other words, the liquid-absorbing composite described above can have the liquid retaining space, liquid diffusivity, and shape retention ability of the fiber aggregate only by being incorporated into the capillary structure formed by the fiber aggregate. be.

The material combined with the liquid-absorbing composite absorbs, diffuses, and absorbs liquid.
It is preferable to use fibers that have the ability to retain moisture. Specifically, in addition to cellulose-based hydrophilic fibers such as pulp, rayon, and cotton, polyesters and vinylons that have been subjected to hydrophilic treatment, and alrylic fibers that have a large number of micropores on the fiber surface are preferred. etc.

These have very high hydrophilicity, so they have the ability to quickly diffuse liquid inside the fiber aggregate, and can firmly retain liquid due to strong capillary force.

In other words, these fibers absorb liquid and diffuse it, effectively transporting the liquid to the absorbent composite and retaining the liquid until the composite absorbs the liquid. It is something that fulfills a function.

In addition to the above-mentioned cellulose-based hydrophilic fibers, it is also possible to use synthetic fibers such as polyethylene, polypropylene, polyester, and polyethylene-polypropylene composite fibers, which have a high dry and wet strength ratio, and by using these, it is possible to Since the structural stability of the absorbent body is also increased, it is possible to prevent the absorbent body from twisting and sagging.

That is, it is clear that the performance of the absorbent body can be further enhanced by combining the above two types of fibers as necessary.

Next, various embodiments of the absorbent article of the present invention will be explained based on the cross-sectional view of FIG. 1, but it goes without saying that the present invention is not limited thereto.

FIG. 1(a) shows a sheet-like absorbent body according to the present invention,
The liquid-absorbent composite 4 is evenly spread on the yam or non-woven fabric 3,
After layering another layer of Gion or non-woven fabric 3゛ on top of it, spray a small amount of water in a mist or dry it with steam.
The upper and lower paper or nonwoven fabrics 3.3'' are adhered by the once wet absorbent composite 4 to obtain a sheet-like absorbent body with good flexibility. The amount of liquid absorbent composite 4 to be sprayed is 10g/rrr
Preferably 300g/rrr to 300g/rrr, more preferably 3
0g/rd to 150g/rrr.

FIG. 1(b) shows another embodiment of the sheet-like absorbent body according to the present invention, in which pulverized pulp or cellulose powder 5 and liquid-absorbing composite 4 are mixed and formed into a sheet, and the top and bottom are By sandwiching it with paper or nonwoven fabric 3 and sealing the edges by gluing it, a highly flexible sheet-like absorbent body is obtained.

FIG. 1(C) is a cross-sectional view showing an embodiment of the absorbent article of the present invention, in which the absorbent composite 4 is uniformly scattered on the pulverized pulp layer 5 stacked on the mount 6, Further, the pulverized pulp 5 is stacked on top of the fiber, a mount 6 is placed on top of the fiber, and the whole is wrapped with a waterproof sheet 2 on the lower side and a nonwoven fabric 1 on the upper side. At this time, a cloth or nonwoven fabric 3 may be placed between the absorbent composite 4 and the pulverized pulp layer 5. This structure is mainly suitable for disposable diapers.

FIG. 1(d) is a cross-sectional view showing another embodiment of the absorbent article of the present invention, in which the absorbent composite 4 is uniformly scattered on the pulverized pulp 5 stacked on the mount 6, By laminating 1 to 10 sheets, preferably 3 to 6 sheets of crepe Gion 7, laminating a waterproof sheet 2 on the crepe Gion 7 side, a rayon staple cotton 8 on the crushed pulp side, and wrapping the whole thing with a nonwoven fabric 1. can get. This structure is mainly suitable for sanitary napkins.

〔Effect of the invention〕

The absorbent article of the present invention comprises (A) a water-absorbing polymer, (B)
An absorbent article containing a liquid-absorbing composite consisting of a water-insoluble inorganic substance and (C) a water-insoluble hydrophilic fibrous substance,
It has excellent absorption and retention performance for highly viscous liquids such as blood, pus, and loose stools, which were previously difficult to absorb and retain. This significantly reduces surface stickiness and side leakage.

〔Example〕

Next, the structure and absorption performance of the absorbent article of the present invention will be explained in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

Furthermore, the present invention relates to an absorbent article that has excellent absorbency for highly viscous liquids, and since basically the same concept is possible, the following example uses a sanitary napkin as a representative example of an absorbent article. will be explained in more detail.

The saturated absorption amount, absorption rate, and absorption power of the absorbent composite, as well as the liquid return amount and dynamic maximum absorption amount, which indicate the effectiveness of the absorbent article of the present invention, were measured by the following methods.

In addition, physiological saline was used as a typical example of a low-viscosity fluid, and blood was used as a typical example of a high-viscosity fluid.

(1) Saturated absorption capacity: Soak the dried liquid-absorbent composite in a sufficient amount of horse-drawn (defibrated, sold by Japan Biomaterials Center) or physiological saline,
It was left for 30 minutes.

After that, suction filtration (filter paper! 1kL2, diameter 125W) L,
The weight was measured. A similar operation was performed on a system without absorbent complex (
That is, only the filter paper was used to measure the weight. From these, the saturated absorption amount of the absorbent composite was determined using the formula shown below.

1-Oath.

Saturated absorption amount (g/g) = − W: Weight of water-absorbing polymer (A) in the absorbent composite (
g) WI: Weight of absorbent composite after liquid absorption (g) No: Weight of filter paper after liquid absorption (g) (2-1) Absorption rate (a) Absorption rate using the apparatus shown in Figure 3 Measure. The upper opening 12 of the billet is plugged, and the measuring table 13 and air port 14 are set at the same height. 0.3 of the liquid-absorbing composite 4 was placed on a glass filter (llh 1 ) 15 with a diameter of 10 mm in the measurement table.
The value of horse defibrinated blood absorbed during the subsequent 20 minutes was expressed as the absorption rate (a).

(2-2) Absorption rate (b) Using the same experimental method as in (2-1) measurement of absorption rate fat, a liquid-absorbing composite with 0.3g of water-absorbing polymer (^) immobilized absorbed in 1 minute. The value of physiological saline was expressed as absorption rate (b).

(3) Absorption power 0.5 cc of horse defibrillation dish or physiological saline was added to 0.05 g of the absorbent composite using a dropper, and the degree of absorption was visually observed and expressed in 4 stages.

(4) Inject pseudo blood Log into the liquid return amount test sample, and add 50g
The liquid that returned when a pressure of /cni was applied was absorbed with filter paper, and this weight was taken as the amount of liquid returned.

(5) Dynamic maximum absorption capacity As shown in FIG. 2(a), the movable female waist model 9,
As shown in fb), after putting on the test sample 11 and putting on shorts, simulated blood was injected through the dripping tube 10 while walking at a speed equivalent to 50 m/min until side leakage occurred. The amount absorbed was measured.

Example-1 Water-absorbing polymer (A): 20g of polyacrylic acid, 100g of ion-exchanged water, and a water-insoluble inorganic substance (
10 g of bentonite as B), and cellulose powder as a water-insoluble hydrophilic fibrous substance (C)
A liquid-absorbing composite was obtained by kneading 10 g of CFII manufactured by Man Co., Ltd. (fiber length ~500) for about 10 minutes using a twin-screw kneader and drying under reduced pressure at 80°C. When this was confirmed using an electron microscope, it was found that bentonite and cellulose powder were immobilized on the surface of the water-absorbing polymer. Also, the bulk specific gravity of this composite is 0.2
It was 4g/cc.

By similar operations, water-absorbing polymer (A), water-insoluble inorganic substance (B), and water-insoluble hydrophilic fibrous substance (C) were prepared in Table-1.
Liquid-absorbing composites were obtained with various modifications as shown in Table 1.

Comparative products include one consisting only of water-absorbing polymer (8), one consisting only of water-absorbing polymer (8) and water-insoluble inorganic substance (B), and one consisting only of water-absorbing polymer (A) and water-insoluble hydrophilic fibrous substance (C). Table 1 also shows the absorption performance of those made of

Using the absorbent composite obtained as described above or a comparative product, a sanitary napkin having the structure shown in FIG. 1(d) was obtained.

In addition, as an absorbent layer, 0.6 g of liquid-absorbent composite and 2 g of cotton pulp were used.
．． 0g, absorbent paper 1.5g, rayon staple cotton 0.3
The surface sheet is made of 65% polyester and 35% polyethylene/polypropylene composite fiber with a basis weight of 20.
A heat-bonded nonwoven fabric of g/n (25 g/m) was used as the waterproof sheet.
μ laminate was used.

The liquid return amount and dynamic maximum absorption amount of the obtained sanitary napkin were measured and shown in Table 1.

As shown in Table 1, it is clear that the absorbent article of the present invention has excellent absorbency for highly viscous liquids such as blood.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing various embodiments of the absorbent article of the present invention, and FIG. 2 is a perspective view of a movable female waist model;
FIG. 3 is a schematic diagram of the apparatus used to measure absorption rates. 1...Liquid-permeable surface material (non-woven fabric) 2...Liquid-impermeable leak-proof material (waterproof sheet) 3...Paper or non-woven fabric 4...Liquid-absorbent composite 5...Crushed pulp or Cellulose powder 6... Mounting paper 7... Crepe paper 8... Rayon staple cotton 9... Movable female waist model 10... Dripping tube 11... Test sample 12... Upper opening of billet 13 ...Measurement stand 14...Air port 15...Glass filter applicant's agent Furuya σ 1st (a) 3 (c) (lx,) (a) Fig. 2 (a) Fig. 3 ( b)

Claims (4)

[Claims] 1. (A) water-absorbing polymer, (B) water-insoluble inorganic substance,
and (C) a liquid-absorbing composite consisting of a water-insoluble hydrophilic fibrous substance, and the composite ratio (weight ratio) is (A):(
B):(C)=100:5-1200:5-1200 An absorbent article containing a liquid-absorbent composite. 2. 2. The absorbent article according to claim 1, wherein the water-absorbing polymer is a polymer of a water-soluble ethylenically unsaturated monomer containing acrylic acid or an acrylate as a main component, or a crosslinked product thereof. 3. The absorbent article according to claim 1 or 2, wherein the absorbent composite is in contact with hydrophilic fibers. 4. The bulk specific gravity of the liquid-absorbing composite is 0.03 to 0.7 g/cc
An absorbent article according to claim 1.