JPH01135350A - Absorbing body - Google Patents

Abstract

PURPOSE:To eliminate the movement and detachment of a polymer, by accumulating absorptive composite elements, each of which has such a structure that heat-meltable fibers extend outwardly from a water-insoluble absorptive polymer particle, into a matlike body and welding the outwardly extending fibers to keep an accumulated state. CONSTITUTION:Each of absorptive composite elements 1 consists of a water- insoluble water absorptive polymer particle 2 and many fibers 3 partially extending outwardly from the interior of the particle 2 and many branch hairs 3b extend from the trunk part 3a of each of the fibers 3. These absorptive composite elements 1 are accumulated into a mat shape and the outwardly extending parts of the fibers 3 are mutually welded to keep a fiber accumulated state.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention [Field of Industrial Application] The present invention relates to an absorbent body for a body fluid absorbent article. More specifically, sanitary napkins and disposable diapers.

This invention relates to absorbers for disposable body fluid absorbing articles such as incontinence pads and breast milk pads.

[Conventional technology and its problems]

Conventionally, absorbent materials are made of a pulverized product of a water-insoluble/water-absorbent resin and a hydrophobic fiber web, some of the fibers are embedded in the resin, and the fibers are made of nylon, acrylic, polyester, polyethylene, or polypropylene. Kaisho 61-62
No. 463, multilayer films consisting of at least two layers,
Japanese Patent Laid-Open No. 62-10490 discloses an absorbent body made of a thermal adhesive composite resin and pulverized pulp, which is obtained by splitting a multilayer film made of a thermoplastic resin whose melting points differ from that of the first layer and the other layer to make short lines.
It is disclosed in No. 3.

In these technologies, the absorber made of the former absorbent material has problems when using a water-insoluble/water-absorbing resin, namely 1.
Migration of water-insoluble and water-absorbing resins that occur in body fluid treatment products
The purpose is to solve problems regarding shedding, diffusivity of the absorbed liquid (lateral diffusion), shape retention after absorption, and dry touch properties. However, since all or part of the conventional absorbent material (pulverized pulp, absorbent paper) is simply replaced with the above-mentioned absorbent material, the movement and shedding of the water-insoluble/water-absorbing resin,
The problem with shape retention when formed into an absorbent body is
Since the absorbent materials are not bonded, it cannot be said that the problem has been solved satisfactorily.

Since the latter absorbent does not contain a water-insoluble/water-absorbing resin, its water absorption is low, even if the water-insoluble/water-absorbing resin is simply mixed therein.

Since the resin and the short wire material are not bonded, movement and falling off of the resin is unavoidable.

The present invention provides an absorbent body that overcomes the aforementioned problems, viz.

The purpose of the present invention is to provide an absorbent body using a water-insoluble water-absorbing resin (polymer), which does not move or fall off of the polymer, has excellent shape retention, and has an improved amount of absorbed liquid.

(2) Structure of the invention [Means for solving the problems] The present invention provides that at least a plurality of heat-fusible fibers are water-insoluble and
In an absorbent body including absorbent composite elements that partially extend from the interior of absorbent polymer particles, the composite elements are accumulated in a mat-like body, the fibers have a trunk and branch ends, and The absorbent body is characterized in that the parts are fused together, and the integrated state is maintained by this fusion.

[Embodiment]

The present invention will be further explained based on embodiments as follows.

In FIG. 1, an absorbent composite element 1 consists of water-insoluble/water-absorbing polymer particles 2 and a plurality of fibers 3, some of which extend from inside the particles. The fibers 3 penetrate the particles 2 or are bent within the particles, and have various bonding modes with the particles.
b is branched.

The polymer particles 2 are, for example, a hydrolyzate of a starch-acrylonitrile graft polymer, a hydrolyzate of a cellulose-acrylonitrile graft copolymer, and 1 usually include:
Those with a mesh size of 8 to 300 are used.

The fiber 3 has thermoplasticity and is, for example, an olefin copolymer such as polyethylene or polypropylene.

Ethylene-vinyl acetate, vinylidene chloride, vinyl chloride, polyamide, and polyester may be used alone or in combination.

The weight ratio of polymer particles 2 and fibers 3 is 10 to 90:9.
The value is preferably 0 to 10, but it is selected within that value depending on the absorbent capacity, elasticity 2 strength, etc. of the absorbent body constructed by integrating the composite element 1 made of the particles and fibers into a mat-like body. If the value is outside these values, such performance cannot be obtained. - On the other hand, the fibers 3 are preferably treated with a Mll coating surfactant in order to improve their leakage properties to body fluids. In addition, the fiber 3 has a fineness of 1 to 6.
0d.

Preferably, the length is 1 to 20 mm, which is
When the fineness is less than 1a and more than 60d, the absorbent body cannot obtain the desired cushioning properties in the former case, and becomes hard in the latter case, and when the length is less than 1m and more than 20am, In the former, the length of extension from the polymer particles 2 is too short to achieve the desired fusion, and in the latter, the fibers are too long and the composite element 1 constituting the absorbent body is too long.
This is because it is difficult to maintain a substantially uniform state of accumulation.

In the second @, a group of composite elements constituting a mat-like absorber (not shown) are integrated. This absorber is 1
00 to 400 g/rd, and the trunks 3a and split ends 3b of the fibers 3 of the composite element 1 are fused at their contact surfaces. The split ends 3b not only increase the strength of the fusion bond between the fibers 3, but also serve as a liquid guide function due to the bridge state between the polymer particles 2 and between the fibers 3.

In FIG. 3, a mixture of a group of composite elements constituting a mat-like absorbent body (not shown) and second fibers 4 is integrated. The fiber 4 has substantially the same material, fineness, and shape as the fiber 3, and has a length of 10 to 130 m. This absorber has a weight of 100 to 500 g/m2, and.

The weight ratio of the composite element 1 and the second fiber 4 is 10 to 9089
0 to 10, and the trunks 3a and split ends 3b of the fibers 3 and 4 are fused at their contact surfaces. This absorber.

The presence of the second fibers 4 complicates the net-like structure in the x, y, and z directions, increases cushioning properties, and significantly improves the liquid guiding function.

In FIG. 4, a group of composite elements constituting a mat-like absorbent body (not shown), a second fiber 4, and a cotton-like pulp 5, which is preferably shorter than the fibers 3 and 4 of the element, are shown. A mixture is accumulated. This absorber has a 100 to 700
g/try, and composite element 1, second fiber 4
, the weight ratio of flocculent pulp 5 is 10-90:90-to
: to~80, fibers 3, 4 trunks 3a, 4
a. As mentioned above, the split ends 3b and 4b are fused at their contact surfaces, and the presence of the split ends 3b and 4b forms a complex net-like structure in the XZY directions. By.

The flocculent pulp 5 is surrounded to prevent the pulp from moving or falling off.

The cotton-like pulp 5 is mixed to further improve the liquid conduction function in the absorbent body, but if it is less than 10% by weight, the desired effect cannot be obtained, and if it is more than 90% by weight, the composite The weight percentage of the element 1 has to be lower than desired, and the desired absorption capacity cannot be secured.

Note that the composite element 1 is, for example, disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 61-624.
As disclosed in No. 63, a polymer is swollen by absorbing water, the polymer is mixed with fibers,
Obtained by drying and grinding.

Furthermore, as described above, the fibers 3 have split ends 3b branching from the trunk 3a;

As disclosed in JP-A No. 62-104903, a multilayer resin film having different melting points is stretched after slitting, or slit after stretching, and then split with a rotating needle roll to shorten the film. The fibers 3 obtained in this way are preferably those obtained by fiberization,
In addition to having split ends 3b, it has a flat cross section and is a composite of resins with different melting points, so the heat melting surface is large, and the high melting point resin will not melt when fused at a low melting point resin temperature. , fully performs the supporting function of the polymer particles 2, and the composite element 1
This is because when the absorbent body is formed into a matte state, a large number of voids are generated on the surface and inside of the absorbent body, resulting in rich cushioning properties and improved strength. but.

Even if a film made of a single resin is made into split fibers as described above, fibers 3 having split ends 3b and a flat cross section can be obtained. ) etc. can compensate to some extent the disadvantages of not being a conjugate fiber, so it does not necessarily have to be a conjugate fiber.

〔Example〕

Examples and comparative examples are shown in the attached table.

Polymer particles 2, fibers 3, and 2nd used in Examples and Comparative Examples
The fiber 4 is as follows.

Polymer particles 2 are made of acrylic acid polymer (Sunwet manufactured by Sanyo Chemical Co., Ltd.) and have a pore size of 10-16 mesh.

The fiber 3 is a composite of polypropylene and polyethylene, and has a fiber length of 1 to 5 cm, a fineness of 12, and a number of split ends 3b of approximately 9.
/ 1 cm.

The second fiber 4 is a composite of polypropylene and polyethylene, has a fiber length of 20 to 50 cm, a fineness of 12, and a number of split ends 4b of about 7/1 (!l).

Fiber 3.4 was spray treated with the surfactant Noni Keiru 100 (Sanyo Kasei - 111).

The absorbent material was prepared by heating a predetermined amount of composite element 1, a mixture of composite element 1 and fiber 3, a mixture of composite element 1, second fiber 4, and cotton pulp 5 at a pressure of 0.7 g/aJ and a treatment temperature of 136°C. , obtained by processing at ITf of 16 minutes.

Each side of the table indicates:

Example 1 It is shown that the composite element preferably has a weight of 100 to 400 g/m2. If it is less than 100 g/rd, the amount of compression recovery is poor and there is no strength. If it exceeds 400g/rd, the absorber is hard.

Example 2 The ratio of polymer particles and their fibers in a composite element is 1
0 to 90: indicates that a weight ratio of 90 to 10 is preferable; if the proportion of polymer particles is less than 10% by weight, the water absorption capacity when pressurized is poor, resulting in a relatively thick absorbent body. .

If the proportion of polymer particles 2 exceeds 90% by weight, DRY
The compression recovery rate at -11ET is poor and there is no strength.

Example 3 When the absorbent body consists of a composite element and a second fiber,
It is shown that the weight ratio of each of them is preferably lθ to 90:90-10.

If the proportion of the composite element is less than 10% by weight, the absorption capacity,
Poor water retention. When the proportion of the composite element exceeds 90% by weight, the compression recovery rate at WB2 is poor and there is no strength.

Example 4 When the absorbent body is composed of an absorbent material and a second fiber aggregate, it is preferably 100 to 500 g/rrr. If the absorbent body is less than 100 g/rrr,
Poor compression recovery at WB2, absorber is 500g/r
If it exceeds d, it will be thick and unsuitable as an absorbent material for sanitary materials.

Example 5 When the absorbent body consists of an absorbent material, a second fibrous material, and pulverized pulp (when pulverized pulp is added to Example 3), it is preferable that the weight ratio of the pulverized pulp is 10 to 80% by weight. shows. If the pulverized pulp is 10% by weight, the effect of using the pulverized pulp (increased absorption rate) cannot be obtained.

Example 6 The absorbent body is composed of an absorbent material, a second fiber, and pulverized pulp, and the absorbent body is preferably 100 g/n? If it is less than
If the compressive elasticity is weak and the absorber exceeds 700g1rrr, the absorber is too thick.

Example 7 Comparative Example According to JP-A-62-104903, the compression recovery amount, compression recovery rate, absorption capacity, and absorption capacity during pressurization are poor.

The performance tests in the table were conducted as follows.

[Compression recovery amount]

Bend the test piece 10 csa x 10 cm 180',
A load of g/al is applied for 3 minutes. Measure the recovery angle of the test piece after 1 minute of leaving the load on.

In addition, for the measurement at WB2, physiological saline equivalent to 5% of the test piece was absorbed, and a similar test was conducted 15 minutes later.

[Compression recovery rate]

For a test piece of 10 cm x 10 mm, V x : 0-5 g/cxl (i') Initial volume under load (mm) V x : Compression volume (mm) when a load of 50 g/aJ is applied for 3 minutes ■, : Volume (W) when a load of 0.5 g/ad is applied for 3 minutes after unloading, V, -V2 For measurements at WB2, use physiological saline equivalent to 5% of the basis weight of the test piece. A similar test was conducted after 15 minutes of absorption.

[Tensile strength]

Five test pieces with a width of 25+a and a length of 150 m are taken.

Using a constant speed extension type tensile tester (Shimadzu Corporation), the test piece was pulled at a grip interval of 100 mm and a tensile speed of 10 (1 m/sin).

The maximum strength and elongation (kg) was measured.

[Absorption capacity/Absorption capacity when pressurized]

Fold a mesh (NBC Kogyo @NNo250HD) with a width of 120 mm and a length of 240 m in the length direction so that the opposite ends overlap, and seal the two ends outside the folded piece with a seal width of 51 mm or less to create an absorbent coated bag. , and its weight is V. Indicated by

A test piece was cut into a size of 100 mm x 1100 r, inserted into an unsealed piece of the absorbent coating bag, and the piece was sealed to prepare a test piece, and the following measurements were performed.

■: Indicates the weight of the test specimen.

v2: The weight after immersing the test specimen in physiological saline (NaCl O, 9%) for 10 minutes and leaving it on a wire mesh for 5 minutes is shown.

(3) The test specimen is placed on a two-wire mesh (5 meshes), and a weight of 3.5 kg/1010 x 1 t) is placed on top of it.

(2): Indicates the weight after a weight was placed on the test specimen for 20 minutes.

V, -V.

Vl-V.

(3) Effect of the invention According to the present invention, t! The i-collection body includes an absorbent composite element group in which at least a plurality of heat-fusible fibers partially extend from inside polymer particles, and the composite element group is integrated into a mat-like body, and the fibers are has a trunk and split ends, which are fused to each other to maintain the integrated state, so that the composite element is prevented from moving or falling off, and the absorbent body has excellent shape retention. Moreover, since a three-dimensional net-like structure is formed by the fiber trunks and split ends, the cushioning properties of the absorbent body, an increase in liquid absorption capacity, and liquid conductivity or liquid diffusion/absorption properties are improved. Therefore, it is suitable for use as an absorber in a body fluid absorbent article.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a model diagram of an absorbent composite element constituting the absorber according to the present invention, FIG. 2 is a model diagram of the integrated state of the composite element, and FIG. 3 is a model diagram of the composite element and FIG. 4 is a model diagram of an integrated state resulting from mixing with the second fiber and FIG. 4 is a model diagram of an integrated state resulting from mixing the composite element and the second fiber with a cotton-like bulb. 1... Composite element 2... Polymer particles 3
...Fiber 4...Second fiber 3a,
4a... Trunk 3b, 4b... Branch hair 5
...cotton pulp

Claims (11)

[Claims] (1) In an absorbent body including an absorbent composite element in which at least a plurality of thermofusible fibers partially extend from inside water-insoluble absorbent polymer particles, the composite element is accumulated in a mat-like body, and the fibers are The absorbent body has a trunk and split ends, the extending portions of the fibers are fused to each other, and the accumulated state is maintained by this fusion. (2) The absorbent body according to claim 1, wherein the thermofusible fiber is made of a single polymer or a composite of multiple polymers having different melting points. (3) the absorbent body is made of a mixture of the composite element and a second fiber having the same physical properties as the fiber of the composite element,
The absorbent body according to claim 1, wherein the second fibers of the fiber extension portion of the composite element are fused to each other. (4) The absorbent body is made of a mixture of the composite element, second fibers having the same physical properties as the fibers of the composite element, and cotton-like pulp that is shorter than both of the fibers, and The absorbent body according to claim 1, wherein the fiber extending portion and the second fiber are fused to each other. (5) The element has a weight ratio of the polymer and the fibers partially exposed from inside the particles of 10 to 90:90.
10. The absorbent body according to claim 1, which has a molecular weight of 10 to 10. (6) The fiber of the composite element and the second fiber are a single substance or a composite selected from olefin copolymer, ethylene-vinyl acetate, vinylidene chloride, vinyl chloride, polyamide, and polyester. The absorbent body according to item 1. (7) The absorbent body according to claim 1, wherein the fibers of the composite element and the second fibers are treated with a surfactant. (8) The absorbent body according to claim 1, wherein the fibers of the composite element and the second fibers have a fineness of 1 to 60 d. (9) The absorbent body according to claim 1, wherein the fibers of the composite element and the second fibers have lengths of 1 to 20 mm and 10 to 130 mm, respectively. (10) The absorber according to claim 1, wherein the composite element has a weight of 100 to 400 g/m^2. (11) The absorber has a weight of 100 to 500 g/m^2, and the weight ratio of the composite element to the second fiber is 10 to 90.
:90-10. (12) A patent claim in which the absorber has a weight of 100 to 700 g/m^2, and the weight ratio of the composite element, the second fiber, and the cotton pulp is 10 to 90:90 to 10:10 to 80. The absorber according to item 4.