JP2847248B2 - Odor and water absorbing sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a disposable diaper, a pet excrement disposal material, a sealing material, a packing material, an odor absorbing and water absorbing material of an air duct, a coating protective material for various containers, and a sweat absorbing equipment. The present invention relates to an odor absorbing and water absorbing sheet which can be used for a wide range of applications.

[Prior Art] Various studies have been made on removing moisture and odorous substances, and water-absorbing paper, cotton-like pulp, and highly water-absorbing resin are often used as water-absorbing materials.

On the other hand, in recent years, attention has been paid to the odor absorbing and water absorbing properties of magnesium silicate-containing clay minerals such as sepiolite and attapulgite. Looking at the crystal structure of the magnesium silicate-containing clay mineral, it has a large number of hydroxyl groups on its surface, and is a porous body with pores, about 300 m
^It has a specific surface area of ² / g. For this reason, it has been proposed to be used in combination with a conventional water-absorbing material as a water-absorbing material or an adsorbent, because it has a high water-absorbing property and a high adsorptivity to various substances.

For example, Japanese Patent Application Laid-Open No. 61-58657 discloses a water-absorbing material in which a highly water-absorbent resin is mixed with fine attapulgite paper to increase the diffusion of water and enhance the water-absorbing effect. Also,
JP-A-63-23662 discloses an absorbent article having a high water-absorbing resin mixed with an ion exchanger such as sepiolite, zeolite, and ion-exchange resin to improve water absorption and suppress odor. It has been disclosed.

[Problems to be Solved by the Invention] However, in the above-described conventional one, a superabsorbent resin and a magnesium silicate-containing clay mineral such as sepiolite are uniformly mixed to form a water-absorbing layer. Although the improvement effect of the silicate is seen to some extent, the super-water-absorbent resin that has swollen by water absorbs the magnesium silicate-containing clay mineral, and cannot sufficiently exhibit the inherent water-absorbing and odor-absorbing effects of the magnesium silicate-containing clay mineral. There was a problem.

In addition, when using magnesium silicate-containing clay minerals, since fine particles of 10 μm or less were used in the past, dust was generated during handling and the manufacturing machine was damaged, or dust was scattered in the air and workers There was a problem in safety, such as the possibility of entering the respiratory tract. Further, the magnesium silicate-containing clay mineral is often used in a powder form, and there is a problem that the magnesium silicate-containing clay mineral moves and shifts in the sheet even after being processed into a sheet.

Accordingly, an object of the present invention is to provide an odor absorbing and water absorbing sheet which improves the absorption performance of odor substances mainly composed of water and ammonia odor and exhibits excellent properties.

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above-mentioned circumstances, and as a result, a layer composed of particles of a magnesium silicate-containing clay mineral and a highly water absorbent resin layer It has been found that a sheet exhibiting excellent odor and water absorption properties can be obtained by laminating the fibers so as to be independent layers with a fibrous absorbent layer made of pulp interposed therebetween.

In the present invention, the magnesium silicate-containing clay mineral is a clay mineral containing magnesium silicate as a main component, is composed of an aggregate of fibrous or acicular microcrystals, and has a highly reactive hydroxyl group on its surface. Further, the magnesium silicate-containing clay mineral is water-containing and has a property of absorbing a large amount of water itself.

Specifically, sepiolite (Sepiolite) mainly containing hydrous magnesium silicate, Palygorskite (Palygorskite) mainly containing hydrous magnesium aluminum silicate, Attapulgite
And the like. Also known as the Mountain Cork
tain cork), Mountain leather (Mountain leather),
It is also called mountain wood and other types of sepiolite in Japan.

When the magnesium silicate-containing clay mineral is applied to the present invention, fine particles obtained by finely pulverizing raw stones mined in a mine can be used as they are. The particle size of the pulverized magnesium silicate-containing clay mineral is usually 20 mesh under, 200
It is preferable that the mesh is over, that is, the range is 74 to 840 μm. More preferably 42 mesh under, 100
The mesh is over, that is, the range is 149 to 350 μm.

By removing the under 200 mesh, dust can be prevented from being generated during sheet production, safety is improved, and failure due to powder adhesion to the rotating part of the sheet forming machine as a manufacturing machine can be suppressed. Furthermore, after shaping into a sate shape, it is possible to prevent the magnesium silicate-containing clay mineral particles from falling off the fibrous absorbent layer and causing the magnesium silicate-containing clay mineral particles to be offset in the sheet. In addition, when the particle size is increased, when the particles are dispersed on the fibrous absorbent material layer, they become entangled with the fibers, and are easily fixed in the sheet.

Also, by removing the 20 mesh over, the contact area of the magnesium silicate-containing clay mineral, that is, the effective adsorption area can be increased, or the cushioning property and the feel of the sheet after forming into a sheet shape can be improved. Hold.

In the present invention, the superabsorbent resin is a resin having the ability to absorb and retain water approximately 60 to 150 times the weight of the resin, and specific examples of such a resin include cross-linked polyacrylic acid. Sodium, vinyl acetate-acrylate copolymer saponified product, vinyl acetate-methyl maleate copolymer saponified product, isobutylene-methyl maleic anhydride methyl copolymer crosslinked product, starch-acrylonitrile graft copolymer saponified product, Starch-Acrylic acid graft polymer, polysaccharide-Acrylic acid graft polymer, CMC cross-linked to cellulose and monochloroacetic acid reactant, CMC of cupra rayon long fiber, Cross-linked product of polyvinyl alcohol, Polyethylene oxide Crosslinked products and the like can be mentioned. These resins, besides powder, fibrous,
Any shape such as a sheet shape can be used. When a powdery material is used, its particle size may be approximately the same as the above-mentioned magnesium silicate-containing clay mineral particles.

In the present invention, cotton-like pulp is used as the fibrous absorbent layer. The flocculent pulp is a pulp obtained by chemically treating groundwood and made into a flocculent shape by a crusher, and is, for example, a kraft pulp treated with an acidic solution or a sulfite pulp treated with an alkaline solution.

In the present invention, the particles of the magnesium silicate-containing clay mineral and the superabsorbent resin are laminated with a fibrous absorbent layer made of cotton-like pulp interposed therebetween so that each forms an independent layer. There is a need. By arranging each layer of the magnesium silicate-containing clay mineral particle layer and the high water-absorbing resin layer in separate layers, the water-absorbing resin swells and the super-water-absorbing resin wraps around the magnesium silicate-containing clay mineral particles. Therefore, the odor absorbing function of the magnesium silicate-containing clay mineral can be sufficiently exhibited.

The amount of the magnesium silicate-containing clay mineral and the superabsorbent resin constituting the odor-absorbing and water-absorbing layer is 40% based on the total weight of the magnesium silicate-containing clay mineral and the superabsorbent resin. It is preferable that the content of the superabsorbent resin layer is 25 to 60% by weight. It is possible to make the magnesium silicate-containing clay mineral layer more than 75% by weight, but the sheet formability is reduced, and if it is less than 40% by weight, the odor absorbing effect is reduced. The amount of the fibrous absorbent used is not particularly limited and can be appropriately selected depending on the purpose and situation.

Specifically, when used as a disposable diaper, a child 50cc
-It is required to have the ability to absorb 2 to 3 times of 250cc of adult, while the water absorption and retention capacity of urine is 40g of super absorbent resin 1g, clay mineral containing magnesium silicate 1g
Is 1 g, and 1 g of fibrous absorbent is 10 g. Accordingly, the amount of the superabsorbent resin and the magnesium silicate-containing clay mineral in the range of about 5 to 20 g per one diaper may be set so as to satisfy the above blending ratio.

When producing the odor absorbing and water absorbing sheet of the present invention,
If necessary, a fibrous absorbent or other water-absorbing material, a waterproof sheet, or the like is laminated on the above-described structure, and the end faces are pressed to form a sheet. Specifically, for example, a cotton-like pulp layer, a superabsorbent resin layer, a cotton-like pulp layer, a magnesium silicate-containing clay mineral particle layer, and a cotton-like pulp layer are sequentially laminated on the upper layer of a waterproof sheet made of a polyethylene film. After the liquid permeable nonwoven fabric is disposed on the uppermost layer, the sheet is formed by applying pressure using an embossing roll and pressing the end face by heat sealing or the like.

The layer of the magnesium silicate-containing clay mineral and the superabsorbent resin may be formed by uniformly dispersing these particles on a flocculent pulp layer. Movement is suppressed.

The configuration of the seat is not limited to this,
The layer of the magnesium silicate-containing clay mineral and the layer of the superabsorbent resin are separated by the fibrous absorbent composed of the cotton-like pulp layer,
If the layers are arranged as independent layers, the effect of the present invention can be sufficiently exhibited even if the layers are exchanged up and down or the number of layers is increased. For example, since the magnesium silicate-containing clay mineral is used in the form of particles, it is difficult to fix the clay mineral in the sheet as the amount of use increases. This limit is about 150-1
If it exceeds 80 g / m ^2, it is preferable to form a magnesium silicate-containing clay mineral layer in multiple layers and to provide a fibrous absorbent layer composed of a cotton-like pulp layer between each layer.

In order to further enhance the deodorizing effect, another deodorant such as a flavonoid can be appropriately mixed into the magnesium silicate-containing clay mineral layer or the superabsorbent resin layer.
Further, if necessary, a fragrance, a preservative, a bactericide, an antioxidant, a coloring agent and the like can be mixed and used.

[Action] The excellent odor absorbing property of the magnesium silicate-containing clay mineral is largely contributed by the porous property due to the crystal structure and the hydroxyl group on the surface having high reactivity. In other words, malodorous substances such as ammonia are trapped by a bonding force mainly composed of hydroxyl groups existing on the surface and hydrogen bonds, or by a physicochemical bonding force at an active point centered on a lattice defect inside the porous body. It is believed to be trapped. In addition, since magnesium silicate-containing clay minerals have a cation exchange reactivity characteristic of clay minerals, it is thought that cationic odor substances such as ammonium ions are absorbed in the liquid phase even after absorbing water. Can be

And, in the present invention, since the magnesium silicate-containing clay mineral and the superabsorbent resin are formed as independent layers, the superabsorbent resin swelled by absorbing water wraps the magnesium silicate-containing clay mineral particles. Therefore, the above-mentioned properties of the magnesium silicate-containing clay mineral can be sufficiently exhibited. In addition, the fibrous absorbent layer made of cotton pulp separates each of these layers,
Promotes the diffusion of absorbed moisture in the vertical or horizontal direction.

[Examples] Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 As a magnesium silicate-containing clay mineral, raw Turkish sepiolite was coarsely pulverized with a jaw crusher, then further finely pulverized with a pulperizer, using a vibrating sieve.
Fine particles excluding the 20 mesh over product and the 200 mesh under product were obtained (particle size: 74 to 840 μm). Also, as the super absorbent resin, Acrylic CA which is an acrylic resin
(Nippon Shokubai Chemical Co., Ltd., trade name, specific gravity 0.62, particle size 74 ~
840 μm).

Using these, polyethylene film (thickness 10μ)
m, first layer), on top of floc pulp (65 g / m ² , second layer),
Super absorbent resin (29g / m ² , 3rd layer), cotton-like pulp (65g /
m ² , fourth layer), sepiolite (29 g / m ² , fifth layer), flocculent pulp (65 g / m ² , sixth layer), racon nonwoven fabric (15 g / m ² ,
(Seventh layer) were sequentially laminated to produce a sheet.

As shown in the figure, a sheet-forming machine (manufactured by Zumiko Co., Ltd.) was used to make the sheet, and as shown in FIG. After uniformly spraying and pressurizing, a layer of a highly water-absorbent resin was formed on the upper surface, and a cotton-like pulp and water-absorbing paper were further guided thereon. This was heated and pressurized to 130 to 150 ° C. to perform embossing press working, and then a nonwoven fabric was laminated on the surface on the sepiolite side and a polyethylene film was laminated on the surface on the superabsorbent resin side to obtain a sheet having a thickness of 5 mm.

The obtained sheet was subjected to the following ammonia absorption test and physiological saline absorption test. In the ammonia absorption test, the sheet is 70cm long and 30cm wide (2100cm ^{2 in} area)
And placed in an acrylic box-shaped container having an internal volume of 60, and containing a saline solution of ammonia ( ₄ ml of 28% NH ₄ OH, 8 g of NaCl containing 8 g).
30 ml of water solution) into a sheet, seal the box-shaped container
After standing for 30 minutes, the residual ammonia concentration was measured using a Kitagawa type detector tube. The results are shown in Table 1.

In the physiological saline absorption test, the sheet was 6.35 c long.
m, cut into 6.3 cm width (area 40 cm ² ), stapled so as not to loosen the ends, dried at 105 ° C for 2 hours, weighed (excluding stapler needle weight),
It was immersed in 100 ml of water at 20 ° C. for 3 minutes, sandwiched between plastic plates for sweat test (11.5 cm × 6.3 cm), and pressed with a 2 kg weight for 10 seconds. Thereafter, the weight was measured and one sheet material (area 2100
The water retention per cm ² ) was calculated. The results are shown in Table 1.

Further, a finger was pressed from the surface of the sheet material for the purpose of testing the usability, and the texture (roughness) was evaluated. Further, the sheet was placed in a container of a vibrating sieve and vibrated for 5 minutes with a vibrating sieve, and then the sheet was taken out, and it was examined whether sepiolite had leaked to the sheet surface. Table 2 shows the test results of the texture and the movement of sepiolite in the sheet.

Example 2,3 23 g / m ² the amount of sepiolite layer, except that the amount of the superabsorbent polymer layer was 34g / m ² Example 1 Example a disk produced a sheet in the same manner as 2 And Similarly,
Example 3 in which the compounding amount of the sepiolite layer was 42 g / m ² and the compounding amount of the superabsorbent resin layer was 15 g / m ² , was used for the ammonia absorption test and the physiological saline in the same manner as in Example 1. A water absorption test was performed. The results are shown in Table 1.

Comparative Example 1 A mixture in which the fine-grained sepiolite used in Example 1 and the superabsorbent resin were mixed in equal amounts in advance was prepared, and this was used as the absorbing layer. That is, the third and fifth layers in the sheet of Example 1 were replaced with layers of the above-described mixture, and a water-absorbing paper was sandwiched above and below these third and fifth layers, respectively. A sheet was prepared by the method. The same test as in Example 1 was performed, and the results are shown in Table 1.

Example 4 A sheet was prepared in the same manner as in Example 1 except that the particle size of the sepiolite and the superabsorbent resin was changed to 42 mesh under and 100 mesh over, that is, 149 to 350 μm. . The scattering of dust in the processing line, especially in the pressing step was small and good.
Table 1 and Table 2 also show the results of a test performed on the obtained sheet in the same manner as in Example 1.

Example 5 Particle size of sepiolite and superabsorbent resin was 42 mesh under and 100 mesh over, that is, 149 to 350 μm
A sheet was produced in the same manner as in Example 1, except that the blending amount of the sepiolite layer was 50 g / m ² and the blending amount of the superabsorbent resin layer was 70 g / m ² . Table 1 also shows the results of the test performed in the same manner as in Example 1.

Comparative Examples 2 to 4 Comparative Example 2 was obtained by removing only the sepiolite layer (fifth layer) from the sheet having the configuration of Example 1, and Comparative Example 3 was obtained by removing only the superabsorbent resin layer (third layer). Comparative Example 4 excluding any of the, the sepiolite layer and the superabsorbent resin layer
Was prepared in the same manner. Table 1 also shows the results of the same test for each.

Comparative Example 5 Turkish raw sepiolite was roughly pulverized and then further finely pulverized with a pulperizer and used without classification. When the particle size of the crushed sepiolite was examined,
25% by weight mesh over product, 1 under 200 mesh product
5% by weight was contained.

A sheet was prepared in the same manner as in the sheet of Example 1 except that the unclassified sepiolite was used as the sepiolite layer (fifth layer). A test for the texture of the obtained sheet and the movement of sepiolite in the sheet was conducted in the same manner as in Example 1, and the results are shown in Table 2.

As is clear from Table 2, the sheet of Comparative Example 5 had a rough feel when pressed with a finger, and had a poor texture. Further, when vibration is applied to the sheet, it is recognized that fine particles of sepiolite have moved to the back side of the polyethylene film, which is problematic in terms of quality.

[Effects of the Invention] As described above, according to the present invention, particles of a magnesium silicate-containing clay mineral and a superabsorbent resin are laminated with a fibrous absorbent layer made of cotton-like pulp interposed therebetween. Formed an independent layer, so that the excellent odor absorbing and water absorbing properties of the magnesium silicate-containing clay mineral can be sufficiently exhibited, and the odor absorbing and water absorbing sheet for removing the moisture accompanied by the bad odor. As an excellent effect.

Further, by setting the particle size of the magnesium silicate-containing clay mineral within a predetermined range, the deviation of the magnesium silicate-containing clay mineral particles in the sheet is prevented, and the cushioning property and the feel of the skin of the sheet are improved. In addition to suppressing the failure due to powder adhesion on the rotating part of the sheeting machine,
Dust scattering can be suppressed, and safety is improved.

Further, in the production of the sheet, there is no need for a step of mixing the magnesium silicate-containing clay mineral with the superabsorbent resin, so that there is an advantage that productivity is improved.

[Brief description of the drawings]

The figure is a diagram for explaining the manufacturing process of the odor absorbing and water absorbing sheet in the example of the present invention.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ryusuke Tsuji 41-41, Yokomichi, Chuchu-cho, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central R & D Laboratories Co., Ltd. (72) Inventor, Hiroaki Hayashi 41 No. 1 Yokomichi Inside Toyota Central Research Laboratory Co., Ltd. (72) Inventor Takeo Takeo 4-7-23 Meieki Station, Nakamura-ku, Nagoya City, Aichi Prefecture Inside Toyota Tsusho Co., Ltd. (72) Inventor Takashi Chichizawa Inocho, Agawa-gun, Kochi Prefecture 4003 Chikazawa Paper Mill Co., Ltd. (56) References JP-A-62-243805 (JP, A) JP-A-61-58657 (JP, A) JP-A-56-31425 (JP, A) JP-A-54-132389 (JP, A) JP-A-63-122452 (JP, A) JP-A-1-142404 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) A41B 13/00-13 / 08

Claims (3)

(57) [Claims] 1. A layer comprising particles of a magnesium silicate-containing clay mineral and a superabsorbent resin layer laminated so as to be mutually independent layers with a fibrous absorbent layer made of cotton-like pulp interposed therebetween. An odor absorbing and water absorbing sheet characterized by the following. 2. The amount of the magnesium silicate-containing clay mineral layer is 40 to 75% by weight based on the total weight of the magnesium silicate-containing clay mineral layer and the high-absorbent resin layer, and the amount of the high-absorbent resin layer is The odor-absorbing and water-absorbing sheet according to claim 1, wherein the content is 25 to 60% by weight. 3. The odor absorbing and water absorbing sheet according to claim 1, wherein the particle size of the magnesium silicate-containing clay mineral is in the range of 74 to 840 μm.