JP2916068B2 - Method for producing functional nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a functional nonwoven fabric carrying various functional particles.

[0002]

2. Description of the Related Art Focusing on the fact that calcium phosphate compounds have an adsorbing effect on various substances and animal and plant cells, a functional paper containing calcium phosphate compound particles has recently been proposed. However, this functional paper
In addition to poor air permeability, flexibility, tear strength, etc., there was also a problem that the calcium phosphate particles carried on the paper pulp easily fall off during handling, and the paper cannot be washed because it is dissolved by washing with water. .

[0003] In order to improve the above problems, the present inventors have proposed a functional nonwoven fabric using a water-soluble binder.
This functional nonwoven fabric is sufficiently improved in performance such as air permeability, flexibility, and tear strength, but has a problem that calcium phosphate particles are liable to fall off by washing with water. Therefore, it can only be used for disposable purposes. Further, since the water-soluble binder covers the surface of the calcium phosphate particles, the adsorption / deodorization performance thereof is not sufficiently exhibited, and as a result, it is necessary to use a large number of calcium phosphate particles, resulting in an increase in cost.

[0004]

The object of the present invention is to solve the above-mentioned disadvantages of the prior art and to carry not only calcium phosphate compound particles but also various particles having various functions as efficiently as possible. An object of the present invention is to provide a method for producing a functional nonwoven fabric that can exhibit excellent performance without falling off by a water washing treatment or the like.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a part or all of the raw material fibers of a nonwoven fabric is made of a thermoplastic polymer fiber, and after carrying functional particles, heat treatment is performed at a temperature higher than the softening point of the thermoplastic polymer fiber. Thus, the above-mentioned object is achieved by softening the fibers and fixing the functional particles to the tacky fibers.

That is, there are two methods for producing a functional nonwoven fabric according to the present invention. A nonwoven fabric in which at least a part of raw material fibers is made of thermoplastic polymer fibers is impregnated or coated with an aqueous dispersion containing functional particles, The functional particles are fixed by the thermoplastic polymer fiber which has been heat-treated at a temperature equal to or higher than the softening point of the thermoplastic polymer fiber and becomes sticky at the contact portion, and the surface of the remaining particles is exposed. And a raw material fiber comprising at least a part of a thermoplastic polymer fiber and a particle size of 0.01 to 200 μm
Non-woven fabric is manufactured by a papermaking technique using an aqueous dispersion containing the functional particles of m, and the functional particles are formed by the thermoplastic polymer fiber which is heat-treated at a temperature equal to or higher than the softening point of the thermoplastic polymer fiber and becomes tacky. Is fixed at the contact portion and the surface of the remaining particles is exposed.

In the present invention, the above method is a method using a nonwoven fabric previously produced by a dry method or a wet method,
Is a method in which functional particles and, if necessary, a surfactant are added to a slurry of raw fibers when a nonwoven fabric is produced by a wet method.

[0008] In any of the methods, at least a part of the raw fibers used in the nonwoven fabric must be thermoplastic polymer fibers. The thermoplastic polymer fiber is preferably contained at 10% by weight or more of the raw material fiber, more preferably at 20% by weight or more. The nonwoven fabric may be made entirely of thermoplastic polymer fibers.
As the thermoplastic polymer fibers, for example, polyethylene fibers, polyolefin fibers such as polypropylene fibers,
Examples thereof include polyamide fibers such as 6,6-nylon and the like, vinyl fibers, acrylic fibers, polyurethane fibers, polyester fibers, and the like, and these can be used alone or in combination. Other raw fibers include natural fibers such as cotton and wool, artificial fibers such as rayon, and mixtures thereof. In addition, the fiber length and fineness of the fibers used and the thickness of the nonwoven fabric can be appropriately selected according to the use and the like.

The functional particles used in the present invention are not particularly limited, and various types can be used. For example, a calcium phosphate compound having a Ca / P ratio of 1.0 to 2.0, titanium dioxide, Activated carbon, zeolites, molecular sieves, inorganic deodorants, inorganic antibacterial agents, and mixtures thereof are exemplified.

[0010] Calcium phosphate compounds are substances that have an adsorbing effect on malodorous components in gases, various substances in liquids, and animal and plant cells, and are used as deodorants, adsorbents, cell separating agents, antibacterial agents, and the like. You. Specific examples of the compound include various apatites such as hydroxyapatite and fluorapatite, tricalcium phosphate, tetracalcium phosphate, calcium hydrogen phosphate and the like. These compounds can be produced by a method known per se, and can be used alone or as a mixture of two or more.

[0011] Titanium dioxide is a substance that exhibits an antibacterial action when returning to a ground state after being excited by ultraviolet light and visible light. Activated carbon is known to have an adsorbing effect on a wide range of substances.
It is used as a decolorizing agent, a deodorant, a catalyst carrier, and the like, and zeolite and molecular sieve are used as an adsorbent. Further, examples of the inorganic deodorant include Kayamax (trade name: manufactured by Nippon Kayaku Co., Ltd.) and Dime Shoe (trade name: manufactured by Dainichi Seika Kogyo Co., Ltd.). For example, apatite supporting silver ions or the like (for example, apatite commercially available from Sangi Co., Ltd. under the trade name APASIDER) can be used.

In the present invention, the functional particles are powder,
It may be in the form of granules or porous granules, the particle size of which
Those having a size of 0.01 to 200 μm are used. Particle size 0.0
If it is less than 1 μm, the particles are likely to aggregate, making it difficult to uniformly disperse the particles in water. On the other hand, when the particle size exceeds 200 μm, the finished nonwoven fabric has a poor touch and tends to have reduced functions such as adsorption ability. Also, the specific surface area is
It is preferable that the particles have a particle size of 0.1 m ² / g or more. When the specific surface area is less than 0.1 m ² / g, functions such as an adsorption effect become insufficient.

When a nonwoven fabric is produced by the above method, it is more preferable to use functional particles having a particle size of 1 to 30 μm . If the particle size is smaller than 1 μm, it will fall from the net of the paper machine together with water during papermaking, and if it exceeds 30 μm, it will be too heavy and difficult to disperse uniformly.

The powder or granules of the functional particles as described above can be produced by any known method. As an example, a method for producing porous granules of a calcium phosphate compound will be described below. First, crystal particles of a calcium phosphate-based compound wet-synthesized by a known method are used as raw material particles, and a slurry in which the raw material particles are suspended is granulated into secondary particles by direct spray drying or the like, or a viscosity modifier is added to the slurry. Additives such as organic compound particles or fibers that disappear by heating are added and granulated into secondary particles by spray drying or the like. The secondary particles themselves are porous particles, and the secondary particles can be used as a raw material as they are. If a material having a high porosity is preferable, a porous granule is produced by the following method. The secondary particles are suspended again in a slurry state and wet-molded, or formed into a block by dry molding or the like under pressure. At this time, an organic compound for dissipating and forming pores during the firing may be added. Even without the addition, the pore size can be controlled by adjusting other conditions such as the firing temperature. The obtained block body is fired in a temperature range of 500C to 1300C. If the firing temperature is lower than 500 ° C., heat disappearance of the organic compound and sintering of the block are not sufficiently performed. In addition, firing is performed at 1300 ° C.
If the heat treatment is performed at a higher temperature than the above, the sintered body may be excessively densified, or calcium phosphate may be decomposed. After the thus baked block is pulverized and classified, granules having a required particle size can be obtained. The pore size of the granules can be adjusted by appropriately adjusting the size of the crystal particles in the raw material slurry for secondary particle granulation, the viscosity of the slurry, additives, and the like.

The amount of the functional particles carried by the nonwoven fabric varies depending on the type and use of the functional particles, and can be appropriately selected in a wide range. In general, the amount of the calcium phosphate compound particles is 1 to 65% by weight. Preferably 5 to 4
More preferably, it is 0% by weight. If it is less than 1% by weight,
If the effect of the calcium phosphate compound is not exhibited and exceeds 65% by weight, the particles scattered during handling and the like increase. In addition, in this specification, a loading rate is a percentage based on the functional nonwoven fabric of a finished product.

When the method of the present invention is carried out, a surfactant may be further added in order to improve and stabilize the dispersion of the functional particles or the particles and the raw material fibers. The surfactant is not particularly limited, and various anionic, amphoteric, and nonionic surfactants can be used, and among these, anionic surfactants are preferable.
Examples of the anionic dispersant include carboxylate, sulfonate, sulfate, phosphate, phosphonate, and the like. Of these, sulfate salts such as sodium dodecyl sulfate are particularly preferred. The surfactant is preferably used in an amount of 15% by weight or less based on the calcium phosphate compound. If used in a larger amount, foaming becomes severe, and workability is reduced.

When the above-mentioned method of the present invention, that is, the method of impregnating or coating a nonwoven fabric with a dispersion of functional particles, is carried out, the concentration of the functional particles in the dispersion is adjusted to the nonwoven fabric. Although it can be appropriately selected according to the desired amount of support, it is usually 1 to 50% by weight, preferably 5 to 40% by weight in consideration of dispersibility and workability. Impregnation and coating may be performed once or twice or more to obtain a desired calcium phosphate loading.

When the above-mentioned method of the present invention, that is, the method of adding functional particles when producing a nonwoven fabric by a wet method, is carried out, the concentration of the functional particles in the aqueous dispersion is determined by using the raw material fiber. Can be appropriately selected depending on the compounding ratio of the raw material fiber, the desired amount supported on the nonwoven fabric, and the like.
% By weight.

After producing the nonwoven fabric carrying the functional particles by any of the above methods, the nonwoven fabric is heated to a temperature higher than the softening point of the used thermoplastic polymer fiber. This process softens and adheres the functional particles to the sticky fibers,
Particles are prevented from falling off.

[0020]

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Average particle size 3.5 μm, specific surface area 64 m ² / g, Ca / P ratio
1.67% porous hydroxyapatite granules 10% by weight
And an aqueous dispersion containing 0.05% by weight of sodium dodecyl sulfate. This dispersion liquid was impregnated with a nonwoven fabric (weight: 21 g / m ² ) having a thickness of 0.2 mm and made of 50% by weight of polyethylene and 50% by weight of polyester, and dried with hot air at 130 ° C. The hydroxyapatite loading ratio of the obtained nonwoven fabric was 22% by weight, and almost uniform loading was observed.

Example 2 Average particle size 0.55 μm, specific surface area 55 m ² / g, Ca / P
An aqueous dispersion containing 10% by weight of porous hydroxyapatite granules having a ratio of 1.67 and 0.05% by weight of sodium dodecyl sulfate was prepared. The dispersion was impregnated with a non-woven fabric (weight: 27 g / m ² ) of 100% by weight of polyethylene having a thickness of 0.4 mm and dried with hot air at 130 ° C. The hydroxyapatite loading rate of the obtained nonwoven fabric was 20% by weight, and almost uniform loading was observed.

Example 3 Average particle size 4.0 μm, specific surface area 64 m ² / g, Ca / P ratio
After preparing an aqueous dispersion containing 15% by weight of porous tetracalcium phosphate granules of 2.0 and 40% by weight of polypropylene raw fiber, a non-woven fabric was produced by a papermaking apparatus, and 170
It dried with the hot air of ° C. The loading ratio of tetracalcium phosphate in the obtained nonwoven fabric was 13% by weight, and almost uniform loading was observed.

Example 4 An aqueous dispersion containing 7% by weight of titanium dioxide granules having an average particle size of 20 μm was prepared. This dispersion is a nonwoven fabric of 100% by weight of polyethylene having a thickness of 0.2 mm (weight: 25 g / m ² )
And then dried with 130 ° C. hot air. The titanium dioxide loading of the obtained nonwoven fabric was 12% by weight, and almost uniform loading was recognized.

Example 5 A water-soluble dispersion containing 40% by weight of porous activated carbon granules having an average particle size of 150 μm and a specific surface area of 2500 m ² / g was prepared. After impregnating a non-woven fabric (weight: 30 g / m ² ) of 100% by weight of polyethylene having a thickness of 0.4 mm with this dispersion,
It was dried with hot air at 0 ° C. The activated carbon loading rate of the obtained nonwoven fabric was 25% by weight, and almost uniform loading was confirmed.

Example 6 An aqueous dispersion containing 20% by weight of zeolite granules having an average particle size of 10 μm was prepared. This dispersion is a non-woven fabric of 100% by weight of polyethylene having a thickness of 0.1 mm (weight: 15 g / m ² )
And then dried with 130 ° C. hot air. The zeolite loading of the obtained nonwoven fabric was 32% by weight, and almost uniform loading was observed.

Example 7 10% by weight of granules having an average particle diameter of 2 μm and a specific surface area of 3 m ² / g (trade name: manufactured by Sangi Co., Ltd.), 25% by weight of polyethylene raw fiber, and 15% of polyester raw fiber
After preparing a water-soluble dispersion containing a weight percent, a nonwoven fabric was manufactured using a papermaking apparatus and dried with hot air at 130 ° C.
The obtained nonwoven fabric had an aperider loading ratio of 15% by weight, and substantially uniform loading was observed.

Example 8 An aqueous dispersion containing 20% by weight of Kayamax (trade name, manufactured by Nippon Kayaku Co., Ltd.) granules having an average particle size of 75 μm was prepared. With this dispersion, a nonwoven fabric (weight 21%) consisting of 50% by weight of polyethylene and 50% by weight of polyester having a thickness of 0.2 mm is used.
g / m ² ) and dried with hot air at 130 ° C. The Kayamax carrying rate of the obtained nonwoven fabric is 19% by weight.
And almost uniform loading was observed.

Example 9 An aqueous dispersion containing 20% by weight of a dime shoe (trade name: manufactured by Dainichi Seika Kogyo Co., Ltd.) having an average particle diameter of 100 μm was prepared. 0.2mm thick polypropylene 1 with this dispersion
After impregnated with 00% by weight of a non-woven fabric (weight 24 g / m ² ), it was dried with hot air at 170 ° C. The dime shoe carrying rate of the obtained nonwoven fabric was 16% by weight, and almost uniform carrying was observed.

Comparative Example Average particle size 3.5 μm, specific surface area 64 m ² / g, Ca / P ratio
1.67% porous hydroxyapatite granules 10% by weight
And an aqueous dispersion containing 0.05% by weight of sodium dodecyl sulfate. The dispersion was impregnated with a non-woven fabric (weight: 21 g / m ² ) having a thickness of 0.2 mm and comprising 50% by weight of polyethylene and 50% by weight of polyester, and dried with hot air at 50 ° C. The hydroxyapatite carrying rate of the obtained nonwoven fabric was 3% by weight. There was uneven loading, and the hydroxyapatite fell off during vibration and handling, and the loading ratio became 1% by weight or less.

Virus Adsorption Experiment Influenza virus type B was buffered with 10 mM Tris-hydrochloric acid isotonic buffer (pH 7.2) containing 0.15 M sodium chloride (hereinafter referred to as "buffer").
The following experiment was performed using the liquid suspended in Tris isotonic solution). Tris isotonicity was used for all dilutions and suspensions in this experiment.

When the influenza virus attaches to red blood cells, the red blood cells cause an agglutination reaction. Utilizing this reaction, the virus suspension is doubled, 4x, 8x, 16x
The original virus suspension (the solution before dilution) is determined by mixing the two-fold serially diluted solution with the same amount of a 0.4% chicken erythrocyte suspension and causing agglutination up to the number of dilutions. The titer was evaluated. Furthermore, 125 cm ² of each of the nonwoven fabrics obtained in Example 1, Example 2, and Comparative Example was taken, and 6 ml of the virus suspension was brought into contact with each of them, and the titer was evaluated. Table 1 shows the results.

[0033]

[Table 1]

[0034]

As described above, the functional nonwoven fabric according to the present invention has the desired functional particles firmly fixed thereto, so that the loading ratio of the particles is remarkably improved, and the particles hardly fall off even after washing. In addition, since the surface of the functional particles is not covered with the binder, the performance is sufficiently exhibited, and as a result, the same effect can be achieved using a smaller amount of the functional particles than before, and the cost can be reduced. Can be reduced, and the weight can be reduced. The functional nonwoven fabric obtained by the present invention is excellent in air permeability, flexibility and tear strength since the nonwoven fabric is used as a base material. Further, the functional nonwoven fabric according to the present invention can support various functional particles and can be used for various applications.For example, when calcium phosphate compound particles are used as the functional particles, Since the calcium phosphate compound has an adsorbing action and a deodorizing action on various substances, the obtained functional nonwoven fabric is suitable for floor rubbing prevention sheets, deodorizing sheets, virus / bactericidal filters, opegans, and other healthcare-related products. .

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Koji Futaki, Inventor Asahi Kogaku Kogyo Co., Ltd. 2-36-9 Maeno-cho, Itabashi-ku, Tokyo (56) Reference JP-A-63-85177 (JP, A) JP-A-4-136273 (JP, A) JP-A-62-299582 (JP, A) JP-A-60-52661 (JP, A) JP-A-56-58051 (JP, A)

Claims (10)

(57) [Claims] 1. A nonwoven fabric in which at least a part of raw material fibers is made of a thermoplastic polymer fiber is impregnated or coated with an aqueous dispersion containing functional particles, and heat-treated at a temperature not lower than the softening point of the thermoplastic polymer fiber. A method for producing a functional nonwoven fabric, characterized in that functional particles are fixed at a contact portion with a thermoplastic polymer fiber which has become tacky and the surface of the remaining particles is exposed. 2. The functional particles having a Ca / P molar ratio of 1.
0 to 2.0 calcium phosphate compound, titanium dioxide, activated carbon, zeolite, molecular sieve, inorganic deodorant, inorganic antibacterial agent or a mixture thereof, powder, granule or porous having a particle size of 0.01 to 200 μm The method for producing a functional nonwoven fabric according to claim 1, which is a porous granule. 3. The method for producing a functional nonwoven fabric according to claim 1, wherein the aqueous dispersion contains 1 to 50% by weight of functional particles. 4. The method for producing a functional nonwoven fabric according to claim 1, wherein the aqueous dispersion further contains a surfactant in an amount of 15% by weight or less based on the functional particles. 5. The nonwoven fabric comprises a thermoplastic polymer fiber of 10-1.
2. The method for producing a functional nonwoven fabric according to claim 1, wherein the content is 00% by weight. 6. A non-woven fabric is produced by a papermaking technique using a raw material fiber comprising at least a portion of a thermoplastic polymer fiber and an aqueous dispersion containing functional particles having a particle size of 0.01 to 200 μm. A functional non-woven fabric characterized in that the functional particles are fixed at the contact portions by thermoplastic polymer fibers which have been heat-treated at a temperature higher than the softening point of the fibers and have become sticky, and the surface of the remaining particles is exposed. Manufacturing method. 7. The functional particles having a Ca / P molar ratio of 1.
0 to 2.0 calcium phosphate compound, titanium dioxide, activated carbon, zeolite, molecular sieve, inorganic deodorant, inorganic antibacterial agent or a mixture thereof, powder, granule or porous having a particle size of 0.01 to 200 μm The method for producing a functional nonwoven fabric according to claim 6, which is a porous granule. 8. The method for producing a functional nonwoven fabric according to claim 6, wherein the aqueous dispersion contains the functional particles in an amount of 1 to 200% by weight based on the weight of the raw material fibers. 9. The method for producing a functional nonwoven fabric according to claim 6, wherein the aqueous dispersion further contains a surfactant in an amount of 15% by weight or less based on the functional particles. 10. The nonwoven fabric comprises a thermoplastic polymer fiber of 10 to 10.
The method for producing a functional nonwoven fabric according to claim 6, which contains 100% by weight.