JPH05295124A - Functional material and production thereof - Google Patents

Abstract

PURPOSE:To obtain a functional material having a large amt. of a functional powder fixed on a porous material with fibrillated polytetrafluoroethylene, by applying on the porous material a milled mixture of the functional powder and polytetrafluoroethylene with water, followed by drying. CONSTITUTION:A functional powder (e.g. activated carbon or zeolite) and polytetrafluoroethylene are mixed with water and milled together to fibrillate the polytetrafluoroethylene. The resulting mixture is applied on a porous material (e.g. a nonwoven fabric), and dried to obtain a functional material. According to the foregoing procedure, a large amt. of the functional powder is fixed on the porous material with a three-dimensional network of polytetrafluoroethylene made into a fine self-adhesive fibrous form through fibrillation thereof, with the result that the surface of the functional powder is not wholly covered with polytetrafluoroethylene without detriment to the function of the functional powder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a functional material containing a functional powder such as a deodorant and a catalyst, and a method for producing the functional material. More specifically, the present invention relates to a functional material in which a large amount of the functional powder is fixed without impairing the function of the functional powder, and the powder does not easily fall off, and a method for producing the functional material.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
There is known a functional material in which powder having a specific function such as a deodorizing function, an ozone decomposing function, a catalyst function, and a filtering function is fixed to a porous body such as a non-woven fabric, a cloth or a foam. By fixing the functional powder to a porous body having a large surface area, these functional materials can pass through the inside of the functional material,
For the substance that comes into contact with the functional material, the peculiar function of the functional powder has been sufficiently exerted. As such a functional material, for example, there is a deodorizing sheet in which a powder having a deodorizing function such as activated carbon is attached to the surface of constituent fibers such as a nonwoven fabric. There is also a freshness-keeping sheet in which sepiolite, zeolite or the like is attached to the surface of the constituent fibers of the non-woven fabric to remove ethylene gas generated from vegetables and the like to keep the freshness of vegetables for a long time.

In these functional materials, the functional powder is adhered to the porous body through a binder or an adhesive fiber. In the case of a functional material in which a functional powder is attached to a porous body using a binder, the surface of the powder is covered with the binder, so the substance or function that allows the functional powder to pass through the functional material. There is a problem that it is impossible to contact the substance that comes into contact with the conductive material, or only a part of the powder can come into contact with the substance, and the function of the powder cannot be sufficiently exerted for the substance. On the other hand, when the adhesive fiber is used, the porous body and the powder are only partially adhered to each other, and the powder easily comes off from the porous body during production or use of the functional material. There was a problem that it ended up. Further, in the functional material using the adhesive fiber, the porous body itself used is limited to the one which can use a large amount of fiber, and moreover, many powders cannot be fixed. Further, since the adhesive fiber is used, it cannot be used in a high temperature atmosphere.

The present invention has been made in view of the above problems, and a large amount of the functional powder is fixed, so that a large amount of the functional powder can be obtained without impairing the function of the functional powder. An object of the present invention is to provide a functional material which is fixed and whose powder does not easily fall off, and a manufacturing method thereof.

[0005]

In order to achieve the above-mentioned object, the invention according to claim 1 provides "a fibrillated polytetrafluoroethylene (hereinafter PTFE).
The functional material is characterized in that the functional powder is fixed to the porous body ".

According to the second aspect of the present invention, "PT is obtained by mixing functional powder, PTFE and water and kneading them.
The essence is "method for producing functional material characterized by fibrillizing FE, and then applying the kneaded product to a porous body and drying."

According to the invention of claim 3, "a method for producing a functional material, characterized in that the amount of water in the kneaded material is 2 to 20 times the amount of the functional powder" is summarized. And

The functional material of the present invention and the method for producing the same will be described below in detail. The functional material of the present invention is a porous material in which functional powder is fixed by PTFE. As functional powders, "manganese dioxide" used in ozone decomposition sheets, "activated carbon" used in deodorizing sheets for deodorizing ammonia odor, "zeolite", "ceragit", "sepiolite", tobacco odor, sulfur oxides , "Activated carbon" used for removal sheet to remove nitrogen oxide, "Zeolite" used for removal sheet to remove thiol and hydrogen sulfide, "Sepiolite" used for freshness retention sheet to remove ethylene gas generated from vegetables etc. , "Zeolite", "potassium titanate" used for a sake filtration sheet, "sepiolite" used for a liquid adsorption filtration sheet in soy sauce, and the like.

As the porous body, any of those conventionally known as porous materials can be used. The material, density, size, shape, number of pores, size of pores, etc. of the porous body are as follows. The functional material can be appropriately selected and used according to the application. For example, non-woven fabrics, woven fabrics, knitted fabrics, porous plastic films, and foams are generally known as porous materials. In addition, as a porous body manufactured for use in a special purpose, a particle shape-adjusted particle such as glass beads is point-bonded and molded into a predetermined shape, its carbide, or a plant or animal tissue is used as it is. However, there are also carbonized products. In particular, since the non-woven fabric has a large surface area and a low resistance when the liquid to be treated passes, it is possible to efficiently use the function of the functional material attached to the surface of the constituent fibers of the non-woven fabric.

It is known that PTFE is easily fibrillated by applying a shearing force to form a sticky fine fiber. In the functional material of the present invention, the functional powder is adhered and fixed to the porous body by this PTFE. Incidentally, when the density of the porous body is low,
The functional powder is fixed on the surface of the material that makes up the porous body, but when the density of the porous body is high, it is functional not only on the surface of the material that makes up the porous body, but also on the space between the materials. The powder is fixed.

As described above, in the functional material of the present invention, a large amount of the functional powder is fixed to the porous body by the PTFE which is made into a fine fibrous substance by fibrillation. Therefore, the whole surface of the functional powder is not covered with PTFE, the function of the functional powder is not impaired, and the substance that passes through the inside of the functional material or comes into contact with the functional material is , The function of the functional powder is fully exerted. Further, in this functional material, since the functional powder is fixed to the porous body by the PTFE which has been fibrillated into a fine fibrous form, the functional material functions at the time of production or use of the functional material. The powdery nature does not fall off easily.

Next, the method for producing the functional material of the present invention will be described. This method has a step of mixing and kneading the functional powder, PTFE and water, and a step of applying the kneaded material to a porous body and drying it. First, the type of the functional powder, the average particle size, etc. are selected according to the application of the functional material. The average particle size of the functional powder is not particularly limited, but if the average particle size is too large, the functional powder cannot be fixed in a uniformly dispersed state in the porous body, and the unit weight of the functional powder is not fixed. The contact area per hit becomes small, and the function of the functional powder cannot be sufficiently exerted on a substance that passes through the inside of the functional material or comes into contact with the functional material. Although PTFE may be mixed with the functional powder and water in the form of powder, it is desirable that PTFE is in the form of dispersion in order to facilitate uniform dispersion of the mixture. In this case, the functional powder may be added to the PTFE dispersion, and then a necessary amount of water may be added. The PTFE content in the mixture is appropriately determined according to the amount of functional powder, the type and size of the porous body.

The amount of water in the mixture is preferably 2 to 20 times the weight of the functional powder, though it depends on the type of the functional powder and the amount of PTFE.
If the amount of water is less than this, the viscosity of the obtained kneaded product becomes high, making it difficult to add it to the porous body, and if the amount of water is more than this, the functionality that practically adheres to the porous body The amount of powder becomes small and the desired effect cannot be obtained. When it is desired to adhere the functional powder only to the surface of the constituent material of the porous body, it is preferable that the kneaded material has high fluidity, so that the amount of water is 5 to 20 times, especially 7 to 15 times. If it is desired to retain the functional powder also in the voids between the constituent materials of the porous body, it is desirable that the fluidity of the kneaded product is relatively low.
It is good to be 5 times, especially 3 to 5 times. In addition, it is advisable to add methanol, ethanol, isopropyl alcohol, ethylene glycol, glycerin, ethyl cellosolve or the like, which promotes fibrillation of PTFE, to the mixture of PTFE, functional powder and water. In this case, mixing with water is recommended. As a solution, it may be mixed with PTFE or functional powder.

These functional powders, PTFE and water are mixed and kneaded. The kneading is carried out using a conventionally known mixing stirrer, kneader, ball mill, Banbury mixer, roll mixer, screw mixer and the like. It can be carried out. Through this mixing and kneading process, PTF
E becomes fibrillated. The fibrillated PTFE is entwined around the functional powder. It is desirable that the kneaded product is in a liquid state. In this case, PTFE is dispersed in the liquid in a state of being entangled with the periphery of the functional powder, and the PTFE and the functional powder are dispersed in the subsequent applying and drying steps. It becomes fixed in a dispersed state on the porous body.

Next, this kneaded material is applied to the porous body. As the applying means, methods such as impregnation, coating and spraying can be adopted. By these imparting means, the kneaded product is in a state of being uniformly dispersed throughout the porous body. After that, the functional powder and the PTFE dispersion in the kneaded product are made porous by the natural or forced drying. It is adhered and fixed to the surface and the surface of the material forming the porous body.

[0016]

【Example】

Example Functional powder: Lionite PF (granular deodorant consisting of silica and metal oxide, manufactured by Lion Corporation) 15% by weight
And PTFE dispersion: polyflon (dispersed about 60% of PTFE particles having an average particle size of 0.15 to 0.35 μm, manufactured by Daikin Industries, Ltd.) 6.25% by weight
33.75% by weight of isopropyl alcohol and 4 parts of water
Mix with 5% by weight of paste (water / Liolite PF
After creating ≈3, a non-woven fabric obtained by impregnating a vinyl chloride resin emulsion into a fibrous web composed of polyclar fiber and polyester fiber and coating the paste onto the non-woven fabric is dried at a temperature of 100 ° C. using a dryer to remove the deodorant sheet. Got The solid content ratio of the obtained sheet was 4: 1 of lionite PF: polyflon. An electron micrograph and a schematic view of the fiber structure of this deodorizing sheet (Fig. 1
~ 6). From the electron micrographs of FIGS. 1 to 6 and the schematic diagrams thereof, the deodorant 2 is the PTFE on the constituent fiber 1 of the non-woven fabric.
It is understood that the structure is fixed by No. 3, and the surface of the deodorant 2 itself is not covered, and the structure can sufficiently exhibit its function.

Comparative Example 1 Functional powder: Lionite PF (granular deodorant consisting of silica and metal oxide, manufactured by Lion Corporation) 15% by weight
And binder: Sumika Flex 850 (vinyl chloride resin emulsion, manufactured by Sumitomo Chemical Co., Ltd.) 3% by weight
(Amount of solid content) and water were mixed to form a paste, which was then impregnated into the same non-woven fabric as used in the examples, and this was dried at a temperature of 150 ° C. using a dryer to remove the deodorant sheet. Got The solid content ratio of the obtained sheet was 5: 1 for Lionite PF: Sumikaflex 850. The fiber structure of this deodorizing sheet is shown in an electron micrograph and its schematic diagrams (FIGS. 7 to 12). From the electron micrographs of FIGS. 7 to 12 and the schematic diagrams thereof, it is understood that the deodorant 2 is fixed on the constituent fibers 1 of the nonwoven fabric by the binder 4, and the surface of the deodorant 2 itself is covered with the binder 4.

Comparative Example 2 Functional powder: Lionite PF (granular deodorant consisting of silica and metal oxide, manufactured by Lion Corporation) was wrapped in a tissue.

The deodorizing sheets and deodorizing bags of the above Examples, Comparative Examples 1 and 2 were subjected to a deodorizing test for methyl mercaptan. For the deodorization test, the deodorization sheet 10 of the above Example, Comparative Example 1 and Comparative Example 2 was placed in a 5 liter conical flask.
cm × 10 cm (Lionite PF 0.6g attached), deodorant bag Lyonite PF 0.6g enclosed) is hung with a wire, and standard solution of methyl mercaptan (1μg / μl benzene) 4
Inject 00 μl using a microsyringe. After a predetermined time had elapsed, the residual concentration (C) of methyl mercaptan in the flask was measured using a Kitagawa gas detector. In addition, the concentration of methyl mercaptan was also measured for the sample containing no deodorant, and the blank concentration was defined as (C _O ), and the residual concentration (C) in each sample was evaluated by (C / C _O ). Residual rate of methyl mercaptan at each time (C
/ C _O ) is shown in FIG. As is clear from FIG. 13, the deodorizing sheets of the examples had the same high deodorizing effect as a bag in which the deodorant was simply wrapped with a tissue. It was also confirmed that the deodorizing sheet of the example had a much higher deodorizing effect than the deodorizing sheet of Comparative Example 1.

[0020]

According to the present invention, the above-mentioned structure is provided.
In the described functional material, a large amount of the functional powder is fixed to the porous body by the three-dimensional structure of PTFE, which is a fine fibrous sticky substance formed by fibrillation. , The entire surface of the functional powder is not covered with PTFE, the function of the functional powder is not impaired, and substances that pass through the inside of the functional material or come into contact with the functional material, The function of the functional powder is sufficiently exerted, and the functional powder does not easily fall off during production or use of the functional material.

In the method for producing a functional material according to claim 2, a large amount of the functional powder is fixed without impairing the function of the functional powder, and the powder is easily prepared. It is possible to obtain a functional material that does not fall off.

In the method for producing a functional material according to a third aspect, by using a kneaded material having high fluidity, the functional powder can be spread all over the surface of the constituent material of the porous body. PT for porous materials with a large surface area
The adhesion processing of the functional powder by FE can be enabled.

[Brief description of drawings]

FIG. 1 is an electron micrograph showing a fiber structure of a deodorizing sheet of an example.

FIG. 2 is a schematic view showing a fiber structure of the deodorizing sheet.

FIG. 3 is an electron micrograph showing the fiber structure of the deodorizing sheet of the example.

FIG. 4 is a schematic diagram showing a fiber structure of the deodorizing sheet.

FIG. 5 is an electron micrograph showing the fiber structure of the deodorizing sheet of the example.

FIG. 6 is a schematic diagram showing a fiber structure of the deodorizing sheet.

FIG. 7 is an electron micrograph showing the fiber structure of the deodorizing sheet of Comparative Example 1.

FIG. 8 is a schematic diagram showing the fiber structure of the deodorizing sheet.

FIG. 9 is an electron micrograph showing the fiber structure of the deodorizing sheet of Comparative Example 1.

FIG. 10 is a schematic view showing a fiber structure of the deodorizing sheet.

11 is an electron micrograph showing the fiber structure of the deodorizing sheet of Comparative Example 1. FIG.

FIG. 12 is a schematic diagram showing the fiber structure of the deodorizing sheet.

FIG. 13 is a graph showing the residual ratios of methyl mercaptans of Examples and Comparative Examples 1 and 2 at respective times.

[Explanation of symbols]

 1 Constituent fiber of non-woven fabric 2 Deodorant 3 PTFE 4 Binder

Claims (3)

[Claims] 1. A functional material characterized in that the functional powder is fixed to a porous body by fibrillated polytetrafluoroethylene. 2. A polytetrafluoroethylene is fibrillated by mixing and kneading the functional powder, polytetrafluoroethylene and water, and then the kneaded product is applied to a porous body and dried. Method for producing a functional material. 3. The method for producing a functional material according to claim 2, wherein the amount of water in the kneaded product is 2 to 20 times the amount of the functional powder.