KR102375856B1 - Nonwoven having adsorption of radioactivity and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing a radioactive adsorption functional nonwoven fabric, comprising: spinning a spinning composition containing polyester and zeolite having a melting point of 250° C. or higher through a spinneret having a discharge hole having a different cross-section to obtain a filament with a different cross-section; Laminating the web of the filaments with the heterogeneous cross-section; and entangling the web by needle punching. It provides a manufacturing method comprising a.
According to the present invention, the nonwoven fabric made of a polyester cross-sectional yarn containing zeolite has a wide surface area and, when used as a filter medium, highly absorbs radioactive contaminants dissolved in contaminated water or leachate with high efficiency, while maintaining excellent durability, The voids are increased in the nonwoven fabric due to the entanglement between the fibers of different cross-sections, making it possible to improve the permeability when used as a filter medium.

Description

Nonwoven having adsorption of radioactivity and manufacturing method thereof

The present invention relates to a functional nonwoven fabric having excellent durability while performing a radioactive adsorption function.

With the increase in the construction of nuclear power plants, there are growing concerns about the dangers of radioactive materials. Radioactive materials can be exposed in situations such as accidents at nuclear power plants, radioactive waste, or dismantling of old nuclear power plant facilities. Since it can cause serious damage to the human body and ecosystem, the development of stable treatment technology is required. In particular, cesium and heavy metals require an efficient removal method for reasons such as half-life and effects on the ecosystem and human body.

In the existing method, the method of applying to contaminated areas and soil using zeolite and Prussian blue powder, known as functional substances that adsorb cesium (Cs137), a radioactive pollutant, is not recoverable after application. It is difficult and difficult to apply to contaminated sedimented water (groundwater).

Therefore, the method of using sheet and fabric type products containing zeolite and Prussian blue is the most recently used. In the case of using the sheet and fabric form, collection is easy, and contaminants in the sedimentation water can be removed by filtering.

Functional material-containing sheets generally attach functional materials that absorb contaminants to the sheet surface through an adhesive or heating process. It may fall off the surface, and the removal efficiency may fall.

Because the sheet containing functional materials is used in various places such as buildings, soil, and sediment (groundwater), durability of the sheet in the external environment is important, and products of various thicknesses, densities, and shapes are required depending on the place of use.

Republic of Korea Patent Publication 2015-0145807 (Prussian blue-supported nanofiber composite for adsorption of radioactive cesium, filter media using the same, and method of decontamination of radioactive cesium)

An object of the present invention is to provide a functional nonwoven fabric with improved durability while improving adsorption performance of radioactive contaminants in response to the above problems and needs.

In order to solve the above problems, the present invention is made of a filament with a different cross-section including polyester and zeolite, and has a tensile strength (KS K 0743 method) of 1000 to 1300 N, and a breaking strength (KS K ISO 11058 method) of 2700 To provide a functional nonwoven fabric with radiation absorption of ~3300 KPa.
In addition, the present invention provides a method comprising: spinning a spinning composition containing polyester and zeolite having a melting point of 250° C. or higher through a spinneret having a discharge hole having a different cross-section to obtain a filament with a different cross-section; Laminating the web of the filaments with the heterogeneous cross-section; and needle-punching the web to entangle the web.

According to the present invention, when a nonwoven fabric made of a polyester cross-sectional yarn containing zeolite has a wider surface area and is used as a filter medium, it is possible to efficiently adsorb radioactive contaminants dissolved in contaminated water or leachate while maintaining excellent durability. Do.

In addition, voids are increased in the nonwoven fabric due to entanglement between the fibers of different cross-sections, making it possible to improve the permeability when used as a filter medium.

1 is a diagram schematically showing the shape of the deformed cross-section of the filament constituting the nonwoven fabric according to the present invention.

The present invention comprises a method of manufacturing a nonwoven fabric by spinning polyester containing zeolite as a functional material to produce a filament having a different cross-section, forming a web with the filament, and then entangling it by a needle punch method.

Polyester fiber nonwoven fabric has excellent durability, chemical resistance, and environmental resistance, and in particular, has superior radiation resistance than other fibers, so it is not easily decomposed by radiation. It can be used not only as a single body, but also as a filter material for other finished products such as filters. In the present invention, it is more preferable to use a polyester fiber nonwoven fabric using polyethylene terephthalate having a melting point of 250° C. or higher.

In the present invention, the polyester fiber is a polyester fiber including zeolite.

First, a spinning composition is prepared by mixing polyethylene terephthalate for fibers and zeolite, and in this case, the content of the zeolite in the composition is preferably 10 to 30% by weight.

Zeolite has a chemical composition of SiO ₂ ·Al ₂ O ₃ , and is a porous material with numerous micropores of a certain diameter. It has strong adsorption properties to adsorb and remove various harmful substances, as well as deodorizing action such as odor removal and removing bacteria. It has a purifying action.

Considering the maximization of the above actions and effects, the zeolite preferably has an average particle diameter of 3 to 10 μm.

If the content of the zeolite in the spinning composition of the present invention is less than 10% by weight, the removal performance of radioactive contaminants is reduced, and when it exceeds 30% by weight, the zeolite is an inorganic particle and is present in the form of particles without being melted at a high temperature. Since it becomes a foreign material, the flow of the melt may not be uniform in the process of extruding the molten polyester spinning composition during melt spinning, and the filament to be molded by stagnant in the extruder may not be uniform.

In the present invention, since fibers are manufactured by including zeolite in the spinning composition, fibers are manufactured in various shapes with zeolite included, so compared to the method of attaching zeolite after manufacturing fibers, productivity is improved and quality is uniform of fibers can be produced.

To explain this in more detail, in the method of attaching the zeolite to the fiber surface, uniform adhesion between the fiber and the zeolite is difficult, making it difficult to achieve uniform performance on the entire surface of the nonwoven fabric. Because polyester and zeolite are uniformly mixed, uniform performance can be expressed on the entire surface of the nonwoven fabric.

In addition, since the zeolite, which is a functional material, does not fall off, the radiation adsorption efficiency is improved, and the adsorption performance can be maintained for a long period of time.

The polyester fiber of the present invention supplies a spinning composition in which polyethylene terephthalate and zeolite having a melting point of 250° C. are mixed with an extruder, and through a spinneret having a discharge hole of a different cross-sectional shape (based on a vertical section of the spinning composition moving passage) It can be manufactured by stretching the spun filament sufficiently to a spinning speed of 4500-5000 m/min using a high-pressure air stretching device and molding it into a filament with a heterogeneous cross-section of 3 to 7 denier.

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등 중심선을 중심으로 방사 바깥방향으로 가지가 뻗어있는 형태를 가질 수 있다. As shown in FIG. 1, the cross-section of the filament of the heterogeneous cross-section is Y-shaped, cross (+)-shaped,

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It may have a shape in which branches extend radially outward from the center line of the back.

Because the filament has the above shape, when the number, density and needle stroke of the needles are reduced when manufacturing the nonwoven fabric by needle punching, the entanglement between fibers is improved and the damage to the filaments is minimized, so that the strength of the nonwoven fabric is expressed and high thickness Non-woven fabrics can be produced.

In addition, according to the above shape, compared to using a filament of the same thickness, the surface area of the filament according to the present invention becomes wider, so that when applied as a filter medium, the contact area increases, so the removal efficiency can be improved.

In addition, the voids due to entanglement between the filaments increase in the nonwoven fabric according to the above configuration, so that permeability can be improved when used as a filter medium.

At this time, when the filament with the irregular cross-section is less than 3 denier, the filament is thin and weak in strength, and the number of filaments per unit area increases. If the denier is exceeded, the strength is improved, but when applied as a filter medium, the water permeability and the removal efficiency of radioactive contaminants are lowered, so it is not desirable.

Thereafter, the filaments with a different cross-section are laminated on a conveyor in the form of a web, passed through a heated calender roll device to adjust the thickness, and then the filaments are entangled by needle punching to prepare a nonwoven fabric. At this time, the needle punching can be performed under the conditions of a needle density of 1 to 5 ea/cm2, and a needle punching range of 600 to 1,000 strokes.

In the present invention, by producing a nonwoven fabric by needle punching a web of filaments with a different cross-section, compared to other nonwoven manufacturing methods such as thermal bonding method by physical (roll) high pressure, and jet method accompanied by pressure by air or water, higher after As the thickness of the nonwoven fabric decreases in the filter media constituting the filter, the size and number of pores between the filaments decrease, thereby reducing the surface area and reducing the service life due to low permeability. .

In addition, since there is no adhesive (fusion) portion between the filaments of the nonwoven fabric, the surface area of the nonwoven fabric may be increased and the permeability may be improved.

Due to this, it can be used as a filter medium required in a filter for purification of soil and water pollution.

A functional filter can be manufactured by processing the nonwoven fabric of polyester fiber containing zeolite produced according to the present invention in the same structure as a general filter medium so that it can be applied to filters such as cartridge-type, bent-type, and flat-type filters.

The functional filter according to the present invention has a large surface area of the filaments of the nonwoven fabric constituting the filter medium and excellent entanglement, and uses the nonwoven fabric, which is easy to mold into products of various thicknesses, densities, and shapes, as a filter medium. While the removal efficiency is improved, the mechanical strength is excellent, and thus durability can be improved even in continuous filtering.

Hereinafter, the present invention will be described in more detail based on the following Examples, Comparative Examples and Test Examples.

However, the following examples are only for illustrating the present invention, and the present invention is not limited by the following examples, and can be substituted and changed to other equivalent examples without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in the art to which the present invention pertains.

<Examples 1-4> and <Comparative Examples 1-4>

Polyethylene terephthalate having a melting point of 255°C including zeolite powder was melted at 288°C using a continuous extruder, and then spun through a spinneret including a discharge hole.

At this time, the content of the zeolite and the shape of the discharge hole were as shown in Table 1 below.

Then, after the continuous filaments discharged from the spinneret were solidified with cooling air, they were sufficiently drawn using a high-pressure air drawing device to obtain a spinning speed of 5,000 m/min to prepare filament fibers.

In this case, the discharge amount and the number of pores of the spinneret were adjusted so that the fineness of the prepared filament was as shown in Table 1 below.

Next, the prepared filament fibers are laminated in the form of a web on a conveyor net by a conventional fiber opening method, and then strength is imparted by a needle punch method to prepare a nonwoven fabric having a weight per unit area of 400 gsm did

zeolite
content
(wt%) filament
cross-sectional shape
(Discharge hole shape) fineness
(De') Example 1 10 Y-shaped 4 Example 2 20 Y-shaped 4 Example 3 20 Y-shaped 6 Example 4 30 Y-shaped 4 Comparative Example 1 20 O-shaped (round) 4 Comparative Example 2 5 Y-shaped 4 Comparative Example 3 40 Y-shaped 4 Comparative Example 4 20 Y-shaped 10

<Test Example> Measurement of physical properties

The physical properties of the nonwoven fabric of Examples and Comparative Examples prepared above were measured and shown in Table 2 below.

Tensile strength is measured using the KS K 0743 method.

The permeability coefficient (unit: cm/sec) is measured using the KS K ISO 11058 method.

Bursting strength (unit: KPa) is measured using the KS K ISO 13938-1 method.

The cesium removal rate is measured by measuring the cesium content of the filtered cesium preparation water by passing 100 L of 1.98 ppm cesium preparation water through a filter cartridge made of a nonwoven fabric at a pressure of 3.0 kgf/cm 2 .

tensile strength
(N) pitcher coefficient
(cm/sec) burst strength
(KPa) Cesium Removal Rate
(%) Example 1 1090 2.8 × 10 ^-1 2780 92.77 Example 2 1240 3.0 × 10 ^-1 3120 93.73 Example 3 1320 4.0 × 10 ^-1 3250 92.71 Example 4 1130 2.9 × 10 ^-1 2960 94.31 Comparative Example 1 1210 3.4 × 10 ^-1 3160 72.38 Comparative Example 2 1050 3.1 × 10 ^-1 2870 76.23 Comparative Example 3 Unable to manufacture filament Comparative Example 4 1560 4.9 × 10 ^-1 3390 78.96

From Table 2, it was confirmed that, in particular, the nonwoven fabric according to Example 3 exhibited balanced characteristics with excellent cesium removal rate and excellent mechanical strength and filtering efficiency.

If the zeolite content is too high, inorganic particles act as impurities, making it difficult to manufacture fiber filaments (Comparative Example 3), and when the fiber filaments are circular rather than heterogeneous, the cesium removal rate is reduced (Comparative Example 1), and fineness is increased Even so, it was confirmed that the cesium removal rate was lowered (Comparative Example 4).

As described above, it can be confirmed that the nonwoven fabric of the present invention exhibits excellent and balanced properties in cesium removal rate, tensile strength, permeability coefficient, and burst strength compared to the comparative example.

Claims (5)

It consists of a filament with a different cross-section containing polyester and zeolite, and has a tensile strength (KS K 0743 method) of 1000 to 1300 N, and a breaking strength (KS K ISO 11058 method) of 2700 to 3300 KPa,
The irregular cross-section filament includes an interlaced yarn in which a web of irregular cross-section filaments spun from a melt spinning composition is needle-punched,
The fineness of the filament of the heterogeneous cross-section is 3 to 7 denier of radioactivity adsorption functional nonwoven fabric. The method of claim 1,
The radioactive adsorption functional nonwoven fabric, characterized in that the content of the zeolite in the heterogeneous cross-section filament is 10 to 30 wt%. The method of claim 1,
The irregular cross section has a Y-shape, a cross (+) shape,

and

Radioactive adsorption functional nonwoven fabric, characterized in that selected from. delete spinning a spinning composition including polyester and zeolite having a melting point of 250° C. or higher through a spinneret having a discharge hole having a different cross-section to obtain a filament with a different cross-section;
Laminating the web of the filaments with the heterogeneous cross-section; and
Including; entangling the web by needle punching;
The step of obtaining a filament with a different cross-section comprises the step of manufacturing a filament with a different cross-section having a fineness of 3 to 7 denier by stretching to a spinning speed of 4500 to 5000 m/min and manufacturing the filament of claim 1, manufacturing method.

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