JPS6142314A - Fabric for separating colloidal fine particles - Google Patents

Abstract

PURPOSE:To separate a large number of colloid solutions each comprising a small amount in an extremely easy manner, by applying water guiding processing to a fabric comprising fibers each having recessed parts formed to the surface thereof in the axial direction. CONSTITUTION:A polyester or polyamide synthetic fiber multifilament is constituted of monofilaments each having at least one of a continuous groove shaped recessed part provided to the surface thereof in the fiber axis direction. The fineness of the monofilament is 1-5d, the total fineness of the multifilament is 50-100d and twisting is applied so as to adjust the number of twists to 100- 2,000 times/m. This multifilament is used to obtain a fabric wherein the sum of warp yarn density and weft yarn density is 210 piece/inch or more. Water guiding processing is preliminarily applied to this fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a fabric for separating colloidal fine particles used when separating fine particles and a dispersion medium from a colloidal solution.

(Example) Conventional technology Ultrafiltration membranes have been well known as a separation material for separating fine particles and a dispersion medium from a colloidal solution of fine particles with a particle size of about 0.5 to 20 Iin+. . for example,
Cellulose acetate membrane, collodion membrane, gelatin membrane,
Examples include cellophane membranes and sulfonated styrene membranes. These ultrafiltration membranes have countless pores of 0.5 μm or less, and by applying pressure, the dispersion medium, that is, water, can easily pass through the filtration membrane through the pores. Fine particles dispersed in water cannot easily pass through a filtration membrane, and this property can be used to separate the two.

Another well-known method is to use a centrifugal separator and utilize the difference in specific gravity between colloidal particles and a dispersion medium to separate them. Although these methods are extremely effective when separating relatively large amounts, they are not suitable when testing a large number of small quantities of samples in a short period of time, such as when inspecting fine particles in colloidal solutions or dispersion media. This is a great method. For example, when investigating the contents of water after colloidal particles have been removed from wastewater, a small amount of sample may be sufficient depending on the nature of the investigation. This method is inconvenient as it requires complicated operations and time.

(c) Problems to be Solved by the Invention The present invention requires complicated operations similar to conventional ultrafiltration or centrifugation methods to separate fine particles from a dispersion medium in a small amount of a large number of colloidal solutions. The object of the present invention is to provide a fabric for separating colloidal particles that can be carried out extremely easily.

(d) Means and action for solving the problems The present invention includes:
Single filament fineness 1~5d, total fineness 50~100d
, made of synthetic fiber multifilament yarn with 100 to 2000 twists per rice, the sum of warp density and weft density is 210
A woven fabric having a diameter of 1/2 or more, in which at least half of all single filaments in the woven fabric have at least one continuous recess in the fiber axis direction on the fiber surface, and the woven fabric is further subjected to a water-conducting treatment. This is a fabric for separating colloidal particles, which is characterized by the following.

That is, the first feature of the colloidal fine particle separation fabric of the present invention (hereinafter referred to as separation fabric) is:
The yarn constituting the fabric has a single filament fineness of 1 to 5 d,
Synthetic fiber multifilament yarn with a total fineness of 50 to 100 d and an IM number of 100 to 2,000 times/US, and at least half of all single filaments in the woven fabric have at least one continuous concavity formed on the surface in the fiber axis direction. The second point is that the woven fabric has a weaving density of 210 threads/inch or more as the sum of the warp density and the weft density, and the third point is that the woven fabric has a water conductive treatment. This means that

Due to the feature of the structure-1x described above, the separation fabric of the present invention allows the capillary phenomenon in the fiber gaps to effectively act to disperse the colloidal solution supplied to one side without requiring energy such as pressurization. Only the medium is allowed to pass through and transferred to the other side, allowing it to be separated from the fine particles.

The material fibers of the separating fabric of the present invention are synthetic fiber multifilament yarns such as polyester synthetic fibers and polyamide synthetic fibers. Synthetic fibers are hydrophobic, have low water absorption, have good dimensional stability against water, and have extremely good shape retention in fiber gaps.In particular, polyester synthetic fibers have other characteristics of the separation fabric of the present invention. One of the most preferable methods is that it can be easily carried out by etching with an aqueous solution of caustic soda. In addition to polyethylene terephthalate fibers, polyester synthetic fibers include polyethylene terephthalate as a main component, isophthalic acid,
Copolymerized polyester fibers copolymerized with a small amount of a third component such as roseoxybenzoic acid can also be used. Examples of polyamide synthetic fibers include fibers such as nylon 6 and nylon 66. Other polyolefin fibers such as polypropylene fibers and polyethylene fibers can also be used. Also, these fibers may be used in combination.

The synthetic fiber multifilament yarn constituting the separation fabric of the present invention has a single filament fineness of 1 to 5 d, a total fineness of 50 to 100 d, is heated to a twist number of 100 to 2000 twists per square inch, and is further twisted in the woven fabric. More than half of all single filaments have a small number of continuous groove-like recesses in the fiber axis direction on the surface, that is, the cross-sectional shape of the fiber is U-shaped or Y-shaped.

It is composed of single filaments with irregular cross-sections such as cross-shaped, plum-shaped, human-shaped, or modified shapes (hereinafter referred to as irregular cross-section single filaments). As mentioned above, it is necessary that more than half of all the single filaments in the fabric are single filaments of irregular cross section.For example, i) multifilament yarns consisting entirely of single filaments of irregular cross section are used in the warp and weft. ii) When using a multifilament yarn consisting of a single filament with an irregular cross section and a multifilament yarn consisting of a single filament with an irregular cross section and a single filament with a regular circular cross section, When one or several multifilament yarns consisting of circular cross-section single filament yarns are used alternately.

Furthermore, iii) A single multifilament yarn of irregular cross-section and a regular circular cross-section single filament is mixed so that the former accounts for more than half of the fibers, and the yarn is used alone, or it is made entirely of irregular cross-section single filaments. When mixed with multifilament yarn, iv) above i)
, ii), 1ii), etc., but it is desirable to select an embodiment in which the single filaments with irregular cross sections are distributed as uniformly throughout the fabric as possible. In addition, the proportion of irregular cross-section single filaments in all the single filaments in the fabric is as described above.
It may be determined in the range of half or more depending on the purpose of use and in relation to conditions such as yarn and weave density 1. As mentioned above, at least half of all the single filaments in the fabric are single filaments with irregular cross sections of 1 to 5 d having continuous groove-like recesses in the fiber axis direction on the surface, and each multifilament yarn is / By having the rice twist, the groove-like recesses on the surface of the irregular cross-section single filament and the gaps between the single filaments are finely adjusted by the twisting, and together with the water-conducting effect, fine particles do not pass through and the dispersion medium Fine, continuous voids are formed that can effectively exhibit the so-called capillary phenomenon, which allows the passage of only microorganisms. Therefore, the number of twists of the multifilament yarn is extremely important; if it is less than 100 twists per square meter, the capillary phenomenon cannot be sufficiently expressed, and if it exceeds 2000 twists per square meter, the voids will decrease, and
This is inappropriate as it may cause natural disasters. The total fineness of the multifilament yarn is related to the single filament fineness, the number of single filaments, the density of the fabric, the thickness, etc., but as mentioned above, <50 to 10
0d is appropriate.

Next, the purpose of the separating fabric of the present invention is to separate fine particles of a colloidal solution and a dispersion medium by the capillary effect of the voids in multifilament yarns forming the warp and weft, particularly multifilament yarns made of single filaments with irregular cross sections. Therefore, it is desirable to make the weave structure as dense as possible during weaving, and the warp density and weft density are in good harmony.
The sum of these must be 210 yarns/inch or more, and if it is less than 210 yarns/inch, even if the multifilament yarns serving as the warp and weft satisfy the above conditions, the texture of the fabric is This creates a large gap, making it difficult to obtain the desired separation property.

Furthermore, the separation fabric of the present invention is subjected to a water-conducting treatment. The synthetic fibers that are the material fibers of the separation fabric of the present invention are:
As mentioned above, although it is hydrophobic and has excellent dimensional stability against water, on the other hand, the water on the surface of the fiber
Less likely to cause wetting.

Therefore, even if the yarns and weaving density that make up the fabric have a physical structure that can effectively express the capillary phenomenon as described above, this alone cannot cause the "
Due to the lack of "wetness", it is not possible to sufficiently develop the capillary phenomenon.In contrast, the separation fabric of the present invention has been subjected to a water-conducting treatment, so that the separation fabric formed by the threads and texture of the fabric cannot be fully expressed. The surface of the microscopic voids is made hydrophilic, and "wetting" by water is large, and the capillary phenomenon is sufficiently developed, allowing only water, which is the dispersion medium of the colloidal solution, to pass through efficiently and exhibiting the desired separation properties. I can do it.

In the case of polyester-based synthetic fibers, suitable water conduction treatments include alkaline etching treatment of the fiber surface with aqueous caustic soda solution, or low-temperature plasma treatment with oxygen-containing gas; if more advanced performance is required, the former is recommended. After performing the alkaline etching treatment, the latter low-temperature plasma treatment using a gas containing oxygen may be performed. The former alkali etching treatment may be carried out under substantially the same conditions as those for the conventional weight loss treatment of polyester fiber fabrics, and the weight loss rate may be appropriately selected within the range of 5 to 20%. The latter low-temperature plasma treatment using a gas containing oxygen involves adding oxygen or oxygen and nitrogen, argon, or
This can be carried out by filling a mixed gas such as carbon dioxide gas or air, reducing the pressure with a vacuum pump, adjusting the pressure to 0.1 to 20 Torr, and then applying electrical energy to generate glow discharge. In this case, a high frequency (IKHz to 30 MHz) is preferable as the electrical energy source, but 13.56 MHz is usually used from the viewpoint of stability and uniformity of plasma generation, radio law regulations, etc. Direct wave output is 0.1 to 1
．． OW/cut.

The desired performance can be obtained with a processing time of 10 to 120 seconds.

Also, in the case of polyamide-based synthetic fibers and polyolefin-based synthetic fibers, water conductive processing can be effectively performed by the low-temperature plasma treatment using the oxygen-containing gas.

The separation fabric of the present invention has the above-described structure, and is extremely effective when used to separate a small number of colloidal solution samples into fine particles and a dispersion medium. It is also used when analyzing the components contained in water after it has been separated and removed. Particularly when performing a colorimetric test for dissolved components in wastewater, when the presence of dispersed fine particles poses an obstacle to the test, a sample liquid is dropped onto one side of the separation fabric of the present invention to separate the dispersion medium from the fine particles. This exudate can be allowed to ooze out to the other side, and necessary tests can be performed on this exudate. In addition, similar techniques can be used to separate the blood cell component and the blood cell component and perform necessary tests on each component.

(e) Example Polyethylene terephthalate multifilament yarns (75d/48f) with circular and irregular cross sections were used for the warp and weft, and the yarns were woven in a plain weave structure using a shuttle loom with varying twist numbers and weaving densities. The cross-sectional shape, number of twists, and weaving density of the single filament are as shown in Table 1. After each fabric was desized and refined in the usual way, it was divided into three equal parts, one part was subjected to alkaline etching treatment using caustic soda water/8 liquid, and the other part was subjected to low temperature plasma treatment, and each part was subjected to water conductive treatment. provided.

Each processing condition is as follows.

i) Alkaline etching treatment Treatment bath: NaOH40g/7! , bath ratio: 50 times.

Temperature: 98°C 5 hours = 60 minutes, then washed with water and dried.

ii) Low-temperature plasma treatment Gas used: 100% oxygen, pressure l Torr high frequency frequency: 13.56 MHz, output crab 0.4 W/
c+d.

Time = 1 minute The separation performance of each of the obtained treated fabrics and scoured fabrics was evaluated by the following method. The results are shown in Table 1.

Carbon with a particle size of 1 to 15 μm dispersed in water at a concentration of 0
．． 5g/1 of colloid solution at 20°C was applied to the surface of the separation fabric sample for 20μp, ? The passage of water and carbon to the back side of the separation fabric 1 minute after the Fa was removed was determined based on the degree of "wetness" on the back side and the state of coloration due to carbon (see Table 1 (2) bottom margin).

(Judgment criteria) ■... Extremely high water permeability, no coloring due to carbon.

0: High water permeability, no coloring due to carbon.

△...Low water permeability, no coloring due to carbon.

×: Water permeability is low, and there is some coloring due to carbon.

XX...Water permeability is high, and there is coloring due to carbon.

×××...Water permeability is extremely high and coloring due to carbon is strong.

As shown in Table 1, when the cross-sectional shape of a single filament is circular, the fabric with a low number of twists and low weave density (Sample No. 1) has a small water permeability after scouring, but some carbon particles can pass through it. However, if the water conductive treatment is applied, the coloring due to carbon becomes significant, and the fabric (sample No. 2) whose number of twists and weave density meet the conditions of the present invention has low water permeability even if the water conduction treatment is applied. . Furthermore, even if the cross-sectional shape of the single filament is U-shaped and the fiber surface has a groove-like concave portion continuous in the fiber axis direction, if the number of twists is small (
Sample No. 3> and when the weave density is low (sample No. 4)
After scouring, water permeability is low, and when water is treated, carbon particles pass through, making adjustment difficult. Sample N
The alkali-etched and low-temperature plasma-treated fabrics of 5.6.7.8 are examples of the present invention, and have high water permeability, and carbon particles do not penetrate at all. As a separation fabric, it was extremely loose.

(F) Effects of the Invention As mentioned above, the separation fabric of the present invention can suppress the capillary phenomenon in the fiber gaps by simply supplying a colloidal solution to one side of the fabric without using any energy such as pressurization. It is possible to effectively develop the dispersion medium to permeate and transfer to the other side of the fabric, and to separate the fine particles and the dispersion medium. Therefore, it is possible to easily and quickly separate a small amount and a large number of particles of a colloidal solution from a dispersion medium, which is extremely useful when inspecting particles and/or a dispersion medium.

Claims (1)

[Claims] (1) Single filament fineness 1-5d, total fineness 50-1
00d, a woven fabric consisting of synthetic fiber multifilament yarn with a twist count of 100 to 2000 twists per inch, with a sum of warp and weft densities of 210 threads/inch or more, in which at least half of all single filaments in the fabric are fibers. A woven fabric for separating colloidal particles, the woven fabric having at least one continuous recess in the fiber axis direction on its surface, and further having a water-conducting finish applied to the woven fabric.