JPH041650B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Industrial Application Field 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. (b) Prior Art Conventionally, ultrafiltration membranes are well known as a separation material for separating fine particles and a dispersion medium from a colloidal solution of fine particles having a particle size of about 0.5 to 20 μm. Examples include cellulose acetate membranes, collodion membranes, gelatin membranes, cellophane membranes, and sulfonated styrene membranes. These ultrafiltration membranes are
It has 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, while the fine particles dispersed in the 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. These methods are
Although this method is extremely effective when separating a relatively large amount, it is inappropriate when testing a large number of small quantities of samples in a short period of time, such as when inspecting fine particles in a colloidal solution or a dispersion medium. For example, when investigating the contents of water after removing colloidal particles from wastewater, depending on the content of the investigation,
There are cases where a small amount of sample is sufficient, and in such cases, the above separation 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 is a synthetic fiber multifilament yarn with a single filament fineness of 1 to 5 d, a total fineness of 50 to 100 d, and a twist count of 100 to 2000 twists per rice. and a woven fabric having a sum of weft yarn density of 210 filaments/inch or more, at least half of all the 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 further includes: This is a fabric for separating colloidal particles, which is characterized by being subjected to a water-conducting process. That is, the first feature of the colloidal particle separation fabric of the present invention (hereinafter referred to as separation fabric) is that the yarns constituting the fabric have a single filament fineness of 1 to 5 d and a total fineness of 50 to 100 d. , number of twists 100~
2000 times/US synthetic fiber multifilament yarn, and at least half of all the single filaments in the fabric have at least one continuous recess formed in the fiber axis direction on the surface, and the second The point is that the fabric is the sum of warp density and weft density.
It has a weaving density of 210 strands/inch or more,
The third point is that the fabric is treated to conduct water. Due to the above-mentioned structural features, the separating fabric of the present invention allows the capillary phenomenon of the fiber gaps to effectively act, and the dispersion medium of the colloidal solution supplied to one side of the fabric can be used without requiring energy such as pressurization. Only the particles can pass through and migrate to the other side, and can 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. As polyester synthetic fibers, in addition to polyethylene terephthalate fibers, copolymerized polyester fibers in which polyethylene terephthalate is the main component and a small amount of a third component such as isophthalic acid or paraoxybenzoic acid are copolymerized 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 separating fiber of the present invention has a single filament fineness of 1 to 5 d, a total fineness of 50 to 100 d, is twisted 100 to 2,000 times per twist, and is further twisted in the fabric. More than half of all single filaments in the single filament have at least one continuous groove-like recess on the surface in the direction of the fiber axis, that is, the cross-sectional shape of the fiber is U-shaped, Y-shaped, cross-shaped, plum-shaped, or human-shaped. Alternatively, it is composed of a single filament with a modified cross section (hereinafter referred to as a single filament with a modified cross section). 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, (2) multifilament yarns consisting of single filaments of irregular cross section should be used in the warp and weft. (2) 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 with the other being used for either the warp or the weft, When using a multi-filament yarn consisting of a single filament with a circular cross section and one or several filaments alternately, (2) a single filament with an irregular cross section and a single filament with a normal circular cross section are mixed so that the former accounts for more than half; When using a real multifilament yarn either alone or in combination with a multifilament yarn consisting entirely of single filaments of irregular cross section, any of the above (), (), combinations of (), etc. may be used. It is desirable to select an embodiment in which the irregular cross-section single filaments are distributed as uniformly throughout the fabric as possible. Furthermore, the proportion of the irregular cross-section single filaments in all the single filaments in the woven fabric may be determined within the range of half or more depending on the purpose of use and in relation to the conditions such as the yarn, weaving density, etc., as described above. As described 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 groove-like recesses continuous in the fiber axis direction on the surface,
In addition, since each multifilament yarn has twists of 100 to 2000 times per square inch, 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 twisting, which improves the water-conducting effect and the interaction. As a result, fine continuous voids are formed that can effectively exhibit the so-called capillary phenomenon, which allows only the dispersion medium to pass through and not the fine particles. Therefore, the number of twists of multifilament yarn is extremely important.
If it is less than 100 times per square meter, the capillary phenomenon cannot be sufficiently expressed, and if it exceeds 2000 times per square meter, the voids will decrease and double twisting will occur, which is unsuitable. The total fineness of the multifilament yarn is related to the fineness and number of single filaments, fabric density, thickness, etc., but as mentioned above, 50 to 100 d is appropriate. Next, the dispersion fabric of the present invention separates the fine particles of the colloidal solution and the dispersion medium by the capillary effect of the voids in the multifilament yarns forming the warp and weft, especially the multifilament yarns made of single filaments with irregular cross sections. For this purpose, it is desirable to make the weave structure as dense as possible during weaving, and it is necessary that the warp density and weft density are in good harmony, and that the sum is 210 threads/inch or more. If it is less than 1/2 inch, even if the multifilament yarns serving as the warp and weft satisfy the above conditions, large gaps will occur in the fabric structure, making it difficult to obtain the desired separation performance. It is. Furthermore, the separation fabric of the present invention is subjected to a water-conducting treatment. As mentioned above, the synthetic fiber that is the material fiber of the separation fabric of the present invention is hydrophobic, and
Although it has excellent dimensional stability against water, on the other hand, it is difficult for the fiber surface to "wet" with water. 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 will not "wet" the surfaces of those minute voids. Therefore, the capillary phenomenon cannot be sufficiently expressed. On the other hand, the separation fabric of the present invention has been subjected to a water-conducting process, so that the surface of the fine voids formed by the threads and texture of the fabric becomes hydrophilic, making it "wettable" by water. ” is large, sufficient capillary reduction occurs, and only water, which is the dispersion medium of the colloidal solution, is efficiently passed through, allowing the desired separation performance to be achieved. 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 of a gas containing oxygen involves filling a container containing the sample fabric with oxygen or a mixed gas of oxygen and nitrogen, argon, carbon dioxide, etc., or reducing the pressure with a vacuum pump.
This can be done by adjusting the temperature to 0.1 to 20 Torr and then applying electrical energy to generate a glow discharge. In this case, a high frequency (1KHz to 30MHz) is good as an electrical energy source, but it is usually
Uses 13.56MHz. High frequency output is 0.1~1.0W/
cm ² and a processing time of 10 to 120 seconds to achieve the desired performance. 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 blood cell components and plasma components 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 number of twists and weaving density were varied, and the yarns were woven in a plain weave structure using a shuttle loom. The cross-sectional shape, number of twists, and weaving density of the single filament are as shown in Table 1. Each fabric was desized and refined in a conventional manner, and then divided into three equal parts.One part was subjected to an alkaline etching treatment using a caustic soda aqueous solution, and one part was subjected to a low-temperature plasma treatment to perform a water conductive treatment.
The processing conditions are as follows. () Alkaline etching treatment Treatment bath: NaOH40g/, bath ratio: 50 times, temperature: 98℃, time: 60 minutes, then washing with water and drying. () Low temperature plasma treatment Gas used: 100% oxygen, Pressure: 1Torr High frequency: 13.56MHz, Output: 0.4W/
cm ² , 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. A 20 μm drop of a colloidal solution of carbon with a particle size of 1 to 15 μm dispersed in water at a concentration of 0.5 g/distance and a temperature of 20°C is applied to the surface of the separation fabric sample, and after 1 minute, the water is poured onto the back side of the separation fabric sample. The passage of carbon is measured by the degree of “wetness” on the back side and the state of coloration caused by carbon.

Judgment was made from [Table]. (Judgment criteria) ◎...Extremely high water permeability, no coloring due to carbon. ○…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. ××…Water permeability is high, and there is coloring due to carbon. ×××…Water permeability is extremely high and coloration due to carbon is strong. As shown in Table 1, when the cross-sectional shape of the single filament is circular, the fabric with a low number of twists and weaving density (Sample No. 1) has a low water permeability after scouring, but some carbon particles can pass through it. However, if the water conductive treatment is applied, the coloration due to carbon becomes significant, and the fabric (sample No. 2) whose twist number 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, the yarn has a small number of twists (Sample No. 3) and a low weaving density. Case (sample no.
Regarding 4), water permeability is low after scouring, and carbon particles permeate through the water-conducting process, making adjustment difficult. The fabrics of samples Nos. 5, 6, 7, and 8 that were subjected to alkali etching treatment and those that were subjected to low-temperature plasma treatment are examples of the present invention, and have high water permeability and no carbon particles permeate at all. It was an excellent separation fabric. (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~
100d, 100 to 2000 twists per US synthetic fiber multifilament yarn, with a sum of warp and weft density of 210 threads/inch or more, at least half of all single filaments in the textile 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.