JPH01282390A - Ultra-fine ion-exchange fiber and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject ion-exchange fiber having extremely high ion- exchange speed and exhibiting remarkable effect in the ion-exchange and adsorption separation in dilute state by graft-polymerizing ion-exchange group to ultrafine fibers. CONSTITUTION:An ultrafine fibrillated fibers having a fiber diameter of 0.00001-0.1mum are produced by spinning a multicore sea-island type composite fiber composed of polyester, polyamide, etc., drawing said composite fiber and removing the sea-component from the product. The fibrillated ultrafine fiber is immersed in an acidic vinyl monomer having carboxyl group, preferably a solution of a mixture of acrylic acid and methacrylic acid and the monomers are polymerized to obtain an ultrafine ion-exchange fiber containing cation- exchange group introduced into the fiber. Since the obtained fiber has large specific surface area and extremely high ion-exchange rate, it can be suitably applied in a wide application field such as the softening of water, desalination of sea water and removal of harmful metals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to ultrafine ion exchange fibers and a method for producing the same.

[Prior Art] Conventionally, ion exchange resins have been widely used in industrial fields requiring ion exchange and adsorption.

However, since the exchange groups of the ion exchange resin are much more present inside the network structure than on the surface of the resin particles, some problems remain in terms of reaction rate compared to the size of the total exchange capacity.

Furthermore, since the diffusion rate into the interior of the particles is very low, the exchange capacity over a given period of time is small.

If we try to compensate for these drawbacks with resin, we have no choice but to make the particle size as fine as possible to increase the specific surface area. Clogging and increased pressure loss occur. In addition, filter selection etc. become complicated,
The drawback was that it was much more difficult to handle.

Therefore, ion exchange fibers were devised to compensate for these drawbacks. Ion-exchange fibers have a large active surface area compared to resins, so they have a high reaction rate and a high adsorption ability for high-molecular-weight beneficial ions.

In addition, since it is fibrous, it has many advantageous features, such as increased flexibility in form, and low pressure loss due to its height, making it extremely easy to handle.

However, the ion-exchange fibers proposed so far are multifilamentary mixed fibers consisting of ion-exchange polymers and reinforcing polymers, and core-sheath composite fibers in which the reinforcing polymer is the core component and the ion-exchange polymer is the sheath component. fibers were used. In particular, ion exchange fibers based on multifilament composite fibers have excellent performance, but because they require an ion exchange polymer and a reinforcing polymer, their structure makes it impossible to make them extremely fine.

Another option is to introduce ion exchange groups into regular fibers, but this has the disadvantage that the number of exchange groups introduced is limited and the relative ion exchange performance is inferior to the above-mentioned fibers (in particular, the ion exchange rate is very low). .

In recent years, the needs for ion exchange, adsorption, and separation have become more precise, and accurate ion exchange, adsorption, and separation are required even from dilute materials. In response to this, in order to increase the active specific surface area and increase L/D in order to take advantage of the characteristics of fibers, it has become absolutely necessary to make the fiber diameter extremely fine.

In addition, by making it extremely fine, the specific surface area increases significantly, making it possible to introduce more ion exchange groups in the same process and increasing the exchange capacity per unit weight.

[Problems to be Solved by the Invention] An object of the present invention is to provide an ultrafine ion exchange fiber that can meet the needs for more advanced ion exchange and adsorption separation, and a method for producing the same.

[Means to solve the problem] That is, the present invention has the following configuration.

(1) Ultra-fine ion exchange fiber with a thread diameter of 0.00001 to 0.1 μm.

(2) The ultrafine ion exchange fiber described in (1) above, which is obtained by graft polymerizing an ion exchange group to a base material.

(3) The ultrafine ion exchange fiber according to (2) above, wherein the base material for introducing ion exchange groups is polyamide or polyester.

(4) The ultrafine ion exchange fiber according to (3) above, wherein the ion exchange group to be introduced is a carboxyl group.

(5) After removing the sea component of the multicore sea-island composite fiber, the diameter is O.
A method for producing ultrafine ion exchange fibers, which comprises graft polymerizing ion exchange groups to island components of O'0O01 to 0.1 μm.

(6) The method for producing an ultrafine ion exchange fiber according to (5) above, wherein the ultrafine fiber for introducing ion exchange groups is polyamide or polyester, and the ion exchange group is an acidic vinyl monomer having a carboxyl group.

The present invention will be explained in detail below.

The ultra-fine ion-exchange fiber of the present invention is produced by drawing a yarn spun as a multifilamentary sea-island composite fiber shown in FIG. It can be obtained by taking out ultrafine fibers and graft polymerizing them with heptamers having various ion exchange groups.

The proportion of island components in the multifilamentary sea-island type composite fiber, which is the base material of the ultra-fine ion exchange fiber of the present invention, is usually about 10 to 90%, but it is 20 to 80% taking spinning stability, stretchability, etc. into consideration.
degree is preferred. The number of islands is not particularly limited and is usually 10 or more, but from the viewpoint of economy and efficiency, a larger number is preferable, and in order to make the island part as thin as possible, at least 3
00 or more is preferable. The diameter of the multicore sea-island composite fiber immediately after spinning is necessarily 1 to 10 μm.

As the island component, homopolymers such as polyester and polyamide, or copolymers and blends thereof are preferably used.

The sea component is a polystyrene homopolymer.

Examples include, but are not limited to, a covalent combination of polystyrene and 2-ethylexyl acrylate, polyester (only when the island is polyamide), water-soluble polyester, nylon (only when the island is polyester), etc. .

It is preferable that the stretching ratio is usually about 2 to 10 times. This is because if the magnification is necessarily large, the uniformity of the thread diameter will be poor, and if it is small, the thread diameter will become thick. After stretching, the diameter of the multifilamentary sea-island composite fiber is about 0.2 to 5 μm. Sea components can be dissolved and removed by treating them with an appropriate method depending on the component, such as formic acid treatment for nylon, alkali treatment for polyester, trichlene treatment for styrene, and hot water treatment for water-soluble polyester. The components can be extracted directly as ultra-fine fibers. The thread diameter at that time is 0.00001~
It is less than 0.1 μm.

Since this fiber is made of polyamide, polyester, or a copolymer thereof, there are no problems with strength or chemical resistance.

Moreover, since it has an ultra-fine form, the single yarn strength tends to increase.

A heptamer having an ion exchange group is added to this ultrafine substrate by graft polymerization. The ion exchange group means an anion exchange group, a cation exchange group, a chelate group having chelate forming ability, and the like. Examples of anion exchange groups include strong basic anion exchange groups obtained by treating a haloalkylated product with a tertiary amine such as 1 to rimedylamine;
and isopropylamine, diethylamine, piperazine.

A weakly basic anion exchange group obtained by treatment with a secondary or lower amine such as morpholine is preferably used.

Cation exchange groups include sulfonic acid groups, bosphonic acid groups,
Carboxylic acid groups and the like are preferably used.

The chelate group may be any chelate-1 to chelate-forming functional group, but a functional group having an iminodiacetic acid group or iminodipropion-11 is preferably used.

The method of grafting the heptadome having these components is arbitrary and is not necessarily limited to one method. A typical method is to introduce a carboxylic acid type cation exchange fiber into a nylon or polyester substrate through solution grafting of an acidic vinyl monomer having a carboxyl group under a redox catalyst.

Specific examples of acidic vinyl monomers having a carboxyl group include acrylic acid, maleic acid, methacrylic acid, itaconic acid, butenetricarboxylic acid, etc., but a mixture of acrylic acid and methacrylic acid is graft polymerized most efficiently. Ru.

Examples of the form of the fibers used include short fibers, filament yarns, felt, woven fabrics, non-woven fabrics, knitted fabrics, fiber bundles, strings, paper, etc., as well as aggregates and cut products thereof. be able to.

Furthermore, the grafting reaction may be performed either before or after imparting these forms.

The ultrafine ion exchange fiber of the present invention softens water.

Desalination of water and seawater, removal of harmful metals, separation and recovery of useful heavy metals, decolorization and desalination of various sugar solutions, purification and separation of antibiotics and pharmaceuticals, purification and separation of amino acids.

It is used in fields where ordinary ion exchange resins are used, such as iodine purification, formalin purification, and water removal. Pigments such as pigments, proteins, enzymes, colloidal substances such as bacterial cells, hydrogen sulfide, halogenated gases, ammonia, etc.
It can also be used to adsorb and remove basic residues such as amines. The use of Torineri in nuclear power applications is effective,
Atomic) J-related water and wastewater, specifically nuclear power plant condensate, fuel pool water, core water, desalination equipment backwash wastewater, steam generation blow water, wet water separator drain water and xeviity water, and suppression. Suitable for treating pool water, etc.

In addition, it is used in a wide range of applications, including the production of ultrapure water, removal of mutagens from tobacco, and catalysts for acid/base catalytic reactions.

Examples are shown below, but the present invention is not limited thereto.

[Example] Example 1 Using nylon 6 for the island component and polystyrene for the sea component,
After melt composite spinning was performed at 285°C so that there were 450 island components, it was hot stretched to 4 times.

The multifilamentary sea-island type composite fiber was immersed in trichlene at air temperature to dissolve and remove sea components, shaken for 4 hours, and then washed with previously stored water. At that time, the fiber diameter was measured using a scanning electron microscope and was found to be 0.0001 μm. The threads were pulled together to make cut fibers, and placed in the reaction tank using acrylic r! l:L
1.5 parts, methacrylic acid 4.5 parts, anthene persulfate 0.
1 part - Commercially available reducing agent (manufactured by Mitsubishi Kasei Corporation: trade name Super Light C> O.

Add an aqueous solution consisting of 4 parts and 93.5 parts of water at a bath ratio of 1:1.
0 and allowed to react at 80°C for 10 minutes. This was washed with water to form ultrafine cation exchange fibers having carboxylic acid groups. The diameter of the ultrafine cation exchange fiber was measured using a scanning electron microscope, and there was almost no change from before the reaction.

Next, 1.2 g of this cut fiber was placed in 50 ml of 0.1N thorium hydroxide, shaken for 2 hours, and the ion exchange capacity was measured by accurately measuring 5 d.

In addition, after soaking this cut fiber in ion-exchanged water, centrifugally dehydrate it for 5 minutes in a household centrifugal dehydrator to remove surface water, immediately measure the weight ffi (W>), and thoroughly dry it. The weight (Wo> was measured, and the water content was determined from the following formula.

Water content = (W-Wo>/W.

The results are shown in Table 1.

In addition, this ultra-fine ion exchange fiber was treated with NaOH using 1N-NaOH.
It was converted into a mold, washed with ion-exchanged water, and then completely dried in a dryer. A water softening experiment was conducted in which 10 of the fibers were sampled, placed in 2'fJ of drinking water, stirred with a stirrer, and 100 mN were sampled over time to measure the hardness (Ca2''+MC]2+).

The results are shown in Table 2.

The method for measuring hardness is as follows.

(Chelate titration) Sample water 100m, Q, pH1O buffer 2m, f
) 0.01M VIQC121m, Q, EBT reagent 3
) and titrate with EDTA solution to calculate.

EBT reagent: EBT O, 5g, hydroxylamine hydrochloride4. sg, ethanol 100m, QE DTA
: CH14N2 N aOB @ 2 H20 Example 2 The fibers, chemicals, temperature, etc. used were all the same as in Example 1,
The reaction time was changed to 60 minutes to obtain ultrafine cation exchange fibers, and the ion exchange capacity and water content were measured.

The results are shown in Table 1.

Comparative Example A normal nylon thread (fiber diameter 10 μTrL) was subjected to the same reaction as in Example 2, and the exchange capacity and water content were measured.

The results are shown in Table 1.

Further, a water softening experiment was conducted under the same conditions as in Example 1 using this ion exchange fiber.

The results are shown in Table 2.

From these results, it was found that ultrafine ion exchange fibers were obtained by graft polymerization reaction, that the ion exchange rate was very high, and that the fibers were extremely excellent as ion exchange fibers as they could introduce many ion exchange groups.

Table 1. Characteristic unit of each fiber: (ppm) *Value of raw water is 46 ppm [Effect of the invention 1 The ultra-fine ion-exchange fiber of the present invention has an unprecedented ultra-fine fiber diameter and has a large specific surface area. It has a very high ion exchange rate, and has a great effect on ion exchange and adsorption in dilute conditions.

It is also very easy to give different shapes and can be used in fields that could not be applied to conventional fats.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a multicore sea-island composite fiber used in the ultrafine ion exchange fiber of the present invention. Patent applicant Toshi Co., Ltd. Figure 1

Claims (5)

[Claims] (1) Ultra-fine ion exchange fiber with a thread diameter of 0.00001 to 0.1 μm. (2) The ultrafine ion exchange fiber according to claim (1), which is obtained by graft polymerizing an ion exchange group to a base material. (3) The ultrafine ion exchange fiber according to claim (2), wherein the base material for introducing ion exchange groups is polyamide or polyester. (4) The ultrafine ion exchange fiber according to claim (3), wherein the ion exchange group to be introduced is a carboxyl group. (5) The sea component of the multifilamentary sea-island composite fiber is removed to reduce the diameter to 0.
1. A method for producing ultrafine ion exchange fibers, which comprises graft polymerizing ion exchange groups to island components of 00001 to 0.1 μm. (6) The method for producing ultrafine ion exchange fibers according to claim (5), wherein the ultrafine fibers for introducing ion exchange groups are polyamide or polyester, and the ion exchange groups are acidic vinyl monomers having carboxyl groups.