JPS6260127B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water removal filter for liquids in which fibers containing specific water-swellable fibers are formed into a cylindrical shape.

In recent years, highly water-swellable and water-insoluble polymers (hydrogel) are being applied to a wide range of fields such as diapers, sanitary products, soil improvement materials, and soft contact lenses.

On the other hand, there is a strong demand for reusing or extending the lifespan of liquids that are not miscible with water, such as organic solvents and lubricating oils, by removing water that is mixed in with them. For example, it is used in granules and some inorganic salts of silica gel and zeolite. However, although it is possible to remove some water with such inorganic salts, their water removal ability is extremely low, and furthermore, such inorganic salts have the inherent defect that they are mixed into purified liquids to some extent.
As a result, its field of use had to be restricted.
In addition, some attempts have been made to use fibers that have some degree of hygroscopicity or water absorption, such as natural pulp.
However, its water removal ability was extremely low, and it was of little practical use.

Therefore, the present inventors focused on the instantaneous large amount water absorption ability or water retention ability of the water-swellable polymer (hydrogel), and investigated the possibility of using such hydrogel as a water removal material for liquids. . However, when using hydrogels in particulate form,
Although it has excellent water absorption performance, it has been found that it has the disadvantage that it swells instantaneously and causes clogging, making it necessary to stop water removal treatment in an extremely short period of time. Therefore, in order to improve such clogging, we tried using a hydrogel with a fibrous form.
Although it is possible to extend the water removal treatment time to some extent compared to granular hydrogels, it is still not possible to overcome the problem of clogging due to swelling and settling of the fibers, and the water absorption performance cannot be fully utilized. Ta. Therefore, the inventors of the present invention proposed the following patent application:
As proposed in Specification No. 15786 (Japanese Unexamined Patent Publication No. 106539/1983), water-swellable fibers having a multiphase structure of an outer layer of hydrogel and an inner layer of AN polymer and/or other polymers, or It has been found that by using a mixture of these fibers and other fibers, water removal treatment can be carried out for a long time without the fibers becoming sag, and the water absorbing performance of the hydrogel can be fully demonstrated.

Under such circumstances, the inventors of the present invention, based on such knowledge, conducted intensive studies to provide a cylindrical (wind) filter as a water removal material for liquids using the above-mentioned specific fibrous hydrogel. A filter is formed by forming a cylindrical fiber aggregate containing water-swellable fibers, a part of which is composed of hydrogel, and the remainder of which is composed of AN polymer and/or other polymers. The present invention was achieved by discovering that water removal treatment can be performed for a long time without problems of bypass flow due to density unevenness in the length direction or fatigue of the fibers, and that the water absorption performance of hydrogel can be fully demonstrated. .

That is, the main object of the present invention is to provide a novel water removal filter for liquids that is easy to mold and has excellent water removal ability. To provide a water removal filter which is free from spots and whose winding density and cylindrical thickness can be arbitrarily adjusted.

Another object of the present invention is to have excellent water absorption and swelling performance, not to cause settling or clogging, and to be able to be used for a long time without replacement.
Another object of the present invention is to provide a water removal filter for liquids that does not mix water removal material into purified liquids as is the case when granular inorganic salts are used, and which is easy to replace. It will become clear from the detailed description of the present invention provided below.

The above-mentioned object of the present invention is that at least a part of the fiber outer layer is made of hydrogel, and the remaining part is made of hydrogel.
By winding a fiber aggregate containing water-swellable fibers made of AN polymer and/or other polymers into a cylindrical shape, can be achieved advantageously.

Here, the water-swellable fiber according to the present invention refers to a hydrogel layer that exhibits water absorption and swelling performance, and an AN-based polymer and/or that shares fiber physical properties such as strength and elongation.
It is also a general term for fibers that have a multilayer structure with other polymer layers. The degree of water swelling of such water-swellable fibers is
It is desirable that the amount is 2 c.c./g or more, more preferably within the range of 2 to 350 c.c./g, and the proportion of the hydrogel layer is appropriately set in consideration of water absorption and swelling performance and fiber physical properties. Although it is difficult to define it unambiguously, it is desirable that it be approximately 55% or less, more preferably within the range of 5 to 40%, based on the total volume of the fiber when dry. Furthermore, the degree of water swelling of fibers is also influenced by the crosslinking density, and -COOX (X: alkali metal or
Although not controlled solely by the amount of salt-type carboxyl groups represented by NH ₄ ), the amount of salt-type carboxyl groups is generally 0.1 to 4.0 mmol/g, more preferably 0.5
A content in the range of ~3.5 mmol/g is desirable in terms of water swelling degree, fiber properties, flexibility, etc.

The above-mentioned AN-based polymer is a general term for polymers containing 30% by weight or more, preferably 50% or more of AN, and is an AN homopolymer or a polymer containing AN and at least 1% by weight.
copolymers with other ethylenically unsaturated compounds of the species,
Alternatively, graft polymers of AN and other polymers such as starch, polyvinyl alcohol, etc. can be mentioned, but as long as the above AN content is satisfied, AN
It is also possible to use a mixed polymer of this polymer and other polymers such as polyvinyl chloride, polyamide, polyolefin, polystyrene, polyvinyl alcohol, cellulose, etc.

In addition, the fiber aggregate containing water-swellable fibers is a general term for fibers in a form that can be wound into a cylindrical shape in a middle tube, such as yarn, web, woven fabric, knitted fabric, etc. It goes without saying that it refers to mixed products of water-swellable fibers and other fibers, but also refers to single products containing these water-swellable fibers and/or mixed products with fiber aggregates consisting only of other fibers. ,
The yarns described in the present invention include monofilament and multifilament yarns, as well as worsted yarns, double-spun yarns, cotton-spun yarns, woolen yarns, open-end yarns, and the like. In addition, other fibers include natural fibers such as cotton and wool; semi-synthetic fibers such as rayon and Kyupura; synthetic fibers such as polyvinyl alcohol, polyvinyl chloride, polyamide, polyester, and polyacrylonitrile. The mixing ratio of such other fibers can be appropriately selected depending on the degree of water swelling of the water-swellable fibers, the water removal performance of the final filter, etc., but it is generally used at a ratio of 95% by weight or less. Ru. Furthermore, the degree of water swelling of a fiber aggregate containing such water-swellable fibers can be appropriately set depending on the water content in the liquid to be treated, the viscosity of the liquid, etc., but it is difficult to define it unambiguously. Approximately 1~
It is desirable that the amount is within the range of 200 c.c./g, more preferably 2 to 100 c.c./g. Furthermore, it is preferable to use thread-shaped fiber aggregates from the viewpoint of formability, etc., and by using so-called bulky threads as such threads, stiffness of the fibers, sagging, etc.
This is desirable because the bulkiness and the like are significantly improved, thereby significantly improving the water removal ability of the final filter.

Furthermore, the fiber aggregate containing water-swellable fibers may be introduced into a hydrogel layer in the form of starting fibers or fiber aggregates, or may be formed by a fiber aggregate containing hydrogel-formable fibers. A hydrogel layer may be introduced in the form of a filter.

Regarding the hydrogel formation method, there are no restrictions and it can be adopted as long as a hydrogel layer can be introduced into at least a part of the outer layer of the fiber, but it is possible to use a hydrogel formation method that is made of a polymer having a specific composition such as a cross-linking reactive monomer. As an industrially advantageous method for producing fibers incorporating a hydrogel layer having desired water swelling performance through a hydrolysis treatment process alone, without using fibers as a starting material or subjecting them to crosslinking treatment in advance. For example, the following means can be suitably employed. That is, in JP-A-Sho, AN-based fibers are treated with a highly concentrated aqueous alkali metal hydroxide solution of 6.0 mol/1000 g or more on a fiber aggregate containing AN-based fibers or a filter made of the fiber aggregate. 53-80493, or 0.5mol/
Sodium chloride, mirabilite, at a concentration of 1000g or more solution
Patent application filed in 1973 for the action of a low concentration alkali metal hydroxide aqueous solution coexisting with an electrolyte salt such as sodium nitrate
Examples include the method described in Japanese Patent No. 47974.

Regarding the form and winding density of the filter formed into a cylindrical shape by winding the fiber aggregate containing the water-swellable fibers according to the present invention into a middle tube,
Although it is difficult to define it unambiguously as it needs to be varied depending on the type of liquid to be treated, viscosity, etc., the ratio of the diameter and height of the cylinder is generally 1:0.5 to 1:0.5.
20, more preferably 1:1 to 10, and the rolling density is approximately 0.1 to 0.6 g/cm ³ , more preferably 0.15 to 0.4 g/cm 3
It is desirable to be in the range of cm ³ .

Note that such a filter may be used by supplying the liquid to be treated from either the outer or inner surface of the cylinder, but the liquid to be treated may be supplied from the outer surface of the cylinder and the purified liquid from the inner surface. The usage form in which the fibers are taken out from the fibers has a larger surface area in contact with the liquid to be treated, which can improve treatment efficiency.
Therefore, the inner tube, which is a support for winding the fiber aggregate, also plays the role of maintaining the shape of the filter during water removal treatment, and must not be corroded or dissolved by the liquid to be treated. However, any thickness and material can be used as long as it satisfies these requirements. In addition, the inner cylinder must have a plurality of holes for the purified liquid to pass through, and the plurality of holes must prevent unevenness in liquid flow, liquid passage pressure, etc. Needless to say, it is desirable that the holes be evenly drilled throughout the middle cylinder to prevent this from occurring.
Further, the shape of the cylindrical water removal filter according to the present invention is preferably a so-called hollow cylinder shape, but it can also be formed into a hollow truncated cone shape if desired by selecting the winding method, the shape of the inner cylinder, etc. .

Here, the liquids to which the water removal filter recommended in the present invention is applied are those that are liquid under water removal treatment conditions and undergo phase separation from water (even if some mutual dissolution occurs, phase separation does not occur). It is a general term for things. Those having such properties include petroleum hydrocarbons such as petroleum ether, pentane, hexane, heptane, and petroleum benzene; alicyclic saturated hydrocarbons such as cyclohexane and cyclooctane; and aliphatic non-hydrocarbons such as 1-octene and cyclohexane. Saturated hydrocarbons; aromatic hydrocarbons such as benzene, toluene, xylene, and styrene; tetrachlorethylene, methylene chloride, chloroform,
Halogenated aliphatic hydrocarbons such as carbon tetrachloride; spindle oil, refrigerating machine oil, dynamo oil, turbine oil, machine oil, cylinder oil, marine engine oil, gear oil, cutting oil, hydraulic oil, compressor oil, etc. Examples include lubricating oils.

The water removal filter for liquids according to the present invention described above has no density unevenness in the length direction of the cylinder, and has a winding density,
It can be molded industrially with industrial advantages such as the ability to adjust the thickness of the cylinder, etc., and prevents settling, clogging, bypass flow, or mixing of water removal material into purified liquid during water removal treatment. A notable advantage of the present invention is that it exhibits outstanding water removal ability over a long period of time without any problems.

In addition, the filter according to the present invention is extremely easy to install and replace in water removal treatment equipment, and has great operational advantages.Furthermore, with the advent of such a filter, liquids that were conventionally discarded can be regenerated and reused. It is of great significance that this path was paved.

In order to further facilitate understanding of the present invention, Examples are described below, but the gist of the present invention is not limited in any way by the description of these Examples.
It should be noted that all percentages and parts described in the Examples are based on weight unless otherwise specified.

The degree of water swelling and the amount of salt-type carboxyl group (-COOX) described in the Examples were measured or calculated by the following method.

(1) Degree of water swelling (cc/g) The sample was immersed in pure water, kept at 25℃ for 24 hours, then wrapped in nylon filter cloth (200 mesh) and placed in a centrifugal dehydrator (3G x 30 minutes, where G is gravity). (acceleration) removes water between fibers. Measure the weight of the sample prepared in this way (W ₁ g). The sample is then dried in a vacuum dryer at 80° C. to a constant weight and weighed (W ₂ g). From the above measurement results, it was calculated using the following formula. Therefore, the actual water swelling degree is a numerical value indicating how many times the weight of the fiber can absorb and retain water.

(Water swelling degree) = W ₁ - W ₂ /W ₂ (2) -COOX group amount (m mol/g) Approximately 1 g of a sufficiently dried sample was accurately weighed (Xg), and
After adding 200 ml of water, a 1N aqueous hydrochloric acid solution was added while heating to 50°C to adjust the pH to 2, and then a titration curve was determined using a 0.1N aqueous sodium hydroxide solution according to a conventional method.
The amount of caustic soda aqueous solution consumed by carboxyl groups (Yc.c.) was determined from the titration curve. From the above measurement results, it was calculated using the following formula.

(-COOX group amount)=0.1Y/X In addition, when polyvalent cations are included, it is necessary to determine the amount of these cations by a conventional method and correct the above formula.

Example 1 AN-based fiber consisting of 90% AN and 10% methyl acrylate (single fiber fineness: 5 ^d , fiber length: 76
mm) 40% and the AN-based fiber (however, single fiber fineness;
7 ^d ) A 30% aqueous solution of caustic soda was uniformly spread onto a 1/8 meter count woolen regular yarn made of 60% yarn, so that 20% of the yarn adhered to the yarn. Next, this thread was placed in an autoclave, heated for 5 minutes in saturated steam at 107°C, and the residual alkali was washed away with water, and dried to produce a white to slightly yellow water-swellable fiber thread (). did.

The fibers obtained by decomposing the yarn () did not dissolve in water, and when squeezed in a swollen state with water, the AN polymer core remained and only the outer layer of the treated fibers was hydrogelated. This was confirmed. The fiber contained 0.4 mmol/g of -COONa groups and had a water swelling degree of 6 c.c./g.

A filter was prepared by winding up the thread (2) into a middle cylinder having a diameter of 30 mm and a length of 247 mm at a density of 0.25 g/cm ³ to a diameter of 70 mm.

Turbine oil (white cloudy state) mixed with 0.2% water is mixed with a water remover equipped with this filter.
was connected to a container containing oil, and a water removal operation was performed so that the oil circulated through the water remover at a rate of 1/min.

During this period of operation, there was no pressure increase due to clogging, and the operating conditions were good, and after the oil to be treated passed through the water remover twice or more, the turbine oil was transparent (moisture content 0.02% or less). It was confirmed that water removal was complete.

In addition, the hydrolysis time was changed (heated for 1 hour), except for the yarn (), which was made of fibers with a water swelling degree of 314 c.c./g and no AN polymer core remaining. When the thread was used to remove water, the pressure suddenly increased due to clogging 5 minutes after the start of operation, and the operation could not be continued.

Example 2 Two-component bonded AN-based composite fiber (manufactured by Nippon Exlan Kogyo Co., Ltd., monofilament fiber strength: 6 ^d , Varicut)
A 2/5 meter count worsted bulky yarn consisting of 60% and 40% AN fiber (5 ^d x Balikat, bulky) described in Example 1 was treated with alkali according to the recipe described in Example 1 A thread () made of water-swellable fibers was produced.

The fibers obtained by decomposing this thread () do not dissolve in water,
The AN polymer core remained and had a water swelling degree of 6 c.c./g.

A filter was made from this thread () in the same manner as in Example 1, and the amount of water removed was measured to be 340g.
It was confirmed that water was absorbed and removed. The amount of water removed (g) was measured during the water removal treatment operation described in Example 1. Even after the oil to be treated passes through the water remover twice or more, water is continuously added to the oil to be treated until the treated oil no longer becomes transparent. It was found by adding .

Example 3 30% cotton, AN-based fiber described in Example 1 (however,
1.5 ^d × 38 mm) 30% and the AN fiber (however, 2 ^d
x 38 mm, bulky) made of 40% cotton spun bulky yarn of 2/30 meter count was treated with alkali according to the recipe described in Example 1 to create a yarn containing water-swellable fibers. A filter was made.

The amount of water removed by this filter was 300g.

Incidentally, the water swelling degree of the yarn (2) was 4.5 g/cc.

Example 4 The AN-based composite fiber described in Example 2 (however, 2.5 ^d ×
76mm), uniformly spread a 10% caustic soda aqueous solution containing 20% sodium nitrate to make it adhere to 30%.
Next, this fiber is placed in an autoclave,
After heating in saturated steam at 115° C. for 10 minutes, residual alkali was removed by washing with water and dried to produce white to slightly yellow water-swellable fibers. This fiber still has an AN-based polymer core, and has a -
It contained COONa groups and had a water swelling degree of 85 c.c./g.

10% of this fiber and polyester fiber (3 ^d × 76
A woolen blended yarn () with a count of 1/8 m from 90% mm) was produced.

The amount of water removed by a filter made of this thread (winding density: 0.2 g/cm ³ ) was 250 g.

Claims (1)

[Claims] 1 A plurality of fiber aggregates containing water-swellable fibers in which at least a part of the fiber outer layer is composed of a hydrophilic cross-linked polymer and the remainder is composed of an acrylonitrile polymer and/or other polymers. A water removal filter for liquids that is wound into a cylindrical shape around a hollow cylinder.