JPS58462B2 - Ion Kokanseisenjiyoubutsunoseihou - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing a novel ion-exchangeable fiber.

Ion exchange resins obtained from copolymers of acrylic acid esters or methacrylic esters and divinylbenzene have high exchange capacity and excellent performance as weakly acidic cation exchange resins and weakly basic anion exchange resins. It is widely praised as a mainstream ion exchange resin along with benzene-based resins.

However, there are limits that cannot be achieved with granular materials.

In order to overcome this limitation and obtain performance such as faster reaction rate and easier operability, it is an effective method to form the resin into a fiber form.

As a method for producing such an ion-exchangeable fiber, (1)
It is required that a highly uniform fiber shape can be imparted, and (2) the degree of crosslinking can be easily and reproducibly controlled over a wide range, and it is desirable to have a porous structure in order to have a larger specific surface area.

When a porous structure is provided, it is fundamentally required that (3) the porosity be easily controlled.

In other words, the requirements in (1), (2), and (3) above correspond to particle size, degree of crosslinking, and porosity, which respectively determine the basic properties of ion exchange resins, and as with granular materials, fibers This is naturally required in the case of articles as well.

However, at present, there is no method that satisfies these points.

The most important reason for this is thought to be that it is extremely difficult to form a molded product, particularly a fibrous product, directly from a monomer as in the case of resin.

The present inventors have conducted extensive research to eliminate these drawbacks, and as a result, have arrived at the present invention.

That is, the present invention essentially consists of acrylic esters and/or
Or, a monomer mixture consisting of a methacrylic acid ester, divinylbenzene, and a polymerization initiator, containing 0.3 to 40% divinylbenzene based on the total monomer amount, is swollen but soluble at least at the polymerization temperature. Added to the raw material fiber without fiber, the swelling rate of the fiber is 30% by volume.
Polyacrylic ester and/or polymethacrylic ester are polymerized while being absorbed into the fibers as above, and then the raw fiber components are decomposed or dissolved and removed, and the resulting divinylbenzene crosslinks the polyacrylic ester and/or polymethacrylic ester. This is a method for producing a porous ion-exchangeable fibrous material, which is characterized by introducing ion exchange groups into the fibrous material.

According to the method of the present invention, the obtained fibrous material consists of (a) a constituent essentially consisting of a polyacrylic ester crosslinked with divinylbenzene and/or a polymethacrylic ester crosslinked with divinylbenzene; Contains no raw fiber components.

However, it is natural that other monomers may be added to form a three-dimensional or more dimensional copolymer, as long as the properties are not affected.

(b) Fineness, fiber cross-sectional shape, fiber length, etc. can be changed depending on the form of the raw material fiber used.

(c) The degree of crosslinking can be easily adjusted by adjusting the content of divinylbenzene.

(ii) Porosity can be controlled by the ratio of monomer components added to the raw material fibers.

It has the following characteristics.

The acrylic ester or methacrylic ester used in the present invention is preferably an ester with an alkyl group having 5 or less carbon atoms or a hydroxyethyl group; This is not preferred in terms of ease of introducing the group, cost, etc.

The combination of monomers used in the present invention is essentially two components, acrylic ester-divinylbenzene or methacrylic ester-divinylbenzene, or three components, methacrylic ester-acrylic ester-divinylbenzene, but special A small amount of a monomer effective for the purpose, such as a hydrophilic monomer such as acrylic acid amide or methacrylic acid amide, may be used in order to impart some hydrophilicity to the product.

Furthermore, the content ratio of divinylbenzene to all monomers is important in determining the degree of crosslinking of the product.

That is, the degree of swelling and ion exchange properties of the product are determined by the usage rate of divinylbenzene.

Generally, the amount of divinylbenzene used varies depending on the use, but is 0.3 to 40% based on the total monomer components.

The polymerization initiator used in the present invention is preferably one that is soluble in the above monomer mixture and has an activation temperature of 50 to 130°C. Examples thereof include benzoyl peroxide, acetyl peroxide, lauroyl peroxide, and cumene. Examples include hydroxy peroxide, tertiary butyl hydroxyl peroxide, azobisisobutyronitrile, and the like.

These can be used alone or in combination.

The appropriate amount to be used is several percent or less of the weight of the monomer.

In order to effectively penetrate the above-mentioned components into the raw material fibers, a soluble fiber solvent can be used in combination with the mixture in an amount that does not dissolve the raw material fibers.

On the other hand, if these mixtures cause the raw material fibers to excessively swell or dissolve, a chemical that is soluble in these mixtures and has poor solubility in the raw material fibers may be added or used in combination.

The mixture of the above components is hereinafter abbreviated as a monomer mixture.

The raw material fibers used in the present invention are firstly fibers that swell but do not dissolve in the monomer mixture at least at its polymerization temperature, and secondly, the monomer mixture is polymerized within the raw fibers and then decomposed or dissolved. Requires fibers that can be removed.

More specifically, the first condition is that fibers that can be swollen by 30% by volume or more by the monomer mixture at the polymerization temperature must be used as raw fibers.

In this case, if the swelling ratio of the fiber is less than 30% by volume, the absorption of the monomer mixture after application is insufficient, and polymerization outside the fiber tends to occur, and the distribution of the polymer formed within the fiber. It also tends to become non-uniform, making it impossible to achieve the purpose of the present invention.

If the swelling ratio is too high, the raw fibers will be close to a dissolved state, and strong adhesion will occur between adjacent fibers, making it impossible to remove this adhesion after polymerization.

Therefore, it is preferable to select a monomer mixture composition and a combination of raw material fibers that have a swelling ratio in the range of 50 to 400% by volume.

The swelling rate can be determined by introducing short cut raw material fibers into a large excess monomer mixture and observing the volume increase rate of the raw material fibers after polymerization under the polymerization temperature using a microscope.

Examples of fibers that may satisfy the first condition include acrylic fibers (including modacrylic fibers), polyethylene terephthalate fibers, nylon 6, and nylon 66.
, diacetate fiber, triacetate fiber, post-acetylated rayon, polyurethane fiber (spandex), etc.

The second condition is that it is necessary to use fibers that are either raw materials with good solvents or that can be relatively easily decomposed by chemicals.

In general, decomposition and removal using chemicals is easier to completely remove than extraction and removal using a solvent.

From this point of view, the raw material fibers are preferably fibers obtained from polymers in which the main chain is formed through easily decomposed groups such as ester, urethane, urea, and amide bonds.

Among the fibers having such properties, diacetate fibers and triacetate fibers have the property of swelling well in a monomer mixture, and the mixture is swelled in a fiber polymer with a
Even if a large amount of 300% is absorbed, there is little or very little change in the fiber length. Therefore, absorption of the monomer mixture and polymerization operation are easy, and raw fibers can be easily removed by decomposition or dissolution after polymerization. Since it has certain advantages, it is particularly preferable as a raw material fiber.

The process from applying the monomer mixture to the raw fibers to polymerization involves immersing the raw fibers in the monomer mixture to sufficiently swell them, wiping off the excess monomer mixture adhering to the outside of the fibers, and then immersing them in an atmosphere at a temperature that allows polymerization. A method in which a monomer mixture is applied to the fiber within a range that can be absorbed by the raw material fiber, and then polymerization is started after the monomer mixture has been completely absorbed in a heated atmosphere or almost simultaneously with the absorption. It can be broadly divided into

In the case of the first method, the monomer mixture at the time of soaking the raw fibers is heated using a polymerization initiator with a relatively high activation temperature to the extent that substantially no overlapping occurs and to facilitate swelling. It is necessary to use it in

Generally, this method is suitable when monofilaments or fine filament bundles are used as raw material fibers.

In the second method, it is preferable to use fibers that swell well with the monomer mixture and to apply the monomer mixture quickly at low temperatures so as to slightly suppress the swelling of the fibers during application.

In particular, when using fiber aggregates such as tow, cloth, and thread, avoid bulky materials and use materials with small fiber gaps.
Alternatively, it is preferable to absorb and polymerize the monomer mixture under tension or compression to reduce the fiber gaps.

In both of the above methods, the heating atmosphere is preferably in a heating medium that is below the boiling point of the monomer mixture and does not cause evaporation or diffusion of the monomer mixture, and specifically, it is best to use heated water or heated water containing inorganic salts. However, it may also be placed in a glass container and heated indirectly from the surroundings.

In addition, when using raw material fibers that shrink significantly due to the absorption of the monomer mixture, the fibers must be kept under tension so as not to shrink by more than a certain percentage, preferably 50% or more relative to the base material, so that the absorption and polymerization of the monomer mixture can occur. need to be done.

If the fibers are adhered to each other when the monomer mixture is polymerized within the raw fibers, it is necessary to remove the adhesion prior to the decomposition or dissolution step.

When using cloth, multifilament yarn, spun yarn, tow, etc. as the raw material, adhesives can be removed by passing the tow, filament bundle, spun yarn, etc. through a pair of rollers under pressure the necessary number of times, or by passing the tow, filament bundle, spun yarn, etc. When using yarn or the like as short fibers, the adhesive is removed by cutting the fibers into pieces of several mm or less and passing them through a mixer or a pulp beater.

Removal of raw fiber components by the dissolution method can be carried out using a Soxhlet extractor or the like using a solvent for the fibers.

Examples of combinations of raw fibers and fiber solvents suitable for the dissolution method include dimethylformamide for acrylic fibers;
dimethylacetamide or dimethylsulfoxide, dimethylformamide, dimethylacetamide, dimethylsulfoxide or acetone for modacrylic fibers,
Acetone for diacetate fibers, methylene chloride or 1,2-dichloroethane for triacetate fibers,
In the case of polyurethane, mention may be made of dimethylformamide, dimethylacetamide or dimethylsulfoxide.

Removal of raw fiber components by the decomposition method can be applied to polyethylene terephthalate fibers, diacetate fibers, triacetate fibers, post-acetated rayon, polyurethane fibers, etc., and is generally carried out by using a mineral acid, particularly sulfuric acid or an aqueous sulfuric acid solution.

When using sulfuric acid, it can be easily carried out by immersion at room temperature, but generally a 20-90% sulfuric acid aqueous solution is used, preferably heated to 60-100°C to easily achieve the purpose. can be reached.

In the case of polyurethane fibers or polyethylene terephthalate fibers, the decomposition can be carried out using an aqueous IJ solution, but it is more preferable to use sulfuric acid or an aqueous sulfuric acid solution in terms of processing time and economy.

In the case of the decomposition method, the fibers are purified by washing with an aqueous alkaline solution, water, or a solvent to remove decomposition products (for example, terephthalic acid in the case of polyethylene terephthalate fibers produced by the sulfuric acid method), if necessary.

The porous polyacrylic acid ester fibers and temporary or polymethacrylic acid ester fibers crosslinked with divinylbenzene obtained in this way can have their crosslinking degree, porosity, fiber morphology, etc. arbitrarily changed, and the ion exchange groups can be changed. By introducing it, a very advantageous ion exchanger can be obtained.

In principle, the conditions for the corresponding ion exchange resin can be applied to the introduction of the ion exchange group as they are.

That is, to give a typical example, in order to obtain a weakly acidic cation exchanger, first, an ester group may be hydrolyzed to introduce a carboxyl group.

This hydrolysis reaction can be carried out in the presence of a strong acid or strong alkali, but in general, the efficiency of the hydrolysis reaction is better when an alkali is used, and furthermore, the reaction is carried out under reflux using an alcoholic KOH or NaOH solution. By doing so, it is possible to introduce a carboxyl group close to the theoretical value.

Next, by reacting with polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine, or partially alkylated derivatives of these amines, the ester group is amitolyzed by these amines to form a weak base. A fibrous material capable of exchanging sexual anions is obtained.

Further, by reacting with hydrazine or hydroxylamine, a fibrous material having special ion exchange groups characterized by acid hydrazide, amidoxamic acid groups, etc. can be obtained.

Parts in the following examples mean parts by weight.

Example 1 A monomer mixture was prepared consisting of 90 parts of ethyl methacrylate, 1.5 parts of divinylbenzene (a product with a purity of 58% containing ethyl styrene as the main impurity was used, the same applies hereinafter), and 1.0 part of azobisisobutyronitrile. 20-22
It was kept at ℃.

The raw material fiber is diacetate filament yarn with a single fiber fineness of 4.1 denier, a circumference of 180 cm, and a winding amount of 200 g.
This skein prepared as a skein is immersed in the monomer mixture liquid, and this is squeezed with a sponge roll to add 240 g (120% owf) of the monomer mixture to the skein.
After adhesion, both ends were fixed with metal rods and immersed in a saturated aqueous solution of Glauber's salt kept at 70°C.

After 1 to 2 minutes of immersion, the monomer mixture adhering to the fiber gaps was absorbed into the fibers, and then polymerization started while generating nitrogen gas due to the decomposition of azobisisobutyronitrile, and the polymerization was completed after 3 hours. .

After the polymerization was completed, the fibers were lightly adhered to each other to the extent that they could be easily loosened by hand, resembling lightly glued skein yarn.

Cut this into 1.5 mm using a guillotine cutter,
The fibers were passed through a commercial mixer with 50 times the fiber weight of water to remove intrafiber adhesion, and the water was removed using a 120-mesh mesh to recover the fibers.

The total amount of recovered fibers was heated to 70°C and 50% by weight of sulfuric acid 101
The diacetate of the raw fiber is decomposed by immersing it in water for 4 hours, and then the decomposed products and sulfuric acid of the raw fiber are removed by collecting it on a 120-mesh sieve and washing with running water. When dried under reduced pressure, 224 g of polyethyl methacrylate fibers crosslinked with divinylbenzene were obtained.

When comparing the thus obtained filaments with those before removing the raw fibers and observing them using a 100x microscope photograph, no significant difference was observed in the fiber side surfaces and cross sections, but BE
The surface area measurement result using the T method was 29.7 m2/g, which was clearly found to be more porous than the 0.31 m2/g before removing the raw material fibers.

This material is referred to as fibrous material A.

30 g of fibrous material A, 200 g of xylene, and 500 g of pentaethylene hexamine were placed in a flask 17, and treated under reflux for 6 hours. After sufficient removal, it was made into an OH type with 2N caustic soda solution and washed with deionized water until sodium ions disappeared.

The obtained fibrous material had the ability to neutralize 6.7 meq of hydrochloric acid per 11 dry weight.

Example 2 30 g of fibrous material A and 500 g of ethylenediamine were placed in a flask No. 11 and reacted at 100° C. for 5 hours, followed by treatment in the same manner as in Example 1, resulting in a fibrous material with a hydrochloric acid neutralization capacity of 6.2 meq 7 g. Obtained.

Example 3 In Example 1, the raw material fiber had a single fiber fineness of 10.2.
Using a denier triacetate filament system (trade name: Soalon, manufactured by Mitsubishi Acetate Co., Ltd.) with a circumference of 180 cm and a winding amount of 200 g in a 0-skein state, the amount of monomer mixture attached was set to 2451, and the other conditions were the same as in Example 1, divinylbenzene 220 g of crosslinked polyethyl methacrylate fibers were obtained.

This is called fibrous material B.

50 g of fibrous material B was placed in a flask 11 with 50 ml of 98% sulfuric acid, and treated at 100°C for 15 hours with stirring. After cooling, the contents were poured into a large amount of water, and the fibrous material was collected from door to door. The fibrous material was washed with deionized water until the pH of the P solution was 4.
It was washed until it reached 5 or higher.

This product contains 3.2 meq of NaOH per 1g of dry weight.
It had the ability to neutralize.

Example 4 50 g of fibrous material B was heated under reflux for 15 hours in a stainless steel flask with an alcoholic solution containing 200 g of potassium hydroxide, washed with water and then washed repeatedly with 2N hydrochloric acid 7 times, and further washed with deionized water to remove chloride ions. When washed until free, a cation-exchangeable fiber was obtained that had the ability to neutralize 9.8 meq of NaOH per 12 dry weight.

Example 5 A monomer mixture at 20°C consisting of 90 parts of methyl acrylate, 5 parts of divinylbenzene and 1.0 part of 2,2'-azobis(2,4-dimethylvaleronitrile) was heated to 3.1 parts.
252g was attached to a skein of denier triacetate filament yarn (weight 200g, circumference 180cm), 5
The fibers were immersed in a saturated solution of Glauber's salt kept at 8° C. for 2 hours, and polymerized while the monomer components were absorbed into the fibers.

After repeatedly passing this material between a pair of rollers with hard rubber surfaces to remove the adhesion between the fibers, the raw fibers were eluted using a Soxhlet extractor using dichloromethane as a solvent. A porous fibrous material made of polymethyl methacrylate was obtained.

This product was treated in the same manner as in Example 4, and alcoholic KOH
When refluxing the solution for 15 hours, 9.0 meq/g of N
A cation-exchangeable filament with aOH neutralization ability was obtained.

Example 6 70 parts of ethyl methacrylate, 30 parts of methyl acrylate
1 part of divinylbenzene, and 1 part of azobisisobutyronitrile were prepared, and the same procedure as in Example 1 was carried out except for using this mixture. 220 parts of filaments of ethyl methacrylate-methyl acrylate were obtained.

When this fibrous material is treated with pentaethylene hexamine in the same manner as in Example 1 to introduce ion exchange groups, the obtained ion-exchanged fibrous material has a hydrochloric acid neutralization ability of 6.4 meq per gram of dry weight. had.

Claims (1)

[Claims] 1 consists essentially of acrylic ester and/or methacrylic ester, divinylbenzene and a polymerization initiator,
A monomer mixture containing 0.3 to 40% divinylbenzene based on the total amount of monomers is applied to raw fibers that swell but do not dissolve at least at the polymerization temperature of the mixture, and the swelling ratio of the fibers is 30%. Polyacrylic acid ester and/or polymethacrylic acid crosslinked with divinylbenzene obtained by polymerizing the fibers while being absorbed into the fibers to a volume % or higher, and then decomposing or dissolving and removing the raw fiber constituents. A method for producing a porous ion-exchangeable fibrous material, which comprises introducing an ion-exchange group into an ester fibrous material.