JPH0985079A - Method for producing gelling agent that absorbs organic solvent and water - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To produce a gelling agent having a large solubility of an organic solvent having a solubility parameter value of 9 or more and water to form a gel and having an excellent ability to retain the absorbed organic solvent and water. Offer. A gelling agent that absorbs an organic solvent and water, wherein a cellulose derivative and a cross-linking agent that are soluble in an organic solvent or water having a solubility parameter value of 9 or more, and, if necessary, a reaction agent Dissolve or suspend in water to mix, then heat to gel and dry the resulting gel. The cellulose derivative has a hydroxypropyl group, and the viscosity of the aqueous solution of the derivative at a solid content concentration of 2% by weight is 100 when measured with a B-type viscometer at 25 ° C.
-1500 cps range.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a gelling agent that absorbs an organic solvent and water. More specifically, the present invention relates to a method for producing a gelling agent which absorbs a large amount of a wide range of polar organic solvents and water by itself swelling and, after absorbing, has excellent retention ability.

[0002]

2. Description of the Related Art Conventionally, as materials for absorbing organic solvents and water, hydrophilic fibers such as paper, pulp and cotton, hydrophobic fibers such as polyethylene fibers and polypropylene fibers, or hydrophilic fibers and hydrophobic fibers have been used. There are composite sheets and non-woven fabrics. However, all of these adsorb and retain organic solvents and water in the voids between the fibers due to the capillary phenomenon, and it is not possible to absorb a large amount, and it is easy to absorb what was once absorbed by applying external pressure. It has the drawback of being re-emitted.

As a solution to this drawback, there is known a synthetic resin-based oil absorbing agent of a type that absorbs an organic solvent into a certain polymer and swells. For example, JP-A-5-33
No. 7367 discloses an alkyl (meth) acrylate, an alkylaryl (meth) acrylate, an alkyl (meth) having a long-chain (3 to 30) aliphatic hydrocarbon group.
By polymerizing a monomer having at least one unsaturated compound selected from the group consisting of acrylamide, alkylaryl (meth) acrylamide, fatty acid vinyl ester, alkylstyrene and α-olefin as a main component and a crosslinkable monomer. Disclosed is an oil-absorbing agent comprising a mixture of the obtained oil-absorbent crosslinked polymer and a water-insoluble or sparingly water-soluble organic acid metal salt. This oil absorbing agent absorbs a large amount of oil and swells against a wide variety of oils even from an oil-water mixed system, has excellent oil retaining property of the absorbed oil, and has significantly improved oil absorbing speed.

On the other hand, as an alcohol gelling agent, for example, JP-A-2-286789 discloses an alcohol characterized by adding polyvinyl alcohol and benzylidene sorbitol or / and hydroxypropyl cellulose and water to an alcohol which is liquid at room temperature. Although a solid portable fuel of the type is disclosed, the alcohol is gelated by the interaction between the cellulose derivative which is not cross-linked in the alcohol and polyvinyl alcohol or benzylidene sorbitol. Is different from the gelation mechanism of.

[0005]

In view of the above situation, the inventors of the present invention have earnestly studied a material which absorbs water and an organic solvent having a solubility parameter value of 9 or more and gelates, and as a result, the solubility parameter value is obtained. Is added to a specific cellulose derivative soluble in 9 or more organic solvents and water, a crosslinking agent, and if necessary, a reaction auxiliary agent, and a solution or suspension of the resulting mixture is heated to perform a crosslinking reaction, and a gel It is found that a gel composed of a crosslinked cellulose derivative obtained by producing a gel and then drying the gel itself does not dissolve in the organic solvent and water, but conversely absorbs the solvent and water well to form a gel. The invention was completed. The object of the present invention is to absorb a large amount of an organic solvent having a solubility parameter value of 9 or more and water to form a gel by swelling without dissolving itself, and a gel excellent in the ability to retain the absorbed organic solvent and water. It is to provide a method for producing an agent.

[0006]

The first aspect of the present invention is to provide a cellulose derivative and a cross-linking agent which are soluble in an organic solvent or water having a solubility parameter value of 9 or more, and, if necessary, a reaction auxiliary agent in the solvent, water. Alternatively, it is a method for producing a gelling agent that absorbs an organic solvent and water, characterized by dissolving or suspending in a mixture of a solvent and water, mixing them, and then heating to form a gel, and drying the obtained gel. . A second aspect of the present invention is that the cellulose derivative has a hydroxypropyl group, and the viscosity of an aqueous solution of the derivative at a solid content concentration of 2% by weight is 25.
100-1500 cps when measured with B-type viscometer at ℃
The method for producing a gelling agent for absorbing an organic solvent and water according to the first aspect of the present invention is characterized in that

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The solubility parameter value used in the present invention is used as a scale representing the polarity of a compound and is defined as a value calculated by the following formula (1), and its unit is (Cal / c
m ³ ) ^1/2 (Polymer Handbook, Third Editi
on, JOHN WILEY & SONS, 1989). ^{_{δ i = {(H i v}} -RT) / V i} 1/2 ··· (1) However, [delta] _i = solubility of component i parameter values H _i ^v = heat of vaporization component i (cal) R = ideal Gas constant (cal / K · mol) T = absolute temperature (K) V _i = molar volume of component i (cm ³ / mol).

The cellulose derivative used in the present invention which is soluble in an organic solvent having a solubility parameter value of 9 or more or water has a hydroxypropyl group, and examples of such a derivative include hydroxypropyl cellulose, hydroxyethyl hydroxypropyl cellulose, Hydroxypropylmethyl cellulose and the like can be exemplified, and these can be used alone or appropriately selected and mixed. Further, the cellulose derivative is a substituent other than a hydroxypropyl group,
For example, it may contain one or more of methyl group, ethyl group, hydroxyethyl group, cyanoethyl group, carboxymethyl group, carboxyethyl group and the like. Further, the cellulose derivative may have any substitution degree (ratio of substituents bonded per anhydroglucose unit of cellulose) as long as it is soluble in an organic solvent having a solubility parameter value of 9 or more or water. You may use.

The cellulose derivative used in the present invention is
In addition to the above structural differences, when the cellulose derivative is dissolved in pure water at a solid concentration of 2% by weight, the viscosity of the aqueous solution becomes 1
It must be in the range of 00 to 1500 cps (25 ° C, B-type viscometer). When the viscosity of the aqueous solution is less than 100 cps, it means that the molecular weight of the cellulose derivative is too small, and the gelling agent obtained by using such a cellulose derivative has a significantly reduced absorption amount of the organic solvent and water, and is practically used. is not. On the contrary, when the viscosity of the aqueous solution exceeds 1500 cps, a uniform solution or suspension cannot be obtained due to insufficient fluidity when other chemicals are added and stirred, and the solution or suspension is homogenized. Therefore, if the concentration of the cellulose derivative is reduced, sufficient cross-linking becomes difficult to occur, and the gel strength is so weak that a desired gelling agent cannot be produced.

As described above, in the present invention, the cellulose derivative is uniformly dissolved or suspended in the solvent. At this time, if the solid content concentration is too low, it becomes difficult to form a gel or a large amount of a crosslinking agent is added. There is no choice but to do so, so it is good to set the concentration as high as possible. In the present invention, the solid content concentration when the cellulose derivative is dissolved or suspended is the type of the cellulose derivative, the viscosity when the solution is an aqueous solution,
Although it depends on the type of solvent and the like, it is in the range of 7 to 15% by weight based on the total weight. Examples of the solvent used include an organic solvent having a solubility parameter value of 9 or more, water, and when the organic solvent is soluble in water, a mixture of the organic solvent and water can be used, and the solvent is appropriately selected and used.

The cross-linking agent used in the present invention may be one which is reactive with the cellulose derivative in an organic solvent or water, for example, aldehydes such as formaldehyde and glyoxal; ethylene glycol diglycidyl ether, polyethylene glycol. Polyvalent epoxy compounds such as diglycidyl ether and diepoxy butane; Divinyl compounds such as divinyl sulfone and methylenebisacrylamide; Polyvalent halogen compounds such as dichloroacetone, dichloropropanol and dichloroacetic acid; Epichlorohydrin, epibromo Halohydrin compounds such as hydrin; and N, N'-hexamethylene-1-bis-
(1-aziridinecarboxamide), tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, and other polyvalent aziridine compounds, and the like. , Appropriately selected and used in one or more kinds.

When a mixture of a cellulose derivative and a cross-linking agent is heated for cross-linking, a reaction aid may be used depending on the type of the cross-linking agent. For example, when aldehydes are used as a cross-linking agent, an acid such as hydrochloric acid is required as a reaction aid, and divinyl compounds, polyvalent halogen compounds, polyvalent epoxy compounds and polyvalent aziridine compounds are required. When used, an alkali such as an alkali metal hydroxide is required as a reaction aid. The crosslinker addition rate is
The amount is 0.5% to 20% by weight based on the absolute dry weight of the cellulose derivative, although it depends on the type of the crosslinking agent. The addition rate is 0.
If it is less than 5% by weight, the amount of the gelling agent becomes too small and it becomes difficult to form a gel. On the contrary, if the amount of addition exceeds 20% by weight, the gelling agent obtained has a low absorption amount of organic solvent and water.

In the present invention, the cellulose derivative and the cross-linking agent are dissolved in a solvent, and if necessary, a reaction aid is added to dissolve or suspend the mixture, and the mixed solution or suspension thus obtained is added. The crosslinking reaction is carried out by heating at a temperature of 30 to 90 ° C. for 2 to 24 hours. If the temperature is lower than 30 ° C., the progress of the crosslinking reaction is slow, and if the temperature exceeds 90 ° C., the molecular weight of the cellulose derivative is promoted, and the gelling agent obtained has a reduced absorption amount with respect to the organic solvent and water. Regarding the time, usually, a block-like gel is formed in a heating time of 2 to 5 hours, but when the heating is continued within the range of 24 hours, the obtained gelling agent absorbs an organic solvent and water. Therefore, the longer the time is, the better. However, if the heating time exceeds 24 hours, the molecular weight of the cellulose derivative may be lowered, and the absorption amount may be lowered.

On the other hand, in carrying out the cross-linking reaction of the cellulose derivative, after applying or impregnating the solution or liquid-liquid suspension of the mixture before heating onto the synthetic film, sheet-shaped substrate, cloth or nonwoven fabric, It is also possible to obtain a product in which the gelling agent is supported on the base material used by simultaneously performing the crosslinking reaction and drying by heating under the conditions of temperature and time. By this method, a gelling agent in the form of a film, a sheet, a cloth or a non-woven fabric can be obtained and applied to various uses. Furthermore, short fibers such as pulp fibers are mixed with an aqueous solution or suspension of the above-mentioned cellulose derivative mixture before crosslinking, and the mixture is heated and dried to impart strength to the gelling agent, or similarly aluminum hydroxide is used. It is also possible to impart flame retardancy to the gelling agent by mixing a flame retardant or non-flammable substance such as aluminum oxide. The cross-linked cellulose derivative gelling agent thus obtained contains unreacted cross-linking agent and reaction aid, but may be dried as it is or may be removed by post-treatment. In that case, for example, the water-soluble impurities can be removed by repeating the operation of swelling the obtained gelling agent in water, then taking it out, and heating and de-swelling it several times.

As described above, the gelling agent of the present invention can be obtained by removing the impurities contained in the gel produced by the reaction, or by removing the impurities and then removing the organic solvent and water. When the organic solvent in the gel contains water, a gelling agent having a higher absorption capacity can be obtained by substituting water in the gel with an organic solvent and then drying. As a method for replacing water in the gel with an organic solvent, there are a method using an organic solvent miscible with water and a method using an organic solvent immiscible with water. For the former, lower alcohols such as methanol and ketones such as acetone are used, and the gel containing water is immersed in the water-miscible organic solvent for a certain period of time to make the water in the gel miscible with water. Substitution with an organic solvent. For the latter, an organic solvent which is immiscible with water, such as toluene, and which is azeotropic with water at a temperature of 100 ° C. or higher is used, and the gel containing water is heated in an organic solvent which is immiscible with water. The water in the gel is removed azeotropically. The gel is preferably dried at a temperature of 150 ° C. or lower after the removal of water by an organic solvent and the dehydration of the gel, hot air drying, microwave drying,
The organic solvent in the gel can be removed by using a known drying method such as infrared drying or reduced pressure drying.

On the other hand, the block-shaped gel can improve the absorption rate of the solvent by reducing the particle size. As a method for reducing the particle size, a gel-like gel immediately after the crosslinking reaction may be pulverized with a cutter, a mixer, or the like, and a gelling agent after dehydration drying may be pulverized with a mill. The gelling agent of the present invention thus obtained has a film shape, a sheet shape, a cloth shape, a non-woven cloth shape, or a block shape, a granular shape, or a powder shape, and has an solubility parameter value of 9 or more, an organic solvent, or water. Alternatively, the mixture of both is absorbed and gelled, and the absorbed solvent can be retained even under pressure, and the gelling agent is biodegradable because the raw material is cellulose.

The gelling agent of the present invention can be used in various forms, for example, a block, granular or powdery gelling agent may be directly dispersed in the liquid, such as a cylindrical tube. The liquid to be absorbed may be allowed to pass through by filling the inside of an open system container. Alternatively, as another method, the block shape,
Granular or powdery gelling agent may be used by filling it in a bag or a porous package having good liquid permeability, and further, pulp fiber, cotton, nonwoven fabric, porous calcium carbonate, porous silica, nylon fiber, It can be used in combination with a known filler or absorbent such as polypropylene fiber. on the other hand,
The film-like or sheet-like gelling agent of the present invention can also be used as a recording material that absorbs hydrophilic ink.
As described above, the gelling agent obtained by the present invention is a leakage organic solvent treating agent, an organic waste liquid solidifying agent, an organic solvent gas adsorbent, an industrial or household wiping material, a chemical wipe, a solvent leakage sensor, an organic solvent. Solvent retention material, soil water retention material,
Widely used as a field for agricultural materials such as nursery sheets, food freshness-maintaining materials, food fields for fungicides, dehydrating agents, building materials such as dew condensation prevention sheets for buildings, various release agents for aromatic agents, insecticides, etc. It can be used for.

[0018]

The present invention will be described in more detail with reference to the following examples, but of course the present invention is not limited thereto. Unless otherwise specified,% means% by weight.

Example 1 2 g of sodium hydroxide was dissolved in 76 g of water, and then 970 g of isopropyl alcohol and 10 g of ethylene glycol diglycidyl ether were mixed, and hydroxypropyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd., 2% aqueous solution type B) was mixed with stirring. 100 g of a viscosity measured by a viscometer was 250 cps) and dissolved to prepare a mixed solution in which the concentration of hydroxypropyl cellulose based on the total weight was 8.6%. next,
This mixed solution was heated at a temperature of 40 ° C. for 16 hours to cause a crosslinking reaction to form a gel. The obtained gel was cut into a 5 mm square with a cutter knife and immersed in 400 g of 1N hydrochloric acid for 1 hour to remove excess sodium hydroxide. The obtained hydrated gel was transferred to 6000 g of water, heated to 50 ° C. to drive out water in the gel and then taken out, followed by 5
It was immersed in 000 g of acetone for 2 hours to completely replace water with acetone, taken out, and dried under reduced pressure to obtain a gelling agent. The quality of the dried gelling agent thus obtained was evaluated by measuring the amounts of various organic solvents and pure water absorbed by the following measuring methods.

Method of measuring absorption amount 0.8 g of a dried sample was sealed in a 10 cm × 10 cm 250-mesh nylon net bag, which was shown in Table 1 and Table 2 below.
Solubility parameter value shown in is immersed in various measured solutions consisting of an organic solvent and water in the range of 7 to 24 for 24 hours for absorption, and then pulled up and suspended for 10 minutes to drain, Weigh the sample and dry sample 1
The measured solution (g) absorbed per g was defined as the absorption amount before pressurization. Then, the No. 2 Sheets of filter paper (made by Toyo Roshi Kaisha, Ltd.) 25 sheets (10 sheets above the gelling agent, 15 sheets below the gelling agent as well) were sandwiched, and a stainless steel plate having a diameter of 16 cm and a weight of 100 g was stacked on the stacked filter sheets. Then, a weight of 1 kg was placed on the sample, and pressure was applied to the sample for 5 minutes so that the liquid existing in the gap in the gel was absorbed by the filter paper. After that, the weight of the sample was measured, and the measured and absorbed solution (g) per 1 g of the absolutely dried sample was defined as the absorption amount after pressurization.

The solution to be measured used for the measurement is shown below. However, the number in parentheses indicates the solubility parameter value of the solution to be measured. (1) Solvent having a solubility parameter value of 9 or more: Pure water obtained by distilling deionized water through an ion exchange resin (2
3.4), ethylene glycol (14.6), methanol (14.5), ethanol (12.7), isopropyl alcohol (11.5), acetic acid (10.1), acetone (9.9), chloroform. (9.3), tetrahydrofuran (9.1). (2) Solvent having a solubility parameter value of less than 9: toluene (8.9), cyclohexane (8.2), n-hexane (7.3).

Example 2 In the same manner as in Example 1 except that the obtained hydrated gel was heated in 4000 g of toluene and azeotropically dehydrated instead of immersing the obtained hydrated gel in acetone to remove water. It was dried under reduced pressure to obtain a gelling agent. The amount of absorption of the solution to be measured was measured in the same manner as in Example 1.

Example 3 10 g of sodium hydroxide was dissolved in 76 g of water, then 5 g of epichlorohydrin and 970 g of isopropyl alcohol.
And then 100 g of hydroxypropyl cellulose
Were mixed to form a mixed solution having a hydroxypropylcellulose concentration of 8.6% based on the total weight, and the mixed solution was heated at a temperature of 40 ° C. for 16 hours. The obtained hydrated gel was heated in 4000 g of toluene to undergo azeotropic dehydration, and then Example 1
It was dried under reduced pressure in the same manner as above to obtain a gelling agent. The amount of absorption of the liquid to be measured was measured in the same manner as in Example 1.

Example 4 10 g of sodium hydroxide, 5 g of N, N'-methylenebisacrylamide and 9 of isopropyl alcohol were added to 76 g of water.
Add 70 g, then hydroxypropyl cellulose 1
00 g was mixed to form a mixed solution having a hydroxypropylcellulose concentration of 8.6% based on the total weight, and the mixed solution was heated at a temperature of 40 ° C. for 16 hours. The obtained hydrated gel was heated in 4000 g of toluene for azeotropic dehydration, and then dried under reduced pressure in the same manner as in Example 1 to obtain a gelling agent. The amount of absorption of the liquid to be measured was measured in the same manner as in Example 1.

Example 5 In 900 g of tetrahydrofuran, 100 g of hydroxyethyl hydroxypropyl cellulose (manufactured by itself, the viscosity of a 2% aqueous solution by a B type viscometer is 450 cps) and 2 g of toluene diisocyanate were dissolved, and the concentration of hydroxyethyl hydroxypropyl cellulose was adjusted to the total weight. A 10.0% mixed solution was prepared, and this mixed solution was heated at a temperature of 40 ° C. for 10 hours. The resulting gel is cut into 5 mm squares and 5000 g
It was put into a mixer with water and crushed. Put the crushed gel in a 10 liter container for 1 hour, then raise the temperature to 50 ° C. to drive out the water in the gel, heat the obtained hydrated gel in 4000 g of toluene, and azeotropically dehydrate it. It was dried under reduced pressure in the same manner as in Example 1 to obtain a gelling agent. The amount of absorption of the liquid to be measured was measured in the same manner as in Example 1.

Example 6 To 100 g of hydroxypropyl cellulose, 5 g of a zinc borofluoride aqueous solution having a solid concentration of 45% and 700 g of water were added to form a uniform mixed solution, and then 10 g of ethylene glycol diglycidyl ether was further mixed, based on the total weight. Was prepared as a mixed solution having a hydroxypropylcellulose concentration of 12.3%, and the mixed solution was heated at a temperature of 40 ° C. for 8 hours to form a gel. The obtained gel was put into a mixer together with 6000 g of methanol and crushed, and the crushed gel was filtered,
Then, the gel was dipped in 5000 g of water for 1 hour, the resulting hydrated gel was heated in 4000 g of toluene for azeotropic dehydration, and then dried under reduced pressure in the same manner as in Example 1 to obtain a gelling agent. The amount of absorption of the liquid to be measured was measured in the same manner as in Example 1.

Example 7 10 g of sodium hydroxide was dissolved in 76 g of water, then 5 g of epichlorohydrin and 970 g of isopropyl alcohol.
Was further added, and 100 g of hydroxyethylhydroxypropylcellulose used in Example 5 was mixed to form a mixed solution having a concentration of hydroxyethylhydroxypropylcellulose of 8.6% based on the total weight.
A gel was obtained by heating at 0 ° C. for 16 hours, and the gel was cut into 1 cm squares. The cut gel was put into a mixer together with 5000 g of an aqueous sodium sulfate solution having a solid content of 6% and ground. The unused alkali in the crushed gel was neutralized with the minimum amount of concentrated sulfuric acid, left for 1 hour, and then filtered to obtain 100 parts of warm water.
After washing 3 times with 0 g, the gel obtained was washed with toluene 400
A gelling agent was obtained in the same manner as in Example 1 after heating in 0 g for azeotropic dehydration. The amount of absorption of the liquid to be measured was measured in the same manner as in Example 1.

Comparative Example 1 An aqueous solution having a solid content of 2% has a viscosity of 8c as measured by a B-type viscometer.
A dried gelling agent was obtained in the same manner as in Example 3 except that ps hydroxypropyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd.) was used. The amount of absorption of the liquid to be measured was measured in the same manner as in Example 1.

Comparative Example 2 10 g of sodium hydroxide was dissolved in 240 g of water, and 5 g of epichlorohydrin and 17 of isopropyl alcohol were dissolved in this solution.
3. 10 g was added and mixed, and then 100 g of hydroxypropyl cellulose (manufactured by Tokyo Kasei Kogyo Co., Ltd.) having a viscosity of 1700 cps according to a B-type viscometer of an aqueous solution having a solid content of 2% was mixed, and the concentration of hydroxypropyl cellulose was 4. An 8% mixed solution was prepared, and this mixed solution was heated at a temperature of 40 ° C. for 16 hours to form a gel. However, the gel obtained had a weak gel strength and could not be further processed.

The results obtained in Examples and Comparative Examples are shown in Tables 1 and 2.

[0031]

[Table 1]

[0032]

[Table 2]

As is clear from Tables 1 and 2, the gelling agent obtained by the present invention has a solubility parameter value of 9
It has extremely excellent swelling and absorption ability with respect to the above organic solvents and water, does not easily release the absorbed liquid even when pressurized, and has excellent holding power (Examples 1 to 7). On the other hand, the viscosity of the solution having a solid content of 2% by the B-type viscometer is 100 cps.
The gelling agent (Comparative Example 1) obtained from a lower cellulose derivative is inferior in swelling and absorption ability to water and an organic solvent having a solubility parameter value of 9 or more, and is not suitable for practical use as a gelling agent. Also, the viscosity of a 2% solids concentration solution is 1
When a cellulose derivative higher than 500 cps is used (Comparative Example 2), a low concentration (less than 5%) is unavoidable in order to obtain a uniform solution, and then the crosslinking reaction proceeds even if this is reacted with a crosslinking agent. First, a gel having a weak gel strength was obtained, and a gelling agent could not be finally obtained.

[0034]

INDUSTRIAL APPLICABILITY The present invention has the ability to swell and absorb into a wide range of organic solvents having a solubility parameter value of 9 or more and water to form a gel, and does not easily release the absorbing liquid even when pressurized,
Moreover, since the raw material is a cellulosic material, it is effective to provide a method for producing a gelling agent having biodegradability.

Claims (2)

[Claims] 1. A cellulose derivative and a crosslinking agent which are soluble in an organic solvent or water having a solubility parameter value of 9 or more, and a reaction aid, if necessary, are dissolved or suspended in the solvent, water or a mixture of the solvent and water. A method for producing a gelling agent for absorbing an organic solvent and water, which comprises: mixing and mixing, and then heating to form a gel, and drying the obtained gel. 2. The cellulose derivative has a hydroxypropyl group, and the viscosity of an aqueous solution of the derivative at a solid content concentration of 2% by weight is in the range of 100 to 1500 cps when measured by a B-type viscometer at 25 ° C. The method for producing a gelling agent according to claim 1, wherein the gelling agent absorbs the organic solvent and water.