JP5717422B2 - Method for producing gel composition - Google Patents

Description

  The present invention relates to a gel composition, and particularly to a method for producing a gel composition using an aqueous solvent.

  In general, a gel or a gel-like composition is a kind of dispersion system in physicochemical terms, and means a semi-solid material system that has lost fluidity with high viscosity due to a network of dispersoids. Includes a solid sol that is a colloid of a dispersion medium.

  In addition, when the gel is classified according to the material system, the gel whose dispersoid is a polymer and has a network structure by crosslinking or the like is called a polymer gel, the dispersion medium is a water gel, the dispersion medium is an organic solvent, The case of a gel is usually called an organogel.

  Among the above, polymer gels that use aqueous solvents as dispersion media are hydrogels, so they can be used in a wide range of applications, including ink compositions for writing instruments and half-cell electrode materials for various electrochemical measurements. Is expected.

  Conventionally, a technique is known in which an aqueous solution is partially gelled with a cross-linked acrylic polymer or the like to precipitate a gel-like substance. For example, JP 2001-181354 A (Patent Document 1) discloses a polymerizable cationic monomer containing a specific quaternary cation group and a polyoxyethylene chain-containing polymerizable monomer in the field of cleaning compositions. It is known that a gel-like substance is precipitated by diluting a composition obtained by copolymerizing with water.

  Further, JP-A-2001-139828 (Patent Document 2), JP-A-2002-500247 (Patent Document 3) and JP-A-2002-138147 (Patent Document 4) disclose absorbent materials such as disposable diapers. A water-swellable crosslinked polymer composition or a water-absorbing polymer is disclosed.

  On the other hand, JP-A No. 2001-255298 (Patent Document 5) and Japanese Patent No. 4413514 (Patent Document 6) disclose specific hydrogels used for electrode materials for electrochemical measurement.

  However, in the conventional production technology of so-called hydrogel polymer gels, it is difficult to make a gelation reaction system containing an aqueous solvent homogeneously and directly, especially phase separation between liquid phase and gel phase or liquid phase There is a problem that the gel becomes a heterogeneous gel caused by leaching of the electrolyte, and such a tendency is remarkable particularly when the aqueous electrolyte solution is gelled.

JP 2001-181354 A JP 2001-139828 A JP 2002-500247 A JP 2002-138147 A JP 2001-255298 A Japanese Patent No. 4413514

  The present invention has been made in view of the above-described situation in the prior art, and has problems such as phase separation by homogenously and directly gelling a gelling reaction system containing an aqueous solvent by a relatively simple process. It aims at providing the method for obtaining the gel-like composition which does not arise.

  In order to achieve the above object, a method for producing a gel-like composition according to the present invention includes a water-soluble polymer composed of a polyethyleneimine polymer by a crosslinking reaction in an aqueous solvent under uniform gelation conditions. The reaction system containing the aqueous solvent is directly gelled into a gel material substantially composed of a homogeneous phase.

  In a preferred embodiment of the present invention, the aqueous solvent comprises ion-exchanged water or a relatively high concentration aqueous electrolyte solution, more preferably the aqueous electrolyte solution comprises an aqueous solution of an alkali metal salt or an alkaline earth metal salt, particularly preferably. The electrolyte aqueous solution is composed of a saturated potassium chloride aqueous solution.

  In a preferred embodiment of the present invention, the water-soluble polymer is composed of polyethyleneimine having a number average molecular weight of 300 to 100,000, and more preferably includes a step of crosslinking polyethyleneimine with a glycidyl ether crosslinking agent.

  Furthermore, a preferred embodiment of the present invention includes a step of crosslinking polyethyleneimine with a crosslinking agent comprising a water-soluble polyglycidyl ether, preferably polyglycol diglycidyl ether.

  Furthermore, this invention includes the gel-like composition obtained by said method.

  According to the method of the present invention, it is possible to obtain a gel-like composition that does not cause problems such as phase separation by homogenizing and directly gelling a gelation reaction system containing an aqueous solvent by a relatively simple process, It is extremely useful in industry.

  Hereinafter, preferred embodiments of the method for producing a gel composition according to the present invention will be described.

  In the method for producing a gel composition according to the present invention, a water-soluble polymer composed of a polyethyleneimine-based polymer is subjected to a crosslinking reaction in a water-based solvent under uniform gelation conditions. It is characterized in that it is directly gelled into a gel-like substance consisting essentially of a homogeneous phase.

  As an aqueous solvent constituting the hydrogel, water, preferably ion-exchanged water, or an aqueous electrolyte solution can be used. In a preferred embodiment of the present invention, the aqueous solvent comprises ion-exchanged water or a relatively high concentration aqueous electrolyte solution, and more preferably the aqueous electrolyte solution comprises an aqueous solution of an alkali metal salt or an alkaline earth metal salt. Examples of aqueous solutions of such alkali metal salts or alkaline earth metal salts include lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, lithium bromide, sodium bromide, potassium bromide, magnesium bromide, bromide. Calcium, lithium nitrate, sodium nitrate, potassium nitrate, lithium perchlorate, sodium perchlorate, potassium perchlorate, lithium acetate, sodium acetate, potassium acetate, lithium sulfate, sodium sulfate, potassium sulfate and the like can be preferably used.

  The concentration of the aqueous electrolyte solution can be appropriately selected according to the intended application, but the present invention is characterized in that it can be homogeneously gelled even with a high concentration aqueous electrolyte solution, preferably 3 mol / l to Even in the range of saturated aqueous solution, it has the characteristic which is not in the past also in the point which can obtain a homogeneous gel composition.

  In particular, in a gel composition using a conventional electrolyte aqueous solution as a solvent, it was difficult to obtain a composition having good homogeneity without phase separation. Even in the case where is used as a solvent system, it is useful in that a homogeneous gel composition can be obtained.

  The water-soluble polymer used in the present invention is preferably a polyethyleneimine having a number average molecular weight in the range of 300 to 100,000, more preferably in the range of 600 to 80000, particularly preferably in the range of 1800 to 70000. It is desirable to use it.

  In the present invention, it is preferable to crosslink the water-soluble polymer together with the above-described aqueous solvent with a crosslinking agent. Examples of such cross-linking agents include ethylene polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, propylene polypropylene glycol diglycidyl ether. Glycidyl ether-based crosslinking agents such as these are preferred, and one or more of these crosslinking agents can be used.

  In the present invention, the mixing ratio of the water-soluble polymer can be appropriately selected in accordance with the water-soluble polymer to be used, but is usually preferably 0.1 to 50% by mass with respect to the aqueous solvent. More preferably, it is the range of 1-30 mass%.

  Furthermore, in the present invention, the above-mentioned crosslinking agent can be appropriately selected in the optimum range depending on the water-soluble polymer to be used, but usually 0.1 parts by mass to 10 parts by mass with respect to 1 part by mass of the water-soluble polymer. Part is preferable, and the range of 0.3 to 8 parts by mass is more preferable.

  In the method for producing a gel composition according to the present invention, the above-mentioned polyethyleneimine polymer is dissolved in an aqueous solvent, and a crosslinking agent is further added. For example, the crosslinking reaction is carried out in a mild heating temperature range of 20 to 80 ° C. In addition, by causing a denaturation reaction, the entire reaction system is directly gelled in a homogeneous state.

  The gel-like composition thus obtained is gelled in a direct and homogeneous state of the entire reaction system, and substantially no liquid phase or solid phase precipitation or phase separation is observed. Moreover, according to the method of the present invention, the gel composition obtained has a relatively high light transmittance, and a gel composition in a transparent to white range can be obtained in a relatively simple process with little heat load. Can do.

  The reason why such a homogeneous gel composition is obtained by the present invention is not necessarily clear, and the present invention is not limited to any theory, but is presumed as follows.

  It is considered that the gelation ability of a crosslinked polymer composed of a water-soluble polymer and a crosslinking agent in an aqueous solvent is caused by the affinity and the degree of freedom of the crosslinked polymer molecule in the solvent. If the affinity and the degree of freedom between the solvent and the crosslinked polymer are too high, the crosslinked polymer does not form a gel and is in a dissolved state in the solvent, causing no change in physical properties or a change in the degree of thickening. In addition, if the degree of freedom of the crosslinked polymer and the affinity with the solvent are too low, the polymer cannot form a mutual state with the solvent, resulting in a phase separation such as precipitation or a concentrated phase or a degree of gelation. It is thought that it will stay. Therefore, in order to gel the solvent uniformly, it is necessary for the crosslinked polymer to have an appropriate force of molecules for gelling while maintaining affinity with the solvent. In order to give the crosslinked polymer an appropriate affinity for the solvent, a hydrophilic portion exhibiting affinity with the solvent and a crosslinked portion serving as a force force group are appropriately introduced into the crosslinked polymer. The hydrophilic part is an amino group, an imino group, a tertiary amino group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, an ethylene oxide group, a propylene oxide group, etc., and the crosslinking part is the molecular chain size of the crosslinking agent And the number of functional groups can be considered as factors. Since polyethyleneimine contains many amino groups and imino groups that are hydrophilic and highly reactive in the molecule, it is suitable for these designs and can be suitably used. What is necessary is just to design suitably the functional group to introduce | transduce, a ratio, a crosslinking degree, etc. according to the aqueous solvent to be used. In particular, since a relatively high concentration aqueous electrolyte solution contains a large amount of inorganic salt as a solute, it is necessary to consider a high salting out effect. When the cross-linking reaction proceeds using a water-soluble polymer and a cross-linking agent appropriately designed in this manner, the cross-linking and modification proceed while containing the solvent in its own macromolecules. As it forms, the crosslinked polymer is believed to form a substantially homogeneous gel.

  Accordingly, the uniform gelation condition for obtaining a homogeneous gel composition in the present invention means that the water-soluble polymer causes a crosslinking reaction in a state of being uniformly dissolved in the aqueous solvent, but more specifically. Specifically, in the present invention, the uniform gelation condition refers to a homogeneous gel in which phase separation does not occur by maintaining an appropriate affinity between the solvent and the crosslinked polymer and controlling the affinity to an optimum state. It means the condition to realize

  The present invention can be applied to an ink composition for a writing instrument comprising the gel composition.

  Specifically, for example, the writing ink composition of the present invention described above can have a minimum configuration including at least the gel composition and the colorant.

  The mixing ratio of the crosslinked polymer composed of the water-soluble polymer and the crosslinking agent in the writing ink composition of the present invention is preferably 0.1% by mass to 20% by mass with respect to the total amount of the writing ink composition. .

  As the colorant used in the writing ink composition of the present invention, dyes, pigments and the like can be used. Examples of the dye include acid dyes, basic dyes, and direct dyes. Specifically, acid dyes include Acid Orange 56, Acid Yellow 3, Acid Yellow 23, Acid Red 18, Acid Red 51, Acid Red 52, Acid Red 73, Acid Red 87, Acid Red 92, Acid Red 94, Acid Blue 9, Acid Blue 62, Acid Blue 90, Acid Blue 103, Acid Black 2 and the like are listed. Examples of basic dyes include rhodamine, methyl violet and Victoria Blue FB. Direct dyes include Direct Black. 19, Direct Black 154, Direct Yellow 44, Direct Blue 3, Direct Blue 71, Direct Blue 86, Direct Orange 6, and the like.

  The said dye can be mix | blended 1 type or in mixture of 2 or more types suitably, As the compounding ratio, it is preferable that it is 1-40 mass% with respect to the ink composition for writing.

  Examples of the pigment include organic pigments and inorganic pigments. Specifically, examples of the organic pigment include copper phthalocyanine blue, benzidine yellow, and azo pigments. Examples of the inorganic pigment include white pigments such as carbon black, ultramarine, and titanium dioxide, metal powder pigments such as aluminum, Examples include natural mica, alumina, glass pieces, pearl pigments, fluorescent pigments and phosphorescent pigments.

  Moreover, the water-dispersed pigment product etc. which were previously disperse | distributed in the aqueous medium can also be used. Specifically, Sandy Super series manufactured by Sanyo Dye Co., Ltd., Fuji SP Color Series manufactured by Fuji Dye Co., Ltd., Titicaca Color Series manufactured by Mikuni Dye Co., Ltd., and Dainichi Seika Kogyo Co., Ltd. TC Color series made by the company etc. are mentioned.

  Also, polar carbon, acidic carbon, graft carbon, and easily dispersible processed pigment obtained by surface processing of pigment with a dispersible resin can be used.

  Furthermore, fine fluorescent pigments in which various fluorescent dyes are formed into a solid solution in a resin matrix can be used as the fluorescent pigment. Specific examples include Lumicol NKW series manufactured by Nippon Fluorescent Co., Ltd., SW series, SP series, SF series manufactured by Sinloihi Co., Ltd., Victoria Color Series manufactured by Mikuni Dye Co., Ltd., and the like.

  The pigments can be used alone or in combination of two or more, and the mixing ratio is preferably 1 to 40% by mass with respect to the total amount of the writing ink composition.

  As the colorant used in the present invention, the dye and the pigment may be used in combination.

  The writing ink composition of the present invention can use various water-soluble organic solvents as necessary. As the water-soluble organic solvent, conventional general-purpose solvents that are compatible with water and aqueous electrolyte solutions are used. Specifically, alcohols such as ethanol, propanol, and butanol, glycerin, sorbitol, ethylene glycol, diethylene glycol, thiol Polyethylene alcohols such as diethylene glycol, hexylene glycol, 1,3-butanediol, neoprene glycol, polyethylene glycol, propylene glycol, butylene glycol, thioglycols such as thiodiethylene glycol, triethanolamine, diethanolamine, monoethanolamine, etc. Alkanolamines, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene Glycol monoethyl ether, ethylene glycol monomethyl ether acetate, alkylene glycol alkyl ethers and their derivatives, such as propylene glycol monomethyl ether, 2-pyrrolidone, etc. pyrrolidones and their derivatives such as N- methyl-2-pyrrolidone.

  The said water-soluble organic solvent can use together 1 type, or 2 or more types, As a compounding ratio, it is preferable that it is 2-60 mass% with respect to the ink composition for writing.

  In addition, various additives such as pH adjusters, antiseptics, antifungal agents, wetting agents, rust preventives, lubricants, and surfactants can be blended as necessary.

  As a method for producing the writing ink composition of the present invention, after obtaining the gel composition of the present invention in advance, a colorant, and if necessary, a water-soluble organic solvent and other various additives are blended and mixed and stirred. The method of obtaining the ink composition for writing by dissolving the polyethyleneimine and the crosslinking agent in an aqueous solvent, blending the colorant, water-soluble organic solvent and various additives as necessary, in a homogeneous state Examples thereof include a method of obtaining a writing ink composition simultaneously with direct gelation.

  Furthermore, the present invention can be suitably applied to an electrode or a cleaning composition comprising the gel composition.

  Hereinafter, an actual manufacturing example will be specifically described including its manufacturing method and results. (In the following examples, Examples 3-7, 17-22, 24-26, 28-32 are examples of the present invention, and Examples 1, 2, 8-16, 23, 27 are comparative examples.)

Production Example 1
In a mixing ratio shown in Table 1 below, 10 parts by mass of a 30% by mass polyethyleneimine aqueous solution (manufactured by Nippon Shokubai Co., Ltd., trade name Epomin P-1000, number average molecular weight 70000) is added to an aqueous solvent (3.3M-potassium chloride electrolyte aqueous solution). Or it was dissolved in ion-exchanged water). Next, a cross-linking agent shown in Table 1 below was added thereto and dissolved uniformly to prepare a reaction composition.

The obtained reaction composition was filled in a glass tube, heat-treated at 60 ° C. for 20 hours, and further subjected to a crosslinking reaction to cause a gelation reaction. Table 1 shows the results of gelation evaluation including the presence or absence of the formation of a gel substance.

Production Example 2
3 parts by mass of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd.) was dissolved in an aqueous solvent (3.3M-potassium chloride electrolyte aqueous solution) at a blending ratio shown in Table 2 below. Next, a cross-linking agent shown in Table 5 below was added thereto and dissolved uniformly to prepare a reaction composition.

The obtained reaction composition was filled in a glass tube, heat-treated at 60 ° C. for 20 hours, and further subjected to a crosslinking reaction to cause a gelation reaction. Table 2 shows the results of gelation evaluation including the presence or absence of the formation of a gel substance.

<Evaluation method of gelation>
The state of gelation was visually observed and evaluated according to the following criteria.
(Double-circle): It is a colorless and transparent-white transparent homogeneous gel, and phase separation is not seen.
Δ: Some gelation is observed, but part of the aqueous solution is phase-separated, and a homogeneous gel is not obtained.
X: Gelation did not occur.

  In addition, according to said result, when the length of the ethylene oxide of diglycidyl ether is n = 2 or less, a partial contraction is seen in a production | generation gel.

Claims (2)

A gel-like composition comprising a homogeneous phase comprising an aqueous solvent, polyethyleneimine, and polyethylene glycol diglycidyl ether, wherein the polyethylene glycol diglycyl ether is represented by the following general formula object.

(Where n is 4 to 22) An ink composition for a writing instrument, comprising the gel composition according to claim 1 .