JP2009062478A - Continuous production method of organic-inorganic composite hydrogel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous production method of organic-inorganic composite hydrogel, by which a water-swellable clay mineral can uniformly be dispersed and a mixed solution can continuously be transferred even after a catalyst and a polymerization initiator are added and mixed. <P>SOLUTION: The continuous production method comprises: a step of continuously dispersing an water-soluble organic monomer having a polymerizable vinyl group and a water-swellable clay mineral into water by using a vibrating agitator (i) and then continuously dispersing a polymerization initiator by a vibrating agitator (ii); and a step of polymerizing the water-soluble organic monomer. The vibrating agitators (i), (ii) each have a cylindrical casing whose upper and lower surfaces are closed, a flow passage inside the casing, through which a reaction solution flows, an introducing port for introducing the reaction solution, which is provided at one of the upper and lower surfaces, and a flow-out port provided at the other surface. Further, the vibrating agitators (i), (ii) each have an agitation body reciprocatively movable in the flow direction of the reaction solution. The continuous production method of the organic-inorganic composite hydrogel has a mechanism for agitating the reaction solution by the agitation body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a continuous production method of an organic-inorganic composite hydrogel having a three-dimensional network structure formed from a polymer of (meth) acrylamide monomers and a water-swellable clay mineral.

  Acrylamide-based hydrogels and acrylate-based hydrogels exhibit excellent water swellability, and are useful materials for medical materials, water-absorbing and drainage materials, soil improvement materials and the like by taking advantage of their characteristics. In particular, as nanocomposite materials exhibiting excellent mechanical properties, organic-inorganic composite hydrogels in which clay minerals are uniformly dispersed in organic polymers have been disclosed by the inventors of the present invention (for example, Patent Documents 1 and 2). According to this report, a water-swellable clay mineral is dispersed in an aqueous medium, and then a monomer of an acrylamide or methacrylamide derivative is added to polymerize the monomer in the presence of a polymerization initiator and a catalyst. It is described that an organic-inorganic composite hydrogel having good mechanical properties can be produced.

  In the production of the organic-inorganic composite hydrogel, uniform dispersion of the water-swellable clay mineral at the nanoscale and uniform mixing of the catalyst and the polymerization initiator are performed in order to exhibit the mechanical properties, water-swelling performance, and transparency of the organic-inorganic composite hydrogel. Processing is important. In the conventional method for producing the organic-inorganic composite hydrogel, the water-swellable clay mineral is uniformly dispersed and the polymerization initiator and the catalyst are added and mixed by stirring in a vial container or tank. In the case of the dispersion treatment of the water-swellable clay mineral by stirring in the tank, it is necessary to add the water-swellable clay mineral very slowly in order to achieve the dispersion of the water-swellable clay mineral that tends to aggregate. For this reason, a large amount of process time is required to complete dispersion on a large scale, or uniform dispersion may not be achieved. In addition, when adding or mixing a polymerization initiator, a rapid increase in viscosity occurs due to gelation within a few minutes after the addition, making it difficult to transfer a large amount of the reaction preparation solution after addition of the initiator. I couldn't get anything.

JP2002-53762 JP-A-2004-143212

  Therefore, the object of the present invention is that it takes a lot of process time to complete the dispersion, it is difficult to uniformly disperse the water-swellable clay mineral at the nanoscale, and further gelation occurs within a few minutes after the addition of the polymerization initiator. The problem of mass production of organic-inorganic composite hydrogels such that the reaction solution cannot be transferred after the addition of a polymerization initiator is possible due to the sudden increase in viscosity caused by the solution, and the water-swellable clay mineral can be uniformly dispersed. By providing a continuous production method of an organic-inorganic composite hydrogel that can be continuously transferred even after a catalyst and a polymerization initiator are added and mixed, and can be stably produced even on a large scale. is there.

  As a result of diligent research in view of the problems in the method for producing the organic-inorganic composite hydrogel, the inventor of the present invention dispersed a water-swelling clay mineral uniformly and added and mixed the catalyst and the polymerization initiator. It has been found that mass production by continuous treatment of an organic-inorganic composite hydrogel can be achieved by using both steps.

  That is, the present invention is a process for producing a reaction liquid by continuously dispersing a water-soluble organic monomer having a polymerizable vinyl group and a water-swellable clay mineral in water using a vibration stirrer (i), a polymerization initiator, Of the organic-inorganic composite hydrogel in which the step of continuously dispersing the water-soluble organic monomer in the reaction liquid in which the polymerization initiator is dispersed is sequentially dispersed in the reaction liquid using a vibration stirrer (ii) And the vibration stirrer (i) and the vibration stirrer (ii) include a cylindrical casing with the upper and lower end surfaces closed, a flow passage through which the reaction liquid flows, and one of the upper and lower end surfaces. The reaction solution introduction port provided on the other end face, and an outlet provided on the other end face, and further disposed in the flow passage, and capable of reciprocating in the flow direction of the reaction solution, And agitation attached around the shaft Provided is a method for producing an organic-inorganic composite hydrogel comprising a stirrer composed of roots and having a mechanism for stirring the reaction liquid by a stirrer that reciprocates in the flow direction of the reaction liquid. It is.

  Through continuous processing using a vibration stirrer, process time on a mass production scale can be shortened, automated, and the like, and productivity can be improved.

The present invention
(1) a step of producing a reaction solution by continuously dispersing a water-soluble organic monomer having a polymerizable vinyl group and a water-swellable clay mineral in water using a vibration stirrer (i),
(2) a step of continuously dispersing the polymerization initiator and the catalyst in the reaction solution with a vibration stirrer (ii),
(3) A method for producing an organic-inorganic composite hydrogel in which the steps of polymerizing the water-soluble organic monomer in the reaction liquid in which the polymerization initiator is dispersed are sequentially performed.

(Organic inorganic composite hydrogel)
The organic-inorganic composite hydrogel produced by the present invention comprises a water-swellable organic polymer, a water-swellable clay mineral that can be uniformly dispersed in water, and water as essential constituents, and the water-soluble organic polymer and the water-swellable clay mineral comprise It is a hydrogel that incorporates water in a three-dimensional network complexed at the molecular level.

(Water-soluble organic monomer having a polymerizable vinyl group)
The water-soluble organic monomer having a polymerizable vinyl group used in the present invention has a property of dissolving in water, interacts with a water-swellable clay mineral that can be uniformly dispersed in water, and can form a non-covalent bond. Those having a functional group capable of forming a hydrogen bond, an ionic bond, a coordination bond, a covalent bond and the like with a clay mineral are preferable. Specific examples of water-soluble organic monomers having these functional groups include water-soluble polymerizable unsaturated groups having amide groups, amino groups, ester groups, hydroxyl groups, tetramethylammonium groups, silanol groups, epoxy groups, and the like. Examples thereof include organic monomers. Among them, a polymerizable unsaturated group-containing water-soluble organic monomer having an amide group or an ester group is preferable. Particularly preferred are acrylamide monomers. In addition, as water used by this invention, it is a mixed solvent with the organic solvent mixed with water other than water alone, and the thing which has water as a main component is contained.

  Specific examples of the polymerizable vinyl group-containing water-soluble monomer having an amide group include acrylamides such as N-alkylacrylamide, N, N-dialkylacrylamide, and acrylamide, or N-alkylmethacrylamide, N, N-dialkylmethacrylate. And methacrylamides such as amide and methacrylamide. Here, an alkyl group having 1 to 4 carbon atoms is particularly preferably selected. Specific examples of the polymerizable vinyl group-containing water-soluble organic monomer having an ester group include methoxyethyl acrylate, ethoxyethyl acrylate, methoxyethyl methacrylate, and ethoxyethyl methacrylate.

  Examples of the polymer of the water-soluble organic monomer include a single (meth) acrylamide monomer polymer and a (meth) acrylate monomer polymer, and a plurality of different water-soluble organic monomers selected from these. It is also effective to use a copolymer obtained by polymerizing. Also, a copolymer of the above water-soluble organic monomer and other organic solvent-soluble polymerizable unsaturated group-containing organic monomer should be used as long as the obtained polymer exhibits water solubility or hydrophilicity. Can do.

  Organic solvents that are miscible with water include methanol, ethanol, propanol, glycerin, diglycerin, polyglycerin, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dimethylacetamide, dimethylformamide, Examples thereof include dimethyl sulfoxide and a mixed solvent thereof.

(Water-swelling clay mineral)
As the water-swellable clay mineral used in the present invention, those having a property of swelling in water and preferably swelling between layers by water are used. More preferably, it is a layered clay mineral that can be at least partially exfoliated and dispersed in layers in water, and particularly preferably a lamellar clay mineral that can be exfoliated and dispersed uniformly in water with a thickness of 1 to 10 layers. For example, water swellable smectite or water swellable mica is used. More specifically, water swellable hectorite containing sodium as an interlayer ion, water swellable montmorillonite, water swellable saponite, water swellable synthetic mica, etc. Is mentioned. Among them, the use of water-swellable hectorite or water-swellable saponite is preferable because the transparency of the organic-inorganic composite hydrogel is excellent.

(Polymerization initiator and polymerization catalyst)
The polymerization initiator and catalyst used in the present invention can be appropriately selected from conventional radical polymerization initiators and catalysts. Preferably, those having dispersibility in water and uniformly contained in the entire system are used. Particularly preferred is a cationic radical polymerization initiator having a strong interaction with the clay mineral exfoliated in layers. Specifically, a water-soluble peroxide as a polymerization initiator, such as potassium peroxodisulfate or ammonium peroxodisulfate, a water-soluble azo compound, for example, VA-044, V-50 manufactured by Wako Pure Chemical Industries, Ltd. V-501 or the like is preferably used. In addition, a water-soluble radical initiator having a polyethylene oxide chain is also used.

  As a catalyst, tertiary amine compounds such as N, N, N ′, N′-tetramethylethylenediamine and β-dimethylaminopropionitrile are preferably used. The polymerization temperature is set in the range of 0 ° C. to 100 ° C. according to the type of water-soluble organic polymer, polymerization catalyst and initiator used.

(Production method)
Below, preferable embodiment of the manufacturing method of this invention is described.
In the method for producing the organic-inorganic composite hydrogel of the present invention, the water-soluble organic monomer is preferably used after removing the polymerization inhibitor using an activated alumina column, the polymerization initiator is about 2%, and the catalyst is 3. It is preferable to dilute with pure water to a concentration of 2% and use it as an aqueous solution. Use pure water obtained by distilling ion-exchanged water, bubbling high-purity nitrogen in advance, and removing oxygen contained. It is preferable to do.

(Process 1)
Pure water and a water-soluble organic monomer are added to a tank whose interior is purged with nitrogen to prepare an aqueous monomer solution. Next, a water-swellable clay mineral is continuously added on the pump using a powder feeder to the monomer aqueous solution sent using the metering pump, and this mixed solution is transferred and dispersed to the vibration stirrer (i). As a result, a solution in which the water-soluble organic monomer and the water-swellable clay mineral are uniformly dispersed in water is produced.
The amount ratio of the polymer of the water-soluble organic monomer and the water-swellable clay mineral is preferably within a range in which both form a three-dimensional network in a solvent composed of water or a mixture of water and an organic solvent. The mass ratio of the mineral / water-soluble organic monomer polymer is preferably 0.01 to 3, more preferably 0.1 to 3, and particularly preferably 0.3 to 2.5. When the mass ratio is less than 0.01, it is difficult to form an effective three-dimensional network, while when it exceeds 3, it is often difficult to disperse the water-like swellable clay mineral in a layered manner.

(Process 2)
Next, a solution in which the water-soluble organic monomer and the water-swellable clay mineral prepared in Step 1 were uniformly dispersed in water was fed to the vibration stirrer (ii) and provided in the vibration stirrer (ii). The catalyst solution and the polymerization initiator solution are added and stirred from the two additive inlets. The continuously discharged reaction solution is transferred to a nitrogen-sealed polymerization vessel, and polymerization is carried out at 20 to 100 ° C. for about 10 to 30 hours.

  The amount ratio of the polymer of the water-soluble organic monomer and the polymerization initiator is preferably 0.001 to 0.10, more preferably 0.005 to 0.00 as the mass ratio of the polymerization initiator / polymer of the water-soluble organic monomer. 01. If the mass ratio is less than 0.001, it is difficult to form an effective three-dimensional network, while if it exceeds 0.10, it is often difficult to disperse the polymerization initiator in the monomer / clay solution. .

In addition, it is preferable to perform all these operations from preparation of a solution to superposition | polymerization in nitrogen atmosphere which interrupted | blocked oxygen. Within 1 to 30 hours from the start of polymerization, a colorless transparent and uniform organic-inorganic composite hydrogel having elasticity and toughness consisting of organic polymer and clay mineral is formed in the reaction vessel.
When performing a polymerization reaction, the reaction solution to which a polymerization initiator is added can be transferred into a reaction vessel having a desired shape to obtain an organic-inorganic composite hydrogel having a desired shape such as a film shape or a flat plate shape.

(Vibrating stirrer)
As the vibration stirrer used in the present invention, a known vibration stirrer can be used as long as the effects of the present invention can be obtained. Among them, the vibration stirrer (i) and the vibration stirrer (ii) are provided in one of the cylindrical casing with the upper and lower end surfaces closed, the flow passage through which the reaction liquid flows, and the upper and lower end surfaces. The reaction liquid inlet and the outlet provided on the other end face, and further disposed in the flow path, reciprocating in the flow direction of the reaction liquid, It is preferable that the apparatus includes a stirring body including a stirring blade attached around the shaft portion, and has a mechanism for stirring the reaction liquid by a stirring body that reciprocates in the flow direction of the reaction liquid.

  An example of the preferred vibratory stirrer will be described in more detail with reference to FIG. 1 includes a cylindrical casing 1 provided with a flow passage through which a reaction liquid flows, and a shaft portion 3 disposed in the casing 1 and connected to a vibration source (not shown). And an agitating and mixing apparatus having an agitating body 2 comprising a stirring blade 4 attached to the periphery of the shaft portion 3, a raw material inlet 6 for introducing the raw material into the casing 1, and an outlet 7.

By stirring the stirring body 2 with vibration (vibration direction 8), it is possible to feed the stirred object backward while performing uniform stirring. Thereby, even if the agitated material becomes highly viscous without causing secondary aggregation, the agitated material does not stay in the casing, and the agitation and mixing operation can be performed smoothly. . In the casing 1, one or more stirring chambers in which the flow path is partitioned by a partition plate 5 are provided. By providing the partition plate 5, a turbulent flow is generated in the flow passage in the casing 1, and the stirring efficiency is further improved.
As such a vibration agitating apparatus, there is a Vibro mixer (manufactured by Chilling Industries Co., Ltd.).

EXAMPLES Next, although an Example demonstrates this invention more concretely, this invention is not limited only to the Example shown below from the first.

(Raw material purification method)
As the clay mineral, a water-swellable synthetic hectorite (trademark Laponite XLG, manufactured by Rockwood Additive Co., Ltd.) having a composition of [Mg _5.34 Li _0.66 Si ₈ O ₂₀ (OH) ₄ ] Na _0.66 ⁺ is used. Using. As the water-soluble organic monomer, N, N-dimethylacrylamide (DMAA: manufactured by Kojin Co., Ltd.) was used, and the polymerization inhibitor was removed in a volume of 50 g of activated alumina column (manufactured by Wako Pure Chemical Industries, Ltd.) with respect to DMAA1L. Used from. As the polymerization initiator, potassium peroxodisulfate (KPS: manufactured by Kanto Chemical Co., Inc.) was diluted with pure water to a concentration of 2% and used as an aqueous solution. As the catalyst, N, N, N ′, N′-tetramethylethylenediamine (TEMED: manufactured by Kanto Chemical Co., Inc.) was diluted with pure water to a concentration of 3.2% and used as an aqueous solution. Pure water obtained by distilling ion-exchanged water was used as water, and high purity nitrogen was bubbled in advance to remove oxygen contained.

Example 1
A monomer aqueous solution was prepared in a pure water: DMAA 9.3: 1 ratio in a solution tank purged with nitrogen. This monomer aqueous solution was continuously supplied with stirring at 1.5 L / min using a metering pump and Laponite XLG at 46 g / min using a powder feeder while stirring and vibrated with a pump (manufactured by Hyojin Equipment Co., Ltd .; MONO pump). The mixture was continuously transferred to a mechanical stirrer (Vibro mixer M35-V1.5; manufactured by Chilling Industries Co., Ltd.). By vigorously stirring in a vibration stirrer (25 vibrations / second; stirring time 5 seconds), Laponite XLG was uniformly dispersed, and a colorless and transparent solution was continuously prepared.

  The above colorless and transparent uniform dispersion was continuously transferred to another vibratory stirrer (Vibro mixer M35-V1.5; manufactured by Kyoku Kogyo Co., Ltd.) at 1.5 L / min, and at 70 mL / min. The supplied KPS aqueous solution and the TEMED aqueous solution supplied at 35 mL / min were separately added from the two additive inlets installed in the vibration type stirrer and mixed. The reaction solution continuously discharged from the vibration type stirrer was filled in a polymerization vessel purged with nitrogen, and allowed to stand in a constant temperature water bath at 20 ° C. for 18 hours for polymerization. The operations from the preparation of the solution to the polymerization were all performed in a nitrogen atmosphere in which oxygen was blocked. 18 hours after the start of the polymerization, an elastic and tough, colorless, transparent, and uniform cylindrical polymer gel composed of organic polymer and clay mineral was formed in a sealed container. The synthesized polymer gel was a hydrogel having a water content ([water / gel dried product] × 100 =) of 760% by mass.

(Example 2)
A monomer aqueous solution was prepared in a pure water: DMAA 26.7: 1 ratio in a solution tank purged with nitrogen. This monomer aqueous solution was continuously supplied with stirring at 1.5 L / min using a metering pump and Laponite XLG at 114 g / min using a powder feeder while being stirred, and vibrated with a pump (manufactured by Hyojin Equipment Co., Ltd .; MONO pump). The mixture was continuously transferred to a mechanical stirrer (Vibro mixer M35-V1.5; manufactured by Chilling Industries Co., Ltd.). By vigorously stirring in a vibration stirrer (25 vibrations / second; stirring time 5 seconds), Laponite XLG was uniformly dispersed, and a colorless and transparent solution was continuously prepared.

  The above colorless and transparent uniform dispersion was continuously transferred to another vibratory stirrer (Vibro mixer M35-V1.5; manufactured by Kyoku Kogyo Co., Ltd.) at 1.5 L / min, and at 70 mL / min. The supplied KPS aqueous solution and the TEMED aqueous solution supplied at 35 mL / min were separately added from the two additive inlets installed in the vibration type stirrer and mixed. The reaction solution continuously discharged from the vibration type stirrer was filled in a polymerization vessel purged with nitrogen, and allowed to stand in a constant temperature water bath at 20 ° C. for 18 hours for polymerization. The operations from the preparation of the solution to the polymerization were all performed in a nitrogen atmosphere in which oxygen was blocked. 18 hours after the start of the polymerization, an elastic and tough, colorless, transparent, and uniform cylindrical polymer gel composed of organic polymer and clay mineral was formed in a sealed container. The synthesized polymer gel was a hydrogel having a water content ([water / gel dried product] × 100 =) of 855 mass%.

(Comparative Example 1)
18.5 kg of pure water and 1.98 kg of DMAA are added to a stainless steel container (the bottom is curved, the inner diameter is 30 cm, the height is 40 cm), and Laponite XLG 0.64 kg is added to the anchor blade (blade diameter: 20 cm, high height). (5 cm × 2 stages) with vigorous stirring (200 rpm) for 1 minute. It took 15 minutes to obtain a clear and colorless solution. Thereafter, 0.5 kg of the TEMED solution was added to prepare a dispersion of Laponite XLG (adjustment liquid). 1 kg of an aqueous KPS solution was added to the above prepared solution, and left standing in a constant temperature water bath at 20 ° C. It took 2 minutes from the addition of KPS until the polymerization started and the viscosity increased.

(Comparative Example 2)
Pure water 18.5 kg and DMAA 0.69 kg are added to a stainless steel container (bottom surface is curved, inner diameter 30 cm, height 40 cm) with nitrogen inside, and Laponite XLG 1.60 kg is added to the anchor blade (blade diameter: 20 cm, high (5 cm × 2 stages) with vigorous stirring (200 rpm) for 1 minute. Stirring was continued for 30 minutes, but the water-swollen laponite XLG hardened and a colorless and transparent solution could not be obtained.

(Comparative Example 3)
The prepared solution in the stainless steel container prepared in Comparative Example 1 was transferred to a static mixer (N40, manufactured by Noritake Co., Ltd., N40; inner diameter 11 mm, length 200 mm) at 1.5 L / min, and supplied at 70 mL / min. And mixing. The reaction solution continuously discharged from the static mixer was filled in a sealed tank whose interior was purged with nitrogen, and allowed to stand in a constant temperature water bath at 50 ° C. for 18 hours for polymerization. The operations from the preparation of the solution to the polymerization were all performed in a nitrogen atmosphere in which oxygen was blocked. 18 hours after the start of the polymerization, an elastic and tough, colorless, transparent, and uniform cylindrical polymer gel composed of organic polymer and clay mineral was formed in a sealed container. The synthesized polymer gel was a hydrogel having a water content ([water / gel dried product] × 100 =) of 760% by mass.

(Evaluation method of residual monomer amount)
The amount of residual monomer of the organic-inorganic composite hydrogel produced in each example and comparative example was measured by the following method. The measured values are summarized in Table 1. The synthesized hydrogel (2.0 g) and pure water (100 g) were placed in a mixer (Oster Blender; manufactured by Osaka Chemical Co., Ltd.) and treated at 15700 rpm for 5 minutes to obtain a gel slurry. This slurry was heated and stirred at 80 ° C. for 1 hour to prepare an extract. After cooling the extract, the gel component was removed with a membrane filter (pore size: 0.45 μm), and HPLC (Nippon Waters, Separation Module 2695, UV Detector 2487; Column: Inertsil ODS-3, GL Sciences Inc. 4.6 mm ID × 250 mm; elution solvent composition: acetonitrile / water = 20/80; detection wavelength: 230 nm), and the residual DMAA monomer was quantified by a one-check calibration method.

(Use of organic-inorganic composite hydrogel produced in the present invention)
The obtained organic-inorganic composite hydrogel has excellent transparency, mechanical properties, etc., taking advantage of its characteristics, in a wide range of daily necessities, medicine / medical, agriculture, civil engineering, industrial fields, etc., especially vibration absorbing materials, It is a material useful for stretching device component materials, artificial organ materials, therapeutic materials, optical materials, and the like.

It is sectional drawing which shows an example of the vibration type stirrer used by this invention. It is the schematic which shows the whole continuous manufacturing process of this invention.

Explanation of symbols

1: Casing 2: Stirring body 3: Shaft 4: Stirring blade 5: Partition plate 6: Inlet 7: Outlet 8; Direction of vibration

Claims (1)

A step of continuously dispersing a water-soluble organic monomer having a polymerizable vinyl group and a water-swellable clay mineral in water using a vibration stirrer (i) to produce a reaction solution,
A step of continuously dispersing a polymerization initiator in the reaction solution by a vibration stirrer (ii),
A method for producing an organic-inorganic composite hydrogel that sequentially performs a step of polymerizing the water-soluble organic monomer in a reaction solution in which the polymerization initiator is dispersed,
The vibration stirrer (i) and the vibration stirrer (ii) are
A cylindrical casing with the upper and lower end surfaces closed, a flow passage through which the reaction solution flows, an inlet for the reaction solution provided on one of the upper and lower end surfaces, and an end surface provided on the other end surface An outlet and
Furthermore, it is disposed in the flow passage and is capable of reciprocating in the flow direction of the reaction solution, and includes a stirring body including a shaft portion and a stirring blade attached around the shaft portion,
A method for producing an organic-inorganic composite hydrogel, comprising a mechanism for stirring the reaction liquid by a stirring body that reciprocates in the flow direction of the reaction liquid.

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