JP5501012B2 - ORGANIC-INORGANIC COMPOSITE GEL HAVING REPEATED CONCRETE PROFILE ON THE SURFACE AND METHOD FOR PRODUCING THE SAME - Google Patents

Description

  The present invention relates to an organic / inorganic composite gel comprising a polymer and inorganic particles and a method for producing the same.

  A polymer hydrogel composed of a polymer and water has been considered for many uses as a transparent and soft material and a highly water-absorbing material (Non-patent Document 1). However, the conventional polymer hydrogel composed of a three-dimensional polymer network by chemical crosslinking has a problem that it is mechanically fragile and difficult to handle. In contrast, organic / inorganic composite hydrogels with high transparency, high water absorption and extremely good mechanical properties have been developed by building an organic / inorganic three-dimensional network consisting of polymer and layered clay minerals. (Patent Document 1). It has also become possible to replace the medium (water) with a low-volatile medium (eg, glycerin) (Patent Document 2). Such organic / inorganic composite gels are generally transparent and have a smooth surface. In particular, when the network density is low (eg, when the clay content is low), the organic / inorganic composite gel often exhibits sticky surface characteristics. However, for example, when the organic / inorganic composite gel is used as a film, a sheet, a block molded body or the like, a feature excellent in slipperiness is often required for contact with other materials.

JP 2002-53629 A JP 2006-028446 A

"Gel Handbook" p226-727, Yoshihito Nagata, Satoshi Sugawara: NTN Corporation, 1997

  The problem to be solved by the present invention is to provide an organic-inorganic composite gel with improved surface slip and a method for producing the same.

As a result of diligent research to solve the above problems, the present inventors have obtained an aqueous solution containing a water-soluble radical polymerizable organic monomer and a finely dispersed water-swellable clay mineral, at least a part of the substrate surface, It is injected into a container made of a base material having an oxygen permeability of 10 cc · 20 μ / m ² / day · atm or more, or is brought into contact with a gas having an oxygen concentration of 10 ppm or more, and the water-soluble radical polymerizability. After the organic monomer is polymerized to prepare an organic / inorganic composite gel, the organic / inorganic composite gel is stretched at a stretch ratio that does not break the gel between 1.5 times and 15 times. It has been found that striped repeated irregularities are formed on the gel surface, and that the organic / inorganic composite gel having the irregular surface has excellent surface slipperiness, leading to the completion of the present invention. It was.

  That is, the present invention is an organic-inorganic composite gel having a three-dimensional network structure formed of a polymer (A) of a water-soluble radical polymerizable organic monomer and a water-swellable clay mineral (B). Provided is an organic-inorganic composite gel having a repeated uneven structure.

In addition, the present invention provides an aqueous solution containing a water-soluble radically polymerizable organic monomer (A) and a water-swellable clay mineral (B) exfoliated in layers, part or all of which is 10 cc · 20 μ / m ² / day · atm or more. The organic inorganic composite gel was prepared by polymerizing the water-soluble radically polymerizable organic monomer (A) and injecting it into a container made of a substrate having an oxygen permeability of 1.5%. Production of an organic-inorganic composite gel having a repeated concavo-convex structure on the surface, wherein the concavo-convex structure is repeatedly expressed on the surface of the gel obtained by contact with the substrate by stretching to 15 to 15 times Provide a method.

Furthermore, the present invention provides an aqueous solution containing a water-soluble radically polymerizable organic monomer (A) and a layer-peeled water-swellable clay mineral (B) in contact with a gas having an oxygen concentration of 10 ppm or more. An organic-inorganic composite gel by polymerizing a polymerizable radical polymerizable organic monomer (A),
The resulting organic / inorganic composite gel is stretched 1.5 times to 15 times, and the surface of the gel in contact with the gas is allowed to develop a repetitive uneven structure. A method for producing an inorganic composite gel is provided.

  The surface unevenness-containing organic / inorganic composite gel obtained by the present invention exhibits excellent surface slipperiness compared to an organic / inorganic composite gel having a smooth surface without it. The surface uneven organic / inorganic composite gel obtained by the present invention has the characteristics of excellent slipperiness in the objective and the human as well as the characteristics of the conventional organic / inorganic composite gel, for industrial use, medical use, cosmetic use, and electronic parts. It is used effectively in a wide range of fields such as construction.

It is a figure which shows the repetitive striped uneven structure on the stretched gel surface obtained in Example 2.

  The organic / inorganic composite gel in the present invention comprises a polymer obtained from a water-soluble radically polymerizable organic monomer (hereinafter referred to as a water-soluble radically polymerizable organic monomer polymer) and a water-swellable clay mineral peeled in layers. It is compounded at the molecular level, forms a three-dimensional network by any of hydrogen bonds, ionic bonds, coordinate bonds, covalent bonds, and the like, and contains water and / or a low-volatile medium as a medium. This is because the composite gel swells with water or a hydrophilic organic solvent, and even if the composite gel is treated at 20 ° C. for 500 hours or more, the water-swellable clay mineral and the water-soluble radical polymerizable organic monomer are constituents. This is confirmed by the fact that the polymer is not extracted and exhibits a large reversible stretchability and compressibility in a mechanical test of stretching and compression.

  As the water-soluble radically polymerizable organic monomer (A) in the present invention, those having a property of dissolving in water and interacting with a water-swellable clay mineral (B) that can be uniformly dispersed in water are preferable. Those having a functional group capable of forming a hydrogen bond, an ionic bond, a coordinate bond, a covalent bond and the like with the clay mineral are preferable. Specific examples of water-soluble radically polymerizable organic monomers (A) having these functional groups include amide groups, amino groups, ester groups, hydroxyl groups, tetramethylammonium groups, silanol groups, and epoxy groups. Radical water-polymerizable organic monomers having an amide group or an ester group are preferable. In addition, the water said by this invention contains what has water as a main component in the mixed solvent with the organic solvent miscible with water other than water alone.

  Specific examples of the water-soluble radically polymerizable organic 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 water-soluble radically polymerizable organic monomer containing a polymerizable unsaturated group having an ester group include methoxyethyl acrylate, ethoxyethyl acrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate and the like.

  Examples of such water-soluble radically polymerizable organic monomer polymers include poly (N-methylacrylamide), poly (N-ethylacrylamide), poly (N-cyclopropylacrylamide), poly (N-isopropylacrylamide), and poly (N-isopropylacrylamide). (Acryloylmorpholine), poly (methacrylamide), poly (N-methylmethacrylamide), poly (N-cyclopropylmethacrylamide), poly (N-isopropylmethacrylamide), poly (N, N-dimethylacrylamide), Poly (N, N-dimethylaminopropylacrylamide), poly (N-methyl-N-ethylacrylamide), poly (N-methyl-N-isopropylacrylamide), poly (N-methyl-Nn-propylacrylamide), Poly (N, N-diethylacrylate) Amide), poly (N-acryloylpyrrolidine), poly (N-acryloylpiperidine), poly (N-acryloylmethylhomopiperazine), poly (N-acryloylmethylpiperazine), poly (acrylamide), poly (acrylamide) Examples include methoxyethyl acrylate), poly (ethoxyethyl acrylate), poly (methoxyethyl methacrylate), and poly (ethoxyethyl methacrylate). The water-soluble radical-polymerizable organic monomer polymer includes a polymer from a single water-soluble radical-polymerizable organic monomer as described above, and a water solution containing a plurality of different polymerizable unsaturated groups selected from these. It is also effective to use a copolymer obtained by polymerizing a polymerizable radical polymerizable organic monomer. Also, a copolymer of the water-soluble radical polymerizable organic monomer and other organic solvent-soluble polymerizable unsaturated group-containing organic monomer (for example, acrylate or methacrylate having a polyethylene glycol chain having a different chain length in the side chain) As long as the integrated polymer gel according to the present invention can be achieved, it can be used.

  The water-soluble radical-polymerizable organic monomer polymer in the present invention is obtained by polymerizing the water-soluble radical-polymerizable organic monomer (A), and is hydrophilic (or amphiphilic) having a water-soluble or water-absorbing property. ). Furthermore, those having functionality such as response to heat, pH and light, and biocompatibility including bioabsorbability and biodegradability are more preferably used depending on the application. For example, water-soluble radical-polymerizable organics that have properties that polymer properties (eg, hydrophilicity and hydrophobicity) in aqueous solutions vary greatly with slight temperature changes before and after the lower critical solution temperature (LCST) Examples of the monomer polymer include poly (N-isopropylacrylamide) and poly (N, N-diethylacrylamide). Examples of biocompatibility include poly (methoxyethyl acrylate) and poly (methacrylamide).

  The clay mineral used for the organic / inorganic composite gel in the present invention is a water-swellable clay mineral (B) having a swellability in water, and preferably has a property of swelling between layers by water. 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.

  In the present invention, the mass ratio (B / A) of the water-swellable clay mineral (B) to the water-soluble radically polymerizable organic monomer polymer (A) is preferably 0.05 to 2.0, more preferably. Is 0.07 to 1.0, particularly preferably 0.1 to 0.7. If it is 0.05 or less, the strength of the integrated polymer gel obtained is often weak, and if it is 2.0 or more, integration becomes difficult to proceed.

  The organic-inorganic composite gel of the present invention contains water, but may contain a medium that is less volatile than water in addition to water. In this case, part or all of the water contained in the gel may be replaced with a low-volatile medium.

  The low volatility medium used in the present invention is an organic molecule or organic polymer having a lower volatility than water that can be dissolved or mixed in water. Specifically, it is an organic molecule having a hydrophilic functional group such as an ether group, a hydroxyl group, a carboxyl group, an amide group, an amino group, for example, ethylene glycol, propylene glycol, diethylene glycol, glycerin, polyethylene glycol, polypropylene glycol, 1,3 butylene glycol etc. are mentioned. These can be used alone or in combination. As a method of including a medium other than water in the organic / inorganic composite gel, it is possible to coexist with water in an aqueous solution containing a water-soluble radical polymerizable organic monomer and a water-swellable clay mineral, After the three-dimensional network is formed, a method of replacing part or all of the aqueous medium with the low-volatile medium, and further, from the obtained organic / inorganic composite gel in which the water and the low-volatile medium coexist, And a method of volatilizing a part or all of the above. In addition, in addition to the organic / inorganic three-dimensional network and the medium, a polymer having a hydrophilic functional group can coexist. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, poly (hydroxyethyl acrylate), poly (hydroxyethyl methacrylate), poly (N-methylacrylamide), poly (N-ethylacrylamide), poly (N-isopropylacrylamide), poly (Acryloylmorpholine), poly (N, N-dimethylacrylamide), poly (acrylamide), polyacrylic acid, hyaluronic acid, polyethyleneimine, polypropyleneimine, agarose, alginic acid, carrageenan, collagen, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose , Cellulose derivatives, chitansan gum, gellan gum, chitosan and the like.

  The surface unevenness in the present invention has a repetitive uneven structure on the micrometer level (1 to 1000 microns), and more preferably has a width of 10 to 500 microns and a height of 50 to 1000 microns. The surface portion has a striped repeated concavo-convex structure. The striped pattern means a pattern in which lines having long straight lines, curved lines, or both are arranged like a row, and can be said to be a striped pattern.

  Such surface irregularities may be present on the entire surface or a part of the organic / inorganic composite gel, and various kinds of surface irregularities are produced and used depending on the purpose. For example, in an organic / inorganic composite gel film or sheet, all of the upper and lower surfaces have surface unevenness, only the upper surface or lower surface has surface unevenness, or only one or both surfaces have surface unevenness Used effectively. Further, a surface irregularity-containing region and a smooth region, which are formed at regular intervals, can be effectively used depending on the purpose.

  As the method for producing an organic / inorganic composite gel having surface irregularities in the present invention, an aqueous solution containing a water-soluble radical polymerizable organic monomer (A) and a finely dispersed water-swellable clay mineral (B) is used. It is injected into a container made of a substrate having high properties, and the water-soluble radically polymerizable organic monomer (A) is polymerized to prepare an organic / inorganic composite gel, or a gas containing oxygen and an aqueous solution are brought into contact with each other. In this state, the water-soluble radically polymerizable organic monomer (A) is polymerized to prepare an organic / inorganic composite gel, and the obtained organic / inorganic composite gel is stretched. Moreover, by using a container in which a base material having a high oxygen permeability and a base material having a low oxygen permeability are used, an organic / inorganic composite gel partially having a surface uneven structure is obtained by the same organic / inorganic composite gel synthesis and subsequent stretching treatment. Is manufactured.

As the base material of the container used in the present invention, it is necessary to use a base material having an oxygen permeability sufficient to form surface irregularities by subsequent stretching treatment, and preferably 10 cc · 20 μ / m ² / It is a base material having an oxygen permeability of not less than day · atm, more preferably not less than 100 cc · 20 μ / m ² / day · atm, and particularly preferably not less than 1000 cc · 20 μ / m ² / day · atm. Specific examples include polyethylene, polypropylene, polymethyl methacrylate, polystyrene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, nylon 6, and epoxy resin. In addition to the high oxygen permeability, the use of a base material having a high oxygen adsorptivity that can give a similar amount of oxygen to the gel surface during polymerization produces the same effect and is effectively used. On the other hand, a substrate having a lower oxygen permeability than the above is used for the preparation of an organic / inorganic composite gel having a smooth surface with little or no unevenness even after stretching. The oxygen permeability is preferably 10 cc · 20 μ / m ² / day · atm or less, more preferably 1 cc · 20 μ / m ² / day · atm or less, particularly preferably 0.1 cc · 20 μ / m ² / day · atm. Specifically, glass, quartz, stainless steel, aluminum vapor deposition film / sheet, silica vapor deposition film / sheet, gas barrier polymer resin (biaxially stretched PVA, transparent vapor deposition PET / nylon 6 / PP laminate resin) and the like Inorganic vapor deposition film. In addition, the container produced using these 1 type or several base materials can be arbitrarily designed irrespective of a magnitude | size and a shape.

  In the present invention, the water-soluble radical-polymerizable organic monomer (A) is polymerized in a state of contact with a gas containing oxygen to prepare an organic / inorganic composite gel, and then a production method in which a stretching process is performed is also effectively used. It is done. In this case, the amount of oxygen contained in the gas is not limited as long as a satisfactory organic / inorganic composite gel is formed and sufficient oxygen is formed to form surface irregularities by subsequent stretching treatment. Although it varies depending on the thickness and polymerization conditions and is not necessarily limited, it is preferably 10 ppm or more, more preferably 100 ppm or more. However, if the oxygen concentration is too high, the polymerization may be incomplete.

  The stretching treatment is performed by stretching once or a plurality of times within a range of a stretching ratio that does not break the organic / inorganic composite gel. The stretching ratio is preferably 1.5 to 15 times. If it is 1.5 times or less, effective surface unevenness may not be produced, and if it is 15 times or more, unnecessary permanent distortion may appear, resulting in inconvenience. The reason why micrometer level irregularities are formed by such stretching treatment is not necessarily clear. Presumably, the formation of organic / inorganic three-dimensional network structure is partially inhibited by oxygen contained in or on the container surface, oxygen passed through the container base material, or oxygen contained in the gas in contact Since it is weakened, it is presumed that the three-dimensional network of the part is partially broken by the subsequent stretching process to form an uneven structure.

  Furthermore, in the present invention, it is possible to produce a surface irregularity-containing organic / inorganic composite gel using water as a medium, a low-volatile medium as described above, or a mixed medium of water and a low-volatile medium. . As a method of changing all or part of the water into a low-volatile medium, a method of including a low-volatile medium in an aqueous solution before polymerization, a low volatility after preparing an organic / inorganic composite gel using water as a medium A method of replacing the medium and a method of volatilizing water by drying them are used. These medium treatment and stretching treatment can be produced regardless of which one is performed first.

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

(Examples 1-4 and Comparative Example 1)
60 g of pure water, 1.372 g of water-swellable clay mineral (Hectorite: Trademark Laponite XLG), 5.94 g of water-soluble radically polymerizable organic monomer (N, N-dimethylacrylamide (DMAA)), polymerization initiator (peroxo In Examples 1, 2, and 3, a uniform and transparent aqueous solution composed of 0.06 g of potassium sulfate (KPS) was used. One was a glass substrate and the other was polycarbonate (PC) (oxygen permeability = 4500 cc · 20 μ / m ² / day / atm) Thin film preparation container made of base material (internal shape: length 130 mm, width 230 mm, height 2 mm). In Example 4, both were poured into a thin film preparation container made of PC base material and polymerized at 50 ° C. for 5 hours. Was done. As a result, in both cases, an organic / inorganic composite gel that was uniform and transparent and had a smooth surface was obtained. The obtained organic / inorganic composite gel was stretched 3.5 times in Example 1, 7 times in Examples 2 and 4, and 12 times in Example 3. As a result, in Examples 1, 2, and 3, the surface unevenness organic / inorganic composite in which only one surface (the gel surface prepared in contact with the PC base material surface) has linear repetitive unevenness in the direction perpendicular to the stretching direction. A gel was obtained. An example of surface irregularities of Example 2 measured using an optical microscope is shown in FIG. The average surface roughness was 220 μm in width, 60 μm in height (Example 1), 140 μm in width, 80 μm in height (Example 2), 110 μm in width, and 100 μm in height (Example 3). The surface slip characteristics of the organic / inorganic composite gel having surface irregularities were measured using a small glass plate (1.5 cm width × 2 cm length × 0.3 cm thickness). Specifically, on the surface of the organic / inorganic composite gel having surface irregularities, a small glass plate loaded with a load of 9 g / cm ² is pulled in the horizontal direction, and the dynamic friction force (0.02 N in Example 1) is obtained from the necessary force at that time. In Example 2, 0.01N, and in Example 3, 0.005N) were obtained. On the other hand, the gel surface (Comparative Example 1) prepared by contacting with the glass substrate surface was smooth. In the measurement of the slip characteristics of the smooth surface, 0.12 N was obtained as the dynamic friction force in each of Examples 1 to 3. On the other hand, in Example 4, both gel surfaces were organic / inorganic composite gels having surface irregularities, and a dynamic friction force of 0.01 N was obtained.

(Examples 5 and 6)
The amount of Laponite XLG is 0.914 g, hard vinyl chloride (oxygen permeability = 130 cc · 20 μ / m ² / day · atm) is used instead of PC, polyethylene terephthalate / nylon 6 / In the same manner as in Example 1, except for using a polypropylene laminated silica transparent vapor deposition film, and stretching is performed 3 times in Example 5 three times, and in Example 6 is performed 12 times stretched once, surface irregularities and The dynamic friction force was measured. In any case, linear irregularities were repeatedly formed on the gel surface using the hard vinyl chloride base material. In Example 5, the width was 105 μm, the height was 100 μm, and in Example 6, the width was 80 μm and the height was 130 μm. Moreover, all the gel surfaces using a silica transparent vapor deposition film base material were smooth. The dynamic friction force was 0.005 N in Example 5 and 0.004 N in Example 6.

(Example 7)
Add 48 μl of a polymerization accelerator (N, N, N ′, N′-tetramethylenediamine) to a uniformly transparent aqueous solution, set the polymerization temperature / time to 20 ° C./20 hours, the height of the thin film preparation container An organic / inorganic composite gel was prepared in the same manner as in Example 2 except that the reaction aqueous solution was filled up to 1 mm and nitrogen gas containing 300 ppm of oxygen was introduced as a gas. Then, as a result of performing the extending | stretching process to 7 time, the linear unevenness | corrugation (width 200 micrometers, height 100 micrometers) structure was repeatedly formed in the gel surface which faced the gas, and the dynamic friction force was 0.018N.

(Example 8 and Comparative Example 2)
The organic / inorganic composite gel obtained in Example 1 was immersed in a glycerin aqueous solution composed of glycerin (80 g) and water (50 g), and then dried at room temperature for 20 hours, whereby organic / substantially substituted medium was replaced with glycerin. An inorganic composite gel was obtained. Then, as a result of performing the extending | stretching process to 8 times, the linear unevenness | corrugation (width 180 micrometers, height 100 micrometers) structure was repeatedly formed in the gel surface which faced the PC base material, and the dynamic friction force was 0.04N. On the other hand, the gel surface (Comparative Example 2) prepared facing the glass substrate was smooth, and the dynamic friction force was 0.25N.

Claims (3)

A part or all of the aqueous solution containing the water-soluble radically polymerizable (meth) acrylamide organic monomer (A) and the layered exfoliated water-swellable clay mineral (B) is 10 cc · 20 μ / m ² / day · atm or more . Yes, it is injected into a container made of a base material having an oxygen permeability of 4500cc · 20μ / m ² / day · atm or less , and the water-soluble radical polymerizable organic monomer (A) is polymerized to prepare an organic-inorganic composite gel. And, by stretching the obtained organic-inorganic composite gel 1.5 to 15 times, it is characterized in that a concavo-convex structure is repeatedly expressed on the surface of the gel obtained in contact with the substrate, A method for producing an organic-inorganic composite gel having a concavo-convex structure on its surface. A state in which an aqueous solution containing a water-soluble radically polymerizable (meth) acrylamide organic monomer (A) and a layered exfoliated water-swellable clay mineral (B) is brought into contact with a gas having an oxygen concentration of 10 ppm or more and 300 ppm or less Then, the water-soluble radically polymerizable organic monomer (A) is polymerized to prepare an organic-inorganic composite gel, and the obtained organic-inorganic composite gel is stretched 1.5 times to 15 times to produce gas and A method for producing an organic-inorganic composite gel having a repeated concavo-convex structure on a surface, wherein the concavo-convex structure is repeatedly exhibited on the surface of the gel contacted. 3. The organic-inorganic composite having a repetitive uneven structure on the surface according to claim 1, wherein the repetitive uneven structure is a striped uneven structure having a width of 10 to 500 microns and a height of 50 to 1000 microns. A method for producing a gel.

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