JP2011140651A - Method for using polyvinyl alcohol-based hydrogel, and application thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for using a polyvinyl alcohol-based composition and a polyvinyl alcohol-based hydrogel which are excellent in workability because forming a gel in several minutes to several days even in being left at rest outdoor, and in which an obtained hydrogel has water resistance even in an acidic region; and to provide applications thereof. <P>SOLUTION: There are provided the method of use of and applications of the polyvinyl alcohol-based hydrogel, which is formed from a composition for forming a gel having main constituents of a polyvinyl alcohol (A), a water-soluble organotitanium compound (B) and water (C), wherein (1) the water-soluble organotitanium compound (B) is a titanium compound containing an aminoalcohol as a component of a chelate-type ligand, (2) the proportion of (A) to the total amount of (A), (B) and (C) is 0.5 to 10 mass%, (3) the molar ratio (A):(B) of a vinyl alcohol unit of (A) to a titanium atom contained in the (B) component is 1:0.01 to 1.0, and (4) the degree of polymerization of (A) is ≥500, and which is used for civil engineering materials, building materials, agricultural and aquacultural materials, water quality cleaning materials, cooling media at human fever, artificial false baits, and toys. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyvinyl alcohol-based hydrogel-forming composition and hydrogel containing polyvinyl alcohol (hereinafter sometimes simply referred to as PVA), a water-soluble transition metal compound, and water as main components. More specifically, it is obtained from a composition that forms a polyvinyl alcohol hydrogel having a high water content, excellent elastic strength, water permeability, and water resistance in an acidic region by allowing it to stand at room temperature for several minutes to several days. The present invention relates to a method of using a polyvinyl alcohol hydrogel and its use.

  As a method for obtaining a polyvinyl alcohol hydrogel, (1) a method for obtaining a gel by repeating freezing and thawing in a PVA aqueous solution (for example, see Patent Document 1), (2) boric acid or the like is mixed in the presence of alkali. A method for obtaining a gel (for example, see Patent Document 2), (3) A method for obtaining a gel by coagulating a PVA aqueous solution in a high-concentration salt solution and then subjecting it to formalization in the presence of an acid (for example, see Patent Document 3). (4) A method of crosslinking the PVA molecule by irradiating the PVA aqueous solution with an electron beam, radiation or the like (for example, see Patent Literature 4 and Patent Literature 5) and (5) PH adjustment by adding trimethylolmelamine to the PVA aqueous solution. Thereafter, a method of obtaining a gel by leaving it for several hours (see, for example, Patent Document 6) is known.

When polyvinyl alcohol hydrogel is used for civil engineering applications as a water barrier or vibration absorber, or for agricultural applications as a ground improvement material, a certain amount of liquid composition is injected or mixed into the ground or ground. It is necessary to gradually advance the gelation reaction after a lapse of time from minutes to several tens of hours to form a final polyvinyl alcohol-based hydrogel.
However, the method of Patent Document 1 cannot process a large-capacity gel. The method of Patent Document 2 must use a PVA aqueous solution having a relatively high concentration, and a gel is formed almost simultaneously with the addition of boric acid. Therefore, there is a problem in workability when applied to civil engineering and agricultural uses.
On the other hand, since the method of Patent Document 3 requires a solidification step, it is difficult to apply to a shape having a small specific surface area, and is unsuitable for civil engineering and agricultural uses. The methods of Patent Document 4 and Patent Document 5 are also unsuitable for civil engineering / agricultural applications due to apparatus limitations and instantaneous bridge formation. Furthermore, in the method of Patent Document 6, the time required for gel formation is about several hours to several days. However, the water resistance in the acidic region is low, and there is a problem that the gel elutes when contacted with acidic water.

JP-A-64-43188 JP-A-6-57012 JP 9-124731 A JP-A-7-255941 Japanese Patent Laid-Open No. 11-157202 JP 2002-294014 A

  In view of the above situation, the present invention is excellent in workability because it forms a gel in several minutes to several days even when left outdoors, and the obtained hydrogel has a polyvinyl alcohol composition having water resistance even in an acidic region. It aims at providing the usage method and its use of the polyvinyl alcohol-type hydrogel obtained from a thing.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have developed a specific polyvinyl alcohol mainly composed of polyvinyl alcohol (A), a water-soluble organic titanium compound (B) and water (C). The present inventors have found that the system composition meets the above-mentioned purpose, has excellent water resistance even in acidic water, and has particularly suitable properties for civil engineering, agriculture, etc., and has reached the present invention.

That is, this invention provides the usage method and use of the polyvinyl alcohol-type hydrogel formed from the following composition for hydrogel formation.
(1) Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A: B) of the vinyl alcohol unit (A) to the transition metal atom contained in the component (B) is 1: 0.01 to 1.0,
4) Hydrogel formed from a gel-forming composition having a degree of polymerization of 500 or more in (A) is a civil engineering material, building material, agricultural / fishery material, water purification material, refrigerant during heating of human body, artificial artificial bait or A method of using a polyvinyl alcohol-based hydrogel, characterized by being used for a toy.
(2) In a penetration test in which a metal rod having a diameter of 3.5 mm is penetrated at a speed of 10 mm / min onto a hydrogel obtained by holding the gel-forming composition in a container at 20 ° C. for 7 days, when the penetration is 10 mm The method of using the polyvinyl alcohol hydrogel according to (1), wherein the penetration strength obtained by dividing the stress of 1 by the cross-sectional area of the metal rod is 1 to 200 kPa.
(3) Plug the bottom of a glass tube having a length of 1 m or more, put the composition for gel formation so as to have a thickness of 2 cm thereon, and maintain it at 20 ° C. for 7 days. After water was put on the hydrogel to a height of 100 cm, the water level h (cm) after removing the stopper at the bottom of the glass tube and allowed to stand for 5 days was measured, and the water permeability obtained by the following formula (1) was 1 × The method for using the polyvinyl alcohol hydrogel according to (1), which is 10 ⁻⁵ cm / sec or less.
Water permeability (cm / sec) =
2 × ln (100 / h) / (5 × 24 × 3600) (1)
(In the formula, ln represents a natural logarithm.)
(4) After immersing the polyvinyl alcohol hydrogel in an aqueous solution of pH 2 at a bath ratio of 1: 100 (weight of polyvinyl alcohol hydrogel: weight of aqueous solution of pH 2) at 20 ° C. for 7 days, the following formula (2) The method for using the polyvinyl alcohol-based hydrogel according to (1), wherein the obtained polyvinyl alcohol (A) has a weight retention rate (Wab) of 70% or more.
Wab (% by weight) = 100− [10000 × (Wb) / (Wa)] (2)
(Wab represents the weight retention of polyvinyl alcohol (A), Wa represents the initial solid content concentration (wt%) of the hydrogel, and Wb represents the solid content concentration (wt%) after immersion for 7 days at 20 ° C. )

  The composition for forming a polyvinyl alcohol-based hydrogel of the present invention forms a gel in a few minutes to a few days even when left outdoors, so that it is excellent in workability and forms a hydrogel having water resistance even in an acidic region. The obtained polyvinyl alcohol-based hydrogel has a high water content, excellent elastic strength, and excellent water permeability, and is suitably used as a material for civil engineering, construction, agriculture, fisheries, etc. It can also be used for refrigerants, artificial artificial baits, toys, etc. when generating heat.

The PVA of the component (A) used in the present invention is not particularly limited, but may be modified or copolymerized with other components in the polymerization step or the like. For example, ethylene-modified, silane-modified, alkyl ether-modified, carboxyl-modified, itaconic acid-modified, hydrophobic group-modified, or the like, or vinyl acetate and components typified by ethylene may be copolymerized.
The degree of polymerization of PVA needs to be 500 or more, preferably 1000 or more, more preferably 1500 or more in order to greatly influence the elastic strength, water permeability and water resistance of the resulting hydrogel. This degree of polymerization is measured according to JIS K6726, and is determined from an intrinsic viscosity measurement measured in water at 30 ° C. using a re-saponified and purified PVA.

  The saponification degree of the polyvinyl alcohol (PVA) as the component (A) used in the present invention is not particularly limited, but is usually 80 to 99.99 mol%, preferably 85 to 99.95 mol. %, More preferably 90 to 99.9 mol%. By setting the saponification degree of PVA to 80 mol% or more, the elastic strength, water permeability, and water resistance are not lowered. PVA having a saponification degree of 99.99 mol% or less is industrially produced and is advantageous in terms of cost. The saponification degree is measured according to JIS K6726.

  The proportion of (A) in the total amount of PVA (A), water-soluble transition metal compound (B) and water (C) constituting the composition for forming a polyvinyl alcohol gel of the present invention is 0.5 to 10% by mass. Preferably, it is 1-7 mass%. When the ratio of (A) is 0.5% by mass or more, an appropriate water ratio is maintained, so that the gel-like product has high elastic strength, and water permeability and water resistance are good. On the other hand, at 10% by weight or less, the workability is good because the solution viscosity is small.

The water-soluble transition metal compound (B) used in the composition for forming a polyvinyl alcohol gel of the present invention may be an organic compound that reacts with PVA in water to form a crosslinked structure in PVA, such as a titanium compound and a zirconium compound. , Vanadium compounds, zinc compounds, chromium compounds, nickel compounds, palladium compounds, and the like.
These water-soluble transition metal compounds (B) have a chelate-type ligand capable of coordinating in a bidentate or higher multidentate manner with a covalent bond or a hydrogen bond to one metal atom. It is preferable. Since the transition reaction rate of PVA is moderately adjusted by having a chelate type ligand in the transition metal compound, it is considered that a gelation rate of several hours to several days suitable for construction can be obtained.
Specific examples of the chelate-type ligand include hydroxycarboxylic acid or a salt thereof, amino alcohol, and β-diketone, but are not limited thereto.

Of these water-soluble transition metal compounds (B), organic titanium compounds and organic zirconium compounds are preferably used.
That is, suitable titanium compounds and zirconium compounds are titanium compounds or zirconium compounds containing one or more selected from hydroxycarboxylic acids or salts thereof, amino alcohols and β-diketones as one component of a chelate ligand. is there.
Here, examples of the hydroxycarboxylic acid include glycolic acid, lactic acid, malic acid, citric acid, tartaric acid, and salicylic acid. Examples of amino alcohols include trimethanolamine and triethanolamine, and examples of β-diketone include acetylacetone.
Specific examples of the preferred titanium compound include titanium lactate, dihydroxy titanium bis (lactate), dihydroxy titanium bis (glycolate) dihydroxy bis (lactate), titanium lactate ammonium salt, titanium diammonium, dihydroxy bis (slate) titanium. Ammonium, diisopropoxytitanium bis (triethanolamate), di-n-butoxytitanium bis (triethanolamate), diisopropoxytitanium bis (triethanolamate), titanium tetrakis (acetylacetonate) and the like can be mentioned.
Specific examples of the suitable zirconium compound include monohydroxytris (lactate) zirconium ammonium, tetrakis (lactate) zirconium ammonium, and monohydroxytris (slate) zirconium ammonium.
Said suitable titanium compound can be obtained by making the titanium chelate compound synthesize | combined from said hydroxycarboxylic acid and titanium tetraalkoxide react. Moreover, said suitable zirconium compound can be obtained by making the zirconium chelate compound synthesize | combined from said hydroxycarboxylic acid, zirconium tetraalkoxide, a zirconium carbonate, zirconium carbonate ammonium, etc. react.
Among the above titanium compounds and zirconium compounds, titanium compounds are preferable, and titanium lactate and titanium aminate are particularly preferable.
Said water-soluble transition metal compound (B) can be used not only independently but in mixture of 2 or more types as needed.

  The molar ratio of the vinyl alcohol unit of PVA to the transition metal atom in the transition metal compound (ratio of the number of vinyl alcohol units to the number of transition metal atoms) is 0.01-1. A range of 0 mole is used. By setting the transition metal atom to 0.01 mol or more with respect to 1 mol of the vinyl alcohol unit, problems of elastic strength, water permeability, and water resistance due to a decrease in the crosslink density between PVA and the transition metal atom can be avoided. Conversely, by setting the transition metal atom to 1.0 mol or less, it is possible to avoid problems such as the resulting gel loses flexibility and cracks occur when deformed. The molar ratio of the transition metal atom to 1 mol of the vinyl alcohol unit is more preferably in the range of 0.015 to 0.5 mol.

When the composition comprising (A), (B) and (C) as described above is allowed to stand for several minutes to several tens of hours in a temperature range of 1 to 40 ° C., a hydrogel rich in flexibility (elastic strength) and water shielding properties can be obtained. Since it is formed, workability is good. The thus obtained polyvinyl alcohol hydrogel of the present invention preferably has a penetration strength of 1 to 200 kPa in a penetration test of a metal rod. By setting it as 1 kPa or more, since the gel strength is high, excellent water shielding and durability can be obtained, and when it is set at 200 kPa or less, there is flexibility of the gel, so that it is possible to avoid cracks during deformation.
The penetration strength in the penetration test of a metal rod is 10 mm of a metal rod (stainless steel rod) having a diameter of 3.5 mm on a hydrogel obtained by holding the gel-forming composition in a container at 20 ° C. for 7 days. It is a numerical value (kPa) obtained by dividing the stress when the metal rod penetrates 10 mm into the hydrogel by the cross-sectional area of the metal rod in the test for penetration at a speed of / min.

Moreover, the obtained hydrogel is obtained by plugging the bottom of a glass tube having a length of 1 m or more, placing the gel-forming composition thereon so as to have a thickness of 2 cm, and maintaining at 20 ° C. for 7 days. After water was poured to a height of 100 cm on the obtained hydrogel having a thickness of 2 cm, the water level h (cm) after removing the stopper at the bottom of the glass tube and allowed to stand for 5 days was measured, and was calculated by the following formula (1). The water permeability is preferably 1 × 10 ⁻⁵ cm / sec or less.
Water permeability (cm / sec) = 2 × ln (100 / h) / (5 × 24 × 3600) (1)
(In the formula, ln represents a natural logarithm.)
By setting the water permeability coefficient to 1 × 10 ⁻⁵ cm / sec or less, high water content and good water impermeability (water impermeability) can be obtained. The water permeability coefficient of the polyvinyl alcohol hydrogel of the present invention is more preferably 1 × 10 ⁻⁶ cm / sec or less, and further preferably 1 × 10 ⁻⁷ cm / sec or less.

As the water resistance of the polyvinyl alcohol hydrogel of the present invention, the polyvinyl alcohol hydrogel is placed in a pH 2 aqueous solution at a bath ratio of 1: 100 (weight of polyvinyl alcohol hydrogel: weight of aqueous solution of pH 2) at 20 ° C. for 7 days. After dipping, the PVA weight retention (Wab) determined by the following formula (2) is preferably 70% or more.
Wab (% by weight) = 100− [10000 × (Wb) / (Wa)] (2)
(Wab represents the weight retention of PVA, Wa represents the initial solid content concentration (% by weight) of the hydrogel, and Wb represents the solid content concentration (% by weight) after immersion for 7 days at 20 ° C.)
By setting the weight retention of PVA to 70% or more, excellent water barrier properties are ensured for a long period in the acidic region.
Here, the water resistance test of the hydrogel body is performed according to the following procedure.
First, a part of the gel body is collected in a sample container while preventing moisture from evaporating, weighed, and further dried at 105 ° C. for 24 hours to measure the solid content concentration Wa (% by weight). On the other hand, test water adjusted to pH 2 and temperature 20 ° C. with hydrochloric acid or aqueous sodium hydroxide solution is facilitated. 10 g of the hydrogel is taken and 1000 g of the test water is added at a bath ratio of 1: 100. After capping the sample container, hold it at 20 ° C. for 7 days. Then, after pulverizing at 9000 rpm for 10 minutes using a mixer, the mixture is treated for 1 hour with light stirring at a temperature of 50 ± 3 ° C. and filtered.
The filtrate and a reference PVA solution with a known concentration are colored by adding an iodine solution at 20 ° C., and then the light transmittance is obtained with a colorimeter. A calibration curve in which the light transmittance is plotted on the horizontal axis and the concentration of PVA is plotted on the vertical axis, the PVA concentration Wb (% by weight) of the filtrate is obtained from the graph, the elution rate of PVA is obtained by the following formula, and the weight Find the retention rate.
PVA elution rate (% by weight) = 10000 × [(Wb) / (Wa)]
PVA weight retention (% by weight) = 100-PVA elution rate (% by weight)

  The polyvinyl alcohol-based hydrogel of the present invention is not limited to the above-mentioned (A), (B) and (C), but also includes various polymers for adjusting viscosity such as acrylates and celluloses, specific gravity adjusting agents, pigments and dyes. Various agents such as PVA plasticizers, stabilizers and inorganic fillers typified by glycols may be added and blended.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
First, the physical property measuring method of the polyvinyl alcohol-based hydrogel used in each example and comparative example is shown below.

(1) Metal bar penetration strength [Metal bar penetration compression test]
After preparing various hydrogel-forming compositions at 20 ° C., they are put in a glass beaker having a capacity of 200 ml and left standing at 20 ° C. for 7 days. A stainless steel metal rod having a diameter of 3.5 mm is inserted into the center of the hydrogel from the upper vertical direction at a rate of 10 mm / min using an autograph made by Shimadzu Corporation, and the stress at the time of 10 mm penetration is cut off from the metal rod. The value divided by the area is the penetration strength [kPa].

(2) Permeability coefficient [Permeability test]
A rubber stopper is installed at the bottom of a commercially available rigid PVC pipe (inner diameter 25 mm), and various hydrogel forming compositions are poured into a 9.8 cm ³ (height 2 cm) and left at 20 ° C. for 7 days to form a hydrogel in the pipe. . Thereafter, the rubber plug at the bottom is removed, and a hollow PVC tube having an outer diameter of 25 mm is inserted so that the hydrogel does not move. Water is poured from the top of the tube to the height of 100 cm from the top of the gel (volume is 490 cm ³ ). Next, 5 ml of white birch oil is added so that the water does not evaporate to form an oil film on the surface of the water. In this state, the water level (distance from the top of the gel to the water surface) is measured for 5 days, and this is defined as h [cm]. Permeability coefficient is calculated by the following formula of water level (precipitation method) permeability test.
Water permeability [cm / sec] = 2 × ln (100 / h) / (5 × 24 × 3600)
Note that ln represents a natural logarithm.

(3) PVA weight retention [water resistance test]
A part of the hydrogel is collected while preventing the transpiration of water, and is weighed. Further, the solid content concentration Wa (% by weight) is measured by drying at 105 ° C. for 24 hours. Separately, 10 g of the above hydrogel was sampled and test water having a pH of 2 and a temperature of 20 ° C. was added at a bath ratio of 1: 100. After covering the sample container, the sample container is left in a thermostat adjusted to 20 ° C. for 7 days. After being left standing, this is pulverized at 9000 rpm for 10 minutes using a commercial mixer (model: MX-151S manufactured by National), and then treated at a temperature of 50 ± 3 ° C. for 1 hour while being gently stirred by hand. The treated solution is filtered, cooled to 20 ° C., and an iodine solution is added to the filtrate to develop a color. Then, the light transmittance is obtained with a colorimeter. Similarly, the light transmittance of another level of known PVA solution was obtained in the same manner, and the above filtrate was prepared from a calibration curve in which the light transmittance was plotted on the horizontal axis and the PVA concentration (% by weight) was plotted on the vertical axis. The PVA concentration Wb (% by weight) is obtained, and the elution rate of PVA is obtained by the following formula.
PVA elution rate (% by weight) = 10000 × (Wb) / (Wa)
The PVA weight retention rate (% by weight) is (100-PVA elution rate).

(4) Gelation time (Hr)
Various chemical solutions are prepared to a total volume of 200 cm ³ , poured into a 300 ml poly beaker, stirred for about 30 seconds with a stir bar, and then allowed to stand. The change in viscosity of the chemical solution is appropriately measured with a B-type rotary viscometer, and the time when it exceeds 10,000 mPa · s is defined as the gel time (Hr).

Examples 1-4, Comparative Examples 1-4
A PVA resin having a vinyl alcohol unit of 99.8 mol% (manufactured by Kuraray Co., Ltd., Poval 117HC: degree of polymerization 1700) is poured into water so as to be 10% by weight, and left to swell for 24 hours, and then heated. PVA was completely dissolved by stirring and cooled to 20 ° C. to prepare an aqueous PVA solution. This PVA aqueous solution is diluted with water to each predetermined concentration (5% by mass), a cross-linking agent such as a water-soluble transition metal compound (organic titanium compound) is added in a predetermined amount shown in Table 1, and then both solutions are stirred. And mixed thoroughly. The prepared liquid thus obtained was poured into a polyethylene beaker, sealed and allowed to stand until the liquid lost its viscosity at 20 ° C., and then the product was taken out and the physical properties of the hydrogel were measured.

In Examples 1 and 2 and Comparative Examples 1 and 2, a PVA aqueous solution and an organic titanium compound (titanium lactate, manufactured by Matsumoto Pharmaceutical Co., Ltd., Olgatics TC-315, concentration 45% by mass) were mixed, and then 25 % Aqueous ammonia solution was added to adjust the pH to 8.
In Examples 3 to 4 and Comparative Example 3, an organotitanium compound (diisopropoxytitanium bistriethanolamate, manufactured by Matsumoto Pharmaceutical Co., Ltd., Olgatics TC-400, concentration 80% by mass) was previously added with water. The solution was diluted 4 times with the solution and added to the PVA aqueous solution.
In Comparative Example 4, a trimethylol melamine-based cross-linking agent (Sumitex Resin M-3 manufactured by Sumitomo Chemical Co., Ltd., concentration 80% by mass) was used instead of the organic titanium compound, and the pH was adjusted to 4 by adding lactic acid. did.
The addition amount of the crosslinking agent shown in Table 1 is an addition amount (parts by weight) of an organic titanium compound or the like with respect to 100 parts by weight of the PVA aqueous solution.
The measurement results are shown in Table 1 for the physical properties of the hydrogel in each Example and Comparative Example.

Claims (11)

Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A) :( B) between the vinyl alcohol unit (A) and the titanium atom contained in the component (B) is 1: 0.01 to 1.0,
4) The degree of polymerization of (A) is 500 or more,
Polyvinyl alcohol, characterized in that the hydrogel formed from the gel-forming composition is used for civil engineering materials, building materials, agricultural and fishery materials, water purification materials, refrigerant bodies during human body heat generation, artificial artificial bait or toys -Based hydrogel usage.   In a penetration test in which a metal rod having a diameter of 3.5 mm is penetrated at a speed of 10 mm / min onto a hydrogel obtained by holding the gel-forming composition at 20 ° C. for 7 days in a container, the stress at the time of 10 mm penetration is obtained. The method for using a polyvinyl alcohol-based hydrogel according to claim 1, wherein the penetration strength divided by the cross-sectional area of the metal rod is 1 to 200 kPa. The bottom of a glass tube having a length of 1 m or more is plugged, and a gel-forming composition is placed thereon so as to have a thickness of 2 cm. On a hydrogel having a thickness of 2 cm obtained by holding at 20 ° C. for 7 days. The water level h (cm) after removing water from the bottom of the glass tube and leaving it to stand for 5 days after measuring water up to a height of 100 cm is 1 × 10 ^−5. The method for using the polyvinyl alcohol-based hydrogel according to claim 1, which is cm / sec or less.
Water permeability (cm / sec) =
2 × ln (100 / h) / (5 × 24 × 3600) (1)
(In the formula, ln represents a natural logarithm.) Polyvinyl alcohol-based hydrogel was immersed in a pH 2 aqueous solution at a bath ratio of 1: 100 (weight of polyvinyl alcohol-based hydrogel: pH of aqueous solution of pH 2) for 7 days at 20 ° C., and then obtained by the following formula (2) The method for using a polyvinyl alcohol-based hydrogel according to claim 1, wherein the weight retention (Wab) of the alcohol (A) is 70% or more.
Wab (% by weight) = 100− [10000 × (Wb) / (Wa)] (2)
(Wab represents the weight retention of polyvinyl alcohol (A), Wa represents the initial solid content concentration (wt%) of the hydrogel, and Wb represents the solid content concentration (wt%) after immersion for 7 days at 20 ° C. ) Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A) :( B) between the vinyl alcohol unit (A) and the titanium atom contained in the component (B) is 1: 0.01 to 1.0,
4) The degree of polymerization of (A) is 500 or more,
The civil engineering material characterized by containing the composition for gel formation which is. Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A) :( B) between the vinyl alcohol unit (A) and the titanium atom contained in the component (B) is 1: 0.01 to 1.0,
4) The degree of polymerization of (A) is 500 or more,
The building material characterized by containing the composition for gel formation which is. Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A) :( B) between the vinyl alcohol unit (A) and the titanium atom contained in the component (B) is 1: 0.01 to 1.0,
4) The degree of polymerization of (A) is 500 or more,
An agricultural and fishery material comprising a gel forming composition. Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A) :( B) between the vinyl alcohol unit (A) and the titanium atom contained in the component (B) is 1: 0.01 to 1.0,
4) The degree of polymerization of (A) is 500 or more,
The water purification material characterized by containing the composition for gel formation which is. Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A) :( B) between the vinyl alcohol unit (A) and the titanium atom contained in the component (B) is 1: 0.01 to 1.0,
4) The degree of polymerization of (A) is 500 or more,
The refrigerant | coolant body at the time of human body heat_generation | fever characterized by containing the composition for gel formation which is. Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A) :( B) between the vinyl alcohol unit (A) and the titanium atom contained in the component (B) is 1: 0.01 to 1.0,
4) The degree of polymerization of (A) is 500 or more,
An artificial simulated bait characterized in that it contains a gel-forming composition. Polyvinyl alcohol (A), water-soluble organic titanium compound (B) and water (C) are the main constituents,
1) The water-soluble organic titanium compound (B) is a titanium compound containing an amino alcohol as one component of a chelate-type ligand,
2) The ratio of (A) to the total amount of (A), (B) and (C) is 0.5 to 10% by mass,
3) The molar ratio (A) :( B) between the vinyl alcohol unit (A) and the titanium atom contained in the component (B) is 1: 0.01 to 1.0,
4) The degree of polymerization of (A) is 500 or more,
A toy comprising a gel-forming composition as described above.