JPS6151017A - Water-containing elastomer and its production - Google Patents

Abstract

PURPOSE:To obtain a water-containing elastomer excellent in strength and shape stability and useful for enzyme-immobilizing membranes, ionic electrode membranes, etc., by polymerizing an acylamide-based monomer in the presence of imogolite. CONSTITUTION:The desired water-containing elastomer is obtained by homogeneously dispersing imogolite in an acrylamide-based monomer and polymerizing the monomer. Said imogolite may be nautral or synthetic one. Its iron component, organic matter, free aluminum, silicic acid, etc., are removed by chemical purification. The viscosity of its dispersion is preferably 5.0 or above when measured in an aqueous acetic acid solution of pH of 3.5 as the dispersing medium at a temperature of 30 deg.C and a concentration of 0.2wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a water-containing elastomer comprising a hydrophilic cloth Ia polymer containing imogolite acrylamide as a main component.

(○) Conventional technology and problems Polyacrylamide is a water-containing polymer.

There are synthetic polymers such as polyacrylic acid, polyvinyl alcohol, poly2-hydroxyethyl acrylate, and polyvinylpyrrolidone, and natural polymers such as agar and gelatin.
Thickener, water retention agent 1 surface treatment agent.

It is used in the fields of medicine, agrochemicals, cosmetics, food, etc. as part 11111A. However, until now, no elastomer has been obtained that has a high water retention rate and excellent shape stability and strength.

(c) Means for Solving the Problems The present inventors focused on the fact that imogolite is a rigid, non-defining polymer with good water dispersibility, and developed a hydrous elastomer with excellent shape stability, strength, and moldability. As a result of intensive research on how to obtain imogolite, we discovered that by uniformly dispersing imogolite in a monomer whose main component is acrylamide, and polymerizing it, we can create a product with high water retention, excellent morphological stability, strength, and moldability. The present invention was based on the discovery that elastomers can be easily obtained industrially.

That is, the present invention provides a hydrophilic polymer containing imogolite and acrylamide as a main component.
- It's a mer.

Imogolite is a hollow fiber □-shaped aluminosilicate polymer with an outer diameter of about 20 mm and an inner diameter of about 7 A, found naturally in volcanic ash soil and weathered pumice layers, and its chemical composition is approximately 3. 203 ・2~3H20. Such imogolite can be produced by a known method, for example, by dispersing soil containing imogolite in water, collecting floating matter mainly composed of imogolite, and refining this floating matter in accordance with the method of the Clay Handbook (edited by the Clay Society of Japan). It can be obtained by That is, the iron content was removed by the JacksOn method (sodium citrate-sodium hydrosulfide-sodium bicarbonate extraction method), and organic matter contained as impurities was decomposed and removed by heating with H20□ water, and 2% N
82 Boiling with CO3 to remove free aluminum and silicic acid yields a gel-like purified product of imogolite.

Alternatively, this imogolite may be dispersed in an acidic aqueous solution such as hydrochloric acid, and then precipitated and gelled with an alkali or common salt to form a more purified gel-like imogolite.

The imogolite used in the present invention may be synthesized. Synthesis methods include a method in which imogolite is synthesized by heating refluxing aluminum hydroxide and a silicate complex in an acidic aqueous solution (Japanese Patent Application Laid-Open No. 124199/1982), and a method in which aluminum alkoxide and tetraalkyl silicate are hydrated in an acid. A method is known in which imogolite is synthesized by heating and refluxing decomposed aluminum hydroxide silica salt in an acidic aqueous solution (Japanese Unexamined Patent Publication No. 10498/1983). ,
The natural imogolite or synthetic imogolite obtained by purification in this way is a mixture of various degrees of m, and the dispersion has a viscosity. (77S11/C) Ha, pH=3
．． Using an acetic acid aqueous solution of No. 5 as a dispersion solvent, at 30°C and 0.2
It is less than 5.0 when measured in weight % fJ degrees. The above-mentioned imogolite may be used in the present invention, but in order to obtain a high-quality elastomer, it is preferable that the dispersion liquid viscosity (ηsp/c) be 5.0 or more.

Such an imogolite dispersion can be produced using the method described in JP-A-58-45108. As the dispersion medium, water and polar organic solvents such as formamide, N-methylformamide and dimethyl sulfoxide can be used, but acidic water, particularly water having a pH of 3 to 5, is preferred.

In the present invention, the hydrophilic polymer containing acrylamide as a main component means polyacrylamide or a hydrophilic copolymer of acrylamide and other monomers.

These can be obtained by known methods.

The hydrous elastomer of the present invention comprises the imogolite,
For example, it can be obtained by sufficiently stirring and mixing a dispersion liquid and an aqueous solution of a hydrophilic polymer, for example, by an appropriate method, but it is preferable to polymerize acrylamide in the presence of imogolite. This is a method of copolymerizing other vinyl monomers. For example, after adding the imogolite solution and sufficiently dispersing it, an initiator can be added and polymerization can be carried out. Polymerization is conventionally known radical polymerization.

This can be carried out by photopolymerization, radiation polymerization, etc.

The concentration of acrylamide is preferably 5 to 30%, and the amount of imogolite added is preferably in the range of 0.02 to 5%. Examples of monomers to be copolymerized with acrylamide include acrylic acid, methacrylic acid, 2- and droxyethyl acrylate, N-vinyl-2-pyrrolidone, and acrolein. As long as the resulting copolymer is hydrophilic, a hydrophobic monomer may be used, and a crosslinking agent such as methylenebisacrylamide may be used in combination. As a polymerization initiator,
Over 1iI! t'FIi ammonium, per[1-sodium, riboflavin, etc., and tetramethylene diamine, β-dimethylaminopropionitrile, etc. can also be added as a polymerization accelerator. Depending on the purpose of use, the mixture of imogolite and monomer may be poured into a film-like, plate-like, or other formwork, and then polymerized in the presence of heat, light, or radiation.

B) Effects of the Invention The hydrous elastomer of the present invention, which is composed of imogolite and a hydrophilic polymer mainly composed of acrylamide, has the following properties:
It has superior strength and morphological stability compared to conventional acrylamide gels, and can be formed into films, fine particles, etc. for use in immobilized enzyme membranes, ion electrode membranes, electrolytic membranes, and electrophoretic analysis. gel, liquid chromatography gel,
It can be used as a catalyst support.

(→ Examples The present invention will be explained in detail with reference to Examples below.

The viscosity of the imogolite dispersion (ηSp/C) was measured using an acetic acid aqueous solution at pH-3.5 as the dispersion solvent.
It was carried out using an Ubbelohde viscometer at 0° C. and at a concentration of approximately 0.2 fJff 1%. The dispersion liquid was subjected to ultrasonic treatment for 30 minutes using a Plansonic ultrasonic cleaner model 220 before being subjected to measurement. For accurate measurement concentration, collect the dispersion liquid in a magnetic crucible of 15 precepts, evaporate water at 50℃,
The viscosity was determined from 1ffi of the residue baked at 500°C for 2 hours in an electric furnace, and the measured viscosity was converted to ηsp/c at a concentration of 0.2m %.

All percentages in the examples are mff1%.

Example 1゜Water was added to the collected weathered pumice layer containing a lot of imogolite, and after stirring thoroughly, the water suspended matter was filtered through a sieve (10-201
11eSh). After removing impurities such as leaves, a 7% imogotate gel was obtained on a wet basis. The separated imogolite gel was prepared using the conventionally known method 1711,
That is, 400 parts of imogolite gel and 8 parts of sodium citrate.
0 parts, 32 parts of Na HCO and 500 parts of ion-exchanged water were added and dissolved by heating in a hot bath at 80°C, 5 parts of NazCOz powder was added and stirred, kept for 15 minutes, filtered with suction to remove iron, and then Add 2% NazCOa and boil for 5 minutes to remove A41. It was treated with silicic acid and then heated with 30% H202 to remove organic substances contained as impurities and purify it.

The purified imogolite gel thus obtained was subjected to Soxhlet extraction with an acetic acid aqueous solution (1) 83.5) for 100 hours. A fine powder precipitate (imogolite with a relatively low degree of polymerization) containing a small amount of iron was observed in the extract. The imogolite gel of the Soxhlet extraction residue was dissolved in an acetic acid aqueous solution (1) H3, 5) at an output of 40 W using a Kubota ultrasonic dispersion device 200M type (excavation frequency 9KH2).
Dispersed for minutes.

The undispersed material was centrifuged at high speed (14,000 rpm,
30 minutes), and the supernatant liquid was concentrated using a 0-Tary evaporator to obtain a dispersion liquid having a concentration of 0.83%.

p) (Dispersion viscosity (ηs
p/c) was 6.4 (0.2%, 30°C).

50 parts of the imogolite dispersion thus obtained and an acrylamide preparation solution (acrylamide 16.7% ININ'-
Aqueous solution containing 0.45% methylenebisacrylamide)
50 parts were stirred and mixed thoroughly, N, N, N', N
'-tetramethylenediamine 0.25 parts and 0.75 parts
% ammonium persulfate aqueous solution was added and mixed. The mixture was degassed under reduced pressure with stirring, and then poured between two glass plates with a gap of 0.5 layer width, taking care not to introduce air bubbles, and left at air temperature for 5 hours to allow cross-linking polymerization. Ta. The physical properties of the obtained elastomer are as follows: thickness: 0.42 m, strength: 60 g/-
1 elongation was 97%. Moreover, the refractive index was 1.355 at 20°C.

For comparison, a similar experiment was conducted with 50 parts of water added instead of the imogolite dispersion, and the resulting film was brittle and easily broken, so the strength was measured.

I couldn't do it. Also, 2% of Laponite XLG, which is a gel-type synthetic mica. A similar experiment was conducted using an aqueous solution instead of the imogolite dispersion, and as a result, the elasticity of the molded product was somewhat improved compared to the case of water, but the molded product was brittle and no improvement in strength was observed.

Example 2゜When the imogolite dispersion of Example 1 is left for 10 days, 2
It separates into layers, while the upper layer is slightly milky.
The lower layer was colorless and transparent. The concentration of imogolite in the lower layer of the dispersion was 0.88%, and the viscosity of the dispersion (ηSO/C) was 9.
It was 5.

50 parts of the lower layer liquid of this imogolite dispersion and 50 parts of the 7-crylamide preparation were stirred and mixed thoroughly, -N, N,
0.13 parts of N'.N'-tetramethylenediamine and 5 parts of a 0.75% ammonium persulfate aqueous solution were added and mixed. After degassing while stirring under reduced pressure, the mixture was
．． The mixture was injected between two glass plates having a gap of 0ffi width so as not to introduce air bubbles, and left overnight at air temperature for cross-linking polymerization. The resulting elastomer has a thickness of 1.05a+m and a strength of 6.
49/mtfr, and elongation was 133%.

Example 3 To 50 parts of an acrylamide preparation solution, 0.1 part of an ultraviolet initiator benzyl dimethyl ketal and N, N, N' were added.

After adding 20 parts of an N-methylformamide solution in which 0.25 parts of N'-tetramethylenediamine was dissolved and mixing well, the imogolite dispersion lower layer liquid 5 used in Example 2 was added.
0 parts were added and mixed. After degassing under reduced pressure and stirring, the mixed solution was injected between two glass plates having a gap of 0.5 part width, being careful not to introduce air bubbles. and,
PjA polymerization was carried out for 3 hours under ultraviolet irradiation.

The physical properties of the obtained elastomer were a thickness of 0.501 MI.

The strength was 49 g/IIIi and the elongation was 225%.

For comparison, when water was added instead of the imogolite dispersion and molded in the same manner, the resulting molded product was weak and would break, so it was not possible to measure the strength.

Experimental Example 4 After adding 5 parts of 2-hydroxyethyl methacrylate to 50 parts of the acrylamide preparation solution and mixing well, Example 1
Add 30 parts of the imogolite dispersion used in , and while stirring, add 0.13 parts of N,N,N',N'-tetramethylenediamine and 5 parts of 0.75% ammonium persulfate aqueous solution.
part and mixed well.

After degassing under reduced pressure, the mixture was left to stand overnight at V temperature to carry out crosslinking polymerization. The molded product was elastic and an elastomer with strong tensile strength was obtained. Similar elastomers were also obtained when 2-hydroxyethyl acrylate or N-vinyl-2-pyrrolidone was used instead of 2-hydroxyethyl methacrylate.

For comparison, an experiment was conducted on the same sphere using water instead of the imogolite dispersion, and the result was that the molded product was brittle (and easily fractured when crushed).

Experimental Example 5 After stirring and thoroughly mixing 50 parts of the lower layer liquid of the imogolite dispersion used in Experimental Example 2 and 50 parts of the acrylamide preparation liquid, N,N,N',N'-tetramethylenediamine 0
．． 13 parts and riboflavin solution (0.1 m9/it>
5 parts were added and mixed. After degassing the mixture under reduced pressure, the mixture was injected between two glass plates having a gap of 0.3 part width so as not to introduce air bubbles, and cross-linked and polymerized by ultraviolet irradiation. The obtained film-like elastomer exhibited excellent morphological stability. On the other hand, a reaction product similarly polymerized using water instead of the imogolite dispersion had poor morphological stability and was easily broken unless handled with care.

that's all

Claims (1)

[Claims] 1. A water-containing elastomer comprising imogolite and a hydrophilic organic polymer containing acrylamide as a main component. 2. A method for producing a water-containing elastomer, which comprises polymerizing a monomer containing acrylamide as a main component in the presence of imogolite.