JPH06128395A - Production of water-insoluble polysaccharide film - Google Patents

Abstract

PURPOSE:To provide the title production process whereby a biodegradable water-insoluble film can easily be obtained from a water-soluble polysaccharide compound and whereby a film having different properties can be obtained by changing the production conditions. CONSTITUTION:The production process comprises forming an aqueous solution of a water-soluble polysaccharide compound such as carboxymethylcellulose, casting this solution on a flat surface, and bringing it into contact with a solution of a water-soluble metal salt to effect ion exchange between them when it is in a semi-coagulated state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a water-insoluble polysaccharide polymer film having strength adjusted from a water-soluble polysaccharide polymer compound having biodegradability.

[0002]

2. Description of the Related Art Water-soluble polysaccharide-based natural polymer compounds such as carboxymethyl cellulose, hyaluronic acid, xanthan gum, duran gum, agarose, and carrageenan are biodegradable, and have recently attracted attention as materials that can be treated as waste by microorganisms. However, in order to form a film of this, for example, a water-soluble polymer compound is dissolved in a solvent to form a solution, and this solution is spread on a flat surface and then subjected to chemical means such as cross-linking to make it insoluble in water. However, since the film obtained without such chemical means is water-soluble and lacks strength, it cannot be put to practical use at all.

As one means for solving such a problem, the present inventors have prepared a hydrosol of a natural polysaccharide polymer by subjecting it to heat treatment under predetermined conditions. Although a method for obtaining a hydrogel having a desired strength has been proposed, this method cannot avoid obtaining a film-like product, and thus its use is inevitably limited.
Therefore, no practical method has hitherto been known for obtaining a water-insoluble polymer film having a required strength from a water-soluble polysaccharide polymer compound by physical means.

[0004]

INDUSTRIAL APPLICABILITY The present invention is industrially feasible for producing a water-insoluble polymer film having a strength that can withstand practical use, using a water-soluble polysaccharide polymer compound as a raw material. The purpose is to provide a method.

[0005]

Means for Solving the Problems The present inventors have conducted various studies on a method of producing a water-insoluble polymer film from a water-soluble polysaccharide polymer compound, and as a result, have obtained an aqueous solution of the water-soluble polysaccharide polymer compound. On a flat surface, the water-insoluble polymer film can be obtained by ion-exchange treatment while the flowed product is in a semi-solidified state, and at that time, the treatment time can be changed to change the treatment time. The inventors have found that the strength can be appropriately increased or decreased, and have completed the present invention based on this finding.

That is, according to the present invention, an aqueous solution of a water-soluble polysaccharide polymer compound is prepared, and the aqueous solution is spread on a flat surface, and then contacted with a water-soluble metal salt solution in a semi-solidified state for ion exchange. The present invention provides a method for producing a water-insoluble polysaccharide polymer film characterized by the above.

The water-soluble polysaccharide polymer compound used as a raw material in the method of the present invention includes carboxymethyl cellulose, hyaluronic acid, xanthan gum, duragan gum, agarose, carrageenan, alginic acid, ester of cellulose and divalent carboxylic acid, chitosan and the like. To be done. In the method of the present invention, these polymer compounds are usually added to
It is used as an aqueous solution having a concentration of 05 to 10.0% by weight.

The aqueous solution of the water-soluble polysaccharide polymer compound is spread on a flat surface such as a glass surface or a metal surface to form a film. Then, a semi-solidified state capable of retaining the shape of a film on a plane, for example, 30 to 7 of water in an aqueous solution.
When 0%, preferably around 50% is reached, contact is made with the metal salt.

Examples of the metal salt include water-soluble salts such as sodium, potassium, lithium, magnesium, calcium and aluminum, such as chloride, sulfate, nitrate, phosphate, acetate, citrate and succinate. Is used, but the metal is preferably divalent or trivalent.

These metal salts are used as a solution having a concentration of at least 1% by weight, preferably 5% by weight or more.
Water is usually used as the solvent in this case, but other solvents such as methanol, ethanol and mixtures thereof can also be used.

The contact between the semi-solidified film and the metal salt solution is carried out by immersing the former in the latter. The dipping time is in the range of 10 minutes to 24 hours, and the strength of the film obtained by changing this time can be adjusted according to the purpose of use.

The polymer film thus obtained has sufficient strength to withstand use and can be used as a packaging material, a substrate material or the like. Further, since this product has biodegradability, even if the used product is discarded as it is, it will not be naturally decomposed by microorganisms and cause environmental pollution.

[0013]

According to the present invention, a water-insoluble film having biodegradability can be easily produced from a water-soluble polysaccharide polymer compound. Also, by changing the manufacturing conditions, films having different physical properties can be obtained.

[0014]

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Examples 1 to 3 Carboxymethylcellulose powder was added to water at room temperature and dissolved to prepare an aqueous solution having a concentration of 1% by weight. Next, this aqueous solution is spread on a glass plate and left to stand for 12 hours under atmospheric conditions to form a semi-solidified film, and then the aqueous solution of sodium chloride having a concentration of 2% by weight is carried on the glass plate. It was immersed in the solution for 12 hours to obtain a water-insoluble film.

Further, the same procedure was repeated using an aqueous solution of sodium chloride or an aqueous solution of aluminum chloride in place of the above aqueous solution of sodium chloride to obtain a water-insoluble film. Table 1 shows the physical properties of these water-insoluble films.

[0017]

[Table 1]

As is clear from this table, the higher the electron valence of the metal in the metal salt, the higher the breaking stress and Young's modulus, but the smaller the breaking elongation.

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Claims (2)

[Claims] 1. A method of preparing an aqueous solution of a water-soluble polysaccharide polymer compound, spreading the aqueous solution on a flat surface, and then contacting it with a water-soluble metal salt solution in a semi-solidified state for ion exchange. A method for producing a water-insoluble polysaccharide polymer film. 2. The production method according to claim 1, wherein the water-soluble polysaccharide polymer compound is carboxymethyl cellulose.