JPH0524807B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing coated products by wet molding and coagulating an aqueous suspension of a hydrophilic polymeric material using a semipermeable mold. .

BACKGROUND OF THE INVENTION The wet process of producing coated products from hydrophilic (or water-soluble) polymeric materials involves passing an aqueous suspension or solution of the polymeric material or a mixture thereof through a nozzle into a tubular, thin or sheet shape. Coated products were manufactured by extruding into a coagulation bath, crosslinking, washing with water, and drying.

In addition, a method has also been proposed in which a polymer material is electrodeposited onto the electrode and molded by using an electrode with an appropriate shape and immersing the electrode in a water-washed suspension of the polymer material and then applying electricity. ing.

Problems to be Solved by the Invention In the conventional extrusion method for manufacturing polymeric material coated products, the stock solution is extruded through a nozzle into a coagulation bath. It was also difficult to mold.

Electrodeposition requires complicated equipment, and there is a risk of electric shock because it involves electricity. Furthermore, products manufactured by electrodeposition have the disadvantage that defects (pinholes and fissures) occur due to the action of air bubbles generated on the electrode during electrodeposition.

The present invention aims to improve the above-mentioned drawbacks and provide a method suitable for molding bag-shaped polymeric material products by a wet method.

Means for Solving the Problems The present invention uses an aqueous solution, an aqueous suspension, or a mixture of both (hereinafter simply referred to as an aqueous suspension) of a hydrophilic polymer material (including a water-soluble polymer material) as a stock solution. and a method for manufacturing a coated product using the present invention. A mold made of a semi-permeable material is used as the mold.

The method of the present invention involves pre-impregnating the wall of a mold made of a semipermeable material with a coagulant suitable for coagulating the raw polymeric material, and then bringing the stock solution into contact with this wall surface, so that the coagulant is absorbed into the stock solution near the wall surface. The polymer material in the undiluted solution is diffused into the liquid and solidified along the wall surface to form a film. Another embodiment is to use a container-shaped mold, inject the stock solution into the mold, and immerse this mold in a coagulation bath, so that the coagulation liquid passes through the wall of the mold and near the inner wall surface of the container-shaped mold. The polymer material can be solidified along the wall surface by diffusing into the stock solution.

After the polymer material is formed into a film along the wall of the mold by either method, the unsolidified stock solution is removed (in the case of a container-shaped mold, the stock solution is poured out), and then it is solidified on the side opposite to the mold wall. By bringing the coagulant into contact with the coating (in the case of the container-shaped type, the coagulating liquid is injected after the raw solution has flowed out), the polymeric material coating can be completely coagulated.

Formation of the Coating At any point during the solidification operation, after the stock solution is injected into the mold, after the stock solution has been drained and the solidified film is molded against the inner wall of the mold, or after the film is formed to complete solidification. It is also possible to concentrate the formed coagulated film by applying pressure inside the container-shaped mold when the coagulating liquid is poured into the mold. Further, it is also possible to further concentrate the coagulating liquid by leaving it for a while after discharging the coagulating liquid and evaporating a part of the coagulating liquid from the outer surface of the mold (the wall surface of the mold opposite to the pattern on which the film is formed). By carrying out this concentration operation, the strength of the coagulated film increases, making subsequent processing easier.

The molded and solidified film is peeled off from the mold wall and taken out, and if necessary crosslinked, washed with water, and dried. The coating can be easily removed by reducing the pressure inside the container during peeling.
Incidentally, the crosslinking treatment can also be carried out simultaneously by adding a crosslinking agent to the coagulation solution.

Semipermeable materials for molds used in the present invention include porous materials such as unglazed ceramics, glass filters, porous sintered metals, sintered wire mesh, cellulose fiber paper, poly(tetrafluoroethylene) paper, and silica fiber paper. It is also semipermeable and has the necessary thickness and strength as a mold.

Hydrophilic polymer materials used as raw materials in the present invention include casein, gelatin, collagen, albumin, fibroin, keratin, fibrin,
Proteins such as gluten; cellulose, starch, agar,
Natural polymeric materials such as carrageenan, konjac mannan, sodium alginate, sodium carboxymethylcellulose, methylcellulose, cellulose sulfate, chondroitin sulfate, polysaccharides such as hyaluronic acid; and polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyglutamic acid , polyethyleneimine, and other anionic, cationic, nonionic, and zwitterionic polymeric materials can be used. Furthermore, two or more of these polymeric materials can be used in combination.

The above-mentioned polymeric material can be used either by dissolving in water to form an aqueous solution, mechanically pulverizing it and dispersing it in water to form an aqueous dispersion, or as a mixture of both.
The term aqueous suspension herein is intended to include all of the above conditions.

Coagulants used in the present invention include salts such as common salt, mirabilite, ammonium sulfate, ammonium chloride, ammonium acetate, calcium chloride, and magnesium chloride; ethanol;
Organic substances that have a dehydrating effect such as methanol and acetone, anionic activators such as carboxylic acid type, sulfuric acid ester type, and sulfonic acid type, cationic activators such as alkylamine salt type, alkyl quaternary ammonium salt, and alkyl quaternary pyridinium salt. Contains ionic surfactants. Furthermore, two or more types of the above-mentioned coagulants can be used in combination.

The method of the present invention is achieved by appropriately changing the shape of the mold and by changing the molding material.
Products of various shapes can be obtained. For example, bag-shaped food casings (for example, packaging for meat such as ham, sausage, smoked salmon, and fish roe such as cod roe) can be manufactured using an edible hydrophilic polymer material.
In addition, using polymeric materials that are non-toxic to the human body,
Medical supplies such as gloves, Y-shaped tubes, T-shaped tubes, and cross tubes, and daily necessities such as nursing nipples and condoms can also be manufactured.

By locally changing the wall thickness of the mold made of the semipermeable material of the present invention, the amount of coagulant per unit area to be impregnated or permeated can be changed, and solidification molding can be achieved in areas where the amount of impregnation or permeation is large. The film thickness of the polymer material used can be increased. In addition, by changing the shape of the mold to various container shapes, dish-shaped tray shapes, plate shapes, etc., molded products can be obtained according to the wall surfaces thereof.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A 1M aqueous solution of calcium chloride was poured into a flask-shaped unglazed container and allowed to seep into the inside of the unglazed container wall, then the calcium chloride solution was taken out, and then a 2% concentration sodium alginate aqueous solution was poured in and after being left for 2 minutes, the sodium alginate was dissolved. The aqueous solution was drained. An alginic acid film was formed along the inner wall of the container. An aqueous calcium chloride solution was again added to the container to complete coagulation of the alginic acid coating. When the coagulated film was taken out, washed with water, and dried, a uniform, transparent bag-shaped film with a thickness of 20 microns was obtained.

Example 2 Concentration 1 in a test tube-shaped container made of tetrafluoroethylene
%, pH 3.0, the container was immersed up to the neck of the saturated saline solution bath, and left for 5 minutes. When the collagen solution was poured out, a collagen film was formed on the inner wall of the container. Saline was injected into the container to completely coagulate the collagen coating. Remove the membrane, neutralize it, wash it with water, and reduce the water column pressure to 20
When dried while blowing air of mm, the thickness was 18 mm.
A micron bag-shaped collagen membrane was obtained.

Claims (1)

[Claims] 1 Using molds made of semipermeable materials of various shapes,
In this method of manufacturing a coated product of a hydrophilic polymer material along the wall surface of this type, (a) the wall of the semipermeable material is impregnated with a coagulant in advance, and the wall surface is coated with a hydrophilic polymer material. contacting an aqueous suspension of molecular materials or
or (b) an aqueous suspension of a hydrophilic polymeric material is placed in a mold of the semipermeable material, and the mold is immersed in a coagulation bath to coagulate the polymeric material along the wall surface. A method for producing a hydrophilic polymer material film characterized by forming a film.