JP2000095875A - Production of polyurethane-pva hydrogel membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject membrane having an asymmetric structure in the direction of the membrane thickness, such as a membrane having a side largely exhibiting the property of a polyurethane or a membrane having a side largely exhibiting the property of a PVA hydrogel, and useful for artificial skins, etc., by subjecting a polyurethane raw material and a polyvinyl alcohol to their interfacial polymerization reaction on an interface between solvents. SOLUTION: This method for producing a polyurethane-PVA hydrogel membrane comprises subjecting (A) the solution of a polyurethane raw material (for example, hexamethylene diisocyanate) and (B) the aqueous solution of polyvinyl alcohol to an interfacial polymerization reaction on an interface between mutually incompatible solvents. The solution of the component B is preferably dropwisely added to the solution of the component A to form capsule- like membranes by the interfacial polymerization reaction. The inner liquid is preferably extracted from the insides of the obtained capsule-like membranes to form the hollow capsule-like membranes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyurethane-PVA hydrogel film useful for artificial skin and the like.

[0002]

2. Description of the Related Art Polyurethane has excellent physical properties, and its application to artificial skin materials and the like has been studied. On the other hand, polyvinyl alcohol (abbreviated as PVA as appropriate in this specification)
Hydrogels are superhydrophilic materials with low cell adhesion,
There is an advantage of having various bioadaptability.

[0003] Therefore, in order to obtain a film having the advantages of the polyurethane and the PVA hydrogel, blending these materials to form a film has been studied.

However, since the urethane prepolymer reacts with an aqueous solvent, there is a problem that it is difficult to form a film bonded to a hydrophilic gel such as PVA by the above-mentioned method.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention
An object of the present invention is to provide a method for producing a polyurethane-PVA hydrogel membrane capable of forming a membrane in which a polyurethane and a PVA hydrogel are bonded.

[0006]

In order to solve the above-mentioned problems, the present invention employs the following technical means. The method for producing a polyurethane-PVA hydrogel membrane of the present invention is characterized in that a membrane is formed by causing an interfacial polymerization reaction at an interface between incompatible solvents of a solution of a urethane raw material and an aqueous solution of PVA.

That is, in this production method, an interfacial polymerization reaction is caused at an interface between incompatible solvents of a solution of a urethane raw material and an aqueous solution of PVA. A PVA aqueous solution may be dropped into the urethane raw material solution to cause an interfacial polymerization reaction to form a capsule-like film. With this configuration, it is possible to obtain a capsule-like membrane having more polyurethane properties on the outside. Further, application to a gel capsule or the like is also possible. Extract the inner liquid from the formed capsule-like membrane,
You may make it obtain the capsule-shaped film | membrane which has a substantially hollow space | gap. By each of the above manufacturing methods, a polyurethane-PVA hydrogel membrane having an asymmetric structure in the film thickness direction can be manufactured.

[0008] When formed by blending the raw materials, only a homogeneous film can be obtained, which is not suitable for artificial skin materials and the like. However, according to the production method of the present invention, a film having a side having more polyurethane properties or PVA A film or the like having a side having more properties of the hydrogel can be obtained, and a polyurethane-PVA hydrogel film having an asymmetric structure in the film thickness direction can be obtained.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

Some polyurethane-based films using diisocyanate as a cross-linking agent have been studied as artificial skin materials, but the present inventors have studied polyurethane-based elastomers from different viewpoints (artificial muscle materials). ing.

By the way, diisocyanates are apt to be decomposed by reacting with water, and therefore are not generally used for aqueous reactions. However, it is considered that a film having an asymmetric structure can be formed by utilizing the polymer film formation at the liquid-liquid interface. Therefore, polyvinyl alcohol (PV
A) A hydrogel film was prepared by promoting the crosslinking of PVA using the interface between an aqueous solution and a hexane solution of isocyanate.

As shown in FIGS. 1 to 3, film formation at the interface of an incompatible solvent was used. A PVA-urethane hydrogel film was prepared by a urethanization reaction at the interface using PVA for the aqueous system and isocyanate or isocyanate-terminated urethane for the non-aqueous system. Asymmetry was introduced into the membrane structure by utilizing the reaction due to diffusion of active species at the interface.

[0013]

Next, the configuration of the present invention will be described more specifically. (Example 1) As shown in FIGS. 1 and 2, a hexane solution of hexamethylene diisocyanate (HDI) is gently superimposed on a 5% aqueous solution of polyvinyl alcohol (PVA), and a PVA-HDI film formed on the interface is formed. Was recovered. The reaction was performed at a room temperature of 20 ° C. and a reaction time of 24 hours. (Example 2) As shown in FIGS. 1 and 2, PVA 10%
A hexane solution of HDI was gently superimposed on the aqueous solution, and the PVA-HDI membrane generated at the interface was collected. The reaction was performed at a room temperature of 20 ° C. and a reaction time of 24 hours. Example 3 As shown in FIGS. 1 and 2, PVA 15%
A hexane solution of HDI was gently superimposed on the aqueous solution, and the PVA-HDI membrane generated at the interface was collected. The reaction was performed at a room temperature of 20 ° C. and a reaction time of 24 hours.

Each PVA-HDI membrane was sufficiently washed with water and then immersed in water and stored. The chemical structure of the surface was analyzed by near-infrared Raman spectrum. Then, PV
A- HDI membrane apparent HDI content (apparent HDI
I content (%) = IHDI / (IPVA + IHDI) ×
100) was as follows.

Concentration of PVA aqueous solution (wt%) ... 5 10 15 HDI content on PVA side of PVA-HDI membrane (%) ... 81.26 42.44 24.97 HDI content on HDI side of PVA-HDI membrane (%) ... 85.92 49.28 26.06 The Raman spectrum of the obtained gel film revealed that the PVA was crosslinked by urethane bonds and that the film had an asymmetric structure. That is, the composition was different between the hexane solution side and the PVA aqueous solution side.

As shown in the graph of FIG. 4, the film thickness tended to increase with an increase in the reaction time, and the tendency was larger when the PVA concentration was lower. As a result of changing the concentration of the used PVA aqueous solution, the film thickness became almost constant at 10% or more. Example 4 As shown in FIG. 3, a 10% aqueous solution of PVA was dispersed as droplets in a hexane solution of HDI using a syringe and encapsulated by a reaction at the droplet interface. After the reaction, the capsules were collected and washed with water to remove unreacted substances.

As a result, a capsule having a nearly hollow structure (not necessarily hollow, but having a sparse interior) could be obtained.

Meanwhile, from an aqueous solution having a high PVA concentration,
A gel film with a low HDI content was formed. This film formation method
It can be applied to the production of gel capsules.

[0019]

The present invention is configured as described above and has the following effects.

Since the interfacial polymerization reaction is carried out at the interface between the immiscible solvents of the urethane raw material solution and the aqueous solution of PVA, a polyurethane film capable of forming a film combining the polyurethane and the PVA hydrogel can be formed. A method for producing a PVA hydrogel membrane can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating Examples 1 to 3 of a method for producing a polyurethane-PVA hydrogel membrane of the present invention.

FIG. 2 is a sectional view illustrating the embodiment of FIG.

FIG. 3 is a perspective view illustrating Example 4 of the method for producing a polyurethane-PVA hydrogel membrane of the present invention.

FIG. 4 is a graph showing the relationship between the passage of time and the change in film thickness when the concentration of PVA is 10% and 15%.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoichi Amaike 6-5-6 Sakyo, Nara City, Nara Prefecture Nitayama Research Laboratories (72) Inventor Shin Suzuki 6-5-6 Sakyo, Nara City, Nara Prefecture Nitta Narayama R & D Co., Ltd. No. 203, 44-chome, Kanazawa-shi, Pref. 203 No. 203 F-term (reference) HC03 JA42 RA02

Claims (4)

[Claims] 1. A polyurethane comprising a film formed by an interfacial polymerization reaction at an interface between incompatible solvents of a solution of a urethane raw material and an aqueous solution of PVA.
A method for producing a PVA hydrogel membrane. 2. The method for producing a polyurethane-PVA hydrogel film according to claim 1, wherein an aqueous solution of PVA is dropped into the solution of the urethane raw material to cause an interfacial polymerization reaction to form a capsule-like film. 3. The method for producing a polyurethane-PVA hydrogel membrane according to claim 2, wherein an inner liquid is extracted from the formed capsule-like membrane to obtain a capsule-like membrane having substantially hollow voids. 4. A polyurethane-PVA hydrogel membrane having an asymmetric structure in the film thickness direction produced by the production method according to any one of claims 1 to 3.