JPS6244259A - Visible light curable medical gypsum - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The Japanese invention relates to a medical FRP cast that is cured by visible light.

Plaster casts are used in the medical treatment of human fractures, dislocations, etc., but overwhelmingly the casts used for this purpose are a combination of plaster and cotton cloth.Plaster casts are cheap and easy to construct. Although it has the advantage of being harmless and providing the necessary strength, it is slow to cure and requires a considerable thickness to obtain the required strength. It is too heavy for the patient, it takes too long to dry, the patient has to endure the coldness of the affected area during the drying period of 2-3 days due to the latent heat of vaporization of water, and there is almost no ventilation, so the affected area Currently, patients are forced to endure considerable pain such as rashes while wearing the cast.

In response to these drawbacks of plaster casts, some research has recently begun to develop casts made of polymers, especially plastics2.For example, in Europe, moisture-curing casts made of glass fiber or cotton cloth have been developed. Products impregnated with polyurethane resin are beginning to be used in some areas. This type of cast is commercially available sealed in a plastic film due to its moisture content, and in practical use, after opening, it is immersed in water to absorb water, and cured using the reaction between polyurethane resin and water. This is an FRP cast made of FRP as a binder.

This type of cast is effective in terms of light weight, breathability, etc., but it takes a considerable amount of time to harden (15-30 minutes), and it is said to have the drawbacks of being somewhat lacking in rigidity in terms of strength. .

On the other hand, some research is also underway to develop UV-curable acrylic resin formulations combined with glass fibers or other fibrous reinforcing materials to replace plaster casts. The reason for this is that the ultraviolet curing method has the advantages of being able to use a radical initiator easily, curing quickly, being easy to apply, and producing a cast with high strength.

However, when ultraviolet rays are used to treat children, the elderly, or people with hypersensitivity, adverse effects such as skin irritation and inflammation sometimes occur, which is considered to be two problems. In fact, there is a trend towards banning ultraviolet curing methods in the dental field.

Therefore, as a result of research into a photo-curable cast that uses visible light, which is harmless to the human body, instead of ultraviolet light, the present invention has found that the advantages of the ultraviolet-curable cast are retained. .

We have succeeded in developing a cast that is completely harmless to the human body. The details of the invention will be described below.

Well-known photocurable resins include unsaturated polyester resins, polyfunctional acrylic resins, acrylic-urethane resins, and epoxy acrylate resins. All of these undergo a crosslinking reaction in the presence of peroxide and become thermosetting resins. Recently, it has become known to carry out such a curing reaction using light in the presence of a photopolymerization initiator. However, most of these methods use high-energy ultraviolet light. With this method, the above-mentioned effect on the human body is a problem.In the present invention, we conducted research based on the idea that if the resin could be cured by a photopolymerization reaction even with visible light, it would be possible to create a cast that is harmless to the human body. As a result, thermosetting epoxy acrylate resin,
By using a photopolymerization initiator such as the one listed in the example that has the ability to harden easily with visible light, it is possible to create a binder for casts in a way that is no different from the ultraviolet curing method, and the strength of the resulting cast can be increased. was excellent.

It has been found that this type of resin system has high adhesion to fibrous reinforcing materials such as glass fibers, resulting in FRP casts with superior strength compared to examples using other polyfunctional acrylic resins.

The cast material made of the resin composition and the wA fibrous reinforcing material is stored under light shielding to ensure its shelf life until practical use. For this purpose, they are stored in light-tight plastic film bags or other suitable containers.

When treating a cast, the cast material is removed from the container, an appropriate amount is wrapped around the affected area of the patient through a suitable protective cloth, and visible light is irradiated. If the formulation is appropriate, 10-
The composition hardens in 60 seconds and has sufficient strength.

The cast of the present invention can obtain sufficient air permeability by adjusting the amount applied to the fibrous material, and can be made extremely lightweight and strong by selecting m-fiber as the reinforcing material. . Also, unlike plaster casts, it has the effect of completely eliminating the patient's discomfort until it dries.

Furthermore, since visible light is used during treatment, it can be said that there will be no harmful effects on the human body at all. The present invention will be explained in more detail below by giving examples.

Miju Tsuji - Epoxy acrylate (Epicote 828 acrylate)
) 100g and 4g of camphorquinone as a polymerization initiator.
12 g of benzyl dimethyl ketal and 5 g of dimethylaminoethyl methacrylate were added, and the composition was
A glass fiber cloth with a diameter of 0 mm and a length of 1000 mm was impregnated and stored in a black plastic bag.

A cotton protective cloth was wrapped around the affected area of the patient, and a cast material of the present composition taken out from the bag was wrapped in two layers on top of the cloth, a transparent plastic film was further wrapped on top of this, and light was irradiated from a visible light lamp. The cast completely hardened in 15 seconds. After this, remove the excess plastic film and the installation is complete. This material has sufficient strength and breathability.

The weight was less than one-tenth that of gypsum.

A similar experiment was carried out using a mixture of 75 g of epoxy acrylate in Example 1 and 25 g of trimethylol propane triacrylate. In this example as well, a practical cast could be formed.

A similar experiment was conducted by replacing Epicote 828 acrylate in Example 1 with glycidyl methacrylate resin. The obtained cast had excellent impact properties.

Experiments were conducted in which the fibrous reinforcing material of Example 1 was replaced with synthetic fibers or cotton cloth. Although the strength of the glass fibers could not be obtained, a cast that could be used for practical purposes was obtained.

Claims (1)

[Claims] 1. A radical initiator and an auxiliary agent having the function of curing with visible light are mixed into a crosslinked resin that cures by a radical reaction, and various fibrous reinforcing materials are impregnated with this kind of resin composition, Visible light-curable resin casts are used by irradiating light in a range that is harmless to the human body for a short period of time, such as wavelengths of 380-550 millimicrons, to harden and mold the resin into the desired shape. 2. The visible light-curable cast according to claim 1, wherein the crosslinked resin is an epoxy acrylate resin, a modified product thereof, or a mixture with another polyfunctional acrylic resin. 3. The photopolymerization initiator itself or in the presence of an auxiliary agent is one that functions as a radical initiator at a wavelength of 380 to 550 millimicrons, and of course may also exhibit an initiator function in the ultraviolet region. A visible light-curable cast according to claim 1, to which this material is added. 4. The visible light-curable cast according to claim 1, wherein the reinforcing material is made of glass fibers, synthetic fibers, cotton fibers, etc. woven into various shapes. 5. Visible light curing according to claim 1, in which a cast material made of a combination of a crosslinked resin composition and various reinforcing materials is packaged in a bag-like material with light-blocking ability to provide preservability. mold cast.