JPH0436132B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a patch, especially a plaster (plaster).
Regarding the improvement of

Plastering agents use polymers such as natural rubber or synthetic rubber, which have a relatively low water content, as a base material, but the manufacturing method of plastering agents using natural rubber or rubber materials such as styrene and isobutylene is described in the literature ( For example, as is clear from "Pharmaceutical Engineering Handbook" edited by Masayasu Sugihara et al., 30th edition, page 228), there are processes such as primary kneading and secondary kneading, and in the process of spreading onto flannel, nonwoven fabric, plastic film, etc. (packing), solvents are used. or spread it using
Alternatively, methods such as heat-pressing and spreading are employed. As described above, the method for producing plaster is very complicated and requires a great deal of time and effort.

Therefore, the present inventors conducted extensive research to find an excellent base material for plaster that does not have the above-mentioned drawbacks, etc., and as a result found that ethylene-vinyl acetate copolymer resin met the purpose and completed the present invention.

Ethylene vinyl acetate copolymer resin (hereinafter referred to as EVA)
To make plaster based on
First, you can heat it to about 90 to 150℃ to melt the base, then maintain the temperature at about 40 to 130℃, add various additives, and mix. Not only is there no need for a kneading process, but it is also easy to mix. Since the base material is dissolved in the case of spreading, there is no need for a solvent, and there is no need for pressure bonding, and it is sufficient to simply apply it to a uniform thickness on the backing.

In other words, when making a patch using EVA, there is no need for complicated operations, so there is no need to worry about malfunctions, and process control is easy. It exhibits good viscoelasticity and has excellent adhesion to the skin.

EVA is a copolymer resin of ethylene and vinyl acetate, and is conventionally used as an adhesive for packaging, bookbinding, and woodworking, as a modifier for paraffin, wax, asphalt, etc., and as an adhesive for adhesive tapes or sheets. Although it is known that it can be used as a patch base, the present inventors discovered for the first time its use as a base for a patch.

When using EVA as the base for the patch of the present invention, the vinyl acetate content (saponification method) is 15 to 50 wt%.
Melt index (JIS: K-6760-1966)
Preferably, EVA is 30 to 500 g/10 minutes. As the vinyl acetate content increases, adhesion to the skin improves, and the melting point decreases, making it easier to manufacture, but on the other hand, the acetic acid odor becomes stronger and the adhesive becomes more sticky to the skin. Also, as the vinyl acetate content decreases, the crystallinity of EVA increases,
It becomes stiff and difficult to adhere to the skin.
Therefore, EVA with a saponification degree of about 15 to 50 wt% is preferable. Furthermore, when the melt index increases, the cohesive force decreases, making it easy to flow and making it difficult to spread, and at the same time, it becomes sticky and has a poor feel when used. On the other hand, as the melt index decreases, the cohesive force increases and adhesion to the skin deteriorates. Therefore 30-500
(g/10 minutes) is preferable.

Usually, when a specific medicinal ingredient is added to a patch, alcohols such as glycerin and propylene glycol, hydrocarbons such as liquid paraffin, petrolatum and squalane, olive oil and soybean oil are used as solvents to dissolve or disperse the ingredient. oils and fats,
Fatty acids such as lauric acid and myristic acid are possible, but hydrocarbons are preferred for the present invention. Alcohols, fats and oils, or fatty acids are the base
It is not compatible with EVA and is difficult to dissolve or disperse uniformly, so it cannot be used as it is and unless it is solubilized or emulsified, it will separate from EVA and cannot be used.

When the patch of the present invention does not have sufficient adhesion to the skin due to the influence of added ingredients, etc., an adhesive such as polybutene, polyisobutylene, terpene resin, or olefin resin can be added to EVA to freely improve the adhesion. It can be adjusted.

To improve the conformability of the patch to fabric during manufacturing or to the skin when using the patch (feeling of a tight fit or stiffness), plasticizers such as diocterphthalate, chlorinated paraffin, and nonyl phenyl ethers are added to EVA. Can be adjusted freely.

Examples are shown below, but the present invention is not limited to the examples. In the example, dl-camphor, -menthol, methyl salicylate, and peppermint oil, which are used as anti-inflammatory analgesics, were mixed at 21:24:
The oil was mixed at a ratio of 24:31 (weight ratio) and added as the main component, but drugs such as indomethacin, ketoprofen, diclofenac sodium, steroid hormones, nitroglycerin, and scopolamine were used, but were not limited to these anti-inflammatory analgesics. There is no problem even if it is added. Further, flannel, nonwoven fabric, plastic film such as vinyl chloride film, polyethylene film, etc. can be used as the packing, and the coating amount can be from 0.01 mm or more in thickness.

Example 1 Vinyl acetate content 45wt%, melt index
80 (g/10 min) EVA (product name: Evaflex)
Heat 98.5 parts of 45
It was applied onto cotton cloth to a thickness of about 1 mm and cooled to obtain a patch.

Example 2 90 parts of the same EVA as in Example 1 was heated to 130°C and melted, then cooled to 90 to 100°C and preheated to 90°C.
Add 8.5 parts of light liquid paraffin (Japanese Pharmacopoeia compliant product) warmed to ℃ and stir well to mix uniformly. Cool while stirring. Confirm that the temperature is below 90℃, and add 1.5 parts of the main component oil. was added to the mixture, and the mixture was coated on a cotton cloth to a thickness of about 1 mm while stirring, and cooled to obtain a patch.

Example 3 Vinyl acetate content 25wt%, melt index
400 (g/10 min) EVA (Evaflex 310) 60
After heating 1 part to 130℃ and melting it, add 38.5 parts of polyisobutylene and stir well until it is evenly mixed. The mixture was cooled while stirring, and after confirming that the temperature was below 90°C, 1.5 parts of the main component oil was added, and the mixture was coated on cotton cloth to a thickness of about 1 mm while stirring, and cooled to obtain a patch.

Example 4 After heating and melting 60 parts of the same EVA as in Example 3 to 130°C, 37 parts of polyisobutylene and 1.5 parts of polyoxyethylene nonyl phenyl ether were added and mixed well until uniform. After cooling with stirring and confirming that the temperature was below 90°C, 1.5 parts of the main component oil was added, and while stirring, the mixture was coated on cotton cloth to a thickness of about 1 mm and cooled to obtain a patch.

Example 5 After heating and melting 59 parts of the same EVA as in Example 1 to 130°C, polybutene (average molecular weight 2350) 10
Part, light liquid paraffin (Japanese Pharmacopoeia Union product) 10
15 parts of terpene resin and 4.5 parts of polyoxyethylene nonyl phenyl ether and stir to equalize. The mixture was cooled while stirring, and after confirming that the temperature was below 90°C, 1.5 parts of the main component oil was added, and the mixture was coated on cotton cloth to a thickness of about 1 mm while stirring, and cooled to obtain a patch.

All of the patches obtained above were compatible with cotton cloth and had excellent adhesion to the skin and stickiness.

Claims (1)

[Scope of Claims] 1. A patch characterized by using an ethylene vinyl acetate copolymer resin having a vinyl acetate content of 15 to 50 wt% and a melt index of 30 to 500 g/10 minutes. 2. The adhesive patch according to claim 1, which contains one or more hydrocarbons such as liquid paraffin or squalane.