JPS6245678A - Self-adhesive - Google Patents

Abstract

PURPOSE:To obtain a self-adhesive free from contact dermatitis and skin irritation and suitable for medical tapes etc., by blending a low-molecular, water-soluble gelatin and/or decomposed gelatin having a molecular weight higher than the former gelatin with a polyhydric alcohol and a particular crosslinking agent. CONSTITUTION:A low-molecular, water-soluble gelatin obtd. by hydrolyzing collagen and having a molecular weight of about 5,000-10,000 and/or a decomposition gelatin having a molecular weight of about 30,000-50,000 and obtd. by decomposing collagen or gelatin with an acid or alkali are mixed with a plasticizer comprised of a polyhydric alcohol (e.g., glycerin or polyglycerin), a crosslinking agent and a grafting agent comprised of mono- or polyhydric alcohol contg. alkylene oxide segment and/or glycidyl ether of mono- or polyhydric alcohol (e.g., polyethylene glycol diglycidyl ether), and water.

Description

[Detailed Description of the Invention] The present invention relates to an adhesive that uses gelatin, which is a biologically derived substance, and is particularly suitable for use as a medical adhesive for bandages, surgical tapes, transdermal drugs, etc. This invention relates to adhesives.

Follow-me! Conventionally, acrylic adhesives and rubber adhesives have been used as medical adhesives. Common acrylic adhesives include 2-ethylhexyl acrylate,
There are products that combine ingredients such as butyl acrylate with ingredients such as vinyl acetate and methyl methacrylate.
Although such adhesives have excellent heat resistance and durability, they have the disadvantage that the tank capacity at low temperatures is rather low. On the other hand, common rubber-based adhesives include natural rubber or synthetic rubber as the main component, to which an appropriate amount of rosin, rosin ester, or synthetic hydrocarbon resin is added as a tackifier. Adhesives have a wide range of compounding tolerance, making it easy to control their properties, but on the other hand, they are expensive. It has the drawbacks of poor n characteristics and poor durability. Moreover, all of these adhesives have a major drawback in that they are highly irritating to the skin and often cause rashes and skin irritation.

On the other hand, as seen in Japanese Patent Application No. 59-2365, an adhesive containing gelatin as a main component and a plasticizer and a gelling inhibitor has been proposed, but such an adhesive has a temperature range from room temperature to around body temperature. There is a significant change in adhesive properties between temperatures of 37°C to 37°C, and there are problems in terms of adhesive residue on the skin and stringiness, especially under high temperature and humidity conditions near body temperature. Moreover, if the adhesive is formulated to prevent the adhesive from remaining on the skin in hot and humid conditions, it will not have enough tackiness at room temperature, so it will take time for the tackiness to reactivate when applied. There is an inconvenience that it must be held in close contact with the skin for a long time. In addition, the large amounts of external gelling agents such as CaCl and urea often cause rashes and dermatitis, making them unsatisfactory as medical adhesives.

33Fu1inch The present invention was made in view of the above circumstances, and its purpose is to cause almost no skin irritation or rash, to cause little physical irritation to the skin during peeling, and to be able to remove skin from room temperature to near body temperature. The purpose of the present invention is to provide a highly safe medical adhesive that has the same adhesive properties up to 20°C to 37°C.

In order to achieve the above object, the adhesive of the present invention contains water-soluble gelatin with a low molecular weight and/or decomposed gelatin with a higher molecular weight, an epoxy compound having a polyhydric alcohol and an alkylene oxide segment, and water. The gist is that it consists of the following ingredients.

Specifically, the adhesive of the present invention is made of 100% low molecular weight water-soluble gelatin with molecules ff of about 15,000 to 10,000, which is a collagen hydrolyzate, or collagen or gelatin decomposed with acid, alkali, proteolytic enzyme, etc. The obtained high molecular weight acid-decomposed gelatin with a molecular weight of about 30,000 to 50,000 is mixed with the above low molecular weight water-soluble gelatin at a ratio of 10 to 90%, and the mixture is mixed with water in an amount of 1 to 4 times the amount of total gelatin. 20 to 300 parts by weight of polyhydric alcohol as a plasticizer and 1 to 50 parts by weight of an epoxy compound having an alkylene oxide segment as a crosslinking agent or grafting agent were added and mixed at 60°C.
After reacting for 1 to 20 hours, it was coated on a support, and then dried and moistened.

Here, if high-molecular-weight gelatin is used alone as gelatin, the desired adhesive cannot be obtained because it has weak adhesiveness near body temperature and does not function as an adhesive. Therefore, when it comes to gelatin, one with a low molecular weight is used alone, or one with a high molecular weight and one with a low molecular weight is used as a mixture, but when comparing the two, the latter has almost constant adhesive properties near body temperature. It is desirable because it has the advantage of being able to adjust the adhesive.

In addition, when using low molecular weight water-soluble gelatin with a molecular weight of about 5,000 to 10,000 as described above, it has the advantage of exhibiting adhesive properties at room temperature.
Molecular weight 30,000-5 as high molecular weight decomposed gelatin
When using one having a molecular weight of about 0,000, it has the advantage that adhesive properties are developed at about 37°C.

In addition, if the amount of polyhydric alcohol as a plasticizer is less than 20 parts by weight, or if the amount of epoxy compound having an alkylene oxide segment as a crosslinking agent is less than 1 part by weight, the tackiness will be weak at room temperature and will be sticky at around 37°C. This should be avoided as it will cause the agent to remain on the skin and cause stringiness.On the other hand, if the crosslinking agent is more than about 50 parts by weight, the adhesive strength will be weak even at room temperature or around 37°C, so this should also be avoided. be.

Furthermore, if a crosslinking agent or grafting agent with long alkylene oxide segments is used, a soft rubber-like adhesive can be obtained, whereas if a short segment is used, a hard-feeling adhesive can be obtained.

As the polyhydric alcohol serving as a plasticizer, glycerin and polyglycerin, which is a 3 to 12 combination of glycerin, are suitable. Furthermore, fatty acid esters of polyglycerin are recognized as food additives, and like glycerin, they are harmless and can be used in combination. These plasticizers not only plasticize gelatin, but also have water retention properties and play a major role in developing adhesive properties of gelatin.

The epoxy compound used as a crosslinking agent or grafting agent is a mono- or polyepoxy compound, and specifically, ethylene glycol, polyethylene glycol diglycidyl ether (degree of concentration 1 to 22), propylene glycol, polypropylene glycol diglycidyl ether (polymerized degrees 1 to 11), neobentyl glycol diglycidyl ether, 1.6 hexanediol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, 0-phthalic acid diglycidyl ether, glycerol polyglycidyl ether, trimethylol propane polyglycidyl ether , diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, allyl glycidyl ether.

2-Ethyl hequinyl glycidyl ether phenyl glycidyl ether, phenol (EO) glycidyl ether, p-terjarybuterphenyl glycidyl ether, dibromophenyl glycidyl, lauryl alcohol (
EO) Glycidyl ether, glycidyl ether of CA-C alcohol mixture, etc., and especially glycerol polyglycidyl ether is preferably blended in the above formulation.

As described above, these epoxy compounds have good affinity with gelatin, water, and plasticizers, and have almost no irritation to the skin If.

The above adhesive uses low molecular weight water-soluble gelatin and/or high molecular weight decomposed gelatin, so
There is no need to add gelation inhibitors that are irritating to the skin.
In addition, by using a crosslinking agent or a grafting agent, a three-dimensional structure is formed due to intermolecular interactions such as strong crosslinking or weak hydrogen bonds between gelatin molecules, and the grafting of alkylene oxide chains has a plasticizing effect on gelatin. This promotes the adhesion properties of the adhesive, which is unaffected by temperature and humidity.

The amount of water after humidity conditioning is 10% to 100%, preferably 20% to 70%.

Next Ju! L An embodiment of the present invention will be described below.

[1] Blend> Low molecular weight water-soluble gelatin 80 parts by weight High molecular weight acid-decomposed gelatin 20 ~ water
200 polyglycerin
300 Crosslinking agent (glycerol digly 15 ~
(Dyle ether and glycerol triglycidyl ether) A pressure-sensitive adhesive prepared by preparing the above-mentioned composition under the conditions described above was applied onto a polybutadiene foam (thickness: 0.4 m) and dried and conditioned. At that time, the water content of the adhesive is about 20% based on gelatin. and according to the prescribed method (JIS-20
237), the result of measuring the pole tag value is as follows.

20℃ 65%−・−−m−・−・−Ball tack value
1035℃ 65%-・-・～・-Pole tack value 1
4 [2] Blend> Low molecular weight water-soluble gelatin 70 parts by weight High molecular weight acid-decomposed gelatin 30 Water
200 ・Polyglycerin
250 “Glycerin
5o Crosslinking agent (polyethylene glyco 15)
- diglycidyl ether) (n is about 22) An adhesive prepared by preparing the composition as described above under the conditions described above is applied onto a polybutadiene foam having a thickness of 0.4 mm (1),
The pole tack value was measured in the same manner as above, and the results are as follows.

20℃ 65%---Ball cook value 93
5℃ 65%・−・・−1−−−−−Ball tack value
As is clear from the above explanations and the results of the examples, the adhesive according to the present invention uses low molecular weight water-soluble gelatin and/or high molecular weight decomposed gelatin, which are biologically derived substances, to be applied to the skin. It eliminates the need for irritating gelling inhibitors, and uses polyhydric alcohols and epoxy compounds containing alkylene oxide segments, which are harmless to the human body and cause almost no skin Tf irritation, as plasticizers, crosslinking agents, or grafting agents. There is almost no rash or skin irritation. Moreover, these crosslinking agents or grafting agents form a three-dimensional structure due to intermolecular interactions such as strong crosslinking or weak hydrogen bonds between gelatin molecules, and the grafting causes plasticization of gelatin. It exhibits constant adhesive properties that are unaffected by temperature and humidity, and can satisfactorily eliminate drawbacks such as adhesive residue, physical peeling during stringing and peeling, and 1ξ irritation.

Therefore, the adhesive of the present invention can be particularly suitably used as an adhesive for medical tapes, surge force rapes, burn covers, bioelectrodes, and the like.

Claims (1)

[Claims] An adhesive comprising a water-soluble gelatin with a low molecular weight and/or a decomposed gelatin with a higher molecular weight, an epoxy compound having a polyhydric alcohol and an alkylene oxide segment, and water.