JP2001104467A - Medical patch and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical patch used for external applications including first-aid patches and large patches, dressings and drapes in medical and hygieniu fields and a method of manufacturing the same. SOLUTION: A pressure-sensitive adhesive layer is formed on one side of a backing film, the pressure-sensitive adhesive layer is principally a copolymer whose gel content is 0 wt.% and average molecular weight is one milion or higher and which is obtained by copolymerizing a monomer mixture containing 40 to 90 wt.% alkylester acrylate monomer and 10 to 60 wt.% ethylenically unsaturated monomer containing an alkoxy group. Even if gel accounts practically 0 wt.%, due to a specific monomer constituent and weight average molecular weight, the patch is characterized by non-peeling of ends during application, nonpresence of a residual adhesive on the skin after application, good skin adhesiveness and cohesion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical patch for external use in the field of medical hygiene and a method for producing the same, and more particularly to a medical patch, a large-scale adhesive plaster, a dressing material, a drape material and the like. A medical patch to be used is provided.

[0002]

2. Description of the Related Art A medical adhesive material is usually one in which a pressure-sensitive adhesive layer is provided on one surface of a substrate film, and is used by being adhered to a skin surface to be applied via the adhesive layer.

[0003] The pressure-sensitive adhesive layer in such a medical patch generally needs to be firmly adhered and fixed to the skin surface, which may cause skin irritation at the time of peeling. May cause itching and sometimes inflammation of the skin.

Further, since the skin surface has an irregular and complicated surface shape, the adhesive layer cannot completely adhere (adhere) to the skin surface to which it is applied, and particularly, the medical treatment for a long period of time. In application of the adhesive material for use, a delicate balance between the internal cohesive force of the adhesive layer and the skin adhesive force is required.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and is intended to provide a copolymer having a specific composition and having a gel fraction of substantially 0% by weight. It has been found that a medical patch having excellent skin adhesion and internal cohesion can be obtained by using a pressure-sensitive adhesive layer as a main component, and the present invention has been completed.

[0006]

That is, the present invention relates to a patch comprising a substrate film having a pressure-sensitive adhesive layer provided on one surface thereof, wherein the pressure-sensitive adhesive layer comprises an alkyl acrylate monomer 40 Of a monomer mixture containing 10 to 60% by weight of an alkoxy group-containing ethylenically unsaturated monomer and having a gel fraction of substantially 0% by weight and a weight average molecular weight of 100%. An object of the present invention is to provide a medical patch characterized by being formed mainly of 10,000 or more copolymers.

Further, the present invention provides a monomer mixture containing 40 to 90% by weight of an acrylic acid alkyl ester monomer and 10 to 60% by weight of an alkoxy group-containing ethylenically unsaturated monomer using ethyl acetate as a polymerization solvent. In the presence of azobisisobutyronitrile, the concentration of monomers
By performing the copolymerization reaction by adjusting the amount to 0 to 70% by weight, a copolymer having a gel fraction of substantially 0% by weight and a weight average molecular weight of 1,000,000 or more is obtained. An object of the present invention is to provide a method for producing a medical patch, wherein an adhesive layer is provided on one surface of a substrate film.

In particular, the weight average molecular weight of the copolymer is 100
It is preferable to adjust so as to be 10,000 to 2.5 million.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, a medical patch of the present invention comprises a pressure-sensitive adhesive layer 2 on one side of a base film 1.
Is provided.

The base film in the present invention includes urethane polymers such as polyether urethane and polyester urethane, amide polymers such as polyether polyamide block polymer, acrylic polymers such as polyacrylate, polyethylene and polypropylene.
It can be obtained from materials such as polyolefin-based polymers such as ethylene / vinyl acetate copolymer and polyester-based polymers such as polyether polyester. Also,
These base films are preferably selected from materials having a water vapor permeability in order to prevent stuffiness and whitening when applied to the skin surface.For example, a urethane-based or amide-based film is preferably used. It is suitable. The base film may be made of any one of the above materials, or may be a laminated film in which a plurality of films made of any material are stacked.

When the above substrate film is applied to the skin surface
In order to avoid discomfort, the thickness should be 1
0 to 100 μm, preferably about 20 to 40 μm
Good. In addition, the ability to follow the skin when affixed to the skin surface
In order to improve the tensile strength, the tensile strength should be 100 to 900 kg /
cm^Two, 100% modulus is 10-100 kg / cm
^TwoIt is preferable to adjust to the extent. Adjusted to this range
When a base film is used, the magnitude of motion
It is effective when affixed to a clean skin surface.

It is effective to use not only a non-porous film but also a water-permeable and water-impermeable porous film as the base film from the viewpoint of preventing stuffiness during application. In the case of such a film, the material is not particularly limited, and can be easily obtained by performing a known porous technology. In the case of a non-porous film, the tendency that the water vapor permeability decreases as the film thickness increases becomes remarkable, but in the case of a porous film, the water vapor permeability decreases in proportion to the thickness and thus is useful because it does not remarkably decrease. It is.

The medical patch of the present invention can be suitably used for an emergency bandage, a large bandage, a dressing material, a drape material, and the like. Is usually about 100 μm), it is preferable to use a porous film. As the base film suitable for the porous film, a porous plastic film made of a polyolefin resin is preferable, and for example, resins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer can be used. In particular, it is preferable to use a linear low-density polyethylene resin from the viewpoint of productivity and workability. The linear low-density polyethylene resin is a copolymer of ethylene and an α-olefin, and examples of the α-olefin include butene, hexene, and octene.

On the other hand, the pressure-sensitive adhesive layer in the present invention comprises:
40 to 90% by weight of an alkyl acrylate monomer,
The copolymer is mainly composed of 10 to 60% by weight of an alkoxy group-containing ethylenically unsaturated monomer, and has a gel fraction of substantially 0% by weight. Things.

The acrylic acid alkyl ester monomer is a component for imparting tackiness and skin adhesion to the pressure-sensitive adhesive layer. Particularly, the alkyl group has 6 or more carbon atoms in the alkyl group, and particularly 6 to 18 long-chain alkyl esters. It is effective to use. Also,
The acrylic acid alkyl ester monomer has an advantage that it has relatively little irritation to the skin and the adhesiveness hardly decreases even after long-term use.

Specific examples of such alkyl acrylates include butyl, propyl, octyl, nonyl, decyl, dodecyl, and lauryl esters of acrylic acid. be able to.
In addition, even if these alkyl ester chains are linear,
It goes without saying that it may be a branched chain.

The above-mentioned alkyl acrylate forms a tacky polymer by copolymerizing with an unsaturated monomer described below, but in the present invention, it ranges from 40 to 90% by weight, preferably from 50 to 75% by weight. It is desirable to copolymerize with. When the copolymerization amount of the acrylic acid alkyl ester is less than 40% by weight, the obtained adhesive polymer does not have sufficient skin adhesion, and when the copolymerization amount exceeds 90% by weight, aggregation occurs. A decrease in force is observed, and a glue residue phenomenon may occur when peeling off from the skin surface.

The alkoxy group-containing ethylenically unsaturated monomer copolymerized with the acrylic acid alkyl ester is a component that imparts water vapor permeability to the obtained copolymer. Therefore, 10 to 60% by weight, preferably 25 to 60% by weight in the copolymer
It is desirable to copolymerize in the range of 50% by weight. Examples of such unsaturated monomers include methoxypolyethylene glycol acrylate, ethoxydiethylene glycol acrylate, butoxydiethylene glycol acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, and butoxyethyl acrylate.
It is preferable to use an alkoxyalkyl acrylate having from 4 to 4 alkoxy groups.

In the present invention, it is preferable to copolymerize a carboxyl group-containing ethylenically unsaturated monomer together with the alkoxy group-containing unsaturated monomer. Copolymerization of the carboxyl group-containing ethylenically unsaturated monomer improves the cohesive strength of the obtained copolymer, and is therefore an important monomer in preparing a pressure-sensitive adhesive. However, when the monomer is copolymerized in a large amount, an improvement in cohesion can be expected, but the skin irritation gradually increases. Therefore, in the present invention, when copolymerizing the monomer, 1 to 10% by weight,
Preferably, the copolymerization ratio is about 3 to 7% by weight. Representative examples of such monomers include acrylic acid, itaconic acid, crotonic acid, fumaric acid, (anhydrous) maleic acid, and the like. Among these, acrylic acid is preferred as a monomer in terms of copolymerizability, handleability, and the like.

As the copolymer contained in the pressure-sensitive adhesive of the present invention, copolymers of the above monomers can be used. Styrene, vinyl acetate, N-
A monomer such as vinyl-2-pyrrolidone may be appropriately copolymerized as needed.

The above-mentioned copolymer in the medical patch of the present invention preferably has a glass transition temperature of 250 ° K or lower. That is, by setting the glass transition temperature to 250 ° K or lower, the skin adhesive force important as a patch can be sufficiently exhibited.

The weight average molecular weight of the copolymer is 100
It is desirable to adjust the number to at least 10,000, preferably 1,000,000 to 2.5 million, and more preferably to about 1.3 million to 1.9 million. In other words, the medical patch of the present invention uses an electron beam, a γ-ray,
In order to have an appropriate internal cohesive force without irradiating ionizing radiation such as a line, the weight average molecular weight is preferably set to be relatively high, and is preferably 1,000,000 or more. If the weight-average molecular weight is too high, the cohesive force increases, but the pressure-sensitive adhesive layer becomes too hard, and a peeling phenomenon of the end of the adhesive material occurs during use during application, and in some cases, the adhesive material may fall off. Therefore, it is preferable to suppress the weight average molecular weight to 2.3 million or less.

In the present invention, since the pressure-sensitive adhesive layer itself has a practically sufficient cohesive force, an internal cross-linking reaction is caused by irradiating ionizing radiation such as γ-ray which causes a decrease in skin adhesive force. However, depending on the type of the monomer to be subjected to the copolymerization reaction exemplified above, even if the weight average molecular weight is 1,000,000 or more, there is a possibility that the cohesion may be slightly lacking. In such a case, irradiation with an ionizing irradiation beam is not excluded. When irradiation with ionizing radiation is required, the irradiation dose may be about 20 to 50 kGy, preferably about 25 to 35 kGy.

Further, such a copolymer is mainly used,
A pressure-sensitive adhesive obtained by blending various additives such as a plasticizer and a softener, a filler, and a tackifier as necessary is formed in a layer on one surface of the base film, and a pressure-sensitive adhesive layer is formed. Become. At this time, the gel fraction of the pressure-sensitive adhesive layer, that is, the content of the solvent-insoluble component is substantially 0% by weight. In the present invention, approximately 0% by weight means 0.1% by weight. It includes a value of about several percent by weight.

In the present invention, the gel fraction was determined by immersing a dried sample in ethyl acetate at room temperature for 10 days, using a polytetrafluoroethylene membrane (NTF membrane, manufactured by Nitto Denko Corporation) having an average pore diameter of 0.2 μm. The insolubles were separated by filtration, dried and calculated by the ratio to the dry sample weight before immersion.

The thickness of the pressure-sensitive adhesive layer obtained as described above is preferably about 10 to 60 μm.
If the thickness is less than 10 μm, it may not be able to exhibit sufficient skin adhesion when applied to the skin,
If the thickness exceeds 60 μm, sufficient water vapor permeability cannot be obtained as a whole of the adhesive material, and skin irritation may be manifested when applied for a long time.

The medical patch of the present invention has the above-mentioned constitution and preferably has water vapor permeability, but the moisture permeability of the entire patch is at least 300 g / m ² ···.
24 hr./40° C./30%R. H. , Preferably 300
^{~2000g / m 2 · 24hr · 40} ℃ · 30% R.
H. Set to the range. When a patch is applied to the skin surface of a person, it depends on the individual differences and the location of the patch.
^{00g / m 2 · 24hr · 40} ℃ · 30% R. H. If it is not made to have a water vapor permeability, when it is applied to a site where the amount of sweating is large, sufficient moisture permeability cannot be exhibited, which causes stuffiness.

Although the medical patch of the present invention has the above-mentioned constitution, usually, the exposed surface of the pressure-sensitive adhesive layer has
Generally, a release sheet having a surface subjected to a release treatment such as a silicone treatment is temporarily attached.

The medical patch of the present invention obtained as described above can be used by sticking a pressure-sensitive adhesive layer to an arm or other affected area as shown in FIG. The adhesive material also expands and contracts in accordance with the expansion and contraction operation of, and sweat from the skin surface becomes water vapor 3 and diffuses out of the body.

An example of the method for producing the medical patch of the present invention will be briefly described below.

First, a monomer mixture containing 40 to 90% by weight of the above-mentioned alkyl acrylate monomer and 10 to 60% by weight of the alkoxy group-containing ethylenically unsaturated monomer,
Preferably alkyl acrylate monomer 40 to 8
0% by weight, alkoxy group-containing ethylenically unsaturated monomer 1
A monomer mixture consisting of 0 to 50% by weight and 1 to 10% by weight of a carboxyl group-containing ethylenically unsaturated monomer is uniformly dissolved in ethyl acetate as a polymerization solvent.

As the polymerization solvent, in the case of solution polymerization, any solvent can be used as long as it can dissolve the monomer mixture. Therefore, an organic solvent such as toluene, benzene, acetone, tetrahydrofuran, hexane, cyclohexane, or ethyl acetate can be used. However, it is preferable to use a high-boiling solvent in order to safely carry out the polymerization reaction, and it is preferable to use an organic solvent in which active hydrogen is hardly drawn out in order to obtain a high molecular weight copolymer. Ethyl acetate is suitable as such an organic solvent.

Next, azobisisobutyronitrile as a polymerization initiator is blended, and a copolymerization reaction is carried out while controlling the reaction temperature to about 50 to 65 ° C. In carrying out the copolymerization reaction, the concentration of the total amount of monomers at the beginning of the reaction is adjusted to 50 to 70% by weight, preferably 55 to 65% by weight. When the concentration is low, the polymerization reaction is diluted, and there is a possibility that a copolymer having a weight average molecular weight of less than 1,000,000 may be obtained. Therefore, it is preferable to set the concentration as high as possible. However, if the concentration is too high, it is difficult to control the heat of reaction generated during the copolymerization reaction, and the obtained copolymer may be gelled. Therefore, it is effective to set the concentration to about 50 to 70% by weight. It is.

The copolymer obtained as described above has a gel fraction of substantially 0% by weight. In the present invention, the copolymer is mainly used, and if necessary, a plasticizer or a softener is used. ,
Filler, various additives such as tackifier, blending a diluting solvent such as ethyl acetate to prepare a solution for pressure-sensitive adhesive,
This is directly applied to one side of the substrate film and dried to form a pressure-sensitive adhesive layer, thereby producing the medical patch of the present invention. Alternatively, the pressure-sensitive adhesive solution is applied to a release-treated surface of a release sheet having been subjected to a release treatment such as silicone treatment on the surface, and dried to form a pressure-sensitive adhesive layer. Is transferred to one side of the base film to produce the medical patch of the present invention.

[0035]

Since the medical patch of the present invention has the above-mentioned constitution, it is less irritating to the skin and is particularly useful for long-term application. Further, since the weight average molecular weight of the copolymer which is the main component of the pressure-sensitive adhesive layer is set to a high molecular weight of 1,000,000 or more, even if the gel fraction is substantially 0% by weight, during the application, There is no terminal peeling or adhesive residue when peeled after use after application, and it has both excellent skin adhesion and cohesiveness. Therefore, the medical patch of the present invention is an optimal patch for applications such as dressing materials, bandages, emergency bandages, and drape materials.

[0036]

EXAMPLES Examples of the present invention will be described below in more detail, but the present invention is not limited thereto, and various applications can be made without departing from the technical idea of the present invention. It is possible. In the following text, “parts” means “parts by weight”, and “%” means “% by weight”.

Example 1 A monomer mixture comprising 62 parts of isononyl acrylate, 35 parts of 2-methoxyethyl acrylate and 3 parts of acrylic acid was uniformly dissolved and mixed in 80 parts of ethyl acetate, and azobis as a polymerization initiator was mixed. A copolymerization reaction was carried out by adding 0.3 parts of isobutyronitrile. After polymerization was carried out at 50 to 65 ° C. for about 10 hours, the temperature was raised to 78 ° C. and polymerization (aging) was carried out for 2 hours. The glass transition temperature of the obtained copolymer was 207 K, the gel fraction was 0%, and the weight average molecular weight was 1.32 million.

Next, a toluene solution of this copolymer was applied to the treated surface of a release sheet having one surface subjected to silicone treatment so that the thickness after drying was 25 μm.
After drying for a minute, a pressure-sensitive adhesive layer was formed.

Next, on the surface of the obtained pressure-sensitive adhesive layer, the treated surface of a polyether polyamide block polymer sheet (thickness: 30 μm, trade name: PEBAX3533, manufactured by Toray Industries, Inc.) having one surface subjected to corona discharge treatment was applied. The medical patch of the present invention was produced by sticking and pressing.

Example 2 A monomer mixture consisting of 70 parts of 2-ethylhexyl acrylate, 25 parts of 2-ethoxyethyl acrylate and 5 parts of acrylic acid was uniformly dissolved and mixed in 45 parts of ethyl acetate. Similarly, a pressure-sensitive adhesive layer was formed. In addition, the glass transition temperature of the obtained copolymer was 212.
° K, the gel fraction was 0%, and the weight average molecular weight was 1.51 million.

Next, on the surface of the obtained pressure-sensitive adhesive layer,
A treated surface of a polyether polyester sheet (thickness: 30 μm, manufactured by Nippon Synthetic Chemical Co., Ltd., trade name: Flecron M type) having one surface subjected to corona discharge treatment was attached and crimped to produce a medical patch of the present invention. .

Example 3 A pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that a monomer mixture consisting of 65 parts of isononyl acrylate and 35 parts of 2-methoxyethyl acrylate was uniformly dissolved and mixed in 70 parts of ethyl acetate. An agent layer was formed. In addition, the gel fraction of the obtained copolymer was 0.1%, and the weight average molecular weight was 1.3 million.

Next, on the surface of the obtained pressure-sensitive adhesive layer,
A treated surface of a sheet made of polyether polyamide block polymer (same as described above) having one surface subjected to corona discharge treatment was adhered and pressure-bonded to produce a medical adhesive material of the present invention.

Example 4 A monomer mixture consisting of 65 parts of isononyl acrylate, 30 parts of 2-methoxyethyl acrylate and 5 parts of acrylic acid was uniformly dissolved and mixed in 40 parts of ethyl acetate.
A pressure-sensitive adhesive layer was formed in the same manner as in Example 1. In addition, the gel fraction of the obtained copolymer was 0.1%, and the weight average molecular weight was 1.87 million.

Next, on the surface of the obtained pressure-sensitive adhesive layer,
A treated surface of a sheet made of polyether polyamide block polymer (same as described above) having one surface subjected to corona discharge treatment was adhered and pressure-bonded to produce a medical adhesive material of the present invention.

Example 5 A monomer mixture comprising 62 parts of isononyl acrylate, 35 parts of 2-methoxyethyl acrylate and 3 parts of acrylic acid was uniformly dissolved and mixed in 25 parts of ethyl acetate.
A pressure-sensitive adhesive layer was formed in the same manner as in Example 1. In addition, the glass transition temperature of the obtained copolymer was 207 K, the gel fraction was 0%, and the weight average molecular weight was 2,240,000.

Next, on the surface of the obtained pressure-sensitive adhesive layer,
A treated surface of a sheet made of polyether polyamide block polymer (same as described above) having one surface subjected to corona discharge treatment was adhered and pressure-bonded to produce a medical adhesive material of the present invention.

Example 6 Example 1 was repeated except that a monomer mixture consisting of 70 parts of 2-ethylhexyl acrylate, 25 parts of 2-ethoxyethyl acrylate and 5 parts of acrylic acid was uniformly dissolved and mixed in 25 parts of ethyl acetate. Similarly, a pressure-sensitive adhesive layer was formed. In addition, the glass transition temperature of the obtained copolymer was 212.
° K, gel fraction 0%, weight average molecular weight 203
It was 10,000.

Next, on the surface of the obtained pressure-sensitive adhesive layer,
A treated surface of a sheet made of polyether polyamide block polymer (same as described above) having one surface subjected to corona discharge treatment was adhered and pressure-bonded to produce a medical adhesive material of the present invention.

Example 7 A monomer mixture comprising 62 parts of isononyl acrylate, 35 parts of 2-methoxyethyl acrylate and 3 parts of acrylic acid was uniformly dissolved and mixed in 25 parts of toluene, and benzoyl peroxide was used as a polymerization initiator. A pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that 0.3 part was added. In addition,
The glass transition temperature of the obtained copolymer was 207 ° K, the gel fraction was 0%, and the weight average molecular weight was 1,240,000.

Next, on the surface of the obtained pressure-sensitive adhesive layer,
A treated surface of a sheet made of polyether polyamide block polymer (same as described above) having one surface subjected to corona discharge treatment was adhered and pressure-bonded to produce a medical adhesive material of the present invention.

Comparative Example 1 A medical patch was prepared in the same manner as in Example 3, except that toluene was used instead of ethyl acetate. The copolymer had a gel fraction of 0% and a weight average molecular weight of 82%.
It was 10,000.

Comparative Example 2 A medical patch was produced in the same manner as in Example 2 except that the amount of ethyl acetate was changed to 120 parts. The glass transition temperature of the copolymer was 212 ° K, the gel fraction was 0%, and the weight average molecular weight was 9240.

Comparative Example 3 A medical patch was produced in the same manner as in Example 2, except that ethyl acetate was replaced with toluene and the amount was changed to 80 parts. The glass transition temperature of the copolymer is 207 °
K, the gel fraction was 0%, and the weight average molecular weight was 48.8.
It was 10,000.

Comparative Example 4 Example 4 was repeated except that the polymerization initiator was changed from azobisisobutyronitrile to 0.3 parts of benzoyl peroxide.
A medical patch was produced in the same manner as in Example 4. The copolymer had a gel fraction of 46.9%, a weight average molecular weight of 1,480,000, and a high gel fraction.

Comparative Example 5 A medical patch was produced in the same manner as in Example 4 except that the polymerization solvent ethyl acetate was changed to toluene. The gel fraction of the copolymer was 0.1%, and the weight average molecular weight was 815,000.

The following tests were performed on the medical patches obtained in the above Examples and Comparative Examples, and the results are shown in Table 1.

<Gel Fraction> A predetermined amount of the dried polymer was extracted in ethyl acetate at room temperature for 10 days, and the residue (insoluble matter) was subjected to a polytetrafluoroethylene membrane (average pore size: 0.1%).
2 μm, Nitto Denko Corporation, NTF membrane), filtered, dried and determined by gravimetric method. The gel fraction was calculated by the following equation.

[0059]

(Equation 1)

<Terminal peeling> Each medical patch is 20 mm
A test piece was cut into a size of × 50 mm. The chest of the male subject was disinfected with an alcohol disinfectant, air-dried, and a test piece was attached while paying attention to prevent wrinkles and stretching. Bathing is possible during the sticking test, but care was taken not to rub the sticking site with a towel or the like.

On the 7th day after the application, the adhered state of the test piece (terminal peeled state) was visually observed, and judged according to the following evaluation criteria.

A: Peeling of the end is less than 20% of the area of the test piece. C: Peeling off of the terminal is 20% or more and 60% of the area of the test piece.
Is less than. C: Peeling off is 60% or more of the area of the test piece.

<Glue Remaining> After the above-mentioned terminal peeling test was performed, each test piece was peeled off, and the state of the glue remaining on the skin surface was visually observed, and was judged according to the following criteria.

〇: Adhesive residue is less than 10% of the area of the test piece. Δ: Adhesive residue is 10% or more and less than 50% of the area of the test piece. X: The adhesive residue is 50% or more of the area of the test piece.

<Weight Average Molecular Weight> The weight average molecular weight was measured by gel permeation chromatography (GPC). The measurement sample was dissolved in tetrahydrofuran, and the soluble component passing through a 0.45 μmφ membrane filter was measured and calculated in terms of polystyrene.

[0066]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a medical patch of the present invention.

FIG. 2 is a perspective view illustrating a use state of the medical patch of the present invention.

[Explanation of symbols]

 1 base film 2 pressure-sensitive adhesive layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsuji Sugii 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 4C081 AA03 AA12 BB04 CA051 CA081 CC01 DA02 DC02 DC04 EA02

Claims (6)

[Claims] 1. An adhesive material comprising a substrate film having a pressure-sensitive adhesive layer provided on one side thereof, wherein said pressure-sensitive adhesive layer comprises 40 to 90% by weight of an alkyl acrylate monomer and ethylene containing an alkoxy group. 10-60% by weight of unsaturated monomer
For medical use, characterized by being formed mainly of a copolymer having a gel fraction of substantially 0% by weight and a weight average molecular weight of 1,000,000 or more obtained by copolymerizing a monomer mixture containing Adhesive material. 2. A copolymer comprising 40 to 80% by weight of an alkyl acrylate monomer, 10 to 50% by weight of an alkoxy group-containing ethylenically unsaturated monomer, and 1 to 50% by weight of a carboxyl group-containing ethylenically unsaturated monomer. The medical patch according to claim 1, which is a copolymer comprising 10% by weight. 3. A copolymer having a weight average molecular weight of 1,000,000 to 3,000,000.
The medical patch according to claim 1, wherein the amount is 2.5 million. 4. An alkyl acrylate monomer 40.
To 90% by weight and a monomer mixture containing 10 to 60% by weight of an alkoxy group-containing ethylenically unsaturated monomer in the presence of azobisisobutyronitrile using ethyl acetate as a polymerization solvent. Monomer concentration of 50-70% by weight
To obtain a copolymer having a gel fraction of substantially 0% by weight and a weight-average molecular weight of 1,000,000 or more. A method for producing a medical patch, wherein the method is provided on one side of a film. 5. A copolymer comprising 40 to 80% by weight of an alkyl acrylate monomer, 10 to 50% by weight of an alkoxy group-containing ethylenically unsaturated monomer, and 1 to 5% of a carboxyl group-containing ethylenically unsaturated monomer. The method for producing a medical patch according to claim 4, which is a copolymer comprising 10% by weight. 6. The copolymer has a weight-average molecular weight of 1,000,000 or more.
The method for producing a medical patch according to claim 5, wherein the amount is 2.5 million.