JP2002053461A - Medical adhesive composition, method for producing the same and adhesive tape or sheet using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical adhesive composition used for pasting on the skin in a medical or hygienic field, a method for producing the same and an adhesive tape or sheet by using the composition. SOLUTION: This medical adhesive composition is obtained by copolymerizing a mixture containing an acrylic acid alkyl ester having a 4-12C alkyl group with (meth)acrylic acid, a methacrylic acid alkyl ester having a 1-4C alkyl group and a multi-functional monomer having >=2 unsaturated double bonds in its molecule. Preferably, the gel fraction in the composition is adjusted in 40-70 wt.% range. Also, it is preferable to prepare the adhesive composition by adding a chain transfer agent, hydrophilic alcohol, surfactant and polymerization initiator to the above monomer mixture in an aqueous medium and performing an emulsion polymerization. The adhesive composition is formed as a layered state having 15-70 μm thickness on the one surface of a substrate for producing the adhesive tape or adhesive sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical pressure-sensitive adhesive composition used for application to the skin in the field of medical hygiene, a method for producing the same, and a pressure-sensitive adhesive tape or sheet using the composition.

[0002]

2. Description of the Related Art In general, a medical pressure-sensitive adhesive composition used for application to the skin is formed as a pressure-sensitive adhesive layer in a layer on one surface of a substrate film, and a medical pressure-sensitive adhesive tape or sheet is prepared. Used for sticking.

[0003] The pressure-sensitive adhesive layer formed from the medical pressure-sensitive adhesive composition used in this manner generally needs to be firmly adhered and fixed to the skin surface, and at the same time, the cohesive force in the layer and the adhesive strength of the support. It should be excellent in so-called adhesive properties such as anchoring force of the steel.

Further, since it is used for application to the skin, it must be non-irritating to the skin surface to be applied, and must not exert physical pain when peeled from the skin surface to develop skin irritation. It is also required to have skin irritation properties.

[0005] Conventionally, as a medical pressure-sensitive adhesive composition,
An acrylic pressure-sensitive adhesive composition containing alkyl acrylate as a main component and a rubber pressure-sensitive adhesive composition containing a synthetic rubber or a natural rubber as a main component are generally used. However, it is difficult to adjust the adhesive properties of rubber-based adhesives, and natural rubber may cause allergies.There are some difficulties in handling, so adjustment of the adhesive properties by polymerization method, polymerization composition, compounding, etc. There have been relatively many studies of acrylic pressure-sensitive adhesive compositions that are easy to perform.

[0006] As described above, the acrylic pressure-sensitive adhesive composition is relatively easy to adjust the pressure-sensitive adhesive properties and can provide a well-balanced pressure-sensitive adhesive. ) Is not sufficiently satisfactory, and various studies have been made to improve this point.

For example, in order to improve skin adhesion,
The alkyl group as a tackifier has 4 to 12 carbon atoms.
It is only necessary to increase the copolymerization amount of the alkyl acrylate or to use an alkyl acrylate having a long alkyl chain, but on the other hand, a cross-linking treatment is required because the retention is lowered. As a typical crosslinking treatment, a method of adding an external crosslinking agent such as a polyisocyanate, an amine or an epoxy compound, and a method of copolymerizing a crosslinking monomer are used.

However, the cross-linking treatment by adding a cross-linking agent has problems of control of reaction time and pot life, and it is difficult to suppress variation in adhesive properties between lots.
Strict control in the manufacturing process is required. In other words, it has not yet been obtained that the required properties of the medical adhesive composition obtained by adding skin non-irritability to the skin adhesive force, holding power, and anchoring force as adhesive properties are sufficiently balanced. It is a fact.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and is intended to obtain a composition which satisfies each required property as a medical pressure-sensitive adhesive composition. It has been found that a copolymer comprising a specific monomer composition, especially a composition containing a water-dispersible copolymer obtained by emulsion polymerization exhibits excellent adhesive properties and non-irritating properties on the skin. It was completed.

[0010]

That is, the present invention provides a method for producing a compound having 4 carbon atoms.
An alkyl acrylate having an alkyl group of from 1 to 12, (meth) acrylic acid, an alkyl methacrylate having an alkyl group of from 1 to 4 carbon atoms, and a methacrylate having two or more unsaturated double bonds in the molecule. An object of the present invention is to provide a medical pressure-sensitive adhesive composition obtained by copolymerizing a monomer mixture containing a functional monomer.

Further, the present invention provides an alkyl acrylate having an alkyl group having 4 to 12 carbon atoms, (meth) acrylic acid, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and two acrylates in a molecule. Emulsion polymerization of a monomer mixture containing a polyfunctional monomer having the above unsaturated double bond in an aqueous medium in the presence of a chain transfer agent, a hydrophilic alcohol, a surfactant, and a polymerization initiator. It is intended to provide a method for producing a medical pressure-sensitive adhesive composition characterized by the following.

Further, the present invention provides a pressure-sensitive adhesive tape or sheet comprising the above-mentioned medical pressure-sensitive adhesive composition formed in a layer having a thickness of 15 to 70 μm on one surface of a support.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The medical pressure-sensitive adhesive composition of the present invention comprises an alkyl acrylate having an alkyl group having 4 to 12 carbon atoms, (meth) acrylic acid, and methacryl having an alkyl group having 1 to 4 carbon atoms. It is obtained by copolymerizing a mixture containing an acid alkyl ester and a polyfunctional monomer having two or more unsaturated double bonds in the molecule.

As the above-mentioned alkyl acrylate, alkyl groups such as butyl group, pentyl group,
Esters in which an alkyl group having 4 to 12 carbon atoms such as a hexyl group, a nonyl group, an octyl group, a decyl group, and a dodecyl group can be used. These alkyl groups may be linear or branched. It may be. Particularly preferred alkyl acrylates include 2-ethylhexyl acrylate and isooctyl acrylate.

Further, the alkyl methacrylate to be copolymerized with the alkyl acrylate described above includes:
As the alkyl group, for example, an ester to which an alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, an isobutyl group, a 2-ethylhexyl group, and a lauryl group can be used. The groups may be straight-chain or branched. Of these, particularly preferred alkyl methacrylates include methyl methacrylate and lauryl methacrylate.

Further, the polyfunctional monomer having two or more unsaturated double bonds in the molecule acts as an internal crosslinking agent and contributes to imparting a cohesive force. Acrylate, trimethylpropanol triacrylate, dipentaerythritol hexaacrylate, pentaerythritol triacrylate, and the like can be used.

The above monomers can be copolymerized to obtain a copolymer. The amount of each monomer is 100 parts by weight of the alkyl acrylate and (meth) acrylic acid per 100 parts by weight.
To 15 parts by weight, alkyl methacrylate 2 to 50
Parts by weight, 0.001 to 1 part by weight of a polyfunctional monomer.

If the amount of (meth) acrylic acid is less than 1 part by weight, the adhesion to the skin surface tends to be insufficient, and if it is more than 15 parts by weight, the adhesion to the skin surface is unfavorable. Although the adhesion increases, the water resistance decreases, which is not preferable. On the other hand, when the blending amount of the alkyl methacrylate is less than 2 parts by weight, the glass transition temperature of the copolymer decreases, and as a result, the apparent tackiness becomes too strong when the pressure-sensitive adhesive layer is formed. There is a possibility that the amount is more than 50 parts by weight, which is not preferable because the glass transition temperature increases and the apparent tackiness tends to decrease.

Further, when the compounding amount of the polyfunctional monomer is 0.0
When the amount is less than 01 parts by weight, it is difficult to impart sufficient internal cohesiveness to the obtained copolymer, and when an adhesive tape or sheet is formed, the adhesive layer undergoes cohesive failure and the skin surface as an adherend May cause the adhesive residue phenomenon. If the amount of the polyfunctional monomer exceeds 1 part by weight, the internal cohesiveness is increased and the pressure-sensitive adhesive tends to be hard, which is not preferable because it mainly causes a decrease in the pressure-sensitive adhesiveness.

The medical pressure-sensitive adhesive composition of the present invention is obtained by copolymerizing a mixture of each of the above-mentioned monomers. In order to achieve an excellent balance of anchoring force and to achieve skin non-irritancy (reduction of physical irritation during peeling), the gel fraction in the pressure-sensitive adhesive composition is 40 to 70% by weight, preferably 45 to 60% by weight. % Is preferably adjusted. If the gel fraction is too small, the viscosity of the pressure-sensitive adhesive composition increases and the adhesive force increases, and as a result, a phenomenon of adhesive residue on the skin surface or a tendency to increase skin irritation tends to occur. If the fraction is too large, the elasticity of the pressure-sensitive adhesive composition increases, causing a decrease in the adhesive force, and as a result, peeling from the skin surface (fall-out phenomenon) occurs.

Further, the internal cohesion is adjusted by adjusting the gel fraction.
That is, when the weight-average molecular weight of the soluble component is adjusted to be in the range of 200,000 to 400,000, and preferably 250,000 to 300,000, the skin adhesive strength, the holding power, and the anchoring power can be balanced,
It is preferable because skin irritation can be reduced.

The gel fraction in the present invention means that a dried sample is immersed in toluene at room temperature for 7 days, and is subjected to a polytetrafluoroethylene membrane (Nitto Denko Corporation, NTF membrane) having an average pore diameter of 0.2 μm. It is a value calculated by filtering the insoluble matter, drying and calculating the ratio to the dry sample weight before immersion.

In obtaining the pressure-sensitive adhesive composition for medical use of the present invention, a monomer mixture obtained by mixing the above monomers is mixed with a chain transfer agent and a hydrophilic alcohol, a surfactant, a polymerization initiator in an aqueous medium. The mixture is mixed with an agent and heated to start an emulsion polymerization reaction to obtain a medical pressure-sensitive adhesive composition as a water-dispersible copolymer.

As the chain transfer agent, in order to trap a radical species in the emulsified monomer mixture and cause a chain transfer,
It is necessary to use a hydrophobic chain transfer agent, and specifically, a sulfur-based compound such as lauryl mercaptan or thioglycolic acid is used.

As the hydrophilic alcohol, aliphatic alcohols having 1 to 4 carbon atoms such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol and butyl alcohol can be used. It dissolves in an aqueous medium during polymerization and acts as a chain transfer agent.

The surfactant is important for improving the dispersion stability of the monomer in the aqueous medium during the emulsion polymerization and for maintaining a stable emulsion polymerization reaction.
Nonionic emulsifiers and reactive emulsifiers can be used alone or in combination of two or more. Among them, anionic emulsifiers such as fatty acid salts, higher alcohol sulfates, sulfosuccinates, and dialkylsulfosuccinates. Can be suitably used.

The polymerization initiator is required for emulsion polymerization, and uses a persulfate such as ammonium persulfate or potassium persulfate, or a peroxide such as hydrogen peroxide or benzoyl peroxide. Further, if necessary, a combination of a persulfate and a reducing agent such as a sulfite of an alkali metal or a bisulfite can be used as a redox-based polymerization initiator capable of initiating a polymerization reaction at a low temperature.

In the emulsion polymerization in the production method of the present invention, the above components are blended in an aqueous medium. The blending amounts of the above components are 0.001 to 2 parts by weight of a chain transfer agent, 0.001 to 2 parts by weight of a hydrophilic alcohol. 2 parts by weight, surfactant and polymerization initiator are optional amounts.

When the amount of the chain transfer agent or the hydrophilic alcohol is too small, the weight average molecular weight of the obtained copolymer becomes too large, so that the adhesive force as an adhesive property becomes poor.
Lack of polymerization stability causes the entire reaction system to gel during the polymerization, or insufficient adhesion to the skin surface. On the other hand, if the compounding amount is too large, the polymerization average molecular weight of the obtained copolymer is too small, and the cohesive force as the adhesive property is deteriorated, or glue remains on the skin surface, and the skin irritation becomes strong Because of the tendency, it is difficult to exhibit the balance of the adhesive property and the non-irritating property of the skin.

The polymerization method is not particularly limited as long as the above components can be blended in an aqueous medium and emulsion polymerization can be carried out. A batch polymerization method in which the components are reacted in a batch charge or a seed method in which emulsion polymerization is carried out in the presence of a seed emulsion (seed). It may be appropriately selected from a polymerization method, a multi-stage polymerization method in which the polymerization reaction is performed stepwise, a power feed polymerization method in which the polymerization reaction is performed by continuously changing the composition ratio of the monomer composition, and the like.

The medical pressure-sensitive adhesive composition of the present invention obtained as described above has a thickness of 15 to 70 μm on one surface of a support.
Preferably, it is formed as a pressure-sensitive adhesive layer having a thickness of 20 to 65 μm to obtain a pressure-sensitive adhesive tape or sheet of the present invention.

Examples of the support used include various plastic films such as polyethylene, polypropylene, ethylene / vinyl acetate copolymer, and polyester, and woven and nonwoven fabrics, knitted fabrics, papers, metal foils, and the like made of these plastics.
Alternatively, a laminated film of these or the like can be used.

The pressure-sensitive adhesive tape or sheet of the present invention is not particularly limited in its shape as long as it is used for medical purposes. Examples thereof include emergency bandages, wound bands, large bandages, dressing materials,
Suitable for drape materials, etc.

The above-mentioned pressure-sensitive adhesive tape or sheet is
For long products, apply a release agent such as silicone resin or fluororesin to the back of the support and wind it so that the adhesive layer is in contact with the back of the support to form a roll, or use a release sheet that has been subjected to release treatment. It is preferable that the sheet is temporarily attached to the surface of the pressure-sensitive adhesive layer.

[0035]

Since the medical pressure-sensitive adhesive composition of the present invention has the above constitution, when it is formed into a layer on one surface of a support and applied to a skin surface as a pressure-sensitive adhesive tape or sheet, it can be applied to the skin surface. It is less irritating and is particularly useful for long-term application. In addition, it has an excellent balance of skin adhesive strength, holding power, and anchoring power as adhesive properties, there is no peeling-off during use and no adhesive residue phenomenon at the time of peeling, and dressing materials, bandages, emergency bandages, drape materials, etc. Pressure-sensitive adhesive tapes and sheets that are most suitable for the above applications.

[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 concept of the present invention. It is possible.

Example 1 950 g of 2-ethylhexyl acrylate, 50 g of methacrylic acid, lauryl methacrylate 100
g, 0.25 g of pentaerythritol triacrylate
To a monomer mixture consisting of 0.5 g of thioglycolic acid,
5 g of n-butyl alcohol was added, and 700 g of an aqueous solution containing 1% by weight of a surfactant (trade name: Hytenol N-17, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added thereto. The mixture was emulsified using (manufactured by Tokushu Kikai) and heated to 70 ° C. while stirring.

Next, 1 g of potassium persulfate as a polymerization initiator was added with an aqueous solution dissolved in 15 g of water to start an emulsion polymerization reaction, and the reaction was continued for about 5 hours. after that,
The temperature was raised to 85 ° C., and an aging reaction was performed for 2 hours to complete the polymerization reaction, thereby obtaining a medical pressure-sensitive adhesive composition of the present invention.

Example 2 950 g of 2-ethylhexyl acrylate, 20 g of methacrylic acid, and 100 g of methyl methacrylate
g, 0.25 g of pentaerythritol triacrylate
Lauryl mercaptan 0.5
g and 5 g of n-butyl alcohol, and 500 g of an aqueous solution containing 1% by weight of a surfactant (trade name: Latemul AD25R, manufactured by Kao Corporation) was added thereto. Emulsified using
200 g of water was added to 50 g of the obtained emulsion, and the mixture was heated to 70 ° C. while stirring was continued.

Next, 1 g of potassium persulfate as a polymerization initiator was added with an aqueous solution dissolved in 15 g of water to start the emulsion polymerization reaction, and the polymerization reaction was continued for about 4 hours while gradually adding the remaining emulsion. Was. Thereafter, the temperature was raised to 85 ° C. and an aging reaction was carried out for 2 hours to complete the polymerization reaction, thereby obtaining a medical pressure-sensitive adhesive composition of the present invention.

Example 3 950 g of 2-ethylhexyl acrylate, 20 g of acrylic acid, 100 g of methyl methacrylate,
To a monomer mixture consisting of 0.25 g of trimethylolpropane triacrylate was added 0.5 ml of lauryl mercaptan.
g, 5 g of isopropyl alcohol, and a surfactant (Aqualon HS-2, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
700 g of an aqueous solution containing 1% by weight of 0) was added thereto, emulsified by using a high-speed homomixer (manufactured by Tokushu Kikai Co., Ltd.) under an inert gas atmosphere, and heated to 70 ° C. while stirring was continued.

Then, 1 g of ammonium persulfate as a polymerization initiator was added in an aqueous solution of 15 g of water to start an emulsion polymerization reaction, and the reaction was continued for about 5 hours. Thereafter, the temperature was raised to 85 ° C. and an aging reaction was carried out for 2 hours to complete the polymerization reaction, thereby obtaining a medical pressure-sensitive adhesive composition of the present invention.

Example 4 950 g of 2-ethylhexyl acrylate, 50 g of acrylic acid, lauryl methacrylate 100
g, trimethylolpropane triacrylate 0.25
g in a monomer mixture consisting of 0.5 g of thioglycolic acid.
g, 5 g of isopropyl alcohol, and 700 g of an aqueous solution containing 1% by weight of a surfactant (trade name: Latemul S180A, manufactured by Kao Corporation) was added thereto. Under an inert gas atmosphere, a high-speed homomixer (manufactured by Tokushu Kikai) was added. Then, the mixture was emulsified and heated to 70 ° C. while stirring.

Next, 1 g of potassium persulfate as a polymerization initiator was added in an aqueous solution dissolved in 15 g of water to start an emulsion polymerization reaction, and the reaction was continued for about 5 hours. after that,
The temperature was raised to 85 ° C., and an aging reaction was performed for 2 hours to complete the polymerization reaction, thereby obtaining a medical pressure-sensitive adhesive composition of the present invention.

Comparative Example 1 In Example 1, except that pentaerythritol triacrylate as a polyfunctional monomer was not added, the amount of thioglycolic acid was changed to 3 g, and the amount of n-butyl alcohol was changed to 10 g. In the same manner as in Example 1, a medical pressure-sensitive adhesive composition was produced.

Comparative Example 2 A medical adhesive composition was prepared in the same manner as in Example 1 except that thioglycolic acid and n-butyl alcohol were not blended.

Comparative Example 3 In the same manner as in Example 1, except that pentaerythritol triacrylate as a polyfunctional monomer was not blended and thioglycolic acid as a chain transfer agent was not blended. Thus, a medical pressure-sensitive adhesive composition was prepared.

Comparative Example 4 In Example 1, the compounding amount of lauryl methacrylate was 10 g, the compounding amount of pentaerythritol triacrylate was 1 g, and thioglycolic acid as a chain transfer agent was not used. 10 amount
A medical adhesive composition was prepared in the same manner as in Example 1 except that g was used.

The adhesive composition for medical use obtained in each of the above Examples and Comparative Examples was applied to one side of a polyester film so that the thickness after drying was 40 μm, and dried to prepare an adhesive tape.

For the obtained pressure-sensitive adhesive tape, tack, adhesive strength, holding power, gel fraction, and weight-average molecular weight of the soluble
The measurement was carried out by the following method, and the results are shown in Table 1.

As is clear from the results in Table 1, the tackiness, the adhesive strength and the holding power are good in the product of the example, but the balance is poor in the product of the comparative example. Was also inferior and was not practically satisfactory.

<Tack> 23 ° C., 65% R.C. H. Was measured by the ball rolling method described in JIS Z-0237.

<Adhesive Strength> The adhesive tape was cut into a width of 20 mm, and was cut at 23 ° C. and 65% RH. H. The pressure-sensitive adhesive layer is press-bonded to a bakelite plate at 2 kg / cm ² in an atmosphere of 30 minutes, and after 30 minutes of pressure-bonding, the pressure-sensitive adhesive tape is peeled off at a peeling speed of 300 mm / min by 180 degrees and the peeling stress at that time is bonded. Power.

<Holding Force> The adhesive tape was cut into a width of 20 mm, and one end (20 mm × 10 mm area) of the adhesive tape was pressure-bonded to a bakelite plate at 2 kg / cm ^2. 500 on the other end of the adhesive tape
g was suspended, and the time required for the pressure-sensitive adhesive tape to fall off the bakelate plate due to cohesive failure of the pressure-sensitive adhesive layer was measured.

<Gel Fraction> A predetermined amount of the dried polymer was extracted in toluene at room temperature for 7 days, and the residue (insoluble content = gel content) was extracted with a polytetrafluoroethylene membrane (average pore size: 0.2 μm, Nitto). It was separated by filtration with an NTF membrane (manufactured by Denko Corporation), dried and determined by a gravimetric method, and the weight of the insoluble component relative to the initial weight was calculated as a gel fraction.

<Weight-Average Molecular Weight of Soluble Content> The weight-average molecular weight of the soluble matter in toluene filtered in the above gel fraction measurement was determined by gel permeation chromatography (GPC) in terms of polystyrene. In addition,
For GPC measurement, HLC8120GPC manufactured by TOSOH was used.

[0057]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 20/12 A61L 15/06

Claims (7)

[Claims] An alkyl acrylate having an alkyl group having 4 to 12 carbon atoms, (meth) acrylic acid, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and two or more alkyl methacrylates in a molecule. A medical pressure-sensitive adhesive composition obtained by copolymerizing a monomer mixture containing a polyfunctional monomer having an unsaturated double bond. 2. A monomer mixture comprising 1 to 15 (meth) acrylic acid per 100 parts by weight of alkyl acrylate.
The medical pressure-sensitive adhesive composition according to claim 1, which comprises 2 parts by weight, 2 to 50 parts by weight of an alkyl methacrylate, and 0.001 to 1 part by weight of a polyfunctional monomer. 3. The medical pressure-sensitive adhesive composition according to claim 1, wherein the gel fraction is 40 to 70% by weight. 4. The weight-average molecular weight of the soluble component is from 200,000 to 4
The medical pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the number is 10,000. 5. An alkyl acrylate having an alkyl group having 4 to 12 carbon atoms; (meth) acrylic acid; an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms; Emulsion polymerization of a monomer mixture containing a polyfunctional monomer having a saturated double bond in an aqueous medium in the presence of a chain transfer agent, a hydrophilic alcohol, a surfactant, and a polymerization initiator. For producing a medical pressure-sensitive adhesive composition. 6. 100 parts by weight of alkyl acrylate contains 1 to 15 parts by weight of (meth) acrylic acid, 2 to 50 parts by weight of alkyl methacrylate, and 0.001 to 1 part by weight of polyfunctional monomer. Of the chain transfer agent, 0.001 to 2 parts by weight of the chain transfer agent, 0.0
The method for producing a medical pressure-sensitive adhesive composition according to claim 5, wherein the emulsion polymerization is carried out by adding 01 to 2 parts by weight. 7. A pressure-sensitive adhesive tape or sheet formed by forming the medical pressure-sensitive adhesive composition according to any one of claims 1 to 4 on one surface of a support into a layer having a thickness of 15 to 70 μm.