Medical pressure-sensitive adhesive composition, process for producing the same, and medical tape

Abstract

A medical pressure-sensitive adhesive composition having excellent re-adhesion property, and also excellence in both the peel adhesion property and the low skin stimulus property, a process for producing the same, and a medical tape are provided. In the medical tape, a medical pressure-sensitive adhesive composition containing acrylic polymer and acrylic oligomer is laminated on a substrate, wherein the medical pressure-sensitive adhesive composition is prepared by cross-linking an intermediate composition containing an acrylic polymer having a cross-linkable functional group and an acrylic oligomer containing 10 to 40 percent by mole of vinyl monomer with a lactam ring through the use of a cross-linking agent, and wherein this medical tape is made by compounding the acrylic oligomer in the range of 50 to 700 parts by weight relative to 100 parts by weight of acrylic polymer, while the number average molecular weight of the acrylic polymer is set at a value within the range of 300,000 to 1,500,000, and the number average molecular weight of the acrylic oligomer is set at a value within the range of 1,000 to 10,000.

Description

TECHNICAL FIELD The present invention relate to a medical pressure-sensitive adhesive composition, a process for producing the same, and a medical tape (adhesive tape). In particular, it relates to a medical pressure-sensitive adhesive composition having excellent re-adhesion property, and also excellence in both the peel adhesion property and the low skin stimulus property (low skin irritation), although the two are mutually contradictory. Also it relates to a process for producing the same, and a medical tape. BACKGROUND ART Since a medical tape (adhesive tape) which consists of a substrate and a medical pressure-sensitive adhesive composition is used by adhering or winding itself around the skin (corneous layer), as well as having moderate adhesion to the skin; it is preferable to have a proper peel property that does not cause skin stimulus or a rash by peeling damage to the corneous layer of the skin. Therefore, in recent years, the medical pressure-sensitive adhesive compos...

AI Technical Summary

Benefits of technology

That is, since a specific acrylic oligomer increases the wetting area against the skin, the predetermined peel adhesion strength can be obtained, while a medical pressure-sensitive adhesive composition exhibiting low skin stimulus and having an excellent re-adhesion property can be obtained. Moreover, since the number average molecular weight of the acrylic polymer to be used is comparatively high, and the acrylic polymer is cross-linked, a high cohesive force is obtained, a good compatibility with an acrylic oligomer is exhibited, peel adhesion strength is easily obtained, and the migration of the acrylic oligomer to the outside from the acrylic polymer can be prevented easily. [2] Also, in the component of the medical pressure-sensitive adhesive composition of the present invention, it is preferable that an acrylic polymer having no cross-linkable functional group is included other than the acrylic polymer having a cross-linkable functional group, and the additional amount of this acrylic polymer is set at a value within the range of 1 to 50 percent by weight, relative to the whole amount of the medical pressure-sensitive adhesive composition. [3] Also, in the component of the medical pressure-sensitive adhesive composition of the present invention, it is preferable that the acrylic oligomer contains a (meth)acrylic acid alkyl ester monomer as a monomer component, and the molar fraction of this (meth)acrylic acid alkyl ester monomer is set at a value within the range of 60 to 90 percent by mole relative to the whole amount of the oligomer. [4] Also, in the medical pressure-sensitive adhesive composition of the present invention, it is preferable that the acrylic oligomer includes 2-ethylhexylacrylic ester and N-vinyl-2-pyrrolidone as monomer components. [5] Also, in the medical pressure-sensitive adhesive composition of the present invention, it is preferable to set the viscosity (25° C.) of the acrylics oligomer at a value within the range of 10 to 1,000 dPa·. [6] Also, in the component of the medical pressure-sensitive adhesive composition of the present invention, it is preferable that a medicament is included at content within the range of 0.1 to 30 percent by weight relative to the whole amount of medical pressure-sensitive adhesive composition. [7] Moreover, an another embodiment of the present invention is a process for producing a medical pressure-sensitive adhesive composition including the following steps (1) to (4); (1) a step to prepare an acrylic polymer that has a number average molecular weight of 300,000 to 1,500,000 and has a cross-linkable functional group (2) a step to prepare an acrylics oligomer which has a number average molecular weight of 1,000 to 10,000 and in which monomer components containing 10 to 40 percent by mole of vinyl monomer with a lactam ring are polymerized (3) a step to prepare an intermediate composition by compounding an acrylic oligomer within the range of 50 to 700 parts by weight relative to 100 parts by weight of acrylic polymer (4) a step to add a cross-linking agent into the intermediate composition obtained from the step (3) so as to carry out the cross-linking

Thus, by carrying out the production process in this way, the wetting area increases against the skin and a predetermined peel adhesion strength is obtained, while a medical pressure-sensitive adhesive composition exhibiting low skin stimulus and having an excellent re-adhesion property is obtained efficiently, since the mixing and dispersion of the acrylic polymer and the acrylic oligomer becomes easy and uniformly. [8] Also, an another embodiment of the present invention is a medical tape in which a medical pressure-sensitive adhesive composition is laminated on a substrate, wherein the medical pressure-sensitive adhesive composition is prepared by cross-linking an intermediate composition containing an acrylic polymer having a cross-linkable functional group and an acrylic oligomer prepared by polymerization of monomers containing 10 to 40 percent by mole of vinyl monomer with a lactam ring through the use of a cross-linking agent. This medical tape is made by compounding the acrylic oligomer in the range of 50 to 700 parts by weight relative to 100 parts by weight of acrylic polymer, while the number average molecular weight of the acrylic polymer is set at a value within the range of 300,000 to 1,500,000, and the number average molecular weight of the acrylic oligomer is set at a value within the range of 1,000 to 10,000.

By constituting the medical tape like this, an excellent wettability against the skin is exhibited, a predetermined peel adhesion strength is obtained, while the skin stimulus is low, and an excellent re-adhesion property is exhibited. Furthermore, since it is easy to relatively adjust the peel adhesion strength and the cohesive force, the transfer of the acrylic oligomer to the backside of the substrate can be easily prevented.

Problems solved by technology

However, each of the external application medicine component has been disclosed in JP6-4533B and JP3-70685B is substantially a single formulation, and moreover, because it is not cross-linked, it causes a shortfall of cohesive force or an excessive restriction of the additional amount of an acrylic oligomer, and the control of the corneous picking area ratio becomes difficult.

Moreover, since the number average molecular weight of the acrylics polymer to be used is low, the problem is witnessed in that the cohesive force becomes even more insufficient and the adhesion to the skin becomes poor.

More concretely, since the compatibility between the acrylic polymer and the liquid component or a plasticizer that is added to the acrylic polymer is inadequate, the liquid component may migrate to the surface of the adhesion layer, and skin stimulus becomes high.

On the other hand, the problem is witnessed in that proper peel adhesion strength is not obtained when the adhesion is tried again, after adhesion to the skin and peeling off have once been performed.

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