Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Web – sheet or filament bases; compositions of bandages; or...
Reexamination Certificate
2000-01-07
2001-04-03
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Web, sheet or filament bases; compositions of bandages; or...
C424S448000
Reexamination Certificate
active
06210704
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a medical adhesive dressing used for applying to the skin in the field of medical therapy and hygiene. More particularly, the present invention relates to a medical adhesive dressing used advantageously in a first-aid adhesive tape or a large size adhesive tape, a dressing material, a drape material, etc. The present invention also relates to a first-aid adhesive tape having such a medical adhesive dressing.
2. Description of the Related Art
Medical adhesive dressings usually include a backing film having an adhesive layer on one surface thereof and upon use it is applied to a desired skin surface through the adhesive layer.
The backing films for use in an adhesive dressing for use in medical applications are mostly those which comprise flexible polyvinyl chloride as a main component in view of their skin following property (flexibility) while they are applied to the skin, stretchability (contraction and expansion properties), feeling, etc.
Generally, flexible polyvinyl chloride contains a plasticizer in a large amount in order to impart it with flexibility. It has been pointed out some problems. That is, the plasticizer migrates into the adhesive layer of the adhesive dressing so that its cohesion decreases and the phenomenon of adhesive residue or a decrease in adhesion power occurs. Recently, from the viewpoint of placing importance to environment, movement is being developed in various fields for trying as much as possible to reduce the amount of polyvinyl chloride resins, which contain chlorine, a species of halogen harmful to environment.
Accordingly, polyolefin resins are being given attention as a substitute for polyvinyl chloride resin and study has been made on the usability as the backing film for adhesive dressings for medical use. The backing film made of polyolefin resin is excellent in flexibility and stretchability and is useful as a polyvinyl chloride substituted film.
In the commercialization of such a medical adhesive dressing, it is usually the case that first-aid adhesive tapes or large-size adhesive tapes are manufactured as having a print layer on one surface of the backing film thereof. That is, usually first-aid adhesive tapes and large-size adhesive tapes are devised such that one surface of the backing film is printed by pattern printing in a color resembling human skin. For example, they are provided with patterns of grids, semi-continuous or continuous crosses, etc. so that the adhesive dressing does not attract attention. Products may also be manufactured with multi-color printing.
SUMMARY OF THE INVENTION
However, it has hitherto been difficult to form such a print layer or cutting of film tends to occur when winding or a polyolefin film after the printing in the form of a roll or unwinding it, particularly when the film is thin.
For example, generally, in the case of pattern printing, the film before forming a pressure-sensitive adhesive layer thereon is printed and then a pressure-sensitive adhesive layer is formed. Upon forming a print layer, the backing film needs to be unwound (let out) and if the surface is too smooth, the letting out property is aggravated due to the adhesion between the film surfaces, which sometimes results in the breakage of the film as the case may be. Entrapment of air (bubble) when winding up the film increases the possibility of the occurrence of creases in the backing film. Printing on such creases could cause printing failure, such as lack of print, etc. If the surface a backing film is too smooth, it will be abraded when medical adhesive dressings or first-aid adhesive tapes containing it are in use as applied to the skin. As stated above, in the case of medical adhesive dressings comprising a polyolefin film with a pattern print layer on one surface thereof, it is important to adjust the surface roughness of the film.
When a single-color pattern is applied on a surface of the backing film, generally printing is carried out at a relatively high speed so that minute creases, if any, would result in lack of print. Therefore, the adjustment of the surface roughness of the printing surface is very important.
In case where a multi-color print is applied on a surface of the film, colors are applied one after another in precise registration. Therefore, minute creases if present upon winding the film tends to cause lack of print. In this regard, the adjustment of surface roughness of the printing surface is very important.
As a result of their intensive research, the present inventors have found that the surface conditions of at least one of a polyolefin film as a backing film of an adhesive dressing and a printing layer formed thereon influence winding workability and further printability of the resulting film. They have found that these properties can be improved by adjustment of the surface roughness of the backing film. In other words, the present inventors have found that there is an optimal region for the surface roughness of a film surface.
More specifically, they have found that adjustment of the surface roughness of the surface of the backing film on the side the printing layer to a level within a predetermined range provides a medical adhesive dressing that is excellent in film winding workability and printing layer forming property. Further, they have found that this reduces the abrasion of the printing layer while the adhesive dressing is used. Also, they have found that such adjustment results in excellent workability, gives high quality feeling, and improves slidability upon rubbing against clothes or dresses during the medical adhesive dressing is applied and used.
Therefore, in one aspect, the present invention provides a medical adhesive dressing comprising a polyolefin-based backing film having a medical pressure-sensitive adhesive layer on one surface thereof and a print layer on the other surface thereof, said adhesive dressing having surface properties that cause no wrinkle upon winding and unwinding thereof.
The surface properties of said adhesive dressing may be obtained by adjustment of at least one of property of a surface of the backing film on a side where a print layer is to be formed and property of a surface of the backing film on a side where a pressure-sensitive adhesive layer is to be formed.
The surface of the backing film on the side where a print layer is to be formed preferably has a surface roughness (10-point average roughness) of 2 to 12 &mgr;m.
The surface of the backing film on the side where a pressure-sensitive adhesive layer is to be formed preferably has a surface roughness (10-point average roughness) of 2 to 40 &mgr;m.
Preferably, the surface roughnesses on the both surfaces of the polyolefin-based backing film differ one from the other.
Preferably the surface roughnesses on the both surfaces of the polyolefin-based backing film differ one from the other.
The surface roughness of the surface of the backing film on the side where a pressure-sensitive adhesive layer is to be formed is preferably greater than the surface roughness of the surface of the backing film on the side where a print layer is to be formed.
The polyolefin-based backing film may be one of an ethylene-vinyl acetate copolymer film and a three-layer film comprising an ethylene-methyl methacrylate copolymer layer/A-B-A type block copolymer layer/ethylene methyl methacrylate copolymer layer.
The ethylene-vinyl acetate copolymer may have a vinyl acetate content of 15 to 28% by weight.
The ethylene-vinyl acetate copolymer may have a weight average molecular weight of 1×10
4
to 1×10
5
, a molecular weight distribution of 4 or less, and a melt flow rate of 3 g/10 minutes or less.
The A-B-A type block copolymer may be one of a styrene-butadiene-styrene block copolymer and a styrene-isoprene-styrene block copolymer.
The ethylene-methyl methacrylate copolymer layer may be a layer that contains an ethylene-methyl methacrylate copolymer and low density polyethylene.
The ethylene-methyl methacrylate copolymer layer may c
Kinoshita Takashi
Kousaka Takahiro
Kuniya Masayoshi
Ohira Osamu
Sasaki Yasuyuki
Ghali Isis
Nitto Denko Corporation
Page Thurman K.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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