WO2012050448A1

WO2012050448A1 - Method for producing a cohesive surgical dressing

Info

Publication number: WO2012050448A1
Application number: PCT/NL2011/050700
Authority: WO
Inventors: Ron Houwlo
Original assignee: Emrcare B.V.
Priority date: 2010-10-14
Filing date: 2011-10-14
Publication date: 2012-04-19
Also published as: NL2005513C2

Abstract

Method for producing a self-adhesive surgical dressing. The surgical dressing consists of a rubber provided with a protective layer which has to be removed before use. The rubber material adheres to itself and not to the skin. Such a surgical dressing can be obtained according to the invention by starting from rubber provided with a cover layer. A sheet of such rubber can be cut into strips having the final width and, upon the removal of the protective layer, a sulphur- containing paper can be applied to the strip and the strip can subsequently be brought into the shape of the pack. According to the invention, this pack is heated for at least 1 hour to at least 40 degrees, during which heating the parts of the pack are pressed together, whereby the sulphur, in the protective layer, reacts with the rubber and thus the desired properties are obtained.

Description

METHOD FOR PRODUCING A COHESIVE SURGICAL DRESSING

The present invention relates to a method for producing a surgical dressing. More particularly, the present invention relates to a surgical dressing consisting of a material which adheres to itself, such as a rubber material which is self- vulcanizing. This is supplied in a packaging to the user, the surgical dressing having been wound, folded in a zigzag or consisting of stacked surgical dressings. For the purpose of avoiding premature adherence, the surgical dressing is provided on one side or both sides with a protective layer. The properties of the surgical dressing are such that, when it is applied to the skin, no or negligible adhesion with the skin, hairs or other tissue takes place, whilst, when two parts of surgical dressing are applied to each other, a mutual connection takes place, so that an elastic, fully enclosing whole is formed.

The product which is available on the market has relatively poor properties, particularly with regard to adhesion and elasticity.

US 2 082 599 discloses a surgical dressing, in which vulcanized latex is used.

US 3 697 315 likewise describes a surgical dressing, in which synthetic rubber latex, whether or not in combination with natural rubber latex, is used.

An object of the present invention is to provide a method in which a very elastic surgical dressing is realized, which surgical dressing, when the material is pressed together, provides adhesion particularly quickly.

This object is achieved in an above-described method by virtue of the fact that this method comprises:

providing a precursor sheet,

applying sulphur-containing sheets to both sides of that precursor sheet, resulting in a pack;

heating of the resultant pack for at least 1 hour at at least 40°C and/or supplying radiation energy to the pack, and

packaging of the resulting product.

In particular, the parts of the above-described pack are pressed together during the heating.

By "pack" is here meant the acquired result of the application of sulphur- containing sheets on both sides of that precursor sheet, i.e. the layered structure consisting of at least the precursor sheet and the surrounding sulphur-containing sheets. By this are understood both the unfolded layered structure and the configurations which can be obtained therefrom, following, for example, roll-up, cutting, punching, etc. Customary configurations of the pack are, for example, a circular, rolled-up pack, a rolled-up flattened pack, or a zigzag-folded pack.

According to the present invention, heating takes place for a relatively long time. It has been shown that sulphur from the sulphur-containing sheet is then optimally capable of reacting with the rubber material, so that a self-adhesive (self- vulcanizing) rubber material is formed. It has further been shown that, through the relatively long heating at the above-stated temperature, the relatively thin material can be subjected to the method without risk of breakage upon subsequent use, by virtue of the particularly good elastic properties obtained with the method according to the present invention. The combination of time and temperature determines the effect of the invention. That is to say, if the time chosen is relatively short, such as 1 hour, the temperature should be relatively high, for example 75 °C or more, and vice versa. Thermal energy can also be supplied to the pack in other ways, for example by means of electromagnetic radiation. It has been found that, through the supply of radiation energy to the pack, for example in the case of a pack placed in a microwave resonant cavity, or, for example, through irradiation with an infrared lamp, a comparable self- adhesive surgical dressing product can be obtained. Precise values for the power and radiation period of the radiation source depend on various factors, such as the wavelength and the actual radiated power of the radiation source, the thickness of the surgical dressing, and the final shape of the pack. According to one embodiment, a non- rolled-up pack having a thickness of around 0.5 - 1 mm, for example, can be irradiated in a conventional magnetron at a power of 800W for a minimum of 20 seconds, for example 30 seconds (equal to 24 kJ). At lower magnetron powers, it has been shown that the procurement of adequate self-adhesiveness of the surgical dressing product requires a non-linear extension of the radiation time, so that, for example at a magnetron power of 90W, a radiation time of a minimum of 5 min. (thus 27kJ) is required.

More particularly, the base material has a maximum thickness of 3 mm and is more particularly about 0.8 mm thick.

According to an advantageous embodiment of the present invention, the rubber material comprises natural rubber. More particularly, the rubber material comprises sterilized rubber. Proteins which give rise to allergenic reactions can thereby be rendered harmless. If such types of material are used, no (allergic) reaction of the human body is likely. As an alternative, the rubber material comprises synthetic rubber, so that the chemical composition can be adapted according to requirements. More particularly, the rubber comprises crepe rubber.

The precursor sheets are preferably supplied as a stack, the sheets being mutually separated by cover layers. According to one particular embodiment of the present invention, each precursor sheet is cut into a number of strips, the strips conforming to the product which is ultimately to be sold or the quantity of the products to be sold. As an example is cited a precursor sheet of lxl m size, with the strips having a width, for example, of about 6 cm.

Following the removal of the cover layers, these are replaced by protective layers having the composition which shall be described below. The width of these protective layers can be equal to the above-described width of the rubber strips, but in a preferred embodiment is somewhat wider. In the surgical dressing, the protrusion on both sides with respect to the precursor sheet allows a freely protruding part of the protective layer to be easily grasped by the user for the removal thereof.

According to one particular embodiment of the present invention, such strips are wound upon themselves to form a pack. This winding can be realized by rolling, but it is also possible to fold the aforementioned strips one upon the other in a zigzag pattern. In the winding operation, the above-described protective layer or layers is/are applied between the sheet material. Of course, any cover layer which was present has previously been removed from the precursor sheet. It is possible to apply a protective layer equally on one side or on both sides of the precursor sheet. It is likewise possible to work without the use of a pack.

The protective layer preferably consists of grease-free paper, such as baking paper known in the prior art, also denoted as sulphate paper. As a particular example thereof, Sulpac Sulfurise is cited.

It will be recognized that other sulphate-containing or sulphur-containing protective layers can be used. As an example, a square metre weight of 30-50 g is cited, and more particularly the weight of the protective layer is about 45 g/m . At the same time, it has been found that the use of other non-adhesive paper types as protective sheets during heating can also lead to the desired self-adhesiveness of the surgical dressing product, provided that the protective sheet can withstand the specified heating temperature and has sufficient surface smoothness to prevent absorption of the rubber from the precursor sheet into the protective sheet. Examples of practicable protective sheets of this kind are, for example, cellulose-based (and possibly fibre-reinforced) paper types, provided with a silicone and/or latex rubber impregnation or cover layer. Such other paper types can have a different mass density from that which has been stated above, for example around 120 g/m².

As described above or according to a further advantageous embodiment, the parts of the above-described pack are pressed together during the heating. This can be realized on any kind of clamping means, such as a clamping band. Moreover, a number of packs as described above are stacked one upon the other during the heating. All of these measures serve for the pressing together of the protective layer and the rubber material. A (low) adhesion between the protective layer and the rubber material is thereby obtained and, moreover, sulphur in the protective layers can be absorbed into the rubber.

As indicated above, the combination of time and temperature determines the quality of the product. A higher temperature is accompanied by a shorter time, and vice versa. The heating takes place preferably between 60 and 75° for preferably 10-12 hours. Heating can take place in any manner which is conceivable in the prior art. As examples, radiation (also magnetron) and the like are cited. Preferably, heating takes place by air heating.

The precursor sheet preferably has a structure, for example a ribbed, crepe structure or structure having other irregularities, whilst the final surgical dressing is smoother.

Following the above-described heat treatment, the product, whether or not it has been shortened and rewound, can be packed, e.g. in a box.

The invention will be illustrated in greater detail with reference to an illustrative embodiment, wherein:

Fig. 1 shows the precursor sheet in perspective;

Fig. 2 shows a strip cut from the precursor sheet;

Fig. 3 shows a pack;

Fig. 4 shows the pack according to Fig. 3 provided with a clamping band;

Fig. 5 shows a number of packs in a heating cabinet; Fig. 6 shows the packaging of the product into a box; and

Fig. 7 shows in schematic representation the application of the product according to the invention to the thumb of a human.

In Fig. 1, a precursor sheet is denoted by 10. This consists of sterile rubber material, the surface of which has an irregular structure. One example of a structured precursor sheet of this type is a crepe structure. This precursor sheet 10 has a thickness between 0.5 and 2 mm and in the present illustrative embodiment is about 0.8 mm thick. On both sides thereof, a cover layer 11 is applied.

During the first step of the present invention, the sheet 10 shown in Fig. 1 is cut with cover layers 1 1 into strips 12, as shown in Fig. 2. As an example of the strip shown in Fig. 2, a length of about one metre and a width of about 6 centimetres is cited.

Subsequently, the cover layers 11 are removed from the precursor sheet 10 and on both sides thereof is applied a strip having a protective layer 13. This strip 13 has a width of, for example, 7 cm and length consistent with the length of the strip 12 shown in Fig. 2. This protective layer consists of sulphate paper, such as the abovementioned Sulpac Sulfurise, having a weight of about 45 g/m². In Fig. 3, it is shown that a pack 15 is obtained by winding up the combination of protective layer 13 and precursor sheet 10. It is likewise possible to stack the latter in a zigzag shape.

The resultant pack 15 is brought under compressive stress by the application of a clamping band 14. This is shown in Fig. 4.

In Fig. 5 is shown an air heating cabinet 16, in which a temperature of 40- 100°C, and more particularly about 60-75°C, can be maintained. In this heating cabinet 16, a number of packs 15 are placed one above the other. Subsequently, heating takes place for at least 9 hours, and more particularly 10-12 hours. It will be recognized that the heating time can both be extended to at least 20 hours and shortened to at least 1 hour. It will be recognized that, if the heating cabinet is sufficiently large, it is not necessary to provide packs. The precursor sheet, limited on both sides by protective layers 13, can be stacked with other precursor sheets having protective layers. Moreover, preloading of the protective layer on the rubber material can be obtained, apart from by the clamping band 14, by the weight of the above-lying sheets of material or by an extra weight. The sequence of the stacking is possibly changed during the heating.

It has been shown that the sulphur present in the protective layer 13 reacts with the rubber and thus changes the properties thereof. On the one hand, a surgical dressing 9, whose parts lying one upon the other (upon the removal of the protective layers 13) adhere particularly quickly and well, is obtained. Moreover, considerable elongation thereof is possible without breaking. As a result of the relatively low thickness, such elongation can be realized easily by the user without fear of local constriction and consequent fracture.

In Fig. 6, the packaging of the pack 15 following treatment in the cabinet 16 is shown. It is possible to adapt the manner of winding, as can be seen, for comparison purposes, from Fig. 3/4 and Fig. 6. In Fig. 3, the latter has been wound in a spiral, whilst in Fig. 6, there is a zigzag shape. In addition, shortening can take place.

As an example of a packaging, a box 7 is shown. If the sheet or the strip 12 is shortened, a sheet part or strip parts is/are formed, denoted by 5 in Fig. 6.

In Fig. 7 is shown a thumb 6, around which such a sheet part 5 is wound following the removal of the protective layers 13.

With the present invention, it is possible to obtain a particularly homogeneously elastic product, which can be applied with little effort and, as a result of the high elasticity, adapts closely to the body part to which or around which this is applied. The fact that it does not adhere to the skin or other tissue means that removal is painless, whilst, as a result of the ends of the surgical dressing 9 being stuck together, a quick, stable adhesion is obtained, so that, for example, in the case of still bleeding wounds, permanent coverage can immediately be obtained. The surgical dressing according to the present invention has numerous applications for all kinds of bleeding wounds, burns, grazes and the like. Furthermore, the surgical dressing is waterproof and the adhering attachment is water resistant. Moreover, the surgical dressing, by virtue of the small thickness, is air-permeable, which, on the one hand, minimally limits the user in his actions and, on the other hand, promotes the healing process. Apart from the above- described use, in which direct contact with human, animal or vegetable tissue takes place, it is also possible to fix another underlying dressing with the surgical dressing according to the present invention and to protect it against attack by fluids and dirt.

Following the above, variants which lie within the scope of the present invention will immediately occur to persons skilled in the art. The protective scope is defined by the attached claims. In addition, rights are expressly requested for the subclaims independently from the subject matter of the main claim.

Claims

Method for producing a surgical dressing (9), which surgical dressing comprises rubber material which adheres to itself and not to the human skin,

comprising the combining of that surgical dressing with a protective layer, which method comprises:

providing a precursor sheet (10),

applying sulphur-containing sheets (13) on both sides of that precursor sheet, resulting in a pack (15);

heating of the resultant pack (15) for at least 1 hour at at least 40°C and/or supplying radiation energy to the pack, the sulphur-containing sheets (13) and the precursor sheet (10) of the pack (15) being pressed together during the heating, and

packaging of the resulting product.

Method according to Claim 1, wherein the rubber material comprises natural rubber.

Method according to one of the preceding claims, wherein that rubber material comprises sterile and/or synthetic rubber.

Method according to one of the preceding claims, wherein that rubber material has a maximum thickness of 3 mm and preferably 0.8 mm.

Method according to one of the preceding claims, wherein the provision of stacked precursor sheets (10) comprises the provision of stacked precursor sheets, a cover layer (11) being present between the sheets, which cover layer is removed from the precursor sheets (10) before the addition of the sulphur- containing layer (13).

Method according to one of the preceding claims, wherein the precursor sheets, before the addition of the sulphur-containing sheets (13), are cut into strips (12), and the sulphur-containing sheets have a shape corresponding with these strips.

7. Method according to one of the preceding claims, wherein the shaping of a pack of that precursor sheet comprises the pressing together of adjoining sheet parts (5).

8. Method according to claim 7, wherein the pressing together of the sheet parts is realized by the application of clamping means (14) around a pack (15).

9. Method according to one of the preceding claims, wherein a number of packs are stacked one upon the other in the heating operation.

10. Method according to one of the preceding claims, wherein the heating takes place at 60-75°C.

1 1. Method according to one of the preceding claims, wherein the heating takes place for 10-12 hours.

12. Method according to one of the preceding claims, wherein that sulphur- containing sheet is a grease-free paper sheet.

13. Method according to one of the preceding claims, wherein that sulphur- containing sheet has a weight of 30-50 gram/m².

14. Method according to one of the preceding claims, wherein that precursor sheet has a ribbed structure and the surgical dressing is substantially smooth.

15. Pack (15), comprising a precursor sheet (10) and sulphur-containing sheets (13) applied on both sides of that precursor sheet, obtained with the method according to one of the preceding claims.