FR2542201A1 - Medical bandage material - Google Patents

Abstract

Medical bandage material which is extendible in several directions and which is liquid-tight, comprises a layer of polyurethane and a fabric layer which is extendible in all directions, the fabric layer being embedded in the thickness of the polyurethane layer and the fibres in the fabric layer being at least 6 cm long. Pref. the fabric layer is roughly in the centre of the polyurethane layer, the material has a wt. of 20-130 g/m2 andis between 15 and 120 microns thick, and consists of a polyurethane layer with a wt. of 15-80 g/m2 in which a fabric layer of 5-50 g/m2 is embedded. The fabric is esp. of polyolefin, polyester or polyamide fibres or glass fibres. The material pref. has an elongation at rutpure of more than 60% in all directions. The bandage is pref. in the form of an adhesive plaster type dressing with an adhesive applied to the polyurethane layer and a layer of fabric covering at least part of the adhesive layer on the side opposite the polyurethane layer. The free side of the adhesive layer may be covered by at least one anti-adhesion coated protective foil.

Description

New surgical support comprising a polyurethane film and a nonwoven, particularly used in the field of dressings and method of preparation.

 The present invention relates as a novel industrial product to a surgical support comprising a polyurethane film and a nonwoven. It also relates to the use of this support, in particular in the field of adhesive dressings, as well as its method of preparation.

 It is known that it has already advocated in the past the use of polyurethane films in the surgical field, these films being applied as such to protect the operating field. However, it turns out that these polyurethane films, which have good extenability in all directions, have many disadvantages, namely, handling difficulties related to the thinness of said films, which fold back on themselves when separates them from their temporary protective support at the time of use.

 It is also known that in the field of adhesive dressings it has been preferred to use nonwovens which are permeable to water, solvents and body fluids, namely: short staple nonwovens (length of fibers <3 cm) which are not extensible, and non-woven fabrics with long fibers or so-called infinite fibers (fiber length greater than or equal to 6 cm) which are extensible in all directions (as indicated in particular in Belgian Patent No. 857,077).

Now it happens that these nonwovens are not suitable in a large number of cases because of their permeability to liquids.

 According to the invention, a new technical solution is recommended to provide a surgical support, extensible in all directions, resistant, impervious to liquids (such as in particular water, solvents, body fluids) and easily manipulated either for the protection of surgical drapes, that is to say for the production of adhesive bandages.

 According to the invention, therefore, a new surgical support comprising a polyurethane film and a nonwoven, characterized in that it consists of a polyurethane film and an elastically stretchable nonwoven in all directions, embedded in the the thickness of said polyurethane film, the fibers of the nonwoven each having a length greater than or equal to 6 cm.

 The non-woven fabric which is involved in the present surgical support is stretchably stretchable in all directions, in particular length, width and diagonal. It advantageously has a basis weight of between 5 g / m 2 and 50 g / m 2, and is constituted by long fibers or preferably so-called infinite fibers (in general, the fibers of the nonwoven have a length greater than or equal to 6 cm). The nonwoven can be made with synthetic or mineral organic fibers.

 Among the suitable synthetic fibers there may be mentioned thermoplastic organic fibers such as polyalkylene fibers (in particular polyethylene fibers and polypropylene fibers), polyester fibers and polyamide fibers. Advantageously, the nonwoven according to the invention will be prepared melt from the aforementioned thermoplastic fibers, for example, by means of an installation as described in French Patent No. 1,364,916. Such a nonwoven obtained by the molten route and which is commonly called "spun-bonded" by the skilled person, has the advantage of not containing a binding agent capable of reducing the extensibility.

 Among the mineral fibers which are suitable, mention may in particular be made of glass fibers. By way of example, the glass fiber mats of 8 g / m 2 and 10 g / m 2 marketed by the DEXTER company are perfectly suitable.

 The polyurethane films which are advantageously according to the invention are those which have a basis weight of between 15 g / m 2 and 80 g / m 2 and preferably between 20 g / m 2 and 60 g / m 2.

 For the storage and preservation of the surgical support according to the invention, it is recommended to protect at least one side of the polyurethane film by means of a temporary antiadherent support. The temporary support in question can be a synthetic or natural support; for example it may be constituted by a polyalkylene sheet (especially polyethylene or polypropylene) polypropylen @) optionally silicone, or a silicone paper sheet or coated with polyalkylene. At the time of employment temporary protection is removed.

 The surgical support according to the invention is directly usable in the operative fields, it then adheres in particular to the skin because of the difference that exists between the surface tension of said surgical support and that of the skin.

 For the use of the surgical support in the field of adhesive bandages, the free face of the polyurethane film, that is to say one which is not bonded to the temporary protective support mentioned above, is coated with an adhesive mass (advantageously a hypoallergenic or non-allergic adhesive mass, in particular an acrylic adhesive mass), then deposits on at least a portion of the free face of said adhesive mass a textile article, especially chosen from the group consisting of veil, tulle, gauze and compress, temporary protective means being then disposed on the assembly consisting of said adhesive mass and the textile article, the resulting material being finally cut to the dimensions required for the dressings.

The surgical support according to the invention is impermeable to liquids, especially to fuels, solvents and body fluids. It can nevertheless be permeable to gases to ensure a particular comfort when it is used as an adhesive dressing support. In the latter type of use, it is possible to use a gas-permeable adhesive mass. In general, the gas permeability can be obtained according to a method known per se,
especially by microperforation.

The introduction of the non-woven into the thickness
polyurethane film is made according to a known method
in itself. The procedure that lton recommends to prepare the support
according to the invention is characterized in that
comprises
10) the deposit on a temporary antiadherent support,
by coating, of a chosen liquid composition
among the set consisting of the solutions and
polyurethane suspensions in a suitable medium,
20) the introduction of the nonwoven into the composition
liquid deposited on the temporary anti
adherent by means of a cylinder likely to plunge
in said liquid composition, and
30) drying the coated mass comprising in situ
the non-woven, then, if necessary, the elimination of
temporary anti-adhesive coating support.

At step 10) above the polyurethane is
in particular deposited on the temporary support or in solution
in a suitable solvent such as in particular dimethylformamide
(DMF), tetrahydrofuran (THF) and DMF-methyl mixtures
ethyl ketone, either in emulsion in water comprising at least
a surfactant, especially the stearate of an alkali metal
such as sodium or potassium.

If appropriate, the solution or emulsion
polyurethane of stage la) can contain a dye or pigment essentially for an aesthetic appearance of the final product.

Advantageously the concentration of
polyurethane in the liquid medium is included
between 20 and 50 g / l.

The introduction of the non-woven in situ
at stage 2) can be achieved by means of a dipping cylinder
in the liquid composition that has been deposited on the support
temporary and guiding said nonwoven, as shown in the
figure 3 below. The introduction of the nonwoven in situ can also be achieved by gravity, the cylinder guiding the nonwoven being then disposed in the vicinity and above the composition which has been coated, as shown in the single figure of the application for published patent EP-A1-49177.

 Drying of stage 30) is carried out at a temperature permitting the evaporation of the solvent or the water of the emulsion. The whole of the stages le) to 30) makes it possible to obtain a dry material, namely a surgical support, constituted by a polyurethane film enclosing in situ a nonwoven, extensible in all directions (machine direction, cross-direction, diagonal direction) and preferably having a grammage of between 20 and 130 g / m 2 (weight of 15 to 80 g / m 2 for the polyurethane film, and basis weight of 5 to 50 g / m 2 for the non-woven fabric) and a thickness of between advantageously 15 and 120 / A '. Such a surgical support has an elongation at break always greater than 60% in all directions.

 If desired, it is possible to obtain a grammage greater than 130 g / m2 and a thickness greater than 120 t, or even greater than 150, but such surgical supports are not specifically necessary if the supports having a basis weight of 20 to 130 g / m2 and a thickness of 15 to 120 cm9 have a suitable extensibility and in particular greater than that of the skin of children and adults.

 Other advantages and features of the invention will be better understood on reading the following examples of embodiments and the description of the accompanying drawings.

These examples and drawings, which are not limiting, are given by way of illustration. In these drawings, FIG. 1 represents a perspective view of a support
surgical device according to the invention consisting of a poly film
urethane 1 containing in situ a nonwoven 2, this support
surgical device further comprising a temporary anti
adherent 3 (polyalkylene sheet or silicone paper sheet)
which may have an anti-adhesive layer on its side 4; FIG. 2 represents a perspective view of a dressing
adhesive obtained from the surgical support according to
the invention and which comprises the film 1 in which is embedded
the nonwoven 2, the temporary support 3 as indicated above
and may have an anti-adhesive layer on its face 4,
on the one hand, a hypoallergenic acrylic adhesive mass 5
of which at least part of the face that is not in contact
with the film I is provided with a textile article 6, the whole
adhesive mass 5 - textile 6 can be coated by a means
temporary anti-blocking protector (not shown here),
in particular two protective wings removable at
the time of placement of the dressing, on the other hand, - Figure 3 shows schematically an installation allows
both to obtain a surgical support according to the invention, - Figures 4 and 5 illustrate the variation of the resistance to the
RT traction expressed in daN / cm (ordinate) according to
the elongation L expressed in% (in abscissas) to compare different
surgical supports according to the invention, to poly films
urethane and a nonwoven.

 According to FIG. 3, an emulsion or suspension of polyurethane 11 is deposited by coating on a temporary antiadhesive support 3 whose face 4 is silicone coming from a cylinder 10. The quantity of emulsion or suspension of polyurethane deposited on the temporary support 3 is adjusted by the opening between the blade 17 and the cylinder 16.

The non-woven? which comes from the cylinder 12 is introduced into the mass coated by means of the cylinder 15 immersed in the emulsion or suspension of polyurethane. After passing through the drying tunnel 13, the material represented in FIG. 1 is collected by means of the cylinder 14.

EXAMPLE 1
On a non-sticking temporary support constituted by a polyethylene sheet having a silicone face, an aqueous emulsion containing 40 parts by dry weight of polyurethane, 60 parts by weight of water and 0> 05 is deposited on the non-silicone side by coating. to 0.1 part by dry weight of surfactant (potassium stearate) and having a pH of 8.5. The coating is carried out in such a way that the amount of deposited aqueous emulsion can give after drying a polyurethane film having a basis weight of 25 g / m 2.

 Immediately after coating is introduced in situ (as illustrated in Figure 3) in the still fluid coated mass, a non-woven of 10 gjm2 consisting of infinite fibers of polypropylene (marketed under the name "LUTRASIL 5010" by the company LUTRAVIL ).

 After passing through the drying tunnel, a dry material is obtained according to FIG. 1, in which the surgical support consisting of the polyurethane film and the non-woven fabric in situ has a basis weight of 35 g / m 2 and a thickness of approximately 40. . This surgical support adheres only very slightly to the non-silicone side of the temporary support and can be separated from said support without difficulty and without being tampered with. The silicone face enables the material of FIG. 1 to be wound on itself.

 The mechanical properties of this surgical support are as follows - longitudinal tensile strength 0.7 daNtem, - elongation at longitudinal fracture 90%, - resistance to transverse fracture 0.6 daN / cm, - elongation at transverse fracture 80 %.

 The extensibility curve (tensile strength as a function of elongation) of the surgical support of Example I is given in FIG. 5 (see curve F).

EXAMPLES 2 to 4
By proceeding as indicated in Example 1, but producing a coating giving a polyurethane film having a basis weight of 35 g / m 2, 50 g / m 2 and 60 g / m 2 respectively, the same nonwoven of said example is obtained. 1, surgical supports having a basis weight of 45 g / m 2 (Example 2), 60 g / m 2 (Example 3) and 70 g / m 2, respectively (Example 4).

 The extensibility curves of these supports are given in FIGS. 4 and 5 (see curves G, D and respectively E).

EXAMPLE 5
The surgical support of Example 1 provided with its temporary protective sheet used for the coating is subjected to a coating by means of the polyurethane emulsion (polyethylene sheet having a silicone face) to deposit a hypoallergenic acrylic adhesive mass. This coating can be performed on the same loom that has been used to obtain the surgical support. Deposition of the adhesive mass is performed on the face of the surgical support not bound to the temporary protection sheet. After drying of the resulting material, the free face of the adhesive mass is protected by a temporary protective means, of the type comprising, for example, two protective fins. The desired dimensions are then discouraged for the dressings that can be packaged in an envelope which is free elimination of the first temporary support.

EXFM> LE 6
By proceeding as indicated in Example 1 but replacing the infinite polypropylene fiber nonwoven with a mat of glass fibers of 8 g / cm 2 in which the glass fibers have a length greater than or equal to 6 cm, a surgical support having an elongation at break greater than 80% is obtained.

COMPARATIVE TESTS I
For comparison, the extensibility of the 60 g / m 2 surgical support made of a 50 g / m 2 polyurethane film containing in situ a nonwoven (infinite polypropylene fibers) of 10 g / cm 2 was studied for comparison. m2 with the extensibility of said polyurethane film and that of the nonwoven. The results are given in FIG. 4 where the curves represent the variation of the tensile strength RT in daN / cm as a function of the elongation L in%, measured on samples of 2 cm by 10 cm.

 Curve A is that of the nonwoven alone, curve B that of the polyurethane film alone, curve C represents the sum of curves B and C, and curve D is that of the surgical support of example 3.

FIG. 4 shows, surprisingly, that the surgical support according to the invention has a higher tensile strength than that of the nonwoven, that of the polyurethane film and that which would result from the simple addition of the nonwoven and polyurethane, the elongation at break of the surgical support of Example 3 being greater than 90%
COMPARATIVE TRIALS
Comparative tests were carried out to assess the extensibility of the surgical supports of Examples 1, 2 and 4 with respect to a film of 60 g / m 2 of polyurethane alone. The results given in FIG. 5 show that the products of examples 1 (curve F), 2 (curve G) and 4 (curve H) have better tensile strengths than said polyurethane film alone (curve E).

 It can be seen from comparative tests I and II that the surgical supports according to the invention have an elongation at break always greater than 60% and that consequently they are perfectly suitable for application to the skin following the movements thereof. Indeed, in man the elongation at break of the skin is always less than 60 ie 24 to 48 Z in adults and 37 to 52% in the child.

Claims (5)

1. A liquid-impervious, expandable, all-directional surgical support comprising a polyurethane film and a nonwoven, said support being characterized in that it consists of a polyurethane film and an elastically stretchable nonwoven in all directions, embedded in the thickness of said polyurethane film, the fibers of the nonwoven each having a length greater than or equal to 6 cm. 2. Surgical support according to claim 1 characterized in that it has a basis weight between 20 and 130 g / m2 and a thickness of between 15 and 120 F 7 and in that it consists of a polyurethane film having a weight of 15 to 80 g / m 2 which comprises in situ a nonwoven having a basis weight of 5 to 50 g / m 2. 3. Surgical support according to any one of claims 1 and 2 characterized in that the nonwoven is constituted by fibers selected from the group consisting of polyalkylbne fibers, polyester, polyamide and glass. 4. Surgical support according to any one of claims 1 and 2, characterized in that its elongation at break is greater than 60% in all directions.  5. Process for the preparation of a surgical support according to any one of claims 1 to 4, characterized in that it comprises  10) the deposit on a temporary antiadhesive support, by  coating, of a liquid composition selected from  appears to be the solutions and suspensions of  polyurethane in a suitable medium,  2) the introduction of the nonwoven into the liquid composition  deposited on the temporary anti-adhesive medium  a cylinder capable of diving into said composition  liquid, and  30) drying the coated mass comprising in situ the non  woven, then, if necessary, the elimination of the support  temporary. 6. The process as claimed in claim 5, characterized in that the suitable coating medium is a solvent chosen from the group consisting of dimethylformamide (DMF), tetrahydrofuran (THF) and DMF-methylethylketone mixtures. . 7, Process according to claim 5, characterized in that the liquid coating composition is an aqueous suspension containing the polyurethane and a surfactant. 8. Use of the surgical support according to any one of claims 1 to 4 in the field of dressings, characterized in that said surgical support comprises on one of its faces an adhesive mass, in particular deposited by coating, a textile article being deposited on at least a portion of the free face of said adhesive mass.