Elastic bandage having improved compression properties

Abstract

A compression bandage that is formed by the assembling of a self-adhesive nonwoven based on short conjugate fibers which have been crimped and of an elastic material, the effectiveness of which increases over time. The bandage can be used, alone or in a bilayer compression system, for the prevention or treatment of venous pathologies or lymphedema.

Claims

1. A compression bandage comprising an elastic material and a nonwoven of crimped fibers obtained from short conjugate fibers, said elastic material and said nonwoven being assembled together, said nonwoven having a grammage of between 70 g/m.sup.2 and 300 g/m.sup.2, said crimped fibers being uniformly crimped in a thickness direction of the nonwoven, and exhibiting a mean curvature radius between 10 and 200 micrometers, and a surface of the nonwoven having between 10 and 50 crimped fibers/cm.sup.2.

2. The compression bandage as claimed in claim 1, wherein the short conjugate fibers are bicomponent fibers that are made of two polymer components which exhibit a softening point greater than or equal to 100 C., and which are selected from the group consisting of polypropylene polymers, polyester polymers and polyamide polymers.

3. The compression bandage as claimed in claim 2, wherein the bicomponent fibers are composed of a first polymer which is a polyethylene terephthalate and of a second polymer which is a copolymer of an alkylene arylate with isophthalic acid and/or diethylene glycol.

4. The compression bandage as claimed in claim 2, wherein the two polymer components consist of two different aromatic polyester polymers.

5. The compression bandage as claimed in claim 1, wherein the short conjugate fibers have a mean count between 1 and 5 dtex, and a mean length between 10 and 100 mm.

6. The compression bandage as claimed in claim 1, wherein the crimped fibers exhibit a mean curvature radius between 50 and 160 micrometers.

7. The compression bandage as claimed in claim 1, wherein the nonwoven has a grammage of between 80 and 200 g/m.sup.2.

8. The compression bandage as claimed in claim 1, wherein the surface of the nonwoven has between 10 and 35 crimped fibers/cm.sup.2.

9. The compression bandage as claimed in claim 1, wherein the nonwoven exhibits, in a cross-section taken parallel to the thickness direction thereof, a fiber incurvation ratio greater than or equal to 1.3, and a ratio between a minimum value of the fiber incurvation ratio and a maximum value of the fiber incurvation ratio greater than 75%, wherein said ratio and said fiber incurvation ratio are measured in three parts of the nonwoven, each part corresponding to one third thereof in a cross-section taken perpendicular to the thickness direction of the nonwoven.

10. The compression bandage as claimed in claim 1, wherein the elastic material and the nonwoven are needled and in that the compression bandage exhibits a peel strength at 180 on itself of between 0.02 and 0.5 N/cm.

11. The compression bandage as claimed in claim 1, wherein the elastic material and the nonwoven are needled and a surface of the elastic material exhibits, after assembling, a dynamic friction coefficient of between 2 and 4.

12. The compression bandage as claimed in claim 11, wherein the elastic material is a hydrophobic or hydrophilic foam, or a 3D knitwear.

13. The compression bandage as claimed in claim 11, wherein the elastic material is a hydrophilic polyurethane foam.

14. The compression bandage as claimed in claim 1, wherein the elastic material is chosen from textile materials, cellular materials, films or their combinations.

15. The compression bandage as claimed in claim 1, wherein the nonwoven and the elastic material are assembled by needling, with an adhesive or by ultrasound.

16. The compression bandage as claimed in claim 1, wherein the nonwoven is composed of bicomponent fibers based on aromatic polyester polymers, the nonwoven has a grammage of between 90 and 150 g/m.sup.2 and the surface of the nonwoven has between 10 and 35 crimped fibers/cm.sup.2.

17. The use of a compression bandage as claimed in claim 1 comprising applying the compression bandage to a limb of a patient.

18. The compression bandage as claimed in claim 1, wherein the short conjugate fibers have a mean count between 1.5 and 3 dtex, and a mean length between 40 and 60 mm.

19. The compression bandage as claimed in claim 1, wherein the crimped fibers exhibit a mean curvature radius of between 70 and 130 micrometers.

20. The compression bandage as claimed in claim 1, wherein the nonwoven has a grammage of between 90 and 150 g/m.sup.2.

21. The compression bandage as claimed in claim 1, wherein the elastic material and the nonwoven are needled and in that the compression bandage exhibits a peel strength at 180 on itself of between 0.025 and 0.05 N/cm.

22. The compression bandage as claimed in claim 1, wherein the elastic material and the nonwoven are needled and a surface of the elastic material exhibits, after assembling, a dynamic friction coefficient of between 2 and 3.

Description

EXAMPLES

(1) Different materials were used to manufacture bandages.

(2) 1. Materials Used

(3) a) Elastic Materials

(4) The materials used are commercial products, the names or references of which are as follows, and they are shown in table 1 in abbreviated form:

(5) hydrophilic polyurethane foams sold by AMS with a thickness of 4.5 mm (abbreviated to 4.5 mm foam) and with a thickness of 2.5 mm (abbreviated to 2.5 mm foam),

(6) 3D knitwear, sold by Louis Vuidon under the references 9315 and 9031 (abbreviated to Knitwear 9315 and Knitwear 9031).

(7) b) Nonwoven

(8) The examples use a self-adhesive nonwoven, based on crimped asymmetric bicomponent fibers, manufactured according to the teaching of the patent application WO 2008/015972, which carries the reference SJJ 146 from Kuraray.

(9) The fiber used is a fiber of the side by side type, based on polyester, the reference of which from Kuraray is PN-780.

(10) This nonwoven exhibits the following properties and characteristics:

(11) TABLE-US-00001 Nonwoven B Grammage (standard EN 9073-1) 134 g/m.sup.2 Thickness (standard EN 9073-2) 1.14 mm Elasticity (standard EN 14704-1) 87% Longitudinal lengthening (standard EN 9073-3) 104% Transverse lengthening (standard EN 9073-3) 65% Self-adhesion* 0.03 N/cm Number of crimped fibers 27/cm.sup.2 at the surface of the nonwoven** *measured according to the method described above **measured according to the method described above

(12) 2. Assembling

(13) Different assembling techniques were used to manufacture the bandages: needling or application of an adhesive by points.

(14) a) Conditions for Assembling by Needle

(15) The tests on laminating by needling were carried out on a Fehrer needling machine using a board comprising 2500 needles per linear meter.

(16) Two different types of needling were employed to prepare the compression bandages of the invention.

(17) Needling 1

(18) The implementational conditions on the needling 1 line are as follows:

(19) Output rate on the needling line: 1 meter/minute

(20) Penetration of the needles: 10 mm for example 1 and 13 mm for example 2

(21) Needling density: 50 punches/cm.sup.2

(22) The elastic material and the nonwoven are combined before needling 1 without prestressing the nonwoven.

(23) Needling 2

(24) The implementational conditions on the needling 2 line were as follows:

(25) Line speed=1 m/min

(26) Penetration of the needles: 13 mm

(27) Needling density: 50 punches/cm.sup.2

(28) The elastic material and the nonwoven were combined before needling 2 without prestressing the nonwoven.

(29) b) Conditions for Assembly by Application of Adhesive by Points Under Hot Conditions with an Engraved Cylinder

(30) Assembling with an adhesive was used when the application temperature of the adhesive necessary in order to deposit it is compatible with the nonwoven. When the bandage comprises a supplementary layer, the surface of the has to be sufficiently even for the adhesive to be able to be uniformly distributed.

(31) The product was produced on a Cavimelt apparatus for laminating by an engraved cylinder (left-hand part).

(32) Cylinder used=cylinder No. 6 Engraving Net 1

(33) Test conditions of the apparatus:

(34) Operating speed=2 m/min

(35) Rolling slot=0.3 mm

(36) Rolling cylinder pressure=3 bar

(37) Anvil roll pressure=2.5 bar

(38) Heating temperature=188 C.

(39) Temperature of the adhesive=180 C.

(40) The supplementary layer of foam was spread with adhesive and then the nonwoven was laminated. The hot melt adhesive used was a polyester adhesive having the Griltex D 2116 E trade name from EMS.

(41) All of the bandages produced and the assembling techniques are collated in table 1.

(42) TABLE-US-00002 TABLE 1 Example Elastic material Assembling 1 4.5 mm foam Needling 1 2 4.5 mm foam Needling 1 3 4.5 mm foam Adhesive 4 2.5 mm foam Needling 2 5 Knitwear 9031 Needling 2 6 Knitwear 9315 Needling 2

(43) 3. Performance of the Compression Bandages

(44) The performance of the compression bandages of examples 1 to 6 were evaluated in terms of working and resting pressures applied and of difference in pressure over time.

(45) The in vitro testing device and method described in the patent application WO 2007/113430, page 17, line 26, to page 19, line 18, was used.

(46) According to this method, the bandage is put in place around a cylinder with a total cover of 100% and then the circumference of the cylinder is continuously varied at a set rate between a resting position (smallest diameter) and a working position (greatest diameter), in order to mimic muscle contraction. Pressure sensors measure, over time, the values of the resting pressures and working pressures.

(47) The time difference between the working pressure and resting pressure measurements is 5 seconds and the frequency of the measurements of these two successive parameters is 0.2 Hz.

(48) In order to test the compression bandages according to the invention, the elongation at the putting in place of the bandage was determined as a function of the desired working pressure, for example using the tension/break curve as defined in the standard EN 9073-3. According to Laplace's law, the elongation to be carried out corresponds to the desired pressure.

(49) In order to appropriately put the bandage in place, the bandages were calibrated using a stencil, as described in the patent application WO 2007/113430, page 13, line 18, to page 14, line 6. If necessary, the value of the percentage of elongation at being put in place was refined by a few successive tests.

(50) Each of the bandages was put in place at a given elongation, expressed as percentage, which is shown in table 2.

(51) The Max. Pressure at T0 value corresponds to the first working pressure recorded immediately after putting in place and Delta at T0 corresponds to the difference in pressure between the first working pressure and the first resting pressure which are recorded immediately after putting in place. The Max. Pressure at T24 and Delta at T24 values correspond to the measurements recorded 24 hours after putting in place. The difference in each of these two values between T0 and T24 hours, Max. Pressure (T0-T24) and Delta (T0-T24), was then calculated.

(52) The loss in working pressure at 24 hours, Loss in Max. Pressure T24, with respect to the working pressure at being put in place, was also calculated by determining the ratio of the variation Max. Pressure (T0-T24) to the Max. Pressure at T0.

(53) The performance of the bandages according to the invention was compared with the bilayer compression systems sold by Urgo Limited under the K2 and K2 Lite names. The bandages of these commercial products were already calibrated.

(54) The combined results have been given in table 2.

(55) TABLE-US-00003 TABLE 2 Loss in Elongation at Max. Max. Max. being put in Pressure Delta Pressure Delta Delta Pressure Pressure Example place at T0 at T0 at 24 h at 24 h (T0-T24) (T0-T24) at T24 h Ktech 55% 31 15 23 12 3 8 25.8% K2 55% + 50% 44 19 35 17 2 9 20.4% K2 Lite 50% + 50% 33 10 25 8 2 8 24.2% 1 30% 77 28 67 30 2 10 12.9% 2 30% 87 32 76 34 2 11 12.6% 3 30% 69 15 58 16 1 11 15.9% 4 30% 34 12 34 16 4 0 0% 5 30% 42 8 37 13 5 5 11.9% 6 30% 45 13 44 16 3 1 2.2% 4 + Kpress 30% + 50% 63 18 53 21 3 10 15.9%

INTERPRETATION OF THE RESULTS

(56) The analysis of the results of table 2 demonstrates the performance of the compression bandages according to the invention.

(57) Generally, these results show that it is possible to treat all the pathologies described above as there exists, depending on the products, a value range for the working pressure at 24 hours which varies from 34 to 76 mm of mercury.

(58) It is also found that all these compression bandages exhibit an excellent retention, after 24 hours, of the pressure applied at being put in place. The large fall which is generally found for short-stretch bandages, of the order of 25 to 40% after 24 hours, and of the order of 20 to 25% for the bilayer systems which are the most effective, is here much lower because it is always less than 20% and generally between 10 and 15%, indeed even less than 5% for example 6 and zero for example 4.

(59) To be able to apply a high pressure and to retain it over time is a very important parameter for the treatment of lymphedemas, in particular leg lymphedemas, for which a pressure at 24 hours of greater than 60 mm of mercury and preferably between 70 and 100 mm of mercury is desired.

(60) Examples 1 and 2 are particularly well suited to these pathologies.

(61) Likewise, it is found that the value for the differences in pressure at 24 hours varies between 13 and 34 mm of mercury, which makes it possible to be appropriate for all the categories of leg ulcers indicated above.

(62) It is also found that the difference in pressure between working pressure and resting pressure does not decrease over time but on the contrary, unexpectedly, increases.

(63) Thus, for all the bandages, the difference between the Delta after putting in place and the Delta at 24 hours is negative.

(64) This result is all the more remarkable as it is obtained by a slower fall in the working pressure, Max. Pressure (which guarantees the effectiveness of the system), than that in the resting pressure.

(65) The compression bandages according to the invention are thus the first to improve their effectiveness over time.

(66) It may also be observed that these results are obtained with products based on different materials or assembled according to different technologies.

(67) Thus, if a bandage is targeted which exhibits a difference in pressure at 24 hours of the order of 15 to 25 mm of mercury, the compression bandages of examples 3, 4 and 6 can meet these specifications.

(68) Example 4 is particularly advantageous because this bandage can be used in several ways.

(69) Thus, in order to be able to treat mixed arterial and venous ulcers, what are desired, because of the arterial component, are low working pressures of the order of 30 to 35 mm of mercury while retaining a high difference in pressure.

(70) With the current bandages, it is very difficult to combine these two requirements. In order to obtain this result, it has thus been necessary to develop a new specific compression system, K2 Lite.

(71) It is found that the bandage of example 4, put in place at 30% elongation, makes it possible to obtain pressure values in the desired range and of the same order as K2 Lite while retaining a greater difference in pressure than that of K2 Lite.

(72) Likewise, this bandage exhibits similar values to those of the first bandage of the K2 system, the Ktech bandage.

(73) If the bandage of example 6, put in place at an elongation of 30%, is combined with the second bandage KPress of the K2 system, put in place at 50% as in the K2 system, it is found that a bilayer system is obtained with a value of difference in pressure at 24 hours which is greater than of K2. By virtue of the use of this first bandage, a bilayer system is obtained, the effectiveness of which is improved over time since the Delta (T0-T24) is negative.

(74) This example 4 is also noteworthy because, if the standard EN 14704-1 is applied, it is found that it is a long-stretch bandage since its elongation is 108%.

(75) There thus exists a long-stretch bandage which exhibits a very high difference in pressure at 24 hours (16 mm of mercury) which is of the order of that of a short stretch. Furthermore, example 4 exhibits a perfect retention of the working pressure since it does not decrease; its variation is zero 0%.

(76) All of the other examples have elongation values of less than 100% but the latter retain, indeed even increase, the difference in pressure and also the working pressure over time. Such a behavior corresponds both to a short stretch and to a long stretch.

(77) This particularly illustrates the advantages of the nonwoven based on short and crimped fibers which cannot be used alone as compression bandage as it does not exhibit the properties of a long-stretch bandage or of a short-stretch bandage but which makes it possible to obtain, in combination with an elastic material, bandages which combine the advantages of both types of bandages without their disadvantages, all the while giving bandages having an effectiveness which improves over time, another characteristic which has never been observed.

(78) Finally, the bandage of example 4 is advantageous because, after needling, loops of nonwoven appear at the surface of the foam which makes it possible to obtain a surface of the elastic material, in this instance the foam, which exhibits a dynamic friction coefficient of 3.87, which will reduce the sliding thereof over itself during movements.

(79) This bandage can thus, as explained above, according to the treatment targeted, be used alone, for example over a short period of time of 1 to 3 days.

(80) This phenomenon is encountered for all the other needled examples in which the penetration of the needles is greater than 10 mm.

(81) For example 1 with a foam having a thickness of 4.5 mm and a penetration of the needles of 10 mm, no loop appears at the surface of the foam.

(82) Thus, for examples 2, 5 and 6, dynamic friction coefficients of 3.58, 3.62 and 3.79 are respectively found.