WO2006111664A2

WO2006111664A2 - Prosthetic knit fabric for support implants

Info

Publication number: WO2006111664A2
Application number: PCT/FR2006/000890
Authority: WO
Inventors: Alfredo Meneghin; Michel Therin
Original assignee: Sofradim Production
Priority date: 2005-04-22
Filing date: 2006-04-21
Publication date: 2006-10-26
Also published as: JP4938762B2; FR2884706A1; WO2006111664A3; FR2884706B1; EP1874990A2; JP2008536594A

Abstract

The invention relates to a prosthetic open-work knit fabric (1) for treating urinary incontinence and/or prolapses based on an arrangement of threads of a biocompatible polymeric material comprising at least one first lap defining a first pillar stitch weave, characterized in that this arrangement of threads also comprises at least two unmeshed inlay laps, the number of pillar stitch threads of this pillar stitch weave ranging from 6 to 12. The invention also relates to a support implant for treating stress incontinence and/or prolapses that is obtained from this knit fabric as well as to the method for producing a knit fabric of this type.

Description

Prosthetic knitting for support implants

The present invention relates to a perforated prosthetic knit for the treatment of urinary incontinence and / or prolapse, in particular for the manufacture of urethral support strips or strips in the treatment of stress incontinence in women, and only in the treatment of pelvic floor disorders mainly in women in general, also called prolapse.

The surgical treatment of stress incontinence in women generally involves the use of reinforcements in the form of strips placed under the middle urethra. The central part of the implant is disposed at this body and can be in contact with the latter to support it while the lateral parts of the implant are attached to stable anatomical elements such as for example the abdominal wall, the posterior surface of the pubis, or the obturator membrane, for example by means of staples, sutures or by simple tissue anchoring.

With regard to the treatment of prolapse, the implant is disposed on the one hand at or near the organ to be supported and on the other hand at the level of stable anatomical elements such as, for example, the abdominal wall, the posterior face of the pubis, the obturator membrane, the promontory of the sacrum, sacro-sciatic ligaments, for example by means of staples, sutures or by simple tissue anchoring.

In known manner, such a support implant must meet many constraints, and in particular have a suitable mechanical strength, particularly in the longitudinal direction, be biocompatible and flexible, These support implants must also be macroporous so as to integrate intimately and quickly into the tissues of the recipient while respecting the hollow viscera in contact with which they are implanted. These implants are advantageously made from monofil of biocompatible material so as to develop a minimal area potentially unfavorable for bacterial colonization. These support implants can be suturable. These implants may also advantageously be slightly longitudinally extensible so as to be easily towed in sometimes tortuous anatomical paths. Finally, it is desirable that these support implants be adapted to the anatomy and the morphology of the patient in both width and length. An essential property of these implants is their mechanical strength, which is particularly important for supporting the organs to be treated.

To increase this resistance, it has been proposed to increase the amount of material constituting these implants, for example by using thicker son, and therefore more resistant, or by making a more dense mesh.

However, since such implants are intended to remain permanently in the body of the patient, the increase in material entrained by these solutions is undesirable because contrary to the current criteria of tolerance and tissue integration of the implants of support and reinforcements. Another problem presented by the support strips is their tiling. By "tiling" is meant, in the sense of the present application, the spontaneous winding of the strip on itself, around its longitudinal axis, under tension stress along its length. These implants must retain in this form mechanical properties, especially in strength, sufficient, while limiting as much as possible the release of particles, that is to say son ends, when they are under stress and allow tissue anchoring mechanically stable.

Thus, there is the need for a knit, in particular macroporous and made from monofilament, which would make support implants, particularly in the form of strips, having both an optimal mechanical strength and a mass per unit area. the weakest possible.

The present invention aims to remedy this need by proposing a knit having an arrangement of particular threads, in particular having at least one mesh ply and at least two non-meshing plies, making it possible to produce support strips which are particularly mechanically strong and particularly light and stable.

The present invention relates to a perforated prosthetic knit for the treatment of urinary incontinence and / or prolapse, based on a son arrangement of a biocompatible polymer material comprising at least a first ply defining a first chain armor, characterized in that said son arrangement further comprises at least two non-meshing, partial weft webs, the number of warp threads of said chain armor ranging from 6 to 12.

The present invention also relates to the use of a prosthetic knit as above to obtain a prosthetic product for use in particular to obtain a supportive implant for the treatment of stress urinary incontinence and / or prolapse.

The knit according to the invention can be used directly as a support implant for the treatment of stress urinary incontinence and / or prolapse or it can be cut transversely to obtain such an implant.

Another object of the invention is a support implant for the treatment of stress urinary incontinence and / or prolapse, characterized in that it is obtained by transverse cutting of a prosthetic knit as above .

The present invention also relates to a method for manufacturing a perforated prosthetic knit as above, characterized in that it comprises the following steps:

- a °) a knitted structure is manufactured on a warp loom or Rachel according to a first web threaded continuously or available and being obtained from a first guide bar, the scale followed for the knitting of the son of said first web leading to the formation of a chain, and at least a first non-meshing web and a second non-meshing web, said non-meshing webs being threaded continuously or at disposal, each of said non-meshing webs being obtained from a web bar. gussets, the scale followed for the knitting of the threads of each non-weaving ply being such that for all the n yarns (A) of the chain-weave, n being from 6 to 12, any yarn of said non-meshing plies approaching the warp yarn n + 1 (A1, A11, A12) makes a half turn at said n + 1 chain yarn, said n + 1 chain yarn being called a free chain yarn,

- b) is demolded said free warp threads along the length of the knitted structure obtained in step a ⁰ ) and eliminates said free warp threads to obtain knits with a number of warp threads from 6 to 12 The knit or implant according to the invention has an excellent mechanical strength, in particular an excellent tensile strength, may be inelastic, and is thus quite suitable for the manufacture of a support implant for the treatment of the urinary stress incontinence and prolapse, without the need for a protective sheath. Moreover, thanks to the arrangement of specific threads that it comprises, in particular because of the presence of two non-meshing plies, knitting or implant according to the invention is particularly light, while having sufficient strength to support the organs to be treated. Thus, the knit or implant according to the invention comprises a minimum amount of yarn and therefore of material and nevertheless has the adequate strength to support the organs to be treated.

In particular, the presence of two non-meshing plies, in particular two intermeshing non-meshing plies, that is to say whose respective guide bars move symmetrically with respect to one another and staggered one by relationship to the other in the direction of the manufacture of the knitted structure on the knitting machine, provides knits and / or strips and / or implants with very good resistance to lateral compression. Thus, when one compresses, for example between two fingers, the two opposite longitudinal edges of a knit, strip and / or implant according to the invention obtained from said knitted structure, this knit, band and / or implant keeps significantly the same width. Preferably, the width loss of a knit, strip and / or implant according to the invention under the effect of the compression of its two opposite longitudinal edges between two fingers is less than 10%. The knit, tape and / or implant according to the invention is therefore particularly stable in handling, in passing through possible ancillaries (needle eye, cannula, etc.) and in the tissues of the patient (limitation of the rope effect ).

Because of its particular son arrangement, the knit tape and / or implant according to the invention therefore has no risk of unraveling.

Furthermore, because of its manufacturing process, this knit has atraumatic and stable edges, that is to say without risk of fraying or releasing particles, allowing its introduction into the fabrics without protective sheath. Finally, all knits, strips or implants obtained from the same knitted structure have a homogeneous thermofixation and are easily manipulated. In the present application, "prosthetic knit" means a knit intended to be implanted in the human or animal body in the form of a prosthesis or of any other piece shaped at least in part with said knit.

In the present application, "openwork knit" means a knit whose armor or armor determine cells or voids in the thickness of the knit, these cells or voids may constitute channels opening on both sides of the knitting. Such openwork knit, also called macroporous, allows better tissue integration.

By "mesh tablecloth" is meant according to the present application, a sheet of son for which the scale followed for the knitting son leads to the formation of meshes. In known manner, a chain-weave web is a mesh web, while partial weft webs are non-mesh webs.

In the present application, the term "free warp thread" means a warp thread completely traversed by any weft yarn, in other words a warp yarn for which any weft yarn approaching and interacting with this warp yarn, for example by bonding with it, then performs a half-turn at this chain yarn, and this over the entire longitudinal dimension of the knitted structure.

In the present application, the density of a knit is measured according to ISO 3801,

the breaking force of a knit in the longitudinal direction and in the transverse direction is measured according to ISO 13934-1,

the elongation under 2 daN in the longitudinal direction is measured according to ISO 13934-1. Preferably, the number of warp yarns of the knit according to the invention ranges from 8 to 11, preferably from 9. Such a number of warp threads makes it possible to obtain a knit having a good mechanical strength in the direction of the length and good longitudinal and transverse stability. Preferably, the knit is made from yarns, monofilaments or multifilaments, a biocompatible polymer material selected from polypropylene, polyester, polyamide and mixtures thereof. Advantageously, said biocompatible polymer material is polypropylene.

In another embodiment, the knit according to the invention is made from yarns, monofilaments or multifilaments, of a biocompatible and bioabsorbable polymer material.

In yet another embodiment, the knit according to the invention can be made from a mixture of bioabsorbable bioabsorbable yarns and nonabsorbable biocompatible yarns. Thus, it is possible to realize temporarily reinforced implants including the skeleton is expected to remain permanently in the patient's body for minimal permanent support.

Preferably, the knit according to the invention is made from monofilament yarns having a diameter ranging from 0.05 mm to 0.15 mm, preferably from approximately 0.10 mm.

Such a diameter, associated with the particular arrangement of yarns of the knit according to the invention makes it possible to obtain an excellent mechanical strength without having to add the quantity of material by means of thick threads.

Preferably, the knit according to the invention has a thickness ranging from 0.20 mm to 0.40 mm, preferably around 0.30 mm.

In a preferred embodiment of the invention, the knit comprises cells having a diameter ranging from 0.3 to 1.5 mm, preferably from 0.3 to 0.9 mm. Such a structure allows improved tissue anchoring. Preferably, the knit according to the invention has a width ranging from 0.6 cm to 1.5 cm.

Preferably, the knit according to the invention has a basis weight of from 40 to 75 g / m ² , preferably from 50 to 60 g / m ² .

Advantageously, the breaking force of the knit according to the invention in the longitudinal and transverse direction, measured according to the ISO 13934-1 standard, ranges from 20 to 90 N, preferably from 40 to 9ON, preferably from 55 to 75 N. more preferably from 60 to 70 N.

Thus, the knit or implant according to the invention has both excellent mechanical strength, or breaking strength, and a low mass per unit area while being inelastic and insensitive to changes related to the conditions of use such as tiling, rope or deformations in the transverse direction, release of the particles. Such an implant is advantageous because it provides effective support organs to treat while minimizing the mass of foreign body implanted. Preferably, the knit according to the invention has an elongation under 2 daN in the longitudinal direction, measured according to ISO 13934-

1, less than or equal to 15%, more preferably less than or equal to 10%.

Preferably, the knit according to the invention comprises a first non-meshing web and a second non-meshing web, said first non-meshing web having the table 1-1 / 3-3 / 2-2 / 0-0 //, said second web non-meshing tablecloth showing the scale 3-3 / 2-2 / 0-0 / 1-1 //. Such scales are particularly advantageous because they make it possible to obtain a better maintenance of the warp threads as well as an excellent transverse and longitudinal mechanical resistance while retaining the widest possible cells and without addition of material. In one embodiment of the invention, the knit according to the invention has a number of rows of stitches / cm ranging from 13 to 18. Preferably, this number of rows of stitches / cm is 15. Such a number of rows of mesh / cm allows a better maintenance and a better blocking of the knitted structure. The knit according to the invention is not loose and is relatively dense.

Preferably, the knit according to the invention is heat set. In one embodiment of the invention, the knit according to the invention has a length ranging from 10 to 50 cm and constitutes a support implant for the treatment of stress urinary incontinence and / or prolapse.

In another embodiment of the invention, an implant according to the invention is obtained by transverse cutting of the knit according to the invention. Preferably, the implant according to the invention has a length ranging from 10 to 50 cm. The knit according to the invention is preferably manufactured according to a process comprising the following epices:

- a °) a knitted structure is manufactured on a warp loom or Rachel according to a first web threaded continuously or available and being obtained from a first guide bar, the scale followed for the knitting of the son of said first web leading to the formation of a chain, and at least a first non-meshing web and a second non-meshing web, said non-meshing webs being threaded continuously or at disposal, each of said non-meshing webs being obtained from a web bar. gussets, the scale followed for the knitting of the threads of each non-weaving ply being such that for all the n yarns (A) of the chain-weave, n being from 6 to 12, any yarn of said non-meshing plies approaching the warp yarn n + 1 (A1, A11, A12) makes a half turn at said n + 1 chain yarn, said n + 1 chain yarn being called a free chain yarn, FR2006 / 000890

S

- b) is demolded said free warp threads along the length of the knitted structure obtained in step a ⁰ ) and eliminates said free warp threads to obtain knits with a number of warp threads from 6 to 12 .

Thus, according to the method of manufacturing the knit according to the invention, all the warp threads, whether free or not, are knitted with the same guide bar.

Preferably, n is from 8 to 11, and more preferably n is 9. In a preferred embodiment of the process according to the invention, the yarns of the first ply in chain-weave are knitted according to a scale 1-0 / 0-1 //, the yarns of the first non-weaving ply are knitted according to a scale 1-1 / 3-3 / 2-2 / 0-0 //, the yarns of the second non-weaving ply are knitted according to a scale 3-3 / 2-2 / 0-0 / 1-1 //.

Preferably, the guide bar of the first ply according to chain weave is threaded continuously solid, the guide bar of the first non-weaving ply is threaded continuously 1 full, 1 empty, 3 full, 1 empty, 1 full, 3 empty, and the guide bar of the second non-meshing web is threaded continuously 1 full, 1 empty.

Advantageously, the two guide bars of the two non-meshing plies move in partial weft under three needles, symmetrically relative to each other, offset with respect to each other in the direction of manufacture of the knitted structure. Such a knitting, with the weft bars moving symmetrically relative to one another and thus crossing between them, makes it possible to obtain a better maintenance of the chains and thus a better resistance to the lateral compression of knits, implants and / or strips according to the invention obtained from this knitted structure.

Preferably, the knitted structure is subjected to a thermofixation operation between step a °) and step b °). The knitted structure is thus easily handled, in particular for the demaling step. Moreover, all the knits and implants according to the invention obtained from the same knitted structure heat-set have a homogeneous heat-setting which makes it possible to better guarantee the homogeneity of the physico-mechanical properties of one strip to the other after demagnage .

The invention will be better understood from the description which follows with reference to the accompanying drawings. FIG. 1 represents a simplified schematic drawing of a knitted structure comprising a first warp armor ply and two non-mesh plies making it possible to obtain the knit according to the invention,

FIG. 2 represents a knitted structure making it possible to obtain knits according to the invention, two of whose free warp threads are partially unraveled,

FIG. 3 is a representation of a scanning electron microscope "Itashi S 800", magnification X20, of the unraveling of a free warp thread of a knitted structure making it possible to obtain knits according to the invention,

- Figure 4 is a representation of a scanning electron microscope "Itashi S 800", X20 magnification, the heart of a knit or implant according to the invention.

In FIG. 1, for a knitted structure that makes it possible to obtain a knit according to the invention, EE 'represents the direction or transverse dimension of the knit, by FF' the direction or longitudinal dimension of the knit and by GG 'the direction or diagonal dimension of the knitting.

This figure shows the movements of the warp yarns and weft yarns for a knitted structure for obtaining a knit according to the invention, having a chain ply and two non-meshing plies. The A and A1 threads of the chain armor are shown in solid solid lines. The wire A1 is a free-chain thread within the meaning of the present invention. The threads of the first non-meshing ply are represented in fine solid lines: they are the B yarns. The yarns of the second non-spunlace ply are represented by a dashed line: these are the C yarns.

In this example, the first guide bar, corresponding to the chain armor is threaded continuously full. The second guide bar, corresponding to the first non-meshing sheet and son B, is threaded continuously 1 full, 1 empty, 3 full, 1 empty, 1 full, 3 empty. The third guide bar, corresponding to the second non-meshing web and son C, is threaded continuously 1 full, 1 empty.

The knitting scales for these three tablecloths are as follows:

- the chain ply (wires A and A1): 1-0 / 0-1 //,

the first non-meshing web (son B): 1-1 / 3-3 / 2-2 / 0-0 //. the second non-meshing sheet (thread C): 3-3 / 2-2 / 0-0 / 1-1 //. Thus, the warp yarn A1, as it appears in FIG. 1, is completely traversed by no weft yarn, or in other words, any weft yarn, that is to say any yarn B or C, approaching said yarn. A1 chain yarn, possibly binds with said A1 chain yarn, then performs a half-turn at this A1 chain yarn.

The free chain yarn A1 can thus be unraveled without consequences on the neighboring A chain threads, which are not free within the meaning of the present application, and therefore without destructuring the knit on either side of the A1 yarn. By pulling on the warp thread A1, the part of the knit on the left of this wire A1 is separated from the part situated to the right of this wire A1 without unraveling these two parts.

On the other hand, because any weft yarn approaching the yarn A1 makes a half-turn at this yarn A1, the edges of the separated parts have only one yarn B or C making a half-turn and are therefore smooth. No fraying occurs.

Such unraveling of a free-chain yarn A1 of a knitted structure making it possible to obtain a knit according to the invention is visible in FIG. 3, which is the representation of a photograph, taken under the scanning electron microscope "Itashi S 800 ", magnification X20, a demagnetizing zone of such a knitted structure according to Figure 1 and Example 1 of the present application. In the upper part of the figure, the wire A1 is unmated and the knit portions on either side of this wire A1 are not destructured. Their edges are smooth: only a wire C performs a half-turn. No knitting yarn is cut or frayed. As it appears clearly in this FIG. 3, by virtue of the particular threading of the threads of the non-meshing plies, the thread C making a half-turn at the edge of a separate part is integral with the heart of this separate part, c that is to say with the knit according to the invention. In this figure, the A1 wire is being unmaked. Thus, at the bottom of the figure, the wire A1 is still meshed with the C wires approaching him. At the end of the unraveling, that is to say when the yarn A1 has been peeled over the entire length of the knitted structure, the yarn A1 is removed from said knitted structure and the two parts of the knitted fabric from else of this wire A1 are completely separated. By unraveling in the same manner a second free warp thread, a strip of said knitted structure is completely separated, this band constituting the knit according to the invention. The distribution of son A1 allows to predetermine with great precision the width of each strip.

In Figure 2 is shown schematically a knitted structure 2 for obtaining knits 1 according to the invention. Two of the free warp threads, the wires A1 1 and A12, are partially unraveled. Thus, by completely unraveling these free warp threads A11 and A12, there is obtained a knit 1 according to the invention, namely a strip used in the treatment of stress urinary incontinence in women. Such strips may also be used in the treatment of prolapse. The heart of a knit, tape or implant according to the invention is shown in Figure 4, which is the representation of a photograph, taken with scanning electron microscope "Itashi S 800", X20 magnification. The knit or implant according to the invention corresponds to a zone of said knitted structure 2, between two consecutive free chain threads. Thus, the knit or implant itself does not include free warp threads. It does not present any risk of unraveling.

EXAMPLE:

A knitted structure was produced which made it possible to obtain a knit according to the invention from a polypropylene monofilament yarn, with a diameter of 0.10 mm, on a Rachel loom, with a chain ply and two non-meshing plies, according to the following scales for the different tablecloths:

the chain ply: 1-0 / 0-1 //, the first non-meshing ply: 1-1 / 3-3 / 2-2 / 0-0 //,

the second non-meshing sheet: 3-3 / 2-2 / 0-0 / 1-1 //.

The first guide bar, corresponding to the chain armor was threaded continuously full. The second guide bar, corresponding to the first non-meshing web, of partial weft, was threaded continuously 1 full, 1 empty, 3 full, 1 empty, 1 full, 3 empty. The third guide bar, corresponding to the second non-meshing nonwoven web, was threaded continuously 1 full, 1 empty. The threading of the two partial wefts was carried out so as to move under nine warp threads, this finally obtaining strips separated by about 1 cm in width each. Thus, in this example, 1 out of every 10 threads was a free warp thread within the meaning of the invention. The gauge used was 24 needles.

The guide bars of the two non-meshing plies moved in partial weft under three needles, symmetrically relative to each other, shifted relative to each other in the direction of manufacture of the knitted structure.

This knitted structure corresponds to the weave shown in FIG. 1 of the present application.

On leaving the trade, the knitted structure was subjected to a heat-setting operation. From this knitted structure, knits or strips were obtained by unraveling at least two consecutive free-knit threads. The knits or strips had the following characteristics:

- thickness: about 0.3 mm

diameter of the cells: approximately 1 mm. - width: about 1 cm.

- mass per unit area: about 50 g / m ² .

- breaking force measured according to ISO 13934-1 on a strip 1 cm wide and 20 cm long: 66 N.

The knit or strip thus obtained by demisting at least two free, preferably consecutive, chain yarns from said knitted structure has excellent tensile strength and is therefore very suitable for use as, or in the manufacture of a supportive implant for the treatment of stress urinary incontinence and prolapse.

For example, an implant 20 cm in length, or 30 cm in length or 40 cm in length can be prepared from this strip. Such an implant has a particularly low surface mass. Thus a minimum of material is implanted in the body of the patient to be treated.

Moreover, because of its manufacturing process, this implant is not elastic and has edges, including longitudinal, atraumatic allowing its implantation without protective sheath. Finally, all knits, strips or implants obtained from the same knitted structure have a homofixation homogeneous and are easily manipulated.

Claims

1. Prosthetic knit (1) perforated for the treatment of urinary incontinence and / or prolapse, based on a son arrangement of a biocompatible polymer material comprising at least a first ply defining a first chain armor, characterized in that said yarn arrangement further comprises at least two non-meshing, partial weft webs, the number of warp yarns of said chain armor ranging from 6 to 12.

2. Knit (1) according to claim 1, characterized in that the number of chain son is 8 to 11, preferably 9.

3. Knit (1) according to any one of the preceding claims, characterized in that it is made based son, monofilaments or multifilament, a biocompatible polymer material selected from polypropylene, polyester, polyamide and their mixtures.

4. Knit (1) according to claim 3, characterized in that said biocompatible polymer material is polypropylene.

5. Knit (1) according to one of claims 1 to 4, characterized in that it is made from a mixture of biocompatible son bioabsorbable and biocompatible son non-bioabsorbable.

6. Knit (1) according to any one of the preceding claims, characterized in that it is made of monofilament son having a diameter of 0.05 mm to 0.15 mm, preferably about

0.10 mm.

7. Knit (1) according to any one of the preceding claims, characterized in that it has a thickness ranging from 0.20 mm to 0.40 mm, preferably about 0.30 mm.

8. Knit (1) according to any one of the preceding claims, characterized in that it comprises cells having a diameter ranging from 0.3 to 1.5 mm, preferably from 0.3 to 0.9 mm .

9. Knit (1) any one of the preceding claims, characterized in that it has a width ranging from 0.6 cm to 1.5 cm.

10. Knit (1) any one of the preceding claims, characterized in that its basis weight ranges from 40 to 75 g / m ² , preferably from 50 to 60 g / m ² .

Knit (1) any one of the preceding claims, characterized in that its breaking force in the longitudinal direction and transverse, measured according to ISO 13934-1, is from 20 to 90 N, preferably from 40 to 9ON, preferably from 55 to 75 N, more preferably from 60 to 70 N.

12. Knit (1) any one of the preceding claims, characterized in that it has an elongation under 2 daN in the longitudinal direction, measured according to ISO 13934-1, less than or equal to 15%, preferably still less than or equal to 10%.

13. Knit (1) according to any one of the preceding claims, characterized in that it comprises a first non-meshing web and a second non-meshing web, said first non-meshing web having the scale 1-1 / 3-3 / 2-2 / 0-0 //, said second non-meshing web having the scale 3-3 / 2-2 / 0-0 / 1-1 //.

14. Knit (1) according to any one of the preceding claims, characterized in that it is heat set.

15. Knit (1) according to any one of the preceding claims, characterized in that it has a length ranging from 10 to 50 cm and is a support implant for the treatment of stress urinary incontinence and / or prolapse.

16. Knit (1) according to any one of the preceding claims, characterized in that it has a number of rows of stitches / cm ranging from 13 to 18, preferably 15.

17. Use of a knit (1) prosthetic according to any one of claims 1 to 16 to obtain a prosthetic product for surgical use, in particular to obtain a support implant for the treatment of stress urinary incontinence and / or prolapse.

18. Supporting implant for the treatment of stress urinary incontinence and / or prolapse, characterized in that it is obtained by transverse cutting of a prosthetic knit (1) according to any one of claims 1 to 16.

19. Implant according to claim 18, characterized in that it has a length ranging from 10 to 50 cm.

20. A method of manufacturing a knit (1) prosthetic according to claim 1, characterized in that it comprises the following steps:

- a ⁰ ) is made a knitted structure (2) on a loom or Rachel in a first web threaded continuously or available and being obtained from a first guide bar, the scale followed for the knitting the yarns of said first ply leading to the formation of a chain, and at least a first non-meshing ply and a second non-meshing ply, said non-meshing plies being threaded continuously or at disposal, each of said non-meshing plies being obtained from a guide bar, the scale followed for the knitting of the threads of each non-meshing sheet being such that for all the n threads (A) of the chain armor, n ranging from 6 to 12, any thread of said webs not meshing approaching the n + 1 chain yarn (A1, A11, A12) makes a half turn at said n + 1 chain yarn, said n + 1 chain yarn being called free chain yarn,

b °) said free warp yarns are stripped along the length of the knitted structure obtained in step a ⁰ ) and said free warp yarns are eliminated to obtain knits (1) whose number of warp yarns ranges from 6 to 12.

21. The method of claim 20, characterized in that n ranges from 8 to 11.

22. The method of claim 21, characterized in that n is 9.

23. The method of claim 22, characterized in that the son of the first tablecloth armor are knitted according to a scale 1-

0 / 0-1 //, the yarns of the first non-meshing ply are knitted according to a scale 1-1 / 3-3 / 2-2 / 0-0 //, the yarns of the second non-knitting ply are knitted according to a scale of 3-3 / 2-2 / 0-0 / 1-1 //.

24. A method according to claim 23, characterized in that the guide bar of the first ply in chain weave is threaded continuously full, the guide bar of the first non-woven mat is threaded continuously 1 full, 1 empty, 3 full, 1 empty, 1 full, 3 empty, and the guide bar of the second non-meshing web is threaded continuously 1 full, 1 empty.

25. The method of claim 24, characterized in that the two guide bars of the two non-meshing plies move in partial frame under three needles, symmetrically relative to each other, offset with respect to the other in the direction of knitting.

26. A method according to any one of claims 20 to 25, characterized in that the knitted structure (2) is subjected to a thermofixation operation between step a ⁰ ) and step b °).