SE2150473A1 - Warp knitted fabric and a membrane comprising such warp knitted fabric - Google Patents

Abstract

The patent application relates to a warp knitted fabric (1) for roofing membrane and a membrane comprising such fabric. The warp knitted fabric comprises parallel warp threads (3) extending in a first direction (X), parallel weft threads (2) extending in a second perpendicular direction (Y) relative the first direction (X) and parallel wales (4) extending in the first direction (X). Each wale (4) comprises one of the warp threads (3) and a first and a second stitch yarn (5a, 5b) which each is parallelly arranged at opposite sides of the one warp thread (3), The warp knitted fabric (1) further comprises an inlay thread (7) per wale (4), which is lead in a meandering pattern between the first and second stitch yarns (5a, 5b), from the first stitch yarn (5a) to the second stitch yarn (5b) and back again in a repeating pattern through the wale (4).

Description

WARP KNITTED FABRIC AND A MEMBRANE COMPRISING SUCH WARPKNITTED FABRIC Technical field 1. 1. 1. id="p-1" id="p-1" id="p-1"

[0001] Present invention relates to a warp knitted fabric suitable for differentkinds of membranes and a membrane comprising such warp knitted fabric.Particularly, the inventive warp knitted fabric is suitable for roofing membranes.

Background art 2. 2. 2. id="p-2" id="p-2" id="p-2"

[0002] lt is well known to use different kinds of membranes for use within roofingand other types of applications like sun protection screens, tents, air ducts,ventilation ducts, tunnel lining, suspended ceilings, advertisement mesh, poollinings etc. The invention is first of all directed to a use within roofing but may of course be used also in other applications like the ones presented above. 3. 3. 3. id="p-3" id="p-3" id="p-3"

[0003] Membranes of this kind normally comprise a fabric which is embedded asa layer into some kind of polymer or a fabric which comprises a surface finishing,such as chemical binders for PVC coating or other types of coating. There are anumber ofdifferent known methods of applying the polymer to the fabric, such ascalendaring, where the polymer (coating) is applied between heated rollers whichare pressed to each other with high pressure such as a foil is formed whenpressing polymer between the rollers. This foil is then pressed firmly on the fabricto a desired thickness. Another method is to use a "screen" which is a perforateddrum in which the polymer is applied and is pressed out through the perforation.The fabric runs between this drum and a roller and the polymer is by that appliedto the fabric. Other similar methods are available, where the polymer is distributed(coated) over the fabric by for example a wiping knife or the like. For open fabricsother methods are available, for example dipping, dip coating, immerse coatingetc. Yet an alternative method for open fabrics is where the fabric is laminatedbetween two foils where adhesion may occur by direct contact between the foils orby a third component like an adhesive. The most common alternatives nowadaysare for double-sided coated membranes combinations of for example dipping ordip coating and some of the above-described method, where the dipping/dip coating is a pre-impregnation of the fabric which creates high adhesion betweenthe fabric and the coating since the pre-impregnation increases the adhesion tothe coating. For more open fabrics, the most common method is to use double-sided coated membranes with a combination of calendaring in a first step followedby coating in a second step, which creates high adhesion due to the liquid polymeradheres to the calendared layer through the open fabric. 4. 4. 4. id="p-4" id="p-4" id="p-4"

[0004] The specific demands of a membrane for use within roofing are highdemanding properties regarding wind-up lift, tensile strength, non-wicking, tearstrength and cold bending. The combination of weft insertion warp knitting fabricformation and designed finishing/coating results in that these high demands may be met. . . . id="p-5" id="p-5" id="p-5"

[0005] One problem with known solutions has been to provide a membranewhich is thin but still copes with the high demands such as high tensile strengthand high tear strength. The design of the warp knitted fabric must be adapted toprovide a thin layer of fabric to be used for the membrane, to get a thin membrane.lt has been found that having a thinner fabric layer within the membrane givescertain performance benefits. 6. 6. 6. id="p-6" id="p-6" id="p-6"

[0006] One example of a knit fabric for use in roofing membranes is presentedin EP 3 250 738 B1, which discloses a knit fabric which is advantageous to use inapplications where a thinner reinforcement is desired. The knit fabric containing astitch yarn set containing pairs of stitch yarns, a warp yarn set containing inlaywarp yarns, and a weft yarn set containing weft inserted yarns. Each pair of stitchyarns comprises a first stitch yarn and a second stitch yarn, where the first stitchyarn has a two bar first stitch pattern comprising repeating pattern of at least onetricot stitch optionally followed by at least one pillar stitch and the second stitchpattern comprises a mirror image to the first stitch pattern. The first stitch yarn andthe second stitch yarn within each pair of stitch yarns are interlinked together, butthe first stitch yarn and second stitch yarn of one pair of stitch yarns are notinterlinked with first stitch yarn and second stitch yarn of adjacent pairs of stitchyarns. The two stitch yarns together with one warp thread and the inlay threadconstitutes one so called wale. A disadvantage is that the first and second stitch yarns in each eair are interiinked together which means that both stitch yarnscross the vvare thread and buiid up a thicitertabric than iiecessary. Further, thevvaie in this soiution gets by this design a more or iess "square" cross-section andhy that the peiymer which is appiied te this open fabric with any et known niethodsdescribed above, buiids up an even thicker rnemhrane. Further, the fabric as vveiias a corripiete rnernhraite gets rather "stift" due to a that each waie et the fabric israther tight with iow tiexibiiityf, which is negative for the tetai tehsiie strength in theware direction as vveii a negative concerning resistance to tear torces. Theindividuai yarns and thread are mere easiiy snapped vvhen exposed te tensiiestress. tft/hen such a tahric is embedded into a pciyrner tor use as a membrane,tor exarnpie ter roetiitg, with tor exampie a method et doubieiayered coating, theooiymer et' the two iayers preterabiy must attach to each other in the tree space inthe courses (between the waies). Since this seiution causes sduare~torrned andrather vtfide vvaies, the ooiymer gets a sntaiier contact area between the iayers eneach side ot the fabric. Thus, there is a need ot a soiution which provides a thinnerwarp knitted tabric than the prior art and vvhich may be used in ene er severaiiayers ot a mehtbrane er the iike, and vvhich has a high tensiie strength and highresistance to tear.

Summarv of the invention 7. 7. 7. id="p-7" id="p-7" id="p-7"

[0007] An object of the present invention is to provide a warp knitted fabric aswell as a membrane which by its design has high tensile and tear strength and stillis very thin, compared to prior art. 8. 8. 8. id="p-8" id="p-8" id="p-8"

[0008] This object is achieved by a warp knitted fabric according to claim 1 anda membrane comprising such warp knitted fabric according to claim 12.

[GQGQ] According to an aspect a warp knitted fabric for roofing membrane isdisclosed. The warp knitted fabric has a first side and an opposite second side,and the warp knitted fabric comprises para||e| warp threads (yarns), which extendin a first direction and further para||e| weft threads (yarns) which extend in asecond direction which is perpendicular to the first direction. The warp knitted fabric further comprises para||e| so-called wales which extend in the first direction, wherein each wale comprises one of the warp threads and a first stitch yarn and asecond stitch yarn. The first and second stitch yarns are parallelly arranged atopposite sides of the one warp thread, wherein the first and the second stitchyarns are stitched into the warp knitted fabric with a repeating pattern of a pillarstitch per course of the warp knitted fabric. The warp knitted fabric furthercomprises an in|ay thread per wale, which in|ay thread is lead in a meanderingpattern between the first and second stitch yarns, from the first stitch yarn to thesecond stitch yarn and back again in a repeating pattern through the waie. [ttütüi By such warp knitted fabric, with paraiiei stitch yarns on respective sidesof one warp thread together with a meandering pattern of the ihiay thread, a thinwarp knitted with high tensile strength is achieved. This means that the inventivewarp knitted fabric is thinner compared to prior art warp knitted fabrics which areused for membranes such as roofing membranes, but still has the same or evenhigher tensile and tear strength compared to known warp knitted fabrics. This isachieved by that the in|ay thread is lead between the first and second stitch yarns,which is not the same as if the in|ay thread would be stitched to the first andsecond stitch yarns in a tight manner which would cause these to not keep theirparallel extension along the warp thread and parallel to the same. This allows theindividual threads/yarns to stretch more if exposed to tensile stress, compared toprior art fabrics, where the individual threads/yarns easier and earlier will snapcompared to the inventive warp knitted fabric with a meandering pattern of thein|ay thread and the parallel and straight pillar stitched stitch yarns. [öht t] According to ah embodirnent, the intay thread is iead in a meanderingpattern between the first and second stitch yarns such ae the iniay thread engageswith the tirst stitch yarn in every odd course in the first direction of the warp knittedfabric and engages with the second stitch yarn in every even course in the firstdirection ot the warp knitted fabric. in that way the warp knitted fabric disciose apattern vvhich is especiaiiy stiitahie vvhen a thin fabric is needed, since the iniaythread oniy engages in every odd course with one iniay thread. [ttütâ] According to an entbodintertt, the iniay thread is ieaci in a meanderingpattern bettiveen the first and second stitch yarns such as passing over the one were inreed ot tne weie on ine tirsi side oi tne kniited teoric in direction iowerdstne tirsi siiicn yern, ioiiovved ny being tnreeded eround ine tirsi stiicn yern in enodd course, toiioived ny pessing over ine one vverp inreed ot ine vveie on ine tirsiside ot tne knitied tecric in direction iowerds ine second siiicn yern, toiiowed nybeing inreeded eround tne second siiicn yern in en even course virnicn toiiowsetier ine odd course in ine first direction, in e rep-eating nieendering petiern sucnes ine iniey inreed is tnreeded eround tne tirsi stitcn yern in every odd course enderound tne second siiicn yern in every even course in ine tirsi direction ot tne vverpkniited teorin. By inet ine iniey inreed oniy is errenged et one side (tne tirsi side) oiine virerp tnreed, tne vverp knitied tenric is ininner cornpered io it ine iniey inreedwere pessing tnrougn tne tenric io ine oiner side. ifiinen coeiing or oinerprocesses iiiie douoieieyered coeiing vvnicn ere nieniioned in tne background, isused io produce e rneninrene wiin tiie ienric, e netier ednesioii neiween inedoiinie poiyrrienieyers is ecnieved it ine niininer ot inreeds per course is kent iovv,io provide open eperiures between ine vifeies ot ine course. Known tenrics siiicnestne iriiey tnreed inio ine siiicii yfern in every course vvnicn rrieens e inicker teorin. [tiiiiïi] According io en ernoodirnent, ine iniey inreed pesses over tne one vverptnreed suosientieiiy et en intersection between tne Werp inreed end ine wetitnreed. [titliiri] According io en eninodinieni, ine piiier siiicn ot ine tirsi siiicn yern issiiicned into ine vvero knitted teoric sucn es ine tirsi stitcn yern exiends on noin tnetirsi side end ine second side oi vveti inreed, end wiiereiri ine piiier siiicn ot inesecond stitcn yern is siiicned inio ine iverp knitied tenric sucn es ine second stitcnyern extends on coin tne tirsi side end ine second side ot eecn vvett inreed. [tiüiši According to en ernoodirneni, ine piiier stitcn ot tne second stitcn yern oteecn vireie is e rriirror copy ot ine piiier siiicn ot ine iirst siiicn yern oi eecn vifeie,yvnerein tne rnirror copy ot ine piiier stitcn ot tne second siiicn yern is otisei onecourse in tne tirsi direciion reietive tne piiier stiicn oi ine tirsi stitcn yern, "tne niirrorcooy nes e retiection oiene ei tne vvero inreed ot tne vveie and due io inerneerideririg peiiern ot ine iniey inreed oeiween ine tirsi end second stiicii yerns,ine niirror cooy ot ine piiier stiicnes reieiive eecn oiner is otiset one course. 13. 13. 13. id="p-13" id="p-13" id="p-13"

[0013] According to an embodiment, the intay thread is threaded around the firstand second stitch yarns in such a ioose manner such as the first and second stitchyarns remains their paraitet extension at opposite sides of the one tyarp thread, inthe first direction. By that the first and second stitch yarns remain theirsubstantiaiiy straight extension direction in the warp knitted fabric, due to the iooserneanderihg ihiay thread in engagihg contact with the first and second stitch yarns,the fabric is ixïept thin due to that no stitch yarns pass over the warp thread iike inknown soiutions. This aiso means that the warp knitted fahric gets higherresistance to tensiie stress and tear resistance, since each waie of the inyentivewarc knštted febric becomes rtarrower compared to known soiutions. As the vvaiebecomes harrower, tess surface Witt be exposed to the potyrner coating andadhesion to same. This mean that the yarn systems become more movabte insidethe coatihg. This increased moveabitâty resutts in higher tensiie strength and tearresistance due to the movahiiity of the fahrics thread/yarns systems. As the yvaiesare narrower, the open aperttires in the fabršc witi increase and thus the bondingbetween the iayers ot coattng aiso increases. This wiii iotyer the risk ofdeiarnination between the coating iayers. 17. 17. 17. id="p-17" id="p-17" id="p-17"

[0017] According to an embodiment, the weft thread (yarn) and the warp thread(yarn) comprise any material of polymer, metallic, inorganic, organic material orany hybrid of the materials (mix of materials). Further, the weft thread and thewarp thread could be made of endless multifilament or monofilament type as wellas threads (yarns) made in various spinning processes from staple fibers orcombinations with endless multifilament or monofilament fibers. The thread/yarncount (linear mass density) ranging from 80 dtex to 6600 dtex. 18. 18. 18. id="p-18" id="p-18" id="p-18"

[0018] According to an entbodintent, the tirst and second stitch yarn compriseany material of polymer, metallic, inorganic, organic material or any hybrid of thematerials (mix of materials). The first and second stitch threadlyarn coutd be madeas endiess rnuitifiiarnent or rnonofitamerwt type as weii as threadsiyarits made invarious soânnirtg processes from stapie fibers or combinations with endiessrnuitifiiarnent or rnonofiiameitt fibers. "the thread/yarn count (tinear mass density)ranging from 22 dtex to 1100 dtex.

[Gtltä] According to an embodlment, the inlay thread comprises any material ofpolymer, metallic, inorganic, organic material or any hybrid of the materials (mix ofmaterials). "the inlay thread could be made as endless multitilantent orrnonotilament type as well as a thread made in various spinning processes tromstapla tibers or combinations with endless rnultitilantent or ntonotilament tibers.The thread/yarn count (linear mass density) ranging trom 22 dtex to lttštli dtex.

[Gtiâti] According to an embodiment, the inlay thread, where threaded aroundthe first stitch yarn, is threaded through two loops of the pillar stitch ot the firststitch yarn, and wherein the inlay thread, virhere threaded around the second stltchyarn, is thread through two loops ot the pillar stitch ot the second stitch yarn. "thismeans that at every engagement between the inlay thread and the respectivestitch yarn, the inlay thread is threaded through two loops oi the stitch yarn, "thepillar stitches ot the stitch yarns are mirror copies ot each other but due to the inlaythread, the mirror copy is (as explained above) oltset one course.

[Qom] According to a second aspect ot the invention, a membrane whichcomprises the tifarp knitted tabric according to any ot the previously describedembodiment is disclosed, wherein the membrane further comprises a polyrner,and vifherein the virarp l and by that the thin design ot the rooting membrane. [titlââ] According to an embodiment, the membrane is a rooting membrane. Thewarp knitted tabric is especially advantageous tor rooting membranes since therooting membrane including the inventive tifarp l characterlstics described above, which is crucial to rooting membranes. [(3023] (fit course, other membranes and applications are possible since thewarp knitted 'labric is advantageous to use in applications where a thinnerreintorcement is desired. "the ltnit tabric may be treated yvith any suitable ooinpoeition during the orooese of producing the fehrie, out the treatment niey eieooe eppiied to the yarns before producing the fabric, for example using pretreatedyarns/threads. Some treetinents may inoiode edhesion pronioters, anti-vtfiekiiwgehernietriee, eoiorents, entienicrohiei chemietries, ahresien resistance, UVstahiiizers, end simiiar. The warp knitted fabric may further he eaiendered tofurther reduce its thickness end hy titet the thieknees of the rtiembrerte in which it is emhedded, Brief description of drawinqs 24. 24. 24. id="p-24" id="p-24" id="p-24"

[0024] The invention wiii now he described, by ttray of exampie, with reference to the eoeoinoenying dravvinge in which: . . . id="p-25" id="p-25" id="p-25"

[0025] Fig. 1 is e sohemetio top view of e part of e were knitted febrio eeoording to the invention. 26. 26. 26. id="p-26" id="p-26" id="p-26"

[0026] Fig. 2 shows e oiose«up of e warp knitted ieorio of Fig. 1 in e perspective VEQW.

Description of embodiments 27. 27. 27. id="p-27" id="p-27" id="p-27"

[0027] Fig. 1 shows a schematic top view of a part of a warp knitted fabric 1according to the invention. The warp knitted fabric 1 presented in Fig. 1 and Fig. 2comprises a first side A, which faces the viewer and an opposite second side B,which faces away from the viewer. The warp knitted fabric 1 comprises aconventional warp and weft design with parallel warp threads 3 (yarns) whichextends in a first direction X and parallel weft threads 2 (yarns) extending in asecond direction Y which is perpendicular to the first direction X. The schematictop view is deliberately shown with greater distance between warp and weftthreads compared to the real warp knitted fabric to show the design of the fabricmore easily. The term "wale" is well- known within the art and the warp knittedfabric 1 comprises parallel Wales 4, which extends in the first direction X, whereineach wale 4 comprises one of the warp threads 3 and a first stitch yarn 5a and asecond stitch yarn 5b. The first and second stitch yarns 5a, 5b are parallellyarranged at opposite sides of the one warp thread 3 and are stitched into the warp knitted fabric 1 with a repeating pattern of at least one so-called pillar stitch 8a, 8bper course 6a, 6b, 6c, 6d, of the warp knitted fabric 1. A course is also a well-known term within the art and may be described as the repeating pattern of"squares" in the first direction X and disclose the free space between two adjacentweft threads 2, which in Fig. 1 is shown by brackets 6a, 6b, 6c, 6d and so on. Theunique design of the inventive warp knitted fabric 1 is that each course 4 furthercomprises one inlay thread 7 per wale 4, which inlay thread 7 is lead in ameandering pattern between the first and second stitch yarns 5a, 5b, from the firststitch yarn 5a to the second stitch yarn 5b and back again in a repeating patternthroughout the wale 4. lt is preferred that the inlay thread 7 passes over the onewarp thread 3 substantially at an intersection 9 between the warp thread 3 and theweft thread 2. As can be seen in Fig. 1, the inlay thread 7 is lead between the stichyarns 5a, 5b, which means not stitched in a "normal manner" which would lead toa tighter wale. lnstead, the inlay thread is lead in a loose and meandering patternwhich by that leads to a looser fabric 1 where the first and second stitch yarns 51,5b remain their more or less straight extension in the first direction X, which isparallel to the warp thread 3 of the wale 4. This is crucial to achieve thecharacteristics of the inventive warp knitted fabric 1 such as high tensile strengthand high withstand to tear forces and the thin design. Known fabric of similar kindand for similar applications (like roofing membranes) have a tighter design wherethe inlay thread is stitched to the stitch yarns and the stitch yarns as well as theinlay thread pass repeatedly the warp thread more frequent. When the prior artfabric is subjected to tensile or tear stress, the individual fibers (warp threads andstitch yarns) snaps easier and earlier compared to the inventive warp knitted fabric1, since the latter, when subjected to tensile or tear stress, the fibers can moreeasily move inside the coating. This due to that the wale 4 is narrower than priorart fabrics and expose a smaller surface to the coating layers. As the wales 4 arenarrower the open apertures in the fabric 1 will increase and thus the bondingbetween the layers of coating also increases. This will lower the risk ofdelamination between the coating layers and provide advantages by increasingthe key properties in end uses as roofing membranes and like. 28. 28. 28. id="p-28" id="p-28" id="p-28"

[0028] Fig. 2, shows a close-up view of the warp knitted fabric 'i seen in aperspective view. The vievv shovvs a number of parallel warp threads 3 whichextends in the first direction X and number of parallel weft threads 2 extending inthe second direction Y, perpendicular to the first direction X. The warp threads 3and the weft threads 2 are together with the inlay thread 7 arranged in a number ofwales 4 and courses 6b, 6c of the inventive warp knitted fabric 1. 29. 29. 29. id="p-29" id="p-29" id="p-29"

[0029] The first and second stitch yarns 5a, 5b of each wale 4 are stitched intothe warp knitted fabric 1 such as the first stitch yarn 5a is stitched with a so-calledpillar stitch 8a into the warp knitted fabric 1 and by that the first stitch yarn 5aextends on both the first side A and the second side B of weft thread 2. ln thesame way, the second stitch yarn 5b is stitched with a similar pillar stitch 8b intothe warp knitted fabric 1 such as the second stitch yarn 5b extends on both thefirst side A and the second side B of each weft thread 2. The pillar stitches 8a, 8bof the first and second stitch yarns 5a, 5b are mirror copies of each other, but dueto the meandering inlay thread 7, which is threaded around the first and secondstitch yarns 5a, 5b as illustrated in the figure, the mirror copy of the second stitchyarn 5b is offset one course 6b, 6d in the first direction X relative the first stitchyarn 5a and its courses 6a, 6c in which the inlay thread 7 is threaded around thefirst stitch yarn 5a. By that, the inlay thread 7 is lead in a meandering patternbetween the first and second stitch yarns 5a, 5b, such as the inlay thread 7engages with the first stitch yarn 5a in every odd course 6a, 6c in the first directionX of the warp knitted fabric 1 and engages with the second stitch yarn 5b in everyeven course 6b, 6d in the first direction X of the warp knitted fabric 1. Further, theinlay thread 7 is threaded around the first and second stitch yarns 5a, 5b in such aloose manner such as the first and second stitch yarns 5a, 5b remains theirparallel extension at opposite sides of the one warp thread 3, in the first directionX, as mentioned above in relation to Fig. 1. ln Fig. 2 it can further be seen that theinlay thread 7 is lead in the meandering pattern between the first and second stitchyarns 5a, 5b such as it passes over the warp thread 3 of the wale 4 on only oneside, the first side A of the knitted fabric 1. The inlay thread 7 crosses, whendirected towards the first stitch yarn 5a, the intersection 9, which is the intersection between the warp thread 3 and the weft thread 2, followed by being threaded 11 around the first stitch yarn 5a in an odd course 6a, 6c by being threaded throughtwo loops 10a of the pillar stitch 8a of the first stitch yarn 5a. After this, the inlaythread 7 passes over the warp thread 3 and over an intersection 9, still on the firstside A of the knitted fabric 1, and further in direction towards the second stitchyarn 5b. ln the same way, the inlay thread 7 is threaded around the second stitchyarn 5b in an even course 6b, 6d, which follows after the odd course 6a, 6c in thefirst direction X, by being threaded through two loops 10b ofthe pillar stitch 8b ofthe second stitch yarn 5b. This is repeated in a meandering pattern throughout thewarp knitted fabric 1.

[QOBO] Although the description above shows various specific ernhodirnerits,they should not be oonstrued es iirniting the soope of the invention but areessentiaiiy there to iiiustrate various possibie ways ot practioing the inventiortfaiiing within its soope. References to en eiernent in singuiar are not rneant tornean "one and oriiy one" uniess it is speeiiieaiiy expressed, but rather "one orinore". it is an intention that eiernents mentioried in the described ernbodirnentscover aii struoturai and functions! eouivaients to the eiernents known to thoseskiiied ih the art.

Claims (13)

Claims

1. A warp knitted fabric (1 ) for roofing membrane, which warp knitted fabric(1) has a first side (A) and an opposite second side (B), the warp knitted fabric (1)comprising: parallel warp threads (3) extending in a first direction (X), parallel weft threads (2) extending in a second direction (Y) which isperpendicular to the first direction (X), parallel wales (4) extending in the first direction (X), wherein each wale(4) comprises one of the warp threads (3) and a first stitch yarn (5a) and a secondstitch yarn (5b), which first and second stitch yarns (5a, 5b) are parallelly arrangedat opposite sides of the one warp thread (3), wherein the first and the secondstitch yarns (5a, 5b) are stitched into the warp knitted fabric (1) with a repeatingpattern of a pillar stitch (8a, 8b) per course (6) of the warp knitted fabric (1 ),characterized in that that the warp knitted fabric (1) further comprises an inlaythread (7) per wale (4), which inlay thread (7) is lead in a meandering patternbetween the first and second stitch yarns (5a, 5b), from the first stitch yarn (5a) to the second stitch yarn (5b) and back again in a repeating pattern through the wale (4)-

2. Warp knitted fabric (1) according to claim 1, wherein the inlay thread (7)is lead in a meandering pattern between the first and second stitch yarns (5a, 5b)such as the inlay thread (7) engages with the first stitch yarn (5a) in every oddcourse (6a, 6c, ...) in the first direction (X) of the warp knitted fabric (1) andengages with the second stitch yarn (5b) in every even course (6b, 6d, ...) in thefirst direction (X) of the warp knitted fabric (1 ).

3. Warp knitted fabric (1) according to claim 1 or 2, wherein the inlaythread (7) is lead in a meandering pattern between the first and second stitchyarns (5a, 5b) such as passing over the one warp thread (3) of the wale (4) on thefirst side (A) of the knitted fabric (1) in direction towards the first stitch yarn (5a),followed by being threaded around the first stitch yarn (5a) in an odd course (6a),followed by passing over the one warp thread (3) of the wale (4) on the first side(A) of the knitted fabric (1) in direction towards the second stitch yarn (5b),followed by being threaded around the second stitch yarn (5b) in an even course(6b) which follows after the odd course (6a) in the first direction (X), in a repeatingmeandering pattern such as the inlay thread (7) is threaded around the first stitchyarn (5a) in every odd course (6a, 6c, ...) and around the second stitch yarn (5b)in every even course (6b, 6d, ...) in the first direction (X) of the warp knitted fabric (1)-

4. Warp knitted fabric (1) according to any of the previous claims, whereinthe inlay thread (7) passes over the one warp thread (3) substantially at anintersection (9) between the warp thread (3) and the weft thread (2).

5. Warp knitted fabric (1) according to any of the previous claims, whereinthe pillar stitch (8a) of the first stitch yarn (5a) is stitched into the warp knittedfabric (1) such as the first stitch yarn (5a) extends on both the first side (A) and thesecond side (B) of weft thread (2), and wherein the pillar stitch (8b) of the secondstitch yarn (5b) is stitched into the warp knitted fabric (1) such as the second stitchyarn (5b) extends on both the first side (A) and the second side (B) of each weftthread (2).

6. Warp knitted fabric (1) according to any of the previous claims, whereinthe pillar stitch (8b) of the second stitch yarn (5b) of each wale (4) is a mirror copyof the pillar stitch (8a) of the first stitch yarn (5a) of each wale (4), wherein themirror copy of the pillar stitch (8b) of the second stitch yarn (5b) is offset onecourse (6b, 6d, ...) in the first direction (X) relative the pillar stitch (8a) of the firststitch yarn (5a).

7. Warp knitted fabric (1) according to any of the previous claims, whereinthe inlay thread (7) is threaded around the first and second stitch yarns (5a, 5b) insuch a loose manner such as the first and second stitch yarns (5a, 5b) remainstheir parallel extension at opposite sides of the one warp thread (3), in the firstdirection (X).

8. Warp knitted fabric (1) according to any of the previous claims, whereinthe weft thread (2) and the warp thread (3) comprise any material of polymer, metallic, inorganic, organic material, or any hybrid of the same.

9. Warp knitted fabric (1) according to any of the previous claims, whereinthe first and second stitch yarns (5a, 5b) comprise any material of polymer,metallic, inorganic, organic material, or any hybrid of the same.

10. Warp knitted fabric (1) according to any of the previous claims, whereinthe inlay thread (7) comprises any material of polymer, metallic, inorganic, organicmaterial, or any hybrid of the same.

11. Warp knitted fabric (1) according to any of the previous claims, whereinthe inlay thread (7), where threaded around the first stitch yarn (5a), is threadedthrough two loops (10a) of the pillar stitch (8a) of the first stitch yarn (5a), andwherein the inlay thread (7), where threaded around the second stitch yarn (5b), isthread through two loops (10b) of the pillar stitch (8b) of the second stitch yarn(5b).

12. A membrane comprising the warp knitted fabric (1) according to any ofclaims 1 to 11 and a polymer, wherein the warp knitted fabric (1) is at leastpartially embedded into a polymer.

13. A membrane according to claim 12, wherein the membrane is a roofing membrane.