SE544563C2 - 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"

[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"

[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"

[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 of different 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 or dip 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 polymer adheres to the calendared layer through the open fabric. 4. 4. 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"

[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 gives certain performance benefits. 6. 6. 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 thread constitutes one so called wale. A disadvantage is that the first and second stitch yarns in each pair are ihteriinited together vvhich means that hoth stitch yarnscross the warp thread and huiid up a thictrer tahric than necessary. Further, thewaie in this seiution gets by this design a mere er iess ”square” cross-section andby that the peiyrnei' Which is appiied te this enen fabric With any et known methedsdescribed above, huiids up an even thioker membrane. Further, the fabric as tfveiias a eernpiete niemerane gets rather “stittw due to a that each waie et the fabric israther tight With iew tiexihiiity, which is negative ter the totai tensiie strength in theWare direction as weti a negative eencerning resistance te tear torces. Theindividuai yarns and thread are :nere easiiy snapped when expesed te tensiiestress. iftihen stich a tahric is embedded into a poiyrner ter use as a memhrane,ter exarnpie tor reeting, with ter exarnpie a rnethed ot doubie~iayered coating, thepeiynier ot the two iayers preterabiy must attach te each other in the tree space inthe courses (between the Waies). Since ttiis seiution causes setiaretorrned andrather wide ifvaies, the eeiymer gets a sntaiier contact area bettrreert the iayers oneach side et the tahric. Thus, there is a need et a soiutien which prevides a thinnerwarp knitted tabric than the prier art and ytfitich rriay he used in one or severaiiayers et a membrane er the iike, and which has a high tensiie strength and high resistance to tear.

Summary of the invention 7. 7. 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 still is very thin, compared to prior art. 8. 8. 8. id="p-8" id="p-8"

[0008] This object is achieved by a warp knitted fabric according to claim 1 and a membrane comprising such warp knitted fabric according to claimIGÜQQ] 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 parallel warp threads (yarns), which extendin a first direction and further parallel weft threads (yarns) which extend in asecond direction which is perpendicular to the first direction. The warp knitted fabric further comprises parallel 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 inlay thread per wale, which inlay 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, whereinthe inlay thread is lead in the meandering pattern between the first and secondstitch yarns such as it passes over the warp thread of the wale on only one side,the first side of the knitted fabric. iüíiiíti By such warp knitted fabric, with paraiiei stitch yarns en respective sidesot' one warp thread together vtfith a rrteanderirig pattern of the iniay 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 inlay thread is lead between the first and second stitch yarns,which is not the same as if the inlay 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 the inlay thread and the parallel and straight pillar stitched stitch yarns. iišíit t] According to an entbodiitteht, the iniay thread is iead in a meanderingpattern between the first and second stitch yarns such as the iniay thread engageswith the first stitch yarn ih every odd cottrse in the first direction oi the warp knittedfabric and engages with the second stitch yarri in every even course in the first direction of the warp knitted fahric. in that way the warp knitted fabric disciose a pattern which is esoeciaiiy suitehie when a thin tehric is needed, since the iniay thread oniy erigages in every odd course with one iriiay thread, tütit2t According to an errihodiniertt, the iniay thread is iead in a rneanderingpattern between the firat and second stitoh yarna such as oassing over the onewaro thread ot the waie on the tirst side ofthe i-tnitted fahric in direction towardsthe tirat stitoh yarn, toitowed hy being threaded around the tirst stitch yarn in anodd course, toiiowed hy passing over the one waro thread ot the waie on the tirstside ot the itnitted tahrio in direction totfvards the second stitch yarn, toiiowed hybeing threaded around the second stitch yarn in an even course which toiiowsafter the odd course in the firat direction, in a reoeatirtg rneandering oattern suchas the iniay thread is threaded around the first stitch yarn in every odd course andaround the second stitch yarn in every even course in the first direction ot the warpknitted tahric. By that the intay thread oniy is arranged at one side (the tirst side) otthe Ware thread, the Ware itnitted tahric is thinner compared to it the iniay threadtft/ere passing through the tahric to the other side. When ooating or otherprocesses iike douhieiayered coating which are mentioned in the background, isused to produce a rnernhrane tfirith the tahrio, a hetter adheaion hettfveen thedcuhie ooiynfier-iayers is achieved it the nurnher ct threads per course is keot iow,to gorovide open apertures between the tvaies ot the course. Known tahrics stitches the iniay thread inte the stitch yarn in every course which means a thicker tahric. tištitíš] According to an enthodirnent, the iniay thread passes over the one tft/arethread suhstantiaiiy at an intersection hetween the warp thread and the weftthread. ttitfitlt] According to an ernhodintent, the hittar stitch ot the tirst stitch yarn isstitched into the waro itnitted tahric such as the tirst stitch yarn extends on hcth thetirst side and the aeoond side ot weft thread, and wherein the piiiar stitch ot thesecond stitch yarn is stitched into the warp itnitted tahric such as the second stitch yarn extends on hoth the tirst side and the second side ot each tft/ett thread. ttiütši] According to an ernhodiment, the niiiar atitch ot the second stitoh yarn ot each waie is a rnirror copy ot the oiiiar stitch ot the first stitch yarn ot each tvaie, trvhereirt the mirror copy of the piiiar stitch of the second stitch yarn is offset onecourse in the first direction reiatiye the piiiar stitch of the first stitch yarn. The rnirrorcooy has a retiection piane at the yvarp thread of the waie and due to themeandering pattern of the iniay thread between the first and second stitch yarns, the rnirror cooy of the piiiar stitches reiative each other is oftset one course. itšüiíš] According to an embodiment, the iniay thread is threaded around the firstand second stitch yarns in such a ieose manner such as the first and second stitchyariis remains their paraiiei extension at opposite sides of the one warp thread, inthe first direction. By that the first and second stitch yarns rernain theirsdhstantiaiiy straight extension direction in the warp knitted fahric, due to the iooserneandering iniay thread in engaging contact *with the first and second stitch yarns,the fabric is kept thin dee to that no stitch yarns pass over the warp thread iiite inknown soiutions. This aiso means that the warp knitted fahric gets higherresistance to tensiie stress and tear resistance, since each waie of the iriverititfetft/arr: i-tnitted fahric becomes narrower compared to known soiutioiis. As the waiebecomes narrower, iess surface wiii be exposed to the oeiyiner coating andadhesion to same. This mean that the yarn systems hecorne more ihovabie insidethe coating. This increased rnoveahiiity resiiits in higher tensiie strength and tearresistance due to the movahiiity of the fahrics thread/'yarns systems. As the waiesare narrcwer, the open apertores in the fahric yviii increase and thus the tiondingbetween the iayers of coatirtg aiso increases. This wiii tower the risk of deiarnination between the coating iayers. 17. 17. 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/yarn count (linear mass density) ranging from 80 dtex to 6600 dtex. {00”i8] According to an embodiment, the first and second stitch yarh comprise any material of polymer, metallic, inorganic, organic material or any hybrid of the materials (mix of materials). The first and second stitch threadiyarn couid he madeas endiess rnuitifiianierit or nionofiiarrient type as vveii as threads/yarns rnade irivarious spinning processes from stapie fihers or cornhinations vvith endiessmuitifiiament or ntonofiiarnent fioers. The threadfyarn count (iinear mass density) ranging from 22 dtex to 'iiOÜ dtex. fištiiši] According to an errihodirnent, the iniay thread comprises any material ofpolymer, metallic, inorganic, organic material or any hybrid of the materials (mix ofmaterials). The iniay thread couid he ritade as endiess itiuititiiarrient ormonofiiarnent type as weii as a thread rnade in various spinning processes fromstapie tihers or conihinations tfvith endiess iriuitifiiarnerit or rriorioiiiament fihers.

The thread/'yarn count (iinear mass density) ranging from 22 dtex to 1100 dtex. iutiâti] According to an ernhodiment, the iniay thread, vtfhere threaded aroundthe first stitcit yarn, is tiireaded through two ioops of the piiiar stitch of the firststitch yarn, and vvherein the iniay thread, where threaded around the second stitchyarn, is thread through tvvo ioops of the piiiar stitch of the second stitch yarn. Thismeans that at every engagentent hetvveen the iniay thread and the respectivestitoh yarn, the iniay thread is threaded through two ioops of the stitch yarn. Thepiiiar stitches of the stitch yarns are mirror copies of each other hut due to the iniay thread, the mirror copy is (as expiained above) offset one course. fíiufi] According to a second aspect of the invention, a membrane whichoornprises the Warg kriitted 'iahric according to any of the previousiy desorihedenthodirttent is disciosed, irvherein the mernhrane further comorises a poiymer,and wherein the warp knitted “iahric is at ieast partiaiiy ernhedded into the poiymer.By emhedding the inventive tfvarp itnitted fapric inte a poiymer, hy any of itnownmethods iike for exampie the ones described in the background for producing amembrane, the irrverttive rnemhrane provides high tensiie and tear strength, highfiexihiiity and other key properties due the thin design of the vvarp knitted fahric and hy that the thin design of the roofing rnerrihrane. iÜGEZ] According to an emhodirnent, the merrihrane is a roofing rnerrihrane. The vifarp knitted fahric is especiaiiy advantageous for roofing rnemhranes since the roofihg rnertthrene inciudihg the inventive vvero knitted fabric comprises the Characteristics described etiove, which is erueiei to rooting rrierrihraries. 23. 23. 23. id="p-23" id="p-23"

[0023] Gi course, other rnernhreries ehci eppiicetions ere possihie since thewarp knitted rahrio is edventageoiis to use iri ehpiicetions where a thinnerreiniorcerrreht is desired. The kriit “iehrie rney he treated with eriy suitetiiecerriposition during the process ef producing the fabric, hut the treatment rriay aisohe eppiieti to the verhs before pretiueing the fabric, ter exernpie using pre-treatedvarnsithreeds. Sorrie treetrriehts rney ihciiide edhesion prornoters, ariti-vvioirihgeheniistries, eoierehts, enti-iiiierohiei eherriistries, ehresion resistance, UVstehiiizers, and sirniiar. The were knitted fabric rney further he caieridered tefurther reduce its thicitrwess and hy thet the thieirriess ot the rrierhhrehe in which it is erntiedtieri.

Brief description of drawinqs 24. 24. 24. id="p-24" id="p-24"

[0024] The iriveritieri wiii now he described, hv way of exerripie, with reference to the eoeempenying dravvirigs ih vvhich: . . . id="p-25" id="p-25"

[0025] Fig. 1 is a sohernetic top view of e part ef e vtfare knitted fehrie according to the invention. 26. 26. 26. id="p-26" id="p-26"

[0026] Fig. 2 shows e eiose-iip ot e warp knitted fehrie ot Fig. i ih e perspective VÉQW.

Description of embodiments 27. 27. 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 weft threads compared to the real warp knitted fabric to show the design of the fabric more 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 warpknitted 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. It 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 tighterwale. Instead, 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 prior art fabrics and expose a smaller surface to the coating layers. As the wales 4 are narrower 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 increasing the key properties in end uses as roofing membranes and like. 28. 28. 28. id="p-28" id="p-28"

[0028] Fig. 2, shows a close-up view of the warp knitted fabric 1 seen in aperspective vievtf. The view shows 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 of wales 4 and courses 6b, 6c of the inventive warp knitted fabric[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-ca||edpillar 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. In 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 direction X, as mentioned above in relation to Fig. 1. In 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 intersectionbetween the warp thread 3 and the weft thread 2, followed by being threadedaround the first stitch yarn 5a in an odd course 6a, 6c by being threaded throughtwo loops 10a ofthe 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. In 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 of the pillar stitch 8b ofthe second stitch yarn 5b. This is repeated in a meandering pattern throughout the warp knitted fabricWÜEÜ] Aitriough the description above shows various specific emhodiments,they shoutd not be oonstrued as Eimiting the seooe ot the invention but areessentially there to iiiustrate various possibie ways of practioing the inventioritaiiing within its soope. References to an eiernent in singuiar are not ineant tornean "one and oniy one" unless it is specitioaiiy expressed, out rather "one orrnore”. Et is en intention that eiernents ntentioned in the described erntiodirnentscover aii structurai and 'tunctionai eouivaierits to the eieinents known to thosesidiied in 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) tothe second stitch yarn (5b) and back again in a repeating pattern through the wale(4), wherein the inlay thread (7) is lead in the meandering pattern between the firstand second stitch yarns (5a, 5b) such as it passes over the warp thread (3) of thewale (4) on only one side, the first side (A) of the knitted fabric (1 ).

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 least partially embedded into a polymer.

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