Stretchable textile stay and transfer sheet
10781541 ยท 2020-09-22
Assignee
Inventors
Cpc classification
D10B2403/021
TEXTILES; PAPER
International classification
Abstract
A smart textile solution to facilitate permanent and long time staying in wheelchairs, chairs and on beds of chronically ill, less mobile and immobile patients especially in the elderly care, nursery care, rehabilitation and homecare in the embodiment of a textile based stretchable stay and transfer layer which can cover mattresses and cushions. Technical solutions within the invention are provided to guarantee a dry skin and to control the temperature thereof, the so called control of the micro climate, to lower and evenly distribute pressures and shear forces, and moreover to enable an easy low friction movement of patients in bed or in sitting positions, and to enable transfers into the bed and transfers out of the bed.
Claims
1. A stretchable stay and transfer sheet comprising a knit fabric having a user contacted outer surface, wherein the outer surface comprises raised and recessed areas with respect to a plane defined by the outer surface, wherein the raised and recessed areas are formed by stitches and are arranged in a predetermined pattern adapted to lower and distribute friction forces with a user contacting the outer surface, said pattern comprising raised areas having a horizontal dimension of one stitch or more in a direction of its stitch courses and of its stitch wales, raised areas of the pattern form gliding lines for the user contacting the outer surface, the gliding lines extending over a length and/or width dimension of the knit fabric; wherein at least some of the recessed areas have a shape selected from the group of square, rectangular, hexagonal, octogonal, polygonal, honeycomb, circular, oval, diamond, cross, and irregular and are surrounded by gliding lines forming rims of the at least some of the recessed areas.
2. The stretchable sheet of claim 1, wherein the knit fabric comprises a double knit fabric having a top layer and a bottom layer connected thereto by yarn extending between the top layer and the bottom layer, and wherein the top layer comprises the user contacted outer surface and at least the top layer includes elastic yarn.
3. The stretchable sheet of claim 1, wherein the gliding lines are continuous at least over the length of the fabric.
4. The stretchable sheet of claim 1, wherein the pattern comprises gliding lines oriented in a direction of the stitch wales of the fabric.
5. The stretchable sheet of claim 1, wherein the pattern comprises gliding lines oriented in a direction of the stitch courses of the fabric.
6. The stretchable sheet of claim 1, wherein the pattern comprises gliding lines oriented obliquely to the stitch courses and the stitch wales.
7. The stretchable sheet of claim 1, wherein the raised areas comprise stitches having upstanding longer loops of yarn than stitches forming adjacent recessed areas.
8. The stretchable sheet of claim 1, wherein the raised areas comprise tuck stitches.
9. The stretchable sheet of claim 2, wherein the top layer comprises a top layer multifilament yarn and the bottom layer comprises a bottom layer multifilament yarn, wherein filaments of the top layer multifilament yarn knitted in the top layer have a diameter being equal to or greater than a diameter of filaments of the bottom layer multifilament yarn knitted in the bottom layer.
10. The stretchable sheet of claim 1, wherein the top layer comprises a top layer multifilament yarn and the bottom layer comprises a bottom layer multifilament yarn, the top layer multifilament yarn has a number of filaments being equal to or lower than a number of filaments of the bottom layer multifilament yarn knitted in the bottom layer.
11. The stretchable sheet of claim 2, wherein the top layer comprises a top layer elastic yarn and the bottom layer comprises a bottom layer elastic yarn, wherein the top layer elastic yarn has a diameter and resilience higher than a diameter and resilience of the bottom layer elastic yarn knitted in the bottom layer.
12. The stretchable sheet of claim 2, wherein the top layer comprises a top layer elastic yarn and the bottom layer comprises a bottom layer elastic yarn, wherein the top layer elastic yarn has a diameter and resilience lower than a diameter and resilience of the bottom layer elastic yarn knitted in the bottom layer.
13. The stretchable sheet of claim 12, wherein in an unstretched condition a number of stitches per cm.sup.2 is between 50% and 100% greater in the bottom layer than in the top layer.
14. The stretchable sheet of claim 2, wherein yarns knitted in the top layer are selected from the group of: PES, PET, PTFE, UHMPE, PA.
15. The stretchable sheet of claim 14, wherein the top layer comprises only non-texturized yarn and the bottom layer comprises texturized yarn.
16. The stretchable sheet of claim 14, wherein at least one of the yarns is coated with a low friction polymer finish.
17. The stretchable sheet of claim 2, wherein the bottom layer has a smooth outer surface.
18. The stretchable sheet of claim 2, wherein the bottom layer comprises raised and recessed areas on its outer surface.
19. The stretchable sheet of claim 2, further comprising one or both of a water barrier layer or a gas and vapor permeable layer arranged on an outer surface of the bottom layer.
20. The stretchable sheet of claim 19, further comprising a membrane acting as one or both of the water barrier layer or the gas and vapor permeable layer.
21. The stretchable sheet of claim 2, further comprising one or both of a polyurethane layer or a dendrimere finish layer applied or attached to an outer surface of the bottom layer.
22. The stretchable sheet of claim 21, wherein one or both of the polyurethane layer or the dendrimere finish layer are covered by a single knit elastic fabric layer that is attached thereto.
23. The stretchable sheet of claim 2, wherein the double knit fabric is a 3-dimensional spacer fabric having monofilament or multifilament spacer yarns between the top layer and the bottom layer.
24. The stretchable sheet of claim 2, wherein the double knit fabric is a Jacquard fabric.
25. The stretchable sheet of claim 1 wherein the knit fabric includes elastic yarn.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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(4) The backings or surfaces of both the double knit layer and the top of the single knit low friction layer are treated with a PU-foam or spray finish/coating (e.g. Purtex.). Finally the double knit and single knit layers are interconnected via an elastic dot coating layer.
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DETAILED DESCRIPTION OF FIGURES
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(28) The double knit or single structure has an elastic behaviour which can be enhanced additionally by applying an elastic yarn or elastomer yarn, such as e.g. elastan. This also applies to the double 3-dimensional structure as mentioned earlier in the description of the invention with the interconnection monofilament and or multifilament yarns between the top and bottom plane.
(29) The double knit layer with top layer 1 and bottom layer or surface 2 in this possible embodiment are dot coated with glue dots, stripes or other glue patterns 5 to an elastic membrane layer 6, which blocks the water, but allows passage of water vapour and gases etc. The membrane 6 can be a monolithic elastic PUR membrane, a PET membrane, a PU membrane an electrospun nanofiber membrane, a PTFE membrane, a PUR layer applied via spraying or foam process (see
(30) This membrane layer 6 is dot glue coated with part 5 to a low friction single knit layer 7, which ensures low shear force sliding of the transfer and stay sheet on the underlying 3-dimensional textile mattress underneath and protects the membrane or water blocking layer from getting damaged during use. In order to ensure a low friction transfer the single knit layer 7 is composed of smooth PET-yarn, single knitted viscose yarn, PA11 yarn or combinations thereof.
(31) Based on the above described structures, different compositions can be developed for specific applications. In one embodiment for an active transfer and stay sheet there is a need for controlled but sufficient elasticity of 10-30% of the sheet that can be achieved by controlled guiding of the elasticity of the knitted fabrics via the knitting process itself and application of elastomeric yarn, but also by the variation in density and dispersion of the glue coating dots or glue stripes, lines 5. More glue dots will limit the elasticity and less glue dots or lines will enable elasticity more, also the size of the dots have impact on the elasticity. The stretching or elongation of the elastic sheet due to e.g. the pressure and contour of the human body will press these glue dots or stripes outwardly in case they have a non-elastic behaviour, creating an additional pattern of raised points, rims or planes in the upper structure which can be used as gliding structures on the bottom side of the complete stay and transfer a sheet. Another method to limit and control the elasticity is the application of printed silicone and or polyurethane lines and grid patterns on the top and or bottom surface of the described fabrics, or as an intermediate gluing layer. This grid like pattern can also have an extra function as pressure and shear forces distributing materials.
(32) The elasticity value also depends on the type of embodiment of the invention. For the embodiments of an active stay and transfer layer a higher elasticity, is required as described above. For passive stay and transfer sheets, a low elasticity is required due to the pulling at this sheet by the nurse or caregiver, in the range of 5-10%.
(33) This active transfer and stay sheet on which the patient lies has an overall neutral or positive effect on the pressure reduction of the human body and protects the 3-dimensional textile and foam mattress underneath from getting contaminated.
(34) The active stay and transfer sheet can get a production finish on the double top sheet with brushed rims to enhance gliding characteristics and smoothness.
(35) The double knit, two faced top structure of this 3-layer system in
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(38) Another embodiment of this double layered circular knitted structure is not visualized but represented largely by
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(55) The smaller raised diamond structures have dimensions of 5-10 mm and enhance the gliding characteristics enormously in all directions.
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DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
(60) A textile article suitable for permanent skin contact, reducing pressures, shear and friction forces and reducing frequent manual transfer handlings is provided by this invention, based upon an elastic stretchable, double knitted, two faced top surface layer, which is either a 3 dimensional double knitted spacer fabric structure with monofilament and or multifilament fibers or a single or double knitted jacquard structure. Various further solutions having possibly additional interconnected underlying layers with other functions are encompassed by the invention. The double knitted jacquard two faced structure and the 3 dimensional double knitted spacer structure can both be produced on a double knit circular so called jacquard knitting machine. The main purposes of this two faced top surface structure are: to minimize skin friction and physical stressing of skin and tissue due to friction, shear and pressure forces to quickly absorb sweat and urine droplets and transport these from skin to the bottom layer of the two faced structure to enable ventilation and venting of the structure to collect and save moisture in a special capillary structure in the bottom layer (for the 3-dimensional and jacquard structure). To allow easy washing and drying without wrinkles and folds in the surface.
(61) The top surface layer is in most embodiments constructed as a double knitted 3-dimensional structure or double knitted jacquard fabric, consisting of two interconnected layers (surfaces) with raised and recessed areas on the top surface which are preferably both manufactured of one fiber type, bound underneath by an elastic yarn. These raised areas on the top surface of the double knitted two faced elastic structure have horizontal dimensions of at least 1 or more stitches. They are preferably interconnected so as to form continuous lines or planes, and have contact with the skin or clothing of patients. They are normally produced from one type of preferably smooth low friction polymer fibers. These yarns are composed of multifilament PET or PA fibers, bundled together, texturized or non-texturized, having round, trilobal, hexagonal, octagonal, flat, rectangular or square cross sections each, and if necessary elastomeric fibers to enhance elasticity. To limit friction forces and to enable easy movement and repositioning of patients, the following characteristics are combined in the knitted fabrics: Raised lines and/or areas, which create gliding structures in the production and width direction of the fabric and/or in other possible gliding and repositioning directions in a horizontal plane. Especially the raised lines and/or areas in directions perpendicular or not parallel to the production direction and parallel to the knitting courses and perpendicular to the wales will significantly improve the gliding characteristics of the fabric. These raised lines can be manufactured on the top plane and if necessary also on the bottom plane. Use of thin, smooth, non-texturized polymer fibers in the top layer of the two faced knitting structure for the raised and recessed areas and/or lines. High water absorption and transport capacity of the fabric, realized via a substantial capillary difference between top and bottom plane. Special designs of the raised structures that allow raised structure lines to interrupt any blocking effect of sidelines of the stitch courses in the longitudinal/production direction, such as hexagonal structures with dividing lines, small diamond type of structures, etc. Variation in the diameter of the elastomeric fiber used in the top plane compared to the diameter used in the bottom plane to be able to have an easier deformation in case the elastomeric fiber is thinner on the bottom and to group more stitches closely together in case the elastomeric fiber is thicker in the bottom plane. The water absorption capacity in the bottom layer will be highly enhanced by increasing the amount of stitches from 50 to 100%. Low rewet of the top layer is also achieved by preventing the capillary properties of the monofil-filaments in the middle section of the 3-D double knitted jacquard fabric. A very smooth structure of the bottom layer is also preventing tear and shear forces between the skin of the patient and the top layer due to turning movements of the patient in bed. By using thicker non-texturized fibers in the raised structures, the tuck stitches (in German Fangmaschen) on top of the double knitted jacquard two faced structure and the 3-dimensional double knitted spacer structure various gliding lines and surfaces can be created which will enhance the smoothness and will result in lower friction forces. Due to its elastic behaviour towards the underlying mattress and its capacity to follow the body contour of a person, the risk of gliding out of bed is minimum when a person is lying on it.
(62) The shape and dimensions of the raised and recessed areas are not limited to one construction such as hexagonal, octagonal, honeycomb recessed areas with upstanding raised areas surrounding these recessed areas as boundaries or protruding walls, but can also have the shape of a recessed area like a cross, a stairs like structure, a diamond, pane or parallelogram shaped like structure, an hexagonal or octagonal, a circular or oval shape, a random irregular organic shape etc. The raised areas can be rims with a certain dimension consisting of at least 1 row of stitches, and are preferably in most embodiments continuously interconnected to each other for creating continuous gliding lines on the surface for the skin of the person lying on the knitted fabric. The raised lines and areas are manufactured, in most embodiments, of the same type of fiber as the recessed areas, and are parallel to at least the production direction of the circular knitted fabric, and also partly to a width direction of the fabric, enabling herewith in both basic horizontal direction an easy gliding and sliding of the human body. This can be enhanced, as mentioned above, by additional raised gliding lines and areas in other directions that are not parallel or perpendicular to the above mentioned directions. This can be done either via creation of lines extending under angels that are different from the other main lines of the recessed areas, via shifting the basic shapes of the recessed areas, and via combinations of these two methods.
(63) The raised areas can also have the shape of a backside or the inner side of a honeycomb structure, of a cross, of a diamond, of a circle, but raised upwardly, etc. in case of a two faced double knit jacquard structure. Also within these raised and recessed areas additional similar raised or recessed areas with the same shape but smaller dimensions can be knitted, interconnected preferably to the outer raised areas. The height of the raised areas can be variable depending on the specific characteristic of the circular knitting structure and a finishing process.
(64) As mentioned above, preferably non texturized or smooth thin multifilament PET yarns are used to enhance the smoothness of the top layer and if necessary the bottom layer of the transfer sheet. On the top layer the smooth, thin multifilament yarns will enable easy gliding, but also a soft contact and high comfort experience for the user's skin. On the bottom layer a similar type of fibers can be used to create flat or raised and recessed areas to enable easy, low friction gliding of the stay and transfer sheet on an underlying layer, which may be a water vapour permeable singe knit barrier layer or a 3-dimension spacer fabric mini mattress, which is described in another patent application of the inventors.
(65) The specific fibers which can be also used in the top structure besides multifilament texturized and non-texturized PET-yarns are PTFE fibers, UHMPE fibers, PA11 fibers, and PET fibers in the top plane coated with low friction polymer finishes. With multifilament non-texturized PET yarns, UHMPE and PTFE fibers the best smoothness and low friction results can be achieved. In an embodiment, in order to have a very smooth top layer of the circular knitted transfer and stay sheet this top layer is abraded with an appropriate device. Also a velours forming treatment can be applied afterwards.
(66) To create water absorption and transport in the knitted fabric a difference in capillary structure between top and bottom layers has to be generated during the knitting process. The difference in diameter and number of filaments between the top layer yarns and the bottom layer yarns, in both the double knit jacquard structure and the double knit jacquard 3-dimensional structure, results in a capillary functionality which is larger in its fiber dimensions and lower in the quantity or numbers of fiber filaments with the top layer and more refined, smaller in its fiber dimensions and larger in numbers of fiber filaments with the bottom layer of the same knitted structure, allowing water on the top layer to be transported to the bottom layer and if necessary to an interconnected intermediate layer where it will be absorbed. So the amount of capillary water transport canals is lower at the top layer as compared with the bottom layer of the same knitted structure, and/or the horizontal cavity dimensions of the capillaries are larger at the top layer than at the bottom layer of the same knitted structure, resulting in a hydrodynamic capillary transport mechanism for fluids. Additionally the embodiment created by a double knit 3-dimensional two faced structure can have a mixture of monofilament fibers and multifilament fibers in the interconnecting pile section and a similar difference in size and quantity of capillaries between top and bottom layer in order to stimulate water transport.
(67) Construction of the Above Mentioned 3-Dimensional Double Knitted Spacer Fabric:
(68) Gauge 18-50
(69) Weight 380/430 gram-m2. Thickness from 1 mm-4 mm.
(70) a. Top layer: PES yarn, non texturised: yarn fineness between decitex 70-150 and filaments 40-120. Elastan yarn decitex 22/F1: yarn fineness between decitex 11-78. b. Middle layer: PES Monofil Fiber: Fiber fineness between decitex 22-69. c. Bottom layer: PES yarn, texturised. yarn fineness between decitex 22-150 and filaments 40-120. Elastan yarn: yarn fineness between decitex 11-78.
Two-Faced Solution:
(71) Another preferred embodiment is made in connecting a middle layer through a monofil and a multifil yarn joining each other in the same machine feed. A monofil and a multifil yarn are joined together and feed into a machine feed that generates the distance between the top and bottom layers. The monofil yarn PES and the multifil yarn PES are bound in tuck stitches and processed together as two jointed yarns. In this way the water transport in the middle layer is enhanced significantly allowing the top layer to get dry quicker.
(72) Two-Faced-Solution:
(73) Gauge 18-50 double knit; Jacquard
(74) Weight 380/430 gram-m2. Thickness from 1 mm-4 mm.
(75) a. Top layer: PES yarn, non texturised: yarn fineness between decitex 70-150 and filaments 40-120. Elastan: yarn fineness between decitex 11-78. b. Middle layer: PES Monofil Fiber feeding into 1 slot with Multifil non texturised. Monofil fiber fineness between decitex 22-69, Multifil yarn fineness between decitex 22 69 and filaments 22-80. c. Bottom layer: PES yarn: yarn fineness between decitex 22-150 and filaments 40-120 Elastan: yarn fineness between decitex 11-78.
(76) 3-Dimensional Double Knit Fabric:
(77) Another preferred embodiment is realized on a double knit machine. Two single knit structures are bound together through connecting fibers. The advantage of this 3-D double knit structure is that it can be produced at a far lower weight and through this lower costs. Here also a choice can be made for the so called two joined solution in the middle layer of the 3-D double knit structure.
(78) 3-D Double Knit Structure: Gauge 18-E 50.
(79) Weight 240/330 gram/m2. Thickness 2.5 mm-5 mm.
(80) a. Top layer: PES yarn, non texturised: yarn fineness between decitex 70-150 and filaments 40-120. Elastan Fiber decitex 22/F1: Fiber fineness between decitex 11-78. b. Middle layer: PES monofil yarn. Feeding into 1 feed together with multifil non texturized yarn. Monofil yarn fineness between decitex 22-69. Multifil yarn fineness between decitex 22-69 and filaments 22-80. c. Bottom layer: PES yarn, texturised: yarn fineness between decitex 22-150 and filaments 40-120 Elastan yarn: yarn fineness between decitex 11-78.
(81) Additionally, the top layer or fibers used at the top layer can be treated with a finish, plasma or corona treatment and/or coating to enhance the hydrophilic characteristics resulting in faster water uptake and absorption. The combination of the raised and recessed areas of knitted yarns with different cross sections and number of filaments in a stay and transfer layer serving as a permanent bed sheet is an innovative characteristic of the innovation enabling low friction characteristics, an easy water and moisture uptake and downwards directed transport, and wrinkle free washing and use of the stay and transfer sheet.
(82) The upper yarns creating the raised structure are in one embodiment connected directly via the double knitted structure to a bottom surface or layer in which another type of these polymer yarns is used as second basic knitting yarn.
(83) In another embodiment the yarns of the top layer, which has raised and recessed areas manufactured from one type of fiber are connected to the bottom layer via interconnecting monofilament pile fibers and or multifilament yarns, creating a 3-dimensional circular knitted double faced structure. In this 3-dimensional embodiment the use of elastomeric yarns in the top and bottom layers enhances the stretching ability and elasticity enormously, but also pulls the stitches together enough to create a smooth surface.
(84) The diameter and strength of the elastomeric yarn in the top layer can be higher than the diameter and strength of the elastomeric yarn in the bottom layer, resulting in a larger deformation capacity at the bottom layer to follow the body contour more precisely and to distribute the weight of the person lying upon it more evenly. This effect can also be achieved by a variation of elastomeric yarn in the top layer versus the bottom layer, thus having a higher elastomeric yarn content in the top layer than in the bottom layer.
(85) The diameter and strength of the elastomeric yarn in the top layer can in another specific embodiment also be (50%) lower than the diameter and strength of the elastomeric yarn in the bottom layer, resulting in a largely enhanced capacity to store perspiration or larger void at the bottom layer due to the effect of the thicker elastic yarn to group 50 to 100% more stitches per cm.sup.2. Additionally the non-texturized PET yarn in the bottom can be replaced by a texturized yarn thereby enhancing the hydro-retention in the bottom plane. This will allow the, bottom layer to store vast quantities of liquid. This variation in elastomeric fiber amount will also result in a flat character and shape of the knitted fabric after production.
(86) The recessed areas of the double knitted structure in the version without monofilament fibers are basically knitted from the yarns which are being used for the bottom structure. They do not have contact with the skin, allowing ventilation, water absorption and uptake, and having a low friction functionality in case of the embodiment of the double knit jacquard construction.
(87) In the embodiment of the 3-dimensional circular knitted two faced structure, with monofilament and or multifilament yarns interconnecting the top and bottom surface, the recessed area is actually the larger part of the top surface plane on which an additional raised structure is knitted in the same process creating the initial contact surfaces for the body of the patient. This is done by creating a specific longer tuck stitch consisting of one yarn which is a tuck stitch of the same polymer yarn in the top surface, which produces one larger loop bound together by a knitting stitch giving the raised structure. These tuck stitches with raised structure look a bit like embroidery, but are created directly during the same circular knitting process, resulting in a raised structure which limits friction and enables easy movement in bed, or transfers in and out of bed, which can be even be enhanced when the used multifilament is thicker and is preferably a non-texturized yarn.
(88) The raised and recessed areas in the knitting structure are preferably constructed with a double knit circular jacquard machine, machine gauge 18 to 50, more preferable 24 to 42. This specific knitting structure can also be produced with a circular double knit 8 lock interlock machine generating loops of yarns at the top surface (so called frott), which can be treated afterwards as velours and can also be produced with a double knit circular knitting jacquard machine which is able to produce spacer fabric structures to create the 3-dimensional version with intermediate pile fibers as described above.
(89) Another embodiment of the invention to be produced by a double knit 8-lock circular knitting machine is an intermediate water absorbing layer and is a flat double knitted interconnected 2 layer structure, in which the top layer is consisting of cotton yarns and the bottom layer of very smooth polymer yarns. The double faced structure has a material composition consisting of 10-30% cotton fibers and 70-90% PET fibers. This structure can be used as a fluid or vapour absorbing layer underneath the two-faced double knitted 3-dimensional jacquard structure, when it's bonded with glue points to a smooth single backing layer with a barrier function (via means of a hydrophobic finish or venting membrane) to prevent leakage of fluids to a lower level. This combination of two knitted structures enables transfer, allows sliding of the two structures on top of the 3-dimensional warp knitted structure. A possible use of this embodiment is its use as a top layer and as a skin contact layer for patients suffering from incontinence.
(90) Another embodiment of the invention which can be manufactured by a double knit 8 lock circular knitting machine is a top or intermediate water absorbing layer and is a flat double knitted interconnected 2 layer fabric structure, in which the top layer is consisting of very smooth yarns with high decitex and low amount of filaments and at the bottom layer a texturized polymer yarn of low decitex with high amount of filaments. This structure can be also used as a fluid or vapour intermediate absorbing layer in combination with a smooth single bonded backing layer with barrier function (via means of a hydrophobic finish or venting membrane), allows sliding of the two structures on top of the 3-dimensional warp knitted structure) in the use as intermediate layer, or allows sliding of a patient when it is used as top layer. The embodiment can thus possibly be used as a top or intermediate layer as mentioned above in the paragraph with the already mentioned two faced embodiments.
(91) Interlock Barrier Layer: Gauge 18-50. Pique Structure. a. PES yarn, non texturised. Width of 185 cm. yarn fineness between decitex 50-150 and filaments 40-120. or b. PES yarn, non texturised. Width of 165 cm yarn fineness between decitex 70-150 and 40-120 filaments. Elastomeric yarn, yarn fineness between decitex 11-78.
(92) In an another embodiment the top structure can consist of a single knit top layer with raised and recessed areas that can be dot coated to a second layer consisting of a double knit structure that can take up water very well, such like a composition of cotton and polyester.
(93) Single Knit Raised Structure: Gauge 18-50
(94) Raised and recessed areas:
PES yarn, non texturized, yarn fineness between decitex 50-150 and filaments 40-120.
The double faced structure has a material composition consisting of 10-30% cotton fibers and 70-90% PET fibers
(95) Interlock Double Knitted Fabric: Gauge 18-50 Top layer and bottom layer are knitted together
Top layer: 30% of the fabric weight.Cotton. yarn fineness between NM 50-NM 170.
Bottom layer: 70% of the fabric weight. PES, non texturized, yarn fineness decitex 33-150. Filaments 16-150,
(96) Another embodiment of the barrier layer is made from just an open single knit PET structure, which is very smooth and which is foulard coated with a PUR or dendrimer based finish or a venting membrane.
(97) Summary of the Most Preferred Embodiments of the Permanent Stay and Transfer Sheet and Special Versions Thereof are:
(98) 1. A double faced knitted fabric with raised and recessed structures on the top plane made from one type of polymer fiber, either a 3-dimensional knitted jacquard fabric with monofilament yarns and possibly multifilament yarns interconnecting top and bottom layers, or a jacquard single or double knitted fabric without those monofilament or multifilament yarns.
(99) 2. A double faced knitted fabric with raised and recessed structures on the top plane made from one type of polymer yarn, and on the bottom plane made from the same or a different type of polymer yarn, either being a 3-dimensional knitted jacquard fabric with filament yarns and possibly multifilament yarns interconnecting top and bottom layers, or a jacquard single or double knitted fabric without those monofilament or multifilament yarns.
(100) 3. A double faced knitted fabric with raised and recessed structures on the top plane made from one type of polymer yarn, either a 3-dimensional knitted jacquard fabric with monofilament yarns and possibly multifilament yarns interconnecting top and bottom layers, or a jacquard single or double knitted fabric without those, in which the top layer has a larger yarn diameter and less filaments per yarn than the bottom layer which is manufactured of a layer with an equal or smaller diameter and or larger number of filaments. A preferred embodiment has in the top plane raised areas or lines which are interconnected to each other in a continuous fashion and which form gliding lines in at least two directions to limit friction with the skin of a patient. The bottom plane is consisting of a very smooth structure preventing tear and shear forces between the skin of the patient and the top plane due to turning movements of the patient in bed.
(101) 4. The single and double knitted fabrics have raised areas or lines which are interconnected to each other in a continuous fashion and which form gliding lines in at least two directions to limit friction with the skin of a patient.
(102) 5. The preferred embodiments have raised gliding lines in the machine width direction and perpendicular to the stitch wales of the fabric which compensate for the intrinsic diminished gliding characteristics over these stitch wales, which can also be in other directions under smaller or larger angles with the horizontal axis of the fabric.
(103) 6. The preferred embodiments have raised gliding lines in the machine width direction and perpendicular to the stitch wales of the fabric, which compensate for the intrinsic diminished gliding characteristics over these stitch wales, which can be created with the above mentioned gliding lines or areas. Above mentioned gliding characteristics are also obtained by the orientation and positioning of the basic shapes of the raised structures (diamond shape, octagonal, hexagonal, round, oval etc.) and combinations of both.
(104) 7. All preferred embodiments as described above may get a venting and a vapour and gas permeable liquid barrier underneath consisting of a polymer finish applied via a foam or spray process, such as hydrophobic coating, PUR-finishes, fluorocarbon finishes, dendrimer based finished etc.
(105) 8. All preferred embodiments as described above may get a venting and vapour and gas permeable but liquid tight membrane underneath consisting of PET, PUR, nanofibers, PTFE or other type of membrane material.
(106) 9. All preferred embodiments as described above may get a single knit backing layer under a venting and vapour and gas permeable liquid barrier to ensure easy gliding between bottom layer and underlying structures and to protect finishes and coatings
(107) 10. The double knitted two faced fabric can be replaced by a single knit fabric with similar raised and recessed lines and areas, which can, as described under 6 and 7, also be made liquid tight. This single knit layer could be used as direct skin contact layer or as protective layer underneath the permanent stay and transfer double knit fabric as described under embodiments 1, 2, 3, 4, 5, 6.
(108) In the texts below we describe again various possible embodiments of the stay and transfer sheet.
(109) The Different Embodiments of the Stay and Transfer Sheet:
(110) In order to ensure controlled water absorption, proper micro-climate and patient transfer properties of the stay and transfer sheet the following compositions or preferred global embodiments have been considered. The essence of these embodiments is that in all cases the top layer is a double knit elastic layer with raised and recessed areas, either a jacquard knitted two plane layer or a double knit two plane 3-dimensional structure and this layer can be glued via dot coating technique to another membrane type of layer or can itself be treated in such a way that leakage to the underlying mattress is prevented by applying a sprayed or foamed PUR coating to the bottom plane of the double knit fabric and or non-sliding, gluing side of the single knit layer.
(111) Stay and Transfer/Bedsheets Constructions:
(112) a. Passive stay and transfer sheet. An inelastic transfer sheet is needed in order to transfer an immobile patient together with the sheet. The inelasticity is to assure efficient transport by nursing staff.
(113) The top surface being a double knitted textile fabric is dot coated with elastic Hotmelt glue to a PU membrane film blocking water but which is breathable and is allowing vapours and gases to go through. This composition of 2 layers is then dot glue coated (with PU) to a low friction bottom surface, preferably a smooth, low friction single knit fabric of PET-fibers that is guaranteeing low friction transfer, sliding and limits the shear forces drastically. The PU membrane is normally composed of a micro porous film and in this embodiment foreseen with a monolithic membrane that ensures continuous breathability and has limited elasticity. The amount of glue used will limit the overall elasticity in the both horizontal directions of the 3-layer passive transfer and stay sheet and will allow direct pulling and sliding of this sheet on the underlying materials when the patient is on it.
(114) A special embodiment of this passive stay and transfer sheet can be a version which has due to its double knitted structure and number of filaments of fibers, extra moisture absorption capacity for persons who sweat more than moderate or suffer from urine overflow from their incontinence diapers and can be a velours structure with raised and recessed areas or a double knitted two plane structure made of a combination of the last one with a velours layer as described or a two layer double knit jacquard or 3-dimensionals structure with raised and recessed areas on top.
(115) The 1 layer passive stay and transfer double knitted textile fabric is produced on an interlock 8 lock machine with a gauge from 28 to 48, more preferable between 36 and 44. The structure is composed of a 100% PET yarn with a fineness of between 50 and 150 decitex and between 40 and 120 filaments. The interlock knitted structure is modified in such a way that it is limiting the elasticity of the fabric in the width and longitudinal direction to such a limit that the final elasticity is between 3 and max 8%.
(116) b. Active stay and transfer sheet:
(117) An elastic transfer sheet is needed in order to enable a mobile patient to transfer himself on that sheet and/or with assistance of the nursing staff. The top surface being a double knitted textile fabric with two planes that is dot glue coated to a PU membrane blocking water but who is breathable and is letting vapours and gases go through. This PU membrane is dot coated to a low friction bottom surface/backing that is ensuring the protection of the monolithic or polymer membrane and which is preferably an elastic single knit fabric of PET-fibers.
(118) c. Passive transfer stay sheet/3 or 4 layers.
(119) The top surface being a double knitted textile fabric is dot glue coated to a low friction bottom single knit surface to guarantee low shear forces of the stay and transfer sheet on the underlying materials. This low friction bottom surface is treated with a breathable water repellent finish such as PUR finish, a FluorCarbon C6 finish, a dendrimer based finish or a silicone polymer finish and or a membrane, of which the PUR spray or foam finish can be applied on the bottom side of the two plane fabric and on the top side of the single knit fabric enabling a higher barrier function for water vapour.
(120) d. Active transfer stay sheet/3 or 4 Layers. See description under c.
(121) The top surface being a double knitted textile fabric that is dot glue coated to an elastic single/double knit backing. This surface or surfaces can be provided with a breathable water repellent finish and or membrane such as described in embodiment.
(122) e. Special embodiment with a 3D spacer fabric two plane structure.
(123) In one embodiment the permanent active and or passive stay and transfer sheet will consist of a special 3-dimensional double knitted spacer fabric in which top and bottom layers are interconnected through monofilament and or multifilament fibers. The top and bottom layer are very soft and have low friction properties and have different fiber composition with a lower number of filaments on top than at the bottom and an equal or higher single filament diameter at the top surface.
(124) On the top surface a raised structure is created in the (circular) knitting process by the creation of tuck stitches, which are 2-3 times longer than the regular knitting loops of the multifilament fiber and which are pulled tighter creating a raised rim or line. The bottom layer of this embodiment but also of embodiments a, b, c, d can be produced with the laminating/coating of a monolithic membrane or special membranes/finishes as described below. The top layer has a mini raised grid structure with raised and recessed areas to reduce skin frictions. Between the top- and under layer small also square, rectangular or diamond shaped sections of monofils can be produced that are surrounded on all sides with open areas without monofils, which result in better tri axial elastic, elongation and independent resilience properties. These sections can adapt their individual pressure reducing capacity to the changing forms/contours of the human body and the different cold- and memory foam mattress. The bottom layer has a structure of smooth non texturized fibers so that it can distribute pressure forces to the under laying mattress structures.
(125) f. Another embodiment of the invention is in x and y directions elastic cover sheet with a smooth top layer and breathable membrane layer beneath it, serving as cover for the Mini mattress and allowing the stay and transfer sheet to reduce the shear and friction forces that occur when the patient is laying on it. The top layer of the coversheet is produced on a single knit machine with a gauge between 22 till 44 more preferable between 26 till 36 This single knit is based on a pique structure is made from PET yarns and specific percentage of elastomeric yarns and is dot coated to a breathable PU membrane between 10 and 40 micron meter thick. The composition assures protection of the mini mattress and allowing ventilation of vapours and through its elasticity enhances the pressure reduction process.
(126) g. Another embodiment of the barrier layer is made from an open single knit PET structure, which is very smooth and foreseen with a PU finish or dendrimer based finish or coating, which can fulfil a function as a barrier and gliding layer h. Single plane circular knitted passive stay and transfer layer, consisting of a double knit circular knitted fabric with limited elasticity via the so called interlock system and with raised lines or surfaces on top and or bottom surface. Both sides of the product are knitted with a very smooth PET yarn.
(127) Composition of Membranes and Finishes:
(128) As described on previous pages we consider the necessity of using a water blocking layer in the construction, which is nevertheless permeable to gases and vapours. For this we can use the following solutions, which are not limited to these solely. 1. Elastic Polyurethane membrane (monolithic, porous) 2. Non elastic Polyurethane membrane (monolithic, porous) 3. PTFE Membrane, also inelastic versions 4. Nanofiber membranes. Through electro spinning of nano fibres a nonwoven layer of 50-100 micron is produced allowing breathability and blocking liquid passage. 5. Silicon polymer based finish 6. Polyurethane coating, e.g. Purtex. Via spray or foam or foulard systems a PUR coating can be applied upon the textile surface layer. This coating guarantees breathability and blocks water. 7. PUR direct coating on the textile layer in wet condition via spray, foam or foulard treatment. 8. Foulard, spray or foam applied finishes with dendrimer or other nanomaterial based solutions to prevent water drops from entering the fabric. A smart textile solution to facilitate permanent and long time staying in wheelchairs, chairs and on beds of chronically ill, less mobile and immobile patients especially in the elderly care, nursery care, rehabilitation and homecare in the embodiment of a textile based stretchable stay and transfer layer which can cover mattresses and cushions. Technical solutions within the invention are provided to guarantee a dry skin and to control the temperature thereof, the so called control of the micro climate, to lower and evenly distribute pressures and shear forces, and moreover to enable an easy low friction movement of patients in bed or in sitting positions, and to enable transfers into the bed and transfers out of the bed.