Spacer fabrics and methods of making the same

Abstract

A spacer fabric and methods of making the same comprising: knitting first and second yarns to form a knit structure, the first yarn defining mirror image knit and tuck patterns on at least the first and second courses and the second yarn defining mirror image knit and miss patterns on at least the third and fourth courses to comprise a plurality of concave portions in facing opposition to a plurality of convex portions, the concave and convex portions defining void spaces having a substantially double convex cross section, wherein the first yarn has low thermal shrinkage and the second yarn has high thermal shrinkage, and heating the knit structure at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension wherein the second yarn shrinks more than the first yarn in the at least one dimension when heating the knit structure.

What is claimed is: 
     
         1 . A method of making a spacer fabric comprising:
 knitting a first yarn and a second yarn to form a knit structure, the first yarn defining a knit and tuck pattern on at least a first course and a mirror image pattern on at least a second course and the second yarn defining a knit and miss pattern on at least a third course and a mirror image on at least a fourth course, wherein the knit structure comprises a plurality of concave portions in facing opposition to a plurality of convex portions, the concave portions and the convex portions defining void spaces having a substantially double convex cross section, and wherein the first yarn is a low thermal shrinkage yarn and the second yarn is a high thermal shrinkage yarn; and   heating the knit structure at a temperature sufficient to cause the second yarn to shrink by at least 10% in at least one dimension wherein the second yarn shrinks more than the first yarn in the at least one dimension during the step of heating the knit structure.   
     
     
         2 . The method of  claim 1  wherein the second yarn shrinks by 10% to 90% in the at least one dimension during the step of heating the knit structure based on an original size of the second yarn in the at least one dimension prior to the step of heating the knit structure. 
     
     
         3 . The method of  claim 1  wherein the second yarn shrinks at least two times as much as the first yarn in the at least one dimension during the step of heating the knit structure. 
     
     
         4 . The method of  claim 1  wherein the step of heating the knit structure increases a size of the void spaces in a thickness direction of the fabric. 
     
     
         5 . The method of  claim 1  further comprising at least a third yarn, said at least third yarn defined in at least a fifth course having a knit, miss, or tuck pattern and at least a sixth course having a mirror image of the fifth course, and wherein upon heating, the third yarn is a thermally fusible yarn which melts at the heated temperature and binds the adjacent yarns in the double convex structure. 
     
     
         6 . The method of  claim 1  wherein the first yarn is selected from the group consisting of: a monofilament yarn, a monocomponent monofilament yarn, and a multicomponent monofilament yarn. 
     
     
         7 . The method of  claim 1  wherein the first yarn has a higher modulus than the second yarn. 
     
     
         8 . The method of  claim 1  wherein the second yarn is a monocomponent multifilament yarn or a multicomponent multifilament yarn. 
     
     
         9 . The method of  claim 1  wherein after heating, the spacer fabric comprises a plurality of zones having different compression resistances in a thickness direction of the fabric defined by modifying the knit structure or the yarn in the different zones. 
     
     
         10 . The method of  claim 9  wherein the spacer fabric has one or more first zones of low compression resistance and one or more second zones of high compression resistance. 
     
     
         11 . The method of  claim 10  wherein the first zones have a compression resistance of no more than 30 psi and the second zones have a compression resistance of at least 50 psi. 
     
     
         12 . A spacer fabric comprising:
 a knit structure formed from a first yarn having a low thermal shrinkage and a second yarn having a higher thermal shrinkage than the first yarn, wherein the first yarn comprises a knit and tuck pattern on a first course and a mirror image of the knit and tuck pattern on a second course, wherein the second yarn comprises a tuck and miss pattern on a third course and a mirror image on a fourth course, and wherein the mirror images of each of the first, second, third, and fourth courses are positioned on a front needle bed or a back needle bed; and   wherein upon heating of the knit structure, the high shrinkage yarn shrinks to form a plurality of concave portions forming a sinusoidal shape in facing opposition to a plurality of opposing convex portions, the concave portions and the opposing convex portions defining void spaces having a substantially double convex cross section.   
     
     
         13 . The spacer fabric of  claim 12  wherein the knit structure is a unitary knit structure. 
     
     
         14 . The spacer fabric of  claim 12  wherein the second yarn shrinks at least twice as much as the first yarn in at least one dimension at a heat shrinking temperature between 50° C. and 150° C. 
     
     
         15 . The spacer fabric of  claim 12  wherein heating the knit structure at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension increases a size of the void spaces in a thickness direction of the fabric. 
     
     
         16 . The spacer fabric of  claim 12  wherein a thickness of the fabric increases by at least 0.5 cm when the fabric is heated at a temperature sufficient to cause shrinkage of the second yarn by at least 10% in at least one dimension. 
     
     
         17 . The spacer fabric of  claim 12  further comprising a third yarn, said third yarn being a thermally fusible yarn, wherein the thermally fusible yarn is positioned within a knit, tuck, or miss pattern on a fifth course and a mirror image on a sixth course, and wherein after heating of the fabric to a temperature sufficient to melt the thermally fusible yarn, the thermally fusible yarn melts and fuses with the first and second yarns. 
     
     
         18 . The spacer fabric of  claim 12  further comprising a knit transition zone. 
     
     
         19 . The spacer fabric of  claim 12  wherein a knit pattern comprises between 6 and 24 courses in one direction and between 6 and 48 needles in another direction to define the knit structure of the fabric. 
     
     
         20 . A spacer fabric comprising:
 a knit structure formed from a first yarn having a low thermal shrinkage and a second yarn having a higher thermal shrinkage than the first yarn, wherein the first yarn comprises a knit and tuck pattern defined within a front needle bed, a back needle bed, or both on a first course and a mirror image of the knit and tuck pattern on a second course and wherein the second yarn comprises a tuck and miss pattern on a third course and a mirror image on a fourth course, wherein the mirror images of each of the first, second, third, and fourth courses are defined in relation to the front needle bed or the back needle bed of each course, and a third yarn, being a thermally fusible yarn, having a pattern comprised of knit, tuck, or miss stitches along a fifth course and a mirror image on a sixth course; and   wherein upon heating of the knit structure, the high shrinkage yarn shrinks to form a plurality of concave portions in facing opposition to a plurality of opposing convex portions, the concave portions and the opposing convex portions defining void spaces having a substantially double convex cross section, and the thermally fusible yarn fuses the structure defined by the first, second, and third yarns.