Compressively treating flexible sheet materials

A method of longitudinal compressive treatment of a sheet material, the method comprising:

• providing a continuous web of said material;
• providing an apparatus comprising:
• a cylindrical drive roll for advancing the web,
• a smooth-surfaced primary member arranged over the drive roll to press the web into driven engagement with the drive roll, and
• a generally-stationary retarder downstream of said primary member positioned to engage and retard the web before the web has left said drive roll, said retarder defining
• an initially-effective retarder surface facing the web, comprising a large multiplicity of parallel ridges and grooves in a set extending across the width of the web to be treated, the ridges and grooves being uniformly biased at an angle to the direction of drive of the web, said ridges and grooves being effective to longitudinally compress the web and to orient the web to flow at a flow angle to the original direction of drive of the web induced by said drive roll, and
• a reorienting retarding surface disposed to be effective after an incremental advance of the web at said flow angle, said reorienting retarding surface constructed to have a supplementary retarding effect that is cooperative with said drive roll to reorient the travel of the web to a direction generally parallel to said original direction of drive;
• and
• passing the web through said apparatus to treat said web.

A method for manufacture of knit fabric, comprising the steps:

• knitting yarn into a knit tube;
• processing said knit tube in a processing line that includes apparatus to slit said knit tube into a flat configuration, wherein as a by-product of said processing, said web is deformed to have variations in density across its length and width;
• processing said deformed web in a microcreping apparatus comprising:
• a cylindrical drive roll for advancing the web,
• a smooth-surfaced primary member arranged over the drive roll to press the web into driven engagement with the drive roll, and
• a generally-stationary retarder downstream of said primary member positioned to engage and retard the web before the web has left said drive roll, said retarder defining
• an initially-effective retarder surface facing the web, comprising a large multiplicity of parallel ridges and grooves in a set extending across the width of the web to be treated, the ridges and grooves being uniformly biased at an angle to the direction of drive of the web, said ridges and grooves being effective to longitudinally compress the web and to orient the web to flow at a flow angle to the original direction of drive of the web induced by said drive roll, and
• a reorienting retarding surface disposed to be effective after an incremental advance of the web at said flow angle, said reorienting retarding surface constructed to have a supplementary retarding effect that is cooperative with said drive roll to reorient the travel of the web to a direction generally parallel to said original direction of drive;
• said microcreping processing effective to reduce the variation of density of said web across its length and width.