Process for pattern drawing of webs

Claim 1

A method of differentially drawing a web with a quilted pattern of drawn areas surrounding undrawn islands to increase the strength of the web comprising the steps of providing a web having at least some cold drawable orientable thermoplastic material drawable at cold drawable temperature and providing first and second pairs of meshing gears having a tooth form of one of involute and cycloidal and a pressure angle of between 5° and 40° and a circular pitch less than the product of the web thickness times one hundred with the gear teeth providing rolling contact of the teeth at the pitch circles to provide incremental and simultaneous squeezing and stretching of the web at multiple points on the web between meshing teeth along a line of action for more than one tooth and the teeth of said second pair of gears being at a transverse angle relative to the teeth of the first pair of gears, moving a web through the first gear pair to provide parallel and alternate cold stretched and unstretched zones and moving the web through the second set of meshing toothed rollers at the speed of the teeth of the rollers to superimpose a second pattern on the web having alternate cold stretched and unstretched zones to provide generally quadrilaterally shaped undrawn islands bounded fully on each of their four sides by an axially drawn molecularly oriented area and each quadrilateral island being contiguous at each of its four apices to a biaxially drawn molecularly oriented area.

Claim 2

A method of differentially drawing a web with a quilted pattern of drawn areas surrounding undrawn islands to increase the strength of the web comprising the steps of providing a web having at least some cold drawable orientable thermoplastic material drawable at cold drawable temperature and providing first and second pairs of meshing gears having a tooth form of one of involute and cycloidal and a pressure angle of between 5° and 40° and a circular pitch less than the product of the web thickness times one hundred with the gear teeth providing rolling contact of the teeth at the pitch circles to provide incremental and simultaneous squeezing and stretching of the web at multiple points on the web between meshing teeth along a line of action for more than one tooth and the teeth of said second pair of gears being at a transverse angle relative to the teeth of the first pair of gears, moving a web through the first gear pair to provide parallel and alternate cold stretched and unstretched zones and moving the web through the second set of meshing toothed rollers at the speed of the teeth of the rollers to superimpose a second pattern on the web having alternate cold stretched and unstretched zones to provide generally quadrilaterally shaped undrawn islands bounded fully on each of their four sides by an axially drawn molecularly oriented area and each quadrilateral island being contiguous at each of its four apices to a biaxially drawn molecularly oriented area.

Claim 7

A method of differentially cold drawing at a temperature below its melting range a web having at least in part cold drawable polymeric material comprising the steps of providing a set of meshing toothed gears to incrementally squeeze the web between meshing teeth along a line of action for more than one tooth to cold draw part of said web and wherein the relative tooth height of the teeth on the gears is between 5 and 15 and wherein the relative tooth height is equal to the tooth height in inches divided by the original undrawn web thickness in inches, and moving the web through the rollers to form a pattern of substantially parallel undrawn areas alternating with parallel axially drawn areas.

Claim 8

A method of differentially cold drawing at a temperature below its melting range a web having at least in part cold drawable polymeric material comprising the steps of providing a set of meshing toothed gears to incrementally squeeze the web between meshing teeth along a line of action for more than one tooth to cold draw part of said web and wherein the relative tooth height of the teeth on the gears is between 5 and 15 and wherein the relative tooth height is equal to the tooth height in inches divided by the original undrawn web thickness in inches, and moving the web through the rollers to form a pattern of substantially parallel undrawn areas alternating with parallel axially drawn areas.

Claim 14

A method of differentially cold drawing a web having at least in part cold drawable polymeric material with a quilted pattern of drawn areas surrounding undrawn islands comprising the steps of providing multiple pairs of meshing toothed gears with at least one set of gears having a tooth form to provide rolling contact of the teeth at the pitch circles to provide incremental squeezing and stretching of the web between meshing teeth along a line of action for more than one tooth to cold draw part of said web below its softening point and the teeth being at a transverse angle relative to the teeth of another set of rollers, moving a web through the pairs of gears to provide the web with generally polygonal shaped undrawn islands bounded on some of their sides by cold drawn areas.

Claim 15

A method of differentially cold drawing a web having at least in part cold drawable polymeric material with a quilted pattern of drawn areas surrounding undrawn islands comprising the steps of providing multiple pairs of meshing toothed gears with at least one set of gears having a tooth form to provide rolling contact of the teeth at the pitch circles to provide incremental squeezing and stretching of the web between meshing teeth along a line of action for more than one tooth to cold draw part of said web below its softening point and the teeth being at a transverse angle relative to the teeth of another set of rollers, moving a web through the pairs of gears to provide the web with generally polygonal shaped undrawn islands bounded on some of their sides by cold drawn areas.

Claim 18

A method of differentially drawing a web with a quilted pattern of cold drawn areas surrounding undrawn islands comprising the steps of providing a web having at least in part cold drawable polymeric material drawing the web in a first direction and providing a pair of meshing gears having a tooth form to provide rolling contact of the teeth at the pitch circles to provide incremental squeezing and cold stretching of the web while below a heat softened state between meshing teeth along a line of action for more than one tooth wherein the relative tooth height of the teeth on the gears is between 2 and 29 and wherein the relative tooth height is equal to the tooth height in inches divided by the original undrawn web thickness in inches and the teeth being at a transverse angle relative to the direction of draw in the first direction and moving a web through the gears to provide stretched and unstretched zones including generally polygonal shaped undrawn islands.

Claim 19

A method of differentially drawing a web with a quilted pattern of cold drawn areas surrounding undrawn islands comprising the steps of providing a web having at least in part cold drawable polymeric material drawing the web in a first direction and providing a pair of meshing gears having a tooth form to provide rolling contact of the teeth at the pitch circles to provide incremental squeezing and cold stretching of the web while below a heat softened state between meshing teeth along a line of action for more than one tooth wherein the relative tooth height of the teeth on the gears is between 2 and 29 and wherein the relative tooth height is equal to the tooth height in inches divided by the original undrawn web thickness in inches and the teeth being at a transverse angle relative to the direction of draw in the first direction and moving a web through the gears to provide stretched and unstretched zones including generally polygonal shaped undrawn islands.