Reticular structure derived from film and method of manufacturing said structure

Claim 1

A method of manufacturing a recticular sheet comprised of relatively long and thick, parallel, uniaxially oriented stemfibers and relatively short and thin intervening branchfibers integral with said stemfibers, said branchfibers being biaxially oriented and generally film-sjaped in the regions thereof adjacent to the stemfibers and generally uniaxially oriented and more fibershaped in the other regions, said process comprising the steps of producing in a generally unoriented polymer film a pattern of alternating relatively thick elongated striations and relatively thin intervening bands, said striation and bands extending continuously across the film with their lengthwise direction making an angle in the range from a few degrees to about 90° relative to the longitudinal direction of said film; advancing the striated film in a lengthwise direction to a holding-back means engaging the film generally parallel to the striation angle, removing the film from said means along a path which is deflected transversely from said initial direction of advance at an angle which is sufficiently small to produce a substantial reduction in film width while drawing the film at a ratio of at least about 3.5:1, thereby to stretch and uniaxially orient said thin bands while said thick striations undergo bodily lengthwise displacement relative to one another without stretching; splitting the oriented intervening bands into uniaxially oriented branchfibers while maintaining said striations substantially intact and unoriented; and finally stretching said striations generally in the direction of their length to orient the same generally uniaxially in said direction, so as to form said striations into uniaxially oriented stemfibers, and simultaneously impart biaxial orientation to said branchfibers in the areas thereof adjacent to the stemfibers.

Claim 2

A method of manufacturing a recticular sheet comprised of relatively long and thick, parallel, uniaxially oriented stemfibers and relatively short and thin intervening branchfibers integral with said stemfibers, said branchfibers being biaxially oriented and generally film-sjaped in the regions thereof adjacent to the stemfibers and generally uniaxially oriented and more fibershaped in the other regions, said process comprising the steps of producing in a generally unoriented polymer film a pattern of alternating relatively thick elongated striations and relatively thin intervening bands, said striation and bands extending continuously across the film with their lengthwise direction making an angle in the range from a few degrees to about 90° relative to the longitudinal direction of said film; advancing the striated film in a lengthwise direction to a holding-back means engaging the film generally parallel to the striation angle, removing the film from said means along a path which is deflected transversely from said initial direction of advance at an angle which is sufficiently small to produce a substantial reduction in film width while drawing the film at a ratio of at least about 3.5:1, thereby to stretch and uniaxially orient said thin bands while said thick striations undergo bodily lengthwise displacement relative to one another without stretching; splitting the oriented intervening bands into uniaxially oriented branchfibers while maintaining said striations substantially intact and unoriented; and finally stretching said striations generally in the direction of their length to orient the same generally uniaxially in said direction, so as to form said striations into uniaxially oriented stemfibers, and simultaneously impart biaxial orientation to said branchfibers in the areas thereof adjacent to the stemfibers.

Claim 12

A method of manufacturing a recticular sheet comprised of relatively long and thick, parallel, uniaxially oriented stemfibers and relatively short and thin intervening branchfibers integral with said stemfibers, said branchfibers being biaxially oriented and generally film-shaped in the regions thereof adjacent to the stemfibers and generally uniaxially oriented and more fibershaped in the other regions, said process comprising the steps of producing in a generally unoriented polymer film a pattern of alternating relatively thick elongated striations and relatively thin intervening bands, said striation and bands extending continuously across the film with their lengthwise direction making an angle in the range from a few degrees to about 90° relative to the longitudinal direction of said film; advancing the striated film in a lengthwise direction to a holding-back means engaging the film generally parallel to the striation angle; removing the film from said means along a path which is deflected transversely from said initial direction of advance at an angle relative to said holding-back locus which is smaller than the angle of said locus relative to said advance direction, whereby the deflected film undergoes a reduction in width, while drawing the film at a ratio of at last about 3.5:1 to stretch and uniaxially orient said thin bands while said thick striations undergo bodily lengthwise displacement relative to one another without stretching; advancing the thus selectively stretched film on said deflected path to a second holding-back means engaging said film generally parallel to said striations; removing said film from said second means along a path which is further deflected from said deflected path at an angle generally reverse to said first deflection angle and sufficiently great to increase the film width and thus split the oriented intervening bands while said striations ungergo bodily lengthwise relative displacement in a generally reverse direction and remain intact; and finally stretching the entire film in the lengthwise direction of said striations to orient the same generally uniaxially in said direction, so as to form said striations into uniaxially oriented stemfibers, and simultaneously impart biaxial orientation to said branchfibers in the areas thereof adjacent to the stemfibers.

Claim 13

A method of manufacturing a recticular sheet comprised of relatively long and thick, parallel, uniaxially oriented stemfibers and relatively short and thin intervening branchfibers integral with said stemfibers, said branchfibers being biaxially oriented and generally film-shaped in the regions thereof adjacent to the stemfibers and generally uniaxially oriented and more fibershaped in the other regions, said process comprising the steps of producing in a generally unoriented polymer film a pattern of alternating relatively thick elongated striations and relatively thin intervening bands, said striation and bands extending continuously across the film with their lengthwise direction making an angle in the range from a few degrees to about 90° relative to the longitudinal direction of said film; advancing the striated film in a lengthwise direction to a holding-back means engaging the film generally parallel to the striation angle; removing the film from said means along a path which is deflected transversely from said initial direction of advance at an angle relative to said holding-back locus which is smaller than the angle of said locus relative to said advance direction, whereby the deflected film undergoes a reduction in width, while drawing the film at a ratio of at last about 3.5:1 to stretch and uniaxially orient said thin bands while said thick striations undergo bodily lengthwise displacement relative to one another without stretching; advancing the thus selectively stretched film on said deflected path to a second holding-back means engaging said film generally parallel to said striations; removing said film from said second means along a path which is further deflected from said deflected path at an angle generally reverse to said first deflection angle and sufficiently great to increase the film width and thus split the oriented intervening bands while said striations ungergo bodily lengthwise relative displacement in a generally reverse direction and remain intact; and finally stretching the entire film in the lengthwise direction of said striations to orient the same generally uniaxially in said direction, so as to form said striations into uniaxially oriented stemfibers, and simultaneously impart biaxial orientation to said branchfibers in the areas thereof adjacent to the stemfibers.