Process for making plastics mesh structures

Claim 2

A process for making plastics flat or tubular mesh structures and other forms of openwork, such process comprising the steps of: extruding a plurality of continuous filaments parallel to the direction of extrusion and transversely spaced apart, and separately extruding, periodically and transversely of the continuous filaments, strands that are discontinuous in a transverse direction and extend across less than all of the plurality of filaments, each strand being of a length at least equal to the spacing between two adjacent filaments, whereafter the strands are thrust toward the filaments so as to be welded to the filaments.

Claim 3

A process according to claim 1, wherein successive rows of discontinuous transverse strands are extruded on alternate sides of the plurality of continuous filaments, the rows being spaced apart in the direction of extrusion and the strands being in length substantially equal to the spacing between two adjacent filaments, the strands of each row being positioned opposite alternate spaces between the filaments and successive rows also being positioned opposite alternate spaces between the filaments, the strands being pressed between the continuous filaments so as to weld the strands at their ends to the filaments.

Claim 4

A process according to claim 1, wherein two rows of discontinuous transverse strands are extruded simultaneously, one on each side of the plurality of continuous filaments, the strands being in length substantially equal to the spacing between two adjacent filaments, the strands of each row being disposed opposite alternate spaces between the filaments and the two rows of strands also being positioned opposite alternate spaces between the filaments, and wherein all the extruded strands of the two rows are thrust simultaneously into all the spaces between the continuous filaments to weld the strands at their ends to the filaments.

Claim 5

A process according to claim 1, wherein: a first row of discontinuous aligned transverse strands longer than the spacing between two adjacent filaments is extruded periodically on one side of the plurality of filaments, and a second row of discontinuous aligned transverse strands longer than the spacing between two adjacent filaments is extruded periodically on the other side of the plurality of filaments, the first row of extruded strands being thrust onto the continuous filaments so as to position each transverse strand on at least two adjacent continuous filaments and on less than all the filaments, the second row of extruded strands being thrust onto the continuous filaments so as to place each transverse strand of the second row on at least two adjacent continuous filaments not joined together by a strand of the first row.

Claim 6

A process according to claim 4, wherein the second row of discontinuous aligned transverse strands is extruded periodically so as to be offset from the first row of strands in the direction of extrusion.

Claim 7

A process according to claim 1, wherein successive rows of discontinuous aligned transverse strands are extruded on just one side of the plurality of continuous filaments opposite the spaces therebetween and are spaced apart in the direction of extrusion, and wherein the extruded strands of one row are thrust into some of the spaces between the continuous filaments and the extruded strands of an immediately succeeding row are thrust into the remaining spaces between the continuous filaments to weld the strands at their ends to the filaments.

Claim 8

A process according to claim 1, wherein successive rows of aligned discontinuous transverse strands are extruded on just one side of the plurality of continuous filaments opposite the spaces therebetween and wherein the strands of each row are all thRust simultaneously into all the spaces between the continuous filaments to connect the strands at their ends to the filaments.

Claim 9

A process according to claim 1, wherein the extruded mesh structure is given a simultaneous two-directional drawing and cooling treatment.

Claim 10

A process according to claim 7, wherein the discontinuous strands have greater mechanical strength transversely than the transverse strength of the continuous filaments before two-directional drawing.