Bonding of structures

DETAILED DESCRIPTION What we claim is: 1.
A method of bonding a non-woven structure comprising at least one thermoplastic material in a predetermined pattern of spaced bond-points which comprises forming a pressure nip formed by a plurality of members at least one of which is a bonding roll provided with projections on its surface, said bonding roll in co-operation with a backing roll, heating said bonding roll to a temperature below the softening point of said thermoplastic material, passing said non-woven structure through the pressure nip, compressing said web between said bonding roll and said backing roll, raising the temperature of said projections and said web to a temperature above the temperature of the remainder of said bonding roll by work done by said projections to compress said web, said bonding roll providing (i) from 50 to 1000 bond points per square inch of said web, (ii) said bond points having bases with a cross sectional area of from 1.
times.
10.
sup.
-.
sup.
5 square inch to 1.
times.
10.
sup.
-.
sup.
3 square inch, (iii) the bases of said bond points lying at a debth of from 50% to 98% of the thickness of said web, (iv) said bond points having an interface angle of from 1.
degree.
to 60.
degree.
, (v) said bond points occupying from about 1% to 20% of the total area of said web, simultaneously avoiding contacting said web with the surface of said bonding roll between said projections and substantially avoiding bonding between said bond points, and withdrawing said web as a bonded non-woven structure.
2.
The process of claim 1, wherein the area between bonds is compacted to a density of less than four times the initial density of said non-woven structure.




Description:
BACKGROUND The invention relates to novel and improved non-woven structures and methods and apparatus for producing such structures and is particularly concerned with bonded non-woven fabrics having a predetermined pattern of spaced bonded area separated by substantially unbonded areas.
Many attempts to produce non-woven fabrics having good handle, drapeability, strength and abrasion resistance are known