US 4,834,838 A · Fibrous tape base material

Abstract

A sheet of fibrous web material having opposite smooth surfaces, an apparent bulk in the range of about 0.10 to about 0.20 caliper pts/lb ream and a machine direction stretch of at least 8%, wherein surface undulations on the opposite smooth surfaces of the sheet have an amplitude variance of less than 0.0002 inch. The invention includes an apparatus and a method of manufacturing the product comprising partially dewatering a wet fibrous web to about 30% to 50% solids, conveying the web to a compression nip defined by a smooth-surfaced roll and a smooth-surfaced fabric material, moving the fabric material at a speed of about 10% to 20% less than the surface speed of the smooth-surfaced roll, compressing the web in the nip with a compression force of less than 15 lbs/linear inch, with an average pressure of less than about 50 psi in the compression nip, and drying the web. The dried web has an apparent bulk less than 0.20 caliper pts/lb ream.

Claims26

Dependent claims

A method of manufacturing a stretchable fibrous tape base material having surfaces with improved surface smoothness, comprising the steps of:

(a) forming a wet fibrous web;
(b) partially dewatering the web to between about 30% and about 50% solids;
(c) conveying the partially dewatered web on a smooth-surfaced roll to a compression nip defined by the smooth-surfaced roll and a smooth-surfaced fabric material;
(d) moving said fabric material at a speed of about 10% to about 20% less than the surface speed of said smooth-surfaced roll;
(e) compressing said web in said nip by forcing said fabric material against said web on said smooth-surfaced roll to directly transfer said web from said roll to said material, said fabric material being compressed against said web with a compression force of less than 15 lbs/linear inch and the average pressure is less than 50 psi in the compression nip, said web being further compressed in the machine direction by the difference in speed between said fabric material and the surface of said roll;
and
(f) drying said web, said dried web having an apparent bulk less than 0.20 caliper pts/lb ream.

4 more elements

An apparatus for manufacturing a stretchable fibrous base web having opposite surfaces with improved smoothness and reduced apparent bulk, comprising:

means for forming a wet fibrous web;
dewatering means for partially dewatering said web to between about 30% and about 50% solids;
a smooth-surfaced roll having an outer circumferential surface for conveying the dewatered web at a predetermined speed to a transfer station;
first and second support rollers, each having an outer circumferential surface, positioned on opposite machine direction sides of said transfer station, said support rollers being disposed along a linear path corresponding to a line passing through the transfer station, said line being tangent to the outer circumferential surfaces of the first and second support rollers and the outer circumferential surface of the smooth-surfaced roll;
a sheet of fabric material for receiving the web at said web transfer station and for conveying the web from the transfer station at a speed less than said predetermined speed, said sheet of fabric material being supported along said linear path between said first and second support rollers substantially coincident with said line;
compression means for applying a compression force at the transfer station of less than 15 lbs/linear inch on said web through said sheet of fabric material for transferring said web from said smooth-surfaced roll to said sheet of fabric material, and for compressing said web to adjust the apparent bulk of said web;
and
means for drying said web after compression, said dried web having an apparent bulk of less than 0.20 caliper pts/lb ream.

5 more elements

Dependencies are inferred from the claim text.

Fibrous tape base material

Life of this patent

Fibrous tape base material

Life of this patent

Abstract

Claims26