Fibrous material and method of making the same using thermoplastic synthetic wood pulp fibers

A method of producing a high loft, low density, nonwoven fibrous material containing thermoplastic synthetic wood pulp fibers as one constituent thereof and fibrous material other than thermoplastic synthetic wood pulp fibers, said thermoplastic synthetic wood pulp fibers having a length and denier generally similar to natural wood pulp fibers, which comprises:

• applying heat in the absence of pressure to a starting layer of irregularly arranged, intersecting, overlapping, mechanically interengaged, loosely assembled fibers including both said synthetic wood pulp fibers and fibers other than synthetic wood pulp fibers, said fibrous material contains generally in the range of about 10 percent to about 30 percent by weight of said synthetic wood pulp fibers, the general orientation and arrangement of the fibers of said material being substantially the same in all directions across the material and substantially uniform from one boundary surface of the material to the other, said other fibers having a melting point, or degradation temperature, above that of the temperature of the synthetic wood pulp fibers, to fuse at least some of said synthetic wood pulp fibers to each other and to some of said other fibers and thereby form a self-supporting fibrous web in the absence of any additional binder which is resistant to web collapse during the subsequent bonding step;
• introducing a liquid binder into said fibrous web;
• and
• drying and curing said binder to bond fiber segments in contact with each other throughout the web to form a stable bonded fibrous material of good wet strength, abrasion resistance and delamination resistance with substantially lower density and less shrinkage stiffness and harshness than would be exhibited by a fibrous web formed of said other fibers alone and with its fibers bonded only by said binder.