Process for manufacturing nonwoven web material
A nonwoven web material including fibers formed of a polyolefin and a polyester is disclosed. The fibers may include fine fibers produced by, for example, a meltblowing process. The polyolefin may be polypropylene and the polyester may be polylactic acid. The polylactic acid may be obtained and included by recycling scrap nonwoven material containing a polylactic acid component, hydrolyzing the polylactic acid component to reduce its viscosity, blending the hydrolyzed polylactic acid with a polyolefin resin, and melt-spinning the blended material to form fibers. A related process is disclosed.
1. A process for manufacturing a nonwoven web including recycled material, comprising the steps of:
spinning spunbond fibers comprising polylactic acid and polypropylene, and accumulating the spunbond fibers to form a first deposited layer;
spinning monocomponent fine fibers having an average diameter of 0.10 μm to 10 μm from meltblowing resin comprising virgin polypropylene resin, and accumulating the fine fibers to form a second deposited layer;
joining the first deposited layer and the second deposited layer to form a layer combination;
calender bonding the layer combination to form a nonwoven web;
collecting scrap material comprising portions of the nonwoven web;
mechanically dividing the scrap material;
hydrolyzing polylactic acid contained in the divided scrap material to form recyclable scrap material;
blending the recyclable scrap material with the meltblowing resin during said fine fibers spinning step, and thereby recycling the scrap material.
2. The process of claim 1 , wherein the spunbond fibers spinning step further comprises spinning bicomponent spunbond fibers, wherein polylactic acid forms a first fiber component and polypropylene forms a second fiber component.
3. The process of claim 2 wherein the bicomponent spunbond fibers have a core/sheath configuration wherein a core section thereof comprises polylactic acid.
4. The process of claim 1 further comprising the step of vis-breaking polypropylene contained in the scrap material prior to said blending step.