Recyclable bale wrap made from a thermally bonded, needlepunched, polyester nonwoven

A non-woven recyclable polyester fabric suitable for use as a bale covering that is a single layer batt formed of crosslapped fiber having a structure compacted by needlepunching and calendering. A process for producing this non-woven recyclable polyester fabric that includes forming a web of fiber, crosslapping the web to form a batt, needlepunching the batt, and calendering the batt under suitable conditions.

BACKGROUND OF THE INVENTION 
The present invention is directed to the field of non-woven fabrics in 
general and is directed to a single layer non-woven recyclable polyester 
fabric suitable for use as bale covering having high strength and 
resistance to tears and abrasion and to which labels can stick. The fabric 
of the present invention can be recycled. The present invention is also 
directed to a process for producing such a non-woven fabric. 
For many years fiber producers have sought a solution to the problem of 
wrapping bales of fibers to protect the fibrous material from 
contamination and damage during shipping. Some wraps commonly used are 
jute or burlap. Other wraps include polypropylene. Such wraps require 
disposal in landfills. 
Other wraps include woven polypropylene, the predominant bale wrapping 
material. These wraps however, fibrillate in use, the polypropylene 
strands becoming closely entwined with the fibers, and thereby 
contaminating it. Such contamination cannot be separated and is extremely 
difficult to detect in raw fibers. Moreover, polypropylene wraps are not 
biodegradable or recyclable and have few end uses. An example of this type 
of woven wrap is disclosed in U.S. Pat. No. 4,557,958 (Barkis) wherein 
woven polypropylene or polyethylene fabric is infused with a series of 
stripes of thermoplastic resin to prevent fraying when the fabric is cut. 
U.S. Pat. No. 5,104,703 (Rachman et al) discloses a single layer non-woven 
fabric suitable for use as a cotton bale covering that is a single layer 
batt formed of a blend of fibers including polyester and low melt 
thermoplastic fibers such as bicomponent fibers. As will be shown, the 
present invention exhibits superior products to the blend of the polyester 
fibers and the binder fibers. 
It is a primary object of this invention to provide a recyclable polyester 
bale cover usable for fiber materials. 
A further object of this invention is the provision of a new type of single 
layer non-woven recyclable fabric suitable for use as polyester bale 
covering, wherein a combination of needle punching and calendering lend 
high strength to the fabric. 
It is a further object of this invention to provide a non-woven single 
layer recyclable polyester fabric that does not fibrillate in use as do 
woven polypropylene bale wrapping materials. 
Still another object is to provide a non-woven single layer recyclable 
polyester fabric that provides greater resistance to tears, rips and holes 
over conventional woven polypropylene bale wrapping materials. 
A further object is to provide a non-woven single layer recyclable 
polyester fabric that is comparable in cost to polypropylene wraps. 
Still another object of the present invention is to provide a non-woven 
polyester fabric that is recyclable. The fabric can be used in polyester 
bale wrap. Recyclability of the wrap is further enhanced with the use of 
polyester labels. 
SUMMARY OF THE INVENTION 
These and other objects of the invention are achieved by provision of a 
non-woven polyester recyclable fabric comprising a batting of crosslapped 
recyclable polyester staple fiber that has been needle punched and 
calendered. The recyclable polyester bale covering is formed essentially 
of non-woven fabric that is crosslapped, needlepunched, calendered, and 
cut and sewed into the fabric suitable for the recyclable bale cover.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In describing the preferred embodiments of the subject invention 
illustrated herein, specific terminology will be resorted to for the sake 
of clarity. However, the invention is not intended to be limited to the 
specific terms so selected and resulting batt is stabilized for further 
processing by needling at a specific density of about 1,200 to about 3,000 
penetrations per square inch to achieve a weight of preferably between 4 
and 14 ounces per square yard. The resulting batt is then calendered by 
pressing the batt between two rolls at a temperature of between 
300.degree. and 500.degree. F. and calendered to a thickness of between 
0.01 and about 0.100 inch. The resulting fabric is then subject to 
conventional techniques of fabric rollup. 
The fabric can be used on various types of automatic balers, i.e., Sunds, 
Lumus, etc. The fabric can also be made into sewn bags using conventional 
cut and sew techniques and equipment. Such fabric is suitable as a direct 
replacement for woven polypropylene material. 
The all polyester bale wrap, including a polyester label may be recycled 
using conventional methods to recycle polyester. The all polyester fabric 
is ground into particles which are processed through glycolysis or 
methanolysis to recycle the material. 
COMATIVE EXAMPLE 
Various samples were prepared using a blend of 90% polyester fibers and 10% 
bicomponent fibers. The bicomponent fiber commercially available as Type 
254 from Hoechst Celanese it is to be understood that each specific term 
includes all technical equivalents which operate in an equivalent manner 
to accomplish a similar purpose. 
The fiber used is a recyclable polyester fiber. These fibers should be 
between about 2 inches and 4 inches in length and have a denier or denier 
equivalent between about 2.25 and 15 dpf. The fibers are individualized, 
that is separated into individual fibers using conventional textile fiber 
carding equipment, and are then formed into a web using fibrous web 
forming devices. 
The fibers may also be treated with a fiber lubricant or finish before or 
during processing to permit subsequent needle operations to be performed. 
Such a fiber finish precludes excessive needle breakage, poor fiber 
penetration, inefficient stitching, and reduced stitching breaks. Finishes 
may include silicone lubricants, metallic soaps and low molecular weight 
polyethylene waxes to provide needle lubrication. Methods of application 
include padding, spraying or immersion and press rolling. The fibers may 
further be treated with a flame retardant. 
The fibrous web is increased in thickness by crosslapping or layering 
through the use of conventionally known multiple forming devices such as 
disclosed in U.S. Pat. No. 4,183,985. The has a polyester core in an 
isophthalic polyester sheath material. The fibers were processed into a 
fibrous web needle punched according to standard procedures and 
calendered. It was found that the fabrics calendered at 400.degree. F. 
yielded a stiffer fabric. Such fabrics are found to result in fabric tears 
as well as contamination of the fibrous materials in the bales due to the 
clinging of the bale cover material. In another case the fabrics were 
calendered at 300.degree. F. to increase elongation. In such cases tearing 
was not a problem with these fabrics. However, fiber clinging was still a 
problem. It appeared from other comparative examples that the inclusion of 
the binder fibers such as a bicomponent fiber resulted in fiber cling of 
the cover to the fibers within the bale. 
EXAMPLE 
The present invention will be illustrated with the following example. A 
blend of 65% 3 dpf by 3 inch and 35% 6 dpf and 3 inch polyester was used. 
The blend was carded, cross-lapped, and needled at 1,200 psi. 
It has been found that when all polyester fibers incorporated into the 
fabric are without a binder fiber are calendered from about 0.021 to about 
0.018 inches using the calender roll at about 475.degree. F. with the 
pressure of the calender set at 1,500 psi, a fabric was produced that 
resulted in improved tearing resistance and improved clinging resistance. 
It will be apparent to those skilled in the art, that the present invention 
may be practiced in a wider variety of embodiments without materially 
departing from the spirit and scope of this invention. It is also to be 
understood that in the foregoing specification, specific embodiments and 
components thereof, have been illustrated and discussed by way of 
illustration only and not of limitation, and that the invention may be 
practiced by those skilled in the art utilizing a wide variety of 
materials and configurations without departing from the true spirit of the 
invention.