MULTI-LAYERED PLASTIC BINDING MATERIAL

MATERIAU LIANT MULTI-COUCHES EN PLASTIQUE

English Abstract

A binding material, such as twine, formed of plastic film wrap gathered together. A
method of forming such binding material is also disclosed.

French Abstract

Matériau liant comme de la ficelle, formé d'un ensemble de films de pellicule plastique. L'invention décrit également une méthode de formage de ce matériau liant.

Claims

We claim:
1. A multi-layered binding material comprising:
a web of plastic film having a lateral dimension, and a longitudinal dimension,
wherein said web is laterally gathered such that a plurality of gathered surfaces of said web
contact, and wherein said web is longitudinally stretched to a near-yield point to cohere said
gathered surfaces.
2. A method of forming a multi-layered binding material from a web of unstretched
plastic film having a longitudinal dimension and a lateral dimension, comprising the
steps of:
(i) feeding said web from a feeding means;
(ii) laterally gathering said web such that a plurality of gathered surfaces of
said web contact; and
(iii) longitudinally stretching said gathered web to a near-yield point to
cohere said gathered surfaces.
3. A method according to claim 2 wherein said steps of gathering and stretching occur
substantially simultaneously.
4. An apparatus for forming a multi-layered binding material from a web of plastic film
having a longitudinal dimension and a lateral dimension, comprising:
feeding means for feeding said web;
gathering means located downstream of said feeding means to laterally
gathering said plastic film such that a plurality of gathered surfaces of said web contact;
stretching means for longitudinally stretching said web to a near-yield point tocohere said gathered surfaces.
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Description

CA 022117~0 1997-07-30
MULTI-LAYERED PLASTIC BINDING MATERIAL
Field of the Invention
This invention relates to binding material. In particular, this invention relates
5 to multi-layered binding material made of plastic film and method of making such binding
material.
Background of the Invention
Binding materials, such as rope and ~llappillg, are comrnonly used in the
l 0 shipping and packaging induskies. Goods are generally packed in cardboard boxes or
cartons, which are then stacked on pallets for shipping. The boxes are secured to the pallets
with straps running laterally and longitudinally. For increased pallet stability and protection
of the goods, the strapped pallets are then wrapped in shrink wrap plastic film. When the
pallet arrives at its destination and is unloaded, the film and strapping are removed and
l 5 disposed of.
The most common ~ll~phlg is a relatively expensive, flat, rigid polypropylene
ribbon. This form of strapping is typically supplied in 500' rolls. It is generally 1/s" l/2~ wide
with a ridged or uneven surface to provide grip.
To secure a load of stacked cartons to a pallet, the ~l~ping must be tightly
bound around the pallet load. Because of the sharp edges and relatively narrow width of the
ribbon, crushing or cutting of the cardboard cartons, especially those at the periphery of the
stack, often results.
Moreover, industry must pay to dispose of the scrap polyethylene film and
polypropylene ribbon generated when pallets are unloaded. However, polyethylene film is
recyclable, at a profit, if not con~rnin~ted by polypropylene.
It is known that the strength of most plastic film can be enhanced by stretchingthe film nearly to its yield point. Typically, the film reaches its yield point when it is
stretched to between l 50% and 300% of its original, unstretched length. It is also known that
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' CA 022117~0 1997-07-30
polyethylene plastic film has the property of adhering to itself. This property is enhanced
when the plastic film is stretched as surfaces of the film are brought into contact with one
another.
Summary of the Invention
It is an object of the present invention to provide a novel binding material
from polyethylene plastic film.
It is a further object of the present invention to provide a novel method for
manufacturing binding material from polyethylene plastic film.
In an embodiment of the present invention there is provided a multi-layered
binding material comprising:
a web of plastic film having a lateral dimension, and a longitudinal dimension,
wherein said web is laterally gathered such that a plurality of gathered surfaces of said web
contact, and wherein said web is longitudinally stretched to a near-yield point to cohere said
gathered surfaces.
In a further embodiment of the present invention there is provided a method of
forming a multi-layered binding material from a web of unstretched plastic film having a
longitudinal dimension and a lateral dimension, comprising the steps of:
(i) feeding said web from a feeding means;
(ii) laterally gathering said web such that a plurality of gathered surfaces of
said web contact creating multiple layers of film; and
(iii) longitudinally stretching said gathered web to a near-yield point to
cohere said gathered surfaces.
In one aspect of this embodiment there the steps of gathering and stretching
occur substantially simultaneously.

CA 022117~0 1997-07-30
In a further embodiment of the present invention there is provided an
apparatus for forming a multi-layered binding material from a web of plastic film having a
longitudinal dimension and a lateral dimension, comprising:
feeding means for feeding said web;
gathering means located downstream of said feeding means to laterally
gathering said plastic film such that a plurality of gathered surfaces of said web contact;
stretching means for longitudinally stretching said web to a near-yield point tocohere said gathered surfaces.
Brief Description of the Dr,~wil~gs
The present invention may be better understood by reference to the following
detailed description and attached drawings, in which:
Figure 1 is a perspective view of an apparatus for forming multi-layered
binding material from a web of plastic film, in accordance with an embodiment of the present
1 5 invention;
Figure 2 is a side view of an embodiment of a gatherer of the apparatus of
Figure 1;
Figure 3 is a radial cross-section of a gathered web, in accordance with an
embodiment of the present invention;
Figure 4 is an axial cross-section of multi-layered binding material, in
accordance with an embodiment of the present invention; and
Figure 5 is a radial cross-section of the binding material of Figure 4
Detailed Description
Figure 1 illustrates an embodiment of an apparatus, generally designated as 10,
of the present invention. A roll 12 of unstretched plastic film, having a core 14 is mounted
on a feed spindle 16. The plastic film can be linear low density polyethylene or any other
suitable plastic film. The plastic film is in the form of a web 18 which may be unrolled from
roll 12. Web 18 can have any width, but plastic film is commonly supplied as a 20" wide
web.

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Web 18 is fed from roll 12 to a roller 20. Feed spindle 16 and roller 20 are
shown in a vertical orientation, but it will be apparent to anyone skilled in the art that they
could be horizontal. Alternatively, the roll 12 can be supported by a pair of horizontal idler
rollers (not shown) upon which it can rotate to feed web 18 to a roller, as is well know in the
art. Feed spindle 16 will normally be motor controlled to feed web 18 at a predetermined
rate, as is known in the art.
Web 18 is fed from roller 20 to a gatherer 22. Gatherer 22 has an aperture 24
which is generally ovoid, as shown in Figures 2.
As illustrated in Figure 4, web 18 is laterally compressed and gathered into a
number of longitudinal folds 26 when threaded through aperture 24. The self-cohesive
properties of the plastic film cause abutting surfaces 28 of longitudinal folds 26 to cohere and
form a gathered web 30, downstream of gatherer 22.
Gathered web 30 is fed from gatherer 22 to guide rollers 32, 34 and thence to a
web stretching mechanism (not shown). Typically the stretching mechanism will comprise a
series of rollers having different diameters and/or rotational velocities. When gathered web
30 is fed through the stretching mech~ni~m, it is longitudinally stretched to its near-yield
point, typically 150% - 300% of its original length depending on the properties of the plastic
film. Equally, gatherer 22 may be integrated within the stretching mech~ni~m, if desired.
Stretching the gathered web has a number of consequences. First, as is well
known, the strength of the plastic film is greatly enhanced. Secondly, stretching the film
causes surfaces 28 to cohere more firmly, and flattens the gathered web 30 against the
stretching rollers. As a result, after stretching, the gathered web 30 is transformed into a
ribbon-like binding material 36, as shown in Figures 4 and 5, having superior strength
characteristics and a width determined by the width of the original web 18 and the
dimensions of aperture 24. Typically, the binding material of the present invention will have
a width of approximately 2", thus redistributing forces across carton secured with the binding
material and consequently reducing damage to the cartons. Moreover, the resulting binding

CA 022117~0 1997-07-30
material is lightweight, inexpensive to produce, and fully recyclable along with the film wrap
used to wrap pallet loads.
lt will be apparent to those skilled in the art that the foregoing is by way of
5 example only. Modifications, variations and alterations may be made to the described
embodiments without departing from the scope of the invention which is defined solely in the
clalms.

Representative Drawing