Note: Descriptions are shown in the official language in which they were submitted.
- 2190323
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PLASTIC (, U l l ING EDGE Wll~I ~ U l l ING RIBS
BACKGROUND OF THE INVENTION
FieldoftheInvention
This invention relates generally to plastic cutting edges. More particularly,
this invention relates to plastic cutting edges having cutting ribs and which are useful
in conjunction with film dispensing containers, such as tape dispensers and cartons
for ~lnmimlm foil or waxed paper.
Description of the Related Art
Cutting edges are commonly used in conjunction with film dispensing
containers to sever the dispensed film into useable lengths. The container may be a
carton cont~ining a roll of film such as a roll of waxed paper, plastic food wrap or
aluminum foil. The carton is typically provided with a serrated metal cutting edge for
tearing offusable lengths of film. The container may also be a tape dispenser such as
those used with transparent mending tapes found in homes and offlces. These
dispensers oflen include either a metal cutting edge that is separately attached to the
dispenser or an integrally molded plastic cutting edge.
There is always a risk with these containers that someone using it may get cut
by the sharp edge. Consequently, many food wrap containers include a warning to
help prevent such an injury. Thus, a cutting edge that will reduce the likelihood of
injury would be highly desired.
Some cutting edges can become dull with repeated use, thereby making it
more difficult to easily sever film that is at the end of the roll. Sharpening the cutting
edge is often impractical or even impossible if the cutting edge is perrn~nentlyattached to the container. Thus, a cutting edge that can be easily replaced or that has
a renewable cutting surface would be highly desired.
Increased concerns for the environment favor fully recyclable and/or
repulpable pacl~ging However, metal blades can not be recycled with cardboard
cartons or plastic containers.
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.
Thus, there is a continuing need for an improved cutting edge that can be
used with cartons that contain rolls of dispensable film, tape dispensers, and the like.
The utility of the cutting edge will be enhanced if it possesses certain attributes. For
example, it should have a low profile to reduce the risk of injury by being cut. It
5 should be useful with a wide variety of paper, plastic and metal films. It should be
capable of being replaced after it has been attached to a con~ainel, or removed, given
a renewed cutting surface, and reattached to the container. It should be recyclable.
Finally, the cutting edge should be easy to m~n--f~cture.
~IJMMARY OF THE INVENTION
This invention relates to plastic cutting edges having cutting ribs and which
are useful in conjunction with film dispensing containers, such as tape dispensers and
cartons for ~lllminllm foil or waxed paper. In one embodiment, the plastic cutting
edges of the invention comprise a plastic web having first and second opposed major
15 surfaces, and a plurality of separate, spaced apart, elongate plastic cutting ribs that
are formed on at least one of (and optionally both of) the major surfaces of the web.
Preferably, the ribs are substantially parallel to each other. The ribs are distributed
(i.e., aligned) longitudinally on the web and extend across the web (i.e., transverse to
the longitlldin~l direction of the web). The web also includes a longitudinally
20 extending upper edge. The ribs can terminate ~dj~c~nt to the longitll~in~lly çYtçnding
upper edge of the web so as to form the cutting surface. Alternatively, the ribs may
comprise a root portion attached to the web and a beveled cutting tip (preferably at
about 45~) that projects above the longitlltlin~lly exten~ing upper edge of the web.
The cutting edge may further include a layer of adhesive (preferably a
25 pressure sensitive adhesive) on one of the major surfaces of the web for ~tt~ching the
cutting edge to a substrate. Other techniques for ~tt~t ing the cutting edge to a
substrate include mechanical fasteners and ultrasonic welding.
The cutting edge may be attached to a container that retains a roll of a
dispensable film such that sections of the dispensable film can be cut from the roll.
30 The cutting edges of the invention are particularly useful in conjunction with food
wrap such as ~luminnm foil, waxed paper and clear plastic. Thus, in another
embodiment, the invention relates to an elongated food wrap container that
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comprises an elongated carton having an open interior. An elongated roll of
dispensable food wrap is retained within the interior of the carton, and a plastic
cutting edge according to the invention is attached to the elongated carton for cutting
sections of the dispensable food wrap from the roll. A pr~f~-led location for
attac.hing the cutting edge is the inside surface of the front wall of the carton and
adjacent to the upper edge of the front wall.
The cutting edges of the invention are also useful in conjunction with tape
dispensers. Thus, in a further embodiment, the invention comprises a tape dispenser
that includes a tape dispenser housing, a roll of dispensable tape mounted to the tape
dispenser housing, and a plastic cutting edge according to the invention for cutting
the tape. The plastic cutting edge is attached to the tape dispenser housing.
The low profile, relatively flexible ribs provide a cutting surface that may
reduce the likelihood of injury from use. By approp-iate selection of an adhesive
(e.g., by using a removable adhesive), the cutting edge may be removed and replaced
with a new cutting edge, or the cutting edge can be given a renewed cutting surface
and reattached. Because the cutting edge is formed of plastic, it may be readilyrecycled.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully appreciated with reference to the following
non-limiting drawings in which similar reference numerals designate like or analogous
components and in which:
FIG. 1 is a fragmentary pe. ~e.;li~e view of a plastic cutting edge according
to the invention and which has been folded at an angle to show the invention more
clearly;
FIG. 2 is an enlarged sectional view taken along lines 2--2 in FIG. 1;
FIG. 3 is an enlarged séctional view taken along lines 3--3 in FIG. l;
FIG. 4 is a fragmentary top plan view of a different embodiment of a cutting
edge according to the invention;
FIG. 5 is an enlarged sectional view similar to FIG. 3 and showing a further
embodiment of the invention;
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PIG. 6 is an enlarged sectional view similar to FIG. 2 and showing an
alternative embodiment of a cutting edge according to the invention;
FIG. 7 is a perspective view of a container for use with a plastic cutting edge
ofthe invention and co..~Ai~ g a film roll, a portion ofthe film roll having been
5 broken away to show the cutting edge more clearly;
FIG. 8 is a sectional view taken along lines 8--8 in FIG. 7;
FIG. 9 is an enlarged view of the area design~ted by the reference letter A in
FIG. 8;
FIG. 10 is a sectional view similar to FIG. 8 but showing the cutting edge
10 attached to the container'in a dirrelelll position; and
FIG. 11 is a perspective view of a tape dispenser for use in conjunction with a
plastic cutting edge of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, a particularly preferred embodiment of a plastic
cutting edge 10 according to the invention is illustrated in FIGS. 1 to 3. Cutting edge
10 comprises a web, backing or substrate 12 having a plurality of separate, spaced
apart cutting ribs 14 formed on at least one ofthe web's first and second opposed
major surfaces (i.e., surfaces 12a and 12b). Ribs 14 are distributed longitu~in~lly on
the web (i.e., they are aligned along the length ofthe web). Cutting edge 10 may also
include an optional adhesive layer 16. As explained below, cutting edge 10 is useful
for cutting dispensable films (especially consumer food wrap and adhesive tapes) into
useable lengths.
The length of cutting edge 10 and web 12 depends on the application, the
2~ cutting edge and the web having a length that is generally equal to or somewhat
greater than the width ofthe film that is to be cut. Cutting edge 10 is typically
elongated; that is, it has a length greater than its width. However, the length and the
width of the cutting edge may be equal. For food wrap applications, cutting edge 10
usually has a length of about 12 inches and a width of about 0.25 to 0.75 inch. For
adhesive tape applications, cutting edge 10 usually has a length of about 0.125 to 6
inches and a width of about 0.25 to 1 inch.
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Web 12 may be formed from a wide variety of polymeric materials, especially
those which are extrudable, thermally stable thermoplastics such as, for example,
polyesters (e.g., polyethylene terephtl~ te and copolymers based on polyethyleneterephth~l~te), polyolefins (e.g., polyethylene and polypropylene), polystyrene,polycarbonate, nylon, acrylics, acrylonitrile-butadiene-styrene, cellulose esters,
copolymers that comprise alte~ g units of ethylene and tetrafluoroethylene, and
blends and copolymers ofthe foregoing materials. Preferably, web 12 (as well as
cutting edge 10) is sufficiently flexible that it can wound into a roll. Typically, the
web has a thickness of about 0.003 to 0.02 inch.
In plerelled embodiments, ribs 14 comprise a root or proxhl,al end 18
attached to web 12, and a distal end or cutting tip 20 that projects above ~dj~cent
longitudinally eYt~n~ing upper edge 22 of web 12. Ribs 14 are typically elongatestructures that extend across web 12; that is, the ribs are transverse to the
longitll~in~l axis of web 12. Ribs 14 usually form an angle of about 90~ with the
longitudinal axis of web 12, but may be oriented at a different angle, for example
about 45~ as shown in FIG.4.
Ribs 14 may be formed from any polymeric material, preferably one which is
an extrudable, thermally stable thermoplastic. Materials useful for forming web 12
may also be used to provide ribs 14. Preferably, the web and the ribs are formed of
the same material, although this is not required. In addition, the polymeric material
for web 12 and/or ribs 14 may be supplemented with various additives such as
stabilizers, antioxidants, thixotropic agents, nucleating agents, flow control agents,
colorants (e.g., titanium dioxide, carbon black), and fillers (e.g., calcium carbonate,
abrasive grains, etc.).
As explained more fully hereinbelow, cutting edge 10 is readily formed by an
extrusion process. Accordingly, the thickness, the di~meter, and the cross-sectional
shape and dimensions of ribs -I4 are determined by the shape of the die orifice
opening, the relative die angle, the position or location of the orifice openings, the
extruder flow rate (mass of extrudate as a function of time), the rate of draw on the
extrudate, the rate of quenching of the extruded material as it leaves the die orifice,
the stretch ratio if the extrudate is oriented, and the calendaring pressure if the
~1~0323
extrudate is calendared. These parameters are all well known to those of ordil-~y
skill in the extrusion art.
Before any optional orientation of the extrudate, the ribs typically have a
subst~nti~lly circular cross-sectional shape or an omega (Q) shaped cross-section,
5 depending upon the configuration of the die orifice openings. However, the cross-
sectional shape of the ribs is not so limited and other cross-sectional shapes are
possible incl~lding squares, rectangles, triangles and bell shapes. If the extrudate is
oriented (i.e., stretched) in the m~çhine direction or calendared, the cross-sectional
shape of the ribs often becomes distorted. For example, they may flatten or elongate.
The contact angles made by the ribs with respect to the major surface ofthe
web to which they are att~ched (e.g., upper or first surface 12a in FIG. 1) may range
from about 10~ to 160~, more preferably from about 10~ to 140~. At angles less than
about 10~, it can become more difficult to m~mlf~ctllre the cutting edge with
conventional extrusion equipment and co,."~,elcially feasible operating speeds. The
15 mass of ribs projecting above the rib-bearing surface of the web must be sufficient to
provide an effective contact with the film that is to be cut by the cutting edge. That
is, the effectiveness of the cutting edge may be reduced if an insufficient mass of ribs
projects from the web.
Also as noted below, the ribs may be coextruded with the web (i.e., extruded
20 at the same time) or extruded separately on to a hot or cold pre-formed web.
Preferably, the ribs tend to fuse to the web and, upon doing so, a portion of the ribs
flows into the spaces between each rib, thereby distorting the original cross-sectional
shape (i.e., the shape immediately upon emerging from the extrusion die). Withinthese guidelines, at least 30%, more preferably at least 80%, ofthe original cross-
25 sectional mass of the ribs project from the rib-bearing surface of the web.
Ribs 14 are spaced apart so as to provide an alternating series of ribs 14 and
lands or flat portions 24 on upper web surface 12a (the surface of web 12 from which
ribs 14 project). Typically, each rib is substantially identical to each other rib, and the
rib-to-rib spacing is also substantially equal. The ribs are also subst~nti~lly parallel to
30 each other. By "substantially identical, " "substantially equal," and "substantially
parallel" it will be understood that minor di~erences in individual die orifice openings
as well as orientation and calendaring of the extrudate can slightly alter the cross-
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213U~23
sectional shape of any individual rib, its spacing from adjac~nt ribs, and its parallelism
to adjacçnt ribs. Within these guidelines, and with rerelence to FIG. 2, the thickness
"T" of ribs 14 is typically about 0.17 to 0.40 mm, the width "W" ofthe ribs is
typically about 0.23 to 0.50 mrn, and the rib-to-rib spacing "S" is usually about 0.50
toO.75mm.
The number of ribs per linear inch distributed longit~ldin~lly on web 12 will beinfluenced by the nature ofthe dispensable film that is to be cut by cutting edge 10
and the fineness ofthe cut that is desired. It is plerelled that there be about 10 to 30
ribs per linear inch of web, most preferably about 25 ribs per linear inch so as to
provide a nominal rib center-to-rib center spacing "C" of about 1 mm.
As mentioned above, each rib 14 preferably includes a distal end or cutting tip
20 that first contacts the film to be severed and initiates cutting of the film. The
distance that cutting tips 20 is selected to project above adjacent longitu(lin~lly
exten.1ing upper edge 22 of web 12 will be infl~1enced by the stiffness of the cutting
tip and the nature of the dispensable film that is to be cut. As best shown in FIG. 3,
the height "H" of the cutting tip is typically about 0.14 to 0.25 mm in the mostprefellt;d embodiments. The height ofthe cutting tip is influenced by the angle "a"
of the cutting tip which, as best shown in FIG. 3, is preferably less than 90~, more
preferably about 30~ to 60~, and most preferably about 45~. However, as shown inFIG. 5, the cutting tip may form a 90~ angle, in which event rib 14 does not include a
separate cutting tip that projects above adjacPnt longitudin~lly exten~ing upper edge
22 of web 12. In FIG. 5, ribs 14 terminate a~jacçnt to longihldin~lly e~tçn~ing upper
edge 22 of the web. The cutting edge of FIG. 5 is useful with a film of limited
extensibility such as all-minl-m foil.
Another embodiment of a cutting edge according to the invention is shown in
FIG. 6. Cutting edge 30 comprises a web, backing or substrate 32 which may be
formed of the same materials that can be used to provide web 12, a plurality of
separated, spaced apart ribs 34 distributed longitudinally on the web and which are
similar to ribs 14. Cutting edge 30 may also include an optional adhesive layer 36.
The embodiment of FIG. 6 is similar to that shown in FIGS. 1 to 3 except that ribs 34
project from both major surfaces of web 32 (i.e., upper and lower surfaces 32a and
32b, respectively), rather than from only one major surface.
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Cutting edges according to the invention are particularly useful for cutting a
film into useable lengths. 'Yilm" refers to materials that are subst~nti~lly longer and
wider than they are thick and is used broadly to include paper films, non-woven films,
plastic films and metals films. The films may be partially or completely coated on one
S or both surfaces so as to provide, for example, treated films, adhesive tapes,
repositionable easel pad sheets and the like. Other uses include the cutting of pallet-
wl~ph~g films, facsimile tr~n~mi~.sion paper dispensed from a roll, and other sheet
and roll goods.
One particularly plere,led use for the cutting edges of the invention is shown
in FIGS. 7 to 9 where the cutting edge is used in conjunction with a container or
carton 40 that contains a film roll 42. Film roll 42 may be a roll of waxed paper,
clear plastic food wrap, all1rnin-lm foil, and the like. Carton 40 jS typically formed
from a cardboard carton blank that is folded and glued into the desired shape. More
specifically, carton 40 ;S elongated and comprises an elongated bottom wall 44 to
which are connected an elongated front wall 46, side walls 48 and 50, and an
elongated rear wall 52 that are joined together to form carton 40 having an openinterior portion in which film roll 42 is received. Film roll 42 is typically wound
about a cardboard core 54.
Carton 40 conventionally further includes a cover 56 that comprises a top
wall 58 and a closure flap 60 at the forward edge of the top wall. Cover 56 ;S
movable between an open position (as shown in FIGS. 7 and 8) and a closed position
(not shown separately in the dl ~wings) so as to enclose film roll 42 within carton 40,
closure flap 60 being adjacent to the upper portion of front wall 46 in the closed
position. Cover 56 is adapted for such movement by being hinged to the upper edge
of rear wall 52J the hinge connection being shown at 62. Hinge connection 62 maybe a continuous piano hinge, one or more individual mechanical hinges, or, most
commonly, a crease or line of weakness formed in the cardboard carton.
A cutting edge according to the invention (which is illustrated in FIGS. 7 to 9
as cutting edge 10) is secured to any surface of carton 40 that permits a user to
dispense film 42 and cut it into usable lengths by drawing the film against cutting ribs
14. Cutting edge 10 may be secured to carton 40 by any convenient att~chment
means such as ultrasonic welding, mechanical fasteners (e.g., staples, clips, pins,
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rivets), or adhesives. Adhesives are particularly prerelled and any of a wide variety
may be used to secure the cutting edge to the carton. Tncluded among these are hot
melt adhesives, solvent-coated adhesives, heat-activated adhesives, and solvent-activated adhesives. Pressure sensitive adhesives are most useful because they permit
5 quick and easy ~tt~chmçnt of the cutting edge to the carton. Represelllali~e
examples of useful pressure sensitive adhesives include acrylate adhesives, tackified
natural rubber adhesives, tackified block copolymer adhesives, poly alpha-olefin adhesives, silicone adhesives, and the like. The adhesive may be provided as a double
sided adhesive tape. Removable adhesives may be useful in providing a cutting edge
10 that can be replaced or renewed.
FIGS. 7 to 9 show cutting edge 10 secured to an upper edge 64 of inside
surface 66 of front wall 46 such that cutting tips 20 project above longitu~in~lly
f~Ytenrling front wall upper edge 64 for easy çn~gement with film 42 as it is being
dispensed. (The size of cutting tips 20 and their projection above edge 64 are
15 exaggerated in FIGS. 8 and 9 to show the invention more clearly.) As shown in FIG.
10, the cutting edge may be attached to other surfaces of carton 40. For example, it
may be secured to the outer surface ofthe edge of bottom wall 44 that is ~ cent to
front wall 46 such that cutting tips 20 project forward of the front wall. Although
not shown separately in the drawings, the cutting edge may also be secured to inside
20 surface 68 of closure flap 60 and adjacent to the free end thereof such that cutting
tips 20 extend beyond the longitudinally exten~ing free edge of the closure flap.
In another embodiment, as best shown in FIG. 11, a cutting edge according to
the invention may be used in conjunction with a tape dispenser 70. Tape dispenser
70 comprises a housing 72 (typically forrned of plastic) and a dispensable tape roll 74
25 rotatably mounted to the housing by a hub 76. A cutting edge (illustrated in FIG. 11
as cutting edge 10) is secured to curved front wall 78 of the housing by a mechanical,
adhesive or other fastener or by providing a slot in the housing in which the cutting
edge is received. The cutting edge may be removably attached to the tape dispenser
housing. In any event, the cutting tips project above tape landing zone 80 such that
30 when tape 74 is temporarily secured to the landing zone, a useable length thereof can
be readily cut from the roll by drawing the tape against the cutting edge. Tape roll 74
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may be Ir~n~palellt mending tape, m~king tape, autoclave tape, correction/cover up
tape, and the like.
Cutting edges according to the invention may be readily prepared by
coextrusion techniques. For example, the cutting edge may be produced using a dual
S manifold die to which is coMected a pair of separate extruders. The dual manifold
die can include a slot orifice in the lower manifold for providing web 12 and a series
of closely spaced orifices in the upper manifold for providing ribs 14. Raw materials,
usually in the form of pellets, are melted by the extruders and delivered as twoseparate molten raw material streams to the dual manifold extrusion die. As the
extrudates leave the dual'manifold die in the molten state, they can be immediately
combined to form a rib-bearing film. The output ratio of the web-forming extruder
to the rib-forming extruder is typically in the range of about 1:1 to 8:1, based on the
weight of the materials.
Alternatively, the extruders may provide their molten raw materials streams to
a single combining manifold die, the molten raw material streams being joined and
extruded through a single die orifice that comprises a plurality of notches for forming
the ribs and an elongated slot for ro~ ing the web. In any event, once the rib-bearing
film leaves the die (whether dual manifold or single combining manifold type), it is
typically drawn onto a chilled casting roll, good contact with the casting roll being
facilitated through the use of an air knife or electrostatic pinning. The rib-bearing
film can be drawn through a nip formed by the chilled casting roll and a second
casting roll that is run in the opposite direction.
The rib-bearing film, whether produced with a dual manifold die or single
combining manifold die, may be oriented in the machine direction with a stretch ratio
of up to 10:1. The rib-bearing film may also be calendared by passing the film
through one or more nips between metal rolls to reduce the caliper of the film.
Calendaring can have the effect of ch~nging the rib shape, for example, from a
circular shape to an elliptical or trapezoidal shape and can also help to reduce the
stiffness of the film, thereby rendering it more pliable.
An optional adhesive layer (so as to provide adhesive layer 16 or 36) may be
applied to the rib-bearing film using techniques similar to those used to m~nllf~ct~lre
adhesive tape. The rib-bearing film can be treated (e.g., corona-treated, primed, etc.)
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so as to improve the adhesion of the adhesive to the film. Also, if desired, theadhesive layer may be protected from dirt and other co~ by l~...in~ a
release liner (e.g., a silicone or wax-treated paper or plastic film) thereto.
Alternatively, the rib-bearing surface of the film can be treated with a low adhesion
5 backsize to permit the film to be wound into a roll. Techniques for m~mlf~ctllring
adhesive-coated, rib-bearing plastic films are described in more detail in U. S. Patent
No. 5,173,141 (~,esem~n et al.).
At this point in the m~nllf~ct~lring process, it will be understood that the rib-
bearing film comprises an ess~nti~lly continuous web, sheet or men,~ e, and a
10 plurality of separate, spaced apart, elongate ribs that extend in the machine or
extrusion direction (i.e., parallel to the length ofthe ess~nti~lly continuous film).
Cutting edges according to the invention (usually in the form of narrow strips) are
obtained from this rib-bearing film by slitting or cutting the same in the cross-film
direction (typically perpendicular to the length of the film). In the res -lting narrow
15 strips, the elongate ribs are distributed longitudinally on the web (i.e., they are aligned
along the length of the narrow strip web), but extend across the web (i.e., transverse
to the longitudinal axis of the narrow strip web). Cutting tips 20 are formed by bevel
cutting the rib-bearing film at the desired angle. Alternatively, the rib-bearing film
can also be square cut (i.e., in a plane perpendicular to the plane ofthe film) so as to
20 provide the embodiment shown in FIG. 5. The cutting edge may then be applied to a
container such as carton 40 by l~min~ting a cutting edge that inchldes an adhesive
layer to the desired surface of the carton. Alternatively, a cutting edge that does not
include an adhesive can be mechanically ~tt~ched or ultrasonically welded.
A variety of continuous, integrated m~nuf~ctllring approaches are also
25 possible. For example, an incoming, essenti~lly continuous rib-bearing film can be
laminated to a carton blank (i.e., a flat piece of cardboard that has been cut for the
carton but which has not yet béen folded into shape) and then bevel cut in the cross-
film direction so as to provide a cutting edge having beveled or angled cutting tips.
The invention will be more fully appreciated with reference to the following
30 non-limiting examples.
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i
Examples 1 to 9
A series of plastic cutting edges with cutting ribs according to the invention
was plepared by a coextrusion process using a dual manifold die. Both the ribs and
the web were formed from virgin polypropylene resin (from FINA, Cosden Chemical
Division).
More specifically, resin for the web was supplied by a 3.5 inch ~i~meter
extruder operating at 500~ F and 47.5 revolutions per minute (RPM), while resin for
the ribs was supplied by a 2 inch (li~met~r extruder operating at 525~ F and a rate
specified in Table 1 below. The molten polypropylene resin streams from the two
extruders were supplied to a dual manifold die. The upper die was 32 inches wideand in~hlded 25 rib-forming circular orifices per linear inch, the orifices being spaced
0.040 inch on center and having a di~meter of about 0.013 inch. The lower, web-
forming orifice, was a 35 inch wide, 0.025 inch high slot.
The ribs and web were combined upon exiting from the dual manifold die and
were drawn from the die with the aid of a casting wheel n~ ed at a temperature
of 110~ F. The speed of the casting wheel is specified in Table 1 below. Several of
the examples were oriented in the m~hine direction, as noted in Table 1 below,
where the reported ratio is the orientation in the m~chine direction (MD) to theorientation in the cross-film direction (CD).
Examples 7 to 9 were calendared by passing the rib-bearing film between a
pair of nip rollers. The thickness of the resulting film (web and ribs) was 0.0083 inch
for example 7, 0.0071 inch for example 8, and 0.0066 inch for example 9.
The web surface not bearing ribs was corona-treated to at least 38 dynes/cm
and was then coated with a tackified thermoplastic elastomer block copolymer hotmelt pressure sensitive adhesive. A silicone release material-coated paper release
liner was then l~min~ted to the adhesive layer to protect the same.
The rib-bearing film was then trimmed to a 12 inch width and bevel cut with a
matte cutter from the rib-bearing side of the film first so as to provide 45~ cutting
tips.
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Table 1
Example Rib-Forming CastingWheel Orientation
Extruder Rate Speed (~:CD)
(RPM) (feet/minute)
15.0 1.05: 1
2 . 65 27.5 1.05: 1
3 130 27.5 1.05:1
4 130 21.5 1.05: 1
130 15.0 5:1
6 150 15.0 5:1
7 100 15.0 5:1
8 100 15.0 5:1
9 . 100 15.0 5:1
The ability of the cutting edges from examples 1 to 9 to cut waxed paper was
tested. More specifically, an arrangement similar to that shown in FIGS. 7 and 8 was
~im~ ted by adhesively bonding a 12 inch long sample ofthe cutting edge to a piece
of plain, flat cardboard. A piece of corrugated cardboard was then bonded to thesurface of the flat cardboard carrying the cutting edge using double sided adhesive
tape. The corrugated cardboard was positioned beneath the cutting edge and in
abutment therewith. This assembly was then attached to the vertical edge of a table
such that the flat top surface of the table ~imulated bottom wall 44 in FIGS. 7 and 8.
WAXTEX brand waxed paper (from Menominee Paper Co., Menominee, MI) which
unrolled from the bottom, was drawn against the cutting edge.
This arrangement was also used to test examples 1 to 3, 5, and 7 to 9 for their
ability to cut alllminum foil (W41 brand from Pack~ging Corporation of America
Northbrook, IL). The ability of the cutting edges from examples 4 and 6 to cut
mimlm foil was evaluated by taking a box ofthe same brand of ~lllmimlm foil,
removing the serrated metal cutting strip provided by the m~n~lf~Jrer, and replacing
the same with a plastic cutting edge according to the invention. The resulting
construction was the same as that shown in FIGS. 7 and 8.
Each of the nine examples was able to cut both waxed paper and aluminum
foil.
The ability of an embodiment similar to that shown in FIG. 5 to cut waxed
paper and aluminl~m foil was then evaluated. The rib-bearing films from examples 1
'- ~1903~3
to 9 were trimmed to a 12 inch width and square cut from the rib-bearing side of the
film to form a 90~ angle as shown in FIG. S. The resulting cutting edges were
attached to boxes of waxed paper and ~luminl1m foil (same brands as previously
used) to provide a construction like that shown in FIGS. 7 and 8. Each of the nine
5 examples was able to cut both waxed paper and ~lllminllm foil, although the
pe~ ..ance with ~lllmimlm foil was better.
Example 10
A plastic cutting edge according to the invention was prepared by taking the
rib-bearing film from example 6 and diagonally square cutting the same. The
10 resulting cutting edge had ribs oriented at a 45~ angle with respect to the longitutlin~l
axis of the web (as shown in FIG. 4), and the ribs termin~ted ~dj~cent to the
longitudinally ext~n(lin~ upper edge of the web (as shown in FIG. 5, a=90~). Thecutting edge was attached to a box of W41 brand ~luminum foil, so as to have theconfiguration shown in FIG. 10. The cutting edge of example 10 was able to cut
15 aluminum foil.
Examples 11 to 13
A series of three plastic cutting edges according to the invention was
prepared using extrusion grade polycarbonate (from General Electric Cor..pa..y,
Schenectady, NY) and a copolymer based on polyethylene terephthlate (EASTAR
20 PETG copolyester 6763 from F.~mAn Chemical Company, Kingsport, TN) for the
web and/or the ribs as specified below in Table 2 where "PC" is polycarbonate.
A 1.75 inch diameter extruder operating at 25 RPM was used to provide a
molten raw material stream for the web. The web extruder was m~int~ined at 480~ F
for examples 11 and 13 and at 550~ F for example 12. A 1.25 inch diameter extruder
25 operating at 37 RPM was used to provide a molten raw material stream for the ribs.
The rib extruder was n,Aillt~ined at 550~ F for examples 11 and 12 and at 480~ F for
example 13.
The two molten raw material steams were supplied to a dual manifold die.
The upper die was 12 inches wide and included 14 rib-forming circular orifices per
30 linear inch, the orifices being spaced 0.060 inch on center and having a diameter of
about 0.020 inch. The lower, web-forming orifice, was a 12 inch wide, 0.020 inchhigh slot.
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The ribs and web were combined upon exiting from the dual manifold die and
were drawn from the die with the aid of a casting wheel running at 8 feet/minute and
ed at a temperature of 70~ F. The examples were neither oriented nor
calendared. The rib-bearing films were then diagonally bevel cut to have the
5 configuration shown in FIG. 4 (ribs oriented at 45~ with respect to the longitudinal
axis of the web and with a 45~ beveled cutting tip).
Using SCOTCH brand acrylic adhesive transfer tape #924-100 (from 3M
Company, St. Paul, MN), the cutting edges were applied to difIerenl boxes of food
wrap (W41 brand ~ mimlm foil, WAXTEX brand waxed paper, and GLAD WRAP
10 plastic wrap from First Brands Corporation, Danbury, CT) so as to have the
configuration shown in FIG. 10. Example 12 cut the waxed paper and the alumin-lmfoil. Examples 11 and 13 cut all three food wraps.
Table 2
Example Web Ribs
11 PETG PC
12 PC PC
13 PETG PETG
15The cutting edges of the invention offer many unique advantages. The low
profile, relatively flexible (as co",paled to metal), cutting ribs provide a cutting
surface that may reduce the likelihood of injury from use. By applopliate selection of
a l~min~ting adhesive (e.g., by using a removable adhesive), the cutting edge may be
removed from an article to which it has been applied and replaced with a new cutting
20 edge. Thus, a cutting edge that has become dull with use can be replaced.
Alternatively, the cutting edge could be removed from the co-~ainer and renewed by
cutting the edge in the longitlldin~l direction with, for example, a conventional, single
arm table top paper cutter. Because the cutting edge is formed of plastic, it may be
readily recycled.
25Various modifications and alterations of this invention will become appal enl
to those skilled in the art without departing from the scope and spirit of this
invention, which is defined by the accompanying claims. It should be understood that
this invention is not to be limited to the illustrative embodiments set forth herein.
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