Note: Descriptions are shown in the official language in which they were submitted.
10855
Field of the Invention
The invention relates to an improved method and
apparatus for embossing the leading edge segment of a
roll of consumer type, wrapping cling film and to the
roll of film so produced.
Background o the Invention
Thermoplastic self-supporting thin film of the
kind which clings strongly to itself and other surfaces
has been rolled in various lengths and sold in dispensing
cartons to the public mainly for household use. Although
this type of household product has found wide acceptance, .
one complaint has been the difficulty in locating and
separating the leading edge of the cling film to initiate
the start of the roll. Once the leading edge of the film
is separated rom the under~ying layer of film, a desired
length of film is peeled from the roll and severed using
any of the conventional cutting means employed on the
customary carton ln which the roll is packed. The leading
edge of the film remaining ater the severing and removal
of the desired length of film is usually pressed agains~
the wall of the carton so as to be ready when an addi-
tional length of film is required. Consequently, it is
the initial leading edge of a new roll of packed cling
film that is dificult to locate or find and difficult to
peel away to staxt the roll. Although film roll starting
means or convenience features have been employed with
some success to initiate the start of a roll, the diffi-
- culty in providing such means or features rom a manu~
facturing standpoint has sometimes created pro~lems for
the manuacturer.
2.
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~ 10855
One proposed solution to solve the problem
- whereby the leading edge o a cling film adhere to the
underlying layer of film is disclosed in U.S. Patent
3,945,495. Specifically, this patent discloses the .
concept whereby the leading edge of the roll is treated
or coated with a substance that unbalances the degree of
shrinkage at the opposite suraces of the edge such that
the edge will curl, preferably away from the surace of
the roll, during storage. An apparent limitation or ~
drawback in this approach is that a coating step has to
be performed on the film.prior.to it being packaged in a
consumer type dispensing carton.
Another proposed solution is to emboss the : :~
leading edge o the roll using a conven~ional heat platen
or strip to reduce the blocking or sticking of the edge
of the film to the underlying layer. This approach, as
generally discussed in U.S. Patent 3,501,363, entails the
feeding of the film between a heated steel roll, or
platen secured to a roll, having.a desired pattern etched
- ,
or cut into its surface and a firm rubber-type backup
rolI so that by using conventional actua~or means, such ;~ :~
as a hydraulic ram, one o the rolls can be urged against
the other roll thereby causing the segment of film there-
between to be heated in selected areas. This selected
heating of the film results in a corresponding shrinkage -
of small selected areas of the film thereby imparting to
the surace of the film embossed raised and depressed
areas. Embossing the film in this manner at high speeds,
however, is difficult since the film generally intended
.
.-~ 10855
~ `7
for consumer use is relatively fragile and may be suscep-
tible to breaking upon contact with the heated embossing
platen or roll. Another drawba~k is the difflculty in
maintaining the precise temperature control of the platen
or roll since if either is too hot, it may excessively
thin the film causing proneness to tear propagation and
if either is too cold, the embossing may not be distinct
enou~h to reduce blocking or sticking of the edge to the
underlying layer
In the normal production of cling film rolls in
50 feet (15.24 meters), 100 feet (30.48 meters), 125 feet
(38.10 meters) or some other preselected length, t~e film
is usually supplied rom a supply source on a continuous
basis to an embossing section o an apparatus where the
heated etched platen is actuated to impart selective
shrinkage areas to a transverse portion of the film. The
film is.then further fed to a rolling and severing station `
where it is contLnuousLy wound on a core into preselected
length rolls and severed across the embossed segment o~
the.film so that the embossed segment of the ~ilm wLll
form the leading edge of the completed roll. As soon as
one winding cycle approaches completion, the roll of film
is automatically removed and an empty core is moved into
position for receiving the leading edge of the remaining
~ilm being fed. Thus preselected lengths of rolled film
are produced on a continuous basis. An apparatus for
accomplishing this continuous operation is disclosed in . .
U.S. Patent 3,697,010 and is obtainable commercially from
the Paper Converting Machine Company, Inc. as the 81"
. 10855
Poly Rewinder Machine 4769. One drawback, howeverl is
that during the operation of the apparatus, the embossed
segment of the film sometimes is advanced or delayed out
of proper coordination with the severing means resulting
in the severing of the film at a location other than at
the embossed segments. When this occurs, the apparatus
is stopped and the timing for actuating the heat embossing
platen has to be adjusted which usually takes about 20 ~ :
minutes, In addition to this, the platens are expensive
to resurface and more expensive ~o replace.
An object of the present invention is to pro~
vide.an apparatus for continuously windlng film into pre- .~
selected length rolls with an embossing drum ha~ing on a ~ .
- transverse portion of its surface a removable projected
nodulose segment whi~h cooperates with an in-line support
surface for imparting to selected transverse segments of .:.
a film strip being fed therebetween a substantially
:
nodulose contour. . . .
. Another object of this invention is to provide
a method for imparting a nodulose contour to selected
transverse areas of a continuously fed film prior to the
film being wound into rolls of various lengths.
Another obiect of this invention is to provide .:
embossing means for use with film winding machines that ::
is relatively inexpensive to make and requires a minimum
of time to adjust. : . -
Another object of this invention is to provide
on a continuous and consistent basis rolls of cling film
each having a leading edge that is readily identifiable
and adapted for easy grasping to initiate the start of
the roll.
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10855
Summary of the Invention
The invention relates to a roll of consumer type
plastic wrapping cling film having a relatively high ten-
dency to cling to itself, the improvement comprising the
leading edge portion,of the film having a plurality of ~ -
. surface disturbances consisting of small stretched areas
projecting rom the surface thus forming a substantially
nodulose leading edge portion which is readily identi-
fiable and adapted for easy grasping to initiate the
start o the roll. The width of the leading edge portion
Gan vary between about 0.5 inch (1.27 cm) and about 3.0
inches (7.62 cm) for most applications and preferably
between about 1.0 inch ~2.54 cm) and about 2.0 inches
.(5.08 cm). The disturbances forming the nodulose leading
edge portion of the film should be within the dimensional
limits specified belo~ for "nodulose,surface".
The invention also relates to a method for
imparting a nodulose contour to selected transverse areas
of a fLlm web comprising the steps: ,
(a) aligning a rotatable drum adjacent a
yieldable support surface so .as to define a passage
through which a continuous web of fi,lm can be fed, said
rotatable drum having secured to its surface a longitu- .
dinal atrîp having a projected nodulose surface; :.
(b) feedi~g a continuous strip of film under
tension from a film supply source through said passage;
. (c3 winding the fllm discharged from the
passage into a roll;
. . ' ' ' - '
6.
~ 10855
(d) contacting the film with the rotatable
drum at preselected intervals corresponding to the
transit of preselected lengths of film so that the pro- :
jected nodulose surface of the strip compresses a corres-
ponding segment of the film against the yleldable support
surface thereby imparting to the film a nodulose surace
contour composed of a plurality of disturbances con-
sisting of small stretched area projections; -
~e) cutting the film transversely across its
nodulose surface so that the cut trailing edge of the ;
film web forms a substantial nodulose leading edge for
the rolled film; :
(f) winding the leading edge of the remaining
cut film being discharged from the passage into a new
roll; and
(g) repeating steps (d) through (f) at least
once.
~ The in~ention also relates to an apparatus for
imparting a nodulose contour to selected transverse areas
on a film web which comprises:
(a) means for continuously eeding a strip of
fllm from a supply source to means for winding the ilm
into at least one roll; . .
(b) tension means disposed proximal to and
downstream of said supply source for imparting tension to
the film;
(c) a yieldable support surface disposed down~
. stream of said tension means;
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10855
9~7
(d) a rotatable drum aligned with the support
surface so as to define a passage through which ~he film :~
can pass after leaving said tension means, said rotatable
drum having secured to its surface a longitudinal strip
having a projected nodulose surface;
(e) nipping means for periodically establishing
a nipping relationship between said rotatable drum and
said support surface and rotating mçans for rotating said ''
rotatable drum so that after a preselected length of film
is fed through said p,assage, the longitudinal projected
nodulose surface of said strip will contact and compress
the film onto the support surface, thereby imparting to a
corresponding surface of the film a nodulose contour; and
(f~ means or winding up said film in a roll
after Lt is discharged from the passage formed by the
rotatable drum and support surface.
Optionally the apparatus may be provided with
the following features~
~ ~g), cutting means for severing the film after
: 20 a preselected length is wound into a roll; and .
~h) means for synchronizing said rotating
means, said nipping means and said cut~ing means so as
' to align the nodulose surface o the film with the cutting.
means so.that the film will be severed transversely
across the nodulose surface of said film, thereby pro~
viding a wound roll of film having a nodulose leading
edge portion.
It is to be unders~ood ~hat the degree of
pressure required to compress ,the nodulose surface strip
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... . . .
108S5
~ 7
into the film which in turn is orced against the yield-
able support surface to impart a permanent surface
disturbance in the film consisting of a plurality of
projected areas or nodules will depend on the particular
material of which the film is made, the thickness of the
ilm, the time or dwell period that the film i9 com~
pressed, and the height of the projected nodules on the
surface of the strip. Once the film material and the
nodulose surface strip are selected, any artisan familiar ~ ;
with the embossing of thermoplastic films can easily
determine what pressure should be applied to the strip
for compressing the film into the yieldable support so as ~-
to permanently cause a disturbance in the surface of the
film by imparting to the surface oL the film a plurality
of small stretched-area projections. It is also to be
unders~ood that in order to reduce blocking or sticking
of the leading edge portion of a roll of film to its
underlying layer~ the plurali~y of stretched area pro- !
jections should extend substantially and ~niformly across
the edge of the film and extend approximately inward at
least about 0.5 inch ~1.27 cm?. For best results, the
projected area of the disturbances or nodules should be
within the dimensions as specifled below and should
occupy at least about 40% of the surface of the film,
i.e., a~ least 40% o~ ~he surface area forming the edge
portion of the film should be stre~ched into ~he plurality ~ ~
of projecting nodules. ~ ~ -
As used herein, a nodulose surface shall mean
a coarse, rough, gritty or pebbly surface composed of
~.. ..
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10855
similar or different projected surface disturbances
varying in projected height between about 0.005 inch
(0.127 mm) and about 0.080 inch (2.032 mm), preferably
between about 0.01 inch (0.254 mm) and about 0.02 inch
(0.508 mm~ and more preferably about 0.016 inch (0.406
mm). In addition, each surface disturbance or nodule
should have a projected area on a plane parallel to the
surace of between about 19.6 square mil5 (o. ~12 square
mm) and about 0.005 square inch (3.23 square mm).
Examples of nodulose surfaces would be emery cloth,
sandpaper, embossed foil, and the like. An important
criteria for the nodulose surface is that the projected
surface disturbances be sufficiently hard to physically
displace and stretch selected corresponding areas o the
film against the support surface so as to impart a
plurality of small stretched-area projections on the
surface of the film. If the height of the surface
disturbances exceeds 0.08 inch (2.032 mm), then using the
normal conventional cling film intended for household
purposes, the etched surface formed by such dis~urbances~
would probabl~ penetrate and pierce the film thus increas-
ing its proneness to tear or sever during the winding
operation. On the other hand, if the projected height of
the surface disturbances is less than 0.005 inch (0.0127
cm), then the nodulose sur~ace imparted to the film will
not be distinct enough to reduce ~locking or sticking of
the leading~edge of the film to the underlying layer when
the film is wound into a consumer type roll.
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10855
As used herein, the projected nodulose strip on
the drum intended for use in this invention can compriss
a strip of emery cloth, sandpaper, embossed foil, or th~
like, secured to the circumference of the drum by such
means as conventional adhesive, double-sided adhesive
tape, or the like. The width of the strip should be
between about 1.0 inch (2.54 cm)-and about 6.0 inches
~15.24 cm) for most applications and preferably should be
between about 2 inches (5.08 cm) and about 4 inches
(10.16 cm) when intended to produce rolls of film for
household use.
Cling film such as polyolefin films as dis-
closed in U.S. Patent 3,423,274 to W. J. Lahm et al are
examples of films exhibiting good cling characteristics.
However, unmodified polyolein film may possess low slip
characteristics and thus must normally have cling addi-
tives lncorporated to improve or regulate its cling
characteristics. Cling additives are well known in the
art and include such materials a6 the mono- and diglyc-
erides of fat-forming fatty acids and mixtures thereof,
as described in U.S. Patent 3,048,263 to Sacks et al.
These additives can be incorporated in various fle~ible
films ~o yield a clingable film admirably suited for use
in this invention. For example, U.S. Patent 3,501j363
discloses a transparent self-supporting polyethylene film
having cling additives of mono- and/or diglycerides of
fat-forming fatty acids which have excellent cling char-
acteristics and handleability properties. Other possible
materials for use as adherent surface films include
;~
11. ``' '
f ~ ' 10 8 5 5
polyvinvylidene chloride (PVDC), polyvinyl chloride (PVC),
rubber hydrochloride, and the like Thus~ it is well
known in the art how to fabricate flexible cling film
having a balance between effective cling properties and
good handleability.
The cling film for use in this invention can
range in thickness from about 0,25 mil (0,006 mm) to
about 1 25 mils (0.031 mm) depending on the strength
required for the particular appllcation. Preferably,
a film thickness of about 0.5 mil (0.0~7 mm) is deemed
suitable for most household applications
Brief Descrip_ion of th_ Drawin~
Figure l is a schematic side elevation view of
an apparatus employing the novel embossing elements of
this invention.
Figure 2 is an enlarged fragmentary side eleva-
tional view of the embossing station of the apparatus
of Figure 1.
Figure 3 is a perspective view of a segment of
a cling film of this invention having a nodulose surface
portion
Figure 4 i9 a sectional view taken along line
4-4 of Figure 3.
Detailed Description
In Figure 1 there is shown a schematic side
view of a film wrap web winder machine of the general
type disclosed in U.S P~tent 3,697,010. Specifically,
the machine basically comprises a film supply
12.
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10855
~ '7
station composed of a ro~atable mandrel 2 which contains
the film feed stock 4. The film web 6 is fed from the
feed stock 4 and passed through a tension station com-
posed of three rolls 8, 10 and 12, with rolls 8 and lO
being fixed idler rolls horiæontally spaced apart and
roll 12 being a variable height "dancer" roll disposed
midway between and below rolls 8 and 10. The tension of
the film web is controlled by the weight o the "dancer"
roll lZ and ~he drive speed of the mandrel 2 which is
driven by conventional motor drive means (not shown~.
The film web is discharged from the tension
station and fed into an embossing station comprising a
yieldable support surface, such as a rotatable rubber
drum or rubber covered drum 14, below which is disposed a
translatable and rotatable drum 16, such as a steel drum.
Secured to a longitudinal circumferential segment of the
drum 16 is a strip of materlal 18 having a nodulose
- surface 19, such as sandpaper or emery cloth. The
securing means could be any conventional adhesive or
double-sided adhesive tape 20. Connected to the axis o~
drum 16 is a conventional hydraulic lift cylinder 22
which i8 synchronized by conventiona~ means such as a
timer (not shown). Actuation of the hydraulic lift
cylinder 22 will project or lift drum 16 toward drum 14.
As shown ln the enlarged view o the embossing station in
Figure 2, when the drum 16 is projected upward toward
support drum 14, ~he nodulose surface strip 18 secured to ~ -
the circumference of drum 16 is forced against film web 6 `~
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10855
~ 7
disposed in passage 15 formed between support drum 14 and
drum 16 thereby compressing the film into the support
drum 14. ~ach of the projected surface disturbances
forming the nodulose surface of strip 18 contac~s and
stretches a corresponding surface area of the film into
the rubber support drum 14 thereby imparting to film 6 a
plurality of permanent surface disturbances composed of
small stretched areas 21 pro~ecting from the surface of
the film 6 as shown in Figures 3 and 4. I~hen the film is
intended to be rolled on cores and packed in conventional
dispensing cartons for household use, the height and
projected surface area of each of the projected distur-
bances should be within the range as specified above.
, Draw rolls 28 and 30 pull the film web 6 from
p,assage 15 over idler spreader rolls,24 and 26. The film
web 6 is then fed,over roll 32 which contains cutting
means (not shown) for severing the film lengthwise into
two or more equal segments. The longitudinal cut film
web is further fed to roll 34 where it is then dispensed~
.
and wound onto a core 36 mounted on a rotatable mandrel
(not shown) which is disposed on a translatable and
rotatable ~urret 38. As shown in Figure 1, turret 38 has ,,
six cores 36, 40, 42, 44, 46 and 48. The turret is
operable such that when it is disposed to the left of
roll 34 (this position' not shown~l it is in a position
for.receiving a desired length of film 6 for winding on
: core 36, said core 36 being rotated in the direction
shown and being disposed adjacent a rider idler roll 52.
14.
:' .
- ~ :
7 1085S-l
After a desired length of film is wound on core 36, the
turret 38 is mov~.d to the right as shown in Figure 1
where a knife 50 severs transversely the film 6 across
the nodulose surface 23 thereby completing the wlnding
of the film 6 on core 36. Immediately upon severing ~he -~
film, the turret 38 is moved to the left and rotated
clockwise thereby advancing core 48 in position for
receiving the leading edge of the remaining film web 6.
The synchronization of the turret 38 with the drive feed
means for the film 6 (not shown) is conventional and is
disclosed, for example, in U.S, Patents 3,266,~4, ~: :
3,350,027 and 3,697,010.
The actuation of ~he hydraulic cylinder 22 is
timed by conventional means (not shown) so as to impart
a nodulose surface to the film web 6 at a location that
will be subsequently severed by the cutting knife 50 so
as to provide a nodulose leading edge portion for a fully
wound roll of film, said leading edge portion having a
plurality of surface disturbances consisting of small
stretched areas projecting from the surface and being
adapted for easy grasping to initiate the start o the
roll.
One of the ma~or benefits of this invention i9 ~.; ' ` .
that if the actuation of the embossing roll 16 gets out
of synchronization with ~he cutting means 50 so that the
film web is not severed transversely at the nodulose
surface of the film, then the apparatus can be shut down
: and in a few minutes the nodulose surface strip can be ~
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10855
~ ~ ~ 5'~'~7
remov~d and repositioned so as to restore proper synchro-
nization between the embossment and severing operations.
In addition, the nodulose surface strip is a relatively
inexpensive i~em that can easily be replaced when worn
out.
EXAMPLE 1
A 81" Poly Rewinder Machine 4769 obtained from
the Paper Converting Machine Company, Inc. of Green Bay,
Wisconsin was modiXled mainIy to the extent,that the
con~entional heated etched platen on the emboss drum was
replaced with three strips of emery cloth sized 40, 60
and 80 grit. Each of,the strips of emery cloth measured
3 inches in width and each'was secured to the emboss drum
using a double-sided adhesive tape, said strips spaced
apart approximately one inch. The modified machine was
as shown in Figure 1 and used a 62-inch (157.5 cm) wide
roll of polyethylene film as the supply roll. Following
the sequence as discussed above, the film web was then
fed over a rubber support drum and after passage of 99
feet (29.7 meters), the emboss drum w~s activated
thereby compressing the film against the support drum and
imparting to the film web three distinct nodulose contours ~'
each being ~hree inches in width. The film web was
severed longitudinally into five segments and then fed
onto cores in ~he manner as described above in conjunc- ,'
tion with Figures l and 2. After lO0 feet (30 meters) of '
film were'rolled on the cores, the cutting means of ~he ''
machine severed the film. This procedure was continued
until 200 rolls of film were produced. The rolls were
.
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16.
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10855
~ 7
examined and it was found that the substantially nodulose
surfaces of each roll of film were readily identifiable
and suitable for easy grasping since t~e cling charac- ~ -
teristics of the film at these surfaces were reduced. Of
the three nodulose surfaces on each roll of film, the
nodulose surface produced by the 40 grit emery cloth was
found to be slightly better or grasping than the nodulose ~ :
surfaces produced by the 60 grit and 80 grit emery cloths. ~ -;
.
EXAMPLE 2
. A 81" Poly Rewinder Machine 4769 obtained from ~.
the Paper Co.nverting Machine Company, Inc. of Green Bay,
Wisconsin was modiied mainly to the extent that the
conventional heated etched platen on the emboss drum was
replaced with a three inch wide strip of 40 grit size
: emery cloth (No. 40 Grit Carboundum Emery Cloth produced .~ . .
commercially by the 3M Company). The strip of emery
.cloth was secured .to the emboss drum using a double-sided
. .~ .
adhesive tape... The modified machine was as shown in ~.,~ .'';
. ,
Figure 1 and used a 62-inch (157,5 cm) wide roll of ' ',,
polyethylene film as the supply roll. Following
the sequence as discussed in Figures 1 and 2, the film
web was then fed over a rubber support drum,and after
passage of 99.9 feet (29.97 meters), the emboss drum was
acti~ated thereby compressing the film against the
support drum and imparting to the film web a three-inch
wide nodulose surface. .The film web was severed longi- .
tudinally into five segments and then fed onto, cores in :
the manner:as described above. A~ter 100 feet (30 meters3
of film were rolled on the cores, the cutting means of
- _~ 10855-1
the machlne ~evered transversely the film approximately
at the center of the nodulose surface of the film.
This procedure was continued until 200 rolls of film
were produced. The rolls were examined and it was
found that the substantlally nodulose surface of each
roll of film was readily identiflable and adapted for
easy grasping to initia~e the dispensing of the film
off the roll.
The rolls as taught herei.n are contemplated
particularly for use with standard one-use, consumer
type dispensing carton, in the known manner, Exemplary .
of such cartons would be the trunk lid style carton
as typified by the cartons shown in U.S. Patent Nos.
2,069,837, 2,226,477, 3,118,581, 3,129,870 and 3,549,066,
and the conventional flap lid style carton which is
illustrated in certsin various forms thereof in U.S.
Patent Nos. 1,972,069, 2,433,445, 2,4635375, 2,472,521,
2,624,501 and 2~888,181. ~ ;
It should be understood that the foregoing .
disclosure relates to :preferred embodiments of the ~.`
in~ention, and it is intended to cover all changes and ..
modificati.ons of the invention which do not depart from ;:.
the spirit and scope of the appended claims. ;: ;
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18. ~: :
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.: , - . ,. , : , . .. , ,, , . ,.. "
