Note: Descriptions are shown in the official language in which they were submitted.
2~1g~90
EMBOSSED CLOSURE PROFILE AND ASSOCIATED CONTAINER
YIELD OF THE INVENTION
The instant invention relates to improved
closure devices comprising two closure strips of the
type employed for flexible container such as plastic
bags. The outer contact surface of at least one of
the two closure trips (also commonly referred to as
"closure profiles") to be mated over a predetermined
length is provided with an embossed pattern whereby
the ease of mating the two closure strips is improved
and whereby improved manufacture of such closure
strips and related flexible containers is achieved.
DETAILED DISCUSSION OF THE INVENTION
It is well known in the prior art to form a
closure device having interlocking or adhesive
closure strips (a.k.a. "profiles") and more
particularly to form a closure device including two
closure profiles operable for being interlocked or
mated continuously over a predetermined length.
Generally, an interlocking closure device for
use in connection with flexible containers, such as
plastic bags and the like, are well-known and several
types are disclosed in the patent and non-patent
literature. Interlocking closure trips are well
known, as disclosed in U.S. Patent No. 4,212,337 and
Re. U.S. Patent No. 28,969. Similarly, adhesive
closure devices are well known as disclosed in U.S.
Patent Nos. 4,471,935 and 4,709,399.
It is also well-known that such closure devices
may be interlocked or mated by a slider or they may
be sliderless and of the type closed by use of human
fingers, including a human thumb, being slid along
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the outer contact surface for the predetermined
length to be interlocked or otherwise sated. When
such closure devices are sliderless they are
typically interlocked or mated by pressing together
the two closure profiles at one end followed by
running two fingers or a finger and thumb along
each of the outer surfaces of the two closure
profiles from one end to the other whereby the
closure is interlocked or mated over its
predetermined length.
Heretofore, the prior art has not considered the
nature of the outer contact surface of the
interlocking closure device as a means for improving
the ease of engaging, e.g., interlocking or mating,
the closure device or as to improving bag
manufacturing processes. The instant invention
addresses this issue and provides an embossed outer
contact surface to improve the ease of closure use
and the manufacturing handleability of the closure
and or container having the closure device as an
integral part.
SUMMARY OF THE INVENTION
Generally 6tated the instant invention relates
to a closure device having closure profiles for
becoming engaged, e.g., interlocked or mated by
adhesion or other means, when pressed together
wherein at least one closure profile has an embossed
outer contact surface selected so as to reduce the
contact area and surface friction on the outer
6urface of the closure profile. This reduction in
surface friction is a reduction when as compared to
the surface friction of the same surface without the
embossed pattern when a second surface, e.g., a human
finger or another bag surface, is slid across the
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respective surfaces. The reduction in contact area
of the area adjacent the closure device is a result
of having the embossed pattern and not the entire
surface as the area contacting the second surface.
The closure device may be connected to 6idewalls of a
container to form a container having a closure device.
one embodiment of the instant invention
comprises an interlocking closure device comprising
two closure profiles operable for being interlocked
continuously over a predetermined length (wherein
optionally the closure profiles may have different
colors, whereby the position of the profiles on a
container can be easily identified visually to
simplify the closing and opening of the container
and/or the complete occlusion of the closure profiles
can be easily verified visually) wherein the closure
profiles have outer contact surfaces having at least
one outer contact surface having an embossed surface.
A further embodiment of the invention is a
container comprising two flexible sidewalls, and an
interlocking closure device such as those disclosed
in U.S. Patent Nos. 4,186,786, 4,285,105 and
4,829,641, including two closure profiles operable
for being interlocked continuously over a
predetermined length connected to the sidewalls, the
closure profiles having different primary colors
selected to produce a predetermined 6econdary color,
whereby the complete occlusion of the closure
profiles can be identified visually easily and
wherein the closure profiles having outer contact
surfaces are further characterized as having at least
one of said two closure profiles having an embossed
outer contact surface or being contacted by a user
of the closure profile during interlocking of the two
closure profiles over a predetermined length whereby
the ease of passage of the user's fingers over the
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outer contact 6urface is improved over as a result of
providing the embossed pattern.
Another embodiment of the invention comprises a
container comprising two flexible sidewalls and an
adhesive closure device including two closure
profiles having outer contact surfaces operable for
beinq engaged continuously over a predetermined
length connected to the sidewalls, wherein at least
one outer contact surface has an embossed surface.
DESCRIPTION OF THE DRAWINGS
FIG. l i8 a perspective view of a flexible
container including a closure device in accordance
with the invention with embossed outer contact
surfaces adjacent the interlocking closure profiles;
FIGS. 2(a), 2(b), 2(c) and 2(d) are diagrammatic
and sectional views of closure devices in accordance
with the invention wherein embossed outer contact
surfaces are provided on interlocking closure
profiles;
FIG. 3 is a perspective view of a flexible
container having a gusseted bottom and including an
embossed closure device with embossed outer contact
surface in accordance with the invention;
FIG. 4 is a side elevational view of a closure
profile of FIG. l with an embossed outer contact
surface in accordance with the instant invention;
FIG. 5 is a perspective view of a flexible
container including a closure device with an embossed
outer contact surface wider than the width of the
base of the interlocking closure profile;
FIG. 6 is a side elevational view of the
flexible container with embossed closure device of
FIG. 5;
FIG. 7 is a schematic view of an apparatus for
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practicing one aspect of the invention;
FIG. 8 is an enlarged perspective view of an
embossing roll hown in FIG. 7; end
FIG. 9 is FIG. 17 of U.S. Patent No. 4,829,641.
DETAILED DESCRIPTION OF THE INVENTION
Generally stated the instant invention relates
to a closure device having closure profiles for
becoming engaged, e.g., interlocked or mated, when
pressed together wherein at least one closure profile
has an embossed outer contact surface. The embossed
outer contact surface provides a reduction in the
frictional forces between the outer surface of the
closure profile and another surface contacting said
tame, as compared to the friction between the same
surfaces without the embossed pattern. The closure
device may be connected to sidewalls of a container
to form a container having a closure device, such
flexible containers heretofore known in the prior
art.
The instant invention also relates to a
container including a closure device having two
closure profiles which are capable of being engaged
over a predetermined length by the fingers of a user
wherein the closure device $s characterized as having
an embossed closure profile so as to enable the user
to occlude the closure device easily by reducing the
friction experienced as the user finger are slid
along the outer contact surface of the closure
profile(s) during the engagement of the closure
profiles.
As used herein, the term "closure profiles" $s
used to designate two closure strips which are
designed to engage $n a locking or other mating
manner when pressed together and includes, but is no
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limited to, both adhesive closure trips and to
interlocking closure strips. Interlocking closure
strips are generally characterized as having
respective cross 6ections which enable the
interlocking closure profiles to be interlocked over
a predetermined length. The closure profiles may be
capable of being separated after engagement or may be
permanently engaged after being pressed together,
i.e., engaged. The closure profiles can include
flanged portions, rib portions and other features, as
hereto known in the art, and, further, can be
connected to a sidewall of a container or to other
surfaces to be engaged, e.g., portions of an article
of clothing or various types of covers.
As used herein, the term connected" includes an
integral combination obtained from extrusion through
the same die opening as well as adhesive or cohesive
or lamination connections.
As used herein, the term "outer contact surface"
is meant to designate the side of the closure profile
opposite the portion having the means for engagement
with a second closure profile. It is the "outer
contact surface" to which pressure is applied to
engage the closure profiles to provide a closure line
between two closure profile engagement surfaces. For
example, in FIGS. 2(a), 2(b), 2(c) and 2(d), the
outer contact surfaces are respectively designated
as: 22-A and 27-A; 24-A and 26-A; 27-A and 29-A; and
33-A and 34-A. As noted by reference to these
figures, the outer contact surface may be on the
closure profile itself or may be on the outer surface
of sidewall of a flexible container atop the closure
profile when the closure profile is placed on the
inside surface of the flexible container's
sidewalls. Similarly, the outer contact surface for
an adhesive closure i5 the non-adhesive side of the
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closure to which pressure is supplied on the two
mating closure profiles to adhere the two closures at
an interface of their respective adhesive engagement
surfaces.
As used herein the term "color" in relation to
color change closures and other portions having color
includes clear transparent and tinted transparent
and, 6imilarly, clear translucent, tinted translucent
and opague. The term "color" in reference to color
change closures is readily understood by reference to
U.S. Patent Nos.: 4,186,786; 4,285,105; and 4,82~,641.
The nature of the embossment to be provided to
the outer contact surface is characterized as being
selected 80 as to provide a reduction in the
coefficient of friction of the outer contact 6urfa~e
as a result of the embossed surface being provided to
the outer contact surface, i.e., the coefficient of
friction is reduced as compared to the same surface
sans the embossed pattern. This functional
relationship of the emboæsed outer contact surface to
the use of the closure device or a container having
such a closure device as a part thereof may be
achieved with a wide range of embossed patterns
formed by both physical and chemical treatments. The
embossed pattern may be a diamond pattern, (commonly
called a "criss-cross" pattern), grit blasted
pattern, various geometric patterns and non-geometric
patterns heretofore known in the art. A grit blasted
pattern is characterized by a micro roughness of the
surface of the embossing surface to be used to
provide the embossed outer contact surface. It has
also been observed that it is not necessary that the
embossed pattern be uniform on the entire outer
contact surface. For example, the embossed pattern
should be along a major portion of the length of
closure device (e.g., from one side to the other side
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2 0 1 g 3 O
edge when on a container) but need not be across the
entire width of each closure profile of the closure
device. It has been observed that during the
manufacture of a flexible container having a closure
device that the interactive nature of a closure
profile, the outer surface of the container sidewall
adjacent a closure profile and the embossing
characteristics of the embossing roll may create a
non-uniform embossed pattern on the outer contact
surface. This interaction may result in an embossed
pattern next to the closure profile area of the
closure device having a greater embossed pattern than
provided on the outer contact surface on the sidewall
directly atop the base of the closure device which is
on the inner surface of the container sidewall. This
effectively results in two different embossed
patterns owing to the differences in the actual depth
of the embossed pattern in the two areas of the outer
contact surface. Similarly, it is within the scope
of this invention to employ two or more different
embossing patterns on the same embossing roll or on
different embossing rolls whereby the outer contact
surface will have two or more different embossments,
e.g., both a diamond embossed pattern and a grit
blasted embossed pattern. Further, it has been
observed that a single embossed pattern may be
provided by superimposing one embossed pattern on
another embossed pattern to form a new embossed
pattern. For example, in one embodiment the
embossing roll is provided with a diamond pattern and
then provided with a second embossed pattern by grit
blasting the diamond pattern. In one embodiment a
diamond pattern is engraved in the embossing roll to
have a depth of about 0.010 to O.011 inches. Owing
to observed differences in the pressure of the
embossing roll against the flange adjacent the edge
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of the base of the closure profile as compared to the
pressure on the closure profile's base there i6 an
observed difference in the depth of the embossed
pattern in the outer contact 6urface, i.e., the
embossed pattern i6 not uniform. When the flanye is
about 0.~05 to 0.007 inch thick the aforementioned
embossing pattern will typically form a pattern 0.003
inch deep while the depth of the embossing pattern
directly atop the closure profile base portion will
typically be less than 0.003 inch thick. Such
non-uniform embos6ed outer contact 6urface areas are
suitable for use in the instant invention. Further,
when the embossed pattern is formed from a grit
blasted or a non-uniform pattern it may not be
convenient to measure either the depth of the
embossed pattern on either the embossing roll or the
embossed outer contact 6urface, although such an
embossed pattern may provide a suitably embossed
outer contact surface for the improvements
accomplished by the instant invention and,
accordingly, are within the scope of the instant
invention.
One embodiment of the instant invention
comprises an interlocking closure device comprising
two closure profiles operable for being interlocked
continuously over a predetermined length (wherein the
closure profiles may have different colors, whereby
the position of the profiles on a container can be
easily identified visually to simplify the closing
and opening of the container and/or the complete
occlusion of the closure profiles can be easily
verified visually) wherein the closure profiles have
outer contact surfaces having at least one outer
contact surface having an embossed surface.
Another embodiment of the invention is a
container comprising two flexible sidewalls and an
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interlocking closure device including two closure
profiles having outer contact surfaces operable for
being interlocked continuously over a predetermined
length connected to the sidewalls, wherein the
container comprises the closure profiles which may
be different colors whereby the position of the
profiles on the sidewall can be identified visually
easily to simplify the closing and opening of the
container) wherein at the two outer contact surfaces
of the closure profiles have an embossed outer
contact surface.
A further embodiment of the invention $s a
container comprising two flexible sidewalls, and an
interlocking closure device having two closure
profiles operable for being interlocked continuously
over a predetermined length and connected to the
sidewall, the closure profiles having different
primary colors are selected to produce a
predetermined secondary color, whereby the complete
occlusion of the closure profiles can be identified
visually easily and wherein the closure profiles are
further characterized as having at least one of said
two closure profiles having an embossed outer contact
surface for being contacted by a user of the closure
profile for interlocking the two closure profiles
over a predetermined length. Representative of said
interactive colored closure profiles which may be
employed in this embodiment are those disclosed in
U.S. Patent Nos. 4,186,786; 4,285,105 and 4,82g,641.
Another embodiment of the invention comprises a
container having a closure device wherein one or both
of the closure profiles of the invention includes a
flange portion (which may be embossed), rib portions,
spacer members, aligning members and other closure
related features heretofore employed in the use of
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closure devices and containers employing closure
devices. In addition, the bag body may be an
embossed film and may also have other features such
as write-on areas, gussets, lower corner tabs for
heat isolation, multiple compartments and the like,
as heretofore known on the art. In one embodiment of
the instant invention the embossed outer contact
surface is provided Jo as to extend from below the
closure profile, i.e., it least some portion of the
outer surface of the sidewall below the closure
profile has an embossed pattern, and extends from
this area to the mouth portions of the sidewalls
whereby both this lower sidewall portion the area
atop the closure profile and the flanges are embossed.
A further embodiment of the instant invention
comprising an adhesive closure device comprising two
closure profiles operable for being adhesively mated
over a predetermined length wherein the closure
profiles having outer contact surfaces have at least
one of the outer contact surfaces characterized as
having an embossed surface according to the instant
invention.
The invention accordingly comprises the features
of construction, combination of elements and
arrangement of parts which will be exemplified in a
construction hereinafter set forth and the scope of
the application of which will be indicated in the
claims.
Generally, closure devices and thermoplastic
films, such as those employed in the instant
invention can be made from the various thermoplastic
material, including polyethylenes (including, but
not limited to, the linear low density, medium
density and high density, although linear low density
polyethylene is preferred for its cost and overall
beneficial balance of chemical and physical
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properties), polypropylene, and other flexible
thermoplastic materials or the like and mixtures or
blends thereof. When the closure device is an
adhesive closure device an appropriate adhesive
material will be employed.
The thermoplastic material may alto contain one
or more additives as heretofore employed in the prior
art, including but not limited to, slip agents,
anti-block additives, anti-oxidants, colorants, dyes
and the like. It is believed that the instant
invention may beneficially result in a reduction in
the amount of certain additives hereto required to be
employed in the manufacture of closure devices and/or
containers having closure devices owing to the
observed reduction in friction of the outer contact
surface of the closure devices and containers of the
instant invention. For example, it is believed that
the use of the embossed outer contact surface may
result in a reduction in the amount of anti-block
and/or 51ip agent heretofore used.
The closure device can be of the type in which
one closure profile partially encircles or interlocks
in some fashion with the other closure profile
(commonly referred to as "interlocking closure
devices") or involves the engagement or mating of two
closure profiles by use of adhesive means (commonly
referred to as "adhesive closure devices").
Representat;ve of interlocking closure devices are
those shown in U.S. Pat. Nos.: Reissue U.S. Pat. No.
Re 28,969; 2,978,768; 3,038,225; 3,416,199;
3,338,284; 3,338,285; 3,565,147; 3,780,781;
4,561,108; 4,212,337; 4,363,345; 4,578,813;
4,362,198; 4,484,352; 4,516,268; 4,561,109;
4,733,778; 4,736,450; 4,787,880; 4,822,539 and
4,829,641. For
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example, the closure device can be of the type in
which each of the closure profiles includes a
plurality of hook portions and the closure profiles
engage to establish occlusion on a line of closure,
as shown in U.s. Patent No. 3,054,434, u.S. Patent
No. 4,212,337 and in U.s. Patent No. 4,829,641.
Adhesive closure devices are well known in the
prior art as is the use of such adhesive closure
devices on flexible containers. Representative of
such adhesive closure devices are disclosed in U.S.
Patent Nos.: 4,674,634; 4,708,70S; 4,709,399: and
4,741,935.
The use of an embossed outer contact surface for
closure profiles is believed to be advantageous for
both a sliderless closure device as well as a closure
device having a slider. The use of embossed outer
surfacPs for the closure profiles is advantageous
because the embossed outer contact surface acts to
reduce the surface friction on the outer contact
surface of the closure profile when beinq engaged by
use of sliding the fingers or a mechanical clider
over a predetermined length of the closure device.
It is also believed that this reduction in surface
friction arises from the reduction in surface area
contacted by the slider or user's finger(s).
The lower surface friction of the outer contact
surface is also beneficial in manufacturing steps
typically employed in the manufacture of bags having
a closure device. The folded web stock used for
manufacturing such bags closure bags") is typically
continuously manufactured by extrusion at a high bag
rate (i.e., bags/minute) with air or water cooling of
the bag film and closure device . the closure bags
are typically manufactured by cutting off successive
bags from a continuous folded web stock followed by
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stacking the finished closure bags by sliding or
placement of one atop another, wherein the outer
contact surfaces of the closure profiles of
respective closure bags come into contact as the
closure bags are 6tacked. When the outer contact
surfaces are smooth and glossy, they do not easily
61ide over each other, QVen when significant amounts
of slip agent and antiblock are present in the
thermoplastic material. When the closure bags are
manufactured at a high bag rate in conjunction with
an in-line extrusion process for the folded web
stock, the base of the closure profile i6 prone to
being "tacky" as a result of the relatively thick
closure profile not being sufficiently cooled,
because the slip agent in the thermoplastic material
has not had sufficient time to migrate to the surface
of the closure profile or bag film surface (commonly
referred to as "bleeding to the surface") and,
further, because antiblock additives have variable
effectiveness depending on processing variables.
When the outer contact surface has an embossed
surface the ease of sliding of the outer contact
surface of another closure bag is substantially
improved. The use of the embossed outer contact
surface in the manufacturing process provides
improved processing of the closure bags which results
in increased rates of manufacture and ease of
handling of the closure bags during manufacture. In
addition, it is believed that the embossed outer
contact surface wends to reduce the sticking of the
outer contact surfaces as between closure bags after
the closure bags have been 6tacked and aged for a
period of tiDe.
In carrying the invention into effect, certain
embodiments have been selected for illustration in
the accompanying drawings and for description in this
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specification, reference being had to FIGS. 1 to 9.
Although FIGS. 1 to 9 show the closure device as an
interlocking closure device, it will be understood
that other closure devices may be substituted for the
interlocking closure device in accordance with the
instant invention.
FIG. 1 shows a typical flexible container 10
formed from a thin, transparent, plastic film which
has been folded to define a bottom portion 11 and
heat sealed along vertical side edges 12 to form a
pouch.
The sidewalls 13 extend beyond a sliderless
closure device 14 to provide flanges 15 and mouth
portions 16 and 17 to simplify the opening of the
closure device 14.
The closure device 14 includes closure profiles
18 and 19 (closure profile 19 shown with an embossed
outer contact surface) and may comprise any closure
device including those closure devices incorporated
above by reference thereto. In accordance with the
art, the end portions of the closure profiles 18 and
19 may be connected to each other although it is
Xnown that such end portions may be left unconnected.
The closure profiles 18 and 19 may be different
colors or haze colored ribs so as to be easily
identified visually, although such is not required to
achieve the improved ease of closing achieved by
embossing the outer contact surfaces of the closure
profiles. The sidewalls 13 are typically transparent
but could be made translucent with colors or tints,
or could be themselves embossed or be made opaque.
If the closure device is to be a color change closure
device and sidewalls 13 are to be opaque, then it is
advantageous that at least one of the closure
profiles should be a color which can be easily
distinguished from the 6idewall region adjacent to
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it U.S. Patent Nos. 4,186,786 and 4,829,641
aforementioned, disclose flexible containers having
such color change closure devices.
Preferably, the sidewalls 13 are transparent or
translucent at least in the region adjacent to the
closure profiles 18 and 19 and may have an embossed
pattern.
FIGS. 2(a), 2(b), 2(c) and 2(d) show different
embodiments of the interlocking closure devices of
the instant invention. FIG. 2(a) shows closure
profiles 27 and 22 which are flangeless and may be
connected to opposite inside or outside sidewall of
a container or other surface and have outer contact
surfaces 22-A and 27-A, respectively. FIG. 2(b)
shows closure profile 23 including a flange portion
24 and flangeless closure profile 26, having outer
contact surfaces 24-A and 26-A, respectively. FIG.
2(c) shows flangeless closure profile 27 and closure
profile 28 including a flange portion 29, having
outer contact surfaces 27-A and 29-A, respectively.
FIG. 2(d) show closure profiles 31 and 32 including
flange portions 33 and 34, respectively, and having
outer contact surfaces 33-A and 34-A, respectively.
Although not shown in FIGS. 2(a), 2(b), 2(c) and 2(d)
the closure profiles may be employed on, i.e.,
affixed to, the inside or outside of the container
sidewalls or when the closure profiles are suitably
fielected employed on the outer surface of the
container sidewalls with the container sidewalls
being between the two closure profiles when engaged,
e.g, interlocked. In thi& later embodiment, the
outer contact surfaces 22-A and 27-A of closure
profiles 22 and 27 (referring to FIG. 2(a), i.e., the
surface not having the hook projections for
interlocking said closure profiles) are embossed with
the selected embossed pattern.
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Preferably, the flange portion 15 is clear
transparent, but the flange portion could be tinted
60me color or even be opaque. The flange portion
could be embc~-sed (not shown) and/or have a
predetermined color while the remainder of the
closure profile i6 transparent, translucent, opaque
or combinations of the aforementioned.
In the instant invention the portion of the
closure profile or container sidewall associated with
the closure profiles for engagement over a
predetermined length by contact with a mechanical
slide or the human hand will have at least one
closure profile having an embossed pattern(s)
associated with the outer contact surface.
FIG. 3 shows a container 36 similar to the
container 10, but including a gusseted side 37 with
rectangular bottom 37-A to provide a stand-up,
gusseted interlocking closure bag.
FIG. 4 shows closure profile 22 of FIG. 2(a) in
which the female closure profile 22 having borders 38
and 39 on opposite sides of portions of the male
closure profile 27 showing embossed pattern 22-A when
closure profiles 22 and 27 are interlocked.
Because in one embodiment the closure profiles
22 and 27 shown in FIG. 1 are different colors 50 as
to provide a color change closure device, the
completeness of the occlusion can be easily verified
visually by observing the relationship between the
continuous borders 38 and 39 and the embossed region
22-A, wherein, with respect to the closure profile 22
and outer contact surface 22-A, the selection of the
embossed pattern is made 80 as not to interfere with
visual observation of the color change. Preferably,
the closure profiles 22 and 27 should be contrasting
colors to optimize the ease in visually identifying
the completeness of the occlusion such as described
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in U.S. Patent No. 4,829,641. In one embodiment the
closure profiles are different colors but do not
provide a third color upon engagement.
Referring to FIGS. 1 and 2(a), in one embodiment
the interlocking closure device comprises closure
profiles 18 and 19 of the type shown in FIG. 2(a),
the sidewall of a container used in connection with
closure profiles 22 and 27 comprise a color change
closure device and the sidewall6 should preferably be
transparent or translucent at least in the region
adjacent to the closure profiles 22 and 27 to improve
color charge perception. Closure profiles 22 and 27
in this embodiment can be primary colors and
sufficiently translucent so that the occlusion of the
closure profiles 22 and 27 produces a viæible
secondary color. Thus, the completeness of the
occlusion can be determined visually easily by
observing a continuous region of the secondary color
bordered on each side by one of the primary colors
depending upon the side being viewed.
FIG. 5 shows a typical flexible container 40
formed from a thin thermoplastic film which has been
folded to define a bottom portion 41 and heat sealed
alonq vertical side edges 42 to form a bag and having
an embossed outer contact 6urface comprising the
outer surface of the bag film and having a width
wider than the width of the base of the closure
profile affixed to the inner sidewall surface. The
film may also be tinted or embossed if so desired.
The sidewalls 43 extend beyond a closure device
48 to provide mouth portions 46 and 47 to simplify
the opening of the closure device having closure
profiles 48-A and 48-B (shown in FIG. 6). A flange
portion 45 is shown below the mouth portions 46 and
47 and may have ribs or ridges and the flanges may be
themselves embossed or contain an anti-slip surface
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6uch as described in European Patent Application
83102845.1, published September 28, 1983, -
incorporated herein by reference.
Closure device 48 includes two clc,ure profiles (only
closure profile 48-B shown in FIG 5) cld is
preferably a closure device as described in U.S.
Patent No. 4,829,641. In accordance with the prior
art, the end portions of the closure profile may be
connected to each other, although it it known that
such may be left unconnected.
The closure profiles of closure device 48 may be
different colors to be easily identified visually,
although uch is not required to achieve the improved
ease of closing, i.e., interlocking achieved by
embossing the outer contact surfaces of the closure
profiles. The sidewalls 43 are typically transparent
but could be made translucent with colors or tints,
or could be themselves embossed or even be made
opaque. If the closure device is to be a color
change closure device and sidewalls 43 are to be
opaque, then it is advantageous that at least one of
the closure profiles should be a color which can be
easily distinguished from the sidewall region
adjacent to it. U.S. Patent Nos. 4,186,786 and
4,829,641 disclose container having such colored
closure strips.
Preferably, the sidewalls 43 are transparent at
least in the region adjacent to the closure profiles
of closure device and may be transparent with an
embossed pattern.
FIG. 6 is a side elevational view of a portion
of FIG. S showing flange 45, mouth portion 47,
closure profile 48-B connected to sidewall 43 wherein
the embossed outer contact surface 49 is on the
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surface of the sidewall adjacent closure profile 48-B
and is shown as being wider than the closure profile
with the embossed outer contact surface extending
both above and below the width of the base of the
closure profile, although such is not required. In
addition, the flange area may be embossed (not shown)
up to mouth portion 47.
FIG. 7 6hows a schematic view of apparatus for
continuously embossing or engraving the outer contact
surface associated with a closure device, 8.g., an
interlocking closure device, and/or a closure bag.
There is shown a reclosable container 6toc~ supply 51
(source not shown) which may be a folded web stock or
a closure profile supply 51 (source not shown) being
fed to the nip of two pull rollers wherein one roller
is a resilient rubber-backed roller 52 and one roller
i8 a non-yielding embossing roller 53 having on its
surface an embossing pattern 54 on one portion
thereof as shown in FIG. 8. When the closure device
is an interlocking closure device, the embossing
roller 53 also preferably has a peripheral groove 55,
as shown in FIG. 8, located around its circumference
to accommodate the closure profile element and to
avoid damage to the closure profile(s) during
embossing. Similarly, when ribs or spacing portions
are provided it is preferred to provide a groove (not
shown) for accommodating such to avoid damage to such
during the embossing process. The other portion of
the embossing roller is shown as smooth, as depicted
at surface 56 in FIG. 8, although such could be
embossed if it is desired to provide the sidewall (6)
with an embossed surface. As shown in FIG. 7,
container 6tock supply 51 or tape supply 51 i6 fed to
the nip of rubber-backed roller 52 and embossing
roller 53 whereby an embossed pattern is produced on
the contact surface of the container stock supply 51
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associated with closure profile 31 and, optionally,
on the flange portion of the container sidewall. An
embossed pattern 54, shown a6 a diamond pattern in
FIG. 8, i6 provided on the outer contact surface.
As shown in FIG. 7, the emboæsed outer contact
surface is provided with the embossed pattern by
feeding reclosable container stock or closure
device between the nip of a pair of rollers wherein
at least one of the rollers bears an embossing or
engraving pattern thereon, end one or both rollers
have grooves therein to accommodate the occludable
closure profiles of the interlocking fastener device
to thus avoid damaging the occludable closure
profiles. It should be noted that it is not
necessary that the embossing step be carried out at
the point in the process where the film or closure is
still warm. Alternatively, a heated embossing roller
may be provided at another point in the manufacturing
process whereby the embossed pattern may be formed on
the outer contact surface.
Following the embossing step, the male and
female closure profiles may be occluded by passing
through occlusion rollers and the occluded container
stock or interlocking closure profiles is then
directed to a wind-up device for storage, or is
directed to further processing eguipment.
The improved containers of this invention are
provided with an embossed outer contact surface for
use by the user, thereby providing easier closure of
the container. In one embodiment the flange surface
areas may be provided with embossing or engraving on
the flange for providing improved ease in opening the
container.
- Typically, when the container is a food storage
container, the container 10 (shown in FIG. l width
is about 10-9/16 inches and the height is about
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11-1/2 inches. The dimensions of various
commercially available bags are well known. The
closure device is typically located about 5/8 to one
inch below the top edge of the grasping flanges.
Referring to FIG. 1, operation of the container
according to the invention i8 as follows:
A user in the process of closing the container
10 with closure profiles 18 and having an embossed
outer contact surface can interlock an end portion,
adjacent side edge 12, of the two closure profiles at
one end and than easily interlock the closure
prsfiles over a predetermined length by running the
closure profiles between a thumb and a finger along
the two closure profiles from one side edge to the
other side edge. The relatively small spacing
between closure profiles results in alignment from
the small portion initially pressed together as to
result in easily interlocking the closure profiles by
sliding the thumb and finger along the embossed outer
contact surfaces of the closure profiles. The
embossed outer contact surface it an excellent
sliding surface for the thumb and/or finger. The
user may then open the bag by separating the top
edges by grasping the flanges and pulling them apart
to disengage the closure profiles from each other.
The embossed outer contact surface reduces the
frictional forces experienced by the user as pressure
is applied to the outer contact surface as the user
slides a finger and/or thumb over the outer contact
surface(s) of the closure profile.
The containers and closure devices employed in
this invention may be prepared by any suitable
manufacturing method, including that disclosed in
U.S. Patent No. 4,676,851. For example, each
closure profile can be manufactured as
I.
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a strip for subsequent attachment to a film by the
use of appropriate attaching means. Typically, a
thermoelectric device can be used to apply heat to a
film in contact with a closure strip to cause a
transfer of heat through the film to produce fusing
at the interface of the film and the closure 6trip.
The fusing of the film and the closure profile may
also be effected by coextrusion of a molten closure
profile onto a molten film or may be effected by the
use of hot melt adhesives, hot air sealing, or other
methods such as ultrasonic heating.
The manufacturing operation, broadly speaking,
involves adhering each closure profile, e.g., an
interlocking cloture profile, which i6 in a molten or
non-molten state, to a molten or non-molten film of
thermoplastic material. The process is typically a
continuous process and employs a slot film casting
station and at least one grooved lay-on roll and at
least one roll for applying the embossment to the
outer contact surface. In one embodiment, an
interlocking closure device having closure profiles
with flange portions are fed to lay-on rolls having
circumferential grooves therein to accommodate the
contours of the closure profiles. A molten
thermoplastic film is extruded onto a rotatable
casting cylinder positioned opposite the lay-on rolls
so that the thermoplastic film becomes fused to the
flange portions of the closure profiles, and
thereafter the combination of thermoplastic film and
closure profiles is cooled. (Alternatively, closure
profiles, and optionally, ribs and the like, may be
directly extruded onto the plastic film). The lay-on
rolls, may be as wide as or wider than the specific
closure profile to be affixed to the molten
thermoplastic film or may be wider 80 as to contact
the other portions of the thermoplastic film.
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Further, the lamination pressure exerted by the
lay-on rolls on the casting cylinder, with the
closure profiles and thermoplastic film therebetween,
may be controlled by spacing means such as jacking
bolts or air cylinders which prevent damage to the
closure profiles and the thermoplastic film. The
casting cylinder is rotated at substantially the same
surface speed as the fed closure profiles, whereby
the closure profiles are laminated to the
thermoplastic film cast on the casting cylinder. The
combination of closure profiles and thermoplastic
film is then advanced to further cooling means such
as a chill roll. The afore-described method for
providing plastic film with occludable closure strips
fused thereto, pursuant to U.S. Patent No. 4,676,8S1,
m a y b e e m p 1 o y e d
herein to provide the sidewalls of the container with
at least one embossed urface such as embossed outer
contact surface, as shown in FIG. 1 (in relation to
closure profile 19) or outer contact surface 49 as
shown in FIG. 5 and FIG. 6. The embossed outer
contact surface may be obtained by providing an
embossing or engraving pattern on at least one
portion of the aforementioned casting cylinder,
forming or feeding preformed closure profiles having
flange portions to a rotatable circumferentially
grooved lay-on roll so that the unoccluded closure
profiles extend into the grooves of the lay-on roll,
extruding a molten thermoplastic film onto the
rotatable casting cylinder positioned opposite the
lay-on roll so that the molten thermoplastic film
fuses to the flange portions of the closure strips,
and thereafter cooling the laminated composite of
thermoplastic film and closure profiles.
The embossing or engraving pattern on at least
one portion of the surface of the casting cylinder
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2018~0,
may be one as earlier discussed, e.g., a diamond
pattern as depicted in FIG. 7. The other portion of
the surface of the casting cylinder can be smooth or
may be embossed to provide an embossed pattern to the
sidewalls of a flexible container if such is being
formed. In addition, the surface of the casting
cylinder may have more than one portion thereof
having an embossing or engraving pattern thereon,
i.e., two or more different embossed patterns. In
any event, as the molten plastic film it extruded
onto the casting cylinder having an engraving or
embossing surface portion, and as the molten
thermoplastic film contacts the closure profiles
carried by the lay-on roll, pressure contact
therebetween fuses the cast molten plastic film to
the closure profiles and also embosses the opposite
surface of the cast film adjacent the closure profile
to provide an embossed outer contact surface.
As shown in FIG. 5 herein with respect to
embossing roller 33, the engraving or embossing
pattern on the Qurface of the casting cylinder is
shown as closely spaced diagonal criss-crossed lines
and has intervening smooth areas (commonly referred
to as a "diamond pattern"). The engraving or
embossing pattern on the surface of the casting
cylinder may be provided with from between about 14
to about 56 lines per square inch in each diagonal
direction and in one embodiment with between about 30
to about 40 lines per inch in each diagonal
direction. An embossed pattern for an embossing roll
suitable for use in providing an embossed outer
contact surface in accordance with the instant
invention has an embossed diamond pattern having
about 36 lines per inch in each diagonal direction
(available as diamond pattern P36 from PAMARAC0,
Inc., 209 East llthe Avenue, Roselle, New Jersey,
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followed by grit blasting the diamond pattern using
PAMA 14 (available from PAMARACO, INC.), chrome
plating the grit blasted diamond pattern and then
again grit blasting (per PAMA 14) the
chrome-plated-grit-blasted diamond pattern.
The manufacturing method may al80 employ
81 itters to remove trim such 8S edge beads and to
slit the bag stock to provide multiple products
having closures. For example, a pair of deoccluded
interlocking closure profiles may be fed into the
grooving of a plurality of rubber-covered lay-on
rolls which align the closure profiles into the
proper lateral positions prior to contact and
lamination with the molten cast thermoplastic film.
Obviously, any number of such lay on roll
arrangements may be employed on a common shaft.
FIG. 9 is Figure 17 of U.S. Patent No.
4,829,641 with the numbering shown
thereon being as shown in U.S. Patent No. 4,829,641.
In one embodiment of the instant invention the
interlocking closure device of FIG. 17 is employed as
the closure device on a container, such as shown in
FIG. 1 or FIG. 5 of the instant application. An
embossed surface is provided on the outer contact
surface of sidewalls at flange portions 352 and 382,
whereby the outer contact surfaces (the non-closure
profile sides of sidewalls at 352 and 382) have an
embossed 6urface according to the instant invention.
Various alternatives may be practiced pursuant
to this invention. For example, each closure profile
portion may be extruded directly, into the area
previously described as the lanination area,
simultaneously with the cast thermoplastic film while
providing appropriate embossing and cooling means
therefor. These molten thermoplastic streams are
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201 8t~90
combined to form an integral thermoplastic web which
is then cooled and processed further. As in the
aforementioned method, the casting cylinder may be
provided with an embossing or engraving pattern on a
portion of its surface and produce the embossed outer
contact surface of the closure profile on the outer
surface of the sidewall of the ultimate container.
Preferably, at least a portion of the casting
cylinder has a matte, textured, embossed, or engraved
surface to provide the desired embossed outer contact
surface of the closure profile areas for the
container, although a separate embossing step may be
employed. Alternatively, the embossed pattern on the
outer contact surface may be provided by means of
heated embossing roll after the bag stock for
manufacturing the closure bags is formed or the
closure bags are manufactured. The container stock
may also be fed directly to a container
forming/cut-off mechanism such as a bag-making
machine.
Containers prepared in accordance with this
invention may be used in the packaging and storing of
a variety of articles and products.
Moisture-containing foods including fruit such as
apples, pears, peaches, plums, tomatoes; meats:
vegetables 6uch as carrots, peas and string beans may
be conveniently packaged and maintained in sanitary
condition in such containers.
The following example is provided to illustrate
the instant invention and are not intended to be
limiting thereof.
EXAMPLE 1
The reduction in the coefficient of friction of
the outer contact surface of the closure profile was
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` 20~90
determined by contacting the outer contact surfaces
of two closure profiles one on top of the other and
dragging one relative to the other. The lower
closure profile is secured in a support grooved to
accommodate and position the closure profile. The
upper closure profile is in a similar grooved support
(~sledn) jut is provided with wheels aligned to make
the sled move parallel to the closure profile mounted
therein. the wheels are positioned to follow grooves
in the support for the lower closure profile, these
grooves being parallel to the lower closure profile
and positioned laterally so that the upper and lower
closure profile outer contact surfaces rest against
each other. The wheels on the sled are elevated so
that only those on one side of the sled can rest on
the bottom of the wheel groove at a given time while
the wheels on both side still maintain guidance from
the sides of the wheel grooves. In this way the
wheels guide the sled without reducing the load
applied to the upper and lower closure outer contact
surfaces in contact and being tested. Further, the
depth of the closure grooves and orientation of the
closure profiles are adjusted such that the tested
outer contact surface is only that at the base of a
closure profile and does not include flanges or other
surface areas not directly atop the base of a closure
profile. A measured load (200 grams) is applied my
the upper support, i.e., sled, and the resistance to
dragging the sled measured and the Coefficient Of
Friction (COF) calculated as a ratio of drag force to
applied load for each sample. A total of three (3)
test specimens were evaluated for each of Samples A,
B and C, the range of individual points recorded and
an average value calculated. All sample specimens
were made with the male or female closure profile as
shown in FIG. 17 of U. S. Patent No. 4,829,641.
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Sample A was made with a mirror surface casting roll
with no engraved pattern and represents the prior art
and a comparative control sample. Sample A was
manufactured using a linear low density polyethylene
resin having a high concentration of slip agent
(about 1500 ppm by weight erucamide) and an
antiblocking additive (10,000 ppm by weight of a
diatomaceous earth). Sample B was manufactured the
same as aforementioned Sample A except the 81ip agent
concentration was 700 ppm and the antiblock
concentration was 4500 ppm. The lower concentrations
of slip agent and antiblock would be expected by
those skilled in the art to result in significantly
higher Coefficient of Friction for the bag surfaces.
Further, the outer contact surface of Sample B of the
closure device was melt embossed. The embossed outer
contact surface of Sample B specimens was on the
outer surface of the container sidewall and included
the area atop the base of the closure profile and
about 0.5 inch on either side of the base of the
closure profile, although the area tested was only
the width of the closure. FIG. 6 shows an embossed
outer contact surface on the outer surface of the
sidewall wherein the embossed pattern extends above
and below the width of the base of the closure
profile). The embossed pattern for Sample B is
characterized as a diamond pattern having 36 lines
per inch in each diagonal direction (available as
diamond pattern P36 from PAMARAC0, INC., 20~ East
llthe Avenue, ~oselle, New Jersey), followed by grit
blasting the diamond pattern using PAMA 14 (available
from PAMARACO, INC.), chrome plating the grit blasted
diamond pattern and then grit blasting (again using
PAMA 14) the chrome-plated-grit-blasted diamond
pattern a second time. A third Sample C was evaluated
wherein Sample C comprised the embossed male closure
profile of Sample B and the non-embossed female closure
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- - - 201~3~
profile of Sample A. The 6pecimens of Samples A, B
and C were aged about three (3) weeks after being
made before testing whereby the 61ip agent is
believed to have migrated to the surface of the outer
contact curface. The following results were obtained:
TABLE Il
Coefficient of Friction
Test 1 Test 2 Test 3
Sample (Av. Ranqe) (AY. RanaeL (Av. Ranae~ Averaae
A 0.475 0.36 0.43 0.422
(0.365-0.62) (0.31-0.49) (0.295-0.605)
B 0.145 0.120 0.125 0.130
(o.100-0.21) (0.07-0.18) (0.08-0.18)
C 0.155 0.175 0.195 0.175
(0.13-0.21) (0.145-0.24) (0.15-0.27)
1 The "Final Average" value is the average of the
average values of Test 1, Test 2 and Test 3.
From the above results it is evident that the
addition of the embossed pattern on the outer contact
surface of the female and/or male closure profile
results in a significantly reduced COF. In fact, the
COF between unembossed surfaces gave an average COF
value of 0.422, the average COF value of the embossed
female and male closure elements were 0.130 and when
only one embossed closure profile was present the
average COF value was 0.175.
The considerably lower COF values indicate
improved ease of closure for a closure device when a
61ider or user's hand i8 drawn across the outer
contact surface to cause the closure profiles to
engage, or, as in the instant example to interlock.
The ~ignif~cantly lower COF is also beneficial
in the manufacturing processes typically employed in
the manufacture of bags having a closure device.
When closure bags are made in conjunction with an
in-line extrusion process for the folded web stock
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2~18~
(i.e., a fold cver web of film with mating closure
profiles spaced near the open edges) wherein the
closure bag is formed between about 20 and about 120
seconds after the web of film and closure profiles
ore extruded, the Coefficient of Friction of the
outer contact surfaces are both higher and more
variable than those observed when the same specimens
are aged. Accordingly, such on in-line process will
benefit to a significant extent from the reduction in
the Coefficient of Friction of the embossed outer
contact surface, since the 61ip agent present in the
thermoplastic material will not have had sufficient
time to migrate to the surface of the outer contact
surface. Since the closure bags are manufactured by
cutting off successive bags and stacking one atop
another, the outer contact surfaces of the closure
profiles come into contact as the closure bags are
stacked and an improvement in the ease of sliding the
outer closure surface of one bag over the outer
closure surface of another closure bag substantially
improves the manufacturing process. This improved
processing of the closure bags results in increased
rates of manufacture and ease of handling during the
manufacturing process.
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