Note: Descriptions are shown in the official language in which they were submitted.
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RECLOSABLE STORAGE BAG WITH COLOR CLOSURE INDICATOR
FIELD OF THE INVENTION
The present invention relates to closures such as those commonly employed on
flexible
storage bags, particularly those suitable for use in the containment and
protection of various
items including perishable materials.
BACKGROUND OF THE INVENTION
Flexible storage bags for use in the containment and protection of various
items, as well
as the preservation of perishable materials such as food items, are well known
in the art. Such
bags typically comprise a rectangular sheet of polymeric film folded upon
itself and sealed along
two edges to form a semi-enclosed container having two flexible opposed
sidewalk, three sealed
or folded edges, and one open edge. A closure integrally formed with the bag
such as an
interlocking rib-type seal or separately provided such as a plastic or paper-
clad-wire tie completes
the containment assembly.
As utilized herein, the term "flexible" is utilized to refer to materials
which are capable of
being flexed or bent, especially repeatedly, such that they are pliant and
yieldable in response to
externally applied forces. Accordingly, "flexible" is substantially opposite
in meaning to the
terms inflexible, rigid, or unyielding. Materials and structures which are
flexible, therefore, may
be altered in shape and structure to accommodate external forces and to
conform to the shape of
objects brought into contact with them without losing their integrity.
Flexible storage bags of the
foregoing variety are typically formed from polymeric film, such as
polyethylene or other
members of the polyolefin family, in thicknesses of between about 0.0002
inches to about 0.002
inches. Such films are frequently transparent but sometimes are opaque and/or
colored.
Flexible storage bags of the currently commercially available variety provide
a means of
conveniently storing a wide range of objects and materials in a generally
disposable containment
device. Many commercially available flexible storage bags utilize mechanical
interlocking seals
to achieve closure of the bag opening, and some such bags additionally employ
a sliding
mechanical closure to improve the ease of opening and closing mechanical
interlocking seals.
With either type of mechanical interlocking seal, there remains the issue of
determining whether
complete closure has in fact been completed across the mouth of the bag to
achieve the desired
completion of the closing operation.
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Currently there are two color change systems on the market for such closures.
One
system involves the interlocking of blue and yellow elements to produce a
green seal, while the
other involves the interlocking of red and blue elements to produce a purple
seal. These are
accomplished by simply dying each side of the translucent zipper closure a
different primary
S color so that when they are pressed together to seal, light passing through
the closure produces an
apparent color which is the secondary color formed from the original two
primary colors. While
such systems do provide a color change indication of when sealing has been
accomplished, under
many lighting conditions it is difficult to discern whether the color seen by
the consumer is
produced by interlocking of the seals or by light passing through elements
which are merely
closely superimposed. Moreover, those individuals with visual impairments such
as color
blindness or reduced visual acuity may not correctly interpret the condition
of the seal by vision
alone.
Accordingly, it would be desirable to provide a closure which provides for a
positive
indication of when a complete closure has been achieved.
SUMMARY OF THE INVENTION
The present invention provides a flexible storage bag having an opening and a
closure
system for the opening, wherein the closure system provides a high contrast
color indication
when complete closure of the closure system has been achieved. The closure
system may be a
mechanical interlocking seal or an adhesive-based closure system. The high
contrast color
indication may be a change from colorless to colored, from white to black,
and/or from
translucent to opaque.
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particularly pointing out and
distinctly
claiming the present invention, it is believed that the present invention will
be better understood
from the following description in conjunction with the accompanying Drawing
Figures, in which
like reference numerals identify like elements, and wherein:
Figure 1 is an elevational view of a flexible storage bag employing a closure
in
accordance with the present invention;
Figure 2 is an elevational view of another flexible storage bag in accordance
with the
present invention;
Figure 3 is a perspective view of a further flexible storage bag in accordance
with the
present invention; and
Figure 4 is an elevational view of yet another flexible storage bag in
accordance with the
present invention.
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DETAILED DESCRIPTION OF THE INVENTION
Figure 1 depicts a presently preferred embodiment of a flexible storage bag 10
according
to the present invention. In the embodiment depicted in Figure 1, the flexible
storage bag 10
S includes a bag body 20 formed from a piece of flexible sheet material folded
upon itself along
fold line 22 and bonded to itself along side seams 24 and 26 to form a semi-
enclosed container
having an opening along edge 30. Flexible storage bag 10 also includes a
mechanical closure
system 40 located adjacent to edge 30 for sealing edge 30 to form a fully-
enclosed container or
vessel. Bags such as the flexible storage bag 10 of Figure 1 can be also
constructed from a
continuous tube of sheet material, thereby eliminating side seams 24 and 26
and substituting a
bottom seam for fold line 22. The mechanical closure system 40 includes an
interlocking
mechanical seal of any suitable conventional design.
In accordance with the present invention the closure system 40 provides a high
contrast
color indication when complete closure of the closure system has been
achieved. As utilized
herein, the term "high contrast color indication" is used to refer to refer to
a change in visual
appearance that is categorical rather than a matter of degree. For example,
the high contrast color
indication may be a change from colorless to colored, from white to black,
and/or from
translucent to opaque, rather than a change from one color to another of the
same degree. The
high contrast color indication may be visible from one or both sides of the
bag.
With continued reference to Figure 1, the closure system 40 provides a high
contrast
color indication in the form of a change from the initial
clear/transparentJcolorless appearance
indicated by the numeral 60 to the purple color appearance indicated ':~ ~.r
the numeral 50 when the
hand 70 of the consumer is translated along the closure system 40 to interlock
the opposing
elements of the mechanical interlocking seal.
Figure 2 illustrates a similar flexible storage bag 10 wherein the high
contrast color
indication is in the form of a change from the initial white appearance
indicated by the numeral
60 to the black color appearance indicated by the numeral 50.
Figure 3 illustrates a flexible storage bag 10 which utilizes a pressure-
activated adhesive-
based closure system 45 which provides a high contrast color indication in the
form of a change
from the initial clear/transparent/colorless appearance indicated by the
numeral 60 to the green
color appearance indicated by the numeral 50. A suitable adhesive-based
closure system
comprises a selectively activatible adhesive-bearing structure protected from
inadvertent contact
by a plurality of compressible, collapsible protrusions surrounded by adhesive
which provides a
secure closure seal upon activation. Suitable representative three-dimensional
materials of this
variety which include a thin layer of pressure-sensitive adhesive protected
from inadvertent
contact, as well as methods and apparatus for manufacturing them, have been
developed and are
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described in detail in commonly-assigned U.S. Patent Nos. 5,662,758, issued
September 2, 1997
to Hamilton and McGuire, entitled "Composite Material Releasably Sealable to a
Target Surface
When Pressed Thereagainst and Method of Making", and 5,871,607, issued
February 16, 1999 to
Hamilton and McGuire, entitled "Material Having A Substance Protected by
Deformable
Standoffs and Method of Making", and commonly-assigned, co-pending U.S. Patent
Application
Nos. 08/745,339 (allowed), filed November 8, 1996 in the names of McGuire,
Tweddell, and
Hamilton, entitled "Three-Dimensional, Nesting-Resistant Sheet Materials and
Method and
Apparatus for Making Same", 08/745,340, filed November 8, 1996 in the names of
Hamilton and
McGuire, entitled "Improved Storage Wrap Materials", all of which are hereby
incorporated
herein by reference.
Figure 4 is a flexible storage bag 10 similar to that of Figure 1, but
employing a sliding
mechanical closure (not numbered) as a mechanism for closing the interlocking
mechanical
closure 40. The sliding mechanical closure may be of suitable conventional
design for the type of
interlocking mechanical seal employed.
Any suitable means for generating the high contrast color indication
consistent with the
materials utilized for bag and closure system construction, the intended
contents of the bag (i.e.,
food grade, sterile, etc.), and the environmental conditions foreseen may be
utilized. Colors and
indications can be selected depending upon the color of the bag components,
bag contents, and
chemical/structural approaches utilized.
For example, the high contrast color indication from translucent to opaque or
black can
be accomplished through opposing surfaces having coatings that when pressed
together blocked
enough light to appear much darker when together. Another more exotic approach
would be to
use coatings that polarized light so that when they were separate they
appeared completely clear
but when together would block sufficient light transmission to make them
appear opaque.
Another suitable approach to generating a high contrast color indication would
be to use
a system of chemicals that when contacted created a color via chemical
reaction. One such
system would include a microencapsulated phenolthalene solution sprayed on one
side of a seal
and a microencapsulated basic solution sprayed on the other. When the two
sides were pressed
together under sufficient pressure to make a seal the capsules would break,
the indicators would
react, and a pink color would be apparent. Potentially this could be done
without the
microcapsules if adequate water could be entrained in an adhesive.
Another approach would be to use encapsulated ink similar to that utilized for
carbonless
forms. These could be printed within the texture of the adhesive closure sytem
opposite the
adhesive and covered with a varnish or other impervious coating, or
potentially between the
adhesive and the bag material. For mechanical closure systems, the
encapsulated ink could be
located within the mechanical interlocking seal.
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Various compositions suitable for constructing the flexible storage bags of
the present
invention include substantially impermeable materials such as polyvinyl
chloride (PVC),
polyvinylidene chloride (PVDC), polyethylene (PE), polypropylene (PP),
aluminum foil, coated
(waxed, etc.) and uncoated paper, coated nonwovens etc., and substantially
permeable materials
5 such as scrims, meshes, wovens, nonwovens, or perforated or porous films,
whether
predominantly two-dimensional in nature or formed into three-dimensional
structures. Such
materials may comprise a single composition or layer or may be a composite
structure of multiple
materials, including a substrate material utilized as a carrier for a
substance.
Once the desired sheet materials are manufactured in any desirable and
suitable manner,
comprising all or part of the materials to be utilized for the bag body, the
bag may be constructed
in any known and suitable fashion such as those known in the art for making
such bags in
commercially available form. Heat or adhesive sealing technologies may be
utilized to join
various components or elements of the bag to themselves or to each other. In
addition, the bag
bodies may be thermoformed, blown, or otherwise molded rather than reliance
upon folding and
bonding techniques to construct the bag bodies from a web or sheet of
material. Two recent U.S.
Patents which are illustrative of the state of the art with regard to flexible
storage bags similar in
overall structure to those depicted in Figures 1 and 2 but of the types
currently available are Nos.
5,554,093, issued September 10, 1996 to Porchia et al., and 5,575,747, issued
November 19, 1996
to Dais et al.
While particular embodiments of the present invention have been illustrated
and
described, it would be obvious to those skilled in the art that various other
changes and
modifications can be made without departing from the spirit and scope of the
invention. It is
therefore intended to cover in the appended claims all such changes and
modifications that are
within the scope of this invention.
