U.S. patent number 3,554,436 [Application Number 04/830,720] was granted by the patent office on 1971-01-12 for recloseable bag member.
Invention is credited to Charles E. Palmer.
United States Patent |
3,554,436 |
Palmer |
January 12, 1971 |
RECLOSEABLE BAG MEMBER
Abstract
A bag member has a tubular body with a sealable inner surface
having a peripheral strip of nonresiliently deformable material
secured thereover. The strip is spaced downwardly from the upper
end of the body to partially block the sealable material and to
expose a peripheral band thereof above the strip at which sealing
can be effected. Because the deformable material is nonadherent to
itself, subjecting the upper end portion of the body to sealing
conditions effects a seal at a location which is substantially
limited to the exposed band of sealable material; because the
deformable material is nonresilient and capable of maintaining a
folded configuration, opposing portions of it may be interengaged
by folding the bag along the strip to provide a closure for the
bag.
Inventors: |
Palmer; Charles E. (Somers,
CT) |
Family
ID: |
25257559 |
Appl.
No.: |
04/830,720 |
Filed: |
June 5, 1969 |
Current U.S.
Class: |
383/204; 383/89;
383/94; 383/107; 383/905 |
Current CPC
Class: |
B65D
33/30 (20130101); Y10S 383/905 (20130101) |
Current International
Class: |
B65D
33/30 (20060101); B65D 33/16 (20060101); B65d
033/30 () |
Field of
Search: |
;229/62,65,66 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bockenek; David M.
Claims
I claim:
1. A bag member comprising a generally tubular body of synthetic
plastic sheet material having a recloseable end portion with a heat
sealable inner surface, and a relatively thin, substantially
continuous strip of nonresiliently deformable material extending
about substantially the entire inner periphery of said end portion
and secured to said end portion at a point spaced from the edge
thereof, said strip partially blocking said sealable surface to
substantially prevent sealing thereat and the edge portion between
said edge and strip providing a peripheral band of sealable surface
at which sealing of the inner surface may be effected, said strip
being dimensioned relative to the length of said body so as to be
located adjacent said end portion with the major portion of said
body being free from said strip, said deformable material being
capable of maintaining a folded configuration and being nonadherent
to itself under the conditions of sealing for said sealable surface
so that subjecting said end portion to the sealing conditions
effects a seal in a location substantially limited to said
peripheral band, and said bag member is recloseable by folding said
bag member along said strip to interengage opposed portions of said
strip.
2. The bag member of claim 1 wherein said sealable surface is
provided by a synthetic thermoplastic polymer.
3. The bag member of claim 1 wherein said body is formed of a
length of heat-sealable synthetic thermoplastic polymeric sheet
material having substantially parallel longitudinal edges, and
wherein said strip is provided by an elongated deformable element
secured transversely of said length of sheet material and
substantially perpendicular to said longitudinal edges thereof,
said body having a longitudinally extending heat-sealed portion
securing said longitudinal edges in overlapping relationship
4. The bag member of claim 3 wherein one end of said deformable
element is secured adjacent and short of the longitudinal edge of
the overlying ply of said sheet material so that said
longitudinally extending heat-sealed portion extends transversely
over a portion of said element adjacent the other end thereof.
5. The bag member of claim 4 wherein said element has an aperture
therein adjacent said one end and wherein said other end thereof
projects beyond the longitudinal edge of the underlying ply of said
sheet material and projects beneath said one end and said aperture,
said sheet material being bonded to said element adjacent said
other end thereof through said aperture to prevent substantially
relative movement of the ends of said element.
6. The bag member of claim 1 wherein said metal foil element is
adhesively secured to said sealable surface by a heat seal along a
line extending longitudinally of said element and spaced from the
edge thereof adjacent the band, so that an unsecured edge portion
of said strip extends beyond said heat seal to reduce any tendency
for the edge thereof to sever said body at a weakened zone produced
directly adjacent said heat seal.
7. The bag member of claim 6 wherein said edge of said element is
relatively sharp and provides a cutting edge to facilitate tearing
and removal of the end portion of said body extending
therebeyond.
8. The bag member of claim 3 wherein the lower end of said tubular
body is sealed by a heat seal extending transversely and generally
perpendicular to the longitudinal edges thereof.
9. The bag member of claim 8 additionally including an article
therewithin, said bag member being sealed within said peripheral
band to provide a recloseable sealed container.
Description
BACKGROUND OF THE INVENTION
Many types of closures and/or design modifications have heretofore
been provided to enable a bag, container or overwrap to be closed
and opened, or to be reclosed after an original seal has been
removed or broken. Such packages are particularly useful when only
a portion of the contents thereof are normally removed, and
especially when the contents are subject to deterioration or
spoilage due to atmospheric conditions after the package has been
opened, e.g. when the package contains baked goods such as bread,
cookies, etc. or when it contains other foodstuffs such as candy
and the like.
Among the various methods which have been used to provide
recloseable packages is the provision of pressure-sensitive
adhesives on one or more portions of the package designed to permit
repeated bonding and release. However, the use of adhesives in this
manner has not been very successful for a number of reasons. As a
fundamental matter, it is difficult to achieve a balance of
properties in an adhesive whereby a desirable level of adhesion is
coupled with relatively facile release characteristics for opening
the package. In addition, there is a tendency for loss of tackiness
to occur rapidly in such adhesives so that after relatively short
periods of use they become relatively ineffectual due either to
frequent opening and closing or to contamination of the adhesive
with dirt particles and the like.
Other attempts to produce closeable packages have relied upon metal
clasps and closures for bags, envelopes etc. made of a variety of
materials including paper and plastics. Such a closure is normally
made of a nonresiliently deformable metal so that it can be bent
upon itself or about a portion of the package to maintain a closed
condition when desired. However, so far as is known the prior art
constructions of this type do not permit convenient and complete
sealing of the package initially, ready opening thereof without
undue damage thereto, and repeated opening and closing of the
package with substantially no loss of effectiveness after extensive
use.
Accordingly, it is an object of the present invention to provide a
bag member which is of a relatively simple construction, which may
be conveniently and completely sealed initially, which may be
readily opened without damage to the main portion the such as would
render the bag unsatisfactory for subsequent use, and which may
thereafter be repeatedly closed and opened without loss of
effectiveness for the closure.
It is also an object of the invention to provide such a bag member
which is initially heat-sealable, i.e., sealed by the application
of heat thereto.
SUMMARY OF THE DISCLOSURE
It has now been found that the foregoing and related objects can be
readily attained in a bag member comprising a generally tubular
body having a reclosable end portion with a sealable inner surface,
and a relatively thin, substantially continuous strip of
nonresiliently deformable material extending about the inner
periphery thereof and secured to said end portion at a point spaced
from the edge thereof. The strip partially blocks the sealable
surface and substantially prevents sealing thereat, and the edge
portion between the edge and strip provides a peripheral band of
sealable surface at which sealing of the inner surface may be
effected. The deformable material is capable of maintaining a
folded configuration and is nonadherent to itself under the
conditions of sealing for the sealable surface. As a result,
subjecting the end portion of the body to such sealing conditions
effects a seal in a location which is substantially limited to the
exposed peripheral band of sealable surface and the bag member is
recloseable by folding the bag member along the strip to
interengage opposed portions thereof.
In a preferred embodiment of the invention, the sealable surface is
heat-sealable, and, more specifically, the sealable surface may be
provided by a synthetic thermoplastic polymer. The body of the bag
member may be formed of a length of heat-sealable synthetic
thermoplastic polymeric sheet material having substantially
parallel longitudinal edges, and the strip of deformable material
may be provided by an elongated deformable element secured
transversely of the length of sheet material and substantially
perpendicular to the longitudinal edges thereof. In such a case,
the body may have a longitudinally extending heat-sealed portion
securing the longitudinal edges of the sheet of packaging material
in overlapping relationship.
In a preferred embodiment of the invention, such a deformable
element is secured with one end adjacent and short of the
longitudinal edge of the overlying ply of such sheet material so
that the longitudinally extending heat-sealed portion previously
referred to extends transversely over a portion of the deformable
element adjacent the other end thereof. In such a case, the first
end of the deformable element secured adjacent the edge of the
overlying ply of the sheet material may be provided with an
aperture and the other end thereof may project beyond the
longitudinal edge of the underlying ply of the sheet material to
extend beneath the first end and the aperture thereadjacent. The
sheet may then be bonded to the deformable element adjacent the
other or projecting end portion through the aperture to prevent
substantial relative movement of the ends of the element.
Preferably, the deformable element comprises a wrought metal foil,
and most desirably the foil element is adhesively secured to the
sealable surfaces by a heat seal along a line extending
longitudinally of the element and spaced from the edge thereof
adjacent the band. In that manner an unsecured portion of the
element will extend beyond the heat seal to reduce any tendency for
the edge thereof to sever the body at a weakened zone produced
directly adjacent the heat seal. Most desirably, the edge of the
element is relatively sharp and provides a cutting edge to
facilitate tearing and removal of the end portion of the body
extending therebeyond. The lower end of the tubular body may be
sealed by a heat seal extending transversely and generally
perpendicular to the longitudinal edges thereof. The bag member may
include an article therewith and may be sealed within the
peripheral band of sealable material to provide a recloseable
sealed bag containing such an article.
In the method of the invention, a recloseable bag member is
produced utilizing a length of packaging sheet material having at
least one pair of substantially parallel edges and at least one
sealable surface. A relatively thin, elongated, nonresiliently
deformable element is secured over the sealable surface
transversely of the length and substantially perpendicular to the
parallel edges of the length to partially block the sealable
surface and expose a band of sealable surface to one side of the
element. Portions of the length along the parallel edges are
contacted and secured together to produce a body of generally
tubular configuration with the deformable element peripherally
disposed therewithin to provide a strip extending about the
periphery thereof. Opposing portions of the band of sealable
surface are contacted under sealing conditions therefor to effect a
seal thereat. The characteristics of the deformable element are as
have been previously indicated so that the seal produced is
substantially limited to the band of sealable surface and the bag
member is reclosable by folding together and thereby interengaging
opposing plies thereof.
The present invention also provides a substantially continuous
method of producing a multiplicity of recloseable sealed bag
members wherein the length of packaging sheet material comprises an
extended length of heat sealable synthetic thermoplastic polymeric
sheet material. In accordance with that embodiment, a multiplicity
of deformable elements are secured to the length of polymeric sheet
material at a multiplicity of points spaced along the length
thereof to provide a multiplicity of units. Each such element
partially blocks the sealable surface and exposes a band thereof on
side of the element. The step of contacting and securing the
parallel edge portions of the length of polymer is effected
substantially continuously for at least a multiplicity of units,
and the step of effecting a seal at opposing portions of the band
of sealable material may serve to simultaneously seal the adjacent
end portions of two adjacent bag members.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a fragmentary plan view of a blank utilized to produce a
bag member embodying the present invention;
FIG. 2 is a perspective view to a slightly enlarged scale of a bag
produced from the blank of FIG. 1 which has been opened by partial
removal of a portion of the body above the foil strip;
FIG. 3 is a perspective view of the bag of FIG. 2 wherein the
portion above the foil strip has been entirely removed and the
piles of the end portion folded together to illustrate the
recloseable feature of the bags of the invention; and
FIG. 4 is a fragmentary sectional view to an enlarged scale of the
reclosed bag along the line 4-4 of FIG. 3.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Turning now in detail to the appended drawing, a recloseable bag
embodying the present invention and illustrated in FIGS. 2 and 3 is
produced simply and economically from the blank shown in FIG. 1.
The blank consists of a rectangular length 10 of transparent
synthetic plastic sheet material and a nonresiliently deformable
metal foil element 12 secured on the underside of the sheet 10 and
adjacent its one edge by a number of heat seals 14 extending along
the length of the foil element 12. The foil element 12 has a hole
18 through it adjacent its end 16 which is spaced inwardly from the
edge 20 of the length 10 to provide spacing therebetween. The end
portion 22 at the opposite end of the element 12 projects beyond
the opposite edge 24 of the length 10 for a purpose which will be
more fully described hereinafter.
The bag illustrated in FIGS. 2 and 3 is produced from the blank by
lapping the edge portions so that the edge 20 is outermost, and the
foil element 12 provides a trip extending about the inner periphery
of the tubular member so produced, i.e., by curving the edges of
the sheet 10 into the page of the drawing. The overlapped edge
portions are heat sealed together within the area of the overlap in
a longitudinal seam 26 to provide a two-ply structure. Since the
end 16 of the foil element 12 terminates short of its associated
edge 20, the plies of plastic sheet material are in contact along
the entire length of sheet material 10, and the seam 26 extends
across the width of the end portion 22 of the element 12 which
projects past the edge 20. Thereafter, the tubular body is closed
at the lower end with a heat seal 28, and the desired contents 30
are placed into the bags produced.
To seal the upper end of the bag the opposing faces A, B of the
length 10 of sheet material are brought into contact and the upper
portion of the bag is subjected to heat sealing conditions. In this
manner, a heat seal 32 is produced in the portion 34 above the foil
element 12, the portion 34 being partly torn away in FIG. 2 for the
purpose of illustration of the manner in which the bag is opened
subsequent to sealing. Subjecting the upper portion of the bag to
heat to effect the seal at 32 also causes the plastic of the sheet
material overlying the hole 18 to adhere to the end portion 22 of
the element 12 is prevented from hinging away from the end portion
adjacent the edge 16 thereof sa so as to avoid tearing of the
plastic sheet material within the area of overlap of the edges 20,
24.
Turning now in greater detail to FIGS. 3 and 4 therein illustrated
is the manner in which the bag is reclosed after the portion 34 has
been torn away to open the bag. Thus, the opposite faces A, B of
the bag are brought together to position opposite portions of the
foil element 12 in face-to-face contact, and the element 12 is then
folded longitudinally at a point which is preferably approximately
midway between its edges. Due to the nonresilient deformability of
the foil element 12 and its ability to maintain a folded
configuration, the resulting interengagement of the opposing
portions of the element 12 maintains the bag in the closed position
shown in FIGS. 3 and 4.
Outstanding features of the novel bag members disclosed herein are
the convenience and effectiveness of the initial sealing thereof
and the ease with which they may be opened initially, and
thereafter closed and opened repeatedly during subsequent use.
These advantages result in part from the novel placement of the
element or strip of nonresiliently deformable material in a
position to partially block the sealable surface on the inside of
the sheet material, thus ensuring that it can be opened without
significant detriment to the portion of the body below the
nonresiliently deformable strip, and yet to expose a portion of the
sealable surface thereabove for initial sealing. Securing the
deformable material on the outside surfaces of the article in a
manner contrary to the concept of the present invention
necessitates very careful control and placement of equipment during
the sealing step to avoid the creating of a seal under or between
the plies of deformable material which would render the package
virtually impossible to open without considerable inconvenience and
without rendering it unsatisfactory for further use. Although it
may be possible to avoid sealing at undesired locations by
confining the effects of the sealing conditions to an area
adequately spaced from the strip of nonresiliently deformable
material, achieving the necessary level of control would be quite
difficult on an economically feasible basis.
The method of effecting the seal to close the bag initially (and of
effecting other seals during the fabrication thereof) may vary
widely and will depend primarily upon the characteristics of the
sealable material involved. Although other techniques may be
feasible, the most effective and convenient manner of producing the
seals will usually be by use of an elevated temperature technique
employing materials which are heat sealable, i.e., rendered
adhesive or tacky by subjecting them to heat. Many different types
of heat-sealing apparatus may be used, such as the conventional
heated jaws or rollers, and the heat source may involve infrared,
dielectric, ultrasonic, or impulse heating effects.
The sealable surface or material may be provided by the inherent
thermoplastic nature of the packaging sheet material of which the
entire body of the bag member is constructed, or a heat activatable
coating may be used on the inner surface, such as by laminating a
film of greater heat-sealing characteristics to a film having less
effective heat-sealing characteristics. More particularly, the
packaging material may be sheet material of a synthetic
thermoplastic polymeric resin having inherent sealing
characteristics such as the olefin and vinyl homopolymers and
copolymers, the vinyl chloride/vinylidene chloride copolymers, the
ethylene/vinyl acetate copolymers, etc.; in many instances
laminated combinations of or with such polymers are particularly
preferred. Both (or all) components of such a laminate may have
sealing characteristics, or one of the components may provide other
properties which are desired, such as a nonsticking surface or
advantageous gas and liquid permeation characteristics, certain of
which may be obtainable with layers of paper, cellophane,
polyesters, and the like. The packaging material may be a normally
nonsealing material such as paper treated with a sealable
composition, and such treatment may involve coating the paper with
a heat-activatable adhesive or by dispersing a suitable polymer in
the fiber slurry during its manufacture; the inner surface of a
sheet material component may be entirely coated with the
heat-sealable material or coated in only limited areas thereof.
The appropriate thickness of the packaging material will depend
primarily upon the intended use of the bag member and is readily
determinable by those skilled in the art. Polymeric sheet material
will normally range from about 0.5 to 5.0, and will preferably be
about 1.0 to 3.0 mils in thickness. In some instances the packaging
material may be as much as 30 or more mils thick, but the design of
an economically feasible process employing such heavy gauge
materials will usually entail more complicated equipment and
procedures, and the gauge of deformable material necessary to
maintain such a package closed may be prohibitive.
As has been mentioned, the material most appropriate for use as the
deformable material is foil of a relatively ductile metal such as
aluminum. It may be possible to substitute other nonresiliently
deformable structures such as can be produced with a wire framework
or skeleton (which may or may not be attached to or imbedded within
a matrix such as paper), but from the standpoint of economics and
convenience of manufacture the metal foils will generally be
preferable. Virtually any configuration may be employed for the
deformable element which will provide a substantially continuous
strip or loop within the article when it is formed to provide the
tubular body. Accordingly, the length of the material should be at
least equal to the peripheral dimension of the tubular body, and
preferably it will be somewhat longer. If the deformable element
does not completely encircle the article gaps will be present to
provide a course along which the tear for opening the package can
proceed into the main part of the body, thus damaging it and
rendering it less satisfactory for subsequent use. Notwithstanding
this, discontinuities in the strip at the sides of the bag are
somewhat advantageous because the sharp corners which otherwise
result from the return bend of deformable material thereat are
thereby eliminated so as to reduce the tendency for the packaging
material to be cut by such sharp corners. As has been pointed out
with reference to the drawings, the deformable element is
preferably longer than the peripheral or circumferential dimension
of the bag to provide a bridge which avoids a gap in the
overlapping area along which tearing could result. However, in such
a structure it is important that the end of the strip which extends
beyond the edge of the sheet of material be secured against
hinging, such as by bonding it through a hole or at cut out
portions along the edges of the strip.
As regards the transverse or width dimension of the strip, it need
only be wide enough to allow facile folding longitudinally thereof
to provide adequate interengagement, and the same criterion is
applicable to determine an appropriate thickness for the strip or
deformable element. It should be appreciated that the use of metal
foil is of particular advantage because the foil element also
provides a cutting edge adjacent the upper end of the article for
initial tearing away from the end portion above the foil element to
effect opening, either by providing a sharp straight edge or one
which is serrated to promote cutting of the packaging material. The
positioning of the strip on the inside of the bag is also important
in this respect since a strip located on the exterior surface would
allow the material of the bag to be torn between the plies thereof
and would therefore render it ineffective as a cutting edge.
The packaging material will normally be employed initially in the
form of individual rectangular lengths of sheet material or as a
substantially continuous length having parallel longitudinal en
edges. When the packaging material is provided as a substantially
continuous length to enable to the production of a multiplicity of
bags on a continuous or semicontinuous basis, the elements of
deformable material are secured thereto at a multiplicity of points
spaced along the length thereof and substantially perpendicular to
the longitudinal or parallel edges thereof. Thereafter, the length
of packaging material is formed into a generally cylindrical
configuration, such as by rolling or folding it about a suitable
mandrel, and the longitudinal edges thereof are heat sealed
together continuously along the length of material as it passes
over the mandrel. As the body thus formed passes from the mandrel,
a second sealing mechanism may pinch or otherwise secure opposite
sides together, simultaneously forming a lower end seal for one bag
and an upper end seal for the preceeding one. The mandrel in such a
method may suitably be hollow for use in filling the packages with
the desired contents prior to sealing of the end portions.
The manner in which the deformable elements are secured to the
packaging material may vary considerably and will depend largely
upon the specific materials involved; advantageously, the sealable
surface itself fun furnishes the necessary bonding characteristics.
For most satisfactory results, it is usually necessary to pretreat
the foil element such as by coating it to render it more readily or
more strongly adherent, and the coating composition will depend
upon the particular sealable surface that is involve. For example,
aluminum foil coated with a polyolefin composition readily adheres
to a polyethylene sheet under heat-sealing condition, and this
combination constitutes a particularly advantageous embodiment of
the invention.
When the foil element is heat sealed to the packaging material, the
locations of the seals can be quite significant. In most
thermoplastics, heat sealing generally has the effect of weakening
the plastic in a zone directly adjacent the heat-sealed area. This
is advantageous from the standpoint of opening the bag, when
desired, but it may be disadvantageous if it causes the bag to
rupture or open prematurely. Accordingly, if the heat seal on the
deformable element is directly adjacent the edge thereof, there
will be a greater tendency for the strip to sever the packaging
material prematurely since the edge and the weakened zone coincide.
Spacing the heat seal inwardly from the upper edge of the foil
element greatly reduces this tendency and yet permits facile
opening of the bag since the weakened zone is still present but it
is spaced from the edge of the strip. The cooperative effects of
the tearing edge provided by the strip and of the weakened zone
resulting from the heat seal results in a bag which is readily
opened when desired and yet securely sealed until time. Although
not illustrated, appropriately located nicks or cuts can be
provided to initiate the tear for even more facile opening of the
bag.
Thus, it can be seen that the present invention provides a bag
member which is of a relatively simple construction, which may be
conveniently and completely sealed initially, which may be readily
opened without such damage as would render the bag unsatisfactory
for subsequent use, and which may thereafter be closed and opened
repeatedly without loss of closing effectiveness. The bag member
may be produced economically and rapidly in a simple but highly
effective manner adapted to continuous or semicontinuous operation
on automatic filling apparatus.
* * * * *