U.S. patent application number 11/660474 was filed with the patent office on 2012-02-16 for high-integrity closure.
Invention is credited to Michael E. Schreiter, Paul Tilman, Judith A. Yaeger.
Application Number | 20120036684 11/660474 |
Document ID | / |
Family ID | 45563694 |
Filed Date | 2012-02-16 |
United States Patent
Application |
20120036684 |
Kind Code |
A1 |
Tilman; Paul ; et
al. |
February 16, 2012 |
High-integrity closure
Abstract
The present invention provides a resealable closure structure
(999) which provides at least one region of continuous gas-sealing
abutment (900) upon engaging the interengaging members (988, 978)
of the closure. The closure provides a region of gas sealing
abutment by one or more of. (i) mechanical abutment of closure
features (1010, 1013) and associated therewith a caulking
composition (990) and/or a sealing material (945); and (ii)
defining a void region (1030) by proximity of closure features when
interengaging members of the closure are engaged (1020, 1021) which
has gas-sealingly infiltrated thereinto a caulking composition
(945).
Inventors: |
Tilman; Paul; (Sherwood,
WI) ; Schreiter; Michael E.; (Appleton, WI) ;
Yaeger; Judith A.; (Appleton, WI) |
Family ID: |
45563694 |
Appl. No.: |
11/660474 |
Filed: |
August 19, 2005 |
PCT Filed: |
August 19, 2005 |
PCT NO: |
PCT/US05/29632 |
371 Date: |
October 1, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60602685 |
Aug 19, 2004 |
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60609920 |
Sep 15, 2004 |
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Current U.S.
Class: |
24/399 |
Current CPC
Class: |
A44B 19/16 20130101;
Y10T 24/2532 20150115; B65D 33/2541 20130101 |
Class at
Publication: |
24/399 |
International
Class: |
A44B 19/16 20060101
A44B019/16 |
Claims
1. A resealable closure comprising: (i) at least one pair of
opposed interengaging members, each said member affixed to an
opposed portion of the closure and disposed to engage when said
opposed portions of the closure are brought together with an
applied engaging force; and (ii) optionally, a sealing material
comprising one or more portions of said closure; and (iii)
optionally, disposed on the closure to bring said opposing closure
portions together with an engaging force when operated from a first
position to a second position, a member selected from the group
consisting of a slider and a closing clip, wherein the closure is
further characterized in that engaging said interengaging members
creates at least one region of continuous gas-sealing abutment
between said pair of opposed closure portions.
2. The resealable closure of claim 1 wherein said region of
gas-sealing abutment comprises at least one pair of opposing
features, each said feature disposed on one said opposed closure
portion to abut the other said feature when said interengaging
members are engaged, and a caulking compound disposed on the
closure to gas-sealingly infiltrate at least one void region
defined by said abutted features when said interengaging members
are engaged.
3. The resealable closure of claim 1 wherein the closure contains
at least one weld, said weld comprising a sealing material.
4. The resealable closure of claim 1 wherein said region of
gas-sealing abutment comprises at least one pair of opposing
features, each said feature disposed on one said opposed closure
portion to abut the other said feature when said interengaging
members are engaged, at least one said feature comprising a sealing
material.
5. The closure of claim 4 further comprising a caulking compound
disposed on the closure to gas-sealingly infiltrate at least one
void defined by abutting said pair of opposing features when said
interengaging members are engaged.
6. The closure of claim 4 wherein said sealing material is selected
from the group consisting of polyolefins having a density of less
than about 0.925 g/cm3 as measured in accordance with ASTM D1505-03
(Nov. 1, 2003), low density polyethylene and polyolefin containing
an amount of vinyl acetate to yield a blend having a low melt index
of less than about 7, as measured in accordance with ASTM
D-1238-04c.
7. The resealable closure of claim 2 having at least one pair of
interengaging members comprising: (i) a first interengaging member
comprising: (1) at least one profile portion affixed to the
proximal face of a first opposed portion of the closure, said
profile portion comprising: (a) a first locking member comprising:
(i) a first stem member joined to the proximal face of said first
opposing portion of the closure; and (ii) a first head member
affixed to the free end of said first stem member; (b) a first post
affixed on said first opposed portion proximal face substantially
parallel and proximal to said first stem member, said first post
disposed to define a first channel with said first head member, and
wherein said first stem member, first head member, and said first
post together are configured and disposed to define a first void
region; (c) optionally a third post affixed to said first opposed
proximal face substantially parallel to said stem on the side of
the stem distal from said first post; (d) optionally a fourth post
affixed to said opposed proximal face substantially parallel and
proximal to said first post on the side of said first post distal
from said first head member; (B) a second interengaging member
comprising: (1) at least one second locking member joined to a
proximal face of a second opposed portion of the closure, said
second locking member comprising: (a) a second stem member joined
to said proximal face of a second opposed portion of the closure;
(b) a second head member affixed to the free end of said second
stem member; (2) optionally a second post affixed to said second
opposed portion proximal face substantially parallel to said second
locking member, disposed to define a second channel with said
second head member, wherein said second stem member, said second
head member and said second post are configured and disposed to
define a second void region; and (3) optionally, when a second post
is present, a fifth post mounted substantially parallel and
proximal to said second post on the side of said second post distal
from said second locking member, wherein the closure is further
characterized in that each of said first and second interengaging
members are disposed such that when said proximal faces are brought
together with an applied engaging force, the head of said second
locking member is received into the channel defined by said first
stem and first head member, and said second locking member is
engaged within the void region defined by said first engaging
member.
8. The resealable closure of claim 2 wherein each said
interengaging member comprises: (a) at least two locking members,
each said locking member comprising: (3) a stem affixed to a
proximal face of an opposed portion of the closure; (4) a head
member affixed to the free end of said stem; and (c) optionally,
one or more posts, wherein, when the interengaging members are
engaged the locking members affixed to each said opposed closure
portion are interdigitated.
9. The resealable closure of claim 8 wherein said head members are
asymmetrically attached to said stems, and the locking members
comprising one of said interengaging members are rotationally
symmetrical with the locking members of the other of said
interengaging members.
10. The resealable closure of claim 8 wherein said head members are
symmetrically attached to said stems, and, when present, said posts
are configured and disposed to form, together with an adjacent
locking member, a void which has a cross-sectional shape that is
complimentary to a locking member affixed to said opposed
interengaging member which is interdigitated between said post and
adjacent member upon engagement of said interengaging members.
11. The resealable closure of claim 8 wherein a sealing material is
coextruded to form at least a portion of at least one said head
member, wherein said portion of sealing material disposed to
sealingly abut a portion of an interengaging member with which it
is engaged.
12. The resealable closure of claim 7 comprising at least two pairs
of interengaging members mounted substantially parallel on said
opposing closure portions.
13. The resealable closure of claim 7 further comprising a crush
seal area at the ends of said closure joining together said opposed
closure portions, wherein the crush seal area further comprises a
sealing material.
14. The resealable closure of claim 7, wherein interengaging
members comprises a high melt index polyolefin and said regions of
sealing material comprises a low melt index polyolefin.
15. The resealable closure of claim 7 wherein said caulking
composition comprises a member selected from the group consisting
of a silicone oil, a silicone grease, a soy polymer, and a soy
adhesive.
16. The resealable closure of claim 8 wherein one said interlocking
profile contains a distal post mounted on said opposed portion
proximal face substantially parallel to said stem on the side of
the stem distal to said first post forming a well distal from said
channel, the bottom of which is abutted by the post of the opposing
profile when said interengaging members are engaged.
17. The resealable closure of claim 7 which includes said fourth
and fifth posts, wherein said fourth and first posts form a well
having therebetween a region of the opposed closure portion
comprising a well bottom, and wherein the free end of said fifth
post abuts said well bottom region when said interengaging members
are engaged.
18. The resealable closure of claim 17 wherein at least one of said
well bottom and the free end of said fifth post comprises a member
of the group selected from: (a) a sealing material; (b) a caulking
composition; (c) an adhesive; (d) a soy polymer; (e) a silicone
grease.
19. The resealable closure of claim 17 wherein each of said well
bottom and the free end of said fifth post comprise one part of a
two part reactive composition such that when said interengaging
members are engaged each said part of the two part reactive
composition is admixed, providing a reaction product.
20. A package comprising the closure of claim 2.
21. The closure of claim 7 wherein said caulking composition is
rated for at least incidental contact to food items.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 60/590,858 filed on Jul. 23, 2004, 60/602,685
filed on Aug. 19, 2004, 60/609,920 filed on Sep. 15, 2004 and U.S.
Application Ser. No. 11/186,131 filed on Jul. 20, 2005, the
disclosure of each of which is fully incorporated by reference
herein.
FIELD OF THE INVENTION
[0002] The present invention relates to a closure comprising at
least two interengaging profiles which optionally includes a
sealing material and which optionally has associated therewith a
caulking composition. The present invention also relates to a
storage device having a closure which defines the opening of the
storage device and a method of manufacturing the same.
BACKGROUND OF THE INVENTION
[0003] Flexible, sealable storage devices, such as Consumer Storage
Bags are commonly used to store items such as, but not limited to,
food. These packages typically have a bag body made from a thin,
flexible plastic material and include an opening defined by a
resealable closure. Typically the resealable closure includes at
least one pair of profiles which interlock to close the package
opening. In general the profiles are designed with undercut
portions which interlock when the profiles are pressed together,
and disengage when the profiles are pried apart. However, in
general, in a resealable closure engagement of the structures does
not provide continuous sealing contact between structures on
opposite portions of the closure, leaving gaps along the region
where the closure profiles are engaged. Consequently, closures
containing gaps between the interlocking portions permit exchange
of gases and vapors between the interior of the package and the
ambient environment in which the packaged materials are stored.
Moreover, during manufacture of reclosable devices, frequently
seals at the ends of the reclosable device distort the engaging
portions of the closure which can also provide an unsealed region
in the closure.
[0004] As a consequence, when a bag have a resealable closure is
subjected to a pressure differential, for example, when it is
evacuated or when there is a partial pressure differential of a
particular gas between the inside and outside of the bag, gas
and/or vapor exchange readily occurs across the resealable closure,
entering or leaving the sealed package through the closure. Thus,
gases, for example, air may penetrate into a sealed bag, or for
example water vapor may leak from a sealed bag. This is especially
a problem when the interior of the bag is at a different pressure
than the ambient air, for example, when the bag is under a vacuum,
or when the bag contains a gas at a higher or lower partial
pressure than the gas or vapor than is present in the ambient, for
example, when a package containing a high moisture content material
is stored in a refrigerated environment where the there is a low
partial pressure of water vapor. Developments have been undertaken
in the design of bag bodies to address such gas and vapor exchange
through the walls of the package, for example, forming the storage
device body from materials which comprise multiple layers of
material, for example, the bags described in U.S. Pat. No.
4,756,422, which is incorporated herein by reference.
[0005] Exchange of gas and vapor in a stored food item, for
example, oxygen and water vapor, can lead to despoliation of a
foodstuff contained in the storage device. As mentioned above,
excessive air within a storage device containing food is not
desirable as the air reacts with the food and will cause
spoliation. This problem is exacerbated when storage bags are
placed in a below freezing environment, typically in a freezer,
imparting "freezer burn" to the stored food items. Freezer burn
occurs when moisture is drawn from the food item and forms ice,
typically on the food item. Freezer burn is reduced when entrapped
air is substantially eliminated from the storage device, for
example, by contouring of the bag wall of the storage device around
the food item, providing for a reduction in the amount of moisture
drawn out of the food item. However, expulsion of residual air
prior to sealing the storage device is rendered nugatory when
exchange of gas and vapor is possible between the ambient
environment and the interior of the sealed storage device across a
resealable closure. This problem has been solved in some vacuum
systems by providing a package which does not utilize a resealable
closure, but instead utilizes a heat sealing mechanism to
permanently seal the storage device after evacuation. Such systems
however, have the disadvantage that once opened the storage bag is
useless for further storage. Attempts to address this problem in
packages having a resealable closure include the provision of an
adhesive seal within the opening of the package inboard of the
reclosable structure. However, such adhesive seals are generally
reserved for commercially prepared packages in which a consumable
commodity is placed in the bag prior to making the seal. In such
packages, the adhesive seal is broken by the end user prior to
consumption and is not reusable. Accordingly, such adhesive seals
are not suitable for applications involving resealable storage
packages for use in providing a reusable bag which is initially
filled by an end user.
[0006] Heretofore, resealable closures have utilized one or more
pairs of interlocking profiles to close the opening of the storage
device. These closures comprise a pair of opposed flanges on either
side of the package opening, each of which contains at least one
stem projecting therefrom having a profile attached to the free end
of the stem which contains an undercut feature disposed to
interlock with an undercut feature on a similar profile affixed to
the free end of a stem projecting from the opposite flange.
Accordingly, previous closures employ interlocking parts configured
to resist separation of the interlocked parts, but which are not
designed to insure that at least some portion of each profile
maintains sealing contact with a portion of the opposite profile to
form a high-integrity seal between the two halves of the closure.
Accordingly, the gaps between the engaged profiles of these prior
art closures provide a pathway for ready exchange of gas and vapors
between the interior of the sealed package and the ambient
environment in which the package is placed.
[0007] Thus, there is need for a resealable closure which provides
for a high-integrity, resealable seal in at least some portion of
the closure between a feature on each of the opposed flanges of the
closure. Accordingly, there is a need for a flexible, resealable
storage device wherein the sealing structure has a resistance to
gas and vapor (fluid) permeability across the sealing device.
Moreover, there is a need for a closure providing reduced
permeability to oxygen, atmosphere intrusion or transmission,
bacteria, molds and/or other sources of contamination when placed
in an environment where there is a pressure differential across the
closure.
SUMMARY OF THE INVENTION
[0008] These needs, and others, are met by the present invention
which in one embodiment provides a resealable closure comprising at
least one pair of interengaging members affixed to opposed portions
of the closure, characterized in that engaging said interengaging
members creates at least one region of gas-sealing abutment between
said pair of opposed closure portions. In some embodiments the
resealable closure comprises more than one pair of interengaging
members. In some embodiments engaging said interengaging members
creates more than one region of gas-sealing abutment between said
opposed closure portions.
[0009] In some embodiments the present invention provides a
resealable closure comprising: (i) at least one set of
interengaging members disposed on opposing portions of the closure
such that bringing together said opposing portions with an applied
engaging force engages said interengaging members; (ii) optionally
a member selected from the group consisting of a slider and a
closing clip disposed on the closure to bring said opposing closure
portions together with an engaging force when operated from a first
position to a second position; (iii) optionally a sealing material
comprising one or more portions of the closure; and (iv) a caulking
composition provided on the closure in void-sealing disposition to
at least one pair of opposing features, each said feature disposed
on one of said opposed closure portion to abut the other said
feature when said interengaging members are engaged, the caulking
composition characterized in that engaging said interengaging
members abuts said at least one pair of opposed closure features
and gas-sealingly infiltrates said caulking composition into at
least one void defined by said abutted opposing closure features,
thereby providing a region of gas-sealing abutment between said
void-defining abutting opposed features.
[0010] In some embodiments the closure is formed from a material
comprising a high melt index (MI) polyolefin. In some embodiments
the high MI polyolefin has a density of at least about 0.925 g/cm3
as measured in accordance with ASTM D1505-03 (Nov. 1, 2003). In
some embodiments, welded portions of the closure comprise a sealing
material.
[0011] In some embodiments, a region of gas-sealing abutment is
provided by providing a sealing material disposed in at least one
abutting portion of at least one of said opposed pair of closure
portions. In some embodiments, a region of the closure comprising a
sealing material is formed by co-extruding a high melt index
polymer and the sealing material to form the closure.
[0012] In some embodiments the sealing material comprises a
material selected from low melt index polymers, for example, a low
density polyolefin, for example, polyolefin having a density of
less than about 0.925 g/cm3 as measured in accordance with ASTM
D1505-03 (Nov. 1, 2003), low density polyethylene and polyolefins
containing an amount of vinyl acetate to yield a blend having a low
melt index, as measured in accordance with ASTM D-1238-04c.
[0013] In some embodiments a region of gas-sealing abutment is
provided by a caulking composition disposed to infiltrate at least
one void defined by abutting portions of the two opposed closure
portions. In some embodiments the caulking composition comprises a
bead of material associated with the interengaging portions of the
closure. In some embodiments the caulking composition is disposed
proximal to at least one crush weld area of the closure.
[0014] In some embodiments the caulking composition comprises a
mixture suitable for at least incidental contact to food items. In
some embodiments the caulking composition is constituted to
maintain caulking properties without denaturing or separating over
a temperature range of from about -10.degree. F. to about
+160.degree. F. In some embodiments the caulking composition is
selected to change state from a free-flowing liquid to a viscous
solid as the temperature decreases, for example, over a temperature
range from about -40.degree. F. to about 140.degree. F.
[0015] In one embodiment the caulking composition comprises liquid
silicone and fumed silica, in proportions to provide a grease with
a grease consistency number of approximately 2.0, as characterized
by National Lubricating Grease Institute (NGLI) standards. In one
embodiment the caulking composition comprises a soy adhesive, for
example, Pro-cote.RTM. soy polymer available from DuPont.TM. (E. I.
du Pont de Nemours and Company). In another embodiment, the
caulking composition comprises soy oils, for example, those
available from Cargill.TM. Industrial Oils & Lubricants. In one
embodiment the caulking composition comprises two reactive
constituents, each residing on a different portion of the closure,
such that when the interengaging profiles of the closure are
engaged the two constituents are admixed, providing a reaction
product which infiltrates at least one void defined by the
interengaging closure profiles.
[0016] In some embodiments the inventive resealable closure defines
an opening into the interior space of a storage package. In some
embodiments said opposed portions of the closure comprise opposed
flanges and each of said interengaging members of the closure is
affixed to a proximal face of one of each of said flanges. In some
embodiments the opposed portions of the closure comprise plastic
sheets forming opposed walls of a flexible package proximal to a
package opening and said first interengaging and profile members of
the closure are each affixed directly to one of said opposed
walls.
[0017] In some embodiments the interengaging members of the closure
comprises a single locking member on one of the opposing portions
of the closure which is disposed to engage a profile on the other
opposing portion of the closure when the two opposing portions of
the closure are brought together with an engaging force. In some
embodiments the interengaging members comprise a pair of
interlocking profiles each mounted on one of the opposing portions
of the closure and disposed to interengage when the opposing
portions are brought together with an engaging force. In some
embodiments each of the interengaging members comprises multiple
pairs of locking members which are configured and disposed on
opposing portions of the closure to define a series of voids such
that the locking members affixed to one opposed portion of the
closure interdigitate with those affixed to the other opposed
portion of the closure when the opposing portions are brought
together with an engaging force.
[0018] In some embodiments at least one pair of interengaging
members of the closure comprises:
[0019] (A) a first interengaging member comprising: [0020] (1) at
least one profile portion affixed to the proximal face of a first
opposed portion of the closure, said profile portion comprising:
[0021] (a) a first locking member comprising: [0022] (i) a first
stem member joined to the proximal face of said first opposing
portion of the closure; and [0023] (ii) a first head member affixed
to the free end of said first stem member; [0024] (b) a first post
affixed to said first opposed portion proximal face substantially
parallel and proximal to said first stem member, said first post
disposed to define a first channel with said first head member, and
wherein said first stem member, first head member, and said first
post together are configured and disposed to define a first void
region; [0025] (c) optionally a third post affixed to said first
opposed proximal face substantially parallel to said stem on the
side of the stem distal from said first post; [0026] (d) optionally
a fourth post affixed to said opposed proximal face substantially
parallel and proximal to said first post on the side of said first
post distal from said first head member;
[0027] (B) a second interengaging member comprising: [0028] (1) at
least one second locking member joined to a proximal face of a
second opposed portion of the closure, said second locking member
comprising: [0029] (a) a second stem member joined to said proximal
face of a second opposed portion of the closure; [0030] (b) a
second head member affixed to the free end of said second stem
member; [0031] (2) optionally a second post affixed to said second
opposed portion proximal face substantially parallel to said second
locking member, disposed to define a second channel with said
second head member, wherein said second stem member, said second
head member and said second post are configured and disposed to
define a second void region; and [0032] (3) optionally, when a
second post is present, a fifth post mounted substantially parallel
and proximal to said second post on the side of said second post
distal from said second locking member, wherein the closure is
further characterized in that each of said first and second
interengaging members are disposed such that when the proximal
faces of the opposed closure portions are brought together with an
applied engaging force, the head of said second locking member is
received into the channel defined by said first stem and first head
member, and said second locking member is engaged within the void
region defined by said first engaging member.
[0033] In some embodiments, the head members have a cross-sectional
shape which is asymmetric relative to the centerline of their
respective stem members. In some embodiments, the head members have
a cross-sectional shape which is symmetric relative to the
centerline of their respective stem members.
[0034] In some embodiments, each opposing closure portion contains
a series of locking members defining a series of channels and void
spaces. In some embodiments the interengaging members of the
resealable closure comprise:
[0035] (a) at least two locking members, each said locking member
comprising: [0036] (1) a stem affixed to a proximal face of an
opposed portion of the closure; [0037] (2) a head member affixed to
the free end of said stem; and
[0038] (b) optionally, one or more posts,
wherein, when the interengaging members are engaged the locking
members affixed to each said opposed closure portion are
interdigitated. In some embodiments the series of locking members
have asymmetrically mounted head members and the locking members
comprising one of said interengaging members are rotationally
symmetrical with the locking members of the other of said
interengaging members. In some embodiments, the head members are
symmetrically attached to said stems, and, when present, said posts
are configured and disposed to form, together with an adjacent
locking member, a void which has a cross-sectional shape that is
complimentary to a locking member comprising said opposed
interengaging member which is interdigitated between said post and
adjacent member upon engagement of said interengaging members.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] A full understanding of the invention can be gained from the
following description of the preferred embodiments when read in
conjunction with the accompanying drawings in which:
[0040] FIG. 1 is a cross-sectional side view of a resealable
closure of the invention utilizing an interengaging member on each
flange, each of which defines also a profile.
[0041] FIG. 2 is a cross-sectional side view of a closure having a
single set of interengaging members wherein the interengaging
members define also a profile on each flange and wherein each
profile has associated therewith an additional post.
[0042] FIG. 3 is a cross-sectional side view of a closure having a
single set of interengaging members wherein the interengaging
members define also a profile on each flange and wherein one
profile has associated therewith an additional post distal from the
engaging face of the profile.
[0043] FIG. 4 is a plan view of a profile comprising one half of a
closure illustrating regional distribution of sealing material and
regional application of caulking composition across the
profile.
[0044] FIG. 5 is a cross-sectional side view of the closure of FIG.
3 which contains additional an adhesive caulking composition.
[0045] FIG. 6 is a cross-sectional side view of a closure
illustrating the distribution of caulking composition external to
the interengaging portions of the closure.
[0046] FIG. 7 is a cross-sectional side view of a closure having
symmetrical interengaging members.
[0047] FIG. 8 is a cross-sectional side view of a closure which
includes a sealing material coextruded at the tips of the
interengaging members.
[0048] FIG. 9A is a cross-sectional side view of a closure having a
pair of interengaging members, and distributed therebetween, a
caulking composition which is not infused into the voids in the
interengaged closure members.
[0049] FIG. 9B is a cross-sectional side view of a closure having a
pair of interengaging members, and distributed therebetween, a
caulking composition which is infused into the voids between the
interengaged closure members.
[0050] FIG. 10 is a cross-sectional side view of a closure having a
pair of interengaging members and additional post members
configured to abut each of the interengaging members on their
exterior edge.
[0051] The present invention is now discussed in more detail
referring to the drawings that accompany the present application.
In the accompanying drawings, like and/or corresponding elements
are referred to by like reference numbers.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The Closure
[0052] With reference to FIG. 1, the closure of the present
invention comprises a pair of opposed portions (101, 121) having
mounted on each proximal face thereof (110, 130) at least one of a
pair of interengaging members (100, 120) disposed on the proximal
faces such that when the opposed portions of the closure are
brought together with an engaging force the interengaging members
are engaged. The closure is further characterized in that when the
interengaging members are engaged, at least one region of
gas-sealing abutment is created between the opposed portions of the
closure.
[0053] In closures of the present invention, gas-sealing abutment
comprises one or more of: (i) mechanical contact (abutment) between
one or more features or regions of each of the opposed closure
portions in conjunction with: (a) a caulking composition disposed
to gas-sealingly infiltrate any voids defined by the abutting
features; and/or (b) one or more of said contacting features on at
least one of the opposed closure portions comprising a sealing
material (discussed herein below in greater detail); and (ii)
gas-sealing infiltration of a caulking composition into one or more
void spaces defined by one or more features on each of the opposed
closure portions being positioned proximal when the interengaging
members of the closure are engaged (described herein below in
greater detail). Accordingly, gas-sealing abutment can comprise a
region of mechanical contact between features affixed to each of
the two opposed portions of the closure, or a void region defined
by a feature on each of the opposed portions of the closure that
are positioned proximal upon engagement of the interengaging
members and into which a caulking composition is gas-sealingly
infiltrated.
[0054] An example of gas-sealing abutment arising from mechanical
contact is illustrated, for example, in FIG. 9A wherein a bead of
sealing material (945) is placed into abutment with locking member
(905) when the interengaging members are engaged. An example of
void defined upon engagement of the interengaging members by
features on each of the opposing portions of the closure being
placed proximal with gas-sealing infiltration of a caulking
composition thereinto is illustrated, for example, in FIG. 2, by
the shaded area about the engaged interengaging members located
between post (226) and post (206) which has been infiltrated with a
caulking compound (shaded portion designated generally 250), and in
FIG. 9B, the void region traversing the length of the closure
between opposing closure portions (901, 921) in which caulking
compound (900) is infiltrated. With reference to FIG. 10, for
example, mechanical contact is illustrated by abutment in region
(1011) of post (1001) with post (1010), and in region (1013) of
post (1002) with post (1012), which occurs when interengaging
member pairs (1020, 1021) are engaged.
[0055] Mechanical abutment and void-defining proximity can be
established upon engagement of the interengaging members using
either features associated on or within the interengaging members,
for example, as shown and discussed above in FIGS. 9 and 2, or
between features affixed to each of the opposed closure portions
remote from the interengaging members of the closure, for example,
as shown in FIG. 6, wherein abutment occurs between posts (606,
626) abutting closure bead features (646, 645) respectively,
outside of the portion of the closure comprising the interengaging
members, that is, outside of region (650). In further example, as
illustrated in FIG. 10 by void region (1030) which traverses the
closure, and which is defined by the proximity posts (1001, 1010,
1002, and 1012) upon engagement of the pairs of interengaging
members.
[0056] In some embodiments the closure will comprise more than one
set of interengaging members, for example, as illustrated in FIGS.
9A and 9B and in FIG. 10 which has two pairs of interengaging
members residing in parallel (1020 and 1021, respectively). When
multiple pairs of interengaging members are present, gas-sealing
abutment can comprise a caulking composition infiltrated into the
void region defined between the sets of engaged interengaging
members of the closure, for example, region (1030).
[0057] In addition to the interengaging members and the structures
forming the region of gas-sealing abutment between opposed closure
portions discussed above, the closures of the present invention may
comprise other features, for example, gripping tabs (70), as
illustrated in FIG. 1, and (868, 869), as illustrated in FIG. 8.
Optionally the closure may include also a closing clip such as are
known in the art to engage the interengaging members or a slider,
such as are known in the art to facilitate opening and reclosing
the closure.
[0058] The closure of the present invention will be most useful
when employed to close the opening of a flexible package, for
example, a plastic bag. Accordingly, the opposing portions of the
closure may comprise a pair of flanges for example, as illustrated
in FIG. 1, flanges (101, 121), and as illustrated in FIG. 8,
flanges (850, 852), which will be used to affix the closure to a
bag opening. Alternatively, the closure of the present invention
may comprise portions of the opposing walls of a bag into which the
features of the closure have been directly molded.
[0059] As will be appreciated, when the opposed portions of the
closure comprise a flange, in some embodiments the closure features
may be disposed at one edge of the flange, also termed herein
sometimes for convenience as a two-flange closure. In some
embodiments comprising a flange the closure features may be
disposed centrally on the flanges, also termed herein sometimes for
convenience as a four-flange closure.
[0060] In general, whether formed on a flange or as a molded-in
portion of a bag, the closure will be extruded as a continuous
strip. For some applications in which the closure is formed as part
of a flange, sections of the closure strip may be precut to desired
length before being utilized in the formation a package. In
general, the flanges of the inventive closure will be affixed to
the opening of a package, for example, a bag. The flanges may be
welded or adhered to the package opening. In some embodiments the
ends of the closure will include a crush-weld or crush-seal region
that bonds the two opposed portions of the closure together. In
some embodiments, with reference to FIG. 4, the closure will be
extruded having intermittent regions comprising a sealing material
(230) such that a length of closure which is crush-welded will
include in the weld a sealing material. In this manner the sealing
material serves as a flux, melting at a lower temperature than the
base material from which the closure is made, thus insuring that
the weld junction between the closure portions has hermetic
properties and does not permit gases to leak past the closure
crush-seal area.
[0061] In accordance with the extruded nature of the closure
described above, it will be appreciated that many of the closure
features which are described in terms of a cross-sectional shape
will be features that traverse the length of the closure. Within
the length of a closure, particularly with regard to features of
the closure which abut in providing a region of gas-sealing
abutment, local imperfections, defects, and irregularities in the
abutting closure surfaces may give rise to local void regions being
defined Moreover, in some embodiments which include a crush-weld or
crush-seal region bonding the two opposed portions of the closure
together, a void will be defined in the closure proximal to the
region of the crush seal wherein the opposed closure portions are
distorted from abutting by the weld. In other embodiments, for
example, as illustrated in FIG. 9B, features on opposed portions of
the closure will be placed proximal by engagement of the
interengaging members of the closure define a void region that
traverses the length of the closure, for example, the region
occupied by caulking composition (900) which traverses the length
of the closure between interengaging members (978, 988) which has
been gas-sealingly infiltrated by caulking composition (900,
shaded). When the opposed closure portions define either a local
void or a closure traversing void, gas-sealing abutment is provided
by gas-sealing infiltrating of a caulking compound into the void
when the interengaging members are engaged. This is discussed
herein below in detail.
[0062] As will be appreciated, the closure of the present invention
may also comprise features in common with known closures, for
example, markings to facilitate production and/or fixture of the
closure to a package, for example stripes or colored portions to
aid optical placement equipment in the assembly of a closure to a
package during manufacture of the package.
[0063] In general, the inventive closure will be prepared from a
high melt index (MI) polyolefin. In some embodiments the high MI
polyolefin has a density of at least about 0.925 g/cm3 as measured
in accordance with ASTM D1505-03 (Nov. 1, 2003). In some
embodiments, the package of which the inventive closure defines an
opening, will also be prepared from a high MI polyolefin. In some
embodiments, the package can comprise a multi-layer structure
comprising a combination of a layer of puncture-resistant polymer,
for example, nylon, and an inner layer of a sealing material, for
example polyethylene. Bags of this type are described, for example,
in U.S. Pat. No. 4,267,960 to Lind et al., which is incorporated
herein by reference in its entirety.
[0064] As will be appreciated, the structural details of the
interengaging members utilized in closures of the present invention
may vary, as illustrated, for example, in FIGS. 1-3 and 5-9 showing
cross-sectional profiles of several embodiments of the inventive
closure.
[0065] Next will be described in turn the interengaging members of
the closure and various structures related thereto, the sealing
material, and the caulking composition.
The Interengaging Members
[0066] As mentioned above, in the present closure at least one pair
of interengaging members is disposed on one of the opposed portions
of the closure. Engaging the interengaging members causes at least
one region of each of the opposed portions of the closure to
gas-sealingly abut. In one embodiment of the present closure, to
insure that continuous gas sealing abutment is provided between
opposed portions of the closure in at least one region, with
reference to FIG. 5 the closure has at least one pair of
interengaging members comprising:
[0067] (A) a first interengaging member comprising: [0068] (1) at
least one profile portion (500) affixed to the proximal face of a
first opposed portion (501) of the closure, said profile portion
comprising: [0069] (a) a first locking member (502) comprising:
[0070] (i) a first stem member (503) joined to the proximal face
(505) of said first opposing portion (501) of the closure; and
[0071] (ii) a first head member (504) affixed to the free end of
said first stem member (503); [0072] (b) a first post (506) affixed
on said first opposed portion proximal face (501) substantially
parallel and proximal to said first stem member (503), said first
post (506) disposed to define a first channel (507) with said first
head member (504), and wherein said first stem member (503), first
head member (504), and said first post (506) together are
configured and disposed to define a first void region (508); [0073]
(c) optionally a third post (509) affixed to said first opposed
portion proximal face (505) substantially parallel to said stem on
the side of the stem distal from said first post; [0074] (d)
optionally a fourth post (510) affixed to said first opposed
proximal face substantially parallel and proximal to said first
post on the side of said first post distal from said first head
member;
[0075] (B) a second interengaging member (520) comprising: [0076]
(1) at least one second locking member (522) joined to a proximal
face (525) of a second opposed portion (521) of the closure, said
second locking member (520) comprising: [0077] (a) a second stem
member (523) joined to said proximal face of a second opposed
portion of the closure (521), [0078] (b) a second head member (524)
affixed to the free end of said second stem member; [0079] (2)
optionally, a second post (526) affixed to said second opposed
portion proximal face (525) substantially parallel to said second
locking member (522), dimensioned and disposed to define a second
channel (527) with said second head member (524), wherein said
second stem member (523), said second head member (524) and said
second post (526) are configured and disposed to define a second
void region (528); and [0080] (3) optionally, when a second post is
present, a fifth post (529) affixed substantially parallel and
proximal to said second post (526) on the side of said second post
distal from said second locking member, wherein the closure is
further characterized in that each of said first and second
interengaging members are disposed such that when the proximal
faces of the opposed closure portions are brought together with an
applied engaging force, the head (524) of said second locking
member (522) is received into the channel (507) defined by said
first post (506) and first head member (504), and said second
locking member (522) is engaged within the void region (508)
defined by said first engaging member (500). In some embodiments,
for example, those illustrated in FIGS. 2, 9A and 9B, the head
member of the locking members has a cross-sectional shape which is
asymmetric relative to the centerline of the stem affixing the
locking member to the opposed closure portion. In other
embodiments, for example, those illustrated in FIG. 7, the head
member of the locking members have a cross-sectional shape which is
symmetric relative to the centerline of the stem affixing them to
the opposed closure portion.
[0081] In some embodiments one of the opposed closure portions
contains at least one locking member as a stand alone feature, for
example, with reference to FIG. 1, locking member (103). In some
embodiments, both opposing closure portions have a locking member
and post defining a channel which is rotationally symmetric with
the locking member and post on the other opposing portion of the
closure, for example, as illustrated in FIG. 2. In these
embodiments, the closure is also referred herein sometimes for
convenience as "a closure containing interlocking profiles."
[0082] In some embodiments, the interengaging portions of the
closure comprise at least one pair of interlocking profiles wherein
the head member of the stem and head portion of the profile is
mounted asymmetrically on the stem. Accordingly, the head and stem
portion of each profile, which functions as a first interengaging
member with respect to the profile mounted on the opposed portion
of the closure, has an engaging face (side of head proximal to said
stem) and a non-engaging face (side of the head distal from the
stem). In this embodiment the engaging faces of the stem and head
portion are disposed on the opposing portions of the closure in an
inverted relationship with respect to each other, and thus the
engaging faces of each head member interlock when the opposing
profiles are engaged. In one embodiment having interlocking
profiles, for example, as illustrated in FIG. 2, the stems (231,
232) and head member (204, 224) of each opposing locking member
(203, 223) has a cross-sectional profile comprising a "J"-shape,
disposed such that the stem and head member(s) of each opposing
profile are positioned with the projecting portion of the "J"-shape
defining the engaging face of the head member such that the stem
and head member of the profile on each opposing portion of the
closure are in an inverted relationship with respect to the stem
and head member of corresponding interlocking profile on the
opposed portion of the closure.
[0083] In some embodiments, the interengaging members of the
closure comprise multiple locking members affixed to each of the
opposing portions of the closure disposed such that upon engagement
of said interengaging members said opposed multiple locking members
are interdigitated.
[0084] In another embodiment of the present invention, the
resealable closure device further comprises more than one set of
interengaging members, for example, two sets of interlocking
profiles positioned in close proximity and substantially parallel
to each other. For example, as illustrated in FIGS. 9A, 9B and 10.
In one embodiment having multiple pairs of interlocking profiles, a
bead of caulking composition may be positioned within the space
separating the substantially parallel sets of opposed interlocking
profiles.
[0085] In some embodiments, for example, those illustrated in FIGS.
7 and 8, the closure comprises interengaging members comprise a
series of locking members affixed to each of the opposed portion of
the closure, which interdigitate when the opposed portions are
brought together with an engaging force. Accordingly, with
reference to FIG. 7, the interengaging members can comprise
multiple locking members (766, 762) and (764, 760) affixed to each
proximal face accompanied by one or more posts (782 and 780,
respectively), which are configured symmetrically and disposed such
that the post and locking members affixed to the proximal face of
one opposed portion (e.g., 780, 764 and 760) define a complimentary
void region in which the heads of the locking members affixed to
the other opposed portion (782, 762 and 766) are engaged when the
opposed portions of the closure are brought together with an
engaging force. In the example illustrated in FIG. 7, the heads of
locking members (760, 762, 764 and 766) are affixed to their
respective stems such that they are in cross-section symmetrically
disposed on the stem. The posts contain an asymmetric shape which
compliments the post and stem of the adjacent locking member to
define a void region between the post and locking member suitable
to engage the locking member affixed to the opposed closure
portion.
[0086] Alternatively, as illustrated in FIG. 8, the heads of
locking members (868, 866, 864 and 863, 865, 867) are attached
offset on their respective stems by which they are affixed to
opposed closure portions (852 and 850, respectively). Accordingly,
they have an asymmetric cross-sectional profile. Moreover, the two
sets of locking members are disposed on their respective opposed
closure portions such that they are rotationally symmetric, the
offset portion of the head of locking members (868, 866 and 864)
being disposed to engage the offset portion of the head of locking
members (867, 865 and 863, respectively). Posts (880, 882) are
configured to compliment the configuration of the non-offset face
of locking members (868, 863, respectively).
[0087] As mentioned above, numerous configurations of interengaging
members will be suitable for use in a closure of the present
invention, so long as they provide sufficiently robust engagement
to maintain the closure in a sealed condition under the conditions
of use. In general, when engaged the interengaging members hold one
or more portions of the closure in proximity to define a void
region into which a caulking composition is gas-sealing
infiltrated, or place one or more features on each of the opposed
portions of the closure into mechanical abutment which, in
conjunction with a caulking composition associated with the abutted
features and/or a sealing material incorporated into at least one
of the abutted features, provides at least one region of
gas-sealing abutment between the opposed closure portions.
[0088] Mechanical abutment can be provided by selecting the
dimensions and/or placement of closure features. For example, with
reference to FIG. 6, mechanical abutment can be provided by
selecting the dimensions of parts of the interengaging members to
create an interference fit between the engaging portions of the
interengaging members. For example, by selecting the dimensions for
the closure parts illustrated such that the gap between post (606)
and head member (615) of interengaging member (650) is narrower
than the width of stem (623) of locking member (624) provides
abutment between the sides and head of locking member (614) and
stem (623) of locking member (624). Alternatively, abutment can be
provided by two features not associated with the interengaging
members, for example, with reference to FIG. 5, selecting the
dimensions of post (509) to abut flange (521) in the region between
posts (526, 529) when the interengaging members are engaged.
[0089] Alternatively, the placement of multiple pairs of
interengaging members can be selected to provide mechanical
abutment between features affixed to opposed portions of the
closure. Accordingly, with reference to FIG. 9A, selecting the
disposition of locking member (910) and the center of the channel
defined by post (911) and head member (904) to be greater or lesser
than the distance between locking member (920) and the center of
the channel defined by post (924) and head member (921) forces
abutment between various portions of the pair of interengaging
members when the two pairs of interengaging members are
engaged.
[0090] Additional features may also be provided on at least one of
the opposed portions of the closure to provide mechanical abutment
with a feature on the other opposed portion of the closure. For
example, with reference to FIG. 9, a bead of sealing material (945)
disposed on opposed closure portion (952) to abut the back side of
locking member (905) will provide a region of gas-sealing abutment
when the interengaging members are engaged. It will be appreciated
that numerous other arrangements of the features of the closure can
be utilized to provide an abutting interaction between at least one
region of each of the opposed closure portions which, when coupled
with a caulking composition and/or a sealing material provides
gas-sealing abutment.
[0091] In some embodiments, the interengaging members are provided
with locking members having a portion that comprises a sealing
material, described in detail herein below. With reference to, for
example, FIG. 8, locking members (864, 866 and 868) comprise
sealing material (899) disposed as a bead traversing the length of
the locking member head, in the center of the head of each locking
member. In this manner, when the interengaging members on opposed
closure portions (850, 852) are interdigitated, the bead of sealing
material (899) is abutted to the opposed closure portion, as
described below, providing a gas-sealing abutment.
[0092] Interengaging members are known, for example, those used in
conventional resealable closures, for example, as described in U.S.
Pat. Nos. 5,356,222, 5,252,281 and 5,248,201, each of which is
incorporated herein by reference in its entirety. These known
closure can be employed in the present invention so long as they
are sufficiently robust in their engaging properties to maintain
sealing abutment in the closure and additionally, they employ means
for insuring at least one region of gas-sealing abutment between
opposing portions of the closure when the closure portions are
engaged. Examples of means for insuring gas-sealing abutment
include, for example, a caulking composition disposed to
gas-sealingly infiltrate voids defined in the abutting regions of
the closure and a sealing material provided in one or more of the
abutting regions of the closure, as described in detail herein.
The Caulking Composition
[0093] In closures of the present invention, the closure comprises
a caulking composition gas-sealingly infiltrated into at least one
void defined by proximal features of opposing portions of the
closure when the interengaging members of the closure are engaged
or defined by incomplete mechanical abutment between abutting
features affixed to opposing portions of the closure. Accordingly,
prior to engagement of the interengaging member, the caulking
composition is associated with portions of the closure which either
will mechanically abut upon engagement of the closure, or
associated with features of the closure that will impinge the
caulking compound in defining a void region by their proximity when
the interengaging members of the closure are engaged, thereby in
either case gas-sealingly infiltrating the void region or regions
defined by the opposed portions of the closure.
[0094] With reference to FIG. 2, the void defined by a region of
abutment between the pair of opposed closure portions upon engaging
the locking members (231, 232) of the interengaging members of the
closure of FIG. 2 can be a small localized gap, for example, one
that exists over just a localized region, for example, region (220)
defined by the engaged interengaging members of the closure where
there is a gap in mechanical abutment. Alternatively, or
additionally, with further reference to FIG. 2, a caulking compound
can be infiltrated into a gap traversing the closure which is
defined by features on each of the opposed portions of the closure
maintained proximal by engagement of the interengaging members, for
example, the void illustrated as region (250, shaded), which
extends the length of locking members (231, 232), between locking
member (232) and flange (201).
[0095] Thus, for example, as illustrated in FIG. 3, a bead of
caulking composition can be distributed on locking member (324)
and/or in the channel defined by locking member (303) and post
(304) prior to engagement of the interengaging members, which will
be distributed, by virtue of mechanical abutment of the closure
features, within any voids present in the members when engagement
occurs, and thus gas-sealingly infiltrated into at least one void
defined between the locking members of the opposed closure
portions. In addition, or alternatively, a bead of caulking can be
placed in or along a feature on one or both opposing portions of
the closure where a feature affixed to one opposing portion of the
closure closely approaches a feature on the other opposing portion
of the closure. Accordingly, the closely approaching feature(s)
contact the caulking bead and distribute the caulking composition
within the void defined between the proximal opposing closure
portions. For example, with reference to FIG. 3, a bead of caulking
composition placed into the well formed by post (313) and locking
member (303) will be gas-sealingly infiltrated into the void
defined by post (333) and region (314) when the interengaging
members are engaged by virtue of the caulking bead being impinged
by post (333) upon engagement of the interengaging members. A
further illustration is with reference to FIG. 9B, wherein a bead
of caulking material residing on opposing closure portion (901)
between interengaging members (978, 988) is impinged by locking
member (987) upon engagement of the interengaging members, and
gas-sealingly infiltrated (900) within the void defined by locking
member (987) and proximal face (902) of opposing portion (901)
between the pairs of interengaging members.
[0096] In some embodiments a caulking composition is associated
with multiple regions of the opposed closure portions including the
interengaging members and features remote from the interengaging
members that are abutted when the interengaging members are
engaged. It will be appreciated that the physical properties of the
caulking composition and the dimensions and features of the closure
can be selected to provide closures having many other shapes and
sizes of abutting features and features defining void areas, and
associated therewith, disposed to gas-sealingly infiltrate one or
more voids defined by these closure portions, a caulking
composition.
[0097] In some embodiments the caulking composition is placed on or
proximal to selected areas of the closure to seal portions of the
closure that are prone to have gaps, for example, applied to the
ends of a closure near a crush area affixing opposing portions of
the closure together. In some embodiments the caulking composition
is applied to the closure as a continuous bead along the closure,
for example, on or between one or more of the interengaging members
of the closure.
[0098] In closures of the present invention, the constituents of
the caulking composition are selected such that when the caulking
composition infiltrates one or more voids defined by the engaged
interengaging members of the closure, it imparts a gas and vapor
permeation-resistant seal to that portion of the closure. Thus, the
caulking composition is selected generally to have an affinity for
the materials of construction of the closure and to resist
degradation in the ambient environment. Moreover, in general the
caulking composition maintains plastic characteristics under the
conditions of use such that it will flow under applied pressure,
for example, pressure suitable to engage the interengaging
members.
[0099] In some embodiments the caulking composition comprises a
mixture suitable for at least incidental contact to food items and
in some embodiments it is suitable for direct food contact. In some
embodiments the caulking composition comprises constituents such
that it maintains caulking properties without denaturing or
separating over a temperature range of from about -10.degree. F. to
about +160.degree. F. In some embodiments the caulking composition
is selected to change state from a free-flowing liquid, for
example, at a temperature at which a fill is provided within the
package, for example, about 65.degree. F., to a viscous semi-solid,
for example, at a temperature at which the filled package is
stored, for example, about (minus) -40.degree. F.
[0100] In one embodiment the caulking composition comprises liquid
silicone and a filler, e.g. fumed silica, in proportions to provide
a grease with a grease consistency number of approximately 2.0, as
characterized by National Lubricating Grease Institute (NGLI)
standards. In one embodiment the caulking composition comprises a
soy adhesive, such as Pro-Cote.RTM. soy polymer available from
DuPont.TM.. In another embodiment, the caulking composition
comprises soy oils, for example, those available from Cargill.TM.
Industrial Oils & Lubricants. In one embodiment the caulking
composition comprises two reactive constituents, each residing on a
different portion of the closure, such that when the interengaging
profiles of the closure are engaged the two constituents are
admixed, providing a reaction product which infiltrates at least
one void defined by the interengaging closure profiles. For
example, with reference to FIG. 5, a bead of reactant (540) which,
upon engaging the interengaging members, admixes with a bead of
reactant (541) when post (509) contacts flange (521) in the
vicinity of reactant (541).
The Sealing Material
[0101] In some embodiments, one or more portions of the closure
comprise a sealing material. In some embodiments comprising a
sealing material the material is selected to have a high degree of
conformance and is disposed on the closure to gas-sealingly abut an
opposing portion of the closure. In some embodiments at least one
portion of the closure includes a coextruded bead of sealing
material, for example, a bead along a portion of a profile or a
bead along the head of a locking member. In some embodiments
comprising a sealing material, the closure comprises a sealing
material incorporated into a welded area of the closure, for
example, a crush seal at a closure end.
[0102] With reference to FIG. 1, region (102) of opposed closure
portion (101), which is located at the bottom of a well defined by
adjacent posts (103, 104) affixed to opposed portion (101),
comprises a sealing material. When the interengaging members (104,
120) are engaged, post (123), which is affixed to opposed closure
portion (121), will abut the region of the closure comprising
sealing material (102). Post (123) is formed from a high melt
polyolefin which is harder than the sealing material. Accordingly,
the region of sealing material will yield and conform to the end of
post (123), thereby establishing gas-sealing abutment between post
(123) and the region of sealing material (102). As will be
appreciated, a sealing material could also, or alternatively, be
placed in the region between post (123) and locking member (124).
In this case, engagement of the interengaging members would abut
post (104) to region (125), and in the example wherein region (125)
comprises a sealing material, thereby establishing gas-sealing
abutment between these two closure features.
[0103] In some embodiments at least one portion of the closure
includes a coextruded sealing material, for example, as described
in each of U.S. Pat. Nos. 5,356,222, 5,252,281 and 5,248,201, each
of which is incorporated herein by reference in its entirety. In
some embodiments having a sealing material, the sealing material
comprises a material selected from low melt index polymers, for
example, a low density polyolefin, for example, polyolefin having a
density of less than about 0.925 g/cm3 as measured in accordance
with ASTM D1505-03 (Nov. 1, 2003), low density polyurethane and
polyolefin containing an amount of vinyl acetate to yield a blend
having a low melt index, as measured in accordance with ASTM
standard ASTM D-1238-04c. For example a melt index of about 7. In
some embodiments the sealing material has a melt index of from
about 5 to about 9, preferably, from about 5 to about 7, and, more
preferably, about 7. In some embodiments the sealing material
provides a region in the closure which insures the formation of a
leak-free seal when the closure flange is fused to another
material, for example, the opening of a package, or when opposing
portions of the closure are fused together at the ends of the
closure to form an end seal. In some embodiments the sealing
material provides a region in the closure having a high degree of
conformance with a portion of the closure in which the sealing
material engages in compressive abutment, for example, upon
engaging the interengaging member and profile portions of the
closure, thereby providing for a reduction or elimination in the
void areas present between the opposed portions of the closure and
thus providing a seal having reduced gas permeability. In some
embodiments the sealing material comprises a portion of one or both
opposed portions of interengaging closure members. In some
embodiments the sealing material comprises a portion of the flange
or of a post of the closure which is compressively abutted by a
feature on the opposite flange when the interengaging members are
engaged. In some embodiments the sealing material comprises the
entire length of at least one portion of at least one closure
profile. In some embodiments the sealing material comprises
selected portions of at least one closure profile, for example, the
periphery portions of the closure.
[0104] Having described the presently preferred embodiments, it is
to be understood that the invention may be otherwise embodied
within the scope of the appended claims.
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