Information
-
Patent Grant
-
6402377
-
Patent Number
6,402,377
-
Date Filed
Monday, May 22, 200024 years ago
-
Date Issued
Tuesday, June 11, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
A drawtape bag comprising a pair of pliable thermoplastic body panels, a pliable drawtape and an elastomeric strip. The pair of pliable thermoplastic body panels are joined to each other along a pair of opposing sides and a bottom bridging the opposing sides. At least one of the body panels forms a hem extending along a mouth end disposed opposite the bottom. The hem includes one or more drawtape holes. The pliable drawtape is housed within the hem and includes a gathered section. The drawtape is partially exposed by the drawtape holes which allow the drawtape to be pulled therethrough to close the bag and to be used as a handle. The elastomeric strip is connected to the gathered section of the drawtape. The elastomeric strip comprises behenamide to inhibit or prevent blocking of the elastomeric strip to the hem or drawtape.
Description
FIELD OF THE INVENTION
The present invention relates generally to plastic packages and, more particularly, relates to a drawtape bag having a strip that has reduced blocking to itself as well as other surfaces.
BACKGROUND OF THE INVENTION
Sealable polymeric packages, such as trash bags, are a common household item. The bags come to the consumer in the form of a roll of interconnected bags or as pre-separated bags housed in a dispensing box. When the bags are provided in the form of a roll, one end of the bag, the bottom, is thermally sealed closed and connected to its neighboring bag along a perforated line; the other end of the bag, the open mouth end, is attached to its neighboring bag solely along another perforated line. When the bags are pre-separated, neighboring bags are generally overlapped or interweaved in such a manner that removal of one bag from the dispensing box draws the neighboring bag toward an opening in the box.
To close a typical polymeric bag after it has been filled by the consumer, the bag body adjacent the open mouth end of the bag is gathered and tied into a knot or secured using a separate tie member supplied by the vendor of the bags. Tie members typically include paper coated flexible wires, rubber bands, or strips of plastic having a locking mechanism to provide a means to pull tight and securely fasten the neck of the bag. The need for separate tie members, however, adds an additional cost factor for the manufacturer, and ultimately, the consumer. In addition, separate tie members are easily lost and hence can be a nuisance for the consumer. Polymeric packages having integral closure systems overcome these problems. Such integral closure systems can be in the form of tie members, adhesives and the like.
One particularly advantageous closure system is a drawtape or drawstring that is integral to the bag body. Bags of this type are typically in the form of a pair of pliable thermoplastic body panels joined to each other along a pair of opposing sides and a bottom bridging the opposing sides. The bag may be opened along a mouth end formed opposite the bottom. The body panels form a hem along the mouth end of the bag, and the hem houses a pliable thermoplastic drawtape. One or more drawtape holes located within the hem expose the drawtape allowing it to be pulled through the holes to close the bag and to be used as a handle.
When consumers use a drawtape bag as a liner for a trash container, the bag body is inserted into the trash container such that the bag body generally extends downward into the trash container. The mouth end of the bag, including the hem, is drawn over and loosely mounted around an upper portion of the trash container. A shortcoming of such drawtape bags has been that the mouth end of the bag might fall back into the trash container, especially when consumers discard trash into the bag. This can be a nuisance for the consumer, who must then lift the mouth end of the bag out of the trash container and around the upper portion thereof. If the consumer does not notice that the mouth end of the bag has fallen into the trash container, the consumer might discard trash that is not captured by the drawtape bag but rather contacts and possibly sullies the inside wall of the trash container. This defeats the purpose of the bag, which is to serve as a liner for the trash container.
The use of some materials in forming the bag may also result in a condition termed blocking. Blocking is the undesired adhesion between layers of plastic materials in contact with each other. Blocking may prevent or inhibit portions of the bag from being able to move freely against another surface, such as the drawtape in a hem of a bag. Blocking may be caused by tacky materials or static electricity and may be exacerbated by higher temperatures and pressures. Higher temperatures and/or pressures are commonly encountered in hot warehouses. These warehouses may store material to be used in the bags, as well as storing the drawtape bags in boxes that are stacked. Winding tends to induce even higher pressures between the layers of film since polymers are extensible and the winding tension creates pressure in the roll.
Therefore, a need exists for a drawtape bag that overcomes the above-noted problems.
SUMMARY OF THE INVENTION
According to one embodiment, a drawtape bag comprises a pair of pliable thermoplastic body panels, a pliable drawtape and an elastomeric strip. The pair of liable thermoplastic body panels are joined to each other along a pair of opposing sides and a bottom bridging the opposing sides. At least one of the body panels forms a hem extending along a mouth end disposed opposite the bottom. The hem includes one or more drawtape holes. The pliable drawtape is housed within the hem and includes a gathered section. The drawtape is partially exposed by the drawtape holes which allow the drawtape to be pulled therethrough to close the bag and to be used as a handle. The elastomeric strip is connected to the gathered section of the drawtape. The elastomeric strip comprises behenamide.
According to another embodiment, a drawtape bag includes a pair of thermoplastic body panels, a pair of pliable drawtapes and a pair of elastomeric strips. The pair of pliable thermoplastic body panels are joined to each other along a pair of opposing sides and a bottom bridging the opposing sides. The body panels form respective hems extending along a mouth end disposed opposite the bottom. Each of the hems includes one or more drawtape holes. The pair of pliable drawtapes is housed within the respective hems. Each of the drawtapes includes a gathered section. Each of the drawtapes is partially exposed by the respective drawtape holes which allow the respective drawtape to be pulled therethrough to close the bag and to be used as a handle. The pair of elastomeric strips is connected to the gathered section of the respective drawtapes. Each of the elastomeric strips comprises behenamide.
According to a further embodiment, a drawtape bag comprises at least one pliable thermoplastic body panel, a pliable drawtape and an elastomeric strip. At least one pliable thermoplastic body panel has a top and bottom portion. At least one body panel forms a hem extending along the top portion opposite of the bottom portion. The hem includes one or more drawtape holes. The pliable drawtape is housed within the hem and includes a gathered section. The drawtape is partially exposed by the drawtape holes which allow the drawtape to be pulled therethrough to close the bag and to be used as a handle. The elastomeric strip is connected to the gathered section of the drawtape and comprises behenamide.
According to yet another embodiment, an article comprises at least one pliable thermoplastic body panel and an elastomeric strip. The at least one pliable thermoplastic body panel has a top and bottom portion, and forms a hem extending along the top portion opposite of the bottom portion. The elastomeric strip comprises behenamide and is housed within the hem.
The above summary of the present invention is not intended to represent each embodiment, or every aspect of the present invention. This is the purpose of the figures and detailed description which follow.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
FIG. 1
is a side view of a drawtape bag with elastic top feature according to one embodiment of the present invention;
FIG. 2
is a cross-sectional view of an elastomeric strip attached to a looped section of a drawtape used in the drawtape bag, where the elastomeric strip is shown in unstretched form;
FIG. 3
is a cross-sectional view of the elastomeric strip attached to the looped drawtape section, where the elastomeric strip is shown in partially stretched form;
FIG. 4
is an isometric view of the drawtape bag of
FIG. 1
securely mounted to a trash container;
FIG. 5
is an isometric view of the drawtape bag of
FIG. 1
removed from the trash container and closed using its drawtapes;
FIG. 6
is a schematic view of a method of manufacturing the drawtape bag.
FIG. 7
is a top view of a first sample to be used in a procedure to measure blocking force;
FIG. 8
is an isometric view of a second sample to be used in a procedure to measure blocking force;
FIG. 9
a
is a side view of a structure including first samples of
FIG. 7
between two metal templates in one step of the procedure to measure blocking force;
FIG. 9
b
is a side view of a structure including second samples of
FIG. 8
between two metal templates in one step of the procedure to measure blocking force;
FIG. 10
a
is a side view of the first sample of
FIG. 7
between two jaws in another step of the procedure to measure blocking force; and
FIG. 10
b
is a side view of the second sample of
FIG. 8
between two jaws in another step of the procedure to measure blocking force.
While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will be described in detail. It should be understood, however, that it is not intended to limit the invention to the particular form described, but, on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
Turning now to the drawings,
FIG. 1
illustrates a drawtape bag
10
comprising a pair of pliable thermoplastic body panels
12
and
14
(panel
14
is hidden beneath panel
12
in
FIG. 1
, but can be seen in
FIG. 4
) joined to each other along a pair of opposing sides
16
a
and
16
b
and a bottom
18
bridging the opposing sides
16
a
and
16
b
. The bag
10
may be opened along a mouth end
20
formed opposite the bottom
18
. Each of the body panels
12
and
14
forms a respective hem
22
along the mouth end
20
of the bag
10
. The hem
22
on each panel
12
and
14
houses a respective pliable thermoplastic drawtape
24
. To maintain the drawtape
24
within the hem
22
, the hem
22
is thermally sealed to the respective panel
12
and
14
along a respective hem seal
23
.
A pair of drawtape holes
26
a
and
26
b
are located in the hem
22
on each panel
12
and
14
at the respective sides
16
a
and
16
b
. The drawtape holes
26
a
and
26
b
in the hem
22
on the panel
12
coincide with the respective drawtape holes
26
a
and
26
b
in the hem on the other panel
14
. The drawtape
24
housed within the hem
22
on the panel
12
is thermally sealed to the drawtape housed within the hem on the panel
14
at seals
28
a
and
28
b
coinciding with the respective drawtape holes
26
a
and
26
b
. The drawtape holes
26
a
and
26
b
provide a heat sealing bar with access to the drawtapes
24
for generating the drawtape seals
28
a
and
28
b
. Furthermore, when the drawtapes
24
are fully installed into the bag
10
, the holes
26
a
and
26
b
expose the drawtapes
24
allowing them to be pulled through the holes
26
a
and
26
b
to close the bag and to be used as a handle as depicted in FIG.
5
.
The drawtape bag
10
includes an elastic top feature that enables the bag
10
to be securely fitted to the upper portion of a trash container lined with the bag
10
and, at the same time, does not interfere with the intrinsic strength and operation of the drawtape
24
. The elastic top feature is provided by an elastomeric strip
30
connected to a gathered section
32
of the drawtape
24
housed within the hem
22
on each panel
12
and
14
. Specifically, the gathered section
32
is gathered into a plurality of loops defining a series of crests
35
and troughs
34
, and each trough is thermally sealed to the elastomeric strip
30
. This is best shown in
FIG. 2
, which is a cross-sectional view depicting the elastomeric strip
30
attached to the gathered section
32
at the troughs
34
. The elastomeric strip
30
has a total length of less than the length of the drawtape
24
and preferably about equal in dimension to the footprint of the gathered section
32
. The footprint of the gathered section
32
may be defined as the horizontal distance between the leftmost trough
34
and the rightmost trough
34
as viewed in FIG.
2
.
Referring back to
FIG. 1
, the drawtape
24
is sealed in four specific locations along the mouth end
20
of the bag
10
. The drawtape seals
28
a
and
28
b
referenced above are two of these sealed locations. Third and fourth sealed locations are provided by an anchor seal
38
found in the center of the hem
22
on each panel
12
and
14
. The anchor seal
38
unitizes the drawtape
24
with adjacent layers of the hem
22
.
Referring to
FIG. 4
, the drawtape
24
allows the mouth end of the drawtape bag
10
, including the hems
22
, to be drawn over and securely mounted around an upper portion of a trash container
36
. Depending upon the size of the trash container
36
, mounting the bag
10
to the container
36
stretches the elastomeric strip
30
, thereby increasing the “wavelength” of each loop in the gathered section
32
and decreasing the height of the crests
35
.
FIG. 3
is a cross-sectional view of the elastomeric strip
30
attached to the gathered section
32
, where the elastomeric strip
30
is shown in partially stretched form. The elastomeric strip
30
can be stretched up to the point where the length of the stretched elastomeric strip
30
equals the length of the drawtape making up the gathered section
32
, i.e., where the “wavelength” of each loop reaches a maximum and the height of the crests
35
reaches zero. Beyond that point, the tensile characteristics of the non-elastic drawtape
24
control the behavior of the two component construction, one component being provided by the drawtape
24
and the other component being provided by the elastomeric strip
30
. The two component construction effectively combines the elastic behavior of the elastomeric strip
30
with the strength characteristics of the non-elastic drawtape
24
. The elastomeric strip
30
enables the bag
10
to be securely fitted to the upper portion of a trash container lined with the bag
10
.
The elastomeric strip
30
also comprises behenamide that assists in inhibiting or preventing blocking of the elastomeric strip to itself and other films. For example, the elastomeric strip
30
with behenamide inhibits or prevents blocking of the strip
30
to the draw tape
24
and the hem
22
of the drawtape bag
10
. The addition of behenamide to the elastomeric strip
30
also inhibits or prevents blocking to itself when being wound as a roll. The elastomeric strip
30
of the present invention preferably does not stick to itself or to surfaces of other films (e.g., polyethylene) at room and elevated temperatures.
The elastomeric strip
30
is comprised of a polymeric material and has a low yield strength and high elasticity as compared to the respective yield strength and elasticity of a polyethylene drawtape
24
. One type of elastomer is a material that at room temperature may be stretched at least a few times to about twice its original length and, then upon release of the stress, return with force to its approximate original length. In general, elastomers generally are more extensible than conventional polyethylene films, such as low density polyethylenes (LDPEs), high density polyethylenes (HDPEs) and linear low density polyethylenes (LLDPEs).
The elastomeric strips of the present invention are typically made from polyolefinic material having elastic properties. The elastomeric strips may be made from materials such as styrene butadiene copolymers (SBCs) and ethylene-propylene diene monomers (EDPMs), which are also referred to as terpolymer elastomers. The elastomers may be ethylene based, such as an elastomeric polyethylene. The ethylene based elastomers typically have a high level of comonomer such as hexene or octene. The ethylene based elastomers generally have a density from about 0.800 g/cm
3
to about 0.915 g/cm
3
, and more typically from about 0.870 g/cm
3
to about 0.905 g/cm
3
.
Other contemplated elastomers include the following: acrylonitrile-chloroprene copolymers; acrylonitrile-isoprene copolymers; butadiene-acrylonitrile copolymers; chlorinated polyethylenes; chlorosulfonated polyethylenes; ethylene ether polysulfides; ethylene-ethyl acrylate copolymers; ethylene polysulfides; ethylene-propylene copolymers; fluoroelastomers; fluorosilicones; hexafluoropropylene-vinylidene fluoride copolymers; isobutene-isoprene copolymers; organopolysiloxanes; acrylic ester-butadiene copolymers; polybutadienes; polychloroprenes; polyepichlorohydrins; polyisobutenes; polyisoprenes; polyurethanes; polyethylene-butyl graft copolymers; and styrene-butadiene-styrene triblock polymers.
In general, the tendency of polyolefins to block is related to density. Lower density polyolefins generally tend to block more severely than higher density polyolefins. Elastomers are one of the lowest density polyolefins available, and thus, tend to block more severely than higher density polyolefins such as low density polyethylenes, high density polyethylenes and linear low density polyethylenes.
An example of an elastomer that may be used in the present invention is Dow Chemical's AFFINITY KC8852. The AFFINITY KC8852 resin has a density of 0.875 g/cm
3
and a melt index of 3.0 g/10 min. as determined by ASTM D1238. The AFFINITY KC8852 is an ethylene-octene copolymer. Another example of an elastomer that may be used is Exxon's EXACT 4049 resin. The EXACT 4049 resin has a density of 0.873 g/cm
3
and a melt index of 4.5 g/10 min. as determined by ASTM D1238.
As discussed above, the elastomeric strips
30
of the present invention comprise behenamide. Behenamides are generally defmed by one of the following formulas: CH
3
(CH
2
)
18
CONH
2
and CH
3
(CH
2
)
20
CONH
2
. An example of behenamide that may be used in making the drawtape of the present invention is marketed by Croda, Inc. as Crodamide BR, refined behenamide.
The elastomeric strips may be made of blends or coextruded materials. For example, the elastomeric strips may include an elastomeric material that is blended with other elastomeric materials or non-elastic materials.
The elastomeric strip
30
of the present invention generally comprises at least about 50 wt. % elastomer, typically at least about 75 wt. % elastomer and preferably at least about 90 wt. % elastomer and more preferably at least about 95 wt. % elastomer. The elastomeric strip
30
generally comprises from about 500 ppm to about 20,000 ppm (2.0 wt. %) of behenamide, preferably from about 1,000 ppm to about 5,000 ppm of behenamide and more preferably from about 2,000 ppm to about 4,000 ppm of behenamide.
According to another embodiment, the elastomeric strip
30
comprises an elastomer, behenamide and erucamide. Erucamide is generally considered a slip agent. Slip agents generally act as an internal lubricant by migrating to the surface of the plastic during and immediately after processing to reduce friction and improve slip.
It is contemplated that slip agents other than erucamide may be used in the present invention such as oleamide, glycerol monostearate (GMS), silicone, stearamide or combinations thereof. The slip agents may be a part of a masterbatch that includes a base resin. For example, erucamide may be included with a base resin such as a linear low density polyethylene. The elastomeric strip generally comprises from 0 to about 2,000 ppm and more specifically from about 300 to about 1,000 ppm slip agent.
It is contemplated that anti-blocking agents may be added to the elastomeric strip
30
. These anti-blocking agents include materials such as talc, silica, diatomaceous earth or combinations thereof.
It is contemplated that other additives may be used in forming the elastomeric strip. For example, a process aid may be desirable in reducing or eliminating melt fracture or a coloring additive may be added.
The elastomeric strip
30
generally has a thickness from about 0.5 mil to about 100 mils and more specifically from about 1 mil to about 10 mils, and from about 4 mils to about 7 mils. The elastomeric strips
30
of the present invention may be wound on reels for storage.
With respect to a typical drawtape bag embodying the present invention, the body panels
12
and
14
may be made from a wide range of polymeric materials such as linear low density polyethylene, low density polyethylene, high density polyethylene, high molecular weight high density polyethylene, polypropylenes, other polyolefins, polystyrenes or combinations thereof. In addition, the body panels may comprise more than one layer by using, for example, two or more of the above polymers. In a multi-layered body panel, the layers of the body panels may be coextruded. Each body panel generally has a thickness of from about 0.2 mil to about 5 mils and more specifically from about 0.4 mil to about 2 mils.
The drawtape
24
comprises a polymeric material having a high yield strength and low elasticity in the draw direction. These properties mean that when the drawtape
24
is subjected to high stresses in the draw direction, the drawtape
24
substantially maintains its shape and does not stretch from its original length. When some prior art drawtapes are pulled hard to close the bag, the drawtape elongates over most of its length and the area where it is gripped by the hand becomes narrow, or “ropes,” and hurts the hand. The polymeric material of the drawtape preferably minimizes this “roping” effect. Suitable polymers include, but are not limited to, high molecular weight density polyethylenes, medium density polyethylenes (MDPEs), linear low density polyethylenes, low density polyethylenes, polyesters, polystyrenes, polypropylenes and combinations thereof The drawtape generally has a thickness from about 1 mil to about 5 mils, where a thicker drawtape is desired for bags intended to carry heavier loads.
It is contemplated that the drawtape of the present invention may be made according to other embodiments. For example, a drawtape system may be comprised of two separate drawtapes. Each of the drawtapes are sealed at opposing side seals of the bags. The drawtapes are typically sealed to the opposing side seals via each of its ends. Each of the drawtapes, after being fully installed in the bag, is exposed via holes that are located in the general center of each drawtape. The holes expose the drawtape portions to be used as a handle.
According to another contemplated embodiment of the present invention, a drawtape bag includes at least one pliable thermoplastic body panel, a pliable drawtape and an elastomeric strip. At least one pliable thermoplastic body panel has a top and bottom portion. At least one body panel forms a hem extending along the top portion opposite of the bottom portion. The hem includes one or more drawtape holes.
According to yet another embodiment, an article or bag comprises at least one pliable thermoplastic body panel and an elastomeric strip. The at least one pliable thermoplastic body panels has a top and bottom portion. The at least one body panel forms a hem extending along the top portion opposite of the bottom portion. The elastomeric strip comprising behenamide and is housed within the hem. The article or bag may be in the form of a diaper, shower cap or a laundry bag. The hem may optionally include one or more holes to assist in manufacturing the article.
Methods of Manufacture
FIG. 6
is a schematic view of a method of manufacturing drawtape bags
10
. First, a thermoplastic tube
50
is extruded in a machine direction (MD), flattened by rollers in a flattening mechanism
51
, and then slit in half by a static slitting mechanism
52
along a center line
54
. Each half
50
a
and
50
b
of the tube
50
includes a pair of pliable thermoplastic sheets joined to each other along a bottom
18
disposed in the machine direction. The machine direction is designated by an arrow labeled MD in FIG.
6
. The sheets are separable from each other along a mouth end proximate to center slit line
54
and opposite the bottom
18
.
Second, the sheets are passed through a static folding mechanism
56
in the machine direction (MD) to produce a hem
22
on each sheet along the mouth end
20
.
Third, a single-hole cutting mechanism
58
creates drawtape holes
26
in the hem
22
on each sheet at regular distance intervals corresponding to a predetermined width of the drawtape bags
10
produced by the manufacturing method. The drawtape holes
26
in the hem
22
on one of the sheets coincide with the respective drawtape holes in the hem on the other of the sheets.
Fourth, a pliable thermoplastic drawtape
24
from a supply roll (not shown) is continuously fed and inserted into the hem
22
on each sheet. The drawtape
24
has gathered sections
32
disposed at regular distance intervals along the drawtape
24
corresponding to the predetermined width of the drawtape bags
10
produced by the manufacturing method. Prior to insertion, elastomeric strips
30
with behenamide are attached to the respective gathered sections
32
of the drawtape
24
as described above in connection with
FIGS. 1-5
.
Fifth, a static heat sealing mechanism
60
generates a hem seal
23
in the machine direction (MD) which attaches the hem
22
on each sheet to the respective sheet.
Sixth, a heat sealing mechanism
62
generates drawtape seals
28
which attach the drawtape
24
housed within the hem
22
on the one of the sheets to the drawtape housed within the hem on the other of the sheets at the locations of the coinciding drawtape holes
26
. These drawtape seals
28
are transverse to the machine direction (MD). The heat sealing mechanism
62
also creates the anchor seal
38
(see FIG.
1
).
Seventh, a heat sealing and perforation mechanism
63
generates side seal structures
64
transverse to the machine direction (MD) and disposed at regular distance intervals corresponding to the predetermined width of the drawtape bags
10
produced by the manufacturing method. Each side seal structure
64
includes a perforation line disposed between a pair of spaced seal lines. The perforation line allows the sheets to be separated into the individual drawtape bags
10
. The bags
10
may then be packaged in a dispensing box for sale to consumers.
EXAMPLES
Various strip compositions were made and tested with the results shown in the Table below. Strips
1
-
5
, with various compositions, are shown in the Table. Strips
1
-
5
were tested for peel forces (elastomeric strip to elastomeric strip and elastomeric strip to a polyethylene (“PB”) film). As shown in the Table, Strips
1
-
5
were comprised of various amounts of elastomer, talc, behenamide, glycerol monostearate (GMS) and erucamide.
Strips
1
-
5
were all prepared from a single extruder with a screw diameter of 1.25 inch using the same processes. Atfter Strips
1
-
5
were made, Strips
1
-
5
were then maintained at a temperature of 140° F. in an oven for seven days. After this time duration, each of the Strips
1
-
5
was tested using a peel force test procedure. A Kayness Block/ieblock test was not performed because the Strips
1
-
5
were too small to use the Kayness to measure blocking force. The procedure for the peel force test used is described as follows.
Peel Force Test
1. 2 sets of the 5 strips were made. The specific materials for each Strip
1
-
5
are shown below in the Table.
2. 5 pieces of polyethylene film were cut in the machine direction (MD) to obtain a dimension of 2″×7″ (width×length in inches), 12 sheets of blank paper were cut to obtain a dimension of 4″×7″, 15 pieces of elastomer strip were cut to obtain a dimension of 0.5″×7″.
3. 2 sets of samples were made: Referring to
FIG. 7
, the 1
st
set placed an elastomeric strip
130
flat on the center of polyethylene film
131
. The polyethylene film
131
was obtained from a HEFTY® CinchSak® tall kitchen bag. The combination of the elastomeric strip
130
and the polyethylene film
131
of
FIG. 7
is referred to as first set structure
132
. The length “L” and the width “W” are indicated in FIG.
7
. Referring to the isometric view of
FIG. 8
, the 2
nd
set placed an elastomer strip
130
a
directly over an elastomeric strip
130
b
. If a top view had been shown, the elastomeric strip
130
b
would not have been visible. The combination of the elastomeric strips
130
a
and
130
b
in
FIG. 8
is referred to as second set structure
134
.
4. Each of the first set structures
132
and the second set structures
134
were conditioned as follows.
5. Referring to
FIG. 9
a
, first set structures
132
were placed between 4″×7″ sheets of paper
142
. The first set structures
132
and the sheets of paper
142
were located between two steel templates
145
a
and
145
b
(4″×7″, templates weight of 4 lbs.). The first set structures
132
and the sheets of paper
142
between the steel templates
145
a
and
145
b
were placed in a temperature-controlled oven for 7 days at 140° F.
6. Referring to
FIG. 9
b
, second set structures
134
were placed between 4″×7″ sheets of paper
142
. The second set structures
134
and the sheets of paper
142
were located between two steel templates
145
c
and
145
d
(4″×7″, templates weight of 4 lbs.). The second set structures
134
and the sheets of paper
142
between the steel templates
145
a
and
145
b
were placed in the temperature-controlled oven for 7 days at 140° F.
7. The first and second set structures
132
and
134
, sheets of papers
142
and steel templates
145
a-d
were removed from the oven and cooled to room temperature. The cooling period was approximately 2 hours. The steel templates
145
a-d
and the sheets of paper
142
were removed from the structures
132
and
134
.
8. Referring to
FIG. 10
a
, the elastomeric strip
130
was manually peeled back (about 2.5″) from the polyethylene film
131
and placed between jaws
150
a
and
150
b
of a tensile tester. The elastomeric strip
130
and the polyethylene film
131
had no slack between the jaws
150
a
and
150
b
. Similarly, in
FIG. 10
b
, the elastomeric strip
130
a
was manually peeled back (about 2.5″) from the elastomeric strip
130
b
and placed between jaws
150
c
and
150
d
of a tensile tester with no slack.
9. The tensile tester was used in determining the peel force. The tensile tester included a set 2-in jaw separation, 20-in/min. cross head speed, 2.5-in jaw travel (jaws travel on y-axis).
10. The peel test was operated by pulling apart the elastomeric strip
130
from the polyethylene strips
131
and the elastomeric strip
130
a
from the elastomeric strip
130
b
. The peak loads (or peel forces) were recorded. The results of the peel force tests for Strips
1
-
5
are shown below in the Table.
TABLE
|
|
Peel Force
Peel Force
|
Strip
Talc
2
Behenamide
3
GMS
4
Erucamide
5
strip-strip
strip-PE film
|
No.
Elastomer
1
(ppm)
(ppm)
(ppm)
(ppm)
(gram)
(gram)
|
|
|
1
Pure yes
0
0
0
0
34.91
25.48
|
2
Pure yes
0
0
4000
600
41.44
32.72
|
3
Pure yes
6000
0
0
600
37.71
34.45
|
4
Pure yes
0
3000
0
0
4.2
5.3
|
5
Pure yes
0
3000
0
600
0
0
|
|
1
The elastomer used was AFFINITY KC8852 (ethylene-octene copolymer).
|
2
The talc used was ABC-5000 PB (50% talc concentrate with a base of LDPE).
|
3
The behenamide used was C
22
H
45
NO from Croda, Inc.
|
4
Glycerol monostearate (GMS).
|
5
The erucamide had a chemical formula of C
21
H
41
CONH
2
and was manufactured by Akzo Nobel Polymer Chemicals, LLC under the name of ARMOSLIP E-N.
|
Referring to the Table, Strips
4
-
5
(comprising at least the elastomer and the behenamide) surprising exhibited a very low value in the strip to strip peel force test and the strip to polyethylene (PE) film peel force test. Strips
1
-
3
, without the behenamide exhibited much higher and undesirable values in both peel force tests. It was surprising that the addition of glycerol monostearate (GMS) and erucamide (Strip
2
) and the addition of talc and erucamide (Strip
3
) not only did not improve the peel force values, but rather increased those values. (Compare peel forces of the elastomer only Strip
1
with Strips
2
and
3
).
While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.
Claims
- 1. A drawtape bag comprising:a pair of pliable thermoplastic body panels joined to each other along a pair of opposing sides and a bottom bridging the opposing sides, at least one of the body panels forming a hem extending along a mouth end disposed opposite the bottom, the hem including one or more drawtape holes; a pliable drawtape housed within the hem, the drawtape including a gathered section, the drawtape being partially exposed by the drawtape holes which allow the drawtape to be pulled therethrough to close the bag and to be used as a handle; and an elastomeric strip connected to the gathered section of the drawtape, the elastomeric strip comprising from about 2,000 to about 20,000 ppm behenamide.
- 2. The drawtape bag of claim 1, wherein the elastomeric strip further comprises erucamide.
- 3. The drawtape bag of claim 1, wherein the elastomeric strip comprises at least about 50 wt. % elastomeric resin.
- 4. The drawtape bag of claim 3, wherein the elastomeric strip comprises at least about 75 wt. % elastomeric resin.
- 5. The drawtape bag of claim 4, wherein the elastomeric strip comprises at least about 90 wt. % elastomeric resin.
- 6. The drawtape bag of claim 5, wherein the elastomeric strip comprises at least about 95 wt. % elastomeric resin.
- 7. The drawtape bag of claim 1, wherein the elastomeric strip comprises from about 2,000 ppm to about 5,000 ppm behenamide.
- 8. The drawtape bag of claim 1, wherein the gathered portion includes one or more loops defining a series of crests and troughs.
- 9. The drawtape bag of claim 1, wherein the elastormeric strip has an elasticity greater than that of the drawtape and a yield strength less than that of the drawtape.
- 10. The drawtape bag of claim 1, wherein the elastomeric strip has a total length less than length of the drawtape.
- 11. The drawtape bag of claim 1, wherein the elastomeric strip is comprised of elastomeric polyethylene and behenamide.
- 12. The drawtape bag of claim 1, wherein the drawtape is comprised of a polymeric material selected from the group consisting of high molecular weight density polyethylenes, medium density polyethylenes, linear low density polyethylenes, low density polyethylenes, polyesters, polystyrenes, polypropylenes and combinations thereof.
- 13. A drawtape bag comnprising:a pair of pliable thermoplastic body panels joined to each other alone a pair of opposing sides and a bottom bridging the opposing sides, the body panels forming respective hems extending along a mouth end disposed opposite the bottom, each of the hems including one or more drawtape holes; a pair of pliable drawtapes housed within the respective hems, each of the drawtapes including a gathered section, each of the drawtapes being partially exposed by the respective drawtape holes which allow the respective drawtape to be pulled therethrough to close the bag and to be used as a handle; and a pair of elastomeric strips connected to the gathered sections of the respective drawtapes, each of the elastomeric strips comprising from about 2,000 to about 20,000 ppm behenamide.
- 14. The drawtape bag of claim 13, wherein the drawtape holes in each of the respective hems are located at the opposing sides, the drawtape holes in the hem on one of the body panels generally coinciding with the respective drawtape holes in the hem on the other of the body panels.
- 15. The drawtape bag of claim 14, wherein the drawtapes are sealed to each other at a pair of drawtape seals coinciding with the drawtape holes.
- 16. The drawtape bag of claim 15, wherein the hems are sealed to the respective body panels along respective hem seals extending along the mouth end of the bag.
- 17. The drawtape bag of claim 16, wherein the hems, the pair of elastomeric strips, and the gathered section of each drawtape are sealed to each other at anchor seals.
- 18. The drawtape bag of claim 13, wherein the pair of pliable drawtapes housed within the respective hems are sealed at opposing side seals of the bags.
- 19. The drawtape bag of claim 13, wherein the pair of elastomeric strips further comprise erucamide.
- 20. The drawtape bag of claim 13, wherein the pair of elastomeric strips comprise at least about 50 wt. % elastomeric resin.
- 21. The drawtape bag of claim 20, wherein the pair of elastomeric strips comprise at least about 75 wt. % elastomeric resin.
- 22. The drawtape bag of claim 21, wherein the pair of elastomeric strips comprise at least about 90 wt. % elastomeric resin.
- 23. The drawtape bag of claim 22, wherein the pair of elastomeric strips comprise at least about 95 wt. % elastomeric resin.
- 24. The drawtape bag of claim 13, wherein the pair of elastomeric strips comprise from about 2,000 ppm to about 5,000 ppm behenamide.
- 25. A drawtape bag comprising:at least one pliable thermoplastic body panel having a top and bottom portion, the at least one body panel forming a hem extending along the top portion opposite of the bottom portion, the hem including one or more drawtape holes; a pliable drawtape housed within the hem, the drawtape including a gathered section, the drawtape being partially exposed by the drawtape holes which allow the drawtape to be pulled therethrough to close the bag and to be used as a handle; and an elastomeric strip connected to the gathered section of the drawtape, the elastomeric strip comprising from about 2,000 to about 20,000 ppm behenamide.
- 26. The drawtape bag of claim 25, wherein the elastomeric strip further comprises erucamide.
- 27. The drawtape bag of claim 25, wherein the elastormeric strip comprises at least about 50 wt. % elastomeric resin.
- 28. The drawtape bag of claim 27, wherein the elastomeric strip comprises at least about 75 wt. % elastomeric resin.
- 29. The drawtape bag of claim 28, wherein the elastomeric strip comprises at least about 90 wt. % elastomeric resin.
- 30. The drawtape bag of claim 29, wherein the elastomeric strip comprises at least about 95 wt. % elastomeric resin.
- 31. The drawtape bag of claim 25, wherein the elastomeric strip comprises from about 2,000 to about 5,000 ppm behenamide.
- 32. An article comprising at least one pliable thermoplastic body panel having a top and bottom portion, the at least one body panel forming a hem extending along the top portion opposite of the bottom portion, and an elastomeric strip comprising from about 2,000 to about 20,000 ppm behenamide, the elastomeric strip housed within the hem.
- 33. The article of claim 32, wherein the hems includes one or more holes to assist in manufacturing the article.
- 34. The article of claim 32, wherein the elastomeric strip further comprises erucamide.
- 35. The article of claim 32, wherein the elastomeric strip comprises at least about 50 wt. % elastomeric resin.
- 36. The article of claim 35, wherein the elastomeric strip comprises at least about 75 wt. % elastomeric resin.
- 37. The article of claim 36, wherein the elastomeric strip comprises at least about 90 wt. % elastomeric resin.
- 38. The article of claim 37, wherein the elastomeric strip comprises at least about 95 wt. % elastomeric resin.
- 39. The article of claim 38, wherein the elastomeric strip comprises from about 2,000 to about 5,000 ppm behenamide.
- 40. The article of claim 32, wherein the bag article is a diaper, shower cap or a laundry bag.
- 41. The drawtape bag of claim 7, wherein the elastomeric strip comprises from about 2,000 ppm to about 4,000 ppm behenamide.
- 42. The drawtape bag of claim 7, wherein the elastomeric strip comprises from about 3,000 ppm to about 5,000 ppm behenamide.
- 43. The drawtape bags of claim 24, wherein the elastomeric strip comprises from about 2,000 ppm to about 4,000 ppm behenamide.
- 44. The drawtape bag of claim 24, wherein the elastomeric strip comprises from about 3,000 ppm to about 5,000 ppm behenamide.
- 45. The drawtape bag of claim 31, wherein the elastomeric strip comprises from about 2,000 ppm to about 4,000 ppm behenamide.
- 46. The drawtape bag of claim 31, wherein the elastomeric strip comprises from about 3,000 ppm to about 5,000 ppm behenamide.
- 47. The article of claim 39, wherein the elastomeric strip comprises from about 2,000 ppm to about 4,000 ppm behenamide.
- 48. The article of claim 39, wherein the elastomeric strip comprises from about 3,000 ppm to about 5,000 ppm behenamide.
US Referenced Citations (144)
Foreign Referenced Citations (1)
Number |
Date |
Country |
WO 9948681 |
Sep 1999 |
WO |