U.S. patent application number 11/013844 was filed with the patent office on 2006-06-29 for moisture proof container.
This patent application is currently assigned to Eastman Kodak Company. Invention is credited to Edgar G. Earnhart, Michael R. McGovern.
Application Number | 20060138146 11/013844 |
Document ID | / |
Family ID | 36610205 |
Filed Date | 2006-06-29 |
United States Patent
Application |
20060138146 |
Kind Code |
A1 |
Earnhart; Edgar G. ; et
al. |
June 29, 2006 |
Moisture proof container
Abstract
A moisture proof container includes a container body having a
flange portion for cooperatively receiving a closure member, the
closure member includes a top portion joining an inner sealing
surface and an outer surface both defining a channel, the channel
being configured to engageably receive the flange portion, and
wherein the outer surface includes spaced-apart retention members
in the channel that provides a means for venting air pressure from
within the container to outside the container.
Inventors: |
Earnhart; Edgar G.; (Hilton,
NY) ; McGovern; Michael R.; (Rochester, NY) |
Correspondence
Address: |
Pamela R. Crocker;Patent Legal Staff
Eastman Kodak Company
343 State Street
Rochester
NY
14650-2201
US
|
Assignee: |
Eastman Kodak Company
|
Family ID: |
36610205 |
Appl. No.: |
11/013844 |
Filed: |
December 16, 2004 |
Current U.S.
Class: |
220/366.1 ;
220/785 |
Current CPC
Class: |
B65D 2543/00518
20130101; B65D 2543/00629 20130101; B65D 2543/00092 20130101; B65D
2543/00407 20130101; B65D 2543/00537 20130101; B65D 2543/00685
20130101; B65D 43/0208 20130101; B65D 2543/00796 20130101; B65D
2543/00555 20130101; B65D 2543/00731 20130101; B65D 2543/00222
20130101; B65D 2543/00296 20130101 |
Class at
Publication: |
220/366.1 ;
220/785 |
International
Class: |
B65D 51/16 20060101
B65D051/16 |
Claims
1. A moisture proof container comprising: a container body having a
flange portion for cooperatively receiving a closure member, said
closure member comprising a top portion joining an inner sealing
surface and an outer surface both defining a channel, said channel
being configured to engageably receive said flange portion, and
wherein said outer surface comprises a plurality of spaced-apart
retention members in said channel that provides a means for venting
air pressure from within the container to outside the
container.
2. The moisture proof container recited in claim 1 wherein said top
portion of said channel further comprises a plurality of
spaced-apart protuberances in said channel for cooperatively
assisting the spaced apart retention members to vent a deleterious
pressure differential exerted about the moisture proof
container.
3. The moisture proof container recited in claim 1 wherein said
retention members of said closure member are configured to resist
separation of said closure member from said body member when said
closure member is exposed to a separation force in a range of
substantially 9 Newtons to 22 Newtons.
4. The moisture proof container recited in claim 1 wherein said
closure member comprises a fatty acid amide.
5. The moisture proof container recited in claim 1 wherein said
container body comprises a fatty acid amide.
6. The moisture proof container recited in claim 1 wherein said
closure member and said container body each comprises a fatty acid
amide.
7. The moisture proof container recited in claim 6 wherein said
fatty acid amide comprises a group consisting of naturally
occurring slip agents of plant origin.
8. The moisture proof container recited in claim 4 wherein said
fatty acid amide is represented in said closure member at a minimum
rate of about 1500 parts per million.
9. The moisture proof container recited in claim 5 wherein said
fatty acid amide is represented in said container body at a minimum
rate of about 1500 parts per million.
10. The moisture proof container recited in claim 6 wherein said
fatty acid amide is represented in each of said closure member and
said container body at a minimum rate of about 1500 parts per
million.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a moisture proof container for a
photographic film cartridge. More particularly, the invention
concerns a combination of a plurality of protuberances and a
plurality of retention members positioned in a channel of the
container cover providing a vent duct to release deleterious gas
pressure incurred during high-altitude shipping.
BACKGROUND OF THE INVENTION
[0002] It is common to use a two-piece plastic container to provide
product integrity (prevention of deleterious moisture and dirt) for
photographic film cartridges. There exists two basic types of
containers in the marketplace as described in U.S. Pat. No.
4,639,386. One type has a closure with a retention feature
cooperating with a groove or grasping ring on the inner diameter
near the open end of the body part. The second type has a closure
with a retention feature cooperating with a bead protrusion or
flange on the exterior of the open end of the outer diameter of the
body part. There is a great deal of art concerned with product
integrity (closure and body fitness) with the first type. Examples
of this prior art are: U.S. Pat. Nos. 4,844,961 and 4,960,626.
However the second type typically exhibits inconsistent closure
retention force and Moisture Vapor Transmission Rate. It is
therefore the object of the present invention to provide a
container for photographic film with a low and consistent Moisture
Vapor Transmission Rate (MVTR) while providing a suitable and
consistent retention force (or fitting strength as disclosed in
U.S. Pat. No. 4,639,386) for a container with a flange on the
exterior of the body part. A suitable closure retention or
separation force is within a force range that is a) acceptable to
consumers to be easily removed and b) resists the rigors of
manufacturing; supply chain; distribution and retail environment to
provide product integrity until it reaches the consumer. In the
case of a container for consumer 35 mm photographic film, this
acceptable force range is typically 9 to 22 Newtons.
[0003] A common means for providing mold release and desired
Moisture Vapor Transmission Rate performance for containers and in
particular those for photographic film is to use lubricant or slip
additives such as fatty acid amides or esters. Fatty acid amide
slip additives however can be detrimental to closure retention
force when the amount approaches a level suitable for maintaining a
low Moisture Vapor Transmission Rate. The present invention
overcomes this stated mutually exclusive condition of achieving the
desired Moisture Vapor Transmission Rate performance while at the
same time achieving a suitable and consistent closure retention
force.
[0004] The present invention provides a container that meets the
above objectives. The closure for the container of the present
invention is composed of a blend of various density polyethylenes
resins along with suitable amounts of additives for improvements
such as color, opacity, appearance, lubricity, Moisture Vapor
Transmission Rate (MVTR), moldability and coloration during
processing. The container body for the container of the present
invention is composed wholly of high-density polyethylene (HDPE)
along with suitable amounts of additives for improvements such as
color, opacity, appearance, lubricity, Moisture Vapor Transmission
Rate (MVTR), moldability and coloration during processing.
[0005] It is common for containers for photographic film to have a
closure comprised wholly of a singular polyethylene resin with a
specific density range plus small amounts (less than 5% by weight
each) of additives for improvements such as color, opacity,
appearance, lubricity, Moisture Vapor Transmission Rate (MVTR),
moldability and coloration during processing. These resins are
commonly identified as low-density polyethylene (LDPE) with density
ranging from 0.910-0.925 g/cm.sup.3, medium-density (MDPE) from
0.926-0.940 g/cm.sup.3, and high-density polyethylene (HDPE) with
density ranging from 0.941-0.965 g/cm.sup.3. Molding grades of
these resins commonly have Melt Flow Rate (MFR) ranging from 5 to
50 g/10 min.. It is known that as the density of polyethylene
increases so does the flexural modulus or bending stiffness.
Likewise it is known that as MFR increases the stiffness of the
bending stiffness decreases. However the interaction of stiffness
to MFR is much less than the interaction of stiffness to density.
The density of polyethylene is to a large part determined by the
extent of branching of the polyethylene molecule, which determines
the extent of crystallinity whereas the MFR is to a large part
determined by the length of the polyethylene chain.
[0006] The flexural modulus for LDPE ranges from about 700 to about
2100 Kg/cm.sup.2, for MDPE from about 2500 to 4500 Kg/cm.sup.2 and
for HDPE from about 6300 to 10500 Kg/cm.sup.2.
[0007] A common type of container for photographic film (as
described in U.S. Pat. No. 4,639,386) has a closure with a sealing
channel forming a sealing surface that interfaces with the inside
of the body part and a skirt circumscribing the outside of the body
part with a continuous retention bead that overlaps a bead or
flange around the outside top of the body. The retention force of
the closure is a function of the stiffness of the closure,
lubricity of the body and/or closure material and the cooperating
geometry of the cover retention bead and the body part flange.
[0008] It is also common in molding of closures for photographic
film containers to use lubricants such as fatty acid amide as a
mold release agent to decrease molding cycle time.
[0009] In the present invention, one way of compensating for the
loss in cover retention or separation force due to the lubricant is
to increase the stiffness of the material by using blends of
various density polyethylene materials. It is noted that a closure
comprised wholly of low-density (LDPE) or high-density polyethylene
(HDPE) is too flexible or too stiff and the closure retention or
separation force is highly variable. It is also noted that the cost
of medium-density polyethylene ( MDPE) material is considerably
higher than a blend of LDPE and HDPE.
SUMMARY OF THE INVENTION
[0010] It is, therefore, an object of this invention to provide a
container for photographic film with a closure of suitable and
consistent retention force.
[0011] Another object of this invention is to provide a container
for photographic film with a low and consistent Moisture Vapor
Transmission Rate (MVTR).
[0012] Another object of this invention is to provide a container
for photographic film and low material cost.
[0013] Accordingly, in one aspect of the invention, a moisture
proof container includes a container body having a flange portion
for cooperatively receiving a closure member. The closure member
has a top portion joining an inner sealing surface and an outer
surface defining a channel. The channel is configured to engageably
receive the flange portion. The outer surface comprises a plurality
of spaced inward facing retention members arranged in the
channel.
[0014] The invention provides a container that meets the above
objects. The closure for this container is composed of a blend of
LDPE and HDPE resins along with suitable amounts additives for
improvements such as color, opacity, appearance, lubricity,
Moisture Vapor Transmission Rate (MVTR), moldability and coloration
during processing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a depiction of the prior art for photographic film
containers as disclosed by Akao et al. (U.S. Pat. No.
4,630,386).
[0016] FIG. 2 is a depiction of the prior art for the fitting
structure for a photographic film container to Type 2 as disclosed
by Akao et al. (U.S. Pat. No. 4,960,626).
[0017] FIG. 3a is a an enlarged cross sectional view of the fitting
structure between removable closure member in the body of the
container.
[0018] FIG. 3b is an isometric partially removed section exposing
the inner structure on the removable closure member.
[0019] FIG. 3c is a cross section of the assembled container.
[0020] FIG. 4a is an enlarged cross section view of the fitment
structure cut through the retention member of the removable
closure.
[0021] FIG. 4b is a partial section view of the fitment structure
showing vent ducts within the fitment structure.
[0022] FIG. 4c is an isometric partially removed section exposing
the inner structure on the removable closure member.
[0023] FIG. 4d is a cross section of the FIG. 4 of the assembled
container.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Referring to FIG. 1: Two types of moisture proof containers
such as those used for photographic film are depicted as previously
disclosed in U.S. Pat. No. 4,630,386 (Akao). Type 1 (plug style) is
composed of a removable closure member 1' and a body portion 2'.
Referring to Type 2 (snap-over style). The moisture proof container
is composed of a removable closure member 1 and body member 2. The
closure member 1 further comprises a receiving channel 3 for
cooperatively receiving a flange portion 4 of body member 2
providing protection from the ingress of moisture and resistance
from inadvertent separation yet allowing easy opening by the
customer for access to the product contained therein. Moisture
ingress is typically measured as an average weight gain per unit
time.
[0025] Referring again to FIG. 1, in the case of photographic film
it is preferable to have a maximum allowed moisture ingress of
about 12 mg/wk. The preferred separating force range is from a
minimum of about 9 newtons to prevent inadvertent separation to a
user-friendly maximum of about 22 newtons.
[0026] Referring to FIG. 2, this figure from U.S. Pat. No.
4,960,626 (Akao et al) depicts an enlargement of the prior art for
the fitting structure of the cover member 1 to the body member 2.
The receiving channel 3 of the cover member 1 is composed of: a top
portion 8 joining a cover member inner sealing surface 6
cooperating with a body member inner sealing surface 5; and a
receiving channel outer surface 9 and a continuous circumferential
retention member 7 protruding axially to cooperate with the
continuous circumferential flange member 4 of the container body
member 2.
[0027] Referring to FIGS. 3a, 3b and 3c, these figures again depict
the prior art for moisture proof containers of the snap-over style
used for protecting photographic film. The cutaway view (FIG. 3b)
of the removable closure member 1 clearly shows the continuous
circumferential nature of the receiving channel 3, the top portion
8, the closure member inner sealing surface 6 and the retention
member 7. Of particular note in FIG. 3a is the primary seal 11,
secondary seal 12 and the tertiary seal 13 between the closure
member 1 and the container. The use of multiple seals to improve
the fitment or moisture proofness of the closure member 1 to the
body member 2 is taught in U.S. Pat. No. 4,844,961.
[0028] Referring again to FIGS. 3a, 3b and 3c, a common problem
with moisture proof containers of the snap-over type is that the
closure member 1 has a nigh rate of blowing off when subjected to a
drop of environmental pressure such as that associated with air
shipping at high altitudes. The redundant seals while being
beneficial to preventing moisture ingress prevent the venting of
higher pressure inside the container than that of a low-pressure
environment. A high-pressure differential induces removal forces on
inside of closure member 1 to lift axially from body member 2.
However the tertiary seal 13 formed by the continuous
circumferential retention member 7 and flange portion 4 of body
member 2 prevents venting of the higher-pressure gas inside the
container. The forces induced on the inside of the closure member 1
from the higher differential pressure is often higher than the
maximum user friendly removal force of about 22 newtons for which
the structure of the container was designed.
[0029] Referring to FIGS. 4a, 4b, 4c and 4d, these figures depict
the present invention and the preferred embodiment. The present
invention has a cover member 1 with a receiving channel 3 composed
of: a top portion 8 joining a closure member sealing surface 6 and
a receiving channel outer surface 9. A plurality of spaced
retention members 7 are directed radially from the outer surface 9,
and a plurality of spaced protuberances 10 are positioned on the
top portion 8.
[0030] Referring again to FIG. 4b, the protuberances 10 and
retention members 7 are spaced in a manner forming at least one
vent duct 14 from the primary seal 11 to the exterior of the
container. The vent duct 14 allows venting of higher-pressure gas,
such as those incurred in lower pressure environments encountered
in high altitude shipping, from inside of the container 15 (see
FIG. 4d). This equilibration of pressure prevents the
pressure-induced forces on the inside of the closure member 1 from
exceeding the maximum user-friendly removal force of about 22
newtons for which the structure of the container closure member 1
and body member 2 were designed.
[0031] Referring again to FIGS. 4a and 4d, the container closure
member 1 and body member 2 are commonly composed of olefin based
resins such as polyethylene or polypropylene selected for their
inherent resistance to moisture transmission. A lubricant such as
fatty acid amide is commonly used as an additive to the materials
composing the closure member 1 and/or the body member 2 to improve
fitment for moisture proofing, affect the cover member 1 removal
force, and affect extraction during forming by means of injection
molding, thermoforming or compression forming. The preferred
additive are selected from a group of naturally occurring fatty
acid amide slip agents represented at a rate from about 1500 parts
per million (0.15 weight percent) to about 4000 parts per million
(0.40 weight percent). A representation rate lower than about 1500
parts per million resulted in deformation of the retention members
4. A representation rate higher than about 4000 parts per million
resulted in a deleterious residue on the product contained inside.
Further. it is noted that moisture proofing (i.e, MVTR) is
acceptable with only the primary seal 11 required thru the slip
agent additive range of about 1500 to 4000 parts per million.
[0032] Referring again to FIGS. 4a, 4b, 4c and 4d, these figures
depict the preferred embodiment relative to the material
composition of the present invention. The closure member 1 is
composed of a blend of high-density polyethylene (HDPE) and
low-density polyethylene (LDPE) resins (with a Young's Modulus of
about 2140 Kg/cm.sup.2) along with suitable amounts of color and
slip agent additives. The HDPE resin is represented at a rate of
about 15 to 20 weight percent. The LDPE resin is represented at a
rate of about 75 to 80 weight percent. The fatty acid amide slip
agent is represented at a nominal rate of about 0.2 weight percent.
The remainder is composed of coloring and opacifying agents (if
required) such as titanium dioxide (TiO2) and carbon black. The
blend representation of HDPE and LDPE provides the specific
stiffness needed for the structure of the closure member 1 to
satisfy the maximum user-friendly opening force requirement of
about 22 Newtons. The required specific stiffness could also be
obtained by blending amounts of linear low-density polyethylene
(LLDPE), polypropylene or other suitable low moisture transmission
thermoplastic resins.
[0033] The invention has been described in detail with particular
reference to certain preferred embodiments thereof. It will be
understood that variations and modifications can be effected within
the spirit and scope of the invention.
Parts List
[0034] 1 Closure member with receiving channel [0035] 1' Closure
member [0036] 2 Container body having flange portion [0037] 2'
Container body with plug receiver [0038] 3 Receiving channel [0039]
4 Flange member [0040] 5 Body member inner sealing surface [0041] 6
Closure member inner sealing surface [0042] 7 Retention member
[0043] 8 Top portion [0044] 9 Receiving channel outer surface
[0045] 10 Protuberances [0046] 11 Primary Seal [0047] 12 Secondary
Seal [0048] 13 Tertiary Seal [0049] 14 Vent duct [0050] 15
Container
* * * * *