Information
-
Patent Grant
-
6230912
-
Patent Number
6,230,912
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Date Filed
Thursday, August 12, 199925 years ago
-
Date Issued
Tuesday, May 15, 200123 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 215 381
- 215 382
- 215 383
- 220 671
- 220 672
- D09 541
- D09 543
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International Classifications
-
Abstract
A plastic bottle comprises a label panel portion comprising a plurality of ribs extending annularly about the perimeter thereof and lands located between each rib for accepting a label thereon, wherein the ribs are configured to render the label panel substantially rigid and capable of enduring pasteurization without subjecting the lands to substantial alteration or misalignment. A pasteurizable bottle having a label panel onto which a label may be evenly secured is thus provided.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to plastic containers; particularly to plastic containers designed to hold liquids under pressure during pasteurization or other thermal treatment.
2. Background Art
Bottles of various configurations and materials have long been employed for the distribution of liquids by the beverage industry. Although the beverage industry traditionally employed glass containers to deliver liquid beverages to customers, that industry has recently embraced the use of plastic bottles due to the relative cost advantages and durability of plastics. For reasons of efficiency and to lower production costs, the plastic container industry has embraced the conventional technique of blow molding plastic containers from plastic preforms. Polyethylene terephthalate (“PET”) or polypropylene (“PP”) are typically used to construct plastic containers because of, among other reasons, the ability to reclaim and recycle containers constructed therefrom. A barrier layer constructed, for example from ethylene vinyl alcohol (“EVOH”), is sometimes employed with the PET or PP to inhibit the migration of gases such as oxygen and carbon dioxide as well as moisture into or out of, the container.
Although plastic has proven more durable than glass in many aspects, plastic containers may be subject to deformation, in instances in which glass was not, due to the relative strength of thicker glass bottles over the thinner plastic bottles. Sanitation requires that beverages be at least partially sterilized prior to reaching the consumer. Typically this is accomplished by elevating the beverage to a predetermined temperature for a specified period of time in order to kill all objectionable organisms without major chemical alteration of the beverage. The two currently accepted methods for accomplishing such sterilization are hot-filling and pasteurization. Hot-filling entails heating the beverage to the required temperature for the required period of time prior to bottling the beverage. The bottles are then filled and sealed while the beverage remains at an elevated temperature sufficient to assure that living objectionable organisms on the container surfaces are rendered harmless. As the beverage cools from the sterilizing temperature, the internal pressure of the bottle drops and creates a pressure differential with the surrounding environment which is sustained until the bottle is opened by the consumer. Thus, hot-filled bottles often deform inwardly as a result of the pressure differential. This deformation is often referred to as “paneling.” Alternatively, the beverage may be sterilized after filling, often referred to in the industry as “pasteurization” and will likewise be so referenced herein. Pasteurization entails filling each bottle with unsterilized beverage and sealing the bottle. The bottle and its contents are then raised to the desired temperature for the desired period of time in order to kill all objectionable organisms without major chemical alteration of the beverage. Because the beverage is sealed prior to pasteurization, no objectionable organism from the surrounding environment may infiltrate the beverage. The sterility of the beverage is thus guaranteed. The internal pressure of the bottle is substantially elevated with respect to that of the surrounding environment as the pasteurization process heats the beverage in the sealed bottle. This pressure differential may result in outward deformation of the bottle. Although the internal pressure of the bottle typically returns to the pre-pasteurization level, the bottle may retain some deformation experienced during pasteurization.
Prior plastic bottle configurations have attempted to overcome the deformation caused by hot-filling and pasteurization by simply increasing the overall wall thickness of the bottle. The resulting costs and manufacturing difficulties experienced with these configurations rendered them commercially unacceptable. Other bottle configurations have employed various ribs or panels about the bottle in an attempt to elevate its resistance to deformation. However, these configurations created difficulties with properly placing a label on the bottle and the complicated nature of these bottle configurations often rendered the bottle prohibitively costly.
Specific configurations of the bottle base have been constructed to prevent base deformation which may cause the bottle to be unstable when rested upright on its base. One such base configuration can be found in co-pending U.S. patent application Ser. No. 09/172,345 which is hereby incorporated herein by reference in its entirety.
Bottles intended to undergo hot-filling rather than pasteurization are usually designed to absorb the pressure differential that is created by the cooling of the beverage subsequent to sealing the bottle. This pressure absorption is often accomplished by placing “vacuum panels” in the sidewall of a hot-fill bottle. Thus, aesthetic features of hot-fill bottle configurations anticipate, and are designed to accommodate, change resulting from the sterilization process.
Conversely, bottles intended for pasteurization are not designed to anticipate aesthetic changes resulting from the sterilization process. Rather, because the bottle deformation that results from the internal pressure created by pasteurization subsides once the beverage cools, bottles intended for pasteurization may be molded with the same aesthetic features that will be viewed by the final consumers. Thus, permanent deformation is especially undesirable for bottles intended to undergo pasteurization rather than hot-filling. Permanent deformation resulting from pasteurization is not anticipated. Thus, deformation of pasteurizable bottles should be prevented or, at least, maintained within the elastic zone of deformation for the material from which the bottle is constructed.
SUMMARY OF THE INVENTION
It is one of the principal objectives of the present invention to provide a plastic bottle having a high resistance to deformation due to hot-filling or sterilization.
It is another objective of the present invention to provide a plastic bottle comprising annular ribs which provide resistance to both longitudinal and radial bottle deformation.
It is another objective of the present invention to provide a plastic bottle comprising annular ribs which provide resistance to deformation without requiring excessive wall thickness.
It is another objective of the present invention to provide a plastic bottle comprising annular ribs which have a predetermined depth to width ratio to provide resistance to both longitudinal and radial bottle deformation.
It is another objective of the present invention to provide a plastic bottle that is cost effective and will resist both longitudinal and radial deformation.
It is still another objective of the present invention to provide a plastic bottle having a high resistance to longitudinal and radial deformation and is capable of being blow molded from a standard preform.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1
is a side elevational view of a container according to the present invention.
FIG. 2
is a cross sectional view of a single annular rib of the container shown in FIG.
1
.
FIG. 3
is a bottom elevational view of the base of the container shown in FIG.
1
.
DETAILED DESCRIPTION OF THE DRAWINGS
A container according to the present invention is depicted in
FIG. 1
in the form of a bottle
10
having a top end
12
with a threaded finish
14
for receiving a thread-on cap (not shown) to seal the bottle
10
after filling with a desired product. A rounded neck portion
16
integrally extends downward and outward from the top end
12
widening to form integrally with an annular groove
18
. Annular groove
18
then extends integrally into a body portion
20
of the bottle
10
wherein the body portion
20
comprises a cylindrical wall
22
having a label panel portion
24
with a plurality of annular ribs
26
therein. A single rib
26
is depicted in cross-section in
FIG. 2
separated from the remainder of the bottle
10
. A base
28
of the bottle
10
extends integrally from, and closes the bottom end of, the body portion
20
. The base
28
is depicted in
FIG. 3
dissected from the remaining portions of the bottle
10
. Preferably, the bottle
10
is formed as an integral unit by blow molding from a standard preform using conventional blow molding techniques.
As depicted in
FIG. 1
, the plurality of annular ribs
26
are each separated one from another by an annular land
30
. Each annular rib
26
, as depicted in
FIG. 2
, comprises a pair of opposing outer radii
32
, each of which comprises an outer end
34
and an inner end
36
. The outer end
34
of each outer radius
32
is contiguous with an adjacent annular land
30
and each outer radius
32
extends inward of the annular land
30
. Each annular rib
26
further comprises a pair of opposing straight walls
38
each having an outer end
40
and an inner end
42
. The outer end
40
of each straight wall
38
is contiguous with an adjacent one of the outer radius inner ends
36
as depicted in FIG.
2
. Each annular rib
26
further comprises a pair of opposing inner radii
44
each having an outer end
46
and an inner end
48
wherein each straight wall inner end
42
is contiguous with an adjacent inner radii outer end
46
as depicted in FIG.
2
. Each annular rib
26
further comprises a root wall
50
extending contiguously between the opposing inner radii inner ends
48
to close off the rib
26
.
Each rib
26
extends annularly about the cylindrical wall
22
and is oriented substantially perpendicular to a central longitudinal axis
52
of the bottle
10
. Furthermore, each land
30
and each root wall
50
are oriented substantially parallel to the bottle central longitudinal axis
52
.
As depicted in
FIG. 1
, and discussed above, the plurality ribs
26
are located within the label panel portion
24
of the bottle
10
. The label panel portion
24
is provided with two annular beads
54
for label panel protection, one located at each of the upper and lower ends of the label panel portion
24
to bolster its resistance to radial deformation (often referred to as hoop strain). The label panel portion is configured to provide an area in which the beverage manufacturer may place a label to communicate the contents of the bottle, information required by government regulations and any desired marketing information or materials which may be required to impart the desired image to a consumer. It is important to assure that the label panel provides an even surface that will support a label and will not subject the label to excess damage prior to reaching the ultimate consumer so that the message and image presented by the label is not adversely effected. Bottle configurations that damage a label or the image intended to be imparted thereby, are commercially unacceptable. Therefore, the label panel portion
24
of the present bottle
10
designed to assure that the lands
30
provide an even surface to support a label, even after being subjected to the rigors of pasteurization
It has been found that the strength of the label panel section
24
may be optimized by providing the ribs with an average depth to width ratio in the approximate range of 1.0:1.0-1.1:1.0. Deformation of the bottle
10
will typically occur either longitudinally along the central longitudinal axis
52
due to longitudinal stresses or radially of the bottle
10
due to radial stresses. Radial stresses resulting from pasteurization are commonly referred to as hoop stress. By dimensioning the ribs
26
in the above range of ratios, the ribs are configured to withstand nearly equal amounts of longitudinal stress and radial stress such that any resulting deformation will likewise be nearly equal. Increasing the length E of the root wall
50
or increasing the radius of curvature of the inner radii
44
to lower the depth to width ratio would expose the ribs
26
to excessive deformation in the form of buckling (inward for hot-filling and outward for pasteurization). The resulting excessive deformation may enter the zone of plastic deformation of the material from which the bottle
10
is constructed and thus result in permanent deformation permanently altering the aesthetic appearance of the bottle
10
regardless of whether the deformation resulted from hot-filling or pasteurization. Lowering the depth to width ratio of the ribs
26
is therefore undesirable.
Conversely, shortening the length E of the root wall
50
or decreasing the radius of curvature of the inner radii
44
to increase the depth to width ratio would result in difficulties of blow molding a parison around the rib portion of the mold as is known in the art. Difficulties would also arise in obtaining a proper release of the bottle from the mold as is also known in the art.
It has also been found that the strength of the label panel portion
24
may be optimized by providing the ribs
26
with an average land
30
width to total rib
26
width (“total rib width” being measured between the outer radii outer ends
34
of a single rib
26
) ratio in the range of 1.09:1.0-1.30:1.0. Thus, the length B of the label panel
24
and the size of the ribs
26
will determine the number of ribs
26
in the label panel
24
.
Constructing the plurality of ribs
26
and the interspersed lands
30
of the bottle
10
within the above strictures will provide the label panel
24
with a sufficient resistance to deformation such that the lands
30
will remain substantially radially aligned and provide an area onto which a label may be secured. This label area is not substantially altered by the pasteurization process. Moreover, the land width to total rib width ratio discussed above provides ample support to a label to ensure its integrity and allow the information thereon to be easily viewed by consumers without the portions of the label extending between the lands
30
(and thus across the ribs) becoming substantially damages or altered due to normal wear and tear to which a beverage bottle will be subjected.
For example, a bottle according to the present invention was reheat stretch blow molded from PET having a diameter A of 2.832 inches at each land
30
(and thus a circumference of 8.897 inches), a panel portion height B of 7.683 inches, a rib depth C (as measured from the exterior of the land
30
to the exterior of the root wall
50
) of 0.120 inches, a rib width D (as measured between the opposing inner radius outer ends
46
) of 0.112 inches, a root wall
50
having a length E of 0.050 inches, the inner radii
44
having a radius of curvature of 0.031 inches and running for ninety degrees (90°), the outer radii
32
having a radius of curvature of 0.060 inches and running for ninety degrees (90°) with the straight wall
38
extending at an angle of fifteen degrees (15°) from perpendicular to the central longitudinal axis
52
. In this configuration, the depth to width ratio is 1.071:1. The lands
30
are 0.27 inches long, the total rib width is 0.2475 inches and the ribs
26
have a thickness F of 0.015-0.019 inches. The bottle was filled with water and pasteurized at 165° F. for a timer period in the range of ten (10) to twenty (20) minutes and then left to cool. The bottle exhibited no visible deformation once cooled.
From the foregoing description, it will be apparent that the plastic container of the present invention has a number of advantages, some of which have been described above and others of which are inherent in the bottle
10
of the present invention. Also, it will be understood that modifications can be made to the plastic container of the present invention without departing from the teachings of the invention. Accordingly the scope of the invention is only to be limited as necessitated by the accompanying claims.
Claims
- 1. A plastic bottle configured to substantially resist deformation comprising a cylindrical wall defining a longitudinal axis having a plurality of annular ribs extending about the perimeter thereof, wherein the annular ribs each comprise a pair of opposing outer radii, a pair of substantially straight wall portions, one extending from each outer radii to a position inward of the bottle cylindrical wall, each annular rib further comprising a width and a depth and the ratio of the depth to width of each annular rib is approximately between 1.0:1.0 and 1.1:1.0.
- 2. The bottle of claim 1, the substantially straight wall portion defining an angle of substantially fifteen degrees from perpendicular to the longitudinal axis.
- 3. The bottle of claim 1 wherein each annular rib further comprises a pair of opposing inner radii, one extending from each substantially straight wall portion, and a root wall extending between the opposing inner radii.
- 4. The bottle of claim 3 wherein the root wall is substantially straight.
- 5. The bottle of claim 1 wherein the bottle cylindrical wall comprises a land located between each pair of adjacent annular ribs.
- 6. The bottle of claim 5, each land having a width and the ratio of the width of each land an adjacent one of the plurality of annular ribs being between 1.09:1.0 and 1.3:1.0.
- 7. The bottle of claim 6 wherein each land is substantially straight.
- 8. The bottle of claim 7, the annular ribs and lands comprising a label panel and the lands providing a surface to which a label may be substantially adhered.
- 9. The bottle of claim 1 being constructed of PET and the cylindrical wall having a thickness of between 0.015 and 0.019 inches.
- 10. A plastic bottle configured to substantially resist deformation from pasteurization, the bottle comprising a cylindrical wall defining a longitudinal axis and having a plurality of ribs extending annularly about the longitudinal axis, each rib defining a width and a depth, the ratio of the depth to width of each annular rib being approximately between 1.0:1.0 and 1.1:1.0, and each of the plurality of ribs being separated from an adjacent one of the plurality of ribs by a land defining a land width, the ratio of the land width to rib width being between 1.09:1.0 and 1.3:1.0.
- 11. The bottle of claim 10, the annular ribs each comprising a substantially straight wall portion extending inward of said bottle cylindrical wall.
- 12. The bottle of claim 11, the substantially straight wall portion defining an angle of substantially fifteen degrees from perpendicular to the longitudinal axis.
- 13. The bottle of claim 11, each annular rib further comprising a pair of opposing outer radii, one extending between an adjacent outer land and one of the substantially straight wall portions, a pair of opposing inner radii, one extending from each substantially straight wall portion, and a root wall extending between the opposing inner radii.
- 14. The bottle of claim 13 wherein the root wall is substantially straight.
- 15. The bottle of claim 10 wherein each land is substantially parallel to the longitudinal axis.
- 16. The bottle of claim 15, the annular ribs and lands comprising a label panel and the lands providing a surface to which a label may be substantially adhered.
- 17. The bottle of claim 10 being constructed of PET and the cylindrical wall having a thickness of between 0.015 and 0.019 inches.
- 18. A plastic bottle configured to substantially resist deformation from pasteurization, comprising a cylindrical wall defining a longitudinal axis and having a plurality of annular ribs, each adjacent pair of annular ribs being separated by a land,each annular rib comprising an outer radius extending from each adjacent land, a substantially straight wall extending from each outer radius and directed substantially inward of the outer cylindrical wall, an inner radius extending from each substantially straight wall, and a root wall extending between the inner radii, each annular rib defining a width, and a depth, the ratio of the depth to width of each annular rib being approximately between 1.0:1.0 and 1.1:1.0, and each land defining a land width, the ratio of the land width to rib width being between 1.09:1.0 and 1.3:1.0.
- 19. The bottle of claim 18, the substantially straight wall defining an angle of substantially fifteen degrees from perpendicular to the longitudinal axis.
- 20. The bottle of claim 18 being constructed of PET and the cylindrical wall having a thickness of substantially between 0.015 and 0.019 inches.
US Referenced Citations (47)
Foreign Referenced Citations (1)
Number |
Date |
Country |
189987 |
May 1957 |
AU |