U.S. patent application number 12/581952 was filed with the patent office on 2010-04-22 for digital printing plastic containers with improved adhesion and recyclability.
This patent application is currently assigned to PLASTIPAK PACKAGING, INC.. Invention is credited to Edward V. Morgan, Ronald L. Uptergrove.
Application Number | 20100096386 12/581952 |
Document ID | / |
Family ID | 42107822 |
Filed Date | 2010-04-22 |
United States Patent
Application |
20100096386 |
Kind Code |
A1 |
Uptergrove; Ronald L. ; et
al. |
April 22, 2010 |
DIGITAL PRINTING PLASTIC CONTAINERS WITH IMPROVED ADHESION AND
RECYCLABILITY
Abstract
A container having an external surface with a digital image
printed thereon by droplets of ink is provided. The digital image
includes a base coat and a secondary coat that is applied to the
base coat. In an embodiment, the digital image adheres to the
container with an acceptable or sufficient adhesion score and the
image is removable using conventional recycling processes. Methods
for digitally printing containers and facilitating recycling are
also disclosed.
Inventors: |
Uptergrove; Ronald L.;
(Northville, MI) ; Morgan; Edward V.; (Northville,
MI) |
Correspondence
Address: |
DYKEMA GOSSETT PLLC
39577 WOODWARD AVENUE, SUITE 300
BLOOMFIELD HILLS
MI
48304-5086
US
|
Assignee: |
PLASTIPAK PACKAGING, INC.
Plymouth
MI
|
Family ID: |
42107822 |
Appl. No.: |
12/581952 |
Filed: |
October 20, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61106860 |
Oct 20, 2008 |
|
|
|
Current U.S.
Class: |
220/62.11 ;
220/601; 220/604 |
Current CPC
Class: |
Y02W 30/80 20150501;
B65D 2203/00 20130101; B41M 5/0082 20130101; B41M 7/0009 20130101;
B65D 2565/385 20130101; B41M 7/0081 20130101; Y02W 30/807 20150501;
B65D 23/0814 20130101; B41M 5/0017 20130101 |
Class at
Publication: |
220/62.11 ;
220/604; 220/601 |
International
Class: |
B65D 1/40 20060101
B65D001/40 |
Claims
1. A recyclable plastic container comprising: an external surface
with a digital image printed thereon by droplets of ink, the
digital image having an adhesion score of at least 6.0.
2. The container of claim 1, wherein the digital image includes: a
base coat including a plurality of cured base coat ink droplets,
and a secondary coat including a plurality of cured secondary coat
ink droplets, the secondary coat being applied to at least a
portion of the base coat.
3. The container of claim 1, wherein the printed digital image is
configured to be substantially separated from the remainder of the
container during a recycling process.
4. The container of claim 1, wherein the digital image is
configured to, at a minimum, pass a tape test and a simulated
shipment test.
5. The container of claim 4, wherein the tape test includes a
modified 3M #610 tape test.
6. The container of claim 1, wherein the digital image has an
adhesion score of 6.0 or 7.0.
7. The container of claim 2, wherein, at the time the secondary
coat is applied to the base coat, the temperature differential
between the base coat and the secondary coat is less than about
10.degree. F.
8. The container of claim 1, wherein the container includes a base
portion, a sidewall portion, a shoulder portion, and a neck
portion, and the neck portion includes a dispensing opening.
9. The container of claim 2, wherein the base coat includes white
or colorless portions.
10. The container of claim 2, wherein one or more adjacent
secondary coat ink droplets overlap or are intermixed.
11. The container of claim 2, wherein the secondary coat ink
droplets are colored.
12. The container of claim 11, wherein the colors include one or
more of the following colors: cyan, magenta, and yellow.
13. The container of claim 2, wherein the secondary coat ink
droplets vary in diameter.
14. The container of claim 13, wherein the diameters of the
secondary coat ink droplets are within the range of about 10
microns to about 200 microns.
15. The container of claim 1, wherein the container is comprised of
one or more of the following materials: polyethylene, polyethylene
terephthalate, high density polyethylene, and polypropylene.
16. The container of claim 1, wherein the container is a
multi-layer container.
17. The container of claim 1, wherein the container includes
recycled plastic material.
18. The container of claim 17, wherein the outermost layer of the
container has a recycled content, the recycled content being 20% or
less.
19. The container of claim 2, wherein the base coat and secondary
coat ink droplets are UV cured.
20. A recyclable plastic container comprising: an external surface
with a digital image printed thereon by droplets of ink, the
digital image including: a base coat including a plurality of cured
base coat ink droplets, and a secondary coat including a plurality
of cured secondary coat ink droplets, the secondary coat being
applied to at least a portion of the base coat; wherein the digital
image is configured to pass a modified 3M #610 tape test and is
configured to be substantially separated from the remainder of the
container during a recycling process.
21. The container of claim 21, wherein the digital image is
configured to fail a standard 3M #810 tape test.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. provisional
patent application Ser. No. 61/106,860, filed Oct. 20, 2008, which
is incorporated by reference in its entirety as if fully set forth
herein.
TECHNICAL FIELD
[0002] The present invention relates generally to plastic
containers having digital images printed thereon, particularly
containers having improved adhesion and recycling characteristics
and methods for digitally printing containers and facilitating
recycling.
BACKGROUND
[0003] Product manufacturers commonly impose labeling standards on
plastic containers that are intended to hold their products.
Various tests, including a number of industry standardized tests,
have been used to measure and evaluate the quality of label
application. Some standard test methods that have been employed
include, by way of example and without limitation, ASTM
International test designations D 3359-08 (Standard Test Methods
for Measuring Adhesion by Tape Test); D 5264-98 (Standard Practice
for Abrasion Resistance of Printed Materials by the Sutherland
Rubber Tester); and F 1842-02 (Standard Test Method for Determining
Ink or Coating Adhesions on Plastic Substrates for Membrane Switch
Applications). Product manufacturers often define testing
requirements and resultant scores that should be met for a labeled
product to be deemed acceptable.
[0004] Container manufacturers have recently produced containers
with digitally printed labels that are of a sufficient definition
and quality to compete with and potentially replace prior
conventional labeling techniques. Examples of such printing
techniques are described in U.S. patent application Ser. No.
11/562,655, which is incorporated herein by reference. However, for
many applications, it is desirable to utilize standards for
providing, measuring, and assessing printed images that may serve
as labels.
[0005] Potential challenges arise introducing containers with
digitally printed labels into conventional container recycling
processes. There is a clear trend amongst container manufacturers,
brand owners, end users, and governmental entities to improve and
increase container recycling efforts. Consequently, it would be
desirable to provide industry-acceptable containers that are
sufficiently compatible with the current recycling infrastructure
and processes, or that provide sufficient incentive and/or volumes
to effectuate industry-wide changes. At least initially, it would
be desirable to provide digitally printed containers that are
recyclable using current industry standard processes--i.e.,
processes that commonly include caustic high-temperature washing
and grinding. As such, there is a desire for digitally printed
plastic containers that have digital images that adhere to the
container without quality issues throughout its useful life, but
are readily removable during plastic recycling processes.
SUMMARY
[0006] A plastic container is disclosed that has an external
surface with a digital image printed thereon by droplets of ink.
The digital image includes a base coat and a secondary coat that is
applied to the base coat. Embodiments of the invention disclose
containers having improved adhesion and/or recycling
characteristics. In an embodiment, the digital image adheres to the
plastic container and the digital image has an acceptable or
"passing" adhesion score (which for some scoring systems is a score
of 6.0 or greater). Methods for digitally printing containers and
facilitating recycling are also disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments of the invention will now be described, by way
of example, with reference to the accompanying drawings,
wherein:
[0008] FIG. 1 generally illustrates a side view of a portion of a
container with a digital image printed thereon;
[0009] FIG. 2 is general representation of a quality review
table/matrix that may be used to evaluate the acceptability of a
printed image on a container.
DETAILED DESCRIPTION
[0010] Reference will now be made in detail to embodiments of the
present invention, examples of which are described herein and
illustrated in the accompanying drawings. While the invention will
be described in conjunction with embodiments, it will be understood
that they are not intended to limit the invention to these
embodiments. On the contrary, the invention is intended to cover
alternatives, modifications and equivalents, which may be included
within the spirit and scope of the invention as defined by the
appended claims.
[0011] A portion of a surface 10 of a container with a printed
digital image 20 is generally illustrated in FIG. 1. The digital
image 20 includes a base coat 30 that may be comprised of a
plurality of base coat ink droplets 32, and a secondary coat 40
that is comprised of a plurality of secondary coat ink droplets
42.
[0012] The base coat 30 may be comprised of a material that serves
to improve the application of ink droplets and/or provides a visual
characteristic. For embodiments, the base coat 30 may comprise
white and/or colorless portions. In embodiments of the invention,
at least a first base coat 30 is applied to a surface of a
container at a first time t.sub.1 and at a first temperature
T.sub.1. The temperature T.sub.1 will be in the range of
temperatures that are appropriate for application of the associated
base coat. In an embodiment, the base coat 30 may be ultraviolet
(UV) curable, and further may be cured prior to an application of a
secondary coat.
[0013] The secondary coat 40 may be comprised of a plurality of
secondary coat ink droplets 42 that are distributed on at least a
portion of the base coat 30. A plurality of secondary coat ink
droplets 42 may collectively form a part of an application pattern
which, in turn, may form all or a portion of a digital image.
Furthermore, as generally illustrated in FIG. 1, portions of one or
more adjacent secondary coat ink droplets 42 may overlap or
intermix with each other. The secondary coat 40, and the
constituent secondary coat ink droplets 42, may comprise various
known colors, including without limitation, primary printing colors
such as cyan, magenta, and yellow. Further, controlling the
overlapping of or combinations of certain colors in certain areas
can provide additional "process" colors. Additionally, the
secondary coat ink droplets 42 may be curable. For example, UV
curable secondary coat ink droplets may comprise all or a portion
of the intended digital image. Depending upon the application, the
secondary coat ink droplets can vary in diameter, which can range,
for instance, from about 10 microns to about 200 microns. The
secondary coat 40 may be applied to a surface 10 of a container at
a second time t.sub.2 and at a second temperature T.sub.2, wherein
the second temperature T.sub.2 at which the secondary coat 40 is
applied is typically less than the first temperature T.sub.1 at
which the base coat 30 is applied.
[0014] In embodiments of the invention, the time between
application of a base coat and the application of a secondary coat
(e.g., t.sub.2 minus t.sub.1) may be reduced--for example, to as
little as ten seconds or less. For some embodiments, the
application time differential will be within two to six seconds.
Moreover, in embodiments, the application temperature differential
between the temperature at which the base coat 30 is applied and
the temperature at which a secondary coat 40 is applied to a
portion of the base coat 30, i.e., T.sub.1 minus T.sub.2, may be
controlled to be equal to or less than about 10.degree. F. For some
embodiments, the application temperature differential will be
within about 5.degree. F. to about 10.degree. F. Moreover, for some
applications, it may be desirable to modify the temperatures
associated with the application of the base coat 30 and the
secondary coat 40 so that the respective application temperatures
are closer together--i.e., so that the temperature differential
between the applied coats is reduced or minimized. This can be
accomplished, for instance, by (a) lowering/decreasing T.sub.1, (b)
raising/increasing T.sub.2, or (c) a combination of (a) and (b).
Such aforementioned time and/or temperature control with respect to
the base coat and secondary coat can provide for better adhesion of
the resulting printed digital image with respect to the
container.
[0015] It is noted that in addition to time and temperature,
irradiance is a factor that can also affect the effective cure rate
for a printed image. That is, with certain times (e.g., t.sub.1 and
t.sub.2) and temperatures (e.g., T.sub.1 and T.sub.2), there may be
an associated irradiance--i.e., .epsilon..sub.1 and
.epsilon..sub.2. For example, in embodiments a base coat may be
cured at irradiance .epsilon..sub.1, and an associated secondary
coat may be cured at irradiance .epsilon..sub.2. Further, in
embodiments, the effective cure rate--which may be based on a
combination of time, temperature, and irradiance--the irradiance
may generally be provided by the following equation:
Irradiance(.epsilon.)=(d.phi./dA) [0016] where, .phi.=irradiant
flux (measured in watts), and [0017] A=area (cm.sup.2) For example,
without limitation, the range of irradiance for some embodiments
will be between about 0.1 watts/cm.sup.2 and about 10.0
watts/cm.sup.2.
[0018] The containers (which includes bottles) associated with the
present invention are comprised of a plastic material (e.g., PET,
HDPE, PP, PE, etc.). The containers may be mono-layer or
multi-layer containers, and can be formed using various
conventional forming techniques including, without limitation, blow
molding, thermoforming, etc. In an embodiment, the outermost
layer/surface is comprised of a virgin plastic material. Although,
it is noted that containers in accordance with the teachings of the
invention may include some percentage of recycled content,
including a small percentage (e.g., 20% or less) in the outer layer
of the container.
[0019] For some applications, such as where a curable ink (e.g., a
UV-curable ink) is used, the relevant coat or ink may be cured
after each respective print station. For example, without
limitation, an embodiment of a process may, at least in part,
comprise: application of base coat; cure step; application of
secondary coat; and cure step. Alternatively, also by way of
example and without limitation, the process may, at least in part,
comprise: application of base coat; cure step; application of base
coat; cure step; application of secondary coat, and cure step.
Moreover, for embodiments of the invention, it can be desirable for
the production/subsequent handling rate of containers/bottles to
match or substantially match the flow/processing rates of the
associated printing machine(s).
[0020] Further, it has been found that the quality of printed
digital images may be, at least in part, controlled and/or improved
through one or more of the following techniques:
[0021] (a) selection and/or calibration of ink sets;
[0022] (b) control of substrate (i.e., container surface)
temperature; and/or
[0023] (c) timing control.
[0024] With respect to the selection and/or calibration of ink
sets, this is accomplished, at least in part, by the selection
and/or calibration of the inks comprising the base and secondary
coats. It has been discovered that the inks used can be selected to
provide desired time and/or temperature characteristics, including
relative to one another in combination. For example, selection of
certain inks having given viscosities can exhibit or provide
certain desired temperature related effects.
[0025] With regard to the control of the substrate (i.e., container
surface) temperature, the temperature of a relevant portion of a
sidewall (or other portion of a container) can be treated or
controlled to some measure. For example a given portion of the
container can be pre-treated. Such pre-treatment can be facilitated
using various known techniques that may include, without
limitation, flame, corona, and plasma treatment. However, the
invention is not limited to those specific pre-treatment
techniques.
[0026] With respect to timing control, the time associate with the
movement of containers, for instance through a production machine,
as well as the timing of the applications of the base coat and/or
secondary coat, can be controlled. It can be desirable for the
production/subsequent handling rate of containers/bottles to match
or substantially match the flow/processing rates of the associated
printing machine(s).
[0027] The present invention also includes a system for assessing
or evaluating the "acceptability," such as the commercial
acceptability, of a container having a digitally printed
image--such as a digitally printed label. That is, for embodiments
of the invention, the system for assessing or evaluating can
provide an "adhesion score." FIG. 2 generally represents a quality
review table/matrix that can be used to assess or evaluate the
acceptability of a printed image on a container. As generally
shown, the Y-axis may involve numbers associated with an overall
pass-or-fail score. In the illustrated embodiment, numbers 1
through 5 indicate that the containers are not acceptable, while
numbers 6 through 9 indicate that the associated containers are
acceptable. It is important to note that while a score of at least
a 6 will "pass" as acceptable with respect to the instant
table/matrix, the invention is not limited to the specific
table/matrix shown and, alternatively, more scores could be
provided for and/or the passing score could be raised or lowered as
desired or necessary. A plurality of tests--which may include
various standard tests, including those previously noted--are
represented in the columns provided on the X-axis. For example,
without limitation, Test 1 may include a "Sutherland Rub Test,"
Test 2 may comprise a "3M #610 Tape Test," Test 3 may include a
"Simulated Ship Test," and Test 4 may comprise a "3M #810 Tape
Test." As generally shown in the table, various pass-or-fail
designations may be represented on the table in connection with
each noted Test. With respect to several of the aforementioned
"standard" tests, the tests may be modified as appropriate for use
in connection with a printed image as opposed to a traditionally
applied label. For instance, with various "tape" tests, which may
follow the ASTM D 3359-08 standards, the tests associated with the
table/matrix may or may not involve the cutting of the digital
image portion with a cutting tool prior to applying a pressure
sensitive tape. That is, in an embodiment, "Test 2" may involve a
"modified" 3M #610 Tape Test in so far as the portion of the
digital image portion of a container that is subjected to testing
may not be cross-cut or otherwise separated from the container.
Moreover, with the table set forth in FIG. 2, an indication of a
"pass," with respect to tape tests directly practicing the modified
ASTM standard (i.e., the test does not involve
cross-cutting/separation) would generally be represented by any
removed portions being no larger than 2.0 mm.sup.2. With respect to
tape tests directly practicing the ASTM standard, an indication of
"pass" would generally be a classification "4B" or "5B" (under the
ASTM FIG. 1 Classification of Adhesion Test Results), or would
involve less than 5% of the printed area removed.
[0028] In an embodiment, it is desirable to provide a container
with a printed digital image that, at a minimum, passes a modified
3M #610 tape test and is nonetheless "recyclable." A digital image
that is printed on a container is considered to be "recyclable" if
it would achieve less then a "4B" classification (i.e., 5% of more
of the area is removed) employing an ASTM D 3359 standard #810 tape
test. A container with a digital image that passes Test 2 (modified
3M #610 Tape Test) and Test 3 (Simulated Ship Test), yet fails Test
4 (3M #810 Tape Test), would achieve an adhesion score of either
6.0 or 7.0. Such a container with a printed image having an
adhesion score of 6.0 or 7.0 is commercially suitable for shipment
(i.e., passing a Simulated Ship Test) while providing an adhesion
associated with the printed image that is sufficient for
normal/intended use but is favorably separable for subsequent
recycling. Stated differently, the adhesion associated with the
configured digital image is sufficiently strong for intended use
but does not impede separation during recycling.
[0029] With respect to such a table/matrix, each test may be
conducted on a adequate (e.g., statistically significant or
representative) sampling of containers. After all tests are
completed, results may be tabulated and entered into the
table/matrix, to provide an "adhesion" score. The associated score
outcomes can then be correlated.
[0030] Among other things, the present invention can provide for
improved recyclability. For example, without limitation, containers
with digitally printed images (which may be formed by cured
UV-curable ink) can be conveniently removed in connection with
conventional plastic recycling processes. Industry standard
recycling process of plastic containers conventionally include
grinding containers into granulated plastic flakes, subjecting
these flakes to a high-heat caustic wash process, drying the
cleaned flakes, sorting, and extruding into resin pellets for
resale. With embodiments of the invention, digital image on the
container may remain with the resin flakes after the grinding
process, the digital image will be substantially separated from the
resin flakes during the high-heat caustic wash process, thereby not
contaminating the clean resin flakes to be formed into resin
pellets.
[0031] The foregoing descriptions of specific embodiments of the
present invention have been presented for purposes of illustration
and description. They are not intended to be exhaustive or to limit
the invention to the precise forms disclosed, and various
modifications and variations are possible in light of the above
teaching. The embodiments were chosen and described in order to
explain the principles of the invention and its practical
application, to thereby enable others skilled in the art to utilize
the invention and various embodiments with various modifications as
are suited to the particular use contemplated. It is intended that
the scope of the invention be defined by the claims appended hereto
and their equivalents.
* * * * *