U.S. patent application number 15/582853 was filed with the patent office on 2017-08-17 for time validation indicator.
This patent application is currently assigned to Performance Indicator, LLC. The applicant listed for this patent is Performance Indicator, LLC. Invention is credited to Satish AGRAWAL, Louis CINCOTTA, Clifford PARKER.
Application Number | 20170235280 15/582853 |
Document ID | / |
Family ID | 52018118 |
Filed Date | 2017-08-17 |
United States Patent
Application |
20170235280 |
Kind Code |
A1 |
CINCOTTA; Louis ; et
al. |
August 17, 2017 |
Time Validation Indicator
Abstract
A time validation indicator is disclosed comprising at least a
receiving layer and an activating layer. The receiving layer
comprises at least one or more masking colorants and one or more
deactivators that cause and maintain the one or more masking
colorants in an initial colored state. The activating layer
comprises at least one or more migratory activators that migrate
into the receiving layer upon at least a portion of the receiving
layer being placed in contact with at least a portion of the
activating layer to initiate a predetermined time period. The
migration of the one or more migratory activators into the
receiving layer causes at least a portion of the one or more
masking colorants to advance to a final colorless state resulting
in a visual color change of the receiving layer that indicates the
predetermined time period has elapsed. Also disclosed are methods
for creating and using the inventive time validation indicator.
Inventors: |
CINCOTTA; Louis; (Andover,
MA) ; PARKER; Clifford; (New Ipswich, NH) ;
AGRAWAL; Satish; (Concord, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Performance Indicator, LLC |
Lowell |
MA |
US |
|
|
Assignee: |
Performance Indicator, LLC
Lowell
MA
|
Family ID: |
52018118 |
Appl. No.: |
15/582853 |
Filed: |
May 1, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15059866 |
Mar 3, 2016 |
9645552 |
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15582853 |
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13916617 |
Jun 13, 2013 |
9310311 |
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15059866 |
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Current U.S.
Class: |
116/201 |
Current CPC
Class: |
Y10T 156/10 20150115;
C09D 11/50 20130101; G04F 1/02 20130101; G04F 13/02 20130101; G01N
31/229 20130101; G04F 1/00 20130101; G01N 21/78 20130101 |
International
Class: |
G04F 1/02 20060101
G04F001/02; C09D 11/50 20060101 C09D011/50; G01N 31/22 20060101
G01N031/22; G01N 21/78 20060101 G01N021/78; G04F 13/02 20060101
G04F013/02 |
Claims
1-35. (canceled)
36. A time validation indicator, said time validation indicator
comprising: a receiving layer that comprises: (i) a masking
colorant; and (ii) a deactivator that causes and maintain said
masking colorant in an initial colored state, wherein the
deactivator is an electron accepting compound; an activating layer
that comprises a migratory activator that migrates into the
receiving layer upon at least a portion of the receiving layer
being placed in contact with at least a portion of the activating
layer to initiate a predetermined time period, and a timing layer
that comprises a material that at least partially retards the rate
of migration of the one or more migratory activators into the
receiving layer, wherein the migration of the migratory activator
into the receiving layer causes at least a portion of the masking
colorant to advance to a final colorless state resulting in a
visual color change of the receiving layer that indicates that the
predetermined time period has elapsed.
37. The time validation indicator of claim 1, wherein the timing
layer comprises one or more of polyacrylic, polyurethane,
polycarbonate, polyester, and fluorinated polymer.
38. The time validation indicator of claim 1, wherein the timing
layer comprises a static colorant.
39. The time validation indicator of claim 1, wherein the timing
layer comprises an adhesive.
40. The time validation indicator of claim 1, wherein the timing
layer is disposed between the receiving layer and the activation
layer.
41. The time validation indicator of claim 1, wherein the masking
colorant is a leuco dye.
42. The time validation indicator of claim 1, wherein the receiving
layer further comprises a polymer that functions together with the
deactivator to cause and maintain the masking colorant to be in an
initial colored state.
43. The time validation indicator of claim 1, wherein at least one
of the receiving layer and the activating layer further comprises a
plasticizer that aids in the migration of the migratory activator
into the receiving layer.
44. The time validation indicator of claim 1, wherein at least one
of the receiving layer and the activating layer further comprises
at least one of a dispersant, a thickener, a wetting agent, and a
defoamer.
45. The time validation indicator of claim 1, wherein at least one
of the receiving layer and the activating layer further comprise a
static colorant.
46. The time validation indicator of claim 1, further comprising a
colorant layer that comprises a static colorant.
47. The time validation indicator of claim 1, further comprising a
base substrate, wherein the base substrate comprises an indicia
area that is capable of being visually observed upon at least a
portion of the masking colorant of the receiving layer being
partially or fully in the final colorless state.
48. A method for indicating a predetermined time period has
elapsed, said method comprising: providing a time validation
indicator that comprises: a receiving layer that comprising: (i) a
masking colorant; and (ii) a deactivator that causes and maintain
said masking colorant in an initial colored state, wherein the
deactivator is an electron accepting compound; and an activating
layer that comprises a migratory activator that migrates into the
receiving layer upon at least a portion of the receiving layer
being placed in contact with at least a portion of the activating
layer to initiate a predetermined time period, and a timing layer
that comprises a material that at least partially retards the rate
of migration of the one or more migratory activators into the
receiving layer; positioning the receiving layer, the activating
layer, and the timing layer such that the timing layer is disposed
between the receiving layer and the activation layer and at least a
portion of the receiving layer and at least a portion of the
activating layer are in contact with at least a portion of the
timing layer to initiate the predetermined time period; and
detecting the visual color change of the receiving layer that
indicates that the predetermined time period has elapsed.
49. The method of claim 13, further comprising applying the time
validation indicator to at least a portion of a surface of an
object.
50. The method of claim 13, wherein the timing layer comprises one
or more of polyacrylic, polyurethane, polycarbonate, polyester, and
fluorinated polymer.
51. The method of claim 13, wherein the timing layer comprises a
static colorant.
52. The method of claim 13, wherein the masking colorant is a leuco
dye.
53. The method of claim 13, wherein the receiving layer further
comprises a polymer that functions together with the deactivator to
cause and maintain the masking colorant to be in an initial colored
state.
54. A time validation indicator comprising: a receiving layer that
comprises: (i) one or more masking colorants; and (ii) one or more
deactivators that cause and maintain said one or more masking
colorants in an initial colored state, wherein the one or more
deactivators are one or more electron accepting compounds; and an
activating layer that comprises one or more migratory activators
that migrate into said receiving layer upon at least a portion of
said receiving layer being placed in contact with at least a
portion of said activating layer to initiate a predetermined time
period.
Description
BACKGROUND OF THE INVENTION
[0001] These teachings relate generally to time validation
indicators, and more particularly, to the preparation and use of
time validation indicators that are easily adaptable for various
time intervals of expiration, and hence capable of providing
digital and distinct indication of expiration of a predetermined
time period.
[0002] Various indicators have been utilized in a number of
different applications for indicating when a specific time period
has elapsed. For example, time-temperature indicators have been
used in areas such as pharmaceutical and food industries for
indicating when perishable materials, i.e. materials having a
measurable shelf-life, reach a predetermined expiration date and
need to be discarded. Other examples of areas for which time
indicators have been utilized include general inventory management,
monitoring projects and activities, security badges, and a host of
other time dependent events.
[0003] Currently, the majority of known time indicators provide,
after activation, a visual indication of a predetermined period of
time. Many of these known time indicators provide this visual
indication by way of color change through the use of dye migration
or dye diffusion. For example, U.S. Pat. Nos. 4,903,254, 5,822,280,
and 7,139,226 employ the use of colored indicators that migrate,
once activated, through opaque films to indicate the passage of
time. In these systems, the final colored state of the indicator is
generated in or below the opaque layer and then migrates through
this layer to become visible. Alternative efforts, such as those
cited U.S. Pat. Nos. 4,212,153, 4,248,597, and 4,643,122 describe
similar approaches that include the migration of an acid/base or
solvent within a laminated structure containing a pH indicator,
such that a color change results following activation due to a
subsequent change in pH. Other known time indicators provide a
color change by way of chemical reactions, such as those cited in
U.S. Pat. Nos. 3,018,611 and 4,812,053 which employ an oxygen
reactive material that reacts with oxygen upon exposure and
produces a visual color change. Furthermore, U.S. Pat. No.
5,085,802 describes an additional color change reaction suitable
for providing a visual indication of a predetermined period of
time. This color change reaction involves the generation of an
acid/base "in-situ" through the use of enzymes in the presence of a
pH indicator, thereby producing a subsequent color change with a
change in pH.
[0004] A general problem that exists with approaches based on dye
migration or dye diffusion, as well as chemical reactions, to
provide a visual indication of a predetermined time period is the
gradual nature of the color change over the time period, thereby
making it difficult for the user to ascertain exactly when the
designated end point is reached. A common approach in addressing
the foregoing problem is by additionally incorporating the use of a
control color strip or target strip adjacent to the time indicator
in order to make visual comparisons as time progresses. However,
the use of color or target strips add to the cost of making and
employing the time indicators, as well as still having the
possibility of user error in determining when the predetermined
time period has elapsed. Time indicators that rely solely on the
migration of dyes, solvents, reactants, etc. cannot escape the grey
scale problem since it is an inherent aspect of diffusion kinetics.
Another drawback includes the inability to use such time indicators
for long time periods, i.e. month(s) or year(s). Therefore, there
is a continued need to develop reliable, visual time indicator
systems and devices which can be used for a variety of different
applications and predetermined time periods.
[0005] There have been further attempts in providing a visual
indication of a predetermined period of time with the migration of
jelly or liquids through a wick material to indicate the lapse or
elapse of time, such as those cited in U.S. Pat. Nos. 3,954,011 and
3,962,920. These technologies impregnate the wicking material with
an indicator and the progress of a fluid along the wick material is
visibly indicated and used to measure or determine a lapse or
elapse of time. One drawback to such approaches is that they
generally require a reservoir of fluid that is needed in order to
visually indicate or measure a passage of time. Such a requirement
increases the cost of utilizing these types of approaches, as well
as limits their applicability, etc.
[0006] Given the drawbacks of the current time indicators utilized
to provide a visual indicator of a predetermined period of time,
there is, therefore, a need for a time validation indicator that is
capable of providing a digital (step-wise) and distinct indication
when a predetermined time period has elapsed. In providing a
digital and distinct indication, such a time validation indicator
affords a more reliable and accurate visual indication than that of
the prior art. It is also desirable, therefore, to provide a time
validation indicator that is easily adaptable for use in
determining expiration of a wide variety of time intervals, i.e.
short or longer periods of time, resulting in more applicability.
Furthermore, it also desirable to provide a time validation
indicator that is inexpensive and simpler to construct and to
employ than that of the prior art.
BRIEF SUMMARY OF THE INVENTION
[0007] The present teachings provide for a time validation
indicator comprising a receiving layer and an activating layer. The
receiving layer comprises one or more masking colorants and one or
more deactivators that cause and maintain the one or more masking
colorants in an initial colored state. In some instances, the
receiving layer may further comprise one or more polymers that
function together with the one or more deactivators to cause and
maintain the one or more masking colorants to be in the initial
colored state. The activating layer comprises one or more migratory
activators that migrate into the receiving layer upon at least a
portion of the receiving layer being placed in contact with at
least a portion of the activating layer to initiate a predetermined
time period. The migration of the one or more migratory activators
into the receiving layer causes at least a portion of the one or
more masking colorants to advance to a final colorless state
resulting in a visual color change of the receiving layer that
indicates the predetermined time period has elapsed. In some
instances, the one or more masking colorants may be one or more
leuco dyes. In other instances, the one or more deactivators may be
one or more electron accepting compounds. In further instances, the
one or more migratory activators may be one or more polyoxygenated
compounds. In certain constructions, at least one of the receiving
layer or the activating layer may further comprise one or more
plasticizers that aid in the migration of the one or more migratory
activators into the receiving layer. In other constructions, at
least one of the receiving layer or the activating layer may also
comprise at least one of one or more dispersants, one or more
thickeners, one or more wetting agents, or one or more defoamers.
In other aspects, at least one of the receiving layer or the
activating layer may further comprise one or more adhesive
materials that bond together at least a portion of the receiving
layer to at least a portion of the activating layer when placed in
contact. In further instances, at least one of the activating layer
or the receiving layer may also comprise one or more static
colorants that are capable of being visually observed upon at least
a portion of the one or more masking colorants of the receiving
layer being partially or fully in the final colorless state. The
time validation indicator of the present teachings may additionally
comprise an adhesive layer that bonds together at least a portion
of the receiving layer to at least a portion of the activating
layer when placed in contact. The time validation indicator of the
present teachings may also comprise a colorant layer that comprises
one or more static colorants that are capable of being visually
observed upon at least a portion of the one or more masking
colorants of the receiving layer being partially or fully in the
final colorless state. The time validation indicator of the present
teachings may further comprise a timing layer that at least
partially retards the rate of migration of the one or more
migratory activators into the receiving layer. The time validation
indicator of the present teachings may optionally comprise one or
more base substrates. In some instances, one of the one or more
base substrates may include an indicia area that is capable of
being visually observed upon at least a portion of the one or more
masking colorants of the receiving layer being partially or fully
in the final colorless state.
[0008] The present teachings also provide for a method for
fabricating a time validation indicator. The method of the present
teachings comprises forming a receiving layer that comprises one or
more masking colorants and one or more deactivators that cause and
maintain the one or more masking colorants to be in an initial
colored state. In some instances, the receiving layer may further
comprise one or more polymers that function together with the one
or more deactivators to cause and maintain the one or more masking
colorants to be in the initial colored state. The method of the
present teachings further comprises forming an activating layer
that comprises one or more migratory activators that migrate into
the receiving layer upon at least a portion of the receiving layer
being placed in contact with at least a portion of the activating
layer to initiate a predetermined time period. The method of the
present teachings further comprises placing at least a portion of
the receiving layer in contact with at least a portion of the
activating layer to initiate the predetermined time period and the
migration of the one or more migratory activators into the
receiving layer. The migration of the one or more migratory
activators into the receiving layer causes at least a portion of
the one or more masking colorants to advance to a final colorless
state resulting in a visual color change of the receiving layer
that indicates the predetermined time period has elapsed. In other
instances, at least one of the activating layer or the receiving
layer may further comprise one or more static colorants that are
capable of being visually observed upon at least a portion of the
one or more masking colorants of the receiving layer being
partially or fully in the final colorless state. The method of the
present teachings may further comprise applying an adhesive means
that bonds together at least a portion of the receiving layer to at
least a portion of the activating layer when placed in contact. The
applying of the adhesive means may include rendering an adhesive
layer onto at least a portion of at least one of the receiving
layer or the activating layer. Alternatively, or in addition,
applying the adhesive means may comprise incorporating one or more
adhesive materials into at least one of the receiving layer or the
activating layer. The method of the present teachings may also
include rendering a colorant layer disposed onto at least a portion
of the activating layer, in which the colorant layer comprises one
or more static colorants that are capable of being visually
observed upon at least a portion of the one or more masking
colorants of the receiving layer being partially or fully in the
final colorless state. The method of the present teachings, may
further comprise rendering a colorant layer disposed onto at least
a portion of the receiving layer, in which the colorant layer
comprises one or more static colorants that are capable of being
visually observed upon at least a portion of the one or more
masking colorants of the receiving layer being partially or fully
in the final colorless state. In some instances, the method of the
present teachings may also comprise applying a timing layer
disposed onto at least a portion of the activating layer or, in the
alternative, disposed onto at least a portion of the receiving
layer. The timing layer at least partially retards the rate of
migration of the one or more migratory activators into the
receiving layer. The method of the present teachings may
additionally comprise rendering one or more base substrates, in
which at least a portion of at least one of the activating layer or
receiving layer is disposed onto the one or more base substrates.
In some instances, one of the one or more base substrates may
include an indicia area that is capable of being visually observed
upon at least a portion of the one or more masking colorants of the
receiving layer being partially or fully in the final colorless
state.
[0009] The present teachings further provide for a method for
indicating a predetermined time period has elapsed. The method of
the present teachings comprises providing a time validation
indicator that comprises a receiving layer and an activating layer.
The receiving layer comprises one or more masking colorants and one
or more deactivators that cause and maintain the one or more
masking colorants to be in an initial colored state. The receiving
layer may further comprise one or more polymers that function
together with the one or more deactivators to cause and maintain
the one or more masking colorants to be in the initial colored
state. The activating layer comprises one or more migratory
activators that migrate into the receiving layer to cause at least
a portion of the one or more masking colorants to advance to a
final colorless state that results in a visual color change of the
receiving layer. In some aspects, at least one of the activating
layer or the receiving layer may further comprise one or more
static colorants that are capable of being visually observed upon
at least a portion of the one or more masking colorants of the
receiving layer being partially or fully in the final colorless
state. The time validation indicator may further comprise an
adhesive means that bonds together at least a portion of the
receiving layer with at least a portion of the activating layer
when placed in contact. The time validation indicator may also
comprise a colorant layer having one or more static colorants that
are capable of being visually observed upon at least a portion of
the one or more masking colorants of the receiving layer being
partially or fully in the final colorless state. The time
validation indicator may optionally comprise a timing layer that at
least partially retards the rate of migration of the one or more
migratory activators into the receiving layer. The time validation
indicator may also comprise one or more base substrates. In some
instances, one of the one or more base substrates may include an
indicia area that is capable of being visually observed upon at
least a portion of the one or more masking colorants of the
receiving layer being partially or fully in the final colorless
state. The method of the present teachings further comprises
placing at least a portion of the receiving layer in contact with
at least a portion of the activating layer to initiate the
predetermined time period and the migration of the one or more
migratory activators into the receiving layer. The method of the
present teachings further comprises detecting the visual color
change of the receiving layer that indicates the predetermined time
period has elapsed. The method of the present teachings may also
comprise applying the time validation indicator to at least a
portion of a surface of an object.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present teachings are illustratively shown and described
in reference to the accompany drawings, in which
[0011] FIG. 1 is a schematic drawing of a time validation indicator
according to one aspect of these teachings;
[0012] FIG. 2 is an example of a chemical structure and mechanism
of coloration of the one or more masking colorants in the instance
where the one or more masking colorants are a type of fluoran
dye;
[0013] FIG. 3 is an example of a chemical structure and mechanism
of coloration of the one or more masking colorants in the instance
where the one or more masking colorants are a type of phthalide
dye;
[0014] FIG. 4 is a schematic drawing of a time validation indicator
according to a second aspect of these teachings;
[0015] FIG. 5 is a schematic drawing of a time validation indicator
according to another aspect of these teachings;
[0016] FIG. 6 is a schematic drawing of a time validation indicator
according to a further aspect of these teachings;
[0017] FIG. 7 is a schematic drawing of a time validation indicator
according to another aspect of these teachings;
[0018] FIG. 8 is a graph illustrating the affect different
concentrations of one or more deactivators have on the timing
period of the present invention;
[0019] FIG. 9 is a graph illustrating the affect different
concentrations of one or more migratory activators have on the
timing period of the present invention;
[0020] FIG. 10 is a graph illustrating the affect various types of
one or more migratory activators have on the timing period of the
present invention;
[0021] FIG. 11 is a graph illustrating the affect different
concentrations of one or more plasticizers within the activating
layer have on the timing period of the present invention; and
[0022] FIG. 12 is a graph illustrating the affect different
concentrations of one or more plasticizers within the receiving
layer and activating layer have on the timing period of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present teachings are directed to the creation and use
of time validation indicators that can provide a digital and
distinct visual indication of expiration of a predetermined time
period with the use of at least a receiving layer and an activating
layer that, when placed in contact with each other to initiate the
predetermined time period, produce a visual color change indicating
the predetermined time period has elapsed.
[0024] For a better understanding of the disclosure, the following
terms are herein defined:
[0025] A "liquid carrier medium" is a liquid that acts as a carrier
for material(s) distributed in a solid state and/or substantially
dissolved therein.
[0026] As used herein, a "formulation" is a liquid carrier medium,
as defined above, comprising one or more polymers either dissolved
in and/or distributed in a solid state within the liquid carrier
medium. The formulation may additionally comprise one or more
materials that are distributed in a solid state and/or
substantially dissolved therein.
[0027] A "layer" as used herein refers to a film resulting from the
application and substantial drying of a formulation, or in some
instances by way of extrusion, injection molding, etc.
[0028] The following disclosure describes time validation
indicators, as well as the methods and materials for creating such
indicators. These indicators possess a number of superior
qualities, such as ability to provide digital and distinct
indication of a predetermined time period, as well as allow for
easy manipulation of the timing period such that these indicators
can be utilized for various predetermined time periods, e.g. short,
i.e. hour(s), day(s), or week(s), or long, i.e. month(s) or
year(s).
[0029] Generally speaking, the time validation indicator, according
to the present teachings, employs the use of at least a receiving
layer that comprises one or more masking colorants and one or more
deactivators, and an activating layer that comprises one or more
migratory activators that migrate into the receiving layer upon at
least a portion of the receiving layer being placed in contact with
at least a portion of the activating layer to initiate the
predetermined time period. This migration of the one or more
migratory activators causes a visual color change of the receiving
layer, thereby indicating the predetermined time period has
elapsed. It should be noted, that the orientation or ordering of
the layers of the time validation indicator is not limited by the
schematic drawings which are generally presented herein and for
illustrative purposes only. More specifically, the top most layer
of the time validation indicator that is viewed by the end user to
observe the visual color change may in some instances be that of
the activating layer, whereas in other instances may be that of the
receiving layer.
[0030] Turning now to FIG. 1, is a schematic illustration of one
aspect of the time validation indicator, according to the present
teachings. In this example, the time validation indicator (2)
comprises a receiving layer (4) and an activating layer (6). The
receiving layer (4) comprises one or more masking colorants and one
or more deactivators in which the one or more deactivators cause
and maintain the one or more masking colorants in an initial
colored state, prior to the initiation of the predetermined time
period. The activating layer (6) comprises one or more migratory
activators which migrate into the receiving layer (4) when at least
a portion of the receiving layer (4) is placed in contact with at
least a portion of the activating layer (6). Once the receiving
layer (4) and activating layer (6) are placed in contact, the
predetermined time period and the migration of the one or more
migratory activators into that of the receiving layer (4) are
initiated, thereby causing at least a portion of the one or more
masking colorants to begin to advance to a final colorless state.
As the one or more masking colorants advance to the final colorless
state over the predetermined time period, a visual color change of
the receiving layer (4) occurs. Once at least a portion of the one
or more masking colorants reach the final colorless state, the
resulting visual color change of the receiving layer (4) indicates
that the predetermined time period has elapsed.
[0031] Prior to the activation of the time validation indicator,
i.e. prior to placing at least a portion of the receiving layer in
contact with at least a portion of the activating layer to begin
the predetermined time period, the one or more masking colorants in
the receiving layer are in an initial colored state by way of the
presence of the one or more deactivators. The one or more
deactivators, e.g. electron-accepting compounds such as, for
example, Lewis acids, clays, or proton-donating compounds, cause
and maintain, prior to activation, the one or more masking
colorants to be an initial colored state by interacting, chemically
or physically, with that of the one or more masking colorants
within the receiving layer. In some instances, the receiving layer
may further comprise additional one or more polymers that function
together with the one or more deactivators to aid in causing and
maintaining the one or more masking colorants to be in the initial
colored state. In such instances, these additional one or more
polymers along with the polymer(s) of the receiving layer may be
the same, or in the alternative the one or more polymers may be
different than that of the polymer(s) of the receiving layer.
[0032] Various colorants may be used as the one or more masking
colorants within the receiving layer of the present invention, e.g.
dyes. Suitable dyes include, but are not limited to, leuco dyes
which are capable of reversibly forming a colored, carbonium ion
species such as those depicted in FIGS. 2 and 3. Examples of
suitable leuco dyes include, but are not limited to, spiropyrans,
benzopyrans, fluoran dyes such as
2'-anilino-3'-methyl-6'-(dibutylamino) fluoran, illustrated in FIG.
2, phthalide dyes such as crystal violet lactone, illustrated in
FIG. 3, triarylmethane phthalides, diarylmethane phthalides, or
monoheterocyclic substituted phthalides, or those or similar to
those described in U.S. patent application Ser. No. 13/178,766,
which is incorporated by reference herein in its entirety. It
should be noted that the foregoing chromogenic compounds are given
for purposes of illustration since any chromogenic compound which
is capable of interacting with electron accepting compound(s) may
be employed as the one or more masking colorants of the receiving
layer. Given that the human eye cannot discriminate optical density
changes that occur at high initial density, having, prior to
activation of the time validation indicator, the one or more
masking colorants in an initial colored state and upon activation,
advance to a final colorless state allows for the time validation
indicator to provide a more digital color change. This is because
the optical density of the receiving layer has to be lowered
significantly before the color change of such layer can be
perceived. As a result, such an approach, i.e. having the one or
more masking colorants advance from an initial colored state to a
final colorless state, is contrary to the general approach utilized
in prior time indicators.
[0033] In the instances where the one or more masking colorants are
one or more leuco dyes, it is generally believed that the color
forming reaction of the leuco dye(s) occur through the interaction
of the electron donating colorless leuco dye(s) with one or more
electron accepting compound(s) to produce the reversible opening of
the lactone ring(s), see e.g. FIGS. 2 and 3, yielding the
resonance-stabilized cationic leuco dye(s) in the initial colored
state. The properties of the color development system, i.e. the one
or more leuco dyes and one or more electron-accepting compounds,
are a complex subject of investigation and it has become obvious
that many parameters can influence the kinetics of the ring opening
reaction of the leuco dye(s).
[0034] As described in more detail below, a large number of
environmental factors can influence whether the one or more leuco
dyes, when utilized, are in the opened colored form or the closed
colorless form. As a result, this provides great flexibility in
adjusting the time validation indicator of the present teachings by
way of manipulating the formulation of both the receiving layer
and/or the activating layer.
[0035] Although not intended to be bound by theory it is believed
that in the instance where the one or more masking colorants are
that of one or more leuco dyes and the one or more deactivators are
one or more electron accepting compounds, the one or more
deactivators function as complexing agents or hydrogen bonding
agents with the opened form of the leuco dye(s) to generate a
conjugated system. The class of leuco dyes that are represented by
photochromic dyes such as, the spirooxazines, have been well
studied and certain aspects of their characteristics can be related
to the leuco fluoran and phthalide lactone type dyes useful in the
present invention. Specifically, the environmental conditions that
influence the transformation from colorless to colored via opening
of the lactone ring appear to be similar for both classes of
lactone type dyes. Like the Spirooxazines, the triarylmethane and
fluoran leuco dyes are comprised of two aromatic nearly planar
moieties. These moieties are linked by a tetrahedral sp.sup.3
spiro-carbon which insulates the two .pi.-electron systems from
conjugation. Due to the lack of conjugation, the Spiro type
compounds are pale yellow or colorless. However, conditions which
favor ring opening and conversion of the spiro compound to a
sp.sup.2 hybridization result in the aromatic groups aligning its
.pi.-orbitals with each other and forming a conjugated system which
is now able to absorb visible light, becoming a highly colored
cationic species, see e.g. FIGS. 2 and 3,
[0036] Spirooxazines have also been studied in different types of
polymers, e.g. cellulose acetate butyrate, polyurethanes, PVC,
epoxies, acrylics, polyester, etc., in an attempt to modify their
sensitivity to ring opening. These studies show that the ring
opening reaction is highly sensitive to the viscosity of their
medium. For example, the lowering of the glass transition
temperature (Tg) of the host matrix will improve the ease of the
transition from colorless to colored and the reverse. The viscosity
of the surrounding matrix has a large effect on the opening of the
ring system of the one or more leuco dyes because of the size of
the fragments that must rotate relative to each other to achieve
the sp.sup.2 state. This was elegantly demonstrated in "The Generic
Enhancement of Photochromic Dye Switching Speeds in a Rigid Polymer
Matrix," by R. A. Evans et. al., Nature Materials, Vol. 4 (2005),
pp. 249-253, in which covalent photochromic-oligomer conjugates
were created and consisting of a leuco dye and a soft, low-Tg
oligomer such as, poly(dimethylsiloxane) or poly(ethyleneglycol),
to protect the leuco dye from a harsh switching environment, i.e.
from a rigid or high-Tg polymer. The leuco dye is protected by the
spontaneous coiling of its attached low-viscosity oligomer, which
insulates the leuco dye from the surrounding high-Tg,
high-viscosity bulk matrix, as described and disclosed in U.S. Pat.
No. 7,807,075 which is incorporated by reference herein in its
entirety. The leuco dye can be thought of as being permanently
lubricated and protected at the molecular level to allow facile
ring opening and closing. Furthermore, in "Reversibly
Coloring/Decoloring Reaction of Leuco Dye Controlled by Long-Chain
Molecule," by Horiguchi et. al, Thin Solid Films, Vol. 516 (2008),
pp. 2591-94, has shown that the reversible opening and closing of a
similar leuco dye to that of the one or more leuco dyes that may be
used in the present invention is regulated by the structural
organization of the leuco dye and a long chain electron accepting
compound. This structural change shows the occurrence of
intercalation and deintercalation of the leuco dye in the
reversible coloring process. It is believed that in instances where
the one or more masking colorants of the present invention are that
of one or more leuco dyes, a similar mechanism is at least
partially responsible for the color effect that occurs with the
migration of the one or more migratory activators into the
receiving layer. It has been shown that the cationic, open form of
the leuco dye(s) is not only sensitive to the polarity of solvents,
but that protic solvents hydrogen bond to the initial colored state
of the leuco dye(s) and thus stabilize it. Therefore with the
appropriate choice of the polymer(s) of the receiving layer, i.e.
the use of a polymer(s) that will aid in the opening of the one or
more leuco dyes through, for example, its hydrogen bonding capacity
or polarity, in combination with that of the one or more
deactivators, it is possible to cause and maintain the one or more
Leuco dyes in an initial colored state, prior to activation of the
time validation indicator.
[0037] Once the time validation indicator is activated, i.e.
placing at least a portion of the receiving layer in contact with
at least a portion of the activating layer, the predetermined time
is initiated and the one or more migratory activators begin to
migrate into the receiving layer causing at least a portion of the
one or more masking colorants to advance to a final colorless
state, by way of interfering/interacting with at least the complex
or hydrogen bonding of the one or more masking colorants in the
initial colored state. Suitable migratory activators useful in the
present invention include, for example, neutral polyoxygenated
compounds such as, polyethylene glycols, polypropylene glycols,
polyglycol monoethers or diethers, as well as esters such as, for
example, polypropylene glycol 400, polyethylene glycol 400,
polyethylene glycol 1000, polyethylene glycol 200, polyethylene
glycol 600, polyethylene glycol dimethylether, or polyethylene
glycol monolauate, or nonionic surfactants such as, Triton X 100,
or polyethylene oxide-polypropylene oxide block polymers, such as
Pluronic.RTM.. Other useful compounds such as, amines, e.g.
triethanolamine, dioctylamine, tert-octylamine, Tinuvin 292HP,
Tinuvin 123, polyethyenimines, Primene JM-T-amine, etc., may be
employed as one or more migratory activators in the activating
layer.
[0038] As stated above, the predetermined time period begins upon
the activation of the time validation indicator, i.e. when at least
a portion of the receiving layer is placed in contact with at least
a portion of the activating layer. In one aspect, according to the
present teachings, one or more adhesive materials may be
incorporated into at least the receiving layer, activating layer,
or both, during formation, to bond together at least a portion of
the receiving layer to at least a portion of the activating layer
when placed in contact, as well as in some instances, to other
additional layers of the time validation indicator. In another
aspect, according to the present teachings, as illustrated in FIG.
4, the time validation indicator (10) may further comprise an
adhesive layer (8), that comprises one or more adhesive materials,
such that the receiving layer (4) and the activating layer (6) are
bonded together when at least a portion of the receiving layer (4)
is placed in contact with at least a portion of the activating
layer (6). In further instances, additional adhesive layers may be
utilized to aid in bonding other layers of the time validation
indicator with that of the activating layer or receiving layer. The
adhesive layer may be either a preformed film of the one or more
adhesive materials or in the alternative, prepared by coating the
one or more adhesive materials onto a release base, another layer
of the time validation indicator, e.g. receiving layer or
activating layer, or a base substrate. It should be noted that in
instances where the adhesive layer is formed by coating a layer
onto a release base, the release base is removed prior to
activation of the time validation indicator. The one or more
adhesive materials can be any suitable adhesive known in the art,
e.g. pressure sensitive adhesives such as, natural or synthetic
elastomers, acrylic adhesives, polymers of vinyl ethers or silicone
gums, or those or similar to those described in "Pressure-Sensitive
Adhesives," by T. M. Goulding, Handbook of Adhesive Technology 2nd
Edition, chapter 44 (2003).
[0039] In a further aspect of the present teachings, as illustrated
in FIG. 5, the time validation indicator (14) may further comprise
a colorant layer (12) disposed onto at least a portion of the
receiving layer (4). In other aspects, the colorant layer may be
disposed onto at least a portion of the activating layer. In either
aspect, the colorant layer comprises one or more static colorants
that are capable of being visually observed upon at least a portion
of the one or more masking colorants of the receiving layer being
partially or fully in the final colorless state. Alternatively, one
or more static colorants may be incorporated into the activating
layer, the receiving layer, or both. In any of these instances, the
one or more static colorants, e.g. dyes, pigments, inks, etc.,
provide for an increase in the visual contrast between the initial
colored state and final colorless state of at least a portion of
the one or more masking colorants of the receiving layer, so that a
more apparent or distinct visual color change of the receiving
layer may result. Thus, the one or more static colorants are
generally chosen to display a visual color that substantially
contrasts the initial colored state of the one or more masking
colorants of the receiving layer. In some instances, it may be
desired to incorporate one or more static colorants into the
activating layer or receiving layer or both, as well as render
another one or more static colorants as a colorant layer disposed
onto either the receiving layer or activating layer. In this
aspect, a wider color gamut may be produced by the time validation
indicator to provide a visual contrasting color to that which is
produced by the one or more masking colorants being in the initial
colored state, thereby resulting in a greater distinct indication
of the visual color change of the receiving layer.
[0040] The colorant layer can be prepared by variety methods well
known in the art. For example, coating a layer that is generally
planar on a release base, another layer of the time validation
indicator, e.g. the activating layer or receiving layer, or a base
substrate, the layer being prepared from a formulation. Such
coatings can be deposited by painting, printing, spraying, slot
coating, dip coating, roller coating, bar coating, etc. It should
be noted that in instances where the colorant layer is formed by
coating a layer onto a release base, the release base is removed
prior to activation of the time validation indicator.
Alternatively, an effective colorant layer may be prepared by
extrusion, injection molding, compression molding, calendaring,
thermoforming, etc. In some instances, the colorant layer may also
comprise one or more adhesive materials to aid in bonding the
colorant layer to other layers of the time validation indicator,
e.g. receiving layer or activating layer.
[0041] Referring now to FIG. 6, in a further aspect of the present
teachings, the time validation indicator (18) may optionally
comprise a timing layer (16), disposed onto at least a portion of
either the receiving layer (4) or the activating layer (6), that
further regulates or retards the rate of migration of the one or
more migratory activators into the receiving layer (4), to lengthen
the predetermined time period, if warranted. Suitable materials for
the timing layer may include, but are not limited to, polyacrylics,
polyurethanes, polycarbonates, polyesters, or fluorinated polymers,
and are generally chosen based on the materials ability to slow
migration of the one or more migratory activators from the
activating layer to the receiving layer. In some instances, the
timing layer may also comprise one or more adhesive materials to
aid in bonding the timing layer to other layers of the time
validation indicator, e.g. receiving layer or activating layer. In
other instances, the timing layer may also comprise one or more
static colorants that are capable of being visually observed upon
at least a portion of the one or more masking colorants of the
receiving being partially or fully in the final colorless state.
The timing layer can be prepared by coating a layer, by way of e.g.
painting, printing, spraying, slot coating, dip coating, roller
coating, bar coating, etc., that is generally planar on a release
base, another layer of the time validation indicator, e.g. the
activating layer or receiving layer, or a base substrate, the layer
being prepared from a formulation. It should be noted that in
instances where the timing layer is formed by coating a layer onto
a release base, the release base is removed prior to activation of
the time validation indicator.
[0042] In another aspect of the present teachings, the time
validation indicator may further comprise one or more base
substrates. In some constructions, at least a portion of the
activating layer is disposed onto the one or more base substrates,
whereas in other constructions at least a portion of the receiving
layer is disposed onto the one or more base substrates. Furthermore
in another construction, at least a portion of the activating layer
may be disposed onto one of the one or more base substrates and at
least a portion of the receiving layer may be disposed onto another
one of the one or more base substrates. In some instances, one of
the one or more base substrates may include an indicia area indicia
area that is capable of being visually observed upon at least a
portion of the one or more masking colorants of the receiving layer
being partially or fully in the final colorless state. For example,
as shown in FIG. 7, the time validation indicator (22) includes one
of the one or more base substrates (20) having an indicia area in
the form of the word EXPIRED. FIG. 7A illustrates the time
validation indicator (22) prior to at least a portion of the one or
more masking colorants being partially or fully in the final
colorless state, in which the indicia area is visually
undetectable, whereas FIG. 7B illustrates the visual appearance of
the indicia area of the time validation indicator (22) upon at
least a portion the one or more masking colorants being partially
or fully in the final colorless state. Suitable base substrates to
be used in the present invention may include any material suited
for printing or coating, e.g. Mylar film. In some instances, the
surface of an object may serve as the base substrate. In alterative
instances, an indicia area may be applied onto any of the layers of
the time validation indicator. The indicia area may be printed or
coated onto a base substrate or a layer in the form of a message or
other numeric or alphabetic symbols, or shapes, etc., so that the
indicia area may become visually apparent following the visual
color change of the receiving layer. In a further aspect, the
indicia area may be rendered into the activating layer or receiving
layer by way of incorporating one or more static colorants in the
form of a message or other numeric or alphabetic symbols, or
shapes, etc., so that the indicia area may become visually apparent
following the visual color change of the receiving layer. The
indicia area may be any color or more specifically, a color that
enhances the contrast between the initial colored state and final
colorless state of the one or more masking colorants of the
receiving layer.
[0043] In other aspects, the indicia area may in the form of a bar
code which becomes altered following the migration of the one or
more migratory activators into the receiving layer during the
predetermined time period. In such instance, upon the alteration of
the bar code, a conventional bar code reading device can be used to
read the altered bar code and indicate that the predetermined time
period has elapsed.
[0044] According to the present teachings, the layers of the time
validation indicator include one or more polymers that act as a
binder. Examples of polymers that are useful in each layer of the
present invention include, but are not limited to, acrylic polymers
such as, Elvacite.RTM. (Lucite) 2014 or NeoCryl.RTM. B818 (DSM),
polyurethanes such as, MACE 107-295, or fluorinated polymers, such
as FC 2230. It should be noted that the type of polymer(s) used for
each layer of the time validation indicator may in some instances
be the same, whereas in others, different. The choice of polymer(s)
for each layer will depend on solubility factors associated with
the various materials in each layer. Any type of polymer(s) which
allow the constituents of the activating layer to migrate into the
receiving layer is acceptable for use. Furthermore, in terms of the
receiving layer, the one or more polymers chosen to be included
within such layer also aid the one or more deactivators in causing
and maintaining the one or more masking colorants in the initial
colored state. This is because in some instances, the one or more
deactivators alone may not effectively cause and maintain the one
or more masking colorants in the initial colored state.
[0045] To further aid in the regulation of the predetermined time
period, any of the foregoing layers of the time validation
indicator may further comprise one or more plasticizers.
Plasticizers, most commonly phthalate esters, are additives used in
polymers to impart improved flexibility and durability.
Plasticizers work by embedding themselves between the chains of
polymer(s) thereby increasing the "free volume", and thus
substantially lowering the glass transition temperature (Tg) of the
polymer(s) and making it softer. In other words, as a plasticizer
migrates into the polymer(s) it disrupts the intermolecular forces
between polymer chains and thus allows for better movement between
polymer segments lowering the Tg which allows for easy migration of
other constituents, for example the one or more migratory
activators into that of the receiving layer.
[0046] Additional components that may be incorporated within any of
the foregoing layers of the time validation indicator include, but
are not limited to, dispersant(s), thickener(s), wetting agent(s),
defoamer(s), etc., that do not cause the one or more masking
colorants of the receiving layer to advance to a final colorless
state before the predetermined time period begins. Dispersants,
wetting agents, or defoamers may each be oligomeric, polymeric, or
copolymeric materials or blends containing surface-active
(surfactant) characteristic blocks, such as, for example,
polyethers, polyols, or polyacids. Examples of dispersants include
acrylic acid-acrylamide polymers, or salts of amine functional
compound and acid, hydroxyfunctional carboxylic acid esters with
pigment affinity groups, and combinations thereof, for example
DISPERBYK.RTM.-180, DISPERBYK.RTM.-181, DISPERBYK.RTM.-108, all
from BYK-Chemie, and TEGO.RTM. Dispers 710 from Degussa GmbH.
Wetting agents are suitable surfactant materials, and may be
selected from among polyether siloxane copolymers, for example,
TEGO.RTM. Wet 270, non-ionic organic surfactants, for example,
TEGO.RTM. Wet 500, and combinations thereof. Defoamers may be
organic modified polysiloxanes, for example, TEGO.RTM. Airex
900.
[0047] The timing period between placing the layers of the time
validation indicator in contact with one another and the visual
color change of the receiving layer depends on a series of
variables that are controllable and allow for the manipulation of
the time validation indicator, in accordance with the present
teachings, for various predetermined time periods. Since the visual
color change of the receiving layer depends on the migration
kinetics of the one or more migratory activators, any parameter
that affects such kinetics will, as a result, also affect the
timing period and therefore, may be utilized in varying the timing
period of the present invention to match the predetermined time
period desired. Examples of such parameters include, but are not
limited to, the concentration of the one or more deactivators, the
concentration of the one or more migratory activators, and/or the
types of the one or more migratory activators, all described in
more detail below. It should be noted that the graphs of FIGS. 8-12
were based on a mathematical model derived from the optical density
changes over time, i.e. the relation between density and time of
contact (activation), of various examples of the time validation
indicator of the present teachings. The optical density changes
were measured using a MacBeth Spectrolino. This relationship
provided a mathematical regression which was then used for
normalization and extrapolation to create the graphs illustrated in
FIGS. 8-12.
[0048] By way of example, FIG. 8 depicts the affect varying
concentrations of the one or more deactivators in the receiving
layer have on the timing period of the present invention. In this
example, three different receiving layers were provided that
included malonic acid as the deactivator. The first receiving layer
comprised a malonic acid concentration of 0.25%, the second
receiving layer comprised a malonic acid concentration of 0.50%,
and the third receiving layer comprised layer a malonic acid
concentration 1.00%. In addition, each of the three different
receiving layers also included 0.5% Black Dye 400 as the masking
colorant and 20% FC-2230 fluoroelastomer. Three common activating
layers were provided each comprising 20% polyethylene glycol
dimethylether (PEGDME) as the migratory activator with 20%
plasticizer, P-670, in 28% Elvacite.RTM. 2014. Each receiving layer
was placed in contact with a respective activating layer and then
monitored for changes in optical density over time using a MacBeth
Spectrolino. As shown in FIG. 8, it was determined that by
increasing the concentration of the one or more deactivators, from
0.25% to 1.00%, it took approximately 240 hours longer for the time
validation indicator of the present teachings to reach the same
optical density with 1.00% concentration of the deactivator versus
0.25% concentration of the deactivator. Furthermore, the type of
one or more deactivators, e.g. maleic acid, malic acid, fumaric
acid, terephthalic acid, propyl gallate, etc., can also further
affect the migration kinetics of the one or more migratory
activators into that of the receiving layer of the time validation
indicator of the present teachings.
[0049] In another example, now referring to FIG. 9, the
concentration of the one or more migratory activators may also
influence the timing period of the present invention. In this
example, three different activating layers were provided that
included PEDGME as the migratory activator. The first activating
layer comprised a PEDGME concentration of 2%, the second activating
layer comprised a PEDGME concentration of 10%, and the third
activating layer comprised a PEDGME concentration of 20%. In
addition, each of the three different activating layers also
included 10% P-670 in 28% Elvacite.RTM. 2014. Three common
receiving layers were also provided each comprising 0.5% Black Dye
400 as the masking colorant and 1% malonic acid as the deactivator
in 20% FC-2230 fluoroelastomer. Each activating layer was placed in
contact with its respective receiving layer and then monitored for
changes in optical density over time using a MacBeth Spectrolino.
As seen in FIG. 9, increases in PEGDME concentration, i.e. from 2%
to 10% to 20%, led to a decreased timing period, as expected, since
higher concentration levels of the one or more migratory activators
will increase the rate the one or more masking colorants advance
from the initial colored state to the final colorless state. In
addition to varying the concentration of the one or more migratory
activators, the types of the one or more migratory activators
utilized in the activating layer also affects the timing period of
the present invention, as illustrated in FIG. 10. Now referring to
FIG. 10, six common receiving layers were provided each one having
the same composition as the receiving layers in FIG. 9 and six
different activating layers were provided each having a different
type of migratory activator at 2% concentration with 10% P-670 in
28% Elvacite.RTM. 2014. Each activating layer was placed in contact
with its respective receiving layer and then monitored for changes
in optical density over time using a MacBeth Spectrolino. As
depicted in FIG. 10 the type of migratory activator(s) used within
the activating layer may substantially alter the timing period of
the time validation indicator of the present teachings.
[0050] In addition to the above mentioned parameters, the glass
transition temperature (Tg) and/or the polarity of the polymer(s)
of the activating layer and/or the receiving layer, and/or the
thickness of the layers included in the time validation indicator
can also affect the timing period. In instances where the time
validation indicator also includes an adhesive layer disposed
between the receiving layer and activating layer, the composition
of the adhesive layer may also affect the migration kinetics of the
one or more migratory activators, thereby affecting the timing
period. In other instances where the time validation indicator also
comprises a timing layer disposed between the receiving layer and
the activation layer, the polymer(s), as well as the thickness of
such timing layer, may also affect the migration kinetics of the
one or more migratory activators. Furthermore, it has also been
found that the concentration of the one or more masking colorants
may also influence the migration kinetics of the one or more
migratory activators. For example, in the instance where black
leuco dye(s) are the one or more masking colorants, it was found
that not only the thickness of the receiving layer, but the
concentration of the black leuco dye(s) can affect the amount of
time it takes for such dye(s) to go from an initial colored state
to that of a final colorless state. Therefore, the higher the
concentration of the one or more masking colorants present in the
receiving layer, the longer the timing period, which is also
similar to the affect the concentration of the one or more
deactivators may have on the timing period.
[0051] In any aspect of the time validation indicator of the
present teachings, the final migration kinetics of the one or more
migratory activators can be managed by the use of one or more
plasticizers incorporated into at least the activating layer as
shown by way of example in FIG. 11. In this example three different
activating layers were provided each having 2% PEGDME in 28%
Elvacite.RTM. 2014, as well as plasticizer, P-670. The plasticizer
concentration of the first activating layer was 5%, the plasticizer
concentration of the second activating layer was 10%, and the
plasticizer concentration in the third activating layer was 20%.
Three common receiving layers were also provided, each comprising
0.5% Black Dye 400 with 1% malonic acid in 20% FC-2230
fluoroelastomer. Each activating layer was placed in contact with
its respective receiving layer and then monitored for changes in
optical density over time using a MacBeth Spectrolino. As shown in
FIG. 11, a change in timing period results due to the concentration
level of the P-670 present in the activating layer, i.e. the higher
concentrations of P-670 can lead to faster migration kinetics and
shorter timing periods of the present invention, since the one or
more plasticizers not only lowers the Tg of the FC-2230 polymer
within the receiving layer, but also allows for ease of migration
of the migratory activator PEGDME. In addition to the activating
layer, in some instances, the receiving layer may also comprise one
or more plasticizers, as illustrated by way of example in FIG. 12.
Now referring to FIG. 12, two different receiving layers were
provided, each comprising 0.5% Black Dye 400 with 1% malonic acid
in 20% FC-2230 fluoroelastomer. One of the receiving layers also
comprised a plasticizer, P-670, at 5% concentration. In addition,
two common activating layers were also provided, each having 2%
PEGDME with 10% plasticizer, P-670, in 28% Elvacite.RTM. 2014. Each
receiving layer was placed in contact with its respective
activating layer and then monitored for changes in optical density
over time using a MacBeth Spectrolino. As seen in FIG. 12, in the
instances where both the activating layer and receiving layer
comprise one or more plasticizers, the timing period of the present
invention can be substantially shortened due to the one or more
plasticizers of the receiving layer aiding in the migration
kinetics of the one or more migratory activators. Thus, various
combinations of plasticizer concentrations in the activating layer
and/or the receiving layer can be used to further adapt the timing
period, such that the time validation indicator of the present
teachings can be used to determine the expiration of a wide variety
of time intervals. Optionally, one or more plasticizers may also be
incorporated into any additional layers that may be included within
the time validation indicator of the present teachings to further
aid in the migration kinetics of the one or more migratory
activators.
[0052] The time validation indicator, according to the present
teachings, may be fabricated by any method well known to those
skilled in the art. One such method may include forming a receiving
layer, forming an activating layer, and placing at least a portion
of the receiving layer in contact with at least a portion of the
activating layer to initiate the predetermined time period and the
migration of the one or more migratory activators into the
receiving layer. A variety of methods can be used to form an
effective receiving layer and activating layer. Such methods may
include coating a layer, by way of e.g. painting, printing,
spraying, slot coating, dip coating, roller coating, bar coating,
etc., that is generally planar on a release base, a surface of an
object, another layer of the time validation indicator, or a base
substrate, the layer being prepared from a formulation. It should
be noted that in instances where the receiving layer or activating
layer is formed by coating a layer onto a release base, the release
base is removed prior to activation of the time validation
indicator. Alternatively, an effective receiving layer or
activating layer may be prepared by extrusion, injection molding,
compression molding, calendaring, thermoforming, etc. The placing
of at least a portion of the receiving layer in contact with at
least a portion of the activating layer may include either direct
contact, i.e. no additional layers are disposed between the
activating layer and receiving layer, or indirect contact, i.e. one
or more additional layers are disposed between the activating layer
and the receiving layer, e.g. an adhesive layer and/or a timing
layer. In some instances, the placing of at least a portion of the
receiving layer in contact with at least a portion of the
activating may be done without the use of an adhesive means, while
in other instances adhesive means may be utilized. The adhesive
means, if used, bonds together at least a portion of the receiving
layer to at least a portion of the activating layer when placed in
contact. The adhesive means may be applied by rendering an adhesive
layer onto at least a portion of the receiving layer and/or the
activating layer, or in the alternative by incorporating one or
more adhesive materials into the receiving layer and/or the
activating layer during formation. In another aspect, the method
may further include rendering a colorant layer disposed onto at
least a portion of either the receiving layer or the activating
layer. In other instances, the method may also include applying a
timing layer disposed onto at least a portion of the receiving
layer or the activating layer. In further aspects, the method may
optionally include rendering one or more base substrates, in which
at least a portion of at least the activating layer or the
receiving layer is disposed onto the one or more base substrates.
It should be noted that additional adhesive means may also be
utilized to bond other layers, e.g. colorant layer and/or timing
layer, if present, to that of the activating layer, receiving
layer, or a base substrate.
[0053] The time validation indicators, according to the present
teachings, are applicable to various instances that warrant an
indication of the elapse of a predetermined time period. For
example, the expiration of a shelf-life of an object, general
inventory management, etc. One method for indicating a
predetermined time period has elapsed may include providing a time
validation indicator, in accordance with the present teachings,
placing at least a portion of the receiving layer in contact with
at least a portion of the activating layer to initiate the
predetermined time period and the migration of the one or more
migratory activators into the receiving layer, and detecting the
visual color change of the receiving layer that indicates the
predetermined time period has elapsed. In a further aspect, the
method may also include applying the time validation indicator to
at least a portion of an object. The adaptability of the layers of
the time validation indicator according to the present teachings,
enables the time validation indicator to be utilized for a host of
different time intervals and therefore instances in which visual
indication of the elapse of a predetermined time period is
sought.
EXEMPLIFICATIONS
[0054] The present teachings, having been generally described, will
be more readily understood by reference to the following examples,
which are included merely for the purposes of illustration of
certain aspects and embodiments of the present teachings, and are
not intended to limit the scope of these teachings. It should be
noted that, unless otherwise specified, the weight % values
mentioned in the below examples are measured relative to a solid
state.
Example 1. Preparation of a Time Validation Indicator with a
Predetermined Time Period of Approximately 144 Hours
[0055] Receiving Layer: [0056] To 25.0 g of a magnetically stirred
solution of 20% FC-2230 fluoroelastomer (3M, Dyneon) in ethyl
acetate is added 0.5% (0.025 g) Black Dye 400 from Yamada Chemical
Co., 1% (0.050 g) Malonic Acid from Aldrich Chemical and 5%
Plasthall P-670 from Hallstar (1.39 g based on total weight of
components including the Plasthall). This formulation was stirred
at room temperature for 30 minutes until fully dissolved and then
sonicated (Branson 2200) for 15 minutes at room temperature to
remove air bubbles and to insure a uniform mixture. This
formulation was then coated on a base substrate, Mylar film of 10
mils, using a 20 mil Bird bar and dried at 40.degree. C. for 4
hours and then at 80.degree. C. for 14 hours to yield a receiving
layer.
[0057] Activating Layer: [0058] To 25.0 g of a magnetically stirred
solution of 28% Elvacite.RTM. 2014 (Lucite International/Chempoint)
in toluene is added 20% (0.35 g) polyethylene glycol dimethylether
(Aldrich), and 20% Plasthall-P670 (6.63 g based on total weight of
components including the Plasthall). This formulation was stirred
at room temperature for 30 minutes until fully dissolved and then
sonicated (Branson 2200) for 15 minutes at room temperature to
remove air bubbles and to insure a uniform mixture. This
formulation was then coated on a base substrate, Mylar film of 10
mils, using a 20 mil Bird bar and dried at 40.degree. C. for 4
hours and then at 80.degree. C. for 14 hours to yield an activating
layer.
[0059] Adhesive Layer: [0060] Prepared by coating #9026 transfer
adhesive (3M) onto the activating layer to yield an adhesive layer.
The receiving layer was then cold laminated to the adhesive layer,
thereby placing at least a portion of the receiving layer in
contact with at least a portion of the activating layer to begin
the predetermined time period and initiate the migration of the one
or more migratory activators into the receiving layer causing at
least a portion of the one or more masking colorants to advance to
a final colorless state.
Example 2. Preparation of a Time Validation Indicator with a
Predetermined Time Period of Approximately 4300 Hours
[0061] Receiving Layer: [0062] Prepared as in Example 1.
[0063] Timing Layer: [0064] To 25.0 g of a magnetically stirred
solution of 28% Elvacite.RTM. 2014 is added 5% Plasthall-P670 (1.39
g based on total weight of components including the Plasthall).
This formulation was stirred at room temperature for 30 minutes
until fully dissolved and then sonicated (Branson 2200) for 15
minutes at room temperature to remove air bubbles and to insure a
uniform mixture. This formulation was then coated on a release base
using a 20 mil Bird bar and dried in an oven at 40.degree. C. for 4
hours and then at 80.degree. C. for 14 hours to yield a timing
layer. The timing layer was then heat laminated to the receiving
layer.
[0065] Activation Layer: [0066] To 25.0 g of a magnetically stirred
solution of 28% Elvacite.RTM. 2014 in toluene is added 20% (0.35 g)
polyethylene glycol dimethylether, and 10% Plasthall-P670 (2.95 g
based on total weight of components including the Plasthall). This
formulation was stirred at room temperature for 30 minutes until
fully dissolved and then sonicated (Branson 2200) for 15 minutes at
room temperature to remove air bubbles and to insure a uniform
mixture. This formulation was then coated on a base substrate,
Mylar film of 10 mils, using a 20 mil Bird bar and dried at
40.degree. C. for 4 hours and then at 80.degree. C. for 14 hours to
yield an activating layer.
[0067] Adhesive Layer: [0068] Prepared by coating #9026 transfer
adhesive (3M) onto the activating layer to yield an adhesive layer.
The timing layer was then cold laminated to the adhesive layer,
thereby placing at least a portion of the receiving layer in
contact with at least a portion of the activating layer to begin
the predetermined time period and initiate the migration of the one
or more migratory activators into the receiving layer causing at
least a portion of the one or more masking colorants to advance to
a final colorless state.
Example 3. Preparation of a Time Validation Indicator with a
Predetermined Time Period of Approximately 330 Hours
[0069] Receiving Layer: [0070] To 25.0 g of a magnetically stirred
solution of 20% FC-2230 fluoroelastomer in ethyl acetate is added
1.0% (0.050 g) Black Dye 400, and 1% (0.050 g) malonic acid. This
formulation was stirred at room temperature for 30 minutes until
fully dissolved and then sonicated (Branson 2200) for 15 minutes at
room temperature to remove air bubbles and to insure a uniform
mixture. This formulation was then coated onto a base substrate,
Mylar film of 2 mils, using a 20 mil Bird bar and dried at
40.degree. C. for 4 hours and then at 80.degree. C. for 14 hours to
yield a receiving layer.
[0071] Timing Layer: [0072] To 25.0 g of a magnetically stirred
solution of 28% Elvacite.RTM. 2014 is added 5% Plasthall-P670 (1.39
g based on total weight of components including the Plasthall).
This formulation was stirred at room temperature for 30 minutes
until fully dissolved and then sonicated (Branson 2200) for 15
minutes at room temperature to remove air bubbles and to insure a
uniform mixture. This formulation was then coated on a release base
using a 20 mil Bird bar and dried in an oven at 40.degree. C. for 4
hours and then at 80.degree. C. for 14 hours to yield a timing
layer.
[0073] Colorant Layer: [0074] To 25.0 g of a magnetically stirred
solution of 28% Elvacite.RTM. 2014 in toluene is added 10% (0.70 g)
of Red BSR-RD213 (Brilliant). This formulation was stirred at room
temperature for 30 minutes until fully dissolved and then sonicated
(Branson 2200) for 15 minutes at room temperature to remove air
bubbles and to insure a uniform mixture. This formulation was then
coated onto a base substrate, Mylar film of 2 mils, using a 20 mil
Bird bar and dried at 40.degree. C. for 4 hours and then at
80.degree. C. for 14 hours to yield a colorant layer.
[0075] Adhesive Layer 1: [0076] Prepared by coating #9026 transfer
adhesive (3M) onto the colorant layer to yield an adhesive
layer.
[0077] Activating Layer: [0078] To 25.0 g of a magnetically stirred
solution of 28% Elvacite.RTM. 2014 in toluene is added 10% (0.175
g) polyethylene glycol dimethylether, and 20% Plasthall-P670 (6.30
g based on total weight of components including the Plasthall).
This formulation was stirred at room temperature for 30 minutes
until fully dissolved and then sonicated (Branson 2200) for 15
minutes at room temperature to remove air bubbles and to insure a
uniform mixture. This formulation was then coated on a release
base, Mylar film of 2 mils, using a 20 mil Bird bar and dried at
40.degree. C. for 4 hours and then at 80.degree. C. for 14 hours to
yield an activating layer.
[0079] Adhesive Layer 2: [0080] Prepared by coating #9026 transfer
adhesive (3M) onto the activating layer to yield an adhesive layer.
The adhesive layer 1 was cold laminated to one side of the
receiving layer and the timing layer was cold laminated to the
opposing side of the receiving layer. The adhesive layer 2 was then
cold laminated to the timing layer, thereby placing at least a
portion of the receiving layer in contact with at least a portion
of the activating layer to begin the predetermined time period and
initiate the migration of the one or more migratory activators into
the receiving layer causing at least a portion of the one or more
masking colorants to advance to a final colorless state.
[0081] For the purposes of describing and defining the present
teachings, it is noted that the term "substantially" is utilized
herein to represent the inherent degree of uncertainty that may be
attributed to any quantitative comparison, value, measurement or
other representation. The tem' "substantially" is also utilized
herein to present the degree by which a quantitative representation
may vary from a stated reference without resulting in a change in
the basic function of the subject matter at issue.
[0082] Although the teachings have been described with respect to
various embodiments, it should be realized that these teachings are
also capable of a wide variety of further and other embodiments
within the spirit and scope of the appended disclosure.
* * * * *