WO2002039196A1

WO2002039196A1 - Timing device

Info

Publication number: WO2002039196A1
Application number: PCT/US2000/030697
Authority: WO
Inventors: Steven T. Adamy; Francis R. Cala
Original assignee: Church & Dwight Co., Inc.
Priority date: 2000-11-08
Filing date: 2000-11-08
Publication date: 2002-05-16
Also published as: AU2001214753A1

Abstract

A timing device for visually determining the passage of a preselected period of time including a tube (2) having opposed ends with at least one of the opposed ends having a reservoir (10a, 10b) for storing a reactant or an indicator, a transport system (12) extending from the reservoir to the other of the opposed ends of the tube (2) for transporting at least one of the reactant or the indicator until they contact each other, a reactant, and an indicator which when in contact with the reactant via the transport means (12) emits an observable change in property wherein the minimum length of the period of time corresponds to the time it takes for the reactant and indicator to contact each other. The tube (2) has a shape which undergoes at least two material changes of direction exceeding 90° and up to 180° from one of the opposed ends to the other.

Description

TIMING DEVICE

Related Application

This application is related to U.S. Patent Application Serial No. 09/311 ,949 filed

on May 14, 1999.

Field of the Invention

The present invention is generally directed to a timing device for visually

determining the passage of a preselected period of time which is applicable to a wide

variety of consumer products, especially for products which have an extended shelf or

use life and for which it is desirable to know when the product must be replaced or

rejuvenated. The timing device can be attached to or incorporated in typical packaging

employed for consumer products.

Background of the Invention

Consumer products including food products, cleaning products, deodorizers and

the like have a shelf life determined by the length of time the components of the product

resist change to environmental influences. For example, food products have a given

shelf life based on their ability to resist chemical or physical changes due to contact with air, heat and other influences in the environment. Many consumer products are date

stamped to provide the user with an indication of the shelf life of the product. The shelf

life may be relatively short such as a few days or may be relatively lengthy such as a

few months. Date stamping of consumer products provides the user with some

indication when the product may no longer be useful for its intended purpose.

Quite often, date stamps are printed inconspicuously on the product package.

It is sometimes difficult to read the date stamp and in some cases even to find the date

stamp because it may be printed anywhere on the package. Date stamping is

particularly problematic for products which have a relatively long shelf life because such

products tend to get stored in an obscure recesses of a storage area, such as a food

cabinet or refrigerator. If the product is not used often, the consumer is often unaware

that the expiration date is shortly forthcoming or has even passed.

There have been attempts to provide a visible indication of when the useful life

of a product has expired. So called "life time indicators" are employed for food products

such as disclosed in U.S. Patent Nos. 2,671 ,028; 3,751 ,382; and 3,942,467. These

indicators typically work through chemical reactions initiated or increased in rate by

exposure to high temperatures. Other lifetime indicators rely on diffusion of a

component through a traditional wick or membrane as disclosed in U.S. Patent Nos.

3,414,415; 3,479,877 and 3,768,976, each of which is incorporated herein by reference. Examples of such products include, for example, the Oral-B toothbrush indicator

which is based on the diffusion of a dye out of the bristles. When the color of a select

group of bristles disappears, the user is aware that the toothbrush may or should be

discarded and replaced. Another example is the Glade Neutralizer which is a

deodorizer product having a timer based on the evaporation of a solvent from a polymer

gel and subsequent shrinkage of the gel.

The timing indicators mentioned above suffer from one or more disadvantages

which makes their universal applicability to a wide range of packaged products

problematical. Such disadvantages include a) the timing mechanism is part of the

product (e.g. a deodorizer) and is therefore limited to employment with that product or

that class of products, b) the timing mechanism is inaccurate or cannot be controlled

to accommodate a wide range of product shelf lives, c) the timing mechanism is

expensive and/or d) has a limited range of measurement.

To overcome these problems, Applicants developed a shelf life indicator or

timing device which comprised an inverted U-shaped tube having opposed ends with

at least one of the opposed ends having a reservoir for storing a reactant or an indicator

and a transport means extending from the reservoir to the other of the opposed ends

of the tube for transporting at least one of the reactant or the indicator until they contact

each other. When the reactant and indicator are in contact with each other there is an

observable change of property, such as a color change which may be used as a measure of the passage of certain period of time. Such timing devices are disclosed

in copending U.S. Patent Application Serial No. 09/311 ,949 filed May 14, 1999,

incorporated herein by reference.

It has been observed that when such timing devices are reduced in scale to

accommodate relatively small packages, the measurable period of time is reduced. In

some cases the reduction in the measurable period of time may be reduced to a greater

extent than the reduction in scale of the timing device.

It would therefore be an advance in the art of providing visible indicators for

determining when a product should be replaced or rejuvenated if a cost efficient and

effective shelf life indicator could be provided which provides a clear and distinct visible

indication of when a product should be replaced or rejuvenated. It would be a further

advance in the art if a shelf life indicator could be provided which enables the consumer

to see how much time is remaining for the shelf life of the product which indication is

accurate and clearly visible. It would be a still further advance in the art if a shelf life

indicator could be provided which maintained a useful measurable period of time even

when reduced in scale to accommodate relatively small packages. Summary of the Invention

The present invention is generally directed to a shelf life indicator hereinafter

referred to as a "timing device" for determining the remaining shelf life of a product and

visually displaying the same which has applicability to a wide range of consumer

products and packages containing the same. The timing device can be applied to

products which have a relatively short shelf life (e.g. dairy products including milk) and

products which have a fairly long shelf life such as canned vegetables.

In a particular aspect of the present invention, there is provided a timing device

for determining and visually displaying the passage of a preselected period of time

comprising:

a) a tube having opposed ends with one of the opposed ends extending

downwardly below the level of the remaining portion of the tube, one of said opposed

ends having a reservoir for storing a reactant or an indicator, said tube undergoing at

least two material changes in direction from one of the opposed ends to the other;

b) transport means extending from the reservoirto the other of the opposed

ends of the tube for transporting at least one of the reactant or the indicator until they

contact each other;

c) a reactant; and

d) an indicator which when in contact with the reactant via the transport

means emits an observable change in a property wherein the minimal length of the period of time corresponds to the time it takes for the reactant and indicator to contact

each other.

Methods of employing the device, packages employing the device and methods

of manufacturing the device also constitute a part of the invention set forth herein.

Brief Description of the Drawings

The following drawings in which like reference characters indicate like parts are

illustrative of embodiments of the invention and are not intended to limit the invention

as encompassed by the claims forming part of the application.

Figure 1 is a front elevational view of a first embodiment of the timing device of

the present invention;

Figure 2 is a front elevational view of a second embodiment of the timing device

of the present invention;

Figure 3 is a front elevational view of a third embodiment of the timing device of

the present invention; Figure 4 is a front elevational view of a fourth embodiment of the timing device

of the present invention;

Figure 5 is a front elevational view of a fifth embodiment of the timing device of

the present invention;

Figure 6 is a front elevational view of a sixth embodiment of the timing device of

the present invention;

Figure 7 is a front elevational view of a seventh embodiment of the timing device

of the present invention;

Figure 8 is a perspective view of the timing device of Figure 1 contained within

a product package with the entire timing device visible; and

Figure 9 is a perspective view of the timing device of Figure 1 contained within

a product package with spaced apart portions of the timing device visible;

Detailed Description of the Invention

The present invention is generally directed to a timing device for visually

determining the passage of a preselected measurable period of time in which the timing device has particular applicability to visually indicating the remaining shelf life of a

product, especially consumer products such as food products and household products.

The main component of the timing device is a tube which contains two components, a

reactant and an indicator as more fully described hereinafter. The shape of the tube

is particularly adapted to accommodate a desirable measurable period of time on

relatively small packages although such devices may be readily applied to all sized

packages including large packages as well. Contact of the reactant and indicator

directly or indirectly produces a visible change in at least one property, preferably a

color change which can indicate that the product should be replaced or rejuvenated, the

amount of time which has passed since the product was used, and/or the amount of

time remaining before the product must be replaced or rejuvenated. Of particular

importance to the present invention is the pathway provided by the tube enabling the

reactant and indicator to come into contact with each other. Control over the shape of

the tube enables control over the period of time it takes for the reactant and indicator

to come into contact and where in the timing device they come into contact which

provides the timing device with the means by which the above-mentioned measurable

periods of time can be realized.

It has been observed from timing devices employing an inverted U-shaped tube

disclosed in Applicants' copending U.S. Serial No. 09/311 ,949 filed May 14, 1999 that

a reduction of scale to accommodate relatively small packages may result in an even

larger reduction in the period of time which may be measured with the smaller scale timing device. By way of example, a timing device of the type disclosed in said

copending application having a height of about 9 cm and a tube diameter of about 0.6

cm was able to provide a measurable period of time of about 52 days. When the same

timing device using the same structural components, reactant and indicator was

reduced in scale by about 30% there resulted about a 70% reduction in the measurable

period of time. A further reduction in scale of about 30% resulted in about a 40%

further reduction in the measurable period of time.

The present invention was developed to at least reduce the significant decrease

in the measurable period of time as a result of reducing the scale of the timing device

to accommodate relatively small packages. To this end, Applicants determined that by

increasing the number of "material changes of direction" as hereinafter defined of the

flowing indicator or reactant as compared to the inverted U-shaped tube, the speed of

flow may be reduced and the reduction in the length of the measurable period of time

is eliminated or at least minimized. As used herein the term "material change of

direction" shall mean a change of the flow direction of the indicator or reactant in the

tube of greater than 90° and up to 180°. The number of material changes of direction

can be computed by determining the number of times that undergoes a change of

greater than 90° and up to 180° before commencing another change in direction.

A first embodiment of the timing device of the present invention is shown in

Figure 1. The tube generally defines a pathway having at least three material changes of direction (i.e. at least three changes of direction of at least 90° up to 180°) which

enables a slower flow of the reactant or indicator as compared with an inverted U-

shaped tube. The tube 2 is comprised of a pair of spaced apart and parallel leg

portions 4a and 4b connected to each other through a curvilinear central portion 6 providing at least three material changes in direction for the flow of the fluid contained therein as hereinafter explained. The opposed leg portions 4a and 4b and the central

portion 6 thereby define a continuous passageway 8.

Each of the leg portions 4a and 4b have a corresponding reservoir 10a and 10b

at the respective ends of the leg portions 4a and 4b. At least one of the reservoirs will contain a reactant and the other of the reservoirs may contain an indicator as explained

in more detail hereinafter. As shown in Figure 1 , one of the leg portions (e.g. leg

portion 4a) extends further downward than the other leg portion (e.g. leg portion 4b).

In one embodiment of the invention, the reactant is contained within one of the reservoirs and the indicator is contained within the other of the reservoirs 10a and 10b.

In accordance with the present invention, there is provided a means for transporting at least one of the reactant and the indicator so that they may contact each other and

thereby cause a visible change in property (e.g. a color change) which is an indication

of the passage of time corresponding to all or a portion of the shelf life of a product. The preferred transportation means represented by 12 in Figure 1 is a porous

material, most preferably a wicking material which can absorb the reactant and/or the

indicator and allow the reactant and/or indicator to pass therethrough.

The preferred wicking materials are those selected from the group consisting of

woven fabrics, non-woven fabrics and combinations thereof. What is particularly

important for the wicking material is to enable the reactant and/or indicator to move

therethrough and travel at least a portion of the distance from one reservoir to another.

The distance of travel must be sufficient to enable the reactant and indicator to contact

each other and thereby react producing a visible change in a property such as a color

change.

The time it takes for a liquid to pass through a wicking material is dependent on

how well the liquid wets the material. The employment of polar liquids and wicking

materials of lower polarity generally result in longer wicking times. Polar liquids and

polar wicking materials generally result in a timing device where the passage of the

liquid is more rapid (i.e. shorter wicking times).

Specifically preferred wicking materials include polyesters, polyacrylates,

polyacrylamides, polypropylene, polyethylene terephthalate and copolymers thereof,

cellulosic materials (including but not limited to natural or synthetic cotton, wood, paper

and cellulosic polymers), wool, fiberglass, silica gel, ceramics and combinations thereof. Low polarity wicking materials include polypropylene and polyethylene

terephthalate. Relatively high polarity wicking materials include paper, cotton, wool and

silica gel. The polarity of the wicking material can be altered and hence the time of

travel of the liquid therethrough by producing blends of low and high polarity wicking

materials. An example of such a blend is the combination of polyethylene terephthalate

and cotton which are typically made by cross linking the hydroxyl groups of the cotton

with reactive functional groups of the polyethylene terephthalate.

The density of the wicking material may be a factor in controlling the rate of

absorption of the reactant and/or indicator. Generally, the denser the wicking material,

the slower the rate of adsorption. By selecting a suitable wicking material and density

thereof, one is able to control the rate at which the reactant and/or indicator proceeds

through the wicking material to enable the reactant and indicator to come into contact

with each other and thereby cause a visible change in properties.

The physical structure of the wicking material also can influence the rate at which

a fluid passes through the timing device. For example, fluid flow can be affected by the

type of weave and whether the wicking material has a uniform profile (e.g. having a

uniform circular cross-section) or has a non-uniform profile such as a corrugated

structure or combinations thereof. The tube 2 as shown in Figure 1 can be fabricated from any number of materials

including plastics and glass. It is preferred that the material used to construct the tube

2 be unbreakable to prevent injury to the consumer. Preferred materials are plastics

including, for example, polyethylene and polyethylene terephthalate.

The tube 2 must enable the user to observe a color change or other change of

property that occurs within the tube. Thus, the term "clear" as used herein means that

the tube can be transparent or translucent, but not opaque. The tube 2 itself may be

colored so long as the color change taking place within the tube can be observed by

the user.

The reactant and indicator may be selected from solids, liquids or gases so long

as the reactant and indicator are able to contact each other. Liquid reactants and

indicators are preferred because gaseous reactants and indicators tend to travel over

a relatively short period of time because they more readily diffuse through the tube 2

and are more difficult to control using the wicking material present therein. Where

desirable, one, but not both of the indicator and reactant may be a solid.

The reactant and indicator are selected so that when in contact with each other

there is a visible change of properties such as a color change. The reactant can be

selected from acids, bases, oxidizing agents and reducing agents. The indicators are

those materials which when in contact with the reactant cause the change in properties which are visible to the user. For example, indicators include litmus compounds, methyl

orange, bromocresol green and congo red.

The change in property which results in a change observable by the user may

be from the direct interaction of the indicator and reactant or through an intermediary

substance. Direct interaction indicators are those which change color through direct

contact with the reactant. Examples of direct indicators are so-called redox indicators

such as thymolindolphenol and neutral red. Thymolindolphenol is colorless in its

reduced form. Upon contact with a suitable oxidizing agent (e.g. Fe⁺³),

thymolindolphenol is oxidized and thereby turns blue.

Neutral red is likewise colorless in reduced form. When oxidized in the presence

of a suitable oxidizing agent, neutral red turns red. Other redox reactions may be

employed to effect a visible color change including the conversion of CrO₂ ^" (green) to

CrO/² (yellow).

The above-mentioned redox systems are examples of direct interaction systems.

Such systems produce a change of property by direct reaction of the reactant and

indicator.

In some reactant-indicator systems, it is possible to extend the time before the

reactant and indicator react to produce a change of property by employing a scavenger for one of them. For example, a reactant (Fe⁺³), scavenger (Cu⁺¹) and indicator (e.g.

thymolindolphenol) are contained within the timing device. Before the indicator can

undergo a color change, the reactant first reacts with the scavenger. Alternatively,

another method of obtaining a further delay is to initiate a series of reactions such that

a first reactant and a co-reactant produce a first intermediate. The first intermediate

can either react with the indicator or with a second co-reactant to produce second

intermediate which second intermediate reacts with the indicator to produce a color

change. Any number of intermediary reactions and intermediates may be employed as

desired.

Other reactant-indicator pairs and scavengers used therewith are known and

available such as the employment of a system including Ti⁺² (indicator), Fe⁺³

(scavenger) and neutral red (indicator).

In another reactant-indicator system, the reactant may be water which induces

a color change from a reactant which is an anhydrous compound. For example, cobalt

chloride is an anhydrous compound which is blue. Upon contact with water (reactant),

the cobalt chloride converts to the hydrated form which has a pink color. Other

anhydrous compounds which are suitable for use in the present invention would be

known to those of ordinary skill in the art. In the embodiment shown specifically in Figure 1 , there is employed two

reservoirs 10a and 10b. The reactant may be contained in the reservoir 10a and the

indicator may be contained in the reservoir 10b. The wicking material 12 is contained

within the passageway 8 extending from the reservoir 10a to the reservoir 10b. The

selection of a suitable wicking material will enable at least one of the reactant and

indicator to travel up the wicking material until the reactant contacts the indicator. If

both the reactant and indicator travel through the wicking material, they will meet at

some location in the wicking material depending on the relative rates of absorption of

the reactant and indicator. Thus, the visible color change will take place at some point

along the wicking material and the time it takes for that visible color change to take

place is the period of time coinciding with the desirable shelf life of the product. If

desired, a portion of the tube may be opaque or hidden so that a visible window area

is present at a different location than where the reactant and indicator initially react. If

the indicator is not absorbed by the wicking material then the color change will take

place in the reservoir 10b after the reactant has traveled the full distance through the

wicking material from the reservoir 10a and to the reservoir 10b.

For longer periods of time, the reactant (which can be a solvent) may be a liquid

or in solution and the indicator may be solid. The tube is opaque except for a window.

The liquid traverses the tube to reach the solid indicator, dissolves the indicator, and

draws the dissolved indicator back along the wicking material until the window portion

of the tube is reached and a visual observation can be made. The employment of a reactant and indicator pair provides a fixed period of time

before a color change takes place depending on the type and density of the wicking

material. Quite often, it is desirable to modify the rate at which the reactant and/or the

indicator travel through the wicking material in order to provide a longer or shorter shelf

life measurement which may be accomplished by adding a viscosity modifying agent.

The employment of a viscosity modifying agent is dependent in part on the recognition

that when the reactants and/or indicators are liquids they typically move through the

wicking material in opposite directions which will impede the forward progress of each

flow. Furthermore, the viscosity of the reactant and/or indicator will have an effect on

the rate of movement of the same through the wicking material. As previously indicated

if a modification of the rate of movement is desired a viscosity modifying agent may be

used.

In accordance with the present invention, a viscosity modifying agent may be

added either to the reactant or to the indicator or to both. The viscosity modifying

agent, depending on its viscosity, can be used to speed up or slow down the rate of

travel of the reactant and/or indicator. The slowing down of the travel time is desirable

when the shelf life of the product is relatively long. The speeding up of the travel time

is desirable for those products having a relatively short shelf life.

Viscosity modifying agents for use in the present invention are desirably

compatible with the other components (i.e. reactants and indicators) in that they do not cause any change in the composition of the components or the manner in which they

react with each other. Another desirable property of the viscosity modifying agents is

that they are able to be absorbed and passed through the wicking material without

adversely affecting the reactant and indicator. Still further, it is desirable that the

viscosity modifying agent be nontoxic, particularly when associated with products used

by consumers. Typical examples of viscosity modifying agents for use in the present

invention include water, glycerine, alkylene glycols (e.g. propylene glycol) and

combinations thereof.

The amount of the reactant, indicator, and optional viscosity modifying agent will

vary. The amounts selected for each of the components are made to ensure a visible

change in property after a desirable preselected period of time (i.e. the length of the

time of the shelf life of the product). The amount of each of these components should

be sufficient to travel through the wicking material for the estimated distance of travel

to have contact of the reactant and indicator. This represents a minimum amount of the

components to achieve the desired time period measurement. More than the minimum

amount of each component can be used to ensure a proper reaction at a desirable

location within the timing device. Generally, the amount of the reactant is at least

0.01% by weight and most typically from about 0.01 to 5.0% by weight, based on the

total weight of the materials of the reactant solution. The amount of the indicator is

typically at least 0.01 % by weight, most typically within the range of from about 0.01 to

0.5% by weight and the amount of the viscosity modifying agent, if necessary, may approach 100% by weight of the indicator and/or reactant solution and is typically in the

range of from about 25 to 75% by weight based on the weight of the respective solution.

In an important aspect of the present invention, the flow rate of the indicator or

reactant throughout the tube is controlled by providing at least two material changes of

direction as previously defined for the timing device when affixed to a substrate such

as a product package. In a preferred form of the invention there will be at least two

material changes of direction equal to or about 180°.

As specifically shown in Figure 1 , the flow of the indicator or reactant from the

reservoir 10a undergoes a first material change of direction from point (x) to point (y)

and a second material change of direction from point (y) to point (z). The change of

direction from point (x) to point (y) is about 180° as is the change in direction from point

(y) to point (z). In the embodiment of Figure 1 , the timing device provides for leg

portions 4a and 4b to extend upwardly to the same elevation. In other embodiments

of the invention, the respective leg portions extend upwardly to different elevations (e.g.

leg portion 4a may extend upwardly to an elevation exceeding the elevation of leg

portion 4b).

Referring to Figures 2 and 3, the respective timing devices 2 have one leg

portion which extends above the other leg portion. In particular, Figure 2 shows a

timing device in which the leg portion 4a extends above the leg portion 4b while in the embodiment of Figure 3, the leg portion 4b extends above the leg portion 4a. In each

embodiment the tube is shaped so that the indicator or reactant must travel through

three material changes of direction before reaching the opposed end of the tube.

The embodiments of Figures 2 and 3 will generally provide a shorter measurable

period of time than the embodiment of Figure 1 because the total length of the

respective tubes is shorter than the length of the tube in the embodiment of Figure 1

(please confirm that this is correct). Thus, the length of the tube may be a factor in

customizing a timing device with a desirable measurable period of time for a particular

application.

As previously indicated, the timing device of the present invention employs at

least two material changes of direction in the pathway for the flow of an indicator or

reactant. In the embodiments of Figures 1-3, each material change of direction is about

180°. In the embodiment shown in Figure 4, one of the material changes of direction

is less than 180°. Referring to Figure 4, the timing device 2 provides a tube 20 with

respective leg portions 24a and 24b, curvilinear central section 26, and respective

reservoirs 30a and 30b defining a pathway 28 for the flow of the indicator and/or

reactant. The tube 20 has a first material change of direction from point (x) to point (q)

of less than 180°. In this embodiment, the change from point (x) to point (q) is about

135° and results in generally a shorter measurable period of time then the measurable

period of time resulting from about a 180° change in direction as used exclusively in the embodiments of Figures 1-3. Thus, the angle of each material change of direction may

be a factor in customizing a timing device with a desirable measurable period of time

for a particular application.

In the embodiments of Figures 1-4, the tube is curvilinear as evidenced by

reference numeral 6 at the position where the pathway defined by the tube undergoes

a material change of direction. As shown in the embodiment of Figure 5, the leg

portions need not be curvilinear and may assume a more angled shape. In particular,

Figure 5 shows a timing device 30 having a leg portion 34a which changes direction in

a series of 90° angles so that each segment 36 of the tube is perpendicular to an

adjacent tube segment. For example, tube segment 36a is perpendicular to tube

segment 36b which is perpendicular to tube segment 36c, etc. The embodiment of

Figure 5 provides a pathway that undergoes three material changes of direction of

about 180°C from point (x) to point (y) and from point (y) to point (z) as with the

embodiment of Figures 1-3, but generally provides a longer measurable period of time

than the previous embodiments. Thus, the employment of straight or curvilinear

pathways may be a factor in customizing a timing device with a desirable measurable

period of time for a particular application.

More than two material changes of directions may be used to increase the

measurable period of time. By way of example, an embodiment showing four material

changes of direction in the form of coils is shown in Figure 6 between consecutive points (s), (t), (u), (v) and (w). It will be appreciated that the number of material of

material changes of direction can be increased by increasing the number of coils within

the timing device.

In a further embodiment of the invention as shown in Figure 7, a circular pathway

comprised of a plurality concentric loops 47 for the timing device may be employed with

each looped circuit amounting to two material changes of direction (two 180° changes

of direction).

In each of the embodiments of the invention, previously described, the reactant

contained within a reservoir (e.g. 10a) travels the entire length of the wick until it

reaches the reservoir (e.g. 10b) containing the indicator at which time a color change

occurs. The time it takes for the reactant to travel through the wick and into the

reservoir 10b containing the indicator corresponds to the desired shelf life of the product

and when the color change occurs the user knows that the product should be discarded

or rejuvenated. In special "window" embodiments, the period of time and the initial

reaction time are not the same; rather the desired period of time is for a color change

to occur at a particular location along the tube.

In another embodiment of the invention both the reactant contained in the

reservoir 10a and the indicator contained in the reservoir 10b travel through the wicking

material and eventually contact each other at some point within the passageway 8 of the device 2. By suitably selecting reactants and indicators as well as the type and

density of the wicking material, and optionally a viscosity modifying agent, the point of

contact of the reagent and indicator and their time of travel can be accurately predicted

and controlled.

The embodiments of the present invention as described provide for the

movement of the reactant alone or the movement of both the reactant and the indicator

through the wicking material and eventual contact causing a visible color change. It will

be understood that in accordance with the present invention, the reactant may remain

within the reservoir 10a while the indicator moves from the reservoir 10b through the

wicking material over the entire length of the passageway 8 into the reservoir 10a

where a reaction occurs causing a color change. In all of these embodiments the

occurrence of a color change coincides with the useful shelf life of the product. When

the color change occurs, the product is discarded or rejuvenated.

However, the present invention is applicable to the employment of a color

change as a continuous indication of the passage of time so that the user can readily

identify how much time has passed since the product has been used and how much

time remains until the product must be discarded. In this embodiment of the invention,

it is desirable to place either the reactant or the indicator throughout the wicking

material and let the other of the reactant and indicator be absorbed through the wicking material from one of the reservoirs causing a continuous color change from one

reservoir to the other.

For example, if a product has a useful shelf life of approximately five weeks, the

timing device of the present invention may be marked with weeks 1 -5 (i.e. wk1 =the first

week; wk2=the second week, etc). Thus, as the color change commences from the

beginning of use of the product and passes to the marker indicating week one (wk1 ) the

user will know that one week has passed since the product was used and about four

weeks remain before the product must be discarded. It will be understood that the

timing device can be constructed so that longer or shorter periods of time may be

indicated depending on the type of reactant and indicator, the type and density of the

wicking material, and the optional use of a viscosity modifying agent.

The timing device of the present invention can be contained within a package or

housing which has one or more ports or windows that enables the user to view the

device to observe a color change at one or more locations.

Referring to Figures 8 and 9 , there is shown an embodiment of the timing device

shown in Figure 1 contained within a housing 50 of a package 52 which contains a

consumer product. The housing 50 provides sufficient space to house the timing device

2. The housing 50 has a front face 54 with a clear window 56 enabling the viewer to

view the entire timing device as specifically shown in Figure 8. In this embodiment of the invention, the user can view the entire timing device as discussed above in

connection with Figures 1-7. Thus, all color changes and the location of all color

changes can be observed by the user.

In another embodiment of the invention as shown in Figure 9, the package 52

may be provided with a housing 50 in which the front face 54 contains one or more

ports or windows 58 which shows periodic color changes through the window indicating

the passage of a fixed period of time such as one week or one month. If only one

window is used, it should be at the point that there is a final color change indicating that

the product needs to be replaced or rejuvenated. The employment of multiple windows

58 enables the user to periodically observe how much time has passed and how much

time remains of the product shelf life. In the specific embodiment of Figure 9, there are

seven windows with the first two windows indicating a color change. If each window

was indicative of the passage of one week of time, then the product would have been

used for two weeks with about four weeks remaining of the product shelf life.

The timing device of the present invention can be affixed to a product by

adhesive or the like or can be prepackaged with the product as indicated in the

embodiments of Figures 8 and 9. In some cases, it is desirable to package the reactant

and indicators in the respective reservoirs within a breakable container which can be

broken by pressure applied to the user. Such containers include capsules made of a

variety of materials including gelatins and the like. The breakable capsules enable the user to commence the start of the product life and thereby disregard the period of time from manufacture to purchase by the user.

The wicking material employed in the timing device of the present invention may

be arranged in a uniform profile or a non-uniform profile. The term "uniform profile"

shall mean that the cross-sectional area and shape of the wicking material is the same throughout the length thereof. The term "non-uniform profile" shall mean that the cross-

sectional area and shape of the wicking material is not the same throughout the length thereof.

As previously indicated the timing device may employ a reactant or indicator which is comprised of a solid material. The reservoir 10b may contain a solid indicator

(e.g. cobalt chloride) while a reservoir 10a contains a liquid reactant (e.g. water). Water travels from the reservoir 10a to the reservoir 10b to cause a color change (e.g. from

blue to pink) which is observable through the window 26.

The time for a color change to occur will in part be dependent on the time it takes

the reactant (e.g. water) to reach the solid indicator (e.g. cobalt chloride). It will be observed that contact of the liquid reactant and solid indicator will result in the formation of a solution in the reservoir 10b. Due to capillary action, and concentration gradients,

the solution (which will have a pink color in the example mentioned above) will migrate toward the reservoir 10a. As a consequence, it is possible to place a window along the path of the wicking material to observe the "pink" colored solution. Thus the length of

the period of time can be extended because the liquid indicator must first travel from

reservoir 10b to 10a to cause a color change therein and then for an additional period

of time until the colored solution in the reservoir 10a reaches the window where it is

observed by the consumer. Alternatively, the solid indicator may be placed in reservoir

10b and liquid reactant may be placed in reservoir 10a.

Example 1

A timing device of the type shown in Figure 1 was constructed by inserting into

the tube grade 3 chromatographic paper obtained from Whatman, Inc. of Clifton, New

Jersey as the wicking material. Reservoirs were made from the bulbs of 0.5 ml

disposable pipettes obtained from Samco Scientific Incorporated of San Fernando,

California.

A reactant solution was prepared by combining 7.35 weight % of deionized

water, 66.18 weight % of glycerin, 24.51 weight % of propylene glycol and 1.96 weight

% of glacial acetic acid. An indicator solution was prepared by combining 7.50 weight

% of deionized water, 67.47 weight % of glycerin, 24.98 weight % of propylene glycol

and 0.05 weight % of litmus. The reactant solution was clear while the indicator

solution was blue. In order to activate the timing mechanism, 0.6 ml of the indicator solution was

placed in the indicator reservoir and 0.6 ml of the acidic solution was placed in the

reactant reservoir. The wick was then placed in the reservoirs until each end of the

wick touched the bottom of the reservoirs. The entire assembly was then wrapped in

a covering of plastic film.

The timer duration was noted as the time it took the indicator reservoir to turn

from blue to red. Multiple samples were tested in this matter at 40°F in a refrigerator

or in a thermostatic chamber which maintained a constant temperature of 80°F and a

relative humidity of 80%. The results are shown in Table 1.

Table 1

Samples Duration (Room Temp.)

Figure 2 28±4 days

Figure 3 34±4 days

Both embodiments of Figures 2 and 3 provided significantly longer measurable

periods of time than that obtained using an inverted U-shaped tube of the same height

and tube diameter.

Claims

What Is Claimed Is:

1. A timing device for determining the passage of a preselected period of

time comprising:

(a) a tube having opposed ends with one of the opposed ends

extending downwardly below the level of the remaining portion of the tube, one of said

opposed ends having a reservoir for storing a reactant or an indicator, said tube

undergoing at least two material changes in direction from one of the opposed ends to

the other;

(b) transport means extending from the reservoir to the other of the

opposed ends of the tube for transporting at least one of the reactant or the indicator

until they contact each other;

(c) a reactant; and

(d) an indicator which when in contact with the reactant via the

transport means emits an observable change in a property wherein the minimum length

of the period of time corresponds to the time it takes for the reactant and indicator to

contact each other.

2. The timing device of claim 1 wherein each of said opposed ends has a

reservoir.

3. The timing device of claim 2 wherein the reactant is initially present in a

first reservoir at one of said ends and the indicator is present in a second reservoir at

the other of said ends.

4. The timing device of claim 1 wherein at least one of said reactant and said

indicator is a liquid.

5. The timing device of claim 4 wherein each of said reactant and indicator

is a liquid.

6. The timing device of claim 5 wherein the reactant is selected from the

group consisting of an acid and a base.

7. The timing device of claim 6 wherein the indicator changes color when

contact by the reactant.

8. The timing device of claim 1 wherein the indicator comprises a color

changing compound and a viscosity modifying agent and the reactant optionally further

comprises a viscosity modifying agent.

9. The timing device of claim 8 wherein the viscosity modifying agent is

selected from the group consisting of water, glycerine, alkylene glycols and mixtures

thereof.

10. The timing device of claim 1 wherein the transport means is comprised

of porous material.

11. The timing device of claim 1 wherein the transport means is comprised

of a wicking material.

12. The timing device of claim 1 wherein the wicking material is selected from

the group consisting of woven fabrics, non-woven fabrics and combinations thereof.

13. The timing device of claim 1 wherein the wicking material is selected from

the group consisting of polyesters, polyacrylates, polyacrylamides, polypropylene and

copolymers thereof, natural or synthetic cellulosic materials, wood, paper, cellulosic

polymers, cotton, wool, fiberglass, silica gel, ceramics and combinations thereof.

14. The timing of device of claim 3 wherein at least one of the reactant and

indicator are present in the wicking material.

15. The timing device of claim 1 further comprising location means for

identifying a location on the transport means where a desirable observable change

occurs corresponding to said preselected period of time.

16. The timing device of claim 1 wherein the indicator is an anhydrous

compound and the reactant is water.

17. The timing device of claim 1 further comprising a scavenger material.

18. The timing device of claim 17 wherein the reactant reacts with the

scavenger material preferentially to prevent substantial reaction of the reactant with the

indicator until the scavenger material is substantially consumed.

19. Thetiming device of claim 1 further comprising an intermediary substance

wherein the reactant reacts with the intermediary substance to produce a second

reactant which reacts with the indicator to produce said observable change of property.

20. The timing device of claim 1 wherein the reactant or indicator is a solid

material.

21. The timing device of claim 1 wherein the other of said reactant or indicator

travels via the transport means to the solid material.

22. The timing device of claim 21 wherein the reactant and indicator contact

each other to produce said liquid exhibiting a change of property, said period of time

including the length of time it takes the liquid to travel a predetermined distance through

the wicking material.

23. The timing device of claim 1 comprising a first pair of leg portions defining

a first material change of direction and a second pair of leg portions defining a second

material change in direction.

24. The timing device of claim 23 wherein the highest point of the first pair of

leg portions is the same as the highest point of the second pair of leg portions.

25. The timing device of claim 23 wherein the highest point of the first pair of

leg portions is different than the highest point of the second pair of leg portions.

26. The timing device of claim 25 wherein the highest point of the first pair of

leg portions is greater than the highest point of the second pair of leg portions.

27. The timing device of claim 25 wherein the highest point of the first pair of

leg portions is less than the highest point of the second pair of leg portions.

28. The timing device of claim 23 wherein the leg portions of the first pair of

leg portions are perpendicular to each other.

29. The timing of claim 1 wherein the tube comprises at least three material

changes of direction.

30. The timing device of claim 1 wherein at least one material change of

direction is equal to or about 180°.

31. The timing device of claim 30 wherein each material change of direction

is equal to or about 180°.

32. A package having on an outer surface thereof a timing device of claim 1.

33. The package of claim 32 comprising a first pair of leg portions defining a

first material change of direction and a second pair of leg portions defining a second

material change in direction.

34. The package of claim 33 wherein the highest point of the first pair of leg

portions is the same as the highest point of the second pair of leg portions.

35. The package of claim 33 wherein the highest point of the first pair of leg

portions is different than the highest point of the second pair of leg portions.

36. The package fo claim 35 wherein the highest point of the first pair of leg

portions is greater than the highest point of the second pair of leg portions.

37. The package of claim 35 wherein the highest point of the first pair of leg

portions is less than the highest point of the second pair of leg portions.

38. The package of claim 33 wherein each leg portion of the first pair of leg

portion is perpendicular to the other leg portion.

39. The package of claim 32 wherein said tube comprises at least three

material changes of direction.

40. The package of claim 32 wherein at least one material change of direction

is equal to or about 180°.

41. The package of claim 40 wherein each material change of direction is

equal to or about 180°.

42. A method of determining the passage of a preselected period of time

corresponding to the useful life of a product comprising:

attaching to said product or to a package containing said product a timing

device of claim 1.

43. The method of claim 42 comprising controlling the rate of flow of at least

one of the reactant and indicator through the transport means.

44. The method of claim 42 comprising selecting a point on said transport

means as a measure of the distance of travel of at least one of the reactant and

indicator corresponding to the preselected period of time.

45. The method of claim 42 wherein the reactant and indicator are contained

within separate breakable containers, said process further comprising breaking said

containers to commence the preselected period of time.