GB2316385A

GB2316385A - Insulated container with thermochromic indicator

Info

Publication number: GB2316385A
Application number: GB9715817A
Authority: GB
Inventors: Alan Nigel Bainbridge; Bruce Alfred Barham; Nicholas Hugh Sanders
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1996-08-15
Filing date: 1997-07-25
Publication date: 1998-02-25
Anticipated expiration: 2017-07-25
Also published as: EP0837011A1; GB2316385B; GB9715817D0

Abstract

A container suitable for containing a food or beverage comprises an insulating sleeve to which a thermochromic ink has been applied that indicates when the contents of the container have reached an acceptable temperature for consumption. Preferably the ink undergoes a reversible colour change over a range of temperatures, which may be either hot or cold. Preferably the insulating sleeve comprises an expanded polystyrene material, which is approximately 160 microns thick. Another preferable feature is a dispensing system comprising a thermostatically controlled cabinet in combination with one or more of such containers.

Description

7 (C) 2316385 A TEMPERATURE SENSITIVE CONTAINER

Field of the Invention The present invention relates to a container suitable for containing a food or beverage that has an insulating 10 sleeve to which a thermochromic ink has been applied that indicates when the contents of the container has reached an acceptable temperature for consumption. is Background and prior art Food and beverage products are commonly stored in containers such as metal cans to prevent or at least significantly restrict microbial spoilage prior to 20 consumption. These generally contain baked beans, chicken soup, peaches or the like which are heat treated, canned, and stored for some months before being removed form the canned, cooked and consumed. Metal cans are also used to store soft drinks. They are best chilled 25 before consuming. Like soft drinks, some food and beverages are purchased by people,on the go" at railway stations, garage forecourts, airports or offices corridors. The decision 30 is often one of impulse to satisfy an immediate need or desire. These projucts are often ambient stable for convenient storing and vending. However some products need to be stored or served at a particular temperature to be acceptable or indeed safe for consumption. 35 Thermochromic inks or paints can be used to visually signal the approximate temperature of an object. They

F 3147(C) 2 have been applied to or incorporated within wrist watches (U.S. 5,430,692), fish lures (U.S. 5,222,320) and toys (U.S. 4,917,643). And the colour change that occurs can be permanent or reversible.

These inks have also been used in the food industry.

For example, U.S. patent specification 5,114,112 discloses a food service system wherein individual portions of pre-cooked food are supported on trays within moveable carts. Each cart contains a number of food trays that support a food dish which can be covered by an insulated dome that has a thermosensitive knob. The colour of the member indicates whether the food on the dish is still at a safe heating temperature.

U.S. patent specification 4,805,188 discloses a time temperature indicator for closed vessels, such as pressure cookers and sterilizers, which has ready visibility around a 3600 angle and can function as a lifting knob.

The present inventors have been faced with the problem of conveniently and cost effectively providing a container for a food or beverage which needs to be cooled or heated to a certain temperature for consumption with means which indicates to a potential consumer that the contents of the container is ready to be consumed. This can be achieved by applying a thermochromic ink to the container which reversibly indicates when the contents of the container has reached and still retains an acceptable temperature for consumption. However at that temperature the container may be too uncomfortable to handle comfortably. Therefore the exterior surface of the can should be insulated and the thermochromic ink applied to at least a portion thereof.

F 3147 (C) 3 Statement of Invention

The present invention relates to a container suitable for containing a food or beverage that has an insulating sleeve to which a thermochromic ink has been applied that indicates when the contents of the container has reached an acceptable temperature for consumption.

Preferably the ink undergoes a reversible colour change over a range of acceptable temperatures.

Preferably the insulating sleeve comprises an expanded polystyrene material.

is The present invention also relates to a dispensing system for ready to consume food or beverage products comprising a temperature variable cabinet in combination with a number of food or beverage containers that have an insulating sleeve to which a thermochromic ink has been 20 applied that indicates when the contents of the container has reached an acceptable temperature for consumption. Detailed description of the invention 25 The container of the present invention is'one that is suitable for containing a food or beverage, particularly one that needs to be cooled or heated to a certain temperature for consumption. Aluminium cans such as 30 those used to contain soft drinks are readily available at relatively low cost but one skilled in the art will appreciate that any number of container shapes, sizes or materials (eg steel or a mixture of steel and aluminium to name but a few) could be used. For present purposes 35 the container will merely be described as a can.

F 3147 (C) 4 The can could contain a wide variety of food and beverage products. Foods such as soups and sauces and beverages such as tea, coffee and chocolate are particularly suitable. The word "teal' is intended to include black, green, oolong, rooibos and mate tea. Naturally herbal and other plant and vegetable matter infusions could also be used. Both coffee and chocolate are available in various forms. Like tea, any coffee or chocolate beverage compositions could include sugar or some other sweetener, milk or some other whitener, cream or some other creamer, flavour, nutritional supplement etc.

in a first preferred embodiment of the present invention the container is an aluminium can that contains a tea, coffee or chocolate drink that is intended to be heated to and consumed at about 550C. It can be uncomfortable for some people to handle a can having its contents at such a temperature and therefore the exterior of the can is provided with an insulating sleeve.

The choice of material for the insulating sleeve can be very important. A number of insulating materials are commercially available but they are often too thick, unsightly or expensive to be suitable for the purpose.

After much experimentation the present inventors found that expanded polystyrene is surprisingly suitable. The thickness of the material should be between 100 and 500 microns. Any less and the can may be too hot for some people, any more and the insulating effect is such that the thermochromic ink may need to be reformulated to give a true indication of the temperature of the contents of the can. The expanded polystyrene should preferably be between 150 and 300 microns thick, 160 microns being particularly preferred. One skilled in the art could determine suitable thicknesses where the contents of the can should be consumed at a higher or lower temperature.

F 3147(C) A thermochromic ink is applied to the insulating sleeve in order to indicate when the contents of the container is at an acceptable temperature for consumption. Such inks are well known and commercially available7 The ink can be applied to the insulating sleeve by any art known means, for example by a flexographic or gravure printing process. The ink could be applied to the entire outer surface of the sleeve but is more cost effective and convenient to restrict the application to discrete areas. one skilled in the art would appreciate that the number and size of these areas could vary greatly but achieve essentially the same result. One might even incorporate the inked area or areas in a logo. The present inventors however p:refer to apply the ink to small predetermined regions on an insulating material that covers at least the sides of the can.

In the preferred embodiment described above the thermochromic ink is capable of reversibly indicating that the contents of the can is at a temperature of between 450C and 550C and thus suitable for immediate consumption. The colour of the ink changes from blue at 450C (or below) to red at 550C (or higher) In a second preferred embodiment a container of 'the present invention is intended to contain a food or beverage that is should be consumed when cold. More specially the contents of the container should be between 10C and 5'C prior to consumption. The container is provided with an insulating sleeve to which a thermochromic ink is applied that is capable of reversibly indicating when the contents of the container is between those temperatures.

F 3147 (C) 6 The containers of the present invention may be stored in a heating or cooling cabinet at the point of sale. The temperature of the cabinet is preferably thermostatically controlled so that the contents of the can wil-1 be held within the temperature range that is required for consumption.

Some of the cans displayed may not be sold on a given day so they may be allowed to return to amb-Lent temperature and reheated or cooled the following day. It is therefore an important (but not necessarily an essential) aspect of the present invention that the thermochromic colour change is reliably reversible or at least otherwise repeatable. The thermochromic ink must be formulated accordingly. The present inventors have found that THERMELION brand inks are suitable for this purpose, especially MSC 41229.

one could if desired apply two differently formulated thermochromic inks to a container such that one can undergo a reversible colour change while the only can only undergo a permanent colour change. In that way there will be a record as to whether a particular container has already been heated or cooled to a certain temperature.

The invention will be now be described with reference to the following examples.

ExamDle 1 Containers of the present invention in the form of metal (aluminium) can were filled with a chocolate milk beverage. The beverage is a hot chocolate which can be stored at ambient temperature but is intended to be consumed at a temperature of about 550C. The entire F 3147 (C) 7 external surface of each can was sealed with expanded polystyrene for insulation. A thermochromic ink was applied to small regions of the sides of the cans. The ink is a THERMELION brand ink (specifically MSC 41229).

The cans were then placed in a heating cabinet. The colour of the ink changed from blue at about 450C to red at about 550C. When the cabinet was turned off the inks became blue again. The cycle was repeated to ensure the colour change was fuIly reversible.

Exam,Dle 7, Cans such as those used in Example 1 were heated to temperatures ranging from 400C to WC and gripped tightly in the palm of the testers hand. The calliper of 160 microns was found to provide the desired insulation at 450C to 550C.

F 3147 (C) 8

Claims

1. A container suitable for containing a fooa or beverage that has an insulating sleeve to which a thermochromic ink has been applied that indicates when the contents of the container has reached an acceptable temperature for consumption.

2. A container according to claim 1 wherein the thermochromic ink reversibly changes colour over a predetermined temperature range.

3. A container according to claim 1 or 2 wherein the insulating sleeve comp:ises an expanded polystyrene material.

4. A container according to any preceding claim wherein the insulating sleeve is between 100 and 500 microns in thickness, especially 150 to 300 microns in thickness.

5. A container according to claim 4 wherein the insulating sleeve is about 160 microns in thickness.

6. A container according to any preceding claim wherein the contents should be above room temperature prior to consumption and the thermochromic ink reversibly indicates when that temperature has been achieved.

7. A container acording to claim 1 wherein the contents should be between 450C and 550C prior to consumption and the thermochromic ink reversibly indicates when the contents of the container is between those temperatures.

F 3147 (C) 9

8. A container according to claim 1 wherein the contents should be below room temperature prior to consumption and the thermochromic ink reversibly indicates when that temperature has been -achieved. 5

9. A container according to claim 1 wherein the contents should be between 50C and 150C prior to consumption and the thermochromic ink reversibly indicates when the contents of the container is between those temperatures.

10. A container according to any preceding claim wherein the contents is soup, sauce, tea, coffee or chocolate.

11. A dispensing system for ready to consume food or beverage products comprising a temperature variable cabinet in combination with one or more containers according to any one of the preceding claims.

12. A dispensing system according to claim 11 wherein the temperature of the cabinet is thermostatically controlled so that the contents of the can will be held within the temperature range that is required for consumption.