GB2307298A

GB2307298A - Cutlery item with temperature indication

Info

Publication number: GB2307298A
Application number: GB9624150A
Authority: GB
Inventors: William James Stephen Barker
Original assignee: B&H Liquid Crystal Devices Ltd
Current assignee: B&H Liquid Crystal Devices Ltd
Priority date: 1995-11-20
Filing date: 1996-11-20
Publication date: 1997-05-21
Anticipated expiration: 2016-11-20
Also published as: GB9624150D0; GB2307298B; GB9523672D0

Abstract

An item of cutlery, for example a baby's spoon, has a gathering portion and a handle, at least the gathering portion being designed to undergo a reversible visual change in appearance e.g. a colour or transparency change, when its temperature passes from one side to the other side of a predetermined temperature (or temperature range). The predetermined temperature (or temperature range) is selected so that the gathering portion will exhibit a specific visual appearance, indicating that foodstuff is at an unsafe temperature to eat, when the gathering portion is inserted into, and heated or cooled by, the foodstuff.

Description

An Item of Cutlery This invention relates to an item of cutlery and in particular, but not exclusively, to a baby's spoon. The invention also relates to a method of testing whether foodstuff is too hot or too cold to consume safely.

It is known for articles to undergo a reversible change of colour or other change of appearance when subjected to a change of temperature. Typical of such articles are liquid thermometers which display information at different temperatures. Another known article of this kind is a temperature-responsive food probe disclosed in GB A-2244132 which is intended to be inserted into heated food to indicate whether the food has been heated to a suitable temperature. Children's feeding spoons are also known which undergo a reversible change of colour when inserted into warm or cool food. However these known feeding spoons are intended to change colour when inserted into any food heated a little above or cooled a little below normal temperatures so as to provide a novelty device for the user.In other words the feeding spoon is deliberately designed to change colour or appearance at normal food temperatures. It is not intended as a safety device to indicate whether the food into which the spoon is inserted is too hot or cold to be safely eaten.

Another known article comprises a plastics baby's spoon incorporating a traditional glass thermometer within the handle and spoon bowl. When the spoon bowl is inserted into foodstuff, the temperature of the foodstuff can be viewed through the handle. Thus it can be readily seen whether the foodstuff is too hot or too cold for a baby to eat. However this known spoon is relatively expensive and has safety and hygiene drawbacks.

The present invention seeks to provide an item of cutlery which undergoes a reversible temperature responsive change of appearance if inserted into foodstuff which is at such a temperature that it cannot be safely devoured.

According to one aspect of the present invention an item of cutlery having a gathering portion and a handle is characterised in that at least the gathering portion is designed to undergo a visual change in appearance when its temperature passes from one side to the other side of a predetermined temperature or temperature range and to reverse the visual change in appearance when its temperature passes back from the other side to said one side of said predetermined temperature or temperature range, the predetermined temperature or temperature range being selected so that foodstuff at any temperature to said other side of said predetermined temperature or temperature range is at such a temperature that it cannot be safely or reasonably consumed by a user of the item of cutlery.

The predetermined temperature or temperature range is selected in dependence on the intended use of the item of cutlery. If, for example, the item of cutlery is intended as a child's or infant's spoon for indicating whether foodstuff is too hot to eat, the predetermined temperature or temperature range is conveniently selected to be the minimum safe temperature, e.g. a specific temperature within the range of from 370C to 480C, preferably from 410C to 450C, at which a heated foodstuff can be safely eaten by the child or infant. In normal use the gathering portion of the spoon will be below this predetermined temperature or temperature range and will have a particular visual appearance.If, however, the gathering portion is inserted into foodstuff having an excessive temperature, the gathering portion will be heated above the predetermined temperature or temperature range (i.e. to the said other side thereof) and will undergo a reversible visual change in appearance indicating that the foodstuff is too hot to be safely eaten by the child or infant. Alternatively, a child's or infant's spoon could be designed to indicate if foodstuff is too cold to be safely eaten. In this case the predetermined temperature or temperature range would be chosen to be the maximum safe temperature, e.g. OOC, at which foodstuff can be safely eaten by the child or infant.

Any foodstuff below this temperature (i.e. to the said other side thereof) would be indicated as being unsuitable to consume on insertion of the gathering portion of the spoon into foodstuff.

Another application of the invention may be as a spoon for use with hot drinks or soups, to indicate to the user if the foodstuff is too hot to be drunk or consumed.

In this case, where the intended user will most probably not be a child or infant, the predetermined temperature or temperature range would be considerably higher, e.g. at a specific temperature within the range of from about 900C to 980C.

An item of cutlery may be designed so that the gathering portion has two different predetermined temperatures or temperature ranges, e.g. one to indicate if a foodstuff is too hot to be safely consumed and one to indicate if a foodstuff is too cold to be safely consumed.

In all applications, however, the item of cutlery is specifically designed with safety in mind - i.e. it is only intended to undergo a visual change in appearance if, on insertion of the gathering portion into the foodstuff to be consumed, the gathering portion indicates that the temperature of the foodstuff is too hot, or in other applications too cold, to be safely consumed by the user.

Preferably the reversible visual change in appearance comprises a reversible colour change. In this specification the word "colour" includes a colourless condition unless the context requires otherwise. In this case the item of cutlery is preferably. but not necessarily, a one-part moulding of plastics material comprising a thermochromic composition mixed with a non-thermochromic plastics resin.

The thermochromic composition is selected so as to reversibly change colour when passing through said predetermined temperature or temperature range, i.e. the thermochromic composition reverts to its original colour when its temperature passes back through the predetermined temperature or temperature range. Preferably the change occurs at a specific temperature or over a narrow temperature range, e.g. of up to about 2-30C. Conveniently, if heated from below to above the predetermined temperature (range), the thermochromic composition changes its chemical structure, losing its original colour and becoming clear.

This leaves the item of cutlery with the "base" colour of the non-thermochromic plastics resin (which could be clear or tinted). The non-thermochromic plastics resin can be of any suitable type, although a polypropylene plastics resin has been found to be a good all round material which is robust, easily mouldable, safe, unbreakable, non-toxic and dish-washer proof. The thermochromic composition suitably comprises a number of thermally reactive compounds, which are microencapsulated in a known manner and incorporated in a plastics resin, suitably of the same type as that of the non-thermochromic plastics resin for mixing with the latter.

The clearing point of the thermochromic composition system can be adjusted in a predictable manner by varying the substances mixed within it. Thus a system which clears around a specific temperature with one formulation clears at a different temperature when a different formulation is mixed.

According to another aspect of the present invention there is provided a method of testing the temperature of foodstuff to determine whether it is at a safe temperature to eat, comprising inserting the gathering portion of an item of cutlery according to said one aspect of the invention into foodstuff and observing whether the gathering portion changes visually to indicate that the foodstuff is at an unsafe temperature to consume.

A specific embodiment of the invention will now be described in the following non-limitative example.

EXAMPLE A mouldable plastics resin was created by admixing a first polypropylene plastics resin incorporating a microencapsulated thermochromic composition with a differently coloured secondary polypropylene plastics resin in a ratio typically of from 1:33 to 1:10 of first to secondary polypropylene resin. The thermochromic liquid composition was selected to have a "clearing point" of around 430C. The resulting resin composition was moulded in a single moulding operation to form a one-piece baby's or infant's feeding spoon of plastics material which was safe, not easily broken, non-toxic and dishwasher proof.

In use, the thermochromic composition changes its chemical structure and loses its colour, becoming clear, at the clearing point. Thus if the spoon is inserted into a heated foodstuff, liquid or solid, at a temperature above the clearing point, the thermochromic composition loses it original colour and becomes clear as it is heated above the clearing point temperature indicating that the foodstuff is too hot to be safely consumed. This leaves the spoon, when hot, with the "base" colour of the secondary plastics resin, which may be clear or tinted, for example a pink colour.

When the spoon is at a "cold" temperature (i.e. below the clearing point temperature), the colour, e.g. blue, of the primary plastics resin is visible. Since the thermochromic liquid crystal composition undergoes reversible colour change, the spoon can be used repeatedly. The spoon is designed to provide a visual indication to the user if the foodstuff into which the spoon is inserted is too hot (or possibly too cold) to consume.

Claims

1. An item of cutlery having a gathering portion and a handle, characterised in that at least the gathering portion is designed to undergo a visual change in appearance when its temperature passes from one side to the other side of a predetermined temperature or temperature range and to reverse the visual change in appearance when its temperature passes back from the other side to said one side of said predetermined temperature or temperature range, the predetermined temperature or temperature range being selected so that foodstuff at any temperature to said other side of said predetermined temperature or temperature range is at such a temperature that it cannot be safely or reasonably consumed by a user of the item of cutlery.

2. An item of cutlery according to claim 1, wherein the predetermined temperature or temperature range lies within the range of from 370C to 480C and temperatures at said other side of this temperature range are in excess thereof.

3. An item of cutlery according to claim 2, wherein the predetermined temperature or temperature range lies within the range of from 410C to 450C. and temperatures at said other side of this temperature range are in excess thereof.

4. An item of cutlery according to claim 1, wherein the predetermined temperature or temperature range lies within the range of from about 900C to 980C and temperatures at said other side of this temperature range are in excess thereof.

5. An item of cutlery according to any of the preceding claims, in which the gathering portion has two different non-overlapping predetermined temperatures or temperature ranges, the gathering portion having different visual appearances when at a temperature between said two predetermined temperatures or temperature ranges than when at a temperature below one, or above the other, of said predetermined temperatures or temperature ranges.

6. An item of cutlery according to any of the preceding claims, wherein the said reversible change in appearance comprises a reversible colour change.

7. An item of cutlery according to any one of the preceding claims, wherein said gathering portion is moulded from plastics material comprising a thermochromic composition mixed with a non-thermochromic plastics resin.

8. An item of cutle.ry according to claim 7, wherein said thermochromic composition is selected so as to reversibly change colour when passing through said predetermined temperature or temperature range.

9. An item of cutlery according to claim 8, wherein the thermochromic composition,if heated from below to above the predetermined temperature (range), changes its chemical structure, losing its original colour and becoming clear.

10. A method of testing the temperature of foodstuff to determine whether it is at a safe temperature to eat, comprising inserting the gathering portion of an item of cutlery as claimed in any one of the preceding claims into foodstuff and observing whether the gathering portion changes visually to indicate that the foodstuff is at an unsafe temperature to consume.

11. An item of cutlery substantially as herein described with reference to the Example herein.