GB2395910A

GB2395910A - A bag incorporating a region adapted to change colour upon exposure to a temperature variation

Info

Publication number: GB2395910A
Application number: GB0228118A
Authority: GB
Inventors: Susan Wymer
Original assignee: NAT WHEAT BAG Co Ltd
Priority date: 2002-12-03
Filing date: 2002-12-03
Publication date: 2004-06-09
Also published as: GB0228118D0

Abstract

A bag 2 is filled or adapted to be filled with stuffing material, the bag comprising at least a region 22 adapted to change colour upon exposure to a temperature variation. The bag 2 may be made of textile and the stuffing material may be wheat, barley, rice, corn or foam. The bag 2 may be filled with a smaller bag 16 filled with stuffing material. The bag 2 may be heated in an oven or microwave oven. The regions 22 change colour on sensing a temperature variation from a first (lower) temperature to a second (higher) temperature and the region may comprise a plurality of spots 22 or dots which may be located over a majority of or substantially the whole surface of the bag 2. The region 22 may remain at a second colour when exposed to the second temperature range. The region 22 may comprise thermochromatic ink or dye which changes colour when exposed to the temperature variation.

Description

- The present invention relates to bags and particularly, although not

exclusively, to wheat bags and apparatus for 5 producing same.

Wheat bags are known and are used to treat muscular stress, bruising and everyday aches and pains. The wheat bag is first heated in a microwave oven or conventional 10 oven etc., and then placed onto a distressed area of the body for instant soothing, or relaxation.

In addition, wheat bags can be used to soothe young children when they are ill and also assist them to get to 15 sleep. However, it is not always easy to entice the child in to holding the warm wheat bag when he or she is ill or tired, and so the soothing effects of the wheat bag are not experienced.

20 It is an aim of the present invention to address the above problems associated with wheat bags.

According to a first aspect of the present invention, there is provided a bag filled or adapted to be filled 25 with stuffing material, the bag comprising at least a region thereof adapted to change colour upon exposure to a temperature variation.

Preferably, the bag comprises textile material. The 30 stuffing material may comprise wheat, barley, rice, corn or foam material. The bag may be any suitable shape. The bag may be in the form of an animal or the like, for example, a teddy bear. The bag may be filled, or adapted

to be filled, with at least one smaller bag, said smaller bag being filled or adapted to be filled with stuffing material. 5 The temperature variation may comprise a temperature increase from a first temperature range to a second temperature range. The temperature increase may be effected by heating the bag in an oven, microwave oven, or the like. The temperature variation may comprise a 10 temperature decrease from the second temperature range to first temperature range. The temperature decrease may be effected by allowing the bag to cool.

The region of the bag that changes colour may change 15 colour on sensing a temperature variation of the contents of the bag.

Preferably, the at least one region is a first colour when in the first temperature range. Preferably, the at least 20 one region is a second colour when in the second temperature range.

Preferably, the at least one region changes from the first colour to the second colour when heated from the first 25 temperature range to the second temperature range. The at least one region may change from the second colour to the first colour when cooled from the second temperature range to the first temperature range. The at least one region may change colour temporarily or permanently when exposed 30 to the temperature variation.

The at least one region may be on an internal and/or an external surface of the bag.

In a first embodiment, the at least one region may comprise a plurality of spots or dots preferably located over a majority of, or over substantially the entire outer surface of, the bag. Preferably, the plurality of spots or 5 dots are located over a body section of the animal which may be a teddy bear. The plurality of spots may be located over at least one limb of the animal.

Preferably, in the first embodiment, the first colour is a 10 colour which is substantially the same as the colour of the bag, for example, a dark colour. Preferably, the second colour is a colour which is substantially dissimilar from the colour of the bag. The second colour may be for example, red or orange or yellow. However, the 15 second colour may be colourless.

Preferably, in the first embodiment, the first temperature range is approximately less than 45 C. Preferably, the second temperature range is greater than approximately 20 45 C. Preferably, the at least one region is the first colour when in the first temperature range, and preferably, the at least one region is the second colour when in the second temperature range.

25 Preferably, in the first embodiment, the at least one region changes from the second colour to the first colour when the temperature is cooled from the second temperature range to the first temperature range.

30 In a second embodiment, the at least one region may be arranged to spell a warning, for example, "Too Hot".

Preferably, in the second embodiment, the first colour is a colour substantially the same as the colour of the bag,

for example, a dark colour. Preferably, the second colour is a colour which is substantially dissimilar from the colour of the bag, for example, red or orange. However, the second colour may be colourless.

Preferably, in the second embodiment, the first temperature range is less than approximately 65 C.

Preferably, the second temperature range is greater than approximately 65 C. Preferably, the at least one region is 10 the first colour when in the first temperature range, and preferably, the at least one region is the second colour when in the second temperature range.

Preferably, in the second embodiment, the at least one 15 region changes from the second colour to the first colour when the temperature cools from the second temperature range to the first temperature range.

In a third embodiment, the at least one region may be 20 arranged to spell the warning "Over-heated" or some other suitable warning signal. Preferably, in the third embodiment, the first colour is a colour substantially the same as the colour of the bag, for example, a dark colour.

Preferably, the second colour is a colour which is 25 substantially dissimilar from the colour of the bag, for example, red or orange. However, the second colour may be colourless. Preferably, in the third embodiment, the first temperature 30 range is less than approximately 85 C. Preferably, the second temperature range is greater than approximately 85 C. Preferably, the at least one region is the first colour when in the first temperature range, and

preferably, the at least one region is the second colour when in the second temperature range.

Preferably, in the third embodiment, the at least one 5 region does not change from the second colour to the first colour when the temperature varies from the second temperature range to the first temperature range.

Preferably, in the third embodiment, the at least one region remains the second colour once exposed to the 10 second temperature range.

The bag may comprise any combination of the first, second and third embodiments of the at least one region.

15 Preferably, the bag comprises at least one region as defined in the first embodiment, and a smaller bag comprises at least one region as defined in the second and third embodiments.

20 Preferably, the at least one region comprises thermochromatic ink or dye which changes colour when exposed to the temperature variation. Preferably, the at least one region is printed or treated with ink or dye.

25 The thermochromatic ink may comprise a colour substance and a binder.

The colour substance may comprise thermochrome which is preferably, aqueous. The colour substance may comprise 30 black aqueous thermochrome. Preferably, the binder is colourless.

Preferably, the colour substance and binder are mixed at a ratio of between approximately 1:2 to 1:4, more preferably 1:25 to 1:35, and most preferably 26%:74%.

5 According to a second aspect of the present invention, there is provided a bag filled or adapted to be filled with stuffing material, the bag comprising a safety device adapted to change colour upon exposure to a temperature variation. According to a third aspect of the present invention there is provided a safety device adapted to be attached to an article, the device comprising at least one region which is adapted to change colour upon exposure to a temperature 15 variation.

Preferably, the safety device is adapted to be attached to the bag or article, preferably such that it may only be removed by damaging the bag and/or article and/or the 20 safety device itself. Preferably, the safety device comprises a safety tag, label or button etc. Preferably, the device comprises at least one region which is adapted to change colour upon exposure to a temperature 25 variation. Preferably, the at least one region comprises a temperature sensitive substance.

Preferably, the temperature sensitive substance is printed onto a surface, for example, a sheet, sticker or other 30 suitable surface. Preferably, the device comprises support means adapted to support the surface on which the temperature sensitive substance is printed. Preferably, the support means and preferably, the surface, each

comprise locating means, preferably adapted to engage with each to thereby facilitate easy location of the surface in or on the support means.

5 Preferably, locating means comprises a protrusion on the support means and, preferably, a cut-away section on the surface, said cut-away section having a complimentary shape to that of the protrusion.

10 Preferably, the support means is substantially planar and preferably circular. Preferably, the device comprises a stem section projecting transversely away from the support means, preferably from a centre thereof. Preferably, the device is adapted to be secured to the bag or article, 15 preferably by passing the stem section therethrough.

Preferably, the temperature variation comprises a temperature increase from a first temperature range to a second temperature range, and preferably a temperature 20 decrease from the second temperature range to the first temperature range. Preferably, the first temperature range is approximately less than 75 C. Preferably, the second temperature range is greater than approximately 75 C.

25 Preferably, the at least one region is a first colour when in the first temperature range and, preferably a second colour when in the second temperature range. The first colour may be substantially opaque, preferably, black. The second colour may be substantially transparent, 30 preferably, colourless.

Preferably, the at least one region may be arranged to give a suitable signal, for example, to spell the word

"OK" when in the first temperature range. Preferably, the at least one region may be arranged to give a warning, for example, to spell the word "Too Hot" when in the second temperature range.

Preferably, the at least one region is adapted to change from the first colour to second colour when the temperature increases from the first to second temperature range, and preferably, from the second colour to the first 10 colour when the temperature decreases from the second to the first temperature range.

Preferably, the at least one region which changes colour upon exposure to a temperature variation, comprises a 15 permanent ink which spells the warning signal "Too Hot".

Preferably, the ink is fluorescent preferably red, orange or yellow. Preferably, the warning signal is substantially covered over with a thermochrome ink or dye which changes colour when exposed to the temperature variation.

20 Preferably, the at least one region is printed or treated with ink or dye. The thermochromatic ink may comprise a colour substance and a binder.

The thermochrome ink may be opaque when at the first 25 temperature range, preferably, black. Preferably, a region is left reversed out to spell the suitable signal "OK" thereunder. Preferably, the thermochrome is opaque when at the first temperature range thereby covering over the warning "Too Hot" leaving the signal "OK" visible.

30 Preferably, the thermochrome is substantially transparent preferably colourless when at the second temperature range thereby revealing the warning "Too Hot".

Advantageously, and preferably, the "OK" signal disappears due to that thermochrome being reversed out at this region. Advantageously, and preferably, when the temperature drops from the second temperature range to the 5 first temperature range, the black colour returns thereby covering over the warning "Too Hot" and revealing "OK" once again.

The article may be a wheat bag. The article may comprise 10 food or food packaging, for cooking in an oven or microwave. The food may comprise for example, pizza, or popcorn or chips etc. The article may be a hot water bottle or a container, for example, a drinks container.

Preferably, the article is adapted to experience a 15 temperature variation, preferably an extreme temperature variation. For example, the safety device may be adapted to be used by skiers to identify extreme cold. The article may be a ski. The safety device may be adapted to be attached to an aircraft wing to show and/or monitor 20 freezing temperatures.

All the features described herein may be combined with any of the above aspects, in any combination.

25 For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will be made, by way of example, to the accompanying drawings, in which: 30 Figure 1 shows a schematic front view of a bag; Figure 2 shows a schematic rear view of the bag;

Figure 3 shows a schematic view of a wheat bag in a first configuration; Figure 4 shows a schematic view of a wheat bag in a second 5 configuration; Figure 5 shows a schematic view of the bag as shown in figures 1 and 2 in a second configuration; 10 Figure 6 shows a perspective view of printing apparatus used to manufacture the wheat bag; Figures 7a, 7b and 7b show front, side and rear views respectively, of a safety device; Figures 8a and 8b show front views of the safety device in first and second configurations, respectively; Figure 9 shows a perspective view of the safety device in 20 position on a wheat bag; Figure 10 shows a perspective view of spot printing; and Figure 11 shows a perspective view of flood printing.

Referring to Figure 1, there is shown a bag comprising a textile material generally in the form of a teddy bear 2 having a head 4, body 6, two arms 8 and two legs 10. The head 4 of the bag 2 is filled with a stuffing material, 30 for example, foam etc., and the arms 8 and the legs 10 are either filled with foam material or with wheat grains 17.

Figure 2 shows the reverse side of the bag 2 having an opening 12 to a pouch (not shown) provided along the rear of the body 6.

5 Referring to Figures 3 and 4, there is shown a wheat bag 16 which is generally square in shape and which contains wheat grains 17. The wheat bag 16 is sized such that it may be inserted through the opening 12 shown in Figure 2, and in to the pouch at the rear of the bag 2. Once the 10 wheat bag 12 has been inserted into the pouch, the bag 2 (and wheat bag 16), may then be heated, for example, in a microwave, until it is at an 'ideal' temperature for soothing a user's body. Alternatively, the heated bag 2 can be used to assist a child in getting to sleep. The 15 warmed bag 2 may be either placed on to a distressed area of the body or simply held by a child and its soothing properties experienced.

The 'ideal' soothing temperature has been found to be in 20 the region of about 45+3 C. At 45+3 C, the bag 2 is hot enough to soothe the user for a substantial duration of time, but not so hot that the user may be burned and injured. In order to inform the user that the wheat bag 16 is at this 'ideal' soothing temperature of 45+3 C, the 25 surface of the bag 2 has been printed with a heat sensitive dye (thermochromatic ink) at positions 22 as shown in Figure 5. The apparatus and method of printing the heatsensitive dye onto the surface of the bag 2 is shown in Figures 6, 10 and 11, and will be described 30 hereinafter.

At room temperature, the heat-sensitive dye is a black colour and, therefore, invisible when printed onto a dark

or black fabric 26. However, upon exposure to the ideal temperature of about 45+3 C by micro-waving, the heat sensitive dye is chemically altered thereby changing its colour from black to red dots or spots at positions 22 5 over the bag 2. When red, the dots 22 resemble measles and thereby entice the child to hold the bag 2. As the bag 2 cools over time, the colour of the spots at positions 22 fades until at about room temperature, when they are black and, hence, invisible once again.

However, because the bag 2 and wheat bag 16 are heated in a microwave or normal oven, it is possible that temperatures in excess of the ideal soothing temperature of 45+3 C are reached. Obviously, this can be very 15 undesirable in circumstances where a person, especially a child, may immediately hold the bag 2 in order to experience its soothing properties since burning may occur causing distress. Therefore, a 'warning system' has been incorporated into the wheat bag 16 in order to warn the 20 user, perhaps a child's parent, that it is too hot to use at present and that they should allow it to cool down before use on the child.

The warning system consists of printing the surface of the 25 wheat bag 16 with a heat-sensitive dye at positions 18 and 20 as shown in Figure 4. At room temperature, the heat-

sensitive dye is substantially dark and, therefore, invisible. However, when the wheat bag 16 is exposed to a temperature of about 65+3 C, the heat-sensitive dye 30 changes chemically such that it becomes visible. The heat-

sensitive dye is chemically different to the dye used for the spots 22 which change colour at 45+3 C, in that the

dye at position 18 changes colour at a higher temperature range. The heatsensitive dye at position 18 is arranged to spell 5 the words "Too Hot" as shown in Figure 4. If the bag is heated to this temperature, the user will be informed that it is too hot to use at present, and he or she must wait for the wheat bag 16 to cool down until it is at the ideal soothing temperature of about 45+3 C at which point the 10 "Too Hot" message at position 18 will have returned to a black colour and, therefore, is invisible. At this temperature, the dye at the spots at positions 22 will still be red and so the bag 2 may be used to soothe a user. A further warning system incorporated into the wheat bag 16 is required if it has been over heated such that irreparable damage has occurred to the wheat grains 17.

The surface of the wheat bag 16 has been printed with a 20 heat-sensitive dye at position 20 which is arranged to spell the word "Over Heated". This heat-sensitive dye only becomes visible when exposed to a temperature of about 85+3 C. If the wheat bag is heated to this temperature, the wheat 17 in the wheat bag 16 will have been damaged 25 and it should be discarded and replaced with a new wheat bag 16.

It should be appreciated that the temperatures disclosed herein are given by way of example only, and that the 30 invention is not limited to these specific temperature ranges. Temperatures slightly higher or lower than either the 'ideal' temperature of 45+3 C, the 'Too Hot' temperature of 65+ 3 C or the 'Overheated' temperature of

85+3 C would also be effective providing the three temperature ranges are not close to one another and do not overlap. 5 Referring to Figure 6, there is shown apparatus 23 used for screen-printing heat-sensitive dye onto the surface of the bag 2. Figure 6 specifically shows the apparatus used for screen-printing the spots 22 onto the surface of the bag 2 although it should be appreciated that similar 10 apparatus is used for printing the heat-sensitive dye in the layout of the words at positions 18, 20 on the surface of the wheat bag 16. Two methods are available for screen-

printing the dye onto the bag 2, i.e. spot printing and flood printing, which are described hereinafter.

Heat-sensitive dye is printed on to fabric 26 of the wheat bag 16 or bag 2 via a rotary screen 28 which rotates in a direction as indicated by arrow Y. The fabric 26 is supported by a rubber conveyer belt 24 which moves in a 20 direction as indicated by arrow X relative to the rotary screen 28. The conveyer belt 24 maintains the fabric 26 in a flat configuration during printing and at a constant speed as it passes underneath the screen 28.

25 The rotary screen 28 consists of a nickel mesh tube having a print pattern thereon which consists of apertures or gaps 32 in the surface of the mesh through which the heat-

sensitive dye may pass onto the fabric 26. A binder substance is first added to the theremochrome ink. The 30 binder is called a screen binder or colourless plastisol ink, and is a colourless promoter. It is usually used with standard inks and colours, but also works well with the thermochrome or heat-sensitive ink. Once mixed with the

thermochrome, the binder forms a smooth paste ready for screen printing although the shelf life is short once mixed so one should only mix a batch which is to be used.

The binder may be obtained from Flexible Products Europe 5 (UK) or Quality Colours London Ltd (UK).

Heat-sensitive dye in the form of colour paste 38 is provided to the inside of the rotary screen 28 under pressure via a pump 30. The pump 30 pumps the colour paste 10 38 along a tube 34 which extends along the inside of the rotary screen 28, and out through holes 36 in the tube 34.

The colour paste is then forced out through the apertures 32 in the mesh and onto the fabric 26 where it adheres.

Printed fabric 40 having wet colour paste 38 thereon is 15 then directed to a drier (not shown), stenter (not shown) and pad mangle (not shown) downstream of rotary screen 28.

The drier guarantees quick drying of the colour paste 38 on the printed fabric 40 by blowing hot air on it. The 20 printed fabric 40 can be fed through the drier in three passages. In the first two passages, an even hot air stream presses the fabric 40 on to the conveyer belt 24 thereby minimising smudging. In the third drying passage, the fabric 40 is supported by rods and pulled out of the 25 drier.

The drier has a large drying capacity since effective temperature distribution is achieved by an air circulation system. Air is sucked in to the drier via a healing medium 30 by ventilating fans which then blow air onto the printed fabric 40 at high speed by air channels and nozzles. Due to the high speed of the air, the fabric is heated and quickly blown dry. The hot air takes evaporated moisture

away to an exhaust fan which sucks out most of the moisture from the drier, and also maintains an under-

pressure which prevents loss of air circulation in the drier. The drier is provided with 80mm thick insulating plates to save energy, and openings which allow inspection and maintenance are provided. For reasons of safety, the roof of the drier is provided with explosion panels which 10 enable an instant pressure release if required. Further, if the exhaust fan stops, the drying is automatically shut off. Stentering, which is a controlled straightening and 15 stretching of the printed fabric 40, is performed by a stentering machine (not shown) at various stages of the process. Selvedges of the fabric 40 are attached to a series of pins or clips as the fabric 40 is fed through the stentering machine. As the pins are gradually placed 20 further apart, widthways, the fabric 40 is slowly and permanently drawn out to the desired width. There are different types of clip and pin attachments designed to be suitable for fabrics 40 of different thickness and fragility, and the stentering machine has electronically 25 controlled guiding systems and edge detectors for automation. The stentering machine can also be heated and used either simply to dry the fabric 40 or polymerise the printed aqueous pigment system. The printed fabric 40 passes through the stentering machine at least once.

30 Finally, the fabric 40 is fed through a pad mangle (not shown), which applies a resin/softener thereto.

1, Referring to Figure 10, there is shown the method for carrying out spot printing on the fabric 26. A standard printing ink, which may be a pink spot 100, is first applied by screen-printing using the apparatus shown in 5 Figure 6 in a series of spots at positions 22 to the fabric 26. It is possible that more than one or other colours can be used if desired depending on the colours required. Once the coloured ink(s) 100 has been printed on to the bag 2 at positions 22, a black thermochrome ink 102 10 is then printed directly thereover by the apparatus shown in Figure 6, but slightly enlarged to ensure full coverage of the spots 100.

The black thermochrome 102 has an inbuilt temperature 15 signature that makes the black colour turn colourless when the trigger temperature is reached thereby revealing the pink colour ink(s) 100 thereunder. The thermochrome ink 102 may be obtained from Matsui International Co. Inc (Japan). Referring to Figure 11, there is shown the method for carrying out flood printing. The pink spots 100 are first screen-printed onto the fabric 26 by screen printing using the apparatus shown in Figure 6. The black thermochrome 25 ink 104 is then flood printed over the entire surface of the fabric 26 thereby camouflaging the coloured print areas 100 until the trigger temperature is reached. It this temperature the thermochrome 104 turns colourless thereby revealing the surface pink colour 100 spots 22.

Either of these two methods, spot and flood printing, can be carried out using the apparatus shown in Figure 6.

Referring to Figures 7a to 7c, there are shown different views of a safety device 50 which can be used in conjunction with a wheat bag 2 as shown in Figure 9. The safety device 50 consists of a circular carrier section 52 5 and a stalk section 54 which projects transversely away from the centre thereof as shown in Figures 7b and 7c. The carrier section 52 is made of a thermotolerant plastic and is attached to the wheat bag 2 to indicate whether it is safe to use or not.

The safety device 50 is attached to a wheat bag 2 by inserting the stalk section 54 therein until the face section 52 is substantially flush with the bag 2. The stalk section 54 is designed such that the safety device 15 50 is securely fastened in position on the wheat bag 2 and can only be removed by physically cutting it off at the stalk section 54. The safety device 50 can be attached to any article that may experience a temperature variation, for example, foods, food packaging, hot water bottle, 20 cups, containers, ski, ski boot, aircraft wing etc. Referring to Figure 8a and 8b, the safety device 50 further consists of a sticker 80 made from a talc filled polypropylene. This is method of producing polypropylene 25 moulding which withstands the intensity of continued microwaves. The sticker 80 has a location keyway 56 on an edge thereof which enables easy location thereof with a protrusion 70 on an edge of the carrier section 52 as shown in Figure 7a. The sticker 80 is stuck in place on 30 the carrier section 52 by adhesive which is selected so that it does not melt at high temperatures.

The safety sticker 80, which has a white undercoat 64, is printed with a permanent fluorescent red, orange or yellow ink 62 to read the words "Too Hot" as shown in Figure 8a.

The words "Too hot" are covered with black thermochrome 5 ink 60 as shown in Figure 8b, but having a small area 62 reversed to read word "OK" in red/orange/yellow print 62 thereunder. At a temperature of less than approximately 75 C, the word "OK" 62 is visible underneath part of the words "Too Hot" as shown in Figure 8b.

The black thermochrome remains in its original black state so that "OK" 62 is visible until a temperature of approximately 75 C or over is reached, at which point the black thermochrome ink 60 becomes colourless thereby 15 revealing the words "Too Hot" thereunder in red, orange or yellow. The process is reversible since, as the temperature drops below the trigger temperature of about 75 C, the black thermochrome slowly becomes visible turning black, and the "OK" region 62 is shown once again.

20 The safety device 50 thereby indicates that the wheat bag 2 is safe or "OK" to use.

Advantages of the bag 2 reside in the application of the three different heat-sensitive dyes to the bag 2 and wheat 25 bag 16 which change from being invisible to being visible under exposure to a specific set of temperature ranges. The dyes act as warning systems to the user, informing then when the bag 2

is either at the ideal working temperature, too hot, or overheated and, therefore, 30 damaged. These safety features enable the bag 2 to be safely used, especially by children, without the risk of injury. Similarly the bag can be fitted with the safety

device 50 which serves the same safety function as the colour changing positions 18,20.

The safety device 50 also consists of thermochromatic ink 5 which changes colour upon exposure to a change of temperature. As with the positions 18, 20, it is envisaged that different temperatures can be used to trigger the colour range. The skilled technician would know how to alter the composition of the thermochromatic ink so that 10 it changed colour at a desired temperature. In this way, the words OK would become visible at a legally required safe temperature.

The reader's attention is directed to all papers and 15 documents which are filed concurrently with or previous to this specification in connection with this application and

which are open to public inspection with this specification, and the contents of all such papers and

documents are incorporated herein by reference.

All of the features disclosed in this specification

(including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, 25 except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including

any accompanying claims, abstract and drawings), may be 30 replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each

feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the 5 foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any

accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any 10 method or process so disclosed.

Claims

1. A bag filled or adapted to be filled with stuffing material, the bag comprising at least a region thereof 5 adapted to change colour upon exposure to a temperature variation.

2. A bag as claimed in claim 1, wherein the bag comprises textile material.

3. A bag as claimed in either claim 1 or claim 2, wherein the stuffing material comprises wheat, barley, rice, corn or foam material.

15

4. A bag as claimed in any preceding claim, wherein the À À À bag is filled, or adapted to be filled, with at least one À À. smaller bag, said smaller bag being filled or adapted to be filled with stuffing material...CLME: À: I 20

5. A bag as claimed in any preceding claim, wherein the .. temperature variation comprises a temperature increase À. from a first temperature range to a second temperature À range. 25

6. A bag as claimed in claim 5, wherein the temperature increase is effected by heating the bag in an oven, microwave oven, or the like.

7. A bag as claimed in any preceding claim, wherein the 30 temperature variation comprises a temperature decrease from the second temperature range to first temperature range.

8. A bag as claimed in claim 7, wherein the temperature decrease is effected by allowing the bag to cool.

9. A bag as claimed in any preceding claim, wherein the 5 region of the bag that changes colour changes colour on sensing a temperature variation of the contents of the bag.

10. A bag as claimed in any of claims 5 to 9, wherein the lo at least one region is a first colour when in the first temperature range and a second colour when in the second temperature range.

11. A bag as claimed in claim 10, wherein the at least one .. 15 region changes from the first colour to the second colour À À . when heated from the first temperature range to the second À À. temperature range.

À

12. A bag as claimed in either claim 10 or claim 11, À 20 wherein the at least one region changes from the second À.. colour to the first colour when cooled from the second : temperature range to the first temperature range.

À

13. A bag as claimed in any preceding claim, wherein the 25 at least one region is on an internal and/or an external surface of the bag.

14. A bag as claimed in any preceding claim, wherein the at least one region comprises a plurality of spots or 30 dots.

15. A bag as claimed in claim 14, wherein the plurality of spots are located over a majority of, or over substantially the entire outer surface of, the bag.

5

16. A bag as claimed in any of claims 10 to 15, wherein, the first colour is a colour which is substantially the same as the colour of the bag, for example, a dark colour.

17. A bag as claimed in any of claims 10 to 16, wherein lo the second colour is a colour which is substantially dissimilar from the colour of the bag.

18. A bag as claimed in any of claims 5 to 17, wherein the first temperature range is approximately less than 45 C A.. 15 and the second temperature range is greater than À approximately 45 C.

Àe

19. A bag as claimed in any of claims 10 to 18, wherein the at least one region is the first colour when in the À

20 first temperature range and the at least one region is the Àe À second colour when in the second temperature range.

I À 20. A bag as claimed in any preceding claim, wherein the at least one region is arranged to spell a warning, for 25 example, "Too Hot".

21. A bag as claimed in any of claims 5 to 20, wherein the first temperature range is less than approximately 65 C and the second temperature range is greater than 30 approximately 65 C.

22. A bag as claimed in any preceding claim, wherein the at least one region is arranged to spell the warning "Over-heated" or some other suitable warning signal.

5

23. A bag as claimed in any of claims 5 to 22, wherein the first temperature range is less than approximately 85 C and the second temperature range is greater than approximately 85 C.

10

24. A bag as claimed in any of claims 10 to 23, wherein the at least one region does not change from the second colour to the first colour when the temperature varies from the second temperature range to the first temperature range. .. 15 À À À

25. A bag as claimed in any of claims 10 to 24, wherein À the at least one region remains the second colour once : exposed to the second temperature range.

À: Àe.e À 20

26. A bag as claimed in any preceding claim, wherein the À. bag comprises at least one region as defined in any preceding claim.

27. A bag as claimed in any preceding claim, wherein the 25 bag comprises at least one region as claimed in any of claims 1 to 19 and a smaller bag comprises at least one region as claimed in any of claims 20 to 26.

28. A bag as claimed in any preceding claim, wherein the 30 at least one region comprises thermochromatic ink or dye which changes colour when exposed to the temperature variation.

29. A bag as claimed in claim 28, wherein the thermochromatic ink comprises a colour substance and a binder. 5

30. A bag as claimed in claim 29, wherein the colour substance comprises thermochrome.

31. A bag as claimed in either claim 29 or claim 30, wherein the colour substance comprises black aqueous lo thermochrome.

32. A bag filled or adapted to be filled with stuffing material, the bag comprising a safety device adapted to change colour upon exposure to a temperature variation.

:.. 15

À

33. A safety device adapted to be attached to an article, À - - the device comprising at least one region which is adapted ... to change colour upon exposure to a temperature variation.

À.--.e À 20

34. A bag as claimed in either claim 32 or claim 33, À. À. wherein the safety device is adapted to be attached to the À.. bag or article.

35. A bag as claimed in any of claims 32 to 34, wherein 25 the safety device comprises a safety tag, label or button etc.

36. A bag as claimed in any of claims 32 to 35, wherein the device comprises at least one region which is adapted 30 to change colour upon exposure to a temperature variation.

37. A bag as claimed in claim 36, wherein the at least one region comprises a temperature sensitive substance.

38. A bag as claimed in claim 37, wherein the temperature sensitive substance is printed onto a surface, for example, a sheet, sticker or other suitable surface.

39. A bag as claimed in claim 38, wherein the device comprises support means adapted to support the surface on which the temperature sensitive substance is printed.

lo

40. A bag as claimed in claim 39, wherein the support means and the surface, each comprise locating means adapted to engage with each other to thereby facilitate easy location of the surface in or on the support means.

I.. 15

41. A bag as claimed in claim 40, wherein locating means À comprises a protrusion on the support means and a cut-away À-. section on the surface, said cut-away section having a complimentary shape to that of the protrusion.

Àe-.e À 20

42. A bag as claimed in any of claims 32 to 41, wherein À. À. the temperature variation comprises a temperature increase from a first temperature range to a second temperature range, and a temperature decrease from the second temperature range to the first temperature range.

43. A bag as claimed in claim 42, wherein the first temperature range is approximately less than 75 C and the second temperature range is greater than approximately 75 C.

44. A bag as claimed in either claim 42 or claim 43, wherein the at least one region is a first colour when in

the first temperature range and a second colour when in the second temperature range.

45. A bag as claimed in claim 44, wherein the first colour 5 may be substantially opaque.

46. A bag as claimed in either claim 44 or claim 45, wherein the second colour is substantially transparent.

10

47. A bag as claimed in any of claims 42 to 46, wherein the at least one region is arranged to give a suitable signal, for example, to spell the word "OK" when in the first temperature range.

A 15

48. A bag as claimed in any of claims 42 to 46, wherein À the at least one region is arranged to give a warning, for À - - example, to spell the word "Too Hot" when in the second temperature range.

À - e.e À 20

49. A bag as claimed in any of claims 44 to 48, wherein À. À. the at least one region is adapted to change from the À ace. first colour to second colour when the temperature increases from the first to second temperature range and from the second colour to the first colour when the 25 temperature decreases from the second to the first temperature range.

50. A bag as claimed in any of claims 32 to 49, wherein the at least one region which changes colour upon exposure 30 to a temperature variation, comprises a permanent ink which spells the warning signal "Too Hot".

51. A bag as claimed in claim 50, wherein the ink is fluorescent.

52. A bag as claimed in either claim 50 or claim 51, 5 wherein the warning signal is substantially covered over with a thermochrome ink or dye which changes colour when exposed to the temperature variation.

53. A bag as claimed in any of claims 36 to 52, wherein 10 the at least one region is printed or treated with ink or dye.

54. A bag as claimed in either claim 52 or claim 53, wherein the thermochrome ink is opaque when at the first :.,'.. 15 temperature range.

À I. À À.-

55. A bag as claimed in claim 54, wherein a region is left . reversed out to spell the suitable signal "OK" thereunder.

Àe.-e À 20

56. A bag as claimed in any of claims 52 to 55, wherein Àe . thermochrome is opaque when at the first temperature range À ace. thereby covering over the warning "Too Hot" leaving the signal "OK" visible.

25

57. A bag as claimed in any of claims 52 to 56 wherein, thermochrome is substantially transparent when at the second temperature range thereby revealing the warning "Too Hot".

30

58. A bag substantially as herein described with reference to, and as illustrated by, the drawings.

59. A safety device substantially as herein described with reference to, and as illustrated by, the drawings.

Àa À. t eden À bees r.e À -e