US 20040104141 A1
The invention relates to a package for goods having a bar-code (2) and a temperature indicator (3) having a contrast medium between a front wall and a base wall. According to the invention, the temperature indicator (3) is placed beside the bar-code (2) in close connection to an outer code bar (4) thereof without covering the bar-code in order to, on one hand, in a first temperature state unimpededly enable scanning of the bar-code, but, on the other hand, after changing of the colour in the contrast medium make scanning impossible, more precisely by making an outer neutral field (5) opaque. The invention also relates to a temperature indicator as such as well as a method for marking packages.
1. A package for storing goods in a preservative state in which the temperature may not pass a certain limit value, comprising, on one hand, a bar-code of the type that between two outer, light-absorbing code bars includes a plurality of intermediate and likewise light-absorbing code bars mutually spaced-apart by neutral, light-reflecting fields, outer, neutral fields being present also outside of the outer code bars, and, on the other hand, a temperature indicator, which comprises a contrast medium contained between a front wall and a base wall, which medium in a first temperature state is transparent or light reflecting, but which upon transition to another temperature state is triggered insofar as the same is irreversibly converted to an opaque or light-absorbing colour, wherein the temperature indicator is located beside the bar-code in close connection to one of the outer code bars thereof without covering the bar-code, in order to, on one hand, in the first temperature state thereof unimpededly enable scanning of the bar-code, but, on the other hand, after triggering make scanning impossible, more precisely by making an outer, neutral field opaque or light absorbing.
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8. A temperature indicator for packages intended for storage of goods in a preservative state in which the temperature may not pass a certain limit value, comprising a contrast medium contained between a front wall and a base wall, which medium in a first temperature state is transparent or light reflecting, but which upon transition to another temperature state is triggered insofar as the same is irreversibly converted to an opaque or light-absorbing colour, the indicator consisting of a label-like unit, which along at least one edge portion unimpededly enables transmission of infrared light through the front wall in said first temperature state, but prevents such transmission in said second state.
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14. A method for marking a package (1) for storing goods in a preservative state in which the temperature may not pass a certain limit value, comprising the steps of providing the package with a bar-code of the type that between two outer, light-absorbing code bars includes a plurality of intermediate and likewise light-absorbing code bars mutually spaced-apart by neutral light-reflecting fields, outer, neutral fields being present also outside of the outer code bars, and applying a temperature indicator, which comprises a contrast medium confined between a front wall and a base wall, which medium in a first temperature state is transparent or light reflecting, but which upon transition to a predetermined second temperature state is triggered insofar as the same is irreversibly converted to an opaque or light-absorbing colour, said temperature indicator being placed beside the bar-code in close connection to one of the outer code bars thereof without covering the bar-code.
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 In FIG. 1, numeral 1 generally designates a package for goods, preferably in the form of a package for frozen goods, which in the example has a parallelepipedic, flat basic shape. In practice, the package may consist of a capsule of comparatively stiff board or cardboard. On one of the part surfaces of the package, in this case a long-side edge surface, a bar-code 2 as well as a temperature indicator 3 according to the invention are applied. The bar-code 2 may consist of a conventional price code and/or weight code (goods code), which may be printed on the package in connection with the same generally being provided with printing. Alternatively, the bar-code 2 may be included in a piece of tape, a label or the like which is applied to the package afterwards. By scanning in an available code scanner, the bar-code enables the usual data capture in a computer system of a shop.
 As is seen in the enlargements in FIGS. 2 and 3, the bar-code 2 includes a plurality of code bars located between two outer bars 4, said bars having various thickness and location relative to each other. Together said code bars form an elongate, rectangular configuration. Under the code bars, there is usually also a numerical series of Arabic figures, which in the example are designated “X”. In the area outside the two outer code bars 4, neutral fields 5 without text and pictures are left in order to enable scanning according to the prevalent bar-code technique. In practice, said fields should have a width of at least 2.7 mm. The code bars 4 may have a black, blue or another dark colour, while the fields 5 positioned between and outside the code bars may have a white, yellow or another light colour. The essential thing in this connection is that a contrasting effect is attained by the infrared light of a code scanner either being absorbed or reflected by the different colours.
 The temperature indicator in its entirety designated 3, which is shown on an enlarged scale in FIGS. 2 and 3, has general similarities to the temperature indicator known by SE 0001069-4 in as much as it comprises a contrast medium generally designated 8 contained between a front wall 6 and a base wall 7, which has a certain colour or light-reflecting property in a first temperature state, and is arranged to be irreversibly converted to a different colour or light-reflecting property when passing to another temperature state. However, as will be seen below, the present temperature indicator has another structure than the previously known indicator.
 The two walls 6, 7 are included in an outer casing 9 which confines the contrast medium 8 and which may be realized in the form of a label or label-like unit applicable to the outside of the package. Said label may have an elongate, rectangular basic shape, and be manufactured from a partially transparent film web, which is double-folded along a first short-side edge 10 and welded at the other edges as is outlined at 11, 12 and 13. Thus, when having the rectangular shape, the film is welded along two long-side edges 12, 13 and the short-side edge 11 that is opposite the double-folded edge 10. The front wall 6 includes transparent as well as opaque fields. More precisely, a transparent, comparatively narrow field 14 is arranged adjacent to the edge 10, while the remaining surface is covered by or consists of an opaque field 15. In said opaque field 15, there is, however, also a number of transparent symbol fields 16, which in the example are in the form of letters (which together forms the word STOP). On the back side of the base wall 7, which is to be applied against the surface of the package, there may advantageously be a layer of adhesive (not shown).
 The front wall 6 should have a light, e.g. white or yellow colour in order to reflect infrared light. For the same reason, the front side of the base wall 7 should have a light colour. Alternatively, the base wall may be transparent.
 The contrast medium 8 includes two different liquids, a first one of which is designated 17 and is denominated indicator liquid. The second liquid is designated 18 and is included in one or more burstable capsules 19, which are at least partially surrounded by the indicator liquid 17. By those skilled in the art the liquid 18 is denominated phase-changing liquid. Characteristic of the liquids 17, 18 is generally that they have different freezing points or eutectic temperatures. At least one of the liquids, viz. the phase-changing liquid 18, contains water and one or more freezing-point lowering agents. In addition, the liquid 18 contains a colouring agent. Suitably, the liquids may consist of water only, although also alcohol could be included. According to a preferred embodiment of the invention, a salt of the type that is approved for use in foods is used a freezing-point lowering agent. Advantageously, the agent in the respective liquid may consist of a mixture of at least two salts, such as chlorides and sulphates of calcium, potassium and sodium, respectively. Particularly, a mixture of sodium chloride (NaCl) and sodium sulphate (Na2SO4) is preferred, the eutectic temperatures of which in mixture with water can be established in a simple manner by varying the amount of salt in the water. Thus, in a mixture of H2O, NaCl and Na2SO4 the eutectic temperature may be set with high accuracy within the temperature range of −1° C. to −21° C. The desired temperature value for frozen foods is usually −18° C. In these circumstances, the eutectic temperature in the indicator liquid 17 may be set at −14° C., while the eutectic temperature for the phase-changing liquid 18 is set at the higher value −12° C.
 In the same way as in the known temperature indicator according to SE 0001069-4, the outer casing 9 is made of a material that resists low temperatures without becoming brittle or in another way degradable. At the same time, the burstable casing(s) or inner envelope(s) 19 is made of a film material that preserves a fundamental elasticity or softness at degrees above zero, but becomes brittle and degradable at lower temperatures. When a goods contained in the package 1 is frozen down, the following takes place in the temperature indicator: As the temperature falls from room temperature, heat is transported from the liquids 17, 18 via the respective casings out into the cooled environment. When the temperature in the phase-changing liquid 18 falls, the volume of the liquid decreases at the same time as the volume of the individual casing 19 decreases, the material in the casing becoming more brittle. When the temperature has fallen to −12° C., the liquid 18 freezes to ice and begins to expand. Somewhat later (at −14° C.), also the liquid 17 begins to freeze to ice and to expand. When the ice expands inside the capsules 19, the capsules crack, whereby an irreversible communication path to the ice/liquid 17 arises. The ice formed by the indicator liquid 17 can expand without the outer casing 9 being damaged or affected, since the material in said casing preserves the softness and tightness thereof at a considerably lower temperature than the capsules. On this occasion, i.e. as long as the temperature is below −12° C., no reaction takes place between the liquids 17, 18 because the same are in the state of ice. The temperature indicator is now primed.
 If the temperature indicator 3 on a later occasion would unintentionally come to be thawed by being exposed to temperatures above −12° C. during a marked time, initially the ice mass 17 and then the ice mass 18 will melt and return to the liquid state. By the fact that the capsules 19 have cracked on the occasion of freezing, the liquid 18 can leak out into the liquid 17 and colour the same because the liquid 18 contains a colouring agent. Said colouring agent may in practice consist of pigments, e.g. pigments of the type that are approved for use in foods. It is also feasible to provide the requisite colouring of the liquid 17 by a chemical reaction between the liquids. Thus, the initially transparent state of the liquid 17 is altered, in a manner known per se, to an opaque, dark coloured state. This change of state is not reversible and will subsist also if the package and the contents thereof are frozen down again.
 The described course of thawing is illustrated graphically in FIG. 6, the presumptions being that the indicator liquid has a freezing point of −14° C. and the phase-changing liquid 18 a freezing point of −12° C. During thawing, the temperature in the indicator will rise linearly from −18° C. to −14° C. during the time T1 up to phase F1. The indicator then contains only ice. During the time T2, the outer ice mass 17 melts to liquid and during this time, the temperature is constantly −14° C. up to phase F2. Then the temperature rises linearly to −12° C. during the time T3 up to phase F3. During the time T4, the ice mass in the capsules melts and the temperature indicator begins to change colour during phase F4. In a fifth phase F5, the entire contents in the temperature indicator has melted to liquid, the indicator being triggered so far that the indicator liquid has been coloured.
 If the temperature indicator would be exposed to a temperature rise up to the phase F3, and then be frozen again to a temperature below −14° C., the indicator will return to an untriggered, uncoloured state. If the exposure passes the phase F3, the indicator will entirely or partly be triggered depending on how far the phases F4 and F5 are driven.
 In practice, it is ensured that the volume of the phase-changing liquid 18 is considerably smaller than the volume of the indicator liquid 17. In this way, it can be guaranteed that the capsules in the untriggered state do not become ocularly perceptible, in particular if they have the same colour or light-reflecting property as the rest of the base wall. It is also feasible to place the capsules outside the rectangular transparent fields 14, 16. However, after triggering, the coloured, dark liquid 17 will distinctly appear via the transparent fields 14, 16. This results in that scanning of the bar-code 2 is prevented because the surface section 14 covers the neutral, light field 5 outside the outer code bar 4. Because said area after triggering of the temperature indicator has become dark, the prevalent bar-code technique makes scanning impossible. At the same time, the human eye can observe that the goods has become obsolete by thawing, in that a warning symbol in the form of the word STOP clearly appears in the front wall of the temperature indicator, as shown in FIG. 3.
 As long as the temperature indicator is primed, but not triggered, as shown in FIG. 2, conventional code scanning may be carried out without in any respect being made more difficult because the temperature indicator does nowhere cover the bar-code.
 In FIG. 5, an alternative embodiment of the temperature indicator is shown according to which an optical fibre element 20 is arranged at the edge of the indicator that is turned to the bar-code. This optical fibre element is transparent or light reflecting as long as the contrast medium 8 is transparent or light reflecting, but when the indicator is triggered the same becomes opaque or light absorbing in order to make scanning of the bar-code impossible by covering the field 5.
 In practice, the temperature indicator should be placed with the short-side edge thereof within a distance of 0-3 mm, suitably 0.2-2.0 mm, from the outer code bar 4 of the bar-code 2.
 The invention is not solely limited to the embodiments described above and shown in the drawings. Thus, the invention is applicable not only to such packages that contain frozen foods. In the packages may, for instance, medicines, photographic films, etc, be contained. Furthermore, it is feasible to utilize the temperature indicator according to the invention in order to detect/register whether freezing rather than thawing has taken place. Thus, in practice, the temperature indicator could be utilized on cans for paint. Paint is frequently water-based and thereby affected by freezing. If a temperature indicator is applied, for instance, on the outside of a lid, it will indicate-if the container/the package has been exposed to disallowed temperatures. This takes place by the phase-changing liquid in the temperature indicator bursting and colouring the indicator liquid if the temperature is lowered below an allowed value from 0° C. and downwards. Furthermore, the front wall 6 exposed outwards may be thicker than the base wall 7 in order to obtain a greater heat insulation capacity than the base wall. By said increased heat insulation capacity, it is attained that the temperature in the indicator liquid 17 does not immediately rise already as a consequence of a brief contact between the temperature indicator and a hand that seizes the package. Furthermore, the temperature indicator may include a varying number of capsules having a phase-changing liquid. In this connection, it should also be mentioned that the confinement and the delimitation of the phase-changing liquid in relation to the indicator liquid may be realized in many other ways, e.g. by the phase-changing liquid being encapsulated in a plurality of small, mutually spaced-apart balls or bubbles.
 In the drawings:
FIG. 1 is a perspective view of a package according to the invention, a temperature indicator being shown applied beside a bar-code on a long-side edge surface of the package,
FIG. 2 is an enlarged front view of the bar-code and the temperature indicator, the temperature indicator being shown in an unaffected or primed state,
FIG. 3 is an analogous front view showing the same temperature indicator in a triggered state,
FIG. 4 is an exaggerated enlarged cross-section through a first embodiment of a temperature indicator according to the invention,
FIG. 5 is an analogous cross-section showing a second, alternative embodiment of the temperature indicator, and
FIG. 6 is a chart showing the function of the temperature indicator in different temperature states.
 In a first aspect, this invention relates to a package for storing goods in a preservative state in which the temperature must not pass a certain limit value, comprising, on one hand, a bar-code of the type that between two outer, light-absorbing code bars includes a plurality of intermediate and likewise light-absorbing code bars mutually spaced-apart by neutral, light-reflecting fields, outer, neutral fields being present, also outside of the outer code bars and, on the other hand, a temperature indicator, which comprises a contrast medium contained between two walls, which medium in a first temperature state is transparent or light reflecting, but which at transition to another temperature state is triggered in so far as the same in an irreversible way is converted to an opaque or light absorbing colour.
 Deep-frozen foods are handled in large amounts in the food sector. During the time between production, when the goods are deep-frozen, and the retail sale to the final consumer, it is of vital importance that the temperature of the package and the goods contained therein does not exceed a certain recommended desired value, which for deep-frozen products usually is −18° C. If the goods during a certain time unintentionally would obtain a higher temperature than the recommended desired value, it is risked that the quality of the goods is deteriorated and if the exposure to the higher temperature would become long, the goods may become directly unhealthy by growth of bacteria. The handling of the goods from the producer to the consumer includes in practice a plurality of different phases, such as storage (long term as well as short-term storage), transshipments, transports as well as handling in the shop. There are per se strict rules and recommendations how the temperature of the goods should be supervised and documented during these different phases, but in practice the rules are difficult to completely observe. If the individual article at some point by misadventure or otherwise would be exposed to a higher temperature than the recommended highest desired value, neither the consumers nor other parties in the chain between the producer and the consumer have previously been able to see this on the package itself.
 With the purpose of managing the above-mentioned problems, it has, by SE 0001069-4, been proposed to provide packages for cooled or frozen goods with a temperature indicator comprising means, which has a certain property when the temperature of the goods is lowered towards and past a predetermined limit value which is at least somewhat higher than the desired value of temperature of the goods in question, but which alters said property in an irreversible way if the temperature during the storage would rise above the desired value up to and past the limit value. In practice, said means consists of a contrast fluid which is initially transparent and preserves the transparency thereof during temperature reduction past said limit and desired values, but is converted to an irreversible opaque state if the temperature would increase above the desired value. In SE 0001069-4, it is disclosed how the temperature indicator in question may be applied onto a bar-code exposed outside an external surface of the package in order to at least partially cover the same. The intention with this is that the temperature indicator in the transparent state thereof should enable scanning of the code, but in a triggered, opaque state make conventional scanning of the code impossible. During the development of the temperature indicator which is the subject of SE 0001069-4, it has, however, turned out that the normal scanning of the bar-code, i.e. scanning of fully useful goods on the packages of which the temperature indicator has not been triggered, is made more difficult in spite of the fact that the medium in the temperature indicator is still transparent.
 Bar-codes of the type that are applied to packages of foods and other commodities consists in general of so-called EAN codes, where the letters EAN stand for European Article Number. This constitutes a worldwide system for article numbering of all types of consumer goods. The system is administered by “International Article Numbering Association, EAN”, which issues instructions for the users which are associated to the system. EAN is used in shops having computerized paydesks and a stationary or mobile bar-code scanner. When the symbol is scanned, a registration of the EAN code takes place in the computer system of the shop. The most common bar-codes consist of price codes and weight codes, respectively. When registration takes place a row of measures are triggered if a code is in the price memory of the computer system. The price and the merchandise description that the shop has entered into the computer system are shown for the customer through a price window. The information is printed in plain text on the receipt of the customer and the computer adds the amount that shall be paid. At possible price changes, the goods do not need to be remarked. Furthermore, by using special programs in the computer system, there is a possibility to effectively assemble information which may be compiled in order to form a basis for order quantities, composition of class of goods, pricing, etc. The system could also be utilized for registering whether frozen goods has thawed, namely if the packages of the goods are provided with temperature indicators, which are combined with the bar-code of the packages. However, a condition for a symbol scanning and computer system of a shop to be used in practice is that the symbol scanning and registration becomes reliable, quick and correct. If a covering temperature indicator would delay the symbol scanning operation, e.g. by causing repeated re-scans, the possibility becomes less interesting.
 In this connection, it should be pointed out that the code scanners on the market makes use of infrared light which illuminates the bars as well as the intermediate neutral fields of a bar-code, the contrast between the bars and said fields is crucial for the quality of scanning. In larger scanners the bars are illuminated by a grid of light rays. If the bars are of a dark colour, such as black or blue, at the same time as the neutral fields are light, e.g. white or yellow, an optimum contrasting effect is obtained. However, also other combinations of colour may exist. The essential thing is that the infrared light is either absorbed or reflected by the colours in question. Of large importance is naturally also the distinctness of the code bars.
 The present invention aims at obviating the code scanning problems that are associated with the package according to SE 0001069-4 and at providing an improved package. Thus, a primary object of the invention in a first aspect is to provide a package for goods having a bar-code as well as a temperature indicator, which can separate useful goods from unusable without aggravating the scanning of a bar-code by means of conventional, existing scanning equipment. This object is attained by the features defined in the characterizing clause of claim 1. Preferred embodiments of the package are furthermore defined in the dependent claims 2-7.
 In a second aspect, the invention also aims at providing a new temperature indicator particularly suitable for the package according to the invention. An important object in this respect is to provide a temperature indicator that may cooperate with arbitrary bar-codes, e.g. such bar-codes that already are separately printed on different packages. The features of this temperature indicator are evident from claims 813.
 In a further aspect, the invention also aims at providing a method for marking packages for goods. The features of this method are defined in claims 14-15.
 By DE 19912529, a temperature indicator is previously known in the form of a label applicable on packages for goods, which in addition to a thermally reactive layer having a variable colour includes a transparent top coat in which a bar-code is integrated. As long as the goods in question holds the desired temperature, the reactive layer remains unaffected and the bar-code scannable, but if the desired temperature is exceeded, the lower layer changes its colour and makes the bar-code unscannable. However, a disadvantage of said label is that the same is intended to form the individual price or weight code of the package for goods, which means that an extremely large number of different labels have to be manufactured, distributed, stored and applied to the thousands of different articles which are in circulation in the convenience goods trade and which call for individual code marking.
 The present invention is based on the understanding that for the scanning of a bar-code not only neutral fields between nearby bars in the code or the symbol is required, but also fairly wide, neutral fields beside the bar-code, i.e. outside the two outer bars. By placing the temperature indicator beside the bar-code, although in close connection to one of the outer code bars thereof, it is guaranteed that the temperature indicator cannot disturb the scanning by entirely or partly overlapping the bar-code. As long as the temperature indicator is more or less distanced from the bar-code, a distinct contrasting effect is always obtained at normal scanning of saleable goods between the bars and the untriggered temperature indicator.