EP2904361A1

EP2904361A1 - Display device

Info

Publication number: EP2904361A1
Application number: EP13767007.1A
Authority: EP
Inventors: Philipp Wötzer
Original assignee: Innorese AG
Current assignee: Schubro Labels Ag
Priority date: 2012-10-01
Filing date: 2013-09-30
Publication date: 2015-08-12
Also published as: US20150260584A1; AU2013326675B2; US10571341B2; PE20150952A1; SA515360219B1; CA2886912A1; BR112015007263A2; JP2015537192A; ZA201502995B; WO2014053435A1; AR092754A1; RU2015116813A; BR112015007263B1; MX2015004090A; RU2640093C2; CU20150030A7; MY174733A; AU2013326675A1; TN2015000122A1; JP6318159B2

Abstract

The present invention relates to devices for displaying the previous history of products, e.g. in relation to the development of temperature. The device according to the invention comprises a surface layer, an indicator layer, an activator layer and an optional delaying layer. Heating releases moisture which migrates in some embodiments first into the delaying layer and then into the activator layer. Here, an activator is mobilized and migrates together with the humidity into the indicator layer. A colour change occurs as a result of the interaction of the indicator with the activator in the presence of moisture, which change indicates that the critical temperature has been exceeded. The present invention further relates to a method for producing the device according to the invention and to applications of said device, e.g. in monitoring the temperature of sensitive products.

Description

display device

1. Technical area

The present invention relates to display devices, and more particularly to devices for detecting and displaying the thermal history of refrigerated goods, and in particular frozen products. It also relates to processes for their preparation and the application of the devices according to the invention in monitoring the thermal history of refrigerated products and Tiefkiihlprodukten particular.

2. State of the art

Devices for reporting the history of products (also referred to as "temperature-time indicators") indicate whether the product's cold chain has been interrupted, ie, whether the product has exceeded a critical temperature for a relevant period of time for frozen products of interest, in this case, the device indicates whether the product could warm to a temperature above the critical temperature of 0 ° C.

There is a great need for such displays, since the interruption of the cold chain, the desired product quality can not be guaranteed. For example, there is a risk of uncontrolled frozen foods. Bacterial growth during an interruption of the frozen chain. Such bacterial growth can pose significant health risks for the consumer.

In view of this need, there have been and are many efforts to develop appropriate temperature-time indicators. Here, by way of example, the display device according to WO 2007/045424 and the time-temperature indicators OnVu ICE of BASF and indicators Timestrip in 40549 Dusseldorf be mentioned.

However, the known from the prior art time-temperature indicators are not able to reliably indicate interruptions of the cold chain. On the one hand, there is the risk that a short-term warming of the packaging (eg due to the hype of the consumer in the supermarket) leads to a false-positive display. On the other hand, the risk exists in the time-temperature indicators of the prior art that an interruption of the cold chain is not indicated as such, if there is air between the refrigerated goods and the display device within the package. Another problem that occurs, for example, in the commercial indicator of the company Timestrip, is the uniformity of the displayed color change (ie, the constant time between reaching a critical temperature of the indicator and color change - regardless of the nature of the goods to be cooled). Such uniformity is undesirable because some frozen products thaw significantly faster than others. A reliable ad should consider such differences.

3, Summary of Invention

In view of the above-mentioned problems of the time-temperature indicators known from the prior art, it is an object of the present invention to provide a time-temperature indicator which reliably indicates cold chain interruptions without false-positive indications in which interruptions of the cold chain are reliably displayed, even if there is air between the refrigerated goods and the display device. Furthermore, the display of the indicator according to the invention should take into account the actual thawing speed of the refrigerated goods.

This object is achieved by the device according to the following claim 1. Preferred embodiments of this device are characterized in the following claims 2-10.

The present invention further relates to methods for producing the display devices according to the invention. These methods are characterized in the following claims 11-13.

Finally, the present invention also relates to packages for frozen products as described in the following patent claim 14, as well as the deep-frozen products comprising this package according to the following claim 15.

4. Description of the drawings

Figure 1 illustrates the layer sequence of the device according to the invention in its simplest embodiment.

FIG. 2 shows the layer sequence of the device according to the invention in a further embodiment with adhesive layers.

FIGS. 3 to 13 illustrate the layer sequences of further devices according to the invention. The reference numerals used in the figures have the following meanings;

1-coat layer (a)

2 - indicator layer (b)

3 - activator layer (c)

4 - delay layer (d)

4 ⁴ - Retardation layer (d) as part of the product packaging

5 - upper adhesive layer

6 - middle adhesive layer

7 - lower adhesive layer

8 - separating layer

5. Detailed description of the invention 5.1. definitions

The term "indicator" in the context of the present invention refers to a substance which, upon interaction with the activator (chemical or physical reaction), changes its visual appearance, in particular comprising a color change, the colors (including colorless) before and after the color change are not fixed.

The term "activator" in the context of the present invention refers to a substance which is suitable, by interaction with the indicator, to bring about a change in the optical appearance of the indicator.

The suitability of a substance as an indicator or activator in the context of the present invention depends on the identity of the respective reaction partner. Thus, the fulfillment of the criterion "indicator" is always to be considered in connection with the fulfillment of the criterion "activator" (and vice versa). The suitability of the indicator also includes the presence of the indicator in a form suitable for reaction with the activator, eg, the presence of a pH indicator in the protonated form when the activator is a base, or the presence of a pH indicator in the deprotonated form if the activator is an acid.

In the context of the present invention, the indication of the "time between the start of thawing and color change" (in this application also with &Quot; turnover period ") refers to the period of time which can be measured to the color change detectable to the naked eye when a product of frozen peas (300 g, frozen temperature - 18 ° C, standard package, no film inside, only artonum packaging 320 g / m ² ) in a room temperature environment (wooden table below, side and top air, each tempered to + 20 ° C) is brought.

The turnaround time is essentially determined by the "total delay effect" of the "relevant layers". The "total retardation effect" refers to the amount of time it takes for a color change sufficient amount of moisture to migrate from the chilled goods through all the relevant layers to the top working layer. In this context, the term "relevant layers" refers to all layers of the device according to the invention from the lowest layer up to and including the uppermost coloring layer, and the product packaging below the device according to the invention is also a relevant layer determining the entire delay effect it is not known that the determination of the overall retarding effect is to be based on the use of a 320 g / m ² carton.

It is an essential characteristic of the device according to the invention that it is dry before the ingress of moisture from the chilled goods. "Dry" in this context means a content of moisture which is so low that the color reaction which leads to the desired color change, This applies in particular to the storage conditions to be expected, eg when the device according to the invention is stored at 25 ° C. and <5% relative atmospheric humidity over a period of 2 months, preferably 6 months no visible to the naked eye color reaction when storing the inventive device at -18 ° C and 100% relative humidity over 12 months, preferably 24 months instead.

Unless otherwise determined in the present application, the ones used herein

Terms generally understood in the art, such as those described e.g. from relevant dictionaries, dictionaries and encyclopaedias.

Basis weights of paper and cardboard refer to basis weights according to DIN 6730.

In the case of films, they refer to basis weights in DIN 53352. Strength specifications for films refer to DIN 53370. 5.2. overview

Surprisingly, it has now been found that by heating of frozen products on

Temperatures above 0 ° C in the packaging moisture migrated in sufficient quantity through the packaging of the frozen products in order to trigger chemical reactions on the outside. This finding takes advantage of the present invention to indicate over-freezing heating; When it is heated above freezing, partial thawing of the chilled product releases moisture. A portion of this moisture migrates through the package to the display device of the invention. The moisture penetrates into the device according to the invention. There indicator and / or activator are solubiiisiert or mobilized by the moisture. As a result, the previously spatially separated components indicator and activator are guided to each other. When these two components meet, a chemical or physical reaction takes place, which leads to a color change. This color change is used to indicate the warming of the product to a temperature above the temperature at which the chilled goods begin to thaw.

The sensitivity of the device according to the invention can be increased by using materials with particularly pronounced hygroscopicity (for example as matrix material of the indicator and / or activator layer explained in more detail below). However, this measure is limited by the required storage stability. Especially hygroscopic materials will "draw" a large amount of moisture even with short shelf life under moderate humidity conditions, causing an unwanted premature color reaction.

The operation of the device according to the invention is based on the released during thawing of the refrigerated moisture. Consequently, it is neither necessary nor provided for in the device according to the invention that moisture reservoirs are present in one or more of the layers of the device according to the invention.

The required duration of exceeding the minimum thawing temperature of the goods to be cooled to the color change can be adjusted by a suitable choice of the layer materials used or their thicknesses.

The device according to the invention is characterized in that no adaptation of the underlying product packaging is necessary (if it consists of cardboard or other moisture permeable material). In particular, no opening in the product packaging and no "wick" through the product packaging is required. Another essential aspect of the present invention is the possibility of producing the device according to the invention in layers by means of a common printing process, such as, for example, offset or flexographic printing processes.

5.3. layer sequence

As explained above, the present invention is based on a spatial separation of indicator and activator by providing these components in separate layers.

Further essential elements of the device according to the invention are a cover layer (1), which protects the device from moisture to the outside atmosphere, and a retardation layer (4), which regulates the moisture transport from Kühlgut to Aktktivator- and Indikatorscliicht. The retardation layer may also consist of the product package to which the device is applied. In this case, can be dispensed with a separate delay layer. All other layers are not absolutely necessary for the proper functioning of the device and therefore optional. In its simplest embodiment, the device according to the invention is therefore characterized by the following layers. The sequence of layers given below (starting from the side remote from the item to be cooled) represents a preferred embodiment of the apparatus according to the invention:

(a) topcoat (1);

(b) indicia layer (2);

(c) activator layer (3);

(d) optional retardation layer (4).

However, this layer order is not essential to a successful implementation of the invention. Only the following boundary conditions with respect to the sequence of shots have to be fulfilled:

(i) The topcoat must be farthest from the chilled product in relation to the indicator, activator and retarder layers;

(ii) At least the indicator layer must be further away from the refrigerated goods than the delay layer that may be present.

Thus, in the case of the presence of the retardation layer, the position of the activator layer may be between the cover and indicator layers, between the indicator and retarder layers, or below the retardation layer. Thus, the result the following other layer orders in addition to the above layer order (l) ~ (2) - (3) - (4): (l) - (3) - (2) - (4) and (1) <2) 4 (3).

Other optional layers can be introduced as far as this is the invention

Function not impaired. In particular, the following further layers can be provided:

Adhesive layers (5, 6 _» 7) can be added to ensure the cohesion of the layer sequence. In particular, it lends itself to the layer sequence shown above

• provide an upper adhesive layer (5) directly under the cover layer (1);

• to provide a middle adhesive layer (6) between indicator layer (2) and activator layer (3); and or

• Provide a lower adhesive layer (7) below the retardation layer (4).

As a further optional layer, a separating layer (8) can be provided between indicator layer (2) and activator layer (3) so as to avoid a direct contact of activator and indicator at the interface between the layers and a further possibility for regulating the activation duration up to Moreover, said separating layer (8) can simplify the production of the device according to the invention.

Other layers are also conceivable, e.g. Separating layers between other layers of the device according to the invention and / or other indicator and / or activator layers, which can cause additional color changes under certain conditions, for example. Likewise, it is not excluded that several of the layers described here provide multiple. It could, for example, be considered to provide the layer sequences described in this application two or more times over one another. Such a "sandwich construction" using two or more indicator and / or activator layers results in a gradual or gradual color change which allows one to distinguish between short and long term breaks in the cold chain.

Further essential embodiments of the present invention are characterized by the following layer series:

(a) Overcoat (1)

(oH) upper adhesive layer (5)

(b) indicator layer (2) (πιΗ) Middle adhesive layer (6)

(c) Activator Vision (3)

(d) retardation layer (4)

(uH) lower adhesive layer (5); such as

(a) Overcoat (1)

(oH) upper adhesive layer (5)

(b) indicator layer (2)

(t) separating layer (8)

(c) Activator Vision (3)

(d) retardation layer (4)

(uH) lower adhesive layer (7);

In these two Schicklitenabfolgen it is of course possible, in each case the lower adhesive layer

(7) to omit, respectively, the upper adhesive layer (5) omit or even omit both the lower and the upper adhesive layer (5, 7).

FIG. 1 illustrates the layer sequence according to one of the simplest embodiments of the present invention. Since no adhesive layers are provided in this embodiment, this embodiment is particularly suitable in cases in which the device according to the invention is to be integrated into the product package, i. In which the cover layer forms a layer of the product packaging, Alternatively, the layer sequence according to FIG. 1 could be held together by a glued-on product label. In this case, the product label must be transparent in the region of the device according to the invention. Optionally, the retardation layer is formed by or disposed on a further inner layer of the product package. By this integration of the device according to the invention in the product packaging, the desired cohesion of the layers can be ensured even without intermediate adhesive layers.

In the layer sequence according to the second embodiment, the cohesion of the layers and integrity of the device are achieved by suitable adhesive layers. This is shown in FIG. 2.

In the embodiment according to FIG. 3, the middle adhesive layer is a release layer

(8) replaced. The cohesion of the layers is ensured by a wider configuration of the cover layer (1) and the upper adhesive layer (5), which outside of Indicator layer (2) and activator layer (3) covered area allows direct contact and cohesion with the retardation layer (4). In the layer sequence shown in FIG. 3, the release layer (8) is optional, ie a further embodiment relates to the same layer sequence, but in the absence of the release layer.

FIG. 4a shows the sequence of layers of a further embodiment of the present invention. In this case, only a single adhesive layer, namely the upper adhesive layer (5), is present between cover layer (1) and indicator layer (2). The cohesion of the layers and thus the integrity of the device are ensured by a larger dimensioning of the cover layer and the upper adhesive layer (5), The above indicator layer (2), activator layer (3) and retardation layer (4) also reaching upper adhesive layer comes into direct contact with the product packaging and forms a stable adhesive bond with this. This embodiment is shown again with the optional separation layer (8).

FIG. 4b shows a variant of the embodiment according to FIG. 4a. In this variant, the delay layer (4) has been omitted,

FIG. 4c shows a variant of the embodiment according to FIG. 4a. In this variant, the separating layer (8) has been omitted.

FIG. 5a shows a variant of the embodiment according to FIG. 4a. In this variant, the retardation layer (4) is integrated in the product packaging, i. the retardation layer (4) is formed exclusively by a layer of the product package. In this case, the bonding between upper adhesive layer (5) and retardation layer (4, layer of the product package) takes place.

FIG. 5b illustrates a further variant of this embodiment. The sequence of layers corresponds to that of FIG. 5a, but the indicator layer (2) and activator layer (3) are interchanged with one another.

FIG. 6 shows a further variant of the embodiments of FIGS. 4a and 5a. In this variant, a separate delay layer (4) is present in addition to the product packaging. This layer is slightly wider than the layers above it. The cohesion of the layers is ensured by the contact between upper adhesive layer (5) and the protruding portion of the retardation layer (4). Moreover, the region of the adhesive layer (5) projecting beyond the retardation layer (4) allows the device to be fixed on the product package (which serves as an additional retardation layer (not shown in FIG. FIG. 7 shows a variant of the embodiment according to FIG. 3. In this variant, the optional separating layer 8 has been omitted. Moreover, the lower adhesive layer (7) is arranged only in the areas outside the overlying indicator layer (2) and activator layer (3). This variant also allows the use of pressure-sensitive adhesives, which have no or a very low permeability to moisture or water vapor.

FIG. 8 relates to a mold in which the activator layer (3) is arranged below the retardation layer (4). In this case, the activator migrates together with the moisture through the retardation layer (4) to the indicator layer (5).

FIGS. 9a 9b and 9c illustrate further embodiments in which the activator layer is arranged elsewhere: These embodiments correspond to those of FIGS. 4a, 4b and 4c, wherein only the indicator layer 2 and the activator pushes 3 are interchanged were.

FIG. 10 shows an embodiment according to FIG. 7, which additionally has a second activator layer (3) below the retardation layer (4) and within the regions covered by the lower adhesion layer (7). The provision of a second activator layer has the advantage that the color change takes place gradually or stepwise. It is therefore preferred in those cases where the display is intended to allow a distinction between short and longer breaks in the cold chain. Of course, a second Aktivatorschicht also on. another position, the device, e.g. between indicator layer (2) and upper adhesive layer (5),

Figure 11 illustrates another variation of the embodiments. According to Figures 4a and 9a: In the embodiment of Figure 1 1, the activator layer (3) below the retardation layer (4) is arranged. In this layer order, the

Delay layer (4) act as a release layer, and so replace the separation layer shown in. 4a and 9a.

FIG. 12 relates to a further embodiment in which the product packaging serves as a delay layer (4) and in which a separating layer (8) is provided between the indicator layer

(2) and activator layer (3) is arranged. Moreover, in this embodiment, the separating layer projects beyond indicator layer (2) and activator layer (3). This allows for direct contact between upper adhesive layer (5) and release layer (8), which contributes to the integrity of the device. Another lower adhesive layer (7) is between separating layer (8) and Product Vibration / Delay Angle (4)., So that it encloses the activator layer (3) partially or completely.

FIG. 13 shows a further embodiment of the device according to the invention. In this embodiment, two delay layers (4) are provided. A first retardation layer (4) between indicator layer (2) and activator layer (3) is formed by the product layer. This retardation layer (4) also serves as a separation layer. A second retardation layer (4) is located below the Aktivatorschi cht (3). This can e.g. a water vapor-permeable thin protective film, such as is commonly used in the interior of food packaging. The device of this embodiment can be produced particularly easily at once with the remaining product packaging.

Of course, the delay layers shown in FIG. 13 are also used in all other devices according to the present invention, provided that the invention is applied to suitably designed product packaging. In each case, the entire delay effect caused by all the delay layers, including the product packaging, must be taken into account.

The devices shown in Figures 1 to 13 (i.e., layer sequences shown and other design features) are preferred within the scope of the present invention. Particularly preferred are the devices shown in Figures 4a-c, 5a, 5b and 9a-c.

5.4. Cover layer The cover layer has the following functions:

• The top layer prevents _» moisture from penetrating to the indicator layer and / or activator layer from the outside.

• The cover layer has sufficient transparency to make a color change in the indicator layer visible from the outside.

The cover layer allows further identification of the display device according to the invention, e.g. by applying a logo,

As a cover layer, all film materials can be used, which are suitable to meet the above requirements. Here are the first two

Requirements of equal priority while being able to apply a logo is of secondary importance. Thus, all transparent films can be used, which have no or a low permeability to moisture, that this has no effect on the functionality of the device according to the invention. For example, it is possible to use cover layers in which the passage of moisture is so low that, when the device according to the invention is stored for 1 year at 25 ° C. and 75% relative humidity, the amount of moisture penetrating during this period does not have an influence on the function which is discernible to the naked eye the device has. This means that, for example, a film of polypropylene (PP) of the thickness 50 pm and more, preferably 60 um and more, can be used. Also usable are other film materials such as high density polyethylene (HDPE) with comparable water vapor permeability. For materials with lower water vapor permeability, it is of course possible to reduce the thickness of the film accordingly. Conversely, materials with a higher water vapor permeability can also be used, provided the film thickness is adjusted accordingly. Of course, it is important to ensure sufficient transparency. Another suitable film material is Polyvinyiidenchlorid, since its water vapor permeability is lower by about one order of magnitude than that of polypropylene. Biodegradable films based on starch or cellulose, which also fulfill the requirements for transparency and impermeability to moisture, can also be used.

Of course, cover layers can be used, which in turn are composed of several layers of different plastics (as far as the above requirements are met by the multi-layer cover layers).

As a further alternative, the cover layer can be formed by applying a moisture-impermeable protective lacquer. In this case, the above-mentioned requirements with regard to transparency and water vapor permeability must be set in the same way to the covering layer formed from protective lacquer. The thickness of the protective lacquer is to be adjusted accordingly. Suitable materials for the protective lacquer are silicones formed by polysiloxanes and lacquers formed by polymeric synthetic resins.

Also possible is a combination of this protective coating with the films mentioned above. In this case, of course, the combination thus formed must meet the above requirements for transparency and water vapor permeability.

Preferred cover layer is a film of polypropylene having a thickness in the range of 40-80 μm, more preferably about 60 μm. 5.5. Upper adhesive layer

The optional upper adhesive layer may be formed by any adhesive. Preference is given to using pressure-sensitive adhesives. Suitable pressure-sensitive adhesives are described, for example, in the standard work "Handbook of Pressure-Sensitive Adhesive Technology" by Donatas Satas (van Nostrand, New York 1 89), in particular adhesive acrylate, natural rubber, synthetic rubber, silicone or EVA based adhesives Preference is given to pressure-sensitive adhesives on a natural basis, such as adhesives based on casein, gelatine and starch, and hot-melt adhesives and flexographic adhesives such as Novarad® RCL-6015 from Novamelt® and other UV-curable monomer / oligomer compositions on acrylate urethane are also conceivable Base or acrylate-epoxy base.

The adhesive layer is used in a thickness of typically 5-1000 μm, preferably 10-250 μm. In particular, the abovementioned flexographic printing adhesives are typically applied in amounts of 1-50 g / m ² , preferably 5-40 gm ² , more preferably 10-30 g / m ² .

5.6. indicator layer

The indicator layer is characterized by the presence of at least one indicator. In the context of the present invention, the term "indicator" refers to any substance or mixture of substances that exhibits a color change by chemical reaction or other interaction with a suitable activator, a typical representative of these substances are the so-called pH indicators Indicators show a color change as soon as the pH changes to such an extent that a characteristic value characteristic of the respective pH indicator is exceeded, eg if the pH indicator is blue in a basic medium (pH> 7) and acidic (pH < 7) red, a color change can take place if the medium in the indicator layer is basic and an acid is used as the activator It is equally possible to use said pH indicator in an acidic medium and to use a base as an activator.

Of course, it is necessary to match the pH indicator, the surrounding environment, and the activator to ensure that the desired color change occurs upon migration of the activator into the indicator layer. For pH indicators, this may be done by appropriate choice of the pH indicator (in terms of color change pH), adjustment of the pH of the indicator layer and appropriate choice of activator.

Among the pH indicators are dyes of natural origin as well as artificial ones

Dyes. Preference is given to natural dyes which can be obtained, for example, from plants such as vegetables or fruit. These include, among others, the flavonoids such as the Anthocyanins. Preferably, in this case are the anthocyanidins. Particularly preferred is the use of cyanidin. Likewise, delphinidin, malvidin, peonidine and petunidin can be mentioned. Mixtures of dyes can also be used. However, it should be ensured that the color change behavior of the individual dyes is coordinated so that under the given conditions (presence of activator and moisture possibly in the presence of a matrix and other constituents) a clearly recognizable color change takes place.

In addition to pH indicators, other substances which have an activator-induced Farbuin.sch.lag can be used. In particular, redox indicators should be mentioned here. This is uro. Dyes that show a color change on reduction and / or oxidation. Typical examples are ferroin or methylene blue. A comprehensive list of redox indicators can be found in the English version of Wikipedia under the entry "Redox indicator" (September 2012) .Accordingly, suitable reducing agents and / or oxidants can be used as activator substances.

Another hate of suitable indicators are substances that show a color change by complex formation. A simple example of this is anhydrous copper sulphate CUSO4, white, which in the presence of moisture assumes the blue color of the complex [Cu (H20) g] SO4. In this simple case, the moisture itself acts as an activator, so that (exceptionally) can be dispensed with the Aktivatorschicht. In all cases where colored complexes with ligands other than I O are formed, the ligand in question acts as an activator and is provided in the activator layer.

Preferred indicator material are pH indicators and in particular the above-mentioned anthocyanidins and very particularly preferably cyanidin.

The indicator layer may include other optional ingredients in addition to the indicator substance. Suitable further optional constituents may in particular be selected from the following components;

• matrix materials such as agar-agar, cellulose, starch, gum arabic, guar gum, gelatin and arrowroot starch; cellulose is preferred. Also suitable is polyethylene glycol. If the device according to the invention is produced by the preferred printing method, care must be taken that the viscosity of the matrix materials used is adapted to the printing method. This can be done by suitable choice of the chain length of the polymeric matrix materials. It is also possible a homogeneous or heterogeneous mixture of the matrix material It is also conceivable to use a textile fabric or fleece with a suitable solvent of suitable viscosity. When the indicator is applied to a fabric or nonwoven, said fabric or nonwoven acts as a support rather than an indicator encircling matrix. In these cases, the material to be used for fabric or nonwoven is not subject to any further restriction (except that it is said to be inert to the indicator and activator). A suitable material is, for example, cellulose, for example a layer of a paper tissue.

• substances that set the medium to suitable initial conditions to ensure stable coloration of the indicator (before the color change); For example, when using a pH indicator and when using an acid as an activator, the medium with bases such as N ^ CC ^ NaHCC, CaO or CaC.03 can be adjusted to an alkaline pH; an acidic pH adjustment can be made with acids such as e.g. Milk, oxalic, tartaric and citric acid take place;

Hygroscopic materials, including hygroscopic polymers such as e.g.

Acrylic acid acylate polymers and hygroscopic salts such as e.g. Magnesium chloride, potassium chloride and calcium chloride, which can affect the color change (e.g., accelerate);

• salts to lower the melting point of water. The use of salts to lower the melting point of water is useful when the inventive. Device on saline refrigerated goods (e.g., pretzels.) Is used. By presenting salt in the indicator layer (as well as the further inner layers of the device according to the invention), the device according to the invention can be activated already at temperatures below 0 ° C, in which the refrigerated goods begins to thaw. Since melting point depression is a colligative phenomenon, any salts can be used. Preferred are non-toxic salts, e.g. NaCl.

Stabiiistoren, such. Potassium sorbate for mold suppression; other preservatives include calcium chloride and. ethanol; the use of such stabilizers is particularly preferred when using natural dyes.

The amount of indicator dye to be applied is typically in the range of 0.1 to 100 g / m ^2, preferably 1 to 40 gm ² _{3, more} preferably 4 to 12 g / m ² . The amount of indicator applied affects the speed and intensity of the color change. A strong paint application (ie order quantities in the upper half of the above On the other hand, a strong application of paint can complicate the drying in the Hersteilungsverfahrens. It has proved to be advantageous to apply a plurality of thin layers instead of a strong indicator layer and to dry before the respective subsequent indicator layer is applied. For example, 2-40 layers can be applied. Preferred are 4-10 layers, more preferably 6-8 layers. Of course, the ease of drying is also dependent on the composition of the pH indicator layer (eg hygroscopic properties of the constituents and water content). By appropriate adjustment of the water content, choice of the matrix material and the amount applied per shift, a desired rate of drying could be set. When using printing presses, the applied amount of indicator can be adjusted to the draw volume of the printing press.

5.7, middle adhesive layer

For the middle adhesive layer, the information in section 5.5 on the upper adhesive layer applies analogously. In the middle adhesive layer, however, ensure _"that sufficient moisture transport is guaranteed by the material to be cooled to the indicator layer.

The desired suitability for moisture transport can be achieved on the one hand by choosing suitable adhesives / adhesives. Adhesives capable of allowing moisture to pass through are particularly starch or gelatin based adhesives. By reducing the amount applied, the moisture permeability of other adhesives, which per se have lower moisture permeability (based on equal application rates), can be brought to an acceptable level. Thus, with a suitable adjustment of the order amount, a variety of other adhesives are used.

On the other hand, it is possible to provide in the middle adhesive layer pores or openings in which no adhesive is present and through which the moisture can migrate unhindered into the indicator layer. The shape and size of the openings are not specified as far as it is ensured that the total area of the openings is sufficient to ensure the moisture transport required for the desired color change.

5.8. Interface

The provision of a separating layer between indicator layer and activator layer is particularly recommended if the device according to the invention is to be produced by applying layer by layer. In this case, in the absence of the separating layer, a direct coating of the activator layer by the (still moist) material of the indicator layer could lead to a color reaction at the interface before the indicator layer has dried sufficiently. In order to avoid such a premature interface reaction, indicator layer and activator layer can be separated from one another by said separating layer, thus avoiding the premature color reaction.

The release layer must be able to absorb and store small amounts of moisture without passing them on to the adjacent layer before the subsequent drying cycle.

Before applying the next layer, the release layer must be dry. This means that the separating layer may need to be dried. The release layer can also be applied in the form of several separate layers.

With a suitable choice of the adhesive, the above-mentioned middle adhesive layer can act as a release layer. Alternatively, plastic films with suitable moisture permeability could be used. Likewise, the use of a layer formed from starch is conceivable. Particularly preferred are separating layers which are formed from gelatin or paper (cellulose). The use of a fabric or fleece is also possible. Also in this case the fabric to be used for fabric or nonwoven is not subject to any further restriction (except that it is said to be inert to the indicator and activator), cellulose is preferred. Other suitable materials for the release layer are waxes and especially low (<25 ° C) melting waxes. Fats and particularly low (<25 ° C) fats, polyethylene glycol, dextrin, casein, starch, polyvinyl alcohol, gelatin, polysaccharides such as agar-agar or pectin, and mixtures thereof.

5.9. Aktivatorschicfct

The activator is chosen so that a chemical reaction or other interaction with the indicator results in a color change. When using pH indicators, the activator is either an acid or a base. If an acid is selected, the milieu of the indicator layer must be basic (or at least more basal than the pH of the indicator). Similarly, when using a base as an activator, the milieu of the indicator layer must be acidic (or at least more acidic than the pH trans-point of the indicator). Preferred acids are oxalic acid, lactic acid and tartaric acid, citric acid is particularly preferred. When bases are used as the activator, in turn, N, CC, NaHCO 3,

CaO or CaCO 3 find use.

If redox indicators are used, the same applies to pH indicators. This means that oxidizing agents can be used as .Activators, provided that the redox indicator is in the reduced state. In this. In this case, a reducing environment in the indicator layer can stabilize the redox indicator. Conversely, it is possible to use a reducing agent as the activator if the redox indicator is present in the oxidized form. In this case, an oxidizing environment in the indicator layer can stabilize the redox indicator.

Suitable oxidizing agents include organic percarboxylic acids and metal salts such as MnO 2; Suitable reducing agents include ascorbic acid, sulfite salts and stannous salts. When choosing suitable oxidants and reducing agents, it is important to ensure sufficient stability under the given conditions, i. There must be no reaction with the other constituents of the activator layer over the intended storage period. If the device is used for foodstuffs, care must also be taken to ensure that the antioxidants and / or reducing agents used do not pose a health risk.

These substances are suitable both for use as an activator and for use in the desired setting of the milieu of the indicator layer.

Other ingredients of the activator layer are optional. For example, the matrix materials mentioned for the indicator layer can be used. Also in this case, fabrics or nonwovens can be used. Again, the fabric to be used for fabric or nonwoven is not subject to any further limitation (except that it is said to be inert to the indicator and activator). Cellulose is preferred.

In addition, a dye can be absorbed in the activator. Suitable dyes include titanium dioxide or food grade dyes. By staining the activator layer, e.g. With titanium dioxide, the contrast in the color change in the indicator layer can be increased.

Furthermore, it may be advantageous to include in the activator layer hygroscopic materials such as hygroscopic polymers (eg acrylic acid-acrylate polymers) or hygroscopic salts (eg magnesium chloride, potassium chloride and calcium chloride). The amount of activator in the activator layer is typically 0.1 to 100 g / m ² , preferably from 1 to 40 g / m ² , particularly preferably from 4 to 12 g / m ² . Also in this case it is advantageous to form the activator layer by separate application and drying of several individual layers so as to facilitate the drying. It can be used 2-30 individual layers. Preferred are activator layers formed from 3-8 individual layers, more preferably 4-6 individual layers.

5.10. retardation film

The retardation layer forms a kind of "moisture buffer" which absorbs some moisture before it is passed on to the activator layer, which has the advantage that no color change occurs due to the release of very small amounts of moisture of the indicator by the consumer.

The retardation layer is an optional component of the device according to the invention. The delay effect required for the successful implementation of the invention can also be achieved by further layers of the device according to the invention, e.g. Separating or adhesive layers can be achieved. Also to be considered is the delay effect caused by the product packaging.

Thus, the period of time from the first formation of moisture to the color change can be adjusted by suitably selecting the delay-causing layers (in terms of presence or absence, materials used and their thickness), taking into account the retardation effect of the product package. Decisive for this period of time is the overall retarding effect of all layers between product and the outermost layer relevant to the interaction (i.e., activator or indicator layer).

The materials which can be used for the retardation layer correspond to the materials mentioned under point 5.8 for the separating layer, such as e.g. Waxes. Fats, polyethylene glycol, dextrin, etc .. D.h. films having sufficient moisture permeability, a layer formed of starch or, more preferably, a layer formed of gelatin may be used.

Particularly preferred is the use of paper or paperboard (ie, a layer of cellulose), eg paper of a thickness of 25-80 g / m ² . With the use of paper, newsprint paper or paper of comparable thickness of about 40-60 g / m ² , in particular 50 g / m ² , has proven to be advantageous. If a shorter turnaround time is desired, the use of silk papicr or paper of comparable thickness of about 20-30 g / m ² , in particular 25 g / m ² may prove to be advantageous. The use of paper or cardboard is particularly preferred in cases where indicator layer and activator layer are to be laminated on each other. In these cases, in addition to achieving the desired retarding effect, the retardation layer can also serve as a carrier material for the (indicator or activator) layer which is closer to the item to be cooled.

As already mentioned, when selecting a suitable retardation layer, it is also advantageous to consider the moisture permeability of the further layers of the device up to and including the outermost coloring layer (ie indicator or activator layer) and the underlying product packaging: If one of the other layers and / or the If the product packaging has a low moisture permeability, the moisture permeability of the retardation layer should be as high as possible (or the retardation layer is omitted completely if maximum permeability is required, see below). On the other hand, if the moisture permeability of the other layers and the product package is high, a retardation layer should be used which is closer to the lower range of the above interval to set the desired time to color change.

A further embodiment of the present invention is to use only the packaging of the item to be cooled (or a layer thereof) as a delay layer, so omit the retardation layer as part of the device according to the invention. This embodiment is particularly suitable for use with product packaging, which already have a sufficiently high delay effect and / or in devices in which the other layers present (such as adhesive and / or release layers) in combination with the Produktverpaekung have a sufficiently high delay , Of course, the same product packaging requirements apply here, ie. the packaging material (or its constituent) must be able to absorb moisture and release it with appropriate delay. Cardboard packaging is well suited for this purpose. However, if the package is coated with a moisture-impermeable material, it must be ensured that this moisture-impermeable material in the area in which the device of the invention is applied, is not present or at least provided with pores. Alternatively, said moisture-impermeable material can be applied only after application of the device according to the invention, so that the moisture transport through the packaging for the device according to the invention takes place underneath the moisture-impermeable layer and is not hindered by it.

11.5. Lower adhesive layer For the lower adhesive layer, the information on the middle adhesive layer in section 5.7 applies analogously. Again, by appropriate measures (ie, choosing a suitable adhesive and / or provision of recesses) to ensure sufficient moisture transport.

12.5. Setting the time to color change

The desired period of time between the beginning of the thawing process and color change of the device according to the invention (hereinafter: "turn-over time period") is in the range from a few minutes to several hours, in particular from 10 minutes to 5 hours, preferably from 30 minutes to 4 hours, even more preferably from 1 h to 3 h and especially about 2 h.

Depending on the nature of the product group, it may be useful to develop devices according to the invention with fast color change speed, average color change speed or slow color change speed. For example, a fast color change device should discolor after about 60 minutes (e.g., in the range of 60 to 100 minutes). A device with a medium color change rate should discolour after about 90 minutes (e.g., in the range of 90 to 140 minutes). A slow color change device should discolor after about 140 minutes (e.g., in the range of 140 to 200 minutes). These data on turnover times refer to the standard test conditions according to section 5.1 above.

By the following iterative process, the time between the beginning of the thawing process and color change of the device according to the invention to the desired

Value to be set:

1. In a first step, a basic device according to the present

Description made. It is advisable to produce one of the devices according to the Ausfühmngsbeispiele described below.

2. Subsequently, the base device is applied to the product packaging of the refrigerated goods of interest. The turnaround time at the beginning of thawing is determined.

3. If the determined turnaround time is longer than the predetermined target value, the following step 4 is performed; if the determined turnaround time is shorter than the predetermined target value, the following step 5 is performed; otherwise, there is no further need for adjustment, the process is terminated with step 8. 4. The current device (in the first, pass: base device) is reworked in a modified form so that the overall delay effect of all relevant layers of the device is reduced when transporting moisture. This is done by using one or more materials with better suitability for transporting moisture in at least one relevant layer, and / or the layer thickness of at least one relevant layer is reduced. The device thus obtained is tested according to the following step 6.

5. The current device (in the first pass: basic device) is reworked in modified form so that the overall delay effect of all relevant layers of the device is increased in the transport of moisture. This is done by using one or more materials with poorer suitability for transporting moisture in at least one relevant layer, and / or increasing the layer thickness of at least one relevant layer. The device thus obtained is tested according to the following step 6.

6. Subsequently, the modified device is applied to the product packaging of the refrigerated goods of interest. The turnaround time at the beginning of thawing is determined.

7. If the determined turnaround time is longer than the predetermined target value, the above step 4 is performed; if the determined turnaround time is shorter than the predetermined target value, the above step 5 is performed; otherwise, the process is ended with step 8.

8. The last device tested meets the specification; There is no further need for modification.

According to a preferred embodiment, the retarding effect of one or more layers is adjusted by using polyethyleneglycol as a matrix material (eg in the indicator layer, release layer and / or activator layer). In this case, in particular by changing the chain length (ie molar mass) of the polyethylene glycol and / or the mixing ratio of PEG molecules of different molecular weights, the retardation effect can be set as desired. Suitable molar masses are in the range from 600 to 4000 g / mol, preferably in the range from 800 to 1500 g / mol. When using mixtures, liquid polyethylene glycols having a molecular weight of less than 600 g / mol can also be used. Similarly, by adjusting the molecular weight of other polymeric matrix constituents such as polyvinyl alcohol, the retarding effect can be adjusted.

5.13. manufacturing

The device according to the invention can be produced by all methods in which the respective layers are formed or provided and can be brought into contact with the respectively adjacent layers. In this case, neither the sequence of the individual process steps (provision or formation of the respective layer, as well as contacting with the neighbor or the adjacent), nor the techniques used for the formation of layers. However, the following procedures have proved to be advantageous.

Version 1);

(Ä- 1) providing the cover layer (a),

(A-2) coating the cover layer (a) with the indicator layer (b),

(A-3) if necessary drying the indicator layer (b),

for making an assembly (A)

(B-1) providing a retardation layer (d),

(B-2) coating the retardation layer (d) with the activator layer (c),

(B-3) if necessary, drying of the activator layer (c)

for making an assembly (B);

(C) laminating the assemblies (A) and (B).

The timing of execution of steps (A-1) to (A-3) in relation to steps (B-1) to (B-3) is not specified.

Optional additional layers such as release or adhesive layers are introduced at a suitable location by performing the following additional steps:

(X-1) coating the already formed or provided adjacent layer with the suitable material to form the additional layer to be applied; (X-2), if necessary, drying of the additionally applied layer.

For example, if a further adhesive layer is to be introduced between the cover layer and the indicator layer, the above-mentioned steps (X-1) and (X-2) between the steps

(A-1) and (A-2). In contrast, if an adhesive layer under the retardation layer (d), the relevant steps (XI) and (X-2) may be carried out before step (BI) or at any later date.

Variant (II):

Hereby, all layers are applied sequentially (i.e., after providing or applying and drying the respective preceding layer). In order to avoid a premature color reaction at the boundary between indicator layer and activator layer, a separation layer between these two layers is provided in this variant.

The order of application of the individual layers is determined by the desired order of the layers in the device to be manufactured. However, it is possible to reverse the order of application of the individual layers, i. it may be provided as a first step, the cover layer (a) or the retardation layer (d). Thus, the following procedures for an exemplary encryption order result:

(D-1) providing the cover layer (a),

(D-2) coating the cover layer (a) with the indicator layer (b),

(D-3) if necessary drying the indicator layer (b),

(D-4) coating the indicator layer (b) with the liner layer (t),

(D-5) if necessary, drying of the separating layer (t)

(D-6) coating the separation layer (t) with the activator layer (c),

(D-7) if necessary drying of the activator layer (c)

(D-8) coating the activator layer (c) with the retardation layer (d),

(D-9) optionally drying the retardation layer (d); such as

(D'-l) providing the retardation layer (d).

D ^' -2) coating the retardation layer (d) with the activator layer (c),

(D-3) optionally drying the activator layer (c),

(D'-4) coating the activator layer (c) with the release layer (t),

(D ^' -5) if necessary drying of the trimer layer (t)

(D ^* -6) coating the separation layer (t) with the indicator layer (b),

(D'-7) if necessary drying the indicator layer (b)

(D '-8) coating the indicator layer (b) with the cover layer (a),

(D'-9) if necessary, drying of the cover layer (a) In these process variants, any additional layers present, such as further release or adhesive layers, can be introduced at a suitable point by carrying out the additional steps (XI) and (X-2) described above.

In alternative layer sequences according to Figures 1 to 13, the order of the order of the individual layers changes accordingly. Of course, layers can be omitted in these processes. According to a preferred variant of the methods described above, no release layer is applied. So steps D-4 and D5 or D'4 and D'5 are gone. In this case, it is essential to avoid premature color creation between activator and indicator during production. This can be achieved by using a volatile solvent in the printing process. Particularly suitable volatile solvents are, in particular, organic solvents which have a vapor pressure which is higher than the vapor pressure of water (in each case at 20 ° C.) and / or in which the boiling point is lower than in the case of water. They include ethanol, acetone, diethyl ether, methanol, isopropanol, ethyl acetate and methyl acetate, and mixtures of such solvents. Preferred is ethanol. Printing is done layer by layer as above. It is very advantageous that the layer printed as the second printed color formation layer is dried as quickly as possible immediately after application. In the above methods, this means that steps D6 and D7 are performed almost simultaneously and directly after step D-3 (or that steps D'-6 and D'-7 are performed almost simultaneously and directly after step D'-3 become). Immediate drying can be achieved by creating a gas stream, preferably an air stream, over the printed surface. The volatile solvent is removed by the gas stream before it comes to an unwanted Wanderang the activator in the indicator layer.

The application of the layers can be done by any technology suitable for forming thin layers. Particularly suitable printing presses have been found that are able to apply several layers of material in succession and each to dry directly after the order. For example, printing presses that work according to the offset, flexographic or screen printing methods are suitable. Other methods of applying thin layers include spraying, doctoring, dipping, etc.

The compositions to be applied for each layer of material are selected in view of their viscosity to the requirements of the. (Pressure) method adapted. For this purpose, suitable thickening agents can be used. Suitable are all thickeners that are inert to the indicator and activator, and do not hinder the desired transport of activator to indicator. As examples are polysaccharides such as pectin, xanthan, guar gum, agar-agar, cellulose and cellulose To name derivatives as well as calcium acetate and glycerin. The desired viscosity can also be achieved by suitably adjusting the concentration of the materials in the chosen solvent. If a further increase in the concentration is desired, the preparation of the solution can also be carried out at elevated temperature. Thus, for example, it is possible to obtain a highly concentrated solution of citric acid in water by preparing a saturated solution at ea. 50 ° C to 60 ° C. In this embodiment, the application of the materials can also be carried out at elevated temperature to prevent premature solidification or crystallization of individual components.

On the other hand, when using spraying it is not necessary to increase the viscosity of the solution to be sprayed on e.g. increase by adding thickening agents.

The drying of the individual layers applied (as well as the dry storage of the device produced) are important to prevent premature color change. The degree of drying must be selected to meet this requirement. As already mentioned in Sections 5.6 and 5.9, it may be advantageous to accelerate drying to form one or more of the layers of the device according to the invention by applying a plurality of thin layers of the same composition, wherein the last layer applied before the application of the next layer is dried. As mentioned above, the drying can be accelerated by a gas flow, preferably air flow.

If desired, individual drying steps can still be abbreviated or completely avoided, as long as it is ensured that in the. Moment in which activator layer and indicator layer are brought into contact (possibly via an adhesive or release layer), the degree of drying is sufficiently high to prevent a color change. Of course, drying is not required if a (sufficiently dry) prefabricated film or layer is applied to the already existing layer (s).

In the embodiments of the present invention in which the inventive

Device is integrated into the packaging of the product to be cooled (eg by using the packaging material as a retardation layer), the preparation proceeds analogously, where expediently variant (II) is selected and the layer structure is based on the Verzögemngsschicht. Alternatively, the layer structure according to variant (II) could start from the cover layer and end before the delay layer, eg with formation of the activator layer. The intermediate thus produced can then be applied to the packaging. Another possibility is to proceed according to variant (I) and to produce arrangement (A) as described above. In the preparation of assembly (B), the activator layer and optionally further layers are applied directly to the package. Subsequently, arrangements (A) and (B) are laminated.

P.14, Applications

The inventive device is suitable for monitoring the thermal history of any products that need to be permanently cooled. Here are primarily frozen food into consideration. Furthermore, the device according to the invention, however, is also suitable for use in connection with other products which must be permanently cooled or deep-frozen. However, the product to be cooled should contain moisture to ensure proper functioning of the device according to the invention.

The practical application is expediently carried out by applying the device according to the invention to the outer packaging of the product to be cooled. Thus, an easy recognizability of the color change can be ensured. It is of course important to ensure that moisture from the inside of the package can get to the device according to the invention, as soon as the cold chain is interrupted.

A significant advantage of the present invention is that a reliable display takes place, regardless of whether there is a direct contact between refrigerated goods and display device. Therefore, the device according to the invention can be mounted anywhere on the package. The size of the area covered by the device according to the invention is not specified. In view of the easy recognizability of the color change, however, this area should advantageously not be less than 0.2 cm ² , preferably 0.5 cm ² , more preferably 0.8 cm ² .

The application of a logo, other labels or instructions is conceivable in connection with the applications of the present invention and also expedient to point the consumer to the invention. Logo, lettering, etc. can be done on the device according to the invention. However, it is important to ensure that the logo, lettering, etc. are attached so that the color change can be reliably detected. A complete top cover of the device according to the invention with e.g. a logo is to be avoided. Of course, it is within the scope of the present invention also possible to apply logo, lettering, etc. next to the device according to the invention on the packaging.

6. Preferred Aioföhriingsformen It is preferred that the present invention be characterized using the features, components, and / or measures exemplified above and as "preferred." More preferred are the embodiments of the present invention wherein two or more of the exemplified and / or or "preferred" characteristics, components and / or measures are combined.

Particularly preferred are;

(i) the use of the cover layer materials exemplified and / or referred to as "preferred" in devices having a layer order as shown in Figures 1-13;

(ii) the use of the indicator layer materials exemplified and / or labeled as "preferred" in devices having a scanning sequence as shown in FIGS. 1-13;

(iii) the use of the exemplified and / or preferred materials for the activator layer in devices having a layer order as shown in Figs. 1-13;

(iv) the use of the delay layer materials exemplified and / or referred to as "preferred" in devices having a layer order as shown in FIGS. 1-13;

(v) the use of the exemplified and / or preferred materials for the subbing layers in devices having a layer order as shown in Figs. 1-13;

(vi) _"having the use of the exemplified and / or marked" preferred "as materials for the Tremischicht devices in a layer sequence according to Figures 1 to 13;

(vii) the use of the exemplified and / or "preferred" materials for the topcoat in combination with the use of the exemplified and / or "preferred" materials for the indicator layer;

(viii) the use of the exemplified and / or "preferred" materials for the topcoat in combination with the use of the exemplified and / or "preferred" materials for the activator layer;

(ix) the use of the exemplified and / or "preferred" materials for the topcoat in combination with the use of the exemplified and / or "preferred" materials for the retardant layer; the use of the materials mentioned as examples and / or as "preferred" for the cover layer in combination with the use of the materials mentioned for the exemplary purposes and / or as "preferred" for the adhesive layers;

the use of the materials mentioned as examples and / or as "preferred" for the cover layer in combination with the use of the materials exemplified and / or characterized as "preferred" for the release layer:

) the use of the exemplified and / or labeled as "preferred" materials for the indicator layer in combination with the use of exemplified and / or as "preferred" marked materials for the Aktivatorschichtm, but in addition it must be ensured that indicator and Activator (and the medium, for example, in terms of its pH) must be coordinated; *) the use of the indicator layer materials exemplified and / or labeled as "preferred" in combination with the use of the delay layer materials exemplified and / or characterized as "preferred";

) the use of the indicator layer materials exemplified and / or labeled as "preferred" in combination with the use of the adhesive layer materials exemplified and / or characterized as "preferred";

) the use of the indicator layer materials exemplified and / or labeled as "preferred" in combination with the use of the exemplified and / or "preferred" materials for the release liner;

■ ^" ) the use of the exemplified and / or" preferred "materials for the activator layer in combination with the use of the exemplified and / or as" preferred "materials for the retardation layer;

xvii) the use of the exemplified and / or "preferred" materials for the activator layer in combination with the use of the exemplified and / or "preferred" materials for the adhesive layers;

xviti) the use of the exemplified and / or as "preferred" marked materials for the activator layer in combination with the use of the exemplified and / or as "preferred" marked materials for the release layer; (xix) the use of the materials exemplified and / or referred to as "preferred" for the delay layer in combination with the use of the materials for the adhesive layers exemplified and / or characterized as "preferred";

(xx) the use of the exemplified and / or "preferred" materials for the retardation layer in combination with the use of the exemplified and / or "preferred" materials for the release layer; and

(xxi) the use of the materials mentioned as examples and / or as "preferred" for the adhesive layers in combination with the use of the materials exemplified and / or "preferred" materials for the release layer.

More preferred are those devices according to the invention in which the above-mentioned preferred combinations are further combined, ie devices with the feature combinations (i) - (ii), (i) - (iii), (i-iv), (i) - ( v), (i) - (vi), (i) - (vii), (i) - (viii), (i) - (ix), (i) -

(x), (i) - (xi), (i) - (xii), (i) - (xiii), (i) - (xiv), (i) - (xv), (i) - (xvi ), (i) - (xvii), (i) - (xviii). ₅ (i) - (xix), (i) -

(xx) _s (iMxxi), (ii) - (iii), (ii (iv), (ii) - (v), (ü (vi), (ii) - (vii), (ii) - (viii ), (ü) - (ix), (ii) - (x), (ii) ^» (xi),

(ii) - (xii), (ii) - (xiii), (ii) - (xiv), (ii) - (xv), (ii) - (xvi), (ii) - (xvii), (ii ) - (xviii), (ü) - (xix), (ii) - (xx), (ii) ~

(xxi) ₅ (iii) - (iv), (iii) - (v), (iii) - (vi), (iii) - (vii), (iii) - (viii) ₅ (iii) - (ix ), (iii) - (x.) _» (iii) - (xi), (iü) - (xii),

(iii) - (xiii), (iii) - (xiv), (iii) - (xv), (iii) - (xvi) ₅ (iii) - (xvti), (iii) - (xviii) ₅ (iii ) - (xix), (iii) - (xx), (iii) - (xxi), (iv) - (v), (iv) - (vi), (iv) - (vii), (iv) - (viii), (iv) - (ix), (iv) - (x), (iv) - (xi), (iv) - (xii), (iv) - (xiü),

(iv) - (xiv), (iv) - (xv), (iv) - (xvi), (iv) - (xvii), (iv) - (xviii), (iv) - (xix), (iv ) - (xx), (iv) - (xxi), (v) - (vi),

(v) - (vii), (v) - (viii), (v) - (ix), (v) - (x), (v) - (xi) _s (v) - (xii), (v ) - (xiii), (v) - (xiv), (v) - (xv), (v) - (xvi),

(v) - (xvii), (v) - (xvii), (v) - (xix), (v) - (xx), (v) - (xxi), (vi) - (vii), (vi ) - (viii), (vi) - (ix), (vi) - (x), (vi) -

(xi), (vi) - (xii) _s (vi) - (xiii), (vi) - (xiv), (vi) - (xv), (vi) - (xvi), (vi) - (xvii ), (vi) - (xviii), (vi) - (xix),

(vi) - (xx), (vi) - (xxi) _? (vii) - (viii), (vii) - (ix), (vii) - (x) _» (vii) - (xi), (vii) - (xii), (vii) - (xiii), (vii ) - (xiv) _s

(vii) - (xv), (vii) - (xvi), (vii) - (xvii), (vii) - (xvii), (vii) - (xix), (vii) - (xx). (vii) - (xxi), (viii) - (ix),

(viii) - (x), (viii) - (xi), (viii) - (xii), (viii) - (xiii), (viii) - (xiv), (viii) - (xv), (viii ) - (xvi), (viii) - (xvii), (vüi) - (xvüi), (viii) - (xix), (viii) - (xx) _s (viii) - (xxi), (ix) - (x), (ix) - (xi), (ix) - (xii), (ix) - (xi), (ix) - (xiv), (ix) - (xv), (ix) - (xvi ), (ix) - (xvii) ₅ (ix) - (xviii), (ix) - (xix), (ix) - (xx), (ix) - (xxi), (x) - (xi), (x) - (xü), (x) - (xiü), (x) - (xiv), (x) - (xv), (x) - (xvi), (x) - (xvii) ₅ (x (xviii), (x) - (xix), (x) - (xx), (x) - (xxi),. (xi) - (xii), (xi) - (xiii), (xi) - ( xiv), (xi) - (xv), (xi) - (xvi), (xi) - (xvii), (xi) - (xvüi), (xi (xix), (xi) -

(xx), (xi) - (xxi), (xii) - (xiii), (xii) - (xiv, (xii) - (xv). (χπ) - (χνι), (xii) - (xvii) , (xii) - (xviii), (xii) - (xix), (xii) - (xx), (xii) - (xxi) ₅ (xiii) - (xiv), (xiii) - (xv), ( xiii) - (xvi), (xiü) - (xvii), (xiii) - (xviii), (xüi) - (xix), (xiii) - (xx), (xiii) - (xxi), (xiv) - (xv), (xiv) - (xvi), (xiv) - (xvii), (xiv) - (xviii), (xiv) - (xix), (xiv) - (xx), (xiv) - ( xxi) ₄ (xv) - (xvi), (xv) - (xvii), (xv) - (xviii), (xv) - (xix), (χν) - (χ ^χ ), (xv) -

(xxi), (xvi) - (xvu), (xvi) - (xviii), (xvi) - (xix), (xvi) - (xx), (xvi) - (xxi), (xvii) - (xviii ), (xvii) - (xix), (xvii) - (xx), (xvii) - (xxi), (xviii) - (xix), (xviii) - (xx), (xviii) - (xxi), (xix) - (xx), (xix) - (xxi) and (Xx) - (xxi). Even more preferred are combinations of those listed above

Combinations.

With regard to the preparation processes according to the invention, preference is given in particular to the processes mentioned in Section 5.13 above, which lead to the preferred devices according to the invention. Preference is also given to processes using printing machines, especially if they lead to the preferred devices according to the invention.

For example, in view of industrial production of the devices according to the invention, the following embodiments are particularly preferred;

A preferred variant has the following layer sequence;

Cover layer - if necessary adhesive layer - indicator layer - activator layer.

These layers are possibly on the adhesive layer on serving as Verzögemngsschicht

Product packaging applied (with the adhesive layer preferably laterally of the indicator and activator), A similar layer sequence is shown in Figure 5a, but additionally with a release layer. According to the preferred variant described here, the separating layer is avoided by suitable production methods. Such suitable preparation may be accomplished using an industrial printing process (e.g., flexographic printing). In this case, the cover layer is first printed with the indicator layer, followed by further printing with the activator layer. In order to avoid premature color change, suitable measures must be taken in this case so that the activator layer dries so quickly immediately after application that no significant migration takes place in the activator layer. As described above, this can be done by using a volatile solvent. The device thus obtained can, e.g. on silicone paper, to be stored. It is adhered to the product packaging in a (possibly spatially and / or temporally) separate process step. In this case, an anthocyanidin dye is preferably used as indicator and citric acid, lactic or tartaric acid as activator. Very particular preference is given to the abovementioned embodiment when using a cyanidin dye as indicator in conjunction with citric acid as activator.

Another preferred variant has the following layer sequence:

Cover layer - if necessary adhesive layer - indicator layer - release layer - activator layer. These layers are optionally applied over the adhesive layer on the product packaging serving as a delay layer (with the adhesive layer preferably laterally of the indicator and activator layer). Such a layer sequence is shown in FIG. 5a. In this variant, it is particularly preferred to print a paper serving as a release layer on one side with indicator layer and on the other side with activator layer. The resulting intermediate product can be punched out in the appropriate format and adhered to a cover layer provided with an adhesive layer. The device obtained in this way can be stored, for example on silicon paper. It is adhered to the product packaging in a (possibly spatially and / or temporally) separate process step. Here, too, an anthocyanidin dye is preferably used as indicator and citric acid, lactic or tartaric acid as activator. Very particularly preferred is the abovementioned embodiment when using a cyanidin dye as an indicator in conjunction with citric acid as activator.

The preferred uses and applications of the present invention are, in particular, the uses and applications mentioned in Section 5.14 above, which involve the use of the preferred devices of the invention,

7. Examples Example 1

A device according to the invention is produced according to production variant I using a flexographic method. The layer structure corresponds to the layer sequence shown in FIG. 9c.

The cover layer is off. UPM Rafiatac® PP Ciear TC50 P. This PP film is already provided with an adhesive layer ex works and the UPM Rafiatac® acrylate-based adhesion layer "SP38" is therefore also available.

The activator layer is formed on the citric acid adhesive in a cellulosic matrix. The application rate is 6 g / m. The layer is in the printing process in the form of an aqueous dispersion with a. Content of cellulose of about 5 wt.% And a content of citric acid of about 1 wt.% Applied and then dried directly.

Cyanidin is used as an indicator in a cellulose matrix. The indicator layer is applied to tissue paper of a thickness of 25 g / m ² as a retardation layer. The application rate is 6 g / m ² . Also in this case, the layer is in the form of an aqueous Dispersion in which the content of cellulose at 5 wt.% And the content of cyanidin is 1 wt.%. The layer is dried immediately after application.

Subsequently, activator layer and indicator layer are laminated on each other,

A color change can be seen between the first thawing of the chilled product (30 ° frozen peas temperature increase from -1 8 ° C to 20 ° C) after 150 minutes.

Example 2

A device according to the invention is produced analogously to Example 1, with the difference that newsprint of a thickness of 50 g / m ^{2 is} used.

In this example, a color change was observed after 200 minutes under identical test conditions.

Claims

8. Patent Claims

1. Device for displaying the history of a product, comprising the following layers:

(a) a moisture-impermeable cover layer (1),

(b) an indicator layer (2) which comprises at least one indicator,

(c) an activator layer (3), which comprises at least one activator, and

(d) an optional delay layer (4), wherein the cover layer is arranged above the indicator layer, the activator layer and the delay layer, the indicator layer being arranged between the cover layer and the optional delay layer, and wherein the activator layer can be absent if an indicator is used which activated by H2O.

2. Device according to claim 1, wherein the indicator layer comprises a pH indicator, preferably an anthocyanin dye, and the activator layer has an acid or base as an activator.

3. Device according to one or both of claims 1-2, wherein the indicator and / or activator layer comprises a matrix material which is selected from at least one of agar agar, carrageenan, gelatin, starch, gum arabic, cellulose, arrowroot starch, guar gum and Polyethylene glycol.

4. Device according to one or more of claims 1 to 3, wherein the indicator layer and / or the activator layer contains at least one hygroscopic salt, which is preferably selected from the group consisting of magnesium chloride, potassium chloride and calcium chloride.

5. Device according to at least one of claims 1 to 4, wherein the retardation layer (d) is present and is made of paper or cardboard with a thickness of 40-60 g/cm ² in accordance with DIN 6730.

6, device according to at least one of claims 1-5, wherein the activator layer

(d) is formed from 2-30, preferably 3-8, more preferably 4-6 sequential individual layers.

7. Device according to at least one of claims 1-6, wherein the indicator layer (c) is formed from 2-40, preferably 4-10, more preferably 6-8 sequential Emzel layers.

8. Device according to at least one of claims 1-7, wherein

the layers (a), (b), (c) and (d) as follows:

(a) cover layer (1),

(b) indicator power (2),

(d) optional delay layer (4), and

(c) activator layer (3), or

(a) cover layer (1),

(c) activator layer (3),

(b) indicator power (2), and

(d) optional delay layer (4), or

(a) cover layer (1),

(b) indicator power (2),

(c) activator layer (3), and

(d) optional delay layer (4) are arranged.

9. Device according to at least one of claims 1 -8, which is applied to product packaging,

10. Device according to claim 9, which has a time period between the first thawing of the refrigerated goods and the color change in the range of 0.5 h to 3 h

11. A method for producing a device according to at least one of claims 1 -10; wherein one or more of the layers present in the device by carrying out steps (i) and (ii) one or more times sequentially:

(i) Printing and

(ii) drying the printed layer is formed.

12. Method for producing a device according to at least one of claims 1 to 10, which is selected from the following methods:

(a) Method comprising the following steps:

(A-1) Providing the cover layer (1),

(A-2) coating the cover layer (1) with the indicator layer (2),

(A-3) drying the indicator layer (2),

to produce an arrangement (A)

(B-l) providing a delay layer (4),

(B-2) coating the delay layer (4) with the activator layer (3),

(B-3) Drying the activator layer (3)

to produce an arrangement (B);

(C) Concealing the arrangements (Ä) and (B) and

(b) Procedure comprising the following steps:

(A'-l) providing the cover layer (1),

(A'-2) coating the cover layer (a) with the activator layer (3),

(A'-3) drying the activator layer (3),

to produce an arrangement (Α')

(Β'-Γ) providing a retarding layer (d),

(B'-2) coating the retardation layer (d) with the indicator layer (2),

(B'-3) Drying the indicator layer (2)

to produce an arrangement (B ⁶ );

(C) Concealing the arrangements (Α') and (Β').

13. A method for producing a device according to at least one of claims 1 to 10, in which a first layer, selected from the top layer and the retardation layer, is prepared; and in which the others. Layers of the device are deposited sequentially according to the order in which they are arranged in the device; wherein at least when applying the indicator layer and activator layer, the layer to be applied earlier is applied before the layer to be applied later. Layer is dried and the component or components of the layer to be applied later are provided and applied in a volatile organic solvent, provided that no further layer is provided between the indicator layer and the activator layer.

14. Packaging for frozen product, comprising the device according to one or more of the preceding claims 1 to 10.

15. Frozen product comprising the packaging according to claim 14.