DE102018132737A1 - Process and shrink tunnel for shrinking thermoplastic packaging material onto articles - Google Patents

Abstract

A shrink tunnel (100) for shrinking thermoplastic packaging material (22) onto article (2) is disclosed. The shrink tunnel (100) forms at least two heating zones (HZ1, HZ2) offset from one another in a direction of movement (BR) of the shrink tunnel (100) provided for the articles (2). It is further provided that the at least two heating zones (HZ1, HZ2) offset from one another in the direction of movement (BR) provided for the articles (2) for heating and shrinking the thermoplastic packaging material (22) onto articles (2) form different temperature levels, which differ Temperature levels are matched to established and / or known material characteristics of the thermoplastic packaging material (22).

Description

The present invention relates to a method and a shrink tunnel for shrinking thermoplastic packaging material onto articles.

Flat sheets of thermoplastic material are used, for example, as a film for shrinking processes in packaging technology. To produce the flat material web, the plastics are usually supplied as granules or in powder form, fed to an extruder and then discharged as a thermoplastic material via a slot die.

The respective thermoplastic sheet or the respective shrink film is provided as continuous material on rolls before being shrink-fitted, then arranged on several articles, subsequently passed together with the respective articles through a shrink tunnel and subjected to temperature there for shrinking. If the articles emerge from the shrink tunnel, a combination of articles is formed as a packaging unit, in which the individual articles are held together by means of the shrunk-on thermoplastic sheet or shrink film.

Such a device shows, for example DE 10 2010 032 455 A1 . The shrink tunnel, which is disclosed in the DE patent application, has a plurality of radiant heaters arranged along a transport route of the articles, which are jointly fixed to a support structure and can be raised and lowered together with the support structure for heating the articles. If the respective heat shrink film is subjected to temperature by the radiant heaters, it can expand by a small amount up to its crystalline melting point at the beginning in order to then shrink to a certain value.

In order to optimize the shrinking result, the individual radiant heaters can be specifically controlled according to the device of the DE patent application. The respective temperature control must take place depending on the material properties of the shrink film so that it can be shrunk onto the respective articles in a defined manner in order to hold the articles together. Such material webs made of thermoplastic or shrink films are made up of chain molecules, the cohesion of which is produced by means of intermolecular binding forces. Depending on the macromolecules, the forces are of different strengths and thus influence the thermal, mechanical and chemical behavior of the respective flat material web. A precise knowledge of the material characteristics of the respective thermoplastic sheet or the respective shrink film is therefore essential in order to be able to optimize a shrinking process.

If the material characteristics are not known or are insufficiently known, the articles held together via the respective shrink film after shrinking may have unstable storage. Likewise, a suboptimal choice of the respective shrinking material can be accompanied by tearing of the material and / or flowing of the material when shrinking.

In practice, thermoplastic films can also be provided with markings, such as product names, various graphics or the like. Shrinking processes are desirable in which, after the respective film has been shrunk onto the articles, a proportionality of the markings can at least be largely maintained. An over or under-proportional stretch, for example in the longitudinal direction, should at least be largely avoided in this case.

In order to improve the shrinking quality, it is provided in the prior art that the thermoplastic packaging material or the shrink film already applied to the article is first heated from below with a high amount of thermal energy when it enters the shrink tunnel. At a later time during the movement through the shrink tunnel, the thermoplastic packaging material is laterally heated with a high amount of thermal energy, whereas the warming decreases in the direction coming from below. It is true that the shrinking quality can often be improved as a result, but packs produced by means of such a shrinking tunnel often have an undesired wrinkle formation or a defect in edge and / or corner areas.

For this reason, an object of the invention can be seen in providing a possibility with which the shrinking quality can be further improved.

The above object is achieved by the subjects which comprise the features in the independent claims. Further advantageous embodiments are described by the subclaims.

The invention relates to a method for shrinking thermoplastic packaging material onto articles. It may be the case that a respective cut of thermoplastic packaging material is applied to several articles or to a respective combination of articles. From the respective cut of thermoplastic packaging material and the several Articles or from the respective cut of thermoplastic packaging material and the respective combination of articles can be produced by means of the method, if necessary, a container which comprises several articles and a respective cut of thermoplastic packaging material shrunk onto the several articles.

One step of the method provides for the movement of articles with the thermoplastic packaging material applied in each case through a shrink tunnel, the thermoplastic packaging material being shrunk onto the articles during the movement through the shrink tunnel. It may be the case that groupings are formed with several articles, to each of which a cut of thermoplastic packaging material is applied. The respective group of articles can then be moved through the shrink tunnel with the respective cut of thermoplastic packaging material, wherein the respective cut of thermoplastic packaging material is shrunk onto the respective group.

It is envisaged that at least two different temperatures or at least two different temperature levels act on the thermoplastic packaging material during the movement through the shrink tunnel, which at least two different temperature levels or which at least two different temperatures are known and / or known Material characteristics of the thermoplastic packaging material are matched. The at least two different temperature levels can be provided by a respective shrinking medium designed as a gaseous volume flow. It may thus be the case that the thermoplastic packaging material is acted upon by a first shrink medium which is in the form of a gaseous volume flow and which has a first temperature level. It may also be the case that the thermoplastic packaging material has a shrinking medium in the form of a gaseous volume flow, the second temperature level of which is larger than the first temperature level of the first shrinking medium in the form of a gaseous volume flow. The first temperature level and the second temperature level can be matched to the determined and / or known material characteristics of the thermoplastic packaging material.

In particular, it may be that the thermoplastic packaging material is first heated to a first temperature level during the movement through the shrink tunnel, the thermoplastic packaging material temporally forming a temperature during the entire heating at the first temperature level, which temperature was found to be below a material characteristic of the thermoplastic packaging material and / or known temperature at which the thermoplastic packaging material changes to the thermoplastic aggregate state. The first temperature level can also be provided via a shrink medium, which is designed as a gaseous volume flow. As an alternative or in addition to this, it may be that the first temperature level is provided via at least one electrically operated heating device which may be designed as part of the shrink tunnel.

It can further be provided that the thermoplastic packaging material is heated at a second temperature level following this and during the further movement through the shrink tunnel, the thermoplastic packaging material forming a temperature during the heating at the second temperature level, which temperature is within a material characteristic of the thermoplastic packaging material and / or known temperature range at which the thermoplastic packaging material changes to the thermoplastic aggregate state. The second temperature level can thus be formed by a temperature level which is characterized by a shrinking temperature effective for the thermoplastic packaging material. The second temperature level can also be provided via a shrink medium, which is designed as a gaseous volume flow or as a second gaseous volume flow.

Furthermore, during the movement through the shrink tunnel, the thermoplastic packaging material may be acted on with at least two types of exposure to shrink medium which differ in terms of the amount and / or direction, which at least two in terms of amount and / or the direction of different types of exposure to shrink medium are matched to the established and / or known material characteristics of the thermoplastic packaging material. The shrink medium can be designed as a hot gas volume flow or as a gaseous volume flow. It may be the case that a first direction provides for the respective shrink medium or the gaseous volume flow to be applied to the thermoplastic packaging material in the direction coming from below. Furthermore, it can be the case that a second direction provides for lateral or oblique loading of the thermoplastic packaging material. In A region of the shrink tunnel, in which heating of the thermoplastic packaging material is provided with the first temperature level, it may be that the coming from below towards another region of the shrink tunnel, in which heating of the thermoplastic packaging material with the second temperature level is provided is enlarged.

A respective time period with which the thermoplastic packaging material is acted on at different times during the movement through the shrink tunnel with the respective temperature level can be matched to established and / or known material characteristics of the thermoplastic packaging material. In particular, it may be the case that a conveying speed of at least one horizontal conveyor device moving the articles together with the applied thermoplastic packaging material through the shrink tunnel is controlled and / or regulated in a defined manner to the established and / or known material characteristics of the thermoplastic packaging material.

It may be the case that the material characteristics of the thermoplastic packaging material are determined by analyzing a sample of the thermoplastic packaging material before the movement of articles with the thermoplastic packaging material applied in each case through the shrink tunnel.

• - ein Temperaturniveau bzw. ein definierter Temperaturbereich, welcher als wirksamer Schrumpfungsbereich des thermoplastischen Verpackungsmaterials ausgebildet ist bzw. ein Temperaturbereich bzw. ein definierter Temperaturbereich, bei welchem das thermoplastische Verpackungsmaterials den thermoplastischen Aggregatszustand ausgebildet;
• - eine temperaturabhängige Schrumpfrate des thermoplastischen Verpackungsmaterials über den Zeitverlauf in einer für die Bewegung der Artikel durch den Schrumpftunnel vorgesehenen Bewegungsrichtung;
• - eine temperaturabhängige Schrumpfrate des thermoplastischen Verpackungsmaterials über den Zeitverlauf schräg zu einer für die Bewegung der Artikel durch den Schrumpftunnel vorgesehenen Bewegungsrichtung;
• - eine Oberflächenspannung des thermoplastischen Verpackungsmaterials;
• - ein Reibwert des thermoplastischen Verpackungsmaterials;
• - Ein Verhalten des thermoplastischen Verpackungsmaterials bei stoffschlüssiger Verbindung mit weiterem thermoplastischem Verpackungsmaterial;
• - Informationen zur Reißdehnung bzw. Bruchdehnung, zum E-Modul und/oder zur Zugfestigkeit des thermoplastischen Verpackungsmaterials;
• - Informationen zur Stärke des thermoplastischen Verpackungsmaterials.

It may be the case that the material characteristics determined during the analysis of the sample of the thermoplastic packaging material, to which the at least two different temperature levels are matched, include one or more of the following material characteristics:

• a temperature level or a defined temperature range, which is designed as an effective shrinkage range of the thermoplastic packaging material, or a temperature range or a defined temperature range, at which the thermoplastic packaging material forms the thermoplastic aggregate state;
• a temperature-dependent shrinkage rate of the thermoplastic packaging material over time in a movement direction provided for the movement of the articles through the shrink tunnel;
• a temperature-dependent shrinkage rate of the thermoplastic packaging material over the course of time obliquely to a movement direction provided for the movement of the articles through the shrink tunnel;
• - a surface tension of the thermoplastic packaging material;
• - a coefficient of friction of the thermoplastic packaging material;
• - A behavior of the thermoplastic packaging material in the case of a material connection with further thermoplastic packaging material;
• - Information on the elongation at break or elongation at break, the modulus of elasticity and / or the tensile strength of the thermoplastic packaging material;
• - Information on the thickness of the thermoplastic packaging material.

The shrink rate can be designed as a shrink force or as a contraction force or as a heat shrink force and cold shrink force.

Embodiments have proven themselves in which a temperature-dependent shrinkage rate of the thermoplastic packaging material over the course of time in a movement direction provided for the movement of the articles as well as the material characteristics determined during the analysis of the sample of the thermoplastic packaging material, to which the at least two different temperature levels are coordinated a temperature-dependent shrink rate of the thermoplastic packaging material is inclined or orthogonal to a movement direction provided for the movement of the articles through the shrink tunnel. The temperature-dependent shrinkage rate of the thermoplastic packaging material obliquely or orthogonally to the direction of movement intended for the movement of the articles through the shrink tunnel and the temperature-dependent shrinkage rate of the thermoplastic packaging material in the movement direction provided for the movement of the articles through the shrink tunnel can, if necessary, as individual or separate material characteristics it is determined to which individual or separate material characteristics the at least two different temperature levels are matched.

It is also conceivable that after determining the material characteristics of the thermoplastic packaging material by analyzing the sample of the thermoplastic packaging material, the shrink tunnel is automatically or automatically controlled to act on the thermoplastic packaging material with the at least two different temperature levels, which at least two different temperature levels on the determined Material characteristics of the thermoplastic packaging material are matched.

The invention also relates to a shrink tunnel for shrinking thermoplastic packaging material onto articles. Features which have already been described above for various embodiments of the method can also be provided in the embodiments of the shrink tunnel and the packaging system described below and are not mentioned several times. Features described below, which relate to the shrink tunnel or the packaging system, may also be provided in the previously described embodiments of the method. The shrink tunnel and / or the packaging system can be designed to carry out the method described above.

The shrink tunnel forms at least two heating zones offset from one another in a direction of movement of the shrink tunnel provided for the articles. The at least two heating zones offset from one another in a direction of movement of the shrink tunnel intended for the articles can, if appropriate, connect directly to one another or follow one another directly.

In the shrink tunnel, it is also provided that the at least two heating zones offset from one another in the direction of movement provided for the articles for heating and shrinking the thermoplastic packaging material onto articles form different temperature levels, which different temperature levels are matched to established and / or known material characteristics of the thermoplastic packaging material.

It may be that the different temperature levels of the at least two heating zones offset from one another in the direction of movement provided for the articles are matched to established and / or known material characteristics of the thermoplastic packaging material in such a way that the thermoplastic packaging material forms a temperature when it leaves a first heating zone is below a temperature range established and / or known as the material characteristic of the thermoplastic packaging material, at which the thermoplastic packaging material changes to the thermoplastic aggregate state. It may be the case that the thermoplastic packaging material forms a temperature when leaving the first heating zone, which temperature is increased or increased compared to a temperature which the thermoplastic packaging material forms when entering the shrink tunnel. The thermoplastic packaging material may thus be preheated during the movement through the first heating zone, the shrinking of the thermoplastic packaging material onto the articles taking place in the region of a second heating zone.

It may also be the case that the thermoplastic packaging material forms a temperature in a second heating zone, which preferably adjoins the first heating zone in the direction of movement intended for the articles, which temperature is within a temperature range established and / or known as the material characteristic of the thermoplastic packaging material is located, in which the thermoplastic packaging material forms the thermoplastic aggregate state.

Furthermore, the at least two heating zones offset from one another in the direction of movement provided for the articles can each have a plurality of nozzles, through which the thermoplastic packaging material can be acted upon with shrink medium, which respective shrink medium forms the respective temperature level of the respective heating zone. It can be provided here that the nozzles of the at least two different heating zones can be controlled differently with regard to the amount and / or the direction of the shrink medium to be dispensed in each case and can be controlled in each case in accordance with the known and / or established material characteristics of the thermoplastic packaging material.

It is conceivable that the shrink tunnel comprises at least one horizontal conveyor device, via which the articles with their applied thermoplastic packaging material can be transported through the at least two heating zones offset from one another in the direction of movement provided for the articles. The at least one horizontal conveyor device can be controlled by the at least two heating zones at a transport speed that is matched to the known and / or established material characteristics for moving the articles with the applied thermoplastic packaging material. To control the at least one horizontal conveyor device with the transport speed matched to the known and / or determined material characteristics, a control and / or regulating device can be provided which is connected to the at least one horizontal conveyor device.

It may be that the at least one horizontal conveyor device comprises a first horizontal conveyor device which is used to move articles with applied thermoplastic packaging material through a first heating zone is provided and that the at least one horizontal conveyor device comprises a second horizontal conveyor device which is provided for the subsequent movement of articles with applied thermoplastic packaging material through a second heating zone. It is conceivable here that a conveying speed of the first horizontal conveying device and the second horizontal conveying device are designed differently and in each case matched to the determined and / or known material characteristics of the thermoplastic packaging material.

The invention also relates to a packaging system for articles. The packaging system includes a shrink tunnel according to an embodiment of the preceding description. The packaging system further comprises a device for determining material characteristics on thermoplastic packaging material to be shrunk on articles. The packaging system provides that the shrink tunnel and the device are operatively connected to one another in such a way that the shrink tunnel can match the different temperature levels of the at least two heating zones offset from one another in the direction of movement provided for the articles to the material characteristics of the thermoplastic packaging material determined via the device.

It may be that the shrink tunnel and the device are operatively connected to one another in such a way that the shrink tunnel can automatically match the different temperature levels of the at least two heating zones offset from one another in the direction of movement provided for the articles to the material characteristics of the thermoplastic packaging material determined via the device.

• - eine temperaturabhängige Schrumpfrate des thermoplastischen Verpackungsmaterials über den Zeitverlauf in einer für die Bewegung der Artikel durch den Schrumpftunnel vorgesehenen Bewegungsrichtung;
• - eine temperaturabhängige Schrumpfrate des thermoplastischen Verpackungsmaterials über den Zeitverlauf schräg zu einer für die Bewegung der Artikel durch den Schrumpftunnel vorgesehenen Bewegungsrichtung;
• - eine Oberflächenspannung des thermoplastischen Verpackungsmaterials;
• - einen Reibwert des thermoplastischen Verpackungsmaterials;
• - ein Verhalten des thermoplastischen Verpackungsmaterials bei stoffschlüssiger Verbindung mit weiterem thermoplastischem Verpackungsmaterial;
• - Informationen zur Reißdehnung, zum E-Modul und/oder zur Zugfestigkeit des thermoplastischen Verpackungsmaterials;
• - Informationen zur Stärke des thermoplastischen Verpackungsmaterials.

Embodiments have proven successful in which the device for determining material characteristics can determine one or more of the following material characteristics:

• a temperature-dependent shrinkage rate of the thermoplastic packaging material over time in a movement direction provided for the movement of the articles through the shrink tunnel;
• a temperature-dependent shrinkage rate of the thermoplastic packaging material over the course of time obliquely to a movement direction provided for the movement of the articles through the shrink tunnel;
• - a surface tension of the thermoplastic packaging material;
• - a coefficient of friction of the thermoplastic packaging material;
• a behavior of the thermoplastic packaging material in the case of a material connection with further thermoplastic packaging material;
• - Information on the elongation at break, the modulus of elasticity and / or the tensile strength of the thermoplastic packaging material;
• - Information on the thickness of the thermoplastic packaging material.

The shrink rate can be designed as a shrink force or as a contraction force or as a heat shrink force and cold shrink force.

In particular, it may be that the device for determining material characteristics can determine a temperature-dependent shrinkage rate of the thermoplastic packaging material over time in a movement direction provided for the movement of the articles through the shrink tunnel as a first material characteristic. Furthermore, it can be the case that the device for determining material characteristics can determine a temperature-dependent shrink rate of the thermoplastic packaging material over the course of time obliquely to a movement direction provided for the movement of the articles through the shrink tunnel as an additional second material characteristic. The shrink tunnel or the packaging system can be designed in such a way that the at least two heating zones offset from one another in the direction of movement provided for the articles for heating and shrinking the thermoplastic packaging material on articles form different temperature levels, which different temperature levels on the determined first material characteristic and also on the determined additional second material characteristic of the thermoplastic packaging material are coordinated.

In particular, a longitudinal and / or transverse shrinkage of the thermoplastic packaging material can be determined in various embodiments when the material characteristics are determined.

It may be that a sample of a defined dimension of the thermoplastic packaging material in the context of the analysis of a heating above a shrinkage temperature effective for the respective material of the sample or above a temperature effective for the respective material of the sample, at which the sample changes into the thermoplastic aggregate state , is subjected. The sample piece already mentioned above can, for example be cuboid or square in shape and have a dimensioning which allows a dimensional change, which will be described in more detail below and results from heating, to be easily recognized. It is clear to the person skilled in the art that he can use numerous suitable geometries for the respective dimension of the specimen, so that the invention is not restricted to cuboid or square specimens.

For example, it is conceivable that to determine the material characteristics of the thermoplastic packaging material, the respective sample piece is heated by exposure to a gaseous medium, such as hot air or the like. In preferred embodiments, however, it may be that in order to determine the material characteristics of the thermoplastic packaging material, the respective sample piece is heated by an active connection with a heating plate and lies flat on the heating plate - if necessary with a carrier substrate arranged between the heating plate and the respective sample piece. Advantageously, when the sample is heated by a heating plate, the entire sample can be at least largely uniformly heated. The heating plate can be designed as a component of the device already described above for determining material characteristics of the thermoplastic packaging material.

It is conceivable, for example, that the heating plate is at least approximately at ambient temperature, that the sample piece is arranged on the heating plate or on the possibly interposed carrier substrate, and that the heating plate is subsequently put into operation with increasing heating of the sample piece. As a result of the progressive heating of the sample piece, it can be observed when the sample piece changes into the thermoplastic aggregate state. The temperature level or the respective temperature at which the specimen changes to the thermoplastic aggregate state can be recorded or determined as a material characteristic. In further embodiments it is also conceivable that the heating plate is preheated up to a certain temperature or a certain temperature level and then the respective sample piece is arranged on the heating plate - or possibly on the carrier substrate interposed between the heating plate and the sample piece.

In preferred embodiments, the sample piece is arranged in a receptacle. The receptacle can be brought into contact with the heating plate in order to heat the sample. Furthermore, the carrier substrate, on which the sample piece may be placed, can be arranged in the receptacle when heated and when the respective dimensional change is detected. The definition “recording” can thus be understood as a physical part of the device for determining material characteristics of the thermoplastic packaging material. In other embodiments, the term “recording” can also be defined as a region within which the respective sample piece is arranged when heated.

The heating plate can be designed such that it is heated up to a certain temperature or a certain temperature level and then maintains the certain temperature or the certain temperature level. For example, the temperature can be set at 130 ° C or 150 ° C. The person skilled in the art can select the appropriate temperature taking into account the intended later shrinkage process in which the respective thermoplastic material is shrunk onto articles.

Furthermore, after heating over the course of time, a dimensional change of the specimen can be observed and / or measured in the progressive shrinking process. The observation of the progressive shrinkage can begin at a certain point in time after heating the specimen and end at a certain point in time or after a certain duration. For example, provision can be made for the observation and / or measurement of the dimensional change in the sample to be started immediately after reaching a shrinkage temperature effective for the respective material or immediately after reaching a temperature at which the sample changes to the thermoplastic aggregate state. Such embodiments have proven particularly useful since the dimensional change begins immediately after the shrinking temperature effective for the respective material has been reached or immediately after a change to the thermoplastic aggregate state, and thus the entire dimensional change of the respective sample piece can be detected over the course of time.

If the sample has reached a predetermined temperature, a temperature control device, which will be described in more detail below, can be controlled within the scope of various embodiments such that the temperature of the sample is at least largely maintained during the observation and / or during the measurement of the dimensional change.

In further embodiments, the temperature level of the specimen can be varied over the course of time and while observing and / or measuring the dimensional change. Various temperature values can preferably be specified here, at which the sample piece is tempered over the course of time and during the detection and / or observation of the dimensional change. From the detected and / or observed dimensional change, it may be possible to infer a material characteristic or a first material characteristic, which is designed as a temperature-dependent shrink rate of the thermoplastic packaging material over time in a movement direction provided for the movement of the articles through the shrink tunnel. This material characteristic or this first material characteristic can possibly be designed as information about a longitudinal shrinkage of the thermoplastic packaging material. As an alternative or in addition to this, it can be concluded from the detected and / or observed dimensional change that a material characteristic or an additional second material characteristic is obtained, which as the temperature-dependent shrinkage rate of the thermoplastic packaging material obliquely to a movement direction provided for the movement of the articles through the shrink tunnel is trained. This material characteristic or this additional second material characteristic can possibly be designed as information about a transverse shrinkage of the thermoplastic packaging material. It may be the case that the thermoplastic packaging material is acted on at different times during the movement through the shrink tunnel with at least two different temperature levels, which at least two different temperature levels are matched to the determined first material characteristic and also to the additionally determined second material characteristic.

Furthermore, it may be that in the course of the analysis of the sample, at which the material characteristics are determined, a temperature with which the sample is applied is varied over the course of time. In this way, precise statements can be made as to how the respective thermoplastic material behaves when the temperature changes over time.

In addition, the analysis may establish a relationship between the observed and / or measured dimensional change of the sample, the duration of a shrinking process provided for the sample as part of the analysis, and the respective temperature and / or temperature change of the sample in the shrinking process, and derived from the context of material characteristics of the thermoplastic packaging material.

It may also be the case that the respective temperature and / or temperature change of the sample piece is continuously recorded during the analysis, at least while the dimensional change is being observed and / or measured. A connection can also be made between the continuously recorded temperature and / or temperature change with the dimensional change and the duration of the respective shrinking process. Material characteristics of the thermoplastic packaging material can also be derived from the context.

It may be that the temperature and / or the change in temperature of the sample is / are recorded via one or more infrared sensors as part of the analysis. The one or more infrared sensors can be designed as part of the device for determining material characteristics of the thermoplastic packaging material. Furthermore, the one or more infrared sensors can be arranged above the sample piece, the respective sample piece being located in the detection range of the one or more infrared sensors. Advantageously, when using one or more infrared sensors, no direct contact of sensors with the specimen is necessary, so that the dimensional change of the specimen during the advancing shrinking process is recorded in an unadulterated manner and is not influenced by contact with sensors. The previously mentioned receptacle, in which the sample piece can be arranged, can advantageously be located below the one or more infrared sensors.

It may also be the case that the sample piece is placed on a carrier substrate as part of the analysis, which for thermal purposes transfers thermal energy to the respective sample piece or transfers thermal energy to the respective sample piece. When the specimen is placed on the respective carrier substrate, the specimen can be in surface contact with the carrier substrate via one of its broad side surfaces, while the further opposite broad side surface of the specimen has no surface contact with the carrier substrate. The further opposite broad side surface can in this case possibly face the one or more infrared sensors and / or one or more further sensors. In preferred embodiments, a broad side surface of the respective sample piece is completely in surface contact with the carrier substrate.

In preferred embodiments, the carrier substrate can be formed by a liquid medium, such as oil or the like. The viscosity of the carrier substrate or of the liquid medium should preferably be chosen such that the Sample piece can be carried over the carrier substrate without a surface contact of the sample piece with a heating plate possibly arranged below the carrier substrate and / or a receptacle possibly arranged below the carrier substrate for the sample piece is formed. This prevents the respective specimen from sticking to the heating plate or to the receptacle.

Accordingly, the respective carrier substrate can be designed, for example, as an oil film. The respective sample piece can be carried in a floating manner by being placed on the respective carrier substrate after being placed on the respective carrier substrate, but cannot be completely immersed in the carrier substrate. If the specimen undergoes a change in dimension during a progressive shrinking process, the respective specimen can at least largely move without any frictional resistance due to the floating bearing on the carrier substrate. A very precise recording of the shrinkage characteristics or of the material characteristics without falsifying the measurement results is possible when the carrier substrate is formed using a liquid medium, preferably oil. There is also the possibility of forming the carrier substrate using further materials or substances, such as talcum. The respective carrier substrate can in this case be heated via the temperature control device or, if appropriate, via a heating plate, and can transmit thermal energy to the sample.

In further embodiments, it is conceivable that the sample piece is areally connected to a dimensionally stable material as part of the analysis before heating, which dimensionally stable material is designed such that it experiences no or essentially no dimensional change when the sample piece is heated. For example, the dimensionally stable material can be glued to the specimen. The dimensionally stable material can preferably be glued onto at least one broad side surface of the specimen. In particular, the dimensionally stable material can be glued onto the at least one broad side surface in such a way that it extends across the entire broad side surface. It is conceivable, for example, that the dimensionally stable material is designed as a strip or strip-like.

In various embodiments, it can be provided here that the respective sample piece is connected in the course of the analysis to a plurality of units made of dimensionally stable materials or to a number of units made of dimensionally stable materials which may be strip-shaped. For example, the units made of dimensionally stable materials can be arranged in edge areas of the respective specimen. Further embodiments are conceivable in which the dimensionally stable materials, which may be in the form of strips, are oriented perpendicular to one another, for example, and / or are applied to the respective specimen in further orientations.

Since the dimensionally stable material represents a resistance for the thermoplastic material of the specimen in the event of shrinkage, resistances for thermoplastic packaging materials occurring during the shrinking process can be simulated by means of articles or containers. Precise statements on the behavior of the thermoplastic packaging material or the shrink film when shrinking onto articles can be made by connecting the sample with dimensionally stable material.

In further embodiments, it is conceivable that the two units made of dimensionally stable material are applied to different areas of the specimen during the analysis, the two units being held stationary when the specimen changes dimensions. For example, the two units made of dimensionally stable materials can be clamped in a receptacle of the device described in more detail below. If the specimen undergoes a shrinkage process as a result of the heating, the specimen is possibly stretched to breakage due to the fixed arrangement of the two units made of dimensionally stable materials. Taking into account the dimensional change in elongation and the resulting breakage, further statements can be made about the behavior of the respective thermoplastic material when shrinking. If necessary, material characteristics can be derived from the statements. Further embodiments in which more than two units made of dimensionally stable material are applied to the respective specimen are also conceivable.

It may also be the case that, as part of the analysis, a first sample of the thermoplastic packaging material is partially connected to the dimensionally stable material before heating and a second sample of the thermoplastic packaging material is not brought into connection with the dimensionally stable material. The first and the second sample piece can be heated at the same time and a connection can be made taking into account the dimensional changes of the first and the second sample piece in the advancing shrinking process, the respective temperature and / or temperature change of the first and the second sample piece in the shrinking process and the duration of the shrinking process. More detailed statements on the behavior of the respective thermoplastic material when shrinking onto articles can be made meet in a time-optimized manner by means of this embodiment. Material characteristics for various embodiments of the method according to the invention, various embodiments of the shrink tunnel according to the invention and / or for various embodiments of the packaging system according to the invention can furthermore be derived from the statements regarding the behavior of the respective thermoplastic material when shrinking onto articles.

Provision can further be made for the dimensional change of the sample piece to be observed in the course of the shrinking process in the course of the analysis by means of optical detection and preferably via one or more camera systems. The camera systems can be arranged above the sample and, for example, adjacent to or in the area of an infrared sensor for determining the temperature and / or temperature change of the sample. In order to ensure that the respective dimensional change of the specimen in the shrinking process proceeds as accurately as possible, the previously described embodiments in which the respective specimen is placed on a substrate formed by oil or talc and held by the substrate have proven successful. The broad side surface of the sample piece facing away from the substrate is in the detection area of the one or more camera systems, so that a change in dimension of the respective sample piece over the course of time can be completely detected by the one or more camera systems. Since the sample piece may be placed floating on the carrier substrate and a broad side surface of the respective sample piece facing the camera system or the one or more infrared sensors is preferably not brought into contact with the carrier substrate, a very precise detection of dimensional changes can be carried out in such an embodiment of the present invention of the respective sample and the temperature and / or temperature change of the respective sample.

In order to further improve the detection of the respective dimensional change, it can be provided that at least one visual identification is applied to the respective sample piece for the optical recognition of the dimensional change. The dimensional change can be optically recognized, if necessary by the one or more camera systems, taking into account the visual identification. The term “visual marking” can be interpreted broadly so that any surface of the sample can have a “visual marking” according to the definition, in which at least one broad side surface of the sample or the broad side surface of the sample pointing in the direction of the camera system has a reduced or increased contrast in some areas owns.

As already mentioned above, the device for determining material characteristics on thermoplastic packaging material to be shrunk on articles can include a receptacle for a sample piece of the respective thermoplastic packaging material. The recording can be accessible from the outside. In preferred embodiments, the sample piece can be inserted or inserted into the receptacle of the device for determining material characteristics on thermoplastic packaging material to be shrunk on articles.

The device for determining material characteristics on articles to be shrink-wrapped on packaging material can also include a temperature control unit which, with the receptacle for heating the specimen, above a shrinkage temperature effective for the respective material of the specimen or a temperature at which the specimen changes to the thermoplastic aggregate state Connect. For example, the temperature control unit can have a heating plate which comprises the receptacle and / or with which a receptacle of the specimen is brought into surface contact in order to receive thermal energy. It is also conceivable that the temperature control device comprises heating elements, such as heating wires or the like.

The device for determining material characteristics on thermoplastic packaging material to be shrink-fitted on the article and the shrink tunnel can form a structural unit. It is therefore conceivable that the device for determining material characteristics of the thermoplastic packaging material to be shrink-fitted onto the article is structurally integrated in the shrink tunnel. Thus, the device for determining material characteristics of the thermoplastic packaging material to be shrunk onto articles and the shrink tunnel can be mechanically coupled to one another. The device for determining material characteristics of the thermoplastic packaging material to be shrunk onto articles and the shrink tunnel can be set up locally next to one another or positioned locally next to one another. Embodiments have proven successful in which the shrink tunnel and the device for determining material characteristics are each designed as modules, which together can form at least part of a complete packaging system.

The device for determining material characteristics on articles to be shrunk on thermoplastic packaging material can be one Detection device for measuring and / or observing a progressive dimensional change of a sample of the thermoplastic packaging material over the course of time during a shrinkage process resulting from the heating. The detection device can be arranged above the previously mentioned receiving area for the sample.

It is also conceivable that an optical detection device is provided, by means of which packaging material shrunk onto articles can be checked with regard to predetermined quality characteristics. If it is determined in the course of such a check that quality characteristics of the packaging material shrunk onto the article deviate from the specified quality characteristics, a regulation for the shrink tunnel can be initiated. It may be the case that the different temperature levels with which the thermoplastic packaging material is acted upon and which are matched to the determined and / or known material characteristics are regulated taking into account the deviation ascertained. It may also be the case that the amount of shrink medium applied to the thermoplastic packaging material during the movement through the shrink tunnel is increased or decreased, taking into account the determined deviation. The shrink tunnel can have several throttle valves to increase or decrease the amount of shrink medium, the position of which is adapted to increase or decrease the amount of shrink medium.

One or more means for detecting a temperature and / or temperature change of the specimen in the shrinking process can also be provided as part of the device for determining material characteristics of packaging material to be shrunk on articles. The one or more means for detecting a temperature and / or temperature change of the sample piece can comprise at least one temperature sensor which is connected to the respective sample piece for detecting its respective actual temperature.

The device for determining material characteristics of the packaging material to be shrunk onto articles can also comprise a computer-aided unit which is equipped with the one or more means for detecting a temperature and / or a change in temperature of the sample as well as with the at least one detection device for measuring and / or observing a change in dimension of the respective sample is brought into operative connection.

For this purpose, the computer-aided unit can be coupled to the one or more means and / or to the at least one detection device for exchanging data wirelessly or via a cable connection. In this case, data relating to the respective temperature and / or a respective temperature change of the sample piece can be sent to the respective computer-aided unit or received by the respective computer-aided unit. Data on the respective dimensional change can also be sent from the detection device to the computer-aided unit or received by the respective computer-aided unit.

It may be the case that the computer-aided unit is also coupled to the shrink tunnel and can control and / or regulate the different temperature levels in a manner coordinated with the respective material characteristics, which were determined via the device for determining material characteristics.

Furthermore, it may be that a correlation can be established from the duration of the shrinkage process, the recorded temperature and / or temperature change of the sample in the shrinking process and the dimensional change of the sample proceeding over time, and material characteristics can be derived from it via the computer-aided unit .

In addition, it may be that the connection established via the computer-aided unit or the material characteristics derived therefrom can be optically represented by a display which may be connected to the computer-aided unit.

In preferred embodiments, it can further be provided that the device for determining material characteristics on thermoplastic packaging material to be shrink-fitted on articles has a storage unit coupled to the computer-aided unit, on which the connection or material characteristics produced in each case can be stored by the computer-aided unit. In this case, an assignment of the connection made in each case or the respective material characteristics to the respective sample piece and in this case to the respective thermoplastic packaging material can take place before storage. A later access to the respective material characteristics of a thermoplastic packaging material is possible due to the assignment.

It can be provided that the computer-aided unit is connected to the previously mentioned temperature control unit for heating the sample. Next can be provided be that the temperature of the specimen is at least largely kept constant during the measurement and / or observation of the advancing dimensional change or is changed in a defined manner during the measurement and / or observation of the advancing dimensional change. If a temperature and / or temperature change is continuously measured while measuring and / or observing the progressing dimensional change, the temperature-controlled unit can be controlled at least approximately in real time via the computer-aided unit, depending on the respective actual temperature of the sample.

Furthermore, it can be provided that the computer-aided unit starts to measure and / or observe the respective dimensional change after the sample piece has been heated at a fixed temperature of the sample piece. For example, the set temperature can be designed as a shrinkage temperature effective for the respective specimen.

In further embodiments, it can also be provided that the one or more means for measuring and / or detecting a temperature and / or temperature change of the sample piece comprise at least one infrared sensor. The infrared sensor can be arranged above the specimen or above the receptacle for the respective specimen and can be connected wirelessly or in a wired manner to the computer-aided unit for transmitting data on the respective temperature and / or temperature change of the specimen.

As already mentioned above, the at least one detection device for detecting a change in dimension of the sample can comprise at least one camera system. Likewise, the camera system can be arranged above the receptacle for the respective sample and can be connected wirelessly or wired to the computer-aided unit for transmitting data with regard to the dimensional change of the respective sample.

Furthermore, the sample piece can be placed in the receptacle on a carrier substrate which is connected to a heating plate of the temperature unit in order to transmit thermal energy to the respective sample piece. The carrier substrate can thus be applied flat to the heating plate.

Embodiments have proven particularly useful in which the computer-aided unit is connected to a control and / or regulating device of the shrink tunnel in order to pass on information about the connection established and the material characteristics derived therefrom. A connection between the computer-aided unit and the control and / or regulating device of the shrink tunnel can be made by means of a cable connection and / or wirelessly. It is conceivable, for example, that during operation of the shrink tunnel and / or operation of the shrink tunnel, a previously described connection is established from the change in dimension of the sample, the duration of the shrinking process and the temperature and / or temperature change of the sample, the control device of the shrink tunnel using the connection is informed and regulation or control of the shrink tunnel taking into account the information with the at least two different temperature levels already described.

Embodiments have also proven themselves in practice, in which the temperature control unit, which may be designed as part of the device for determining material characteristics, is formed by an electrically and / or gas-operated heater.

• 1 zeigt beispielhaft einen Längsschrumpf sowie einen Querschrumpf als jeweiliges Materialcharakteristikum unterschiedlicher thermoplastischer Verpackungsmaterialien in Abhängigkeit der jeweiligen Schrumpfungstemperatur,
• 2 zeigt beispielhaft den Längsschrumpf als Materialcharakteristikum sowie den Querschrumpf als weiteres Materialcharakteristikum eines thermoplastischen Verpackungsmaterials aus der Praxis.
• 3 zeigt eine schematische Ansicht eines Ausführungsbeispiels eines erfindungsgemäßen Verpackungssystems für Artikel. Weiter verdeutlicht 3 einzelne Schritte, wie sie in diversen Ausführungsformen des erfindungsgemäßen Verfahrens vorgesehen sein können.
• 4 zeigt eine vergrößerte Ansicht des Ausschnitts A aus 3.
• 5 zeigt eine schematische Draufsicht auf die Ausführungsform einer als Bestandteil eines Verpackungssystems ausgebildeten Einrichtung zum Feststellen von Materialcharakteristika entsprechend 3.
• 6 zeigt eine beispielhafte Ausführungsform eines Probenstücks vor und nach Erwärmung durch eine Einrichtung zum Feststellen von Materialcharakteristika.
• 7 zeigt eine schematische Ansicht einer weiteren beispielhaften Ausführungsform eines Probenstücks.
• 8 zeigt eine schematische Ansicht einer weiteren beispielhaften Ausführungsform eines Probenstücks.
• 9 zeigt eine schematische Ansicht eines Probenstücks bei Umsetzung von möglichen Ausführungsformen eines erfindungsgemäßen Verfahrens.
• 10 zeigt eine Ausführungsform eines erfindungsgemäßen Schrumpftunnels, wie er auch bei dem Verpackungssystem aus dem Ausführungsbeispiel nach 3 sowie zur Umsetzung in diversen Ausführungsformen des erfindungsgemäßen Verfahrens vorgesehen sein kann.

In the following, exemplary embodiments are intended to explain the invention and its advantages with reference to the attached figures. The size relationships of the individual elements to one another in the figures do not always correspond to the real size relationships, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

• 1 shows an example of a longitudinal shrink and a transverse shrink as the respective material characteristic of different thermoplastic packaging materials depending on the respective shrinking temperature,
• 2nd shows an example of longitudinal shrinkage as a material characteristic and transverse shrinkage as a further material characteristic of a thermoplastic packaging material from practice.
• 3rd shows a schematic view of an embodiment of an inventive packaging system for articles. Clarified further 3rd individual steps, as can be provided in various embodiments of the method according to the invention.
• 4th shows an enlarged view of section A from 3rd .
• 5 shows a schematic top view of the embodiment of a device designed as part of a packaging system for determining material characteristics accordingly 3rd .
• 6 shows an exemplary embodiment of a sample piece before and after heating by a device for determining material characteristics.
• 7 shows a schematic view of a further exemplary embodiment of a sample piece.
• 8th shows a schematic view of a further exemplary embodiment of a sample piece.
• 9 shows a schematic view of a sample piece when implementing possible embodiments of a method according to the invention.
• 10th shows an embodiment of a shrink tunnel according to the invention, as it also in the packaging system from the embodiment of 3rd and can be provided for implementation in various embodiments of the method according to the invention.

Identical reference numerals are used for identical or identically acting elements of the invention. Furthermore, for the sake of clarity, only reference numerals are shown in the individual figures which are necessary for the description of the respective figure. The illustrated embodiments merely represent examples of how the device according to the invention or the method according to the invention can be designed and do not constitute a final limitation.

The embodiments, examples and variants of the preceding paragraphs, the claims or the following description and the figures, including their different views or respective individual features, can be used independently of one another or in any combination. Features described in connection with one embodiment are applicable to all embodiments unless the features are inconsistent.

Although “schematic” representations and views are generally used in the context of the figures, this does not mean in any way that the figure representations and their description should be of secondary importance with regard to the disclosure of the invention. The person skilled in the art is quite capable of extracting enough information from the schematically and abstractly drawn representations that facilitate his understanding of the invention, without his understanding being impaired in any way from the drawn and possibly not exactly to scale proportions . The figures thus enable the person skilled in the art as a reader, on the basis of the specifically explained implementations of the method according to the invention and the specifically explained mode of operation of the packaging system according to the invention and the shrink tunnel according to the invention, to gain a better understanding of the general and / or abstract formulated in the claims and in the general part of the description Derive ideas of invention.

The schematic view of the 1 shows the longitudinal shrinkage as an example LS as well as the transverse shrink QS several thermoplastic packaging materials depending on the respective shrinking temperature or depending on the respective temperature level. This is the longitudinal shrinkage in the above coordinate system LS several thermoplastic packaging materials 22 (see. 10th ) shown, the temperature on the abscissa and the respective shrinkage of the thermoplastic material on the ordinate 22 are registered.

How very good in 1 As can be seen, there are thermoplastic packaging materials that show almost no shrinkage behavior at a temperature of 120 ° C, while a shrinking process for other thermoplastic packaging materials starts at a temperature of approx. 110 ° C. The longitudinal shrinkage LS Knowing thermoplastic packaging materials as a material characteristic in the respective shrinking process is crucial to shrinking thermoplastic packaging materials 22 on article 2nd (see. 10th ) to be able to train optimally. If the longitudinal shrinkage LS is not known, this can be done, for example, by means of a device for determining material characteristics 10th to 3rd be determined.

The complexity of shrinkage processes is further exacerbated by the in 2nd cross shrinkage shown QS clarifies. Here, too, the temperature is plotted on the abscissa and the shrinkage for the respective thermoplastic packaging material is plotted on the ordinate. If a temperature of approx. 110 ° C is exceeded, various thermoplastic materials first show an expansion before they shrink to a certain level. The transverse shrinkage varies with all materials QS depending on the temperature. Various materials show an at least approximately linear increase in shrinkage over a certain temperature range, while no further linear increase in shrinkage is observed for other materials. Also with regard to cross shrinkage QS There is therefore a need for thermoplastic materials to know the behavior under the influence of temperature or the behavior as a function of the respective intrinsic temperature as precisely as possible in order to avoid a shrinkage of To be able to train blanks of thermoplastic packaging material optimized for articles.

The 2nd shows the longitudinal shrinkage as an example LS as well as the transverse shrink QS a thermoplastic film from practice. The temperature of the respective thermoplastic packaging material is also plotted on the abscissa, while the percentage shrinkage of the material is set on the ordinate. Reference number 7 refers to a theoretical process window in which shrinking processes of thermoplastic films onto articles take place in practice.

In the area shown, the temperature is too low around a transverse shrink QS to train for the thermoplastic packaging material shown as an example. However, the material shows in the temperature range of the theoretical process window 7 an expansion of the thermoplastic material between 0 and 10%.

Taking into account the longitudinal shrinkage shown as an example LS shrinkage can already be seen above a temperature limit of 100 ° C, which is evident in the process window 7 increases rapidly and changes when you leave the theoretical process window 7 and levels off at a temperature of approx. 120 ° C to a constant value between 70% and 80%.

Because the longitudinal shrinkage LS and the cross shrink QS , as in 2nd To recognize that they are designed very differently and this often leads to insufficient shrinkage quality in practice, devices and methods are desirable with which the shrinkage quality can be further improved.

The 3rd shows a schematic view of an embodiment of a packaging system according to the invention 1 for items 2nd (see. 10th ). Clarified further 3rd individual steps, as can be provided in various embodiments of the method according to the invention. The packaging system 1 comprises a device for determining material characteristics on thermoplastic packaging material to be shrink-fitted 10th as well as a shrink tunnel 100 . The shrink tunnel 100 and the device for determining material characteristics on thermoplastic packaging material to be shrink-fitted 10th are in active connection with one another, as described below.

A sample 5 of the respective thermoplastic packaging material, which is available for shrinking onto the article, is shown in the 3rd already in the recording 11 the device for determining material characteristics 10th used. The material of the sample 5 is identical to the material of the thermoplastic packaging material to be shrunk onto the article.

The recording 11 the device for determining material characteristics 10th is accessible from the outside, so that one person takes the respective sample 5 in the recording 11 the device for determining material characteristics 10th can insert or insert. For heating the sample 5 is the recording 11 with a heater 9 in operative connection, which in the present case is an electrical heater 14 is trained. The heater 9 forms on their the reception 11 facing side a temperature-controlled heating plate, which with the recording 11 for heating the sample 5 is brought into extensive contact. This type of temperature control is only to be understood as an example. It is also conceivable, for example, that the sample 5 is heated via an oil bath and / or via a hot air stream and / or other means for applying thermal energy.

About the heater 9 is the recording 11 temperature controlled so that the sample 5 above one for the respective sample 5 effective shrinkage temperature is heated.

The device for determining material characteristics also comprises 10th a detection device 13 . Via the detection device 13 becomes a dimensional change of the specimen 5 observed after heating above the respective shrinking temperature over time. The detection device 13 is present as a camera system 16 trained and stands with a computerized unit 17th in connection which computerized unit 17th Data on the dimensional change of the sample that changes over time 5 from the detection device 13 or the camera system 16 receives and from this derives material characteristics of the thermoplastic packaging material or thereby determines material characteristics of the thermoplastic packaging material.

As in 3rd the detection device can be seen 13 above the recording 11 or above the sample 5 arranged and has a detection area EB that is in the whole in the recording 11 inserted sample 5 extends.

They are also means 15 for detecting a temperature and / or temperature change of the sample 5 shown. The means 15 are present by one or more infrared sensors 18th educated. It is advantageous through the formation of the means 15 via infrared sensors 18th not a direct one Contact with the sample 5 necessary to be able to record the respective temperature and / or temperature change. The dimensional change of the sample 5 is therefore not falsified in the event of shrinkage or by contact of sensors with the sample 5 unaffected.

The means are also there 15 or the infrared sensors 18th with the computerized unit 17th connected, the computerized unit 17th when detecting the dimensional change of the specimen 5 Data on the respective dimensional change from the infrared sensors continuously over the course of time 18th receives. Taking this data into account, the computer-aided unit can derive material characteristics of the thermoplastic packaging material or determine material characteristics of the thermoplastic packaging material.

Thus, the computerized unit 17th a connection from a duration of the shrinking process, which means 15 detected temperature and / or temperature change of the sample 5 in the shrinking process as well as the dimensional change of the sample progressing over time 5 manufacture and possibly as material characteristics on a display unit 21st represent. It is conceivable that a user is on the display unit 21st material characteristics shown in a control and / or regulating device of a shrink tunnel 100 manually.

Furthermore, the material characteristics in conceivable embodiments can be determined by an in 2nd Printing device, not shown, are output as well with the computer-aided unit 17th communicates. The computer-based unit also has 17th a storage unit, on which the connection or material characteristics established in each case are stored. An assignment of the material characteristics to the respective sample piece can be made beforehand 5 or to the respective thermoplastic packaging material of the sample 5 getting produced.

To make precise statements about the behavior of the sample 5 or the thermoplastic packaging material of the sample 5 To be able to meet over time, the temperature of the sample 5 about the means 15 or the infrared sensors 18th at least during the dimensional change of the sample 5 continuously recorded to the computer-aided unit 17th transferred and taken into account when establishing the connection. One or more material characteristics can be derived from this.

It can further be provided that the device for determining material characteristics 10th forms a control loop in which the heating device 9 via the computerized unit 21st with the means 15 or the infrared sensors 18th is brought into operative connection.

For example, it is conceivable that the temperature of the sample 5 over the course of time when the dimensional change of the sample is recorded 5 should be kept at least largely constant. If the actual temperature of the sample is too low or too high 5 about the means 15 can be recorded via the computer-aided unit 17th the heater 9 for the defined adjustment of the temperature of the sample 5 can be controlled. The control or temperature control can take place at least approximately in real time. The material characteristics determined thereby provide very precise information about the actual behavior of the thermoplastic packaging material when shrinking onto articles in the subsequent shrinking process.

In further embodiments, it may be that the respective temperature or the temperature level of the sample 5 during the dimension change should be raised and lowered in a defined manner. Here too, the respective actual temperature of the sample can be recorded 5 about the means 15 or the infrared sensors 18th done and the heater 9 via the computerized unit 17th to adjust the respective temperature of the sample 5 can be controlled.

The packaging system 1 also includes a shrink tunnel 100 which in 3rd is only shown schematically and with the computer-aided unit 17th communicates. An embodiment of a shrink tunnel 100 as for the embodiment of a packaging system 1 to 3rd can be provided is detailed in 10th to recognize.

The shrink tunnel 100 reproduces in the embodiment 3rd or. 10th only two heating zones HZ1 and HZ2 (see. 10th ), which is in a direction of movement of the shrink tunnel intended for articles 100 successive. In further embodiments, however, it is conceivable that the shrink tunnel 100 more than two heating zones HZ1 and HZ2 or forms at least three heating zones in a direction of movement of the shrink tunnel provided for the article 100 successive. In a direction of movement of the shrink tunnel intended for articles 100 The heat-shrinking process, in which the thermoplastic packaging material is placed within the theoretical process window, can take place at the last arranged heating zone 7 (see. 2nd ) is heated temperature and is shrunk onto the article. All of the at least three heating zones can form different temperature levels, which different temperature levels are matched to established and / or known material characteristics of the thermoplastic packaging material.

The first heating zone HZ1 has in the embodiment of the 3rd or. 10th opposite the second heating zone HZ2 a different temperature level with which the thermoplastic packaging material is heated. It is provided that the thermoplastic packaging material in the first heating zone HZ1 is preheated so that the thermoplastic packaging material when passing from the first heating zone HZ1 in the second heating zone HZ2 has a temperature at which neither the longitudinal shrinkage described above LS still the previously mentioned transverse shrinkage QS have started. The thermoplastic packaging material preferably has a transition from the first heating zone HZ1 in the second heating zone HZ2 a temperature which is in relation to the longitudinal shrinkage not yet used LS (see. 1 and 2nd ) and the transverse shrinkage not yet used QS is slightly below the respective temperature at which the longitudinal shrinkage LS and the cross shrink QS starts. The thermoplastic packaging material is thus in the first heating zone HZ1 warmed or preheated for later shrinking onto articles.

The thermoplastic packaging material is then shrunk onto the respective articles in the second heating zone HZ2 . A temperature level of the second heating zone HZ2 is compared to a temperature level of the first heating zone HZ1 trained. The temperature level of the second heating zone HZ2 is within the theoretical process window as in 2nd by reference with number 7 is shown, however, in various further embodiments it can also be above a temperature provided for the theoretical process window. On the other hand, the thermoplastic packaging material is in the first heating zone HZ1 a temperature at which the thermoplastic packaging material covers the theoretical process window 7 not reached. If more than two heating zones are provided, then, as already mentioned above, in one with regard to the direction of movement of the shrink tunnel provided for the articles 100 the heating zone arranged last, the actual shrinking process takes place, in which the thermoplastic packaging material shrinks onto articles. The thermoplastic packaging material can be preheated in all further heating zones upstream of this heating zone, the temperature of the thermoplastic packaging material being the theoretical process window 7 (see. 2nd ) not reached.

Practice has shown that with such preheating of the thermoplastic packaging material and subsequent shrinking of the preheated thermoplastic packaging material onto articles, containers can be produced in which the shrunk-on thermoplastic packaging material has no or only a very slight wrinkling or defect. The different temperature levels for the first heating zone HZ1 and the second heating zone HZ2 To be able to define defined material characteristics of the thermoplastic packaging material in advance by means of the device 10th detected. The computer-aided unit then controls taking into account the determined material characteristics 17th the shrink tunnel 100 such that the in the heating zones HZ1 and HZ2 trained different temperature levels are matched to the determined material characteristics of the thermoplastic packaging material. It may be the shrink tunnel 100 has a separate or separate control and / or regulating device. Then the computerized unit 17th with the separate or own control and / or regulating device of the shrink tunnel 100 are connected and the separate control and / or regulating device of the shrink tunnel the different material characteristics or the different temperature levels to be coordinated therewith for the first heating zone HZ1 and the second heating zone HZ2 pretend.

The 4th shows an enlarged view of section A from 3rd . The heater can still be seen 9 which as electrical heating 14 is formed as well as the flat with the heating device 9 contacting recording 11 . Also the sample 5 which in the recording 11 is inserted.

The 4th further shows the sample 5 and recording 11 intermediate carrier substrate 19th , which in the present case is designed as an oil film, but in further embodiments can be formed by alternative carrier materials, such as talcum. The carrier substrate can also 19th in further embodiments, for example, be formed by tempered air. The sample 5 is in 4th with one of its broad side surfaces on the carrier substrate 19th applied and is from the carrier substrate 19th worn such that there is no direct contact or surface contact with the recording 11 and the heater 9 owns. Only a broad side surface of the specimen 5 is here with the carrier substrate 19th in surface contact while the other opposite broad side surface of the sample 5 no surface contact with the carrier substrate 19th owns and the detection device 13 as well as the infrared sensors 18th (see. 4th ) is facing.

Because the sample 5 with one of its broad side surfaces completely with the carrier substrate 19th is in contact, can be via the heater 9 thermal energy to the intake 11 passed on from the recording 11 to the carrier substrate 19th transferred and the sample 5 over the carrier substrate 19th be heated evenly.

The 5 shows a schematic plan view of the embodiment of a device for determining material characteristics 10th out 3rd . In 5 are still the heating device 9 to recognize the recording 11 , which is flat with a heating plate of the heating device 9 is contacted, the carrier substrate 19th as well as that in the recording 11 inserted sample 5 .

The sample 5 in the present case has a square geometry and is essentially flush with the receptacle before heating 11 arranged. The geometry of the sample 5 in 5 is to be understood only as an example, so that the sample 5 may have alternative shapes in further embodiments.

Also shows 5 an example of an adjacent arrangement of the means 15 or the one or more infrared sensors 18th and the detection device 13 or the camera system 16 . The means 15 and the detection device 13 are above the recording 11 or the in the recording 11 used sample 5 arranged.

The 6 shows an exemplary embodiment of a sample 5 before heating and an exemplary embodiment of a sample 5 ' after heating and shrinking.

The shrinkage of the specimen 5 is off according to the diagram 1 in a temperature range between 110 ° C and 115 ° C. The temperature ranges are only to be understood as examples, so that further thermoplastic packaging materials are distinguished by a respective effective shrinkage temperature, which differs from the example 1 differs. As can also be seen in the diagram, there is a longitudinal shrinkage in the selected temperature range LS of the sample 5 to be recorded.

A cross shrink QS does not take place in the temperature range between 110 ° C and 115 ° C, but there is a slight transverse expansion QD between 0% and 10% of the sample 5 . By means of the device for determining material characteristics 10th as exemplified in 3rd was shown, it is possible to shrink both the longitudinal LS as well as the transverse stretch QS to be recorded and as separate material characteristics for coordinated control of different temperature levels of several heating zones HZ1 or. HZ2 (see. 10th ) of a shrink tunnel 100 to use.

The 7 shows a schematic view of a further exemplary embodiment of a sample piece 5 how it can be used for implementation in various embodiments of the method according to the invention.

The sample 5 is on two opposite edges with a dimensionally stable material 23 and 23 ' associated which dimensionally stable material 23 and 23 ' when the sample is heated 5 about the heater 9 undergoes no dimensional change. The dimensionally stable material is present 23 and 23 ' strip-shaped and on the sample 5 or on the thermoplastic material of the sample 5 glued.

Two possible dimensional changes of the sample 5 as they depend on each for the specimen 5 selected thermoplastic material can be found in 7 shown on the right.

The first sample shown on the right shows 5 ' a dimensional change in which a shrinking process of the specimen 5 ' in the field of dimensionally stable materials 23 and 23 ' is small and from a certain distance from the dimensionally stable materials 23 and 23 ' increases strongly each time. From a certain distance from the dimensionally stable materials 23 and 23 ' is the shrinkage of the sample 5 ' constantly trained.

The further sample 5 " shows a dimensional change in which the shrinkage of the specimen 5 " towards away from dimensionally stable materials 23 and 23 ' runs in a curve. Opposite the sample 5 ' is the shrinkage in the area of dimensionally stable materials 23 and 23 ' with sample 5 " increasingly trained.

By means of an embodiment of a sample 5 or. 5 ' and 5 " according to 5 as well as dimensionally stable materials 23 and 23 ' Further statements can be made about the behavior of the respective thermoplastic material when shrinking onto articles or about the material characteristics of the respective thermoplastic packaging material.

Because the dimensionally stable materials 23 and 23 ' Just as articles form a resistance when the thermoplastic packaging material shrinks, a shrinking process can which thermoplastic packaging material is shrunk onto the article can be simulated. Information obtained from this can be used as material characteristics to which different temperature levels of several or at least two or possibly at least three heating zones HZ1 and HZ2 (see. 10th ) be coordinated, used.

The 8th shows a schematic view of a further exemplary embodiment of two sample pieces 5 ' and 5 " after one by means for determining material characteristics 10th (see. 3rd ) performed shrinking process.

Just like the sample pieces 5 ' or. 5 " from the embodiment of 7 are on the samples 5 ' and 5 " out 8th dimensionally stable materials 23 or. 23 ' glued. So shows the sample shown on the left 5 ' Dimensionally stable materials oriented perpendicular to each other 23 and 23 ' , each having an axis of symmetry for the sample 5 ' form. The dimensionally stable materials 23 and 23 ' of the sample shown on the left 5 ' intersect and are overlapping on the sample 5 ' glued.

The sample shown on the right also includes 5 " just a strip of dimensionally stable material 23 , which is also used as an axis of symmetry for the sample 5 " is trained.

The embodiments from the 7 and 8th serve only to clarify how, if necessary, dimensionally stable material 23 or. 23 ' for determining material characteristics on specimens 5 or. 5 ' and or 5 " can be applied. It is clear to the person skilled in the art that he uses various types of sample pieces 5 or. 5 ' and or 5 " alternative arrangements of dimensionally stable materials 23 and or 23 ' can provide to by means of a device for determining material characteristics 10th To be able to make statements about the behavior of the respective thermoplastic material when shrinking onto articles.

The 9 shows a schematic view of a sample 5 ' when implementing possible embodiments of a method according to the invention or after exposure to temperature by means of a device for determining material characteristics 10th (see. 3rd ). The sample 5 ' out 9 was already above one for the sample 5 ' effective shrink temperature warmed.

Just like the sample pieces 5 or. 5 ' and 5 " from the embodiment of 7 were on the sample 5 ' from the embodiment of 9 Stiffness of dimensionally stable materials 23 and 23 ' glued in order to be able to determine material characteristics for the thermoplastic packaging material by means of the behavior when heated above the shrinking temperature.

The dimensionally stable materials 23 and 23 ' are in the embodiment 9 stationary in the recording 11 (see. 3rd to 5 ) arranged and can shrink when the specimen 5 ' not together with the sample 5 ' move. Because the sample 5 ' when heated above its effective shrinkage temperature in the longitudinal shrinkage LS contracts, became the sample 5 ' stretched to break due to the shrinking process. Taking into account the dimensional change when connecting the sample 5 ' with stationary in the recording 11 arranged dimensionally stable materials and the onset of breakage when overstretched, further statements can be obtained which, as material characteristics, allow precise predictions on the behavior of the thermoplastic packaging material when shrunk onto articles.

The 10th shows an embodiment of a shrink tunnel according to the invention 100 just like the packaging system 1 from the embodiment 3rd can be provided. Clarified further 10th individual steps as they can be provided in various embodiments of the method according to the invention.

The shrink tunnel 100 includes a housing 27th , through which each article 2nd with thermoplastic packaging material applied in each case 22 be moved. During the movement of the respective article 2nd with the respective applied thermoplastic packaging material 22 through the housing 27th of the shrink tunnel 100 the respective thermoplastic packaging material 22 on the respective article 2nd shrunk. The direction of movement along which the articles 2nd with their respective applied thermoplastic packaging material 22 through the housing 27th of the shrink tunnel 100 is driven with BR indicated.

Inside the case 27th forms the shrink tunnel 100 in the embodiment 10th two in the direction of movement BR offset heating zones HZ1 and HZ2 out. In further embodiments, however, more than two heating zones can also be provided, which are located within the housing 27th are located. The one in the heating zones HZ1 and HZ2 prevailing temperature levels are different and in each case by means of a device 10th (see. 3rd ) determined material characteristics of the thermoplastic packaging material 22 Voted. In the first heating zone HZ1 becomes the thermoplastic packaging material 22 preheated so that the thermoplastic packaging material 22 when leaving the first heating zone HZ1 or when entering the second heating zone HZ2 has a temperature which was still below that for the thermoplastic packaging material 22 effective shrinkage temperature. Only while moving through the second heating zone HZ2 becomes the thermoplastic packaging material 22 on the respective article 2nd shrunk.

Thus the thermoplastic packaging material 22 while moving through the first heating zone HZ1 preheated and during the further movement through the second heating zone HZ2 on the articles 2nd shrunk. Includes the shrink tunnel 100 more than two heating zones, so the thermoplastic packaging material 22 while moving through the shrink tunnel 100 in a certain heating zone on item 2nd shrink on which particular heating zone is in relation to the direction of movement BR as the last or final heating zone in the shrink tunnel 100 is trained. That on article 2nd then shrink-wrapped thermoplastic packaging material 22 has no or only a very slight wrinkling or a small defect.

The 10th also clarifies that the second heating zone HZ2 in the direction of movement BR a cooling zone KU connects. In the area of the cooling zone KU can be arranged a blower device that the article 2nd shrink-wrapped thermoplastic packaging material 22 cools down or supplied with cooling air.

In various embodiments, the already in 3rd Shown device for determining material characteristics of the thermoplastic packaging material 10th in the area of the shrink tunnel 100 erected and / or mechanically with the shrink tunnel 100 be connected. A computerized unit 17th can then be based on established material characteristics of the thermoplastic packaging material 22 different and defined temperature levels for the heating zones HZ1 and HZ2 pretend.

It may also be that the shrink tunnel 100 has a control and / or regulating device, which a user in each case has about the device 10th (see. 10th ) determined material characteristics of the thermoplastic packaging material 22 can manually specify and which control and / or regulating device the different temperature levels for the in 10th shown first heating zone HZ1 and the second heating zone HZ2 or, if necessary, independently controls and / or regulates for more than two heating zones, taking into account the material characteristics specified by a user.

Reference symbol list

1

Packaging system

2nd

items

5

Sample

5 '

Sample (after shrinkage)

5 "

Sample (after shrinkage)

7

Theoretical process window

9

Heater

10th

Device for determining material characteristics

11

admission

13

Detection device

14

Electric heating

15

Means for detecting a temperature and / or temperature change

16

Camera system

17th

Computer-based unit

18th

Infrared sensor

22

Thermoplastic packaging material

23

Dimensionally stable material

23 '

Dimensionally stable material

27th

casing

100

Shrink tunnel

BR

Direction of movement

EB

Detection area

HZ1

Heating zone, first heating zone

HZ2

Heating zone, second heating zone

KU

Cooling zone

LS

Longitudinal shrinkage

QS

Cross shrinkage

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102010032455 A1 [0004]

Claims (16)

Method for shrinking thermoplastic packaging material (22) onto article (2), comprising the following steps: - Moving articles (2) with thermoplastic packaging material (22) applied in each case through a shrink tunnel (100), the thermoplastic packaging material (22) being shrunk onto the articles (2) during the movement through the shrink tunnel (100), and at which procedure is envisaged that - The thermoplastic packaging material (22) during the movement through the shrink tunnel (100) is acted on at different times with at least two different temperature levels, which at least two different temperature levels are matched to established and / or known material characteristics of the thermoplastic packaging material (22). Procedure according to Claim 1 , in which the thermoplastic packaging material (22) during the movement through the shrink tunnel (100) - is first heated to a first temperature level, the thermoplastic packaging material (22) temporally throughout the heating at the first temperature level forming a temperature which is below a temperature ascertained and / or known as the material characteristic of the thermoplastic packaging material (22), at which the thermoplastic packaging material (22) changes to the thermoplastic aggregate state and in which method the thermoplastic packaging material (22) follows in time thereafter and during the further movement by the Shrink tunnel (100) - is heated with a second temperature level, the thermoplastic packaging material (22) temporally during the heating with the second temperature level forming a temperature which is within a material characteristic Cumulative of the thermoplastic packaging material (22) and / or known temperature range is at which the thermoplastic packaging material (22) changes to the thermoplastic aggregate state. Procedure according to Claim 1 or Claim 2 , in which the thermoplastic packaging material (22) during the movement through the shrink tunnel (100) is acted on at a time offset with at least two types of exposure to shrink medium with regard to the amount and / or the direction, which at least two with regard to the The amount and / or the direction of different types of exposure to shrink medium are matched to the established and / or known material characteristics of the thermoplastic packaging material (22). Procedure according to one of the Claims 1 to 3rd , in which a respective period of time, with which the thermoplastic packaging material (22) is acted on at different times during the movement through the shrink tunnel (100) with the respective temperature level, is matched to established and / or known material characteristics of the thermoplastic packaging material (22). Procedure according to one of the Claims 1 to 4th , in which the material characteristics of the thermoplastic packaging material (22) are determined by analyzing a sample (5) of the thermoplastic packaging material (22) before the movement of articles (2) with the thermoplastic packaging material (22) applied through the shrink tunnel (100). Procedure according to Claim 5 , in which the material characteristics determined during the analysis of the sample (5) of the thermoplastic packaging material (22) to which the at least two different temperature levels are matched include one or more of the following material characteristics: - a temperature-dependent shrinkage rate of the thermoplastic packaging material (22 ) over time in a for the movement of the articles (2) through the direction of movement (BR) provided by the shrink tunnel (100); - A temperature-dependent shrink rate of the thermoplastic packaging material (22) over the course of time obliquely to a movement direction (BR) provided for the movement of the articles through the shrink tunnel (100); - a surface tension of the thermoplastic packaging material (22); - a coefficient of friction of the thermoplastic packaging material (22); - A behavior of the thermoplastic packaging material (22) in the case of a material connection with other thermoplastic packaging material (22); - Information on the elongation at break, the modulus of elasticity and / or the tensile strength of the thermoplastic packaging material (22); - Information on the thickness of the thermoplastic packaging material (22). Procedure according to Claim 5 , for which the material characteristics determined during the analysis of the sample (5) of the thermoplastic packaging material (22), to which the at least two different temperature levels are matched, a temperature-dependent shrinkage rate of the thermoplastic packaging material (22) over time in a manner suitable for the movement of the Articles (2) through the direction of movement (BR) provided by the shrink tunnel (100) and a temperature-dependent shrinkage rate of the thermoplastic packaging material (22) over the course of time obliquely to a direction of movement (BR) provided for the movement of articles (2) through the shrink tunnel (100) counting. Procedure according to one of the Claims 5 to 7 , in which after the determination of the material characteristics of the thermoplastic packaging material (22) by analysis of the sample (5) of the thermoplastic packaging material (22) the shrink tunnel (100) is automatically controlled to act on the thermoplastic packaging material (22) with the at least two different temperature levels Which at least two different temperature levels are matched to the determined material characteristics of the thermoplastic packaging material (22). Shrink tunnel (100) for shrinking thermoplastic packaging material (22) onto article (2), which shrink tunnel (100) - Forms at least two heating zones (HZ1, HZ2) offset from one another in a movement direction (BR) of the shrinking tunnel (100) provided for the articles (2) and in which shrinking tunnel (100) it is provided that - The at least two heating zones (HZ1, HZ2) offset from one another in the direction of movement (BR) provided for the article (2) form different temperature levels for heating and shrinking the thermoplastic packaging material (22) onto article (2), which different temperature levels to determined and / or known material characteristics of the thermoplastic packaging material (22) are matched. Shrink tunnel after Claim 9 , at which the different temperature levels of the at least two heating zones (HZ1, HZ2) offset from one another in the direction of movement (BR) provided for the article (2) are matched to established and / or known material characteristics of the thermoplastic packaging material (22) such that - the thermoplastic packaging material (22) forms a temperature when leaving a first heating zone (HZ1), which is below a temperature range determined and / or known as a material characteristic of the thermoplastic packaging material (22) at which the thermoplastic packaging material (22) changes to the thermoplastic aggregate state and wherein - the thermoplastic packaging material (22) forms a temperature in a second heating zone (HZ2), which preferably adjoins the first heating zone (HZ1) in the direction of movement (BR) provided for the articles (2), which temperature is within a as a mate rialcharacteristikum of the thermoplastic packaging material (22) determined and / or known temperature range, at which the thermoplastic packaging material (22) forms the thermoplastic aggregate state. Shrink tunnel after Claim 9 or Claim 10 , in which the at least two heating zones (HZ1, HZ2) offset from one another in the direction of movement (BR) provided for the articles (BR) each have a plurality of nozzles, via which the thermoplastic packaging material (22) can be acted upon with shrinking medium, which respective shrinking medium that forms the respective temperature level of the respective heating zone (HZ1, HZ2), whereby it is provided that - the nozzles of the at least two heating zones (HZ1, HZ2) with respect to the amount and / or the direction of the shrink medium to be dispensed differently and in each case matched to the known ones and / or determined material characteristics of the thermoplastic packaging material (22) can be controlled. Shrink tunnel after one of the Claims 9 to 11 comprising at least one horizontal conveying device, via which the articles (2) with their applied thermoplastic packaging material (22) can be transported through the at least two heating zones (HZ1, HZ2) offset from one another in the direction of movement (BR) provided for the articles (2), wherein It is provided that the at least one horizontal conveyor device can be controlled by the at least two heating zones (HZ1, HZ2) at a transport speed that is matched to the known and / or established material characteristics for moving the articles (2) with the applied thermoplastic packaging material (22). Article packaging system (1) comprising - a shrink tunnel (100) according to one of the Claims 9 to 12 and - a device for determining material characteristics on thermoplastic packaging material (10) to be shrink-wrapped and in which packaging system (1) it is provided that the shrink tunnel (100) and the device (10) are operatively connected to one another in such a way that the shrink tunnel (10) the different temperature levels of the at least two heating zones (HZ1, HZ2) offset in relation to one another in the direction of movement (BR) provided for the article (2) can be matched to the material characteristics of the thermoplastic packaging material (22) determined via the device (10). Packaging system according to Claim 13 , in which the shrink tunnel (100) and the device (10) are operatively connected to one another in such a way that the shrink tunnel (100) the different temperature levels of the at least two heating zones (HZ1.) offset in the direction of movement (BR) provided for the articles (2) , HZ2) can automatically match the material characteristics of the thermoplastic packaging material (22) determined via the device (10). Packaging system according to Claim 13 or Claim 14 , in which the device for determining material characteristics can determine one or more of the following material characteristics: - a temperature-dependent shrinkage rate of the thermoplastic packaging material (22) over time in a movement direction provided for the movement of the articles (2) through the shrink tunnel (100) ( BR); - A temperature-dependent shrinkage rate of the thermoplastic packaging material (22) over the course of time obliquely to a movement direction (BR) provided for the movement of the articles (2) through the shrink tunnel (100); - a surface tension of the thermoplastic packaging material (22); - a coefficient of friction of the thermoplastic packaging material (22); - A behavior of the thermoplastic packaging material (22) in the case of a material connection with other thermoplastic packaging material (22); - Information on the elongation at break, the modulus of elasticity and / or the tensile strength of the thermoplastic packaging material (22); - Information on the thickness of the thermoplastic packaging material (22). Packaging system according to one of the Claims 13 to 15 , in which the device for determining material characteristics (10) can determine the following material characteristics: - a temperature-dependent shrinkage rate of the thermoplastic packaging material (22) over time in a movement direction provided for the movement of the articles (2) through the shrink tunnel (100) ( BR) as a first material characteristic and - a temperature-dependent shrinkage rate of the thermoplastic packaging material (,, 2) over time at an angle to a movement direction (BR) provided for the movement of the articles (2) through the shrink tunnel (100) as an additional second material characteristic.

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