METHOD FOR IDENTIFYING AT LEAST ONE COMPONENT OF A SAMPLE MATERIAL

Description

AREA OF INVENTION

[0001] The invention relates to a method for identifying at least one component of a sample material. GENERAL STATE OF THE ART

[0002] Although the invention may be useful and find application in connection with the identification of components in sample materials of various types and in various fields, the invention and the underlying problem will be explained in more detail below using the example of plastic recycling, without, however, limiting the invention in this respect.

[0003] In the field of plastics recycling, the task often arises of determining the composition of the recycled plastic material, for example, plastic granules, at various stages of the recycling process and obtaining information about the purity of this material as well as the extent of any impurities. In particular, the aim is to detect any undesirable polymer types that may be present in the material under investigation, especially the recycled material.

[0004] Common methods in the field of plastics recycling, primarily intended for sorting the initial material, include IR spectroscopy, the use of cameras in conjunction with image recognition, other optical methods, or separation of materials according to their density. However, none of these conventional methods can cover the entire range of relevant plastics. For example, IR spectroscopy is not sensitive to black plastics. Furthermore, the aforementioned methods are particularly inadequate for analyzing components in compound mixtures, such as for quality control purposes.

[0005] It is known that the method of so-called differential scanning calorimetry (DSC) can be used to determine, for example, melting or glass transition temperatures, particularly of plastics. Based on peaks in the measured quantity obtained using the DSC method, it is possible to deduce the type of plastic under investigation. The differential scanning calorimetry method is fundamentally capable of identifying many plastics and offers high sensitivity.

[0006] In the plastics recycling industry, large quantities of material are processed, which must be checked for purity and composition. However, the material samples analyzed using conventional differential scanning calorimetry (DSC) and the associated equipment are very small, with quantities in the milligram range. Consequently, analyzing a single sample from a large batch of material, such as from a silo filled with plastic granules, using DSC does not provide a reliable, representative picture of the entire batch. Improving the results by analyzing numerous samples from the batch using DSC is very complex and time-consuming.

[0007] In the article "Simultaneous Thermal Analysis of Large Samples" by G. Matuschek et al., Journal of Thermal Analysis, Vol. 47 (1996), pp. 623ff., a device for performing simultaneous thermal analysis (STA) on larger sample weights is described. However, this instrument is relatively expensive to purchase and relatively complicated to use, especially for applications in the recycling sector. Furthermore, sample distribution can be unfavorable. A more cost-effective and easier-to-use approach would be desirable for use in recycling.

[0008] Furthermore, apparatuses known as HFM devices are known, where HFM stands for "heat flow meter." Such an apparatus is conventionally used to measure the heat transfer through a sample, for example, to determine the insulating properties of an insulating material. For this purpose, the sample is placed in the HFM apparatus between two temperature-controlled plates. A temperature gradient is applied to the sample using the plates, and, in a steady state after reaching thermal equilibrium, the heat flow through the sample is measured, thus numerically determining the heat transfer.

[0009] It is also known to measure the specific heat capacity Cp of, for example, a polymer or an insulating material using an HFM apparatus. For this purpose, both plates are initially held at the same temperature, then a short temperature ramp is applied, followed again by isothermal conditions. The integral of the heat flow is then evaluated.

[0010] Furthermore, the technical standard ASTM C1784 describes an operating mode of an HFM apparatus in which both plates are brought to the same temperature, with a stepwise isothermal temperature program serving to determine the heat storage capacity of a sample, in terms of sensible and latent heat.

[0011] WO 2022 / 250533 A1 deals with a method of differential dynamic calorimetry and an apparatus for differential dynamic calorimetry, describing the determination of the thermodynamic properties of a material and its composition. In the procedure described in WO 2022 / 250533 A1, the plate-shaped sample is heated or cooled on one side. On the opposite side of the sample, a plurality of temperature sensors are arranged in a grid pattern.

[0012] Against this background, it would be desirable to be able to accurately characterize a larger batch of a material, for example in the field of plastics recycling, in a simple, easy-to-use, time- and cost-efficient manner, and thereby gain an accurate picture of its composition and any impurities. BRIEF SUMMARY OF THE INVENTION

[0013] Against this background, an object of the invention is to provide an efficient and reliable method by which a sufficiently large sample quantity can be examined in order to characterize a batch of material as representatively as possible. In particular, the method should be suitable and expedient for the accurate characterization of material batches on an industrial scale by means of sampling and analysis.

[0014] According to the invention, this problem is solved by a method having the features of claim 1.

[0015] Accordingly, a method for identifying at least one component of a sample material with which a sample is formed is proposed, the method comprising: Providing the sample, wherein the sample material is formed with a plate- or disk-like geometry or the sample material is arranged in a spatial region with a plate- or disk-like geometry; arranging the sample between two temperature-controlled plate-like elements such that the temperature-controlled plate-like elements extend along each of two opposite main surfaces of the plate- or disk-like geometry; bringing about a temperature change of the sample by bringing about a heat inflow into the sample or a heat outflow from the sample in a symmetrical manner through the two main surfaces of the plate- or disk-like geometry, wherein the temperature change is effected by tempering the plate-like elements and covers a temperature range within which at least one endothermic or exothermic change of the at least one component of the sample material occurs;Determining a heat flow into or out of the sample and obtaining from this a heat flow profile that can be represented as a curve as a function of the temperature of the sample or the temperature-controlled plate-shaped elements, or as a function of time; or determining a temperature of the sample or the temperature-controlled plate-shaped elements and obtaining from this a profile of a time-dependent change in temperature that can be represented as a curve as a function of temperature or as a function of time; comparing the characteristics of a curve, in particular including its shape, of the obtained heat flow profile or the time-dependent change in temperature as a function of temperature or time with the characteristics of a reference curve from one or more reference profiles; and identifying the at least one component of the sample material based on the result of the comparison.

[0016] One of the underlying ideas of the invention is to examine the sample material in a manner fundamentally based on the method of differential scanning calorimetry (DSC), but using a sample containing a much larger quantity of material than in DSC. In this way, it is possible to represent an inhomogeneous composition of the material under investigation, for example, recycled material, in a significantly improved manner and to accurately identify the component(s) of a mixture.

[0017] The invention utilizes a known HFM setup in a DSC-like manner. The HFM apparatus can correspond to, or be similar to, an apparatus as described, for example, in the technical standard ASTM C1784 and the references cited therein. Depending on the sample materials to be examined, the HFM apparatus can be modified, for example, with regard to the temperature range that can be covered. For advantageous applications in the field of plastics recycling, it may be beneficial if the HFM apparatus, by means of modified temperature control devices, allows for a wider temperature range and higher maximum temperatures.

[0018] Advantageously, the method according to the invention, through the substantially symmetrical introduction or removal of heat through the two main surfaces—in other words, the symmetrical application of a heat flow to the sample or the symmetrical imprinting of a temperature change—in conjunction with the plate- or disk-shaped geometry of the sample material or the area in which it is arranged, reduces heat loss to the outside and achieves well-defined temperature gradients and, in particular, a heat flow that is at least approximately one-dimensional in a central region of the sample material. This advantageously contributes to accurate, reliable measurement results and reliable identification of the component(s).

[0019] The plate- or disc-shaped geometry of the sample material is also advantageous in that the endothermic / exothermic process induced by heat input or output within the sample material, such as the melting or glass transition of a component, occurs rapidly, thus preventing the formation of significant temperature gradients and consequently a "melting front" within the sample. This is achieved by the intended geometry, which allows for a large heat input surface despite a relatively large sample weight.

[0020] Furthermore, the present invention advantageously enables the identification of the component(s) without requiring simultaneous measurement on a reference material or a simultaneous blank measurement as a reference. This contributes to a reduction in the equipment required and the associated costs, as well as to a simplification of the method. The identification of the component(s) is thus not only reliable, but also time-saving and easily achievable, and therefore advantageous for use, for example, in the field of plastics recycling or other processes on an industrial scale.

[0021] Advantageous embodiments and further developments of the invention will be found in the dependent claims and in the description with reference to the drawings.

[0022] In one embodiment, when bringing about the temperature change of the sample, the sample material is subjected to a continuous temperature profile, in particular a predefined temperature ramp, preferably a temperature ramp that increases or decreases linearly over time.

[0023] In a further training, the temperature change of the sample is brought about by supplying or removing a constant heat flow from the sample over time.

[0024] According to one embodiment, within the temperature range covered by the temperature change, at least one component of the test material undergoes a phase transition and / or a glass transition. Such changes in the components of the test material with temperature can be readily used to identify one or more components.

[0025] In a training course, the sample material is partially or completely melted or frozen during the temperature change. Melting or freezing, as phase transitions between solid and liquid phases, are also useful for characterizing the component(s) of the sample material.

[0026] In particular, the temperature-controlled, plate-shaped elements are used for heating and / or cooling the sample.

[0027] In one embodiment, the sample material is subjected to two or more temperature change processes by means of temperature-controlled plate-shaped elements, in particular one or more heating processes and one or more cooling processes. This can be used for even better identification of the component(s). Using defined heating and / or cooling rates, the temperature-dependent processes in the sample material can be influenced, depending on the sample material and / or its components. A second heating process, and its evaluation, can be used in particular to establish a uniform initial state, for example by prior melting, and to perform the evaluation starting from such a defined initial state.In particular, the second heating phase, as well as the subsequent cooling phase, during which crystallization can be observed, can be interesting and used to compare the curve's characteristics with those of the reference curve. Such a cooling phase can, for example, provide insights into any additives that may be present in the sample as crystallization accelerators.

[0028] According to one embodiment, the heat flow from the temperature-controlled plate-shaped element into the sample, or vice versa, is detected between the temperature-controlled plate-shaped element and the side of the sample facing the temperature-controlled plate-shaped element in the region of the main surface of the plate- or disk-like geometry adjacent to the temperature-controlled plate-shaped element, in particular by means of a heat flow sensor, for example, a planar heat flow sensor. This enables reliable, accurate, and direct detection of the heat flow. Detection of the heat flow on both sides can also be used, for example, to check the symmetry of the operating mode.

[0029] According to one embodiment, the heat flow sensors are each arranged in a planar area in a central region of one of the main surfaces of the plate- or disk-like geometry, between the temperature-controlled, plate-shaped element adjacent to this main surface and the sample. In particular, the heat flow sensor can occupy a large central region of the main surface. In some exemplary embodiments, the central region of the main surface occupied by the heat flow sensor can, when viewed in relation to the main surface, have a size of at least one-third or at least half of the dimensions of the main surface in each of two coordinate directions, particularly orthogonal ones. In some exemplary embodiments, the central region occupied by the heat flow sensor as a measuring area can, in particular, occupy at least one-ninth, at least one-sixth, or at least one-quarter of the area of ​​the main surface.In this way, the influence of edge effects, which are almost impossible to completely avoid due to the finite size of the sample and the temperature-sensitive plate-shaped elements, can be rendered negligible or nonexistent. A surface area of ​​the heat flow sensor in the aforementioned large central region allows a significant portion of the sample material to be included for accurate data collection. Further increasing the proportion of the main surface occupied by the heat flow sensor as the active measurement area beyond the values ​​mentioned above can be advantageous for achieving even better averaging across potentially inhomogeneous samples.

[0030] In a further development process, one or both of the temperature-controlled plate-shaped elements are moved towards the sample before the temperature change is induced. A predefined force is then applied to the sample in one direction of the plate- or disc-like geometry via the temperature-controlled plate-shaped elements, or a predefined sample thickness is set in the same direction. In this way, defined conditions, such as a defined sample thickness, can be created for the investigation to be carried out, reliable contact with the sample material for defined temperature control can be achieved, and the lowest possible and most uniform thermal resistance at the contact surface can be ensured.

[0031] In one embodiment, the test material is provided with a casing that encloses it within a sealed sample volume. Alternatively, in another embodiment, the test material is surrounded by a flexible sealing element extending along its perimeter in the thickness direction, essentially covering the thickness or filling height of the sample. This sealing element, together with the temperature-controlled, plate-shaped elements, is designed to enclose the sealed sample volume, and is specifically configured to enter into sealing contact with the temperature-controlled, plate-shaped elements. By providing the casing or the sealing element as a kind of rim, the outflow of the liquefied test material upon melting can be prevented.Preferably, the sealing element, by virtue of its flexibility, allows for tracking by moving the plate-shaped element(s) in order to maintain contact between the sample material and the plate-shaped elements during melting.

[0032] According to one embodiment, it is provided that the temperature of the sample is detected on a surface of the sample or in an interior of the sample and / or that the temperature of the temperature-controlled plate-shaped element is detected on a surface of the same or in an interior of the same.

[0033] In further training, the comparison of the curve characteristics and the reference curve characteristics is carried out using corresponding abscissa and / or ordinate values ​​that characterize the curve shape and the reference curve shape at least section by section.

[0034] In further training, the comparison of the curve characteristics and the reference curve characteristics is carried out using at least one characteristic step and / or at least one characteristic extremum, in particular peaks, of the obtained course of the heat flow or the time change of the temperature as well as the reference course, wherein the step or extremum corresponds in particular to a transformation within the sample material.

[0035] In one embodiment, for at least one stage or at least one extremum, in particular a peak, of the obtained profile of the heat flow or the temporal change of the temperature, at least one abscissa value is determined, which corresponds to a starting point or end point or midpoint or inflection point or extremal value assigned to the stage or extremum within the curve shape, and is compared with at least one corresponding abscissa value of at least one reference profile.

[0036] According to a further embodiment, it is provided that for at least one stage of the obtained heat flow profile or the temporal change of temperature, a height of the stage is determined and compared with a height of at least one stage of at least one reference profile, and / or that for at least one extremum, in particular a peak, of the obtained heat flow profile or the temporal change of temperature, the associated extremal value of the heat flow or the temporal change of temperature is determined and compared with an extremal value of at least one extremum, in particular a peak, of at least one reference profile.

[0037] An evaluation of the curve characteristics according to the above explanations and further developments, which can be combined for further improvement, enables a reliable identification of the component(s).

[0038] In this advanced method, at least one characteristic integral value, in particular an area under at least one section of the obtained heat flow or temperature change profile (represented as a curve, for example, under a peak), is determined and compared with a characteristic integral value of the reference profile. In this advanced method, the identification of at least one component of the sample material is additionally carried out based on the result of the comparison of the characteristic integral values. This can contribute to a further improvement in identification. The integral value can correspond to an enthalpy difference, such as during a phase transition in the sample, or to a difference in specific heat capacity, such as during a glass transition in the sample.

[0039] In a further embodiment, the obtained course of the heat flow or the temporal change of the temperature is directly compared with the reference course in their entirety.

[0040] In further training, comparing the curve characteristics, in particular curve shape, and the reference curve characteristics, in particular reference curve shape, involves the use of a pattern recognition algorithm, for example a learning algorithm, and / or an artificial intelligence method.

[0041] Direct comparison and / or the use of pattern recognition or artificial intelligence can further improve the accuracy and reliability of identification.

[0042] According to one embodiment, a multitude of heat flow curves or temperature change over time, each determined in advance for a known sample material or sample material mixture, are used as reference curves.

[0043] According to one embodiment, the reference profiles are provided in the form of a data collection which includes reference profiles of an application-specific selection of pure substances and mixtures, for example plastics and plastic mixtures.

[0044] By drawing on a multitude of reference profiles, for example from a data collection provided in the form of a database, a reliable assessment of a wide range of possible admixtures or impurities in a sample becomes possible. Such a method can prove very useful, for instance, in monitoring recycling processes, where, by their very nature, complete certainty about the starting materials is often difficult to achieve.

[0045] The data collection, such as a database, can be provided on a suitable storage medium or be accessible via a network.

[0046] In a training course, the sample material is provided as a loose material with a large number of individual pieces, for example as granules or a powder.

[0047] In another training course, the sample material is provided as a single, coherent body.

[0048] Providing it as loose material or a solid body allows for its use with different types of samples.

[0049] According to one embodiment, the heat flow or temperature profile is recorded in the absence of a simultaneous reference measurement, particularly using a reference geometrically identical to the sample and made of a previously known material, or by using a blank measurement as a reference, within the same test setup or by means of another identical test setup. This significantly reduces both the equipment and handling effort required for sample analysis, thus contributing to a reduction in costs and time. For example, an empty "twin" of the test setup as a reference is not needed. A simple, targeted analysis of the sample material, avoiding potential sources of error, is therefore possible.

[0050] In one embodiment, the sample under investigation has a mass of more than approximately 10 grams, for example, between approximately 10 grams and approximately 10 kilograms, preferably between approximately 10 grams and approximately 1 kilogram, and more preferably between approximately 10 grams and approximately 200 grams, for example, between approximately 10 grams and approximately 100 grams. Such samples make it possible to obtain a reliable and representative picture of a larger batch of material, such as those found on an industrial scale, for example, in the recycling industry.

[0051] According to further training, the sample material is intended to be a mixture and the method is used to identify one or more materials contained in the sample.

[0052] In an advantageous embodiment, the method is used to determine the purity of a recycled plastic, in particular to identify any admixtures or impurities and / or to determine the extent of these.

[0053] In particular, the process can be used in a process chain for plastics recycling. This allows for time-saving and simple monitoring of the recycling process at various stages, as well as quality control of the resulting end product, such as recycled plastic granules.

[0054] In an exemplary further development, a compounded mixture of materials, in particular a compounded plastic, is provided as the sample material. The invention advantageously makes it possible to examine such a pre-processed plastic with regard to its components. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The invention is described in more detail with reference to exemplary embodiments shown in the accompanying drawings.

[0056] The accompanying drawings are included to facilitate a further understanding of this invention and are incorporated into and form part of this description. The drawings illustrate embodiments of this invention and, together with the description, serve to explain the principles of the invention. Other embodiments of this invention and many of its intended advantages are easily understood when they are better understood by reference to the following detailed description. The elements of the drawings are not necessarily drawn to the same scale. Identical reference numerals denote correspondingly similar parts. Fig. 1 shows a schematic cross-sectional view of an arrangement used to carry out a method according to exemplary embodiments of the invention; Fig. 2 shows, in perspective and schematically, a plate- or disk-like geometry of the sample material used to carry out the method according to the exemplary embodiments, or of a spatial region in which the sample material is arranged to carry out the method according to the exemplary embodiments; Fig. 3 shows an exemplary measurement result obtained by means of the Fig. 1 schematically depicted arrangement and is used according to an exemplary embodiment to identify at least one component of a sample material, exemplified by measurement for a sample of polylactide (PLA); Fig. 4 shows an exemplary measurement result for a polylactide (PLA) obtained by means of a conventional method of differential scanning calorimetry (DSC), with two heatings shown by way of example; Fig. 5 shows an exemplary measurement result obtained by means of the in Fig. 1 The schematically depicted arrangement is obtained and, according to a further embodiment, is used to identify at least one component of a sample material, exemplified by a measurement for a sample of paraffin; Fig. 6 shows an exemplary measurement result for a paraffin obtained by means of a conventional method of differential scanning calorimetry (DSC); Fig. 7 shows a schematic flow diagram of a method according to embodiments of the invention; Fig. 8 schematically illustrates an exemplary enclosure for the sample material for carrying out methods according to embodiments of the invention; and Fig. 9 schematically illustrates a rim-side sealing element for enclosing the sample material, for carrying out methods according to further embodiments.

[0057] In the figures, identical reference numerals denote identical or functionally similar components unless otherwise indicated. All directional terms, such as "top", "bottom", "left", "right", "above", "below", "horizontal", "vertical", "back", "front", and similar terms, are used for explanatory purposes only and are not intended to restrict the embodiments to the specific arrangements shown in the drawings. DETAILED DESCRIPTION OF THE INVENTION

[0058] Fig. 1 Figure 1 shows an arrangement 100 that can be used to carry out methods according to the embodiments of the invention described below. The arrangement 100 serves to examine a sample 1. To provide the sample 1, a sample material, which is taken, for example, from a batch of loose plastic granules obtained from a recycling process, is arranged in a spatial region with a plate- or disc-like geometry 2. For this purpose, the sample material can be placed in a sample frame (not shown in detail) that defines the geometry 2. Alternatively, the sample material of the sample 1 can be a continuous solid body or, alternatively, a compressible body, each having the plate- or disc-like geometry 2, for example, cut accordingly. Fig. 2 Figure 2 schematically illustrates such a plate- or disk-shaped geometry. The geometry 2 is in Fig. 2 The geometry 2 is flat and cuboid-shaped, with the extents of the geometry 2 in the two orthogonal coordinate directions x and y being significantly larger than the extent or thickness t of the geometry 2 in the thickness direction D perpendicular to x and y. The main surfaces 21 and 22 of the geometry 2 are of essentially the same shape and size and are parallel, and in the illustrated embodiment in the Fig. 2 For example, rectangular.

[0059] The sample material of sample 1, regardless of its physical form (e.g., granules, a cohesive body, or otherwise), is in particular a mixture with at least one main material to which one or more other materials may be added due to the recycling process, especially as impurities of the main material, which is desired to be as pure as possible. The sample material thus comprises components, whereby this term refers both to the main component(s) and to any undesirable impurities.

[0060] In the arrangement of 100 of the Fig. 1 The sample 1 is arranged in a sandwich-like manner between two temperature-controlled plate-shaped elements 3 and 4. Furthermore, the arrangement 100 has a heat flow sensor 5 arranged between the main surface 21 of geometry 2 and the plate-shaped element 3, and a heat flow sensor 6 arranged between the main surface 22 of geometry 2 and the plate-shaped element 4.

[0061] A heat flow that passes through the main surfaces 21, 22 from the temperature-controlled element 3 or 4 into the sample material or from the sample material into the element 3 or 4 can be observed in arrangement 100 of the Fig. 1 The temperature of both temperature-controlled sides 11 and 12 of sample 1 is measured using heat flux transducers 5 and 6. Side 11 of sample 1 faces the temperature-controlled element 3, and side 12 faces the temperature-controlled element 4. The heat flux transducers 5 and 6 are designed to detect a heat flow passing through them. For example, the heat flux transducers 5 and 6 can provide an output signal proportional to the heat flow, from which an absolute numerical value for the heat flow can be obtained after calibration.

[0062] The heat flux sensors 5 and 6 are each planar and arranged in a central region of the associated main surface 21 or 22. An example schematic outline of the heat flux sensor 5 is shown in Figure 1. Fig. 2 indicated in a dotted line, the heat flux sensor 6 is arranged in the area of ​​the opposite main surface 22 analogously and symmetrically to the sensor 5.

[0063] Each of the heat flux sensors 5, 6 occupies a comparatively large central region of the main surface 21 or 22, which, for example, when viewed in the main surface 21 or 22, has a size of at least one-third of the dimension of the main surface 21 or 22 in each of the coordinate directions x and y. This helps to minimize the influence of edge effects and at the same time to detect the heat flux through a large area of ​​the sample material. For example, in Fig. 2 Each heat flux sensor 5, 6 incorporates a central area as an active measuring surface, which corresponds to approximately one quarter of the area of ​​the main surface 21 or 22. However, other, especially larger, area proportions are conceivable for further improving the averaging over the sample 1.

[0064] The arrangement 100 further comprises a heat sink 9, extending parallel to the temperature-controlled plate-shaped element 3, and a heat sink 10, extending parallel to the temperature-controlled plate-shaped element 4. The cooling of the heat sinks 9 and 10 is effected by means of a cooling system 50.

[0065] Furthermore, a temperature control system 7 or 8 is arranged between the heat sink 9 and the element 3, and between the heat sink 10 and the element 4, respectively, for temperature control. For example, the temperature control system 7, 8 can each be configured as a heating device, such as a resistance heater. With such a heating device, a temperature range that is advantageous in applications of the invention in the field of plastics recycling, and which can include temperatures of 200 degrees Celsius or more, can be effectively covered. In other applications of the invention where lower temperatures are used, the temperature control system 7, 8 can alternatively be configured as a Peltier system. A Peltier system offers the advantage of enabling both heating and cooling.

[0066] An assembly formed with the heat sink 9, the temperature control system 7, and the plate-shaped element 3 can be moved essentially perpendicular to a main plane of extension of the sample 1, and thus perpendicular to the main surfaces 21, 22, by means of traversing devices 30. A force F in the thickness direction D can be applied to the sample 1 by means of the devices 30. A travel distance or a thickness t of the sample 1 can be measured in the thickness direction D of the sample 1 by means of a thickness measuring device 40. In one variant, both elements 3 and 4, along with their respective associated heat sinks 9, 10 and temperature control systems 7, 8, can be moved relative to each other and relative to the sample 1.

[0067] The temperature control systems 7 and 8, the cooling system 50, the traversing devices 30, the thickness measuring device 40, and the heat flow sensors 5 and 6, as well as any additional temperature sensors, such as thermocouples, which may be provided in various combinations at the locations described in more detail below, are coupled to a data processing and control system 60. This system enables the control of the devices and systems 30, 50, 7, and 8, and the processing of measured values ​​acquired by the device 40, the heat flow sensors 5 and 6, and the aforementioned temperature sensors. The system 60 may also be coupled with input and output devices, memory, and other devices (not shown). It is also conceivable to connect the system 60 to a network interface.

[0068] Although in the exemplary embodiment of Fig. 1 If the main surfaces 21, 22 and thus the main extension planes of sample 1 and elements 3, 4 are oriented horizontally for example, a vertical orientation or any other orientation in space is also conceivable.

[0069] The following are methods according to exemplary embodiments of the invention, starting from a Fig. 7 The given schematic representation of the procedure is explained, and furthermore, exemplary results obtained with such methods, as well as results of conventional DSC measurements for comparison, are discussed.

[0070] Fig. 7 shows a method for identifying at least one component of the sample material with which sample 1 is formed.

[0071] In a first step S1 of the procedure, the sample 1 is prepared as described above, and the sample material is placed in a spatial region with the plate- or disk-like geometry 2, see Fig. 2 The sample material is arranged, for example, as a loose material, such as the granules mentioned above. Alternatively, in step S1, the sample material of sample 1 is formed with the plate- or disc-like geometry 2, for example, as a compact solid body or as a compressible body. The mass of sample 1 is greater than approximately 10 grams and is, for example, in the range between approximately 10 grams and approximately 10 kilograms, preferably between approximately 10 grams and approximately 1 kilogram, and more preferably between approximately 10 grams and approximately 200 grams. Another preferred mass of sample 1 is, for example, between approximately 10 grams and approximately 100 grams. Depending on the mass of sample 1, the dimensions of the arrangement 100 can be adapted accordingly, for example, with regard to the dimensions, the mechanical stability, and the heating and cooling capacities.

[0072] In a second step S2, the sample 1 is arranged between the two temperature-controlled, plate-shaped elements 3 and 4. This is done such that the temperature-controlled, plate-shaped elements 3 and 4 extend along one of the two opposing, essentially planar main surfaces 21 and 22 of the geometry 2. The sample 1 and the plate-shaped elements 3 and 4 are thus arranged parallel to each other in a substantially sandwich-like configuration. The planar heat flow sensor 5 is positioned between the main surface 21 and element 3, and the planar heat flow sensor 6 is positioned between the main surface 22 and element 4. The heat flow sensors 5 and 6 are preferably each fixedly integrated into the plate-shaped element 3 or 4 and are brought into contact with the main surfaces 21 and 22 after the sample 1 has been placed between the elements 3 and 4.

[0073] To prevent the test material from leaking out during subsequent heating and melting or liquefaction, or during a phase or glass transition, the test material of sample 1 is surrounded in exemplary embodiments with a coating 70 or a flexible sealing element 80, see Fig. 8 und 9 , in which the covering 70 or the sealing element 80, together with the elements 3, 4 still spaced apart from the sample 1, are shown for schematic illustration. The covering 70 or the sealing element 80 can alternatively be arranged in the arrangement 100 of the Fig. 1 The following are used to carry out the procedures of the embodiments described here: Fig. 1 However, it is not shown for the sake of clarity.

[0074] The covering 70 in Fig. 8 The casing 70 completely surrounds the sample material of sample 1 and encapsulates it in a closed volume. The casing 70 can be made of a flexible material. In contrast, the sealing element 80 surrounds the Fig. 9 the sample material of sample 1 is attached at the edge and frame-like along the circumference of sample 1, wherein the sealing element 80 can come into sealing contact with each of the temperature-controlled plate-shaped elements 3, 4.

[0075] In step S2, after arranging sample 1 between elements 3 and 4 in the manner just described, the following is done Fig. 1 The upper configuration, comprising the plate-shaped element 3, the associated temperature control system 7, and the heat sink 9, is moved towards the sample 1 by means of the traversing devices 30. This allows for defined contact with low, uniform thermal resistance at the main surfaces 21, 22 and, in the case of compressible and / or loose materials, a defined thickness t of the sample material. A defined setting and control of the thickness t is enabled by means of the thickness measuring device 40. Preferably, the traversing devices 30 are controlled by the data processing and control system 60, which is also connected to the measuring device 40 and records its measured distance or thickness values. This data is taken into account when controlling the traversing devices 30 and can also display and / or save these values ​​for documentation purposes.Using the traversing devices 30, a predefined force or load F can be applied to the specimen 1. The load F can be, for example, applied by means of a [missing information]. Fig. 1 The force is measured by the force measuring device (not shown) and compared with a target value. If the sealing element 80 is used, the procedure described above is carried out by means of the traversing devices 30 such that the sealing element 80 comes into contact with both elements 3 and 4 in a sealing manner.

[0076] In a third step S3a or S3b, a temperature change of the sample 1 is induced. For this purpose, a heat inflow Qz into the sample 1 or a heat outflow Qa from the sample 1 is symmetrically introduced through the two main surfaces 21 and 22 of the plate- or disk-like geometry 2. Due to the symmetrical operation of the arrangement 100, within the limits of the accuracy achievable with the components of the arrangement 100 and with sufficient homogeneity of the sample 1, essentially half of the total heat flow can flow in or out through one of the temperature-controlled, plate-shaped elements 3 and 4.

[0077] The temperature change of sample 1 is achieved by tempering the plate-shaped elements 3, 4 using the respective tempering systems 7, 8 and the respective cooling sinks 9, 10. For this purpose, the tempering systems 7, 8 and the cooling system 50 connected to the cooling sinks 9, 10 are controlled by the data processing and control system 60.

[0078] The temperature change induced in the third step S3a or S3b covers a temperature range within which at least one endothermic or exothermic change occurs in the at least one component of the test material. Such a change is preferably a phase transition, for example, melting or freezing of at least one or more components of the test material, or a glass transition of one or more such component(s), or both a phase transition and a glass transition, provided that one component, for example, has crystalline and amorphous components.

[0079] To bring about the temperature change, two different methods are provided according to alternative embodiments of the invention. This is in Fig. 7 This is illustrated by two alternative steps, S3a or S3b.

[0080] According to step S3a, the temperature change is carried out by subjecting the sample material to a predefined temperature profile, stored, for example, in a storage device (not shown) accessible to the data processing and control system 60. This temperature profile is continuous and, in particular, is selected as a predefined, linearly increasing or decreasing temperature ramp over time, covering the aforementioned temperature range. The temperature is measured, for example, by means of a temperature sensor(s) on one or both main surfaces 21, 22 of the sample 1, or the temperature is measured inside the sample 1. Alternatively or additionally, the temperature can be measured by means of a temperature sensor(s) on one or both main surfaces 21, 22.The temperature profile can be applied to the surface of the plate-shaped element 3 or 4, or both, or within one or both plate-shaped elements 3 and 4. The prescribed temperature profile can correspond to the temperature at one of these locations or to a temperature that can be modeled, for example, based on the temperature(s) at one or more of the aforementioned temperature measurement points. In step S3a, the temperature change is applied symmetrically to both sides 11 and 12 of the sample 1. With such symmetrical temperature control of the elements 3 and 4, and thus symmetrical operation and symmetrical induction of a temperature change in the sample 1, a difference in the heat flow supplied to or removed from the sample 1 via element 3 and element 4 can occur due to differing heat capacities or thermal conductivities of components of the sample material, if the sample 1 is highly inhomogeneous.

[0081] According to alternative step S3b, the temperature change of the sample is brought about by supplying or removing a constant heat flow from sample 1 over time. This is achieved symmetrically by tempering the temperature-controlled, plate-shaped elements 3 and 4, whereby the supplied or removed heat flow is controlled or preferably regulated to a predefined constant value by means of the data processing and control system 60. In particular, for symmetrical operation, the heat flow supplied or removed by both elements 3 and 4 is regulated to the same value in step S3b. For this purpose, the actual heat flow is measured using the heat flow sensors 5, 6.An additional measurement of the temperature of sample 1 at the main surfaces 21, 22 and / or in the interior of sample 1, as well as alternatively or additionally at surfaces of the plate-shaped elements 3, 4 and / or in their respective interiors, as described above for step S3a, is conceivable to improve the control of the heat flow.

[0082] During the temperature changes of sample 1 according to step S3a or S3b, adjustment can be made using the moving devices 30 so that, for example, during a phase or glass transition with liquefaction, good contact with sample 1 and good heat transfer to / from the plate-shaped elements 3 and 4 is maintained.

[0083] While the temperature change of sample 1 is carried out according to step S3a or S3b, a heat flow or temperature is simultaneously recorded in a fourth step S4a or alternatively S4b.

[0084] Specifically, in step S4a, while sample 1 is exposed to the defined, imprinted temperature profile, the heat flow into or out of sample 1 is detected by means of heat flow sensors 5, 6. From the detected heat flow values, a heat flow profile that can be represented as a curve is generated. Q̇ ( T ) or Q̇ ( t ) depending on a temperature T of the sample 1 or the temperature-controlled plate-shaped elements 3, 4, or instead depending on time t, receive.

[0085] Alternatively, in step S4b, while the defined, constant heat flow is applied to sample 1 and thus introduced into or removed from it, the temperature of sample 1 or of the temperature-controlled, plate-shaped elements 3, 4 is recorded. From the recorded temperature values, a curve representing the change in temperature over time is generated. dT / dt (t) or dT / dt (T) obtained depending on the temperature or depending on the time.

[0086] The temperature of sample 1 or of the plate-shaped elements 3, 4 can be recorded for step S4a, S4b at the locations described above for step S3a and S3b.

[0087] In a fifth step S5, the curve characteristics of the obtained profile, which can be represented as a curve, are either of the heat flow. Q̇ ( T ) or Q̇ ( t ) or the change in temperature over time dT / dt (t) or dT / dt (T) compared with a reference curve characteristic of a reference curve, preferably several or more preferably a plurality of reference curves.

[0088] This will be described in more detail below. The reference curves are investigated in advance for a wide variety of known sample materials using the same setup 100 and, in particular, under the same conditions and using the same temperature or heat flow program and the same measuring points as in the investigation of the actual sample 1, and the results are used as reference curves for Q̇ ( T ) or Q̇ ( t ) or dT / dt (t) or dT / dt (T) stored in advance in a database that the data processing and control system 60 can access.

[0089] The reference curves can be measured in advance and stored in the database for a known, uniform sample material or a known sample material mixture with two or more defined, known components, or for an expected, undesired component, such as a possible impurity.

[0090] The reference profiles available in the database preferably comprise at least a selection of pure substances and mixtures, such as plastics and plastic mixtures, adapted to the respective application. The database can be provided on a suitable storage medium (not shown in the figures) or accessed via a network from a remote storage medium.

[0091] Based on the result of the comparison, at least one component of the sample material, or several components of the sample material, are identified in the sixth step S6.

[0092] In Fig. 7 It is further indicated by the dashed line that steps S3a, S4a and S3b, S4b can be repeated. Thus, for example, it may be possible to perform several heating and / or cooling cycles using the temperature-controlled plate-shaped elements 3 and 4, repeatedly heating and cooling the sample material or at least one component in order to repeatedly melt or freeze the sample material or component(s) – in the case of a phase transition – or soften or solidify it – in the case of a glass transition. In this way, depending on the sample material or component(s), additional endothermic or exothermic changes, glass transitions, or phase transitions can be detected and used for identification during transformations in the material that occur due to temperature changes over time.For example, immediately after capturing the curve-representable course, step S5 of the comparison can be carried out, as exemplified in . Fig. 7 Alternatively, all planned heating / cooling processes can be executed first, the resulting curves saved, and then the comparison performed collectively in step S5. It can also be stipulated that not all heating / cooling curves are necessarily considered for the comparison, but rather a defined selection is provided. In particular, it can be advantageous to use the second heating cycle for the comparison, as this allows for a more uniform initial state.

[0093] The evaluation in step S5 is carried out by plotting the heat flow. Q̇ ( T ) above the temperature or Q̇ ( t) over time, or by plotting the temperature change dT / dt (t) over time or dT / dt (T) above the temperature.

[0094] In step S5, comparing the curve characteristics of the curve recorded for sample 1 and plotted in the manner described above with the reference curve characteristics includes, in particular, a comparison of the curve shapes of the curve plotted for sample 1 and the reference curve(s).

[0095] Transformations within the sample material manifest as steps or extrema in these curves. A comparison of the curve's characteristics and those of a reference curve can be performed using corresponding abscissa and / or ordinate values ​​that characterize at least segments of the curve's shape and the reference curve's shape. This can be achieved, for example, by determining onset, endset, and / or midpoint temperatures on the heat flow curve measured and plotted for sample 1. Q̇ ( t ) ,Q̇ ( T ) or the temperature change dT / dt ( t ), dT / dt ( TThe sample composition can be deduced from the characteristic temperatures (i.e., characteristic abscissa values, such as temperatures T at which extrema occur), as well as from integral areas under peaks. For this purpose, the characteristic temperatures (i.e., the onset, endset, midpoint, and extremal temperatures mentioned above), and, if applicable, the integral values ​​and / or the curve profiles in their entirety, are compared with the reference curves in the database and with corresponding characteristic temperatures previously determined for these reference curves. The ordinate values ​​assigned to the aforementioned characteristic abscissa values ​​can also be compared. The database contains reference curves for pure substances and mixtures relevant to the application.

[0096] During the evaluation in step S5, some embodiments of the method may, for example, further provide that for at least one stage of the obtained heat flow or temperature change profile, a stage height is determined and compared with a stage height of at least one of the reference curve(s). Similarly, an extremum value of the heat flow or temperature change curves can itself be directly compared as an ordinate value with an ordinate value of an extremum of the reference curve(s).

[0097] Furthermore, during the evaluation in step S5, a characteristic integral value in the sense of an area under at least one section of the curve for heat flow or time change of temperature, which was obtained for the investigation of sample 1, can be calculated and compared with integral values ​​of reference curves in order to further improve the evaluation.

[0098] Furthermore, embodiments are possible in which, in step S5, the obtained profile of the heat flow or the temporal change of the temperature is directly compared with the reference profile in their entirety. Here, the curve shape and the characteristics of the reference curve are preferably compared using a pattern recognition algorithm, for example, a machine learning algorithm, and / or an artificial intelligence method.

[0099] In some embodiments, step S5 may also include, if a material mixture is present in sample 1, "fitting" the result curve—in other words, the curve obtained for the heat flow or the time-dependent change in temperature, plotted against time or temperature, respectively—with several reference curves. This means fitting several reference curves to the actual measurement result and deducing the composition of the sample material in sample 1 from the resulting weights of the individual reference curves. For such a fitting, for example, a characteristic peak of each of the curves may be suitable, with the fitting then focusing, for example, on a curve segment containing such a peak.

[0100] Heat flow curves that represent an imprinted temperature change in the form of a linear ramp with the HFM-like arrangement 100 according to Fig. 1 according to embodiments of the invention and are therefore referred to as "HFM measurement", are in Fig. 3 for a polylactide (PLA) and in Fig. 5 The graph shows the curve shape for a paraffin, here using paraffin 6062 as an example. Some characteristic values, defining the shape of the curve in each section shown, are derived from the... Q̇ ( T The )-curve was derived in each case, are in the Fig. 3 , 5 specified.

[0101] It illustrates Fig. 3 For example, the "HFM measurement" shows a glass transition on PLA in the second heating as a stage at approximately 65 degrees Celsius, with a midpoint of the stage at 64.2 °C. Fig. 3 is the heat flow Q̇ The graph is plotted to illustrate, in particular, the shape of the curve and its characterization in an arbitrary unit (abbreviated as au). For comparison, it shows... Fig. 4 The result of a conventional DSC (differential scanning calorimetry) measurement for two heatings of the same polylactide, albeit on a significantly smaller sample mass. In the case of the Fig. 4 In the example shown, a midpoint of the glass transition stage of 65.8 °C is obtained during the first heating and 61.7 °C during the second heating, each using the conventional DSC method.

[0102] The comparison of the result obtained according to an embodiment of the invention in Fig. 3 for the second warm-up with the DSC results in Fig. 4 The first and second heating cycles generally show good similarity with regard to curve shape and numerical values. The method proposed by the invention thus makes it possible to obtain results similar to those obtained by DSC. Reference curves for known sample materials for building a database, as described above, for the identification and / or classification of the components of a sample material under investigation, are preferably generated using the HFM-like method of the invention, for example by means of arrangement 100, in order to achieve the best possible comparability.

[0103] In many cases, it can be advantageous to omit the second heating of the test material, such as for PLA, in the methods according to exemplary embodiments of the invention. Fig. 3 , to use, since the second heating process starts from a better defined initial state.

[0104] For the exemplary evaluation of the heat flow profile shown, carried out with a method according to an embodiment, which is subjected to a continuous temperature change in the form of a linear ramp with a slope of 1 Kelvin per minute by means of an arrangement 100 according to Fig. 1 The measurement taken for paraffin 6062 during initial heating is in Fig. 5 In addition to the abscissa and ordinate values ​​of two peaks and further temperature values ​​characterizing the curve shape, an integral value is shown hatched under a section of the obtained curve. Fig. 5 This shows a melting transition of paraffin 6062. It should be noted that in the case of paraffin 6062, the second heating yields very similar results. For comparison, in Fig. 6 This again shows the result of a conventional DSC measurement for the first heating of the same paraffin, which in turn shows the good agreement with the result obtained according to an embodiment of the invention in Fig. 5 , especially with regard to the shape of the curve.

[0105] For example, if the different paraffins 6062 and 5254 are examined according to a further embodiment and the measurement result is evaluated, their melting is shown as the occurrence of maxima in a temperature range between 50 °C and 70 °C.

[0106] The method, as described above with reference to exemplary embodiments, can be used, for example, to determine the purity of recycled plastic, such as granules produced from recycled plastic. According to the exemplary embodiments described above, the method offers a simple, time- and cost-saving, as well as accurate and reliable, way to determine whether and to what extent the granules contain admixtures or impurities, particularly other plastics, resulting from the recycling process. The exemplary embodiments described above, which symmetrically introduce heat into or remove it from the sample 1 with its plate- or disc-like geometry 2 via its main surfaces 21, 22, allow for the examination of batches on an industrially relevant scale, as in recycling processes, due to the relatively large sample weights that can be used.The effort required to examine the batch is manageable and practical.

[0107] The analysis of the batch by examining sample 1 can be used, for example, in the granulate manufacturing plant for quality control of the outgoing batch, or similarly at the customer's site, such as a plastics processor, for incoming goods inspection, and can yield reliable, accurate results. The sample material for sample 1 can be an already compounded plastic.

[0108] An advantage of the invention is that a measurement on a reference material or a blank measurement as a reference, simultaneously with the measurements on the actual object of investigation, i.e., sample 1, as is typically provided in the conventional DSC method by means of a second, empty crucible, is not necessary. The arrangement 100 of the Fig. 1The device used in the embodiments described here does not include any means for simultaneously performing a reference measurement. Nor is an empty "twin" of the arrangement 100 required as a reference for carrying out the methods according to the embodiments of the invention described here. The effort required to carry out the methods according to the embodiments described here is thus advantageously limited, both in terms of equipment and handling.

[0109] Depending on the application and the sample materials to be investigated, the arrangement 100 can be designed analogously to a generally known HFM apparatus, such as that described in ATSM C1784, and modified according to the temperatures at which the exothermic / endothermic processes to be observed in the sample material are expected. For example, an HFM apparatus can be modified to carry out the method described in the preceding embodiments for higher and / or lower temperatures and / or a wider temperature range that the apparatus is designed to accommodate and for which it is suitable, for example with regard to the power, design, or dimensioning of the heating and cooling devices 7, 8, 9, 10, any sealing materials, and possibly other components.For application in the field of plastics recycling, the arrangement 100 is thus designed in such a way that phase and / or glass transitions of the relevant, expected plastics as main and impurity components of the sample material are reliably detected from the temperature range that the arrangement 100 enables.

[0110] Although the invention has been fully described above with reference to preferred embodiments, it is not limited to these, but can be modified in many different ways. List of reference symbols

[0111] 1 Sample 2 Plate- or disc-like geometry 3, 4 Temperature-controlled plate-shaped element 5, 6 Heat flow sensor 7, 8 Temperature control system 9, 10 Heat sink 11 First side 12 Second side 21 First main surface 22 Second main surface 30 Traverse device 40 Thickness measuring device 50 Cooling system 60 Data processing and control system 70 Enclosure 80 Sealing element 100 Arrangement D Thickness direction F Load Qa Heat outflow Qz Heat inflow S1, S2 Step S3a, S3b Step S4a, S4b Step S5, S6 Step t Thickness x, y Coordinate direction

Claims

1. A method for identifying at least one component of a sample material, with which a sample (1) is formed, comprising: providing the sample (1), wherein the sample material is formed with a plate-like or disk-like geometry (2) or the sample material is arranged in a spatial region with a plate-like or disk-like geometry (2); arranging the sample (1) between two temperature-controllable plate-shaped elements (3, 4) in such a way that the temperature-controllable plate-shaped elements (3, 4) extend along a respective one of two opposite main surfaces (21, 22) of the plate-like or disk-like geometry (2); bringing about a temperature change of the sample (1) by bringing about a heat inflow (Qz) into the sample (1) or a heat outflow (Qa) out of the sample (1) in a symmetrical manner through the two main surfaces (21, 22) of the plate-like or disk-like geometry (2), wherein the temperature change is effected by controlling the temperature of the plate-shaped elements (3, 4) and covers a temperature range, within which at least one endothermic or exothermic change of the at least one component of the sample material occurs; detecting a heat flow flowing into the sample (1) or out of the sample (1) and obtaining from this a profile of the heat flow, which can be represented as curve, as a function of a temperature of the sample (1) or of the temperature-controllable plate-shaped elements (3, 4) or as a function of time, or detecting a temperature of the sample (1) or of the temperature-controllable plate-shaped elements (3, 4), and obtaining from this a profile of a temporal change of the temperature, which can be represented as curve, as a function of the temperature or as a function of time; comparing a curve state, in particular including a curve shape, of the obtained profile of the heat flow or of the temporal change of the temperature over temperature or time in each case to a reference curve state of one or several reference profiles; and identifying the at least one component of the sample material based on the result of the comparison.

2. The method according to claim 1, characterized in that the sample material is subjected to a continuous temperature profile, in particular a predefined temperature ramp, preferably a temperature ramp, which rises or falls linearly over time, when bringing about the temperature change of the sample (1).

3. The method according to claim 1, characterized in that the bringing about of the temperature change of the sample (1) takes place in such a way that a heat flow, which is constant over time, is supplied to the sample (1) or is removed from the sample (1).

4. The method according to one of the preceding claims, characterized in that the at least one component of the sample material runs through a phase transition and / or a glass transition within the temperature range covered during the temperature change.

5. The method according to one of the preceding claims, characterized in that the sample material is melted or frozen completely or partly during the temperature change.

6. The method according to one of the preceding claims, characterized in that the sample material is subjected to two or more temperature change processes, in particular to one or several heating processes and one or several cooling processes, by means of controlling the temperature of the temperature-controllable plate-shaped elements (3, 4).

7. The method according to one of the preceding claims, characterized in that a heat flow, which in each case flows from the temperature-controllable plate-shaped element (3, 4) into the sample (1) or vice versa, is in each case detected between the temperature-controllable plate-shaped element (3, 4) and the side (11, 12) of the sample (1) facing the temperature-controllable plate-shaped element (3, 4) in the region of the main surface (21, 22) of the plate-like or disk-like geometry (2), to which the temperature-controllable plate-shaped element (3, 4) is adjacent, in particular in each case by means of a heat flux transducer (5, 6), for example of a heat flux transducer (5, 6), which is formed in a planar manner.

8. The method according to claim 7, characterized in that the heat flux transducers (5, 6) are in each case arranged in a planar manner in a central region of one of the main surfaces (21, 22) of the plate-like or disk-like geometry (2) between the temperature-controllable plate-shaped element (3, 4) adjacent to this main surface (21, 22) and the sample (1).

9. The method according to one of the preceding claims, characterized in that one or both of the temperature-controllable plate-shaped elements (3, 4) is / are moved towards the sample (1) prior to bringing about the temperature change of the sample (1), wherein, conveyed via the temperature-controllable plate-shaped elements (3, 4), a predefined force is applied to the sample (1) in a thickness direction (D) of the plate-like or disk-like geometry (2) or a predefined thickness (t) of the sample (1) is adjusted in the thickness direction (D) of the plate-like or disk-like geometry (2).

10. The method according to one of the preceding claims, characterized in that the temperature of the sample (1) is detected on a surface of the sample or in an interior of the sample (1) and / or that the temperature of the temperature-controllable plate-shaped element (3, 4) is in each case detected on a surface thereof or in an interior thereof.

11. The method according to one of the preceding claims, characterized in that the comparing of the curve state and of the reference curve state is carried out by using corresponding abscissa and / or ordinate values, which in each case characterize the curve shape and the reference curve shape at least in sections.

12. The method according to one of the preceding claims, characterized in that the comparing of the curve state and of the reference curve state is carried out by means of at least one characteristic level and / or of at least one characteristic extremum, in particular peak, in each case of the obtained profile of the heat flow or of the temporal change of the temperature as well as of the reference profile, wherein the level or the extremum in each case corresponds in particular to a conversion within the sample material.

13. The method according to one of the preceding claims, characterized in that at least one abscissa value, which corresponds to an onset point or endpoint or midpoint or turning point or extreme value assigned to the level or the extremum within the curve shape, is determined for at least one level or at least one extremum, in particular a peak, of the obtained profile of the heat flow or the temporal change of the temperature, and is compared to at least one corresponding abscissa value of at least one reference profile.

14. The method according to one of the preceding claims, characterized in that a height of the level is determined for at least one level of the obtained profile of the heat flow or of the temporal change of the temperature, and is compared to at least one height of at least one level of at least one reference profile, and / or that the assigned extreme value of the heat flow or of the temporal change of the temperature is determined for at least one extremum, in particular a peak, of the obtained profile of the heat flow or of the temporal change of the temperature, and is compared to an extreme value of at least one extremum, in particular peak, of at least one refence profile.

15. The method according to one of the preceding claims, characterized in that at least one characteristic integral value, in particular a surface below at least one section of the obtained profile of the heat flow represented as curve or of the temporal change of the temperature, for example under a peak, is determined and compared to a characteristic integral value of the reference profile and that the identification of the at least one component of the sample material is additionally carried out based on the result of the comparison of the characteristic integral values.

16. The method according to one of the preceding claims, characterized in that the obtained profile of the heat flow or of the temporal change of the temperature is compared directly to the reference profile in each case in the totality thereof.

17. The method according to one of the preceding claims, characterized in that the comparing of the curve state, in particular curve shape, and of the reference curve state, in particular reference curve shape, includes the use of a pattern recognition algorithm, for example of an adaptive algorithm and / or of an artificial intelligence method.

18. The method according to one of the preceding claims, characterized in that a plurality of profiles of the heat flow or of the temporal change of the temperature, which are in each case determined beforehand for a known sample material or sample material mixture, are used as reference profiles.

19. The method according to one of the preceding claims, characterized in that the reference profiles are provided in the form of a data collection, which includes reference profiles of an application-specific selection of pure substances and mixtures, for example plastics and plastic mixtures.

20. The method according to one of the preceding claims, characterized in that the sample material is provided as a loose material with a plurality of individual pieces, for example as a granulate or a powder or that the sample material is provided as a cohesive body.

21. The method according to one of the preceding claims, characterized in that the detection of the profile of the heat flow or of the temperature takes place in the absence of a simultaneous reference measurement, in particular on a reference, which geometrically corresponds to the sample (1) and which is formed with a material known beforehand, or by means of empty measurement as reference, within the same analysis arrangement (100) or by means of a further identical analysis arrangement (100).

22. The method according to one of the preceding claims, characterized in that the analyzed sample (1) has a mass of more than approximately 10 grams, for example between approximately 10 grams and approximately 10 kilograms, preferably between approximately 10 grams and approximately 1 kilogram, more preferably between approximately 10 grams and approximately 200 grams, for example between approximately 10 grams and approximately 100 grams.

23. The method according to one of the preceding claims, characterized in that the sample material is a mixture and that a material or several materials, which is / are contained in the sample (1), is / are identified by means of the method.

24. The method according to one of the preceding claims, characterized in that the method is used for determining the purity of a plastics recyclate, in particular for identifying possible admixtures or contaminations and / or for determining an extent thereof.

25. The method according to one of the preceding claims, characterized in that the method is used in a process chain during the plastics recycling.

26. The method according to one of the preceding claims, characterized in that a compounded substance mixture, in particular a compounded plastic, is provided as the sample material of the sample (1).