Method for identifying at least one kind of constituent in sample material

Abstract

To provide an efficient and highly reliable method capable of analyzing a sufficiently large amount of sample for representatively characterizing a material batch as much as possible.SOLUTION: A sample is arranged between two plate-like elements 3, 4 capable of controlling temperature so as to extend along each one of two main surfaces 21, 22 opposite to each other in a plate-like or disc-like geometry 2. A temperature change in the sample is generated when a heat inflow Qz or a heat outflow Qa is symmetrically provided for the sample through the two main surfaces. The detected heat inflow Qz or heat outflow Qa is obtained as a profile of a heat flow that can be represented as a curved line as a function of a temperature or a function of a time of the sample or the plate-like element. A curved line state of the profile obtained in terms of a temporal change in the heat flow or temperature is compared with a reference curved line state. At least one kind of constituent is identified on the basis of a comparison result.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for identifying at least one component in a sample material. [Background technology]

[0002] Although the present invention is useful for identifying components in a wide variety of sample materials and can be used in a wide variety of fields, the present invention and the set of problems underlying it will be described in more detail and illustratively below using plastic recycling as an example (although the present invention is not limited to plastic recycling applications).

[0003] In the field of plastics recycling, the composition of recycled plastic materials, e.g., plastic granules, is often determined at different stages of the recycling process with the aim of receiving information on the purity of the material and the degree of potential mixtures. It is necessary to detect the proportion of undesired polymer types that may be present in the analyzed material, especially in recycled materials.

[0004] The most widespread methods in the field of plastics recycling are aimed at the sorting of starting materials, and include IR spectroscopy, the use of cameras in conjunction with image recognition, further optical methods, or separation according to material density. However, these conventional methods do not cover the entire range of relevant plastics. Thus, for example, IR spectroscopy is not sensitive to black plastics. In particular, the above-mentioned methods also present significant difficulties when it comes to the analysis of the components of complex substance mixtures, for example for quality control purposes.

[0005] For example, it is known to determine the melting or glass transition temperatures of plastics by so-called differential scanning calorimetry (DSC for short). In this case, it is possible to conclude the type of analyzed plastic based on the peaks of the measurement variables obtained by the DSC method. Heat flow differential scanning calorimetry generally allows the recognition of many plastics and offers high sensitivity.

[0006] However, in the plastics recycling industry, large amounts of material are processed and must be tested for purity and composition. However, material samples traditionally analyzed by differential scanning calorimetry and the instruments used for this purpose are extremely small, in the milligram range. Therefore, DSC analysis of individual samples from a large batch of material, for example from a silo filled with plastic granules, does not provide a reliable, representative image of the entire batch. Analyzing multiple samples from a batch with DSC to refine the information is extremely complex and time-consuming.

[0007] Non-Patent Document 1 (G. Matuschek et al., "Simultaneous thermal analysis of large samples," Journal of Thermal Analysis, Vol. 47 (1996), pp. 623 ff.) describes an apparatus for performing STA (simultaneous thermal analysis) on larger weight samples. However, for use in the recycling industry, the acquisition of this equipment is relatively expensive and its application is relatively complicated. Furthermore, sample distribution may be unfavorable. For use in the recycling industry, a more cost-effective and easier-to-handle approach is desirable.

[0008] Furthermore, devices called HFM instruments are known, where HFM stands for "heat flow meter" in English. The thermal conductivity of a sample is usually measured using such devices, for example to determine the thermal insulation properties of an insulating jacket. For this purpose, the sample is placed between two temperature-controllable plates in the HFM device, with the help of which a temperature gradient is applied to the sample, and in the steady state when thermal equilibrium is reached, the heat flow through the sample is measured and the thermal conductivity is measured numerically.

[0009] Similarly, it is known to measure the specific heat capacity Cp of, for example, polymers or insulating materials with an HFM device. For this purpose, both plates are first held at the same temperature, then subjected to a short temperature ramp, and then returned to isothermal conditions. The integral of the heat flow is then evaluated.

[0010] Additionally, industry standard ASTM C1784 describes the operating mode of the HFM, where both plates are at the same temperature and a stepped isothermal temperature program is used to determine the heat storage capacity of the sample in terms of sensible and latent heat.

[0011] Patent document 1 (WO 2022 / 250533) describes a differential scanning calorimetry method and apparatus for determining the thermodynamic properties and composition of materials. In the approach described in Patent document 1, a plate-shaped sample is heated or cooled on one side. On the opposite side of the sample, multiple temperature sensors are arranged in a planar grid pattern.

[0012] In light of the above, it would be desirable, for example in the field of plastics recycling, to be able to accurately characterize larger batches of material in a simple, easy to handle, time- and cost-effective manner to gain an accurate understanding of their composition and potential contaminants. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] International Publication No. 2022 / 250533 Brochure [Non-patent literature]

[0014] [Non-Patent Document 1] G. Matuschek et al., "Simultaneous thermal analysis of large samples," Journal of Thermal Analysis, Vol. 47 (1996), pp. 623ff. Summary of the Invention [Problem to be solved by the invention]

[0015] The object of the present invention is therefore to propose an efficient and reliable method that allows the analysis of sufficiently large sample amounts in order to characterize a material batch as representatively as possible. The method of the present invention is particularly suitable and advantageously functional for the accurate characterization of material batches on an industrial scale by taking and analyzing samples. [Means for solving the problem]

[0016] According to the invention, this problem is solved by a method having the features of claim 1.

[0017] According to this, a method for identifying at least one component in a sample material forming a sample is proposed, the method comprising: - a step in which a sample is prepared, the sample material being formed by a plate-like or disc-like geometry or the sample material being arranged in a spatial region having a plate-like or disc-like geometry; - the sample is placed between two temperature-controllable plate-like elements, the temperature-controllable plate-like elements extending along each of two opposing main surfaces in a plate- or disk-like geometry; - a temperature change of the sample is caused by symmetrically inducing heat inflow into or outflow from the sample via the two main surfaces in a plate-like or disk-like geometry, the temperature change being caused by a temperature-controlled plate-like element, the temperature change covering a temperature range in which at least one endothermic or exothermic change occurs in at least one component of the sample material; the heat flow into or out of the sample is detected, from which a profile of the heat flow is obtained which can be represented as a curve as a function of the temperature of the sample or of the temperature-controllable plate-like element or as a function of time; Or, - detecting the temperature of the sample or of the temperature-controllable plate-like element and obtaining from it a profile of the temporal change of the temperature, which can be represented as a curve as a function of temperature or as a function of time; - the curve condition, including in particular the curve shape, of the profile obtained for the temperature or the temporal variation of the temperature over time or the heat flow is compared with the reference curve conditions of one or more reference profiles; - at least one component in the sample material is identified based on the comparison result; Includes.

[0018] The idea behind the present invention is to analyze a sample material essentially based on the method of differential scanning calorimetry (DSC), but with a much larger amount of material than DSC, so that the heterogeneous composition of the material to be analyzed, e.g. recycled material, can be represented by the sample in a much improved manner and the components of the mixture can be accurately identified.

[0019] For this purpose, in the present invention, an HFM device can be used similarly to a DSC. In this case, the HFM device can correspond to or be configured similarly to the device described in, for example, the industrial standard ASTM C1784 and the references cited therein. However, depending on the sample material to be analyzed, the HFM device can be modified, for example, with respect to the temperature range it can cover. Therefore, if the HFM device provides a wider temperature range and a higher maximum temperature through a modified temperature control unit, it may be advantageously applied to the plastic recycling field.

[0020] Advantageously, the method of the invention provides, in relation to the plate- or disk-like geometry of the sample material or of the area on which it is placed, a substantially symmetrical heat introduction or removal via the two main surfaces, in other words a symmetrical heat flow or temperature change on the sample, which reduces heat loss to the outside and allows a well-defined temperature gradient and, at least to a very good approximation, a one-dimensional heat flow, which advantageously contributes not only to accurate and reliable measurement results but also to a reliable identification of the components.

[0021] The plate- or disk-like geometry of the sample material has the further advantage that endothermic / exothermic processes in the sample material, e.g., melting or glass transition of its components, induced by the supply or removal of heat, occur rapidly, and therefore no significant temperature gradients within the sample and therefore no "melting front" is created. This is achieved by the large heat input surface provided in the geometry provided, despite the relatively large sample weight.

[0022] The present invention further advantageously allows for the identification of components without the need for simultaneous measurement of a reference material or a simultaneous blank measurement as a reference, which contributes to a reduction in equipment and associated costs, as well as to a simplification of the implementation of the method. In this way, the identification of components is not only reliable, but also time-saving and easily achievable, which is therefore advantageous on an industrial scale, for example for use in the field of plastics recycling or other processes.

[0023] Advantageous designs and further configurations of the invention are set out in the dependent claims and the description, with reference to the drawings.

[0024] In one design, in effecting a temperature change in the sample, the sample material is exposed to a continuous temperature profile, particularly a predetermined temperature ramp, preferably a temperature ramp that increases or decreases linearly over time.

[0025] In a further configuration, causing a temperature change in the sample is performed such that a time-constant heat flow is supplied to or removed from the sample.

[0026] According to one design, at least one component in the sample material undergoes a phase transition and / or glass transition within the temperature range covered during the temperature change, and such temperature-dependent changes in the components in the sample material can be effectively used to identify one or more components.

[0027] In a further configuration, the sample material completely or partially melts or solidifies during the temperature change, and the melting or solidification, as a phase transition between solid and liquid, is similarly useful for characterizing the components of the sample material.

[0028] In particular, the temperature-controllable plate-like element is used to heat and / or cool the sample.

[0029] In one design, the sample material is subjected to two or more temperature change processes, in particular one or more heating processes and one or more cooling processes, by controlling the temperature of a temperature-controllable plate-shaped element. This can be used to better identify components. Depending on the sample material or its components, temperature-dependent processes of the sample material can be influenced by defined heating and / or cooling rates. In particular, the second heating and its evaluation can be used to establish a uniform initial state, for example, by preceding melting, and to make an evaluation based on such a defined initial state. In particular, the second heating and subsequent further cooling step, in which, for example, crystallization can be observed, can be important and can be used to compare the curve state with a reference curve state. Such a cooling step can, for example, make it possible to draw conclusions regarding additives that may be included in the sample as crystallization promoters.

[0030] In one design, the heat flow from the temperature-controllable plate-shaped element into the sample or vice versa is detected by a heat flow meter, for example a planar heat flow meter, between the temperature-controllable plate-shaped element and the side of the sample facing the temperature-controllable plate-shaped element in the main surface area of the plate- or disk-shaped geometry to which the temperature-controllable plate-shaped elements are adjacent. This allows reliable, accurate and direct detection of the heat flow. The double-sided detection of the heat flow can also be used, for example, to control the symmetry of the operating mode.

[0031] In one design, the heat flow meters are each positioned between the sample and the temperature-controllable plate-like element adjacent to one of the major surfaces in a plate-like or disk-like geometry in a central region of the major surface. In particular, each heat flow meter can occupy a large central region of the major surface. In some exemplary designs, the central region of the major surface occupied by the heat flow meter can have a size of at least one-third or at least half of the dimensions of the major surface in each of two, particularly orthogonal, coordinate directions, as viewed from the major surface. In some exemplary designs, the central region occupied by the heat flow meter as the measurement surface can particularly occupy at least one-ninth, at least one-sixth, or at least one-quarter of the surface area of the major surface. This makes it possible to make the influence of boundary effects, which are difficult to completely avoid due to the finite size of the sample and the temperature-controllable plate-like element, negligible or non-existent. The planar extent of the heat flow meter in the large central region described above allows for inclusion of a large portion of the sample material, enabling useful information about the sample to be obtained. Further increasing the proportion of the major surface that the heat flow meter occupies as the active measurement surface beyond the values mentioned above is advantageous to achieve further averaging over a sample that may be inhomogeneous.

[0032] In a further configuration, before bringing about a temperature change of the sample, one or both of the temperature-controllable plate-like elements are moved towards the sample, and a predetermined force is applied to the sample via the temperature-controllable plate-like element in the thickness direction of the plate- or disk-like geometry, or a predetermined thickness of the sample is adjusted in the thickness direction of the plate- or disk-like geometry, thereby making it possible to set predetermined conditions, such as a predetermined thickness of the sample, for the analysis to be performed, to realize a reliable contact with the sample material for a predetermined temperature control, and to guarantee a heat transfer resistance that is as small and uniform as possible at the contact surface.

[0033] In one design, it is particularly envisaged that the sample material is provided with a casing that encloses the sample material in a closed volume. Alternatively, in another design, it is particularly envisaged that the sample material is circumferentially surrounded on the edge side of the sample by a flexible sealing element that extends in the thickness direction of the sample substantially over the thickness or fill height of the sample and that, together with the temperature-controllable plate-shaped element, encloses the closed sample volume. In this case, the sealing element is particularly configured to be in sealing contact with the temperature-controllable plate-shaped element. The casing or sealing element is provided as a kind of edge, which makes it possible to prevent the escape of sample material that liquefies during melting. Due to its flexibility, the sealing element also preferably allows tracing by moving the plate-shaped element in order to maintain contact between the sample material and the plate-shaped element during melting.

[0034] According to one design, it is envisaged that the temperature of the sample is detected on the surface of the sample or inside the sample and / or the temperature of the temperature-controllable plate-shaped elements is detected on the surface of these temperature-controllable plate-shaped elements or inside the temperature-controllable plate-shaped elements.

[0035] In a further configuration, the comparison of the curve state with the reference curve state is performed by using corresponding abscissa and / or ordinate values that at least partially characterize the curve shape and the reference curve shape.

[0036] In another further configuration, the comparison of the curve state with the reference curve state is carried out by means of a profile obtained for the heat flow profile or for the temperature change over time, and at least one characteristic level and / or at least one characteristic extremum, in particular a peak, in the reference profile, respectively, the level or extremum corresponding in particular to a transformation in the sample material.

[0037] In one design, at least one abscissa value corresponding to a start point or end point or intermediate point or turning point or extreme value assigned to a level or extreme value in the curve shape is determined for at least one level or at least extreme value, in particular a peak, obtained for the time variation of the heat flow or temperature and compared with the corresponding abscissa value in at least one reference profile.

[0038] According to a further design, a height of a level is determined for at least one level in the acquired profile of the temporal variation of the heat flow or temperature and compared with at least one height of at least one level in the at least one reference profile, and / or an extremum assigned to the temporal variation of the heat flow or temperature is determined for at least one extremum, in particular a peak, in the acquired profile of the temporal variation of the heat flow or temperature and compared with at least one extremum, in particular a peak extremum, in the at least one reference profile.

[0039] The above descriptions and further configurations, which can be combined for further improvements, allow components to be reliably identified.

[0040] In a further embodiment, at least one characteristic integral, in particular the surface under at least one section, for example, under a peak, in the acquired profile of the time variation of heat flow or temperature represented as a curve, is determined and compared with the characteristic integral of a reference profile. In this further embodiment, identification of at least one component in the sample material is additionally performed based on the comparison of the characteristic integrals. This can contribute to further improvement of the identification. The integral can correspond to an enthalpy difference, for example, in the case of a phase transition in the sample, or a difference in specific heat capacity, for example, in the case of a glass transition in the sample.

[0041] In a further design, the acquired profile of the heat flow or temperature change over time is directly compared in its entirety with a reference profile.

[0042] In a further configuration, the comparison of the curve state, in particular the curve shape, with the reference curve state, in particular the reference curve shape, comprises the use of a pattern recognition algorithm, for example an adaptive algorithm and / or an artificial intelligence method.

[0043] Direct comparison and / or use of pattern recognition or artificial intelligence can further improve the accuracy and reliability of the identification.

[0044] According to one design, a number of predetermined profiles of heat flow or temperature over time for a known sample material or mixture of sample materials are used as reference profiles.

[0045] According to one design, the reference profiles are provided in the form of a data set that includes selected reference profiles specific to applications of pure substances and mixtures, such as plastics and plastic mixtures.

[0046] The availability of multiple reference profiles based on a collection of data, which may be provided, for example, in the form of a database, makes it possible to provide reliable information about a wide range of potential contaminants or contaminations in a sample. Such a method may be extremely useful, for example, for the control of recycling processes, where complete certainty about the starting materials is rarely possible.

[0047] The collection of data, eg a database, may be provided, for example, on a suitable storage medium or may be accessible via a network.

[0048] In a further configuration, the sample material is provided as a bulk material having a plurality of individual pieces, for example as granules or powder.

[0049] In another further configuration, the sample material is provided as an aggregate.

[0050] Providing it as a bulk material or solid allows for the use of a variety of sample types.

[0051] According to one design, the detection of the heat flow or temperature profile is performed without a simultaneous reference measurement, in particular a reference measurement that corresponds geometrically to the sample and is made of a known material, or without a blank reference measurement within the same analytical device or using an identical additional analytical device. This significantly reduces the amount of equipment and handling costs during sample analysis, contributing to cost and time savings. For example, a blank "twin" as a reference in the analytical device is not required. Therefore, a tailored and simplified analysis of the sample material is possible, while avoiding possible sources of error.

[0052] In one design, the sample to be analyzed has a mass of more than about 10 grams, e.g., from about 10 grams to about 10 kilograms, preferably from about 10 grams to about 1 kilogram, more preferably from about 10 grams to about 200 grams, e.g., from about 10 grams to about 100 grams. Such samples can provide reliable and representative information for larger batches of material, such as those found on an industrial scale in the recycling sector.

[0053] According to a further aspect, it is envisaged that the sample material is a mixture and that one or more materials contained in the sample are to be identified by the method.

[0054] In an advantageous design, the method is used to determine the purity of plastic recycled materials, in particular to identify and / or determine the extent of potential adulteration or contamination.

[0055] The method is used in the process chain during plastics recycling, thus allowing not only time-saving and simplified control of the recycling process at different stages, but also quality control of the end products obtained, e.g., recycled plastic granules.

[0056] In a further exemplary embodiment, a complex substance mixture, in particular a complex plastic, is provided as sample material for the sample. The present invention also advantageously makes it possible to analyze plastics that have already been processed in this way with respect to their components.

[0057] The invention will now be explained in more detail with reference to exemplary embodiments shown in the accompanying drawings.

[0058] The accompanying drawings are included in and are a part of this specification to provide a further understanding of the invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Many of the other embodiments and advantages of the invention can be readily appreciated as the same becomes better understood by reference to the following detailed description. Elements of the drawings are not necessarily drawn to scale relative to each other. Like reference numerals represent like parts. [Brief explanation of the drawings]

[0059] [Figure 1] 1 is a schematic cross-sectional view of an apparatus used to carry out a method according to an exemplary embodiment of the present invention; [Figure 2] A schematic perspective view showing the plate- or disk-shaped shape of a sample material used to perform a method according to an exemplary embodiment, or the plate- or disk-shaped shape of a spatial region into which a sample material is placed to perform a method according to an exemplary embodiment. [Figure 3] 2 is a graph illustrating exemplary measurement results obtained by the apparatus shown generally in FIG. 1 and used to identify at least one component in a sample material, for example, measured on a sample of polylactic acid (PLA), according to an exemplary embodiment. [Figure 4] 1 is a graph showing exemplary measurement results for polylactic acid (PLA) obtained by conventional methods of differential scanning calorimetry (DSC), where two heating cycles are exemplarily shown. [Figure 5]2 is a graph showing exemplary measurement results obtained by the apparatus shown schematically in FIG. 1 and used to identify at least one component in a sample material, for example, measured on a sample of paraffin, according to a further exemplary embodiment. [Figure 6] 1 is a graph showing exemplary measurement results of paraffin obtained by conventional methods of differential scanning calorimetry (DSC). [Figure 7] 1 is a schematic flow chart of a method according to an exemplary embodiment of the present invention; [Figure 8] 1 is a schematic diagram illustrating an exemplary casing for sample material for carrying out a method according to an exemplary embodiment of the present invention. [Figure 9] 10 is a schematic diagram showing an edge-side sealing element surrounding a sample material for carrying out a method according to a further exemplary embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0060] Unless otherwise stated, the same reference numbers in the drawings refer to the same or functionally similar components. All directional terms, such as "top," "bottom," "left," "right," "superior," "lower," "horizontal," "vertical," "rear," "front," and similar terms, are used for descriptive purposes only and do not limit the embodiments shown in the drawings to any particular orientation.

[0061] FIG. 1 shows an apparatus 100 that can be used to carry out a method according to an exemplary embodiment of the present invention, which will be described below. The apparatus 100 is used for analyzing a sample 1. To provide the sample 1, a sample material, for example taken from a batch of loose plastic granules obtained in a recycling process, is arranged in a spatial region having a plate- or disk-shaped geometry 2. For this purpose, the sample material can be packed into a sample frame (not shown in detail) that defines the geometry 2. Alternatively, the sample material sample 1 can be a coherent solid or alternatively a compressible body (e.g., individually adjusted) having a plate- or disk-shaped geometry 2. FIG. 2 shows a schematic representation of this type of plate- or disk-shaped geometry 2. In FIG. 2, the geometry 2 is formed in the shape of a flat, rectangular parallelepiped, and the extension of the geometry 2 in two mutually orthogonal coordinate directions x and y is significantly greater than the extension or thickness t of the geometry 2 in a thickness direction D orthogonal to x and y. The main surfaces 21, 22 of the geometry 2 are of substantially the same shape and size, are parallel and are, for example, rectangular in the exemplary embodiment shown in FIG.

[0062] The sample material of sample 1, regardless of its physical form, such as granules or agglomerates, is in particular a mixture comprising at least one main material, which may be mixed with one or more other materials, in particular as contaminants of the main material that is desired to be as pure as possible due to the recycling process involved. Thus, the sample material comprises one or more components, the term referring not only to the main component but also to undesired contaminants.

[0063] 1, the sample 1 is sandwiched between two temperature-controllable plate-like elements 3, 4. The apparatus 100 further comprises a heat flow meter (heat flux converter) 5 arranged between a main surface 21 of the geometry 2 and the plate-like element 3, and a heat flow meter (heat flux converter) 6 arranged between a main surface 22 of the geometry 2 and the plate-like element 4.

[0064] 1, heat flow from the temperature-controllable elements 3, 4 through the major surfaces 21, 22 into the sample material, or from the sample material into the elements 3, 4, can be measured by heat flow meters 5, 6 on both temperature-controlled sides 11, 12 of the sample 1. Side 11 of the sample 1 faces the temperature-controllable element 3, and side 12 faces the temperature-controllable element 4. The heat flow meters 5, 6 are configured to detect the heat flow passing through them. For example, the heat flow meters 5, 6 can provide output signals proportional to the heat flow passing therethrough, from which, after calibration, the absolute value of the heat flow can be obtained.

[0065] The heat flow meters 5 and 6 are each formed in a planar shape and are arranged in the central regions of the assigned main surfaces 21 and 22. The contour of the heat flow meter 5 is exemplarily and schematically shown by dotted lines in Figure 2, and the heat flow meter 6 is arranged similarly and symmetrically to the heat flow meter 5 in the region of the opposite main surface 22.

[0066] The heat flow meters 5 and 6 each occupy a relatively large central area of the major surfaces 21 and 22, e.g., this central area, when viewed relative to the major surfaces 21 and 22, has a size that is at least one-third of the dimensions of the major surfaces 21 and 22 in each of the coordinate directions x and y. This minimizes boundary effects while simultaneously detecting heat flow through a large area of the sample material. In FIG. 2, for example, each heat flow meter 5 and 6 occupies a central area as its active measurement surface that corresponds to approximately one-quarter of the surface area of the major surfaces 21 and 22. However, other, particularly larger, surface areas are also conceivable to further improve averaging of the sample 1.

[0067] The device 100 further comprises a heat sink 9 assigned to the temperature-controllable plate-shaped element 3 and running parallel to it, and a heat sink 10 assigned to the temperature-controllable plate-shaped element 4 and running parallel to it. Cooling of the heat sinks 9, 10 themselves is provided by a cooling system 50.

[0068] Furthermore, temperature control systems 7 and 8 for temperature control are arranged between the heat sink 9 and the element 3 and between the heat sink 10 and the element 4, respectively. The temperature control systems 7 and 8 can be configured as or together with heating units, such as resistive heating units. This type of heating unit can be advantageous, for example, when applying the invention in the field of plastic recycling, where a temperature range that can include temperatures of, for example, 200°C or higher can be well covered. If lower temperatures are used in other applications of the invention, the temperature control systems 7 and 8 can alternatively be configured as Peltier systems. Peltier systems can offer the advantage of not only heating but also cooling.

[0069] The assembly formed by the heat sink 9, the temperature control system 7 and the plate-like element 3 can further be displaced substantially perpendicular to the main extension plane of the sample 1, and thus perpendicular to the main surfaces 21, 22, by means of a displacement unit 30. The unit 30 allows a force F to be applied to the sample 1 in a thickness direction D. The displacement path or the thickness t of the sample 1 can be detected in the thickness direction D of the sample 1 by a thickness measurement unit 40. In one variant, both elements 3, 4, in addition to the heat sinks 9, 10 and temperature control systems 7, 8 assigned to them, can be displaced up and down each other and towards the sample 1.

[0070] The temperature control systems 7, 8, the cooling system 50, the displacement unit 30, the thickness measurement unit 40, the heat flow meters 5, 6, and optional additional temperature sensors, such as thermocouples, which may be provided in different combinations as will be explained in more detail below, are coupled to a data processing and control system 60, which in particular controls the units and systems 30, 50, 7, 8 and processes the measurements detected by the unit 40, the heat flow meters 5, 6, and the above-mentioned temperature sensors. The system 60 may additionally be coupled to input and output units (not shown), storage (not shown), and further units. It is further conceivable to couple the system 60 to a network interface.

[0071] In the exemplary embodiment shown in FIG. 1, the main surfaces 21, 22, and therefore the main extension planes of the sample and elements 3, 4, are illustratively aligned horizontally, but vertical alignment or any other alignment in space is equally conceivable.

[0072] Below, a method according to an exemplary embodiment of the present invention will be described based on the process sequence schematic diagram shown in FIG. 7 , and exemplary results obtained by such a method will also be described, as well as results of conventional DSC measurements for comparison.

[0073] FIG. 7 illustrates a method for identifying at least one component in the sample material forming sample 1.

[0074] In the first step S1 of the method, a sample 1 is provided as described above, where the sample material is arranged as a loose material, such as granules, in a spatial region having a plate- or disk-shaped geometry 2 (see FIG. 2 ). Alternatively, the sample material of the sample 1 is formed in the plate- or disk-shaped geometry 2 in step S1, for example, as a compressed solid or compressible body. The mass of the sample 1 is greater than about 10 grams, for example, in the range of about 10 grams to about 10 kilograms, preferably about 10 grams to about 1 kilogram, and more preferably about 10 grams to about 200 grams. A more preferred mass of the sample 1 is, for example, in the range of about 10 grams to about 100 grams. Depending on the mass of the sample 1, the dimensions of the corresponding device 100 can be adapted, for example, with respect to dimensions, mechanical stability, and heating and cooling capacity.

[0075] In a second step S2, the sample 1 is placed between two temperature-controllable plate-like elements 3, 4. This arrangement is performed so that the temperature-controllable plate-like elements 3, 4 extend along each of two substantially flat main surfaces 21, 22 facing each other in the geometry 2. The sample 1 and the plate-like elements 3, 4 are therefore arranged parallel to each other in a substantially sandwich-like manner. In this case, a planar heat flow sensor 5 is arranged between the main surface 21 and the element 3, and a planar heat flow sensor 6 is arranged between the main surface 22 and the element 4. The heat flow sensors 5, 6 are preferably fixedly integrated into the plate-like elements 3, 4, respectively, and come into contact with the main surfaces 21, 22 after the sample 1 has been placed between the elements 3, 4.

[0076] To prevent the sample material from leaking upon subsequent heating and melting or liquefaction during phase or glass transition, the sample material of the sample is enclosed in a casing 70 or flexible sealing element 80 in exemplary embodiments (see FIGS. 8 and 9), where the casing 70 or sealing element 80 is shown schematically with elements 3 and 4 still spaced apart from the sample 1. The casing 70 or sealing element 80 can alternatively be used in the apparatus 100 of FIG. 1 to perform the exemplary embodiment methods described herein, but is not shown in FIG. 1 for clarity.

[0077] The casing 70 shown in Fig. 8 completely surrounds the sample material of the sample 1, enclosing it in a closed volume. The casing 70 can be made of a flexible material. In contrast, the sealing element 80 shown in Fig. 9 surrounds the sample material of the sample 1 at the edge of the sample 1 in a frame-like manner along the circumference of the sample 1, and in this case the sealing element 80 can come into contact with the temperature-controllable plate-like elements 3 and 4 to form a seal.

[0078] In step S2, after the sample 1 has been placed between the elements 3 and 4 in the manner described above, the upper arrangement shown in FIG. 1, including the plate-like element 3, the temperature control system 7 assigned to the plate-like element 3, and the heat sink 9, is moved toward the sample 1 by the displacement unit 30. This allows for uniform and defined contact with the main surfaces 21 and 22 with low heat transfer resistance and, in the case of compressible and / or bulk materials, a defined thickness t of the sample material. Defined adjustment and control of the thickness t is possible by the thickness measurement unit 40. The displacement unit 30 is preferably controlled by a data processing and control system 60, which is additionally connected to the measurement unit 40 and can record the detected distance or thickness values, take these values into account when controlling the displacement unit 30, and save them for display and / or documentation. In this case, a defined force or load F can be applied to the sample 1 by the displacement unit 30. The load F can be detected by a force measurement unit (not shown in FIG. 1) and adjusted to a desired value. If a sealing element 80 is used, the method described above is carried out such that the displacement unit 30 causes the sealing element 80 to abut against both elements 3, 4 to form a seal.

[0079] In a third step S3a or S3b, a temperature change is effected on the sample 1. For this purpose, a heat inflow Qz into the sample 1 or a heat outflow Qa from the sample 1 is effected symmetrically via the two main surfaces 21, 22 of the plate- or disk-shaped geometry 2. Due to the symmetrical operating mode of the device 100, taking into account the precision achievable with the components of the device 100 and a sufficient homogeneity of the sample 1, substantially half of the total heat flow can flow in or out via one of the temperature-controllable plate-shaped elements 3, 4.

[0080] The temperature change of the sample 1 is carried out by temperature control of the plate-like elements 3 and 4 with the help of the provided temperature control systems 7 and 8 and the provided heat sinks 9 and 10. For this purpose, the data processing and control system 60 controls a cooling system 50 connected to the temperature control systems 7 and 8 and the heat sinks 9 and 10.

[0081] The temperature change occurring in the third step S3a, S3b covers a temperature range in which at least one endothermic or exothermic change of at least one component in the sample material occurs, such a change being preferably a phase transition, for example a melting or solidification of at least one component or components in the sample material, or a glass transition of one or more such components, or a phase transition and a glass transition, if one component has, for example, a proportion of crystalline and amorphous parts.

[0082] According to alternative exemplary embodiments of the present invention, two different methods are provided for effecting the temperature change, which is evidenced in Figure 7 by the two alternative steps S3a or S3b.

[0083] According to step S3a, a temperature change is performed so that the sample material is exposed to a predetermined temperature profile, for example, stored in a memory unit (not shown) accessible to the data processing and control system 60. This temperature profile is continuously selected, in particular as a predetermined temperature ramp, linearly increasing or decreasing over time and covering the aforementioned temperature range. In this case, the temperature is detected, for example, by a temperature sensor or sensors at one or both main surfaces 21, 22 of the sample 1 or inside the sample 1. Alternatively or additionally, a temperature sensor can detect the temperature on the surface of the plate-like element 3 facing the main surfaces 21, 22, or on the surface of the plate-like element 4, or on both surfaces of the plate-like elements, or inside one or both of the plate-like elements 3, 4. The specified temperature profile can correspond to the temperature at one of these locations or can correspond to a temperature that can be modeled, for example, based on the temperatures of one or more of the aforementioned temperature measurement points. In step S3a, the temperature change is applied symmetrically to both sides 11, 12 of the sample. If the temperature control in elements 3 and 4 is symmetrical in this way, and therefore the operating modes and temperature changes in sample 1 occur symmetrically, the differences in the heat flow supplied or removed, respectively, through elements 3 and 4 may be due to different heat capacities or thermal conductivities of the components of the sample material, and may be different if the inhomogeneity of sample 1 is significant.

[0084] According to an alternative step S3b, the temperature change of the sample is brought about by supplying or removing a constant heat flow to or from the sample 1 over time. This is realized symmetrically by temperature-controlling the temperature-controllable plate-like elements 3, 4, in which case the input or removed heat flow is controlled, preferably regulated, to a predetermined constant value by the data processing and control system 60. In particular, the heat flows supplied or removed by the two elements 3, 4 are regulated to the same value for symmetrical operation in step S3b. For this purpose, the actually present heat flow is measured with the aid of heat flow meters 5, 6. To improve the control of the heat flow, additional measurements of the temperature at the main surfaces 21, 22 of the sample 1 and / or in the interior of the sample 1, as described above with respect to step S3a, and alternatively or additionally, additional measurements of the temperature at the surfaces of the plate-like elements 3, 4 and / or in the interior of the sample 1, are conceivable.

[0085] During the temperature change of the sample 1 according to step S3a or S3b, readjustment can be carried out by the displacement unit 30, thereby maintaining good contact with the sample 1 and good heat conduction to and from the plate-like elements 3, 4, for example when a phase transition with liquefaction or a glass transition occurs.

[0086] While the temperature of the sample 1 is being changed according to step S3a or S3b, in a fourth step S4a or alternatively step S4b, the heat flow or temperature is simultaneously detected.

[0087] Specifically, in step S4a, the sample 1 is exposed to a predetermined temperature profile, while the heat flow into or out of the sample 1 is detected by the heat flow meters 5 and 6. The heat flow can be represented as a curve. JPEG2025116828000002.jpg56 or The profile JPEG2025116828000003.jpg55 is obtained from the detected heat flow values as a function of the temperature T of the sample 1 or the temperature T of the temperature-controllable plate-like elements 3, 4 or as a function of time t.

[0088] Alternatively, in step S4b, the temperature of the sample 1 or the temperature-controllable plate-like element 3, 4 is detected while a predetermined and constant heat flow is applied to the sample 1 and thus introduced into or removed from the sample 1. The profile of the change in temperature over time can be represented as a curve. JPEG2025116828000004.jpg511 or JPEG2025116828000005.jpg512 is obtained from the detected temperature values as a function of temperature or as a function of time.

[0089] In steps S4a, S4b the temperature of the sample 1 or plate-like elements 3, 4 can be detected as described above for steps S3a, S3b.

[0090] In a fifth step S5, the curve state of the obtained profile, which can be represented as a curve, i.e., the heat flow JPEG2025116828000006.jpg56 or JPEG2025116828000007.jpg55 curve state or temperature change over time JPEG2025116828000008.jpg511 or The curve state of JPEG2025116828000009.jpg512 is preferably compared to the reference curve state of several reference curves, or more preferably to a plurality of reference curve states.

[0091] This will be explained in more detail below. The reference curves are previously analyzed for a variety of known sample materials by the same apparatus 100, in particular under the same conditions and at the same heat flow program temperatures and at the same measurement points as during the analysis of the actual sample 1, and the results are stored in a database accessible to the data processing and control system 60. JPEG2025116828000010.jpg56 or JPEG2025116828000011.jpg55 or JPEG2025116828000012.jpg511 or It is stored in advance as the reference curve for JPEG2025116828000013.jpg512.

[0092] In this case, the reference curve can be measured in advance for a known homogeneous sample material, or a known sample material mixture having two or more known components, or for expected undesired components, such as contaminants, and can be stored in a database.

[0093] The reference profiles available in the database preferably include at least one option for pure substances and mixtures, e.g., plastics and plastic mixtures, and are adapted to the respective application. The database can be provided on a suitable storage medium (not shown) or can be accessible from a remote storage medium via a network.

[0094] Based on the comparison result, in a sixth step S6, at least one component in the sample material is identified, or multiple components in the sample material are identified.

[0095] FIG. 7 further indicates with dashed lines that steps S3a, S4a, or S3b, S4b, respectively, can be repeated. Thus, for example, several heating and / or cooling processes can be performed by the temperature-controllable plate-like elements 3, 4, repeatedly heating and cooling the sample material or at least one component, respectively, thereby repeatedly melting or solidifying the sample material or one or more components in the case of a phase transition, or softening or solidifying the sample material or one or more components in the case of a glass transition. This allows for the detection of additional endothermic or exothermic changes, glass transitions, or phase transitions, in the case of material transformations caused by temperature changes over time, which can be used to identify the sample material or its components. In this case, for example, comparison step S5 can be performed immediately after detecting a profile that can be represented as a curve, as exemplarily shown in FIG. 7 . Alternatively, all of the provided heating / cooling processes can be performed first, and the obtained curve profiles can be stored and then compared together in step S5. Furthermore, it is not necessary for all profiles obtained for the heating / cooling processes to be considered for comparison; it is also conceivable that a defined option is provided. In particular, it is advantageous to use the second heating for comparison, since this heating allows the assumption of a uniform initial state.

[0096] The evaluation in step S5 is performed by calculating the heat flow rate relative to the temperature. JPEG2025116828000014.jpg56 or time By applying JPEG2025116828000015.jpg55, or temperature change over time JPEG2025116828000016.jpg511 or temperature This is done by applying JPEG2025116828000017.jpg512.

[0097] In step S5, comparing the curve state of the curve detected for sample 1 and applied as described above with the reference curve state also includes, in particular, comparing the curve shape of the curve applied for sample 1 with the curve shape of the reference curve.

[0098] Transformations in the sample material are represented by levels or extrema in these curve profiles. Comparison of the curve state with the reference curve state can be performed using corresponding abscissa and / or ordinate values, which at least partially characterize the curve shape and the reference curve shape. For example, heat flow JPEG2025116828000018.jpg55, JPEG2025116828000019.jpg56 or temperature change JPEG2025116828000020.jpg511, In addition to determining the start, end, and / or midpoint temperatures of the curve measured and applied to sample 1 for each of the abscissa values, e.g., the temperatures at which the extrema occur, the sample composition can be determined, for example, based on the integral surface under the peak. For this purpose, in particular, the characteristic temperatures are compared as characteristic abscissa values, in particular the above-mentioned start, end, midpoint, and extrema temperatures, but also, where appropriate, the integral values and / or the entire curve profile, with reference curves in a database and corresponding characteristic temperatures previously determined for these reference curves. The ordinate values assigned to the above-mentioned characteristic abscissa values can also be compared. The database contains reference curves for pure substances and mixtures relevant to the application.

[0099] As part of the evaluation in step S5, for example, in the case of some exemplary embodiments of the method, it is further conceivable that the height of at least one level of the obtained profile of the heat flow or temperature change over time is determined and compared with the height of at least one level of the reference curve. Likewise, for example, the extrema of the heat flow or temperature change over time curve itself can be used as ordinate values and directly compared with the ordinate values of the extrema of the reference curve.

[0100] A characteristic integral value for the surface under at least one section of the curve relating to the change in heat flow or temperature over time obtained for analyzing sample 1 can be additionally calculated during the evaluation in step S5 and compared with the integral value of the reference curve in order to further improve the evaluation.

[0101] In step S5, further exemplary embodiments are also conceivable in which the obtained profile of the heat flow or temperature over time is directly compared in its entirety with a reference profile, whereby the curve shape and the reference curve state are preferably compared with each other by using pattern recognition algorithms, for example adaptive algorithms and / or artificial intelligence methods.

[0102] In some exemplary embodiments of step 5S, if a material mixture is present in sample 1, it is further possible to "fit" the result curve, i.e. the curve obtained for the temporal change of heat flow or temperature, respectively, to several reference curves, i.e. to fit several reference curves to the actual measurement results, and to conclude the composition of the sample material of sample 1 from the weighted results obtained for the individual reference curves. For example, in such a fitting, characteristic peaks of each curve can be assumed, and in this case, the fitting is focused, for example, on the curve section having such peaks.

[0103] Heat flow curves obtained for temperature changes applied in the form of linear ramps using an HFM-like apparatus 100 according to an exemplary embodiment of the present invention, and therefore referred to as "HFM measurements," are shown in Figure 3 for polylactic acid (PLA) and in Figure 5 for paraffin, in this case, for example, paraffin 6062. Some characteristic values that distinguish the shape of the curves in each section shown are: JPEG2025116828000022.jpg56 curve and is shown in Figures 3 and 5.

[0104] FIG. 3 shows, for example, that the glass transition of PLA occurs during the second heating "HFM measurement" at a level of about 65° C., with the midpoint of that level being 64.2° C. In FIG. JPEG2025116828000023.jpg52 is expressed in arbitrary units (abbreviated as au) to specifically illustrate the curve shape and its characterization. In comparison, Figure 4 shows the results of a conventional DSC measurement (differential scanning calorimetry) for two heatings of the same polylactic acid, but with a significantly smaller sample mass. In the example shown in Figure 4, the conventional DSC method obtains a midpoint of 65.8 °C, corresponding to the glass transition, during the first heating, and a level of 61.7 °C during the second heating.

[0105] A comparison of the results obtained for the second heating according to an exemplary embodiment of the present invention in Figure 3 with the DSC results obtained for the first and second heating in Figure 4 shows a generally good similarity in terms of curve shape and numerical values. Thus, it is possible to obtain DSC-like results with the method proposed in the present invention. For the identification and / or classification of the components of the sample material to be analyzed, as described above, reference curves of known sample materials for building a database are preferably generated with the HFM-like method of the present invention, e.g., by the device 100, in order to achieve the best possible comparability.

[0106] In many cases, it may be advantageous to use a second heating of the sample material, such as the PLA shown in Figure 3, in a method according to an exemplary embodiment of the present invention, since the second heating assumes a better defined initial state.

[0107] In the heat flow profile evaluation shown exemplarily in FIG. 5 and performed by a method according to an exemplary embodiment, this heat flow profile was measured for paraffin 6062 during a first heating run using apparatus 100 in FIG. 1 at a continuous temperature change in the form of a linear ramp with a gradient of 1 Kelvin per minute. In FIG. 5, the integral under the resulting curve section is represented by a diagonal line, in addition to the abscissa and ordinate values of the two peaks and additional temperature values characterizing the curve shape. FIG. 5 shows the melting transition of paraffin 6062. It should be noted that for paraffin 6062, very similar results are obtained in the second heating run. In comparison, the results of a conventional DSC measurement of the same paraffin for the first heating run are shown in FIG. 6 and are in good agreement with the results in FIG. 5 obtained according to an exemplary embodiment of the present invention, particularly with regard to the curve shape.

[0108] For example, when analyzing different paraffins 6062 and 5254 according to yet another exemplary embodiment and evaluating the measurements, their melting occurs as a maximum in the temperature range between 50°C and 70°C.

[0109] Methods according to the above-described exemplary embodiments can be used, for example, to measure the purity of plastic recycled materials, e.g., granules made from recycled plastics. The methods according to the above-described exemplary embodiments provide a simple, time- and cost-saving, as well as accurate and reliable, option for determining whether and to what extent granules contain contaminants or impurities from the recycling process, particularly other plastics. The above-described exemplary embodiments, in which heat is symmetrically introduced to or removed from the sample 1 through the major surfaces 21, 22 of the plate-like or disk-like geometry 2, allow for the use of relatively large sample weights of sample material, enabling the analysis of batches on an industrially significant scale, such as during a recycling process. The effort required to analyze a batch is manageable and feasible.

[0110] The analysis of batches by analyzing Sample 1 can be easily, quickly and efficiently used, for example, in granule manufacturing processes for quality control of outgoing batches, or similarly in incoming inspections at customers, for example plastics processors, and can provide reliable and accurate results. The sample material of Sample 1 can also be an already compounded plastic.

[0111] The present invention has the advantage that it is not necessary to measure a reference material or a blank reference measurement simultaneously with the measurement of the actual analyte, i.e., sample 1. This is typically done, for example, in conventional DSC methods, by using a second empty crucible. The apparatus 100 shown in FIG. 1 , as used in the exemplary embodiments described herein, does not include a unit for simultaneously performing a reference measurement. A blank reference "twin" of the apparatus 100 is also not required to perform the method according to the exemplary embodiments described herein. In this way, the effort required to perform the method according to the exemplary embodiments described herein is advantageously limited, not only in terms of the apparatus but also in terms of handling.

[0112] Depending on the application and sample material being analyzed, the device 100 can be configured similarly to commonly known HFM devices, such as those described in ATSM C 1784, and can be modified according to the temperature at which the observed exothermic / endothermic processes are expected in the sample material. In this case, for example, an HFM device for implementing the method described in the exemplary embodiment above can be modified for higher and / or lower temperatures and / or a wider temperature range that the device allows and is suitable for, for example, with respect to the performance, layout, or dimensions of the heating and cooling units 7, 8, 9, 10, and possibly sealing materials, as well as other components. When applied to the field of plastic recycling, the device 100 can be configured to ensure that the phase and / or glass transitions of plastics, which are expected to be major and contaminant components of the sample material, are captured by the temperature range achieved by the device 100.

[0113] While the present invention has been fully described above based on preferred and exemplary embodiments, the present invention is not limited thereto and can be variously modified. [Explanation of symbols]

[0114] 1. Sample 2 Plate or disc geometry 3,4 Temperature-controllable plate-like element 5,6 Heat flow meter (heat flux converter) 7,8 Temperature control system 9,10 Heat sink 11 First aspect 12 Second aspect 21 1st main surface 22 Second main surface 30 Displacement Unit 40 Thickness measurement unit 50 Cooling System 60 Data Processing and Control Systems 70 Casing 80 sealing elements 100 devices D thickness direction F load Qa Heat outflow Qz heat inflow S1, S2 steps Steps S3a and S3b Steps S4a and S4b S5, S6 steps t thickness x,y coordinate direction

Claims

1. 1. A method for identifying at least one component in a sample material forming a sample (1), comprising: - preparing the sample (1), wherein the sample material is formed by a plate-like or disk-like geometry (2) or the sample material is arranged in a spatial region having a plate-like or disk-like geometry (2); placing the sample (1) between two temperature-controllable plate-like elements (3, 4) such that the temperature-controllable plate-like elements (3, 4) extend along each of two opposing main surfaces (21, 22) of the plate- or disk-like geometry (2); - a step of inducing a temperature change in the sample (1) by inducing a heat inflow (Qz) into the sample (1) or a heat outflow (Qa) symmetrically from the sample (1) via the two main surfaces (21, 22) of the plate- or disk-shaped geometry (2), the temperature change being caused by temperature control of the plate-shaped elements (3, 4), the temperature change covering a temperature range in which at least one endothermic or exothermic change occurs in at least one component of the sample material; detecting the heat flow into or out of the sample (1) and obtaining a profile of the heat flow therefrom, which can be represented as a curve as a function of the temperature of the sample (1) or of the temperature-controllable plate-like element (3, 4) or as a function of time; Or, detecting the temperature of the sample (1) or of the temperature-controllable plate-like element (3, 4) and obtaining therefrom a profile of the temporal variation of said temperature, which can be represented as a curve as a function of temperature or as a function of time; - comparing the curve condition, in particular the curve shape, of the profile obtained for the temperature or the temporal variation of the temperature or the heat flow with respect to time with reference curve conditions of one or more reference profiles; identifying the at least one component in the sample material based on a result of the comparison; A method comprising:

2. 2. The method according to claim 1, characterized in that when bringing about the temperature change of the sample (1), the sample material is exposed to a continuous temperature profile, in particular a predetermined temperature ramp, preferably a temperature ramp that increases or decreases linearly over time.

3. 2. The method of claim 1, wherein the temperature change of the sample (1) is effected by supplying or removing a constant heat flow to or from the sample (1) over time.

4. 4. The method according to claim 1, wherein at least one component in the sample material undergoes a phase transition and / or a glass transition within the temperature range covered during the temperature change.

5. 5. The method according to any one of claims 1 to 4, characterized in that the sample material melts or solidifies completely or partially during the temperature change.

6. 6. The method according to any one of claims 1 to 5, characterized in that the sample material is subjected to two or more temperature change processes, in particular one or more heating processes and one or more cooling processes, by temperature control of the temperature-controllable plate-shaped elements (3, 4).

7. 7. The method according to claim 1, characterized in that the heat flow from the temperature-controllable plate-shaped element (3, 4) into the sample (1) or vice versa from the sample (1) to the temperature-controllable plate-shaped element (3, 4) is detected between the temperature-controllable plate-shaped element (3, 4) and a side surface (11, 12) of the sample facing the temperature-controllable plate-shaped element (3, 4) in the region of the main surface (21, 22) of the plate- or disk-shaped geometry (2) to which the temperature-controllable plate-shaped element (3, 4) adjoins, in particular by means of a heat flow meter (5, 6), for example a planar heat flow meter (5, 6).

8. 8. The method according to claim 7, characterized in that the heat flow meters (5, 6) are arranged in the central region of one of the main surfaces (21, 22) of the plate- or disk-shaped geometry (2), respectively, between the temperature-controllable plate-shaped element (3, 4) adjacent to the main surface (21, 22) and the sample (1).

9. 9. The method according to claim 1, characterized in that, before bringing about the temperature change of the sample (1), one or both of the temperature-controllable plate-shaped elements (3, 4) are moved towards the sample (1) and a predetermined force is applied to the sample (1) via the temperature-controllable plate-shaped elements (3, 4) in the thickness direction (D) of the plate- or disk-shaped geometry (2) or a predetermined thickness (t) of the sample (1) is adjusted in the thickness direction (D) of the plate- or disk-shaped geometry (2).

10. 10. The method according to claim 1, wherein the temperature of the sample (1) is detected on the surface of the sample or inside the sample (1) and / or the temperature of the temperature-controllable plate-shaped element (3, 4) is detected on the surface of the temperature-controllable plate-shaped element (3, 4) or inside the temperature-controllable plate-shaped element (3, 4).

11. 11. The method according to claim 1, wherein the comparison of the curve state with the reference curve state is performed by using corresponding abscissa and / or ordinate values that at least partially characterize the curve shape and the reference curve shape.

12. 12. The method according to claim 1, wherein the comparison of the curve state with the reference curve state is carried out by means of at least one characteristic level and / or at least one characteristic extremum, in particular a peak, in the profile obtained for the profile of the heat flow or for the time variation of the temperature and in the reference profile, respectively, wherein the level or the extremum corresponds in particular to a transformation in the sample material.

13. 13. The method according to claim 1, characterized in that at least one abscissa value corresponding to a start point or an end point or an intermediate point or a turning point or an extremum assigned to said level or said extremum in said curve shape is determined for said at least one level or at least extremum, in particular a peak, obtained for said time variation of said heat flow or said temperature, and compared with a corresponding abscissa value in at least one reference profile.

14. 14. The method according to claim 1, characterized in that a height of the level is determined for at least one level in the acquired profile of the variation of the heat flow or the temperature over time and compared with at least one height of at least one level in at least one reference profile, and / or an extremum assigned to the variation of the heat flow or the temperature over time is determined for at least one extremum, in particular a peak, in the acquired profile of the variation of the heat flow or the temperature over time and compared with at least one extremum, in particular a peak, in at least one reference profile.

15. 15. The method according to claim 1, further comprising determining at least one characteristic integral, in particular the surface under at least one section, e.g. under a peak, in the acquired profile of the time variation of the heat flow or the temperature represented as a curve, and comparing it with characteristic integrals of the reference profile, and additionally identifying the at least one component in the sample material based on the comparison of the characteristic integrals.

16. 16. The method according to any one of claims 1 to 15, characterized in that the obtained profile of the temporal variation of the heat flow or the temperature is directly compared in its entirety with the reference profile.

17. 17. The method according to any one of claims 1 to 16, characterized in that the comparison of the curve state, in particular curve shape, with the reference curve state, in particular reference curve shape, comprises the use of a pattern recognition algorithm, such as an adaptive algorithm and / or an artificial intelligence method.

18. 18. The method according to any one of claims 1 to 17, characterized in that a plurality of profiles of the heat flow or temperature over time determined in advance for known sample materials or sample material mixtures are used as reference profiles.

19. 19. The method according to any one of claims 1 to 18, characterized in that the reference profiles are provided in the form of a data collection, the data collection comprising selected reference profiles specific to applications of pure substances and mixtures, such as plastics and plastic mixtures.

20. 20. The method of any one of claims 1 to 19, wherein the sample material is provided as a bulk material having a plurality of individual pieces, for example as granules or powder, or as an agglomerate.

21. 21. The method according to claim 1, wherein the detection of the profile of the heat flow or the temperature is performed without a simultaneous reference measurement, in particular a reference measurement that corresponds geometrically to the sample (1) and is made of a known material, or a blank measurement as a reference is performed within the same analytical device (100) or without using a further identical analytical device (100).

22. 22. The method according to any one of claims 1 to 21, characterized in that the sample (1) to be analyzed has a mass of more than about 10 grams, for example between about 10 grams and about 10 kilograms, preferably between about 10 grams and about 1 kilogram, more preferably between about 10 grams and about 200 grams, for example between about 10 grams and about 100 grams.

23. 23. The method according to any one of claims 1 to 22, characterized in that the sample material is a mixture and the method identifies one or more materials contained in the sample (1).

24. 24. The method according to any one of claims 1 to 23, characterized in that the method is used to determine the purity of recycled plastic materials, in particular to identify and / or determine the extent of potential mixtures or contaminants.

25. 25. The method according to any one of claims 1 to 24, characterized in that it is used in a process chain during the recycling of plastics.

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

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