Method for identifying at least one component in a 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 Art

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

[0003] In the field of plastic recycling, at different stages of the recycling process, it is often the aim to determine the composition of recycled plastic materials, such as plastic granules, and to receive information regarding the purity of the material and the degree of potential mixtures. It is necessary to detect the proportion of the types of undesired polymers that may be present in the material to be analyzed, particularly recycled materials.

[0004] Methods widely used in the field of plastic recycling rather intend a starting material sorting process, and examples include IR spectroscopy, the use of cameras related to image recognition, further optical methods, or separation according to the density of the material. However, these conventional methods cannot cover the entire relevant field of plastics. Thus, for example, IR spectroscopy is not sensitive to black plastics. In particular, when performing component analysis of a composite material mixture for the purpose of, for example, quality control, the above-described methods are extremely difficult.

[0005] For example, the melting temperature or glass transition temperature of plastics is known to be determined by so-called differential scanning calorimetry (DSC). In this case, it is possible to conclude the type of plastic being analyzed based on the peaks of the measured variables obtained by the DSC method. Thermal flow differential scanning calorimetry can generally recognize many plastics and provides high sensitivity.

[0006] However, in the plastic recycling industry, large quantities of material must be processed and its purity and composition inspected. However, material samples analyzed conventionally using differential scanning calorimetry (DSC) and the equipment used for this purpose are extremely small, in the milligram range. Therefore, analyzing individual samples from large material batches, such as silos filled with plastic granules, using DSC does not provide a reliable representative image of the entire batch. Improving the information by analyzing multiple samples from a batch using DSC 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), pages 623 et seq.) describes an apparatus for performing simultaneous thermal analysis (STA) on larger samples. However, for use in the recycling industry, acquiring this equipment is relatively expensive, and its application is relatively complex. Furthermore, it may result in unfavorable sample distribution. For use in the recycling industry, a more cost-effective and easier-to-handle approach is desirable.

[0008] Furthermore, there is a device known as an HFM instrument, where HFM stands for "heat flow meter." The thermal conductivity of a sample is typically measured using such a device, 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 instrument, and a temperature gradient is applied to the sample with the help of these plates. In a steady state where thermal equilibrium is reached, the heat flow through the sample is measured, and the thermal conductivity is numerically measured.

[0009] Similarly, HFM (Heat Microwave Field) devices are known to measure the specific heat capacity Cp of materials such as polymers and insulating materials. For this purpose, both plates are first held at the same temperature, then exposed to a short temperature ramp (temperature gradient), and then placed back under isothermal conditions. This allows for the evaluation of the integral of the heat flow.

[0010] Furthermore, the industrial standard ASTM C1784 describes the operating mode of HFM, in which both plates are brought to the same temperature, and a stepwise 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 (International Publication No. 2022 / 250533) describes a differential scanning calorimetry method and a differential scanning calorimetry apparatus, and describes the determination of the thermodynamic properties and composition of a material. In the approach described in Patent Document 1, one side of a plate-shaped sample is heated or cooled. On the opposite side of the sample, a plurality of temperature sensors are provided, arranged planarly in a grid pattern.

[0012] Based on the above, it is desirable, for example, in the field of plastic recycling, to be able to accurately characterize larger batches of material in a simple, easy-to-handle, time-efficient, and cost-effective manner, and 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] See the paper "Simultaneous thermal analysis of large samples" by G. Matuschek et al., Journal of Thermal Analysis, Vol. 47 (1996), pages 623 et seq. [Overview of the Initiative] [Problems that the invention aims to solve]

[0015] Therefore, the object of the present invention is to propose an efficient and reliable method that can analyze a sufficiently large sample volume in order to characterize a material batch as representatively as possible. The method of the present invention is particularly suitable for accurately characterizing material batches on an industrial scale by sampling and analyzing the sample, and is also functional. [Means for solving the problem]

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

[0017] According to this, a method is proposed for identifying at least one component in the sample material forming the sample, and this method is - A step in which a sample is prepared, wherein the sample material is formed by a plate-like or disk-like geometry, or the sample material is placed in a spatial region having a plate-like or disk-like geometry, - The sample is arranged between two temperature-controllable plate-like elements such that these temperature-controllable plate-like elements extend along one of each of two opposing main surfaces in a plate-like or disk-like geometry, - A step in which a temperature change is brought about in a sample by heat inflow into or out of the sample symmetrically through two main surfaces in a plate-like or disk-like geometry, wherein this temperature change is caused by temperature control of the plate-like element, and the temperature change covers a temperature range in which at least one endothermic or exothermic change occurs in at least one component of the sample material, - Heat flow entering or leaving the sample is detected, and a heat flow profile is obtained from this, which can be expressed as a curve, either as a function of temperature of the sample or a temperature-controllable plate-like element, or as a function of time. Or, The steps include detecting the temperature of a sample or a temperature-controllable plate-like element, and obtaining a profile of the temporal change in temperature that can be expressed as a curve, either as a function of temperature or as a function of time, - A step in which the curve state of a profile obtained with respect to temperature or the temporal change of temperature or heat flow, particularly including the curve shape, is compared with the reference curve state of one or more reference profiles, - The step of identifying at least one component in the sample material based on the comparison results, Includes.

[0018] The underlying concept of this invention is to analyze sample materials based on differential scanning calorimetry (DSC), but with the aim of analyzing samples containing a much larger quantity of material than would be possible with DSC. This allows for a significantly improved and more representative representation of the heterogeneous composition of the material to be analyzed, such as recycled materials, and enables accurate identification of the components of a mixture.

[0019] For this purpose, in the present invention, the HFM device can be used in the same manner as the DSC. In this case, the HFM device can be made to correspond to, for example, the devices described in the industrial standard ASTM C1784 and the references cited therein, or can be formed in a similar manner. However, depending on the sample material to be analyzed, the HFM device can be modified, for example, with respect to the coverable temperature range. Therefore, if the HFM device provides a wider temperature range and a higher maximum temperature by means of a modified temperature control unit, it can be advantageous for an advantageous application in the field of plastic recycling.

[0020] Advantageously, according to the method of the present invention, with respect to the plate-like or disc-like geometry of the sample material or the region where the sample material is disposed, the introduction or removal of heat through two main surfaces is substantially symmetric, in other words, by symmetrically loading the sample with a heat flux or symmetrically applying a temperature change, external heat loss can be reduced and a clearly defined temperature gradient and at least a substantially one-dimensional heat flux in a very good approximation can be achieved. This contributes advantageously not only to accurate and reliable measurement results but also to reliable identification with respect to the components.

[0021] In the plate-like or disc-like geometry of the sample material, the endothermic process / exothermic process of the sample material induced by the supply or removal of heat, for example, the melting or glass transition of its components, occurs rapidly, and thus no significant temperature gradient occurs within the sample, and thus no "melting surface" occurs either. This is achieved by providing a large heat input surface in the provided geometry despite the relatively large weight of the sample.

[0022] In the present invention, further, the identification of components can be advantageously achieved without the need for simultaneous measurement of reference materials or simultaneous spatio-temporal measurement as a reference. This contributes to the reduction of equipment and equipment-related costs, as well as the simplification of method implementation. Thus, the identification of components is not only highly reliable, but also time-saving and easily achievable, and is therefore advantageous on an industrial scale, for example, in the field of plastic recycling or in other processes.

[0023] Advantageous designs and further configurations of the present invention are as described in the dependent claims and the main text of the specification in reference to the drawings.

[0024] In one design, when bringing about 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 rises or falls linearly with time.

[0025] In a further configuration, bringing about a temperature change in the sample is done such that a heat flux that is constant over time 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 a glass transition within the temperature range covered during the temperature change. Such a temperature-induced change 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 melts or solidifies completely or partially during the temperature change. 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, a 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-changing processes, particularly one or more heating processes and one or more cooling processes, by temperature control of a temperature-controllable plate-like element. This can be used to better identify components. Depending on the sample material or its components, the temperature-dependent processes of the sample material can be influenced by specified heating and / or cooling rates. In particular, a second heating and its evaluation can be used, for example, to establish a uniform initial state by preceding melting, and to perform evaluations based on such a specified initial state. In particular, the second heating and subsequent further cooling steps, in which crystallization can be observed, can be important and can be used to compare the curve state with a reference curve state. Such cooling steps make it possible to draw conclusions, for example, regarding additives that may be included in the sample as crystallization accelerators.

[0030] In one design, the heat flow from a temperature-controllable plate-like element into a sample, or vice versa, is detected between the temperature-controllable plate-like element and the side surface of the sample facing the temperature-controllable plate-like element, particularly by a heat flow meter, such as a planar heat flow meter, in the main surface area of ​​the plate-like or disk-like geometry adjacent to the temperature-controllable plate-like element. This allows for reliable, accurate, and direct detection of the heat flow. Bilateral detection of 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 positioned between the sample and a temperature-controllable plate element adjacent to the main surface, each in a central region of the main surface in a plate-like or disk-like geometry. In particular, each heat flow meter can occupy a large central region on the main surface. In some exemplary designs, the central region of the main surface occupied by the heat flow meter can be at least one-third or at least half the size of the main surface in each of two particularly orthogonal coordinate directions, as viewed from the main surface. In some exemplary designs, the central region occupied by the heat flow meter as the measuring surface can be at least one-ninth, at least one-sixth, or at least one-quarter of the surface area of ​​the main surface. This makes the effects of boundary effects, which are difficult to completely avoid, negligibly small or nonexistent due to the finite size of the sample and the temperature-controllable plate element. The planar extent of the heat flow meter in the large central region described above can include a large portion of the sample material, allowing useful information about the sample to be obtained. Increasing the proportion of the main surface occupied by the heat flow meter as the active measuring surface beyond the aforementioned value is advantageous for achieving further averaging across potentially non-uniform samples.

[0032] In a further configuration, before the temperature of the sample changes, one or both of the temperature-controllable plate-like elements are moved toward the sample, and a predetermined force is applied to the sample in the thickness direction of the plate-like or disk-like geometry via the temperature-controllable plate-like elements, or the predetermined thickness of the sample is adjusted in the thickness direction of the plate-like or disk-like geometry. This allows predetermined conditions, such as a predetermined thickness of the sample, to be set for the analysis to be performed, ensures reliable contact with the sample material for predetermined temperature control, and guarantees the smallest and most uniform heat transfer resistance at the contact surface.

[0033] In one design, the sample material is particularly assumed to be provided with a casing that encloses the sample material within a closed volume. Alternatively, in another design, the sample material is particularly assumed to be surrounded circumferentially at the edge of the sample by a flexible sealing element, the flexible sealing element extending substantially in the thickness direction of the sample over the thickness or filling height of the sample and formed together with a temperature-controllable plate-like element to surround the closed sample volume. In this case, the sealing element is particularly configured to make sealing contact with the temperature-controllable plate-like element. By providing the casing or sealing element as a kind of edge, it is possible to prevent the outflow of the sample material that liquefies during melting. Due to its flexibility, the sealing element preferably also allows tracing by moving the plate-like element in order to maintain contact between the sample material and the plate-like element during melting.

[0034] According to one design, the temperature of a sample is to be detected on the surface of the sample or inside the sample, and / or the temperature of temperature-controllable plate elements is to be detected on the surface of these temperature-controllable plate elements or inside the temperature-adjustable plate elements.

[0035] In a further configuration, the comparison between the curve state and the reference curve state is performed by using corresponding horizontal and / or vertical coordinate values ​​that characterize the curve shape and the reference curve shape, at least partially.

[0036] In other further configurations, the comparison between the curve state and the reference curve state is performed by profiles obtained with respect to the heat flow profile or with respect to the temporal change in temperature, as well as by at least one characteristic level and / or at least one characteristic extremum, particularly a peak, in the reference profile, where the level or extremum corresponds in particular to a transformation within the sample material.

[0037] In one design, at least one transverse coordinate value corresponding to a start point, end point, midpoint, transition point, or extremum assigned to a level or extremum within a curved shape is determined for at least one level or at least extremum, particularly a peak, obtained with respect to the temporal variation of heat flow or temperature, and compared with the corresponding transverse coordinate value in at least one reference profile.

[0038] Further design allows the height of a level to be determined for at least one level in a profile obtained with respect to the temporal variation of heat flow or temperature and compared with at least one height of at least one level in at least one reference profile, and / or the extreme value assigned to the temporal variation of heat flow or temperature to be determined for at least one extreme value, in particular a peak, in a profile obtained with respect to the temporal variation of heat flow or temperature and compared with at least one extreme value, in particular a peak, in at least one reference profile.

[0039] The above-described explanations and further configurations, which can be combined for further improvement, make it possible to reliably identify the components.

[0040] In a further configuration, at least one characteristic integral value, in particular, the plane below at least one section of a profile obtained with respect to the temporal change of heat flow or temperature represented as a curve, for example, the plane below the peak, is determined and compared with the characteristic integral value of a reference profile. In this further configuration, the identification of at least one component in the sample material is additionally performed based on the comparison of the characteristic integral values. This can contribute to further improvement of identification. The integral value can correspond to, for example, the enthalpy difference in the case of a phase transition in the sample, or to the difference in specific heat capacity in the case of, for example, a glass transition in the sample.

[0041] In further design, the profiles obtained regarding the temporal variation of heat flow or temperature are directly compared as a whole to a reference profile.

[0042] In a further configuration, the comparison of the curve state, particularly the curve shape, with the reference curve state, particularly the reference curve shape, involves the use of pattern recognition algorithms, such as adaptive algorithms and / or artificial intelligence methods.

[0043] The accuracy and reliability of identification can be further improved by directly comparing and / or using pattern recognition or artificial intelligence.

[0044] According to one design, multiple pre-determined profiles relating to the temporal changes in heat flow or temperature for a known sample material or sample material mixture are used as reference profiles.

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

[0046] Since multiple reference profiles can be used based on a data set, for example, provided in the form of a database, it is possible to provide reliable information about a wide range of potential contaminants or pollutants in a sample. Such a method can be extremely useful, for example, for managing recycling processes where complete certainty about the starting materials is rarely obtained.

[0047] Data collections, such as databases, can be provided, for example, on appropriate storage media, or they can be accessed via a network.

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

[0049] In other further configurations, the sample material is provided as aggregates.

[0050] Providing the material in loose or solid form allows for the use of various types of samples.

[0051] According to one design, the detection of heat flow or temperature profiles is performed without simultaneous reference measurements, particularly those geometrically corresponding to the sample and formed from known materials, or without blank measurements as a reference within the same analytical instrument or using the same additional analytical instrument. 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 is not required in the analytical instrument. Therefore, a simplified analysis tailored to the purpose of the sample material is possible while avoiding potential sources of error.

[0052] In one design, the sample to be analyzed has a mass of more than approximately 10 grams, for example, approximately 10 grams to approximately 10 kilograms, preferably approximately 10 grams to approximately 1 kilogram, and more preferably approximately 10 grams to approximately 200 grams, for example, approximately 10 grams to approximately 100 grams. Such samples make it possible to obtain reliable and representative information for larger material batches, such as those found on an industrial scale in the recycling field.

[0053] Further configuration suggests that the sample material is a mixture, and that one or more materials contained in the sample are to be identified by this method.

[0054] In a favorable design, this method is used to determine the purity of recycled plastic materials, in particular to identify potential mixtures or contaminants, and / or to determine their extent.

[0055] This method is used in the process chain during plastic recycling. Therefore, it is possible to manage the recycling process at different stages in a time-saving and simplified manner, as well as to control the quality of the resulting final product, such as the recycled plastic granules.

[0056] In a further exemplary configuration, a composite material mixture, particularly a composite plastic, is provided as the sample material for the sample. The present invention also advantageously allows for the analysis of plastics that have thus already been treated with respect to their components.

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

[0058] The accompanying drawings are included herein, and are part thereof, to provide a further understanding of the present invention. The drawings illustrate embodiments of the present invention and, together with the description herein, are intended to illustrate the principles of the present invention. Many other embodiments and advantages of the present invention can be readily understood by referring to the detailed description below. The elements of the drawings are not necessarily drawn to the same scale as one another. The same reference numerals represent similar parts. [Brief explanation of the drawing]

[0059] [Figure 1] This is a schematic cross-sectional view showing an apparatus used to carry out a method according to an exemplary embodiment of the present invention. [Figure 2] This is a schematic perspective view showing the plate-like or disc-like shape of the sample material used to carry out the method according to the exemplary embodiment, or the plate-like or disc-like shape of the spatial area in which the sample material is placed to carry out the method according to the exemplary embodiment. [Figure 3] Figure 1 shows a graph illustrating exemplary measurement results obtained by the apparatus schematically shown and used to identify at least one component in a sample material, for example, a polylactic acid (PLA) sample, according to an exemplary embodiment. [Figure 4] This graph shows exemplary measurement results for polylactic acid (PLA) obtained by the conventional differential scanning calorimetry (DSC) method, illustrating the results of two heating cycles. [Figure 5]Figure 1 shows a graph illustrating exemplary measurement results obtained by the apparatus schematically shown and used to identify at least one component in a sample material, for example, a paraffin sample, according to a further exemplary embodiment. [Figure 6] This graph shows exemplary measurement results for paraffin obtained by conventional differential scanning calorimetry (DSC). [Figure 7] This is a schematic flowchart of a method according to an exemplary embodiment of the present invention. [Figure 8] This is a schematic diagram showing an exemplary casing for a sample material for carrying out a method according to an exemplary embodiment of the present invention. [Figure 9] This is a schematic diagram showing edge-side sealing elements surrounding a sample material for carrying out a method according to an exemplary further embodiment. [Modes for carrying out the invention]

[0060] Unless otherwise specified, the same reference numeral in the drawings refers to the same or functionally similar component. All terms indicating direction, such as “up,” “down,” “left,” “right,” “upward,” “downward,” “horizontal,” “vertical,” “back,” “front,” and similar terms, are used for illustrative purposes only and do not limit the embodiments shown in the drawings to any particular arrangement.

[0061] Figure 1 shows an apparatus 100 that can be used to carry out a method according to an exemplary embodiment of the present invention described below. The apparatus 100 is used for the purpose of analyzing a sample 1. To provide the sample 1, for example, a sample material taken from a batch of loose plastic granules obtained in a recycling process is placed in a spatial region having a plate-like or disc-like geometry (shape) 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 1 of the sample material may be a cohesive solid, or alternatively, a compressible object (e.g., individually tailored) having a plate-like or disc-like geometry 2. Figure 2 schematically shows this type of plate-like or disc-like geometry 2. In Figure 2, the geometry 2 is formed in a flat, rectangular parallelepiped shape, and the extension of the geometry 2 in two mutually orthogonal coordinate directions x and y is significantly larger than the extension of the geometry 2 in a thickness direction D orthogonal to x and y, or thickness t. The main surfaces 21 and 22 of geometry 2 are substantially the same shape and dimensions, are formed parallel to each other, and are rectangular in the exemplary embodiment shown in Figure 2, for example.

[0062] The sample material of Sample 1 is a mixture containing at least one main material, regardless of its physical form, such as granules or aggregates. This mixture may contain one or more other materials, particularly contaminants of the main material, which are desired to be as pure as possible due to the involvement of a recycling process. Thus, the sample material contains one or more components, and this term refers not only to the main component but also to undesirable contaminants.

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

[0064] In the apparatus 100 shown in Figure 1, the heat flow from temperature-controllable elements 3 and 4 through the main surfaces 21 and 22 into the sample material, or from the sample material into elements 3 and 4, can be measured by heat flow meters 5 and 6 at both temperature-controllable sides 11 and 12 of the sample 1. Side 11 of the sample 1 faces temperature-controllable element 3, and side 12 faces temperature-controllable element 4. The heat flow meters 5 and 6 are configured to detect the heat flow passing through them. For example, the heat flow meters 5 and 6 can provide an output signal proportional to the heat flow passing through them, and from this output signal, the absolute value of the heat flow can be obtained after calibration.

[0065] The heat flow meters 5 and 6 are each formed in a planar shape and positioned in the central regions of their respective main surfaces 21 and 22. The outline of heat flow meter 5 is illustrated schematically and schematically by a dotted line in Figure 2, and heat flow meter 6 is positioned similarly and symmetrically to heat flow meter 5 in the opposite main surface 22 region.

[0066] The heat flow meters 5 and 6 each occupy a relatively large central region of the main surfaces 21 and 22, respectively. This central region, when viewed in relation to the main surfaces 21 and 22, has an area of ​​at least one-third of the dimensions of the main surfaces 21 and 22 in both the x and y coordinate directions. This minimizes the effects of boundary effects while simultaneously detecting heat flow passing through a large area of ​​the sample material. In Figure 2, for example, each heat flow meter 5 and 6 occupies a central region corresponding to approximately one-quarter of the surface area of ​​the main surfaces 21 and 22 as its active measurement surface. However, other, particularly larger surface areas can also be considered to further improve the averaging of sample 1.

[0067] The device 100 further comprises a heat sink 9 assigned to a temperature-controllable plate-shaped element 3 and extending parallel to element 3, and a heat sink 10 assigned to a temperature-controllable plate-shaped element 4 and extending parallel to element 4. The heat sinks 9 and 10 themselves are cooled by a cooling system 50.

[0068] Furthermore, temperature control systems 7 and 8 for temperature control are located between the heat sink 9 and element 3, and between the heat sink 10 and element 4, respectively. The temperature control systems 7 and 8 can be configured as heating units or together with heating units, such as resistance heating units. For example, this is advantageous when applying the present invention to the field of plastic recycling, where a temperature range that may include temperatures above 200°C can be well covered by this type of heating unit. When lower temperatures are used in other applications of the present invention, the temperature control systems 7 and 8 may be configured as Peltier systems instead. Peltier systems can offer the advantage of providing both heating and cooling.

[0069] The assembly formed by the heat sink 9, the temperature control system 7, and the plate-like element 3 can be further displaced by the displacement unit 30 substantially perpendicular to the main extension plane of the sample 1, and therefore perpendicular to the main surfaces 21 and 22. The unit 30 can apply a force F to the sample 1 in the thickness direction D. The displacement path or the thickness t of the sample 1 can be detected by the thickness measuring unit 40 in the thickness direction D of the sample 1. In one modification, both elements 3 and 4 are displaceable vertically and toward the sample 1, in addition to the heat sinks 9 and 10 and temperature control systems 7 and 8 assigned to them, respectively.

[0070] The temperature control systems 7,8, the cooling system 50, the displacement unit 30, the thickness measuring unit 40, the heat flow meters 5,6, and any additional temperature sensors, such as thermocouples, which can be provided in different combinations in locations described in more detail below, are coupled to the data processing and control system 60. This data processing and control system 60 can control each unit and systems 30,50,7,8 in particular, and process the measurements detected by unit 40, the heat flow meters 5,6, and the aforementioned temperature sensors. The system 60 can also be additionally coupled to input / output units (not shown), storage (not shown), and further units. Furthermore, it is conceivable that the system 60 may be coupled to a network interface.

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

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

[0073] Figure 7 shows a method for identifying at least one component in the sample material that forms sample 1.

[0074] In the first step S1 of this method, sample 1 is provided as described above, in which case the sample material is arranged as loose material, such as granules, in a spatial region having a plate-like or disk-like geometry 2 (see Figure 2). Alternatively, the sample material of sample 1 is formed in step S1 as a plate-like or disk-like geometry 2, for example, as a compressed solid or a compressible object. The mass of 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 preferable mass of sample 1 is, for example, in the range of about 10 grams to about 100 grams. Depending on the mass of sample 1, the dimensions can be adapted to correspond to the apparatus 100, for example, with respect to dimensions, mechanical stability, and heating and cooling capacity.

[0075] In the second step S2, the sample 1 is placed between two temperature-controllable plate-like elements 3 and 4. This arrangement is made such that the temperature-controllable plate-like elements 3 and 4 extend along one of each of two substantially flat main surfaces 21 and 22 that are opposite each other in geometry 2. Thus, the sample 1 and the plate-like elements 3 and 4 are arranged parallel to each other in a substantially sandwich-like manner. In this case, the planar heat flow meter 5 is placed between the main surface 21 and element 3, and the planar heat flow meter 6 is placed between the main surface 22 and element 4. Preferably, the heat flow meters 5 and 6 are fixedly incorporated into the plate-like elements 3 and 4, respectively, and come into contact with the main surfaces 21 and 22 after the sample 1 is placed between elements 3 and 4.

[0076] To prevent leakage of the sample material during subsequent heating and melting or liquefaction phase transitions or glass transitions, the sample material of the sample is enclosed in a casing 70 or a flexible sealing element 80 in exemplary embodiments (see Figures 8 and 9). In this case, the casing 70 or sealing element 80 is schematically shown together with elements 3 and 4, which are still separated from the sample 1. The casing 70 or sealing element 80 can be used as an alternative in the apparatus 100 of Figure 1 to carry out the method of the exemplary embodiment described herein, but is not shown in Figure 1 for improved visibility.

[0077] The casing 70 shown in Figure 8 completely encloses the sample material of sample 1, sealing it within a closed volume. The casing 70 can be made of a flexible material. In contrast, the sealing element 80 shown in Figure 9 surrounds the sample material of sample 1 in a frame-like manner along the circumference of sample 1 on the edge side of sample 1. In this case, the sealing element 80 can form a seal by contacting the temperature-controllable plate-shaped elements 3 and 4.

[0078] In step S2, after the sample 1 is positioned between elements 3 and 4 in the manner described above, the upper configuration shown in Figure 1, which includes a plate-shaped element 3, a temperature control system 7 assigned to this plate-shaped element 3, and a heat sink 9, is moved toward the sample 1 by the displacement unit 30. This allows for low heat transfer resistance, uniform and specified contact on the main surfaces 21 and 22, and in the case of compressible materials and / or bulk materials, a specified thickness t of the sample material can be achieved. Specified adjustment and control with respect to the thickness t is possible by the thickness measuring unit 40. The displacement unit 30 is preferably controlled by a data processing and control system 60. This data processing and control system 60 is additionally connected to the measuring unit 40 and can record the detected distance or thickness values, take these values ​​into consideration during the control of the displacement unit 30, and save these values ​​for display and / or documentation. In this case, the displacement unit 30 can apply a predetermined force or load F to the sample 1. The load F can be detected by a force measuring unit (not shown in Figure 1) and adjusted to a target value. When the sealing element 80 is used, the method described above is carried out by the displacement unit 30 so that the sealing element 80 comes into contact with both elements 3 and 4 to form a seal.

[0079] In the third step S3a or S3b, a temperature change is introduced to the sample 1. For this purpose, a heat inflow Qz into the sample 1 or a heat outflow Qa from the sample 1 is introduced symmetrically through two main surfaces 21, 22 in the plate-like or disk-like geometry 2. The symmetric operating mode of the apparatus 100, given the precision achievable with the components of the apparatus 100 and the sufficient uniformity of the sample 1, allows substantially half of the total heat flow to flow in or out through one of the temperature-controllable plate-like elements 3, 4.

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

[0081] The temperature changes occurring in the third steps S3a and S3b cover a temperature range in which at least one endothermic or exothermic change occurs in at least one component of the sample material. Such changes are preferably phase transitions, such as the melting or solidification of at least one or more components of the sample material, or a glass transition of one or more such components, or, if one component has, for example, a ratio of crystalline and amorphous materials, a phase transition and a glass transition.

[0082] According to alternative and exemplary embodiments of the present invention, two different methods are provided for inducing a temperature change. This is illustrated in Figure 7 by two alternative steps, S3a or S3b.

[0083] According to step S3a, the temperature change is performed such that the sample material is exposed to a predetermined temperature profile stored in a memory unit (not shown) accessible by, for example, the data processing and control system 60. This temperature profile is continuously selected, particularly as a predetermined temperature ramp, and rises or falls linearly over time, covering the temperature range described above. In this case, the temperature is detected, for example, by a temperature sensor or a plurality of temperature sensors on the main surfaces 21, 22 or both main surfaces 21, 22 of the sample 1, or inside the sample 1. Alternatively or additionally, the temperature sensor may also detect the temperature on the surface of plate-like element 3 facing the main surfaces 21, 22, or on the surface of plate-like element 4, or on the surfaces of both plate-like elements, or inside one or both of plate-like elements 3, 4. The defined temperature profile can correspond to the temperature of one of these locations, or to a temperature that can be modeled based on, for example, one or more of the temperatures of the temperature measurement points described above. In step S3a, the temperature change is applied symmetrically from both sides 11, 12 of the sample. If the temperature control in elements 3 and 4 is thus symmetrical, and therefore the operating mode and the temperature change of sample 1 occur symmetrically, the difference in the heat flow supplied or removed through elements 3 and 4, respectively, may differ if the non-uniformity of sample 1 is significant, due to the different heat capacities or thermal conductivity of the components of the sample material.

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

[0085] During the temperature change of sample 1 according to step S3a or S3b, the displacement unit 30 can be readjusted. This ensures good contact with sample 1 and good heat conduction to (and from) the plate-like elements 3 and 4, for example, in the event of a phase transition or glass transition accompanied by liquefaction.

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

[0087] Specifically, in step S4a, while sample 1 is exposed to a predetermined temperature profile, the heat flow into or out of sample 1 is detected by heat flow meters 5 and 6. The heat flow can be represented as a curve. JPEG0007901192000001.jpg56 or The profile of JPEG0007901192000002.jpg55 is obtained from the detected heat flow values ​​as a function of the temperature T of sample 1 or the temperature T of temperature-controllable plate-like elements 3 and 4, or as a function of time t.

[0088] Alternatively, in step S4b, a predetermined and constant heat flow is applied to sample 1, and the temperature of sample 1 or the temperature-controllable plate-like elements 3,4 is detected while the heat flow is introduced into or removed from sample 1. The temperature profile over time can be represented as a curve. JPEG0007901192000003.jpg511 or JPEG0007901192000004.jpg512 is obtained from the detected temperature value as a function of temperature or as a function of time.

[0089] In steps S4a and S4b, the temperature of sample 1 or plate-like elements 3 and 4 can be detected at the locations described above with respect to steps S3a and S3b.

[0090] In the fifth step S5, the curve state of the obtained profile, which can be represented as a curve, is defined as the heat flow. JPEG0007901192000005.jpg56 or Curve state or temperature change over time in JPEG0007901192000006.jpg55 JPEG0007901192000007.jpg511 or The curve state of JPEG0007901192000008.jpg512 is preferably compared with the reference curve states of several reference curves, or more preferably with multiple reference curve states.

[0091] This will be explained in more detail below. The reference curve was previously analyzed for various known sample materials using the same apparatus 100, particularly under the same conditions and the same heat flow program temperature and measurement points as during the analysis of the actual sample 1, and the results were stored in a database accessible by the data processing and control system 60. JPEG0007901192000009.jpg56 or JPEG0007901192000010.jpg55 or JPEG0007901192000011.jpg511 or This is stored in advance as the reference curve for JPEG0007901192000012.jpg512.

[0092] In this case, the reference curve can be measured in advance for known homogeneous sample material, known sample material mixture having two or more known components, or for expected undesirable 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, such as plastics and plastic mixtures, each adapted to its respective application. The database can be provided on a suitable storage medium (not shown) or made accessible from a remote storage medium via a network.

[0094] Based on the comparison results, in step 6 S6, at least one component in the sample material is identified, or multiple components in the sample material are identified.

[0095] Figure 7 shows by dashed lines that steps S3a, S4a or S3b, S4b can be repeated, respectively. Therefore, for example, several heating and / or cooling processes can be performed using temperature-controllable plate-like elements 3, 4, repeatedly heating and cooling the sample material or at least one component, 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, and can be used for identification depending on the sample material or its components. In this case, for example, the comparison step S5 can be performed immediately after detecting a profile that can be represented as a curve, as illustrated in Figure 7, or alternatively, all provided heating / cooling processes can be performed first, the obtained curve profiles can be stored, and then compared together in step S5. Furthermore, it is not necessarily required that all profiles obtained with respect to the heating / cooling processes be considered for comparison, and it is conceivable that a defined selection of options may be provided. In particular, it is advantageous to use samples that have been heated a second time for comparison, because this heating process allows us to assume a uniform initial state.

[0096] The evaluation in step S5 is based on heat flow relative to temperature. JPEG0007901192000013.jpg56 or time By applying JPEG0007901192000014.jpg55, or by changing the temperature over time. JPEG0007901192000015.jpg511 or temperature This is done by applying JPEG0007901192000016.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 includes, in particular, a comparison between the curve shape of the curve applied for sample 1 and the curve shape of the reference curve.

[0098] Transformations within the sample material are represented by levels or extrema in these curve profiles. Comparison of the curve state with a reference curve state can be performed using corresponding horizontal and / or vertical coordinate values, which at least partially characterize the curve shape and the reference curve shape. For example, heat flow JPEG0007901192000017.jpg55, JPEG0007901192000018.jpg56 or temperature change JPEG0007901192000019.jpg511, JPEG0007901192000020.jpg512 or the y-coordinate values, for example the temperatures at which extreme values ​​occur, are measured for sample 1 and applied to determine the start temperature, end temperature, and / or midpoint temperature of the curve, in addition to determining the sample composition based on, for example, the integration plane below the peak. For this purpose, the characteristic temperature, in particular, as a characteristic y-coordinate value, not only the start temperature, end temperature, midpoint temperature, and extreme value temperature mentioned above, but also, if applicable, the integral value and / or the entire curve profile, is compared with reference curves in the database and corresponding characteristic temperatures predetermined for these reference curves. The y-coordinate values ​​assigned to the characteristic y-coordinate values ​​mentioned above can also be compared. The database includes reference curves for pure substances and mixtures relevant to the application.

[0099] As part of the evaluation in step S5, for example, in some exemplary embodiments of the method, it is further conceivable that the height of at least one level of the obtained profile with respect to the temporal change of heat flow or temperature is determined and compared with the height of at least one level of the reference curve. Similarly, for example, the extreme values ​​of the curve of heat flow or temporal temperature change can be used as the y-coordinate values ​​and directly compared with the y-coordinate values ​​of the extreme values ​​of the reference curve.

[0100] The characteristic integral value with respect to at least one section below the plane in the curve relating to the temporal change of heat flow or temperature obtained for analyzing sample 1 can be additionally calculated during the evaluation in step S5 to further improve the evaluation and can be compared with the integral value of the reference curve.

[0101] In step S5, an exemplary embodiment is also conceivable in which the profile obtained with respect to the temporal change of heat flow or temperature is directly compared as a whole with a reference profile. In this case, the curve shape and the reference curve state are preferably compared with each other by using a pattern recognition algorithm, such as an adaptive algorithm and / or an artificial intelligence method.

[0102] In some exemplary embodiments of step 5S, if a material mixture is present in sample 1, it is further conceivable that the resulting curve, in other words, the curve obtained for the temporal change of heat flow or temperature applied to time or temperature, respectively, be "fitted" to several reference curves; that is, the actual measurement results are fitted to several reference curves, and the composition of the sample material of sample 1 is concluded from the weighted results obtained for each reference curve. For example, in such a fitting, characteristic peaks can be assumed for each curve, and in this case, for the purpose of fitting, for example, the focus is on the curve section having such peaks.

[0103] According to exemplary embodiments of the present invention, the heat flow curves obtained for a temperature change applied in the form of a linear lamp using an apparatus 100 such as the HFM shown in Figure 1, and thus 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. Several characteristic values ​​that identify the curve shape in each illustrated section are: This was derived from the JPEG0007901192000021.jpg56 curve and is shown in Figures 3 and 5.

[0104] Figure 3 shows, for example, that the glass transition of PLA occurs at a level of approximately 65°C during the "HFM measurement" of the second heating, with the midpoint of that level being 64.2°C. In Figure 3, heat flow JPEG0007901192000022.jpg52 is expressed in arbitrary units (abbreviated as au) in order to particularly show the curve shape and its characterization. In comparison, Figure 4 shows the conventional measurement results by DSC (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 midpoint of the 65.8°C level corresponding to the glass transition is obtained by the conventional DSC method during the first heating, and the level of 61.7°C is obtained by the conventional DSC method during the second heating.

[0105] When the results obtained for the second heating according to the exemplary embodiment of the present invention in Figure 3 are compared with the DSC results obtained for the first and second heating in Figure 4, they generally show good similarity in curve shape and numerical values. Thus, it is possible to obtain results like DSC by 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 created by, for example, apparatus 100, in a manner such as HFM of the present invention, in order to achieve the best possible comparability.

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

[0107] In the evaluation of the heat flow profile, as illustrated in Figure 5 and carried out by the method according to the exemplary embodiment, the heat flow profile was measured for paraffin 6062 during the first heating in a continuous temperature change in the form of a linear ramp with a gradient of 1 Kelvin per minute by the apparatus 100 in Figure 1. In Figure 5, the horizontal and vertical coordinate values ​​of the two peaks, as well as further temperature values ​​characterizing the curve shape, are shown, along with the integral value shown in shaded areas below the section of the obtained curve. Figure 5 shows the melting transition of paraffin 6062. Note that in the case of paraffin 6062, very similar results are obtained for the second heating. In comparison, the results of a conventional DSC measurement for the first heating of the same paraffin are shown in Figure 6, and are in good agreement with the results in Figure 5 obtained according to the exemplary embodiment of the present invention, particularly with respect to the curve shape.

[0108] For example, when different paraffins 6062 and 5254 are analyzed according to yet another exemplary embodiment and the measurement results are evaluated, their melting occurs as a maximum value in the temperature range between 50°C and 70°C.

[0109] The method based on the exemplary embodiments described above can be used, for example, to measure the purity of recycled plastic materials, such as granules produced from recycled plastics. The method according to the exemplary embodiments described above provides a simple, time- and cost-saving, as well as accurate and reliable option for determining whether and to what extent the granules contain mixtures or contaminants from the recycling process, particularly other plastics. In the exemplary embodiments described above, in which heat is symmetrically introduced into or removed from the sample 1 through the main surfaces 21, 22 of a plate-like or disc-like geometry 2, relatively large samples with respect to the sample material can be used, thus enabling the analysis of batches on an industrially significant scale, such as during a recycling process. The effort required to analyze the batch is manageable and feasible.

[0110] Batch analysis by analyzing Sample 1 can be easily, quickly, and efficiently used, for example, in the granule manufacturing process for quality control of shipping batches, or similarly in incoming inspections at customer facilities, such as plastics processors, providing reliable and accurate results. The sample material of Sample 1 may be an already composite plastic.

[0111] In the present invention, there is an advantage that it is not necessary to measure a reference material or perform a blank measurement as a reference simultaneously with the measurement of the actual analyte, i.e., sample 1. This is typically done, for example, by using a second blank crucible in the conventional DSC method. The apparatus 100 shown in Figure 1 does not include a unit for performing a reference measurement simultaneously, as used in the exemplary embodiments described herein. A blank "twin" as a reference in the apparatus 100 is also not required to carry out the method according to the exemplary embodiments described herein. Thus, the effort required to carry out 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 the sample material being analyzed, the apparatus 100 can be configured similarly to generally known HFM apparatuses, such as those described in ATMS C 1784, and the observed exothermic / endothermic processes can be modified according to the temperature expected in the sample material. In this case, for example, an HFM apparatus for carrying out the method described in the exemplary embodiment described above can be modified to accommodate higher and / or lower and / or wider temperature ranges that the apparatus enables and is suitable for, for example, with respect to the performance, layout, or dimensions of the heating and cooling units 7,8,9,10, possibly the sealing material, and other components. When applied to the field of plastic recycling, the apparatus 100 can be configured such that, for example, the phase transitions and / or glass transitions of plastics assumed to be the main components and contaminants of the sample material are reliably captured by the temperature range achieved by the apparatus 100.

[0113] Although the present invention has been fully described above based on preferred and exemplary embodiments, the present invention is not limited thereto and can be modified in various ways. [Explanation of Symbols]

[0114] 1 sample 2. Plate-shaped or disc-shaped geometry 3,4 Temperature-controllable plate-shaped element 5,6 Heat flow meter (heat flux converter) 7,8 Temperature control system 9,10 Heatsink 11 First aspect 12 Second aspect 21 1st main surface 22 Second main surface 30 Displacement Units 40 Thickness measuring unit 50 Cooling System 60 Data Processing and Control Systems 70 Casing 80 seal elements 100 devices 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 directions

Claims

1. A method for identifying at least one component in a sample material forming a sample (1), The step of preparing the sample (1) is to place the sample material in a spatial region defined by a plate-shaped or disk-shaped geometry (2), The step of arranging the sample (1) between two temperature-controllable plate-shaped elements (3, 4) such that the temperature-controllable plate-shaped elements (3, 4) extend along one of each of the two opposing main surfaces (21, 22) in the plate-shaped or disk-shaped geometry (2), A step of causing a temperature change in the sample (1) by symmetrically bringing heat inflow (Qz) into the sample (1) or symmetrically bringing heat outflow (Qa) from the sample (1) through the two main surfaces (21, 22) of the plate-like or disk-like geometry (2), wherein the temperature change is caused by temperature control of the plate-like elements (3, 4), and the temperature change covers 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 flowing into or out of the sample (1) is detected, and a profile of the heat flow, which can be expressed as a curve as a function of time, is obtained from this. Or, The steps include detecting the temperature of the sample (1) or the temperature-controllable plate-shaped elements (3, 4), and obtaining a profile of the temporal change of the temperature that can be represented as a curve, The steps include comparing the curve state of the profile obtained with respect to the temporal change of the temperature or the heat flow with the reference curve state of one or more reference profiles, A step of identifying at least one component in the sample material based on the comparison result, Methods that include...

2. A method according to claim 1, characterized in that when the temperature change of the sample (1) is brought about, the sample material is exposed to a continuous temperature profile.

3. A method according to claim 1, characterized in that the temperature change of the sample (1) is brought about by supplying a constant heat flow to the sample (1) over time or by removing it from the sample (1).

4. A method according to any one of claims 1 to 3, characterized in that 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.

5. A method according to any one of claims 1 to 3, characterized in that the sample material completely or partially melts or solidifies during the temperature change.

6. A method according to any one of claims 1 to 3, characterized in that the sample material is exposed to two or more temperature change processes by controlling the temperature of the temperature-controllable plate-like elements (3, 4).

7. A method according to any one of claims 1 to 3, characterized in that a heat flow from the temperature-controllable plate-like elements (3, 4) into the sample (1), or vice versa, from the sample (1) to the temperature-controllable plate-like elements (3, 4), is detected between the temperature-controllable plate-like elements (3, 4) and the side surfaces (11, 12) of the sample (1) facing the temperature-controllable plate-like elements (3, 4) in the main surface (21, 22) region of the plate-like or disk-like geometry (2) adjacent to the temperature-controllable plate-like elements (3, 4).

8. A method according to claim 7, characterized in that a heat flow meter (5, 6) is placed between the temperature-controllable plate-shaped element (3, 4) adjacent to the main surface (21, 22) and the sample (1) in a central region of the main surface (21, 22) in the plate-shaped or disk-shaped geometry (2).

9. A method according to any one of claims 1 to 3, characterized in that, before causing the temperature change of the sample (1), one or both of the temperature-controllable plate-like elements (3, 4) are moved toward the sample (1), a predetermined force is applied to the sample (1) in the thickness direction (D) of the plate-like or disk-like geometry (2) via the temperature-controllable plate-like elements (3, 4), or a predetermined thickness (t) of the sample (1) is adjusted in the thickness direction (D) of the plate-like or disk-like geometry (2).

10. A method according to any one of claims 1 to 3, characterized in that 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-like elements (3, 4) is detected on the surface of the temperature-controllable plate-like elements (3, 4) or inside the temperature-controllable plate-like elements (3, 4).

11. A method according to any one of claims 1 to 3, characterized in that the comparison between the curve state and the reference curve state is performed by using corresponding horizontal and / or vertical coordinate values ​​that at least partially characterize the curve shape and the reference curve shape.

12. A method according to any one of claims 1 to 3, characterized in that the comparison between the curve state and the reference curve state is performed by a profile obtained with respect to the profile of the heat flow or a profile obtained with respect to the temporal change of the temperature, and at least one characteristic level and / or at least one characteristic extremum in the reference profile.

13. A method according to any one of claims 1 to 3, characterized in that at least one transverse coordinate value corresponding to a start point, end point, midpoint, turning point, or extremum assigned to at least one characteristic level or at least one characteristic extremum in the profile within the curve shape is determined for the at least one level or at least extremum obtained with respect to the profile of the heat flow or the temporal change of the temperature, and is compared with the corresponding transverse coordinate value in at least one reference profile.

14. A method according to any one of claims 1 to 3, characterized in that the height of at least one characteristic level in the profile is determined for at least one level in the profile obtained with respect to the temporal change of the heat flow or the temperature, and compared with at least one height of at least one level in at least one reference profile, and / or an extreme value assigned to the temporal change of the heat flow or the temperature is determined for at least one extreme value in the profile obtained with respect to the profile of the heat flow or the temporal change of the temperature, and compared with at least one extreme value in at least one reference profile.

15. A method according to any one of claims 1 to 3, characterized in that at least one characteristic integral value is determined, compared with the characteristic integral value of the reference profile, and at least one component in the sample material is identified additionally based on the comparison result of the characteristic integral value.

16. A method according to any one of claims 1 to 3, characterized in that a profile obtained with respect to the temporal change of the heat flow or the temperature is directly compared as a whole with the reference profile.

17. A method according to any one of claims 1 to 3, characterized in that the comparison of the curve state with the reference curve state includes the use of a pattern recognition algorithm.

18. A method according to any one of claims 1 to 3, characterized in that a plurality of profiles relating to the temporal change of the heat flow or temperature, which have been determined in advance for a known sample material or a mixture of sample materials, are used as reference profiles.

19. A method according to any one of claims 1 to 3, characterized in that the reference profile is provided in the form of a data set, the data set includes selective reference profiles specific to the applications of pure substances and mixtures.

20. A method according to any one of claims 1 to 3, characterized in that the sample material is provided as a loose material having a plurality of individual small pieces, or as an aggregate.

21. A method according to any one of claims 1 to 3, characterized in that the detection of the profile of the heat flow or temperature is performed without a simultaneous reference measurement formed of a known material that is geometrically corresponding to the sample (1), or a blank measurement as a reference is performed in the same analytical apparatus (100) or without using the same further analytical apparatus (100).

22. A method according to any one of claims 1 to 3, characterized in that the sample (1) to be analyzed has a mass of more than about 10 grams.

23. A method according to any one of claims 1 to 3, characterized in that the sample material is a mixture, and one or more materials contained in the sample (1) are identified by the method.

24. A method according to any one of claims 1 to 3, characterized in that the method is used to determine the purity of recycled plastic material.

25. A method according to any one of claims 1 to 3, characterized in that the method is used in a process chain during plastic recycling.

26. A method according to any one of claims 1 to 3, characterized in that a composite material mixture is provided as the sample material of the sample (1).

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