Method for quality control of extruded polymeric materials

Abstract

The invention relates to a method for quality control of polymeric materials. In the quality control method of the invention, a polymer source material is extruded in a processing unit comprising at least one screw, after which an imaging system records an image of the extrudate. On the basis of the image, at least one macroscopic property, in particular at least one expansion-derived macroscopic property, and optionally at least one non-expansion-derived macroscopic property, of the extrudate is determined. Preferably at least one determined macroscopic property of the extrudate is compared to a database of macroscopic properties derived from a predetermined expansion of the extrudate from a polymer source material of known molecular composition to determine the quality of the extruded polymer material. The invention also provides a computer-implemented method and system for performing the quality control method. Also provided herein are methods for generating a database correlating macroscopic properties of a solid polymer source material with their molecular composition.

Description

Technical Field

[0001] The present invention relates to the field of quality control of extruded polymeric materials, and in particular recycled and / or blended polymeric source materials, e.g. for determining appropriate applications of polymeric source materials or for controlling production or processing lines of polymeric products such as polymer pellets. Background Art

[0002] Plastics, or polymers in general, are used in countless products. Many of today's plastics are complex multi-component systems or based on raw materials made from a variety of components, such as different polymer types, fillers, and additives. The systematic selection and blending of these components in appropriate mixtures produces materials with optimized properties and / or threshold characteristics. Since high product quality at a low price and with minimal waste is a fundamental requirement of modern industry, reliable quality control is essential. Therefore, a key step in the manufacturing process is to verify the nature of the incoming raw or source materials. For processing polymers (and their blends), it is necessary to assess the extent of multi-component behavior and predict flow behavior during processing. Therefore, the composition of the mixture can be adjusted (i) by, for example, renewing the masterbatch and / or adding additional material to the hopper unit of the processing unit, and / or (ii) by changing the processing conditions to achieve the desired quality of the polymer source material. These adjustments are preferably made via a feedback loop. The present invention primarily focuses on quality control in processing units involving polymer melts, but is not limited to melts alone, such as the processing of soft mix ingredients (e.g., pharmaceutical active ingredients or reactive components). In extreme cases, less concentrated polymer solutions are also considered.

[0003] The growing demand for sustainable materials and end-use applications presents a new set of challenges due to the inherent variability and contamination in waste plastic feedstock, especially when compared to more defined batches of virgin resin. Recycled polymer materials should preferably be incorporated without compromising the product performance expected by customers and consumers. Therefore, it is crucial to provide systems and methods that enable the quality classification of waste polymer materials so that they can be reused in the most appropriate applications.

[0004] Polymer materials are usually produced in the form of granules or pellets, which are then converted or further processed (e.g., via extrusion or injection molding) into so-called finished or end products, such as films or (upgraded) granules. Since granules are intended to be converted later, they are usually used as input material for standardized processing steps to produce the finished product. Therefore, in order to maintain the reliability of the later and / or early production processes, granules, including foils or injection molded parts, are subject to quality constraints.

[0005] Current methods for quality control are often offline, where small amounts of polymer source material or processed samples are analyzed, such as melt flow index, a measure of (Newtonian or low shear rate) viscosity; rheological response as a function of frequency / shear rate, such as via rotational rheometers, capillary rheometers, and extensional rheometers, which are measures of viscoelasticity; thermal properties (e.g., differential scanning calorimetry) with derived properties such as enthalpy of fusion and crystallinity; physical property tests (e.g., density and moisture measurements); mechanical tests (e.g., tensile strength and toughness measurements); color, such as via fluorescence spectroscopy; contaminants via microscopy; functional group identification via Fourier transform infrared spectroscopy; and / or gel permeation chromatography to assess molar mass or molecular weight distribution, or branching level. These offline measurements have the disadvantage that they are slow (e.g., at least several minutes to several hours) and discontinuous, and require extensive laboratory equipment, operators, and analysts to interpret the measured information. Furthermore, no real-time adjustments can be made to the polymer process while it is running.

[0006] There are also some quality control devices that actually use a modified die to separate a portion of the polymer melt stream during (extrusion) processing in a closed environment to measure pressure changes via a pressure sensor. These pressure changes are then interpreted based on simplified mathematical equations to evaluate the viscoelastic behavior of the processed polymer source material. Such pressure-driven methods lack the required visualization component to show that the flow behavior in a closed environment is actually required. Their correlation with microscopic (especially molecular) information about the properties of the multicomponents is also very basic.

[0007] There remains a need for reproducible quality control methods that can be applied on-line or in real time during the manufacturing or processing of virgin as well as recycled polymer streams.

[0008] There also remains a need for reproducible quality control methods that allow for continuous and / or more precise quality control, in particular of unknown polymer compositions and blends, such as recycled blends. Summary of the Invention

[0009] The present inventors have realized a method for quality control of extruded polymer materials, which relies on measuring macroscopic properties of a polymer material in a non-solid state, such as a molten state, to identify the molecular composition of a polymer source material. This, in turn, allows for (quality) grading of the polymer source material. In particular, the polymer source material is extruded and macroscopic properties derived from the (die) expansion properties of the extrudate are determined using an imaging system that records images of the extrudate at one location and, optionally, at different locations for different time frames or time intervals. The quality of the extruded polymer material is determined based on a comparison of one or more of the determined macroscopic properties with macroscopic properties derived from a predetermined expansion of an extrudate from a solid polymer source material of known molecular composition, thereby allowing for identification of the molecular composition of the polymer source material. Based on its molecular composition, the polymer source material can be quality-classified.

[0010] Advantageously, the quality control method of the present invention can be used with manufactured or processed virgin polymer source materials as well as recycled polymer source materials, and with polymer source materials composed of a single polymer type as well as blends of multiple polymer types. Preferably, the method is performed using recycled polymer source materials as a source of solid polymer material. In this way, the method allows quality control to be provided even for polymer sources of unknown or uncertain origin.

[0011] Advantageously, the quality control method of the present invention can be easily integrated into existing extrusion processes, which may also include one or more processing steps to obtain the final product. This allows the production process to be adjusted or optimized, for example by adjusting the composition of the polymer source material and / or by adjusting the conditions in the processing unit to achieve an extruded polymer material of a desired quality.

[0012] According to a first aspect, the present invention relates to a method for quality control of polymer materials. The method preferably comprises the following steps:

[0013] - extruding the polymer source material through an outlet orifice or a die in a processing unit comprising at least one screw; thereby obtaining an extrudate;

[0014] - preferably, using an extrudate flow modifying device, preferably an extrudate knife cutter system, to temporarily modify the flow of the extrudate;

[0015] - recording images of the extrudate at different time steps and optionally at different positions using an imaging system;

[0016] - determining at least one expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the recorded images; and,

[0017] - comparing at least one determined expansion-derived macroscopic property of the extrudate with a database of predetermined (ex-die) expansion-derived macroscopic properties of extrudates from polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material.

[0018] In some preferred embodiments, the polymer source material is a recycled polymer source material and / or a waste polymer source material.

[0019] In some preferred embodiments, the method further comprises the following steps:

[0020] - Using an extrudate flow changing device, preferably a knife cutter system, preferably an extrudate knife cutter system, to temporarily change the flow direction of the extrudate.

[0021] This step is preferably performed before the step of recording images to obtain images of the transient state.

[0022] In some preferred embodiments, the extrudate flow altering device further adjusts the extrudate flow in the x-direction, y-direction and / or z-direction. In some preferred embodiments, the extrudate flow altering device further adjusts the extrudate velocity in the x-direction, y-direction and / or z-direction.

[0023] In some preferred embodiments, the die is a mainstream die. In some preferred embodiments, the die is a side stream die.

[0024] In some preferred embodiments, the extrudate flow altering device temporarily alters the extrudate flow for 0.5 seconds to 20.0 seconds. Thus, a transition state can be achieved within 0.5 seconds to 20.0 seconds.

[0025] In some preferred embodiments, the image is recorded in a transient state and / or in a non-transient state at at least one location. In some preferred embodiments, the image is recorded in a transient state. In some preferred embodiments, the image is recorded in a non-transient state. In some preferred embodiments, the image is recorded in both a transient state and a non-transient state.

[0026] In some preferred embodiments, the method further comprises the following steps:

[0027] - Adjusting the composition of the polymer source material, and / or adjusting the operating conditions of the processing unit to achieve an extruded polymer material of the desired quality.

[0028] This step is preferably performed to provide a feedback loop between the step of determining the quality of the extruded polymeric material and the step of extruding the polymeric source material.

[0029] In some preferred embodiments, the method further comprises the following steps:

[0030] - determining at least one second macroscopic property of the extrudate, in particular at least one non-expansion-derived macroscopic property, optionally as a function of time and / or position, based on the recorded images and / or using a suitable measurement technique; preferably, wherein the measurement technique is selected from the group comprising: color spectrometry, infrared spectroscopy, laser technology, hyperspectral imaging, or a combination thereof; wherein the at least one second macroscopic property, in particular the at least one non-expansion-derived macroscopic property, is also used to determine the quality of the extruded polymeric material.

[0031] In some preferred embodiments, the method further comprises the following steps:

[0032] - preferably determining off-line at least one macroscopic property of the extrudate, in particular at least one additional non-expansion-derived macroscopic property, on a sample taken from the extrudate or the polymer source material; wherein the at least one macroscopic property determined off-line, in particular the at least one additional non-expansion-derived macroscopic property determined off-line, is also used for determining the quality of the extruded polymer material.

[0033] According to a second aspect, the present invention relates to a quality control system for polymer source materials. The quality control system is preferably configured to perform the method according to the first aspect and (preferred) embodiments thereof. The system preferably comprises:

[0034] a processing unit comprising at least one screw and an outlet orifice or die, the processing unit being configured to extrude the polymer source material through the outlet orifice or die;

[0035] - an imaging system configured to record images of the extrudate at different time steps and optionally at different positions; and,

[0036] a computer processor configured to determine, based on the recorded images, at least one expansion-derived macroproperty of the extrudate as a function of time and, optionally, position; and to compare the at least one determined expansion-derived macroproperty of the extrudate with a database of predetermined (ex-die) expansion-derived macroproperties of extrudates from polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material; and,

[0037] - Optionally, extrudate flow modification means, preferably an extrudate knife cutter system.

[0038] A (preferred) embodiment of the first aspect of the present invention is also a (preferred) embodiment of the second aspect of the present invention, and vice versa.

[0039] In some preferred embodiments, the system includes an extrudate flow altering device.

[0040] In some preferred embodiments, the imaging system comprises one or more cameras, which are optionally connected to a computer comprising a computer processor. In some preferred embodiments, the imaging system comprises one or more backlight sources. In some preferred embodiments, the imaging system comprises a fixture.

[0041] According to a third aspect, the present invention relates to a computer-implemented method for quality control of polymeric materials, preferably a computer-implemented method for quality control of polymeric materials according to the method of the first aspect and (preferred) embodiments thereof. Said computer-implemented method preferably comprises the following steps:

[0042] - receiving images from an imaging system, said images being recorded at different time steps and optionally at different positions of an extrudate of a polymer source material passing through an outlet orifice or a die in a processing unit comprising at least one screw;

[0043] - determining at least one expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the received images; and,

[0044] - comparing at least one determined expansion-derived macroscopic property of the extrudate with a database of predetermined (ex-die) expansion-derived macroscopic properties of extrudates from (preferably solid) polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material.

[0045] A (preferred) embodiment of the first or second aspect of the present invention is also a (preferred) embodiment of the third aspect of the present invention, and vice versa.

[0046] According to a fourth aspect, the present invention relates to a method for generating a database relating macroscopic properties of an extruded polymer material to its molecular composition. The method preferably comprises the following steps:

[0047] - extruding a polymer source material of known molecular composition and / or predetermined molecular composition through an outlet orifice or a die in a processing unit comprising at least one screw; thereby obtaining an extrudate;

[0048] - preferably, using an extrudate flow modifying device, preferably an extrudate knife cutter system, to temporarily modify the flow of the extrudate;

[0049] - recording images of the extrudate at different time steps and optionally at different positions using an imaging system;

[0050] - determining at least one expansion-derived macroscopic property and optionally at least one non-expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the recorded images; and,

[0051] - correlating at least one determined expansion-derived macroscopic property, and optionally at least one determined non-expansion-derived macroscopic property, of the extrudate with a known molecular composition and / or a predetermined molecular composition to generate a database.

[0052] A (preferred) embodiment of the first, second or third aspect of the present invention is also a (preferred) embodiment of the fourth aspect of the present invention, and vice versa.

[0053] In some preferred embodiments, the method further comprises the following steps:

[0054] - determining the molecular composition of the polymer source material or the extruded polymer material via simulations, preferably via kinetic Monte Carlo simulations based on coupling matrices.

[0055] In some preferred embodiments, the method further comprises the following steps:

[0056] - Determining the molecular composition of the polymer source material or the extruded polymer material via experimental analysis.

[0057] In some preferred embodiments, the database used in the first, second or third aspect of the present invention and its (preferred) embodiments is pre-acquired according to the fourth aspect of the present invention and its (preferred) embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The teachings of the present application are illustrated by the following drawings, which are to be considered merely illustrative and not to limit the scope of the claims in any way. The following numbering will be followed in the drawings:

[0059] 10 - Source material; 100 - Polymer extrusion system; 110 - Inlet stream; 120 - Processing unit with at least one screw; 130 - Connector extruder + orifice; 140 - Connector die + opening; 150 - Die; 151 - Main stream die; 152 - Side stream die; 160 - Extrudate (showing die swell); 161 - Main extrudate; 162 - Side extrudate; 171 - Knife cutting system; 180 - Finishing step; 200 - Imaging system; 211 - Camera 1; 212 - Camera 2; 220 - PC; 230 - Backlight; 240 - Fixture

[0060] Figure 1 A schematic diagram showing an arrangement for quality control of extruded polymeric material according to an embodiment of the present invention is shown.

[0061] FIG2 illustrates a die suitable for use with various embodiments of the present invention. Figure 2AProvided are images of a mainstream die (left) and a mid-section of the same die (right) suitable for use in quality control methods as described herein. Figure 2B Provided are images of a side stream die (left) and a mid-section of the same die (right) suitable for use in quality control methods as described herein. Figure 2C A diagram is provided of a side stream die comprising a first side stream die element connectable to a main stream die and a second side stream die configured to direct a side stream extrudate.

[0062] FIG3 illustrates an imaging system suitable for use with various embodiments of the present invention. Figure 3A An example of an imaging system suitable for use in the quality control method as described herein is provided, wherein the imaging system is focused on the extrudate exiting the main flow die. The imaging system comprises two cameras, each connected to a computer. Figure 3B An example of an imaging system suitable for use in the quality control method described herein is provided, wherein the imaging system is focused on extrudate exiting a side stream die mounted on a main stream die. The imaging system comprises a single camera connected to a computer, a backlight, and a fixture.

[0063] Figure 4 Typical die swells from a slot die (slot as grey beam) as main die or side stream die (element) are shown, wherein the die swell measurements in the width direction for the equilibrium position are represented by the dashed line and the die swell measurements in the height direction for the equilibrium position are represented by the dashed-dotted line.

[0064] Figure 5 One example of an extrudate knife cutting system suitable for use in the quality control methods described herein is shown.

[0065] Figure 6A An embodiment of the quality control method according to the invention is shown, based on recorded images of the extrudate, of macroscopic properties derived from the (die) expansion of the original solid polymer source material inlet flow (one polymer type at a time), in particular the on-line / at-line determination of the extrudate width. Figure 6B One embodiment of a quality control method according to the present invention is shown using on-line / at-line determination of the color spectrum of the extrudate from the raw solid inlet stream determined using color spectrographic methods. Figure 6C An embodiment of the quality control method according to the invention is shown, based on recorded images of the extrudate, macroscopic properties derived from the (die) expansion of the original solid polymer source material inlet flow, in particular the on-line / side-line determination of the extrudate width, said original solid polymer source material inlet flow involving a blend of two polymer types, including also the limiting case of only one such type. Figure 6DAn embodiment of the quality control method according to the invention is shown, based on recorded images of the extrudate, in order to assess the quality of the (die) expansion-derived macroscopic properties of the inlet flow of recycled solid polymer source material (also with reference to the original situation), in particular the on-line / by-line determination of the extrudate width.

[0066] Figure 7 An example of the change in the molecular composition of a copolymer based on methyl methacrylate and ethyl acrylate after heat treatment at 400° C. is provided.

[0067] Figure 8 Shown is a flow chart for obtaining a database relating macroscopic properties of an extruded polymer material to its molecular composition (broken line; calibration) in view of a quality mark or quality control method according to an embodiment of the invention (full line).

[0068] FIG. 9 provides an example of a configuration suitable for performing a quality control method according to one embodiment of the present invention. Figure 9A Shown is a configuration in which solid polymer material is fed to a processing unit having at least one screw and an imaging system comprising 2 cameras each connected to a PC. Figure 9B Shown is a configuration in which solid polymer material is fed to a processing unit having at least one screw, a main flow die and an imaging system comprising 2 cameras each connected to a PC. Figure 9C Shown is a configuration in which solid polymer material is fed to a processing unit having at least one screw, a main stream die and a side stream die and an imaging system comprising a camera connected to a PC. Figure 9D Shown with Figure 9C Compared to a similar imaging system, the imaging system further comprises a backlight arranged to illuminate the xz plane. Figure 9E Shown with Figure 9D Compared to a similar imaging system, the die head is positioned differently, closer to the feed section of the processing unit. DETAILED DESCRIPTION

[0069] Unless the context clearly dictates otherwise, as used herein, the singular forms "a," "an," and "the" include both singular and plural referents. As used herein, the terms "comprising," "comprises," and "comprised of" are synonymous with "including," "includes," or "containing," "contains," and are inclusive or open-ended and do not exclude additional, unrecited members, elements, or method steps. The terms also encompass "consisting of" and "consisting essentially of," which have recognized meanings in patent terminology.

[0070] The recitation of numerical ranges by endpoints includes all numbers and fractions encompassed within the respective ranges, as well as the recited endpoints. This applies to numerical ranges regardless of whether they are introduced by the expression "from to," the expression "between," or another expression.

[0071] As used herein, the terms "about" or "approximately" when referring to measurable values such as parameters, amounts, temporal durations, and the like are intended to encompass variations from and relative to the specified value, such as variations of + / -10% or less, preferably + / -5% or less, more preferably + / -1% or less, and still more preferably + / -0.1% or less from the specified value, and variations of + / -10% or less, preferably + / -5% or less, more preferably + / -1% or less, and still more preferably + / -0.1% or less relative to the specified value, within which such variations are suitable for performing the disclosed invention. It is to be understood that the value to which the modifier "about" or "approximately" refers is itself also specifically and preferably disclosed.

[0072] While the term "one or more" or "at least one" (e.g., one or more members or at least one member of a group of members) is self-explanatory, by way of further illustration, the term specifically encompasses reference to any one of the members, or to any two or more of the members, such as any ≥3, ≥4, ≥5, ≥6, or ≥7 of the members, etc., up to all of the members. In another example, "one or more" or "at least one" may refer to 1, 2, 3, 4, 5, 6, 7, or more.

[0073] The discussion of the background of the invention herein is included to explain the context of the invention. This should not be taken as an admission that any of the material referred to was published, known, or part of the common general knowledge in any country as of the priority date of any claim. Throughout this disclosure, various publications, patents, and published patent specifications are cited by identifying citations. All documents cited in this specification are hereby incorporated by reference in their entirety. In particular, the teachings or portions of such documents specifically mentioned herein are incorporated by reference.

[0074] Unless otherwise defined, all terms (including technical and scientific terms) used in disclosing the present invention have the meanings commonly understood by those skilled in the art to which the present invention belongs. With the help of further guidance, term definitions are included to better understand the teachings of the present invention. Unless otherwise specified, when a particular term is defined in conjunction with a particular aspect of the present invention or a particular embodiment of the present invention, such connotation or meaning is intended to apply throughout this specification, that is, also in the context of other aspects or embodiments of the present invention.

[0075] In the following paragraphs, different aspects or embodiments of the present invention are defined in more detail. Unless explicitly stated otherwise, each aspect or embodiment so defined may be combined with any other aspect or embodiment. In particular, any feature indicated as preferred or advantageous may be combined with any other feature or features indicated as preferred or advantageous.

[0076] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present invention. Therefore, the appearance of the phrases "in one embodiment" or "in an embodiment" in multiple locations throughout this specification does not necessarily refer to (but may refer to) the same embodiment. Furthermore, in one or more embodiments, as will be apparent to those skilled in the art from this disclosure, the particular features, structures, or characteristics may be combined in any suitable manner. Furthermore, although some embodiments described herein include some features and do not include other features included in other embodiments, as will be understood by those skilled in the art, the combination of features of different embodiments is intended to be within the scope of the present invention and to form different embodiments. For example, in the appended claims, any claimed embodiment may be used in any combination.

[0077] According to a first aspect, the present invention relates to a method for quality control of polymer materials. The method preferably comprises the following steps:

[0078] - extruding the polymer source material through an outlet orifice or a die in a processing unit comprising at least one screw; thereby obtaining an extrudate;

[0079] - recording images of the extrudate at different time steps and optionally at different positions using an imaging system;

[0080] - determining at least one expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the recorded images; and,

[0081] - comparing at least one determined expansion-derived macroscopic property of the extrudate with a database of predetermined (ex-die) expansion-derived macroscopic properties of extrudates from polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material.

[0082] In a preferred embodiment, the present invention relates to a method for quality control of polymeric materials. The method preferably comprises the following steps:

[0083] - extruding the polymer source material through an outlet orifice or a die in a processing unit comprising at least one screw; thereby obtaining an extrudate;

[0084] - using an extrudate flow altering device, preferably an extrudate knife cutter system, to temporarily alter the flow of the extrudate;

[0085] - recording images of the extrudate at different time steps and optionally at different positions using an imaging system;

[0086] - determining at least one expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the recorded images; and,

[0087] - comparing at least one determined expansion-derived macroscopic property of the extrudate with a database of predetermined expansion-derived macroscopic properties of extrudates from polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material.

[0088] The present method and its (preferred) embodiments have the advantage that it is material independent: the scheme is material independent and is applicable to virgin materials as well as recycled materials, single component polymers as well as polymer blends. The present method and its (preferred) embodiments have the advantage that it is reproducible: it has been verified in a series of feasibility experiments that similar (de-)swelling patterns occur for similar source materials. The present method and its (preferred) embodiments have the advantage that it is sensitive to expected changes in composition and to microscopic (especially molecular) properties, and that it is robust to experimental errors. The present method and its (preferred) embodiments have the advantage that it can be implemented in an industrial non-invasive manner with online capabilities. The present method and its (preferred) embodiments have the advantage that it is robust to industrial production environments. The present method and its (preferred) embodiments have the advantage that it can be extended with feedback mechanisms that can achieve closed-loop control.

[0089] The term "quality" as used herein with reference to a polymeric source material may refer to one or more desired characteristics of the polymeric material, such as, but not limited to, a desired chemical composition, molecular composition, or raw material composition of the polymeric material.

[0090] In certain embodiments, determining the quality of the polymer source material includes classifying the polymer source material into predetermined polymer quality grades.

[0091] In certain embodiments, determining the quality of the polymeric source material comprises identifying the raw material composition of the polymeric source material.

[0092] "Polymer source material" refers to the polymer material used as source for a processing unit having a screw and whose extrudate is analyzed for quality control. The polymer source material may have been modified during previous processing.

[0093] The polymer source material is preferably a solid polymer material. The solid polymer material can be (i) a granular polymer material or polymer particles; (ii) polymer flakes; (iii) polymer-rich agglomerates; or any combination thereof. Typically, the polymer source material is a blend. Typically, additives are present in the blend. The additives can be active ingredients or chemically modifiable.

[0094] As used herein, the term "granular polymer material" or "polymer particles" refers to particles of polymer material having a size of at least 1 μm and at most several mm. Polymer particles of a smaller particle size range are also known and are referred to herein as "polymer powders". The term "recycled particles" is used to refer to polymer particles of recycled polymer material. (Recycled) particles having a general shape are also referred to as "(recycled) particles", while (recycled) particles having a spherical shape are also referred to as "(recycled) pellets". The term "polymer flakes" refers to flat, granular-sized waste polymer material, for example, resulting from washing, chopping and separation of larger polymer flakes. The term "polymer-rich agglomerates" refers to a waste mixture based on viscous polymers of highly heterogeneous composition and shape.

[0095] The quality control method of the present invention can be used together with original polymer source material and waste polymer source material.Original polymer material or original stream refers to the polymer material that has not yet been used in the product life cycle.Usually, the proportion of pollutants or unqualified polymer materials is very low, for example, less than 1 wt % to 5 wt %.As used herein, " pollutants" refers to the material (for example, metal, soil, paper, etc.) other than the polymer material present in the polymer stream.As used herein, "unqualified polymer material" refers to the polymer material that does not meet the target specification of polymer material.May encounter batch-to-batch (molecule) difference due to the change in aspects such as inlet synthesis composition and reactor conditions (such as temperature gradient such as hot spots, catalyst deactivation and mixing instability).Original polymer material can be made up of a single polymer type, or can be a blend of different polymer types.

[0096] In some preferred embodiments, the polymer source material is a recycled polymer source material and / or a waste polymer source material. In some preferred embodiments, the polymer source material is a recycled polymer source material. In some preferred embodiments, the polymer source material is a waste polymer source material.

[0097] As used herein, the term "recycled" with respect to polymeric source materials refers to one or more polymers, one or more copolymers and / or one or more polymer blends that have been used for a previous purpose and then recovered or regenerated for further processing. The recycled or regenerated material can include post-consumer material, which can be produced after the final consumer has used the material in a consumer product or product and has disposed of the material in a waste stream. The blend can also include virgin material, such as a blend of virgin material and recycled material.

[0098] In other embodiments, polymeric material is the polymeric material of the recovery through sorting.The polymeric material of waste stream or recovery is much more complicated than original stream in composition.In addition, the proportion of pollutant or unqualified polymeric material is usually higher than original material.After suitable sorting, waste stream can be limited by the polymer type of limited total quantity or be made up of the polymer type of limited total quantity, but probably never reach the lower proportion of pollutant or unqualified material in original material.Can be by following definition " polymer type ": the chemical property of the main monomer unit of (i) polymer chain and / or (ii) for taking the topological structure (for example, highly linear relative to highly branched) of the given molecular structure of the skeleton based on its main monomer unit.The advantage that the material through sorting has is that its one or more specific polymer types are more highly concentrated.For example, after suitable sorting, can reclaim the fraction rich in polyolefin (polyethylene / polypropylene), even highly rich in polyethylene fraction or even highly rich in high density polyethylene fraction. Another example is a polymethacrylate-rich stream, which consists of poly(methyl methacrylate) (PMMA) copolymers (made from methyl methacrylate and, for example, ethyl acrylate as monomer units) and PMMA-based composites. Another example is a polystyrene-rich stream. As described elsewhere herein, if the polymer source material is recycled, impurities may also be present in these sorted streams or fractions.

[0099] The polymer source material may be oil-based (as in the above examples) or biopolymer-based, for example comprising polylactic acid or starch polymers. Optionally, the polymer source material may be a key component of a formulation or blend comprising one or more pharmaceutically active ingredients.

[0100] The methods described herein are applicable to any polymer blend. If the pool of polymer source material variants is determined by an acceptable number of polymer types, easier use (e.g., easier calibration) can be achieved. Preferably, a suitable material deformation method is selected to adopt a sufficient amount of extrudate. In some embodiments, the polymer source material is composed of one or more polymer types selected from at least 2, preferably at least 3, and more preferably at least 5 different polymer types. In some embodiments, the polymer source material is composed of one or more polymer types selected from a maximum of 20, preferably a maximum of 10, and more preferably a maximum of 5 different polymer types.

[0101] The polymer source material may also comprise a mixture of soft mixing ingredients and / or active ingredients, in the extreme case a less concentrated polymer solution still being suitable for processing with a processing unit comprising at least one screw.

[0102] The term "extrusion" as used herein refers to a process of bringing a solid polymer material into a molten form, and thus into a liquefied form, so that a change of shape can be achieved. Extrusion of solid polymer material is typically performed in a processing unit comprising at least one screw.

[0103] As used herein, the term "extrusion technology" is intended to refer to any process in which a flowable polymer material (e.g., a molten polymer material) is passed through an outlet orifice or die to impart a desired shape thereto. Non-limiting examples include additive manufacturing or 3D printing technology (e.g., fused deposition modeling and pellet-based material extrusion), tubular film extrusion, sheet extrusion, round rod extrusion, pipe extrusion, profile extrusion, multilayer extrusion, blow molding, wire coating, prepreg molding, injection molding, compounding, pelletizing, or monofilament extrusion.

[0104] As used herein, a "processing unit" refers to a specialized device or machine configured to control the continuous forming of a polymeric material. A processing unit is generally designed to receive raw polymeric source material, subject it to processing conditions (e.g., heat and shear), and extrude it through an exit orifice or die to produce a desired product having a defined shape and size. It should be understood that a processing unit can be designed in a variety of different configurations, all of which are expressly contemplated and form part of this disclosure.

[0105] As used herein, a "reaction unit" refers to a unit in which a reaction is performed to produce, modify, and / or decompose a polymeric material.

[0106] The simplest configuration is a single-screw extruder that is not connected to a die and therefore has only a processing unit outlet hole. When intensive mixing is required, for example for compounding a masterbatch, a twin-screw configuration (also known as twin-screw extrusion) can be used. A further distinction can be made between the counterclockwise and clockwise rotation of the two screws and the distance or intermeshing dimension.

[0107] In a processing unit, different screw elements (eg, positive screw elements or negative screw elements) may define chambers, compartments; thereby defining the screw design, such as a feed compartment, a kneading compartment, and the like.

[0108] The processing unit with a screw preferably also includes a feed section, a melting section, and a metering or pressurizing section. The pressurizing section is preferably connected via a die head where a pressure drop occurs and prepares the molten polymer stream for the outlet. Therefore, in some preferred embodiments, the polymer source material is extruded from the die head. As described elsewhere herein, there are several die head configurations, which depend particularly on the ultimate goal or application of the extruded material after cooling.

[0109] Additional sections may be included in the processing unit, for example for degassing or additional mixing. In case chemicals are added along the processing unit, reactive processing is obtained, such as reactive extrusion or reactive injection molding.

[0110] During the extrusion process, the following parameters can be modified to obtain different die expansions: the rotational speed of the screw; the temperature zones applied to the extruder, for example as can be achieved by a barrel surrounding the screw with possible heating and cooling blocks; contact with cooling streams at or after the main stream die and / or side stream die outlet; the feed load (and type) of the input material stream; and combinations thereof.

[0111] "Die swell" is defined herein as the change in shape of the melt in the x-direction, y-direction and / or z-direction and over time as the melt exits the die, including both expansion and contraction phenomena. The x, y and z directions may be as defined in the accompanying drawings. "Complete die swell" means that an equilibrium setting for all extrudate dimensions has been established. The methods described herein may be based on complete die swell, or on a portion of complete die swell. Optionally, the methods described herein may be based on die swell obtained after a temporary interruption of expansion and / or after removal of at least a portion of the die swell material that has been formed. The amount of material remaining after removal may be subsequently used for rheological analysis in combination with imaging techniques and data analysis. In the extreme case, such removal is almost complete. The amount removed may be source material dependent to facilitate suitable rheological analysis in combination with imaging techniques and data analysis.

[0112] After the extrudate is formed, solidification occurs and a finishing step or a series of finishing steps may be subsequently performed to obtain the final solid product. In some embodiments, the methods described herein further comprise one or more finishing steps to convert the extrudate into the final product. The methods described herein may be supplemented with any finishing steps as known to the skilled person. In a specific embodiment, the extrudate is introduced into a water bath or a pelletizer or a combination of the two, such as in an underwater pelletizer. In some embodiments, the process comprises a continuous finishing step. In some embodiments, the process comprises a discontinuous finishing step. Advantageously, by applying the methods described herein, quality can be determined in situ, thereby allowing optimization of the finishing steps. In fact, the methods as described herein can provide a macro-micro fingerprint of the polymer source material, such that the fingerprint can then be associated with one or more performance parameters.

[0113] For "continuous finishing", the extrudate is continuously produced and finished, such as in pelletizing, sheet production, wire production, and film production. The following provides non-limiting examples including die specifications:

[0114] - A die with multiple outlets is attached to a processing unit with at least one screw. Multiple extrudates leave the die simultaneously, allowing for parallel production of the final product. The extrudates are introduced into a water bath and further into a pelletizer to produce pellets.

[0115] The polymer films can be produced by a blown film extrusion process, wherein an annular die is attached to a processing unit having at least one screw.

[0116] - Polymer sheets can be produced, wherein a slot die is attached to a processing unit having at least one screw.

[0117] - Polymer strands can be produced, wherein a tubular die is attached to a processing unit having at least one screw.

[0118] For "discontinuous finishing," the extrudate is discretely moved / pushed in a predetermined shape, for example, as in injection molding where the extrudate is injected into a cavity defined by a mold, and the final shape is achieved after the mold is cooled and opened.

[0119] In another embodiment, the present invention relates to a kind of polymerizing process of the present invention.Another example of fine processing is the reactive processing that is suitable for the modification (for example, polarity optimization) of little chemical production or polymer, for example, reactive extrusion.Reactive extrusion can also be used to obtain little chemical production, thereby inlet polymer material is converted into oligomer or even monomer completely.The final product can be for coming out from forcing machine and carrying out aftertreatment via for example condenser or flash unit gas or liquid stream.Or, can in forcing machine, still retain the first degradation stage of polymer chain, then for example via further chemical recovery to oligomer or monomer stage in the pyrolysis in another reaction unit.

[0120] Advantageously, the polymer quality control method of the present invention can be integrated into an existing extrusion process for producing polymer products (e.g., polymer films or polymer sheets, polymer pellets, etc.). An imaging system can record an image of the extrudate that is converted into the final product, or a side stream can be separated from the main stream, and the imaging system is arranged to record one or more images of the side stream extrudate. Advantageously, this allows the quality of the polymer material to be adjusted, for example, if the quality of the extruded polymer material is determined to be unsuitable, the quality of the polymer material can be adjusted by adding a known polymer material to the processing unit and / or by changing the operating conditions of the processing unit. Using a side stream has the advantage of being able to obtain a controllable and lower output by the side stream while applying a variable output to the main stream. Using a side stream also has the advantage of being able to obtain a smaller predetermined output by the side stream while applying a much larger output to the main stream. Other advantages of using side stream measurements are, for example, a more practical combination with a flow altering device, a more easily reproducible flow for analysis, a lower impact on processing / recovery, fewer processing steps, less invasive measurements, measurements that can be easily installed, easier maintenance and replacement, and only a smaller hardware kit for quality control is required.

[0121] As used herein, term " die head " refers to (preferably metal) flow restrictor or the passage that can provide predetermined cross-sectional profile for the stream of liquid polymer or melt before leaving extruder.This allows the continuous processing of shapes such as sheet, film, tubing, rod, etc. According to desired product shape, several outlet cross-sectional profiles can be used, such as, but not limited to, square, rectangle, diamond or circle.Other variables of die head include the cross section in die head length, die head and the upstream inlet area (it may change in shape and length) from die head connector to the main part of die head.These variables affect the flow of melt in the channel of die head.For laboratory scale processing, the length of die head can be in the range of 1.0mm to 600.0mm, preferably in the range of 10.0mm to 150.0mm, the width of die head can be in the range of 1.0mm to 300.0mm, preferably in the range of 10.0mm to 150.0mm, and the diameter of die head can be in the range of 0.1mm to 100.0mm, preferably in the range of 0.5mm to 10.0mm. For industrial scale processing, the length of die head can be 100.0mm to 1000.0mm, preferably in the scope of 50.0mm to 500.0mm, the width of die head can be 10.0mm to 3000.0mm, preferably in the scope of 100.0mm to 1000.0mm, and the diameter of die head can be 0.5mm to 30.0mm, preferably in the scope of 1.0mm to 250.0mm.The size of die head is not particularly limited, and can be determined by the finishing step for mainstream.Preferably, the size of lateral stream die head can achieve sufficiently low material flow.After changing die head (size), described method may need to recalibrate.Preferably, die head can be installed at extrudate outlet hole.

[0122] The die head can have an outlet cross-sectional profile or multiple outlet paths, thereby causing several melt profiles or simultaneous outlet flows of the extrudate, such as a so-called pasta die head, which allows the parallel production of desired products. In practice, the die head can be mounted to the processing unit via one or more connecting elements connecting the outlet opening of the processing unit and the die head. The present invention is applicable to any universal die head and / or die head position, such as a die head mounted on a single screw, a double screw or a twin screw, a mixing mill, a blown film unit, etc.

[0123] In some embodiments, the die is a mainstream die. In some preferred embodiments, the die is a side stream die. In some embodiments, the die follows the mainstream direction of the polymer melt (referred to herein as a "mainstream die"). The mainstream die can be placed in a horizontal position along the axis of a processing unit having at least one screw. Alternatively, the mainstream die can be placed in a (partial) vertical position. A non-limiting example thereof is an annular die for, for example, blown film molding. Examples of mainstream dies for laboratory-scale processing that can be used in various embodiments of the present invention can be as follows Figure 1 A shows a horizontal die with a rectangular slot die having a length of 20 mm and a width of 2 mm.

[0124] In some embodiments, the die does not follow the main flow direction of the polymer melt, but follows the direction of a side flow separated from the main flow (referred to herein as a "side flow die"). The angle (θ) of the flow direction of the side flow die relative to the flow direction of the main flow die can be greater than 0 degrees and less than or equal to 90 degrees. An angle (θ) of about 90 degrees can allow for more deformation means based on gravity.

[0125] An advantage of a side stream die as referred to herein is that a portion of the flow of the extrudate can be redirected into a separate stream, optionally wherein the direction of the side stream flow is different from that of the main flow, without the use of any motor or gear pump systems typically required in off-line quality monitoring systems for polymeric materials.

[0126] A non-limiting example of a side stream die used according to one embodiment of the present invention is a vertical die with θ=90°, which is a rectangular slot die with a length of 20 mm and a width of 2 mm, such as Figure 1 As shown in B.

[0127] The side stream die can be mounted to the main stream die (at Figure 9D ) or mounted to a machining unit (in Figure 9E ). Thus, in some embodiments, the side stream die may be mounted before the main stream die to a compartment located closer to the feed section of the processing unit.

[0128] Advantageously, the present invention provides an efficient and cost-effective method for direct and continuous quality monitoring of polymeric materials without interrupting the extrusion process of the polymeric source material. In a preferred embodiment, a side stream extrudate can be separated from the main stream of the extrudate by a side stream die, which allows the quality of the final extruded polymeric material to be determined. In other words, the side stream extrudate can be separated from the main stream extrudate to determine at least one expansion-derived macroscopic property and then optionally returned to the main stream before forming the final polymeric material. This has the advantage that the processing conditions of the main stream extrudate do not necessarily need to be adjusted to determine the quality of the final extruded polymeric material.

[0129] In some embodiments, the extrudate flow from the side stream die is semi-continuous, and more preferably continuous. This has the advantage that the extrudate flow can be analyzed immediately after exiting the side stream die. In some embodiments, the extrudate flow from the side stream die is continuous once it exits the main stream, in the absence of external forces other than gravity, and can be analyzed directly as the extrudate continuously exits the die.

[0130] Due to the viscoelastic properties of the polymer melt, the extrudate from the mainstream die and / or the side stream die demonstrates die expansion. Depending on the cross-sectional profile of the die, the direction of die expansion may be different. For example, the extrudate leaving the slot die may experience expansion in width, height and axial (or mainstream) direction, while the extrudate leaving the circular die may experience expansion in radial and axial directions. The extrudate from the processing unit outlet orifice also demonstrates expansion.

[0131] If the extrudate from the mainstream die is given enough time (in the range of a few seconds) and potential support (e.g., contact with a water bath) is provided to minimize the influence of gravity, equilibrium can be achieved so that the mainstream extrudate no longer expands in any direction. For a lateral flow die, where θ can be greater than 25°, such as about 90°, gravity may affect the expansion of the lateral flow from the die. If enough time is given (in the range of a few seconds), equilibrium can be achieved so that expansion no longer occurs in any direction. This is referred to as the steady state or non-transient state of the outlet flow. The time before reaching equilibrium is defined as a transient state in this article. The transient state can be from 0.001 seconds to 5 seconds, preferably from 0.01 seconds to 5 seconds, more preferably from 0.1 seconds to 5 seconds, such as from 0.1 seconds to 3 seconds.

[0132] In some embodiments, the equilibrium of the extrudate can be affected by physical manipulation of at least a portion of the formed extrudate. Preferably, a portion of the extrudate flow can be disturbed by a flow altering device (e.g., a knife or wire cutter system) that can alter the flow of the extrudate and disturb the expansion equilibrium.

[0133] As used herein, a transient state refers to a period of time during which the extrudate velocity varies as a function of time at at least one location in the x-direction, y-direction, or z-direction. In other words, the state refers to a period of time during which the extrudate does not achieve equilibrium expansion or non-transient behavior.

[0134] In some preferred embodiments, the image is recorded in at least one location in a transient state and / or in a non-transient state. In some preferred embodiments, the image is recorded in a transient state. In some preferred embodiments, the image is recorded in a non-transient state. In some preferred embodiments, the image is recorded in both a transient state and a non-transient state.

[0135] In some embodiments, an image is recorded at a single location. In some embodiments, an image is recorded at more than one location (or at multiple locations).

[0136] In the transient state, the extrudate velocity may vary as a function of time at at least one location in the x, y, and / or z directions, wherein time zero is optionally the time at which the flow modifying device has been applied. Thus, the transient state preferably means that the extrudate has not yet achieved equilibrium expansion or non-transient behavior.

[0137] Depending on the operating conditions of the processing unit with the screw, the potential use of die swell and flow modification devices such as cutter systems, its transient and non-transient states differ. This means that these settings are a means of deformation of the polymer melt under industrially relevant processing conditions involving the screw configuration.

[0138] In some embodiments, at least one (die) expansion-derived characteristic of the extrudate is determined based on the recorded image of the extrudate. These (die) expansion-derived characteristics are macroscopic characteristics that together determine the macroscopic fingerprint of the polymer. Non-limiting examples of (die) expansion-derived characteristics can include extrudate width, extrudate height, expansion surface, expansion ratio, extreme values of one of the aforementioned characteristics, etc. In some embodiments, at least one (die) expansion-derived characteristic is selected from extrudate width, extrudate height or surface area, or extrudate outlet velocity in the z-direction, preferably extrudate width. Methods for determining these (die) expansion-derived characteristics based on recorded images are described elsewhere herein. In some preferred embodiments, one or more (die) expansion-derived characteristics are determined at different times at a specific location (e.g., at 0.5 mm to 10 mm from the side stream die or at 1 mm to 100 mm from the main stream die) (time-dependent analysis). In alternative embodiments, one or more (die) expansion-derived characteristics are determined at different locations at a specific time (position-dependent analysis). The time can be in a transient state or in a non-transient state, preferably in a non-transient state. For example, one can choose a very short time (eg, less than one second) and examine the entire 3D die swell shape, gradually increasing the time in small time steps until the 3D shape reaches equilibrium.

[0139] In some embodiments, changes in the 3D shape or its derived properties can be correlated to changes in process conditions within the processing unit and / or process.

[0140] In some embodiments, the die is a side stream die and at least one expansion-derived macroscopic property of the extrudate is preferably determined at a distance from the side stream die of 0.5 mm to 100.0 mm, or 1.0 mm to 75.0 mm, or 1.0 mm to 70.0 mm, or 1.0 mm to 65.0 mm, or 1.0 mm to 60.0 mm, or 1.0 mm to 55.0 mm, or 1.0 mm to 50.0 mm.

[0141] In some preferred embodiments, the die is a side stream die and the at least one expansion-derived macroscopic property of the extrudate is preferably determined at a distance of 0.5 mm to 10.0 mm, or 1.0 mm to 7.5 mm, or 1.0 mm to 7.0 mm, or 1.0 mm to 6.5 mm, or 1.0 mm to 6.0 mm, or 1.0 mm to 5.5 mm, or 1.0 mm to 5.0 mm from the side stream die.

[0142] In some embodiments, a die as described herein can include one or more die elements. For example, a die can include a first die element and a second die element.

[0143] In some embodiments, a processing unit as described herein may include one or more dies comprising one or more die elements. A non-limiting example includes a processing unit comprising a main stream die and a side stream die comprising: a first side stream die element connected to the main stream die; and a second side stream die element configured to direct the z-direction flow of the side stream extrudate parallel to the z-direction flow of the main stream extrudate.

[0144] For example, using a database, the macro-fingerprint is preferably converted into micro-parameters that indicate the quality of the extruded polymer material (e.g., the average chain length of all relevant overall polymer types). Such micro-parameters can then be converted into performance parameters, such as strength, toughness, water resistance, chemical resistance, etc. The performance parameters can then be converted into application parameters, for example, a given application requires a certain strength, toughness, etc.

[0145] In some preferred embodiments, the method further comprises the following steps:

[0146] - Using an extrudate flow changing device, preferably an extrudate knife cutter system, to temporarily change the flow direction of the extrudate.

[0147] In a more preferred embodiment, the method further comprises the following steps:

[0148] - Using an extrudate flow modifying device, preferably an extrudate knife cutter system, to temporarily modify the flow of the extrudate.

[0149] This step is preferably performed before the step of recording images to obtain images of the transient state. In some embodiments, the images are recorded before temporarily changing the flow direction. In some embodiments, the images are recorded after temporarily changing the flow direction. In some embodiments, the images are recorded before and after temporarily changing the flow direction.

[0150] In some embodiments, the images are recorded before the flow is temporarily altered. In some preferred embodiments, the images are recorded after the flow is temporarily altered. In some embodiments, the images are recorded before and after the flow is temporarily altered.

[0151] As used herein, the extrudate flow-changing device is preferably equipped with a mechanism that allows to change the flow and / or direction of the main stream extrudate and / or the side stream extrudate by mechanical means or thermal means. For example, the extrudate flow-changing device can reduce the flow of the main stream extrudate and / or the side stream extrudate in the x-direction, y-direction and / or z-direction. Optionally, the extrudate flow-changing device can (temporarily) stop the flow of the main stream extrudate and / or the side stream extrudate in the x-direction, y-direction and / or z-direction.

[0152] The knife cutter system preferably comprises a knife cutter. The knife cutter system can be manually operated, resulting in a manual slicer or knife cutter, or can be automatically operated, defining an automatic slicer or knife cutter. In some preferred embodiments, the cutter system performs a physical operation (e.g., cuts the extrudate) with an operating time of 0.01 to 10.0 seconds, preferably 0.01 to 5 seconds.

[0153] Extrudate flow changing device provides the means for polymer material deformation to identify viscoelastic changes.By changing the extrudate flow, a new transient state is produced, until a new equilibrium is reached after a given equilibrium time.Therefore, the extrudate flow changing device can be used to determine the (disembarkation) expansion characteristics of the extrudate under the transient state.At the main stream or side stream extrudate (die head) outlet, the x, y and / or z direction or speed of the extrudate flow can be regulated or changed by the extrudate flow changing device, including temporarily zero speed.The non-limiting examples of the extrudate flow changing device include a knife cutting system, a wire cutting system, a cooled rod and / or a clamping unit.The flow changing device can also be provided with a heating or cooling element.In a preferred embodiment, the flow changing device is a knife cutting system.The knife cutting system and / or the wire cutting system can be easily installed and implemented in a compact manner.

[0154] In some embodiments, the knife cutting system comprises a knife and a blade, wherein the blade comprises steel, copper, or an alloy. In some embodiments, the knife cutting system further comprises a sensor. In some embodiments, the sensor is included so that, with the aid of compressed air, the physical action of the flow altering device can be adjusted in such a way that the blade cuts almost all available extrudates and, in extreme cases, scrapes the die at the die exit cross-section.

[0155] In some embodiments, the cutting position can be variable, and preferably, the cutting position is close to the die exit. In some embodiments, the cutting angle can be variable, and preferably, the cutting angle is parallel to the die zone exit.

[0156] The knife cutting system removes at least a portion of the polymer extrudate at the die exit with a knife, for example, at a fixed time (at Figure 5 ), resulting in transient and non-transient responses due to the viscoelastic properties of the polymer extrudate. Thus, similar to a rheometer in an offline closed setup, the mechanical action of the extrudate flow modification device provides a deformation tool for studying the viscoelastic properties of the polymer melt, albeit (entirely) in the open air and in-line (i.e., during actual processing in a processing unit with at least one screw). Furthermore, by varying the cutting time, the combination of deformation tools can be expanded by exploiting the effects of gravity: the longer the extrudate flows, the greater the influence of gravity.

[0157] In some embodiments, the extrudate flow is varied for about 0.5 seconds to about 20 seconds. In some embodiments, the extrudate flow is repeatedly and temporarily varied (e.g., at least 3 times, e.g., 5 times). Repeated (temporary) variation of the extrudate flow allows for inherent reproducibility checks, which is particularly advantageous for calibration.

[0158] In preferred embodiments, the extrudate flow of the mainstream extrudate and / or the side stream extrudate is varied for about 0.1 seconds to about 30 seconds, or about 0.2 seconds to about 30 seconds, or about 0.3 seconds to about 30 seconds, or about 0.4 seconds to about 30 seconds, or about 0.5 seconds to about 30 seconds, or about 0.5 seconds to about 25 seconds, or about 0.5 seconds to about 20 seconds, or about 1.0 seconds to about 20 seconds, or about 2.0 seconds to about 20 seconds, or about 5.0 seconds to about 15 seconds.

[0159] Another example of a flow modification device may include a cooled rod positioned below the extrudate, for example in a water bath or through a closed water circuit, to direct the flow while supporting the extrudate. Due to the viscoelastic properties of the polymer extrudate, different transient and non-transient responses to cooling and flow directing are obtained.

[0160] Another example of a flow modification device may include a gripper unit that can hold or stretch the polymer extrudate, thereby also changing the transient and non-transient response. Similarly, stretching and therefore rheological changes can be achieved by directing the extrudate to a winding device that winds the extrudate.

[0161] In some embodiments, a flow altering device is placed on the side stream, or its physical action or operation allows adjustment of the extrudate coming out of the side stream die. When used on the side stream, the flow altering device can be used with caution without affecting the mainstream extrudate flow. When used on the mainstream, there is an impact on the extrudate productivity, so it is recommended to use the flow altering device when production is (re)started. In some preferred embodiments, a knife cutting system is used to temporarily change the flow direction of the extrudate from the side stream die. Advantageously, analysis of the side stream extrudate minimizes the impact on the mainstream, and the knife cutting system enables smooth operation and high reproducibility of the side stream die expansion behavior.

[0162] In some embodiments, the extrudate flow altering device further adjusts the x-direction, y-direction, and / or z-direction of the extrudate flow. In some embodiments, the extrudate flow altering device further adjusts the x-speed, y-speed, and / or z-speed of the extrudate flow. The x-direction, y-direction, and z-direction may be as defined in the accompanying drawings.

[0163] In the methods described herein, an optical imaging system is used to obtain Figure 2A) and / or one or more separated side streams ( Figure 2B ) visualization of the extrudate outlet flow.

[0164] In some preferred embodiments, the imaging system comprises one or more cameras, which are optionally connected to a computer comprising a computer processor. In some preferred embodiments, the imaging system comprises one or more backlight sources. In some preferred embodiments, the imaging system comprises a fixture.

[0165] The optical imaging system preferably includes at least one camera optionally connected to a computer (e.g., a personal computer (PC)). Each camera can take continuous images or can realize video imaging of the extrudate flow to characterize it. Each image or video frame is preferably a 2D frame at a given axial position and / or at a given time. As used herein, "axial position" about the extrudate refers to the position on a straight line perpendicular to the middle of the die opening in the extrudate flow. At the high recording frequency of such a frame, a continuous image can be constructed. This allows 3D shape changes when recording a sufficiently wide range of axial positions as a function of time, which makes it possible to identify the most sensitive macroscopic (from the die) expansion derived characteristics. In some embodiments, the image is recorded continuously. In some embodiments, the image is recorded discretely, for example, every 1 millisecond, every 2 milliseconds, every 5 milliseconds, every 10 milliseconds, every 20 milliseconds, every 50 milliseconds, every 100 milliseconds, every 200 milliseconds, every 500 milliseconds, every 1 second, every 2 seconds, every 5 seconds, or every 10 seconds.

[0166] A computer (eg a PC) allows controlling the camera system, storing recorded data and / or processing recorded data.

[0167] The camera system preferably includes at least one camera, and the at least one camera can be positioned toward the extrudate head-on or vertically, visualizing the front and side of the extrudate profile respectively. Multiple camera assemblies can be used to record the image of at least one extrudate from many viewing angles, for example, for visualizing both the front view and the side view of the extrudate simultaneously, allowing 360 ° views of the extrudate to be reconstructed. Multiple cameras can also be used to record images at multiple axial positions to allow construction of a 3D shape. In some embodiments, the image of the extrudate is recorded by two or more cameras, for example, by two, three or four cameras. By using a plurality of cameras, it is possible to better or more widely optically record at least one extrudate, and in particular, for example, from many different viewing angles. This can improve the optical quality control method. Two or more cameras can be arranged toward each other via a fixture.

[0168] In some other embodiments, one or more cameras record images of more than one extrudate, which allows the quality of more than one polymer source material flow to be determined simultaneously.

[0169] The type of camera is not particularly limited. The imaging system can include the same camera or different types of cameras. The cameras may differ, for example, in the type of lens. Cameras that allow color evaluation and / or allow visualization of contaminants (e.g., gel and / or gaseous components) can be used.

[0170] In certain embodiments, the optical imaging system further comprises a backlight source (in Figure 2B ). A backlight is a light source, such as an LED array, placed behind an object to improve visualization and subsequent characterization. The backlight can be a collimated backlight, a non-collimated backlight, or a combination of collimated and non-collimated backlights. A collimated backlight allows for high-precision contour rendering and transmissive applications. With a non-collimated backlight or a standard backlight, the edges of the extrudate may be more contaminated by stray light, resulting in a less distinct contour, but internal contamination or irregularities can be more easily distinguished with this type of light source.

[0171] In certain embodiments, the optical imaging system also includes a fixture. The camera system or the camera system combined with the backlight can be aligned toward each other via the fixture to maintain the relative position of the assembly and / or imaging element within a certain tolerance range. In addition, the complete imaging system is preferably well positioned toward the extrudate to be monitored to ensure the good quality of the image. The fixture composed of the supporting structure that accommodates the camera and the backlight can ensure internal alignment and alignment toward the extrudate. The fixture can be isolated from its surrounding area to obtain optimal light exposure and background control in a production environment.

[0172] Embodiments of the present invention allow for the construction of a modular kit device for quality control that is compatible with a processing unit. Modularity allows for the flexible addition of components to provide means for deformation by mechanical means and / or by temperature change.

[0173] In some preferred embodiments, the method further comprises the following steps:

[0174] - determining at least one second macroscopic property of the extrudate based on the recorded images and / or using a suitable measurement technique.

[0175] The second macroscopic property of the extrudate preferably comprises at least one non-expansion derived macroscopic property, optionally as a function of time and / or position.Preferably, the measurement technique is selected from the group comprising: colorimetry, infrared spectroscopy, laser technology, hyperspectral imaging or a combination thereof.

[0176] At least one second macroscopic property, in particular at least one non-expansion-derived macroscopic property, is preferably also used to determine the quality of the extruded polymer material.

[0177] In some embodiments, the method further comprises the step of determining at least one additional macroscopic property of the extrudate, the additional macroscopic property not being derived from (die) expansion. The additional macroscopic property can be determined based on the recorded image and / or can be determined by a suitable measurement technique. Additional measurement techniques for macroscopic characterization of the extended extrudate may include, but are not limited to, infrared spectroscopy, laser technology, hyperspectral imaging and / or color spectrometry. In a specific embodiment, the method further comprises the step of determining a color spectrum of the extrudate by color spectrometry. The additional non-expansion derived macroscopic property can be determined based on the recorded image, for example, by detecting colored pixels or contrast in the recorded image to identify impurities. For some measurement techniques, the system may be provided with an additional sensor or a set of sensors, which may be positioned in the system by a fixture as described elsewhere herein.

[0178] In the quality control method described herein, at least one macroscopic property of an extrudate of a polymeric source material is determined, in particular at least one (die) expansion-derived macroscopic property and optionally at least one additional non-expansion-derived macroscopic property. A first portion of the macroscopic properties is derived from an imaging system arranged to record one or more images of the extrudate. This portion is in-line if the main (die) extrudate is used during imaging, and is para-line if the side (die) extrudate is used during imaging.

[0179] The recorded images of the transient and / or non-transient (release) expansion in 2D and / or 3D format can be further processed to determine macroscopic properties derived from the (release) expansion, for example by employing principal component analysis or directly calculating the expansion ratio along the x-axis, y-axis or z-axis or the expansion ratio of the expansion area surface defined by the xy plane, xz plane and yz plane relative to the die exit size. The xy plane, xz plane and yz plane can be defined as shown in the accompanying drawings. In certain embodiments, the recorded images are transferred to a computer and a computer program is used to determine or calculate macroscopic properties derived from the (release) expansion of the extrudate.

[0180] The second part of the macroscopic properties, in particular the non-expansion derived macroscopic properties, can be derived from on-line or at-line data recording using further measurement techniques such as infrared spectroscopy, laser technology, hyperspectral imaging and color spectrometry.

[0181] The third part of macroscopic properties, particularly non-expansion derived macroscopic properties, can be derived from additional off-line measurement techniques, for example, of samples from the main die or side die extrudate or solid inlet stream. Exemplary techniques include, but are not limited to, melt flow index (MFI) analysis, differential scanning calorimetry (DSC), and rotational, extensional, and capillary rheometry.

[0182] In some preferred embodiments, the method further comprises the following steps:

[0183] - Off-line determination of at least one macroscopic property, in particular at least one additional non-expansion-derived macroscopic property.

[0184] The at least one macroscopic property determined offline, in particular the at least one additional non-expansion-derived macroscopic property determined offline, is preferably determined on a sample taken from the extrudate or the polymer source material. The at least one macroscopic property determined offline, in particular the at least one additional non-expansion-derived macroscopic property determined offline, is preferably also used to determine the quality of the extruded polymer material.

[0185] The molecular composition of polymeric materials is in many cases not determined by a single polymer type, but rather by a blend. Polymer blends typically contain different overall types of polymers, for example, regranulate from a polyolefin inlet stream may contain (i) polyethylene, both linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and low-density polyethylene (LDPE), (ii) polypropylene, and (iii) additives such as stabilizers and colorants.

[0186] Each polymer population is composed of (macro)molecules that differ in their microscopic composition. For example, the molecules may differ in: the total amount of monomer units (chain length); the type of main comonomer unit (e.g., ethylene vs. propylene units); the fraction of comonomer relative to the total number of chains; the location, length, and number of branching chains; the sequence of (comonomers) per chain; and / or the organization of these molecules in the crystalline or amorphous fraction.

[0187] Molecular composition largely determines the application properties of a polymer type and is therefore a valuable quality marker for the polymer source material. However, the molecular composition of polymers is subject to changes during synthesis, (re)processing, and recycling (e.g., due to varying temperature regimes during manufacturing and product use). In particular, the microscopic characteristics of each individual molecule change during synthesis, (re)processing, and recycling.

[0188] In some preferred embodiments, the method further comprises the following steps:

[0189] - Adjusting the composition of the polymer source material and / or adjusting the operating conditions of the processing unit to achieve an extruded polymer material of the desired quality.

[0190] This step is preferably performed to provide a feedback loop between the step of determining the quality of the extruded polymeric material and the step of extruding the polymeric source material.

[0191] In some preferred embodiments, the method further comprises the following steps:

[0192] - Adjusting the composition of the polymer source material to achieve the desired quality of the extruded polymer material.

[0193] In some preferred embodiments, the method further comprises the following steps:

[0194] - Adjusting the operating conditions of the processing unit to achieve the desired quality of the extruded polymer material.

[0195] Adjusting the operating conditions of the processing unit may include, but is not limited to, adjusting one or more of the barrel temperature profile, screw speed, feed rate, fill ratio, etc. Adjusting the composition of the polymer source material may include, but is not limited to, adding additives, compatibilizers, starting materials, stabilizers, inhibitors, etc.

[0196] In other embodiments, the method may include subjecting the extruded polymeric material to one or more post-processing steps to achieve a desired quality of the polymeric material. Non-limiting examples of post-processing include annealing or coating application.

[0197] According to a second aspect, the present invention relates to a quality control system for polymer source materials. The quality control system is preferably configured to carry out the method according to the first aspect and (preferred) embodiments thereof. The system preferably comprises:

[0198] a processing unit comprising at least one screw and an outlet orifice or die, the processing unit being configured to extrude the polymer source material through the outlet orifice or die;

[0199] - an imaging system configured to record images of the extrudate at different time steps and optionally at different positions; and,

[0200] a computer processor configured to determine at least one (die) swell-derived macroscopic property of the extrudate as a function of time and optionally position based on the recorded images; and to compare the at least one determined (die) swell-derived macroscopic property of the extrudate with a database of predetermined (die) swell-derived macroscopic properties of extrudates from polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material; and,

[0201] - Optionally, extrudate flow modification means, preferably an extrudate knife cutter system.

[0202] In some preferred embodiments, the system includes an extrudate flow altering device, preferably providing a means for material deformation, such as viscoelastic changes. In some preferred embodiments, the system includes one or more cameras, which are optionally connected to a computer comprising a computer processor. In some preferred embodiments, the system includes a backlight or a combination of backlights. In some preferred embodiments, the system includes a fixture. In some embodiments, the system includes one or more sensors associated with a measurement system as described herein.

[0203] According to a third aspect, the present invention relates to a computer-implemented method for quality control of polymer materials. The computer-implemented method preferably comprises the following steps:

[0204] - receiving images from an imaging system, said images being recorded at different time steps and optionally at different positions of an extrudate of a polymer source material passing through an outlet orifice or a die in a processing unit comprising at least one screw;

[0205] - determining at least one expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the received images; and,

[0206] - comparing at least one determined expansion-derived macroscopic property of the extrudate with a database of predetermined (die) expansion-derived macroscopic properties of extrudates from (preferably solid) polymer source materials of known molecular composition to determine the quality of the extruded polymeric material.

[0207] The present invention further relates to a data processing device / device / system comprising means for carrying out the method according to the third aspect and its (preferred) embodiments. The present invention further relates to a data processing device / device / system comprising a processor suitable for carrying out the method according to the third aspect and its (preferred) embodiments. The present invention further relates to a computer program product comprising instructions which, when the program is executed by a computer, causes the computer to carry out the method according to the third aspect and its (preferred) embodiments. The present invention further relates to a computer-readable storage medium comprising instructions which, when executed by a computer, causes the computer to carry out the method according to the third aspect and its (preferred) embodiments.

[0208] In the quality control method of the present invention, the determined macroscopic properties of the extrudate are compared to a database of predetermined expansion-derived macroscopic properties of extrudates from polymer source materials of known molecular composition, which allows identification of the molecular composition of the polymer source material fed to the processing unit.

[0209] Identifying the molecular composition of a polymer source material may include identifying the overall polymer type and / or identifying the presence of additives and / or contaminants.

[0210] According to a fourth aspect, the present invention relates to a method for generating a database relating macroscopic properties of an extruded polymer material to its molecular composition. The method preferably comprises the following steps:

[0211] - extruding a polymer source material of known molecular composition and / or predetermined molecular composition through an outlet orifice or a die in a processing unit comprising at least one screw; thereby obtaining an extrudate;

[0212] - preferably, using an extrudate flow modifying device, preferably an extrudate knife cutter system, to temporarily modify the flow of the extrudate;

[0213] - recording images of the extrudate at different time steps and optionally at different positions using an imaging system;

[0214] - determining at least one expansion-derived macroscopic property and optionally at least one non-expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the recorded images; and,

[0215] - correlating at least one determined expansion-derived macroscopic property and optionally at least one determined non-expansion-derived macroscopic property of the extrudate with a known molecular composition and / or a predetermined molecular composition to generate a database.

[0216] By correlating the determined macroscopic features with the molecular composition of a large source of polymeric materials with known molecular composition, an extensive database of polymeric materials can be obtained that correlates the macroscopic features with their molecular composition.

[0217] In some preferred embodiments, the method further comprises the following steps:

[0218] - determining the molecular composition of the polymer source material or the extruded polymer material via simulations, preferably via kinetic Monte Carlo simulations based on coupling matrices.

[0219] The molecular composition of polymer materials can be tracked via simulations, for example, via coupled matrix-based kinetic Monte Carlo (CMMC) simulations, where each matrix contains microscopic information of a specific part of a single molecule, and its coupling defines the total microscopic information of all parts of all molecules. For a given polymer material with a given chemical modification history, a CMMC simulation can be run to obtain the molecular composition of the polymer material. A beneficial use of CMMC is that information about each molecule and each functional group can be obtained, so that distributed molecular descriptors for microscopic inputs in macro-micro fingerprints can be calculated. Accurate average distribution molecular descriptors can also be calculated, and a very wide range of molecular descriptors can be directly obtained, where the probability that one or a group of molecular descriptors is related to macroscopic properties is significantly high, and a wide range of performance parameters and corresponding correlations can be obtained. Simulations that directly track the (theoretical) average molecule are more approximate and inherently have lower sensitivity to macroscopic changes and performance changes. The advantage of using simulations is that once fine-tuning is achieved both at the chemical and diffusivity levels and at the processing unit or extruder level, they can quickly provide updated molecular descriptors and corresponding averages from the explicitly calculated distributions when applying the most appropriate algorithmic changes. Regarding the process / reactor environment, CMMC, further combined with compartmentalization and convective mass and heat transfer, is applicable to scenarios of mechanical and chemical recycling of polymers and general processing, including the possible presence of activity gradients.

[0220] Alternatively, the molecular composition of the polymeric material may be determined experimentally.Such experimental analysis is preferably performed off-line, for example on a sample of the inlet solid polymeric material, but may also be performed on a sample of the extrudate.

[0221] In some preferred embodiments, the method further comprises the following steps:

[0222] - Determining the molecular composition of the polymer source material or the extruded polymer material via experimental analysis.

[0223] In some preferred embodiments, the database used in the first, second or third aspect of the present invention and its (preferred) embodiments is pre-acquired according to the method of the fourth aspect of the present invention and its (preferred) embodiments.

[0224] Such a database can then be correlated with performance parameters.

[0225] In some embodiments, the quality control method is used to determine the appropriate application of a polymeric material.In some embodiments, the method is used to control a production line for polymeric products (eg, polymer pellets).

[0226] Example

[0227] The aspects and embodiments of the invention disclosed herein are further supported by the following non-limiting examples.

[0228] Example 1: Configuration for quality control of polymer materials according to one embodiment of the present invention

[0229] Figure 1 A schematic diagram of a configuration for quality control of a solid polymer source material according to one embodiment of the present invention is shown. The solid polymer source material (10) is fed to an inlet (110) of a processing unit (120) having at least one screw. The outlet of the processing unit (120) is connected to a die (150) via a connector element (130) having a hole and a connector element (140) having a corresponding opening. One or more images of the extrudate (160) leaving the die (150) are recorded using an imaging system (200) to determine the die swell characteristics of the extrudate. The extrudate (160) can be further processed into a final product in one or more finishing steps (180).

[0230] Example 2: Die suitable for the method of the present invention

[0231] FIG. 2 illustrates a die suitable for use with various embodiments of the present invention. Figure 2A Provided are images of a mainstream die (left) and a mid-section of the same die (right) suitable for use in quality control methods as described herein. Figure 2B Provided are images of a side stream die (left) and a mid-section of the same die (right) suitable for use in the quality control methods as described herein.In both images, a slot die is shown. Figure 2C A diagram is provided of a side stream die comprising a first side stream die element connected to a main stream die and a second side stream die configured for directing a side stream extrudate.

[0232] Example 3: Imaging system suitable for the method of the present invention

[0233] Figure 3AAn imaging system (200) is shown focused on the extrudate (161) exiting the mainstream die (151). The imaging system comprises two cameras (211, 212), each connected to a PC (220). The cameras (211, 212) are arranged to record images of the mainstream extrudate (161) exiting the mainstream die (151) from different viewing angles.

[0234] Figure 3B An imaging system (200) is shown that focuses on an extrudate (162) from a side stream die (152) mounted to a main stream die (151). The flow direction of the side stream extrudate (162) is at an angle (θ) of 90 degrees relative to the flow direction of the main stream extrudate (161). The imaging system (200) includes a camera (211) connected to a PC (220). The camera (211) is arranged to record an image of the xz plane of the side stream extrudate (162) leaving the side stream die (152) and is therefore focused on the xz plane. The imaging system (200) also includes a backlight (230) arranged to illuminate the xz plane. The camera (211) and the backlight (230) are connected via a fixture (240).

[0235] Example 4: Die Swell Direction

[0236] Figure 4 Typical die swell from a slot die is shown, including transient and non-transient states, with measurements of die swell in the width direction for the equilibrium position represented by the dashed line and measurements of die swell in the height direction for the equilibrium position represented by the dashed-dotted line.

[0237] Example 5: Flow changing device suitable for the method of the present invention

[0238] Figure 5 A schematic diagram of an arrangement for carrying out one embodiment of the quality control method of the present invention in which a flow altering device is used is shown. A side stream is separated from a main stream by attaching a side stream die (152) to a main stream die (151). The system is provided with a knife cutting system (171) arranged to cut the side stream extrudate (162). The side stream extrudate (162) can be temporarily cut to produce a transient state for determining the die swell characteristics of the side stream extrudate (162).

[0239] Example 6: Determining Macroscopic Properties of Solid Polymer Materials Using Imaging Systems and / or Other Measurement Techniques

[0240] Figure 6A The figure in FIG shows an example of an imaging system ( Figure 3B) is based on an image of an extrudate of a primary polymer type of a solid polymer material, and the extrudate width is determined as a function of time. After the extrudate is cut using a knife cutting system as described in Example 5, multiple images are recorded at regular intervals. Figure 6A It was shown that different polymer source materials (LDPE-1 grade, LDPE-2 grade, PP, and HDPE) are characterized by different extrudate widths at equilibrium (non-transient state) and that they reach said equilibrium in different ways (transient state). These observed oscillations were found to be reproducible and correlated with the degree of branching of the polymer source material, which allows the assessment of the branching dependence of unknown compositions comprising PE polymer types.

[0241] If Figure 3B The arrangement shown is also provided with a measuring system for performing color spectrometry, so that in addition to determining the expansion-derived macroscopic properties of the solid polymer material as described above, non-(release) expansion-derived macroscopic properties can also be determined, such as Figure 6B Color spectrum of the polymer material shown.

[0242] The combination of expansion-derived macroscopic properties and non-(de-) expansion-derived macroscopic properties (eg, color spectra) may provide a better characterization of the solid polymer source material, and a more accurate determination of the quality of the solid polymer source material.

[0243] Variations in polymer source materials include Figure 6C The figure shows an example of an imaging system ( Figure 3B Recorded images of a blend of two major polymer types of known molecular composition (e.g., a 1000-μm slurry) were taken, and the extrudate width was determined as a function of time, including the limiting case where only one major polymer type of known molecular composition remained. Multiple images were recorded at regular intervals after the extrudate was cut using the knife cutting system described in Example 5. The transition from one polymer type to the other was visible, indicating a shift in microscopic properties (particularly in molecular composition), allowing the creation of a macro-micro fingerprint.

[0244] Another variation of the polymer source material includes Figure 6D The figure shows an example of an imaging system ( Figure 3B ), the extrudate width as a function of time was determined, including the results for a reference case retaining known molecular composition. Multiple images were recorded at regular intervals after the extrudate was cut using a knife cutting system as described in Example 5. The variation in the type of extrudate in the recycled case allows for an assessment of which reference case or combination of reference cases of known composition is representative, which allows for quality control of the recycled polymer source material being analyzed.

[0245] Example 7: Molecular composition of polymer materials

[0246] Figure 7 The evolution of the molecular composition of a copolymer based on methyl methacrylate (MMA) and ethyl acrylate (EA) units at a set temperature of 400°C is shown. Due to degradation, the molar mass (MM) distribution (MMD) of PMMA shifts, and the number of structural defects (e.g., unsaturations) changes. Consequently, different molecular compositions are achieved for different processing and end-of-life histories (e.g., different temperature profiles during manufacturing and / or product use). Furthermore, a sufficient MMD shift has a direct impact on the expansion behavior of the PMMA copolymer.

[0247] Example 8: Generating a database and quality marking polymer materials based on the database

[0248] Figure 8 The dashed line in FIG represents a flow chart for generating a database of polymer source materials, their macroscopic properties, and their molecular composition (calibration phase), which can be used for quality marking of polymer materials according to one embodiment of the quality control method of the present invention. To generate such a database for quality marking, a polymer source material having a known molecular composition (e.g., determined via offline experimental analysis or via simulation using model parameters pre-fitted to a large amount of experimental data) is fed to a processing unit having at least one screw. The molecular composition is correlated with macroscopic features determined by: (i) using an imaging system as described herein, which records images of the extrudate exiting the processing unit having a screw, or preferably exiting a die attached to the processing unit, in transient and / or non-transient states; and optionally (ii) using additional measurement techniques, such as colorimetry, infrared spectroscopy, and / or laser technology, for determining non-die expansion-derived macroscopic features, such as a color spectrum. By correlating the determined macroscopic features, in particular the (die-) expansion-derived macroscopic features and optionally the non-(die-) expansion-derived macroscopic features, with the molecular composition of a large number of polymeric source materials with known molecular composition, a broad database of polymeric source materials correlating macroscopic features with molecular composition is obtained. When a very broad set is determined, a macro-micro fingerprint database is obtained.

[0249] Figure 8The flowchart with a solid line in FIG shows a method for controlling the quality of a solid polymer source material according to one embodiment of the method of the present invention. After obtaining a database that associates macroscopic features of a polymer source material with molecular composition, and therefore after calibration, a processing unit having at least one screw can be adapted to a polymer source material having an unknown molecular composition (e.g., a recycled solid polymer source material). The macroscopic features can be determined by: (i) an imaging system as described herein that records one or more images of the extrudate exiting the processing unit having a screw or preferably exiting a die head mounted to the processing unit in a transient and / or non-transient state; and optionally (ii) using additional measurement techniques, such as colorimetry, infrared spectroscopy, and / or laser technology, for determining non-(die) expansion-derived macroscopic features, such as a color spectrum. The determined macroscopic features, in particular the (die) expansion-derived macroscopic features and optionally the non-(die) expansion-derived macroscopic features, can then be compared with macroscopic features in a pre-constructed database to obtain the molecular composition of the unknown polymer source material. This molecular composition can then be used to determine the quality signature of the final extruded polymer material. In a further stage, the application of the extruded polymeric material can be determined using a database that relates molecular composition to performance parameters at the end-product level.

[0250] Example 9: Configuration applicable to the present invention

[0251] Figure 9A A configuration is shown in which solid polymer material is fed to a processing unit (120) having at least one screw via an inlet stream (110). An imaging system comprising two cameras (211, 212), each connected to a PC (220), is arranged to record images of the extrudate (161) leaving the processing unit (120) from different viewing angles. The absence of a die may limit the straightforward realization of a final product having a desired shape, but this die-less configuration can facilitate the construction (calibration) of a micro-macro fingerprint database.

[0252] Figure 9B A configuration is shown in which a solid polymer source material is fed to a processing unit (120) having at least one screw via an inlet stream (110). An imaging system comprising two cameras (211, 212), each connected to a PC (220), is arranged to record images of an extrudate (161) exiting a die (151) mounted to the processing unit (120) from different viewing angles. The extrudate flow can be temporarily altered (e.g., cut) using an extrudate flow alteration device as described herein. This configuration can be used, for example, to pelletize recycled particles or for mechanical recovery of sheet or wire, and thus for polymer applications. Further details of the configuration are shown in Table 1.

[0253] Table 1

[0254] like Figure 9B Detail of the arrangement shown for quality control of solid polymeric materials.

[0255]

[0256] Figure 9C A configuration is shown in which a solid polymer source material is fed to a processing unit (120) having at least one screw via an inlet stream (110). A main die (151) is connected to the outlet of the processing unit (120). A side stream die (152) is mounted to the main die (151) which separates a side stream extrudate from the main stream. The flow direction of the side stream extrudate (162) is at an angle (θ) of 90 degrees relative to the flow direction of the main stream extrudate (161). An imaging system (200) comprising a camera (211) connected to a PC (220) is arranged to record an image of the xz plane of the side stream extrudate (162) leaving the side stream die (152) and thus focus on the xz plane. This configuration can be used, for example, to pelletize recycled pellets, or for mechanical recycling of sheet or wire (via the main die outlet).

[0257] Figure 9D The configuration shown in Figure 9C , but the imaging system (200) further includes a backlight (230) arranged to illuminate the xz plane. This improves the quality of the recorded image. The camera (211) and the backlight (230) are connected via a fixture (240). The extrudate flow can be temporarily changed (e.g., cut) using an extrudate flow changing device as described herein. This configuration can be used, for example, to granulate recycled particles, or for mechanical recovery of sheet materials or wires (via the main die outlet). More details of the configuration are shown in Table 2.

[0258] Table 2

[0259] like Figure 9D Detail of the arrangement shown for quality control of solid polymeric materials.

[0260]

[0261] Figure 9EA configuration is shown in which a solid polymer source material is fed to a processing unit (120) having at least one screw via an inlet stream (110). A main stream die (151) is connected to the outlet of the processing unit (120). A side stream die (152) is mounted to the processing unit (120) well before the outlet (e.g. near the melting section). An imaging system (200) comprising a camera (211) connected to a PC (220) is arranged to record an image of the xz plane of the side stream extrudate (162) leaving the side stream die (152). The imaging system (200) also comprises a backlight (230) arranged to illuminate the xz plane. The camera (211) and the backlight (230) are connected via a fixture (240). Similar to Figure 9D The configuration shown in the figure but with different side stream die positions can be used for example to use extrusion technology to chemically recycle small chemicals, or for the preheating step comprising the first degradation of polymer chains in a chemical recovery process. This conversion of the side stream die position further upstream not only allows the processing unit for the production of polymer materials comprising recycled materials, but also allows quality control to be provided for the chemical recovery of small molecules. Similarly, it can achieve quality control of polymer modification (that is, reactive processing). Another example (not shown) of the conversion of the side stream die position further upstream is near the degassing unit.

Claims

1. A method for quality control of a polymer material, comprising the following steps: - extruding the polymer source material through an outlet orifice or die in a processing unit comprising at least one screw; thereby obtaining an extrudate; - using an extrudate flow modifying device, preferably an extrudate knife cutter system, to temporarily modify the flow of the extrudate; - recording images of the extrudate at different time steps and optionally at different positions using an imaging system; - determining at least one expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the recorded images; and, - comparing at least one determined expansion-derived macroscopic property of the extrudate with a database of predetermined expansion-derived macroscopic properties of extrudates from polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material.

2. The method of claim 1, wherein the polymer source material is recycled polymer source material and / or waste polymer source material.

3. The method according to any one of claims 1 or 2, wherein the extrudate flow modification device further modulates the x-direction, y-direction and / or z-direction of the flow of the extrudate.

4. The method of any one of claims 1 to 3, wherein the die is a side stream die, and preferably, wherein the at least one expansion-derived macroscopic property of the extrudate is determined at a distance of 0.5 mm to 100.0 mm from the side stream die.

5. The method of any one of claims 1 to 4, wherein the extrudate flow altering device temporarily alters the flow of the extrudate for 0.5 seconds to 20.0 seconds.

6. The method according to any one of claims 1 to 5, wherein the image is recorded in a transient state at at least one position.

7. The method according to any one of claims 1 to 6, further comprising the steps of: - adjusting the composition of the polymer source material, and / or adjusting the operating conditions of the processing unit to achieve an extruded polymer material of a desired quality.

8. The method according to any one of claims 1 to 7, further comprising the steps of: - determining at least one second macroscopic property of the extrudate, in particular at least one non-expansion-derived macroscopic property, optionally as a function of time and / or position, based on the recorded images and / or using suitable measurement techniques; wherein the at least one second macroscopic property, in particular the at least one non-expansion-derived macroscopic property, is also used to determine the quality of the extruded polymer material.

9. The method according to any one of claims 1 to 8, further comprising the steps of: - preferably determining off-line at least one macroscopic property, in particular at least one additional non-expansion-derived macroscopic property, of a sample taken from the extrudate or the polymer source material; wherein the at least one macroscopic property determined off-line, in particular the at least one additional non-expansion-derived macroscopic property determined off-line, is also used for determining the quality of the extruded polymer material.

10. A quality control system for polymer source material, preferably configured to perform the method according to any one of claims 1 to 9, the system comprising: a processing unit comprising at least one screw and an outlet orifice or a die, the processing unit being configured to extrude the polymer source material through the outlet orifice or the die; - an imaging system configured to record images of the extrudate at different time steps and optionally at different positions; a computer processor configured to determine, based on the recorded images, at least one expansion-derived macroproperty of the extrudate as a function of time and, optionally, position; and to compare the at least one determined expansion-derived macroproperty of the extrudate with a database of predetermined expansion-derived macroproperties of extrudates from polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material; and, - Extrudate flow altering means, preferably an extrudate knife cutter system.

11. The method of any one of claims 1 to 9 or the system of claim 10, wherein the imaging system comprises one or more cameras, optionally connected to a computer comprising the computer processor; preferably, wherein the imaging system further comprises one or more backlight sources.

12. A computer-implemented method for quality control of polymer materials according to the method of any one of claims 1 to 9, comprising the following steps: - receiving images from an imaging system, said images being recorded at different time steps and optionally at different positions of an extrudate of a polymer source material passing through an outlet orifice or a die in a processing unit comprising at least one screw; - determining at least one expansion-derived macroscopic property of the extrudate as a function of time and optionally position based on the received images; and, - comparing at least one determined expansion-derived macroscopic property of the extrudate with a database of predetermined expansion-derived macroscopic properties of extrudates from polymeric source materials of known molecular composition to determine the quality of the extruded polymeric material.

13. A method for generating a database relating macroscopic properties of an extruded polymeric material to its molecular composition, the method comprising the steps of: - extruding a polymer source material of known molecular composition and / or predetermined molecular composition through an outlet orifice or a die in a processing unit comprising at least one screw; thereby obtaining an extrudate; - using an extrudate flow modifying device, preferably an extrudate knife cutter system, to temporarily modify the flow of the extrudate; - recording images of the extrudate at different time steps and optionally at different positions using an imaging system; - determining, based on the recorded images, at least one expansion-derived macroscopic property and optionally at least one non-expansion-derived macroscopic property of the extrudate as a function of time and optionally position; as well as, - correlating at least one determined expansion-derived macroscopic property, and optionally at least one determined non-expansion-derived macroscopic property, of said extrudate with a known molecular composition and / or a predetermined molecular composition to generate said database.

14. The method according to claim 13, further comprising the steps of: - determining the molecular composition of the polymer source material or the extruded polymer material via simulations, preferably via coupled matrix based kinetic Monte Carlo simulations.

15. The method according to any one of claims 13 or 14, further comprising the steps of: - determining the molecular composition of the polymer source material or the extruded polymer material via experimental analysis.

Images