Method for recycling a polymer profile

Abstract

The invention relates to a recycling method for a polymer profile (1) for producing a new object (600), wherein: the profile (1) has a core profile (10) comprising the polymer material A; the core profile (10) is provided with a polymer coating (12) comprising a blend of the polymer materials A and B; the coating (12) additionally contains a compatibiliser which improves the bonding of the materials A and B to one another in the blend; the profile (1) comprising the materials A and B and the compatibiliser is comminuted to form a first raw material (1'); a second raw material (200'), which likewise comprises the polymer material B, is used to produce the object (600); the new object (600) is produced using the first raw material (1'), comprising materials A and B and the compatibiliser, and the second raw material (200'), comprising the material B, by means of a polymer melt shaping process (500); and, during the polymer melt shaping process (500) for producing the new object (600), the compatibiliser also contributes to improved bonding of the first raw material (1') to the second raw material (200').

Description

[0001] Recycling process for a polymer profile

[0002] The invention relates to a recycling process for a polymer profile, preferably in the form of a window or door profile having at least one hollow chamber, for producing a new article,

[0003] - wherein the profile has a, preferably fiber-reinforced, core profile with the polymeric material A, and

[0004] - wherein the core profile is provided with a polymeric coating, in particular coextruded with the core profile, comprising a blend of the polymeric materials A and B.

[0005] The sustainable use of resources is one of the greatest challenges of our time. This particularly applies to the recycling of plastic waste. Polymer window and door profiles are characterized by very good thermal insulation properties and are less energy-intensive to produce than, for example, metal profiles. However, when recycling fiber-reinforced plastic profiles in particular, it must be taken into account that the plastic fibers may impair the surface quality of the newly manufactured item using the corresponding recyclate. Fiber-reinforced plastic waste is therefore processed into items for which the surface quality is of secondary importance, for example because the items are installed in such a way that they are not visible during their intended use. This is the case in doors and windows, for example.This is the case with corner connectors, which are inserted into the corresponding hollow chamber profiles at the ends and “disappear” after the profiles have been welded together to form a frame.

[0006] Against this background, the object underlying the invention is to provide a recycling process for plastic waste that fundamentally enables the production of new objects with high surface quality. According to the invention, this object is achieved by a recycling process for a polymer profile, preferably in the form of a window or door profile having at least one hollow chamber, for producing a new object.

[0007] - wherein the profile has a, preferably fiber-reinforced, core profile with the polymeric material A,

[0008] - wherein the core profile is provided with a polymer coating, in particular coextruded with the core profile, comprising a blend of the polymer materials A and B,

[0009] - the coating also contains a phase mediator which improves the bonding of materials A and B in the blend,

[0010] - wherein the profile comprising materials A and B as well as the phase mediator is crushed to a first raw material,

[0011] - wherein a second raw material is used to produce the article, which also comprises the polymeric material B,

[0012] - wherein the new article is produced using the first raw material comprising materials A and B and the phase compatibilizer and the second raw material comprising material B by means of a polymer melt forming process, and

[0013] - wherein the phase compatibilizer also contributes to an improved bonding of the first raw material to the second raw material during the polymer melt forming process for producing the new article.

[0014] According to the invention, the phase mediator already contained in the profile to be recycled also acts as a mediator between the corresponding recyclate – referred to above as the first raw material – and a second raw material when combining these two raw materials, thus expanding the overall design possibilities for the production of the new article. The phase mediator thus enables the production of articles with a high-quality surface, particularly when the first raw material is coated with the second raw material, since this surface is then formed by the coating containing the second raw material, and thus the fibers contained in the first raw material, for example, do not impair the surface of the new article.In this context, the phase compatibilizer already present in the first raw material contributes to the excellent adhesion of the second raw material to the first raw material, which offers significant advantages with regard to the process for producing the novel article. The comminuted first raw material expediently has an average particle size of 1 to 6 mm, in particular 2 to 5 mm. The general inventive concept described above is specified in more detail below.

[0015] According to a preferred embodiment of the invention, the polymer melt shaping process is designed as a coextrusion, in which the second raw material is coextruded with the first raw material and in which the phase compatibilizer ensures interfacial adhesion of the second raw material to the first raw material in the coextrudate. Accordingly, the phase compatibilizer contained in the first raw material also acts according to the invention as an adhesion promoter at the layer boundary between the two components of the coextrudate, wherein one component was produced from the first raw material and the other component from the second raw material. In this embodiment, the new article can be designed in particular as a door or window profile. Preferably, the first raw material is processed into a core extrudate, e.g. having at least one hollow chamber, which core extrudate receives a coating with the second raw material as a result of the coextrusion.In this embodiment, the weight ratio of the first raw material to the second raw material is expediently in the range of 2:1 to 4:1, i.e., for every kg of second raw material, 2 to 4 kg of first raw material are processed in the coextrusion. Within the scope of the invention, it was therefore recognized that the phase compatibilizer, which in itself serves to improve the bonding of the two materials A and B to one another in the blend of the coating of the profile to be recycled and is therefore already contained in the first raw material, simultaneously also leads to improved adhesion at the layer boundary between the two components of the newly produced coextruded article.

[0016] Within the scope of the invention, it is fundamental that in the first raw material the weight ratio of material A to material B is in the range from 2:1 to 4:1, i.e. 1 kg of material B contains 2 to 4 kg of material A. If the polymer profile to be recycled is a hollow chamber profile for a door or window, in which a particularly fiber-reinforced core profile with the polymer material A was coated with a blend of A and B plus phase compatibilizer during coextrusion, such a weight ratio results, for example, from the corresponding cross-sectional ratio of fiber-reinforced core profile and coating, with the reinforcing fibers in the core profile regularly forming the predominant weight proportion in this profile. The production of such a hollow chamber profile is described, for example, in EP 3 529 062 B1.

[0017] The second raw material can consist of recycled material and / or new material. Preferably, the second raw material is free of reinforcing fibers. This is particularly advantageous if, according to the preferred embodiment described above, the first and second raw materials are coextruded and the second raw material, by coating the first raw material, is intended to provide a Class A surface for the new article, which is designed, for example, as a window or door profile. However, the second raw material can also contain reinforcing fibers, particularly if it is also a recycled material. In this context, it can be expedient to apply a further layer, e.g., also by coextrusion, to the coextruded coating containing reinforcing fibers, which is free of reinforcing fibers (and, for example,manufactured with virgin material B), thus ensuring the desired exterior surface of the corresponding article in Class A quality. The second raw material may contain color pigments, e.g., titanium dioxide, to color the new article accordingly.

[0018] The compatibilizer can be present in excess in the coating. This means that the amount of compatibilizer in the blend is greater than is actually required for the desired improved bonding of the two materials A and B to one another in the blend. Such a measure can be advantageous in order to further improve the adhesion of the two components at the layer boundary of the coextruded new article through the compatibilizer. Styrene-maleic anhydride (MAH)-based and / or acrylonitrile-ethylene-styrene (AES)-MAH-based polymers can be used as compatibilizers.

[0019] It is particularly within the scope of the invention that material A is a polyamide (PA). This PA can, for example, be synthesized during production of the core profile by means of reactive pultrusion. Such a reactive pultrusion process is also described, for example, in EP 3 529 062 B1. In this process, continuous reinforcing fibers are drawn into a pultrusion tool and embedded in a PA matrix therein. For this purpose, low-viscosity monomers or oligomers are used, which react during the reactive pultrusion to form the thermoplastic polyamide. The core profile is then provided with a coating, for example a coextruded coating, which comprises the blend of materials A and B.

[0020] Material B can in particular be an acrylonitrile-styrene-acrylate (ASA). The weight ratio of materials A to B in the blend is expediently 1:2 to 2:1, i.e. 1 kg of material B contains 0.5 kg to 2 kg of material A. The profile to be recycled can therefore in particular be a continuous fiber-reinforced window or door profile produced according to EP 3 529 062 B1, which contains continuous fiber-reinforced PA as the core material and is then provided according to the invention with a coating made of a blend of PA and ASA, whereby the profile has the required weathering stability and, surprisingly, at the same time the recycling of this profile is considerably facilitated. In this case, the continuous fiber-reinforced core material is processed by comminution to form a first raw material which then contains correspondingly short fibers.It is also within the scope of the invention that material B is an acrylonitrile butadiene styrene (ABS).

[0021] As already explained, according to a particularly preferred embodiment of the invention, the core profile can have continuous fiber reinforcement and be manufactured by reactive pultrusion. Such profiles are characterized by outstanding mechanical properties. The weight fraction of continuous fibers in the core profile can be in the range of 60 to 90%, for example, 75 to 85%. Using the recycling process according to the invention, waste from corresponding window or door profiles can be easily recycled and processed into new, high-quality articles, as already described above.

[0022] The profile to be recycled, in particular its core profile made from the first raw material, expediently has at least two hollow chambers. The coating of the core profile made from the second raw material preferably consists of an unreinforced material to ensure a flawless outer surface. However, this does not preclude the inclusion of reinforcement, e.g., in the form of reinforcing fibers, in the coating. The hollow chamber profile to be recycled in the form of a window or door profile can, in particular, be a blind or sash frame profile.The invention further relates to a polymeric profile, in particular in the form of a window or door profile having at least one hollow chamber, suitable for use in a recycling process according to the invention, with a core profile which has a, preferably endless fiber-reinforced, PA matrix, and a coating applied to the core profile, preferably coextruded with the core profile, which coating has a polymer matrix made of a PA-ASA blend.

[0023] - the coating also contains a phase mediator that improves the bonding of the PA and ASA materials in the blend.

[0024] An object produced by means of a recycling process according to the invention as described above is also to be protected.

[0025] The invention is explained in detail below with reference to a drawing that represents only one exemplary embodiment. The drawings schematically show:

[0026] Fig. 1 shows a method for producing a hollow chamber window profile which, for example, is to be subjected to the recycling process according to the invention at the end of its life cycle;

[0027] Fig. 2 shows a hollow chamber profile produced according to Fig. 1 in a cross-sectional view and

[0028] Fig. 3 shows a recycling process according to the invention, for example for the hollow chamber profile shown in Fig. 2

[0029] Fig. 1 shows a method for producing a thermoplastic hollow chamber window profile 1, which is shown in cross-section in Fig. 2. The hollow chamber window profile 1 is to be fed into a recycling process according to the invention, for example at the end of its intended use as a component of a window. Furthermore, production-related waste, which arises, for example, during cutting and in particular from miter cuts for assembling the profiles 1 to form a frame, can also be recycled in this way. In the production process shown in Fig. 1, the hollow chamber profile 1 having a plurality of hollow chambers 2 (cf. Fig. 2) is produced using a strand production process 3. During this strand production process 3, continuous reinforcing glass fibers 5 are integrated into the thermoplastic matrix 4 of the hollow chamber profile 1. These fibers are first drawn off from rolls 6 and preheated in a preheating station 7.In the exemplary embodiment, the strand production process 3 is designed as reactive pultrusion. Here, the freshly produced hollow chamber profile 1 is drawn out of the heated pultrusion tool 9 via the continuous reinforcing fibers 5 in the production direction x by means of a drawing tool 8. The reactive pultrusion 3 serves to produce a continuously fiber-reinforced thermoplastic core profile 10 (see also Fig. 2, colored black) of the hollow chamber profile 1, which has a plurality of hollow chambers 2. The thermoplastic matrix 4 of this core profile is produced from low-viscosity monomers and / or reactive oligomers - both designated MO - which are polymerized to form the thermoplastic during the reactive pultrusion 3. In addition to the monomers and / or reactive oligomers MO, initiators I and catalysts K are added to the reactive pultrusion 3 to guide the chemical reaction taking place therein.In the exemplary embodiment, the monomers or oligomers designated MO are fed to the reactive pultrusion in two components a' and b' for the polymerization of the thermoplastic. Component a' contains monomers / oligomers MO and initiators I, while component b' contains catalysts K in addition to the monomers / oligomers MO. This ensures that a reaction mixture containing monomers / oligomers MO as well as initiators I and catalysts K is only present in the pultrusion tool 9 and thus the polymerization is only started in the pultrusion tool 9. The polymerization rate can also be controlled by heating the pultrusion tool 9. In the exemplary embodiment, the thermoplastic matrix 4 is designed as a PA matrix, in particular as a PA6 matrix.In order to improve the surface quality of the hollow chamber profile 1, the core profile 10 produced by reactive pultrusion 3 is provided with an outer polymer coating 12 by means of coextrusion 11. In the exemplary embodiment, this outer polymer coating 12 consists of a blend of PA and ASA, whereby the weight ratio of PA to ASA in this blend is in the range 0.8 to 1.2 (1.2 means 1.2 kg PA per kg ASA). In the exemplary embodiment according to Fig. 1, the coextrusion 11 takes place immediately after the reactive pultrusion 3. In this case, the coextrusion tool 13 is arranged immediately behind the outlet of the tool 9 for the reactive pultrusion 3 and encases the core profile 10 online. Only then is the coextruded hollow chamber profile 1 cooled in a cooling device 14, e.g. a water bath. Alternatively, the reactive pultrusion 3 and the coextrusion 11 can also be carried out, for example, in a common tool.An extruder 16 is provided for applying the coating 12, which consists of coating material 15.

[0030] Fig. 2 shows a window hollow chamber profile 1 which can be produced, for example, using the method described in Fig. 1. The enlarged section of Fig. 2 schematically shows the continuous reinforcing fibers 5 embedded in the thermoplastic PA matrix 4 of the core profile 10, as well as the coating 12, shown here exaggeratedly thick, coextruded with the core profile 10 and made of unreinforced coating material 15 which consists of a PA-ASA blend. In the exemplary embodiment, the weight proportion of the reinforcing fibers 5 in the core profile 10 is 75 to 85%, the remainder PA, and the weight ratio of PA in the core profile 10 to the PA-ASA blend in the coating is 0.8:1 to 1:1. Overall, the weight ratio of PA to ASA is in the range from 2:1 to 4:1. The hollow chamber profile 1 further comprises functional elements 18, 18' in the form of receiving grooves for sealing or locking elements (not shown). In Fig.2, the window hollow chamber profile 1 is designed as a sash frame profile. Accordingly, the core profile 10 has a rebate base 19 for receiving at least one (not shown) glass pane. The coating 12 is applied almost completely to the outer surface of the core profile 10. Only the groove base of the right-hand receiving groove 18' is formed solely by the core profile 10. Furthermore, only the coating 12 forms projections 20 of a Euro groove 21 of the hollow chamber profile 1 for receiving locking elements (not shown). To optimize the bonding of the ASA to the PA in the blend, the blend additionally contains a phase compatibilizer (not shown in detail in the figures) in the form of styrene-maleic anhydride (MAH)-based and / or acrylonitrile-ethylene-styrene (AES)-MAH-based polymers. The weight fraction of the phase compatibilizer in the blend is 0.5 to 10% in the exemplary embodiment, for example 1 to 8%, e.g.2 to 4%, although other weight proportions are of course not excluded.

[0031] Fig. 3 shows a recycling process according to the invention for a polymeric hollow chamber profile 1 in the form of a window or door profile, as shown, for example, in Fig. 2. The hollow chamber profile 1 accordingly has a continuously fiber-reinforced core profile 10, the polymer of which consists of the material PA. The core profile 10 is provided with a polymer coating 12 made of a PA-ASA blend 15, which additionally contains the previously described phase compatibilizer. In the recycling process according to Fig. 3, the hollow chamber profile 1 comprising the materials PA and, in the blend, PA-ASA as well as the phase compatibilizer (e.g. in the form of cut-off end pieces or miter waste which arise during the manufacture of a frame composed of hollow chamber profiles 1 or, in particular, during complete recycling at the end of the useful life of the hollow chamber profile 1) is shredded in a shredding device 100 (e.g. a plastic shredder).The average particle size of the comminuted first raw material T is in the range of 2 to 5 mm and due to the continuous fibers 5 comminuted in the comminution device 100, this raw material T contains corresponding short fibers (not shown in detail).

[0032] To produce a new article 600 using the first raw material T, a second raw material 200' is additionally used, which also comprises the material ASA. The new article 600 is thus produced using the first raw material T, which comprises the materials PA and ASA, as well as the phase compatibilizer (and comminuted reinforcing fibers), and the second raw material, which comprises the material ASA, by means of a polymer melt forming process 500. According to the invention, the phase compatibilizer also contributes to an improved bond between the first raw material T and the second raw material 200' during the polymer melt forming process 500 for producing the new article 600.In the exemplary embodiment, the polymer melt forming process 500 is designed as a coextrusion, in which the second raw material 200' is coextruded with the first raw material T, and the compatibilizer contained in the first raw material T ensures adhesion of the two coextruded components to one another. In the exemplary embodiment, the raw material 200' is virgin material in the form of granulated ASA. The second raw material 200' further contains color pigments, e.g., titanium dioxide, in order to color the new article 600 accordingly. Overall, the compatibilizer contained in the first raw material T acts as an adhesion promoter in the newly produced article 600 at the phase boundary between the two coextruded components 10', 15', wherein one component 10' produced from the first raw material T comprises PA and ASA, and the other component 15' produced from the second raw material 200' comprises ASA with added color pigments.In the exemplary embodiment, the new article 600 is designed as a coextruded door or window profile. As can be seen from Fig. 3, the first raw material T is processed into a core extrudate 10' having a plurality of hollow chambers, which core extrudate receives a coating 15' with the second raw material 200' as a result of the coextrusion. The weight ratio of the first raw material T to the second raw material 200' is in the range from 2:1 to 4:1, i.e., for every kg of second raw material 200', 2 to 4 kg of first raw material T are processed in the coextrusion. According to the invention, the compatibilizer contained in the PA-ASA blend ensures adhesion of the coating 15' to the core extrudate 10' over the entire aforementioned weight proportions. Since the first raw material 1' was obtained from the shredded continuous fiber-reinforced hollow chamber profile 1, the core extrudate 10' contains correspondingly shredded short fibers (not shown in detail), while the coating.

[0033] 15' is made of virgin ASA material, which is free of reinforcing fibers and thus enables the provision of a Class A surface of the newly manufactured hollow chamber profile 600.

[0034] Patent claims

Claims

Patent claims 1. Recycling process for a polymeric profile (1), preferably in the form of a window or door profile having at least one hollow chamber (2), for producing a new article (600), - wherein the profile (1) has a preferably fiber-reinforced core profile (10) with the polymeric material A, - wherein the core profile (10) is provided with a polymer coating (12), in particular coextruded with the core profile (10), comprising a blend of the polymer materials A and B, - wherein the coating (12) additionally contains a phase mediator which improves the bonding of materials A and B in the blend, - where the profile comprising materials A and B and the phase mediator (1) is crushed into a first raw material (T), - wherein a second raw material (200') is used to produce the article (600), which also comprises the polymeric material B, - wherein the new article (600) is produced using the first raw material (T) comprising the materials A and B and the phase compatibilizer and the second raw material (200') comprising the material B by means of a polymer melt forming process (500), and - wherein the phase compatibilizer also contributes to an improved bonding of the first raw material (T) to the second raw material (200') during the polymer melt forming process (500) for producing the new article (600).

2. Method according to claim 1, characterized in that the polymer melt forming process (500) is designed as a coextrusion, in which the second raw material (200') is coextruded with the first raw material (T) and in which the Phase compatibilizer ensures interfacial adhesion of the second raw material (200') to the first raw material (T) in the coextrudate.

3. Method according to claim 2, characterized in that the new article (600) is designed as a door or window profile and in this case the first raw material (T) is preferably processed into a core extrudate (10') which receives a coating (15) with the second raw material (200') by the coextrusion.

4. Method according to one of claims 1 to 3, characterized in that the weight ratio of the first raw material (T) to the second raw material (200') is in the range of 2:1 to 4:

1.

5. Method according to one of claims 1 to 4, characterized in that in the first raw material (T) the weight ratio of material A to material B is in the range from 2:1 to 4:

1.

6. Method according to one of claims 1 to 5, characterized in that the second raw material (200') consists of new material and is preferably free of reinforcing fibers.

7. Process according to one of claims 1 to 6, characterized in that the phase compatibilizer is present in excess in the coating.

8. Process according to one of claims 1 to 7, characterized in that styrene-maleic anhydride (MAH)-based and / or acrylonitrile-ethylene-styrene (AES)-MAH-based polymers are used as phase mediators.

9. Method according to one of claims 1 to 8, characterized in that the material A is a polyamide (PA).

10. Process according to one of claims 1 to 9, characterized in that the material B is an acrylonitrile-styrene-acrylate (ASA).

11. Process according to one of claims 1 to 9, characterized in that the weight ratio of materials A and B in the blend is 1:2 to 2:

1.

12. Method according to one of claims 1 to 11, characterized in that the core profile (10) has an endless fiber reinforcement (5) and is manufactured by means of reactive pultrusion (3).

13. Polymer profile (1), in particular in the form of a window or door profile having at least one hollow chamber (2), suitable for use in a recycling process according to one of claims 1 to 12, with a core profile (10) which has a, preferably endless fiber-reinforced, PA matrix and a coating (12) applied to the core profile (10), preferably coextruded with the core profile (10), which has a polymer matrix (15) made of a PA-ASA blend, - wherein the coating (12) additionally contains a phase mediator which improves the bonding of the materials PA and ASA in the blend.

14. An article (600) produced by a recycling process according to any one of claims 1 to 13.