Method for recycling a polymer profile

Abstract

The invention relates to a method for recycling a polymer profile (1), preferably in the form of a window or door profile having at least one hollow chamber (2), in order to produce a new object (600), wherein: the profile (1) is a preferably fibre-reinforced core profile (10) having the polymer material A; the core profile (10) is provided with a polymer coating (12) having the polymer material B, which coating is in particular coextruded with the core profile (10); the profile (1) comprising materials A and B being comminuted to form a first raw material (1'); a second raw material (200'), which comprises the polymer material C that is incompatible with the material A, is used to produce the object (600); the new object (600) is produced by means of a polymer melt forming process (500) using the first raw material (1'), which comprises the materials A and B, and the second raw material (200'), which comprises the material C; and, during the production of the new object (600), the material B acts as a compatibiliser and / or adhesion promoter between the incompatible materials A and C.

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 containing the polymeric material B, in particular coextruded with the core profile.

[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 excellent thermal insulation properties and, for example, are less energy-intensive to produce than metal profiles. When recycling plastics, for example, a common challenge is that different types of plastic are generated and need to be fed into a common recycling process. One issue that is often relevant in this context is the so-called incompatibility of different types of plastic.Incompatibility here means that a corresponding mixture of different plastic types cannot easily be produced during processing into a new product, in which the individual plastics are present in a molecularly distributed or microscopically dispersed plastic alloy in the polymer matrix of the new product. Instead, the individual plastics decompose into two or more phases. This is generally undesirable, as it impairs the product properties.

[0006] Against this background, the object underlying the invention is to provide a recycling process for plastic waste that ensures improved compatibility of the polymeric materials generated as waste. According to the invention, this object is achieved by a recycling process for a polymeric profile, preferably in the form of a window or door profile having at least one hollow chamber, for producing a new article.

[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 polymeric coating containing the polymeric material B, in particular coextruded with the core profile,

[0009] - wherein the profile comprising materials A and B is crushed into a first raw material,

[0010] - wherein a second raw material is used to manufacture the article, which comprises the polymeric material C which is incompatible with the material A,

[0011] - wherein the new article is produced using the first raw material comprising materials A and B and the second raw material comprising material C by means of a polymer melt forming process, and wherein, in the production of the new article, material B acts as a phase and / or adhesion promoter between the incompatible materials A and C.

[0012] According to the invention, the coating material B of the profile to be recycled acts as a phase or adhesion promoter between the inherently incompatible plastic types A and C and ensures that the plastics A and C can be processed together to form a new article. The polymer melt forming process for producing the new article can, in particular, be an extrusion or injection molding process, although this does not preclude other processes, such as blow molding or 3D printing. The comminuted first raw material expediently has an average particle size of 1 to 6 mm, in particular 2 to 5 mm.According to one embodiment of the invention, the polymer melt forming process is designed as a coextrusion, in which the second raw material is coextruded with the first raw material and the material B ensures adhesion of the two coextruded layers to one another. Accordingly, the material B acts here as an adhesion promoter at the layer boundary of the two components of the coextrudate, with one component comprising material A and the other component comprising material C, which is incompatible with material A. 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 from 2:1 to 4:1, i.e. in this case, 2 to 4 kg of first raw material are processed in the coextrusion per kg of second raw material.

[0013] In a further embodiment of the invention, the first raw material is first mixed with the second raw material and, in the mixed state, fed to the polymer melt shaping process. Preferably, the adhesion-promoting effect of material B results in the polymer matrix of the new article being present as a homogeneous polymer blend. In this case, the new article is expediently designed as an injection-molded corner connector or as an extruded thermal release profile for door or window profiles, although this does not, of course, preclude processing into a different article. The weight ratio of the first raw material to the second raw material in this case is, for example, more than 5:1 and is preferably in the range from 10:1 to 30:1, in particular 10:1 to 20:1, i.e. at least 5 kg of first raw material are processed for each kg of second raw material.

[0014] 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 of 1:2 to 2:1, ie for every 1 kg of material B there are 0.5 to 2 kg of material B. In particular, the weight ratio A / B can be in the range of 0.8: 1 to 1: 1.

[0015] If the polymer profile to be recycled is a hollow chamber profile for a door or window, in which a fiber-reinforced core profile made of material A has been coextruded with a coating made of material B, such a weight ratio is naturally derived, for example, from the corresponding cross-sectional ratio of the fiber-reinforced core profile and the coating, with the reinforcing fibers in the core profile generally constituting the predominant weight fraction of this profile. The production of such a hollow chamber profile is described, for example, in EP 3 529 062 B1.

[0016] The second raw material can consist of recycled material and / or virgin material. The second raw material is preferably free of reinforcing fibers. This is particularly advantageous if, according to the first 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. This further layer is free of reinforcing fibers (e.g., made from virgin PVC), thus ensuring the desired outer surface of the corresponding article in Class A quality.The second raw material may contain color pigments to color the new item accordingly.

[0017] It is particularly within the scope of the invention that material A is a polyamide (PA). This PA can, for example, be synthesized during the 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, e.g. a coextruded coating, which comprises material B.

[0018] Material B can in particular be a blend of materials A and a polymeric material D. In the case of coextrusion, e.g. according to EP 3 529 062 B1, material D contained in the coating acts as a phase or adhesion promoter between materials A and C during recycling of the correspondingly manufactured profile, whereby material A of the core material (e.g. the aforementioned PA) is also contained as a component in the coating. Material D can in particular be an acrylonitrile-styrene-acrylate (ASA). The weight ratio of materials A to D in the blend is expediently 1:2 to 2:1, i.e. 0.5 kg to 2 kg of material A are used for every 1 kg of material D.The profile to be recycled can therefore be, in particular, a continuous fiber-reinforced window or door profile manufactured 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 weather resistance and, surprisingly, at the same time, significantly facilitates the recycling of this profile. In this case, the continuous fiber-reinforced core material is processed by comminution into a first raw material, which then contains correspondingly short fibers.

[0019] Material C is advantageously PVC. Due to its outstanding properties with regard to weather resistance, PVC is still the most frequently used polymer for the production of plastic window or door profiles. With reference to the aforementioned preferred embodiments for the other recycling materials, ASA in particular is able to act as a phase mediator for the incompatible plastics PA and PVC. This makes it possible, in particular, to completely recycle corresponding window or door profiles, which are produced, for example, using a reactive pultrusion process according to EP 3 529 062 B1, in which, for example, PVC waste is also to be reused. For example,When the recycled PA material and a blend of PA and ASA are mixed with PVC prior to processing into a new article, the phase-mediating effect of ASA results in a homogeneous polymer matrix in the new article, even though PA and PVC are inherently incompatible and would therefore decompose into two phases if processed together. Furthermore, when the above-described recycled PA material and PA / ASA material are coextruded with PVC, the adhesion-promoting effect of ASA ensures good adhesion between the two components of the coextrudate containing PA on the one hand and PVC on the other, so that the article produced accordingly has very good product properties.This coextrudate can then accordingly have a core reinforced with short fibers containing PA and ASA, which is preferably coated with unreinforced PVC to ensure a flawless appearance of the new article, in particular a window or door profile. 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 the 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.

[0020] The profile to be recycled, particularly its core profile, expediently has at least two hollow chambers. The coating of the core profile is preferably made 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.

[0021] 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 PA matrix, preferably a continuous fiber-reinforced one, and a coating applied to the core profile, preferably coextruded with the core profile, which has a polymer matrix made of a PA-ASA blend.

[0022] An object produced by means of a recycling process according to the invention as described above is also to be protected.

[0023] The invention is explained in detail below with reference to a drawing that represents only one exemplary embodiment. The drawings schematically show: 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;

[0024] Fig. 2 shows a hollow chamber profile manufactured according to Fig. 1 in a cross-sectional view

[0025] Fig. 3 shows a recycling process according to the invention, for example for the hollow chamber profile shown in Fig. 2

[0026] Fig. 4 shows an alternative recycling process according to the invention, for example for the hollow chamber profile shown in Fig. 2

[0027] 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 polymerizing 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 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.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, which in the exemplary embodiment consists of a blend of PA and ASA, wherein 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.

[0028] 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. 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 here has a rebate base 19 for accommodating at least one (not shown) glass pane. The coating 12 is applied almost entirely 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 accommodating locking elements (not shown). To optimize the bonding of the ASA to the PA in the blend, the blend can additionally contain styrene-maleic anhydride (MAH)-based and / or acrylonitrile-ethylene-styrene (AES)-MAH-based polymers.

[0029] Figs. 3 and 4 schematically show two different recycling processes 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 continuous fiber-reinforced core profile 10, the polymer of which consists of the material PA. The core profile 10 is provided with a polymeric coating 12 made of a PA-ASA blend 15.

[0030] In the recycling process according to Fig. 3, the hollow chamber profile 1 comprising the materials PA and PA-ASA (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) and, as shredded first raw material T, is then initially mixed with a second raw material 200'. According to Fig. 3, the second raw material is shredded recyclate 200' which comprises the polymer material PVC and was obtained, for example, from a fiber-reinforced PVC hollow chamber profile 200 for a door or window and shredded in a shredding device 100'. The PVC hollow chamber profile 200 used can, however, also be free of reinforcing fibers.The comminution of the hollow chamber profile 1 comprising the materials PA and ASA can - as shown in Fig. 3 - take place separately from the comminution of the PVC waste 200 in two separate comminution devices 100, 100', or alternatively as part of a joint comminution process, e.g. jointly in the comminution device 100 or 100'. The separate comminution of the PVC waste 200 shown in Fig. 3 can take place spatially and / or temporally separated from the comminution of the hollow chamber profile 1. The average particle size of the 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).In the separate comminution shown in Figure 3, the already comminuted waste batches T, 200' are expediently mixed in a mixer 300 to form the comminuted total recyclate 20. In the total recyclate 20, the weight ratio of the first raw material 1' to the second raw material 200' is in the range of 10:1 to 20:1, ie, 10 to 20 kg of first raw material are used per kg of second raw material.

[0031] The shredded total recyclate 20 comprising the materials PA, PA-ASA, and PVC is then fed into the actual recycling process, where a new article 600 is produced from the total recyclate 20 by means of a polymer melt forming process 500, for example, an extrusion or injection molding process. According to the invention, the ASA polymer contained in the PA-ASA blend in the total recyclate 20 creates compatibility between the incompatible materials PA and PVC across the entire aforementioned weight proportions, such that the polymer matrix of the new article is present as a homogeneous polymer blend. The new article can be, for example, an extruded separating profile for a window or door profile or a corner connector for such profiles.Since the first raw material T was obtained from the crushed continuous fiber-reinforced hollow chamber profile 1, the article 600 contains correspondingly crushed short fibers (not shown in detail) distributed homogeneously over its cross section.

[0032] According to the embodiment of the invention shown in Fig. 4, 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 material B ensures adhesion of the two coextruded layers to one another. The first raw material T can in turn be a shredded recyclate obtained from the previously described hollow chamber profile 1. In the embodiment according to Fig. 4, the raw material 200' is virgin material in the form of granulated PVC. The second raw material 200' also contains color pigments, e.g. titanium dioxide, in order to color the new article accordingly. Accordingly, the ASA contained in the first raw material T acts as an adhesion promoter at the phase boundary between the two components of the coextrudate, one component comprising PA and the other component comprising PVC, which is incompatible with the material PA.In this embodiment, the new article 600 can in particular be designed as an extruded door or window profile. Preferably, the first raw material T is processed into a core extrudate 10', for example having at least one hollow chamber, which core extrudate 10' receives a coating 15' with the second raw material 200' through the coextrusion. The weight ratio of the first raw material 1' to the second raw material 200' in this embodiment is expediently in the range from 2:1 to 4:1, i.e. in this case, 2 to 4 kg of first raw material T are processed in the coextrusion per kg of second raw material 200'. According to the invention, the ASA polymer contained in the PA-ASA blend creates compatibility between the incompatible materials PA and PVC over the entire aforementioned weight proportions in such a way that the two coextruded components 10' and 15' adhere to one another.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 15' consists of virgin PVC that is free of reinforcing fibers and thus enables the provision of a Class A surface of the new article 600.

[0033] 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 polymeric coating (12) containing the polymeric material B, in particular coextruded with the core profile (10), - wherein the profile (1) comprising the materials A and B is crushed into a first raw material (T), - wherein a second raw material (200') is used to produce the article (600), which comprises the polymeric material C which is incompatible with the material A, - wherein the new article (600) is produced using the first raw material (T) comprising the materials A and B and the second raw material (200') comprising the material C by means of a polymer melt forming process (500), and - wherein, during the manufacture of the new article (600), material B acts as a phase and / or adhesion promoter between the incompatible materials A and C.

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 this case the material B ensures adhesion of the two coextruded layers (10', 15') to one another.

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 claim 2 or 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 claim 1, characterized in that the first raw material (T) is first mixed with the second raw material (200') and is fed in the mixed state to the polymer melt forming process (500), and that preferably the adhesion-promoting effect of the material B leads to the polymer matrix of the new article (600) being present as a homogeneous polymer blend.

6. Method according to claim 5, characterized in that the new article (600) is designed as an injection-molded corner connector or as an extruded thermal separation profile for door or window profiles.

7. The method according to claim 5 or 6, characterized in that the weight ratio of the first raw material (T) to the second raw material (200') is in the range of 10:1 to 20:

1.

8. Method according to one of claims 1 to 7, characterized in that in the first raw material (T) the weight ratio of material A to material B is in the range from 1:2 to 2:

1.

9. Method according to one of claims 1 to 8, characterized in that the second raw material (200') consists of recycled material and / or new material and is preferably free of reinforcing fibers.

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

11. Method according to one of claims 1 to 10, characterized in that the material B is formed as a blend of the materials A and a polymeric material D.

12. Process according to claim 11, characterized in that the weight ratio of materials A and D in the blend is 1:2 to 2:

1.

13. Process according to claim 11 or 12, characterized in that the material D is an acrylonitrile-styrene-acrylate (ASA).

14. Method according to one of claims 1 to 13, characterized in that the material C is a PVC.

15. Method according to one of claims 1 to 14, characterized in that the core profile (10) has an endless fiber reinforcement (5) and is manufactured by reactive pultrusion (3).

16. 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 15, 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 coating has a polymer matrix (15) made of a PA-ASA blend.

17. An article (600) produced by a recycling process according to any one of claims 1 to 15.

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