Crosslinked Polyaryletherketone

Abstract

The present invention relates to molded articles comprising a polymer matrix containing crosslinked polyaryletherketones and to methods for producing such molded articles. The invention also relates to sealing articles for electrical or chemical applications, thrust washers, backup rings, valves, connectors, insulators, snap hooks, bearings, bushings, films, powders, coatings, fibers, seal rings and O-rings, pipes and lines, cables, jackets and sheaths, and casings, which comprise or consist of such molded articles.

Description

[Technical field]

[0001] The present invention relates to a molded article comprising a polymer matrix containing crosslinked polyaryletherketones and a method for producing such a molded article.Furthermore, the present invention relates to sealing articles for electrical or chemical applications, thrust washers, backup rings, valves, connectors, insulators, snap hooks, bearings, bushings, films, powders, coatings, fibers, seal rings and O-rings, pipes and lines, cables, jackets and sheaths and casings comprising or consisting of such a molded article.

[0002] prior art Thermoplastically processable synthetic resins (thermoplastics) are widespread due to their production productivity, reversible moldability and, in many cases, their high-quality technical properties, and are now standard products in industrial production. Thermoplastics consist of substantially linear polymer chains, i.e. they are not crosslinked and are usually only slightly or not branched. However, thermoplastics have limitations with regard to their heat resistance, which are dependent on their intrinsic properties, and therefore are not optimally suited for all areas of application of polymeric materials. It is therefore desirable to increase the heat resistance of thermoplastic synthetic resins without sacrificing advantages such as good mechanical properties or high chemical resistance. In this case, multiply crosslinked polymers (thermosetting plastics, thermosetting resins), in which the macromolecules are linked to each other by covalent bonds, are advantageous. At low temperatures, such polymers are in a hard-elastic state, also called the glassy state. Heating thermosetting plastics beyond this region usually leads directly to the region of thermal decomposition.

[0003] Polyaryletherketones (PAEKs), such as polyetheretherketones (PEEKs), are semicrystalline thermoplastics with high heat and medium resistance and are among the so-called high-performance polymers. They have an alternating structure in which aryl groups are followed in each case by keto groups (carbonyl groups) or ether groups, the ratio of ketone groups to ether groups being variable and the substitution pattern on the aryl rings can be different. Both essentially determine the properties of the PAEKs. PAEKs are characterized in particular by good strength properties even at relatively high temperatures, high impact strength values ​​at low temperatures, high mechanical fatigue strength, a low tendency to creep deformation as well as good sliding and wear behavior. The continuous use temperature is up to about 260 °C, the short-term maximum application limit is close to the melting point (about 373 °C for PEK and about 340 °C for PEEK). They are also used, among other things, for high-performance molded parts, in particular for seals and backup rings in the oil and gas transport sector. In this case, PAEK is characterized by its toughness and chemical resistance, which means that it cannot yet be replaced by other classes of materials. However, PAEK, and especially PEEK, also have limitations in terms of heat resistance given the aforementioned inherent properties typical of thermoplastics. In order to further increase the heat resistance and mechanical stability of PAEK, it has been proposed to crosslink the polymer chains. In the prior art, for crosslinking, the prior art method of crosslinking PAEK with diamines is used. In this case, imine bonds (Schiff bases) are formed, which can give the crosslinked polymer a higher stability. The disadvantage here is that such crosslinked polymers are not flowable. It is therefore not easily possible to process them thermoplastically from the polymer melt. A further disadvantage is that not all diamines which are in principle suitable as crosslinking agents can be used in practice. In particular, amines which are volatile even at low temperatures not only endanger the user, but also lead to significant environmental pollution.

[0004] The chemical crosslinking of polyetheretherketone (PEEK) with diamines has been known since the 1980s. In this method, polyetheretherketone is first modified by binding paraphenylenediamine in diphenylsulfone as solvent. The solvent must then be separated by drying and washing. The problem is that in the described method, and even during covalent bonding, crosslinks are already formed. On the one hand, the heat resistance is indeed increased, but on the other hand, the glass transition temperature is also increased and thermoplastic processability is lost. The resulting polymer mass is therefore not crosslinked thermoplastically from the molten state, but by hot pressing.

[0005] It is further known that PEEK can first be modified by a similar reaction of PEEK with phenylenediamine in diphenylsulfone as solvent, and then crosslinked by hot pressing after separating and washing the solvent. Thermoplastic processing is also not mentioned. Investigations have shown that the product has a higher stability than non-crosslinked PEEK, but there is still room for improvement. In particular, this method leads to an almost complete loss of crystallinity in the solution state, so that the modulus of elasticity above the glassy state is relatively low compared to thermoplastic PEEK.

[0006] WO 2010 / 011725 describes a number of amine-based crosslinkers for crosslinking PAEK, however, this document contains only one synthesis example describing the crosslinking of PAEK with phenylenediamines according to the above cited publication, where the reaction is first carried out in diphenylsulfone as solvent.

[0007] A method for crosslinking PAEK with a non-amine based crosslinker is proposed in US Pat. No. 6,887,408.

[0008] In order to crosslink PAEK, the prior art has also proposed functionalizing the polymer itself with crosslinkable amino groups. Such a method is described, for example, in US 2017 / 0107323. The disadvantage here is that the functionalization of PAEK with amino groups is relatively expensive. Furthermore, the crosslinking of functionalized PAEK cannot be controlled as easily and variably as with low molecular weight crosslinkers.

[0009] WO 2020 / 056052 describes a crosslinkable polymer composition comprising at least one aromatic polymer and at least one crosslinking compound capable of crosslinking the at least one aromatic polymer. A fluorene derivative is used as the crosslinking compound.

[0010] The process for crosslinking PAEK with diamines as low molecular weight crosslinkers described in the prior art is carried out in the presence of a high proportion of solvent and the production of moulded articles is carried out by hot pressing (compression moulding). The product has better temperature stability than comparable non-crosslinked PAEK. However, PAEK crosslinked in this way has the disadvantage of having a relatively low rigidity, due to the loss of crystallinity of the PAEK when the polymer is dissolved in the solvent. If further processed, the crystallinity can only be restored to a small extent, if at all, due to the inherent steric hindrance of the chains by the crosslinking sites. Furthermore, the process has the disadvantage of being very cumbersome overall, since it also requires a large number of work steps for the removal of the solvent. A further disadvantage is that the moulded articles are produced in hot pressing, which limits the applicability compared to thermoplastic processing. Hot pressing and comparable processes are carried out with non-flowable materials that cannot be converted into a thermoplastic melt. As a result, the mouldability is limited and thin-walled or complex moulded articles cannot be produced. For these reasons, such processes can also only be automated to a very limited extent. Therefore, efficient and cost-effective industrial production cannot be achieved based on known solvent-based methods.

[0011] WO 2010 / 011725 generally describes a method for producing shaped articles by extrusion from crosslinked PAEK. However, this is only a theoretical approach, since the production of the products is only carried out on a laboratory scale by hot pressing. There is no evidence that PAEK crosslinked with low molecular weight crosslinkers can be extruded, much less that products with advantageous properties can be obtained in this way. Furthermore, the skilled person has no reasonable expectation of success that PAEK and amine group-containing crosslinkers can be plasticized in an extruder and subsequently subjected to a shaping step. On the one hand, the problem is that crosslinking already starts at the required high melting temperature, at which the components have to be mixed and processed. On the other hand, it was not expected that PAEK would be mixable and processable with such amine-based crosslinkers in the absence of solvents. In practice, when low molecular weight components are incorporated into the polymer, segregation processes are often observed. However, to obtain a stable product, a homogeneous distribution of the crosslinker in the polymer is absolutely necessary.

[0012] WO 2020 / 030599 describes a method for producing crosslinked molded articles containing PAEK. In this publication, the crosslinker is a di(aminophenyl) compound in which two aminophenyl rings are linked to each other via an aliphatic group with a carbon ring residue. In particular, 1-(4-aminophenyl)-1,3,3-trimethylindan-5-amine DAPI (CAS number 54628-89-6) or an isomer mixture (CAS number 68170-20-7) is used as the crosslinker component. On the one hand, the high production costs of the crosslinker are a disadvantage. On the other hand, the physicochemical properties of PAEK crosslinked with DAPI need improvement.

[0013] US Patent Application Publication No. 2020 / 0172669 and US Patent Application Publication No. 2020 / 0172667 describe crosslinkable polymer compositions comprising at least one aromatic polymer and at least one crosslinking compound capable of crosslinking the aromatic polymer. Derivatives of fluorene, diphenylmethane and dihydroanthracene are used as the crosslinking compound.

[0014] The problem underlying the present invention is to provide a method and product which overcomes the above mentioned drawbacks.

[0015] In particular, a PAEK-based material should be provided that has high stability and good processability. In particular, the material should have high heat resistance and high stiffness (elastic modulus) at high temperatures. Furthermore, it should have good chemical resistance and low flammability. Furthermore, the material should show a low creep tendency and rubber-elastic behavior in the high temperature range.

[0016] In particular, the object of the present invention is to provide a material that has high stability and is easily processable. This material should be able to be produced efficiently and cost-effectively in a simple manner. In particular, it is advantageous if the material can be thermoplastically processed and can be appropriately crosslinked only after shaping. In particular, inefficient methods such as hot pressing should be avoided.

[0017] The method should also be as environmentally friendly as possible and be possible to carry out without exposing the user to danger.

[0018] Surprisingly, the problem underlying the present invention is solved by a method, moldings and sealing articles, in which polyaryletherketones are subjected to crosslinking with a special diamine source to form imine groups. In this method, a plasticized mixture of polyaryletherketones and diamine sources can first be subjected to a shaping process to produce a molding. The molding can then be subjected to crosslinking. These two steps can also be partially combined into one step in an injection molding machine.

[0019] Summary of the Invention A first subject of the invention is a moulded article with a matrix resulting from the reaction of a polyaryletherketone (PAEK) with at least one crosslinking agent capable of thermally crosslinking with the keto groups of the PAEK to form at least two imine groups per crosslinking agent molecule, the crosslinking agent being a) an oligomer / polymer having at least two amide groups, or having at least one amide group and at least one primary amino group, or having at least two imide groups, or having at least one imide group and at least one primary amino group; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof The molded article is selected from the following:

[0020] A preferred embodiment is a molded article with a matrix resulting from the reaction of a polyaryletherketone with at least one crosslinker selected from polyamides, polyimides, aminated dimeric fatty acids, oligomers / polymers containing aminated dimeric fatty acids as copolymerized units and mixtures thereof.

[0021] Needless to say, PEAK can also be present in the form of a polymer blend / mixture. Suitable mixing partners are selected from among high performance thermoplastics, in particular polyphenylene sulfide (PPS), polyamide-imide (PAI), polyphthalamide (PPA), polysulfone (PSU), thermoplastic polyimide (TPI), polyethersulfone (PES or PESU), polyphenylene ether (PPE), polyphenylene sulfone (PPSU) and liquid crystal polymer (LCP).

[0022] A further subject of the invention is a molding in the form of a coating.

[0023] A further object of the present invention is a method for producing a moulded article, comprising the steps of: i) preparing a mixture containing at least one polyaryletherketone and at least one crosslinking agent, the at least one crosslinking agent being a) an oligomer / polymer having at least two amide groups, or having at least one amide group and at least one primary amino group, or having at least two imide groups, or having at least one imide group and at least one primary amino group; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof and ii) producing a molded article from the mixture obtained in step i); iii) heat treating the molded article at a temperature at which the polyaryletherketone is crosslinked; The method includes:

[0024] The subject of the invention is also the mouldings obtained by this process.

[0025] The subject of the present invention is also a polymer mixture as defined above and below, containing at least one polyaryletherketone (PAEK) and at least one crosslinking agent. With regard to suitable and preferred PAEKs and crosslinking agents contained in the polymer mixture, in the context of the moldings according to the invention and their production, reference is made in full to the following description.

[0026] A subject of the invention is also a shaped article precursor as defined above and below, obtainable by a process comprising steps i) and ii).

[0027] The subject of the invention is also the use of the shaped articles as defined above and below, or obtained by the process as defined above and below, in the automotive, maritime, aerospace, rail vehicles, oil and gas industry, food and packaging industry and medical technology sectors.

[0028] Further objects of the invention are sealing articles for electrical or chemical applications, thrust washers, backup rings, valves, connectors, insulators, snap hooks, bearings, bushes, films, powders, coatings, fibres, sealing rings and O-rings, pipes and lines, cables, jackets and sheaths and casings which consist of or comprise the mouldings according to the invention or the mouldings obtained according to the process according to the invention.

[0029] Description of the Invention The polymer composition according to the invention, the moulded article according to the invention and the process according to the invention have the following advantages: In the process according to the invention for producing moldings based on crosslinked PAEK, substances that are potentially harmful to the environment and to health, such as, for example, volatile aromatic amines, are avoided. The crosslinked polyaryletherketones used according to the invention and the moulded articles according to the invention are characterised by a higher heat resistance and a higher maximum use temperature than non-crosslinked PAEKs, they have a high glass transition range, in particular a higher glass transition range compared to DAPI crosslinked polyaryletherketones. The crosslinked polyaryletherketones used according to the invention or the moulded articles according to the invention show a high level of the rubber plateau in dynamic mechanical analysis (DMA), in particular an approximately 10-fold higher level of the rubber plateau above the melting region compared to DAPI crosslinked polyaryletherketones. The process according to the invention is characterized by low costs, especially lower costs compared to PAEK crosslinking with DAPI and other aromatic diamines. The diamine sources used according to the invention are usually commercially available raw materials with low production costs. - Polyamides can be used as a source of low molecular weight polyamides and diamines. Depending on the reaction conditions, it is possible to control which crosslinker components are formed from the polyamide. Thus, by using polyamides as a diamine source, it is also possible to crosslink PAEKs with low-boiling aliphatic diamines, which otherwise cannot be reacted with PEAKs for process / safety / environmental reasons or can only be reacted with great effort. The process according to the invention is technically simple to carry out, since only the two components (granulates) need to be conveyed and mixed. The polymer compositions according to the invention or the mouldings according to the invention have very good tribological properties: they are suitable as materials for use under abrasive wear conditions, for example as seal and plain bearing materials in conveying devices for corrosive and abrasive media. The polymer compositions according to the invention or the moulded articles according to the invention exhibit lower swelling, in particular in comparison with DAPI-crosslinked polyaryletherketones. - Based on the long-established ingredients used, Reach registration of the polymer is not required. The process according to the invention is sustainable: the non-crosslinked residues can be easily and easily recycled and do not have to be sent to waste.

[0030] Polyaryletherketone In polyaryletherketones (PAEKs), aryl groups are present between the functional groups in each case bonded in the (1,4 and / or 1,3) position. Polyaryletherketones have a semicrystalline, rigid structure that gives the materials relatively high glass transition and melting temperatures.

[0031] As polymer component, in principle any polyaryletherketone can be used. Polyaryletherketones are characterized by linear polymer chains from aryl, ether and keto groups. Compounds of this substance class differ in terms of different arrangements of these groups and their ratio in the molecule. PAEKs can be, for example, polyetheretherketones (PEEK), polyetherketones (PEK), poly(etherketoneketones) (PEKK), poly(etheretheretherketones) (PEEEK), poly(etherketoneetherketoneketones) (PEKEKK) or poly(etheretherketoneketones) (PEEKK). Compounds of this substance class have keto groups that can react with primary amines to form imine groups (Schiff bases). Polyaryletherketones can therefore be covalently bonded (crosslinked) with diamines or diamine sources via imine bonds. It is also possible to use mixtures of different polyaryletherketones. It is preferable to use a single PAEK, since this allows a high degree of crystallinity and the associated temperature stability to be obtained.

[0032] In another embodiment, PEAK is used in the form of a polymer blend / mixture. Suitable mixing partners are selected from among high performance thermoplastics, in particular polyphenylene sulfide (PPS), polyamideimide (PAI), polyphthalamide (PPA), polysulfone (PSU), thermoplastic polyimide (TPI), polyethersulfone (PES or PESU), polyphenylene ether (PPE), polyphenylene sulfone (PPSU) and liquid crystal polymer (LCP). In a preferred embodiment, the polyaryletherketone (PAEK) is polyetheretherketone (PEEK, CAS number 29658-26-2). Particularly preferably, the polyaryletherketone (PAEK) is polyetheretherketone (PEEK) with a melting range of 335°C to 345°C. It has been found that PEEK crosslinked according to the invention has particularly advantageous properties with regard to temperature and mechanical stability.

[0033] Preferably, the polyaryletherketone (PAEK) has a melting point of 5 cm at 380° C. 3 / 10 minutes~250cm 3 / 10 minutes, especially 50cm 3 / 10 minutes~200cm 3 The melt viscosity ranges from 1000 to 10000 / 10 min. The measurement is carried out according to DIN ISO 1133, where the material is melted at 380 ° C and loaded with a 5 kg stamp, after which the flowability is determined. Usually, commercially available PAEK, especially PEEK variants are suitable. The melt viscosity generally correlates with the molecular weight of the polymer chain. According to the invention, such melt viscosity has been found to be advantageous, since both good thermoplastic processability and miscibility are achieved, and homogeneous products with high stability, especially high rigidity, can also be obtained.

[0034] Suitable PAEKs are commercially available, for example Vestakeep 2000 (melt volume rate, ISO1133 (380°C / 5kg) 70ml / 10min), KetaSpire KT820 (melt flow rate, ASTM D1238 (400°C / 2.16kg) 3g / 10min).

[0035] Preferably, the crosslinking agent is used in an amount of 0.05% by weight to 30% by weight, preferably 0.1% by weight to 30% by weight. It is particularly preferred to use PEEK as PAEK, especially one having the melt viscosity as described above. In this case, the crosslinking agent is preferably used in an amount of 0.05% by weight to 30% by weight, preferably 0.1% by weight to 20% by weight, based on the total weight of PEEK and crosslinking agent. With such a ratio and the properties of the starting materials, it is possible to achieve particularly good processability and temperature stability of the product.

[0036] In a first preferred embodiment, the oligomer / polymer is used in an amount of 0.5% to 30% by weight, in particular 1 to 10% by weight, based on the total weight of polyaryletherketone and crosslinker.

[0037] In a second preferred embodiment, a saturated alicyclic compound different from the oligomer / polymer is used in an amount of 0.05 to 10% by weight, in particular 0.1 to 5% by weight, based on the total weight of the polyaryletherketone and the crosslinker.

[0038] In particular, the stiffness is particularly high, which is characterized by a high tensile modulus at high temperatures. Moreover, such PAEKs, especially PEEKs, can be processed at temperatures that still allow thermoplastic mixing with the crosslinking agent, without the crosslinking reaction proceeding too rapidly during the preparation of the mixture (=step i)). As a result, plasticized masses are obtained that can be very well used in molding processes (=step ii)) for the production of moldings. The moldings thus obtained can be subsequently subjected to a heat treatment (step iii)), in which the final material properties are achieved by crosslinking of the PAEK.

[0039] In a further embodiment, the PAEK is present in a mixture with at least one further polymer. The further polymer is in particular a thermoplastic polymer. Preferred further polymers are selected from polyphenylene sulfide (PPS), polyamideimide (PAI), polyphthalamide (PPA), thermoplastic polyimide (TPI), polysulfone (PSU), polyethersulfone (PES or PESU), polyphenylenesulfone (PPSU), polyphenylene ether (PPE) and liquid crystal polyester (LCP) and mixtures thereof. The preferred weight ratio between the PAEK and the further polymer, in particular between the PAEK and the further thermoplastic polymer, is 1:1 to 100:1, advantageously 5:1 to 100:1, particularly preferably 10:1 to 100:1.

[0040] Crosslinking Agent Preferably, the crosslinking agent used for the crosslinking of the PAEK is at least 20% by weight, preferably at least 50% by weight, particularly preferably at least 80% by weight, in particular at least 90% by weight, in particular at least 99% by weight, based on the total weight of the crosslinking agent, a) an oligomer / polymer having at least two amide groups, or having at least one amide group and at least one primary amino group, or having at least two imide groups, or having at least one imide group and at least one primary amino group; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof is selected from among:

[0041] This applies analogously to the crosslinker prepared in step i) of the method according to the invention.

[0042] The amount of crosslinker is set in the light of the desired degree of crosslinking. Preferably, the proportion of crosslinker is 0.05% to 30% by weight, in particular 0.1% to 30% by weight, based on the total weight of the crosslinker and the PAEK. In a preferred embodiment, the proportion of crosslinker is 0.1 to 10% by weight. It has been found that the stability of the product with such a crosslinker proportion can be particularly advantageous. In particular, a significant improvement in the elongation at break can be achieved when the amount of crosslinker is set in this range.

[0043] In a first preferred embodiment, the crosslinker is selected from among oligomers / polymers a) having at least two amide groups, or having at least one amide group and at least one primary amino group, or having at least two imide groups, or having at least one imide group and at least one primary amino group.

[0044] In the sense of the present invention, the term "oligomer / polymer" refers to a polymer molecule in which at least two monomer building blocks (repeating units) are covalently linked. The monomers also have one or more polymerizable groups that can react with identical or complementary groups of further monomers. For example, oligoamides / polyamides can result from the reaction of at least one dicarboxylic acid (AA type monomer) with at least one diamine (BB type monomer) or from the reaction of at least one lactam (AB type monomer).

[0045] In one embodiment, at least one crosslinker is an oligomer / polymer having at least two amide groups.

[0046] In the following, the term polyamide is used synonymously with an oligomer / polymer having at least two amide groups.

[0047] If polyamides are referred to below as crosslinkers, this term also includes low molecular weight products formed during the reaction in the process according to the invention (e.g. from hydrolytic cleavage of amide groups to form amine groups capable of reacting with keto groups of the PAEK), in so far as these are capable of crosslinking the PAEK. In this respect, both the polyamides used to prepare the mixtures from polyaryletherketones and crosslinkers, as well as any amine group-containing oligomers and diamine monomers therefrom, can be used as crosslinkers.

[0048] In the following, homo- and copolyamides are grouped together under the term polyamide. In the context of the present invention, the customary abbreviations PA followed by numbers and letters are used to designate polyamides. Some of these abbreviations are defined in DIN EN ISO 1043-1. 2 N-(CH 2 ) zPolyamides that can be derived from aminocarboxylic acids of the -COOH type or the corresponding lactams are designated PAZ, where Z represents the number of carbon atoms in the monomer. For example, PA6 represents the polymer of ε-caprolactam or ε-aminocaproic acid. 2 N-(CH 2 ) x -NH 2 Type and HOOC-(CH 2 ) y Polyamides that can be derived from diamines and dicarboxylic acids of the -COOH type are designated PAxy, where x refers to the number of carbon atoms in the diamine and y refers to the number of carbon atoms in the dicarboxylic acid. To designate a copolyamide, the components are listed in the order of their proportions, separated by slashes. For example, PA66 / 610 is a copolyamide of hexamethylenediamine, adipic acid and sebacic acid. The following letter abbreviations are used for the monomers with aromatic or cycloaliphatic groups used according to the invention: T = terephthalic acid, I = isophthalic acid, MXDA = m-xylylenediamine, IPDA = isophoronediamine, PACM = 4,4'-methylenebis(cyclohexylamine), MACM = 2,2'-dimethyl-4,4'-methylenebis(cyclohexylamine).

[0049] Polyamides can be described by the monomers used in their production. Polyamide-forming monomers are monomers suitable for the formation of polyamides.

[0050] In a preferred embodiment, the crosslinker comprises an oligomer / polymer having at least two amide groups, the oligomer / polymer comprising: A) unsubstituted or substituted aromatic dicarboxylic acids and derivatives of unsubstituted or substituted aromatic dicarboxylic acids, B) unsubstituted or substituted aromatic diamines, C) aliphatic or cycloaliphatic dicarboxylic acids, D) aliphatic or cycloaliphatic diamines, E) monocarboxylic acids, F) monoamines, G) at least trivalent amines, H) lactam, I) ω-amino acids and K) Compounds other than A) to I) that can be co-condensed with them, and mixtures thereof The polyamide-forming monomers are selected from the following copolymers: However, at least one of components A) or C) and at least one of components B) or D) must be present.

[0051] In a preferred embodiment of the present invention, semi-aromatic polyamides are used as crosslinking agents.To this end, the condition applies that at least one of components A) or B) and at least one of components C) or D) must be present.In a specific embodiment, the condition applies that at least one component A) and at least one component D) must be present.

[0052] The aromatic dicarboxylic acid A) is preferably selected from among unsubstituted or substituted phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid or diphenyldicarboxylic acid, respectively, and also derivatives and mixtures of the aforementioned aromatic dicarboxylic acids. The substituted aromatic dicarboxylic acid A) advantageously comprises at least one C 1 ~C 4 Particularly preferably, the substituted aromatic dicarboxylic acids A) have one or two C 1 ~C 4The aromatic dicarboxylic acids A) have alkyl residues. These are advantageously selected from among methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, particularly preferably methyl, ethyl and n-butyl, very particularly preferably methyl and ethyl, especially methyl. The substituted aromatic dicarboxylic acids A) may have further functional groups that do not interfere with the amidation, such as 5-sulfoisophthalic acid, its salts and derivatives. Among these, the sodium salt of 5-sulfoisophthalic acid dimethyl ester is preferred. The aromatic dicarboxylic acids A) are preferably selected from among unsubstituted terephthalic acid, unsubstituted isophthalic acid, unsubstituted naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid and 5-sulfoisophthalic acid. Particularly preferably, terephthalic acid, isophthalic acid or a mixture of terephthalic acid and isophthalic acid is used as aromatic dicarboxylic acid A).

[0053] The aromatic diamine B) is preferably selected from among bis-(4-aminophenyl)methane, 3-methylbenzidine, 2,2-bis-(4-aminophenyl)propane, 1,1-bis-(4-aminophenyl)cyclohexane, 1,2-diaminobenzene, 1,4-diaminobenzene, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 1,3-diaminotoluene, m-xylylenediamine, N,N'-dimethyl-4,4'-biphenyldiamine, bis-(4-methylaminophenyl)methane, 2,2-bis-(4-methylaminophenyl)propane or mixtures thereof. Particularly preferably, m-xylylenediamine is used as aromatic diamine.

[0054] The aliphatic or cycloaliphatic dicarboxylic acids C) are advantageously selected from among oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecane-1,11-dicarboxylic acid, dodecane-1,12-dicarboxylic acid, maleic acid, fumaric acid or itaconic acid, cis- and trans-cyclohexane-1,2-dicarboxylic acid, cis- and trans-cyclohexane-1,3-dicarboxylic acid, cis- and trans-cyclohexane-1,4-dicarboxylic acid, cis- and trans-cyclopentane-1,2-dicarboxylic acid, cis- and trans-cyclopentane-1,3-dicarboxylic acid and mixtures thereof.

[0055] The aliphatic or cycloaliphatic diamine D) is preferably ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 2-methyl-1,8-octamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2-methylpentamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, 2,4-dimethyloctamethylenediamine, 5- The amine is selected from among methylnonanediamine, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, 1,3-bis(aminomethyl)cyclohexane and 1,4-bisaminomethylcyclohexane, 5-amino-2,2,4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine (isophoronediamine), 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, [3-(aminomethyl)-2-bicyclo[2.2.1]heptanyl]methanamine, aminated dimeric fatty acids and mixtures thereof.

[0056] Particularly preferably, the diamine D) is selected from among hexamethylenediamine, 2-methylpentamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, bis-(4-aminocyclohexyl)methane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane and mixtures thereof. In a preferred embodiment of the invention, the aqueous solution contains at least one diamine D) selected from among hexamethylenediamine, bis-(4-aminocyclohexyl)methane (PACM), 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane (MACM), isophoronediamine (IPDA) and mixtures thereof.

[0057] Monocarboxylic acids E) are used for the final capping of the polyamide oligomers used according to the invention. In principle, all monocarboxylic acids are suitable that can react with at least a portion of the available amino groups under the reaction conditions of the polyamide condensation. Suitable monocarboxylic acids E) are aliphatic monocarboxylic acids, cycloaliphatic monocarboxylic acids and aromatic monocarboxylic acids. These include acetic acid, propionic acid, n-butyric acid, isobutyric acid or tert-butyric acid, valeric acid, trimethylacetic acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, cyclohexanecarboxylic acid, benzoic acid, methylbenzoic acid, 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, phenylacetic acid, oleic acid, ricinoleic acid, linoleic acid, linolenic acid, erucic acid, fatty acids from soybean, linseed, castor bean and sunflower, acrylic acid, methacrylic acid, tertiary saturated monocarboxylic acids (for example Versatic® acid from Royal Dutch Shell plc) and mixtures thereof.

[0058] When an unsaturated carboxylic acid or its derivative is used as the monocarboxylic acid E), it may be useful to add a commercially available polymerization inhibitor to the aqueous solution. Particularly preferably, the monocarboxylic acid E) is selected from among acetic acid, propionic acid, benzoic acid and mixtures thereof. In a particularly highly preferred embodiment, the aqueous solution contains only acetic acid as the monocarboxylic acid E). In a further particularly highly preferred embodiment, the aqueous solution contains only propionic acid as the monocarboxylic acid E). In a further particularly highly preferred embodiment, the aqueous solution contains only benzoic acid as the monocarboxylic acid E).

[0059] Monoamines F) are used for the final capping of the polyamide oligomers used according to the invention. In principle, all monoamines are suitable that are capable of reacting with at least a portion of the available carboxylic acid groups under the reaction conditions of the polyamide condensation. Suitable monoamines F) are aliphatic, cycloaliphatic and aromatic monoamines. These include methylamine, ethylamine, propylamine, butylamine, hexylamine, heptylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, cyclohexylamine, dicyclohexylamine, aniline, toluidine, diphenylamine, naphthylamine and mixtures thereof.

[0060] Suitable at least trivalent amines G) are N'-(6-aminohexyl)hexane-1,6-diamine, N'-(12-aminododecyl)dodecane-1,12-diamine, N'-(6-aminohexyl)dodecane-1,12-diamine, N'-[3-(aminomethyl)-3,5,5-trimethyl-cyclohexyl]hexane-1,6-diamine, N'-[3-(aminomethyl)-3,5,5-trimethyl-cyclohexyl]dodecane-1,12-diamine, N'-[(5-amino-1,3,3-trimethyl-cyclohexyl)methyl]hexane-1,6-diamine, N'- [(5-amino-1,3,3-trimethyl-cyclohexyl)methyl]dodecane-1,12-diamine, 3-[[[3-(aminomethyl)-3,5,5-trimethyl-cyclohexyl]amino]methyl]-3,5,5-trimethyl-cyclohexanamine, 3-[[(5-amino-1,3,3-trimethyl-cyclohexyl)methylamino]methyl]-3,5,5-trimethyl-cyclohexanamine, 3-(aminomethyl)-N-[3-(aminomethyl)-3,5,5-trimethyl-cyclohexyl]-3,5,5-trimethyl-cyclohexanamine. Preferably, at least trivalent amines G) are not used.

[0061] Suitable lactams H) are ε-caprolactam, 2-piperidone (δ-valerolactam), 2-pyrrolidone (γ-butyrolactam), capryllactam, enantholactam, lauryllactam and mixtures thereof.

[0062] Suitable ω-amino acids I) are 6-aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and mixtures thereof.

[0063] Suitable compounds K) which are different from A) to I) and can be co-condensed with them are at least trivalent carboxylic acids, diaminocarboxylic acids, etc. Suitable compounds K) are furthermore 4-[(Z)-N-(6-aminohexyl)-C-hydroxy-carbonimidoyl]benzoic acid, 3-[(Z)-N-(6-aminohexyl)-C-hydroxy-carbonimidoyl]benzoic acid, (6Z)-6-(6-aminohexylimino)-6-hydroxy-hexanecarboxylic acid, 4-[(Z)-N-[(5-amino-1,3,3-trimethyl-cyclohexyl)methyl]-C-hydroxy-carbonimidoyl]benzoic acid, 3-[(Z)-N-[(5-amino-1,3,3-trimethyl-cyclohexyl)methyl]-C-hydroxy-carbonimidoyl]benzoic acid, 4-[(Z)-N-[3-(aminomethyl)-3,5,5-trimethyl-cyclohexyl]-C-hydroxy-carbonimidoyl]benzoic acid, 3-[(Z)-N-[3-(aminomethyl)-3,5,5-trimethyl-cyclohexyl]-C-hydroxy-carbonimidoyl]benzoic acid and mixtures thereof.

[0064] In a further preferred embodiment of the present invention, semi-aromatic or aliphatic polyamides are used as crosslinkers, in which case the polyamides are preferably selected from the group consisting of PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T, PA6.I, PA8.I, PA9.I, PA10.I, PA12.I, PA6.T / 6, PA6.T / 10, PA6.T / 12, PA6.T / 6.I, PA6.T / 8.T, PA6.T / 9.T, PA6.T / 10.T, PA6.T / 12.T, PA12.T / 6.T, PA6.T / 6.I / 6, PA6.T / 6.1 / 12, PA6.T / 6.I / 6.10, PA6.T / 6.I / 6.12, PA6.T / 6. .6, PA6.T / 6.10, PA6.T / 6.12, PA10.T / 6, PA10.T / 11, PA10.T / 12, PA8.T / 6.T, PA8.T / 66, PA8.T / 8.I, PA8.T / 8.6, PA8.T / 6.I, PA10.T / 6.T, PA10.T / 6 .6. MXDA.6, PA6.T / IPDA.T, PA6.T / MACM.T, PA6.T / PACM.T, PA6.T / MXDA.T, PA6.T / 6.I / 8.T / 8.I, PA6.T / 6.1 / 10.T / 10.1, PA6.T / 6.I / IPDA.T / IPDA.I, PA6.T / 6.I / MXDA.T / MXDA.I, PA6.T / 6.I / MACM.T / MACM.I, PA6. The preferred embodiment of the invention is selected from among PA6.T / 6.I / PACM.T / PACM.I, PA6.T / 10.T / IPDA.T, PA6.T / 12.T / IPDA.T, PA6.T / 10.T / PACM.T, PA6.T / 12.T / PACM.T, PA10.T / IPDA.T, PA12.T / IPDA.T, PA4.6, PA6.6, PA6.12, PA6.10 and copolymers and mixtures thereof.In this case, the polyamides are particularly preferably PA4.T, PA5.T, PA6.T, PA9.T, PA10.T, PA12.T, PA6.I, PA9.I, PA10.I, PA12.I, PA6.T / 6.I, PA6.T / 6, PA6.T / 8.T, PA6.T / 10.T, PA10.T / 6.T, PA6.T / 12.T, PA12.T / 6.T, PA IPDA.I, PA IPDA.T, PA6.T / IPDA.T, PA6.T / 6.I / IPDA.T / IPDA.I, PA6.T / 10.T / IPDA.T, PA6.T / 12.T / IPDA.T, PA6.T / 10.T / PACM.T, PA6.T / 12.T / PACM.T, PA10.T / IPDA.T, PA12.T / IPDA.T and copolymers and mixtures thereof.

[0065] Further preferred configurations are oligo / polyamides a) which incorporate and contain at least one amine selected from among saturated cycloaliphatic compounds having at least two primary amino groups. Suitable saturated cycloaliphatic diamines and polyamines are described below as crosslinkers b) and are fully incorporated herein by reference. A specific embodiment is an oligo / polyamide a) which incorporates and contains at least one aminated dimeric fatty acid. A further specific embodiment is an oligo / polyamide a) which incorporates and contains at least one aminated dimeric fatty acid. [ka] The oligo / polyamide a) contains

[0066] In a further preferred configuration, the oligomer / polymer a) has at least two imide groups. These include, for example, polyimides selected from among polyamideimides (PAI) and thermoplastic polyimides (TPI).

[0067] In a second preferred embodiment, the crosslinker is selected from among saturated alicyclic compounds b) different from a) and having at least two primary amino groups. Suitable saturated alicyclic diamines and polyamines have one or more non-aromatic rings, the ring atoms are only carbon atoms, and the ring system has an aliphatic structure. Preferably, the crosslinker b) comprises at least one saturated alicyclic diamine or consists of a saturated alicyclic diamine. Preferred saturated alicyclic diamines are selected from among bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, 1,3-bis(aminomethyl)cyclohexane and 1,4-bisaminomethylcyclohexane, 5-amino-2,2,4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine (isophoronediamine), 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, [3-(aminomethyl)-2-bicyclo[2.2.1]heptanyl]methanamine, aminated dimeric fatty acids and mixtures thereof.

[0068] In a preferred embodiment, the saturated alicyclic compounds b) having at least two primary amino groups are present as liquids. They can therefore be used as internal solvents in step ii) of the process according to the invention, in particular during melt mixing. Preferably, the saturated alicyclic oligomers are aminated fatty acid dimers.

[0069] The term "fatty acid dimer" as used herein refers to the dimerization product of the reaction of two or more mono- or polyunsaturated fatty acids. Such fatty acid dimers are well known in the prior art and typically exist as mixtures.

[0070] Aminated dimer fatty acid (also called aminated dimerized fatty acid or dimer acid) refers to a mixture produced by the oligomerization of unsaturated fatty acids. 12 ~C 22 Fatty acids can be used as starting materials. C used to produce dimeric fatty acids 12 ~C 22Depending on the number and position of the double bonds in the fatty acid, the amine groups of the dimeric fatty acids are linked to each other by hydrocarbon residues, mainly having 24 to 44 carbon atoms. These hydrocarbon residues can be unbranched or branched, and can have double bonds, C 6 Cycloaliphatic hydrocarbon residue or C 6 It may have aromatic hydrocarbon residues, and the cycloaliphatic and / or aromatic residues may be present in condensed form. Advantageously, the residues linking the amine groups of the dimeric fatty acids do not have aromatic hydrocarbon residues, and very particularly preferably do not have unsaturated bonds. Particularly preferred are those of 18 They are dimers of fatty acids, i.e. fatty acid dimers having 36 C atoms. They are obtained, for example, by dimerization of oleic acid, linoleic acid and linolenic acid and mixtures thereof. Dimerization is optionally followed by hydrogenation and then amination.

[0071] In certain embodiments, the saturated alicyclic oligomer is [ka] It is.

[0072] In a further preferred embodiment, the at least one crosslinker is a mixture comprising a) a polymer having at least one amide group and b) a saturated alicyclic compound having at least two primary amino groups.

[0073] It is also possible to use a mixture of two or more cross-linking agents.

[0074] The method according to the invention involves a crosslinking reaction in which the polymer chains of the polyaryletherketone are covalently and intermolecularly bonded to one another.

[0075] Step (i) In step (i), a mixture containing polyaryletherketone and crosslinking agent is prepared. The mixture prepared in step (i) can be produced by a conventional compounding method. In step (i), preferably, at least one polyaryletherketone, at least one crosslinking agent, optionally a filler and a reinforcing agent, and optionally at least one further additive different therefrom are melt-mixed or dry-mixed (compounded).

[0076] In melt mixing or melt mixing, the polymers are heated above their melting temperature and intensively mixed by rolling, kneading or extrusion. In this case, the temperature of step (i) is preferably set so that the mixture is easily processable and has a suitable viscosity for compounding. Furthermore, the temperature of step (i) is preferably set so that no substantial reaction has yet occurred between the polyaryletherketone and the crosslinking agent. It is advantageous here that the amine crosslinking of the polyaryletherketone with the crosslinking agent described according to the invention only starts at higher temperatures. Prior covalent bonding of the crosslinking agent to the polyaryletherketone, as described in the prior art, is not necessary in the method according to the invention.

[0077] In one embodiment, in step i), at least one polyaryletherketone, at least one crosslinking agent, optionally fillers and reinforcing agents, and optionally at least one further additive different therefrom, are fed to an extruder, mixed in a plasticized state and optionally granulated.

[0078] In a further embodiment, in step i), preferably at least one polyaryletherketone, at least one crosslinking agent, optionally at least one filler and reinforcing agent, and optionally at least one further additive different therefrom are dry mixed. The above components can be mixed by any known dry mixing technique. A dry mixture (dry blend) of polyaryletherketone, at least one crosslinking agent, optionally at least one filler and reinforcing agent, and optionally at least one further additive different therefrom is obtained.

[0079] During the preparation of the mixture, intensive mixing is carried out by suitable means such as stirring or kneading equipment to achieve uniform distribution of crosslinking agent in the polymer.This is very important to obtain uniform material properties in terms of stability.Preferably, after preparation, the crosslinkable mixture is further processed in step (ii) without further intermediate steps that change the composition.

[0080] During mixing (compounding), intermediate products, such as granules, can be obtained, which are stable for long periods at temperatures below 80° C., advantageously below 50° C., in particular in the range below ambient temperature, and can, for example, be stored intermediately and / or transported to another location and further processed.

[0081] In a particularly preferred embodiment of the invention, the mixture does not contain a solvent. In particular, no external solvent is added to the mixture. Surprisingly, it has been found according to the invention that the mixture of PAEK and crosslinker can be processed without the use of a solvent and intimate mixing occurs.

[0082] Preferably, the mixture is heated to a temperature at which it exists in liquid or flowable (plastic) form. In order to obtain a homogeneous mixture, it is preferable in this case to select the temperature and residence time such that no significant crosslinking occurs.

[0083] In a preferred embodiment, for the preparation of the mixture in step i), the crosslinking agent is added continuously to the PAEK. The components can be in liquid or solid form. In this way, a particularly homogeneous mixture can be obtained. The addition of the crosslinking agent is preferably carried out, for example, by stirring, kneading, rolling and / or extrusion, leading to thorough mixing. In a preferred embodiment, the crosslinking agent is provided in the form of a concentrate, for example as a masterbatch in the oligomeric / polymeric component. This has the advantage that the crosslinking agent can be better metered in and thus the homogeneity of the mixture can be improved. Overall, by the continuous addition of the crosslinking agent, a particularly homogeneous mixture can be obtained and thus a particularly regular crosslinking is achieved. As a result, it is possible to avoid the occurrence of areas of different crosslinking degrees, which could lead to inhomogeneities and damage the product when subjected to thermal or mechanical loads. In this way, particularly good properties can be achieved with respect to temperature stability and mechanical stability.

[0084] Step (ii) In step (ii), a molded article is produced from the mixture. Step (ii) of producing the molded article includes any means of bringing the mixture into a three-dimensional shape that is retained in the cured crosslinked state. Advantageously, the molded article is produced by a shaping method that is customary for thermoplastics. Preferably, the molded article is produced before and / or during crosslinking. It is usually not important if the mixture used in step ii) already contains small amounts of crosslinked products. Particularly preferably, shaping is carried out before step (iii). Because the mixture is advantageously thermoplastically processable and shapingable before crosslinking, especially by hot pressing, extrusion, injection molding and / or additive manufacturing methods.

[0085] If in step i) the mixing of the components is carried out by dry mixing, in step ii) the dry mix is ​​melted and subjected to a shaping step as described above.

[0086] In one embodiment, steps i) and ii) are performed separately and sequentially. In another embodiment, steps i) and ii) are performed simultaneously.

[0087] In a preferred embodiment, the production of the molded article is carried out in step (ii) by thermoplastic molding. This means that the mixture can be molded from the melt in a non-crosslinked and / or at least not significantly crosslinked state, since otherwise thermoplastic processing would no longer be possible. If too many crosslinking sites are present, the PAEK intermediate is no longer flowable and is no longer easily thermoplastically moldable. The mixture must be exposed to high processing temperatures only briefly before shaping. Thermoplastic processing is therefore preferably carried out so that the residence time of the mixture in the device is as short as possible. Preference is given here to carrying out processing in such a way that the essential part of the crosslinking reaction takes place only after shaping, i.e. in step (iii).

[0088] In a preferred embodiment, the mixture is processed in step (ii) by extrusion, hot pressing, injection molding and / or additive manufacturing, thereby forming a master shape. If necessary, the mixture from which the master shape is formed may be reformed before step (iii). These methods are particularly suitable for simple and efficient processing of thermoplastic polymer compositions.

[0089] In this case, extrusion can be carried out according to known methods. During extrusion, a solid to viscous, hardenable mass is continuously forced under pressure through a shape-imparting orifice (also called a nozzle, die or mouthpiece). This results in a body of theoretically any length and with the cross section of the orifice, called the extrudate. Hot pressing is a method in which the molding material is introduced into a preheated cavity. The cavity is then closed using a pressure piston. This pressure causes the molding material to assume the shape defined by the tool.

[0090] Injection molding (sometimes called injection molding or injection molding process) is a shaping method used in processing synthetic resins. In this case, synthetic resin is plasticized in an injection molding machine and injected under pressure into a mold, which is an injection molding tool. Inside the tool, the material cools back to a solid state and is removed as a molded part after the tool is opened. The cavity of the tool determines the shape and surface structure of the product.

[0091] Further methods for producing molded articles are, for example, additive manufacturing methods such as Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS) and all other methods described in guideline VDI 3405.

[0092] Processing by extrusion followed by injection moulding is particularly preferred. The mixture of PAEK and crosslinker is melted in these processes if it is not already present in liquid form. The mixture is advantageously introduced in step (ii) into an extruder, an injection moulding machine or a hot press, melted at high temperatures, for example up to 450° C., and brought to the desired shape.

[0093] Step (iii) Step (iii) consists in heat treating the moulding at a temperature at which the PAEK is crosslinked, thereby obtaining a crosslinked moulding. This allows the PAEK to be intermolecularly crosslinked with a crosslinking agent. In this case, the polyamide used as crosslinking agent is hydrolysed and cleaved into oligomer / diamine components. During crosslinking, two imine bonds are formed between the two keto groups of the PAEK chain and the two amino groups of the free diamine of the crosslinking agent. The resulting bridges in the form of imines are also called Schiff bases, since the imine nitrogens do not carry hydrogen atoms and are bonded to organic molecules. The crosslinking is carried out as completely as possible, so that as many amino groups as possible of the crosslinking agent used react with the carbonyl groups of the PAEK. The advantage of complete crosslinking is an increase in the heat resistance (Waermeformbestaendigkeit) and an increase in the stiffness (elastic modulus) above the glass transition temperature. However, only partial crosslinking should also be included in the term "crosslinking". Only partial crosslinking may be present if not enough crosslinking agent was used to completely integrate all the PAEK chains into the network. In this case, the material usually has a higher elongation at break than a fully crosslinked material. The imine bonds give the molded article high stability. According to the invention, the molded article is preferably a PAEK-based molded article. By "PAEK-based" is meant that the PAEK is the essential structure-imparting polymeric component of the molded article. In one embodiment, it is preferred that the PAEK is the only polymeric component of the molded article.

[0094] The crosslinking agents usable according to the invention have relatively high melting and boiling points, so that the temperature in step (iii) can be set relatively high, which is advantageous since such crosslinking reactions are generally accelerated at high temperatures, but advantageously this temperature is below the melting region of the PAEK and below the softening point of the moulded part which is not yet fully crosslinked.

[0095] Surprisingly, it was found that in the system according to the invention the crosslinking reaction already occurs below the melting region of the polymer and of the molded article, which was unexpected since it is generally believed that the crosslinking reaction only occurs at temperatures above the melting region of the polymer and of the molded article.

[0096] However, according to the invention, it has been found that the crosslinked PAEK can have particularly advantageous properties if the heating of the molded article in step (iii) is advantageously carried out for a period of at least 1 minute, for example 6 hours to 30 days. It has been found that the thermal and mechanical stability can be substantially improved by such a heat treatment. Crosslinking can be carried out at temperatures considerably higher than the melting temperature of the PAEK in the case of coatings, whereby very short reaction times are sufficient. Also, in the case of solid molded articles from mixtures with a high fiber and / or filler content, which retain their shape even beyond the melting region of the PAEK, the crosslinking time can be significantly shortened by the corresponding high crosslinking temperature. In the case of more brittle molded articles, which may deform during post-heating, the post-heating temperature must be selected so that the molded article is even further below the melting temperature of the material, which can result in significantly longer post-heating times of up to 30 days.

[0097] In particular, it has been found that heat treatment can improve the stiffness of samples at high temperatures. It has been observed that heat treatment for a certain period of time can improve stiffness significantly, followed by saturation, so that further thermal post-treatments do not improve stiffness or only slightly. However, further thermal post-treatments usually improve thermal resistance. It has been found that the thermal resistance can also increase with longer thermal post-treatments, so that significant improvements can still be observed after several days.

[0098] Preferably, the heat treatment in step (iii) is carried out with the exclusion of oxygen.

[0099] The moulded article is cooled after crosslinking and can be supplied for its use or can be further processed.

[0100] If desired, the molded article can be subjected to treatment in the presence of an oxygen-containing gas during and / or after the heat treatment in step iii). Thus, the surface hardening of the crosslinked PAEK can be carried out by suitable oxidation of the crosslinked material. For this purpose, after the crosslinking step carried out in a protective gas atmosphere, for example, the molded article can be subjected to post-heating in air. Alternatively or additionally, a certain amount of oxygen can be metered in during the post-crosslinking step iii).

[0101] As mentioned above, both the mixture in step (i) and the moulded article can contain fillers and reinforcing agents and / or optionally other additives, in which case the crosslinked PAEK forms a matrix in which the optionally present fillers and reinforcing agents and / or additives are homogeneously distributed.

[0102] Suitable fillers and reinforcing agents are selected from among glass fibers, e.g. in the form of woven glass, glass mat, nonwoven glass, glass silk roving or cut glass silk, wollastonite, calcium carbonate, glass beads, quartz powder, silicon nitride and boron nitride, amorphous silica, asbestos, magnesium carbonate, calcium silicate, calcium metasilicate, kaolin, mica, feldspar, talc and mixtures thereof.

[0103] Suitable additives are selected from among antioxidants, UV and heat stabilizers, lubricants and release agents, colorants such as dyes and pigments, nucleating agents, plasticizers and mixtures thereof.

[0104] For example, fillers and reinforcing agents can be used in an amount of up to 80% by weight, such as 0.1% to 80% by weight, specifically 1% to 60% by weight, based on the total weight of the components used to produce the molded article.

[0105] For example, the additives may be used in amounts of up to 30% by weight, such as 0.1% to 20% by weight, each based on the total weight of the components used to produce the molded article.

[0106] The subject of the present invention is also a molding based on polyaryletherketone (PAEK) and having a crosslinked matrix from PAEK, the PAEK being crosslinked with a diamine source as defined above. In particular, the subject of the present invention is a molding obtained according to the process according to the present invention.

[0107] In particular, molded articles are obtained by the method according to the invention as described in the context of the present invention. The molded articles preferably have the advantageous properties as described in the context of the present invention for crosslinked PAEK. The term molded article in the context of the present invention refers to a product from crosslinked PAEK with a defined three-dimensional shape. In this case, the molded article does not have to be a defined object, but can be, for example, a coating. The molded article can be made of or contain crosslinked PAEK, for example as a composite or laminate.

[0108] It may be desirable not to completely crosslink the polymer in the molded article, since the elongation at break of the material may decrease as crosslinking increases. Therefore, the degree of crosslinking is preferably set in light of the desired application, for example, via the proportion of crosslinker and the type and time of heat treatment.

[0109] The degree of crosslinking is preferably not measured directly, but whether the molded article has the desired properties is confirmed by appropriate test methods, such as, for example, high temperature tensile tests and measurements of dynamic modulus.

[0110] The mouldings can be used in particular in technical fields where high thermal resistance and mechanical stability, in particular high rigidity, are required. The mouldings are particularly suitable for use as sealing articles for electrical or chemical applications, in particular as sealing rings and O-rings, bushes, bearings, back-up rings, valves, thrust washers, snap hooks, pipes or wires, cables, jackets and sheaths, casings or components thereof. The mouldings are particularly suitable for uses where high chemical and abrasion resistance is required. This applies in particular in the food and packaging industry and medical technology, oil and gas conveying, aerospace technology and the chemical industry, as well as in the manufacture of safety-related parts, in the energy production sector and in the automotive industry. Also possible applications are connectors and insulators in the electronics sector, since good insulating properties are obtained by crosslinking. The subject of the invention is also a sealing article which consists of or contains a moulding according to the invention. This sealing article can be used for static or dynamic applications, in particular for dynamic applications exposed to high mechanical loads. In particular, the sealing article is suitable for sealing applications in contact with fluids, such as lubricants, and exposed to high temperatures, for example in the range above 150° C., particularly 180° C. up to decomposition.

[0111] The method, the moldings and the sealing articles according to the invention solve the problem underlying the invention. They have high heat resistance and high mechanical stability combined with good processability. In particular, the moldings have a high glass transition temperature and high stiffness. The high stiffness is accompanied by a reduction in creep behavior at high temperatures. The improved heat resistance is evident both at the maximum temperature and at the continuous use temperature, especially in the range from 150°C to decomposition. The moldings show advantageous rubber-elastic behavior in the high temperature range. In this case, the products show very good chemical resistance and reduced flammability, since the material does not melt due to crosslinking and the flammable material does not drip off even at low wall thicknesses.

[0112] Furthermore, the molded articles according to the invention can be produced simply and efficiently by thermoplastic shaping methods. For example, production can be carried out by simple extrusion. The method can also be carried out in an environmentally friendly manner and without endangering the user, since the crosslinking agents used have a relatively high boiling point and are not very volatile.

[0113] The present invention will now be described with reference to the following examples but is not limited to the specifically described embodiments. [Brief description of the drawings]

[0114] [Figure 1] FIG. 1 shows the change in the complex dynamic modulus with increasing temperature of a molded article according to the invention in comparison with various reference materials used in the same field, in which commercially available thermoplastics such as PEEK under the trademark Ketaspire (1), PEK from Gharda Plastics (2), PAI under the trademark Torlon (3), and TPI under the trademark Dexnyl (4) are used as reference materials, and furthermore, PEEK crosslinked with 1.05% DAPI, crosslinked by thermal post-treatment as described in WO 2020 / 030599, is shown as a reference (5), and as molded articles according to the invention, samples of PEEK under the trademark Ketaspire modified and crosslinked with 1% and 6% PA4.T (6 and 7), modified and crosslinked with PA6.T (8), and modified and crosslinked with 3% aminated fatty acid dimer (9) are shown, all samples were produced without fillers, reinforcing agents or other additives. [Figure 2a] FIG. 1 illustrates a sample coupon containing crosslinked and non-crosslinked PEEK. [Figure 2b] FIG. 1 shows sample coupons containing crosslinked and non-crosslinked PEEK after two weeks of storage in sulfuric acid. [Figure 3a] FIG. 1 shows test results for rheological testing, where the respective storage modulus G′ (in Pa) and the respective loss modulus G″ (in Pa) of the samples are plotted logarithmically on the Y-axis and the test time (in minutes) on the X-axis. [Figure 3b] FIG. 1 shows test results for rheological testing, where the respective storage modulus G′ (in Pa) and the respective loss modulus G″ (in Pa) of the samples are plotted logarithmically on the Y-axis and the test time (in minutes) on the X-axis. [Figure 3c] FIG. 1 shows test results for rheological testing, where the respective storage modulus G′ (in Pa) and the respective loss modulus G″ (in Pa) of the samples are plotted logarithmically on the Y-axis and the test time (in minutes) on the X-axis. [Figure 3d] FIG. 1 shows test results for rheological testing, where the respective storage modulus G′ (in Pa) and the respective loss modulus G″ (in Pa) of the samples are plotted logarithmically on the Y-axis and the test time (in minutes) on the X-axis. [Figure 3e] FIG. 1 shows test results for rheological testing, where the respective storage modulus G′ (in Pa) and the respective loss modulus G″ (in Pa) of the samples are plotted logarithmically on the Y-axis and the test time (in minutes) on the X-axis.

[0115] Starting materials: PEEK Solvay KetaSpire PEEK PEK Gharda PAEK 1200 PAI Polyamide-imide manufactured by Solvay under the trademark Torlon TPI Dexnyl Polyimide PPA1 PA4.T PPA2 PA6.T AA Aminated fatty acid dimer DAPI 1-(4-aminophenyl)-1,3,3-trimethyl-indan-5-amine (CAS number 54628-89-6)

[0116] Example 1 PEEK was mixed with different amounts of crosslinker (see Table 1) and compounded in a twin-screw compounder with the lowest possible melt temperature and short residence time. The strands were cooled and subsequently granulated. The resulting granulate was subsequently dried and processed into sample pieces in an injection moulding machine under the most gentle possible conditions.

[0117] After injection molding, the sample pieces were post-conditioned in an oven. DMA sample pieces with dimensions of 45 mm x 4 mm x 2 mm are prepared from the reheated sample rods of ISO standard 527 type 1A. The sample pieces are subsequently characterized by DMA temperature sweep (Figure 1).

[0118] TIFF0007657933000003.tif57132

[0119] Dynamic mechanical analysis (DMA) Dynamic Mechanical Analysis (DMA) is a thermal method for measuring the physical properties of synthetic resins. A temperature gradient (temperature sweep) shows the change in dynamic modulus and therefore stiffness in the measured temperature range. Among other things, the glass transition region (Tg), the height of the plateau above Tg, the position of the drop in modulus when the crystalline phase melts, and the height of the plateau in the high temperature range are of particular interest here.

[0120] DMA was performed using mouldings according to the above examples (see Table 1). Temperature gradients were measured using sample piece strips (width approx. 4 mm, thickness approx. 2 mm, sample length 45 mm, clamp length during testing approx. 20 mm) under the following conditions: heating rate 3 K / min, contact force 0.5 N, strain amplitude + / - 0.1%. The results are graphically shown in Figure 1.

[0121] The results show that PEEK crosslinked according to the invention has advantageous thermal properties. All molded parts according to the invention have a significant increase in glass transition temperature (Tg) compared to unmodified PEEK. PEEK crosslinked with aminated fatty acid dimer shows the highest increase compared to PEEK, and the PPA crosslinked PEEK sample shows a glass transition region between aminated fatty acid dimer crosslinked PEEK and DAPI crosslinked PEEK.

[0122] Between the glass transition and melting regions, the samples show an increase in the plateau height that decreases with increasing temperature, resulting in a more or less pronounced increase in the melting temperature region of the crystalline phase. In this region, the modulus height is inversely proportional to the concentration of the crosslinkable PPA.

[0123] Furthermore, the formation of a rubber plateau above the melting zone of the crystalline regions prevents plastic deformation up to the decomposition zone of the moulded parts made of this material, which is also significantly increased for moulded parts according to the invention compared to PEEK crosslinked with DAPI, resulting in an overall higher heat resistance.

[0124] The results also show that by combining not only PPA but also aminated fatty acid dimer with PEEK, optimal product properties can be achieved in terms of increased glass transition range, high elastic modulus and high thermal resistance, which allows significantly improved service conditions for products made from this material.

[0125] By extending the heat treatment, the thermal properties can be improved even more significantly.

[0126] This allows for a wider temperature application window compared to PAI, TPI, non-crosslinked PEEK, and even PEEK crosslinked with DAPI.

[0127] Example 2 To estimate the crosslink density, a swelling test is carried out in concentrated sulfuric acid. Non-crosslinked PEEK dissolves in concentrated sulfuric acid, while crosslinked PEEK swells more or less depending on the crosslink density. The less the sample swells, the higher the crosslink density. In the experiment, samples with dimensions of approximately 10 x 4 x 3 mm were cut from the test rods produced by injection molding and placed in glass. 20 ml of concentrated sulfuric acid was added to each sample at room temperature, and the whole was left to stand at room temperature conditions. After about a week, the samples were gently shaken several times by hand and the results were evaluated after two weeks.

[0128] sample: 1. PEEK + 1.05% DAPI PEEK containing 2.6% PPA (untreated) 3.1% PPA-containing PEEK (tempered) PEEK containing 4.3% PPA (tempered) PEEK containing 5.6% PPA (tempered)

[0129] The results can be seen in Figure 2.

[0130] 1. The DAPI crosslinked sample on the left shows a large volume increase due to swelling, but is not soluble. 2. The PEEK with 6% PPA that was not thermally post-treated in the second position is completely dissolved, indicating that no crosslinking has yet occurred. The post-conditioned PEEK with 3.1% PPA shows obvious swelling. The PEEK mixed with 4.3% PPA and post-conditioned only swelled slightly after two weeks of storage in sulfuric acid, indicating a fairly high crosslink density. It can be concluded that the PEEK mixed with 5.6% PPA and post-conditioned exhibits almost no swelling and has a fairly high crosslink density.

[0131] Example 3 In addition to dynamic mechanical analysis and swelling, rheological tests showing the chemical post-crosslinking of PAEK with different crosslinkers were carried out on an Anton Paar rheometer type MCR-302. Two reference materials and three materials according to the invention (PEEK, PEEK with 1.05% DAPI, PEEK with 6% PPA, PEEK with 3% PPA and PEEK with 3% AA) were processed by injection molding into 2 mm test plates from which test specimens were fabricated for measurement in the rheometer. The material disks were bonded between plane-parallel plates of the same diameter in the rheometer and the measuring unit was heated to the test temperature.

[0132] The test conditions are shown in Table 3.

[0133] TIFF0007657933000004.tif52146

[0134] The test results are shown in Figures 3a-e. The respective storage modulus G' (in Pa) and respective loss modulus G'' (in Pa) of the three samples are shown logarithmically on the Y-axis. The test time (in minutes) is plotted on the X-axis.

[0135] The storage modulus G' is a measure of the mechanical energy stored by a material when sheared. The loss modulus G'' indicates the energy dissipated by the material during a shear experiment. Liquids cannot store mechanical energy during a shear experiment; therefore, their storage modulus is approximately zero. For viscoelastic materials, part of the energy is stored and another part is dissipated. For solids, the storage modulus G' is usually much larger than the loss modulus G''.

[0136] In Figure 3a it can be seen that the storage modulus G' of PEEK settles to about 250 Pa after the equilibration run-in phase. The loss modulus G'' is about 2830 Pa and remains constant over the rest of the test period. The non-crosslinked sample behaves like a typical viscoelastic fluid in the molten state.

[0137] Observing the sample from PEEK with 1.05% DAPI in Figure 3b, it can be seen that the storage modulus increases faster than the loss modulus and that after 15 min the two curves intersect, which defines the gel point and therefore represents the transition to the solid state.

[0138] Figure 3c shows the behavior of PEEK after the addition of 6% PPA, which reaches its gel point as early as about 12 min at this concentration.

[0139] As shown in Figure 3 d, when 3% PPA is used on PEEK, crosslinking occurs approximately 30 min after the sample begins to melt, which can be seen from the intersection of the storage modulus measurement curve and the loss modulus measurement curve.

[0140] With 3% aminated fatty acid dimer, an initial softening of the sample after melting is followed by an increase in the storage and loss moduli, which then initiates crosslinking and similarly reaches the gel point after about 30 min, as can be seen from the intersection of the loss and storage moduli in Figure 3 e.

Claims

1. 1. A molded article with a matrix resulting from the reaction of a polyaryletherketone (PAEK) with at least one crosslinker capable of thermally crosslinking with the keto groups of the PAEK to form at least two imine groups per crosslinker molecule, At least one of the crosslinking agents is a) polyamides selected from among PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T and mixtures thereof; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof is selected from among The amount of the crosslinking agent is 0.1 to 10% by mass, based on the total weight of the crosslinking agent and the polyaryletherketone.

2. 2. The molded article of claim 1, further comprising at least one filler and reinforcing agent and / or at least one additive different therefrom.

3. 3. The molded article according to claim 1 or 2 in the form of a coating.

4. 1. A method for producing a molded article, comprising the steps of: i) preparing a mixture containing at least one polyaryletherketone and at least one crosslinker, At least one of the at least one crosslinking agent is a) polyamides selected from among PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T and mixtures thereof; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof is selected from among the amount of the crosslinking agent is 0.1 to 10% by weight based on the total weight of the crosslinking agent and the polyaryletherketone; ii) producing a molded article from the mixture obtained in step i); iii) heat treating the molded article at a temperature at which the polyaryletherketone is crosslinked; A method comprising:

5. 5. The method according to claim 4, wherein in step i) said at least one polyaryletherketone and said at least one crosslinking agent are subjected to melt mixing and / or dry mixing.

6. The method described in claim 5, wherein in step i), the at least one polyaryletherketone, the at least one crosslinking agent, and fillers and reinforcing agents, and / or at least one further additive different therefrom, are melt-mixed and / or dry-mixed.

7. 5. The method according to claim 4, wherein in step i) the at least one polyaryletherketone and the at least one crosslinking agent are fed to an extruder and mixed in a plasticized state.

8. The method of claim 7, wherein in step i), the at least one polyaryletherketone, the at least one crosslinking agent, and fillers and reinforcing agents, and / or at least one further additive different therefrom, are fed to an extruder and mixed in a plasticized state.

9. The crosslinker prepared in step i) contains at least 20% by weight, based on the total weight of the crosslinker, of a) polyamides selected from among PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T and mixtures thereof; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof The method according to any one of claims 4 to 8, wherein the compound is selected from the group consisting of

10. The crosslinker prepared in step i) contains at least 50% by weight, based on the total weight of the crosslinker, a) polyamides selected from among PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T and mixtures thereof; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof The method of claim 9, wherein the compound is selected from the group consisting of

11. The crosslinker prepared in step i) contains at least 80% by weight, based on the total weight of the crosslinker, a) polyamides selected from among PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T and mixtures thereof; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof The method of claim 9, wherein the compound is selected from the group consisting of

12. The crosslinker prepared in step i) contains at least 90% by weight, based on the total weight of the crosslinker, a) polyamides selected from among PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T and mixtures thereof; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof The method of claim 9, wherein the compound is selected from the group consisting of

13. The crosslinker prepared in step i) comprises at least 99% by weight, based on the total weight of the crosslinker, a) polyamides selected from among PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T and mixtures thereof; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof The method of claim 9, wherein the compound is selected from the group consisting of

14. 14. The method of any one of claims 4 to 13, wherein at least one of the crosslinking agents is a saturated alicyclic compound having at least two primary amino groups selected from aminated dimeric fatty acid, oligomers / polymers containing aminated dimeric fatty acid as copolymerized units, and mixtures thereof.

15. At least one of the crosslinkers is a compound; 【Chemistry 1】 15. The method according to claim 14, wherein the compound is an oligomer / polymer containing the compound as a copolymerized unit.

16. 16. The method of claim 4, wherein the polyaryletherketone is polyetherketone (PEK), polyetheretherketone (PEEK) or polyetheretheretherketone (PEEEK).

17. 17. The process of any one of claims 4 to 16, wherein the mixture does not contain an added solvent.

18. 18. The method of any one of claims 4 to 17, wherein the temperature in step iii) is at least 300°C.

19. 19. The method according to any one of claims 4 to 18, wherein the mixture in step ii) is processed by extrusion, hot pressing, injection moulding and / or additive manufacturing methods.

20. 20. The method according to any one of claims 4 to 19, wherein the shaped article is subjected to a treatment in the presence of an oxygen-containing gas during and / or after the heat treatment in step iii).

21. A polymer mixture containing at least one polyaryletherketone (PAEK) and at least one crosslinker, At least one of the at least one crosslinking agent is a) polyamides selected from among PA4.T, PA5.T, PA6.T, PA9.T, PA8.T, PA10.T, PA12.T and mixtures thereof; b) a saturated alicyclic compound different from a) having at least two primary amino groups; and mixtures thereof is selected from among The amount of the crosslinking agent is 0.1 to 10% by weight, based on the total weight of the crosslinking agent and the polyaryletherketone.

22. 4. Use of a molded article as defined in any one of claims 1 to 3 in the fields of automotive, maritime, aerospace, rail vehicles, oil and gas industry, food and packaging industry and medical technology.

23. Sealing articles for electrical or chemical applications, thrust washers, back-up rings, valves, connectors, insulators, snap hooks, bearings, bushings, films, powders, coatings, fibres, seal rings and O-rings, pipes and lines, cables, jackets and sheaths, casings, consisting of or comprising a moulded article as defined in any one of claims 1 to 3.

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