Aqueous solution of a lactam of lignin

Abstract

Use of an aqueous lactam solution as a solvent, the aqueous lactam solution having a lactam content of 50 to 95 wt.-%, based on the total weight of water and lactam in the solution.

Description

[0001] The present invention relates to an aqueous solution of lactam, which preferably contains lignin.

[0002] The present invention further relates to the use of aqueous lactam solutions as solvents, preferably for lignin. Furthermore, the present invention relates to the use of such solutions for producing homogeneous polyamide / lignin mixtures, methods for producing such mixtures, including thermoplastic molding compositions of these mixtures, their uses, and molded articles, fibers, and foils made therefrom.

[0003] Lignin is one of the most abundant biopolymers in nature. Although obtained primarily as a byproduct of pulp production, it is rarely used as a valuable raw material for obtaining basic chemicals or (functional) materials. One of the major obstacles to lignin processing is its inherently poor solubility in most solvents. In particular, aqueous solvents cannot dissolve large amounts of lignin (e.g., >10 wt%) unless strongly alkaline conditions are applied. Precipitation occurs once the pH decreases. Efficient dissolution of lignin (e.g., >10 wt%) can be achieved using toxic organic solvents (e.g., pyridine and methylimidazole) or expensive ionic liquids. To develop new methods and strategies for utilizing lignin as an attractive raw material, a simple, cost-effective, and non-toxic solvent system for dissolving lignin is needed.

[0004] Lignin polymer compounds or composites are well known. Generally, polydisperse lignin powder is added to thermoplastic base polymers such as polyamides during melt mixing. The properties of the resulting lignin-polymer (lignin-polyamide) composite depend primarily on the compatibility of the materials used and the resulting homogeneity. However, due to its heterogeneous structure, lignin tends to be incompatible with most industrially relevant thermoplastic polymers, leading to poor application performance. Therefore, a new method is needed to simply produce homogeneous lignin-polymer mixtures.

[0005] WO 2009 / 153204 A1 relates to compositions comprising a polyamide matrix and lignin. For example, lignin obtained by the Organosolv method is added to polyamide 66 in powder form by extrusion. Lignin has been found to inhibit water absorption by the polyamide. Furthermore, lignin is said to act as an antiplasticizer, enhance the rigidity of the polyamide matrix, and have a fluidizing effect on the polyamide matrix. 1-15% by weight of lignin may be added to the composition.

[0006] It is claimed that by using lignin in polyamide compositions, the water absorption rate of the composition can be reduced, thereby stabilizing dimensional stability without affecting mechanical properties. The lignin is added in powder form.

[0007] Olav Müller described the chemical properties of lignin in *Die Angewandte Makromolekulare Chemie* 52 (1976) 85-99 (no. 759). Müller found that when attempting to polymerize beech lignin sulfate in a caprolactam melt, a light brown material with a metallic glaze was obtained. However, even with a lignin content below 1%, its fiber-forming properties were significantly affected. It was claimed that even the addition of 0.5% lignin hindered fiber formation during extrusion and spinning. When beech lignin was added to the caprolactam melt, complete dissolution was achieved at 1% by weight. When 5%, 10%, or 20% beech lignin was added, an inhomogeneous melt was obtained from which fibers could not be produced.

[0008] VIVrublevskaya and LANikitchenko, in J. Appl. Chem. USSR (Engl. Transl.), edited by Plenum Publishing Corporation, pp. 1666–1669, 1982, ISSN: 0021-888X (Zhurnal Priklad-noi Khimii, vol. 54, no. 8, 1908–1911, August 1981), describe methods for modifying wood using various types of ε-caprolactam. The authors modify wood by filling it with a melt of ε-caprolactam followed by polymerization, resulting in the polymerization of ε-caprolactam in a porous capillary wood system. Anionic and hydrolyzed ε-caprolactam polymerization were used, but anionic polymerization led to chemical degradation of the wood system, causing a decrease in thermal stability and strength properties and an increase in swelling. The mixture of hydrolyzed polymers showed the formation of a new substance that is more heat-resistant than lignin, as its thermal decomposition only begins at 230°C.

[0009] The object of the present invention is to provide a homogeneous polyamide / lignin mixture and a lignin solution capable of forming a homogeneous polyamide / lignin mixture.

[0010] The objective of this invention is to use an aqueous solution of lactam with a lactam content of 50 to 95% by weight (based on the total weight of water and lactam in the solution) as a solvent.

[0011] The objective of this invention can also be achieved by using an aqueous solution of lactam with a lactam content of 50 to 95% by weight (based on the total weight of water and lactam in the solution).

[0012] The object of the present invention is further achieved by using an aqueous solution of lactam having a lactam content of 50 to 95% by weight (based on the total weight of water and lactam in the solution) and further comprising 0.1 to 40% by weight of a crosslinked phenolic polymer, preferably lignin (based on the amount of lactam in the solution), to produce a homogeneous polyamide / lignin mixture.

[0013] The present invention also relates to a method for producing a homogeneous polyamide / lignin mixture, comprising the step of ring-opening polymerization of an aqueous lactam in an aqueous solution, wherein water is removed, the aqueous solution initially comprising water and 50 to 95% by weight of lactam based on the total weight of water and lactam in the solution, and further comprising 0.1 to 40% by weight of a crosslinked phenolic polymer, preferably lignin, based on the amount of lactam in the solution.

[0014] Furthermore, the present invention relates to a thermoplastic molding composition comprising...

[0015] a) A homogeneous polyamide / lignin mixture of 40 to 100 wt% as component A, wherein the mixture contains 0.1 to 40 wt% lignin based on the amount of polyamide, wherein the polyamide comprises polymerized lactam units.

[0016] b) 0 to 10% by weight of polyamide without polymeric lactam units, as component B.

[0017] c) 0 to 45% by weight of at least one elastic polymer, as component C,

[0018] d) 0 to 60% by weight of at least one fibrous and / or particulate filler, as component D,

[0019] e) 0 to 25% by weight of further additives, as component E,

[0020] The total weight percentage of components A to E is 100% by weight.

[0021] Furthermore, the present invention also relates to the use of such thermoplastic molding compositions for forming molded articles, fibers or foils.

[0022] Finally, the present invention also relates to molded articles, fibers or foils made from such thermoplastic molding compositions.

[0023] This invention allows for the efficient dissolution of lignin in non-toxic and inexpensive solvents, which are also used to subsequently form a polyamide matrix. According to existing technologies, the dissolution of lignin is achieved using toxic solvents or expensive ionic liquids.

[0024] This invention overcomes the problem of frequent incompatibility between lignin and polyamide compounds. This invention allows for the formation of homogeneous lignin / polyamide mixtures or complexes.

[0025] Therefore, lignin can be incorporated very uniformly into polyamide polymers using simple methods, for example, to increase bio-based content and reduce the carbon footprint of polyamide products. Furthermore, the advantages mentioned in WO 2009 / 153204 A1 may also be achievable.

[0026] According to the present invention, an aqueous solution of caprolactam, preferably an aqueous solution of ε-caprolactam, having a caprolactam content of 50 to 95% by weight, is found to be an organic compound, preferably a cross-linked phenolic polymer, and more preferably a good solvent for lignin.

[0027] In the context of this invention, "caprolactam" generally refers to "ε-caprolactam".

[0028] Lignin is a complex organic polymer that forms a crucial structural material in the supporting tissues of vascular plants and some algae. Lignin is essential for cell wall formation, particularly in wood and bark. It makes wood and bark hard and resistant to decay. Chemically, lignin is a cross-linked phenolic polymer. In particular, lignin is a high-molecular-weight aromatic compound found in plants, comprising hydroxylated and methoxylated phenylpropene units, such as 4-hydroxycinnamyl alcohol (p-cumaryl alcohol), coniferyl alcohol, and / or sinapyl alcohol (so-called elemental alcohols). These monomer units can be linked together through different types of linkages.

[0029] Lignin can be obtained by, for example, the sulfate method (Kraft lignin), the soda method, and / or the organic solvent method (Organosolv) (organic solvent lignin). Methods for obtaining lignin are described, for example, in US4507172, CA2256923, EP3156409, WO2013 / 070130, DE3901662, WO2012 / 027767, and / or WO2006 / 038863. Lignin can also be obtained by acidification and filtration (e.g., via LignoBoost as described in US20170355723). TM Lignin can be extracted as a lignin solid from the "black liquor" stream of the Kraft pulp mill using methods or equivalent methods. Lignin can also be obtained by enzymatic hydrolysis (WO2020144115, EP3743514).

[0030] Lignin, a component of plants, is typically obtained in mixtures with cellulose or hemicellulose materials. Several methods exist for separating lignin from cellulose / hemicellulose composites. One example of a commercially used method is the Kraft process, applied in the paper industry, where the resulting lignin is a byproduct or waste. As an alternative method, lignin extraction can be employed, as described on pages 4 and 5 of WO 2009 / 153204.

[0031] The lignin used in this invention is preferably derived from hardwoods (such as eucalyptus), softwoods (such as spruce and / or pine), grass, straw and / or other biomass.

[0032] Lignin is a well-known, poorly soluble biopolymer. Many attempts have been made to find suitable solvents to dissolve lignin. Commonly used solvents include toxic organic solvents (DMSO, pyridine), expensive ionic liquids, deep eutectic solvent mixtures, or aqueous mixtures of ionic liquid / water or organic solvent / water. However, solvent systems using aqueous caprolactam solutions have not yet been described. Therefore, the research results described below represent a novel method for dissolving lignin.

[0033] The solvent system used to dissolve lignin is an aqueous solution of lactam, preferably an aqueous solution of ε-caprolactam, based on the total weight of water and lactam in the solution, wherein the (caprolactam) content is 50 to 95% by weight, preferably 75 to 95% by weight, more preferably 78 to 87% by weight, for example about 80% by weight of caprolactam.

[0034] According to the present invention, the pH value of the aqueous solution is preferably in the range of 1 to 14, more preferably 3 to 10, and most preferably 5 to 8.

[0035] An aqueous solution of caprolactam at the above concentration is an ideal solvent for lignin, which can be added at ambient temperature or under varying temperatures. Typically, lignin dissolves in the solvent system at room temperature (20 to 25°C). Lignin is preferably used in powder form for ease of dissolution.

[0036] The aqueous solution of lignin (caprolactam) is preferably free of or free of (further) organic solvents such as DMSO or pyridine, ionic liquids and eutectic solvent mixtures.

[0037] Preferably, the caprolactam aqueous solution contains only water and caprolactam. The amount of additives such as surfactants or colorants is preferably 0 to 5% by weight, more preferably 0 to 2% by weight, and even more preferably 0 to 1% by weight, based on the total weight of the solution. Therefore, it is preferred that the caprolactam aqueous solution used as a solvent system consists of water, 50 to 95% by weight of caprolactam, and 0 to 5% by weight of additives, based on the total weight of the solution. The preferred amounts described above apply.

[0038] If necessary or required, pH adjusters can be added to adjust the pH of the caprolactam aqueous solution, or to make it neutral (pH = 5 to 8). Typically, small amounts of inorganic or organic acids or bases, or buffers, can be used to achieve the desired pH or neutrality of the solution. These pH adjusters can also be considered as part of the additives mentioned above.

[0039] (Caprolactam) aqueous solutions can be used as solvents, preferably for organic compounds, more preferably for cross-linked phenolic polymers, especially lignin.

[0040] The lactam used in aqueous solutions is preferably selected from C 4-13 lactam, more preferably C 6-10 Lactams. Examples of these include caprolactam, octyllactam and laurolactam, pyrrolidone, glycolactam, 9-aminononanoic acid, and 11-aminoundecanoic acid.

[0041] ε-caprolactam is the most preferred. A mixture of ε-caprolactam and a small amount of other lactams may also be used. In this case, based on the total amount of lactams in the solution, the amount of lactams other than ε-caprolactam is preferably 0 to 20% by weight, more preferably 0 to 10% by weight, and most preferably 0 to 5% by weight.

[0042] As component A, the thermoplastic molding material may include at least one copolyamide produced by polymerization of the following components:

[0043] A') 15 to 84% by weight of at least one lactam,

[0044] B') 16 to 85% by weight of a monomer mixture (M), which consists of the following components:

[0045] B1') at least one C 32 -C 40 dimer acids, and

[0046] B2') at least one C4-C 12 diamine,

[0047] The weight percentages of components A') and B') in each case are based on the sum of the weight percentages of components A') and B') in each case.

[0048] In the context of this invention, the terms "component A'" and "at least one lactam" are synonymous and therefore have the same meaning.

[0049] This also applies to the terms "component B'" and "monomer mixture (M)". These terms are used synonymously in the context of this invention and therefore have the same meaning.

[0050] According to the invention, at least one copolyamide is polymerized by 15 to 84 wt% of component A') and 16 to 85 wt% of component B'), preferably by 40 to 83 wt% of component A') and 17 to 60 wt% of component B'), particularly preferably by 60 to 80 wt% of component A') and 20 to 40 wt% of component B'), wherein the weight percentages of components A') and B') are each based on the sum of the weight percentages of components A') and B').

[0051] The sum of the weight percentages of components A') and B') is preferably 100% by weight.

[0052] It is understood that the weight percentages of components A') and B') are related to their weight percentages before polymerization, i.e., before they have reacted with each other. During the polymerization of components A') and B'), the weight ratio of components A') and B') can be optionally changed.

[0053] According to the present invention, at least one copolyamide is produced by the polymerization of components A') and B'). The polymerization of components A') and B') is known to those skilled in the art. The polymerization of components A') and B') is generally a condensation reaction. In the condensation reaction, component A') reacts with components B1') and B2') present in component B'), and optionally with component B3') described below, which may also be present in component B'). This results in the formation of amide bonds between the components. During the polymerization process, component A') is generally at least partially in an open-chain state, i.e., in the form of amino acids.

[0054] The polymerization of components A') and B') can be carried out in the presence of a catalyst. Suitable catalysts include all catalysts known to those skilled in the art that can catalyze the polymerization of components A') and B'). Such catalysts are known to those skilled in the art. Preferred catalysts are phosphorus compounds, such as sodium hypophosphite, phosphoric acid, triphenylphosphine, or triphenyl phosphite.

[0055] The polymerization of components A') and B') forms at least one copolyamide, which thus comprises units from component A') and units from component B'). The units from component B') include units from components B1') and B2'), and optionally units from component B3').

[0056] The polymerization of components A') and B') forms a copolyamide as a copolymer. This copolymer can be a random copolymer. It can also be a block copolymer.

[0057] In block copolymers, blocks formed are composed of units from component B') and units from component A'). They appear in an alternating order. In random copolymers, units from component A') alternate with units from component B'). This alternation is random. For example, two units from component B') may be followed by a unit from component A'), then another unit from component B'), and then a unit containing three units from component A').

[0058] This is preferred when at least one copolyamide is a random copolymer.

[0059] The production of at least one copolyamide preferably includes the following steps:

[0060] I) Polymerize components A') and B') to obtain at least one first copolyamide.

[0061] II) Granulate at least one first copolyamide obtained in step I) to obtain at least one granulated copolyamide.

[0062] III) Extract at least one granulated copolyamide obtained in step II) with water to obtain at least one extracted copolyamide.

[0063] IV) at temperature (T) T The copolyamide obtained in drying step III) is used to obtain at least one copolyamide.

[0064] The polymerization in step I) can be carried out in any reactor known to those skilled in the art. Stirred tank reactors are preferred. Auxiliaries known to those skilled in the art, such as defoamers like polydimethylsiloxane (PDMS), can also be used to improve re-reaction management.

[0065] In step II), at least one first copolyamide obtained in step I) can be granulated by any method known to those skilled in the art, such as wire granulation or underwater granulation.

[0066] The extraction in step III) can be performed by any method known to those skilled in the art.

[0067] During the extraction process in step III, the byproducts formed during the polymerization of components A') and B') in step I) are typically extracted from at least one granulated copolyamide.

[0068] In step IV), at least one extracted copolyamide obtained in step III) is dried. The drying method is known to those skilled in the art. According to the present invention, at least one extracted copolyamide is dried at a temperature (T). TDrying is carried out at a temperature (T). T Preferably, the glass transition temperature (T) is higher than that of at least one copolyamide. G(C) And below the melting temperature (T) of at least one copolyamide. M(C) ).

[0069] The drying in step IV) is usually carried out in the range of 1 to 100 hours, preferably in the range of 2 to 50 hours, and particularly preferably in the range of 3 to 40 hours.

[0070] It can be assumed that the drying in step IV) further increases the molecular weight of at least one copolyamide.

[0071] At least one copolyamide—without component B—typically has a glass transition temperature (T0). G(C) Glass transition temperature (T) G(C) For example, in the range of 20°C to 50°C, preferably in the range of 23°C to 47°C, and particularly preferably in the range of 25°C to 45°C, as determined according to ISO 11357-2:2014.

[0072] In the context of this invention, according to ISO 11357-2:2014, the glass transition temperature (T) of at least one copolyamide is... G(C) ) is based on the glass transition temperature (T) of dry copolyamide. G(C) ).

[0073] In the context of this invention, "dry" should be understood to mean that at least one copolyamide contains less than 1% by weight, preferably less than 0.5% by weight, particularly preferably less than 0.1% by weight of water, based on the total weight of at least one copolyamide. "Dry" is more preferably understood to mean that at least one copolyamide does not contain water, and most preferably, at least one copolyamide does not contain solvent.

[0074] In addition, at least one copolyamide typically has a melting temperature (T0). M(C) The melting temperature (T) of at least one copolyamide M(C) For example, in the range of 150 to 210°C, preferably in the range of 160 to 205°C, and particularly preferably in the range of 160 to 200°C, as determined according to ISO 11357-3:2014.

[0075] Viscosity number (VN) of at least one copolyamide (C) The viscosity number is typically in the range of 150 to 300 ml / g, determined by a 0.5% weight solution of at least one copolyamide in a phenol / dichlorobenzene mixture at a weight ratio of 1:1.

[0076] When the viscosity number (VN) of at least one copolyamide (C)The viscosity number is preferably in the range of 160 to 290 ml / g, particularly preferably in the range of 170 to 280 ml / g, and is determined by a 0.5% weight solution of at least one copolyamide in a phenol / dichlorobenzene mixture at a weight ratio of 1:1.

[0077] Component A')

[0078] According to the present invention, component A') is at least one lactam.

[0079] In the context of this invention, "at least one lactam" is understood to mean precisely one lactam or a mixture of two or more lactams.

[0080] Lactams are known to those skilled in the art. According to the invention, lactams having 4 to 12 carbon atoms are preferred.

[0081] In the context of this invention, "lactam" should be understood to mean a cyclic amide having preferably 4 to 12 carbon atoms in the ring, particularly preferably 5 to 8 carbon atoms.

[0082] Suitable lactams are selected from, for example, 3-aminopropionic lactam (propion-3-lactam; β-lactam; β-propionolamide), 4-aminobutyrolactam (bution-4-lactam; γ-lactam; γ-butyrolactam), aminopentanolactam (2-piperidinone; δ-lactam; δ-pentanolactam), 6-aminocaprolactam (hexane-6-lactam; ε-lactam; ε-caprolactam), and 7-aminoheptanolactam (heptane-7-lactam; ζ-lactam; ζ-heptane). (lactam), 8-aminooctyllactam (oct-8-lactam; η-lactam; η-octyllactam), 9-aminononanolactam (non-9-lactam; θ-lactam; θ-nonanolactam), 10-aminodecanolactam (dec-10-lactam; ω-decanolactam), 11-aminoundecanolactam (undecane-11-lactam; ω-undecanolactam) and 12-aminododecanolactam (dodecane-12-lactam; ω-dodecanolactam).

[0083] Therefore, the present invention also provides a method wherein component A') is selected from 3-aminopropionic acid lactam, 4-aminobutyrolactam, 5-aminopentanolactam, 6-aminocaprolactam, 7-aminoheptanolactam, 8-aminooctanolactam, 9-aminononanolactam, 10-aminodecanolactam, 11-aminoundecaprolactam and 12-aminododecanolactam.

[0084] The lactam can be unsubstituted or at least monosubstituted. If a lactam with at least monosubstituted substituted molecule is used, its nitrogen atom and / or cyclic carbon atom can have one, two or more independently selected from C1 to C2. 10Alkyl, C5 to C6 cycloalkyl and C5 to C6 cycloalkyl 10 Substituents of aryl groups.

[0085] Suitable C1-to-C 10 The alkyl substituents are, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl. Suitable C5- to C6-cycloalkyl substituents are, for example, cyclohexyl. Preferred C5- to C6-cycloalkyl substituents... 10 -The aryl substituent is phenyl or anthracene.

[0086] Unsubstituted lactams are preferred, particularly γ-lactam (γ-butyrolactam), δ-lactam (δ-valerolactam), and ε-lactam (ε-caprolactam). δ-lactam (δ-valerolactam) and ε-lactam (ε-caprolactam) are especially preferred, with ε-caprolactam being particularly preferred.

[0087] Monomer mixture (M)

[0088] According to the present invention, component B') is a monomer mixture (M). The monomer mixture (M) includes component B1'), at least one C 32 -C 40 dimer acid, and B2'), at least one C4-C 12 diamine.

[0089] In the context of this invention, a monomer mixture (M) should be understood as a mixture of two or more monomers, wherein at least components B1' and B2' are present in the monomer mixture (M).

[0090] In the context of this invention, the terms "component B1'" and "at least one C" are used. 32 -C 40 "Dimer acid" is synonymous and therefore has the same meaning. The terms "component B2'" and "at least one C4-C" are interchangeable. 12 The same applies to "diamine". These terms are used synonymously in the context of this invention and therefore have the same meaning.

[0091] The monomer mixture (M) comprises, for example, in each case, 45 to 55 mol% of component B1' and 45 to 55 mol% of component B2' based on the sum of the molar percentages of components B1' and B2', preferably based on the total amount of matter in the monomer mixture (M).

[0092] When component B') includes component B1') in the range of 47 to 53 mol% and component B2') in the range of 47 to 53 mol%, in each case, it is preferred to be based on the sum of the molar percentages of components B1') and B2'), based on the total amount of substance of component B').

[0093] When component B') includes component B1') in the range of 49 to 51 mol% and component B2') in the range of 49 to 51 mol%, in each case, the total amount of substance of component B') is preferred, based on the sum of the molar percentages of components B1') and B2').

[0094] The sum of the molar percentages of components B1') and B2') present in component B') is typically 100 mol%.

[0095] Component B') may additionally include component B3'), at least one C4-C 20 Diacid.

[0096] In the context of this invention, the terms "component B3'" and "at least one C4-C" are used. 20 "Two acids" are synonyms and therefore have the same meaning.

[0097] When component B') further includes component B3'), based on the total amount of component B'), it is preferred that component B') includes component B1') in the range of 25 to 54.9 mol%, component B2') in the range of 45 to 55 mol%, and component B3') in the range of 0.1 to 25 mol%.

[0098] Particularly preferred is that, in each case, based on the total amount of component B'), component B') comprises component B1') ranging from 13 to 52.9 mol%, component B2') ranging from 47 to 53 mol%, and component B3') ranging from 0.1 to 13 mol%.

[0099] Most preferably, in each case, based on the total amount of component B'), component B') includes component B1') in the range of 7 to 50.9 mol%, component B2') in the range of 49 to 51 mol%, and component B3') in the range of 0.1 to 7 mol%.

[0100] When component B') also includes component B3'), the sum of the molar percentages of components B1'), B2') and B3') is typically 100 mol%.

[0101] The monomer mixture (M) may further include water.

[0102] Components B1') and B2') and optionally B3') of component B') can react with each other to obtain an amide. Such reactions are known to those skilled in the art. Therefore, component B') may include fully reacted, partially reacted, or unreacted forms of components B1'), B2') and optionally B3'). It is preferred when component B') includes unreacted forms of components B1'), B2') and optionally B3').

[0103] In the context of this invention, "unreacted form" should be understood as component B1') in at least one C 32 -C 40 It exists in the form of a dimer acid, and component B2') is in the form of at least one C4-C 12 It exists in the form of a diamine, and optionally, component B3') is in at least one C4-C form. 20 Exists in the form of diacids.

[0104] If components B1') and B2') and optional B3') react at least partially, then components B1') and B2') and any B3') are at least partially in amide form.

[0105] Component B1')

[0106] According to the present invention, component B1') is at least one C 32 -C 40 Dimer acid.

[0107] In the context of this invention, "at least one C" 32 -C 40 "Dimeric acid" should be understood as referring to a precise type of C 32 -C 40 Dimer acid or two or more C 32 -C 40 A mixture of dimer acids.

[0108] Dimer acids are also known as dimer fatty acids. C 32 -C 40 Dimer acids are known to those skilled in the art and are typically produced by the dimerization of unsaturated fatty acids. For example, such dimerization can be catalyzed by clay soil.

[0109] Used to produce at least one C 32 -C 40 Suitable unsaturated fatty acids for dimer acids are known to those skilled in the art, such as unsaturated C 16 - Fatty acids, unsaturated C 18 Fatty acids and unsaturated C 20 fatty acid.

[0110] Component B2')

[0111] According to the present invention, component B2') is at least one C4-C 12 diamine.

[0112] In the context of this invention, "at least one C4-C" 12 "Diamine" should be understood as referring to a precise C4-C... 12 Diamine or two or more C4-C12 A mixture of diamines.

[0113] In the context of this invention, "C4-C" 12 "Diamine" should be understood to refer to aliphatic and / or aromatic compounds having 4 to 12 carbon atoms and two amino groups (-NH2 groups). The aliphatic and / or aromatic compounds may be unsubstituted or, in addition, at least monosubstituted. If the aliphatic and / or aromatic compounds are, in addition, at least monosubstituted, they may have one, two, or more substituents that do not participate in the polymerization of components A') and B'). Such substituents are, for example, alkyl or cycloalkyl substituents. These are known to those skilled in the art. At least one C4-C 12 The diamine is preferably unsubstituted.

[0114] Suitable component B2' is selected from, for example, 1,4-diaminobutane (butane-1,4-diamine; tetramethylenediamine; putrescine), 1,5-diaminopentane (pentamethylenediamine; pentane-1,5-diamine; cadaverine), 1,6-diaminohexane (hexamethylenediamine; hexane-1,6-diamine), 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane (decamethylenediamine), 1,11-diaminoundecane (undecamethylenediamine), and 1,12-diaminododecane (dodecylmethylenediamine).

[0115] When component B2') is selected from tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, decamethylenediamine and dodecamethylenediamine, it is more preferred.

[0116] Component B3')

[0117] According to the present invention, component B3'), optionally present in component B'), is at least one C4-C. 20 Diacid.

[0118] In the context of this invention, "at least one C4-C" 20 "Diacid" should be understood as referring to a precise type of C4-C 20 Diosmin or two or more C4-C ions 20 A mixture of diacids.

[0119] In the context of this invention, "C4-C" 20"Diic acid" should be understood to refer to aliphatic and / or aromatic compounds having 2 to 18 carbon atoms and 2 carboxyl groups (-COOH groups). The aliphatic and / or aromatic compounds may be unsubstituted or, in addition, at least monosubstituted. If the aliphatic and / or aromatic compounds are, in addition, at least monosubstituted, they may have one, two, or more substituents that do not participate in the polymerization of components A') and B'). Such substituents are, for example, alkyl or cycloalkyl substituents. These are known to those skilled in the art. Preferably, at least one C4-C... 20 The diacid is unsubstituted.

[0120] Suitable components (B3') are selected from, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid and hexadecanoic acid.

[0121] When component B3') is selected from glutaric acid, adipic acid, sebacic acid and dodecanoic acid, it is more preferred.

[0122] When the components are PA 6 / 6.6 and / or PA 6 / 6.36, for example, having a melting point of 190 to 210°C, particularly 195 to 200°C, more specifically 196 to 199°C, and / or 60 to 80% by weight of (polymeric)caprolactam content, more preferably 65 to 75% by weight, particularly 67 to 70% by weight, with the remainder being hexamethylenediamine and C 36 The diacid-derived PA 6,36 unit is particularly preferred.

[0123] The solution according to the invention can be used to form mixtures of homopolyamides. Furthermore, monomers can be added to form copolyamides. For example, adipic acid / hexamethylenediamine salt (AH salt) or hexamethylenediamine / C salt can be added to the solution. 36 - Salt (6.36 salt). Based on the amount of lactam in the solution, when present, the amount of comonomer is preferably in the range of 40% to 5% by weight, more preferably 30% to 10% by weight.

[0124] Most preferably, ε-caprolactam is the only lactam in the solution and the only organic component in the solution other than cross-linked phenolic polymers or lignin and possible surfactants and / or colorants.

[0125] The solution is used as a solvent to dissolve the cross-linked phenolic polymer, more specifically, lignin. Therefore, the solution preferably further contains 0.1 to 40% by weight, more preferably 0.5 to 30% by weight, and most preferably 1 to 20% by weight of the cross-linked phenolic polymer, preferably lignin, based on the amount of (caprolactam) in the solution.

[0126] In solution, the lower limit of lignin content can be 0.1% by weight, preferably 0.5% by weight, more preferably 1% by weight, even more preferably 1.5% by weight, particularly 2% by weight, and even more particularly 5% by weight. Each of these lower limits can be combined with an upper limit selected from 40% by weight, preferably 30% by weight, more preferably 20% by weight to form a preferred range.

[0127] Particularly preferred is that the amount of lignin exceeds 1% by weight, preferably at least 1.5% by weight, more preferably at least 2% by weight, and most preferably at least 5% by weight.

[0128] Lignin can be dissolved using known means and methods. Generally, stirring the solution helps to promote dissolution.

[0129] Cross-linked phenolic polymers, preferably lignin-based (caprolactam) aqueous solutions, can be used to produce homogeneous polyamide / lignin mixtures, preferably polyamide 6 / lignin mixtures.

[0130] The term "uniform" refers to the preferred mixing of the polyamide chains and the cross-linked phenolic polymer at the molecular level. Preferably, the size of the lignin domain within the polyamide matrix does not exceed 50 micrometers, more preferably not more than 25 micrometers, and most preferably not more than 10 micrometers. Typically, the lignin domain is not visible under a conventional light microscope with a magnifying glass of 240 to 360x.

[0131] According to the present invention, a homogeneous polyamide / lignin mixture is obtained by polymerizing lactam in a solution containing lactam, water, and dissolved lignin. Therefore, the mixing of polyamide and lignin can be achieved at the molecular level.

[0132] Preferably, the homogeneous polyamide / lignin mixture is produced by a method involving the ring-opening polymerization of an aqueous lactam in an aqueous solution, wherein water is removed (e.g., throughout the polymerization process), the aqueous solution initially containing water and 50 to 95% by weight of lactam based on the total weight of water and lactam in the solution, and further containing 0.1 to 40% by weight of a crosslinked phenolic polymer, preferably lignin, based on the amount of lactam in the solution.

[0133] Similarly, the lactam is preferably ε-caprolactam, and the polyamide is preferably polyamide 6.

[0134] The resulting polyamide / lignin mixture typically has a lignin content of 0.1 to 40% by weight, more preferably 0.5 to 30% by weight, and most preferably 1 to 20% by weight. Specifically, it is preferred that the lower limit of the lignin content is 1.5% by weight, more preferably 2% by weight, and most preferably 5% by weight, while the upper limit is 40% by weight, preferably 30% by weight, and more preferably 20% by weight.

[0135] Polyamide / lignin blends can be used to form thermoplastic molding compositions by adding further components.

[0136] The present invention also relates to a thermoplastic molding composition comprising:

[0137] a) 40 to 100 wt% homogeneous polyamide / lignin mixture as component A, wherein the mixture contains 0.1 to 40 wt% lignin based on the amount of polyamide, the polyamide comprising polymerized lactam units.

[0138] b) 0 to 10% by weight of polyamide without polymeric lactam units as component B.

[0139] c) 0 to 45% by weight of at least one elastic polymer as component C,

[0140] d) 0 to 60% by weight of at least one fibrous and / or particulate filler as component D,

[0141] e) 0 to 25% by weight of further additives as component E,

[0142] The total weight percentage of components A to E is 100% by weight.

[0143] In this composition, component A is preferably produced by a method involving the ring-opening polymerization of an aqueous lactam in an aqueous solution, wherein water is removed, the aqueous solution initially comprising water and 50 to 95% by weight of lactam based on the total weight of water and lactam in the solution, and further comprising 0.1 to 40% by weight of a crosslinked phenolic polymer, preferably lignin, based on the amount of lactam in the solution.

[0144] Further components will be described below. As component B, the thermoplastic molding composition may contain 0 to 10% by weight, more preferably 0 to 5% by weight, and most preferably 0 to 2.5% by weight of a polyamide without polymeric lactam units. Therefore, polyamide component B is structurally different from the polyamide contained in component A, and possible polyamides of component B will be described below.

[0145] The polyamide of component B may have an intrinsic viscosity of 90 to 350 mL / g, preferably 110 to 240 mL / g, as determined according to ISO 307 in a 0.5% strength solution of 96% by weight sulfuric acid at 25°C, unless otherwise specified.

[0146] Semi-crystalline or amorphous resins with a molecular weight (weight average) of at least 5,000 are preferred, such as those described in the following U.S. patents: 2,071,250, 2,071,251, 2,130,523, 2,130,948, 2,241,322, 2,312,966, 2,512,606, and 3,393,210.

[0147] The dicarboxylic acids that can be used are alkane dicarboxylic acids having 6 to 12 carbon atoms, particularly 6 to 10 carbon atoms, as well as aromatic dicarboxylic acids. Just as examples, adipic acid, azelaic acid, sebacic acid, dodecanoic acid, and terephthalic acid and / or isophthalic acid may be mentioned here.

[0148] Particularly suitable diamines are alkyl diamines having 6 to 12 carbon atoms, especially 6 to 8 carbon atoms, as well as m-phenylenediamine, bis(4-aminophenyl)methane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminocyclohexyl)propane, and 1,5-diamino-2-methylpentane.

[0149] Preferred polyamides are polyhexamethylene adipamide, polyhexamethylene sebacate diamide for B, and nylon-6 / 6,6 copolyamides, particularly those having a proportion of 5-95% by weight of caprolactam units (e.g., BASF SE). C31), used for component A.

[0150] Polyamides can also be mentioned, for example, polyamides (nylon 4,6) obtained by the condensation of 1,4-diaminobutane with adipic acid at high temperature. Methods for preparing polyamides of this structure are described by way of example in EP-A 38 094, EP-A 38 582 and EP-A39 524.

[0151] Other suitable examples are polyamides that can be obtained by copolymerizing two or more of the above monomers, and mixtures of two or more polyamides in any desired mixing ratio. Mixtures of nylon 6,6 with other polyamides are particularly preferred, especially mixtures of nylon 6 (component A) and nylon 66 (as component B), as well as nylon 6 / 6,6 copolyamides and nylon 6,6 / 6 copolyamides (in component A).

[0152] Other copolyamides that have proven particularly advantageous are semi-aromatic copolyamides in component A, such as PA 6 / 6T and PA66 / 6T, wherein the triamine content is less than 0.5% by weight, preferably less than 0.3% by weight (see EP-A 299 444). Other heat-resistant polyamides are known in EP-A 19 94 075 (PA 6T / 6I / MXD6).

[0153] The methods described in EP-A 129 195 and 129 196 can be used to prepare preferred semi-aromatic copolyamides with low triamine content.

[0154] The following list is not exhaustive; it includes the polyamide of component A above (if the lactam is part of the monomer) and other polyamides B used in this invention, as well as the monomers contained in the polyamide:

[0155] AA / BB polymer:

[0156] PA 46 Tetramethylenediamine, Adipic acid

[0157] PA 66 Hexamethylenediamine, adipic acid

[0158] PA 69 Hexamethylenediamine, Azelaic Acid

[0159] PA 610 Hexamethylenediamine, Sebacic Acid

[0160] PA 612 Hexamethylenediamine, Decanedicarboxylic Acid

[0161] PA 613 Hexamethylenediamine, Undecanedicarboxylic Acid

[0162] PA 1212 1,12-Dodecanediamine, Decanedicarboxylic Acid

[0163] PA 1313 1,13-Diaminotridecane,undecanedicarboxylic acid

[0164] PA 6T hexamethylenediamine, terephthalic acid

[0165] PA MXD6 m-phenylenediamine, adipic acid

[0166] AA / BB polymer (if the lactam is copolymerized, it belongs to component A):

[0167] PA 6I Hexamethylenediamine, Isophthalic Acid

[0168] PA 6-3-T Trimethylhexamethylenediamine, terephthalic acid

[0169] PA 6 / 6.36 (see below)

[0170] PA 6 / 6T (see PA 6 and PA 6T)

[0171] PA 6 / 66 (see PA 6 and PA 66)

[0172] PA 6 / 12 (see PA 6 and PA 12)

[0173] PA 66 / 6 / 610 (see PA 66, PA 6 and PA 610)

[0174] PA 6I / 6T (see PA 6I and PA 6T)

[0175] PA PACM 12 Diaminodicyclohexylmethane, laurolactam

[0176] PA 6I / 6T / PACM as PA 6I / 6T + diaminodicyclohexylmethane

[0177] PA 12 / MACMI laurolactam, dimethyldiaminodicyclohexylmethane, isophthalic acid

[0178] PA 12 / MACMT laurolactam, dimethyldiaminodicyclohexylmethane, terephthalic acid

[0179] PA PDA-T phenylenediamine, terephthalic acid

[0180] Preferred polyamides are PA 6, PA 66, PA 6 / 66, PA 66 / 6, PA 12, PA 6.10, PA 6T / 6, PA 6I / 6T, PA 6T / 6I, PA 9T, PA 4T, and copolyamides polymerized from the following components.

[0181] A') 15 to 84% by weight of at least one lactam,

[0182] B') 16 to 85% by weight of a monomer mixture (M), comprising the following components

[0183] B1') at least one C 32 -C 40 dimer acids, and

[0184] B2') at least one C4-C 12 diamine,

[0185] The weight percentages of components A') and B') in each case are based on the sum of the weight percentages of components A') and B') in each case.

[0186] In particular, PA 6 / 6.6 and / or PA 6 / 6.36.

[0187] The most preferred polyamides are PA 6, PA 66, PA 6 / 66, PA 66 / 6, and PA 6 / 6.36.

[0188] DE-A-10 2009 011 668 provides a more specific description of suitable copolyamides.

[0189] As component C, the molding composition of the present invention may include 0 to 45% by weight, preferably 0 to 40% by weight, at least one elastic polymer.

[0190] If an elastic polymer is present, its minimum amount is preferably 1% by weight, more preferably 2% by weight, and most preferably 5% by weight. Therefore, if the elastic polymer of component C is present in the molding composition, its amount is preferably 1 to 45% by weight, more preferably 2 to 40% by weight, and most preferably 5 to 40% by weight. In this case, the maximum amount of component A is reduced by the minimum amount of component C.

[0191] Component C may be selected from all elastic polymers, impact modifiers, elastomers or rubbers suitable for polyamide molding compositions.

[0192] Preferably, component C is selected from...

[0193] b1) Ethylene and at least one compound selected from C 3-12 Olefins, (meth)acrylic acid C 1-12 A copolymer of alkyl esters, (meth)acrylic acid, and maleic anhydride, as component B1.

[0194] b2) Polyethylene or polypropylene, as component B2),

[0195] Components B1) and B2) may also be additionally grafted with maleic anhydride, preferably from ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butyl acrylate copolymer, copolymers of ethylene and / or propylene with maleic anhydride, and mixtures thereof.

[0196] These elastic polymers (also often referred to as impact modifiers, elastomers, or rubbers) are typically copolymers composed of at least two of the following monomers: acetylene, propylene, butadiene, isobutylene, isoprene, chloroprene, vinyl acetate, styrene, acrylonitrile, and acrylates and / or methacrylates having 1 to 18 carbon atoms in the alcohol component.

[0197] For example, Houben-Weyl, Method of Organischen Chemie, vol. 14 / 1 (Georg-Thieme-Verlag, Stuttgart, Germany, 1961), pp. 392–406, and C.B. Bucknall’s The Monograph, Toughened Plastics (Applied Science Publishers, London, UK, 1977) describe this type of polymer.

[0198] As component D, the thermoplastic molding composition contains 0 to 60% by weight, preferably 0 to 50% by weight, more preferably 0 to 40% by weight, at least one fibrous and / or particulate filler.

[0199] Preferably, component D comprises glass fiber, the content of which is 10 to 60% by weight, more preferably 15 to 50% by weight, and most preferably 20 to 40% by weight.

[0200] If component D is present, the maximum amount of component A must be reduced by the minimum amount of component D, so the total amount of components A through E remains 100 by weight.

[0201] The fibrous or granular fillers D that can be mentioned are carbon fiber, glass fiber, glass beads, amorphous silica, calcium silicate, calcium metasilicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica, barium sulfate, and feldspar.

[0202] Preferred fibrous fillers include carbon fibers, aramid fibers, and potassium titanate fibers, with glass fibers in the form of E-glass being particularly preferred. These fibers can be used as rovings or as commercially available crushed glass.

[0203] Fiber-like fillers can be surface-pretreated with silane compounds to improve their compatibility with thermoplastic materials.

[0204] Suitable silane compounds have the general formula:

[0205] (X–(CH2) n ) k –Si–(O–C m H 2m+1 ) 4–k

[0206] The substituents are defined as follows:

[0207]

[0208] n is an integer from 2 to 10, preferably 3 to 4.

[0209] m is an integer from 1 to 5, preferably 1 to 2, and

[0210] k is an integer from 1 to 3, preferably 1.

[0211] Preferred silane compounds are aminopropyltrimethoxysilane, aminobutyltrimethoxysilane, aminopropyltriethoxysilane, and aminobutyltriethoxysilane, as well as corresponding silanes containing a glycidyl group as substituent X.

[0212] The amount of silane compound typically used for surface coatings is 0.01 to 2% by weight, preferably 0.025 to 1.0% by weight, and particularly 0.05 to 0.5% by weight (based on component D).

[0213] Needle-shaped mineral fillers are also suitable.

[0214] In this invention, needle-like mineral fillers refer to mineral fillers with strongly developed needle-like characteristics. An example is needle-like wollastonite. The mineral preferably has an L / D (length / diameter) ratio of 8:1 to 35:1, more preferably 8:1 to 11:1. The mineral filler may optionally be pretreated with the aforementioned silane compounds, but pretreatment is not mandatory.

[0215] Other fillers that may be mentioned include kaolin, calcined kaolin, wollastonite, talc, and chalk, as well as sheet-like or needle-like nanofillers, the amount of which is preferably 0.1% to 10%. For this purpose, preferred materials are boehmite, bentonite, montmorillonite, vermiculite, lithium montmorillonite, and soapstone. The sheet-like nanofillers are organically modified using existing methods to ensure good compatibility with organic binders. The addition of sheet-like or needle-like nanofillers to the nanocomposite materials of this invention can further improve mechanical strength.

[0216] As component E, the molding composition of the present invention may contain 0 to 25% by weight, preferably 0 to 20% by weight, more preferably 0 to 15% by weight of further additives.

[0217] If further additives are used, the minimum amount is preferably 0.1% by weight, more preferably 0.25% by weight, and most preferably 0.5% by weight.

[0218] The thermoplastic molding composition of the present invention may include conventional processing aids as component E, further stabilizers, oxidation retarders, agents that resist thermal decomposition and UV decomposition, lubricants and release agents, colorants such as dyes and pigments, nucleating agents, plasticizers, etc.

[0219] The molding composition of the present invention may include 0.05 to 3% by weight, preferably 0.1 to 1.5% by weight, and particularly 0.1 to 1% by weight of a lubricant as component E1.

[0220] Salts of Al, alkali metals or alkaline earth metals are preferred, or esters or amides of fatty acids having 10 to 44 carbon atoms, preferably having 12 to 44 carbon atoms.

[0221] The preferred metal ions are alkaline earth metals and Al, with Ca or Mg being particularly preferred.

[0222] Preferred metal salts are calcium stearate and calcium lignite, as well as aluminum stearate.

[0223] A mixture of various salts can also be used, in any desired mixing ratio.

[0224] Carboxylic acids can be mono- or di-carboxylic. Examples that can be mentioned include nonanoic acid, palmitic acid, lauric acid, heptadecanic acid, dodecanoic acid, benzyl acid, especially stearic acid, decanoic acid, and linalic acid (a mixture of fatty acids with 30 to 40 carbon atoms).

[0225] Aliphatic alcohols can be mono- or tetra-membered. Examples of alcohols include n-butanol, n-octanol, stearyl alcohol, ethylene glycol, propylene glycol, neopentyl glycol, and pentaerythritol, with glycerol and pentaerythritol being preferred.

[0226] Aliphatic amines can be mono- or ternary aliphatic amines. Examples of these are stearylamine, ethylenediamine, propylenediamine, hexamethylenediamine, and di(6-aminohexyl)amine, with ethylenediamine and hexamethylenediamine being particularly preferred. Preferred esters or amides are the corresponding distearate, tristearate, ethylenediamine distearate, monopalmitate, trilaurate, monostilbene, and pentaerythritol tetrastearate.

[0227] Mixtures of various esters or amides, or mixtures of esters and amides, can also be used in any desired mixing ratio.

[0228] As component E, the molding material according to the invention may include at least one heat stabilizer, preferably 0.01 to 3% by weight, particularly preferably 0.02 to 2% by weight, and especially 0.05 to 1.0% by weight, based on the total weight of the composition.

[0229] The heat stabilizer is preferably selected from copper compounds, secondary aromatic amines, stereohedral phenols, phosphites, phosphonites and mixtures thereof.

[0230] As component E, at least one stereohedral hindered (phenolic) antioxidant may be used in amounts of 0.05 to 3% by weight, preferably 0.1 to 2% by weight, and particularly 0.1 to 1% by weight.

[0231] Component E preferably has a molecular weight of more than 500 g / mol, more preferably more than 1000 g / mol. Furthermore, component C preferably exhibits high thermal stability, for example, in a TGA (thermogravimetric analysis) experiment at 300°C under nitrogen (40°C to 120°C, 10°C / min, followed by a 15-minute isothermal period, then 120°C to 600°C, 20°C / min), with a maximum weight loss of 5%, more preferably 2%.

[0232] Component E preferably has at least one, more preferably at least two, branches of at least one C. 3-12 -Alkyl groups are substituted for phenolic groups as steric hindrance groups. The substituted phenolic groups are covalently linked to the structure of component E.

[0233] A suitable stereohedral phenol E is, in principle, any compound having a phenolic structure and at least one large group on the phenolic ring. A large group is, for example, a branched C. 3-12 Alkyl groups, preferably branched C4 groups 3-6 Alkyl groups, more preferably isopropyl or tert-butyl groups.

[0234] Examples of the above-mentioned types of antioxidants are provided in DE-A 27 02 661 (US-A 4 360 617).

[0235] Another preferred group of stereohedral phenols are those derived from substituted phenyl carboxylic acids, particularly substituted phenyl propionic acids, which preferably have at least one large group on the phenyl group. Their structure contains at least one, preferably two, covalently linked substituted phenyl carboxylic acid units, which preferably have at least one large group on the phenyl group.

[0236] Preferred phenylcarboxylic acid is phenyl C 1-12 Carboxylic acid, more preferably phenyl C 2-6 Carboxylic acid. As described above, the phenyl group is preferably a phenolic group having at least one large group on the phenolic ring. Therefore, the above-mentioned stereohedged phenol is preferably with C 1-12 Alkyl carboxylic acids, more preferably linear C 2-6 Alkyl carboxylic acid is covalently linked.

[0237] It should be mentioned that all of the following substances are examples of stereohedged phenols:

[0238] 2,2'-Methylenebis(4-methyl-6-tert-butylphenol), 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (BASF SE) 1010), 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid distearate, 2,6,7-trioxo-1-phosphorylbicyclo[2.2.2]oct-4-ylmethyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 3,5-di-tert-butyl-4-hydroxyphenyl-3,5-distearatethiotriazoleamine, 2-(2'-hydroxy-3'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzyltriazole, 2,6-di-tert-butyl-4-hydroxymethylphenol, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 4,4'-methylenebis(2,6-di-tert-butylphenol), 3,5-di-tert-butyl-4-hydroxybenzyldimethylamine.

[0239] The compounds that have proven particularly effective and are therefore preferred are 2,2'-methylenebis(4-methyl-6-tert-butylphenol) and 1,6-hexanediol bis(3,5-di-tert-butyl-4-hydroxyphenyl) propionate. 259), pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and N,N'-hexamethylenebis-3,5-di-tert-butyl-4-hydroxyhydrocinnamate ( 1098), and the aforementioned BASF SE 245 and 1010 products have particularly good applicability.

[0240] The molding composition of the present invention may include 0.05-3% by weight, preferably 0.1-1.5% by weight, particularly 0.1-1% by weight, of a copper stabilizer, preferably a Cu(I) halide, particularly with an alkali metal halide, preferably KI, particularly in a 1:4 ratio, or stereohindered phenol, or a mixture thereof, as component E2.

[0241] Preferred monovalent copper salts are cuprous acetate, cuprous chloride, cuprous bromide, and cuprous iodide. Based on polyamides, these materials contain 5 to 500 ppm of copper, preferably 10 to 250 ppm.

[0242] Advantageous properties are particularly desirable when copper is present in the polyamide in a molecularly distributed manner. This can be achieved by adding a concentrate in the form of a solid homogeneous solution containing polyamide, a monovalent copper salt, or an alkali metal halide to the molding composition. For example, a typical concentrate consists of 79-95 wt% polyamide and 21-5 wt% a mixture of copper iodide or copper bromide and potassium iodide. Based on the total weight of the solution, the copper concentration in the solid homogeneous solution is preferably 0.3 to 3 wt%, particularly 0.5 to 2 wt%, and the molar ratio of cuprous iodide to potassium iodide is 1 to 11.5, preferably 1 to 5.

[0243] The polyamides suitable for this concentrate are homopolymers and copolymers, especially nylon 6.

[0244] According to a preferred embodiment of the invention, the molding composition is free of copper, especially free of copper stabilizers such as Cu / (I) halides, and combinations of Cu(I) halides and alkali metal halides.

[0245] More preferably, the thermoplastic molding composition of the present invention is free of metal halides. Systems free of metal halides, i.e., so-called electrically friendly systems, are of great interest because electrification, connectivity, and mobility are growing trends in almost all industries.

[0246] Therefore, thermoplastic molding compositions are preferably free of metal halides, especially copper halides and alkali metal halides.

[0247] The UV stabilizers that can be mentioned, generally used at most 2% by weight, are various substituted resorcinols, salicylates, benzotriazoles, and benzophenones, based on the molding composition. Nigroscin can also be used.

[0248] Materials that can be added as colorants include inorganic pigments such as titanium dioxide, ultramarine, iron oxide, and carbon black, as well as organic pigments such as phthalocyanine, quinacrine, and perylene, and dyes such as anthraquinone.

[0249] Materials that can be used as nucleating agents include sodium phenylphosphinate, alumina, and silicon dioxide, with talc being a preferred choice.

[0250] The thermoplastic molding composition may further include a flame retardant as component E, such as phosphazene, at least one metal phosphonate or phosphonate, halogenated flame retardant, melamine compound, triazine, guanidine compound, allantoin compound, cyanoguanidine, metal oxide, such as antimony trioxide, antimony pentoxide, sodium antimonate and similar metal oxides, and phosphorus, such as red phosphorus.

[0251] As component E, the thermoplastic molding material may include 1.0 to 10.0% by weight, preferably 2.0 to 6.0% by weight, and particularly 3.0 to 5.0% by weight of at least one of the flame retardants described above.

[0252] The minimum content of component E is at least 1.0 wt%, preferably 2.0 wt%, and particularly 3.0 wt%.

[0253] The maximum amount of component E is 10.0 wt%, preferably 6.0 wt%, and particularly preferably 5.0 wt%.

[0254] These materials are suitable for producing any type of fiber, foil, and molded product. Some examples include: extruded tubing, such as for automotive applications (e.g., brake fluid hoses), cable lead systems or cable management systems (cable ties, corrugated tubing), shoe soles, the base material (mandrel) for producing rubber tubing, and sports equipment such as ski boots or soccer shoes.

[0255] The following items define embodiments of the present invention.

[0256] 1. Use of an aqueous lactam solution as a solvent, said aqueous lactam solution having a lactam content of 50 to 95% by weight, based on the total weight of water and lactam in the solution.

[0257] 2. As defined in paragraph 1, as a solvent for organic compounds, preferably for cross-linked phenolic polymers, and more preferably for lignin.

[0258] 3. As defined in item 1 or 2, wherein the lactam is ε-caprolactam.

[0259] 4. An aqueous solution of lactam, wherein the aqueous solution of lactam has a lactam content of 50 to 95% by weight, based on the total weight of water and lactam in the solution.

[0260] 5. A solution as defined in item 4, wherein the lactam is ε-caprolactam.

[0261] 6. The solution as defined in item 5 has a caprolactam content of 75 to 95% by weight, preferably 78 to 87% by weight, based on the total weight of water and caprolactam in the solution.

[0262] 7. The solution as defined in any one of 3 to 6 further comprises 0.1 to 40% by weight of a crosslinked phenolic polymer, preferably lignin, based on the amount of lactam in the solution.

[0263] 8. A solution as defined in paragraph 7, comprising 0.5 to 30% by weight, preferably 1 to 20% by weight, of lignin, based on the amount of lactam in the solution.

[0264] 9. Use of an aqueous lactam solution for producing a homogeneous polyamide / lignin mixture, the aqueous lactam solution having a lactam content of 50 to 95% by weight based on the total weight of the solution, and further comprising 0.1 to 40% by weight of a crosslinked phenolic polymer, preferably lignin, based on the amount of lactam in the solution.

[0265] 10. As defined in item 9, wherein the lactam is ε-caprolactam and the polyamide is polyamide 6.

[0266] 11. A method for producing a homogeneous polyamide / lignin mixture, comprising the step of ring-opening polymerization of an aqueous lactam in an aqueous solution, wherein water is removed, the aqueous solution initially comprising water and 50 to 95% by weight of lactam based on the total weight of water and lactam in the solution, and further comprising 0.1 to 40% by weight of a crosslinked phenolic polymer, preferably lignin, based on the amount of lactam in the solution.

[0267] 12. The method as defined in item 11, wherein the lactam is ε-caprolactam and the polyamide is polyamide 6.

[0268] 13. A thermoplastic molding composition comprising

[0269] a) A homogeneous polyamide / lignin mixture of 40 to 100 wt% as component A, wherein the mixture contains 0.1 to 40 wt% lignin based on the amount of polyamide, wherein the polyamide comprises polymerized lactam units.

[0270] b) 0 to 10% by weight of polyamide without polymeric lactam units, as component B.

[0271] c) 0 to 45% by weight of at least one elastic polymer, as component C,

[0272] d) 0 to 60% by weight of at least one fibrous and / or particulate filler, as component D,

[0273] e) 0 to 25% by weight of further additives, as component E,

[0274] The total weight percentage of components A to E is 100% by weight.

[0275] 14. The thermoplastic molding composition as defined in item 13, wherein component A is obtained by a method involving the ring-opening polymerization of an aqueous lactam in an aqueous solution, wherein water is removed, the aqueous solution initially comprising water and 50 to 95% by weight of lactam based on the total weight of water and lactam in the solution, and further comprising 0.1 to 40% by weight of crosslinked phenolic polymer, preferably lignin, based on the amount of lactam in the solution.

[0276] 15. A thermoplastic molding composition as defined in item 13 or 14, wherein the polyamide in component A is polyamide 6, and component A is preferably obtained by a method involving the ring-opening polymerization of an aqueous lactam in an aqueous solution, wherein water is removed, the aqueous solution initially containing 50 to 95% by weight of ε-caprolactam based on the total weight of water and lactam in the solution and further containing 0.1 to 40% by weight of lignin based on the amount of ε-caprolactam in the solution.

[0277] 16. Use of the thermoplastic molding composition as defined in any one of items 13 to 15 for forming molded articles, fibers or foils.

[0278] 17. A molded article, fiber, or foil made from a thermoplastic molding composition as defined in any one of items 13 to 15.

[0279] The present invention is further illustrated by the following embodiments. Example

[0280] Various polyamides were synthesized in batches using a stirred autoclave. Aqueous monomer / lignin mixtures were heated to 240°C under pressure. After maintaining a pressure of approximately 9 to 16 bar for 30 minutes, the external temperature was increased to 260°C, and the pressure was slowly released while water was condensed from the system. The polymer melt was stirred at atmospheric pressure and 260°C until a specific melt viscosity (torque ~55 to 60 Nm) was reached. At the bottom of the vessel, a stream of melt was released under nitrogen pressure. This stream was cooled in a water bath and subsequently granulated. The remaining caprolactam monomer / oligomer was then extracted in hot water for 16 hours, and the remaining material was dried under vacuum (80°C / 50 mbar).

[0281] Example 1

[0282] Kraft lignin from Finnish cork was used in the following experiments. The lignin was dissolved in a solvent system consisting of 80 wt% ε-caprolactam and 20 wt% water.

[0283] The dosage of caprolactam-based lignin is shown in Table 1 below.

[0284] Table 1: PA 6 lignin complex.

[0285]

[0286] The relative viscosity RV was determined by viscosity measurement according to DIN ISO 307 (valid 2020 version). 96% H2SO4 was used as the solvent.

[0287] The amine-terminated group content (AEG) was determined using the following procedure: 1 gram of polyamide was dissolved in 30 mL of a phenol / methanol mixture (75:25 m / m). The solution was titrated with an aqueous solution of 0.02 N hydrochloric acid.

[0288] The content of extractable material was determined by methanol extraction according to DIN ISO 6427 (2020 version): polyamide particles were extracted in boiling methanol for 16 hours. The extractable material dissolved in methanol was determined by gravimetric method.

[0289] As shown in Table 1, up to 20% by weight of lignin dissolved in CPL aqueous solution was copolymerized into PA 6 lignin complexes. These complexes were homogeneous; for example, the color of the entire complex particle was uniform, and no phase separation of lignin particles was observed. The obtained relative viscosity (RV) was within the range typical for PA materials (e.g., 1.5 to 2.7), demonstrating that lignin did not interfere with the polymerization of caprolactam (CPL). Analytical data showed no effect on residual primary amine end groups (AEG) and extractables (e.g., unreacted CPL and its oligomers).

[0290] The thermal properties of the PA 6 lignin complex were only slightly affected by the addition of up to 10% wt% lignin. Table 2 shows the key thermal parameters obtained from DSC (Differential Scanning Calorimetry) measurements. DSC measurements were performed over a temperature range of 0 to 280 °C at a heating / cooling rate of 20 K / min. g 2. T m The value of 2 is taken from the second heating run, T K and T KB The value is taken from the second cooling run.

[0291] Table 2: Thermal properties of PA 6 lignin complex.

[0292]

[0293] As shown in Table 2, with the increase of lignin content, the onset and peak temperatures of crystallization (T) increase. KB and T K Only slight changes were observed in the glass transition and melting temperature (T).g T m There has been virtually no change.

[0294] Example 2

[0295] To further broaden the concept, different lignin sources were tested. Kraft lignin from the Northern Hemisphere (Canada) and the Southern Hemisphere (Brazil) was applied to caprolactam solutions of 2 wt% and 5 wt%. All obtained PA 6 lignin complexes were homogeneous. The thermal properties of these complexes showed negligible variation in key figures. The datasets are shown in Table 3.

[0296] Table 3: Thermal properties of PA 6 lignin complex.

[0297]

[0298] *A mixture of 90% hybrid eucalyptus Urograndis and 10% eucalyptus Urophylla and eucalyptus Grandis grown in Brazil.

[0299] Example 3

[0300] To demonstrate the multifunctionality of this system, a polyamide copolymer containing Kraft lignin (Finland) was synthesized. For this purpose, an aqueous caprolactam solution containing 1 to 5% by weight of lignin was mixed with a certain amount of comonomer (such as adipic acid / hexamethylenediamine salt = AH salt or hexamethylenediamine / C...). 36 - Salt (6.36 salts) were mixed. Copolymerization was carried out using standard reaction conditions. The results are shown in Table 4.

[0301] Table 4: Lignin polyamide copolymers.

[0302]

[0303] All obtained PA lignin complexes were homogeneous. Their properties were similar to those of the non-lignin complexes. The datasets are shown in Table 5.

[0304] Table 5: Data on lignin-polyamide copolymers.

[0305]

[0306] Example 4

[0307] PA 6 lignin complex was prepared according to Example 1 of the present invention, and the results were compared by mixing lignin powder in PA 6 with the aid of an extruder.

[0308] Samples No. 3 and 4 were prepared according to Example 1 of the present invention and contained 2% by weight and 5% by weight of lignin dissolved in a solvent system, respectively.

[0309] For the PA 6 lignin composite according to the invention, samples No. 3 and 4 of Example 1 were used to prepare foils with a thickness of 100 micrometers and injection-molded sheets with dimensions of 30 × 30 × 1 mm. They were prepared by melting particles of the PA 6 lignin composite at 260°C and injection molding at a mold temperature of 80°C. After cooling to room temperature, the sheets were removed from the mold. Comparative samples No. c1, c2, and c3 contained 1 wt%, 2 wt%, and 5 wt% of the lignin used in Example 1, added in powder form to PA 6, respectively.

[0310] In the comparative tests, 1 wt%, 2 wt%, or 5 wt% lignin was added to PA 6 of Example 1 in an extruder. Kraft lignin from Finnish cork, as used in Example 1, was employed.

[0311] Similarly, aluminum foil and injection-molded sheets were prepared.

[0312] Visual inspection of the foils revealed that the foils prepared according to the present invention, based on samples No. 3 and 4, showed no black spots but had a uniform appearance. The foils prepared according to the comparative test showed small black spots as defects (bad spots), indicating inhomogeneity of the mixture due to the lignin phase.

[0313] The transparency of the molded panels was measured using a BYK Gardner haze-gard plus. Total light transmittance was determined according to ASTM D 1003.

[0314] The results are shown in Table 6.

[0315] Table 6: Transparency Measurement of PA 6 Lignin Complex

[0316] Sample No. Total transmittance (%) c1 24.3 c2 17.1 c3 6.8 3 0.6 4 0.0

[0317] The lower light transmittance indicates that the lignin is more evenly distributed in the polyamide matrix.

[0318] Due to the uniform distribution of lignin in PA 6, the total light transmittance of the board prepared according to the present invention is very low. In contrast, the comparative sample exhibits higher total light transmittance due to the larger domain of lignin within the polyamide matrix. The results indicate that, compared to the comparative sample, the PA 6 lignin composite prepared according to the present invention results in better lignin distribution within the polyamide.

[0319] The composite according to the invention is more uniform than the comparative composite.

Claims

1. Use of an aqueous lactam solution as a solvent for a crosslinked phenolic polymer, the aqueous lactam solution having a lactam content of 50 to 95% by weight, based on the total weight of water and lactam in the solution, wherein the lactam is ε-caprolactam, and wherein the crosslinked phenolic polymer is lignin.

2. An aqueous lactam solution having a lactam content of 50 to 95% by weight based on the total weight of water and lactam in the solution and further comprising 0.1 to 40% by weight of a crosslinked phenolic polymer based on the amount of lactam in the solution, wherein the lactam is ε-caprolactam and wherein the crosslinked phenolic polymer is lignin.

3. The solution according to claim 2, having a caprolactam content of 75 to 95% by weight, based on the total weight of water and caprolactam in the solution.

4. The solution according to claim 2, having a caprolactam content of 78 to 87% by weight, based on the total weight of water and caprolactam in the solution.

5. The solution according to claim 2, comprising 0.5 to 30% by weight of lignin, based on the amount of lactam in the solution.

6. The solution according to claim 2, comprising 1 to 20% by weight of lignin, based on the amount of lactam in the solution.

7. The solution according to claim 3, comprising 0.5 to 30% by weight of lignin, based on the amount of lactam in the solution.

8. The solution according to claim 3, comprising 1 to 20% by weight of lignin, based on the amount of lactam in the solution.

9. Use of an aqueous lactam solution for producing a homogeneous polyamide / lignin mixture, the aqueous lactam solution having a lactam content of 50 to 95% by weight based on the total weight of the solution and further comprising 0.1 to 40% by weight of a crosslinked phenolic polymer based on the amount of lactam in the solution, wherein the lactam is ε-caprolactam and wherein the crosslinked phenolic polymer is lignin.

10. The use according to claim 9, wherein the polyamide is polyamide 6.

11. A method for producing a homogeneous polyamide / lignin mixture, comprising the step of ring-opening polymerization of an aqueous lactam in an aqueous solution, wherein water is removed, the aqueous solution initially comprising water and 50 to 95 wt% lactam based on the total weight of water and lactam in the solution and further comprising 0.1 to 40 wt% crosslinked phenolic polymer based on the amount of lactam in the solution, wherein the lactam is ε-caprolactam and wherein the crosslinked phenolic polymer is lignin.

12. The method of claim 11, wherein the polyamide is polyamide 6.

13. A thermoplastic molding composition comprising a) A homogeneous polyamide / lignin mixture of 40 to 100 wt% as component A, comprising 0.1 to 40 wt% lignin based on the amount of polyamide, wherein the polyamide comprises polymerized lactam units. b) 0 to 10% by weight of polyamide without polymeric lactam units as component B. c) 0 to 45% by weight of at least one elastic polymer as component C, d) 0 to 60% by weight of at least one fibrous and / or particulate filler as component D, e) 0 to 25% by weight of further additives as component E, The total weight percentage of components A to E is 100% by weight, wherein component A is obtained by a method involving the ring-opening polymerization of an aqueous lactam in an aqueous solution, wherein water is removed, the aqueous solution initially contains water and 50 to 95% by weight of lactam based on the total weight of water and lactam in the solution, and further contains 0.1 to 40% by weight of a crosslinked phenolic polymer based on the amount of lactam in the solution, wherein the lactam is ε-caprolactam, and wherein the crosslinked phenolic polymer is lignin.

14. The thermoplastic molding composition according to claim 13, wherein the polyamide in component A is polyamide 6.

15. The thermoplastic molding composition of claim 14, wherein component A is obtained by a method involving the ring-opening polymerization of an aqueous solution of hydrated ε-caprolactam, wherein water is removed, the aqueous solution initially containing 50 to 95% by weight of ε-caprolactam based on the total weight of water and caprolactam in the solution and further containing 0.1 to 40% by weight of lignin based on the amount of ε-caprolactam in the solution.

16. Use of the thermoplastic molding composition according to any one of claims 13-15 in the formation of molded articles, fibers or foils.

17. A molded article, fiber, or foil made from the thermoplastic molding composition of any one of claims 13-15.

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