Patent Application
20240254316
Plastic recyclates are a growing market and an important element in the circular economy of raw materials, with the objective ideally being for recyclates to replace virgin plastics with an identical or at least comparable property profile. However, recyclate from the production of plastics parts (so-called “post-industrial” recyclates) and from collections of used plastics (so-called “post-consumer” recyclates) differ chemically from virgin plastics. During the initial processing steps (e.g., by compounding, extrusion or injection moulding) and the application often over many years and in demanding fields of use (e.g., high temperatures and/or UV light), irreversible changes occur in the polymer chains due to mechano-chemical, chemical or light-induced processes (see for example R. Pfaendner et al., Angew. Makromol. Chemie 1995, 232, 193-227, R. Pfaendner, Kunststoffe International 12/2015, 41-44, J. Pospisil et al., Pol. Degr. Stab. 1995, 48, 351-358, La Mantia, Macromol. Symp. 135, 157-165 (1998)). Radical reactions in the presence of oxygen, generally referred to as autoxidation, generate new chemical groups in the polymer chain and/or change the composition of the polymer at molecular level. The chemical modifications resulting from is the damage process and the ageing process are mainly the formation of hydroperoxide groups, aliphatic carbonyl groups, unsaturated carbonyl groups, alcohol groups, acid groups, ester groups and peracid groups, i.e., structures that usually are not present in virgin polyolefins, for example, and are formed as a result of oxidation processes (J. Pospisil et al. Macromol. Symp. 135, 247-263 (1998)). Furthermore, recyclates often contain unsaturated structures, i.e., vinylene, vinylidene and vinyl groups, wherein the former may even be present in conjugated form. Unsaturated structures develop here by chain cleaving and disproportionation reactions (H. Hinsken et al., Pol. Degr. Stab. 1991, 34, 279-293). The concentration of these newly formed groups increases with the processing intensity (process control, shear strain, temperature), the field of application (UV light, high temperatures, contact media) and the application time. In addition, the formation of these structures may be catalyzed in oxidation processes and subsequent reactions by metals and by pigments.
The structural inhomogeneities of a recyclate influence the plastic properties, such as the mechanical properties or the morphology. Due to the newly formed chemical structures, recyclates or pre-damaged plastics are more sensitive to oxidation than virgin material, as these structures act as initiator sites for further oxidation or as prodegradants (A. S. Maxwell, Pol. Eng. Sci. 2008, 381-385, I. H. Craig, J. R. White, J. Mater. Sci. 2006, 41, 993-1006, S. Luzuriaga et al. Pol. Degr. Stab. 2006, 91, 1226-1232).
Furthermore, it has been demonstrated that the degradation rate of a polymer depends on the concentration of chromophores “impurities” (M. S. Rabello, J. R. White, Polym. Degr. Stab. 56, 55 (1997)). The concentration of the described chemical structures in the recyclates may increase here by several orders of magnitude compared to the virgin material.
To achieve an improvement in the quality of plastic recyclates, post-stabilization with selected stabilizers such as antioxidants is an essential method. The stabilizers used protect is the recyclate from further oxidative (or photooxidative) damage or at least delay it. Since virgin plastics and plastic recyclates differ significantly chemically as described and plastic recyclates are more sensitive to oxidation due to the described pre-damage and initiator sites, it is a challenging task to develop efficient stabilizers for an efficient stabilization of plastic recyclates. Due to the described structural deviations of the recyclate and the virgin material, the optimized stabilizer composition for a recyclate also differs from the stabilization composition of the virgin material (see e.g., R. Pfaendner, Kunststoffe International 12/2015, 41-44).
Due to the nowadays recognized differences between virgin plastics and plastic recyclates, special recyclate stabilizer compositions are known and also available as commercial products (e.g., Recyclobyk products from the company BYK-Chemie GmbH, Wesel). Known technical stabilization solutions that take into account the requirements of recyclates are described, for example, in the following patents/patent applications: Stabilization composition consisting of a phenolic antioxidant, a phosphite and a fatty acid salt (EP 0662101).
Stabilization composition consisting of a phenolic antioxidant, a phosphite and a metal oxide such as calcium oxide (U.S. Pat. Nos. 6,525,158, 6,251,972). Stabilization composition consisting of a phenolic antioxidant and a polyfunctional epoxy (EP 0702704).
Stabilization by a macrocyclic piperidine (U.S. Pat. No. 5,789,470).
Stabilization composition consisting of a secondary aromatic amine and a polyfunctional epoxide (WO 97/30112).
Decolourization of damaged polyolefins by a hydroxylamine (EP 0470048)
Mixture of antioxidants, lubricants, anti-blocking agents, UV stabilizers and antistatic agents for recyclate films (DD 288161)
Stabilization composition for mixed plastics consisting of a phenolic antioxidant and a phosphite/phosphonite (EP 0506614)
In more recent times, stabilization systems for recyclates have also been described which are based in particular partly or completely on renewable raw materials and contain selected sugar derivatives as active components:
Stabilizing composition containing alditols or cyclitols (WO 2019063550)
Stabilizing composition containing compounds capable of reacting with carbonyl groups and primary and/or secondary antioxidants (WO 2020152337)
Stabilizing composition containing substituted sugar molecules (WO2020193563)
Furthermore, sulphur-containing amino acids have been described as components in virgin plastics:
U.S. Pat. Nos. 3,859,250 and 510,458: Stabilization of butadiene-styrene block copolymers with a sulphur-containing amino acid
EP 062362: Stabilization of PVC by amino acid-metal complexes
GB 2562466, WO 2018202791: Stabilization of polymers and hot-melt adhesives by antioxidants and buffer agents, wherein metal phosphates and amino acids are mentioned as buffer substances.
Today, it may be assumed that the importance of stabilization systems made from renewable raw materials will increase in the future, as will the importance of polymers made from renewable raw materials, as they are able to achieve a favourable ecological balance through a reduced CO2 input from the raw materials and thus contribute to decarbonization.
However, for the long-term stabilization of plastics, e.g., at elevated temperatures, sulphides such as thioesters or disulphides are often used as synergists (e.g., C. Kröhnke et al, Antioxidants in Ullman's Encyclopedia of Industrial Chemistry). These thiosynergists, e.g., in the form of distearyl dithiopropionate, have also been exemplified in some cases as stabilizers for recyclates (e.g., EP 0506614, A. Hermann et al, Kunststoffe 2000, 90, 80-83, BE 1007218, JP 4793005, JP 2004217734, CN 108929482, CN 108148281, CN 102993538). For the post-stabilization of a plastic recyclate, however, it would be desirable if a powerful thiosynergist from renewable raw materials were available, so that it would be possible to offer a complete stabilization system consisting of primary and secondary antioxidants and for the long-term stabilization of polymers from renewable raw materials. This object could be achieved with the use of sulphur-containing amino acids such as methionine, cystine and cysteine for the post-stabilization of recyclates. Methionine is an amino acid found in many proteins and may be obtained by biotechnological processes (see e.g., T. Wilke. Appl. Microbiol. Biotechnol. 2014, 98, 9893-9914. Biotechnological possibilities also exist for cysteine (see e.g., M. Wada et al., Appl. Microbiol. Biotechnol. 2006, 73, 48-54).
Proceeding from the prior art, it was therefore the object of the present invention to provide new stabilizers or stabilizer compositions and new methods for stabilizing plastic recyclates which are highly effective, environmentally friendly and have a favourable cost structure.
This object is achieved with the features of the independent claims. The respective dependent claims describe advantageous developments.
In a first aspect, the invention thus relates to the use of at least one sulphur-containing amino acid for stabilizing thermoplastic recyclates, in particular against oxidative, thermal and/or actinic degradation.
Surprisingly, it could be found that the addition of sulphur-containing amino acids is particularly suitable for stabilizing thermoplastic recyclates against oxidative, thermal and/or actinic degradation. The stabilizers are cost-effective, environmentally friendly and have a high degree of efficacy.
According to a preferred embodiment, the at least one sulphur-containing amino acid, in relation to the totality of the thermoplastic recyclates, is used in a weight ratio of 0.01 to 10.00 wt. %, preferably 0.02 to 5.00 wt. %, particularly preferably 0.05 to 2.00 wt. %.
According to a further preferred embodiment, the at least one sulphur-containing amino is acid is selected from the group consisting of methionine or a methionine derivative or cystine, as well as alkali, alkaline earth, Al or Zn salts thereof.
Exemplary sulphur-containing amino acids have the following structures:
Methionine and/or cystine is very particularly preferred.
It is particularly advantageous if the at least one sulphur-containing amino acid is used in combination with at least one primary and/or secondary antioxidant, preferably in a weight ratio of 10:1 to 1:10, more preferably 5:1 to 1:5, particularly preferably 2:1 to 1:2.
Advantageously, the at least one primary antioxidant is selected here from the group consisting of phenolic antioxidants, (semi-)aromatic amines, hydroxylamines, lactones and isoindolo[2,1-A]quinazolines and mixtures and combinations thereof.
Primary antioxidants act as H-donors and as radical scavengers and thus interrupt the radical autoxidation process in polymers. Suitable primary antioxidants are phenolic antioxidants, (semi-)aromatic amines, hydroxylamines and lactones.
Suitable phenolic antioxidants are, for example:
Particularly preferred phenolic antioxidants are the following structures:
Further particularly preferred phenolic antioxidants are based on sustainable raw materials such as e.g., tocopherols (vitamin E), tocotrienols, tocomonoenols, carotenoids, hydroxytyrosol, flavonols such as e.g., chrysin, quercetin, hesperidin, neohesperidin, naringin, morin, camphor oil, fisetin, anthocyanins such as e.g., delphinidin and malvidin, curcumin, carnosic acid, carnosol, rosmarinic acid, resveratrol and tannins.
Suitable aminic antioxidants are, for example: N,N′-di-isopropyl-p-phenylene diamine, N,N′-di-sec-butyl-p-phenylene diamine, N,N′-bis(1,4-dimethylpentyl)-p-phenylene diamine, N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylene diamine, N,N′-bis(1-methylheptyl)-p-phenylene diamine, N,N′-dicyclohexyl-p-phenylene diamine, N,N′-diphenyl-p-phenylene diamine, N,N′-bis(2-naphthyl)-p-phenylene diamine, N-isopropyl-N′-phenyl-p-phenylene diamine, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylene diamine, N-(1-methylheptyl)-N′-phenyl-p-phenylene diamine, N-cyclohexyl-N′-phenyl-p-phenylene diamine, 4-(p-toluene sulfamoyl)diphenylamine, N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylene diamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxydiphenylamine, N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine, N-phenyl-2-naphthylamine, octylated diphenylamine, for example p,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-butyrylaminophenol, 4-nonanoylaminophenol, 4-dodecanoylaminophenol, 4-octadecanoylamino-phenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylaminomethyl-phenol, 2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, N,N,N′,N′-tetra-methyl-4,4′-diaminodiphenylmethane, 1,2-bis[(2-methyl-phenyl)amino]ethane, 1,2-bis(phenylamino)propane, (o-tolyl)biguanide, bis[4-(1′,3′-dimethylbutyl)phenyl]amine, tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl/tert-octyldiphenylamines, a mixture of mono- and dialkylated nonyldiphenylamines, a mixture of mono- and dialkylated dodecyldiphenylamines, a mixture of mono- and dialkylated isopropyl/isohexyl-diphenylamines, a mixture of mono- and dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, a mixture of mono- and dialkylated tert-butyl/tert-octylphenothiazines, a mixture of mono- and dialkylated tert-octylphenothiazinene, N-allylphenothiazine, N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene and mixtures or combinations hereof.
Preferred aminic antioxidants are: N,N′-diisopropyl-p-phenylenediamine, N,N′-di-sec-butyl-p-phenylenediamine, N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N,N′-bis(1-methylheptyl)-p-phenylenediamine, N,N′-dicyclohexyl-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine, N,N′-bis(2-naphthyl)-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine, N-cyclohexyl-N′-phenyl-p-phenylenediamine
Particularly preferred aminic antioxidants are the structures:
Preferred hydroxylamines or N-oxides (nitrones) are, for example, N,N-dialkylhydroxylamines, N,N-dibenzylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-distearylhydroxylamine, N-benzyl-α-phenylnitrone, N-octadecyl-α-hexadecylnitrone, as well as Genox EP (SI Group) according to the formula:
Suitable lactones are benzofuranones and indolinones such as e.g., 3-(4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butyl-benzofuran-2-one, 5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]benzofuran-2-one, 3,3′-bis[5,7-di-tert-butyl-3-(4-(2-hydroxyethoxy]phenyl)benzofuran-2-one), 5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one, 3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one, β-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butyl-benzofuran-2-one, 3-(3,4-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one, 3-(2,3-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one as well as lactones that additionally contain phosphite groups such as
A particularly preferred lactone has the following structure:
A further suitable group of antioxidants are isoindolol[2,1-A]quinazolines, such as
Preferably, the at least one secondary antioxidant is selected from the group consisting of phosphites, phosphonites, organo-sulphur compounds such as sulphides and disulphides, and mixtures and combinations thereof.
Secondary antioxidants primarily act as hydroperoxide decomposers in the stabilization of plastics.
Suitable secondary antioxidants are in particular phosphites or phosphonites such as triphenylphosphite, diphenylalkylphosphites, phenyldialkylphosphites, tri(nonylphenyl)phosphite, trilaurylphosphites, trioctadecylphosphite, distearylpentaerythritol diphosphite, tris-(2,4-di-tert-butylphenyl)phosphite, diisodecylpentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-di-cumylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, diisodecyloxypentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylenediphosphonite, 6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocine, bis(2,4-di-tert-butyl-6-methylphenyl)methylphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethylphosphite, 6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1.3,2-dioxaphosphocine. 2,2′2″-nitrilo[triethyltris(3,3″,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl)phosphite], 2-ethylhexyl(3,3′,5,5′-tetra-tert-butyl-1,1′-biphenyl-2,2′-diyl))phosphite, 5-butyl-5-ethyl-2-(2,4,6-tri-tert-butylphenoxy)-1,3,2-dioxaphosphirane.
Particularly preferred phosphites are:
A preferred phosphonite is:
s Suitable secondary antioxidants are furthermore organosulphur compounds such as sulphides and disulphides, e.g., distearylthiodipropionate, dilaurylthiodipropionate; ditridecyldithiopropionate, ditetradecylthiodipropionate, 3-(dodecylthio)-,1,1′-[2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propandiyl] propanoic acid ester. Preferred are the following structures:
A preferred embodiment provides that the thermoplastic recyclate is selected from the group consisting of
Particularly preferably, the thermoplastic recyclate is selected from the group consisting of polymers of olefins or diolefins, such as polyethylene, in particular LDPE, LLDPE, VLDPE, ULDPE, MDPE, HDPE and UHMWPE, metallocene-PE (m-PE), polypropylene, is polyisobutylene, poly-4-methyl-pentene-1, polybutadiene, polyisoprene, polycyclooctene, polyalkylene-carbon monoxide copolymers, as well as corresponding copolymers in the form of random or block structures, such as polypropylene-polyethylene (EP), EPM or EPDM, ethylene-vinyl acetate (EVA), ethylene-acrylic esters such as ethylene-butyl acrylate, ethylene-acrylic acid-glycidyl acrylate, and corresponding graft polymers, such as polypropylene-g-maleic anhydride, polypropylene-g-acrylic acid and polyethylene-g-acrylic acid.
Very particularly preferably, the one thermoplastic is a polyolefin recyclate. For example, the thermoplastic recyclate may be polypropylene, in particular a polypropylene recyclate homopolymer or copolymer, or polyethylene, in particular a polyethylene recyclate, for example HDPE, LDPE, LLDPE, MDPE, VLDPE or mixtures thereof. For example, polyethylene films from collections of recyclable materials often consist of a mixture of LDPE and LLDPE or of LDPE, LLDPE and HDPE film types. PP from collections of recyclable materials often contains mixtures of PP homo- and copolymers, which may contain up to 20% polyethylene.
Another particularly preferred group are recyclates of aliphatic polyesters from renewable raw materials, which are produced substantially from aliphatic dicarboxylic acids and aliphatic diols, from hydroxycarboxylic acids or lactones, such as polylactic acid (PLA), polyglycolic acid (PGA), polyhydroxybutyric acid (PHB), polyhydroxyvaleric acid (PHV), polyethylene succinate (PESu), polybutylene succinate (PBS), polyethylene adipate, poly(butylene succinate-co-adipate) (PBSA) or polycaprolactone (PCL).
In addition, the compositions may contain other additives selected from the group consisting of UV absorbers, light stabilizers, in particular the hindered amines as light (HALS) and long-term heat stabilizers (HAS), metal deactivators, filler deactivators, antiozonants, nucleating agents, antinucleating agents, transparency improvers (clarifiers), impact modifiers, plasticizers, lubricants, rheology modifiers, thixotropic agents, chain extenders, processing aids, demoulding aids, flame retardants, pigments, dyes, optical brighteners, antimicrobial agents, antistatic agents, slip agents, antiblocking agents, coupling agents, crosslinking agents, anti-crosslinking agents, hydrophilizing agents, hydrophobicizing agents, is surface modifiers, hydrolysis stabilizers, adhesion promoters, dispersing agents, compatibilizers, oxygen scavengers, acid scavengers, acetaldehyde and formaldehyde scavengers, blowing agents, degradation additives, defoaming agents, odour scavengers, odour-improving substances, PVC heat stabilizers, marking agents, antifogging agents, gloss improvers, mattifying agents, additives for increasing the electrica; and/or thermal conductivity, repellants, fillers and reinforcing agents are used.
In a preferred embodiment the recyclate compositions contain in particular hindered amines as light and long-term heat stabilizers, fillers, acid scavengers, polyol co-stabilizers or compatibilizers.
Suitable fillers and reinforcing materials are, for example, synthetic or natural materials such as calcium carbonate, silicates, glass fibres, glass balls (solid or hollow), talc, mica, kaolin, barium sulfate, metal oxides and metal hydroxides, carbon black, graphite, carbon nanotubes, graphene, wood flour or fibres of natural products such as cellulose or synthetic fibres. Other suitable fillers are hydrotalcites or zeolites or layered silicates such as montmorillonite, bentonite, beidelite, mica, hectorite, saponite, vermiculite, ledikite, magadite, illite, kaolinite, wollastonite, attapulgite.
Suitable acid scavengers (“antiacids”) are salts of monovalent, divalent, trivalent or tetravalent metals, preferably alkali metals, alkaline earth metals, aluminium or zinc, in particular formed with fatty acids, such as calcium stearate, magnesium stearate, zinc stearate, aluminium stearate, calcium laurate, calcium behenate, calcium lactate, calcium stearoyl-2-lactate. Other classes of suitable acid scavengers are hydrotalcites, in particular synthetic hydrotalcites based on aluminum, magnesium and zinc, hydrocalumites, zeolites, alkaline earth oxides, in particular calcium oxide and magnesium oxide as well as zinc oxide, alkaline earth carbonates, in particular calcium carbonate, magnesium carbonate and dolomite as well as hydroxides, in particular brucite (magnesium hydroxide).
Suitable costabilizers are also polyols, in particular alditols or cyclitols. Polyols are, for example, pentaerythritol, dipentaerythritol, tripentaerythritol, short chain polyether polyols or polyester polyols, as well as hyperbranched polymers/oligomers or dendrimers with alcohol groups, for example
Preferably, the at least one alditol is selected from the group consisting of threitol, erythritol, galactitol, mannitol, ribitol, sorbitol, xylitol, arabitol, isomalt, lactitol, maltitol, altritol, iditol, maltotritol, and hydrogenated oligo- and polysaccharides having polyol end groups, and mixtures thereof. Particularly preferred is the at least one preferred alditol selected from the group consisting of erythritol, mannitol, isomalt, maltitol and mixtures thereof.
Examples of other suitable sugar alcohols are heptitols and octitols: meso-glycero-allo heptitol, D-glycero-D-altro heptitol, D-glycero-D-manno heptitol, meso-glycero-gulo heptitol, D-glycero-D-galacto heptitol (perseitol), D-glycero-D-gluco heptitol, L-glycero-D-gluco heptitol, D-erythro-L-galacto-octitol, D-threo-L-galacto-octitol.
In particular, the at least one cyclitol may be selected from the group consisting of inositol (myo, scyllo-, D-chiro-, L-chiro-, muco-, neo-, allo-, epi- and cis-inositol). 1.2.3.4-tetrahydroxycyclohexane, 1,2,3,4,5-pentahydroxycyclohexane, quercitol, viscumitol, bornesitol, conduritol, ononitol, pinitol, pinpollitol, quebrachitol, ciceritol, quinic acid, shikimic acid and valienol; myo-inositol is preferred here.
Other suitable costabilizers are ester and ether derivatives of the stated alditols or cyclitols, such as the following compounds:
Suitable UV stabilizers are, for example, compounds based on 2-(2′-hydroxyphenyl)benzotriazoles, 2-hydroxybenzophenones, esters of benzoic acids, acrylates, oxamides and 2-(2-hydroxyphenyl)-1,3,5-triazines.
Suitable 2-(2′-hydroxyphenyl)benzotriazoles are, for example, 2-(2′-hydroxy-5′methylphenyl)benzotriazole, 2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(5′-tert-butyl-2′-hydroxy-phenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl-5-chlorobenzotriazole, 2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxy-phenyl)benzotriazole, 2-(2′-hydroxy-4′-octyloxyphenyl)benzotriazole, 2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole, 2-(3′,5′-bis(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole, 2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-ylphenol]; the product of the transesterification of 2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazole with polyethylene glycol 300; [R—CH2CH2—COO—CH2CH2—]-2, where R=3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-ylphenyl, 2-[2′-hydroxy-3′-(α,α-dimethylbenzyl)-5′-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole-2-[2′-hydroxy-3′-(1,1,3,3-tetramethylbutyl)-5′-(α,α-dimethylbenzyl)phenyl]benzotriazole.
Suitable 2-hydroxybenzophenones are, for example, 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxy and 2′-hydroxy-4,4′-dimethyoxy derivatives of 2-hydroxybenzophenones.
Suitable acrylates are, for example, ethyl-α-cyano-β,β-diphenyl acrylate, isooctyl-α-cyano-β,β-diphenyl acrylate, methyl-α-carbomethoxycinnamate, methyl-α-cyano-β-methyl-p-methoxycinnamate, butyl-α-cyano-β-methyl-p-methoxycinnamate, methyl-α-carbomethoxy-p-methoxycinnamate and N-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.
Suitable esters of benzoic acids are, for example, 4-tert-butylphenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl)resorcinol, benzoyl resorcinol, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate.
Suitable oxamides are, for example, 4,4′-dioctyloxyoxanilide, 2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butoxanilide, 2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide, N,N′-bis(3-dimethylaminopropyl)oxamide, 2-ethoxy-5-tert-butyl-2′-ethoxanilide and mixtures thereof with 2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide, mixtures of o- and p-methoxy-disubstituted oxanilides and mixtures of o- and p-ethoxy-disubstituted oxanilides.
Suitable 2-(2-hydroxyphenyl)-1,3,5-triazines are, for example, 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl-1,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)-phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine, 2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxypropoxy)phenyl]-4,6-bis(2,4-dimethylphenyl-1,3,5-triazine, 2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxypropoxy)phenyl]-1,3,5-triazine, 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine, 2-{2-hydroxy-4-[3-(2-ethylhexyl-1-oxy)-2-hydroxypropyloxy]phenyl}-4,6-bis(2,4-dimethylphenyl-1,3,5-triazine.
Suitable hindered amines are, for example, 1,1-bis(2,2,6,6-tetramethyl-4-piperidyl)succinate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensation product of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, linear or cyclic condensation products of N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylene diamine and 4-tert-octylamino-2,6-dichloro-1,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, 1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, linear or cyclic condensation products of N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylene diamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, the reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro-[4,5]decane and epichlorohydrin. The above-mentioned structures also include, in each case, the sterically hindered N—H, N-alkyl, such as N-methyl or N-octyl, the N-alkoxy derivatives, such as N-methoxy or N-octyloxy, the cycloalkyl derivatives, such as N-cyclohexyloxy and the N-(2-hydroxy-2-methylpropoxy) analogues. The above-mentioned structures also include, in each case, the sterically hindered N—H, N-alkyl, such as N-methyl or N-octyl, the N-alkoxy derivatives, such as N-methoxy or N-octyloxy, the cycloalkyl derivatives, such as N-cyclohexyloxy and the N-(2-hydroxy-2-methylpropoxy) analogues.
Preferred hindered amines furthermore have the following structures:
Preferred oligomeric and polymeric hindered amines have the following structures:
Another suitable light stabilizer is Hostanox NOW (manufacturer: Clariant SE) with the following general structure:
Compatibilizers are used, for example, in thermodynamically immiscible blends or also in recyclate mixtures and contain structural elements of the respective blend components that are mixed. Suitable compatibilizers for polyolefin mixtures are, for example, olefin block copolymers, consisting of ethylene, propylene and alpha-olefins such as 1-octene. Other compatibilizers, in particular for compatibilizing polar polymers such as PET or polyamides and non-polar polymers such as PP or PE, often contain reactive groups derived, for example, from maleic anhydride, acrylic acid, glycidyl acrylate or glycidyl methacrylate and are, for example, polypropylene-g-maleic anhydride, polyethylene-g-maleic anhydride, polypropylene-g-acrylic acid, polyethylene-g-acrylic acid, poly(ethylene-co-maleic anhydride),
SBS-g maleic anhydride SEBS-g maleic anhydride, polyethylene polyacrylate polyglycidyl methacrylate
Suitable dispersants are, for example:
Polyacrylates, for example copolymers with long-chain side groups, polyacrylate block copolymers, alkylamides: for example N,N′-1,2-ethanediylbisoctadecanamide sorbitan esters, for example monostearyl sorbitan esters, titanates and zirconates, reactive copolymers with functional groups, for example polypropylene-co-acrylic acid, polypropylene-co-maleic anhydride, polyethylene-co-glycidyl methacrylate, polystyrene-alt-maleic anhydride polysiloxanes: for example dimethylsilanediol-ethylene oxide copolymer, polyphenylsiloxane copolymer, amphiphilic copolymers: for example polyethylene-block-polyethylene oxide, dendrimers, for example dendrimers containing hydroxyl groups.
Suitable flame retardants are, in particular
Particularly suitable flame retardants are:
The preparation of suitable azo compounds is described, for example, in M. Aubert et. al. Macromol. Sci. Eng. 2007, 292, 707-714 or in WO 2008101845, the preparation of hydrazones and azines is described in M. Aubert et al., Pol. Adv. Technol. 2011, 22, 1529-1538, the preparation of triazenes is described in W. Pawelec et al., Pol. Degr. Stab. 2012, 97, 948-954. The synthesis of iminoxytriazines is described in WO 2014/064064.
Radical formers to be used in particular are selected here from the group consisting of
Typical examples of the aforementioned N-alkoxyamines of the indicated structure are:
The above-stated compounds are partly commercial products and are traded under the following trade names: FLAMESTAB NOR 116®, TINUVIN NOR 371®, IRGATEC CR 76 ® from BASF SE, Hostavin NOW® from Clariant or ADK Stab LA 81 ® from Adeka. Dicumyl and polycumyl are commercial products available, for example, from United Initiators.
A particularly preferred example of a phosphinate is constituted by the commercially is available products Exolit OP® from Clariant SE.
Further preferred phosphorus-containing flame retardants are metal salts of hypophosphorous acid having a structure according to the formula
Some of the above-mentioned salts of hypophosphorous acid are commercially available, e.g., under the name Phoslite® from Italmatch Chemicals.
Another preferred group of phosphorus-containing flame retardants are phosphonates or diaryl phosphonic acid esters of a structure according to the following formula:
Corresponding structures may also be in the form of phosphonate oligomers, polymers and co-polymers. Linear or branched phosphonate oligomers and polymers are known from the prior art. For branched phosphonate oligomers and polymers, reference is made to US patents U.S. Pat. Nos. 2,716,101, 3,326,852, 4,328,174, 4,331,614, 4,374,971, 4,415,719, 5,216,113, 5,334,692, 3,442,854, 6,291,630 B1, 6,861,499 B2 and 7,816,486 B2. For phosphonate oligomers, reference is made to US patent applications US 2005/0020800 A1, US 2007/0219295 A1 and US 2008/0045673 A1. With regard to linear phosphonate oligomers and polymers, reference is made to U.S. Pat. Nos. 3,946,093, 3,919,363, 6,288,210B1, 2,682,522 and 2,891,915.
Phophonates are available, for example, under the trade name Nofia® from FRX Polymers.
Another preferred group of phosphorus-containing flame retardants are compounds based on oxaphosphorine oxide and their derivatives with, for example, the following structures:
Products based on oxophosphorine oxide are, for example, available under the trade name Ukanol® from Schill und Seilacher GmbH. Further compounds may be prepared, for example, according to patent specifications WO 2013020696, WO 2010135398, WO03070736, WO2006084488, WO 2006084489, WO 2011000019, WO 2013068437, WO 2013072295.
Other suitable phosphorus-containing flame retardants are cyclic phosphonates of a structure according to one of the following formulas:
Cyclic phosphonates are available, for example, from the company Thor GmbH under the trade name Aflammit® or may be prepared according to EP 2450401.
Other synergistic phosphorus-containing flame retardants are phosphacenes, in particular polymeric phosphacenes. A corresponding product is available, for example, under the name SPB-100 from Otsuka Chemicals.
Preferred nitrogen-containing flame retardants are melamine polyphosphate, melamine cyanurate, melamine metal phosphates, poly-[2,4-(piperazin-1,4-yl)-6-(morpholin-4-yl)-1,3,5-triazine] and ammonium polyphosphate. These compounds are commercial products and are available under the trade names Melapur® from BASF SE, Budit® from Budenheim Chemische Fabrik, Exolit® from Clariant, Safire® from Huber Chemicals or MCA PPM Triazine from MCA Technologies GmbH.
c) Preferred Sulphur-Containing Flame Retardants are, for Example, the Following Compounds
Very particularly preferred flame retardants are halogen-free and are the following compounds:
Suitable lubricants and processing aids are, for example, polyethylene waxes, polypropylene waxes, salts of fatty acids such as calcium stearate, zinc stearate or salts of montan waxes, amide waxes such as erucic acid amide or oleic acid amides, fluoropolymers, silicones or neoalkoxytitanates and zirconates.
Suitable heat stabilizers, in particular for PVC recyclates, are for example metal soaps of divalent metals such as Ba, Zn, Ca, e.g., zinc stearate, calcium stearate, organo tin compounds, e.g., methyl and octyl tin compounds such as dioctyl tin bis isooctyl thioglycolate or dioctyl tin maleate aminouracils, aminocrotonic acid esters, perchlorate salts and, as co-stabilizers, phosphites, epoxides, polyols, diketones, dihydropyridines, hydrotalcites, zeolites.
Suitable pigments may be inorganic or organic in nature. Inorganic pigments are, for example, titanium dioxide, zinc oxide, zinc sulfide, iron oxide, ultramarine, carbon black; organic pigments are, for example, anthraquinones, anthanthrones, benzimidazolones, quinacridones, diketopyrrolopyrroles, dioxazines, indanthrones, isoindolinones, azo compounds, perylenes, phthalocyanines or pyranthrones. Other suitable pigments are metal-based effect pigments or metal-oxide-based pearlescent pigments.
Suitable optical brighteners are, for example, bisbenzoxazoles, phenylcoumarins or bis(styryl)biphenyls, and in particular optical brighteners of the formulas:
Suitable filler deactivators are, for example, polysiloxanes, polyacrylates, in particular block copolymers such as polymethacrylic acid-polyalkylene oxide or polyglycidyl (meth)acrylates and their copolymers, for example with styrene, and epoxides, for example of the following structures:
Suitable antistatic agents are, for example, ethoxylated alkylamines, fatty acid esters, alkyl sulfonates and polymers that form a co-continuous network with the polymer matrix, such as polyetheramides, polyesteramides, polyether ester ramides or polyether block copolymers, optionally with the addition of ionically conducting metal salts.
Suitable antiozonants are the above-mentioned amines such as N,N′-diisopropyl-p-phenylenediamine, N,N′-di-sec-butyl-p-phenylenediamine, N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,N′-dicyclohexyl-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine, N-cyclohexyl-N′-phenyl-p-phenylenediamine.
Suitable rheology modifiers e.g., for the preparation of controlled rheology polypropylene (CR-PP) are, for example, peroxides, alkoxyamine esters, oxyimide sulfonic acid esters and in particular the following structures:
Suitable additives for the molecular weight build-up of polycondensation polymers (chain is extenders) are diepoxides, bis-oxazolines, bis-oxazolones, bis-oxazines, diisocyanates, dianhydrides, bis-acyl lactams, bis-maleimides, dicyanates, carbodiimides and polycarbodiimides. Other suitable chain extenders are polymeric compounds, such as polystyrene-polyacrylate-polyglycidyl (meth)acrylate copolymers, polystyrene-maleic anhydride copolymers and polyethylene-maleic anhydride copolymers.
Suitable additives for increasing electrical conductivity are, for example, the aforementioned antistatic agents, carbon black and carbon compounds such as carbon nanotubes and graphene, metal powders, such as for example copper powder, and conductive polymers, such as polypyrroles, polyanilines and polythiophenes.
Suitable infrared-active additives are, for example, aluminosilicates, hydrotalcites or colouring agents such as phthalocyanines or anthraquinones.
Suitable crosslinking agents are, for example, peroxides like dialkyl peroxides, alkylaryl peroxides, peroxyesters, peroxycarbonates, diacylproxides, peroxyketals, silanes, such as e.g., vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltris(2-methoxyethoxy)silane, 3-methacryloyloxypropyltrimethoxysilane, vinyldimethoxymethylsilane or ethylene-vinylsilane copolymers.
Suitable prodegradants are additives that specifically accelerate or control the degradation of a polymer in the environment. Examples are transition metal fatty acid esters, e.g., of manganese or iron, which accelerate an oxidative and/or photooxidative degradation for example of polyolefins or enzymes which induce a hydrolytic degradation for example of is aliphatic polyesters.
Suitable chemical blowing agents are, for example, azo compounds such as
Suitable slip agents include amide waxes such as erucic acid amide or oleic acid amide.
Suitable anti-blocking agents are, for example, silica, talc or zeolites.
Suitable antifogging additives are for example ethoxylated sorbitan esters, ethoxylated fatty acid alcohols or ethoxylated alkylamine esters.
Suitable biocides are, for example, quaternary ammonium salts or silver salts, colloidal silver or silver complexes or also derivatives of natural substances such as chitosan
Suitable aldehyde scavengers are amines, hydroxylamines, polyvinyl alcohol, zeolites or cyclodextrins, suitable formaldehyde scavengers are melamine derivatives such as benzoguanamine or urea derivatives such as allantoin.
Suitable odour-binding or odour-preventing substances are silicates such as calcium silicate, zeolites or salts of hydroxy fatty acids such as zinc riceneolate.
Suitable marking agents are, for example, fluorescent dyes or rare earths.
Suitable nucleating agents are talc, alkali or alkaline earth salts of mono- and polyfunctional carboxylic acids, such as benzoic acid, succinic acid, adipic acid, for example sodium benzoate, zinc glycerolate, aluminium hydroxy-bis(4-tert-butyl)benzoate, 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate, as well as trisamides and diamides, such as trimesic acid tricyclohexylamide, trimesic acid tri(4-methylcyclohexylamide), trimesic acid tri(tert.butylamide), N,N′,N″-1,3,5-benzenetriyltris(2,2-dimethyl-propanamide) or 2,6-naphthalenedicarboxylic acid dicyclohexylamide.
Suitable antinucleating agents are azine dyes such as nigrosine or ionic liquids,
Suitable additives for increasing the thermal conductivity of plastic recyclates are, for example, inorganic fillers such as boron nitride, aluminium nitride, aluminium oxide, aluminium silicate, silicon carbide but also carbon nanotubes (CNT).
Suitable impact modifiers are usually selected for the particular recyclate and are selected for example from the group of functionalized or non-functionalized polyolefins, such as ethylene copolymers such as EPDM or maleic anhydride or styrene-acrylonitrile-modified EPDM, glycidyl-methacrylate-modified ethylene-acrylate copolymers or also ionomers, core-shell polymers for example based on MBS (methacrylate-butadiene-styrene copolymer) or acrylester-polymethyl methacrylate, thermoplastische elastomers (TPE) for example based on styrene-block copolymers (styrene-butadiene (SB), styrene-butadiene-styrene (SBS) optionally hydrated (SEBS) or modified by maleic anhydride (SEBS-g-MAH), thermoplastic polyurethanes, copolyesters or copolyamides.
Suitable demoulding aids are, for example, silicones, soaps and waxes such as montan waxes.
In another aspect, the present invention relates to a thermoplastic recyclate composition containing or consisting of at least one thermoplastic recyclate, and at least one sulphur-containing amino acid.
According to a preferred embodiment, the at least one sulphur-containing amino acid, in relation to the totality of the thermoplastic recyclates, is used in a weight ratio of 0.01 to 10.00 wt. %, preferably 0.02 to 5.00 wt. %, particularly preferably 0.05 to 2.00 wt. %.
Preferably, the at least one sulphur-containing amino acid is selected from the group consisting of methionine or a methionine derivative or cystine, as well as their alkali, alkaline earth, Al or Zn salts.
The thermoplastic recyclate composition according to the present invention may additionally contain at least one primary and/or secondary antioxidant.
With regard to specific embodiments concerning the content and/or type and nature of the respective sulphur-containing amino acids or the further additives, reference is made to the above explanations.
The present invention also relates to a stabilizer composition for stabilizing thermoplastic recyclates, in particular against oxidative, thermal and/or actinic degradation, consisting of at least one sulphur-containing amino acid, wherein the at least one sulphur-containing amino acid is preferably selected from the group consisting of methionine or a methionine derivative or cystine, as well as alkali, alkaline earth, Al or Zn salts thereof, as well as at least one primary and/or secondary antioxidant.
According to a preferred embodiment, the totality of the at least one sulphur-containing amino acid to the totality of the at least one primary and/or secondary antioxidant is present in a weight ratio of 10:1 to 1:10, further preferably 5:1 to 1:5, particularly preferably 2:1 to 1:2.
The present invention also relates to a masterbatch or a concentrate containing 10 to 90 wt. % of a stabilizer composition according to any one of the two preceding claims, and 90 to 10 wt. % of a thermoplastic, in particular a plastic recyclate, a virgin plastic or a mixture thereof.
Another aspect of the present invention relates to a moulding compound or moulded part producible from a thermoplastic recyclate composition according to the invention, in particular a polyolefin recyclate composition, in particular in the form of injection moulded parts, sheets or foils, foams, fibres, cables and tubes, profiles, hollow bodies, tapes, membranes, such as geomembranes, or adhesives, which are produced via extrusion, injection moulding, blow moulding, calendering, pressing methods, spinning processes, rotomoulding, for example
A further aspect of the present invention relates to a method for the stabilization, in particular for the oxidative, thermal and/or actinic stabilization of thermoplastic recyclates by addition, additivation or incorporation of at least one sulphur-containing amino acid, a stabilizer composition according to the invention, or a masterbatch according to the invention in a thermoplastic recyclate.
The present invention additionally relates to the use of the thermoplastic recyclate composition according to the invention for the production of moulded parts, in particular in the form of injection moulded parts, sheets or films, foams, fibres, cables and tubes, profiles, hollow bodies, tapes, membranes, such as geomembranes, or adhesives, which are is produced via extrusion, injection moulding, blow moulding, calendering, pressing methods, spinning processes, rotomoulding, for example
Preferably, the sulphur-containing amino acid, the stabilizer composition or the masterbatch, which may each be present as a powder, liquid, oil, compacted, on a carrier material, as granules, solution or flakes, is mixed with the polymer to be stabilized, and the polymer matrix is transferred into the melt and then cooled. Alternatively, it is also possible for this purpose to introduce the sulphur-containing amino acid, the stabilizer composition or the masterbatch in a molten state into a polymer melt.
In the event that further components are added to the polymer composition, these may be added to the polymers separately, in the form of liquids, powders, granules or compacted products, or together with the sulphur-containing amino acid, the stabilizer composition or the masterbatch as described above.
The incorporation of the sulphur-containing amino acid, the stabilizer composition or the masterbatch and optionally the additional additives into the plastic is carried out by conventional processing methods, preferably by mixers, kneaders or extruders. Preferred processing machines are extruders such as single screw extruders, twin screw extruders, planetary roller extruders, ring extruders, and co-kneaders, which are preferably equipped with vacuum degassing. The processing may take place here under air or, if necessary, under inert gas conditions.
The plastics compositions containing the sulphur-containing amino acid, the stabilizer composition or the masterbatch may be processed by conventional plastics processing methods in continuous and discontinuous processes, such as extrusion, calendering, blow moulding, pultrusion, injection moulding, pressing, transfer moulding, casting, blow moulding, rotational moulding, thermoforming, sintering, foaming or also by additive manufacturing processes for the production of granular material, moulded parts, semi-finished products, fibres and films.
Suitable extruders are piston extruders and screw extruders, single-screw extruders, twin-screw extruders, multi-screw extruders, planetary roller extruders, in particular for the production of plastics granular materials, pipes, rods, tubes, profiles, sheathing, board, films, V-belts, toothed belts, seals, foam boards (XPS), fibres and filaments for additive manufacturing processes.
Suitable injection moulding machines may be hydraulic or electromechanical and may comprise multi-component injection moulding and in-mould processes.
Moulded parts produced by injection moulding are, for example, bottles, containers, screw-top vessels, crates, barrels, buckets, pallets, technical parts for cars and transport such as is bumpers, trim parts, handles, headlight covers, fittings and functional parts, electrical and electronic applications such as housing parts and accessories for televisions, computers, mobile phones, washing machines, dishwashers, coffee machines, drills, plug connections, storage media, household, leisure and sporting articles such as planters, clothes hangers, toy figures, model making parts, components for furniture such as brackets.
Parts produced by blow moulding are in particular hollow bodies such as bottles, fuel tanks, canisters, washing water tanks and expansion tanks.
Parts produced by rotational moulding are in particular tanks such as fuel oil tanks, and rainwater tanks, housings for machines, transport containers, leisure and water sports articles such as kayaks Calendering is used in particular to produce films such as decorative films, wallpapers and floor coverings.
Additive manufacturing processes include, for example, binder jetting (BJ), laser sintering (LS), selective laser melting (SLM), electron beam melting (EBM), fused deposition modelling (FDM), fused filament fabrication (FFF), multi-jet modelling (MJM), poly-jet modelling (PJM), layer laminated manufacturing (LLM), thermal transfer sintering (TTS), digital light processing (DLP),
The present invention is described in greater detail with reference to the following examples, without limiting the present invention to the specific examples presented.
To test the effect of the stabilizer composition according to the invention, a post-consumer polypropylene recyclate made from ground-up battery boxes (supplier: BSB Braubach) was circulated in the melt at 210° C. in a twin-screw micro extruder (Micro 5 cc, manufacturer DSM) in continuous mode at 200 rpm for 30 minutes. After 10/20/30 minutes, the force take-up is measured. The force is a measure of the toughness of the melt and thus a measure of the molecular weight. The higher the remaining force, the lower the degradation of the polymer and the higher the polymer stability or the effect of the stabilizer addition. The mean value of the residual force from 2 tests is given in each case.
In a second series of tests, the PP recyclate was processed with further compositions according to the invention analogous to Examples 1-6 and the following results were obtained:
Compared to the comparative example, it is clear that combinations of the sulphur-containing amino acid of the invention both with primary antioxidants (AO) and secondary antioxidants (P) provide significant stabilization against oxidative degradation of recyclates.
In a further series of tests, the PP recyclate was processed exclusively with the addition of a sulphur-containing amino acid analogous to Examples 1-6 and the following results were obtained:
It is shown that the addition of the sulphur-containing amino acid alone has a stabilizing effect on a recyclate, but that the synergistic combination with a secondary or primary antioxidant is advantageous.
Similarly, an LLDPE/LDPE film recyclate containing a combination of 0.25% cystine with 0.25% octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was processed at 200° C. for 30 minutes in continuous mode. Compared to the film recyclate without additive, there is an increased melt stability.
Similarly, a PLA recyclate from beverage cups containing a combination of 0.25% cystine with 0.25% octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was processed at 200° C. for 30 minutes in continuous mode. Compared to the recyclate without additive, there is an increased melt stability.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 205 168.5 | May 2021 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/063395 | 5/18/2022 | WO |
