Process for stabilizing halogen-free thermoplastic plastic recyclates, plastic composition. Stabilizer Composition and Use of the Stabilizer Composition

The present invention relates to a method for stabilizing halogen-free thermoplastic plastic recyclates against oxidative, thermal and / or actinic degradation. The present invention also relates to a correspondingly stabilized plastic composition, a stabilizer composition for stabilizing halogen-free thermoplastic plastic recyclates and uses thereof.

Recycled plastics are a growing market and an important element in the circular economy of raw materials, with recyclates ideally replacing new plastics with an identical or at least a comparable property profile. However, with recyclates it comes from the

Production of plastic parts (so-called "post industrial" recyclates) and especially of old plastics (so-called "post-consumer" recyclates) during the first processing steps (e.g. compounding, injection molding) and the application often over many years to irreversible changes in the polymer chain by mechano -chemical, chemical or light-induced processes (see e.g. R. Pfaendner et al., Angew. Makromol. Chemie 1995, 232, 193-227, J. Pospisil et al., Pol. Degr. Stab. 1995, 48, 351-358) . Radical reactions in the presence of oxygen, generally referred to as autoxidation, create new chemical groups in the polymer chain and / or change the composition of the polymer at the molecular level. The groups formed in the aging process are often carbonyl, aldehyde or acid groups, especially in the case of polyolefins such as polyethylene or polypropylene. The concentration of these newly formed groups increases with the time of use and the area of ​​use (UV light, high temperatures, contact media). The structural inhomogeneities of a recyclate influence the plastic properties, such as the mechanical properties. Furthermore, recyclates or previously damaged plastics are more sensitive to oxidation than new material, since degradation products act as initiator sites for further oxidation or as prodegradants (AS Maxwell, Pol. Eng. Sci. 2008, 381-385, IH Craig, JR White, J. Mater .. Sci. 2006, 41, 993-1006). In order to improve the quality of plastic recyclates, post-stabilization with selected stabilizers such as antioxidants is an essential method. The stabilizers used protect the recyclate from further oxidative (or photooxidative) damage or at least delay it. Due to the structural deviations of the recycled material and the new material described, the optimized stabilizer composition for a recycled material also differs from the stabilizing composition of the new material (see e.g. R. Pfaendner, Kunststoffe International 12/2015, 41-44).

Due to the differences between new plastic and recycled plastic, which are recognized today, special recyclate stabilizer compositions are known and are also available as commercial products (e.g. Recyclostab products from 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:

Stabilizing composition consisting of a phenolic antioxidant, a phosphite and a fatty acid salt (EP 0662101).

Stabilizing composition consisting of a phenolic antioxidant, a phosphite and a metal oxide such as calcium oxide (US 6525158, US 6251972).

Stabilizing composition consisting of a phenolic antioxidant and a polyfunctional epoxide (EP 0702704).

Stabilization by a macrocyclic piperidine (US 5789470).

Stabilizing composition consisting of a secondary aromatic amine and a polyfunctional epoxide (WO 97/30112).

Discoloration of damaged pololefins by a hydroxylamine (EP 0470048)

Mixture of antioxidants, lubricants, antiblocking agents, UV stabilizers and antistatic agents for recycled films (DD 288161)

Stabilizing composition for mixed plastics consisting of a phenolic antioxidant and a phosphite / phosphonite (EP 0506614)

Despite the known solutions for the post-stabilization of recyclates, there is still a need for particularly high-performance, environmentally friendly and inexpensive stabilizer compositions for recyclates which are obtained with the compositions according to the invention.

Previous recyclate stabilizers (see above) are modifications of stabilizers for new plastics, none of the combinations mentioned enable an interaction or reaction with those that often arise during aging / oxidation terminate in carbonyl groups. The present invention thus represents a new approach in the stabilization of plastic recyclates.

Claims

1. Process for stabilizing halogen-free thermoplastic

Plastic recyclates against oxidative, thermal and / or actinic degradation, in which

(A) at least one compound capable of reacting with carbonyl groups,

in combination with

(B) at least one primary antioxidant and / or

(C) at least one secondary antioxidant,

be introduced into a halogen-free thermoplastic recyclate, whereby no alditols and cyclitols are used.

2. The method according to claim 1, characterized in that the at least one compound capable of reacting with carbonyl groups is selected from the group consisting of primary aliphatic amines, secondary aliphatic amines, thiols, hydroxylamine ethers, hydroxylamine esters, hydrazines, oligomers or polymers with alcohol groups bound to aliphatic carbons such as polyvinyl alcohols and their copolymers with vinyl acetate,

Polyhydroxy (meth) acrylates, hydantoins and thiohydantoins.

3. The method according to any one of the preceding claims, characterized in that the at least one compound capable of reacting with carbonyl groups is selected from the group consisting of laurylamine, stearylamine, hexamethylenediamine, decanediamine, dodecanediamine, dilaurylamine, distearylamine, 1 -Dodecanethiol, 1- hexadecanethiol, polycaprolactone tetra-3-mercaptopropionate, polyvinyl alcohol with a weight average molecular weight of 1,000 to 50,000 g / mol, polyhydroxy (meth) acrylates with a weight average molecular weight of 1,000 to 50,000 g / mol, imidazolidine - 2,4-dione, as well as compounds with the following structures:

4. The method according to any one of the preceding claims, characterized in that the at least one primary antioxidant (B) is selected from the group consisting of phenolic antioxidants, lactones, hydroxylamines and mixtures thereof.

5. The method according to any one of the preceding claims, characterized in that the at least one secondary antioxidant (C) is selected from the group consisting of phosphorus compounds, in particular phosphites and phosphonites, organosulfur compounds, in particular sulfides and disulfides, and mixtures of this.

6. The method according to any one of the preceding claims, characterized in that at least one compound (A) capable of reacting with carbonyl groups, at least one primary antioxidant (B) and at least one secondary antioxidant (C) is introduced into the halogen-free thermoplastic recyclate will.

7. The method according to any one of the preceding claims, characterized in that component (A) in a weight ratio to component (B) and / or component (C) of 90:10 to 10:90, preferably from 80:20 to 20:80, particularly preferably from 60:40 to 40:60, is introduced into the halogen-free thermoplastic recycled plastic.

8. The method according to any one of the preceding claims, characterized in that in each case based on the total weight of the plastic recyclate and the component (A) to (C)

0.02 to 3.00% by weight, preferably 0.03 to 1.00% by weight, particularly preferably 0.02 to 0.50% by weight, in particular 0.10 to 0.30% by weight .-% of the at least one compound (A) capable of reacting with carbonyl groups, and

0.02 to 3.00% by weight, preferably 0.03 to 1.00% by weight, particularly preferably 0.02 to 0.50% by weight, in particular 0.05 to 0.20% by weight .-% of the at least one primary antioxidant (B) and / or

0.02 to 3.00% by weight, preferably 0.03 to 1.00% by weight, particularly preferably 0.02 to 0.50% by weight, in particular 0.05 to 0.20% by weight .-% of the at least one secondary antioxidant (C)

be introduced into the halogen-free thermoplastic plastic recyclate.

9. The method according to any one of the preceding claims, characterized in that components (A) and (B) and / or (C) are introduced into the halogen-free thermoplastic recycled material in that

the components (A) and (B) and / or (C) present as solids are mixed with the halogen-free thermoplastic plastic recyclate present as solids and the resulting mixture is melted and then cooled, or the components present as solids ( A) and (B) and / or (C) are melted and the resulting melt is introduced into a melt of the halogen-free thermoplastic recycled material.

10. The method according to any one of the preceding claims, characterized in that the halogen-free thermoplastic plastic recyclate is selected from the group consisting of

a) Recycled polymers made from olefins or diolefins, such as polyethylene, in particular LDPE, LLDPE, VLDPE, ULDPE, MDPE, HDPE and UHMWPE, metallocene PE (m-PE), polypropylene,

Polyisobutylene, poly-4-methyl-pentene-1, polybutadiene,

Polyisoprene, polycyclooctene, polyalkylene-carbon monoxide copolymers, as well as corresponding n 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,

b) recycled polystyrene, polymethylstyrene, polyvinylnaphthalene, styrene-butadiene (SB), styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene,

Styrene isoprene, styrene-isoprene-styrene (SIS), styrene-butadiene-acrylonitrile (ABS), styrene-acrylonitrile-acrylate (ASA), styrene-ethylene, styrene-maleic anhydride polymers including corresponding graft copolymers such as styrene on butadiene,

Maleic anhydride on SBS or SEBS, as well as graft copolymers of methyl methacrylate, styrene-butadiene and ABS (MABS), c) recycled polymers of unsaturated esters such as e.g.

Polyacrylates and polymethacrylates such as polymethyl methacrylate (PMMA), polybutyl acrylate, polylauryl acrylate, polystearyl acrylate, polyacrylonitrile, polyacrylamides, and corresponding copolymers such as polyacrylonitrile-polyalkyl acrylate,

d) Recycled polymers from unsaturated alcohols and derivatives, such as polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, e) Recycled polyacetals, such as polyoxymethylene (POM), and corresponding copolymers, such as copolymers with butanal,

f) Recycled polyphenylene oxides and blends of these with polystyrene or polyamides,

g) recycled polymers of cyclic ethers such as e.g.

Polyethylene glycol, polypropylene glycol, polyethylene oxide,

Polypropylene oxide,

h) recycled polyurethanes made from hydroxy-terminated polyethers or polyesters and aromatic or aliphatic isocyanates, in particular linear polyurethanes, polyureas,

i) Recycled polyamides such as polyamide-6, 6.6, 6.10, 4.6, 4.10, 6.12, 12.12, polyamide 11, polyamide 12 and (partially) aromatic polyamides such as polyphthalamides, e.g. made from

Terephthalic acid and / or isophthalic acid and aliphatic diamines or from aliphatic dicarboxylic acids such as adipic acid or sebacic acid and aromatic diamines such as 1,4- or 1,3-diaminobenzene,

j) recycled polyimides, polyamide-imides, polyether-imides,

Polyesterimides, poly (ether) ketones, polysulfones,

Polyether sulfones, polyarylsulfones, polyphenylene sulfide,

Polybenzimidazoles, polyhydantoins,

k) Recycled polyesters made from aliphatic or aromatic

Dicarboxylic acids and diols or from hydroxycarboxylic acids such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polypropylene terephthalate, polyethylene naphthylate, poly-1,4-dimethylocyclohexane phthalate, polyhydroxybenzoate,

Polyhydroxynaphthalate, polylactic acid,

L) recycled polycarbonates, polyester carbonates and blends of these such as PC / ABS, PC / PBT, PC / PET / PBT,

m) recycled cellulose derivatives, such as cellulose nitrate,

Cellulose acetate, cellulose propionate, cellulose butyrate,

n) and mixtures, combinations or blends of two or more of the aforementioned polymers.

11. Plastic composition containing or consisting of

(A) at least one compound capable of reacting with carbonyl groups,

in combination with

(B) at least one primary antioxidant and / or

(C) at least one secondary antioxidant,

in a halogen-free thermoplastic plastic recyclate, the plastic composition being free from alditols and cyclitols.

12. Plastic composition according to the preceding claim, characterized in that component (A) in a weight ratio to component (B) and / or component (C) of 90:10 to 10:90, preferably from 80:20 to 20:80, particularly preferably from 60:40 to 40:60, is contained in the plastic composition.

13. Plastic composition according to one of claims 11 to 12, characterized in that in each case based on the total weight of the plastic recyclate and the component (A) to (C)

0.02 to 3.00% by weight, preferably 0.03 to 1.00% by weight, particularly preferably 0.02 to 0.50% by weight, in particular 0.10 to 0.30% by weight .-% of the at least one compound (A) capable of reacting with carbonyl groups, and

0.02 to 3.00% by weight, preferably 0.03 to 1.00% by weight, particularly preferably 0.02 to 0.50% by weight, in particular 0.05 to 0.20% by weight .-% of the at least one primary antioxidant (B) and / or

0.02 to 3.00% by weight, preferably 0.03 to 1.00% by weight, particularly preferably 0.02 to 0.50% by weight, in particular 0.05 to 0.20% by weight .-% of the at least one secondary antioxidant (C)

are included.

14. Plastic composition according to one of claims 11 to 13, characterized in that at least one compound (A) capable of reacting with carbonyl groups, at least one primary antioxidant (B) and at least one secondary antioxidant (C) are contained.

15. Plastic composition ung according to one of claims 11 to 14, characterized in that the plastic composition additionally contains at least one additive which is selected from the group consisting of UV absorbers, light stabilizers, metal deactivators, filler deactivators, antiozonants,

Nucleating agents, anti-nucleating agents,

Impact modifiers, plasticizers, lubricants,

Rheology modifiers, thixotropic agents, chain extenders, optical brighteners, antimicrobial agents (e.g. biocides),

Antistatic agents, slip agents, antiblocking agents, coupling agents, crosslinking agents, branching agents, anti-crosslinking agents,

Hydrophilizing agents, hydrophobizing agents, adhesion promoters, dispersants, compatibilizers, oxygen scavengers, acid scavengers, blowing agents, degradation additives, defoaming agents, odor scavengers, marking agents, anti-fogging agents, additives to increase electrical conductivity and / or thermal conductivity, infrared absorbers or infrared absorbers - Reflectors, gloss improvers, matting agents, repellents, fillers, reinforcing agents and mixtures thereof.

16. Plastic composition according to one of claims 11 to 15, characterized in that the plastic composition additionally contains at least one additive which is selected from the group consisting of

a) Acid scavengers, preferably calcium stearate, magnesium stearate, zinc stearate, aluminum stearate, calcium stearate, calcium lactate, calcium stearoyl-2-lactate, hydrotalcites, especially synthetic hydrotalcites based on aluminum, magnesium and zinc, hydrocalumites, zeolites, alkaline earth oxides, especially calcium oxide and magnesium oxide, Alkaline earth carbonates, in particular

Calcium carbonate, magnesium carbonate and dolomite, and hydroxides, especially brucite,

b) light stabilizers, preferably light stabilizers from the group of hindered amines,

c) dispersants,

d) filler deactivators, and

e) mixtures thereof.

17. Plastic composition according to one of claims 11 to 16, characterized in that the at least one halogen-free thermoplastic plastic recyclate is a polyolefin recyclate, in particular a polypropylene or polyethylene recyclate.

18. Plastic composition according to one of claims 11 to 17, characterized in that the plastic composition can be produced using a method according to one of claims 1 to 10.

19. Molding compound or molded part producible from a plastic composition according to one of claims 11 to 18, in particular in the form of injection molded parts, foils, films, lacquers, coatings, foams, fibers, cables, pipes, profiles, hollow bodies, tapes, membranes e.g. geomembranes, lubricants, colorants and / or adhesives that are manufactured via extrusion, injection molding, blow molding, calendering, pressing processes, spinning processes and / or rotomoulding e.g. for the electrical industry, for the construction industry, for the transport industry, for medical applications, for household and electrical appliances, for vehicle parts, for consumer articles, for packaging, for furniture, for textiles.

20. Stabilizer composition for stabilizing halogen-free thermoplastic plastic recyclates against oxidative, thermal and / or actinic degradation, consisting of

(A) at least one compound capable of reacting with carbonyl groups,

in combination with

(B) at least one primary antioxidant and / or

(C) at least one secondary antioxidant,

wherein the stabilizer composition is free from alditols and cyclitols.

21. Stabilizer composition according to the preceding claim, characterized in that component (A) in a weight ratio to component (B) and / or component (C) of 90:10 to 10:90, preferably of 80: 20 to 20:80, particularly preferably from 60:40 to 40:60, is contained in the plastic composition.

22. Stabilizer composition according to one of the two preceding claims, characterized in that it consists of at least one compound (A) capable of reacting with carbonyl groups, at least one primary antioxidant (B) and at least one secondary antioxidant (C ) consists.

23. Stabilizer composition according to one of claims 21 to 23, characterized in that it consists of

(A) 90.00 to 10.00% by weight or 80.00 to 20.00% by weight, preferably 60.00 to 40.00% by weight, of at least one compound capable of reacting with carbonyl groups, with the exception of alditols and cyclitols,

in combination with

(B) 10.00 to 90.00% by weight, preferably 20.00 to 30.00% by weight, of at least one primary antioxidant and / or

(C) 10.00 to 90.00% by weight, preferably 20.00 to 30.00% by weight, of at least one secondary antioxidant

consists.

24. Use of a stabilizer composition according to one of claims 21 to 23 for stabilizing halogen-free thermoplastic plastics Re cyclates against oxidative, thermal and / or actinic degradation.