Method for producing and recycling carpets

Abstract

The invention relates to methods for producing carpets using carpet coating compositions and later recycling of said carpets by means of solvent treatment, characterised in that the carpet coating compositions contain one or more vinyl acetate-ethylene copolymers which are present in the organic solvent or in the mixture of organic solvents which is used for the solvent treatment during the recycling of the carpets, have a solubility of 35% to 95%, wherein the organic solvents are selected from the group comprising esters, ethers, alcohols, ketones and aliphatic or aromatic hydrocarbons.

Description

[0001] WP12402 / E

[0002] Methods for manufacturing and recycling carpets

[0003] The invention relates to methods for manufacturing and recycling carpets using carpet coating compositions containing polymers based on ethylene unsaturated monomers.

[0004] In the production of carpets, such as broadloom carpet or carpet tiles, the carpet pile is formed from tufts of fibers, which are inserted, for example, in loops into a woven or laid backing material (primary backing). The loops are only loosely attached to the backing material (tufted carpet). For needle-felt carpets, the fiber tufts are needled. In woven carpets, the fiber tufts are woven into the backing material. Common synthetic fibers are based on polypropylene (PP), polyester such as PET, or polyamide, for example, PA6. To improve the bond between the carpet pile and the backing material, a binder is applied to the reverse side of the backing material. For example, aqueous polymer dispersions can be applied as a foam or in an unfoamed state (precoat).Such aqueous polymer dispersions may be filled with fillers, for example chalk, and may contain other additives such as thickeners, dispersing agents, antistatic agents, flame retardants or foaming agents.

[0005] The carpet products obtained in this way can be equipped with an additional backing material (carpet backing, secondary backing) to improve dimensional stability. This is generally a woven fabric made of synthetic fibers, such as polypropylene or polyester. To bond the carpet backing to the carpet obtained after the primer coat, another bonding agent is applied. The aforementioned WP12402 / E can also be used for this purpose.

[0006] 2 aqueous polymer dispersions can be applied as foam or unfoamed (second coat or secondary coating).

[0007] For the meaningful reuse of materials from used carpets according to the circular economy strategy, simple and efficient carpet recycling processes are essential. One problem is that fiber materials, such as PP, PA6, or PET, often cannot be separated from the binders and any fillers in the carpet backing compositions with the desired purity, resulting in the fiber materials being recovered only in insufficient purity. Such binder and filler contamination can impair or even prevent downstream processing steps, such as depolymerization or the production of regranulate. Common methods for separating the fiber materials from carpet backing residues are generally associated with disadvantages or limitations.For example, alkaline separation processes are limited to fiber materials that do not hydrolyze under such conditions, and the pH-responsive binders required for these processes generally do not produce carpets with the required wet mechanical strength. Separation processes involving selective fiber dissolution require a specific solvent or solvent mixture for each fiber type and cleaning problem, with the range of solvents being limited by toxicological criteria.

[0008] A carpet recycling process in which the binder of the carpet backing is dissolved in solvents, thereby releasing fiber material, is known, for example, from US2008113146. For this purpose, US2008113146 used terpene-containing solvents and applied temperatures in the range of the boiling point of the terpene-containing solvents to dissolve polyolefin binders and separated the insoluble residues, WP12402 / E

[0009] 3. Fibers, from. The polymeric binders dissolved in the terpene-containing solvent were isolated and recycled as carpet binders. US 5,889,142 describes the extraction of nylon from carpet waste using caprolactam-water mixtures at elevated temperatures. US2014158276 of Fenbart describes a process for recycling carpets containing hot-water-soluble binders by repeatedly treating the carpets with hot steam in a chamber to dissolve the binders and directly irradiating the reverse side with hot steam through a multitude of nozzles. According to US 5,722,603, fiber recovery from carpets is achieved through numerous shredding steps and cleaning by sieve separation and washing, with fibers and backing material being separated from each other in a hydrocyclone. The addition of additives is recommended to improve particle wetting and separation.W09610054 describes methods for separating fiber material and carpet backing using softening agents, such as long-chain aliphatic diesters. Separating long-chain diesters from the binder fraction is difficult, and recycling the softening agents is energy-intensive. US 6610769 teaches carpet backing coatings based on copolymers of styrene, butadiene, and a mixture of acid monomers, whereby the backing can be completely separated from the fiber material in an aqueous alkaline solution of a nonionic surfactant using shear forces. However, solvent-based methods have been discarded.

[0010] US4278727 describes cellulosic nonwoven materials containing alkali-soluble, but water-resistant (under neutral to weakly acidic conditions) copolymers as binders, specifically acid-functionalized vinyl acetate-vinyl ester copolymers, which can be separated from the fiber material by alkaline treatment. Nonwovens are textile sheet materials, WP12402 / E

[0011] 4 such as nonwovens, in which fibers laid flat are bonded using a binder, and therefore not carpets.

[0012] Against this background, the task was to provide carpets that could be recycled using solvent treatment. The aim was to obtain recycled fibers in the purest possible form in the most efficient way possible, even under mild conditions such as room temperature during solvent treatment.

[0013] Surprisingly, it has been found that carpets can be recycled efficiently, even under very mild conditions such as room temperature, and that fibers of surprisingly high purity can be recovered if carpet coating compositions containing vinyl acetate-ethylene copolymers as binders are used in the manufacture of the carpets, which do not completely dissolve in the organic solvent or mixture of organic solvents used for solvent treatment in the recycling process.

[0014] The invention relates to methods for manufacturing carpets using carpet coating compositions and subsequently recycling these carpets by solvent treatment, characterized in that the carpet coating compositions contain one or more vinyl acetate-ethylene copolymers which have a solubility of 35% to 95% in the organic solvent or mixture of organic solvents used for solvent treatment during carpet recycling, wherein the organic solvents are selected from the group comprising esters, ethers, alcohols, ketones, and aliphatic or aromatic hydrocarbons. WP12402 / E

[0015] 5

[0016] Preferred organic solvents for solvent treatment are esters, ethers, alcohols, and ketones. Esters and ketones are particularly preferred. Esters are most preferred. The organic solvents preferably contain one or more oxygen-containing functional groups.

[0017] The alcohols preferably contain 1 to 7 and particularly preferably 2 to 5 carbon atoms. Examples of alcohols are methanol, ethanol, n-propanol, i-propanol, n-butanol, tert-butyl alcohol, allyl alcohol, 3-pentanol, benzyl alcohol, and tetrahydrofuryl alcohol. Preferred alcohols are tetrahydrofuryl alcohol and tert-butyl alcohol.

[0018] Esters are generally esters of carboxylic acids and alkyl alcohols, particularly esters of carboxylic acids with 2 to 6 carbon atoms and alkyl alcohols with 1 to 6 carbon atoms. Examples of esters are methyl acetate, butyl acetate, tert-butyl acetate, and especially ethyl acetate and cyclic esters (lactones) such as caprolactone or mevalonolactone. The ethers preferably contain 2 to 10 and particularly preferably 3 to 6 carbon atoms. Examples of ethers are tetrahydrofuran, 1,4-dioxane, glycol ethers, anisole, 4-methyltetrahydropyran (MTHP), pyrans, oxanes, 2-methyltetrahydrofuran (2-MFTHF), and cyclopentyl methyl ether.

[0019] The ketones preferably contain 3 to 7 and particularly preferably 3 to 5 carbon atoms. Examples of ketones are acetone, methyl ethyl ketone, 2-butanone, and 4-methyl-2-pentanone.

[0020] The aliphatic or aromatic hydrocarbons preferably contain 5 to 10 and particularly preferably 6 to 8 carbon atoms. The hydrocarbons preferably contain aromatic hydrocarbons or particularly preferably exclusively saturated carbon atoms. Examples of aliphatic hydrocarbons are cyclohexane and heptane. Examples of aromatic hydrocarbons are xylene and toluene.

[0021] Preferred examples of organic solvents are ethyl acetate, tetrahydrofuran, methyl ethyl ketone, and butyl acetate. Be-WP12402 / E

[0022] 6. Particularly preferred are ethyl acetate, tetrahydrofuran and methyl ethyl ketone. Ethyl acetate is most preferred.

[0023] Mixtures of organic solvents generally contain at least two organic solvents.

[0024] The organic solvents are preferably based on > 70 wt.%, particularly preferably on > 90 wt.% and most preferably exclusively on organic solvents selected from the group comprising esters, ethers, alcohols, ketones and aliphatic or aromatic hydrocarbons, based on the total weight of the organic solvents.

[0025] The organic solvents or mixtures of organic solvents have a boiling point of preferably 40°C to 180°C, particularly preferably 60°C to 160°C and most preferably 70°C to 120°C at a pressure of 1 bar.

[0026] The vinyl acetate-ethylene copolymers exhibit a solubility of 35% to 95%, preferably 40% to 93%, particularly preferably 50% to 90%, and most preferably 55% to 80% in the organic solvent. The determination of this solubility according to the invention is generally carried out by producing a polymer film from vinyl acetate-ethylene copolymers in the form of aqueous dispersions at 20°C and ambient pressure using a doctor blade, particularly with a layer thickness of 200 to 800 pm, and, after drying at 25°C under vacuum until constant weight is achieved, weighing a defined mass of the polymer film into an Erlenmeyer flask, adding a defined mass of solvent, and then heating under reflux at ambient pressure for 12 hours. After cooling to 20 °C and filtration, the resulting solution is concentrated and the remaining residue is dried until a constant weight is achieved.The solubility according to the invention is calculated from the mass distribution WP12402 / E.

[0027] 7. Ratio of the residue obtained so to the mass of the polymer film weighed into the Erlenmeyer flask, in percent.

[0028] Water may also be present during solvent treatment. For example, water can be added to the carpets during solvent treatment. The addition of water can occur before, after, or during the solvent treatment, either simultaneously or separately. Preferably, the carpets can be cleaned with water before the solvent treatment, and any water remaining in the carpet can be incorporated into the solvent treatment. This increases the efficiency of the process, as water remaining in the carpet after the cleaning step does not need to be removed in a further, time-consuming, and energy-intensive step.

[0029] The proportion of water in the solvent treatment is preferably < 30 wt.%, more preferably < 15 wt.%, particularly preferably < 5 wt.% and most preferably < 1 wt.%, based on the total weight of the organic solvents used for the solvent treatment. Most preferably, no water is added to the solvent treatment and / or dry carpets are used or the solvent treatment is water-free.

[0030] Vinyl acetate-ethylene copolymers are generally obtained by radical-initiated emulsion polymerization in aqueous medium of vinyl acetate, ethylene, and optionally one or more other comonomers. These other comonomers are generally different from vinyl acetate and ethylene.

[0031] Vinyl acetate-ethylene copolymers are based on vinyl acetate to a concentration of preferably 60 to 98 wt.% and particularly preferably 75 to 95 wt.%.

[0032] The vinyl acetate-ethylene copolymers are preferably based on 2 to 30 wt.% wt.% and particularly preferably 5 to 25 wt.% WP12402 / E

[0033] 8 on ethylene.

[0034] If necessary, up to 10 wt.%, preferably 0.1 to 10 wt.%, further comonomers can be copolymerized.

[0035] The values ​​given in wt. % refer to the total weight of the monomers and add up to 100 wt. %.

[0036] Examples of suitable additional comonomers are those from the group of vinyl esters with 3 to 12 carbon atoms in the carboxylic acid residue, such as vinyl propionate, vinyl laurate, and vinyl esters of alpha-branched carboxylic acids with 8 to 11 carbon atoms, such as VeoVa. R EH, VeoVa R 9 or VeoVa R10 (trade names of the company Resolution). Other examples are methacrylic acid esters or acrylic acid esters of unbranched or branched alcohols with 1 to 15 carbon atoms, such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, norbornyl acrylate. Further examples are vinyl halides such as vinyl chloride.

[0037] Further examples of suitable comonomers are auxiliary monomers: ethylene-unsaturated mono- and dicarboxylic acids, preferably acrylic acid, methacrylic acid, crotonic acid, fumaric acid and maleic acid; ethylene-unsaturated carboxylic acid amides and nitriles, preferably acrylamide and acrylonitrile; mono- and diesters of crotonic acid, fumaric acid and maleic acid such as the diethyl and diisopropyl esters, as well as maleic anhydride, ethylene-unsaturated sulfonic acids or their salts, preferably vinylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid.Other examples include pre-crosslinking comonomers such as polyethylene unsaturated comonomers, for example divinyl adipate, diallyl maleate, allyl methacrylate or triallyl cyanurate, or post-crosslinking comonomers, for example acrylamidoglycolic acid (AGA), methyl acrylamidoglycolic acid methyl ester (MAGME), N-methylolacrylamide (NMA), N-methylolmethacrylamide (NMMA), N-methylolallylcarbamate, alkyl ethers such as isobutoxy ether or esters of N-methylolacrylamide or N-methylol- WP12402 / E.

[0038] 9 methacrylamides and N-methylolallyl carbamate. Monomers with hydroxy or carboxyl groups are also suitable, such as methacrylic acid and acrylic acid hydroxyalkyl esters like hydroxyethyl, hydroxypropyl or hydroxybutyl acrylate or methacrylate, as well as 1,3-dicarbonyl compounds such as acetacetoxyethyl acrylate, acetacetoxypropyl methacrylate, acetacetoxyethyl methacrylate, acetacetoxybutyl methacrylate, 2,3-di(acetacetoxy)propyl methacrylate and acetoacetic acid allyl esters.

[0039] Suitable additional comonomers include, for example, epoxy-functional comonomers such as glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, and vinyl glycidyl ether. Further examples of suitable comonomers are silicon-functional comonomers such as acryloxypropyl tri(alkoxy)- and methacryloxypropyl tri(alkoxy)-silanes, vinyltrialkoxysilanes, and vinylmethyldialkoxysilanes, preferably with alkyl or alkoxy groups, each with 1 to 2 carbon atoms, for example, vinyltrimethoxysilane, vinyltriethoxysilane, and 3-methacryloxypropyltrimethoxysilane.

[0040] Preferably, up to 10 wt.%, in particular 0.1 to 10 wt.%, based on the total weight of the monomers, are copolymerized as auxiliary monomers.

[0041] Preferably, less than 3 wt.%, particularly preferably less than 1 wt.%, based on the total weight of the monomers, and most preferably no ethylene-unsaturated acid monomers are copolymerized. Ethylene-unsaturated acid monomers are, for example, the above-mentioned ethylene-unsaturated mono- and dicarboxylic acids, monoesters of fumaric acid and maleic acid, and ethylene-unsaturated sulfonic acids or their salts.

[0042] The vinyl acetate-ethylene copolymers are preferably not alkali-soluble, i.e., not soluble in aqueous alkaline solutions, especially not at pH values ​​> 8. WP12402 / E

[0043] 10

[0044] Preferably, no auxiliary monomers are copolymerized, in particular no post-crosslinking comonomers, no pre-crosslinking comonomers, no epoxy-functional comonomers, and no silicon-functional comonomers. Particularly preferably, no pre-crosslinking comonomers are copolymerized, in particular no polyethylene-unsaturated comonomers such as divinyl adipate, diallyl maleate, allyl methacrylate, or triallyl cyanurate. Polyethylene-unsaturated comonomers generally contain at least two ethylene-unsaturated groups, in particular two or three ethylene-unsaturated groups.

[0045] Preferably, up to 10 wt.%, more preferably 0.1 to 10 wt.%, and particularly preferably 0.1 to 5 wt.% of further comonomers are copolymerized, based on the total weight of the monomers. Most preferably, no further comonomers are copolymerized.

[0046] The monomers are selected such that the vinyl acetate-ethylene copolymers generally exhibit a glass transition temperature Tg of -20 to +30°C. The glass transition temperature Tg of the polymers can be determined using known methods such as DSC (Dynamic Differential Scanning Analysis, DIN EN ISO 11357-1 / 2). Tg can also be approximated using the Fox equation. According to Fox TG, Bull. Am. Physics Soc. 1, 3, page 123 (1956): 1 / Tg = xl / Tgl + x2 / Tg2 + ... + xn / Tgn, where xn represents the mass fraction (wt% / 100) of monomer n, and Tgn is the glass transition temperature in Kelvin of the homopolymer of monomer n. Tg values ​​for homopolymers are listed in Polymer Handbook 2nd Edition, J. Wiley & Sons, New York (1975).

[0047] Vinyl acetate-ethylene copolymers are generally produced by radical-initiated emulsion polymerization in water. The polymerization temperature is 40°C to WP12402 / E

[0048] 11

[0049] 120°C, preferably 60°C to 90°C. The polymerization is preferably carried out under pressure, in particular at a pressure between 5 bar and 120 bar.

[0050] Polymerization can generally be initiated using water-soluble or monomer-soluble initiators or redox-initiator combinations commonly used for emulsion polymerization. Examples of water-soluble initiators include the sodium, potassium, and ammonium salts of peroxodisulfuric acid, hydrogen peroxide, tert-butyl peroxide, tert-butyl hydroperoxide, potassium peroxodiphosphate, tert-butyl peroxopivalate, cumene hydroperoxide, isopropylbenzene monohydroperoxide, and azobisisobutyronitrile. Examples of monomer-soluble initiators include dicetyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, and dibenzoyl peroxide. The sodium, potassium, and ammonium salts of peroxodisulfuric acid and hydrogen peroxide are preferred. The aforementioned initiators are generally present in an amount of 0.001 to 2.0 wt.%, preferably 0.0015 to 1.0 wt.%, particularly preferably 0.002 to 0.5 wt.% and most preferably 0.0025 to 0.3 wt.%.-%, based on the total weight of the monomers, is used. The monomer conversion can be controlled as usual by adjusting the initiator dosage. The initiators are generally dosed in such a way as to ensure continuous polymerization.

[0051] Redox initiators are combinations of the aforementioned initiators and reducing agents. Suitable reducing agents are the sulfites and bisulfites of alkali metals and ammonium, for example, sodium sulfite; the derivatives of sulfoxylic acid such as zinc or alkali formaldehyde sulfoxylates, for example, sodium hydroxymethanesulfinate (Brüggolit FF); tartaric acid; and (iso)ascorbic acid. Sodium hydroxymethanesulfinate, tartaric acid, and (iso)ascorbic acid are preferred. The amount of reducing agent is generally 0.001 to 2.0 wt.%, preferably 0.0015 to 1.0 wt.%, and particularly preferably 0.002 wt.%.

[0052] 12 to 0.5 wt.% and most preferably 0.0025 to 0.3 wt.%, in each case based on the total weight of the monomers.

[0053] To control the molecular weight, regulating substances can be used during emulsion polymerization processes. If regulators are used, they are typically added in amounts between 0.001 and 5.0 wt%, based on the monomers to be polymerized, and dosed separately or premixed with reaction components. Examples of regulators are n-dodecyl mercaptan, tert. -Dodecyl mercaptan, mercaptopropionic acids or their alkali salts, such as iso-octylmercaptopropionate, mercaptopropionic acid methyl ester, ethylhexyl thioglycolate, thioglycolate, n-butyl thioglycolate, n-octyl thioglycolate, 2-propylheptyl thioglycolate, ethanethiol, 2-propanethiol, butanethiol, isopropanol, n-butyl alcohol, sec-butyl alcohol, acetaldehyde, phosphonic acid or its derivatives, phosphinic acid or its derivatives, iron (III) chloride, silanes and their derivatives, aniline or its derivatives, anthracenes, ethylbenzene, cumene, cyclohexanes, benzene and its derivatives, and naphthalenes.Preferably, 2-mercaptopropionic acid, tert-dodecyl mercaptan, or ethylhexyl thioglycolate is used. Regulators are preferably dosed separately or premixed with reaction components.

[0054] The polymerization for the production of the vinyl acetate-ethylene copolymers preferably takes place in the presence of a protective colloid or in the presence of an emulsifier or, in particular, in the presence of a combination of a protective colloid and an emulsifier.

[0055] Protective colloids commonly used to stabilize the polymerization reaction include, for example, partially or fully saponified polyvinyl alcohols; polyvinylpyrrolidones; polyvinyl acetals; water-soluble polysaccharides such as starches, celluloses, or their derivatives, such as carboxymethyl, methyl, hydroxyethyl, and hydroxypropyl derivatives; proteins such as casein or caseinate, soy protein, and gelatin; lignosulfonates; and synthetic polymers such as poly(meth)acrylic acid and copolymers of (meth) - WP12402 / E

[0056] 13 acrylates with carboxyl-functional comonomer units, polymath) acrylamide, polyvinylsulfonic acids and their water-soluble copolymers; melamine formaldehyde sulfonates, naphthalene formaldehyde sulfonates, styrene maleic acid and vinylethermaleic acid copolymers.

[0057] Preferably, celluloses or their derivatives, or partially saponified polyvinyl alcohols with a degree of hydrolysis of 80 to 95 mol% and a Höppler viscosity of 1 to 40 mPas, in particular 3 to 30 mPas (determination according to DIN 53015, Höppler method, at 20°C, in 4% aqueous solution) are used.

[0058] Particularly preferred are partially saponified, low-viscosity polyvinyl alcohols with a degree of hydrolysis of preferably 80 to 95 mol%, particularly preferably 85 to 90 mol%, most preferably 87 to 89 mol%, and a Höppler viscosity of preferably 1 to 5 mPas and particularly preferably 2 to 4 mPas (determined according to DIN 53015, Höppler method, at 20°C, in 4% aqueous solution).

[0059] Particularly preferred are partially saponified, higher-viscosity polyvinyl alcohols with a degree of hydrolysis of preferably 80 to 95 mol%, particularly preferably 85 to 90 mol%, most preferably 87 to 89 mol%, and a Höppler viscosity of preferably > 5 to 40 mPas, particularly preferably 8 to 40 mPas (determined according to DIN 53015, Höppler method, at 20°C, in 4% aqueous solution).

[0060] If necessary, fully saponified, higher-viscosity polyvinyl alcohols with a degree of hydrolysis of preferably 96 to 100 mol%, particularly 98 to 100 mol%, and a Höppler viscosity of preferably 10 to 56 mPas can also be used (determination according to DIN 53015, Höppler method, at 20°C, in a 4% aqueous solution). WP12402 / E

[0061] 14

[0062] The partially saponified, higher-viscosity polyvinyl alcohols and / or the fully saponified, higher-viscosity polyvinyl alcohols are each used in an amount of 0.1 to 4% by weight, based on the total weight of the monomers.

[0063] A mixture of one or more partially saponified, low-viscosity polyvinyl alcohols and one or more higher-viscosity, especially partially saponified, polyvinyl alcohols is most preferred.

[0064] Modified polyvinyl alcohols, hereinafter also referred to as X-PVOH, with a degree of hydrolysis of 80 to 99.9 mol%, preferably 85 to 95 mol%, and a Höppler viscosity in 4% aqueous solution of 1 to 30 mPas (determined according to DIN 53015 at 20°C), are also preferred. Examples include polyvinyl alcohols containing functional groups, such as acetoacetyl groups. Also preferred are polyvinyl alcohols containing ethylene units, so-called E-PVOH, which are known, for example, under the trade name EXCEVAL®. E-PVOH are partially or preferably fully saponified copolymers of vinyl acetate and ethylene. Preferred E-PVOH have an ethylene content of 0.1 to 12 mol%, preferably 1 to 7 mol%, particularly preferably 2 to 6 mol%, and especially 2 to 4 mol%. The mean mass degree of polymerization is 500 to 5000, preferably 2000 to 4500 and particularly preferably 3000 to 4000.The degree of hydrolysis is generally greater than 92 mol%, preferably 94.5 to 99.9 mol% and particularly preferably 98.1 to 99.5 mol%.

[0065] The protective colloids are commercially available and accessible by methods known to those skilled in the art. Mixtures of the aforementioned protective colloids can also be used. Polymerization preferably takes place in the presence of a total of 2 to 10 wt.% protective colloid, particularly preferably a total of 5 to 10 wt.%, in each case based on the total weight of the monomers. WP12402 / E

[0066] 15

[0067] Non-ionic emulsifiers are preferably used to stabilize the dispersion. Ionic, preferably anionic, emulsifiers can also be used. Combinations of non-ionic and anionic emulsifiers are also possible. The amount of emulsifier is preferably 0.1 to 5.0 wt.%, based on the total weight of the monomers.

[0068] Suitable non-ionic emulsifiers include acyl, alkyl, oleyl, and alkylarylethoxylates. These products are commercially available, for example, under the name Genapol. R or Lutensol Ravailable. This includes ethoxylated mono-, di- and tri-alkylphenols, preferably with a degree of ethoxylation of 3 to 50 ethylene oxide units and C4 to Ci2 alkyl groups; as well as ethoxylated fatty alcohols, preferably with a degree of ethoxylation of 3 to 80 ethylene oxide units and Cs to Cae alkyl groups. Suitable non-ionic emulsifiers also include C13 cis-oxo alcohol ethoxylates with a degree of ethoxylation of 3 to 30 ethylene oxide units, Cie-cis fatty alcohol ethoxylates with a degree of ethoxylation of 11 to 80 ethylene oxide units, C10 oxo alcohol ethoxylates with a degree of ethoxylation of 3 to 11 ethylene oxide units, cis-oxo alcohol ethoxylates with a degree of ethoxylation of 3 to 20 ethylene oxide units, polyoxyethylene sorbitan monooleate with 20 ethylene oxide groups, and copolymers of ethylene oxide and propylene oxide with a minimum content of 10 wt.-% ethylene oxide, polyethylene oxide ethers of oleyl alcohol with a degree of ethoxylation of 4 to 20 ethylene oxide units, and the polyethylene oxide ethers of nonylphenol with a degree of ethoxylation of 4 to 20 ethylene oxide units.

[0069] Particularly preferred are Ci2-Ci4 fatty alcohol ethoxylates with a degree of ethoxylation of 3 to 50 ethylene oxide units, especially 10 to 35 ethylene oxide units. WP12402 / E

[0070] 16

[0071] Examples of suitable anionic emulsifiers are sodium, potassium, and ammonium salts of straight-chain aliphatic carboxylic acids with 12 to 20 carbon atoms; sodium hydroxyoctadecanesulfonate; sodium, potassium, and ammonium salts of hydroxy fatty acids with 12 to 20 carbon atoms and their sulfonation and / or acetylation products; sodium, potassium, and ammonium salts of alkyl sulfates, also as triethanolamine salts, and sodium, potassium, and ammonium salts of alkyl sulfonates with 10 to 20 carbon atoms each and of alkylarylsulfonates with 12 to 20 carbon atoms; dimethyldialkylammonium chloride with 8 to 18 carbon atoms in the alkyl group and its sulfonation products; Sodium, potassium and ammonium salts of sulfosuccinic acid esters with aliphatic saturated monohydric alcohols with 4 to 16 C atoms and of sulfosuccinic acid 4-esters with polyethylene glycol ethers of monohydric aliphatic alcohols with 10 to 12 C atoms, in particular their disodium salts;Sodium, potassium and ammonium salts of sulfosuccinic acid 4-ester with polyethylene glycol nonyl phenyl ether, in particular its disodium salt; sodium, potassium and ammonium salts of sulfosuccinic acid bis-cyclohexyl ester, in particular its sodium salt; lignosulfonic acid and its calcium, magnesium, sodium and ammonium salts; resin acids and hydrogenated and dehydrated resin acids and their alkali salts.

[0072] The polymerization is generally carried out to a conversion of > 95 wt.%, preferably to a conversion of 95 to 99 wt.%, of the liquid monomers under polymerization conditions.

[0073] The aqueous dispersions of vinyl acetate-ethylene copolymers obtained in this way have a solids content of preferably 30 to 75 wt.%, particularly preferably 50 to 65 wt.%. Suitable aqueous dispersions of vinyl acetate-ethylene copolymers are also commercially available. For example, the Vinnapas® dispersions from Wacker Chemie AG. WP12402 / E

[0074] 17

[0075] The polymers are preferably used in the form of protective colloid-stabilized and / or emulsifier-stabilized aqueous dispersions.

[0076] The polymers can preferably also be used in the form of protective colloid-stabilized polymer powders that are redispersible in water.

[0077] To convert the polymers into water-redispersible polymer powders, the dispersions can be dried, optionally after the addition of a drying aid, for example by fluidized bed drying, freeze-drying, or spray drying. Preferably, the dispersions are spray-dried. Spray drying can be carried out in conventional spray drying systems, with atomization achieved using single-, double-, or multi-component nozzles or a rotating disc. The outlet temperature is generally selected in the range of 45°C to 120°C, preferably 60°C to 90°C, depending on the system, the temperature of the resin, and the desired degree of dryness. The viscosity of the feedstock to be atomized is adjusted via the solids content to achieve a value of < 500 mPas (Brookfield viscosity at 20 revolutions and 23°C), preferably < 250 mPas. The solids content of the dispersion to be atomized is > 35%, preferably > 40%.

[0078] The drying aid is typically used in a total amount of 0.5 to 30 wt.%, based on the polymeric components of the dispersion. Suitable drying aids include, for example, protective colloids, preferably those mentioned above. Polyvinyl alcohols are particularly preferred, especially those with a Höppler viscosity in a 4% aqueous solution of 1 to 40 mPas, more preferably 4 to 25 mPas, and most preferably 4 to 13 mPas (Höppler method at 20°C, DIN 53015). The total amount of protective colloid is preferably 1 to 30 wt.%, more preferably 3 to 20 wt.%, and most preferably 5 to 10 wt.%, based on WP12402 / E.

[0079] 18 the total weight of the polymeric components of the dispersion, or relative to the total weight of the polymer powders redispersible in water.

[0080] In atomization, an antifoaming agent content of up to 1.5 wt%, based on the base polymer, has often proven advantageous. The powder can be equipped with an antiblocking agent (anti-caking agent), preferably 0.3 to 30 wt% and particularly preferably 0.3 to 15 wt%, based on the total weight of the polymeric components. Antiblocking agents serve, for example, to increase the shelf life of the powders by improving their blocking stability, especially in powders with a low glass transition temperature. Examples of antiblocking agents are calcium or magnesium carbonate, talc, gypsum, silica (e.g., pyrogenic silica, precipitated silica, or hydrophobically modified silica), kaolins (such as metakaolin), or silicates. Preferred antiblocking agents are silicas, silicates, kaolins, and chalks.The antiblocking agents have particle sizes of preferably 150 nm to 40 pm, particularly preferably 200 nm to 5 pm and most preferably 500 nm to 3 pm (determined using the Coulter LS measuring instrument - Tornado Dry Powder System).

[0081] Preferred carpet coating compositions for manufacturing the carpets are based on one or more vinyl acetate-ethylene copolymers according to the invention, optionally one or more fillers, in particular 100 to 1400 wt.% fillers based on the weight of the vinyl acetate-ethylene copolymers according to the invention, water, optionally one or more additives and optionally one or more additives.

[0082] Suitable fillers include, for example, kaolin, talc, fluorspar, fly ash, aluminum trihydrate, and preferably chalk. Alternatively, the carpet coating compositions contain no fillers. WP12402 / E

[0083] 19

[0084] Examples of additives include thickeners, such as polyacrylates or cellulose ethers, or foaming agents. In the case of foam application, foaming agents are preferably added. Thickeners can be added to adjust the target viscosity of the carpet coating compositions. Generally, an amount of 0.1 to 6 wt%, and preferably 1 to 3 wt%, is sufficient, based on the vinyl acetate-ethylene copolymers. Preferably, a Brookfield viscosity of 500 to 10,000 mPas is achieved in this way (measured with a Brookfield RV gauge with spindle 4, 20 rpm, at 25°C). However, thickeners can also be omitted.

[0085] Common additives include dispersants, wetting agents, water repellents or biocides such as formaldehyde depot agents, isothiazolinones, phenols or quaternary ammonium compounds, antistatic agents and flame retardants.

[0086] The solids content of the carpet coating compositions is preferably 70 to 85 wt.%, particularly preferably 75 to 83 wt.%, in each case based on the total weight of the carpet coating compositions. In the absence of additives or admixtures, the carpet coating compositions have a Brookfield RV viscosity of preferably < 7000 mPas, particularly preferably < 4000 mPas (measured with a Brookfield RV gauge with spindle 4, 20 rpm, at 25°C). Additives and / or admixtures can then be added to carpet coating compositions with such viscosities.

[0087] The carpet coating compositions preferably contain 100 to 1400 parts by weight of filler per 100 parts of vinyl acetate-ethylene copolymer. This is also referred to as a filler content of 100% to 1400%. The amount of filler in the formulation can be adjusted depending on the desired coating properties. WP12402 / E

[0088] 20 properties vary. The higher the filler content (fill level), the lower the mechanical properties.

[0089] The carpet coating compositions according to the invention are characterized by high filler compatibility. Thus, carpet coating compositions based, for example, on vinyl acetate-ethylene copolymers, fillers, and water become available, which, at filler levels of 400 wt.% to 1400 wt.% of the vinyl acetate-ethylene copolymers used, and at a solids content of 75 to 85 wt.%, exhibit a Brookfield RV viscosity of preferably < 7000 mPas and particularly preferably < 4000 mPas (measured with a Brookfield RV measuring device with spindle 4, 20 rpm, at 25 °C).

[0090] If the viscosity of a carpet coating composition is higher before the addition of the thickener, the incorporation times for the filler are extended, which is a disadvantage on an industrial scale, and there is a risk of the formation of non-dispersed filler lumps that can destroy the carpet fabric.

[0091] The vinyl acetate-ethylene copolymers can preferably be used in the form of powders redispersible in water and particularly preferably in the form of aqueous dispersions.

[0092] To produce the carpet coating compositions, the vinyl acetate-ethylene copolymers and subsequently fillers can be stirred into water. Alternatively, the vinyl acetate-ethylene copolymers and fillers can be added to water separately but together. Finally, it is also possible to first produce a premix, particularly a dry mix, comprising vinyl acetate-ethylene copolymers, fillers, and optionally additives. Such WP12402 / E

[0093] 21

[0094] Premixes can then be mixed with water to produce carpet coating compositions. Any additives and admixtures can generally be added at any time, preferably before the addition of fillers.

[0095] The production of carpet coating compositions can be carried out in established carpet manufacturing plants using methods that are known per se.

[0096] The manufacture of the carpets can in principle be carried out in a conventional manner using established devices, provided that one or more carpet coating compositions according to the invention are used.

[0097] First, fibers, also known as carpet pile, are inserted, particularly in the form of tufts, for example as loops, into a woven or laid, generally flat backing material. The loops are generally only loosely attached to the backing material (tufted carpet). For the production of needle-felted carpets, the fiber tufts are needled. In woven carpets, the fiber tufts are woven into the backing material.

[0098] The fibers can generally be either synthetic or natural. Synthetic fibers are based, for example, on polypropylene (PP), polyethylene (PE), polyester (such as PET), or polyamide (such as PA6), polyacrylate, or polylactic acid. Natural fibers are based, for example, on jute, wool, or cotton.

[0099] The carrier material is, for example, a fabric based on polypropylene or polyester. WP12402 / E

[0100] 22

[0101] To improve the bonding of the carpet pile to the backing material, one or more carpet coating compositions according to the invention are generally applied to the back of the backing material (precoat), for example as foam or unfoamed.

[0102] For the primer, carpet coating compositions with filler levels of 300% to 1400% are preferably used. Filler levels of 600% to 1000% are particularly preferred for primers for residential applications, and 300% to 600% for commercial applications such as offices, hotels, or ships. Alternatively, the carpet coating compositions for the primer contain no fillers.

[0103] The carpet products obtained in this way can be equipped with an additional backing material (carpet backing, secondary backing) to improve dimensional stability. For example, a fabric made of synthetic fibers such as polypropylene, polyamide, or polyester, or of natural fibers, can be used as the carpet backing. To bond the carpet backing to the carpet obtained after the primer coat, one or more carpet coating compositions according to the invention are preferably applied again (second coat or secondary coating), for example, as foam or unfoamed.

[0104] For the second coat, carpet coating compositions with filler levels of 200% to 600% are preferably used, in particular 275% to 600% for residential applications and 200% to 400% for commercial applications such as offices, hotels, or ships. Alternatively, the carpet coating compositions for the second coat contain no fillers.

[0105] This makes all types of carpets accessible, such as tufted carpets, woven carpets, or needle-felted carpets. The carpets WP12402 / E

[0106] 23 can be in the form of, for example, roll goods or carpet tiles.

[0107] Generally, carpets that have been produced according to the inventive method for manufacturing carpets are fed into the recycling process according to the invention.

[0108] All types of carpets can be recycled, especially carpets that have reached the end of their use cycle and need to be disposed of, but also waste from carpet manufacturing or remnants from laying carpets.

[0109] The recycling process preferably includes primary shredding of the carpets. Primary shredding generally serves to break the carpets down into smaller pieces that are easier to handle and faster to recycle in the subsequent recycling process.

[0110] Primary shredding is usually carried out mechanically. It can be performed in a conventional manner using conventional shredding equipment, such as shredders; cutting devices like rotary cutters or guillotines; chippers like shear shredders; granulators; rotor shredders; or mills. Primary shredding typically yields carpet pieces that are preferably flat, small, and, in particular, of the most uniform size possible.

[0111] Preferably, the carpets are not turned into powder or particles. Preferably, the carpets are not ground.

[0112] This is advantageous for the recycling of the recycled fibers.

[0113] The carpets, especially those carpets after primary shredding that are sent for further recycling, have a WP12402 / E

[0114] 24 largest diameters of preferably 0.1 to 20 cm, particularly preferably 0.5 to 10 cm and most preferably 0.8 to 5 cm.

[0115] In the essential step of the recycling process according to the invention, the carpets are subjected to one or more solvent treatments with an organic solvent according to the invention. For this purpose, the carpet, the organic solvent, and optionally additives such as emulsifiers are placed in a container. The solvent treatment can take place in any type of container, such as a stirred tank, which is preferably equipped with an agitator, for example, an anchor or propeller agitator, or other common agitators, in particular anchor agitators.

[0116] The proportion of carpet, based on the total weight of the organic solvent, is preferably > 5 wt.%, more preferably > 10 wt.%, particularly preferably > 20 wt.%, and most preferably > 30 wt.%. Higher proportions of carpet are desirable in principle. Surprisingly, the process according to the invention can also be used with higher solids loads in the solvent treatment.

[0117] The solvent treatment is preferably carried out below the boiling point of the organic solvent, particularly at ambient temperature (room temperature), such as 20°C. More preferred temperatures are 10°C to 80°C, particularly preferably 15°C to 60°C, and most preferably 20°C to 40°C. Ambient temperature is most preferred.

[0118] The solvent treatment is preferably carried out at ambient pressure, i.e. 1 atm, in particular 1 bar.

[0119] The solvent treatment is carried out for preferably 10 minutes to 12 hours, more preferably 15 minutes to 6 hours, especially WP12402 / E

[0120] 25 of them preferred 20 minutes to 2 hours and most preferred 25 minutes to 1 hour.

[0121] During solvent treatment, the integrity of the carpet is generally completely or partially destroyed. The carpet's structure, comprised of its various components such as fibers or fiber tufts, primary backing, optionally secondary backing, and the components of the carpet coating composition, is thus generally disintegrated or dissolved, in particular at least partially and preferably completely. The solvent treatment preferably results in a suspension of fibers or fiber tufts, primary backing, components of the carpet coating composition, and optionally secondary backing in an organic solvent.

[0122] The individual components of the slurry from the solvent treatment can be isolated, for example by sieving and drying and possibly further steps, and then recycled.

[0123] For example, the slurry from the solvent treatment can be separated by sieving into a coarse fraction comprising fibers or fiber tufts, primary backing, and optionally secondary backing, as well as a liquid phase containing components of the carpet coating composition and organic solvent. For this purpose, sieves with a mesh size of preferably 100 pm to 1000 mm, particularly preferably 200 pm to 750 pm, most preferably 300 pm to 600 pm, and most preferably 500 pm are suitable.

[0124] Fibers or fiber tufts and backing material (primary backing) and any carpet backing (secondary backing) can be WP12402 / E

[0125] 26. The fibers or fiber tufts can be jointly subjected to further recycling steps, especially if these are based on the same materials or are recyclable as a mixture. Otherwise, fibers or fiber tufts can be separated from the carrier material (primary backing) and any carpet backing (secondary backing) in a conventional manner, as is known to those skilled in the art.

[0126] The fibers or fiber tufts recovered from the carpets are generally suitable for various reuses, for example, for direct recycling, such as for the manufacture of carpets. Preferably, the fibers recovered from the carpets according to the invention, optionally together with the backing material and any carpet backing, are melted, granulated, and recycled, for example, for the manufacture of garden furniture.

[0127] If higher purity fibers are required, particularly for the removal of any carpet additives such as dyes or flame retardants, the fibers recovered from the carpets can undergo further cleaning steps. For example, they can be washed with water and then dried, subsequently melted and, if necessary, granulated and then recycled, generally in common plastic applications. Alternatively, after the aforementioned further cleaning steps, the fibers can be subjected to a chemical recycling process, such as depolymerization. Depolymerization allows the monomers on which the fibers are based to be recovered and then generally recycled in a wide variety of applications, for example, in the production of fibers. In this way, the raw material cycle can be closed in an exemplary manner.

[0128] Alternatively, the fibers recovered from the carpets according to the invention can optionally be combined with the carrier material and any carpet backing, for example in a WP12402 / E

[0129] 27

[0130] Solvents are dissolved, purified, isolated, and subsequently melted and optionally granulated, and then recycled, generally in common plastics applications. Terpenes, for example, are suitable as solvents for dissolving the fibers. Purification can be carried out, for example, by extraction, and isolation by subsequent removal of the solvent. Preferably, purification and isolation are carried out by precipitation and subsequent separation and optional drying of the fiber material.

[0131] The process according to the invention also allows for the recycling, optionally after further purification, of the liquid phase containing components of the carpet coating composition in organic solvent, which was separated from the coarse fraction comprising fibers or fiber tufts, carrier material (primary backing), and optionally carpet backing (secondary backing) by sieving the slurry from the solvent treatment. For example, any fillers in the carpet coating composition can be sedimented by centrifugation, for example at speeds of 500 to 15,000 rpm (revolutions per minute), and isolated by decanting the supernatant slurry, optionally washed, and, after drying and optional grinding, optionally reused as fillers for carpet coating composition in carpet manufacturing.The organic solvent can be removed from the decanted slurry by distillation and reused, for example, for the solvent treatment according to the invention in the recycling process according to the invention or for other purposes. The residue from the distillation of the decanted slurry contains, in particular, the vinyl acetate-ethylene copolymers from the carpet coating composition and can, for example, be thermally recycled. Alternatively, the distillation residue can be granulated and then reused as a filler. Finally, the residue can also be used in WP12402 / E.

[0132] 28 an aqueous emulsion can be converted to obtain vinyl acetate-ethylene copolymers in the form of aqueous dispersions, which can be used, for example, as binders for a wide variety of applications.

[0133] Further processing, in particular separation and any purification, of the slurry obtained by solvent treatment according to the invention can in principle be carried out according to established process steps familiar to the person skilled in the art and using conventional devices.

[0134] Surprisingly, the inventive method allows the fibers (tufts) of the carpets to be recovered efficiently and under mild conditions by recycling them using the inventive solvent treatment, achieving a purity that makes them ideally suited for reuse, generally in common plastic applications. The solvent treatment can be carried out at mild temperatures, particularly below the boiling point of the organic solvents and preferably at ambient temperature. Therefore, organic solvents that are either safe or very easy to handle are also very suitable.

[0135] It is even possible that the carpet fiber (tuft) can be obtained in such purity solely through the solvent treatment of the carpets according to the invention that, after isolation by means of exclusively mechanical processes, such as sieving and drying, and optionally further processing, such as granulation or melt spinning, it can be directly recycled without any further cleaning steps being carried out.

[0136] In light of the many carpet recycling processes already known in the art, it was particularly surprising that the effects according to the invention were achieved even when the carpet fibers were damaged during the inventive WP12402 / E process.

[0137] 29

[0138] The polymers of the carpet coating composition were not dissolved, or substantially dissolved, during the solvent treatment in the organic solvent. Furthermore, the polymers of the carpet coating composition were not completely dissolved in the organic solvent during the solvent treatment according to the invention. Nevertheless, the recycling process according to the invention makes recycled fibers available in surprisingly high purity and yield.

[0139] The following examples serve to further illustrate the invention:

[0140] Analytical methods:

[0141] large particles:

[0142] Mean particle diameter Dv determined using the measuring instruments Horiba LA 950 or Coulter LS 13320 according to ISO 13320 .

[0143] Fixed salary:

[0144] To determine the solids content, in wt. % based on dispersion, 0.3 g of polymer dispersion was weighed out and dried as a thin film on an aluminum foil for 30 minutes at 110 °C in a circulating air drying oven.

[0145] The drying residue was weighed after cooling in the desiccator over silica gel, and the solids content in wt.%, based on dispersion, was calculated from the residue and the initial weight.

[0146] Solubility of vinyl acetate-ethylene copolymers in organic solvents:

[0147] Determined as specified in the general description.

[0148] Determination of the glass transition temperature Tg:

[0149] The glass transition temperature Tg of the polymers was determined in a known manner using DSC (Dynamic Differential Thermal Analysis, DIN EN ISO 11357-1 / 2) with the dynamic differential calorimeter WP12402 / E

[0150] 30

[0151] DSC1 from Mettler-Toledo was determined in an open crucible at heating rates as specified in the measurement program of the following table.

[0152] The glass transition temperature in the heat flow diagram was determined to be the temperature at the midpoint of the stage (midpoint = half the stage height of the heat flow stage) of the second heating curve.

[0153] Measurements were taken in the temperature range between -70°C and 160°C under a continuous nitrogen flow (50 ml / min) in all partial steps. The temporal resolution was one second. The measuring crucible was perforated before the measurement.

[0154] The measurement program is summarized in tabular form below.

[0155] Step temperature range / duration / ramp

[0156] 1 25°C 5 min

[0157] 2 25 to -70°C -20 K / min

[0158] 3 -70°C 5 min

[0159] 4 -70 to 100°C 10 K / min

[0160] 5 100°C 15 min

[0161] 6 100 to -70°C -20 K / min

[0162] 7 -70°C 5 min

[0163] 8 -70 to 160°C 10 K / min

[0164] 9 160 to -70°C -20 K / min

[0165] 10-70°C 5 min

[0166] 11 -70 to 160°C 10 K / min

[0167] Measurement of the stud pull-out force:

[0168] The pull-out force for the carpet nubs was determined in accordance with ISO 4919 using a pinch test machine at 23°C and 50% relative humidity. The carpet was clamped into the attachment at the bottom of the measuring device, and a needle was threaded into a loop of the carpet. The force required to pull out a WP12402 / E was determined on ten different carpet loops.

[0169] 31

[0170] Pull the loop out of the carpet. The average of the measurement results yielded the dry nub pull-out force.

[0171] The wet stud pull-out force was determined accordingly, with the difference that samples prepared for the determination of the dry stud pull-out force were immersed in water for 10 minutes and then superficially patted dry before further testing, thus removing any excess water.

[0172] The nub pull-out force is a measure of the quality of the nub bonding by the primer and of the wear properties of the carpet surface.

[0173] Measurement of the breaking strength:

[0174] The tear strength was determined analogously to DIN EN ISO 11857 ​​using a pinch tester at 23 °C and 50% relative humidity. Three samples were prepared by cutting strips 5 cm wide and 20 cm long from the respective carpet in the machine direction and manually separating them along the narrow side over a length of 5 cm. Each separated sample was clamped into a pinch tester, and the secondary backing was removed from the carpet at a speed of 300 mm / min. The overall mean value from five samples was determined according to DIN EN ISO 11857 ​​from the mean values ​​of the peak values ​​for each sample within the permissible measuring range. The first 25% of each measurement curve were marked and excluded from the evaluation. The next 50% of the graph was divided into five equal sections, and the respective peak value was determined from each of these sections.The peak values ​​were averaged, and the average values ​​were then averaged to obtain the overall mean. The breaking strength was given in Newtons [N].

[0175] To determine the wet release strength, samples prepared as they were for determining the dry release strength were immersed in water for 10 minutes and then further processed according to WP12402 / E

[0176] 32

[0177] The surface of the test area was patted dry to remove any excess water.

[0178] Production of vinyl acetate-ethylene polymer dispersions

[0179] Dispersion A:

[0180] The following components were placed in a 5-liter pressure reactor purged with nitrogen:

[0181] [Template ]

[0182] 1.05 kg deionized water,

[0183] 348 g of a 20 wt% aqueous solution of a polyvinyl alcohol with a mean degree of hydrolysis of 88 mol% and a Höppler viscosity of 4 mPas (determined according to DIN 53015, at 20°C, in 4% aqueous solution) ,

[0184] 383 g of a 10 wt% aqueous solution of a polyvinyl alcohol with a mean degree of hydrolysis of 88 mol% and a Höppler viscosity of 13 mPas (determined according to DIN 53015, at 20°C, in 4% aqueous solution) ,

[0185] 31.5 g of a 40 wt% aqueous solution of a fatty alcohol ethoxylate with a mean degree of ethoxylation of 30 mol EO units,

[0186] 2.01 kg vinyl acetate,

[0187] 0.5 g of a 10 wt% aqueous ammonium iron sulfate solution.

[0188] The sample was adjusted to a pH of 3.9 using formic acid (98 wt%).

[0189] [ Polymerization]

[0190] While stirring (450 rpm), the receiving vessel was heated to 45°C and ethylene was injected up to a pressure of 30 bar. Upon reaching 45°C and 30 bar, the initiator doses, consisting of a 3.0 wt% aqueous potassium peroxodisulfate solution and a 5.0 wt% aqueous sodium isoascorbate solution (WP12402 / E), were started at rates of 20 g / h and 9 g / h, respectively. Fifteen minutes after the start of the initiator doses, the reactor internal temperature was raised to 75°C. Upon reaching 75°C, ethylene was injected up to a target pressure of 67 bar until a total of 490 g of ethylene had been injected. Two hours after the start of the initiator doses, 277 g of vinyl acetate were injected within one hour.

[0191] [After-reaction]

[0192] After the vinyl acetate doses were completed, the initiator doses were continued for another 60 minutes at 40 g / h and 20 g / h respectively, during which time the pressure dropped to 20 bar.

[0193] [Postpolymerization]

[0194] The mixture was then cooled and transferred to a post-processing reactor, where it was post-polymerized by adding 20 g of tert-butyl hydroperoxide solution (TBHP, 10 wt% in water) and 40 g of sodium isoascorbate solution (Na-i-AsAc, 5.0 wt% in water).

[0195] Properties of the polymer dispersion thus obtained: Solids content: 55.0 wt.%

[0196] Brookfield viscosity: 642 mPas (spindle 2, 20 rpm, 23°C)

[0197] Particle size: Dv 1.3 pm, (Coulter LS 1320) Glass transition temperature Tg: 6.4°C (DSC)

[0198] Dispersion B

[0199] The following components were placed in a 5-liter pressure reactor purged with nitrogen:

[0200] [Template ]

[0201] 1.1 kg deionized water,

[0202] 440 g of a 20 wt% aqueous solution of a polyvinyl alcohol with a mean degree of hydrolysis of 88 mol% and a Höppler viscosity of 4 mPas (determined according to DIN 53015, at 20°C, in a 4% aqueous solution), WP12402 / E

[0203] 34

[0204] 200 g of a 25 wt% aqueous solution of a fatty alcohol ethoxylate with a mean degree of ethoxylation of 30 mol EO units,

[0205] 1.8 kg vinyl acetate,

[0206] 0.05 g ammonium iron sulfate.

[0207] The sample was adjusted to a pH of 4.5 using formic acid (98 wt%).

[0208] [ Polymerization]

[0209] While stirring (450 rpm), the receiving vessel was heated to 35°C and ethylene was injected up to a pressure of 30 bar. Upon reaching 35°C and 30 bar, the initiator doses, consisting of an aqueous 3.0 wt% potassium peroxodisulfate solution and an aqueous 5.0 wt% sodium isoascorbate solution, were started at rates of 20 g / h and 9 g / h, respectively. Fifteen minutes after the start of the initiator doses, the reactor internal temperature was raised to 85°C. Upon reaching 85°C, ethylene was injected up to a target pressure of 60 bar until a total of 405 g of ethylene had been injected. Fifteen minutes after the start of the reaction, 540 g of vinyl acetate were injected over a period of two hours.

[0210] [After-reaction]

[0211] After the vinyl acetate doses were completed, the initiator doses were continued for 60 minutes at rates of 40 g / h and 20 g / h respectively, during which time the pressure dropped to 20 bar. [Postpolymerization]

[0212] The mixture was then cooled and transferred to a post-processing reactor, where it was post-polymerized by adding 20 g of tert-butyl hydroperoxide solution (TBHP, 10 wt% in water) and 40 g of sodium isoascorbate solution (Na-i-AsAc, 5.0 wt% in water).

[0213] Properties of the polymer dispersion thus obtained: Solids content: 62.0 wt.%

[0214] Brookfield viscosity: 1700 mPas (spindle 2, 20 rpm, 23°C)

[0215] Particle size: Dv 1.22 pm, (Coulter LS) WP12402 / E

[0216] 35

[0217] Dispersion C:

[0218] Like dispersion A, but with monomer ratios such that polymers with a glass transition temperature Tg of 16°C were produced.

[0219] Properties of the polymer dispersion thus obtained: Solids content: 55.0 wt.%

[0220] Brookfield viscosity: 475 mPas (spindle 2, 20 rpm, 23°C)

[0221] Particle size: Dv 0.95 pm, (Horiba LA 960-v2)

[0222] Dispersion D:

[0223] Like Dispersion B, but with the difference that the post-polymerization was modified as follows:

[0224] For this purpose, 3 kg of dispersion B, with a solids content of 61.4% and a residual monomer (vinyl acetate) content of 2.9 wt% based on the polymer, were transferred from the polymerization reactor to the post-processing reactor (unpressurized vessel) for post-polymerization at 50°C. Additionally, at 50°C, 18.3 g of triallyl cyanurate (TAG) were added as a crosslinking monomer to the now unpressurized reaction mass over 5 minutes. This corresponds to a mass fraction of 1.0 wt% crosslinking monomer based on the polymer. After the crosslinking monomer was added, 12.8 mL of TBHP (10%) and 12.0 mL of Na-i-AsAc (10%) were added simultaneously over 15 minutes with stirring and post-polymerization continued for a total of 40 minutes. The mixture was then cooled to room temperature.

[0225] Properties of the polymer dispersion thus obtained: Solids content: 62.0 wt.%

[0226] Brookfield viscosity: 1860 mPas (spindle 2, 20 rpm, 23°C)

[0227] Particle size: Dv 1.26 pm (Coulter LS), glass transition temperature Tg: 6.6°C (DSC)

[0228] Dispersion E:

[0229] Like Dispersion A, but with the difference that the post-polymerization was modified as follows: WP12402 / E

[0230] 36

[0231] For this purpose, 3 kg of dispersion A, with a solids content of 55.0% and a residual monomer (vinyl acetate) content of 3.59 wt% based on the polymer, were transferred from the polymerization reactor to the post-processing reactor (unpressurized vessel) for post-polymerization at 50°C. Additionally, at 50°C, 16.5 g of triallyl cyanurate (TAG) was added as a crosslinking monomer to the now unpressurized reaction mass over 5 minutes. This corresponds to a mass fraction of 1.0 wt% crosslinking monomer based on the polymer. After the crosslinking monomer was added, 12 mL of TBHP (10%) and 6.6 mL of Na-i-AsAc (10%) were added simultaneously over 15 minutes with stirring and post-polymerized for a total of 40 minutes. The mixture was then cooled to room temperature.

[0232] Properties of the polymer dispersion thus obtained: Solids content: 54.6 wt.%

[0233] Brookfield viscosity: 475 mPas (spindle 2, 20 rpm, 23°C)

[0234] Particle size: Dv 0.95 pm, CV 25%, (Horiba LA 960-v2) Glass transition temperature Tg: 6.6°C (DSC)

[0235] Solubility of the copolymers of dispersions A to E in ethyl acetate as an organic solvent

[0236] The solubility of the copolymers of dispersions A to E in ethyl acetate was determined as described in the general description and is given in the following Table 0.

[0237] Table 0: Solubility of the copolymers of dispersions A to E in ethyl acetate: WP12402 / E

[0238] Production of carpet coating compositions

[0239] Formulation 1 (Fl) (Precoat) :

[0240] Using dispersions A to E, a carpet coating composition was prepared according to the following formula: 100 parts by weight of the respective dispersion (solid / solid), 800 parts by weight of chalk (Calcituft 910W, Alpha Calcite)

[0241] (filler) ,

[0242] 1.6 parts by weight dispersant (Mateo DC 35, Mateo), 0.7 parts by weight foaming agent (sodium lauryl sulfate). The values ​​in parts by weight refer to the dry weight of the respective carpet coating composition.

[0243] Additional water was added in such a quantity that carpet coating compositions with a solids content of 69 to 71 wt.% were achieved.

[0244] To produce the carpet coating compositions, water and the respective dispersion or dispersion mixture were placed in the mixture, and the filler and then the foaming agent were added while stirring.

[0245] Subsequently, a final viscosity of 1000 mPas was achieved by adding a thickening agent (acrylate thickener Mateo TR 10, Mateo) (measured with Brookfield RV measuring device with spindle 4, 20 rpm, at 25°C).

[0246] Formulation 2 (F2) (Secondary Coating): As Fl, but with 300 wt. parts chalk (Foamcarb 505W, Alpha Calcite).

[0247] Additional water was added to achieve carpet coating compositions with a solids content of 77 to 83 wt% and a final viscosity of 1000 mPas (measured with a Brookfield RV gauge with spindle 4, 20 rpm, at 25°C). WP12402 / E

[0248] Carpet manufacturing according to the invention

[0249] The respective carpet coating composition described above was foamed for 3 minutes using a foam mixer (Hansa Mixer PICO-MIX XL; company Hansa-Industrie-Mixer), so that foam liter weights of 490 to 510 g / L were achieved.

[0250] As a precoat, 85 to 89 g of the respective composition of foamed carpet coatings, as specified in Table 1, were evenly distributed on a 37 cm x 33 cm tufted carpet (cut pile tufted carpet: 100% polyamide; 650 g / m²). 2 Pile weight; Jade quality 78; Manufacturer: Condor Carpets (Condor group) ).

[0251] Subsequently, 75 to 80 g of the respective F2 composition, as specified in Table 1, was applied as a second coat (secondary coating) to the foamed carpet backing and evenly distributed. A textile backing (polypropylene fabric, Action Back) was then laid on top and worked in twice with a 1.6 kg roller without pressure. It was then oven-dried for 20 minutes at 130°C to achieve a backing density of approximately 500 g / m². 2 to be kept dry for priming and for the second coat.

[0252] Table 1: Carpet binders: WP12402 / E

[0253] 39

[0254] Comparison carpet V-T4:

[0255] Commercial carpet with a styrene-butadiene copolymer as a binder in the primer and backing.

[0256] Carpet recycling (abbreviation: R):

[0257] The respective carpet was first cut into 1 cm x 1 cm pieces, and 50 g of these carpet pieces were placed in a 1 L glass reactor equipped with a blade stirrer and stirred vigorously at 23 °C for 120 min at 100 rpm for solvent treatment with 450 g of the solvent as specified in Table 2.

[0258] The mixture was then separated into two fractions by a sieve (mesh size 500 pm): one fraction containing carpet fiber residues and the second fraction (filtrate) a suspension of the carpet coating compositions in the respective solvent, which comprised binders (in the cases according to the invention, vinyl acetate-ethylene copolymers) and filler (chalk) as well as additives.

[0259] The fraction containing carpet fiber remnants was washed with water and then dried at 110°C until a constant weight was achieved. The mass of extracted fiber material was determined by weighing.

[0260] The second fraction (filtrate) was dried at 110 °C until dry and constant weight was achieved and then weighed again.

[0261] The results of the solvent treatment of the carpets show that, unlike styrene-butadiene binders, vinyl acetate-ethylene binders can be readily extracted from the carpet backing by solvent treatment with ethyl acetate, leading to extensive to complete destruction of the integrity of the carpet composite (Table 2: column H). WP12402 / E

[0262] Surprisingly, in the case of carpets with vinyl acetate-ethylene binders, binders and fillers can be extracted in substantial quantities (at least 20% by mass, based on the mass of carpet used), whereas in carpets with styrene-butadiene binders only small quantities of binder and filler could be extracted (less than 3% by mass).

[0263] Table 2: Solvent treatment (R) of the carpets:

[0264] B: BM: Binder of the respective carpet:

[0265] Copolymer of the respective dispersion B, D, E or styrene-butadiene copolymer (SB) ;

[0266] C: LM: Solvent of solvent treatment;

[0267] EtAc: ethyl acetate; Toi: toluene;

[0268] D: Fiber yield: Mass of extracted fiber material;

[0269] E: Filtrate: isolated amount of binder and fillers in wt.%, based on the carpet used;

[0270] F: recycled mass of binder BM;

[0271] G: Recycling yield of binder: recycled proportion of binder BM, based on the total amount of binder BM in the carpet;

[0272] H: Disintegration result: Assessment of the carpet's condition using a graduated grading system from 1 to 5 after solvent treatment:

[0273] 1 = Carpet completely disintegrated,

[0274] 5 = Carpet completely intact.

[0275] Carpet fibers could be easily and efficiently separated and recovered using the inventive method by sieving the binder-filler suspension.

[0276] In a further separation step, the binder-filler suspension was separated by centrifugation at 5000 rpm during WP12402 / E

[0277] 41

[0278] Separated for 10 minutes. The separated chalk was washed and dried and can be reused in the production of carpet backings.

[0279] The remaining binder-solvent mixture could be processed by distillation, and the solvent could be almost completely recovered and reintroduced into the extraction process.

[0280] Investigation of the influence of the duration of solvent treatment on the recycling result:

[0281] For this purpose, the carpet recycling example R-l described above was repeated, with the difference that the duration of the solvent treatment was carried out according to the information in Table 3.

[0282] After just 30 minutes of solvent treatment, 73% of the compound has already been extracted, compared to the result after 120 minutes of solvent treatment.

[0283] Table 3: Influence of the duration of solvent treatment of the

[0284] Carpets (TI) on recycling yield: a) : Mass yield of extracted coating mass, based on the carpet coating mass used (dry); b) : Mass yield of binder, based on the total mass of binder in the coating; c) : n . b . : not determined . WP12402 / E

[0285] 42

[0286] Investigation of the influence of temperature on the recycling result during solvent treatment:

[0287] For this purpose, the carpet recycling example R-l described above was repeated with carpet TI, with the differences that the carpet cutouts had formats of 2 x 2 cm and the solvent treatment was carried out at a temperature for a duration according to the information in Table 4.

[0288] The results of the solvent treatment are summarized in Table 4.

[0289] Table 4: Influence of the temperature of the solvent treatment of the carpets TI on the recycling yield: a) : Mass of coating mass extracted from the carpet; b) : Mass yield of extracted coating mass, based on the coating mass in the carpet (dry); c) : Mass yield of binder, based on the total mass of binder in the coating; d) : n . b . : not determined .

[0290] The recovery rate is defined as the ratio of the total dried mass of the fabric after extraction and extract to the mass of the carpet used, expressed as a percentage. The recovery rate is > 99% in all cases.

[0291] The purity of the extracted fabric is defined by the ratio of the mass of uncoated raw fabric (BW) to the extracted and dried fabric mass, expressed as a percentage. With complete extraction of binder and fillers, the purity approaches 100%. WP12402 / E

[0292] 43

[0293] The purity of the recovered tissues obtained through high-temperature extraction ranges from 52% to 56%. Surprisingly, the extraction results are significantly better at lower temperatures of 23°C.

[0294] Investigation of the influence of the solubility of the binders in the solvent of the solvent treatment on the recycling result:

[0295] For this purpose, the carpets described above (see Table 1) were treated according to the carpet recycling process described above, with the differences that the solvent treatment was carried out with ethyl acetate for 60 min at 23 °C, as shown in Table 5.

[0296] The results of the solvent treatment are summarized in Table 5 and show that binders with a solubility content >35% are advantageous for use in carpet backings that are to be recycled using a separation process described here.

[0297] Table 5: Solvent treatment of carpets with ethyl acetate at 23°C for 60 min: a) Solubility of the copolymers in ethyl acetate; the respective dispersion A to E is indicated in parentheses; b) Recycling yield of binder: recycled proportion of binder, based on the total amount of binder in the carpet.

Claims

WP12402 / E 44 Patent claims 1. A method for producing carpets using carpet coating compositions and subsequently recycling these carpets by solvent treatment, characterized in that the carpet coating compositions contain one or more vinyl acetate-ethylene copolymers which have a solubility of 35% to 95% in the organic solvent or mixture of organic solvents used for solvent treatment during the recycling of the carpets, wherein the organic solvents are selected from the group comprising esters, ethers, alcohols, ketones and aliphatic or aromatic hydrocarbons.

2. The method according to claim 1, characterized in that the organic solvents are selected from the group comprising alcohols containing 1 to 7 carbon atoms, esters of carboxylic acids with 2 to 6 carbon atoms and alkyl alcohols with 1 to 6 carbon atoms, ethers containing 2 to 10 carbon atoms, ketones containing 3 to 7 carbon atoms, aliphatic or aromatic hydrocarbons containing 5 to 10 carbon atoms.

3. Method according to claim 1 or 2, characterized in that the organic solvents are selected from the group comprising ethyl acetate, tetrahydrofuran, methyl ethyl ketone and butyl acetate.

4. Method according to claims 1 to 3, characterized in that the vinyl acetate-ethylene copolymers are obtainable by means of radically initiated emulsion polymerization in aqueous medium of vinyl acetate, ethylene and optionally one or more further comonomers. WP12402 / E 45 5. Method according to claims 1 to 4, characterized in that the vinyl acetate-ethylene copolymers are based on vinyl acetate to 60 to 98 wt.%, ethylene to 2 to 30 wt.% and optionally on up to 10 wt.% further comonomers, wherein the values ​​in wt.% refer to the total weight of the monomers and add up to 100 wt.%.

6. Method according to claims 1 to 5, characterized in that the carpet coating compositions are based on one or more vinyl acetate-ethylene copolymers, water, optionally one or more fillers, optionally one or more additives and optionally one or more additives.

7. Method according to claim 6, characterized in that the vinyl acetate-ethylene copolymers are used in the form of colloid- and emulsifier-stabilized aqueous dispersions.

8. Method according to claims 1 to 7, characterized in that the carpets contain fibers based on materials selected from the group comprising polypropylene, polyethylene, polyester, polyamide, polyacrylate, polymethacrylate, polylactic acid, jute, wool and cotton.

9. Method according to claims 1 to 8, characterized in that, during recycling for solvent treatment, the carpets and the organic solvent or the mixture of organic solvents and optionally additives are placed in a container equipped with a stirrer and then the solvent treatment takes place for 10 minutes to 12 hours at temperatures of 10°C to 80°C. WP12402 / E 46 10. A method according to claims 1 to 9, characterized in that the solvent treatment is carried out at ambient temperature.

11. A method according to claims 1 to 10, characterized in that, during the solvent treatment, the integrity of the carpet is destroyed and a slurry of fibers or fiber tufts, carrier material, components of the carpet coating composition and optionally carpet backing in organic solvent is obtained, and one or more components are isolated from the slurry thus obtained by sieving and drying and optionally further steps and are sent for further recycling.

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