DE10035780A1 - Plastics recycling - Google Patents

Abstract

The invention relates to a method for processing used plastic bodies. Said plastic bodies are comminuted and during and/or after the comminution process are treated with an alkaline aqueous solution which contains a) an alkalinity donor and the following other components, at least b) one complexing agent or a complexing agent in the form of a salt chosen from the groups of amino carboxylic acids, phosphonic acids, polycarboxylic acids and/or c) an acid, particularly an acid in the form of a salt chosen from gluconic acid, lactic acid, citric acid, glycolic acid, acetic acid, propionic acid, succinic acid, glutaric acid, adipinic acid, butanedioic acid, fatty acids containing 8 - 18 carbon atoms per molecule, phosphoric acid or mixtures of said acids and/or d) a de-foaming component. The invention also relates to the use of communited plastic bodies obtained according to the inventive method in the production of new plastic bodies, in addition to said plastic bodies which exhibit unique properties.

Description

The invention relates to a method for processing used plastic Bodies as well as the use of ge from the used plastic bodies won plastic materials in the manufacture of new plastic bodies. On The subject matter of the invention is the new ones obtained in this way Plastic body due to its special properties.

For example, we are already producing new plastic bottles Proportioned used plastic material used. The higher the quality of the recycled used plastic material is what for example is visually recognizable by the extent of the color lightening, the higher the percentage that will be used in the manufacture of new plastic bottles can.

For example, it is known from Japanese publication JP 11090934 (273300) that PET bottles are first crushed and then roughly washed with water become. The PET flakes are then ge with organic solvents wash and recycled through further measures.

In Emerging Technologies in Plastic Recycling (ACS Symp. Ser. 513), Washing ton: ACS, 1992, pp. 196-204 describes a process that allows the Manufacture of new PET bottles from 10 to 20% material from used ones Use PET bottles. In this treatment process, the polymer Structure of the PET (from the used PET bottles) broken up, or de polymerized. After going through several process steps, the depolyme Polymerized material together with new PET raw material Siert.  

The above methods are hardly used in practical application. So are used in the processing of plastic bottles, for example PET Bottles (polyethylene terephthalate), the used PET bottles usually perforated and pressed in one process step. With appropriate measures shredded, for example chopped, PET.

In order to achieve the highest possible quality of the resulting granulate, unwanted residues must be removed from and from the shredded PET become.

The residue can be removed, for example, by washing with aqueous Solutions are done. After the washing process, foreign matter may become (Lid, labels, etc.) separated by flotation and / or separators. The ge washed and dried PET is now extruded and granulated.

In flotation, air is pressed or sucked through the wash liquor. there air bubbles combine with the residue particles and / or foreign matter and form a foam on the water surface that removes with fabric scoops becomes.

Usually the washing treatment of the crushed plastic material at alkaline pH values in the presence of alkali hydroxides or other Al potash dispensers and possibly foaming surfactants at temperatures 90 ° C carried out. The washing treatment takes about 20 minutes.

For example, the surfactant-containing product Oakite RC 83 E from FA is already used in processes. Oaktite Europe GmbH, Trakehner Str., Frankfurt / Main dissolved in water in 1-2% concentration and used for washing treatment. The product contains about 40% alkali hydroxide. In addition, the product contains about 19% by weight of C ₉ -C ₁₄ fatty alcohol with about 10 ethoxyl groups and about 11% by weight of the Na salt of C ₈ fatty acid.

The pH of the wash liquor is around 10-11.  

However, the existing process is in terms of the quality of the processed Plastic material, as well as with regard to the process parameters, such as washing time and temperature not yet solved to satisfaction.

For quality reasons, currently only when manufacturing new PET bottles a share of <10% of PET material is used, which comes from the processing used PET bottles.

Accordingly, the present invention set itself the task, the Aufbe improve the riding process of used plastic materials to ver better quality of the processed plastic material and, if necessary, gün more difficult processing conditions.

The present invention relates to a method for processing used plastic bodies, wherein these plastic bodies are crushed during processing and are treated with alkali-aqueous solution during and / or after the crushing process

• a) an alkalinity donor and at least as a further component
• b) a complexing agent or the salt form of a complexing agent is selected from the groups of amino carboxylic acids, phosphonic acids, polymers Carboxylic acids and / or
• c) an acid or the salt form of an acid selected from gluconic acid, Lactic acid, citric acid, glycolic acid, acetic acid, propionic acid, succin acid, glutaric acid, adipic acid, succinic acid, fatty acids with 10 to 18 Carbon atoms per molecule, phosphoric acid or mixtures of them acids and / or
• d) contains a defoaming component.

It is preferred if the alkalinity donor a) in the alkaline aqueous solution based on the total alkaline aqueous solution between 0.01 and 10 wt .-% constitutes and it is particularly preferred if the alkalinity dispenser a) is an alka Iihydroxide is selected from sodium and potassium hydroxide.  

The alkaline aqueous solution preferably has a pH greater than 9.

The proportion of a complexing agent b) in the alkaline aqueous solution based on the total alkaline aqueous solution is preferably between 5 and 40,000 ppm.

In the event that component b) is selected from the group of aminocar bonic acids, preferably nitrilotriacetic acid, ethylenediaminetetraacetic acid right, methylglycinediacetic acid, dicarboxymethyl-L-glutamic acid, serine diacetic acid re, imidosuccinic acid and / or their salts selected.

In the event that component b) is selected from the group of polycarbonates Acids come, for example, from polyacrylic acids and copolymers from maleic acid reanhydride and acrylic acid as well as the sodium salts of these polymer acids in Be costume. Commercial products are e.g. B. Sokalan® CP 5 and PA 30 from BASF, Alcosperse® 175 and 177 from Alco, LMW® 45 N and SPO2 ND from Norsohaas. Suitable native polymers include, for example, oxidized starch (e.g. DE 42 28 786) and polyamino acids such as polyglutamic acid or poly aspartic acid, e.g. B. the companies Cygnus, Bayer, Rohm & Haas, Rhône-Poulenc or SRCHEM.

In the event that component b) is selected from the group of the phosphon acids, for example come 1-hydroxyethane-1,1-diphosphonic acid, diethylene triamine pentamethylene phosphonic acid or ethylenediaminetetramethylene phosphonic acid and their alkali salts in question.

It is preferred if the acid or the salt form of the acid c) is alkaline aqueous solution based on the total alkaline aqueous solution between 5 and makes up 20,000 ppm and it is particularly preferred if the acid c) is selected from gluconic acid, lactic acid, citric acid, fatty acid with 10 to 18 carbon atoms per molecule.  

It is further preferred if the alkaline aqueous solution is defoamed de Component d) one or more surfactants selected from the groups of nonionic surfactants, phosphoric acid esters and their salts and sili contains connections.

The proportion of surfactants d) in the alkaline aqueous solution based on the ge whole alkaline aqueous solution is preferably between 5 and 20,000 ppm.

It is particularly preferred when using a 1% alkaline aqueous NaOH solution which contains about 200 ppm of a defoaming component d), defoaming effect in the Götte test at 20-90 ° C, very particularly preferred is detectable at 50-80 ° C.

In many cases, foam is an undesirable side effect when using Detergents. To avoid cleaning and application technology problems are the foam-forming effects of raw materials and applications test solutions and record them using measurement technology.

The defoamer test is carried out in a foam blow apparatus according to Götte (DIN 53902).

200 ml of the solution to be tested are placed in a 1 L measuring cylinder at 20 ° C, 40 ° C, 50 ° C and 60 ° C. With the help of a perforated disc Foam is created 100 times. The foam height over 200 ml is read immediately after hitting. After that, this process will continue Repeated 4 times, so that a total of 500 blows were carried out. It is in Always carry out double determinations with standards and comparative samples and the mean value is to be formed from the read values.

In addition, dodecylbenzenesulfonate Add triethanolamine salt and try under these tightened conditions repeat conditions. By comparing different alkaline aqueous solutions  can be determined whether the addition of certain components ent produces a foaming effect. If this is the case, then this component can can be described as a component with defoaming properties.

It is also particularly preferred that mixed as nonionic surfactants Ethoxylates / propoxylates of branched or unbranched alkyl alcohols with 8 up to 22 C atoms, very particularly preferably 12 to 22 C atoms, in the alkyl chain available.

It is also preferred that end group closures as nonionic surfactants ne ethoxylates of branched or unbranched alkyl alcohols with 8 to 22 C- Atoms, very particularly preferably 12 to 22 carbon atoms, are present in the alkyl chain gene, wherein the end group closure is preferably a butyl ether or methyl ther lock is.

It is particularly preferred that alkyl polyglucosides with 8 up to 14 carbon atoms in the alkyl group and 1 to 5 glucose units.

Depending on the process and requirements, the alkaline aqueous solution can contain additional Hy contain drotropic or solubilizing agents.

It is further preferred if the additional in the alkaline aqueous solution contained hydrotropes or solubilizing agents are selected from sulfona ten / sulfonic acids and in particular from cumene, xylene, octyl, naphthyl and AL kylbenzenesulfonates / sulfonic acids, in the latter case the alkyl group between 6 and 16 carbon atoms, or mixtures of these compounds and / or other compounds that act as solubilizers.

In a preferred embodiment, the process temperature at which the shredded plastic body is treated with the alkaline aqueous solution, between 40 and 90 ° C, particularly preferably between 60 and 80 ° C.

The duration of treatment of the comminuted plastic bodies is preferably included the alkaline aqueous solution between 1 and 120 minutes, particularly preferred  between 1 and 40 minutes and very particularly preferably between 5 and 15 Minutes.

It is further preferred that the plastic body to be treated at least pro rata from polymers selected from polyethylene terephthalate (PET), polyethylene lennaphthenate (PEN), polycarbonate (PC), polyethylene (PE), polyvinylchloride (PVC), polyamide (PA), polyurethane (PU).

It is preferred to use the method according to the invention for reprocessing disposable or reusable plastic bottles from the food sector.

The process according to the invention is preferably carried out using an alkaline aqueous solution Solution carried out, which additionally at least one peroxidic compound, selected from hydrogen peroxide and / or peracetic acid, perpropionic acid, Persuccinic acid, perglutaric acid, peradipic acid, succinic acid, perfett acids containing 8 to 18 carbon atoms per molecule.

Another preferred embodiment of the method is present in the alkaline aqueous solution additionally contain ester quats.

Quaternized fatty acids are generally referred to as "esterquats" understood retriethanolamine ester salts. These are known substances, which one uses the relevant methods of preparative organic chemistry can get. In this context, the international patent application tion WO 91/01295 (Henkel), according to which triethanolamine in counter were partially esterified by hypophosphorous acid with fatty acids, air passed through and then quaternized with dimethyl sulfate or ethylene oxide. From the Deut The patent DE-C1 43 08 794 (Henkel) is also a process for the manufacture known solid ester quats, in which the quaternization of Trietha nolamine esters in the presence of suitable dispersants, preferably fatty alcohols alcohol, performs.

The quaternized fatty acid triethanolamine ester salts follow the formula (I)

in which R ¹ CO for an acyl radical with 6 to 22 carbon atoms, R ² and R ³ independently of one another for hydrogen or R ¹ CO, R ⁴ for an alkyl radical with 1 to 4 carbon atoms or a (CH ₂ CH ₂ O) _q H -Group, m, n and p in total for 0 or numbers from 1 to 12, q for numbers from 1 to 12 and X for halide, alkyl sulfate or alkyl phosphate. Typical examples of ester quats which can be used in the context of the invention are products based on caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, isostearic acid, stearic acid, oleic acid, elaidic acid, arachic acid, behenic acid and erucic acid and their technical grade Mixtures such as those that occur when natural fats and oils are split. Technical C _12/18 coconut _fatty acids and in particular partially hardened C _16/18 tallow or palm fatty acids and elaidic acid-rich C _16/18 fatty acid cuts are preferably used. The fatty acids and the triethanolamine can be used in a molar ratio of 1.1: 1 to 3: 1 to produce the quaternized esters. With regard to the application properties of the ester quats, a use ratio of 1.2: 1 to 2.2: 1, preferably 1.5: 1 to 1.9: 1 has proven to be particularly advantageous. The preferred ester quats are technical mixtures of mono-, di- and triesters with an average degree of esterification of 1.5 to 1.9 and are derived from technical C _16/18 - tallow or palm fatty acid (iodine number 0 to 40). From an application point of view, quaternized fatty acid triethanolamine ester salts of the formula (I) have proven to be particularly advantageous, in which R ¹ CO for an acyl radical having 16 to 18 carbon atoms, R ² for R ¹ CO, R ³ for hydrogen, R ⁴ for a methyl group, m, n and p are 0 and X is methyl sulfate.

In addition to the quaternized fatty acid triethanolamine ester salts, quaternized ester salts of fatty acids with diethanolalkylamines of the formula (II) may also be used as ester quats,

in which R ¹ CO for an acyl radical having 6 to 22 carbon atoms, R ² for hydrogen or R ¹ CO, R ⁴ and R ⁵ independently of one another for alkyl radicals with 1 to 4 carbon atoms, m and n in total for 0 or numbers of 1 to 12 and X represents halide, alkyl sulfate or alkyl phosphate.

Finally, the quaternized ester salts of fatty acids with 1,2-dihydroxypropyl dialkylamines of the formula (III) should be mentioned as a further group of suitable ester quats,

in the R ¹ CO for an acyl radical having 6 to 22 carbon atoms, R ² for hydrogen or R ¹ CO, R ⁴ , R ⁵ and R ⁷ independently of one another for alkyl radicals with 1 to 4 carbon atoms, m and n in total for 0 or Numbers from 1 to 12 and X stands for halide, alkyl sulfate or alkyl phosphate.

The process according to the invention is preferably carried out using an alkaline aqueous solution carried out in which at least fluorosurfactants are contained as defoamers d).

It is also preferred that in the process according to the invention in one Step alkali hydroxide is dissolved in water and to this alkaline aqueous solution one or more additives, which add one or more of the Components b) to d) contain and particularly preferably in the form of aqueous Solutions, gel, emulsion, paste, dispersion, powder, granules, flakes, pearls, Tablets, block-like shaped bodies, extrudate are present.

In a particularly preferred form contain the ge in the previous paragraph called additives additional tracer substances, such as halides, for example  Potassium iodide, or like fluorescent dyes, as reference substances for the Concentration detection of the active substance present in the alkaline aqueous solution substances by, for example, ion-selective measurement or quantitative measurement the fluorescent portions of the solution.

In the method according to the invention, the surface of the shredded plastic body by dipping and / or using aids such as for example spray device and, if necessary, by mechanical action kung brought into contact with the alkaline aqueous solution.

Another object of the present invention is that the egg crushed plastic body treated in the process according to the invention used in the manufacture of new plastic bodies. Due to the ho hen quality of the shredded plastic body can, for example, at the Manufacture of new PET bottles more than 10%, particularly preferably more than 20% of the PET raw material from the reprocessing according to the invent process according to the invention. The qualitative advantages of using it offers of processed material according to the invention, among others the examples clearly.

Another object of the present invention is plastic Bodies that are processed by recycling plastic Material are available. Depending on the proportion of processing according to the invention material and the individual conditions of the process for processing used plastic bodies, the properties of the new provided plastic body can be set advantageously.

For example, it is common in beverage manufacturing companies that the gewa reusable plastic bottles, for example based on PET, PEN or PC, undergo an automatic inspection for freedom from residues the. In practice, the automatic inspection has the disadvantage that after washing on the inside and / or outside surface of the washed  Plastic reusable bottles can still leave drops of water NEN. Depending on the size of the water drops, this can cause them to fall on due to the sensitivity of the automatic inspection device as a back was detected, and consequently the washed plastic Reusable bottles are ejected. Because of this "incorrect removal" In many companies, plastic reusable bottles are actually disposed of are still in perfect condition. Because the bottle pool for a drink manufacturing company is a very important asset, there is a large one Need, the number of "false rejections" due to on the surface of water droplets left behind from washed plastic reusable bottles to keep as low as possible.

This problem is solved by reusable plastic bottles, in their manufacture position according to the invention processed plastic material is used.

It is preferred if an organofluorine is used in the treatment process Component, particularly preferably an additional fluoroorganic polymer, such as for example polytetrafluoroethylene and / or an organofluorine surfactant was set.

It is also preferred if as a defoamer d) in the preparation process an organofluorine defoamer was used.  

Examples

To arrive at criteria that differentiate the invention To enable teachings from the state of the art, standard Parameters of the test execution determined.

Used 1.5 L PET reusable bottles with labels of the same type (Coca Cola label, stomach and back label) and the same amount (10-18 g / m ² ) of labeling adhesive (synthetic resin glue with casein content) are used as the starting material. A reusable PET bottle weighs about 80 to 100 g. There is an average of about 0.5 g of labeling adhesive and about 1 g of label on a returnable PET bottle.

The PET multi-mreg bottles equipped in this way are produced under identical conditions 20 wash cycles in the same bottle washer with high contaminated alkali (COD <10,000 mg / L).

These PET bottles pretreated in this way are cut into pieces measuring approx. 1 × 1 cm kleinert. About 10 g of the pieces are selected per experiment so that the proportion approximately on labeled PET surface and labeling adhesive per examination is equal to. These PET pieces are in 1000 ml of the invention or Comparative solutions given and at 80 ° C with a commercially available magnetic Laboratory stirrer with a stirring speed of approx. 400 revolutions / min 10 Stirred for minutes.

After the time has elapsed, the PET pieces are removed from the lye using a sieve.

The inventive or the comparative solutions are alkaline aqueous solutions containing 0.5% by weight NaOH and 0.3% by weight of an additive A _v (comparative embodiment according to the prior art) or an additive A _x ( execution according to the invention) included.

The recipes for additive A _v and additive A _x can be found in table 1.

Table 1

Formulations of additives A _v and A _x : proportions in% by weight based on the total additive (remainder to 100% by weight = water)

Ver different criteria that are used in the visual evaluation be weighted (Table 2).  

Table 2

Evaluation criteria and classifications

The experiments according to the invention or the comparison experiments were already carried out in the written manner and then carried out the visual assessment men. The results of the tests are summarized in Table 3.  

Table 3

Test results depending on the additive to 0.5% NaOH solution

As can be seen in Table 3, the use of certain selected additive Combinations, or of alkaline aqueous solutions that contain certain active ingredients contain a number of advantages in the process for processing PET Reusable bottles, which can be found both in the treatment process and in the qua of the processed PET material.

Claims (21)

1. Process for the preparation of used plastic bodies, these plastic bodies being crushed during the treatment and being treated with an alkaline aqueous solution during and / or after the crushing process

• a) an alkalinity donor and at least as a further component
• b) a complexing agent or the salt form of a complexing agent selected from the groups of amino carboxylic acids, phosphonic acids, polymeric carboxylic acids and / or
• c) an acid or the salt form of an acid selected from gluconic acid, lactic acid, citric acid, glycolic acid, acetic acid, propionic acid, succinic acid, glutaric acid, adipic acid, succinic acid, fatty acids with 10 to 18 carbon atoms per molecule, phosphoric acid or from mixtures of these acids and /or
• d) contains a defoaming component.

2. The method according to claim 1, characterized in that as alkalinity donors that in the alkaline aqueous solution, based on the total alkaline aqueous solution, between 0.01 and 10 wt .-% of an alkali hydroxide selects from sodium and potassium hydroxide present. 3. The method according to any one of claims 1 or 2, characterized in that the temperature at which the shredded plastic body with the alkaline treated aqueous solution is between 40 and 90 ° C. 4. The method according to any one of claims 1 to 3, characterized in that the treatment of the shredded plastic body with the alkaline aqueous Solution takes between 1 and 120 minutes. 5. The method according to any one of claims 1 to 4, characterized in that the plastic body is at least partially selected from a polymer  Polyethylene terephthalate (PET), polyethylene naphthenate (PEN), polycarbonate (PC), polyethylene (PE), polyvinyl chloride (PVC), polyamide (PA). 6. The method according to any one of claims 1 to 5, characterized in that the plastic body disposable or reusable plastic bottles for the Le represents the food sector. 7. The method according to any one of claims 1 to 6, characterized in that in the alkaline aqueous solution based on the total alkaline aqueous Solution between 5 and 40,000 ppm of complexing agent b) are present. 8. The method according to any one of claims 1 to 7, characterized in that in the alkaline aqueous solution based on the total alkaline aqueous Solution between 5 and 20,000 ppm of the acid or the salt form of the acid b) available. 9. The method according to any one of claims 1 to 8, characterized in that in the alkaline aqueous solution, based on the total alkaline aqueous solution Solution, as a defoamer d) between 5 and 20,000 ppm of a surfactant Component. 10. The method according to any one of claims 1 to 9, characterized in that in the alkaline aqueous solution additionally contain at least one hydrotrope is. 11. The method according to any one of claims 1 to 10, characterized in that in the alkaline aqueous solution additionally at least one peroxidic Compound selected from hydrogen peroxide and / or peracetic acid, Perpropionic acid, persuccinic acid, perglutaric acid, peradipic acid, pearls contain succinic acid, perfect acids with 8 to 18 carbon atoms per molecule is.   12. The method according to any one of claims 1 to 11, characterized in that Ester quats are additionally contained in the alkaline aqueous solution. 13. The method according to any one of claims 1 to 12, characterized in that in the alkaline aqueous solution as defoaming component d) at least least contains a fluorosurfactant. 14. The method according to any one of claims 1 to 13, characterized in that the alkaline-aqueous solution by dissolving alkali hydroxide and adding is available from one or more additives. 15. The method according to claim 14, characterized in that the or the ad ditives as an aqueous solution, gel, emulsion, paste, dispersion, powder, granulate, Dandruff, beads, tablets, block-like moldings, extrudate are present. 16. The method according to any one of claims 14 or 15, characterized in that that the additive or additives mentioned contain additional tracer substances th. 17. The method according to any one of claims 1 to 16, characterized in that the surface of the crushed plastic body by dipping and / or via aids, such as, for example, spraying device and, if appropriate by mechanical action in contact with the alkaline aqueous solution brought. 18. Use of the shredded treated according to claims 1 to 17 Plastic body in the manufacture of new plastic body. 19. Plastic body made of used plastic body according to one Process according to one of claims 1 to 17 were prepared were.   20. Plastic body according to claim 19, characterized in that in the Preparation process as defoamer d) an organofluorine compound is used. 21. Plastic body according to one of claims 19 or 20, characterized records that in the treatment process according to one of claims 1 to 17 an additional component selected from organofluorine surfactant and fluoroorganic polymer such as polytetrafluoroethylene is added.