EP0163649A1

EP0163649A1 - Method for producing synthetic material-containing powder

Info

Publication number: EP0163649A1
Application number: EP84900835A
Authority: EP
Inventors: Erich Strommer; Société Anonyme NOVOPHALT
Original assignee: Novophalt SA
Current assignee: Novophalt SA
Priority date: 1983-02-22
Filing date: 1984-02-21
Publication date: 1985-12-11
Also published as: CA1214893A; FI851157A0; ES529899A0; DK478084A; FI851157L; EP0119985A1; ATA60983A; NO844182L; US4617201A; HU195672B; AT383823B; DK478084D0; DD224312A5; HUT38113A; BR8406985A; ES8506779A1; WO1984003294A1; JPS60500624A

Abstract

Procédé de fabrication d'une poudre finement divisée contenant un matériau synthétique thermoplastique, au cours duquel, pour former les particules contenant le matériau synthétique, on introduit le matériau synthétique thermoplastique dans une substance porteuse non-aqueuse qui est liquide dans la zone de température de fusion du matériau synthétique, on le mélange dans la zone de température de fusion avec la substance porteuse et on ajoute à cette masse de la chaux vive moulue avant d'ajouter encore à la masse une boue aqueuse. La réaction qui se produit entre la chaux vive et la boue aqueuse provoque la transformation de la masse en une poudre contenant le matériau synthétique. On utilise en particulier du bitume pour servir de substance porteuse. Cette poudre peut être avantageusement utilisée pour former un liant bitumineux et contenant le matériau synthétique pour des matériaux de construction.Method for manufacturing a finely divided powder containing a thermoplastic synthetic material, during which, to form the particles containing the synthetic material, the thermoplastic synthetic material is introduced into a non-aqueous carrier substance which is liquid in the temperature range of melting of the synthetic material, it is mixed in the melting temperature zone with the carrier substance and ground lime is added to this mass before adding an aqueous slurry to the mass. The reaction which takes place between quicklime and aqueous mud causes the mass to transform into a powder containing the synthetic material. Bitumen is used in particular to serve as a carrier substance. This powder can advantageously be used to form a bituminous binder and containing the synthetic material for building materials.

Description

Process for producing a powder containing plastic

The invention relates to a method for producing a finely divided powder containing thermoplastic material.

The mechanical processing of thermoplastic plastics, which takes the form of pieces, granules, chips, grains and the like. to a powdery plastic material using appropriate comminution machines, such as cutting units, shredders and mills, is complicated and expensive in various respects. As the particle size becomes smaller, the energy to be used for further fragmentation also rises sharply, so that even with a relatively large amount of energy and the use of powerful machines, a very slow progress in reducing the particle size can soon be achieved. All of this is disadvantageous if larger amounts of a finely divided powder are to be produced from a thermoplastic material which is in a much coarser form.

It is an object of the invention to provide a method of the type mentioned at the outset which can be used to produce a powder which contains finely divided thermoplastic material in a relatively simple manner and with little effort, in particular low energy expenditure.

The inventive method of the type mentioned at the outset is characterized in that thermoplastic material is introduced into a non-aqueous carrier substance, in particular bitumen, which is liquid in the melting temperature range of the plastics material, and in this melting temperature range with the carrier substance to form an, at least visually, homogeneous mass is mixed that ground this mass Quicklime is added and distributed in the mass, that an aqueous sludge is then added to the mass and distributed in the mass, and the mass is converted into a plastic-containing powder by the resulting reaction between the quicklime and the aqueous sludge.

By means of the measures provided according to the invention, the above-mentioned objective can be met very well and a powder which contains thermoplastic plastic in a very finely divided form is obtained in a simple manner with a relatively fast process sequence. It can be carried out with little expenditure on equipment and with low expenditure of energy.

In this method, it is advantageous for the introduction of the plastic material into the carrier substance if the carrier substance is heated to a temperature in the range of the plastic material before the plastic material is introduced. In this way, the mixing of the plastic material with the carrier substance can be carried out quickly and easily and the required heating of the plastic material in the melting temperature range can be accomplished in a very short time in this way. It is also readily possible to enter the plastic material into the carrier substance at ambient temperature, which is advantageous in terms of manipulation and makes heating the plastic starting material, which is rather difficult in itself, unnecessary.

For a homogenization of the mass containing the carrier substance and the plastic material that is as simple as possible, it is favorable if the mass ratio of carrier substance to plastic material is selected between 1: 5 and 10: 1. In the interest of a process sequence which is as quick and simple as possible, easy mixing of the quicklime into the mass containing the carrier substance and the plastic material is of great importance and it is advantageous in the sense of a simple and rapid implementation of this process step, provided that that the mass consisting of the carrier substance and the plastic material or the carrier substance before the addition of the plastic material as an oil or organic solvent forming a solution with the carrier substance or the mass, the boiling point of which is 10 to 20 ° C. lower than the decomposition temperature ¬ temperature of the plastic material used, is added.

When using polyethylene as the plastic material and bitumen as the carrier material, it is further advantageous if a mass ratio of oil or solvent to carrier substance with plastic material of approximately 4: 1 is selected.

If the presence of the oil or solvent added in the last-mentioned embodiment of the method according to the invention is compatible with the later use of the powder to be prepared, this oil or solvent can be left in the reaction mass. As a rule, however, it is preferable to remove the oil or solvent from the mass or from the powder containing finely divided plastic, for which thermal expulsion, in particular distillation, is particularly advantageous if an organic solvent has been added Recommended procedure. Such expulsion or distillation can advantageously be carried out using the heat generated during the reaction of the quicklime with the aqueous sludge or the heating of the mass caused thereby; the solvent distilled off is expediently circulated in order to make the process particularly economical. Decalin and tetralin in particular can advantageously be used as solvents in the pulverization of polyethylene.

In view of the good effectiveness of the powder formation reaction and in view of achieving small particle sizes of the powder constituents, it is expedient if a quicklime ground to a grain size of less than 0.1 mm is used in the process according to the invention. In the interest of a rapid powder formation reaction and a good disintegration effect for the plastic particles, it is further advantageous if highly reactive, soft-fired quicklime is used. Furthermore, it is advantageous if the mass ratio of the mass containing the carrier substance and the plastic material and calculated without oil or solvent to quicklime is between 1: 2.5 and 1: 3.5, preferably 1: 2.8 to 1: 3, chosen x ^ ird.

For the manipulation when adding the aqueous sludge and for the behavior of the reactants when adding the aqueous sludge and in the direction of looking at an exact metering of the amount of water provided with the aqueous sludge, the amount of water provided for reaction with the quicklime is ^" ""'^" it is advantageous if the mass is cooled to a temperature of around 100 ° C. before the aqueous sludge is added.

Because the solid of the aqueous sludge remains in the end product of the process, it is generally favorable for the further processing of the end product if an aqueous sludge containing an inorganic material is used as a solid. It is primarily important that the solid of the aqueous sludge containing the reaction water for the reaction with the quicklime has a sufficiently large porosity and that it does not interfere with the later use of the plastic-containing powder; it comes in handy

OMH

<ι? o " For example, in addition to rock flour, fly ash and bleaching earth are also considered as a solid for the aqueous sludge.

A particularly advantageous embodiment of the method according to the invention provides for the use of red mud, which is obtained as a waste product in the production of aluminum, with regard to the aqueous sludge. Such a red mud is available cheaply and is already obtained in the water-saturated state, so that it no longer has to be processed, and also has a relatively high porosity, so that with a relatively small amount of sludge this is necessary for the reaction with the Quicklime required reaction water can be supplied.

For the powder-forming reaction itself, it is advantageous if the amount of sludge used is selected so that the ratio of the mass of the water contained in the sludge to the mass of the quicklime is between 1: 1.8 and 1: 2, preferably 1: 1.9.

For the starting and the course of the powder-forming reaction, it is advantageous if the aqueous sludge, before it is added to the mass containing the plastic material, the carrier substance and the quicklime, to a temperature above 75 ° C., preferably to about 90 ° C, lying temperature is heated.

In order to be able to control as well as possible the timing of the reaction of the water introduced into the mass with the aqueous sludge with the quicklime present in the mass and an early start of this reaction, which indicates the course of the introduction of the aqueous sludge If it could interfere with the reaction mass, if possible switching off, the procedure is advantageously such that the aqueous sludge is first applied to the surface of the mass and distributed over it and then rapidly stirred into the mass. The process according to the invention offers particular advantages for the production of powders which contain polyolefins, in particular polyethylene, as plastic.

With regard to the process sequence, the use of the bitumen preferably provided as the carrier substance in the method according to the invention is very favorable. However, other substances can also be used as carriers, e.g. Hard paraffin, fats and waxes, if the properties of the bitumen, which is also present in the finished powder, would interfere with the later use of the powder.

The method according to the invention for producing a finely divided powder containing thermoplastic material will now be explained further with the aid of examples.

Example A: 10 parts by weight of bitumen were heated in a heatable vessel to a temperature of about 200 ° C. and 20 parts by weight of coarsely divided polyethylene waste were introduced into this melted, thin bituminous bitumen mass, and the resulting mixture was stirred mixed until there was a visually homogeneous mass. In this way, a slightly pasty, bright melt was obtained. This melt was diluted by adding 40 parts by mass of decalin. 84 parts by weight of finely ground quicklime with a particle size of less than 0.1 mm were stirred into the now relatively thin liquid mass obtained in this way. A highly reactive soft brandy quicklime was used. After the quicklime had been stirred into the mass and evenly distributed, the mass was cooled to a temperature of approximately 100 ° C. This mass was then mixed with 100 parts by mass of red mud, which is a waste product from aluminum production and has a water content of approximately 40 to 50% by mass, this red mud was first preheated to 90 ° C., then onto the surface of the carrier substance, the plastic material and the Mass containing quicklime was applied and distributed over the surface and was then mixed with this mass by rapid and intensive stirring. A sudden use of the reaction of the water contained in the red mud with the quicklime present in the mass was achieved. In this reaction, the quicklime was converted to calcium hydroxide with the water of reaction and a fine free-flowing powder was formed from the entire mass by this reaction.

Example B: The procedure was analogous to that in Example A and initially 20 parts by weight of bitumen were heated to about 200 ° C. 50 parts by weight of polyethylene in divided form were introduced into this hot bitumen mass and the mixture was mixed until visually homogeneous. 100 parts by weight of decalin were then added, and 210 parts by weight of quicklime were then stirred in, and the mixture was then cooled to a temperature of about 100.degree. This mass was then mixed with a mixture previously formed from 180 parts by mass of fly ash and 90 parts by mass of water, which was first carefully layered onto the bitumen-plastic-lime mass and then quickly stirred in. In the reaction that followed, a fine, free-flowing powder was formed from the entire mass.

The invention further relates to a method for producing a bituminous bound building material, in particular road building material, which contains a grain-graded aggregate consisting of filler, sand and grit or gravel and a binding agent and its binder with thermoplastic ¬ chemical plastic, in particular a polyolefin, such as polyethylene, is added.

This method according to the invention is characterized in that the plastic in the form of finely divided particles which mixes with an inorganic material corresponding to a filler in particle size or is attached to these particles. are stored, is added, the plastic preferably being added in the form of a powder containing plastic obtained by a process according to the invention as described above.

With this method, the plastic provided for modifying the binder properties of the bitumen can be introduced into the building material in a simple manner without the aid of special devices, and a very effective modification of the binder can be achieved in relation to the amount of plastic used. This procedure according to the invention can also have disadvantages which occur in known techniques for the plastic coating of bitumen used as a binder, such as Demixing phenomena of the pair of materials bitumen-plastic, practically be switched off.

An embodiment of the method according to the invention is particularly advantageous, which is characterized in that the plastic is added in the course of the mixing process in which the aggregate is combined with the bitumen to form the building material. The powder containing the plastic can advantageously be introduced into the mixture consisting of a bituminous binder and the aggregate using the technique which is normally used for adding the so-called filler.

Both in the interest of achieving the most uniform possible distribution of the plastic in the bitumen and in the interest of making good use of the modifiability of the plastic for the bitumen, it is advantageous if it is provided that plastic with a particle size of less than 0.09 mm is used. It is also advantageous for the introduction of polyethylene as plastic into the binder of the bituminous building material if one provides that a ratio of the mass of the plastic to the mass of the inorganic material, with that of the plastic

-. * Material mixed or to which it is attached, is provided from about 1: 7.5.

The method according to the invention for the production of bituminous bound building materials will now be further explained with the aid of further examples.

B e i s p i e l s g r u p p e 2:

To produce bituminous road building materials, rock or sand material with a sieve line standardized for asphalt concrete 0/18 was preheated to approx. 170 to 180 ° C in an asphalt mixer and bitumen B100, which also has a temperature of approx. 170 to 180 ° C had injected into the mixer. Likewise, the mixer was filled with limestone powder as a filler and further also powder containing plastic, which had previously been produced according to Example A or Example B. Several masses intended for use as road building material were produced in succession, which differed from one another in terms of the amount of addition of plastic-containing powder. The amount of the binder, based on the total amount of the building material mass, to which the bitumen B100 and the plastic portion of the plastic-containing powder is to be counted, was kept constant at 5.1 mass for all masses.

Furthermore, the same amount and composition of the aggregate (rock or sand material, filler) were provided for all the masses, and the same (standardly provided) amount of filler was added, the mineral content of the plastic-containing powder also being added to the filler was calculated and the bitumen content of the plastic-containing powder was also taken into account by a corresponding reduction in the bitumen used to form the respective binder.

From the intimate mixing of the aforementioned components Components obtained in the asphalt mixer were produced in a Marshall procedure in accordance with the standard procedure and these were then tested using conventional technology, the tensile strength in the gap and the compression being determined in particular. These tests were carried out at test temperatures of 25 ° C and 40 ° C. The measurement results obtained in this way from a series of materials with a different plastic content in the binder are shown in the diagrams shown in FIGS. 1 and 2. Curves 1a, 1b, 2a and 2b relate to a material which was produced using plastic powder obtained according to Example A, curve 1c relates to a material which was produced using plastic powder obtained according to Example B.

As can be seen from these diagrams, the gap tensile strength shown by curves 1a, 1b and 1c increases progressively with increasing polyethylene content. A correlation calculation carried out showed that the dependence of the tensile strength on the polyethylene content can be described by a growth function (exponential function with positive high number of the type: y = a + be ^cx ).

The behavior at 25 ° C. expressed by curve 1a tends to be the same as in the behavior at 40 ° C. expressed by curves 1b and 1c.

As can be seen from these curves, the compression of the Marshall bodies investigated, represented by curves 2a and 2b, decreases degressively with increasing polyethylene content. The relationship can be described by a falling saturation function (exponential function with negative exponential element and negative high number y = ab.e ~ ^cx ). The relatively flat course of the curves representing the upsetting shows that the upsetting of the Marshall bodies is only influenced to a small extent by the polyethylene content of the binder, which indicates that the deformability the asphalt is not reduced to an undesirable extent by the plastic content and that the plastic does not. ne increases the risk of cracking occurs. Materials which have been produced using plastic powder obtained according to Example B show a corresponding behavior when examining the compression.

The modulus of elasticity which can be calculated from the examinations carried out on the Marshall bodies has a progressively increasing course with increasing polyethylene content and this can be described by an axial function.

B e i s p i e l s gr up p e 3 - comparison tests

The procedure was analogous to example group 2 and, using the same rock or sand material and the same limestone powder as filler, a number of bituminous bound masses which were intended for use as road building material were produced. The proportions of the rock or sand material and the filler were provided in the same way as in example group 2. However, pure bitumen B100 and bitumen B100, which had already been modified by adding polyethylene, were used as binders. In the case of all the mixtures in this example group, the amount of binder was kept constant, analogously to the mixtures in example group 2, with 5.1 mass, based on the total amount of the building material mass produced in each case.

Several plastic modified bitumens with different

Polyethylene contents had previously been produced by intensive homogeneous working through a mixture of bitumen B100 and shredded polyethylene at a temperature of 270.degree. A mass intended for use as road construction material was produced from each of these plastic-modified bitumens and from the pure bitumen B100 together with the aforementioned rock or sand material and the filler, and these masses were again used in accordance with the standard. Marshall body manufactured and tested analogously to example group 2. The measurement results obtained are also shown in the diagrams shown in FIGS. 1 and 2.

Analogous to the road building materials produced according to example group 2, the road building materials produced according to example group 3 for comparison, as can be seen from the curves 3a and 3b showing the split tensile strength of these road building materials, shows an increasing gap tensile strength with increasing polyethylene content, whereby the dependence of the splitting tensile strength on the polyethylene content in the area under consideration can be described by an increasing saturation function. Likewise, the upsetting of the road building materials produced according to example group 3 increases, as from those that represent the upsetting

Curves 4a and 4b can be seen, similar to the compression of the road building materials according to example group 2, slowly with increasing polyethylene content.

From the comparison of the values determined on building materials according to the invention produced according to example group 2 with corresponding values found on building materials manufactured according to example group 3, it follows that up to one applicable to the respective case and determined by the material components (rock (Filler, bitumen, plastic), the plastic content determined, the building materials produced with the powder technology according to the invention have similar characteristics (for example splitting tensile strength) to building materials which were produced with essentially the same overall composition using plastic-modified bitumen. that above this certain plastic content the characteristic values, in particular the tensile strength at break, of the building materials produced by the powder technology according to the invention are far higher than the characteristic values of the building materials produced using plastic-modified bitumen.

Claims

PATENT CLAIMS:

1. A process for the production of a finely divided powder containing thermoplastic, characterized in that thermoplastic material is introduced into a liquid, non-aqueous carrier substance, in particular bitumen, in the melting temperature range of the plastic material and in this melting temperature range with the carrier substance, at least visually, homogeneous mass is mixed, that ground mass of quicklime is added and distributed in the mass, that an aqueous sludge is then added to the mass and distributed in the mass and the mass resulting from the reaction between the quicklime and the aqueous sludge is converted into a plastic-containing powder.

2. The method according to claim 1, characterized in that the carrier substance is heated to a temperature lying in the melting temperature range of the plastics material before the introduction of the plastic material.

3. The method according to claim 1 or 2, characterized in that the plastic material is entered at ambient temperature in the carrier substance.

4. The method according to any one of claims 1 to 3, characterized in that the mass ratio of carrier substance to plastic material is selected between 1: 5 to 10: 1.

5. The method according to any one of claims 1 to 4, characterized in that the mass consisting of the carrier substance and the plastic material or the Träger¬ substance before the addition of the plastic material with the carrier substance or the mass forming a solution oil or organic solvent, whose boiling temperature by 10 to 20 ° C lower than the decomposition temperature of the plastic material used, is added.

6. The method according to claim 5, characterized gekennzeich¬ net that a mass ratio of oil or solvent to bitumen as a carrier substance with polyethylene as Kunststoff¬ material of about 4: 1 is selected.

7. The method according to claim 5 or 6, characterized ge indicates that the oil or solvent is expelled from the mass, in particular distilled off, during and / or after the reaction of the quicklime with the added aqueous sludge.

8. The method according to any one of claims 5 to 7, characterized in that when using polyethylene as the plastic material as the organic solvent decalin or tetralin is used.

9. The method according to any one of claims 1 to 8, characterized in that ground lime is used to a grain size below 0.1 mm.

10. The method according to any one of claims 1 to 9, characterized in that highly reactive soft burned

Quicklime is used.

11. The method according to any one of claims 1 to 10, characterized in that the mass ratio of the mass containing the carrier substance and the plastic material to quicklime, calculated without solvent, between 1: 2.5 and 1: 3.5, preferably 1: 2.8 to 1: 3, is selected.

12. The method according to any one of claims 1 to 11, characterized in that the mass before the addition of the aqueous sludge to a temperature at about 100 ° C temperature is cooled.

13. The method according to any one of claims 1 to 12, characterized gekennteichnet that an aqueous slurry containing inorganic material is used as a solid.

14. The method according to claim 13, characterized gekenn¬ characterized in that red sludge from aluminum production is used as the aqueous sludge.

15. The method according to claim 13, characterized in that fly ash mixed with water is used as the aqueous sludge.

16. The method according to any one of claims 1 to 15, characterized in that the amount of sludge used is selected so that the ratio of the mass of the water contained in the sludge to the mass of quicklime between 1: 1.8 and 1: 2, preferably at 1 : 1.9, lies.

17. The method according to any one of claims 1 to 16, characterized in that the aqueous sludge, before it is added to the mass containing the plastic material, the carrier substance and the quicklime, to a temperature above 75 ° C, preferably at about 90 ° C lying temperature is heated.

18. The method according to any one of claims 1 to 17, characterized in that the aqueous sludge is first applied to the surface of the mass and distributed over it and then rapidly stirred into the mass.

19. The method according to any one of claims 1 to 18, characterized in that a polyolefin is used as the thermoplastic material.

20. The method according to claim 19, thereby Kerrp- records that polyethylene is used.

21. The method according to any one of claims 1 to 20, characterized in that Hartparaf¬ fin is used as the carrier substance.

22. The method according to any one of claims 1 to 20, characterized in that a fat is used as the carrier substance.

23. The method according to any one of claims 1 to 20, characterized in that a wax is used as the carrier substance.

24. A process for the production of a bituminous bound building material, in particular road building material, which contains a granulated aggregate consisting of filler, sand and grit or gravel and a binder and the binder of which is mixed with thermoplastic, in particular a polyolefin, such as polyethylene is characterized in that the plastic is added in the form of finely divided particles which are mixed with an inorganic material corresponding to a filler or attached to these particles, the plastic preferably in the form of a by a process according to one of claims 1 to 23, plastic-containing powder obtained is added.

25. The method according to claim 24, characterized in that the plastic is added in the course of the mixing process in which the aggregate is combined with the bitumen to form the building material.

26. The method according to claim 24 or 25, characterized in that plastic with a particle size of less than 0.09 mm is used.

27. The method according to any one of claims 24 to 26, characterized in that a ratio of the mass of the plastic to the mass of the inorganic material with which the plastic is mixed or to which it is attached, is provided from about 1: 7.5.