WO2021003541A1

WO2021003541A1 - Process of agglomeration by coacervation of vulcanized rubber powder and resulting product

Info

Publication number: WO2021003541A1
Application number: PCT/BR2019/050269
Authority: WO
Inventors: Élyo Caetano GRISON
Original assignee: LEMES, Jorge Antônio
Priority date: 2019-07-11
Filing date: 2019-07-11
Publication date: 2021-01-14
Also published as: BR112022000504A2

Abstract

The invention relates to a process of agglomeration by coacervation of vulcanized rubber powder and the resulting product, comprising a process that arises from the process of manufacturing tire treads and recycling old tires, said process not involving regeneration but aiming to preserve the excellent properties of Camelback as much as possible by using rubber powder of suitable particle size and an agglomerating product with a coacervating polymer additive. The recycling process developed uniformizes the particle size of comminuted rubber (mechanical or cryogenic micronization), preserving the original properties, without chemical or heat treatment, and without generating effluents, fumes or waste. The result is an end product that preserves the quality of scraps and rejects as much as possible.

Description

AGGLOMERATION PROCESS BY VACCANIZED RUBBER POWDER COACERVATION AND RESULTING PRODUCT FIELD OF THE INVENTION

[01] The present invention describes an agglomeration process by coacervation of vulcanized rubber powder and resulting product. More specifically, it comprises a process for recycling scraps or vulcanized rubber scraps resulting from the process of manufacturing tread or recycling old tires, and this process does not regenerate, but seeks to preserve the good properties of camelback to the maximum by using of the rubber powder in a suitable granulometry and through the use of an agglomerating product added by coacervant polymer.

[02] This agglomeration process aims to obtain a product that preserves the properties of the agglomerated material as much as possible, avoiding the use of high temperatures (> 70 ° C), depolymerizing processes or that physically-chemically alter the good quality of the agglomerated material, in order to facilitate handling in the usual processes without the need for process aids to avoid blocking or excessive adhesion to the walls of the equipment used in the production process.

[03] Thus, the recycling process developed standardizes the granulometry of comminuted rubber (mechanical or cryogenic micronization) preserving the original properties without chemical or thermal treatment, without generating effluents, fumes or residues.

[04] Resulting in a final product that preserves the quality of scraps and scraps to the maximum, and can be added to new ones compounds as a highly compatible additive due to the preservation of the characteristics and properties of the camelback.

BACKGROUND OF THE INVENTION

[05] A study by the University of Vrije, in the Netherlands, found that around 2 million new tires are manufactured every day in the world. This means an annual production of 730 million tires (January / l 999). At the same time, today 800 million units are turned into scrap every year.

[06] In Brazil, in 1993, 0.5% of Brazilian urban waste was old and discarded tires. Today, around 17 million tires are discarded in the country each year.

[07] In addition, the treadmill production plants end up generating various residues (scraps, refuse, burrs and others) resulting from the manufacturing process, which are discarded or directed to recycling, generating an environmental liability that is difficult to solve due to material characteristics and the high cost for correct recycling.

[08] The current recycling process and reuse of these materials is usually carried out by separating vulcanized rubber from other components (such as metals and fabrics), so that the materials (tires, scraps and scraps) are cut into chips and classified by a sieve system. The chips are ground and then subjected to autoclave digestion with chemicals, such as: dixylil disulfide and mineral oils, to devulcanize them.

[09] The product obtained can then be refined in mills until obtaining the regenerated, rubber with compromised properties and an unpleasant odor, producing fetid, effluent fumes highly contaminated with a difficult and costly treatment process and residues resulting from this process.

[010] Thus, it is important to note that the regeneration of the material is an outdated process that turns a noble material (camelback) into a poor material, so that depolymerization is evident by the drop of approximately 70% of the original mechanical properties and the devulcanization occurs because the regenerate can be vulcanized again and the strong odor reveals an intense concentration of mecaptans.

[011] Currently, many companies use rubber powder with a 40 mesh granulometry, mixing "in natura" directly into the camelback compound in the act of mixing in the bambury. In this case, the powder acts as a diluent filler.

[012] Some manufacturers use rubber powder additive with asphalt as a binder without worrying about making it compatible, resulting in a poor quality compound. Ordinary asphalt is used to agglomerate dust and this mixture is used as a filler in low quality products: slabs, carpets, additives on pavements, not serving as an additive for camelback.

[013] In research carried out in the state of the art, we identified several processes aimed at the regeneration and recycling of these materials, where we can highlight the following document:

[014] The document IT201 1AN0150 describes a method of producing a compound for making bitumen modified for asphalts is disclosed, comprising the following steps: grinding of vulcanized rubber to obtain vulcanized granulated rubber with a particle size of less than 0.4 mm mixture of said fragmented vulcanized rubber, SBS and lubricant in the extruder, where the percentage by weight of lubricant is comprised between 1% and 50% in comparison with the weight of the mixture and the vulcanized fragmented rubber in percentage by weight of 70-100% in comparison with the weight of SBS in order to obtain an extruded compound containing the said vulcanized fragmented rubber, SBS and lubricant.

[015] This document identified in the state of the art deals with a compound obtained by granulated rubber, SBS and lubricant, aiming at the use of modified asphalt for road paving, but unsuitable for use with the camelback.

[016] The recycling processes by agglomeration are numerous, either by adding rubber powder directly to the compost or by adding resin or plasticizers. What is verified is that in none of them the coacervation is verified and then the product does not always give satisfactory results.

[017] Therefore, the present inventor developed an agglomeration process that uses an asphalt with SBS (binder) and tire rubber powder with a particle size equal to or greater than 24 mesh, obtained cryogenically or mechanically. The rubber powder is treated with the binder cold and without any other product in the ratio of 1 to 3, that is, 1 portion of binder to 3 of rubber powder, so that the resulting product obtained is used as an additive for manufacturing new tires and / or to generate new products. The process is purely mechanical, does not use other products or heating, and does not produce effluents, fumes or waste.

[018] Thus, the object of the present invention is a process of agglomeration by coacervation of vulcanized rubber powder due to the process of manufacturing tread and recycling old tires, this process does not regenerate, but seeks to preserve as much as possible the good properties of the camelback through the use of rubber powder in an appropriate size and through the use of a agglomerating product added with coacervant polymer. This agglomeration process aims to obtain a product that preserves the properties of the agglomerated material as much as possible, avoiding the use of high temperatures (> 70 ° C), depolymerization processes or that physically-chemically alter the good quality of the agglomerated material, in order to facilitate handling in the usual processes without the need for process aids to avoid blocking or excessive adhesion to the walls of the equipment used in the production process.

[019] The recycling process developed standardizes the granulometry of comminuted rubber (mechanical or cryogenic micronization) preserving the original properties without chemical or thermal treatment, without generating effluents, fumes or residues. Resulting in a final product that preserves the quality of scraps and scraps to the maximum, being able to be added to new compounds as a highly compatible additive due to the preservation of the characteristics and properties of the camelback.

SUMMARY OF THE INVENTION

[020] It is characteristic of the present invention a process of agglomeration by coacervation of vulcanized rubber powder and resulting product that provides the use of asphalt added with SBS and tire rubber powder with a granulometry equal to and greater than 24 mesh, obtained cryogenically or mechanically. [021] A characteristic of the present invention is a process of agglomeration by coacervation of vulcanized rubber powder and the resulting product that provides a process is to obtain a recycle that can be added in high dosage without appreciably changing the characteristic properties of the camelback.

[022] It is characteristic of the present invention a process of agglomeration by coacervation of vulcanized rubber powder and resulting product that provides that the compatibilizing mixture is made cold in usual equipment, such as: closed mixer (bambury) or open mixer (cylinder or refiner), where the SBR rubber powder (camelback) is mixed with asphalt added with SBS, in a 1 to 3 ratio of binder in relation to the rubber powder.

[023] A characteristic of the present invention is a process of agglomeration by coacervation of vulcanized rubber powder and the resulting product that provides elastoplastic polymer at rest, showing significant shrinkage or shrinkage that eliminates the air trapped in the core of the agglomerate with which the powder becomes integral. of the cluster.

[024] It is characteristic of the present invention a process of agglomeration by coacervation of vulcanized rubber powder and resulting product that provides a final yield then it is a ratio of 1, 5 of binder to 3 of rubber powder ie 1, 5 of binder for 3 of SBR rubber powder.

[025] A characteristic of the present invention is a process of agglomeration by coacervation of vulcanized rubber powder and the resulting product that provides a mixture of SBR rubber powder with SBS is 100% compatible. [026] A characteristic of the present invention is a process of agglomeration by coacervation of vulcanized rubber powder and resulting product that provides a camelback rubber powder with a particle size of less than 24 mesh which maintains the primary characteristics of the tailings derived from the banding process tire tread or recycling old tires.

[027] A characteristic of the present invention is a process of agglomeration by coacervation of vulcanized rubber powder and the resulting product that provides a final yield, then it is 1.5 kg of binder for 3 kg of camelback rubber powder.

[028] It is characteristic of the present invention a process of agglomeration by coacervation of vulcanized rubber powder and resulting product that provides a process that does not generate effluents, fumes or residues. The compatibility of the agglomerate with the camelback remains high and the properties remain high.

DETAILED DESCRIPTION OF THE INVENTION

[029] The agglomeration process by coacervation of vulcanized rubber powder and the resulting product, the object of the present invention, describes an agglomeration process that uses asphalt with SBS and tire rubber powder with a grain size equal to and greater than 24 mesh, obtained cryogenically or mechanically, which can either be produced in the same plant or purchased from third parties.

[030] The purpose of this process is to obtain a recycle that can be added in high dosage without appreciably changing the characteristic properties of the camelback. [031] Camelback means the vulcanized synthetic rubber compound of SBR (synthetic copolymer of styrene-butadiene emulsion) reinforced with carbon black in sufficient quantity to reach the standard hardness of 63 + - 1 Shore A, measured according to with the ASTM D 2240 standard, using shore A measured durometer. The density of the standard camelback compound is 1.15 g / cm ³ and the tensile strength is 15 + - MPa.

[032] It is essential that the process is standardized so that the product has a guarantee of standard quality, in such a way that recycling is depolluting and makes polluting residues good quality products for reuse.

[033] The process of agglomerating the rubber powder with the binder is carried out in 2 steps:

Step 1 - mixing in cold compatibilizer

[034] The binder used in camelback rubber powder is oxidized asphalt (free from volatiles) and added with SBS polymer (75% styrene - butadiene (25%).

[035] The binder is produced by petrochemical industries at the end of the oil residue, which receives an oxidative treatment to eliminate or chemically modify light fractions. The material is added with a percentage of elastoplastic polymer to improve the physical-chemical properties of the binder. Resulting in a dark, thermoplastic product with high tensile strength, not friable, nor brittle under impact.

[036] The compatibilizing mixture is made cold in usual equipment, such as: closed mixer (bambury) or open mixer (cylinder or refiner), where the SBR rubber powder (camelback) is mixed with asphalt added with SBS, in proportion from 1 to 3 of binder in relation to the rubber powder. The mixing is fast and the material is easily removed, as it does not adhere to the walls of the mixer. The material is left to rest for a few hours (until it cools down) for coacervation reactions to occur.

[037] The elastoplastic polymer at rest shows significant shrinkage or shrinkage that eliminates the air trapped in the core of the agglomerate, with which the powder becomes part of the agglomerate.

[038] This compression makes the solid mechanically more resistant and this characteristic allows to firmly agglomerate previously loose particles.

[039] The particles of vulcanized rubber (SBR rubber powder) are surrounded by the SBS molecules and the product retracts involving the SBR particles (rubber powder) with an asphalt film containing SBS highly compatible with SBR.

Step 2 - Finish cold plate to form

[040] The agglomeration process is completed with the addition of an additional 50% of agglomerate (oxidized asphalt added with SBS polymer). This provides for the formation of a blanket by compression between the cylinders of the open mixer in such a way that the material agglomerates and loosens from the walls of the mixing equipment. The final yield is then a ratio of 1.5 binder to 3 rubber powder ie 1.5 binder to 3 SBR rubber powder.

[041] This material can be cured by adding curing agents or it can be used as an additive in new compositions. Dosing is at the discretion of the formulator who can dose according to the specification of the product to be manufactured.

[042] As can be seen, at no point in the process does any heating or dosage of any foreign chemical occur. [043] The binder used is a special asphalt that is oxidized to eliminate undesirable components and added with a minimum percentage of polymer compatible with the powder used. The rubber powder - SBR is made with an elastomer that contains 25% styrene and 75% butadiene. The polymer added to the asphalt to agglomerate the SBR powder is SBS which contains 25% butadiene and 75% styrene. So the mixture of SBR rubber powder with SBS is 100% compatible.

[044] In order for the mixture of asphalt and the SBR and SBS rubber powder to form stable, it is left at rest during which the coacervation caused by the shrinkage of the mixed products occurs, transforming the compound into compact material (coacervate).

[045] The process does not use high temperature or regenerating substances to prevent the formation of 'mercaptan' responsible for toxic and smelly fumes.

[046] In this way, the agglomeration process uses an agglomerating product added by coacervant polymer. Additive with thermoplastic polymer with high dimensional recovery power to make the product agglomerate and coacervant so that the vulcanized rubber reduced to powder is mechanically fixed and compacted by coacervation which is evident through the formation of laminates.

[047] In summary, the agglomeration process has the following steps:

a) collection and classification of tailings derived from the process of manufacturing tread or recycling old tires;

b) after separation, the material goes to micronization, which can be done mechanically by grinding, grinding or by cryometry, for particles with a particle size smaller than 24 mesh (mesh <24 #);

c) the cryometric micronization is performed at low temperature (<70 ° C) and does not compromise the good quality of the camelback, considering what the ASTM D 2000 standard establishes for the camelback, temperature in the heat resistance test carried out according to ASTM D 573 - 70h at 70 ° C;

d) it results in a camelback rubber powder with a smaller particle size of 24 mesh, which maintains the primary characteristics of the tailings derived from the tire tread manufacturing process or the recycling of old tires;

e) the resulting rubber powder is mixed with the cold binder in usual equipment, such as: closed mixer (bambury) or open mixer (cylinder or refiner);

f) the SBR rubber powder (camelback) is mixed with oxidized asphalt and reinforced with approximately 15% of SBS elastoplastic (styrene - butadiene - styrene) forming the binder that allows to obtain a product of assured quality, as long as the standard dosage is maintained : 3 kg of camelback rubber powder for 1 kg of binder;

g) the material is left to stand for some time until it has cooled down so that the coacervation reactions can occur;

h) the coacervation makes the solid mechanically more resistant and this characteristic allows to firmly agglomerate previously loose particles;

i) the vulcanized rubber particles (SBR rubber powder) are surrounded by the agglomerate molecules and become part of the agglomerate structure; j) the agglomeration process is completed with the addition of an additional 50% agglomerant (oxidized asphalt added with reinforcing SBS polymer);

k) this promotes the formation of a blanket by compression between the cylinders of the open mixer in such a way that the material agglomerates the components together and the product comes off the walls of the mixing equipment;

L) The final yield is then 1.5 Kg of binder for 3 kg of camelback rubber powder;

m) The agglomerated material can be vulcanized simply by adding the curing agents and doing the heat treatment to obtain the cure. The agglomerate can be used as an additive at the discretion of the formulator who can dose according to the specification of the product to be manufactured either as rubber in new compositions of camelback or other uses such as: floors, carpets, casters and the like.

[048] The process does not generate effluents, fumes or waste. The compatibility of the agglomerate with the camelback remains high and the properties remain high.

[049] Therefore, the agglomeration process does not use temperatures above 70 ° C, does not add process aids, regenerating agents or any other product that could compromise the good quality of the material to be agglomerated.

[050] For other materials not compatible with SBS, elastoplastic suitable for each case is added. The recycling thus carried out preserves the quality of the noble material, allowing its reuse one or more times, reducing the environmental liability and providing good financial and ecological advantages, transforming the onus of recycling in work opportunities of great ecological interest as it is clean and highly profitable.

Claims

1. AGGLOMERATION PROCESS BY VULCANIZED RUBBER POWDER COACERVATION characterized by comprising an agglomeration process that uses asphalt added with SBS and tire rubber powder with a grain size equal to and greater than 24 mesh, obtained cryogenically or mechanically, added in high dosage without significantly altering the characteristic properties of the camelback, through the following steps:

b) after separation, the material goes to micronization, which can be done mechanically by knife milling, grinding or by cryometry, for particulates with a smaller particle size of 24 mesh (mesh <24 #);

c) cryometric micronization is carried out at low temperature (<70 ° C) and does not compromise the good quality of the camelback, taking into account what the ASTM D 2000 standard establishes for the camelback, temperature in the heat resistance test carried out according to with ASTM D 573 - 70h at 70 ° C;

e) the resulting rubber powder is mixed with the cold binder in usual equipment, such as: closed mixer (bambury) or open mixer (cylinder or refiner); f) the SBR rubber powder (camelback) is mixed with oxidized asphalt and reinforced with approximately 15% of SBS elastoplastic (styrene - butadiene - styrene) forming the binder that allows to obtain a product of assured quality, as long as the standard dosage is maintained : 3 kg of camelback rubber powder for 1 kg of binder; g) the material is left to stand for some time until it has cooled down so that the coacervation reactions can occur;

i) the vulcanized rubber particles (SBR rubber powder) are surrounded by the agglomerate molecules and become part of the agglomerate structure;

j) the agglomeration process is completed with the addition of an additional 50% agglomerant (oxidized asphalt added with reinforcing SBS polymer);

m) The agglomerated material can be vulcanized simply by adding the curing agents and doing the heat treatment to obtain the cure.

2. POWDER COACERVATION AGGLOMERATION PROCESS

VULCANIZED RUBBER, according to the claim 1, characterized by the fact that the agglomeration process does not use temperatures above 70 ° C, does not add process aids, regenerating agents or any other product that could compromise the good quality of the material to be agglomerated.

3. AGGLOMERATION PROCESS BY VULCANIZED RUBBER POWDER COACERVATION, according to claim 1, characterized by the fact that when the process uses other materials not compatible with SBS, an appropriate elastoplastic is added for each case, the recycling thus preserving the quality of noble material allowing its reuse one or more times reducing the environmental liability.

4. RESULTING PRODUCT characterized by the process resulting in an agglomerated material formed by a ratio of 1.5 agglomerate to 3 rubber powder ie 1.5 kg agglomerate to 3 kg SBR rubber powder, maintaining the properties characteristics of camelback and can be used as an additive for the manufacture of rubber in new compositions of camelback or other uses such as: floors, carpets, casters and the like.