Composite material for combining rubber crumb with the ingredients of the rubber mixtures

 

The invention relates to the qualitative and quantitative composition of composite materials for the combination of crumb rubber, which is obtained by grinding waste rubber with other ingredients such rubber mixtures, which are intended for forming of new rubber products. Composite material for combining rubber crumb with ingredients of the rubber compound contains at least one suitable for vulcanization koutsokoumnis ingredient and at least one suitable for the vulcanization of low molecular weight additive. Koutsokoumnis ingredient is at least one liquid at room temperature oligopolies, which is selected from the group consisting of oligospermia butadiene and Acrylonitrile, and epoxidizing of oligospermia butadiene and piperylene. Low molecular weight additive is at least one ester selected from the group consisting of three(oksietilenom)-,-dimethacrylate, trimethacrylate triethanolamine,,-dimethacrylate(bisaillion)phthalate,,-dimethacrylate(bisdithiocarbamate and oligoamenorrhea, which is obtained by the interaction baharoglu esters of bisphenols and 2-phenylenediacrylate. The ingredients of the composite material is taken in the ratio, wt.%: oligopolies 15-50, ester 50-85. Composite material allows you to extend the consumption of surface-activated rubber crumb in the production of heavy rubber products with the most stringent current requirements for sanitary and environmental safety and to increase the proportion of crumbs in the mass of such products in excess of 50%. 4 C.p. f-crystals, 2 tab.

The invention relates to the qualitative and quantitative composition of composite materials for the combination of crumb rubber, which is obtained by grinding waste rubber with other ingredients such rubber mixtures, which are intended for forming of new rubber products.

The problem of disposal of worn-out rubber products and receive from waste rubber new products for industrial and domestic purposes is felt the more, the more economically developed a country and the less its territory.

So, it is well known that pneumatic tires of the wheels of the vehicles are adimov. Annually in the USA alone are worn about 250 million tires, and their total number in the landfills this country exceeds 3109.

Add to that the waste rubber derived from conveyor belts, hoses, shells, inflatable buildings, industrial masks, etc.

Usually tires of such waste is isolated in the form of rubber granules with a particle size preferably less than 2 mm This guy is depending on appointment of new rubber products - can be used either as the basis for, or substantial additive in rubber compounds for their manufacture.

Professionals it is clear that the surface of the particles such crumbs before introduction into the rubber compound must be activated.

In the simplest case, the tool can serve as a partial thermo-mechanical destruction of the old rubber in combination with minimal chemical processing chips for subsequent combining with other ingredients of the rubber mixtures.

So, from EN 97104195/04 A1 is known a method of obtaining a rubber compound, including the production of rubber crumb grinding removed from waste tires vulcanized rubber Serkalem machine, or crushing rolls, a selection of small rubber cross the Oh crumbs in the ratio of 100/50 in the mixer together with the technical carbon, activators, antioxidants, plasticizers, vulcanization accelerators and sulfur, the mixture of these ingredients within 120-180 with at 150-165oWith the pressure to get "fresh" rubber compound.

In the famous invention of the main accent is put on the conditions of mechanochemical processing of rubber crumb, and the composition of plasticizers and activators is itself understood by specialists and not disclosed. However, it is easy to see that the mechano-chemical activation of the surface, which is achieved at the time of receipt crumbs, completely lost because of the "clearing" of the active centers of the oxygen already in the dressing. Therefore, a modified crumb rubber obtained in the described manner, may serve only as a passive filler fresh rubber.

For the conversion of rubber crumb in the active ingredient in rubber compounds is applicable to the method of obtaining regenerate from RU 97102229/04 A1. It includes obtaining rubber crumb destruction grinding of tyres at high pressure, in which the rubber becomes fluidity, a mixture of rosin, bitumen and actuators with rubber crumb in the mixer for dry ingredients at a temperature of 2510oC DM on regenerative mixing or mixing listvennyh rollers at a temperature of 30-60oC.

In this way the rubber crumb is only raw material for rubber reclaim, which is still served and continues to serve as a binder to produce a mechanically fragile waterproofing (in particular, roofing materials and relatively small (usually less than 30%) additive in fresh rubber mixtures, which are used, for example, for the manufacture of reinforced conveyor belts.

If we consider that the overall supply of crumb rubber in the world market increasingly outstrips the demand, it becomes clear the need for such resources activate the surface of the rubber particles to combine with other ingredients in rubber mixtures, which will allow you to minimize the consumption of fresh rubber.

Amid the abundance of inventions aimed at achieving the desired minimum, it may seem that the problem of effective activation of the surface of the rubber crumb is easily solvable. So, in EN 2061710 C1 is proposed to use as a plasticizer in rubber crumb mix the oil with the solvent, which is selected from the group including kerosene, xylene and white spirit, and as an activator of the tetrachloride of tin and/or its hydrated with the addition of from 2.4 to 4.2% calcium oxide by weight of processing akami fresh rubber is not needed.

However, the oil included in the composition of the plasticizer remains in the composition of the products and, as is clear to experts, is not conducive to either increase their durability or ease of handling. Therefore, the use of combination of crumb rubber with other ingredients of the rubber mixtures are applicable only when making non-critical rubber products type of waterproofing materials.

One of the ways to overcome these shortcomings is based on the use of phenol-formaldehyde Novolac resins, which are modified-caprolactam and/or oligomer-lactam concentrate, as a means of combining rubber crumb with other ingredients of the composite materials for the manufacture of elastic products. For curing mixtures using either complex hexachlor-para-xylene with hexamethylenetetramine at a molar ratio of 1:2 (EN 2118969 C1), or hexamethylenetetramine and silicate filler, modified 10-30 wt.% hexachlor-para-xylene (EN 94022311/04 A1).

However, in both cases, the rubber crumb is just filler elastic materials such elastic reinforced products, as V-belts. Therefore, the problem of mass utilization of rubber modification crumbs, which is obtained by crushing the rubber on the basis of an arbitrary chain of rubber, its processing in the medium of organic solvent for 5-7 hours 2-mercaptobenzthiazole, grey and
or exotic LCD alloying additive, which is obtained from recycled biomass (EN 2129128 C1),
or ultrafine powder of copper oxide (RU 2129129 C1),
or ultrafine powder of a solid lubricant selected from the group consisting of tungsten diselenide, molybdenum diselenide, tungsten disulfide and molybdenum disulfide (EN 2129130 C1),
followed by drying the crumbs to remove solvent and heat treatment at the temperature of vulcanization within 40-60 minutes

Therefore, suitable "activators-part-time" is usually chosen
any of the chemicals of devulcanization of rubbers by destroying sulfur bridges between the macromolecules of vulcanized rubber,
either fresh (uncured) rubber and other materials that may adhere to the surface of the particles of crumb rubber with the disclosure of the residual double bonds in vulcanized rubber.

An example of a chemical means of devulcanization can serve as a composition known from EP 0690091 A1. the IO-, dipropylamino, disutility and dibenzyldithiocarbamate;
b) 2-mercaptobenzothiazoles or its derivatives such as zinc salt or benzothiadiazole;
C) sulfenamide type N-cyclohexyl-2-benzothiazolesulfenamide and N-tert-butyl-2-benzothiazolesulfenamide,
g) accelerators of vulcanization of rubbers on the basis of nitrogen-containing compounds of the type guanidine, N, N'-diphenylguanidine, di-ortho-tolylguanidine and 4',4'-demimondaine.

Possible and use only one ie of these compounds in combination with the addition of sulfur, namely 2-mercaptobenzthiazole (EN 2129130 C1).

However, surface devulcanization rubber crumb destruction of sulfur bridges does not provide its strong connection in the "monolithic" of the product during processing. Accordingly specified means activated crumb rubber is suitable mainly in the production of low-duty products type insulating mats, cushioning pads in packages, etc.,

Therefore, increasing application in the practice of recycling rubber granules are "fresh" rubbers and their analogues.

For example, in EN 2061711 C1 for the manufacture of new rubber products proposed to use only rubber crumb with the addition of 10-20 is ucuk, taken by itself, is mostly a binder, and not activating agent. So crumbs can get only malatestiana rubber products.

From among the more effective means of activating the surface of particles of vulcanized rubber to offer the closest composite material for combining rubber crumb with the ingredients of the rubber mixtures according to the US 4481335. It represents a binding that contains
at least one koutsokoumnis suitable for vulcanizing ingredient, which is known binder serves as a high-molecular synthetic rubber, for example a copolymer of 1,4-butadiene and styrene or a copolymer of 1,4-butadiene and Acrylonitrile, or 1,2-polybutadiene, and
at least one is also suitable for vulcanization of low molecular weight additive, which is known binder is a liquid monomer with a double bond. This monomer selected from the group consisting of styrene and Acrylonitrile.

Under intensive mixing such material with sulfur and rubber crumb in a suitable mixer at a temperature mainly 60-93oWith possible to obtain a very homogeneous mixture, in which the vulcanized particles crumb covered were, well are vulcanized by heating in a temperature range mainly 134-177oC and under pressures up to 34.5 MPa and allow you to get pretty strong (tensile strength at break of up to 7 MPa) and elastic (elongation at break of up to 140%) rubber products.

Unfortunately, styrene and Acrylonitrile very toxic and volatile even at room temperature. Therefore, their use requires special measures for the protection of labour and the prevention of emissions into the atmosphere. In particular, a binder, i.e. one of the above copolymers and one of these monomers, previously thoroughly mixed with an equal amount of sulfur or a mixture of sulfur with such agents, vulcanization, as N-tert-butyl-2-benzothiazolesulfenamide or tetramethylthiuramdisulphide. Then this mass, usually in an amount of from 6 to 8%, is mixed with a rubber crumb.

But in this case, some amount of the monomer may remain chemically unrelated. Therefore, the storage and processing of activated rubber crumb also require caution.

In addition, when the binder consumption less than 6% by weight of the original rubber crumb firmness and elasticity from the products is markedly reduced.

And finally activated in the I product type of new car tires in an amount of not more than 30% of their total mass.

The basis of the invention is to improve the quality of the composition and ratio of ingredients to create such a composite material for combining rubber crumb with other possible ingredients of the rubber mixtures, which
first, it would provide a safe sanitary-hygienic and environmental aspects of chemical activation of the surface of the rubber crumb and
secondly, was it possible to manufacture high strength rubber products, in which the number of activated crumb significantly exceeded 30 wt. %.

The problem is solved by the fact that in the composite material for combining rubber crumb with the ingredients of the rubber mixtures containing at least one suitable for vulcanization koutsokoumnis ingredient and at least one suitable for the vulcanization of low molecular weight additive according to the invention:
a) koutsokoumnis ingredient is at least one liquid at room temperature oligopolies, which is selected from the group consisting of oligospermia butadiene and Acrylonitrile, and epoxidizing of oligospermia butadiene and piperylene;
b) a low molecular weight additive is at least one SL">-dimethacrylate, trimethacrylate triethanolamine,,-dimethacrylate(usetranslator)phthalate,,-dimethacrylate(Mediterannean)phthalate, oligoamenorrhea that obtained by the interaction baharoglu ethers of glycols and 2-phenylenediacrylate, and oligourethanes that obtained by the interaction baharoglu esters of bisphenols and 2-phenylenediacrylate, and
C) these ingredients are taken in the ratio, wt.%:
Oligopolies - 15-50
Ester - 50-85
Even from this brief description it is seen that
first, all of the above ingredients nelituji and virtually non-toxic and therefore suitable for absolutely safe sanitary-hygienic and environmental aspects of chemical activation of the surface of the rubber crumb and
secondly, depending on the amount of residual double bonds in the vulcanized rubber, from which was made the crumb, possible a very precise choice of these specific ratios oligopolies and esters, which allows to obtain high-strength rubber products with a concentration of activated crumb zaslujena grinding, such elastomeric original rubber as rubber gas masks, the share of oligopolies in the composite material can be close to the specified minimum, and share at least one of the esters is maximized.

Accordingly, when the processing chips, which is obtained by grinding, for example, such an elastic and slightly tensile source of rubber, such as rubber conveyor belts, hoses or cable sheaths, the share of oligopolies will be close to the specified maximum, and the proportion of at least one of the esters are reduced to an absolute minimum.

The first additional difference is that koutsokoumnis ingredient is oligopolies of butadiene and Acrylonitrile, and a low molecular weight additive, such ester as three(oksietilenom)-,-dimethacrylate. These ingredients are the most affordable on the market and are applicable when surface activating crumbs obtained even from such a pretty inert rubber, which was chloroprene rubbers.

A second difference is that koutsokoumnis ingredient is epoxydecane oligopolies butadiene and piperylene and nizkomolekularnah. This composition can effectively be entered in a mixture on the basis of surface activated crumb modifying additive reagents that are capable of interacting with epoxypropane, for example, the additive is already specified trimethacrylate triethanolamine in the form of crude "technical" product, which always present a significant admixture of mono - and dimethacrylate esters of triethanolamine, and/or Supplement additional hardeners type public non-volatile liquid oligo - or polyamines. Thus it is possible to reduce the consumption of vulcanizing agents while maintaining the mechanical properties of the vulcanizates on the basis of surface activated rubber crumb.

The third additional difference is that koutsokoumnis ingredient is oligopolies of butadiene and Acrylonitrile, and a low molecular weight additive, such ester as trimethacrylate triethanolamine.

Fourth difference is that koutsokoumnis ingredient is epoxydecane oligopolies butadiene and piperylene, and low molecular weight additives such ester as trimethacrylate triethanolamine.

Composite materials according to these two differences, almost effectnum ingredients composite material according to the invention and recommendations for their selection for specific cases, surface activated rubber crumb, obtained from different sources;
description of method of manufacture and the specific examples of the compounds of this material that were used for processing rubber crumb;
describe how the combination of crumb rubber with other ingredients of the rubber mixtures and recommendations for the production and processing of such mixtures and
test results of standard samples, which were made only from the surface of the activated rubber crumb.

Full list of ingredients of a composite material according to the invention and their quantitative ratios are given in table 1.

Specific examples of compounds of this material that were used for production of standard samples, and the test results of these samples to determine the tensile strength at break (BPMPa), and elongation at break (, %) and resistance to repeated bending (N, kilocycle) are given in the attached table 2.

All listed in table 1 ingredients separately available on the market and, if necessary, can be synthesized by well-known specialists of ways.

So, suitable for carrying out the invention oleaut emulsion polymerization of butadiene and Acrylonitrile in a few hours at the temperature not exceeding 30oC and the pH at 7-8. Similarly receive and epoxydecane oligopolies butadiene and piperylene.

Three(oksietilenom)-,-dimethacrylate or otherwise dimethacrylate (hydroxy)ethylene glycol TGM-3, trimethacrylate triethanolamine, TMTAA,,-dimethacrylate(usetranslator)phthalate IFG-1,,-dimethacrylate(Mediterannean)phthalate MDF-1, oligourethanes the OUMA-2F and OUMA-4F produces Dzerzhinsky plant of chemical reagents.

Oligopolies butadiene and Acrylonitrile are interchangeable and can be applied to the surface of the activated rubber crumb almost regardless of its source. Epoxydecane oligopolies butadiene and piperylene is desirable to use, as already mentioned, in combination with amines. Finally, approximately equimolar mixture of these kauchukopodobnoe of oligopolies preferred for processing chips obtained from a rubber-based mixtures of different chain rubbers.

Three(oksietilenom)-,-dimethacrylate brand TGM-3 can be used in composite materials for poverty are useful for the same purpose, together with TGM-3 (up to approximately equimolar amount).

Method of making a composite material according to the invention in General may include
dispensing the selected liquid ingredients and
their preliminary mixing to homogenize for subsequent use of the mixture in the processes of surface activated rubber crumb.

However, it is possible (and even preferred) direct injection of pre-measured doses or continuous dosed introduction of all the selected liquid ingredients together with activated rubber crumb in a suitable mixer.

In real composite materials according to the invention and respectively activated in their chips can be introduced in sufficient quantities (usually amounting to no more than 5% above the total mass of material according to the invention) such protivostaritel additives as light and/or heat, and/or depletability, antioxidants, etc., These additives is subject to the conditions of manufacture and use of rubber products from activated rubber crumb can be easily selected by experts from a number of available on the market.

For the experiments on surface activation in the majority of cases (examples 1-13 and 15, table and clay and other mineral particles and drying of worn tires,
mechanical grinding of such tires,
separation from the mass of shredded rubber, metal and textile cord and classification of treated crumb size.

In particular, for the manufacture of test specimens used rubber crumb, which had a particle size of less than 1.5 mm and contained not more than 0.1% impurities of metal cords, no more than 3% impurity textile cords and no more than 1% impurity mineral particles.

Professionals it is clear that the purer the baby, the greater the maximum size may have its particles. It should be noted that in the above mentioned ratios of the concentrations of impurities can be applied rubber crumb with maximum dimensions up to 4.0 mm while maintaining the mechanical properties of the vulcanizates are approximately on the same level.

In example 14 (table 2) used is free from mechanical impurities powder received on Serkalem machine made of elastic rubber, which was made on the basis of chloroprene rubber. The particle size of this little one was also less than 1.5 mm

Vulcanizing agent in the experiments was only sulfur, although experts it is clear that together with her (and in some cases instead of) could be applied such well-known volcanically etc.),
THIOCARBAMATE (demetillo or diethyldithiocarbamate selenium or tellurium, etc.),
alkylphthalimide or alkylenediamine resin and many others.

In particular, to ensure comparability of test results the amount of sulfur per 100 grams of the specified crumbs in most of the examples was 2.0, But it is clear that - depending on the desired elasticity (or stiffness) of the vulcanizate or from the presence of other curing agents, in particular, polyethylenepolyamine (PEPA), as in example 13 of table 2 - consumption of sulfur may be more or less.

As can be seen from table 2, for the manufacture of the samples was applied only crumb, which was surface activated the corresponding composite materials according to the invention without any additives fresh rubber or other known binders. As a vulcanizing agent in examples 1-12 and 14, 15 used only sulfur as in example 13 - sulfur additive of polyethylenepolyamine.

The rubber crumb was treated composite materials and curing agents according to table 2 at room temperature in the vortex horizontal continuous mixer model AMS-1000, which made Nauchnoye
the case with Windows inlet mix ingredients and production mix,
the mixing chamber, which is located inside
the nozzles for the continuous feed of the mixed ingredients into the mixing chamber, which are located on the one end side of the case,
a tangential inlet for the continuous production of a mixture, which is located on the other end side of the case,
the rotor, which is located inside the mixing chamber and has a
a shaft connected to the rotational drive,
- at least two partitions in the form of discs, which are mounted on the shaft with radial clearance relative to the housing, divide the mixing chamber into sections, and have an overflow box,
- main radial mixing blades which with hub and longitudinal rails mounted on the shaft in the intervals between the said partitions and provided with an additional radial mixing blades, and
- pit radial vanes attached to the shaft in the zone of the outlet ports.

All the ingredients, that is, rubber crumb and selected in accordance with a specific example oligopolies(s), ester (esters) and curing agent was applied to the mixing chamber of the specified mixer continuously and odnosima, the superficiality which is activated in this way can be stored at room temperature for at least 6 months, that is long enough so that it can be transported to other companies for processing into the desired rubber product.

From each mixture according to table 2 vulcanized for 15 minutes at a pressure of 5 MPa and a temperature of 155-165oWere made to the standard samples in the amount of 3x5 pieces to determine the mechanical properties of the vulcanizates, namely:
samples in the form of blades according to GOST 279-75 (ISO 37) - to determine the tensile strength at break and to determine the relative elongation at break, and
samples in the form of plates length 60 mm, width 10 mm and thickness of 3 mm according to GOST 422-75 - to determine the resistance to repeated bending.

Tensile strength and elongation of the samples at break was determined on a standard tensile testing machine at a loading rate of 50050 mm/min, and elongation was calculated as the ratio of the length of each sample at the time of the gap to its original length, multiplied by 100%.

Average arithmetic values of these parameters calculated for each party Obraztsova surface activated rubber crumb in the production of heavy rubber products with the most stringent current requirements for sanitary and environmental safety and to increase the proportion of crumbs in the mass of such products in excess of 50%.

Indeed, even in the manufacture of products not only from the surface of the activated rubber crumb, which is obtained from the protectors worn tires can provide tensile strength at break is not less than 60 MPa, the elongation at break of not lower than 190% and resistance to repeated bending is not below 44 kilocycles, and usually more than 150 kilocycles.

Moreover, the proposed composite material allows you to activate the surface of such inert resins, which are obtained by the use of chloroprene rubber.


Claims

1. Composite material for combining rubber crumb with the ingredients of the rubber mixtures containing at least one suitable for vulcanization koutsokoumnis ingredient and at least one suitable for the vulcanization of low molecular weight additive, characterized in that a) koutsokoumnis ingredient is at least one liquid at room temperature oligopolies, which is selected from the group consisting of oligospermia butadiene and Acrylonitrile, and epoxidizing of oligospermia butadiene and piperylene, b) a low molecular weight additive is at least one ester, which in trimethacrylate triethanolamine,,-dimethacrylate(usetranslator)phthalate,,-dimethacrylate(Mediterannean)phthalate, oligoamenorrhea that obtained by the interaction baharoglu ethers of glycols and 2-phenylenediacrylate and oligourethanes that obtained by the interaction baharoglu esters of bisphenols and 2-phenylenediacrylate, these ingredients are taken in the ratio, by weight. %:
Oligopolies - 15-50
Ester - 50-85
2. Composite material under item 1, characterized in that koutsokoumnis ingredient is oligopolies of butadiene and Acrylonitrile, and a low molecular weight additive, such ester as three(oksietilenom)-,-dimethacrylate.

3. Composite material under item 1, characterized in that koutsokoumnis ingredient is epoxydecane oligopolies butadiene and piperylene, and low molecular weight additives such ester as three(oksietilenom)-,-dimethacrylate.

4. Composite material under item 1, characterized in that koutsokoumnis ingredient is oligopolies butadiene and acrylic is operating material p. 1, wherein koutsokoumnis ingredient is epoxydecane oligopolies butadiene and piperylene, and low molecular weight additives such ester as trimethacrylate triethanolamine.

 

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