RU2448134C1 - Method to prepare rubber modified bitumen - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method includes preparation of a mixture of bitumen, rubber granules and a plasticiser. The mixture composition additionally includes a maleic anhydride. The plasticiser is vegetable oil. Components in the composition are used at the following ratio, wt %: rubber granules - 12.0-15.0; plasticiser - 5.0-20.0; maleic anhydride - 0.3-0.5; bitumen - balance. In process of composition preparation the vegetable oil is placed into a mixer's reservoir and heated up to the temperature of 120°C. Then bitumen is added to it, preferably, in a melted state. After their mixing, rubber granules are added into the mixer. While mixing, the produced mix is heated up to the temperature of 170°C, which is maintained until the end of the composition preparation. The operation of mixture mixing with rubber granules is carried out for at least an hour. Then maleic anhydride is added to the mixture, and operation of produced mix mixing is carried out for another half an hour at least.

EFFECT: method provides for the possibility to produce a rubber modified bitumen with higher values of elasticity maintained under severe climatic conditions under increased mechanical loads.

4 cl, 1 tbl, 7 ex

Description

The invention relates to building materials with a wide range of applications and can be used for road, roofing, insulation, sealing works.

A known method of preparing a bitumen-rubber composition, including the preparation of a mixture containing in wt.%: Bitumen - 70-80, crumb from vulcanized rubber from used car tires - 15-25 and naphthalene fraction of coal tar - 5-10 (see RU No. 2327719, C08L 95/00, C08L 17/00, C08J 3/20, 2008).

The physicomechanical characteristics of the composition obtained by the known method are very high, but a significant drawback is the use of coal tar fractions with a boiling point of more than 200 ° C as a plasticizer during its preparation. This product is extremely harmful to the health of personnel, as it contains toxic substances, especially benzopyrenes.

There is also known a method of preparing a rubber-bitumen composition, including the preparation of a mixture of bitumen, rubber crumb and plasticizer (see RU No. 2178434, C08L 95/00, C08K 5/32, C08K 5/14, C04B 26/26, C08L 17/00, 2002) .

A mixture of a compound or compounds selected from the group of nitrons capable of forming stable radicals and a peroxide compound is additionally introduced into the composition. Rubber is used in the form of distinguishable partially degraded particles and products of its destruction, contained in an amount of not less than 0.5 wt.% Calculated on the rubber before destruction. The rubber particles contain unsaturated bonds in an amount of at least 2% of the total number of bonds. The composition further comprises a mixture of the above nitron and peroxide compounds, taken in a mass ratio of nitrons: peroxide compound from 1: 1 to 10: 1, respectively. The listed components are used in the following amounts: the above mixture of nitrons and peroxide compounds - 1-2 wt.%, The above mixture of rubber and products of its destruction - 5-30 wt.%, Bitumen - up to 100 wt.%.

The individual physicomechanical characteristics of this known bituminous composition are quite high, but the disadvantage of this solution is manifested in an unsatisfactory set of parameters such as softening and brittleness temperatures and elasticity. In particular, if the best indicator of brittleness temperature (-28 ° С) is reached, then an unsatisfactory softening temperature (+ 50 ° С) is achieved, and if the best softening temperature (+ 92 ° С) is reached, then an unsatisfactory temperature of brittleness ( -18 ° C). And in all cases, the elasticity is very low (no more than 35%). Thus, the composition obtained in the framework of the known method cannot effectively work in the composition of coatings in severe climatic conditions (at outdoor temperatures below -30 ° C and above + 30 ° C).

The problem to which the claimed solution is directed is to provide the possibility of obtaining a rubber-bitumen composition with increased values of elasticity, stored in harsh climatic conditions with increased mechanical stress.

The technical result achieved by solving the problem is expressed in providing the possibility of obtaining materials that effectively "work" in harsh climatic conditions (at outdoor temperatures below -30 ° C and above + 30 ° C) with increased mechanical loads in a wide range of building and road structures.

The problem is solved in that the method for preparing the rubber-bitumen composition, including the preparation of a mixture of bitumen, crumb rubber and plasticizer, is characterized in that maleic anhydride is additionally used in the mixture, while vegetable oil is used as a plasticizer, and the above components are used in the composition when the following ratio, wt. %:

Rubber crumb 12.0-15.0 Plasticizer 5.0-20.0 Maleic Anhydride 0.3-0.5 Bitumen rest

in addition, in the process of preparing the rubber-bitumen composition, vegetable oil is placed in the container of the mixer and heated to a temperature of 120 ° C, after which bitumen is introduced into it, preferably in the molten state, and, after mixing, rubber crumb is introduced into the mixer and heated while stirring the resulting mixture to a temperature of 170 ° C, which is maintained until the preparation of the composition is completed, while the mixture is mixed with rubber crumb for at least an hour, then maleic anhydride is introduced into the mixture and the operation sewing the resulting mixture is still not less than half an hour. In addition, they use bitumen grade BND 90/130. In addition, they use rubber crumb of tire waste, fractions up to 1.5 mm, without its additional processing. In addition, use a mixer made with the possibility of heating the mixture to 180 ° C.

A comparative analysis of the features of the claimed solution with the signs of the prototype and analogues indicates the conformity of the claimed solution to the criterion of "novelty."

Signs indicating that the composition “additionally use maleic anhydride” provides the possibility of creating (with rubber devulcanized from crumb rubber) a polymer complex that provides an increase in the softening temperature and elasticity of the composition after it has hardened. In addition, the introduction of maleic anhydride provides an increase in the adhesive ability of the composition with various materials (with fillers, with concrete, with metal).

Signs indicating that “vegetable oil is used as a plasticizer” provide plasticization of bitumen to a level that makes it possible to obtain lower brittle temperatures of the composition and increase the efficiency of devulcanization of rubber crumb of tire waste (material not subjected to additional intermediate processing).

Signs indicating a concentration range of rubber crumb, maleic anhydride, and a plasticizer (vegetable oil) provide concentrations of these components at which a uniform gel is obtained. Moreover, by varying the concentrations of maleic anhydride and plasticizer (for a given value of the concentration of rubber crumb, which varies in a small range - the difference between the maximum and minimum values of about 20%), various values of the softening temperature and brittleness of the composition can be obtained. This makes it possible to quickly adjust the values of viscosity (penetration) and softening and brittleness of the compositions, which is very important for production conditions, since it provides the possibility of high adaptation of the properties of the material of the composition to the conditions of its operation in specific conditions.

In this case, an increase in the content of plasticizer in the composition over the declared range leads to its sweating on the surface of the cured coating or turns it into a gel-like material. The decrease in the content of plasticizer below the stated range does not allow to achieve the necessary viscosity of the composition and the temperature of brittleness.

Signs indicative of a range of maleic anhydride concentrations provide a softening temperature of the composition at a level lower than the boiling point of the vegetable oil. Moreover, an increase in the content of maleic anhydride in the composition over the declared range leads to its free excess in the composition and its additional plasticization. The decrease in the content of maleic anhydride below the stated leads to the ineffective use of rubber devulcanized from rubber crumb, which reduces the softening temperature of the composition and its adhesive ability.

The "exit" of the bitumen concentration value beyond the lower limit of the declared range (below 64.5% - when the total concentration of the remaining components is displayed above 35.5%) reduces the waterproofing properties of the composition, and the "exit" of the bitumen concentration value beyond the upper limit of the claimed range (above 82.7% - with the derivation of the total concentration of the remaining components below 17.3%) leads to the formation of weakly crosslinked coatings, with reduced performance properties.

Signs indicating that in the "process of preparing a rubber-bitumen composition, vegetable oil is placed in a mixer tank and heated to a temperature of 120 ° C, after which bitumen is introduced into it, preferably in a molten state", after which they are mixed, they provide effective plasticization of bitumen, which with the subsequent introduction of rubber crumb, it provides the possibility of its effective devulcanization to obtain a polymer complex, which provides an increase in the performance of the composition.

Signs indicating that after plasticization of bitumen in the mixer, the last one is “introduced crumb rubber and, stirring, heated the mixture to a temperature of 170 ° C and at the same time the operation of mixing the mixture with crumb rubber is carried out for at least an hour”, provide the possibility of creation (with devulcanizable from rubber crumb rubber) polymer complex, providing an increase in the softening temperature and elasticity of the composition after it hardens.

Signs indicating that the temperature of the mixture, including plasticized bitumen and rubber crumb, 170 ° C (and then the addition of maleic anhydride) "support until the composition is finished", provide sufficient speed for the preparation of the composition, the completeness of the polymerization reaction of the mixture and at the same time eliminate part loss components due to evaporation in excess of temperature.

A sign indicating that “the operation of mixing the mixture with rubber crumb is conducted for at least an hour” ensures the full involvement of the components of the mixture in the polymerization reaction. Exceeding this indicator leads to an unjustified increase in the energy intensity of the mixture preparation process.

Signs indicating that upon completion of the previous stage of composition formation (preparation of a mixture of three components), “maleic anhydride is introduced into it and the mixture is stirred for at least half an hour”, they provide a softening temperature of the composition at a level slightly lower than the boiling point of vegetable oil, and improved utilization of rubber devulcanized from rubber crumb.

The features of the second claim specify the brand of bitumen that is optimal to achieve the result of the invention.

The features of the third paragraph of the claims, specifying the characteristics of rubber crumb (lack of additional processing and particle size), minimize the cost of the component due to the lack of additional processing and at the same time (by minimizing particle size) provide a reduction in the duration of the process of its devulcanization.

The signs of the fourth claim provide the possibility of implementing temperature conditions in all operations of the method.

To prepare the composition, use: bitumen grade BND 90/130 (GOST 22245-90) - road oil bitumen; maleic anhydride according to GOST 11153-75; vegetable oil in accordance with GOST 7825-76; rubber crumb - a tire waste product, fraction up to 1.5 mm.

To prepare the composition, devices of known design are used, made in the form of a container equipped with a paddle or screw mixer and means for maintaining the temperature regime of at least 180 ° C.

The composition is prepared and used as follows.

When preparing and using the composition, the following set of safety measures must be observed:

- employees must be provided with personal protective equipment in accordance with GOST 12.4.103 (overalls, aprons, leather shoes, respiratory protection - respirators with an aerosol filter, eye protection - glasses);

- work associated with the use of the composition should be carried out in accordance with the "Sanitary rules for the organization of technological processes and hygienic requirements for production equipment" GOST 12.3.002, GOST 12.3.035;

- work related to the preparation and use of the composition in enclosed spaces should only be carried out with continuously operating supply and exhaust ventilation or with the use of respiratory protection, while the use of open flame is prohibited;

- when working in enclosed spaces, the use of luminaires only in explosion-proof design is permitted;

- Before starting work, it is necessary to check the serviceability of electrical equipment and the presence of grounding to avoid sparking.

The invention is illustrated, but not limited to, by the following examples.

Example 1. 9.04 kg (9.04 wt.%) Plasticizer - vegetable oil is placed in a container and heated to a temperature of 120 ° C. Then, 77 kg (77 wt.%) Of BND 90/30 grade bitumen is introduced there, the resulting mixture is mixed and 13.6 kg (13.6 wt.%) Of rubber crumb of tire waste is added to it. The mixture is then heated to 170 ° C and stirred at a speed of 200 rpm for 60 minutes. Then, while stirring, 0.36 kg (0.36 wt.%) Of maleic anhydride is introduced. The resulting mixture was stirred for 30 minutes at a speed of 200 rpm. After that, the resulting rubber-bitumen composition is ready for further use.

Example 2. 5 kg (5 wt.%) Plasticizer - vegetable oil is placed in a container and heated to a temperature of 120 ° C. Then 80.63 kg (80.63 wt.%) Of BND 90/130 grade bitumen are introduced there, the resulting mixture is mixed and 14 kg (14 wt.%) Of rubber crumb of tire waste is added to it. The mixture is then heated to 170 ° C and stirred at a speed of 200 rpm for 60 minutes. Then, while stirring, 0.37 kg (0.37 wt.%) Of maleic anhydride is introduced. The resulting mixture was stirred for 30 minutes at a speed of 200 rpm. After that, the resulting rubber-bitumen composition is ready for further use.

Example 3. 19.9 kg (19.9 wt.%) Plasticizer - vegetable oil is placed in a container and heated to a temperature of 120 ° C. Then, 67.88 kg (67.88 wt.%) Of BND 90/130 grade bitumen is introduced therein, the resulting mixture is mixed and 12 kg (12 wt.%) Of rubber crumb of tire waste is added to it. The mixture is then heated to 170 ° C and stirred at a speed of 200 rpm for 60 minutes. Then, while stirring, 0.32 kg (0.32 wt.%) Of maleic anhydride is introduced. The resulting mixture was stirred for 30 minutes at a speed of 200 rpm. After that, the resulting rubber-bitumen composition is ready for further use.

Example 4. 20 kg (20 wt.%) Plasticizer - vegetable oil is placed in a container and heated to a temperature of 120 ° C. Then there enter 64.5 kg (64.5 wt.%) Of bitumen grade BND 90/130, the resulting mixture is mixed and 15 kg (15 wt.%) Of crumb rubber waste tires are added to it. The mixture is then heated to 170 ° C and stirred at a speed of 200 rpm for 60 minutes. Then, while stirring, 0.5 kg (0.5 wt.%) Of maleic anhydride are introduced. The resulting mixture was stirred for 30 minutes at a speed of 200 rpm. After that, the resulting rubber-bitumen composition is ready for further use.

Example 5. 9 kg (9 wt.%) Plasticizer - vegetable oil is placed in a container and heated to a temperature of 120 ° C. Then, 77.13 kg (77.13 wt.%) Of bitumen grade BND 90/130 is introduced therein, the mixture is mixed and 13.6 kg (13.6 wt.%) Of rubber crumb of tire waste is added to it. The mixture is then heated to 170 ° C and stirred at a speed of 200 rpm for 60 minutes. Then, while stirring, 0.37 kg (0.37 wt.%) Of maleic anhydride is introduced. The resulting mixture was stirred for 30 minutes at a speed of 200 rpm. After that, the resulting rubber-bitumen composition is ready for further use.

Example 6. 19.9 kg (19.9 wt.%) Plasticizer - vegetable oil is placed in a container and heated to a temperature of 120 ° C. Then, 67.8 kg (67.8 wt.%) Of BND 90/130 grade bitumen is introduced therein, the resulting mixture is mixed and 13.6 kg (13.6 wt.%) Of rubber crumb of tire waste is added to it. The mixture is then heated to 170 ° C and stirred at a speed of 200 rpm for 60 minutes. Then, while stirring, 0.3 kg (0.3 wt.%) Of maleic anhydride are introduced. The resulting mixture was stirred for 30 minutes at a speed of 200 rpm. After that, the resulting rubber-bitumen composition is ready for further use.

Example 7. 13 kg (13 wt.%) Plasticizer - vegetable oil is placed in a container and heated to a temperature of 120 ° C. Then, 73.65 kg (73.65 wt.%) Of bitumen grade BND 90/130 is introduced therein, the resulting mixture is mixed and 13 kg (13 wt.%) Of rubber crumb of tire waste is added to it. The mixture is then heated to 170 ° C and stirred at a speed of 200 rpm for 60 minutes. Then, while stirring, 0.35 kg (0.35 wt.%) Of maleic anhydride are introduced. The resulting mixture was stirred for 30 minutes at a speed of 200 rpm.

The measured temperature characteristics and elasticity of the compositions, the compositions of which are shown in examples 1-7, are presented in table 1.

Table 1 Performance characteristics of bituminous composition Example No. Softening point Fragility temperature Ductility interval Elasticity,% one 57 ° C -35 ° C 92 ° C 76 2 62 ° C -30 ° C 92 ° C 70 3 38 ° C -53 ° C 91 ° C 70 four 44 ° C -55 ° C 99 ° C 75 5 58 ° C -36 ° C 94 ° C 76 6 37 ° C -54 ° C 91 ° C 73 7 52 ° C -42 ° C 94 ° C 77 Prototype 50 ° C -28 ° C 78 ° C <35

The test results obtained according to the invention of rubber-bitumen compositions shown in the table show that they are characterized by much greater intervals of plasticity and elasticity compared with similar characteristics of the prototype.

The finished composition is used as a material for a wide range of applications - it can be used for road, roofing, insulation, sealing works. Moreover, it is preferable to form a protective (insulating) layer or volume from it in a known manner, using known technical means.

Claims (4)

1. A method of preparing a rubber-bitumen composition, comprising preparing a mixture of bitumen, rubber crumb and a plasticizer, characterized in that maleic anhydride is additionally used in the mixture, while vegetable oil is used as a plasticizer, and the above components are used in the composition in the following ratio, wt .%:
Rubber crumb 12.0-15.0 Plasticizer 5.0-20.0 Maleic Anhydride 0.3-0.5 Bitumen Rest,
in addition, in the process of preparing the rubber-bitumen composition, vegetable oil is placed in the container of the mixer and heated to a temperature of 120 ° C, after which bitumen is introduced into it preferably in the molten state, and after mixing, rubber crumb is introduced into the mixer and the resulting mixture is heated to a temperature of 170 ° C, which is maintained until the preparation of the composition is completed, while the operation of mixing the mixture with rubber crumb is carried out for at least an hour, then maleic anhydride is introduced into the mixture and the operation is mixed Testing the resulting mixture is still not less than half an hour. 2. The method according to claim 1, characterized in that they use bitumen grade BND 90/130. 3. The method according to claim 1, characterized in that use rubber crumb tire waste, fractions up to 1.5 mm without additional processing. 4. The method according to claim 1, characterized in that they use a mixer made with the possibility of heating the mixture to 180 ° C.