An emulsified rubber asphalt material and a method for producing the same

Abstract

The present application relates to a kind of emulsified rubber asphalt material and its preparation method, the emulsified rubber asphalt material includes composite colloidal particle modified asphalt and emulsified soap solution, composite colloidal particle modified asphalt in emulsified rubber asphalt material The weight ratio is 40-60%;The preparation method of the composite colloidal particle modified asphalt is: first, low mooney reclaimed rubber is prepared, then low mooney reclaimed rubber and SBS, maleic anhydride are melt blended in closed mill, and composite colloidal particle is prepared by screw extrusion granulation, then composite colloidal particle is added to matrix asphalt, and then rubber oil is added to obtain;The emulsified soap solution is composed of compound cationic emulsifier, self-emulsifying waterborne epoxy resin, stabilizer, pH regulator and deionized water.The emulsified rubber asphalt material prepared by the present application has high emulsification stability, significant high-temperature deformation resistance, low-temperature crack resistance and durability advantage.

Description

Technical Field

[0001] This invention relates to an emulsified rubber asphalt material and its preparation method, belonging to the field of road material preparation technology. Background Technology

[0002] Emulsified asphalt is an emulsion in which asphalt is uniformly dispersed into an aqueous phase as fine droplets under the action of emulsifiers and mechanical force. Compared with hot asphalt and diluted asphalt, emulsified asphalt has significant technical, cost, and environmental advantages. Emulsified asphalt can be directly sprayed as a tack coat, prime coat, and fog seal, and can also be used as a binder for chip seals and penetration pavements. Furthermore, emulsified asphalt can be mixed at room temperature to prepare cold-mix, cold-lay mixtures for preventative road maintenance.

[0003] With the rapid development of my country's social economy, traffic flow and load pressure have increased dramatically. Conventional emulsified asphalt is gradually failing to meet the requirements of asphalt pavement. In particular, emulsified asphalt cannot yet function as a functional structural layer for roads. Various modifiers have been tried to modify emulsified asphalt. Currently, commonly used materials include SBS and SBR latex. SBS has a good modification effect on hot asphalt, but its use in modifying asphalt emulsification involves complex processes, high equipment requirements, high costs, and poor aging resistance. Using SBR latex for modification requires sophisticated raw material production processes. Low-temperature polymerized SBR latex can significantly improve the high and low temperature performance of emulsified asphalt, while high-temperature polymerized SBR latex has a generally poor modification effect and poor high-temperature performance. Furthermore, depending on the charge properties, SBR latex-modified asphalt also requires the use of emulsifiers of the same charge type for emulsification.

[0004] Waste tire rubber is composed of various rubber molecules, such as styrene-butadiene rubber, cis-butadiene rubber, and isoprene rubber. Using waste rubber to modify asphalt to prepare rubberized asphalt effectively improves the low-temperature crack resistance, high-temperature stability, and adhesion to aggregates of asphalt, while also reducing black pollution and lowering production costs, and has been widely used. However, odor has always been a constraint on the development of rubberized asphalt. Emulsification allows for construction at room temperature and eliminates the odor problem. However, due to the limitations of the rubber crosslinking network, the stable preparation of high-performance emulsified rubberized asphalt remains a challenge in the industry.

[0005] Patent CN101173106A discloses a method for preparing rubber powder-asphalt emulsion. This method uses rubber powder with a large particle size and lacks desulfurization pretreatment, resulting in poor rubber dispersibility and poor emulsion stability. Patent CN102660125A discloses a method for preparing waste rubber-modified emulsified asphalt. This method pre-treats the rubber, mixes it with an activator in supercritical CO2, and prepares high-sol-content rubber using a high-temperature, high-pressure method. This rubber is then used to modify and emulsify asphalt. This method is complex and costly, and supercritical CO2 activation of rubber has not yet been industrialized, making practical applications difficult. Furthermore, the stability of the emulsified rubber asphalt has not been reported. Patent CN103881401A discloses a waste rubber powder-modified emulsified asphalt and its preparation method. This method successfully prepares rubber-modified emulsified asphalt, but its long-term stability remains problematic, and its application in mixtures has not been observed. CN105176115B discloses an SBS rubber powder composite modified asphalt, the components of which, by mass parts, are: 15-21 parts waste rubber powder, 2-3 parts SBS modifier, 0.2-0.4 parts stabilizer, 0.03-0.04 parts activator, and 75-82 parts asphalt. The preparation method involves preheating the base asphalt to 180℃, adding the SBS modifier to the hot asphalt and dispersing it under high-speed shear for 20 minutes, then adding the activator, rubber powder, and stabilizer, and dispersing it under high-speed shear at 185℃ for 2 hours. However, the stability of the resulting emulsion is unreliable. Summary of the Invention

[0006] The purpose of this invention is to solve the problems mentioned in the background section and to provide an emulsified rubber asphalt material and its preparation method. The emulsified rubber asphalt material prepared has high emulsification stability, significant advantages in high-temperature deformation resistance, low-temperature crack resistance and durability, and can be used directly on construction sites without the need for on-site compounding.

[0007] The objective of this invention is achieved as follows:

[0008] An emulsified rubber asphalt material, comprising composite granule-modified asphalt and emulsified soap solution, wherein the composite granule-modified asphalt accounts for 40-60% by weight in the emulsified rubber asphalt material; the preparation method of the composite granule-modified asphalt is as follows: firstly, low Mooney reclaimed rubber is prepared, then the low Mooney reclaimed rubber, SBS, and maleic anhydride are subjected to intensive melt blending, and the composite granules are prepared by screw extrusion granulation; then the composite granules are added to the base asphalt, and then rubber oil is added to prepare the final product; the emulsified soap solution is composed of a compound cationic emulsifier, a self-emulsifying waterborne epoxy resin, a stabilizer, a pH adjuster, and deionized water.

[0009] Furthermore, the raw materials for the composite granule modified asphalt consist of composite granules, rubber oil, and base asphalt; the emulsified rubber asphalt material contains 10-30% by weight of composite granules and 1-10% by weight of rubber oil.

[0010] Furthermore, the base bitumen is 70. # Or 90 # Petroleum asphalt for roads.

[0011] Furthermore, the raw materials for the composite granules consist of low Mooney recycled rubber, SBS and maleic anhydride; the mass ratio of the three is (80-90):(5-20):(1-10).

[0012] Furthermore, the preparation process of the low Mooney reclaimed rubber involves desulfurizing rubber powder or waste rubber powder, resulting in a Mooney viscosity of <30; the SBS has a star-shaped or linear structure; and the particle size of the composite rubber particles is less than 6 mm.

[0013] Furthermore, the proportion of compound cationic emulsifier in the emulsified soap solution is 1-8% by weight, the proportion of self-emulsifying waterborne epoxy resin is 5-10% by weight, and the proportion of stabilizer is 1-10‰ by weight.

[0014] Furthermore, the compounded cationic emulsifier is one or more of the following: quaternary ammonium salts, alkylamines, lignin amines, imidazoles, and amide amines.

[0015] Furthermore, the stabilizer is one or more of calcium chloride, magnesium chloride, sodium chloride, and ammonium chloride.

[0016] Furthermore, the pH adjuster is one or more of hydrochloric acid, sulfuric acid, oxalic acid, and formic acid.

[0017] A method for preparing an emulsified rubber asphalt material, characterized by comprising the following steps:

[0018] (1) At 150-300℃, low Mooney reclaimed rubber, SBS, and maleic anhydride are melt-blended and then extruded by screw extrusion to prepare composite granules;

[0019] (2) Heat the base asphalt to a fluid state at 140℃, add composite rubber particles, stir and swell at 160-180℃ for 1h, add rubber oil, shear at 5000rpm at 170-190℃ for 1h, stir and develop at 500rpm for 3h to obtain composite rubber particle modified asphalt.

[0020] (3) Take the compound cationic emulsifier, self-emulsify the waterborne epoxy resin, add 50-60℃ deionized water, add stabilizer, stir quickly and evenly, add pH adjuster to adjust the pH value of the emulsion to 1-3, and obtain emulsified soap solution.

[0021] (4) Add the composite rubber granule modified asphalt and emulsified soap solution to a high-speed shearing machine or colloid mill at the same time, and circulate for 10-20 minutes until the emulsion turns grayish-brown to obtain emulsified rubber asphalt.

[0022] Composite rubber-modified asphalt exhibits significant advantages in high-temperature deformation resistance, low-temperature crack resistance, and durability. However, due to the complex structure of the rubber powder used to prepare composite rubber asphalt and its poor compatibility with asphalt, emulsification of the rubber asphalt is extremely difficult. This invention provides a formulation and process for emulsified rubber asphalt. First, rubber powder is activated to prepare low Mooney recycled rubber. Then, the low Mooney recycled rubber, SBS, and maleic anhydride are melt-blended and subjected to mechanochemical grafting granulation to prepare composite rubber particles. The composite rubber particles are added to asphalt to prepare composite rubber-modified asphalt, and then emulsification of the composite rubber asphalt is successfully achieved by compounding a cationic emulsifier. At an oil-water ratio of 6:4, the evaporation residue content of this emulsified rubber asphalt can reach 59.8%. This material features a simple preparation process, excellent mechanical properties, and high softening point and storage stability. The residual sulfur softening point can reach 89℃, and the 1-day and 5-day storage stability of the product are 0.1% and 0.8%, respectively. This emulsified rubber asphalt can be used in tack coats, stress-absorbing layers, and cold-mix asphalts, exhibiting good construction and road performance.

[0023] Waste rubber powder is a sulfur compound, primarily composed of sulfur bonds, such as SS and CS bonds. Low Mooney reclaimed rubber, after desulfurization, opens these SS and CS bonds, becoming more flexible. When low Mooney reclaimed rubber is dissolved with asphalt, it readily mixes with the asphalt, forming a stable colloidal structure that results in a finer material. Maleic anhydride also promotes emulsification, effectively forming an emulsion. Conventional rubber powder or waste rubber powder, however, cannot be used for emulsification; if forcibly prepared into an emulsion, it will separate into layers within approximately 3 hours, rendering it unusable.

[0024] In addition, low Mooney recycled adhesive itself contains amino groups, which can be emulsified together with epoxy resin in emulsified soap solution. After the product is sprayed and dried, the structure is dense and uniform, and the adhesion is good.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) Give full play to the synergistic effect of reclaimed rubber and SBS composite polymer at the molecular level to make up for the performance shortcomings of single modified asphalt.

[0027] (2) Introducing maleic anhydride mechanochemical grafting improves the compatibility between rubber, SBS and asphalt through the combination of polar functional groups, and also makes it easier to form a stable emulsion.

[0028] (3) Specific low Mooney recycled rubber, SBS, and maleic anhydride are first granulated to form composite rubber particles of a certain size, which can better compatibility with asphalt, make the material more delicate, greatly improve stability, improve the pull-out strength of emulsified asphalt, and improve the adhesion between asphalt and aggregate.

[0029] (4) Through the reasonable compounding of emulsified soap solution, the emulsification and stable storage of reclaimed rubber / SBS modified asphalt can be achieved, and it can be applied to high-performance tack coat oil, cold-mixed and cold-laid mixtures, etc. Detailed Implementation

[0030] The present invention will be further described below with reference to the embodiments.

[0031] The self-emulsifying waterborne epoxy resin was purchased from Tianjin Hengyishengtai Road Construction Materials Technology Co., Ltd., model HY-R. All other components were purchased from standard market models. The low Mooney recycled rubber was produced by desulfurizing waste rubber powder to achieve a Mooney viscosity <30; the SBS has a linear structure; the compounded cationic emulsifier is a 1:1 weight ratio of conventional quaternary ammonium salt emulsifier and alkylamine emulsifier. The stabilizer is calcium chloride. The pH adjuster is hydrochloric acid.

[0032] Example 1

[0033] At 200℃, low Mooney reclaimed rubber, SBS, and maleic anhydride were melt-blended by screw extrusion or internal melt mixing, followed by screw extrusion granulation to prepare composite granules. The composite granules consisted of 8 parts low Mooney reclaimed rubber, 1.7 parts SBS, and 0.3 parts maleic anhydride. The particle size was less than 6 mm.

[0034] Take 5040g of base asphalt and heat it to a fluid state at 140℃. Add 600g of composite rubber granules and stir and swell at 160℃ for 1 hour. Add 360g of rubber oil and shear at 5000rpm at 180℃ for 1 hour. Stir at 500rpm for 3 hours to develop, and obtain 6000g of composite rubber granule modified asphalt.

[0035] Take 80g of compound cationic emulsifier, add 300g of self-emulsifying waterborne epoxy resin, add a certain amount of 50-60℃ deionized water, add 20g of stabilizer, stir quickly and evenly, add pH adjuster to adjust the pH value of the emulsion to 1-3, and obtain 4000g of emulsified soap solution.

[0036] Composite rubber granule modified asphalt and emulsified soap solution are added simultaneously to a high-speed shear mill or colloid mill at a weight ratio of 6:4 and circulated for 10 minutes until the emulsion turns grayish-brown, thus obtaining emulsified rubber asphalt material.

[0037] Example 2

[0038] At 200℃, low Mooney reclaimed rubber, SBS, and maleic anhydride were melt-blended by screw extrusion or internal melt mixing, followed by screw extrusion granulation to prepare composite granules. The composite granules consisted of 8 parts low Mooney reclaimed rubber, 1.7 parts SBS, and 0.3 parts maleic anhydride. The particle size was less than 6 mm.

[0039] Take 5040g of base asphalt and heat it to a fluid state at 140℃. Add 600g of composite rubber granules and stir and swell at 160℃ for 1 hour. Add 360g of rubber oil and shear at 5000rpm at 180℃ for 1 hour. Stir at 500rpm for 3 hours to develop, and obtain 6000g of composite rubber granule modified asphalt.

[0040] Take 120g of compound cationic emulsifier, add 200g of self-emulsifying waterborne epoxy resin, add a certain amount of 50-60℃ deionized water, add 20g of stabilizer, stir quickly and evenly, add pH adjuster to adjust the pH value of the emulsion to 1-3, and obtain 4000g of emulsified soap solution.

[0041] Composite rubber granule modified asphalt and emulsified soap solution are added simultaneously to a high-speed shear mill or colloid mill at a weight ratio of 6:4 and circulated for 10 minutes until the emulsion turns grayish-brown, thus obtaining emulsified rubber asphalt material.

[0042] Comparative Example 1

[0043] It is basically the same as Example 1, except that maleic anhydride is not added.

[0044] Comparative Example 2

[0045] It is basically the same as Example 1, except that the low Mooney recycled rubber is replaced with ordinary waste rubber powder.

[0046] Comparative Example 3

[0047] It is basically the same as Example 1, except that no self-emulsifying waterborne epoxy resin is added.

[0048] Comparative Example 4

[0049] Eight parts of low Mooney recycled rubber, 1.7 parts of SBS, and 0.3 parts of maleic anhydride were directly mixed and stirred evenly to prepare a compound.

[0050] Take 5040g of base asphalt and heat it to a fluid state at 140℃. Add 600g of compound material and stir and swell at 160℃ for 1 hour. Add 360g of rubber oil and shear at 5000rpm at 180℃ for 1 hour. Stir at 500rpm for 3 hours to develop, and obtain 6000g of composite rubber granule modified asphalt.

[0051] Take 80g of compound cationic emulsifier, add 300g of emulsified waterborne epoxy resin, add a certain amount of 50-60℃ deionized water, add 20g of stabilizer, stir quickly and evenly, add pH adjuster to adjust the pH value of the emulsion to 1-3, and obtain 4000g of emulsified soap solution.

[0052] Composite rubber granule modified asphalt and emulsified soap solution are added simultaneously to a high-speed shear mill or colloid mill at a weight ratio of 6:4 and circulated for 10 minutes until the emulsion turns grayish-brown, thus obtaining emulsified rubber asphalt material.

[0053] The materials used in the examples and comparative examples were tested according to standards, and the results are shown in the table below:

[0054] Technical indicators Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Test Specifications Delay speed Slow cracking Slow cracking Slow cracking Cannot emulsify Slow cracking Slow cracking T0658-1993 Evaporation residue content / % 58.9 59.5 59.4 - 58.2 59.0 T0651-1993 Needle penetration / 0.1mm 38.6 37 62 - 44 40 T0604-2011 Softening point / °C 87 89 72 - 78 85 T0606-2011 Ductility (5℃) / cm 22 23 24 - 25 23 T0605-2011 Dynamic viscosity (60℃) / Pa.s 510200 509080 8900 - 207600 486800 T0620-2000 Brinell viscosity (135℃) Pa.s 25.5 26.4 9.6 - 15.3 24.6 T0625-2011 Storage stability (1d) / % 0.2 0.3 0.7 Layering 0.5 Unstable T0655-1993 Storage stability (5d) / % 0.8 0.6 2.1 Layering 0.9 Layering T0655-1993

[0055] The above results indicate that the emulsified rubber asphalt material prepared by the cationic emulsified composite granule modified asphalt method provided by the present invention can significantly improve the high and low temperature performance and storage stability of the modified emulsified rubber asphalt. This enhances the ability of the bonding layer, cold-mixed and cold-laid mixture, etc., to resist various cracks and deformations under alternating vehicle loads and environmental changes when used as road structural layers, thus extending its service life. It has high application and promotion value.

[0056] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An emulsified rubber bituminous material, characterized by, The emulsified rubber asphalt material comprises composite granule-modified asphalt and emulsified soap solution, with the composite granule-modified asphalt accounting for 40-60% by weight in the emulsified rubber asphalt material. The preparation method of the composite granule-modified asphalt is as follows: first, low Mooney reclaimed rubber is prepared; then, the low Mooney reclaimed rubber, SBS, and maleic anhydride are subjected to intensive melt blending, and the mixture is extruded and granulated to prepare composite granules. The composite granules are then added to the base asphalt, followed by the addition of rubber oil to obtain the final product. The emulsified soap solution consists of a compound cationic emulsifier, a self-emulsifying waterborne epoxy resin, a stabilizer, a pH adjuster, and deionized water. The preparation process of the low Mooney reclaimed rubber involves desulfurizing rubber powder or waste rubber powder to achieve a Mooney viscosity <30. The low Mooney reclaimed rubber is an amino-containing low Mooney reclaimed rubber. The SBS has a star-shaped or linear structure. The particle size of the composite granules is less than 6 mm. The emulsified rubber asphalt material is prepared by the following method: (1) At 150-300℃, low Mooney reclaimed rubber, SBS, and maleic anhydride are melt-blended and then extruded by screw extrusion to prepare composite granules; (2) Heat the base asphalt to a fluid state at 140℃, add composite rubber particles, stir and swell at 160-180℃ for 1h, add rubber oil, shear at 5000rpm at 170-190℃ for 1h, stir and develop at 500rpm for 3h to obtain composite rubber particle modified asphalt. (3) Take the compound cationic emulsifier, self-emulsify the waterborne epoxy resin, add 50-60℃ deionized water, add stabilizer, stir quickly and evenly, add pH adjuster to adjust the pH value of the emulsion to 1-3, and obtain emulsified soap solution. (4) Add the composite rubber granule modified asphalt and emulsified soap solution to a high-speed shearing machine or colloid mill at the same time, and circulate for 10-20 minutes until the emulsion turns grayish-brown to obtain emulsified rubber asphalt.

2. An emulsified rubber bituminous material according to claim 1, characterised in that, The raw materials for the composite granule modified asphalt consist of composite granules, rubber oil, and base asphalt; the emulsified rubber asphalt material contains 10-30% by weight of composite granules and 1-10% by weight of rubber oil.

3. An emulsified rubber bituminous material according to claim 1, characterised in that, The base asphalt is 70# or 90# road petroleum asphalt.

4. An emulsified rubber bituminous material according to claim 1, characterised in that, The raw materials for the composite granules consist of low Mooney recycled rubber, SBS and maleic anhydride; the mass ratio of the three is (80-90):(5-20):(1-10).

5. An emulsified rubber bituminous material as claimed in claim 1, wherein, in, The emulsified soap solution contains 1-8% cationic emulsifier by weight, 5-10% self-emulsifying waterborne epoxy resin by weight, and 1-10‰ stabilizer by weight.

6. An emulsified rubber bituminous material according to claim 1, wherein The compounded cationic emulsifier is one or more of the following: quaternary ammonium salts, alkylamines, lignin amines, imidazoles, and amide amines.

7. An emulsified rubber bituminous material according to claim 1, wherein The stabilizer is one or more of calcium chloride, magnesium chloride, sodium chloride, and ammonium chloride.

8. An emulsified rubber bituminous material according to claim 1, wherein, The pH adjuster is one or more of hydrochloric acid, sulfuric acid, oxalic acid, and formic acid.

9. A process for the preparation of an emulsified rubber bituminous material according to any one of claims 1 to 8, characterized in that Includes the following steps: (1) At 150-300℃, low Mooney reclaimed rubber, SBS, and maleic anhydride are melt-blended and then extruded by screw extrusion to prepare composite granules; (2) Heat the base asphalt to a fluid state at 140℃, add composite rubber particles, stir and swell at 160-180℃ for 1h, add rubber oil, shear at 5000rpm at 170-190℃ for 1h, stir and develop at 500rpm for 3h to obtain composite rubber particle modified asphalt. (3) Take the compound cationic emulsifier, self-emulsify the waterborne epoxy resin, add 50-60℃ deionized water, add stabilizer, stir quickly and evenly, add pH adjuster to adjust the pH value of the emulsion to 1-3, and obtain emulsified soap solution. (4) Add the composite rubber granule modified asphalt and emulsified soap solution to a high-speed shearing machine or colloid mill at the same time, and circulate for 10-20 minutes until the emulsion turns grayish-brown to obtain emulsified rubber asphalt.