阅读说明：本技术 冷补橡胶沥青混合液及其制备方法 (Cold-patch rubber asphalt mixed solution and preparation method thereof ) 是由 江宽 董进学 董大伟 刘双旺 李田田 武晋巍 王重阳 冯亚琴 刘晓楠 于 2019-02-26 设计创作，主要内容包括：本发明提供了一种冷补橡胶沥青混合液及其制备方法。该冷补橡胶沥青混合液包括沥青、线性化活性橡胶、烯烃聚合物及稀释剂,其中线性化活性橡胶经由废橡胶粉脱硫处理得到,且线性化活性橡胶中的线性化分子的重量百分含量≥75％。本发明提供的冷补橡胶沥青混合液具有成本低、常温流动性好,应用后强度较高的优势,具有广泛的应用前景。(The invention provides a cold-patch rubber asphalt mixed solution and a preparation method thereof. The cold-patch rubber asphalt mixed solution comprises asphalt, linearized active rubber, olefin polymer and a diluent, wherein the linearized active rubber is obtained by desulfurization treatment of waste rubber powder, and the weight percentage content of linearized molecules in the linearized active rubber is more than or equal to 75%. The cold-patch rubber asphalt mixed solution provided by the invention has the advantages of low cost, good normal-temperature fluidity and higher strength after application, and has wide application prospect.)

1. The cold-patch rubber asphalt mixed solution is characterized by comprising asphalt, linearized active rubber, olefin polymer and diluent, wherein the linearized active rubber is obtained by desulfurization treatment of waste rubber powder, and the weight percentage content of linearized molecules in the linearized active rubber is more than or equal to 75%.

2. The mixed solution of cold-patch rubber and asphalt as claimed in claim 1, wherein the linearized molecules in the linearized active rubber include gradient small molecules and macromolecular polymers, the molecular weight of the gradient small molecules is 500-10000, and the molecular weight of the macromolecular polymers is > 10000; preferably, in the linearized molecule, the weight percentage content of the gradient small molecules is 10-20%, and the weight percentage content of the macromolecular polymer is 80-90%.

3. A cold-patch rubberized asphalt mixture according to claim 1 or 2, wherein the cold-patch rubberized asphalt mixture comprises 100 parts by weight of the asphalt, 15 to 30 parts by weight of the linearized active rubber, 0.5 to 2 parts by weight of the olefin polymer, and 2 to 12 parts by weight of the diluent; preferably, the cold-patch rubber asphalt mixture comprises 100 parts by weight of the asphalt, 20-30 parts by weight of the linearized active rubber, 1-2 parts by weight of the olefin polymer and 2-5 parts by weight of the diluent.

4. The cold patch rubberized asphalt mixture according to claim 3, further comprising 0.05 to 1.5 parts by weight of an elastomeric polymer, 0.05 to 2 parts by weight of a petroleum resin, and 0.1 to 3 parts by weight of an anti-stripping agent.

5. The cold patch rubberized asphalt mixture of claim 4 wherein said elastomeric polymer is selected from one or more of SBS, SEBS, SIS, SBR, EVA and POE; preferably, the petroleum resin is selected from one or more of C5 petroleum resin, C9 petroleum resin, phenolic resin and terpene resin; preferably, the anti-stripping agent is selected from one or more of p-amino benzamide, m-amino benzylamine, a silane coupling agent and sodium lignosulfonate.

6. The cold-patch rubber asphalt mixture liquid as claimed in any one of claims 1 to 5, wherein the molecular weight of the olefin polymer is 3000 to 7000 and the melting point is 90 to 125 ℃; preferably, the olefin polymer is selected from one or more of polyethylene wax, oxidized polyethylene wax, sasobit wax and polyamide wax; preferably, the diluent is selected from diesel and/or kerosene.

7. A method for preparing a cold-patch rubber-asphalt mixture according to any one of claims 1 to 6, comprising the steps of: mixing and dispersing asphalt, linearized active rubber, olefin polymer and a diluent to obtain the cold-patch rubber asphalt mixed solution; the rubber composition is characterized in that the linearized active rubber is obtained by desulfurization treatment of waste rubber powder, and the weight percentage content of linearized molecules in the linearized active rubber is more than or equal to 75%.

8. The method of claim 7, wherein the mixing and dispersing process comprises the steps of:

heating the asphalt to 150-185 ℃, adding the olefin polymer, and stirring for 30-60 min at a stirring speed of 1000-2000 rpm to form a first mixture;

adding the linearized active rubber into the first mixture, and stirring for 60-120 min at the conditions of the temperature of 150-185 ℃ and the stirring speed of 1000-2000 rpm to form a second mixture;

cooling the second mixture to 110-130 ℃, adding the diluent, and stirring for 30-60 min at a stirring speed of 1000-2000 rpm to obtain the cold patch rubber asphalt mixed solution;

preferably, during the addition of the olefin polymer, a petroleum resin is added simultaneously; during the addition of the linearized active rubber, an elastomeric polymer and an anti-spalling agent are added simultaneously.

9. The production method according to claim 7 or 8, characterized in that, before the mixing and dispersing step, the production method further comprises a step of producing the linearized active rubber prepared by a method comprising:

in supercritical carbon dioxide, placing a mixture of waste rubber powder and a photocatalyst under ultraviolet light for photocatalytic desulfurization reaction to obtain the linearized active rubber; preferably, the photocatalyst is a composite inorganic photocatalyst; more preferably, the photocatalyst is selected from Co-doped TiO₂、ZrO₂/ZnO composite and ZrO₂/TiO₂One or more of the complexes; further preferably, the amount of the photocatalyst is 0.5-3% of the weight of the waste rubber powder.

10. The production method according to claim 7 or 8, characterized in that, before the mixing and dispersing step, the production method further comprises a step of producing the linearized active rubber prepared by a method comprising:

pretreating the waste rubber powder and a regenerant at the temperature of 60-150 ℃ for 10-30 min, and standing at the temperature of 50-120 ℃ for 6-36 h to obtain a pretreated product;

extruding the pretreated product in a screw extruder, wherein the extrusion temperature is 100-480 ℃, the extrusion pressure is 3-15 Mpa, and the reaction time is 1-15 min, so as to obtain the linearized active rubber;

preferably, the regenerant comprises a softener selected from one or more of coal tar, pine tar, tall oil, naphthenic oil, dipentene, paraffinic oil, oleic acid, and rosin, and an activator selected from one or more of aromatic disulfide, polyalkylphenol sulfide, phenyl mercaptan, and n-butylamine;

preferably, the weight ratio of the waste rubber powder, the softening agent and the activating agent is 100: (5-30): (0.5-5).

11. The production method according to claim 7 or 8, characterized in that, before the mixing and dispersing step, the production method further comprises a step of producing the linearized active rubber prepared by a method comprising:

placing waste rubber powder into a vertical depolymerizer, adding a solvent, a desulfurization catalyst and a cocatalyst, and then performing desulfurization reaction at the temperature of 160-180 ℃ and under the pressure of 0.5-0.7 MPa to obtain the linearized active rubber; wherein the solvent is paraffin oil and/or solid coumarone, the desulfurization catalyst is phthalic anhydride, and the cocatalyst is formalin and/or resorcinol.

Technical Field

The invention relates to the field of pavement asphalt materials, in particular to a cold-patch rubber asphalt mixed solution and a preparation method thereof.

Background

With the development of the transportation industry, the traffic flow of the road surface is increased day by day, the frequency of road surface damage is increased gradually, and the repair of the pit slots of the road surface is an important link of road surface maintenance. The main mode of pavement repair is to adopt hot asphalt mixture to carry out on-site repair, but the mode is greatly influenced by seasons and can not repair the pits on the pavement on site at any time. The road surface cold patch asphalt material is produced, and has the advantages of simple operation, long storage period, good repair quality, environmental protection and the like, and has very wide application.

The cold construction asphalt mixture sold in the market at present is prepared by diluting viscous asphalt into liquid asphalt, namely adding part of diluent into the viscous asphalt. Such as: the patent CN102702761A discloses a cold patch asphalt modified liquid and a preparation method thereof, wherein the modified liquid is prepared from 5-8% of SBR and/or SBS, 3-5% of naphthenic oil, 3-5% of glycerol, 3-5% of dibutyl ester, 0-3% of anti-stripping agent and the balance of heavy diesel oil. Patent CN105001656B discloses a normal temperature asphalt modifier, normal temperature modified asphalt and warm-mix cold-paving asphalt concrete, wherein the normal temperature asphalt modifier is a mixture comprising waste engine oil, rubber tires and plastic extracts; the modified asphalt is obtained by adding a normal-temperature asphalt modifier into matrix asphalt at 130-150 ℃ and stirring. The normal temperature asphalt modifier in the scheme is a high molecular alloy of a high molecular interpenetrating network formed by blending three or more than three high molecular polymers of waste engine oil, rubber tires, plastic extracts and the like. The patent CN106116270A discloses a cold-patch asphalt mixture used in the freezing period and a preparation method thereof, wherein a cold patch liquid comprises 12-15% of diluent, 2-4% of petroleum resin, 8-10% of rubber powder, 2-4% of aromatic oil, 1.5-2% of dispersing agent and the balance of No. 90 grade A asphalt.

However, the current cold-patch rubber asphalt has the following defects:

defect one: the existing cold patch asphalt basically comprises asphalt, an elastomer polymer, small molecular solvent oil, a volatile diluent and petroleum resin. The addition of petroleum resin and elastomer polymer in a large proportion causes the cold patch asphalt to have higher cost, which is not beneficial to the market popularization and application of the technology;

and defect two: the addition of the small molecular solvent oil can increase the normal temperature fluidity of the asphalt, but can also cause the asphalt to be further softened, and seriously affect the strength of the cold-patch asphalt mixture;

and a third defect: if the waste rubber powder is added to replace part of the elastomer polymer in consideration of cost, the cold patch asphalt is thickened due to strong oil absorption swelling capacity of the waste rubber powder due to the crosslinking property of the waste rubber powder, so that the normal-temperature viscosity of the cold patch asphalt is increased, and the cold patch asphalt is not favorable for storage and mixing; meanwhile, the cross-linked state of the rubber powder limits the chain motion capability of the macromolecular rubber, and the contribution to the strength of the macromolecular rubber in the cold patch asphalt is insufficient.

For the reasons, it is necessary to provide a cold patch rubber asphalt mixture with low cost, good normal temperature fluidity and high strength after application.

Disclosure of Invention

The invention mainly aims to provide a cold-patch rubber asphalt mixed solution and a preparation method thereof, and aims to solve the problems in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a cold-patch rubber-asphalt mixture comprising asphalt, a linearized active rubber, an olefin polymer and a diluent, wherein the linearized active rubber is obtained by desulfurization treatment of waste rubber powder, and the weight percentage of linearized molecules in the linearized active rubber is greater than or equal to 75%.

Further, the linearized molecules in the linearized active rubber comprise gradient small molecules and macromolecular polymers, the molecular weight of the gradient small molecules is 500-10000, and the molecular weight of the macromolecular polymers is more than 10000; preferably, in the linearized molecules, the weight percentage of the gradient small molecules is 10-20%, and the weight percentage of the macromolecular polymer is 80-90%.

Further, the cold-patch rubber asphalt mixed solution comprises 100 parts by weight of asphalt, 15-30 parts by weight of linearized active rubber, 0.5-2 parts by weight of olefin polymer and 2-12 parts by weight of diluent; preferably, the cold-patch rubber asphalt mixture comprises 100 parts by weight of asphalt, 20-30 parts by weight of linearized active rubber, 1-2 parts by weight of olefin polymer and 2-5 parts by weight of diluent.

Furthermore, the cold-patch rubber asphalt mixed solution also comprises 0.05 to 1.5 parts by weight of elastomer polymer, 0.05 to 2 parts by weight of petroleum resin and 0.1 to 3 parts by weight of anti-stripping agent.

Further, the elastomer polymer is selected from one or more of SBS, SEBS, SIS, SBR, EVA and POE; preferably, the petroleum resin is selected from one or more of C5 petroleum resin, C9 petroleum resin, phenolic resin and terpene resin; preferably, the anti-stripping agent is selected from one or more of p-aminobenzamide, m-aminobenzylamine, a silane coupling agent and sodium lignosulfonate.

Further, the olefin polymer has a molecular weight of 3000 to 7000 and a melting point of 90 to 125 ℃; preferably, the olefin polymer is selected from one or more of polyethylene wax, oxidized polyethylene wax, sasobit wax and polyamide wax; preferably, the diluent is selected from diesel and/or kerosene.

According to another aspect of the present invention, there is also provided a method for preparing a cold patch rubber asphalt mixture, comprising the following steps: mixing and dispersing asphalt, linearized active rubber, olefin polymer and a diluent to obtain a cold-patch rubber asphalt mixed solution; wherein the linearized active rubber is obtained by desulfurization treatment of waste rubber powder, and the weight percentage content of linearized molecules in the linearized active rubber is more than or equal to 75%.

Further, the mixing and dispersing process comprises the following steps: heating the asphalt to 150-185 ℃, adding an olefin polymer, and stirring for 30-60 min at a stirring speed of 1000-2000 rpm to form a first mixture; adding linear active rubber into the first mixture, and stirring for 60-120 min at the conditions that the temperature is 150-185 ℃ and the stirring speed is 1000-2000 rpm to form a second mixture; cooling the second mixture to 110-130 ℃, adding a diluent, and stirring for 30-60 min at a stirring speed of 1000-2000 rpm to obtain a cold-patch rubber asphalt mixed solution; preferably, during the addition of the olefin polymer, petroleum resin is added simultaneously; during the addition of the linearized active rubber, the elastomeric polymer and the antistripping agent are added simultaneously.

Further, before the mixing and dispersing step, the preparation method further comprises the step of preparing a linearized active rubber prepared by the following method: in supercritical carbon dioxide, placing a mixture of waste rubber powder and a photocatalyst under ultraviolet light for photocatalytic desulfurization reaction to obtain linear active rubber; preferably, the photocatalyst is a composite inorganic photocatalystAn agent; more preferably, the photocatalyst is selected from Co-doped TiO₂、ZrO₂/ZnO composite and ZrO₂/TiO₂One or more of the complexes; further preferably, the amount of the photocatalyst is 0.5 to 3% by weight of the waste rubber powder.

Further, before the mixing and dispersing step, the preparation method further comprises the step of preparing a linearized active rubber prepared by the following method: pretreating the waste rubber powder and a regenerant at the temperature of 60-150 ℃ for 10-30 min, and standing at the temperature of 50-120 ℃ for 6-36 h to obtain a pretreated product; extruding the pretreated product in a screw extruder, wherein the extrusion temperature is 100-480 ℃, the extrusion pressure is 3-15 Mpa, and the reaction time is 1-15 min to obtain the linear active rubber; preferably, the regenerant comprises a softener selected from one or more of coal tar, pine tar, tall oil, naphthenic oil, dipentene, paraffin oil, oleic acid and rosin, and an activator selected from one or more of aromatic disulfide, polyalkylphenol sulfide, phenyl mercaptan and n-butylamine; preferably, the weight ratio of the waste rubber powder to the softener to the activator is 100: (5-30): (0.5-5).

Further, before the mixing and dispersing step, the preparation method further comprises the step of preparing a linearized active rubber prepared by the following method: placing waste rubber powder into a vertical depolymerizer, adding a solvent, a desulfurization catalyst and a cocatalyst, and then performing desulfurization reaction at the temperature of 160-180 ℃ and under the pressure of 0.5-0.7 MPa to obtain linear active rubber; wherein the solvent is paraffin oil and/or solid coumarone, the desulfurization catalyst is phthalic anhydride, and the cocatalyst is formalin and/or resorcinol.

The invention provides a cold-patch rubber asphalt mixed solution which comprises asphalt, linearized active rubber, olefin polymer and a diluent, wherein the linearized active rubber is obtained by desulfurization treatment of waste rubber powder, and the weight percentage content of linearized molecules in the linearized active rubber is more than or equal to 75%.

The cold-patch rubber asphalt mixed solution provided by the invention is added with the linear active rubber with the weight percentage content of linear molecules being more than or equal to 75% on the basis of asphalt. Most of rubber molecules in the linearized active rubber are linearized molecules, the flexible chain structure of the rubber molecules is reserved, the linearized active rubber has performance similar to that of an elastomer polymer, the linearized active rubber can replace the elastomer polymer to be applied to cold patch asphalt, the strength of the cold patch asphalt is enhanced, and meanwhile, the cost of the cold patch asphalt can be greatly reduced. Meanwhile, compared with the cross-linked waste rubber powder, the cross-linked structure of the linear active rubber is basically damaged, and the capability of absorbing light components and diluents of the asphalt is greatly weakened, so that the linear active rubber can be added in a large proportion, and the normal temperature fluidity of the cold patch asphalt is not influenced while the performance of the cold patch asphalt is enhanced. In addition, the addition of the olefin polymer can further enhance the strength of the cold patch asphalt.

In a word, the cold-patch rubber asphalt mixed solution provided by the invention has the advantages of low cost, good normal-temperature fluidity and higher strength after application, and has wide application prospect.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

As described in the background of the invention section, the cold patch asphalt in the prior art has the problems of high cost or poor normal temperature fluidity and low strength after application.

In order to solve the problems, the invention provides a cold-patch rubber asphalt mixed solution which comprises asphalt, linearized active rubber, olefin polymer and diluent, wherein the linearized active rubber is obtained by desulfurization treatment of waste rubber powder, and the weight percentage content of linearized molecules in the linearized active rubber is more than or equal to 75%.

In the practical application process, the cold-patch rubber asphalt mixed solution is mixed with aggregate and then can be used as a cold-patch asphalt mixture for repairing damaged parts of a pavement.

The cold-patch rubber asphalt mixed solution provided by the invention is added with the linear active rubber with the weight percentage content of linear molecules being more than or equal to 75% on the basis of asphalt. Most of rubber molecules in the linearized active rubber are linearized molecules, the flexible chain structure of the rubber molecules is reserved, the linearized active rubber has performance similar to that of an elastomer polymer, the linearized active rubber can replace the elastomer polymer to be applied to cold patch asphalt, the strength of the cold patch asphalt is enhanced, and meanwhile, the cost of the cold patch asphalt can be greatly reduced. Meanwhile, compared with the cross-linked waste rubber powder, the cross-linked structure of the linear active rubber is basically damaged, and the capability of absorbing light components and diluents of the asphalt is greatly weakened, so that the linear active rubber can be added in a large proportion, and the normal temperature fluidity of the cold patch asphalt is not influenced while the performance of the cold patch asphalt is enhanced.

In addition, the double bond content of the olefin polymer is low, the hard chain segment content is high, the strength of the olefin polymer is higher than that of the linearized active rubber, and the compounded olefin polymer can strengthen the molecular network in the molecular network of the linearized active rubber and further strengthen the strength of the cold-patch asphalt.

In a word, the cold-patch rubber asphalt mixed solution provided by the invention has the advantages of low cost, good normal-temperature fluidity and higher strength after application, and has wide application prospect.

The linear active rubber adopted in the cold patch rubber asphalt mixed solution is obtained by desulfurization treatment of waste rubber powder, and the weight percentage content of linear molecules in the linear active rubber is more than or equal to 75%, so that the linear active rubber can be applied to cold patch asphalt instead of elastomer polymers, the strength of the cold patch asphalt is enhanced, and meanwhile, the cost of the cold patch asphalt can be greatly reduced. In a preferred embodiment, the linearized molecules in the linearized active rubber comprise a gradient of small molecules with a molecular weight of 500 to 10000 and a macromolecular polymer with a molecular weight > 10000. The macromolecular polymer with the molecular weight more than 10000 can more effectively exert the low-temperature flexibility and elasticity of the rubber, has a molecular chain structure more similar to that of an elastomer polymer and a molecular weight more close to that of the elastomer polymer, can more fully replace the application of the macromolecular polymer in cold patch asphalt, and enhances the strength of the cold patch asphalt. The molecular weight of the gradient micromolecules with the molecular weight of 500-10000 is larger than that of the traditional micromolecule solvent oil, and the softening degree of the asphalt can be reduced while plasticizing the asphalt, so that the micromolecule solvent oil can be replaced, the dosage of a diluent can be correspondingly reduced, and the cold patch asphalt further assists in increasing the strength of the cold patch asphalt while keeping the normal-temperature fluidity.

More preferably, in the linearized molecules, the weight percentage of the gradient small molecules is 10-20%, and the weight percentage of the macromolecular polymer is 80-90%. Therefore, the comprehensive effect of the two components is more favorably exerted, the characteristics of the linear active rubber are fully exerted, the strength and the normal temperature fluidity of the cold patch asphalt are improved, and the excessively low softening point of the cold patch rubber asphalt is further avoided.

In order to further improve the comprehensive performance of the cold-patch rubber asphalt mixed solution, in a preferred embodiment, the cold-patch rubber asphalt mixed solution comprises 100 parts of asphalt, 15-30 parts of linearization active rubber, 0.5-2 parts of olefin polymer and 2-12 parts of diluent by weight; preferably, the cold-patch rubber asphalt mixture comprises 100 parts by weight of asphalt, 20-30 parts by weight of linearized active rubber, 1-2 parts by weight of olefin polymer and 2-5 parts by weight of diluent. As described above, the linear active rubber is adopted in the invention, so that the linear active rubber can maintain the properties such as strength, normal temperature fluidity and the like of the cold patch asphalt on the basis of large-proportion addition, and particularly can fully replace an elastomer polymer to reduce the cost of the cold patch asphalt.

In order to further improve various performances of the cold patch asphalt, in a preferred embodiment, the cold patch rubber asphalt mixed solution further comprises 0.05-1.5 parts of elastomer polymer, 0.05-2 parts of petroleum resin and 0.1-3 parts of anti-stripping agent by weight. The cold-patch asphalt has better comprehensive performance by adding the elastomer polymer and the petroleum resin in lower parts by weight. The addition of the anti-stripping agent is beneficial to improving the anti-stripping property of the cold patch asphalt.

The elastomeric polymers, petroleum resins, anti-stripping agents, etc. described above may be of the type conventionally used in cold patch asphalt, and in a preferred embodiment, the elastomeric polymers include, but are not limited to, one or more of SBS, SEBS, SIS, SBR, EVA, and POE; preferably, the petroleum resin includes, but is not limited to, one or more of C5 petroleum resin, C9 petroleum resin, phenolic resin, and terpene resin; preferably, the anti-stripping agent includes, but is not limited to, one or more of para-amino-benzamide, meta-amino benzylamine, silane coupling agent, and sodium lignosulfonate.

In a preferred embodiment, the olefin polymer has a molecular weight of 3000 to 7000 and a melting point of 90 to 125 ℃. The olefin polymer with small molecular weight has small influence on the normal temperature fluidity of the asphalt, and is beneficial to enhancing the cold patch asphalt and keeping the normal temperature fluidity of the cold patch asphalt. Preferably, the olefin polymer includes, but is not limited to, one or more of polyethylene wax, oxidized polyethylene wax, sasobit wax, and polyamide wax.

Preferably, the diluent includes, but is not limited to, diesel and/or kerosene.

According to another aspect of the present invention, there is also provided a method for preparing a cold patch rubber asphalt mixture, comprising the following steps: mixing and dispersing asphalt, linearized active rubber, olefin polymer and a diluent to obtain a cold-patch rubber asphalt mixed solution; wherein the linearized active rubber is obtained by desulfurization treatment of waste rubber powder, and the weight percentage content of linearized molecules in the linearized active rubber is more than or equal to 75%.

By adopting the preparation method, the asphalt, the linearized active rubber, the olefin polymer and the diluent are mixed and dispersed to obtain the cold-patch rubber asphalt mixed solution. On the basis of asphalt, linear active rubber with the weight percentage content of linear molecules being more than or equal to 75 percent is added. Most of rubber molecules in the linearized active rubber are linearized molecules, the flexible chain structure of the rubber molecules is reserved, the rubber molecules have the performance similar to that of an elastomer polymer, the elastomer polymer can be replaced to be applied to cold patch asphalt, the strength of the cold patch asphalt is enhanced, and meanwhile, the cost of the cold patch asphalt can be greatly reduced. Meanwhile, compared with the cross-linked waste rubber powder, the cross-linked structure of the linear active rubber is basically damaged, and the capability of absorbing light components and diluents of the asphalt is greatly weakened, so that the linear active rubber can be added in a large proportion, and the normal temperature fluidity of the cold patch asphalt is not influenced while the performance of the cold patch asphalt is enhanced. In addition, the double bond content of the olefin polymer is low, the hard chain segment content is high, the strength of the olefin polymer is higher than that of the linearized active rubber, and the compounded olefin polymer can strengthen the molecular network in the molecular network of the linearized active rubber and further strengthen the strength of the cold-patch asphalt.

The process conditions in the preparation process can be adjusted, and preferably, the mixing and dispersing process comprises the following steps: heating the asphalt to 150-185 ℃, adding an olefin polymer, and stirring at a stirring speed of 1000-2000 rpm for 30-60 ℃ while maintaining the temperature to form a first mixture; adding linear active rubber into the first mixture, and stirring at the temperature of 150-185 ℃ and the stirring speed of 1000-2000 rpm for 60-120 ℃ in a heat preservation manner to form a second mixture; and cooling the second mixture to 110-130 ℃, adding a diluent, and stirring for 30-60 min at the stirring speed of 1000-2000 rpm to obtain the cold-patch rubber asphalt mixed solution.

Preferably, during the addition of the olefin polymer, petroleum resin is added simultaneously; during the addition of the linearized active rubber, the elastomeric polymer and the antistripping agent are added simultaneously.

Before the mixing and dispersing step, the preparation method further comprises a step of preparing the linearized active rubber, wherein the linearized active rubber can be prepared by performing physical shearing desulfurization or high-temperature boiling degradation on the waste rubber powder, and the preparation method preferably comprises the following steps:

physical shearing desulfurization:

pretreating the waste rubber powder and a regenerant at the temperature of 60-150 ℃ for 10-30 min, and standing at the temperature of 50-120 ℃ for 6-36 h to obtain a pretreated product; and extruding the pretreated product in a screw extruder, wherein the extrusion temperature is 100-480 ℃, the extrusion pressure is 3-15 Mpa, and the reaction time is 1-15 min, so as to obtain the linear active rubber. Preferably, the regenerant comprises a softener selected from one or more of coal tar, pine tar, tall oil, naphthenic oil, dipentene, paraffin oil, oleic acid, and rosin, and an activator selected from one or more of aromatic disulfide, polyalkylphenol sulfide, phenyl mercaptan, and n-butylamine. Preferably, the weight ratio of the waste rubber powder to the softener to the activator is 100: (5-30): (0.5-5).

Degradation by a high-temperature boiling method:

placing waste rubber powder into a vertical depolymerizer, adding a solvent, a desulfurization catalyst and a cocatalyst, and then performing desulfurization reaction at the temperature of 160-180 ℃ and under the pressure of 0.5-0.7 MPa to obtain linear active rubber; wherein the solvent is paraffin oil and/or solid coumarone, the desulfurization catalyst is phthalic anhydride, and the cocatalyst is formalin and/or resorcinol. Preferably, the raw materials in the preparation method comprise the following components in parts by weight: 100 parts of 20-50 mesh waste rubber powder, 70-90 parts of paraffin oil, 10-30 parts of solid coumarone, 2-5 parts of phthalic anhydride, 4-6 parts of formaldehyde aqueous solution and 0.2-0.5 part of resorcinol.

Compared with the physical shearing desulfurization or high-temperature boiling degradation, the more preferable linear active rubber is prepared by adopting the following method:

in supercritical carbon dioxide, the mixture of waste rubber powder and photocatalyst is put under ultraviolet light for photocatalytic desulfurization reaction to obtain the linearized active rubber. The waste rubber powder can be swelled by using the supercritical carbon dioxide, so that the aperture of the three-dimensional cross-linked network in the waste rubber powder is increased, and the photocatalyst is permeated into the waste rubber powder from the surface by virtue of the diffusion effect of the supercritical carbon dioxide fluid. Secondly, the photocatalyst generates a large amount of active groups under the irradiation of ultraviolet light to catalyze the breakage of S-S bonds in the waste rubber powder, thereby realizing the desulfurization and crosslinking of the waste rubber powder. Particularly, since the supercritical carbon dioxide also has an excellent dissolving effect, the linear molecules formed by the desulfurization and de-crosslinking on the surface of the waste rubber powder can be rapidly peeled off from the surface of the waste rubber powder and dissolved in the supercritical carbon dioxide. Along with the continuous reaction, the waste rubber powder continuously carries out the cyclic reciprocating of 'catalyst surface permeation, photocatalytic desulfurization and desulfurization linear molecule stripping dissolution' until the waste rubber powder integrally completes desulfurization and de-crosslinking to form the linear active rubber.

Different from the mechanical shearing desulfurization regeneration method, the photocatalytic desulfurization is carried out under the swelling action of supercritical carbon dioxide, so that the method has higher selectivity on the breaking point of a cross-linked network, and the breaking point is mostly at the S-S bond cross-linking part. While the breaking point of mechanical shear desulfurization is a diversified breaking point that is not selective for S-S bond crosslinks. Therefore, based on the preparation method, the linearization structure of the rubber can be more completely maintained, and the regenerated linearization active rubber has higher molecular weight and correspondingly maintains higher performance.

Compared with the mode of degradation by a high-temperature boiling method, the photocatalytic desulfurization is carried out under the swelling action of the supercritical carbon dioxide without adding a chemical desulfurizer, so that the problems of delayed vulcanization, secondary degradation and the like caused by chemical desulfurization and residue are avoided. Meanwhile, a large amount of softening aids are not added to the high-temperature boiling method, so that the influence of the softening aids on the performance of the cold patch asphalt, such as the influence on the strength of the cold patch asphalt, can be avoided.

The above-mentioned photocatalyst may be of a type commonly used in the field of photocatalytic technology. In a preferred embodiment, the photocatalyst is a composite inorganic photocatalyst. The composite inorganic photocatalyst has higher catalytic activity and higher selective fracture performance on S-S crosslinking points in the waste rubber powder. More preferably, the photocatalyst is selected from Co-doped TiO₂、ZrO₂/ZnO composite and ZrO₂/TiO₂One or more of the complexes. The surface areas of the composite inorganic photocatalysts are greatly increased, so that the probability of exciting the photohole electrons under ultraviolet irradiation is further increased, and the composite inorganic photocatalysts have higher catalytic activity. Meanwhile, the photocatalysts are remained in the linearized active rubber and are more suitable as fillers of the linearized active rubber, and the photocatalysts can play a certain auxiliary role in reinforcing cold patch asphalt.

In a preferred embodiment, the preparation method comprises the following steps: mixing waste rubber powder with a photocatalyst to obtain a mixture; under the condition of stirring, putting the mixture into supercritical carbon dioxide for swelling treatment to obtain a swelling mixture; and irradiating ultraviolet light to the swelling mixture in supercritical carbon dioxide to perform photocatalytic desulfurization reaction, thereby obtaining the linearized active rubber.

Thus, mixing the waste rubber powder with the photocatalyst in advance enables the photocatalyst to be dispersed in the waste rubber powder in advance. Secondly, the mixture is placed in supercritical carbon dioxide under the condition of stirring for swelling treatment, so that the diffusion effect of supercritical carbon dioxide fluid can be more fully exerted, the waste rubber powder is swelled as soon as possible, and the photocatalyst is enabled to permeate into the surface of the waste rubber powder more quickly. Finally, irradiating ultraviolet light to the system for photocatalytic desulfurization reaction. In the actual operation process, the desulfurization efficiency of the waste rubber powder can be further improved according to the process.

In a preferred embodiment, the swelling treatment step comprises: injecting carbon dioxide gas into a system in which the mixture is located, and then adjusting the temperature of the system to 80-140 ℃ and the pressure to 10-35 MPa to convert the carbon dioxide gas into a supercritical state so as to form supercritical carbon dioxide; and swelling the mixture for 30-120 min under the stirring condition that the stirring speed is 200-700 rpm, so as to obtain a swelling mixture. The swelling treatment is carried out in the technical process, the aperture of the cross-linked network of the waste rubber powder is larger, and the photocatalyst can be more fully permeated and more uniformly dispersed in the rubber network, so that on one hand, the desulfurization efficiency of the waste rubber powder can be further improved, and simultaneously, the fracture number of S-S bonds can be further improved, thereby improving the desulfurization degree of the waste rubber powder and obtaining the desulfurized rubber with higher linearization degree.

More preferably, the swelling treatment step comprises: injecting carbon dioxide gas into a system in which the mixture is located, and then adjusting the temperature of the system to 105-140 ℃ and the pressure to 28-35 MPa to convert the carbon dioxide gas into a supercritical state so as to form supercritical carbon dioxide; and swelling the mixture for 90-120 min under the condition that the stirring speed is 500-700 rpm, so as to obtain a swelling mixture. The desulfurization efficiency and desulfurization degree under the process condition are higher.

In a preferred embodiment, in the step of photocatalytic desulfurization, the reaction temperature is 80-140 ℃ and the reaction pressure is 10-35 MPa. Under the reaction conditions, the S-S bond desulfurization selectivity of the photocatalyst is higher, and the desulfurization degree and the desulfurization linearization degree of the waste rubber powder are higher. More preferably, the reaction temperature in the step of the photocatalytic desulfurization reaction is 105-140 ℃, and the reaction pressure is 28-35 MPa. In the actual production process, after the photocatalytic desulfurization reaction is finished, the method preferably further comprises the following steps: and (3) decompressing the reaction system, recovering carbon dioxide, stopping illumination and cooling to obtain the linearized active rubber.

In a preferred embodiment, in the step of photocatalytic desulfurization, the illumination time of the ultraviolet light is 5 to 30min, preferably 20 to 30min, and the wavelength of the ultraviolet light is 300 to 400nm, preferably 350 to 390 nm. Under the illumination condition, the photocatalyst has higher activity, and the desulfurization effect of the waste rubber powder is better.

In a preferred embodiment, the step of mixing the waste rubber powder with the photocatalyst comprises: and stirring and mixing the waste rubber powder and the photocatalyst for 5-30 min under the condition that the stirring speed is 700-1500 rpm to obtain a mixture. The waste rubber powder and the photocatalyst are mixed according to the process, and the waste rubber powder and the photocatalyst can be mutually dispersed more fully. Preferably, the waste rubber powder and the photocatalyst are stirred and mixed to the temperature of 60-85 ℃ to obtain a mixture. Shear heating can occur in the stirring process, the stirring and mixing temperature is controlled to be 60-85 ℃, and performance influence caused by overheating can be prevented on the basis of sufficient dispersion.

As described above, based on the diffusibility and good solubility of supercritical carbon dioxide, the cyclic process of "catalyst surface permeation-photocatalytic desulfurization-desulfurization linear molecule stripping dissolution" is continuously performed in the step of photocatalytic desulfurization reaction of waste rubber powder, which enables the preparation method to achieve a higher desulfurization degree by using the cyclic process with less photocatalyst. For the purpose of saving energy and improving the desulfurization efficiency and the desulfurization degree, in a preferred embodiment, the amount of the photocatalyst is 0.5 to 3% by weight, preferably 2 to 3% by weight, based on the waste rubber powder.

In a preferred embodiment, the particle size of the waste rubber powder is 80-120 meshes; preferably, the waste rubber powder is one or more of waste tire rubber powder, waste mechanical tire rubber powder, waste sole rubber powder and waste conveyor belt rubber powder.

In addition, the preparation method is suitable for waste rubber powder commonly used in the field, such as one or more of waste nitrile rubber powder, waste natural rubber powder, waste butyl rubber powder, waste ethylene propylene rubber powder and waste styrene butadiene rubber powder.

The beneficial effects of the present invention are further illustrated by the following examples:

preparation of linearized active rubber: