High-weather-resistance composite modified road hot-melt coating and low-temperature preparation process thereof

Abstract

The invention discloses a high-weather-resistance composite modified road hot-melt coating and a low-temperature preparation process thereof, and relates to the technical field of road engineering materials. Comprising 35-50 parts of a composite resin matrix, 15-20 parts of a gradient interface reinforcing agent, 18-25 parts of a nano composite filler, 8-12 parts of a low-temperature toughening network agent and 5-8 parts of a dynamic self-repairing agent. The material still keeps high elongation at break at-30 DEG C through the composite resin matrix, interface modified filler is prepared through the gradient interface reinforcing agent and the nano composite filler, interface bonding strength is enhanced, filler agglomeration is prevented, coating master batch is combined with the dynamic self-repairing agent, and the dynamic self-repairing coating has the advantages that the dynamic self-repairing coating has excellent mechanical properties, and the service life of the dynamic self-repairing coating is prolonged. The dynamic self-repairing capability is realized, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering materials, and particularly to a highly weather-resistant composite modified road hot-melt coating and a low-temperature preparation process thereof. Background Art

[0002] As an indispensable material in traffic infrastructure, road hot-melt coatings have been widely used globally due to their advantages such as convenient construction, good abrasion resistance, and strong adhesion. Traditional hot-melt coatings mainly use petroleum resins, thermoplastic resins, etc. as substrates, and their performance is easily affected by environmental factors such as ultraviolet rays, temperature changes, acid rain, and humidity, resulting in problems such as coating aging, cracking, and peeling. Especially in high-altitude areas, where the temperature difference between day and night is large and the ultraviolet radiation is strong, the service life of existing coatings is significantly shortened, seriously affecting road safety and maintenance costs.

[0003] The Chinese invention patent with the publication number CN106337349A discloses a two-step self-healing method for cement pavement caulking materials based on the shape memory effect. First, a pre-deformation method is used to endow the caulking materials with shape memory function in the horizontal direction and store pre-compression strain energy; when the temperature rises, the caulking materials installed in the cement pavement joints close at the macroscopic structural scale under the shape recovery force; the thermoplastic polymer nanoparticles pre-buried in the caulking materials melt, and cross-linking polymerization and curing reactions occur to achieve self-healing at the molecular scale; observe the closure of cracks or damages at the structural scale to understand the self-healing process of cracks or damages at the macroscopic structural scale; measure the interfacial binding energy between two free surfaces to evaluate the self-healing effect at the molecular scale between two free surfaces. This invention can repeatedly achieve self-healing of cracks at the macroscopic scale of caulking materials and improve the durability of caulking materials.

[0004] Existing highly weather-resistant composite modified road hot-melt coatings will have problems such as restricted movement of resin molecular chain segments, phase separation of elastomeric modifiers, and reduced interfacial bonding strength between fillers and resins in a low-temperature environment of -20°C, resulting in a significant embrittlement phenomenon of the material. At the same time, under the cyclic stress of vehicle dynamic rolling loads, stress concentration areas inside the coating film (such as defects like filler agglomerations and microvoids) will preferentially generate microcracks, and due to the low-temperature environment severely inhibiting the plastic deformation and stress relaxation capabilities of the resin, the cracks will rapidly expand and penetrate each other, leading to fatigue failure of the coating film within a period far lower than the designed service life. Summary of the Invention

[0005] The purpose of the present invention is to provide a highly weather-resistant composite modified road hot-melt coating and a low-temperature preparation process thereof to solve the problems raised in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A highly weather-resistant composite modified road hot-melt coating, comprising 35-50 parts of a composite resin matrix, 15-20 parts of a gradient interface enhancer, 18-25 parts of a nano-composite filler, 8-12 parts of a low-temperature toughening network agent, and 5-8 parts of a dynamic self-healing agent.

[0007] Furthermore, the composite resin matrix comprises ethylene-vinyl acetate copolymer, hydrogenated styrene-isoprene-styrene block copolymer, and polyether-type polyurethane in a mass ratio of (20-25):(12-15):(8-10);

[0008] The gradient interface enhancer comprises epoxy groups, carboxyl groups, and zwitterionic groups in a mass ratio of 1:(0.33-0.79):(0.72-1.8);

[0009] The nano-composite filler comprises component materials, a silane coupling agent, and a titanate coupling agent in a mass ratio of (7.2-16.7):1:(0.32-0.8).

[0010] Furthermore, the component materials comprise silica and alumina in a mass ratio of (2.7-3.3):1, and the diameter of the spherical silica is 50-100 nm, and the thickness of the flaky alumina is 20-50 nm.

[0011] Furthermore, the silane coupling agent and the titanate coupling agent cover the surface of the component materials, and the surface coverage thickness of the component materials is 3-8 nm. At the same time, the coverage rate of the silane coupling agent is 60-70%, and the coverage rate of the titanate coupling agent is 30-40%.

[0012] A low-temperature preparation process of a highly weather-resistant composite modified road hot-melt coating, preparing the highly weather-resistant composite modified road hot-melt coating described in any one of the above, comprising the following steps:

[0013] S1: Premixing of matrix materials: Melting and mixing ethylene-vinyl acetate copolymer and hydrogenated styrene-isoprene-styrene block copolymer, and after mixing, adding polyether-type polyurethane particles to obtain a premixed resin material;

[0014] S2: Preparation of interface-modified filler: Adding the gradient interface enhancer and the nano-composite filler to the premixed resin material, and dispersing and stirring to obtain an interface-modified filler;

[0015] S3: Two-stage extrusion: At a temperature of 120 - 130 °C, rotate and mix the interfacial modified filler at a speed of 200 - 250 rpm, then add the low-temperature toughening network agent and the amine / nano-titanium dioxide composite anti-aging agent, and rotate and mix at a temperature of 100 - 110 °C and a speed of 150 - 190 rpm to obtain a melt strip;

[0016] S4: Pelletizing and forming: Cut the melt strip into pellets under running water, and dehydrate and dry the cut pellets to obtain coating masterbatch with a diameter of 2 - 3 mm;

[0017] S5: Microcapsule pretreatment: Fuse the microcapsules and polyurethane powder, and screen and remove impurities from the fused material to obtain a premix;

[0018] S6: Injection molding: Heat and melt the coating masterbatch to obtain a coating fluid. At the same time, inject the premix at the front end of the coating fluid, and heat the premix and the coating fluid to 75 °C to obtain a hot-melt coating.

[0019] Furthermore, in step S2, put the premixed resin material into a reaction kettle, cool down to 92 - 98 °C, and then add the gradient interfacial enhancer and nano-composite filler at intervals, and set the interval time to 5 - 10 minutes.

[0020] Furthermore, in step S2, the premixed resin material, gradient interfacial enhancer and nano-composite filler are dispersed and stirred at a speed of 850 - 950 rpm.

[0021] Furthermore, in step S3, during the rotation mixing process in the first stage, 6 temperature zones are set, and the temperature of each temperature zone is set as follows: 119 - 121 °C, 124.5 - 125.5 °C, 127.7 - 128.3 °C, 129.8 - 130.2 °C, 127.7 - 128.3 °C and 124.5 - 125.5 °C;

[0022] During the rotation mixing process in the second stage, 4 temperature zones are set, and the temperature of each temperature zone is set as follows: 102 - 108 °C, 105 - 111 °C, 107 - 113 °C and 105 - 111 °C.

[0023] Furthermore, in step S5, before the microcapsules and polyurethane powder are fused, the following pretreatment is carried out:

[0024] S5.1: Put the ultrasonically cleaned microcapsules into an ethanol solution for soaking and stirring, and obtain pretreated microcapsules through centrifugal separation;

[0025] S5.2: After separating the polyurethane powder by particle size, perform plasma cleaning on the separated polyurethane powder to obtain pretreated polyurethane powder;

[0026] S5.3: Spray isomeric tridecyl alcohol polyoxyethylene ether on the surfaces of the pretreated microcapsules, pretreated polyurethane powder, and nano-silica anti-caking agent respectively, and stir at a rotation speed of 44 - 55 rpm to form a premixed slurry.

[0027] Furthermore, in step S6, during the heating process of the premix and the coating fluid, it is divided into three temperature zones, and the temperature of each temperature zone is set respectively as: 64 - 66 °C, 69.5 - 70.5 °C, and 74.7 - 75.3 °C.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] Firstly: Through the composite resin matrix, the material still maintains a high elongation at break at -30 °C. At the same time, through the gradient interface enhancer and nano-composite filler, an interface-modified filler is prepared, which not only enhances the interface bonding strength, but also prevents the agglomeration of the filler. At the same time, the coating masterbatch is combined with the dynamic self-healing agent, making it have dynamic self-healing ability and extending the service life;

[0030] Secondly: The present invention adds a low-temperature toughening network agent to the composite resin matrix, enabling it to maintain elasticity at low temperatures through a dynamic crosslinked network and reducing stress concentration;

[0031] Thirdly: Through two-stage low-temperature extrusion in the present invention, that is, melting and mixing in the first stage and adding a toughening agent in the second stage, not only can the energy consumption be reduced, but also through gradient heating in different temperature zones, the uniform dispersion of components without decomposition can be ensured. Brief Description of the Drawings

[0032] Figure 1 It is the microscopic structure diagram of the high weather-resistant composite modified road hot-melt coating of the present invention;

[0033] Figure 2 It is the microscopic structure diagram of the hot-melt coating in Example 1 of the present invention;

[0034] Figure 3 It is the microscopic structure diagram of the hot-melt coating in Example 2 of the present invention;

[0035] Figure 4 It is the microscopic structure diagram of the hot-melt coating in Example 3 of the present invention;

[0036] Figure 5 It is the performance difference comparison diagram among the hot-melt coatings in Example 1, Example 2, and Example 3 of the present invention;

[0037] Figure 6 This is the material property comparison chart of the present invention. Detailed implementation manners

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0039] In the existing high weather resistance composite modified road hot melt coating, in a low temperature environment of -20°C, problems such as restricted movement of resin molecular chain segments, phase separation of elastomeric modifiers, and reduced interfacial bonding strength between fillers and resins will occur, resulting in a significant embrittlement phenomenon of the material. At the same time, under the cyclic stress of the dynamic rolling load of vehicles, stress concentration areas inside the coating film (such as defects like filler agglomerations and microvoids) will preferentially generate microcracks, and due to the low temperature environment severely inhibiting the plastic deformation and stress relaxation capabilities of the resin, the cracks will rapidly expand and penetrate each other, leading to the fatigue failure of the coating film within a cycle far lower than the designed service life. And in this embodiment, a high weather resistance composite modified road hot melt coating is provided, effectively solving the problems of low temperature embrittlement and early fatigue failure caused by dynamic loads.

[0040] Reference Figure 1 , this embodiment provides a high weather resistance composite modified road hot melt coating, which includes 35 - 50 parts of a composite resin matrix, 15 - 20 parts of a gradient interface enhancer, 18 - 25 parts of a nano composite filler, 8 - 12 parts of a low temperature toughening network agent, and 5 - 8 parts of a dynamic self - repairing agent. Among them, the composite resin matrix includes ethylene - vinyl acetate copolymer, hydrogenated styrene - isoprene - styrene block copolymer, and polyether - type polyurethane in a mass ratio of (20 - 25):(12 - 15):(8 - 10). The gradient interface enhancer includes epoxy groups, carboxyl groups, and zwitterionic groups in a mass ratio of 1:(0.33 - 0.79):(0.72 - 1.8). The nano composite filler includes component materials, silane coupling agent, and titanate coupling agent in a mass ratio of (7.2 - 16.7):1:(0.32 - 0.8).

[0041] Furthermore, the component materials include silica and aluminum oxide with a mass ratio of (2.7 - 3.3):1, and the spherical silica has a diameter of 50 - 100 nm, while the flaky aluminum oxide has a thickness of 20 - 50 nm. Further, silane coupling agent and titanate coupling agent cover the surface of the component materials, and the surface coverage thickness of the component materials is 3 - 8 nm. Meanwhile, the coverage rate of the silane coupling agent is 60 - 70%, and the coverage rate of the titanate coupling agent is 30 - 40%.

[0042] Reference Figure 6 , Figure 6 is the comparison chart of material properties in this embodiment. It can be seen from Figure 6 that: at the repair rate of 25°C / 24h, the traditional coating has no repair, while the repair rate of the hot-melt coating of this solution is not less than 85%. At the repair rate of -10°C / 48h, the traditional coating has no repair, while the repair rate of the hot-melt coating of this solution is not less than 70%. That is to say, in this embodiment, low-temperature toughness is provided by the composite resin matrix. At the same time, after strengthening the interface bonding with the gradient interface enhancer and nano-composite filler, it is integrated with the dynamic self-healing agent composed of microcapsules and polyurethane powder, enabling it to be rapidly repaired at room temperature and still effective in a low-temperature environment, thus overcoming the problems of low-temperature embrittlement, phase separation, and early failure caused by dynamic loads of traditional coatings.

[0043] Example 1

[0044] This embodiment provides a low-temperature preparation process for a highly weather-resistant composite modified road hot-melt coating. Using 40 parts of composite resin matrix, 18 parts of gradient interface enhancer, 21 parts of nano-composite filler, 10 parts of low-temperature toughening network agent, and 7 parts of dynamic self-healing agent as raw materials to prepare a highly weather-resistant composite modified road hot-melt coating. At the same time, the composite resin matrix includes ethylene-vinyl acetate copolymer, hydrogenated styrene-isoprene-styrene block copolymer, and polyether-type polyurethane with a mass ratio of 22:13:9. The gradient interface enhancer includes epoxy group, carboxyl group, and zwitterionic group with a mass ratio of 1:0.55:1.35. The nano-composite filler includes component materials, silane coupling agent, and titanate coupling agent with a mass ratio of 11.5:1:0.55. At the same time, the component materials include silica and aluminum oxide with a mass ratio of 3:1. The low-temperature preparation process includes the following steps:

[0045] Step S1: Premixing of matrix materials. That is, putting ethylene-vinyl acetate copolymer and hydrogenated styrene-isoprene-styrene block copolymer into a kneader, and kneading for 8 minutes at a temperature of 115°C and a rotation speed of 80 rpm.

[0046] Furthermore, after raising the temperature to 130°C, nitrogen gas is introduced into the internal mixer at a rate of 5 L / min. Meanwhile, polyether-type polyurethane particles are added to the internal mixer, and mixing is continued at a rotational speed of 135 rpm to obtain a premixed resin material.

[0047] Step S2: Prepare an interface-modified filler. That is, the premixed resin material is placed in a reaction kettle and cooled with cooling water. After the premixed resin material is cooled to 95°C, a gradient interface enhancer is first added to the cooled premixed resin material, and it is stirred at a rotational speed of 900 rpm in a high-speed disperser for 5 minutes. Then, a nano-composite filler is added, and stirring is continued at a rotational speed of 900 rpm to obtain an interface-modified filler.

[0048] Step S3: Two-stage extrusion. That is, through a loss-in-weight feeder, the interface-modified filler is input into the feed inlet of the first-stage extruder of a twin-screw extruder at a rate of 20 kg / h. Meanwhile, the temperatures of the 6 temperature zones of the first-stage extruder are respectively set to: 120°C, 125°C, 128°C, 130°C, 128°C, and 125°C, and the temperature is increased at a rate of 3°C / min. At the same time, the first-stage screw rotates and mixes the interface-modified filler at a rotational speed of 230 rpm and conveys it to the feed inlet of the second-stage extruder.

[0049] Furthermore, the temperatures of the 4 temperature zones of the second-stage extruder are respectively set to: 105°C, 107°C, 110°C, and 107°C. At three temperature zones, a low-temperature toughening network agent is added through a side feeder, and a hindered amine / nano-titanium dioxide composite anti-aging agent is injected through a high-pressure liquid injection pump. After rotational mixing at a rotational speed of 170 rpm, a uniform melt strip is formed through a porous die head.

[0050] Step S4: Pelletizing and forming. That is, a rotary cutter cuts the melt strip at a rate of 3000 rpm under the circulation of cooling water to obtain particles with a size of 3 mm in length. Furthermore, the cut particles are placed in a centrifugal dehydrator and centrifugally dehydrated at a rotational speed of 2500 rpm. At the same time, drying treatment is carried out through a fluidized bed dryer at a temperature of 50°C to obtain a coating masterbatch with a diameter of 3 mm.

[0051] Step S5: Microcapsule pretreatment. That is, after putting polyurethane powder into a three-dimensional mixer, microcapsules are slowly added into the three-dimensional mixer, and fumed silica is added as a flow aid, and mixing is carried out at a rotational speed of 20 rpm for 30 minutes. Furthermore, the fused material is sieved and impurities are removed through a sieve with a size of 38 μm and a quantity of 400 meshes to obtain a premixed material.

[0052] In this embodiment, before the microcapsules and the polyurethane powder are fused, the following pretreatment is carried out, including the following steps:

[0053] Step S5.1: Using absolute ethanol as a solvent, clean the microcapsules with an ultrasonic cleaner for 10 minutes. Meanwhile, put the cleaned microcapsules into an ethanol solution and stir them at a temperature of 60°C and a rotation speed of 200 rpm for 30 minutes. Further, centrifuge the microcapsules at a rotation speed of 3000 rpm for 5 minutes, and then vacuum dry them at a temperature of 60°C for 2 hours to obtain pretreated microcapsules.

[0054] Step S5.2: Separate the particle size of the polyurethane powder through an air classifier to obtain polyurethane powder with a size of 15 μm. Further, clean the separated polyurethane powder with a plasma cleaner for 90 seconds to obtain pretreated polyurethane powder.

[0055] Step S5.3: Spray isomeric tridecyl polyoxyethylene ether on the surfaces of the pretreated microcapsules, pretreated polyurethane powder, and nano-silica anti-caking agent respectively, and stir them at a rotation speed of 50 rpm for 5 minutes to form a premixed slurry.

[0056] Step S6: Injection molding. That is, convey the coating masterbatch to the barrel of the injection machine through a screw, and heat and melt it in three temperature zones of 65°C, 70°C, and 75°C to obtain a coating fluid. Further, inject the premixed material through a side feeder at the front end of the coating fluid. The premixed material and the polyurethane matrix in the coating fluid exhibit co-crystallization to form an interpenetrating network. At the same time, the screw rotates at a rate of 180 rpm to generate a shear rate of 90 s -1 to obtain a hot-melt coating. In this embodiment, the mass ratio between the coating masterbatch and the premixed material is set to 85:15.

[0057] Reference Figure 2 , Figure 2 is the microstructural diagram of the hot-melt coating obtained in the first embodiment of this example.

[0058] Example 2

[0059] This embodiment provides a low-temperature preparation process for a highly weather-resistant composite modified road hot-melt coating. Using 35 parts of composite resin matrix, 15 parts of gradient interface enhancer, 18 parts of nano-composite filler, 8 parts of low-temperature toughening network agent and 5 parts of dynamic self-healing agent as raw materials to prepare a highly weather-resistant composite modified road hot-melt coating. At the same time, the composite resin matrix includes ethylene-vinyl acetate copolymer, hydrogenated styrene-isoprene-styrene block copolymer and polyether-type polyurethane in a mass ratio of 20:12:8, the gradient interface enhancer includes epoxy group, carboxyl group and zwitterionic group in a mass ratio of 1:0.33:0.72, and the nano-composite filler includes component materials, silane coupling agent and titanate coupling agent in a mass ratio of 7.2:1:0.32. At the same time, the component materials include silica and alumina in a mass ratio of 2.7:1. The low-temperature preparation process includes the following steps:

[0060] Step S1: Premixing of matrix materials. That is, put ethylene-vinyl acetate copolymer and hydrogenated styrene-isoprene-styrene block copolymer into a kneader, and knead for 10 minutes at a temperature of 112 °C and a rotation speed of 78 rpm.

[0061] Furthermore, after raising the temperature to 132 °C, introduce nitrogen into the kneader at a rate of 4 L / min, and at the same time add polyether-type polyurethane particles into the kneader, and continue to knead at a rotation speed of 138 rpm to obtain a premixed resin material.

[0062] Step S2: Preparation of interface-modified filler. That is, put the premixed resin material into a reaction kettle, and cool it down with cooling water. After the premixed resin material is cooled down to 90 °C, first add the gradient interface enhancer to the cooled premixed resin material, and stir at a rotation speed of 950 rpm in a high-speed disperser for 4 minutes, then add the nano-composite filler, and continue to stir at a rotation speed of 950 rpm to obtain an interface-modified filler.

[0063] Step S3: Two-stage extrusion. That is, through a loss-in-weight feeder, input the interface-modified filler into the feed port of the first-stage extruder of a two-stage screw extruder at a rate of 20 kg / h. At the same time, set the temperatures of the 6 temperature zones of the first-stage extruder to 119 °C, 124.5 °C, 127.7 °C, 129.8 °C, 127.7 °C and 124.5 °C respectively, and raise the temperature at a rate of 3 °C / min. At the same time, the first-stage screw rotates and mixes the interface-modified filler at a rotation speed of 232 rpm, and conveys it to the feed port of the second-stage extruder.

[0064] Furthermore, the temperatures of the four temperature zones of the second-stage extruder are set to 102 °C, 105 °C, 107 °C, and 105 °C respectively. And at three temperature zones, a low-temperature toughening network agent is added through a side feeder, and at the same time, an amine blocker / nano-titanium dioxide composite anti-aging agent is injected through a high-pressure liquid injection pump. After rotating and mixing at a speed of 172 rpm, a uniform melt strip is formed through a porous die head.

[0065] Step S4: Pelletizing and forming. That is, a rotary cutter cuts the melt strip at a rate of 3000 rpm under the circulation of cooling water to obtain particles with a size of 2.5 mm in length. Further, the cut particles are put into a centrifugal dehydrator and centrifugally dehydrated at a speed of 2500 rpm. At the same time, drying treatment is carried out through a fluidized bed dryer at a temperature of 50 °C to obtain coating masterbatch with a diameter of 2.5 mm.

[0066] Step S5: Microcapsule pretreatment. That is, after putting polyurethane powder into a three-dimensional mixer, microcapsules are slowly added into the three-dimensional mixer, and fumed silica is added as a flow aid, and mixed at a speed of 20 rpm for 30 minutes. Further, the fused material is sieved and decontaminated through a sieve with a size of 38 μm and a quantity of 400 meshes to obtain a premix.

[0067] In this embodiment, before the microcapsules and the polyurethane powder are fused, the following pretreatment is carried out, including the following steps:

[0068] Step S5.1: Using anhydrous ethanol as a solvent, the microcapsules are cleaned by an ultrasonic cleaner for 10 minutes. At the same time, the cleaned microcapsules are put into an ethanol solution and stirred at a temperature of 60 °C and a speed of 200 rpm for 30 minutes. Further, the microcapsules are centrifuged at a speed of 3000 rpm for 5 minutes and vacuum dried at a temperature of 60 °C for 2 hours to obtain pretreated microcapsules.

[0069] Step S5.2: The polyurethane powder is separated by particle size through an air classifier to obtain polyurethane powder with a size of 15 μm. Further, the separated polyurethane powder is cleaned by a plasma cleaner for 90 seconds to obtain pretreated polyurethane powder.

[0070] Step S5.3: Isotridecyl polyoxyethylene ether is sprayed on the surfaces of the pretreated microcapsules, the pretreated polyurethane powder, and the nano-silica anti-caking agent respectively, and stirred at a speed of 50 rpm for 5 minutes to form a premixed slurry.

[0071] Step S6: Injection molding. That is, the coating masterbatch is conveyed to the barrel of the injection machine through a screw, and is heated and melted in three temperature gradients of 64 °C, 69.5 °C and 74.7 °C to obtain a coating fluid. Further, at the front end of the coating fluid, the premix is injected through a side feeder, and the premix and the polyurethane matrix in the coating fluid undergo co-crystallization to form an interpenetrating network. At the same time, the screw rotates at a rate of 180 rpm to generate a shear rate of 90 s -1 to obtain a hot-melt coating. In this embodiment, the mass ratio between the coating masterbatch and the premix is set to 85:15.

[0072] Reference Figure 3 , Figure 3 is the microstructural diagram of the hot-melt coating obtained in the second embodiment of the present invention.

[0073] Example 3

[0074] This embodiment provides a low-temperature preparation process for a highly weather-resistant composite modified road hot-melt coating. Using 50 parts of a composite resin matrix, 20 parts of a gradient interface enhancer, 25 parts of a nano-composite filler, 12 parts of a low-temperature toughening network agent, and 8 parts of a dynamic self-healing agent as raw materials to prepare a highly weather-resistant composite modified road hot-melt coating. At the same time, the composite resin matrix includes ethylene-vinyl acetate copolymer, hydrogenated styrene-isoprene-styrene block copolymer, and polyether-type polyurethane in a mass ratio of 25:15:10. The gradient interface enhancer includes epoxy groups, carboxyl groups, and zwitterionic groups in a mass ratio of 1:0.79:1.8. The nano-composite filler includes component materials, silane coupling agent, and titanate coupling agent in a mass ratio of 16.7:1:0.8. At the same time, the component materials include silica and aluminum oxide in a mass ratio of 3.3:1. The low-temperature preparation process includes the following steps:

[0075] Step S1: Premixing of matrix materials. That is, the ethylene-vinyl acetate copolymer and the hydrogenated styrene-isoprene-styrene block copolymer are put into a kneader, and kneaded for 10 minutes at a temperature of 112 °C and a rotation speed of 78 rpm.

[0076] Further, after the temperature is raised to 132 °C, nitrogen is introduced into the kneader at a rate of 4 L / min, and at the same time, polyether-type polyurethane particles are added to the kneader, and kneading is continued at a rotation speed of 138 rpm to obtain a premixed resin material.

[0077] Step S2: Prepare the interface-modified filler. That is, put the premixed resin material into a reaction kettle and cool it down with cooling water. After the premixed resin material is cooled down to 90 °C, first add a gradient interface enhancer to the cooled premixed resin material, and stir it at a speed of 950 rpm in a high-speed disperser for 4 minutes. Then add the nano-composite filler and continue to stir at a speed of 950 rpm to obtain the interface-modified filler.

[0078] Step S3: Two-stage extrusion. That is, through a loss-in-weight feeder, input the interface-modified filler into the feeding port of the first-stage extruder of a two-stage screw extruder at a rate of 20 kg / h. At the same time, set the temperatures of the 6 temperature zones of the first-stage extruder to 121 °C, 125.5 °C, 128.3 °C, 130.2 °C, 128.3 °C, and 125.5 °C respectively, and increase the temperature at a rate of 3 °C / min. At the same time, the first-stage screw rotates and mixes the interface-modified filler at a speed of 232 rpm and conveys it to the feeding port of the second-stage extruder.

[0079] Furthermore, set the temperatures of the 4 temperature zones of the second-stage extruder to 108 °C, 111 °C, 113 °C, and 111 °C respectively. At three temperature zones, add a low-temperature toughening network agent through a side feeder, and at the same time inject an amine / nano-titanium dioxide composite anti-aging agent through a high-pressure liquid injection pump. After rotating and mixing at a speed of 172 rpm, form a uniform melt strip through a porous die head.

[0080] Step S4: Pelletizing and forming. That is, the rotary cutter cuts the melt strip at a rate of 3000 rpm under the circulation of cooling water to obtain particles with a length of 2.5 mm. Furthermore, put the cut particles into a centrifugal dehydrator and perform centrifugal dehydration at a speed of 2500 rpm. At the same time, perform drying treatment through a fluidized bed dryer at a temperature of 50 °C to obtain coating masterbatch with a diameter of 2.5 mm.

[0081] Step S5: Microcapsule pretreatment. That is, put the polyurethane powder into a three-dimensional mixer, then slowly add microcapsules into the three-dimensional mixer, and add fumed silica as a flow aid, and mix at a speed of 20 rpm for 30 minutes. Furthermore, screen and remove impurities from the fused material through a sieve with a size of 38 μm and a quantity of 400 meshes to obtain the premixed material.

[0082] In this embodiment, before the microcapsules and the polyurethane powder are fused, the following pretreatment is carried out, including the following steps:

[0083] Step S5.1: Using absolute ethanol as the solvent, clean the microcapsules with an ultrasonic cleaner for 10 minutes. Meanwhile, place the cleaned microcapsules into an ethanol solution and stir for 30 minutes at a temperature of 60°C and a rotation speed of 200 rpm. Further, centrifuge the microcapsules at a rotation speed of 3000 rpm for 5 minutes, and then vacuum dry them at a temperature of 60°C for 2 hours to obtain pretreated microcapsules.

[0084] Step S5.2: Separate the particle size of the polyurethane powder through an air classifier to obtain polyurethane powder with a size of 15 μm. Further, clean the separated polyurethane powder with a plasma cleaner for 90 seconds to obtain pretreated polyurethane powder.

[0085] Step S5.3: Spray isomeric tridecyl polyoxyethylene ether on the surfaces of the pretreated microcapsules, pretreated polyurethane powder, and nano-silica anti-caking agent respectively, and stir at a rotation speed of 50 rpm for 5 minutes to form a premixed slurry.

[0086] Step S6: Injection molding. That is, convey the coating masterbatch to the barrel of the injection machine through a screw, and heat and melt it in three temperature zones of 66°C, 70.5°C, and 75.3°C to obtain a coating fluid. Further, inject the premixed material through a side feeder at the front end of the coating fluid. The premixed material and the polyurethane matrix in the coating fluid exhibit co-crystallization to form an interpenetrating network. At the same time, the screw rotates at a rate of 180 rpm to generate a shear rate of 90 s -1 to obtain a hot-melt coating. In this embodiment, the mass ratio between the coating masterbatch and the premixed material is set to 85:15.

[0087] Reference Figure 4 , Figure 4 is the microstructural diagram of the hot-melt coating obtained in the third embodiment of this example.

[0088] Reference Figure 5 , Figure 5 is the performance difference comparison chart among the hot-melt coatings in the first embodiment, the second embodiment, and the third embodiment. It can be seen from the figure that in the third embodiment, the proportion of the composite resin matrix is set to 25:15:10, the proportion of the component materials is set to 3.3:1, and the dynamic self-healing agent is set to 8 parts, making it perform optimally in terms of low-temperature toughness (the elongation at break at -30°C is increased by 15%), interfacial strength (the shear strength reaches 15 MPa), and self-healing efficiency (the repair rate is 85%). However, its raw material cost increases by 22%, and at the same time, its process control requirements are also more stringent, with a temperature control accuracy of ±0.5°C.

[0089] Furthermore, the material settings in Example 1 achieved a balance between performance and cost. The composite resin matrix ratio of 22:13:9 and the component material ratio of 3:1 are suitable for road markings in most temperate regions.

[0090] Furthermore, in Example 2, the dosages of the composite resin matrix and the dynamic self-healing agent were reduced, resulting in a decrease in its low-temperature performance compared to the hot-melt coatings obtained in Example 1 and Example 3. Specifically, the elastic modulus decreased by 10%. However, this led to a 14% cost savings and an increase in the qualified rate to 95%.

[0091] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended embodiments and their equivalents.

Claims

1. A high weather resistance composite modified hot melt road coating, characterized in that, It includes 35 - 50 parts of composite resin matrix, 15 - 20 parts of gradient interface enhancer, 18 - 25 parts of nano - composite filler, 8 - 12 parts of low - temperature toughening network agent and 5 - 8 parts of dynamic self - repairing agent.

2. The high weather resistance composite modified hot melt road coating according to claim 1, characterized in that, The composite resin matrix includes ethylene - vinyl acetate copolymer, hydrogenated styrene - isoprene - styrene block copolymer and polyether - type polyurethane in a mass ratio of (20 - 25):(12 - 15):(8 - 10); The gradient interface enhancer includes epoxy group, carboxyl group and zwitterionic group in a mass ratio of 1:(0.33 - 0.79):(0.72 - 1.8); The nano - composite filler includes component materials, silane coupling agent and titanate coupling agent in a mass ratio of (7.2 - 16.7):1:(0.32 - 0.8).

3. A highly weather-resistant composite modified road hot-melt coating according to claim 2, characterized in that, The component materials include silica and aluminum oxide in a mass ratio of (2.7 - 3.3):

1. Meanwhile, the diameter of spherical silica is 50 - 100 nm, and the thickness of flaky aluminum oxide is 20 - 50 nm.

4. The high weather resistance composite modified hot melt road coating according to claim 2, characterized in that The silane coupling agent and titanate coupling agent cover the surface of the component materials, and the surface coverage thickness of the component materials is 3 - 8 nm. Meanwhile, the coverage rate of the silane coupling agent is 60 - 70%, and the coverage rate of the titanate coupling agent is 30 - 40%.

5. A low-temperature preparation process for a highly weather-resistant composite modified hot-melt road coating, characterized in that, To prepare a highly weather - resistant composite - modified road hot - melt coating as described in any one of claims 1 - 4, the following steps are included: S1: Premixing of matrix materials: Melt - mix ethylene - vinyl acetate copolymer and hydrogenated styrene - isoprene - styrene block copolymer, and after mixing, add polyether - type polyurethane particles to obtain a premixed resin material; S2: Preparation of interface - modified filler: Add the gradient interface enhancer and nano - composite filler to the premixed resin material, and disperse and stir to obtain an interface - modified filler; S3: Two - stage extrusion: At a temperature of 120 - 130 °C, rotate and mix the interface - modified filler at a speed of 200 - 250 rpm, then add the low - temperature toughening network agent and hindered amine / nano - titanium dioxide composite anti - aging agent, and rotate and mix at a temperature of 100 - 110 °C and a speed of 150 - 190 rpm to obtain a melt strip; S4: Pelletizing and forming: Pelletize the melt strip under running water, and dehydrate and dry the pelletized particles to obtain coating masterbatch with a diameter of 2 - 3 mm; S5: Micro - capsule pretreatment: Fuse micro - capsules and polyurethane powder, and screen and remove impurities from the fused material to obtain a premixed material; S6: Injection molding: Heat - melt the coating masterbatch to obtain a coating fluid. Meanwhile, inject the premixed material at the front end of the coating fluid, and heat the premixed material and the coating fluid to 75 °C to obtain a hot - melt coating.

6. The low-temperature preparation process of a highly weather-resistant composite modified road hot-melt coating according to claim 5, characterized in that, In step S2, put the premixed resin material into a reaction kettle, cool it down to 92 - 98 °C, and then add the gradient interface enhancer and nano - composite filler at intervals, and set the interval time to 5 - 10 minutes.

7. The low-temperature preparation process of a highly weather-resistant composite modified road hot-melt coating according to claim 5 or 6, characterized in that, In step S2, the premixed resin material, the gradient interface enhancer, and the nano-composite filler are dispersively stirred at a rotation speed of 850 - 950 rpm.

8. The low-temperature preparation process of a highly weather-resistant composite modified road hot-melt coating according to claim 5, characterized in that In step S3, during the rotational mixing process in the first stage, 6 temperature zones are set, and the temperature of each temperature zone is respectively set to: 119 - 121 °C, 124.5 - 125.5 °C, 127.7 - 128.3 °C, 129.8 - 130.2 °C, 127.7 - 128.3 °C, and 124.5 - 125.5 °C; In the rotational mixing process in the second stage, 4 temperature zones are set, and the temperature of each temperature zone is respectively set to: 102 - 108 °C, 105 - 111 °C, 107 - 113 °C, and 105 - 111 °C.

9. The low-temperature preparation process of a highly weather-resistant composite modified road hot-melt coating according to claim 5, characterized in that In step S5, before the microcapsules and the polyurethane powder are fused, the following pretreatment is carried out: S5.1: The ultrasonically cleaned microcapsules are put into an ethanol solution for soaking and stirring, and after centrifugal separation, pretreated microcapsules are obtained; S5.2: After the polyurethane powder is separated by particle size, the separated polyurethane powder is subjected to plasma cleaning to obtain pretreated polyurethane powder; S5.3: Isotridecyl polyoxyethylene ether is respectively sprayed on the surfaces of the pretreated microcapsules, the pretreated polyurethane powder, and the nano-silica anti-caking agent, and stirring is carried out at a rotation speed of 44 - 55 rpm to form a premixed slurry.

10. The low-temperature preparation process of a highly weather-resistant composite modified road hot-melt coating according to claim 5, characterized in that, In step S6, during the heating process of the premix and the coating fluid, it is divided into three temperature zones, and the temperature of each temperature zone is respectively set to: 64 - 66 °C, 69.5 - 70.5 °C, and 74.7 - 75.3 °C.

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