Microcapsules, methods of making and using the same

Abstract

The application discloses a kind of microcapsules and its preparation method and application.The microcapsule includes capsule core and capsule wall, capsule core is wrapped in capsule wall, capsule core contains active component, the elastic modulus of microcapsule and the thickness of capsule wall satisfy the following formula: Y=0.42X 2 -0.92X+T, wherein Y is the elastic modulus of microcapsule, unit is GPa;X is the thickness of capsule wall, unit is μm;T is 1±0.1;The elastic modulus of microcapsule is obtained by mechanical property testing of microcapsule using nanoindentation instrument, the thickness of capsule wall is obtained by testing microcapsule frozen section using scanning electron microscope.The microcapsule of the application is suitable for road asphalt, can effectively improve the self-repair efficiency of road asphalt material;And in the process of asphalt construction, it can effectively reduce the emission of asphalt fume, reduce the pollution to environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microcapsule materials, in particular to a microcapsule, a preparation method and application thereof, more particularly to a microcapsule, a preparation method thereof and application of the microcapsule in asphalt pavement. BACKGROUND

[0002] During the use of asphalt pavement, microcracks and local damages are prone to occur inside due to vehicle load and environmental factors. If not controlled in time, the microcracks will expand under the action of external load, leading to the formation of macrocracks. Water seepage at the cracks will further aggravate the damage to the pavement structure, so that the road cannot reach the designed service life. Since the microcracks of asphalt pavement often occur inside, it is difficult to discover such micro-damages in time, and it is almost impossible to repair them manually, so that the repair of initial cracks is difficult to achieve, and serious cracks may cause macrocracks and structural failure. The current repair methods only take remedial measures after obvious cracks appear on the pavement. Although such repair can solve the existing problems, it will inevitably affect the traffic and cause multiple losses of manpower and material resources.

[0003] By using the microcapsule technology, the repairing agent is coated in the microcapsule, and the automatic repair of pavement cracks can be achieved after the microcapsule is added to asphalt. When asphalt produces microcracks due to aging or load, the microcapsule at the crack path will break due to the expansion of the tip stress; the repairing agent is released from the microcapsule wall material and flows along the microcrack and penetrates and diffuses to both sides of the microcrack under the push of capillary action, so that the microcrack gradually disappears, and finally the self-repairing effect of asphalt is achieved. During the use of asphalt pavement, the microcapsule should have sufficient strength to avoid breaking during the mixing of asphalt mixture, but if the strength of the microcapsule is too large, the crack will easily expand forward by bypassing the microcapsule when the microcrack appears on the asphalt pavement, so that the microcapsule is difficult to break and cannot play its repairing role.

[0004] Chinese Patent Application CN104231642A discloses an asphalt crack self-repairing microcapsule containing a regenerating agent and a preparation method thereof. The microcapsule is prepared by using polyurea formaldehyde resin as the wall material and asphalt regenerating agent as the core material, and can enhance the self-repairing ability of asphalt pavement to a certain extent, but the combination of the microcapsule and asphalt is not tight enough, and the microcapsule is prone to break, which affects the self-repairing efficiency of the microcapsule.

[0005] In summary, the prior art does not consider the bonding strength of the microcapsule and asphalt, but simply adds the microcapsule to the asphalt, so that the microcapsule and asphalt cannot be effectively integrated, and the microcapsule is prone to separate from the asphalt, further aggravating the phenomenon that the microcapsule is difficult to break.

[0006] In addition, as the main type of highway, the asphalt pavement still uses the traditional hot-mixing and hot-paving process in the construction process. In the construction process, the asphalt will contact with oxygen in the air and react: on the one hand, the condensation reaction generates large molecular weight condensed aromatics, which further condenses into colloid and asphaltene; on the other hand, the asphalt molecules will crack under the condition of heat to generate smaller molecular weight compounds, which volatilize to form asphalt fume, seriously damaging the ecological balance, polluting the surrounding environment and harming human health.

[0007] In view of the unorganized release of volatile organic compounds (VOCs) in the paving process of asphalt pavement, it is difficult to collect and manage the whole process, and it is urgent to solve the problem of how to reduce the release of asphalt fume at the source and realize clean construction of asphalt pavement to ensure the harmonious development of the transportation industry and social economy. SUMMARY

[0008] The purpose of the present application is to overcome the problem that the microcapsule material cannot be effectively fused with asphalt after being added to asphalt, so that the microcapsule is easily separated from asphalt, and to provide a new microcapsule and its preparation method and application. The microcapsule described in the present application not only has high strength, which meets the requirements of pavement use, but also has good bonding strength with asphalt.

[0009] To achieve the above purpose, the present application provides a microcapsule, which comprises a capsule core and a capsule wall, the capsule core is wrapped in the capsule wall, the capsule core contains an active component, and the elastic modulus of the microcapsule and the thickness of the capsule wall satisfy the following formula:

[0010] Y = 0.42X 2 -0.92X + T

[0011] Wherein, Y is the elastic modulus of the microcapsule, unit: GPa; X is the thickness of the capsule wall, unit: μm; T is 1 ± 0.1;

[0012] The elastic modulus of the microcapsule is obtained by mechanical property test of the microcapsule by nanoindentation instrument, and the thickness of the capsule wall is obtained by test of the microcapsule frozen section by scanning electron microscope.

[0013] Preferably, the content of the capsule core is 27-53 wt.%, and the content of the capsule wall is 47-73 wt.%, based on the total weight of the microcapsule.

[0014] Preferably, the active component is a repairing agent for self-repairing of pavement cracks and / or an inhibitor for inhibiting the release of asphalt fume.

[0015] Preferably, the repairing agent for self-repairing of pavement cracks is a rich aromatic component.

[0016] Preferably, the aromatic hydrocarbon-rich component is selected from at least one of catalytically cracked slurry oil, vacuum gas oil, furfural extract oil, and used lubricating oil.

[0017] Preferably, the aromatic hydrocarbon-rich component has an aromatic hydrocarbon content of 45 to 65 wt.%.

[0018] Preferably, the suppressor for suppressing release of asphalt fume gas is at least one of an aldehyde compound, a ketone compound, an alcohol compound, a phenol compound, and an ester compound.

[0019] Preferably, the aldehyde compound is at least one of a fatty aldehyde having a carbon number of 7 or more and an aromatic aldehyde having a carbon number of 6 or more, more preferably at least one of p-methylbenzaldehyde, decanal, o-carboxybenzaldehyde, p-isopropylbenzaldehyde, cinnamyl aldehyde, p-hydroxybenzaldehyde, p-methoxybenzaldehyde, 2-methyl-3-(3,4-methylene-dioxyphenyl)propanal, 3,4-methylenedioxybenzaldehyde, 3-(4-isopropylphenyl)-2-methylpropanal, ethyl vanillin, phenylacetaldehyde, anisic aldehyde, nonadiene-2,6-aldehyde, 2,6-dimethyl-2,6-octadienal, vanillin, citronellal, nerol, hydroxymethylamylcyclohexene acetal, p-diethylaminobenzaldehyde, and undecenal.

[0020] Preferably, the ketone compound is at least one of a fatty ketone having a carbon number of 8 or more and an aromatic ketone having a carbon number of 8 or more, more preferably at least one of 6-methyl-3,5-heptadien-2-one, 2-undecanone, acetophenone, ionone, methylionone, damascone, and dihydrodamascone.

[0021] Preferably, the alcohol compound is an alcohol having a carbon number of more than 6, more preferably at least one of cinnamyl alcohol, menthol, cis-3,7-dimethyl-2,6-octadienol, citronellol, geraniol, myrcenol, 2,6,10-trimethyl-2,6,10-dodecatrien-12-ol, lavandulol, benzyl alcohol, 2-phenylethanol, dihydromycenol, tetrahydrolinalool, and nerolidol.

[0022] Preferably, the phenol compound is a phenol having a carbon number of 6 or more, more preferably at least one of thymol, ethyl maltol, methyl maltol, 3-propenyl-6-ethoxyphenol, and isoeugenol.

[0023] Preferably, the ester compound is at least one of methyl salicylate, methyl cinnamate, ethyl cinnamate, ethyl phenylacetate, methyl phenylacetate, geranyl phenylacetate, phenethyl phenylacetate, isoamyl phenylacetate, benzyl salicylate, p-methylbenzyl acetate, benzyl acetate, isobutyl benzoate, isoamyl salicylate, benzyl laurate, phenethyl laurate, linalyl formate, linalyl acetate, linalyl isobutyrate, menthyl acetate, terpinyl acetate, and bornyl acetate.

[0024] Preferably, the thickness of the capsule wall is 0.5-5 μm.

[0025] Preferably, the capsule wall comprises an inner layer and an outer layer, the inner layer being a resin and the outer layer being a rubber material.

[0026] Preferably, the mass ratio of the inner layer to the outer layer is 2.4-5:1.

[0027] Preferably, the resin is at least one of melamine resin, urea-formaldehyde resin, and polymethyl methacrylate, and is preferably melamine resin.

[0028] Preferably, the rubber material is at least one of chlorinated rubber, styrene-butadiene rubber, and neoprene.

[0029] Preferably, the size of the microcapsule is 50 μm or less, preferably 20 μm or less, and more preferably 3-15 μm.

[0030] The second aspect of the present application provides a method for preparing a microcapsule, the method comprising:

[0031] (1) mixing an active component, an emulsifier, and water to form an oil-in-water emulsion;

[0032] (2) reacting the oil-in-water emulsion with a resin prepolymer, and then filtering, washing, and drying to obtain a pre-coated material;

[0033] (3) mixing a rubber material with the pre-coated material in the presence of a volatile solvent, and then mixing the obtained mixture with water, and heating to volatilize the volatile solvent to obtain a microcapsule.

[0034] Preferably, in step (1), the mass ratio of the active component, the emulsifier, and water is 1:(0.05-0.09):(6-9).

[0035] Preferably, in step (2), the pH value of the oil-in-water emulsion is adjusted to 5 or less, preferably 2-4, before the oil-in-water emulsion is reacted with the resin prepolymer.

[0036] Preferably, in step (2), the resin prepolymer is a melamine resin prepolymer.

[0037] Preferably, the preparation method of the melamine resin prepolymer comprises: mixing and dissolving melamine and formaldehyde solution with water, adjusting the pH value to 7.5-9.5, and then placing in a constant temperature water bath at 60-90℃, and reacting for 0.5-3.5h under stirring.

[0038] Preferably, the concentration of the formaldehyde solution is 30-40wt.%.

[0039] Preferably, the mass ratio of the amount of the melamine, the formaldehyde solution and water is 1:(2-3):(8-10).

[0040] Preferably, in step (3), the mass ratio of the amount of the rubber material, the volatile solvent and water is 1:(10-20):(50-150).

[0041] Preferably, the active component is one or at least two or more arbitrary combinations of aromatic hydrocarbon component, aldehyde compound, ketone compound, alcohol compound, phenolic compound and ester compound.

[0042] Preferably, the rubber material is at least one of chlorinated rubber, styrene butadiene rubber and chloroprene rubber.

[0043] Preferably, the emulsifier is at least one of sodium naphthenate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, cetyl trimethyl ammonium chloride, cetyl trimethyl ammonium bromide, cetyl dimethyl hydroxyethyl ammonium chloride, nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether and cetyl polyoxyethylene ether.

[0044] Preferably, the volatile solvent is at least one of carbon tetrachloride, dichloromethane and trichloroethylene.

[0045] The third aspect of the present application provides a microcapsule prepared by the above method.

[0046] The fourth aspect of the present application provides the use of the above microcapsule in road asphalt.

[0047] According to the microcapsule of the present application, the elastic modulus of the microcapsule and the thickness of the capsule wall satisfy a specific functional relationship, and in actual application, the elastic modulus of the microcapsule can be controlled within a required parameter range by adjusting the thickness of the capsule wall.

[0048] In a more preferred embodiment, the active component in the capsule core is selected as a repairing agent for repairing cracks on road surface, and the capsule wall comprises an inner layer and an outer layer, the inner layer is resin, and the outer layer is rubber material. The microcapsule of the preferred embodiment is particularly suitable for road asphalt, on the one hand, the microcapsule has a certain strength to meet the requirements of road surface use; on the other hand, the rubber material as the outer layer of the capsule wall can effectively fuse with asphalt, the rubber material has good adhesion and forms a strong bond with the resin (especially melamine resin) as the inner layer of the capsule wall, when cracks appear on the asphalt road surface, the probability of material rupture can be effectively improved, the outer layer of the capsule wall is torn to drive the inner layer of the capsule wall to be torn, the repairing agent is released, and the purpose of automatic repair is achieved. The two kinds of capsule wall materials can complement each other, thereby effectively improving the self-repairing efficiency of the road asphalt material.

[0049] In another more preferred embodiment, the active component in the capsule core is selected as an inhibitor for inhibiting the release of asphalt fume, and the capsule wall comprises an inner layer and an outer layer, the inner layer is resin, and the outer layer is rubber material. The microcapsule of the preferred embodiment is particularly suitable for road asphalt, the structure of the microcapsule can prolong the action time of the active component, so that the road asphalt has a longer storage and service life, and the emission of asphalt fume can be effectively reduced during the asphalt construction process, thereby reducing the pollution to the environment. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 SEM image of the microcapsule prepared in Example 1. DETAILED DESCRIPTION

[0051] The specific embodiments of the present application are described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and explanatory and are not intended to limit the present application.

[0052] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values and are understood to be encompassed within the range. For ranges with endpoints, the endpoints are included within the range. For ranges without endpoints, the range is understood to include values within the range. For numerical values, the endpoints are included within the range. For numerical ranges, the endpoints are included within the range, and the endpoints and individual points within the range can be combined to form one or more new ranges, which are to be considered as being specifically disclosed.

[0053] The microcapsule described in the present application comprises a capsule core and a capsule wall, the capsule core is wrapped in the capsule wall, the capsule core contains an active component, and the elastic modulus of the microcapsule and the thickness of the capsule wall satisfy the following formula:

[0054] Y = 0.42X 2 -0.92X + T

[0055] YX≤ 1 ± 0.1, wherein Y is the elastic modulus of the microcapsule, in GPa; X is the thickness of the capsule wall, in μm; and T is 1 ± 0.1.

[0056] The elastic modulus of the microcapsule is obtained by mechanical property testing of the microcapsule using a nanoindenter, and the thickness of the capsule wall is obtained by testing a frozen section of the microcapsule using a scanning electron microscope.

[0057] In the microcapsule of the present application, the thickness of the capsule wall can be 0.5-5 μm, and specifically, for example, can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2 μm, 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 3.6 μm, 3.7 μm, 3.8 μm, 3.9 μm, 4 μm, 4.1 μm, 4.2 μm, 4.3 μm, 4.4 μm, 4.5 μm, 4.6 μm, 4.7 μm, 4.8 μm, 4.9 μm, or 5 μm.

[0058] In some embodiments, the thickness of the capsule wall is 0.5-2 μm, and preferably 0.5-1.5 μm. The capsule wall of the microcapsule of this embodiment is thin, and the elastic modulus of the microcapsule is small, which is suitable for use in application scenarios requiring rapid release of the active component in the core.

[0059] In other embodiments, the thickness of the capsule wall is 2-3 μm. The capsule wall of the microcapsule of this embodiment is moderate, and the elastic modulus of the microcapsule is moderate, which is suitable for use in application scenarios requiring moderate speed release of the active component in the core.

[0060] In other embodiments, the thickness of the capsule wall is 3-5 μm. The capsule wall of the microcapsule of this embodiment is thick, and the elastic modulus of the microcapsule is large, which is suitable for use in application scenarios requiring slow release of the active component in the core.

[0061] In the microcapsule of the present application, the size of the microcapsule can be 50 μm or less, preferably 20 μm or less, and more preferably 3-15 μm.

[0062] In the microcapsule described in the present application, the content of the core can be 27-53 wt.%, and the content of the wall can be 47-73 wt.%, based on the total weight of the microcapsule. In some embodiments, the content of the core in the microcapsule can be 40-53 wt.%, and the content of the wall can be 47-60 wt.%; in other embodiments, the content of the core in the microcapsule can be 30-40 wt.%, and the content of the wall can be 60-70 wt.%; in still other embodiments, the content of the core in the microcapsule can be 27-30 wt.%, and the content of the wall can be 70-73 wt.%.

[0063] In the microcapsule described in the present application, the active component can be various conventional active components in sustained-release application scenarios. In some embodiments, the active component is a repairing agent for self-repairing of road surface cracks and / or an inhibitor for inhibiting release of asphalt fume. When the active component in the microcapsule is a repairing agent for self-repairing of road surface cracks, in the case of cracks in asphalt pavement, the probability of material rupture can be effectively increased, the outer wall layer is torn to drive the inner wall layer to tear, and the repairing agent is released, achieving the purpose of automatic repair. When the active component in the microcapsule is an inhibitor for inhibiting release of asphalt fume, the structure of the microcapsule can prolong the action time of the active component, so that the asphalt composition has a longer storage and service life, and can effectively reduce the emission of asphalt fume and reduce pollution to the environment during asphalt construction.

[0064] In the present application, the repairing agent for self-repairing of road surface cracks is preferably a rich aromatic component. The rich aromatic component refers to a material with an aromatic content of 40 wt.% or more. As a specific material selection, the rich aromatic component can be selected from at least one of catalytic cracking slurry oil, four-line reduced extraction oil, furfural extraction oil, and waste lubricating oil. In a preferred case, the aromatic content of the rich aromatic component is 45-65 wt.%, more preferably 50-60 wt.%, and further preferably 52-56 wt.%.

[0065] In the present application, the inhibitor for inhibiting release of asphalt fume is preferably at least one of an aldehyde compound, a ketone compound, an alcohol compound, a phenolic compound, and an ester compound.

[0066] In the present application, the aldehyde compound can be at least one of a fatty aldehyde having a carbon number of 7 or more and an aromatic aldehyde having a carbon number of 6 or more. In a preferred case, the aldehyde compound is at least one of a C7-C13 fatty aldehyde and a C6-C13 aromatic aldehyde. Specifically, the aldehyde compound is at least one selected from the group consisting of p-methylbenzaldehyde, decanal, o-carboxybenzaldehyde, p-isopropylbenzaldehyde, cinnamyl aldehyde, p-hydroxybenzaldehyde, p-methoxybenzaldehyde, 2-methyl-3-(3,4-methylene-dioxyphenyl)propanal, 3,4-methylenedioxybenzaldehyde, 3-(4-isopropylphenyl)-2-methylpropanal, ethyl vanillin, phenylacetaldehyde, nonadiene-2,6-aldehyde, 2,6-dimethyl-2,6-octadienal, vanillin, citronellal, neral, hydroxymethylpentylcyclohexene acetal, p-diethylaminobenzaldehyde, and undecenal.

[0067] In the present application, the ketone compound can be at least one of a fatty ketone having a carbon number of 8 or more and an aromatic ketone having a carbon number of 8 or more. In a preferred case, the ketone compound is at least one of a C8-C11 fatty ketone and a C8-C14 aromatic ketone. Specifically, the ketone compound is at least one selected from the group consisting of 6-methyl-3,5-heptadien-2-one, 2-undecanone, acetophenone, ionone, irone, methylionone, damascone, and dihydrodamascone.

[0068] In the present application, the alcohol compound is an alcohol having a carbon number of more than 6, and preferably a C7-C15 alcohol. Specifically, the alcohol compound is at least one selected from the group consisting of cinnamic alcohol, menthol, cis-3,7-dimethyl-2,6-octadienol, citronellol, geraniol, myrcenol, 2,6,10-trimethyl-2,6,10-dodecatrien-12-ol, lavandulol, benzyl alcohol, 2-phenylethanol, dihydromycenol, tetrahydrolinalool, and nerolidol.

[0069] In the present application, the phenol compound is a phenol having a carbon number of 6 or more, and preferably a C6-C15 phenol. Specifically, the phenol compound is at least one selected from the group consisting of thymol, ethyl maltol, methyl maltol, 3-propenyl-6-ethoxyphenol, and isoeugenol.

[0070] In the present application, the ester compound is an ester having a carbon number of more than 7, and preferably a C8-C17 ester. Specifically, the ester compound is at least one selected from the group consisting of methyl salicylate, methyl cinnamate, ethyl cinnamate, ethyl phenylacetate, methyl phenylacetate, geranyl phenylacetate, phenethyl phenylacetate, isoamyl phenylacetate, benzyl salicylate, p-methylbenzyl acetate, benzyl acetate, isobutyl benzoate, isoamyl salicylate, benzyl cinnamate, phenethyl cinnamate, linalyl formate, linalyl acetate, linalyl isobutyrate, menthyl acetate, terpinyl acetate, and borneol acetate.

[0071] In the microcapsule of the present application, in a preferred case, the capsule wall comprises an inner layer and an outer layer, the inner layer is resin, and the outer layer is rubber material. In this preferred case, the microcapsule material is particularly suitable for road asphalt, on the one hand, the microcapsule has a certain strength to meet the requirements of road use; on the other hand, the rubber material as the outer layer of the capsule wall can effectively fuse with asphalt, the rubber material has good adhesion, and forms a strong combination with the resin (particularly melamine resin) as the inner layer of the capsule wall, when the asphalt road surface cracks, the material can effectively improve the probability of breaking, the outer layer of the capsule wall is torn to drive the inner layer of the capsule wall to be torn, and a repairing agent is released to achieve the purpose of automatic repair.

[0072] Further preferably, the mass ratio of the inner layer to the outer layer is 2.4-5:1, and specifically, for example, can be 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1, or 5:1.

[0073] In the present application, the content of the capsule core of the microcapsule, the content of the capsule wall, and the mass of the inner layer and the outer layer of the capsule wall are detected by the following method: the microcapsule is added into a volatile solvent (the volatile solvent can be selected from one or more of carbon tetrachloride, dichloromethane, and trichloroethylene), and after being sufficiently dissolved and filtered, the first solid powder obtained is sufficiently dried, and the difference between the mass of the first solid powder and the initial microcapsule is the mass of the outer layer of the capsule wall; the first solid powder obtained is further ground, added into toluene, and after being sufficiently dissolved and filtered, the second solid powder obtained is sufficiently dried, and the difference between the mass of the second solid powder and the first solid powder is the mass of the capsule core; the mass of the inner layer of the capsule wall is the mass of the microcapsule minus the mass of the outer layer of the capsule wall and the mass of the capsule core.

[0074] In the present application, the resin can be at least one of melamine resin, urea-formaldehyde resin, and polymethyl methacrylate, and most preferably is melamine resin.

[0075] In the present application, the rubber material can be at least one of chlorinated rubber, styrene-butadiene rubber, and chloroprene rubber.

[0076] In some specific embodiments of the present application, the microcapsule comprises a capsule core and a capsule wall, the capsule core is wrapped in the capsule wall, the capsule core contains an active component, and the modulus of elasticity of the microcapsule and the thickness of the capsule wall satisfy the following formula:

[0077] Y = 0.42X 2 -0.92X + T

[0078] wherein Y is the modulus of elasticity of the microcapsule, in GPa; X is the thickness of the capsule wall, in pm; and T is 1±0.1;

[0079] The thickness of the capsule wall is 0.5-5 pm, and the content of the core can be 27-53 wt.% and the content of the capsule wall can be 47-73 wt.% based on the total weight of the microcapsule.

[0080] In some embodiments of the present application, the microcapsule comprises a core and a wall, the core is wrapped in the wall, the core contains an active component, and the modulus of elasticity of the microcapsule and the thickness of the capsule wall satisfy the following formula:

[0081] Y = 0.42X 2 -0.92X + T

[0082] wherein Y is the modulus of elasticity of the microcapsule, in GPa; X is the thickness of the capsule wall, in pm; and T is 1±0.1;

[0083] The thickness of the capsule wall is 0.5-5 pm, and the content of the core can be 27-53 wt.% and the content of the capsule wall can be 47-73 wt.% based on the total weight of the microcapsule.

[0084] The active component is a repairing agent for self-repairing of road cracks and / or an inhibitor for inhibiting release of asphalt fume;

[0085] The capsule wall comprises an inner layer and an outer layer, the inner layer is a resin, the outer layer is a rubber material, and the mass ratio of the inner layer to the outer layer is 2.4-5:1.

[0086] In some embodiments of the present application, the microcapsule comprises a core and a wall, the core is wrapped in the wall, the core contains an active component, and the modulus of elasticity of the microcapsule and the thickness of the capsule wall satisfy the following formula:

[0087] Y = 0.42X 2 -0.92X + T

[0088] wherein Y is the modulus of elasticity of the microcapsule, in GPa; X is the thickness of the capsule wall, in pm; and T is 1±0.1;

[0089] The thickness of the capsule wall is 0.5-5 pm, and the content of the core can be 27-53 wt.% and the content of the capsule wall can be 47-73 wt.% based on the total weight of the microcapsule.

[0090] The active component is a repairing agent (e.g. aromatic hydrocarbon-rich component) for repairing road cracks.

[0091] The capsule wall comprises an inner layer and an outer layer, the inner layer is melamine resin, the outer layer is rubber material, and the mass ratio of the inner layer to the outer layer is 2.4-5:1.

[0092] In some embodiments of the present application, the microcapsule comprises a capsule core and a capsule wall, the capsule core is wrapped in the capsule wall, the capsule core contains an active component, and the elastic modulus of the microcapsule and the thickness of the capsule wall satisfy the following formula:

[0093] Y=0.42X 2 -0.92X+T

[0094] Wherein, Y is the elastic modulus of the microcapsule, unit: GPa; X is the thickness of the capsule wall, unit: μm; T is 1±0.1;

[0095] The thickness of the capsule wall is 0.5-1.5 μm;

[0096] The active component is an inhibitor (e.g. aldehyde compound, ketone compound, alcohol compound, phenol compound or ester compound) for inhibiting the release of asphalt smoke;

[0097] The capsule wall comprises an inner layer and an outer layer, the inner layer is melamine resin, the outer layer is rubber material;

[0098] The mass ratio of the capsule core, the inner layer and the outer layer is 1:0.7-1:0.2-0.3.

[0099] In some embodiments of the present application, the microcapsule comprises a capsule core and a capsule wall, the capsule core is wrapped in the capsule wall, the capsule core contains an active component, and the elastic modulus of the microcapsule and the thickness of the capsule wall satisfy the following formula:

[0100] Y=0.42X 2 -0.92X+T

[0101] Wherein, Y is the elastic modulus of the microcapsule, unit: GPa; X is the thickness of the capsule wall, unit: μm; T is 1±0.1;

[0102] The thickness of the capsule wall is 2.1-3 μm;

[0103] The active component is an inhibitor (e.g. aldehyde compound, ketone compound, alcohol compound, phenol compound or ester compound) for inhibiting the release of asphalt smoke;

[0104] The capsule wall comprises an inner layer and an outer layer, the inner layer is melamine resin, the outer layer is rubber material;

[0105] The mass ratio of the capsule core, the inner layer and the outer layer is 1:1.2-1.5:0.4-0.5.

[0106] In some specific embodiments of the present application, the microcapsule comprises a capsule core and a capsule wall, the capsule core is wrapped in the capsule wall, the capsule core contains an active component, and the elastic modulus of the microcapsule and the thickness of the capsule wall satisfy the following formula:

[0107] Y=0.42X 2 -0.92X+T

[0108] Wherein, Y is the elastic modulus of the microcapsule, unit: GPa; X is the thickness of the capsule wall, unit: μm; T is 1±0.1;

[0109] The thickness of the capsule wall is 3.1-5 μm;

[0110] The active component is an inhibitor (such as aldehyde compound, ketone compound, alcohol compound, phenolic compound or ester compound) for inhibiting the release of asphalt smoke;

[0111] The capsule wall comprises an inner layer and an outer layer, the inner layer is melamine resin, and the outer layer is rubber material;

[0112] The mass ratio of the capsule core, the inner layer and the outer layer is 1:1.7-2:0.6-0.7.

[0113] The present application also provides a preparation method of the microcapsule, which comprises:

[0114] (1) mixing an active component, an emulsifier and water to form an oil-in-water emulsion;

[0115] (2) reacting the oil-in-water emulsion with a resin prepolymer, then filtering, washing and drying to obtain a pre-coated material;

[0116] (3) mixing a rubber material with the pre-coated material in the presence of a volatile solvent, then mixing the obtained mixture with water, and heating to volatilize the volatile solvent to obtain the microcapsule.

[0117] In step (1), the mixing process can be carried out in a shearing machine, and the operating conditions can include: rotation speed of 2000-4000 r / min, time of 20-30 min.

[0118] In step (1), the mass ratio of the amount of the active component, the emulsifier and water can be 1:(0.05-0.09):(6-9).

[0119] In some embodiments, the operation process of step (1) is: dissolving the active component in water, then adding the emulsifier, and then performing high-speed shearing emulsification at a rotation speed of 2000-4000 r / min.

[0120] In step (2), the pH value of the oil-in-water emulsion is adjusted to below 5, preferably 2-4, before the oil-in-water emulsion is reacted with the resin prepolymer. The reagent used to adjust the pH value can be a conventional inorganic acid solution, such as dilute hydrochloric acid.

[0121] In step (2), the reaction of the oil-in-water emulsion with the resin prepolymer is performed under stirring, the stirring speed can be 400-800 r / min, the reaction temperature can be 60-90℃, and the time can be 1-5 h.

[0122] In step (2), the filtration process can be suction filtration.

[0123] In step (2), the washing process can include washing with water and ethanol for two or more times, respectively.

[0124] In step (2), the drying process can be performed in an oven, the drying temperature can be 60-90℃, and the time can be 5-10 h.

[0125] In step (2), the resin prepolymer can be one or more of melamine resin prepolymer, urea-formaldehyde resin prepolymer, and polymethyl methacrylate prepolymer. In a preferred case, the resin prepolymer is melamine resin prepolymer. The preparation method of the melamine resin prepolymer can include: mixing and dissolving melamine and formaldehyde solution with water, adjusting the pH value to 7.5-9.5, and then placing in a constant temperature water bath at 60-90℃, and reacting under stirring for 0.5-3.5 h. In the preparation process of the melamine resin prepolymer, the concentration of the formaldehyde solution can be 30-40 wt.%. The mass ratio of the use amounts of the melamine, the formaldehyde solution, and water can be 1:(2-3):(8-10).

[0126] In step (3), the mass ratio of the use amounts of the rubber material, the volatile solvent, and water can be 1:(10-20):(50-150).

[0127] In the method of the present application, the use amounts of the active component, the resin prepolymer, and the rubber material are such that the content of the core in the prepared microcapsules is 27-53 wt.%, and the content of the wall is 47-73 wt.%.

[0128] In the method of the present application, the active component can be selected from one or at least two or more of any combination of aromatic hydrocarbon-rich components, aldehyde compounds, ketone compounds, alcohol compounds, phenol compounds and ester compounds. Specifically, the aromatic hydrocarbon-rich components, the aldehyde compounds, the ketone compounds, the alcohol compounds, the phenol compounds and the ester compounds are selected from the same as described above.

[0129] In the method of the present application, the rubber material can be at least one of chlorinated rubber, styrene-butadiene rubber and neoprene.

[0130] In the method of the present application, the emulsifier can be at least one of sodium naphthenate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, cetyl trimethyl ammonium chloride, cetyl trimethyl ammonium bromide, cetyl dimethyl hydroxyethyl ammonium chloride, nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether and cetyl polyoxyethylene ether.

[0131] In the method of the present application, the volatile solvent can be at least one of carbon tetrachloride, dichloromethane and trichloroethylene.

[0132] The present application also provides microcapsules prepared by the above method.

[0133] The present application also provides the use of the above microcapsules in road asphalt.

[0134] The microcapsules, the method for preparing the same and the use thereof of the present application are further illustrated by the following examples. The examples are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0135] In the following examples, the experimental methods are all conventional methods in the art unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0136] Example 1

[0137] (1) 1 part by weight of catalytic cracking slurry (aromatic hydrocarbon content of 50 wt.%) was added to 9 parts by weight of water at 60°C, followed by the addition of 0.05 parts by weight of cetyl trimethyl ammonium bromide, and an oil-in-water emulsion was formed in the water phase by shearing emulsification with a shearing machine at 2000 r / min for 30 min.

[0138] (2) 1 part by weight of melamine, 2 parts by weight of a formaldehyde solution with a concentration of 37 wt.% and 8 parts by weight of deionized water were fully dissolved in a three-necked flask, the pH value was adjusted to 8.5, and then the mixture was placed in a constant temperature water bath at 60°C and stirred at 800 r / min for 0.5 h to prepare a melamine resin prepolymer.

[0139] To 1 part by weight of the oil-in-water emulsion, add dilute hydrochloric acid dropwise to adjust the pH to 2. Slowly add 0.18 parts by weight of the prepared melamine resin prepolymer to the oil-in-water emulsion, stir at 700 r / min, and react at 75°C for 2 h. After the reaction is completed, the resulting mixed solution is suction filtered, washed twice with water and ethanol, respectively, and dried in an oven at 60°C for 10 h to obtain the pre-coated material.

[0140] (3) Dissolve 0.21 parts by weight of chlorinated rubber in 1 part by weight of dichloromethane, and add 1 part by weight of the pre-coated material, and mix well. Add the resulting mixture to water, and stir at 500 r / min, and raise the temperature to evaporate the solvent to obtain microcapsules A1, which have a size of 7-9 μm, and an SEM image thereof is shown in Figure 1 The content of the core in the microcapsules is 30 wt.%, the content of the wall is 70 wt.%, and the mass ratio of the inner layer to the outer layer in the wall is 3.1:1.

[0141] The elastic modulus of the microcapsules A1 is 2.4 GPa, measured by a nanoindenter, and the thickness of the wall of the microcapsules A1 is 3.2 μm, measured by a scanning electron microscope on a frozen section of the microcapsules, which is consistent with the calculation formula Y = 0.42X 2 -0.92X + T.

[0142] Example 2

[0143] (1) Add 1 part by weight of waste lubricating oil (aromatic hydrocarbon content of 52 wt.%) to 7 parts by weight of water at 60°C, and then add 0.06 parts by weight of nonylphenol polyoxyethylene ether, and shear emulsify at 2500 r / min for 25 min to form an oil-in-water emulsion in the aqueous phase.

[0144] (2) Dissolve 1 part by weight of melamine, 3 parts by weight of a formaldehyde solution with a concentration of 37 wt.% and 10 parts by weight of deionized water in a three-necked flask, adjust the pH to 7.5, and then place in a thermostatic water bath at 80°C, and stir at 600 r / min for 1 h to prepare a melamine resin prepolymer.

[0145] To 1 part by weight of the oil-in-water emulsion, add dilute hydrochloric acid dropwise to adjust the pH to 4. Slowly add 0.13 parts by weight of the prepared melamine resin prepolymer to the oil-in-water emulsion, stir at 600 r / min, and react at 70°C for 3 h. After the reaction is completed, the resulting mixed solution is suction filtered, washed twice with water and ethanol, respectively, and dried in an oven at 70°C for 8 h to obtain the pre-coated material.

[0146] (3) 0.15 parts by weight of chlorobutyl rubber was dissolved in 3 parts by weight of carbon tetrachloride, 1 part by weight of the pre-coated material was added, and the mixture was thoroughly stirred. The obtained mixture was added to water, stirring was carried out at 600 r / min, and the temperature was raised to volatilize the solvent, to obtain microcapsules A2, with a size of 4-6 μm. It was detected that the content of the core in the microcapsules was 43 wt.%, the content of the wall was 57 wt.%, and the mass ratio of the inner layer to the outer layer in the wall was 3.4:1.

[0147] The elastic modulus of the microcapsules A2 was measured by nanoindentation to be 0.7 GPa, and the thickness of the wall of the microcapsules A2 was measured by scanning electron microscopy of a frozen section of the microcapsules to be 1.5 μm, which was consistent with the calculation formula Y = 0.42X 2 -0.92X + T.

[0148] Example 3

[0149] (1) After 1 part by weight of furfural extract oil (aromatic hydrocarbon content of 53 wt.%) was added to 7 parts by weight of water at 60°C, 0.09 parts by weight of octylphenol polyoxyethylene ether was added, and the oil-in-water emulsion was formed in the aqueous phase by shearing emulsification with a shearing machine at 3000 r / min for 20 min.

[0150] (2) 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 9 parts by weight of deionized water were thoroughly dissolved in a three-necked flask, the pH value was adjusted to 8, and then the mixture was placed in a constant temperature water bath at 70°C, and stirred at 500 r / min for 2 h to prepare a melamine resin prepolymer.

[0151] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 3, and 0.12 parts by weight of the prepared melamine resin prepolymer was slowly added dropwise to the oil-in-water emulsion, which was stirred at 500 r / min and reacted at 65°C for 3 h. After the reaction was completed, the obtained mixed solution was suction filtered, washed with water and ethanol for 2 times respectively, and dried in an oven at 90°C for 6 h to obtain the pre-coated material.

[0152] (3) 0.2 parts by weight of butadiene-styrene rubber was dissolved in 3 parts by weight of dichloromethane, 1 part by weight of the pre-coated material was added, and the mixture was thoroughly stirred. The obtained mixture was added to water, stirring was carried out at 700 r / min, and the temperature was raised to volatilize the solvent, to obtain microcapsules A3, with a size of 4-6 μm. It was detected that the content of the core in the microcapsules was 43 wt.%, the content of the wall was 57 wt.%, and the mass ratio of the inner layer to the outer layer in the wall was 2.4:1.

[0153] The elastic modulus of the microcapsule A3 was measured by a nanoindenter to be 0.6 GPa, and the thickness of the capsule wall of the microcapsule A3 was measured by a scanning electron microscope to be 1.4 μm, which is consistent with the calculation formula Y = 0.42X 2 -0.92X + T.

[0154] Example 4

[0155] (1) After 1 part by weight of furfural extracted oil (aromatic hydrocarbon content of 55 wt.%) was added into 6 parts by weight of water at 60°C, 0.06 parts by weight of sodium dodecyl benzene sulfonate was added, and the oil-in-water emulsion was formed in the water phase by shearing emulsification with a shearing machine at 4000 r / min for 20 min.

[0156] (2) 1 part by weight of melamine, 3 parts by weight of formaldehyde solution with a concentration of 37 wt.% and 9 parts by weight of deionized water were dissolved in a three-necked flask, the pH value was adjusted to 7.5, and then the melamine resin prepolymer was prepared by stirring at 700 r / min for 2 h in a constant temperature water bath at 60°C.

[0157] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 3, and 0.11 parts by weight of the prepared melamine resin prepolymer was slowly added dropwise into the oil-in-water emulsion, which was stirred at 500 r / min and reacted at 60°C for 5 h. After the reaction, the obtained mixed solution was suction filtered, washed with water and ethanol for 2 times respectively, and dried in an oven at 90°C for 6 h to obtain the pre-coated material.

[0158] (3) 0.16 parts by weight of chlorinated rubber was dissolved in 1.7 parts by weight of dichloromethane, and 1 part by weight of the pre-coated material was added and mixed by stirring. The obtained mixture was added into water, which was stirred at 800 r / min, and the temperature was increased to volatilize the solvent, so that the chlorinated rubber gradually formed a film and adhered to the outer wall of the inner wall coated repair material to obtain the microcapsule A4 with a size of 3-5 μm. It was detected that the content of the capsule core in the microcapsule was 49 wt.%, the content of the capsule wall was 51 wt.%, and the mass ratio of the inner layer to the outer layer in the capsule wall was 2.7:1.

[0159] The elastic modulus of the microcapsule A4 was measured by a nanoindenter to be 0.5 GPa, and the thickness of the capsule wall of the microcapsule A4 was measured by a scanning electron microscope to be 0.7 μm, which is consistent with the calculation formula Y = 0.42X 2 -0.92X + T.

[0160] Example 5

[0161] (1) 1 part by weight of a four-line draw oil (aromatic content of 56 wt.%) was added to 6 parts by weight of 60°C water, then 0.08 parts by weight of cetyltrimethylammonium chloride was added, and the mixture was sheared and emulsified by a shearing machine at 3000 r / min for 30 min to form an oil-in-water emulsion in the water phase.

[0162] (2) 1 part by weight of melamine, 2 parts by weight of a formaldehyde solution with a concentration of 37 wt.% and 9 parts by weight of deionized water were dissolved in a three-necked flask, the pH value was adjusted to 8, and then the mixture was placed in a thermostatic water bath at 90°C and stirred at 400 r / min for 3.5 h to prepare a melamine resin prepolymer.

[0163] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 2, and 0.12 parts by weight of the prepared melamine resin prepolymer was slowly added dropwise to the oil-in-water emulsion, which was stirred at 800 r / min and reacted at 90°C for 1 h. After the reaction was completed, the obtained mixed solution was suction filtered, washed with water and ethanol for 2 times respectively, and dried in an oven at 60°C for 9 h to obtain a pre-coated material.

[0164] (3) 0.18 parts by weight of chlorinated rubber was dissolved in 5 parts by weight of dichloromethane, and 1 part by weight of the pre-coated material was added and mixed by stirring. The obtained mixture was added to water and stirred at 700 r / min, and the temperature was increased to volatilize the solvent, so that the chlorinated rubber gradually formed a film and adhered to the outer wall of the inner wall coating repair material to obtain microcapsules A5 with a size of 3-6 μm. It was detected that the content of the core in the microcapsules was 46 wt.%, the content of the wall was 54 wt.%, and the mass ratio of the inner layer to the outer layer in the wall was 2.5:1.

[0165] The nanoindentation instrument was used to measure that the elastic modulus of the microcapsules A5 was 0.6 GPa, and the scanning electron microscope was used to measure that the thickness of the wall of the microcapsules A5 was 1.0 μm, which was consistent with the calculation formula Y = 0.42X 2 -0.92X + T.

[0166] Example 6

[0167] The microcapsules were prepared according to the method of Example 1 except that the melamine resin prepolymer was replaced by urea-formaldehyde resin prepolymer, wherein the urea-formaldehyde resin prepolymer was prepared by dissolving 1 part by weight of urea, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.%, and 8 parts by weight of deionized water in a three-necked flask, adjusting the pH value to 9, and then placing in a constant temperature water bath at 60°C, and stirring at 800 r / min for 0.5 h to prepare the urea-formaldehyde resin prepolymer. Thus, microcapsules A6 were prepared, which had a size of 6-9 μm. It was detected that the content of the core in the microcapsules was 30 wt.%, the content of the wall was 70 wt.%, and the mass ratio of the inner layer to the outer layer in the wall was 3.1:1.

[0168] The elastic modulus of the microcapsules A6 was measured by a nanoindenter to be 2.1 GPa, and the thickness of the wall of the microcapsules A6 was measured by a scanning electron microscope to be 3.1 μm, which was consistent with the calculation formula Y=0.42X 2 -0.92X+T.

[0169] Comparative Example 1

[0170] (1) After 1 part by weight of catalytic cracking slurry (aromatic hydrocarbon content of 50 wt.%) was added to 9 parts by weight of water at 60°C, 0.05 parts by weight of cetyl trimethyl ammonium bromide was added, and an oil-in-water emulsion was formed in the aqueous phase by shearing emulsification at 2000 r / min for 30 min.

[0171] (2) Melamine, formaldehyde solution with a concentration of 37 wt.% and deionized water were fully dissolved in a three-necked flask, the pH value was adjusted to 8.5, and then placed in a constant temperature water bath at 60°C, and stirred at 800 r / min for 0.5 h to prepare the melamine resin prepolymer.

[0172] Dilute hydrochloric acid was added dropwise to 1 part by weight of the oil-in-water emulsion, the pH value was adjusted to 2, 0.18 parts by weight of the prepared melamine resin prepolymer was slowly added to the oil-in-water emulsion, and stirred at 700 r / min, and reacted at 75°C for 2 h. After the reaction was completed, the obtained mixed solution was suction filtered, washed with water and ethanol for 2 times respectively, and placed in an oven for drying at 60°C for 10 h. The prepared product was used as microcapsules D1, which had a size of 5-7 μm.

[0173] The elastic modulus of the microcapsules D1 was measured by a nanoindenter to be 2.7 GPa, and the thickness of the wall of the microcapsules D1 was measured by a scanning electron microscope to be 2.2 μm, which was not consistent with the calculation formula Y=0.42X 2 -0.92X+T.

[0174] Comparative Example 2

[0175] (1) After 1 part by weight of catalytic cracking slurry oil (aromatic hydrocarbon content of 50 wt.%) was added to 9 parts by weight of 60°C water, 0.05 parts by weight of cetyltrimethylammonium bromide was added, and the oil-in-water emulsion was formed in the aqueous phase by shearing emulsification using a shearing machine at 2000 r / min for 30 min.

[0176] (2) 1 part by weight of melamine, 2 parts by weight of a formaldehyde solution having a concentration of 37 wt.%, and 8 parts by weight of deionized water were thoroughly dissolved in a three-necked flask, the pH value was adjusted to 8.5, and then the mixture was placed in a constant-temperature water bath at 60°C and stirred at 800 r / min for 0.5 h to prepare a melamine resin prepolymer.

[0177] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 2, and 0.18 parts by weight of the prepared melamine resin prepolymer was slowly added dropwise to the oil-in-water emulsion, which was stirred at 700 r / min and reacted at 75°C for 2 h. After the reaction was completed, the obtained mixed solution was suction-filtered, washed with water and ethanol twice, respectively, and dried in an oven at 60°C for 10 h to obtain a pre-coated material.

[0178] (3) 0.1 parts by weight of chlorinated rubber and 1 part by weight of the pre-coated material were directly added to water, which was stirred at 500 r / min, and after drying, microcapsules D2 having a size of 8-10 μm were obtained, wherein in the microcapsules, the chlorinated rubber cannot be wrapped in the form of a film in the outermost layer of the microcapsules.

[0179] The elastic modulus of the microcapsules D2 was measured using a nanoindenter to be 2.6 GPa, and the thickness of the capsule wall of the microcapsules D2 was measured by freezing and slicing the microcapsules using a scanning electron microscope to be 4.1 μm, which does not conform to the calculation formula Y = 0.42X - 0.92X + T. 2

[0180] Test Example 1

[0181] The microcapsules prepared in Examples 1-6 and Comparative Examples 1-2 above were tested.

[0182] Using Donghai No. 70 asphalt, 0.4 wt.% of the microcapsules were added, and referring to the ductility test method in JTG E20-2011 “Standard Test Methods of Bitumen and Bituminous Mixture for Highway Engineering”, the test piece was cut in the middle, and then placed for 24 h, and the change in the front and back ductility was tested, and the healing rate was calculated, and the results are shown in Table 1.

[0183] Healing rate = ductility after cutting for 24 h / ductility before cutting

[0184] Table 1: Test results of asphalt sample ductility

[0185] ​

[0186] As can be seen from the results of Table 1, by using the microcapsule described in the present application and selecting the repairing agent for repairing the cracks of the road surface as the active component, the self-repairing efficiency of the road surface asphalt material can be effectively improved.

[0187] Example 7

[0188] (1) 1 part by weight of p-methoxybenzaldehyde was added to 9 parts by weight of 60°C water, then 0.05 parts by weight of cetyltrimethylammonium bromide was added, and an oil-in-water emulsion was formed in the water phase by shearing emulsification with a shearing machine at 2000 r / min for 30 min.

[0189] (2) 1 part by weight of melamine, 2 parts by weight of a formaldehyde solution with a concentration of 37 wt.%, and 8 parts by weight of deionized water were fully dissolved in a three-necked flask, the pH value was adjusted to 8.5, and then the mixture was placed in a constant-temperature water bath at 60°C and stirred at 800 r / min for 0.5 h to prepare a melamine resin prepolymer.

[0190] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 2, and 0.18 parts by weight of the prepared melamine resin prepolymer was slowly added dropwise to the oil-in-water emulsion, which was stirred at 700 r / min and reacted at 75°C for 2 h. After the reaction was completed, the obtained mixed solution was suction-filtered, washed with water and ethanol for 2 times respectively, and then dried in an oven at 60°C for 10 h to obtain a pre-coated material.

[0191] (3) 0.21 parts by weight of chlorinated rubber was dissolved in 1 part by weight of dichloromethane, and 1 part by weight of the pre-coated material was added and fully stirred and mixed. The obtained mixture was added to water and stirred at 500 r / min, and the temperature was increased to volatilize the solvent to prepare a microcapsule A7 with a size of 7-9 μm. It was detected that the content of the core in the microcapsule was 30 wt.%, the content of the wall was 70 wt.%, and the mass ratio of the inner layer to the outer layer in the wall was 3.1:1.

[0192] The elastic modulus of the microcapsule A7 was measured by a nanoindenter to be 2.1 GPa, and the thickness of the wall of the microcapsule A7 was measured by scanning electron microscopy of a frozen section of the microcapsule to be 3.0 μm, which was consistent with the calculation formula Y = 0.42X - 0.92X + T. 2

[0193] Example 8

[0194] (1) 1 part by weight of acetophenone was added to 7 parts by weight of 60°C water, then 0.06 parts by weight of nonylphenol polyoxyethylene ether was added, and an oil-in-water emulsion was formed in the water phase by shearing emulsification with a shearing machine at 2500 r / min for 25 min.

[0195] ​(2) 1 part by weight of melamine, 3 parts by weight of formaldehyde solution with a concentration of 37 wt.%, and 10 parts by weight of deionized water were dissolved in a three-necked flask, the pH value was adjusted to 7.5, and then the mixture was placed in a constant temperature water bath at 80°C and stirred at 600 r / min for 1 h to prepare a melamine resin prepolymer.

[0196] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 4. Then, 0.13 parts by weight of the prepared melamine resin prepolymer was slowly added dropwise to the oil-in-water emulsion, which was stirred at 600 r / min and reacted at 70°C for 3 h. After the reaction, the obtained mixed solution was suction filtered, washed with water and ethanol for 2 times respectively, and then dried in an oven at 70°C for 8 h to obtain a pre-coated material.

[0197] (3) 0.15 parts by weight of chlorobutyl rubber was dissolved in 3 parts by weight of carbon tetrachloride, and 1 part by weight of the pre-coated material was added and mixed by stirring. The obtained mixture was added to water and stirred at 600 r / min, and the temperature was raised to evaporate the solvent to obtain microcapsules A8 with a size of 4-6 μm. It was detected that the content of the core in the microcapsules was 43 wt.%, the content of the wall was 57 wt.%, and the mass ratio of the inner layer to the outer layer in the wall was 3.4:1.

[0198] The elastic modulus of the microcapsules A8 was measured by a nanoindenter to be 0.6 GPa, and the thickness of the wall of the microcapsules A8 was measured by scanning electron microscopy of a frozen section of the microcapsules to be 1.4 μm, which was consistent with the calculation formula Y = 0.42X - 0.92X + T. 2

[0199] Example 9

[0200] (1) 1 part by weight of benzyl alcohol was added to 7 parts by weight of water at 60°C, and then 0.09 parts by weight of octylphenol polyoxyethylene ether was added. The mixture was sheared and emulsified by a shearing machine at 3000 r / min for 20 min to form an oil-in-water emulsion in the water phase.

[0201] (2) 1 part by weight of melamine, 2 parts by weight of formaldehyde solution with a concentration of 37 wt.%, and 9 parts by weight of deionized water were dissolved in a three-necked flask, the pH value was adjusted to 8, and then the mixture was placed in a constant temperature water bath at 70°C and stirred at 500 r / min for 2 h to prepare a melamine resin prepolymer.

[0202] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 4. Then, 0.12 parts by weight of the prepared melamine resin prepolymer was slowly added dropwise to the oil-in-water emulsion, which was stirred at 500 r / min and reacted at 65°C for 3 h. After the reaction, the obtained mixed solution was suction filtered, washed with water and ethanol for 2 times respectively, and then dried in an oven at 90°C for 6 h to obtain a pre-coated material.​

[0203] (3) 0.2 parts by weight of styrene-butadiene rubber was dissolved in 3 parts by weight of dichloromethane, 1 part by weight of the pre-coating material was added, and the mixture was stirred thoroughly. The obtained mixture was added to water, stirring was carried out at 700 r / min, and the temperature was raised to volatilize the solvent, to obtain microcapsules A9, with a size of 4-6 μm. It was detected that the content of the core in the microcapsules was 43 wt.%, the content of the wall was 57 wt.%, and the mass ratio of the inner layer to the outer layer in the wall was 2.4:1.

[0204] The elastic modulus of the microcapsules A9 was measured by nanoindentation to be 0.5 GPa, and the thickness of the wall of the microcapsules A9 was measured by scanning electron microscopy of a frozen section of the microcapsules to be 1.2 μm, which was consistent with the calculation formula Y = 0.42X 2 -0.92X + T.

[0205] Example 10

[0206] (1) After 1 part by weight of 3-propenyl-6-ethoxyphenol was added to 6 parts by weight of water at 60°C, 0.06 parts by weight of sodium dodecylbenzenesulfonate was added, and the oil-in-water emulsion was formed in the aqueous phase by shearing emulsification with a shear machine at 4000 r / min for 20 min.

[0207] (2) 1 part by weight of melamine, 3 parts by weight of a formaldehyde solution with a concentration of 37 wt.%, and 9 parts by weight of deionized water were dissolved thoroughly in a three-necked flask, the pH value was adjusted to 7.5, and then the mixture was placed in a constant-temperature water bath at 60°C and stirred at 700 r / min for 2 h of reaction to prepare a melamine resin prepolymer.

[0208] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 3, and 0.11 parts by weight of the prepared melamine resin prepolymer was added dropwise to the oil-in-water emulsion, which was stirred at 500 r / min and reacted at 60°C for 5 h. After the reaction, the obtained mixed solution was suction-filtered, washed with water and ethanol for 2 times respectively, and dried in an oven at 90°C for 6 h to obtain the pre-coating material.

[0209] (3) 0.16 parts by weight of chlorinated rubber was dissolved in 1.7 parts by weight of dichloromethane, 1 part by weight of the pre-coating material was added, and the mixture was stirred thoroughly. The obtained mixture was added to water, stirring was carried out at 800 r / min, and the temperature was raised to volatilize the solvent, so that the chlorinated rubber gradually formed a film and adhered to the outer wall of the inner wall coating repair material, to obtain microcapsules A10, with a size of 3-5 μm. It was detected that the content of the core in the microcapsules was 49 wt.%, the content of the wall was 51 wt.%, and the mass ratio of the inner layer to the outer layer in the wall was 2.7:1.

[0210] The elastic modulus of the microcapsule A10 was measured by a nanoindenter to be 0.4 GPa, and the thickness of the capsule wall of the microcapsule A10 was measured by a scanning electron microscope to be 0.8 μm, which is consistent with the calculation formula Y = 0.42X 2 -0.92X + T.

[0211] Example 11

[0212] (1) After 1 part by weight of phenyl ethyl phenylacetate was added to 6 parts by weight of 60°C water, 0.08 parts by weight of cetyl trimethyl ammonium chloride was added, and the oil-in-water emulsion was formed in the water phase by shearing emulsification with a shearing machine at 3000 r / min for 30 min.

[0213] (2) 1 part by weight of melamine, 2 parts by weight of a formaldehyde solution with a concentration of 37 wt.%, and 9 parts by weight of deionized water were dissolved in a three-necked flask, the pH value was adjusted to 8, and then the mixture was placed in a constant temperature water bath at 90°C, and stirred at 400 r / min for 3.5 h to prepare a melamine resin prepolymer.

[0214] To 1 part by weight of the oil-in-water emulsion, dilute hydrochloric acid was added dropwise to adjust the pH value to 2, and 0.12 parts by weight of the prepared melamine resin prepolymer was slowly added dropwise to the oil-in-water emulsion, which was stirred at 800 r / min, and reacted at 90°C for 1 h. After the reaction was completed, the obtained mixed solution was suction filtered, washed with water and ethanol for 2 times respectively, and dried in an oven at 60°C for 9 h to obtain a pre-coated material.

[0215] (3) 0.18 parts by weight of chlorinated rubber was dissolved in 5 parts by weight of dichloromethane, and 1 part by weight of the pre-coated material was added and mixed by stirring. The obtained mixture was added to water, and stirred at 700 r / min, and the temperature was increased to volatilize the solvent, so that the chlorinated rubber gradually formed a film and adhered to the outer wall of the inner wall coated repair material to obtain microcapsules A11 with a size of 3-6 μm. It was detected that the content of the capsule core in the microcapsules was 46 wt.%, the content of the capsule wall was 54 wt.%, and the mass ratio of the inner layer to the outer layer in the capsule wall was 2.5:1.

[0216] The elastic modulus of the microcapsule A11 was measured by a nanoindenter to be 0.5 GPa, and the thickness of the capsule wall of the microcapsule A11 was measured by a scanning electron microscope to be 0.9 μm, which is consistent with the calculation formula Y = 0.42X 2 -0.92X + T.

[0217] Comparative Example 3

[0218] The microcapsules were prepared according to the method of Example 7, except that in step (1), the amount of water was increased to 15 parts by weight and the amount of chlorinated rubber was increased to 0.25 parts by weight, and finally the capsule D3 was prepared, which had a size of 6-8 μm.

[0219] The elastic modulus of the microcapsule D3 was measured by nanoindenter to be 3.3 GPa, and the thickness of the capsule wall of the microcapsule D3 was measured by scanning electron microscope to be 3.5 μm, which did not conform to the calculation formula Y = 0.42X 2 -0.92X + T.

[0220] Comparative Example 4

[0221] The microcapsules were prepared according to the method of Example 7, except that in step (3), the amount of chlorinated rubber was decreased to 0.11 parts by weight and the amount of melamine resin prepolymer was increased to 0.23 parts by weight, and finally the capsule D4 was prepared, which had a size of 5-7 μm.

[0222] The elastic modulus of the microcapsule A6 was measured by nanoindenter to be 2.6 GPa, and the thickness of the capsule wall of the microcapsule A6 was measured by scanning electron microscope to be 2.9 μm, which did not conform to the calculation formula Y = 0.42X 2 -0.92X + T.

[0223] Test Example 2

[0224] The microcapsules prepared in Examples 7-11 and Comparative Examples 3-4 above were tested.

[0225] Donghai No. 70 asphalt was used, and 0.4 wt.% of the microcapsules were added, and the asphalt fumes were enriched under the condition of heating at 163 °C for 6 h, and the asphalt fumes were tested and analyzed by gas chromatography and total hydrocarbon analyzer, and the results are shown in Table 2.

[0226] Table 2: Test results of asphalt fumes

[0227]

[0228]

[0229] As can be seen from the results in Table 2, by using the microcapsules according to the present application and selecting the inhibitor for inhibiting the release of asphalt fumes as the active component, the emission of asphalt fumes can be effectively reduced, and the pollution to the environment can be reduced.

[0230] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A microcapsule, characterized in that, The microcapsule comprises a capsule core and a capsule wall, the capsule core is wrapped in the capsule wall, the capsule core contains an active component, and the elastic modulus of the microcapsule and the thickness of the capsule wall satisfy the following formula: Y = 0.42X 2 - 0.92X + T Wherein, Y is the elastic modulus of the microcapsule, the unit is GPa; X is the thickness of the capsule wall, the unit is μm; T is 1±0.1; The elastic modulus of the microcapsule is obtained by mechanical property testing of the microcapsule by a nanoindenter, and the thickness of the capsule wall is obtained by testing the frozen section of the microcapsule by a scanning electron microscope; The active component is a repairing agent for self-repairing of road cracks and / or an inhibitor for inhibiting the release of asphalt smoke; the repairing agent for self-repairing of road cracks is a rich aromatic component; The rich aromatic component is selected from at least one of catalytic cracking slurry oil, four-line reduced extraction oil, furfural extraction oil and waste lubricating oil; The inhibitor for inhibiting the release of asphalt smoke is at least one of an aldehyde compound, a ketone compound, an alcohol compound, a phenolic compound and an ester compound; The aldehyde compound is selected from at least one of a fatty aldehyde with a carbon atom number greater than or equal to 7 and an aromatic aldehyde with a carbon atom number greater than or equal to 6; The ketone compound is selected from at least one of a fatty ketone with a carbon atom number greater than or equal to 8 and an aromatic ketone with a carbon atom number greater than or equal to 8; The alcohol compound is an alcohol with a carbon atom greater than 6; The phenolic compound is a phenol with a carbon atom greater than or equal to 6; The ester compound is an ester with a carbon atom number greater than 7.

2. The microcapsule according to claim 1, wherein The content of the capsule core is 27-53wt.% based on the total weight of the microcapsule, and the content of the capsule wall is 47-73wt.%.

3. The microcapsule of claim 1, wherein The aromatic content of the rich aromatic component is 45-65wt.%.

4. The microcapsule of claim 1, wherein The aldehyde compound is at least one of p-methylbenzaldehyde, decanal, o-carboxybenzaldehyde, p-isopropylbenzaldehyde, cinnamyl aldehyde, p-hydroxybenzaldehyde, p-methoxybenzaldehyde, 2-methyl-3-(3,4-methylene-dioxyphenyl) propionaldehyde, 3,4-methylenedioxybenzaldehyde, 3-(4-isopropylphenyl)-2-methylpropionaldehyde, ethyl vanillin, phenylacetaldehyde, anisic aldehyde, nonadiene-2,6-aldehyde, 2,6-dimethyl-2,6-octadienal, vanillin, citronellal, nerol, hydroxymethyl pentyl cyclohexene acetal, p-diethylaminobenzaldehyde and undecenal; The ketone compound is at least one of 6-methyl-3,5-heptadiene-2-ketone, 2-undecanone, acetophenone, ionone, irisone, methyl ionone, damascone and dihydrodamascone; The alcohol compound is at least one of cinnamic alcohol, menthol, cis-3,7-dimethyl-2,6-octadienol, citronellol, geraniol, myrcenol, 2,6,10-trimethyl-2,6,10-dodecatrien-12-ol, lavandulol, benzyl alcohol, 2-phenylethanol, dihydromycenol, tetrahydrolinalool and nerolidol; The phenolic compound is at least one of thymol, ethyl maltol, methyl maltol, 3-propenyl-6-ethoxyphenol and isoeugenol; The ester compound is at least one of methyl salicylate, methyl cinnamate, ethyl cinnamate, ethyl phenylacetate, methyl phenylacetate, geranyl phenylacetate, phenethyl phenylacetate, isoamyl phenylacetate, benzyl salicylate, p-methylbenzyl acetate, benzyl acetate, isobutyl benzoate, isoamyl salicylate, benzyl laurate, phenethyl laurate, linalyl formate, linalyl acetate, linalyl isobutyrate, menthyl acetate, terpinyl acetate, and bornyl acetate.

5. The microcapsule according to claim 1, wherein The thickness of the capsule wall is 0.5-5 μm.

6. The microcapsule of claim 1, wherein The capsule wall comprises an inner layer and an outer layer, the inner layer is a resin, and the outer layer is a rubber material.

7. The microcapsule of claim 6, wherein The mass ratio of the inner layer to the outer layer is 2.4-5:

1.

8. The microcapsule of claim 6, wherein The resin is at least one of melamine resin, urea-formaldehyde resin, and polymethyl methacrylate.

9. The microcapsule of claim 6, wherein The rubber material is at least one of chlorinated rubber, styrene-butadiene rubber, and neoprene.

10. The microcapsule of claim 1, wherein The size of the microcapsule is 50 μm or less.

11. The microcapsule of claim 1, wherein The size of the microcapsule is 20 μm or less.

12. The microcapsule of claim 1, wherein The size of the microcapsule is 3-15 μm.

13. A process for the preparation of microcapsules according to any one of claims 1 to 12, characterized in that The method comprises: (1) mixing an active component, an emulsifier, and water to form an oil-in-water emulsion; (2) reacting the oil-in-water emulsion with a resin prepolymer, and then filtering, washing, and drying to obtain a pre-coated material; (3) mixing a rubber material with the pre-coated material in the presence of a volatile solvent, and then mixing the obtained mixture with water, and heating to volatilize the volatile solvent to obtain a microcapsule.

14. The method of claim 13, wherein, In step (1), the mass ratio of the active component, the emulsifier, and water is 1:(0.05-0.09):(6-9).

15. The method of claim 13, wherein, In step (2), the pH value of the oil-in-water emulsion is adjusted to 5 or less before the oil-in-water emulsion is reacted with the resin prepolymer.

16. The method of claim 13, wherein, In step (2), the resin prepolymer is a melamine resin prepolymer, and the preparation method of the melamine resin prepolymer comprises: mixing and dissolving melamine and a formaldehyde solution with water, adjusting the pH value to 7.5-9.5, and then placing in a constant-temperature water bath at 60-90°C for 0.5-3.5 h under stirring; the concentration of the formaldehyde solution is 30-40 wt.%; the mass ratio of the melamine, the formaldehyde solution, and water is 1:(2-3):(8-10).

17. The method of claim 13, wherein, In step (3), the mass ratio of the rubber material, the volatile solvent, and water is 1:(10-20):(50-150).

18. The method of claim 13, wherein, The active component is one or an arbitrary combination of at least two or more of aromatic-rich components, aldehyde compounds, ketone compounds, alcohol compounds, phenolic compounds, and ester compounds.

19. The method of claim 13, wherein, The rubber material is at least one of chlorinated rubber, styrene-butadiene rubber, and neoprene.

20. The method of claim 13, wherein, The emulsifier is at least one selected from sodium abietate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, cetyl dimethyl hydroxyethyl ammonium chloride, nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, and hexadecyl polyoxyethylene ether.

21. The method of claim 13, wherein, The volatile solvent is at least one selected from carbon tetrachloride, dichloromethane, and trichloroethylene.

22. Use of the microcapsules according to any one of claims 1 to 12 in road asphalt.

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