Microcapsule self-repairing material for concrete structure cracks and preparation method of microcapsule self-repairing material

Abstract

The invention relates to the technical field of self-repairing materials, and provides a microcapsule self-repairing material for concrete structure cracks and a preparation method of the microcapsule self-repairing material. The microcapsule self-repairing material for concrete structure cracks comprises a first microcapsule, the first microcapsule comprises a core material and a shell material in a mass ratio of (1.1-2.5): 1; the shell material is prepared from the following raw materials in parts by weight: 100 parts of urea formaldehyde compound; the core material comprises the following raw material components in parts by weight: 100 parts of epoxy resin and 8-12 parts of a latent curing agent; the latent curing agent comprises a component A and a dicyandiamide compound in a mass ratio of (1: 9)-(9: 1); the component A comprises one or two of a modified amine compound and an imidazole compound. According to the technical scheme, the problem that a microcapsule self-repairing material in the related technology is insufficient in self-repairing effect on concrete cracks is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of self-repairing materials, and in particular to a microcapsule self-repairing material for concrete structure cracks and a preparation method thereof. Background Art

[0002] During the use of concrete, cracks are easily generated due to various external loads and environmental factors, which lead to the entry of corrosive media into the structure, causing corrosion of concrete or steel bars. Traditional post-maintenance methods often fail to seal cracks in a timely and effective manner, and are costly.

[0003] The core of microcapsule self-healing technology is to encapsulate the repair agent (such as polyurethane) in a shell material and pre-disperse it in the concrete mixture. When cracks appear in the concrete and extend to the location of the microcapsules, the microcapsules rupture under the action of stress, and the repair agent is released into the cracks and undergoes a curing reaction to form a sealing layer, thereby timely and effectively sealing the cracks and preventing moisture and other substances from entering the concrete structure and causing erosion and damage to the internal structure. However, existing microcapsule self-healing materials still have limited self-repair effects on concrete cracks, affecting the durability of the concrete. Summary of the invention

[0004] The present invention provides a microcapsule self-repairing material for concrete structure cracks and a preparation method thereof, which solves the problem that the microcapsule self-repairing material in the related art has insufficient self-repairing effect on concrete cracks.

[0005] The technical solution of the present invention is as follows: The present invention provides a microcapsule self-repairing material for concrete structure cracks, comprising a first microcapsule; The first microcapsule comprises a core material and a shell material in a mass ratio of 1.1 to 2.5:1; The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde compound; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 8-12 parts of latent curing agent; The latent curing agent comprises component A and a dicyandiamide compound in a mass ratio of 1:9 to 9:1; The component A includes one or two of modified amine compounds and imidazole compounds.

[0006] As a further technical solution, the urea-formaldehyde compound includes one of a urea-formaldehyde prepolymer and a polyurea-formaldehyde monomer; The modified amine compound includes one or more of aromatic modified amines, aliphatic modified amines, and alicyclic modified amines; The imidazole compound includes one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole and imidazole complex.

[0007] As a further technical solution, the dicyanamide-based compound includes one or more of dicyandiamide, modified dicyandiamide, dicyandiamide complex, and substituted dicyandiamide derivatives.

[0008] As a further technical solution, the latent curing agent comprises component A and a dicyandiamide compound in a mass ratio of 1:4 to 4:1.

[0009] In the present invention, when the latent curing agent is compounded with component A and a dicyandiamide-based compound in a mass ratio of 1:4 to 4:1, the self-repairing effect of the microcapsule self-repairing material on concrete cracks is improved.

[0010] As a further technical solution, the raw materials of the shell material also include the following components: pH regulator and silane coupling agent.

[0011] As a further technical solution, the raw material of the core material further includes at least one of the following components: a filler, a toughening agent, a defoaming agent, and a dispersant.

[0012] The filler may be, for example, nano-silicon dioxide, talc, etc., preferably nano-silicon dioxide.

[0013] The toughening agent may be, for example, an organic toughening agent or an inorganic toughening agent. The organic toughening agent includes ethylene propylene rubber, polybutadiene rubber, etc.; the inorganic toughening agent includes nano-calcium carbonate, nano-titanium dioxide, etc.

[0014] The defoamer may be, for example, a polyether defoamer, a silicone defoamer, etc.; the models of the polyether defoamer include SGR1800, SGRM1811, SPO-30, DZ-1100, etc.; The models of silicone defoamers include Defom 6500, Defom 5300, Defom 5500, etc.

[0015] The dispersant may be, for example, a polycarboxylic acid dispersant, a phosphate dispersant, etc.; the model of the polycarboxylic acid dispersant may be SN-5040, SN-5029, SN-5027, BP-5040, etc.

[0016] As a further technical solution, the epoxy resin includes one of bisphenol A epoxy resin and bisphenol F epoxy resin; The epoxy equivalent of the epoxy resin is 180-220 g / eq.

[0017] As a further technical solution, a second microcapsule is also included; the second microcapsule includes a core material and a shell material in a mass ratio of 1.1 to 2.5:1; The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde compound; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin and 3-6 parts of humate.

[0018] In the present invention, the microcapsule self-repairing material adopts a core material containing a latent curing agent and a second microcapsule to be mixed for use, and the two capsules are ruptured synergistically to achieve effective curing, and have excellent repair performance for concrete cracks.

[0019] The present invention also proposes a method for preparing a microcapsule self-repairing material for concrete structure cracks, comprising the following steps: S1, mixing the shell material raw materials of the first microcapsules, adjusting the pH to 8-9, and obtaining a first shell material mixture; S2, mixing the core material raw materials of the first microcapsules to obtain a first core material mixture; S3, adding the first core material mixture to the first shell material mixture for emulsification, cross-linking, and post-treatment to obtain a first microcapsule; S4, mixing the shell material raw materials of the second microcapsules, adjusting the pH to 8-9, and obtaining a second shell material mixture; S5, mixing the core material raw materials of the second microcapsules to obtain a second core material mixture; S6, adding the second core material mixture to the second shell material mixture for emulsification, cross-linking, and post-treatment to obtain second microcapsules; S7, mixing the first microcapsule and the second microcapsule to obtain a microcapsule self-healing material.

[0020] The present invention also proposes the use of the microcapsule self-repairing material for concrete structure cracks or the microcapsule self-repairing material prepared by the preparation method in concrete, wherein the mass of the microcapsule self-repairing material is 2% to 5% of the mass of the concrete.

[0021] The working principle and beneficial effects of the present invention are: In the present invention, the concrete repair agent is placed in a "dormant" state inside the concrete material through latent curing under a normal temperature and high alkalinity environment, thereby avoiding premature curing or loss of activity. When cracks appear and destroy the microcapsule structure, the repair agent and the latent curing agent will rapidly cure under conditions of high pH and humidity triggering to form a solid plugging layer, which has an excellent self-repairing effect on concrete cracks. In addition, the self-repairing microcapsule material of the present invention has a low threshold in terms of material availability and equipment compatibility, and has good prospects for industrial application. It can significantly improve the durability of concrete and reduce the investment in later maintenance. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the following examples and comparative examples, the epoxy resin is a bisphenol A epoxy resin with an epoxy equivalent of 180-220 g / eq; and the urea-formaldehyde prepolymer is purchased from Wuhan Xinzhongxin Chemical Technology Co., Ltd.

[0024] Example 1 A microcapsule self-repairing material for concrete structure cracks, comprising a first microcapsule; The first microcapsule includes a core material and a shell material in a mass ratio of 2.5:1; The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde prepolymer; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 12 parts of latent curing agent; The latent curing agent includes 2-ethyl-4-methylimidazole and dicyandiamide in a mass ratio of 9:1; The preparation method of the microcapsule self-repairing material for concrete structure cracks comprises the following steps: S1, mixing the shell material raw materials of the first microcapsule, adjusting the pH to 8, stirring at 300 rpm for 15 min, to obtain a first shell material mixture; S2, stirring and mixing the core material raw materials of the first microcapsule at 40° C. for 30 minutes to obtain a first core material mixture; S3. Add the first core material mixture to the first shell material mixture, emulsify at 55° C., 600 rpm for 25 min, crosslink at 70° C., 400 rpm for 25 min, centrifuge, wash with water, and dry to obtain a microcapsule self-healing material.

[0025] Example 2 A microcapsule self-repairing material for concrete structure cracks, comprising a first microcapsule; The first microcapsule includes a core material and a shell material in a mass ratio of 2:1; The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde prepolymer; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 8 parts of latent curing agent, 5 parts of nano silicon dioxide (particle size 50nm), and 0.4 parts of organosilicon defoaming agent Defom 6500; The latent curing agent includes 2-ethyl-4-methylimidazole and dicyandiamide in a mass ratio of 8:1; The preparation method of the microcapsule self-repairing material for concrete structure cracks comprises the following steps: S1, mixing the shell material raw materials of the first microcapsule, adjusting the pH to 9, stirring at 300 rpm for 15 min, to obtain a first shell material mixture; S2, stirring and mixing the core material raw materials of the first microcapsule at 40° C. for 30 minutes to obtain a first core material mixture; S3. Add the first core material mixture to the first shell material mixture, emulsify at 55° C., 600 rpm for 25 min, crosslink at 70° C., 400 rpm for 25 min, centrifuge, wash with water, and dry to obtain a microcapsule self-healing material.

[0026] Example 3 A microcapsule self-repairing material for concrete structure cracks, comprising a first microcapsule; The first microcapsule includes a core material and a shell material in a mass ratio of 1.1:1; The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde prepolymer; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 10 parts of latent curing agent; The latent curing agent includes 2-ethyl-4-methylimidazole and dicyandiamide in a mass ratio of 1:9; The preparation method of the microcapsule self-repairing material for concrete structure cracks comprises the following steps: S1, mixing the shell material raw materials of the first microcapsule, adjusting the pH to 8.5, stirring at 300 rpm for 15 min, to obtain a first shell material mixture; S2, stirring and mixing the core material raw materials of the first microcapsule at 40° C. for 30 minutes to obtain a first core material mixture; S3. Add the first core material mixture to the first shell material mixture, emulsify at 55° C., 600 rpm for 25 min, crosslink at 70° C., 400 rpm for 25 min, centrifuge, wash with water, and dry to obtain a microcapsule self-healing material.

[0027] Example 4 The difference between this embodiment and embodiment 3 is that the latent curing agent includes 2-ethyl-4-methylimidazole and dicyandiamide in a mass ratio of 9:1.

[0028] Example 5 The only difference between this embodiment and embodiment 3 is that the latent curing agent includes 2-ethyl-4-methylimidazole and dicyandiamide in a mass ratio of 4:1.

[0029] Example 6 The difference between this embodiment and embodiment 3 is that the latent curing agent includes 2-ethyl-4-methylimidazole and dicyandiamide in a mass ratio of 1:4.

[0030] Example 7 A microcapsule self-repairing material for concrete structure cracks, comprising a first microcapsule and a second microcapsule; The second microcapsule includes a core material and a shell material in a mass ratio of 1.1:1: The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde prepolymer; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 3 parts of calcium humate; The first microcapsule includes a core material and a shell material in a mass ratio of 1.1:1: The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde prepolymer; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 10 parts of latent curing agent; The latent curing agent includes 2-ethyl-4-methylimidazole and dicyandiamide in a mass ratio of 1:4; The preparation method of the microcapsule self-repairing material for concrete structure cracks comprises the following steps: S1, mixing the shell material raw materials of the first microcapsule, adjusting the pH to 8.5, stirring at 300 rpm for 15 min, to obtain a first shell material mixture; S2, stirring and mixing the core material raw materials of the first microcapsule at 40° C. for 30 minutes to obtain a first core material mixture; S3, adding the first core material mixture to the first shell material mixture, emulsifying at 55° C. and 600 rpm for 25 min, cross-linking at 70° C. and 400 rpm for 25 min, centrifuging, washing with water, and drying to obtain first microcapsules; S4, mixing the shell material raw materials of the second microcapsule, adjusting the pH to 8.5, and stirring at 300 rpm for 15 min to obtain a second shell material mixture; S5, stirring and mixing the core material raw materials of the second microcapsule at 40° C. for 30 min to obtain a second core material mixture; S6, adding the second core material mixture to the second shell material mixture, emulsifying at 55° C. and 600 rpm for 25 min, crosslinking at 70° C. and 400 rpm for 25 min, centrifuging, washing with water, and drying to obtain second microcapsules; S7, mixing the first microcapsule and the second microcapsule to obtain a microcapsule self-healing material.

[0031] Example 8 A microcapsule self-repairing material for concrete structure cracks, comprising a first microcapsule and a second microcapsule; The second microcapsule includes a core material and a shell material in a mass ratio of 1.1:1: The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde prepolymer; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 6 parts of calcium humate; The first microcapsule includes a core material and a shell material in a mass ratio of 1.1:1: The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde prepolymer; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 10 parts of latent curing agent; The latent curing agent includes 2-ethyl-4-methylimidazole and dicyandiamide in a mass ratio of 1:4; The preparation method of the microcapsule self-repairing material for concrete structure cracks comprises the following steps: S1, mixing the shell material raw materials of the first microcapsule, adjusting the pH to 8.5, stirring at 300 rpm for 15 min, to obtain a first shell material mixture; S2, stirring and mixing the core material raw materials of the first microcapsule at 40° C. for 30 minutes to obtain a first core material mixture; S3, adding the first core material mixture to the first shell material mixture, emulsifying at 55° C. and 600 rpm for 25 min, cross-linking at 70° C. and 400 rpm for 25 min, centrifuging, washing with water, and drying to obtain first microcapsules; S4, mixing the shell material raw materials of the second microcapsule, adjusting the pH to 8.5, and stirring at 300 rpm for 15 min to obtain a second shell material mixture; S5, stirring and mixing the core material raw materials of the second microcapsule at 40° C. for 30 min to obtain a second core material mixture; S6, adding the second core material mixture to the second shell material mixture, emulsifying at 55° C. and 600 rpm for 25 min, crosslinking at 70° C. and 400 rpm for 25 min, centrifuging, washing with water, and drying to obtain second microcapsules; S7, mixing the first microcapsule and the second microcapsule to obtain a microcapsule self-healing material.

[0032] Example 9 The only difference between this embodiment and embodiment 8 is that calcium humate is replaced by calcium alginate.

[0033] Example 10 The only difference between this embodiment and embodiment 8 is that calcium humate is replaced by chitosan.

[0034] Comparative Example 1 The difference between this comparative example and Example 3 is that the latent curing agent is 2-ethyl-4-methylimidazole.

[0035] Comparative Example 2 The difference between this comparative example and Example 3 is that the latent curing agent is dicyandiamide.

[0036] Experimental example The microcapsule self-repairing materials prepared in Examples 1 to 10 and Comparative Examples 1 to 2 were respectively mixed into concrete (Portland cement and quartz sand) to prepare concrete. The anti-seepage pressure ratio test was carried out and the anti-seepage pressure recovery rate of the concrete after self-repair of water pressure damage was calculated according to GB 18445-2012 "Cement-based permeable crystalline waterproof material" and T / CECS 913-2021 "Standard for Test Method for Self-repairing Performance of Cement Concrete". The results are shown in Table 1 below.

[0037] Table 1 Performance test results

[0038] Compared with Comparative Examples 1-2, the microcapsule self-repairing materials prepared in Examples 1-10 have better self-repairing effect on concrete cracks, indicating that the use of latent curing agents using amine compounds or imidazole compounds and compounding with dicyandiamide compounds improves the self-repairing performance of the capsule self-repairing materials on concrete cracks.

[0039] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microcapsule self-repairing material for concrete structure cracks, characterized in that: comprising a first microcapsule; The first microcapsule comprises a core material and a shell material in a mass ratio of 1.1 to 2.5:1; The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde compound; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin, 8-12 parts of latent curing agent; The latent curing agent comprises component A and a dicyandiamide compound in a mass ratio of 1:9 to 9:1; The component A includes one or two of modified amine compounds and imidazole compounds.

2. The microcapsule self-repairing material for concrete structure cracks according to claim 1, characterized in that: The urea-formaldehyde compound includes one of a urea-formaldehyde prepolymer and a polyurea-formaldehyde monomer; The modified amine compound includes one or more of aromatic modified amines, aliphatic modified amines, and alicyclic modified amines; The imidazole compound includes one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole and imidazole complex.

3. The microcapsule self-repairing material for concrete structure cracks according to claim 1, characterized in that: The dicyanamide-based compound includes one or more of dicyandiamide, modified dicyandiamide, dicyandiamide complex, and substituted dicyandiamide derivatives.

4. The microcapsule self-repairing material for concrete structure cracks according to claim 1, characterized in that: The latent curing agent comprises component A and a dicyandiamide compound in a mass ratio of 1:4 to 4:

1.

5. The microcapsule self-repairing material for concrete structure cracks according to claim 1, characterized in that: The raw materials of the shell material also include the following components: pH regulator and silane coupling agent.

6. The microcapsule self-repairing material for concrete structure cracks according to claim 1, characterized in that: The raw materials of the core material also include at least one of the following components: filler, toughening agent, defoaming agent, and dispersant.

7. The microcapsule self-repairing material for concrete structure cracks according to claim 1, characterized in that: The epoxy resin includes one of bisphenol A epoxy resin and bisphenol F epoxy resin; The epoxy equivalent of the epoxy resin is 180-220 g / eq.

8. The microcapsule self-repairing material for concrete structure cracks according to claim 1, characterized in that: Also included is a second microcapsule; the second microcapsule includes a core material and a shell material in a mass ratio of 1.1 to 2.5:1; The raw materials of the shell material include the following components in parts by weight: 100 parts of urea-formaldehyde compound; The raw materials of the core material include the following components in parts by weight: 100 parts of epoxy resin and 3-6 parts of humate.

9. The method for preparing a microcapsule self-repairing material for concrete structure cracks according to claim 8, characterized in that: The following steps are involved: S1, mixing the shell material raw materials of the first microcapsules, adjusting the pH to 8-9, and obtaining a first shell material mixture; S2, mixing the core material raw materials of the first microcapsules to obtain a first core material mixture; S3, adding the first core material mixture to the first shell material mixture for emulsification, cross-linking, and post-treatment to obtain a first microcapsule; S4, mixing the shell material raw materials of the second microcapsules, adjusting the pH to 8-9, and obtaining a second shell material mixture; S5, mixing the core material raw materials of the second microcapsules to obtain a second core material mixture; S6, adding the second core material mixture to the second shell material mixture for emulsification, cross-linking, and post-treatment to obtain second microcapsules; S7, mixing the first microcapsule and the second microcapsule to obtain a microcapsule self-healing material.

10. The use of a microcapsule self-repairing material for concrete structure cracks according to any one of claims 1 to 8 or a microcapsule self-repairing material prepared by the preparation method according to claim 9 in concrete, characterized in that: The mass of the microcapsule self-repairing material is 2% to 5% of the mass of the concrete.

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