阅读说明：本技术 一种耐久性自修复建筑涂料及制备方法 (Durable self-repairing building coating and preparation method thereof ) 是由 陈庆 杨洁 于 2019-09-27 设计创作，主要内容包括：本发明提出一种耐久性自修复建筑涂料,所述建筑涂料是由微胶囊产物、发酵滤渣、水性树脂、氧化铝浆料、钛白粉、纳米二氧化硅、大豆卵磷脂和去离子水搅拌而制得；所述微胶囊产物是由羟乙基纤维素、丙烯酸、引发剂和交联剂接枝反应并粉碎制成粒度产物,然后加入三聚氰胺、甲醛、三乙醇胺、吐温80和水为原料得到的乳液中反应而制得；所述发酵滤渣由碳酸钙和芽孢杆菌菌液密封发酵而制得。本发明提供的涂料中含有自修复功能的微胶囊产物和发酵滤渣,可在涂层受损后吸水促进微胶囊内共聚物的膨胀和形成碳酸钙结晶,起到填充裂缝的作用,同时发酵滤渣赋予了抑制涂层裂缝扩展的能力,所得涂料具有耐久性自修复的效果。(the invention provides a durable self-repairing building coating which is prepared by stirring a microcapsule product, fermentation filter residues, water-based resin, alumina slurry, titanium dioxide, nano silicon dioxide, soybean lecithin and deionized water; the microcapsule product is prepared by performing graft reaction on hydroxyethyl cellulose, acrylic acid, an initiator and a cross-linking agent, crushing the mixture to prepare a particle size product, and then adding melamine, formaldehyde, triethanolamine, tween 80 and water into emulsion obtained by taking the raw materials as raw materials to react; the fermentation filter residue is prepared by sealing and fermenting calcium carbonate and bacillus liquid. The coating provided by the invention contains microcapsule products with self-repairing function and fermentation filter residues, and can absorb water to promote the expansion of the copolymer in the microcapsule and form calcium carbonate crystals after the coating is damaged, so that the effect of filling cracks is achieved, meanwhile, the fermentation filter residues endow the coating with the capability of inhibiting the crack expansion of the coating, and the obtained coating has the effect of durable self-repairing.)

1. The durable self-repairing building coating is characterized by being prepared by stirring a microcapsule product, fermentation filter residues, water-based resin, alumina slurry, titanium dioxide, nano silicon dioxide, soybean lecithin and deionized water; the microcapsule product is prepared by performing graft reaction on hydroxyethyl cellulose, acrylic acid, an initiator and a cross-linking agent, crushing the mixture to prepare a particle size product, and then adding melamine, formaldehyde, triethanolamine, tween 80 and water into emulsion obtained by taking the raw materials as raw materials to react; the fermentation filter residue is prepared by sealing and fermenting calcium carbonate and bacillus liquid, and the specific preparation method comprises the following steps:

(1) Putting hydroxyethyl cellulose into a container, adding a proper amount of 0.2mol/L NaOH solution, stirring in a water bath at 45 ℃ for 30min, slowly adding acrylic acid into the container, sequentially adding an initiator and a cross-linking agent, heating for reaction for a period of time, washing and filtering a product, drying in a drying oven at 60 ℃ to constant weight, crushing, and sieving with a 100-mesh sieve to obtain a particle-size product, namely the water absorbent;

(2) uniformly mixing melamine and formaldehyde solution according to the mass ratio of 1:3, adjusting the pH value to 8-9 by using triethanolamine aqueous solution with the mass ratio of 20-25%, stirring and heating to 60 ℃, reacting until the melamine is completely dissolved, then diluting by using water with the same volume as the formaldehyde, continuously reacting for 10min to obtain aqueous solution of melamine resin prepolymer, keeping the temperature of the solution at 70 ℃, then dripping into water containing tween 80 for ultrasonic emulsification to obtain pre-polymerized emulsion, then adding a granularity product into the pre-polymerized emulsion, adjusting the pH value of the system to 4-5 by using hydrochloric acid solution, stirring and reacting, then cooling, filtering, washing and drying to obtain a microcapsule product;

(3) Mixing calcium carbonate and bacillus liquid, placing the mixture in a fermentation tank, sealing the fermentation tank for fermentation, and filtering the mixture after the fermentation is finished to obtain fermentation filter residues;

(4) Adding the microcapsule product, the fermentation filter residue, the water-based resin, the alumina slurry, the titanium dioxide, the nano-silica, the soybean lecithin and the deionized water into a stirrer, and uniformly mixing and stirring to obtain the durable self-repairing building coating.

2. The durable self-repairing architectural coating of claim 1, wherein the aqueous resin is one or a combination of more than two of phenolic resin, acrylic resin, epoxy resin, polyester resin and polyurethane resin.

3. the durable self-repairing architectural coating of claim 1, wherein the crosslinker is N, N-methylenebisacrylamide.

4. the durable self-repairing architectural coating of claim 1, wherein the initiator is an azo initiator, and the azo initiator is one of azobisisobutyramidine hydrochloride, azobisisobutyrimidazoline hydrochloride, and azobisisobutyronitrile formamide.

5. The durable self-repairing architectural coating of claim 1, wherein the temperature of the heating reaction in step (1) is 45-50 ℃ and the reaction time is 1-3 hours.

6. the durable self-repairing building coating as claimed in claim 1, wherein in the step (1) of preparing the water absorbent, the mass ratio of the NaOH solution to the hydroxyethyl cellulose to the acrylic acid to the initiator to the cross-linking agent is 100:10-30:15-35:2-4: 1-3.

7. The durable self-repairing building coating of claim 1, wherein in the preparation of the emulsion in the step (2), the mass ratio of the water, tween 80 and the aqueous solution of the melamine resin prepolymer is 100:1-4: 40-55; the ultrasonic frequency of the ultrasonic emulsification is 40-60kHz, and the ultrasonic treatment is carried out for 30-40 min.

8. The durable self-repairing architectural coating of claim 1, wherein in the preparation of the microcapsule product in the step (2), the mass ratio of the particle size product to the pre-polymerization liquid is 1: 2; the stirring speed of the stirring reaction was 450rpm, and the stirring was carried out for 2.5 hours.

9. The durable self-repairing building coating of claim 1, wherein in the preparation of the fermentation filter residue in the step (3), the mass ratio of calcium carbonate to bacillus liquid is 3: 1; the temperature of the sealed fermentation is 35-45 ℃, and the fermentation time is 1 week.

10. The durable self-repairing building coating of claim 1, wherein in the step (4) of coating preparation, the mass ratio of the microcapsule product, the fermentation residue, the water-based resin, the alumina slurry, the titanium dioxide, the nano-silica, the soybean lecithin and the deionized water is 5-10:5-8:20-30:5-10:3-55:3-5:1-3: 40-60.

Technical Field

The invention relates to the technical field of building coatings, in particular to a durable self-repairing building coating and a preparation method thereof.

background

the coating is used as a polymer-based composite material and is widely applied to a plurality of fields such as buildings, aerospace, traffic, electronics, sports, military supplies and the like due to the advantages of light weight, high strength, excellent mechanical property, good corrosion resistance, good electrical property and the like. However, polymer-based composites have one major drawback: such composites are susceptible to damage from impact during processing and use. In addition to material failure from intense impact, more common is material micro-damage (microcracks), which is often difficult to detect visually. At this point, the material surface may not see any abnormalities, but the strength of the material has been greatly reduced. The microcracks cause the mechanical strength of the composite material to be reduced, and once the microcracks are generated in the polymer material, the integrity of the material is seriously damaged, even the integral damage of the material is caused.

because the coating is generally made of composite fibers, polymer solution, stone powder, a thickening agent and other materials, the coating is directly exposed to the sun, and the phenomena of drying crack and peeling appear after long-term use, so that the appearance of the building outer wall is influenced, the coating is exposed to the sun for a long time to form cracks, cracks are formed, the cracks continuously extend, the wall structure is unstable, and the wall collapses in severe cases.

researches show that the organism has a self-healing function after being damaged, and if the self-healing function of the biomaterial can be reproduced on the composite material, the biomaterial has high application value. With the inspiration, scientists establish a self-repairing model of the material, so that damages to the material, particularly the damages which cannot be detected inside the material can be repaired to a certain degree without using an additional repairing material, and the self-repairing model has important significance for maintaining the mechanical strength of the material, eliminating hidden dangers and prolonging the service life. The concept of intelligent material with self-diagnosis and self-repair functions is provided by the U.S. military in the middle of the 80 th century, and is rapidly becoming the focus of research in various countries. The self-repairing technology is applied to the field of coatings, namely the self-repairing coatings are generated.

the self-repairing coating is a coating with a self-repairing function after a coating is damaged or a coating with a self-repairing function under certain conditions. In recent years, the coating technology is closely linked with the development of material science, various functional coatings are continuously developed along with the continuous progress of the material science, and under the background, the self-repairing coating is rapidly developed in theoretical research and practical application. The self-repairing coating can be roughly divided into 3 types according to different repairing mechanisms: a repair agent-releasing self-healing coating; reversible chemical/physical reaction self-healing coatings and other types.

chinese invention patent application No. 201610753294.4 discloses a waterproof coating for buildings, which comprises the following raw materials in parts by weight: 21-32 parts of epoxy resin, 1-5 parts of polyamide resin, 2-4 parts of butylated amino resin, 5-9 parts of ABS resin, 2-3 parts of phenolic resin, 15-23 parts of Portland cement, 8-15 parts of asphalt, 2-7 parts of ethyl acetate, 16-26 parts of xylene, 11-16 parts of bentonite, 2-5 parts of nano titanium dioxide, 1-2 parts of toughening agent, 2-4 parts of defoaming agent, 7-10 parts of flatting agent and 5-9 parts of drier. Chinese patent application No. 201811480065.5 discloses a microcapsule self-repairing anticorrosive coating and a preparation method thereof. The coating is composed of silicon dioxide microcapsules with built-in corrosion inhibitors in silicon-based emulsion; the method comprises the steps of mixing an ethyl orthosilicate cyclohexane solution and a corrosion inhibitor, adjusting the pH value of the mixture by using acid, stirring for reaction, filtering reaction liquid, adding a sodium dodecyl benzene sulfonate aqueous solution into the obtained organic-inorganic hybrid emulsion, stirring, sequentially carrying out solid-liquid separation, washing and drying on the obtained water-in-oil type core material emulsion to obtain a silicon dioxide microcapsule coated with the corrosion inhibitor, adding a metal platinum catalyst into silicon oil, stirring to obtain a silicon-based emulsion, mixing the silicon dioxide microcapsule coated with the corrosion inhibitor and the silicon-based emulsion, adding maleic anhydride monodecane into the mixture, and stirring for reaction to obtain the target product.

In order to solve the problems of cracking, falling off and the like of a coating layer of a common architectural coating under the influence of external environments such as sunlight and the like for a long time, a novel architectural coating needs to be provided, so that the self-repairing property of the coating is effectively realized, and the durability of the coating is improved.

Disclosure of Invention

Aiming at the problem that the coating is easy to crack and fall off when the conventional building coating is in the sun for a long time, the invention provides a durable self-repairing building coating of the building coating, so that the durable self-repairing effect of the coating is effectively realized.

in order to solve the problems, the invention adopts the following technical scheme:

A durable self-repairing building coating is prepared by stirring a microcapsule product, fermentation filter residues, water-based resin, alumina slurry, titanium dioxide, nano silicon dioxide, soybean lecithin and deionized water; the microcapsule product is prepared by performing graft reaction on hydroxyethyl cellulose, acrylic acid, an initiator and a cross-linking agent, crushing the mixture to prepare a particle size product, and then adding melamine, formaldehyde, triethanolamine, tween 80 and water into emulsion obtained by taking the raw materials as raw materials to react; the fermentation filter residue is prepared by sealing and fermenting calcium carbonate and bacillus liquid. The preparation method comprises the following steps:

(1) Putting hydroxyethyl cellulose into a container, adding a proper amount of 0.2mol/L NaOH solution, stirring in a water bath at 45 ℃ for 30min, slowly adding acrylic acid into the container, sequentially adding an initiator and a cross-linking agent, heating for reaction for a period of time, washing and filtering a product, drying in a drying oven at 60 ℃ to constant weight, crushing, and sieving with a 100-mesh sieve to obtain a particle-size product, namely the water absorbent;

(2) Uniformly mixing melamine and formaldehyde solution according to the mass ratio of 1:3, adjusting the pH value to 8-9 by using triethanolamine aqueous solution with the mass ratio of 20-25%, stirring and heating to 60 ℃, reacting until the melamine is completely dissolved, then diluting by using water with the same volume as the formaldehyde, continuously reacting for 10min to obtain aqueous solution of melamine resin prepolymer, keeping the temperature of the solution at 70 ℃, then dripping into water containing tween 80 for ultrasonic emulsification to obtain pre-polymerized emulsion, then adding a granularity product into the pre-polymerized emulsion, adjusting the pH value of the system to 4-5 by using hydrochloric acid solution, stirring and reacting, then cooling, filtering, washing and drying to obtain a microcapsule product;

(3) Mixing calcium carbonate and bacillus liquid, placing the mixture in a fermentation tank, sealing the fermentation tank for fermentation, and filtering the mixture after the fermentation is finished to obtain fermentation filter residues;

(4) Adding the microcapsule product, the fermentation filter residue, the water-based resin, the alumina slurry, the titanium dioxide, the nano-silica, the soybean lecithin and the deionized water into a stirrer, and uniformly mixing and stirring to obtain the durable self-repairing building coating.

Preferably, the aqueous resin is one or a combination of two or more of phenolic resin, acrylic resin, epoxy resin, polyester resin and polyurethane resin.

Preferably, the crosslinking agent is N, N-methylene bisacrylamide.

Preferably, the initiator is an azo initiator.

Further preferably, the azo initiator is one of azobisisobutyramidine hydrochloride, azobisisobutyrimidazoline hydrochloride and azobisisobutyronitrile formamide.

preferably, the temperature of the heating reaction in the step (1) is 45-50 ℃, and the reaction lasts for 1-3 h.

Preferably, in the step (1), during the preparation of the water absorbent, the mass ratio of the NaOH solution to the hydroxyethyl cellulose to the acrylic acid to the initiator to the cross-linking agent is 100:10-30:15-35:2-4: 1-3.

Preferably, in the preparation of the emulsion in the step (2), the mass ratio of the water, the tween 80 and the aqueous solution of the melamine resin prepolymer is 100:1-4: 40-55.

Preferably, the ultrasonic frequency of the ultrasonic emulsification in the step (2) is 40-60kHz, and the ultrasonic treatment is 30-40 min.

preferably, in the preparation of the microcapsule product in the step (2), the mass ratio of the particle size product to the pre-polymerization liquid is 1: 2.

Preferably, the stirring speed of the stirring reaction in the step (2) is 450rpm, and the stirring is carried out for 2.5 h.

Preferably, in the preparation of the fermentation filter residue in the step (3), the mass ratio of the calcium carbonate to the bacillus liquid is 3: 1.

Preferably, the temperature of the sealed fermentation in the step (3) is 35-45 ℃, and the fermentation time is 1 week.

Preferably, in the step (4), in the preparation of the coating, the mass ratio of the microcapsule product, the fermentation filter residue, the water-based resin, the alumina slurry, the titanium dioxide, the nano-silica, the soybean lecithin and the deionized water is 5-10:5-8:20-30:5-10:3-55:3-5:1-3: 40-60.

It is known that polymer coatings are constantly affected by external forces, and the internal structure and properties of the polymer coatings are easily changed, so that microcracks occur to different degrees. The micro-cracks inside the coating are continuously generated and gathered, finally, the macroscopic cracking and breakage are caused, so that the mechanical property of the coating is greatly damaged, and the micro-cracks generated inside are difficult to repair from the outside through the prior art. Therefore, self-repairing coatings which are automatically detected, identified and repaired inside are produced. Among them, the self-repairing coating filled with microcapsules of external-aid type becomes the focus and hot spot of the present research.

The invention firstly uses acrylic acid and hydroxyethyl cellulose as raw materials, adds initiator and cross-linking agent under alkaline condition to obtain polymer product which is used as core material of microcapsule and is a water absorbent with higher water absorption capacity.

Further, the invention takes melamine, triethanolamine and formaldehyde as raw materials, and takes melamine-formaldehyde prepolymer as the capsule wall material of the microcapsule to prepare the microcapsule product with the self-repairing function as an important component of the self-repairing coating.

the microcapsule product obtained by the process has high water absorption capacity, when the coating is damaged, the microcapsule is broken, and the copolymer in the capsule can quickly absorb the water in the air to expand and block the crack.

Furthermore, the calcium carbonate and the bacillus liquid are mixed and then are sealed and fermented to obtain fermentation filter residues, water enters the fermentation filter residues through the water absorption capacity of the microcapsules, bacterial spores are activated, calcium carbonate crystals are promoted to continuously grow, crack expansion of the coating is inhibited, and the effect of durability self-repairing is achieved.

The invention provides a durable self-repairing building coating and a preparation method thereof, a certain amount of hydroxyethyl cellulose is weighed and put into a container, a proper amount of NaOH solution is added, the container is placed into a water bath for stirring, acrylic acid is slowly added into the container, and then an initiator and a cross-linking agent are sequentially added; after heating and reacting for a period of time, washing and filtering the product, putting the product into an oven to be dried to constant weight, crushing and sieving the product to obtain a granularity product; mixing melamine with a formaldehyde solution, stirring and heating to react the mixture until the melamine is completely dissolved by using a triethanolamine aqueous solution, diluting the mixture by using water with the same volume as the formaldehyde, and continuously reacting to obtain an aqueous solution of a melamine resin prepolymer; maintaining the temperature of the solution, dripping the solution into water containing Tween 80, performing ultrasonic emulsification, adding a particle size product into the emulsion, adjusting the pH value with a hydrochloric acid solution for reaction, cooling, filtering, washing and drying to obtain a microcapsule product; mixing calcium carbonate and bacillus liquid, placing the mixture in a fermentation tank, sealing and fermenting, and filtering after fermentation to obtain fermentation filter residues; uniformly stirring the microcapsule product, the fermentation filter residue, the water-based resin, the alumina slurry, the titanium dioxide, the nano-silica, the soybean lecithin and the deionized water in a stirrer to prepare the durable self-repairing building coating. The coating provided by the invention contains microcapsule products with self-repairing function and fermentation filter residues, and can absorb water to promote the expansion of the copolymer in the microcapsule and form calcium carbonate crystals after the coating is damaged, so that the effect of filling cracks is achieved, meanwhile, the fermentation filter residues endow the coating with the capability of inhibiting the crack expansion of the coating, and the obtained coating has the effect of durable self-repairing.

compared with the prior art, the durable self-repairing building coating provided by the invention has the outstanding characteristics and excellent effects that:

1. The microcapsule product with the self-repairing function in the building coating has strong water absorption capacity, the microcapsule can be broken after a coating is damaged, the copolymer in the capsule can quickly absorb water to expand to block cracks, and simultaneously, calcium carbonate crystals can be formed to play a role in filling the cracks.

2. the fermentation filter residue in the self-repairing coating disclosed by the invention enables calcium carbonate crystals to continuously grow, and has the capability of inhibiting the crack expansion of the coating, so that the coating achieves the effect of durable self-repairing.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.