Concrete negative surface treating agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of functional coatings, and particularly relates to a concrete negative surface treating agent and a preparation method and application thereof, and the concrete negative surface treating agent comprises the following components in parts by mass: 450-550 parts of filler, 450-550 parts of water, 15-25 parts of graft modified starch ether, 0.3-40 parts of hydration inhibitor, 98-102 parts of styrene-acrylic emulsion, 1-6 parts of inorganic pigment, 0.5-0.7 part of antirust agent, 0.1-0.7 part of defoaming agent, 0.3-0.8 part of drier and 0.1-0.3 part of preservative. The prepared surface treating agent is sprayed on the inner surface of a mold, concrete can lose efficacy for a long time on the inner surface of the mold, the sprayed surface treating agent has good hardness and anti-vibration performance after forming a film, meanwhile, the weather resistance is good, and the effect that the depth of textures is controllable can be achieved by adjusting the raw material ratio.

Description

Technical Field

[0001] The invention belongs to the technical field of functional coatings, and in particular relates to a concrete negative surface treatment agent and a preparation method and application thereof. Background Art

[0002] Image concrete is one of the small buildings that is more in line with modern aesthetics. Pouring concrete into a mold to solidify and shape it is one of the methods for preparing image concrete. This process also requires spraying a layer of negative surface treatment agent on the mold surface to extend the setting and hardening time of the concrete. For example, CN110256964B discloses "a negative retarding coating for concrete and a preparation method thereof". Adhesives, retarders, fillers, and thickeners are mixed as main raw materials to form a negative retarding coating for concrete, which can be used for formwork to achieve the effect of retarding setting at the interface between concrete and formwork.

[0003] For example, CN111848215B discloses "a negative corrosion inhibitor capable of adjusting the water washing depth of exposed aggregate concrete and its application". A negative corrosion inhibitor is prepared with retarder and auxiliary materials as main raw materials, which realizes uniform washing of the surface of exposed aggregate concrete and can achieve the effect of a specific water washing depth.

[0004] However, in the actual application of concrete, it is inevitable to vibrate the mold to eliminate bubbles in the concrete and achieve a more homogeneous state. At this time, the coating sprayed on the inner surface of the mold will be wetting damaged, especially for image concrete prepared with printing paper. Due to vibration, the film layer of the printing paper is broken, resulting in the diffusion of the hydration inhibitor therein and pixelation of the image. In addition, the above-disclosed patents do not mention and solve the problem of the retarder coating falling off during vibration, the short retarding time and the uneven coating.

[0005] Therefore, it is urgent to develop a negative surface treatment agent for concrete that is easy to construct and simple in process, can inhibit the hydration of concrete for a long time, has a strong anti-vibration ability and good low-temperature film-forming property, and can be stably present on the mold surface. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a negative surface treatment agent for concrete, a preparation method and an application thereof. The surface treatment agent is sprayed on the inner surface of the mold to permanently reduce the strength of the contact between the concrete and the inner surface of the mold. The sprayed surface treatment agent has good hardness and anti-vibration performance after film formation, and good weather resistance. At the same time, the texture depth can be controlled by adjusting the raw material ratio.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] On the one hand, the present invention provides a negative surface treatment agent for concrete, comprising the following components by weight: 450-550 parts of filler, 450-550 parts of water, 15-25 parts of grafted modified starch ether, 0.3-40 parts of hydration inhibitor, 98-102 parts of styrene-acrylic emulsion, 1-6 parts of inorganic pigment, 0.5-0.7 parts of rust inhibitor, 0.1-0.7 parts of defoamer, 0.3-0.8 parts of drying agent and 0.1-0.3 parts of preservative.

[0009] The negative surface treatment agent of the present application can form a stable and wear-resistant film on the inner surface of the mold. This is due to the synergistic effect of the grafted modified starch ether, the styrene acrylic emulsion and the filler. The grafted modified starch ether can make the paint film have better anti-sagging properties after the water in the coating gradually evaporates. In addition, the styrene acrylic emulsion and the filler can make the layer have better hardness and wear resistance, preventing the layer from falling off and the film from rupturing due to friction and vibration during the vibration process, resulting in the precipitation of hydration inhibitors, so that the pattern cannot present the expected effect, and blurring, deformation and the like occur. In addition, the effect of controllable image depth can be achieved by regulating the amount of hydration inhibitor added.

[0010] In some embodiments, the filler is any one of heavy calcium powder, mica powder and talc powder.

[0011] In some embodiments, the grafted modified starch ether is a starch and a compound shown in formula I

[0012]

[0013] It is prepared by Williamson reaction, wherein R1 and R2 are independently C1-C3 alkyl groups, R3 is H, OH or CH3, and n is an integer of 1-4.

[0014] The applicant found in the research that the negative surface treatment agent prepared by using conventional starch ether, styrene acrylic emulsion and filler as the main raw materials has poor weather resistance, especially in the extreme cold weather in Northeast China, the image prepared is pixelated and unclear, while the grafted modified starch ether prepared by the present application can make the image concrete still maintain clear image in extremely cold weather. The reason may be that the branch chain of the starch ether of the present invention has a long ether bond structure, which can not only increase the viscosity of the paint film and improve the anti-sagging performance, but also because the long ether bond has a weak polarity, it can reduce the van der Waals force and hydrogen bonding between molecules in the system, increase the fluidity and flexibility of the molecular chain at low temperature, and prevent the styrene acrylic emulsion from becoming brittle at low temperature and difficult to form a film, resulting in pixelated image.

[0015] In addition, the grafted modified starch ether of the present application contains a tertiary amine structure, which can form a coordination bond with the surface of the metal mold and thus be firmly adsorbed on the mold surface to form a stable film layer. At the same time, regulating the length of the alkyl chains of R1 and R2 can prevent the long-chain alkyl from having large steric hindrance, which makes subsequent reactions difficult.

[0016] In some embodiments, when R3 is H or CH3, n=an integer of 1 to 2; when R3 is OH, n=an integer of 1 to 4.

[0017] In some embodiments, the method for preparing the grafted modified starch ether specifically comprises the following steps:

[0018] A1. Mix cyanuric chloride with deionized water, and then add the compound shown in formula II

[0019]

[0020] Adjust the system pH to 4-5, stir at room temperature for 22-24 hours, and obtain compound X by column chromatography after the reaction is completed;

[0021] A2, the compound shown in formula III

[0022]

[0023] Mix with solvent, add sodium hydroxide, heat to 60-70°C and stir for 25-35 minutes, then add compound X in step A1, heat to 100-110°C and stir for 8-9 hours. After the reaction, adjust the pH of the system to neutral in an ice water bath, filter, concentrate and dry to obtain the compound shown in formula I

[0024]

[0025] A3. Mix starch and dimethyl sulfoxide and stir, add sodium hydroxide, heat to 70-80°C and stir for 30-40 min, then add the compound of formula I in step A2, heat to 100-110°C and stir for 11-13 h. After the reaction, adjust the pH of the system to neutral with dilute hydrochloric acid solution in an ice-water bath, filter, concentrate and dry to obtain grafted modified starch ether.

[0026] In some embodiments, in step A1, the molar ratio of cyanuric chloride to the compound represented by formula II is 1:(0.2-0.3).

[0027] Preferably, in step A1, the molar ratio of cyanuric chloride to the compound represented by formula II is 1:0.25.

[0028] The present application adjusts the molar ratio of cyanuric chloride to the compound shown in formula II so that one of the chlorine compounds can react with the compound shown in formula II, thereby preventing the grafted modified starch ether obtained from reacting multiple chlorine compounds with the compound shown in formula II from being unable to effectively improve the low temperature resistance of the styrene-acrylic emulsion.

[0029] In some embodiments, in step A2, the molar ratio of compound X to the compound represented by formula III is 1:(0.9-1).

[0030] Preferably, in step A2, the molar ratio of compound X to the compound represented by formula III is 1:0.95.

[0031] The present application can prevent both chlorines from reacting with the compound shown in Formula III, resulting in no active sites for grafting with starch, by regulating the molar ratio of compound X to the compound shown in Formula III.

[0032] In some embodiments, the method for preparing the hydration inhibitor comprises the following steps:

[0033] (1) Add formaldehyde solution dropwise to 8-hydroxyquinoline, then add concentrated hydrochloric acid and stir to dissolve, continue to introduce hydrogen chloride gas into the system until no more precipitation is produced to stop the reaction, filter, rinse with ether, and dry to obtain compound A;

[0034] (2) Under an inert protective gas atmosphere, compound A in step (1), 1,2-di(2-chloroethoxy)ethane, potassium iodide and an acid binding agent are added to a solvent, the temperature is raised to 110-120° C. and stirred at a constant temperature for 46-50 hours. After the reaction is completed, the mixture is concentrated under reduced pressure, extracted, and the organic phases are combined and dried under reduced pressure and subjected to column chromatography to obtain a compound represented by formula IV

[0035]

[0036] (3) Mix the compound represented by formula IV in step (2) with N,N-dimethylaminomethanediphosphonic acid, add the solvent, heat to 100-120° C. and stir for 2-4 hours. After the reaction is completed, cool to room temperature, filter, wash with ethyl acetate, and concentrate and dry under reduced pressure to obtain a hydration inhibitor.

[0037] In some embodiments, in step (1), the mass concentration of the formaldehyde solution is 30-40%.

[0038] In some embodiments, in step (1), the volume ratio of the mass of 8-hydroxyquinoline to the formaldehyde solution is 1:(3-4).

[0039] In some embodiments, in step (2), the molar ratio of compound A, 1,2-bis(2-chloroethoxy)ethane, potassium iodide and acid binding agent is 1:(0.5-0.6):(0.1-0.2):(1.2-1.4).

[0040] Preferably, in step (2), the molar ratio of compound A, 1,2-bis(2-chloroethoxy)ethane, potassium iodide and acid binding agent is 1:0.55:0.15:1.3.

[0041] In some embodiments, in step (3), the molar ratio of the compound represented by formula IV to N,N-dimethylaminomethanediphosphonic acid is 1:(2-2.2).

[0042] Preferably, in step (3), the molar ratio of the compound represented by formula IV to N,N-dimethylaminomethanediphosphonic acid is 1:2.1.

[0043] Another aspect of the present invention provides a method for preparing a concrete negative surface treatment agent, comprising the following steps:

[0044] S1. Mix half of the water with the hydration inhibitor, inorganic pigment and grafted modified starch ether and stir for 30 to 40 minutes to obtain material A;

[0045] S2, take the other half of the water and mix it with the filler, stirring and mixing for 20 to 30 minutes to obtain material B;

[0046] S3. Add material B in step S2 to material A in step S1, control the rotation speed to 300-500 r / min, add defoamer and continue stirring until no bubbles are generated, then add styrene acrylic emulsion, rust inhibitor, drying agent and preservative, stir for 1-1.5 hours, and obtain the concrete negative surface treatment agent.

[0047] The present application can prevent bubbles from being generated during stirring and thus reduce the quality of the product by regulating the rotation speed. At the same time, the final addition of the styrene-acrylic emulsion can encapsulate the grafted modified starch ether and the hydration inhibitor to form a microcapsule structure. In the initial stage of concrete pouring, the moisture in the concrete can be prevented from taking away the effective ingredients and causing image pixelation. In addition, the moisture in the concrete can gradually soften the styrene-acrylic emulsion film layer. After a certain period of time, the effective ingredients therein are slowly released and flow out, thereby preventing the concrete from hydrating.

[0048] On the other hand, the present invention provides an application of a negative surface treatment agent for concrete in the preparation of image concrete, comprising the following steps: spraying the negative surface treatment agent on the inner surface of a mold according to a pre-obtained pattern, drying at room temperature for 1 to 5 hours, pouring concrete into the mold, naturally curing the concrete after vibration to solidify and form, demolding and washing the concrete surface after forming to obtain image concrete.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The present invention adopts a filler, a grafted modified starch ether, a hydration inhibitor, a styrene acrylic emulsion, an inorganic pigment, a rust inhibitor, a defoamer, a drying agent and a preservative to prepare a concrete negative surface treatment agent. The surface treatment agent is sprayed on the inside of the mold, and then poured with concrete after drying. After smearing and cleaning, the image concrete can be obtained. The method for preparing the image concrete with the negative surface treatment agent is simple, and the strength of the contact between the concrete and the inner surface of the mold can be permanently invalidated. It also has strong vibration resistance and low temperature resistance, and has a wide range of applications.

[0051] (2) The hydration inhibitor of the present invention chelates calcium ions by means of polyphosphate groups and amine groups, so that the product produced by the chelation of calcium ions by the hydration inhibitor is more stable and not easy to decompose. In addition, the quaternary ammonium salt structure of the hydration inhibitor can generate charge attraction with concrete particles in water, coat the concrete surface, and give the concrete particles a certain lubrication and dispersion effect under the action of ether bonds. At the same time, the hydration inhibitor can form a relatively stable hydrogen bond with water, and form a hydration film on the concrete surface, thereby hindering the hydration of the concrete.

[0052] (3) The grafted modified starch ether of the present invention has a long ether bond structure in its side chain, which can not only increase the viscosity of the paint film and improve the anti-sagging performance, but also because the long ether bond has a weak polarity, it can reduce the van der Waals force and hydrogen bonding between molecules in the system, increase the fluidity and flexibility of the molecular chain at low temperatures, and prevent the styrene acrylic emulsion from becoming brittle and difficult to form a film at low temperatures, resulting in image pixelation. In addition, the tertiary amine structure therein can form a coordination bond with the surface of the metal mold, thereby firmly adsorbing on the mold surface to form a stable film layer. The length of the alkyl chain of R1 and R2 can be adjusted, on the one hand, to prevent the starch ether from being too hydrophobic and reducing the wrapping ability of the styrene acrylic emulsion, and on the other hand, to prevent the long-chain alkyl from being too sterically hindered, making subsequent reactions difficult to carry out. DETAILED DESCRIPTION

[0053] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0054] In the following preparation examples, embodiments and comparative examples, the number average molecular weight of starch is 45,000; heavy calcium powder is purchased from Lingshou Yongshun Mineral Products Processing Plant; styrene acrylic emulsion is purchased from Henan Tianchou Chemical Products Co., Ltd.; CAT150 drying agent is purchased from Guangdong Core New Materials Co., Ltd.; HTK-301 preservative is purchased from Shanghai Hongtu Industrial Co., Ltd.

[0055] Preparation Example 1

[0056] The preparation method of the hydration inhibitor comprises the following steps:

[0057] (1) 25 mL of a 35% formaldehyde solution was added dropwise to 50 mmol of 8-hydroxyquinoline at a rate of 10 mL / min, followed by the addition of 80 mL of 37 wt% concentrated hydrochloric acid, followed by stirring and dissolution, and hydrogen chloride gas was continuously introduced into the system until no precipitation was produced to stop the reaction, and the mixture was filtered, rinsed with ether, and dried to obtain compound A;

[0058] (2) Under N2 atmosphere, 50 mmol of compound A in step (1), 27 mmol of 1,2-di(2-chloroethoxy)ethane, 7.5 mmol of potassium iodide and 65 mmol of potassium carbonate were added to 90 mL of N,N-dimethylformamide, the temperature was raised to 115°C and stirred at constant temperature for 48 hours. After the reaction was completed, the mixture was concentrated under reduced pressure and extracted. The organic phases were combined and dried under reduced pressure and subjected to column chromatography to obtain a compound represented by Formula IV

[0059]

[0060] The NMR data of the compound represented by Formula IV are analyzed as follows: 1H NMR (500 MHz, DMSO-d6) δ8.78 (dd, J=5, 2.2 Hz, 1H, H of nitrogen adjacent position), 8.44–8.38 (m, 1H, H of nitrogen para position), 7.50 (dd, J=10, 4.3 Hz, 1H, H of nitrogen meta position), 7.40–7.34 (m, 1H, H of the halogen side of the benzene ring), 7.00 (d, J=10 Hz, 1H, H of the ether bond side of the benzene ring), 4.76 (s, 2H, H of the methylene adjacent position of the halogen), 4.23 (t, J=5.0 Hz, 2H, H of the methylene on the middle ether bond), 3.73 (t, J=5.0 Hz, 2H, H of the methylene on the middle ether bond), 3.63 (s, 2H, H of the methylene on the middle ether bond);

[0061] (3) Mix 50 mmol of the compound represented by formula IV in step (2) with 105 mmol of N,N-dimethylaminomethanediphosphonic acid, add 130 mL of N,N-dimethylformamide, heat to 110° C. and stir for 3 h. After the reaction, cool to 27° C., filter, wash with ethyl acetate, and concentrate and dry under reduced pressure to obtain a hydration inhibitor;

[0062] NMR data analysis of hydration inhibitor: 1H NMR (500MHz, Deuterium Oxide) δ8.74 (dd, J=5, 2.4Hz, 1H, H of the nitrogen element in the nitrogen heterocycle), 8.47 (dd, J=10, 2.1Hz, 1H, H of the nitrogen element in the nitrogen heterocycle), 7.51 (dd, J=10, 4.1Hz, 1H, H of the nitrogen element in the nitrogen heterocycle), 7.28-7.24 (m, 1H, H of the outer side of the benzene ring), 7.06 (d, J=105Hz, 1H, H of the inner side of the benzene ring) ,4.69 (ddp, J=15,9.8,1.5Hz,1H, H on the carbon connecting the two phosphate groups),4.37 (s,2H, H of the methylene group on the quaternary ammonium salt),4.28 (t,J=5.0Hz,2H, H of the methylene group on the ether bond),3.78 (t,J=5.0Hz,2H, H of the methylene group on the ether bond),3.70 (s,2H, H of the methylene group on the ether bond),3.45 (d,J=5Hz,6H, H of the methyl group).

[0063] Preparation Example 2

[0064] The preparation method of grafted modified starch ether specifically comprises the following steps:

[0065] A1. Mix 0.5 mol of cyanuric chloride with 900 mL of deionized water, then slowly add 0.1 mol of di-n-propylamine, adjust the pH of the system to 4 with 10 wt % sodium carbonate aqueous solution, stir at 27° C. for 23 h, and after the reaction is completed, obtain compound X by column chromatography.

[0066] A2, 0.5 mol of pentaethylene glycol was mixed with 1.2 L of deionized water, 0.25 mol of sodium hydroxide was added, the temperature was raised to 65 ° C and stirred for 30 min, and then 0.48 mol of compound X in step A1 was added, the temperature was raised to 105 ° C and stirred for 8.5 h. After the reaction was completed, the pH of the system was adjusted to 7 with 2 mol / L dilute hydrochloric acid solution in an ice water bath, and the mixture was filtered, concentrated and dried to obtain

[0067]

[0068] The NMR data of the compound represented by Formula I are analyzed as follows: 1H NMR (500 MHz, DMSO-d6) δ4.46 (t, J=5 Hz, 1H, H of methylene on ether bond), 3.76 (t, J=5 Hz, 1H, H of methylene on ether bond), 3.66-3.62 (m, 1H, H of methylene on ether bond), 3.60-3.56 (m, 6H, H of methylene on ether bond), 3.55-3.52 (m, 1H, H of methylene on ether bond), 3.49 (t, J=10 Hz, 2H, H of methylene on both sides of nitrogen), 1.70 (h, J=10 Hz, 2H, H of methylene on methyl), 0.93 (t, J=10 Hz, 3H, H of methyl);

[0069] A3. Mix 0.5 mol of starch and 12 g of dimethyl sulfoxide, add 0.4 mol of sodium hydroxide, heat to 75°C and stir for 35 min, then add 0.05 mol of the compound represented by formula I in step A2, heat to 105°C and stir for 12 h. After the reaction, adjust the pH of the system to 7 with 2 mol / L dilute hydrochloric acid solution in an ice-water bath, filter, concentrate and dry to obtain grafted modified starch ether.

[0070] Preparation Example 3

[0071] The preparation method of grafted modified starch ether has the same specific implementation as that of Preparation Example 2, except that an equal mole of di-n-hexylamine is used instead of di-n-propylamine.

[0072] Preparation Example 4

[0073] The preparation method of grafted modified starch ether is the same as that of Preparation Example 2, except that an equal molar amount of heptaethylene glycol monomethyl ether is used instead of pentaethylene glycol.

[0074] Preparation Example 5

[0075] The preparation method of grafted modified starch ether has the same specific implementation as that of Preparation Example 2, except that the amount of di-n-propylamine is 0.4 mol.

[0076] Preparation Example 6

[0077] The preparation method of grafted modified starch ether has the same specific implementation as that of Preparation Example 2, except that the amount of pentaethylene glycol is 1 mol.

[0078] Preparation Example 7

[0079] The preparation method of grafted modified starch ether is the same as that of Preparation Example 2, except that an equimolar amount of triethylene glycol monoethyl ether is used instead of pentaethylene glycol.

[0080] Example 1

[0081] A negative surface treatment agent for concrete comprises the following components in parts by weight: 500 parts of heavy calcium powder, 500 parts of water, 20 parts of grafted modified starch ether, 20 parts of hydration inhibitor, 100 parts of styrene acrylic emulsion, 3 parts of titanium dioxide, 0.6 parts of benzotriazole, 0.4 parts of dimethyl silicone oil, 0.5 parts of CAT150 drying agent and 0.2 parts of HTK-301 preservative.

[0082] Wherein, the grafted modified starch ether is prepared by Preparation Example 2, and the hydration inhibitor is prepared by Preparation Example 1.

[0083] The preparation method of the concrete negative surface treatment agent of this embodiment comprises the following steps:

[0084] S1, taking half of the water, mixing with the hydration inhibitor, titanium dioxide and grafted modified starch ether and stirring for 35 minutes to obtain material A;

[0085] S2, take the other half of the water and mix it with the heavy calcium powder, stirring for 25 minutes to obtain material B;

[0086] S3. Add material B in step S2 to material A in step S1, control the rotation speed to 400 r / min, add dimethyl silicone oil and continue stirring until no bubbles are generated, then add styrene acrylic emulsion, benzotriazole, CAT150 drying agent and HTK-301 preservative, stir for 1.3 hours, and obtain the concrete negative surface treatment agent.

[0087] Example 2

[0088] A negative surface treatment agent for concrete comprises the following components in parts by weight: 450 parts of heavy calcium powder, 450 parts of water, 15 parts of grafted modified starch ether, 0.3 parts of hydration inhibitor, 98 parts of styrene acrylic emulsion, 1 part of titanium dioxide, 0.5 parts of benzotriazole, 0.1 parts of dimethyl silicone oil, 0.3 parts of CAT150 drying agent and 0.1 parts of HTK-301 preservative.

[0089] Wherein, the grafted modified starch ether is prepared by Preparation Example 2, and the hydration inhibitor is prepared by Preparation Example 1.

[0090] The preparation method of the concrete negative surface treatment agent of this embodiment comprises the following steps:

[0091] S1. Take half of the water, mix with the hydration inhibitor, titanium dioxide and grafted modified starch ether and stir for 30 minutes to obtain material A;

[0092] S2, take the other half of the water and mix it with the heavy calcium powder, stirring for 20 minutes to obtain material B;

[0093] S3. Add material B in step S2 to material A in step S1, control the rotation speed to 500 r / min, add dimethyl silicone oil and continue stirring until no bubbles are generated, then add styrene acrylic emulsion, benzotriazole, CAT150 drying agent and HTK-301 preservative, stir for 1 hour, and obtain the concrete negative surface treatment agent.

[0094] Example 3

[0095] A negative surface treatment agent for concrete comprises the following components in parts by weight: 550 parts of heavy calcium powder, 550 parts of water, 25 parts of grafted modified starch ether, 40 parts of hydration inhibitor, 102 parts of styrene acrylic emulsion, 6 parts of titanium dioxide, 0.7 parts of benzotriazole, 0.7 parts of dimethyl silicone oil, 0.8 parts of CAT150 drying agent and 0.3 parts of HTK-301 preservative.

[0096] Wherein, the grafted modified starch ether is prepared by Preparation Example 2, and the hydration inhibitor is prepared by Preparation Example 1.

[0097] The preparation method of the concrete negative surface treatment agent of this embodiment comprises the following steps:

[0098] S1. Take half of the water, mix with the hydration inhibitor, titanium dioxide and grafted modified starch ether and stir for 40 minutes to obtain material A;

[0099] S2, take the other half of the water and mix it with the heavy calcium powder, stirring for 10 minutes to obtain material B;

[0100] S3. Add material B in step S2 to material A in step S1, control the rotation speed to 300 r / min, add dimethyl silicone oil and continue stirring until no bubbles are generated, then add styrene acrylic emulsion, benzotriazole, CAT150 drying agent and HTK-301 preservative, stir for 1.5 hours, and obtain the concrete negative surface treatment agent.

[0101] Example 4

[0102] A concrete negative surface treatment agent and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the grafted modified starch ether is prepared by Preparation Example 3.

[0103] Example 5

[0104] A concrete negative surface treatment agent and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the grafted modified starch ether is prepared by Preparation Example 4.

[0105] Example 6

[0106] A concrete negative surface treatment agent and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the grafted modified starch ether is prepared by Preparation Example 5.

[0107] Example 7

[0108] A concrete negative surface treatment agent and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the grafted modified starch ether is prepared by Preparation Example 6.

[0109] Example 8

[0110] A concrete negative surface treatment agent and a preparation method thereof. The specific implementation manner is the same as that of Example 1, except that the grafted modified starch ether is prepared by Preparation Example 7.

[0111] Comparative Example 1

[0112] A concrete negative surface treatment agent and a preparation method thereof, wherein the specific implementation manner is the same as that of Example 1, except that an equal mass portion of starch is used to replace the grafted modified starch ether.

[0113] Performance Test:

[0114] (1) Low temperature resistance test: A 1.5 mm thick negative surface treatment agent dry coating sample was placed in a -20°C freezer for 10 hours, and then subjected to a low temperature flexibility test according to GB / T1731-93.

[0115] (2) Adhesion test: Peel adhesion test was performed on steel plate according to JG / T375-2012;

[0116] (3) Concrete failure time: Place each concrete sample sprayed with the surface treatment agent outdoors at normal temperature and pressure to test the final setting time of the concrete;

[0117] (4) Stability test: Spray a 10 cm × 5 cm rectangular negative surface treatment agent onto the inner surface of the mold, dry at room temperature for 3 h, and then pour concrete into the mold. After vibration, the concrete is naturally cured and solidified. After molding, the concrete surface is demolded and rinsed to obtain image concrete. The change in the width of the rectangle is observed to determine whether it is vibration-resistant and stable. The concrete formula is shown in Table 1.

[0118] Table 1

[0119] Portland cement / kg Water / kg River sand / kg Crushed stone / kg 302 116 616 1134

[0120] The negative surface treatment agents for concrete of each embodiment and comparative example were tested according to the above method. The results are shown in Table 2.

[0121] Table 2

[0122]

[0123] According to the data in Table 1, it can be seen that the negative surface treatment agent for concrete prepared by using Examples 1 to 3 still has good flexibility and good adhesion at low temperatures, and has stable anti-vibration performance during use. After spraying the negative surface treatment agent for concrete, it can have the effect of making concrete fail for a long time; Example 4 uses an equal molar amount of di-n-hexylamine instead of di-n-propylamine, resulting in an increase in the steric hindrance of the tertiary amine, which hinders the grafted modified starch ether from forming a coordination bond with the mold, thereby reducing the peeling and bonding of the negative surface treatment agent; Example 5 uses an equal molar amount of heptaethylene glycol monomethyl ether instead of pentaethylene glycol, resulting in a decrease in the anti-sagging stability of the negative surface treatment agent, but an increase in low-temperature flexibility; Example 6 changes the molar ratio of cyanuric chloride to di-n-propylamine, so that the two active chlorines in cyanuric chloride react with di-n-propylamine, resulting in the branched structure of the grafted modified starch ether not having an ether bond. structure, thereby reducing the low temperature resistance of the negative surface treatment agent, but enhancing the adhesion ability; in Example 7, due to the change in the molar ratio of compound X to pentaethylene glycol, the starch cannot undergo Williamson reaction, resulting in a decrease in the low temperature resistance, adhesion ability and anti-sagging stability of the negative surface treatment agent, but compared with Comparative Example 1, although the Williamson reaction cannot occur, the compound still exists in the system, so the performance is slightly improved compared with the comparative example; in Example 8, due to the use of equimolar triethylene glycol monoethyl ether instead of pentaethylene glycol, the starch ether has a strong hydrophobicity, which reduces the wrapping ability of the styrene-acrylic emulsion, thereby reducing the stability of the surface treatment agent; in Comparative Example 1, due to the use of equal mass parts of starch instead of grafted modified starch ether, the low temperature resistance, adhesion ability and anti-sagging stability of the negative surface treatment agent are all reduced.

[0124] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A negative surface treatment agent for concrete, characterized in that: The invention comprises the following components in parts by weight: 450-550 parts of filler, 450-550 parts of water, 15-25 parts of grafted modified starch ether, 0.3-40 parts of hydration inhibitor, 98-102 parts of styrene acrylic emulsion, 1-6 parts of inorganic pigment, 0.5-0.7 parts of rust inhibitor, 0.1-0.7 parts of defoamer, 0.3-0.8 parts of drying agent and 0.1-0.3 parts of preservative.

2. A negative surface treatment agent for concrete according to claim 1, characterized in that: The filler is any one of heavy calcium powder, mica powder and talcum powder.

3. A concrete negative surface treatment agent according to claim 1, characterized in that: The grafted modified starch ether is composed of starch and a compound shown in formula I It is prepared by Williamson reaction, wherein R1 and R2 are independently C1-C3 alkyl groups, R3 is H, OH or CH3, and n is an integer of 1-4.

4. A negative surface treatment agent for concrete according to claim 3, characterized in that: When the R3 is H or CH3, n=an integer of 1 to 2; when the R3 is OH, n=an integer of 1 to 4.

5. A concrete negative surface treatment agent according to claim 4, characterized in that: The preparation method of the grafted modified starch ether specifically comprises the following steps: A1. Mix cyanuric chloride with deionized water, and then add the compound shown in formula II Adjust the system pH to 4-5, stir at room temperature for 22-24 hours, and obtain compound X by column chromatography after the reaction is completed; A2, the compound shown in formula III Mix with solvent, add sodium hydroxide, heat to 60-70°C and stir for 25-35 minutes, then add compound X in step A1, heat to 100-110°C and stir for 8-9 hours. After the reaction, adjust the pH of the system to neutral with dilute hydrochloric acid solution in an ice water bath, filter, concentrate and dry to obtain the compound shown in formula I A3. Mix starch and dimethyl sulfoxide and stir, add sodium hydroxide, heat to 70-80°C and stir for 30-40 min, then add the compound of formula I in step A2, heat to 100-110°C and stir for 11-13 h. After the reaction, adjust the pH of the system to neutral in an ice-water bath, filter, concentrate and dry to obtain grafted modified starch ether.

6. A concrete negative surface treatment agent according to claim 5, characterized in that: In step A1, the molar ratio of cyanuric chloride to the compound represented by formula II is 1:(0.2-0.3).

7. A concrete negative surface treatment agent according to claim 5, characterized in that: In step A2, the molar ratio of the compound X to the compound represented by formula III is 1:(0.9-1).

8. A negative surface treatment agent for concrete according to claim 1, characterized in that: The preparation method of the hydration inhibitor comprises the following steps: (1) Add formaldehyde solution dropwise to 8-hydroxyquinoline, then add concentrated hydrochloric acid and stir to dissolve, continue to introduce hydrogen chloride gas into the system until no more precipitation is produced to stop the reaction, filter, rinse with ether, and dry to obtain compound A; (2) Under an inert protective gas atmosphere, compound A in step (1), 1,2-di(2-chloroethoxy)ethane, potassium iodide and an acid binding agent are added to a solvent, the temperature is raised to 110-120° C. and stirred at a constant temperature for 46-50 hours. After the reaction is completed, the mixture is concentrated under reduced pressure, extracted, and the organic phases are combined and dried under reduced pressure and subjected to column chromatography to obtain a compound represented by formula IV (3) Mix the compound represented by formula IV in step (2) with N,N-dimethylaminomethanediphosphonic acid, add the solvent, heat to 100-120° C. and stir for 2-4 hours. After the reaction is completed, cool to room temperature, filter, wash with ethyl acetate, and concentrate and dry under reduced pressure to obtain a hydration inhibitor.

9. A method for preparing the negative surface treatment agent for concrete according to any one of claims 1 to 8, comprising the following steps: S1. Mix half of the water with the hydration inhibitor, inorganic pigment and grafted modified starch ether and stir for 30 to 40 minutes to obtain material A; S2, take the other half of the water and mix it with the filler, stirring and mixing for 20 to 30 minutes to obtain material B; S3. Add material B in step S2 to material A in step S1, control the rotation speed to 300-500 r / min, add defoamer and continue stirring until no bubbles are generated, then add styrene acrylic emulsion, rust inhibitor, drying agent and preservative, stir for 1-1.5 hours, and obtain the concrete negative surface treatment agent.

10. Use of the negative surface treatment agent for concrete according to any one of claims 1 to 8 in preparing image concrete, characterized in that: The method comprises the following steps: spraying a negative surface treatment agent onto the inner surface of a mold according to a pre-obtained pattern, drying at room temperature for 1 to 5 hours, pouring concrete into the mold, naturally curing the concrete after vibration to solidify and form, demolding and washing the concrete surface after forming to obtain image concrete.

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