Water-resistant putty powder and preparation method thereof

Abstract

The invention relates to the technical field of building materials, and discloses water-resistant putty powder and a preparation method thereof.The preparation method specifically comprises the following steps that stone powder, carboxymethyl cellulose, white cement, light calcium carbonate, etherified starch, silane modified chitosan and epoxy nano-silica are added into a stirrer to be stirred and mixed to be uniform, and the water-resistant putty powder is obtained. In the stirring process, hydroxyl groups in the silane modified chitosan and epoxy groups in the epoxy nano silicon dioxide are subjected to a ring-opening reaction, and a cross-linked network is generated between the hydroxyl groups and the epoxy groups, so that the silane modified chitosan and the epoxy nano silicon dioxide are connected more tightly, and the water-resistant effect of the putty powder is improved. Meanwhile, good mildew-proof, antibacterial and flame-retardant effects are also achieved.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a water-resistant putty powder and a preparation method thereof. Background Art

[0002] Putty powder is one of the commonly used materials in building decoration, and its performance directly affects the overall quality and safety of the building. However, during long-term use, it will come into contact with water vapor, bacteria and other substances in the air, causing peeling on the surface. Therefore, how to avoid this phenomenon is the key to solving the problem. For example, patent CN104945999A discloses a bactericidal and mildew-proof water-based putty powder and a preparation method thereof. The putty powder of the invention has good bactericidal and mildew-proof effects and air purification, but its water resistance and flame retardant effects are not improved. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a water-resistant putty powder and a preparation method thereof, which has good water-resistant, mildew-proof, antibacterial and flame-retardant effects.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a water-resistant putty powder, comprising the following components by weight: 100-150 parts by weight of stone powder, 4-6 parts by weight of carboxymethyl cellulose, 18-25 parts by weight of white cement, 2-3 parts by weight of light calcium carbonate, 10-12 parts by weight of etherified starch, 0.8-1.1 parts by weight of silane-modified chitosan, and 0.1-0.2 parts by weight of epoxy nano-silica.

[0005] Furthermore, the preparation method of the silane-modified chitosan is:

[0006] (1) Under a nitrogen atmosphere, chitosan is added to a reactor, methanesulfonic acid is added thereto to completely swell it, and then phosphorus pentoxide is added thereto, and mechanical stirring is carried out in an ice water bath for 3-4 hours, and the temperature is maintained at 0-5° C. After the reaction is completed, the product is precipitated with ether, and then filtered, washed, and dried to obtain phosphorylated chitosan;

[0007] (2) under nitrogen atmosphere, adding phosphorylated chitosan into a reactor, continuing to add toluene for swelling, and then adding thionyl chloride and ethanol, reacting at 40-42° C. for 3.8-4.1 h, washing, filtering and drying after completion, to obtain chlorinated phosphate chitosan;

[0008] (3) adding 2,2-bis(bromomethyl)-1,3-propylene glycol and cardanol to an acetone solvent, stirring evenly, and then continuing to add 2-3 mL of a 3-5 mol / L sodium hydroxide aqueous solution, reacting at 60-75° C. for 4-7 hours. After the reaction is completed, neutralizing with dilute hydrochloric acid, concentrating, filtering, washing and drying to obtain modified cardanol;

[0009] (4) adding the double-terminal epoxy silicone oil and modified cardanol to a reactor containing N,N-dimethylformamide, stirring and mixing, and continuously adding boron trifluoride ether catalyst thereto, reacting at 80-90° C. for 6-12 h, filtering after completion, washing with deionized water and ethanol in turn, and drying to obtain cardanol-modified silane;

[0010] (5) Adding cardanol-modified silane and acyl chloride phosphate chitosan to N,N-dimethylformamide solvent, stirring and mixing, and continuously adding triethylamine catalyst thereto, reacting at 76-95° C. for 5-7 h, and then distilling under reduced pressure and washing to obtain silane-modified chitosan.

[0011] In the above reaction process, chitosan is first phosphorylated with phosphorus pentoxide, then chlorinated with thionyl chloride, and then esterified with the hydroxyl groups in the cardanol-modified silane to obtain silane-modified chitosan; the preparation principle of cardanol-modified silane: the bromine in 2,2-bis(bromomethyl)-1,3-propanediol and the phenolic hydroxyl groups in the cardanol are substituted to introduce hydroxyl groups, and then the ring-opening reaction is carried out with the epoxy groups in the double-ended epoxy silicone oil to introduce new hydroxyl groups to obtain cardanol-modified silane.

[0012] Furthermore, the usage ratio of chitosan, methanesulfonic acid and phosphorus pentoxide in (1) is 1.8-2 g: 12-14 mL: 2-2.3 g.

[0013] Furthermore, in the method (2), the ratio of phosphorylated chitosan, toluene, thionyl chloride and ethanol is 2-2.1 g: 5-6 mL: 1-1.2 mL: 1.9-2.2 mL.

[0014] Furthermore, the mass ratio of 2,2-bis(bromomethyl)-1,3-propanediol to cardanol in (3) is 5-8g:7-12g.

[0015] Furthermore, the mass ratio of the double-ended epoxy silicone oil, modified cardanol, and boron trifluoride ether catalyst in (4) is 2.3-2.6 g: 3.5-4.1 g: 0.01-0.02 g.

[0016] Furthermore, the mass ratio of the cardanol-modified silane, the acyl chloride phosphate chitosan, and the triethylamine catalyst in (5) is 2.1-2.7 g: 1.5-1.7 g: 0.021-0.023 g.

[0017] Furthermore, the preparation method of the water-resistant putty powder is: adding stone powder, carboxymethyl cellulose, white cement, light calcium carbonate, etherified starch, silane-modified chitosan, and epoxy nano-silica into a stirrer, stirring for 15-20 minutes, and mixing evenly to obtain the water-resistant putty powder.

[0018] Furthermore, the viscosity of the carboxymethyl cellulose is 500, and the light calcium carbonate is 1250 mesh.

[0019] Beneficial effects:

[0020] The invention prepares water-resistant putty powder by adding stone powder, carboxymethyl cellulose, white cement, light calcium carbonate, etherified starch, silane-modified chitosan and epoxy nano-silicon dioxide into a stirrer, stirring and mixing evenly.

[0021] During the stirring process, the hydroxyl groups in the silane-modified chitosan will undergo a ring-opening reaction with the epoxy groups in the epoxy nano-silica, while reducing the agglomeration of nano-silica, forming a cross-linked network between each other, making them more closely connected, and improving the water resistance of the putty powder. The long chain in the cardanol in the silane-modified chitosan has a good hydrophobic effect, which can improve the water resistance of the putty powder. After the cardanol-modified silane and the acyl chloride phosphate chitosan react, the silane-modified chitosan is generated, and the substitution degree of cardanol is also increased, further improving the water resistance of the putty powder. The chitosan and epoxy nano-silica in the silane-modified chitosan themselves have good flame retardant, mildew-proof and antibacterial effects. The phosphorus element in the silane-modified chitosan can generate polyphosphoric acid and metaphosphoric acid with strong dehydration when burning. Since polyphosphoric acid and metaphosphoric acid are not easy to volatilize, they can form a dense protective layer on the surface of the putty powder, thereby playing a flame retardant effect. 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] Add 12.8g of octamethylcyclotetrasiloxane and 1g of 1,3-diglycidyloxypropyl-1,1,3,3-tetramethyldisiloxane to the reaction kettle, add 11mg of catalyst tetramethylammonium hydroxide in a nitrogen atmosphere, raise the temperature to 110°C, react for 4h, then raise the temperature to 140°C, react for 1h, cool and discharge to obtain double-ended epoxy silicone oil.

[0024] Preparation of epoxy nano-silica: Referring to the literature "Nano-silica modified with silane coupling agent KH-560", a certain amount of nano-silica was weighed and added to 20 mL of toluene. Ultrasonic dispersion was performed for 30 min at room temperature using a KQ-300E ultrasonic cleaner (300 W) to obtain a uniform suspension. Silane coupling agent KH-560 was then added and ultrasonic dispersion was continued for 3-4 min. The suspension was transferred to a 100 mL four-necked flask equipped with a reflux condenser and a power-enhanced electric stirrer and stirred in an oil bath at a set temperature for reaction. The slurry after the reaction was centrifuged at room temperature at a speed of 12000 r / min using a CT15RT desktop high-speed refrigerated centrifuge to obtain epoxy nano-silica.

[0025] Example 1

[0026] (1) Under a nitrogen atmosphere, 1.8 g of chitosan was added to a reactor, and then 12 mL of methane sulfonic acid was added thereto to completely swell the chitosan. Then 2 g of phosphorus pentoxide was added, and the mixture was mechanically stirred in an ice water bath for 3 h. The temperature was maintained at 0° C. After the reaction was completed, the product was precipitated with ether, and then filtered, washed, and dried to obtain phosphorylated chitosan.

[0027] (2) Under nitrogen atmosphere, 2 g of phosphorylated chitosan was added into the reactor, and 5 mL of toluene was added for swelling, and then 1 mL of thionyl chloride and 1.9 mL of ethanol were added, and the reaction was carried out at 40° C. for 3.8 h. After the reaction was completed, the reaction was washed, filtered and dried to obtain chlorinated phosphate chitosan;

[0028] (3) Add 5 g of 2,2-bis(bromomethyl)-1,3-propylene glycol and 7 g of cardanol to 40 mL of acetone solvent, stir evenly, then continue to add 2 mL of 3 mol / L sodium hydroxide aqueous solution, react at 60° C. for 4 h, and after the reaction is completed, neutralize with dilute hydrochloric acid, concentrate, filter, wash and dry to obtain modified cardanol;

[0029] (4) Add 2.3 g of double-ended epoxy silicone oil and 3.5 g of modified cardanol to a reactor containing 30 mL of N,N-dimethylformamide, stir and mix, continue to add 0.01 g of boron trifluoride ether catalyst, react at 80 ° C for 6 h, filter after completion, wash with deionized water and ethanol in turn, and dry to obtain cardanol-modified silane;

[0030] (5) Add 2.1 g of cardanol-modified silane and 1.5 g of acyl chloride phosphate chitosan to 25 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.021 g of triethylamine catalyst, react at 76 ° C for 5 h, and then perform vacuum distillation and washing to obtain silane-modified chitosan;

[0031] (6) Add 100 g of stone powder, 4 g of carboxymethyl cellulose, 18 g of white cement, 2 g of light calcium carbonate, 10 g of etherified starch, 0.8 g of silane-modified chitosan, and 0.1 g of epoxy nano-silica into a stirrer and stir for 15 min. After mixing evenly, a water-resistant putty powder is obtained.

[0032] Example 2

[0033] (1) Under a nitrogen atmosphere, 2 g of chitosan was added to a reactor, and then 14 mL of methane sulfonic acid was added thereto to completely swell it, and then 2.3 g of phosphorus pentoxide was added, and mechanical stirring was carried out in an ice water bath for 4 h, and the temperature was maintained at 5° C. After the reaction was completed, the product was precipitated with ether, and then filtered, washed, and dried to obtain phosphorylated chitosan;

[0034] (2) Under nitrogen atmosphere, 2.1 g of phosphorylated chitosan was added into the reactor, and 6 mL of toluene was added for swelling, and then 1.2 mL of thionyl chloride and 2.2 mL of ethanol were added, and the reaction was carried out at 42° C. for 4.1 h. After the reaction, the reaction was washed, filtered and dried to obtain chlorinated phosphate chitosan;

[0035] (3) Add 8 g of 2,2-bis(bromomethyl)-1,3-propylene glycol and 12 g of cardanol to 50 mL of acetone solvent, stir evenly, then continue to add 2 mL of 5 mol / L sodium hydroxide aqueous solution, react at 75 ° C for 7 h, after the reaction is completed, neutralize with dilute hydrochloric acid, concentrate, filter, wash and dry to obtain modified cardanol;

[0036] (4) Add 2.6 g of double-ended epoxy silicone oil and 4.1 g of modified cardanol to a reactor containing 40 mL of N,N-dimethylformamide, stir and mix, continue to add 0.02 g of boron trifluoride ether catalyst, react at 90° C. for 12 h, filter after completion, wash with deionized water and ethanol in turn, and dry to obtain cardanol-modified silane;

[0037] (5) Add 2.7 g of cardanol-modified silane and 1.7 g of acyl chloride phosphate chitosan to 40 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.023 g of triethylamine catalyst, react at 95 ° C for 7 h, and then perform vacuum distillation and washing to obtain silane-modified chitosan;

[0038] (6) Add 150 g of stone powder, 6 g of carboxymethyl cellulose, 25 g of white cement, 3 g of light calcium carbonate, 12 g of etherified starch, 1.1 g of silane-modified chitosan, and 0.2 g of epoxy nano-silica into a stirrer and stir for 20 min. After mixing evenly, a water-resistant putty powder is obtained.

[0039] Example 3

[0040] (1) Under a nitrogen atmosphere, 1.9 g of chitosan was added to a reactor, and then 13 mL of methanesulfonic acid was added thereto to completely swell the chitosan. Then, 2.2 g of phosphorus pentoxide was added thereto, and the mixture was mechanically stirred in an ice-water bath for 3 h. The temperature was maintained at 4° C. After the reaction was completed, the product was precipitated with ether, and then filtered, washed, and dried to obtain phosphorylated chitosan.

[0041] (2) Under nitrogen atmosphere, 2 g of phosphorylated chitosan was added into the reactor, and 5 mL of toluene was added for swelling, and then 1.1 mL of thionyl chloride and 2.1 mL of ethanol were added, and the reaction was carried out at 41° C. for 4 h. After the reaction, the reaction was washed, filtered and dried to obtain chlorinated phosphate chitosan;

[0042] (3) Add 6 g of 2,2-di(bromomethyl)-1,3-propylene glycol and 9 g of cardanol to 45 mL of acetone solvent, stir evenly, then continue to add 2 mL of 4 mol / L sodium hydroxide aqueous solution, react at 62 ° C for 6 h, after the reaction is completed, neutralize with dilute hydrochloric acid, concentrate, filter, wash and dry to obtain modified cardanol;

[0043] (4) Add 2.5 g of double-ended epoxy silicone oil and 3.8 g of modified cardanol to a reactor containing 35 mL of N,N-dimethylformamide, stir and mix, continue to add 0.015 g of boron trifluoride ether catalyst, react at 85° C. for 10 h, filter after completion, wash with deionized water and ethanol in turn, and dry to obtain cardanol-modified silane;

[0044] (5) Add 2.4 g of cardanol-modified silane and 1.6 g of acyl chloride phosphate chitosan to 30 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.022 g of triethylamine catalyst, react at 85 ° C for 6 h, and then perform vacuum distillation and washing to obtain silane-modified chitosan;

[0045] (6) Add 125 g of stone powder, 5 g of carboxymethyl cellulose, 22 g of white cement, 2 g of light calcium carbonate, 11 g of etherified starch, 0.9 g of silane-modified chitosan, and 0.15 g of epoxy nano-silica into a stirrer and stir for 18 min. After mixing evenly, a water-resistant putty powder is obtained.

[0046] Example 4

[0047] (1) Under a nitrogen atmosphere, 1.8 g of chitosan was added to a reactor, and then 12 mL of methane sulfonic acid was added thereto to completely swell the chitosan. Then 2 g of phosphorus pentoxide was added, and the mixture was mechanically stirred in an ice water bath for 3 h. The temperature was maintained at 0° C. After the reaction was completed, the product was precipitated with ether, and then filtered, washed, and dried to obtain phosphorylated chitosan.

[0048] (2) Under nitrogen atmosphere, 2 g of phosphorylated chitosan was added into the reactor, and 5 mL of toluene was added for swelling, and then 1 mL of thionyl chloride and 1.9 mL of ethanol were added, and the reaction was carried out at 40° C. for 3.8 h. After the reaction was completed, the reaction was washed, filtered and dried to obtain chlorinated phosphate chitosan;

[0049] (3) Add 8 g of 2,2-bis(bromomethyl)-1,3-propylene glycol and 12 g of cardanol to 50 mL of acetone solvent, stir evenly, then continue to add 3 mL of 5 mol / L sodium hydroxide aqueous solution, react at 75 ° C. for 7 h. After the reaction is completed, neutralize with dilute hydrochloric acid, concentrate, filter, wash and dry to obtain modified cardanol;

[0050] (4) Add 2.6 g of double-ended epoxy silicone oil and 4.1 g of modified cardanol to a reactor containing 40 mL of N,N-dimethylformamide, stir and mix, continue to add 0.02 g of boron trifluoride ether catalyst, react at 90° C. for 12 h, filter after completion, wash with deionized water and ethanol in turn, and dry to obtain cardanol-modified silane;

[0051] (5) Add 2.4 g of cardanol-modified silane and 1.6 g of acyl chloride phosphate chitosan to 30 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.022 g of triethylamine catalyst, react at 85 ° C for 6 h, and then perform vacuum distillation and washing to obtain silane-modified chitosan;

[0052] (6) Add 125 g of stone powder, 5 g of carboxymethyl cellulose, 22 g of white cement, 2 g of light calcium carbonate, 11 g of etherified starch, 0.9 g of silane-modified chitosan, and 0.15 g of epoxy nano-silica into a stirrer and stir for 18 min. After mixing evenly, a water-resistant putty powder is obtained.

[0053] Example 5

[0054] (1) Under a nitrogen atmosphere, 2 g of chitosan was added to a reactor, and then 14 mL of methane sulfonic acid was added thereto to completely swell it, and then 2.3 g of phosphorus pentoxide was added, and mechanical stirring was carried out in an ice water bath for 4 h, and the temperature was maintained at 5° C. After the reaction was completed, the product was precipitated with ether, and then filtered, washed, and dried to obtain phosphorylated chitosan;

[0055] (2) Under nitrogen atmosphere, 2.1 g of phosphorylated chitosan was added into the reactor, and 6 mL of toluene was added for swelling, and then 1.2 mL of thionyl chloride and 2.2 mL of ethanol were added, and the reaction was carried out at 42° C. for 4.1 h. After the reaction, the reaction was washed, filtered and dried to obtain chlorinated phosphate chitosan;

[0056] (3) Add 6 g of 2,2-di(bromomethyl)-1,3-propylene glycol and 9 g of cardanol to 45 mL of acetone solvent, stir evenly, then continue to add 2 mL of 4 mol / L sodium hydroxide aqueous solution, react at 62 ° C for 6 h, after the reaction is completed, neutralize with dilute hydrochloric acid, concentrate, filter, wash and dry to obtain modified cardanol;

[0057] (4) Add 2.5 g of double-ended epoxy silicone oil and 3.8 g of modified cardanol to a reactor containing 35 mL of N,N-dimethylformamide, stir and mix, continue to add 0.015 g of boron trifluoride ether catalyst, react at 85° C. for 10 h, filter after completion, wash with deionized water and ethanol in turn, and dry to obtain cardanol-modified silane;

[0058] (5) Add 2.1 g of cardanol-modified silane and 1.5 g of acyl chloride phosphate chitosan to 25 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.021 g of triethylamine catalyst, react at 76 ° C for 5 h, and then perform vacuum distillation and washing to obtain silane-modified chitosan;

[0059] (6) Add 100 g of stone powder, 4 g of carboxymethyl cellulose, 18 g of white cement, 2 g of light calcium carbonate, 10 g of etherified starch, 0.8 g of silane-modified chitosan, and 0.1 g of epoxy nano-silica into a stirrer and stir for 15 min. After mixing evenly, a water-resistant putty powder is obtained.

[0060] Comparative Example 1

[0061] Compared with Example 5, this comparative example is different in that nano-silicon dioxide is used instead of epoxy nano-silicon dioxide.

[0062] Comparative Example 2

[0063] Compared with Example 5, this comparative example is different in that chitosan is used instead of silane-modified chitosan.

[0064] Comparative Example 3

[0065] Compared with Example 5, the difference between this comparative example and Example 5 is that chitosan is used instead of silane-modified chitosan, and nano-silica is used instead of epoxy nano-silica.

[0066] The putty powders prepared in Examples 1-5 and Comparative Examples 1-3 are now tested.

[0067] 1. Anti-mildew performance test: The test method refers to GB / T 1741-2007 "Determination of mildew resistance of paint film" standard. The higher the rating, the worse the anti-mildew effect, and the lower the rating, the better the anti-mildew effect. The antibacterial performance test was conducted on Escherichia coli. Each group was tested three times and the average value was taken.

[0068] Table 1: Antifungal and antibacterial tests.

[0069] project Anti-fungal Antibacterial rate (%) Example 1 Level 0 99.5 Example 2 Level 0 99.8 Example 3 Level 0 99.6 Example 4 Level 0 99.7 Example 5 Level 0 99.6 Comparative Example 1 Level 1 85.2 Comparative Example 2 Level 1 86.1 Comparative Example 3 Level 1 80.5

[0070] As can be seen from Table 1, Examples 1-5 of the present invention have better antifungal properties than Comparative Examples 1-3.

[0071] 2. Water resistance test: The samples of Examples 1-5 and Comparative Examples 1-3 were scraped on the same interior wall respectively, with a putty thickness of about 2 mm. After the putty dried, water was poured on the wall, and the wall was kept moist for 100 hours. The condition of the wall putty was observed.

[0072] Table 2: Water resistance test.

[0073] project Water resistance Example 1 No peeling, no powdering Example 2 No peeling, no powdering Example 3 No peeling, no powdering Example 4 No peeling, no powdering Example 5 No peeling, no powdering Comparative Example 1 No peeling, no powdering Comparative Example 2 No peeling, no powdering Comparative Example 3 Slightly peeling, no powder falling off

[0074] It can be seen from Table 2 that Examples 1-5 of the present invention have better water resistance than Comparative Examples 1-3.

[0075] 3. Flame retardancy test: Oxygen index is tested according to GB / T2406.1-2008 standard.

[0076] Table 3: Flame retardancy test.

[0077]

[0078]

[0079] It can be seen from Table 3 that Examples 1-5 of the present invention have better flame retardancy than Comparative Examples 1-3.

[0080] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A water-resistant putty powder, characterized in that: It consists of the following components by weight: 100-150 parts by weight of stone powder, 4-6 parts by weight of carboxymethyl cellulose, 18-25 parts by weight of white cement, 2-3 parts by weight of light calcium carbonate, 10-12 parts by weight of etherified starch, 0.8-1.1 parts by weight of silane-modified chitosan, and 0.1-0.2 parts by weight of epoxy nano-silica.

2. The water-resistant putty powder according to claim 1, characterized in that: The preparation method of the silane-modified chitosan is: (1) In an inert gas atmosphere, chitosan is added to a reactor, methanesulfonic acid is added thereto to completely swell it, and then phosphorus pentoxide is added thereto, and mechanical stirring is performed in an ice water bath for 3-4 hours, and the temperature is maintained at 0-5° C. After the reaction is completed, the product is precipitated with ether, and then filtered, washed, and dried to obtain phosphorylated chitosan; (2) under an inert gas atmosphere, adding the phosphorylated chitosan into a reactor, continuing to add toluene for swelling, and then adding thionyl chloride and ethanol, reacting at 40-42° C. for 3.8-4.1 hours, washing after the reaction, filtering and drying to obtain chlorinated phosphate chitosan; (3) adding 2,2-bis(bromomethyl)-1,3-propylene glycol and cardanol to the solvent, stirring evenly, and then continuing to add sodium hydroxide aqueous solution, reacting at 60-75° C. for 4-7 hours. After the reaction is completed, neutralizing with dilute hydrochloric acid, concentrating, filtering, washing and drying to obtain modified cardanol; (4) adding the double-terminal epoxy silicone oil and modified cardanol to a reactor containing N,N-dimethylformamide, stirring and mixing, and continuously adding boron trifluoride ether catalyst thereto, reacting at 80-90° C. for 6-12 h, filtering after completion, washing with deionized water and ethanol in turn, and drying to obtain cardanol-modified silane; (5) Adding cardanol-modified silane and acyl chloride phosphate chitosan to N,N-dimethylformamide solvent, stirring and mixing, and continuously adding triethylamine catalyst thereto, reacting at 76-95° C. for 5-7 h, and then distilling under reduced pressure and washing to obtain silane-modified chitosan.

3. The water-resistant putty powder according to claim 2, characterized in that: The dosage ratio of chitosan, methanesulfonic acid and phosphorus pentoxide in (1) is 1.8-2g:12-14mL:2-2.3g.

4. The water-resistant putty powder according to claim 2, characterized in that: The usage ratio of phosphorylated chitosan, toluene, thionyl chloride and ethanol in (2) is 2-2.1 g: 5-6 mL: 1-1.2 mL: 1.9-2.2 mL.

5. The water-resistant putty powder according to claim 2, characterized in that: The mass ratio of 2,2-bis(bromomethyl)-1,3-propanediol to cardanol in (3) is 5-8g:7-12g.

6. The water-resistant putty powder according to claim 2, characterized in that: The mass ratio of the double-ended epoxy silicone oil, modified cardanol, and boron trifluoride ether catalyst in (4) is 2.3-2.6g: 3.5-4.1g: 0.01-0.02g.

7. The water-resistant putty powder according to claim 2, characterized in that: The mass ratio of cardanol-modified silane, acyl chloride phosphate chitosan and triethylamine catalyst in (5) is 2.1-2.7g:1.5-1.7g:0.021-0.023g.

8. A method for preparing a water-resistant putty powder according to any one of claims 1 to 7, characterized in that: The preparation method of the water-resistant putty powder is as follows: stone powder, carboxymethyl cellulose, white cement, light calcium carbonate, etherified starch, silane-modified chitosan and epoxy nano-silica are added into a stirrer, stirred for 15-20 minutes, and mixed evenly to obtain the water-resistant putty powder.

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