Rigid surface treatment agent and preparation method thereof, and associated coatings, coatings and protective materials

Abstract

The invention belongs to the field of coatings, and particularly relates to a rigid surface treating agent and a preparation method thereof as well as a related coating, coating and protective material.The preparation method of the rigid surface treating agent comprises the following steps: polymerizing amino siloxane to obtain polyamino siloxane sol; carrying out first-stage grafting reaction on the modified polysiloxane and the modified polysiloxane shown in the formula 1 to obtain grafted modified polysiloxane shown in the formula 1; and carrying out a second-stage grafting reaction on the modified polysiloxane, a formula (2) and an isocyanate crosslinking agent, and modifying the formula (2) on the modified polysiloxane to prepare the rigid surface treating agent. The preparation method comprises the following steps: modifying a formula 1 in a polyaminosiloxane sol in advance, and then modifying a formula 2 to prepare the network-like polyaminosiloxane surface treating agent with excellent rigidity, so that the adhesive force and the mechanical strength of a coating are greatly enhanced, the wear resistance is effectively improved, and the light transmittance is excellent.

Description

Technical Field

[0001] The invention belongs to the field of surface treatment agents, and in particular relates to the field of rigid surface treatment agents. Background Art

[0002] Fluorosilicone coatings are widely used in specialized coating applications such as aerospace, electronics, textiles, and machinery due to their excellent heat and weather resistance, low friction coefficient, and excellent hydrophobic and oleophobic self-cleaning properties. However, glass coatings used in high-speed vehicles like trains and airplanes require high hardness, high light transmittance, a low friction coefficient, and hydrophobic and oleophobic antifouling properties to reduce frictional resistance, prevent visual interference, and ensure safe operation.

[0003] Traditional fluorosilicone coatings and paints primarily include fluorosilicone water-based paints and silicone-modified polyester resins. For example, fluorosilicone water-based paints primarily use aqueous dispersions of silicone-containing polymers and fluoropolymers as film-forming materials and are widely used in exterior wall coatings, particularly latex paints. Silicone-modified polyester resins are polyesters derived from the condensation of diols (or polyols) and dibasic acids (or polyacids or anhydrides), which are then modified with silicone to form thermosetting resins.

[0004] For example, patent document CN105350317A discloses an environmentally friendly super-hydrophobic and oil-proof surface treatment agent for textiles, which is mainly composed of the following raw materials in parts by weight: 1 to 15 parts of a fluorine-containing compound, 1 to 5 parts of a silicon-containing compound, 1 to 15 parts of a fluorine-silicon copolymer, 0.5 to 5 parts of a silane coupling agent and 50 to 95 parts of a solvent. The reaction temperature is 5 to 45°C and the reaction time is 0.5 to 3 hours.

[0005] For example, patent document CN104530851A discloses a surface treatment agent, which is made of the following substances in percentage by weight: 5% to 50% film-forming substance, 5% to 15% nano-oxide, 0.5% to 20% additive, and 15% to 89.5% deionized water.

[0006] In summary, although some fluorosilicone coating solutions have been reported in the prior art and have achieved good results, it is still difficult for existing solutions to simultaneously achieve high hardness, high hydrophobicity and long-term wear resistance of the coating, and therefore it is difficult to meet the requirements for the use of protective coatings under extreme conditions. Summary of the Invention

[0007] In view of the defects of the prior art, the first purpose of the present invention is to provide a method for preparing a surface treatment agent with strong rigidity, aiming to prepare a surface treatment agent with excellent properties such as high transmittance, hydrophobicity and anti-fouling, high wear resistance, and high mechanical strength.

[0008] The second purpose of the present invention is to provide a rigid surface treatment agent obtained by the preparation method.

[0009] The third object of the present invention is to provide a coating material comprising the rigid surface treatment agent and its associated coating and protective material.

[0010] A method for preparing a rigid surface treatment agent, comprising the steps of:

[0011] Step 1:

[0012] The aminosiloxane is polymerized to obtain a polyaminosiloxane sol; and then the polyaminosiloxane sol is subjected to a first-stage grafting reaction with the polysiloxane of Formula 1 to obtain a grafted modified polysiloxane of Formula 1;

[0013] Formula 1;

[0014] In formula 1, m and n are integers between 0 and 30, and m and n are not 0 at the same time;

[0015] Step 2:

[0016] The modified polysiloxane, Formula 2, and an isocyanate crosslinking agent are subjected to a second-stage grafting reaction to modify Formula 2 on the modified polysiloxane to obtain the rigid surface treatment agent;

[0017] Formula 2;

[0018] In formula 2, R1 is H, C1~C 10 Alkyl, C3~C 10 a cycloalkyl or phenyl group;

[0019] R2 is a substituent having a carbon number of less than 10 and containing a substituent a, wherein the substituent a comprises at least one of a hydroxyl group, an amino group, a halogen group, and a mercapto group.

[0020] The present invention pre-modifies Formula 1 in a polyaminosiloxane sol and then modifies Formula 2 to prepare a network polyaminosiloxane surface treatment agent with excellent rigidity, which can greatly enhance the adhesion and mechanical strength of the coating and effectively improve the wear resistance and light transmittance.

[0021] In the present invention, the aminosilicone has the structural formula 3;

[0022] Formula 3;

[0023] wherein R3 is a C1~C8 alkylene group or -X1-NH-X2, wherein X1 and X2 are C1~C8 alkylene groups;

[0024] R4 is a C1~C8 alkyl group;

[0025] R5 is at least one of a hydrogen atom, a C1-C8 alkyl group, and a C1-C8 alkoxy group.

[0026] In the present invention, the solvent for the polymerization process of Formula 3 can be an alcohol-water solvent, wherein the alcohol can be a C1-C4 alcohol, further comprising methanol, ethanol, etc. The acid used in the polymerization process can be hydrochloric acid, sulfuric acid, etc. The temperature during the polymerization process can be above 50°C, for example, 50-80°C. The polymerization time can be 1-5 hours.

[0027] Furthermore, during the polymerization process, the amount of raw materials can be reasonably adjusted as needed. For example, the molar ratio of aminosiloxane (molar amount based on amino group), alcohol, acid, and water is 0.5-2:20-50:0.002-0.005:0.5-1.5; more preferably, it is 1-1.2:35-50:0.003-0.004:1-1.2.

[0028] In the present invention, Formula 1 is obtained by reacting Formula 4 and Formula 5;

[0029] Formula 4;

[0030] In formula 4, m and n are the same as those in formula 1;

[0031] Formula 5;

[0032] X is a halogen, for example, Cl.

[0033] In the present invention, m can be 4 to 12. n can be 2 to 12.

[0034] In the present invention, the molar ratio of the hydroxyl group in Formula 4 to the hydroxyl group in Formula 5 may be 1:0.8-1.2; further, it may be 1:1.1-1.2.

[0035] In the present invention, a catalyst may be added during the reaction of Formula 4 and Formula 5. The catalyst may be at least one of sodium hydroxide and potassium hydroxide. Furthermore, the amount of the catalyst used is 1.0 to 3.0 wt % of the weight of Formula 4, and further may be 1.1 to 2 wt %.

[0036] In the present invention, the molar ratio of the polyaminosiloxane sol (calculated based on the amino groups therein) to Formula 1 is 0.9-1.2:1; further, it can be 0.95-1.15:1.

[0037] The reaction is carried out under reflux under heating conditions at a temperature of 35-45°C and a reaction time of 3-5 hours.

[0038] In Formula 2, R1 is a C1-C8 alkyl group, and may further be a C2-C5 alkyl group. R2 is a group bearing the substituent a on a C1-C8 linear carbon chain, an oxygen-heterolinear carbon chain, or a five- or six-membered saturated carbon ring. Furthermore, the substituent a is a hydroxyl group. Studies have shown that the preferred functionalized Formula 2 can be combined with the process of the present invention to further enhance the wear resistance of the resulting treatment agent.

[0039] In the present invention, the isocyanate crosslinking agent can be at least one of hexamethylene diisocyanate (HDI), 2,2,4- and / or 2,4,4-trimethylhexamethylene diisocyanate, p- and m-tetramethylxylene diisocyanate, hydrogenated MDI (methylene bis(4-cyclohexyl diisocyanate)), methylene-4,4'-diphenyl diisocyanate, p-m-xylylene diisocyanate, 2,4- and / or 2,6-toluene diisocyanate (TDI) and its adducts, and isophorone diisocyanate (IPDI); more preferably, the polyisocyanate is isophorone diisocyanate or hexamethylene diisocyanate.

[0040] In the present invention, the molar ratio of Formula 2, the isocyanate crosslinking agent, and Formula 1 is 0.3-1.4:0.8-1.2:1; further, it can be 0.95-1.15:1-1.1:1.

[0041] In step 2 of the present invention, an organic Sn catalyst is further added, which can be at least one of dibutyltin diacetate, dibutyltin dilaurate, and di(dodecylthio)dibutyltin. The amount of the organic Sn catalyst is 2.0 to 4.0 wt% based on the weight of Formula 1.

[0042] In step 2 of the present invention, the solvent for the second grafting reaction can be at least one of acetone, ethyl acetate, ethyl butyrate, tetrahydrofuran, hydrofluoroether, and the like.

[0043] In the present invention, the atmosphere of the second grafting reaction can be at least one of nitrogen, argon and helium.

[0044] In the present invention, the temperature of the second grafting reaction can be 30-50° C., and the time can be 2-5 hours.

[0045] The present invention also includes a rigid surface treatment agent prepared by the preparation method.

[0046] The present invention also provides a coating, which comprises the rigid surface treatment agent prepared by the preparation method of the present invention and at least one of a diluent and an auxiliary agent.

[0047] In the present invention, except for the rigid surface treatment agent of the present invention, the other components of the coating may be well-known, and the contents of the components may be known.

[0048] For example, the coating contains a diluent, which may be a conventional fluorinated diluent, or may further be a hydrofluoroether, or may further be 3M 7200.

[0049] In the coating of the present invention, the solid content of the rigid surface treatment agent may be 5% to 50%, and more preferably 20% to 30%.

[0050] The present invention also provides a coating, which is obtained by coating and drying the coating of the present invention.

[0051] The present invention also provides a protective material, comprising a substrate to be protected and a coating composited on the surface thereof, wherein the coating is the coating of the present invention.

[0052] The substrate is a glass screen, a windshield, a lens, a plastic plate, etc.

[0053] Beneficial effects

[0054] 1) The present invention provides a method for preparing a rigid surface treatment agent, which pre-forms a polyaminosiloxane sol, then performs a first-stage grafting on it using Formula 1, and then performs a second-stage grafting on it using a functionalized Formula 2. This can achieve synergy, optimize the network structure and active group content of the treatment agent, effectively solve the phase separation caused by the nano-size effect of the components, and significantly enhance the adhesion and mechanical strength of the coating, effectively improve the wear resistance, and have excellent light transmittance.

[0055] 2) The method for preparing a surface treatment agent with strong rigidity provided by the present invention has the advantages of simple operation steps and mild reaction conditions, and provides a new idea for the preparation of a new type of highly stable and wear-resistant surface treatment agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is the SEM spectrum of the coating prepared in Example 1;

[0057] Figure 2 This is the SEM spectrum of the coating prepared in Comparative Example 4. DETAILED DESCRIPTION

[0058] The technical solution of the present invention will be further described below in conjunction with specific embodiments of the present invention. It should be noted that the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments; these embodiments are only for a better understanding of the present invention, and do not limit the scope of protection of the present invention.

[0059] Unless otherwise specified, all reagents and raw materials used in the present invention are commercially available products or products that can be prepared by known methods.

[0060] The room temperature in the examples of the present invention and the comparative examples is 25°C.

[0061] Example 1

[0062] This embodiment provides a surface treatment agent with strong rigidity, and the specific preparation method includes the following preparation steps:

[0063] 1) Weigh 3-aminopropyltrimethoxysilane and dissolve it in ethanol. Then add hydrochloric acid and deionized water (molar ratio of 1:36:0.0035:1.1, respectively). Mix well in a three-necked flask, heat to 60°C, and reflux for 2 hours to obtain a polyaminosiloxane sol.

[0064] 2) Formula 4 (m=12, n=12) and epichlorohydrin in a molar ratio of 1:1.2 were added to acetone, and sodium hydroxide (1.15 wt% of the weight of Formula 4) was added. The mixture was heated to 65°C and reacted for 3 hours to obtain a product having the structure of Formula 1 (wherein m and n are both 12).

[0065] 3) adding the product of formula 1 obtained in step (2) to the polyaminosiloxane sol obtained in step (1) (the molar ratio of amino groups in the polyaminosiloxane sol to formula 1 is 1:1), stirring at 40° C., heating under reflux for 4 h, performing a ring-opening reaction, and obtaining a grafted modified polysiloxane of formula 1 after purification;

[0066] 4) Weigh hexamethylene diisocyanate and formula 2A ( ) is added to the modified polysiloxane grafted with formula 1 obtained in step (3) (its molar amount is calculated based on the grafted formula 1) (the molar ratio is 1.1:1:1 respectively), the solvent is acetone, dibutyltin diacetate is added (its amount is 3 wt% of the weight of formula I in step 3), and the reaction is carried out at 45°C for 3h under a nitrogen atmosphere. After separation and purification, a composite sol is obtained;

[0067] The composite sol prepared above was compounded with hydrofluoroether 3M 7200, and the solid content was adjusted to 25% to obtain a surface treatment agent with strong rigidity.

[0068] Depend on Figure 1 It can be seen from the SEM spectrum that the coating surface formed by the above surface treatment agent is smooth and no crystals of formula 2A are present, which confirms the excellence of this technical solution.

[0069] Example 2

[0070] This embodiment provides a surface treatment agent with strong rigidity, and the specific preparation method includes the following preparation steps:

[0071] 1) Weigh N-[3-(trimethoxysilyl)propyl]ethylenediamine and dissolve it in ethanol. Then add hydrochloric acid and deionized water (molar ratio of 1:40:0.004:1.1, respectively). Mix well in a three-necked flask, heat to 65°C, and reflux for 2 hours to obtain a polyaminosiloxane sol.

[0072] 2) Formula 4 (m=12, n=12) and epichlorohydrin in a molar ratio of 1:1.15 were added to acetone, and sodium hydroxide (1.5 wt% of the weight of Formula 4) was added. The mixture was heated to 70°C and reacted for 3.5 hours to obtain a product having the structure of Formula 1 (wherein m and n are both 12).

[0073] 3) adding the product of formula 1 obtained in step (2) to the polyaminosiloxane sol obtained in step (1) (the molar ratio of amino groups in the polyaminosiloxane sol to formula 1 is 1.05:1), stirring at 43° C., heating under reflux for 4 h, performing a ring-opening reaction, and obtaining a grafted modified polysiloxane of formula 1 after purification;

[0074] 4) Weigh isophorone diisocyanate, formula 2B ( ) is added to the modified polysiloxane grafted with formula 1 obtained in step (3) (its molar amount is calculated based on the grafted formula 1) (the molar ratio is 1.02:0.6:1 respectively), the solvent is acetone, dibutyltin diacetate is added (its amount is 3 wt% of the weight of formula 1 in step 3), and the reaction is carried out at 40°C for 4h under a nitrogen atmosphere. After separation and purification, a composite sol is obtained;

[0075] The composite sol prepared above was compounded with hydrofluoroether 3M 7200, and the solid content was adjusted to 25% to obtain a surface treatment agent with strong rigidity.

[0076] Example 3

[0077] This embodiment provides a surface treatment agent with strong rigidity, and the specific preparation method includes the following preparation steps:

[0078] 1) Weigh 3-aminopropyltriethoxysilane and dissolve it in ethanol. Then add hydrochloric acid and deionized water (molar ratio of 1:50:0.0025:0.8, respectively). Mix well in a three-necked flask, heat to 70°C, and reflux for 1.5 hours to obtain a precursor sol.

[0079] 2) Compound 4 (m=4, n=2) and epichlorohydrin in a molar ratio of 1:1.1 were added to acetone, and sodium hydroxide (2 wt% of the weight of compound 4) was added. The mixture was heated to 65°C and reacted for 4 hours to obtain a product having the structure of Formula 1 (m=4, n=2).

[0080] 3) adding the product of formula 1 obtained in step (2) to the polyaminosiloxane sol obtained in step (1) (the molar ratio of amino groups in the polyaminosiloxane sol to formula 1 is 0.95:1), stirring at 45° C., heating under reflux for 4 h, performing a ring-opening reaction, and obtaining a grafted modified polysiloxane of formula 1 after purification;

[0081] 4) Weigh methylene-4,4'-diphenyl diisocyanate, formula 2C( ) is added to the modified polysiloxane grafted with formula 1 obtained in step (3) (its molar amount is calculated based on the grafted formula 1) (the molar ratio is: 1.05:1.1:1), the solvent is acetone, dibutyltin dilaurate is added (its amount is 2.5 wt% of the weight of formula 1 in step 3), and the reaction is carried out at 40°C for 3h under a nitrogen atmosphere. After separation and purification, a composite sol is obtained;

[0082] The composite sol prepared above was compounded with hydrofluoroether 3M 7100, and the solid content was adjusted to 26% to obtain a surface treatment agent with strong rigidity.

[0083] Example 4

[0084] This embodiment provides a surface treatment agent with strong rigidity, and the specific preparation method includes the following preparation steps:

[0085] 1) Weigh 3-aminopropyltrimethoxysilane and dissolve it in ethanol. Then add hydrochloric acid and deionized water (molar ratio of 1:30:0.004:1.2, respectively). Mix well in a three-necked flask, heat to 65°C, and reflux for 3 hours to obtain a precursor sol.

[0086] 2) Formula 4 (m=8, n=7) and epichlorohydrin in a molar ratio of 1:1.1 were weighed and added to acetone, and sodium hydroxide (1.5 wt% of the weight of Formula 4) was added. The mixture was heated to 70°C and reacted for 4 hours to obtain a product having the structure of Formula 1 (wherein m and n are 8 and 7, respectively).

[0087] 3) adding the product obtained in step (2) to the polyaminosiloxane sol obtained in step (1) (the molar ratio of amino groups in the polyaminosiloxane sol to Formula 1 is 1:1), stirring at 40° C., heating under reflux for 4 h, performing a ring-opening reaction, and obtaining a grafted modified polysiloxane of Formula 1 after purification;

[0088] 4) Weigh m-xylylene diisocyanate, formula 2D ( ) is added to the modified polysiloxane grafted with formula 1 obtained in step (3) (its molar amount is calculated based on the grafted formula 1) (the molar ratio is 1.09:0.95:1 respectively), the solvent is acetone, di(dodecylthio)dibutyltin is added (its amount is 3.5 wt% of the weight of formula 1 in step 3), and the reaction is carried out at 45°C for 4h under a nitrogen atmosphere. After separation and purification, a composite sol is obtained;

[0089] The composite sol prepared above was compounded with hydrofluoroether 3M 7300, and the solid content was adjusted to 30% to obtain a surface treatment agent with strong rigidity.

[0090] Example 5

[0091] Compared with Example 1, the only difference is that Formula 2A is replaced by Formula 2E (R1 is , R2 is The remaining preparation steps and conditions are the same.

[0092] Comparative Example 1

[0093] Compared with Example 1, the only difference is that step (1) is not performed, but aminopropyltrimethoxysilane is directly reacted with the product obtained in step (2), and the remaining preparation steps and conditions are the same.

[0094] Comparative Example 2

[0095] Compared with Example 1, the only difference is that step (2) is not performed, and in step 3, comparative formula A ( , m and n are both 12) are substituted in equal amounts in formula 1, and the rest of the preparation steps and conditions are the same.

[0096] Comparative Example 3

[0097] Compared with Example 1, the only difference is that the treatment of step (4) is not performed, but Formula 2A is directly added to the product of step (3), and the remaining preparation steps and conditions are the same.

[0098] Comparative Example 4

[0099] Compared with Example 1, the only difference is that in step (4), Formula 2A is replaced by Comparative Formula B (R1 and R2 are The remaining preparation steps and conditions are the same.

[0100] Comparative Example 5

[0101] Compared with Example 1, the only difference is that the silica sol is first modified by Formula 2 and then modified by Formula 1. Specifically, after step 1, the product is directly subjected to step 4, and then steps 2 and 3 are carried out in sequence. Other operations and parameters are the same as in Example 1.

[0102] Comparative Example 6

[0103] Compared with Example 1, the only difference is that steps 2 and 3 are not performed, and step 4 is directly performed after step 1. Other operations and parameters are the same as those in Example 1.

[0104] The surface treatment agents prepared in Examples 1 to 5 and Comparative Examples 1 to 6 were uniformly and precisely applied to the surface of the substrate by spraying, and then cured at 40° C. for 2 hours.

[0105] The adhesion, initial water contact angle, steel wool friction, and water contact angle after alkali immersion of the substrate surface coating were tested to verify the stability, hydrophobicity, antifouling, friction resistance, and corrosion resistance of the surface treatment agents obtained in each example or comparative example. The test results are shown in Table 1 below.

[0106] Light transmittance test method: Light transmittance is measured by TH-110 light transmittance haze meter. Place the coated substrate on the test platform, press the HOLD button of the instrument, and start the test after the instrument passes the self-calibration. Record the test results.

[0107] Pencil hardness: Refer to GB / T 6739-2022 "Paints and varnishes - Determination of film hardness by pencil method": Use the pencil method to measure the hardness of the coating.

[0108] Adhesion: Draw a grid and test with 3M 600 tape 3 times.

[0109] Water Contact Angle Test Method: Static contact angles of coatings were measured using a JGW-360a contact angle meter. The test liquid volume was 2 μL, and the test environment was 24 ± 1°C and 45 ± 1% relative humidity. The water contact angles were measured at five points, and the average value was taken.

[0110] Steel wool abrasion resistance test method: The steel wool abrasion resistance test is measured using a ZJ-339-GSR abrasion tester. The coated substrate is fixed on the tester with the eraser model MUN BANGSAWOO, the pressure is set to 1000g, the stroke is set to 40mm, and the speed is 40 cycles / min. After the test, the water contact angle test results of the substrate are recorded.

[0111] The test results of each case are shown in Table 1:

[0112]

[0113] From the data of Examples 1 to 5, it can be seen that the strong and rigid surface treatment agent exhibits excellent hydrophobic antifouling and mechanical strength, with initial water contact angles of >120° and adhesion of 5B grade. Moreover, after rubbing with steel wool 30k times, its water contact angle is still >110°, showing excellent friction resistance. In addition, it can be found from Examples 1, 2 and Examples 3 and 4 that the surface treatment agent containing hydroxyl group Formula 2 is superior to the surface treatment agent containing amino group or halogen group Formula 2 in terms of wear resistance. The data results of Comparative Example 1 show that the self-condensation step of aminosiloxane is beneficial to improving the adhesion and mechanical strength of the coating. Comparative Example 2 does not adopt Formula 1 described in the present invention, resulting in a smaller initial water contact angle, poor hydrophobic antifouling and friction resistance. The data results of Comparative Examples 3 and 4 show that the addition of Formula 2 compounds that cannot be chemically bonded cannot effectively improve the friction resistance of the coating. Comparative Example 5, due to the reversal of the reaction order, has poor hydrophobicity and wear resistance. Comparative Example 6 only undergoes Formula 2 modification, and has poor hydrophobicity.

[0114] 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, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features thereof can 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 method for preparing a rigid surface treatment agent, characterized in that the steps include: Step 1: The aminosiloxane is polymerized to obtain a polyaminosiloxane sol; and then the polyaminosiloxane sol is subjected to a first-stage grafting reaction with the polysiloxane of Formula 1 to obtain a grafted modified polysiloxane of Formula 1; Formula 1; In formula 1, m and n are integers between 0 and 30, and m and n are not 0 at the same time; Step 2: The modified polysiloxane, Formula 2 and an isocyanate crosslinking agent are subjected to a second-stage grafting reaction to modify Formula 2 on the modified polysiloxane to obtain the rigid surface treatment agent; Formula 2; In formula 2, R1 is H, C1~C 10 Alkyl, C3~C 10 a cycloalkyl or phenyl group; R2 is a substituent having a carbon number of less than 10 and containing a substituent a, wherein the substituent a comprises at least one of a hydroxyl group, an amino group, a halogen group, and a mercapto group.

2. The method for preparing a rigid surface treatment agent according to claim 1, wherein: Aminosiloxane is a compound having the structural formula 3; Formula 3; wherein R3 is a C1~C8 alkylene group or -X1-NH-X2-, wherein X1 and X2 are C1~C8 alkylene groups; R4 is a C1~C8 alkyl group; R5 is at least one of a hydrogen atom, a C1-C8 alkyl group, and a C1-C8 alkoxy group.

3. The method for preparing a rigid surface treatment agent according to claim 1, wherein: Formula 1 is obtained by reacting Formula 4 and Formula 5; Formula 4; In formula 4, m and n are the same as those in formula 1; Formula 5; X is halogen.

4. The method for preparing a rigid surface treatment agent according to claim 1, wherein: The molar ratio of amino group to Formula 1 in the polyaminosiloxane sol is 0.9-1.2:

1.

5. The method for preparing a rigid surface treatment agent according to claim 1, wherein: In formula 2, R1 is a C1~C8 alkyl group; The R2 is a group having the substituent a on a C1-C8 straight carbon chain, an oxygen-hetero straight carbon chain, or a five-membered or six-membered saturated carbon ring.

6. The method for preparing a rigid surface treatment agent according to claim 1, wherein: The molar ratio of formula 2, isocyanate crosslinking agent and formula 1 is 0.3-1.4:0.8-1.2:1; In step 2, an organic Sn catalyst is further added, and the amount of the organic Sn catalyst is 2.0-4.0 wt% of the weight of formula 1.

7. A rigid surface treatment agent obtained by the preparation method according to any one of claims 1 to 6.

8. A coating, characterized in that: The rigid surface treatment agent comprises the preparation method according to any one of claims 1 to 6, and further comprises at least one of a diluent and an auxiliary agent.

9. A coating, characterized in that The method is obtained by coating and drying the coating material according to claim 8.

10. A protective material comprising a substrate to be protected and a coating composited on the surface thereof, characterized in that: The coating is the coating according to claim 9.

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