Environment-friendly latent curing agent and preparation method thereof, environment-friendly polyurethane waterproof coating raw material composition, environment-friendly polyurethane waterproof coating and preparation method thereof

Abstract

The invention relates to the technical field of building waterproof coatings, and discloses an environment-friendly latent curing agent and a preparation method thereof, an environment-friendly polyurethane waterproof coating raw material composition, an environment-friendly polyurethane waterproof coating and a preparation method thereof. The preparation method of the environment-friendly latent curing agent comprises the following steps: (1) in the presence of a solvent, carrying out first mixing on an aldehyde compound and an amine compound to obtain an intermediate I; the aldehyde compound is a combination of an aldehyde compound I and an aldehyde compound II in a content molar ratio of (1-2.5): 1; the aldehyde compound I is benzaldehyde and / or isobutyraldehyde, and the aldehyde compound II is nonanal and / or capraldehyde; and (2) carrying out dehydration condensation reaction on the intermediate I to obtain the environment-friendly latent curing agent. The environment-friendly polyurethane waterproof coating prepared by the preparation method disclosed by the invention has better environment-friendly performance and also has good mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building waterproof coating, and particularly relates to an environmentally-friendly latent curing agent, a preparation method thereof, an environmentally-friendly polyurethane waterproof coating raw material composition, an environmentally-friendly polyurethane waterproof coating and a preparation method thereof. BACKGROUND

[0002] At present, polyurethane has been widely used in various aspects of life. For example, polyurethane adhesive has good low-temperature resistance, oil resistance and wear resistance, and the adhesive film is relatively tough, has good impact resistance and strong bonding force; after adding a flame retardant, hard polyurethane can resist high temperature and is flame-retardant, and is widely used as a fireproof material; the polyurethane board has good heat insulation performance and can be used as a thermal insulation material for building outer walls, which can effectively reduce the thickness of the building outer wall, and the polyurethane material has excellent anti-aging performance and will not easily crack.

[0003] At present, polyurethane materials can be divided into two-component polyurethane and single-component polyurethane. One component of the two-component polyurethane is a hydroxyl-terminated polyol, and the other component is a compound with a terminal group of -NCO. The two components are crosslinked to obtain the two-component polyurethane. The advantages are adjustable performance and fast curing speed, and the disadvantage is unstable performance of the actual product. Single-component polyurethane, referred to as SPU, is directly reacted with water in the air to expand or crosslink to form, compared with the two-component polyurethane. SPU has the advantages of stable performance and simple operation.

[0004] Single-component polyurethane curing has two curing modes, namely moisture curing and latent curing. In the former, the polyurethane prepolymer is directly placed in the air to react with moisture to obtain a urea bond, and the urea bond reacts with the prepolymer to form polyurethane. Although the operation is simple, CO2 is generated in the reaction process, which affects the performance. The latent curing process avoids the generation of CO2 because the latent curing agent will first react with water in a humid environment to form a product, which then reacts with the -NCO group of the prepolymer to obtain the polyurethane prepolymer.

[0005] The commonly used polyurethane latent curing agent has two types, one is imine and the other is oxazolidine. Both of them will hydrolyze in the presence of water to release active reactants (alcohol amine or amine) and capping substances (aldehyde or ketone). The active reactants react with the -NCO group in the single-component polyurethane waterproof coating to cure the product, and the capping substances are released into the environment. Because of this release, the chemical toxicity of the capping substances themselves will cause different degrees of harm to the human body and the environment. The volatilization of these substances contributes to the VOC emission value, and at the same time produces irritating odor, which is very harmful to the health of construction personnel in a relatively closed construction space.

[0006] In addition, most of the single-component polyurethane waterproof coatings currently sold on the domestic market are solvent-based. The addition of organic solvents in the coating is conducive to reducing the viscosity to improve the construction performance. However, with the increase of the amount of organic solvents, the VOC content of the coating is also continuously increased, which does not meet the increasingly stringent environmental protection requirements. Another type of single-component polyurethane waterproof coating does not add a latent curing agent in the formula. Although the VOC content is very low, the construction performance of this type of coating is poor, and the coating film is severely blistering after construction, which cannot meet the actual waterproof requirements.

[0007] Therefore, it is of great significance to develop a new type of environmentally friendly single-component polyurethane waterproof coating. SUMMARY

[0008] The purpose of the present application is to provide an environmentally friendly polyurethane waterproof coating with low VOC content, no blistering during construction and excellent mechanical properties.

[0009] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a method for preparing an environmentally friendly latent curing agent, which comprises: (1) mixing an aldehyde compound and an amine compound in the presence of a solvent to obtain an intermediate I; The molar ratio of the aldehyde compound calculated based on the aldehyde group to the amine compound calculated based on the primary amino group is 1-1.1:1; the aldehyde compound is a combination of aldehyde compound I and aldehyde compound II with a molar ratio of 1-2.5:1; the aldehyde compound I is benzaldehyde and / or isobutyraldehyde, and the aldehyde compound II is nonanal and / or decanal; (2) dehydrating and condensing the intermediate I to obtain the environmentally friendly latent curing agent.

[0010] The second aspect of the present application provides an environmentally friendly latent curing agent prepared by the method of the aforementioned first aspect.

[0011] The third aspect of the present application provides an environmentally friendly polyurethane waterproof coating raw material composition, which is composed of a main agent and an auxiliary agent. The main agent comprises a polyether diol, a polyether triol, a diisocyanate, an adsorbent and a latent curing agent. The content of the polyether triol is 35-65 parts by weight, the content of the diisocyanate is 20-30 parts by weight, the content of the adsorbent is 8-12 parts by weight, and the content of the latent curing agent is 3-8 parts by weight, relative to 100 parts by weight of the polyether diol; The latent curing agent is the environmentally friendly latent curing agent of the aforementioned second aspect.

[0012] The fourth aspect of the present application provides a method for preparing an environmentally friendly polyurethane waterproof coating, which applies each component in the composition of the aforementioned third aspect. The method comprises: S1, polyether diol, polyether triol and part of the auxiliary agent are mixed to obtain a mixture I; S2, diisocyanate is mixed with the mixture I treated by dehydration to obtain a mixture II; S3, the latent curing agent is mixed with the mixture II to obtain a mixture III; S4, the remaining auxiliary agent is mixed with the mixture III to obtain the environmentally friendly polyurethane waterproof coating.

[0013] The fifth aspect of the present application provides an environmentally friendly polyurethane waterproof coating prepared by the method of the fourth aspect.

[0014] Through the above technical solution, the present application has at least the following beneficial technical effects: (1) The environmentally friendly latent curing agent provided by the present application is used in polyurethane waterproof coating, and the deblocking speed is suitable, which does not affect the curing speed of the waterproof coating, and the volatility is low.

[0015] (2) The environmentally friendly polyurethane waterproof coating provided by the present application can realize the excellent effect of no obvious irritating odor and low VOC emission value through the synergistic effect of the specially prepared environmentally friendly latent curing agent, adsorbent, odor removal agent and filler and other main components.

[0016] (3) The environmentally friendly polyurethane waterproof coating provided by the present application can be well constructed without blistering in a high temperature and high humidity environment, and also has excellent mechanical properties. DETAILED DESCRIPTION

[0017] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values and should be understood to include values approximately near these ranges and values within these ranges. For ranges with endpoints, the endpoints are included in the ranges. For ranges with endpoints, the endpoints are included in the ranges. The endpoints of the ranges and the individual values are not to be construed as limiting the range or the values. Ranges can be expressed in a variety of ways. For example, a range of "between A and B" can be expressed as greater than A and less than B; from A to B; greater than A or less than B; greater than A or equal to B; less than B or equal to A; A and B; or A to B. Language such as "up to" can indicate the upper limit of a range, and language such as "at least" can indicate the lower limit of a range. Likewise, the expressions "about" and "approximately" can indicate that a value is within a certain tolerance range of a value.

[0018] As described above, the first aspect of the present application provides a method for preparing an environmentally friendly latent curing agent, which comprises: (1) in the presence of a solvent, the aldehyde compound and the amine compound are mixed to obtain intermediate I; The molar ratio of the aldehyde compound to the primary amino group of the amine compound is 1-1.1:1; the aldehyde compound is a combination of aldehyde compound I and aldehyde compound II with a molar ratio of 1-2.5:1; the aldehyde compound I is benzaldehyde and / or isobutyraldehyde, and the aldehyde compound II is nonanal and / or decanal; (2) performing a dehydration condensation reaction on the intermediate I to obtain the environmentally-friendly latent curing agent.

[0019] In the present application, the meaning of "the amount of the aldehyde compound based on the aldehyde group and the amount of the amine compound based on the primary amino group" is that the amount of the aldehyde compound is calculated based on the amount of aldehyde group (-CHO) in the aldehyde compound, and the amount of the amine compound is calculated based on the amount of primary amino group (-NH2) in the amine compound.

[0020] According to a preferred embodiment, the aldehyde compound I is a combination of benzaldehyde and isobutyraldehyde with a molar ratio of 1:1-5, and the aldehyde compound II is a combination of nonanal and decanal with a molar ratio of 1:1-3. The inventors of the present application have found that in this preferred case, the environmentally-friendly polyurethane waterproof coating provided by the present application has a lower VOC emission value and a more suitable deblocking speed.

[0021] According to a specific embodiment, the conditions of the first mixing include a temperature of 25-45℃, a time of 1-3h, and a rotation speed of 150-200rpm.

[0022] According to a specific embodiment, the conditions of the dehydration condensation reaction include a temperature of 120-130℃.

[0023] Preferably, the solvent is toluene and / or xylene.

[0024] Preferably, the amount of the solvent is 5-10wt% based on the total mass of the solvent, the aldehyde compound and the amine compound.

[0025] Preferably, the amine compound is a diamine compound.

[0026] More preferably, the amine compound is selected from at least one of ethylenediamine, hexamethylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 2-methylpentanediamine, diethylamine, dibutylamine and isophorone diamine.

[0027] According to a specific embodiment, in the first mixing, 0.2-1wt% of a catalyst can also be added based on the total mass of the solvent, the aldehyde compound and the amine compound, and the catalyst is preferably toluene sulfonic acid.

[0028] The present application does not have a specific requirement for the time of the dehydration condensation reaction, and those skilled in the art can ensure that the moisture in the reaction system is completely discharged, and for example, the time of the dehydration condensation reaction is 1-5h.

[0029] According to a specific embodiment, after the dehydration condensation reaction, the pre-product obtained after the dehydration condensation reaction is subjected to vacuum distillation to obtain the environmentally friendly latent curing agent; preferably, the conditions of the vacuum distillation include: temperature of 130-140℃, pressure of -0.02MPa to 0.05MPa, time of 0.5-1h.

[0030] According to a preferred embodiment, the method for preparing the environmentally friendly latent curing agent comprises the following steps: (1) at 25-45℃, an amine compound, a solvent and a catalyst are added into a round-bottom flask, stirred and mixed for 5-10min, then an aldehyde compound is added dropwise into the round-bottom flask, after the dropwise addition is completed, stirring is continued for 1-3h to obtain an intermediate I; (2) the temperature is raised to 120-130℃, and kept under reflux to perform a dehydration condensation reaction, after 1-5h, the amount of water outflow reaches the theoretical amount of water (the theoretical amount of water is in a molar ratio of 1:0.8-1 to the mixed aldehyde); then vacuum distillation is performed at 130-140℃ and -0.02 to 0.05MPa for 0.5-1h to obtain the environmentally friendly latent curing agent.

[0031] As described above, the second aspect of the present application provides an environmentally friendly latent curing agent prepared by the method of the first aspect.

[0032] As described above, the third aspect of the present application provides an environmentally friendly polyurethane waterproof coating raw material composition, which comprises a main agent and an auxiliary agent, wherein the main agent comprises a polyether diol, a polyether triol, a diisocyanate, an adsorbent and a latent curing agent. The content of the polyether triol is 35-65 parts by weight, the content of the diisocyanate is 20-30 parts by weight, the content of the adsorbent is 8-12 parts by weight, and the content of the latent curing agent is 3-8 parts by weight, relative to 100 parts by weight of the polyether diol. The latent curing agent is the environmentally friendly latent curing agent of the second aspect.

[0033] According to a specific embodiment, the diisocyanate is at least one selected from toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate.

[0034] According to a specific embodiment, the adsorbent is at least one selected from aluminum oxide, zinc oxide, magnesium oxide, molecular sieve, activated clay and activated carbon.

[0035] According to a specific embodiment, the auxiliary agents include plasticizers, odor-removing agents and fillers; the content of the plasticizers is 90-120 parts by weight, the content of the odor-removing agents is 2-5 parts by weight, and the content of the fillers is 130-200 parts by weight, relative to 100 parts by weight of the polyether diols.

[0036] Preferably, the plasticizers are selected from at least one of vegetable oil-based, tricoctyl phosphate, citrate ester and chlorinated paraffin.

[0037] Preferably, the odor-removing agents are selected from at least one of N-acetylglycine, N-acetylalanine, glycine methyl ester and alanine ethyl ester.

[0038] Preferably, the fillers are selected from at least one of nano calcium carbonate, talc powder, fumed silica, heavy calcium, kaolin, wollastonite powder, mica powder, titanium dioxide and carbon black.

[0039] According to a specific embodiment, the auxiliary agents further include hydrolysis promoters and catalysts; the content of the hydrolysis promoters is 0.2-1 parts by weight, and the content of the catalysts is 0.2-0.8 parts by weight, relative to 100 parts by weight of the polyether diols.

[0040] Preferably, the hydrolysis promoters are selected from at least one of benzoic acid, salicylic acid, acetic acid, p-toluenesulfonic acid and citric acid.

[0041] Preferably, the catalysts are selected from at least one of dibutyltin dilaurate, stannous octoate, triethylamine, dimethylethanolamine, N,N-dimethylbenzylamine and bismuth isooctoate.

[0042] As described above, the fourth aspect of the present application provides a method for preparing the environmentally-friendly polyurethane waterproof coating, which applies the components in the composition of the third aspect described above, and the method comprises the following steps: S1, mixing polyether diols, polyether triols and part of the auxiliary agents to obtain a mixture I; S2, stirring and mixing diisocyanate with the dehydrated mixture I to obtain a mixture II; S3, stirring and reacting latent curing agents with the mixture II to obtain a mixture III; S4, mixing and processing the remaining auxiliary agents with the mixture III to obtain the environmentally-friendly polyurethane waterproof coating.

[0043] According to a specific embodiment, the method for preparing the environmentally-friendly polyurethane waterproof coating comprises the following steps: 1) Under the conditions of temperature 20-40℃ and rotation speed 1000-2000rpm, polyether diol, polyether triol, plasticizer, adsorbent, odor-removing agent and filler were mixed by contact for 20-40min to obtain mixture I; 2) The mixture I was subjected to dehydration treatment at 100-110℃ and -0.08 to -0.1MPa for 2-3h; 3) Under the conditions of temperature 70-80℃, diisocyanate and catalyst (1 / 4 to 1 / 2 of the formula amount) were mixed with the mixture I, the temperature was increased by 5-10℃, and the mixing was continued for 3-4h to obtain mixture II; 4) The temperature was kept unchanged, and the environmentally-friendly latent curing agent was mixed with the mixture II for 0.5-1h to obtain mixture III; 5) Under the conditions of temperature 50-60℃, the remaining amount of catalyst and hydrolysis promoter were mixed with the mixture III for 0.5-1h, and the environmentally-friendly polyurethane waterproof coating was obtained after cooling.

[0044] As described above, the fifth aspect of the present application provides the environmentally-friendly polyurethane waterproof coating prepared by the method of the aforementioned fourth aspect.

[0045] The present application will be described in detail by examples as follows. In the following examples, various instruments and raw materials used are all commercially available unless otherwise specified.

[0046] Some raw materials used in the following examples and their sources are as follows: Polyether diol: functionality 2, number average molecular weight 2000, brand DL-2000D, purchased from Shandong Lansheng Dongda Co., Ltd; Polyether triol: functionality 3, number average molecular weight 5000, brand EP330N, purchased from Shandong Lansheng Dongda Co., Ltd.

[0047] The following preparation examples are used to illustrate the preparation of the environmentally-friendly latent curing agent provided by the present application, specifically: Preparation Example 1 (1) At 40℃, 2mol of ethylenediamine, 0.35mol of toluene and 0.007mol of toluenesulfonic acid were added into a round-bottom flask, and stirred and mixed for 10min, then the mixed aldehyde (a mixture of 1mol of benzaldehyde, 1.1mol of isobutyraldehyde, 1mol of nonyl aldehyde and 1mol of decyl aldehyde) was added dropwise into the round-bottom flask, and after the dropwise addition was completed, the stirring was continued for 2h to obtain intermediate I; (2) The temperature is raised to 120°C, and dehydration condensation reaction is carried out under reflux. After 1.5 hours, the amount of water outflow reaches the theoretical amount of water (the theoretical amount of water is in a molar ratio of 1:1 to the mixed aldehyde); then, vacuum distillation is carried out at 130°C and -0.02 MPa for 1 hour to obtain the environmentally friendly latent curing agent-I.

[0048] Preparation Example 2 (1) At 30°C, 2 mol of m-phenylenediamine, 0.5 mol of dimethylbenzene, and 0.007 mol of toluenesulfonic acid are added to a round-bottom flask, and the mixture is stirred for 10 minutes. Then, the mixed aldehyde (the mixed aldehyde is a mixture of 0.5 mol of benzaldehyde, 1.6 mol of isobutyraldehyde, 1 mol of nonanal, and 1 mol of decanal) is added dropwise to the round-bottom flask. After the dropwise addition is completed, stirring is continued for 2.5 hours to obtain the intermediate I; (2) The temperature is raised to 130°C, and dehydration condensation reaction is carried out under reflux. After 2 hours, the amount of water outflow reaches the theoretical amount of water (the theoretical amount of water is in a molar ratio of 1:1 to the mixed aldehyde); then, vacuum distillation is carried out at 140°C and -0.02 MPa for 0.5 hours to obtain the environmentally friendly latent curing agent-II.

[0049] Preparation Example 3 This preparation example is carried out by using a method similar to that of Preparation Example 1, except that in step (1), the composition of the mixed aldehyde is adjusted to be a mixture of 0.3 mol of benzaldehyde, 1.8 mol of isobutyraldehyde, 0.4 mol of nonanal, and 1.6 mol of decanal. The remaining operations are the same as those of Preparation Example 1, and the environmentally friendly latent curing agent-III is prepared.

[0050] Preparation Example 4 This preparation example is carried out by using a method similar to that of Preparation Example 1, except that in step (1), the composition of the mixed aldehyde is adjusted to be a mixture of 2.1 mol of benzaldehyde and 2 mol of nonanal. The remaining operations are the same as those of Preparation Example 1, and the environmentally friendly latent curing agent-IV is prepared.

[0051] Comparative Preparation Example 1 This comparative preparation example is carried out by using a method similar to that of Preparation Example 1, except that in step (1), the composition of the mixed aldehyde is adjusted to be a mixture of 2.5 mol of benzaldehyde, 0.6 mol of isobutyraldehyde, 0.5 mol of nonanal, and 0.5 mol of decanal. The remaining operations are the same as those of Preparation Example 1, and the environmentally friendly latent curing agent-DI is prepared.

[0052] Comparative Preparation Example 2 The comparative preparation example is prepared by using the similar method of preparation example 1, except that in step (1), the amount of ethylenediamine is adjusted to 3 mol, and the rest of the operation is the same as preparation example 1, to prepare the environmentally friendly latent curing agent-DII.

[0053] Comparative preparation example 3 The comparative preparation example is prepared by using the similar method of preparation example 4, except that in step (1), equal amount of formaldehyde is used to replace benzaldehyde, and equal amount of pentanal is used to replace nonanal, and the rest of the operation is the same as preparation example 1, to prepare the environmentally friendly latent curing agent-DIII.

[0054] The embodiments of the present application are used to illustrate the preparation of environmentally friendly polyurethane waterproof coating, and the amount of raw materials in the following examples is by weight unless otherwise specified, and each weight part represents 10 g.

[0055] Example 1 1) Under the conditions of temperature 30℃ and rotation speed 1500rpm, polyether diol, polyether triol, plasticizer, adsorbent, odor removal agent and filler are mixed, the mixing time is 40min, to obtain mixture I; 2) The mixture I is dehydrated at 100℃ and-0.1MPa for 3h; 3) At 70℃, diisocyanate, catalyst (1 / 3 of the formula amount) and the mixture I are mixed, the temperature is adjusted to 80℃, and the mixing is continued for 3h, to obtain mixture II; 4) The temperature is kept unchanged, the environmentally friendly latent curing agent is mixed with the mixture II for 0.5h, to obtain mixture III; 5) The temperature is adjusted to 50℃, the catalyst (the remaining amount) and the hydrolysis promoter are mixed with the mixture III for 1h, and the environmentally friendly polyurethane waterproof coating is obtained after cooling.

[0056] The specific substance types and amounts of the present embodiment are shown in Table 1.

[0057] In the absence of special instructions, example 2 is prepared by referring to the method of example 1, except that the substance types, amounts and process parameters used in the examples are not the same, which are shown in Table 1.

[0058] Table 1

[0059] Example 3 The present embodiment is prepared by using the similar method of example 1, except that equal weight parts of environmentally friendly latent curing agent-III are used to replace the environmentally friendly latent curing agent-I in example 1, and the rest of the operation is the same as example 1, to prepare environmentally friendly polyurethane waterproof coating-III.

[0060] Example 4 This example was prepared by using the similar method of Example 1, except that the environmentally friendly latent curing agent-I in Example 1 was replaced by the environmentally friendly latent curing agent-IV in equal weight parts, and the rest of the operation was the same as Example 1, to prepare the environmentally friendly polyurethane waterproof coating-IV.

[0061] Comparative Example 1 This comparative example was prepared by using the similar method of Example 1, except that the environmentally friendly latent curing agent-I in Example 1 was replaced by the environmentally friendly latent curing agent-DI in equal weight parts, and the rest of the operation was the same as Example 1, to prepare the environmentally friendly polyurethane waterproof coating-DI.

[0062] Comparative Example 2 This comparative example was prepared by using the similar method of Example 1, except that the environmentally friendly latent curing agent-I in Example 1 was replaced by the environmentally friendly latent curing agent-DII in equal weight parts, and the rest of the operation was the same as Example 1, to prepare the environmentally friendly polyurethane waterproof coating-DII.

[0063] Comparative Example 3 This comparative example was prepared by using the similar method of Example 1, except that the environmentally friendly latent curing agent-I in Example 1 was replaced by the environmentally friendly latent curing agent-DIII in equal weight parts, and the rest of the operation was the same as Example 1, to prepare the environmentally friendly polyurethane waterproof coating-DIII.

[0064] Comparative Example 4 This comparative example was prepared by using the similar method of Example 1, except that no environmentally friendly latent curing agent was added, and the rest of the operation was the same as Example 1, to prepare the environmentally friendly polyurethane waterproof coating-DIV.

[0065] Test Example This test example was used to illustrate the performance test of the environmentally friendly polyurethane waterproof coating prepared by each of the above examples and comparative examples.

[0066] Among them, the construction odor test: 200g of the above prepared waterproof coating sample was scraped on a 30cm×50cm glass plate, then transferred to a closed fume hood for curing, and cured at a temperature of (23±2)℃ and a humidity of (50±10)% for 24h, then the air smell in the fume hood was opened.

[0067] Thick coating blister resistance: tested according to the standard of JC / T 2435-2018.

[0068] The dry time, dry time, tensile strength, elongation at break, tear strength, adhesion strength, volatile organic compound content, and water impermeability were tested according to the method of GB / T 19250-2013.

[0069] The specific test results are shown in Table 2.

[0070] Table 2

[0071] As can be seen from the results in Table 2, the environment-friendly polyurethane waterproof coating provided by the present application has better environmental protection performance, and at the same time has good mechanical properties and bonding strength.

[0072] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all fall within the protection scope of the present application.

Claims

1. A method for preparing an environmentally friendly latent curing agent, characterized by, The method comprises: (1) mixing an aldehyde compound and an amine compound in the presence of a solvent to obtain an intermediate I; The molar ratio of the aldehyde compound to the amine compound is 1-1.1:1, the aldehyde compound is a combination of aldehyde compound I and aldehyde compound II, the molar ratio of the aldehyde compound I to the aldehyde compound II is 1-2.5:1, the aldehyde compound I is benzaldehyde and / or isobutyraldehyde, and the aldehyde compound II is nonanal and / or decanal; (2) performing a dehydration condensation reaction on the intermediate I to obtain the environmentally friendly latent curing agent.

2. The method of claim 1, wherein, The aldehyde compound I is a combination of benzaldehyde and isobutyraldehyde with a molar ratio of 1:1-5, and the aldehyde compound II is a combination of nonanal and decanal with a molar ratio of 1:1-3.

3. The method of claim 1, wherein, The conditions of the first mixing include a temperature of 25-45°C, a time of 1-3h, and a rotation speed of 150-200rpm; And / or, the conditions of the dehydration condensation reaction include a temperature of 120-130°C.

4. The method of any of claims 1-3, wherein, The solvent is toluene and / or xylene; And / or, the amine compound is a diamine compound; Preferably, the amine compound is at least one selected from ethylenediamine, hexamethylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 2-methylpentanediamine, diethylamine, dibutylamine, and isophorone diamine.

5. An environmentally friendly latent curing agent prepared by the method of any one of claims 1-4.

6. An environmentally friendly polyurethane waterproof coating raw material composition, characterized by, The composition is composed of a main agent and an auxiliary agent, the main agent includes polyether diol, polyether triol, diisocyanate, adsorbent, and latent curing agent; The content of the polyether triol is 35-65 parts by weight, the content of the diisocyanate is 20-30 parts by weight, the content of the adsorbent is 8-12 parts by weight, and the content of the latent curing agent is 3-8 parts by weight, relative to 100 parts by weight of the polyether diol; The latent curing agent is the environmentally friendly latent curing agent of claim 5.

7. The composition of claim 6, wherein, The diisocyanate is at least one selected from toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate; And / or, the adsorbent is at least one selected from aluminum oxide, zinc oxide, magnesium oxide, molecular sieve, activated clay, and activated carbon.

8. The composition according to claim 6 or 7, wherein, The auxiliary agent includes plasticizer, odor removal agent, and filler; the content of the plasticizer is 90-120 parts by weight, the content of the odor removal agent is 2-5 parts by weight, and the content of the filler is 130-200 parts by weight, relative to 100 parts by weight of the polyether diol; And / or, the plasticizer is at least one selected from vegetable oil base, tricoctyl phosphate, citric acid ester, and chlorinated paraffin; And / or, the odor removal agent is at least one selected from N-acetylglycine, N-acetylalanine, glycine methyl ester, and alanine ethyl ester.

9. A method for preparing an environmentally friendly polyurethane waterproof coating, characterized by, The method applies each component in the composition of any one of claims 6-8, and the method comprises: S1, contacting and mixing polyether diol, polyether triol, and part of the auxiliary agent to obtain a mixture I; S2, stirring and mixing diisocyanate with the dehydrated mixture I to obtain a mixture II; S3, stirring and reacting the latent curing agent with the mixture II to obtain a mixture III; S4, mixing the remaining auxiliary agent with the mixture III to obtain the environment-friendly polyurethane waterproof coating.

10. The environment-friendly polyurethane waterproof coating prepared by the method of claim 9.

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