Aqueous blocked isocyanate curing agent, its preparation method and application in waterproof finishing of fabric

Abstract

This invention belongs to the technical field of water-based curing agents in the textile industry, and provides a water-based blocked isocyanate curing agent, its preparation method, and its application in waterproof finishing of fabrics. The invention involves mixing polyisocyanate, hydroxy acrylate, and solvent for polymerization. A blocking agent is added to the resulting polymerization system to perform an end-capping reaction, yielding a blocked isocyanate. The blocked isocyanate, long-chain alkyl acrylate, POSS cage-like polysilsesquioxane hydrophobic modifier, chain transfer agent, initiator, and solvent are mixed for free radical addition reaction to obtain a hydrophobically modified blocked isocyanate. The hydrophobically modified blocked isocyanate, emulsifier, pH adjuster, water, and co-solvent are mixed and subjected to high-pressure homogenization to obtain a water-based blocked isocyanate curing agent. The water-based blocked isocyanate curing agent of this invention has enhanced waterproofing properties. When combined with a fluorine-free waterproofing agent, it can improve the waterproofing and wash resistance of the fluorine-free waterproofing agent.

Description

Technical Field

[0001] This invention relates to the field of water-based curing agents in the textile industry, and particularly to a water-based blocked isocyanate curing agent, its preparation method, and its application in waterproof finishing of fabrics. Background Technology

[0002] Blocked isocyanate curing agents are produced by pre-reacting isocyanates with compounds containing active hydrogen, protecting the isocyanate ions and preventing them from reacting with compounds containing active groups at room temperature. When the temperature rises to the desealing temperature, the isocyanate ions are released, allowing them to continue reacting with compounds containing active groups. Blocked isocyanates are environmentally friendly, safe, easy to transport and store, and have high production efficiency, making them widely used in the automotive, textile, and other industries.

[0003] However, most current water-based blocked isocyanate curing agents are modified directly using hydrophilic chain extenders, followed by blocking with a blocking agent. Because the functional groups in these blocked isocyanates are currently low and they haven't undergone hydrophobic modification, their initial gain on fabric waterproofing is insufficient, and their wash resistance is poor. For example: Patent CN115698221A discloses a method for producing water-based blocked isocyanate that can be used to enhance the waterproofing effect of fabrics. This method uses polyoxyethylene monomethyl ether (MPEG) for hydrophilic modification and then seals the ends with a blocking agent. Because the introduction of hydrophilic MPEG reduces the number of cross-linking functional groups of the polyisocyanate, its waterproofing effect and wash resistance will be worse when combined with fabric waterproofing agents.

[0004] Patent CN103351460A describes an N-methyldiethanolamine-modified waterborne blocked isocyanate as a synergist for waterproofing fabrics and improving wash resistance. However, this blocked isocyanate has limited initial synergistic effect on waterproofing agents.

[0005] Patent CN102432801A describes a waterborne blocked isocyanate modified with polyether polyol and N-methyldiethanolamine for use as a waterproofing enhancer and to improve wash resistance of fabrics. However, polyether polyol itself has certain hydrophilic properties, which will inevitably affect its waterproofing performance. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a water-based closed-cell isocyanate curing agent, its preparation method, and its application in waterproof finishing of fabrics. The water-based closed-cell isocyanate curing agent prepared by the method provided by this invention has waterproofing synergistic properties, and when combined with a fluorine-free waterproofing agent, it can improve the waterproofness and wash resistance of the fluorine-free waterproofing agent.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing an aqueous blocked isocyanate curing agent, comprising the following steps: Polyisocyanate, hydroxy acrylate and solvent are mixed and polymerized. A blocking agent is added to the resulting polymerization system to carry out an end-capping reaction, thereby obtaining a blocked isocyanate. The blocked isocyanate, long-chain alkyl acrylate, POSS cage-like polysilsesquioxane hydrophobic modifier, chain transfer agent, initiator and solvent are mixed and subjected to free radical addition reaction to obtain hydrophobically modified blocked isocyanate. The hydrophobically modified blocked isocyanate, emulsifier, pH adjuster, water and cosolvent are mixed and homogenized under high pressure to obtain the water-based blocked isocyanate curing agent.

[0008] Preferably, the polyisocyanate comprises at least one selected from hexamethylene diisocyanate trimer, hexamethylene diisocyanate biuret, isophorone diisocyanate trimer, polymethylene polyphenyl isocyanate, and toluene diisocyanate-trimethylolpropane adduct; The hydroxy acrylates include one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate; The mass ratio of the polyisocyanate to the hydroxyacrylate is 10~20:1~3.

[0009] Preferably, the polymerization reaction is carried out at a temperature of 40~80℃ for a time of 0.5~1.5h.

[0010] Preferably, the blocking agent comprises one or more of methyl ethyl ketone oxime, acetone oxime, diethyl malonate, and 3,5-dimethylpyrazole; The mass ratio of the polyisocyanate to the blocking agent is 10~20:3~8; The end-capping reaction is carried out at a temperature of 40~80℃ for a time of 0.5~1.5h.

[0011] Preferably, the long-chain alkyl acrylate includes one or more of hexadecyl acrylate, octadecyl acrylate, hexadecyl methacrylate, octadecyl methacrylate, and dodecyl acrylate; the mass ratio of the polyisocyanate to the long-chain alkyl acrylate is 10~20:1~5; The POSS cage-like polysilsesquioxane hydrophobic modifier has the structure shown in Formula 1: Formula 1; In Equation 1, Si-R1 is , and One or more of the following; Si-R2 is ; The mass ratio of the polyisocyanate to the POSS cage-like polysilsesquioxane hydrophobic modifier is 10~20:5~10; The chain transfer agent comprises dodecyl mercaptan, and the added mass of the chain transfer agent is 0.05~0.3% of the total mass of the polyisocyanate, hydroxy acrylate, blocking agent, long-chain alkyl acrylate and POSS cage-like polysilsesquioxane hydrophobic modifier; The initiator includes azobisisobutyronitrile, and the mass of the initiator added is 0.1 to 0.4% of the total mass of the polyisocyanate, hydroxy acrylate, blocking agent, long-chain alkyl acrylate and POSS cage-like polysilsesquioxane hydrophobic modifier.

[0012] Preferably, the free radical addition reaction is carried out at a temperature of 70-80°C for 2-4 hours.

[0013] Preferably, the emulsifier comprises a nonionic emulsifier or a cationic emulsifier, wherein the nonionic emulsifier comprises isomeric tridecyl alcohol polyoxyethylene ether and / or castor oil polyoxyethylene ether; the cationic emulsifier comprises one or more of ammonium chloride containing aliphatic segments, aliphatic tertiary amines, and amide emulsifiers, wherein the ammonium chloride containing aliphatic segments comprises one or more of dicocoyl ammonium chloride and octadecyl stearyl ammonium chloride; and the mass ratio of the polyisocyanate to the emulsifier is 10~20:2~5. The co-solvent includes one or more of dipropylene glycol, tripropylene glycol, ethylene glycol butyl ether, diethylene glycol butyl ether, dipropylene glycol butyl ether, and dipropylene glycol methyl ether; the mass ratio of the polyisocyanate to the co-solvent is 10~20:5~10; The pH adjuster includes an acid; The mass ratio of the polyisocyanate to water is 10~20:50~70.

[0014] Preferably, the pressure of the high-pressure homogenization is 20~50MPa, the pH value of the system is 3~6, ​​and the number of high-pressure homogenization cycles is 3~5.

[0015] The present invention also provides an aqueous blocked isocyanate curing agent prepared by the preparation method described above, wherein the solid content of the aqueous blocked isocyanate curing agent is 20-30%.

[0016] The present invention also provides the application of the water-based closed-type isocyanate curing agent described in the above technical solution in the waterproof finishing of fabrics.

[0017] This invention provides a method for preparing an aqueous blocked isocyanate curing agent.

[0018] The preparation method provided by this invention modifies the blocked isocyanate by introducing a POSS cage-like polysilsesquioxane hydrophobic modifier and long-chain alkyl acrylates; simultaneously, it uses a combination of internal and external emulsification to prepare a water-based blocked isocyanate curing agent. The water-based blocked isocyanate curing agent of this invention can improve the initial waterproof performance and washability of fabrics, while also exhibiting excellent storage stability. Detailed Implementation

[0019] This invention provides a method for preparing an aqueous blocked isocyanate curing agent, comprising the following steps: Polyisocyanate, hydroxy acrylate and solvent are mixed and polymerized. A blocking agent is added to the resulting polymerization system to carry out an end-capping reaction, thereby obtaining a blocked isocyanate. The blocked isocyanate, long-chain alkyl acrylate, POSS cage-like polysilsesquioxane hydrophobic modifier, chain transfer agent, initiator and solvent are mixed and subjected to free radical addition reaction to obtain hydrophobically modified blocked isocyanate. The hydrophobically modified blocked isocyanate, emulsifier, pH adjuster, water and cosolvent are mixed and homogenized under high pressure to obtain the water-based blocked isocyanate curing agent.

[0020] Unless otherwise specified, the raw materials used in this invention are preferably commercially available products.

[0021] This invention involves mixing polyisocyanate, hydroxy acrylate, and solvent to carry out a polymerization reaction.

[0022] In this invention, the polyisocyanate preferably includes one or more of hexamethylene diisocyanate trimer (HDI trimer), hexamethylene diisocyanate biuret, isophorone diisocyanate trimer, polymethylene polyphenyl isocyanate (PAPI), and toluene diisocyanate-trimethylolpropane adduct (TDI-TMP).

[0023] In this invention, the hydroxyacrylate preferably includes one or more of hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), hydroxyethyl methacrylate (HEMA), and hydroxypropyl methacrylate (HEPA).

[0024] In this invention, the solvent preferably includes one or more of ethyl acetate (EA), butanone, or methyl isobutyl ketone (MIBK).

[0025] In this invention, the mass ratio of the polyisocyanate to the hydroxy acrylate is preferably 10~20:1~3, more preferably 5~20:1, and specifically preferably 50:8 (6.25:1), 120:8 (15:1) or 72:8 (9:1).

[0026] In this invention, the mass ratio of polyisocyanate to solvent in the reaction solution of the polymerization reaction is preferably 50~150:100, and more preferably 50:100, 120:100 or 72:100.

[0027] In this invention, the polymerization reaction temperature is preferably 40~80℃, more preferably 60℃, and specifically preferably 40℃, 50℃, 60℃, 70℃ or 80℃; the time is preferably 0.5~1.5h, more preferably 1h. In this invention, the polymerization reaction is preferably carried out under stirring and reflux conditions.

[0028] After the polymerization reaction, the present invention preferably obtains the polymerization reaction system directly without any post-processing.

[0029] After obtaining the polymerization reaction system, the present invention adds a blocking agent to the obtained polymerization reaction system to carry out an end-capping reaction to obtain a blocked isocyanate.

[0030] In this invention, the blocking agent preferably includes one or more of methyl ethyl ketone oxime (MEKO), acetone oxime, diethyl malonate, and 3,5-dimethylpyrazole (DMP). In this invention, the mass ratio of the polyisocyanate to the blocking agent is preferably 10-20:3-8, more preferably 1.5-6:1, and specifically preferably 50:27 (1.85:1), 120:27 (4.44:1), or 72:30 (2.4:1).

[0031] In this invention, the sealing agent is preferably added by dripping, and the dripping rate is preferably 100~400g / h, more preferably 200g / h.

[0032] In this invention, the temperature of the end-capping reaction is preferably the same as the temperature of the polymerization reaction described in the above technical solution, and will not be repeated here. In this invention, the time of the end-capping reaction is preferably 0.5~1.5h, more preferably 1h; the time of the end-capping reaction is preferably started from after the sealing agent is completely added.

[0033] In this invention, during the capping reaction, it is preferable to sample and detect the molar content of isocyanate groups (NCO) in the system. Reaching a set value is sufficient, with essentially zero representing the reaction endpoint. In this invention, the preferred method for testing NCO is the di-n-butylamine method, specifically referring to GB / T HG_T 2409-2023: This method utilizes the reaction of isocyanate groups with excess di-n-butylamine to produce urea, followed by titration of the excess di-n-butylamine with hydrochloric acid to quantitatively calculate the isocyanate group content.

[0034] Following the capping reaction, the present invention preferably obtains the blocked isocyanate directly without any post-processing. In the present invention, the blocked isocyanate preferably contains a solvent.

[0035] After obtaining the blocked isocyanate, the present invention mixes the blocked isocyanate, long-chain alkyl acrylate, POSS cage-like polysilsesquioxane hydrophobic modifier, chain transfer agent, initiator and solvent, and performs a free radical addition reaction to obtain hydrophobically modified blocked isocyanate.

[0036] In this invention, the long-chain alkyl acrylate preferably includes one or more of hexadecyl acrylate, octadecyl acrylate (SA), hexadecyl methacrylate, octadecyl methacrylate, and dodecyl acrylate. In this invention, the mass ratio of the polyisocyanate to the long-chain alkyl acrylate is preferably 10-20:1-5, more preferably 2-15:1, and specifically preferably 50:20 (2.5:1), 120:20 (6:1), or 72:20 (3.6:1).

[0037] In this invention, the POSS cage-like polysilsesquioxane hydrophobic modifier preferably has the structure shown in Formula 1: Formula 1; In Equation 1, Si-R1 is , and One or more of the following; Si-R2 is .

[0038] In this invention, the POSS cage-like polysilsesquioxane hydrophobic modifier preferably includes one or more of monoacryloyloxypropylheptaisobutyl cage-like polysilsesquioxane (POSS301), methacryloyloxypropylheptaisobutyl cage-like polysilsesquioxane (POSS302), and vinylheptaisobutyl cage-like polysilsesquioxane (POSS306). In this invention, the mass ratio of the polyisocyanate to the POSS cage-like polysilsesquioxane hydrophobic modifier is preferably 10~20:5~10, more preferably 1~3:1, and specifically preferably 50:50 (1:1), 120:50 (2.4:1), or 72:50 (1.44:1).

[0039] In this invention, the chain transfer agent preferably comprises dodecyl mercaptan, and the added mass of the chain transfer agent is preferably 0.05-0.3% of the total mass of the polyisocyanate, hydroxy acrylate, blocking agent, long-chain alkyl acrylate and POSS cage-like polysilsesquioxane hydrophobic modifier, more preferably 0.05-0.15%, and specifically preferably 0.05%, 0.09%, 0.1%, 0.11%, 0.13%, 0.15%, 0.18%, 0.20%, 0.25% or 0.3%.

[0040] In this invention, the initiator preferably comprises azobisisobutyronitrile (AIBN). In this invention, the added mass of the initiator is preferably 0.1-0.4% of the total mass of the polyisocyanate, hydroxyacrylate, blocking agent, long-chain alkyl acrylate, and POSS cage-like polysilsesquioxane hydrophobic modifier, more preferably 0.1-0.2%, and specifically preferably 0.1%, 0.13%, 0.15%, 0.16%, 0.19%, 0.2%, 0.25%, 0.3%, 0.35%, or 0.4%. In this invention, the initiator is preferably added in two batches, preferably with equal masses in both batches.

[0041] In this invention, the solvent in the reaction raw material liquid of the polymerization reaction preferably includes one or more of ethyl acetate (EA), butanone, or methyl isobutyl ketone (MIBK); the mass ratio of the solvent to the POSS cage-like polysilsesquioxane hydrophobic modifier is preferably 0.8~1.2:1, more preferably 1:1.

[0042] In this invention, the temperature of the free radical addition reaction is preferably 70~80℃, specifically preferably 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃ or 80℃; the time is preferably 2~4h, more preferably 3h.

[0043] In this invention, the preferred steps for mixing the blocked isocyanate, long-chain alkyl acrylate, POSS cage-like polysilsesquioxane hydrophobic modifier, chain transfer agent, initiator, and solvent to carry out a free radical addition reaction are as follows: Blocked isocyanate, long-chain alkyl acrylate, POSS cage-like polysilsesquioxane hydrophobic modifier, chain transfer agent, part of the initiator and solvent are first mixed and subjected to a first free radical addition reaction; after the first free radical addition reaction is completed, the remaining initiator is added to the obtained first free radical addition reaction solution to carry out a second free radical addition reaction.

[0044] In this invention, the temperatures of the first free radical addition reaction and the second free radical addition reaction are preferably the same as the temperature of the first free radical addition reaction described in the above technical solution, and will not be repeated here; the time of the first free radical addition reaction is preferably 2-4 hours, more preferably 3 hours; the time of the second free radical addition reaction is preferably 2-4 hours, more preferably 3 hours.

[0045] After the free radical addition reaction is completed, the present invention preferably obtains the hydrophobically modified blocked isocyanate directly without any further processing. In the present invention, the hydrophobically modified blocked isocyanate is preferably a solvent-containing hydrophobically modified blocked isocyanate.

[0046] After obtaining the hydrophobically modified blocked isocyanate, the present invention mixes the hydrophobically modified blocked isocyanate, emulsifier, pH adjuster, water and cosolvent, and performs high-pressure homogenization to obtain the waterborne blocked isocyanate curing agent.

[0047] In this invention, the emulsifier preferably comprises one or more of nonionic and cationic emulsifiers. In this invention, the nonionic emulsifier preferably comprises isotridecyl alcohol polyoxyethylene ether (1310) and / or castor oil polyoxyethylene ether (EL-40). In this invention, the cationic emulsifier preferably comprises one or more of ammonium chloride containing aliphatic segments, aliphatic tertiary amines, and amide emulsifiers. In this invention, the ammonium chloride containing aliphatic segments preferably comprises one or more of dicocarbamate and octadecylstearyl ammonium chloride. In this invention, the dicocarbamate preferably comprises dicocarbamate dimethyl ammonium chloride. In this invention, the octadecylstearyl ammonium chloride preferably comprises octadecyl dimethyl ammonium chloride. In one specific embodiment of this invention, the emulsifier preferably comprises dicocarbamate dimethyl ammonium chloride, castor oil polyoxyethylene ether, and isotridecyl alcohol polyoxyethylene ether, wherein the mass ratio of dicocarbamate dimethyl ammonium chloride, castor oil polyoxyethylene ether, and isotridecyl alcohol polyoxyethylene ether is preferably 1:1:1. In this invention, the mass ratio of the polyisocyanate to the emulsifier is preferably 10~20:2~5, more preferably 3~9:1, and specifically preferably 50:15 (3.33:1), 120:15 (8:1) or 72:15 (4.8:1).

[0048] In this invention, the pH adjuster preferably comprises an acid, which preferably comprises an organic acid, and the organic acid preferably comprises acetic acid. This invention does not specifically limit the amount of the pH adjuster used, as long as the pH of the high-pressure homogenized system is maintained at 3-6.

[0049] In this invention, the co-solvent preferably includes one or more of dipropylene glycol, tripropylene glycol, ethylene glycol butyl ether, diethylene glycol butyl ether, dipropylene glycol butyl ether, and dipropylene glycol methyl ether. In this invention, the mass ratio of the polyisocyanate to the co-solvent is preferably 10-20:5-10, more preferably 1-3:1, and specifically preferably 50:50 (1:1), 120:50 (2.4:1), or 72:50 (1.44:1).

[0050] In this invention, the water is preferably deionized water. In this invention, the mass ratio of the polyisocyanate to water is preferably 10~20:50~75, more preferably 1:2.5~8, and specifically preferably 50:355 (1:7.1), 120:355 (1:2.96), or 72:355 (1:4.93).

[0051] In this invention, the pressure of the high-pressure homogenization is preferably 20-50 MPa, more preferably 30 MPa; the pH value of the system for high-pressure homogenization is preferably 3-6, specifically preferably 3, 3.5, 4, 4.5, 5, 5.5, or 6; the number of high-pressure homogenization cycles is 3-5 times, more preferably 4 times. In this invention, the high-pressure homogenization is preferably carried out in a high-pressure homogenizer.

[0052] In this invention, the high-pressure homogenization can achieve a better emulsification effect, which is beneficial to obtaining a stable water-based closed isocyanate curing agent.

[0053] After high-pressure homogenization, the present invention preferably further includes solvent removal, preferably by rotary evaporation, and the rotary distillation temperature is preferably 50-65°C. In the present invention, the rotary evaporation is preferably performed on a rotary evaporator. In the present invention, the solvent removal process is mainly for removing the solvent.

[0054] In this invention, the solid content of the water-based blocked isocyanate curing agent is preferably 20-30%, more preferably 26%. In this invention, the pH value of the water-based blocked isocyanate curing agent is preferably 3-6, specifically preferably 3, 3.5, 4, 4.5, 5, 5.5, or 6.

[0055] The preparation method provided by the present invention involves polymerizing and capping polyisocyanate, blocking agent and hydroxy acrylate, followed by free radical addition reaction with cage-like polysilsesquioxane hydrophobic modifier to obtain hydrophobic modified blocked isocyanate, which is then emulsified with deionized water, emulsifier and cosolvent in a high-pressure homogenizer, and then desolventized to obtain waterborne blocked isocyanate curing agent.

[0056] The present invention also provides an aqueous blocked isocyanate curing agent prepared by the preparation method described above, wherein the solid content of the aqueous blocked isocyanate curing agent is 20-30%.

[0057] The water-based closed isocyanate curing agent provided by this invention has both high hydrophobicity and washability, and good stability; it can be used as a fabric waterproofing enhancer to improve the waterproofing effect of fabric waterproofing agents, while also improving the washability of fabric waterproofing agents, and has good washability whether dried or air-dried.

[0058] This invention also provides the application of the water-based closed-type isocyanate curing agent described in the above-mentioned technical solution in the waterproof finishing of fabrics. In this invention, the fabric material preferably includes one or more blended fabrics of cotton, nylon, and polyester. In this invention, the polyester preferably includes spring spun, imitation memory, or 290T. In a specific embodiment of this invention, the fabric material is preferably cotton, nylon, cotton-polyester blend, or polyester. In this invention, when the water-based closed-type isocyanate curing agent is applied in the waterproof finishing of fabrics, it is preferably used as a waterproofing synergist.

[0059] The present invention also provides a fabric waterproofing finishing agent, comprising a waterproofing agent and a synergist; The synergist is the water-based closed-type isocyanate curing agent described in the above technical solution.

[0060] The fabric waterproofing agent provided by this invention includes a waterproofing agent, which is preferably a fluorine-free waterproofing agent, and more preferably ECO-BARRIER purchased from Foco New Materials (Shanghai) Co., Ltd. @ X-9A or Eco-Barrier @ 702MA. In a specific embodiment of the present invention, the concentration of the waterproofing agent in the fabric waterproofing finishing agent is preferably 40 g / L.

[0061] The fabric waterproofing finishing agent provided by this invention includes a synergist, which is the water-based closed-type isocyanate curing agent described in the above-mentioned technical solution. In this invention, the mass concentration of the synergist in the fabric waterproofing finishing agent is preferably 1 / 3 to 1 / 5 of the mass concentration of the waterproofing agent, and more preferably 1 / 4.

[0062] The fabric waterproofing agent provided by the present invention preferably further includes a solvent, wherein the solvent is preferably water. In the present invention, the water is preferably deionized water.

[0063] The following detailed description, in conjunction with embodiments, illustrates the water-based closed-type isocyanate curing agent provided by the present invention, its preparation method, and its application in waterproof finishing of fabrics. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0064] All materials used in the examples are commercially available or prepared using conventional methods. Unless otherwise specified, the types of raw materials used in the examples are shown in Table 1.

[0065] Table 1 Types of Raw Materials

[0066] The raw materials for the waterproofing agent used in conjunction with this are as follows: ECO-BARRIER @ X-9A: Fluorine-free waterproofing agent from Fuco New Materials (Shanghai) Co., Ltd. ECO-BARRIER @ 702MA: Fluorine-free waterproofing agent from Fuco New Materials (Shanghai) Co., Ltd.

[0067] Performance testing (1) Waterproof rating test To verify the waterproofing effect of textiles treated with the fluorine-free waterproofing agent described in this invention, a standard method can be used for comparison. The standard method uses the national standard GB 4745—1997 to examine the waterproofing effect, and the specific process is as follows: Cut a 22×18cm sample, clamp it firmly, and install it on a fixed base at a 45° angle to the horizontal. Quickly and steadily pour 250mL (20±2℃) distilled or deionized water into the funnel, and spray it evenly and continuously towards the center of the sample through a nozzle at a distance from the center of the sample for 25~30s. After spraying, quickly remove the clamp, turn the sample face down to a horizontal position, gently tap it twice, observe the degree of wettability of the sample, and then evaluate its grade by describing it in words and comparing it with pictures.

[0068] The rating criteria are as follows: Level 1 / 50 – The entire surface to be sprayed is wetted.

[0069] Level 2 / 70 – Half of the surface being wetted, meaning the total wetted area is approximately half of the total surface area.

[0070] Level 3 / 80 - Only a small area of ​​the surface being wetted is intermittent.

[0071] Level 4 / 90 - The surface being sprayed is not wetted, but small water droplets are present.

[0072] Level 5 / 100 - The surface being sprayed is not wetted and there are no small water droplets.

[0073] (2) Washability test The washing method shall be carried out in accordance with GB / T-8629, consisting of 5 washes followed by drying and air drying.

[0074] Example 1 In a three-necked flask equipped with a stirrer, thermocouple, and reflux apparatus, 50 g of polyisocyanate (PAPI) and 8 g of hydroxy acrylate (HEA) were added to 100 g of solvent (MIBK) and reacted at 60 °C for 1 hour. Then, approximately 27 g of blocking agent (MEKO) was added dropwise at a rate of 200 g / h. After the MEKO addition was complete, the reaction was continued at 60 °C for 1 hour to obtain HEA-modified blocked isocyanate.

[0075] Add 50g of POSS cage-like polysilsesquioxane hydrophobic modifier POSS301, 20g of long-chain alkyl acrylate octadecyl acrylate, 50g of solvent ethyl acetate, and 0.2g of dodecyl mercaptan to the above three-necked flask, then add 0.15g of azobisisobutyronitrile and keep warm at 78℃ for 3h. Then add another 0.15g of azobisisobutyronitrile and keep warm at 78℃ for 3h to obtain solvent-containing POSS-modified blocked isocyanate.

[0076] The above-mentioned solvent-containing POSS modified blocked isocyanate was mixed with 355g of deionized water, emulsifier (5g of dicoalkyl dimethyl ammonium chloride, approximately 5g of EL-40, approximately 5g of 1310), co-solvent 50g of dipropylene glycol, and 3g of acetic acid to make the pH of the system 4.5. Then, the mixture was homogenized four times under a high-pressure homogenizer at 30MPa. The solvent was then removed to obtain an aqueous POSS301 modified blocked isocyanate with a solid content of approximately 26%.

[0077] Example 2 Same as in Example 1, replace 50 g of PAPI with 120 g of TDI-TMP adduct, and then obtain POSS301 modified waterborne blocked isocyanate with a solid content of 26% (adjust the amount of water according to the solid content).

[0078] Example 3 Same as in Example 1, 72 g of HDI trimer replaced 50 g of PAPI, and 30 g of 3,5-dimethylpyrazole replaced 27 g of MEKO, and then POSS301 modified waterborne blocked isocyanate with a solid content of 26% was obtained (the amount of water was adjusted according to the solid content).

[0079] Example 4 Same as in Example 1, but instead of POSS301, POSS302 was used to obtain POSS302 modified waterborne blocked isocyanate (the amount of water was adjusted according to the solid content).

[0080] Example 5 Same as in Example 1, but POSS301 was replaced with POSS306 to obtain POSS306 modified waterborne blocked isocyanate (the amount of water was adjusted according to the solid content).

[0081] Comparative Example 1 In a three-necked flask equipped with a stirrer, thermocouple, and reflux apparatus, 30 g of PAPI, 38 g of TDI-TMP adduct, and 80 g of MIBK were added. The temperature was then raised to 60 °C, and 22 g of methyl ethyl ketone oxime was added dropwise at 200 g / h for a capping reaction for 2 hours. After the capping reaction was completed, 6 g of N-methyldiethanolamine was added to the resulting capping reaction solution, and the temperature was raised to 70 °C for another 2 hours. The reaction ended when the NCO content was 0 as determined by the di-n-butylamine method.

[0082] The above-mentioned solvent-containing polymer was mixed with 220 g of deionized water, 4 g of emulsifier (specifically, approximately 2 g of EL-40 and 2 g of 1310), 25 g of dipropylene glycol as a co-solvent, and 4 g of acetic acid to adjust the pH of the system to 4.5. The mixture was homogenized four times at 25 MPa using a high-pressure homogenizer. The solvent was then removed to obtain a waterborne, blocked aromatic isocyanate with a solid content of approximately 26% without hydrophobic modification. Waterproof rating test ECO-BARRIER X-9A was mixed with water to form a 40 g / L waterproofing finishing solution. The blocked isocyanate emulsion described in the above examples was added to the finishing solution at a dosage of 10 g / L to form a fabric waterproofing finishing agent. The formulation of the fabric waterproofing finishing agent is shown in Table 2.

[0083] Table 2 Formulation of Waterproofing Agent for Fabrics

[0084] After the sample fabric was treated with the above-mentioned prepared waterproofing agent, it was dipped in a rolling mill and then treated in an oven at 170°C for about 70 seconds before the waterproofing level was tested. The results are shown in Figure 3.

[0085] Table 3. Waterproofing rating test results of fabrics treated with different waterproofing finishing agents.

[0086] Wash and dry resistance test The waterproofing agents for fabrics obtained from Application Examples 1 to 7 were tested. The fabrics treated with the waterproofing agents in Application Examples 1 to 7 were washed 10 times according to GB / T-8629 and then dried. The waterproofing performance after washing and drying was then tested, and the waterproofing performance is shown in Table 4.

[0087] Table 4. Wash and dry resistance of fabrics treated with different waterproofing finishing agents

[0088] Wash and dry test ECO-BARRIER 702MA was mixed with water to prepare a 40 g / L waterproofing finishing solution. The blocked isocyanate emulsion described in the above examples was added to the finishing solution at a dosage of 10 g / L to obtain a fabric waterproofing finishing agent. The formulation of the obtained fabric waterproofing finishing agent is shown in Table 5.

[0089] Table 5 Formulation of Waterproofing Agents for Fabrics

[0090] The fabric treated with the above-mentioned waterproofing agent was washed 5 times according to GB / T-8629, and then dried at room temperature of 20℃ and humidity of 65% for 24 hours. The waterproof performance after washing and drying was then tested, and the waterproof performance is shown in Table 6.

[0091] Table 6. Wash and dry resistance of fabrics treated with different waterproofing finishing agents

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an aqueous blocked isocyanate curing agent, characterized in that, Includes the following steps: Polyisocyanate, hydroxy acrylate and solvent are mixed and polymerized. A blocking agent is added to the resulting polymerization system to carry out an end-capping reaction, thereby obtaining a blocked isocyanate. The blocked isocyanate, long-chain alkyl acrylate, POSS cage-like polysilsesquioxane hydrophobic modifier, chain transfer agent, initiator and solvent are mixed and subjected to free radical addition reaction to obtain hydrophobically modified blocked isocyanate. The hydrophobically modified blocked isocyanate, emulsifier, pH adjuster, water and cosolvent are mixed and homogenized under high pressure to obtain the water-based blocked isocyanate curing agent. The polyisocyanate includes at least one of hexamethylene diisocyanate trimer, hexamethylene diisocyanate biuret, isophorone diisocyanate trimer, polymethylene polyphenyl isocyanate, and toluene diisocyanate-trimethylolpropane adduct; The mass ratio of the polyisocyanate to the hydroxy acrylate is 10~20:1~3; The mass ratio of the polyisocyanate to the blocking agent is 10~20:3~8; The mass ratio of the polyisocyanate to the long-chain alkyl acrylate is 10~20:1~5; The mass ratio of the polyisocyanate to the POSS cage-like polysilsesquioxane hydrophobic modifier is 10~20:5~10; The hydroxy acrylates include one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate; The long-chain alkyl acrylates include one or more of hexadecyl acrylate, octadecyl acrylate, hexadecyl methacrylate, and octadecyl methacrylate; The POSS cage-like polysilsesquioxane hydrophobic modifier is methacryloyloxypropyl heptaisobutyl cage-like polysilsesquioxane.

2. The preparation method according to claim 1, characterized in that, The polymerization reaction is carried out at a temperature of 40~80℃ for a time of 0.5~1.5h.

3. The preparation method according to claim 1, characterized in that, The blocking agent includes one or more of methyl ethyl ketone oxime, acetone oxime, diethyl malonate, and 3,5-dimethylpyrazole; The end-capping reaction is carried out at a temperature of 40~80℃ for a time of 0.5~1.5h.

4. The preparation method according to claim 1, characterized in that, The chain transfer agent comprises dodecyl mercaptan, and the added mass of the chain transfer agent is 0.05~0.3% of the total mass of the polyisocyanate, hydroxy acrylate, blocking agent, long-chain alkyl acrylate and POSS cage-like polysilsesquioxane hydrophobic modifier; The initiator includes azobisisobutyronitrile, and the mass of the initiator added is 0.1 to 0.4% of the total mass of the polyisocyanate, hydroxy acrylate, blocking agent, long-chain alkyl acrylate and POSS cage-like polysilsesquioxane hydrophobic modifier.

5. The preparation method according to claim 1 or 4, characterized in that, The free radical addition reaction is carried out at a temperature of 70-80°C for 2-4 hours.

6. The preparation method according to claim 1, characterized in that, The emulsifier includes a nonionic emulsifier or a cationic emulsifier. The nonionic emulsifier includes isomeric tridecyl alcohol polyoxyethylene ether and / or castor oil polyoxyethylene ether. The cationic emulsifier includes one or more of ammonium chloride containing aliphatic segments, aliphatic tertiary amines, and amide emulsifiers. The ammonium chloride containing aliphatic segments includes one or more of dicocoyl ammonium chloride and octadecyl stearyl ammonium chloride. The mass ratio of the polyisocyanate to the emulsifier is 10~20:2~5. The co-solvent includes one or more of dipropylene glycol, tripropylene glycol, ethylene glycol butyl ether, diethylene glycol butyl ether, dipropylene glycol butyl ether, and dipropylene glycol methyl ether; the mass ratio of the polyisocyanate to the co-solvent is 10~20:5~10; The pH adjuster includes an acid; The mass ratio of the polyisocyanate to water is 10~20:50~70.

7. The preparation method according to claim 1 or 6, characterized in that, The high-pressure homogenization is performed at a pressure of 20-50 MPa, with a system pH of 3-6, and the high-pressure homogenization is performed 3-5 times.

8. The aqueous blocked isocyanate curing agent prepared by the preparation method according to any one of claims 1 to 7, wherein the solid content of the aqueous blocked isocyanate curing agent is 20 to 30%.

9. The application of the water-based closed-type isocyanate curing agent according to claim 8 in waterproof finishing of fabrics.

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