Sulfonic acid type waterborne polyurethane compound with low water absorption rate, preparation method thereof, waterproof coating and application

Abstract

The invention discloses a sulfonic acid type waterborne polyurethane compound with low water absorption, a preparation method thereof, a waterproof coating and application. The sulfonic acid type waterborne polyurethane compound with low water absorption rate is prepared from the following raw materials: polyisocyanate, polyether polyol and / or monohydric alcohol, micromolecular dihydric alcohol, an amino compound, a sulfonate chain extender and a hydrophobic film-forming modifier. The waterproof coating prepared from the waterborne polyurethane compound does not contain VOCs, is lower in water absorption rate, higher in ductility, more excellent in comprehensive mechanical property and better in heat / acid / alkali resistance, is a green and environment-friendly macromolecular waterproof coating, and can be applied to waterproofing of outer walls, toilets, kitchens, basements and the like.

Description

Technical Field

[0001] The invention belongs to the field of waterproof coatings, and specifically relates to a sulfonic acid type waterborne polyurethane composite with low water absorption rate, and a preparation method and application thereof. Background Art

[0002] Waterproofing is crucial in the construction and engineering fields, especially in areas susceptible to water intrusion such as roofs, basements and bathrooms. Commonly used waterproofing materials include polymer-modified cement waterproofing coatings, elastomer waterproofing coatings, asphalt waterproofing materials, polyurethane waterproofing coatings and polymer waterproofing membranes. Among them, polyurethane waterproofing coatings are highly favored due to their excellent waterproofing effect, outstanding elasticity and toughness, excellent substrate adhesion and convenient construction.

[0003] At present, the polyurethane waterproof coatings on the market are still dominated by solvent-based polyurethane waterproof coatings, which can be divided into single-component and two-component polyurethane waterproof coatings. Among them, the single-component polyurethane waterproof coating is a mixture of terminal-NCO prepolymers with inorganic pigments / fillers, additives and solvents in a certain proportion. After construction, during the process of solvent evaporation and film formation, the isocyanate group of the prepolymer reacts with the substrate or moisture in the air to establish strength. Two-component polyurethane waterproof coatings establish strength and performance through the reaction of prepolymers with curing agents or latent curing agents. However, solvent-based polyurethane waterproof coatings have serious disadvantages. When used, they will emit higher levels of volatile organic compounds (VOCs) into the environment, seriously endangering the health of construction workers and users, and causing environmental pollution.

[0004] CN104194610B discloses a self-crosslinking one-component polyurethane waterproof coating, which introduces a diacetone acrylamide structure into the molecular chain through a modifier with a special structure, and realizes self-crosslinking through ketone hydrazine crosslinking. The water-based polyurethane waterproof coating has no NCO residue and is non-toxic and environmentally friendly. However, the waterproof coating has insufficient water resistance and is far behind oily polyurethane.

[0005] CN105622878B discloses a silicon-fluorine modified waterborne polyurethane waterproof coating, which improves the hydrophobic effect by introducing silicon and fluorine elements into the polyurethane molecular chain. However, the water absorption rate of the coating film exceeds 7.1% after being immersed in water for 24 hours, which is far from the standard of water absorption rate less than 5% after immersion in water for 7 days. It does not have a good waterproof effect. In addition, the raw material cost is high and the industrial value is not great.

[0006] CN115710455B discloses a sulfonate-type waterborne polyurethane waterproof coating, which is prepared by using a self-modified sulfonic acid-type hydrophilic chain extender to prepare a waterborne polyurethane waterproof coating with good controllability and good emulsion stability. However, the water absorption rate of the waterproof coating is still relatively high, and the elongation and tensile strength are insufficient.

[0007] Therefore, it is necessary to develop a new type of solvent-free polyurethane waterproof coating with performance close to that of solvent-based waterproof coating. Summary of the invention

[0008] In view of the above-mentioned deficiencies in the prior art, one of the purposes of the present invention is to provide a novel polyurethane waterproof coating and its application which is solvent-free and has performance close to that of solvent-based waterproof coating. Another purpose of the present invention is to provide a sulfonic acid-type waterborne polyurethane composite with low water absorption and its preparation method.

[0009] To achieve the above object, the present invention adopts the following technical solution:

[0010] A sulfonic acid type waterborne polyurethane composite with low water absorption is prepared from raw materials including the following components:

[0011] S1, one or more polyisocyanates;

[0012] S2, one or more polyether polyols and / or polyether monools, having an average molecular weight of 400-4500 g / mol, preferably 600-3000 g / mol, more preferably 2000 g / mol;

[0013] S3, one or more small molecule diols, as chain extenders, containing at least two groups that can react with isocyanate and having an average molecular weight of 60-499 g / mol;

[0014] S4, one or more amino compounds, i.e., polyamine small molecule chain extenders containing active hydrogen, having an average molecular weight of 60-499 g / mol;

[0015] S5, one or more sulfonate chain extenders, containing two groups reactive with isocyanate, having an average molecular weight of 100-700 g / mol;

[0016] S6, one or more hydrophobic film-forming modifiers, having an average molecular weight of 150-3000 g / mol, preferably an average molecular weight of 250-1500 g / mol; and a water absorption rate of preferably ≤5%, more preferably ≤2%;

[0017] S7, water;

[0018] S8, an optional catalyst capable of catalyzing the reaction of isocyanate groups with hydroxyl groups;

[0019] S9. An organic solvent which does not contain a group capable of reacting with isocyanate.

[0020] In the present invention, in the above-mentioned sulfonic acid type waterborne polyurethane composite with low water absorption rate,

[0021] Based on the total mass of components S1-S6:

[0022] The amount of component S1 is 15.5-24.5wt%, preferably 17-22wt%;

[0023] The amount of component S2 is 50-65wt%, preferably 55-60wt%;

[0024] The amount of component S3 is 1.0-6.0wt%, preferably 2.3-4.8wt%;

[0025] The amount of component S4 is 0.1-2.5wt%, preferably 0.6-1.6wt%;

[0026] The amount of component S5 is 1.0-7.0wt%, preferably 1.6-5.0wt%;

[0027] The amount of component S6 is 2-25wt%, preferably 12-20wt%;

[0028] Based on the total mass of components S1-S3:

[0029] The dosage of component S8 is 0-2000ppm, preferably 100-500ppm;

[0030] The dosage of component S9 is 0.7-3.0 times, preferably 1.0-2.2 times.

[0031] In the present invention, in the component S1 of the above-mentioned sulfonic acid type waterborne polyurethane composite with low water absorption, the polyisocyanate includes but is not limited to one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexyl diisocyanate, 1,5-naphthalene diisocyanate, p-phenylenediisocyanate, p-phenylenediisocyanate, 2,4-ethylphenyl diisocyanate, methylcyclohexyl diisocyanate, and isopropyl dicyclohexyl isocyanate; more preferably, one or more of toluene diisocyanate and dicyclohexylmethane diisocyanate.

[0032] In the present invention, in component S2 of the above-mentioned sulfonic acid type waterborne polyurethane composite with low water absorption, the polyether polyol and / or polyether monool include but are not limited to one or more of polyether monool and polyether diol; preferably, the polyether polyol and / or polyether monool described in component S2 is a mixture of polyether monool and polyether diol; more preferably, the content of polyether monool in the mixture is 0.4-2.0% based on the total weight, and the content of polyether diol is 98.0-99.6%;

[0033] Preferably, the polyether monool is a monohydroxy polyoxyethylene ether, and its number average molecular weight is preferably 350-3000 g / mol, more preferably 520-2200 g / mol;

[0034] Preferably, the polyether diol is one or both of polypropylene glycol and polybutylene glycol; the number average molecular weight of the polyether diol is preferably 400-4000 g / mol, more preferably 650-3000 g / mol, such as DL-2000D and DL-3000D of Bluestar Dongda, and DL-4000D of Wanhua Chemical. 2010D, 2030, BASF’s PTMEG-1000, PTMG-2000.

[0035] In the present invention, in component S3 of the above-mentioned sulfonic acid type waterborne polyurethane composite with low water absorption, the small molecule diol includes but is not limited to one or more of ethylene glycol, diethylene glycol, 1,2-propylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol and neopentyl glycol; preferably one or more of neopentyl glycol, 1,4-butanediol and 1,4-cyclohexanedimethanol.

[0036] In the present invention, in component S4 of the above-mentioned sulfonic acid type waterborne polyurethane composite with low water absorption, the amino compound is selected from one or more of aromatic, aliphatic and alicyclic polyamines, including but not limited to 4,4'-diaminodiphenylmethane, ethylenediamine, 2-methylpentanediamine, N-hydroxyethylethylenediamine, isophoronediamine, 1,6-hexanediamine, 4,4'-diaminodicyclohexylmethane, 1,4-diaminocyclohexane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. A mixture of two or more of these; more preferably, a mixture of two or three of the following: ethylenediamine, hydroxyethylethylenediamine, 4,4'-diaminodicyclohexylmethane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0037] In the present invention, in component S5 of the above-mentioned sulfonic acid type waterborne polyurethane composite with low water absorption, the sulfonate chain extender includes but is not limited to one or more of small molecule sulfonic acid type diol (S5-1) and small molecule sulfonic acid type diamine (S5-2); the number average molecular weight of the sulfonate chain extender is preferably 100-700 g / mol, more preferably 190-550 g / mol, such as Taiwan Double Bond's sulfonic acid diol PO204, Wanhua's 2-[(2-aminoethyl)amino]ethanesulfonic acid sodium salt, and Ruierfeng's 2-[(2-aminoethyl)amino]propanesulfonic acid sodium salt.

[0038] In the present invention, in the component S6 of the sulfonic acid type waterborne polyurethane composite with low water absorption, the hydrophobic film-forming modifier is selected from one or more of epoxy resin ring-opening adducts, chlorinated derivatives of paraffin, and polyether polyurethane oligomers, and the number average molecular weight thereof is preferably 150-3000 g / mol, more preferably 250-1500 g / mol;

[0039] Preferably, the epoxy resin ring-opening adduct is a ring-opening adduct of an epoxy resin and a monohydric alkyl alcohol, wherein the number of carbon atoms of the monohydric alkyl alcohol is 4-30;

[0040] Preferably, the chlorinated derivative of paraffin is a chlorinated derivative of C8-C26 paraffin, and the chlorination rate is 40-70% of the total weight;

[0041] Preferably, the polyether polyurethane oligomer is an addition product of polyisocyanate, polyether diol and monohydric alkyl alcohol.

[0042] In the present invention, the solid content of the sulfonic acid type waterborne polyurethane composite with low water absorption is preferably 40-65wt%, more preferably 45-55wt%; the average particle size of the solid content is preferably in the range of 150-650nm, more preferably in the range of 200-400nm.

[0043] In another aspect of the present invention, a method for preparing the sulfonic acid type waterborne polyurethane composite with low water absorption is provided, comprising the following steps:

[0044] 1) Component S1, component S2, component S3, component S8, part of component S9 and optional component S5-1 are mixed and reacted at 65-85° C. until NCO reaches a theoretical value to form a diisocyanate-terminated prepolymer;

[0045] 2) cooling the prepolymer obtained in step 1) to 25-55° C., adding component S6 and the remaining component S9, and stirring and mixing them uniformly;

[0046] 3) adding component S4 and optional component S5-2 to the prepolymer dilution obtained in step 2), and reacting at 25-55° C. for 5-25 min;

[0047] 4) adding component S7 to the polyurethane solution obtained in step 3) under high-speed stirring to obtain a crude emulsion, and removing the solvent to obtain a sulfonic acid-type waterborne polyurethane composite with low water absorption;

[0048] Among them, at least one of component S5-1 and component S5-2 is added.

[0049] Preferably, in step 1) and step 2), the mass ratio of component S9 added is 1 / (6-15), for example, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, etc.;

[0050] Preferably, in step 3), the component S4 and the optional component S5-2 are added in the form of an aqueous solution or an acetone solution, and the amount of water or acetone used is 1-20 times the total mass of the component S4 and the component S5-2, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 times, etc.

[0051] The present invention also provides a waterborne polyurethane waterproof coating, which comprises the aforementioned sulfonic acid type waterborne polyurethane composite with low water absorption.

[0052] In a specific embodiment, the waterborne polyurethane waterproof coating contains one or more of a pigment / filler, a dispersant, a defoamer, a film-forming aid, a stabilizer, a wetting agent, and a thickener in addition to the aforementioned sulfonic acid-type waterborne polyurethane complex with low water absorption.

[0053] The present invention also provides an application of a water-based polyurethane waterproof coating in the field of building waterproofing, which is particularly suitable for waterproofing of roofs, exterior walls, toilets, kitchens, basements, etc.

[0054] The beneficial effects of the present invention are mainly reflected in the following aspects:

[0055] (1) The present invention is different from the general sulfonic acid type water-based polyurethane emulsion. It adopts a core-shell structure design concept, with a hydrophobic film-forming modifier as the core and a hydrophilic polyurethane as the shell. The hydrophobic film-forming modifier has a relatively small molecular weight and can fill the gaps existing when the latex particles are fused, thereby improving the film-forming property of the emulsion, enhancing the density of the coating, and greatly reducing the water absorption rate of the coating. At the same time, the comprehensive mechanical properties of the paint film are also improved to a certain extent.

[0056] (2) The present invention is different from general water-based polyurethane waterproof coatings. The water-based polyurethane waterproof coating prepared using the sulfonic acid type water-based polyurethane composite has lower water absorption, better comprehensive mechanical properties, and better heat / acid / alkali resistance. DETAILED DESCRIPTION

[0057] The following examples are further explanations of the present invention, rather than limiting the scope of the present invention. It should be understood by those skilled in the art that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should all be included in the scope of the claims of the present invention. Within the scope of the present invention, the above-mentioned various technical features of the present invention and the various technical features specifically described below (such as in the examples) can be combined with each other to form a new or preferred technical solution.

[0058] 1. Main raw material sources of embodiments:

[0059] Polytetramethylene glycol: industrial grade, molecular weight 2000 g / mol, BASF;

[0060] Polypropylene glycol: industrial grade, molecular weight 2000 g / mol, Wanhua Chemical Group Co., Ltd.

[0061] Catalyst: Bi@8108, industrial grade, Leading Co., Ltd., USA;

[0062] Neopentyl glycol: industrial grade, Wanhua Chemical Group Co., Ltd.;

[0063] 1,4-Cyclohexanedimethanol, technical grade, Alfa Aesar Chemicals Ltd.;

[0064] 1,4-Butanediol: industrial grade, Wanhua Chemical Group Co., Ltd.;

[0065] Acetone: industrial grade, Wanhua Chemical Group Co., Ltd.;

[0066] 4,4-Dicyclohexylmethane diisocyanate: industrial grade, Wanhua Chemical Group Co., Ltd.;

[0067] Isophorone diisocyanate: industrial grade, Wanhua Chemical Group Co., Ltd.

[0068] Toluene diisocyanate: industrial grade, Wanhua Chemical Group Co., Ltd.;

[0069] Ethylenediamine: analytical grade, Sinopharm Chemical Reagent Co., Ltd.;

[0070] 4,4'-Diaminodicyclohexylmethane: industrial grade, Wanhua Chemical Group Co., Ltd.;

[0071] N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane: industrial grade, Yunsheng Chemical Co., Ltd.;

[0072] Small molecule sulfonic acid diamine A95: industrial grade, Wanhua Chemical Group Co., Ltd.

[0073] Small molecule sulfonic acid diol PO204: industrial grade, Double Bond Chemical Co., Ltd., Taiwan, China;

[0074] Polyethylene glycol monomethyl ether: industrial grade, molecular weight 1200 g / mol, Hannong Chemical Co., Ltd.

[0075] 42#-Chlorinated derivatives of medium-chain paraffins: industrial grade, Donghong Environmental Protection Materials Technology Co., Ltd.;

[0076] Epoxy resin E44: industrial grade, Sinopec;

[0077] PPG-600: industrial grade, Wanhua Chemical Group Co., Ltd.

[0078] Guerbet alcohol 16: technical grade, Sasol Chemical;

[0079] Guerbet alcohol XII: technical grade, Sasol Chemical;

[0080] Boron trifluoride ethyl ether: analytical grade, Sinopharm Group.

[0081] 2. Analytical instruments and test methods:

[0082] All tests were conducted under standard test conditions: temperature 23±2℃, relative humidity 50±10%. The final coating thickness is required to be controlled at 1.5±0.2mm. The prepared coating needs to be demoulded after curing for 96 hours under standard test conditions, and then turned over and cured in a 40±2℃ electric heating blast drying oven for 48 hours. After taking it out, it should be placed under standard test conditions for 4 hours.

[0083] Solid content test: Test according to Chapter 5 of GB / T16777-2008;

[0084] Particle size test method: Malvern particle size analyzer;

[0085] Water absorption: Test according to 6.15 of GB / T19250-2013;

[0086] Tensile properties: Tested in accordance with 6.9 of GB / T 19250-2013;

[0087] Alkali treatment: According to 9.2.3 water-based coating test method in GB / T16777-2008;

[0088] Acid treatment: According to 9.2.4 water-based coating test method in GB / T16777-2008.

[0089] 1) Preparation of epoxy resin ring-opening adducts:

[0090] 227.3 g of epoxy resin E44 and 242.5 g of Guerbet alcohol hexadecene were heated to 65° C. and stirred to mix evenly; then 4.70 g of boron trifluoride etherate was added and the mixture was kept warm for 6 hours to obtain epoxy resin ring-opening adduct EPA.

[0091] 2) Preparation of polyether polyurethane oligomers:

[0092] 174.9 g HMDI, 200 g PPG600 and 0.1 g Bi@8108 were heated to 75° C. and reacted for 1.5 h, and then 124.3 g Guerbet alcohol dodecahydrate was added and the reaction was continued at the temperature for 1.5 h to obtain polyether polyurethane oligomer PUO.

[0093] 3) Preparation of waterborne polyurethane composites

[0094] Example 1

[0095] Heat 280.00g DL-2000D, 3.20g MPEG1200 and 13.62g NPG to 60℃ and stir to mix well, then add 104.80g HMDI, and finally 44.22g acetone and 0.12g Bi@8108 catalyst were added, and the temperature was raised to 75°C and reacted for 4h to generate a prepolymer containing an isocyanate group at the end.

[0096] The temperature was lowered to below 50°C, 78.87g of epoxy resin ring-opening adduct EPA and 530.72g of acetone were added to the prepolymer, and after uniform mixing, 6.52g of hydroxyethylethylenediamine and 9.18g of A95 (diluted with 47.10g of water) were added in a metered manner, and the reaction was continued at 45°C for 10min, and then 1.33g of KH-792 (diluted with 13.30g of acetone) was added and the reaction was continued for 15min.

[0097] 445.83 g of deionized water was added under shear dispersion conditions with the speed of the disperser adjusted to 1200-1500 r / min, and stirring was continued for 25 minutes. Finally, acetone was removed by vacuum distillation to obtain an aqueous polyurethane dispersion with a solid content of 50% and a particle size of 269 nm.

[0098] Example 2

[0099] Heat 292.00g DL-2000D, 4.18g MPEG1200 and 23.35g 1,4-cyclohexanedimethanol to 60°C and stir to mix well, then add 54.22g HMDI and 36.00g TDI-80, and finally 39.09g acetone and 0.07g Bi@8108 catalyst were added, and the temperature was raised to 75°C and reacted for 4h to generate a prepolymer containing an isocyanate group at the end.

[0100] The temperature was lowered to below 50°C, 100.73 g of a chlorinated derivative of 4,2-medium chain paraffin and 469.14 g of acetone were added to the prepolymer, and after uniform mixing, 2.08 g of ethylenediamine and 9.68 g of A95 (diluted with 35.27 g of water) were metered in, and the reaction was continued at 45°C for 10 min, and then 1.67 g of KH-792 (diluted with 16.70 g of acetone) was added and the reaction was continued for 15 min.

[0101] 483.80 g of deionized water was added under shear dispersion conditions with the speed of the disperser adjusted to 1200-1500 r / min, and stirring was continued for 25 minutes. Finally, acetone was removed by vacuum distillation to obtain an aqueous polyurethane dispersion with a solid content of 50% and a particle size of 348 nm.

[0102] Example 3

[0103] Heat 280.00g PTMEG2000, 4.20g MPEG1200, 22g PO204 and 11.79g 1,4-butanediol to 60°C and stir to mix well, then add 104.80g HMDI, and finally 50g acetone and 0.07g Bi@8108 catalyst were added, and the temperature was raised to 75°C and reacted for 6h to generate a prepolymer containing an isocyanate group at the end.

[0104] The temperature was lowered to below 50°C, 58.23 g of polyether polyurethane oligomer PUO and 530.72 g of acetone were added to the prepolymer, and after uniform mixing, 2.44 g of ethylenediamine and 1.21 g of 4,4'-diaminodicyclohexylmethane (diluted with 68.4 g of acetone) were added, and the reaction was continued at 45°C for 10 min, and then 1.12 g of KH-792 (diluted with 13.30 g of acetone) was added and the reaction was continued for 10 min.

[0105] 485.22 g of deionized water was added under shear dispersion conditions with the speed of the disperser adjusted to 1200-1500 r / min, and stirring was continued for 25 minutes. Finally, acetone was removed by vacuum distillation to obtain an aqueous polyurethane dispersion with a solid content of 50% and a particle size of 297 nm.

[0106] Comparative Example 1

[0107] Heat 292.00g DL-2000D, 4.18g MPEG1200 and 23.35g 1,4-cyclohexanedimethanol to 60°C and stir to mix well, then add 54.22g HMDI and 36.00g TDI-80, and finally 39.09g acetone and 0.07g Bi@8108 catalyst were added, and the temperature was raised to 75°C and reacted for 4h to generate a prepolymer containing an isocyanate group at the end.

[0108] The temperature was lowered to below 50°C, 469.14 g of acetone was added to the prepolymer, and after uniform mixing, 2.08 g of ethylenediamine and 9.68 g of A95 (diluted with 35.27 g of water) were added, and the reaction was continued at 45°C for 10 min, and then 1.67 g of KH-792 (diluted with 16.70 g of acetone) was added and the reaction was continued for 15 min.

[0109] 435.41 g of deionized water (ensuring that the solid content is equivalent to that in Example 2) was added under shear dispersion conditions with the speed of the disperser adjusted to 1200-1500 r / min, and stirring was continued for 25 min. Finally, acetone was removed by vacuum distillation to obtain an aqueous polyurethane dispersion with a solid content of 50% and a particle size of 277 nm.

[0110] Comparative Example 2

[0111] Heat 320.00g DL-2000D, 4.20g MPEG1200, 11.36g neopentyl glycol and 5.46g 2,2-dimethylol propionic acid to 60°C and stir to mix well, then add 93.39g IPDI, and finally 43.45g acetone and 0.18g Bi@8108 catalyst were added, and the temperature was raised to 75°C and reacted for 6h to generate a prepolymer containing an isocyanate group at the end.

[0112] The temperature was lowered to below 40°C, 105.35 g of chlorinated derivative of 4,2-medium chain paraffin and 347.67 g of acetone were added to the prepolymer, mixed evenly, 3.50 g of triethylamine was added for neutralization for 10 min, and then 1.22 g of KH-792 (diluted with 12.2 g of acetone) was added for chain extension for 5 min.

[0113] 511.28 g of deionized water was added under shear dispersion conditions with the speed of the disperser adjusted to 1200-1500 r / min, followed by 1.97 g of ethylenediamine and 5.50 g of isophoronediamine (diluted with 37.35 g of water), and stirring was continued for 25 min. Finally, acetone was removed by vacuum distillation to obtain an aqueous polyurethane dispersion with a solid content of 50% and a particle size of 485 nm.

[0114] Comparative Example 3

[0115] Heat 320.00g DL-2000D, 4.20g MPEG1200, 7.37g neopentyl glycol and 10.6g 2,2-dimethylol propionic acid to 60°C and stir to mix well, then add 93.39g IPDI, and finally 43.56g acetone and 0.18g Bi@8108 catalyst were added, and the temperature was raised to 75°C and reacted for 6h to generate a prepolymer containing an isocyanate group at the end.

[0116] The temperature was lowered to below 40°C, 105.35 g of chlorinated derivative of 4,2-medium chain paraffin and 348.59 g of acetone were added to the prepolymer, mixed evenly, 6.79 g of triethylamine was added for neutralization for 10 min, and then 1.22 g of KH-792 (diluted with 12.2 g of acetone) was added for chain extension for 5 min.

[0117] 512.25 g of deionized water was added under shear dispersion conditions with the speed of the disperser adjusted to 1200-1500 r / min, followed by 1.97 g of ethylenediamine and 5.50 g of isophoronediamine (diluted with 37.35 g of water), and stirring was continued for 25 min. Finally, acetone was removed by vacuum distillation to obtain an aqueous polyurethane dispersion with a solid content of 50% and a particle size of 287 nm.

[0118] The mass fraction of sodium sulfonate in Examples 1-3 is 0.50-0.86% of the resin, and the mass fraction of carboxylate converted to sodium sulfonate in Comparative Example 2 is 0.77%, which is basically consistent with the examples, but the emulsion stability is biased and the emulsion breaks during pulping. Therefore, the carboxylate content in Comparative Example 3 is increased to ensure the emulsion stability. The mass fraction of carboxylate converted to sodium sulfonate in Comparative Example 3 is 1.48% of the resin.

[0119] Preparation of waterborne polyurethane waterproof coating:

[0120] After the stabilizer is added to the water and dispersed evenly, the dispersant, wetting agent, defoaming agent and film-forming aid are added, and the mixture is stirred at a speed of 100-300 rpm to make the above materials evenly dispersed in the water; then the filler is added in two batches and dispersed evenly, and the aqueous polyurethane dispersions prepared in the embodiment and the comparative example are respectively added, stirred until the dispersion and the slurry are evenly mixed, and then a thickener is added to adjust the viscosity to 2000-6000 cP, and a water-based polyurethane waterproof coating can be obtained.

[0121] 45 parts of aqueous polyurethane dispersion; 42 parts of filler (precipitated barium sulfate); 1.5 parts of dispersant (731A); 0.8 parts of defoamer (A10); 0.5 parts of film-forming aid (Texanol); 0.1 parts of stabilizer (cellulose HE-10K); 0.2 parts of wetting agent (BD109); 0.1 parts of thickener (U505); 9.8 parts of water.

[0122] Specific performance test data are shown in the following table:

[0123] surface 1 1 Mechanical properties and waterproof properties of waterborne polyurethane waterproof coating film

[0124]

[0125] The retention rate of tensile strength of the above-mentioned cured coating after heat / acid / alkaline treatment is 100% to 120%, and the elongation at break is not less than 750%. The specific results are shown in Table 2.

[0126] surface 2 2 Mechanical properties of waterborne polyurethane waterproof coating film after heat / acid / alkali treatment

[0127]

[0128] Note: The paint film of comparative example 3 had blistering problem on the surface after alkali treatment;

[0129] It can be seen from Table 1 and Table 2 that the water-based polyurethane waterproof coating prepared using the sulfonic acid-type water-based polyurethane composite in Examples 1-3 has lower water absorption and greater elongation, and the overall performance of the coating film after heat / acid / alkali treatment is maintained well, and the industrial value is high.

Claims

1. A sulfonic acid type waterborne polyurethane composite with low water absorption, characterized in that: It is prepared from raw materials including the following components: S1, polyisocyanate; S2, polyether polyol and / or polyether monool, having an average molecular weight of 400-4500 g / mol, preferably 600-3000 g / mol, more preferably 2000 g / mol; S3, a small molecule diol containing at least two groups that can react with isocyanate and having an average molecular weight of 60-499 g / mol; S4, an amino compound having an average molecular weight of 60-499 g / mol; S5, a sulfonate chain extender, containing two groups capable of reacting with isocyanate and having an average molecular weight of 100-700 g / mol; S6, a hydrophobic film-forming modifier having an average molecular weight of 150-3000 g / mol, preferably an average molecular weight of 250-1500 g / mol; its water absorption rate is preferably ≤5%, more preferably ≤2%; S7, water; S8, an optional catalyst capable of catalyzing the reaction of isocyanate groups with hydroxyl groups; S9. An organic solvent which does not contain a group capable of reacting with isocyanate.

2. The sulfonic acid type waterborne polyurethane composite with low water absorption according to claim 1, characterized in that: Based on the total mass of components S1-S6: The amount of component S1 is 15.5-24.5wt%, preferably 17-22wt%; The amount of component S2 is 50-65wt%, preferably 55-60wt%; The amount of component S3 is 1.0-6.0wt%, preferably 2.3-4.8wt%; The amount of component S4 is 0.1-2.5wt%, preferably 0.6-1.6wt%; The amount of component S5 is 1.0-7.0wt%, preferably 1.6-5.0wt%; The amount of component S6 is 2-25wt%, preferably 12-20wt%; Based on the total mass of components S1-S3: The dosage of component S8 is 0-2000ppm, preferably 100-500ppm; The dosage of component S9 is 0.7-3.0 times, preferably 1.0-2.2 times.

3. The sulfonic acid type waterborne polyurethane composite with low water absorption according to claim 1 or 2, characterized in that: The polyisocyanate of component S1 is selected from one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexyl diisocyanate, 1,5-naphthalene diisocyanate, p-phenylenediisocyanate, p-phenylenediisocyanate, 2,4-ethylphenyl diisocyanate, methylcyclohexyl diisocyanate, and isopropylidene dicyclohexyl isocyanate; preferably one or more of toluene diisocyanate and dicyclohexylmethane diisocyanate; And / or, the component S2 is a mixture of polyether monool and polyether diol; preferably, the content of polyether monool in the mixture is 0.4-2.0%, and the content of polyether diol is 98.0-99.6% based on the total weight; Preferably, the polyether monool is a monohydroxy polyoxyethylene ether, and its number average molecular weight is preferably 350-3000 g / mol, more preferably 520-2200 g / mol; Preferably, the polyether diol is one or both of polypropylene glycol and polybutylene glycol; the number average molecular weight of the polyether diol is preferably 400-4000 g / mol, more preferably 650-3000 g / mol; And / or, the small molecule diol of component S3 is selected from one or more of ethylene glycol, diethylene glycol, 1,2-propylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol and neopentyl glycol; preferably one or more of neopentyl glycol, 1,4-butanediol and 1,4-cyclohexanedimethanol; And / or, the amino compound of component S4 is selected from one or more of aromatic, aliphatic, and alicyclic polyamines, preferably a mixture of two or more of 4,4'-diaminodiphenylmethane, ethylenediamine, 2-methylpentanediamine, N-hydroxyethylethylenediamine, isophoronediamine, 1,6-hexanediamine, 4,4'-diaminodicyclohexylmethane, 1,4-diaminocyclohexane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; more preferably a mixture of two or three of ethylenediamine, hydroxyethylethylenediamine, 4,4'-diaminodicyclohexylmethane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. And / or, the sulfonate chain extender of component S5 is selected from one or more of small molecule sulfonic acid diols (S5-1) and small molecule sulfonic acid diamines (S5-2); the number average molecular weight of the sulfonate chain extender is preferably 100-700 g / mol, more preferably 190-550 g / mol.

4. The sulfonic acid type waterborne polyurethane composite with low water absorption according to claim 1 or 2, characterized in that: The hydrophobic film-forming modifier of component S6 is selected from one or more of epoxy resin ring-opening adducts, chlorinated derivatives of paraffin, and polyether polyurethane oligomers, and its number average molecular weight is preferably 150-3000 g / mol, more preferably 250-1500 g / mol; its water absorption rate is preferably ≤5%, more preferably ≤2%.

5. A method for preparing the sulfonic acid type waterborne polyurethane composite with low water absorption according to any one of claims 1 to 4, characterized in that: The following steps are involved: 1) Component S1, component S2, component S3, component S8, part of component S9 and optional component S5-1 are mixed and reacted at 65-85° C. until NCO reaches a theoretical value to form a diisocyanate-terminated prepolymer; 2) cooling the prepolymer obtained in step 1) to 25-55° C., adding component S6 and the remaining S9, and stirring and mixing uniformly; 3) adding component S4 and optional component S5-2 to the prepolymer dilution obtained in step 2), and reacting at 25-55° C. for 5-25 min; 4) adding component S7 to the polyurethane solution obtained in step 3) under high-speed stirring to obtain a crude emulsion, and removing the solvent to obtain a sulfonic acid-type waterborne polyurethane composite with low water absorption; Among them, at least one of component S5-1 and component S5-2 is added.

6. The preparation method according to claim 5, characterized in that: In step 1) and step 2), the mass ratio of component S9 added is 1 / (6-15); Preferably, in step 3), the component S4 and the optional component S5-2 are added in the form of an aqueous solution or an acetone solution, and the amount of water or acetone used is 1-20 times the total mass of the component S4 and the component S5-2.

7. The preparation method according to claim 5, characterized in that: The prepared sulfonic acid type waterborne polyurethane composite with low water absorption rate is in the form of emulsion, the solid content of the emulsion is 40-65%, and the particle size is 180-650nm.

8. A water-based polyurethane waterproof coating, characterized in that: The invention comprises the sulfonic acid type waterborne polyurethane composite with low water absorption rate as described in any one of claims 1 to 4 or the sulfonic acid type waterborne polyurethane composite with low water absorption rate prepared by the preparation method as described in any one of claims 5 to 7.

9. The waterborne polyurethane waterproof coating according to claim 8, characterized in that: It also includes one or more of a pigment, a filler, a dispersant, a defoaming agent, a film-forming aid, a stabilizer, a wetting agent, and a thickener.

10. The use of the waterborne polyurethane waterproof coating according to claim 8 or 9 in the field of building waterproofing is particularly suitable for waterproofing of roofs, exterior walls, toilets, kitchens and basements.

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