A polyurethane waterproof coating and its preparation method

Abstract

The present invention discloses a polyurethane waterproof coating and a preparation method thereof, relating to the technical field of coating paints. When preparing the polyurethane waterproof coating of the present invention, pretreated nano-silica is prepared by reacting nano-silica and (triethoxysilyl) methanol, and modified nano-silica is prepared by polymerizing allyl dichlorophosphine and 1,12-dodecanediol on the surface of the pretreated nano-silica; 2-allyl-2-methyl-1,3-propanediol, hexamethylene diisocyanate, and dihydroxypropyl octamethyltetrasiloxane are reacted to prepare polyurethane; the polyurethane, modified nano-silica, hydrogen-containing silicone oil, chloroplatinic acid, and various additives are mixed evenly, and coated and cured to prepare the polyurethane waterproof coating. The polyurethane waterproof coating prepared by the present invention has good waterproofness, tensile strength, and flame retardancy.

Description

Technical Field

[0001] The present invention relates to the technical field of coating materials, and specifically to a polyurethane waterproof coating and a preparation method thereof. Background Art

[0002] Polyurethane is one of the most common, widely used and most studied materials in the world. It can combine the durability and toughness of metals with the elasticity of rubber, making it a suitable substitute for several engineering products such as metals, plastics and rubbers. Polyurethane materials have currently been used in various types of industrial equipment and are used to manufacture a variety of commercial products, commonly including paints, liquid coatings, elastomers, rigid insulating materials, elastic fibers, soft foams, and even used as integral skins.

[0003] Polyurethane is made from a variety of diisocyanates, a variety of polyols, other chain extenders and crosslinking agents. Therefore, polyurethane products with customized functions can be synthesized according to monomers with different characteristics, which can meet the applications in many specific situations. Polyurethane has defects such as poor water resistance, insufficient mechanical strength due to its simple structure and small molecular weight, and relatively low flame retardancy. Therefore, to further expand the application scope and effect of polyurethane, corresponding modification is required. Summary of the Invention

[0004] The purpose of the present invention is to provide a polyurethane waterproof coating and a preparation method thereof to solve the problems existing in the prior art.

[0005] A polyurethane waterproof coating, characterized in that the polyurethane waterproof coating is formed by uniformly mixing polyurethane, modified nano-silica, hydrogen-containing silicone oil, chloroplatinic acid and various additives, and then coating and curing.

[0006] Preferably, the polyurethane is prepared by reacting 2-allyl-2-methyl-1,3-propanediol, hexamethylene diisocyanate and dihydroxypropyl octamethyltetrasiloxane.

[0007] Preferably, the modified nano-silica is prepared by reacting nano-silica with (triethoxysilyl) methanol to obtain pretreated nano-silica, and then polymerizing allyl dichlorophosphine and 1,12-dodecanediol on the surface of the pretreated nano-silica.

[0008] Preferably, the preparation mainly includes the following steps:

[0009] (1) In a nitrogen atmosphere, pretreated nano-silica, allylphosphonous dichloride, and tetrahydrofuran are mixed evenly in a mass ratio of 1:2:30 - 40. During the reaction, the pH is controlled at 7.5 - 8 by adding potassium carbonate. At 0 - 2 °C, ultrasonic dispersion is carried out at 25 - 35 kHz for 20 - 30 min, then continue ultrasonic and heat up to 20 - 30 °C. Add 1,12-dodecanediol, which is 0.1 times the molar amount of allylphosphonous dichloride, every 30 min, and add a total of 7 - 9 times. After the addition, continue ultrasonic reaction for 6 - 8 h, then centrifuge and wash with pure water 3 - 5 times to obtain modified nano-silica;

[0010] (2) In a nitrogen atmosphere, 2-allyl-2-methyl-1,3-propanediol and ethyl acetate are mixed evenly in a mass ratio of 1:3 - 4. Add hexamethylene diisocyanate, which is 2 - 3 times the molar amount of 2-allyl-2-methyl-1,3-propanediol, and stir at 10 - 30 °C and 300 - 500 r / min for 10 - 15 min. Then heat up to 60 - 70 °C and continue stirring for 25 - 30 min. Then add dibutyltin dilaurate, which is 0.003 - 0.005 times, and continue the reaction for 2 - 3 h under the condition of keeping the temperature and stirring unchanged. Heat up to 80 - 85 °C and continue stirring. Add dihydroxypropyl octamethyltetrasiloxane, which is 0.1 times the mass of hexamethylene diisocyanate, every 10 min. Measure the actual remaining amount of isocyanate in the reaction. When the actual remaining amount of isocyanate is less than 1% of the initial amount of isocyanate, stop adding dihydroxypropyl octamethyltetrasiloxane and end the reaction. Let it stand at 80 - 90 °C and 1 - 2 kPa for 6 - 8 h to obtain polyurethane;

[0011] (3) Weigh the following components by mass parts: 60 - 120 parts of polyurethane, 10 - 20 parts of modified nano-silica, 8 - 12 parts of hydrogen-containing silicone oil, 1 - 2 parts of chloroplatinic acid, 10 - 20 parts of viscosity reducer, 5 - 10 parts of talcum powder, 10 - 25 parts of latent curing agent, 3 - 5 parts of water remover, 1 - 2 parts of defoaming agent, 2 - 4 parts of coupling agent, 1 - 2 parts of ultraviolet light absorber, 1 - 2 parts of anti-aging agent, 8 - 10 parts of pigment, 3 - 5 parts of activator; Mix the weighed components evenly, stir at 60 - 70 °C and 500 - 700 r / min for 8 - 10 min, and coat at a rate of 0.05 - 0.1 g / cm 2 . Let it stand at 60 - 70 °C for 20 - 30 min, then heat up to 90 - 100 °C and let it stand for 20 - 30 min. After cooling to room temperature, continue to let it stand for 20 - 24 h to obtain a polyurethane waterproof coating.

[0012] As an optimization, the preparation method of the pretreated nano-silica in step (1) is as follows: Mix nano-silica, absolute ethanol, and pure water evenly according to a mass ratio of 1:6-10:2-3, perform ultrasonic dispersion at 10-30°C and 25-35 kHz for 40-60 min, then add (triethoxysilyl) methanol which is 0.3-0.4 times the mass of the nano-silica, and continue the reaction for 6-8 h. Centrifuge and wash with absolute ethanol 3-5 times, and dry at 60-70°C for 6-8 h to prepare it.

[0013] As an optimization, the preparation method of the dihydroxypropyl octamethyltetrasiloxane in step (2) is as follows:

[0014] Add 1,1,3,3,5,5,7,7-octamethyltetrasiloxane and allyl alcohol according to a molar ratio of 1:2 to n-hexane which is 6-8 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane, and add chloroplatinic acid which is 0.03-0.05 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane. Stir and reflux at 70-80°C and 500-800 r / min for 4-6 h, and let it stand at 60-70°C and 1-2 kPa for 3-4 h to prepare it.

[0015] As an optimization, the determination method used to measure the actual remaining amount of isocyanate in the reaction in step (2) is the toluene-di-n-butylamine titration method.

[0016] As an optimization, the model of the hydrogen-containing silicone oil in step (3) is MHX-1107.

[0017] As an optimization, the silane coupling agent in step (3) is triethoxysilane.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0019] When preparing the polyurethane waterproof coating in the present invention, polyurethane, modified nano-silica, hydrogen-containing silicone oil, silane coupling agent, chloroplatinic acid, and various additives are mixed evenly, and then coated and cured to obtain the polyurethane waterproof coating.

[0020] First, the pretreated nano-silica is prepared by reacting nano-silica with (triethoxysilyl) methanol. The modified nano-silica is prepared by polymerizing allyl dichlorophosphine and 1,12-dodecanediol on the surface of the pretreated nano-silica. Allyl dichlorophosphine and 1,12-dodecanediol form a polymer long chain with a structure of allyl phosphine-oxygen-dodecane on the surface of the nano-silica, which improves the dispersibility. And the dodecane chain segment has good hydrophobicity, thus improving the waterproof property. The polymer long chain contains a large amount of phosphorus elements, which can be used as a charring agent to improve the flame retardancy. And the carbon-carbon double bonds on the polymer long chain can react with the hydrogen-containing silicone oil during curing to form a cross-linked network structure, thus improving the tensile strength.

[0021] Secondly, 2 - allyl - 2 - methyl - 1,3 - propanediol, hexamethylene diisocyanate, and dihydroxypropyl octamethyltetrasiloxane are reacted to prepare polyurethane. The introduction of carbon - carbon double bonds by 2 - allyl - 2 - methyl - 1,3 - propanediol enables it to react with hydrogen - containing silicone oil, improving the tensile strength. Dihydroxypropyl octamethyltetrasiloxane can form a silicone - oxygen hydrophobic segment in the polyurethane, thereby improving the waterproof property. Moreover, the silicone - oxygen hydrophobic segment can form silicon dioxide at high temperatures to cover the surface and block oxygen and heat, thus improving the flame - retardant property. Detailed implementation manners

[0022] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] In order to more clearly illustrate the method provided by the present invention, it is described in detail through the following embodiments. The test methods for each index of the polyurethane waterproof coating prepared in the following embodiments are as follows:

[0024] Waterproof property: Take the polyurethane waterproof coatings obtained in each embodiment and the control - sample material with the same area size. Place the waterproof surface upwards and fix it flat on a glass plate with double - sided tape for horizontal placement. Drop the same volume of pure water on the surface in the same environmental atmosphere, tilt the glass plate until the water droplets on each component material roll, and record the rolling angle.

[0025] Tensile strength: For the polyurethane waterproof coatings obtained in each embodiment and the control - sample material, according to the GB / T1040 standard, the size of the rubber film is made into a standard dumbbell shape by a cutter, and an electronic tensile machine is used to measure the mechanical properties of the rubber film.

[0026] Flame - retardant property: For the polyurethane waterproof coatings obtained in each embodiment and the control - sample material, according to the ASTM D 2863 standard, the LOI value.

[0027] The following Table 1 shows the sources and specifications of various additives used in the embodiments and control examples of the present invention:

[0028] Table 1

[0029] Name Manufacturer Specification Viscosity reducer TXIB from the United States 6846-50-0 Talc powder Lingshou County Yunshi Mineral Products Processing Factory 1250 mesh Latent curing agent Wanhua Chemical Group Co., Ltd. HT100 Water remover Shanghai Deyude Trading Co., Ltd. Density 1.29 g / cm3 Defoaming agent Dachuan Fine Chemical Co., Ltd. H530 Coupling agent Guangzhou Kuibang Chemical Co., Ltd. 550 Ultraviolet light absorber BASF tinuvin1130 Anti-aging agent Guangzhou Good New Materials Technology Co., Ltd. V-990 Pigment Orion from Germany Printex U pigment carbon black Activator Jiangxi Xintao Technology Co., Ltd. 3A

[0030] Example 1

[0031] A preparation method of a polyurethane waterproof coating, the preparation method of the polyurethane waterproof coating mainly includes the following preparation steps:

[0032] (1) Mix nano-silica, absolute ethanol, and pure water evenly at a mass ratio of 1:6:2, ultrasonically disperse them at 10 °C and 25 kHz for 60 min, then add (triethoxysilyl) methanol which is 0.3 times the mass of the nano-silica, and continue the reaction for 8 h. Centrifuge and wash with absolute ethanol 3 times, and dry at 60 °C for 8 h to obtain pretreated nano-silica; in a nitrogen atmosphere, mix pretreated nano-silica, allyl dichlorophosphine, and tetrahydrofuran evenly at a mass ratio of 1:2:40. During the reaction, control the pH at 7.5 by adding potassium carbonate, ultrasonically disperse at 1 °C and 25 kHz for 30 min, continue ultrasonic treatment and heat up to 20 °C, add 1,12-dodecanediol which is 0.1 times the molar amount of allyl dichlorophosphine every 30 min, add a total of 7 times. After the addition, continue ultrasonic reaction for 6 h, centrifuge and wash with pure water 3 times to obtain modified nano-silica;

[0033] (2) Add 1,1,3,3,5,5,7,7-octamethyltetrasiloxane and allyl alcohol at a molar ratio of 1:2 to n-hexane which is 6 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane, and add chloroplatinic acid which is 0.03 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane. Stir and reflux at 70 °C and 500 r / min for 6 h, and let it stand at 60 °C and 1 kPa for 4 h to obtain dihydroxypropyl octamethyltetrasiloxane; in a nitrogen atmosphere, mix 2-allyl-2-methyl-1,3-propanediol and ethyl acetate evenly at a mass ratio of 1:3, add hexamethylene diisocyanate which is 2 times the molar amount of 2-allyl-2-methyl-1,3-propanediol, and stir at 10 °C and 300 r / min for 15 min, then heat up to 60 °C and continue stirring for 25 min, then add 0.003 times of dibutyltin dilaurate, keep the temperature and stirring conditions unchanged and continue the reaction for 2 h, heat up to 80 °C and continue stirring, add dihydroxypropyl octamethyltetrasiloxane which is 0.1 times the mass of hexamethylene diisocyanate every 10 min. Use the toluene-din-butylamine titration method to measure the actual remaining isocyanate amount in the reaction. When the actual remaining isocyanate amount is less than 1% of the initial isocyanate amount, stop adding dihydroxypropyl octamethyltetrasiloxane and end the reaction. Let it stand at 80 °C and 1 kPa for 8 h to obtain polyurethane;

[0034] (3) Weigh the following components by mass parts: 60 parts of polyurethane, 10 parts of modified nano-silica, 8 parts of MHX-1107 hydrogen-containing silicone oil, 1 part of chloroplatinic acid, 10 parts of viscosity reducer, 5 parts of talcum powder, 10 parts of latent curing agent, 3 parts of water remover, 1 part of defoaming agent, 2 parts of coupling agent, 1 part of ultraviolet light absorber, 1 part of anti-aging agent, 8 parts of pigment, 3 parts of activator; mix the weighed components evenly, stir at 60 °C and 500 r / min for 10 min, at 0.1 g / cm 2Coat it according to the amount, let it stand at 60 °C for 30 min, then raise the temperature to 90 °C and let it stand for 30 min. After cooling to room temperature, continue to let it stand for 20 h to obtain a polyurethane waterproof coating.

[0035] Example 2

[0036] A preparation method of a polyurethane waterproof coating, the preparation method of the polyurethane waterproof coating mainly includes the following preparation steps:

[0037] (1) Mix nano-silica, absolute ethanol, and pure water evenly according to a mass ratio of 1:8:2.5, disperse them ultrasonically at 20 °C and 30 kHz for 50 min, then add (triethoxysilyl) methanol which is 0.35 times the mass of nano-silica, and continue to react for 7 h. Centrifuge and wash with absolute ethanol 4 times, and dry at 65 °C for 7 h to obtain pretreated nano-silica; in a nitrogen atmosphere, mix pretreated nano-silica, allyl dichlorophosphine, and tetrahydrofuran evenly according to a mass ratio of 1:2:35, control the pH at 7.8 by adding potassium carbonate during the reaction, disperse ultrasonically at 1 °C and 30 kHz for 25 min, continue ultrasonic dispersion and raise the temperature to 25 °C, add 1,12-dodecanediol which is 0.1 times the molar amount of allyl dichlorophosphine every 30 min, add a total of 8 times, after the addition, continue ultrasonic reaction for 7 h, centrifuge and wash with pure water 4 times to obtain modified nano-silica;

[0038] (2) Add 1,1,3,3,5,5,7,7-octamethyltetrasiloxane and allyl alcohol into n-hexane which is 7 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane according to a molar ratio of 1:2, and add chloroplatinic acid which is 0.04 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane, stir and reflux at 75 °C and 600 r / min for 5 h, stand at 65 °C and 1.5 kPa for 4 h to obtain dihydroxypropyl octamethyltetrasiloxane; in a nitrogen atmosphere, mix 2-allyl-2-methyl-1,3-propanediol and ethyl acetate evenly according to a mass ratio of 1:3.5, add hexamethylene diisocyanate which is 2.5 times the molar amount of 2-allyl-2-methyl-1,3-propanediol, and stir at 20 °C and 400 r / min for 12 min, then raise the temperature to 65 °C and continue to stir for 28 min, then add 0.004 times of dibutyltin dilaurate, keep the temperature and stirring conditions unchanged and continue to react for 2.5 h, raise the temperature to 82 °C and continue to stir, add dihydroxypropyl octamethyltetrasiloxane which is 0.1 times the mass of hexamethylene diisocyanate every 10 min, use the toluene - di-n-butylamine titration method to measure the actual remaining isocyanate amount in the reaction, when the actual remaining isocyanate amount is less than 1% of the initial isocyanate amount, stop adding hydroxypropyl octamethyltetrasiloxane and end the reaction, stand at 85 °C and 1.5 kPa for 7 h to obtain polyurethane;

[0039] (3) Weigh the following components by mass parts: 80 parts of polyurethane, 15 parts of modified nano-silica, 10 parts of MHX-1107 hydrogen-containing silicone oil, 1.5 parts of chloroplatinic acid, 15 parts of viscosity reducer, 8 parts of talcum powder, 17 parts of latent curing agent, 4 parts of water remover, 1.5 parts of defoaming agent, 3 parts of coupling agent, 1.5 parts of ultraviolet light absorber, 1.5 parts of anti-aging agent, 9 parts of pigment, 4 parts of activator; Mix the weighed components evenly, stir at 65 °C and 600 r / min for 9 min, and coat at a rate of 0.1 g / cm 2 , let it stand at 65 °C for 25 min, then raise the temperature to 95 °C and let it stand for 25 min. After cooling to room temperature, continue to let it stand for 22 h to obtain a polyurethane waterproof coating.

[0040] Example 3

[0041] A preparation method of a polyurethane waterproof coating, the preparation method of the polyurethane waterproof coating mainly includes the following preparation steps:

[0042] (1) Mix nano-silica, absolute ethanol, and pure water evenly according to a mass ratio of 1:10:3, ultrasonically disperse at 30 °C and 35 kHz for 40 min, then add (triethoxysilyl) methanol which is 0.4 times the mass of nano-silica, and continue to react for 8 h. Centrifuge and wash with absolute ethanol 5 times, and dry at 70 °C for 6 h to obtain pretreated nano-silica; In a nitrogen atmosphere, mix pretreated nano-silica, allyl dichlorophosphine, and tetrahydrofuran evenly according to a mass ratio of 1:2:40. During the reaction, control the pH at 8 by adding potassium carbonate, ultrasonically disperse at 2 °C and 35 kHz for 20 min, continue ultrasonic treatment and raise the temperature to 30 °C, add 1,12-dodecanediol which is 0.1 times the molar amount of allyl dichlorophosphine every 30 min, add a total of 9 times. After the addition is completed, continue ultrasonic reaction for 6 h. Centrifuge and wash with pure water 5 times to obtain modified nano-silica;

[0043] (2) 1,1,3,3,5,5,7,7 - Octamethyltetrasiloxane and allyl alcohol were added to n - hexane in a mass ratio of 1:2 and 6 - 8 times the mass of 1,1,3,3,5,5,7,7 - octamethyltetrasiloxane. Chloroplatinic acid with a mass of 0.05 times that of 1,1,3,3,5,5,7,7 - octamethyltetrasiloxane was added. The mixture was stirred and refluxed at 80 °C and 500 r / min for 6 h, and then left to stand at 60 °C and 1 kPa for 4 h to obtain dihydroxypropyl octamethyltetrasiloxane. In a nitrogen atmosphere, 2 - allyl - 2 - methyl - 1,3 - propanediol and ethyl acetate were mixed evenly in a mass ratio of 1:3. Hexamethylene diisocyanate with a molar amount 2 times that of 2 - allyl - 2 - methyl - 1,3 - propanediol was added, and the mixture was stirred at 10 °C and 300 r / min for 15 min. Then the temperature was raised to 60 °C and stirring continued for 25 min. Then 0.003 times dibutyltin dilaurate was added, and the reaction continued for 3 h while maintaining the temperature and stirring conditions. The temperature was raised to 80 °C and stirring continued. Dihydroxypropyl octamethyltetrasiloxane with a mass of 0.1 times that of hexamethylene diisocyanate was added every 10 min. The actual remaining amount of isocyanate in the reaction was determined by the toluene - di - n - butylamine titration method. When the actual remaining amount of isocyanate was less than 1% of the initial amount of isocyanate, the addition of dihydroxypropyl octamethyltetrasiloxane was stopped and the reaction ended. The mixture was left to stand at 90 °C and 2 kPa for 6 h to obtain polyurethane.

[0044] (3) Weigh the following components by mass parts: 120 parts of polyurethane, 20 parts of modified nano - silica, 12 parts of MHX - 1107 hydrogen - containing silicone oil, 2 parts of chloroplatinic acid, 20 parts of viscosity reducer, 10 parts of talcum powder, 25 parts of latent curing agent, 5 parts of water remover, 2 parts of defoaming agent, 4 parts of coupling agent, 2 parts of ultraviolet light absorber, 2 parts of anti - aging agent, 10 parts of pigment, 5 parts of activator. Mix the weighed components evenly, stir at 70 °C and 700 r / min for 8 min, coat at a rate of 0.1 g / cm², leave to stand at 70 °C for 30 min, then raise the temperature to 100 °C and leave to stand for 20 min. After cooling to room temperature, leave to stand for another 24 h to obtain a polyurethane waterproof coating.

[0045] Comparative Example 1

[0046] A preparation method of a polyurethane waterproof coating, the preparation method of the polyurethane waterproof coating mainly includes the following preparation steps:

[0047] (1) 1,1,3,3,5,5,7,7 - octamethyltetrasiloxane and allyl alcohol were added to n - hexane which was 7 times the mass of 1,1,3,3,5,5,7,7 - octamethyltetrasiloxane at a molar ratio of 1:2, and chloroplatinic acid which was 0.04 times the mass of 1,1,3,3,5,5,7,7 - octamethyltetrasiloxane was added. The mixture was stirred and refluxed at 75 °C and 600 r / min for 5 h, and then left to stand at 65 °C and 1.5 kPa for 4 h to obtain dihydroxypropyl octamethyltetrasiloxane. In a nitrogen atmosphere, 2 - allyl - 2 - methyl - 1,3 - propanediol and ethyl acetate were mixed evenly at a mass ratio of 1:3.5, and hexamethylene diisocyanate which was 2.5 times the molar amount of 2 - allyl - 2 - methyl - 1,3 - propanediol was added. The mixture was stirred at 20 °C and 400 r / min for 12 min, then heated to 65 °C and stirred for another 28 min. Then 0.004 times of dibutyltin dilaurate was added, and the reaction continued for 2.5 h while maintaining the temperature and stirring conditions unchanged. The temperature was raised to 82 °C and stirring continued. Dihydroxypropyl octamethyltetrasiloxane which was 0.1 times the mass of hexamethylene diisocyanate was added every 10 min. The actual remaining amount of isocyanate in the reaction was determined by the toluene - di - n - butylamine titration method. When the actual remaining amount of isocyanate was less than 1% of the initial amount of isocyanate, the addition of dihydroxypropyl octamethyltetrasiloxane was stopped and the reaction was ended. The mixture was left to stand at 85 °C and 1.5 kPa for 7 h to obtain polyurethane.

[0048] (2) The following components were weighed by mass fraction: 80 parts of polyurethane, 15 parts of nano - silica, 10 parts of MHX - 1107 hydrogen - containing silicone oil, 1.5 parts of chloroplatinic acid, 15 parts of viscosity - reducing agent, 8 parts of talcum powder, 17 parts of latent curing agent, 4 parts of water - removing agent, 1.5 parts of defoaming agent, 3 parts of coupling agent, 1.5 parts of ultraviolet light absorber, 1.5 parts of anti - aging agent, 9 parts of pigment, 4 parts of activator. The weighed components were mixed evenly and stirred at 65 °C and 600 r / min for 9 min, and then coated at a rate of 0.1 g / cm 2 . It was left to stand at 65 °C for 25 min, then heated to 95 °C and left to stand for 25 min. After cooling to room temperature, it was left to stand for another 22 h to obtain a polyurethane waterproof coating.

[0049] Comparative Example 2

[0050] A preparation method of a polyurethane waterproof coating, the preparation method of the polyurethane waterproof coating mainly includes the following preparation steps:

[0051] (1) Nano-silica, anhydrous ethanol and pure water were mixed in a mass ratio of 1:8:2.5, and ultrasonically dispersed at 20°C and 30kHz for 50 minutes, and then (triethoxysilyl) methanol was added in an amount of 0.35 times the mass of the nano-silica, and the reaction was continued for 7 hours, centrifuged and washed with anhydrous ethanol 4 times, and dried at 65°C for 7 hours to obtain pretreated nano-silica; in a nitrogen atmosphere, the pretreated nano-silica, allyl phosphine dichloride and tetrahydrofuran were mixed in a mass ratio of 1:2:35, and the pH was controlled at 7.8 by adding potassium carbonate during the reaction, and ultrasonically dispersed at 1°C and 30kHz for 25 minutes, and the ultrasonic wave was continued and the temperature was raised to 25°C, and 1,12-dodecanediol was added in an amount of 0.1 times the molar amount of allyl phosphine dichloride every 30 minutes for a total of 8 times, and the ultrasonic reaction was continued for 7 hours after the addition was completed, and the mixture was centrifuged and washed with pure water 4 times to obtain modified nano-silica;

[0052] (2) 1,1,3,3,5,5,7,7-octamethyltetrasiloxane and allyl alcohol were added in a molar ratio of 1:2 to n-hexane (7 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane), and chloroplatinic acid (0.04 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane) was added, and the mixture was stirred and refluxed at 75°C and 600 r / min for 5 hours, and allowed to stand at 65°C and 1.5 kPa for 4 hours to obtain dihydroxypropyl octamethyltetrasiloxane; in a nitrogen atmosphere, neopentyl glycol and ethyl acetate were uniformly mixed in a mass ratio of 1:3.5, and hexamethylene diisocyanate (2.5 times the molar amount of neopentyl glycol) was added, and The mixture was stirred at 20°C and 400 r / min for 12 minutes, then heated to 65°C and stirred for 28 minutes, and then 0.004 times of dibutyltin dilaurate was added, and the temperature and stirring conditions were kept unchanged and the reaction was continued for 2.5 hours. The mixture was heated to 82°C and stirred, and 0.1 times of the mass of hexamethylene diisocyanate dihydroxypropyl octamethyltetrasiloxane was added every 10 minutes. The actual amount of isocyanate remaining in the reaction was determined by toluene-di-n-butylamine titration method. When the actual amount of isocyanate remaining was less than 1% of the initial amount of isocyanate, the addition of hydroxypropyl octamethyltetrasiloxane was stopped, the reaction was terminated, and the mixture was allowed to stand at 85°C and 1.5 kPa for 7 hours to obtain polyurethane.

[0053] (3) Weigh the following components by mass: 80 parts of polyurethane, 15 parts of modified nano-silica, 10 parts of MHX-1107 hydrogenated silicone oil, 1.5 parts of chloroplatinic acid, 15 parts of viscosity reducer, 8 parts of talc, 17 parts of latent curing agent, 4 parts of dewatering agent, 1.5 parts of defoaming agent, 3 parts of coupling agent, 1.5 parts of ultraviolet light absorber, 1.5 parts of anti-aging agent, 9 parts of pigment, and 4 parts of activator; mix the weighed components evenly, stir at 65°C and 600 r / min for 9 min, and heat to 0.1 g / cm 2Coat it according to the amount, let it stand at 65°C for 25 min, then heat it up to 95°C and let it stand for 25 min. After cooling to room temperature, continue to let it stand for 22 h to obtain a polyurethane waterproof coating.

[0054] Comparative Example 3

[0055] A preparation method of a polyurethane waterproof coating, the preparation method of the polyurethane waterproof coating mainly includes the following preparation steps:

[0056] (1) Mix nano-silica, absolute ethanol, and pure water evenly according to a mass ratio of 1:8:2.5, perform ultrasonic dispersion at 20°C and 30 kHz for 50 min, then add (triethoxysilyl) methanol with a mass 0.35 times that of the nano-silica, and continue to react for 7 h. Centrifuge and wash 4 times with absolute ethanol, and dry at 65°C for 7 h to obtain pretreated nano-silica; in a nitrogen atmosphere, mix the pretreated nano-silica, allyl dichlorophosphine, and tetrahydrofuran evenly according to a mass ratio of 1:2:35, control the pH at 7.8 by adding potassium carbonate during the reaction, perform ultrasonic dispersion at 1°C and 30 kHz for 25 min, continue ultrasonic treatment and heat up to 25°C, add 1,12-dodecanediol with a molar amount 0.1 times that of allyl dichlorophosphine every 30 min, add a total of 8 times, and continue ultrasonic reaction for 7 h after the addition. Centrifuge and wash 4 times with pure water to obtain modified nano-silica;

[0057] (2) In a nitrogen atmosphere, mix 2-allyl-2-methyl-1,3-propanediol and ethyl acetate evenly according to a mass ratio of 1:3.5, add hexamethylene diisocyanate with a molar amount 2.5 times that of 2-allyl-2-methyl-1,3-propanediol, and stir at 20°C and 400 r / min for 12 min. Then heat up to 65°C and continue stirring for 28 min. Then add 0.004 times of dibutyltin dilaurate, keep the temperature and stirring conditions unchanged and continue to react for 2.5 h. Heat up to 82°C and continue stirring, add 2-allyl-2-methyl-1,3-propanediol with a mass 0.1 times that of hexamethylene diisocyanate every 10 min. Use the toluene-dibutylamine titration method to measure the actual remaining isocyanate amount in the reaction. When the actual remaining isocyanate amount is less than 1% of the initial isocyanate amount, stop adding hydroxypropyl octamethyltetrasiloxane and end the reaction. Let it stand at 85°C and 1.5 kPa for 7 h to obtain polyurethane;

[0058] (3) Weigh the following components by mass parts: 80 parts of polyurethane, 15 parts of modified nano-silica, 10 parts of MHX-1107 hydrogen-containing silicone oil, 1.5 parts of chloroplatinic acid, 15 parts of viscosity reducer, 8 parts of talcum powder, 17 parts of latent curing agent, 4 parts of water remover, 1.5 parts of defoaming agent, 3 parts of coupling agent, 1.5 parts of ultraviolet light absorber, 1.5 parts of anti-aging agent, 9 parts of pigment, 4 parts of activator; Mix the weighed components evenly, stir at 65 °C and 600 r / min for 9 min, and coat at a rate of 0.1 g / cm 2 Then leave it to stand at 65 °C for 25 min, then raise the temperature to 95 °C and leave it to stand for 25 min. After cooling to room temperature, continue to leave it to stand for 22 h to obtain a polyurethane waterproof coating.

[0059] Effect Example

[0060] Table 2 below gives the analysis results of the waterproofness and antibacterial properties of the polyurethane waterproof coatings prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0061] Table 2

[0062] Rolling angle Tensile strength LOI value Rolling angle Tensile strength LOI value Example 1 4.2° 29.7 MPa 31.3％ Comparative Example 1 10.6° 23.4 MPa 26.1％ Example 2 3.9° 29.9 MPa 31.6％ Comparative Example 2 4.5° 25.8 MPa 31.0％ Example 3 4.0° 30.0 MPa 31.7％ Comparative Example 3 9.2° 39.5 MPa 26.7％

[0063] It can be found from the comparison of the experimental data in Table 2 that the polyurethane waterproof coating prepared by the present invention has good waterproofness, tensile strength and flame retardancy.

[0064] It can be found from the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 1 that Examples 1, 2, 3 have a smaller rolling angle, higher tensile strength and LOI value compared to Comparative Example 1. This shows that after modifying nano-silica, allylphosphine dichloride and 1,12-dodecanediol form a polymer long chain with the structure of allylphosphine-oxygen-dodecane on the surface of nano-silica, improving the dispersibility. And the dodecane chain segment has good hydrophobicity, thus improving the waterproofness. The polymer long chain contains a large amount of phosphorus elements, which can be used as a charring agent to improve the flame retardancy. And the carbon-carbon double bonds on the polymer long chain can react with hydrogen-containing silicone oil during curing to form a cross-linked network structure, thus improving the tensile strength. It can be found from the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 2 that Examples 1, 2, 3 have a higher tensile strength compared to Comparative Example 2. This shows that adding 2-allyl-2-methyl-1,3-propanediol during the preparation of polyurethane makes the polyurethane have a large number of carbon-carbon double bonds, which can react with hydrogen-containing silicone oil during curing to form a cross-linked network structure, thus improving the tensile strength. It can be found from the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 3 that Examples 1, 2, 3 have a smaller rolling angle and higher LOI value compared to Comparative Example 3. This shows that adding dihydroxypropyl octamethyltetrasiloxane during the preparation of polyurethane can form a silicon-oxygen hydrophobic chain segment in the polyurethane, thus improving the waterproofness. And the silicon-oxygen hydrophobic chain segment can form silica at high temperature to cover the surface and block oxygen and heat, thus improving the flame retardancy.

[0065] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claim concerned.

Claims

1. A polyurethane waterproof coating, characterized in that, the polyurethane waterproof coating is formed by uniformly mixing polyurethane, modified nano-silica, hydrogen-containing silicone oil, chloroplatinic acid and various additives, and then coating and curing; the various additives include viscosity reducer, talcum powder, latent curing agent, water remover, defoaming agent, coupling agent, ultraviolet absorber, anti-aging agent, pigment, activator; the polyurethane is prepared by reacting 2-allyl-2-methyl-1,3-propanediol, hexamethylene diisocyanate and dihydroxypropyl octamethyltetrasiloxane; the modified nano-silica is prepared by reacting nano-silica with (triethoxysilyl) methanol to obtain pretreated nano-silica, and then polymerizing allyl dichlorophosphine and 1,12-dodecanediol on the surface of the pretreated nano-silica; when the polyurethane waterproof coating is cured, both the polyurethane and the modified nano-silica react and crosslink with the hydrogen-containing silicone oil.

2. A preparation method of a polyurethane waterproof coating, characterized in that, it mainly includes the following preparation steps: (1) In a nitrogen atmosphere, uniformly mix pretreated nano-silica, allyl dichlorophosphine and tetrahydrofuran according to a mass ratio of 1:2:30 - 40, control the pH at 7.5 - 8 by adding potassium carbonate during the reaction, perform ultrasonic dispersion at 0 - 2 °C and 25 - 35 kHz for 20 - 30 min, continue ultrasonic treatment and heat up to 20 - 30 °C, add 1,12-dodecanediol with a molar amount 0.1 times that of allyl dichlorophosphine every 30 min, add a total of 7 - 9 times, continue ultrasonic reaction for 6 - 8 h after the addition, perform centrifugal separation and wash with pure water 3 - 5 times to obtain modified nano-silica; (2) In a nitrogen atmosphere, uniformly mix 2-allyl-2-methyl-1,3-propanediol and ethyl acetate according to a mass ratio of 1:3 - 4, add hexamethylene diisocyanate with a molar amount 2 - 3 times that of 2-allyl-2-methyl-1,3-propanediol, stir at 10 - 30 °C and 300 - 500 r / min for 10 - 15 min, then heat up to 60 - 70 °C and continue stirring for 25 - 30 min, then add 0.003 - 0.005 times of dibutyltin dilaurate, keep the temperature and stirring conditions unchanged and continue to react for 2 - 3 h, heat up to 80 - 85 °C and continue stirring, add dihydroxypropyl octamethyltetrasiloxane with a mass 0.1 times that of hexamethylene diisocyanate every 10 min, measure the actual remaining isocyanate amount in the reaction, stop adding dihydroxypropyl octamethyltetrasiloxane when the actual remaining isocyanate amount is less than 1% of the initial isocyanate amount, end the reaction, and let it stand at 80 - 90 °C and 1 - 2 kPa for 6 - 8 h to obtain polyurethane; (3) Weigh the following components by mass parts: 60 - 120 parts of polyurethane, 10 - 20 parts of modified nano-silica, 8 - 12 parts of hydrogen-containing silicone oil, 1 - 2 parts of chloroplatinic acid, 10 - 20 parts of viscosity reducer, 5 - 10 parts of talcum powder, 10 - 25 parts of latent curing agent, 3 - 5 parts of water remover, 1 - 2 parts of defoaming agent, 2 - 4 parts of coupling agent, 1 - 2 parts of ultraviolet light absorber, 1 - 2 parts of anti-aging agent, 8 - 10 parts of pigment, 3 - 5 parts of activator; Mix the weighed components evenly, stir at 60 - 70 °C and 500 - 700 r / min for 8 - 10 min, and coat at a rate of 0.05 - 0.1 g / cm 2 . Let it stand at 60 - 70 °C for 20 - 30 min, then raise the temperature to 90 - 100 °C and let it stand for 20 - 30 min. After cooling to room temperature, continue to let it stand for 20 - 24 h to obtain a polyurethane waterproof coating.

3. According to the preparation method of a polyurethane waterproof coating described in claim 2, characterized in that, The preparation method of the pretreated nano-silica in step (1) is as follows: Mix nano-silica, absolute ethanol, and pure water evenly according to a mass ratio of 1:6-10:2-3, perform ultrasonic dispersion at 10-30 °C and 25-35 kHz for 40-60 min, then add (triethoxysilyl) methanol which is 0.3-0.4 times the mass of the nano-silica, and continue to react for 6-8 h. Centrifuge and wash with absolute ethanol 3-5 times, and dry at 60-70 °C for 6-8 h to prepare it.

4. The preparation method of a polyurethane waterproof coating according to claim 2, characterized in that, the preparation method of the dihydroxypropyl octamethyltetrasiloxane in step (2) is as follows: Add 1,1,3,3,5,5,7,7-octamethyltetrasiloxane and allyl alcohol according to a molar ratio of 1:2 to n-hexane which is 6-8 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane, and add chloroplatinic acid which is 0.03-0.05 times the mass of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane. Stir and reflux at 70-80 °C and 500-800 r / min for 4-6 h, and let it stand at 60-70 °C and 1-2 kPa for 3-4 h to prepare it.

5. The preparation method of a polyurethane waterproof coating according to claim 2, characterized in that, the measurement method used to measure the actual remaining amount of isocyanate in the reaction in step (2) is the toluene-di-n-butylamine titration method.

6. The preparation method of a polyurethane waterproof coating according to claim 2, characterized in that, the model of the hydrogen-containing silicone oil in step (3) is MHX-1107.

7. The preparation method of a polyurethane waterproof coating according to claim 2, characterized in that, the coupling agent in step (3) is triethoxysilane.