Preparation method of silicone waterproof coating and application thereof

Abstract

The application relates to the technical field of paint, and discloses a preparation method and application of silicone waterproof paint; solvent, epoxy resin, pigment and filler, dispersant, defoaming agent, polyether modified organosilicon polystyrene and curing agent are stirred and uniformly mixed to obtain the silicone waterproof paint. The polyether modified organosilicon polystyrene is added into the epoxy resin paint, the polystyrene has high mechanical strength after cross-linking, the main chain of the molecule contains flexible siloxane, the side chain contains a three-dimensional branched molecular chain polyether segment, and the epoxy resin molecular chain forms a physical space cross-linking effect, so that good toughening effect can be achieved, the tensile strength, elongation at break, bending strength and impact performance of the epoxy resin are significantly improved, meanwhile, the main chain organosilicon polystyrene has stronger hydrophobicity, the hydrophobicity of the epoxy resin paint can be improved by adding the organosilicon polystyrene, and the water absorption rate is reduced and the water resistance is improved.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a method for preparing an organosilicon waterproof coating and its application. Background Technology

[0002] Epoxy resin coatings possess excellent weather resistance, abrasion resistance, corrosion resistance, and electrical insulation properties, making them widely used in building materials, road and bridge construction, machinery, and electronics. Toughening modification of epoxy resins is a hot research topic. Common toughening agents include nitrile rubber, polysiloxanes, and polyethers.

[0003] Polystyrene possesses excellent mechanical strength, insulation, and waterproof properties. It can be formulated into core-shell particles and cross-linked rigid particles, serving as a toughening agent, impact modifier, and other additives with wide applications in coatings and adhesives. Patent CN114437300A discloses a method for preparing a halogen-free flame-retardant toughening agent and its application. This method involves polymerizing organosilicon monomers, a halogen-free flame retardant, and a silane coupling cross-linking agent, followed by sequential polymerization with unsaturated olefins, styrene, and acrylonitrile to obtain a halogen-free flame-retardant toughening agent that can be applied to materials such as polycarbonate, polymethyl methacrylate, and acrylonitrile-butadiene-styrene copolymers. However, this halogen-free flame-retardant toughening agent involves a wide variety of monomers, a complex preparation method, and does not improve the water resistance or other properties of the materials. Summary of the Invention

[0004] This invention solves the problems of poor toughness and low strength of epoxy resin.

[0005] The technical solution provided by this invention is: a method for preparing an organosilicon waterproof coating, comprising the following steps:

[0006] Step S1: Add toluene, styrene, 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and organosilicon styrene crosslinking agent to the reaction vessel, stir to dissolve, introduce nitrogen gas, add benzoyl peroxide, stir and react at 70-85℃ for 8-12 hours, filter, wash with dichloromethane, dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0007] Step S2: Add N,N-dimethylformamide, isocyanate organosilicon crosslinked polystyrene, polyethylene glycol monomethyl ether, and dibutyltin dilaurate to the reaction vessel. Stir and react at 60-70℃ for 3-5 hours. Add ethanol to precipitate the polyether-modified organosilicon polystyrene. After filtration, wash with ethanol and dry to obtain polyether-modified organosilicon polystyrene.

[0008] Step S3: Add solvent, epoxy resin, pigments and fillers, dispersant, defoamer, and polyether-modified silicone polystyrene to the container, stir and disperse, and finally add curing agent to obtain silicone waterproof coating.

[0009] Furthermore, in S1, the mass of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, organosilicon styrene crosslinking agent, and benzoyl peroxide are 1.5-4%, 3-10%, and 0.5-0.6% of the mass of styrene, respectively.

[0010] Furthermore, in step S2, the mass of polyethylene glycol monomethyl ether and dibutyltin dilaurate are 5-30% and 0.01-0.07% of the mass of isocyanate organosilicon crosslinked polystyrene, respectively.

[0011] Furthermore, in step S3, the mass of the polyether-modified silicone polystyrene is 3-20% of the mass of the epoxy resin.

[0012] Furthermore, in step S3, the curing agent is an amine-based curing agent, and its mass is 7-30% of the mass of the epoxy resin.

[0013] Furthermore, the preparation method of the organosilicon styrene crosslinking agent includes: adding toluene, 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, 4-vinylbenzoic acid, and p-toluenesulfonic acid to a reaction vessel, stirring the reaction at 80-100℃ for 6-10 h, followed by vacuum distillation, washing with methanol, dissolving the product in ethyl acetate, recrystallizing and purifying to obtain the organosilicon styrene crosslinking agent. The reaction formula is as follows:

[0014] .

[0015] Furthermore, the masses of 4-vinylbenzoic acid and p-toluenesulfonic acid are 118-142% and 10-14% of the mass of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, respectively.

[0016] Furthermore, silicone waterproof coatings are used in building roofs and facades.

[0017] The technical advantages of this invention are as follows: This invention utilizes a graft esterification reaction of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane and 4-vinylbenzoic acid to obtain an organosilicon styrene crosslinking agent containing two alkenyl groups. Then, it undergoes a crosslinking copolymerization reaction with styrene and 3-isopropenyl-α,α-dimethylbenzyl isocyanate to obtain isocyanate organosilicon crosslinked polystyrene with a three-dimensional crosslinked network structure. The introduced isocyanate groups then react with the hydroxyl groups of polyethylene glycol monomethyl ether to obtain polyether-modified organosilicon polystyrene with three-dimensional branched molecular chains.

[0018] This invention introduces polyether-modified organosilicon polystyrene into epoxy resin coatings. After crosslinking, the polystyrene itself possesses high mechanical strength, and its main molecular chain contains flexible siloxanes, while its side chains contain polyether segments with three-dimensional branched molecular chains. These segments form a physical spatial crosslinking effect with the epoxy resin molecular chains, resulting in excellent toughening properties. This significantly improves the tensile strength, elongation at break, flexural strength, and impact resistance of the epoxy resin. Furthermore, although the polyether molecular chains of the polyether-modified organosilicon polystyrene side chains are hydrophilic, the main organosilicon polystyrene chain is more hydrophobic. Adding this to the epoxy resin coating enhances its hydrophobicity, which helps reduce water absorption and improve water resistance. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] Example 1

[0021] (1) Add 80 mL of toluene, 5 g of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, 7.1 g of 4-vinylbenzoic acid, and 0.5 g of p-toluenesulfonic acid to the reaction vessel. Stir the reaction at 100 °C for 6 h, distill under reduced pressure, wash with methanol, dissolve the product in ethyl acetate, recrystallize and purify to obtain organosilicon styrene crosslinking agent.

[0022] (2) Add 20 mL of toluene, 10 g of styrene, 0.23 g of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and 0.6 g of organosilicon styrene crosslinking agent to the reaction vessel, stir to dissolve, introduce nitrogen gas, add 0.054 g of benzoyl peroxide, stir and react at 75 °C for 12 h, filter, wash with dichloromethane, dry, and obtain isocyanate organosilicon crosslinked polystyrene.

[0023] (3) Add 700mL of N,N-dimethylformamide, 50g of isocyanate organosilicon crosslinked polystyrene, 6.8g of polyethylene glycol monomethyl ether 350, and 14mg of dibutyltin dilaurate to the reaction vessel. Stir the reaction at 70℃ for 3h, add ethanol to precipitate, filter, wash with ethanol, and dry to obtain polyether modified organosilicon polystyrene.

[0024] (4) Add 1200mL n-butanol solvent, 1000g epoxy resin E44, 170g titanium dioxide pigment and filler, 11g dispersant EFKA-AFCONA-5010, 36g defoamer DEFOMEX 2063, and 30g polyether modified organosilicon polystyrene to the container, stir and disperse, and finally add 96g diethylenetriamine to obtain organosilicon waterproof coating.

[0025] Example 2

[0026] (1) Add 70 mL of toluene, 5 g of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, 5.9 g of 4-vinylbenzoic acid, and 0.7 g of p-toluenesulfonic acid to the reaction vessel. Stir the reaction at 80 °C for 10 h, distill under reduced pressure, wash with methanol, dissolve the product in ethyl acetate, recrystallize and purify to obtain organosilicon styrene crosslinking agent.

[0027] (2) Add 15 mL of toluene, 10 g of styrene, 0.15 g of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and 0.3 g of organosilicon styrene crosslinking agent to the reaction vessel, stir to dissolve, introduce nitrogen gas, add 0.05 g of benzoyl peroxide, stir and react at 85 °C for 8 h, filter, wash with dichloromethane, dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0028] (3) Add 600mL of N,N-dimethylformamide, 50g of isocyanate organosilicon crosslinked polystyrene, 2.5g of polyethylene glycol monomethyl ether 350, and 5mg of dibutyltin dilaurate to the reaction vessel. Stir the reaction at 65℃ for 5h, add ethanol to precipitate, filter, wash with ethanol, and dry to obtain polyether modified organosilicon polystyrene.

[0029] (4) Add 1200mL n-butanol solvent, 1000g epoxy resin E44, 170g titanium dioxide pigment and filler, 11g dispersant EFKA-AFCONA-5010, 36g defoamer DEFOMEX 2063, and 80g polyether modified organosilicon polystyrene to the container, stir and disperse, and finally add 70g ethylenediamine to obtain organosilicon waterproof coating.

[0030] Example 3

[0031] (1) Add 20 mL of toluene, 10 g of styrene, 0.4 g of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and 1 g of organosilicon styrene crosslinking agent (prepared according to the method of Example 1) to the reaction vessel, stir to dissolve, introduce nitrogen gas, add 0.06 g of benzoyl peroxide, stir and react at 75 °C for 12 h, filter, wash with dichloromethane, dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0032] (2) Add 800mL of N,N-dimethylformamide, 50g of isocyanate organosilicon crosslinked polystyrene, 15g of polyethylene glycol monomethyl ether 350, and 35mg of dibutyltin dilaurate to the reaction vessel. Stir the reaction at 70℃ for 3h, add ethanol to precipitate, filter, wash with ethanol, and dry to obtain polyether modified organosilicon polystyrene.

[0033] (3) Add 1200mL n-butanol solvent, 1000g epoxy resin E44, 170g pigment and filler titanium dioxide, 11g dispersant EFKA-AFCONA-5010, 36g defoamer Ningbo DEFOMEX 2063, and 140g polyether modified organosilicon polystyrene to the container, stir and disperse, and finally add 300g 4,4-diaminodiphenyl sulfone to obtain organosilicon waterproof coating.

[0034] Example 4

[0035] (1) Add 20 mL of toluene, 10 g of styrene, 0.32 g of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and 0.8 g of organosilicon styrene crosslinking agent (prepared according to the method of Example 1) to the reaction vessel, stir to dissolve, introduce nitrogen gas, add 0.06 g of benzoyl peroxide, stir and react at 70 °C for 12 h, filter, wash with dichloromethane, dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0036] (2) Add 800mL of N,N-dimethylformamide, 50g of isocyanate organosilicon crosslinked polystyrene, 11.4g of polyethylene glycol monomethyl ether 350, and 27mg of dibutyltin dilaurate to the reaction vessel. Stir the reaction at 60℃ for 5h, add ethanol to precipitate, filter, wash with ethanol, and dry to obtain polyether modified organosilicon polystyrene.

[0037] (3) Add 1200mL n-butanol solvent, 1000g epoxy resin E44, 170g pigment and filler titanium dioxide, 11g dispersant EFKA-AFCONA-5010, 36g defoamer Ningbo DEFOMEX 2063, and 200g polyether modified organosilicon polystyrene to the container, stir and disperse, and finally add 96g diethylenetriamine to obtain organosilicon waterproof coating.

[0038] Comparative Example 1

[0039] (1) Add 1200mL n-butanol solvent, 1000g epoxy resin E44, 170g pigment and filler titanium dioxide, 11g dispersant EFKA-AFCONA-5010, 36g defoamer Ningbo DEFOMEX 2063 to the container, stir and disperse, and finally add 96g diethylenetriamine to obtain the coating.

[0040] Comparative Example 2

[0041] (1) Add 1200mL n-butanol solvent, 1000g epoxy resin E44, 170g pigment and filler titanium dioxide, 11g dispersant EFKA-AFCONA-5010, 36g defoamer DEFOMEX 2063, and 30g isocyanate silicone crosslinked polystyrene (prepared according to the method of Example 1) to the container, stir and disperse, and finally add 96g diethylenetriamine to obtain silicone waterproof coating.

[0042] Comparative Example 3

[0043] (1) Add 20 mL of toluene, 10 g of styrene, and 0.23 g of 3-isopropenyl-α,α-dimethylbenzyl isocyanate to the reaction vessel, stir to dissolve, introduce nitrogen gas, add 0.054 g of benzoyl peroxide, stir and react at 75 °C for 12 h, filter, wash with dichloromethane, dry to obtain isocyanate polystyrene.

[0044] (2) Add 700mL of N,N-dimethylformamide, 50g of polystyrene isocyanate, 6.8g of polyethylene glycol monomethyl ether 350, and 14mg of dibutyltin dilaurate to the reaction vessel. Stir the reaction at 70℃ for 3h, add ethanol to precipitate, filter, wash with ethanol, and dry to obtain polyether modified polystyrene.

[0045] (3) Add 1200mL n-butanol solvent, 1000g epoxy resin E44, 170g titanium dioxide pigment and filler, 11g dispersant EFKA-AFCONA-5010, 36g defoamer DEFOMEX 2063, and 30g polyether modified polystyrene to the container, stir and disperse, and finally add 96g diethylenetriamine to obtain the coating.

[0046] Comparative Example 4

[0047] (1) Add 20 mL of toluene, 10 g of styrene, 0.23 g of 3-isopropenyl-α,α-dimethylbenzyl isocyanate and 0.6 g of crosslinking agent divinylbenzene to the reaction vessel, stir to dissolve, introduce nitrogen gas, add 0.054 g of benzoyl peroxide, stir to react at 75 °C for 12 h, filter, wash with dichloromethane, dry to obtain isocyanate crosslinked polystyrene.

[0048] (2) Add 700mL of N,N-dimethylformamide, 50g of cross-linked polystyrene isocyanate, 6.8g of polyethylene glycol monomethyl ether 350, and 14mg of dibutyltin dilaurate to the reaction vessel. Stir the reaction at 70℃ for 3h, add ethanol to precipitate, filter, wash with ethanol, and dry to obtain polyether modified polystyrene.

[0049] (3) Add 1200mL n-butanol solvent, 1000g epoxy resin E44, 170g pigment and filler titanium dioxide, 11g dispersant EFKA-AFCONA-5010, 36g defoamer DEFOMEX 2063, and 30g polyether modified polystyrene to the container, stir and disperse, and finally add 96g diethylenetriamine to obtain the organosilicon waterproof coating.

[0050] The coating was poured into a mold and then heat-cured at 100℃ for 3 hours and at 140℃ for 5 hours to form a casting sample. The mechanical properties were tested according to GB / T 2567-2021.

[0051] Weigh the casting, immerse it in water for 48-72 hours, remove the casting, remove the surface water with filter paper, weigh it again, and calculate the water absorption rate. Water absorption rate = (mass after water absorption - mass before water absorption) ÷ mass before water absorption × 100%. The test results are shown in Table 1.

[0052] Table 1 Coating Performance Tests

[0053]

[0054] Compared to Examples 1-4, Comparative Example 1 did not include polyether-modified silicone polystyrene; Comparative Example 2 included isocyanate-modified silicone crosslinked polystyrene that did not contain flexible polyether molecular chains; Comparative Example 3 prepared isocyanate polystyrene without adding silicone styrene crosslinking agent; the resulting isocyanate polystyrene and polyether-modified polystyrene did not contain three-dimensional crosslinked structures, nor flexible and water-resistant siloxane structures; Comparative Example 4 used divinylbenzene instead of silicone styrene crosslinking agent; the resulting isocyanate crosslinked polystyrene and polyether-modified polystyrene did not contain flexible and water-resistant siloxane structures. This resulted in the tensile strength, elongation at break, flexural strength, and impact strength of Comparative Examples 1-4 being lower than those of Examples 1-4, and Comparative Examples 1, 3, and 4 having higher water absorption rates and poor water resistance.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an organosilicon waterproof coating, characterized in that, The preparation method includes the following steps: Step S1: Add toluene, styrene, 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and organosilicon styrene crosslinking agent to the reaction vessel, stir to dissolve, introduce nitrogen gas, add benzoyl peroxide, stir to react, filter, wash, and dry to obtain isocyanate organosilicon crosslinked polystyrene. Step S2: Add N,N-dimethylformamide, isocyanate organosilicon crosslinked polystyrene, polyethylene glycol monomethyl ether, and dibutyltin dilaurate to the reaction vessel. After stirring and reacting, add ethanol to precipitate the polyether-modified organosilicon polystyrene. After filtration, wash and dry to obtain polyether-modified organosilicon polystyrene. Step S3: Add solvent, epoxy resin, pigments and fillers, dispersant, defoamer, and polyether-modified silicone polystyrene to the container, stir and disperse, and finally add curing agent to obtain silicone waterproof coating. In step S1, the mass percentages of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, organosilicon styrene crosslinking agent, and benzoyl peroxide are 1.5-4%, 3-10%, and 0.5-0.6% of the mass of styrene, respectively. In step S3, the mass of the polyether-modified silicone polystyrene is 3-20% of the mass of the epoxy resin; The preparation method of the organosilicon styrene crosslinking agent includes: adding toluene, 1,3-di(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, 4-vinylbenzoic acid, and p-toluenesulfonic acid to a reaction vessel, stirring and reacting at 80-100℃ for 6-10 h, followed by vacuum distillation, washing, recrystallization and purification to obtain the organosilicon styrene crosslinking agent.

2. The method for preparing the organosilicon waterproof coating according to claim 1, characterized in that, In step S1, the reaction is carried out at 70-85℃ for 8-12 hours.

3. The method for preparing the organosilicon waterproof coating according to claim 1, characterized in that, In step S2, the mass of polyethylene glycol monomethyl ether and dibutyltin dilaurate is 5-30% and 0.01-0.07% of the mass of isocyanate organosilicon crosslinked polystyrene, respectively.

4. The method for preparing the organosilicon waterproof coating according to claim 1, characterized in that, In step S2, the reaction is carried out at 60-70℃ for 3-5 hours.

5. The method for preparing the organosilicon waterproof coating according to claim 1, characterized in that, In step S3, the curing agent is an amine-based curing agent, and its mass is 7-30% of the mass of the epoxy resin.

6. The method for preparing the organosilicon waterproof coating according to claim 1, characterized in that, The mass of the 4-vinylbenzoic acid and p-toluenesulfonic acid are 118-142% and 10-14% of the mass of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, respectively.

7. The application of an organosilicon waterproof coating obtained by the preparation method according to any one of claims 1-6 on building roofs or facades.

Images