Preparation method and application of organosilicon waterproof coating

Abstract

The invention relates to the technical field of coatings, and discloses a preparation method and application of an organosilicon waterproof coating. The organic silicon waterproof coating is obtained by uniformly stirring and mixing the solvent, the epoxy resin, the pigment filler, the dispersing agent, the defoaming agent, the polyether modified organic silicon polystyrene and the curing agent. According to the invention, polyether modified organosilicon polystyrene is added into the epoxy resin coating, crosslinked polystyrene has very high mechanical strength, a molecular main chain contains flexible siloxane, a side chain contains a polyether chain segment of a three-dimensional branched molecular chain, and the polyether chain segment and an epoxy resin molecular chain form a physical space crosslinking effect; according to the present invention, the main chain organosilicone polystyrene has characteristics of good toughening effect, significantly improved tensile strength, significantly improved elongation at break, significantly improved bending strength and significantly improved impact property, and the main chain organosilicone polystyrene has strong hydrophobicity, such that the hydrophobicity can be improved when the main chain organosilicone polystyrene is added into the epoxy resin coating material, and the water absorption rate can be easily reduced, and the water resistance can be easily improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a preparation method of an organosilicon waterproof coating and application thereof. Background Art

[0002] Epoxy resin coatings have good weather resistance, excellent wear resistance, excellent anti-corrosion performance, and excellent electrical insulation performance. They are widely used in construction materials, roads and bridges, mechanical equipment, electronic and electrical fields. Toughening modification of epoxy resin is a research hotspot. Common toughening agents include nitrile rubber, polysiloxane, polyether and other polymers.

[0003] Polystyrene has good mechanical strength, insulation, waterproof and other properties. It can be made into shell core particles, cross-linked rigid particles, etc., and is widely used as toughening agents, impact modifiers and other additives in coatings, adhesives and other aspects. Patent CN114437300A discloses a preparation method and application of a halogen-free flame retardant toughening agent, wherein an organic silicon monomer, a halogen-free flame retardant, a silane coupling cross-linking agent, etc. are polymerized, and then sequentially polymerized with unsaturated olefins, styrene, acrylonitrile, etc. to obtain a halogen-free flame retardant toughening agent, which can be applied to materials such as polycarbonate, polymethyl methacrylate, and acrylonitrile-butadiene-styrene copolymer. However, the types of polymerized monomers of the halogen-free flame retardant toughening agent are complex, the preparation method is relatively complicated, and the halogen-free flame retardant toughening agent does not improve the water resistance and other properties of the material. Summary of the invention

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

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

[0006] Step S1, add toluene, styrene, 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and organosilicon styrene crosslinking agent into a reaction container, stir to dissolve, introduce nitrogen, add dibenzoyl peroxide, stir to react at 70-85° C. for 8-12 hours, filter, wash with dichloromethane, and dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0007] Step S2, add N,N-dimethylformamide, isocyanate silicone cross-linked polystyrene, polyethylene glycol monomethyl ether, and dibutyltin dilaurate into a reaction container, stir and react at 60-70° C. for 3-5 hours, add ethanol for precipitation, filter, wash with ethanol, and dry to obtain polyether-modified silicone polystyrene.

[0008] Step S3, adding solvent, epoxy resin, pigment, filler, dispersant, defoamer, polyether modified silicone polystyrene into the container, stirring and dispersing, and finally adding curing agent to obtain silicone waterproof coating.

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

[0010] Furthermore, in step S2, the masses of polyethylene glycol monomethyl ether and dibutyltin dilaurate are 5-30% and 0.01-0.07% of the mass of isocyanate silicone cross-linked 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 curing agent, and its mass is 7-30% of the mass of the epoxy resin.

[0013] Furthermore, the preparation method of the organosilicon styrene crosslinker includes: adding toluene, 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, 4-vinylbenzoic acid, and p-toluenesulfonic acid to a reaction container, stirring and reacting at 80-100° C. for 6-10 hours, distilling under reduced pressure, washing with methanol, dissolving the product in ethyl acetate, and purifying by recrystallization to obtain the organosilicon styrene crosslinker. 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 effect of the present invention is as follows: the present invention utilizes 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane and 4-vinylbenzoic acid for graft esterification reaction to obtain an organosilicon styrene crosslinking agent containing two alkenyl groups, and then carries out crosslinking copolymerization reaction with styrene and 3-isopropenyl-α,α-dimethylbenzyl isocyanate to obtain an isocyanate organosilicon crosslinked polystyrene having a three-dimensional crosslinked network structure, and the introduced isocyanate group reacts with the hydroxyl group of polyethylene glycol monomethyl ether to obtain a polyether-modified organosilicon polystyrene having a three-dimensional branched molecular chain.

[0018] The present invention adds polyether-modified silicone polystyrene to the epoxy resin coating. After cross-linking, the polystyrene itself has very high mechanical strength. The main chain of the molecule contains flexible siloxane, and the side chain contains a polyether segment of a three-dimensional branched molecular chain, which forms a physical space cross-linking effect with the epoxy resin molecular chain, can play a good toughening role, and significantly improve the tensile strength, elongation at break, bending strength and impact performance of the epoxy resin. Although the polyether molecular chain of the side chain of the polyether-modified silicone polystyrene is hydrophilic, the silicone polystyrene of the main chain has stronger hydrophobicity. Adding it to the epoxy resin coating can improve its hydrophobicity, which is beneficial to reducing water absorption and improving water resistance. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present 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 into a reaction container, stir and react at 100° C. for 6 h, distill under reduced pressure, wash with methanol, dissolve the product in ethyl acetate, and purify by recrystallization to obtain an organosilicon styrene crosslinker.

[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 an organosilicon styrene crosslinker into a reaction container, stir to dissolve, introduce nitrogen, add 0.054 g of dibenzoyl peroxide, stir to react at 75° C. for 12 h, filter, wash with dichloromethane, and dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0023] (3) Add 700 mL of N,N-dimethylformamide, 50 g of isocyanate silicone cross-linked polystyrene, 6.8 g of polyethylene glycol monomethyl ether 350, and 14 mg of dibutyltin dilaurate into a reaction container, stir and react at 70° C. for 3 h, add ethanol for precipitation, filter, wash with ethanol, and dry to obtain polyether-modified silicone polystyrene.

[0024] (4) Add 1200 mL of n-butanol solvent, 1000 g of epoxy resin E44, 170 g of titanium dioxide pigment, 11 g of dispersant EFKA-AFCONA-5010, 36 g of defoamer DEFOMEX 2063, and 30 g of polyether-modified silicone polystyrene into a container, stir and disperse, and finally add 96 g of diethylenetriamine to obtain a silicone 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 into a reaction container, stir and react at 80° C. for 10 h, distill under reduced pressure, wash with methanol, dissolve the product in ethyl acetate, and purify by recrystallization to obtain an organosilicon styrene crosslinker.

[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 an organosilicon styrene crosslinker into a reaction container, stir to dissolve, introduce nitrogen, add 0.05 g of dibenzoyl peroxide, stir to react at 85° C. for 8 h, filter, wash with dichloromethane, and dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0028] (3) Add 600 mL of N,N-dimethylformamide, 50 g of isocyanate silicone cross-linked polystyrene, 2.5 g of polyethylene glycol monomethyl ether 350, and 5 mg of dibutyltin dilaurate into a reaction container, stir and react at 65° C. for 5 h, add ethanol for precipitation, filter, wash with ethanol, and dry to obtain polyether-modified silicone polystyrene.

[0029] (4) Add 1200 mL of n-butanol solvent, 1000 g of epoxy resin E44, 170 g of titanium dioxide pigment, 11 g of dispersant EFKA-AFCONA-5010, 36 g of defoamer DEFOMEX 2063, and 80 g of polyether-modified silicone polystyrene into a container, stir and disperse, and finally add 70 g of ethylenediamine to obtain a silicone 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 an organosilicon styrene crosslinking agent (prepared according to the method of Example 1) into a reaction container, stir to dissolve, introduce nitrogen, add 0.06 g of dibenzoyl peroxide, stir to react at 75° C. for 12 h, filter, wash with dichloromethane, and dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0032] (2) Add 800 mL of N,N-dimethylformamide, 50 g of isocyanate silicone cross-linked polystyrene, 15 g of polyethylene glycol monomethyl ether 350, and 35 mg of dibutyltin dilaurate into a reaction container, stir and react at 70° C. for 3 h, add ethanol for precipitation, filter, wash with ethanol, and dry to obtain polyether-modified silicone polystyrene.

[0033] (3) Add 1200 mL of n-butanol solvent, 1000 g of epoxy resin E44, 170 g of titanium dioxide pigment, 11 g of dispersant EFKA-AFCONA-5010, 36 g of defoamer DEFOMEX 2063, and 140 g of polyether-modified silicone polystyrene into a container, stir and disperse, and finally add 300 g of 4,4-diaminodiphenyl sulfone to obtain a silicone 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 an organosilicon styrene crosslinker (prepared according to the method of Example 1) into a reaction container, stir to dissolve, introduce nitrogen, add 0.06 g of dibenzoyl peroxide, stir to react at 70° C. for 12 h, filter, wash with dichloromethane, and dry to obtain isocyanate organosilicon crosslinked polystyrene.

[0036] (2) Add 800 mL of N,N-dimethylformamide, 50 g of isocyanate silicone cross-linked polystyrene, 11.4 g of polyethylene glycol monomethyl ether 350, and 27 mg of dibutyltin dilaurate into a reaction container, stir and react at 60° C. for 5 h, add ethanol for precipitation, filter, wash with ethanol, and dry to obtain polyether-modified silicone polystyrene.

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

[0038] Comparative Example 1

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

[0040] Comparative Example 2

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

[0042] Comparative Example 3

[0043] (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 benzoyl peroxide to a reaction container, stir to dissolve, introduce nitrogen, add 0.054 g of dibenzoyl peroxide, stir to react at 75°C for 12 h, filter, wash with dichloromethane, and dry to obtain isocyanate polystyrene.

[0044] (2) Add 700 mL of N,N-dimethylformamide, 50 g of isocyanate polystyrene, 6.8 g of polyethylene glycol monomethyl ether 350, and 14 mg of dibutyltin dilaurate into a reaction container, stir and react at 70° C. for 3 h, add ethanol for precipitation, filter, wash with ethanol, and dry to obtain polyether-modified polystyrene.

[0045] (3) Add 1200 mL of n-butanol solvent, 1000 g of epoxy resin E44, 170 g of titanium dioxide pigment, 11 g of dispersant EFKA-AFCONA-5010, 36 g of defoamer DEFOMEX 2063, and 30 g of polyether-modified polystyrene into a container, stir and disperse, and finally add 96 g of diethylenetriamine to obtain a 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 cross-linking agent divinylbenzene into a reaction container, stir to dissolve, introduce nitrogen, add 0.054 g of dibenzoyl peroxide, stir to react at 75° C. for 12 h, filter, wash with dichloromethane, and dry to obtain isocyanate cross-linked polystyrene.

[0048] (2) Add 700 mL of N,N-dimethylformamide, 50 g of isocyanate cross-linked polystyrene, 6.8 g of polyethylene glycol monomethyl ether 350, and 14 mg of dibutyltin dilaurate into a reaction container, stir and react at 70° C. for 3 h, add ethanol for precipitation, filter, wash with ethanol, and dry to obtain polyether-modified polystyrene.

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

[0050] Pour the coating into the mold and heat cure it at 100°C for 3 hours and at 140°C for 5 hours to make a casting sample. The mechanical properties are tested according to the GB / T 2567-2021 method.

[0051] Weigh the casting, soak it in water for 48-72 hours, take out the casting, remove the surface water with filter paper, weigh it, 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 test

[0053]

[0054] Compared with Examples 1-4, Comparative Example 1 does not add polyether-modified organosilicon polystyrene, the isocyanate organosilicon cross-linked polystyrene added in Comparative Example 2 does not contain a flexible polyether molecular chain, and the isocyanate polystyrene and polyether-modified polystyrene obtained in Comparative Example 3 do not add an organosilicon cross-linking agent when preparing isocyanate polystyrene, and do not contain a three-dimensional cross-linked structure, nor a flexible and water-resistant siloxane structure, and Comparative Example 4 uses divinylbenzene instead of an organosilicon cross-linking agent, and the isocyanate cross-linked polystyrene and polyether-modified polystyrene obtained do not contain a flexible and water-resistant siloxane structure. As a result, the tensile strength, elongation at break, bending strength and impact strength of Comparative Examples 1-4 are lower than those of Examples 1-4, and the water absorption of Comparative Examples 1, 3, and 4 is relatively large, and the water resistance is poor.

[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 in the protection scope of the present invention.

Claims

1. A method for preparing an organosilicon waterproof coating, characterized in that: The preparation method comprises the following steps: Step S1, adding toluene, styrene, 3-isopropenyl-α,α-dimethylbenzyl isocyanate, and an organosilicon styrene crosslinking agent into a reaction container, stirring to dissolve, introducing nitrogen, adding dibenzoyl peroxide, stirring to react, filtering, washing, and drying to obtain isocyanate organosilicon crosslinked polystyrene; Step S2, adding N,N-dimethylformamide, isocyanate organosilicon cross-linked polystyrene, polyethylene glycol monomethyl ether, and dibutyltin dilaurate into a reaction container, stirring for reaction, adding ethanol for precipitation, filtering, washing, and drying to obtain polyether-modified organosilicon polystyrene; Step S3, adding solvent, epoxy resin, pigment, filler, dispersant, defoamer, polyether modified silicone polystyrene into the container, stirring and dispersing, and finally adding curing agent to obtain silicone waterproof coating.

2. The method for preparing the organic silicon waterproof coating according to claim 1, characterized in that: In the step S1, the masses of 3-isopropenyl-α,α-dimethylbenzyl isocyanate, the organosilicon styrene crosslinking agent, and dibenzoyl peroxide are 1.5-4%, 3-10%, and 0.5-0.6% of the mass of styrene, respectively.

3. The method for preparing the organic silicon waterproof coating according to claim 1, characterized in that: In the step S1, the reaction is carried out at 70-85° C. for 8-12 hours.

4. The method for preparing the organic silicon waterproof coating according to claim 1, characterized in that: In the step S2, the masses of polyethylene glycol monomethyl ether and dibutyltin dilaurate are 5-30% and 0.01-0.07% of the mass of isocyanate silicone cross-linked polystyrene, respectively.

5. The method for preparing the organic silicon waterproof coating according to claim 1, characterized in that: In the step S2, the reaction is carried out at 60-70° C. for 3-5 hours.

6. The method for preparing the organic silicon waterproof coating according to claim 1, characterized in that: In the step S3, the mass of the polyether-modified silicone polystyrene is 3-20% of the mass of the epoxy resin.

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

8. The method for preparing the organic silicon waterproof coating according to claim 1, characterized in that: The preparation method of the organosilicon styrene crosslinking agent comprises: adding toluene, 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, 4-vinylbenzoic acid and p-toluenesulfonic acid into a reaction container, stirring and reacting at 80-100° C. for 6-10 hours, performing reduced pressure distillation, washing and recrystallization purification to obtain the organosilicon styrene crosslinking agent.

9. The method for preparing the organic silicon waterproof coating according to claim 7, characterized in that: The masses 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.

10. Use of the organosilicon waterproof coating obtained by the preparation method according to any one of claims 1 to 9 in building roofs and facades.

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