Room-temperature quick-drying water-based organic silicon resin and preparation method thereof

Abstract

The invention relates to the technical field of organic silicon resin, in particular to normal-temperature quick-drying water-based organic silicon resin and a preparation method thereof. The normal-temperature quick-drying water-based organic silicon resin is prepared from the following components in parts by weight: 0.15 to 0.4 part of methyl trimethoxy silane, 0.05 to 0.2 part of dimethyl dimethoxy silane, 0.3 to 0.6 part of phenyl trimethoxy silane, 0.05 to 0.25 part of diphenyl dimethoxy silane, 0.08 to 0.3 part of 2-(diphenyl hydroxyphosphinite) ethyl triethoxy silane, 0.03 to 0.15 part of 2-acrylamide-2-methylpropanesulfonic acid and the balance of water. And 0.01 to 0.15 part of vinyl trimethoxy silane. 2-(diphenylhydroxyphosphinite) ethyltriethoxysilane is added into a resin molecular chain, the content of the 2-(diphenylhydroxyphosphinite) ethyltriethoxysilane is optimized, and the long-standing problem that quick-drying property and toughness cannot be achieved at the same time in the field of water-based organic silicon resin is solved by utilizing catalytic condensation and proper improvement of crosslinking density.

Description

Technical Field

[0001] This invention relates to the field of organosilicon resin technology, and in particular to a room-temperature fast-drying waterborne organosilicon resin and its preparation method. Background Technology

[0002] With increasingly stringent environmental regulations, waterborne silicone resins, as a core category of low-VOC coatings, are experiencing a surge in demand in the industrial coating sector. However, existing technologies still face significant challenges: achieving a balance between curing speed and mechanical properties is difficult. Traditional waterborne systems generally suffer from long surface drying times (>40 minutes), severely impacting application efficiency; while accelerating curing by adding metal catalysts can lead to heavy metal residues, violating green chemistry principles. Simultaneously, modification methods to increase coating hardness (such as increasing the proportion of rigid monomers) often introduce the risk of brittleness, limiting their application on flexible substrates or in high-impact environments. More importantly, under high temperature and humidity conditions, the resin is prone to surface stickiness, further restricting reliability.

[0003] Current research has attempted to optimize the resin by compounding acrylic monomers or using hyperbranched structures, but has yet to overcome the technical dilemma of "fast drying results in weak toughness, while strong toughness results in slow drying." Developing a waterborne silicone resin that combines efficient curing, high strength and toughness, and environmental adaptability has become a critical issue that the industry urgently needs to address. Summary of the Invention

[0004] This invention provides a room-temperature fast-drying waterborne silicone resin, which is made from the following components in parts by weight: 0.15-0.4 parts of methyltrimethoxysilane, 0.05~0.2 parts of dimethyldimethoxysilane, 0.3-0.6 parts of phenyltrimethoxysilane, 0.05~0.25 parts of diphenyldimethoxysilane, Vinyltrimethoxysilane 0.01~0.15 parts, 0.08~0.3 parts of 2-(diphenylphosphine)ethyltriethoxysilane 0.03 to 0.15 parts of 2-acrylamide-2-methylpropanesulfonic acid.

[0005] The preparation method of the above-mentioned room-temperature fast-drying waterborne organosilicon resin includes the following steps: (1) Under inert gas protection, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, vinyltrimethoxysilane, 2-(diphenylphosphine)ethyltriethoxysilane and dimethylformamide (DMF) are premixed; an acid catalyst is added to adjust the pH of the system to 3.5-4.5, and deionized water is added dropwise at 20-30℃ for hydrolysis for 1.5-3h to obtain silanol prepolymer; an aqueous emulsifier is added and emulsification is carried out at 500-1000 rpm for 10-20min.

[0006] Preferably, the acid catalyst is a 0.05-0.15 M hydrochloric acid solution.

[0007] Preferably, the aqueous emulsifier is HYDROSIL 2627; the mass of the aqueous emulsifier is 3.5~4.5% of the total mass of the silane monomers, and the silane monomers include: monomethyltrimethoxysilane, dimethyldimethoxysilane, monophenyltrimethoxysilane, diphenyldimethoxysilane, vinyltrimethoxysilane, and 2-(diphenylphosphine)ethyltriethoxysilane.

[0008] (2) Under the protection of inert gas, the temperature is raised to 55-65℃, and a solution of dimethylformamide (DMF) containing 2-acrylamide-2-methylpropanesulfonic acid and an initiator are added dropwise at a uniform rate. The dropwise addition time is 0.8-1.2 h, and then the reaction is kept at the temperature for 2.5-3.5 h.

[0009] Preferably, the initiator is benzoyl peroxide (BPO); the amount of initiator is 0.5-2.0% of the total mass of the silane monomers, and the silane monomers include: monomethyltrimethoxysilane, dimethyldimethoxysilane, monophenyltrimethoxysilane, diphenyldimethoxysilane, vinyltrimethoxysilane, and 2-(diphenylphosphine)ethyltriethoxysilane.

[0010] (3) Water-based treatment stage: Cool down to 35-45℃, add alkali solution to neutralize to pH 8.0-9.0; perform high-speed shear emulsification at 10000-15000 rpm for 25-35 min; filter to obtain an aqueous emulsion with a solid content of 38-42%.

[0011] Preferably, the alkaline solution is ammonia.

[0012] Preferably, the inert gas is nitrogen.

[0013] The beneficial effects of this invention are: This invention incorporates 2-(diphenylphosphine)ethyltriethoxysilane into the resin molecular chain and optimizes its content. The P=O groups promote hydrolysis condensation and appropriately increase crosslinking density. Furthermore, the diphenylphosphonate groups act as internal plasticizers and stress dissipators in the crosslinking network, effectively preventing increased brittleness caused by higher crosslinking density. This synergistically achieves a balance between fast drying and toughness, solving the long-standing problem in the field of waterborne silicone resins where fast drying and toughness are mutually exclusive. It shortens surface drying time, improves hardness and adhesion, and emits no VOCs, providing an efficient and environmentally friendly solution for coating. Detailed Implementation

[0014] The present invention will be further described below with reference to the embodiments.

[0015] Example 1

[0016] (1) Under nitrogen protection, 0.40 parts of monomethyltrimethoxysilane, 0.20 parts of dimethyldimethoxysilane, 0.60 parts of monophenyltrimethoxysilane, 0.25 parts of diphenyldimethoxysilane, 0.15 parts of vinyltrimethoxysilane, and 0.30 parts of 2-(diphenylphosphine)ethyltriethoxysilane were premixed with 1.5 parts of dimethylformamide (DMF). The pH of the system was adjusted to 4.5 by adding 0.15 M hydrochloric acid solution as an acid catalyst. Deionized water was added dropwise at 30°C for 3 h to hydrolyze the mixture and obtain a silanol prepolymer. 0.07 parts of waterborne emulsifier HYDROSIL 2627 were added and emulsified at 1000 rpm for 15 min.

[0017] (2) Under nitrogen protection, the temperature was raised to 65°C, and a solution of 0.15 parts of 2-acrylamide-2-methylpropanesulfonic acid and 0.5 parts of DMF and 0.015 parts of BPO were added dropwise at a uniform rate over a period of 1.2 h. The reaction was then kept at the temperature for 3.5 h. (3) Under nitrogen protection, the temperature was lowered to 45°C, and ammonia water was added to neutralize to pH 8.5; high-speed shear emulsification was carried out at 12000 rpm for 35 min; and filtered to obtain an aqueous emulsion with a solid content of 42%.

[0018] Example 2

[0019] (1) Under nitrogen protection, 0.25 parts of monomethyltrimethoxysilane, 0.12 parts of dimethyldimethoxysilane, 0.45 parts of monophenyltrimethoxysilane, 0.15 parts of diphenyldimethoxysilane, 0.08 parts of vinyltrimethoxysilane, and 0.18 parts of 2-(diphenylphosphine)ethyltriethoxysilane were premixed with 1.1 parts of dimethylformamide (DMF); the pH of the system was adjusted to 4 by adding 0.1 M hydrochloric acid solution as an acid catalyst, and deionized water was added dropwise at 25°C for 2 h for hydrolysis to obtain silanol prepolymer; 0.05 parts of aqueous emulsifier HYDROSIL 2627 were added and emulsified at 800 rpm.

[0020] (2) Under nitrogen protection, the temperature was raised to 60°C, and a solution of 0.09 parts of 2-acrylamide-2-methylpropanesulfonic acid and 0.3 parts of dimethylformamide (DMF) and 0.01 parts of initiator benzoyl peroxide (BPO) were added dropwise at a constant rate for 1 hour, followed by a reaction at the temperature for 3 hours. (3) Under nitrogen protection, the temperature was lowered to 40°C, and ammonia water was added to neutralize to pH 8.5; high-speed shear emulsification was carried out at 12000 rpm for 30 min; and filtered to obtain an aqueous emulsion with a solid content of 40% for 10 min.

[0021] Example 3

[0022] (1) Under nitrogen protection, 0.15 parts of monomethyltrimethoxysilane, 0.05 parts of dimethyldimethoxysilane, 0.3 parts of monophenyltrimethoxysilane, 0.05 parts of diphenyldimethoxysilane, 0.01 parts of vinyltrimethoxysilane, 0.08 parts of 2-(diphenylphosphine)ethyltriethoxysilane and 0.8 parts of dimethylformamide (DMF) were premixed; the pH of the system was adjusted to 3.5 by adding 0.05 M hydrochloric acid solution as an acid catalyst, and deionized water was added dropwise at 20 °C for 1.5 h for hydrolysis to obtain silanol prepolymer; 0.03 parts of aqueous emulsifier HYDROSIL 2627 were added and emulsified at 500 rpm for 10 min.

[0023] (2) Under nitrogen protection, the temperature was raised to 55°C, and a solution of 0.03 parts of 2-acrylamide-2-methylpropanesulfonic acid and 0.1 parts of dimethylformamide (DMF) and 0.004 parts of benzoyl peroxide (BPO) initiator were added dropwise at a constant rate over a period of 0.8 h. The reaction was then kept at the temperature for 2.5 h. (3) Under nitrogen protection, the temperature was lowered to 35°C, and ammonia water was added to neutralize to pH 8; high-speed shear emulsification was carried out at 10,000 rpm for 25 min; and filtered to obtain an aqueous emulsion with a solid content of 40%.

[0024] Example 4

[0025] The difference between Example 4 and Example 2 is that the amount of 2-(diphenylphosphine)ethyltriethoxysilane added is adjusted to 0.08 parts, while the rest is the same as in Example 2.

[0026] Example 5

[0027] The difference between Example 5 and Example 2 is that the amount of 2-(diphenylphosphine)ethyltriethoxysilane added is adjusted to 0.28 parts, while the rest is the same as in Example 2.

[0028] Comparative Example 1

[0029] The difference between Comparative Example 1 and Example 2 is that 2-(diphenylphosphine)ethyltriethoxysilane was not added; otherwise, they are the same as in Example 2.

[0030] Comparative Example 2

[0031] The difference between Comparative Example 2 and Example 2 is that the amount of 2-(diphenylphosphine)ethyltriethoxysilane added was adjusted to 0.38 parts, while the rest was the same as in Example 2.

[0032] Example of effect

[0033] The emulsions obtained in the above examples and comparative examples were diluted with pure water to an application viscosity (15s / Ford Cup 4), coated onto cold-rolled steel sheets to a thickness of 50μm, and then tested. The emulsions were allowed to stand at room temperature. Surface drying time was measured every 2 minutes according to the GB / T 1728 finger test, with the endpoint being the absence of fingerprints. Hardness testing was performed after 8 hours at room temperature using the GB / T 6739 pencil hardness test with a 750g load. Adhesion testing was performed after 8 hours at room temperature using the GB / T 9286 cross-cut adhesion test. Curing defects were recorded by finger contact and the cross-cut edge phenomenon was observed. Flexibility testing was conducted according to GB / T 1731.

[0034] The test results are shown in Table 1.

[0035] Table 1 Performance test results of Examples 1-5 and Comparative Examples 1-2

[0036] Comparing the data in Table 1 with those of Comparative Example 3, Comparative Example 1, and Comparative Example 2, it can be seen that the absence of 2-(diphenylphosphine)ethyltriethoxysilane or insufficient addition (<0.18 parts) results in insufficient catalytic condensation, leading to a loose cross-linking network. This manifests as prolonged surface drying time, decreased hardness, surface stickiness, and deteriorated adhesion. Conversely, excessive addition of 2-(diphenylphosphine)ethyltriethoxysilane (>0.28 parts) causes excessive cross-linking, leading to stress concentration, edge brittleness, and decreased adhesion. Although surface drying is extremely fast and hardness is very high, the mechanical properties are unusable. The optimal addition amount of 2-(diphenylphosphine)ethyltriethoxysilane is 0.18-0.28 parts, combining fast drying with good toughness.

[0037] This invention introduces a specific amount of 2-(diphenylphosphine)ethyltriethoxysilane, whose hydrolysis produces silanol groups that can participate in condensation crosslinking, moderately increasing the crosslinking density, thereby accelerating curing and improving hardness. At the same time, the diphenylphosphonate groups in its molecule can form a strong interaction with the substrate through P=O, improving adhesion, and also play a role in internal plasticizing and stress dissipation in the crosslinking network, effectively avoiding the increase in brittleness caused by the increase in crosslinking density, thus synergistically achieving a balance between fast drying and toughness.

[0038] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A room-temperature fast-drying waterborne silicone resin, characterized in that, It is prepared from the following components in parts by weight: 0.15-0.4 parts of methyltrimethoxysilane, 0.05~0.2 parts of dimethyldimethoxysilane, 0.3-0.6 parts of phenyltrimethoxysilane, 0.05~0.25 parts of diphenyldimethoxysilane, 0.08~0.3 parts of 2-(diphenylphosphine)ethyltriethoxysilane 0.03~0.15 parts of 2-acrylamide-2-methylpropanesulfonic acid, Vinyltrimethoxysilane 0.01~0.15 parts.

2. A method for preparing the room-temperature fast-drying waterborne organosilicon resin as described in claim 1, characterized in that, Includes the following steps: (1) Under inert gas protection, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, vinyltrimethoxysilane, 2-(diphenylphosphine)ethyltriethoxysilane and dimethylformamide are premixed; acid catalyst is added to adjust the pH of the system to 3.5-4.5, and deionized water is added dropwise at 20-30℃ for hydrolysis for 1.5-3h to obtain silanol prepolymer, and water-based emulsifier is added and emulsified at 500-1000 rpm for 10-20min; (2) Grafting steps: Under the protection of inert gas, heat to 55-65℃, add dimethylformamide solution containing 2-acrylamide-2-methylpropanesulfonic acid and initiator dropwise at a uniform rate for 0.8-1.2 h, and then keep the reaction at the temperature for 2.5-3.5 h; (3) Water-based treatment stage: Cool down to 35~45℃, add alkali solution to neutralize to pH 8.0-9.0; high-speed shear emulsification, filter, and obtain water-based emulsion with a solid content of 38~42%.

3. The preparation method of the room-temperature fast-drying waterborne organosilicon resin as described in claim 2, characterized in that, The acid catalyst is a 0.05-0.15 M hydrochloric acid solution.

4. The preparation method of the room-temperature fast-drying waterborne organosilicon resin as described in claim 2, characterized in that, The aqueous emulsifier is HYDROSIL 2627.

5. The preparation method of the room-temperature fast-drying waterborne organosilicon resin as described in claim 2, characterized in that, The initiator is benzoyl peroxide.

6. The preparation method of the room-temperature fast-drying waterborne organosilicon resin as described in claim 2, characterized in that, The alkaline solution is ammonia.

7. The preparation method of the room-temperature fast-drying waterborne organosilicon resin as described in claim 2, characterized in that, The inert gas is nitrogen.

8. The preparation method of the room-temperature fast-drying waterborne organosilicon resin as described in claim 2, characterized in that, The high-speed shear emulsification is performed at a rotation speed of 10,000-15,000 rpm for a time of 25-35 minutes.

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