Aqueous base material wetting agent based on polyether-modified siloxane and a method for its preparation

Abstract

This invention relates to the field of wetting agent technology and discloses an aqueous substrate wetting agent based on polyether-modified siloxane and its preparation method. The invention involves an amidation polymerization reaction of diaminopropyl polysiloxane and fumarate chloride, followed by a Michael addition reaction with the amino group of alanine-based polyethylene glycol monomethyl ether to obtain an aqueous substrate wetting agent based on polyether-modified siloxane. Introducing a large number of hydrophilic polyether molecular chains and imino groups into the side chains of the polysiloxane improves the hydrophilicity of the wetting agent, giving it higher amphiphilicity, thereby effectively reducing surface tension and improving wetting performance. In practical applications, acrylic resin coatings with the added wetting agent not only effectively avoid pinholes, but the surface tension is significantly reduced, as can be seen from the coating surface. The coating film exhibits excellent leveling properties, high gloss, and no pinholes on the entire surface, indicating that the wetting agent has excellent leveling and stability.

Description

Technical Field

[0001] This invention relates to the field of wetting agent technology, specifically to an aqueous substrate wetting agent based on polyether-modified siloxane and its preparation method. Background Technology

[0002] Wetting agents are mainly used in coatings, inks and other fields. By adding wetting agents, surface tension is reduced and adhesion and leveling are enhanced, thereby improving the spreading ability of coatings and inks on the substrate surface. This solves problems such as insufficient adhesion, pinholes and poor leveling in actual construction. Wetting agents are mainly anionic, cationic, polyoxyethylene ether, siloxane and other types. Among them, polyether modified silicone oil has ultra-low surface tension characteristics and is suitable for special substrates such as plastics, metals and low surface energy materials.

[0003] Traditional polyether-modified silicone oils are mainly prepared by hydrosilylation reaction of hydrogen-containing silicone oil with allyl polyether under the action of platinum catalysts such as chloroplatinic acid and castor oil. However, the hydrogen content of the hydrogen-containing silicone oil is not high, which affects the grafting rate of allyl polyether and is not conducive to improving the amphiphilicity, surface activity and wettability of the polyether-modified silicone oil wetting agent. Summary of the Invention

[0004] Technical problem solved: In view of the shortcomings of the prior art, the present invention provides an aqueous substrate wetting agent based on polyether modified siloxane, which solves the problems of high surface tension and low wettability and anti-cratering ability of polyether modified siloxane wetting agents.

[0005] The technical solution of this invention: A method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane: (1) Polyethylene glycol monomethyl ether, β-alanine, and p-toluenesulfonic acid were added to toluene, stirred, and distilled under reduced pressure. The product was added to a saturated sodium chloride solution, extracted with dichloromethane, and the organic phase was distilled under reduced pressure and dried to obtain alanine-based polyethylene glycol monomethyl ether. The reaction formula is: .

[0006] (2) Add diaminopropyl polysiloxane and triethylamine to N,N-dimethylformamide, add fumarate chloride dropwise in an ice-water bath, stir and react, distill under reduced pressure and add the product to water, stir and let stand to separate the layers, separate and remove the aqueous phase, dry the oil phase to obtain the wetting agent precursor.

[0007] (3) Add a wetting agent precursor and alanine-based polyethylene glycol monomethyl ether to N,N-dimethylformamide, stir and react, distill under reduced pressure, add saturated sodium carbonate aqueous solution, stir and allow to stand for separation, separate and remove the aqueous phase, and dry the oil phase to obtain an aqueous substrate wetting agent based on polyether-modified siloxane. The reaction formula is: .

[0008] Furthermore, in (1), the mass ratio of polyethylene glycol monomethyl ether, β-alanine, and p-toluenesulfonic acid is 100g:(7.8-8.6):(0.8-1).

[0009] Furthermore, in the preparation method of alanine-based polyethylene glycol monomethyl ether in (1), the reaction temperature is 100-115℃ and the reaction time is 6-9h.

[0010] Furthermore, in (2), the ratio of diaminopropyl polysiloxane, triethylamine, and fumarate is 100g: (7.6-8.2)g: (10-13)g.

[0011] Furthermore, in (2), the reaction temperature is 20-40℃ and the reaction time is 9-15h.

[0012] Furthermore, in (3), the reaction temperature is 40-70℃ and the reaction time is 12-18h.

[0013] Furthermore, in (3), the ratio of wetting agent precursor to alanine-based polyethylene glycol monomethyl ether is 100g: (15-40)g.

[0014] The beneficial technical effects of this invention are as follows: Traditional polyether-modified silicone oils are prepared by hydrosilylation reaction of hydrogen-containing silicone oil and allyl polyether. However, due to the low silicon content of the raw material hydrogen-containing silicone oil, there are fewer grafted polyether molecular chains, which affects amphiphilicity and surface activity, and is not conducive to reducing surface tension and wettability. This invention involves an amidation polymerization reaction of bi-terminated aminopropyl polysiloxane and fumarate chloride, followed by a Michael addition reaction with the amino group of alanine-based polyethylene glycol monomethyl ether, to obtain an aqueous substrate wetting agent based on polyether-modified silicone. The introduction of a large number of hydrophilic polyether molecular chains and imino groups into the side chains of the polysiloxane improves the hydrophilicity of the wetting agent, giving it higher amphiphilicity, thereby effectively reducing surface tension and improving wetting effect. Furthermore, it eliminates the need for a precious metal platinum catalyst, resulting in lower costs.

[0015] The wetting and dispersing agent of this invention contains a large number of ester groups and amide bonds. The ester groups have excellent compatibility with acrylic resins, and the amide bonds can form hydrogen bonds with the urethane groups of polyurethane resins, resulting in better compatibility and dispersibility between the wetting agent and both acrylic and polyurethane resins, and improved wetting, dispersing, and viscosity-reducing properties. In practical applications, acrylic resin coatings with the added wetting agent not only effectively avoid pinholes, but also significantly reduce surface tension, as seen on the coating surface, with the coating penetrating the blank formulation to approximately 0.5 cm. The coating film with the added wetting agent exhibits excellent leveling properties, high gloss, and no pinholes on the entire surface, indicating that the wetting agent possesses excellent leveling properties and stability. Attached Figure Description

[0016] Figure 1 It is a picture of an acrylic resin coating film.

[0017] Figure 2 This is a diagram showing the leveling effect of an acrylic resin coating film. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 (1) Add 5g polyethylene glycol monomethyl ether (model MPEG1200, average molecular weight about 1200), 0.43g β-alanine and 0.046g p-toluenesulfonic acid to 8mL toluene, heat to 110℃, stir and reflux for 9h. Remove the generated water with a water separator during the reaction, distill under reduced pressure, add the product to saturated sodium chloride solution, extract with dichloromethane, distill under reduced pressure on the organic phase, and dry to obtain alanine-based polyethylene glycol monomethyl ether.

[0020] (2) Add 5g of diaminopropyl polysiloxane (model Guangzhou Xuxiang Chemical CM-226) and 0.38g of triethylamine to 80mL of N,N-dimethylformamide. Add 0.54g of fumarate chloride dropwise in an ice-water bath. Stir the reaction at 25℃ for 12h. After vacuum distillation, add the product to water, stir, let stand to separate the layers, separate and remove the aqueous phase, and dry the oil phase to obtain the wetting agent precursor.

[0021] (3) Add 10g of wetting agent precursor and 1.5g of alanine-based polyethylene glycol monomethyl ether to 120mL of N,N-dimethylformamide, heat to 70℃, stir and react for 12h, distill under reduced pressure, add saturated sodium carbonate aqueous solution, stir and let stand to separate the layers, separate and remove the aqueous phase, dry the oil phase to obtain a water-based substrate wetting agent based on polyether modified siloxane.

[0022] Example 2 (1) Add 5g polyethylene glycol monomethyl ether, 0.39g β-alanine and 0.05g p-toluenesulfonic acid to 10mL toluene, heat to 100℃, stir and reflux for 9h. Remove the generated water with a water separator during the reaction, distill under reduced pressure, add the product to saturated sodium chloride solution, extract with dichloromethane, distill under reduced pressure on the organic phase, and dry to obtain alanine-based polyethylene glycol monomethyl ether.

[0023] (2) Add 5g of diaminopropyl polysiloxane and 0.38g of triethylamine to 60mL of N,N-dimethylformamide, add 0.65g of fumarate chloride dropwise in an ice-water bath, stir and react at 40℃ for 9h, add the product to water after vacuum distillation, stir and let stand to separate the layers, remove the aqueous phase, dry the oil phase to obtain the wetting agent precursor.

[0024] (3) Add 10g of wetting agent precursor and 3g of alanine-based polyethylene glycol monomethyl ether to 120mL of N,N-dimethylformamide, heat to 50℃, stir and react for 12h, distill under reduced pressure, add saturated sodium carbonate aqueous solution, stir and let stand to separate the layers, separate and remove the aqueous phase, and dry the oil phase to obtain a water-based substrate wetting agent based on polyether modified siloxane.

[0025] Example 3 (1) Add 5g polyethylene glycol monomethyl ether, 0.42g β-alanine and 0.04g p-toluenesulfonic acid to 10mL toluene, heat to 115℃, stir and reflux for 6h, remove the generated water with a water separator during the reaction, distill under reduced pressure, add the product to saturated sodium chloride solution, extract with dichloromethane, distill under reduced pressure on the organic phase, and dry to obtain alanine-based polyethylene glycol monomethyl ether.

[0026] (2) Add 5g of diaminopropyl polysiloxane and 0.41g of triethylamine to 80mL of N,N-dimethylformamide, add 0.5g of fumarate chloride dropwise in an ice-water bath, stir and react at 20℃ for 15h, add the product to water after vacuum distillation, stir and let stand to separate the layers, remove the aqueous phase, dry the oil phase to obtain the wetting agent precursor.

[0027] (3) Add 10g of wetting agent precursor and 4g of alanine-based polyethylene glycol monomethyl ether to 150mL of N,N-dimethylformamide, heat to 40℃, stir and react for 18h, distill under reduced pressure, add saturated sodium carbonate aqueous solution, stir and let stand to separate the layers, separate and remove the aqueous phase, and dry the oil phase to obtain a water-based substrate wetting agent based on polyether modified siloxane.

[0028] Comparative Example 1 used commercially available polyether-modified silicone oil (model Shandong Dayi Chemical DY-ET333) as a wetting agent.

[0029] Comparative Example 2 (1) Add 10g of wetting agent precursor (prepared in Example 1) and 1.5g of amino-terminated polyethylene glycol monomethyl ether (model Shanghai Pengsheng Biotechnology MPEG1000-NH2) to 120mL of N,N-dimethylformamide, heat to 70℃, stir and react for 12h, distill under reduced pressure, add saturated sodium carbonate aqueous solution, stir and let stand to separate the layers, separate and remove the aqueous phase, and dry the oil phase to obtain an aqueous substrate wetting agent based on polyether modified siloxane.

[0030] Add the wetting agent to deionized water, stir and disperse to prepare an aqueous solution with a concentration of 5-12 g / L, and measure the surface tension using a surface tension meter at a test temperature of 25℃.

[0031] Table 1 Surface Tension Test

[0032] After testing, the wetting agents of Examples 1-3 showed lower surface tension and better amphiphilicity. This is mainly because, compared to traditional polyether-modified silicone oils, which are limited by the low silicon hydrogen content of the raw material hydrogen-containing silicone oil, resulting in fewer grafted polyether molecular chains (prepared by hydrosilylation reaction of hydrogen-containing silicone oil and allyl polyether), thus affecting amphiphilicity and surface activity and not conducive to reducing surface tension, the polysiloxane side chains of the wetting agents of Examples 1-3 contain more hydrophilic polyether molecular chains and imino groups, which is beneficial to improving the hydrophilicity of the wetting agent and giving it higher amphiphilicity, thereby effectively reducing surface tension and improving wetting effect.

[0033] 55g of water-soluble acrylic resin (model Jintuan 5207), 8g of amino resin (model Cytec 325), 8g of water, 10mL of ethanol, 13mL of ethylene glycol butyl ether, 1mL of dipropylene glycol butyl ether, 0.2g of leveling agent Jintuan 387, 1g of silicone defoamer Jintuan 3300W, 24g of red pigment paste, and 1g of wetting agent (prepared from the respective examples and comparative examples) were stirred and dispersed to prepare an acrylic resin coating.

[0034] 55g of water-soluble acrylic resin (model Jintuan 5207), 8g of amino resin (model Cytec 325), 8g of water, 10mL of ethanol, 13mL of ethylene glycol butyl ether, 1mL of dipropylene glycol butyl ether, 0.2g of leveling agent Jintuan 387, 1g of silicone defoamer Jintuan 3300W, and 24g of red pigment paste were stirred and dispersed to prepare a blank control of acrylic resin coating.

[0035] The viscosity of the red paint was tested using a rotational viscometer at 30 rpm.

[0036] Table 2 Viscosity Test of Acrylic Resin Coatings

[0037] 72g of waterborne polyurethane emulsion (model Sansheng Chemical PU3721), 0.2g of leveling agent Jintuan 387, 1g of silicone defoamer Jintuan 3300W, 26g of red pigment paste, and 1g of wetting agent (prepared from each example and comparative example, respectively) were stirred and dispersed to prepare a polyurethane coating.

[0038] 72g of waterborne polyurethane emulsion (model Sansheng Chemical PU3721), 0.2g of leveling agent Jintuan 387, 1g of silicone defoamer Jintuan 3300W, and 26g of red pigment were stirred and dispersed to prepare a blank control of polyurethane coating.

[0039] The viscosity of the polyurethane coating was tested using a rotational viscometer at 30 rpm.

[0040] Table 3 Viscosity test of polyurethane coatings

[0041] After testing, it was found that when the wetting agents of Examples 1-3 were added to acrylic resin and polyurethane resin, the resulting coatings had lower viscosity. This was mainly because the wetting and dispersing agents contained a large number of ester groups and amide bonds. The ester groups had excellent compatibility with acrylic resin, and the amide bonds could form hydrogen bonds with the urethane groups of polyurethane resin, resulting in better compatibility and dispersibility between the wetting agent and acrylic resin and polyurethane resin, and better wetting and dispersing performance and viscosity reduction performance.

[0042] The acrylic resin coating was applied to the surface of the substrate and baked at 80°C for 2 hours. The state of the surface coating film was then observed. Figure 1 The results showed that the acrylic resin coating blank control caused pinholes due to the addition of excessive silicone defoamer, while the coating film with added wetting agent (prepared in Example 1) not only effectively avoided pinholes, but also significantly reduced the surface tension as seen on the board surface, with the coating film penetrating the blank formulation by nearly 0.5 cm. Figure 2 The paint film with added wetting agent exhibits excellent leveling properties, high gloss, and no pinholes on the entire board surface, indicating that the wetting agent has excellent leveling properties and excellent stability.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane, characterized in that, The preparation method includes: (1) Add diaminopropyl polysiloxane and triethylamine to N,N-dimethylformamide, add fumarate chloride dropwise in an ice-water bath, stir and react, distill under reduced pressure and add the product to water, stir and let stand to separate the layers, separate and remove the aqueous phase, dry the oil phase to obtain the wetting agent precursor. (2) Add wetting agent precursor and alanine-based polyethylene glycol monomethyl ether to N,N-dimethylformamide, stir and react, distill under reduced pressure, add saturated sodium carbonate aqueous solution, stir and let stand to separate the layers, separate and remove the aqueous phase, and dry the oil phase to obtain a water-based substrate wetting agent based on polyether modified siloxane.

2. The method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane according to claim 1, characterized in that, The ratio of diaminopropyl polysiloxane, triethylamine, and fumarate in (1) is 100g:(7.6-8.2)g:(10-13)g.

3. The method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane according to claim 1, characterized in that, The reaction temperature in (1) is 20-40℃ and the reaction time is 9-15h.

4. The method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane according to claim 1, characterized in that, The reaction temperature in (2) is 40-70℃ and the reaction time is 12-18h.

5. The method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane according to claim 1, characterized in that, The ratio of the wetting agent precursor and alanine-based polyethylene glycol monomethyl ether in (2) is 100g:(15-40)g.

6. The method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane according to claim 1, characterized in that, The preparation method of the alanine-based polyethylene glycol monomethyl ether includes: adding polyethylene glycol monomethyl ether, β-alanine, and p-toluenesulfonic acid to toluene, stirring and reacting, distilling under reduced pressure, extracting, distilling the organic phase under reduced pressure, and drying to obtain alanine-based polyethylene glycol monomethyl ether.

7. The method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane according to claim 6, characterized in that, The mass ratio of polyethylene glycol monomethyl ether, β-alanine, and p-toluenesulfonic acid is 100g:(7.8-8.6):(0.8-1).

8. The method for preparing an aqueous substrate wetting agent based on polyether-modified siloxane according to claim 6, characterized in that, In the preparation method of the alanine-based polyethylene glycol monomethyl ether, the reaction temperature is 100-115℃ and the reaction time is 6-9h.

9. An aqueous substrate wetting agent based on polyether-modified siloxane obtained by the preparation method according to any one of claims 1-8.

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