Composite water-based latex with flame-retardant effect, and preparation method and application thereof

Abstract

The application discloses a kind of composite water-based latex with flame-retardant effect and its preparation method and application, the composition of the composite water-based latex includes phosphate-modified silica sol, methyl methacrylate phosphate, anionic emulsifier, non-ionic emulsifier, water-soluble initiator, concentrated ammonia and water;Preparation method is with methyl methacrylate phosphate as pH regulator, modified silica sol is prepared by sol-gel method, then it is incorporated into acrylate monomer mixture, under the action of emulsifier and water-soluble initiator, the composite water-based latex uniformly dispersed in water phase;After composite water-based latex is cured into coating, due to the obvious synergistic flame-retardant effect of silicon and phosphorus elements in the system, the thermal stability of coating is significantly improved, and can be applied to flame-retardant coating field.

Description

Technical Field

[0001] This invention relates to a composite water-based latex, particularly a composite water-based latex with flame-retardant properties, and also to the preparation method and application of the aforementioned composite water-based latex. Background Technology

[0002] Since the beginning of the 21st century, people's living standards have improved significantly, leading to a surge in the use of flammable decorative materials such as wood, fiber, plastic, and rubber in our living environments, resulting in frequent fires. Coatings, a type of polymer material, are films formed through a curing process that provide decoration and protection to the substrate, playing a vital role in our lives. Fire-retardant coatings, as a fire prevention method, are defined as special coatings applied to the surface of combustible substrates to reduce surface combustion characteristics, delay the spread of fire, or applied to building components to improve the fire resistance limit of the structure, thereby buying time for rescue operations.

[0003] Waterborne acrylic latexes possess excellent gloss and color retention, good film-forming properties, good weather resistance, low price, and simple synthesis process, thus enjoying widespread use in the coatings industry. However, traditional acrylic latex films have a serious drawback: flammability, posing a safety hazard to people's lives. Currently, most fire-retardant coatings are prepared by adding flame retardants as fillers to the coating system; however, flame retardants used as fillers have poor compatibility with resins and are prone to forming clusters in the coating, thus seriously affecting various properties of the coating, such as dispersibility, stability, and corrosion resistance. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a composite water-based latex with strong stability, uniform dispersion, and flame retardant properties, and also to provide a method for preparing and applying the above-mentioned composite water-based latex.

[0005] Technical solution: The present invention provides a flame-retardant composite water-based latex, comprising the following components by weight percentage:

[0006]

[0007] The phosphate-modified silica sol comprises the following components by weight percentage:

[0008]

[0009]

[0010] The acrylate monomer mixture comprises the following components by weight percentage:

[0011]

[0012] The anionic emulsifier is potassium monododecyl phosphate; the nonionic emulsifier is C16-18 alcohol polyoxyethylene ether phosphate or isomeric tridecyl alcohol polyoxyethylene ether phosphate; and the water-soluble initiator is potassium persulfate or ammonium persulfate.

[0013] The method for preparing the phosphate-modified silica sol includes the following steps:

[0014] (1) Dissolve tetraethyl orthosilicate and γ-methacryloyloxypropyltrimethoxysilane in anhydrous ethanol and stir at 500-800 rpm for 1-5 minutes until they are evenly mixed.

[0015] (2) Add phosphate methacrylate to the system, mix well, and then heat the system to 50-70°C;

[0016] (3) The stirring speed is controlled at 500-800 rpm and the reaction temperature is controlled at 50-70℃. Deionized water is gradually added to the system, and the addition time is controlled at 0.5-3 hours. Then the reaction is continued at 50-70℃ for 3-6 hours to obtain phosphate ester modified silica sol.

[0017] The method for preparing the above-mentioned flame-retardant composite water-based latex includes the following steps:

[0018] (1) A portion of anionic emulsifier, nonionic emulsifier, and water-soluble initiator are added to water to form a mixed solution. Then, a mixture of acrylate monomers and methacrylate phosphate double bonds are added and dispersed at high speed to obtain a pre-emulsion.

[0019] (2) Pour the remaining anionic emulsifier, nonionic emulsifier, and water-soluble initiator into water and mix them evenly. Then add a portion of the pre-emulsion obtained in step (1) to obtain the base reaction mixture. Heat and stir the reaction mixture and add the remaining pre-emulsion.

[0020] (3) Add phosphate-modified silica sol, keep warm, cool, and then add concentrated ammonia water under stirring to make the pH of the system 9-10, thus obtaining a composite water-based latex with flame retardant properties.

[0021] In steps (1) and (2), the ratio of anionic emulsifier to nonionic emulsifier is 20-35:65-80, the ratio of water-soluble initiator to water is 20-40:60-80, and the ratio of water is 55-64:36-45, wherein the water is preferably deionized water.

[0022] In step (2), the amount of the pre-emulsion added in step (1) is 4 to 6 wt% of the total amount obtained in step (1).

[0023] In step (2), the heating and stirring reaction specifically involves heating to 80-82°C, stirring at a speed of 200-800 rpm for 0.1-1 hours, heating to 82-85°C, and gradually adding the remaining pre-emulsion over a time of 5-8 hours.

[0024] The reaction conditions for step (3) are as follows: phosphate ester modified silica sol is added at 85-88℃ and a rotation speed of 500-1000 rpm, and the temperature is maintained for 1-5 hours.

[0025] This invention also discloses the application of the above-mentioned flame-retardant composite water-based latex in the field of flame-retardant coatings.

[0026] The flame-retardant coating is a composite water-based latex fire-retardant coating, the components of which include a composite water-based latex with flame-retardant properties, a water-based dispersant, a water-based defoamer, a water-based leveling agent, a water-based wetting agent, antimony trioxide, chlorinated paraffin, aluminum hydroxide, bentonite, titanium dioxide, distilled water, and alcohol ester twelve.

[0027] Invention Principle: This invention provides a flame-retardant composite water-based latex that utilizes chemical bonds to effectively combine modified silica sol and acrylic latex, thereby achieving uniform dispersion of the two phases and improving the dispersibility of the composite water-based latex. Simultaneously, the effective combination of organosilicon sol and phosphate ester in the system enhances the flame retardancy of the coating. Furthermore, the abundant phosphate ions in the system can form chelates with metal ions, and their addition has a good effect on inhibiting metal corrosion.

[0028] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) The composite water-based latex has good dispersibility and strong stability, and at the same time has the effects of flame retardancy and metal corrosion prevention. The flame retardancy time of the cured coating is up to 20 minutes; (2) The above-mentioned composite water-based latex reaction preparation process is simple, does not require anhydrous and oxygen-free operation, and does not require high-pressure reactor operation, which is conducive to industrial production; (3) When applied to the field of flame retardant coating, composite water-based latex fireproof coating can be prepared, and its fire resistance limit is further improved to 3 hours. It has a very strong flame retardant effect, and other properties of the coating, such as corrosion resistance, are also significantly improved. Attached Figure Description

[0029] Figure 1 The image shows the cross-sectional morphology of the composite waterborne latex curing coating obtained in Example 1. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the embodiments. The test materials used in the embodiments can all be purchased through conventional means.

[0031] Example 1

[0032] A flame-retardant composite water-based latex comprises the following components:

[0033]

[0034]

[0035] The phosphate-modified silica sol includes the following components:

[0036]

[0037] The preparation method is as follows: (1) Tetraethyl orthosilicate and γ-methacryloyloxypropyltrimethoxysilane are mixed and dissolved in anhydrous ethanol, and stirred at 500 rpm for 5 minutes until they are evenly mixed.

[0038] (2) Add phosphate methacrylate to the system, mix well, and then heat the system to 50°C.

[0039] (3) The stirring speed is controlled at 500 rpm and the reaction temperature is controlled at 50℃. Deionized water is gradually added to the system, and the addition time is controlled at 3 hours. Then the reaction is continued at 50℃ for 6 hours to obtain the designed phosphate ester modified silica sol.

[0040] The acrylate monomer mixture consists of methyl methacrylate, styrene, butyl acrylate, and isooctyl acrylate.

[0041]

[0042] The method for preparing the above-mentioned flame-retardant composite water-based latex includes the following steps:

[0043] (1) Weigh out 20 wt% of potassium monododecyl phosphate, 35 wt% of C16-18 alcohol polyoxyethylene ether phosphate, and 20 wt% of potassium persulfate, and pour them into a deionized aqueous phase system. The amount of deionized water used here is 64 wt% of the total amount. Then add the acrylate monomer mixture and methacrylate phosphate to the system and disperse at high speed at 1500 rpm for 5 minutes to obtain a preemulsion.

[0044] (2) The remaining potassium monododecyl phosphate, C16-18 alcohol polyoxyethylene ether phosphate, and potassium persulfate were poured into the remaining deionized water and mixed evenly. Then, 4 wt% of the pre-emulsion obtained in step (1) was added to obtain the base reaction mixture. The system was heated to 80°C and stirred at 200 rpm for 1 hour. Then, the temperature was raised to 82°C, and the remaining pre-emulsion was gradually added dropwise over a period of 8 hours.

[0045] (3) At 86℃ and 800 rpm, phosphate-modified silica sol was added, the system was kept warm for 3 hours, and after cooling, concentrated ammonia was added under stirring to make the pH of the system 9-10, thus obtaining a composite water-based latex with flame retardant properties.

[0046] Example 2

[0047] A flame-retardant composite water-based latex comprises the following components:

[0048]

[0049] The phosphate-modified silica sol includes the following components:

[0050]

[0051] The preparation method is as follows: (1) Tetraethyl orthosilicate and γ-methacryloyloxypropyltrimethoxysilane are mixed and dissolved in anhydrous ethanol, and stirred at 600 rpm for 4 minutes until they are evenly mixed.

[0052] (2) Add phosphate methacrylate to the system, mix well, and then heat the system to 55°C.

[0053] (3) The stirring speed was controlled at 600 rpm and the reaction temperature was controlled at 55℃. Deionized water was gradually added to the system over a period of 2.5 hours. The reaction was then maintained at 55℃ for 5 hours to obtain the designed phosphate-modified silica sol.

[0054] The acrylate monomer mixture is composed of methyl methacrylate, styrene, butyl acrylate, and isooctyl acrylate.

[0055]

[0056] The method for preparing the above-mentioned flame-retardant composite water-based latex includes the following steps:

[0057] (1) Weigh 28 wt% of potassium monododecyl phosphate, 32 wt% of isotridecyl alcohol polyoxyethylene ether phosphate, and 25 wt% of ammonium persulfate, and pour them into a deionized aqueous phase system. The amount of deionized water used here is 60 wt% of the total amount. Then add the acrylate monomer mixture and methacrylate phosphate to the system and disperse at high speed at 1600 rpm for 4 minutes to obtain a preemulsion.

[0058] (2) After mixing the remaining potassium monododecyl phosphate, isotridecyl alcohol polyoxyethylene ether phosphate, and ammonium persulfate into the remaining deionized water, add 4.5wt% of the pre-emulsion obtained in step (1) to obtain the base reaction material. The system is heated to 80.5℃ and stirred at 400 rpm for 0.8 hours. Then, the temperature is raised to 84℃ and the remaining pre-emulsion is added dropwise over a period of 7 hours.

[0059] (3) At 85℃ and 1000 rpm, phosphate-modified silica sol was added, the system was kept warm for 5 hours, and after cooling, concentrated ammonia was added under stirring to make the pH of the system 9-10, thus obtaining a composite water-based latex with flame retardant properties.

[0060] Example 3

[0061] A flame-retardant composite water-based latex comprises the following components:

[0062]

[0063] The phosphate-modified silica sol includes the following components:

[0064]

[0065] The preparation method is as follows: (1) Tetraethyl orthosilicate and γ-methacryloyloxypropyltrimethoxysilane are mixed and dissolved in anhydrous ethanol, and stirred at 700 rpm for 3 minutes until they are evenly mixed.

[0066] (2) Add phosphate methacrylate to the system, mix well, and then heat the system to 65°C.

[0067] (3) The stirring speed is controlled at 700 rpm and the reaction temperature is controlled at 65℃. Deionized water is gradually added to the system, and the addition time is controlled at 1 hour. Then the reaction is continued at 65℃ for 4 hours to obtain the designed phosphate ester modified silica sol.

[0068] The acrylate monomer mixture is composed of methyl methacrylate, styrene, butyl acrylate, and isooctyl acrylate.

[0069]

[0070] The method for preparing the above-mentioned flame-retardant composite water-based latex includes the following steps:

[0071] (1) Weigh out 30 wt% of potassium monododecyl phosphate, 25 wt% of C16-18 alcohol polyoxyethylene ether phosphate, and 35 wt% of ammonium persulfate, and pour them into the deionized aqueous phase system. The amount of deionized water used here is 58 wt% of the total amount. Then add the acrylate monomer mixture and methacrylate phosphate to the system and disperse at high speed at 1800 rpm for 3 minutes to obtain the preemulsion.

[0072] (2) Pour the remaining potassium monododecyl phosphate, C16-18 alcohol polyoxyethylene ether phosphate, and ammonium persulfate into the remaining deionized water and mix them evenly. Then add 5.5wt% of the pre-emulsion obtained in step (1) to obtain the base reaction material. Heat the system to 81.5℃ and stir the reaction at 600 rpm for 0.6 hours. Then heat the system to 83℃ and gradually add the remaining pre-emulsion. The addition time is controlled within 6 hours.

[0073] (3) At 87℃ and 600 rpm, phosphate-modified silica sol was added, the system was kept at the temperature for 2 hours, and then cooled to obtain a composite water-based latex with flame retardant properties.

[0074] Example 4

[0075] A flame-retardant composite water-based latex comprises the following components:

[0076]

[0077] The phosphate-modified silica sol includes the following components:

[0078]

[0079] The preparation method is as follows: (1) Tetraethyl orthosilicate and γ-methacryloyloxypropyltrimethoxysilane are mixed and dissolved in anhydrous ethanol, and stirred at 800 rpm for 1 minute to mix evenly.

[0080] (2) Add phosphate methacrylate to the system, mix well, and then heat the system to 70°C.

[0081] (3) The stirring speed is controlled at 800 rpm and the reaction temperature is controlled at 70℃. Deionized water is gradually added to the system, and the addition time is controlled at 0.5 hours. Then the reaction is continued at 70℃ for 3 hours to obtain the designed phosphate ester modified silica sol.

[0082] The acrylate monomer mixture is composed of methyl methacrylate, styrene, butyl acrylate, and isooctyl acrylate.

[0083]

[0084] The method for preparing the above-mentioned flame-retardant composite water-based latex includes the following steps:

[0085] (1) Weigh out 35 wt% of potassium monododecyl phosphate, 20 wt% of C16-18 alcohol polyoxyethylene ether phosphate, and 40 wt% of potassium persulfate, and pour them into a deionized aqueous phase system. The amount of deionized water used here is 64 wt% of the total amount. Then add the acrylate monomer mixture and methacrylate phosphate to the system and disperse at high speed at 2000 rpm for 1 minute to obtain a preemulsion.

[0086] (2) Pour the remaining potassium monododecyl phosphate, C16-18 alcohol polyoxyethylene ether phosphate, and potassium persulfate into the remaining deionized water and mix them evenly. Then add 6 wt% of the pre-emulsion obtained in step (1) to obtain the base reaction material. Heat the system to 82°C and stir the reaction at 800 rpm for 1 hour. Then heat the system to 82°C and gradually add the remaining pre-emulsion dropwise over a period of 8 hours.

[0087] (3) At 88℃ and 500 rpm, phosphate-modified silica sol was added, the system was kept warm for 1 hour, and after cooling, concentrated ammonia was added under stirring to make the pH of the system 9-10, thus obtaining a composite water-based latex with flame retardant properties.

[0088] The composite water-based latex prepared in Example 1 was coated and cured. The coating was observed by scanning electron microscopy. The cross-sectional morphology of the cured coating is as follows: Figure 1 As shown, the phosphate-modified silica sol is spherically and uniformly dispersed in the coating polymer, effectively playing a role in flame retardancy and corrosion prevention.

[0089] Flame retardant performance tests were conducted on the composite water-based latex of the present invention:

[0090] The composite water-based latexes prepared in Examples 1-4 were coated and cured, and the flame retardant time of the cured coating was measured. The results are shown in Table 1.

[0091] Table 1. Flame retardant time of the cured coating of the composite waterborne latex prepared in the examples

[0092]

[0093]

[0094] As can be seen from Table 1, the cured coating film exhibits excellent flame retardant properties. Among them, the cured coating film of Example 3 has the highest flame retardant time of 20 minutes, indicating that the flame retardant time of the coating is positively proportional to the content of phosphate-modified silica sol in the system.

[0095] Based on the composite water-based latex prepared according to this invention, its application in fire-retardant coatings was verified:

[0096] The epoxy phosphate-doped acrylate composite waterborne latex obtained in Example 1 was used to prepare a waterborne acrylic anti-corrosion and fireproof coating according to Table 2.

[0097] Table 2. Fire-retardant coatings prepared based on the composite water-based latex of the present invention

[0098] raw materials w / ％ Composite water-based latex 35 Aqueous dispersants 0.4 Water-based defoamer 0.2 Water-based leveling agent 0.2 Water-based wetting agents 0.2 Antimony trioxide 2 Chlorinated paraffin 2.5 Aluminum hydroxide 3 Bentonite 0.5 Titanium dioxide 10 distilled water 42 Alcohol ester dodecyl 4

[0099] The prepared anti-corrosion and fireproof coating based on the composite water-based latex of Example 1 was applied to the surface of a metal substrate by brushing, spraying, or rolling. After being left for 7 days, its various properties were tested, and the experimental results are shown in Table 3.

[0100] Table 3. Performance of the anti-corrosion and fire-retardant coating based on the composite waterborne latex of Example 1

[0101]

[0102]

[0103] As shown in Table 3, the flame-retardant composite water-based latex of the present invention, when applied to composite water-based latex fireproof coatings, exhibits significant improvements in various properties, especially in fire resistance, with a fire resistance limit of up to 3 hours, demonstrating a strong flame-retardant effect.

Claims

1. A composite water-based latex with flame-retardant properties, characterized in that, The composite water-based latex comprises the following components by weight percentage: 10-20 wt% phosphate-modified silica sol; 35-50 wt% acrylate monomer mixture; Phosphate methacrylate 0.1–2 wt%; Anionic emulsifier 1-5 wt%; Nonionic emulsifier 1-5 wt%; Water-soluble initiator 0.1–0.5 wt%; Concentrated ammonia solution 0.5–1 wt%; Water 35-50 wt%; The phosphate-modified silica sol comprises the following components by weight percentage: Tetraethyl orthosilicate 35–45 wt%; γ-Methacryloxypropyltrimethoxysilane 1–5 wt%; Anhydrous ethanol 38–50 wt%; Phosphate methacrylate 1-5 wt%; Water 1-10 wt%; The acrylate monomer mixture comprises the following components by weight percentage: 20-60 wt% methyl methacrylate; 5-50 wt% styrene Butyl acrylate 5-25 wt%; 10-15 wt% isooctyl acrylate; The anionic emulsifier is potassium monododecyl phosphate; the nonionic emulsifier is C16-18 alcohol polyoxyethylene ether phosphate or isomeric tridecyl alcohol polyoxyethylene ether phosphate.

2. The composite water-based latex according to claim 1, characterized in that, The water-soluble initiator is potassium persulfate or ammonium persulfate.

3. A method for preparing the flame-retardant composite water-based latex according to claim 1, characterized in that, Includes the following steps: (1) A portion of anionic emulsifier, nonionic emulsifier, and water-soluble initiator are added to water to form a mixed solution, and then a mixture of acrylate monomers and methacrylate phosphate double bonds are added and dispersed at high speed to obtain a pre-emulsion; (2) After mixing the remaining anionic emulsifier, nonionic emulsifier, and water-soluble initiator in water, add a portion of the pre-emulsion obtained in step (1) to obtain the base reaction mixture; heat and stir the reaction and add the remaining pre-emulsion dropwise. (3) Add phosphate-modified silica sol, keep warm, cool, and then add concentrated ammonia water under stirring to make the pH value of the system 9-10, so as to obtain a composite water-based latex with flame retardant properties.

4. The method for preparing the composite water-based latex according to claim 3, characterized in that, In steps (1) and (2), the ratio of anionic emulsifier to nonionic emulsifier is 20-35:65-80, the ratio of water-soluble initiator to water is 20-40:60-80, and the ratio of water is 55-64:36-45.

5. The method for preparing the composite water-based latex according to claim 3, characterized in that, In step (2), the amount of the pre-emulsion added in step (1) is 4 to 6 wt% of the total amount obtained in step (1).

6. The method for preparing the composite water-based latex according to claim 3, characterized in that, In step (2), the heating and stirring reaction specifically involves heating to 80-82°C, stirring at a speed of 200-800 rpm for 0.1-1 hours, heating to 82-85°C, and gradually adding the remaining pre-emulsion over a time of 5-8 hours.

7. The method for preparing the composite water-based latex according to claim 3, characterized in that, The reaction conditions for step (3) are as follows: phosphate ester modified silica sol is added at 85-88℃ and a rotation speed of 500-1000 rpm, and the temperature is maintained for 1-5 hours.

8. The application of the composite water-based latex with flame-retardant properties as described in claim 1 in the field of flame-retardant coatings.

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