Process for preparing a waterborne multicolor coating continuous phase emulsion

Abstract

The application discloses a preparation process of a water-based multicolor coating continuous phase emulsion, which changes the adding mode of an initiator, adds the initiator into a reaction kettle at one time before polymerization, shortens the reaction time, guarantees polymerization activity, and greatly reduces the use amount of the initiator; meanwhile, part of the emulsion obtained through the first stage polymerization is transferred into a post-treatment kettle in advance, pre-emulsion II is added for the second stage polymerization, and finally, the obtained emulsion is mixed in the post-treatment kettle, so that the negative influence caused by excessive dispersion of high-Tg polymers on the surface of latex particles is reduced, the water whitening resistance and the protective colloid stability of the emulsion are improved under the condition of maintaining the freeze-thaw stability.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation process, in particular to a preparation process of a water-based multi-color coating continuous phase emulsion. BACKGROUND

[0002] Multi-color paint is a new type of environmentally friendly building coating prepared by innovative colloid technology, which can not only make the coating present the patterns and colors of high-grade decorative materials such as natural granite and wallpaper, and obtain humanized and personalized patterns, but also provide different size and color patterns according to the different shapes of new and old buildings and the needs of customers, so as to achieve the unity of decorative effect and functionality.

[0003] Multi-color paint is divided into continuous phase emulsion and dispersed phase emulsion, wherein the continuous phase emulsion provides stability for multi-color paint, and the dispersed phase emulsion is selected according to different plate effects, and the two are used together. However, the continuous phase emulsion of multi-color paint on the market generally has the defects of poor water white resistance and poor protective glue stability, which limits its application. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a preparation process of a water-based multi-color coating continuous phase emulsion. The present inventor found that the main factors affecting the water white resistance and protective glue stability of the continuous phase emulsion are as follows: first, the initiator generally has a short half-life, and in order to ensure the polymerization activity, a continuous dropwise addition of initiator is generally used to initiate the reaction during the polymerization process, but the present inventor accidentally found that this method will add a significant excess of initiator relative to the polymerized monomers, and the initiator is hydrophilic, which can easily lead to poor emulsion water white resistance and poor protective glue stability when the amount of addition is large. Second, in order to ensure the freeze-thaw stability of the paint film, the traditional continuous phase emulsion generally adopts a preparation process of wrapping low-Tg polymers with high-Tg polymers, so that the outer periphery of the latex particle contains more polymers formed by hard monomers, but the outer layer of hard monomers generally has strong hydrophilicity, which can also damage the emulsion water white resistance and protective glue stability of the emulsion.

[0005] Based on the above technical problems, the present application aims to provide a solution by changing the addition method of the initiator, adding it to the reaction kettle at one time before the polymerization reaction, and shortening the reaction time to ensure the polymerization activity, thereby greatly reducing the amount of initiator; second, part of the emulsion obtained by the first stage polymerization reaction is transferred to the post-treatment kettle in advance, and pre-emulsion II is added for the second stage polymerization, and the obtained emulsion is finally mixed in the post-treatment kettle, which can reduce the negative effects caused by excessive high-Tg polymers dispersed on the surface of the latex particle, and improve the emulsion water white resistance and protective glue stability while maintaining the freeze-thaw stability.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A preparation process of an aqueous multicolor coating continuous phase emulsion, comprising the following steps:

[0008] 1) Preparation of pre-emulsion I, pre-emulsion II

[0009] Mixing raw material components containing hard monomers, soft monomers and functional monomers with emulsifiers and water to form pre-emulsion I;

[0010] Mixing raw material components containing hard monomers and functional monomers with emulsifiers and water to form pre-emulsion II;

[0011] 2) Bottoming of the reaction kettle

[0012] Adding water and emulsifiers as a bottoming liquid into the reaction kettle, and heating to 80-90℃;

[0013] 3) First stage polymerization

[0014] Adding all initiators into the reaction kettle at once, uniformly dispersing, then adding pre-emulsion I dropwise for first stage polymerization reaction, controlling the dropwise addition amount of pre-emulsion I to be 40-85%, preferably 50-70% of the total mass within 30-60 min, and starting to transfer the polymerization emulsion to the post-treatment kettle; at the same time, continuing to add the remaining pre-emulsion I dropwise into the reaction kettle, and completing the dropwise addition within 10-40 min, controlling the flow rate of the polymerization emulsion transferred to the post-treatment kettle to be the same as the flow rate of the remaining pre-emulsion I added dropwise into the reaction kettle; after the dropwise addition is completed, maintaining the temperature for 5-20 min;

[0015] 4) Second stage polymerization

[0016] Continuing to add pre-emulsion II dropwise into the reaction kettle, and completing the dropwise addition within 20-40 min, then maintaining the temperature for 0.5-1 h, and then transferring all the polymerization emulsion to the post-treatment kettle;

[0017] 5) Post-treatment

[0018] After the polymerization emulsion in the post-treatment kettle is cooled to 65-75℃, the oxidizing agent and reducing agent solutions are added dropwise synchronously; after the dropwise addition is completed, the temperature is cooled to 40-50℃, the neutralizing agent is added for neutralization, then the defoaming agent and preservative are added, and the filtrate is discharged to obtain the aqueous multicolor coating continuous phase emulsion.

[0019] In a preferred embodiment of the present application, the pre-emulsion I contains the following mass fractions of each component:

[0020]

[0021] Preferably, the pre-emulsion II contains the following mass fractions of each component:

[0022]

[0023] In a preferred embodiment of the present application, the hard monomer is one or both of styrene and methyl methacrylate;

[0024] Preferably, the soft monomer is one or more of isooctyl acrylate, butyl acrylate, and ethyl acrylate;

[0025] Preferably, the functional monomer is one or more of acrylic acid, methacrylic acid, and vinyltrimethoxysilane.

[0026] In a preferred embodiment of the present application, the emulsifier is one or more of sodium trideceth sulfate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium p-styrenesulfonate, and ammonium allyloxy polyethyleneglycol sulfate.

[0027] Preferably, the initiator is one or both of ammonium persulfate and sodium persulfate.

[0028] Preferably, the oxidizing agent is one or more of tert-butyl hydroperoxide, ammonium persulfate, and sodium persulfate; and the reducing agent is one or more of sodium bisulfite, ascorbic acid, and sodium metabisulfite.

[0029] In a preferred embodiment of the present application, the amount of emulsifier used as the primer in step 2) is 1-3 parts by mass, preferably 1-2 parts by mass, and the amount of water used is 300-500 parts by mass, preferably 320-440 parts by mass.

[0030] In a preferred embodiment of the present application, in step 3), the initiator is added in an amount of 0.2-0.6% of the total mass of the hard monomer, the soft monomer, and the functional monomer.

[0031] In a preferred embodiment of the present application, in step 5), the oxidizing agent is added in an amount of 0.2-1 parts by mass, and the reducing agent is added in an amount of 0.1-1 parts by mass.

[0032] Preferably, the neutralizing agent is added in an amount such that the pH of the emulsion after neutralization is 7.5-8.5.

[0033] Preferably, the antifoaming agent is added in an amount of 0.2-0.6 parts by mass.

[0034] Preferably, the preservative is added in an amount of 1-3 parts by mass.

[0035] Preferably, the neutralizing agent is an ammonia water and / or NaOH solution; the antifoaming agent is Tego-825 and / or Tego-1488 from Evonik; and the preservative is an isothiazolinone MIT preservative.

[0036] In a preferred embodiment of the present application, in step 5), the dropping time of the oxidizing agent and the reducing agent solution is 30-60 min.

[0037] In a preferred embodiment of the present application, an external circulation heat exchange system is arranged outside the reactor to keep the temperature in the reactor constant.

[0038] The present application can prepare a continuous phase emulsion of multi-color paint with excellent water white resistance and protective colloid stability by adjusting the polymerization process and the amount of raw materials. DETAILED DESCRIPTION

[0039] The present application will be further described below by specific examples, which are only used to illustrate the present application and do not limit the scope of the present application.

[0040] In the following examples and comparative examples of the present application, the raw materials are obtained from commercial channels unless otherwise specified.

[0041] The test methods mainly involved in the detailed description of the present application are as follows:

[0042] Particle size: Malvern ZS90 particle size instrument is used, polystyrene latex model is adopted, water is used as the dispersion medium, and general purpose analysis method is used for determination.

[0043] Solid content: about 1.0 g of emulsion is weighed and placed in a 5 cm diameter aluminum foil, spread evenly, and then placed in a 150 degree oven for 20 min to determine the dry weight, and the solid content is calculated.

[0044] Protective colloid stability: 7% protective colloid GTS solution is mixed with the continuous phase emulsion at a ratio of 1:1, and the viscosity change is tested after standing at room temperature (23℃) for 7 days; when the viscosity increase change is <10%, it is recorded as A level, when the viscosity increase change is between 10-50%, it is recorded as B level, and when the viscosity increase change is >50%, it is recorded as C level.

[0045] Emulsion water white resistance: the continuous phase paint is coated on a PVC plate, and after curing at room temperature (23℃) for 1 day, half of the PVC plate is soaked in water for 4 days, and the color difference value ΔE of the soaked area and the unsoaked area is tested using a color difference meter.

[0046] Multi-color water white resistance and water white recovery: the prepared multi-color paint is dried at 25℃ for 7 days, soaked in water for 4 days, and after recovery for 1 day, the surface whitening is compared with the standard sample, and the whitening is scored according to the whitening, with a full score of 5 points, and the lower the score, the whiter the paint film.

[0047] Freeze-thaw stability: 50 g of the emulsion was frozen at -5°C for 18 h, and then placed at room temperature for 6 h. The above cycle was repeated for three times. The emulsion was rated as A if no change was observed, B if slight agglomeration was observed, and C if coagulation was observed.

[0048] [Example 1] Preparation of the continuous phase emulsion 1-1 for multi-color paint

[0049] Pre-emulsion I was prepared by mixing 158 g of deionized water, 2.2 g of sodium dodecyl sulfate, 116 g of butyl acrylate, 3.6 g of methacrylic acid, and 219.4 g of methyl methacrylate in a pre-emulsification kettle 1 and stirring thoroughly;

[0050] Pre-emulsion II was prepared by mixing 30 g of deionized water, 0.6 g of sodium dodecyl sulfate, 4.1 g of styrene, 1.8 g of acrylic acid, and 46.7 g of methyl methacrylate in a pre-emulsification kettle 2 and stirring thoroughly;

[0051] 1.1 g of sodium persulfate was weighed and dissolved in 8 g of deionized water to prepare an initiator solution;

[0052] 350 g of deionized water was added to a reaction kettle, which was heated to 85°C, and 1.8 g of sodium dodecyl sulfate was added. The prepared initiator solution was added to the reaction kettle, and pre-emulsion I was added dropwise after being dispersed for 3 min, with the reaction temperature being controlled at 85°C. When the amount of pre-emulsion I added dropwise accounted for 56% of the total mass of pre-emulsion I, the reaction kettle was connected to a post-treatment kettle, and the dropping speed was controlled to be consistent with the transfer speed. Pre-emulsion II was continuously added dropwise for 30 min, and then the emulsion was kept at 85°C for 30 min. The emulsion in the reaction kettle was transferred to the post-treatment kettle, and the mixture was stirred uniformly. Then the temperature of the mixture in the post-treatment kettle was lowered to 70°C, 8.6 g of t-butyl hydroperoxide solution (7% by mass) and 8.6 g of erythorbic acid solution (7% by mass) were added dropwise, and the dropping time was 40 min. When the temperature was lowered to below 50°C, 2.7 g of ammonia water was added for neutralization, and then 0.4 g of defoamer Tego-1488 and 2.1 g of preservative Kordek MLX were added, to obtain the continuous phase emulsion 1-1 for multi-color paint.

[0053] [Example 2] Preparation of the continuous phase emulsion 1-2 for multi-color paint

[0054] Pre-emulsion I was prepared by mixing 180 g of deionized water, 4.0 g of sodium dodecyl sulfate, 200 g of isooctyl acrylate, 7 g of acrylic acid, 100 g of methyl methacrylate, and 35.8 g of styrene in a pre-emulsification kettle 1 and stirring thoroughly;

[0055] Pre-emulsion II preparation: 25 g deionized water, 0.9 g tridecyl alcohol polyoxyethylene ether sodium sulfate, 8 g styrene, 1.5 g acrylic acid, 1.2 g vinyl trimethoxysilane, 42.8 g methyl methacrylate were prepared in pre-emulsion kettle 2 and stirred thoroughly;

[0056] 0.8 g ammonium persulfate was weighed and dissolved in 8 g deionized water to prepare an initiator solution;

[0057] Into the reaction kettle, 340 g deionized water was added and heated to 85 °C, and 2.0 g sodium dodecyl sulfate was added. The prepared initiator solution was added to the reaction kettle, and after dispersion for 3 min, pre-emulsion I was added dropwise, and the reaction temperature was controlled at 85 °C. When the amount of pre-emulsion I added dropwise accounted for 67% of the total mass of pre-emulsion I, the material was transferred from the reaction kettle to the post-treatment kettle, and the dropping speed was controlled to be consistent with the transfer speed. The dropping was continued for 25 min to complete the dropping of pre-emulsion I, and the temperature was kept for 10 min. Pre-emulsion II was continuously added dropwise into the reaction kettle for 20 min, and then the temperature was kept for 30 min. The emulsion in the reaction kettle was transferred to the post-treatment kettle, and mixed uniformly. Then the temperature of the material in the post-treatment kettle was lowered to 75 °C, 8.6 g of tert-butyl hydroperoxide solution (mass concentration 7%) and 8.6 g of isoascorbic acid solution (mass concentration 7%) were added dropwise, and the dropping time was 40 min. The temperature was lowered to below 50 °C, 2.7 g of ammonia water was added for neutralization, and then 0.4 g of defoamer Tego-825 and 2.1 g of preservative Kordek MLX were added to obtain the continuous phase emulsion 1-2 of the multi-color coating.

[0058]

Example 3

[0059] Pre-emulsion I preparation: 100 g deionized water, 1.8 g allyloxy polyoxyethylene ether ammonium sulfate salt, 164.4 g isooctyl acrylate, 12 g acrylic acid, 165.4 g methyl methacrylate were prepared in pre-emulsion kettle 1 and stirred thoroughly;

[0060] Pre-emulsion II preparation: 10 g deionized water, 0.07 g sodium dodecyl sulfate, 4 g acrylic acid, 50.8 g methyl methacrylate were prepared in pre-emulsion kettle 2 and stirred thoroughly;

[0061] 1.8 g ammonium persulfate was weighed and dissolved in 8 g deionized water to prepare an initiator solution;

[0062] Into a reaction kettle, 435 g of deionized water was added and heated to 85°C, and 1.6 g of sodium dodecyl sulfate was added. The prepared initiator solution was added into the reaction kettle, and after dispersion for 3 min, the pre-emulsion I was added dropwise, and the reaction temperature was controlled at 85°C. When the amount of pre-emulsion I added dropwise reached 75% of the total amount of pre-emulsion I, the material was transferred from the reaction kettle to the post-treatment kettle, and the dropping speed was controlled to be consistent with the transfer speed. The dropping was continued for 20 min to complete the dropping of pre-emulsion I, and the temperature was kept for 10 min. The pre-emulsion II was continuously added dropwise into the reaction kettle, and the dropping was continued for 20 min, and then the temperature was kept for 30 min. The emulsion in the reaction kettle was transferred to the post-treatment kettle, and mixed uniformly. Then the material in the post-treatment kettle was cooled to 65°C, and 8.6 g of t-butyl hydroperoxide solution (mass concentration 7%) and 8.6 g of sodium pyrosulfite (mass concentration 7%) were added dropwise, and the dropping time was 40 min. When the temperature was cooled to below 50°C, 2.7 g of ammonia water was added for neutralization, and then 0.4 g of defoaming agent Tego-825 and 2.1 g of preservative Kordek MLX were added, to obtain the continuous phase emulsion 1-3 of multi-color paint.

[0063] Preparation of continuous phase emulsion 1-4 of multi-color paint

[0064] Preparation of pre-emulsion I: 153.5 g of deionized water, 2.2 g of sodium dodecyl sulfate, 156.4 g of isooctyl acrylate, 7 g of acrylic acid, and 179.4 g of methyl methacrylate were prepared in a pre-emulsification kettle 1 and stirred thoroughly;

[0065] Preparation of pre-emulsion II: 21.1 g of deionized water, 0.2 g of sodium dodecyl sulfate, 1.3 g of acrylic acid, and 51.8 g of methyl methacrylate were prepared in a pre-emulsification kettle 2 and stirred thoroughly;

[0066] 1.1 g of ammonium persulfate was weighed and dissolved in 8 g of deionized water to prepare an initiator solution;

[0067] Into a reaction kettle, 372 g of deionized water was added and heated to 85°C, and 1.6 g of sodium dodecyl sulfate was added. The prepared initiator solution was added into the reaction kettle, and after dispersion for 3 min, the pre-emulsion I was added dropwise, and the reaction temperature was controlled at 85°C. When the pre-emulsion I was added dropwise to 71% of the total mass, the material was transferred from the reaction kettle to the post-treatment kettle, and the dropwise addition speed was controlled to be consistent with the transfer speed. The dropwise addition of the pre-emulsion I was continued for 20 min, and the temperature was kept for 10 min. The pre-emulsion II was continuously added dropwise into the reaction kettle, and the total dropwise addition time was 20 min, followed by keeping the temperature for 30 min. The emulsion in the reaction kettle was transferred to the post-treatment kettle, and mixed uniformly. Then the material in the post-treatment kettle was cooled to 75°C, and 8.6 g of t-butyl hydroperoxide solution (mass concentration 7%) and 8.6 g of erythorbic acid solution (mass concentration 7%) were added dropwise, and the dropwise addition time was 40 min. When the temperature was cooled to below 50°C, 2.7 g of ammonia water was added for neutralization, and then 0.4 g of defoaming agent Tego-825 and 2.1 g of preservative Kordek MLX were added, to obtain the continuous phase emulsion 1-4 of the multi-color paint.

[0068] Preparation of the continuous phase emulsion 1-5 of the multi-color paint

[0069] Preparation of the pre-emulsion I: 158 g of deionized water, 2.0 g of sodium dodecyl sulfate, 1.5 g of sodium p-styrenesulfonate, 78.2 g of isooctyl acrylate, 78.2 g of butyl acrylate, 7 g of acrylic acid, and 140.2 g of methyl methacrylate were prepared in the pre-emulsification kettle 1 and stirred thoroughly;

[0070] Preparation of the pre-emulsion II: 42 g of deionized water, 0.8 g of sodium dodecyl sulfate, 1.5 g of acrylic acid, and 90.8 g of methyl methacrylate were prepared in the pre-emulsification kettle 2 and stirred thoroughly;

[0071] 2.2 g of ammonium persulfate was weighed and dissolved in 8 g of deionized water to prepare an initiator solution;

[0072] Into a reactor, 400 g of deionized water was added and heated to 85°C, and 1.1 g of sodium dodecyl sulfate was added. The prepared initiator solution was added into the reactor, and after dispersion for 3 min, the pre-emulsion I was added dropwise, and the reaction temperature was controlled at 85°C. When the amount of pre-emulsion I added dropwise reached 67% of the total amount of pre-emulsion I, the material was transferred from the reactor to the post-treatment reactor, and the dropping speed was controlled to be consistent with the transferring speed. The dropping of pre-emulsion I was continued for 15 min, and the temperature was kept for 15 min. The pre-emulsion II was continuously added dropwise into the reactor, and the dropping was continued for 20 min, and then the temperature was kept for 30 min. The emulsion in the reactor was transferred to the post-treatment reactor, and mixed uniformly. Then the temperature of the material in the post-treatment reactor was lowered to 75°C, and 8.6 g of t-butyl hydroperoxide solution (7% by mass) and 8.6 g of erythorbic acid solution (7% by mass) were added dropwise, and the dropping time was 40 min. When the temperature was lowered to below 50°C, 2.7 g of ammonia water was added for neutralization, and then 0.4 g of defoaming agent Tego-825 and 2.1 g of preservative Kordek MLX were added, to obtain the continuous phase emulsion 1-5 of multi-color paint.

[0073]

Comparative Example 1

[0074] The continuous phase emulsion was prepared according to the same method as in Example 4, except that the emulsion was not transferred from the reactor to the post-treatment reactor during the polymerization process, and the emulsion in the reactor was transferred to the post-treatment reactor only once after the completion of the dropping of pre-emulsion I and emulsion II and the completion of the polymerization reaction, and then the post-treatment was performed.

[0075]

Comparative Example 2

[0076] First, the pre-emulsion I and the emulsion II were prepared according to the same method as in Example 4; then 0.8 g of ammonium persulfate was weighed and dissolved in 8 g of deionized water to prepare a first initiator solution; 0.8 g of ammonium persulfate was weighed and dissolved in 30 g of deionized water to prepare a second initiator solution;

[0077] Into a reaction kettle, 370.8 g of deionized water was added and heated to 85°C, and 1.6 g of sodium dodecyl sulfate was added. The first initiator solution was added to the reaction kettle, and after 3 minutes of dispersion, the pre-emulsion I and the second initiator solution were added dropwise simultaneously, and the reaction temperature was controlled at 85°C. When 71% of the pre-emulsion I was added dropwise, the reaction kettle was transferred to a post-treatment kettle, and the dropwise addition was continued for 20 minutes to complete the dropwise addition of the pre-emulsion I, and the temperature was maintained for 10 minutes. The pre-emulsion II and the remaining second initiator solution were continuously added dropwise to the reaction kettle, and the total dropwise addition time was 20 minutes, followed by 30 minutes of temperature maintenance. The emulsion in the reaction kettle was transferred to the post-treatment kettle, and the mixture was uniformly mixed. Then the material in the post-treatment kettle was cooled to 75°C, and 8.6 g of t-butyl hydroperoxide solution (7% by mass) and 8.6 g of erythorbic acid solution (7% by mass) were added dropwise, with a dropwise addition time of 40 minutes. When the temperature was lowered to below 50°C, 2.7 g of ammonia water was added for neutralization, and then 0.4 g of antifoaming agent Tego-825 and 2.1 g of preservative Kordek MLX were added, to obtain the continuous phase emulsion 2-2 of the multi-color paint.

[0078]

Comparative Example 3

[0079] First, the pre-emulsion I and the emulsion II were prepared according to the same method as in Example 4; then 0.8 g of ammonium persulfate was weighed and dissolved in 8 g of deionized water to prepare the first initiator solution; 0.8 g of ammonium persulfate was weighed and dissolved in 30 g of deionized water to prepare the second initiator solution;

[0080] Into a reaction kettle, 370.8 g of deionized water was added and heated to 85°C, and 1.6 g of sodium dodecyl sulfate was added. The first initiator solution was added to the reaction kettle, and after 3 minutes of dispersion, the pre-emulsion I and the second initiator solution were added dropwise simultaneously, and the reaction temperature was controlled at 85°C. When 71% of the pre-emulsion I was added dropwise, the reaction kettle was transferred to a post-treatment kettle, and the dropwise addition was continued for 20 minutes to complete the dropwise addition of the pre-emulsion I, and the temperature was maintained for 10 minutes. The pre-emulsion II and the remaining second initiator solution were continuously added dropwise to the reaction kettle, and the total dropwise addition time was 20 minutes, followed by 30 minutes of temperature maintenance. The emulsion in the reaction kettle was transferred to the post-treatment kettle, and the mixture was uniformly mixed. Then the material in the post-treatment kettle was cooled to 75°C, and 8.6 g of t-butyl hydroperoxide solution (7% by mass) and 8.6 g of erythorbic acid solution (7% by mass) were added dropwise, with a dropwise addition time of 40 minutes. When the temperature was lowered to below 50°C, 2.7 g of ammonia water was added for neutralization, and then 0.4 g of antifoaming agent Tego-825 and 2.1 g of preservative Kordek MLX were added, to obtain the continuous phase emulsion 2-2 of the multi-color paint.

[0081] The continuous phase emulsion prepared in each example and comparative example was respectively subjected to particle size, solid content and protective colloid stability test, then the continuous phase paint was prepared according to the formula in Table 1, and water white resistance and freeze-thaw stability test was carried out, and the test results are shown in Table 2.

[0082] Table 1, continuous phase paint preparation formula

[0083] Material Type Material Name Mass / g Supplier Deionized Water Deionized Water 73 In-house PG Anti-freeze 5 Dow Chemical NXZ Defoamer 1 Nopco AMP-95 Neutralizer 0.5 Dow LX150 Biocide 1 DuPont DF-19 Mold Inhibitor 1 Sumitomo Texanol Coalescent 15 Eastman A401 Thickener 3.3 Wanhua Continuous Phase Emulsion Emulsion 250 Patent Preparation

[0084] Table 2, performance test results

[0085]

[0086]

[0087] As can be seen from Table 2, the continuous phase emulsion prepared in the present example has excellent emulsion water white resistance and multi-color water white resistance, and the water white recovery is also good, and has excellent stability with protective colloid compared with the comparative example.

[0088] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the method of the present application, a number of improvements and supplements can also be made, which should be considered as the protection scope of the present application.

Claims

1. A preparation process for a continuous phase emulsion of water-based multicolor coatings, characterized in that, Includes the following steps: 1) Prepare pre-emulsion I and pre-emulsion II The raw material components, including hard monomers, soft monomers, and functional monomers, are mixed with emulsifiers and water to form pre-emulsion I; The raw material components, including hard monomers and functional monomers, are mixed with emulsifiers and water to form pre-emulsion II; 2) Bottom preparation of the reactor Add water and emulsifier as a base solution to the reactor and heat to 80-90℃; 3) First-stage aggregation Add all the initiator to the reactor at once, disperse it evenly, and then add preemulsion I dropwise to initiate the first stage of polymerization. Control the amount of preemulsion I added to reach 40-85% of its total mass within 30-60 minutes, and begin transferring the polymer emulsion to the post-processing reactor. Simultaneously, continue adding the remaining preemulsion I dropwise to the reactor, completing the addition within 10-40 minutes. Control the flow rate of the polymer emulsion transferred to the post-processing reactor to be the same as the flow rate of the remaining preemulsion I added to the reactor. After the addition is complete, maintain the temperature for 5-20 minutes. 4) Second-stage aggregation Continue to add pre-emulsion II dropwise to the reactor, and add it completely within 20-40 minutes. Then keep it warm for 0.5-1 hour, and transfer all the polymer emulsion to the post-processing reactor. 5) Post-processing After cooling the polymer emulsion in the post-treatment vessel to 65-75℃, oxidant and reducing agent solutions are added dropwise simultaneously. After the addition is completed, the temperature is lowered to 40-50℃, a neutralizing agent is added for neutralization, and then an antifoaming agent and preservative are added. The mixture is then filtered and discharged to obtain the continuous phase emulsion of the water-based multicolor coating.

2. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 1, characterized in that, In step 3), the amount of pre-emulsion I added is controlled to reach 50-70% of its total mass within 30-60 minutes, and the polymer emulsion is transferred to the post-processing tank.

3. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 1, characterized in that, The preemulsion I comprises the following components in parts by weight:

4. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 3, characterized in that, The preemulsion I comprises the following components in parts by weight:

5. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 3, characterized in that, The preemulsion II comprises the following components in parts by weight:

6. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 5, characterized in that, The preemulsion II comprises the following components in parts by weight:

7. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 1, characterized in that, The hard monomer is one or both of styrene and methyl methacrylate.

8. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 7, characterized in that, The soft monomer is one or more of isooctyl acrylate, butyl acrylate, and ethyl acrylate.

9. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 7, characterized in that, The functional monomer is one or more of acrylic acid, methacrylic acid, and vinyltrimethoxysilane.

10. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to any one of claims 1-9, characterized in that, The emulsifier is one or more of the following: sodium tridecyl alcohol polyoxyethylene ether sulfate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium p-styrene sulfonate, and allyloxy polyoxyethylene ether ammonium sulfate.

11. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 10, characterized in that, The initiator is one or both of ammonium persulfate and sodium persulfate.

12. The preparation process of the waterborne multicolor coating continuous phase emulsion according to claim 10, characterized in that, The oxidizing agent is one or more of tert-butyl hydroperoxide, ammonium persulfate, and sodium persulfate; the reducing agent is one or more of sodium bisulfite, ascorbic acid, and sodium metabisulfite.

13. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to any one of claims 1-9, characterized in that, In step 2), the amount of emulsifier used as the base coat is 1-3 parts by weight, and the amount of water is 300-500 parts by weight.

14. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 13, characterized in that, In step 2), the amount of emulsifier used as the base coat is 1-2 parts by weight, and the amount of water is 320-440 parts by weight.

15. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 13, characterized in that, In step 3), the amount of initiator added is 0.2-0.6% of the total mass of hard monomers, soft monomers and functional monomers.

16. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 15, characterized in that, In step 5), the amount of oxidant added is 0.2-1 parts by mass, and the amount of reducing agent added is 0.1-1 parts by mass.

17. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 16, characterized in that, The amount of neutralizing agent added is such that the pH of the neutralized emulsion is 7.5-8.

5.

18. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 16, characterized in that, The amount of defoamer added is 0.2-0.6 parts by weight.

19. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 16, characterized in that, The amount of the preservative added is 1-3 parts by weight.

20. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to claim 16, characterized in that, The neutralizing agent is ammonia and / or NaOH solution; the defoamer is Evonik Degussa Tego-825 and / or Tego-1488; and the preservative is an isothiazolinone MIT preservative.

21. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to any one of claims 1-9, characterized in that, In step 5), the oxidant and reducing agent solutions are added dropwise over a period of 30-60 minutes.

22. The preparation process of the continuous phase emulsion of waterborne multicolor coating according to any one of claims 1-9, characterized in that, The reactor is equipped with an external circulation heat exchange system to maintain a constant temperature inside the reactor.

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