Acrylic emulsion as well as application and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and particularly discloses an acrylic emulsion as well as application and a preparation method thereof. The acrylic emulsion comprises the following raw materials by mass: 6-8% of a nonionic macromolecular polymer; 0.5 to 0.8 percent of methacrylic acid; 8-12% of styrene; 2 to 14% of 2-ethylhexyl acrylate; 8.6 to 15.3 percent of methyl methacrylate; 4.2 to 4.6 percent of hydroxyethyl methylacrylate; 0.15%-0.17% of ammonia water; 0.1 to 0.2 percent of adipic acid dihydrazide; 0.4 to 0.65 percent of a water-soluble initiator; and the balance of deionized water. The non-ionic macromolecular high polymer is a cross-linkable non-ionic macromolecular high polymer or a copolymerizable non-ionic macromolecular high polymer. The acrylic emulsion can be used for single-component water-based paint or double-component water-based paint, and has the advantages of high water resistance, high weather resistance and the like.

Description

Technical Field

[0001] The present application relates to the technical field of water-based coatings, and more specifically, to an acrylic emulsion, an application thereof, and a preparation method thereof. Background Art

[0002] Acrylic emulsion is a material that can be used as a film-forming substance for single-component or two-component coatings. Acrylic emulsion is usually obtained by emulsion polymerization with the addition of an emulsifier.

[0003] Usually, small molecule emulsifiers are used in the synthesis of acrylic emulsions. The acrylic emulsions prepared with small molecule emulsifiers usually have excellent appearance transparency. However, due to the small molecular weight of the emulsifier, it is highly hydrophilic and easily floats on the surface after film formation. Therefore, the water resistance and aging resistance of the paint film prepared with the acrylic emulsion formed by the small molecule emulsifier are not ideal.

[0004] In order to solve the above problems, most of them are solved by using reactive emulsifiers or macromolecular emulsifiers. Reactive emulsifiers are made by grafting small molecule emulsifiers onto the main chain through double bond free radicals, so that after the small molecule emulsifier forms a film, the phenomenon of small molecule emulsifiers migrating to the surface is reduced, thereby improving the water resistance and chemical resistance of the paint film; macromolecular emulsifiers are usually called soap-free emulsion polymerization, which synthesizes small molecule emulsifiers into emulsifiers with larger molecular weight to improve the performance of the entire paint film. However, the use of reactive emulsifiers still needs to be combined with small molecule emulsifiers, otherwise the synthetic emulsion has poor stability and appearance; and although the molecular weight of macromolecular emulsifiers is increased, it does not significantly improve the overall water resistance of the paint film.

[0005] Therefore, there is an urgent need for an acrylic emulsion to improve the shortcomings of the paint film formed by the acrylic emulsion in terms of mechanical physical properties and weather resistance. Summary of the invention

[0006] In order to improve the mechanical and physical properties and weather resistance of acrylic emulsion, the present application provides an acrylic emulsion and a preparation method thereof, which adopts the following technical scheme:

[0007] In a first aspect, the present application provides an acrylic emulsion comprising the following raw materials in percentage by weight:

[0008] Non-ionic macromolecular polymer 6-8%;

[0009] Methacrylic acid 0.5-0.8%;

[0010] Styrene 8-12%;

[0011] Isooctyl acrylate 12-14%;

[0012] Methyl methacrylate 8.6-15.3%;

[0013] Hydroxyethyl methacrylate 4.2-4.6%;

[0014] Ammonia 0.15-0.17%;

[0015] Adipic acid dihydrazide 0.1-0.2%;

[0016] Water-soluble initiator 0.4-0.65%;

[0017] Deionized water balance;

[0018] The nonionic macromolecular polymer is a cross-linkable nonionic macromolecular polymer or a copolymerizable nonionic macromolecular polymer.

[0019] By adopting the above technical scheme, preferably adding a non-ionic macromolecular polymer to the acrylic emulsion, it is possible to effectively avoid the phenomenon that the small molecule emulsifier has a small molecular weight, strong hydrophilicity, and is easy to float on the surface after film formation, resulting in poor water resistance and aging resistance of the paint film formed by the acrylic emulsion, thereby effectively improving the water resistance and aging resistance of the paint film formed by the acrylic emulsion.

[0020] Optionally, the nonionic macromolecular polymer includes the following raw materials:

[0021] Hydrogenated bisphenol A epoxy resin 9.73-10.78%;

[0022] Vinyl comonomer 5-8%;

[0023] Polyethylene glycol 64.77-71.82%;

[0024] Acrylamide compounds 3-5%;

[0025] Polyetheramine 8-10%;

[0026] Boron trifluoride derivative 0.2-0.3%;

[0027] Terminator 1-2%;

[0028] Inhibitor 0.2%;

[0029] The vinyl comonomer contains an epoxy group;

[0030] The acrylamide compound includes methacrylamide or hydroxymethyl acrylamide.

[0031] By adopting the above technical scheme, the introduction of acrylamide compounds, on the one hand, the double bonds of acrylamide can undergo a ring-opening reaction with the epoxy groups in the hydrogenated bisphenol A epoxy resin to achieve free polymerization in the polymer, and the double bonds react with the epoxy groups to generate a three-dimensional network structure with a larger and denser molecular weight, so as to improve the chemical resistance of the polymer; on the other hand, the introduction of amide groups in the polymer can make the polymer self-crosslink with adipic acid dihydrazide in the acrylic emulsion at room temperature, thereby increasing the degree of crosslinking in the acrylic emulsion and further improving the water resistance of the polymer and the entire paint film.

[0032] The introduction of polyetheramine into the polymer provides the polymer with redundant ether bonds, which are stable nonionic hydrophilic groups, thereby further improving the emulsification and stability of the overall macromolecular polymer.

[0033] It is preferred to add hydrogenated bisphenol A epoxy resin to the polymer. Compared with ordinary epoxy, hydrogenated bisphenol A epoxy resin is not easy to yellow at high temperature and has better weather resistance. Therefore, the selection of hydrogenated bisphenol A epoxy resin can effectively improve the weather resistance of the polymer, and the impact on the weather resistance of the entire system is relatively low.

[0034] Optionally, the epoxide equivalent of the hydrogenated bisphenol A epoxy resin is 450-500 g / mol.

[0035] By adopting the above technical scheme, it is preferred to use 500g / mol equivalent of hydrogenated bisphenol A epoxy resin. This equivalent of epoxy resin is more universal, easy to purchase and has a low cost. In addition, the viscosity of the epoxy resin at this equivalent is easier to control in the later chain extension and is not easy to gel.

[0036] Optionally, the vinyl comonomer includes one or both of glycidyl acrylate and epoxy methacrylate monomers.

[0037] By adopting the above technical scheme, a vinyl comonomer containing an epoxy group is preferably used. On the one hand, the vinyl comonomer containing an epoxy group has relatively good compatibility with hydrogenated bisphenol A epoxy, and can be used as a diluent in the polymer to reduce the overall viscosity of the polymer, and the epoxy group can also react with polyetheramine, which is beneficial to the polymer reaction in the polymer; on the other hand, a double bond structure is introduced into the polymer. When preparing the acrylic emulsion in the later stage, the double bond structure can undergo a copolymerization grafting reaction with other reactants in the acrylic acid, which is beneficial to the formation of more cross-linked structures in the acrylic emulsion, thereby improving the overall stability and weather resistance of the acrylic emulsion.

[0038] Optionally, the polyethylene glycol is selected from any one or more of polyethylene glycol 2000, polyethylene glycol 4000 or polyethylene glycol 6000.

[0039] By adopting the above technical scheme, preferably polyethylene glycol 2000, polyethylene glycol 4000 or polyethylene glycol 6000 is added to the polymer. Polyethylene glycol 2000, polyethylene glycol 4000 or polyethylene glycol 6000 is relatively easy to purchase, and the polyethylene glycol with the above molecular weight can synthesize a polymer with suitable viscosity and hydrophilicity. In addition, the polyethylene glycol with the above molecular weight has strong controllability and operability in the entire process of polymer polymerization.

[0040] Optionally, the boron trifluoride derivative is selected from any one or more of boron trifluoride ethyl ether, boron trifluoride ethylamine and boron trifluoride benzylamine.

[0041] By adopting the above technical scheme, the boron trifluoride derivative has the advantages of strong selectivity and high catalytic activity in the reaction between epoxy groups and hydroxyl groups, so the polymer can obtain excellent stability and emulsification effect.

[0042] Optionally, the terminator is any compound containing a hydroxyl group, and the inhibitor is any compound that can inhibit free radical polymerization.

[0043] Optionally, the terminator is preferably an alcohol or alcohol ether compound, and further preferably one or a combination of deionized water, propylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol butyl ether; the inhibitor is preferably a quinone compound, and further preferably one or a combination of methylhydroquinone, benzoquinone, and p-benzoquinone.

[0044] By adopting the above technical solution, the terminator can deactivate the boron trifluoride derivative, thereby terminating the reaction between the epoxy group and the hydroxyl group. Since the reaction between the epoxy group and the hydroxyl group is an endless reaction, the terminator must be added to deactivate the catalyst to stop the reaction. The inhibitor can prevent the epoxy vinyl monomer from self-polymerizing, thereby reducing the possibility of affecting the subsequent acrylic emulsion polymerization reaction due to the epoxy vinyl monomer self-polymerization.

[0045] Optionally, the preparation of the non-ionic macromolecular polymer is as follows: 20% by mass of hydrogenated bisphenol A resin is placed in a container, a vinyl comonomer is added, the temperature is increased, a polyether amine is added, and the reaction is carried out at a constant temperature to obtain a reaction liquid; the remaining 80% by mass of hydrogenated bisphenol A resin, polyethylene glycol, acrylamide compound and inhibitor are added to the reaction liquid, the temperature is increased, vacuum dehydration is performed, a boron trifluoride derivative is added, the reaction is carried out at a constant temperature, a terminator is added, the temperature is reduced, and the material is discharged to obtain a non-ionic macromolecular polymer.

[0046] In a second aspect, the present application provides an application of an acrylic emulsion, using the following technical solution:

[0047] An application of an acrylic emulsion, wherein the acrylic emulsion is applied to a single-component water-based paint or a two-component water-based paint.

[0048] In a third aspect, the present application provides a method for preparing an acrylic emulsion, using the following technical solution:

[0049] A method for preparing an acrylic emulsion comprises the following steps:

[0050] S1, mixing non-ionic macromolecular polymer, 1% of the total mass of initiator and water, heating to 80-85° C. to obtain a mixed solution;

[0051] S2, mixing the remaining initiator with the acrylic acid monomer to obtain a mixture;

[0052] S3, add the mixture to the mixed solution dropwise, complete the addition within 6-8 hours, react at a constant temperature, cool to 40-60°C, add ammonia water and adipic acid dihydrazide, mix, cool, filter, and discharge.

[0053] In summary, this application has the following beneficial effects:

[0054] 1. The acrylic emulsion in this application does not contain any external emulsifier, but the paint film formed by the acrylic emulsion still has good water resistance and weather resistance.

[0055] 2. The acrylic emulsion in this application has a better emulsification effect and has the advantage of strong pigment wetting and dispersibility.

[0056] 3. The acrylic emulsion in this application has strong thermodynamic and kinetic stability.

[0057] 4. The acrylic emulsion in this application does not require the introduction of emulsifiers, has high decorative properties, excellent mechanical properties, and great market potential.

[0058] 5. The acrylic emulsion in this application has relatively low cost, simple preparation process, easy control and high economic value. DETAILED DESCRIPTION

[0059] The present application is further described in detail below with reference to the embodiments.

[0060] Preparation example of nonionic macromolecular polymer

[0061] Preparation Example 1

[0062] Take 1.65g of hydrogenated bisphenol A and put it into a four-necked flask, then add 6g of epoxy-containing vinyl comonomer, and heat to 80°C; after the temperature rises, add 1.62g of polyetheramine, keep the temperature constant for 3h, and set aside; add 6.6g of hydrogenated bisphenol A epoxy, 10g of polyethylene glycol, 1.5g of acrylamide compounds and inhibitors to the above reaction products; while heating, vacuum dehydration is carried out to 130°C, and the temperature is kept constant until no water is extracted; after the above conditions are constant, add 0.004g of catalyst boron trifluoride derivatives, and keep the temperature constant for 6h; after the insulation reaction is completed, add 2g of terminator, cool down, and discharge to obtain a non-ionic macromolecular polymer.

[0063] Among them, the terminator is preferably an alcohol or alcohol ether compound, and further preferably one or a combination of deionized water, propylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol butyl ether; the inhibitor is preferably a quinone compound, and further preferably one or a combination of methylhydroquinone, benzoquinone, and p-benzoquinone.

[0064] Specifically, in this preparation example, the terminator is preferably propylene glycol methyl ether, and the inhibitor is preferably benzoquinone.

[0065] Example

[0066] Examples 1-3

[0067] In a first aspect, the present application provides an acrylic emulsion comprising a nonionic macromolecular polymer, methacrylic acid, styrene, isooctyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, aqueous ammonia, adipic acid dihydrazide, a water-soluble initiator and deionized water. The specific mass is shown in Table 1 below.

[0068] The nonionic macromolecular polymer is a cross-linkable nonionic macromolecular polymer or a copolymerizable nonionic macromolecular polymer. Specifically, the nonionic macromolecular polymer is the nonionic macromolecular polymer prepared in Preparation Example 1.

[0069] The water-soluble initiator is selected from ammonium persulfate, sodium persulfate and potassium persulfate, as shown in Table 1 below.

[0070] In a second aspect, the present application provides an application of an acrylic emulsion, which is applied to a single-component water-based paint or a two-component water-based paint.

[0071] In a third aspect, the present application provides a method for preparing an acrylic emulsion, comprising the following steps:

[0072] S1, mixing non-ionic macromolecular polymer, 1% of the total mass of initiator and water, heating to 80-85° C. to obtain a mixed solution;

[0073] S2, mixing the remaining initiator with the acrylic acid monomer to obtain a mixture;

[0074] S3, add the mixture to the mixed solution dropwise, complete the addition within 6-8 hours, react at a constant temperature, cool to 40-60°C, add ammonia water and adipic acid dihydrazide, mix, cool, filter, and discharge.

[0075] Comparative Example 1

[0076] The difference from Example 2 is:

[0077] In a first aspect, the present application provides an acrylic emulsion comprising 5 g of a nonionic macromolecular polymer, 0.45 g of methacrylic acid, 7 g of styrene, 11 g of isooctyl acrylate, 8 g of methyl methacrylate, 4 g of hydroxyethyl methacrylate, 0.05 g of aqueous ammonia, 0.14 g of adipic acid dihydrazide, 0.3 g of a water-soluble initiator and the remainder of deionized water, as shown in Table 1 below.

[0078] The nonionic macromolecular polymer is the nonionic macromolecular polymer prepared in Preparation Example 1.

[0079] The water-soluble initiator is selected from ammonium persulfate.

[0080] Comparative Example 2

[0081] The difference from Example 2 is:

[0082] In a first aspect, the present application provides an acrylic emulsion comprising 12 g of a nonionic macromolecular polymer, 1 g of methacrylic acid, 15 g of styrene, 16 g of isooctyl acrylate, 20 g of methyl methacrylate, 6 g of hydroxyethyl methacrylate, 0.3 g of aqueous ammonia, 0.2 g of adipic acid dihydrazide, 0.8 g of a water-soluble initiator and the remainder of deionized water, as shown in Table 1 below.

[0083] The nonionic macromolecular polymer is the nonionic macromolecular polymer prepared in Preparation Example 1.

[0084] The water-soluble initiator is selected from ammonium persulfate.

[0085] Table 1

[0086] Component / (g) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Macromolecular polymer 6 7 8 5 12 Methacrylic acid 0.5 0.7 0.8 0.45 1 Styrene 8 10 12 7 15 2-Ethylhexyl acrylate 12 13 14 11 16 Methyl Methacrylate 10 13 15 8 20 Hydroxyethyl Methacrylate 4.3 4.5 4.6 4 6 Adipic acid dihydrazide 0.1 0.15 0.2 0.05 0.3 ammonia 0.15 0.16 0.17 0.14 0.2 Ammonium Persulfate 0.4 / / 0.3 / Sodium Persulfate / 0.55 / / / Potassium Persulfate / / 0.6 / 0.8 Deionized water (total 100) margin margin margin margin margin

[0087] Comparative Example 1

[0088] The difference from Example 3 is that:

[0089] In a first aspect, the present application provides an acrylic emulsion comprising 8 g of sodium dodecyl sulfate, 0.8 g of methacrylic acid, 12 g of styrene, 14 g of isooctyl acrylate, 15 g of methyl methacrylate, 4.6 g of hydroxyethyl methacrylate, 0.17 g of aqueous ammonia, 0.2 g of adipic acid dihydrazide, 0.6 g of a water-soluble initiator and the remainder of deionized water, as shown in Table 2 below.

[0090] The water-soluble initiator is selected from potassium persulfate.

[0091] Comparative Example 2

[0092] The difference from Example 3 is that:

[0093] In the first aspect, the present application provides an acrylic emulsion, including 8g SR10 Adec, 0.8g methacrylic acid, 12g styrene, 14g isooctyl acrylate, 15g methyl methacrylate, 4.6g hydroxyethyl methacrylate, 0.17g ammonia water, 0.2g adipic acid dihydrazide, 0.6g water-soluble initiator and the balance deionized water, as shown in Table 2 below.

[0094] The water-soluble initiator is selected from potassium persulfate.

[0095] Comparative Example 3

[0096] The difference from Example 3 is that:

[0097] In a first aspect, the present application provides an acrylic emulsion, comprising 8 g Cops 1 Solvay, 0.8 g methacrylic acid, 12 g styrene, 14 g isooctyl acrylate, 15 g methyl methacrylate, 4.6 g hydroxyethyl methacrylate, 0.17 g ammonia water, 0.2 g adipic acid dihydrazide, 0.6 g water-soluble initiator and the balance deionized water, as shown in Table 2 below.

[0098] The water-soluble initiator is selected from potassium persulfate.

[0099] Table 2

[0100]

[0101]

[0102] Table 3 Performance test

[0103] Example Emulsion state Solid content (%) Stability (50℃ / 14d) Slagging rate (%) Example 1 Transparent 40.20 pass 0.2 Example 2 Transparent 40.11 pass 0.25 Example 3 Transparent 40.32 pass 0.3 Comparative Example 1 milky 40.05 Failed 0.6 Comparative Example 2 Transparent 38.22 pass 1.5

[0104] Table 4 Performance test

[0105]

[0106] Combining the performance test comparison in Table 3-4, we can find that:

[0107] 1. By comparing Examples 1-3 and Comparative Examples 1-2, it can be seen that the acrylic emulsion can be successfully prepared by the method of the technical solution of the present application, and the acrylic emulsion prepared in Example 3 has better performance. The reason why the thermal storage of Comparative Example 1 failed is that the amount of macromolecular polymer added is too small, resulting in the inability to wrap the entire system, resulting in poor stability of the acrylic emulsion. The solid content of the acrylic emulsion in Comparative Example 2 is low and the slagging rate is also high, because the amount of macromolecular polymer added is too large, resulting in the entire system being too hydrophilic, resulting in a large slagging rate of the acrylic emulsion.

[0108] 2. By comparing Example 3 with Comparative Examples 1-3, it can be learned that: Comparative Examples 1-3 all use mainstream emulsifiers, while the acrylic emulsion prepared in the present application has a great advantage in alcohol wiping and water resistance, and this type of emulsion can effectively solve the problems of chemical resistance and water resistance, and will not affect the overall storage stability of the resin, and the market application prospect is very broad.

[0109] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. An acrylic emulsion, characterized in that: The following raw materials are included in mass percentage: Non-ionic macromolecular polymer 6-8%; Methacrylic acid 0.5-0.8%; Styrene 8-12%; Isooctyl acrylate 12-14%; Methyl methacrylate 8.6-15.3%; Hydroxyethyl methacrylate 4.2-4.6%; Ammonia 0.15-0.17%; Adipic acid dihydrazide 0.1-0.2%; Water-soluble initiator 0.4-0.65%; Deionized water balance; The nonionic macromolecular polymer is a cross-linkable nonionic macromolecular polymer or a copolymerizable nonionic macromolecular polymer.

2. An acrylic emulsion according to claim 1, characterized in that: The nonionic macromolecular polymer comprises the following raw materials: Hydrogenated bisphenol A epoxy resin 9.73-10.78%; Vinyl comonomer 5-8%; Polyethylene glycol 64.77-71.82%; Acrylamide compounds 3-5%; Polyetheramine 8-10%; Boron trifluoride derivative 0.2-0.3%; Terminator 1-2%; Inhibitor 0.2%; The vinyl comonomer contains an epoxy group; The acrylamide compound includes methacrylamide or hydroxymethyl acrylamide.

3. An acrylic emulsion according to claim 2, characterized in that: The epoxy equivalent of the hydrogenated bisphenol A epoxy resin is 450-500 g / mol.

4. An acrylic emulsion according to claim 2, characterized in that: The vinyl comonomer includes one or both of glycidyl (meth)acrylate and epoxy (meth)acrylate monomer.

5. An acrylic emulsion according to claim 2, characterized in that: The polyethylene glycol is selected from any one or more of polyethylene glycol 2000, polyethylene glycol 4000 or polyethylene glycol 6000.

6. An acrylic emulsion according to claim 2, characterized in that: The boron trifluoride derivative is selected from any one or more of boron trifluoride ethyl ether, boron trifluoride ethylamine and boron trifluoride benzylamine.

7. An acrylic emulsion according to claim 2, characterized in that: Terminators are all compounds containing hydroxyl groups, and inhibitors are all compounds that can inhibit free radical polymerization.

8. An acrylic emulsion according to claim 2, characterized in that: The preparation of the non-ionic macromolecular polymer comprises the following steps: putting 20% ​​by mass of hydrogenated bisphenol A resin into a container, adding a vinyl comonomer, heating up, adding a polyether amine, reacting at a constant temperature to obtain a reaction liquid; adding the remaining 80% by mass of hydrogenated bisphenol A resin, polyethylene glycol, acrylamide compound and a polymerization inhibitor into the reaction liquid, heating up, vacuum dehydrating, adding a boron trifluoride derivative, reacting at a constant temperature, adding a terminator, cooling down, discharging, and obtaining the non-ionic macromolecular polymer.

9. The use of an acrylic emulsion according to any one of claims 1 to 8, characterized in that: The acrylic emulsion is applied to a single-component water-based paint or a two-component water-based paint.

10. The method for preparing an acrylic emulsion according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, mixing non-ionic macromolecular polymer, 1% of the total mass of initiator and water, heating to 80-85° C. to obtain a mixed solution; S2, mixing the remaining initiator with the acrylic acid monomer to obtain a mixture; S3, add the mixture to the mixed solution dropwise, complete the addition within 6-8 hours, react at a constant temperature, cool to 40-60°C, add ammonia water and adipic acid dihydrazide, mix, cool, filter, and discharge.

Images