High-salt-spray-resistance self-drying acrylate emulsion, raw material composition thereof, preparation method and application thereof

Abstract

The invention discloses a high-salt-spray-resistance air-drying acrylate emulsion, a raw material composition thereof, a preparation method and application thereof, and the high-salt-spray-resistance air-drying acrylate emulsion comprises the following components in parts by weight: 480-500 parts of deionized water, 410-460 parts of acrylate and / or styrene monomers, 4-7 parts of polymerizable acrylic phosphate monomers, 3-7 parts of polymerizable ureido monomers and 3-10 parts of modified epoxy resin, 12-20 parts of an emulsifier, 2-4 parts of an initiator, 1-1.4 parts of a buffering agent, 0.5-1 part of an oxidizing agent, 0.3-0.8 part of a reducing agent and 4-6 parts of a neutralizing agent. A coating film of the high-salt-spray-resistance self-drying acrylate emulsion prepared by the preparation method has excellent salt spray resistance, relatively good adhesive force and impact resistance and relatively good stability.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a highly salt-fog-resistant self-drying acrylic emulsion, a raw material composition thereof, and a preparation method and application thereof. Background Art

[0002] As environmental regulations restrict VOC content in coatings more and more strictly, low-VOC coating resins are increasingly used. Acrylic emulsions, due to their water-based solvent characteristics, have very low VOC content, and their applications have expanded from architectural coatings to industrial paints. However, since the film-forming mechanism of self-drying acrylic emulsion coatings is generally ordinary physical drying latex particles stacking film, the final paint film density is relatively general, resulting in gaps between particles, and the salt spray resistance and anti-corrosion effect is greatly reduced.

[0003] In the prior art, CN117430761A mentions an epoxy resin modified acrylic emulsion and a preparation method, including a pre-emulsified liquid material, a kettle bottom material and other small materials. According to the mass fraction, the pre-emulsified liquid material contains: water, anionic emulsifier, nonionic emulsifier, phosphate emulsifier, styrene, butyl acrylate, methyl methacrylate, epoxy resin, acrylamide, silane coupling agent, the kettle bottom material contains: water, anionic emulsifier, nonionic emulsifier, reactive emulsifier and sodium bicarbonate, and the small materials contain initiator, oxidant, reducing agent and water. Epoxy resin and acrylic resin are used for hybrid polymerization, and then they are matched with water-based epoxy curing agent through external crosslinking to give the coating excellent salt spray resistance, good adhesion and impact resistance. However, the introduction of epoxy resin into acrylic emulsion has poor compatibility and poor stability. The epoxy resin is easily precipitated after long-term storage, and even causes emulsion stratification. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a highly salt-fog-resistant self-drying acrylic emulsion, a raw material composition, a preparation method and an application thereof. The highly salt-fog-resistant self-drying acrylic emulsion of the present invention can improve the adhesion between the coating and the substrate in the paint film of the steel structure coating, thereby greatly improving its salt-fog-resistant and corrosion-resistant effects.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] In one aspect, the present invention provides a raw material composition of a highly salt-fog-resistant self-drying acrylic emulsion, which comprises the following components in parts by weight:

[0007] 480-500 parts of deionized water, 410-460 parts of acrylate and / or styrene monomers, 4-7 parts of polymerizable acrylic phosphate monomers, 3-7 parts of polymerizable urea monomers, 3-10 parts of modified epoxy resin, 12-20 parts of emulsifier, 2-4 parts of initiator, 1-1.4 parts of buffer, 0.5-1 part of oxidant, 0.3-0.8 part of reducing agent and 4-6 parts of neutralizer.

[0008] In some embodiments, the acrylic acid ester and / or styrene monomer is selected from a plurality of monomers selected from styrene, n-butyl acrylate, methyl methacrylate, ethyl acrylate, isooctyl methacrylate, isooctyl acrylate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, ethylene urea ethoxy methacrylate, and acrylic acid phosphate monomers;

[0009] In some embodiments, the polymerizable acrylic acid phosphate monomer includes PAM100 and / or PAM200;

[0010] In some embodiments, the polymerizable urea-based monomer includes MEEU50W and / or WAM-Ⅱ;

[0011] In some embodiments, the modified epoxy resin is prepared by addition reaction of epoxy resin, acrylic acid, hydroquinone and triphenylphosphine; wherein the molar ratio of epoxy functional group of epoxy resin to acrylic acid is 1.8-2.2:1, hydroquinone accounts for 1 / 1000 of the total mass of epoxy resin and acrylic acid, and triphenylphosphine accounts for 5 / 1000 of the total mass of epoxy resin and acrylic acid;

[0012] In some preferred embodiments, the epoxy resin is selected from at least one of bisphenol A epoxy resins E51, E44, and E20.

[0013] In some embodiments, the emulsifier is an anionic emulsifier and / or a nonionic emulsifier;

[0014] In some preferred embodiments, the anionic emulsifier is selected from at least one of fatty alcohol polyoxyethylene ether sulfate, alkyl sulfate and alkyl alcohol ether succinic acid;

[0015] In some preferred embodiments, the nonionic emulsifier includes fatty alcohol polyoxyethylene ethers.

[0016] In some embodiments, the initiator is a persulfate compound, including at least one of ammonium persulfate and potassium persulfate;

[0017] In some embodiments, the buffer is selected from at least one of sodium bicarbonate, ammonium bicarbonate, sodium dihydrogen phosphate, and ammonia water;

[0018] In some embodiments, the oxidant is selected from at least one of hydrogen peroxide and tert-butyl hydroperoxide;

[0019] In some embodiments, the reducing agent is selected from at least one of sodium bisulfite, sodium formaldehyde sulfoxylate, ascorbic acid, and isoascorbic acid;

[0020] In some embodiments, the neutralizing agent is selected from at least one of aqueous ammonia, dimethylethanolamine, 2-amino-2-methyl-1-propanol, sodium hydroxide, and potassium hydroxide.

[0021] In another aspect, the present invention provides a method for preparing a highly salt spray resistant self-drying acrylic emulsion, comprising at least:

[0022] (1) Preparation of pre-emulsion: Add deionized water and part of the emulsifier into a pre-emulsification kettle, stir, and slowly add acrylic acid ester and / or styrene monomers to modify epoxy resin after dissolving and stirring at high speed for 30 to 60 minutes to obtain a pre-emulsion;

[0023] (2) Add deionized water, buffer, and remaining emulsifier into the reaction kettle, stir, and heat to 80-90° C.;

[0024] (3) When the temperature of the reactor is stabilized at 80-90° C., 3-10% of the pre-emulsion is added, and at the same time, an initial initiator is added to carry out an initial reaction;

[0025] (4) simultaneously dropping the remaining pre-emulsion and the initiator into the reactor at a uniform speed, and after the dropping process lasts for 2 hours, adding the polymerizable acrylic acid phosphate monomer and the polymerizable urea monomer to the remaining pre-emulsion and stirring evenly, and continuously dropping until all the materials have been dropped, the total dropping time is 3 to 3.5 hours, the dropping temperature is 80 to 90° C., and after the dropping is completed, heat preservation treatment is performed;

[0026] (5) The temperature of the reactor is lowered to 55-75°C, and the oxidant and the reductant are added dropwise at the same time. The addition time is 30 minutes, and the temperature is maintained at 55-75°C. After the addition is completed, the reactor is kept warm;

[0027] (6) After the heat preservation is completed, the temperature is rapidly lowered to below 40° C., a neutralizing agent is added to adjust the pH to 7-9, and the mixture is filtered and discharged to obtain the highly salt spray resistant self-drying acrylic emulsion.

[0028] In step (1), the amount of deionized water used is 170 to 190 parts;

[0029] In step (1), the amount of the partial emulsifier is 6 to 9 parts;

[0030] In step (1), the rotation speed of the high-speed stirring is 400-500 r / min;

[0031] In step (2), the amount of deionized water used is 250 to 270 parts;

[0032] In step (2), the heating temperature is 82-86° C.;

[0033] In step (3), the temperature of the reactor is 82-86°C;

[0034] In step (3), the amount of the initial initiator is 0.5 to 1.0 parts;

[0035] In step (3), the initial reaction time is 10 to 15 minutes;

[0036] In step (4), the amount of the initiator added dropwise is 1.3 to 1.9 parts;

[0037] In step (4), the dropping temperature is 82-86°C;

[0038] In step (4), the heat preservation treatment time is 1.5 to 2 hours;

[0039] In step (4), the temperature of the heat preservation treatment is 84-88°C;

[0040] In step (5), the temperature of the reactor is reduced to 65-75°C;

[0041] In step (5), the temperature of the dropping is 65 to 75° C.;

[0042] In step (5), the heat preservation treatment time is 30 to 60 minutes;

[0043] In step (5), the temperature of the heat preservation treatment is 55 to 75°C, preferably 65 to 75°C.

[0044] The initial initiator is added in the form of an aqueous solution, preferably, the initial initiator is dissolved in 7 to 10 parts of deionized water;

[0045] The dropwise initiator is added in the form of an aqueous solution, preferably, the dropwise initiator is dissolved in 12 to 15 parts of deionized water;

[0046] The reducing agent is added in the form of an aqueous solution, preferably, the reducing agent is dissolved in 11 to 14 parts of deionized water;

[0047] The oxidant is added in the form of an aqueous solution. Preferably, the oxidant is dissolved in 11 to 14 parts of deionized water.

[0048] The preparation method of the modified epoxy resin comprises: adding epoxy resin, acrylic acid and hydroquinone into a reaction bottle, starting stirring, heating to 100° C., adding triphenylphosphine, reacting for 3 hours, and cooling down.

[0049] The third aspect of the present invention further provides a highly salt-fog-resistant self-drying acrylic emulsion, which is prepared by the above-mentioned preparation method of the highly salt-fog-resistant self-drying acrylic emulsion.

[0050] In some embodiments, the solid content of the emulsion is 45-47%, the pH is 7-9, the viscosity is 1500-5000 mPa.s, the theoretical glass transition temperature of the polymer is 30°C-60°C, and the minimum film-forming temperature is 20-45°C.

[0051] The fourth aspect of the present invention also provides an application of the above-mentioned highly salt spray resistant self-drying acrylic emulsion in the field of coatings.

[0052] The reagents and raw materials used in the present invention are commercially available.

[0053] The positive and progressive effects of the present invention are:

[0054] The present invention adds polymerizable modified epoxy resin, acrylic acid phosphate monomer and polymerizable urea monomer, not only the hydrophobic section of the polymer inner layer introduces epoxy resin to improve the adhesion to the metal substrate, but also the hydrophilic section of the outer layer of the polymer particles introduces more phosphate groups and urea monomers, so that after the polymer paint film dries, it can better adhere to the steel substrate, and further passivate the steel substrate, thereby improving the corrosion resistance of the steel. Compared with the acrylic acid self-drying water-based paint without adding such substances, the high salt spray resistance self-drying acrylic acid emulsion paint prepared by the present invention has more obvious salt spray resistance and anti-corrosion performance. DETAILED DESCRIPTION

[0055] The present invention is described in detail below in conjunction with the embodiments, and the technical scheme of the present invention is clearly and completely described to facilitate the understanding of the present invention by those skilled in the art. The described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. At the same time, the raw materials mentioned below that are not described in detail are all commercially available products; the process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0056] Example 1

[0057] I. Synthesis of epoxy-modified monomers, specifically comprising the following steps:

[0058] 100 g of epoxy resin E51, 18 g of acrylic acid, and 0.12 g of hydroquinone were added into a three-necked flask, and stirring was started. The temperature was raised to 100°C, and 0.59 g of triphenylphosphine was added. The mixture was reacted for 3 h, and the temperature was lowered for later use.

[0059] II. A method for preparing a highly salt spray resistant self-drying acrylic emulsion, comprising the following steps:

[0060] S1, preparation of pre-emulsion: weigh 180g of deionized water and 7.0g of anionic emulsifier sodium dodecyl sulfate, put them into a pre-emulsification bottle, stir and dissolve until transparent; then add 8.2g of acrylamide, 7.0g of acrylic acid, 257.6g of styrene (dissolved modified epoxy resin 5g), 88.6g of n-butyl acrylate, 79.1g of isooctyl acrylate in sequence, increase the speed to 420r / min, and disperse at high speed for 30min to obtain a pre-emulsion;

[0061] S2. Preparation of dropwise initiator solution: accurately weigh and add 13.4 g of deionized water into the initiator tank, and then add 1.55 g of potassium persulfate to fully dissolve for later use;

[0062] S3, preparation of initial initiator solution: add 8g of deionized water into a container, then add 0.8g of potassium persulfate, stir to fully dissolve and set aside;

[0063] S4, add 261g of deionized water, 1.2g of sodium bicarbonate buffer, 7.6g of anionic emulsifier sodium dodecyl sulfate, and 1.7g of nonionic emulsifier OP-10 into the reactor, start stirring and heat to 82-86°C;

[0064] S5. When the temperature of the reactor is stabilized at 82-85°C, 50 g of the pre-emulsion prepared in step S1 is added to the reactor, and the initial initiator aqueous solution prepared in step S3 is added at the same time;

[0065] S6, react in the kettle for 10 minutes, after the temperature stabilizes at 82-86°C, uniformly add the remaining pre-emulsion and the initiator solution prepared in step S2, the addition time is 3 hours;

[0066] S7. After the dropping process lasts for 2 hours, 4.5 g of polymerizable acrylic acid phosphate monomer PAM100 and 4.8 g of polymerizable urea monomer MEEU50W are added to the remaining pre-emulsion, and stirred evenly;

[0067] S8, continue to drip until all the pre-emulsion and initiator solution are added, keep warm for 1.5 hours, and control the insulation temperature at 85-88°C;

[0068] S9. During the heat preservation process, 13 g of water and 0.74 g of tert-butyl peroxide hydrogen hydration agent were added to a container, stirred evenly, and an oxidant solution was prepared; 13 g of water was weighed in another container and 0.52 g of sodium bisulfite reducing agent was added, stirred evenly, and a reducing agent solution was prepared;

[0069] S10, after the insulation is completed, the temperature in the reactor is quickly reduced to 60°C;

[0070] S11, dripping the oxidant aqueous solution and the reducing agent aqueous solution prepared in step S9, the dripping time is 30 minutes, and the temperature is maintained at 60°C;

[0071] S12, after the addition is completed, keep warm at 60°C for 30 minutes;

[0072] S13, after the heat preservation is completed, the temperature is quickly lowered to below 40°C, 5.0 g of ammonia water as a neutralizing agent is slowly added, and the pH of the emulsion in the kettle is adjusted to 7-9;

[0073] S14. After adjusting the pH value of the emulsion, filter the material to obtain a highly salt spray resistant self-drying acrylic emulsion.

[0074] Example 2

[0075] I. Synthesis of epoxy-modified monomers, specifically comprising the following steps:

[0076] 100 g of epoxy resin E44, 15 g of acrylic acid, and 0.12 g of hydroquinone were added into a three-necked flask, and stirring was started. The temperature was raised to 100°C, and 0.58 g of triphenylphosphine was added. The mixture was reacted for 3 h, and the temperature was lowered for later use.

[0077] II. A method for preparing a highly salt spray resistant self-drying acrylic emulsion, comprising the following steps:

[0078] S1, preparation of pre-emulsion: 188g of deionized water and 8.2g of anionic emulsifier 2A1 were put into a pre-emulsification bottle, stirred at 210r / min, and dissolved until transparent; then 7.5g of acrylamide, 6.4g of acrylic acid, 252.6g of styrene (10g of modified epoxy was dissolved), 86.2g of n-butyl acrylate, and 82.9g of isooctyl acrylate were added in sequence, the speed was increased to 420r / min, and high-speed dispersion was performed for 30min to obtain a pre-emulsion;

[0079] S2. Preparation of initiator solution: 12.6 g of deionized water, add 1.82 g of ammonium persulfate and fully dissolve for later use;

[0080] S3, preparation of initial initiator solution: 8.3g of deionized water, 0.75g of ammonium persulfate, fully dissolved for later use;

[0081] S4, add 257.4g deionized water, 1.03g buffer sodium bicarbonate, 7.8g anionic emulsifier 2A1, 2.4g nonionic emulsifier NP-10 into the reactor, start stirring at 160r / min, and heat to 83-86°C;

[0082] S5. At a temperature of 83-86°C, take 54 g of the pre-emulsion prepared in step S1 and add it directly into the reaction kettle. At the same time, add the initial initiator aqueous solution prepared in step S3.

[0083] S6, react in the kettle for 15 minutes, and at the same time, uniformly add the remaining pre-emulsified liquid core initiator solution prepared in step S2, the temperature is controlled at 83-86°C, and the addition time is 3.5 hours;

[0084] S7. After 2 hours of dropwise addition, add 4.5 g of polymerizable acrylic acid phosphate monomer PAM200 and 4.2 g of polymerizable urea monomer WAM-Ⅱ to the remaining pre-emulsion and stir evenly;

[0085] S8, continue to drip until all the pre-emulsion and initiator solution are added, keep warm for 2 hours, and control the insulation temperature at 84-86°C;

[0086] S9, during the heat preservation process, 12.9g water and 0.83g tert-butyl hydrogen peroxide hydrogenation agent, stir evenly, and prepare an oxidant solution for standby use; 12.9g water and 0.45g sodium bisulfite reducing agent, stir evenly, and prepare a reducing agent solution for standby use;

[0087] S10, after the heat preservation is completed, the temperature is lowered to 65°C;

[0088] S11, after the temperature drops to the above range, the oxidant aqueous solution and the reducing agent aqueous solution prepared in step S9 are added dropwise at the same time, the addition time is 30 minutes, and the temperature is maintained at 65°C;

[0089] S12, after the addition is completed, keep warm at 65°C for 60 minutes;

[0090] S13, after the heat preservation is completed, the temperature is lowered to below 40°C, 4.8g of ammonia water as a neutralizing agent is added, and the pH value of the emulsion is adjusted to 7-9;

[0091] S14. After adjusting the pH value of the emulsion, filter the material to obtain a highly salt spray resistant self-drying acrylic emulsion.

[0092] Example 3

[0093] I. Synthesis of epoxy-modified monomers, specifically comprising the following steps:

[0094] Add 100g of epoxy resin E20, 7g of acrylic acid, and 0.11g of hydroquinone into a three-necked flask, start stirring, raise the temperature to 100°C, add 0.54g of triphenylphosphine, react for 3h, and cool for later use.

[0095] II. A method for preparing a highly salt spray resistant self-drying acrylic emulsion, comprising the following steps:

[0096] S1, preparation of pre-emulsion: 180g of deionized water and 7.8g of anionic emulsifier SR-10 were put into a pre-emulsification bottle and stirred evenly; then 7.1g of acrylamide, 7.2g of acrylic acid, 257.6g of styrene (5g of dissolved modified epoxy resin), 90.2g of n-butyl acrylate, and 78.9g of isooctyl acrylate were added in sequence, the speed was increased to 500r / min, and high-speed dispersion was performed for 30min to obtain a pre-emulsion;

[0097] S2. Preparation of initiator solution: 1.75 g of ammonium persulfate was added to 13 g of deionized water and fully dissolved for later use;

[0098] S3, preparation of initial initiator solution: add 0.8g of ammonium persulfate to 7g of deionized water and fully dissolve for later use;

[0099] S4, add 259.4g deionized water, 1.03g buffer sodium bicarbonate, 7.9g anionic emulsifier SR-10, 2.5g nonionic emulsifier ER-10 into the reactor, start stirring, start heating, and heat to 82-86°C;

[0100] S5. When the temperature of the reactor is 82-86°C, take 52 g of the pre-emulsion prepared in step S1 and add it directly into the reactor, and at the same time add the initial initiator aqueous solution prepared in step S3;

[0101] S6, react in the kettle for 12 minutes, after the temperature reaches 82-86°C, add the remaining pre-emulsion and the initiator solution prepared in step S2 at a uniform speed, control the temperature at 82-86°C, and add for 3 hours;

[0102] S7, when the dropping process lasts for 2 hours, add all 4.1g of polymerizable acrylic acid phosphate monomer PAM200 and 4.7g of polymerizable urea monomer MEEU50W to the remaining pre-emulsion, and stir evenly;

[0103] S8, continue to drip until all the pre-emulsion and initiator solution are added, keep warm for 1.5 hours, and control the insulation temperature at 84-88°C;

[0104] S9, during the heat preservation process, 11g of water and 0.88g of tert-butyl hydrogen peroxide hydrogen oxidizing agent are stirred evenly to prepare an oxidizing agent solution for standby use; 11g of water is added with 0.58g of sodium bisulfite reducing agent, stirred evenly, and a reducing agent solution is prepared for standby use;

[0105] S10, after the heat preservation is completed, the temperature is lowered to 75°C;

[0106] S11, after the temperature drops to the above range, the oxidant aqueous solution and the reducing agent aqueous solution prepared in step S9 are added dropwise at the same time, the addition time is 30 minutes, and the temperature is maintained at 75°C;

[0107] S12, after the addition is completed, keep warm at 75°C for 50 minutes;

[0108] S13, after the heat preservation is completed, the temperature is quickly lowered to below 40°C, 4.5g of ammonia water as a neutralizing agent is slowly added, and the pH of the emulsion in the kettle is adjusted to 7-9;

[0109] S14. After adjusting the pH value of the emulsion, filter the material to obtain a highly salt spray resistant self-drying acrylic emulsion.

[0110] The present invention also provides the following comparative examples.

[0111] Comparative Example 1

[0112] The only difference from Example 1 is that no epoxy-modified monomer is added and step S7 is omitted.

[0113] Comparative Example 2

[0114] The only difference from Example 1 is that the added epoxy resin is not modified.

[0115] Comparative Example 3

[0116] I. Synthesis of epoxy-modified monomers, specifically comprising the following steps:

[0117] 100 g of epoxy resin E51, 36 g of acrylic acid, and 0.12 g of hydroquinone were added into a three-necked flask, and stirring was started. The temperature was raised to 100°C, and 0.59 g of triphenylphosphine was added. The mixture was reacted for 3 h, and the temperature was lowered for later use.

[0118] II. The only difference from Example 1 is that the modified epoxy monomer added is different. A large amount of slag appears during the preparation process, and the preparation process cannot be completed.

[0119] Product performance testing

[0120] (1) Emulsion performance data

[0121] The emulsions prepared in the examples and comparative examples were tested, and the test standards or methods were as follows:

[0122] 1. Solid content: carried out by the method specified in GB / T 20623-2006.

[0123] 2. Emulsion particle size: tested by Malvern laser particle size analyzer.

[0124] 3. Viscosity test: carried out by the rotational viscometer method in GB / T 2794-1995.

[0125] 4. pH value: The pH value is measured by the method specified in GB / T 20623-2006 when the emulsion is heated to 23±2℃.

[0126] 5. Hot storage test: Take 100g of emulsion into a sample bottle, put it into a constant temperature oven, and place it at 50℃ for 7 days to observe the state of the emulsion.

[0127] The basic test data of the emulsions prepared in the above examples and comparative examples are shown in Table 1.

[0128] Table 1 Basic parameters test data of emulsion

[0129]

[0130] (2) Preparation of coating

[0131] The emulsions prepared in the above examples and comparative examples were prepared according to the formula shown in Table 2 and the following steps to obtain a water-based industrial paint steel structure topcoat coating:

[0132] Step 1: Add materials 1, 2, 3 and 4 in sequence and stir evenly at low speed;

[0133] Step 2: Add materials 5, 6 and 7 in sequence and grind at high speed to a fineness of less than 30 μm;

[0134] Step 3: Add substances 8 to 15 in sequence, stir for 10 minutes, adjust the viscosity to 90±5KU, filter the material, and prepare the coating.

[0135] Table 2 Raw materials for preparation of water-based industrial paint steel structure topcoat coating

[0136]

[0137]

[0138] (3) Conditions for coating film performance testing

[0139] a) Substrate: polished carbon steel plate and tinplate;

[0140] b) Coating preparation: spraying with spray gun;

[0141] c) Coating preparation and curing conditions: dry film 55-65μm, curing for 7 days under standard conditions.

[0142] (4) Testing methods and standards for coating film performance

[0143] Table 3 Performance test related standards

[0144] Test items Implementation Standards Film thickness / μm GB / T13452.2 Impact resistance test (cm) GB / T1732-1993 Pencil hardness (scratch) GB / T6739-2006 Adhesion test (cross cut) GB / T9286-1998 Water resistance test GB / T1732-1993 Salt water resistance test (3% NaCl aqueous solution) GB / T9274-1988 Salt spray resistance test GB / T1771-2007

[0145] (5) Paint film performance test results

[0146] The test results of the coating film properties prepared from the emulsions prepared in the above examples and comparative examples are shown in Table 4.

[0147] Table 4 Performance test results of different paint films

[0148]

[0149]

[0150] Through the comparison of the final paint film test data above, the paint film made by introducing the emulsion prepared by polymerizable modified epoxy resin, acrylic phosphate monomer and polymerizable urea-based monomer has significantly improved water resistance, salt water resistance and salt spray resistance compared with the emulsion film prepared without adding these two types of materials, thus proving that this type of self-drying acrylic emulsion has excellent anti-corrosion properties.

[0151] Finally, it should be noted that in the present invention, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0152] Although the present disclosure has been disclosed above through the description of the specific embodiments of the present disclosure, it should be understood that those skilled in the art can design various modifications, improvements or equivalents to the present disclosure within the spirit and scope of the attached scheme. These modifications, improvements or equivalents should also be considered to be included in the scope of protection claimed by the present disclosure.

Claims

1. A raw material composition of a highly salt-spray-resistant self-drying acrylic emulsion, characterized in that: It includes the following components in parts by weight: 480-500 parts of deionized water, 410-460 parts of acrylate and / or styrene monomers, 4-7 parts of polymerizable acrylic phosphate monomers, 3-7 parts of polymerizable urea monomers, 3-10 parts of modified epoxy resin, 12-20 parts of emulsifier, 2-4 parts of initiator, 1-1.4 parts of buffer, 0.5-1 part of oxidant, 0.3-0.8 part of reducing agent and 4-6 parts of neutralizer.

2. The raw material composition of the highly salt-fog resistant self-drying acrylic emulsion according to claim 1, characterized in that: The acrylic acid ester and / or styrene monomers are selected from a plurality of monomers selected from styrene, n-butyl acrylate, methyl methacrylate, ethyl acrylate, isooctyl methacrylate, isooctyl acrylate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, ethylene urea ethoxy methacrylate, and acrylic acid phosphate monomers; and / or, the polymerizable acrylic phosphate monomer comprises PAM100 and / or PAM200; and / or, the polymerizable urea-based monomer comprises MEEU50W and / or WAM-Ⅱ; And / or, the modified epoxy resin is prepared by addition reaction of epoxy resin, acrylic acid, hydroquinone and triphenylphosphine; wherein the molar ratio of epoxy functional group of epoxy resin to acrylic acid is 1.8-2.2:1, hydroquinone accounts for 1 / 1000 of the total mass of epoxy resin and acrylic acid, and triphenylphosphine accounts for 5 / 1000 of the total mass of epoxy resin and acrylic acid; And / or, the emulsifier is an anionic emulsifier and / or a nonionic emulsifier; And / or, the initiator is a persulfate compound, including at least one of ammonium persulfate and potassium persulfate; And / or, the buffer is selected from at least one of sodium bicarbonate, ammonium bicarbonate, sodium dihydrogen phosphate, and ammonia water; And / or, the oxidant is selected from at least one of hydrogen peroxide and tert-butyl hydroperoxide; And / or, the reducing agent is selected from at least one of sodium bisulfite, sodium formaldehyde sulfoxylate, ascorbic acid, and isoascorbic acid; And / or, the neutralizing agent is selected from at least one of aqueous ammonia, dimethylethanolamine, 2-amino-2-methyl-1-propanol, sodium hydroxide and potassium hydroxide.

3. The raw material composition of the highly salt-fog resistant self-drying acrylic emulsion according to claim 2, characterized in that: The anionic emulsifier is selected from at least one of fatty alcohol polyoxyethylene ether sulfate, alkyl sulfate and alkyl alcohol ether succinic acid; And / or, the nonionic emulsifier includes fatty alcohol polyoxyethylene ether; And / or, the epoxy resin is selected from at least one of bisphenol A epoxy resins E51, E44, and E20.

4. A method for preparing a highly salt spray resistant self-drying acrylic emulsion, characterized in that: The raw materials of the highly salt-fog-resistant self-drying acrylic emulsion include the raw material composition of the highly salt-fog-resistant self-drying acrylic emulsion according to any one of claims 1 to 3, and the method includes the following steps: (1) Preparation of pre-emulsion: Add deionized water and part of the emulsifier into a pre-emulsification kettle, stir, and slowly add acrylic acid ester and / or styrene monomers to modify epoxy resin after dissolving and stirring at high speed for 30 to 60 minutes to obtain a pre-emulsion; (2) Add deionized water, buffer, and remaining emulsifier into the reaction kettle, stir, and heat to 80-90° C.; (3) When the temperature of the reactor is stabilized at 80-90° C., 3-10% of the pre-emulsion is added, and at the same time, an initial initiator is added to carry out an initial reaction; (4) simultaneously dropping the remaining pre-emulsion and the initiator into the reactor at a uniform speed, and after the dropping process lasts for 2 hours, adding the polymerizable acrylic acid phosphate monomer and the polymerizable urea monomer to the remaining pre-emulsion and stirring evenly, and continuously dropping until all the materials have been dropped, the total dropping time is 3 to 3.5 hours, the dropping temperature is 80 to 90° C., and after the dropping is completed, heat preservation treatment is performed; (5) The temperature of the reactor is lowered to 55-75°C, and the oxidant and the reductant are added dropwise at the same time. The addition time is 30 minutes, and the temperature is maintained at 55-75°C. After the addition is completed, the reactor is kept warm; (6) After the heat preservation is completed, the temperature is rapidly lowered to below 40° C., a neutralizing agent is added to adjust the pH to 7-9, and the mixture is filtered and discharged to obtain the highly salt spray resistant self-drying acrylic emulsion.

5. The method for preparing the highly salt-fog resistant self-drying acrylic emulsion according to claim 4, characterized in that: The preparation method satisfies at least one of the following conditions: In step (1), the amount of deionized water used is 170 to 190 parts; In step (1), the amount of the partial emulsifier is 6 to 9 parts; In step (1), the rotation speed of the high-speed stirring is 400-500 r / min; In step (2), the amount of deionized water used is 250 to 270 parts; In step (2), the heating temperature is 82-86° C.; In step (3), the temperature of the reactor is 82-86°C; In step (3), the amount of the initial initiator is 0.5 to 1.0 parts; In step (3), the initial reaction time is 10 to 15 minutes; In step (4), the amount of the initiator added dropwise is 1.3 to 1.9 parts; In step (4), the dropping temperature is 82-86°C; In step (4), the heat preservation treatment time is 1.5 to 2 hours; In step (4), the temperature of the heat preservation treatment is 84-88°C; In step (5), the temperature of the reactor is reduced to 65-75°C; In step (5), the temperature of the dropwise addition is 65 to 75° C.; In step (5), the heat preservation treatment time is 30 to 60 minutes; In step (5), the temperature of the heat preservation treatment is 55 to 75°C, preferably 65 to 75°C.

6. The method for preparing the highly salt-fog resistant self-drying acrylic emulsion according to claim 4, characterized in that: The preparation method satisfies at least one of the following conditions: The initial initiator is added in the form of an aqueous solution, preferably, the initial initiator is dissolved in 7 to 10 parts of deionized water; The dropwise initiator is added in the form of an aqueous solution, preferably, the dropwise initiator is dissolved in 12 to 15 parts of deionized water; The reducing agent is added in the form of an aqueous solution, preferably, the reducing agent is dissolved in 11 to 14 parts of deionized water; The oxidant is added in the form of an aqueous solution. Preferably, the oxidant is dissolved in 11 to 14 parts of deionized water.

7. The method for preparing the highly salt-fog resistant self-drying acrylic emulsion according to claim 4, characterized in that: The preparation method of the modified epoxy resin comprises: adding epoxy resin, acrylic acid and hydroquinone into a reaction bottle, starting stirring, heating to 100° C., adding triphenylphosphine, reacting for 3 hours, and cooling down.

8. A highly salt spray resistant self-drying acrylic emulsion, characterized in that: The invention is prepared by the method for preparing the highly salt spray resistant self-drying acrylic emulsion as claimed in any one of claims 4 to 7.

9. The highly salt-spray-resistant self-drying acrylic emulsion according to claim 8, characterized in that: The solid content of the emulsion is 45-47%, the pH is 7-9, the viscosity is 1500-5000 mPa.s, the theoretical glass transition temperature of the polymer is 30-60°C, and the minimum film-forming temperature is 20-45°C.

10. Use of the highly salt spray resistant self-drying acrylic emulsion according to claim 8 in the field of coatings.

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