CN115260371A - Water-based industrial paint finish emulsion and preparation method thereof - Google Patents

Abstract

The invention relates to a water-based industrial paint finish emulsion and a preparation method thereof, wherein an anionic emulsifier is selected to be matched with a nonionic emulsifier combination, styrene, an acrylate monomer, a molecular weight regulator and other auxiliaries are polymerized by adopting a seed emulsion and a semi-continuous dropping method, the preparation process is simple, the product is green and environment-friendly, and contains no APEO. Compared with the single-component acrylate emulsion of the common steel structure industrial finish paint, the finish paint emulsion prepared by the invention can effectively improve the early water resistance, fullness and high gloss of the common single-component acrylic emulsion and has strong adhesive force on various metal base materials. Compared with the waterborne secondary dispersion emulsion and the two-component waterborne polyurethane finish paint, the waterborne polyurethane finish paint has obvious cost performance advantage.

Description

Water-based industrial paint finish emulsion and preparation method thereof

Technical Field

The invention relates to the field of industrial paint, in particular to a water-based industrial paint finish emulsion and a preparation method thereof.

Background

With the requirements of national environmental protection policy enhancement and the restriction on VOC emission of manufacturing factories, the selection of water-based raw materials in the industry of industrial paint coating is more strict, and the traditional water-based secondary dispersion can meet the requirements of the current water-based industrial paint of a common steel structure more and more difficultly due to the production and manufacturing cost and the VOC content.

The traditional emulsion polymerized acrylic emulsion has the characteristics of water resistance, high drying speed, weather resistance and the like, is selected by more and more water-based industrial paint manufacturers, but has poor paint film fullness, and always limits the application and popularization in the field of high-gloss high-fullness finish paint. The water-based industrial paint finish emulsion can solve the performance effects of low gloss, early water resistance, adhesion of various base materials such as carbon steel plates, galvanized steel plates, aluminum plates and the like of the prior common single-component water-based acrylic finish, endows the water-based industrial paint with excellent performance indexes, and basically can achieve the performance effect of an oil finish.

Disclosure of Invention

The invention aims to provide a water-based industrial paint finish emulsion and a preparation method thereof, and aims to solve the technical problems.

In order to solve the technical problems, the invention provides the following technical scheme: an aqueous industrial paint emulsion is prepared from the following raw materials in parts by weight: 40-55 parts of water; 1-2.5 parts of anionic emulsifier; 0.1-1 part of nonionic emulsifier; 0.03-0.8 part of initiator; 15-40 parts of styrene; 0.5-3 parts of one or two of methacrylic acid and acrylic acid; 10-20 parts of one or more of butyl acrylate, isooctyl acrylate and methyl methacrylate; 0.01-0.7 part of molecular weight regulator; 0.02-0.1 part of oxidant; 0.01-0.1 part of reducing agent; 0.05-0.7 part of pH buffer; 0.3-1 part of neutralizing agent.

In a preferred embodiment of the present invention, the molecular weight regulator is dodecyl mercaptan or a derivative thereof, and one of primary, secondary and tertiary mercaptans, esters of mercaptans and ethers of mercaptans with 5 to 14 carbon atoms.

As a preferable scheme of the invention, the anionic emulsifier is one or a mixture of more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, ethoxylated sodium alkyl sulfate, sodium alkyl ether sulfate and sodium fatty alcohol ether sulfate.

As a preferable embodiment of the present invention, the oxidizing agent is t-butyl hydroperoxide; the reducing agent is: sodium bisulfite.

As a preferred embodiment of the present invention, the PH buffer is: one or more of sodium bicarbonate, ammonium bicarbonate, ammonia water and ammonium dihydrogen phosphate.

As a preferred embodiment of the present invention, the nonionic emulsifier comprises: one or more of isomeric fatty alcohol ether polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

In a preferred embodiment of the present invention, the initiator solution is one of sodium persulfate, ammonium persulfate, and potassium persulfate.

As a preferred embodiment of the present invention, the neutralizing agent is: one or two of ammonia water and sodium hydroxide.

As a preferable scheme of the invention, the method comprises the following steps:

step one, 1-2 parts of an anionic emulsifier; water: adding 15-30 parts of the mixture into a pre-emulsifying kettle, fully stirring and mixing for 15-25 minutes to completely dissolve the mixture, and then sequentially adding all styrene, acrylate monomers and a molecular weight regulator, stirring at a high speed and emulsifying for 30-40 minutes to prepare a pre-emulsion for later use;

step two, adding 15-30 parts of water, the rest 0.2-1.5 parts of anion and all nonionic emulsifiers and all PH buffering agents into a reaction kettle, starting stirring and heating to 75-90 ℃;

dissolving 0.03-0.1 part of initiator in 1-1.5 parts of water in an oxidation cylinder for later use;

dissolving the rest initiator in 5-10 parts of water in an initiation cylinder for later use;

step five, when the temperature of the reaction kettle rises to 75-90 ℃, quickly adding 10-20% of the pre-emulsifier in the step one into the reaction kettle, and simultaneously adding the initiator solution in the step three, wherein the temperature in the reaction kettle is reduced by 3-5 ℃, after reacting for 15-30 minutes, the liquid at the bottom of the reaction kettle generates obvious blue light, and the temperature in the reaction kettle rises to 82-88 ℃, so as to prepare the seed emulsion;

step six, continuously dropwise adding the pre-emulsified liquid in the remaining step one and the initiator solution in the step four for 2-4 hours, controlling the temperature of the reaction kettle to be 80-90 ℃ for reaction, and gradually increasing the stirring speed along with the rise of the viscosity in the kettle during the dropwise adding process;

seventhly, after all the materials are dripped, keeping the temperature and reacting for 1-2 hours; dissolving an aerobic agent tert-butyl hydroperoxide with 1.5 parts of water, stirring for later use, dissolving a reducing agent sodium bisulfite with 1.5 parts of water, and stirring for later use;

step eight, cooling to 60-70 ℃, adding a prepared tert-butyl hydrogen peroxide aqueous solution, adding a prepared sodium bisulfite aqueous solution after five minutes, carrying out redox elimination reaction, and then carrying out heat preservation reaction for 1 hour after the elimination is finished;

and step nine, after the heat preservation is finished, cooling to below 40 ℃, adding a neutralizing agent solution such as ammonia water and the like, and filtering and discharging to obtain the aqueous industrial paint emulsion.

Compared with the prior art, the invention has the beneficial effects that: adding a molecular weight regulator: dodecyl mercaptan lowers the average molecular weight of the polymer of the industrial paint finish emulsion without much effect on the polymerization rate. Meanwhile, for the free radical polymerization reaction process of the alkadiene, the regulator is added, the molecular weight can be controlled, and a 1,2 structure or a 1,3 structure on a polymer molecular chain can be reduced, so that the hidden troubles of branching, crosslinking and gel generation of the alkadiene are reduced, and the molecular chain is more smooth and compact in arrangement due to a chain structure after emulsion film forming, so that the performances of high glossiness, high fullness, excellent water resistance and the like can be achieved;

a large number of polar groups are brought into the molecular side chain, so that the adhesive force of various metal base materials of a paint film is improved, the hydrophily and lipophilicity of a molecular chain are balanced, and the stability of the emulsion is improved.

Detailed Description

Blank control:

a) Preparing a pre-emulsion: 163g of deionized water and 15g of the anionic emulsifier SDBS are weighed, quickly stirred for 15 minutes to be completely dissolved, 315g of styrene, 175g of butyl acrylate and 10g of acrylic acid are added, and the mixture is stirred at a high speed for 30 minutes to obtain the pre-emulsion.

b) The bottom material was prepared by weighing 197g of deionized water, 4.3g of emulsifier SDBS, 1.5g of isomeric tridecanol nonionic emulsifier S90 (stirred for 15 minutes). And (5) raising the temperature.

c) When the temperature in the kettle rises to 85 ℃, 15% of the pre-emulsion is added into the kettle, 12.1g of ammonium persulfate solution (0.1 g of ammonium persulfate is dissolved by 12g of water) is added, and the reaction is carried out for 20 minutes.

d) The remaining pre-emulsion and 71.25g of ammonium persulfate solution (1.25 g of ammonium persulfate dissolved in 70g of water) were added dropwise over 2 hours at a reaction temperature of 85-90 ℃.

e) After the dropwise addition, the reaction was carried out for 1 hour under heat. The temperature was reduced to 65 ℃ and aqueous tert-butyl hydroperoxide (15 g water dissolved 0.075g tert-butyl hydroperoxide) was added, 10 minutes apart, aqueous sodium bisulfite (15 g water dissolved 0.06g sodium bisulfite) was added and the incubation was completed for 1 hour.

f) And after the heat preservation is finished, cooling to below 40 ℃, adding 5.5g of ammonia water to adjust the pH value to 7-8, filtering through a 200-mesh filter cloth, and discharging to obtain a finished product of the highlight high-fullness industrial finish paint emulsion.

Specific example 1:

a) Preparing a pre-emulsion: 163g of deionized water and 15g of SDBS as an anionic emulsifier are weighed and rapidly stirred for 15 minutes to be completely dissolved, and 310g of styrene, 175g of butyl acrylate, 10g of acrylic acid and 4.3g of dodecyl mercaptan are added and stirred at a high speed for 30 minutes to obtain a pre-emulsion.

b) The bottom material was prepared by weighing 197g of deionized water, 4.3g of emulsifier SDBS, 1.5g of isomeric tridecanol nonionic emulsifier S90 (stirred for 15 minutes). And (5) raising the temperature.

c) When the temperature in the kettle rises to 85 ℃,15 percent of pre-emulsion is added into the kettle, 12.1g of ammonium persulfate solution (0.1 g of ammonium persulfate is dissolved by 12g of water) is added, and the reaction is carried out for 20 minutes.

d) The remaining pre-emulsion and 71.25g of ammonium persulfate solution (1.25 g of ammonium persulfate dissolved in 70g of water) were added dropwise over 2 hours at a reaction temperature of 85-90 ℃.

e) After the completion of the dropwise addition, the reaction was carried out under heat for 1 hour. The temperature was reduced to 65 ℃ and aqueous tert-butyl hydroperoxide (15 g water dissolved 0.075g tert-butyl hydroperoxide) was added, 10 minutes apart, aqueous sodium bisulfite (15 g water dissolved 0.06g sodium bisulfite) was added and the incubation was completed for 1 hour.

f) And after the heat preservation is finished, cooling to below 40 ℃, adding 5.5g of ammonia water to adjust the pH value to 7-8, and filtering and discharging through 200-mesh filter cloth to obtain the finished product of the high-gloss high-fullness industrial paint finish emulsion.

Specific example 2:

a) Preparing a pre-emulsion: 170g and 12g of deionized water, namely SDBS as an anionic emulsifier are weighed and quickly stirred for 15 minutes to be completely dissolved, and 300g of styrene, 185g of butyl acrylate, 10g of methacrylic acid and 4.3g of dodecyl mercaptan are added and stirred at a high speed for 30 minutes to obtain a pre-emulsion.

b) The kettle bottom material was prepared by weighing 190g of deionized water, 4.3g of emulsifier SDBS, 1.5g of isomeric tridecanol nonionic emulsifier and stirring for 15 minutes. And (5) raising the temperature.

c) When the temperature in the kettle rises to 85 ℃,15 percent of pre-emulsion is added into the kettle, 12.1g of ammonium persulfate solution (0.1 g of ammonium persulfate is dissolved by 12g of water) is added, and the reaction is carried out for 20 minutes.

d) The remaining pre-emulsion and 71.25g of ammonium persulfate solution (1.25 g of ammonium persulfate dissolved in 70g of water) were added dropwise over 2 hours at a reaction temperature of 85-90 ℃.

e) After the completion of the dropwise addition, the reaction was carried out under heat for 1 hour. The temperature was reduced to 65 ℃ and aqueous tert-butyl hydroperoxide (15 g water dissolved 0.075g tert-butyl hydroperoxide) was added, 10 minutes apart, aqueous sodium bisulfite (15 g water dissolved 0.06g sodium bisulfite) was added and the incubation was completed for 1 hour.

f) And after the heat preservation is finished, cooling to below 40 ℃, adding 5.5g of ammonia water to adjust the pH value to 7-8, and filtering and discharging through 200-mesh filter cloth to obtain the finished product of the high-gloss high-fullness industrial paint finish emulsion.

Specific example 3:

a) Preparing a pre-emulsion: 163g of deionized water and 15g of an anionic emulsifier SDBS are weighed and rapidly stirred for 15 minutes to be completely dissolved, and 210g of styrene and 90g of methyl methacrylate are added; 105g of isooctyl acrylate, 10g of acrylic acid and 4.3g of dodecyl mercaptan are stirred at a high speed for 30 minutes to obtain the pre-emulsion.

b) The bottom material was prepared by weighing 197g of deionized water, 4.3g of emulsifier SDBS, 1.5g of isomeric tridecanol nonionic emulsifier and stirring for 15 minutes. And (5) raising the temperature.

c) When the temperature in the kettle rises to 85 ℃,15 percent of pre-emulsion is added into the kettle, 12.1g of ammonium persulfate solution (0.1 g of ammonium persulfate is dissolved by 12g of water) is added, and the reaction is carried out for 20 minutes.

d) The remaining pre-emulsion and 71.25g of ammonium persulfate solution (1.25 g of ammonium persulfate dissolved in 70g of water) were added dropwise over 2 hours at a reaction temperature of 85-90 ℃.

e) After the completion of the dropwise addition, the reaction was carried out under heat for 1 hour. The temperature was reduced to 65 ℃ and aqueous tert-butyl hydroperoxide (15 g water dissolved 0.075g tert-butyl hydroperoxide) was added, 10 minutes apart, aqueous sodium bisulfite (15 g water dissolved 0.06g sodium bisulfite) was added and the incubation was completed for 1 hour.

f) And after the heat preservation is finished, cooling to below 40 ℃, adding 5.5g of ammonia water to adjust the pH value to 7-8, and filtering and discharging through 200-mesh filter cloth to obtain the finished product of the high-gloss high-fullness industrial paint finish emulsion.

The following are the basic parameters of the emulsions synthesized by the above examples:

the paint film performance of the water-based industrial paint finish emulsion prepared according to the following paint application formula test method shows that the paint film gloss shows high gloss and fullness at an angle of 20 degrees and an angle of 60 degrees.

By comparing the final paint film test data according to the same paint formula, the paint film prepared by introducing the emulsion of the molecular weight regulator has obviously improved 20-degree and 60-degree angle gloss compared with the paint film of the emulsion without the molecular weight regulator, and has obvious advantages in water resistance, salt water resistance and salt spray resistance.

It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (9)

1. The water-based industrial finish paint emulsion is characterized in that the prepared emulsion comprises the following raw materials in parts by weight: 40-55 parts of water; 1-2.5 parts of anionic emulsifier; 0.1-1 part of nonionic emulsifier; 0.03-0.8 part of initiator; 15-40 parts of styrene; 0.5-3 parts of one or two of methacrylic acid and acrylic acid; 10-20 parts of one or more of butyl acrylate, isooctyl acrylate and methyl methacrylate; 0.01-0.7 part of molecular weight regulator; 0.02-0.1 part of oxidant; 0.01-0.1 part of reducing agent; 0.05-0.7 part of pH buffer; 0.3-1 part of neutralizing agent.

2. The aqueous industrial paint emulsion according to claim 1, wherein the molecular weight regulator is one of dodecyl mercaptan or a derivative thereof, primary, secondary, tertiary mercaptans of 5 to 14 carbon atoms, esters of mercaptans and ethers of mercaptans.

3. The aqueous industrial paint emulsion according to claim 1, wherein the anionic emulsifier is one or more of sodium lauryl sulfate, sodium dodecylbenzene sulfonate, sodium ethoxylated alkyl sulfate, sodium alkyl ether sulfate, sodium fatty alcohol ether sulfate.

4. The aqueous industrial paint emulsion of claim 1 wherein the oxidizing agent is t-butyl hydroperoxide; the reducing agent is: sodium bisulfite.

5. The aqueous industrial paint emulsion of claim 1 wherein the PH buffering agent is: one or more of sodium bicarbonate, ammonium bicarbonate, ammonia water and ammonium dihydrogen phosphate.

6. The aqueous industrial paint emulsion of claim 1 wherein the non-ionic emulsifier comprises: one or more of isomeric fatty alcohol ether polyoxyethylene ether and fatty alcohol polyoxyethylene ether.

7. The aqueous industrial finish emulsion of claim 1, wherein the initiator solution is one of sodium persulfate, ammonium persulfate, and potassium persulfate.

8. The aqueous industrial paint emulsion of claim 1 wherein the neutralizing agent is: one or two of ammonia water and sodium hydroxide.

9. The preparation method of the water-based industrial paint finishing emulsion according to claim 1, which is characterized by comprising the following steps:

step one, 1-2 parts of an anionic emulsifier; water: adding 15-30 parts of the mixture into a pre-emulsifying kettle, fully stirring and mixing for 15-25 minutes to completely dissolve the mixture, and then sequentially adding all styrene, acrylate monomers and a molecular weight regulator, stirring at a high speed and emulsifying for 30-40 minutes to prepare a pre-emulsion for later use;

adding 15-30 parts of water, the rest 0.2-1.5 parts of anion, all nonionic emulsifiers and all PH buffering agents into a reaction kettle, starting stirring and heating to 75-90 ℃;

dissolving 0.03-0.1 part of initiator in 1-1.5 parts of water in an oxidation cylinder for later use;

dissolving the rest initiator in 5-10 parts of water in an initiation cylinder for later use;

step five, when the temperature of the reaction kettle rises to 75-90 ℃, quickly adding 10-20% of the pre-emulsifier in the step one into the reaction kettle, and simultaneously adding the initiator solution in the step three, wherein the temperature in the reaction kettle is reduced by 3-5 ℃, after reacting for 15-30 minutes, the liquid at the bottom of the reaction kettle generates obvious blue light, and the temperature in the reaction kettle rises to 82-88 ℃, so as to prepare the seed emulsion;

step six, continuously dropwise adding the pre-emulsion in the remaining step one and the initiator solution in the step four for 2-4 hours, controlling the temperature of the reaction kettle to be 80-90 ℃ for reaction, and gradually increasing the stirring speed along with the rise of the viscosity in the kettle during the dropwise adding process;

step seven, after all the materials are dripped, keeping the temperature and reacting for 1-2 hours; dissolving an aerobic agent tert-butyl hydroperoxide with 1.5 parts of water, stirring for later use, dissolving a reducing agent sodium bisulfite with 1.5 parts of water, and stirring for later use;

step eight, cooling to 60-70 ℃, adding a prepared tert-butyl hydrogen peroxide aqueous solution, adding a prepared sodium bisulfite aqueous solution after five minutes, carrying out redox elimination reaction, and then carrying out heat preservation reaction for 1 hour after the elimination is finished;

and step nine, after the heat preservation is finished, cooling to below 40 ℃, adding a neutralizing agent solution such as ammonia water and the like, and filtering and discharging to obtain the aqueous industrial paint emulsion.