阅读说明：本技术 一种水性丙烯酸荧光涂料及其制备方法 (Water-based acrylic fluorescent paint and preparation method thereof ) 是由 黄映恒 何灿 农毅 梁瑶莹 王露甲 王智军 勾玖均 李燕 于 2019-11-01 设计创作，主要内容包括：本发明提供了一种水性丙烯酸荧光涂料及其制备方法,所述制备方法包括以下步骤：制备二氧化硅包覆改性荧光粉；在得到的二氧化硅包覆改性荧光粉加入到水性溶剂中搅拌得到改性荧光粉悬浊液,将改性荧光粉悬浊液加入到包含丙烯酸酯单体的乳液中,并加入引发剂进行反应,调节pH值为6.5-7.5,得到稳定的纳米SiO<Sub>2</Sub>/丙烯酸酯复合乳液；乳液B的成分包括甲基丙烯酸甲酯,乳液C的成分包括丙烯酸正丁酯；将得到的纳米SiO<Sub>2</Sub>/丙烯酸酯复合乳液与固化剂、助剂混合均匀,得到水性丙烯酸荧光涂料。本发明的技术方案采用二氧化硅包覆改性荧光粉,用改性后的荧光粉做核,丙烯酸酯共聚物为壳,既增强了荧光粉的发光性能,又提高乳液的稳定性。(The invention provides a water-based acrylic fluorescent paint and a preparation method thereof, wherein the preparation method comprises the following steps: preparing silicon dioxide coated modified fluorescent powder; adding the obtained silicon dioxide coated modified fluorescent powder into an aqueous solvent, stirring to obtain a modified fluorescent powder suspension, adding the modified fluorescent powder suspension into an emulsion containing an acrylate monomer, adding an initiator for reaction, and adjusting the pH value to 6.5-7.5 to obtain stable nano SiO 2 Acrylate composite emulsion; the component of the emulsion B comprises methyl methacrylate, and the component of the emulsion C comprises n-butyl acrylate; the obtained nano SiO 2 The acrylate composite emulsion is evenly mixed with the curing agent and the auxiliary agent to obtain the water-basedAcrylic acid fluorescent paint. According to the technical scheme, the modified fluorescent powder is coated by silicon dioxide, the modified fluorescent powder is used as a core, and the acrylate copolymer is used as a shell, so that the luminous performance of the fluorescent powder is enhanced, and the stability of the emulsion is improved.)

1. A preparation method of a water-based acrylic fluorescent paint is characterized by comprising the following steps: which comprises the following steps:

step S1, preparing silicon dioxide coated modified fluorescent powder;

step S2, adding the obtained silicon dioxide coated modified fluorescent powder into an aqueous solvent, stirring to obtain a modified fluorescent powder suspension, adding the modified fluorescent powder suspension into an emulsion containing an acrylate monomer, adding an initiator for reaction, and adjusting the pH value to 6.5-7.5 to obtain stable nano SiO₂Acrylate composite emulsion;

wherein the components of the emulsion B comprise methyl methacrylate; the components of the emulsion C comprise n-butyl acrylate;

step S3, the nano SiO obtained in step S2₂And uniformly mixing the acrylate composite emulsion with a curing agent and an auxiliary agent to obtain the water-based acrylic fluorescent paint.

2. The method for preparing the water-based acrylic fluorescent paint according to claim 1, characterized in that: in step S1, a sol-gel method is used to prepare the silica gel-coated phosphor, and then the silica gel-coated phosphor is obtained by calcining and cooling.

3. The preparation method of the water-based acrylic fluorescent paint as claimed in claim 2, wherein the silica-coated modified phosphor is prepared by dissolving tetraethoxysilane in ethanol solution, adjusting pH to 3 ~ 4, heating and stirring at 40 ~ 60 ℃ to obtain transparent sol, immersing the phosphor in the sol, stirring at 50 ~ 100 ℃ for 40 ~ 60min, adjusting pH to 6 ~ 7, standing for complete gelation, finally drying in an oven at 60 ~ 100 ℃ and 100 ℃, calcining at 400 ~ 500 ℃ for 2 ~ 4 hours, cooling and grinding.

4. The preparation method of the water-based acrylic fluorescent paint as claimed in claim 3, wherein the mass ratio of the ethyl orthosilicate to the fluorescent powder is 1:1 ~ 3, and the nano SiO is₂In the acrylate composite emulsion, the mass percent of the fluorescent powder is 7 ~ 15%.

5. The method for preparing the water-based acrylic fluorescent paint according to claim 3, characterized in that: the emulsion A comprises the following components in parts by weight:

the amount of methyl methacrylate 2 ~ 4 was such that,

the amount of water 3 ~ 5 that is added to the water,

potassium persulfate 0.03 ~ 0.05.05,

sodium dodecyl sulfate 0.04 ~ 0.06.06;

the emulsion B comprises the following components in parts by weight:

methyl methacrylate 1.5 ~ 2,

n-butyl acrylate 2 ~ 4 as an active ingredient,

0.3 ~ 0.5.5 parts of methacrylic acid,

0.3 part of hydroxyethyl acrylate 0.3 ~ 0.5.5 part,

sodium dodecyl sulfate 0.04 ~ 0.06.06,

potassium persulfate 0.05 ~ 0.07.07,

water 4 ~ 5;

the emulsion C comprises the following components in parts by weight:

n-butyl acrylate 1.5 ~ 2,

methacryloyloxytrimethylsilane 1 ~ 2,

perfluoroalkyl methyl ethyl acrylate 6 ~ 10 (mole fraction),

sodium dodecyl sulfate 0.05 ~ 0.08.08,

0.05 ~ 0.2.2 parts of potassium persulfate,

water 10 ~ 12.

6. The method for preparing the aqueous acrylic fluorescent paint of claim 1 ~ 5, wherein the method comprises the steps of S2, adding the silica-coated modified phosphor into an aqueous solvent, stirring to obtain a modified phosphor suspension, adding a pH regulator and a dispersant, stirring, adding into an emulsion A containing methyl methacrylate, adding into an emulsion B and an emulsion C, adding into an initiator, reacting for 1h, adding a silane monomer, continuing to react for more than 2h, cooling, and adjusting the pH value to 6.5-7.5 to obtain stable nano SiO₂Acrylate composite emulsion; wherein the silane reactive monomer contains a carbon-carbon double bond.

7. The method for preparing the water-based acrylic fluorescent paint according to claim 6, characterized in that: the silane reaction monomer is one or a mixture of more than two of methacryloxypropyltriethoxysilane, vinyl trimethoxysilane and vinyl triethoxysilane.

8. The method for preparing the water-based acrylic fluorescent paint according to claim 6, characterized in that: the dispersing agent comprises at least one of sodium dodecyl sulfate, sodium alkyl benzene sulfonate, fatty acid sulfoalkyl amide and fatty alcohol sulfate; the pH regulator comprises at least one of sodium bicarbonate, potassium bicarbonate, sodium oxalate, potassium oxalate and ammonium oxalate.

9. The method for preparing the water-based acrylic fluorescent paint according to claim 6, characterized in that: in step S2, the modified phosphor suspension is added to the reaction system in two steps, a part of the phosphor suspension is added before the initiator is added, and the remaining modified phosphor suspension is added during the reaction when the silane reaction monomer is added.

10. The water-based acrylic fluorescent paint is characterized by being prepared by the preparation method of the water-based acrylic fluorescent paint according to any one of claim 1 ~ 9.

Technical Field

The invention belongs to the technical field of coatings, and particularly relates to a water-based acrylic fluorescent coating and a preparation method thereof.

Background

The current methods for preparing fluorescent paint include: (1) synthesizing resin with a fluorescent effect, and utilizing the fluorescent property of the resin to emit light; (2) and adding fluorescent powder as a filler to prepare the fluorescent paint. The first method has complex preparation process and strict requirements on process conditions, and uses a large amount of organic solvent, and the residual organic solvent can cause environmental pollution. The second method is relatively simple in process, but the dispersion of the fluorescent powder has problems, so that the luminescence is not uniform, and the local fluorescence is quenched.

In the currently published documents, there are some researches on fluorescent paint, for example, chinese patent CN201510614889.7, a method for preparing acrylic fluorescent paint, although it obtains fluorescent paint, the paint does not have low surface energy, antifouling and self-cleaning properties. The fluorescent paint disclosed in chinese patent CN201710283423.2, polyacrylate/polyurethane fluorescent paint and the preparation method thereof, has a luminescent substrate of fluorescent resin, the synthetic process is complicated, and a large amount of organic solvents are used in the synthetic process, which is not favorable for environmental protection. The nanometer antibacterial low-surface-energy organic silicon luminous antifouling paint disclosed in Chinese patent CN201410545977.1 and the preparation method thereof disclose that the fluorescent paint is a solvent type organic silicon paint, wherein the solvent is ketones, aromatic hydrocarbons and alcohols, which are not beneficial to environmental protection; and the fluorescence is energy storage afterglow fluorescence rather than excitation fluorescence, the contact angle disclosed by the patent is about 110 degrees on average, and the surface energy of the fluorescence needs to be further improved.

In the preparation process of the fluorescent paint, the fluorescent powder is coated by organic matters, but experiments show that the organic matter coating can cause the problem of agglomeration in the preparation process of the paint and is not beneficial to uniform dispersion, thereby causing low fluorescence luminous intensity and efficiency.

Disclosure of Invention

Aiming at the technical problems, the invention discloses a water-based acrylic fluorescent paint and a preparation method thereof, which can obtain the fluorescent paint with uniform luminescence and good luminous intensity, simplify the preparation process, reduce the pollution to the environment without using organic solvents, further endow the fluorescent paint with lower surface energy, enhance the antifouling and self-cleaning capability and prolong the service life.

In contrast, the technical scheme adopted by the invention is as follows:

a preparation method of a water-based acrylic fluorescent paint comprises the following steps:

step S1, preparing silicon dioxide coated modified fluorescent powder;

step S2, adding the obtained silicon dioxide coated modified fluorescent powder into an aqueous solvent, stirring to obtain a modified fluorescent powder suspension, adding the modified fluorescent powder suspension into an emulsion containing an acrylate monomer, adding an initiator for reaction, and adjusting the pH value to 6.5-7.5 to obtain stable nano SiO₂Acrylate composite emulsion;

wherein the components of the emulsion B comprise methyl methacrylate; the components of the emulsion C comprise n-butyl acrylate;

the nano SiO obtained in the step S2₂And uniformly mixing the acrylate composite emulsion with a curing agent and an auxiliary agent to obtain the water-based acrylic fluorescent paint.

By adopting the technical scheme, the inorganic substance is adopted to coat the fluorescent powder, the process is simpler, the performance achieved by coating is different from that achieved by coating of the organic substance, the silicon dioxide coated modified fluorescent powder has the function of enhancing the refractive index, stable luminescence is realized, and the fluorescent powder can be uniformly dispersed in water and can normally emit light.

Further, the components of the emulsion B comprise methyl methacrylate and n-butyl acrylate. Further, the components of the emulsion B also comprise methacrylic acid and hydroxyethyl acrylate.

Further, the components of the emulsion C comprise n-butyl acrylate, methacryloxy trimethyl silane and perfluoroalkyl methyl ethyl acrylate;

as a further improvement of the present invention, in step S1, a silica gel coated phosphor is prepared by a sol-gel method, and then calcined and cooled to obtain a silica coated modified phosphor.

As a further improvement of the invention, the silicon dioxide coated modified fluorescent powder is prepared by the following steps: dissolving ethyl orthosilicate in an ethanol solution, adjusting the pH value to 3-4, and heating and stirring at 40-60 ℃ to obtain transparent sol; then, soaking the fluorescent powder into the sol, stirring for 40-60 min at 50-100 ℃, adjusting the pH value to 6-7, and standing for completely gelling; and finally, drying the mixture in an oven at the temperature of 60-100 ℃, calcining the mixture for 2-4 hours at the temperature of 400-500 ℃, cooling and grinding the calcined mixture.

As a further improvement of the invention, the mass ratio of the ethyl orthosilicate to the fluorescent powder is 1: 1-3.

Further, the mass ratio of the ethyl orthosilicate to the fluorescent powder is 1: 2.

As a further improvement of the invention, the nano SiO₂In the acrylate composite emulsion, the mass percent of the fluorescent powder is 7-15%.

As a further improvement of the invention, the emulsion A comprises the following components in parts by weight:

as a further improvement of the invention, the emulsion B comprises the following components in parts by mass:

as a further improvement of the invention, the emulsion C comprises the following components in parts by mass:

by adopting the technical scheme, the reaction monomers comprise various acrylate monomers and fluorosilicone acrylate, so that the fluorescent paint obtained after the polymerization reaction in the step S2 takes the coated and modified fluorescent powder as a core, takes the acrylate copolymer as an inner shell and takes the fluorosilicone acrylate as an outer shell and has stable low surface energy.

As a further improvement of the invention, in step S2, adding the obtained silicon dioxide coated modified phosphor into an aqueous solvent, stirring to obtain a modified phosphor suspension, adding a pH regulator and a dispersant, stirring, then adding into an emulsion A containing methyl methacrylate, then adding into an emulsion B and an emulsion C, adding an initiator, adding a silane reaction monomer after reacting for 1h, continuing to react for more than 2h, cooling, and adjusting the pH value to 6.5-7.5 to obtain stable nano SiO₂Acrylate composite emulsion; wherein the silane reactive monomer contains a carbon-carbon double bond.

As a further improvement of the invention, the silane reaction monomer is one or a mixture of more than two of methacryloxypropyltriethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane.

As a further improvement of the present invention, the dispersant comprises at least one of sodium dodecyl sulfate, sodium alkyl benzene sulfonate, fatty acid sulfoalkyl amide, fatty alcohol sulfate; the pH regulator comprises at least one of sodium bicarbonate, potassium bicarbonate, sodium oxalate, potassium oxalate and ammonium oxalate.

As a further improvement of the present invention, in step S2, the modified phosphor suspension is added to the reaction system in two steps, a part of the phosphor suspension is added before the initiator is added, and the remaining modified phosphor suspension is added during the reaction when the silane reaction monomer is added.

As a further improvement of the invention, in step S3, the prepared nano SiO₂Adding 1-3% of defoaming agent, 3-5% of thickening agent, 1-6% of auxiliary agent and 15-30% of curing agent into the acrylate composite emulsion under the condition of dispersion, and stirring for 30min to obtain the low-surface-energy fluorescent paint.

Specifically, the preparation method of the water-based acrylic fluorescent paint comprises the following steps:

1. the silica is coated with the modified fluorescent powder.

Weighing one part of tetraethoxysilane, dissolving the tetraethoxysilane in 1.5 parts of ethanol and 3 parts of water, adjusting the pH value to 3-4 by using hydrochloric acid, heating and stirring for 20-30 min at 40-60 ℃ to form transparent sol, immersing 2 parts of fluorescent powder into the sol, stirring for 40-60 min at 50-100 ℃, adjusting the pH value to 6-7 by using ammonia water, standing for completely gelling, placing the sol in an oven at 60-100 ℃ for drying, calcining for 2-4 h at 400-500 ℃, cooling and grinding.

2. And preparing the water-based acrylic fluorescent emulsion.

Mixing 10 parts of anhydrous ethanol and 60 parts of water, adding 4-10 parts of modified fluorescent powder while stirring, and stirring for 30min for later use; adding 1/2 fluorescent powder suspension into a three-neck flask provided with a stirring, condensing and refluxing pipe and a thermometer, and adding 0.5-1 part of NaHCO₃And 0.4-0.5 part of sodium dodecyl sulfate, and mechanically stirring for 1 hour; heating to 75 ℃, adding the pre-emulsified emulsion A, reacting for half an hour, heating to 80 ℃, starting to continuously dropwise add the emulsion B and the emulsion C, and synchronously dropwise adding an initiator aqueous solution. After dropwise adding for 3-4 h, reacting at constant temperature for 1h, adding the rest phosphor powder suspension and 2-4 parts of Methacryloxypropyltriethoxysilane (MAPTIPS), reacting at constant temperature for 4h, cooling to below 40 ℃, adjusting the pH value to about 7 with ammonia water to obtain the stable nano SiO₂Acrylate composite emulsion.

The ingredients of the emulsion A, B, C are shown in Table 1 below:

TABLE 1 ingredient Table of emulsion A, B, C

3. And preparing the fluorescent paint.

And (2) placing the prepared emulsion into a paint mixing tank, dispersing at the rotating speed of 700-800 rad/min by using a high-speed dispersion machine, adding 1-3% of defoaming agent, 3-5% of thickening agent, 1-6% of auxiliary agent and 15-30% of curing agent while dispersing, and stirring for 30min to obtain the low-surface-energy fluorescent paint.

The invention also discloses a water-based acrylic fluorescent paint which is prepared by adopting the preparation method of the water-based acrylic fluorescent paint.

Compared with the prior art, the invention has the beneficial effects that:

firstly, the technical scheme of the invention adopts silicon dioxide to coat and modify the fluorescent powder, then uses the modified fluorescent powder as a core, and carries out reaction in aqueous dispersion at normal pressure and low temperature, so that the fluorescent powder is uniformly dispersed in emulsion, and harmful organic solvent is not suitable for use in the reaction process; the integrity of the physical and chemical properties of the core fluorescent powder can be kept, the stability of the solution can be improved, the process adjustment of the silicon dioxide coating material is convenient, the optical transparency is good, and the luminous performance of the fluorescent powder is not influenced at all. In addition, the film-forming property of the emulsion is changed through the proportion of the auxiliary agent, so that the fluorescent paint with uniform luminescence can be obtained, and the contact angle of the coating film of the fluorescent paint can reach 120 degrees, so that the fluorescent paint has lower surface energy and better antifouling property.

Secondly, the technical scheme of the invention introduces functional groups such as hydroxyl, alkoxy and the like and crosslinking points on the long chain of the resin due to the addition of hydroxyethyl acrylate and vinyl trimethoxy silane, thereby greatly improving the adhesive force of the coating.

Thirdly, the coating is water-based emulsion, and an organic solvent is not used in the preparation process, so that the coating is environment-friendly.

Detailed Description

Preferred embodiments of the present invention are described in further detail below.