Low-VOC (volatile organic compound) formula waterborne polyurethane industrial paint and preparation method thereof

Abstract

The invention discloses low-VOC (volatile organic compound) formula waterborne polyurethane industrial paint and a preparation method thereof, and relates to the field of paint. The waterborne polyurethane industrial paint with the low VOC formula is prepared from a waterborne polyurethane emulsion, fluoride-based nanoparticles, aliphatic isocyanate, a self-repairing polymer, carbon nanotubes, silane quaternary ammonium salt, a photosensitive curing agent, indium tin oxide, polydimethylsiloxane, zinc pyrithione, polyether siloxane and ammonium tripolyphosphate. According to the waterborne polyurethane industrial paint, the waterborne polyurethane emulsion, the self-repairing polymer, the carbon nanotubes, the indium tin oxide, the aliphatic isocyanate, the polyether siloxane and the like are combined, and the waterborne polyurethane industrial paint is low in VOC, excellent in wear resistance, weather resistance, static resistance and self-repairing performance, environmentally friendly, safe, wide in application prospect and suitable for popularization and application. And lasting protection and attractive effects can be provided for the industrial environment, and meanwhile the convenience of operation and maintenance is improved.

Description

Technical Field

[0001] The invention relates to the field of coatings, and in particular to a low-VOC formula water-based polyurethane industrial paint and a preparation method thereof. Background Art

[0002] Traditional solvent-based polyurethane coatings contain a large amount of organic solvents, which release a large amount of VOC during the coating and drying process, which has an adverse effect on the environment and human health. With the improvement of environmental protection requirements, low-VOC or even zero-VOC waterborne polyurethane coatings have become the focus of research. However, the performance of existing waterborne polyurethane coatings in terms of hardness, adhesion, weather resistance, etc. still needs to be improved, especially in the industrial field, where higher requirements are placed on the wear resistance and chemical resistance of the coating. Therefore, it is urgent to develop a low-VOC and excellent performance waterborne polyurethane industrial paint. Summary of the invention

[0003] In view of this, the present invention aims to provide a low-VOC formula water-based polyurethane industrial paint and a preparation method thereof. The coating replaces traditional organic solvents with a water-based system, significantly reduces the emission of volatile organic compounds, and ensures its durability and environmental protection without reducing the performance of the coating, reduces VOC emissions, and does not reduce the performance of the coating. It has excellent adhesion, wear resistance, weather resistance and corrosion resistance, while reducing the impact on the environment.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] In a first aspect, the present invention provides a low VOC waterborne polyurethane industrial paint, the low VOC waterborne polyurethane industrial paint comprising the following raw materials in parts by weight:

[0006] 75-125 parts of waterborne polyurethane emulsion; 1.5-3.5 parts of fluoride-based nanoparticles; 5-10 parts of aliphatic isocyanate; 2-6 parts of self-healing polymer; 0.5-1 parts of carbon nanotubes; 1-2 parts of silane quaternary ammonium salt; 3-5 parts of photosensitive curing agent; 2-8 parts of indium tin oxide; 0.3-0.8 parts of polydimethylsiloxane; 0.5-1.5 parts of zinc pyrithione; 1-3 parts of polyether siloxane, and 5-10 parts of ammonium tripolyphosphate.

[0007] As a further scheme of the present invention, the low VOC formula water-based polyurethane industrial paint includes the following raw materials in parts by weight: 100 parts of water-based polyurethane emulsion; 2.5 parts of fluoride-based nanoparticles; 7.5 parts of aliphatic isocyanate; 4 parts of self-healing polymer; 0.75 parts of carbon nanotubes; 1.5 parts of silane quaternary ammonium salt; 4 parts of photosensitive curing agent; 5 parts of indium tin oxide; 0.55 parts of polydimethylsiloxane; 1 part of zinc pyrithione; 2 parts of polyether siloxane, and 7.5 parts of ammonium tripolyphosphate.

[0008] As a further scheme of the present invention, the waterborne polyurethane emulsion is prepared from polyether polyol, diisocyanate, chain extender and neutralizer through an emulsification process. When preparing through the emulsification process, polyether polyol and diisocyanate are added to a reactor according to a ratio, stirred and reacted at 70-90° C. to form a prepolymer containing an isocyanate group; a chain extender is added to the prepolymer, and the reaction is continued to form a high molecular weight polyurethane; a neutralizer is added to the polyurethane solution after chain extension, and a neutralization reaction is carried out to form a polyurethane with a carboxylate group; the neutralized polyurethane solution is slowly added to ethyl acetate for emulsification, and the stirring speed and temperature are adjusted to form a stable waterborne polyurethane emulsion; and the ethyl acetate solvent is removed by reduced pressure distillation to obtain the final waterborne polyurethane emulsion.

[0009] As a further embodiment of the present invention, the diisocyanate is HDI (hexamethylene diisocyanate) or MDI (diphenylmethane diisocyanate), the chain extender is a diamine or a diol, and the neutralizer is triethylamine.

[0010] As a further solution of the present invention, the fluoride-based nanoparticles are super-hydrophobic nanoparticles, using PFOA (perfluorooctanoic acid) modified particles with a particle size ranging from 1 to 100 nanometers.

[0011] As a further scheme of the present invention, the aliphatic isocyanate is used for the polyurethane prepolymer reaction to form a cross-linked structure, and the aliphatic isocyanate is prepared by the prepolymerization reaction of diisocyanate and polyethylene glycol. The diisocyanate and polyethylene glycol are mixed in proportion in a reactor, stirred to form a prepolymer, and cooled to obtain an aliphatic isocyanate curing agent.

[0012] As a further solution of the present invention, the self-healing polymer is composed of a shell material and a core material, wherein the core material is emulsified into tiny droplets, and a polymerization reaction is carried out on the surface of the core material to form microcapsules coated with the shell material, and self-healing polymer microcapsules are obtained after washing and drying.

[0013] As a further solution of the present invention, the core material of the self-healing polymer is two-component polyurethane, and the shell material is polyurea.

[0014] As a further solution of the present invention, the carbon nanotubes are antistatic additives with a particle size of 10-50 nanometers and an oxidation treatment on the surface.

[0015] As a further solution of the present invention, the silane quaternary ammonium salt forms a chemical bond with the substrate through the silane group, and is prepared by adding the silane quaternary ammonium salt to the waterborne polyurethane prepolymer and uniformly dispersing it under stirring, wherein the stirring temperature is 40-50° C. and the stirring speed is 200-500 r / min. The prepared silane quaternary ammonium salt is used as an antibacterial agent, and the pH value is 6.0-7.5 (1% aqueous solution).

[0016] As a further embodiment of the present invention, the photosensitive curing agent is 2-hydroxy-4'-(2-hydroxyethoxy)benzophenone, and the curing light source is an ultraviolet lamp with an energy density of 100-200 mW / cm 2 , wavelength range is 320-400nm, curing temperature is 25-30℃, and curing time is 2-10 seconds.

[0017] As a further solution of the present invention, the indium tin oxide is an infrared reflective pigment with a particle size of 20-100 nanometers and an infrared reflection band ranging from 750-2500 nm.

[0018] As a further solution of the present invention, polydimethylsiloxane is used as a defoaming agent, the dynamic viscosity is 100-500 mPa.s, the addition temperature is 20-30°C, and the stirring speed is 100-300 rpm.

[0019] As a further embodiment of the present invention, the particle size of zinc pyrithione is ≤5 microns, the viscosity of polyether siloxane is 50-200 mPa.s, and the decomposition temperature of ammonium tripolyphosphate is greater than 200°C.

[0020] In a second aspect, the present invention also provides a method for preparing a waterborne polyurethane industrial paint based on a low VOC formula, the steps being as follows:

[0021] 1) weighing waterborne polyurethane emulsion, fluoride-based nanoparticles, aliphatic isocyanate, self-healing polymer, carbon nanotubes, silane quaternary ammonium salt, photosensitive curing agent, indium tin oxide, polydimethylsiloxane, zinc pyrithione, polyether siloxane and ammonium tripolyphosphate according to weight parts for standby use;

[0022] 2) Raw material pretreatment: the carbon nanotubes are mixed with deionized water and uniformly dispersed by an ultrasonic disperser at 25-30° C. for 20-30 minutes to prevent the carbon nanotubes from agglomerating and form a stable suspension; and the fluoride-based nanoparticles are dispersed in deionized water by a high-shear mixer at 25-30° C. for 10-15 minutes at high speed;

[0023] 3) Preparation of emulsion base: Adding waterborne polyurethane emulsion as base into a reaction kettle, and stirring at a stirring speed of 500-800 r / min, and controlling the stirring temperature at 25-35° C. to obtain polyurethane emulsion;

[0024] 4) slowly adding the weighed silane quaternary ammonium salt to the polyurethane emulsion under continuous stirring, and adding the weighed zinc pyrithione under stirring, stirring for 10-15 minutes to form a coating system, and adding the photosensitive curing agent and indium tin oxide to the coating system in the form of a uniformly dispersed slurry, using a high-speed stirrer to disperse at a speed of 800-1200 r / min, maintaining the stirring time for 15-20 minutes, and controlling the temperature at 30-40° C.;

[0025] 5) adding a polyether siloxane leveling agent to the coating system of step 4), controlling the stirring speed at 300-600 r / min, slowly adding a polydimethylsiloxane defoamer under stirring, controlling the temperature at 25-30° C., and stirring for 5-10 minutes to obtain an emulsion system;

[0026] 6) Add the self-healing polymer to the emulsion system and stir at 100-300 r / min. After stirring for 10-20 minutes, slowly add ammonium tripolyphosphate for dispersion, maintain the temperature at 30-35°C, and stir for 15-30 minutes; and gradually add aliphatic isocyanate to the emulsion system and stir to increase the crosslinking density. After all the raw materials are added, continue stirring for 30 minutes, let stand at room temperature for 1-2 hours for degassing, and obtain the prepared waterborne polyurethane industrial paint.

[0027] As a further embodiment of the present invention, the prepared waterborne polyurethane industrial paint is applied by brushing or roller coating evenly on the surface of the substrate to be coated, and the coating is photocured under ultraviolet light. After curing, the coating is dried at 40-60°C or left to stand at room temperature for 24 hours to completely dry, wherein the curing conditions are: ultraviolet light, energy density of 100-200mW / cm 2 , wavelength range is 320-400nm, curing temperature is 25-30℃, and curing time is 2-10 seconds.

[0028] Compared with the prior art, the low-VOC waterborne polyurethane industrial paint and the preparation method thereof of the present invention have the following beneficial effects:

[0029] 1. Environmental protection and low VOC emissions are achieved through water-based systems and low-toxicity formulas. The present invention uses water as the main dispersion medium, reduces the use of organic solvents, greatly reduces the emission of volatile organic compounds (VOCs), complies with environmental regulations and standards, and is suitable for indoor and industrial environments. By using water-based polyurethane emulsions and safe functional additives, the safety and low toxicity of the entire coating system are ensured, which is beneficial to the health of operators and reduces environmental pollution.

[0030] 2. Excellent wear resistance and weather resistance are achieved through the cross-linking enhancement of aliphatic isocyanate and the addition of self-healing polymer. The present invention increases the cross-linking density of the coating by adding aliphatic isocyanate, so that the coating has higher hardness and elasticity after curing, thereby significantly improving the wear resistance and impact resistance of the coating. The self-healing polymer added to the coating gives the coating the ability to self-repair after slight damage, effectively extending the service life of the coating.

[0031] 3. Possessing multifunctional protective properties of antibacterial, anticorrosive and antistatic properties. The zinc pyrithione added to the coating of the present invention acts as an antibacterial agent and preservative, which can effectively prevent the growth of microorganisms and ensure that the coating can maintain its integrity and functionality for a long time in a humid or harsh environment. The addition of indium tin oxide (ITO) makes the coating conductive, thereby providing an antistatic effect, and is suitable for use in industrial occasions where antistatic is required, such as electronic production workshops and chemical storage areas.

[0032] 4. It has excellent infrared reflectivity and thermal management effects. The addition of indium tin oxide (ITO) nanoparticles in the present invention not only improves the antistatic performance, but also has infrared reflection ability. This function helps to reduce heat accumulation on the surface of industrial equipment and buildings, thereby achieving energy saving and cooling effects. The low surface energy characteristics of fluoride-based nanoparticles not only improve the hydrophobicity of the coating, but also enhance the reflection of ultraviolet and infrared rays, which helps to extend the life of the coating and improve its anti-aging ability.

[0033] 5. Excellent leveling and coating uniformity. The use of polyether siloxane leveling agent in the present invention significantly improves the leveling of the coating and the smoothness of the coating surface, ensuring a uniform and traceless surface effect during the coating process, thereby improving the aesthetics and adhesion of the coating. The addition of polydimethylsiloxane defoamer effectively prevents the generation of bubbles and improves the smoothness and surface quality of the coating.

[0034] 6. It also has high flame retardancy and fast light curing properties. The ammonium tripolyphosphate contained in the coating of the present invention is used as a flame retardant, which can effectively reduce the burning speed when a fire occurs, improve the flame retardancy level of the coating, and ensure the safety of equipment and the environment. It is particularly suitable for industrial environments with high fire protection requirements. The Irgacure 2959 photosensitive curing agent used can quickly initiate polymerization under ultraviolet light irradiation to achieve rapid curing. This feature not only improves construction efficiency, but also makes the coating fully functional in a short time, which is suitable for industrial rapid production and large-area coating.

[0035] 7. Enhanced coating adhesion and corrosion resistance, with excellent surface hydrophobicity and antifouling effect. The addition of silane quaternary ammonium salt in the present invention can form a chemical bond between the coating and the substrate, effectively improve the adhesion of the coating, and ensure that the coating will not peel off or bubble during long-term use. The added nano-scale carbon nanotubes enhance the mechanical properties of the coating and improve the chemical corrosion resistance, especially in an acid-base environment, the coating can still maintain its integrity and protective effect. The coating is also given excellent hydrophobic and antifouling properties by fluoride-based nanoparticles, and the coating surface has a self-cleaning effect, which effectively prevents the adhesion of stains and dust, and reduces maintenance costs and cleaning frequency.

[0036] 8. Wide range of applications. Due to the low VOC, excellent wear resistance, weather resistance, antistatic and self-healing properties of the present invention, the coating of the present invention is suitable for a variety of industrial scenarios, including electronic manufacturing, building coatings, industrial equipment coatings, anti-corrosion facilities and other fields requiring multifunctional protection.

[0037] In summary, the low-VOC waterborne polyurethane industrial paint of the present invention is not only environmentally friendly and safe, but also has broad application prospects. It can provide lasting protection and aesthetic effects for industrial environments, while improving the convenience of operation and maintenance.

[0038] In order to more clearly illustrate the structural features and effects of the present invention, the present invention is described in detail below in conjunction with specific embodiments. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.

[0040] Example 1

[0041] The present embodiment provides a low VOC waterborne polyurethane industrial paint, comprising the following raw materials in parts by weight:

[0042] 75 parts of waterborne polyurethane emulsion; 1.5 parts of fluoride-based nanoparticles; 5 parts of aliphatic isocyanate; 2 parts of self-healing polymer; 0.5 parts of carbon nanotubes; 1 part of silane quaternary ammonium salt; 3 parts of photosensitive curing agent; 2 parts of indium tin oxide; 0.3 parts of polydimethylsiloxane; 0.5 parts of zinc pyrithione; 1 part of polyether siloxane, and 5 parts of ammonium tripolyphosphate.

[0043] In this embodiment, the aqueous polyurethane emulsion is prepared from polyether polyol, diisocyanate, chain extender and neutralizer by an emulsification process. When preparing by the emulsification process, polyether polyol and diisocyanate are added to a reactor according to a ratio, stirred and reacted at 80° C. to form a prepolymer containing an isocyanate group; a chain extender is added to the prepolymer, and the reaction is continued to form a high molecular weight polyurethane, and a neutralizer is added to the polyurethane solution after chain extension to perform a neutralization reaction to form a polyurethane with a carboxylate group; the neutralized polyurethane solution is slowly added to ethyl acetate for emulsification, and the stirring speed and temperature are adjusted to form a stable aqueous polyurethane emulsion; the ethyl acetate solvent is removed by reduced pressure distillation to obtain a final aqueous polyurethane emulsion, wherein the diisocyanate is MDI, the chain extender is a diamine or a diol, and the neutralizer is triethylamine.

[0044] In this embodiment, the fluoride-based nanoparticles are PFOA-modified particles with a particle size range of 1 to 100 nanometers, the carbon nanotubes are antistatic additives with a particle size of 10 to 50 nanometers and a surface oxidation treatment, and the photosensitive curing agent is 2-hydroxy-4'-(2-hydroxyethoxy) benzophenone.

[0045] The preparation method of the low VOC waterborne polyurethane industrial paint in this embodiment comprises the following steps:

[0046] 1) weighing waterborne polyurethane emulsion, fluoride-based nanoparticles, aliphatic isocyanate, self-healing polymer, carbon nanotubes, silane quaternary ammonium salt, photosensitive curing agent, indium tin oxide, polydimethylsiloxane, zinc pyrithione, polyether siloxane and ammonium tripolyphosphate according to weight parts for standby use;

[0047] 2) Raw material pretreatment: the carbon nanotubes were mixed with deionized water and uniformly dispersed by an ultrasonic disperser at 25° C. for 30 minutes to prevent the carbon nanotubes from agglomerating and forming a stable suspension; and the fluoride-based nanoparticles were dispersed in deionized water by high-speed stirring at 25° C. for 15 minutes by a high shear mixer;

[0048] 3) Preparation of emulsion base: adding waterborne polyurethane emulsion as a base into a reaction kettle, and starting stirring at a stirring speed of 500 r / min, and controlling the stirring temperature at 25° C. to obtain a polyurethane emulsion;

[0049] 4) slowly adding the weighed silane quaternary ammonium salt to the polyurethane emulsion under continuous stirring, and adding the weighed zinc pyrithione under stirring, stirring for 15 minutes to form a coating system, and adding the photosensitive curing agent and indium tin oxide to the coating system in the form of a uniformly dispersed slurry, using a high-speed stirrer to disperse at a speed of 800 r / min, maintaining the stirring time for 20 minutes, and controlling the temperature at 30° C.;

[0050] 5) adding a polyether siloxane leveling agent to the coating system of step 4), controlling the stirring speed at 300 r / min, slowly adding a polydimethylsiloxane defoamer under stirring, controlling the temperature at 25° C., and stirring for 5 minutes to obtain an emulsion system;

[0051] 6) Add the self-healing polymer to the emulsion system and stir at 300 r / min. After stirring for 10 minutes, slowly add ammonium tripolyphosphate for dispersion. Keep the temperature at 30°C and stir for 30 minutes. Gradually add aliphatic isocyanate to the emulsion system and stir to increase the crosslinking density. After all the raw materials are added, continue stirring for 30 minutes, let stand at room temperature for 2 hours for degassing, and obtain the prepared waterborne polyurethane industrial paint.

[0052] Example 2

[0053] The present embodiment provides a low VOC waterborne polyurethane industrial paint, comprising the following raw materials in parts by weight:

[0054] 85 parts of waterborne polyurethane emulsion; 2 parts of fluoride-based nanoparticles; 7 parts of aliphatic isocyanate; 3 parts of self-healing polymer; 1.6 parts of carbon nanotubes; 1.5 parts of silane quaternary ammonium salt; 4 parts of photosensitive curing agent; 5 parts of indium tin oxide; 0.5 parts of polydimethylsiloxane; 1 part of zinc pyrithione; 1.5 parts of polyether siloxane and 6 parts of ammonium tripolyphosphate.

[0055] The difference from Example 1 is that the aqueous polyurethane emulsion is prepared from polyether polyol, diisocyanate, chain extender and neutralizer by an emulsification process. When preparing by the emulsification process, polyether polyol and diisocyanate are added to a reactor according to a ratio, stirred and reacted at 85° C. to form a prepolymer containing an isocyanate group; a chain extender is added to the prepolymer, and the reaction is continued to form a high molecular weight polyurethane; a neutralizer is added to the polyurethane solution after chain extension, and a neutralization reaction is performed to form a polyurethane with a carboxylate group; the neutralized polyurethane solution is slowly added to ethyl acetate for emulsification, and the stirring speed and temperature are adjusted to form a stable aqueous polyurethane emulsion; the ethyl acetate solvent is removed by reduced pressure distillation to obtain a final aqueous polyurethane emulsion, wherein the diisocyanate is MDI, the chain extender is a diamine or a diol, and the neutralizer is triethylamine.

[0056] The preparation method of the low VOC waterborne polyurethane industrial paint in this embodiment comprises the following steps:

[0057] 1) weighing waterborne polyurethane emulsion, fluoride-based nanoparticles, aliphatic isocyanate, self-healing polymer, carbon nanotubes, silane quaternary ammonium salt, photosensitive curing agent, indium tin oxide, polydimethylsiloxane, zinc pyrithione, polyether siloxane and ammonium tripolyphosphate according to weight parts for standby use;

[0058] 2) Raw material pretreatment: the carbon nanotubes were mixed with deionized water and uniformly dispersed by an ultrasonic disperser at 30° C. for 20 minutes to prevent the carbon nanotubes from agglomerating and forming a stable suspension; and the fluoride-based nanoparticles were dispersed in deionized water by high-speed stirring at 30° C. for 15 minutes by a high shear mixer;

[0059] 3) Preparation of emulsion base: adding waterborne polyurethane emulsion as a base into a reaction kettle, and starting stirring at a stirring speed of 600 r / min, and controlling the stirring temperature at 30° C. to obtain a polyurethane emulsion;

[0060] 4) slowly adding the weighed silane quaternary ammonium salt to the polyurethane emulsion under continuous stirring, and adding the weighed zinc pyrithione under stirring, stirring for 15 minutes to form a coating system, and adding the photosensitive curing agent and indium tin oxide to the coating system in the form of a uniformly dispersed slurry, using a high-speed stirrer to disperse at a speed of 1000 r / min, maintaining the stirring time for 15 minutes, and controlling the temperature at 30° C.;

[0061] 5) adding a polyether siloxane leveling agent to the coating system of step 4), controlling the stirring speed at 400 r / min, slowly adding a polydimethylsiloxane defoamer under stirring, controlling the temperature at 30° C., and stirring for 10 minutes to obtain an emulsion system;

[0062] 6) Add the self-healing polymer to the emulsion system and stir at 200 r / min. After stirring for 20 minutes, slowly add ammonium tripolyphosphate for dispersion, maintain the temperature at 30°C, and stir for 30 minutes; and gradually add aliphatic isocyanate to the emulsion system to increase the crosslinking density. After all the raw materials are added, continue stirring for 30 minutes, let stand at room temperature for 2 hours for degassing, and obtain the prepared waterborne polyurethane industrial paint.

[0063] Example 3

[0064] The present embodiment provides a low VOC waterborne polyurethane industrial paint, comprising the following raw materials in parts by weight:

[0065] 100 parts of waterborne polyurethane emulsion; 2.5 parts of fluoride-based nanoparticles; 7.5 parts of aliphatic isocyanate; 4 parts of self-healing polymer; 0.75 parts of carbon nanotubes; 1.5 parts of silane quaternary ammonium salt; 4 parts of photosensitive curing agent; 5 parts of indium tin oxide; 0.55 parts of polydimethylsiloxane; 1 part of zinc pyrithione; 2 parts of polyether siloxane and 7.5 parts of ammonium tripolyphosphate.

[0066] The preparation method of the low VOC waterborne polyurethane industrial paint in this embodiment comprises the following steps:

[0067] 1) weighing waterborne polyurethane emulsion, fluoride-based nanoparticles, aliphatic isocyanate, self-healing polymer, carbon nanotubes, silane quaternary ammonium salt, photosensitive curing agent, indium tin oxide, polydimethylsiloxane, zinc pyrithione, polyether siloxane and ammonium tripolyphosphate according to weight parts for standby use;

[0068] 2) Raw material pretreatment: the carbon nanotubes were mixed with deionized water and uniformly dispersed by an ultrasonic disperser at 30° C. for 30 minutes to prevent the carbon nanotubes from agglomerating and forming a stable suspension; and the fluoride-based nanoparticles were dispersed in deionized water by a high-shear mixer at 30° C. for 10 minutes at high speed;

[0069] 3) Preparation of emulsion base: adding waterborne polyurethane emulsion as a base into a reaction kettle, and starting stirring at a stirring speed of 800 r / min, and controlling the stirring temperature at 30° C. to obtain a polyurethane emulsion;

[0070] 4) slowly adding the weighed silane quaternary ammonium salt to the polyurethane emulsion under continuous stirring, and adding the weighed zinc pyrithione under stirring, stirring for 15 minutes to form a coating system, and adding the photosensitive curing agent and indium tin oxide to the coating system in the form of a uniformly dispersed slurry, using a high-speed stirrer to disperse at a speed of 1200 r / min, maintaining the stirring time for 15 minutes, and controlling the temperature at 30° C.;

[0071] 5) adding a polyether siloxane leveling agent to the coating system of step 4), controlling the stirring speed at 500 r / min, slowly adding a polydimethylsiloxane defoamer under stirring, controlling the temperature at 30° C., and stirring for 10 minutes to obtain an emulsion system;

[0072] 6) Add the self-healing polymer to the emulsion system and stir at 300 r / min. After stirring for 10 minutes, slowly add ammonium tripolyphosphate for dispersion. Keep the temperature at 30°C and stir for 15 minutes. Gradually add aliphatic isocyanate to the emulsion system and stir to increase the crosslinking density. After all the raw materials are added, continue stirring for 30 minutes, let stand at room temperature for 1 hour for degassing, and obtain the prepared waterborne polyurethane industrial paint.

[0073] Example 4

[0074] The present embodiment provides a low VOC waterborne polyurethane industrial paint, comprising the following raw materials in parts by weight:

[0075] 100 parts of waterborne polyurethane emulsion; 3 parts of fluoride-based nanoparticles; 8 parts of aliphatic isocyanate; 5 parts of self-healing polymer; 0.8 parts of carbon nanotubes; 1.6 parts of silane quaternary ammonium salt; 4.5 parts of photosensitive curing agent; 6 parts of indium tin oxide; 0.7 parts of polydimethylsiloxane; 1.2 parts of zinc pyrithione; 2.5 parts of polyether siloxane and 9 parts of ammonium tripolyphosphate.

[0076] The preparation method of the low VOC waterborne polyurethane industrial paint in this embodiment comprises the following steps:

[0077] 1) weighing waterborne polyurethane emulsion, fluoride-based nanoparticles, aliphatic isocyanate, self-healing polymer, carbon nanotubes, silane quaternary ammonium salt, photosensitive curing agent, indium tin oxide, polydimethylsiloxane, zinc pyrithione, polyether siloxane and ammonium tripolyphosphate according to weight parts for standby use;

[0078] 2) Raw material pretreatment: the carbon nanotubes were mixed with deionized water and uniformly dispersed by an ultrasonic disperser at 28° C. for 25 minutes to prevent the carbon nanotubes from agglomerating and forming a stable suspension; and the fluoride-based nanoparticles were dispersed in deionized water by high-speed stirring at 28° C. for 13 minutes by a high shear mixer;

[0079] 3) Preparation of emulsion base: adding waterborne polyurethane emulsion as a base into a reaction kettle, and starting stirring at a stirring speed of 700 r / min, and controlling the stirring temperature at 28° C. to obtain a polyurethane emulsion;

[0080] 4) slowly adding the weighed silane quaternary ammonium salt to the polyurethane emulsion under continuous stirring, and adding the weighed zinc pyrithione under stirring, stirring for 12 minutes to form a coating system, and adding the photosensitive curing agent and indium tin oxide to the coating system in the form of a uniformly dispersed slurry, using a high-speed stirrer to disperse at a speed of 1000 r / min, maintaining the stirring time for 18 minutes, and controlling the temperature at 35° C.;

[0081] 5) adding a polyether siloxane leveling agent to the coating system of step 4), controlling the stirring speed at 500 r / min, slowly adding a polydimethylsiloxane defoamer under stirring, controlling the temperature at 28° C., and stirring for 8 minutes to obtain an emulsion system;

[0082] 6) Add the self-healing polymer to the emulsion system and stir at 250 r / min. After stirring for 15 minutes, slowly add ammonium tripolyphosphate for dispersion. Keep the temperature at 35°C and stir for 20 minutes. Gradually add aliphatic isocyanate to the emulsion system to increase the crosslinking density. After all the raw materials are added, continue stirring for 30 minutes and let stand at room temperature for 1.5 hours for degassing to obtain the prepared waterborne polyurethane industrial paint.

[0083] Example 5

[0084] The present embodiment provides a low VOC waterborne polyurethane industrial paint, comprising the following raw materials in parts by weight:

[0085] 125 parts of waterborne polyurethane emulsion; 3.5 parts of fluoride-based nanoparticles; 10 parts of aliphatic isocyanate; 6 parts of self-healing polymer; 1 part of carbon nanotubes; 2 parts of silane quaternary ammonium salt; 5 parts of photosensitive curing agent; 8 parts of indium tin oxide; 0.8 parts of polydimethylsiloxane; 1.5 parts of zinc pyrithione; 3 parts of polyether siloxane, and 10 parts of ammonium tripolyphosphate.

[0086] The preparation method of the low VOC waterborne polyurethane industrial paint in this embodiment comprises the following steps:

[0087] 1) weighing waterborne polyurethane emulsion, fluoride-based nanoparticles, aliphatic isocyanate, self-healing polymer, carbon nanotubes, silane quaternary ammonium salt, photosensitive curing agent, indium tin oxide, polydimethylsiloxane, zinc pyrithione, polyether siloxane and ammonium tripolyphosphate according to weight parts for standby use;

[0088] 2) Raw material pretreatment: the carbon nanotubes were mixed with deionized water and uniformly dispersed by an ultrasonic disperser at 25° C. for 30 minutes to prevent the carbon nanotubes from agglomerating and forming a stable suspension; and the fluoride-based nanoparticles were dispersed in deionized water by high-speed stirring at 25° C. for 15 minutes by a high shear mixer;

[0089] 3) Preparation of emulsion base: adding waterborne polyurethane emulsion as a base into a reaction kettle, and starting stirring at a stirring speed of 800 r / min, and controlling the stirring temperature at 25° C. to obtain a polyurethane emulsion;

[0090] 4) slowly adding the weighed silane quaternary ammonium salt to the polyurethane emulsion under continuous stirring, and adding the weighed zinc pyrithione under stirring, stirring for 15 minutes to form a coating system, and adding the photosensitive curing agent and indium tin oxide to the coating system in the form of a uniformly dispersed slurry, using a high-speed stirrer to disperse at a speed of 1200 r / min, maintaining the stirring time for 15 minutes, and controlling the temperature at 40° C.;

[0091] 5) adding a polyether siloxane leveling agent to the coating system of step 4), controlling the stirring speed at 600 r / min, slowly adding a polydimethylsiloxane defoamer under stirring, controlling the temperature at 25° C., and stirring for 10 minutes to obtain an emulsion system;

[0092] 6) Add the self-healing polymer to the emulsion system and stir at 300 r / min. After stirring for 20 minutes, slowly add ammonium tripolyphosphate for dispersion. Keep the temperature at 35°C and stir for 30 minutes. Gradually add aliphatic isocyanate to the emulsion system and stir to increase the crosslinking density. After all the raw materials are added, continue stirring for 30 minutes, let stand at room temperature for 2 hours for degassing, and obtain the prepared waterborne polyurethane industrial paint.

[0093] Comparative Example 1

[0094] An industrial paint comprises the following raw materials in parts by weight:

[0095] 100 parts of waterborne polyurethane emulsion; 7.5 parts of aliphatic isocyanate; 4 parts of self-healing polymer; 0.75 parts of carbon nanotubes; 1.5 parts of silane quaternary ammonium salt; 4 parts of photosensitive curing agent; 5 parts of indium tin oxide; 0.55 parts of polydimethylsiloxane; 1 part of zinc pyrithione; 2 parts of polyether siloxane, 7.5 parts of ammonium tripolyphosphate. Among them, the industrial paint does not contain fluoride-based nanoparticles.

[0096] Comparative Example 2

[0097] An industrial paint comprises the following raw materials in parts by weight:

[0098] 100 parts of waterborne polyurethane emulsion; 2.5 parts of fluoride-based nanoparticles; 7.5 parts of aliphatic isocyanate; 0.75 parts of carbon nanotubes; 1.5 parts of silane quaternary ammonium salt; 4 parts of photosensitive curing agent; 5 parts of indium tin oxide; 0.55 parts of polydimethylsiloxane; 1 part of zinc pyrithione; 2 parts of polyether siloxane, 7.5 parts of ammonium tripolyphosphate. Among them, the industrial paint does not contain a self-healing polymer.

[0099] Comparative Example 3

[0100] An industrial paint comprises the following raw materials in parts by weight:

[0101] 100 parts of waterborne polyurethane emulsion; 7.5 parts of aliphatic isocyanate; 0.75 parts of carbon nanotubes; 1.5 parts of silane quaternary ammonium salt; 4 parts of photosensitive curing agent; 5 parts of indium tin oxide; 0.55 parts of polydimethylsiloxane; 1 part of zinc pyrithione; 2 parts of polyether siloxane, 7.5 parts of ammonium tripolyphosphate. Among them, the industrial paint does not contain fluoride-based nanoparticles and self-healing polymers, and the preparation processes of comparative examples 1-3 are the same as those of example 3.

[0102] Effect verification:

[0103] The low VOC waterborne polyurethane industrial paints prepared in Examples 1-5 and the industrial paints prepared in Comparative Examples 1-3 were subjected to the following tests:

[0104] (1) VOC content test

[0105] Test item: VOC content.

[0106] Test method: gas chromatography, reference standard: GB / T 23986.

[0107] Test procedure: Take 0.5 g of the industrial paint prepared in Examples 1-5 and Comparative Examples 1-3 and place them in a sealed container; heat the sample in a constant temperature box at 60° C. for 2 hours to ensure that the organic volatiles are completely evaporated, use a gas chromatograph to detect the volatilized organic matter, and calculate the VOC content in the paint, wherein the test results are expressed in mg / L. The test results are shown in Table 1.

[0108] (2) Coating hardness test

[0109] Test item: coating hardness.

[0110] Test method: pencil hardness test, reference standard: GB / T 6739.

[0111] Test steps: The industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 were uniformly coated on the test plate and cured under standard curing conditions; pencils of different hardness (from 6B to 6H) were selected and pressed on the coating surface at a fixed angle of 45°, and the pencils were replaced in sequence until no obvious scratches appeared on the coating surface, and the hardness grade of the hardest pencil was recorded. The test results are shown in Table 1.

[0112] (3) Wear resistance test

[0113] Test item: abrasion resistance.

[0114] Test method: Taber abrasion test, reference standard: ASTM D4060.

[0115] Test steps: The industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 were uniformly coated on a metal or plastic plate and cured for a prescribed time; a Taber wear tester was used, a CS-10 wear wheel was selected, a pressure of 1000 g was applied, and 1000 friction cycles were performed on the sample; the sample mass before and after the test was recorded, and the wear mass difference was calculated in mg / 1000 friction cycles. The test results are shown in Table 1.

[0116] (4) Adhesion test

[0117] Test item: Adhesion.

[0118] Test method: cross-cut test, reference standard: GB / T 9286.

[0119] Test steps: The industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 are evenly coated on a metal or plastic plate and cured according to the standard; a cross grid with a certain spacing (8 cm) is drawn on the coating using a cross-grid knife to ensure that the cross-grid is drawn through to the substrate; a special tape is used to cover the cross-grid area, and then the tape is peeled off with a uniform force to observe the shedding of the coating in the grid; the adhesion level is evaluated according to the shedding situation, with level 1 indicating the best adhesion and level 5 indicating the worst. The test results are shown in Table 1.

[0120] (5) Corrosion resistance test

[0121] Test item: corrosion resistance.

[0122] Test method: Salt spray test, reference standard: ASTM B117.

[0123] Test steps: The industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 were uniformly coated on a metal plate and treated under standard curing conditions; the samples were placed in a salt spray chamber, a 5% sodium chloride solution was used, the ambient temperature was controlled at 35°C, and a continuous salt spray corrosion test was performed; a 500-hour test was performed as required, during which the corrosion of the coating was checked every 24 hours; the corrosion resistance was evaluated based on the blistering, peeling and corrosion degree of the coating, and the test results are shown in Table 1.

[0124] (6) Antibacterial performance test

[0125] Test item: Bacteria reduction rate.

[0126] Test method: colony counting method, reference standard: JISZ 2801.

[0127] Test steps: The industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 were uniformly coated on a glass plate and cured; Staphylococcus aureus was inoculated on the surface of the cured coating; the sample was placed in a constant temperature box for 24 hours, and then the surface of the sample was rinsed with sterile water, the rinse liquid was collected and the bacterial culture count was performed; the reduction rate of bacteria on the coating surface was calculated, and the CFU / cm 2 The antimicrobial effect is reported in units, and the test results are shown in Table 1.

[0128] (7) Infrared reflectivity test

[0129] Test item: infrared reflectivity.

[0130] Test method: infrared spectrophotometer test, reference standard: ASTM E903.

[0131] Test steps: The industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 were uniformly coated on a reflective plate and cured according to the standard; an infrared spectrophotometer was used to measure the reflectivity of the samples at wavelengths of 800nm, 1500nm and 2500nm; based on the reflection spectrum curve, the average infrared reflectivity of the samples was calculated and expressed as a percentage (%). The test results are shown in Table 1.

[0132] (8) Hydrophobicity test

[0133] Test item: hydrophobicity.

[0134] Test method: contact angle test, reference standard: GB / T 30693.

[0135] Test steps: The industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 were uniformly coated on a glass plate and cured according to the standard; a contact angle meter was used to drop a drop of deionized water on the coating surface to measure the contact angle of the water drop on the coating. A contact angle greater than 90° indicated that the surface was hydrophobic, and the larger the angle, the better the hydrophobicity. The test results are shown in Table 1.

[0136] (9) Flame retardant performance test

[0137] Test item: Flame retardant grade.

[0138] Test method: vertical burning test, reference standard: UL 94.

[0139] Test steps: The industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 were uniformly coated on a glass fiber board and cured according to the standard; in a fume hood, the bottom of the sample was ignited with a burner for 10 seconds, and then the flame extinguishing time and the residual length after burning were observed; the flame retardant grade was evaluated according to the burning time and residual length of the sample, V-0 being the best flame retardant performance and V-2 being the lowest flame retardant performance. The test results are shown in Table 1.

[0140] Test data:

[0141] Table 1 Test data summary

[0142]

[0143] Test results: The VOC content of the industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 is lower than 10 mg / L, which meets environmental protection requirements; the hardness of the industrial paint coatings prepared in Examples 1-5 is generally between 5H-7H, and the wear resistance is good, while the hardness and wear resistance of the comparative example are significantly lower; the adhesion of the industrial paint coatings prepared in Examples 1-5 reaches Level 1, and the corrosion resistance is also better than that of the comparative example coating; the antibacterial effect of the industrial paint coatings prepared in Examples 1-5 is significantly better than that of the comparative example coating, and the number of colonies is significantly reduced; the infrared reflectivity of the industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 is high, and has a good thermal management effect; the contact angles of the industrial paint coatings prepared in Examples 1-5 are all between 115°-122°, showing good hydrophobicity relative to the comparative example; the industrial paint coatings prepared in Examples 1-5 and Comparative Examples 1-3 all achieve V-0 flame retardant effect. The above test results show that the low-VOC water-based polyurethane industrial paint prepared in Examples 1-5 has significant effects in environmental protection, physical properties and functionality.

[0144] The low-VOC waterborne polyurethane industrial paint of the present invention is not only environmentally friendly and safe, but also has broad application prospects, can provide lasting protection and aesthetic effects for industrial environments, and at the same time improves the convenience of operation and maintenance.

[0145] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A low VOC waterborne polyurethane industrial paint, characterized in that: The invention comprises the following raw materials in parts by weight: 75-125 parts of waterborne polyurethane emulsion; 1.5-3.5 parts of fluoride-based nanoparticles; 5-10 parts of aliphatic isocyanate; 2-6 parts of self-healing polymer; 0.5-1 parts of carbon nanotubes; 1-2 parts of silane quaternary ammonium salt; 3-5 parts of photosensitive curing agent; 2-8 parts of indium tin oxide; 0.3-0.8 parts of polydimethylsiloxane; 0.5-1.5 parts of zinc pyrithione; 1-3 parts of polyether siloxane, and 5-10 parts of ammonium tripolyphosphate.

2. The low VOC waterborne polyurethane industrial paint according to claim 1, characterized in that: The low-VOC formula water-based polyurethane industrial paint includes the following raw materials in parts by weight: 100 parts of water-based polyurethane emulsion; 2.5 parts of fluoride-based nanoparticles; 7.5 parts of aliphatic isocyanate; 4 parts of self-healing polymer; 0.75 parts of carbon nanotubes; 1.5 parts of silane quaternary ammonium salt; 4 parts of photosensitive curing agent; 5 parts of indium tin oxide; 0.55 parts of polydimethylsiloxane; 1 part of zinc pyrithione; 2 parts of polyether siloxane and 7.5 parts of ammonium tripolyphosphate.

3. The low VOC waterborne polyurethane industrial paint according to claim 2, characterized in that: The waterborne polyurethane emulsion is prepared from polyether polyol, diisocyanate, chain extender and neutralizer through an emulsification process. When the waterborne polyurethane emulsion is prepared through the emulsification process, the polyether polyol and diisocyanate are added into a reactor according to a proportion, stirred and reacted at 70-90° C. to form a prepolymer containing an isocyanate group; the chain extender is added into the prepolymer, the reaction is continued to form a high molecular weight polyurethane, the neutralizer is added into the polyurethane solution after the chain extension, a neutralization reaction is carried out to form a polyurethane with a carboxylate group; the neutralized polyurethane solution is slowly added into ethyl acetate for emulsification, the stirring speed and temperature are adjusted to form a stable waterborne polyurethane emulsion; the ethyl acetate solvent is removed through reduced pressure distillation to obtain the final waterborne polyurethane emulsion.

4. The low VOC waterborne polyurethane industrial paint according to claim 3, characterized in that: The fluoride-based nanoparticles are super-hydrophobic nanoparticles, using PFOA-modified particles with a particle size ranging from 1 to 100 nanometers.

5. The low VOC waterborne polyurethane industrial paint according to claim 4, characterized in that: The aliphatic isocyanate is used for the polyurethane prepolymer reaction to form a cross-linked structure. The aliphatic isocyanate is prepared by the prepolymerization reaction of diisocyanate and polyethylene glycol. The diisocyanate and polyethylene glycol are mixed in a reactor in proportion, stirred to form a prepolymer, and cooled to obtain an aliphatic isocyanate curing agent.

6. The low VOC waterborne polyurethane industrial paint according to claim 5, characterized in that: The self-healing polymer consists of a shell material and a core material, wherein the core material is emulsified into tiny droplets, and a polymerization reaction is carried out on the surface of the core material to form microcapsules coated with the shell material, and self-healing polymer microcapsules are obtained after washing and drying; the core material of the self-healing polymer is a two-component polyurethane, and the shell material is polyurea.

7. The low VOC waterborne polyurethane industrial paint according to claim 6, characterized in that: The silane quaternary ammonium salt forms a chemical bond with a substrate through a silane group, and is prepared by adding the silane quaternary ammonium salt to a waterborne polyurethane prepolymer and uniformly dispersing the mixture under stirring, wherein the stirring temperature is 40-50° C. and the stirring speed is 200-500 r / min. The prepared silane quaternary ammonium salt is used as an antibacterial agent, and the pH value is 6.0-7.

5.

8. The low VOC waterborne polyurethane industrial paint according to claim 7, characterized in that: The photosensitive curing agent is 2-hydroxy-4'-(2-hydroxyethoxy)benzophenone, and the curing light source is a UV lamp with an energy density of 100-200 mW / cm 2 , wavelength range is 320-400nm, curing temperature is 25-30℃, and curing time is 2-10 seconds.

9. The low VOC waterborne polyurethane industrial paint according to claim 8, characterized in that: The indium tin oxide is an infrared reflective pigment with a particle size of 20-100 nanometers and an infrared reflection band ranging from 750-2500 nm.

10. A method for preparing a low VOC waterborne polyurethane industrial paint according to any one of claims 1 to 9, characterized in that: Here are the steps: 1) weighing waterborne polyurethane emulsion, fluoride-based nanoparticles, aliphatic isocyanate, self-healing polymer, carbon nanotubes, silane quaternary ammonium salt, photosensitive curing agent, indium tin oxide, polydimethylsiloxane, zinc pyrithione, polyether siloxane and ammonium tripolyphosphate according to weight parts for standby use; 2) Raw material pretreatment: the carbon nanotubes are mixed with deionized water and uniformly dispersed by an ultrasonic disperser at 25-30° C. for 20-30 minutes to prevent the carbon nanotubes from agglomerating and form a stable suspension; and the fluoride-based nanoparticles are dispersed in deionized water by a high-shear mixer at 25-30° C. for 10-15 minutes at high speed; 3) Preparation of emulsion base: Adding waterborne polyurethane emulsion as base into a reaction kettle, and stirring at a stirring speed of 500-800 r / min, and controlling the stirring temperature at 25-35° C. to obtain polyurethane emulsion; 4) slowly adding the weighed silane quaternary ammonium salt to the polyurethane emulsion under continuous stirring, and adding the weighed zinc pyrithione under stirring, stirring for 10-15 minutes to form a coating system, and adding the photosensitive curing agent and indium tin oxide to the coating system in the form of a uniformly dispersed slurry, using a high-speed stirrer to disperse at a speed of 800-1200 r / min, maintaining the stirring time for 15-20 minutes, and controlling the temperature at 30-40° C.; 5) adding a polyether siloxane leveling agent to the coating system of step 4), controlling the stirring speed at 300-600 r / min, slowly adding a polydimethylsiloxane defoamer under stirring, controlling the temperature at 25-30° C., and stirring for 5-10 minutes to obtain an emulsion system; 6) Add the self-healing polymer to the emulsion system and stir at 100-300 r / min. After stirring for 10-20 minutes, slowly add ammonium tripolyphosphate for dispersion, maintain the temperature at 30-35°C, and stir for 15-30 minutes; and gradually add aliphatic isocyanate to the emulsion system and stir to increase the crosslinking density. After all the raw materials are added, continue stirring for 30 minutes, let stand at room temperature for 1-2 hours for degassing, and obtain the prepared waterborne polyurethane industrial paint.

Images