Water-based protective coating for photovoltaic polyurethane composite material frame

Abstract

The invention relates to the photovoltaic related field, in particular to a water-based protective coating for a photovoltaic polyurethane composite material framework, which is prepared from the following raw materials: a water-based hydroxyl acrylic emulsion, a water-based PUD dispersion, a pigment, a filler, deionized water, a rheological additive, a defoaming agent, a base material wetting agent, a dispersing agent, a flatting agent, an anti-ultraviolet additive, HDI isocyanate and a PGDA cosolvent. The cold splicing technology of the water-based hydroxyl acrylic emulsion and the water-based PUD dispersoid is used, operation is easy and convenient, the HDI curing agent is matched, the construction performance is excellent, a paint film is flexible, the adhesive force with a polyurethane composite material is good, the weather resistance is good, and salt mist resistance and impact resistance are achieved. The coating can be diluted with water for construction, is low in VOC emission and environment-friendly, and can effectively prolong the service life of a photovoltaic polyurethane composite material frame.

Description

Technical Field

[0001] The invention relates to photovoltaic related fields, in particular to a water-based protective coating for a photovoltaic polyurethane composite material frame. Background Art

[0002] In the photovoltaic industry, the frame is an irreplaceable component. Traditional photovoltaic frames are made of metal materials such as aluminum alloy or steel, which have problems such as heavy weight, difficult installation, and poor weather resistance. Therefore, the development and use of new materials have received more and more attention. Among them, polyurethane composite fiber has good weather resistance and anti-aging properties, is light in weight and easy to install, and can be customized. It has distinctive characteristics and outstanding performance, and is an excellent choice for the new generation of photovoltaic frame materials.

[0003] Although polyurethane composite frames have many advantages, they are still damaged by the environment in actual use. For example, in desert areas or some high-altitude areas, the impact of sunlight and ultraviolet rays on the material is very large, and in offshore areas, the damage to the material by wind and sea water cannot be underestimated. Therefore, adding a protective coating to the polyurethane composite frame to isolate it from various environmental pollution factors can effectively protect the frame from damage and greatly extend the service life of photovoltaic equipment.

[0004] Existing protective coating products are mainly solvent-based, which emit a large amount of organic solvents during construction, have a great impact on the environment, and are poor in environmental protection. Summary of the invention

[0005] The purpose of the present invention is to provide an aqueous protective coating for a photovoltaic polyurethane composite material frame to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a water-based protective coating for a photovoltaic polyurethane composite material frame, comprising two components A and B, wherein the component A is prepared from the following raw materials by weight: 50 parts of water-based hydroxy acrylic emulsion, 9 parts of water-based PUD dispersion, 20 parts of titanium dioxide, 10 parts of 800-mesh precipitated barium sulfate, 1 part of acrylic copolymer dispersant, 1 part of polyurethane type rheological additive, 0.5 parts of modified organic silicon substrate wetting agent, 6.6 parts of deionized water, 0.6 parts of organic silicon defoaming agent, 0.3 parts of modified organic silicon leveling agent and 1 part of ultraviolet absorber; wherein the acrylic copolymer dispersant has a low ion concentration and is particularly good at dispersing inorganic pigments, and its main reaction mechanism is to disperse and stabilize pigment particles by utilizing electrostatic repulsion and steric hindrance effect; the polyurethane type rheological additive contains both It has hydrophilic groups and lipophilic groups, so it has the characteristics of a surfactant. The water in the emulsion makes it form micelles and form a network structure with the emulsion particles to achieve a thickening effect. The present invention uses a modified silicone type wetting agent and leveling agent, which can greatly reduce the surface tension of the system, provide good wetting ability and leveling ability, so that the coating can be evenly distributed on the surface of the substrate, improve the adhesion and flatness of the paint film, and make the paint film more firm and beautiful. After the silicone defoamer is added to the coating system, its molecules can be quickly arranged on the gas-liquid surface, thereby reducing the surface tension. When the surface tension is lower than the surface tension of the foaming solution, it is difficult to produce foam. The ultraviolet absorber can be evenly distributed in the water-based paint system. When the paint film is exposed to the sun, the ultraviolet absorbing auxiliary agent can convert the ultraviolet rays in the sunlight into heat energy, thereby avoiding the damage of the ultraviolet rays to the paint film and improving the weather resistance of the paint film.

[0007] Component B is prepared from the following raw materials by weight: 72 parts of HDI type isocyanate and 28 parts of PGDA.

[0008] Preferably, the water-based hydroxyl acrylic emulsion uses a water-based hydroxyl acrylic emulsion with a hydroxyl value of 82 as the main film-forming material, which is suitable for a wear-resistant, chemical-resistant, and weather-resistant two-component water-based industrial paint anti-corrosion system, can meet the requirements of high film thickness and no blistering, and has good compatibility with other types of emulsions.

[0009] Preferably, the aqueous PUD dispersion adopts an aqueous polyurethane dispersion PUD emulsion with a hydroxyl value of 105, which has good compatibility with aqueous hydroxypropyl emulsion and balanced performance, especially excellent adhesion to polyurethane composite materials. The hydroxyl groups it carries can also be cross-linked with the HDI curing agent to form a network structure with the hydroxypropyl emulsion, thereby improving the resistance and weather resistance of the paint film.

[0010] Preferably, the titanium dioxide powder adopts highly weather-resistant rutile titanium dioxide powder, wherein the surface of the titanium dioxide powder is coated with thickened silicon and aluminum films, thereby being able to well resist the influence of adverse media such as sunlight on the titanium dioxide powder body, thereby greatly improving the weather resistance of the titanium dioxide powder.

[0011] Preferably, a method for preparing a water-based protective coating for a photovoltaic polyurethane composite material frame comprises the following steps:

[0012] Step 1, 50 parts of aqueous hydroxy acrylic emulsion, 9 parts of aqueous PUD dispersion, 20 parts of titanium dioxide pigment, 10 parts of 800 mesh precipitated barium sulfate, 1 part of acrylic copolymer dispersant, 1 part of polyurethane type rheological additive, 0.5 parts of modified silicone substrate wetting agent, 6.6 parts of deionized water, 0.6 parts of silicone defoamer, 0.3 parts of modified organosilane leveling agent, 1 part of ultraviolet absorber are added to the batching kettle in sequence, and stirred at a high speed of 1000 rpm for 20 minutes to prepare a premixed slurry;

[0013] Step 2, further blending and grinding the premixed slurry after stirring in step 1 on a sand mill until the fineness is less than 30 um, and then testing the performance to meet the index requirements to obtain component A;

[0014] Step 3, 72 parts of HDI isocyanate and 28 parts of PGDA are added to the batching kettle in sequence, and the performance is tested after high-speed stirring at 1500 rpm for 30 minutes, and the performance meets the index requirements to obtain component B;

[0015] Step 4: When using, prepare the components according to the weight ratio of component A: component B = 7:1, mix 70 parts of component A and 10 parts of component B evenly, then add appropriate amount of deionized water, and stir to obtain a water-based protective coating.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention uses water-based hydroxy acrylic emulsion as the main film-forming resin. The hydroxyl groups contained in the water-based hydroxy acrylic emulsion and the HDI isocyanate curing agent produce a cross-linking reaction to form a network structure, which provides good resistance and protection for the paint film, and can improve the drying performance of the paint film, and has a low VOC content.

[0018] 2. The present invention uses water-based PUD dispersion in the main film-forming resin and screens out the best ratio between it and hydroxy acrylic emulsion. The water-based PUD dispersion provides the key adhesion of the paint film to the polyurethane composite material, improves the flexibility of the paint film, and resists cracking and impact. The ratio of water-based PUD to hydroxy acrylic emulsion needs to be accurate. If the amount of PUD is insufficient, the adhesion will be poor, and if it is too much, the drying speed will be slow, and the cost of the coating product will increase.

[0019] 3. The present invention uses a modified organic silicon substrate wetting agent in the formula, which can reduce the surface tension of the coating, make the coating easy to wet, and improve the adhesion of the coating film and the polyurethane composite substrate.

[0020] 4. The present invention uses an anti-ultraviolet additive for water-based paint, which can convert ultraviolet rays in sunlight into heat energy when the paint film is irradiated, thereby avoiding the breakage of the molecular chains of the paint film-forming material and extending the service life of the coating film, thereby extending the protection period of the polyurethane composite material frame.

[0021] 5. The water-based protective coating prepared by the present invention can be applied to the protection of photovoltaic polyurethane composite material frames. Compared with ordinary water-based polyurethane protective paints, the paint film has outstanding advantages in adhesion to the polyurethane composite material and weather resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the preparation process of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] The invention provides a technical solution: a water-based protective coating for a photovoltaic polyurethane composite material frame, comprising two components A and B, wherein the component A is prepared from the following raw materials by weight: 50 parts of water-based hydroxy acrylic emulsion, 9 parts of water-based PUD dispersion, 20 parts of titanium dioxide, 10 parts of 800-mesh precipitated barium sulfate, 1 part of acrylic copolymer dispersant, 1 part of polyurethane type rheological additive, 0.5 part of modified organic silicon substrate wetting agent, 6.6 parts of deionized water, 0.6 parts of organic silicon defoaming agent, 0.3 parts of modified organic silicon leveling agent and 1 part of ultraviolet absorber; wherein the acrylic copolymer dispersant has a low ion concentration and is particularly good in dispersibility for inorganic pigments, and its main reaction mechanism is to disperse and stabilize pigment particles by utilizing electrostatic repulsion and steric hindrance effect; the polyurethane type rheological additive contains hydrophilic groups in its molecular structure at the same time. The present invention uses modified organic silicon type wetting agent and leveling agent, which can greatly reduce the surface tension of the system, provide good wetting ability and leveling ability, so that the coating film can be evenly distributed on the surface of the substrate, improve the adhesion and flatness of the paint film, and make the paint film more firm and beautiful; after the organic silicon defoamer is added to the coating system, its molecules can be quickly arranged on the gas-liquid surface, thereby reducing the surface tension. When the surface tension is lower than the surface tension of the foaming solution, it is difficult to produce foam; the ultraviolet absorber can be evenly distributed in the water-based paint system. When the paint film is exposed to the sun, the ultraviolet absorbing auxiliary agent can convert the ultraviolet rays in the sunlight into heat energy, thereby avoiding the damage of the paint film to the ultraviolet rays and improving the weather resistance of the paint film.

[0026] Furthermore, the water-based hydroxyl acrylic emulsion uses a water-based hydroxyl acrylic emulsion with a hydroxyl value of 82 as the main film-forming material. It is suitable for a two-component water-based industrial paint anti-corrosion system that is wear-resistant, chemical-resistant, and weather-resistant. It can meet the requirements of high film thickness and no blistering, and has good compatibility with other types of emulsions.

[0027] Furthermore, the water-based PUD dispersion adopts a water-based polyurethane dispersion PUD emulsion with a hydroxyl value of 105, which has good compatibility with the water-based hydroxypropyl emulsion and balanced performance, especially excellent adhesion to polyurethane composite materials. The hydroxyl groups it carries can also be cross-linked with the HDI curing agent to form a network structure with the hydroxypropyl emulsion, thereby improving the resistance and weather resistance of the paint film.

[0028] Furthermore, titanium dioxide uses highly weather-resistant rutile titanium dioxide, in which the surface of titanium dioxide is thickened with silicon and aluminum coatings, so that it can effectively resist the influence of adverse media such as sunlight on the titanium dioxide body, greatly improving the weather resistance of titanium dioxide.

[0029] Specifically, the water-based protective coating prepared by the present invention can be applied to the protection of photovoltaic polyurethane composite material frames. Compared with ordinary water-based polyurethane protective paints, the paint film has outstanding advantages in adhesion to the polyurethane composite material and weather resistance. According to the ratio of A\B=7\1, the paint film performance is as follows:

[0030]

[0031]

[0032] Example 2

[0033] See also Figure 1 A method for preparing a water-based protective coating for a photovoltaic polyurethane composite material frame, comprising the following steps:

[0034] Step 1, 50 parts of aqueous hydroxy acrylic emulsion, 9 parts of aqueous PUD dispersion, 20 parts of titanium dioxide pigment, 10 parts of 800 mesh precipitated barium sulfate, 1 part of acrylic copolymer dispersant, 1 part of polyurethane type rheological additive, 0.5 parts of modified silicone substrate wetting agent, 6.6 parts of deionized water, 0.6 parts of silicone defoamer, 0.3 parts of modified organosilane leveling agent, 1 part of ultraviolet absorber are added to the batching kettle in sequence, and stirred at a high speed of 1000 rpm for 20 minutes to prepare a premixed slurry;

[0035] Step 2, further blending and grinding the premixed slurry after stirring in step 1 on a sand mill until the fineness is less than 30 um, and then testing the performance to meet the index requirements to obtain component A;

[0036] Step 3, 72 parts of HDI isocyanate and 28 parts of PGDA are added to the batching kettle in sequence, and the performance is tested after high-speed stirring at 1500 rpm for 30 minutes, and the performance meets the index requirements to obtain component B;

[0037] Step 4: When using, prepare the components according to the weight ratio of component A: component B = 7:1, mix 70 parts of component A and 10 parts of component B evenly, then add appropriate amount of deionized water, and stir to obtain a water-based protective coating.

[0038] The water-based hydroxy acrylic emulsion of the present invention provides a hydroxyl reactive group, which reacts with an HDI type isocyanate curing agent to form a network structure, thereby generating a barrier effect on the surface of the polyurethane composite frame, effectively blocking the penetration of harmful factors, and extending the service life of the photovoltaic frame.

[0039] The mixed water-based PUD dispersion provides adhesion of the coating film to the polyurethane composite material. Its soft linear chain segments increase the flexibility of the paint film and enhance its impact resistance. At the same time, the hydroxyl groups it contains can also participate in the cross-linking reaction with HDI and become part of the network structure, protecting the polyurethane composite material framework.

[0040] This product uses water-based raw materials and can be diluted with water for construction. It has low VOC emissions and is green and environmentally friendly.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A water-based protective coating for a photovoltaic polyurethane composite material frame, characterized in that: The invention comprises two components, A and B, wherein the component A is prepared from the following raw materials by weight: 50 parts of aqueous hydroxy acrylic emulsion, 9 parts of aqueous PUD dispersion, 20 parts of titanium dioxide, 10 parts of 800-mesh precipitated barium sulfate, 1 part of acrylic copolymer dispersant, 1 part of polyurethane type rheological additive, 0.5 parts of modified organic silicon substrate wetting agent, 6.6 parts of deionized water, 0.6 parts of organic silicon defoaming agent, 0.3 parts of modified organic silicon leveling agent and 1 part of ultraviolet absorber; Component B is prepared from the following raw materials by weight: 72 parts of HDI type isocyanate and 28 parts of PGDA.

2. The water-based protective coating for photovoltaic polyurethane composite material frame according to claim 1, characterized in that: The water-based hydroxyl acrylic emulsion uses a water-based hydroxyl acrylic emulsion with a hydroxyl value of 82 as a main film-forming material.

3. The aqueous protective coating for photovoltaic polyurethane composite material frame according to claim 1, characterized in that: The water-based PUD dispersion adopts a water-based polyurethane dispersion PUD emulsion with a hydroxyl value of 105.

4. The aqueous protective coating for photovoltaic polyurethane composite material frame according to claim 1, characterized in that: The titanium dioxide powder adopts highly weather-resistant rutile titanium dioxide powder, wherein the surface of the titanium dioxide powder is coated with thick silicon and aluminum.

5. A method for preparing a water-based protective coating for a photovoltaic polyurethane composite material frame according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, 50 parts of aqueous hydroxy acrylic emulsion, 9 parts of aqueous PUD dispersion, 20 parts of titanium dioxide pigment, 10 parts of 800 mesh precipitated barium sulfate, 1 part of acrylic copolymer dispersant, 1 part of polyurethane type rheological additive, 0.5 parts of modified silicone substrate wetting agent, 6.6 parts of deionized water, 0.6 parts of silicone defoamer, 0.3 parts of modified organosilane leveling agent, 1 part of ultraviolet absorber are added to the batching kettle in sequence, and stirred at a high speed of 1000 rpm for 20 minutes to prepare a premixed slurry; Step 2, further blending and grinding the premixed slurry after stirring in step 1 on a sand mill until the fineness is less than 30 um, and then testing the performance to meet the index requirements to obtain component A; Step 3, 72 parts of HDI isocyanate and 28 parts of PGDA are added to the batching kettle in sequence, and the performance is tested after high-speed stirring at 1500 rpm for 30 minutes, and the performance meets the index requirements to obtain component B; Step 4: When using, prepare the components according to the weight ratio of component A: component B = 7:1, mix 70 parts of component A and 10 parts of component B evenly, then add appropriate amount of deionized water, and stir to obtain a water-based protective coating.

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