High-weatherability water-based paint for glass fiber composite without pretreatment, preparation method and application thereof

Abstract

The application discloses a high-weatherability water-based paint for glass fiber composite materials without pretreatment, a preparation method and application thereof. The high-weatherability water-based paint is a two-component paint, wherein the raw materials of the first component contain, in parts by weight, 30-80 parts of water-based acrylic resin, 5-20 parts of silane hydrolysis oligomer, 2-10 parts of organic solvent, 2.1-30 parts of additive, 5-25 parts of filler, 5-15 parts of nano color paste and 5-25 parts of deionized water; and the raw materials of the second component contain, in parts by weight, 70-90 parts of isocyanate curing agent and 10-30 parts of solvent. The scheme can well solve the problems that a glass fiber reinforced composite structure (such as a photovoltaic frame) needs to be pretreated before being coated, and the structure after being coated is difficult to have good adhesion and outdoor weather resistance in an extreme environment.

Description

Technical Field

[0001] The present invention relates to the technical field of water-based coatings for glass fiber composite materials, and more specifically to a highly weather-resistant water-based coating for glass fiber composite materials without pre-treatment, and a preparation method and application thereof. Background Art

[0002] Traditional, high-energy-consuming energy sources are gradually being replaced by green, sustainable new energy sources. In the materials sector, new glass fiber composites offer excellent properties such as lightweight, high strength, insulation, PID resistance, aging resistance, corrosion resistance, fire resistance, high and low temperature resistance, design flexibility, and cost-effectiveness. These glass fiber composite substrates place high demands on coatings, requiring them to withstand damage and destruction caused by various extreme weather conditions (such as extreme heat and cold, wind and sandstorms), while also providing high weather resistance against long-term outdoor exposure.

[0003] Driven by the dual carbon policy, the coatings industry faces significant challenges. Water-based coatings, which use water as a solvent, can conserve significant amounts of petroleum resources, and feature low VOC emissions and minimal air pollution. They are being vigorously promoted and widely used in the automotive, wood, construction, and waterproofing sectors. However, for specialized materials such as glass fiber reinforced composites (GFRPs), the pultrusion process used to form these materials leaves a significant amount of release agent residue on their surfaces. Furthermore, the wide variety of resins and glass fibers used in profiles results in significant variations in surface energy. Traditional water-based coatings have difficulty adhering to these surfaces, necessitating additional substrate pre-treatment processes such as grinding, flaring, and sandblasting. This increases production costs and reduces efficiency, significantly hindering the development of the photovoltaic industry.

[0004] Furthermore, mass-produced glass fiber reinforced composite frames are composed of approximately 70-80% glass fiber and 20-30% organic resin. The aromatic organic resin used in these panels exhibits noticeable yellowing upon exposure to sunlight, while traditional water-based coatings lack the adhesion and weather resistance required for long-term outdoor use of photovoltaic panel frames. Summary of the Invention

[0005] Based on the above facts, the purpose of the present invention is to provide a highly weather-resistant water-based coating for glass fiber composite materials without pre-treatment, as well as its preparation method and application, so as to solve the problem that some glass fiber reinforced composite materials structures (such as photovoltaic frames, etc.) need to be pre-treated before they can be better painted, and the painted structures are difficult to have good adhesion and outdoor weather resistance in extreme environments.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a highly weather-resistant water-based coating for glass fiber composite materials without pre-treatment, wherein the highly weather-resistant water-based coating is a two-component coating, wherein:

[0008] The raw materials of the first component include, by weight:

[0009] 30-80 parts of water-based acrylic resin, 5-20 parts of silane hydrolyzed oligomer, 2-10 parts of organic solvent, 2.1-30 parts of additives, 5-25 parts of filler, 5-15 parts of nano color paste and 5-25 parts of deionized water;

[0010] The raw materials of the second component include, by weight:

[0011] 70-90 parts of isocyanate curing agent and 10-30 parts of solvent.

[0012] Furthermore, the silane hydrolysis oligomer is an oligomer obtained by reacting an organic functional silane monomer and silica sol in the presence of an acid catalyst and an organic solvent using a sol-gel method.

[0013] Furthermore, the reaction temperature is 40-80° C. and the reaction time is 1-3 h.

[0014] Furthermore, in the method for preparing the silane hydrolyzed oligomer by the sol-gel method, the amount of the organic functional silane monomer is 20-60 parts, the amount of silica sol is 5-15 parts, the amount of acid catalyst is 1-5 parts, and the amount of organic solvent is 10-20 parts.

[0015] Furthermore, the preparation of the silane hydrolysis oligomer comprises the following steps:

[0016] Premixing the organofunctional silane monomer and the organic solvent at a rotation speed of 400-700 rpm to obtain a premixed solution;

[0017] After the temperature of the premixed liquid is raised to 80° C., silica sol and acid catalyst are added dropwise respectively, and the addition of silica sol and acid catalyst is controlled to be completed within 0.5 h and 1 h, respectively. Finally, the obtained mixture is kept warm and reacted for 1 h, and then subjected to rotary evaporation at 40° C. to remove small molecular by-products and mature to obtain the silane hydrolysis oligomer.

[0018] Furthermore, the filler is one or more of spherical fillers, flake fillers, fibrous fillers and rod-shaped fillers.

[0019] Furthermore, the fibrous filler is selected from one or more of wollastonite, feldspar powder, brucite and pyrophyllite.

[0020] Furthermore, the rod-shaped filler is selected from one or more of carbon nanotubes, graphene, rod-shaped ceria, rod-shaped alumina and rod-shaped aluminum silicate.

[0021] Furthermore, the spherical filler is selected from one or more of barium sulfate, calcium carbonate, quartz powder and fumed silica.

[0022] Furthermore, the particle size of the spherical filler is 350 mesh-2500 mesh.

[0023] Furthermore, the flaky filler is selected from one or more of kaolin, talc, mica, graphite powder, bentonite and attapulgite.

[0024] Furthermore, the particle size of the flaky filler is 325 mesh-2500 mesh.

[0025] Furthermore, the filler is a mixture of spherical fillers and flake fillers in a mass ratio of 1:1-10:1.

[0026] Furthermore, the mass ratio of the water-based acrylic resin to the filler is (2-8):1.

[0027] Furthermore, the auxiliary agent contains 1-10 parts of ultraviolet light absorber and 1-10 parts of ultraviolet light stabilizer.

[0028] In another aspect, the present invention provides a method for preparing the highly weather-resistant water-based coating as described above, the preparation method comprising the following steps:

[0029] Preparation of the first component:

[0030] Dissolving the water-based acrylic resin and silane hydrolyzed oligomer in an organic solvent, mixing them evenly, then adding an additive, a filler, and a nano-color paste, mixing them evenly, and adjusting the viscosity with deionized water to obtain the first component;

[0031] Preparation of the second component:

[0032] The isocyanate curing agent is mixed with a solvent to obtain the second component.

[0033] In another aspect, the present invention provides use of the highly weather-resistant water-based coating as described above in coating of glass fiber reinforced composite materials.

[0034] Furthermore, the substrate of the glass fiber reinforced composite material structure is not pre-treated before coating.

[0035] Furthermore, the structure is a photovoltaic frame.

[0036] In another aspect, the present invention provides a glass fiber reinforced composite material structure, which comprises a substrate and a coating formed by the above-mentioned highly weather-resistant water-based coating applied on the surface of the substrate.

[0037] Furthermore, the structure is a photovoltaic frame.

[0038] In yet another aspect, the present application provides a method for preparing the glass fiber reinforced composite structure as described above, comprising the following steps:

[0039] The high-weatherability water-based paint is applied on a substrate to form a coating layer, wherein the substrate is not pretreated before painting.

[0040] The beneficial effects of the present application are as follows:

[0041] In the water-based paint provided in the present application, by introducing an organosilane hydrolysis oligomer, the cross-linking strength of the paint film is enhanced while the excellent adhesion between the coating and the substrate is ensured, and the ability of the coating to resist external damage is improved; in addition, the preferred specific filler can release the internal stress generated by the cross-linking of the paint film, so that the paint film has the characteristics of hardness and toughness, and further preferably, the accumulation shielding effect of spherical particles of different particle sizes, the covering effect of flaky fillers on the surface of the coating, and the synergistic effect of water-based acrylic resin make the coating well increase the chemical resistance and excellent ultraviolet resistance.

[0042] The VOC of the water-based paint provided in the present application is less than 200 g / L, and after the glass fiber composite material is directly painted without pretreatment, the obtained coating can provide "0" level adhesion and has outdoor severe weather resistance; in addition, the water-based paint is easy to construct and is very suitable for the coating of the surface of the glass fiber composite material. DETAILED DESCRIPTION

[0043] In order to more clearly illustrate the present application, the present application will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the specific descriptions below are illustrative and not limiting, and should not limit the protection scope of the present application.

[0044] For the glass fiber reinforced pultruded composite structure (such as a photovoltaic frame), there are the following problems: 1) before painting, the structure needs to be pretreated (including sanding, burning, sandblasting, etc.) to improve the adhesion of the coating, which increases the production cost and reduces the production efficiency; 2) in the glass fiber reinforced aromatic organic resin composite structure, the aromatic organic resin is prone to yellowing after light exposure, and the outdoor weather resistance and adhesion cannot meet the long-term outdoor use requirements, etc. One specific embodiment of the present application provides a high-weatherability water-based paint for pretreatment-free glass fiber composite material, which is a two-component paint, wherein,

[0045] The raw materials of the first component include, by weight:

[0046] 30-80 parts of water-based acrylic resin, 5-20 parts of silane hydrolysis oligomer, 2-10 parts of organic solvent, 2.1-30 parts of auxiliary agent, 5-25 parts of filler, 5-15 parts of nano color paste and 5-25 parts of deionized water;

[0047] The raw materials of the second component comprise, by weight parts:

[0048] 70-90 parts of isocyanate curing agent and 10-30 parts of solvent.

[0049] The high-weather-resistant water-based paint provided in the technical solution is particularly suitable for coating the surface of a glass fiber reinforced composite structure (such as a photovoltaic frame), and the coating obtained after coating has good appearance decoration, excellent adhesion (good mechanical properties and adhesion, etc.), and can also enable the glass fiber reinforced composite structure after coating to meet the weather resistance use requirements in different outdoor harsh conditions.

[0050] In the technical solution, the silane in the silane hydrolysis oligomer will undergo a hydrolysis condensation reaction during the film formation of the water-based paint, the generated silicon hydroxyl group can be anchored to the substrate, and the organic functional group (such as a vinyl group, an amino group, etc.) at the other end of the structure can react with the resin to form a covalent bond, for example, an amino silane can undergo ring-opening reaction with an epoxy group in the epoxy resin to form a -NH-CH2- covalent bond, a vinyl silane can undergo chain extension reaction with a group having an unsaturated double bond on the resin to form a -CH2-CH2- covalent bond, etc., thereby playing a good bridging role between the substrate and the coating, enabling the coating to have excellent adhesion to various glass fiber reinforced composite substrates without prior treatment, and even ignoring the presence of a release agent on the surface of the glass fiber reinforced composite, greatly simplifying the coating process and improving production efficiency; secondly, the coating formed through chemical reaction constitutes a dense network structure of organic-inorganic hybrid crosslinking, which can effectively improve the chemical resistance and aging resistance of the coating, and further meet the weather resistance use requirements of the glass fiber reinforced composite structure after coating in different outdoor harsh conditions.

[0051] In some examples, the silane hydrolysis oligomer is obtained by reacting an organic functional silane monomer and a silica sol in the presence of an acid catalyst and an organic solvent using a sol-gel method.

[0052] In some examples, the reaction temperature is 40-80°C, and the reaction time is 1-3h.

[0053] In some preferred examples, the reaction temperature is 80°C, and the reaction time is 1h.

[0054] In the present embodiment, the silane hydrolysis oligomer preferably has a solid content of 20%-60%.

[0055] In some specific examples, in the method of preparing silane hydrolysis oligomers by a sol-gel method, the amount of the organic functional silane monomer is 20-60 parts, the amount of silica sol is 5-15 parts, the amount of the acid catalyst is 1-5 parts, and the amount of the organic solvent is 10-20 parts.

[0056] The silane hydrolyzed oligomer prepared by the above method can better improve the adhesion between the coating obtained after the above water-based coating is applied to the glass fiber reinforced composite material (without pretreatment) and the substrate, the coating hardness and the long-term weather resistance of the coating.

[0057] In some embodiments, the organofunctional silane monomer includes but is not limited to compounds selected from the following:

[0058] For example, the organofunctional silane monomer may be a monofunctional organosilane, i.e., an organosilane containing one hydrolyzable group. More specific examples include trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, triethylethoxysilane, vinyldimethylmethoxysilane, vinyldimethylethoxysilane, γ-aminopropyldimethylmethoxysilane, or γ-glycidoxypropyldimethylmethoxysilane.

[0059] Alternatively, the organofunctional silane monomer is a bifunctional silane, i.e., an organosilane containing two hydrolyzable groups. Specific examples include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, or γ-aminopropylmethyldimethoxysilane.

[0060] Alternatively, the organofunctional silane monomer is a trifunctional silane, i.e., an organosilane containing three hydrolyzable groups. Specific examples include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, or γ-(2,3-epoxypropoxy)propyltrimethoxysilane (also known as γ-glycidoxypropyltrimethoxysilane).

[0061] Alternatively, the organofunctional silane monomer is a tetrafunctional silane, i.e., an organosilane containing four hydrolyzable groups, such as tetramethyl silicate, tetraethyl silicate (also known as tetraethoxysilane), and the like.

[0062] In some specific examples of the present embodiment, one or more than one organic functional silane monomer can be selected to prepare the silane hydrolysis oligomer. When the organic functional silane monomer is selected from two or more than two combinations, preferred combination examples include a combination of methyltrimethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane, a combination of methyltrimethoxysilane and γ-epoxypropoxypropyldimethylmethoxysilane, a combination of tetraethyl silicate and γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and a combination of methyltriethoxysilane, tetraethyl silicate and γ-(2,3-epoxypropoxy)propyltrimethoxysilane (the mass ratio of the three is preferably (6-8):1:(1.5-5)).

[0063] In the present technical solution, the silica sol is preferably an aqueous silica sol. In some examples, the silica sol is an acidic silica sol or an alkaline silica sol. Exemplary silica sols include, but are not limited to, ST-OXS, ST-O, ST-OUP, ST-PS-SO, etc. from Showa Denko.

[0064] In some examples, the acid catalyst is selected from one or more of dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, phosphoric acid, formic acid, acetic acid and citric acid.

[0065] In some examples, in the method for preparing the silane hydrolysis oligomer by the sol-gel method, the organic solvent is selected from alcohol ether solvents. For example, one or more of ethanol, isopropanol, n-butanol, isobutanol, propylene glycol methyl ether, ethylene glycol butyl ether, dipropylene glycol monomethyl ether, diethylene glycol monobutyl ether and dipropylene glycol monobutyl ether.

[0066] In yet some more specific examples, the preparation of the silane hydrolysis oligomer includes the following steps:

[0067] The organic functional silane monomer and the organic solvent are premixed at a rotation speed of 400-700 rpm to obtain a premixed solution;

[0068] After the temperature of the premixed solution is raised to 80°C, the silica sol and the acid catalyst are added dropwise, respectively, and the silica sol and the acid catalyst are controlled to be added dropwise within 0.5 h and 1 h, respectively. Finally, the obtained mixture is incubated and continuously reacted for 1 h, followed by 40°C rotary evaporation to remove small molecular byproducts, aging to obtain the silane hydrolysis oligomer.

[0069] In yet some more specific examples, the preparation of the silane hydrolysis oligomer includes the following steps:

[0070] First, add 20-60 parts of organic functional silane monomer and 10-20 parts of alcohol ether solvent into a three-necked flask and premix at a speed of 400-700 rpm; then take 5-15 parts of aqueous silica sol and 1-5 parts of acid catalyst into a dropping funnel, and add them dropwise after the temperature of the premixed liquid rises to 80°C. The aqueous silica sol and acid catalyst are controlled to be added dropwise within 0.5h and 1h, respectively. Finally, the resulting mixture is kept warm and reacted for 1h before being rotary evaporated at 40°C to remove small molecular by-products. The silane hydrolysis oligomer is obtained by aging overnight.

[0071] In some examples, the silane hydrolyzed oligomer includes but is not limited to one selected from the group consisting of the silane hydrolyzed oligomer prepared as above, KR-513, X-41-1805, etc. Preferably, the silane hydrolyzed oligomer is the silane hydrolyzed oligomer prepared as above.

[0072] In some examples, the content of the silane hydrolyzed oligomer in the raw materials of the first component includes but is not limited to 10-20 parts, 10-15 parts, 5-15 parts, 15 parts, etc.

[0073] In some examples, the water-based acrylic resin can be selected from one or more combinations of water-based hydroxyl acrylic resin, epoxy-modified water-based acrylic resin, polyurethane-modified water-based acrylic resin, silicone-modified water-based acrylic resin, organic fluorine-modified water-based acrylic resin, alkyd resin-modified hybrid water-based acrylic resin, and nano-modified water-based acrylic resin.

[0074] In some examples, the waterborne hydroxylated acrylic resin has a solid content of 40%-60% and a hydroxyl value of 80-140 mgKOH / g. In more specific examples, the waterborne hydroxylated acrylic resin includes, but is not limited to, Wanhua's Antkote® 2035, Antkote® 2042, Antkote® 2033, and Covestro's Bayhydrol A 2695, Bayhydrol A 2470, and Bayhydrol A 2651.

[0075] Exemplarily, the epoxy-modified waterborne acrylic resin includes, but is not limited to, at least one selected from a graft copolymer of epoxy resin and acrylate, a copolymer of epoxysilane and acrylate, and a copolymer of glycidyl ether (GMA) and acrylate.

[0076] Exemplarily, the polyurethane-modified waterborne acrylic resin includes but is not limited to at least one copolymer of polyurethane and acrylate prepared by reacting one or more of toluene-2,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, trimethylhexane diisocyanate, meta-xylylene diisocyanate, and isophorone diisocyanate with polyol.

[0077] For example, the organosilicon-modified waterborne acrylic resin includes, but is not limited to, at least one selected from the group consisting of polyorganosilane, polyorganosiloxane, polyorganosiloxane and copolymers of acrylates.

[0078] Exemplary organic fluorine-modified waterborne acrylic resins include, but are not limited to, waterborne acrylic resins graft-modified with copolymers of one or more fluoroolefins selected from tetrafluoroethylene, vinylidene fluoride, and vinyl fluoride, and alkyl vinyl ethers or esters. Examples include, but are not limited to, commercially available HD-8669, HD-827, and HD-830 from Shanghai Xunda New Materials.

[0079] In some preferred examples, the water-based acrylic resin is the above-mentioned water-based hydroxy acrylic resin, or the mixture of the above-mentioned water-based hydroxy acrylic resin and an organic fluorine-modified water-based acrylic resin. More preferably, it is the mixture of water-based hydroxy acrylic resin and an organic fluorine-modified water-based acrylic resin. At this time, the paint film obtained has more excellent aging resistance and long-term weather resistance. Exemplary, when the water-based acrylic resin is the mixture of the above-mentioned water-based hydroxy acrylic resin and an organic fluorine-modified water-based acrylic resin, the mass ratio of the two is preferably (0.4-5): 1, (0.4-3): 1, (0.4-2.5): 1, (0.4-1): 1, (0.4-0.8): 1, (1.5-5): 1, (1.5-3): 1, (2-3): 1, etc.

[0080] Exemplarily, the alkyd resin modified hybrid waterborne acrylic resin includes but is not limited to at least one alkyd resin modified hybrid waterborne acrylic resin synthesized from at least one of soybean oil fatty acid, tung oil fatty acid, linseed oil fatty acid, tall oil fatty acid, and castor oil fatty acid.

[0081] Exemplarily, the nano-modified water-based acrylic resin includes but is not limited to at least one water-based acrylic resin modified by at least one of nano-silicon dioxide, nano-titanium dioxide, nano-zinc dioxide, nano-calcium carbonate, and nano-ferric oxide.

[0082] In some examples, in the raw materials of the first component of the water-based coating, the weight proportion of the water-based acrylic resin includes but is not limited to 30-60 parts, 50-80 parts, 40-60 parts, 50 parts, etc.

[0083] In some preferred embodiments, the additive contains 1-10 parts of a UV absorber and 1-10 parts of a UV stabilizer. This effectively slows down yellowing, gloss loss, or chalking of the paint film. Exemplary UV absorber contents are 1-5 parts, 1-2 parts, and the like. Exemplary UV stabilizer contents are 1-5 parts, 1-2 parts, and the like.

[0084] For example, the ultraviolet light absorber is selected from at least one of Tinuvin 1130, Tinuvin 1600 and Tinuvin 171.

[0085] For example, the ultraviolet light stabilizer is selected from at least one of Tinuvin 123, Tinuvin 249 and Tinuvin 292.

[0086] In this embodiment, the additives may be optionally supplemented with one or more additional additives, including substrate wetting agents (e.g., Tego Wet 270), leveling agents (e.g., BYK-333), defoamers (e.g., BYK-024), and rheology modifiers (e.g., TegoViscoPlus 3060), depending on actual needs. Those skilled in the art will appreciate that each of these additives has specific uses, and their specific use depends on the formulation and process.

[0087] In some examples, the first component includes 0.05-3 parts of a substrate wetting agent, 0.05-3 parts of a leveling agent, 0.05-3 parts of a defoaming agent, and 0.05-5 parts of a rheological additive.

[0088] For example, the functional filler is selected from one or more of spherical fillers, flake fillers, fibrous fillers, and rod-shaped fillers.

[0089] For example, suitable spherical fillers include, but are not limited to, one or more of barium sulfate, calcium carbonate, quartz powder, and fumed silica.

[0090] For example, suitable plate-like fillers include, but are not limited to, one or more of kaolin, talc, mica, graphite powder, bentonite, and attapulgite.

[0091] Exemplarily, suitable fibrous fillers include, but are not limited to, one or more of wollastonite, feldspar powder, brucite, and pyrophyllite.

[0092] For example, suitable rod-shaped fillers include, but are not limited to, one or more of carbon nanotubes, graphene, rod-shaped ceria, rod-shaped alumina, and rod-shaped aluminum silicate.

[0093] In some examples, the filler is a mixture of spherical fillers and flake fillers. The spherical fillers not only enhance the performance of the paint film but also alleviate the significant internal stress generated by silane hydrolyzed oligomers during the crosslinking reaction. Due to their high specific surface area, flake fillers can provide a physical shielding effect within the paint film, such as reflecting light and blocking water vapor. The synergistic effect of flake and spherical fillers effectively enhances the density of the paint film, thereby improving the various resistance properties of the coating. More importantly, the regular arrangement of these two fillers on the coating surface can significantly reflect and hinder UV damage to the coating, thereby extending the long-term outdoor life of structures coated with the coating (particularly glass fiber reinforced composite structures).

[0094] In some examples, the particle size of the spherical filler is preferably 350 mesh to 2500 mesh, and the particle size of the flake filler is preferably 325 mesh to 2500 mesh. In this case, the obtained coating has better hardness, flexibility and weather resistance.

[0095] The fillers contained in the water-based coating of this embodiment can release the internal stress generated by cross-linking of the paint film, making the paint film hard and tough. In addition, the stacking shielding effect of spherical particles of different particle sizes, the shielding effect of the flaky fillers (reflecting ultraviolet rays), and the synergistic effect of the water-based acrylic resin enable the coating to greatly increase chemical resistance and excellent ultraviolet resistance. In some preferred examples, the mass ratio of the water-based acrylic resin to the filler is (2-8):1. In this case, the above-mentioned effect is better. Exemplarily, the mass ratio of the water-based acrylic resin to the filler includes but is not limited to (2-5):1, (2-4):1, (3-4):1, (3-3.5):1, etc.

[0096] Preferably, the spherical filler is selected from barium sulfate. In some specific examples, the particle sizes of the spherical filler are 350 mesh, 600 mesh, 1000 mesh, 1250 mesh, 2000 mesh, 2500 mesh, etc. from coarse to fine.

[0097] In some preferred examples, the spherical filler is a mixture of barium sulfate with a particle size of 1000 mesh and 2000 mesh. The mixing ratio of the two is preferably (1-3):7, 2:7, etc. Barium sulfate has a high density and is often located at the bottom of the paint film. Since it can reflect light within a certain wavelength range (300-400nm), it can protect the paint film from light aging. The main reason for selecting barium sulfate of different particle sizes is to obtain the optimal paint film density based on the close packing effect of large and small particles.

[0098] Preferably, the flaky filler is selected from mica. In some specific examples, the particle sizes of the flaky filler are 325 mesh, 600 mesh, 800 mesh, 1250 mesh, 2000 mesh, and 2500 mesh, from coarse to fine.

[0099] In some preferred examples, the flaky filler is a mixture of mica with a particle size of 1250 mesh and 2000 mesh. The mixing ratio of the two is preferably (1-3):5, 2:5, etc. Mica has a low density and its own flaky shape, so it is easy to disperse on the surface of the paint film, has a good reflective effect on light and can also block moisture. Since the paint film will have a certain volume shrinkage during the film formation process, the flaky filler cannot be ideally spread on the surface of the paint film. The spatial complementary effect of flaky fillers of different particle sizes can form a good physical barrier on the surface.

[0100] In some preferred examples, the mass ratio of the spherical filler to the flaky filler is 1:1-10:1. Exemplary mass ratios include, but are not limited to, (1-5):1, (1-3):1, (1-2):1, 9:7, and the like. In this case, the resulting paint film exhibits improved surface density, anti-yellowing properties, outdoor weather resistance, and adhesion.

[0101] In some examples, the weight proportion of fillers in the raw materials of the first component of the water-based coating includes, but is not limited to, 10-25 parts, 10-20 parts, 10-16 parts, 15-25 parts, 15-20 parts, 16 parts, and the like.

[0102] In this embodiment, the color and selection of the nano-color paste are not specified; any nano-color paste commonly used in the art for glass fiber composite substrates can be used. In some examples, the nano-color paste includes, but is not limited to, one or more of AQUECO 9000 Water-Based Color Paste - Black, AQUECO 9000 Water-Based Color Paste - White, AQUECO 9000 Water-Based Color Paste - Yellow, and AQUECO 9000 Water-Based Color Paste - Red.

[0103] In this embodiment, the organic solvent in the raw materials of the first component is mainly used to dissolve the water-based acrylic resin. For example, a suitable organic solvent can be an alcohol ether solvent. Exemplarily, the organic solvent in the raw materials of the first component is selected from one or more combinations of ethylene glycol monobutyl ether, n-butanol, isobutanol, ethylene glycol isooctyl ether, propylene glycol methyl ether, dipropylene glycol monobutyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, ethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, and 1-2-propylene glycol diacetate.

[0104] In some examples, the isocyanate curing agent is a hydrophilic polyisocyanate.

[0105] Furthermore, the hydrophilic polyisocyanate is at least one selected from the group consisting of aliphatic isocyanate polymers (including aliphatic isocyanate dimers, aliphatic isocyanate trimers, etc.), aromatic isocyanate polymers (including aromatic isocyanate dimers, aromatic isocyanate trimers, etc.), and alicyclic isocyanate polymers (including alicyclic isocyanate dimers, alicyclic isocyanate trimers, etc.).

[0106] Exemplarily, the aliphatic isocyanate polymer is a polymer of at least one selected from the group consisting of tetramethylene 1,4-diisocyanate, hexamethylene 1,6-diisocyanate, 2,2,4-trimethylhexane 1,6-diisocyanate, ethylene diisocyanate, and 1,12-dodecyl diisocyanate.

[0107] Exemplarily, the alicyclic isocyanate polymer is selected from at least one polymer of the group consisting of isophorone diisocyanate, cyclobutane 1,3-diisocyanate, cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate, methylcyclohexyl diisocyanate, 4,4-methylene dicyclohexyl diisocyanate, and hydrogenated diphenylmethane diisocyanate.

[0108] In some specific examples, the isocyanate curing agent is one or more of Bayhydur Ultra 2655, Bayhydur Ultra 307, Bayhydur Ultra 304, etc., manufactured by Covestro.

[0109] The solvent is mainly used to dissolve the isocyanate curing agent. Exemplarily, the solvent is selected from one or more of n-butanol, isobutanol, ethylene glycol isooctyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, dipropylene glycol monobutyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, ethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, and propylene glycol diacetate (PGDA).

[0110] In some examples, the weight ratio of the first component to the second component raw materials is 100:10-90, preferably 100:20-50, and more preferably 100:40.

[0111] In some examples, the total weight of the raw materials of the first component is 100 parts.

[0112] In some examples, the total weight of the raw materials of the second component is 100 parts.

[0113] According to another embodiment of the present invention, there is provided a method for preparing the highly weather-resistant water-based coating as described above, comprising the following steps:

[0114] Preparation of the first component:

[0115] Dissolving the water-based acrylic resin and silane hydrolyzed oligomer in an organic solvent, mixing them evenly, then adding an additive, a filler, and a nano-color paste, mixing them evenly, and adjusting the viscosity with deionized water to obtain the first component;

[0116] Preparation of the second component:

[0117] The isocyanate curing agent is mixed with a solvent to obtain the second component.

[0118] Illustratively, the preparation of the second component includes: adjusting the water content of the solvent under nitrogen protection, adding an isocyanate curing agent, and stirring uniformly to obtain the second component.

[0119] According to another specific embodiment of the present invention, there is provided use of the highly weather-resistant water-based coating as described above in coating a glass fiber reinforced composite material structure.

[0120] In some examples, the substrate of the glass fiber reinforced composite material structure is not pre-treated before coating. The pre-treatment herein includes but is not limited to grinding, burning, sandblasting, etc.

[0121] In some examples, the structure is a photovoltaic frame.

[0122] According to another specific embodiment of the present invention, a glass fiber reinforced composite material structure is provided. The structure comprises a substrate and a coating formed by the above-mentioned highly weather-resistant water-based coating applied on the surface of the substrate.

[0123] Exemplarily, the substrate refers to a base formed by a glass fiber reinforced composite material without coating.

[0124] Exemplarily, the structure is a photovoltaic frame.

[0125] According to another embodiment of the present invention, there is provided a method for preparing the glass fiber reinforced composite material structure as described above, comprising the following steps:

[0126] The highly weather-resistant water-based coating is applied on a substrate to form a coating, wherein the substrate is not pre-treated before coating.

[0127] The substrate is a base formed by a glass fiber reinforced composite material without coating.

[0128] Exemplarily, the structure is a photovoltaic frame.

[0129] It should be noted that in this embodiment, the highly weather-resistant water-based coating can be used to coat both untreated and pre-treated substrates. After coating the pre-treated substrate, the coated structure also has good adhesion and outdoor weather resistance in extreme environments, which will not be described in detail here.

[0130] In some specific examples, the method for preparing the glass fiber reinforced composite material structure includes the following steps:

[0131] Under the environmental conditions of 25±2°C and relative humidity of 50±5%, the first component and the second component of the highly weather-resistant water-based coating are mixed evenly in the corresponding proportions, and then deionized water is added to adjust the construction viscosity to 4 cups. The viscosity is within 30-40 seconds, and spray 3-4 times;

[0132] The substrate refers to a base formed by a glass fiber reinforced composite material that is not coated with paint, and the substrate does not need to be pre-treated before coating.

[0133] In some examples, in the preparation method, the dry film thickness of the coating obtained by coating is 30-40 μm.

[0134] The technical solution of the present invention is described below with reference to some specific embodiments:

[0135] Unless otherwise stated, the silane hydrolyzed oligomers used in the examples were prepared by the following method:

[0136] First, add 40 parts of methyltriethoxysilane, 5 parts of tetraethyl silicate, 10 parts of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 15 parts of anhydrous ethanol, and 5 parts of ethylene glycol butyl ether into a three-necked flask and premix them at a speed of 400-700 rpm; then take 15 parts of aqueous silica sol ST-O-40 and 1 part of acid catalyst dilute hydrochloric acid (concentration of 0.1 mol / L) into a dropping funnel, and add them dropwise after the temperature of the premixed liquid rises to 80°C. The aqueous silica sol and the acid catalyst are controlled to be added dropwise within 0.5h and 1h, respectively. Finally, the resulting mixture is kept warm and reacted for 1h, then subjected to rotary evaporation at 40°C to remove small molecular by-products. The silane hydrolysis oligomer is obtained by aging overnight.

[0137] Example 1

[0138] A highly weather-resistant water-based coating for glass fiber composite materials without pre-treatment, which is a two-component coating, wherein:

[0139] The raw material composition of component A is shown in Table 1 below;

[0140] The B component formula is: 70 parts of Bayhydur Ultra 2655 and 30 parts of propylene glycol diacetate.

[0141] The preparation method of the above-mentioned high-weather-resistant water-based coating for glass fiber composite materials without pre-treatment comprises the following steps:

[0142] Preparation of component A:

[0143] After adding water-based acrylic resin to the organic solvent, stir at medium speed for 10-15 minutes, then add additives (substrate wetting agent, leveling agent, defoamer, rheological additive, UV absorber, UV stabilizer), filler, and nano-color paste and disperse and mix evenly at high speed. Finally, adjust the viscosity to 100-5000mPas with deionized water, filter, and obtain component A.

[0144] Preparation of component B:

[0145] Under nitrogen protection, the water content of the solvent propylene glycol diacetate was adjusted, and the isocyanate curing agent Bayhydur Ultra 2655 was added and stirred evenly to obtain component B.

[0146] Wherein, component A and component B are mixed at a mass ratio of 100:40 when used to obtain an aqueous coating composition 1.

[0147] Example 2

[0148] A highly weather-resistant water-based coating for glass fiber composite materials without pre-treatment, which is a two-component coating, wherein:

[0149] The raw material composition of component A is shown in Table 1 below;

[0150] The B component formula is: 70 parts of Bayhydur Ultra 2655 and 30 parts of propylene glycol diacetate.

[0151] The preparation method of the above-mentioned high-weather-resistant water-based coating for glass fiber composite materials without pre-treatment comprises the following steps:

[0152] Preparation of component A:

[0153] After adding water-based acrylic resin and silane hydrolyzed oligomer to the organic solvent, stir at medium speed for 10-15 minutes, then add additives (substrate wetting agent, leveling agent, defoamer, rheological additive, UV absorber, UV stabilizer), filler, and nano-color paste and disperse and mix at high speed. Finally, adjust the viscosity to 100-5000mPas with deionized water, filter, and obtain component A.

[0154] Preparation of component B:

[0155] Under nitrogen protection, the water content of the solvent propylene glycol diacetate was adjusted, and the isocyanate curing agent Bayhydur Ultra 2655 was added and stirred evenly to obtain component B.

[0156] Component A and component B are mixed at a mass ratio of 100:40 when used to obtain an aqueous coating composition 2.

[0157] Table 1A component formula

[0158]

[0159] Table 2A component formula

[0160]

[0161] Example 3

[0162] Example 2 was repeated, except that, in the formula of component A in this embodiment, the water-based acrylic resin was a mixture of a water-based hydroxy acrylic dispersion and an organic fluorine-modified water-based acrylic resin in a mass ratio of 7:3, and other conditions remained unchanged to prepare a water-based coating composition 3.

[0163] Example 4

[0164] Example 3 was repeated, except that in the formulation of component A, the silane hydrolyzed oligomer was the commercially available product KR-513, and other conditions remained unchanged to prepare an aqueous coating composition 4.

[0165] Example 5

[0166] Example 3 was repeated, except that in the formulation of component A in this example, the silane hydrolyzed oligomer was the commercially available product X-41-1805, and other conditions remained unchanged to prepare an aqueous coating composition 5.

[0167] Example 6

[0168] Example 3 was repeated, except that, in the formulation of component A, the mass ratio of the aqueous hydroxylated acrylic dispersion to the organic fluorine-modified aqueous acrylic resin was 3:7, and the other conditions remained unchanged to prepare an aqueous coating composition 6.

[0169] Example 7

[0170] Example 3 was repeated, except that, in the formulation of component A, the filler did not contain barium sulfate. Other conditions remained unchanged, and an aqueous coating composition 7 was prepared.

[0171] Example 8

[0172] Example 3 was repeated, except that, in the formulation of component A, the filler did not contain mica powder. Other conditions remained unchanged, and an aqueous coating composition 8 was prepared.

[0173] Example 9

[0174] Example 3 was repeated, except that, in this example, the filler in the formula of component A contained only 2000-mesh mica powder, and its content in component A was 7 wt %. Other conditions remained unchanged, and an aqueous coating composition 9 was prepared.

[0175] Example 10

[0176] Example 3 was repeated, except that, in this example, the filler in the formula of component A contained only 2000 mesh barium sulfate, and its content in component A was 9 wt %. Other conditions remained unchanged, and an aqueous coating composition 10 was prepared.

[0177] The coatings obtained in the above embodiments were applied to the glass fiber composite substrate (without pretreatment) in the same construction method, and the performance of the coatings finally obtained was tested. The test results are shown in Tables 3 and 4 below.

[0178] The specific coating method includes the following steps:

[0179] Under the environmental conditions of 25±2℃ and relative humidity of 50±5%, mix component A and component B in the corresponding proportions, then add deionized water to adjust the construction viscosity to 4 cups. Use Iwata W-101 spray gun to spray 3-4 times within 30-40 seconds.

[0180] Table 3. Performance test results of coating

[0181]

[0182] Table 4. Performance test results of coating

[0183]

[0184] The results in Tables 3 and 4 show that the highly weather-resistant water-based coating of the present invention can well wet and level the surface of the glass fiber composite substrate (without pretreatment) and provide excellent adhesion and decorative properties. At the same time, the highly weather-resistant water-based coating has good mechanical properties and aging resistance, which meets the application requirements of the glass fiber composite substrate in various harsh environments.

[0185] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A highly weather-resistant water-based coating for glass fiber composite materials without pre-treatment, characterized in that: The highly weather-resistant water-based coating is a two-component coating, wherein: The raw materials of the first component include, by weight: 30-80 parts of water-based acrylic resin, 5-20 parts of silane hydrolyzed oligomer, 2-10 parts of organic solvent, 2.1-30 parts of additives, 5-25 parts of filler, 5-15 parts of nano color paste and 5-25 parts of deionized water; The raw materials of the second component include, by weight: 70-90 parts of isocyanate curing agent and 10-30 parts of solvent; The water-based acrylic resin is a mixture of a water-based hydroxyl acrylic resin and an organic fluorine-modified water-based acrylic resin in a mass ratio of (0.4-5):1; The silane hydrolysis oligomer is an oligomer obtained by reacting an organic functional silane monomer and silica sol in the presence of an acid catalyst and an organic solvent using a sol-gel method; The filler is a mixture of spherical fillers and flake fillers in a mass ratio of 1:1-10:1; The spherical filler is selected from one or more of barium sulfate, calcium carbonate, quartz powder and fumed silica; The particle size of the spherical filler is 350 mesh to 2500 mesh; The flaky filler is selected from one or more of kaolin, talc, mica, graphite powder, bentonite and attapulgite; The particle size of the flaky filler is 325 meshes to 2500 meshes.

2. The high weather-resistant water-based coating for glass fiber composite materials without pre-treatment according to claim 1, characterized in that: The reaction temperature is 40-80° C. and the reaction time is 1-3 h.

3. The high weather-resistant water-based coating for glass fiber composite materials without pre-treatment according to claim 1, characterized in that: In the method for preparing the silane hydrolyzed oligomer by the sol-gel method, the amount of the organic functional silane monomer is 20-60 parts, the amount of silica sol is 5-15 parts, the amount of acid catalyst is 1-5 parts, and the amount of organic solvent is 10-20 parts.

4. The high weather-resistant water-based coating for glass fiber composite materials without pre-treatment according to claim 1 or 3, characterized in that: The preparation of the silane hydrolysis oligomer comprises the following steps: Premixing the organofunctional silane monomer and the organic solvent at a rotation speed of 400-700 rpm to obtain a premixed solution; After the temperature of the premixed liquid is raised to 80° C., silica sol and acid catalyst are added dropwise respectively, and the addition of silica sol and acid catalyst is controlled to be completed within 0.5 h and 1 h, respectively. Finally, the obtained mixture is kept warm and reacted for 1 h, and then subjected to rotary evaporation at 40° C. to remove small molecular by-products and mature to obtain the silane hydrolysis oligomer.

5. The high weather-resistant water-based coating for glass fiber composite materials without pre-treatment according to claim 1, characterized in that: The mass ratio of the water-based acrylic resin to the filler is (2-8):

1.

6. The high weather-resistant water-based coating for glass fiber composite materials without pre-treatment according to claim 1, characterized in that: The auxiliary agent comprises 1-10 parts of ultraviolet light absorber and 1-10 parts of ultraviolet light stabilizer.

7. The method for preparing a high-weather-resistant water-based coating for glass fiber composite materials without pre-treatment according to any one of claims 1 to 6, characterized in that: The steps include: Preparation of the first component: Dissolving the water-based acrylic resin and silane hydrolyzed oligomer in an organic solvent, mixing them evenly, then adding an additive, a filler, and a nano-color paste, mixing them evenly, and adjusting the viscosity with deionized water to obtain the first component; Preparation of the second component: The isocyanate curing agent is mixed with a solvent to obtain the second component.

8. Use of the highly weather-resistant water-based coating for glass fiber composite materials without pre-treatment according to any one of claims 1 to 6 in coating glass fiber reinforced composite materials, characterized in that: The substrate of the glass fiber reinforced composite material structure is not pre-treated before coating.

9. Use of the highly weather-resistant water-based coating for glass fiber composite materials without pre-treatment according to claim 8 in coating of glass fiber reinforced composite materials structure, characterized in that: The structure is a photovoltaic frame.

10. A glass fiber reinforced composite material structure, characterized in that: The invention comprises a substrate and a coating formed by the high weather-resistant water-based coating for pre-treatment-free glass fiber composite materials according to any one of claims 1 to 6, which is coated on the surface of the substrate.

11. The glass fiber reinforced composite material structure according to claim 10, characterized in that: The structure is a photovoltaic frame.

12. The method for preparing a glass fiber reinforced composite material structure according to claim 10 or 11, wherein: The steps include: The highly weather-resistant water-based coating is applied on a substrate to form a coating, wherein the substrate is not pre-treated before coating.

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