Low temperature curable anti-reflective compositions and coatings formed therefrom

Abstract

The invention provides an anti-reflection composition capable of being cured at low temperature and a coating formed by the anti-reflection composition. The anti-reflection coating is formed by the anti-reflection composition. The anti-reflection composition capable of being cured at low temperature comprises (A) a silicon dioxide sol-gel component; (B) photocatalyst particles; (C) a siloxane oligomer; and (D) a basic catalyst selected from the group consisting of amino silanes, organic amine compounds, and combinations thereof, in which the amount of the basic catalyst is less than about 0.1 parts by weight based on 100 parts by weight of the solid content of the anti-reflective composition.

Description

Technical Field

[0001] The present invention relates to a low-temperature curable anti-reflection composition and a coating formed therefrom, and particularly to an anti-reflection composition that can be cured at room temperature and has self-cleaning and easy-cleaning characteristics, and a coating formed therefrom. Background Art

[0002] Due to energy shortages, the industry has been continuously seeking various energy alternative solutions, among which solar power generation has become increasingly popular. However, the surface of solar panels is prone to contamination by dirt such as air pollutants, dust, bird or poultry excrement. As the usage time increases, when the dirt accumulates continuously, it will cover the surface of the solar panel, resulting in a reduction in its anti-reflection and light-transmitting effects, thereby reducing its power generation and efficiency.

[0003] Currently, it is usually in the way of manual cleaning, scrubbing the dirt to maintain the normal operation and power generation effect of the solar panel. The frequency of manual cleaning affects the annual maintenance cost. The prior art has developed a coating applied to solar panels, and a photocatalyst is added to the coating. Utilizing the hydrophilicity of the photocatalyst and the characteristics of decomposing organic pollutants, the maintenance frequency and cost of annual manual cleaning are reduced. However, after this coating is applied to the solar panel, it needs to be heat-treated at a high temperature (such as 150 to 700 °C) to be cured. In addition to increasing the process cost, due to its process limitations, it is difficult to be applied to installed or in-use solar panels. Summary of the Invention

[0004] In view of this, the present invention provides a low-temperature curable anti-reflection composition. The anti-reflection composition of the present invention can be cured on a panel or a substrate at a low temperature (for example, a temperature below 100 °C), or even at room temperature. Therefore, it can be coated on-site on installed solar panels or in-use solar panels, reduce or repair panel scratches, extend the service life of the solar panel and optimize its power generation efficiency. The anti-reflection composition of the present invention has both easy-cleaning and self-cleaning effects, can effectively reduce the attachment of pollution, improve the light transmittance and average power generation, and can further simplify the manual cleaning process.

[0005] Specifically, an embodiment of the present invention provides a low-temperature curable anti-reflection composition, which comprises:

[0006] (A) A silica sol-gel component;

[0007] (B) Photocatalyst particles;

[0008] (C) A siloxane oligomer; and

[0009] (D) A basic catalyst selected from amino silanes, organic amine compounds, and combinations thereof, wherein based on 100 parts by weight of the solid content of the antireflection composition, the amount of the basic catalyst used is less than about 0.1 part by weight.

[0010] Another embodiment of the present invention provides an antireflection coating formed from the aforementioned antireflection composition. Detailed embodiments

[0011] The following will discuss the various embodiments of the present invention in more detail. However, this embodiment can be an application of various inventive concepts and can be specifically implemented within various different specific ranges. The specific embodiments are for illustrative purposes only and are not limited to the disclosed scope.

[0012] In the following paragraphs, different embodiments of the present invention are more specifically defined. Unless otherwise clearly indicated to the contrary, each embodiment so defined can be combined with any other embodiment. Specifically, any feature indicated as being preferred or advantageous can be combined with any one or more other features indicated as being preferred or advantageous.

[0013] For ease of understanding the disclosure presented herein, several terms are defined below. The terms used herein are for the purpose of describing specific embodiments only and are not intended to be limiting of the present invention. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Further, it is understood that when the terms "comprises," "has," or "includes" are used in this specification, they specify the presence of the stated features, numbers, steps, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0014] All numbers expressing contents, ratios, physical characteristics, etc. used in this specification and claims should be understood to be modified in all cases by the term "about." As used herein, the term "about" means an acceptable error of a specific value as determined by a person skilled in the art, which depends in part on how the value is measured or determined.

[0015] The ranges disclosed herein should be understood to cover any and all sub-ranges subsumed therein, unless otherwise indicated. For example, the range "1 to 10" should be considered to include any and all sub-ranges between the minimum value 1 and the maximum value 10 and including the minimum value 1 and the maximum value 10; that is, all sub-ranges starting with a minimum value of 1 or greater than 1 and ending with a maximum value of 10 or less than 10, such as: 1 to 6.7, 3.2 to 8.1, or 5.5 to 10, and any digit within the range, such as: 2.6, 4.7, or 7.3.

[0016] As used herein, the term "alkyl" refers to a saturated straight-chain or branched-chain hydrocarbon group, preferably having 1 to 6 carbon atoms, more preferably having 1 to 4 carbon atoms, and most preferably having 1 to 3 carbon atoms; examples thereof include (but are not limited to): methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, and the like.

[0017] As used herein, the term "alkylene" refers to a divalent group derived by further extracting a hydrogen atom from a respective monovalent group. For example, alkylene is derived from alkyl.

[0018] As used herein, the term "alkoxy" refers to -O-alkyl. Examples include methoxy, ethoxy, propoxy, isopropoxy, and similar groups.

[0019] In the present invention, "particle size" refers to the average particle size (arithmetic average particle size) of the particles, which can be measured by, for example, measuring the particle size distribution with a particle size analyzer and obtaining its average value.

[0020] The antireflection composition of the present invention contains the aforementioned components (A) to (D), and the following describes each component.

[0021] (A) Silica sol-gel component

[0022] In some embodiments, the silica sol-gel component contains a siloxane monomer and silica particles. In some embodiments, the siloxane monomer used in the present invention can be, for example but not limited to, trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, tetraethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane.

[0023] In some embodiments, when the solid content of the antireflection composition is 100 parts by weight, the solid content of the silica sol-gel component can be between about 70 parts by weight and about 99 parts by weight, preferably between about 80 parts by weight and about 98 parts by weight. In some examples, the amount of the silica sol-gel component can be, for example: about 70 parts by weight, about 75 parts by weight, about 80 parts by weight, about 82 parts by weight, about 84 parts by weight, about 86 parts by weight, about 88 parts by weight, about 90 parts by weight, about 92 parts by weight, about 95 parts by weight, about 97 parts by weight, about 99 parts by weight.

[0024] Compared with some existing technologies applied to high-temperature curing systems, since the silica sol-gel component of the present invention can have a relatively high content of silica (i.e., a relatively high weight ratio of silica and siloxane monomers), the present invention can be used in low-temperature or room-temperature curing systems. In low-temperature or room-temperature curing systems, siloxane monomers mainly act as resin binders. Therefore, under the condition of using a relatively high content of SiO2, more fine pores can still be stacked, and the coating can have a relatively high light transmittance. However, if the weight ratio of silica and siloxane monomers is too high, the formed antireflection coating is relatively hard and brittle, and it is even difficult to form a film. If the weight ratio is too small, the amount of silica used is small, and the number of pores that can be stacked is also small, and the transmittance of the formed antireflection coating is not good.

[0025] In some embodiments, in addition to adjusting the formula to lower the overall condensation temperature to achieve low-temperature or room-temperature curing, the present invention can also use more SiO2 in this system to further enhance the light transmission effect. In some embodiments, the weight ratio of silica and siloxane monomers in the silica sol-gel component ranges from about 3:1 to about 0.5:1, preferably ranges from about 2:1 to about 0.6:1, and more preferably ranges from about 1.2:1 to about 0.7:1. In one embodiment, the weight ratio of silica and siloxane monomers can be, for example: about 3:1, about 2.8:1, about 2.6:1, about 2.4:1, about 2.2:1, about 2:1, about 1.8:1, about 1.6:1, about 1.4:1, about 1.2:1, about 1.1:1, about 1:1, about 0.8:1, about 0.6:1, about 0.5:1.

[0026] In some embodiments, the particle size of the silica particles in the silica sol-gel component ranges from about 5 nm to about 100 nm, preferably ranges from about 10 nm to about 50 nm, and more preferably ranges from about 15 nm to about 30 nm. In one embodiment, the particle size of the silica particles can be, for example: about 5 nm, about 8 nm, about 10 nm, about 12 nm, about 15 nm, about 20 nm, about 25 nm, about 30 nm, about 35 nm, about 40 nm, about 50 nm, about 60 nm, about 70 nm, about 80 nm, about 90 nm, about 100 nm.

[0027] The silica sol-gel component of the present invention can be prepared by mixing a siloxane monomer, silica particles, a solvent and water, stirring, and then subjecting to heat treatment (for example, a temperature between about 70°C and about 90°C). There is no particular limitation on the addition order of each component, that is, each component can be mixed with the siloxane monomer all at once or in any order. In some embodiments, the above heat treatment is preferably carried out in an acidic environment. For example, an appropriate organic acid (such as but not limited to acetic acid or citric acid) or inorganic acid (such as but not limited to hydrochloric acid, nitric acid) can be added to the reactants. In one embodiment, the above heat treatment is carried out in an acidic environment with a pH value between about 3 and 4 (for example, 3, 3.2, 3.4, 3.6, 3.8, 4). In one embodiment, the silica sol-gel component is heat-treated to present a sol state, and then undergoes a condensation reaction and cures into a film after being blended with the remaining components in a subsequent process.

[0028] The solvent used for preparing the silica sol-gel component is not particularly limited in principle, and can be a suitable solvent known to those skilled in the art, such as but not limited to water, alcohols, ethers, esters, ketones or combinations thereof. Non-limiting examples of alcohol solvents include methanol, ethanol, propanol, isopropanol, propylene glycol, butanol, isobutanol or other similar substances. Non-limiting examples of ether solvents can include propyl ether, butyl ether, ethylene glycol methyl ether, ethylene glycol monobutyl ether, propylene glycol methyl ether, ethylene glycol methyl ether acetate, propylene glycol methyl ether acetate, diethylene glycol butyl ether acetate (diethylene glycol butyl ether acetate) or other similar substances. Non-limiting examples of ester solvents include ethyl acetate, butyl acetate, diethyl carbonate, ethyl formate, methyl acetate, ethoxyethyl acetate, ethoxypropyl acetate or monomethyl ether propylene glycol ester or other similar substances. Non-limiting examples of ketone solvents include acetone, methyl ethyl ketone or methyl isobutyl ketone or other similar substances.

[0029] (B) Photocatalyst particles

[0030] In some embodiments, the photocatalyst particles used in the present invention can be nano-photocatalyst particles. The photocatalyst particles used in the present invention can be, but are not limited to: titanium dioxide, cadmium oxide, zinc oxide, tin dioxide, chromium dioxide, cadmium sulfide or zinc sulfide, preferably titanium dioxide. The photocatalyst particles used in the present invention can be photocatalyst particles applicable to visible light, ultraviolet light, or both, but are not limited thereto. In some embodiments, the present invention uses titanium dioxide particles applicable to visible light or titanium dioxide particles applicable to both visible light and ultraviolet light.

[0031] The present invention can endow the prepared coating with the efficacy of easy cleaning and / or self-cleaning by adding photocatalyst particles. For example, in some embodiments, titanium dioxide photocatalyst particles are used. On the one hand, through the photocatalytic action generated by titanium dioxide after illumination, organic pollutants can be decomposed to achieve the self-cleaning effect. On the other hand, through the hydrophilic phenomenon generated by titanium dioxide after illumination, the surface dirt of the coating formed by the composition can be removed to achieve the easy-cleaning effect.

[0032] In some embodiments, when the solid content of the antireflection composition is 100 parts by weight, the dosage of the photocatalyst particles ranges from about 1 part by weight to about 20 parts by weight. In some examples, the dosage of the photocatalyst particles can be, for example: about 1 part by weight, about 2 parts by weight, about 4 parts by weight, about 6 parts by weight, about 8 parts by weight, about 10 parts by weight, about 15 parts by weight, about 20 parts by weight.

[0033] In some embodiments, the ratio of the weight of silica to the photocatalyst particles ranges from about 1 to about 30, preferably from about 2 to about 25, more preferably from about 3 to about 20, for example: about 1, about 2, about 3, about 5, about 6, about 7, about 8, about 10, about 12, about 14, about 15, about 16, about 17, about 18, about 19, about 22, about 23, about 25, about 30; if the weight ratio of the silica sol-gel component to the photocatalyst particles is too large, the self-cleaning effect of the formed antireflection coating is poor, and if the weight ratio is too small, the transmittance of the formed antireflection coating is poor.

[0034] In some embodiments, the photocatalyst particles used in the present invention can be nano-photocatalyst particles. In some embodiments, the particle size of the photocatalyst particles used in the present invention is less than about 100 nm, preferably 5 - 40 nm, more preferably 10 nm - 30 nm. In some embodiments, the particle size of the photocatalyst particles used in the present invention can be, for example, about 5 nm, about 10 nm, about 15 nm, about 20 nm, about 30 nm, about 40 nm, about 45 nm, about 50 nm, about 55 nm, about 60 nm, about 70 nm, about 80 nm, about 90 nm, about 100 nm.

[0035] (C) Siloxane oligomer

[0036] The antireflection composition of the present invention contains a siloxane oligomer, whereby the dispersibility of the photocatalyst particles (such as titanium dioxide) can be increased. In one embodiment, the siloxane oligomer used in the present invention has a structure as shown in formula (II):

[0037]

[0038] Wherein each R 3 can be the same or different, and each R 3 independently represents a methyl group or a phenyl group; each R4 may be the same or different, and each R 4 independently represents H, methyl or ethyl, preferably methyl; and m is an integer between 2 and 20, preferably an integer between 5 and 12.

[0039] In some embodiments, the molecular weight of the siloxane oligomer used in the present invention is between about 500 g / mol and about 3,000 g / mol, preferably between about 800 g / mol and about 2,000 g / mol, more preferably between about 1,000 g / mol and about 1,600 g / mol. In one example, the molecular weight of the siloxane oligomer can be, for example: about 500 g / mol, about 800 g / mol, about 1,000 g / mol, about 1,200 g / mol, about 1,400 g / mol, about 1,500 g / mol, about 1,800 g / mol, about 2,000 g / mol, about 2,500 g / mol, about 3,000 g / mol.

[0040] In some embodiments, when the solid content of the antireflection composition is 100 parts by weight, the amount of the siloxane oligomer used is between about 1 part by weight and about 20 parts by weight. In some examples, the amount of the photocatalyst particles used can be, for example: about 1 part by weight, about 2 parts by weight, about 4 parts by weight, about 6 parts by weight, about 8 parts by weight, about 10 parts by weight, about 15 parts by weight, about 20 parts by weight.

[0041] (D) Basic catalyst

[0042] In some embodiments, the basic catalyst used in the present invention is selected from aminosilanes, organic amine compounds, and combinations thereof.

[0043] In some embodiments, the aminosilane used in the present invention has the formula (III):

[0044] (R 5 )(R 6 ) p Si(OR 7 ) 3-p Formula (III)

[0045] Wherein, each R 6 may be the same or different, and each R 6 independently represents C 1-4 alkyl; each R 7 may be the same or different, and each R 7 independently represents C 1-3 alkyl; R 5 is -(C 1-4 alkylene)-NHR 8 ; R 8 is H, phenyl or C 1-4Alkyl, the C 1-4 The alkyl may be optionally substituted by the following groups: amino group, C 1-4 alkylamino group or -(R 6 ) p Si(OR 7 ) 3-p ; and p is 0, 1 or 2.

[0046] In some preferred embodiments, each R 6 may be the same or different, and each R 6 independently represents methyl or ethyl; each R 7 may be the same or different, and each R 7 is independently methyl or ethyl; R 5 is 3-aminopropyl, γ-divinyltriaminopropyl, N-(2-aminoethyl)-3-aminopropyl, or -(C 1-4 alkylene)-NH-(C 1-4 alkylene)-(R 6 ) p Si(OR 7 ) 3-p ; and p is 0 or 1.

[0047] In some embodiments, the aminosilane used in the present invention may be, for example but not limited to: 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, Y-divinyltriaminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(3-trimethoxysilylpropyl)amine or anilinomethyltriethoxysilane. In some embodiments, the aminosilane is preferably 3-aminopropyltrimethoxysilane.

[0048] The organic amine compound used in the present invention may be a primary amine, a secondary amine or a tertiary amine. In some embodiments, the organic amine compound used in the present invention may have the formula (IV) or formula (V):

[0049] N(R a )(R b )(R c ) Formula (IV)

[0050] (NH2)-R d -(OH) Formula (V)

[0051] Wherein, R a , R b and R c may be the same or different, and are each independently H, C 1-4 alkyl or C 1-4 alkanol group, with the limitation that R a , Rb and R c are not simultaneously H; R d is C 1-6 alkylene group.

[0052] In some preferred embodiments, R a , R b and R c may be the same or different and are each independently methyl, ethyl, propyl, methanol group, ethanol group or propanol group; R d is methyl, ethyl, propyl, n-butylene.

[0053] In some embodiments, the organic amine compound used in the present invention may be, for example but not limited to: 2-amino-2-methyl-1-propanol, triethylamine or triethanolamine.

[0054] Generally speaking, the sol-gel reaction is faster in an alkaline environment, which promotes the condensation reaction. However, if the condensation rate is too fast, it will cause it to aggregate into clusters, resulting in an increase in the haze of the resulting coating and a decrease in light transmittance. The inventors of this case found that by adding the specific alkaline catalyst of the present invention (such as the aforementioned selected from amino silanes, organic amine compounds and combinations thereof), the condensation reaction can be promoted while avoiding the aforementioned aggregation phenomenon. When the antireflection composition is applied or coated on the surface of a substrate, it can form a film by curing at a low temperature (for example, below 100 °C), or even at room temperature (for example, 20 °C to 25 °C), and the aforementioned aggregation phenomenon can be avoided. In addition, in some embodiments, the substrates referred to herein include, but are not limited to, solar panels, solar modules, antireflection panels, light-absorbing panels or combinations thereof, or any panel or module or combination thereof for absorbing light, infrared light, ultraviolet light.

[0055] The inventors of the present case further found that adjusting the amount of the basic catalyst can endow the resulting coating with improved properties such as alcohol resistance, adhesion, hardness, light transmittance, etc. In some embodiments, when the solid content of the antireflection composition is 100 parts by weight, the amount of the basic catalyst is less than about 0.1 part by weight. In some examples, when the solid content of the antireflection composition is 100 parts by weight, the amount of the basic catalyst ranges from about 0.001 part by weight to about 0.1 part by weight. In some examples, the amount of the basic catalyst can be, for example: about 0.001 part by weight, about 0.002 part by weight, about 0.003 part by weight, about 0.004 part by weight, about 0.005 part by weight, about 0.008 part by weight, about 0.009 part by weight, about 0.01 part by weight, about 0.03 part by weight, about 0.05 part by weight, about 0.08 part by weight, about 0.09 part by weight, about 0.1 part by weight. Specifically, the inventors of the present case found that when the amount of the basic catalyst is too low, the condensation reaction of the composition is very slow, and the resulting coating has poor alcohol resistance, adhesion and hardness. Higher temperature is required to accelerate the condensation reaction, and the purpose of low-temperature or room-temperature curing cannot be achieved; when the amount of the basic catalyst is too high, the condensation rate of the composition is too fast, and a uniform film cannot be formed. The resulting coating has poor light transmittance, poor alcohol resistance and adhesion, and the coating film is brittle.

[0056] The composition of the present invention can achieve low-temperature or room-temperature curing. In some examples, the curing temperature of the composition of the present invention after being applied to a substrate can range from about 15 °C to about 100 °C, preferably from about 20 °C to about 60 °C. In some examples, the curing temperature of the composition of the present invention can be, for example: about 15 °C, about 20 °C, about 25 °C, about 30 °C, about 35 °C, about 40 °C, about 45 °C, about 50 °C, about 55 °C, about 60 °C, about 65 °C, about 70 °C, about 80 °C, about 90 °C, about 100 °C.

[0057] (E) Solvent

[0058] In some embodiments, the antireflection composition of the present invention further comprises a solvent. In some examples, the solvent used in the present invention can be alcohols, water, ethers, esters, ketones or combinations thereof. Non-limiting examples of alcohol solvents, ether solvents, ester solvents, and ketone solvents are as previously described herein. In some preferred embodiments, the solvent used in the present invention comprises water, methanol, ethanol, acetone, isopropanol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol methyl ether acetate, propylene glycol monomethyl ether, butanol or combinations thereof.

[0059] In some preferred embodiments, the anti-reflection composition of the present invention comprises a first solvent and a second solvent. Specifically, the first solvent is a high-boiling solvent and the second solvent is a low-boiling solvent. In some embodiments, the first solvent has a boiling point above about 100 °C, such as above about 105 °C, above about 110 °C, above about 115 °C; the second solvent has a boiling point below about 100 °C, such as below about 95 °C, below about 90 °C, below about 85 °C.

[0060] In some embodiments, the boiling point of the first solvent is preferably below about 180 °C, such as below about 170 °C, below about 160 °C, below about 150 °C; the boiling point of the second solvent is preferably above about 30 °C, such as above about 40 °C, above about 50 °C.

[0061] In some embodiments, the boiling point of the first solvent can be, for example: about 100 °C, about 110 °C, about 120 °C, about 130 °C, about 140 °C, about 150 °C, about 160 °C, about 170 °C, about 180 °C. In some embodiments, the boiling point of the second solvent can be, for example: about 95 °C, about 90 °C, about 85 °C, about 80 °C, about 75 °C, about 70 °C, about 65 °C, about 60 °C, about 55 °C, about 50 °C, about 40 °C, about 30 °C.

[0062] In some embodiments, the first solvent comprises water, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol methyl ether acetate, propylene glycol monomethyl ether or butanol, and the second solvent comprises methanol, ethanol, acetone or isopropanol.

[0063] In some embodiments, the amount of the first solvent is greater than or equal to the amount of the second solvent. In some embodiments, the weight ratio of the amounts of the first solvent and the second solvent is between about 10:1 and about 1:1, such as: about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1. In some embodiments, the weight ratio of the amounts of the first solvent and the second solvent can be, for example, about 5:1 to 2:1. If the weight ratio of the amounts of the first solvent and the second solvent is high, the curing rate of the formed coating is slow and the initial physical properties do not meet the requirements. If the weight ratio of the amounts of the first solvent and the second solvent is low, the curing rate of the formed coating is too fast and it is impossible to form a uniform film, affecting the light transmittance and the physical properties of the coating surface.

[0064] (F) Additives

[0065] The anti-reflection composition of the present invention may optionally contain any additives known to those skilled in the art of the present invention, such as but not limited to colorants, fillers, hardeners, hardener accelerators, ultraviolet absorbers, antistatic agents, matting agents, stabilizers, heat dissipation aids or anti-floating color agents, etc.

[0066] In some embodiments, the antireflection composition of the present invention can be prepared by the following methods, but not limited thereto:

[0067] (a) Provide a silica sol-gel component (A); and

[0068] (b) Mix a photocatalyst particle (B), a siloxane oligomer (C), a basic catalyst (D) selected from aminosilanes, organic amine compounds, and combinations thereof, a solvent, and optional additives, etc. with the silica sol-gel component (A).

[0069] The above step (a) is as described previously herein.

[0070] In the above step (b), after mixing each component, it can be stirred at room temperature. The dispersibility of the siloxane oligomer and the photocatalyst particle added in the composition of the present invention is excellent, which can improve the dispersibility and uniformity of the silica particle and the photocatalyst particle in the composition. There is no special limitation on the addition order and addition time point of each component in the above step (b), that is, these components or solvents can be added and mixed at one time or in any order.

[0071] The antireflection composition of the present invention can be coated on an element or substrate that requires antireflection efficacy to form an enhanced light transmission coating. The composition of the present invention has an easy-to-clean and self-cleaning effect, thereby reducing the accumulated dirt on the coating, and can reduce the frequency and cost of manual cleaning. Furthermore, the composition of the present invention has good fluidity, which is beneficial to the preparation of a thin enhanced light transmission coating, thereby reducing the loss caused by the absorption of light by the resin or other components when the light passes through the enhanced light transmission film layer. Therefore, the composition of the present invention is particularly suitable for the fields of displays or solar cells. While maintaining the surface clean for a long time, it can effectively reduce the light reflection loss and increase the light transmittance, further improving its performance.

[0072] In some embodiments, the substrates used in the present invention include, but are not limited to: glass (such as architectural glass, automotive glass, etc.), solar panels, solar modules, antireflection panels, light-absorbing panels, or combinations thereof, or any panel or module or combination thereof for absorbing light, infrared light, or ultraviolet light.

[0073] In some other embodiments, the present invention can also be applied to light-enhancing and light-penetrating diaphragms. The substrate used can be any transparent substrate known to those skilled in the technical field to which the present invention pertains, such as glass or plastic. There are no special restrictions on the above-mentioned plastic substrate, for example, but not limited to: polyester resin, such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN); polymethacrylate resin, such as polymethylmethacrylate (PMMA); polyimide resin; polystyrene resin; polycycloolefin resin; polyolefin resin; polycarbonate resin; polyurethane resin; triacetate cellulose (TAC); or a mixture thereof. Preferred plastic substrates are polyethylene terephthalate, polymethylmethacrylate, polycycloolefin resin or a mixture thereof, and more preferably polyethylene terephthalate. There are no special restrictions on the thickness of the substrate. If the substrate is glass, it is generally between about 0.1 cm and 0.3 cm; if it is a plastic substrate, it is generally between about 5 μm and about 300 μm.

[0074] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0075] The anti-reflection coating of the present invention has good light transmittance and can be used in any component that needs to increase the total light transmittance, for example, solar cells, building glass curtains or gardening glass, to improve the light utilization rate. According to an embodiment of the present invention, without changing the module design of the solar cell module, the above coating composition can be applied to the solar cell module in any manner well-known to those skilled in the technical field to which the present invention pertains. For example, the anti-reflection composition of the present invention can be directly coated on the elements (such as the front plate or the sealing layer) of the solar cell module to form an anti-reflection coating. When light enters the anti-reflection coating, the light transmittance can be increased, and after being absorbed and utilized by the battery elements, the power generation efficiency can be increased.

[0076] The anti-reflection composition of the present invention can be cured on a panel or substrate at a low temperature (e.g., a temperature below 100 °C), even at room temperature. Therefore, it can be coated on-site on an installed solar panel or a solar panel in use, reducing or repairing panel scratches, extending the service life of the solar panel and optimizing its power generation efficiency. The anti-reflection composition of the present invention has both easy-cleaning and self-cleaning effects, can effectively reduce the attachment of contaminants, improve the light transmittance and average power generation, and can further simplify the manual cleaning process.

[0077] In some embodiments, the anti-reflection composition of the present invention is applied by a one-time single-step coating. In some embodiments, the method of applying the anti-reflection composition can be any well-known to those skilled in the art of the present invention, such as, but not limited to: knife coating, roller coating, micro gravure coating, flow coating, dip coating, spray coating, slot die coating, spin coating, and curtain coating. In one example, the effect of double-sided coating of a glass substrate can be achieved by dip coating and pulling, and the resulting film layer has the advantages of high light transmittance, good adhesion, and good wear resistance.

[0078] In some embodiments, the coating thickness of the anti-reflection composition is between about 50 nm and about 200 nm. In some embodiments, the coating thickness of the anti-reflection composition can be, but not limited to, about 50 nm, about 60 nm, about 70 nm, about 80 nm, about 90 nm, about 100 nm, about 110 nm, about 120 nm, about 130 nm, about 140 nm, about 150 nm, about 160 nm, about 170 nm, about 180 nm, about 190 nm, about 200 nm. Preferably, it is between about 80 nm and about 100 nm.

[0079] The present invention will be further described in detail below with reference to examples, which are not intended to limit the scope of the present invention. Any modifications and changes that can be easily achieved by those skilled in the art are included in the disclosure of this specification and the scope of the appended claims.

[0080] <Preparation Example>

[0081] <Preparation of silica sol-gel component>

[0082] Siloxane monomers, aqueous SiO2 particle solution, acetic acid, solvent and water were premixed and stirred according to the ratios (gram weights) shown in Table 1 below, and nitrogen was introduced and heated to 75 ± 2 °C and held at this temperature for reaction for 6 hours to prepare silica sol-gel components a to d.

[0083] Table 1

[0084]

[0085] Note 1 Total solid content: That is, the proportion of all solids in the composition (weight ratio). For example, take the composition, weigh it, and record its actual weight as a (total weight). After heating to remove the solvent (for example, for 1 gram of the composition, heat it on a hot plate at 60 °C for 30 minutes) and then weigh it again, the measured weight is b (total weight of solids). b / a is the total solid content (%).

[0086] Note 2 SiO2 / total solid content: That is, the ratio of the SiO2 solid content to the total solid content (%). Taking composition a as an example, the solid content weight in the aqueous SiO2 particle solution is 81.85 * 20% = 16.37 grams, the total solid content weight of the composition is 30.35 grams, and the ratio of SiO2 particles / total solid content is 16.37 / 30.35 * 100% = 54%.

[0087] Note 3 Total weight of siloxane monomers / total solid content: That is, the ratio of the siloxane monomer solid content to the total solid content (%). Total weight of siloxane monomers / total solid content + SiO2 / , total solid content = 100%.

[0088] <Preparation of antireflection composition>

[0089] The silica sol-gel components a to e (A), photocatalyst particles (B), siloxane oligomers (C), catalyst (D), and solvent prepared above were added to a bottle according to the ratios (gram weights) shown in Tables 2-1 to 2-3 and stirred evenly to obtain an antireflection composition (where KRONO 7050 is an ultraviolet photocatalyst with an average particle size of 15 nm; 7050 is an ultraviolet / visible light photocatalyst with an average particle size of 15 nm).

[0090]

[0091]

[0092]

[0093] <Preparation of antireflection coating>

[0094] Take about 2.6 g of the antireflection compositions prepared in the above examples and comparative examples, and spin-coat them on a 7.5 cm × 7.5 cm square glass substrate with a light transmittance of 86% under the coating condition of 500 rpm * 50 sec. Then bake the coated specimens at 50 °C for an appropriate time (such as 180 minutes) to prepare a coating with a thickness of about 100 nm (±20 nm).

[0095] <Physical property test>

[0096] Conduct various tests on the antireflection compositions of the above examples and comparative examples. The details of each test are as follows:

[0097] Conduct various tests on the above coatings. The details of each test are as follows:

[0098] Refractive index: Use a prism coupler, and use visible light with a wavelength of 633 nm as the light source for measurement. Measure the refractive index of the sample at 25 °C.

[0099] Light transmittance: Measure with a PerkinElmer Lambda 900. Record the transmittance of the sample at a wavelength of 550 nm (the wavelength most sensitive to human vision) in Table 3.

[0100] Alcohol resistance: Wipe back and forth 150 times on the coating in a wet state with 90% alcohol, and observe whether the coating is damaged or loses its gloss. If the coating is not damaged and does not lose its gloss, it is judged to pass the alcohol resistance test.

[0101] Adhesion: Cross-cut test, that is, on the test panel, cut 11 parallel lines vertically and horizontally, with a spacing of 1 mm between each line. In an area of 1 cm 2 There are 100 squares with an area of 1 mm 2 Or cut into 100 squares with a side length of 1 mm vertically and horizontally 2 Then stick 3M Scotch 600 tape on the squares and quickly peel it off to check the peeling situation. According to the following ASTM D3359 cross-cut tape adhesion test evaluation criteria: 5B means no peeling of the coating; 4B means peeling of less than 5% of the area of the coating; 3B means peeling of 5 - 15% of the area of the coating; 2B means peeling of 15 - 35% of the area of the coating; 1B means peeling of 35 - 65% of the area of the coating; 0B means peeling of more than 65% of the area of the coating.

[0102] Hardness: This is the pencil hardness test method for the coating film. According to ASTM D3363, use a pencil hardness tester and Mitsubishi pencils. Under a load of 1 kg, keep the pencil at a 45° angle to the test surface, and push the instrument to slide by hand, and the pencil will draw a corresponding track on the paint film. Use different pencils to draw different marks, and accordingly, the hardness value of the coating film can be determined.

[0103] Contact angle: The coated layer was irradiated with ultraviolet light (313 nm, illuminance 0.71 W / m 2 ) to measure its contact angle on the 11th day. The contact angle was measured using a contact angle measuring instrument from KRUSS. Water was dropped on the surface of the test piece to measure its dynamic contact angle, and the average value was taken at five points. The dynamic contact angles before and after irradiation were recorded as the "initial water contact angle" and the "water contact angle after irradiation" (i.e., the contact angle on the 11th day), respectively. In addition, Examples 2, 6, and 12 and Comparative Examples 1, 4, and 6 were used as representatives to measure and record the number of days of irradiation required for the water contact angle to reach approximately 10°. The shorter the time, the better the self-cleaning effect. Among them, for Comparative Example 4, since the contact angle had reached ≤10° before the 11th day, it was not necessary to measure the contact angle on the 11th day.

[0104] The results of each test are listed in Table 3-1 and Table 3-1 (continued) below, where the properties such as light transmittance, alcohol resistance, adhesion, and hardness are data with a baking time of 180 minutes.

[0105] Table 3-1

[0106]

[0107] Table 3-1 (continued)

[0108]

[0109] *In the comparative examples, if the alcohol resistance, adhesion, and hardness are not good and do not meet the requirements, the subsequent self-cleaning property evaluation will no longer be carried out, except for the representative comparative examples.

[0110] The light transmittance, adhesion, and hardness of the antireflection coatings of each example and comparative example under different baking times were measured and recorded in Table 3-2 below.

[0111] Table 3-2

[0112]

[0113] Although the present invention has been disclosed above in the form of embodiments and related examples, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the appended claims.

[0114] As can be seen from Table 3-1, the coatings obtained from the antireflection composition of the present invention have better light transmittance, alcohol resistance, adhesion, and hardness, and have self-cleaning effects. The compositions of Examples 10 and 11 are the same as that of Example 2 (the same amount of photocatalyst particles), and only the amount of the basic catalyst is changed to evaluate the influence of the amount of the basic catalyst on the light transmittance, alcohol resistance, adhesion, and hardness. Therefore, the self-cleaning property evaluation is no longer carried out.

[0115] As can be seen from the results of Example 2 and Comparative Examples 3 to 5 in Tables 3-1 and 3-2, Comparative Example 4 does not contain the specific basic catalyst of the present invention. During the resin drying and film-forming process, the condensation reaction proceeds very slowly. Although the light transmittance during film formation increases with the drying time, the alcohol resistance, adhesion, and hardness do not improve after 3 hours of drying because the resin reaction is incomplete. In Comparative Example 5, an inorganic base (sodium hydroxide) was used as the catalyst, and the resin condensation reaction proceeded too fast, resulting in a large amount of silicon particles reacting and aggregating into clusters in the solution, causing the coating to be atomized, the light transmittance to deteriorate, and the film to be unable to form effectively during coating. In Comparative Example 3, too much basic catalyst was used, and the resin condensation reaction proceeded too fast, resulting in a large amount of silicon particles reacting and aggregating into clusters in the solution, causing the coating to be atomized and the light transmittance to deteriorate. In addition, the alcohol resistance and adhesion deteriorated, not meeting the requirements, so the subsequent self-cleaning property evaluation was no longer carried out.

[0116] As can be seen from the results of Comparative Examples 1 and 2 in Table 3-1, the SiO2 / TiO2 ratio in the composition of Comparative Example 1 is too high, resulting in poor self-cleaning effect of the coating; the SiO2 / TiO2 ratio in the composition of Comparative Example 2 is too low, resulting in poor light transmittance, and the alcohol resistance, adhesion, and hardness are also not good, not meeting the requirements, so the subsequent self-cleaning property evaluation was no longer carried out.

[0117] As can be seen from the results of Comparative Examples 6 and 7 in Table 3-1, the weight ratio of the amounts of the first solvent and the second solvent is too low, resulting in too fast curing speed of the formed coating, unable to form a uniform film, the coating unable to pass the alcohol resistance test, and the adhesion and hardness being poor.

Claims

1. A low temperature curable antireflective composition comprising: (A) silica sol-gel component; (B) photocatalyst particles; (C) a siloxane oligomer; and (D) a basic catalyst selected from aminosilane, organic amine compound and a combination thereof, wherein the amount of the basic catalyst is less than 0.1 parts by weight based on 100 parts by weight of the solid content of the anti-reflective composition.

2. The anti-reflective composition according to claim 1, wherein the solid content of the silica sol-gel component is in an amount ranging from 70 parts by weight to 99 parts by weight based on 100 parts by weight of the solid content of the anti-reflective composition.

3. The anti-reflective composition according to claim 1, wherein the silica sol-gel component comprises siloxane monomers and silica particles, wherein the weight ratio of silica to the siloxane monomers in the silica sol-gel component is between 3:1 and 0.5:

1.

4. The antireflective composition according to claim 1, further comprising a first solvent and a second solvent, wherein the first solvent has a boiling point of 110°C or higher, and the second solvent has a boiling point of less than 100°C.

5. The antireflective composition according to claim 1, wherein the aminosilane is selected from the group consisting of the following compounds: 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, γ-diethylenetriaminopropylmethyldimethoxysilane, N-aminoethyl-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, bis(3-trimethoxysilylpropyl)amine, anilinemethyltriethoxysilane and combinations thereof.

6. The antireflective composition according to claim 1, wherein the organic amine compound has a structure selected from the group consisting of formula (IV) and formula (V): N(R a )(R b )(R c ) Formula (IV) (NH2)-R d -(OH) Formula (V) wherein, in, R a , R b and R c may be the same or different and are independently H, C 1-4 Alkyl or C 1-4 Alkyl, with the restriction that R a , R b and R c H; R d C 1-6 Alkylene.

7. The anti-reflective composition according to claim 1, wherein the amount of the alkaline catalyst is between 0.001 parts by weight and 0.1 parts by weight based on 100 parts by weight of the solid content of the anti-reflective composition.

8. The antireflective composition according to claim 1, wherein the photocatalyst particles are selected from the group consisting of titanium dioxide, cadmium oxide, zinc oxide, tin dioxide, chromium dioxide, cadmium sulfide, and zinc sulfide.

9. The antireflective composition according to claim 1, wherein the siloxane oligomer has a structure of formula (II): in, Each R 3 can be the same or different, and each R 3 Each R independently represents a methyl group or a phenyl group; 4 can be the same or different, and each R 4 independently represent H, methyl or ethyl; and m represents an integer between 2 and 20.

10. An antireflection coating formed from the antireflection composition according to any one of claims 1 to 9.

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