Functional melamine resin optical coating cured by sunlight and preparation method of functional melamine resin optical coating

Abstract

The invention discloses a functional melamine resin optical coating cured by sunlight and a preparation method of the functional melamine resin optical coating. The functional melamine resin optical coating is prepared by mixing 100 parts of trifunctional structure melamine resin, 1-10 parts of a cross-linking promoting agent and 1-20 parts of a catalyst. Wherein the melamine resin with the three-functional structure contains three active reactive groups, namely-CH2OH,-CH = CH2 and-O-C (CH2) 2-CO-C6H5, and is prepared from 126 parts of melamine, 243 parts of a formaldehyde solution (37%), 50 to 150 parts of hydroxyethyl acrylate, 50 to 200 parts of polyol and 2 to 10 parts of a photosensitizer through an amination synthesis reaction. According to the functional melamine resin optical coating provided by the invention, the coating curing process has the remarkable characteristics of low carbon, energy conservation, high efficiency and convenience, and the prepared coating has outstanding optical performance and functionality; besides, the functional melamine resin optical coating can be used as a high-performance and functional coating and is widely applied to the field of optical protective coatings.

Description

Technical Field

[0001] The present invention relates to the technical field of functional polymer coatings, and in particular to a functional melamine resin optical coating cured by sunlight and a preparation method thereof, and specifically to a functional melamine resin coating that can be directly used as a coating and cured by sunlight and has excellent light transmittance and coating functionality. Background Art

[0002] Optical coatings are generally required to have basic properties such as high light transmittance and scratch resistance, while also taking into account functionality such as anti-pollution, self-cleaning, corrosion resistance and flame retardancy. They can be widely used in optical devices, electronic displays, automotive glass, solar cells, cultural relics protection, aerospace and other fields.

[0003] Through molecular structure design, polymers can simultaneously meet the high transmittance, hardness and flexibility required by optical coatings. They are expected to become a substitute for traditional inorganic optical coatings, organic optical coatings and organic-inorganic composite optical coatings, and have become one of the research and development hotspots that have attracted much attention. For example, Ji-Eun Jeong et al. prepared a self-repairing protective coating for optical components through the design of a polythiourea dynamic network structure, which has a visible transmittance of 95%, a refractive index of 1.6, and a surface hardness of >200MPa; Kai bo Pan et al. used citric acid and (3-aminopropyl) triethoxysilane as raw materials to prepare a carbonized polymer with a hard core and a soft chain shell as an optical protective coating material, which has a pencil hardness of 9H, can withstand 4000 steel wool abrasion tests, and has excellent bending and rolling flexibility; Minseo Park et al. developed a UV-curable imine-based coating with high thermal stability, excellent surface mechanical properties and optical transparency in the high visible light wavelength region.

[0004] Melamine-formaldehyde resin (melamine resin) is a typical thermosetting amino resin, and its cured product has excellent scratch resistance, adhesion, intrinsic flame retardancy and thermal stability. However, melamine 1000041

[0005] The resin is usually cured by heat curing or acid / heat curing, which is a complicated process with poor operability. In addition, the three-dimensional network structure formed during the curing process makes it difficult to effectively eliminate the stress within the resin molecular chain. Under normal conditions, it is difficult to directly apply it as a general-purpose coating in the actual field of surface coating technology, let alone in the field of functional optical coating technology.

[0006] To this end, the present invention provides a functional melamine resin optical coating that is cured by sunlight and a preparation method thereof. The coating can be cured by sunlight to obtain a coating with excellent light transmittance, while satisfying the coating's high toughness, high strength, self-cleaning and anti-fouling functionality. In addition, the coating curing method has the significant characteristics of being green, low carbon, energy-saving, efficient and convenient, and can be used as a high-performance functional coating and is widely used in the field of optical protective coatings and other surface protective coatings. Summary of the invention

[0007] The present invention provides a functional melamine resin optical coating cured by sunlight and a preparation method thereof. The main purpose is to overcome the technical defects of the existing melamine resin applied to the coating and coating technology fields, such as complicated curing process, long coating film curing cycle and easy cracking of the coating, and to provide a feasible technical solution for the preparation and application of the functional melamine resin optical coating cured by sunlight.

[0008] The present invention provides a functional melamine resin optical coating that uses sunlight for curing and a preparation method thereof, which has achieved good breakthroughs and progress in the curing method of the melamine resin, the optical properties of the coating and the functionality, and has excellent functionality such as high light transmittance, self-cleaning and anti-fouling, and can be used as a high-performance optical protective coating and a functional coating, and is widely used in the field of optical protective coatings and other surface protective coatings.

[0009] According to the first aspect of the present invention, a trifunctional melamine resin is provided. The trifunctional melamine resin is a trifunctional melamine resin containing three active reaction groups (-CH2OH, -CH=CH2 and -OC(CH2)2-CO-C6H5)1000042. Based on this molecular structure, the prepared trifunctional melamine resin can be directly and efficiently cured under sunlight.

[0010] In some optional implementations of some embodiments, the trifunctional melamine resin is prepared from 126 parts of melamine, 243 parts of formaldehyde solution (37%), 50-150 parts of hydroxyethyl acrylate, 50-200 parts of polyol, and 2-10 parts of photosensitizer through an amination reaction process.

[0011] In some optional implementations of some embodiments, the polyol is one or more of ethylene glycol, propylene glycol, glycerol, and polyethylene glycol. Preferably, the polyol is 80 parts of polyethylene glycol 400.

[0012] In some optional implementations of some embodiments, the photosensitizer is one or more of 2-hydroxy-2-methylpropiophenone (UV1173), 4-[4,5-bis[4-(dimethylamino)phenyl]-1H-imidazol-2-yl]-2,6-dimethoxyphenol (UV1) and hydroxycyclohexylphenyl ketone (UV184). Preferably, the photosensitizer is 4 parts of 2-hydroxy-2-methylpropiophenone.

[0013] In some optional implementations of some embodiments, the amination reaction process specifically includes: placing 126 parts of melamine and 243 parts of formaldehyde solution in a three-necked flask, heating to 80°C, waiting for the water tolerance point to appear, cooling to 70°C, adding 50-150 parts of hydroxyethyl acrylate, 50-200 parts of polyol and 2-10 parts of photosensitizer, stirring for 2 hours, and obtaining a trifunctional melamine resin.

[0014] According to a second aspect of the present invention, a functional melamine resin optical coating cured by sunlight is provided, wherein the functional melamine resin optical coating is composed of the following raw materials in parts by weight: 100 parts of trifunctional melamine resin, 1 to 10 parts of crosslinking promoter and 1 to 20 parts of catalyst.

[0015] In some optional implementations of some embodiments, the cross-linking promoter is one or more of propane trimethylol triacrylate (TMPTA) and pentaerythritol triacrylate (PETA). Preferably, the cross-linking promoter is 6 parts of propane trimethylol triacrylate.

[0016] In some optional implementations of some embodiments, the catalyst is one or more of acrylic acid (AA), methacrylic acid (MAA) and maleic acid (MA). Preferably, the catalyst 1000043

[0017] The agent is 12 parts of acrylic acid.

[0018] According to a third aspect of the present invention, there is provided a method for preparing a functional melamine resin optical coating cured by sunlight, comprising: placing 126 parts of melamine and 243 parts of formaldehyde solution in a three-necked flask, heating to 80°C, and cooling to 70°C until a water tolerance point appears, adding 50 to 150 parts of hydroxyethyl acrylate, 50 to 200 parts of polyols and 2 to 10 parts of photosensitizer, and stirring for 2 hours to obtain a trifunctional melamine resin; and mixing the trifunctional melamine resin, a cross-linking promoter and a catalyst according to a ratio to obtain the functional melamine resin optical coating.

[0019] Furthermore, the functional melamine resin optical coating can make full use of the light and heat energy of the sun. After irradiation with sunlight for 5 to 20 minutes, the functional melamine optical coating can be directly and efficiently cured, which completely changes a series of problems such as the curing method of traditional melamine resin, the optical properties of the coating, and the functional properties.

[0020] According to a fourth aspect of the present invention, a method for using a functional melamine resin optical coating that is cured by sunlight is provided. The functional melamine resin optical coating is applied to the surface of an object, and the coating is cured within 5 to 20 minutes under sunlight to obtain a coating. The coating has the following performance indicators: light transmittance ≥98.0%, light refractive index 1.5590, water contact angle ≥100°, water resistance ≥9.0h, impact resistance ≥140mm, pencil hardness ≥5H, abrasion resistance ≤3.2mg / 100 turns, and adhesion ≥7.10MPa.

[0021] The advantages and beneficial effects of the present invention are:

[0022] (1) The functional melamine resin optical coating provided by the present invention uses conventional and readily available raw materials and simultaneously achieves the practical effects of excellent high light transmittance, self-cleaning, anti-fouling and other functionalities.

[0023] (2) The preparation process of the functional melamine resin optical coating provided by the present invention has the characteristics of simple process, green, low carbon, energy saving, high efficiency and convenience.

[0024] (3) The present invention uses a trifunctional melamine resin as the main body, and achieves maximization of the comprehensive performance of the functional melamine optical coating through processes such as uniform mixing, coating, and sunlight curing with a cross-linking agent and a catalyst; the preparation of the functional melamine optical coating can be completed within 20 minutes, which can better meet the technical requirements of the coating application of melamine resin.

[0025] (4) After the functional melamine resin optical coating of the present invention is processed, its main performance indicators are as follows: light transmittance ≥98.0%, light refractive index 1.5590, water contact angle ≥100°, water resistance ≥9.0h, impact resistance ≥140mm, pencil hardness ≥5H, abrasion resistance ≤3.2mg / 100 turns, adhesion ≥7.10MPa, and high repetition rate. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below through specific implementation methods. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0027] It should be noted that the raw materials used in the various embodiments of the functional melamine resin optical coating that is cured by sunlight provided by the present invention can all be obtained through market channels.

[0028] Example 1

[0029] The invention provides a preparation method of a trifunctional melamine resin. The trifunctional melamine resin is composed of 126 parts of melamine, 243 parts of formaldehyde solution (37%), 50-150 parts of hydroxyethyl acrylate, 50-200 parts of polyol and 2-10 parts of photosensitizer by mass, and is obtained through an amination reaction. The specific amination reaction process is: 126 parts of melamine and 243 parts of formaldehyde solution are placed in a three-necked flask, heated to 80 DEG C, and cooled to 70 DEG C until a water tolerance point appears, and 50-150 parts of hydroxyethyl acrylate, 50-200 parts of polyol and 2-10 parts of photosensitizer are added, and stirred for 2 hours to obtain the trifunctional melamine resin.

[0030] Furthermore, Examples 2 to 6 adopt a preparation method similar to that of Example 1 and are configured according to the ratios shown in Table 1 below. The difference between Examples 2 to 6 and Example 1 is that the raw materials and the ratios of the trifunctional melamine resin are different.

[0031] Table 1 Material ratio of Examples 1 to 6 (unit of measurement: mass fraction) 1000045

[0032]

[0033] Example 7

[0034] The invention provides a method for preparing a functional melamine resin optical coating cured by sunlight. The trifunctional melamine resin in Example 1 is selected, and 100 parts of the trifunctional melamine resin, 1 part of TMPTA, and 10 parts of AA are mixed uniformly, applied, and cured by sunlight to obtain a coating prepared by using the functional melamine optical coating. The main performance indicators of the coating are as follows: light transmittance 98.2%, light refractive index 1.5589, water contact angle 103°, water resistance 10h, impact resistance 160mm, pencil hardness 5H, abrasion resistance 2.8mg / 100 revolutions, and adhesion 8.9MPa.

[0035] Furthermore, Examples 8 to 11 adopt a preparation method and a use method similar to Example 7, and are configured according to the ratios shown in Table 2 below. The difference between Examples 8 to 11 and Example 7 is that the raw materials and the ratios of the functional melamine resin optical coatings are different.

[0036] Table 2 Material ratio of Examples 7 to 11 (unit of measurement: mass fraction)

[0037]

[0038] Furthermore, the same test method was used to perform performance tests on Examples 7 to 11, and the test results are shown in Table 3 below.

[0039] Table 3 Performance parameters of Examples 7 to 11

[0040]

[0041] As can be seen from Table 3, the functional melamine resin optical coating provided by the present invention that is cured by sunlight has the following main performance indicators: light transmittance ≥98.0%, light refractive index ≈1.5590, water contact angle ≥100°, water resistance ≥9.0h, impact resistance ≥140mm, pencil hardness ≥5H, abrasion resistance ≤3.2mg / 100 turns, and adhesion ≥7.10MPa.

[0042] Obviously, it should be understood by those skilled in the art that the above-mentioned various steps of the present invention can be performed in a manner different from the present invention, and the simulation method and experimental equipment include but are not limited to the above description. The above-mentioned various steps of the present invention can be performed in an order different from that here in some cases, and the steps shown or described above can be performed separately. Therefore, the present invention is not limited to any specific combination of hardware and software.

[0043] The above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A functional melamine resin optical coating cured by sunlight, characterized in that: The functional melamine resin optical coating is composed of the following raw materials in parts by weight: 100 parts of trifunctional melamine resin, 1 to 10 parts of crosslinking promoter and 1 to 20 parts of catalyst; wherein the trifunctional melamine resin is composed of the following raw materials in parts by weight: 126 parts of melamine, 243 parts of formaldehyde solution, 50 to 150 parts of hydroxyethyl acrylate, 50 to 200 parts of polyol and 2 to 10 parts of photosensitizer, the concentration of the formaldehyde solution is 37%, and the trifunctional melamine resin is synthesized through an amination reaction.

2. The functional melamine resin optical coating cured by sunlight according to claim 1, characterized in that: The polyol is one or more of ethylene glycol, propylene glycol, glycerol, and polyethylene glycol.

3. A new structure melamine resin coating with convenient coating and curing process according to claim 2, characterized in that: The polyol is 80 parts of polyethylene glycol 400.

4. The functional melamine resin optical coating cured by sunlight according to claim 1, characterized in that: The photosensitizer is one or more of 2-hydroxy-2-methylpropiophenone, 4-[4,5-bis[4-(dimethylamino)phenyl]-1H-imidazol-2-yl]-2,6-dimethoxyphenol, and hydroxycyclohexylphenyl ketone.

5. The new structure melamine resin coating with convenient coating and curing process according to claim 4, characterized in that: The photosensitizer is 4 parts of 2-hydroxy-2-methylpropiophenone.

6. The functional melamine resin optical coating cured by sunlight according to claim 1, characterized in that: The crosslinking promoter is one or more of propane trimethanol triacrylate and pentaerythritol triacrylate.

7. The functional melamine resin optical coating cured by sunlight according to claim 6, characterized in that: The crosslinking promoter is 6 parts of propane trimethanol triacrylate.

8. The functional melamine resin optical coating cured by sunlight according to claim 1, characterized in that: The catalyst is one or more of acrylic acid, methacrylic acid and maleic acid.

9. The functional melamine resin optical coating cured by sunlight according to claim 8, characterized in that: The catalyst is 12 parts of acrylic acid.

10. A method for preparing a functional melamine resin optical coating cured by sunlight according to any one of claims 1 to 9, characterized in that: include: 126 parts of melamine and 243 parts of formaldehyde solution are placed in a three-necked flask, heated to 80°C, and when the water tolerance point appears, cooled to 70°C, 50-150 parts of hydroxyethyl acrylate, 50-200 parts of polyol and 2-10 parts of photosensitizer are added, and stirred for 2 hours to obtain a trifunctional melamine resin; The trifunctional melamine resin, the cross-linking agent and the catalyst are mixed according to a ratio to obtain the functional melamine resin optical coating, and the functional melamine resin optical coating is applied to the surface of an object, and is cured within 5 to 20 minutes under sunlight to obtain a coating. The coating has the following performance indicators: light transmittance ≥98.0%, light refractive index 1.5590, water contact angle ≥100°, water resistance ≥9.0h, impact resistance ≥140mm, pencil hardness ≥5H, abrasion resistance ≤3.2mg / 100 turns, and adhesion ≥7.10MPa.

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