Coatings, their preparation methods, and products including them

Abstract

This application relates to a coating, a method for preparing the same, and products comprising the same. The coating is formed from a raw material containing enol monomers via plasma-enhanced chemical vapor deposition. This application facilitates the simple preparation of coatings with excellent hydrophilicity and anti-fogging properties at relatively low temperatures.

Description

Technical Field

[0001] This invention relates to the field of surface treatment, and more particularly to a coating, a method for preparing the same, and products comprising the same. Background Technology

[0002] Common transparent optical materials used in production and daily life, such as quartz glass, silicate glass, polyethylene terephthalate, polymethyl methacrylate, polystyrene, polycarbonate, styrene-methyl methacrylate copolymer, and polyvinyl chloride, have water contact angles between 30 and 70 degrees, and the materials themselves have a certain degree of water droplet repulsion. Therefore, when the surface temperature of these materials is at their dew point, severe fogging occurs, leading to reduced material transmittance and consequently affecting the performance of the materials in various applications. For example, fogging in eyeglasses, automotive glass, bathroom glass, lens glass, surveillance domes, and automotive headlight covers can obstruct vision, while fogging in solar panels can reduce power generation efficiency. Therefore, various methods have been adopted to prevent fogging.

[0003] Currently, common anti-fogging methods include coating the surface of the target material with a superhydrophobic anti-fogging coating, a superhydrophilic anti-fogging coating, or a water-absorbing anti-fogging coating to prevent fogging. However, to date, the construction of superhydrophobic anti-fogging coatings generally employs a combination of micro / nano structures and low surface energy materials, resulting in complex, difficult, and costly manufacturing processes. Water-absorbing anti-fogging coatings primarily rely on the water-retaining properties of hydrophilic resins to achieve anti-fogging, typically prepared using thermosetting or photocuring methods. The coating thickness is in the micrometer range, and when used for film formation on irregularly shaped components with irregular structures or surfaces, severe sagging and uneven thickness occur, and fogging still occurs after water saturation. Therefore, superhydrophilic anti-fogging coatings have become an important means in the field of anti-fogging.

[0004] Chinese Patent Application Publication No. CN111499216A discloses a superhydrophilic antifogging coating based on titanium dioxide doping. In the preparation process of this superhydrophilic antifogging coating, a mixed solvent aging treatment is first performed to obtain titanium dioxide sol, followed by high-temperature annealing to obtain a coating with a water contact angle of less than 10 degrees. This coating preparation process requires temperatures reaching approximately 450℃ and annealing times as long as 1-2 hours, and it has high requirements for the substrate, limiting its application range.

[0005] Chinese Patent Announcement No. CN109868025B discloses a water-based self-crosslinking hydrophilic anti-fog coating. This super-hydrophilic anti-fog coating is made according to a composite formula containing hydrophilic polyacrylate, modified nano-silica sol and modified surfactant, with a water contact angle of 2-5 degrees. However, its preparation process uses more than a dozen reagents, making the formula complex. Summary of the Invention

[0006] The technical problems solved by the present invention include providing a coating with excellent hydrophilicity and anti-fogging properties that can be easily prepared at a lower temperature, a method for preparing the coating, and products comprising the coating.

[0007] One aspect of the present invention relates to a coating formed from a raw material containing enol monomers by plasma-enhanced chemical vapor deposition (PECVD).

[0008] Optionally, the enol monomer contains at least one carbon-carbon double bond and at least one hydroxyl group.

[0009] Optionally, the enol monomer includes at least one of 1,4-butenediol, 1-buten-3-ol, 3-penten-2-ol, cis-3-hexen-1-ol, and methanallyl alcohol.

[0010] Optionally, the raw material comprises amide monomers, wherein the molar ratio of the enol monomer to the amide monomer is 1:1 to 5:1.

[0011] Optionally, the amide monomer has the following structural formula:

[0012]

[0013] R1-R5 are each independently hydrogen, hydroxyl, or optionally substituted or unsubstituted branched or straight-chain alkyl groups.

[0014] Optionally, at least one of R1-R5 is a hydrophobic group.

[0015] Optionally, the amide monomer includes at least one of methacrylamide, N-hydroxymethylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N'-methylenebisacrylamide, and N-tert-butylacrylamide.

[0016] Optionally, the water contact angle of the coating is less than or equal to 10 degrees.

[0017] Optionally, the thickness of the coating is 1nm-1000nm.

[0018] Optionally, the coating has a transmittance greater than 90%.

[0019] Optionally, the color difference value of the coating is less than 1.

[0020] Optionally, the color difference value of the coating is less than 0.5.

[0021] Another aspect of the present invention relates to a method for preparing the coating described in this application, which includes the following steps: depositing the raw material onto the surface of a substrate using a PECVD method at a temperature of 30°C-80°C to form the coating.

[0022] Optionally, the step is performed at a temperature of 45°C.

[0023] Optionally, the method includes gasifying the raw material prior to the step.

[0024] Optionally, the gasification of the raw material is carried out at a temperature of 80°C-150°C.

[0025] Optionally, the method includes pretreating the substrate prior to the step.

[0026] Optionally, the pretreatment of the substrate is performed by solvent cleaning and / or plasma bombardment of the substrate.

[0027] Another aspect of the present invention relates to a product comprising a coating obtained by depositing the method described in this application.

[0028] Another aspect of the present invention relates to a product comprising the coating described in this application.

[0029] The technical solutions of the embodiments of the present invention can facilitate the simple preparation of coatings with excellent hydrophilicity and anti-fogging properties at lower temperatures, etc. Detailed Implementation

[0030] One aspect of this invention relates to a coating formed from a raw material containing enol monomers by a PECVD method.

[0031] The coating of this invention is formed by PECVD, which can be prepared at lower temperatures without affecting the original properties of the substrate and is simple to operate. PECVD technology polymerizes and crosslinks raw materials containing enol monomers, depositing them on the substrate surface to form a coating without requiring complex raw material formulations. The resulting coating surface has a large number of hydroxyl groups, which provide hydrophilic properties and achieve excellent hydrophilic effects. Therefore, the coating deposited on the substrate surface forms a hydrophilic surface, where water droplets can spread and form a film, eliminating diffuse reflection of light and thus achieving excellent anti-fogging effects.

[0032] PECVD technology can be widely applied to most substrates. It not only does not damage the intrinsic properties of the substrate, but also allows enol monomers to easily form a relatively uniform thin coating on the substrate. When coating substrates with irregular structures, it can effectively avoid the sagging phenomenon caused by the thick coating formed by conventional spraying and dip coating processes. It has strong applicability to substrates with irregular structures. In addition, the uniformity of the coating is easy to control, the coating time is relatively short, and it can effectively eliminate the adverse effects of substrate fogging.

[0033] Therefore, the technical solution of the present invention can facilitate the simple preparation of coatings with excellent hydrophilicity and anti-fogging properties at lower temperatures, and can also help to achieve coatings with short coating time, wide application range, uniform thickness, dense structure, good wear resistance, and avoid sagging when coating substrates with irregular structures, etc.

[0034] Optionally, the enol monomer contains at least one carbon-carbon double bond and at least one hydroxyl group.

[0035] In this embodiment of the invention, the enol monomer may contain any number of carbon-carbon double bonds and hydroxyl groups, as long as its molecular structure simultaneously contains both carbon-carbon double bonds and hydroxyl groups. This facilitates the polymerization and cross-linking of the enol monomer to form a hydrophilic anti-fog coating.

[0036] Optionally, the enol monomer includes at least one of 1,4-butenediol, 1-buten-3-ol, 3-penten-2-ol, cis-3-hexen-1-ol, and methanallyl alcohol.

[0037] Optionally, the raw material comprises amide monomers, wherein the molar ratio of the enol monomer to the amide monomer is 1:1 to 5:1.

[0038] In the coating formation process of this invention, the carbon-carbon double bonds in the enol monomers are opened by plasma activation, and the enol monomers with opened double bonds can combine with each other to form a network structure. The double bonds in the amide monomers can combine with the carbon-carbon double bonds or hydroxyl groups in the enol monomers, increasing the degree of crosslinking and curing of the coating, improving the crosslinking rate, deposition rate, and film formation rate of the coating, reducing the film formation temperature, and simultaneously maintaining the high hydrophilicity and high durability of the coating.

[0039] In this embodiment of the invention, unless otherwise specifically indicated, the numerical range may include any sub-range therein, for example, 1:1-5:1 may include 1:1-2:1, 1:1-3:1, 1:1-4:1, and so on.

[0040] Optionally, the amide monomer has the following structural formula:

[0041]

[0042] R1-R5 are each independently hydrogen, hydroxyl, or optionally substituted or unsubstituted branched or straight-chain alkyl groups.

[0043] "Optionally substituted or unsubstituted branched or straight-chain alkyl" means that it can be an unsubstituted branched or straight-chain alkyl, or a branched or straight-chain alkyl substituted with one or more substituents. Here, the substituents can be selected, for example, from alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclic, carboxyl, carboxylate ion, carboxylate ester, urethane, alkoxy, ketone, aldehyde, amino, amide, hydroxyl, cyano, nitro, and halogen atoms. However, the invention is not limited thereto.

[0044] Optionally, at least one of R1-R5 is a hydrophobic group.

[0045] Here, the hydrophobic group can be any hydrophobic group selected from the above-mentioned "optionally substituted or unsubstituted branched or straight-chain alkyl groups", for example, it can be methyl, ethyl, propyl, tert-butyl, etc.

[0046] Optionally, the amide monomer includes at least one of methacrylamide, N-hydroxymethylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N'-methylenebisacrylamide, and N-tert-butylacrylamide.

[0047] Optionally, the water contact angle of the coating is less than or equal to 10 degrees.

[0048] Preferably, the water contact angle of the coating is less than or equal to 9 degrees. Therefore, the coating has excellent hydrophilic properties and can be used to effectively prevent fogging on the substrate surface, thus exhibiting excellent anti-fogging performance.

[0049] Optionally, the thickness of the coating is 1nm-1000nm.

[0050] In this embodiment of the invention, the thickness of the coating can be controlled within the range of 1nm-1000nm, or even at the micrometer level, depending on actual needs.

[0051] Optionally, the coating has a transmittance greater than 90%.

[0052] The coating has virtually no impact on the transmittance and light transmission performance of the substrate.

[0053] Optionally, the color difference value of the coating is less than 1.

[0054] Optionally, the color difference value of the coating is less than 0.5.

[0055] The coating has virtually no effect on the color difference of the substrate.

[0056] Another aspect of the present invention relates to a method for preparing the coating described in this application, which includes the following steps: depositing the raw material onto the surface of a substrate using a PECVD method at a temperature of 30°C-80°C to form the coating.

[0057] In this embodiment of the invention, the PECVD method can deposit the raw material onto the substrate surface at a temperature of 30°C-80°C to form the coating. Compared with other existing methods, such as coating processes that require thermal curing at temperatures up to several hundred degrees, the coating temperature is much lower.

[0058] Optionally, the step is performed at a temperature of 45°C.

[0059] Optionally, the method includes gasifying the raw material prior to the step.

[0060] For example, the raw material can be vaporized in an evaporator, activated by plasma, and deposited onto the substrate surface to easily and uniformly form a coating with a nanometer thickness. Furthermore, when coating a substrate with an irregular structure, no sagging occurs.

[0061] In this embodiment of the invention, the raw material can be vaporized at any applicable temperature. Optionally, the vaporization of the raw material is carried out at a temperature of 80°C-150°C. The specific vaporization temperature of the raw material can be determined according to its specific composition.

[0062] Optionally, the method includes pretreating the substrate prior to the step.

[0063] Pre-treating the substrate before coating can help improve the adhesion between the coating and the substrate.

[0064] Optionally, the pretreatment of the substrate is performed by solvent cleaning and / or plasma bombardment. However, the present invention is not limited thereto. In embodiments of the present invention, any suitable means may be used to pretreat the substrate.

[0065] Another aspect of the present invention relates to a product comprising a coating obtained by depositing the method described in this application.

[0066] Another aspect of the present invention relates to a product comprising the coating described in this application.

[0067] The products may include, for example, eyeglasses, goggles, laser protective glasses, telescopes and lenses of various camera equipment, observation windows of various machines, sports diving masks, bathroom glass, chemical or biological protective masks, vehicle windshields and rearview mirrors, bomb disposal protective equipment, helmets, solar panels, observation windows of measuring instruments, glass covers, glass walls of greenhouses, etc.

[0068] The technical solution of this invention can facilitate the simple preparation of coatings with excellent hydrophilicity and anti-fogging properties at lower temperatures, and can also help to achieve uniform coating thickness, fast deposition rate, avoid sagging when coating irregularly shaped components, and have a wide range of applications, etc.

[0069] The embodiments of the present invention will be illustrated below with specific examples. These examples are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0070] Example 1

[0071] A transparent glass substrate (length: 13cm, width: 6.5cm, thickness: 1mm) was placed in a 500L plasma vacuum reaction chamber. The reaction chamber was continuously evacuated to a vacuum level of 80 mTorr. The internal temperature of the chamber was controlled at 45℃, and helium gas was introduced at a flow rate of 40 sccm.

[0072] The glass substrate was pretreated as follows: the gas pressure in the cavity was kept at 80 mTorr and the helium flow rate was 40 sccm. Radio frequency plasma discharge was turned on, the radio frequency energy output mode was continuous discharge, the discharge time was 300s, and the discharge power was 300w.

[0073] 1,4-Butenediol and methacrylamide were mixed at a molar ratio of 5:1 and stirred at room temperature for 10 minutes to obtain a uniform coating material. The coating material was then loaded into the plasma equipment feed tank, vaporized, and introduced into the plasma vacuum reaction chamber. The coating material flow rate was 120 μL / min, the vaporization temperature was 110°C, the chamber pressure was maintained at 80 mTorr, and the helium flow rate was 40 sccm. Subsequently, radio frequency plasma discharge was initiated, with pulsed energy output, a discharge time of 1800 s, a discharge power of 80 W, a pulse frequency of 50 Hz, and a pulse duty cycle of 45%.

[0074] After the coating preparation is completed, air is introduced to restore the reaction chamber to normal pressure. Then, the chamber is opened and the glass substrate with the coating deposited on its surface is taken out as the coating sample.

[0075] Example 2

[0076] The coating was prepared in the same manner as in Example 1, except that 1,4-butenediol and methacrylamide were mixed in a molar ratio of 4:1.

[0077] Example 3

[0078] The coating was prepared in the same manner as in Example 2, except that N-hydroxymethylacrylamide was used instead of methacrylamide.

[0079] Example 4

[0080] The coating was prepared in the same manner as in Example 2, except that N,N-dimethylacrylamide was used instead of methacrylamide, and 1,4-butenediol and N,N-dimethylacrylamide were mixed in a molar ratio of 3:1.

[0081] Example 5

[0082] The coating was prepared in the same manner as in Example 4, except that 1-buten-3-ol was used instead of 1,4-butendiol.

[0083] Example 6

[0084] The coating was prepared in the same manner as in Example 4, except that 3-penten-2-ol and N,N-diethylacrylamide were used instead of 1,4-butenediol and N,N-dimethylacrylamide, respectively.

[0085] Example 7

[0086] The coating was prepared in the same manner as in Example 4, except that cis-3-hexen-1-ol and N,N′-methylenebisacrylamide were used instead of 1,4-butenediol and N,N-dimethylacrylamide, respectively.

[0087] Example 8

[0088] The coating was prepared in the same manner as in Example 4, except that methyl allyl alcohol and N-tert-butylacrylamide were used instead of 1,4-butenediol and N,N-dimethylacrylamide, respectively.

[0089] Example 9

[0090] The coating was prepared in the same manner as in Example 1, except that a transparent glass substrate with a length of 75 mm, a width of 26 mm, and a thickness of 1 mm was selected as the substrate, and no methacrylamide was added.

[0091] Example 10

[0092] The coating was prepared in the same manner as in Example 1, except that a transparent glass substrate with a length of 75 mm, a width of 26 mm, and a thickness of 1 mm was selected as the substrate, and no pretreatment was performed on the glass substrate.

[0093] Comparative Example

[0094] Uncoated, transparent glass substrates were selected as samples for coating.

[0095] Example 11. Testing Coating Thickness

[0096] The thickness of the coatings prepared in each embodiment and comparative example was measured using a Filmetrics F20-UV thin film thickness gauge (USA) with a 9-point measurement method. Specifically, nine evenly distributed sites were selected on the surface of the coated samples in each embodiment and comparative example as measurement locations, and the coating thickness at each measurement location was measured. The measurement results are summarized in Table 1 below.

[0097] Table 1. Coating thickness (unit: nm)

[0098]

[0099] Note: The nine measurement locations are labeled 1-9 in order from top to bottom and from left to right.

[0100] Referring to Table 1, a comparison of the coating thicknesses in Examples 1-10 with those in the comparative examples shows that the present invention can effectively form a uniform coating of nanoscale thickness on the substrate surface using raw materials containing enol monomers (optionally containing amide monomers) through the PECVD process.

[0101] Furthermore, as shown in Table 1, the coating thicknesses prepared in Examples 1-8 and 10 are 2-3 times greater than the coating thickness prepared in Example 9. This indicates that adding amide monomers to raw materials containing enol monomers can effectively increase the deposition rate of the coating, and the rate can be significantly increased by 2-3 times.

[0102] Example 12. Testing the transmittance of the coating

[0103] The transmittance of the coated samples in each example and comparative example was measured using a Perkin-Elmer-Lambda 950 UV-Vis spectrophotometer. The transmittance of the coatings prepared in each example was calculated according to GB / T11186.3-1989 standard. The results are shown in Table 2 below.

[0104] Table 2. Coating test results

[0105]

[0106] Where T represents transmittance.

[0107] As shown in Table 2, the transmittance of the coatings prepared in Examples 1-10 is greater than 90%, indicating that the coatings of the present invention are transparent and have almost no effect on the transmittance of the substrate.

[0108] Example 13. Testing the color difference value of the coating

[0109] The Lab values ​​of the coated samples in each example and comparative example were measured using a Konica Minolta CM-5 spectrophotometer. The measured Lab values ​​were determined according to the GB / T11186.3-1989 standard and formula. The color difference values ​​of the coatings prepared in each embodiment were calculated. Here, ΔE represents the color difference value of the coating, and ΔL, Δa, and Δb represent the differences in L, a, and b values ​​between the coated samples in Examples 1-10 and the coated samples in the comparative examples, respectively. The results are shown in Table 2 above.

[0110] As shown in Table 2, the color difference values ​​of the coatings prepared in Examples 1-10 are all less than 0.5, indicating that the coatings of the present invention have almost no effect on the color difference of the substrate.

[0111] Example 14. Testing the water contact angle of the coating

[0112] The water contact angles of the coated samples in each example and comparative example were measured according to the standard GB / T 30447-2013 "Method for measuring contact angle of nanofilms". The results are shown in Table 2 above.

[0113] As shown in Table 2, the water contact angle of the coatings prepared in Examples 1-10 is less than 10 degrees, indicating that the coatings of the present invention have excellent hydrophilic properties. Furthermore, by changing the types of enol monomers and amide monomers, the resulting coatings also have hydrophilic effects.

[0114] Example 15. Testing the anti-fogging performance of the coating

[0115] The coated samples from each embodiment and comparative example were placed in a 95°C constant temperature water bath with the coating surface facing the water vapor, and the distance between the water surface and the coating surface was 5 cm. After 10 minutes, it was observed whether the coating surface fogged up. If a uniform water film formed on the coating surface and the field of view was clear, it was marked as OK; if the coating surface fogged up, it was marked as NG. The results are shown in Table 2 above.

[0116] As shown in Table 2, the coatings prepared in Examples 1-10 can all effectively prevent surface fogging, indicating that the coatings of the present invention have excellent anti-fogging performance.

[0117] Example 16. Testing the abrasion resistance of the coating

[0118] The abrasion resistance of the coatings prepared in each example and comparative example was tested using a linear abrasion tester manufactured by Taber Corporation with a load of 10 N. The friction medium was cotton cloth with a thread length of 4 cm, a speed of 40 r / min, and 1000 cycles of friction. The water contact angle values ​​of the coatings prepared in each example and comparative example after friction were measured and recorded according to GB / T30447-2013 "Method for Measurement of Contact Angle of Nanofilms". The results are shown in Table 2 above.

[0119] Referring to Table 2, it can be seen that the water contact angles of the coatings prepared in Examples 1-8 are all less than 10 degrees before and after friction, while the water contact angles of the coatings prepared in Examples 9 and 10 are less than 10 degrees before friction and greater than 10 degrees after friction. The water contact angle of the coating prepared in Example 10 after friction is larger than that in Example 9. This indicates that the coating formed by compounding enol monomers and amide monomers has higher density and better wear resistance; and the plasma pretreatment before coating can effectively clean the substrate surface, improve the adhesion between the coating and the substrate, and thus significantly improve the wear resistance of the coating.

[0120] In summary, the technical solution of this invention can easily prepare a transparent coating with excellent hydrophilicity and anti-fogging properties from raw materials containing enol monomers or containing both enol monomers and amide monomers at a relatively low temperature using the PECVD method, without changing the original properties of the substrate. Furthermore, the resulting coating has a short coating time, uniform and controllable thickness, dense structure, good wear resistance, and a wide range of applications.

[0121] The technical solutions of this invention can provide anti-fog coatings applicable to various materials such as glass and plastic substrates, and can ultimately be manufactured into products with super-hydrophilic anti-fog coatings, such as glasses, goggles, laser protective glasses, telescopes and lenses of various camera equipment, observation windows of various machines, sports diving masks, bathroom glass, chemical or biological protective masks, vehicle windshields and rearview mirrors, bomb disposal protective equipment, helmets, solar panels, observation windows of measuring instruments, glass covers, and glass walls of greenhouses.

[0122] The various specific embodiments described above are for illustrative purposes only and do not represent the entirety of the invention. Any modifications made by those skilled in the art within the scope of the basic technical concept of this invention are within the protection scope of this invention.

Claims

1. A coating characterized in that, formed by a plasma enhanced chemical vapor deposition method from a starting material comprising an enolic monomer and an amide monomer, the amide monomer having the following structural formula: ， wherein R1-R5 are each independently hydrogen, hydroxyl, optionally substituted or unsubstituted branched or straight chain alkyl, at least one of R1-R5 being a hydrophobic group.

2. The coating of claim 1, wherein, the enolic monomer comprising at least one carbon-carbon double bond and at least one hydroxyl group.

3. The coating of claim 1, wherein, the enolic monomer including at least one of 1,4-butanediol, 1-buten-3-ol, 3-penten-2-ol, cis-3-hexen-1-ol, and methallyl alcohol.

4. The coating of claim 1, wherein, the molar ratio of the enolic monomer to the amide monomer is 1:1 to 5:

1.

5. The coating of claim 4, wherein, the amide monomer including at least one of methacrylamide, N-hydroxymethyl acrylamide, N,N-dimethyl acrylamide, N,N-diethyl acrylamide, N,N'-methylenebisacrylamide, and N-tert-butyl acrylamide.

6. The coating of any one of claims 1-5, wherein, the water contact angle of the coating is less than or equal to 10 degrees.

7. The coating of any one of claims 1-5, wherein, the thickness of the coating is 1 nm to 1000 nm.

8. The coating of any one of claims 1-5, wherein, the transmittance of the coating is greater than 90%.

9. The coating of any one of claims 1-5, wherein, the color difference value of the coating is less than 1.

10. The coating of any one of claims 1-5, wherein, the color difference value of the coating is less than 0.

5.

11. A method of preparing a coating as claimed in any one of claims 1 to 10, characterised in that, comprising the steps of: depositing the starting material on a surface of a substrate at a temperature of 30°C to 80°C using a plasma enhanced chemical vapor deposition method to form the coating.

12. The method of claim 11, wherein, the step is performed at a temperature of 45°C.

13. The method of claim 11, wherein, comprising vaporizing the starting material prior to the step.

14. The method of claim 13, wherein, the vaporizing the starting material is performed at a temperature of 80°C to 150°C.

15. The method of claim 11, wherein, comprising pretreating the substrate prior to the step.

16. The method of claim 15, wherein, the pretreating the substrate is performed by solvent cleaning and / or plasma bombardment of the substrate.

17. A product characterized by, a coating formed by the method of any one of claims 11-16.

18. A product characterized by, a coating as claimed in any one of claims 1-10.

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