WO2020082682A1

WO2020082682A1 - High-transparency low-color-difference nano coating and preparation method therefor

Info

Publication number: WO2020082682A1
Application number: PCT/CN2019/079117
Authority: WO
Inventors: 宗坚
Original assignee: 江苏菲沃泰纳米科技有限公司
Priority date: 2018-10-24
Filing date: 2019-03-21
Publication date: 2020-04-30
Also published as: CN109267041B; TW202016349A; TWI745769B; CN109267041A

Abstract

A high-transparency low-color-difference nano coating. A substrate is exposed in a monomer steam atmosphere, and a chemical reaction occurs on the surface of the substrate by means of plasma discharge to form a protective coating. Monomer steam is a vaporized monomer 1 or monomer 2, or a mixture thereof. The monomer 1 and the monomer 2 have specific structures. Also disclosed is a preparation method for a high-transparency low-color-difference nano coating.

Description

Nano-coating with high transparency and low color difference and preparation method thereof

Technical field

The invention relates to the technical field of plasma chemical vapor deposition, in particular to a high-transparent low-color-difference nano protective coating and a preparation method thereof.

Background technique

The intrusion of liquid and moisture is one of the most important causes of PCB board corrosion and short circuit in electronic devices. Polymer coatings are often used for the protection of material surfaces due to their advantages such as economy, easy coating, wide application range, and good chemical resistance. The polymer coating blocks the intrusion of liquids, especially water and steam, thereby improving the adaptability of electronic devices in a humid environment, and making important product indicators such as quality stability and reliability, service life of electronic devices to a great extent improve.

At present, there are mainly two methods for applying a protective layer on the PCB board according to the state of the material, liquid phase coating and vapor deposition. Liquid phase coating, such as three-proof paint, the construction method can use dipping method, brushing method, spraying method and other processes, the liquid phase raw material is applied on the surface of the substrate and then thermally cured, light cured and other means to form dense, cross-linked Polymer coating. However, the liquid-phase coating method generates a large amount of exhaust gas and waste liquid, and the raw material utilization rate is low. At the same time, the solvent used often causes certain damage to the PCB of the electronic device; in addition, the thickness of the three anti-paint is more than tens of microns The uniformity of the thickness is poor, which has a great impact on the functions of some electronic devices that require heat dissipation and signal transmission. In contrast, the vapor deposition method, especially the plasma chemical vapor deposition method, is a method that uses plasma to activate the reactive gas and perform chemical vapor deposition on the substrate surface. This method is suitable for the protection requirements of various substrate surfaces: vapor-phase coating can be uniformly deposited on substrates of different shapes; the coating preparation temperature is low, suitable for the protection of temperature-sensitive devices; the coating is thin and the stress is small, Less damage to PCB. At present, the protective material on the PCB is mainly fluorocarbon resin, but the coefficient of friction of the fluorocarbon resin is very low, it is easy to slide and deform under the action of external force, and it is not resistant to friction. By adding a cross-linking agent, the fluorocarbon resin layer can be improved. The force of the coating makes the coating more dense and enhances the protective ability of the coating to resist wear and corrosion. CN107058979 "Preparation method of waterproof and electrical breakdown resistant coating" In the fluorocarbon resin monomer, multifunctional unsaturated hydrocarbon derivatives are introduced to improve the product's resistance to corrosion and underwater energization. However, the coating formed by the selected multifunctional saturated hydrocarbon derivatives is generally high in crystallinity. When the coating reaches a certain thickness, light reflection, refraction, birefringence and other discoloration phenomena are obvious, and a rainbow on the surface occurs. , Which often severely affects the appearance of the product. How to reduce the crystallinity of the coating through molecular design and reduce the discoloration caused by the coating after plating is one of the technical problems that need to be solved urgently in the application field of nano-coatings in electronic products.

Summary of the invention

In order to overcome the above shortcomings, the present invention provides a high-transparency, low-color-difference nano-coating and a preparation method thereof to solve the problem of discoloration of the nano-coating on the product surface.

The present invention is achieved through the following technical solutions:

A nano-coating on the surface of high-transparency and low-color-difference products, which exposes the substrate to the atmosphere of monomer vapor, and a chemical reaction occurs on the surface of the substrate through plasma discharge to form a protective coating;

The monomer vapor is vaporized monomer 1 or monomer 2, or a mixture of monomer 1 and monomer 2, that is, monomer vapor is one or a mixture of vaporized monomer 1 and monomer 2 ;

The monomer 1 has the structure represented by the following formula (I); the monomer 2 has the structure represented by the following formula (II);

Monomer 1:

Monomer 2:

Among them, R ¹ and R ² are groups connected to the vinyl group, and conventional organic groups can be selected, preferably hydrogen, alkyl, aryl, halogen or haloalkyl.

Y and Z are bridging groups, which can be non-polar groups such as alkyl subunits or strong polar groups to improve the adhesion between the coating and the substrate, preferably -O-, -CO -, -COO- and -CONH- one or several connected groups.

R ³ is a group containing a large steric hindrance group. The presence of the large steric hindering group reduces the crystallinity of the coating. It may be a fatty alkane subunit containing 2 or more branched carbon atoms, an aryl subunit, and a cycloalkane subunit. Groups, or aliphatic alkyl subunits, aryl subunits, cycloalkane subunits substituted with hydroxyl, halogen, or carbonyl.

R ⁴ , R ⁵ and R ⁶ are groups connected to the double bond, and may be electron-donating groups or electron-withdrawing groups, preferably independently selected from hydrogen, alkyl, aryl, halogen, haloalkyl, Alkenyl or haloalkenyl, X is hydrogen or halogen. Preferably, X is a fluorine element, and the fluorinated alkyl group contains a CF bond. The bond energy is much higher than the CO and CC bonds, which can greatly improve the hydrophobicity and chemical resistance of the monomer.

m, n, and k are integers of 0-8; l is an integer of 1-20.

Further, R ³ is a group having a cyclic structure, preferably an aryl subunit or a cyclohexane subunit.

Preferably, m, n, k are 0, 1, 2 or 3.

Preferably, Y and Z are oxygen atom-containing groups with high adhesion to the substrate, and can be independently selected from one of -O-, -CO-, and -COO-, or a combination bond of several connections.

The coating can be applied to a substrate with a smooth surface or a substrate with a rough surface. The substrate may be an optical instrument, a metal surface, an electronic device, a fabric, or the like.

In addition, the invention also discloses a method for preparing the above nano-coating, which includes the following steps:

(1) Place the substrate in the reaction chamber of the plasma chamber, the vacuum degree in the reaction chamber is 0.0001-1000 mTorr;

(2) Inject the plasma source gas, start the plasma discharge for deposition, and vaporize monomer 1 and / or monomer 2 into the reaction chamber for chemical vapor deposition reaction;

(3) Turn off the plasma discharge for deposition, pass clean compressed air or inert gas to return to normal pressure, open the cavity, and take out the substrate.

When the monomer 1 and the monomer 2 are introduced into the reaction chamber, they can be introduced separately or at the same time; one monomer can be introduced first and then two monomers can be introduced simultaneously. Moreover, the molar ratio of monomer 1 and monomer 2 can be introduced in any ratio. Monomer 1 and monomer 2 are passed into the reaction chamber after being atomized and vaporized below one atmospheric pressure.

The plasma source gas in step (2) may be one or a mixture of several kinds of helium, argon, nitrogen, and hydrogen.

Preferably, the volume of the reaction chamber of the plasma chamber is 1L-5000L, the flow rate of the plasma source gas is 5-1000 sccm, and the flow rate of the monomer vapor is 1-2000 μL / min.

Preferably, in the step (2), after the plasma source gas is introduced and before the plasma discharge for deposition, a plasma discharge step for pretreatment of the substrate is further included.

After the plasma source gas is introduced in step (2), the pretreatment is started to perform pretreatment on the substrate with plasma discharge. The power of plasma discharge in this pretreatment stage is 2-500W, and the continuous discharge time is 1-5400s.

After the pretreatment phase ends, it enters the deposition phase (the plasma discharge for pretreatment is converted to the plasma discharge for deposition). The plasma discharge method and parameters of the two phases may be the same or different.

Further, in the step (2), the power of the plasma discharge for deposition is 2-500 W, and the continuous discharge time is 600-20000s.

Wherein, the plasma discharge (plasma discharge for pretreatment and / or plasma discharge for deposition) is radio frequency discharge, microwave discharge, intermediate frequency discharge, Penning discharge or electric spark discharge.

Further, the plasma discharge (plasma discharge for pretreatment and / or plasma discharge for deposition) is a radio frequency discharge, and the energy output method for controlling the plasma radio frequency during the radio frequency discharge is pulse or continuous output, and the plasma radio frequency When the energy output mode is pulse output, the pulse width is 10μs-50ms and the repetition frequency is 20Hz-10kHz.

Compared with the prior art, the introduction of large-volume groups in the monomer destroys the crystal order of the polymer chain during the polymerization process, reduces the crystallinity of the overall coating, and reduces the scattering, reflection, and The degree of anisotropy is refracted, which further reduces the color appearance of the product surface coating, and also increases the contact angle of the substrate surface and improves the hydrophobicity of the coating surface.

detailed description

Example 1

A method for preparing a nano-coating on the surface of a product with high transparency and low color difference. The method for preparing the nano-coating undergoes the following steps:

(1) Place the optical lens in the reaction chamber of the plasma chamber, continuously evacuate the reaction chamber, draw the vacuum degree in the reaction chamber to 100 mtorr, pass argon gas, and the flow rate is 100 sccm;

(2) Turn on the radio frequency plasma discharge to pretreat the optical lens substrate (that is, turn on the radio frequency mode pretreatment plasma discharge), the discharge power in this pretreatment stage is 10W, and the discharge is continued for 100s;

(3) The monomer 1a and the monomer 2a are vaporized and introduced into the reaction chamber for chemical vapor deposition reaction; the flow rate of the monomer 1a is 200μL / min for 1000s; after the end, the flow rate of the monomer 2a is 100μL / min for 400s. The plasma discharge for pretreatment is adjusted to the plasma discharge for deposition. The plasma in the deposition stage is generated by radio frequency discharge, the output mode is pulse, the pulse width is 2 μs, the repetition frequency is 500 Hz, the discharge power is 50 W, and the discharge time is the same as the monomer inflow time.

(4) After the preparation of the coating is completed, the radio frequency is turned off, nitrogen gas is introduced to restore the reaction chamber to normal pressure, the chamber is opened, and the optical lens is taken out.

Among them, the device for plasma discharge for pretreatment and the device for plasma discharge for deposition may be one set or two separate sets of devices. The plasma discharge device (for example, electrode) for pretreatment is preferably arranged in the reaction chamber and around the base material, so as to facilitate the quick connection with the coating process after pretreatment; the plasma discharge device for deposition can be arranged in the reaction chamber It is placed outside and away from the reaction chamber, so that the negative impact of plasma discharge on the substrate during the coating process can be selectively or as far as possible avoided.

Example 2

(1) Place the metal magnesium sheet in the reaction chamber of the plasma chamber, continuously evacuate the reaction chamber, evacuate the vacuum degree in the reaction chamber to 20 mTorr, pass argon gas, and the flow rate is 50 sccm;

(2) Turn on the radio frequency plasma discharge to pretreat the metal magnesium sheet substrate (that is, turn on the radio frequency mode pretreatment plasma discharge), the discharge power in this pretreatment stage is 30W, and the continuous discharge is 200s;

(3) The monomer 1b and monomer 2b are vaporized and then introduced into the reaction chamber for chemical vapor deposition reaction; the monomer 1b and 2b are simultaneously introduced, the monomer 1b flow rate is 250 μL / min, and the monomer 2b flow rate is 150 μL / min For 1000s. The plasma discharge for pretreatment is adjusted to the plasma discharge for deposition.

In this deposition stage, the plasma in the chamber is generated by radio frequency discharge, the output mode is pulse, the pulse width is 1ms, the repetition frequency is 400Hz, the discharge power is 50W, and the discharge time is the same as the monomer pass-through time.

(4) After the preparation of the coating is completed, the radio frequency is turned off, nitrogen gas is introduced to restore the reaction chamber to normal pressure, the chamber is opened, and the metal magnesium sheet is taken out.

Example 3

(1) Place the metal copper sheet in the reaction chamber of the plasma chamber, continuously evacuate the reaction chamber, draw the vacuum degree in the reaction chamber to 900 mtorr, pass argon gas, and the flow rate is 800 sccm;

(2) Turn on the radio frequency plasma discharge to pretreat the metal copper sheet substrate (that is, turn on the radio frequency mode pretreatment plasma discharge), the discharge power in this pretreatment stage is 60W, and the continuous discharge is 200s;

(3) The monomer 1c and monomer 2c are vaporized and then introduced into the reaction chamber for chemical vapor deposition reaction; the flow rate of monomer 1c is 250μL / min for 2000s; after the end, the flow rate of monomer 2c is 50μL / min for 600s.

The plasma discharge for pretreatment is adjusted to the plasma discharge for deposition. In this deposition stage, the plasma in the chamber is generated by radio frequency discharge, the output mode is pulse, the pulse width is 1ms, the repetition frequency is 400Hz, the discharge power is 50W, and the discharge time is the same as the monomer pass-through time.

(5) After the preparation of the coating is completed, the radio frequency is turned off, nitrogen gas is introduced to restore the reaction chamber to normal pressure, the chamber is opened, and the copper sheet is taken out.

Example 4

Compared with Example 1, the monomers 1a and 2a in step (3) were replaced with 1d and 2d, respectively, the monomer 1d passage time was 2500s, and the monomer 2d passage time was 500s.

Example 5

Compared with Example 1, the monomers 1a and 2a of step (3) were replaced with 1e and 2e, respectively, the monomer 1e introduction time was 3500s, and the monomer 2e introduction time was 700s.

Example 6

Compared with Example 1, the vacuum degree of the reaction chamber in step (1) was changed to 50 mTorr, and other conditions were unchanged.

Example 7

Compared with Example 2, the flow rate of monomer 1b in step (4) was changed to 400 μL / min, and other conditions were unchanged.

Example 8

Compared with Example 2, the duration of monomer introduction in step (4) was changed to 1500s, and other conditions remained unchanged.

Example 9

Compared with Example 3, in step (4), 1c is not introduced, and the replacement is: the monomer 2c is introduced with a flow rate of 250 μL / min for 2000 s; then the monomer 2c is introduced with a flow rate of 50 μL / min for 600 s. Other conditions are not changed.

Example 10

Compared with Example 3, in step (4), 2c is not introduced, and the replacement is: the monomer 1c is introduced with a flow rate of 250 μL / min for 2000 s; then the monomer 1c is introduced with a flow rate of 50 μL / min for 600 s. Other conditions are not changed.

The substrates after the plating in the above embodiments were subjected to the measurement of coating thickness, water contact angle, crystallinity, color difference, and abrasion resistance.

The thickness of the nano-coating is tested using the US Filmetrics-F20-UV-film thickness measuring instrument.

Nano-coating water contact angle is tested according to GB / T 30447-2013 standard. The crystallinity test method uses the Japanese Rigaku D / MAX-3B automatic X-ray diffractometer, Cu and Kα rays, λ = 154.06pm, the scanning speed is 3 ° / min, and the scanning range (2θ) is 5 ° -65 °.

The color difference test method is calculated according to the GB 11186.3-1989 standard. The Minolta CR-10 portable color difference meter is used to detect the total color difference ΔE.

The abrasion resistance test is conducted in an alcohol abrasion tester, and the eraser test fixture is selected for the test. The test condition is a load of 100g and a rotation speed of 40rpm.

Table 1

The invention utilizes the introduction of a large steric hindrance monomer in the preparation process of the coating to prepare a hydrophobic nanocomposite coating, which reduces the crystallinity of the coating, the total color difference is ΔE <2.0, and the hydrophobicity and abrasion resistance of the coating are less Fluorocarbon resin coating is excellent.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements do not deviate from the essence of the corresponding technical solutions of the technical solutions of the embodiments of the invention range.

Claims

A nano-coating on the surface of high-transparency and low-color-difference products, which exposes the substrate to the atmosphere of monomer vapor, and a chemical reaction occurs on the surface of the substrate through plasma discharge to form a protective coating;

The monomer vapor is one or a mixture of the vaporized monomer 1 and monomer 2; the monomer 1 has the structure represented by the following formula (I); the monomer 2 has the following formula (II) The structure shown;

Monomer 1:

Monomer 2:

Wherein R 1 and R 2 are independently selected from hydrogen, alkyl, aryl, halogen or haloalkyl; Y and Z are independently selected from bond, -O-, alkyl subunit, -CO-, -COO- and -CONH- one or several connected groups;

R 3 is a fatty alkane subunit containing 2 or more branched carbon atoms, an aryl subgroup, or a cycloalkane subunit, or a branched aliphatic alkyl group containing a branch, a aryl subunit substituted with a hydroxyl group, a halogen, or a carbonyl group Or cycloalkane subunits;

R 4 , R 5 and R 6 are independently selected from hydrogen, alkyl, aryl, halogen, haloalkyl, alkenyl or haloalkenyl; X is selected from hydrogen or halogen;

m, n, and k are integers of 0-8; l is an integer of 1-20.
The nano-coating on the surface of a high-transparency, low-color-difference product according to claim 1, wherein R 3 is an aryl subunit or a cyclohexane subunit.
The nano-coating on the surface of the highly transparent and low-chromaticity product according to claim 1, wherein m, n, and k are 0, 1, 2, or 3.
The nano-coating on the surface of a product with high transparency and low color difference according to claim 1, wherein the substrate is an optical instrument, a metal surface, an electronic device or a fabric.
A method for preparing a nano-coating on the surface of a product with high transparency and low color difference according to any one of claims 1 to 4, characterized in that it comprises the following steps:

(1) Place the substrate in the reaction chamber of the plasma chamber, the vacuum degree in the reaction chamber is 0.0001-1000 mTorr;

(2) Inject the plasma source gas, start the plasma discharge for deposition, and introduce the monomer vapor into the reaction chamber to carry out the chemical vapor deposition reaction;

(3) Turn off the plasma discharge for deposition, pass clean compressed air or inert gas to return to normal pressure, open the cavity, and take out the substrate.
The method for preparing a nano-coating according to claim 5, wherein the monomer vapor includes monomer 1 and monomer 2;

The monomer 1 and the monomer 2 respectively lead into the reaction chamber;

Or, the monomer 1 and the monomer 2 are simultaneously led into the reaction chamber;

Alternatively, one of the monomer 1 and the monomer 2 is firstly introduced into the reaction chamber, and then the monomer 1 and the monomer 2 are simultaneously introduced.
The method for preparing a nano-coating according to claim 5, wherein the monomer 1 and / or the monomer 2 are atomized and volatilized by a feed pump to form the monomer vapor.
The method for preparing a nano-coating according to claim 5, wherein the plasma source gas in step (2) may be one or a mixture of several of helium, argon, nitrogen and hydrogen .
The method for preparing a nano-coating according to claim 5, wherein the volume of the reaction chamber of the plasma chamber is 1L-5000L, the gas flow rate of the plasma source is 5-1000sccm, and the monomer vapor passes into the reaction chamber The flow rate in the body is 1-2000 μL / min.
The method for preparing a nano-coating according to claim 5, wherein in the step (2), after passing the plasma source gas and before the plasma discharge for deposition, the method further includes The substrate is subjected to a plasma discharge process for pretreatment.
The method for preparing a nano-coating according to claim 10, characterized in that, in the step (2), the power of the plasma discharge for pretreatment is 2-500 W, and the continuous discharge time is 1-5400 s.
The method for preparing a nano-coating according to claim 5, wherein in the step (2), the power of the plasma discharge for deposition is 2-500W, and the continuous discharge time is 600-20000s.
The method for preparing a nano-coating according to claim 5 or 10, wherein the plasma discharge method is radio frequency discharge, microwave discharge, intermediate frequency discharge, penning discharge or electric spark discharge.
The method for preparing a nano-coating according to claim 5 or 10, wherein the plasma discharge method is radio frequency discharge, and the energy output method for controlling plasma radio frequency during radio frequency discharge is pulse or continuous output; plasma When the RF energy output method is pulse output, the pulse width is 10μs-50ms and the repetition frequency is 20Hz-10kHz.