(1) adding 25% of silica sol into a reaction kettle by mass percent, stirring and heating to 60 ℃, dripping 25% of 3- (methacryloyloxy) propyl trimethoxy silane while stirring, and preserving heat for 1 hour to prepare modified silica sol liquid;

(2) and (2) adding 10% of pentaerythritol triacrylate and 40% of high-functionality aliphatic urethane acrylate into a reaction kettle, stirring and heating to 60 ℃, adding the modified silica sol liquid prepared in the step (1) under stirring, and keeping the temperature for 1h to obtain the organic-inorganic hybrid resin.

Preferably, the stirring speed in the step (1) is 400 r/min; the stirring speed in the step (2) is 600 r/min.

Preferably, the silica sol used in the step (1) is a ZS-30 silica sol; the high-functionality aliphatic polyurethane acrylate used in the step (2) is hexa-functionality aliphatic polyurethane acrylate.

Preferably, the high-functionality urethane acrylate is an aliphatic urethane acrylate having a functionality of 9 to 15.

Preferably, the reactive monomer has a functionality greater than two.

Preferably, the active monomer is one or more of trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), pentaerythritol tri-acrylate, tetra-acrylate (PET3A) and dipentaerythritol hexaacrylate (DPHA); the photoinitiator is one or more of a cracking type photoinitiator, a hydrogen abstraction type photoinitiator or acyl phosphine oxide; the auxiliary agent is one or more of acrylate, polyester modified organic siloxane and polyether modified organic siloxane.

Preferably, the boiling point of the solvent is 100-140 ℃.

Preferably, the solvent is one or more selected from Ethyl Acetate (EAC), isobutyl isobutyrate (IBIB), isopropyl alcohol (IPA), isobutyl alcohol (IBA), Butyl Acetate (BAC), propylene glycol methyl ether acetate (PMA), and propylene glycol methyl ether (PM).

A preparation method of UV-cured ultrasonic spraying hardening liquid comprises the following steps: under the environment of completely isolating ultraviolet light by using a yellow light lamp, mixing an active monomer, a photoinitiator and a solvent, stirring at the speed of 200r/min until the active monomer, the photoinitiator and the solvent are dissolved, sequentially adding an inorganic-inorganic hybrid resin, high-functionality polyurethane acrylate and an auxiliary agent after the active monomer, the photoinitiator and the solvent are dissolved, and then stirring at the speed of 800r/min for 20min until the active monomer, the photoinitiator and the solvent are completely dissolved to prepare the UV-cured ultrasonic spraying hardening liquid.

The invention has the following beneficial effects:

(1) the UV-cured ultrasonic spraying hardening liquid takes organic-inorganic hybrid resin and high-functionality polyurethane acrylate as main resin, the viscosity of the hardening liquid is low, the hardening liquid can be used for continuous atomization spraying of a microporous ultrasonic atomization sheet to generate uniform liquid drops with small particle size, and a film obtained by spraying is high in hardness and good in wear resistance, so that the hardening liquid is very suitable for production of mobile phone backboards;

(2) the hardening liquid can be used for ultrasonic spraying, the ultrasonic spraying is to atomize the liquid into small liquid with the particle size of 20-80 microns by utilizing a micropore ultrasonic atomization sheet through high-frequency oscillation, because the atomized particles are fine and the surface activity of the particles is higher, the small liquid particles can be well adsorbed on the surface of a sprayed object, because the spraying is airless, the coating can not generate rebound and splash loss, the spraying uniformity can be effectively ensured, the oil accumulation and the thick edge can not be generated, meanwhile, the recycling can be realized, the discharge of VOC is reduced, and the ultrasonic spraying is efficient and environment-friendly;

(3) the auxiliary agent is selected from acrylate, polyester modified organic siloxane and polyether modified organic siloxane, the compatibility of the organic-inorganic hybrid resin is improved, and simultaneously the performance of the organic-inorganic hybrid resin is not influenced too much, and compared with the common auxiliary agent, a coating film obtained by adopting the auxiliary agent has better wear resistance;

(4) the boiling point of the solvent is 100-140 ℃, so that the drying speed of the hardening liquid is moderate, the ultrasonic spraying equipment cannot be blocked due to the excessively high drying speed, and the paint film after spraying cannot be edged due to the excessively high boiling point and no volatilization gradient, so that the attractiveness is seriously affected.

Detailed Description

The present invention will now be described in further detail with reference to examples.

The organic-inorganic hybrid resin adopts self-made resin with the mark of WS-870; the silica sol used in the step (1) for preparing the organic-inorganic hybrid resin is ZS-30 silica sol of Zhejiang Uuda chemical Co., Ltd, and the high-functionality aliphatic polyurethane acrylate used in the step (2) for preparing the organic-inorganic hybrid resin is 6145-100 of Changxing chemistry; the high-functionality polyurethane acrylate is one or more of UA-1730 of Zhongshanjieda, HM-5015 of Jiangxi Kunlong and L-6902 of sanchi chemical industry.

Preparation of organic-inorganic hybrid resin:

(1) adding 25kg of ZS-30 silica sol into a reaction kettle, stirring and heating to 60 ℃, dripping 25kg of 3- (methacryloyloxy) propyl trimethoxy silane at the stirring speed of 400r/min, and preserving heat for 1h to prepare modified silica sol liquid;

(2) and (2) adding 10kg of pentaerythritol triacrylate (PETA) and 40kg of 6145-100-ketone in a reaction kettle, stirring and heating to 60 ℃, adding the modified silica sol liquid prepared in the step (1) at a stirring speed of 600r/min, and keeping the temperature for 1h to obtain the organic-inorganic hybrid resin.

The preparation method of the hardening liquid comprises the following steps: under the environment of completely isolating ultraviolet light by using a yellow light lamp, mixing an active monomer, a photoinitiator and a solvent, stirring at the speed of 200r/min until the active monomer, the photoinitiator and the solvent are dissolved, sequentially adding an inorganic-inorganic hybrid resin, high-functionality polyurethane acrylate and an auxiliary agent after the active monomer, the photoinitiator and the solvent are dissolved, and then stirring at the speed of 800r/min for 20min until the active monomer, the photoinitiator and the solvent are completely dissolved to prepare the UV-cured ultrasonic spraying hardening liquid.

Examples 1 to 7 and comparative examples 1 to 5 the amounts of the respective components for preparing the hardening liquid are shown in Table 1.

TABLE 1

The construction conditions of the hardening liquid are as follows: base material pretreatment (alcohol wiping oil removal, electrostatic dust removal) → ultrasonic spraying (film thickness 5-10 μm) → infrared leveling (50 ℃, leveling 3-5min) → UV curing (curing energy 500 mJ/cm)²-800mJ/cm²) → workpiece offline.

The hardening liquids prepared in examples 1 to 7 and comparative examples 1 to 5 were subjected to the performance test of the coatings obtained by ultrasonic spraying, and the test results are shown in Table 2.

TABLE 2

The specific test method for cold and heat cycle resistance comprises the following steps: room temperature → -40 ℃ ± 2 ℃ hold 4H → room temperature 1H → 80 ℃ ± 2 ℃ (RH 80 ± 5%) hold 4H → room temperature, which is one cycle, for a total of 6 cycles tested.

The boiling point of the solvent in comparative example 3 is too low, which causes the problem that the viscosity of the spray nozzle is slowly increased because the solvent is volatilized too fast in the spraying process under the condition of continuous construction, and the effective continuous spraying cannot be carried out after the long-time construction.

In comparative example 4, the boiling point of the solvent is too high, no volatilization gradient exists, and the paint film after spraying has edge accumulation, thus seriously affecting the beauty.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. The UV-cured ultrasonic spraying hardening liquid is characterized in that: the paint comprises the following components in percentage by mass:

25 to 35 percent of organic-inorganic hybrid resin

10 to 20 percent of high-functionality polyurethane acrylate

3 to 7 percent of active monomer

1 to 3 percent of photoinitiator

0.1 to 0.5 percent of auxiliary agent

The balance of solvent.

2. The UV-curable ultrasonic spray hardening liquid of claim 1, wherein: the preparation method of the organic-inorganic hybrid resin comprises the following steps:

3. The UV-curable ultrasonic spray hardening liquid according to claim 2, wherein: the stirring speed in the step (1) is 400 r/min; the stirring speed in the step (2) is 600 r/min.

4. The UV-curable ultrasonic spray hardening liquid according to claim 2, wherein: the silica sol used in the step (1) is ZS-30 silica sol; the high-functionality aliphatic polyurethane acrylate used in the step (2) is hexa-functionality aliphatic polyurethane acrylate.

5. The UV-curable ultrasonic spray hardening liquid of claim 1, wherein: the high-functionality polyurethane acrylate is aliphatic polyurethane acrylate with the functionality of 9-15.

6. The UV-curable ultrasonic spray hardening liquid of claim 1, wherein: the reactive monomer has a functionality greater than two.

7. The UV-curable ultrasonic spray hardening liquid of claim 1, wherein: the active monomer is one or more of trimethylolpropane triacrylate, pentaerythritol tri-acrylate, pentaerythritol tetra-acrylate and dipentaerythritol hexaacrylate; the photoinitiator is one or more of a cracking type photoinitiator, a hydrogen abstraction type photoinitiator or acyl phosphine oxide; the auxiliary agent is one or more of acrylate, polyester modified organic siloxane and polyether modified organic siloxane.

8. The UV-curable ultrasonic spray hardening liquid of claim 1, wherein: the boiling point of the solvent is 100-140 ℃.

9. The UV-curable ultrasonic spray hardening liquid of claim 1, wherein: the solvent is one or more of ethyl acetate, isobutyl isobutyrate, isopropanol, isobutanol, butyl acetate, propylene glycol methyl ether acetate and propylene glycol methyl ether.

10. A method of preparing a UV-curable ultrasonic spray hardening liquid according to any one of claims 1 to 9, characterized in that: the method comprises the following steps: under the environment of completely isolating ultraviolet light by using a yellow light lamp, mixing an active monomer, a photoinitiator and a solvent, stirring at the speed of 200r/min until the active monomer, the photoinitiator and the solvent are dissolved, sequentially adding an inorganic-inorganic hybrid resin, high-functionality polyurethane acrylate and an auxiliary agent after the active monomer, the photoinitiator and the solvent are dissolved, and then stirring at the speed of 800r/min for 20min until the active monomer, the photoinitiator and the solvent are completely dissolved to prepare the UV-cured ultrasonic spraying hardening liquid.