Polyurea UV curing resin, and preparation method and application thereof

Abstract

The invention provides a polyurea UV-cured resin and a preparation method and application thereof. The preparation method comprises the following steps: urea forming: adding polyaspartic acid ester resin and a diluent into a reaction kettle, starting stirring, dropwise adding an isocyanate monomer, and reacting at the temperature of 30-60 DEG C; an end-capping step: dropwise adding monohydroxy acrylate, and then controlling the temperature to 60-80 DEG C for reaction; then adding secondary amino siloxane resin and / or perfluoro-1-octanol, reacting at the temperature of 50-85 DEG C, and cooling to obtain low-viscosity polyurea UV curing resin; the reaction refining process is extremely easy to industrialize, and has obvious advantages compared with the existing non-organic silicon resin and polyurethane modified propylene UV resin; the polyurea UV curing resin is low-viscosity single-component resin, and is good in adhesive property, sufficient in mechanical property and temperature resistance, wide in applicability, good in insulativity and high in voltage puncture resistance.

Description

Technical Field

[0001] The invention relates to a polyurea UV curing resin, a preparation method and application thereof, and belongs to the technical field of functional coatings and preparation thereof. Background Art

[0002] To protect circuit boards and related equipment from environmental corrosion, conventional coatings require protective lacquers applied to the surface of the circuit boards. This also increases and prolongs the service life of the boards, ensuring safety and reliability. However, current issues with circuit board protective lacquers include poor curing, uneven coating, air bubbles, cracks, pinholes, color change, shedding and cracking, and decreased electrical performance. Solvent-based acrylic-based protective lacquers suffer from poor heat resistance, solvent volatilization, and poor solvent resistance. Polyurethane-based protective lacquers offer good solvent and low-temperature resistance, as well as some moisture and water resistance, but suffer from poor heat resistance, generally operating within 80°C, difficulty repairing, and a short operating time. Silicone-based protective lacquers, while offering excellent weather and solvent resistance, suffer from poor abrasion resistance, low mechanical strength, and poor adhesion.

[0003] To overcome the shortcomings of existing PCB protective coatings, the industry has begun exploring UV resin photocuring as an alternative to solvent-based coatings such as one-component acrylic coatings and two-component polyurethane coatings. However, conventional acrylic ester UV resins also have inherent drawbacks, including a hard and brittle coating film, poor impact resistance, chemical resistance, electrical properties, and temperature resistance. To address these issues, polyester polyether polyol-based polyurethane-modified UV resins are now commercially available for PCB protective coatings. While these address the film's hardness and brittleness, the high viscosity of the resins still presents issues such as drying bubbles, heat resistance, and pinholes. Prior art approaches utilize polyester polyol- or polycarbonate polyol-based polyurethane-modified acrylates modified with secondary aminosiloxanes to achieve both moisture and UV curing. While these resins significantly improve hardness and adhesion, their temperature resistance has been limited. Furthermore, the high viscosity of polyester polyol- or polycarbonate polyol-based polyurethanes necessitates the addition of diluents to reduce viscosity for coating application. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the first object of the present invention is to provide a polyurea UV curing resin, which is a low-viscosity single-component resin with good bonding properties, sufficient mechanical properties and temperature resistance, wide applicability, good insulation properties and high voltage puncture resistance.

[0005] A second object of the present invention is to provide a method for preparing the above-mentioned polyurea UV curing resin, wherein the reaction refinement process is extremely easy to industrialize and has obvious advantages over existing non-silicone resins and polyurethane-modified propylene UV resins;

[0006] The third object of the present invention is to use the above-mentioned polyurea UV curing resin as a functional coating for circuit boards to improve the anti-corrosion performance, environmental protection performance and construction efficiency of circuit board protective paint.

[0007] The first object of the present invention can be achieved by adopting the following technical solution: a polyurea UV curing resin, the chemical structure of the resin is shown in I:

[0008]

[0009] The second object of the present invention can be achieved by adopting the following technical solution: a method for preparing a polyurea UV curing resin, comprising:

[0010] Urea formation step: add polyaspartic acid ester resin and diluent into a reaction kettle, start stirring, add isocyanate monomer dropwise, and react at a temperature of 30-60°C;

[0011] End-capping step: Control the temperature below 60°C, add monohydroxy acrylate dropwise, and after completion, control the temperature to 60-80°C for reaction; then add secondary aminosiloxane resin and / or perfluoro-1-octanol, react at a temperature of 50-85°C, and cool to obtain a low-viscosity polyurea UV-curable resin.

[0012] Furthermore, in the urea formation step, the reaction time is 2-4 hours; in the end-capping step, monohydroxy acrylate is added dropwise, and after completion, the temperature is controlled to 60-80°C and the reaction is carried out for 6-24 hours; secondary aminosiloxane resin and / or perfluoro-1-octanol are added and the reaction is carried out at a temperature of 50-85°C for 1-14 hours.

[0013] Furthermore, the chemical structure of polyaspartic acid ester resin is shown in II:

[0014] Among them, a=1, 2, 3.

[0015] Furthermore, the polyaspartic acid ester resin is at least one of HMDA type polyaspartic acid ester resin, DMDC type polyaspartic acid ester resin, polyether type polyaspartic acid ester resin and trifunctional polyaspartic acid ester resin.

[0016] Furthermore, the isocyanate is at least one of hexamethylene diisocyanate, isophorone diisocyanate and dicyclohexylmethane diisocyanate.

[0017] Furthermore, the monohydroxy acrylate is at least one of hydroxyethyl methacrylate, hydroxypropyl methacrylate and pentaerythritol triacrylate.

[0018] Furthermore, the molar ratio of the polyaspartic acid ester resin, the isocyanate monomer, the monohydroxy acrylate, the secondary aminosiloxane resin and / or the perfluoro-1-octanol is 1:(2-3):(1-2):1.

[0019] Furthermore, in the end-capping step, perfluoro-1-octanol is added and the reaction is carried out at a temperature of 50-85° C. for 1-14 hours.

[0020] Furthermore, the reaction formula of the preparation method is shown in III:

[0021]

[0022] The third object of the present invention can be achieved by adopting the following technical solution: using a polyurea UV curing resin, and using the above polyurea UV curing resin to prepare a paint for a circuit board.

[0023] Furthermore, the polyurea UV curing resin is mixed with a photoinitiator and then allowed to stand for defoaming treatment to be used as a protective paint for circuit boards.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The polyurea UV curable resin of the present invention is a low-viscosity single-component resin. On the one hand, it can avoid the problems of poor curing, uneven coating, and bubbles caused by product viscosity problems, and on the other hand, it can avoid the product's excessive brittleness that causes poor wear resistance, low mechanical strength, and poor adhesion. It also has high voltage puncture resistance.

[0026] 2. The polyurea UV curing resin of the present invention has good bonding properties, sufficient mechanical properties and temperature resistance, wide applicability, good insulation properties and high voltage puncture resistance;

[0027] 3. The preparation method of the polyurea UV curing resin of the present invention uses a polyaspartic acid ester resin as a skeleton. The polyaspartic acid ester resin has low activity and strong reaction controllability, and the excellent three-proof properties of silicone and polyurea are incorporated into the structure. After the isocyanate reacts with the aspartic acid ester polyurea resin, a double bond is introduced through a monohydroxy acrylate. The reaction refinement process is extremely easy to industrialize, and has obvious advantages over existing non-silicone resins and polyurethane-modified propylene UV resins.

[0028] 4. The polyurea UV curing resin of the present invention can be used as a functional coating for circuit boards. After preparation, thin film coating can be achieved through a simple low-pressure sprayer or knife coating, thereby improving the anti-corrosion performance, environmental protection performance and construction efficiency of the circuit board protective paint, and promoting new developments in circuit board protective paint coating technology. DETAILED DESCRIPTION

[0029] Below, in conjunction with specific embodiments, the present invention is further described:

[0030] A method for preparing a polyurea UV curing resin comprises:

[0031] Urea formation step: add polyaspartic acid ester resin and diluent into a reaction kettle, start stirring, add isocyanate monomer dropwise, and react at a temperature of 30-60°C for 2-4 hours;

[0032] End-capping step: Control the temperature below 60°C, add monohydroxy acrylate dropwise, and after completion, control the temperature to 60-80°C and react for 6-24 hours; then add secondary aminosiloxane resin and / or perfluoro-1-octanol, react at a temperature of 50-85°C for 1-14 hours, and cool to obtain a low-viscosity polyurea UV-curable resin;

[0033] The reaction formula is shown in III:

[0034]

[0035] The molar ratio of the polyaspartic acid ester resin, the isocyanate monomer, the monohydroxy acrylate, the secondary aminosiloxane resin and / or the perfluoro-1-octanol is 1:(2-3):(1-2):1.

[0036] Among them, the chemical structure of polyaspartic acid ester resin is shown in II:

[0037] Wherein, a=1, 2, 3; namely, at least one of HMDA type polyaspartic acid ester resin, DMDC type polyaspartic acid ester resin, polyether type polyaspartic acid ester resin and trifunctional polyaspartic acid ester resin.

[0038] HMDA type polyaspartic acid ester resin, DMDC type polyaspartic acid ester resin, for example NH242, 252, 241; polyether polyaspartic acid ester resins such as NH262, NH282; trifunctional polyaspartic acid ester resin is for example NH330.

[0039] The isocyanate is at least one of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate (HMDI).

[0040] The monohydroxy acrylate is at least one of hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA) and pentaerythritol triacrylate (PETA), and its chemical formula is shown in IV:

[0041] n (number of acrylate double bonds) = 1,2.

[0042] Among them, the secondary aminosiloxane resin is, for example, At least one of NH344 and 355.

[0043] The obtained polyurea UV curing resin is mixed with a photoinitiator, and allowed to stand for defoaming treatment before being used as a protective paint for circuit boards.

[0044] By introducing double bonds and fluorocarbon side chains into monohydroxy acrylate, the coating has good temperature resistance and stain resistance. The strength and stability of its urea bond are better than those of the urethane bond, showing higher wear resistance, scratch resistance and high ductility, greatly reducing the molecular weight of the raw materials, so the resin viscosity is low and no additional acrylate monomer is required because no catalyst is required during the reaction process; the secondary aminosiloxane resin provides cross-linking points for the final product and improves the heat resistance; the introduction of perfluoro-1-octanol as a functional structural unit makes the target product anti-fouling, high temperature resistant and high electrical properties; the final product has high aging resistance and can be used to prepare a very ideal long-lasting protective paint.

[0045] Example 1:

[0046] A method for preparing a polyurea UV curing resin comprises:

[0047] Urea formation step: 120 g of 2000 molecular weight polyaspartic acid ester resin NH262, 55.4 g of polyaspartic acid ester resin NH242 and a diluent were added to a reactor, stirring was started, and 115.9 g of isophorone diisocyanate (IPDI) monomer was added dropwise over 2 h. The reaction was continued at 50°C for 2.5 h.

[0048] End-capping step: control the temperature below 60°C, add 11.3g of hydroxyethyl methacrylate (HEMA) dropwise, and after 1h of addition, control the temperature to 60-70°C and shade the reaction for 23h; control the temperature below 45°C, then add 30.5g of secondary aminosiloxane resin NH344 and 34.8g of perfluoro-1-octanol, and add dropwise for 0.5h, keep warm at 55°C for 1h, until the NCO content is lower than 0.05%; cool and discharge to obtain a low-viscosity polyurea UV-curing resin.

[0049] 95.9 g of polyurea UV curing resin, 3.5 g of photoinitiator TPO-L, 0.3 g of antioxidant 1010, and 0.3 g of antioxidant 168 were mixed evenly, allowed to stand for defoaming treatment, and used to obtain a paint.

[0050] Example 2:

[0051] A method for preparing a polyurea UV curing resin comprises:

[0052] Urea formation step: 55.4 g of polyaspartic acid ester resin NH242 and diluent were added to a reaction kettle, stirring was started, and 44 g of isophorone diisocyanate (IPDI) monomer was added dropwise over 2 h, and the mixture was reacted at 50 ° C for 2 h;

[0053] End-capping step: Control the temperature below 60°C and add 29.7g of pentaerythritol triacrylate (PETA) dropwise. After 1 hour of dropwise addition, control the temperature to 60-70°C and shade the reaction for 23 hours; then add 39.6g of perfluoro-1-octanol and keep the temperature at 70°C for 12 hours until the NCO content is less than 0.05%; then cool and discharge to obtain a low-viscosity polyurea UV-curable resin.

[0054] 95.9 g of polyurea UV curing resin, 3.5 g of photoinitiator TPO-L, 0.3 g of antioxidant 1010, and 0.3 g of antioxidant 168 were mixed evenly, allowed to stand for defoaming treatment, and used to obtain a paint.

[0055] Example 3:

[0056] A method for preparing a polyurea UV curing resin comprises:

[0057] Urea formation step: 58g of polyaspartic acid ester resin NH252 and diluent were added to a reactor, stirring was started, and 44g of isophorone diisocyanate (IPDI) monomer was added dropwise over 2h, and the mixture was reacted at 50°C for 2h;

[0058] End-capping step: Control the temperature below 60°C, add 39g of pentaerythritol triacrylate (PETA) and 16.9g of hydroxyethyl methacrylate (HEMA) dropwise, and after 1h of addition, control the temperature to 60-70°C and shade the reaction for 23h; then add 30.5g of secondary aminosiloxane resin NH344, and add dropwise for 0.5h, keep the temperature at 55°C and react for 23h until the NCO content is less than 0.05%; cool and discharge to obtain a low-viscosity polyurea UV-curable resin.

[0059] 95.9 g of polyurea UV curing resin, 3.5 g of photoinitiator TPO-L, 0.3 g of antioxidant 1010, and 0.3 g of antioxidant 168 were mixed evenly, allowed to stand for defoaming treatment, and used to obtain a paint.

[0060] Example 4:

[0061] A method for preparing a polyurea UV curing resin comprises:

[0062] Urea formation step: 60 g of 2000 molecular weight polyaspartic acid ester resin NH262 and diluent were added to a reaction kettle, stirring was started, and 57.8 g of isophorone diisocyanate (IPDI) monomer was added dropwise over 2 h, and the mixture was reacted at 50°C for 2 h;

[0063] End-capping step: Control the temperature below 60°C, add 17g of pentaerythritol triacrylate (PETA) dropwise, and after 1 hour of dropwise addition, control the temperature to 60-70°C and shade the reaction for 23 hours; then add 52g of perfluoro-1-octanol dropwise, and complete the addition over 0.5 hours. Keep the temperature at 70°C and react for 12 hours until the NCO content is less than 0.05%; cool and discharge to obtain a low-viscosity polyurea UV-curable resin.

[0064] 95.9 g of polyurea UV curing resin, 3.5 g of photoinitiator TPO-L, 0.3 g of antioxidant 1010, and 0.3 g of antioxidant 168 were mixed evenly, allowed to stand for defoaming treatment, and used to obtain a paint.

[0065] Example 5:

[0066] A method for preparing a polyurea UV curing resin comprises:

[0067] Urea formation step: 60 g of 2000 molecular weight polyaspartic acid ester resin NH262, 58 g of polyaspartic acid ester resin NH252 and diluent were added to a reactor, stirring was started, and 68.9 g of dicyclohexylmethane diisocyanate (HMDI) monomer was added dropwise over 2 h, and the mixture was reacted at 50°C for 2 h;

[0068] End-capping step: Control the temperature below 60°C, add 17g of hydroxyethyl methacrylate (HEMA) and 39g of pentaerythritol triacrylate (PETA) dropwise, and after 1 hour of addition, control the temperature to 60-70°C in the dark and react for 23 hours; then add 30.5g of secondary aminosiloxane resin NH344, add dropwise over 0.5 hours, keep the temperature at 70°C and react for 13 hours until the NCO content is less than 0.05%; cool and discharge to obtain a low-viscosity polyurea UV-curable resin.

[0069] 95.9 g of polyurea UV curing resin, 3.5 g of photoinitiator TPO-L, 0.3 g of antioxidant 1010, and 0.3 g of antioxidant 168 were mixed evenly, allowed to stand for defoaming treatment, and used to obtain a paint.

[0070] Example 6:

[0071] A method for preparing a polyurea UV curing resin comprises:

[0072] Urea formation step: 60 g of 2000 molecular weight polyaspartic acid ester resin NH262, 55.4 g of polyaspartic acid ester resin NH242 and diluent were added to a reactor, stirring was started, and 68.9 g of dicyclohexylmethane diisocyanate (HMDI) monomer was added dropwise over 2 h, and the mixture was reacted at 50°C for 2 h;

[0073] End-capping step: Control the temperature below 60°C, add 11.3g of hydroxyethyl methacrylate (HEMA) and 26g of pentaerythritol triacrylate (PETA) dropwise, and after 1 hour of addition, control the temperature to 60-70°C and shade the reaction for 23 hours; then add 34.5g of perfluoro-1-octanol dropwise, and complete the addition over 0.5 hours. Keep the temperature at 70°C and react for 12 hours until the NCO content is less than 0.05%; cool and discharge to obtain a low-viscosity polyurea UV-curable resin.

[0074] 95.9 g of polyurea UV curing resin, 3.5 g of photoinitiator TPO-L, 0.3 g of antioxidant 1010, and 0.3 g of antioxidant 168 were mixed evenly, allowed to stand for defoaming treatment, and used to obtain a paint.

[0075] Comparative Example 1:

[0076] Conventional thermosetting two-component three-proof resin on the market, plus curing agent, baked at 120℃ for 2h.

[0077] Comparative Example 2:

[0078] Conventional polyurethane-modified UV-curing resins on the market contain a certain amount of residual NCO.

[0079] Mix 95.9 g of resin, 3.5 g of photoinitiator TPO-L, 0.3 g of antioxidant 1010, and 0.3 g of antioxidant 168 evenly, let stand and defoam for later use.

[0080] Comparative Example 3:

[0081] There are special silane-modified polyurethane UV curing resins on the market, which contain a certain amount of siloxane groups.

[0082] Mix 95.9 g of resin, 3.5 g of photoinitiator TPO-L, 0.3 g of antioxidant 1010, and 0.3 g of antioxidant 168 evenly, let stand and defoam for later use.

[0083] Performance test: Coated on the circuit board, the coating thickness is 200μm, and the UV track curing machine is used for light curing, and the curing energy is 600-800mJ / cm 2 , Comparative Example 1 was baked at 120°C for 2h, and the paint film thickness was 200μm.

[0084] (1) Hardness: According to the standard GB / T 2411-2008 Plastics and hard rubber - Determination of indentation hardness (Shore hardness) using a durometer, the hardness of the UV-cured resin was tested using a D-type Shore durometer.

[0085] (2) Adhesion: The adhesion of the paint film is measured according to the standard "GB / T 9286-1998 Paint and varnish film cross-cut test".

[0086] (3) Abrasion resistance: The abrasion resistance of the paint film is determined according to the standard GBT 17635-2011 Paints and varnishes - Abrasion resistance test.

[0087] (4) Heat resistance: The abrasion resistance of the paint film is determined according to the standard GBT 1740-2007 Paints and varnishes - Heat resistance test.

[0088] (5) Voltage resistance: The voltage puncture resistance of the paint film is determined according to the standard "GB / T 1408.1-2006 Test method for electrical strength of insulating materials".

[0089] The results are shown in Table 1:

[0090] Table 1 Test results

[0091]

[0092] As shown in Table 1, Examples 2-6 all exhibited greater hardness than Comparative Examples 1-3, while also exhibiting superior adhesion to Comparative Examples 1-2. The resulting paint films exhibited high hardness and adhesion. The dielectric strength and voltage puncture resistance of Examples 1-6 were significantly greater than those of Comparative Examples 1-3. From a temperature resistance perspective, Examples 1, 2, 4, and 6 exhibited excellent thermal stability, with temperatures exceeding 200°C. Furthermore, Examples 1-6 all exhibited good wear resistance. Comparative Examples 1-6 demonstrate that the polyurea UV-curable resin produced using the methods and raw materials employed in the present invention exhibits greater hardness and adhesion than commercially available thermosetting two-component, three-component protective resins, non-silicone UV moisture-curable resins, and silicone-modified polyurethane UV moisture-curable resins produced using other methods. The grafted fluoroalkane in Examples 1-6 exhibited superior temperature resistance compared to non-silicone-added materials, and the polyurea structure exhibited superior wear resistance, adhesion, and voltage puncture resistance compared to non-polyurea structures.

[0093] Those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all of these changes and modifications should fall within the scope of protection of the claims of the present invention.

Claims

1. A polyurea UV curing resin, characterized in that: The chemical structural formula of the resin is shown in I:

2. A method for preparing a polyurea UV curing resin, characterized in that: include: Urea formation step: add polyaspartic acid ester resin and diluent into a reaction kettle, start stirring, add isocyanate monomer dropwise, and react at a temperature of 30-60°C; End-capping step: Control the temperature below 60°C, add monohydroxy acrylate dropwise, and after completion, control the temperature to 60-80°C for reaction; then add secondary aminosiloxane resin and / or perfluoro-1-octanol, react at a temperature of 50-85°C, and cool to obtain a low-viscosity polyurea UV-curable resin.

3. The method for preparing a polyurea UV curable resin according to claim 2, wherein: In the urea formation step, the reaction time is 2-4 hours; in the end-capping step, monohydroxy acrylate is added dropwise, and after completion, the temperature is controlled to 60-80°C and the reaction is carried out for 6-24 hours; secondary aminosiloxane resin and / or perfluoro-1-octanol are added and the reaction is carried out at a temperature of 50-85°C for 1-14 hours.

4. The method for preparing a polyurea UV curable resin according to claim 2, wherein: The chemical structural formula of the polyaspartic acid ester resin is shown in II: Among them, a=1, 2, 3.

5. The method for preparing a polyurea UV curable resin according to claim 2, wherein: The polyaspartic acid ester resin is at least one of HMDA type polyaspartic acid ester resin, DMDC type polyaspartic acid ester resin, polyether type polyaspartic acid ester resin and trifunctional polyaspartic acid ester resin.

6. The method for preparing a polyurea UV curable resin according to claim 2, wherein: The isocyanate is at least one of hexamethylene diisocyanate, isophorone diisocyanate and dicyclohexylmethane diisocyanate.

7. The method for preparing a polyurea UV curable resin according to claim 2, wherein: The monohydroxy acrylate is at least one of hydroxyethyl methacrylate, hydroxypropyl methacrylate and pentaerythritol triacrylate.

8. The method for preparing a polyurea UV curable resin according to claim 2, wherein: The molar ratio of the polyaspartic acid ester resin, isocyanate monomer, monohydroxy acrylate, secondary aminosiloxane resin and / or perfluoro-1-octanol is 1:(2-3):(1-2):

1.

9. The method for preparing a polyurea UV curable resin according to claim 1, wherein: The reaction formula of the preparation method is shown in III:

10. An application of a polyurea UV curing resin, characterized in that: The polyurea UV curing resin as claimed in claim 1 is used to prepare a paint for a circuit board.

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