LED-UV gloss oil and preparation method thereof

Abstract

The invention discloses LED-UV (Light Emitting Diode-Ultraviolet) gloss oil and a preparation method thereof. The LED-UV gloss oil is prepared from the following raw materials: UV rosin resin, UV polyester resin, active amine, a light initiator, a stabilizer, a UV active monomer, nano silicon dioxide, polydimethylsiloxane, an ultraviolet light absorber and a de-foaming agent. When the LED-UV gloss oil is applied to printing, the curing speed, the coating hardness and the weather resistance are excellent, and the printing reliability can be ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of printing, and in particular relates to an LED-UV varnish and a preparation method thereof. Background Art

[0002] LED-UV varnish, also known as LED-UV curing ink, is a new material that has been widely used in the printing industry in recent years. Due to its fast curing speed, strong environmental protection, and compatibility with LED-UV light sources, LED-UV varnish has become an important innovation in the printing field. Traditional UV-curing inks typically rely on mercury arc lamps, but these light sources generate high heat and ozone, while LED-UV light sources are more energy-efficient and have less thermal impact on the substrate. However, existing LED-UV varnishes have shortcomings in curing speed, coating hardness, and weather resistance. Therefore, it is necessary to develop a new LED-UV varnish to further improve curing efficiency, improve ink film properties, and ensure its reliability during printing. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an LED-UV varnish and a preparation method thereof. The LED-UV varnish has excellent curing speed, coating hardness, and weather resistance when used in printing, ensuring reliability during printing.

[0004] The above technical objectives of the present invention are achieved through the following technical solutions:

[0005] Disclosed is an LED-UV varnish comprising the following raw materials: UV rosin resin, UV polyester resin, active amine, photoinitiator, stabilizer, UV active monomer, nano-silicon dioxide, polydimethylsiloxane, ultraviolet light absorber and defoamer.

[0006] In some embodiments of the present invention, the LED-UV varnish includes the following raw materials in parts by weight: UV rosin resin: 40-45 parts; UV polyester resin: 10-12 parts; active amine: 3-5 parts; photoinitiator: 8-10 parts; stabilizer: 1-2 parts; UV active monomer: 8-11 parts; nano-silica: 2-3 parts; polydimethylsiloxane: 0.5-1 part; ultraviolet light absorber: 0.3-0.8 parts; defoaming agent: 0.1-0.5 parts.

[0007] In some embodiments of the present invention, the UV rosin resin is at least one of Foralyn 5020-F and SYLVALITERE 110L.

[0008] In some embodiments of the present invention, the UV polyester resin is at least one of Rymer rj4267 and Changxing Chemical 6316 resin.

[0009] In some embodiments of the present invention, the active amine is at least one of oleamide and coconut diethanolamide.

[0010] In some embodiments of the present invention, the photoinitiator is at least one of a benzophenone photoinitiator or an acylphosphine oxide photoinitiator. A benzophenone photoinitiator refers to a compound having a benzophenone structure, specifically 2-hydroxy-2-methyl-1-phenyl-1-propanone or 2,2-dimethoxy-2-phenylacetophenone. A benzophenone photoinitiator refers to a compound having a benzophenone structure, specifically 2-hydroxy-2-methyl-1-phenyl-1-propanone or 2,2-dimethoxy-2-phenylacetophenone.

[0011] In some embodiments of the present invention, the stabilizer is tris(N-nitroso-N-phenylhydroxylamine)aluminum salt.

[0012] In some embodiments of the present invention, the UV active monomer is at least one of trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

[0013] In some embodiments of the present invention, the particle size of the nano-silica is 10-50nm. When the particle size of the nano-silica is in the range of 10-50nm, the dispersion of the particles in the varnish is significantly improved, forming a continuous and uniform network structure. This structure can effectively improve the transmission efficiency of ultraviolet energy during the curing process and shorten the time required for curing. At the same time, the interfacial bonding force between the nano-particles and the resin matrix is ​​enhanced, reducing the micro-crack defects inside the cured film layer, thereby improving the surface hardness and wear resistance of the coating. In addition, the dense barrier formed by the silica particles in this particle size range in the coating can hinder the penetration of external moisture and ultraviolet rays, thereby improving the weather resistance of the coating. The setting of the lower limit of the particle size of 10nm is to prevent the surface energy caused by the particles being too small from being too high and spontaneously aggregating, and the setting of the upper limit of the particle size of 50nm is to avoid the increase of the surface roughness of the coating and the decrease of the optical transparency due to the particles being too large.

[0014] In some embodiments of the present invention, the ultraviolet light absorber is a benzotriazole ultraviolet light absorber or a triazine ultraviolet light absorber. Benzotriazole ultraviolet light absorbers refer to organic compounds containing a benzotriazole ring structure, specifically 2-(2H-benzotriazole-2-yl)-4-methylphenol or 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol. Triazine ultraviolet light absorbers refer to compounds having a triazine ring structure, specifically 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-hexyloxyphenol or 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-(octyloxy)phenol.

[0015] In some embodiments of the present invention, the defoaming agent is a silicone defoaming agent, and the defoaming agent is one of BYK-141, BYK-066N and BYK-1799 defoaming agents.

[0016] A method for preparing the above-mentioned LED-UV varnish comprises the following steps: heating and mixing UV rosin resin and UV polyester resin, adding UV active monomer and stirring, then adding nano-silica and ultrasonically dispersing, cooling, adding active amine, photoinitiator, stabilizer, polydimethylsiloxane, ultraviolet absorber and defoamer, stirring and filtering to obtain the varnish.

[0017] In some embodiments of the present invention, the temperature after heating is 60-80°C, and the temperature after cooling is 40-50°C.

[0018] The beneficial effects of the present invention are:

[0019] (1) The UV rosin resin and UV polyester resin in the LED-UV varnish of the present invention form an interpenetrating network structure in a heated and molten state. The former provides a rigid skeleton to support the hardness of the coating, while the latter disperses stress through flexible segments to prevent cracking. The active amine and photoinitiator form an electron transfer system during the curing process, significantly shortening the free radical generation time. Nano-silica is evenly dispersed through hydrogen bonding between surface hydroxyl groups and the resin, and its high specific surface area enhances the scratch resistance of the coating. Polydimethylsiloxane migrates to the coating surface to form a low-energy interface, reducing the orange peel phenomenon during the coating process. The ultraviolet light absorber absorbs high-energy ultraviolet light through an intramolecular conjugated structure, inhibiting the photooxidative breakage of the resin main chain. The components are mixed in stages at a specific temperature to avoid premature decomposition of the photoinitiator and ensure a dynamic balance between the reactivity and stability of the system.

[0020] (2) Compared with the existing technology, traditional solutions mostly use a single resin, which leads to a contradiction between hardness and toughness, while the present invention achieves balanced performance by compounding resins; the existing photoinitiator system is difficult to effectively utilize LED narrow-spectrum light sources, and the present invention improves the energy conversion rate through the synergistic effect of amine co-initiators and photocatalysts. At the same time, conventional coatings lack long-term weathering protection, and this solution forms a dual protection mechanism through the composite effect of ultraviolet absorbers and nanofillers.

[0021] (3) The present invention achieves a significant improvement in curing speed, the surface hardness of the coating reaches a level that can resist mechanical scratching, and the color stability can still be maintained under outdoor ultraviolet irradiation. There are no bubbles or leveling defects on the surface of the printed product, which is suitable for packaging printing scenarios with high requirements for efficiency and durability.

[0022] (4) The LED-UV varnish curing reaction of the present invention can be completed within 3-10 seconds under the LED-UV light source, and the resulting coating has a pencil hardness of 3H. The color difference ΔE before and after 500 hours of QUV accelerated aging test is no more than 3.95, and the coating does not fall off or crack. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to specific embodiments.

[0024] Example 1:

[0025] Disclosed is an LED-UV varnish comprising the following raw materials in parts by weight: 40 parts of UV rosin resin; 10 parts of UV polyester resin; 3 parts of active amine; 8 parts of photoinitiator; 1 part of stabilizer; 8 parts of UV active monomer; 2 parts of nano-silicon dioxide; 0.5 parts of polydimethylsiloxane; 0.3 parts of ultraviolet light absorber; and 0.1 parts of defoaming agent. The UV rosin resin is Foralyn 5020-F, the UV polyester resin is Rymer rj4267 resin, the active amine is oleamide, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, the stabilizer is tris(N-nitroso-N-phenylhydroxylamine) aluminum salt, the UV active monomer is trimethylolpropane triacrylate, the particle size of nano-silica is 10 nm, the ultraviolet light absorber is 2-(2H-benzotriazole-2-yl)-4-methylphenol, and the defoamer is BYK-141.

[0026] A method for preparing the above-mentioned LED-UV varnish comprises the following steps: heating UV rosin resin and UV polyester resin to 60° C. and mixing them, adding UV active monomer and stirring evenly, then adding nano-silica and ultrasonically dispersing for 15 minutes, cooling to 40° C. and then adding active amine, photoinitiator, stabilizer, polydimethylsiloxane, ultraviolet absorber and defoamer, stirring evenly at high speed and filtering to obtain the varnish.

[0027] Example 2:

[0028] Disclosed is an LED-UV varnish comprising the following raw materials in parts by weight: 45 parts of UV rosin resin; 12 parts of UV polyester resin; 5 parts of active amine; 10 parts of photoinitiator; 2 parts of stabilizer; 11 parts of UV active monomer; 3 parts of nano-silicon dioxide; 1 part of polydimethylsiloxane; 0.8 parts of ultraviolet light absorber; and 0.5 parts of defoaming agent. The UV rosin resin is SYLVALITERE110L, the UV polyester resin is Changxing Chemical 6316 resin, the active amine is coconut oil diethanolamide, the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone, the stabilizer is tris(N-nitroso-N-phenylhydroxylamine) aluminum salt, the UV active monomer is dipentaerythritol hexaacrylate, the particle size of nano-silica is 50 nm, the ultraviolet light absorber is 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, and the defoaming agent is BYK-066N.

[0029] A method for preparing the above-mentioned LED-UV varnish comprises the following steps: heating UV rosin resin and UV polyester resin to 80° C. and mixing them, adding UV active monomer and stirring evenly, then adding nano-silica and ultrasonically dispersing for 15 minutes, cooling to 50° C. and then adding active amine, photoinitiator, stabilizer, polydimethylsiloxane, ultraviolet absorber and defoamer, stirring evenly at high speed and then filtering to obtain the varnish.

[0030] Example 3:

[0031] An LED-UV varnish comprises the following raw materials in parts by weight: 42 parts of UV rosin resin; 11 parts of UV polyester resin; 4 parts of active amine; 9 parts of photoinitiator; 1.5 parts of stabilizer; 10 parts of UV active monomer; 2.5 parts of nano-silicon dioxide; 0.8 parts of polydimethylsiloxane; 0.5 parts of ultraviolet light absorber; and 0.2 parts of defoaming agent. The UV rosin resin is SYLVALITERE110L, the UV polyester resin is Changxing Chemical 6316 resin, the active amine is coconut oil diethanolamide, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone, the stabilizer is tris(N-nitroso-N-phenylhydroxylamine) aluminum salt, the UV active monomer is dipentaerythritol hexaacrylate, the particle size of nano-silica is 30 nm, the ultraviolet light absorber is 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-hexyloxyphenol, and the defoaming agent is BYK-1799.

[0032] A method for preparing the above-mentioned LED-UV varnish comprises the following steps: heating UV rosin resin and UV polyester resin to 70° C. and mixing them, adding UV active monomer and stirring evenly, then adding nano-silica and ultrasonically dispersing for 15 minutes, cooling to 45° C. and then adding active amine, photoinitiator, stabilizer, polydimethylsiloxane, ultraviolet absorber and defoamer, stirring evenly at high speed and filtering to obtain the varnish.

[0033] Example 4:

[0034] An LED-UV varnish comprises the following raw materials in parts by weight: 43 parts of UV rosin resin; 10.5 parts of UV polyester resin; 3.5 parts of active amine; 8.5 parts of photoinitiator; 1.5 parts of stabilizer; 9 parts of UV active monomer; 2.3 parts of nano-silicon dioxide; 0.7 parts of polydimethylsiloxane; 0.6 parts of ultraviolet light absorber; and 0.3 parts of defoaming agent. The UV rosin resin is SYLVALITE RE110L, the UV polyester resin is Changxing Chemical 6316 resin, the active amine is coconut oil diethanolamide, the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone, the stabilizer is tris(N-nitroso-N-phenylhydroxylamine) aluminum salt, the UV active monomer is dipentaerythritol hexaacrylate, the particle size of nano-silica is 30 nm, the ultraviolet light absorber is 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-(octyloxy)phenol, and the defoamer is BYK-1799.

[0035] A method for preparing the above-mentioned LED-UV varnish comprises the following steps: heating UV rosin resin and UV polyester resin to 65° C. and mixing them, adding UV active monomer and stirring evenly, then adding nano-silica and ultrasonically dispersing for 15 minutes, cooling to 45° C. and then adding active amine, photoinitiator, stabilizer, polydimethylsiloxane, ultraviolet absorber and defoamer, stirring evenly at high speed and then filtering to obtain the varnish.

[0036] Comparative Example 1:

[0037] An LED-UV varnish is different from Example 3 only in that the raw materials do not contain UV rosin resin, and the remaining raw material ratios and preparation methods are exactly the same as those of Example 3.

[0038] Comparative Example 2:

[0039] An LED-UV varnish is different from Example 3 only in that the raw materials do not contain UV polyester resin, and the remaining raw material ratios and preparation methods are exactly the same as those of Example 3.

[0040] Comparative Example 3:

[0041] An LED-UV varnish is different from Example 3 only in that the raw materials do not contain nano-silicon dioxide, and the remaining raw material ratios and preparation methods are exactly the same as those of Example 3.

[0042] Comparative Example 4:

[0043] An LED-UV varnish is different from Example 3 only in that the raw materials do not contain polydimethylsiloxane, and the remaining raw material ratios and preparation methods are exactly the same as those of Example 3.

[0044] Test example:

[0045] The LED-UV varnishes of Examples 1-4 and Comparative Examples 1-4 were applied to the surface of the substrate and cured using LED-UV light to form a coating. The pencil hardness of the coating was tested, and the coating was subjected to an accelerated aging test in a UV aging tester in accordance with the standard GB / T16422.3-2022. The test conditions were: temperature: 70°C ± 5°C, relative humidity: 50% ± 5%, irradiation intensity: 600 W / m2, irradiation time: 500 h. The color difference ΔE of the coating before and after aging was tested, and the coating was observed for shedding or cracking. The test results are shown in Table 1.

[0046] Table 1. Coating performance test results

[0047]

[0048] As shown in Table 1, the coating formed after application of the LED-UV varnish of the present invention has a pencil hardness of 3H or higher. After accelerated aging testing, the color difference ΔE of the coating is no greater than 3.95, and the coating exhibits no shedding or cracking. This demonstrates that the LED-UV varnish of the present invention exhibits excellent coating hardness and weather resistance when applied to printing, ensuring reliability during printing. Furthermore, the LED-UV varnish of the present invention cures within 3-10 seconds under an LED-UV light source, exhibiting excellent curing speed and significantly improving curing efficiency.

[0049] In addition, by comparing Example 3 with Comparative Examples 1-4, it can be seen that, under the premise that other conditions remain unchanged, when the formula lacks one of UV rosin resin, UV polyester resin, nano-silica and polydimethylsiloxane, the hardness and weather resistance of the coating will decrease to varying degrees.

[0050] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. An LED-UV varnish, characterized by: The raw materials include: UV rosin resin, UV polyester resin, active amine, photoinitiator, stabilizer, UV active monomer, nano silicon dioxide, polydimethylsiloxane, ultraviolet light absorber and defoaming agent.

2. The LED-UV varnish according to claim 1, characterized in that: The raw materials include the following parts by weight: UV rosin resin: 40-45 parts; UV polyester resin: 10-12 parts; active amine: 3-5 parts; photocatalyst: 8-10 parts; Stabilizer: 1-2 parts; UV active monomer: 8-11 parts; Nano-silica: 2-3 parts; Polydimethylsiloxane: 0.5-1 part; UV absorber: 0.3-0.8 part; defoaming agent: 0.1-0.5 part.

3. The LED-UV varnish according to claim 1, characterized in that: The active amine is at least one of oleamide and coconut oil diethanolamide.

4. The LED-UV varnish according to claim 1, characterized in that: The photoinitiator is at least one of a benzophenone photoinitiator and an acylphosphine oxide photoinitiator.

5. The LED-UV varnish according to claim 1, characterized in that: The stabilizer is tris(N-nitroso-N-phenylhydroxylamine)aluminum salt.

6. The LED-UV varnish according to claim 1, characterized in that: The UV active monomer is at least one of trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

7. The LED-UV varnish according to claim 1, characterized in that: The particle size of the nano-silicon dioxide is 10-50 nm.

8. The LED-UV varnish according to claim 1, characterized in that: The ultraviolet light absorber is a benzotriazole ultraviolet light absorber or a triazine ultraviolet light absorber.

9. A method for preparing the LED-UV varnish according to any one of claims 1 to 8, characterized in that: The following steps are involved: Heat and mix UV rosin resin and UV polyester resin, add UV active monomer and stir, then add nano-silica and ultrasonically disperse, cool down and add active amine, photoinitiator, stabilizer, polydimethylsiloxane, ultraviolet light absorber and defoamer, stir and filter to obtain the product.

10. The method for preparing LED-UV varnish according to claim 9, characterized in that: The temperature after heating is 60-80°C, and the temperature after cooling is 40-50°C.

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