A low migration photocurable ink and its processing technology

Abstract

The invention discloses a low migration photocurable ink and a processing technology thereof, and relates to the technical field of photocurable ink. The scheme adopts raw materials such as octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether, etc., and reacts under ultraviolet light to obtain a dihydroxysiloxane monomer, and then the dihydroxysiloxane monomer and toluene diisocyanate are used to modify and graft a photoinitiator, and a vinyl reaction group is introduced to obtain a polymerization photoinitiator, and then the dihydroxysiloxane monomer is used to participate in a polyurethane polymerization reaction, and hydroxyethyl acrylate is used to block to prepare a photocurable polyurethane emulsion, and components such as a pigment and a polymerization photoinitiator are added to obtain the photocurable ink; the photocurable ink not only has excellent water resistance, but also has improved adhesion and comprehensive performance of the ink, and in the ink, the migration ability of the photoinitiator is greatly reduced, and the practicality of the product is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of photocurable inks, in particular to a low migration photocurable ink and a processing technology thereof. Background Art

[0002] Ultraviolet (UV) curing refers to a process in which, under ultraviolet radiation conditions, the photosensitive substances in the system absorb energy within a certain range of wavelengths, are excited to produce photochemical reactions, and then decompose to produce active free radicals or cations, thereby initiating the polymerization, crosslinking and curing of prepolymers or active monomers in the system, causing the liquid phase system to crosslink and polymerize instantly. Photoinitiators are introduced into the light-curing system, but the migration of photoinitiators has always been a focus of research and development personnel.

[0003] In addition, in the prior art, silicone monomers or fluorine-containing groups are introduced to improve the water resistance of photocurable inks. However, the application of fluorine-containing groups has environmental issues, and the current comprehensive performance of inks still cannot meet the needs of consumers. Therefore, in response to this problem, the present application discloses a low migration photocurable ink and its processing technology. Summary of the invention

[0004] The object of the present invention is to provide a low migration photocurable ink and a processing technology thereof to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a processing technology of low migration photocurable ink, comprising the following steps: Step 1: Take toluene diisocyanate, heat it to 65-70°C under nitrogen environment, slowly add dihydroxy hexavinylsiloxane monomer dropwise for 1-2 hours, keep warm for reaction for 1-2 hours, then add photoinitiator 2959 and catalyst, react at 45-50°C in dark for 2-3 hours, separate and purify to obtain polymerization photoinitiator; Step 2: pre-dry the polyester polyol at 110-120°C for 8-10 hours, then mix the polyester polyol and toluene diisocyanate, keep the mixture in a water bath at 45-50°C for 30-40 minutes, add a catalyst, react for 2-3 hours, then add 2,2-dihydroxymethylpropionic acid and dihydroxysiloxane monomer, react for 3-4 hours at 60-65°C, cool to 40-45°C, add pentaerythritol diacrylate, heat to 60-65°C, keep the mixture for 2-3 hours, finally add hydroxyethyl acrylate for end-capping, neutralize with triethylamine for 20-30 minutes, emulsify and disperse with deionized water to obtain a polyurethane emulsion; Step 3: Mix the polyurethane emulsion, the pigment, and the polymerization photoinitiator, add the dispersant, the leveling agent, and the deionized water, stir for 30 to 40 minutes, and grind to a fineness of less than 10 μm to obtain the photocurable ink.

[0006] In a more optimized solution, in step 3, the amount of each component used is: in parts by mass, 20-25 parts of polyurethane emulsion, 5-10 parts of pigment, 1-2 parts of polymerization photoinitiator, 0.5-1 part of dispersant, 0.5-1 part of leveling agent, and 15-20 parts of deionized water.

[0007] In a more optimized solution, in step 2, the amount of each component used is: in parts by mass, 90-100 parts of polyester polyol, 30-40 parts of toluene diisocyanate, 15-20 parts of 2,2-dihydroxymethylpropionic acid, 8-12 parts of dihydroxysiloxane monomer, 3-4 parts of pentaerythritol diacrylate, and 6-8 parts of hydroxyethyl acrylate.

[0008] In a more optimized scheme, in step 1, the preparation steps of the dihydroxysiloxane monomer are: octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether and tetrahydrofuran are mixed, stirred until completely dissolved, reacted under ultraviolet light for 40 to 50 minutes, and after the reaction is completed, the solvent is spin-dried, separated and purified to obtain the dihydroxysiloxane monomer.

[0009] In a more optimized solution, the molar ratio of the octavinyl POSS monomer to 2-mercaptoethanol is 1:(2-2.1); the molar ratio of the octavinyl POSS monomer to dodecyl mercaptan is 1:(1-2.1); and the amount of benzoin dimethyl ether is 1-2wt% of the total mass of the octavinyl POSS monomer, 2-mercaptoethanol and dodecyl mercaptan.

[0010] According to a more optimized solution, in step 2, the catalyst is dibutyltin dilaurate, and the amount of the catalyst is 0.5-1.5wt% of the total mass of the polyester polyol and toluene diisocyanate; the solid content of the polyurethane emulsion is 40-50%.

[0011] According to a more optimized solution, in step 1, the molar ratio of the hydroxyl group of the dihydroxy hexavinyl siloxane monomer to the isocyanate group of toluene diisocyanate is 1:1; and the molar ratio of toluene diisocyanate to the photoinitiator 2959 is 1:(1-1.1).

[0012] In a more optimized solution, in step 1, the catalyst is dibutyltin dilaurate, and the amount used is 0.2~0.3wt% of the total mass of the system.

[0013] A more optimized solution is a low migration photocurable ink obtained by processing according to any of the processing techniques described above.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: The invention discloses a low migration photocurable ink and a processing technology thereof. The method comprises the following steps: using raw materials such as octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether, etc. to react under ultraviolet light to obtain a dihydroxysiloxane monomer; then using the dihydroxysiloxane monomer and toluene diisocyanate to modify and graft a photoinitiator, introducing a vinyl reactive group, thereby obtaining a polymerized photoinitiator; then using the dihydroxysiloxane monomer to participate in a polyurethane polymerization reaction, and performing end-capping with hydroxyethyl acrylate to prepare a photocurable polyurethane emulsion; adding a pigment and a polymerized photoinitiator to mix; adding a dispersant, a leveling agent and deionized water; stirring and grinding, and obtaining the photocurable ink; the photocurable ink not only has excellent water resistance, but also has improved adhesion and comprehensive performance of the ink; and in the ink, the migration ability of the photoinitiator is greatly reduced, and the practicability of the product is greatly improved.

[0015] In this scheme, octavinyl POSS monomer, 2-mercaptoethanol and dodecyl mercaptan are first used as reaction raw materials, and vinyl and mercapto groups are used for ultraviolet light click reaction, and benzoin dimethyl ether is used as a photoinitiator to obtain a dihydroxysiloxane monomer. The scheme stipulates that "the molar ratio of the octavinyl POSS monomer and 2-mercaptoethanol is 1: (2~2.1); the molar ratio of the octavinyl POSS monomer and dodecyl mercaptan is 1: (1~2.1)". Under this parameter, the system contains not only hydroxyl groups and vinyl groups, but also long-chain alkyl groups. The presence of hydroxyl groups can participate in the subsequent polyurethane polymerization reaction, and the presence of vinyl groups can promote the crosslinking density during photocuring.

[0016] On this basis, the scheme uses dihydroxysiloxane monomer and toluene diisocyanate as a bridge to graft photoinitiator 2959 onto the dihydroxysiloxane monomer to obtain a polymerized photoinitiator. The polymerized photoinitiator can participate in the polymerization reaction in the photocuring system, so the migration ability of the photoinitiator is greatly reduced. In addition, due to the presence of siloxane, the water resistance of the photocurable ink is improved, and the overall ink performance is also improved.

[0017] In addition, the scheme also uses dihydroxysiloxane monomers as polyurethane chain extension monomers, and utilizes polyester polyols, toluene diisocyanate, hydroxymethylpropionic acid, pentaerythritol diacrylate and other components to polymerize to generate hydroxyethyl acrylate-terminated polyurethane emulsions, which participate in the subsequent photocuring system. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In this embodiment, octavinyl POSS monomer was purchased from Aladdin (P102212); the polyester polyol model was POL-756T, Mn=2000; the dispersant was BYK-168, and the leveling agent was BYK-358.

[0020] Embodiment 1: A processing technology of low migration light curing ink comprises the following steps: Step 1: Take toluene diisocyanate, heat it to 65°C under nitrogen environment, slowly add dihydroxy hexavinyl siloxane monomer, the adding time is 2h, keep warm for 2h, then add photoinitiator 2959 and catalyst, react at 45°C in the dark for 3h, separate and purify to obtain polymerization photoinitiator; the molar ratio of hydroxyl group of dihydroxy hexavinyl siloxane monomer to isocyanate group of toluene diisocyanate is 1:1; the molar ratio of toluene diisocyanate to photoinitiator 2959 is 1:1.1. The catalyst is dibutyltin dilaurate, and the amount used is 0.25wt% of the total mass of the system.

[0021] The preparation steps of the dihydroxysiloxane monomer are as follows: octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether and tetrahydrofuran are mixed, stirred until completely dissolved, reacted under ultraviolet light for 40 minutes, and after the reaction is completed, the solvent is dried by spin drying, separated and purified to obtain the dihydroxysiloxane monomer.

[0022] The molar ratio of the octavinyl POSS monomer to 2-mercaptoethanol is 1:2.1; the molar ratio of the octavinyl POSS monomer to dodecyl mercaptan is 1:2.1; the amount of benzoin dimethyl ether is 2wt% of the total mass of the octavinyl POSS monomer, 2-mercaptoethanol and dodecyl mercaptan.

[0023] Step 2: Pre-dry the polyester polyol at 120°C for 8 hours, then mix the polyester polyol and toluene diisocyanate, keep the mixture in a water bath at 45°C for 40 minutes, add a catalyst, react for 2 hours, then add 2,2-dihydroxymethyl propionic acid and dihydroxysiloxane monomer, react for 4 hours at 60°C, cool to 45°C, add pentaerythritol diacrylate, heat to 60°C, keep the mixture for 3 hours, finally add hydroxyethyl acrylate for end-capping, neutralize with triethylamine for 30 minutes, emulsify and disperse with deionized water to obtain a polyurethane emulsion. The solid content of the polyurethane emulsion is 40%.

[0024] The amount of each component is: by mass, 100 parts of polyester polyol, 35 parts of toluene diisocyanate, 15 parts of 2,2-dimethylol propionic acid, 8 parts of dihydroxysiloxane monomer, 3 parts of pentaerythritol diacrylate, and 6 parts of hydroxyethyl acrylate. The catalyst is dibutyltin dilaurate, and the amount of the catalyst is 1wt% of the total mass of polyester polyol and toluene diisocyanate.

[0025] Step 3: Mix the polyurethane emulsion, the pigment, and the polymerization photoinitiator, add the dispersant, the leveling agent, and the deionized water, stir for 30 minutes, and grind until the fineness reaches less than 10 μm to obtain the photocurable ink.

[0026] The amount of each component used is: by mass, 24 parts of polyurethane emulsion, 5 parts of pigment, 1.5 parts of polymerization photoinitiator, 0.5 parts of dispersant, 0.5 parts of leveling agent, and 15 parts of deionized water. Embodiment 2: A processing technology of low migration light curing ink, comprising the following steps: Step 1: Take toluene diisocyanate, heat it to 70°C under nitrogen environment, slowly add dihydroxy hexavinyl siloxane monomer, the addition time is 2h, keep warm for reaction for 1.5h, then add photoinitiator 2959 and catalyst, react at 50°C in the dark for 2.5h, separate and purify to obtain polymerization photoinitiator; the molar ratio of hydroxyl group of dihydroxy hexavinyl siloxane monomer to isocyanate group of toluene diisocyanate is 1:1; the molar ratio of toluene diisocyanate to photoinitiator 2959 is 1:1.1. The catalyst is dibutyltin dilaurate, and the amount used is 0.25wt% of the total mass of the system.

[0027] The preparation steps of the dihydroxysiloxane monomer are as follows: octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether and tetrahydrofuran are mixed, stirred until completely dissolved, reacted under ultraviolet light for 40 minutes, and after the reaction is completed, the solvent is dried by spin drying, separated and purified to obtain the dihydroxysiloxane monomer.

[0028] The molar ratio of the octavinyl POSS monomer to 2-mercaptoethanol is 1:2.1; the molar ratio of the octavinyl POSS monomer to dodecyl mercaptan is 1:2.1; the amount of benzoin dimethyl ether is 2wt% of the total mass of the octavinyl POSS monomer, 2-mercaptoethanol and dodecyl mercaptan.

[0029] Step 2: Pre-dry the polyester polyol at 120°C for 8 hours, then mix the polyester polyol and toluene diisocyanate, keep the mixture in a water bath at 50°C for 35 minutes, add a catalyst, react for 2.5 hours, then add 2,2-dihydroxymethyl propionic acid and dihydroxysiloxane monomer, react for 3.5 hours at 65°C, cool to 45°C, add pentaerythritol diacrylate, heat to 65°C, keep the mixture for 2.5 hours, finally add hydroxyethyl acrylate for end-capping, neutralize with triethylamine for 30 minutes, and emulsify and disperse with deionized water to obtain a polyurethane emulsion. The solid content of the polyurethane emulsion is 40%.

[0030] The amount of each component is: by mass, 100 parts of polyester polyol, 35 parts of toluene diisocyanate, 15 parts of 2,2-dimethylol propionic acid, 10 parts of dihydroxysiloxane monomer, 3 parts of pentaerythritol diacrylate, and 6 parts of hydroxyethyl acrylate. The catalyst is dibutyltin dilaurate, and the amount of the catalyst is 1wt% of the total mass of polyester polyol and toluene diisocyanate.

[0031] Step 3: Mix the polyurethane emulsion, the pigment, and the polymerization photoinitiator, add the dispersant, the leveling agent, and the deionized water, stir for 30 minutes, and grind until the fineness reaches less than 10 μm to obtain the photocurable ink.

[0032] The amount of each component used is: by mass, 24 parts of polyurethane emulsion, 5 parts of pigment, 1.5 parts of polymerization photoinitiator, 0.5 parts of dispersant, 0.5 parts of leveling agent, and 15 parts of deionized water. Embodiment 3: A processing technology for low migration photocurable ink, comprising the following steps: Step 1: Take toluene diisocyanate, heat it to 70°C under nitrogen environment, slowly add dihydroxy hexavinyl siloxane monomer, the adding time is 2h, keep warm for 1h, then add photoinitiator 2959 and catalyst, react at 50°C in the dark for 2h, separate and purify to obtain polymerization photoinitiator; the molar ratio of hydroxyl group of dihydroxy hexavinyl siloxane monomer to isocyanate group of toluene diisocyanate is 1:1; the molar ratio of toluene diisocyanate to photoinitiator 2959 is 1:1.1. The catalyst is dibutyltin dilaurate, and the amount used is 0.25wt% of the total mass of the system.

[0033] The preparation steps of the dihydroxysiloxane monomer are as follows: octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether and tetrahydrofuran are mixed, stirred until completely dissolved, reacted under ultraviolet light for 40 minutes, and after the reaction is completed, the solvent is dried by spin drying, separated and purified to obtain the dihydroxysiloxane monomer.

[0034] The molar ratio of the octavinyl POSS monomer to 2-mercaptoethanol is 1:2.1; the molar ratio of the octavinyl POSS monomer to dodecyl mercaptan is 1:2.1; the amount of benzoin dimethyl ether is 2wt% of the total mass of the octavinyl POSS monomer, 2-mercaptoethanol and dodecyl mercaptan.

[0035] Step 2: Pre-dry the polyester polyol at 120°C for 8 hours, then mix the polyester polyol and toluene diisocyanate, keep the mixture in a water bath at 50°C for 30 minutes, add a catalyst, react for 3 hours, then add 2,2-dihydroxymethyl propionic acid and dihydroxysiloxane monomer, react for 3 hours at 65°C, cool to 45°C, add pentaerythritol diacrylate, heat to 65°C, keep the mixture for 2 hours, finally add hydroxyethyl acrylate for end-capping, neutralize with triethylamine for 30 minutes, emulsify and disperse with deionized water to obtain a polyurethane emulsion. The solid content of the polyurethane emulsion is 40%.

[0036] The amount of each component is: by mass, 100 parts of polyester polyol, 35 parts of toluene diisocyanate, 15 parts of 2,2-dimethylol propionic acid, 12 parts of dihydroxysiloxane monomer, 3 parts of pentaerythritol diacrylate, and 6 parts of hydroxyethyl acrylate. The catalyst is dibutyltin dilaurate, and the amount of the catalyst is 1wt% of the total mass of polyester polyol and toluene diisocyanate.

[0037] Step 3: Mix the polyurethane emulsion, the pigment, and the polymerization photoinitiator, add the dispersant, the leveling agent, and the deionized water, stir for 30 minutes, and grind until the fineness reaches less than 10 μm to obtain the photocurable ink.

[0038] The amount of each component used is: by mass, 24 parts of polyurethane emulsion, 5 parts of pigment, 1.5 parts of polymerization photoinitiator, 0.5 parts of dispersant, 0.5 parts of leveling agent, and 15 parts of deionized water. Comparative Example 1: Example 3 was used as the control group. In Comparative Example 1, dodecyl mercaptan was not introduced during the preparation of the dihydroxysiloxane monomer.

[0039] A processing technology for low migration light curing ink comprises the following steps: Step 1: Take toluene diisocyanate, heat it to 70°C under nitrogen environment, slowly add dihydroxy hexavinyl siloxane monomer, the adding time is 2h, keep warm for 1h, then add photoinitiator 2959 and catalyst, react at 50°C in the dark for 2h, separate and purify to obtain polymerization photoinitiator; the molar ratio of hydroxyl group of dihydroxy hexavinyl siloxane monomer to isocyanate group of toluene diisocyanate is 1:1; the molar ratio of toluene diisocyanate to photoinitiator 2959 is 1:1.1. The catalyst is dibutyltin dilaurate, and the amount used is 0.25wt% of the total mass of the system.

[0040] The preparation steps of the dihydroxysiloxane monomer are as follows: octavinyl POSS monomer, 2-mercaptoethanol, benzoin dimethyl ether and tetrahydrofuran are mixed, stirred until completely dissolved, reacted under ultraviolet light for 40 minutes, and after the reaction is completed, the solvent is dried by spin drying, separated and purified to obtain the dihydroxysiloxane monomer.

[0041] The molar ratio of the octavinyl POSS monomer to 2-mercaptoethanol is 1:2.1; the amount of the benzoin dimethyl ether is 2wt% of the total mass of the octavinyl POSS monomer and 2-mercaptoethanol.

[0042] Step 2: Pre-dry the polyester polyol at 120°C for 8 hours, then mix the polyester polyol and toluene diisocyanate, keep the mixture in a water bath at 50°C for 30 minutes, add a catalyst, react for 3 hours, then add 2,2-dihydroxymethyl propionic acid and dihydroxysiloxane monomer, react for 3 hours at 65°C, cool to 45°C, add pentaerythritol diacrylate, heat to 65°C, keep the mixture for 2 hours, finally add hydroxyethyl acrylate for end-capping, neutralize with triethylamine for 30 minutes, emulsify and disperse with deionized water to obtain a polyurethane emulsion. The solid content of the polyurethane emulsion is 40%.

[0043] The amount of each component is: by mass, 100 parts of polyester polyol, 35 parts of toluene diisocyanate, 15 parts of 2,2-dimethylol propionic acid, 12 parts of dihydroxysiloxane monomer, 3 parts of pentaerythritol diacrylate, and 6 parts of hydroxyethyl acrylate. The catalyst is dibutyltin dilaurate, and the amount of the catalyst is 1wt% of the total mass of polyester polyol and toluene diisocyanate.

[0044] Step 3: Mix the polyurethane emulsion, the pigment, and the polymerization photoinitiator, add the dispersant, the leveling agent, and the deionized water, stir for 30 minutes, and grind until the fineness reaches less than 10 μm to obtain the photocurable ink.

[0045] The amount of each component used is: by mass, 24 parts of polyurethane emulsion, 5 parts of pigment, 1.5 parts of polymerization photoinitiator, 0.5 parts of dispersant, 0.5 parts of leveling agent, and 15 parts of deionized water. Comparative Example 2: Example 3 was used as the control group, and conventional photoinitiator 2959 was used in Comparative Example 2.

[0046] A processing technology for low migration light curing ink comprises the following steps: Step 1: The preparation steps of the dihydroxysiloxane monomer are as follows: octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether and tetrahydrofuran are mixed, stirred until completely dissolved, reacted under ultraviolet light for 40 minutes, and after the reaction is completed, the solvent is spin-dried, separated and purified to obtain the dihydroxysiloxane monomer.

[0047] The molar ratio of the octavinyl POSS monomer to 2-mercaptoethanol is 1:2.1; the molar ratio of the octavinyl POSS monomer to dodecyl mercaptan is 1:2.1; the amount of benzoin dimethyl ether is 2wt% of the total mass of the octavinyl POSS monomer, 2-mercaptoethanol and dodecyl mercaptan.

[0048] Step 2: Pre-dry the polyester polyol at 120°C for 8 hours, then mix the polyester polyol and toluene diisocyanate, keep the mixture in a water bath at 50°C for 30 minutes, add a catalyst, react for 3 hours, then add 2,2-dihydroxymethyl propionic acid and dihydroxysiloxane monomer, react for 3 hours at 65°C, cool to 45°C, add pentaerythritol diacrylate, heat to 65°C, keep the mixture for 2 hours, finally add hydroxyethyl acrylate for end-capping, neutralize with triethylamine for 30 minutes, emulsify and disperse with deionized water to obtain a polyurethane emulsion. The solid content of the polyurethane emulsion is 40%.

[0049] The amount of each component is: by mass, 100 parts of polyester polyol, 35 parts of toluene diisocyanate, 15 parts of 2,2-dimethylol propionic acid, 12 parts of dihydroxysiloxane monomer, 3 parts of pentaerythritol diacrylate, and 6 parts of hydroxyethyl acrylate. The catalyst is dibutyltin dilaurate, and the amount of the catalyst is 1wt% of the total mass of polyester polyol and toluene diisocyanate.

[0050] Step 3: Mix the polyurethane emulsion, the pigment, and the photoinitiator 2959, add the dispersant, the leveling agent, and the deionized water, stir for 30 minutes, and grind to a fineness of less than 10 μm to obtain the photocurable ink.

[0051] The amount of each component is: by mass, 24 parts of polyurethane emulsion, 5 parts of pigment, 29591.5 parts of photoinitiator, 0.5 parts of dispersant, 0.5 parts of leveling agent, and 15 parts of deionized water. Comparative Example 3: Example 3 was used as the control group, and the raw material for preparing the polymerization photoinitiator in Comparative Example 3 used 4-hydroxybutyl vinyl ether as the reaction monomer.

[0052] A processing technology for low migration light curing ink comprises the following steps: Step 1: Take toluene diisocyanate, heat to 45°C under nitrogen environment, slowly add 4-hydroxybutyl vinyl ether dropwise for 2 hours, keep warm in the dark for 1 hour, then add photoinitiator 2959 and catalyst, keep warm at 50°C for 2 hours, separate and purify to obtain polymerization photoinitiator; the molar ratio of hydroxyl group of 4-hydroxybutyl vinyl ether to isocyanate group of toluene diisocyanate is 1:1; the molar ratio of toluene diisocyanate to photoinitiator 2959 is 1:1.1. The catalyst is dibutyltin dilaurate, and the amount used is 0.25wt% of the total mass of the system.

[0053] Step 2: Pre-dry the polyester polyol at 120°C for 8 hours, then mix the polyester polyol and toluene diisocyanate, keep the mixture in a water bath at 50°C for 30 minutes, add a catalyst, react for 3 hours, then add 2,2-dihydroxymethyl propionic acid, react for 3 hours at 65°C, cool to 45°C, add pentaerythritol diacrylate, heat to 65°C, keep the mixture for 2 hours, finally add hydroxyethyl acrylate for end-capping, neutralize with triethylamine for 30 minutes, and emulsify and disperse with deionized water to obtain a polyurethane emulsion. The solid content of the polyurethane emulsion is 40%.

[0054] The amount of each component is: by mass, 100 parts of polyester polyol, 35 parts of toluene diisocyanate, 15 parts of 2,2-dimethylol propionic acid, 3 parts of pentaerythritol diacrylate, and 6 parts of hydroxyethyl acrylate. The catalyst is dibutyltin dilaurate, and the amount of the catalyst is 1wt% of the total mass of polyester polyol and toluene diisocyanate.

[0055] Step 3: Mix the polyurethane emulsion, the pigment, and the polymerization photoinitiator, add the dispersant, the leveling agent, and the deionized water, stir for 30 minutes, and grind until the fineness reaches less than 10 μm to obtain the photocurable ink.

[0056] The amount of each component used is: by mass, 24 parts of polyurethane emulsion, 5 parts of pigment, 1.5 parts of polymerization photoinitiator, 0.5 parts of dispersant, 0.5 parts of leveling agent, and 15 parts of deionized water.

[0057] Detection experiment: 1. The UV ink prepared in accordance with Examples 1 to 3 and Comparative Examples 1 to 3 was scraped on the surface of a PET film, dried at 80°C for 8 hours, cured with a UV lamp, and allowed to stand at 25°C for 24 hours after curing to obtain a printed sample, which was adhered to the surface of the printed sample using 3M tape. After repeated rolling three times, the tape was torn off with a uniform force, and its adhesion strength was calculated according to GB / T13217.7; the printed sample was cut into a size of 20 mm × 20 mm, immersed in deionized water for 24 hours, taken out to observe its color change, and the water absorption before and after the test was calculated.

[0058] 2. The printed samples prepared in Example 3 and Comparative Examples 1 to 3 were immersed in 200 mL of ethanol solution and migrated at 40° C. for 10 days. The concentration of the photoinitiator was then determined and calculated by the absorbance at 275 nm using ultraviolet spectroscopy.

[0059]

[0060] Conclusion: In this scheme, octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether and other raw materials are reacted under ultraviolet light to obtain dihydroxysiloxane monomer, and then the dihydroxysiloxane monomer and toluene diisocyanate are used to modify and graft the photoinitiator, and vinyl reactive groups are introduced to obtain a polymerized photoinitiator, and then the dihydroxysiloxane monomer is used to participate in the polyurethane polymerization reaction, and hydroxyethyl acrylate is used to cap the photocurable polyurethane emulsion, and a pigment and a polymerized photoinitiator are added to mix, and a dispersant, a leveling agent and deionized water are added, and the mixture is stirred and ground to obtain the photocurable ink; the photocurable ink not only has excellent water resistance, but also has improved adhesion and comprehensive performance of the ink, and in the ink, the migration ability of the photoinitiator is greatly reduced, and the practicality of the product is greatly improved.

[0061] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A processing technology for low migration light curing ink, characterized by: The following steps are involved: Step 1: Take toluene diisocyanate, heat it to 65-70°C under nitrogen environment, slowly add dihydroxy hexavinylsiloxane monomer dropwise for 1-2 hours, keep warm for reaction for 1-2 hours, then add photoinitiator 2959 and catalyst, react at 45-50°C in dark for 2-3 hours, separate and purify to obtain polymerization photoinitiator; Step 2: pre-dry the polyester polyol at 110-120°C for 8-10 hours, then mix the polyester polyol and toluene diisocyanate, keep the mixture in a water bath at 45-50°C for 30-40 minutes, add a catalyst, react for 2-3 hours, then add 2,2-dihydroxymethylpropionic acid and dihydroxysiloxane monomer, react for 3-4 hours at 60-65°C, cool to 40-45°C, add pentaerythritol diacrylate, heat to 60-65°C, keep the mixture for 2-3 hours, finally add hydroxyethyl acrylate for end-capping, neutralize with triethylamine for 20-30 minutes, emulsify and disperse with deionized water to obtain a polyurethane emulsion; Step 3: Mix the polyurethane emulsion, the pigment, and the polymerization photoinitiator, add the dispersant, the leveling agent, and the deionized water, stir for 30 to 40 minutes, and grind to a fineness of less than 10 μm to obtain the photocurable ink.

2. The processing technology of low migration photocurable ink according to claim 1, characterized in that: In step 3, the amount of each component is: by mass, 20-25 parts of polyurethane emulsion, 5-10 parts of pigment, 1-2 parts of polymerization photoinitiator, 0.5-1 part of dispersant, 0.5-1 part of leveling agent, and 15-20 parts of deionized water.

3. The processing technology of low migration photocurable ink according to claim 1, characterized in that: In step 2, the amount of each component is: in parts by mass, 90-100 parts of polyester polyol, 30-40 parts of toluene diisocyanate, 15-20 parts of 2,2-dihydroxymethylpropionic acid, 8-12 parts of dihydroxysiloxane monomer, 3-4 parts of pentaerythritol diacrylate, and 6-8 parts of hydroxyethyl acrylate.

4. The processing technology of low migration photocurable ink according to claim 1, characterized in that: In step 1, the preparation step of the dihydroxysiloxane monomer is: octavinyl POSS monomer, 2-mercaptoethanol, dodecyl mercaptan, benzoin dimethyl ether and tetrahydrofuran are mixed, stirred until completely dissolved, reacted under ultraviolet light for 40 to 50 minutes, and after the reaction is completed, the solvent is spin-dried, separated and purified to obtain the dihydroxysiloxane monomer.

5. The processing technology of low migration photocurable ink according to claim 4, characterized in that: The molar ratio of the octavinyl POSS monomer to 2-mercaptoethanol is 1:(2-2.1); the molar ratio of the octavinyl POSS monomer to dodecyl mercaptan is 1:(1-2.1); the amount of benzoin dimethyl ether is 1-2wt% of the total mass of the octavinyl POSS monomer, 2-mercaptoethanol and dodecyl mercaptan.

6. The processing technology of low migration photocurable ink according to claim 1, characterized in that: In step 2, the catalyst is dibutyltin dilaurate, and the amount of the catalyst is 0.5-1.5wt% of the total mass of the polyester polyol and toluene diisocyanate; the solid content of the polyurethane emulsion is 40-50%.

7. The processing technology of low migration photocurable ink according to claim 1, characterized in that: In step 1, the molar ratio of the hydroxyl group of the dihydroxy hexavinyl siloxane monomer to the isocyanate group of toluene diisocyanate is 1:1; the molar ratio of the toluene diisocyanate to the photoinitiator 2959 is 1:(1-1.1).

8. The processing technology of low migration photocurable ink according to claim 1, characterized in that: In step 1, the catalyst is dibutyltin dilaurate, and the amount used is 0.2-0.3 wt% of the total mass of the system.

9. A low migration photocurable ink obtained by the processing technology according to any one of claims 1 to 8.

Images