A single-material anti-yellowing freeze-drying ink and its preparation method

Abstract

This invention provides a single-material anti-yellowing freeze-drying surface printing ink, belonging to the field of surface printing inks and related technical fields. Its raw material composition includes the following components by weight percentage: 30%-40% silica-modified acrylic resin, 0.5%-1% leveling agent, 20%-30% color-retaining pigment, 0.5%-1.5% light stabilizer, 1%-2% antioxidant, and the balance being a mixed solvent. The single-material anti-yellowing freeze-drying surface printing ink of this invention has both excellent anti-yellowing and anti-freezing properties.

Description

Technical Field

[0001] This invention relates to the field of surface printing inks, specifically to a single-material anti-yellowing freeze-drying surface printing ink and its preparation method. Background Technology

[0002] Acrylic resins are single-material copolymers with characteristics such as light color, resistance to environmental corrosion, and easy adjustment. By selecting appropriate monomers, ink resins with excellent comprehensive performance and strong controllability can be obtained, which can better meet the current requirements of the printing industry for inks.

[0003] Most acrylic surface printing inks are prone to peeling and discoloration under freezing conditions, and have poor aging resistance and are prone to yellowing under the influence of light, heat and oxygen.

[0004] Therefore, it is necessary to research a new type of surface printing ink that can simultaneously resist yellowing and freezer damage. Summary of the Invention

[0005] The purpose of this invention is to provide a single-material anti-yellowing and anti-freezing surface printing ink and its preparation method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A single-material anti-yellowing freeze-drying surface printing ink comprises the following components by weight percentage: 30%–40% silica-modified acrylic resin, 0.5%–1% leveling agent, 20%–30% color-retaining pigment, 0.5%–1.5% light stabilizer, 1%–2% antioxidant, and the balance being a mixed solvent.

[0008] Preferably, the method for preparing the silica-modified acrylic resin is as follows:

[0009] S1: By weight, add 20-30 parts toluene and 3-5 parts nano-silica to the reactor, disperse evenly, then add 0.2-0.3 parts γ-aminopropylmethyldiethoxysilane, heat to 60-70℃ in a water bath, react for 6-8 hours, cool to room temperature, filter and wash to obtain aminated silica;

[0010] S2: Weigh 15-20 parts by weight of butyl acetate, 100 parts by weight of acrylic resin monomer, 0.5-1 parts by weight of n-dodecyl mercaptan and 3-5 parts by weight of tert-butyl peroxide. Under nitrogen protection, control the reaction temperature at 80-130℃, the stirring speed at 60-100 r / min, and the reaction time at 3-5 h to obtain the modified acrylic polymer.

[0011] S3: Add the aminated silica prepared in step S1 to the above modified acrylic polymer, stir evenly, and react at 40-60°C for 4-5 hours. After the reaction, remove the solvent by vacuum distillation to obtain silica-modified acrylic resin.

[0012] Preferably, the acrylic resin monomer is a mixture of benzyl methacrylate, butyl acrylate, dodecafluoroheptyl methacrylate and acrylic acid, in a mass ratio of 5:4-6:2-3:1-2.

[0013] Preferably, the method for preparing the color-retaining pigment is as follows:

[0014] A1: By weight, 20 parts of pigment base material and 1-2 parts of molybdenum disulfide powder are dispersed in ethanol, stirred evenly, and ammonia water is added to adjust the pH of the solution to 8-10 to obtain a pigment dispersion.

[0015] A2: Add 0.2 to 0.5 parts by weight of hydrophobic silane coupling agent to the pigment dispersion, stir at 60 to 70°C for 4 to 6 hours to obtain material A, and then perform solid-liquid separation and drying on material A to obtain color-retaining pigment.

[0016] Preferably, the pigment substrate is one or a mixture of at least two of the following: muscovite, azurite, malachite, malachite, and cinnabar; the particle size of the molybdenum disulfide powder is less than 20 micrometers; and the hydrophobic silane coupling agent is a mixture of butyltriethoxysilane and tridecafluorooctyltriethoxysilane, with a mass ratio of butyltriethoxysilane to tridecafluorooctyltriethoxysilane of 1:1.

[0017] Preferably, the leveling agent is BYK-390 leveling agent.

[0018] Preferably, the method for preparing the light stabilizer is as follows:

[0019] Weigh 1-2 parts of light stabilizer 770, 1-3 parts of phosphite, and 5-10 parts of ethanol by weight, mix and stir for 10-20 minutes to obtain the light stabilizer.

[0020] Preferably, the antioxidant is ascorbic acid.

[0021] Preferably, the mixed solvent is a mixture of ethanol, butyl acetate and ethylene glycol, wherein the mass ratio of ethanol, butyl acetate and ethylene glycol is 10:4 to 6:2 to 3.

[0022] This invention also provides a method for preparing the above-mentioned single-material anti-yellowing freeze-drying surface printing ink:

[0023] B1: Add silica-modified acrylic resin, mixed solvent and leveling agent to the reactor, heat and stir at 50°C to obtain a binder;

[0024] B2: Preheat the color-retaining pigment at 50°C for 10 minutes, then slowly add it to the binder prepared in B1. Stir until homogeneous to obtain the initial ink.

[0025] B3: Add antioxidants and light stabilizers to the primary ink and stir until a mixture is obtained;

[0026] B4: Grind the mixture obtained from B3 to a particle size of less than 10 micrometers to obtain the single-material anti-yellowing freeze-drying ink.

[0027] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0028] 1. The silica-modified acrylic resin provided by the present invention can improve the compatibility of the ink system, improve the dispersibility and tinting strength of the pigment, and make the color-retaining pigment uniformly dispersed in the resin matrix. The silica-modified acrylic resin and the color-retaining pigment work together to make the final ink have high resistance to yellowing and freezing.

[0029] 2. In the preparation of color-retaining pigments, surface treatment with hydrophobic silane coupling agents can reduce the moisture absorption of the pigment substrate and improve its freeze resistance. By adding molybdenum disulfide, the agglomeration and sedimentation of pigment powder can be prevented, enhancing the adhesion strength and color retention of the pigment, and improving the UV aging resistance of the ink.

[0030] 3. In the preparation of silica-modified acrylic resin, dodecafluoroheptyl methacrylate participates in the polymerization reaction. Its long side chains allow the fluorine atoms to fully extend, which can regulate the surface energy of the polymer and improve the compatibility between nano-silica and acrylic resins. Simultaneously, nano-silica facilitates the migration of fluorine atoms to the coating surface, improving the ink's anti-yellowing properties. Furthermore, dodecafluoroheptyl methacrylate enhances the hydrophobic properties of the system, achieving good water repellency and thus improving the ink's low-temperature freeze resistance. Detailed Implementation

[0031] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] The following leveling agents are all BYK-390 leveling agents manufactured by BYK in Germany, and the antioxidant is ascorbic acid.

[0033] Example 1:

[0034] A method for preparing a single-material anti-yellowing freeze-drying surface printing ink is as follows:

[0035] Raw material preparation: by weight percentage, 35% silica-modified acrylic resin, 0.7% leveling agent, 25% color-retaining pigment, 1% light stabilizer, 1.5% antioxidant, and the remainder is a mixed solvent.

[0036] B1: Add silica-modified acrylic resin, mixed solvent and leveling agent to the reactor, heat and stir at 50°C to obtain a binder;

[0037] B2: Preheat the color-retaining pigment at 50°C for 10 minutes, then slowly add it to the binder prepared in B1. Stir until homogeneous to obtain the initial ink.

[0038] B3: Antioxidants and light stabilizers added to the initial ink, mixed evenly at high speed;

[0039] B4: Grind the mixture obtained from B3 to a particle size of less than 10 micrometers to obtain the single-material anti-yellowing freeze-drying ink.

[0040] The preparation method of silica-modified acrylic resin is as follows:

[0041] S1: By weight, add 25 parts toluene and 4 parts nano silica to the reactor, disperse them evenly, then add 0.2 parts γ-aminopropylmethyldiethoxysilane, heat to 70°C in a water bath, react for 6 hours, cool to room temperature, filter and wash to obtain aminated silica.

[0042] S2: Weigh 15 parts by weight of butyl acetate, 100 parts by weight of acrylic resin monomer, 0.5 parts by weight of n-dodecyl mercaptan and 4 parts by weight of tert-butyl peroxide. Under nitrogen protection, control the reaction temperature at 90℃, the stirring speed at 80 r / min, and the reaction time at 4 h to obtain the modified acrylic polymer.

[0043] S3: Add the aminated silica prepared in step S1 to the modified acrylic polymer, stir evenly, and react at 50°C for 4.5 h. After the reaction, remove the solvent by vacuum distillation to obtain silica-modified acrylic resin.

[0044] The acrylic resin monomer is a mixture of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid, with a mass ratio of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid of 5:5:2:1.

[0045] The preparation method of the color-retaining pigment is as follows:

[0046] A1: By weight, 20 parts of pigment base material and 1.5 parts of molybdenum disulfide powder are dispersed in ethanol, stirred evenly, and ammonia water is added to adjust the pH of the solution to 9 to obtain a pigment dispersion.

[0047] A2: Add 0.3 parts by weight of hydrophobic silane coupling agent to the above pigment dispersion, stir at 65°C for 5 hours to obtain material A, and then perform solid-liquid separation and drying on material A to obtain color-retaining pigment.

[0048] The pigment substrate is muscovite.

[0049] The particle size of the molybdenum disulfide powder is less than 20 micrometers.

[0050] The hydrophobic silane coupling agent is a mixture of butyltriethoxysilane and tridecafluorooctyltriethoxysilane, with a mass ratio of butyltriethoxysilane to tridecafluorooctyltriethoxysilane of 1:1.

[0051] The light stabilizer is prepared by weighing 1.5 parts of light stabilizer 770, 2 parts of phosphite, and 7 parts of ethanol by weight, and stirring for 15 minutes to obtain the light stabilizer.

[0052] The mixed solvent is a mixture of ethanol, butyl acetate and ethylene glycol, with a mass ratio of ethanol, butyl acetate and ethylene glycol of 10:5:2.

[0053] Example 2:

[0054] A method for preparing a single-material anti-yellowing freeze-drying surface printing ink is as follows:

[0055] Raw material preparation: by weight percentage, 30% silica-modified acrylic resin, 0.5% leveling agent, 20% color-retaining pigment, 1% light stabilizer, 1% antioxidant, and the remainder is a mixed solvent.

[0056] B1: Add silica-modified acrylic resin, mixed solvent and leveling agent to the reactor, heat and stir at 50°C to obtain a binder;

[0057] B2: Preheat the color-retaining pigment at 50°C for 10 minutes, then slowly add it to the binder prepared in B1. Stir until homogeneous to obtain the initial ink.

[0058] B3: Add antioxidants and light stabilizers to the primary ink and stir at high speed to obtain a uniform mixture;

[0059] B4: Grind the mixture obtained from B3 to a particle size of less than 10 micrometers to obtain the single-material anti-yellowing freeze-drying ink.

[0060] The preparation method of silica-modified acrylic resin is as follows:

[0061] S1: By weight, add 20 parts toluene and 3 parts nano silica to the reactor, disperse them evenly, then add 0.25 parts γ-aminopropylmethyldiethoxysilane, heat to 60°C in a water bath, react for 6 hours, cool to room temperature, filter and wash to obtain aminated silica.

[0062] S2: Weigh 15 parts by weight of butyl acetate, 100 parts by weight of acrylic resin monomer, 0.5 parts by weight of n-dodecyl mercaptan and 4 parts by weight of tert-butyl peroxide. Under nitrogen protection, control the reaction temperature at 80℃, the stirring speed at 60 r / min, and the reaction time at 3 h to obtain the modified acrylic polymer.

[0063] S3: Add the aminated silica prepared in step S1 to the above modified acrylic polymer, stir evenly, and react at 40°C for 4 hours. After the reaction, remove the solvent by vacuum distillation to obtain silica-modified acrylic resin.

[0064] The acrylic resin monomer is a mixture of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid, with a mass ratio of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid of 5:5:2:1.

[0065] The method for preparing the color-retaining pigment is as follows:

[0066] A1: By weight, 20 parts of pigment base material and 1.5 parts of molybdenum disulfide powder are dispersed in ethanol, stirred evenly, and ammonia water is added to adjust the pH of the solution to 9 to obtain a pigment dispersion.

[0067] A2: Add 0.3 parts by weight of hydrophobic silane coupling agent to the above pigment dispersion, stir at 65°C for 5 hours to obtain material A, and then perform solid-liquid separation and drying on material A to obtain color-retaining pigment.

[0068] The pigment substrate is azurite.

[0069] The particle size of the molybdenum disulfide powder is less than 20 micrometers.

[0070] The hydrophobic silane coupling agent is a mixture of butyltriethoxysilane and tridecafluorooctyltriethoxysilane, with a mass ratio of butyltriethoxysilane to tridecafluorooctyltriethoxysilane of 1:1.

[0071] The light stabilizer is prepared by weighing 1 part of light stabilizer 770, 1 part of phosphite, and 5 parts of ethanol by weight, stirring for 10 minutes to obtain the light stabilizer.

[0072] The mixed solvent is a mixture of ethanol, butyl acetate and ethylene glycol, with a mass ratio of ethanol, butyl acetate and ethylene glycol of 10:5:2.

[0073] Example 3:

[0074] A method for preparing a single-material anti-yellowing freeze-drying surface printing ink is as follows:

[0075] Raw material preparation: by weight percentage, 40% silica-modified acrylic resin, 1% leveling agent, 25% color-retaining pigment, 1% light stabilizer, 2% antioxidant, and the remainder is a mixed solvent.

[0076] B1: Add silica-modified acrylic resin, mixed solvent and leveling agent to the reactor, heat and stir at 50°C to obtain a binder;

[0077] B2: Preheat the color-retaining pigment at 50°C for 10 minutes, then slowly add it to the binder prepared in B1. Stir until homogeneous to obtain the initial ink.

[0078] B3: Add antioxidants and light stabilizers to the primary ink and stir at high speed to obtain a uniform mixture;

[0079] B4: Grind the mixture obtained from B3 to a particle size of less than 10 micrometers to obtain the single-material anti-yellowing freeze-drying ink.

[0080] The preparation method of silica-modified acrylic resin is as follows:

[0081] S1: By weight, add 25 parts toluene and 4 parts nano silica to the reactor, disperse them evenly, then add 0.2 parts γ-aminopropylmethyldiethoxysilane, heat to 70°C in a water bath, react for 6 hours, cool to room temperature, filter and wash to obtain aminated silica.

[0082] S2: Weigh 15 parts by weight of butyl acetate, 100 parts by weight of acrylic resin monomer, 0.5 parts by weight of n-dodecyl mercaptan and 4 parts by weight of tert-butyl peroxide. Under nitrogen protection, control the reaction temperature at 90℃, the stirring speed at 80 r / min, and the reaction time at 4 h to obtain the modified acrylic polymer.

[0083] S3: Add the aminated silica prepared in step S1 to the above modified acrylic resin, stir evenly, and react at 50°C for 4.5 h. After the reaction, remove the solvent by vacuum distillation to obtain silica-modified acrylic resin.

[0084] The acrylic resin monomer is a mixture of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid, with a mass ratio of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid of 5:5:2:1.

[0085] The method for preparing the color-retaining pigment is as follows:

[0086] A1: By weight, 20 parts of pigment base material and 2 parts of molybdenum disulfide powder are dispersed in ethanol, stirred evenly, and ammonia water is added to adjust the pH of the solution to 9 to obtain a pigment dispersion.

[0087] A2: Add 0.3 parts by weight of hydrophobic silane coupling agent to the above pigment dispersion, stir at 65°C for 5 hours to obtain material A, and then perform solid-liquid separation and drying on material A to obtain color-retaining pigment.

[0088] The pigment substrate is malachite green.

[0089] The particle size of the molybdenum disulfide powder is less than 20 micrometers.

[0090] The hydrophobic silane coupling agent is a mixture of butyltriethoxysilane and tridecafluorooctyltriethoxysilane, with a mass ratio of butyltriethoxysilane to tridecafluorooctyltriethoxysilane of 1:1.

[0091] The light stabilizer is prepared by weighing 2 parts of light stabilizer 770, 3 parts of phosphite, and 10 parts of ethanol by weight, stirring for 20 minutes to obtain the light stabilizer.

[0092] The mixed solvent is a mixture of ethanol, butyl acetate and ethylene glycol, with a mass ratio of ethanol, butyl acetate and ethylene glycol of 10:5:2.

[0093] Example 4:

[0094] A method for preparing a single-material anti-yellowing freeze-drying surface printing ink is as follows:

[0095] Raw material preparation: by weight percentage, 33% silica-modified acrylic resin, 0.6% leveling agent, 27% color-retaining pigment, 0.6% light stabilizer, 1.3% antioxidant, and the remainder is a mixed solvent.

[0096] B1: Add silica-modified acrylic resin, mixed solvent and leveling agent to the reactor, heat and stir at 50°C to obtain a binder;

[0097] B2: Preheat the color-retaining pigment at 50°C for 10 minutes, then slowly add it to the binder prepared in B1. Stir until homogeneous to obtain the initial ink.

[0098] B3: Add antioxidants and light stabilizers to the primary ink and stir at high speed to obtain a uniform mixture;

[0099] B4: Grind the mixture obtained from B3 to a particle size of less than 10 micrometers to obtain the single-material anti-yellowing freeze-drying ink.

[0100] The preparation method of silica-modified acrylic resin is as follows:

[0101] S1: By weight, add 23 parts toluene and 4 parts nano silica to the reactor, disperse them evenly, then add 0.2 parts γ-aminopropylmethyldiethoxysilane, heat to 65°C in a water bath, react for 7 hours, cool to room temperature, filter and wash to obtain aminated silica.

[0102] S2: Weigh 16 parts by weight of butyl acetate, 100 parts by weight of acrylic resin monomer, 0.6 parts by weight of n-dodecyl mercaptan and 4 parts by weight of tert-butyl peroxide. Under nitrogen protection, control the reaction temperature at 100℃, the stirring speed at 70 r / min, and the reaction time at 4 h to obtain the modified acrylic polymer.

[0103] S3: Add the aminated silica prepared in step S1 to the above modified acrylic polymer, stir evenly, and react at 50°C for 4.5 h. After the reaction, remove the solvent by vacuum distillation to obtain silica-modified acrylic resin.

[0104] The acrylic resin monomer is a mixture of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid, with a mass ratio of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid of 5:5:2:1.

[0105] The method for preparing the color-retaining pigment is as follows:

[0106] A1: By weight, 20 parts of pigment base material and 1.3 parts of molybdenum disulfide powder are dispersed in ethanol, stirred evenly, and ammonia water is added to adjust the pH of the solution to 9 to obtain a pigment dispersion.

[0107] A2: Add 0.3 parts by weight of hydrophobic silane coupling agent to the above pigment dispersion, stir at 65°C for 5 hours to obtain material A, and then perform solid-liquid separation and drying on material A to obtain color-retaining pigment.

[0108] The pigment substrate is malachite.

[0109] The particle size of the molybdenum disulfide powder is less than 20 micrometers.

[0110] The hydrophobic silane coupling agent is a mixture of butyltriethoxysilane and tridecafluorooctyltriethoxysilane, with a mass ratio of butyltriethoxysilane to tridecafluorooctyltriethoxysilane of 1:1.

[0111] The light stabilizer is prepared by weighing 1.5 parts of light stabilizer 770, 1.5 parts of phosphite, and 6 parts of ethanol by weight, and stirring for 15 minutes to obtain the light stabilizer.

[0112] The mixed solvent is a mixture of ethanol, butyl acetate and ethylene glycol, with a mass ratio of ethanol, butyl acetate and ethylene glycol of 10:5:2.

[0113] Example 5:

[0114] A method for preparing a single-material anti-yellowing freeze-drying surface printing ink is as follows:

[0115] Raw material preparation: by weight percentage, 38% silica-modified acrylic resin, 0.8% leveling agent, 28% color-retaining pigment, 0.8% light stabilizer, 1.8% antioxidant, and the remainder is a mixed solvent.

[0116] B1: Add silica-modified acrylic resin, mixed solvent and leveling agent to the reactor, heat and stir at 50°C to obtain a binder;

[0117] B2: Preheat the color-retaining pigment at 50°C for 10 minutes, then slowly add it to the binder prepared in B1. Stir until homogeneous to obtain the initial ink.

[0118] B3: Add antioxidants and light stabilizers to the primary ink and stir at high speed to obtain a uniform mixture;

[0119] B4: Grind the mixture obtained from B3 to a particle size of less than 10 micrometers to obtain the single-material anti-yellowing freeze-drying ink.

[0120] The preparation method of silica-modified acrylic resin is as follows:

[0121] S1: By weight, add 28 parts toluene and 4 parts nano silica to the reactor, disperse them evenly, then add 0.2 parts γ-aminopropylmethyldiethoxysilane, heat to 65°C in a water bath, react for 6 hours, cool to room temperature, filter and wash to obtain aminated silica.

[0122] S2: Weigh 18 parts by weight of butyl acetate, 100 parts by weight of acrylic resin monomer, 0.8 parts by weight of n-dodecyl mercaptan and 4 parts by weight of tert-butyl peroxide. Under nitrogen protection, control the reaction temperature at 120℃, the stirring speed at 90 r / min, and the reaction time at 4 h to obtain the modified acrylic polymer.

[0123] S3: Add the aminated silica prepared in step S1 to the modified acrylic polymer, stir evenly, and react at 50°C for 4.5 h. After the reaction, remove the solvent by vacuum distillation to obtain silica-modified acrylic resin.

[0124] The acrylic resin monomer is a mixture of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid, with a mass ratio of benzyl methacrylate, butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid of 5:5:2:1.

[0125] The method for preparing the color-retaining pigment is as follows:

[0126] A1: By weight, 20 parts of pigment substrate and 1.8 parts of molybdenum disulfide powder are dispersed in ethanol, stirred evenly, and ammonia water is added to adjust the pH of the solution to 9 to obtain a pigment dispersion.

[0127] A2: Add 0.4 parts by weight of hydrophobic silane coupling agent to the above pigment dispersion, stir at 70°C for 5 hours to obtain material A, and then perform solid-liquid separation and drying on material A to obtain color-retaining pigment.

[0128] The pigment base material is cinnabar.

[0129] The particle size of the molybdenum disulfide powder is less than 20 micrometers.

[0130] The hydrophobic silane coupling agent is a mixture of butyltriethoxysilane and tridecafluorooctyltriethoxysilane, with a mass ratio of butyltriethoxysilane to tridecafluorooctyltriethoxysilane of 1:1.

[0131] The light stabilizer is prepared by weighing 1.8 parts by weight of light stabilizer 770, 2 parts by weight of phosphite, and 9 parts by weight of ethanol, stirring for 20 minutes to obtain the light stabilizer.

[0132] The mixed solvent is a mixture of ethanol, butyl acetate and ethylene glycol, with a mass ratio of ethanol, butyl acetate and ethylene glycol of 10:5:2.

[0133] Comparative Example 1:

[0134] The difference from Example 1 is that the color-retaining pigment is replaced with a pigment substrate, and the pigment substrate is selected as muscovite.

[0135] Comparative Example 2:

[0136] The difference from Example 1 is that in the preparation method of silica-modified acrylic resin, the acrylic resin monomer is a mixture of benzyl methacrylate, butyl acrylate and acrylic acid, and the mass ratio of benzyl methacrylate, butyl acrylate and acrylic acid is 7:5:1.

[0137] Comparative Example 3:

[0138] The difference from Example 1 is that in the preparation method of silica-modified acrylic resin, the acrylic resin monomer is a mixture of butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid, and the mass ratio of butyl acrylate, dodecyl fluoroheptyl methacrylate and acrylic acid is 10:2:1.

[0139] Comparative Example 4:

[0140] The difference from Example 1 is that the silica-modified acrylic resin is replaced with a modified acrylic polymer.

[0141] The preparation method of the modified acrylic polymer is as follows:

[0142] By weight, 15 parts of butyl acetate, 100 parts of acrylic resin monomer, 0.5 parts of n-dodecyl mercaptan and 4 parts of tert-butyl peroxide were weighed. Under nitrogen protection, the reaction temperature was controlled at 90℃, the stirring speed was 80 r / min, and the reaction time was 4 h to obtain the modified acrylic polymer.

[0143] Comparative Example 5:

[0144] The difference from Example 1 is that the color-retaining pigment is replaced with a pigment substrate, and the pigment substrate is selected as muscovite.

[0145] The silica-modified acrylic resin was replaced with a modified acrylic polymer.

[0146] The preparation method of the modified acrylic polymer is as follows:

[0147] By weight, 15 parts of butyl acetate, 100 parts of acrylic resin monomer, 0.5 parts of n-dodecyl mercaptan and 4 parts of tert-butyl peroxide were weighed. Under nitrogen protection, the reaction temperature was controlled at 90℃, the stirring speed was 80 r / min, and the reaction time was 4 h to obtain the modified acrylic polymer.

[0148] To verify the technical effects of the present invention, the above embodiments and comparative examples were compared and tested as follows.

[0149] The surface of the polyethylene substrate was subjected to corona treatment, cleaned, and dried. A 1mm × 1mm grid was then drawn on the polyethylene substrate. The surface printing inks prepared in the examples and comparative examples were used to print on the polyethylene substrate surface, forming ink layers. After photocuring and drying, printed samples were obtained. The following performance tests were performed, and the results are shown in Table 1.

[0150] Color difference value calculation: The printed samples were subjected to aging treatment and freezing treatment respectively. The ink on the surface of the printed substrate of the samples before and after treatment was measured with a colorimeter, and the color difference value ΔE was calculated. The smaller the ΔE, the stronger the resistance to yellowing.

[0151] Adhesion calculation: Printed samples underwent aging and freezing treatments respectively. Before and after each treatment, adhesive tape was evenly applied to the substrate of the printed sample, and the back of the tape was pressed with a finger to ensure even adhesion. Then, both ends of the tape were grasped and pulled up at the same speed, and the area of ​​ink that did not peel off on the substrate was recorded. The formula for ink adhesion is: Adhesion = Area of ​​ink that did not peel off after treatment / Area of ​​ink that did not peel off before treatment * 100%.

[0152] 1. Anti-yellowing performance: The printed sample was placed in a UV aging test chamber and aged continuously for 48 hours. The color difference and adhesion of the ink were calculated before and after the treatment.

[0153] 2. Freezing resistance: The printed sample was placed at -20 degrees Celsius and frozen for 72 hours. The samples before and after the treatment were measured, and the color difference and adhesion of the ink were calculated.

[0154] Table 1

[0155]

[0156] In Table 1, based on the color difference and adhesion values ​​of the surface printing inks in the anti-yellowing test of Examples 1 to 5, and the color difference and adhesion values ​​of the surface printing inks in the anti-freezing test of the surface printing inks, the surface printing inks of the present invention exhibit excellent anti-yellowing and anti-freezing properties.

[0157] The difference from Example 1 is that no color retention treatment was applied to the pigments in Comparative Example 1; the color difference value in the anti-yellowing test of the surface printing ink was 0.92, and the adhesion was 85%; the color difference value in the anti-freezing test of the surface printing ink was 0.77, and the adhesion was 78%. This indicates that molybdenum disulfide powder and hydrophobic silane coupling agent can affect the anti-yellowing and anti-freezing capabilities of the ink by influencing the color retention and anti-freezing properties of the pigments, and at the same time, they can further affect the surface adhesion strength of the ink by influencing the adhesion strength of the pigments.

[0158] The difference between Comparative Example 2 and Example 1 is that in the preparation method of the silica-modified acrylic resin, dodecafluoroheptyl methacrylate in the acrylic resin monomer is replaced with benzyl methacrylate. In the anti-yellowing test of the surface printing ink in Comparative Example 2, the color difference value was 1.14 and the adhesion was 72%; in the freeze resistance test of the surface printing ink in Comparative Example 2, the color difference value was 0.86 and the adhesion was 66%. This indicates that dodecafluoroheptyl methacrylate can improve the anti-yellowing and freeze resistance of surface printing inks.

[0159] The difference between Comparative Example 3 and Example 1 is that in the preparation method of the silica-modified acrylic resin, benzyl methacrylate in the acrylic resin monomer is replaced with butyl acrylate. In the anti-yellowing test of the surface printing ink in Comparative Example 3, the color difference value was 0.56 and the adhesion was 78%; in the freeze resistance test of the surface printing ink in Comparative Example 3, the color difference value was 0.49 and the adhesion was 70%. This indicates that the addition of benzyl methacrylate improves the anti-yellowing and freeze resistance of the surface printing ink.

[0160] The difference between Comparative Example 4 and Example 1 is that a modified acrylic polymer was directly used.

[0161] In the yellowing resistance test of the surface printing ink in Comparative Example 4, the color difference value was 1.06 and the adhesion was 77%; in the freeze resistance test of the surface printing ink in Comparative Example 4, the color difference value was 0.73 and the adhesion was 68%. This indicates that aminated silica improves the yellowing resistance and freeze resistance of the surface printing ink.

[0162] The difference between Comparative Example 5 and Example 1 is that the pigment is not subjected to color retention treatment, and a modified acrylic polymer is directly selected.

[0163] In the yellowing resistance test of the surface printing ink in Comparative Example 5, the color difference value was 1.44 and the adhesion was 66%; in the freeze resistance test of the surface printing ink in Comparative Example 5, the color difference value was 1.15 and the adhesion was 61%. This indicates that color-retaining pigments and aminated silica have a positive synergistic effect in improving the yellowing resistance and freeze resistance of surface printing inks.

[0164] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A single-material anti-yellowing freeze-drying surface printing ink, characterized in that: Its raw material composition includes the following components by weight percentage: 30% to 40% silica-modified acrylic resin, 0.5% to 1% leveling agent, 20% to 30% color-retaining pigment, 0.5% to 1.5% light stabilizer, 1% to 2% antioxidant, and the balance being a mixed solvent; The preparation method of the silica-modified acrylic resin is as follows: S1: By weight, add 20-30 parts toluene and 3-5 parts nano-silica to the reactor, disperse evenly, then add 0.2-0.3 parts γ-aminopropylmethyldiethoxysilane, heat to 60-70℃ under water bath conditions, react for 6-8 hours, cool to room temperature, filter and wash to obtain aminated silica; S2: Weigh 15-20 parts by weight of butyl acetate, 100 parts by weight of acrylic resin monomer, 0.5-1 parts by weight of n-dodecyl mercaptan and 3-5 parts by weight of tert-butyl peroxide. Under nitrogen protection, control the reaction temperature at 80-130℃, the stirring speed at 60-100 r / min, and the reaction time at 3-5 h to obtain the modified acrylic polymer. S3: Add the aminated silica prepared in step S1 to the above modified acrylic polymer, stir evenly, and react at 40-60°C for 4-5 hours. After the reaction, remove the solvent by vacuum distillation to obtain silica-modified acrylic resin. The acrylic resin monomer is a mixture of benzyl methacrylate, butyl acrylate, dodecafluoroheptyl methacrylate and acrylic acid, in a mass ratio of 5:4~6:2~3:1~2; The preparation method of the color-retaining pigment is as follows: A1: By weight, 20 parts of pigment base material and 1-2 parts of molybdenum disulfide powder are dispersed in ethanol, stirred evenly, and ammonia water is added to adjust the pH of the solution to 8-10 to obtain a pigment dispersion. A2: Add 0.2 to 0.5 parts by weight of hydrophobic silane coupling agent to the pigment dispersion, stir at 60 to 70°C for 4 to 6 hours to obtain material A, and then perform solid-liquid separation and drying on material A to obtain color-retaining pigment. The hydrophobic silane coupling agent is a mixture of butyltriethoxysilane and tridecafluorooctyltriethoxysilane, with a mass ratio of butyltriethoxysilane to tridecafluorooctyltriethoxysilane of 1:

1.

2. The single-material anti-yellowing freeze-drying surface printing ink according to claim 1, characterized in that: The pigment substrate is one or a mixture of at least two of the following: muscovite, azurite, malachite, malachite, and cinnabar; the particle size of the molybdenum disulfide powder is less than 20 micrometers.

3. The single-material anti-yellowing freeze-drying surface printing ink according to claim 1, characterized in that: The leveling agent is BYK-390 leveling agent.

4. The single-material anti-yellowing freeze-drying surface printing ink according to claim 1, characterized in that: The light stabilizer is prepared by weighing 1-2 parts of light stabilizer 770, 1-3 parts of phosphite, and 5-10 parts of ethanol by weight, mixing and stirring for 10-20 minutes to obtain the light stabilizer.

5. The single-material anti-yellowing freeze-drying surface printing ink according to claim 1, characterized in that: The antioxidant is ascorbic acid.

6. The single-material anti-yellowing freeze-drying surface printing ink according to claim 1, characterized in that: The mixed solvent is a mixture of ethanol, butyl acetate and ethylene glycol, with a mass ratio of ethanol, butyl acetate and ethylene glycol of 10:4 to 6:2 to 3.

7. A method for preparing a single-material anti-yellowing freeze-drying surface printing ink as described in any one of claims 1 to 6, characterized in that: Includes the following steps: B1: Add silica-modified acrylic resin, mixed solvent and leveling agent to the reactor, heat and stir at 50°C to obtain a binder; B2: Preheat the color-retaining pigment at 50°C for 10 minutes, then slowly add it to the binder prepared in B1. Stir until homogeneous to obtain the initial ink. B3: Add antioxidants and light stabilizers to the primary ink and stir until a mixture is obtained; B4: Grind the mixture obtained from B3 to a particle size of less than 10 micrometers to obtain the single-material anti-yellowing freeze-drying ink.

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