Environment-friendly ink for high-speed offset printing and preparation method thereof

Abstract

This invention provides an environmentally friendly ink for high-speed offset printing machines and its preparation method, relating to the field of inks. The environmentally friendly ink for high-speed offset printing machines comprises the following raw materials in parts by weight: 55-65 parts of conjugated copolymerized gum oil, 8-12 parts of high-boiling-point alkane solvent, 3-5 parts of soybean oil fatty acid methyl ester, 15-18 parts of pigment, 2-3.5 parts of silane-modified hollow ceramic microspheres, 3-5 parts of hydrophobically treated porous nano-silica, 0.5-1 part of polyethylene micro-powder wax, 0.3-0.6 parts of dispersant, and 0.1-0.3 parts of defoamer. This invention provides an environmentally friendly ink for high-speed offset printing machines and its preparation method, improving ink transfer rate and stability, and achieving stable and consistent printing quality.

Description

Technical Field

[0001] This invention relates to the field of inks, specifically to an environmentally friendly ink for high-speed offset printing machines and its preparation method. Background Technology

[0002] With the rapid development of the printing industry, high-speed offset printing presses have been widely used in various printing production processes due to their high efficiency and precision. Ink, as a key consumable in high-speed offset printing presses, directly determines print quality and production efficiency. Environmentally friendly inks for high-speed offset printing presses are specifically designed for high-speed offset printing processes. While meeting the performance requirements of high-speed printing, such as rapid drying, good transfer, and high resolution, they use environmentally friendly raw materials and formulations to reduce the content of harmful substances in the ink and minimize environmental pollution. These inks typically use vegetable oil-based or high-boiling-point solvents as binders, replacing traditional mineral oil-based binders, thereby reducing the emission of volatile organic compounds (VOCs).

[0003] To improve ink performance, various fillers, such as hollow ceramic microspheres and nano-silica, are typically added. However, the dispersibility and compatibility of these fillers in the ink system are often unsatisfactory. Hollow ceramic microspheres are usually hydrophilic, resulting in poor compatibility with non-polar components in the ink system and a tendency to aggregate, leading to uneven distribution and hindering their ability to reduce ink density and improve flowability. Porous nano-silica has a large number of hydrophilic silanol groups on its surface, which strongly adsorb polar components in the ink system, affecting not only ink flowability but also potentially causing an abnormally high elastic modulus, making the ink's rheological properties difficult to control. Furthermore, poor compatibility between the filler and the ink system can lead to problems such as stratification and sedimentation during storage, further affecting the ink's stability and lifespan. Based on this, the present invention provides an environmentally friendly ink for high-speed offset printing machines and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide an environmentally friendly ink for high-speed offset printing machines and its preparation method. The invention utilizes hydrophobically treated porous nano-silica to anchor the solvent and binder to form a stable three-dimensional network structure, preventing liquid separation and improving ink stability. It also constructs a rheological structure that balances high elastic modulus and moderate viscosity modulus, enabling the ink to spread quickly and evenly, preventing ink splatter, and improving the stability of printing quality.

[0005] On one hand, the present invention provides an environmentally friendly ink for high-speed offset printing machines and its preparation method, comprising the following raw materials in parts by weight: 55-65 parts of conjugated copolymerized gum oil, 8-12 parts of high-boiling-point alkane solvent, 3-5 parts of soybean oil fatty acid methyl ester, 15-18 parts of pigment, 2-3.5 parts of silane-modified hollow ceramic microspheres, 3-5 parts of hydrophobically treated porous nano-silica, 0.5-1 part of polyethylene micro powder wax, 0.3-0.6 parts of dispersant, and 0.1-0.3 parts of defoamer;

[0006] The conjugated copolymerized gum oil comprises the following raw materials in parts by weight: 10-25 parts of octylphenol rosin-modified phenolic resin, 10-25 parts of mixed phenol-modified rosin-modified phenolic resin, 10-30 parts of linseed oil, 10-30 parts of soybean oil, 0-1 parts of aluminum isooctanoate, and 1-5 parts of 2,6-di-tert-butyl-4-methylphenol.

[0007] Further, the conjugated copolymerized gum oil is prepared by the following method: octylphenol rosin-modified phenolic resin, mixed phenol-modified rosin-modified phenolic resin, drying vegetable oil, and semi-drying vegetable oil are mixed and heated to 200-230℃ under stirring to melt and react the resin for 1-1.5 hours; then the temperature is lowered to 100-140℃, 2,6-di-tert-butyl-4-methylphenol and aluminum isooctanoate are added, the temperature is raised to 160-165℃, and the temperature is maintained for 1-1.5 hours to obtain the final product.

[0008] Furthermore, the weight-average molecular weight M of the octylphenol rosin-modified phenolic resin and the mixed phenol-modified rosin-modified phenolic resin is... w The molecular weight ranges from 200,000 to 250,000, with a molecular weight distribution M. w / M n It is 3-10.

[0009] Furthermore, the preparation method of the silane-modified hollow ceramic microspheres includes: preheating the hollow ceramic microspheres to 75-85℃, preparing a silane hydrolysate in another container, hydrolyzing KH-570, ethanol, water and glacial acetic acid for 30-40 min, spraying the hydrolysate into the microspheres at a spray pressure of 0.4-0.6 MPa, a temperature of 75-85℃, high-speed mixing at 1100-1200 rpm for 40-50 min, drying at 110-120℃ for 2-3 h, and passing the mixture through a 400-mesh sieve to obtain the product.

[0010] Furthermore, the weight ratio of the hollow ceramic microspheres, KH-570, ethanol, water and glacial acetic acid is 100:3-4:250-350:10-20:0.4-0.6.

[0011] Furthermore, the preparation method of the hydrophobic treated porous nano silica includes: dispersing silica in toluene, ultrasonicating for 30-40 min, adding hexadecyltrimethoxysilane and ammonia, refluxing at 105-115℃ for 5-7 h, centrifuging, washing, drying, and then obtaining the product.

[0012] Furthermore, the mass concentration of the ammonia water is 20-30 wt%, and the weight ratio of the silicon dioxide, hexadecyltrimethoxysilane, toluene and ammonia water is 100:7-9:350-450:0.8-1.2.

[0013] Furthermore, the specific surface area of ​​the silicon dioxide is 320 m². 2 / g, pore size 4-6nm.

[0014] Furthermore, the high-boiling-point alkane solvent has a boiling range of 270-310℃ and an aromatic hydrocarbon content of <1%; the soybean oil fatty acid methyl ester has an iodine value of 130-135g I2 / 100g; the pigment is phthalocyanine blue 15:3; the dispersant is polyethylene glycol; and the defoamer is polydimethylsiloxane.

[0015] On the other hand, the present invention also provides a method for preparing an environmentally friendly ink for a high-speed offset printing machine, the steps of which include:

[0016] S1. Mix conjugated copolymerized gum oil, high-boiling-point alkane solvent, and soybean oil fatty acid methyl ester, and stir at 150-200℃ until homogenized; dry mix pigment, silane-modified hollow ceramic microspheres, hydrophobically treated porous nano silica and dispersant, and slowly add to the above mixture, and disperse under vacuum for 40-60 min.

[0017] S2. Transfer the pre-dispersed material to a three-roll mill for grinding until the fineness is ≤5μm;

[0018] S3. Cool the ground base ink to 35-40℃, add polyethylene micro powder wax and defoamer in sequence, stir for 60-90 minutes to mix evenly, and then cure at 35-40℃ for 24-36 hours.

[0019] S4. The cured ink is obtained by filtering it through a 400-mesh sieve.

[0020] The beneficial effects of this invention are as follows:

[0021] In this invention, silane-modified hollow ceramic microspheres, acting as lightweight and rigid hard spheres, play a unique role in the ink system. Their lightweight nature helps reduce the overall density of the ink, decreasing energy consumption during printing; their rigid structure provides structural support, ensuring the ink maintains a stable shape during printing. Simultaneously, this hard sphere structure generates a ball bearing effect, effectively improving ink flowability and allowing for smoother ink transfer between printed components, thus increasing the transfer rate. Meanwhile, hydrophobically treated porous nano-silica, as porous nanoparticles with a high specific surface area, possesses thickening and thixotropic properties. Its porous structure anchors solvents and binders, forming a stable three-dimensional network structure, preventing ink separation and ensuring ink stability. Furthermore, it can regulate the rheological properties of the ink, giving it both elasticity and appropriate viscosity during printing. The two work together to construct a rheological structure that balances the high elastic modulus (G') and moderate viscous modulus (G") required for high-speed offset printing, i.e., a suitable tgθ range. This rheological structure allows the ink to spread quickly and evenly during the printing process, achieving good ink distribution, while effectively preventing ink splatter and ensuring the stability and consistency of printing quality.

[0022] Hydrolytic spraying of hollow ceramic microspheres with silane coupling agents and hydrophobication treatment of porous nano-silica with long-chain alkyl silanes are key to ensuring good compatibility, uniform dispersion, and long-term stability of these two fillers with ink systems based on vegetable oil esters and high-boiling-point alkanes. The surface of hollow ceramic microspheres is originally hydrophilic, resulting in poor compatibility with ink systems. Through hydrolytic spraying of silane coupling agents, the silane coupling agents form reactive silanol groups after hydrolysis. These silanol groups can chemically react with the hydroxyl groups on the surface of the hollow ceramic microspheres, forming chemical bonds and creating a uniform hydrophobic graft layer on the microsphere surface. This hydrophobic graft layer alters the surface properties of the microspheres, changing them from hydrophilic to hydrophobic, thus improving compatibility with non-polar components in the ink system and achieving uniform dispersion. Simultaneously, this chemical bonding method strengthens the bond between the silane coupling agent and the microsphere surface, maintaining the stability of the microspheres in the ink system over a long period and preventing sedimentation or aggregation. Porous nano-silica, with its abundant hydrophilic silanol groups on its surface, strongly adsorbs polar components in the ink system, leading to an abnormally high elastic modulus (G') and poor flowability. By hydrophobizing with long-chain alkyl silanes, these alkyl silanes react with the silanol groups on the silica surface, introducing long-chain alkyl groups and reducing its surface energy. This significantly improves the dispersibility of the hydrophobically treated porous nano-silica in oil-based carriers, enabling uniform dispersion in the ink system and reducing agglomeration. Simultaneously, the introduction of long-chain alkyl groups can regulate the influence of porous nano-silica on the ink's rheological properties, ensuring it provides thickening and thixotropic effects without causing excessively high elastic modulus, thus guaranteeing good ink flowability and printability. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that the polyethylene micronized wax in this invention has a spherical structure, a softening point of 100-110℃, and an average particle size ≤7.5μm; polyethylene glycol Mn = 6000g / mol; polydimethylsiloxane CAS 9006-65-9, density 1 g / mL at 20℃, was purchased from Jinan Rongzheng Chemical Co., Ltd.; and silica has a specific surface area of ​​320 m². 2 / g, pore size 4-6 nm; hollow ceramic microspheres have a particle size D50 of 2.5-3.5 μm and a wall thickness of 0.1-0.3 μm.

[0025] Example 1

[0026] This embodiment provides an environmentally friendly ink for a high-speed offset printing machine, comprising the following raw materials in parts by weight:

[0027] The composition includes: 60 parts of conjugated copolymerized gum oil, 10 parts of high-boiling-point alkane solvent, 4 parts of soybean oil fatty acid methyl ester, 16.5 parts of pigment (phthalocyanine blue 15:3), 2.8 parts of silane-modified hollow ceramic microspheres, 4 parts of hydrophobically treated porous nano-silica, 0.8 parts of polyethylene micro powder wax, 0.45 parts of dispersant (polyethylene glycol), and 0.2 parts of defoamer (polydimethylsiloxane).

[0028] The preparation methods for conjugated copolymerized gum oils include:

[0029] Raw material ratio: 18 parts octylphenol rosin-modified phenolic resin, 17 parts mixed phenol-modified rosin-modified phenolic resin, 20 parts linseed oil, 22 parts soybean oil, 0.5 parts aluminum isooctanoate, and 3 parts 2,6-di-tert-butyl-4-methylphenol. The weight-average molecular weight (Mw) of the octylphenol rosin-modified phenolic resin and the mixed phenol-modified rosin-modified phenolic resin used is 230,000, and the molecular weight distribution (Mw / Mn) is 6.

[0030] Octylphenol rosin-modified phenolic resin, mixed phenol-modified rosin-modified phenolic resin, linseed oil, and soybean oil were added to a reaction vessel. The mixture was heated to 215°C under stirring to melt the resin and react for 1.2 hours. Then the temperature was lowered to 120°C, and 2,6-di-tert-butyl-4-methylphenol and aluminum isooctanoate were added. The temperature was then raised to 162°C and held for 1.2 hours. The product was then discharged to obtain the conjugated copolymerized gum oil.

[0031] The preparation methods of silane-modified hollow ceramic microspheres include:

[0032] Raw material ratio: 100 parts by weight of hollow ceramic microspheres, 3.5 parts by weight of KH-570 silane coupling agent, 300 parts by weight of ethanol, 15 parts by weight of deionized water, and 0.5 parts by weight of glacial acetic acid;

[0033] Hollow ceramic microspheres were preheated at 80°C. In another container, KH-570, ethanol, water, and glacial acetic acid were mixed and stirred for 35 min to prepare a silane hydrolysate. The hydrolysate was sprayed through an atomizing nozzle onto the preheated microspheres at 80°C and a spray pressure of 0.5 MPa, and mixed at high speed for 45 min. The treated material was dried at 115°C for 2.5 h and passed through a 400-mesh sieve to obtain silane-modified hollow ceramic microspheres.

[0034] The preparation methods for hydrophobically treated porous nano-silica include:

[0035] 100 parts by weight of silicon dioxide, 8 parts by weight of hexadecyltrimethoxysilane, 400 parts by weight of toluene, and 1.0 part by weight of ammonia solution with a mass concentration of 25%.

[0036] Silica was dispersed in toluene and sonicated for 35 min. Then, hexadecyltrimethoxysilane and ammonia were added, and the mixture was refluxed at 110 °C for 6 h. After the reaction was complete, the solid was separated by centrifugation, washed three times with toluene, and finally dried at 80 °C and -0.095 MPa vacuum for 8 h to obtain hydrophobically treated porous nano-silica.

[0037] Among them, the high-boiling-point alkane solvent has a boiling range of 270-310℃ and an aromatic content of <1%; the iodine value of soybean oil fatty acid methyl ester is 132 g I2 / 100g.

[0038] The method for preparing environmentally friendly ink for high-speed offset printing machines in this embodiment includes the following steps:

[0039] S1. Add 60 parts of conjugated copolymerized gum oil, 10 parts of high-boiling-point alkane solvent, and 4 parts of soybean oil fatty acid methyl ester to a stirred tank and stir at 150℃ and 400 rpm until completely homogenized; dry mix 16.5 parts of phthalocyanine blue 15:3 pigment, 2.8 parts of silane-modified hollow ceramic microspheres, 4 parts of hydrophobicated porous nano-silica, and 0.45 parts of polyethylene glycol dispersant evenly; slowly add this dry mixture to the homogenized mixture under stirring at 500 rpm; after the addition is complete, continue to disperse at high speed of 1500 rpm for 50 min under a vacuum of -0.08 MPa to obtain a pre-dispersed slurry;

[0040] S2. Transfer the pre-dispersed slurry obtained in S1 to a three-roll mill and perform multiple passes of fine grinding until the fineness of the sample is ≤5μm to obtain the base ink;

[0041] S3. Transfer the ground base ink to a conditioning kettle and cool it to 38°C; add 0.8 parts of polyethylene micro powder wax and 0.2 parts of polydimethylsiloxane defoamer in sequence; mix at a low speed of 200 rpm for 75 min, and then cure the ink at 38°C for 30 h.

[0042] S4. After the ink has matured, it is filtered through a 400-mesh stainless steel sieve to obtain the final product.

[0043] Example 2

[0044] This embodiment provides an environmentally friendly ink for a high-speed offset printing machine, comprising the following raw materials in parts by weight:

[0045] The composition includes 65 parts of conjugated copolymerized gum oil, 12 parts of high-boiling-point alkane solvent, 5 parts of soybean oil fatty acid methyl ester, 18 parts of pigment (phthalocyanine blue 15:3), 3.5 parts of silane-modified hollow ceramic microspheres, 5 parts of hydrophobically treated porous nano silica, 1 part of polyethylene micro powder wax, 0.6 parts of dispersant (polyethylene glycol), and 0.3 parts of defoamer (polydimethylsiloxane).

[0046] The preparation methods for conjugated copolymerized gum oils include:

[0047] Raw material ratio: 25 parts octylphenol rosin-modified phenolic resin, 10 parts mixed phenol-modified rosin-modified phenolic resin, 30 parts linseed oil, 10 parts soybean oil, 1 part aluminum isooctanoate, and 5 parts 2,6-di-tert-butyl-4-methylphenol. The weight-average molecular weight (Mw) of the octylphenol rosin-modified phenolic resin and the mixed phenol-modified rosin-modified phenolic resin used is 250,000, and the molecular weight distribution (Mw / Mn) is 10.

[0048] Octylphenol rosin-modified phenolic resin, mixed phenol-modified rosin-modified phenolic resin, linseed oil, and soybean oil were added to a reaction vessel. The mixture was heated to 230°C under stirring to melt the resin and react for 1 hour. Then the temperature was lowered to 140°C, and 2,6-di-tert-butyl-4-methylphenol and aluminum isooctanoate were added. The temperature was then raised to 165°C and held for 1 hour. The product was then discharged to obtain the conjugated copolymerized gum oil.

[0049] The preparation methods of silane-modified hollow ceramic microspheres include:

[0050] Raw material ratio: 100 parts by weight of hollow ceramic microspheres, 4 parts by weight of KH-570 silane coupling agent, 350 parts by weight of ethanol, 20 parts by weight of deionized water, and 0.6 parts by weight of glacial acetic acid.

[0051] Hollow ceramic microspheres were preheated at 85°C. In another container, KH-570, ethanol, water, and glacial acetic acid were mixed and stirred for 30 min to prepare a silane hydrolysate. The hydrolysate was sprayed through an atomizing nozzle onto the preheated microspheres at 85°C and a spray pressure of 0.6 MPa, and mixed at high speed for 40 min. The treated material was dried at 120°C for 2 h and passed through a 400-mesh sieve to obtain silane-modified hollow ceramic microspheres.

[0052] The preparation methods for hydrophobically treated porous nano-silica include:

[0053] 100 parts by weight of silicon dioxide, 9 parts by weight of hexadecyltrimethoxysilane, 450 parts by weight of toluene, and 1.2 parts by weight of ammonia solution with a mass concentration of 30 wt%.

[0054] Silica was dispersed in toluene and sonicated for 40 min. Then, hexadecyltrimethoxysilane and ammonia were added, and the mixture was refluxed at 115 °C for 5 h. After the reaction was complete, the solid was separated by centrifugation, washed three times with toluene, and finally dried at 80 °C and -0.095 MPa vacuum for 8 h to obtain hydrophobically treated porous nano-silica.

[0055] Among them, the high-boiling-point alkane solvent has a boiling range of 270-310℃ and an aromatic content of <1%; the iodine value of soybean oil fatty acid methyl ester is 135 g I2 / 100g.

[0056] The method for preparing environmentally friendly ink for high-speed offset printing machines in this embodiment includes the following steps:

[0057] S1. Add 65 parts of conjugated copolymerized gum oil, 12 parts of high-boiling-point alkane solvent, and 5 parts of soybean oil fatty acid methyl ester to a stirred tank and stir at 200℃ and 400 rpm until completely homogenized; dry mix 18 parts of phthalocyanine blue 15:3 pigment, 3.5 parts of silane-modified hollow ceramic microspheres, 5 parts of hydrophobically treated porous nano-silica, and 0.6 parts of polyethylene glycol dispersant evenly; slowly add this dry mixture to the homogenized mixture at 500 rpm; after the addition is complete, continue to disperse at 1500 rpm for 40 min under a vacuum of -0.08 MPa to obtain a pre-dispersed slurry;

[0058] S2. Transfer the pre-dispersed slurry obtained in S1 to a three-roll mill and perform multiple passes of fine grinding until the fineness of the sample is ≤5μm to obtain the base ink;

[0059] S3. Transfer the ground base ink to a conditioning kettle and cool it to 40°C; add 1 part of polyethylene micro powder wax and 0.3 parts of polydimethylsiloxane defoamer in sequence; mix at a low speed of 200 rpm for 60 min, and then cure the ink at a constant temperature of 40°C for 24 h.

[0060] S4. After the ink has matured, it is filtered through a 400-mesh stainless steel sieve to obtain the final product.

[0061] Example 3

[0062] This embodiment provides an environmentally friendly ink for a high-speed offset printing machine, comprising the following raw materials in parts by weight:

[0063] 55 parts of conjugated copolymerized gum oil, 8 parts of high-boiling-point alkane solvent, 3 parts of soybean oil fatty acid methyl ester, 15 parts of pigment (phthalocyanine blue 15:3), 2 parts of silane-modified hollow ceramic microspheres, 3 parts of hydrophobically treated porous nano silica, 0.5 parts of polyethylene micro powder wax, 0.3 parts of dispersant (polyethylene glycol), and 0.1 parts of defoamer (polydimethylsiloxane);

[0064] The preparation methods for conjugated copolymerized gum oils include:

[0065] Raw material ratio: 10 parts octylphenol rosin-modified phenolic resin, 25 parts mixed phenol-modified rosin-modified phenolic resin, 10 parts linseed oil, 30 parts soybean oil, 0 parts aluminum isooctanoate, and 1 part 2,6-di-tert-butyl-4-methylphenol. The weight-average molecular weight (Mw) of the octylphenol rosin-modified phenolic resin and the mixed phenol-modified rosin-modified phenolic resin used is 200,000, and the molecular weight distribution (Mw / Mn) is 3.

[0066] Octylphenol rosin-modified phenolic resin, mixed phenol-modified rosin-modified phenolic resin, linseed oil, and soybean oil were added to a reaction vessel. The mixture was heated to 200°C under stirring to melt and react the resin for 1.5 hours. Then the temperature was lowered to 100°C, and 2,6-di-tert-butyl-4-methylphenol and aluminum isooctanoate were added. The temperature was then raised to 160°C and held for 1.5 hours. The product was then discharged to obtain the conjugated copolymerized gum oil.

[0067] The preparation methods of silane-modified hollow ceramic microspheres include:

[0068] Raw material ratio: 100 parts by weight of hollow ceramic microspheres, 3 parts by weight of KH-570 silane coupling agent, 250 parts by weight of ethanol, 10 parts by weight of deionized water, and 0.4 parts by weight of glacial acetic acid.

[0069] Hollow ceramic microspheres were preheated at 75°C. In another container, KH-570, ethanol, water, and glacial acetic acid were mixed and stirred for 40 min to prepare a silane hydrolysate. The hydrolysate was sprayed through an atomizing nozzle onto the preheated microspheres at 75°C and a spray pressure of 0.4 MPa, and mixed at high speed for 50 min. The treated material was dried at 110°C for 3 h and passed through a 400-mesh sieve to obtain silane-modified hollow ceramic microspheres.

[0070] The preparation methods for hydrophobically treated porous nano-silica include:

[0071] 100 parts by weight of silicon dioxide, 7 parts by weight of hexadecyltrimethoxysilane, 350 parts by weight of toluene, and 0.8 parts by weight of ammonia solution with a mass concentration of 20 wt%.

[0072] Silica was dispersed in toluene and sonicated for 30 min. Then hexadecyltrimethoxysilane and ammonia were added and refluxed at 105 °C for 7 h. After the reaction was completed, the solid was separated by centrifugation, washed three times with toluene, and finally dried at 80 °C and -0.095 MPa vacuum for 8 h to obtain hydrophobic porous nano-silica.

[0073] Among them, the high-boiling-point alkane solvent has a boiling range of 270-310℃ and an aromatic content of <1%; the iodine value of soybean oil fatty acid methyl ester is 130 g I2 / 100g.

[0074] The method for preparing environmentally friendly ink for high-speed offset printing machines in this embodiment includes the following steps:

[0075] S1. Add 55 parts of conjugated copolymerized gum oil, 8 parts of high-boiling-point alkane solvent, and 3 parts of soybean oil fatty acid methyl ester to a stirred tank and stir at 175℃ and 400 rpm until completely homogenized; dry mix 15 parts of phthalocyanine blue 15:3 pigment, 2 parts of silane-modified hollow ceramic microspheres, 3 parts of hydrophobically treated porous nano-silica, and 0.3 parts of polyethylene glycol dispersant evenly; slowly add this dry mixture to the homogenized mixture at 500 rpm; after the addition is complete, continue to disperse at 1500 rpm for 60 min under a vacuum of -0.08 MPa to obtain a pre-dispersed slurry;

[0076] S2. Transfer the pre-dispersed slurry obtained in S1 to a three-roll mill and perform multiple passes of fine grinding until the fineness of the sample is ≤5μm to obtain the base ink;

[0077] S3. Transfer the ground base ink to a conditioning kettle and cool it to 35°C; add 0.5 parts of polyethylene micro powder wax and 0.1 parts of polydimethylsiloxane defoamer in sequence; mix at a low speed of 200 rpm for 90 min, and then cure the ink at 35°C for 36 h.

[0078] S4. After the ink has matured, it is filtered through a 400-mesh stainless steel sieve to obtain the final product.

[0079] Comparative Example 1

[0080] The difference between this comparative example and Example 1 is that 2.8 parts of "silane-modified hollow ceramic microspheres" were replaced with unmodified ordinary heavy calcium carbonate, while the rest were the same as in Example 1, and the preparation steps were the same as in Example 1.

[0081] Comparative Example 2

[0082] The difference between this comparative example and Example 1 is that four parts of "hydrophobicated porous nano-silica" were replaced with hydrophilic nano-silica with the same specific surface area but without hydrophobic treatment. The rest is the same as in Example 1, and the preparation steps are the same as in Example 1.

[0083] Comparative Example 3

[0084] The difference between this comparative example and Example 1 is that 2.8 parts of "silane-modified hollow ceramic microspheres" and 4 parts of "hydrophobicated porous nano-silica" were completely removed and replaced with an equal weight (6.8 parts) of high-boiling-point alkane solvent. The rest is the same as in Example 1, and the preparation steps are the same as in Example 1.

[0085] Comparative Example 4

[0086] The difference between this comparative example and Example 1 is that the preparation method of the silane-modified hollow ceramic microspheres used in this example does not involve silane hydrolysis and spray coating. Instead, the preheated hollow ceramic microspheres are directly dry-mixed at 1150 rpm for 45 min, then dried and sieved at 115°C. The rest of the preparation steps are the same as in Example 1.

[0087] Comparative Example 5

[0088] The difference between this comparative example and Example 1 is that the "silane-modified hollow ceramic microspheres" are replaced with an equal amount of untreated original hollow ceramic microspheres. Otherwise, the preparation steps are the same as in Example 1.

[0089] Comparative Example 6

[0090] The difference between this comparative example and Example 1 is that the "hydrophobicated porous nano silica" is replaced with an equal amount of untreated raw silica. Otherwise, the preparation steps are the same as in Example 1.

[0091] Comparative Example 7

[0092] The difference between this comparative example and Example 1 is that the "hydrophobicated porous nano-silica" (4 parts) was completely removed, and the amount of "silane-modified hollow ceramic microspheres" was increased to 6.8 parts to keep the total mass of the filler unchanged. The rest is the same as in Example 1, and the preparation steps are the same as in Example 1.

[0093] Comparative Example 8

[0094] The difference between this comparative example and Example 1 is that the "silane-modified hollow ceramic microspheres" (2.8 parts) were completely removed, while the amount of "hydrophobicated porous nano-silica" was increased to 6.8 parts to keep the total mass of the filler unchanged. The rest is the same as in Example 1, and the preparation steps are the same as in Example 1.

[0095] Experimental Example 1: The inks prepared in Examples 1-3 and Comparative Examples 1-8 were tested as follows:

[0096] Rheological properties: Dynamic oscillation test of ink was performed using a Hacker rheometer; test conditions were: temperature 25℃, frequency 1Hz, recording of viscous modulus (G'') and elastic modulus (G'), and calculation of its loss tangent (tgθ = G'' / G'), with a pass requirement of 1.0 < tgθ < 2.5;

[0097] High-speed printing adaptability: ① Transfer rate: Tested using an IGT printability tester at standard pressure and a printing speed of 1.0 m / s, measuring the ink transfer rate from the printing plate to the paper; the acceptable requirement is a transfer rate ≥ 60%. ② Ink splatter resistance: Using an ink viscosity meter, at the instrument's normal operating temperature, with the roller speed set to 1200 rpm, running continuously for 15 minutes, visually and instrumentally monitoring for ink splatter. The acceptable requirement is no clearly visible ink splatter.

[0098] Slope flow performance: The standard slope flow plate is used for testing. 0.5 mL of ink is placed at the starting point of the plate, and the instrument is started to tilt the plate at a standard rate. The maximum distance (mm) of ink flowing along the slope within 1 minute is recorded. The qualified requirement is a flow distance ≥80 mm, which characterizes the flow and spreading ability of ink under high shear rate.

[0099] Post-printing adaptability: The surface tension of the film layer 24 hours after ink printing and curing was tested using a dyne pen; the acceptable requirement is a surface tension ≥36 dyn, in order to evaluate its adaptability to post-printing processes such as lamination and varnishing.

[0100] Fineness: Tested according to GB / T 13217.3-2022, and the fineness of the ink was tested after standing for 30 days;

[0101] The results are shown in Table 1 below:

[0102]

[0103] The test data shows that the inks prepared in Examples 1-3 all meet the performance standards and exhibit excellent results. The key lies in the synergistic use of silane-modified hollow ceramic microspheres and hydrophobically treated porous nano-silica. The former, as lightweight and rigid hard spheres, mainly improves flowability, transfer rate, and provides structural support; the latter, as porous nanoparticles with high specific surface area, mainly provides thickening, thixotropic, system stabilization, and solvent anchoring functions. Together, they construct a rheological structure that balances the high elastic modulus (G') and moderate viscous modulus (G') required for high-speed offset printing, i.e., a qualified tgθ range. Furthermore, the hydrolytic spray treatment of the hollow ceramic microspheres with silane coupling agents and the hydrophobic treatment of the porous nano-silica with long-chain alkyl silanes are crucial to ensuring good compatibility, uniform dispersion, and long-term stability of these two fillers with the ink system based on vegetable oil esters and high-boiling-point alkane.

[0104] Comparative Example 1, using ordinary heavy calcium carbonate, resulted in deterioration of the ink's rheological properties, with excessively high tgθ, manifested as increased viscosity, decreased transfer rate, poorer anti-ink splatter properties, insufficient slope flowability, and reduced post-printing processing adaptability. After standing, the ink fineness significantly coarsened, indicating that the filler was unstable in the system, undergoing sedimentation or agglomeration. This demonstrates that ordinary fillers that are not surface-treated, have a high specific gravity, and are not hollow cannot meet the comprehensive requirements of high-speed offset printing inks for lightweighting, stability, and rheological properties.

[0105] Comparative Example 2, using hydrophilic nano-silica, resulted in an excessively high proportion of elastic components in the ink (lower tgθ). Although the transfer rate and anti-spray properties were acceptable, the fluidity deteriorated, and the ink exhibited poor compatibility within the system, potentially affecting post-printing processing performance. This demonstrates that hydrophobic treatment is crucial for the dispersion stability of nano-silica in oil-based systems and for regulating the rheological behavior of the ink.

[0106] In Comparative Example 3, after complete removal of the functional filler, the ink exhibited the worst rheological properties (extremely high tgθ), characterized by excessive viscosity, the lowest transfer rate, severe ink splatter, the worst flowability, and the worst post-printing processing performance. Although there was no filler sedimentation problem after standing, the system homogeneity may have been altered due to the lack of filler support. This fully demonstrates the indispensability of the synergistic effect of silane-modified hollow ceramic microspheres and hydrophobic porous nano-silica for constructing the specific rheological structure, transfer performance, and stability required for high-speed offset printing inks.

[0107] In Comparative Example 4, the silane was not hydrolyzed or spray-coated, resulting in poor modification effects. Compared to Example 1, the ink's rheological properties, transfer rate, and anti-ink-spray properties all decreased, but were still better than Comparative Example 5, which used the original microspheres directly. This indicates that the hydrolysis and uniform spray-coating process of the silane are key steps to ensure the formation of an effective and uniform hydrophobic graft layer of the coupling agent on the surface of the microspheres; simple dry mixing cannot achieve the desired results.

[0108] Comparative Example 5 used untreated hollow ceramic microspheres. Due to their hydrophilic surface, they had poor compatibility with the ink system, resulting in uneven dispersion and easy agglomeration. Their performance was inferior to Comparative Example 4, and far inferior to Example 1. This manifested as poor rheology, low transfer rate, severe ink splatter, poor flowability, and poor storage stability, with fineness increasing after standing. This directly demonstrates that silane modification of hollow ceramic microspheres is a necessary prerequisite for improving their dispersibility, compatibility, and functionality in inks.

[0109] Comparative Example 6 uses untreated raw silica. Due to the large number of hydrophilic silanol groups on its surface, it strongly adsorbs polar components in the ink system, resulting in an abnormally high elastic modulus (G') (lower tgθ) and poorer flowability. Its performance is similar to, but slightly better than, Comparative Example 2 because it retains some of the benefits of the porous structure. This again confirms the importance of hydrophobizing porous nano-silica to reduce its surface energy, improve its dispersion in oily carriers, and regulate its influence on rheological properties.

[0110] In Comparative Example 7, even with increased use of hollow microspheres after removing porous nano-silica, the ink's rheological properties (tgθ) remained viscous, with decreased transfer rate and anti-spill properties. Post-printing processing adaptability was acceptable, but storage stability deteriorated. This indicates that porous nano-silica not only provides thickening and thixotropic effects, but its porous structure also contributes uniquely to the formation of a stable three-dimensional network structure and the prevention of microsphere floating or system separation through its anchoring effect on the solvent / binder. These two functions are not entirely interchangeable.

[0111] In Comparative Example 8, even after removing the hollow ceramic microspheres and increasing the amount of porous silica, the proportion of elastic components in the ink remained relatively high (tanθ was low). The transfer rate was acceptable, but the anti-ink-splatter properties were only average. The flowability improved somewhat but did not reach its optimal level. This demonstrates that silane-modified hollow ceramic microspheres, as lightweight and rigid spherical particles, play an irreplaceable role in reducing the overall density of the ink, providing a ball bearing effect to improve flowability, and regulating rheological properties through the "hard ball" effect, i.e., increasing appropriate viscosity and preventing excessive elasticity.

[0112] In addition, printing tests were conducted on the inks of Examples 1-3 using a Heidelberg XL75 high-speed printing press, with the printing speed controlled at 16,000 sheets / hour. After one week of printing tests, there were no problems with ink application or dot gain, which met the printing requirements and showed no obvious ink splatter.

[0113] Finally, it should be noted that the above embodiments and comparative examples are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. An environmentally friendly ink for high-speed offset printing machines, characterized in that, The raw materials include the following parts by weight: 55-65 parts of conjugated copolymerized gum oil, 8-12 parts of high-boiling-point alkane solvent, 3-5 parts of soybean oil fatty acid methyl ester, 15-18 parts of pigment, 2-3.5 parts of silane-modified hollow ceramic microspheres, 3-5 parts of hydrophobically treated porous nano-silica, 0.5-1 part of polyethylene micro powder wax, 0.3-0.6 parts of dispersant, and 0.1-0.3 parts of defoamer; The conjugated copolymerized gum oil comprises the following raw materials in parts by weight: 10-25 parts of octylphenol rosin-modified phenolic resin, 10-25 parts of mixed phenol-modified rosin-modified phenolic resin, 10-30 parts of linseed oil, 10-30 parts of soybean oil, 0-1 parts of aluminum isooctanoate, and 1-5 parts of 2,6-di-tert-butyl-4-methylphenol.

2. The environmentally friendly ink for high-speed offset printing machines according to claim 1, characterized in that, The conjugated copolymerized gum oil is prepared by the following method: octylphenol rosin-modified phenolic resin, mixed phenol-modified rosin-modified phenolic resin, drying vegetable oil, and semi-drying vegetable oil are mixed and heated to 200-230℃ under stirring to melt and react the resin for 1-1.5 hours; then the temperature is lowered to 100-140℃, 2,6-di-tert-butyl-4-methylphenol and aluminum isooctanoate are added, the temperature is raised to 160-165℃, and the temperature is maintained for 1-1.5 hours to obtain the final product.

3. The environmentally friendly ink for high-speed offset printing machines according to claim 2, characterized in that, The weight-average molecular weight M of the octylphenol rosin-modified phenolic resin and the mixed phenol-modified rosin-modified phenolic resin is... w The molecular weight ranges from 200,000 to 250,000, with a molecular weight distribution M. w / M n It is 3-10.

4. The environmentally friendly ink for high-speed offset printing machines according to claim 1, characterized in that, The preparation method of the silane-modified hollow ceramic microspheres includes: preheating the hollow ceramic microspheres to 75-85℃, preparing a silane hydrolysate in another container, hydrolyzing KH-570, ethanol, water and glacial acetic acid for 30-40 min, spraying the hydrolysate into the microspheres at a spray pressure of 0.4-0.6 MPa, a temperature of 75-85℃, high-speed mixing at 1100-1200 rpm for 40-50 min, drying at 110-120℃ for 2-3 h, and passing the mixture through a 400-mesh sieve to obtain the product.

5. The environmentally friendly ink for high-speed offset printing machines according to claim 4, characterized in that, The weight ratio of the hollow ceramic microspheres, KH-570, ethanol, water and glacial acetic acid is 100:3-4:250-350:10-20:0.4-0.

6.

6. The environmentally friendly ink for high-speed offset printing machines according to claim 1, characterized in that, The method for preparing the hydrophobically treated porous nano-silica includes: dispersing silica in toluene, ultrasonicating for 30-40 min, adding hexadecyltrimethoxysilane and ammonia, refluxing at 105-115℃ for 5-7 h, centrifuging, washing, drying, and then obtaining the product.

7. The environmentally friendly ink for a high-speed offset printing machine according to claim 6, characterized in that, The ammonia solution has a mass concentration of 20-30 wt%, and the weight ratio of the silicon dioxide, hexadecyltrimethoxysilane, toluene and ammonia solution is 100:7-9:350-450:0.8-1.

2.

8. The environmentally friendly ink for high-speed offset printing machines according to claim 1, characterized in that, The specific surface area of ​​the silicon dioxide is 320 m². 2 / g, pore size 4-6nm.

9. The environmentally friendly ink for a high-speed offset printing machine according to claim 1, characterized in that, The high-boiling-point alkane solvent has a boiling range of 270-310℃ and an aromatic content of <1%; the soybean oil fatty acid methyl ester has an iodine value of 130-135g I2 / 100g; the pigment is phthalocyanine blue 15:3; the dispersant is polyethylene glycol; and the defoamer is polydimethylsiloxane.

10. A method for preparing an environmentally friendly ink for a high-speed offset printing machine as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Mix conjugated copolymerized gum oil, high-boiling-point alkane solvent, and soybean oil fatty acid methyl ester, and stir at 150-200℃ until homogenized; dry mix pigment, silane-modified hollow ceramic microspheres, hydrophobically treated porous nano silica and dispersant, and slowly add to the above mixture, and disperse under vacuum for 40-60 min. S2. Transfer the pre-dispersed material to a three-roll mill for grinding until the fineness is ≤5μm; S3. Cool the ground base ink to 35-40℃, add polyethylene micro powder wax and defoamer in sequence, stir for 60-90 minutes to mix evenly, and then cure at 35-40℃ for 24-36 hours. S4. The cured ink is obtained by filtering it through a 400-mesh sieve.

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